Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 07/09/13


AREA FORECAST DISCUSSION
NWS TUCSON AZ
900 AM MST SUN JUL 7 2013 .SYNOPSIS...HIGH PRESSURE ALOFT WILL BE NEAR THE FOUR CORNERS REGION THIS WEEK. ADEQUATE MOISTURE WILL PROVIDE ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS EARLY THIS WEEK WITH TEMPERATURES WELL ABOVE AVERAGE. ANOTHER SURGE OF MOISTURE WILL LEAD TO INCREASED THUNDERSTORM ACTIVITY BY WEDNESDAY. && .DISCUSSION...STILL SORTING THROUGH SOME DEBRIS THIS MORNING FROM OVERNIGHT CONVECTION IN NORTHWEST MEXICO. OVERALL WE HAVE A LITTLE LESS MOISTURE TO WORK WITH AS SOME MID LEVEL DRYING TRIES TO WORK IN BUT 12Z SOUNDING STILL HAD ABOUT 1.35 (IN LINE WITH BLENDED SATELLITE ESTIMATES) WHICH IS PLENTY TO WORK WITH. STILL A WEAK SOUTHERLY FLOW AT MOST LEVELS BUT A LITTLE BETTER THAN YESTERDAY. NOT THE GREATEST WIND AND THERMAL PROFILE FOR STRUCTURE BUT OVERALL SIMILAR TO YESTERDAY WITH SLIGHTLY BETTER SUPPORT FOR SLOW MOVING STORMS WANDERING INTO SOME VALLEY LOCATIONS. LATEST HI RES RR AND 12Z UOFA NAMWRF HAVE EASY DEVELOPMENT OVER MOUNTAIN LOCATIONS ON SCHEDULE WITH BETTER COVERAGE BY MID TO LATE AFTERNOON FOR SOME LOWER DESERT LOCATIONS SOUTHWEST AND WEST OF TUCSON IN AN AREA OF WEAK MOISTURE CONVERGENCE. WE ADJUSTED FIRST AND EARLY SECOND PERIOD TRENDS TO REFLECT THIS AS WELL AS A SLIGHT INCREASE IN VALLEY COVERAGE OVERALL. && .PREV DISCUSSION...HIGH PRESSURE ALOFT CENTERED OVER SRN NEW MEXICO EARLY THIS MORNING. UPPER HIGH IS PROGGED TO DRIFT NWD TO THE FOUR CORNERS REGION BY MON AFTERNOON...THEN REMAIN QUASI-STATIONARY THRU THURSDAY. SUFFICIENT MOISTURE WILL YIELD ISOLATED-SCATTERED SHOWERS/ TSTMS MOSTLY FROM TUCSON EWD/SWD THIS AFTERNOON AND THIS EVENING. COVERAGE OF SHOWERS/TSTMS IS EXPECTED TO GRADUALLY EXPAND WWD TO ENCOMPASS THE ENTIRE CWA BY WED AFTERNOON AND WED EVENING. THE 07/00Z ECMX MOS DEPICTS A SIGNIFICANT INCREASE IN POPS FOR KTUS TUE. AM SOMEWHAT CONCERNED ABOUT A POTENTIAL GULF OF CALIFORNIA SURGE AS EARLY AS TUE ATTRIBUTED TO TROPICAL SYSTEM ERICK. FOR NOW HAVE MAINTAINED A GRADUAL POP INCREASE TUE VERSUS MON. THUS...CHANCE- CATEGORY POPS EAST/SOUTH OF TUCSON TUE AFTERNOON AND TUE EVENING WITH A SLIGHT CHANCE OF SHOWERS/TSTMS FROM TUCSON WWD. POPS EXHIBIT A GRADUAL INCREASE WED-FRI AS DEEPER SELY FLOW IS PROGGED TO OCCUR IN RESPONSE TO THE UPPER HIGH BECOMING POSITIONED OVER THE CENTRAL CONUS. AT THIS TIME...TOO DIFFICULT TO DISCERN WHICH DAY MAY BE THE PROVERBIAL UP-DAY...AND WHICH DAY MAY HAVE A DOWNTURN IN CONVECTIVE ACTIVITY. AT ANY RATE...THERE IS A CHANCE OF MAINLY AFTERNOON/EVENING SHOWERS/TSTMS FROM TUCSON EWD/SWD WED-FRI... AND A SLIGHT CHANCE OF SHOWERS/TSTMS ACROSS WRN SECTIONS. HAVE CONTINUED WITH A SLIGHT DECREASE IN PRECIP CHANCES SAT. HIGH TEMPS FOR THE TUCSON METRO AREA THRU WED WILL AVERAGE ABOUT 3-5 DEGS F ABOVE NORMAL. DAYTIME TEMPS THUR-SAT ARE FORECAST TO BE WITHIN A DEGREE-OR-TWO OF NORMAL. && .AVIATION...VALID THRU 08/16Z... ISOLD-SCT TSRA FROM THIS AFTERNOON THROUGH 08/06Z. THUNDERSTORM WIND GUSTS 40-45 KTS WITH THE STRONGEST STORMS. OTHERWISE...12K FT SCT-BKN THROUGH THIS MORNING BECOMING 12K FT SCT CLOUDS THIS AFTERNOON WITH THE ISOLD-SCT TSRA. WIND GENERALLY AROUND 10 KTS AWAY FROM THE THUNDERSTORMS. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS. && .FIRE WEATHER...ISOLATED TO SCATTERED THUNDERSTORMS EACH AFTERNOON AND EVENING THROUGH TUESDAY ESPECIALLY IN THE HIGHER ELEVATIONS. BECOMING SCATTERED THUNDERSTORMS FROM WEDNESDAY THROUGH THE END OF THE WEEK. THE STRONGER THUNDERSTORMS WILL PRODUCE GUSTY AND ERRATIC WINDS. OTHERWISE...NORMAL DIURNAL WIND TRENDS WILL OCCUR THROUGHOUT THE WEEK. DAYTIME RELATIVE HUMIDITIES WILL RANGE FROM THE UPPER TEENS TO 30S WITH GOOD NIGHTTIME RECOVERIES. AN INCREASE IN RELATIVE HUMIDITY MID-WEEK COINCIDING WITH THE INCREASED STORM ACTIVITY. && .TWC WATCHES/WARNINGS/ADVISORIES...NONE. && $$ VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON MEYER/BF/SAMPSON
AREA FORECAST DISCUSSION
NWS TUCSON AZ
921 PM MST SAT JUL 6 2013 .SYNOPSIS...A RIDGE OF HIGH PRESSURE WILL BUILD OVER THE DESERT SOUTHWEST THIS WEEKEND EXPANDING EASTWARD EARLY NEXT WEEK. THIS RIDGE WITH OCCASIONAL WEAK DISTURBANCES ROTATING AROUND IT...COMBINED WITH MOISTURE ACROSS THE AREA WILL PROVIDE A CHANCE OF SHOWERS AND THUNDERSTORMS EARLY IN THE NEW WEEK. INCREASED ACTIVITY IS POSSIBLE THE SECOND HALF OF THE WEEK. && .DISCUSSION...WATER VAPOR IMAGERY SHOWS A SWATH OF MID LEVEL DRY AIR ACROSS MUCH OF THE EASTERN PACIFIC...CALIFORNIA...NORTHERN SONORA MEXICO AND SOUTHWEST ARIZONA. MEANWHILE...MORE MOIST AIR RESIDES TO THE EAST AND THIS INTERFACE BETWEEN THE DRIER AND MORE MOIST AIR IS SERVING AS A FOCUS FOR CONVECTIVE DEVELOPMENT WHICH TRIGGERED STORMS SOUTH OF NOGALES AND ALSO OVER THE TOHONO O`ODHAM NATION...CENTRAL PIMA COUNTY AND WESTERN PORTIONS OF PINAL COUNTY. THIS CLUSTER OF STORMS WILL CONTINUE TO MOVE TO THE NORTH BETWEEN MARANA AND CASA GRANDE THIS EVENING. ELSEWHERE ACROSS SOUTHEAST ARIZONA ISOLATED THUNDERSTORMS HAVE RECENTLY DEVELOPED ALONG THE ARIZONA/NEW MEXICO BORDER...ALONG INTERSTATE 10 NEAR SAN SIMON...AND THESE STORMS ARE ALSO MOVING NORTH. THE RUC HRRR MODEL INDICATED THAT THE CLUSTER OF STORMS NORTHWEST OF TUCSON AND INTO PINAL COUNTY WILL CONTINUE TO MOVE NORTH AND OUT OF MY FORECAST AREA THIS EVENING...WITH NO SIGNIFICANT DEVELOPMENT THEREAFTER. HOWEVER...GIVEN THE STORMS ALONG THE NEW MEXICO BORDER...AND OLD OUTFLOW BOUNDARIES MOVING HERE AND THERE...WILL KEEP SOME MENTION OF ISOLATED SHOWERS AND THUNDERSTORMS IN THE FORECAST THROUGH THE REMAINDER OF THE NIGHT. AS OF 04Z (9 PM MST)...TEMPERATURES ACROSS THE REGION RANGED FROM THE MID 70S TO THE LOWER 90S...WITH THE TUCSON INTL AIRPORT REPORTING A TEMP OF 93 DEGS AFTER REACHING A HIGH OF 103 DEGS. THESE CURRENT READINGS SEEM TO BE ON TRACK WITH REGARD TO THE OVERNIGHT LOWS...SO NO CHANGES ARE PLANNED AT THIS TIME...BUT WILL CONTINUE TO MONITOR. && .AVIATION...ISOLATED TO SCATTERED T-STORMS MAINLY NORTHWEST OF TUCSON THROUGH AROUND 06Z...THEN ONLY EXPECTING ISOLATED TSTMS THEREAFTER. WIND GUSTS WILL APPROACH 40-45 KTS WITH THE STRONGEST TSTMS THROUGH 06Z. OTHERWISE...VFR CONDITIONS WITH DIURNALLY DRIVEN WINDS TO OCCUR THRU SUNDAY AFTERNOON. ANOTHER ROUND OF ISOLATED TO SCATTERED TSTMS DEVELOPING AGAIN LATE SUNDAY AFTERNOON AND INTO THE EVENING HOURS. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS. && .FIRE WEATHER...ON SUNDAY...EXPECT ISOLATED TO SCATTERED AFTERNOON/EVENING THUNDERSTORMS. THEREAFTER...SCATTERED MAINLY AFTERNOON AND EVENING THUNDERSTORMS WILL OCCUR DURING THE UPCOMING WEEK FROM TUCSON EASTWARD...WITH ISOLATED THUNDERSTORMS WEST OF TUCSON. THE STRONGER THUNDERSTORMS WILL PRODUCE STRONG...GUSTY AND ERRATIC WINDS. OTHERWISE...NORMAL DIURNAL WIND TRENDS WILL OCCUR THIS WEEKEND AND DURING THE UPCOMING WEEK. DAYTIME RELATIVE HUMIDITIES NEXT WEEK WILL RANGE FROM THE MID TEENS TO 20S WITH GOOD NIGHTTIME RECOVERIES. && .CLIMATE...TODAY HAS BEEN THE 36TH CONSECUTIVE DAY WITH TEMPERATURES IN EXCESS OF 100 DEGREES AT TUCSON INTERNATIONAL AIRPORT...4TH LONGEST ALL TIME. && .PREVIOUS DISCUSSION...WITH WEAK FLOW AND STRUCTURE WE WILL PROBABLY LIMP ALONG AT A LOW GRADE THUNDERSTORM FORECAST TO START THE NEW WEEK. THE HIGH PRESSURE AND LESS PERVASIVE CLOUD COVER SHOULD ALLOW FOR TEMPERATURES ON THE HOTTER SIDE 5 TO 8 DEGREES ABOVE CLIMO. SURGE ACTIVITY ASSISTED BY TROPICAL INFLUENCES AS EARLY AS TUESDAY NIGHT WITH AN INVERTED TROUGH PUSHING ACROSS PORTIONS OF NORTHWEST MEXICO BY MID WEEK. && .TWC WATCHES/WARNINGS/ADVISORIES...NONE. && $$ VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON CURRENT DISCUSSION...MOLLERE PREVIOUS DISCUSSION...MEYER/GLUECK
AREA FORECAST DISCUSSION
NWS EUREKA CA
425 AM PDT SUN JUL 7 2013 .SYNOPSIS...EXPECT A TRANQUIL WEATHER PATTERN WITH SEASONAL TEMPERATURES THIS WEEK. THE INTERIOR SHOULD BE MOSTLY CLEAR WHILE THE COAST CAN EXPECT OVERNIGHT CLOUDS AND FOG WITH CLEARING EACH AFTERNOON. && .DISCUSSION...THE FORECAST REMAINS ON TRACK. CLOUDS OVER PORTIONS OF NORTHWEST CALIFORNIA SHOULD DISSIPATE THIS MORNING AND AFTERNOON, THOUGH PROBABLY NOT AS QUICKLY AS DAYS PAST SINCE THE MARINE LAYER IS MORE ENTRENCHED ALONG THE COAST THIS MORNING. BUT WHEN THE CLOUDS DO DISSIPATE ONE CAN EXPECT A NICE SUMMER DAY. EXPECT A TRANQUIL WEATHER PATTERN WITH SEASONAL TEMPERATURES THIS WEEK. SKIES WILL BE CLEAR ACROSS THE INTERIOR WITH SOME AFTERNOON CLOUDS OVER THE HIGHER TERRAIN. WINDS THERE WILL BE MOSTLY LIGHT AND TERRAIN-DRIVEN DURING THE DAY AND THEN LIGHT AND OFFSHORE AT NIGHT. THE COAST CAN EXPECT OVERNIGHT CLOUDS AND FOG WITH CLEARING EACH AFTERNOON. MINOR COOLING IS EXPECTED BY THE MIDDLE OF THE WEEK AS A WEAK TROUGH PASSES OVER THE WEST COAST. BUT TEMPERATURES SHOULD ONLY COOL A FEW DEGREES, MAINLY ACROSS THE INTERIOR. && .AVIATION...LOW CLOUDS AND SOME LIGHT FOG CONTINUE TO HUG THE NW CA COAST WITH CLOUDINESS EXTENDING INLAND UP THE COASTAL RIVER VALLEYS N OF CAPE MENDO. AGREE WITH PREVIOUS FORECASTER WITH LATER CLEARING TIME AT KACV TODAY. CURRENT TAF SET HAS ABOUT A 7 HOUR WINDOW OF NO CIG AT KACV AND THIS MAY ACTUALLY NEED TO BE NARROWED...BUT BOTH THE NAM AND RUC HINT THAT CLOUDINESS SHOULD SCATTER OUT AROUND 21Z. TRICKIER FORECAST AT KCEC. NAM AND RUC GRIDDED DATA SHOW MINIMAL CLOUD COVER DURING THE DAY...BUT NAM AND GFS MOS SHOW CIGS MOST OF THE DAY. LOW CLOUDS HAVE EXPANDED N ALONG THE COAST TO KCEC OVER THE PAST SEVERAL HOURS ON COASTAL S FLOW. EXPECT NORTHERLIES TO RETURN LATER THIS MORNING. THIS...IN CONCERT WITH EROSION FROM THE E DUE TO DAYTIME HEATING AND AN AREA OF DOWNSLOPING UPSTREAM...MAY HELP CLOUDS ERODE BY LATE MORNING OR EARLY AFTERNOON. LOW CLOUDS HAVE REACHED KSTS. WITH LIGHT S FLOW AROUND THAT AREA...WILL NEED TO WATCH THIS CLOUD DECK IN CASE IT MAKES A RUN AT KUKI. OTHERWISE...VFR EXPECTED AT THAT AIRPORT. /SEC && .MARINE...RATHER STRAIGHTFORWARD FORECAST DOMINATED BY SHORT PERIOD WIND DRIVEN WAVES THRU THE PERIOD. HAVE EXTENDED THE N OFFSHORE GALE WARNING THRU THE AFTERNOON HOURS DUE TO WIND GUSTS. THIS MAY NEED TO BE EXPANDED FURTHER BY THE DAY SHIFT. OTHER HEADLINES REMAIN UNCHANGED. SWAN MODEL APPEARS TO HAVE A BETTER HANDLE ON WAVE HEIGHTS WITH INITIALIZATION MATCHING FAIRLY WELL WITH LOCAL BUOYS. WINDS ARE FORECAST TO SLOWLY DECREASE INTO TUE...THEN PICK UP A BIT AROUND MID-WEEK. /SEC && .EKA WATCHES/WARNINGS/ADVISORIES... CA...NONE. NORTHWEST CALIFORNIA COASTAL WATERS... GALE WARNING FOR PZZ470. HAZARDOUS SEAS WARNING FOR PZZ475. SMALL CRAFT FOR PZZ450-455-475. && $$ VISIT US AT HTTP://WWW.WEATHER.GOV/EUREKA FOLLOW US ON FACEBOOK AND TWITTER AT: HTTP://WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.EUREKA.GOV HTTP://WWW.TWITTER.COM/NWSEUREKA
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1119 PM MDT SAT JUL 6 2013 .UPDATE... ISSUED AT 725 PM MDT SAT JUL 6 2013 UPDATED TO BUMP UP POPS ACROSS THE FAR EASTERN PLAINS WHERE CLUSTER OF SHOWERS/THUNDERSTORMS CONTINUES. 23Z HRRR SLOWLY SHIFTS THIS EASTWARD AND HANGS ON TO SOME SPOTTY QPF NEAR THE EASTERN BORDER AFTER MIDNIGHT. IT ALSO DEVELOPS ANOTHER BAND OF SHOWERS/EMBEDDED THUNDERSTORMS ACROSS THE CENTRAL MOUNTAINS WHICH SHIFTS INTO THE SOUTHEAST MOUNTAINS AROUND 06Z BEFORE DIMINISHING AS IT HEADS EASTWARD ACROSS THE SOUTHERN I-25 CORRIDOR AFTER 10Z. SO FAR...HRRR SEEMS OVERDONE WITH THIS LATER BATCH OF CONVECTION...BUT HAVE INTRODUCED SOME ISOLATED POPS OVER THE MOUNTAIN AREAS THROUGH 08Z TO ACCOUNT FOR THE POSSIBILITY OF LINGERING CONVECTION WITHIN MOISTURE PLUME. WILL WAIT FOR 00Z NAM12 RUN TO ARRIVE BEFORE EXTENDING POPS THROUGH THE NIGHT FOR MOST AREAS AS HRRR SUGGESTS. -KT && .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 245 PM MDT SAT JUL 6 2013 ...EARLY GLIMPSE OF THE MONSOON UNDERWAY... EARLY MONSOONAL AIRMASS OVER SOUTHERN COLORADO THIS WEEKEND WITH SURFACE DEWS NOW IN THE 40S AND 50S PRETTY MUCH ANY WHICH WAY YOU LOOK. ALOFT...PLENTY OF MID/HIGH LEVEL MONSOON MOISTURE CIRCULATING AROUND LARGE MEW MEXICO HIGH PRESSURE AREA. VERY LITTLE COLD AIR ALOFT ASSOCIATED WITH LARGE HIGH SETTING THE STAGE FOR TYPICAL DIURNAL AFTERNOON AND EVENING THUNDERSTORM ACTIVITY PRODUCING MOSTLY RAIN AND MAYBE A LITTLE BIT OF SMALL HAIL...WITH OTHER THREATS INCLUDING LIGHTNING AND LOCALLY GUSTY WINDS UP TO AROUND 50 MPH. MONSOONAL MOISTURE IS NOT REAL GREAT YET...WITH PRECIPITABLE WATERS RANGING FROM A SOUTHERN COLORADO MAX OF A LITTLE OVER AN INCH ACROSS THE SOUTHEAST TIP OF BACA COUNTY TO A MIN AROUND 3 QUARTERS OF AN INCH ACROSS THE NORTHWEST TIP OF LAKE COUNTY. BUT...SURELY BETTER THAN A COUPLE DAYS AGO...AND ADEQUATE FOR SOME LOCALLY HEAVY RAINERS. THERE IS CERTAINLY ENOUGH WATER IN THE ATMOSPHERE FOR CONCERN OVER SOME OF THE NEWER AREA BURN SCARS INCLUDING THE WALDO...EAST PEAK AND WEST FORK SCARS. VIGILANCE MUST CONTINUE IN THESE AREAS FOR THE FORESEEABLE FUTURE...STARTING WITH THIS AFTERNOON AND EVENING. AS IN RECENT DAYS...MOST THUNDERSTORM ACTIVITY SHOULD DIE DOWN ACROSS THE AREA BY AROUND 04Z OR SO...WITH CONVECTIVE DEBRIS LINGERING AND GRADUALLY DISSIPATING AFTER THAT. FEEL THAT MOST ACTIVITY WILL BE COMPLETELY OVER BY MIDNIGHT...ALTHOUGH THERE COULD BE A FEW STRAGGLERS THROUGH THE NIGHT...COVERING LESS THAN ONE PERCENT OF THE FORECAST AREA. LW .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 245 PM MDT SAT JUL 6 2013 ...MONSOON SEASON IS UPON US... LOOKS LIKE A FAIRLY NORMAL SUMMER PATTERN WILL BE WITH US FOR THE COMING WEEK. FORECAST TEMPS AND PRECIP WILL BE INFLUENCED BY THE OVERALL PATTERN...INCLUDING THE POSITION OF THE RIDGE AND H5 HIGH OVER THE SW U.S. THE UPPER HIGH WILL START OFF OVER THE 4 CORNERS REGION ON MONDAY AND TUESDAY. THIS CAN BE A FAVORABLE MONSOONAL PATTERN...BUT IN THIS PARTICULAR CASE THE UPPER RIDGE WILL BE FLATTENED BY A SHORT WAVE MOVING THROUGH SW AND SRN CANADA...SO UPPER WINDS WILL BE GENERALLY WESTERLY AND BRINGING RELATIVELY DRY AIR IN FROM THE W AND SW. HOWEVER...THE SHORTWAVE COULD SPARK A FEW HIGH BASED STORMS...PARTICULARLY OVER THE ERN MTS AND PLAINS LATE MONDAY AND AGAIN ON TUESDAY. TUESDAY NIGHT...A WEAK FRONT ASSOCIATED WITH THE SHORT WAVE NOW MOVING INTO THE GREAT LAKES REGION WILL PUSH OVER ERN CO. THE UPPER HIGH WILL HAVE MIGRATED SLIGHTLY EWD INTO NW NM. THIS WILL SET THE STAGE FOR AN UP-TICK IN PRECIP ON WED...ESPECIALLY OVER THE MTS BUT EXTENDING EWD ONTO THE PLAINS BY WED EVE. THURSDAY...THE MONSOON PLUME RETURNS TO WRN CO AS THE UPPER HIGH CONTINUES TO DRIFT SLIGHTLY TO THE W OVER NRN NM. A FAIRLY ROBUST MOISTURE PLUME THEN LOOKS TO AFFECT THE AREA FRI AND THROUGH THE WEEKEND. AT THIS TIME...IT LOOKS LIKE THE BULK OF THE HEAVIER CONVECTION WILL BE OVER THE CENTRAL MTS...WHICH COULD BRING AN INCREASED THREAT OF FLASH FLOODING TO THE MT AREAS...AND PARTICULARLY THE WEST FORK BURN...THROUGH THE WEEKEND. DAYTIME HIGH TEMPS WILL BE A BIT TRICKY TO FORECAST THIS COMING WEEK. THE H5 HEIGHTS AND H7 TEMPS JUSTIFY HIGH TEMPS IN THE UPPER 90S OR EVEN LOW 100S FOR SEVERAL DAYS OVER THE LOWER ARKANSAS AND ERN PLAINS. AT THIS TIME...SINCE THE MONSOONAL MOISTURE APPEARS TO AFFECT MAINLY THE CENTRAL MTS...IF IT STAYS DRY ENOUGH THESE HIGH TEMPS WILL BE REALIZED...AND THIS IS WHERE THE FORECAST TREND HAS BEEN FOR THE DAILY HIGHS. HOWEVER...IT DOES APPEAR THAT AT LEAST MODEST MID LEVEL MOISTURE WILL BE TRAPPED UNDER THE RIDGE...AND COULD BRING AT LEAST ISOLD TO SCT CONVECTION OVER THE PLAINS EACH DAY. IF THIS HAPPENS...THEN THE DAY TIME HIGHS COULD BECOME A RACE BETWEEN REALIZING THE WELL MIXED VALUES DOWN FROM H7-H5...AND THE DEVELOPMENT OF EARLY AFTERNOON THUNDERSTORMS...WHICH COULD BRING DOWN TEMPS IN A HURRY FOR THE PLAINS. HOPEFULLY...THE PLUME WILL SHIFT FAR ENOUGH E AT SOME POINT THAT MORE DEEP MOISTURE CAN MOVE OVER THE PLAINS. ROSE && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 1116 PM MDT SAT JUL 6 2013 VFR CONDITIONS EXPECTED ACROSS THE FORECAST AREA...INCLUDING THE 3 MAIN TAF SITES OF KCOS...KPUB AND KALS...FOR THE NEXT 24 HRS. THERE IS THE THREAT OF ISOLATED TO SCATTERED CONVECTION FIRING OVER THE HIGHER TERRAIN EACH AFTERNOON...THEN MOVING EAST ACROSS THE ADJACENT PLAINS THROUGH THE LATE AFTERNOON AND EARLY EVENING. PRIMARY STORM THREATS INCLUDE LIGHTNING...PERIODS OF HEAVY RAIN...AND GUSTY ERRATIC WINDS UP TO 50 MPH. && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...KT SHORT TERM...LW LONG TERM...ROSE AVIATION...MOORE
AREA FORECAST DISCUSSION
NWS TAUNTON MA
756 PM EDT MON JUL 8 2013 .SYNOPSIS... A COLD FRONT WILL CONTINUE TO PUSH SOUTH INTO SOUTHERN NEW ENGLAND TODAY. THE FRONT WILL STALL THIS EVENING ACROSS SOUTHERN NEW ENGLAND AND LINGER ACROSS THE AREA TOMORROW...FOLLOWED BY A WARM FRONT ALLOWING FOR MORE WIDESPREAD PRECIPITATION ON WEDNESDAY. TEMPERATURES WILL BE LESS HOT...BUT THE HUMIDITY WILL LINGER. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... 730 PM UPDATE... KBOX 88D SHOWING TWO MESOSCALE BOUNDARIES VERY WELL AS THEY CRIS- CROSS SOUTHERN NEW ENGLAND. LATEST HRRR RUN HAD THE RIGHT IDEA WITH DEVELOPING STORMS ALONG THESE BOUNDARIES...BUT WAS PERHAPS A BIT TOO AGGRESSIVE IN ITS COVERAGE. LOWERED POPS SLIGHTLY THIS EVENING DUE TO THE ISOLATED NATURE OF THE CONVECTION. STILL EXPECTING IT TO FIZZLE WITHIN A FEW HOURS AS WE GET PAST SUNSET. STORMS ARE MOVING...AND WHILE SOME ARE PUTTING DOWN DECENT RAINFALL RATES...WE NO LONGER EXPECT SIGNIFICANT FLOODING ISSUES. AS SUCH THE FLASH FLOOD WATCH WAS CANCELED. ONLY OTHER CHANGES WERE TO TWEAK TEMPERATURES AND DEW POINTS TO BRING THEM INTO LINE WITH OBSERVED TRENDS. PREVIOUS DISCUSSION... FOCUSING ON THE STORM POTENTIAL THREAT...CONTINUED TO HAVE LOW CONFIDENCE. STORM ANALYSIS SHOWS THAT ML CAPE VALUES ARE AROUND 1000 J/KG WHILE BULK SHEAR IS NEAR 20-35 KTS ESPECIALLY ACROSS EASTERN MA. PWAT VALUES ARE NEARING 1.7 INCHES SO MAIN CONCERN FOR ANY CONVECTION AT THIS POINT IS HEAVY RAIN AND LIGHTNING. LOW LEVEL LAPSE RATES ARE NEARING 7-8 C/KM WHILE SURFACE LI ARE -4. DESPITE ALL OF THESE FACTORS...CELLS CONTINUE TO STRUGGLE THIS AFTERNOON DUE TO LACK OF DEEP MOISTURE. HOWEVER SOME MESOSCALE MODELS DO INDICATE THAT THIS MOISTURE WILL FILTER INTO WESTERN NEW ENGLAND LATER THIS AFTERNOON...AROUND 20-22Z SO THIS AREA MAY NEED TO BE WATCHED. FLASH FLOODING IS ALSO A CONCERN AS STORMS MAY TRAIN A LITTLE. HAVE EXPANDED THE FLASH FLOOD WATCH AS THE BETTER POTENTIAL FOR THE STRONG STORMS LOOKS TO BE ACROSS CENTRAL INTO NE MASS AS WELL S NH. THEREFORE CONTINUED THE WATCH IN HOPE THAT A CLEARER PICTURE FOR STORM DEVELOPMENT POTENTIAL OCCURS WITHIN THE HOUR. TONIGHT...ANY CONVECTION THAT DEVELOPS SHOULD WANE AFTER SUNSET AS DIURNAL HEATING IS LOST. SOME MESOSCALE MODELS TO INDICATE THAT A FEW SHOWERS WILL LINGER TIL AFTER MIDNIGHT. OTHERWISE THE FOCUS TURNS TO THE FOG POTENTIAL FOR TONIGHT. CURRENT VISIBLE SATELLITE IMAGERY SHOWS A GOOD STRATUS DECK JUST OFFSHORE OF THE EAST COAST SO EXPECT THAT TO FILTER IN ONCE THE DIURNAL HEATING IS LOST. BUFKIT SOUNDING ALSO SHOW FOG DEVELOPMENT ACROSS THE REGION ALONG ALL SHORES. THE BEST CHANCE IS ACROSS THE EAST COAST AS BOUNDARY WILL ALLOW FOR EASTERLY FLOW OVERNIGHT. SOUTH SHORE WILL BE LESS OF A SHOT BUT STILL BELIEVE ITS A POSSIBILITY. NO DENSE FOG ADVISORY AT THIS TIME. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/... TOMORROW...SOME UNCERTAINTY LIES FOR TOMORROW. HAVE A LOW CONFIDENCE IN THE OVERALL FORECAST. SLIGHT RIDGING IN THE MID- LEVELS WILL LOWER THE CHANCE FOR STORMS TOMORROW. HOWEVER SEEMS THAT THE SOUTHERN HALF OF THE REGION MAY HAVE A POTENTIAL. STILL UNCERTAIN ON WHERE EXACTLY THIS BOUNDARY WILL END UP. MODELS INDICATE THAT IT WILL WORK ACROSS CT/RI AND SE MA...HOWEVER WE LOSE THE UPPER LEVEL SUPPORT. THEREFORE HAVE DECIDED NOT TO ISSUE A FLASH FLOOD WATCH FOR TOMORROW AS THERE IS A LOT OF UNCERTAINTY. HOPEFULLY THE MIDNIGHT CREW WILL GET A BETTER SET OF GUIDANCE THAT WILL HELP DETERMINE WHAT WILL HAPPEN FOR TOMORROW. EASTERLY FLOW WILL STILL CONTINUE ACROSS THE EASTERN PORTION OF THE REGION SO TEMPS WILL CONTINUE TO BE COOLER ACROSS THE EAST PORTION. WHERE AS THE SOUTHERN PORTION SHOULD SEE THE HIGHER TEMPS. && .LONG TERM /TUESDAY NIGHT THROUGH MONDAY/... HIGHLIGHTS... * WARM AND HUMID CONDITIONS CONTINUE THROUGH MOST OF THIS WEEK * A BETTER CHANCE FOR MORE WIDESPREAD SHOWERS AND STORMS WED-FRI OVERVIEW AND MODEL PREFERENCES... LONG RANGE GUIDANCE SUITE CONTINUES TO SHOW RELATIVELY DECENT AGREEMENT REGARDING THE LONG TERM SETUP BUT HAVE DISAGREEMENTS LATE THIS WEEK AND WEEKEND REGARDING THE AMPLITUDE OF THE MID-LEVEL FLOW PATTERN. WPC CONTINUES TO FAVOR THE ECENS MEAN...WHICH WITH THIS LATEST SET OF MODEL RUNS...HAS SUPPORT FROM BOTH THE GEFS MEAN AND EVEN THE OPERATIONAL GFS TO SOME EXTENT WHILE THE ECMWF OPERATIONAL RUN APPEARS TO BE THE MORE MERIDIONAL OUTLIER. THEREFORE...TO KEEP CONSISTENCY GIVEN THE LOWER CONFIDENCE IN THE EXACT SET UP BY NEXT WEEKEND...WILL CONTINUE TO TREND THE FORECAST GRIDS WITH THE ECENS VIA THE WPC...WITH BIT OF THE LATEST GFS GIVEN THE AGREEMENT. FOR THE SLIGHTLY SHORTER TIMERANGE...A GENERAL MODEL BLEND SHOULD PROVIDE ADEQUATE TIMING GIVEN VERY GOOD AGREEMENT THOUGH THURSDAY. CURRENT EXPECTATIONS ARE FOR THE RIDGING OVER THE ATLANTIC TO BREAK DOWN OVER THE COURSE OF THIS WEEK...WITH A HIGH AMPLITUDE MID-LEVEL TROUGH ARRIVING LATE THIS WEEK INTO THIS WEEKEND. THE QUESTION WHICH REMAINS IS HOW LONG THIS TROUGH WILL BE ABLE TO LINGER IN OUR VICINITY EARLY NEXT WEEK. THERE IS ALSO THE ISSUE WITH THE PROXIMITY OF THE BERMUDA HIGH REESTABLISHING ITSELF EARLY NEXT WEEK. LOTS OF UNCERTAINTY REGARDING THIS PORTION OF THE FORECAST. DETAILS... TUESDAY NIGHT INTO WEDNESDAY...ANY CONVECTION THAT WAS ALLOWED TO FIRE WITHIN THE WEAK UPPER LEVEL RIDGE ON TUESDAY IS EXPECTED TO COME TO AN END EARLY TUESDAY NIGHT WITH A PERIOD OF GENERALLY DRY CONDITIONS INTO THE EARLY DAY WED. DURING THE DAY WEDNESDAY...A SURFACE WARM FRONT WILL APPROACH THEN CROSS THE REGION LATE IN THE DAY. WILL BE CONTINUING WITH CHANCE AND LIKELY POPS WITH THIS FEATURE. THIS IS PRIMARILY DUE TO DEEP MOISTURE AND SOME CONDITIONAL INSTABILITY IN MODEL SOUNDINGS ALONG WITH THE FRONT COMBINED WITH THE LIFT AND SHEAR TYPICALLY COINCIDENT WITH THESE WARM FRONTS. THE KEY TO HOW MUCH/STRONG ANY POTENTIAL CONVECTION WILL BE IS DEPENDENT SOMEWHAT ON THE EARLY MORNING CLOUD COVER...WHICH MAY BE NEAR BKN-OVC GIVEN REMNANT CONVECTIVE DEBRIS. THURSDAY AND FRIDAY...THERE ARE TIMING ISSUES HERE LIKELY DUE TO THE DIFFERENCES REGARDING HOW DEEP A POTENTIAL EASTERN CONUS CUTOFF DEVELOPS. HOWEVER...DO EXPECT A SLOWING COLD FRONT TO MOVE ACROSS THE REGION FROM THE WEST...POTENTIALLY STALLING NEAR THE SOUTH COAST BY FRIDAY. INITIALLY...GIVEN IT APPEARS MUCH OF SRN NEW ENGLAND WILL BREAK INTO THE WARM SECTOR AHEAD OF THIS FRONT...IT APPEARS INSTABILITY WILL BE ENOUGH TO SUPPORT SOME CONVECTION WITH DECENT SHEAR AND VERY HIGH /NEAR 2.0 INCHES AGAIN/ PRECIPITABLE WATER VALUES. THE HIGHER POTENTIAL FOR STRONGER CONVECTION APPEARS TO BE THURSDAY...ESPECIALLY IF THE SLOWER SOLUTION IS CORRECT SINCE IT WILL ARRIVE LATE IN THE DAY AND A FRONT WILL LIKELY STALL NEARBY. HOWEVER...THE PERIOD LOOKS TO BE WET WITH SOME DRYING POSSIBLE FROM NW TO SE LATE AS THE DRIER AIR BEHIND THIS FRONT FILTERS IN. IT/S DIFFICULT TO SAY HOW QUICKLY THIS WILL OCCUR...SO WILL BE KEEPING MOSTLY CHANCE TO SLIGHT CHANCE POPS AROUND THE REGION THROUGH THE PERIOD. TEMPS WILL TRANSITION TO LIKELY ABOVE NORMAL TO NEAR- SLIGHTLY ABOVE NORMAL...BUT HUMIDITY WILL REMAIN HIGH. THIS COMING WEEKEND... A FAIR AMOUNT OF UNCERTAINTY REGARDING SENSIBLE WEATHER DETAILS THIS PERIOD WHICH WILL BE STRONGLY DEPENDENT ON WHERE A SOUTH TO NORTH MOISTURE STREAM AND LOW LEVEL FRONT ULTIMATELY SET UP. DESPITE THE UPPER LVL SIMILARITIES BETWEEN THE ECENS AND GFS HERE...THEIR SFC FEATURES ARE IN DISAGREEMENT. SHOULD THIS FRONT AND MOISTURE STREAM HOLD CLOSER TO THE COASTLINE /MORE SIMILAR TO ECENS/ THIS PERIOD WOULD LIKELY BE WET. THE GFS IS A BIT DRIER BECAUSE IT IS QUICKER ALLOWING FOR THE RETROGRADING BERMUDA HIGH TO ONCE AGAIN INFLUENCE THE WX. WILL AT LEAST BE SUGGESTING SOME POPS THROUGH THE PERIOD AS EVEN THE DRIER GFS WOULD SUGGEST THE POSSIBILITY OF DIURNAL CONVECTION WHILE THE ECENS WOULD BE MORE BROADLY WET. EARLY NEXT WEEK... ONCE AGAIN A FAIR AMOUNT OF UNCERTAINTY...BUT SHOULD THE BERMUDA HIGH AND WESTERN ATLANTIC RIDGE BEGIN TO MOVE WEST WITH TIME...A TRANSITION TOWARD HOTTER WEATHER IS POSSIBLE. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. .SHORT TERM...TODAY THROUGH TUESDAY... AFTER 00Z...SHOWERS/TSTMS CONTINUE EARLY AT NIGHT AND THEN DIMINISH. ONCE AGAIN AREAS OF FOG/LOW CLOUDS ALONG THE SOUTH COAST ESPECIALLY THE CAPE AND ISLANDS. PATCHY FOG WITH REDUCED CIGS/VSBYS ALSO POSSIBLE INLAND ESPECIALLY AT AIRPORTS THAT SAW RAIN IN THE AFTERNOON/EVE. ALSO EXPECTING A FOG/STRATUS BANK EAST OF MA TO MOVE WEST WITH THE EASTERLY FLOW AND COOLING BOUNDARY LAYER. THIS WILL INCLUDE KBOS. TUESDAY... ANOTHER DISTURBANCE RIDES ALONG THE STALLED FRONT AND BRINGS ANOTHER ROUND OF SHOWERS/TSTMS. AS WITH TODAY...CONDITIONS WILL GENERALLY BE VFR BUT WITH TSTMS GENERATING LOWER CIGS/VSBYS. KBOS TERMINAL...MODERATE CONFIDENCE IN TAF. MORE CERTAINTY WITH TRENDS. LOW CONFIDENCE ON TIMING SPECIFICS. KBDL TERMINAL...MODERATE CONFIDENCE IN TAF. MORE CERTAINTY WITH TRENDS. LOW CONFIDENCE ON TIMING SPECIFICS. OUTLOOK...TUESDAY NIGHT THROUGH SATURDAY... CONTINUED HIGH CONFIDENCE IN OVERALL TRENDS BUT LOWER CONFIDENCE IN EXACT TIMING OF ANY LOWER CATEGORIES THROUGH THE PERIOD. LITTLE CHANGE IN THE EXPECTED CONDITIONS WITH THIS UPDATE. MAINLY VFR IS EXPECTED UNTIL AT LEAST WEDNESDAY. THE ONLY CAVEATS WILL BE THE THREAT FOR OVERNIGHT MVFR/IFR CONDITIONS IN LOCALIZED FOG AND AN OCCASIONAL MVFR VSBY/CIG IN ISOLATED SHOWERS/T-STORMS DURING THE AFTERNOONS/EVENINGS. THESE WILL BE VERY LOCALIZED AND ARE NOT EXPECTED TO AFFECT ALL AIRPORTS. A STRONGER SYSTEM MAY ALLOW FOR MORE WIDESPREAD MVFR/IFR CONDITIONS WEDNESDAY THROUGH THURSDAY WITH MORE WIDESPREAD RAINFALL. THESE CONDITIONS LIKELY TO LINGER INTO FRIDAY AS A COLD FRONT APPROACHES FROM THE WEST. VFR MORE LIKELY ACROSS THE INTERIOR SATURDAY...WITH MVFR POSSIBLE FARTHER EAST. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. .SHORT TERM...MODERATE TO HIGH CONFIDENCE. TONIGHT THROUGH TUESDAY... WINDS AND SEAS WILL REMAIN BELOW SMALL CRAFT ADVISORY LEVELS. HUMID AIR AND LIGHT FLOW WILL ALLOW FOR FOG THIS EVENING INTO THE OVERNIGHT HOURS WHICH SHOULD LIFT BY MIDDAY TOMORROW. THERE IS A LOW PROBABILITY FOR A CHANCE OF SHOWERS/TSTMS TOMORROW AS WELL. OUTLOOK...TUESDAY NIGHT THROUGH SATURDAY... MODERATE CONFIDENCE THROUGH THE PERIOD. THROUGH EARLY WEDNESDAY...CONDITIONS GENERALLY REMAIN BELOW SMALL CRAFT THRESHOLDS. SOME FOG MAY LEAD TO LOW VSBYS... PARTICULARLY LATE TUESDAY NIGHT. LATE WEDNESDAY INTO SATURDAY...A STRONGER LOW PRESSURE WILL PASS WELL NORTH AND WEST OF THE WATERS. HOWEVER...SOUTHWEST WINDS WILL INCREASE AND MAY REACH 25 KT AT TIMES. SEAS SHOULD BUILD THROUGH THIS PERIOD. THE BEST CHANCE FOR 5 FOOT PLUS SEAS WILL BE ACROSS THE OCEAN WATERS AND NEARSHORE WATERS SOUTH OF RI AND THE ISLANDS. SMALL CRAFT ADVISORIES MAY BE NEEDED. && .HYDROLOGY... ISOLATED TO SCATTERED THUNDERSTORMS STILL HAVE THE POTENTIAL TO DEVELOP. THERE ARE ALSO AREAS THAT HAVE HAD HEAVY DOWNPOURS RESULTING IN FLASH FLOODING OVER THE PAST FEW DAYS. PWAT VALUES WILL BE NEAR 1.7 TO 2 INCHES ABOVE NORMAL WHICH WILL RESULT IN SIGNIFICANT HEAVY DOWNPOURS. BOTH OF THESE REASONS PLAY INTO THE DECISION TO CONTINUE THE FLASH FLOOD WATCH. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...NONE. && $$ SYNOPSIS...BELK/DUNTEN NEAR TERM...DUNTEN SHORT TERM...DUNTEN LONG TERM...BELK AVIATION...BELK/DUNTEN MARINE...BELK/DUNTEN HYDROLOGY...
AREA FORECAST DISCUSSION...CORRECTED
NWS ALBANY NY
123 PM EDT SUN JUL 7 2013 .SYNOPSIS... THE BERMUDA HIGH WILL BEGIN TO WEAKEN AND MOVE A LITTLE FURTHER SOUTHEAST THROUGH THIS AFTERNOON. THIS WILL ALLOW MOISTURE TO MOVE BACK INTO THE REGION...INCREASING THE RISK OF SHOWERS AND THUNDERSTORMS. TONIGHT INTO MONDAY...AN UPPER LEVEL DISTURBANCE WILL MOVE BACK INTO FROM THE OHIO VALLEY...KEEPING OUR WEATHER UNSETTLED. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... SHOWERS AND THUNDERSTORMS ARE DEVELOPING WITH QUITE A BIT OF INSTABILITY OVER THE REGION. FREEZING LEVELS AND -20C LEVELS QUITE HIGH...BUT THERE COULD BE A STORM OR TWO THAT COULD PRODUCE SOME STRONG GUSTY WINDS...AND HEAVY RAIN IS ALWAYS A THREAT WITH LOCALIZED FLASH FLOODING. JUST SOME MINOR ADJUSTMENTS TO THE TEMPERATURES AND RAIN CHANCES THROUGH THIS AFTERNOON. THE LOCAL WRF AND HRRR SUGGEST AN ACTIVE AFTERNOON AND EVENING ACROSS THE REGION. HEAT INDICES IN THE MID HUDSON VALLEY AND NW CT WILL TOUCH 100 AT TIMES THIS AFTERNOON BUT NOT WIDESPREAD ENOUGH OR LONG ENOUGH DURATION FOR A SHORT FUSE HEAT ADVISORY. HEAT INDICES HAVE BEEN NEAR 100 THE PAST COUPLE OF AFTERNOONS AND HEAT INDICES A DEGREE OR TWO WARMER THIS AFTERNOON SHOULD FEEL NEARLY THE SAME AS THE PAST COUPLE OF AFTERNOONS. PREVIOUS DISCUSSION DESCRIBES THE FACTORS AFFECTING CONVECTION THIS AFTERNOON AND EVENING AND IS BELOW.. QUITE AN INSTABILITY GRADIENT HAS ALREADY SET UP ACROSS THE AREA...SINCE LOCATIONS TO THE SOUTH OF ALBANY DID NOT HAVE ANY CLOUDS/SHOWERS MOVE THROUGH EARLIER AND INSTEAD HAD SUNSHINE. COMBINED WITH A RETURN IN LOW LEVEL MOISTURE...THIS HAS ALLOW SBCAPE VALUES TO SURGE IN TO THE 2000-3000 J/KG RANGE LATE THIS MORNING. TO THE NORTH A RATHER SHARP INSTABILITY GRADIENT NOW EXISTS...ALTHOUGH IT WILL BECOME SOMEWHAT MORE UNIFORM BY EARLY AFTERNOON DUE TO PARTIAL SUNSHINE HEATING THIS AREA AS WELL. HOWEVER...THE INSTABILITY GRADIENT AND DIFFERENTIAL HEATING THAT OCCURRED MAY RESULT IN AN AREA TO WATCH FOR ENHANCED CONVECTION BY EARLY TO MID AFTERNOON. ANOTHER SOURCE OF ASCENT COULD BE A SUBTLE IMPULSE MOVING NORTHEASTWARD FROM THE UPPER LOW OVER THE OHIO VALLEY...THAT COULD TRACK THROUGH PA/NY THIS AFTERNOON AND EVENING. SO KEPT MENTION OF SCATTERED THUNDERSTORMS WITH RELATIVELY HIGH POPS OF 5O PERCENT. MESOSCALE MODELS SHOWING CONVECTION INITIATING ACROSS MUCH OF THE AREA THIS AFTERNOON...AND SOME STORMS COULD BE STRONG BASED ON HOW TALL UPDRAFTS ARE ABLE TO GET. DEEP LAYER SHEAR AROUND 25-35 KT IS SUFFICIENT FOR STORM ORGANIZATION...ALTHOUGH ONCE AGAIN MID LEVEL LAPSE RATES REMAIN RATHER MARGINAL AROUND 6.0 C/KM AND HIGH FREEZING LEVELS OVER 14 KFT. WITH MODERATE TO HIGH LEVELS OF INSTABILITY...WILL HAVE TO WATCH FOR WET MICROBURST POTENTIAL AND ONCE AGAIN HEAVY RAIN AND POSSIBLE ISOLATED FLASH FLOODING WITH THE STRONGER AND SLOW MOVING T-STORMS. && .SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/... WHILE THE AFOREMENTIONED DISTURBANCES WILL MOVE ON BY THIS EVENING...THE ACTUAL UPPER AIR LOW LOOKS TO MOVE OUR WAY LATE TONIGHT INTO MONDAY. THIS WILL SERVE TO COOL THE ATMOSPHERE A LITTLE BUT THE WIND FIELD (BULK SHEAR) LOOKS WEAK. SHOWERS AND STORMS LOOK TO DIMINISH IN AREA DURING THE EVENING...BUT COULD REKINDLE LATER OVERNIGHT INTO EARLY MONDAY. LOWS OVERNIGHT WILL BE MUGGY...65 TO 70 DEGREES. WE EXPECT PLENTY OF CLOUDS AROUND WITH THIS FEATURE INTO MONDAY WHICH DESPITE A SLIGHTLY COOLER MID LEVEL ATMOSPHERE...SHOULD ONCE AGAIN KEEP THUNDERSTORMS FROM THE MOST PART GETTING STRONG OR SEVERE. PWATS LOOK TO INCREASE SLIGHTLY...REACHING NEARLY 2 INCHES. THE BIGGER CONCERN WITH THE THUNDERSTORMS ON MONDAY WOULD BE THE POTENTIAL FOR EXCESSIVE RAINFALL. THERE THE POTENTIAL FOR SLOW MOVING THUNDERSTORMS TO PRODUCE RAINFALL EXCEEDING ONE-HOUR FLASH FLOOD GUIDANCE OF ONLY 1-2 INCHES ACROSS REGION. WHILE IT IS TOO EARLY TO ISSUE A FLASH FLOOD WATCH WE WILL CONTINUE TO HIGHLIGHT THIS POTENTIAL IN OUR HAZARDOUS WEATHER OUTLOOK PRODUCT. WITH THE CLOUDS AND EXPECTED SHOWERS AND STORMS ON MONDAY...TEMPERATURES WILL NOT BE AS HIGH AS THEY HAVE BEEN...TOPPING OUT 80-85 MOST VALLEY LOCATIONS...70S HIGHER TERRAIN. HOWEVER...IT WILL CERTAINLY REMAIN VERY HUMID. MONDAY NIGHT...LINGERING SHOWERS AND THUNDERSTORMS SHOULD DIMINISH AS THE UPPER AIR LOW OPENS AND FLEES TO THE EAST. PARTIAL CLEARING WILL ALLOW TEMPERATURES TO DIP A LITTLE LOWER...60 TO 65 DEGREES MOST PLACES...WITH A FEW UPPER 50S ACROSS THE ADIRONDACK PARK. TUESDAY...OPTIMISTICALLY LOOKS LIKE A MAINLY DRY DAY AS SLIGHTLY DRIER AIR WORKS INTO THE REGION VIA WEAK SUBSIDENCE. STILL...DECIDED TO ASSIGN SLIGHT POPS DURING THE AFTERNOON AS THERE WILL BE SOME INSTABILITY AND PRESUMABLY LOTS OF LOW LEVEL MOISTURE EVAPORATING FROM THE GROUND. SUNSHINE WILL RETURN TO HELP BOOST TEMPERATURES TO BETWEEN 85 AND 90 DEGREES IN MOST AREAS. IT LOOKS MAINLY DRY TUESDAY NIGHT...BUT BY WEDNESDAY...THE NEXT DISTURBANCE IN THE NORTHERN STREAM APPROACHES...BRINGING YET ANOTHER INCREASING THREAT IN SHOWERS AND THUNDERSTORMS. LOWS WILL GENERALLY BE IN THE 60S. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... THE PERIOD STARTS OUT WEDNESDAY WITH A WARM FRONT AND/OR PRE-FRONTAL TROUGH APPROACHING THE AREA FROM THE GREAT LAKES AND OHIO VALLEY. THIS SYSTEM WILL BRING SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS. THE EVENTUAL INTENSITY OF T-STORMS WILL DEPEND ON THE DEGREE OF INSTABILITY...WHICH WILL BE TIED TO CLOUD COVER. THERE SHOULD BE DECENT FLOW ALOFT FOR MID JULY WITH A MIGRATORY SUB-1000MB CYCLONE TRACKING EASTWARD ACROSS NEAR HUDSON BAY. THE ASSOCIATED COLD FRONT WILL PASS THROUGH THE REGION SOMETIME WEDNESDAY NIGHT...AND THEN BECOME NEARLY STATIONARY TO THE SOUTH OF THE REGION THURSDAY. POPS WILL BE FORECAST TO DECREASE FROM AROUND 50 PERCENT WEDNESDAY NIGHT...TO 30 TO 40 PERCENT ON THURSDAY. ONLY 20 PERCENT POPS ARE FORECAST THURSDAY NIGHT AND DRY WEATHER FOR FRIDAY AS THE UPPER LEVEL WAVE FORMS A CLOSED/CUTOFF LOW TO OUR SOUTHWEST...AND FOR A BRIEF TIME DRIER AIR MOVES INTO THE REGION. THE DRIER AIR WILL BE SHORT-LOVED AS THE UPPER LOW EVENTUALLY INDUCES THE MOISTURE ALONG THE FRONT TO SURGE NORTHWARD AGAIN FRIDAY NIGHT AND SATURDAY WITH A CHANCE OF SHOWERS. AFTER WEDNESDAY...TEMPERATURES AND HUMIDITY LEVELS WILL START TO DROP OFF SOMEWHAT AS A COOLER NORTHERLY FLOW DEVELOPS IN WAKE OF THE COLD FRONT. HIGHS WEDNESDAY WILL BE IN THE UPPER 70S AND 80S...IN THE MID 70S TO MID 80S THURSDAY...IN THE MID 70S TO LOWER 80S FRIDAY AND SATURDAY. LOWS WEDNESDAY NIGHT WILL BE IN THE MID 60S TO LOWER 70S...THE UPPER 50S AND 60S THURSDAY NIGHT...AND THE MID 50S TO MID 60S FRIDAY NIGHT. && .AVIATION /17Z SUNDAY THROUGH THURSDAY/... PREDOMINATELY VFR CONDITIONS WILL PREVAIL AT THE TAF SITES THIS AFTERNOON MINUS ANY SHOWER/THUNDERSTORM ASSOCIATED MVFR/IFR FLYING CONDITIONS. HAVE ONLY MENTIONED VCSH IN THE TAFS AT THIS TIME AS COVERAGE WILL REMAIN SCATTERED AT BEST AND WILL AMEND AS NEEDED. LATEST RADAR IMAGERY DEPICTS SCATTERED SHOWERS/THUNDERSTORMS DEVELOPING ACROSS THE REGION AND THESE WILL PERSIST THROUGH THE EVENING HOURS. ANY CONVECTION SHOULD DIMINISH BY MIDNIGHT WITH A BRIEF LULL IN PRECIPITATION AHEAD OF THE NEXT APPROACHING SYSTEM. INCREASING CLOUD COVER SHOULD LIMIT FOG POTENTIAL SOMEWHAT TONIGHT BUT WILL CONTINUE WITH MVFR FOG FOR ALL TAF SITES EXCEPT KALB. AN UPPER-LEVEL SHORTWAVE TROUGH AND SURFACE FRONTAL BOUNDARY WILL APPROACH THE REGION TONIGHT AND MONDAY BRINGING ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS TO THE TAF SITES TO END THE TAF PERIOD. SURFACE WINDS WILL BECOME SOUTH OR SOUTHWEST AT 5 TO 10 KTS...THEN BECOME LIGHT AGAIN AFTER SUNSET. OUTLOOK... TUE...MAINLY VFR. SCT -SHRA/-TSRA. WED...VFR/MVFR/IFR DUE TO SCT TO NUM -SHRA/-TSRA. THU-FRI...MAINLY VFR. SCT PM -SHRA/-TSRA. MVFR/IFR OVERNIGHT FOG POSSIBLE TUE-FRI. && .FIRE WEATHER... NO FIRE WEATHER ISSUES ARE EXPECTED OVER THE NEXT SEVERAL DAYS. AFTER A BRIEF BREAK IN THE ACTION ON SATURDAY...IT LOOKS AS IF SCATTERED SHOWERS AND THUNDERSTORMS RETURN TODAY AND AGAIN TOMORROW. SOME OF THESE ESPECIALLY ON MONDAY COULD PRODUCE LOCALLY HEAVY RAINFALL. TUESDAY LOOKS DRIER BUT THEN MORE SHOWERS COULD TAKE PLACE ON WEDNESDAY. NORMAL RH RECOVERIES EACH NIGHT BETWEEN 80 TO 100 PERCENT WILL ALLOW FOR WIDESPREAD DEW FORMATION. DAYTIME RH VALUES WILL GENERALLY BE IN THE 40 TO 60 PERCENT RANGE. && .HYDROLOGY... THE MOHAWK RIVER AT UTICA CONTINUES TO EXPERIENCE MINOR FLOODING. THE RIVER AND CREEK FLOWS NEAR THE WEST CENTRAL MOHAWK RIVER ARE EXPECTED TO GRADUALLY RECEDE INTO THE WEEKEND...UNLESS ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS OCCUR OVER OR NEAR THE BASIN. THERE WILL BE SCATTERED SHOWERS AND THUNDERSTORMS...MAINLY DURING THE AFTERNOON AND EVEN MORE COVERAGE OF SHOWERS AND THUNDERSTORMS MONDAY WITH THE APPROACH OF A WEAK COLD FRONT AND UPPER AIR LOW PRESSURE SYSTEM. A MOIST AND HUMID AIR MASS WILL ALLOW ANY SHOWER OR THUNDERSTORM TO BE CAPABLE OF PRODUCING LOCALLY HEAVY DOWNPOURS...AND A QUICK INCH OR MORE OF RAINFALL DUE TO THE ANOMALOUS PRECIPITABLE WATER VALUES...ESPECIALLY ON MONDAY. THERE WILL BE A CONTINUED THREAT FOR ISOLATED FLASH FLOODING...AS WELL AS FLOODING OF POOR DRAINAGE AND LOW LYING AREAS. NO FLASH FLOOD WATCHES ARE BEING ISSUED DUE TO THE EXPECTED ISOLATED NATURE OF ANY FLOODING. IT IS ALSO DIFFICULT TO DETERMINE WHERE THE HEAVIEST RAINFALL WILL OCCUR. WHILE ADDITIONAL FLOODING IS NOT ANTICIPATED ON ANY MAIN STEM RIVER POINTS...LOCALLY SHARP RISES ARE POSSIBLE DUE TO ANY CONVECTION THAT MAY OCCUR OVER THE NEXT SEVERAL DAYS...ESPECIALLY FOR THOSE POINTS THAT ARE MORE FLASHIER IN NATURE. FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. MA...NONE. VT...NONE. && $$ SYNOPSIS...HWJIV/NAS NEAR TERM...HWJIV/NAS SHORT TERM...HWJIV LONG TERM...GJM AVIATION...IRL FIRE WEATHER...HWJIV HYDROLOGY...NAS
AREA FORECAST DISCUSSION
NWS ALBANY NY
122 PM EDT SUN JUL 7 2013 .SYNOPSIS... THE BERMUDA HIGH WILL BEGIN TO WEAKEN AND MOVE A LITTLE FURTHER SOUTHEAST THROUGH THIS AFTERNOON. THIS WILL ALLOW MOISTURE TO MOVE BACK INTO THE REGION...INCREASING THE RISK OF SHOWERS AND THUNDERSTORMS. TONIGHT INTO MONDAY...AN UPPER LEVEL DISTURBANCE WILL MOVE BACK INTO FROM THE OHIO VALLEY...KEEPING OUR WEATHER UNSETTLED. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... SHOWERS AND THUNDERSTORMS ARE DEVELOPING WITH QUITE A BIT OF INSTABILITY OVER THE REGION. FREEZING LEVELS ADN -20C LEVELS QUITE HIGH...BUT THERE COULD BE A STORM OR TWO THAT COULD PRODUCE SOME STRONG GUSTY WINDS...AND HEAVY RAIN IS ALWAYS A THREAT WITH LOCALIZED FLASH FLOODING. JUST SOME MINOR ADJUSTMENTS TO THE TEMPERATURES AND RAIN CHANCES THROUGH THIS AFTERNOON. THE LOCAL WRF AND HRRR SUGGEST AN ACTIVE AFTERNOON AND EVENING ACROSS THE REGION. HEAT INDICES IN THE MID HUDSON VALLEY AND NW CT WILL TOUCH 100 AT TIMES THIS AFTERNOON BUT NOT WIDESPREAD ENOUGH OR LONG ENOUGH DURATION FOR A SHORT FUSE HEAT ADVISORY. HEAT INDICES HAVE BEEN NEAR 100 THE PAST COUPLE OF AFTERNOONS AND HEAT INDICES A DEGREE OR TWO WARMER THIS AFTERNOON SHOULD FEEL NEARLY THE SAME AS THE PAST COUPLE OF AFTERNOONS. PREVIOUS DISCUSSION DESCRIBES THE FACTORS AFFECTING CONVECTION THIS AFTERNOON AND EVENING AND IS BELOW.. QUITE AN INSTABILITY GRADIENT HAS ALREADY SET UP ACROSS THE AREA...SINCE LOCATIONS TO THE SOUTH OF ALBANY DID NOT HAVE ANY CLOUDS/SHOWERS MOVE THROUGH EARLIER AND INSTEAD HAD SUNSHINE. COMBINED WITH A RETURN IN LOW LEVEL MOISTURE...THIS HAS ALLOW SBCAPE VALUES TO SURGE IN TO THE 2000-3000 J/KG RANGE LATE THIS MORNING. TO THE NORTH A RATHER SHARP INSTABILITY GRADIENT NOW EXISTS...ALTHOUGH IT WILL BECOME SOMEWHAT MORE UNIFORM BY EARLY AFTERNOON DUE TO PARTIAL SUNSHINE HEATING THIS AREA AS WELL. HOWEVER...THE INSTABILITY GRADIENT AND DIFFERENTIAL HEATING THAT OCCURRED MAY RESULT IN AN AREA TO WATCH FOR ENHANCED CONVECTION BY EARLY TO MID AFTERNOON. ANOTHER SOURCE OF ASCENT COULD BE A SUBTLE IMPULSE MOVING NORTHEASTWARD FROM THE UPPER LOW OVER THE OHIO VALLEY...THAT COULD TRACK THROUGH PA/NY THIS AFTERNOON AND EVENING. SO KEPT MENTION OF SCATTERED THUNDERSTORMS WITH RELATIVELY HIGH POPS OF 5O PERCENT. MESOSCALE MODELS SHOWING CONVECTION INITIATING ACROSS MUCH OF THE AREA THIS AFTERNOON...AND SOME STORMS COULD BE STRONG BASED ON HOW TALL UPDRAFTS ARE ABLE TO GET. DEEP LAYER SHEAR AROUND 25-35 KT IS SUFFICIENT FOR STORM ORGANIZATION...ALTHOUGH ONCE AGAIN MID LEVEL LAPSE RATES REMAIN RATHER MARGINAL AROUND 6.0 C/KM AND HIGH FREEZING LEVELS OVER 14 KFT. WITH MODERATE TO HIGH LEVELS OF INSTABILITY...WILL HAVE TO WATCH FOR WET MICROBURST POTENTIAL AND ONCE AGAIN HEAVY RAIN AND POSSIBLE ISOLATED FLASH FLOODING WITH THE STRONGER AND SLOW MOVING T-STORMS. && .SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/... WHILE THE AFOREMENTIONED DISTURBANCES WILL MOVE ON BY THIS EVENING...THE ACTUAL UPPER AIR LOW LOOKS TO MOVE OUR WAY LATE TONIGHT INTO MONDAY. THIS WILL SERVE TO COOL THE ATMOSPHERE A LITTLE BUT THE WIND FIELD (BULK SHEAR) LOOKS WEAK. SHOWERS AND STORMS LOOK TO DIMINISH IN AREA DURING THE EVENING...BUT COULD REKINDLE LATER OVERNIGHT INTO EARLY MONDAY. LOWS OVERNIGHT WILL BE MUGGY...65 TO 70 DEGREES. WE EXPECT PLENTY OF CLOUDS AROUND WITH THIS FEATURE INTO MONDAY WHICH DESPITE A SLIGHTLY COOLER MID LEVEL ATMOSPHERE...SHOULD ONCE AGAIN KEEP THUNDERSTORMS FROM THE MOST PART GETTING STRONG OR SEVERE. PWATS LOOK TO INCREASE SLIGHTLY...REACHING NEARLY 2 INCHES. THE BIGGER CONCERN WITH THE THUNDERSTORMS ON MONDAY WOULD BE THE POTENTIAL FOR EXCESSIVE RAINFALL. THERE THE POTENTIAL FOR SLOW MOVING THUNDERSTORMS TO PRODUCE RAINFALL EXCEEDING ONE-HOUR FLASH FLOOD GUIDANCE OF ONLY 1-2 INCHES ACROSS REGION. WHILE IT IS TOO EARLY TO ISSUE A FLASH FLOOD WATCH WE WILL CONTINUE TO HIGHLIGHT THIS POTENTIAL IN OUR HAZARDOUS WEATHER OUTLOOK PRODUCT. WITH THE CLOUDS AND EXPECTED SHOWERS AND STORMS ON MONDAY...TEMPERATURES WILL NOT BE AS HIGH AS THEY HAVE BEEN...TOPPING OUT 80-85 MOST VALLEY LOCATIONS...70S HIGHER TERRAIN. HOWEVER...IT WILL CERTAINLY REMAIN VERY HUMID. MONDAY NIGHT...LINGERING SHOWERS AND THUNDERSTORMS SHOULD DIMINISH AS THE UPPER AIR LOW OPENS AND FLEES TO THE EAST. PARTIAL CLEARING WILL ALLOW TEMPERATURES TO DIP A LITTLE LOWER...60 TO 65 DEGREES MOST PLACES...WITH A FEW UPPER 50S ACROSS THE ADIRONDACK PARK. TUESDAY...OPTIMISTICALLY LOOKS LIKE A MAINLY DRY DAY AS SLIGHTLY DRIER AIR WORKS INTO THE REGION VIA WEAK SUBSIDENCE. STILL...DECIDED TO ASSIGN SLIGHT POPS DURING THE AFTERNOON AS THERE WILL BE SOME INSTABILITY AND PRESUMABLY LOTS OF LOW LEVEL MOISTURE EVAPORATING FROM THE GROUND. SUNSHINE WILL RETURN TO HELP BOOST TEMPERATURES TO BETWEEN 85 AND 90 DEGREES IN MOST AREAS. IT LOOKS MAINLY DRY TUESDAY NIGHT...BUT BY WEDNESDAY...THE NEXT DISTURBANCE IN THE NORTHERN STREAM APPROACHES...BRINGING YET ANOTHER INCREASING THREAT IN SHOWERS AND THUNDERSTORMS. LOWS WILL GENERALLY BE IN THE 60S. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... THE PERIOD STARTS OUT WEDNESDAY WITH A WARM FRONT AND/OR PRE-FRONTAL TROUGH APPROACHING THE AREA FROM THE GREAT LAKES AND OHIO VALLEY. THIS SYSTEM WILL BRING SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS. THE EVENTUAL INTENSITY OF T-STORMS WILL DEPEND ON THE DEGREE OF INSTABILITY...WHICH WILL BE TIED TO CLOUD COVER. THERE SHOULD BE DECENT FLOW ALOFT FOR MID JULY WITH A MIGRATORY SUB-1000MB CYCLONE TRACKING EASTWARD ACROSS NEAR HUDSON BAY. THE ASSOCIATED COLD FRONT WILL PASS THROUGH THE REGION SOMETIME WEDNESDAY NIGHT...AND THEN BECOME NEARLY STATIONARY TO THE SOUTH OF THE REGION THURSDAY. POPS WILL BE FORECAST TO DECREASE FROM AROUND 50 PERCENT WEDNESDAY NIGHT...TO 30 TO 40 PERCENT ON THURSDAY. ONLY 20 PERCENT POPS ARE FORECAST THURSDAY NIGHT AND DRY WEATHER FOR FRIDAY AS THE UPPER LEVEL WAVE FORMS A CLOSED/CUTOFF LOW TO OUR SOUTHWEST...AND FOR A BRIEF TIME DRIER AIR MOVES INTO THE REGION. THE DRIER AIR WILL BE SHORT-LOVED AS THE UPPER LOW EVENTUALLY INDUCES THE MOISTURE ALONG THE FRONT TO SURGE NORTHWARD AGAIN FRIDAY NIGHT AND SATURDAY WITH A CHANCE OF SHOWERS. AFTER WEDNESDAY...TEMPERATURES AND HUMIDITY LEVELS WILL START TO DROP OFF SOMEWHAT AS A COOLER NORTHERLY FLOW DEVELOPS IN WAKE OF THE COLD FRONT. HIGHS WEDNESDAY WILL BE IN THE UPPER 70S AND 80S...IN THE MID 70S TO MID 80S THURSDAY...IN THE MID 70S TO LOWER 80S FRIDAY AND SATURDAY. LOWS WEDNESDAY NIGHT WILL BE IN THE MID 60S TO LOWER 70S...THE UPPER 50S AND 60S THURSDAY NIGHT...AND THE MID 50S TO MID 60S FRIDAY NIGHT. && .AVIATION /17Z SUNDAY THROUGH THURSDAY/... PREDOMINATELY VFR CONDITIONS WILL PREVAIL AT THE TAF SITES THIS AFTERNOON MINUS ANY SHOWER/THUNDERSTORM ASSOCIATED MVFR/IFR FLYING CONDITIONS. HAVE ONLY MENTIONED VCSH IN THE TAFS AT THIS TIME AS COVERAGE WILL REMAIN SCATTERED AT BEST AND WILL AMEND AS NEEDED. LATEST RADAR IMAGERY DEPICTS SCATTERED SHOWERS/THUNDERSTORMS DEVELOPING ACROSS THE REGION AND THESE WILL PERSIST THROUGH THE EVENING HOURS. ANY CONVECTION SHOULD DIMINISH BY MIDNIGHT WITH A BRIEF LULL IN PRECIPITATION AHEAD OF THE NEXT APPROACHING SYSTEM. INCREASING CLOUD COVER SHOULD LIMIT FOG POTENTIAL SOMEWHAT TONIGHT BUT WILL CONTINUE WITH MVFR FOG FOR ALL TAF SITES EXCEPT KALB. AN UPPER-LEVEL SHORTWAVE TROUGH AND SURFACE FRONTAL BOUNDARY WILL APPROACH THE REGION TONIGHT AND MONDAY BRINGING ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS TO THE TAF SITES TO END THE TAF PERIOD. SURFACE WINDS WILL BECOME SOUTH OR SOUTHWEST AT 5 TO 10 KTS...THEN BECOME LIGHT AGAIN AFTER SUNSET. OUTLOOK... TUE...MAINLY VFR. SCT -SHRA/-TSRA. WED...VFR/MVFR/IFR DUE TO SCT TO NUM -SHRA/-TSRA. THU-FRI...MAINLY VFR. SCT PM -SHRA/-TSRA. MVFR/IFR OVERNIGHT FOG POSSIBLE TUE-FRI. && .FIRE WEATHER... NO FIRE WEATHER ISSUES ARE EXPECTED OVER THE NEXT SEVERAL DAYS. AFTER A BRIEF BREAK IN THE ACTION ON SATURDAY...IT LOOKS AS IF SCATTERED SHOWERS AND THUNDERSTORMS RETURN TODAY AND AGAIN TOMORROW. SOME OF THESE ESPECIALLY ON MONDAY COULD PRODUCE LOCALLY HEAVY RAINFALL. TUESDAY LOOKS DRIER BUT THEN MORE SHOWERS COULD TAKE PLACE ON WEDNESDAY. NORMAL RH RECOVERIES EACH NIGHT BETWEEN 80 TO 100 PERCENT WILL ALLOW FOR WIDESPREAD DEW FORMATION. DAYTIME RH VALUES WILL GENERALLY BE IN THE 40 TO 60 PERCENT RANGE. && .HYDROLOGY... THE MOHAWK RIVER AT UTICA CONTINUES TO EXPERIENCE MINOR FLOODING. THE RIVER AND CREEK FLOWS NEAR THE WEST CENTRAL MOHAWK RIVER ARE EXPECTED TO GRADUALLY RECEDE INTO THE WEEKEND...UNLESS ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS OCCUR OVER OR NEAR THE BASIN. THERE WILL BE SCATTERED SHOWERS AND THUNDERSTORMS...MAINLY DURING THE AFTERNOON AND EVEN MORE COVERAGE OF SHOWERS AND THUNDERSTORMS MONDAY WITH THE APPROACH OF A WEAK COLD FRONT AND UPPER AIR LOW PRESSURE SYSTEM. A MOIST AND HUMID AIR MASS WILL ALLOW ANY SHOWER OR THUNDERSTORM TO BE CAPABLE OF PRODUCING LOCALLY HEAVY DOWNPOURS...AND A QUICK INCH OR MORE OF RAINFALL DUE TO THE ANOMALOUS PRECIPITABLE WATER VALUES...ESPECIALLY ON MONDAY. THERE WILL BE A CONTINUED THREAT FOR ISOLATED FLASH FLOODING...AS WELL AS FLOODING OF POOR DRAINAGE AND LOW LYING AREAS. NO FLASH FLOOD WATCHES ARE BEING ISSUED DUE TO THE EXPECTED ISOLATED NATURE OF ANY FLOODING. IT IS ALSO DIFFICULT TO DETERMINE WHERE THE HEAVIEST RAINFALL WILL OCCUR. WHILE ADDITIONAL FLOODING IS NOT ANTICIPATED ON ANY MAIN STEM RIVER POINTS...LOCALLY SHARP RISES ARE POSSIBLE DUE TO ANY CONVECTION THAT MAY OCCUR OVER THE NEXT SEVERAL DAYS...ESPECIALLY FOR THOSE POINTS THAT ARE MORE FLASHIER IN NATURE. FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. MA...NONE. VT...NONE. && $$ SYNOPSIS...HWJIV/NAS NEAR TERM...HWJIV/NAS SHORT TERM...HWJIV LONG TERM...GJM AVIATION...IRL FIRE WEATHER...HWJIV HYDROLOGY...NAS
AREA FORECAST DISCUSSION
NWS ALBANY NY
210 AM EDT SUN JUL 7 2013 .SYNOPSIS... THE BERMUDA HIGH WILL BEGIN TO WEAKEN AND MOVE A LITTLE FURTHER SOUTHEAST TODAY. THIS WILL ALLOW MOISTURE TO MOVE BACK INTO THE REGION ON SUNDAY...INCREASING THE RISK OF SHOWERS AND THUNDERSTORMS. SUNDAY NIGHT INTO MONDAY...AN UPPER LEVEL DISTURBANCE WILL MOVE BACK INTO FROM THE OHIO VALLEY...KEEPING OUR WEATHER UNSETTLED. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... AS OF 1240 PM EDT...ALL STILL QUITE ON OUR RADAR. A MOSTLY CLEAR SKY ALLOWING TEMPERATURES TO FALL A LITTLE DOWN INTO THE 70S IN THE URBAN AREAS...60S OUTLYING REGION. NO FOG YET...BUT WITH TEMPERATURES CLOSING TOWARD THE DEWPOINT IN SOME CASES...SOME PATCHY FOG LOOKS LIKELY TOWARD DAYBREAK. THERE ARE A FEW SHOWERS UPSTREAM ACROSS SOUTH CENTRAL NEW YORK STATE...SLOWLY HEADING THIS WAY. ONE OF OUR EXPERIMENTAL NEAR TERM MODELS THE HRRR INDICATED THESE WOULD COME INTO THE OUR REGION BEFORE SUNRISE...PASSING THE CAPITAL REGION AFTER 800 AM AS HEAVY SHOWERS POSSIBLY EVEN A THUNDERSTORM. NOT SEEING IT THOUGH AS INSTABILITY IS LIMITED FROM THE CAPITAL REGION NORTHWARD...ALTHOUGH SOME REMAINS TO OUR SOUTH (UP TO 1000 J/KG OFF THE LAPS). WITH HIGH PRESSURE IN PLACE...BELIEVE THE SHOWERS WILL INITIALLY HAVE A HARD TIME HEADING OUR WAY...AT LEAST THROUGH THE OVERNIGHT. WILL KEEP POPS BELOW 15 PERCENT...ESSENTIALLY DRY. HOWEVER...WILL CONTINUE TO INTRODUCE SLIGHT POPS AFTER SUNRISE AND SPREAD THEM EASTWARD WITH TIME. UPDATED TEMPS/DEW POINTS/CLOUDS TO REFLECT CURRENT OBS. OTHERWISE...NO ADDITIONAL CHANGES. WITH THE LIGHT WINDS AND HUMIDITY...TEMPERATURES SHOULD NOT COOL OFF TOO MUCH FROM HOT EVENING TEMPERATURES DUE TO THE SHORT NIGHTS THIS TIME OF YEAR...EVEN WITH THE PARTLY CLOUDY TO CLEAR SKY. SOME PATCHY FOG IS ALSO POSSIBLE IN SOME AREAS. LOWS SHOULD BE IN THE 60S TO AROUND 70...WHICH IS A LITTLE COOLER THAN LAST NIGHT. && .SHORT TERM /6 AM THIS MORNING THROUGH TUESDAY/... UPPER ENERGY IN THE MIDWEST AND OH VALLEY SHOULD MOVE STEADILY EAST AND THERE IS A GOOD CONSENSUS THAT ONE UPPER IMPULSE AT THE LEADING EDGE OF THIS UPPER ENERGY SHOULD TRACK ACROSS THE REGION TOMORROW AFTERNOON. THIS UPPER ENERGY SHOULD SUPPORT BETTER COVERAGE OF SHOWERS AND THUNDERSTORMS TOMORROW AFTERNOON AND EVENING OVER EASTERN NY INTO THE NORTHERN BERKSHIRES AND SOUTHERN VT. ACTIVITY COULD BE LIMITED IN THE MID HUDSON VALLEY AND NW CT SINCE THE UPPER ENERGY IS PREDICTED TO TRACK THROUGH MAINLY NORTHERN AND CENTRAL AREAS. HIGHS SUNDAY IN THE 80S TO LOWER 90S...WITH THE WARMEST TEMPERATURES IN THE MID HUDSON VALLEY AND NW CT. THE MAIN CENTER OF THE UPPER ENERGY TRACKS JUST SOUTH OF THE REGION MONDAY AND MONDAY AFTERNOON...BUT LOW LEVEL FORCING WITH A LITTLE BIT OF COOLING AT THE BOUNDARY LAYER AND THE UPPER DYNAMICS SHOULD SUPPORT INCREASED COVERAGE OF CLOUDS...SHOWERS AND THUNDERSTORMS. HIGHS MONDAY SHOULD BE IN THE MID 80S...NEAR 80 IN THE SOUTHERN ADIRONDACKS AND UPPER 80S MID HUDSON VALLEY AND NW CT. LOCALLY HEAVY RAIN BOTH SUNDAY AND MONDAY COULD RESULT IN LOCALIZED FLASH FLOODING AND A WATCH COULD BE CONSIDERED OVERNIGHT OR TOMORROW DEPENDING ON HOW MUCH COVERAGE OF SHOWERS AND THUNDERSTORMS COULD BE EXPECTED...SO STAY TUNED. THERE ARE INDICATIONS THAT THE UPPER ENERGY AND WEAK COLD FRONT EXIT THE REGION MONDAY NIGHT...WITH SOME POTENTIAL PARTIAL CLEARING OUTSIDE OF AREAS OF FOG BY EARLY TUESDAY MORNING. LOWS SHOULD BE IN THE 60S...WITH MAYBE SOME MID TO UPPER 50S IN THE SOUTHERN ADIRONDACKS. ON TUESDAY...SOME WEAK UPPER RIDGING SHOULD BE OVER THE REGION...BUT THE ATMOSPHERE SHOULD STILL BE UNSTABLE... EVEN WITH NO REAL ORGANIZED LOW LEVEL FOCUS. SO...THERE COULD BE ISOLATED SHOWERS AND THUNDERSTORMS IN THE SOUTHERN HALF OF THE FORECAST AREA WITH HIGHS IN THE 80S. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... THE PERIOD STARTS OUT LATE TUESDAY NIGHT INTO WEDNESDAY WITH A WARM FRONT AND/OR PRE-FRONTAL TROUGH APPROACHING THE AREA FROM THE GREAT LAKES AND OHIO VALLEY. THIS SYSTEM WILL BRING ADDITIONAL CHANCES FOR AT LEAST SCATTERED SHOWERS AND THUNDERSTORMS. THE EVENTUAL INTENSITY OF T-STORMS WILL DEPEND ON THE DEGREE OF INSTABILITY...WHICH WILL BE TIED TO CLOUD COVER. THERE SHOULD BE DECENT FLOW ALOFT FOR MID JULY WITH A MIGRATORY SUB-1000MB CYCLONE TRACKING EASTWARD NEAR HUDSON BAY. THE FIRST SERIES OF FRONTAL BOUNDARY WILL PASS THROUGH BY SOMETIME LATE WEDNESDAY OR WEDNESDAY NIGHT...WHILE THE MAIN COLD FRONT IS FORECAST TO SAG SOUTHWARD ACROSS THE AREA LATE WEDNESDAY NIGHT INTO THURSDAY. WILL CONTINUE TO MENTION CHANCE POPS DURING THIS TIME...WITH THE POSSIBLY MORE ROBUST CONVECTION OCCURRING ON WEDNESDAY. THERE COULD BE AN ADDITIONAL ROUND OF T-STORMS SOUTH OF ALBANY ON THURSDAY IF THE FRONT SLOWS ENOUGH...WHICH IS BEING DEPICTED BY THE 12Z GFS AND ECMWF. IT AT LEAST LOOKS LIKE TEMPERATURES AND HUMIDITY LEVELS WILL START TO SOMEWHAT DROP BY WEEK`S END AS A COOLER NORTHERLY FLOW DEVELOPS IN WAKE OF THE COLD FRONT. HOWEVER...THE CHAOTIC UPPER LEVEL PATTERN MAY ALLOW FOR A CUT-OFF LOW TO FORM SOMEWHAT IN THE VICINITY OF THE OHIO VALLEY...MID ATLANTIC...OR SOUTHERN APPALACHIANS REGION WHICH COULD RESULT IN A MOIST SOUTHERLY FLOW QUICKLY RETURNING BY THE WEEKEND ALONG WITH RENEWED CHANCES FOR PRECIP AND INCREASING HUMIDITY. THERE STILL CONSIDERABLE UNCERTAINTY IN HOW THE PATTERN WILL EVENTUALLY UNFOLD...BUT BOTH THE GFS AND ECMWF ARE DEPICTING A CUT-OFF LOW FORMING SOUTH AND WEST OF OUR AREA NEXT WEEKEND. && .AVIATION /12Z SUNDAY THROUGH THURSDAY/... AS OF 06Z KGFL/KPOU HAD ALREADY HAD OCCASIONAL IFR VSBYS DUE TO FOG...WHILE NO FOG HAD BEEN REPORTED AT KALB/KPSF. STLT PICS SHOW A WIDESPREAD CLOUD DECK (GENERALLY MID/HI CLOUDS) MOVING OVER THE TAF SITES AS OF 06Z AND WOULD EXPECT THIS CLOUD DECK TO INHIBIT FOG FORMATION IF FOG HAD NOT LREADY FORMED BEFORE IT ARRIVES. WILL CONTINUE TO FORECAST OCNL IFR FOG AT KGFL/KPOU THROUGH 11Z...BUT FORECAST NO FOG AT KALB AND ONLY OCCASIONAL MVFR FOG AT KPSF. THERE ARE SCT TO NUMEROUS SHWRS/TSTMS OVER FAR WESTERN NEW YORK AS OF 06Z...WITH ISOLATED SHOWERS FURTHER EAST. THESE SHOWERS ARE ASSOCIATED WITH AN APPROACHING UPPER LEVEL TROF. WOULD NOT EXPECT THESE SHOWERS TO BE NEAR THE TAF SITES BEFORE MID OR LATE SUNDAY MORNING. MODEL FORECASTS AND OBSERVED MOVEMENT OF THESE SHWRS/TSTMS WOULD SUGGEST THE BULK OF THEM WILL PASS TO THE NORTH AND WEST OF THE TAF SITES. AS A RESULT...WILL FORECAST NO MORE THAN VCSH IN THE TAFS FROM LATE THIS MORNING THROUGH THE END OF THE TAF PERIOD AT 06Z MONDAY. ALSO...EXCEPT FOR THE EARLY MORNING FOG CONDITIONS...HAVE FORECAST VFR CONDITIONS AT THE TAF SITES THROUGH THE END OF THE TAF PERIOD. SURFACE WIND WILL GENERALLY BE CALM THROUGH 2 TO 3 HOURS AFTER SUNRISE...THEN BECOME SOUTH OR SOUTHWEST AT 5 TO 10 KTS...THEN BECOME LIGHT AGAIN AFTER SUNSET ON SUNDAY. OUTLOOK... LATE SUN NITE-TUE...MAINLY VFR. SCT MAINLY AFTERNOON AND EVENING SHRA/TSRA. POSSIBLE LATE NIGHT AND/OR EARLY MORNING FOG/LOW STRATUS WITH MVFR/IFR POSSIBLE. WED...VFR/MVFR/IFR DUE TO SCT TO NUMEROUS SHRA/TSRA. && .FIRE WEATHER... NO FIRE WEATHER ISSUES ARE EXPECTED OVER THE NEXT SEVERAL DAYS. FUELS CONTINUE TO REMAIN SATURATED FROM RECENT SHOWER/THUNDERSTORM ACTIVITY. THERE WILL CONTINUE TO BE A CHANCE FOR AFTERNOON/EVENING SHOWERS AND THUNDERSTORMS FOR THE NEXT SEVERAL DAYS AS THE BERMUDA HIGH KEEPS A HOT AND HUMID AIR MASS ENTRENCHED OVER THE REGION. NORMAL RH RECOVERIES EACH NIGHT BETWEEN 80 TO 100 PERCENT WILL ALLOW FOR WIDESPREAD DEW FORMATION. DAYTIME RH VALUES WILL GENERALLY BE IN THE 40 TO 60 PERCENT RANGE. && .HYDROLOGY... THE MOHAWK RIVER AT UTICA CONTINUES TO EXPERIENCE MINOR FLOODING. THE RIVER AND CREEK FLOWS NEAR THE WEST CENTRAL MOHAWK RIVER ARE EXPECTED TO GRADUALLY RECEDE INTO THE WEEKEND...UNLESS ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS OCCUR OVER OR NEAR THE BASIN. THERE COULD BE SCATTERED SHOWERS AND THUNDERSTORMS SUNDAY AFTERNOON AND EVEN MORE COVERAGE OF SHOWERS AND THUNDERSTORMS MONDAY AFTERNOON AND EVENING WITH THE APPROACH OF A WEAK COLD FRONT. A MOIST AND HUMID AIR MASS WILL ALLOW ANY SHOWER OR THUNDERSTORM TO BE CAPABLE OF PRODUCING LOCALLY HEAVY DOWNPOURS...AND A QUICK INCH OR MORE OF RAINFALL DUE TO THE ANOMALOUS PRECIPITABLE WATER VALUES. THERE WILL BE A CONTINUED THREAT FOR ISOLATED FLASH FLOODING...AS WELL AS FLOODING OF POOR DRAINAGE AND LOW LYING AREAS. NO FLASH FLOOD WATCHES ARE BEING ISSUED DUE TO THE EXPECTED ISOLATED NATURE OF ANY FLOODING. IT IS ALSO DIFFICULT TO DETERMINE WHERE THE HEAVIEST RAINFALL WILL OCCUR. WHILE ADDITIONAL FLOODING IS NOT ANTICIPATED ON ANY MAIN STEM RIVER POINTS...LOCALLY SHARP RISES ARE POSSIBLE DUE TO ANY CONVECTION THAT MAY OCCUR OVER THE NEXT SEVERAL DAYS...ESPECIALLY FOR THOSE POINTS THAT ARE MORE FLASHIER IN NATURE. FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. MA...NONE. VT...NONE. && $$ SYNOPSIS...HWJIV NEAR TERM...HWJIV/OKEEFE SHORT TERM...NAS LONG TERM...JPV AVIATION...GJM FIRE WEATHER...NAS HYDROLOGY...NAS
AREA FORECAST DISCUSSION
NWS ALBANY NY
1237 AM EDT SUN JUL 7 2013 .SYNOPSIS... THE BERMUDA HIGH WILL BEGIN TO WEAKEN AND MOVE A LITTLE FURTHER SOUTHEAST TODAY. THIS WILL ALLOW MOISTURE TO MOVE BACK INTO THE REGION ON SUNDAY...INCREASING THE RISK OF SHOWERS AND THUNDERSTORMS. SUNDAY NIGHT INTO MONDAY...AN UPPER LEVEL DISTURBANCE WILL MOVE BACK INTO FROM THE OHIO VALLEY...KEEPING OUR WEATHER UNSETTLED. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... AS OF 1240 PM EDT...ALL STILL QUITE ON OUR RADAR. A MOSTLY CLEAR SKY ALLOWING TEMPERATURES TO FALL A LITTLE DOWN INTO THE 70S IN THE URBAN AREAS...60S OUTLYING REGION. NO FOG YET...BUT WITH TEMPERATURES CLOSING TOWARD THE DEWPOINT IN SOME CASES...SOME PATCHY FOG LOOKS LIKELY TOWARD DAYBREAK. THERE ARE A FEW SHOWERS UPSTREAM ACROSS SOUTH CENTRAL NEW YORK STATE...SLOWLY HEADING THIS WAY. ONE OF OUR EXPERIMENTAL NEAR TERM MODELS THE HRRR INDICATED THESE WOULD COME INTO THE OUR REGION BEFORE SUNRISE...PASSING THE CAPITAL REGION AFTER 800 AM AS HEAVY SHOWERS POSSIBLY EVEN A THUNDERSTORM. NOT SEEING IT THOUGH AS INSTABILITY IS LIMITED FROM THE CAPITAL REGION NORTHWARD...ALTHOUGH SOME REMAINS TO OUR SOUTH (UP TO 1000 J/KG OFF THE LAPS). WITH HIGH PRESSURE IN PLACE...BELIEVE THE SHOWERS WILL INITIALLY HAVE A HARD TIME HEADING OUR WAY...AT LEAST THROUGH THE OVERNIGHT. WILL KEEP POPS BELOW 15 PERCENT...ESSENTIALLY DRY. HOWEVER...WILL CONTINUE TO INTRODUCE SLIGHT POPS AFTER SUNRISE AND SPREAD THEM EASTWARD WITH TIME. UPDATED TEMPS/DEW POINTS/CLOUDS TO REFLECT CURRENT OBS. OTHERWISE...NO ADDITIONAL CHANGES. WITH THE LIGHT WINDS AND HUMIDITY...TEMPERATURES SHOULD NOT COOL OFF TOO MUCH FROM HOT EVENING TEMPERATURES DUE TO THE SHORT NIGHTS THIS TIME OF YEAR...EVEN WITH THE PARTLY CLOUDY TO CLEAR SKY. SOME PATCHY FOG IS ALSO POSSIBLE IN SOME AREAS. LOWS SHOULD BE IN THE 60S TO AROUND 70...WHICH IS A LITTLE COOLER THAN LAST NIGHT. && .SHORT TERM /6 AM THIS MORNING THROUGH TUESDAY/... UPPER ENERGY IN THE MIDWEST AND OH VALLEY SHOULD MOVE STEADILY EAST AND THERE IS A GOOD CONSENSUS THAT ONE UPPER IMPULSE AT THE LEADING EDGE OF THIS UPPER ENERGY SHOULD TRACK ACROSS THE REGION TOMORROW AFTERNOON. THIS UPPER ENERGY SHOULD SUPPORT BETTER COVERAGE OF SHOWERS AND THUNDERSTORMS TOMORROW AFTERNOON AND EVENING OVER EASTERN NY INTO THE NORTHERN BERKSHIRES AND SOUTHERN VT. ACTIVITY COULD BE LIMITED IN THE MID HUDSON VALLEY AND NW CT SINCE THE UPPER ENERGY IS PREDICTED TO TRACK THROUGH MAINLY NORTHERN AND CENTRAL AREAS. HIGHS SUNDAY IN THE 80S TO LOWER 90S...WITH THE WARMEST TEMPERATURES IN THE MID HUDSON VALLEY AND NW CT. THE MAIN CENTER OF THE UPPER ENERGY TRACKS JUST SOUTH OF THE REGION MONDAY AND MONDAY AFTERNOON...BUT LOW LEVEL FORCING WITH A LITTLE BIT OF COOLING AT THE BOUNDARY LAYER AND THE UPPER DYNAMICS SHOULD SUPPORT INCREASED COVERAGE OF CLOUDS...SHOWERS AND THUNDERSTORMS. HIGHS MONDAY SHOULD BE IN THE MID 80S...NEAR 80 IN THE SOUTHERN ADIRONDACKS AND UPPER 80S MID HUDSON VALLEY AND NW CT. LOCALLY HEAVY RAIN BOTH SUNDAY AND MONDAY COULD RESULT IN LOCALIZED FLASH FLOODING AND A WATCH COULD BE CONSIDERED OVERNIGHT OR TOMORROW DEPENDING ON HOW MUCH COVERAGE OF SHOWERS AND THUNDERSTORMS COULD BE EXPECTED...SO STAY TUNED. THERE ARE INDICATIONS THAT THE UPPER ENERGY AND WEAK COLD FRONT EXIT THE REGION MONDAY NIGHT...WITH SOME POTENTIAL PARTIAL CLEARING OUTSIDE OF AREAS OF FOG BY EARLY TUESDAY MORNING. LOWS SHOULD BE IN THE 60S...WITH MAYBE SOME MID TO UPPER 50S IN THE SOUTHERN ADIRONDACKS. ON TUESDAY...SOME WEAK UPPER RIDGING SHOULD BE OVER THE REGION...BUT THE ATMOSPHERE SHOULD STILL BE UNSTABLE... EVEN WITH NO REAL ORGANIZED LOW LEVEL FOCUS. SO...THERE COULD BE ISOLATED SHOWERS AND THUNDERSTORMS IN THE SOUTHERN HALF OF THE FORECAST AREA WITH HIGHS IN THE 80S. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... THE PERIOD STARTS OUT LATE TUESDAY NIGHT INTO WEDNESDAY WITH A WARM FRONT AND/OR PRE-FRONTAL TROUGH APPROACHING THE AREA FROM THE GREAT LAKES AND OHIO VALLEY. THIS SYSTEM WILL BRING ADDITIONAL CHANCES FOR AT LEAST SCATTERED SHOWERS AND THUNDERSTORMS. THE EVENTUAL INTENSITY OF T-STORMS WILL DEPEND ON THE DEGREE OF INSTABILITY...WHICH WILL BE TIED TO CLOUD COVER. THERE SHOULD BE DECENT FLOW ALOFT FOR MID JULY WITH A MIGRATORY SUB-1000MB CYCLONE TRACKING EASTWARD NEAR HUDSON BAY. THE FIRST SERIES OF FRONTAL BOUNDARY WILL PASS THROUGH BY SOMETIME LATE WEDNESDAY OR WEDNESDAY NIGHT...WHILE THE MAIN COLD FRONT IS FORECAST TO SAG SOUTHWARD ACROSS THE AREA LATE WEDNESDAY NIGHT INTO THURSDAY. WILL CONTINUE TO MENTION CHANCE POPS DURING THIS TIME...WITH THE POSSIBLY MORE ROBUST CONVECTION OCCURRING ON WEDNESDAY. THERE COULD BE AN ADDITIONAL ROUND OF T-STORMS SOUTH OF ALBANY ON THURSDAY IF THE FRONT SLOWS ENOUGH...WHICH IS BEING DEPICTED BY THE 12Z GFS AND ECMWF. IT AT LEAST LOOKS LIKE TEMPERATURES AND HUMIDITY LEVELS WILL START TO SOMEWHAT DROP BY WEEK`S END AS A COOLER NORTHERLY FLOW DEVELOPS IN WAKE OF THE COLD FRONT. HOWEVER...THE CHAOTIC UPPER LEVEL PATTERN MAY ALLOW FOR A CUT-OFF LOW TO FORM SOMEWHAT IN THE VICINITY OF THE OHIO VALLEY...MID ATLANTIC...OR SOUTHERN APPALACHIANS REGION WHICH COULD RESULT IN A MOIST SOUTHERLY FLOW QUICKLY RETURNING BY THE WEEKEND ALONG WITH RENEWED CHANCES FOR PRECIP AND INCREASING HUMIDITY. THERE STILL CONSIDERABLE UNCERTAINTY IN HOW THE PATTERN WILL EVENTUALLY UNFOLD...BUT BOTH THE GFS AND ECMWF ARE DEPICTING A CUT-OFF LOW FORMING SOUTH AND WEST OF OUR AREA NEXT WEEKEND. && .AVIATION /06Z SUNDAY THROUGH THURSDAY/... ANTICIPATING MAINLY VFR CONDITIONS THROUGH THE FORECAST PERIOD. SOME SHRA /NO TSRA OBSERVED YET/ ACTIVITY TRACKING ALONG NY/PA BORDER NEAR AND SOUTH OF BGM. DONT EXPECT THIS TO SURVIVE TO KPOU. NOT CLEAR IF THE USUAL TROUBLE SPOTS OF KPSF AND KGFL WILL SLIDE INTO IFR CONDITIONS OVERNIGHT. DRIER AIR IN EVIDENCE AT THOSE TERMINALS TODAY WITH DEW POINTS INTO MID 60S. FOR NOW...WILL CONTINUE WITH IDEA OF MVFR BR THERE. AT KPOU AND KALB...VFR CONDITIONS. TOMORROW...HAVE INCLUDED /VCSH/ FOR THE AFTERNOON AT ALL TERMINAL EX KPOU. BETTER ORGANIZED SYSTEM WILL BE MOVING ACROSS NORTHERN PORTION OF THE REGION. TIMING...INTENSITY... DURATION...NOT CLEAR AT THIS POINT. SO VCSH WILL SUFFICE. HAVE NOT INCLUDED VCSH AT KPOU. AS NOTED...BETTER CHANCES TO THE NORTH. ALSO COULD SEE SOME TSRA AT TERMINALS...BUT AGAIN LIKELIHOOD/TIMING NOT APPARENT ENOUGH TO INCLUDE IN THE TAFS THIS FAR OUT. OUTLOOK... SUN NITE-TUE...MAINLY VFR. SCT MAINLY AFTERNOON AND EVENING SHRA/TSRA. POSSIBLE LATE NIGHT AND/OR EARLY MORNING FOG/LOW STRATUS WITH MVFR/IFR POSSIBLE. && .FIRE WEATHER... NO FIRE WEATHER ISSUES ARE EXPECTED OVER THE NEXT SEVERAL DAYS. FUELS CONTINUE TO REMAIN SATURATED FROM RECENT SHOWER/THUNDERSTORM ACTIVITY. THERE WILL CONTINUE TO BE A CHANCE FOR AFTERNOON/EVENING SHOWERS AND THUNDERSTORMS FOR THE NEXT SEVERAL DAYS AS THE BERMUDA HIGH KEEPS A HOT AND HUMID AIR MASS ENTRENCHED OVER THE REGION. NORMAL RH RECOVERIES EACH NIGHT BETWEEN 80 TO 100 PERCENT WILL ALLOW FOR WIDESPREAD DEW FORMATION. DAYTIME RH VALUES WILL GENERALLY BE IN THE 40 TO 60 PERCENT RANGE. && .HYDROLOGY... THE MOHAWK RIVER AT UTICA CONTINUES TO EXPERIENCE MINOR FLOODING. THE RIVER AND CREEK FLOWS NEAR THE WEST CENTRAL MOHAWK RIVER ARE EXPECTED TO GRADUALLY RECEDE INTO THE WEEKEND...UNLESS ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS OCCUR OVER OR NEAR THE BASIN. THERE COULD BE SCATTERED SHOWERS AND THUNDERSTORMS SUNDAY AFTERNOON AND EVEN MORE COVERAGE OF SHOWERS AND THUNDERSTORMS MONDAY AFTERNOON AND EVENING WITH THE APPROACH OF A WEAK COLD FRONT. A MOIST AND HUMID AIR MASS WILL ALLOW ANY SHOWER OR THUNDERSTORM TO BE CAPABLE OF PRODUCING LOCALLY HEAVY DOWNPOURS...AND A QUICK INCH OR MORE OF RAINFALL DUE TO THE ANOMALOUS PRECIPITABLE WATER VALUES. THERE WILL BE A CONTINUED THREAT FOR ISOLATED FLASH FLOODING...AS WELL AS FLOODING OF POOR DRAINAGE AND LOW LYING AREAS. NO FLASH FLOOD WATCHES ARE BEING ISSUED DUE TO THE EXPECTED ISOLATED NATURE OF ANY FLOODING. IT IS ALSO DIFFICULT TO DETERMINE WHERE THE HEAVIEST RAINFALL WILL OCCUR. WHILE ADDITIONAL FLOODING IS NOT ANTICIPATED ON ANY MAIN STEM RIVER POINTS...LOCALLY SHARP RISES ARE POSSIBLE DUE TO ANY CONVECTION THAT MAY OCCUR OVER THE NEXT SEVERAL DAYS...ESPECIALLY FOR THOSE POINTS THAT ARE MORE FLASHIER IN NATURE. FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. MA...NONE. VT...NONE. && $$ SYNOPSIS...HWJIV NEAR TERM...HWJIV/OKEEFE SHORT TERM...NAS LONG TERM...JPV AVIATION...OKEEFE FIRE WEATHER...NAS HYDROLOGY...NAS
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
641 AM EDT Sun Jul 7 2013 ...UPDATED FOR HYDROLOGY SECTION... .NEAR TERM [Today]... Showers and isold tstms assocd with meeting of Gulf and east coast seabreezes across Ern most counties late Sat eve weakened after midnight. HRRR overforecast predawn precipitation over Wrn waters and adjacent coastlines. Updated overnight grids to reflect this. The large scale longwave blocking pattern continues to deamplify. This is highlighted by a ridge over Wrn half of Conus, and a lifting trough over Cntrl and Ern states with base over TN Valley and upper low spinning from Mid Ms Valley into OH Valley. Looking east, a ridge extends from high in Wrn Atlc a few hundred miles east of Carolina coast WSW down South Atlc seaboard. Looking southeast, TUTT low spinning invcnty of Bahamas. At the surface, Sly flow around Wrn Atlc Bermuda high will remain over SE region. During the rest of today, expect further lifting of low which will reach Srn Great Lakes around sundown. This will allow Atlc high to nose Swwd and deep layer ridge to encroach further inland pushing tropical plume responsible for recent heavy rains further west of our area. It will also combine with Wwd movement of TUTT placing CWA closer to its subsident side. By this eve, TUTT actually moves under ridge shifitng it back a little ewd. Lifting trough will also help flatten Wrn and Atlc ridges and allow them to begin to bridge under trough. However surface ridge axis remains to our north so ample low level moisture remains. All this translates to increasing and strong upper subsidence and dry air overspreading from the Atlc Swwd and Nwwd to across local area. This reflected in model soundings which show sharp W-E increase in mid level dry air and in decreasing PWAT. i.e. GFS at 00z Mon with 1.79 in and 1.35 inches at TLH and JAX respectively. Thus scenario shifting somewhat to a more typical summertime pattern of diurnal sea breeze convection especially east of the Apalachicola River and with a continued sharp E-W POP/cloud gradient as reflected in CAM and other High Res models. Will go with 20-60% SE-NW POP gradient. Increasing dry air aloft should decrease aerial coverage and delay onset of any storms compared to previous days. Although the concentrated bands of heavy, flooding rains are not expected and the flood watch has expired, soils over the Florida Panhandle and into Southeast Alabama remain quite moist, so any rainfall could cause some localized flooding issues if rainfall rates are high enough. CAM flood tool still shows up to 30% possibility. With more sunshine expected than recent days, temps should rebound back to near seasonal levels with highs in the mid-upper 80s west to low 90s east. && .SHORT TERM [Tonight Through Tuesday]... The blocky pattern of the past week will completely break down during this period as the Midwest upper low opens up and ejects east across New England by Monday night. The Atlantic ridge will be further weakened as it is undercut by the TUTT low, which will reach far South FL on Tuesday. These transformations will finally cut off the flow of deep layer tropical air into the region and allow the dry air seen on water vapor imagery over the Atlantic to work its way westward into the forecast area. At the surface, the subtropical ridge axis will extend across the Southeast U.S. through the period. The ridge axis will be north of the area through Monday and then slip to near the Gulf Coast on Tuesday. However, because of the influence of drier air aloft, rain chances will actually dip to below normal levels for this time of year, a refreshing change from the recent rains. Of course, the flip side of getting less rain is that temps will rise closer to seasonal levels. Highs Monday will be near normal in the lower 90s. On Tuesday, we will actually see slightly above normal max temps in the mid 90s across many inland locations. && .LONG TERM [Tuesday Night through Saturday]... A fairly typical summertime pattern is expected with daily diurnal convection through the period. By mid-week, an upper level low is expected to approach from the southeast which could enhance rain chances a little bit. Towards the end of the week as ridging builds over the Plains, we may temporarily transition to more of a northwest flow pattern with a weak front approaching from the northwest. Near seasonal temperatures are expected. && .AVIATION [Through 12z Monday]... Lower ceilings/vsbys remain possible with all sites except ECP possibly experiencing IFR conditions thru 13Z. By mid morning hours, more showers and thunderstorms could develop around north Florida with precipitation chances spreading to all other terminals by the afternoon. DHN and ECP will have the highest chances of receiving precipitation. Brief MVFR CIGS/VSBYS possible in any heavy rain. VFR conditions are expected 00z-08z then MVFR CIGS/VSBYS again possible 08Z-12Z where residual moisture remains from today`s rains. && .MARINE... A surface ridge of high pressure will become reestablished north of the area this week allowing winds and seas to return to typical summertime levels. Winds will generally be out of the east or southeast. && .FIRE WEATHER... Red Flag conditions are not expected in the foreseeable future. && .HYDROLOGY... The overall threat for significant flooding has largely ended. Most rivers across our area are either nearing their crest or have recently crested. The greatest impacts continue to be on the Choctawhatchee River at Bruce-Ebro which will reach major flood stage. The Sopchoppy River moved above moderate flood overnight but should gradually fall through today. The following rivers are at minor stage. The Withlacoochee above Valdosta, St Marks near Newport, Apalachicola near Blountstown, Choctawatchee at Caryville and about to go into moderate flooding for today is the Choctawhatchee at Geneva. && .PRELIMINARY POINT TEMPS/POPS... Tallahassee 90 73 91 72 94 / 50 20 40 20 30 Panama City 86 75 89 74 91 / 60 20 40 20 20 Dothan 88 73 91 72 95 / 60 30 40 20 30 Albany 91 74 92 73 94 / 60 30 40 20 30 Valdosta 91 72 92 70 93 / 30 20 40 20 30 Cross City 92 70 93 69 94 / 20 20 30 20 30 Apalachicola 86 74 88 74 89 / 50 20 30 20 20 && .TAE WATCHES/WARNINGS/ADVISORIES... FL...None. GA...None. AL...None. GM...None. && $$ Near Term/Aviation/Fire Weather...Block Long Term...DVD Hydrology...Block/Wool Rest of Discussion...Wool
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
439 AM EDT Sun Jul 7 2013 ...UPDATED FOR LACK OF PREDAWN RAIN AND FOR AVIATION SECTION... .NEAR TERM [Today]... Showers and isold tstms assocd with meeting of Gulf and east coast seabreezes across Ern most counties late Sat eve weakened after midnight. HRRR overforecast predawn precipitation over Wrn waters and adjacent coastlines. Updated overnight grids to reflect this. The large scale longwave blocking pattern continues to deamplify. This is highlighted by a ridge over Wrn half of Conus, and a lifting trough over Cntrl and Ern states with base over TN Valley and upper low spinning from Mid Ms Valley into OH Valley. Looking east, a ridge extends from high in Wrn Atlc a few hundred miles east of Carolina coast WSW down South Atlc seaboard. Looking southeast, TUTT low spinning invcnty of Bahamas. At the surface, Sly flow around Wrn Atlc Bermuda high will remain over SE region. During the rest of today, expect further lifting of low which will reach Srn Great Lakes around sundown. This will allow Atlc high to nose Swwd and deep layer ridge to encroach further inland pushing tropical plume responsible for recent heavy rains further west of our area. It will also combine with Wwd movement of TUTT placing CWA closer to its subsident side. By this eve, TUTT actually moves under ridge shifitng it back a little ewd. Lifting trough will also help flatten Wrn and Atlc ridges and allow them to begin to bridge under trough. However surface ridge axis remains to our north so ample low level moisture remains. All this translates to increasing and strong upper subsidence and dry air overspreading from the Atlc Swwd and Nwwd to across local area. This reflected in model soundings which show sharp W-E increase in mid level dry air and in decreasing PWAT. i.e. GFS at 00z Mon with 1.79 in and 1.35 inches at TLH and JAX respectively. Thus scenario shifting somewhat to a more typical summertime pattern of diurnal sea breeze convection especially east of the Apalachicola River and with a continued sharp E-W POP/cloud gradient as reflected in CAM and other High Res models. Will go with 20-60% SE-NW POP gradient. Increasing dry air aloft should decrease aerial coverage and delay onset of any storms compared to previous days. Although the concentrated bands of heavy, flooding rains are not expected and the flood watch has expired, soils over the Florida Panhandle and into Southeast Alabama remain quite moist, so any rainfall could cause some localized flooding issues if rainfall rates are high enough. CAM flood tool still shows up to 30% possibility. With more sunshine expected than recent days, temps should rebound back to near seasonal levels with highs in the mid-upper 80s west to low 90s east. && .SHORT TERM [Tonight Through Tuesday]... The blocky pattern of the past week will completely break down during this period as the Midwest upper low opens up and ejects east across New England by Monday night. The Atlantic ridge will be further weakened as it is undercut by the TUTT low, which will reach far South FL on Tuesday. These transformations will finally cut off the flow of deep layer tropical air into the region and allow the dry air seen on water vapor imagery over the Atlantic to work its way westward into the forecast area. At the surface, the subtropical ridge axis will extend across the Southeast U.S. through the period. The ridge axis will be north of the area through Monday and then slip to near the Gulf Coast on Tuesday. However, because of the influence of drier air aloft, rain chances will actually dip to below normal levels for this time of year, a refreshing change from the recent rains. Of course, the flip side of getting less rain is that temps will rise closer to seasonal levels. Highs Monday will be near normal in the lower 90s. On Tuesday, we will actually see slightly above normal max temps in the mid 90s across many inland locations. && .LONG TERM [Tuesday Night through Saturday]... A fairly typical summertime pattern is expected with daily diurnal convection through the period. By mid-week, an upper level low is expected to approach from the southeast which could enhance rain chances a little bit. Towards the end of the week as ridging builds over the Plains, we may temporarily transition to more of a northwest flow pattern with a weak front approaching from the northwest. Near seasonal temperatures are expected. && .AVIATION [Through 12z Monday]... Lower ceilings/vsbys remain possible with all sites except ECP possibly experiencing IFR conditions thru 13Z. By mid morning hours, more showers and thunderstorms could develop around north Florida with precipitation chances spreading to all other terminals by the afternoon. DHN and ECP will have the highest chances of receiving precipitation. Brief MVFR CIGS/VSBYS possible in any heavy rain. VFR conditions are expected 00z-08z then MVFR CIGS/VSBYS again possible 08Z-12Z where residual moisture remains from today`s rains. && .MARINE... A surface ridge of high pressure will become reestablished north of the area this week allowing winds and seas to return to typical summertime levels. Winds will generally be out of the east or southeast. && .FIRE WEATHER... Red Flag conditions are not expected in the foreseeable future. && .HYDROLOGY... The overall threat for significant flooding has largely ended. Most rivers across our area are either nearing their crest or have recently crested. The greatest impacts continue to be on the Choctawhatchee River at Bruce-Ebro which will reach major flood stage. The Sopchoppy River moved above moderate flood overnight but should gradually fall through today. All other rivers where flooding is expected should generally crest in minor flood stage. && .PRELIMINARY POINT TEMPS/POPS... Tallahassee 90 73 91 72 94 / 50 20 40 20 30 Panama City 86 75 89 74 91 / 60 20 40 20 20 Dothan 88 73 91 72 95 / 60 30 40 20 30 Albany 91 74 92 73 94 / 60 30 40 20 30 Valdosta 91 72 92 70 93 / 30 20 40 20 30 Cross City 92 70 93 69 94 / 20 20 30 20 30 Apalachicola 86 74 88 74 89 / 50 20 30 20 20 && .TAE WATCHES/WARNINGS/ADVISORIES... FL...None. GA...None. AL...None. GM...None. && $$ Near Term/Aviation/Fire Weather...Block Long Term...DVD Hydrology...Block/Wool Rest of Discussion...Wool
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
250 AM EDT Sun Jul 7 2013 .NEAR TERM [Through Today]... Showers and isold tstms assocd with meeting of Gulf and east coast sea breezes across Ern most counties late Sat eve weakened after midnight. HRRR shows rain south of Panama City Beach, but for the most part, expect the bulk of this rain to remain just offshore into this morning. The large scale long wave blocking pattern continues to deamplify. This is highlighted by a ridge over Wrn half of CONUS, and a lifting trough over Cntrl and Ern states with base over TN Valley and upper low spinning over Mid MS Valley. Looking east, a ridge extends Ewd into Wrn Atlc with high east of NC coast with axis down Ern seaboard. Looking southeast, TUTT low spinning in vcnty of the Bahamas. At the surface, Sly flow around Wrn Atlc high will remain over SE region. During the rest of today, expect further lifting of low which will reach Srn Great Lakes around sundown. This will allow Atlc high to nose Swwd and deep layer ridge to encroach further inland and combine with Wwd movement of TUTT placing CWA closer to its subsident side. Lifting trough will also help flatten Wrn and Atlc ridges and allow them to begin to bridge under trough. All this translates to increasing and strong upper subsidence and dry air overspreading from from the Atlc Swwd and Nwwd to across local area. This reflected in model soundings which show sharp W-E increase in mid level dry air and in decreasing PWAT. i.e. GFS at 00z Mon with 1.79 in and 1.35 inches at TLH and JAX respectively. However surface ridge axis remains to our north so ample low level moisture remains. Thus scenario shifting somewhat to a more typical summertime pattern of diurnal sea breeze convection especially east of the Apalachicola River and with a continued sharp E-W POP/cloud gradient as reflected in CAM and other High Res models. Will go with 20-60% SE-NW POP gradient. Increasing dry air aloft should decrease aerial coverage and delay onset of any storms compared to previous days. Although the concentrated bands of heavy, flooding rains are not expected and the flood watch has expired, soils over the Florida Panhandle and into Southeast Alabama remain quite moist, so any rainfall over the next few days could cause some localized flooding issues if rainfall rates are high enough. CAM flood tool still shows up to 30% possibility. With more sunshine expected than recent days, temps should rebound back to near seasonal levels with highs in the mid-upper 80s west to low 90s east. && .SHORT TERM [Tonight Through Tuesday]... The blocky pattern of the past week will completely break down during this period as the Midwest upper low opens up and ejects east across New England by Monday night. The Atlantic ridge will be further weakened as it is undercut by the TUTT low, which will reach far South FL on Tuesday. These transformations will finally cut off the flow of deep layer tropical air into the region and allow the dry air seen on water vapor imagery over the Atlantic to work its way westward into the forecast area. At the surface, the subtropical ridge axis will extend across the Southeast U.S. through the period. The ridge axis will be north of the area through Monday and then slip to near the Gulf Coast on Tuesday. However, because of the influence of drier air aloft, rain chances will actually dip to below normal levels for this time of year, a refreshing change from the recent rains. Of course, the flip side of getting less rain is that temps will rise closer to seasonal levels. Highs Monday will be near normal in the lower 90s. On Tuesday, we will actually see slightly above normal max temps in the mid 90s across many inland locations. && .LONG TERM [Tuesday Night through Saturday]... A fairly typical summertime pattern is expected with daily diurnal convection through the period. By mid-week, an upper level low is expected to approach from the southeast which could enhance rain chances a little bit. Towards the end of the week as ridging builds over the Plains, we may temporarily transition to more of a northwest flow pattern with a weak front approaching from the northwest. Near seasonal temperatures are expected. && .AVIATION... [Through 06z Monday] Lower ceilings are a possibility in the early morning hours on Sunday, with all sites except ECP possibly experiencing IFR conditions thru 13Z. By the late morning hours, more showers and thunderstorms could develop around north Florida, impacting ECP and TLH, with precipitation chances spreading to all other terminals by the afternoon. DHN and ECP will have the highest chances of receiving precipitation tomorrow, with IFR conditions possible in any thunderstorms that develop. VFR conditions are expected 00z-06z. && .MARINE... A surface ridge of high pressure will become reestablished north of the area this week allowing winds and seas to return to typical summertime levels. Winds will generally be out of the east or southeast. && .FIRE WEATHER... Red Flag conditions are not expected in the foreseeable future. && .HYDROLOGY... Only light showers were noted overnight. The overall threat for significant flooding has largely ended. Most rivers across our area are either nearing their crest or have recently crested. The greatest impacts continue to be on the Choctawhatchee River at Bruce-Ebro which has reached major flood stage and will remain above that level for several days. The latest crest forecast is nearly a foot and a half above the previous forecast and should occur on Monday. The Sopchoppy River moved above moderate flood overnight but appears to have crested and should gradually fall through today. All other rivers where flooding is expected should generally crest in minor flood stage. && .PRELIMINARY POINT TEMPS/POPS... Tallahassee 90 73 91 72 94 / 50 20 40 20 30 Panama City 86 75 89 74 91 / 60 20 40 20 20 Dothan 88 73 91 72 95 / 60 30 40 20 30 Albany 91 74 92 73 94 / 60 30 40 20 30 Valdosta 91 72 92 70 93 / 30 20 40 20 30 Cross City 92 70 93 69 94 / 20 20 30 20 30 Apalachicola 86 74 88 74 89 / 50 20 30 20 20 && .TAE WATCHES/WARNINGS/ADVISORIES... FL...None. GA...None. AL...None. GM...None. && $$ Near Term/Aviation/Fire Weather...Block Long Term...DVD Hydrology...Block/Wool Rest of Discussion...Wool
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
219 PM EDT SUN JUL 7 2013 .PREV DISCUSSION... /ISSUED 730 AM EDT SUN JUL 7 2013/ PREV DISCUSSION... /ISSUED 355 AM EDT SUN JUL 7 2013/ SHORT TERM /TODAY THROUGH MONDAY/... WATER VAPOR LOOP CONTINUES TO SHOW DEEP MOISTURE BEING FUNNELED INTO W GA FROM THE TROPICS. PWATS HAVE BUMPED BACK UP TO AROUND 2 INCHES ACROSS NORTHERN GA ACCORDING TO THE 00Z FFC SOUNDING. MODELS SHOW THIS HIGH MOISTURE AXIS REMAINING ACROSS THE CWFA THROUGH TONIGHT. SOMEWHAT DRIER AIR HAS MOVED IN ACROSS THE EASTERN PORTION OF THE CWFA. UPPER LOW ACROSS THE OHIO VALLEY WILL SLOWLY EJECT INTO THE MIDDLE ATLANTIC BY EARLY MONDAY MORNING. MEANWHILE...THE BERMUDA HIGH AT THE SURFACE WILL BEGIN TO BUILD WESTWARD...ALSO HELPING SHIFT THE TROPICAL PLUME WESTWARD. THIS SHOULD RESULT IN A DECREASE IN PWATS/MOISTURE CONTENT DURING THE DAY ON MONDAY. LATEST RUNS OF THE HRRR SHOW THE BEST CHANCE FOR POPS IS IN NW GA THIS MORNING. THIS SEEMS REASONABLE AS PRECIP AXIS HAS NOT MOVED MOST OF THE NIGHT. SCT/NMRS SHOWERS AND THUNDERSTORMS ARE EXPECTED ACROSS THE REMAINDER OF THE CWFA THIS AFT/EVE BUT THEY SHOULD BE MORE DIURNALLY DRIVEN. FFG IS LESS THAN AN INCH AND A HALF ACROSS AREAS MOSTLY NORTH OF THE FALL LINE. WILL NOT MAKE ANY CHANGES TO THE FLOOD WATCH FOR NOW. NLISTEMAA LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... EXTENDED BEGINS WITH UPPER WAVE MOVING OFF THE NEW ENGLAND COAST WHILE CLOSED LOW OVER THE BAHAMAS IS WORKING ITS WAY WEST...AND BETWEEN THESE TWO THE ATLANTIC HIGH IS RIDGING INTO THE SOUTHEAST. THE EXITING SYSTEM ACROSS NEW ENGLAND ALLOWS THE ASSOCIATED SURFACE BOUNDARY/FRONT TO ELONGATE AND STRETCH ACROSS THE SOUTHEAST. BEST PRECIP CHANCES WILL BE ACROSS NORTH GEORGIA. ANOTHER LONGWAVE TROUGH PUSHES INTO SOUTHERN CANADA AND THE UPPER MISSISSIPPI VALLEY BY MIDWEEK AND WITH CONTINUE SOUTHERLY FLOW FROM THE ATLANTIC AND GULF...PRECIP CHANCES INCREASE AGAIN WEDNESDAY AND ESPECIALLY INTO THURSDAY AS THE TROUGH DIGS INTO THE OHIO VALLEY AND A SURFACE FRONT MOVES INTO THE TENNESSEE VALLEY. REALLY REMARKABLE AGREEMENT BETWEEN THE GFS AND ECMWF THROUGH THIS PERIOD...THOUGH THE ECMWF IS A TAD DEEPER WITH THE WAVE INTO THE SOUTHEAST AND A LITTLE BIT MORE NEGATIVELY TILTED. LATE IN THE WORK WEEK THIS TROUGH CONTINUES TO DIG AND DEEPEN INTO THE GREAT LAKES...EVENTUALLY FORMING A CUTOFF LOW OVER THE UPPER OHIO VALLEY. GFS A LITTLE FASTER WITH THIS TRANSITION BUT STILL PRETTY SIMILAR IN OVERALL DEPICTION. TROUGH AXIS PROGGED TO BE GENERALLY ACROSS THE MIDDLE OF THE STATE...THUS REDUCING PRECIP CHANCES ACROSS NORTHWEST GEORGIA BUT KEEPING POPS IN SOUTHEAST ZONES. THE LOW CONTINUES TO DEEPEN AND DIG TO THE SOUTHWEST... RETROGRADING IN RESPONSE TO DEEPENING UPPER HIGH OVER THE DESERT SOUTHWEST AND WESTERN PLAINS. BY THE END OF THE PERIOD THE CUTOFF LOW IS SOMEWHERE EITHER IN THE TENNESSEE VALLEY OR SOUTHEAST... WITH BOTH MODELS CONTINUING TO RETROGRADE IT TO THE WEST BEYOND THE END OF THE PERIOD. SO IN GENERAL...IT LOOKS LIKE NEXT WEEK COULD BE A REPEAT OF WHAT WE SAW THIS PAST WEEK WITH SIGNIFICANT MOISTURE TRANSPORT OUT OF THE GULF. WILL WAIT AND SEE HOW THIS PLAYS OUT. TEMPS REMAIN AT OR BELOW NORMAL THROUGH THE PERIOD. IF WE HAVE TO PUT UP WITH ALL THE RAIN AND POTENTIAL FLOODING...AT LEAST WE GET COOLER TEMPS OUT OF IT. HOWEVER...THERE IS A LARGER CONCERN THAT WITH THIS CONTINUED WET PATTERN WE COULD BE SETTING THE STAGE FOR SOME REAL PROBLEMS IF WE GET A TROPICAL SYSTEM MOVING IN. TDP && .AVIATION... 18Z UPDATE... MOSTLY LIGHT RAIN ACROSS THE AREA RIGHT NOW WITH VFR TO MVFR CEILINGS AND VSBYS. THIS LIGHT RAIN IS EXPECTED TO CONTINUE THROUGH THE FORECAST PERIOD. THE RAIN WILL DIMINISH SOME OVER NIGHT BUT RETURN AGAIN MONDAY. WINDS ARE OUT OF THE SW AND SHOULD TURN TO THE SE AFTER 00Z. WINDS WILL GO BACK TO THE SW MONDAY AFTER 16-18Z. WINDS SPEEDS WILL STAY IN THE 5-10KT RANGE. CEILINGS AND VSBYS SHOULD STAY IN THE VFR TO MVFR RANGE. //ATL CONFIDENCE...18Z UPDATE... CONFIDENCE MEDIUM ON ALL ELEMENTS. 01 && .PRELIMINARY POINT TEMPS/POPS... ATHENS 82 70 86 71 / 70 50 50 30 ATLANTA 81 70 84 72 / 70 40 50 30 BLAIRSVILLE 75 67 78 66 / 70 50 60 30 CARTERSVILLE 80 69 86 69 / 70 40 60 30 COLUMBUS 84 73 89 73 / 70 30 50 20 GAINESVILLE 79 68 83 71 / 70 50 60 30 MACON 86 73 88 72 / 70 30 50 20 ROME 80 70 86 70 / 70 50 60 30 PEACHTREE CITY 81 70 84 70 / 70 40 50 30 VIDALIA 89 72 90 72 / 50 30 30 20 && .FFC WATCHES/WARNINGS/ADVISORIES... FLOOD WATCH UNTIL 8 PM EDT THIS EVENING FOR THE FOLLOWING ZONES: BANKS...BARROW...BARTOW...CARROLL...CATOOSA...CHATTOOGA... CHEROKEE...CLARKE...CLAYTON...COBB...COWETA...DADE...DAWSON... DEKALB...DOUGLAS...FANNIN...FAYETTE...FLOYD...FORSYTH...GILMER... GORDON...GREENE...GWINNETT...HALL...HARALSON...HEARD...HENRY... JACKSON...LUMPKIN...MADISON...MORGAN...MURRAY...NEWTON...NORTH FULTON...OCONEE...OGLETHORPE...PAULDING...PICKENS...POLK... ROCKDALE...SOUTH FULTON...TALIAFERRO...TOWNS...UNION...WALKER... WALTON...WHITE...WHITFIELD...WILKES. && $$ SHORT TERM...01 LONG TERM....41 AVIATION...01
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
730 AM EDT SUN JUL 7 2013 .PREV DISCUSSION... /ISSUED 355 AM EDT SUN JUL 7 2013/ SHORT TERM /TODAY THROUGH MONDAY/... WATER VAPOR LOOP CONTINUES TO SHOW DEEP MOISTURE BEING FUNNELED INTO W GA FROM THE TROPICS. PWATS HAVE BUMPED BACK UP TO AROUND 2 INCHES ACROSS NORTHERN GA ACCORDING TO THE 00Z FFC SOUNDING. MODELS SHOW THIS HIGH MOISTURE AXIS REMAINING ACROSS THE CWFA THROUGH TONIGHT. SOMEWHAT DRIER AIR HAS MOVED IN ACROSS THE EASTERN PORTION OF THE CWFA. UPPER LOW ACROSS THE OHIO VALLEY WILL SLOWLY EJECT INTO THE MIDDLE ATLANTIC BY EARLY MONDAY MORNING. MEANWHILE...THE BERMUDA HIGH AT THE SURFACE WILL BEGIN TO BUILD WESTWARD...ALSO HELPING SHIFT THE TROPICAL PLUME WESTWARD. THIS SHOULD RESULT IN A DECREASE IN PWATS/MOISTURE CONTENT DURING THE DAY ON MONDAY. LATEST RUNS OF THE HRRR SHOW THE BEST CHANCE FOR POPS IS IN NW GA THIS MORNING. THIS SEEMS REASONABLE AS PRECIP AXIS HAS NOT MOVED MOST OF THE NIGHT. SCT/NMRS SHOWERS AND THUNDERSTORMS ARE EXPECTED ACROSS THE REMAINDER OF THE CWFA THIS AFT/EVE BUT THEY SHOULD BE MORE DIURNALLY DRIVEN. FFG IS LESS THAN AN INCH AND A HALF ACROSS AREAS MOSTLY NORTH OF THE FALL LINE. WILL NOT MAKE ANY CHANGES TO THE FLOOD WATCH FOR NOW. NLISTEMAA LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... EXTENDED BEGINS WITH UPPER WAVE MOVING OFF THE NEW ENGLAND COAST WHILE CLOSED LOW OVER THE BAHAMAS IS WORKING ITS WAY WEST...AND BETWEEN THESE TWO THE ATLANTIC HIGH IS RIDGING INTO THE SOUTHEAST. THE EXITING SYSTEM ACROSS NEW ENGLAND ALLOWS THE ASSOCIATED SURFACE BOUNDARY/FRONT TO ELONGATE AND STRETCH ACROSS THE SOUTHEAST. BEST PRECIP CHANCES WILL BE ACROSS NORTH GEORGIA. ANOTHER LONGWAVE TROUGH PUSHES INTO SOUTHERN CANADA AND THE UPPER MISSISSIPPI VALLEY BY MIDWEEK AND WITH CONTINUE SOUTHERLY FLOW FROM THE ATLANTIC AND GULF...PRECIP CHANCES INCREASE AGAIN WEDNESDAY AND ESPECIALLY INTO THURSDAY AS THE TROUGH DIGS INTO THE OHIO VALLEY AND A SURFACE FRONT MOVES INTO THE TENNESSEE VALLEY. REALLY REMARKABLE AGREEMENT BETWEEN THE GFS AND ECMWF THROUGH THIS PERIOD...THOUGH THE ECMWF IS A TAD DEEPER WITH THE WAVE INTO THE SOUTHEAST AND A LITTLE BIT MORE NEGATIVELY TILTED. LATE IN THE WORK WEEK THIS TROUGH CONTINUES TO DIG AND DEEPEN INTO THE GREAT LAKES...EVENTUALLY FORMING A CUTOFF LOW OVER THE UPPER OHIO VALLEY. GFS A LITTLE FASTER WITH THIS TRANSITION BUT STILL PRETTY SIMILAR IN OVERALL DEPICTION. TROUGH AXIS PROGGED TO BE GENERALLY ACROSS THE MIDDLE OF THE STATE...THUS REDUCING PRECIP CHANCES ACROSS NORTHWEST GEORGIA BUT KEEPING POPS IN SOUTHEAST ZONES. THE LOW CONTINUES TO DEEPEN AND DIG TO THE SOUTHWEST... RETROGRADING IN RESPONSE TO DEEPENING UPPER HIGH OVER THE DESERT SOUTHWEST AND WESTERN PLAINS. BY THE END OF THE PERIOD THE CUTOFF LOW IS SOMEWHERE EITHER IN THE TENNESSEE VALLEY OR SOUTHEAST... WITH BOTH MODELS CONTINUING TO RETROGRADE IT TO THE WEST BEYOND THE END OF THE PERIOD. SO IN GENERAL...IT LOOKS LIKE NEXT WEEK COULD BE A REPEAT OF WHAT WE SAW THIS PAST WEEK WITH SIGNIFICANT MOISTURE TRANSPORT OUT OF THE GULF. WILL WAIT AND SEE HOW THIS PLAYS OUT. TEMPS REMAIN AT OR BELOW NORMAL THROUGH THE PERIOD. IF WE HAVE TO PUT UP WITH ALL THE RAIN AND POTENTIAL FLOODING...AT LEAST WE GET COOLER TEMPS OUT OF IT. HOWEVER...THERE IS A LARGER CONCERN THAT WITH THIS CONTINUED WET PATTERN WE COULD BE SETTING THE STAGE FOR SOME REAL PROBLEMS IF WE GET A TROPICAL SYSTEM MOVING IN. TDP AVIATION... 06Z UPDATE... TROPICAL MOISTURE PLUME CONTINUES ACROSS THE REGION. MODELS ARE SUPPORTING IFR CIGS AT MANY OF THE AIRPORTS THROUGH EARLY SUNDAY MORNING. THE 00Z NAM SOUNDINGS SUPPORT THIS. IN ADDITION...PATCHY MVFR FOG WILL ALSO BE POSSIBLE. SKIES SHOULD REMAIN MCLDY THROUGH THE DAY WITH CIGS BKN AROUND 035-040. SHRA/TSRA WILL DEVELOP DURING PEAK HEATING. LOW CIGS ARE POSSIBLE AGAIN TOMORROW NIGHT. //ATL CONFIDENCE...06Z UPDATE... HIGH CONFIDENCE FOR WINDS. MEDIUM CONFIDENCE REMAINING ELEMENTS. && .AVIATION... 12Z UPDATE... IFR CIGS SHOULD LIFT TO MVFR BY 14-15Z AT ATL. SKIES WILL REMAIN BKN THROUGH THE DAY...BUT VALUES SHOULD BE AROUND 035. DIURNALLY DRIVEN CONVECTION EXPECTED THIS AFTERNOON. LATEST RUN OF THE HRRR HAS BULF OF CONVECTION DEVELOPING JUST TO THE SOUTH OF ATL THIS AFTERNOON...BUT WILL KEEP THE TEMPO GROUP IN DURING PEAK HEATING. DO THINK COVERAGE WILL BE NMRS. LOW CIGS AGAIN TONIGHT...MAY HAVE TO TWEAK TAFS LATER TO IFR VALUES. //ATL CONFIDENCE...12Z UPDATE... MEDIUM CONFIDENCE ALL ELEMENTS. && .PRELIMINARY POINT TEMPS/POPS... ATHENS 82 70 86 71 / 70 40 50 30 ATLANTA 81 70 84 72 / 70 40 50 30 BLAIRSVILLE 75 67 78 66 / 70 50 60 30 CARTERSVILLE 80 69 86 69 / 70 40 60 30 COLUMBUS 84 73 89 73 / 70 30 50 20 GAINESVILLE 79 68 83 71 / 70 50 60 30 MACON 86 73 88 72 / 70 30 50 20 ROME 80 70 86 70 / 70 50 60 30 PEACHTREE CITY 81 70 84 70 / 70 40 50 30 VIDALIA 89 72 90 73 / 50 20 30 20 && .FFC WATCHES/WARNINGS/ADVISORIES... FLOOD WATCH THROUGH THIS EVENING FOR THE FOLLOWING ZONES: BANKS...BARROW...BARTOW...CARROLL...CATOOSA...CHATTOOGA... CHEROKEE...CLARKE...CLAYTON...COBB...COWETA...DADE...DAWSON... DEKALB...DOUGLAS...FANNIN...FAYETTE...FLOYD...FORSYTH...GILMER... GORDON...GREENE...GWINNETT...HALL...HARALSON...HEARD...HENRY... JACKSON...LUMPKIN...MADISON...MORGAN...MURRAY...NEWTON...NORTH FULTON...OCONEE...OGLETHORPE...PAULDING...PICKENS...POLK... ROCKDALE...SOUTH FULTON...TALIAFERRO...TOWNS...UNION...WALKER... WALTON...WHITE...WHITFIELD...WILKES. && $$ SHORT TERM...ATWELL LONG TERM....ATWELL AVIATION...ATWELL
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
355 AM EDT SUN JUL 7 2013 .SHORT TERM /TODAY THROUGH MONDAY/... WATER VAPOR LOOP CONTINUES TO SHOW DEEP MOISTURE BEING FUNNELED INTO W GA FROM THE TROPICS. PWATS HAVE BUMPED BACK UP TO AROUND 2 INCHES ACROSS NORTHERN GA ACCORDING TO THE 00Z FFC SOUNDING. MODELS SHOW THIS HIGH MOISTURE AXIS REMAINING ACROSS THE CWFA THROUGH TONIGHT. SOMEWHAT DRIER AIR HAS MOVED IN ACROSS THE EASTERN PORTION OF THE CWFA. UPPER LOW ACROSS THE OHIO VALLEY WILL SLOWLY EJECT INTO THE MIDDLE ATLANTIC BY EARLY MONDAY MORNING. MEANWHILE...THE BERMUDA HIGH AT THE SURFACE WILL BEGIN TO BUILD WESTWARD...ALSO HELPING SHIFT THE TROPICAL PLUME WESTWARD. THIS SHOULD RESULT IN A DECREASE IN PWATS/MOISTURE CONTENT DURING THE DAY ON MONDAY. LATEST RUNS OF THE HRRR SHOW THE BEST CHANCE FOR POPS IS IN NW GA THIS MORNING. THIS SEEMS REASONABLE AS PRECIP AXIS HAS NOT MOVED MOST OF THE NIGHT. SCT/NMRS SHOWERS AND THUNDERSTORMS ARE EXPECTED ACROSS THE REMAINDER OF THE CWFA THIS AFT/EVE BUT THEY SHOULD BE MORE DIURNALLY DRIVEN. FFG IS LESS THAN AN INCH AND A HALF ACROSS AREAS MOSTLY NORTH OF THE FALL LINE. WILL NOT MAKE ANY CHANGES TO THE FLOOD WATCH FOR NOW. NLISTEMAA .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... EXTENDED BEGINS WITH UPPER WAVE MOVING OFF THE NEW ENGLAND COAST WHILE CLOSED LOW OVER THE BAHAMAS IS WORKING ITS WAY WEST...AND BETWEEN THESE TWO THE ATLANTIC HIGH IS RIDGING INTO THE SOUTHEAST. THE EXITING SYSTEM ACROSS NEW ENGLAND ALLOWS THE ASSOCIATED SURFACE BOUNDARY/FRONT TO ELONGATE AND STRETCH ACROSS THE SOUTHEAST. BEST PRECIP CHANCES WILL BE ACROSS NORTH GEORGIA. ANOTHER LONGWAVE TROUGH PUSHES INTO SOUTHERN CANADA AND THE UPPER MISSISSIPPI VALLEY BY MIDWEEK AND WITH CONTINUE SOUTHERLY FLOW FROM THE ATLANTIC AND GULF...PRECIP CHANCES INCREASE AGAIN WEDNESDAY AND ESPECIALLY INTO THURSDAY AS THE TROUGH DIGS INTO THE OHIO VALLEY AND A SURFACE FRONT MOVES INTO THE TENNESSEE VALLEY. REALLY REMARKABLE AGREEMENT BETWEEN THE GFS AND ECMWF THROUGH THIS PERIOD...THOUGH THE ECMWF IS A TAD DEEPER WITH THE WAVE INTO THE SOUTHEAST AND A LITTLE BIT MORE NEGATIVELY TILTED. LATE IN THE WORK WEEK THIS TROUGH CONTINUES TO DIG AND DEEPEN INTO THE GREAT LAKES...EVENTUALLY FORMING A CUTOFF LOW OVER THE UPPER OHIO VALLEY. GFS A LITTLE FASTER WITH THIS TRANSITION BUT STILL PRETTY SIMILAR IN OVERALL DEPICTION. TROUGH AXIS PROGGED TO BE GENERALLY ACROSS THE MIDDLE OF THE STATE...THUS REDUCING PRECIP CHANCES ACROSS NORTHWEST GEORGIA BUT KEEPING POPS IN SOUTHEAST ZONES. THE LOW CONTINUES TO DEEPEN AND DIG TO THE SOUTHWEST... RETROGRADING IN RESPONSE TO DEEPENING UPPER HIGH OVER THE DESERT SOUTHWEST AND WESTERN PLAINS. BY THE END OF THE PERIOD THE CUTOFF LOW IS SOMEWHERE EITHER IN THE TENNESSEE VALLEY OR SOUTHEAST... WITH BOTH MODELS CONTINUING TO RETROGRADE IT TO THE WEST BEYOND THE END OF THE PERIOD. SO IN GENERAL...IT LOOKS LIKE NEXT WEEK COULD BE A REPEAT OF WHAT WE SAW THIS PAST WEEK WITH SIGNIFICANT MOISTURE TRANSPORT OUT OF THE GULF. WILL WAIT AND SEE HOW THIS PLAYS OUT. TEMPS REMAIN AT OR BELOW NORMAL THROUGH THE PERIOD. IF WE HAVE TO PUT UP WITH ALL THE RAIN AND POTENTIAL FLOODING...AT LEAST WE GET COOLER TEMPS OUT OF IT. HOWEVER...THERE IS A LARGER CONCERN THAT WITH THIS CONTINUED WET PATTERN WE COULD BE SETTING THE STAGE FOR SOME REAL PROBLEMS IF WE GET A TROPICAL SYSTEM MOVING IN. TDP && .AVIATION... 06Z UPDATE... TROPICAL MOISTURE PLUME CONTINUES ACROSS THE REGION. MODELS ARE SUPPORTING IFR CIGS AT MANY OF THE AIRPORTS THROUGH EARLY SUNDAY MORNING. THE 00Z NAM SOUNDINGS SUPPORT THIS. IN ADDITION...PATCHY MVFR FOG WILL ALSO BE POSSIBLE. SKIES SHOULD REMAIN MCLDY THROUGH THE DAY WITH CIGS BKN AROUND 035-040. SHRA/TSRA WILL DEVELOP DURING PEAK HEATING. LOW CIGS ARE POSSIBLE AGAIN TOMORROW NIGHT. //ATL CONFIDENCE...06Z UPDATE... HIGH CONFIDENCE FOR WINDS. MEDIUM CONFIDENCE REMAINING ELEMENTS. && .PRELIMINARY POINT TEMPS/POPS... ATHENS 82 70 86 71 / 70 40 50 30 ATLANTA 81 70 84 72 / 70 40 50 30 BLAIRSVILLE 75 67 78 66 / 70 50 60 30 CARTERSVILLE 80 69 86 69 / 70 40 60 30 COLUMBUS 84 73 89 73 / 70 30 50 20 GAINESVILLE 79 68 83 71 / 70 50 60 30 MACON 86 73 88 72 / 70 30 50 20 ROME 80 70 86 70 / 70 50 60 30 PEACHTREE CITY 81 70 84 70 / 70 40 50 30 VIDALIA 89 72 90 73 / 50 20 30 20 && .FFC WATCHES/WARNINGS/ADVISORIES... FLOOD WATCH THROUGH THIS EVENING FOR THE FOLLOWING ZONES: BANKS...BARROW...BARTOW...CARROLL...CATOOSA...CHATTOOGA... CHEROKEE...CLARKE...CLAYTON...COBB...COWETA...DADE...DAWSON... DEKALB...DOUGLAS...FANNIN...FAYETTE...FLOYD...FORSYTH...GILMER... GORDON...GREENE...GWINNETT...HALL...HARALSON...HEARD...HENRY... JACKSON...LUMPKIN...MADISON...MORGAN...MURRAY...NEWTON...NORTH FULTON...OCONEE...OGLETHORPE...PAULDING...PICKENS...POLK... ROCKDALE...SOUTH FULTON...TALIAFERRO...TOWNS...UNION...WALKER... WALTON...WHITE...WHITFIELD...WILKES. && $$ SHORT TERM...NLISTEMAA LONG TERM....TDP AVIATION...NLISTEMAA
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
736 PM EDT MON JUL 8 2013 .SYNOPSIS... ISSUED AT 651 PM EDT MON JUL 8 2013 SHOWER AND THUNDERSTORM COVERAGE WILL INCREASE THROUGH THE EVENING AND INTO THE OVERNIGHT HOURS TONIGHT WITH LOW TEMPERATURES IN THE LOW 70S. THERE IS A CHANCE OF SHOWERS AND THUNDERSTORMS AGAIN ON TUESDAY WITH HIGH TEMPERATURES IN THE UPPER 80S. A FEW OF THE THUNDERSTORMS COULD BE STRONG TO SEVERE. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 314 PM EDT MON JUL 8 2013 COMPLICATED FCST PERIOD WRT CONVECTIVE POTENTIAL THIS EVENING AND AGAIN ON TUESDAY. AREA OF SHOWERS AND THUNDERSTORMS THAT DEVELOPED THIS MORNING ACROSS NE IL HAVE ADVECTED INTO THE NW CWA THIS AFTERNOON. THIS AREA OF SHOWERS APPEARS TO BE IN A DECAYING STATE...AND HAS WORKED OVER THE ENVIRONMENT ACROSS MUCH OF THE AREA. THE DEGREE OF RECOVERY LATE THIS AFTERNOON AND EARLY THIS EVENING WILL BE CRITICAL TO ANY CONVECTIVE POTENTIAL GOING FORWARD INTO THE OVERNIGHT. HI RES MODELS HAVE DONE A POOR JOB WITH THE CONVECTIVE EVOLUTION OVER THE PAST 6 HOURS. HRRR AND 12Z SPC 4KM RUNS HAVE INDICATED A W-E ORIENTED LINE OF CONVECTION DEVELOPING ACROSS THE LOWER GREAT LAKES REGION AND SINKING SOUTHWARD ACROSS THE AREA...COINCIDENT WITH SHORTWAVE ENERGY ADVECTING SOUTHEAST ACROSS THE LOWER GREAT LAKES PER W/V. THE COVERAGE AND EXTENT OF THIS POTENTIAL CONVECTION WILL BE HIGHLY DEPENDENT ON ATMOSPHERIC RECOVERY. RECENT RAP13 RUNS DO INDICATED A STRONG LOW LVL THETA E POOLING ACROSS NRN IL...ADVECTING INTO NRN IN THROUGH 00Z. THIS OPTIMISTIC SCENARIO WOULD ALLOW MLCAPES TO RECOVER TO 1000-2000 J/KG. MODEST 0-6 KM BULK SHEAR VALUES OF 25-30 KTS...AND 850-500 MB LAPSE RATES OF 5.5-6 C/KM WILL KEEP SEVERE POTENTIAL LOW TO MARGINAL AT THIS POINT....HOWEVER AN ISOLATED STORM PRODUCING STRONG TO SEVERE WIND GUSTS IS POSSIBLE. GIVEN ALL OF THESE FACTORS...DECIDED TO LEAVE POPS IN THE SCATTERED CATEGORY TONIGHT...WITH THE BEST POTENTIAL FOR CONVECTION BETWEEN 22Z AND 04Z. CONVECTIVE OUTFLOW SHOULD PUSH PRECIP POTENTIAL SOUTHWARD THROUGH THE OVERNIGHT HOURS...AND HAVE CONFINED SLIGHT CHANCE POPS TO THE SOUTH. WARM AND MUGGY CONDITIONS ARE EXPECTED AGAIN ON TUESDAY WITH HIGHS TOPPING OUT IN THE MID TO UPPER 80S...WITH HEAT INDICES IN THE LOW TO MID 90S. REMNANT CONVECTIVE BOUNDARY MAY BE A FOCUS FOR SHOWER AND THUNDERSTORM ACTIVITY TOMORROW WITH A JUICED ENVIRONMENT. UPSTREAM SHORTWAVE EXPECTED TO ADVECT INTO THE REGION LATE TUESDAY AFTERNOON...WHICH WILL PROVIDE MORE SUPPORT FOR CONVECTION. GIVEN UNCERTAINTY WITH EVOLUTION OF CONVECTION THIS EVENING...AND RESULTING BOUNDARY LOCATION...AS WELL AS UNCERTAINTY WITH THE EVOLUTION OF CONVECTIVELY INDUCED SHORTWAVE...HAVE OPTED TO KEEP POPS IN THE CHANCE RANGE...WITH THE HIGHEST IN THE AFTERNOON. POTENTIAL FOR SEVERE WIND GUSTS TOMORROW DOES EXIST GIVEN HIGHLY UNSTABLE ENVIRONMENT...BUT MODEST BULK SHEAR VALUES OF 25-30 KTS MAY BE A LIMITING FACTOR FOR STORM ORGANIZATION. && .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 314 PM EDT MON JUL 8 2013 SHARPENING MID LVL TROUGH SWEEPING THROUGH SRN CANADA SHRT TERM WILL PROPEL A VIGOROUS CDFNT THROUGH CWA ON WED. IN LIGHT OF DISPARATE MODEL GUIDANCE WILL GENERALLY RELAY ON HIGHRES CONSENSUS OF FASTER FROPA ESP WITHIN GUISE OF TUE NIGHT CONVN/MCS AND LIKELY OUTFLW REMNANT COMPOSITING MORE EFFECTIVE DY3 FORCING MECHANISM SWD TWD THE OH VALLEY. AS SUCH HAVE SHARPLY CURTAILED POPS ON WED. AFT THAT...HIGH PRES TO RIDGE SWD ACRS THE LAKES AS MID LVL TROUGH AMPLIFIES THROUGH NEW ENGLAND BRINGING SEASONABLE TEMPS TO THE REGION AND DRY WX. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING) ISSUED AT 735 PM EDT MON JUL 8 2013 SHOWERS AND THUNDERSTORMS CONTINUE TO FIRE ALONG A SHARP INSTABILITY GRADIENT DRAPED ACROSS OUR AREA. SYNOPTIC FORCING IS WEAK WITH THE MAIN SHORTWAVE NOW EXITING EASTWARD BUT VERY MOIST AND MARGINALLY UNSTABLE CONDITIONS WILL CONTINUE TO SUPPORT CONVECTION THROUGH THE EVENING. A FEW STRONGER STORMS OVER WISCONSIN WILL EVENTUALLY WORK THEIR WAY SOUTH AND MAY IMPACT KSBN BUT THERE HAS ONLY BEEN A FEW LIGHTNING STRIKES AND INSTABILITY WILL ONLY DECREASE ONCE THE SUN SETS. THE MAIN IMPACT WILL BE HEAVY RAIN AND BRIEF MVFR CONDITIONS ARE POSSIBLE IF THESE SHOWERS HIT THE TERMINALS. VERY MOIST BOUNDARY LAYER WILL LIKELY PROMOTE PATCHY FOG BY EARLY TOMORROW MORNING. SURFACE WINDS WILL NOT GO COMPLETELY CALM AND FORECAST SOUNDINGS ARE NOT SUPPORTIVE OF A DENSE FOG EVENT BUT TEMPO IFR CONDITIONS ARE POSSIBLE. MORE SHOWERS AND THUNDERSTORMS EXPECTED TOMORROW IN VERY WARM AND UNSTABLE AIRMASS BUT CONFIDENCE IN EXACT TIMING IS TOO LOW TO INCLUDE A MENTION AT THIS TIME. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ SYNOPSIS...BENTLEY SHORT TERM...NG LONG TERM...T AVIATION...AGD VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV WWW.TWITTER.COM/NWSIWX WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1257 PM MDT SUN JUL 7 2013 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 1254 PM MDT SUN JUL 7 2013 LATEST WV IMAGERY AND RAP ANALYSIS SHOW H5 RIDGE STILL IN PLACE ACROSS SOUTHERN PLAINS WITH SERIES OF WEAK SHORTWAVE TROUGHS ROTATING AROUND WESTERN AND NORTHERN EXTENT OF RIDGE THROUGH WESTERLY FLOW. AT THE SURFACE A COLD FRONT HAS STALLED ALONG THE KS/NE BORDER WITH A SURFACE TROUGH EXTENDING SOUTH ALONG THE KS/CO BORDER. A WEAK SHORTWAVE TROUGH EXPECTED TO DROP SOUTH OUT OF WESTERN NEBRASKA LATE THIS AFTERNOON AND TONIGHT WILL COMBINE WITH THESE SURFACE FEATURES TO INITIATE SCATTERED THUNDERSTORMS ACROSS THE CWA. PRIMARY FOCUS SHOULD BE ALONG FRONT WHERE HIGH TD VALUES NORTH OF THE FRONT HAVE RESULTED IN ML CAPE 1000-1500 J/KG AS OF THE LATEST RAP ANALYSIS. BETTER DEEP SHEER IS EXPECTED TO BE IN PLACE NORTH OF THE FRONT WHERE 0-6KM BULK SHEER AROUND 35KT BY 00Z COULD SUPPORT A SEVERE WIND AND HAIL THREAT. THERE IS LESS INSTABILITY AND MORE CIN TO OVERCOME FURTHER SOUTH ALONG THE SURFACE TROUGH...HOWEVER AS DAYTIME HEATING CONTINUES AND THE SHORTWAVE TROUGH MOVES SOUTH WE SHOULD BE ABLE TO SEE AT LEAST ISOLATED THUNDERSTORMS DEVELOPING ALONG THE SURFACE TROUGH THIS AFTERNOON/EVENING. PWAT VALUES 1.2-1.3" REPRESENT AN ANOMALOUSLY WET ATMOSPHERE FOR THIS TIME OF YEAR...AND AS WAS THE CASE YESTERDAY MANY OF THESE STORMS WILL BE SLOW MOVERS...SO HEAVY RAIN WILL BE A CONCERN WHERE STORMS DEVELOP. LEE TROUGH IS EXPECTED TO BEGIN TO DEEPEN LATE TONIGHT WITH LLJ BUILDING ACROSS THE NE HALF OF THE CWA. WITH INCREASING ISENTROPIC ASCENT AND H85 SUPPORT WE COULD SEE LINGERING THUNDERSTORMS IN PROXIMITY OF THE FRONTAL ZONE ACROSS OUR NE CWA...SO I KEPT ISO THUNDER MENTION MOST OF THE NIGHT FOR THOSE LOCATIONS. THERE IS SOME INDICATION WITH VERY MOIST E-NE BL FLOW OF FOG DEVELOPING IN SW NEBRASKA...HOWEVER WITH BL LIKELY MIXED WITH LLJ INCREASING AND FRONT POSSIBLY SHIFTING NORTH I WASNT CONFIDENT ENOUGH TO ADD MENTION. DESPITE LARGE SCALE FORCING IN PLACE MONDAY IT DOES LOOK LIKE A TROUGH AXIS/DRYLINE ALONG KS/CO BORDER COULD HELP INITIATE THUNDERSTORMS BY THE AFTERNOON WITH INSTABILITY BUILDING ACROSS THE EASTERN CWA. I WASNT CONFIDENT ENOUGH TO ADD MORE THAN SLIGHT CHANCE MENTION AT THIS POINT. H85 TEMPS ARE ACTUALLY ADVERTISED TO BE 2-3C WARMER THAN THE LAST FEW DAYS WHEN HIGHS HAVE BEEN AROUND 100F...SO WE COULD BE LOOKING AT NEAR RECORD HIGH TEMPS ACROSS THE CWA MONDAY WITH VALUES IN THE 100S ACROSS THE AREA. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 1251 PM MDT SUN JUL 7 2013 AN UPPER RIDGE CENTERED OVER THE SOUTHERN ROCKIES WILL BE THE DOMINATING INFLUENCE THROUGH THE LONG TERM PERIOD. TEMPERATURES WILL BE ABOVE NORMAL...ALTHOUGH A WEAK COLD FRONT ON TUESDAY WILL KNOCK TEMPERATURES DOWN A FEW DEGREES THROUGH THURSDAY...THEY WILL WARM AGAIN FOR THE LATE WEEK AND WEEKEND. POSITION OF THE RIDGE EARLY IN THE PERIOD WILL BE CLOSER TO THE FOUR CORNERS AND ALLOW SHORTWAVE TROUGHS ROTATING AROUND IT TO BRING A CHANCE FOR SCATTERED THUNDERSTORMS. AS THE RIDGE BUILDS EASTWARD LATER IN THE WEEK...THUNDERSTORM CHANCES WILL BECOME MORE ISOLATED. SEVERE WEATHER IS NOT ANTICIPATED WITH THE WEAK FLOW ALOFT LIMITING UPDRAFT ORGANIZATION. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 1110 AM MDT SUN JUL 7 2013 VFR CONDITIONS AND WINDS GENERALLY LESS THAN 12KT SHOULD PERSIST AT BOTH KGLD AND KMCK TERMINALS THROUGH THE TAF PERIOD. WIND DIRECTION WILL GENERALLY KEEP AN EASTERLY COMPONENT THROUGH THE TAF PERIOD...THOUGH IT WILL BE SOMEWHAT ERRATIC DUE TO THUNDERSTORM ACTIVITY AND FRONTAL POSITIONS. A STALLED FRONT ALONG THE KS/CO BORDER WILL ACT AS A FOCUS FOR SCATTERED THUNDERSTORM DEVELOPMENT THIS AFTERNOON/EVENING...WITH ACTIVITY POSSIBLY LINGERING AT KMCK LATER THAN KGLD AS A DISTURBANCE PASSES TO THE NORTH AND EAST. THERE IS SOME INDICATION BY MODELS OF MVFR VIS BY SUNRISE MON WITH LIGHT FOG DEVELOPING AS A RESULT OF MOIST EASTERLY FLOW NORTH OF THIS FRONT. WITH LLJ INCREASING BOUNDARY LAYER MIXING OVER KGLD/KMCK AND FRONT BEGINNING TO SHIFT TO THE NORTH AND WEST I AM NOT CONFIDENT ENOUGH TO ADD THIS TO TAFS. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...DJR LONG TERM...024 AVIATION...DR
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1255 PM MDT SUN JUL 7 2013 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 1254 PM MDT SUN JUL 7 2013 LATEST WV IMAGERY AND RAP ANALYSIS SHOW H5 RIDGE STILL IN PLACE ACROSS SOUTHERN PLAINS WITH SERIES OF WEAK SHORTWAVE TROUGHS ROTATING AROUND WESTERN AND NORTHERN EXTENT OF RIDGE THROUGH WESTERLY FLOW. AT THE SURFACE A COLD FRONT HAS STALLED ALONG THE KS/NE BORDER WITH A SURFACE TROUGH EXTENDING SOUTH ALONG THE KS/CO BORDER. A WEAK SHORTWAVE TROUGH EXPECTED TO DROP SOUTH OUT OF WESTERN NEBRASKA LATE THIS AFTERNOON AND TONIGHT WILL COMBINE WITH THESE SURFACE FEATURES TO INITIATE SCATTERED THUNDERSTORMS ACROSS THE CWA. PRIMARY FOCUS SHOULD BE ALONG FRONT WHERE HIGH TD VALUES NORTH OF THE FRONT HAVE RESULTED IN ML CAPE 1000-1500 J/KG AS OF THE LATEST RAP ANALYSIS. BETTER DEEP SHEER IS EXPECTED TO BE IN PLACE NORTH OF THE FRONT WHERE 0-6KM BULK SHEER AROUND 35KT BY 00Z COULD SUPPORT A SEVERE WIND AND HAIL THREAT. THERE IS LESS INSTABILITY AND MORE CIN TO OVERCOME FURTHER SOUTH ALONG THE SURFACE TROUGH...HOWEVER AS DAYTIME HEATING CONTINUES AND THE SHORTWAVE TROUGH MOVES SOUTH WE SHOULD BE ABLE TO SEE AT LEAST ISOLATED THUNDERSTORMS DEVELOPING ALONG THE SURFACE TROUGH THIS AFTERNOON/EVENING. PWAT VALUES 1.2-1.3" REPRESENT AN ANOMALOUSLY WET ATMOSPHERE FOR THIS TIME OF YEAR...AND AS WAS THE CASE YESTERDAY MANY OF THESE STORMS WILL BE SLOW MOVERS...SO HEAVY RAIN WILL BE A CONCERN WHERE STORMS DEVELOP. LEE TROUGH IS EXPECTED TO BEGIN TO DEEPEN LATE TONIGHT WITH LLJ BUILDING ACROSS THE NE HALF OF THE CWA. WITH INCREASING ISENTROPIC ASCENT AND H85 SUPPORT WE COULD SEE LINGERING THUNDERSTORMS IN PROXIMITY OF THE FRONTAL ZONE ACROSS OUR NE CWA...SO I KEPT ISO THUNDER MENTION MOST OF THE NIGHT FOR THOSE LOCATIONS. THERE IS SOME INDICATION WITH VERY MOIST E-NE BL FLOW OF FOG DEVELOPING IN SW NEBRASKA...HOWEVER WITH BL LIKELY MIXED WITH LLJ INCREASING AND FRONT POSSIBLY SHIFTING NORTH I WASNT CONFIDENT ENOUGH TO ADD MENTION. DESPITE LARGE SCALE FORCING IN PLACE MONDAY IT DOES LOOK LIKE A TROUGH AXIS/DRYLINE ALONG KS/CO BORDER COULD HELP INITIATE THUNDERSTORMS BY THE AFTERNOON WITH INSTABILITY BUILDING ACROSS THE EASTERN CWA. I WASNT CONFIDENT ENOUGH TO ADD MORE THAN SLIGHT CHANCE MENTION AT THIS POINT. H85 TEMPS ARE ACTUALLY ADVERTISED TO BE 2-3C WARMER THAN THE LAST FEW DAYS WHEN HIGHS HAVE BEEN AROUND 100F...SO WE COULD BE LOOKING AT NEAR RECORD HIGH TEMPS ACROSS THE CWA MONDAY WITH VALUES IN THE 100S ACROSS THE AREA. .LONG TERM...(WEDNESDAY THROUGH SUNDAY) ISSUED AT 227 AM MDT SUN JUL 7 2013 LONG RANGE MODEL FORECAST INDICATES RIDGE PATTERN INCREASING IN AMPLITUDE OVER THE FOUR CORNERS REGION FOR WEDNESDAY AND CONTINUING TO BE PRESENT THROUGHOUT THE ENTIRE EXTENDED PERIOD. 500 MB HEIGHTS WILL CONTINUE TO INCREASE IN MAGNITUDE INTO NEXT WEEKEND...INDICATING THE INCREASING STRENGTH OF THE UPPER LEVEL HIGH. THE UPPER LEVEL JET STREAM LOOKS TO STAY WELL TO THE NORTH THROUGHOUT THE ENTIRE PERIOD. A SURFACE LOW PRESSURE SYSTEM WILL STAY IN PLACE OVER THE TRI STATE AREA THROUGHOUT THE PERIOD WITH STRONG WARM AIR ADVECTION MOVING INTO THE HIGH PLAINS. TEMPERATURES LOOK TO BE IN THE MID 90S FOR WEDNESDAY AND THURSDAY...INCREASING TO THE UPPER 90S TO LOW 100S ACROSS THE REGION FOR THE WEEKEND. BEST CHANCE FOR PRECIPITATION WILL BE WEDNESDAY EVENING AND OVERNIGHT AS STRONG SURFACE CONVERGENCE WILL HELP WITH THUNDERSTORM ACTIVITY. ISOLATED CHANCES FOR THUNDERSTORM ACTIVITY WILL BE PRESENT MOSTLY FOR THE EASTERN COUNTIES IN THE CWA FOR THURSDAY AND INTO NEXT WEEKEND. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 1110 AM MDT SUN JUL 7 2013 VFR CONDITIONS AND WINDS GENERALLY LESS THAN 12KT SHOULD PERSIST AT BOTH KGLD AND KMCK TERMINALS THROUGH THE TAF PERIOD. WIND DIRECTION WILL GENERALLY KEEP AN EASTERLY COMPONENT THROUGH THE TAF PERIOD...THOUGH IT WILL BE SOMEWHAT ERRATIC DUE TO THUNDERSTORM ACTIVITY AND FRONTAL POSITIONS. A STALLED FRONT ALONG THE KS/CO BORDER WILL ACT AS A FOCUS FOR SCATTERED THUNDERSTORM DEVELOPMENT THIS AFTERNOON/EVENING...WITH ACTIVITY POSSIBLY LINGERING AT KMCK LATER THAN KGLD AS A DISTURBANCE PASSES TO THE NORTH AND EAST. THERE IS SOME INDICATION BY MODELS OF MVFR VIS BY SUNRISE MON WITH LIGHT FOG DEVELOPING AS A RESULT OF MOIST EASTERLY FLOW NORTH OF THIS FRONT. WITH LLJ INCREASING BOUNDARY LAYER MIXING OVER KGLD/KMCK AND FRONT BEGINNING TO SHIFT TO THE NORTH AND WEST I AM NOT CONFIDENT ENOUGH TO ADD THIS TO TAFS. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...DR LONG TERM...MK AVIATION...DR
AREA FORECAST DISCUSSION
NWS GOODLAND KS
229 AM MDT SUN JUL 7 2013 .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 1251 PM MDT SAT JUL 6 2013 LATEST WV IMAGERY AND RAP H5 ANALYSIS SHOW H5 RIDGE STILL IN PLACE ACROSS SOUTHERN PLAINS...WITH WESTERLY FLOW ACROSS THE NORTHERN PLAINS. SURFACE TROUGH IS CURRENTLY IN PLACE ACROSS WESTERLY NEBRASKA EXTENDING SOUTH ACROSS NW KS AND SE CO. DESPITE LITTLE BEING APPARENT IN THE 500 MB HEIGHT FIELD BEYOND SOME WEAK RIPPLES WV IMAGERY AND PV/VORT FIELDS CONTINUE TO INDICATE VIGOROUS SHORTWAVE ACTIVITY ROTATING AROUND THE NORTHERN PART OF THE RIDGE. ONE SUCH FEATURE IS PROGGED TO PASS OVER OUR CWA BY THIS EVENING...WHICH SHOULD HELP INCREASE THUNDERSTORM CHANCES ACROSS THE REGION. I COULDNT RULE OUT BETTER COVERAGE THAN THE LAST FEW NIGHTS WITH SURFACE TROUGH POSSIBLY ACTING TO AID THUNDERSTORM INITIATION AS SHORTWAVE PASSES THROUGH THE REGION. I STILL EXPECT ACTIVITY TO INITIALLY START OVER HIGHER TERRAIN THIS AFTERNOON AND BEGIN TO SPREAD EAST WITH SHORTWAVE. LATEST HRRR/RAP SUPPORT THIS ACTIVITY INCREASING IN COVERAGE BY 00-03Z AS THIS INTERACTS WITH SHORTWAVE TROUGH AXIS AND BETTER INSTABILITY ACROSS THE CENTRAL/EASTERN PART OF CWA. THERE IS SOME LINGERING ELEVATED INSTABILITY OVERNIGHT...HOWEVER LLJ IS EAST OF CWA ALONG WITH BEST ISOTROPIC SUPPORT...SO BEYOND SOME LINGERING SHOWERS/T-STORMS WITH SHORTWAVE LATE TONIGHT IN THE EAST WITH SHORTWAVE I THINK MOST OF THIS ACTIVITY WILL BE TAPERING OFF FAIRLY QUICKLY AFTER SUNSET. HODOGRAPHS/SHEER PROFILES ARE RELATIVELY WEAK AND WITH MARGINAL CAPE I AM NOT SURE WE WOULD SEE MUCH OF A SEVERE HAIL RISK. INVERTED V TYPE SOUNDINGS AND DCAPE VALUES IN THE 500-1500 J/KG RANGE RAISE CONCERNS FOR SEVERE GUST POTENTIAL WITH ANY COLLAPSING UPDRAFTS...SO THIS WILL NEED TO BE MONITORED. WITH LITTLE CHANGING REGARDING LARGE SCALE PATTERN AND MODELS INDICATING POSSIBLE EARLIER INITIATION SUN I KEPT MENTION OF THUNDERSTORM CHANCES SUNDAY AFTERNOON...WITH ONLY MINOR ADJUSTMENTS TO TIMING. HOT AIRMASS WILL STILL BE IN PLACE SUN...WITH EXPECTED CLOUD COVER THE ONE LIMITING FACTOR. FEWER CLOUDS...AND WE SHOULD AGAIN SEE HIGHS APPROACH 100F ACROSS THE ENTIRE AREA. .LONG TERM...(WEDNESDAY THROUGH SUNDAY) ISSUED AT 227 AM MDT SUN JUL 7 2013 LONG RANGE MODEL FORECAST INDICATES RIDGE PATTERN INCREASING IN AMPLITUDE OVER THE FOUR CORNERS REGION FOR WEDNESDAY AND CONTINUING TO BE PRESENT THROUGHOUT THE ENTIRE EXTENDED PERIOD. 500 MB HEIGHTS WILL CONTINUE TO INCREASE IN MAGNITUDE INTO NEXT WEEKEND...INDICATING THE INCREASING STRENGTH OF THE UPPER LEVEL HIGH. THE UPPER LEVEL JET STREAM LOOKS TO STAY WELL TO THE NORTH THROUGHOUT THE ENTIRE PERIOD. A SURFACE LOW PRESSURE SYSTEM WILL STAY IN PLACE OVER THE TRI STATE AREA THROUGHOUT THE PERIOD WITH STRONG WARM AIR ADVECTION MOVING INTO THE HIGH PLAINS. TEMPERATURES LOOK TO BE IN THE MID 90S FOR WEDNESDAY AND THURSDAY...INCREASING TO THE UPPER 90S TO LOW 100S ACROSS THE REGION FOR THE WEEKEND. BEST CHANCE FOR PRECIPITATION WILL BE WEDNESDAY EVENING AND OVERNIGHT AS STRONG SURFACE CONVERGENCE WILL HELP WITH THUNDERSTORM ACTIVITY. ISOLATED CHANCES FOR THUNDERSTORM ACTIVITY WILL BE PRESENT MOSTLY FOR THE EASTERN COUNTIES IN THE CWA FOR THURSDAY AND INTO NEXT WEEKEND. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 1100 PM MDT SAT JUL 6 2013 VFR EXPECTED AT KGLD AND KMCK THROUGH THE PERIOD. SFC TROUGH WITH LGT/VRB WINDS TO LINGER NEAR BOTH TERMINALS THROUGH 15-17Z BEFORE BECOMING EASTERLY THEN SOUTHEASTERLY AT 10KTS OR SO. AS HAS BEEN THE CASE THE PAST FEW DAYS SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE DURING THE LATE AFTERNOON AND EVENING HOURS. PINPOINTING WHETHER OR NOT THEY WILL DIRECTLY IMPACT EITHER TERMINAL RATHER DIFFICULT AND FOR NOW NOT INCLUDE A MENTION IN EITHER TAF. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...DR LONG TERM...MK AVIATION...99
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1101 PM MDT SAT JUL 6 2013 .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 1251 PM MDT SAT JUL 6 2013 LATEST WV IMAGERY AND RAP H5 ANALYSIS SHOW H5 RIDGE STILL IN PLACE ACROSS SOUTHERN PLAINS...WITH WESTERLY FLOW ACROSS THE NORTHERN PLAINS. SURFACE TROUGH IS CURRENTLY IN PLACE ACROSS WESTERLY NEBRASKA EXTENDING SOUTH ACROSS NW KS AND SE CO. DESPITE LITTLE BEING APPARENT IN THE 500 MB HEIGHT FIELD BEYOND SOME WEAK RIPPLES WV IMAGERY AND PV/VORT FIELDS CONTINUE TO INDICATE VIGOROUS SHORTWAVE ACTIVITY ROTATING AROUND THE NORTHERN PART OF THE RIDGE. ONE SUCH FEATURE IS PROGGED TO PASS OVER OUR CWA BY THIS EVENING...WHICH SHOULD HELP INCREASE THUNDERSTORM CHANCES ACROSS THE REGION. I COULDNT RULE OUT BETTER COVERAGE THAN THE LAST FEW NIGHTS WITH SURFACE TROUGH POSSIBLY ACTING TO AID THUNDERSTORM INITIATION AS SHORTWAVE PASSES THROUGH THE REGION. I STILL EXPECT ACTIVITY TO INITIALLY START OVER HIGHER TERRAIN THIS AFTERNOON AND BEGIN TO SPREAD EAST WITH SHORTWAVE. LATEST HRRR/RAP SUPPORT THIS ACTIVITY INCREASING IN COVERAGE BY 00-03Z AS THIS INTERACTS WITH SHORTWAVE TROUGH AXIS AND BETTER INSTABILITY ACROSS THE CENTRAL/EASTERN PART OF CWA. THERE IS SOME LINGERING ELEVATED INSTABILITY OVERNIGHT...HOWEVER LLJ IS EAST OF CWA ALONG WITH BEST ISOTROPIC SUPPORT...SO BEYOND SOME LINGERING SHOWERS/T-STORMS WITH SHORTWAVE LATE TONIGHT IN THE EAST WITH SHORTWAVE I THINK MOST OF THIS ACTIVITY WILL BE TAPERING OFF FAIRLY QUICKLY AFTER SUNSET. HODOGRAPHS/SHEER PROFILES ARE RELATIVELY WEAK AND WITH MARGINAL CAPE I AM NOT SURE WE WOULD SEE MUCH OF A SEVERE HAIL RISK. INVERTED V TYPE SOUNDINGS AND DCAPE VALUES IN THE 500-1500 J/KG RANGE RAISE CONCERNS FOR SEVERE GUST POTENTIAL WITH ANY COLLAPSING UPDRAFTS...SO THIS WILL NEED TO BE MONITORED. WITH LITTLE CHANGING REGARDING LARGE SCALE PATTERN AND MODELS INDICATING POSSIBLE EARLIER INITIATION SUN I KEPT MENTION OF THUNDERSTORM CHANCES SUNDAY AFTERNOON...WITH ONLY MINOR ADJUSTMENTS TO TIMING. HOT AIRMASS WILL STILL BE IN PLACE SUN...WITH EXPECTED CLOUD COVER THE ONE LIMITING FACTOR. FEWER CLOUDS...AND WE SHOULD AGAIN SEE HIGHS APPROACH 100F ACROSS THE ENTIRE AREA. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 1255 PM MDT SAT JUL 6 2013 AN UPPER RIDGE CENTERED OVER THE CENTRAL AND SOUTHERN ROCKIES WILL BE THE DOMINATING INFLUENCE IN THE LONG TERM PERIOD. TEMPERATURES WILL BE ABOVE NORMAL THE ENTIRE PERIOD...WITH THE HOTTEST DAYS BEING FRIDAY AND SATURDAY. A WEAK COLD FRONT WILL MOVE THROUGH TUESDAY AND TUESDAY NIGHT WITH SLIGHTLY COOLER TEMPERATURES IN ITS WAKE. THERE WILL BE SEVERAL OPPORTUNITIES FOR SCATTERED THUNDERSTORMS ASSOCIATED WITH WEAK SHORTWAVE TROUGHS ROTATING AROUND THE RIDGE...BUT WITH THE WEAK FLOW ALOFT SEVERE WEATHER IS NOT ANTICIPATED. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 1100 PM MDT SAT JUL 6 2013 VFR EXPECTED AT KGLD AND KMCK THROUGH THE PERIOD. SFC TROUGH WITH LGT/VRB WINDS TO LINGER NEAR BOTH TERMINALS THROUGH 15-17Z BEFORE BECOMING EASTERLY THEN SOUTHEASTERLY AT 10KTS OR SO. AS HAS BEEN THE CASE THE PAST FEW DAYS SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE DURING THE LATE AFTERNOON AND EVENING HOURS. PINPOINTING WHETHER OR NOT THEY WILL DIRECTLY IMPACT EITHER TERMINAL RATHER DIFFICULT AND FOR NOW NOT INCLUDE A MENTION IN EITHER TAF. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...DR LONG TERM...024 AVIATION...99
AREA FORECAST DISCUSSION...UPDATED
NWS GRAY ME
1041 PM EDT MON JUL 8 2013 .SYNOPSIS... WEAK LOW PRESSURE WILL MOVE ACROSS NEW ENGLAND TONIGHT KEEPING UNSETTLED CONDITIONS ACROSS THE AREA. COOL EASTERLY FLOW WILL KEEP CONDITIONS COOL AND CLOUDY FOR MUCH OF TUESDAY. A WARM FRONT WILL PUSH SLOWLY NORTH ACROSS NEW ENGLAND ON WEDNESDAY. A COLD FRONT WILL APPROACH FROM THE WEST THURSDAY THEN SLOWLY DRIFT ACROSS NEW ENGLAND THURSDAY NIGHT THEN MOVE OFFSHORE ON FRIDAY. THIS COLD FRONT WILL CONTINUE TO SLOWLY MOVE OUT TO SEA OVER THE WEEKEND AS WEAK HIGH PRESSURE BUILDS IN FROM THE WEST. && .NEAR TERM /UNTIL 8 AM TUESDAY MORNING/... UPDATE...00Z HRRR CONTINUES TO HAVE A GOOD HANDLE ON CURRENT LOCATIONS OF SHRA. HAVE USED ITS POP GRIDS TO TREND THE NEXT 6 HOURS OF THE FORECAST...AS SHRA SLOWLY MEANDER INTO WRN ME. IT HAS ALSO BACKED OFF THE COASTAL STRATUS FOR A FEW HOURS...WAITING UNTIL AFTER 09Z TO CREEP INTO COASTAL ME. WILL PROBABLY BE AMENDING TAFS TO ACCOUNT FOR THE DELAYED TIMING. PREVIOUS DISCUSSION...FLASH FLOOD WATCH REMAINS IN EFFECT THROUGH MIDNIGHT...ALTHOUGH CONVECTION THIS AFTERNOON HAS BEEN MORE SPARSE THAN EXPECTED. EASTERLY FLOW SPREADING ACROSS MAINE AND SOUTHEASTERN NEW HAMPSHIRE THIS AFTERNOON HAS SUPPRESSED CONVECTIVE ACTIVITY. MODEST INSTABILITY DOES STILL EXIST ACROSS THE AREA SO WE ARE HESITANT TO TAKE DOWN A WATCH AT THIS HOUR. MEANWHILE DEW POINT TEMPERATURES ACROSS MAINE AND COASTAL NEW HAMPSHIRE HAVE FALLEN THROUGH THE 60S WITH SOME UPPER 50S AT THE TIME OF THIS WRITING. EXPECT SHOWERS FIRING IN NEW HAMPSHIRE TO SPREAD EASTWARD INTO SOUTHERN MAINE LATE THIS EVENING THEN PUSH SOUTHWARD TOWARD DAYBREAK. PATCHY FOG AND PERHAPS SOME DRIZZLE LATE TONIGHT AS WELL GIVEN THE EASTERLY NEAR-SURFACE FLOW. && .SHORT TERM /8 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/... LOW CLOUDS AND COOL TEMPERATURES WILL BE THE RULE FOR TUESDAY AS LIGHT EASTERLY WINDS KEEP A WEAK SHORTWAVE RIDGE FROM CLEARING SKIES. WITH LOWER HUMIDITIES IT WILL FEEL MORE LIKE SEPTEMBER ACROSS THE REGION. LOW PRECIPITATION CHANCES UNDER THE WEAK RIDGE. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... AN UPPER LEVEL TROUGH CARVES OUT ACROSS THE UPPER MIDWEST AND GREAT LAKES REGION ON WEDNESDAY AS IT ALSO SLOWLY SHIFTS TO THE EAST. THIS SETS UP AN INCREASINGLY VERY WARM AND HUMID SOUTHWEST FLOW ALOFT AS THE TEMPERATURES AT 850 MILLIBARS CLIMB ABOVE 15 CELSIUS AT 12Z WEDNESDAY AND CONTINUE THROUGH THURSDAY AS THE UPPER LEVEL TROUGH SLOWLY WORKS ITS WAY TO THE EAST COAST. AT THE SURFACE A WARM FRONT MOVES SLOWLY TO THE NORTHEAST ACROSS THE REGION AS THE VERY WARM AND HUMID AIR MOVES IN. THIS IS FOLLOWED BY A SLOW MOVING COLD FRONT MOVING IN FROM THE WEST ON THURSDAY. THE FRONT TAKES ITS TIME DRIFTING OFF THE COAST THURSDAY NIGHT AND FRIDAY AS THE UPPER LEVEL TROUGH BEGINS TO CUTOFF AND STALL ALONG THE EASTERN SEABOARD. THIS SLOW MOVING SYSTEM WILL MEAN A PERIOD OF SHOWERS AND ISOLATED TO SCATTERED THUNDERSTORMS WEDNESDAY THROUGH THURSDAY. SCATTERED SHOWERS LINGER INTO FRIDAY. THE UPPER LEVEL CUTOFF WEAKENS AS THE SURFACE COLD FRONT MOVES OUT TO SEA SATURDAY THROUGH MONDAY AS WEAK HIGH PRESSURE BUILDS IN FROM THE WEST. DRIER WEATHER GRADUALLY OVERTAKES THE REGION BUT STILL A SLIGHT CHANCE OF SHOWERS WILL HOLD ON. GENERALLY USED BLEND OF GFS/NAM/MET/MAV/HPC QPF FOR PERIODS 4 AND 5 THEN GFS40/GMOS/MEX FOR THE REST OF THE LONG TERM FCST. && .AVIATION /03Z TUESDAY THROUGH SATURDAY/... SHORT TERM...EXPECT NEARLY ALL AREAS TO LOWER TO MVFR WITH IFR IN FOG AND RAIN OVERNIGHT. MVFR CONDITIONS AGAIN TUESDAY IN LOW CLOUDS AND DISSIPATING FOG. SOME IMPROVEMENT LATE TUESDAY UNDER SHORTWAVE RIDGE. LONG TERM /WEDNESDAY THROUGH SATURDAY/...IFR IN SHOWERS AND POSSIBLE THUNDERSTORMS WEDNESDAY THROUGH THURSDAY THEN MVFR/IFR POSSIBLE IN SCATTERED SHOWERS FRIDAY THROUGH SATURDAY. && .MARINE... SHORT TERM...LIGHT EASTERLY WINDS THROUGH TUESDAY NIGHT WILL RESULT IN 2 TO 4 FOOT SEAS IN THE OUTER WATERS. NO HEADLINES EXPECTED. VISIBILITY COULD BE REDUCED IN FOG AND DRIZZLE. LONG TERM /WEDNESDAY THROUGH SATURDAY/...WINDS AND SEAS STAY BELOW SCA LEVELS THROUGH THE LONG TERM FORECAST PERIOD. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...NONE. NH...NONE. MARINE...NONE. && $$ NEAR TERM...LEGRO
AREA FORECAST DISCUSSION...UPDATED
NWS PITTSBURGH PA
810 PM EDT MON JUL 8 2013 .SYNOPSIS... WARM AND HUMID WEATHER WITH A CHANCE OF A SHOWER OR THUNDERSTORM WILL CONTINUE THROUGH MIDWEEK. A COLD FRONT WILL APPROACH THE AREA BY LATE WEDNESDAY INTO THURSDAY WITH A BETTER CHANCE OF SHOWERS AND STORMS. COOLER AND DRIER AIR WILL FILTER INTO THE REGION BEHIND THE FRONT. && .NEAR TERM /THROUGH TUESDAY/... AS SUGGESTED BY RECENT HI-RES MODEL RUNS...ONGOING CNVCTN OVER OH HAS SHOWN WEAKENING TREND AS IT PROGRESSES EWD. POPS WERE ADJUSTED TO REFLECT THE PCPN MOVG INTO WRN ZONES THRU EARLY EVE. A SECOND SHRTWV TROF WILL INVIGORATE CNVCTN LATE TNGT...WHICH IS XPCD TO MOVE THRU THE FCST AREA THRU TUE MRNG. THESE SHWRS AND TSTMS WILL BE FED BY AN AMPLE FETCH OF LOW-LVL MSTR CHARACTERIZED BY DEWPTS IN THE LOW 70S. WITH DEPARTURE OF CNVCTN IN THE MRNG...SOME BREAKS IN CLD CVR XPCD BY LATE MRNG OR EARLY AFTN...WHICH WILL CONTRIBUTE TO POTL FOR DESTABILIZATION VIA HEATING OF VERY MST BNDRY LYR. THIS PSBLTY IS MOST LKLY IN WRN AND NWRN CTYS...WHERE BRF SHRTWV RDGG XPCD IN WAKE OF MRNG CNVCTN. THERE IS A CONDITIONAL THREAT OF SVR WX TUE AFTN IF THE MDT INSTBY SHOWN IN THE LATEST NAM RUN IS REALIZED AND ABLE TO OVERCOME THE RELATIVELY MODEST SHEAR. SVR THREAT WOULD BE MAINLY FROM WET MICROBURSTS. OWING TO MRNG CNVCTN AND LINGERING CLD CVR...CONTD IDEA FROM PREV FCST OF SLGTLY COOLER MAXIMA. LWR 80S XPCD GENLY IN ERN ZONES... WITH MID 80S XPCD IN WRN ZONES...WHERE SOME INSOLATION PSBL. PREV DISCUSSION FOLLOWS... HIGH RESOLUTION MODELS INDICATE BASICALLY EXACTLY WHAT HAS BEEN OCCURRING LATE THIS MORNING AND VERY EARLY AFTERNOON...THAT CONVECTIVE TRENDS SHOULD BE DOWNWARD ACROSS THE AREA. THE MID- LEVEL LOW IS DEPARTING TO THE EAST...AND LIKELY WITH IT THE MID- LEVEL COLD POOL INDUCED INSTABILITY THAT WAS ALLOWING FOR BETTER SHOWER/THUNDERSTORM COVERAGE EARLIER TODAY. AS SUCH...SHOWER CHANCES HAVE BEEN ROLLED BACK ACROSS THE AREA TO NOTHING MORE THAN ISOLATED ANYWHERE. A FAIRLY PRONOUNCED AND STILL STRENGTHENING SHORT WAVE TROUGH IS MOVING THROUGH THE UPPER GREAT LAKES AT THE MOMENT...WITH WIDESPREAD SHOWERS AND EMBEDDED THUNDERSTORMS ASSOCIATED WITH IT. BOTH HIGH RESOLUTION AS WELL AS LARGE SCALE MODELS HAVE A GOOD HANDLE ON THIS SYSTEM...TRACKING IT TOWARD OUR WESTERN COUNTIES BY ROUGHLY 00Z THIS EVENING...AND ACROSS THE REST OF THE AREA THIS EVENING AND OVERNIGHT. POPS WERE ALREADY HIGH IN THE FORECAST...AND THESE HIGH POPS WERE MAINTAINED AS THE SYSTEM TRACKS ACROSS THE FORECAST AREA THROUGH THE NIGHT. AS TONIGHT`S SYSTEM DEPARTS TO THE EAST BY LATE MORNING/AFTERNOON TUESDAY...FORCING FOR ASCENT REALLY DIMINISHES. AT LEAST SOME CLEARING SHOULD BE EVIDENT BEHIND THAT SYSTEM GIVEN SUBSIDENCE AND A BIT OF LAYER DRYING. AS SUCH...BREAKS IN THE CLOUDS SHOULD ALLOW FOR TEMPERATURES TO RUN UP RATHER QUICKLY WHENEVER/WHEREVER THE SUN DOES COME OUT. WHILE THE AREA AS A WHOLE WILL LIKELY STICK IN THE 80S...A VERY MOIST BOUNDARY LAYER WITH DEWPOINTS IN THE LOWER 70S ON A WIDESPREAD BASIS WILL MAKE TUESDAY A VERY UNCOMFORTABLE DAY. FRIES && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/... H5 FLOW INITIALLY STARTS ZONAL AT BEGINNING THIS FORECAST PERIOD. HOWEVER...UPPER LEVEL WAVE WILL DEEPEN TROF FROM CANADIAN PLAINS THROUGH MIDWEST AND THIS WILL SUPPORT SURFACE COLD FRONT WHICH WILL PUSH THROUGH CWA LATE WEDNESDAY. IN ADVANCE...CONVECTION TO DEVELOP OR POSSIBLY BE ONGOING IN ADVANCE OF FRONT. APPEARS PLENTY OF MOISTURE WITH SFC TD/S UPPER 60S TO AROUND 70 AND PW/S 1.5+. MODELS HAVE GOOD DEAL OF MOISTURE PROJECTED IN LOWER AND MID- TROPOSPHERE AND IF ENOUGH CLOUDINESS...COULD HINDER INSTABILITY. IN THOSE AREAS WITH LESS CLOUDS CAPE COULD REACH 1000-2000 OR SO. SHEAR SEEMS A BIT LACKING AT THIS TIME WITH BULK SHEAR ABOUT 30 KTS. ALSO...AT THIS TIME CALIBRATED SEVERE FIELD FROM SREF MODEST AT BEST WITH RATHER LOW PROBABILITIES. MOST LIKELY BECAUSE PREDICTED LACK OF SIGNIFICANT SHEAR. WILL CONTINUE TO MONITOR FOR POTENTIAL. POSSIBLY SOME LINGERING SHOWERS EARLY THURSDAY. HOWEVER...AS FRONT CONTINUES SOUTHEAST...DRIER AND COOLER AIR TO MOVE INTO REGION BY LATER THURSDAY AND INTO THURSDAY NIGHT. SMALL FLY IN THE OINTMENT AT THIS TIME IS THAT GFS CUTS OFF H5 LOW WHICH COULD RETARD STRENGTH OF CLEARING. ECMWF SLOWER WITH H5 LOW AND DEVELOPS IT MUCH LATER. SIGNIFICANT UNCERTAINTY AT THIS TIME ON H5 LOW DEVELOPMENT AND TIMING. && .LONG TERM /FRIDAY THROUGH MONDAY/... FRONT WILL SLOWLY CROSS THE REGION WED NIGHT. SHIFTING HIGHEST POPS FROM NORTH TO SOUTH. COOLER AND LESS HUMID AIR ARRIVES BY WEEKS END...HWVR THE BIG QUESTION IS WHAT HAPPENS TO H5 CYCLONE ONCE IT CROSSES THE REGION? GFS TAKES IT SW INTO THE GULF COAST STATES...WHILE ECMWF LIFTS IT NE AND DEVELOPS A STRONG MID LVL ANTICYCLONE ACRS THE GULF COAST. && .AVIATION /00Z TUESDAY THROUGH TUESDAY NIGHT/... SHORT WAVE SUPPORTING SHOWERS AND THUNDERSTORMS CURRENTLY WESTERN LAKE ERIE THROUGH CENTRAL OH. PROGRESSION EAST ABOUT 20 KTS. MODELS TEND TO DIMINISH FIRST WAVE OF PRECIP AND THEN SUBSEQUENT SWATH COMES THROUGH A LITTLE LATER WITH BULK OF PRECIP BETWEEN 06Z TO 13Z OR SO. INSERTED SOME BR BY MORNING. ALSO...SEVERAL TERMINALS OPTED TO GO WITH PREVAILING 5-6SM -SHRA AND THEN VCTS. HRRR NOT ADVERTISING WIDESPREAD IFR ST/SC CEILINGS EITHER DURING OR IN WAKE OF PRECIPITATION SHIELD. AS A RESULT, OPTED TO GO MVFR MOST TERMINALS. WINDS OUTSIDE ANY CONVECTION GENERALLY LIGHT AND FROM THE SOUTHWEST 190-240 DEGREES AT 4 TO 7 KTS. OUTLOOK.../TUESDAY NIGHT THROUGH FRIDAY/... MOSTLY ZONAL FLOW BY TUESDAY NIGHT...HOWEVER...EMBEDDED WAVES WILL TRIGGER SOME SCT CONVECTION TUESDAY NIGHT. AT THIS TIME BETTER CHANCE FOR WIDER COVERAGE AND STRONGER STORMS WOULD BE ON WEDNESDAY AS STRONGER WAVE DIVES SE FROM CANADA. COLD FRONT TO PASS CWA BY MIDDAY THURSDAY AND COOLER AND DRIER AIR TO FILTER INTO REGION. RESTRICTIONS ON WEDNESDAY INTO THURSDAY MORNING...THEN VFR. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$ KRAMAR/FRIES/KANE
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
131 PM EDT SUN JUL 7 2013 .SYNOPSIS... HIGH PRESSURE REMAINS ANCHORED OFF THE CAROLINA COAST TODAY...BEFORE DRIFTING SOUTHEAST MONDAY AS LOW PRESSURE LIFTS THROUGH THE NORTHEAST STATES. THE ASSOCIATED FRONTAL BOUNDARY DROPS THROUGH THE MID ATLANTIC MONDAY AND DISSIPATES OVER THE CAROLINAS TUESDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... LATEST IR/WV SAT IMAGERY SHOWING AN UPPER LOW OVER IN/IL AT 15Z THIS MORNING. A MOIST FRONTAL PLUME WAS NOTED FLOWING NORTHWARD AHEAD OF THE LOW FROM THE EASTERN GULF COAST TO THE EASTERN GREAT LAKES. MEANWHILE...SUBTROPICAL HIGH PRESSURE (SFC AND ALOFT) REMAINS ANCHORED OFF THE CAROLINA COAST. NO MAJOR CHANGES NECESSARY TO THE GOING FORECAST ATTM. THE UPPER SYSTEM IS WILL CONTINUE TO SLOWLY LIFT TOWARD THE EASTERN GREAT LAKES TODAY...WITH THE FRONTAL BAND SLOWLY MOVING EASTWARD OVER THE APPALACHIANS. THERE IS A LACK OF SYNOPTIC SCALE FORCING TODAY TO TRIGGER CONVECTION LOCALLY DESPITE A RATHER UNSTABLE ENVIRONMENT. HRRR CONTINUES TO PICK UP ON THIS TREND WELL, YIELDING ONLY AN ISOLATED TSRA OR TWO AT MOST THROUGH 22Z/6PM. ACCORDINGLY...HAVE PUSHED BACK POPS WITH SLOWER ONSET THROUGH THIS TIME FRAME, ORIENTING ISO T WORDING ALONG AND WEST OF HIGHWAY 15 IN THE FAR NW PIEDMONT COUNTIES. THERE IS VERY LITTLE CHANGE IN THE LOW-LEVEL THERMAL PROFILE, AND THUS HV STUCK CLOSE TO A PERSISTENCE FORECAST FOR TODAY`S MAXIMA. LOOK FOR HIGHS RISING INTO THE UPPER 80S IMMEDIATE COAST...TO LOW 90S INLAND. DEWPOINTS SHOULD MIX DOWN INTO THE UPPER 60S DURING PEAK HEATING...HENCE RESULTANT HEAT INDICES SHOULD ONLY BE A FEW DEGREES HIGHER THAN THE AMBIENT TEMPERATURE. SKY COVER CHARACTERIZED AS PARTLY SUNNY WEST TO MOSTLY SUNNY EAST FOR THE BALANCE OF THE DAY. && .SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/... THE UPPER LOW LIFTS ACROSS THE NORTHEAST AND DAMPENS TONIGHT AND MONDAY...WITH THE FRONTAL BAND DROPPING INTO THE MID ATLANTIC. LATEST NUMERICAL GUIDANCE BRINGS THE MOISTURE PLUME INTO THE REGION MONDAY MORNING AND SLOWLY DROPS IT SE INTO SE VA AND NE NC BY THE AFTERNOON. THE EARLIER TIMING (EARLIER ARRIVAL OF MID-CLOUDS) ALONG WITH MOIST ADIABATIC MID-LEVEL LAPSE RATES HAMPERS POTENTIAL INSTABILITY...WHICH WOULD LIMIT CONVECTIVE COVERAGE MONDAY AFTERNOON. ADDITIONALLY...THE MID/UPPER LEVEL FLOW BECOMES MORE ZONAL...WHICH WOULD FURTHER LIMIT COVERAGE. GIVEN THIS...HAVE LOWERED POPS TO LOW-END CHANCE. 0-6KM BULK SHEAR VALUES ARE STILL PROGGED TO REACH 25-30KT...SO THERE IS A POSSIBILITY OF ISOLATED STRONGER THUNDERSTORMS IF A FEW POCKETS OF HIGHER INSTABILITY DO DEVELOP. THE MAIN THREAT WOULD BE BRIEF HEAVY RAIN AND STRONG WIND GUSTS. THE BOUNDARY WASHES OUT TUESDAY AS ZONAL PREVAILS ACROSS THE REGION. GFS/NAM EACH INDICATE AROUND 1500-1800 J/KG OF MLCAPE TUESDAY AFTERNOON. HOWEVER...DEEP LAYER SHEAR WILL BE MUCH LESS ALONG WITH LITTLE SYNOPTIC SCALE FORCING. THE HIGHER TERRAIN TO THE WEST WILL LIKELY BE THE TRIGGER FOR ANY THUNDERSTORMS...SOME OF WHICH COULD DRIFT EAST INTO THE PIEDMONT...SO CHANCE POPS WILL BE MAINTAINED THERE WITH SLIGHT CHANCE FARTHER EAST. SEASONABLY HOT (ALTHOUGH NOT EXCESSIVE) AND HUMID CONDITIONS WILL CONTINUE MONDAY AND TUESDAY. HIGHS SHOULD RANGE FROM THE UPPER 80S TO LOW 90S...ALONG WITH LOWS IN THE LOW/MID 70S. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... LONG TERM PERIOD STARTS OFF TUE NGT INTO WED WITH ZONAL FLOW ALOFT OVER THE MID ATLANTIC AND AN UPR-LVL LO STARTING TO DIG OVER THE GREAT LAKES REGION. ALTHO BEST FORCING AND MOISTURE WILL STAY NW OF THE LOCAL AREA WED...DID INCLUDE A 20-30% CHC FOR SHRAS/TSTMS DUE TO DIURNALLY-DRIVEN CONVECTION IN THE WARM SECTOR. BETTER CHC FOR RAIN (40-50%) COMES LATE THU AS THE UPR-LVL TROF AND ASSOCIATED COLD FRONT APPROACH FROM THE OH VALLEY AND DEEP-LAYER MOISTURE INCREASES. THE FRONT WILL SLOW DOWN/STALL OVER THE AREA FRI (AND ALSO SAT?) LEADING TO CONTINUED CHCS FOR SHRAS/TSTMS. SLY FLOW AND ABUNDANT LO-LVL MOISTURE WILL CONTINUE TO PRODUCE HUMID CONDS (DEWPTS AVG IN THE LWR 70S) WITH HI TEMPS IN THE UPR 80S/LWR 90S AND LO TEMPS AVG IN THE LWR 70S. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... SOME CU AROUND THIS AFTERNOON WITH VFR CIGS NOW AT ALL TAF SITES. LOOKING AT THE MODEL SOUNDINGS THE CU WILL DISSIPATE AFTER SUNSET WITH MAINLY SOME CI LEFT. HOWEVER OUT TOWARD RIC COULD HAVE MORE CLOUDS AS AN UPPER SYSTEM STARTS MOVING TO THE NW OF RIC. THIS COULD EVEN BRING A SHOWER INTO RIC AFTER MIDNIGHT. KEEPING VFR CONDITIONS TONIGHT AS BELIEVE ENOUGH WINDS WILL OCCUR TO KEEP MIXING UP. THE UPPER TROF PUSHES ACROSS TO THE N OF THE AREA ON MON. THIS COULD PRODUCE SCATTERED SHOWERS OR TSTMS DURING THE DAY ON MONDAY. MODELS INDICATE THE BEST CHANCES OVER SE VA TO NE NORTH CAROLINA BY AFTERNOON. OUTSIDE OF THE SHOWERS AND THUNDERSTORMS VFR CONDITIONS WILL PREVAIL ON MONDAY. OUTLOOK...SCATTERED TSTMS...MAINLY AFTN/EVE WILL BE POSSIBLE TUE AND WED. MORE WIDESPREAD PCPN IS POSSIBLE LATE IN THE WEEK. && .MARINE... GENERALLY BENIGN SUB-SCA CONDITIONS OVER THE MARINE AREA THRU AT LEAST THE MIDDLE OF THE COMING WEEK. BERMUDA HIGH PRESSURE WILL SLOWLY WEAKEN/DRIFT EASTWARD TODAY THRU TONIGHT AS A LOW PRESSURE SYSTEM APPROACHES FROM THE WEST. NO STRONG SFC FRONT WILL BE ASSOCIATED WITH THIS SYSTEM. WINDS THRU MIDWEEK WILL AVG 10-15 KT OUT OF THE S/SW. EXPECT 1-2 FT WAVES OVER THE BAY AND 2-3 FT SEAS OVER COASTAL WATERS...APPROACHING 4 FT OUT 20 NM ON MON AND AGAIN WED. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...NONE. && $$ SYNOPSIS...AJZ NEAR TERM...AJZ/MAM SHORT TERM...AJZ LONG TERM...MAS AVIATION...JDM/JAB MARINE...JDM
AREA FORECAST DISCUSSION...CORRECTION
NWS WAKEFIELD VA
1130 AM EDT SUN JUL 7 2013 .SYNOPSIS... HIGH PRESSURE REMAINS ANCHORED OFF THE CAROLINA COAST TODAY...BEFORE DRIFTING SOUTHEAST MONDAY AS LOW PRESSURE LIFTS THROUGH THE NORTHEAST STATES. THE ASSOCIATED FRONTAL BOUNDARY DROPS THROUGH THE MID ATLANTIC MONDAY AND DISSIPATES OVER THE CAROLINAS TUESDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... LATEST IR/WV SAT IMAGERY SHOWING AN UPPER LOW OVER IN/IL AT 15Z THIS MORNING. A MOIST FRONTAL PLUME WAS NOTED FLOWING NORTHWARD AHEAD OF THE LOW FROM THE EASTERN GULF COAST TO THE EASTERN GREAT LAKES. MEANWHILE...SUBTROPICAL HIGH PRESSURE (SFC AND ALOFT) REMAINS ANCHORED OFF THE CAROLINA COAST. NO MAJOR CHANGES NECESSARY TO THE GOING FORECAST ATTM. THE UPPER SYSTEM IS WILL CONTINUE TO SLOWLY LIFT TOWARD THE EASTERN GREAT LAKES TODAY...WITH THE FRONTAL BAND SLOWLY MOVING EASTWARD OVER THE APPALACHIANS. THERE IS A LACK OF SYNOPTIC SCALE FORCING TODAY TO TRIGGER CONVECTION LOCALLY DESPITE A RATHER UNSTABLE ENVIRONMENT. HRRR CONTINUES TO PICK UP ON THIS TREND WELL, YIELDING ONLY AN ISOLATED TSRA OR TWO AT MOST THROUGH 22Z/6PM. ACCORDINGLY...HAVE PUSHED BACK POPS WITH SLOWER ONSET THROUGH THIS TIME FRAME, ORIENTING ISO T WORDING ALONG AND WEST OF HIGHWAY 15 IN THE FAR NW PIEDMONT COUNTIES. THERE IS VERY LITTLE CHANGE IN THE LOW-LEVEL THERMAL PROFILE, AND THUS HV STUCK CLOSE TO A PERSISTENCE FORECAST FOR TODAY`S MAXIMA. LOOK FOR HIGHS RISING INTO THE UPPER 80S IMMEDIATE COAST...TO LOW 90S INLAND. DEWPOINTS SHOULD MIX DOWN INTO THE UPPER 60S DURING PEAK HEATING...HENCE RESULTANT HEAT INDICES SHOULD ONLY BE A FEW DEGREES HIGHER THAN THE AMBIENT TEMPERATURE. SKY COVER CHARACTERIZED AS PARTLY SUNNY WEST TO MOSTLY SUNNY EAST FOR THE BALANCE OF THE DAY. && .SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/... THE UPPER LOW LIFTS ACROSS THE NORTHEAST AND DAMPENS TONIGHT AND MONDAY...WITH THE FRONTAL BAND DROPPING INTO THE MID ATLANTIC. LATEST NUMERICAL GUIDANCE BRINGS THE MOISTURE PLUME INTO THE REGION MONDAY MORNING AND SLOWLY DROPS IT SE INTO SE VA AND NE NC BY THE AFTERNOON. THE EARLIER TIMING (EARLIER ARRIVAL OF MID-CLOUDS) ALONG WITH MOIST ADIABATIC MID-LEVEL LAPSE RATES HAMPERS POTENTIAL INSTABILITY...WHICH WOULD LIMIT CONVECTIVE COVERAGE MONDAY AFTERNOON. ADDITIONALLY...THE MID/UPPER LEVEL FLOW BECOMES MORE ZONAL...WHICH WOULD FURTHER LIMIT COVERAGE. GIVEN THIS...HAVE LOWERED POPS TO LOW-END CHANCE. 0-6KM BULK SHEAR VALUES ARE STILL PROGGED TO REACH 25-30KT...SO THERE IS A POSSIBILITY OF ISOLATED STRONGER THUNDERSTORMS IF A FEW POCKETS OF HIGHER INSTABILITY DO DEVELOP. THE MAIN THREAT WOULD BE BRIEF HEAVY RAIN AND STRONG WIND GUSTS. THE BOUNDARY WASHES OUT TUESDAY AS ZONAL PREVAILS ACROSS THE REGION. GFS/NAM EACH INDICATE AROUND 1500-1800 J/KG OF MLCAPE TUESDAY AFTERNOON. HOWEVER...DEEP LAYER SHEAR WILL BE MUCH LESS ALONG WITH LITTLE SYNOPTIC SCALE FORCING. THE HIGHER TERRAIN TO THE WEST WILL LIKELY BE THE TRIGGER FOR ANY THUNDERSTORMS...SOME OF WHICH COULD DRIFT EAST INTO THE PIEDMONT...SO CHANCE POPS WILL BE MAINTAINED THERE WITH SLIGHT CHANCE FARTHER EAST. SEASONABLY HOT (ALTHOUGH NOT EXCESSIVE) AND HUMID CONDITIONS WILL CONTINUE MONDAY AND TUESDAY. HIGHS SHOULD RANGE FROM THE UPPER 80S TO LOW 90S...ALONG WITH LOWS IN THE LOW/MID 70S. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... LONG TERM PERIOD STARTS OFF TUE NGT INTO WED WITH ZONAL FLOW ALOFT OVER THE MID ATLANTIC AND AN UPR-LVL LO STARTING TO DIG OVER THE GREAT LAKES REGION. ALTHO BEST FORCING AND MOISTURE WILL STAY NW OF THE LOCAL AREA WED...DID INCLUDE A 20-30% CHC FOR SHRAS/TSTMS DUE TO DIURNALLY-DRIVEN CONVECTION IN THE WARM SECTOR. BETTER CHC FOR RAIN (40-50%) COMES LATE THU AS THE UPR-LVL TROF AND ASSOCIATED COLD FRONT APPROACH FROM THE OH VALLEY AND DEEP-LAYER MOISTURE INCREASES. THE FRONT WILL SLOW DOWN/STALL OVER THE AREA FRI (AND ALSO SAT?) LEADING TO CONTINUED CHCS FOR SHRAS/TSTMS. SLY FLOW AND ABUNDANT LO-LVL MOISTURE WILL CONTINUE TO PRODUCE HUMID CONDS (DEWPTS AVG IN THE LWR 70S) WITH HI TEMPS IN THE UPR 80S/LWR 90S AND LO TEMPS AVG IN THE LWR 70S. && .AVIATION /15Z SUNDAY THROUGH THURSDAY/... VFR CONDITIONS AND RELATIVELY LIGHT WINDS ARE EXPECTED THROUGH THE TAF PERIOD. ISOLD AFTN TSMS ARE POSSIBLE THIS AFTERNOON...MAINLY WEST OF KRIC. OUTLOOK...SCATTERED TSTMS...MAINLY AFTN/EVE WILL BE POSSIBLE MON- WED. MORE WIDESPREAD PCPN IS POSSIBLE LATE IN THE WEEK. && .MARINE... GENERALLY BENIGN SUB-SCA CONDITIONS OVER THE MARINE AREA THRU AT LEAST THE MIDDLE OF THE COMING WEEK. BERMUDA HIGH PRESSURE WILL SLOWLY WEAKEN/DRIFT EASTWARD TODAY THRU TONIGHT AS A LOW PRESSURE SYSTEM APPROACHES FROM THE WEST. NO STRONG SFC FRONT WILL BE ASSOCIATED WITH THIS SYSTEM. WINDS THRU MIDWEEK WILL AVG 10-15 KT OUT OF THE S/SW. EXPECT 1-2 FT WAVES OVER THE BAY AND 2-3 FT SEAS OVER COASTAL WATERS...APPROACHING 4 FT OUT 20 NM ON MON AND AGAIN WED. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...NONE. && $$ SYNOPSIS...AJZ NEAR TERM...AJZ/MAM SHORT TERM...AJZ LONG TERM...MAS AVIATION...JDM/DAP MARINE...JDM
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
139 PM EDT SUN JUL 7 2013 LATEST UPDATE... AVIATION .SYNOPSIS... ISSUED AT 314 AM EDT SUN JUL 7 2013 THE WEATHER PATTERN WILL CHANGE LITTLE OVER THE NEXT FEW DAYS. IT WILL REMAIN WARM AND HUMID WITH HIGHS IN THE MID TO UPPER 80S. WE WILL ALSO SEE SCATTERED SHOWERS AND STORMS. THE BEST CHANCE OF PRECIPITATION IN THE SHORT TERM WILL COME LATE TONIGHT INTO MONDAY MORNING...WITH ANOTHER GOOD CHANCE ON TUESDAY. THE SHOWERS AND STORMS SHOULD LINGER INTO WEDNESDAY...BUT THEN THE LATTER HALF OF THE WEEK LOOKS DRY. DAYTIME TEMPERATURES WILL LARGELY BE IN THE 80 TO 85 DEGREE RANGE FROM MID WEEK INTO NEXT WEEKEND. && .UPDATE... ISSUED AT 1048 AM EDT SUN JUL 7 2013 I UPDATED THE ZONE FORECAST TO INCREASE THE CHANCE FOR SHOWERS INTO EARLY THIS AFTERNOON OVER THE EASTERN SECTIONS OUR OUR CWA AND TO DECREASE THE FORECAST HIGH A TOUCH SINCE THERE IS A CONSIDERABLE AMOUNT OF MID CLOUD AROUND. THE 700 MB LOW IS NEARLY OVERHEAD OF GRAND RAPIDS AT 9 AM BASED ON RADAR DATA SHOWING THE SHOWERS PINWHEELING AROUND GRAND RAPIDS. THIS IS ALSO SUPPORTED BY BOTH VISIBLE SATELLITE LOOPS AND RAP MODEL 12Z FORECAST. THAT SUPPORTS THE SHOWERS OVER THE INFLOW SECTION OF THE LOW...EAST OF GRR ACTUALLY WITH A DEFORMATION ZONE FEATURE FROM NORTHERN KENT COUNTY INTO GRATIOT COUNTY. NOT MUCH THUNDER HAPPENING THOUGH. WHILE THAT WAS HAPPENING THERE IS AN MCS OVER THE WESTERN UPPER PENINSULA OF MICHIGAN THAT SEEMS TO BE WEAKENING AND BUILDING TOWARD THE SOUTHEAST. WITH THE 700 MB LOW WEAKENING AND MOVING INTO EASTERN LOWER MICHIGAN THIS AFTERNOON THAT WOULD PUT WESTERN LOWER MICHIGAN IN NORTHWEST SUBSIDING FLOW ON THE WEST SIDE OF THE LOW. NOT A GOOD THING IF ONE WANTS SHOWERS. SO MY SPIN IS THE CLOUDS AND SHOWERS WILL GRADUALLY MOVE EAST OF SOUTHWEST LOWER MICHIGAN DURING THE AFTERNOON. WITH THE SUBSIDENCE ON THE WEST SIDE OF THE SYSTEM I DO NOT SEE MUCH THREAT FOR CONVECTION TO DEVELOP SO I HAVE VERY LOW POPS WEST OF US-131 AFTER 1 PM (WEST WINDS OFF LAKE MICHIGAN DO NOT HELP THE CAUSE FOR CONVECTION MUCH EITHER).THIS IS STRONGLY SUPPORTED BY RAP MODEL SOUNDING WITH SHOW A VERY DRY LOOKING SOUNDING FROM THE SURFACE THROUGH 300 MB BY 21Z NEAR GRR. IT IS MORE MOIST ON THE RAP SOUNDING IN THE LAN/JXN AREA THIS AFTERNOON WITH NEAR 1800 J/KG OF CAPE BUT I WITH GENERIC WEST WINDS THROUGH 700 MB BY 21Z I SEE LITTLE REASON FOR MUCH SURFACE CONVERGENCE SO I AM STILL NOT TO EXITED ABOUT STORM POTENTIAL EVEN THERE. WE WILL HAVE TO WATCH WHAT HAPPENS WITH THE MCS OVER THE WESTERN UPPER PENINSULA FOR THIS EVENING BUT EVEN THERE... THE LOW LEVEL JET IS LARGELY IN WISCONSIN THIS EVENING AND THE BEST JET DYNAMICS ARE OVER NORTHERN WI AND THE MICHIGAN UP SO I BELIEVE LITTLE WILL HAPPEN OVER WESTERN LOWER MICHIGAN TONIGHT EITHER. && .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 314 AM EDT SUN JUL 7 2013 WIDELY SCATTERED SHOWERS AND STORMS WILL CONTINUE THROUGH THE SHORT TERM. HOWEVER THE PRECIPITATION SHOULD BECOME MORE WIDESPREAD LATE TONIGHT INTO MONDAY MORNING...AND THEN AGAIN ON TUESDAY. IT WILL REMAIN WARM AND HUMID THROUGH TUESDAY. AN UPPER LOW WAS OVER SE IL THIS MORNING AND IT WAS DRIFTING NE. THIS WILL BRING THE CENTER OF THE LOW TO NE INDIANA BY THIS AFTERNOON. THIS IS FURTHER NORTH THAN WHAT PREVIOUS MODELS HAVE BEEN SHOWING. FOR THE PAST FEW DAYS THERE HAS BEEN DAYTIME THUNDERSTORMS NEAR AND AROUND THIS LOW. HOWEVER THE COVERAGE OF THE PCPN STILL WARRANTS 30/40 POPS. ALSO BY THE END OF THE DAY A COLD FRONT WILL BE MOVING ACROSS WI. THIS COULD BRING ISOLATED PCPN INTO THE NW CWA AND 20/30 POPS WILL BE CARRIED OVER THE NW CWA. DECENT SET UP FOR AN MCS TO ROLL ALONG THE FRONT TO OUR WEST TONIGHT WITH THE ASSISTANCE OF A LOW LEVEL JET. SEEMS LIKE THIS MAY TRACK NEAR THE MI/IN BORDER LATE TONIGHT IN A WEAKENING STATE. ITS DOUBTFUL THAT SEVERE WILL OCCUR AS THIS COMPLEX WILL BE RUNNING AWAY FROM THE BEST INSTABILITY AND JET SUPPORT BY THE TIME IT REACHES US...BUT WILL CARRY 40/50 POPS SOUTH OF I-96. EXPECT SOMEWHAT LESS CONVECTION INTO MONDAY AFTERNOON AND MONDAY NIGHT. THE FRONT EASES INTO THE REGION...BUT IT WASHES OUT OVER THE NORTHERN OR CENTRAL CWA. THIS MAY SUPPORT SOME WIDELY SCATTERED STORMS BUT WITHOUT A FOCUSED JET THESE SHOULD NOT BE SEVERE. ANOTHER UP TICK IN THE STORM ACTIVITY IS EXPECTED INTO TUESDAY. ANOTHER COLD FRONT WILL BE CROSSING WI WITH A STRONG LOW LEVEL JET ALONG IT. THE CONVERGENCE FROM THIS JET SHOULD REACH US BY LATE AFTERNOON WHEN THE CHANCE OF ORGANIZED/SEVERE STORMS WILL BE POSSIBLE. HAVE INCREASED POPS TO LIKELY SOUTH OF I-96 AS THIS IS WHERE THE LLJ IS PROGGED TO BE NOSING INTO. .LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY) ISSUED AT 335 AM EDT SUN JUL 7 2013 BEST CHANCE OF RAIN IN THE EXTENDED WILL BE TUESDAY NIGHT INTO EARLY WEDNESDAY AS UPPER TROUGH AXIS AND SFC LOW MOVES THROUGH. PLENTY OF MOISTURE AVAILABLE AND MCS DEVELOPMENT IS POSSIBLE TUESDAY NIGHT INTO WEDNESDAY MORNING WITH HEAVY RAIN THREAT. MODELS HAVE TRENDED TO A LESS AMPLIFIED TROUGH AND WEAKER SHEAR PROFILES SO SEVERE THREAT NOW SEEMS TO BE DIMINISHED. KEPT THE LATTER PART OF THE WEEK DRY AS SFC HIGH IS IN PLACE AND DRY SOUNDINGS RULE FROM LATE WEDNESDAY THROUGH THE END OF THE PERIOD. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 138 PM EDT SUN JUL 7 2013 CONDITIONS SHOULD BE VFR FOR THE MAJORITY OF THE TIME THROUGH 18Z MON...WITH SOME MVFR POSSIBLE IN FOG TONIGHT AND ISOLATED SHOWERS. LOWER CLOUD COVER IN PLACE EARLIER THIS MORNING HAS BROKEN UP/LIFTED INTO A VFR DECK THIS AFTERNOON. SOME SCATTERED CLOUDS AROUND 2000-3000 FT STILL COULD BRIEFLY GO MVFR...BUT CONDITIONS WILL GENERALLY IMPROVE THROUGH THE AFTERNOON. THERE COULD BE A SHOWER ACROSS THE ERN TERMINALS OF KLAN AND KJXN DUE TO THE UPPER LOW CLOSER BY...SO VCSH WAS PUT IN THE FCST THERE UNTIL ABOUT 23Z. WE CAN NOT RULE OUT A FEW SHOWERS APPROACHING FROM THE W/NW LATE TODAY FROM CONVECTION THAT MIGHT DEVELOP ACROSS WISCONSIN THIS AFTERNOON. CONFIDENCE IS TOO LOW AT THIS TIME TO PUT ANYTHING IN THE FCST FOR THIS. WINDS WILL DIMINISH A BIT AROUND SUNSET AND REMAIN AROUND 3-5 KNOTS OVERNIGHT. THE MOIST/HUMID AIR MASS WILL ALLOW FOR SOME LIGHT FOG TO BE POSSIBLE ONCE AGAIN TOWARD DAYBREAK MON. A WEAK WAVE WILL MOVE INTO THE AREA DURING THE DAY ON MON THIS WILL PRODUCE ANOTHER THREAT OF A FEW SHOWERS. WE HAVE THESE IN THE FCST BEGINNING AROUND 14Z AND LASTING THROUGH 18Z. && .MARINE... ISSUED AT 314 AM EDT SUN JUL 7 2013 SOUTHERLY WINDS ARE EXPECTED TO INCREASE TONIGHT AHEAD OF AN APPROACHING COLD FRONT. AREAS NORTH OF HOLLAND WILL SEE WAVES INCREASE TO 2-3 FEET. THIS IS BELOW SMALL CRAFT CRITERIA...BUT THE LAKE WILL STILL BECOME RATHER ROUGH. WINDS AND WAVES ARE EXPECTED TO RELAX INTO MONDAY AS THE FRONT MOVES IN. && .HYDROLOGY... ISSUED AT 314 AM EDT SUN JUL 7 2013 THE WIDELY SCATTERED SHOWERS SHOULD RESULT WITH MOST RIVER BASIN SEEING AN AVERAGE OF AROUND A QUARTER INCH OF RAIN THROUGH MONDAY NIGHT...PERHAPS A BIT HIGHER SOUTH OF I-96. A BETTER CHANCE FOR WIDESPREAD RAINS COMES IN ON TUESDAY. EXPECT AREAS INLAND FROM THE LAKE AND SOUTH OF HIGHWAY 20 WILL STAND THE BEST CHANCE OF SEEING A HALF INCH OR MORE OF RAIN. LOCALIZED HEAVIER RAINS MAY OCCUR AND PRODUCE NUISANCE FLOODING...BUT IN GENERAL NO HYDRO ISSUES ARE EXPECTED. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. && $$ UPDATE...WDM SYNOPSIS...JK SHORT TERM...JK LONG TERM...OSTUNO AVIATION...NJJ HYDROLOGY...JK MARINE...JK
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
130 PM EDT SUN JUL 7 2013 .UPDATE... ISSUED AT 1030 AM EDT SUN JUL 7 2013 REMNANTS OF OVERNIGHT MCS CONTINUE TO MOVE IN THE EASTERN U.P. THIS MORNING AS THEY CONTINUE TO DIMINISH. TRAINING STORMS EARLIER THIS MORNING DUMPED BETWEEN 2 AND 4 INCHES OF RAIN ACROSS GOGEBIC AND ONTONAGON COUNTIES BUT AMOUNTS HAVE BEEN MUCH LIGHT FARTHER EAST. EXPECT A BREAK IN PRECIPITATION INTO THE AFTERNOON HOURS. HIRES MODELS CONTINUE TO SHOW SCATTERED REDEVELOPMENT OCCURRING ALONG THE SURFACE TROUGH THIS AFTERNOON AS IT SAGS SOUTHWARD. STILL SOME UNCERTAINTY THERE AND WILL HAVE TO MONITOR THROUGH THE AFTERNOON HOURS. WILL ADJUST POP FORECAST ACCORDINGLY WITH THAT THOUGHT PROCESS IN MIND. WITH MORE CLOUDS TODAY...TEMPS SHOULD ONLY CLIMB INTO THE UPPER 70S TO AROUND 80. .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 505 AM EDT SUN JUL 7 2013 WV IMAGERY AND RUC ANALYSIS INDICATED A MAINLY ZONAL PATTERN ACROSS THE NRN CONUS AND SRN CANADA WITH A CUTOFF MID/UPPER LEVEL LOW TO THE SOUTH OVER IL/IN. A SHORTWAVE TROUGH COMBINED WITH UPPER LEVEL DIV WITH THE RIGHT ENTRANCE OF A 75 KNOT 250 JET OVER NRN ONTARIO...AND FAVORABLE 925-700 THETA/E ADVECTION FROM THE UPPER MS VALLEY SUPPORTED AN AREA OF SHRA/TSRA OVER LAKE SUPERIOR INTO W UPPER MI AND NW WI WITH THE STRONGEST CONVECTION ON THE WRN END OF THE PCPN AREA. AT THE SFC...A COLD FRONT HAD GRADUALLY SAGGED TO THE SOUTH INTO NRN UPPER MI. TODAY...EXPECT THAT WEAKENING SHRA/TSRA WILL CONTINUE TO SPREAD THROUGH WRN INTO N CNTRL UPPER MI EARLY...PER RADAR AND SHORT RANGE MODEL TRENDS...BEFORE THE FORCING ASSOCIATED WITH THE SHRTWV AND LOW LEVEL INFLOW WEAKENS. BY LATE MORNING INTO THE EARLY AFTERNOON...THERE MAY BE A LULL IN ANY PCPN BEFORE ADDITIONAL SCT SHRA/TSRA ALONG THE FRONTAL BOUNDARY REINFORCED BY LAKE SUPERIOR BREEZE. THERE MAY BE ENOUGH THINNING OR BREAKS IN THE CLOUD COVER FOR TEMPS TO RECOVER TO NEAR 80...PUSHING MLCAPE VALUES INTO THE 1000-1500 J/KG RANGE. HOWEVER...0-6KM SHEAR VALUES TO NEAR 30 KT WILL REMAIN MARGINAL FOR STRONGER OR SEVERE ORGANIZED CONVECTION. THERE MAY STILL BE BRIEF HEAVY RAIN AND GUSTY WINDS WITH TSRA THAT DEVELOP. TONIGHT...AS DAYTIME HEATING SUBSIDES AND THE FRONT CONTINUES TO PUSH TO THE SOUTH...THE REMAINING PCPN SHOULD SHIFT TO THE SOUTH AND EAST AND DIMINISH. WITH LINGERING LOW LEVEL MOISTURE AND MID LEVEL DRYING...AREAS OF FOG ARE EXPECTED TO DEVELOP. THERE COULD ALSO BE SOME DRIZZLE NEAR THE WRN SHORE AS WEAK LOW LEVEL CONV DEVELOPS WITH MOIST NE FLOW OFF THE LAKE. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 505 AM EDT SUN JUL 7 2013 THE SURFACE FRONT WILL BE SOUTH OF THE FORECAST AREA MONDAY MORNING...WITH WEAK SURFACE RIDGING ACROSS LAKE SUPERIOR. THIS WILL HELP TO OVERALL DRY THE ATMOSPHERE...HOWEVER IT WILL ALSO ALLOW FOR WEAK UPSLOPE FLOW IN AREAS NEAR LAKE SUPERIOR. THE NAM AND EVEN THE GFS SUGGEST A VERY SHALLOW SATURATED LAYER BELOW 1000 FT WHICH WOULD IMPLY AT LEAST A CHANCE FOR LOW CLOUDS AND DRIZZLE NEAR LAKE SUPERIOR MONDAY MORNING. HOWEVER...BY AFTERNOON ANY LOW CLOUD/DRIZZLE SHOULD MIX OUT. WILL ALSO MAINTAIN THE SLIGHT CHANCE POPS IN THE LAKE BREEZE AREAS OF WESTERN UPPER MICHIGAN AND NEAR LAKE MICHIGAN. ALTHOUGH THE NWP SUGGESTS A FAIRLY DRY ATMOSPHERE BEHIND THE FRONT AND BROAD SCALE SUBSIDENCE...THE 850MB FRONT WILL STALL OUT OVER THE AREA AND INTERIOR INSTABILITY RISES TO NEARLY 1500 J/KG. NOT TO CONFIDENT THAT ANY SHOWERS/STORMS WILL OCCUR MONDAY AFTERNOON...BUT ALSO NOT CONFIDENT ENOUGH TO REMOVE THE MENTION. REGARDLESS...MONDAY WILL BE COOLER AND A LITTLE LESS HUMID THAN TODAY WITH READINGS NEAR LAKE SUPERIOR DROPPING BACK INTO THE LOWER-MID 70S. MONDAY NIGHT SHOULD BE A FAIRLY QUIET NIGHT ACROSS THE AREA AS THE NEXT LOW PRESSURE SYSTEM DEVELOPS ACROSS THE PLAINS. THE MODELS HAVE BACKED OFF ANY PCPN FOR THE AREA MONDAY NIGHT...INSTEAD FOCUSING IT ACROSS MN WHERE THE BETTER LOW LEVEL MOISTURE TRANSPORT AND DEEP MOISTURE WILL BE LOCATED. SOME DISAGREEMENT REMAINS REGARDING TIMING OF PRECIPITATION ON TUESDAY. THERE IS A HINT FROM THE ECMWF AND GFS THAT AN MCS WILL BE ONGOING TO WEST OF THE AREA IN THE BROAD WARM ADVECTION/ISENTROPIC LIFT AREA IN SRN MN. THIS LEADS TO MUCH UNCERTAINTY REGARDING CONVECTIVE EVOLUTION TUE FOR THE AREA. THE MAIN FORCING MECHANISM TUE AND TUE NIGHT WILL CONTINUE TO BE THE NRN STREAM ENERGY DIVING OUT OF CANADA AND AMPLIFYING DURING THE DAY...AND HAVE OPTED TO FOCUS ON THIS FEATURE SIMILAR TO THE NAM SOLUTION. WITH THE BEST FORCING WITH ENERGY BEING LATE TUE AFTN AND EVENING...HAVE OPTED TO MAINTAIN THE HIGHEST POPS DURING THIS PERIOD. DEPENDING ON THE AMOUNT OF DEBRIS CLOUDS...MODEST INSTABILITY IS POSSIBLE ACROSS THE AREA TUE AFTN/EVENING HELPING TO MAINTAIN THUNDERSTORM DEVELOPMENT ALONG THE FRONT. CANNOT TOTALLY RULE OUT SOME ORGANIZATION TO THE STORMS LATER TUESDAY INTO TUESDAY EVENING AS A COUPLED UPPER JET STRUCTURE DEVELOPS ACROSS THE NRN LAKES IN RESPONSE TO THE WAVE BECOMING NEGATIVELY TILTED. THE FRONT MOVES THROUGH THE AREA BY WEDNESDAY MORNING. MAY BE SOME RESIDUAL WRAP AROUND MOISTURE ACROSS THE AREA IN THE MORNING...BUT OTHERWISE THE WEATHER SHOULD IMPROVE DURING THE DAY. MODELS IN EXCELLENT AGREEMENT IN SHOWING BROAD HIGH PRESSURE ACROSS THE UPPER GREAT LAKES FOR THE END OF THE WEEK WITH RISING HEIGHTS BY THE WEEKEND. TEMPERATURES WILL BE SEASONABLE THU AND FRIDAY ALTHOUGH ABOVE NORMAL TEMPS MAY RETURN BY SATURDAY WITH 850MB TEMPS PROGGED TO RISE TO +16 ACROSS THE WEST. CANNOT RULE OUT SHOWERS SATURDAY AFTERNOON AS BOTH THE GFS AND ECMWF HINT AS AN UPPER WAVE MOVING THROUGH THE AREA IN THE WESTERLY FLOW. HOWEVER...AT THIS TIME WILL OPT TO MAINTAIN A DRY FORECAST. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 130 PM EDT SUN JUL 7 2013 SURFACE TROUGH WILL DROP SLOWLY SOUTHWARD ACROSS UPPER MICHIGAN THIS AFTERNOON SHIFTING WINDS FROM THE SOUTHWEST TO THE NORTH. SCATTERED SHOWERS AND A FEW THUNDERSTORMS WILL DEVELOP ALONG THIS BOUNDARY AS IT MOVES SOUTHWARD BUT ANTICIPATED AREAL COVERAGE IS NOT ENOUGH TO INCLUDE A MENTION AT THE TAF SITES. LOW LEVEL MOISTURE WILL REMAIN AFTER THE TROUGH PASSES AND WITH SUBSTANTIAL MID LEVEL DRYING EXPECT FOG AND EVEN SOME DRIZZLE TO DEVELOP AT ALL THREE FORECAST LOCATIONS LOWERING CONDITIONS TO VLIFR NEAR AIRPORT MINIMUMS FOR THE OVERNIGHT AND EARLY MONDAY MORNING. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 505 AM EDT SUN JUL 7 2013 GIVEN EARLY SHIP OBSERVATIONS OF ZERO VISIBILITY OVER WESTERN LAKE SUPERIOR AND VERY HUMID AIRMASS OVER CHILLY WATER FOLLOWING SOME SHOWERS...A DENSE FOG ADVISORY WILL REMAIN IN EFFECT THIS MORNING FOR THE WEST HALF OF LAKE SUPERIOR. SOME DRYING ON SUNDAY AFTERNOON FOLLOWING A COLD FRONTAL PASSAGE SHOULD DISSIPATE THE THICKEST FOG. WINDS WILL REMAIN BELOW 15 KT ACROSS LAKE SUPERIOR THROUGH TUESDAY AS A WEAK SURFACE TROUGH DROPS SOUTHWARD ACROSS THE LAKE FOLLOWED BY AN AREA OF HIGH PRESSURE. WITH SHOWERS AND THUNDERSTORMS EARLY TODAY AND ADDITIONAL SCT SHRA/TSRA POSSIBLE THIS AFTERNOON...AREAS OF FOG WILL CONTINUE ACROSS THE LAKE. AS ANOTHER LOW DEVELOPS OVER THE PLAINS ON TUESDAY AND APPROACHES LAKE SUPERIOR ON WEDNESDAY....NORTHWESTERLY WINDS OF 15 TO 25 KNOTS WILL BE POSSIBLE BEHIND FOR A TIME WEDNESDAY AND WEDNESDAY NIGHT. A SURFACE HIGH MOVING OVER THE UPPER LAKES LATE IN THE WEEK WILL ALLOW LIGHT WINDS TO RETURN. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... DENSE FOG ADVISORY UNTIL 2 PM EDT /1 PM CDT/ THIS AFTERNOON FOR LSZ162-263-264. LAKE MICHIGAN... NONE. && $$ UPDATE...MZ SHORT TERM...JLB LONG TERM...MRD AVIATION...JLB MARINE...JLB
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1050 AM EDT SUN JUL 7 2013 LATEST UPDATE... UPDATE .SYNOPSIS... ISSUED AT 314 AM EDT SUN JUL 7 2013 THE WEATHER PATTERN WILL CHANGE LITTLE OVER THE NEXT FEW DAYS. IT WILL REMAIN WARM AND HUMID WITH HIGHS IN THE MID TO UPPER 80S. WE WILL ALSO SEE SCATTERED SHOWERS AND STORMS. THE BEST CHANCE OF PRECIPITATION IN THE SHORT TERM WILL COME LATE TONIGHT INTO MONDAY MORNING...WITH ANOTHER GOOD CHANCE ON TUESDAY. THE SHOWERS AND STORMS SHOULD LINGER INTO WEDNESDAY...BUT THEN THE LATTER HALF OF THE WEEK LOOKS DRY. DAYTIME TEMPERATURES WILL LARGELY BE IN THE 80 TO 85 DEGREE RANGE FROM MID WEEK INTO NEXT WEEKEND. && .UPDATE... ISSUED AT 1048 AM EDT SUN JUL 7 2013 I UPDATED THE ZONE FORECAST TO INCREASE THE CHANCE FOR SHOWERS INTO EARLY THIS AFTERNOON OVER THE EASTERN SECTIONS OUR OUR CWA AND TO DECREASE THE FORECAST HIGH A TOUCH SINCE THERE IS A CONSIDERABLE AMOUNT OF MID CLOUD AROUND. THE 700 MB LOW IS NEARLY OVERHEAD OF GRAND RAPIDS AT 9 AM BASED ON RADAR DATA SHOWING THE SHOWERS PINWHEELING AROUND GRAND RAPIDS. THIS IS ALSO SUPPORTED BY BOTH VISIBLE SATELLITE LOOPS AND RAP MODEL 12Z FORECAST. THAT SUPPORTS THE SHOWERS OVER THE INFLOW SECTION OF THE LOW...EAST OF GRR ACTUALLY WITH A DEFORMATION ZONE FEATURE FROM NORTHERN KENT COUNTY INTO GRATIOT COUNTY. NOT MUCH THUNDER HAPPENING THOUGH. WHILE THAT WAS HAPPENING THERE IS AN MCS OVER THE WESTERN UPPER PENINSULA OF MICHIGAN THAT SEEMS TO BE WEAKENING AND BUILDING TOWARD THE SOUTHEAST. WITH THE 700 MB LOW WEAKENING AND MOVING INTO EASTERN LOWER MICHIGAN THIS AFTERNOON THAT WOULD PUT WESTERN LOWER MICHIGAN IN NORTHWEST SUBSIDING FLOW ON THE WEST SIDE OF THE LOW. NOT A GOOD THING IF ONE WANTS SHOWERS. SO MY SPIN IS THE CLOUDS AND SHOWERS WILL GRADUALLY MOVE EAST OF SOUTHWEST LOWER MICHIGAN DURING THE AFTERNOON. WITH THE SUBSIDENCE ON THE WEST SIDE OF THE SYSTEM I DO NOT SEE MUCH THREAT FOR CONVECTION TO DEVELOP SO I HAVE VERY LOW POPS WEST OF US-131 AFTER 1 PM (WEST WINDS OFF LAKE MICHIGAN DO NOT HELP THE CAUSE FOR CONVECTION MUCH EITHER).THIS IS STRONGLY SUPPORTED BY RAP MODEL SOUNDING WITH SHOW A VERY DRY LOOKING SOUNDING FROM THE SURFACE THROUGH 300 MB BY 21Z NEAR GRR. IT IS MORE MOIST ON THE RAP SOUNDING IN THE LAN/JXN AREA THIS AFTERNOON WITH NEAR 1800 J/KG OF CAPE BUT I WITH GENERIC WEST WINDS THROUGH 700 MB BY 21Z I SEE LITTLE REASON FOR MUCH SURFACE CONVERGENCE SO I AM STILL NOT TO EXITED ABOUT STORM POTENTL EVEN THERE. WE WILL HAVE TO WATCH WHAT HAPPENS WITH THE MCS OVER THE WESTERN UPPER PENINSULA FOR THIS EVENING BUT EVEN THERE... THE LOW LEVEL JET IS LARGELY IN WISCONSIN THIS EVENING AND THE BEST JET DYNAMICS ARE OVER NORTHERN WI AND THE MICHIGAN UP SO I BELIEVE LITTLE WILL HAPPEN OVER WESTERN LOWER MICHIGAN TONIGHT EITHER. && .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 314 AM EDT SUN JUL 7 2013 WIDELY SCATTERED SHOWERS AND STORMS WILL CONTINUE THROUGH THE SHORT TERM. HOWEVER THE PRECIPITATION SHOULD BECOME MORE WIDESPREAD LATE TONIGHT INTO MONDAY MORNING...AND THEN AGAIN ON TUESDAY. IT WILL REMAIN WARM AND HUMID THROUGH TUESDAY. AN UPPER LOW WAS OVER SE IL THIS MORNING AND IT WAS DRIFTING NE. THIS WILL BRING THE CENTER OF THE LOW TO NE INDIANA BY THIS AFTERNOON. THIS IS FURTHER NORTH THAN WHAT PREVIOUS MODELS HAVE BEEN SHOWING. FOR THE PAST FEW DAYS THERE HAS BEEN DAYTIME THUNDERSTORMS NEAR AND AROUND THIS LOW. HOWEVER THE COVERAGE OF THE PCPN STILL WARRANTS 30/40 POPS. ALSO BY THE END OF THE DAY A COLD FRONT WILL BE MOVING ACROSS WI. THIS COULD BRING ISOLATED PCPN INTO THE NW CWA AND 20/30 POPS WILL BE CARRIED OVER THE NW CWA. DECENT SET UP FOR AN MCS TO ROLL ALONG THE FRONT TO OUR WEST TONIGHT WITH THE ASSISTANCE OF A LOW LEVEL JET. SEEMS LIKE THIS MAY TRACK NEAR THE MI/IN BORDER LATE TONIGHT IN A WEAKENING STATE. ITS DOUBTFUL THAT SEVERE WILL OCCUR AS THIS COMPLEX WILL BE RUNNING AWAY FROM THE BEST INSTABILITY AND JET SUPPORT BY THE TIME IT REACHES US...BUT WILL CARRY 40/50 POPS SOUTH OF I-96. EXPECT SOMEWHAT LESS CONVECTION INTO MONDAY AFTERNOON AND MONDAY NIGHT. THE FRONT EASES INTO THE REGION...BUT IT WASHES OUT OVER THE NORTHERN OR CENTRAL CWA. THIS MAY SUPPORT SOME WIDELY SCATTERED STORMS BUT WITHOUT A FOCUSED JET THESE SHOULD NOT BE SEVERE. ANOTHER UP TICK IN THE STORM ACTIVITY IS EXPECTED INTO TUESDAY. ANOTHER COLD FRONT WILL BE CROSSING WI WITH A STRONG LOW LEVEL JET ALONG IT. THE CONVERGENCE FROM THIS JET SHOULD REACH US BY LATE AFTERNOON WHEN THE CHANCE OF ORGANIZED/SEVERE STORMS WILL BE POSSIBLE. HAVE INCREASED POPS TO LIKELY SOUTH OF I-96 AS THIS IS WHERE THE LLJ IS PROGGED TO BE NOSING INTO. .LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY) ISSUED AT 335 AM EDT SUN JUL 7 2013 BEST CHANCE OF RAIN IN THE EXTENDED WILL BE TUESDAY NIGHT INTO EARLY WEDNESDAY AS UPPER TROUGH AXIS AND SFC LOW MOVES THROUGH. PLENTY OF MOISTURE AVAILABLE AND MCS DEVELOPMENT IS POSSIBLE TUESDAY NIGHT INTO WEDNESDAY MORNING WITH HEAVY RAIN THREAT. MODELS HAVE TRENDED TO A LESS AMPLIFIED TROUGH AND WEAKER SHEAR PROFILES SO SEVERE THREAT NOW SEEMS TO BE DIMINISHED. KEPT THE LATTER PART OF THE WEEK DRY AS SFC HIGH IS IN PLACE AND DRY SOUNDINGS RULE FROM LATE WEDNESDAY THROUGH THE END OF THE PERIOD. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 745 AM EDT SUN JUL 7 2013 SOME AREAS OF MVFR IN LIGHT FOG WITH ISOLATED IFR LOW STRATUS EARLY THIS MORNING WILL IMPROVE TO VFR BY 14Z. ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS EXPECTED THROUGH THE DAY. WINDS WILL BE SOUTHWEST AOB 10 KNOTS. && .MARINE... ISSUED AT 314 AM EDT SUN JUL 7 2013 SOUTHERLY WINDS ARE EXPECTED TO INCREASE TONIGHT AHEAD OF AN APPROACHING COLD FRONT. AREAS NORTH OF HOLLAND WILL SEE WAVES INCREASE TO 2-3 FEET. THIS IS BELOW SMALL CRAFT CRITERIA...BUT THE LAKE WILL STILL BECOME RATHER ROUGH. WINDS AND WAVES ARE EXPECTED TO RELAX INTO MONDAY AS THE FRONT MOVES IN. && .HYDROLOGY... ISSUED AT 314 AM EDT SUN JUL 7 2013 THE WIDELY SCATTERED SHOWERS SHOULD RESULT WITH MOST RIVER BASIN SEEING AN AVERAGE OF AROUND A QUARTER INCH OF RAIN THROUGH MONDAY NIGHT...PERHAPS A BIT HIGHER SOUTH OF I-96. A BETTER CHANCE FOR WIDESPREAD RAINS COMES IN ON TUESDAY. EXPECT AREAS INLAND FROM THE LAKE AND SOUTH OF HIGHWAY 20 WILL STAND THE BEST CHANCE OF SEEING A HALF INCH OR MORE OF RAIN. LOCALIZED HEAVIER RAINS MAY OCCUR AND PRODUCE NUISANCE FLOODING...BUT IN GENERAL NO HYDRO ISSUES ARE EXPECTED. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. && $$ UPDATE...WDM SYNOPSIS...JK SHORT TERM...JK LONG TERM...OSTUNO AVIATION...OSTUNO HYDROLOGY...JK MARINE...JK
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1030 AM EDT SUN JUL 7 2013 .UPDATE... ISSUED AT 1030 AM EDT SUN JUL 7 2013 REMNANTS OF OVERNIGHT MCS CONTINUE TO MOVE IN THE EASTERN U.P. THIS MORNING AS THEY CONTINUE TO DIMINISH. TRAINING STORMS EARLIER THIS MORNING DUMPED BETWEEN 2 AND 4 INCHES OF RAIN ACROSS GOGEBIC AND ONTONAGON COUNTIES BUT AMOUNTS HAVE BEEN MUCH LIGHT FARTHER EAST. EXPECT A BREAK IN PRECIPITATION INTO THE AFTERNOON HOURS. HIRES MODELS CONTINUE TO SHOW SCATTERED REDEVELOPMENT OCCURRING ALONG THE SURFACE TROUGH THIS AFTERNOON AS IT SAGS SOUTHWARD. STILL SOME UNCERTAINTY THERE AND WILL HAVE TO MONITOR THROUGH THE AFTERNOON HOURS. WILL ADJUST POP FORECAST ACCORDINGLY WITH THAT THOUGHT PROCESS IN MIND. WITH MORE CLOUDS TODAY...TEMPS SHOULD ONLY CLIMB INTO THE UPPER 70S TO AROUND 80. .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 505 AM EDT SUN JUL 7 2013 WV IMAGERY AND RUC ANALYSIS INDICATED A MAINLY ZONAL PATTERN ACROSS THE NRN CONUS AND SRN CANADA WITH A CUTOFF MID/UPPER LEVEL LOW TO THE SOUTH OVER IL/IN. A SHORTWAVE TROUGH COMBINED WITH UPPER LEVEL DIV WITH THE RIGHT ENTRANCE OF A 75 KNOT 250 JET OVER NRN ONTARIO...AND FAVORABLE 925-700 THETA/E ADVECTION FROM THE UPPER MS VALLEY SUPPORTED AN AREA OF SHRA/TSRA OVER LAKE SUPERIOR INTO W UPPER MI AND NW WI WITH THE STRONGEST CONVECTION ON THE WRN END OF THE PCPN AREA. AT THE SFC...A COLD FRONT HAD GRADUALLY SAGGED TO THE SOUTH INTO NRN UPPER MI. TODAY...EXPECT THAT WEAKENING SHRA/TSRA WILL CONTINUE TO SPREAD THROUGH WRN INTO N CNTRL UPPER MI EARLY...PER RADAR AND SHORT RANGE MODEL TRENDS...BEFORE THE FORCING ASSOCIATED WITH THE SHRTWV AND LOW LEVEL INFLOW WEAKENS. BY LATE MORNING INTO THE EARLY AFTERNOON...THERE MAY BE A LULL IN ANY PCPN BEFORE ADDITIONAL SCT SHRA/TSRA ALONG THE FRONTAL BOUNDARY REINFORCED BY LAKE SUPERIOR BREEZE. THERE MAY BE ENOUGH THINNING OR BREAKS IN THE CLOUD COVER FOR TEMPS TO RECOVER TO NEAR 80...PUSHING MLCAPE VALUES INTO THE 1000-1500 J/KG RANGE. HOWEVER...0-6KM SHEAR VALUES TO NEAR 30 KT WILL REMAIN MARGINAL FOR STRONGER OR SEVERE ORGANIZED CONVECTION. THERE MAY STILL BE BRIEF HEAVY RAIN AND GUSTY WINDS WITH TSRA THAT DEVELOP. TONIGHT...AS DAYTIME HEATING SUBSIDES AND THE FRONT CONTINUES TO PUSH TO THE SOUTH...THE REMAINING PCPN SHOULD SHIFT TO THE SOUTH AND EAST AND DIMINISH. WITH LINGERING LOW LEVEL MOISTURE AND MID LEVEL DRYING...AREAS OF FOG ARE EXPECTED TO DEVELOP. THERE COULD ALSO BE SOME DRIZZLE NEAR THE WRN SHORE AS WEAK LOW LEVEL CONV DEVELOPS WITH MOIST NE FLOW OFF THE LAKE. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 505 AM EDT SUN JUL 7 2013 THE SURFACE FRONT WILL BE SOUTH OF THE FORECAST AREA MONDAY MORNING...WITH WEAK SURFACE RIDGING ACROSS LAKE SUPERIOR. THIS WILL HELP TO OVERALL DRY THE ATMOSPHERE...HOWEVER IT WILL ALSO ALLOW FOR WEAK UPSLOPE FLOW IN AREAS NEAR LAKE SUPERIOR. THE NAM AND EVEN THE GFS SUGGEST A VERY SHALLOW SATURATED LAYER BELOW 1000 FT WHICH WOULD IMPLY AT LEAST A CHANCE FOR LOW CLOUDS AND DRIZZLE NEAR LAKE SUPERIOR MONDAY MORNING. HOWEVER...BY AFTERNOON ANY LOW CLOUD/DRIZZLE SHOULD MIX OUT. WILL ALSO MAINTAIN THE SLIGHT CHANCE POPS IN THE LAKE BREEZE AREAS OF WESTERN UPPER MICHIGAN AND NEAR LAKE MICHIGAN. ALTHOUGH THE NWP SUGGESTS A FAIRLY DRY ATMOSPHERE BEHIND THE FRONT AND BROAD SCALE SUBSIDENCE...THE 850MB FRONT WILL STALL OUT OVER THE AREA AND INTERIOR INSTABILITY RISES TO NEARLY 1500 J/KG. NOT TO CONFIDENT THAT ANY SHOWERS/STORMS WILL OCCUR MONDAY AFTERNOON...BUT ALSO NOT CONFIDENT ENOUGH TO REMOVE THE MENTION. REGARDLESS...MONDAY WILL BE COOLER AND A LITTLE LESS HUMID THAN TODAY WITH READINGS NEAR LAKE SUPERIOR DROPPING BACK INTO THE LOWER-MID 70S. MONDAY NIGHT SHOULD BE A FAIRLY QUIET NIGHT ACROSS THE AREA AS THE NEXT LOW PRESSURE SYSTEM DEVELOPS ACROSS THE PLAINS. THE MODELS HAVE BACKED OFF ANY PCPN FOR THE AREA MONDAY NIGHT...INSTEAD FOCUSING IT ACROSS MN WHERE THE BETTER LOW LEVEL MOISTURE TRANSPORT AND DEEP MOISTURE WILL BE LOCATED. SOME DISAGREEMENT REMAINS REGARDING TIMING OF PRECIPITATION ON TUESDAY. THERE IS A HINT FROM THE ECMWF AND GFS THAT AN MCS WILL BE ONGOING TO WEST OF THE AREA IN THE BROAD WARM ADVECTION/ISENTROPIC LIFT AREA IN SRN MN. THIS LEADS TO MUCH UNCERTAINTY REGARDING CONVECTIVE EVOLUTION TUE FOR THE AREA. THE MAIN FORCING MECHANISM TUE AND TUE NIGHT WILL CONTINUE TO BE THE NRN STREAM ENERGY DIVING OUT OF CANADA AND AMPLIFYING DURING THE DAY...AND HAVE OPTED TO FOCUS ON THIS FEATURE SIMILAR TO THE NAM SOLUTION. WITH THE BEST FORCING WITH ENERGY BEING LATE TUE AFTN AND EVENING...HAVE OPTED TO MAINTAIN THE HIGHEST POPS DURING THIS PERIOD. DEPENDING ON THE AMOUNT OF DEBRIS CLOUDS...MODEST INSTABILITY IS POSSIBLE ACROSS THE AREA TUE AFTN/EVENING HELPING TO MAINTAIN THUNDERSTORM DEVELOPMENT ALONG THE FRONT. CANNOT TOTALLY RULE OUT SOME ORGANIZATION TO THE STORMS LATER TUESDAY INTO TUESDAY EVENING AS A COUPLED UPPER JET STRUCTURE DEVELOPS ACROSS THE NRN LAKES IN RESPONSE TO THE WAVE BECOMING NEGATIVELY TILTED. THE FRONT MOVES THROUGH THE AREA BY WEDNESDAY MORNING. MAY BE SOME RESIDUAL WRAP AROUND MOISTURE ACROSS THE AREA IN THE MORNING...BUT OTHERWISE THE WEATHER SHOULD IMPROVE DURING THE DAY. MODELS IN EXCELLENT AGREEMENT IN SHOWING BROAD HIGH PRESSURE ACROSS THE UPPER GREAT LAKES FOR THE END OF THE WEEK WITH RISING HEIGHTS BY THE WEEKEND. TEMPERATURES WILL BE SEASONABLE THU AND FRIDAY ALTHOUGH ABOVE NORMAL TEMPS MAY RETURN BY SATURDAY WITH 850MB TEMPS PROGGED TO RISE TO +16 ACROSS THE WEST. CANNOT RULE OUT SHOWERS SATURDAY AFTERNOON AS BOTH THE GFS AND ECMWF HINT AS AN UPPER WAVE MOVING THROUGH THE AREA IN THE WESTERLY FLOW. HOWEVER...AT THIS TIME WILL OPT TO MAINTAIN A DRY FORECAST. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 747 AM EDT SUN JUL 7 2013 AN AREA OF SHRA/TSRA OVER WESTERN UPPER MI WILL DEPART FROM IWD AND CMX EARLY BUT WILL IMPACT SAW THROUGH MID MORNING WITH MAINLY MVFR CONDITIONS. DAYTIME HEATING AND MIXING WILL BRING IMPROVEMENT TO MAINLY VFR CONDITIONS BY THIS AFTERNOON. SCT SHRA/TSRA MAY REDEVELOP THIS AFTERNOON. CONFIDENCE IN COVERAGE/TIMING OF ANY TSTMS WAS LOW AND NOT INCLUDED AT THIS TIME. ABUNDANT LOW LEVEL MOISTURE WILL REMAIN IN PLACE TONIGHT AS THE MID LEVELS DRY ALLOWING FOG TO DEVELOP OVERNIGHT WHICH MAY DROP CONDITIONS TO VLIFR NEAR AIRPORT MINIMUMS. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 505 AM EDT SUN JUL 7 2013 GIVEN EARLY SHIP OBSERVATIONS OF ZERO VISIBILITY OVER WESTERN LAKE SUPERIOR AND VERY HUMID AIRMASS OVER CHILLY WATER FOLLOWING SOME SHOWERS...A DENSE FOG ADVISORY WILL REMAIN IN EFFECT THIS MORNING FOR THE WEST HALF OF LAKE SUPERIOR. SOME DRYING ON SUNDAY AFTERNOON FOLLOWING A COLD FRONTAL PASSAGE SHOULD DISSIPATE THE THICKEST FOG. WINDS WILL REMAIN BELOW 15 KT ACROSS LAKE SUPERIOR THROUGH TUESDAY AS A WEAK SURFACE TROUGH DROPS SOUTHWARD ACROSS THE LAKE FOLLOWED BY AN AREA OF HIGH PRESSURE. WITH SHOWERS AND THUNDERSTORMS EARLY TODAY AND ADDITIONAL SCT SHRA/TSRA POSSIBLE THIS AFTERNOON...AREAS OF FOG WILL CONTINUE ACROSS THE LAKE. AS ANOTHER LOW DEVELOPS OVER THE PLAINS ON TUESDAY AND APPROACHES LAKE SUPERIOR ON WEDNESDAY....NORTHWESTERLY WINDS OF 15 TO 25 KNOTS WILL BE POSSIBLE BEHIND FOR A TIME WEDNESDAY AND WEDNESDAY NIGHT. A SURFACE HIGH MOVING OVER THE UPPER LAKES LATE IN THE WEEK WILL ALLOW LIGHT WINDS TO RETURN. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... DENSE FOG ADVISORY UNTIL 2 PM EDT /1 PM CDT/ THIS AFTERNOON FOR LSZ162-263-264. LAKE MICHIGAN... NONE. && $$ UPDATE...MZ SHORT TERM...JLB LONG TERM...MRD AVIATION...JLB MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
748 AM EDT SUN JUL 7 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 505 AM EDT SUN JUL 7 2013 WV IMAGERY AND RUC ANALYSIS INDICATED A MAINLY ZONAL PATTERN ACROSS THE NRN CONUS AND SRN CANADA WITH A CUTOFF MID/UPPER LEVEL LOW TO THE SOUTH OVER IL/IN. A SHORTWAVE TROUGH COMBINED WITH UPPER LEVEL DIV WITH THE RIGH ENTRANCE OF A 75 KNOT 250 JET OVER NRN ONTARIO...AND FAVORABLE 925-700 THETA/E ADVECTION FROM THE UPPER MS VALLEY SUPPORTED AN AREA OF SHRA/TSRA OVER LAKE SUPERIOR INTO W UPPER MI AND NW WI WITH THE STRONGEST CONVECTION ON THE WRN END OF THE PCPN AREA. AT THE SFC...A COLD FRONT HAD GRADUALLY SAGGED TO THE SOUTH INTO NRN UPPER MI. TODAY...EXPECT THAT WEAKENING SHRA/TSRA WILL CONTINUE TO SPREAD THROUGH WRN INTO N CNTRL UPPER MI EARLY...PER RADAR AND SHORT RANGE MODEL TRENDS...BEFORE THE FORCING ASSOCIATED WITH THE SHRTWV AND LOW LEVEL INFLOW WEAKENS. BY LATE MORNING INTO THE EARLY AFTERNOON...THERE MAY BE A LULL IN ANY PCPN BEFORE ADDITIONAL SCT SHRA/TSRA ALONG THE FRONTAL BOUNDARY REINFORCED BY LAKE SUPERIOR BREEZE. THERE MAY BE ENOUGH THINNING OR BREAKS IN THE CLOUD COVER FOR TEMPS TO RECOVER TO NEAR 80...PUSHING MLCAPE VALUES INTO THE 1000-1500 J/KG RANGE. HOWEVER...0-6KM SHEAR VALUES TO NEAR 30 KT WILL REMAIN MARGINAL FOR STRONGER OR SEVERE ORGANIZED CONVECTION. THERE MAY STILL BE BRIEF HEAVY RAIN AND GUSTY WINDS WITH TSRA THAT DEVELOP. TONIGHT...AS DAYTIME HEATING SUBSIDES AND THE FRONT CONTINUES TO PUSH TO THE SOUTH...THE REMAINING PCPN SHOULD SHIFT TO THE SOUTH AND EAST AND DIMINISH. WITH LINGERING LOW LEVEL MOISTURE AND MID LEVEL DRYING...AREAS OF FOG ARE EXPECTED TO DEVELOP. THERE COULD ALSO BE SOME DRIZZLE NEAR THE WRN SHORE AS WEAK LOW LEVEL CONV DEVELOPS WITH MOIST NE FLOW OFF THE LAKE. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 505 AM EDT SUN JUL 7 2013 THE SURFACE FRONT WILL BE SOUTH OF THE FORECAST AREA MONDAY MORNING...WITH WEAK SURFACE RIDGING ACROSS LAKE SUPERIOR. THIS WILL HELP TO OVERALL DRY THE ATMOSPHERE...HOWEVER IT WILL ALSO ALLOW FOR WEAK UPSLOPE FLOW IN AREAS NEAR LAKE SUPERIOR. THE NAM AND EVEN THE GFS SUGGEST A VERY SHALLOW SATURATED LAYER BELOW 1000 FT WHICH WOULD IMPLY AT LEAST A CHANCE FOR LOW CLOUDS AND DRIZZLE NEAR LAKE SUPERIOR MONDAY MORNING. HOWEVER...BY AFTERNOON ANY LOW CLOUD/DRIZZLE SHOULD MIX OUT. WILL ALSO MAINTAIN THE SLIGHT CHANCE POPS IN THE LAKE BREEZE AREAS OF WESTERN UPPER MICHIGAN AND NEAR LAKE MICHIGAN. ALTHOUGH THE NWP SUGGESTS A FAIRLY DRY ATMOSPHERE BEHIND THE FRONT AND BROAD SCALE SUBSIDENCE...THE 850MB FRONT WILL STALL OUT OVER THE AREA AND INTERIOR INSTABILITY RISES TO NEARLY 1500 J/KG. NOT TO CONFIDENT THAT ANY SHOWERS/STORMS WILL OCCUR MONDAY AFTERNOON...BUT ALSO NOT CONFIDENT ENOUGH TO REMOVE THE MENTION. REGARDLESS...MONDAY WILL BE COOLER AND A LITTLE LESS HUMID THAN TODAY WITH READINGS NEAR LAKE SUPERIOR DROPPING BACK INTO THE LOWER-MID 70S. MONDAY NIGHT SHOULD BE A FAIRLY QUIET NIGHT ACROSS THE AREA AS THE NEXT LOW PRESSURE SYSTEM DEVELOPS ACROSS THE PLAINS. THE MODELS HAVE BACKED OFF ANY PCPN FOR THE AREA MONDAY NIGHT...INSTEAD FOCUSING IT ACROSS MN WHERE THE BETTER LOW LEVEL MOISTURE TRANSPORT AND DEEP MOISTURE WILL BE LOCATED. SOME DISAGREEMENT REMAINS REGARDING TIMING OF PRECIPITATION ON TUESDAY. THERE IS A HINT FROM THE ECMWF AND GFS THAT AN MCS WILL BE ONGOING TO WEST OF THE AREA IN THE BROAD WARM ADVECTION/ISENTROPIC LIFT AREA IN SRN MN. THIS LEADS TO MUCH UNCERTAINTY REGARDING CONVECTIVE EVOLUTION TUE FOR THE AREA. THE MAIN FORCING MECHANISM TUE AND TUE NIGHT WILL CONTINUE TO BE THE NRN STREAM ENERGY DIVING OUT OF CANADA AND AMPLIFYING DURING THE DAY...AND HAVE OPTED TO FOCUS ON THIS FEATURE SIMILAR TO THE NAM SOLUTION. WITH THE BEST FORCING WITH ENERGY BEING LATE TUE AFTN AND EVENING...HAVE OPTED TO MAINTAIN THE HIGHEST POPS DURING THIS PERIOD. DEPENDING ON THE AMOUNT OF DEBRIS CLOUDS...MODEST INSTABILITY IS POSSIBLE ACROSS THE AREA TUE AFTN/EVENING HELPING TO MAINTAIN THUNDERSTORM DEVELOPMENT ALONG THE FRONT. CANNOT TOTALLY RULE OUT SOME ORGANIZATION TO THE STORMS LATER TUESDAY INTO TUESDAY EVENING AS A COUPLED UPPER JET STRUCTURE DEVELOPS ACROSS THE NRN LAKES IN RESPONSE TO THE WAVE BECOMING NEGATIVELY TILTED. THE FRONT MOVES THROUGH THE AREA BY WEDNEDAY MORNING. MAY BE SOME RESIDUAL WRAP AROUND MOISTURE ACROSS THE AREA IN THE MORNING...BUT OTHERWISE THE WEATHER SHOULD IMPROVE DURING THE DAY. MODELS IN EXCELLENT AGREEMENT IN SHOWING BROAD HIGH PRESSURE ACROSS THE UPPER GREAT LAKES FOR THE END OF THE WEEK WITH RISING HEIGHTS BY THE WEEKEND. TEMPERATURES WILL BE SEASONABLE THU AND FRIDAY ALTHOUGH ABOVE NORMAL TEMPS MAY RETURN BY SATURDAY WITH 850MB TEMPS PROGGED TO RISE TO +16 ACROSS THE WEST. CANNOT RULE OUT SHOWERS SATURDAY AFTERNOON AS BOTH THE GFS AND ECMWF HINT AS AN UPPER WAVE MOVING THROUGH THE AREA IN THE WESTERLY FLOW. HOWEVER...AT THIS TIME WILL OPT TO MAINTAIN A DRY FORECAST. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 747 AM EDT SUN JUL 7 2013 AN AREA OF SHRA/TSRA OVER WESTERN UPPER MI WILL DEPART FROM IWD AND CMX EARLY BUT WILL IMPACT SAW THROUGH MID MORNING WITH MAINLY MVFR CONDITIONS. DAYTIME HEATING AND MIXING WILL BRING IMPROVEMENT TO MAINLY VFR CONDITIONS BY THIS AFTERNOON. SCT SHRA/TSRA MAY REDEVELOP THIS AFTERNOON. CONFIDENCE IN COVERAGE/TIMING OF ANY TSTMS WAS LOW AND NOT INCLUDED AT THIS TIME. ABUNDANT LOW LEVEL MOISTURE WILL REMAIN IN PLACE TONIGHT AS THE MID LEVELS DRY ALLOWING FOG TO DEVELOP OVERNIGHT WHICH MAY DROP CONDITIONS TO VLIFR NEAR AIRPORT MINIMUMS. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 505 AM EDT SUN JUL 7 2013 GIVEN EARLY SHIP OBSERVATIONS OF ZERO VISIBILITY OVER WESTERN LAKE SUPERIOR AND VERY HUMID AIRMASS OVER CHILLY WATER FOLLOWING SOME SHOWERS...A DENSE FOG ADVISORY WILL REMAIN IN EFFECT THIS MORNING FOR THE WEST HALF OF LAKE SUPERIOR. SOME DRYING ON SUNDAY AFTERNOON FOLLOWING A COLD FRONTAL PASSAGE SHOULD DISSIPATE THE THICKEST FOG. WINDS WILL REMAIN BELOW 15 KT ACROSS LAKE SUPERIOR THROUGH TUESDAY AS A WEAK SURFACE TROUGH DROPS SOUTHWARD ACROSS THE LAKE FOLLOWED BY AN AREA OF HIGH PRESSURE. WITH SHOWERS AND THUNDERSTORMS EARLY TODAY AND ADDITIONAL SCT SHRA/TSRA POSSIBLE THIS AFTERNOON...AREAS OF FOG WILL CONTINUE ACROSS THE LAKE. AS ANOTHER LOW DEVELOPS OVER THE PLAINS ON TUESDAY AND APPROACHES LAKE SUPERIOR ON WEDNESDAY....NORTHWESTERLY WINDS OF 15 TO 25 KNOTS WILL BE POSSIBLE BEHIND FOR A TIME WEDNESDAY AND WEDNESDAY NIGHT. A SURFACE HIGH MOVING OVER THE UPPER LAKES LATE IN THE WEEK WILL ALLOW LIGHT WINDS TO RETURN. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... DENSE FOG ADVISORY UNTIL 2 PM EDT /1 PM CDT/ THIS AFTERNOON FOR LSZ162-263-264. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...MRD AVIATION...JLB MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
507 AM EDT SUN JUL 7 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 505 AM EDT SUN JUL 7 2013 WV IMAGERY AND RUC ANALYSIS INDICATED A MAINLY ZONAL PATTERN ACROSS THE NRN CONUS AND SRN CANADA WITH A CUTOFF MID/UPPER LEVEL LOW TO THE SOUTH OVER IL/IN. A SHORTWAVE TROUGH COMBINED WITH UPPER LEVEL DIV WITH THE RIGH ENTRANCE OF A 75 KNOT 250 JET OVER NRN ONTARIO...AND FAVORABLE 925-700 THETA/E ADVECTION FROM THE UPPER MS VALLEY SUPPORTED AN AREA OF SHRA/TSRA OVER LAKE SUPERIOR INTO W UPPER MI AND NW WI WITH THE STRONGEST CONVECTION ON THE WRN END OF THE PCPN AREA. AT THE SFC...A COLD FRONT HAD GRADUALLY SAGGED TO THE SOUTH INTO NRN UPPER MI. TODAY...EXPECT THAT WEAKENING SHRA/TSRA WILL CONTINUE TO SPREAD THROUGH WRN INTO N CNTRL UPPER MI EARLY...PER RADAR AND SHORT RANGE MODEL TRENDS...BEFORE THE FORCING ASSOCIATED WITH THE SHRTWV AND LOW LEVEL INFLOW WEAKENS. BY LATE MORNING INTO THE EARLY AFTERNOON...THERE MAY BE A LULL IN ANY PCPN BEFORE ADDITIONAL SCT SHRA/TSRA ALONG THE FRONTAL BOUNDARY REINFORCED BY LAKE SUPERIOR BREEZE. THERE MAY BE ENOUGH THINNING OR BREAKS IN THE CLOUD COVER FOR TEMPS TO RECOVER TO NEAR 80...PUSHING MLCAPE VALUES INTO THE 1000-1500 J/KG RANGE. HOWEVER...0-6KM SHEAR VALUES TO NEAR 30 KT WILL REMAIN MARGINAL FOR STRONGER OR SEVERE ORGANIZED CONVECTION. THERE MAY STILL BE BRIEF HEAVY RAIN AND GUSTY WINDS WITH TSRA THAT DEVELOP. TONIGHT...AS DAYTIME HEATING SUBSIDES AND THE FRONT CONTINUES TO PUSH TO THE SOUTH...THE REMAINING PCPN SHOULD SHIFT TO THE SOUTH AND EAST AND DIMINISH. WITH LINGERING LOW LEVEL MOISTURE AND MID LEVEL DRYING...AREAS OF FOG ARE EXPECTED TO DEVELOP. THERE COULD ALSO BE SOME DRIZZLE NEAR THE WRN SHORE AS WEAK LOW LEVEL CONV DEVELOPS WITH MOIST NE FLOW OFF THE LAKE. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 505 AM EDT SUN JUL 7 2013 THE SURFACE FRONT WILL BE SOUTH OF THE FORECAST AREA MONDAY MORNING...WITH WEAK SURFACE RIDGING ACROSS LAKE SUPERIOR. THIS WILL HELP TO OVERALL DRY THE ATMOSPHERE...HOWEVER IT WILL ALSO ALLOW FOR WEAK UPSLOPE FLOW IN AREAS NEAR LAKE SUPERIOR. THE NAM AND EVEN THE GFS SUGGEST A VERY SHALLOW SATURATED LAYER BELOW 1000 FT WHICH WOULD IMPLY AT LEAST A CHANCE FOR LOW CLOUDS AND DRIZZLE NEAR LAKE SUPERIOR MONDAY MORNING. HOWEVER...BY AFTERNOON ANY LOW CLOUD/DRIZZLE SHOULD MIX OUT. WILL ALSO MAINTAIN THE SLIGHT CHANCE POPS IN THE LAKE BREEZE AREAS OF WESTERN UPPER MICHIGAN AND NEAR LAKE MICHIGAN. ALTHOUGH THE NWP SUGGESTS A FAIRLY DRY ATMOSPHERE BEHIND THE FRONT AND BROAD SCALE SUBSIDENCE...THE 850MB FRONT WILL STALL OUT OVER THE AREA AND INTERIOR INSTABILITY RISES TO NEARLY 1500 J/KG. NOT TO CONFIDENT THAT ANY SHOWERS/STORMS WILL OCCUR MONDAY AFTERNOON...BUT ALSO NOT CONFIDENT ENOUGH TO REMOVE THE MENTION. REGARDLESS...MONDAY WILL BE COOLER AND A LITTLE LESS HUMID THAN TODAY WITH READINGS NEAR LAKE SUPERIOR DROPPING BACK INTO THE LOWER-MID 70S. MONDAY NIGHT SHOULD BE A FAIRLY QUIET NIGHT ACROSS THE AREA AS THE NEXT LOW PRESSURE SYSTEM DEVELOPS ACROSS THE PLAINS. THE MODELS HAVE BACKED OFF ANY PCPN FOR THE AREA MONDAY NIGHT...INSTEAD FOCUSING IT ACROSS MN WHERE THE BETTER LOW LEVEL MOISTURE TRANSPORT AND DEEP MOISTURE WILL BE LOCATED. SOME DISAGREEMENT REMAINS REGARDING TIMING OF PRECIPITATION ON TUESDAY. THERE IS A HINT FROM THE ECMWF AND GFS THAT AN MCS WILL BE ONGOING TO WEST OF THE AREA IN THE BROAD WARM ADVECTION/ISENTROPIC LIFT AREA IN SRN MN. THIS LEADS TO MUCH UNCERTAINTY REGARDING CONVECTIVE EVOLUTION TUE FOR THE AREA. THE MAIN FORCING MECHANISM TUE AND TUE NIGHT WILL CONTINUE TO BE THE NRN STREAM ENERGY DIVING OUT OF CANADA AND AMPLIFYING DURING THE DAY...AND HAVE OPTED TO FOCUS ON THIS FEATURE SIMILAR TO THE NAM SOLUTION. WITH THE BEST FORCING WITH ENERGY BEING LATE TUE AFTN AND EVENING...HAVE OPTED TO MAINTAIN THE HIGHEST POPS DURING THIS PERIOD. DEPENDING ON THE AMOUNT OF DEBRIS CLOUDS...MODEST INSTABILITY IS POSSIBLE ACROSS THE AREA TUE AFTN/EVENING HELPING TO MAINTAIN THUNDERSTORM DEVELOPMENT ALONG THE FRONT. CANNOT TOTALLY RULE OUT SOME ORGANIZATION TO THE STORMS LATER TUESDAY INTO TUESDAY EVENING AS A COUPLED UPPER JET STRUCTURE DEVELOPS ACROSS THE NRN LAKES IN RESPONSE TO THE WAVE BECOMING NEGATIVELY TILTED. THE FRONT MOVES THROUGH THE AREA BY WEDNEDAY MORNING. MAY BE SOME RESIDUAL WRAP AROUND MOISTURE ACROSS THE AREA IN THE MORNING...BUT OTHERWISE THE WEATHER SHOULD IMPROVE DURING THE DAY. MODELS IN EXCELLENT AGREEMENT IN SHOWING BROAD HIGH PRESSURE ACROSS THE UPPER GREAT LAKES FOR THE END OF THE WEEK WITH RISING HEIGHTS BY THE WEEKEND. TEMPERATURES WILL BE SEASONABLE THU AND FRIDAY ALTHOUGH ABOVE NORMAL TEMPS MAY RETURN BY SATURDAY WITH 850MB TEMPS PROGGED TO RISE TO +16 ACROSS THE WEST. CANNOT RULE OUT SHOWERS SATURDAY AFTERNOON AS BOTH THE GFS AND ECMWF HINT AS AN UPPER WAVE MOVING THROUGH THE AREA IN THE WESTERLY FLOW. HOWEVER...AT THIS TIME WILL OPT TO MAINTAIN A DRY FORECAST. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 158 AM EDT SUN JUL 7 2013 LINE OF SHRA/TS NOW MOVING THRU WRN LK SUP WL IMPACT CMX/IWD EARLY THIS MRNG...LOWERING CONDITIONS TO MVFR AT LEAST BRIEFLY AS RA MOISTENED/LK COOLED AIR FOLLOWS INLAND. SAW SHOULD REMAIN DRY THRU SUNRISE WITH VFR CONDITIONS. SCT SHRA/PERHAPS A TS LIMITED BY DRYING ALF WL ARRIVE W-E ON SUN IN ADVANCE OF AN APRCHG COLD FNT. THE BEST CHC FOR THE TS WL BE AT SAW IN THE AFTN...BUT CONFIDENCE IN TIMING IS TOO LO TO INCLUDE IN THE TAF FOR NOW. SOME LO CLDS/MVFR CIGS ARE LIKELY TO FOLLOW THE FROPA THIS EVNG WITH DIURNAL COOLING AND UPSLOPE N-NW FLOW. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 505 AM EDT SUN JUL 7 2013 GIVEN EARLY SHIP OBSERVATIONS OF ZERO VISIBILITY OVER WESTERN LAKE SUPERIOR AND VERY HUMID AIRMASS OVER CHILLY WATER FOLLOWING SOME SHOWERS...A DENSE FOG ADVISORY WILL REMAIN IN EFFECT THIS MORNING FOR THE WEST HALF OF LAKE SUPERIOR. SOME DRYING ON SUNDAY AFTERNOON FOLLOWING A COLD FRONTAL PASSAGE SHOULD DISSIPATE THE THICKEST FOG. WINDS WILL REMAIN BELOW 15 KT ACROSS LAKE SUPERIOR THROUGH TUESDAY AS A WEAK SURFACE TROUGH DROPS SOUTHWARD ACROSS THE LAKE FOLLOWED BY AN AREA OF HIGH PRESSURE. WITH SHOWERS AND THUNDERSTORMS EARLY TODAY AND ADDITIONAL SCT SHRA/TSRA POSSIBLE THIS AFTERNOON...AREAS OF FOG WILL CONTINUE ACROSS THE LAKE. AS ANOTHER LOW DEVELOPS OVER THE PLAINS ON TUESDAY AND APPROACHES LAKE SUPERIOR ON WEDNESDAY....NORTHWESTERLY WINDS OF 15 TO 25 KNOTS WILL BE POSSIBLE BEHIND FOR A TIME WEDNESDAY AND WEDNESDAY NIGHT. A SURFACE HIGH MOVING OVER THE UPPER LAKES LATE IN THE WEEK WILL ALLOW LIGHT WINDS TO RETURN. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... DENSE FOG ADVISORY UNTIL 2 PM EDT /1 PM CDT/ THIS AFTERNOON FOR LSZ162-263-264. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...MRD AVIATION...KC MARINE...JLB
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
643 PM CDT MON JUL 8 2013 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 215 PM CDT MON JUL 8 2013 TONIGHT/S AND TUESDAY/S WX IS DEPENDENT ON THE EVOLUTION OF THE MCS/S OR DECAYING MCS/S ACROSS SD AND MT. INITIALLY...WEAK HIGH PRESSURE AND EARLIER STABLE CONDS BLW 3K...ALLOWED FOR STRATUS TO FORM OVERNIGHT...WHICH PERSISTENT THRU THE EARLY AFTN AS CLOSE AS WC WI. THE WEAKER WIND FIELD ACROSS WC WI WILL LIKELY ENHANCE THE FORMATION OF FOG/BR OVERNIGHT IN THE TYPICAL AREAS...AND MAY BE LOCALLY DENSE IF SKIES REMAIN CLR. AS FOR MN...SFC WINDS HAVE SHIFTED SLIGHTLY TO THE E/SE IN RESPONSE TO THE ANOTHER SHRTWV ACROSS THE SD. MAIN SFC BOUNDARY HAS STALLED IN CENTRAL IA THIS AFTN...WITH A FAIRLY POTENT SHRTWV NEAR OMA. THIS WILL ENHANCE LARGE SCALE LIFT AND CONVECTION ACROSS CENTRAL IA THIS AFTN. BASED ON THE E/SE FLOW DEVELOPING ACROSS SW MN...AS WELL AS ANOTHER DISTURBANCE MOVING ACROSS CENTRAL SD...ANOTHER AREA OF CONVECTION WILL LIKELY FORM IN CENTRAL/SE SD...AND MOVE ESE ACROSS FAR SW MN. HOW FAR NORTH THIS ACTIVITY MOVES IS DEPENDENT ON THE RETREAT OF THE STABLE CONDS IN PORTIONS OF CENTRAL/EC MN OVERNIGHT. BY TUESDAY MORNING...THE ATMOSPHERE ACROSS MN SHOULD HAVE DESTABILIZED ENOUGH FOR SHRA/TSRA ACROSS THE REGION. HOWEVER...LOW CONFIDENCE ON HOW WIDESPREAD THIS ACTIVITY WILL BE DUE TO INITIAL DRY ATMOSPHERE ABV 5K. OVERALL...SHRA/TSRA ACTIVITY SHOULD INCREASE TUESDAY...AND ESPECIALLY TUESDAY AFTN AS THE NEXT FRONTAL BOUNDARY HOLDS OFF ACROSS NW MN THRU THE EARLY AFTN. IN TERMS OF SVR WX...THE BEST SCENARIO WOULD BE SC/SE MN/WC WI TUESDAY AFTN AS THE FRONTAL BOUNDARY WILL BE NORTHWEST OF THIS REGION. OVERNIGHT CHC/S REMAIN UNCERTAIN DUE TO THE INITIAL STABLE CONDS AND THE FRONT STILL ACROSS IA DURING THE TYPICAL AFTN/EVENING HRS TODAY. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 345 PM CDT MON JUL 8 2013 DISTINCT NNE-SSW H5 TROF AXIS PUSHING THRU THE DAKOTAS WILL HELP PUSH A CDFNT THRU MN AND WI OVERNIGHT TUE INTO WED MRNG. CONVECTION WILL LIKELY BE ONGOING AT THE START OF THE PERIOD...EITHER IN CLUSTERS OF TSTMS OR POSSIBLY AS A STRONG-SEVERE MCS. CONTINUED HIGH INSTABILITY DUE TO A DEEP MOISTURE PROFILE ALONG WITH STRONG LOW- AND MID-LVL JETTING AND STEEP LAPSE RATES WILL CONTRIBUTE TO THE STRONG TSTM DEVELOPMENT. THE STORMS WILL EXIT THE MPX CWFA BY DAYBREAK WED MRNG. THE TROF AXIS WILL ALSO BE OVER THE GREAT LAKES BY WED MRNG...ALLOWING PRONOUNCED NW FLOW UNDERNEATH INCOMING HIGH PRES TO PREVAIL FOR WED AND THU. THE LOWER HEIGHTS AND NW FLOW WILL ALLOW FOR COOLER/DRIER CONDITIONS BOTH DAYS. HOWEVER...THE COOLDOWN WILL BE BRIEF AS MUCH HIGHER H5 HEIGHTS IN A BUILDING RIDGE MOVE ACRS THE AREA ON FRI...WHICH WILL LIKELY BRING A RETURN OF HIGHS IN THE MID-UPR 80S FOR MUCH OF THE AREA. ANOTHER FRONTAL SYSTEM WILL CROSS THE REGION OVER THE WEEKEND...WITH GREATEST CHC OF PRECIP FRI NIGHT INTO SAT MRNG. STILL TOO EARLY TO DETERMINE STORM STRENGTH BUT GIVEN THE RETURN OF HIGHER DEWPOINTS/INSTABILITY...ENHANCED JETTING AND ANOTHER CDFNT...STRONG STORMS CERTAINLY CANNOT BE RULED OUT. ANOTHER TRANQUIL PERIOD LOOKS TO COME OVER THE WEEKEND WITH WEAK HIGH PRES COMING ACROSS...BUT ISOLD SHWRS/TSTMS CANNOT BE RULED OUT HERE. HIGHS DROP TO THE UPR 70S/LWR 80S WED-THU THEN JUMP BACK INTO THE MID-UPR 80S FRI-SUN WITH DEWPOINTS RISING AS WELL. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING) ISSUED AT 602 PM CDT MON JUL 8 2013 SEVERAL CONCERNS FOR THE PERIOD AHEAD. THE FIRST IS CONVECTION DEVELOPING ALONG AND NORTH OF A STATIONARY FRONT NEAR THE NE/SD BORDER. HRRR PROJECTIONS OVER THE LAST SEVERAL RUNS REMAIN CONSISTENT ON BRINGING THE SHRA/TSRA INTO WEST CENTRAL AND SOUTHWEST MN BY 07Z. THIS ACTIVITY WOULD THEN REACH THE TWIN CITIES IN THE 10Z-12Z TIME FRAME. THE 18Z HOPWRF IS A LITTLE DIFFERENT WITH SCT SHRA/TSRA ACTUALLY DEVELOPING FROM KSTC TO KMSP BETWEEN 10Z AND 12Z. HENCE...THERE REMAINS UNCERTAINTY ON HOW THE CONVECTION UNFOLDS BUT THERE IS CERTAINLY A CHANCE DURING THE LATE EVENING AND OVERNIGHT HOURS AT THE MN TAF SITES. THE TENDENCY WOULD THEN BE FOR THE SHRA/TSRA TO WORK ACROSS KRNH AND KEAU DURING THE MORNING WHILE MORE ACTIVITY DEVELOPS BACK TO THE WEST ALONG AN APPROACHING COLD FRONT. SREF PROBABILITIES FOR MEASURABLE PRECIP TUE AFTERNOON ALONG AND AHEAD OF THE FRONT ARE VERY HIGH. VERY UNSTABLE CONDITIONS EXIST AND PROB30 GROUPS WERE INSERTED AT THE TAF SITES. INCREASING NW WINDS TUESDAY EVENING WITH THE ACTIVITY ENDING FROM WEST TO EAST. THE OTHER CONCERN TONIGHT IS THE POTENTIAL FOR BR/FG/STRATUS FROM KSTC THROUGH KRNH AND KEAU. BUFKIT FOG TECHNIQUE SHOWS THE HYDROLAPSE INCREASING WITH HEIGHT BUT THE AMOUNT OF MID/HIGH LEVEL CLOUDS ARRIVING OVERNIGHT MAY DAMPEN THE THREAT OF IFR OR LOWER BR/FG. THE HOPWRF PROBABILITIES ARE HIGHEST (30-40 PERCENT) FOR 3 MILES OR LOWER AT KSTC AND KEAU WITH KEAU HAVING ABOUT THE SAME PROBABILITY FOR LESS THAN 1 MILE. THEREFORE...LIMITED RESTRICTIONS TO THESE TWO SITES. KMSP...INCREASING MID/HIGH LEVEL CLOUDS THIS EVENING WITH THE THREAT FOR SHRA/TSRA BETWEEN 10Z AND 14Z. MVFR OR LOWER CONDITIONS IN THE SHRA/TSRA. SOME STRATUS UNDER 010 POSSIBLE DURING THE EARLY MORNING HOURS AS WELL BUT CONFIDENCE IS NOT HIGH ON WHETHER IT BECOMES A BKN-OVC DECK LIKE THIS PAST MORNING. MORE THUNDERSTORMS TUESDAY AFTERNOON AS A COLD FRONT MOVES IN. THE FRONT LIKELY REACHING THE AIRFIELD BETWEEN 10/01Z-02Z. PROB GROUP INSERTED FOR THUNDERSTORM CHANCES AHEAD OF THE FRONT. NW WINDS DEVELOPING IN THE WAKE OF THE FRONT TUESDAY EVENING ALONG WITH SHRA ENDING. /OUTLOOK FOR KMSP/ WED...VFR. WINDS NW 10G20KTS. THU...VFR. WINDS LGT AND VRB. FRI...VFR. WINDS S 10-15KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...JLT LONG TERM...JPC AVIATION...RAH
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1158 AM CDT SUN JUL 7 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 409 AM CDT SUN JUL 7 2013 A COUPLE OF WEAK BOUNDARIES OF CONCERN TO START THE DAY. ONE IS A TROUGH/COLD FRONT THAT AT 3 AM WAS ALONG THE ND/MN DOWN TO A WEAK LOW OVER NE SODAK...EXTENDING BACK SW INTO CENTRAL NEB. OTHER BOUNDARY IS A STATIONARY FRONT EXTENDING FROM AROUND MORRIS ACROSS CENTRAL MN INTO THE HAYWARD AREA. LLJ AND WAA REGIME NORTH OF THE STATIONARY BOUNDARY HAS GENERATED A CLUSTER OF STORMS OVER LAKE SUPERIOR THAT HAVE STAYED SAFELY AWAY FROM THE MPX AREA OVERNIGHT. FOR TODAY...THIS STATIONARY BOUNDARY WILL START TO LOOSE ITS DEFINITION AS IT SLOWLY SAGS SE. MOST DETERMINISTIC MODELS SAY TODAY WILL BE DRY AS GRADUAL HEIGHT RISES OVERTAKE THE AREA. HOWEVER...THE ZONAL FLOW OVER THE REGION TODAY LOOKS TO BE OF THE DIRTY VARIETY...WITH THE RAP/GFS/NAM SHOWING SMALL PERTURBATIONS CURRENTLY GENERATING STORMS OUT OVER MT/WY WORKING ACROSS MN DURING THE LATE AFTERNOON/EARLY EVENING. 07.00 NAM SOUNDINGS SHOW A RATHER UNSTABLE ENVIRONMENT BEING IN PLACE AS THESE WAVES APPROACH...WITH 2000-3000+ J/KG OF UNCAPPED SBCAPE BEING IN PLACE. AT THE SAME TIME...RAP SOUNDINGS ONLY ABLE TO GENERATE 1500 J/KG AT BEST. 700-500 MB LAPSE RATES ARE MEAGER ON BOTH /ABOUT 6 DEG C PER KM/...WITH THE DIFFERENCE COMING WITH HANDLING OF LOW LEVEL MOISTURE...AS THE RAP LOOKS A LITTLE AGGRESSIVE ON MIXING OUT DEWPS THIS AFTERNOON...WHICH IN TURN IS IMPACTING ITS INSTABILITY FORECAST. NAM IDEA IS PROBABLY MORE REALISTIC...BUT GIVEN MID-LEVEL LAPSE RATES...WOULD FAVOR 1500-2500 J/KG OF CAPE TO WORK WITH TODAY. WITH ALL THAT SAID...AT THE MOMENT ONLY HAVE CHANCE POPS MENTIONED IN THE FAR ERN CWA THIS AFTERNOON AS THIS IS WHERE SOME FORM OF LLJ FORCING LOOKS TO RESIDE...BUT GIVEN THE INSTABILITY MENTIONED ABOVE...COULD SEE STORMS DEVELOP ANYWHERE ALONG/SOUTH OF THE STATIONARY BOUNDARY. 03Z HOPWRF ENSEMBLE REFLECTIVITY FORECASTS HINT AT THIS HAPPENING...WITH SCATTERED CONVECTION SEEN AT 21Z ON MEMBERS 1/3/4 ACROSS MOST OF THE AREA. GUESS AT THIS POINT...THIS "WET PATTERN" THAT SET IN FRIDAY NIGHT HAS NOT EXACTLY PRODUCED MUCH IN THE WAY OF OBSERVABLE PRECIPITATION IN THE MPX AREA...SO AM A BIT GUN SHY ON GOING TO HIGH WITH POPS AT THIS POINT. WITH LOW LEVEL FLOW BACKING OFF CONSIDERABLY TODAY...LOW LEVEL SHEAR WILL BE PRETTY WEAK TODAY...BUT WITH INVERTED V SOUNDINGS SEEN IN MODELS...A CONDITIONAL WIND THREAT WOULD EXIST. FOR TONIGHT...LLJ FORCING AND THICKNESS PATTERN CONTINUE TO SHOW THE MPX AREA SPLIT BETWEEN BETTER REGIONS OF FORCING FOR CONVECTION OVER NRN IL/SRN WI AND OUT WEST ACROSS THE DAKOTAS...SO EXPECT TONIGHT TO BE DRY ONCE ANY DIURNALLY DRIVEN ACTIVITY DISSIPATES THIS EVENING. FOR TEMPERATURES...DENSE MID LEVEL CLOUD COVER SHOULD CLEAR ERN AREAS FAIRLY QUICKLY THIS MORNING...WITH A FAIR AMOUNT OF SUNSHINE EXPECTED AS A RESULT. AIR-MASS HAS CHANGED VERY LITTLE SINCE YESTERDAY...SO EXPECT HIGHS TO BE VERY SIMILAR TO WHAT WAS SEEN OUTSIDE OF CENTRAL MINNESOTA ON SATURDAY. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 409 AM CDT SUN JUL 7 2013 MAIN CHALLENGE IS TRYING TO PINPOINT THE TIMING AND PLACEMENT OF POPS EARLY IN THE WEEK BEFORE WE DRY OUT WEDNESDAY THROUGH FRIDAY. THE UPPER LEVEL RIDGE ANCHORED OVER THE DESERT SOUTHWEST WILL REMAIN THROUGHOUT THE PERIOD. MONDAY SHOULD START OUT DRY AS THE LOW LEVEL JET AS SEEN IN THE H925 WINDS AND MOISTURE TRANSPORT WILL REMAIN WELL SOUTH OF THE FORECAST AREA IN SOUTHERN IOWA/ILLINOIS. THE HUMID AIR-MASS WILL PERSIST ACROSS THE UPPER MIDWEST...AND WITH LITTLE MIXING EXPECTED ON MONDAY HAVE INCREASED DEW-POINTS INTO THE LOW 70S. BY MONDAY EVENING FORECAST MODELS INDICATE A SUBTLE H500 SHORTWAVE ROTATING AROUND THE PERIPHERY OF THE AFOREMENTIONED MONSOON RIDGE AND THIS SHOULD TRIGGER OFF SOME DEEP CONVECTION ON THE LEE SIDE OF THE ROCKIES WHICH WILL ADVECT EASTWARD OVER THE HIGH PLAINS OF THE DAKOTAS...AND COULD REACH THE CWA LATER MONDAY NIGHT INTO EARLY TUESDAY MORNING. THE 07.12 GFS AND ECMWF PLACE THE NOSE OF THE LOW LEVEL JET IN A FAVORABLE LOCATION FOR CONVECTION OVER THE MISSISSIPPI RIVER VALLEY. CURRENTLY HAVE THE HIGHEST POPS ALONG I90 NEAR THE IA BORDER...BUT THESE MAY NEED TO BE ADJUSTED NORTHWARD IF THE MODELS FOLLOW THE LEAD OF THE ECMWF...WHICH TAKES THE MCS ALONG AND NORTH OF I94. THERE WILL BE PLENTY OF INSTABILITY AS SREF PLUMES KEEP AROUND 1000 J/KG OF MUCAPE ACROSS THE REGION MONDAY NIGHT...WITH ROUGHLY 30KTS OF DEEP LAYER SHEAR DEPENDING ON THE PLACEMENT OF THE LLJ. THE FORECAST FOR TUESDAY BECOMES DIFFICULT SINCE MANY OF THE DETAILS HINGES DIRECTLY ON THE MESOSCALE FEATURES LEFT IN THE WAKE OF THE EARLY MORNING CONVECTION. A MORE WELL-DEFINED SHORTWAVE CURRENTLY OFF THE MOVING DOWN THE COAST OF BRITISH COLUMBIA WILL TRANSLATE EASTWARD IN THE ZONAL FLOW ALONG THE INTERNATIONAL BORDER AND ARRIVE ACROSS THE UPPER MIDWEST TUESDAY AFTERNOON. THIS WILL DRIVE A COLD FRONT THROUGH THE REGION ON TUESDAY...HOWEVER EXPECT ANY REMNANT DEBRIS CLOUDS TO CLEAR OFF ALLOWING THE BOUNDARY LAYER TO RECOVER DURING THE LATE MORNING HOURS...WITH AN UNSTABLE ENVIRONMENT SETTING UP ACROSS THE MN/WI BORDER BY TUESDAY AFTERNOON. AN H500 SPEED MAX OF 60KTS...ALONG WITH 3M/HR HEIGHT FALLS WILL PROVIDE SYNOPTIC SCALE FORCING FOR SEVERE THUNDERSTORMS AHEAD OF THE COLD FRONT. AS ALLUDED TO IN THE SPC DAY3 OUTLOOK...ANY OUTFLOW BOUNDARY PRODUCED BY THE EARLY MORNING CONVECTION WILL BE THE FOCUS FOR AN ENHANCED THREAT OF SEVERE WEATHER...INCLUDING TORNADOES AS THE SURFACE WINDS BACK AHEAD OF THE COLD FRONT. NAM BUFR SOUNDINGS FOR TUESDAY AFTERNOON AT KRWF SHOW A CYCLONICALLY CURVED HODOGRAPH WITH 0-3KM HELICITY OF OVER 300M2/S2. THE GFS IS FASTER WITH THE COLD FRONT...SO ITS LINEAR SHEAR PROFILE WITH NORTHWEST WIND IS LESS FAVORABLE FOR TORNADOES...BUT RATHER WOULD SUPPORT STRAIGHT LINE WINDS. REGARDLESS...TUESDAY SEVERE THREAT LOOKS TO BE THE MAIN CONCERN DURING THE EXTENDED. NORTHWEST FLOW IN THE WAKE OF THIS COLD FRONT WILL USHER IN DRIER AIR AS A CANADIAN HIGH PRESSURE BUILDS ON WEDNESDAY AND KEEPS THE REGION DRY THROUGH FRIDAY. HAVE INCREASED WINDS SLIGHTLY ABOVE GUIDANCE ON WEDNESDAY AS FORECAST SOUNDINGS SHOW ANOTHER GOOD MIXING DAY. LOOKING AHEAD...THE REPRIEVE FROM THE HEAT AND HUMIDITY WILL BE SHORT-LIVED AS THE THERMAL RIDGE DEVELOPS BY THE END OF THE WORK WEEK ACROSS THE HIGH PLAINS. WILL ACTUALLY SEE A WEST/EAST TEMPERATURE GRADIENT BY THE WEEKEND...WITH MUCH WARMER TEMPERATURES ACROSS WESTERN MINNESOTA. CURRENTLY HAVE MORE OF A BLENDED APPROACH WHICH YIELDS ONLY MID 80S ACROSS THE WEST. THERE IS STILL UNCERTAINTY...BUT IF THE H850 TEMPS REMAIN 20-22C WILL LIKELY SEE HIGHS IN THE MID 90S NEAR THE MN/SD BORDER. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 1140 AM CDT SUN JUL 7 2013 AS TYPICAL IN THE SUMMER...CONVECTION BEGINS TO DECREASE BY THE LATE MORNING AS LCL/S LIFT AND THE CAP STRENGTHENS. HOWEVER...IF ANY THUNDERSTORM COMPLEX CONTINUES THRU THE MID/LATE MORNING HRS AS IS THE COMPLEX IN NORTHERN SD...THE CHC/S OF IT CONTINUING THRU THE AFTN IS HIGH. THE ONLY PROBLEM IS A SFC BOUNDARY HAS MOVED INTO WESTERN MN TODAY. BUT...AT THE SAME TIME SFC MOISTURE HAS POOLED WHICH HAS ALLOWED FOR MLCAPES TO INCREASE. OVER THE PAST FEW HRS...THIS SFC BOUNDARY HAS NEARLY STALLED. THIS FRONT AND THE LEFTOVER CONVECTION ACROSS WC WI WILL LIKELY BE THE FOCUS FOR MORE SHRA/TSRA DEVELOPMENT THIS AFTN. THE ONLY PROBLEM NEAR MSP AND SOUTHWARD TO THE MN/IA BORDER...IS THE INCREASING CIN NOTED. THIS MAY HINDER ANY DEVELOPMENT IN THIS AREA...BUT WITH THE COMPLEX ACROSS SD MOVING EASTWARD THIS AFTN...IT WILL LIKELY MODIFIED THE ATMOSPHERE AND CAUSE MORE SHRA/TSRA THAN CURRENT MODELS INDICATE. BECAUSE OF THIS SCENARIO...WILL ADD VCSH TO ALL BUT AXN WHICH IS DEEPER IN THE N/NE FLOW AND K-INDEX VALUES ARE VERY LOW ATTM. RWF WILL LIKELY SEE VCSH BY 20-22Z...BUT TSRA CHC/S ARE TOO VARIABLE SO NOT ADDING VCTS ATTM. MSP/STC/RNH/EAU ALL HAVE LOW CHC/S OF SEEING CONVECTION THIS AFTN. HOW WIDESPREAD THE ACTIVITY GETS...REMAINS UNCERTAIN. WINDS WILL BE GENERALLY LIGHT AND VARIABLE WITH A MORE N/NE DIRECTION AT STC/AXN...AND MORE S/SW AT RNH/EAU/MSP/RWF. FOG/BR POTENTIAL IS ALSO GOOD OVERNIGHT WITH THE BOUNDARY NEAR THE AREA...AND LITTLE BOUNDARY LAYER MIXING. KMSP... THE FORECAST IS HIGHLY DEPENDENT ON HOW MUCH MIXING IN THE LOW LEVELS DEVELOP THIS AFTN AND WHETHER ENOUGH CIN TO LOWER CHC/S OF SHRA/TSRA. BASED ON THE LATEST REGIONAL RADAR/SFC BOUNDARY OUT WEST...AND THE CONTINUED TREND OF HIGH K-INDEX/S...WILL CONTINUE WITH VCSH...WITH THE BEST POTENTIAL OF SHRA/TSRA BETWEEN 23-02Z. AFT 2Z...THE PROBABILITY IS LOWER FOR SHRA/TSRA CHC/S...BUT WILL NEED TO WATCH WHAT HAPPENS WITH THE COMPLEX IN SD LATER THIS AFTN. WINDS WILL BE GENERALLY LIGHT SW THIS AFTN...LIGHT AND VARIABLE TONIGHT...WITH A LIGHT NE WIND MONDAY. /OUTLOOK FOR KMSP/ MONDAY NIGHT. CHC TSRA LATE NIGHT. WINDS E 5 KTS. TUE...TSRA LIKELY. VFR OUTSIDE OF TSRA. WINDS SE BCMG NW AT 5 KTS. WED...VFR. WINDS NW 10G20 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...MPG LONG TERM...JRB AVIATION...JLT
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
634 AM CDT SUN JUL 7 2013 .UPDATE... 12Z AVIATION DISCUSSION ADDED BELOW. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 409 AM CDT SUN JUL 7 2013 A COUPLE OF WEAK BOUNDARIES OF CONCERN TO START THE DAY. ONE IS A TROUGH/COLD FRONT THAT AT 3 AM WAS ALONG THE ND/MN DOWN TO A WEAK LOW OVER NE SODAK...EXTENDING BACK SW INTO CENTRAL NEB. OTHER BOUNDARY IS A STATIONARY FRONT EXTENDING FROM AROUND MORRIS ACROSS CENTRAL MN INTO THE HAYWARD AREA. LLJ AND WAA REGIME NORTH OF THE STATIONARY BOUNDARY HAS GENERATED A CLUSTER OF STORMS OVER LAKE SUPERIOR THAT HAVE STAYED SAFELY AWAY FROM THE MPX AREA OVERNIGHT. FOR TODAY...THIS STATIONARY BOUNDARY WILL START TO LOOSE ITS DEFINITION AS IT SLOWLY SAGS SE. MOST DETERMINISTIC MODELS SAY TODAY WILL BE DRY AS GRADUAL HEIGHT RISES OVERTAKE THE AREA. HOWEVER...THE ZONAL FLOW OVER THE REGION TODAY LOOKS TO BE OF THE DIRTY VARIETY...WITH THE RAP/GFS/NAM SHOWING SMALL PERTURBATIONS CURRENTLY GENERATING STORMS OUT OVER MT/WY WORKING ACROSS MN DURING THE LATE AFTERNOON/EARLY EVENING. 07.00 NAM SOUNDINGS SHOW A RATHER UNSTABLE ENVIRONMENT BEING IN PLACE AS THESE WAVES APPROACH...WITH 2000-3000+ J/KG OF UNCAPPED SBCAPE BEING IN PLACE. AT THE SAME TIME...RAP SOUNDINGS ONLY ABLE TO GENERATE 1500 J/KG AT BEST. 700-500 MB LAPSE RATES ARE MEAGER ON BOTH /ABOUT 6 DEG C PER KM/...WITH THE DIFFERENCE COMING WITH HANDLING OF LOW LEVEL MOISTURE...AS THE RAP LOOKS A LITTLE AGGRESSIVE ON MIXING OUT DEWPS THIS AFTERNOON...WHICH IN TURN IS IMPACTING ITS INSTABILITY FORECAST. NAM IDEA IS PROBABLY MORE REALISTIC...BUT GIVEN MID-LEVEL LAPSE RATES...WOULD FAVOR 1500-2500 J/KG OF CAPE TO WORK WITH TODAY. WITH ALL THAT SAID...AT THE MOMENT ONLY HAVE CHANCE POPS MENTIONED IN THE FAR ERN CWA THIS AFTERNOON AS THIS IS WHERE SOME FORM OF LLJ FORCING LOOKS TO RESIDE...BUT GIVEN THE INSTABILITY MENTIONED ABOVE...COULD SEE STORMS DEVELOP ANYWHERE ALONG/SOUTH OF THE STATIONARY BOUNDARY. 03Z HOPWRF ENSEMBLE REFLECTIVITY FORECASTS HINT AT THIS HAPPENING...WITH SCATTERED CONVECTION SEEN AT 21Z ON MEMBERS 1/3/4 ACROSS MOST OF THE AREA. GUESS AT THIS POINT...THIS "WET PATTERN" THAT SET IN FRIDAY NIGHT HAS NOT EXACTLY PRODUCED MUCH IN THE WAY OF OBSERVABLE PRECIPITATION IN THE MPX AREA...SO AM A BIT GUN SHY ON GOING TO HIGH WITH POPS AT THIS POINT. WITH LOW LEVEL FLOW BACKING OFF CONSIDERABLY TODAY...LOW LEVEL SHEAR WILL BE PRETTY WEAK TODAY...BUT WITH INVERTED V SOUNDINGS SEEN IN MODELS...A CONDITIONAL WIND THREAT WOULD EXIST. FOR TONIGHT...LLJ FORCING AND THICKNESS PATTERN CONTINUE TO SHOW THE MPX AREA SPLIT BETWEEN BETTER REGIONS OF FORCING FOR CONVECTION OVER NRN IL/SRN WI AND OUT WEST ACROSS THE DAKOTAS...SO EXPECT TONIGHT TO BE DRY ONCE ANY DIURNALLY DRIVEN ACTIVITY DISSIPATES THIS EVENING. FOR TEMPERATURES...DENSE MID LEVEL CLOUD COVER SHOULD CLEAR ERN AREAS FAIRLY QUICKLY THIS MORNING...WITH A FAIR AMOUNT OF SUNSHINE EXPECTED AS A RESULT. AIRMASS HAS CHANGED VERY LITTLE SINCE YESTERDAY...SO EXPECT HIGHS TO BE VERY SIMILAR TO WHAT WAS SEEN OUTSIDE OF CENTRAL MINNESOTA ON SATURDAY. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 409 AM CDT SUN JUL 7 2013 MAIN CHALLENGE IS TRYING TO PINPOINT THE TIMING AND PLACEMENT OF POPS EARLY IN THE WEEK BEFORE WE DRY OUT WEDNESDAY THROUGH FRIDAY. THE UPPER LEVEL RIDGE ANCHORED OVER THE DESERT SOUTHWEST WILL REMAIN THROUGHOUT THE PERIOD. MONDAY SHOULD START OUT DRY AS THE LOW LEVEL JET AS SEEN IN THE H925 WINDS AND MOISTURE TRANSPORT WILL REMAIN WELL SOUTH OF THE FORECAST AREA IN SOUTHERN IOWA/ILLINOIS. THE HUMID AIRMASS WILL PERSIST ACROSS THE UPPER MIDWEST...AND WITH LITTLE MIXING EXPECTED ON MONDAY HAVE INCREASED DEWPOINTS INTO THE LOW 70S. BY MONDAY EVENING FORECAST MODELS INDICATE A SUBTLE H500 SHORTWAVE ROTATING AROUND THE PERIPHERY OF THE AFOREMENTIONED MONSOON RIDGE AND THIS SHOULD TRIGGER OFF SOME DEEP CONVECTION ON THE LEE SIDE OF THE ROCKIES WHICH WILL ADVECT EASTWARD OVER THE HIGH PLAINS OF THE DAKOTAS...AND COULD REACH THE CWA LATER MONDAY NIGHT INTO EARLY TUESDAY MORNING. THE 07.12 GFS AND ECMWF PLACE THE NOSE OF THE LOW LEVEL JET IN A FAVORABLE LOCATION FOR CONVECTION OVER THE MISSISSIPPI RIVER VALLEY. CURRENTLY HAVE THE HIGHEST POPS ALONG I90 NEAR THE IA BORDER...BUT THESE MAY NEED TO BE ADJUSTED NORTHWARD IF THE MODELS FOLLOW THE LEAD OF THE ECMWF...WHICH TAKES THE MCS ALONG AND NORTH OF I94. THERE WILL BE PLENTY OF INSTABILITY AS SREF PLUMES KEEP AROUND 1000 J/KG OF MUCAPE ACROSS THE REGION MONDAY NIGHT...WITH ROUGHLY 30KTS OF DEEP LAYER SHEAR DEPENDING ON THE PLACEMENT OF THE LLJ. THE FORECAST FOR TUESDAY BECOMES DIFFICULT SINCE MANY OF THE DETAILS HINGES DIRECTLY ON THE MESOSCALE FEATURES LEFT IN THE WAKE OF THE EARLY MORNING CONVECTION. A MORE WELL-DEFINED SHORTWAVE CURRENTLY OFF THE MOVING DOWN THE COAST OF BRITISH COLUMBIA WILL TRANSLATE EASTWARD IN THE ZONAL FLOW ALONG THE INTERNATIONAL BORDER AND ARRIVE ACROSS THE UPPER MIDWEST TUESDAY AFTERNOON. THIS WILL DRIVE A COLD FRONT THROUGH THE REGION ON TUESDAY...HOWEVER EXPECT ANY REMNANT DEBRIS CLOUDS TO CLEAR OFF ALLOWING THE BOUNDARY LAYER TO RECOVER DURING THE LATE MORNING HOURS...WITH AN UNSTABLE ENVIRONMENT SETTING UP ACROSS THE MN/WI BORDER BY TUESDAY AFTERNOON. AN H500 SPEED MAX OF 60KTS...ALONG WITH 3M/HR HEIGHT FALLS WILL PROVIDE SYNOPTIC SCALE FORCING FOR SEVERE THUNDERSTORMS AHEAD OF THE COLD FRONT. AS ALLUDED TO IN THE SPC DAY3 OUTLOOK...ANY OUTFLOW BOUNDARY PRODUCED BY THE EARLY MORNING CONVECTION WILL BE THE FOCUS FOR AN ENHANCED THREAT OF SEVERE WEATHER...INCLUDING TORNADOES AS THE SURFACE WINDS BACK AHEAD OF THE COLD FRONT. NAM BUFR SOUNDINGS FOR TUESDAY AFTERNOON AT KRWF SHOW A CYCLONICALLY CURVED HODOGRAPH WITH 0-3KM HELICITY OF OVER 300M2/S2. THE GFS IS FASTER WITH THE COLD FRONT...SO ITS LINEAR SHEAR PROFILE WITH NORTHWEST WIND IS LESS FAVORABLE FOR TORNADOES...BUT RATHER WOULD SUPPORT STRAIGHT LINE WINDS. REGARDLESS...TUESDAY SEVERE THREAT LOOKS TO BE THE MAIN CONCERN DURING THE EXTENDED. NORTHWEST FLOW IN THE WAKE OF THIS COLD FRONT WILL USHER IN DRIER AIR AS A CANADIAN HIGH PRESSURE BUILDS ON WEDNESDAY AND KEEPS THE REGION DRY THROUGH FRIDAY. HAVE INCREASED WINDS SLIGHTLY ABOVE GUIDANCE ON WEDNESDAY AS FORECAST SOUNDINGS SHOW ANOTHER GOOD MIXING DAY. LOOKING AHEAD...THE REPRIEVE FROM THE HEAT AND HUMIDITY WILL BE SHORTLIVED AS THE THERMAL RIDGE DEVELOPS BY THE END OF THE WORK WEEK ACROSS THE HIGH PLAINS. WILL ACTUALLY SEE A WEST/EAST TEMPERATURE GRADIENT BY THE WEEKEND...WITH MUCH WARMER TEMPERATURES ACROSS WESTERN MINNESOTA. CURRENTLY HAVE MORE OF A BLENDED APPROACH WHICH YIELDS ONLY MID 80S ACROSS THE WEST. THERE IS STILL UNCERTAINTY...BUT IF THE H850 TEMPS REMAIN 20-22C WILL LIKELY SEE HIGHS IN THE MID 90S NEAR THE MN/SD BORDER. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 633 AM CDT SUN JUL 7 2013 AFTER ALMOST THE ENTIRE NIGHT...SHOWERS HAVE FINALLY STARTED BUILDING DOWN THE LLJ INTO WRN WI. THEY WILL BE FAST MOVING THOUGH AND OUT OF THE EAU AREA BY 14Z. AFTER THAT...WILL BE WAITING UNTIL ABOUT 22Z FOR WHEN NEXT CHANCE FOR TSRA DEVELOPS. CERTAINLY THE NAM WOULD CONTINUE TO LEAVE ONE TO BELIEVE AN AREA OF SCT STORMS COULD DEVELOP IN THE STC/MSP AREA THIS AFTERNOON...BUT CONFIDENCE NOT VERY HIGH IN THIS OCCURRING AT THE MOMENT AS MODELS HAVE BEEN A LITTLE OVER EXUBERANT IN GENERATING CONVECTION THE LAST COUPLE OF DAYS. TONIGHT WILL SEE SIMILAR CONDITIONS TO WHAT WAS SEEN LAST NIGHT OVER CENTRAL MN: CALM WINDS...MAINLY CLEAR SKIES...AND DEWPS UP AROUND 70. AS A RESULT...LAMP IS PRETTY AGGRESSIVE WITH KNOCKING VIS DOWN LATE SUNDAY NIGHT. HOWEVER...THIS MORNING WHERE DENSE FOG FORMED...HIGHS YESTERDAY WERE ONLY IN THE 70S...EXPECT UPPER 80S TO LOWER 90S EVERYWHERE TODAY...WHICH SHOULD LIMIT THE FG POTENTIAL TONIGHT TO MVFR...IFR AT WORSE. KMSP...OUTSIDE OF A SMALL CHANCE FOR TSRA BETWEEN ABOUT 22Z AND 02Z...THIS TAF PERIOD LOOKS DRY WITH VERY LIGHT WINDS. WITH CLEAR SKIES AND HIGH DEWP AIR IN PLACE...SHOULD START OF MONDAY MORNING QUITE HAZY...WITH POSSIBLY SOME FOG DOWN IN THE RIVER VALLEY...BUT THAT SHOULD BE IT FOR POTENTIAL RESTRICTIONS. /OUTLOOK FOR KMSP/ MON...MVFR VIS POSSIBLE EARLY. CHC TSRA LATE NIGHT. WINDS E 5 KTS. TUE...TSRA LIKELY. VFR OUTSIDE OF TSRA. WINDS SE BCMG NW AT 5 KTS. WED...VFR. WINDS NW 10G20 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...MPG LONG TERM...JRB AVIATION...MPG
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
416 AM CDT SUN JUL 7 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 409 AM CDT SUN JUL 7 2013 A COUPLE OF WEAK BOUNDARIES OF CONCERN TO START THE DAY. ONE IS A TROUGH/COLD FRONT THAT AT 3 AM WAS ALONG THE ND/MN DOWN TO A WEAK LOW OVER NE SODAK...EXTENDING BACK SW INTO CENTRAL NEB. OTHER BOUNDARY IS A STATIONARY FRONT EXTENDING FROM AROUND MORRIS ACROSS CENTRAL MN INTO THE HAYWARD AREA. LLJ AND WAA REGIME NORTH OF THE STATIONARY BOUNDARY HAS GENERATED A CLUSTER OF STORMS OVER LAKE SUPERIOR THAT HAVE STAYED SAFELY AWAY FROM THE MPX AREA OVERNIGHT. FOR TODAY...THIS STATIONARY BOUNDARY WILL START TO LOOSE ITS DEFINITION AS IT SLOWLY SAGS SE. MOST DETERMINISTIC MODELS SAY TODAY WILL BE DRY AS GRADUAL HEIGHT RISES OVERTAKE THE AREA. HOWEVER...THE ZONAL FLOW OVER THE REGION TODAY LOOKS TO BE OF THE DIRTY VARIETY...WITH THE RAP/GFS/NAM SHOWING SMALL PERTURBATIONS CURRENTLY GENERATING STORMS OUT OVER MT/WY WORKING ACROSS MN DURING THE LATE AFTERNOON/EARLY EVENING. 07.00 NAM SOUNDINGS SHOW A RATHER UNSTABLE ENVIRONMENT BEING IN PLACE AS THESE WAVES APPROACH...WITH 2000-3000+ J/KG OF UNCAPPED SBCAPE BEING IN PLACE. AT THE SAME TIME...RAP SOUNDINGS ONLY ABLE TO GENERATE 1500 J/KG AT BEST. 700-500 MB LAPSE RATES ARE MEAGER ON BOTH /ABOUT 6 DEG C PER KM/...WITH THE DIFFERENCE COMING WITH HANDLING OF LOW LEVEL MOISTURE...AS THE RAP LOOKS A LITTLE AGGRESSIVE ON MIXING OUT DEWPS THIS AFTERNOON...WHICH IN TURN IS IMPACTING ITS INSTABILITY FORECAST. NAM IDEA IS PROBABLY MORE REALISTIC...BUT GIVEN MID-LEVEL LAPSE RATES...WOULD FAVOR 1500-2500 J/KG OF CAPE TO WORK WITH TODAY. WITH ALL THAT SAID...AT THE MOMENT ONLY HAVE CHANCE POPS MENTIONED IN THE FAR ERN CWA THIS AFTERNOON AS THIS IS WHERE SOME FORM OF LLJ FORCING LOOKS TO RESIDE...BUT GIVEN THE INSTABILITY MENTIONED ABOVE...COULD SEE STORMS DEVELOP ANYWHERE ALONG/SOUTH OF THE STATIONARY BOUNDARY. 03Z HOPWRF ENSEMBLE REFLECTIVITY FORECASTS HINT AT THIS HAPPENING...WITH SCATTERED CONVECTION SEEN AT 21Z ON MEMBERS 1/3/4 ACROSS MOST OF THE AREA. GUESS AT THIS POINT...THIS "WET PATTERN" THAT SET IN FRIDAY NIGHT HAS NOT EXACTLY PRODUCED MUCH IN THE WAY OF OBSERVABLE PRECIPITATION IN THE MPX AREA...SO AM A BIT GUN SHY ON GOING TO HIGH WITH POPS AT THIS POINT. WITH LOW LEVEL FLOW BACKING OFF CONSIDERABLY TODAY...LOW LEVEL SHEAR WILL BE PRETTY WEAK TODAY...BUT WITH INVERTED V SOUNDINGS SEEN IN MODELS...A CONDITIONAL WIND THREAT WOULD EXIST. FOR TONIGHT...LLJ FORCING AND THICKNESS PATTERN CONTINUE TO SHOW THE MPX AREA SPLIT BETWEEN BETTER REGIONS OF FORCING FOR CONVECTION OVER NRN IL/SRN WI AND OUT WEST ACROSS THE DAKOTAS...SO EXPECT TONIGHT TO BE DRY ONCE ANY DIURNALLY DRIVEN ACTIVITY DISSIPATES THIS EVENING. FOR TEMPERATURES...DENSE MID LEVEL CLOUD COVER SHOULD CLEAR ERN AREAS FAIRLY QUICKLY THIS MORNING...WITH A FAIR AMOUNT OF SUNSHINE EXPECTED AS A RESULT. AIRMASS HAS CHANGED VERY LITTLE SINCE YESTERDAY...SO EXPECT HIGHS TO BE VERY SIMILAR TO WHAT WAS SEEN OUTSIDE OF CENTRAL MINNESOTA ON SATURDAY. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 409 AM CDT SUN JUL 7 2013 MAIN CHALLENGE IS TRYING TO PINPOINT THE TIMING AND PLACEMENT OF POPS EARLY IN THE WEEK BEFORE WE DRY OUT WEDNESDAY THROUGH FRIDAY. THE UPPER LEVEL RIDGE ANCHORED OVER THE DESERT SOUTHWEST WILL REMAIN THROUGHOUT THE PERIOD. MONDAY SHOULD START OUT DRY AS THE LOW LEVEL JET AS SEEN IN THE H925 WINDS AND MOISTURE TRANSPORT WILL REMAIN WELL SOUTH OF THE FORECAST AREA IN SOUTHERN IOWA/ILLINOIS. THE HUMID AIRMASS WILL PERSIST ACROSS THE UPPER MIDWEST...AND WITH LITTLE MIXING EXPECTED ON MONDAY HAVE INCREASED DEWPOINTS INTO THE LOW 70S. BY MONDAY EVENING FORECAST MODELS INDICATE A SUBTLE H500 SHORTWAVE ROTATING AROUND THE PERIPHERY OF THE AFOREMENTIONED MONSOON RIDGE AND THIS SHOULD TRIGGER OFF SOME DEEP CONVECTION ON THE LEE SIDE OF THE ROCKIES WHICH WILL ADVECT EASTWARD OVER THE HIGH PLAINS OF THE DAKOTAS...AND COULD REACH THE CWA LATER MONDAY NIGHT INTO EARLY TUESDAY MORNING. THE 07.12 GFS AND ECMWF PLACE THE NOSE OF THE LOW LEVEL JET IN A FAVORABLE LOCATION FOR CONVECTION OVER THE MISSISSIPPI RIVER VALLEY. CURRENTLY HAVE THE HIGHEST POPS ALONG I90 NEAR THE IA BORDER...BUT THESE MAY NEED TO BE ADJUSTED NORTHWARD IF THE MODELS FOLLOW THE LEAD OF THE ECMWF...WHICH TAKES THE MCS ALONG AND NORTH OF I94. THERE WILL BE PLENTY OF INSTABILITY AS SREF PLUMES KEEP AROUND 1000 J/KG OF MUCAPE ACROSS THE REGION MONDAY NIGHT...WITH ROUGHLY 30KTS OF DEEP LAYER SHEAR DEPENDING ON THE PLACEMENT OF THE LLJ. THE FORECAST FOR TUESDAY BECOMES DIFFICULT SINCE MANY OF THE DETAILS HINGES DIRECTLY ON THE MESOSCALE FEATURES LEFT IN THE WAKE OF THE EARLY MORNING CONVECTION. A MORE WELL-DEFINED SHORTWAVE CURRENTLY OFF THE MOVING DOWN THE COAST OF BRITISH COLUMBIA WILL TRANSLATE EASTWARD IN THE ZONAL FLOW ALONG THE INTERNATIONAL BORDER AND ARRIVE ACROSS THE UPPER MIDWEST TUESDAY AFTERNOON. THIS WILL DRIVE A COLD FRONT THROUGH THE REGION ON TUESDAY...HOWEVER EXPECT ANY REMNANT DEBRIS CLOUDS TO CLEAR OFF ALLOWING THE BOUNDARY LAYER TO RECOVER DURING THE LATE MORNING HOURS...WITH AN UNSTABLE ENVIRONMENT SETTING UP ACROSS THE MN/WI BORDER BY TUESDAY AFTERNOON. AN H500 SPEED MAX OF 60KTS...ALONG WITH 3M/HR HEIGHT FALLS WILL PROVIDE SYNOPTIC SCALE FORCING FOR SEVERE THUNDERSTORMS AHEAD OF THE COLD FRONT. AS ALLUDED TO IN THE SPC DAY3 OUTLOOK...ANY OUTFLOW BOUNDARY PRODUCED BY THE EARLY MORNING CONVECTION WILL BE THE FOCUS FOR AN ENHANCED THREAT OF SEVERE WEATHER...INCLUDING TORNADOES AS THE SURFACE WINDS BACK AHEAD OF THE COLD FRONT. NAM BUFR SOUNDINGS FOR TUESDAY AFTERNOON AT KRWF SHOW A CYCLONICALLY CURVED HODOGRAPH WITH 0-3KM HELICITY OF OVER 300M2/S2. THE GFS IS FASTER WITH THE COLD FRONT...SO ITS LINEAR SHEAR PROFILE WITH NORTHWEST WIND IS LESS FAVORABLE FOR TORNADOES...BUT RATHER WOULD SUPPORT STRAIGHT LINE WINDS. REGARDLESS...TUESDAY SEVERE THREAT LOOKS TO BE THE MAIN CONCERN DURING THE EXTENDED. NORTHWEST FLOW IN THE WAKE OF THIS COLD FRONT WILL USHER IN DRIER AIR AS A CANADIAN HIGH PRESSURE BUILDS ON WEDNESDAY AND KEEPS THE REGION DRY THROUGH FRIDAY. HAVE INCREASED WINDS SLIGHTLY ABOVE GUIDANCE ON WEDNESDAY AS FORECAST SOUNDINGS SHOW ANOTHER GOOD MIXING DAY. LOOKING AHEAD...THE REPRIEVE FROM THE HEAT AND HUMIDITY WILL BE SHORTLIVED AS THE THERMAL RIDGE DEVELOPS BY THE END OF THE WORK WEEK ACROSS THE HIGH PLAINS. WILL ACTUALLY SEE A WEST/EAST TEMPERATURE GRADIENT BY THE WEEKEND...WITH MUCH WARMER TEMPERATURES ACROSS WESTERN MINNESOTA. CURRENTLY HAVE MORE OF A BLENDED APPROACH WHICH YIELDS ONLY MID 80S ACROSS THE WEST. THERE IS STILL UNCERTAINTY...BUT IF THE H850 TEMPS REMAIN 20-22C WILL LIKELY SEE HIGHS IN THE MID 90S NEAR THE MN/SD BORDER. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 1247 AM CDT SUN JUL 7 2013 THUNDER THIS EVENING OVER LAKE SUPERIOR SITTING ON THE NOSE OF THE LLJ...AND EXPECT IT TO REMAIN IN THAT DIRECTION...SO HAVE REMOVED ANY MENTION OF PRECIP FROM TAFS. INSTEAD...CONCERN FOR TAFS IS THE POTENTIAL FOR FOG ACROSS WRN/CENTRAL MN AS MID LEVEL CLOUDS SLOWLY CLEAR OUT. UNDER THESE CLEAR SKIES...LIGHT WINDS WITH DEWPS IN THE UPPER 60S/LOWER 70S HAS ALREADY ALLOWED FAIRLY EXPANSIVE BR/FG TO DEVELOP FROM NRN BACK THRU WRN MN. ADDED SOME IFR VIS FOR AXN/STC...BUT THEY COULD END UP MUCH WORSE THAN THAT. FOR THE AFTERNOON...MODELS ARE NOT ALL THAT EXCITED ABOUT STORMS...BUT THE NAM/GFS SHOW A SHORT WAVE CURRENTLY OUT OVER WYOMING CROSSING MN DURING PEAK HEATING...AS THE WEAK SFC BOUNDARY SITS FROM SRN/ERN MN UP INTO NRN WI. THIS MAY ALLOW FOR ISO/SCT TSRA DEVELOPMENT LATE IN THE AFTERNOON FOR MSP/EAU/RNH. CONFIDENCE IN THIS HAPPENING IS LOW AT THE MOMENT...BUT WILL GIVE ME SOMETHING TO CHEW ON FOR THE 12Z TAFS. SUNDAY NIGHT WILL BE SIMILAR TO TONIGHT WITH LIGHT WINDS AND HIGH DEWPS...SO MAY HAVE TO BRING BACK SOME BR INTO THE TAFS AGAIN. KMSP...CONFIDENCE HIGH IN THE REST OF THE NIGHT BEING DRY AND VFR WITH S WINDS SLOWLY VEERING AS THEY SLACKEN OFF. THERE IS THE POTENTIAL FOR A STRAY THUNDERSTORM IN THE AREA SUN EVENING...MAINLY BETWEEN 22Z AND 02Z...BUT CONFIDENCE IN THEIR OCCURRENCE NOT HIGH ENOUGH TO INCLUDE IN THE TAF. BY MONDAY MORNING...WITH LIGHT WINDS AND HIGH DEWPS...MAY SEE VIS IN HZ/BR MAKE A RUN FOR 4 OR 5 SM MONDAY MORNING. /OUTLOOK FOR KMSP/ MON...MVFR VIS POSSIBLE EARLY. CHC TSRA LATE NIGHT. WINDS E 5 KTS. TUE...TSRA LIKELY. VFR OUTSIDE OF TSRA. WINDS SE BCMG NW AT 5 KTS. WED...VFR. WINDS NW 10-15 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...MPG LONG TERM...JRB AVIATION...MPG
AREA FORECAST DISCUSSION
NWS GLASGOW MT
850 PM MDT MON JUL 8 2013 .SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH WEDNESDAY... 900PM UPDATE... SEVERE THUNDERSTORM WATCH HAS BEEN DROPPED. MOST OF THE THUNDERSTORM ACTIVITY HAS BECOME SUB-SEVERE AND/OR IS EXITING THE CWA TO THE EAST. ONE FINAL ROUND OF SHOWERS AND THUNDERSTORMS IS APPROACHING PHILLIPS AND PETROLEUM COUNTIES AND WILL TRAVERSE THE CWA THROUGH THE OVERNIGHT HOURS IF IT HOLDS TOGETHER. NOT EXPECTING MUCH MORE SEVERE...BUT SOME ISOLATED SMALL HAIL AND GUSTY WINDS ARE POSSIBLE. THEREAFTER...UPPER LEVEL RIDGING BUILDS INTO NORTHEAST MONTANA BRINGING IN DRIER CONDITIONS UNDER LARGE SCALE SUBSIDENCE AND WARMING TEMPERATURES TOWARD THE MIDDLE OF THE WEEK. MALIAWCO 700PM UPDATE... SEVERE THUNDERSTORM WATCH HAS BEEN EXTENDED UNTIL 9PM FOR MCCONE AND PRAIRIE COUNTIES AND POINTS EASTWARD. THE MOST INTENSE STORMS LOOK TO HAVE JUST PUSHED OUTSIDE OF THE CWA. ANOTHER LINE OF SHOWERS AND STORMS EXISTS IN PRAIRIE COUNTY EXTENDING NORTHWARD THROUGH DANIELS AND SHERIDAN COUNTY. LOOKS LIKE IT HAS BECOME STABLE ENOUGH THOUGH THAT IN ROOSEVELT COUNTY AND AREAS NORTH...THAT THE MAIN CONCERN WILL ONLY BE A STEADY RAIN WITH SOME EMBEDDED THUNDER POSSIBLE. ANOTHER LINE OF SHOWERS/STORMS ACROSS CENTRAL MONTANA WILL MOVE THROUGH THE CWA BETWEEN NOW AND MIDNIGHT. DID NOT MAKE ANY REAL CHANGES TO THE GRIDS AT THIS TIME. POPS STILL LOOK OKAY AS THAT LAST ROUND OF SHOWERS/STORMS WILL LIKELY BE CONFINED TO EASTERN/CENTRAL ZONES AFTER MIDNIGHT. MALIAWCO 430PM UPDATE... SEVERE THUNDERSTORM WATCH WAS JUST EXTENDED TO INCLUDE DANIELS AND SHERIDAN COUNTIES UNTIL 7PM. FORECAST APPEARS ON TRACK SO NO OTHER CHANGES AT THIS TIME. SHOWERS AND THUNDERSTORMS WILL CONTINUE TO PUSH FROM WEST TO EAST ACROSS THE CWA THIS EVENING AND TONIGHT. SOME STORMS WILL PRODUCE LOCALLY HEAVY RAINFALL...VERY LARGE HAIL...AND STRONG WINDS. REPORTS OF GOLF BALL TO BASEBALL SIZED HAIL HAVE COME IN THIS EVENING WITH A STORM THAT PUSHED THROUGH NORTHEASTERN GARFIELD COUNTY AND INTO SOUTHERN MCCONE COUNTY. THIS STORM IS CURRENTLY THE STRONGEST STORM IN THE FORECAST REGION AND WILL BE MOVING SOUTHEAST INTO SOUTHERN DAWSON AND NORTHERN PRAIRIE COUNTIES. ADDITIONAL SHOWERS AND STORMS EXIST IN A LINE FROM JUST WEST OF THE PORT OF OPHEIM EXTENDING DOWN THROUGH PETROLEUM COUNTY. SOME OF THESE STORMS MAY BECOME SEVERE AS WELL AS THEY MARCH EASTWARD THROUGH THE EVENING. WILL UPDATE AS NEEDED. MALIAWCO MAIN FOCUS FOR THE SHORT TERM PERIOD IS A STRONG UPPER LEVEL SHORTWAVE FEATURE PUSHING INTO WESTERN MONTANA THIS AFTERNOON. OUT AHEAD OF THIS WAVE THERE IS ENOUGH INSTABILITY TO GENERATE SOME SHOWERS AND THUNDERSTORMS. FORECAST SOUNDINGS SHOW VERY GOOD CAPE/DIRECTIONAL WIND SHEAR PROFILES THROUGH TONIGHT AND PRECIPITABLE WATER VALUES OF GREATER THAN ONE INCH. ALSO GIVEN SEVERE THUNDERSTORM WATCH UNTIL 7PM FOR MOST OF THE CWA EXCEPT FOR DANIELS AND SHERIDAN COUNTIES...WILL NEED TO MONITOR FOR SOME STORMS TO PRODUCE LARGE HAIL...STRONG WINDS...AND VERY HEAVY RAINFALL. SPC STORM SCALE ENSEMBLE OF OPPORTUNITY PRODUCT SHOWS CONSISTENCY WITH LATEST HRRR AND NAM MODEL SOLUTIONS. EXPECT MOST OF THE ACTIVITY TO OCCUR PRIOR TO MIDNIGHT. BEYOND MIDNIGHT...CANNOT RULE OUT SHOWERS AND STORMS BUT THEY SHOULD REDUCE IN COVERAGE AND SEVERE POTENTIAL WILL LIKELY BE LIMITED BY THAT TIME. TUESDAY AND WEDNESDAY...ANY LEFTOVER SHOWERS AND THUNDERSTORMS WILL EXIT THE CWA DURING THE MORNING HOURS ON TUESDAY. THEREAFTER...MODELS DEPICT AN UPPER LEVEL RIDGE BUILDING INTO THE CWA WHICH WILL LEAD TO AN ABUNDANCE OF SUNSHINE...DRIER CONDITIONS...AND WARMING TEMPERATURES UNDER A REGIME OF LARGE SCALE SUBSIDENCE. DID NOT MAKE MANY CHANGES TO THIS PORTION OF THE FORECAST DUE TO THE PRIMARY CONCENTRATION ON THE SEVERE WEATHER POTENTIAL FOR THIS AFTERNOON INTO TONIGHT. WILL MAKE UPDATES AS NEEDED AS CONDITIONS WARRENT. MALIAWCO .LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY... SYNOPTIC SET UP... LONG TERM BEGINS WITH A LARGE HEAT DOME OVER THE DESERT SOUTHWEST AND INTERMOUNTAIN WEST. A RIDGE SPUR IS ANTICIPATED TO JUT OUT OF THE DOME OVER THE HIGH PLAINS OF MONTANA AND ALBERTA. A CLOSED LOW IS EXPECTED OVER THE COAST OF BRITISH COLUMBIA AND THE PACIFIC NORTHWEST. WEDNESDAY NIGHT INTO THURSDAY... DRY CONDITIONS ARE ANTICIPATED UNTIL THURSDAY AS NORTHEAST MONTANA COMES UNDER THE FULL OF AND INCREASING RIDGE. THURSDAY... THE AXIS OF THE RIDGE WILL PASS THROUGH AND ALLOW FOR A ISOLATED THUNDERSTORMS TO DEVELOP ON THE AXIS. THURSDAY ALSO LOOKS TO BE VERY WARM AHEAD OF THE AXIS WITH UPPER 90S AND POSSIBLE AS 850 MB TEMPERATURES REACH INTO THE 30* CELSIUS RANGE. THURSDAY NIGHT INTO SATURDAY...CLOSED LOW OVER THE PACIFIC NORTHWEST IS ANTICIPATED TO MOVE EAST THROUGH WEST MONTANA INTO THE HIGH PLAINS... EXITING THE RIDGE ALOFT OVER THE GREAT PLAINS. THIS WILL PLACE NORTHEAST MONTANA IN A SOUTHWEST FLOW WITH A WEAK TROUGHS AND SHORTWAVES MOVING THROUGH THE FLOW. A SHORTWAVE IS CURRENTLY TIMED ON FRIDAY WITH THE BASE OF THE LARGE TROUGH MOVING THROUGH SATURDAY HOWEVER... TIMING OF THESE WAVES COULD EASILY SHIFT AS THE LAST COUPLE RUNS HAVE ALREADY MOVED THEM AROUND. SATURDAY NIGHT ONWARD... THE TROUGH IS ANTICIPATED TO PASS OFF TO THE EAST AND REPRESS THE HEAT TO THE SOUTH WHILE A NEW RIDGE BUILDS OVER THE PACIFIC NORTHWEST. THIS WILL GENERATE ZONAL TO NORTHWEST FLOW ACROSS NORTHEAST MONTANA. CONDITIONS WILL BE DRY SLIGHTLY WITH A WEAK WARMING TREND. GAH && .AVIATION... VFR CONDITIONS WILL PREVAIL THROUGH THE TAF PERIOD. TEMPORARY REDUCTIONS IN VISIBILITIES ARE POSSIBLE IN HEAVIER SHOWERS AND THUNDERSTORMS OVERNIGHT...BUT THAT POTENTIAL WILL COME TO AN END...ESPECIALLY AFTER MIDNIGHT. DO EXPECT LIGHT WINDS OVERNIGHT FROM THE WEST TONIGHT AND BECOMING NORTHWEST ON TUESDAY. MALIAWCO && .GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE. && $$ WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS GLASGOW MT
706 PM MDT MON JUL 8 2013 .SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH WEDNESDAY... 700PM UPDATE... SEVERE THUNDERSTORM WATCH HAS BEEN EXTENDED UNTIL 9PM FOR MCCONE AND PRAIRIE COUNTIES AND POINTS EASTWARD. THE MOST INTENSE STORMS LOOK TO HAVE JUST PUSHED OUTSIDE OF THE CWA. ANOTHER LINE OF SHOWERS AND STORMS EXISTS IN PRAIRIE COUNTY EXTENDING NORTHWARD THROUGH DANIELS AND SHERIDAN COUNTY. LOOKS LIKE IT HAS BECOME STABLE ENOUGH THOUGH THAT IN ROOSEVELT COUNTY AND AREAS NORTH...THAT THE MAIN CONCERN WILL ONLY BE A STEADY RAIN WITH SOME EMBEDDED THUNDER POSSIBLE. ANOTHER LINE OF SHOWERS/STORMS ACROSS CENTRAL MONTANA WILL MOVE THROUGH THE CWA BETWEEN NOW AND MIDNIGHT. DID NOT MAKE ANY REAL CHANGES TO THE GRIDS AT THIS TIME. POPS STILL LOOK OKAY AS THAT LAST ROUND OF SHOWERS/STORMS WILL LIKELY BE CONFINED TO EASTERN/CENTRAL ZONES AFTER MIDNIGHT. MALIAWCO 430PM UPDATE... SEVERE THUNDERSTORM WATCH WAS JUST EXTENDED TO INCLUDE DANIELS AND SHERIDAN COUNTIES UNTIL 7PM. FORECAST APPEARS ON TRACK SO NO OTHER CHANGES AT THIS TIME. SHOWERS AND THUNDERSTORMS WILL CONTINUE TO PUSH FROM WEST TO EAST ACROSS THE CWA THIS EVENING AND TONIGHT. SOME STORMS WILL PRODUCE LOCALLY HEAVY RAINFALL...VERY LARGE HAIL...AND STRONG WINDS. REPORTS OF GOLF BALL TO BASEBALL SIZED HAIL HAVE COME IN THIS EVENING WITH A STORM THAT PUSHED THROUGH NORTHEASTERN GARFIELD COUNTY AND INTO SOUTHERN MCCONE COUNTY. THIS STORM IS CURRENTLY THE STRONGEST STORM IN THE FORECAST REGION AND WILL BE MOVING SOUTHEAST INTO SOUTHERN DAWSON AND NORTHERN PRAIRIE COUNTIES. ADDITIONAL SHOWERS AND STORMS EXIST IN A LINE FROM JUST WEST OF THE PORT OF OPHEIM EXTENDING DOWN THROUGH PETROLEUM COUNTY. SOME OF THESE STORMS MAY BECOME SEVERE AS WELL AS THEY MARCH EASTWARD THROUGH THE EVENING. WILL UPDATE AS NEEDED. MALIAWCO MAIN FOCUS FOR THE SHORT TERM PERIOD IS A STRONG UPPER LEVEL SHORTWAVE FEATURE PUSHING INTO WESTERN MONTANA THIS AFTERNOON. OUT AHEAD OF THIS WAVE THERE IS ENOUGH INSTABILITY TO GENERATE SOME SHOWERS AND THUNDERSTORMS. FORECAST SOUNDINGS SHOW VERY GOOD CAPE/DIRECTIONAL WIND SHEAR PROFILES THROUGH TONIGHT AND PRECIPITABLE WATER VALUES OF GREATER THAN ONE INCH. ALSO GIVEN SEVERE THUNDERSTORM WATCH UNTIL 7PM FOR MOST OF THE CWA EXCEPT FOR DANIELS AND SHERIDAN COUNTIES...WILL NEED TO MONITOR FOR SOME STORMS TO PRODUCE LARGE HAIL...STRONG WINDS...AND VERY HEAVY RAINFALL. SPC STORM SCALE ENSEMBLE OF OPPORTUNITY PRODUCT SHOWS CONSISTENCY WITH LATEST HRRR AND NAM MODEL SOLUTIONS. EXPECT MOST OF THE ACTIVITY TO OCCUR PRIOR TO MIDNIGHT. BEYOND MIDNIGHT...CANNOT RULE OUT SHOWERS AND STORMS BUT THEY SHOULD REDUCE IN COVERAGE AND SEVERE POTENTIAL WILL LIKELY BE LIMITED BY THAT TIME. TUESDAY AND WEDNESDAY...ANY LEFTOVER SHOWERS AND THUNDERSTORMS WILL EXIT THE CWA DURING THE MORNING HOURS ON TUESDAY. THEREAFTER...MODELS DEPICT AN UPPER LEVEL RIDGE BUILDING INTO THE CWA WHICH WILL LEAD TO AN ABUNDANCE OF SUNSHINE...DRIER CONDITIONS...AND WARMING TEMPERATURES UNDER A REGIME OF LARGE SCALE SUBSIDENCE. DID NOT MAKE MANY CHANGES TO THIS PORTION OF THE FORECAST DUE TO THE PRIMARY CONCENTRATION ON THE SEVERE WEATHER POTENTIAL FOR THIS AFTERNOON INTO TONIGHT. WILL MAKE UPDATES AS NEEDED AS CONDITIONS WARRENT. MALIAWCO .LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY... SYNOPTIC SET UP... LONG TERM BEGINS WITH A LARGE HEAT DOME OVER THE DESERT SOUTHWEST AND INTERMOUNTAIN WEST. A RIDGE SPUR IS ANTICIPATED TO JUT OUT OF THE DOME OVER THE HIGH PLAINS OF MONTANA AND ALBERTA. A CLOSED LOW IS EXPECTED OVER THE COAST OF BRITISH COLUMBIA AND THE PACIFIC NORTHWEST. WEDNESDAY NIGHT INTO THURSDAY... DRY CONDITIONS ARE ANTICIPATED UNTIL THURSDAY AS NORTHEAST MONTANA COMES UNDER THE FULL OF AND INCREASING RIDGE. THURSDAY... THE AXIS OF THE RIDGE WILL PASS THROUGH AND ALLOW FOR A ISOLATED THUNDERSTORMS TO DEVELOP ON THE AXIS. THURSDAY ALSO LOOKS TO BE VERY WARM AHEAD OF THE AXIS WITH UPPER 90S AND POSSIBLE AS 850 MB TEMPERATURES REACH INTO THE 30* CELSIUS RANGE. THURSDAY NIGHT INTO SATURDAY...CLOSED LOW OVER THE PACIFIC NORTHWEST IS ANTICIPATED TO MOVE EAST THROUGH WEST MONTANA INTO THE HIGH PLAINS... EXITING THE RIDGE ALOFT OVER THE GREAT PLAINS. THIS WILL PLACE NORTHEAST MONTANA IN A SOUTHWEST FLOW WITH A WEAK TROUGHS AND SHORTWAVES MOVING THROUGH THE FLOW. A SHORTWAVE IS CURRENTLY TIMED ON FRIDAY WITH THE BASE OF THE LARGE TROUGH MOVING THROUGH SATURDAY HOWEVER... TIMING OF THESE WAVES COULD EASILY SHIFT AS THE LAST COUPLE RUNS HAVE ALREADY MOVED THEM AROUND. SATURDAY NIGHT ONWARD... THE TROUGH IS ANTICIPATED TO PASS OFF TO THE EAST AND REPRESS THE HEAT TO THE SOUTH WHILE A NEW RIDGE BUILDS OVER THE PACIFIC NORTHWEST. THIS WILL GENERATE ZONAL TO NORTHWEST FLOW ACROSS NORTHEAST MONTANA. CONDITIONS WILL BE DRY SLIGHTLY WITH A WEAK WARMING TREND. GAH && .AVIATION... VFR. ISOLATED THUNDERSTORMS CAN BE EXPECTED OFF AND ON THROUGH THE DAY WITH FEW SIGNIFICANT IMPACTS THROUGH 18Z. 21Z-06Z...HOWEVER A LINE OR COMPLEX OF SEVERE THUNDERSTORMS IS EXPECTED TO ROLL ACROSS NORTHEAST MONTANA. 23-01Z FOR KGGW... 00Z-02Z FOR KOLF... AND 01-03Z FOR KSDY/KGDV BASED ON THE CURRENT GUIDANCE. DO EXPECT SIGNIFICANT IMPACTS TO FLIGHT OPERATIONS LATE THIS AFTERNOON AND THROUGH THE EVENING HOURS WITH THESE THUNDERSTORMS. PROTON && .GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE. && $$ WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS BILLINGS MT
407 PM MDT SUN JUL 7 2013 .SHORT TERM...VALID FOR MON AND TUE... MAIN FORECAST ISSUE IS SEVERE WX POTENTIAL THIS AFTERNOON/EVENING AND AGAIN TOMORROW. WATER VAPOR IMAGERY SHOWS WSW FLOW ALOFT WITH SHORTWAVE ENERGY APPROACHING FROM THE GREAT BASIN. A STRONGER TROF CAN BE SEEN ALONG THE PAC NW COAST...AND THIS FEATURE WILL BE A PLAYER FOR US MONDAY AND MONDAY NIGHT. PWATS IN PLACE ARE QUITE HIGH AND IN THE VICINITY OF AN INCH...PERHAPS A BIT HIGHER IN OUR EAST. LOW LEVEL E-SE WINDS ARE INCREASING...PROVIDING GREATER SHEAR AND LOW LEVEL MOISTURE THAN WE SAW ON SATURDAY...AND LATEST 850MB ANALYSIS SUGGESTS NOSE OF 850MB DEWPTS TO +13C IN FAR SE MT. WE REMAIN UNDER RRQ OF 60KT H3 JET TO OUR NORTH...THUS MODEST SYNOPTIC ASCENT IS PRESENT. OVERALL INGREDIENTS ARE IN PLACE FOR SEVERE WEATHER LATE THIS AFTN AND EVENING. RECENT HRRR RUNS AGREE WITH THIS ASSESSMENT AND HAVE BEEN CONSISTENT. CONVECTION BEGINNING TO INITIATE OVER OUR SW MTNS WITH A FEW LIGHTNING STRIKES NOTED SOUTH OF LIVINGSTON. A LONE CELL HAS EMERGED FROM THE CU FIELD SE OF BROADUS. WILL BE INTERESTING TO SEE WHAT SERN CELL WILL DO OVER THE NEXT COUPLE HOURS...SFC TEMPS NEAR THE MID 80S MAY BE ENOUGH TO BREAK CAP THAT HAS BEEN IN PLACE. OTHERWISE FOCUS SHOULD BE IN OUR WEST AS ACTIVITY SPREADS OFF THE HIGH TERRAIN...SHIFTING EAST OVER TIME. GREATEST SEVERE POTENTIAL THIS AFTN AND EVENING WILL BE EAST OF BILLINGS IN REGION OF GREATER INSTABILITY AND SHEAR...ESPECIALLY AS LOW LEVEL JET KICKS IN THIS EVENING. FOR MONDAY...OUR ENTIRE AREA WILL BE AT AN ELEVATED RISK FOR SEVERE STORMS DUE TO COMBINATION OF ASCENT FROM PAC NW TROF AND SURFACE COLD FRONT. LARGE HAIL AND DAMAGING WINDS MAIN THREATS. HEAVY RAIN WILL CONTINUE TO BE A POSSIBILITY BOTH TODAY AND TOMORROW DUE TO THE MOISTURE RICH AIRMASS IN PLACE. PASSAGE OF TROF...SURGE OF DRIER AIR AND SHIFT TO NW FLOW ALOFT WILL SIGNAL THE BEGINNINGS OF A PATTERN SHIFT ON TUESDAY...AS THE MOIST AIRMASS FINALLY GETS CLEANED OUT. COULD BE SOME MORNING SHOWERS ON TUESDAY ALONG PV MAX...BUT OTHERWISE EXPECT DRIER AND MORE STABLE CONDITIONS AS COOLER SFC RIDGE BUILDS IN FROM THE NW. HAVE LOWERED POPS TUESDAY AFTERNOON AND NIGHT. AS FOR TEMPS...MONDAY WILL BE THE WARMER OF THE NEXT TWO DAYS... WITH PREFRONTAL CONDITIONS PERHAPS ALLOWING FOR TEMPS NEAR 90F. TUESDAY WILL BE POSTFRONTAL AND COOLER WITH UPPER 70S TO MID 80S FOR HIGHS...OR A LITTLE BELOW NORMAL. JKL .LONG TERM...VALID FOR WED...THU...FRI...SAT...SUN... MINIMAL CHANGES TO THE EXTENDED PERIOD...DUE IN LARGE PART TO MODEL INCONSISTENCY FOR LATTER PORTIONS OF THE PERIOD. THE PERIOD BEGINS WED UNDER AN UPPER LEVEL RIDGE...SO EXPECT HOT AND MAINLY DRY CONDITIONS. MODELS DO SHOW SOME SHORTWAVE ACTIVITY ROUNDING THE RIDGE...WITH SE LOW LEVEL FLOW OVER SOUTHEAST MONTANA LATE WED AFTN/EVE...SO I KEPT A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS IN THE FORECAST ACROSS THE SE. RIDGING DOMINATES THROUGH MUCH OF THE DAY THURS...SO HOT AND DRY CONDITIONS WILL AGAIN BE THE RULE. A WEAK COLD FRONT...ALONG WITH SHORTWAVE ACTIVITY...WILL MOVE ACROSS THE REGION THURS NIGHT...SO WE MAY SEE SOME CONVECTIVE ACTIVITY THURS EVE/NIGHT OVER THE WESTERN MOUNTAINS...AND OVER THE EAST...WHERE SHEAR IS BETTER AND THE ATMOSPHERE IS LESS CAPPED. FRI LOOKS TO BE A TAD COOLER BEHIND THE FRONT...BUT STILL QUITE WARM. MODEL SOLUTIONS DIVERGE SAT AND SUN. THE ECMWF BRINGS ANOTHER COLD FRONT THROUGH THE REGION SAT AND KEEP THE REGION UNDER THE INFLUENCE OF A WEAK UPPER LEVEL TROF SUN. MEANWHILE...THE GFS KEEPS THE AREA MAINLY UNDER THE INFLUENCE OF SOUTHWESTERLY FLOW ALOFT AROUND AN UPPER LEVEL RIDGE. BECAUSE OF THE LARGE MODEL DIFFERENCES...I LEFT THE FORECAST FROM SAT TO THE END OF THE EXTENDED PRETTY MUCH AS I INHERITED IT. TEMPS WED AND THURS LOOK TO BE IN THE MID 80S TO MID 90S...WITH SLIGHTLY COOLER WEATHER FRI. NOT QUITE SURE WHAT TEMPS WILL BE SAT AND SUN. IF THE GFS IS CORRECT...UPPER 80S TO 90S. IF THE ECMWF IS CORRECT...UPPER 70S TO MID 80S. FOR NOW...KEPT SAT AND SUN TEMPS IN THE MID 80S TO AROUND 90...SORT OF A BLEND OF THE GFS AND ECMWF. STC && .AVIATION... THUNDERSTORMS WILL CONTINUE TO DEVELOP ACROSS SOUTHERN AND WESTERN PORTIONS OF THE REGION...AND MOVE EASTWARD THROUGH THE LATE AFTERNOON/EVENING HOURS. SOME OF THE STORMS WILL CONTAIN HAIL AND ERRATIC...GUSTY WINDS AND HEAVY PRECIP...WHICH MAY PRODUCE BRIEF IFR/LIFR FLIGHT CONDITIONS. VFR CONDITIONS WILL PREVAIL OUTSIDE OF THUNDERSTORMS. MORE THUNDERSTORMS ARE ANTICIPATED ACROSS THE REGION TOMORROW AFTERNOON/EVENING AHEAD OF A COLD FRONT. STC && .PRELIMINARY POINT TEMP/POPS... MON TUE WED THU FRI SAT SUN ----------------------------------------------------------- BIL 062/089 061/084 059/091 064/094 064/090 061/091 060/089 43/T 32/T 11/U 11/B 22/T 22/T 22/T LVM 053/088 050/085 048/091 056/094 052/090 051/091 050/089 43/T 31/B 11/U 11/B 22/T 22/T 22/T HDN 060/091 061/085 056/092 064/095 064/091 061/092 060/090 43/T 32/T 11/U 11/B 22/T 22/T 22/T MLS 065/088 062/084 059/092 066/095 063/090 062/091 061/089 44/T 53/T 11/U 12/T 22/T 22/T 22/T 4BQ 061/090 060/084 056/090 062/093 063/089 061/090 060/088 53/T 43/T 11/U 12/T 22/T 22/T 33/T BHK 060/084 060/079 055/086 061/089 063/085 062/086 061/084 54/T 54/T 12/T 22/T 22/T 22/T 33/T SHR 056/090 056/083 052/089 059/093 058/089 056/090 055/088 43/T 32/T 11/U 11/U 22/T 22/T 22/T && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...SEVERE THUNDERSTORM WATCH 396 IN EFFECT UNTIL 11 PM MDT THIS EVENING FOR ZONES 28>42-56>58-63>68. WY...SEVERE THUNDERSTORM WATCH 396 IN EFFECT UNTIL 11 PM MDT THIS EVENING FOR ZONES 98-99. && $$ WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS BILLINGS MT
221 PM MDT SUN JUL 7 2013 .SHORT TERM...VALID FOR MON AND TUE... MAIN FORECAST ISSUE IS SEVERE WX POTENTIAL THIS AFTERNOON/EVENING AND AGAIN TOMORROW. WATER VAPOR IMAGERY SHOWS WSW FLOW ALOFT WITH SHORTWAVE ENERGY APPROACHING FROM THE GREAT BASIN. A STRONGER TROF CAN BE SEEN ALONG THE PAC NW COAST...AND THIS FEATURE WILL BE A PLAYER FOR US MONDAY AND MONDAY NIGHT. PWATS IN PLACE ARE QUITE HIGH AND IN THE VICINITY OF AN INCH...PERHAPS A BIT HIGHER IN OUR EAST. LOW LEVEL E-SE WINDS ARE INCREASING...PROVIDING GREATER SHEAR AND LOW LEVEL MOISTURE THAN WE SAW ON SATURDAY...AND LATEST 850MB ANALYSIS SUGGESTS NOSE OF 850MB DEWPTS TO +13C IN FAR SE MT. WE REMAIN UNDER RRQ OF 60KT H3 JET TO OUR NORTH...THUS MODEST SYNOPTIC ASCENT IS PRESENT. OVERALL INGREDIENTS ARE IN PLACE FOR SEVERE WEATHER LATE THIS AFTN AND EVENING. RECENT HRRR RUNS AGREE WITH THIS ASSESSMENT AND HAVE BEEN CONSISTENT. CONVECTION BEGINNING TO INITIATE OVER OUR SW MTNS WITH A FEW LIGHTNING STRIKES NOTED SOUTH OF LIVINGSTON. A LONE CELL HAS EMERGED FROM THE CU FIELD SE OF BROADUS. WILL BE INTERESTING TO SEE WHAT SERN CELL WILL DO OVER THE NEXT COUPLE HOURS...SFC TEMPS NEAR THE MID 80S MAY BE ENOUGH TO BREAK CAP THAT HAS BEEN IN PLACE. OTHERWISE FOCUS SHOULD BE IN OUR WEST AS ACTIVITY SPREADS OFF THE HIGH TERRAIN...SHIFTING EAST OVER TIME. GREATEST SEVERE POTENTIAL THIS AFTN AND EVENING WILL BE EAST OF BILLINGS IN REGION OF GREATER INSTABILITY AND SHEAR...ESPECIALLY AS LOW LEVEL JET KICKS IN THIS EVENING. FOR MONDAY...OUR ENTIRE AREA WILL BE AT AN ELEVATED RISK FOR SEVERE STORMS DUE TO COMBINATION OF ASCENT FROM PAC NW TROF AND SURFACE COLD FRONT. LARGE HAIL AND DAMAGING WINDS MAIN THREATS. HEAVY RAIN WILL CONTINUE TO BE A POSSIBILITY BOTH TODAY AND TOMORROW DUE TO THE MOISTURE RICH AIRMASS IN PLACE. PASSAGE OF TROF...SURGE OF DRIER AIR AND SHIFT TO NW FLOW ALOFT WILL SIGNAL THE BEGINNINGS OF A PATTERN SHIFT ON TUESDAY...AS THE MOIST AIRMASS FINALLY GETS CLEANED OUT. COULD BE SOME MORNING SHOWERS ON TUESDAY ALONG PV MAX...BUT OTHERWISE EXPECT DRIER AND MORE STABLE CONDITIONS AS COOLER SFC RIDGE BUILDS IN FROM THE NW. HAVE LOWERED POPS TUESDAY AFTERNOON AND NIGHT. AS FOR TEMPS...MONDAY WILL BE THE WARMER OF THE NEXT TWO DAYS... WITH PREFRONTAL CONDITIONS PERHAPS ALLOWING FOR TEMPS NEAR 90F. TUESDAY WILL BE POSTFRONTAL AND COOLER WITH UPPER 70S TO MID 80S FOR HIGHS...OR A LITTLE BELOW NORMAL. JKL .LONG TERM...VALID FOR WED...THU...FRI...SAT...SUN... MINIMAL CHANGES TO THE EXTENDED PERIOD...DUE IN LARGE PART TO MODEL INCONSISTENCY FOR LATTER PORTIONS OF THE PERIOD. THE PERIOD BEGINS WED UNDER AN UPPER LEVEL RIDGE...SO EXPECT HOT AND MAINLY DRY CONDITIONS. MODELS DO SHOW SOME SHORTWAVE ACTIVITY ROUNDING THE RIDGE...WITH SE LOW LEVEL FLOW OVER SOUTHEAST MONTANA LATE WED AFTN/EVE...SO I KEPT A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS IN THE FORECAST ACROSS THE SE. RIDGING DOMINATES THROUGH MUCH OF THE DAY THURS...SO HOT AND DRY CONDITIONS WILL AGAIN BE THE RULE. A WEAK COLD FRONT...ALONG WITH SHORTWAVE ACTIVITY...WILL MOVE ACROSS THE REGION THURS NIGHT...SO WE MAY SEE SOME CONVECTIVE ACTIVITY THURS EVE/NIGHT OVER THE WESTERN MOUNTAINS...AND OVER THE EAST...WHERE SHEAR IS BETTER AND THE ATMOSPHERE IS LESS CAPPED. FRI LOOKS TO BE A TAD COOLER BEHIND THE FRONT...BUT STILL QUITE WARM. MODEL SOLUTIONS DIVERGE SAT AND SUN. THE ECMWF BRINGS ANOTHER COLD FRONT THROUGH THE REGION SAT AND KEEP THE REGION UNDER THE INFLUENCE OF A WEAK UPPER LEVEL TROF SUN. MEANWHILE...THE GFS KEEPS THE AREA MAINLY UNDER THE INFLUENCE OF SOUTHWESTERLY FLOW ALOFT AROUND AN UPPER LEVEL RIDGE. BECAUSE OF THE LARGE MODEL DIFFERENCES...I LEFT THE FORECAST FROM SAT TO THE END OF THE EXTENDED PRETTY MUCH AS I INHERITED IT. TEMPS WED AND THURS LOOK TO BE IN THE MID 80S TO MID 90S...WITH SLIGHTLY COOLER WEATHER FRI. NOT QUITE SURE WHAT TEMPS WILL BE SAT AND SUN. IF THE GFS IS CORRECT...UPPER 80S TO 90S. IF THE ECMWF IS CORRECT...UPPER 70S TO MID 80S. FOR NOW...KEPT SAT AND SUN TEMPS IN THE MID 80S TO AROUND 90...SORT OF A BLEND OF THE GFS AND ECMWF. STC && .AVIATION... THUNDERSTORMS WILL CONTINUE TO DEVELOP ACROSS SOUTHERN AND WESTERN PORTIONS OF THE REGION...AND MOVE EASTWARD THROUGH THE LATE AFTERNOON/EVENING HOURS. SOME OF THE STORMS WILL CONTAIN HAIL AND ERRATIC...GUSTY WINDS AND HEAVY PRECIP...WHICH MAY PRODUCE BRIEF IFR/LIFR FLIGHT CONDITIONS. VFR CONDITIONS WILL PREVAIL OUTSIDE OF THUNDERSTORMS. MORE THUNDERSTORMS ARE ANTICIPATED ACROSS THE REGION TOMORROW AFTERNOON/EVENING AHEAD OF A COLD FRONT. STC && .PRELIMINARY POINT TEMP/POPS... MON TUE WED THU FRI SAT SUN ----------------------------------------------------------- BIL 062/089 061/084 059/091 064/094 064/090 061/091 060/089 43/T 32/T 11/U 11/B 22/T 22/T 22/T LVM 053/088 050/085 048/091 056/094 052/090 051/091 050/089 43/T 31/B 11/U 11/B 22/T 22/T 22/T HDN 060/091 061/085 056/092 064/095 064/091 061/092 060/090 43/T 32/T 11/U 11/B 22/T 22/T 22/T MLS 065/088 062/084 059/092 066/095 063/090 062/091 061/089 44/T 53/T 11/U 12/T 22/T 22/T 22/T 4BQ 061/090 060/084 056/090 062/093 063/089 061/090 060/088 53/T 43/T 11/U 12/T 22/T 22/T 33/T BHK 060/084 060/079 055/086 061/089 063/085 062/086 061/084 54/T 54/T 12/T 22/T 22/T 22/T 33/T SHR 056/090 056/083 052/089 059/093 058/089 056/090 055/088 43/T 32/T 11/U 11/U 22/T 22/T 22/T && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...NONE. WY...NONE. && $$ WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS HASTINGS NE
638 PM CDT MON JUL 8 2013 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 455 PM CDT MON JUL 8 2013 PLENTY OF THINGS TO PONDER DURING THE NEXT 24 HOURS...INCLUDING AT LEAST ONE CONDITIONAL RISK FOR SEVERE STORMS THIS EVENING...AND MAYBE ANOTHER SEVERE RISK ON TUESDAY AFTERNOON/EVENING...ALTHOUGH CONFIDENCE IS QUITE LOW ON THE LIKELIHOOD/EVOLUTION OF THE LATTER. IN OTHER DEPARTMENTS...TOMORROW IS CURRENTLY EXPECTED TO BE THE OVERALL-HOTTEST AFTERNOON OF THE SUMMER SO FAR FOR MOST OF THE CWA...AND A HEAT ADVISORY HAS BEEN ISSUES FOR SEVERAL SOUTHERN/SOUTHEAST COUNTIES. 21Z OBJECTIVE SURFACE ANALYSIS HIGHLIGHTS A SOMEWHAT SUBTLE-BUT EVIDENT EAST-WEST QUASI STATIONARY GENERALLY STRETCHED ACROSS THE SOUTHERN HALF OF NEBRASKA. IN THE WIND-FIELD...THIS BOUNDARY SEPARATES A STEADY 15+ MPH SOUTHERLY BREEZE IN NORTH CENTRAL KANSAS...FORM A LIGHTER...GENERALLY EAST-SOUTHEAST BREEZE WITHIN MOST OF THE NEBRASKA CWA. ITS ALSO SOMEWHAT OF A MOISTURE BOUNDARY...WITH MID-50S TO LOW 60S DEWPOINTS RESIDING IN THE DEEPLY MIXED AIRMASS TO THE SOUTH...AND HIGHER DEWPOINTS MID-60S TO NEAR 70 MOST AREAS ALONG/NORTH OF I-80. AS DISCUSSED EARLIER TODAY...NEAR-CRITICAL FIRE DANGER WILL PERSIST FOR A FEW MORE HOURS ESPECIALLY IN THE PHILLIPS/ROOKS COUNTY AREA IN KS. HIGH TEMPS THIS AFTERNOON WORKED OUT PRETTY WELL ACROSS THE SOUTHWESTERN 2/3 OF THE CWA RANGING GENERALLY 95-104 DEGREES...WHILE SOME NORTHEAST AREAS ARE STRUGGLING TO REACH 90 THANKS IN PART TO A BATCH OF MID LEVEL CLOUDS THAT FORMED ON THE BACK-SIDE OF AN MCV THAT HAS MOVED WELL EAST INTO WESTERN IA. ALOFT...WATER VAPOR IMAGERY AND SHORT TERM MODEL DATA CONFIRM CONTINUED QUASI-ZONAL FLOW ACROSS THE LOCAL AREA...BETWEEN THE LARGER-SCALE MID LEVEL RIDGE AXIS STRETCHED WEST-EAST FROM AZ TO OK...AND A VIGOROUS SHORTWAVE TROUGH MAKING ITS WAY ACROSS THE ID/MT/CANADA BORDER AREA. THE MAIN LOW-AMPLITUDE SHORTWAVE TROUGH OF INTEREST FOR THIS EVENING IS CURRENTLY LIFTING OUT OF WY INTO WESTERN NEB/SD. LATE THIS AFTERNOON INTO THIS EVENING...THE PRIMARY FOCUS IS ON HOW MUCH THUNDERSTORM COVERAGE THE CWA WILL SEE...AND WHETHER SOME OF THIS ACTIVITY COULD BECOME SEVERE. AT PRESENT TIME...RADAR INDICATES A FEW WEAK-ISH/HIGH-BASED STORMS NEAR THE STATE LINE IN THE SOUTHWESTERN CWA...LARGELY A RESULT OF VERY STEEP LOW-LEVEL LAPSE RATES IN THE HOT/DEEPLY MIXED AIRMASS OVER KS. MEANWHILE...OFF TO THE NORTHWEST...A FEW STRONG TO SEVERE STORMS HAVE TAKEN OFF IN NORTH CENTRAL/WESTERN NEB...IN AN ENVIRONMENT CHARACTERIZED BY AROUND 2000+ J/KG MLCAPE AND 30+ KNOTS OF 0-6KM DEEP LAYER SHEAR. LOCALLY...WITH THE EXCEPTION OF THE HIGH-BASED STORMS IN OUR SOUTH...MODEL SOUNDINGS SUGGEST THERE IS JUST ENOUGH OF A CAP IN PLACE TO KEEP CONVECTION FROM DEVELOPING OVERHEAD IN MOST OF THE CENTRAL/NORTHERN CWA...AIDED IN PART BY SUBSIDENCE BEHIND THE DEPARTING MCV. AS HAS BEEN THE CASE FOR DAYS NOW...CONFIDENCE IN THE DETAILS IS LOW IN THIS WEAKLY FORCED PATTERN...BUT TAKING CUE FROM THE LATEST RAP/HRRR AND 12Z 4KM WRF- NMM...THE GENERAL EXPECTATION IS FOR MOST OF THE CWA TO REMAIN STORM FREE THROUGH AT LEAST 00Z/7PM...BEFORE STORM CHANCES GRADUALLY INCREASE THROUGH THE EVENING HOURS ESPECIALLY NEAR/NORTH OF I-80...AND LIKELY MAINLY AS A FUNCTION OF ACTIVITY MOVING IN FROM WESTERN NEBRASKA...ALTHOUGH LOCAL INITIATION NEAR THE SURFACE BOUNDARY CANNOT BE RULED OUT EITHER. BOTH THE WRF-NMM AND HRRR ARE FAIRLY AGGRESSIVE BRINGING A CLUSTER OF STORMS...POSSIBLY A SEMI- ORGANIZED MCS ACROSS ESPECIALLY THE NORTHERN 1/2 OF THE CWA THIS EVENING...BUT A SIMILAR MODEL DEPICTION YESTERDAY ENDED UP BEING A BIT OVERDONE...AND THUS HAVE CAPPED POPS AT NO HIGHER THAN 50 PERCENT AT LEAST FOR NOW. WITH MLCAPE REMAINING 1000+ J/KG WELL INTO THE EVENING HOURS AND WITH AT LEAST MODEST SHEAR...AT LEAST A LOCALIZED LARGE HAIL AND ESPECIALLY A WIND THREAT IS QUITE POSSIBLE ESPECIALLY IF STORMS TO THE WEST CAN ORGANIZE AND DEVELOP A COLD POOL. AGREE WITH SPC IN HIGHLIGHTING THE NORTHERN 1/2 OF THE CWA FOR THE GREATEST SEVERE THREAT...BUT JUST CANNOT RULE OUT A STRONG TO SEVERE STORM ANYWHERE IN THE CWA THIS EVENING. ALTHOUGH THE MAIN SEVERE THREAT SHOULD BE ON THE WANE BY MIDNIGHT...LINGERED LOW POPS THROUGH THE NIGHT ESPECIALLY ACROSS THE EASTERN 2/3 OF THE CWA TO ACCOUNT FOR ACTIVITY PERSISTING OR NEWLY-DEVELOPING WITHIN THE LOW LEVEL JET AXIS...AND JUST AHEAD ON APPROACHING COLD FRONT. IF NOTHING ELSE...HOPEFULLY PARTS OF THE CWA CAN RECEIVE SOME MUCH-NEEDED RAINS TONIGHT...BECAUSE THIS MAY BE ONE OF THE BETTER CHANCES FOR AWHILE. TEMPERATURE-WISE...MADE ONLY MINOR TWEAKS TO LOWS...WITH THE PREVALENT LIGHT SOUTHERLY BREEZE HOLDING MOST AREAS UP INTO THE 70-75 RANGE. ALTHOUGH AT LEAST LIGHT FOG DEVELOPMENT CANNOT BE RULED OUT LATE TONIGHT ESPECIALLY IN AREAS THAT RECEIVE RAIN...THE PROBABILITY/MAGNITUDE SEEMED LOW ENOUGH TO OMIT FROM THE FORECAST. TURNING TO TUESDAY DAYTIME...REALLY DON/T THINK SEVERE STORMS ARE GOING TO END UP BEING MUCH OF A STORY...AT LEAST THROUGH THE VAST MAJORITY OF THE DAY. ALOFT...QUASI-ZONAL FLOW WILL START TO TURN A BIT MORE NORTHWESTERLY IN RESPONSE TO THE PASSAGE OF A FAIRLY VIGOROUS SHORTWAVE TROUGH FROM EASTERN MT TOWARD NORTHERN MN. AT THE SURFACE...A FAIRLY WEAK COLD FRONT...MORE EVIDENT IN THE WIND FIELD THAN ON A THERMOMETER...WILL WORK SOUTHWARD ACROSS THE CWA AS THE DAY WEARS ON...WITH MOST AREAS SEEING A FEW HOURS OF LIGHT/VARIABLE WINDS BEFORE A SLIGHTLY MORE STEADY NORTHERLY BREEZE SETTLES IN. ALONG AND ESPECIALLY JUST AHEAD OF THIS BOUNDARY...A LOW LEVEL THERMAL RIDGE WILL EXTEND INTO THE CWA FROM THE SOUTHWEST...PROMOTING WHAT SHOULD BE THE HIGHEST HEAT-INDEX READINGS OF THE SUMMER SO FAR FOR MOST ALL OF THE CWA...AND IN SOME SPOTS THE HOTTEST ACTUAL AIR TEMPERATURES. THE ONLY CAVEATS WOULD BE AN UNEXPECTEDLY STRONG OUTFLOW BOUNDARY FROM CONVECTION TONIGHT THAT MIGHT HELP ACCELERATE THE COLD FRONT SOUTHWARD FASTER...AND MAYBE A DENSER-THAN-EXPECTED COVERAGE OF MID LEVEL CLOUDS OR LINGERING WEAK CONVECTION. BUT ASSUMING NEITHER ONE OF THESE CAVEATS PLAY OUT...HAVE AIMED FOR ACTUAL HIGH TEMPS RANGING FROM MID 90S NORTH...UPPER 90S CENTRAL...AND 100-106 NEAR AND SOUTH OF THE STATE LINE. HEAT INDEX VALUES OF 100+ ARE FORECAST ACROSS MUCH OF THE SOUTHERN AND EASTERN HALVES OF THE CWA...AND HAVE ISSUED A HEAT ADVISORY FOR ALL KS ZONES ALONG WITH WEBSTER- NUCKOLLS-THAYER IN NEBRASKA...WHICH HAVE THE HIGHEST LIKELIHOOD OF REACHING OR EXCEEDING A 105 HEAT INDEX. FORTUNATELY FOR FIRE WEATHER CONCERNS IN THE FAR SOUTHWEST COUNTIES...SUSTAINED WINDS/GUSTS DO NOT LOOK TO EXCEED 20 MPH DURING THE PEAK OF AFTERNOON HEATING. AS FOR CONVECTIVE CHANCES...FORECAST SOUNDINGS SUGGEST THAT A FAIRLY STRONG CAP SHOULD PREVAIL THROUGH THE DAY AS VERY WARM MID LEVEL TEMPS OVERSPREAD THE AREA. AS A RESULT...OTHER THAN A LINGERING SLIGHT CHANCE OF MORNING STORMS IN EASTERN COUNTIES RIGHT AWAY IN THE MORNING...WILL AIM FOR A DRY MAJORITY OF THE DAY...BEFORE BRINGING BACK SLIGHT STORM CHANCES POST- 21Z/4PM. THERE ARE AT LEAST TWO POSSIBLE FOCUSES FOR LATE AFTERNOON DEVELOPMENT...THE MAIN COLD FRONT WHICH SHOULD BE VERY NEAR THE FAR SOUTHEAST CORNER OF THE CWA...AND ALSO FORCING FROM THE SOUTHERN EDGE OF THE NORTHERN PLAINS SHORTWAVE TROUGH...WHICH COULD KICK OFF CONVECTION CLOSER TO THE NORTHERN EDGE OF THE CWA. HOWEVER...MODELS SUCH AS THE 12Z 4KM WRF-NMM ADVERTISE ESSENTIALLY NO LATE AFTERNOON STORMS ANYWHERE IN THE CWA...SO THUS ONLY THE SLIGHT POPS. IF STORMS WOULD MANAGE TO FORM...A CONDITIONAL SEVERE THREAT COULD EXIST ALMOST ANYWHERE IN THE CWA...POTENTIALLY EVEN WEST OF THE SPC DAY 2 SLIGHT RISK AREA. PLENTY OF UNCERTAINTY FOR SURE. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 455 PM CDT MON JUL 8 2013 MAIN FORECAST CONCERNS WILL BE CHANCES FOR THUNDERSTORMS TUESDAY NIGHT AND WEDNESDAY NIGHT AND AGAIN SATURDAY NIGHT THROUGH MONDAY AND TEMPERATURES. MODELS ARE FAIRLY SIMILAR IN BUILDING AN UPPER LEVEL RIDGE ACROSS THE AREA DURING THE PERIOD...BUT THE DETAILS OF THE TIMING MAINLY WEAK UPPER LEVEL WAVES THROUGH THE AREA ARE SOMEWHAT DIFFERENT BETWEEN THE MODELS. THIS BRINGS SOME UNCERTAINTY IN WHEN THERE WILL BE SOME CHANCES FOR THUNDERSTORMS. A SURFACE COLD FRONT WILL MOVE TO THE SOUTH ACROSS THE SOUTHERN PART OF THE FORECAST AREA DURING THE EVENING. AN UPPER LEVEL WAVE WILL ALSO BE MOVING THROUGH THE AREA. EXPECT SOME THUNDERSTORMS ALONG THAT BOUNDARY DURING THE EVENING...BUT OVERNIGHT THEY SHOULD MOVE OUT OF THE AREA. MUCAPE IS THE HIGHEST DURING THE EARLY EVENING HOURS AND DIMINISHES SOME LATER IN THE EVENING...BUT STILL REMAINS AROUND 2500 J/KG. EXPECT THAT THERE COULD BE SOME SEVERE WEATHER DURING THE EVENING. A COOL SURFACE HIGH PRESSURE SYSTEM SETTLES INTO THE AREA ON WEDNESDAY. HIGH TEMPERATURES WILL BE AROUND 10 DEGREES COOLER THAN ON TUESDAY. WEDNESDAY SHOULD REMAIN DRY...BUT AN UPPER LEVEL WAVE MOVES ACROSS THE RIDGE AND THERE COULD BE SOME ISOLATED SHOWERS AND THUNDERSTORMS THAT MOVE OFF THE HIGH PLAINS DURING THE NIGHT TIME HOURS. THE SURFACE HIGH MOVES OFF TO THE EAST ON THURSDAY AND THE SURFACE PRESSURE GRADIENT TIGHTENS. WINDS AT 850MB ARE ONLY 20 TO 25 KTS SO EXPECT SOME BREEZY CONDITIONS. WITH WINDS FROM THE SOUTH THE TEMPERATURES WILL WARM UP. THE UPPER LEVEL RIDGE CONTINUES TO BUILD ACROSS THE AREA FOR THE PERIOD THURSDAY THROUGH SATURDAY. EXPECT TEMPERATURES TO WARM A LITTLE EACH DAY THROUGH THE PERIOD. THE UPPER LEVEL RIDGE REMAINS IN PLACE FOR SATURDAY NIGHT THROUGH MONDAY...BUT IT IS MORE OF AN UPPER LEVEL HIGH PRESSURE SYSTEM ACROSS THE AREA. IT IS FAIRLY BROAD AND THERE ARE A FEW UPPER LEVEL WAVES THAT MOVE THROUGH THE AREA. SIMILAR TO THE PAST WEEK OR SO EACH OF THESE UPPER LEVEL WAVES HAS A CHANCE FOR SOME THUNDERSTORMS. DO NOT EXPECT THAT IT WILL BE WIDESPREAD OR THAT EVERYONE WILL HAVE SOME PRECIPITATION. THE TIMING AND THE LOCATION OF ANY PRECIPITATION IS IN QUESTION. WITH A FEW MORE CLOUDS AND THE CHANCE FOR SOME PRECIPITATION THE TEMPERATURES WILL BE A LITTLE COOLER. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING) ISSUED AT 625 PM CDT MON JUL 8 2013 PRIMARY CONCERNS FOR THIS TAF PERIOD LIE WITH PRECIPITATION CHANCES THIS EVENING/OVERNIGHT...THEN THE PASSAGE OF A COLD FRONTAL BOUNDARY TOMORROW. HAVE ALREADY SEEN A CLUSTER OF SHOWERS/THUNDERSTORMS DEVELOP OFF TO THE SOUTHWEST OF THE TERMINAL AREA...BUT CONFIDENCE IN THAT ACTIVITY DRIFTING UP TO AFFECT THE TERMINAL IS NOT HIGH ENOUGH TO INSERT ANY TEMPO GROUP OR PREVAILING MENTION...BUT WILL BE KEEPING A CLOSE EYE ON IT. STILL SEEING THE POTENTIAL FOR ACTIVITY FROM THE WEST TO SLIDE EAST ACROSS THE REGION LATER ON...AND WILL KEEP THE VCTS MENTION GOING. WINDS LOOK TO BECOME MORE SOUTHERLY WITH TIME THIS EVENING...AND WILL REMAIN THAT WAY UNTIL CLOSER TO MIDDAY TOMORROW...WHEN WINDS GRADUALLY BECOME MORE WESTERLY AHEAD OF AN APPROACHING FRONT. MODELS NOT IN TOO BAD OF AGREEMENT WITH THE TIMING ARND 18Z...WITH NORTHWEST WINDS BUILDING IN BEHIND THROUGH THE REMAINDER OF THE TAF PERIOD. && .GID WATCHES/WARNINGS/ADVISORIES... NE...HEAT ADVISORY FROM NOON TO 7 PM CDT TUESDAY FOR NEZ085>087. KS...HEAT ADVISORY FROM NOON TO 7 PM CDT TUESDAY FOR KSZ005>007- 017>019. && $$ SHORT TERM...PFANNKUCH LONG TERM...JCB AVIATION...ADO
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1258 PM CDT SUN JUL 7 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 311 AM CDT SUN JUL 7 2013 IF MOISTURE CAN REMAIN IN PLACE THIS MORNING THEN ANOTHER ROUND OF THUNDERSTORMS COULD DEVELOP THIS AFTERNOON AND TONIGHT. THE DISTURBANCE AND ONGOING STORM ACTIVITY ACROSS WESTERN NEB SHOULD EXIT THE FCST AREA TO EAST BY 20Z. THIS IMPLIES THAT THE STORMS WEAKEN AND FALL APART AS THEY MOVE EAST AS INDICATED BY THE HRRR. DEEP EASTERLIES SHOULD CONTINUE TODAY AS INDICATED BY THE VWP AT KUDX AND THIS WOULD SUPPORT DESTABILIZATION ACROSS WESTERN NEB LATE THIS MORNING THROUGH THIS EVENING WHICH IN TURN WOULD PROPAGATE EAST THROUGH THE FCST AREA. THE FCST MIGHT BE AMBITIOUS WITH THE 40 POPS BUT THIS IS A MARK DOWN FROM A 5 MODEL BLEND OF THE ECM...GFS...SREF...NAM AND GEMREG. WATER VAPOR SUGGESTS ANOTHER DISTURBANCE ACROSS WRN WY AND NRN UT WHICH COULD COME ACROSS THIS AFTERNOON ON THE HEALS OF THE ONGOING DISTURBANCE. MODEST DEEP LAYER SHEAR UP TO 250 MB WOULD PERHAPS SUPPORT ISOLATED SEVERE STORMS WHICH WOULD PROBABLY PULSE SEVERE FROM TIME TO TIME THIS AFTERNOON AND THIS EVENING. THE WEAKNESS IN THE LOW LEVEL WINDS SUGGESTS THIS BEHAVIOR. SPC SUGGESTED A WEAKLY ORGANIZED MCS MIGHT DEVELOP AND THIS CERTAINLY APPEARS IN LINE WITH THE 21Z OUTPUT OF THE 06Z HRRR SHOWING A FAIRLY ORGANIZED LINE OF STORMS FROM KOGA TO KVTN. HIGHS IN THE UPPER 80S TO MID 90S ARE EXPECTED TODAY. THE MODELS HAVE COME IN A FEW DEGREES COOLER FOR HIGHS TODAY VERSUS SATURDAY. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 311 AM CDT SUN JUL 7 2013 ACTIVE FIRST HALF OF THE WEEK EXPECTED...AS THE AREA REMAINS ON THE NORTHERN SIDE OF LARGE RIDGE OF UPPER HIGH PRESSURE CENTERED ACROSS THE FOUR CORNERS REGION. WINDS ALOFT...MOISTURE...AND INSTABILITY WILL BE FAVORABLE FOR TSTMS UNTIL THE RIDGE BEGINS TO BUILD NORTH OVER THE AREA BY WEEKS END. TEMPERATURES ALOFT WILL WARM THEN AS WELL AS A DECREASE IN WINDS ALOFT...CONDITIONS LESS FAVORABLE FOR TSTM DEVELOPMENT. A STATIONARY FRONT WILL OSCILLATE NORTH AND SOUTH THE FIRST HALF OF THE WEEK...AND WILL BE A FOCUS FOR STORM DEVELOPMENT. OTHER STORMS MAY FORM OFF THE HIGHER TERRAIN TO OUR WEST AND MOVE EAST INTO THE AREA DURING THE EVENING HOURS. PWATS WILL BE RATHER HIGH...WITH PLENTY OF LOW LEVEL MOISTURE IN PLACE TOO...SO SOME DECENT RAINFALL TOTALS ARE POSSIBLE. TEMPERATURES WILL BE WARM...AND THEN TURNING HOT BY WEEKS END AS THE RIDGE BUILDS NORTH OVER THE AREA. HIGHS IN THE UPPER 80S TO MID 90S WILL START THE WEEK...WITH MID 90S TO AROUND 100 TO FINISH THE WEEK. DEPENDING ON DEW POINTS...WHICH CURRENTLY LOOK TO REMAIN HIGH EAST OF HIGHWAY 83 AS THE HEAT BUILDS IN BY THE END OF THE WEEK...WE COULD BE FLIRTING WITH HEAT ADVISORY CONDITIONS. WILL CONTINUE TO MONITOR. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 1257 PM CDT SUN JUL 7 2013 SMALL AREA OF SHOWERS AND A FEW EMBEDDED THUNDERSTORMS CONTINUES TO MOVE ACROSS NORTHERN NEBRASKA. A BRIEF IMPACT FOR KVTN...WITH MVFR CONDITIONS...OTHERWISE THE AREA WILL SHIFT EAST AND EXIT OVER THE NEXT FEW HOURS. MEANWHILE MORE MOISTURE...COMPARED TO RECENT DAYS...WILL HELP TO ALLOW DEVELOPMENT OF THUNDERSTORMS ACROSS THE WEST THIS AFTERNOON...WHICH WILL PROPAGATE EASTWARD THIS EVENING. HAVE INCLUDED THUNDERSTORMS IN BOTH THE KLBF AND KVTN TAF...HOWEVER HIGHER CONFIDENCE IS FOR KVTN. ALL ACTIVITY WILL PUSH EAST OF THE TERMINALS OVERNIGHT...AS THE UPPER LEVEL WAVE PUSHES EAST...RESULTING IN DECREASING CLOUDS AND LIGHT WINDS...UNDER 10 KTS. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...CDC LONG TERM...TAYLOR AVIATION...MASEK
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
623 AM CDT SUN JUL 7 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 311 AM CDT SUN JUL 7 2013 IF MOISTURE CAN REMAIN IN PLACE THIS MORNING THEN ANOTHER ROUND OF THUNDERSTORMS COULD DEVELOP THIS AFTERNOON AND TONIGHT. THE DISTURBANCE AND ONGOING STORM ACTIVITY ACROSS WESTERN NEB SHOULD EXIT THE FCST AREA TO EAST BY 20Z. THIS IMPLIES THAT THE STORMS WEAKEN AND FALL APART AS THEY MOVE EAST AS INDICATED BY THE HRRR. DEEP EASTERLIES SHOULD CONTINUE TODAY AS INDICATED BY THE VWP AT KUDX AND THIS WOULD SUPPORT DESTABILIZATION ACROSS WESTERN NEB LATE THIS MORNING THROUGH THIS EVENING WHICH IN TURN WOULD PROPAGATE EAST THROUGH THE FCST AREA. THE FCST MIGHT BE AMBITIOUS WITH THE 40 POPS BUT THIS IS A MARK DOWN FROM A 5 MODEL BLEND OF THE ECM...GFS...SREF...NAM AND GEMREG. WATER VAPOR SUGGESTS ANOTHER DISTURBANCE ACROSS WRN WY AND NRN UT WHICH COULD COME ACROSS THIS AFTERNOON ON THE HEALS OF THE ONGOING DISTURBANCE. MODEST DEEP LAYER SHEAR UP TO 250 MB WOULD PERHAPS SUPPORT ISOLATED SEVERE STORMS WHICH WOULD PROBABLY PULSE SEVERE FROM TIME TO TIME THIS AFTERNOON AND THIS EVENING. THE WEAKNESS IN THE LOW LEVEL WINDS SUGGESTS THIS BEHAVIOR. SPC SUGGESTED A WEAKLY ORGANIZED MCS MIGHT DEVELOP AND THIS CERTAINLY APPEARS IN LINE WITH THE 21Z OUTPUT OF THE 06Z HRRR SHOWING A FAIRLY ORGANIZED LINE OF STORMS FROM KOGA TO KVTN. HIGHS IN THE UPPER 80S TO MID 90S ARE EXPECTED TODAY. THE MODELS HAVE COME IN A FEW DEGREES COOLER FOR HIGHS TODAY VERSUS SATURDAY. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 311 AM CDT SUN JUL 7 2013 ACTIVE FIRST HALF OF THE WEEK EXPECTED...AS THE AREA REMAINS ON THE NORTHERN SIDE OF LARGE RIDGE OF UPPER HIGH PRESSURE CENTERED ACROSS THE FOUR CORNERS REGION. WINDS ALOFT...MOISTURE...AND INSTABILITY WILL BE FAVORABLE FOR TSTMS UNTIL THE RIDGE BEGINS TO BUILD NORTH OVER THE AREA BY WEEKS END. TEMPERATURES ALOFT WILL WARM THEN AS WELL AS A DECREASE IN WINDS ALOFT...CONDITIONS LESS FAVORABLE FOR TSTM DEVELOPMENT. A STATIONARY FRONT WILL OSCILLATE NORTH AND SOUTH THE FIRST HALF OF THE WEEK...AND WILL BE A FOCUS FOR STORM DEVELOPMENT. OTHER STORMS MAY FORM OFF THE HIGHER TERRAIN TO OUR WEST AND MOVE EAST INTO THE AREA DURING THE EVENING HOURS. PWATS WILL BE RATHER HIGH...WITH PLENTY OF LOW LEVEL MOISTURE IN PLACE TOO...SO SOME DECENT RAINFALL TOTALS ARE POSSIBLE. TEMPERATURES WILL BE WARM...AND THEN TURNING HOT BY WEEKS END AS THE RIDGE BUILDS NORTH OVER THE AREA. HIGHS IN THE UPPER 80S TO MID 90S WILL START THE WEEK...WITH MID 90S TO AROUND 100 TO FINISH THE WEEK. DEPENDING ON DEW POINTS...WHICH CURRENTLY LOOK TO REMAIN HIGH EAST OF HIGHWAY 83 AS THE HEAT BUILDS IN BY THE END OF THE WEEK...WE COULD BE FLIRTING WITH HEAT ADVISORY CONDITIONS. WILL CONTINUE TO MONITOR. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 620 AM CDT SUN JUL 7 2013 VFR IS EXPECTED THROUGH 18Z MOST AREAS. THEREAFTER...THE MODEL CONSENSUS SUGGESTS SCATTERED THUNDERSTORMS WILL DEVELOP ACROSS AN INCREASINGLY LARGER PORTION OF THE FCST AREA AND SPREAD EAST THROUGH SUNDAY NIGHT. STORM ACTIVITY ACROSS NORTHWEST NEBRASKA SHOULD CONTINUE THIS MORNING WITH VFR ELSEWHERE. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...CDC LONG TERM...TAYLOR AVIATION...CDC
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
332 AM CDT SUN JUL 7 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 311 AM CDT SUN JUL 7 2013 IF MOISTURE CAN REMAIN IN PLACE THIS MORNING THEN ANOTHER ROUND OF THUNDERSTORMS COULD DEVELOP THIS AFTERNOON AND TONIGHT. THE DISTURBANCE AND ONGOING STORM ACTIVITY ACROSS WESTERN NEB SHOULD EXIT THE FCST AREA TO EAST BY 20Z. THIS IMPLIES THAT THE STORMS WEAKEN AND FALL APART AS THEY MOVE EAST AS INDICATED BY THE HRRR. DEEP EASTERLIES SHOULD CONTINUE TODAY AS INDICATED BY THE VWP AT KUDX AND THIS WOULD SUPPORT DESTABILIZATION ACROSS WESTERN NEB LATE THIS MORNING THROUGH THIS EVENING WHICH IN TURN WOULD PROPAGATE EAST THROUGH THE FCST AREA. THE FCST MIGHT BE AMBITIOUS WITH THE 40 POPS BUT THIS IS A MARK DOWN FROM A 5 MODEL BLEND OF THE ECM...GFS...SREF...NAM AND GEMREG. WATER VAPOR SUGGESTS ANOTHER DISTURBANCE ACROSS WRN WY AND NRN UT WHICH COULD COME ACROSS THIS AFTERNOON ON THE HEALS OF THE ONGOING DISTURBANCE. MODEST DEEP LAYER SHEAR UP TO 250 MB WOULD PERHAPS SUPPORT ISOLATED SEVERE STORMS WHICH WOULD PROBABLY PULSE SEVERE FROM TIME TO TIME THIS AFTERNOON AND THIS EVENING. THE WEAKNESS IN THE LOW LEVEL WINDS SUGGESTS THIS BEHAVIOR. SPC SUGGESTED A WEAKLY ORGANIZED MCS MIGHT DEVELOP AND THIS CERTAINLY APPEARS IN LINE WITH THE 21Z OUTPUT OF THE 06Z HRRR SHOWING A FAIRLY ORGANIZED LINE OF STORMS FROM KOGA TO KVTN. HIGHS IN THE UPPER 80S TO MID 90S ARE EXPECTED TODAY. THE MODELS HAVE COME IN A FEW DEGREES COOLER FOR HIGHS TODAY VERSUS SATURDAY. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 311 AM CDT SUN JUL 7 2013 ACTIVE FIRST HALF OF THE WEEK EXPECTED...AS THE AREA REMAINS ON THE NORTHERN SIDE OF LARGE RIDGE OF UPPER HIGH PRESSURE CENTERED ACROSS THE FOUR CORNERS REGION. WINDS ALOFT...MOISTURE...AND INSTABILITY WILL BE FAVORABLE FOR TSTMS UNTIL THE RIDGE BEGINS TO BUILD NORTH OVER THE AREA BY WEEKS END. TEMPERATURES ALOFT WILL WARM THEN AS WELL AS A DECREASE IN WINDS ALOFT...CONDITIONS LESS FAVORABLE FOR TSTM DEVELOPMENT. A STATIONARY FRONT WILL OSCILLATE NORTH AND SOUTH THE FIRST HALF OF THE WEEK...AND WILL BE A FOCUS FOR STORM DEVELOPMENT. OTHER STORMS MAY FORM OFF THE HIGHER TERRAIN TO OUR WEST AND MOVE EAST INTO THE AREA DURING THE EVENING HOURS. PWATS WILL BE RATHER HIGH...WITH PLENTY OF LOW LEVEL MOISTURE IN PLACE TOO...SO SOME DECENT RAINFALL TOTALS ARE POSSIBLE. TEMPERATURES WILL BE WARM...AND THEN TURNING HOT BY WEEKS END AS THE RIDGE BUILDS NORTH OVER THE AREA. HIGHS IN THE UPPER 80S TO MID 90S WILL START THE WEEK...WITH MID 90S TO AROUND 100 TO FINISH THE WEEK. DEPENDING ON DEW POINTS...WHICH CURRENTLY LOOK TO REMAIN HIGH EAST OF HIGHWAY 83 AS THE HEAT BUILDS IN BY THE END OF THE WEEK...WE COULD BE FLIRTING WITH HEAT ADVISORY CONDITIONS. WILL CONTINUE TO MONITOR. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 1226 AM CDT SUN JUL 7 2013 CLUSTER OF TSRA MOVING INTO PORTIONS OF NORTH CENTRAL NEBRASKA CONTINUE TO MOVE EAST AND SEEM TO BE MAINTAINING STRENGTH...UNLIKE TSRA EARLIER IN THE EVENING AS THEY ENCOUNTERED LESS FAVORABLE MID LEVEL INSTABILITY. INSTABILITY MAY BE SLIGHTLY BETTER NOW BASED ON MESOANALYSIS OF MID LEVEL LAPSE RATES. AT THIS TIME HAVE MENTIONED VCTS FOR KVTN AFTER 08Z ASSUMING THEY HOLD TOGETHER. OTHERWISE VFR CONDITIONS FOR THE PERIOD...HOWEVER TSRA CHANCES INCREASE AGAIN SUNDAY AFTER ABOUT 20Z WITH A BOUNDARY IN PLACE ACROSS THE SOUTHERN PORTION OF THE FCST AREA. INCREASING LOW LEVEL MOISTURE NORTH OF THE BOUNDARY LEADING TO A BETTER SHEAR/CAPE BALANCE SHOULD ALLOW BETTER COVERAGE OF STORMS TO AFFECT TAF SITES DURING THE FAVORED DIURNAL PERIOD FOR TSRA. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...CDC LONG TERM...TAYLOR AVIATION...JWS
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1145 PM CDT SAT JUL 6 2013 .DISCUSSION... PROBABLY NOT MUCH OF A CHANCE OF ANY PRECIPITATION OVERNIGHT AS WHATEVER REMAINS OF A WEAK UPPER LEVEL DISTURBANCE THAT WAS MOVING THROUGH CENTRAL NEBRASKA CONTINUES TO WASH OUT OVERNIGHT AS THE SURFACE FRONT REMAINS TO OUR WEST. && .AVIATION...06Z TAFS FOR KOMA...KLNK AND KOFK. VFR CONDITIONS THROUGH THE PERIOD WITH SOUTHEAST WINDS LESS THAN 10 KNOTS GENERALLY...WITH WINDS BECOMING SOUTHWEST BY 15Z. A FRONTAL BOUNDARY WILL BE MOVING INTO THE AREA SUNDAY MORNING...WHICH SHOULD BRING A SURFACE WIND SHIFT TO THE NORTHEAST AT KOFK BY 15Z. DEWALD PREV DISCUSSION... /ISSUED 331 PM CDT SAT JUL 6 2013/ DISCUSSION... OFF-AND-ON THUNDERSTORM CHANCES OVER THE NEXT SEVERAL DAYS ARE THE MAIN FORECAST CONCERNS. MORNING UPPER AIR CHARTS SHOWED HIGH PRESSURE IN THE SOUTHWEST STATES AND OFF THE ATLANTIC COAST WITH A WEAK LOW IN THE MIDDLE MOVING INTO THE OHIO VALLEY REGION. FAST WESTERLY FLOW COVERED THE NORTHERN TIER OF THE CONUS. OUR AREA REMAINED IN THE TRANSITION ZONE OF HIGHER HEIGHTS TO THE SOUTH AND FAST FLOW TO THE NORTH. AT THE SURFACE...A WIND SHIFT LINE WAS NOTED IN CENTRAL SOUTH DAKOTA AND WESTERN NEBRASKA...TIED TO A SHORTWAVE EXTENDING FROM THE NORTHERN PLAINS INTO NEBRASKA. AND A COLD FRONT WAS PUSHING INTO THE WESTERN DAKOTAS. LIGHT SHOWERS OR SPRINKLES THAT MOVED ACROSS EASTERN NEBRASKA THIS MORNING HAVE LEFT OUR AREA CAPPED TO CONVECTION SO FAR THIS AFTERNOON. RAP SOUNDINGS SUGGEST SURFACE-BASED CAPES WERE TOPPING 1000 J/KG...BUT INHIBITION WAS STILL ROBUST. BUT WITH TEMPERATURES WARMING A FEW MORE DEGREES LATE IN THE DAY...COULD SEE AN ISOLATED SHOWER OR STORM POP UP THIS EVENING...PROBABLY IN WESTERN IOWA. THEN LATER TONIGHT...WIND SHIFT LINE WILL SETTLE SOUTHEAST INTO OUR AREA AS SHORTWAVE MOVES OFF TO THE EAST. INSTABILITY WAS STRONG IN CENTRAL/WESTERN SOUTH DAKOTA NEAR/AHEAD OF WIND SHIFT...SO AM EXPECTING STORMS TO FIRE THERE LATE THIS AFTERNOON OR EVENING. THIS ACTIVITY SHOULD PUSH OFF TO THE EAST BUT COULD SKIRT OUR NORTHERN CWA. OTHERWISE MORE GENERAL THUNDER CHANCES ARE POSSIBLE WITH WIND SHIFT LINE AS IT MOVES INTO EASTERN NEBRASKA AFTER MIDNIGHT. SURFACE BOUNDARY WILL REMAIN IN OUR AREA DURING THE DAY SUNDAY. NOT MUCH NOTED IN MID LEVEL FLOW TO KICK UP CONVECTION ALONG THE FRONT...SO WILL HAVE TO WAIT UNTIL LATE AFTERNOON WHEN INSTABILITY IS MAXIMIZED. THEN FRONT/WIND SHIFT SHOULD BE OVER NORTHEAST NEBRASKA...SO HAVE MAINTAINED A SMALL CHANCE FOR THUNDERSTORMS THERE. BETTER CHANCES FOR STORMS WILL COME SUNDAY NIGHT INTO MONDAY AS ANOTHER SHORTWAVE MOVES INTO THE PLAINS. MEANWHILE FRONTAL BOUNDARY WILL SETTLE SOUTH SUNDAY NIGHT...THE LIFT BACK NORTH ON MONDAY. COMBINATION OF TEMPERATURES CLIMBING INTO THE 90S AND COOLING TEMPERATURES ALOFT WITH SHORTWAVE WILL PRODUCE CAPES APPROACHING 3000 J/KG WITH 30KT OF 0-6KM BULK SHEAR MONDAY AFTERNOON. SO WILL CONTINUE OUR SMALL CHANCES FOR STORMS SUNDAY NIGHT AS BOUNDARY SETTLES SOUTH...AND HIGHER CHANCES MONDAY AFTERNOON IN THE NORTH WHERE BOUNDARY/INSTABILITY WILL BE MAXIMIZED. SOME SEVERE STORMS ARE POSSIBLE GIVEN INSTABILITY/SHEAR. STORMS CHANCES SHOULD CONTINUE MONDAY NIGHT INTO TUESDAY AS FRONTAL BOUNDARY REMAINS IN OUR AREA...REINFORCED BEHIND EXITING SHORTWAVE. INSTABILITY WILL AGAIN APPROACH 3000 J/KG ALONG BOUNDARY TUESDAY AFTERNOON...WITH A TAD GREATER SHEAR. SO AGAIN SEVERE IS POSSIBLE TUESDAY AFTERNOON. FRONT IS FORECAST TO SETTLE SOUTH OF OUR AREA ON WEDNESDAY...SO WILL KEEP WEDNESDAY AND THURSDAY DRY. UPPER RIDGE BEGINS TO BUILD INTO OUR AREA FRIDAY AND SATURDAY SIGNALING A RETURN TO WARMER TEMPERATURES. AS RIDGE BUILDS...WARM ADVECTION REGIME ON FRIDAY COULD SPARK STORMS...BUT DRY AFTER THAT AS MID LEVEL TEMPS WARM. TEMPERATURES INTO MONDAY AND TUESDAY WILL EASILY REACH THE 90S...BUT COULD HOLD IN THE 80S WHERE STORMS/CLOUDS LINGER. A LITTLE COOLER WEDNESDAY AND THURSDAY WITH HIGHS IN THE 80S...BUT A RETURN TO 90S LOOK LIKELY FRIDAY AND SATURDAY. DERGAN && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
435 PM EDT SUN JUL 7 2013 .SYNOPSIS... A WARM AND HUMID AIRMASS WILL PERSIST ACROSS THE REGION THROUGH MUCH OF THE WEEK WITH NEAR DAILY CHANCES OF SHOWERS AND THUNDERSTORMS EXPECTED. THE HIGHEST CONCENTRATION OF SHOWERS AND STORMS WILL OCCUR ON MONDAY AND AGAIN ON WEDNESDAY WHEN LOCALLY HEAVY RAINFALL IS POSSIBLE. TEMPERATURES WILL REMAIN ON THE WARM SIDE...WITH HIGHS IN THE 80S AND OVERNIGHT LOWS GENERALLY IN THE 60S. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... AS OF 435 PM EDT SUNDAY...A WARM AND HUMID NIGHT EXPECTED ACROSS THE AREA AS DEEPER SUBTROPICAL FLOW HAS PUSHED BACK NORTH AND EAST INTO THE AREA AS EXPECTED. SCATTERED SHOWERS ALSO EXPECTED ON AND OFF THROUGH THE EVENING AND NIGHTTIME HOURS AS HI-RES MODELS AND THIS AFTERNOON`S RAP ANALYSIS SHOWING A WEAK SHORTWAVE MOVING THROUGH THE FLOW ACROSS OUR AREA. MID-LEVEL MOISTURE CONVERGENCE ALSO EVIDENT AS WEAK SURFACE FRONT SAGS SOUTH TO NEAR THE INTL BORDER OVERNIGHT AND STALLS. WITH SUCH WEAK FEATURES QUITE DIFFICULT TO TIME AREAL PLACEMENT AND INTENSITY OF PCPN...BUT PER LATEST LAPS/RUC PROGS WILL ADVERTISE HIGH CHANCE POPS AND CONFINE HIGHER THREAT OF THUNDER AND LOCALLY HEAVY RAINFALL TO OUR SOUTHERN COUNTIES WHERE BEST MLCAPE PROFILES EXIST. AGAIN...A MUGGY NIGHT EXPECTED AS SURFACE DEWPOINTS HOLD IN THE 60S TO AROUND 70. WINDS LIGHT. && .SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/... AS OF 435 PM EDT SUNDAY...BY MONDAY STILL LOOKING AT SCATTERED TO WIDESPREAD SHOWERS AND THUNDER ACROSS MUCH OF THE AREA WITH WARM AND MOIST AIRMASS IN PLACE ON THE WESTERN PERIPHERY OF STRONG BERMUDA HIGH PRESSURE. WE`LL ALSO HAVE SOME ADDED IMPETUS FROM A WEAKENING MID-LEVEL SHORTWAVE TROUGH LIFTING OUT OF THE LOWER GREAT LAKES/OHIO VALLEY STATES THROUGH THE DAY. THIS COMBINED WITH LIGHTLY VEERED PBL FLOW...LOWER NCAPE AND DEEP WCD VALUES IN EXCESS OF 11 KFT ALL SUPPORT CONTINUED MENTION OF LOCALLY HEAVY RAINFALL IN THE MORE ROBUST CELLS WHERE EFFICIENT PRECIPITATION LOADING WILL BE LIKELY. WHILE I CAN`T COMPLETELY RULE OUT AN ISOLATED SEVERE CELL...WITH SUCH HIGH WBZ VALUES I`M REALLY NOT EXPECTING ANYTHING OTHER THAN SOME BRIEF GUSTY WINDS AND POSSIBLE SMALL HAIL IN THE STRONGER CORES. HIGHS ON THE SEASONABLY WARM SIDE...76 TO 84 OR CLOSE TO BLENDED BIAS-CORRECTED GUIDANCE. EVENING SHOWERS AND STORMS THEN SLOWLY WANE IN AREAL COVERAGE AND INTENSITY AS WE PROGRESS INTO MONDAY NIGHT AS SHORTWAVE EXITS EAST AND WEAK RIDGING ALONG WITH LAYER OF DRIER MID-LEVEL AIR ADVECTS INTO THE REGION. NO AIRMASS CHANGE...BUT ENOUGH DRYING SUCH THAT MANY AREAS SHOULD TREND DRY BY TUESDAY MORNING. LOWS MAINLY IN THE 60S. THEN MORE UNCERTAINTY AS WE HEAD INTO TUESDAY. FEELING IS TUESDAY SHOULD BE MORE DRY THAN WET GIVEN MID-LEVEL DRY AIR AND WEAK SUBSIDENCE ADVECTING ACROSS THE REGION...BUT EVIDENCE THAT SOME SORT OF LOWER LEVEL MOISTURE BOUNDARY MAY LINGER ACROSS OUR EASTERN COUNTIES. ECMWF MORE ROBUST WITH CHANCES PCPN THAN OTHER SHORT TERM MODELS...BUT WILL DOWNPLAY AT THIS POINT OFFERING JUST SLIGHT TO LOWER CHANCE POPS THROUGH THE DAY AND MAINLY ACROSS VT WHERE SOME WIDELY SCATTERED ACTIVITY MAY OCCUR. HIGHS IN THE LOWER TO MID 80S. BY TUESDAY NIGHT WARM AND HUMID CONDITIONS CONTINUE BUT MAINLY DRY WITH LOSS OF INSOLATION. LOWS TO HOLD ON THE MILD SIDE AND MAINLY IN THE 60S. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... AS OF 400 PM EDT SUNDAY...ACTIVE WEATHER DAY EXPECTED WEDS/THURS AS POTENT TROF DEVELOPS ACRS THE NORTHERN GREAT LAKES AND SFC COLD FRNT MOVES ACRS OUR CWA. THIS FRNT WL INTERACT WITH MODEST INSTABILITY WITH LIS AROUND -4C AND CAPE VALUES BTWN 1500 TO 2000 J/KG. ALSO...NOTED A RIBBON OF ENHANCED MID LVL WINDS...CREATING DEEP LAYER SHEAR VALUES BTWN 30 AND 40 KNOTS...ESPECIALLY ACRS OUR NORTHERN CWA ON WEDS AFTN. THE AREAL COVERAGE/INTENSITY OF STORMS WL HIGHLY DEPEND UPON AMOUNT OF INSTABILITY/CLRING AND EXACT TRACK OF S/W ENERGY. GIVEN...THE GOOD AGREEMENT IN MODELS WITH SYNOPTIC FEATURES WL CONT TO MENTION HIGH CHC/LOW LIKELY POPS WEDS INTO WEDS NIGHT...STILL A MINOR TIMING DIFFERENCE BTWN THE FASTER GFS AND SLOWER ECMWF. WEAK SUBSIDENCE AND HIGH PRES TRIES TO BUILD ACRS OUR CWA LATE THURS INTO FRIDAY...WITH A BRIEF DRY SPELL POSSIBLE. LOTS OF UNCERTAINTY ASSOCIATED WITH NEXT SYSTEM FRIDAY INTO NEXT WEEKEND...WITH GFS SHOWING MID/UPPER CLOSED CIRCULATION ACRS THE GREAT LAKES RETROGRADING SW TWD TEXAS BY SUNDAY...WHILE THE ECMWF SPLITS THE SYSTEM INTO TWO DISTINCT CLOSED CIRCULATIONS WITH GREATER IMPACT ACRS OUR FA. GIVEN THE UNCERTAINTY IN THE EVOLUTION OF THIS COMPLEX SYNOPTIC PATTERN...WL MENTION CHC POPS NEXT WEEKEND. IF THE ULVL PATTERN VERIFIES ON THE ECMWF AND DEEP TROPICAL MOISTURE IS ADVECTED BACK INTO THE NE CONUS...HYDRO WL NEED TO BE WATCHED CLOSELY...FOR THE POTENTIAL FOR HEAVY RAINFALL. PROGGED 85H TEMPS AHEAD OF BOUNDARY RANGE BTWN 14-16C ON WEDS/THURS...BEFORE COOLING BACK BTWN 10-12C ON FRIDAY...SUPPORTING HIGHS MID/UPPER 80S MID WEEK TO M70S TO L80S BY NEXT FRIDAY. LOWS WL BE MAINLY IN THE U50S MTNS TO M60S VALLEYS. && .AVIATION /21Z SUNDAY THROUGH FRIDAY/... THROUGH 18Z MONDAY...CRNT RADAR SHOWS RAIN SHOWERS INCREASING IN AREAL COVERAGE/INTENSITY ACRS NORTHERN NY AND INTO THE WESTERN CPV ATTM. EXPECT THIS ACTIVITY TO IMPACT OUR TAF SITES BTWN 18Z-22Z THIS AFTN WITH A BRIEF SHOWER AND POSSIBLE MVFR CONDITIONS IN THE HEAVIER SHOWER. THE POTENTIAL FOR ADDITIONAL SHOWERS WITH AN EMBEDDED STORM WL CONT OVERNIGHT INTO MONDAY...AS SEVERAL EMBEDDED S/W`S INTERACT WITH SFC INSTABILITY. DIFFICULT TO PIN POINT EXACT TIMING AND LOCATION OF STORMS...THEREFORE USED VCSH THRU MOST OF THE NIGHT. ALSO...GIVEN THE INCREASED SFC DWPTS AND BL MOISTURE...AREAS OF HZ/BR WL BE POSSIBLE ESPECIALLY AT SITES THAT RECIEVE RAIN THIS AFTN AND AT KMSS. SOUTH TO SOUTHWEST WINDS AT 4 TO 8 KNOTS THIS AFTN...WL BECM LIGHT TRRN DRIVEN TONIGHT. OUTLOOK 18Z MONDAY THROUGH THURSDAY...SCATTERED SHOWERS AND THUNDERSTORMS WL BE POSSIBLE MONDAY AND AGAIN ON WEDS/THURS. THIS ACTIVITY WL HAVE THE POTENTIAL TO PRODUCE BRIEF PERIODS OF MVFR CONDITIONS ALONG WITH LOCALIZED GUSTY WINDS IN AND NEAR STORMS. ALSO...LOOK FOR SOME BR/FOG TO DEVELOP IF SKIES CAN CLR...ESPECIALLY AT MPV/SLK BTWN 07-11Z...WITH GENERALLY SOUTH TO SOUTHWEST WINDS THRU THE PERIOD. && .HYDROLOGY... AS OF 435 PM EDT SUNDAY... LOCALLY HEAVY RAINFALL WILL REMAIN POSSIBLE ACROSS THE SOUTHERN PORTIONS OF THE FORECAST AREA THIS EVENING...AND ACROSS THE ENTIRE AREA ON MONDAY. WHILE WIDESPREAD OR ORGANIZED AREAS OF FLASH FLOODING ARE NOT EXPECTED...WCD VALUES WILL REMAIN QUITE HIGH ALONG WITH HIGH COLUMNAR MOISTURE PROFILES. THUS POINT TOTALS IN EXCESS OF ONE INCH IN AN HOUR OR LESS WILL BE POSSIBLE...WHICH CHOULD LEAD TO LOCALIZED HYDROLOGICAL CONCERNS...ESPECIALLY ON MONDAY WHEN BOUNDARY LAYER FLOW WILL BE QUITE LIGHT BELOW 850 MB. && .EQUIPMENT... AS OF 415 AM EDT SUNDAY...THE KTYX RADAR IS DOWN UNTIL FURTHER NOTICE. TECHS HAVE ORDERED PARTS...WHICH SHOULD ARRIVE ON MONDAY AND THE RADAR SHOULD BE RETURNED TO SERVICE BY TUESDAY. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...NONE. NY...NONE. && $$ SYNOPSIS...JMG NEAR TERM...JMG SHORT TERM...JMG LONG TERM...TABER AVIATION...TABER HYDROLOGY...JMG EQUIPMENT...BTV
AREA FORECAST DISCUSSION
NWS BUFFALO NY
332 PM EDT SUN JUL 7 2013 .SYNOPSIS... A PERSISTENT TROUGH OF LOW PRESSURE WILL GRADUALLY SLIDE EASTWARD ACROSS THE REGION EARLY NEXT WEEK. THIS WILL RESULT IN CONTINUED UNSETTLED WEATHER THROUGH MID-WEEK BEFORE DRIER AIR FINALLY ARRIVES BY THE END OF THE WEEK AS HIGH PRESSURE BUILDS INTO THE GREAT LAKES. && .NEAR TERM /THROUGH MONDAY/... AS OF MID-AFTERNOON...RADAR SHOWS MOST OF WESTERN NEW YORK IS SHOWER-FREE...WITH JUST A FEW SHOWERS STARTING TO DEVELOP ACROSS WESTERN PORTIONS OF THE SOUTHERN TIER. MEANWHILE...THE MOST NOTEWORTHY FEATURE IS CONVECTION DEVELOPING ACROSS CENTRAL PENNSYLVANIA. BOTH THE GFS/HRRR HANDLED AN INITIAL WAVE OF CONVECTION EARLY THIS MORNING...AND IT APPEARS THESE MODELS ALSO HAVE A GOOD HANDLE ON THE NEXT WAVE AS WELL. USING THIS GUIDANCE...EXPECT THAT ORGANIZED CONVECTION WILL TRACK TO OUR SOUTHEAST THROUGH EARLY EVENING. THIS LEAVES ONLY SUBTLE SURFACE BOUNDARIES TO PROVIDE THE FOCUS NEEDED FOR SHOWERS AND THUNDERSTORMS LATE THIS AFTERNOON. THERE WILL BE LAKE BREEZES BOTH EAST OF LAKE ERIE...AND SOUTH AND EAST OF THE EASTERN HALF OF LAKE ONTARIO. IN EACH CASE...EXPECT ANY SHOWERS TO BE SCATTERED IN NATURE...WITH A FEW THUNDERSTORMS ALSO POSSIBLE. NE OF LAKE ONTARIO AND LAKE ERIE...EXPECT THE WELL DEVELOPED SW FLOW TO STABILIZE THE BOUNDARY LAYER...AND KEEP THE BUFFALO METRO AREA DRY THIS AFTERNOON...EVEN IF HIGH CLOUDS FROM UPSTREAM LIMIT SUNSHINE. FOR THIS EVENING...CONVECTION ACROSS PENNSYLVANIA SHOULD REMAIN TO THE SOUTH...WITH MOST OF THE DIURNALLY DRIVEN SHOWERS LIKELY TO TAPER OFF. HOWEVER...THERE IS SOME INDICATION THAT SHOWERS MAY DEVELOP ACROSS CENTRAL NEW YORK IF AN OUTFLOW FROM THE CONVECTION TO THE SOUTH INTERACTS WITH LINGERING INSTABILITY IN THE REGION. THIS AREA WILL ALSO BE UNDERNEATH A DIFLUENT FLOW ALOFT AHEAD OF AN APPROACHING UPPER LOW...WHICH WOULD ENHANCE THE CONVECTIVE POTENTIAL. THIS POSSIBILITY IS SHOWN BY THE HRRR AND 12Z RGEM...AND TO A LESSER EXTENT 12Z GFS/NAM. IT IS MOST LIKELY TO STAY SE OF OUR CWA...BUT MAY REACH INTO THE FINGER LAKES REGION. THIS FEATURE BEARS WATCHING GIVING THE CONTINUED MOIST ENVIRONMENT WITH PRECIPTABLE WATER VALUES STILL IN THE 1.75 INCH RANGE. SLOW MOVING THUNDERSTORMS COULD PRODUCE LOCALLY HEAVY RAINFALL AND FLOODING. OTHERWISE...AN UPPER LEVEL TROF IS FORECAST TO SLOWLY LIFT ACROSS WESTERN PENNSYLVANIA OVERNIGHT. THIS WILL BRING A CHANCE OF MORE GENERAL SHOWER ACTIVITY...HOWEVER IT SHOULD BE SOMEWHAT SPOTTY IN NATURE. AS HAS BEEN THE CASE...SOME PATCHY FOG IS POSSIBLE IN THE SOUTHERN TIER VALLEYS...AND EAST OF LAKE ONTARIO. LOWS SHOULD RANGE FROM THE MID 60S TO AROUND 70. ON MONDAY...THE CLOSED UPPER LEVEL LOW WILL GRADUALLY OPEN AS IT SLIDES TO THE EAST. THIS FEATURE WILL RESULT IN A CONTINUED THREAT FOR SHOWERS DURING THE DAY MONDAY...AS DAYTIME INSTABILITY ENHANCES SHOWER ACTIVITY. SLIGHTLY COOLER TEMPERATURES ALOFT SHOULD ALLOW STORMS TO DEVELOP LIGHTNING A BIT MORE QUICKLY THAN THE PAST COUPLE DAYS. AS THE OPENING TROF EXITS TO THE EAST...EXPECT DRYING WITH THE SUBSTANCE ASSOCIATED WITH THE EXITING FEATURE. AS A RESULT...SHOWERS AND THUNDERSTORMS SHOULD TAPER OFF FROM WEST TO EAST DURING THE AFTERNOON HOURS. TEMPERATURES WILL BE A TAD COOLER...WITH HIGHS INT HE UPPER 70S TO LOWER 80S. IT WILL CONTINUE TO BE MOIST RESULTING IN CONTINUED MUGGY CONDITIONS. && .SHORT TERM /MONDAY NIGHT THROUGH THURSDAY NIGHT/... AS THE AXIS OF THE UPPER TROUGH WILL HAVE PASSED TO THE EAST OF THE FORECAST AREA...EXPECT A SHARP DROP OFF IN POPS FOR MONDAY NIGHT. WARM ADVECTION THROUGHOUT THE BOUNDARY LAYER WILL ARRIVE IN WESTERN AND SOUTHERN NY ON TUESDAY WITH INCREASING BUT STILL LOW CHANCE OF THUNDERSTORMS ACROSS THE SOUTHERN TIER...MAINLY DURING TUESDAY AFTERNOON. TEMPS MONDAY NIGHT WILL BE IN THE LOWER TO MID 60S ACROSS THE SOUTHERN TIER AND TUG HILL...AND MID 60S TO NEAR 70 FOR THE LAKE PLAINS AND URBAN AREAS. HIGHS ON TUESDAY WILL RISE A NOTCH TO THE LOWER TO MID 80S. A TROUGH MOVING ACROSS ONTARIO PROVINCE WILL SPAWN A SURFACE LOW OVER THE UPPER MID WEST ON TUESDAY TO SOUTH OF JAMES BAY ON WEDNESDAY. 35 TO 40 KNOT WINDS AT 850MB ACROSS THE CENTRAL GREAT LAKES WILL FORM A WARM FRONT ASSOCIATED WITH THE SURFACE LOW. INCREASING MOISTURE AHEAD OF THE WARM FRONT...PRECIPITABLE WATER RISING BACK TO NEAR 2 INCHES...AND ADDED LIFT IN THE VICINITY OF THE SHORT WAVE TROUGH WILL BRING A GOOD CHANCE FOR SHOWERS AND THUNDERSTORMS TUESDAY NIGHT AND WEDNESDAY. UNSETTLED WEATHER WILL CONTINUE WEDNESDAY NIGHT AS A COLD FRONT...TRAILING SOUTH OF LOW PRESSURE NEAR JAMES BAY...PUSHES EAST ACROSS THE STATE. TEMPS TUESDAY NIGHT WILL RANGE FROM THE MID 60S ACROSS THE SOUTHERN TIER AND TUG HILL...TO LOWER 70S FOR THE LAKE PLAINS AND URBAN AREAS. HIGHS ON WEDNESDAY WILL BE SIMILAR TO TUESDAY...LOWER TO MID 80S...EVEN WITH THICKER CLOUD AND OCCURRENCE OF PRECIP. DRIER AND MARGINALLY COOLER AIR WILL ARRIVE IN THE POSTFRONTAL AIRMASS ON THURSDAY WITH LOWER CHANCE POPS AND PARTIAL CLEARING. EXPECT HIGHS IN THE MID TO UPPER 70S ON THURSDAY AND LOWS THURSDAY NIGHT IN THE UPPER 50S TO LOWER 60S AS SKIES CLEAR FURTHER. && .LONG TERM /FRIDAY THROUGH SUNDAY/... THE UPPER TROUGH ACROSS ONTARIO WILL STALL AND DIG FARTHER SOUTH...DEVELOPING A CUTOFF LOW ACROSS THE EASTERN U.S. THIS LOW WILL DROP FARTHER TO THE SOUTH ON THE WEEKEND AND BLOCK THE WARMER AIR FROM THE NATION`S MIDSECTION...ALSO TAPPING INTO MOISTURE FROM THE WESTERN ATLANTIC. FRIDAY AND FRIDAY NIGHT SHOULD REMAIN DRY AND QUITE COOLER WITH HIGHS IN THE 70S AND LOWS IN THE UPPER 50S TO LOW 60S. HIGHER CHANCE FOR SHOWERS AND THUNDERSTORMS WILL ARRIVE DURING SATURDAY AND SUNDAY AS THE SOUTHEASTERLY LOW LEVEL FLOW FROM THE MID ATLANTIC INTERACTS WITH THE MID AND UPPER LEVEL TROUGH. HIGH TEMPS FOR THE WEEKEND WILL BE IN THE MID TO UPPER 70S ON SATURDAY AND THE UPPER 70S TO LOWER 80S ON SUNDAY. && .AVIATION /20Z SUNDAY THROUGH FRIDAY/... EXPECT MAINLY VFR CONDITIONS FOR THE REMAINDER OF THIS AFTERNOON...WITH LINGERING MVFR CIGS LIKELY TO LIFT AND SCATTER. THERE MAY BE A FEW SHOWERS AND THUNDERSTORMS...BUT EXPECT THE SW FLOW TO KEEP THESE OUT OF BUF/IAG/ART/ROC...WHICH TEND TO BE SHADOWED IN THIS FLOW. JHW MAY SEE A THUNDERSTORM THIS AFTERNOON...BUT CONFIDENCE IS RELATIVELY LOW GIVEN STORMS SHOULD BE QUITE SCATTERED. FOR TONIGHT...EXPECT MORE SCATTERED SHOWERS AS THE UPPER LOW MOVES CLOSER TO THE REGION. THERE WILL BE QUITE A BIT OF LOW LEVEL MOISTURE IN PLACE...BUT AS LONG AS WINDS PERSIST AND THE MID AND HIGH CLOUDS REMAIN...EXPECT CIGS TO REMAIN MAINLY IN THE VFR RANGE. THIS SAID...ANY PROLONGED CLEARING WOULD LIKELY RESULT IN LOW CLOUDS AND FOG...WITH THE BEST CHANCE FOR THIS AT JHW/ART. THERE WILL BE A CONTINUED THREAT FOR SHOWERS AND POSSIBLY A THUNDERSTORM ON MONDAY. EXPECT MAINLY VFR CONDITIONS EXCEPT IN STORMS WHERE HEAVY RAINS COULD LOWER VSBY TO 2SM OR LESS. OUTLOOK... MONDAY NIGHT THROUGH WEDNESDAY...MAINLY VFR WITH SCATTERED SHOWERS AND THUNDERSTORMS AND ASSOCIATED BRIEF MVFR/IFR CONDITIONS. THURSDAY AND FRIDAY...VFR. && .MARINE... SOUTHWEST WINDS HAVE INCREASED ON LAKE ERIE AND WESTERN LAKE ONTARIO...HOWEVER THE STRONGEST WINDS ARE ON LAND WHERE WINDS ALOFT CAN MIX MORE READILY. WEBCAMS AND OBS SHOW ONLY MODEST WAVES WITH NO WHITE CAPS ALONG THE NEARSHORES OF LAKE ERIE. THERE MAY BE A DECENT CHOP ON WESTERN LAKE ONTARIO...DUE TO SW GUSTS NEAR THE IMMEDIATE SHORELINE...BUT WAVES SHOULD REMAIN WELL BELOW 4 FT SINCE WINDS WILL DIMINISH OFFSHORE. LIGHT TO MODERATE SOUTHWEST WINDS WILL CONTINUE TONIGHT THROUGH MONDAY WITH CHOPPY WAVE ACTION AT TIMES ON BOTH LAKE...BUT CONDITIONS SHOULD REMAIN BELOW SMALL CRAFT CRITERIA. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...NONE. MARINE...NONE. && $$ SYNOPSIS...APFFEL NEAR TERM...APFFEL SHORT TERM...WCH LONG TERM...WCH AVIATION...APFFEL MARINE...APFFEL/WCH
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
158 PM EDT SUN JUL 7 2013 .SYNOPSIS... WARM AND HUMID CONDITIONS WILL PERSIST OVER THE REGION THROUGH MONDAY WITH SCATTERED SHOWERS AND THUNDERSTORMS, PRIMARILY DURING THE AFTERNOON. SINCE THE AIRMASS REMAINS VERY MOIST ANY THUNDERSTORMS MAY PRODUCE LOCALIZED HEAVY RAINFALL. THE UPPER LEVEL TROUGH WILL EXIT THE NORTHEASTERN UNITED STATES MONDAY NIGHT BRINGING A BRIEF END TO THE RAIN. && .NEAR TERM /THROUGH TONIGHT/... 845 AM UPDATE... EARLY MRNG MCS HAS MOVD EAST AND IS ENTERING WRN NEW ENGLAND...WITH FCST AREA UNDER PC SKIES. TDA`S SCENARIO IS NOT MUCH DIFFERENT FROM PREV DAYS. UPR LOW OVER INDIANA THIS MRNG WITH S/WV`S ROTATING NEWD FROM THE ERN OH VLY INTO THE NE U.S.. NXT S/WV IS OVER WRN WV WHICH WILL BE HEADING NEWD TWDS WRN NY LATE TDA. OTHER THAN THIS FEATURE...THERE IS NOT MUCH TO FOCUS CONVECTIVE DVLPMNT TDA OTHER THAN ANY MESO-BETA BNDRYS AND TRRN FEATURES. IN THE NEAR TERM WE LOWERED POPS INTO EARLY AFTN AND REMOVED ANY QPF BEFORE 18Z...THEN CHC POPS THIS AFTN FOR SCT SHRA/TSRA. WIND SHEAR TDA IS MARGINAL FOR ORGANIZED STORMS AND IS ACTUALLY LOWERING THIS MRNG INTO EARLY AFTN...BUT INCREASES TO MARGINALLLY SUPPORTIVE VALUES ACRS WRN ZONES LATE TDA WITH APRCH OF NXT S/WV. GIVEN MOIST CONDITIONS...LCL +RA WILL BE MAIN THREAT WITH ANY STORMS TDA. PREV BLO... 630 AM UPDATE... JUST DID ANOTHER MAJOR RE-WORK OF THE POPS GRIDS AS S/WV IS EXITING STAGE RIGHT AT THIS TIME, TAKING THE STORMS WITH IT IN THE NEXT HR. BASED ON LATEST RUC FCST AND CURRENT TRENDS NOT EXPECTING MUCH IN THE WAY OF SHOWERS TO GET IN HERE BFR 15Z AND ONLY SCTD, AT BEST, AFTER THAT TIME. 520 AM UPDATE... QUICK UPDATE TO UP POPS ACRS UPSTATE NY TO 50% FOR CLUSTER OF TSTMS MVG THRU NRN ZONES. ALSO UPPED QPF TO AROUND 0.25 INCHES BASIN-AVERAGE THRU 12Z THO LOCALLY HIGHER AMNTS MAY EXIST. 330 AM UPDATE... BERMUDA RIDGE CONTS TO SPIN OFF THE ATLANTIC COAST WITH PLENTIFUL MOISTURE BEING PUMPED INTO CWA FM GOM. UL TROF/LOW IS ON THE MV AS RIDGE IS WEAKENING. S/WV LOCATED ACRS OH/KY AREA WL APPCH THE FA THIS AFTN AND RESULT IN A GOOD CHC FOR SHRA/TSRA ACTIVITY. THUS WL GO WITH LKLY POPS ACRS WRN ZONES ARND 18Z OR SO THEN DIMINISHING AFT THAT AS WV PASSES OFF TO THE WEST AND MID-LVL LAPSE RATES WEAKEN. AS FOR SVR POTENTIAL, EXPECT ONLY A STRONG STORM OR TWO AS 0-6KM BULK SHEAR VALUES WEAKEN THRU THE DAY. ANY TSTM THAT CAN DVLP WL HV THE POTENTIAL TO PRODUCE TORRENTIAL DOWNPOURS AND LOCALIZED FLOODING AND THIS WL LKLY BE THE MAIN THREAT FOR THIS AFTN. H8 TEMPS TO ARND 17C TDA WL YIELD HIGHS IN THE M/U 80S SIMILAR TO YDA. FOR TONIGHT, UL LOW WL OPEN UP ACRS NRN OHIO BY 06Z AND BEGIN TO EJECT EAST WITH SCTD THUNDER RMNG ACRS THE REGION THRU 12Z MONDAY. EXPECTING OVRNGT MINS TO RMN UP IN THE U60S WITH DWPTS RMNG JUST A DEGREE OR TWO LOWER. && .SHORT TERM /MONDAY THROUGH WEDNESDAY/... 330 AM UPDATE... UPR TROF WL BE EJECTING OUT DRG THE DAY ON MONDAY WITH PW VALUES GRADUALLY DROPPING THRU THE AFTN. POTENTIAL EXISTS FOR LCLY HVYR RAINFALL THRU THE COURSE OF THE DAY WITH UL TROF INTERACTING WITH FRONTAL BNDRY ACRS THE NERN U.S. THIS, IN ADDITION TO SATURATED SOIL CONDS WL BRING A HEIGHTENED THREAT FOR FLOODING ON MONDAY. THUS, WL HIGHLIGHT THREAT IN THE HWO. PCPN SHUD GRADUALLY WIND DOWN MON NGT AS FLOW TRANSITIONS TO A MORE ZONAL FLOW ALOFT. DIURNAL CONVECTION WL ONCE AGAIN BE POSSIBLE TUE AFTN BFR TAPERING OFF TUE NGT, AHD OF NEXT H5 TROF HEADED IN FM THE WEST. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... MEDIUM RANGE MODELS ARE IN EXCELLENT AGREEMENT THROUGH THE EXTENDED PERIOD. WED NIGHT THROUGH THURSDAY, UPPER LEVEL TROF WILL DROP THROUGH THE GREAT LAKES AS SFC COLD FRONT PASSES THROUGH THE AREA LATE WED NIGHT THROUGH THURSDAY MORNING. WILL CONTINUE WITH LIKELY POPS INTO THURSDAY MORNING THEN DROP BACK TO DRY WEST AND JUST CHC EAST BY THURSDAY AFTERNOON. THURSDAY NIGHT THROUGH SUNDAY...UPPER LEVEL TROF CUTS OFF OVER THE REGION THEN RETROGRADES LATE IN THE PERIOD AS WESTERN ATLANTIC RIDGE BUILDS. AT THE SFC, HIGH PRES WILL BUILD OVER THE AREA AND DOMINATE OUR WEATHER THROUGH FRIDAY NIGHT WITH PRIMARILY DRY CONDITIONS. SATURDAY THROUGH SUNDAY, AN INCREASINGLY MOIST SOUTHEAST FLOW WILL DEVELOP LEADING TO HUMID CONDITIONS AND CHC POPS FOR CONVECTION. HIGHEST POPS WILL BE OVER THE EASTERN CWA IN AN AREA OF BETTER MOISTURE AND OROGRAPHIC LIFT. TEMPS THROUGH THE PERIOD WILL BE NEAR SEASONAL NORMS. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... A VERY COMPLEX FORECAST NEXT 24 HRS. UPPER LEVEL LOW IN THE OHIO VALLEY WILL TRACK NORTHEAST INTO CENTRAL PA BY MONDAY. FOR THIS AFTERNOON, SCATTERED CONVECTION IS EXPECTED ALONG THE LAKE PLAIN THEREFORE INCLUDED 4 HOUR TEMPS GROUP FOR MVFR RAIN SHOWERS AT KRME/KSYR. THUNDERSTORMS ARE ALSO A POSSIBILITY BUT NOT INCLUDED AT THIS TIME. FOR THE REMAINDER OF TAFS, WAVE IN SOUTHWEST PA MAY INITIATE CONVECTION LATE THIS AFTERNOON THROUGH EARLY EVENING. INCLUDED TEMPO GROUP FOR MVFR SHOWERS BUT AGAIN THUNDERSTORMS ARE A POSSIBILITY. FOR A WHILE THIS EVENING CONDITIONS WILL BE PRIMARILY VFR BUT MVFR STRATUS IS EXPECTED LATE TONIGHT AT ALL SITES AS DEEPER MOISTURE SETTLES BACK OVER THE AREA WITH UPPER LEVEL FEATURE. FOR MONDAY, JUST WENT WITH CATEGORICAL SHOWERS WITH MVFR CIGS AFTER 15Z. SOUTHWEST WINS AT 5-10 KNOTS BECOMING LIGHT OVERNIGHT THEN SOUTHWEST AGAIN ON MONDAY. .OUTLOOK... MONDAY NIGHT...MVFR RESTRICTIONS PSBL IN EARLY MRNG STRATUS/FOG. TUESDAY THROUGH TUESDAY NIGHT...PRIMARILY VFR. WEDNESDAY THROUGH THURSDAY...RESTRICTIONS IN SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS. THURSDAY NIGHT THROUGH FRIDAY...PRIMARILY VFR ALTHOUGH VALLEY FOG IS POSSIBLE. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...PVN NEAR TERM... SHORT TERM...PVN LONG TERM...RRM AVIATION...RRM
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1206 PM EDT SUN JUL 7 2013 .SYNOPSIS... WARM AND HUMID CONDITIONS WILL PERSIST OVER THE REGION THROUGH MONDAY WITH SCATTERED SHOWERS AND THUNDERSTORMS, PRIMARILY DURING THE AFTERNOON. SINCE THE AIRMASS REMAINS VERY MOIST ANY THUNDERSTORMS MAY PRODUCE LOCALIZED HEAVY RAINFALL. THE UPPER LEVEL TROUGH WILL EXIT THE NORTHEASTERN UNITED STATES MONDAY NIGHT BRINGING A BRIEF END TO THE RAIN. && .NEAR TERM /THROUGH TONIGHT/... 845 AM UPDATE... EARLY MRNG MCS HAS MOVD EAST AND IS ENTERING WRN NEW ENGLAND...WITH FCST AREA UNDER PC SKIES. TDA`S SCENARIO IS NOT MUCH DIFFERENT FROM PREV DAYS. UPR LOW OVER INDIANA THIS MRNG WITH S/WV`S ROTATING NEWD FROM THE ERN OH VLY INTO THE NE U.S.. NXT S/WV IS OVER WRN WV WHICH WILL BE HEADING NEWD TWDS WRN NY LATE TDA. OTHER THAN THIS FEATURE...THERE IS NOT MUCH TO FOCUS CONVECTIVE DVLPMNT TDA OTHER THAN ANY MESO-BETA BNDRYS AND TRRN FEATURES. IN THE NEAR TERM WE LOWERED POPS INTO EARLY AFTN AND REMOVED ANY QPF BEFORE 18Z...THEN CHC POPS THIS AFTN FOR SCT SHRA/TSRA. WIND SHEAR TDA IS MARGINAL FOR ORGANIZED STORMS AND IS ACTUALLY LOWERING THIS MRNG INTO EARLY AFTN...BUT INCREASES TO MARGINALLLY SUPPORTIVE VALUES ACRS WRN ZONES LATE TDA WITH APRCH OF NXT S/WV. GIVEN MOIST CONDITIONS...LCL +RA WILL BE MAIN THREAT WITH ANY STORMS TDA. PREV BLO... 630 AM UPDATE... JUST DID ANOTHER MAJOR RE-WORK OF THE POPS GRIDS AS S/WV IS EXITING STAGE RIGHT AT THIS TIME, TAKING THE STORMS WITH IT IN THE NEXT HR. BASED ON LATEST RUC FCST AND CURRENT TRENDS NOT EXPECTING MUCH IN THE WAY OF SHOWERS TO GET IN HERE BFR 15Z AND ONLY SCTD, AT BEST, AFTER THAT TIME. 520 AM UPDATE... QUICK UPDATE TO UP POPS ACRS UPSTATE NY TO 50% FOR CLUSTER OF TSTMS MVG THRU NRN ZONES. ALSO UPPED QPF TO AROUND 0.25 INCHES BASIN-AVERAGE THRU 12Z THO LOCALLY HIGHER AMNTS MAY EXIST. 330 AM UPDATE... BERMUDA RIDGE CONTS TO SPIN OFF THE ATLANTIC COAST WITH PLENTIFUL MOISTURE BEING PUMPED INTO CWA FM GOM. UL TROF/LOW IS ON THE MV AS RIDGE IS WEAKENING. S/WV LOCATED ACRS OH/KY AREA WL APPCH THE FA THIS AFTN AND RESULT IN A GOOD CHC FOR SHRA/TSRA ACTIVITY. THUS WL GO WITH LKLY POPS ACRS WRN ZONES ARND 18Z OR SO THEN DIMINISHING AFT THAT AS WV PASSES OFF TO THE WEST AND MID-LVL LAPSE RATES WEAKEN. AS FOR SVR POTENTIAL, EXPECT ONLY A STRONG STORM OR TWO AS 0-6KM BULK SHEAR VALUES WEAKEN THRU THE DAY. ANY TSTM THAT CAN DVLP WL HV THE POTENTIAL TO PRODUCE TORRENTIAL DOWNPOURS AND LOCALIZED FLOODING AND THIS WL LKLY BE THE MAIN THREAT FOR THIS AFTN. H8 TEMPS TO ARND 17C TDA WL YIELD HIGHS IN THE M/U 80S SIMILAR TO YDA. FOR TONIGHT, UL LOW WL OPEN UP ACRS NRN OHIO BY 06Z AND BEGIN TO EJECT EAST WITH SCTD THUNDER RMNG ACRS THE REGION THRU 12Z MONDAY. EXPECTING OVRNGT MINS TO RMN UP IN THE U60S WITH DWPTS RMNG JUST A DEGREE OR TWO LOWER. && .SHORT TERM /MONDAY THROUGH WEDNESDAY/... 330 AM UPDATE... UPR TROF WL BE EJECTING OUT DRG THE DAY ON MONDAY WITH PW VALUES GRADUALLY DROPPING THRU THE AFTN. POTENTIAL EXISTS FOR LCLY HVYR RAINFALL THRU THE COURSE OF THE DAY WITH UL TROF INTERACTING WITH FRONTAL BNDRY ACRS THE NERN U.S. THIS, IN ADDITION TO SATURATED SOIL CONDS WL BRING A HEIGHTENED THREAT FOR FLOODING ON MONDAY. THUS, WL HIGHLIGHT THREAT IN THE HWO. PCPN SHUD GRADUALLY WIND DOWN MON NGT AS FLOW TRANSITIONS TO A MORE ZONAL FLOW ALOFT. DIURNAL CONVECTION WL ONCE AGAIN BE POSSIBLE TUE AFTN BFR TAPERING OFF TUE NGT, AHD OF NEXT H5 TROF HEADED IN FM THE WEST. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... MEDIUM RANGE MODELS ARE IN EXCELLENT AGREEMENT THROUGH THE EXTENDED PERIOD. WED NIGHT THROUGH THURSDAY, UPPER LEVEL TROF WILL DROP THROUGH THE GREAT LAKES AS SFC COLD FRONT PASSES THROUGH THE AREA LATE WED NIGHT THROUGH THURSDAY MORNING. WILL CONTINUE WITH LIKELY POPS INTO THURSDAY MORNING THEN DROP BACK TO DRY WEST AND JUST CHC EAST BY THURSDAY AFTERNOON. THURSDAY NIGHT THROUGH SUNDAY...UPPER LEVEL TROF CUTS OFF OVER THE REGION THEN RETROGRADES LATE IN THE PERIOD AS WESTERN ATLANTIC RIDGE BUILDS. AT THE SFC, HIGH PRES WILL BUILD OVER THE AREA AND DOMINATE OUR WEATHER THROUGH FRIDAY NIGHT WITH PRIMARILY DRY CONDITIONS. SATURDAY THROUGH SUNDAY, AN INCREASINGLY MOIST SOUTHEAST FLOW WILL DEVELOP LEADING TO HUMID CONDITIONS AND CHC POPS FOR CONVECTION. HIGHEST POPS WILL BE OVER THE EASTERN CWA IN AN AREA OF BETTER MOISTURE AND OROGRAPHIC LIFT. TEMPS THROUGH THE PERIOD WILL BE NEAR SEASONAL NORMS. && .AVIATION /16Z SUNDAY THROUGH THURSDAY/... MAIN CONCERN HEADING INTO TODAY WILL BE POSSIBLE SHWRS/STORM DEVELOPMENT LATER THIS AFTERNOON AS UPPER STORM SYSTEM APPROACHES FROM THE SOUTHWEST. FOR NOW...FEEL BULK OF THE MORNING HRS SHOULD BE PRECIP FREE WITH ACTIVITY THEN DEVELOPING AFTER 18Z. FCST GUIDANCE SUGGESTING WEAK INSTABILITY LATER THIS AFTERNOON AND THUS HAVE ADVERTISED A 3 HR TEMPO GROUP FOR THUNDER AT ALL SITES. MOVING INTO TONIGHT...DIURNAL STORMS SHOULD COME TO AN END BEFORE 00Z WITH BULK OF ACTIVITY THEN TRANSITIONING BACK TO PLAIN SHWRS. BEYOND 06Z...GUIDANCE SUGGESTS WIDESPREAD RESTRICTIONS DEVELOPING HOWEVER CONTINUED SOUTHWEST FLOW LENDS ONLY MARGINAL CONFIDENCE OF THIS SCENARIO DEVELOPING. DESPITE THIS...HAVE NUDGED TOWARDS LOW-END MVFR UNTIL BETTER CONFIDENCE ARRIVES WITH FUTURE MODEL GUIDANCE. .OUTLOOK... MONDAY THROUGH THURSDAY...SCT SHRA/TSRA ARE ANTICIPATED EACH AFTN/EVE...WITH BRIEF RESTRICTIONS PSBL. MVFR RESTRICTIONS ALSO PSBL IN EARLY MRNG STRATUS/FOG. OTRW VFR PREVAILS. THU...VFR. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...PVN NEAR TERM... SHORT TERM...PVN LONG TERM...RRM AVIATION...CMG
AREA FORECAST DISCUSSION
NWS BUFFALO NY
1012 AM EDT SUN JUL 7 2013 .SYNOPSIS... A BERMUDA HIGH ANCHORED OFF THE EAST COAST COMBINED WITH A MID LEVEL LOW OVER THE OHIO VALLEY WILL KEEP A SOUTHERLY FLOW OF WARM AND VERY MOIST AIR THROUGH THE REMAINDER OF THE WEEKEND WITH SCATTERED SHOWERS AND THUNDERSTORMS...ESPECIALLY INLAND FROM THE LAKES. THE UNSETTLED WEATHER WILL CONTINUE THROUGH THE MIDDLE OF NEXT WEEK BEFORE DRIER AIR FINALLY ARRIVES BY THE END OF THE WEEK AS HIGH PRESSURE BUILDS INTO THE GREAT LAKES. && .NEAR TERM /THROUGH TONIGHT/... RADAR LOOP SHOWS A COMPLEX OF SHOWERS ASSOCIATED WITH A MID-LEVEL SHORTWAVE EXITING TO THE EAST LATE THIS MORNING. AS THIS EXITS...THERE WILL LIKELY BE SOME DRYING IN ITS WAKE AS 700 MB WINDS DIMINISH WHICH PROMOTE MID-LEVEL DIVERGENCE. THE MAJORITY OF MODEL GUIDANCE DID NOT CAPTURE THIS FEATURE...AND AS SUCH PROBABLY WILL NOT CAPTURE THE SUBSIDENCE IN PLACE BEHIND THE EXITING WAVE. THE 06Z GFS AND HRRR DID CAPTURE THIS FEATURE...AND AS A RESULT WILL BE HEAVILY WEIGHTED FOR TODAY/S FORECAST. FOR THE REMAINDER OF TODAY...THERE MAY BE A FEW LINGERING SHOWERS EAST OF LAKE ONTARIO IN ASSOCIATION WITH WEAK WARM ADVECTION THROUGH LATE MORNING. OTHERWISE THIS MORNING SHOULD BE DRY. DAYTIME HEATING WILL RESULT IN INCREASING INSTABILITY TODAY. FOLLOWING THE GFS/HRRR GUIDANCE WHICH IS FAIRLY WELL ALIGNED WITH LATEST WATER VAPOR IMAGERY...EXPECT THE LARGE SCALE AND/OR ORGANIZED CONVECTION TO TRACK TO OUR SOUTH AND EAST THIS AFTERNOON. THIS WILL AGAIN LEAVE MORE SUBTLE MESOSCALE FEATURES WHICH PROVIDE THE FOCUS FOR CONVECTION FOR OUR AREA THIS AFTERNOON. WITH THE ABOVE IN MIND...HAVE GONE WITH SCATTERED SHOWERS AND ISOLATED THUNDER AGAIN FOR THE AFTERNOON FROM THE WESTERN SOUTHERN TIER INTO THE FINGER LAKES. FARTHER NORTH...EXPECT MOST OF THE NIAGARA FRONTIER EAST TO ROCHESTER TO REMAIN DRY GIVEN THE DEVELOPING LAKE SHADOW AND LESS DEEP LAYER MOISTURE. IT WILL BE ANOTHER WARM AND VERY MUGGY DAY WITH LOWER ELEVATIONS AWAY FROM LAKE INFLUENCES REACHING THE MID 80S...WITH SOME SPOTS IN CENTRAL NY REACHING THE UPPER 80S. THE HIGHER TERRAIN...NORTH COUNTRY...AND LAKESHORES WILL BE A LITTLE COOLER...BUT STILL VERY MUGGY. FROM A SYNOPTIC STANDPOINT...THE BERMUDA HIGH WILL REMAIN IN PLACE FOR THE NEXT 24 HOURS AND BEYOND AS THE CUTOFF LOW OVER THE WESTERN OHIO VALLEY ACCELERATES EAST AND REACHES WESTERN PA BY DAYBREAK MONDAY AS IT RE-ENGAGES WITH THE WESTERLIES. THIS CUTOFF...AND THE ASSOCIATED MID LEVEL TROUGH WILL BECOME THE MAIN FORECAST PLAYER LATER TONIGHT. THIS EVENING THE SHOWERS FROM THE WESTERN SOUTHERN TIER INTO CENTRAL NY WILL SLOWLY DIMINISH AND PUSH EAST WITH THE LOSS OF DAYTIME HEATING AND PASSAGE OF THE SUPPORTING SHORTWAVE. THE MAIN MID LEVEL LOW WILL MAKE PROGRESS OVERNIGHT...REACHING WESTERN PA BY DAYBREAK MONDAY. THE APPROACH OF THE MID LEVEL TROUGH WILL BRING AN INCREASE IN LARGE SCALE ASCENT OVERNIGHT...AND A 900-700MB TROUGH DROPPING SOUTHEAST OUT OF CANADA WILL LIKELY PROVIDE CONVERGENCE AND FOCUS FOR A DEVELOPING AREA OF SHOWERS AND SCATTERED STORMS LATE TONIGHT. WITH THIS IN MIND...HAVE RAMPED UP POPS TO LIKELY BY LATE TONIGHT WITH THE APPROACH OF THIS FEATURE. IT WILL BE ANOTHER MUGGY NIGHT WITH LOWS AROUND 70 ON THE LAKE PLAINS AND MID TO UPPER 60S FARTHER INLAND. && .SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/... THE UPPER THROUGH WHICH HAS BEEN IN PLACE OVER THE MIDWESTERN STATES WILL CONTINUE TO MOVE SLOWLY TO THE EAST AND TRACK ACROSS NEW YORK STATE AND PA ON MONDAY. THE LIFT ASSOCIATED WITH THE SHORT WAVE TROUGH WILL HAVE THE GREATEST IMPACT ON OUR AREA MONDAY MORNING...BEFORE IT SHIFTS INTO EASTERN NEW YORK STATE AND NEW ENGLAND DURING THE AFTERNOON. A WEAK WAVE THAT WILL BE TRACKING EAST ACROSS A FRONT...STALLED JUST TO OUR NORTH...WILL GENERATE ADDITIONAL LIFT AND WILL HELP TO FOCUS THE ABUNDANT LOW LEVEL MOISTURE THAT STILL WILL BE IN PLACE. BASED ON THESE TRENDS...EXPECT A HIGH LIKELIHOOD OF SHOWERS AND SCATTERED THUNDERSTORMS MONDAY MORNING. AS THE PRIMARY SOURCES OF LIFT SHIFT TO OUR EAST DURING THE AFTERNOON...WE SHOULD SEE A WEST TO EAST DECREASE IN PCPN. WITH PRECIPITABLE WATER VALUES FORECAST TO RANGE FROM 1.5 INCH TO 1.75 INCH...ANY CONVECTION MAY PRODUCE HEAVY RAIN...BUT THERE SHOULD BE SUFFICIENT DIRECTIONAL SHEAR TO KEEP CELLS FROM TRAINING OVER THE SAME SMALL AREAS ALONG THE STORM TRACKS... LIMITING THE FLOOD THREAT. AS THE UPPER SHORT WAVE TROUGH CONTINUES TO MOVE TO THE EAST MONDAY NIGHT...WEAK RIDGING SHOULD PROVIDE US WITH MAINLY DRY WEATHER. HIGH PRESSURE WILL REMAIN IN CONTROL FOR MOST OF TUESDAY...BUT LATE DAY SHOWERS AND THUNDERSTORMS ARE POSSIBLE IN THE FAR WEST AS A WARM FRONT AND SHORT WAVE MOVE EAST TOWARD THE LOWER LAKES. INCREASING MOISTURE (PWATS FORECAST TO RISE TO ABOUT 2 INCHES) AHEAD OF THE WARM FRONT AND ADDED LIFT IN THE VICINITY OF THE SHORT WAVE TROUGH WILL BRING A GOOD CHANCE FOR SHOWERS AND THUNDERSTORMS TUESDAY NIGHT AND WEDNESDAY. UNSETTLED WEATHER WILL CONTINUE WEDNESDAY NIGHT AS A COLD FRONT...TRAILING SOUTH OF LOW PRESSURE NEAR JAMES BAY...PUSHES EAST ACROSS THE STATE. TEMPERATURES ON MONDAY WILL BE CLOSE TO SEASONAL AVERAGES. WARMER TEMPERATURES RETURN ON TUESDAY AND WEDNESDAY...ALONG WITH AN INCREASE IN HUMIDITY...ESPECIALLY ON WEDNESDAY. && .LONG TERM /THURSDAY THROUGH SATURDAY/... A TRANSITION TO A HIGHER AMPLITUDE PATTERN ALOFT WILL TAKE PLACE DURING THIS PERIOD...CHARACTERIZED BY A DIGGING TROUGH OVER THE GREAT LAKES WHILE A RIDGE BUILDS OUT WEST. THIS PATTERN SHIFT WILL RESULT IN A TREND TOWARD SLIGHTLY COOLER TEMPERATURES AND LOWER HUMIDITY AS THE WEEK PROGRESSES. AT THE SURFACE...THE COLD FRONT THAT WILL BE PUSHING EAST ACROSS THE AREA WEDNESDAY NIGHT WILL REACH THE EAST COAST ON THURSDAY. WHILE DRIER AIR WILL WORK IN BEHIND THE FRONT...COOLER AIR ASSOCIATED WITH THE DEEPENING UPPER LEVEL TROUGH MAY GENERATE ENOUGH INSTABILITY FOR A FEW MORE SHOWERS. THE LATEST GUIDANCE NOW SUGGESTS THAT THE UPPER LEVEL TROUGH WILL CUTOFF AND SETTLE OVER THE OHIO VALLEY AND LOWER LAKES FRIDAY AND SATURDAY. AT THE SAME TIME...HIGH PRESSURE AT THE SURFACE IS FORECAST TO BUILD EAST ACROSS THE GREAT LAKES. WHILE THE TROUGH MAY ENHANCE INSTABILITY...THIS SYSTEM MAY BE STARVED FOR MOISTURE. THEREFORE...WILL MAINTAIN ONLY LOW CHANCE OR SLIGHT CHANCE POPS FOR FRIDAY AND SATURDAY. MOST OF THE RESULTANT RAIN FROM THIS WILL BE ASSOCIATED WITH AN OFFSHORE COASTAL SYSTEM. && .AVIATION /14Z SUNDAY THROUGH THURSDAY/... AN AREA OF SHOWERS AND A FEW EMBEDDED THUNDERSTORMS WHICH CROSSED THE AREA DURING THE WEE HOURS OF THE MORNING IS RACING EAST INTO EASTERN NY AND WEAKENING THIS MORNING. A FEW LEFTOVER MAINLY LIGHT SHOWERS WILL CONTINUE ACROSS THE SAINT LAWRENCE VALLEY THROUGH LATE MORNING...OTHERWISE THE REST OF THE AREA WILL REMAIN DRY. MOSTLY VFR CONDITIONS WILL PREVAIL...ALTHOUGH A FEW PATCHES OF MVFR CIGS NEAR KBUF-KIAG WILL PERSIST THROUGH MID MORNING. ANOTHER MID LEVEL DISTURBANCE AND PLUME OF MOISTURE IS FORECAST TO CROSS THE WESTERN SOUTHERN TIER AND FINGER LAKES LATER IN THE AFTERNOON AND EARLY EVENING...AND THIS MAY PRODUCE ADDITIONAL SCATTERED SHOWERS AND ISOLATED STORMS INCLUDING KJHW. CONDITIONS WILL BE VFR MOST OF THE TIME...BUT ANY SHOWER OR THUNDERSTORM WILL BRIEFLY DIP CIGS/VSBY TO MVFR/IFR. A SOUTHWEST FLOW OFF LAKES ERIE AND ONTARIO SHOULD AID IN STABILIZING THE ATMOSPHERE ENOUGH TO KEEP THE RISK OF SHOWERS LOW AT THE REST OF THE TAF SITES. THIS EVENING ANY SHOWERS ACROSS THE SOUTHERN TIER AND FINGER LAKES WILL WEAKEN. LATE TONIGHT YET ANOTHER MID LEVEL TROUGH WILL APPROACH THE REGION AND TOUCH OFF MORE SHOWERS AND A FEW THUNDERSTORMS. AGAIN MOST OF THE NIGHT SHOULD BE VFR...BUT BRIEF MVFR/IFR IS POSSIBLE IN ANY OF THE HEAVIER SHOWERS. OUTLOOK... MONDAY THROUGH WEDNESDAY...MAINLY VFR WITH SCATTERED SHOWERS AND THUNDERSTORMS AND ASSOCIATED BRIEF MVFR/IFR CONDITIONS. THURSDAY...VFR. && .MARINE... SOUTHWEST WINDS WILL INCREASE SOME TODAY...ESPECIALLY ON LAKE ERIE WHERE THE SOUTHWEST FLOW WILL CHANNEL UP THE LAKE. THIS WILL PRODUCE CHOPPY WAVES IN THE 2-4 FOOT RANGE. FOR NOW WILL KEEP CONDITIONS JUST BELOW SMALL CRAFT ADVISORY CRITERIA BUT THIS WILL NEED TO BE MONITORED. LIGHT TO MODERATE SOUTHWEST WINDS WILL CONTINUE TONIGHT THROUGH MONDAY WITH CHOPPY WAVE ACTION AT TIMES ON BOTH LAKE...BUT CONDITIONS SHOULD REMAIN BELOW SMALL CRAFT CRITERIA. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...NONE. MARINE...NONE. && $$ SYNOPSIS...HITCHCOCK NEAR TERM...APFFEL/HITCHCOCK SHORT TERM...TJP LONG TERM...TJP AVIATION...HITCHCOCK MARINE...APFFEL/HITCHCOCK
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
854 AM EDT SUN JUL 7 2013 .SYNOPSIS... WARM AND HUMID CONDITIONS WILL PERSIST OVER THE REGION THROUGH MONDAY WITH SCATTERED SHOWERS AND THUNDERSTORMS, PRIMARILY DURING THE AFTERNOON. SINCE THE AIRMASS REMAINS VERY MOIST ANY THUNDERSTORMS MAY PRODUCE LOCALIZED HEAVY RAINFALL. THE UPPER LEVEL TROUGH WILL EXIT THE NORTHEASTERN UNITED STATES MONDAY NIGHT BRINGING A BRIEF END TO THE RAIN. && .NEAR TERM /THROUGH TONIGHT/... 845 AM UPDATE... EARLY MRNG MCS HAS MOVD EAST AND IS ENTERING WRN NEW ENGLAND...WITH FCST AREA UNDER PC SKIES. TDA`S SCENARIO IS NOT MUCH DIFFERENT FROM PREV DAYS. UPR LOW OVER INDIANA THIS MRNG WITH S/WV`S ROTATING NEWD FROM THE ERN OH VLY INTO THE NE U.S.. NXT S/WV IS OVER WRN WV WHICH WILL BE HEADING NEWD TWDS WRN NY LATE TDA. OTHER THAN THIS FEATURE...THERE IS NOT MUCH TO FOCUS CONVECTIVE DVLPMNT TDA OTHER THAN ANY MESO-BETA BNDRYS AND TRRN FEATURES. IN THE NEAR TERM WE LOWERED POPS INTO EARLY AFTN AND REMOVED ANY QPF BEFORE 18Z...THEN CHC POPS THIS AFTN FOR SCT SHRA/TSRA. WIND SHEAR TDA IS MARGINAL FOR ORGANIZED STORMS AND IS ACTUALLY LOWERING THIS MRNG INTO EARLY AFTN...BUT INCREASES TO MARGINALLLY SUPPORTIVE VALUES ACRS WRN ZONES LATE TDA WITH APRCH OF NXT S/WV. GIVEN MOIST CONDITIONS...LCL +RA WILL BE MAIN THREAT WITH ANY STORMS TDA. PREV BLO... 630 AM UPDATE... JUST DID ANOTHER MAJOR RE-WORK OF THE POPS GRIDS AS S/WV IS EXITING STAGE RIGHT AT THIS TIME, TAKING THE STORMS WITH IT IN THE NEXT HR. BASED ON LATEST RUC FCST AND CURRENT TRENDS NOT EXPECTING MUCH IN THE WAY OF SHOWERS TO GET IN HERE BFR 15Z AND ONLY SCTD, AT BEST, AFTER THAT TIME. 520 AM UPDATE... QUICK UPDATE TO UP POPS ACRS UPSTATE NY TO 50% FOR CLUSTER OF TSTMS MVG THRU NRN ZONES. ALSO UPPED QPF TO AROUND 0.25 INCHES BASIN-AVERAGE THRU 12Z THO LOCALLY HIGHER AMNTS MAY EXIST. 330 AM UPDATE... BERMUDA RIDGE CONTS TO SPIN OFF THE ATLANTIC COAST WITH PLENTIFUL MOISTURE BEING PUMPED INTO CWA FM GOM. UL TROF/LOW IS ON THE MV AS RIDGE IS WEAKENING. S/WV LOCATED ACRS OH/KY AREA WL APPCH THE FA THIS AFTN AND RESULT IN A GOOD CHC FOR SHRA/TSRA ACTIVITY. THUS WL GO WITH LKLY POPS ACRS WRN ZONES ARND 18Z OR SO THEN DIMINISHING AFT THAT AS WV PASSES OFF TO THE WEST AND MID-LVL LAPSE RATES WEAKEN. AS FOR SVR POTENTIAL, EXPECT ONLY A STRONG STORM OR TWO AS 0-6KM BULK SHEAR VALUES WEAKEN THRU THE DAY. ANY TSTM THAT CAN DVLP WL HV THE POTENTIAL TO PRODUCE TORRENTIAL DOWNPOURS AND LOCALIZED FLOODING AND THIS WL LKLY BE THE MAIN THREAT FOR THIS AFTN. H8 TEMPS TO ARND 17C TDA WL YIELD HIGHS IN THE M/U 80S SIMILAR TO YDA. FOR TONIGHT, UL LOW WL OPEN UP ACRS NRN OHIO BY 06Z AND BEGIN TO EJECT EAST WITH SCTD THUNDER RMNG ACRS THE REGION THRU 12Z MONDAY. EXPECTING OVRNGT MINS TO RMN UP IN THE U60S WITH DWPTS RMNG JUST A DEGREE OR TWO LOWER. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... 330 AM UPDATE... UPR TROF WL BE EJECTING OUT DRG THE DAY ON MONDAY WITH PW VALUES GRADUALLY DROPPING THRU THE AFTN. POTENTIAL EXISTS FOR LCLY HVYR RAINFALL THRU THE COURSE OF THE DAY WITH UL TROF INTERACTING WITH FRONTAL BNDRY ACRS THE NERN U.S. THIS, IN ADDITION TO SATURATED SOIL CONDS WL BRING A HEIGHTENED THREAT FOR FLOODING ON MONDAY. THUS, WL HIGHLIGHT THREAT IN THE HWO. PCPN SHUD GRADUALLY WIND DOWN MON NGT AS FLOW TRANSITIONS TO A MORE ZONAL FLOW ALOFT. DIURNAL CONVECTION WL ONCE AGAIN BE POSSIBLE TUE AFTN BFR TAPERING OFF TUE NGT, AHD OF NEXT H5 TROF HEADED IN FM THE WEST. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... A FAIRLY ACTIVE WX PATTERN EXPECTED TO PERSIST RIGHT THROUGH THE CONCLUSION OF THE LONG TERM PERIOD AS A STRONG COLD FRONT PASSES THROUGH THE AREA ON EARLY THURSDAY...FOLLOWED BY A AN UPPER CLOSED LOW STALLING OVER THE TENNESSEE VALLEY BY WEEK/S END. MODELS REMAIN IN EXCELLENT AGREEMENT ON THE TIMING OF THE AFOREMENTIONED COLD FRONT WITH THE GFS...ECMWF AND CANADIAN-CMC SOLUTIONS ALL FAVORING AN LATE WED/EARLY THU MORNING PASSAGE. FROM THIS VANTAGE POINT...THE SLIGHTLY EARLIER FROPA TIMING FROM YESTERDAY/S RUNS WILL LIKELY YIELD LITTLE THREAT FOR SEVERE WX AS THE FRONT SHOULD BE EAST OF MUCH OF THE FORECAST AREA BY THU AFTERNOON/S PEAK HEATING CYCLE. REGARDLESS...HAVE MAINTAINED LIKELY POPS BOTH WED NGT AND THU AS MODELS SHOW PLENTY OF QPF IN THE WARM SECTOR PRIOR TO AND DURING FRONTAL PASSAGE. BY FRI...FCST MODELS SHOW SFC HIGH PRESSURE BUILDING INTO THE REGION WHICH SHOULD YIELD OF BRIEF REPRIEVE FROM SHWR ACTIVITY. BY THE WEEKEND...BOTH GFS AND ECMWF SUGGEST UPPER-LEVEL ENERGY WILL GRADUALLY SHEAR OFF FROM MAIN UPPER FLOW RESULTING IN THE DEVELOPMENT OF A CLOSED UPPER LOW WHICH WILL GRADUALLY RETROGRADE WEST FROM THE CENTRAL/NORTHERN APPALACHIANS INTO THE TENNESSEE AND OHIO VLYS. AS THIS OCCURS...FCST GUIDANCE SHOWS A DEVELOPING FETCH OF ATLANTIC MOISTURE WORKING NORTHWEST INTO THE MID-ATLANTIC REGION WHICH SHOULD LEAD TO REDEVELOPING SHWRS BY NEXT WEEKEND. && .AVIATION /13Z SUNDAY THROUGH THURSDAY/... MAIN CONCERN HEADING INTO TODAY WILL BE POSSIBLE SHWRS/STORM DEVELOPMENT LATER THIS AFTERNOON AS UPPER STORM SYSTEM APPROACHES FROM THE SOUTHWEST. FOR NOW...FEEL BULK OF THE MORNING HRS SHOULD BE PRECIP FREE WITH ACTIVITY THEN DEVELOPING AFTER 18Z. FCST GUIDANCE SUGGESTING WEAK INSTABILITY LATER THIS AFTERNOON AND THUS HAVE ADVERTISED A 3 HR TEMPO GROUP FOR THUNDER AT ALL SITES. MOVING INTO TONIGHT...DIURNAL STORMS SHOULD COME TO AN END BEFORE 00Z WITH BULK OF ACTIVITY THEN TRANSITIONING BACK TO PLAIN SHWRS. BEYOND 06Z...GUIDANCE SUGGESTS WIDESPREAD RESTRICTIONS DEVELOPING HOWEVER CONTINUED SOUTHWEST FLOW LENDS ONLY MARGINAL CONFIDENCE OF THIS SCENARIO DEVELOPING. DESPITE THIS...HAVE NUDGED TOWARDS LOW-END MVFR UNTIL BETTER CONFIDENCE ARRIVES WITH FUTURE MODEL GUIDANCE. .OUTLOOK... MONDAY THROUGH THURSDAY...SCT SHRA/TSRA ARE ANTICIPATED EACH AFTN/EVE...WITH BRIEF RESTRICTIONS PSBL. MVFR RESTRICTIONS ALSO PSBL IN EARLY MRNG STRATUS/FOG. OTRW VFR PREVAILS. THU...VFR. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...PVN NEAR TERM... SHORT TERM...PVN LONG TERM...CMG AVIATION...CMG
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
702 AM EDT SUN JUL 7 2013 .SYNOPSIS... WARM AND HUMID CONDITIONS WILL PERSIST OVER THE REGION THROUGH MONDAY WITH SCATTERED SHOWERS AND THUNDERSTORMS, PRIMARILY DURING THE AFTERNOON. SINCE THE AIRMASS REMAINS VERY MOIST ANY THUNDERSTORMS MAY PRODUCE LOCALIZED HEAVY RAINFALL. THE UPPER LEVEL TROUGH WILL EXIT THE NORTHEASTERN UNITED STATES MONDAY NIGHT BRINGING A BRIEF END TO THE RAIN. && .NEAR TERM /THROUGH TONIGHT/... 630 AM UPDATE... JUST DID ANOTHER MAJOR RE-WORK OF THE POPS GRIDS AS S/WV IS EXITING STAGE RIGHT AT THIS TIME, TAKING THE STORMS WITH IT IN THE NEXT HR. BASED ON LATEST RUC FCST AND CURRENT TRENDS NOT EXPECTING MUCH IN THE WAY OF SHOWERS TO GET IN HERE BFR 15Z AND ONLY SCTD, AT BEST, AFTER THAT TIME. 520 AM UPDATE... QUICK UPDATE TO UP POPS ACRS UPSTATE NY TO 50% FOR CLUSTER OF TSTMS MVG THRU NRN ZONES. ALSO UPPED QPF TO AROUND 0.25 INCHES BASIN-AVERAGE THRU 12Z THO LOCALLY HIGHER AMNTS MAY EXIST. 330 AM UPDATE... BERMUDA RIDGE CONTS TO SPIN OFF THE ATLANTIC COAST WITH PLENTIFUL MOISTURE BEING PUMPED INTO CWA FM GOM. UL TROF/LOW IS ON THE MV AS RIDGE IS WEAKENING. S/WV LOCATED ACRS OH/KY AREA WL APPCH THE FA THIS AFTN AND RESULT IN A GOOD CHC FOR SHRA/TSRA ACTIVITY. THUS WL GO WITH LKLY POPS ACRS WRN ZONES ARND 18Z OR SO THEN DIMINISHING AFT THAT AS WV PASSES OFF TO THE WEST AND MID-LVL LAPSE RATES WEAKEN. AS FOR SVR POTENTIAL, EXPECT ONLY A STRONG STORM OR TWO AS 0-6KM BULK SHEAR VALUES WEAKEN THRU THE DAY. ANY TSTM THAT CAN DVLP WL HV THE POTENTIAL TO PRODUCE TORRENTIAL DOWNPOURS AND LOCALIZED FLOODING AND THIS WL LKLY BE THE MAIN THREAT FOR THIS AFTN. H8 TEMPS TO ARND 17C TDA WL YIELD HIGHS IN THE M/U 80S SIMILAR TO YDA. FOR TONIGHT, UL LOW WL OPEN UP ACRS NRN OHIO BY 06Z AND BEGIN TO EJECT EAST WITH SCTD THUNDER RMNG ACRS THE REGION THRU 12Z MONDAY. EXPECTING OVRNGT MINS TO RMN UP IN THE U60S WITH DWPTS RMNG JUST A DEGREE OR TWO LOWER. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... 330 AM UPDATE... UPR TROF WL BE EJECTING OUT DRG THE DAY ON MONDAY WITH PW VALUES GRADUALLY DROPPING THRU THE AFTN. POTENTIAL EXISTS FOR LCLY HVYR RAINFALL THRU THE COURSE OF THE DAY WITH UL TROF INTERACTING WITH FRONTAL BNDRY ACRS THE NERN U.S. THIS, IN ADDITION TO SATURATED SOIL CONDS WL BRING A HEIGHTENED THREAT FOR FLOODING ON MONDAY. THUS, WL HIGHLIGHT THREAT IN THE HWO. PCPN SHUD GRADUALLY WIND DOWN MON NGT AS FLOW TRANSITIONS TO A MORE ZONAL FLOW ALOFT. DIURNAL CONVECTION WL ONCE AGAIN BE POSSIBLE TUE AFTN BFR TAPERING OFF TUE NGT, AHD OF NEXT H5 TROF HEADED IN FM THE WEST. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... A FAIRLY ACTIVE WX PATTERN EXPECTED TO PERSIST RIGHT THROUGH THE CONCLUSION OF THE LONG TERM PERIOD AS A STRONG COLD FRONT PASSES THROUGH THE AREA ON EARLY THURSDAY...FOLLOWED BY A AN UPPER CLOSED LOW STALLING OVER THE TENNESSEE VALLEY BY WEEK/S END. MODELS REMAIN IN EXCELLENT AGREEMENT ON THE TIMING OF THE AFOREMENTIONED COLD FRONT WITH THE GFS...ECMWF AND CANADIAN-CMC SOLUTIONS ALL FAVORING AN LATE WED/EARLY THU MORNING PASSAGE. FROM THIS VANTAGE POINT...THE SLIGHTLY EARLIER FROPA TIMING FROM YESTERDAY/S RUNS WILL LIKELY YIELD LITTLE THREAT FOR SEVERE WX AS THE FRONT SHOULD BE EAST OF MUCH OF THE FORECAST AREA BY THU AFTERNOON/S PEAK HEATING CYCLE. REGARDLESS...HAVE MAINTAINED LIKELY POPS BOTH WED NGT AND THU AS MODELS SHOW PLENTY OF QPF IN THE WARM SECTOR PRIOR TO AND DURING FRONTAL PASSAGE. BY FRI...FCST MODELS SHOW SFC HIGH PRESSURE BUILDING INTO THE REGION WHICH SHOULD YIELD OF BRIEF REPRIEVE FROM SHWR ACTIVITY. BY THE WEEKEND...BOTH GFS AND ECMWF SUGGEST UPPER-LEVEL ENERGY WILL GRADUALLY SHEAR OFF FROM MAIN UPPER FLOW RESULTING IN THE DEVELOPMENT OF A CLOSED UPPER LOW WHICH WILL GRADUALLY RETROGRADE WEST FROM THE CENTRAL/NORTHERN APPALACHIANS INTO THE TENNESSEE AND OHIO VLYS. AS THIS OCCURS...FCST GUIDANCE SHOWS A DEVELOPING FETCH OF ATLANTIC MOISTURE WORKING NORTHWEST INTO THE MID-ATLANTIC REGION WHICH SHOULD LEAD TO REDEVELOPING SHWRS BY NEXT WEEKEND. && .AVIATION /12Z SUNDAY THROUGH THURSDAY/... MAIN CONCERN HEADING INTO TODAY WILL BE POSSIBLE SHWRS/STORM DEVELOPMENT LATER THIS AFTERNOON AS UPPER STORM SYSTEM APPROACHES FROM THE SOUTHWEST. FOR NOW...FEEL BULK OF THE MORNING HRS SHOULD BE PRECIP FREE WITH ACTIVITY THEN DEVELOPING AFTER 18Z. FCST GUIDANCE SUGGESTING WEAK INSTABILITY LATER THIS AFTERNOON AND THUS HAVE ADVERTISED A 3 HR TEMPO GROUP FOR THUNDER AT ALL SITES. MOVING INTO TONIGHT...DIURNAL STORMS SHOULD COME TO AN END BEFORE 00Z WITH BULK OF ACTIVITY THEN TRANSITIONING BACK TO PLAIN SHWRS. BEYOND 06Z...GUIDANCE SUGGESTS WIDESPREAD RESTRICTIONS DEVELOPING HOWEVER CONTINUED SOUTHWEST FLOW LENDS ONLY MARGINAL CONFIDENCE OF THIS SCENARIO DEVELOPING. DESPITE THIS...HAVE NUDGED TOWARDS LOW-END MVFR UNTIL BETTER CONFIDENCE ARRIVES WITH FUTURE MODEL GUIDANCE. .OUTLOOK... MONDAY THROUGH THURSDAY...SCT SHRA/TSRA ARE ANTICIPATED EACH AFTN/EVE...WITH BRIEF RESTRICTIONS PSBL. MVFR RESTRICTIONS ALSO PSBL IN EARLY MRNG STRATUS/FOG. OTRW VFR PREVAILS. THU...VFR. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...PVN NEAR TERM...PVN SHORT TERM...PVN LONG TERM...CMG AVIATION...CMG
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
629 AM EDT SUN JUL 7 2013 .SYNOPSIS... WARM AND HUMID CONDITIONS WILL PERSIST OVER THE REGION THROUGH MONDAY WITH SCATTERED SHOWERS AND THUNDERSTORMS, PRIMARILY DURING THE AFTERNOON. SINCE THE AIRMASS REMAINS VERY MOIST ANY THUNDERSTORMS MAY PRODUCE LOCALIZED HEAVY RAINFALL. THE UPPER LEVEL TROUGH WILL EXIT THE NORTHEASTERN UNITED STATES MONDAY NIGHT BRINGING A BRIEF END TO THE RAIN. && .NEAR TERM /THROUGH TONIGHT/... 630 AM UPDATE... JUST DID ANOTHER MAJOR RE-WORK OF THE POPS GRIDS AS S/WV IS EXITING STAGE RIGHT AT THIS TIME, TAKING THE STORMS WITH IT IN THE NEXT HR. BASED ON LATEST RUC FCST AND CURRENT TRENDS NOT EXPECTING MUCH IN THE WAY OF SHOWERS TO GET IN HERE BFR 15Z AND ONLY SCTD, AT BEST, AFTER THAT TIME. 520 AM UPDATE... QUICK UPDATE TO UP POPS ACRS UPSTATE NY TO 50% FOR CLUSTER OF TSTMS MVG THRU NRN ZONES. ALSO UPPED QPF TO AROUND 0.25 INCHES BASIN-AVERAGE THRU 12Z THO LOCALLY HIGHER AMNTS MAY EXIST. 330 AM UPDATE... BERMUDA RIDGE CONTS TO SPIN OFF THE ATLANTIC COAST WITH PLENTIFUL MOISTURE BEING PUMPED INTO CWA FM GOM. UL TROF/LOW IS ON THE MV AS RIDGE IS WEAKENING. S/WV LOCATED ACRS OH/KY AREA WL APPCH THE FA THIS AFTN AND RESULT IN A GOOD CHC FOR SHRA/TSRA ACTIVITY. THUS WL GO WITH LKLY POPS ACRS WRN ZONES ARND 18Z OR SO THEN DIMINISHING AFT THAT AS WV PASSES OFF TO THE WEST AND MID-LVL LAPSE RATES WEAKEN. AS FOR SVR POTENTIAL, EXPECT ONLY A STRONG STORM OR TWO AS 0-6KM BULK SHEAR VALUES WEAKEN THRU THE DAY. ANY TSTM THAT CAN DVLP WL HV THE POTENTIAL TO PRODUCE TORRENTIAL DOWNPOURS AND LOCALIZED FLOODING AND THIS WL LKLY BE THE MAIN THREAT FOR THIS AFTN. H8 TEMPS TO ARND 17C TDA WL YIELD HIGHS IN THE M/U 80S SIMILAR TO YDA. FOR TONIGHT, UL LOW WL OPEN UP ACRS NRN OHIO BY 06Z AND BEGIN TO EJECT EAST WITH SCTD THUNDER RMNG ACRS THE REGION THRU 12Z MONDAY. EXPECTING OVRNGT MINS TO RMN UP IN THE U60S WITH DWPTS RMNG JUST A DEGREE OR TWO LOWER. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... 330 AM UPDATE... UPR TROF WL BE EJECTING OUT DRG THE DAY ON MONDAY WITH PW VALUES GRADUALLY DROPPING THRU THE AFTN. POTENTIAL EXISTS FOR LCLY HVYR RAINFALL THRU THE COURSE OF THE DAY WITH UL TROF INTERACTING WITH FRONTAL BNDRY ACRS THE NERN U.S. THIS, IN ADDITION TO SATURATED SOIL CONDS WL BRING A HEIGHTENED THREAT FOR FLOODING ON MONDAY. THUS, WL HIGHLIGHT THREAT IN THE HWO. PCPN SHUD GRADUALLY WIND DOWN MON NGT AS FLOW TRANSITIONS TO A MORE ZONAL FLOW ALOFT. DIURNAL CONVECTION WL ONCE AGAIN BE POSSIBLE TUE AFTN BFR TAPERING OFF TUE NGT, AHD OF NEXT H5 TROF HEADED IN FM THE WEST. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... A FAIRLY ACTIVE WX PATTERN EXPECTED TO PERSIST RIGHT THROUGH THE CONCLUSION OF THE LONG TERM PERIOD AS A STRONG COLD FRONT PASSES THROUGH THE AREA ON EARLY THURSDAY...FOLLOWED BY A AN UPPER CLOSED LOW STALLING OVER THE TENNESSEE VALLEY BY WEEK/S END. MODELS REMAIN IN EXCELLENT AGREEMENT ON THE TIMING OF THE AFOREMENTIONED COLD FRONT WITH THE GFS...ECMWF AND CANADIAN-CMC SOLUTIONS ALL FAVORING AN LATE WED/EARLY THU MORNING PASSAGE. FROM THIS VANTAGE POINT...THE SLIGHTLY EARLIER FROPA TIMING FROM YESTERDAY/S RUNS WILL LIKELY YIELD LITTLE THREAT FOR SEVERE WX AS THE FRONT SHOULD BE EAST OF MUCH OF THE FORECAST AREA BY THU AFTERNOON/S PEAK HEATING CYCLE. REGARDLESS...HAVE MAINTAINED LIKELY POPS BOTH WED NGT AND THU AS MODELS SHOW PLENTY OF QPF IN THE WARM SECTOR PRIOR TO AND DURING FRONTAL PASSAGE. BY FRI...FCST MODELS SHOW SFC HIGH PRESSURE BUILDING INTO THE REGION WHICH SHOULD YIELD OF BRIEF REPRIEVE FROM SHWR ACTIVITY. BY THE WEEKEND...BOTH GFS AND ECMWF SUGGEST UPPER-LEVEL ENERGY WILL GRADUALLY SHEAR OFF FROM MAIN UPPER FLOW RESULTING IN THE DEVELOPMENT OF A CLOSED UPPER LOW WHICH WILL GRADUALLY RETROGRADE WEST FROM THE CENTRAL/NORTHERN APPALACHIANS INTO THE TENNESSEE AND OHIO VLYS. AS THIS OCCURS...FCST GUIDANCE SHOWS A DEVELOPING FETCH OF ATLANTIC MOISTURE WORKING NORTHWEST INTO THE MID-ATLANTIC REGION WHICH SHOULD LEAD TO REDEVELOPING SHWRS BY NEXT WEEKEND. && .AVIATION /12Z SUNDAY THROUGH THURSDAY/... AREA RADARS THIS MORNING SHOWING DEVELOPING CONVECTION THIS HR ACROSS WESTERN NY IN ADVANCE OF A SHORTWAVE DISTURBANCE LIFTING NORTH THROUGH EASTERN OHIO. SO FAR THIS ACTIVITY HAS SHOWN A WEAKENING TREND AS IT PROGRESSES EAST AND THUS HAVE NOT HIGHLIGHTED THUNDER IN ANY TERMINALS OUT OF THE GATE THIS MORNING. OBVIOUSLY TRENDS WILL HAVE TO BE WATCHED WITH AND UPDATES MADE ON AN AS NEEDED BASIS. UPSTREAM SATELLITE TRENDS ALSO SHOWING SOME PARTIAL CLEARING WORKING NORTH FROM EASTERN PA THIS HR. AS A RESULT...MAIN CONCERN FOR THE NEXT 6-HRS IN ADDITION TO THE CONVECTION WILL BE THE POSSIBILITY FOR IFR VSBYS IN FOG AS WE PROGRESS THROUGH THE MORNING. FOR NOW HAVE ADVERTISED BELOW ALTERNATE MIN CONDITIONS DEVELOPING AT THE TERMINAL WITH DIURNAL IMPROVEMENTS LIKELY AFTER 11Z IF FOG DOES DEVELOP. ELSEWHERE...MVFR VSBYS POSSIBLE AT ITH AND AVP AFTER THE 09Z TIME FRAME. SHWRS EXPECTED TO BECOME MORE PREVALENT AS THE DAY CONTINUES AS A STRONG UPPER-LEVEL DISTURBANCES GRADUALLY APPROACHES THE AREA. STORMS WILL ALSO BE POSSIBLE BUT HAVE ELECTED TO HOLD OFF MENTIONING FOR NOW BASED ON DISTANCE INTO THE FCST AND MARGINAL CONFIDENCE. WINDS WILL REMAIN FROM THE WEST BETWEEN 5-10 KTS THROUGH THE PERIOD BEFORE WEAKENING THIS EVENING. .OUTLOOK... MONDAY THROUGH THURSDAY...SCT SHRA/TSRA ARE ANTICIPATED EACH AFTN/EVE...WITH BRIEF RESTRICTIONS PSBL. MVFR RESTRICTIONS ALSO PSBL IN EARLY MRNG STRATUS/FOG. OTRW VFR PREVAILS. THU...VFR. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...PVN NEAR TERM...PVN SHORT TERM...PVN LONG TERM...CMG AVIATION...CMG
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
350 PM EDT SUN JUL 7 2013 .SYNOPSIS... THE BERMUDA HIGH WILL CONTINUE TO AFFECT THE LOCAL WEATHER THRU OUT THE UPCOMING WEEK...HOWEVER ITS POSITIONING WILL SLIDE SLIGHTLY FURTHER OFFSHORE DURING THE WEEK. THIS WILL ALLOW A COLD FRONT TO SLOWLY APPROACH FROM THE NORTHWEST BY THE NEXT UPCOMING WEEKEND. TYPICAL SUMMERTIME WEATHER WITH DAILY AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS WILL OCCUR EACH DAY...INCREASING IN COVERAGE AS WE APPROACH NEXT WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... AS OF 300 PM SUNDAY...HIGH PRESSURE RIDGING INTO COASTAL CAROLINAS FROM THE ATLANTIC WILL SHIFT SLIGHTLY EAST THROUGH TODAY. THIS WILL ALLOW THE WINDS TO SHIFT TO MORE OF A SOUTH DIRECTION INLAND WITH MORE OF A SOUTHEAST FLOW ALONG THE COAST...ENHANCED WITH AFTN SEA BREEZE. STILL SEEING PLENTY OF DRY AIR THROUGH THE MID TO UPPER LEVELS THROUGH TODAY WITH MOISTURE CONFINED TO LOW LEVELS BELOW 5K FT. FLOW HAS VEERED SLIGHTLY THROUGH THE LOW LEVELS COMING AROUND TO SOUTHWEST ABOVE THE SURFACE UP THROUGH H85. THIS HAS KEPT BEST CONVERGENCE AROUND THE RIDGE CLOSER TO THE COAST WHICH IN TURN HAS KEPT CLOUDS AND SHOWERS FROM PUSHING WELL INLAND. CONTINUE TO EXPECT GOOD DEAL OF SUNSHINE ACROSS MUCH OF THE AREA WITH ONLY ISOLATED SHWRS/TSTMS MAINLY ALONG SEA BREEZE BOUNDARY AND FURTHER INLAND ASSOCIATED WITH CONVERGENCE AROUND HIGH. HRRR SHOWING QUITE A FEW SHOWERS OVER SC THIS AFTERNOON...REMAINING MAINLY WEST OF I95. DRIER AIR WILL CONTINUE TO PUSH INLAND WITH PROGRESSION OF SEA BREEZE. MODELS SHOW PCP WATER VALUES UP CLOSE TO 1.7 INCHES INLAND THIS AFTN DROPPING DOWN TO 1.2 INCHES BY LATE THIS EVENING. THEREFORE CLOUDS AND ISOLATED SHOWERS THAT DEVELOP ALONG THIS BOUNDARY AS IT PROGRESSES INLAND...WILL LEAVE MOST OF THE COAST CLEAR BY THIS AFTERNOON AND INLAND AREAS BY LATE THIS EVENING. TEMPS BETWEEN 85 AND 90 MOST PLACES WILL DROP SLOWLY THROUGH THE EVENING. EXPECT OVERNIGHT LOWS TO BE BETWEEN 70 AN 75 WITH SLIGHTLY WARMER TEMPS RIGHT ALONG THE COAST WHERE WARMER OCEAN WATERS WILL KEEP THEM HIGHER. MOISTURE PROFILES SHOW SOME UPPER LEVEL MOISTURE INCREASING TONIGHT AS THE UPPER TROUGH CURRENTLY OVER SOUTHERN ILLINOIS LIFTS NORTHEAST PRODUCING A MORE NW FLOW IN THE UPPER ATMOSPHERE. THIS WILL PRODUCE SOME CIRRUS BY MORNING BUT OVERALL EXPECT MAINLY CLEAR SKIES. HAVE INCLUDED MENTION OF PATCHY FOG BUT LEFT OUT ANY SHOWERS...ALTHOUGH CAN NOT RULE OUT AN ISOLATED SHOWER OR TWO MOVING ON SHORE. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 300 PM SUNDAY...THE WESTERN ATLANTIC RIDGING BOTH SFC AND ALOFT AND HAVING PROVIDED THE TROPICAL WX TYPE CONDITIONS DURING THIS EXTENDED JULY 4TH WEEKEND...WILL WEAKEN ACROSS THE AREA MONDAY INTO TUESDAY. THIS A RESULT OF THE SLIGHT PROGRESSION OF WX FEATURES BOTH ALOFT AND AT THE SFC. THE UPPER RIDGE AXIS AND THE CENTER OF THE ASSOCIATED WESTERN ATLANTIC SFC HIGH...AKA BERMUDA HIGH...IS PROGGED BY THE MODELS TO SLIDE FURTHER OFFSHORE FROM THE CAROLINA COASTS. THE ORIENTED LOWER TO MID MISSISSIPPI AND OHIO RIVER UPPER TROF IS PROGGED TO FLATTEN SOME AS THE MAIN VORT FINALLY PROGRESSES NE TO E...STAYING WELL NORTH OF THE FA DURING THIS SHORT TERM PERIOD. WHAT FINALLY ENDS UP IS A LOW AMPLITUDE UPPER TROUGHINESS ALONG THE SPINE OF THE APPALACHIANS FROM VA SOUTHWESTWARD...AND LEE SIDE SFC TROFFINESS ACROSS THE CAROLINAS. THE SFC RIDGE AXIS EXTENDING SW-W FROM THE OFFSHORE BERMUDA HIGH WILL EVENTUALLY DROP SOUTH OF THE ILM CWA. THE TRUE ATLANTIC TROPICAL ATM REGIME OF THE PAST SEVERAL DAYS WILL FINALLY COME PARTIALLY TO AN END. WITH THE ADDITION OF CONVECTIVE FOCUS MECHANISMS BESIDES THE SEA BREEZE FOR MON AND TUE AS WELL AS BETTER INSTABILITY...POPS WILL SLOWLY INCREASE BUT REMAIN CAPPED IN THE CHANCE CATEGORY. POPS WILL PEAK DURING THE AFTN/EARLY EVENING AIDED BY THE DAYS HEATING. THE NOCTURNAL TROPICAL REGIME TYPE CONVECTION OVER THE ATL WATERS OF THE PAST SEVERAL DAYS WILL NO LONGER HAVE A STRAIGHT LINE SHOT TO THE IMMEDIATE COAST DURING PRE-DAWN TUE...AND PRE-DAWN WED. HOWEVER BY PRE-DAWN WED...A SFC TROF WILL HAVE REACHED THE ATLANTIC WATERS OFF THE SE U.S. COAST...WHICH IS A REFLECTION FROM AN UPPER LOW THAT TRAVERSES THE BAHAMAS MON AND PARTIALLY ACROSS FLORIDA TUE. MOISTURE ASSOCIATED WITH THIS FEATURE COULD REACH THE ATL WATERS AND PUSH PARTIALLY ON SHORE LATE ON THE PRE-DAWN WED HOURS. THIS WILL NEED TO BE MONITORED. FOR MAX TEMPS MON AND TUE...GUIDANCE REMAINS RATHER CLUSTERED WITH MID 80S ALONG THE IMMEDIATE COAST...UPPER 80S TO AROUND 90 FROM THE COAST TO THE I-95 CORRIDOR...AND LOWER 90S WEST OF THE I-95 CORRIDOR. FOR MIN TEMPS BOTH MORNINGS...A 70 TO 75 RANGE...THE EXCEPTION WILL BE THE IMMEDIATE COAST WHERE MID 70S TO RULE BOTH DAYS. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... AS OF 300 PM SUNDAY...WHILE THE BEGINNING OF THE PERIOD WILL CONTINUE WITH WARM SUMMER CONDITIONS AND ONLY ISOLATED CONVECTION...A PATTERN REGIME CHANGE WILL OCCUR BY THE END OF THE WEEK...AND A RENEWED WET PERIOD IS BECOMING MORE LIKELY FOR THE WKND. BERMUDA HIGH AT THE SURFACE AND FLAT RIDGING ALOFT WILL CREATE ONE LAST DAY OF TEMPS AT TO ABOVE CLIMO WITH A LOT OF SUNSHINE AND LITTLE CONVECTION. THEREAFTER...UPPER TROUGHING BEGINS TO BUILD DOWN FROM THE NORTHWEST AND ACROSS THE EASTERN CONUS. WHILE THE COLD FRONT ASSOCIATED WITH THIS UPPER TROUGH WILL LIKELY GET HELD UP AND WASH OUT JUST NORTH OF THE LOCAL AREA...DECREASING HEIGHTS ALOFT WILL STEEPEN LAPSE RATES...LEADING TO INCREASING CONVECTIVE POTENTIAL. AT THE SAME TIME...TROPICAL WAVE WHICH HAS BEEN PROGGED TO MOVE BENEATH THE BERMUDA HIGH AND INTO FLORIDA WILL FEED SOME OF ITS MOISTURE INTO THE CAROLINAS BEGINNING FRIDAY. THIS ENHANCED MOISTURE...PWATS RISING TO OVER 2 INCHES...COMBINED WITH THE STEEPER LR`S IN THE MID-LEVELS WILL SUPPORT EVEN MORE SIGNIFICANT CONVECTION ON FRIDAY. DO NOT ANTICIPATE A SEVERE THREAT ATTM...BUT HEAVY RAIN WILL BE POSSIBLE. MAX TEMPS WILL REMAIN AROUND CLIMO THROUGH THE END OF THE WEEK...WITH LOWS HOVERING A FEW DEGREES ABOVE. WEATHER COULD DETERIORATE MORE CONSIDERABLY FOR NEXT WEEKEND. 5H TROUGH CLOSES OFF IN RESPONSE TO STRONG AMPLIFICATION OF THE FLOW...AND BLOCKING RIDGE ACROSS THE WESTERN ATLANTIC. THIS FORCES THE CLOSED LOW TO RETROGRADE TO THE WEST...WITH DEEP SOUTHERLY FLOW ONCE AGAIN DEVELOPING ACROSS THE SOUTHEAST. IN A PATTERN EERILY REMINISCENT OF THE END OF JUNE...CLOSED LOW ACROSS THE TN VLY WITH BLOCKING HIGH OVER THE OCEAN WILL DRIVE TROPICAL MOISTURE INTO THE REGION AND A WET PERIOD AGAIN LOOKS TO BE IN STORE. FORTUNATELY...AT LEAST FOR D6/D7...IT DOES NOT LOOK QUITE AS ROBUST AS THE PATTERN WE SAW TO CLOSE OUT JUNE...BUT AN EXTENDED PERIOD OF UNSETTLED WEATHER LOOKS LIKELY FOR NEXT WKND. && .AVIATION /19Z SUNDAY THROUGH FRIDAY/... AS OF 18Z...HIGH PRESSURE OFFSHORE WILL CONTINUE TO GIVE US SOUTH SOUTHEAST FLOW THROUGH THE PERIOD. NO FOG EXPECTED WITH WINDS AT THE BOUNDARY LAYER 15+ KTS. MONDAY...MODELS INDICATE HIGH LEVEL MOISTURE RETURNING...WITH BROKEN CIRRUS EXPECTED ALL DAY. WINDS WILL BE A BIT MORE SOUTHWESTERLY. EXTENDED OUTLOOK...EARLY MORNING IFR/MVFR CIGS/VSBYS POSSIBLE THROUGH THE EXTENDED PERIOD. INCREASING CHANCES FOR SHOWERS AND THUNDERSTORMS THURSDAY AND FRIDAY. OTHERWISE EXPECT VFR. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 300 PM SUNDAY...SOUTHERLY RETURN FLOW 10 TO 15 KTS WILL PERSIST ACROSS THE WATERS AROUND THE PERIPHERY OF BERMUDA HIGH PRESSURE. THE WINDS WILL ACTUALLY VEER EVER SO SLIGHTLY FROM S-SE TO S-SW BY MORNING REMAINING AROUND 10 KTS FOR THE MOST PART. AN 8 SECOND SE SWELL WILL CONTINUE TO MIX WITH LOCALLY GENERATED WIND WAVES TO PRODUCE TOTAL SEAS OF 2 TO 3 FT. SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 300 PM SUNDAY...THE WESTERN ATLANTIC HIGH...AKA BERMUDA HIGH...WILL REMAIN THE PRIMARY INFLUENCE OF THE WINDS ACROSS THE LOCAL WATERS. THE DEVELOPMENT OF THE LEE-SIDE TROF ACROSS THE WESTERN AND CENTRAL CAROLINAS...AND THE SFC RIDGE AXIS THAT EXTENDS SW-W FROM THE CENTER OF THE BERMUDA HIGH OFFSHORE...IS PROGGED TO DROP SOUTH OF THE LOCAL WATERS THIS TIME PERIOD. THEREFORE...A SW WIND DIRECTION WILL EVENTUALLY BECOME THE DOMINANT WIND DIRECTION. THE DAILY SEA BREEZE WILL TEMPORARILY BACK WINDS TO A MORE SOUTHERLY DIRECTION EACH AFTN/EVENING. WITH THE CENTER OF THE HIGH FURTHER AWAY AND OFFSHORE FROM THE ILM WATERS...THE SFC PG WILL SLIGHTLY TIGHTEN. BASICALLY LOOKING AT WIND SPEEDS IN THE 10 TO 15 KT RANGE...WITH THE SEA BREEZE ADDING 5 KT OF SPEED NEARSHORE EACH AFTN AND EVENING...THUS REACHING 15 TO POSSIBLY 20 KT. SIGNIFICANT SEAS WILL HOVER AROUND THE 3 FOOT HEIGHT THRU-OUT THE SHORT TERM. THERE WILL BE LESS OF AN INFLUENCE FROM THE 6 TO 8 SECOND PERIOD SE SWELL DUE TO FETCH LIMITATIONS...BUT AN INCREASED INFLUENCE FROM THE 3 TO 5 SECOND PERIOD WIND DRIVEN WAVES. THIS WILL FINALLY BEGIN TO LOWER THE RIP CURRENT RISK...RELATIVELY SPEAKING. IN ADDITION...BOATERS NAVIGATING TO AND FROM THE ATL THRU AREA INLETS WILL ALSO IMPROVE...SOME ESPECIALLY WHEN TRAVERSING THESE WATERS DURING AN OUT-GOING TIDE. LONG TERM /WEDNESDAY THROUGH FRIDAY/... AS OF 300 PM SUNDAY...BERMUDA HIGH OFFSHORE PERSISTS DURING THE EXTENDED...KEEPING SW WINDS ONGOING ACROSS THE WATERS. WHILE THE GRADIENT ON THE WESTERN SIDE OF THIS RIDGE REMAINS RELATIVELY WEAK...IT DOES SLOWLY STRENGTHEN LATE IN THE WEEK IN RESPONSE TO A COLD FRONT DRIFTING SLOWLY TOWARDS THE AREA. WHILE THIS FRONT WILL LIKELY NOT MAKE IT TO THE WATERS...AND INSTEAD WASH OUT ACROSS THE CENTRAL CAROLINAS FRIDAY...THE PINCHING GRADIENT WILL HELP WINDS INCREASE FROM 10-15 KTS WEDNESDAY TO 15-20 KTS THURSDAY AND FRIDAY. THE SE SWELL WILL SLOWLY DECAY THROUGH THE PERIOD...BUT SW WIND WAVES WILL GRADUALLY INCREASE IN AMPLITUDE. SEAS WILL BUILD FROM 2-3 FT WEDNESDAY...TO AS MUCH AS 4-5 FT LATE THURSDAY INTO FRIDAY...AND A SCEC MAY BE REQUIRED FOR A PORTION OF THE PERIOD. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...HIGH RIP CURRENT RISK UNTIL 8 PM EDT THIS EVENING FOR SCZ054. NC...HIGH RIP CURRENT RISK UNTIL 8 PM EDT THIS EVENING FOR NCZ106- 108-110. MARINE...NONE. && $$ SYNOPSIS...DCH NEAR TERM...RGZ SHORT TERM...DCH LONG TERM...JDW AVIATION...RGZ/DL
AREA FORECAST DISCUSSION
NWS RALEIGH NC
240 PM EDT SUN JUL 7 2013 .SYNOPSIS... A WEAKENING UPPER LEVEL LOW WILL PROGRESS EAST ACROSS THE MID- ATLANTIC TONIGHT. CYCLONIC FLOW ALOFT WILL PREVAIL OVER THE EASTERN UNITED STATES THROUGH MID WEEK...WITH AN UNSEASONABLY DEEP UPPER LEVEL TROUGH DIGGING SOUTHEAST IN THE MID-ATLANTIC BY FRIDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 240 PM SUNDAY... SOME VERY LIGHT SHOWERS REMAIN IN THE NORTHEAST PIEDMONT...BUT THE STRONGER STORMS AND BETTER COVERAGE REMAINS JUST WEST OF THE TRIAD. AS WITH YESTERDAY...THE HRRR HIGH RES CAM IS DOING THE BEST AT SIMULATING THE CURRENT SHOWER ACTIVITY...ALTHOUGH THE TIMING MAY BE A BIT OFF. HIGH PRESSURE REMAINS OFF THE CAROLINA COAST...WITH THE LOW WEST OF THE APPALACHIANS OVER IL/IN. LOW LEVEL MOISTURE IS ADVECTING INTO WESTERN NC OFF THE GULF AHEAD OF THE LOW PRESSURE SYSTEM. AS THE UPPER LEVEL LOW CONTINUES TO MOVE EASTWARD INTO PA TONIGHT...SMALL AMPLITUDE SHORTWAVES WILL TRACK NORTHEAST ACROSS WESTERN NC/VA. IN ADDITION TO THE SHORTWAVES...MOISTURE CONVERGENCE ALONG THE PIEDMONT TROUGH ARE THE LIKELY DRIVING MECHANISMS FOR THE CONVECTION MOVING INTO THE TRIAD. CURRENT ANALYZED MLCAPE VALUES RANGE FROM 1500-2000 J/KC ACROSS CENTRAL NC...WITH THE BEST CAPE DISPLACED FROM THE BEST SHEAR (OVER THE MTNS). BEST CHANCES FOR SHOWERS/STORMS WILL REMAIN IN THE WEST THROUGH TONIGHT. THERE IS THE POTENTIAL FOR SOME STORMS TO PRODUCE DAMAGING WINDS THIS AFT/EVE... MAINLY IN AND AROUND THE TRIAD WHERE THE DCAPE IS ANALYZED AROUND 1000 J/KG AND 0-6 KM SHEAR VALUES AROUND 30 KTS. LOWS TONIGHT SIMILAR TO PREVIOUS NIGHTS IN THE LOWER 70S. && .SHORT TERM /MONDAY AND MONDAY NIGHT/... AS OF 240 PM SUNDAY... AS THE UPPER LEVEL LOW MAKES ITS WAY ACROSS PA AND INTO NEW ENGLAND MONDAY AND MONDAY NIGHT...THE ASSOCIATED TROUGH WILL MOVE INTO CENTRAL NC...THUS DAMPENING THE HIGH AND PUSHING THE RIDGE AXIS SOUTH AND EAST. THE MAIN SHOWER ACTIVITY WILL SHIFT SLOWLY EASTWARD THROUGH THE DAY AND INTO THE EVENING MONDAY AS ADDITIONAL SHORTWAVE DISTURBANCES MOVE OVER THE AREA. HIGHEST PRECIP CHANCES COINCIDE WITH PEAK HEATING...AND WILL DECREASE SUBSTANTIALLY AFTER SUNSET. HIGH TEMPS WILL BE SIMILAR TO TODAY...MID 80S NW INCREASING TO NEAR 90 IN THE EAST. OVERNIGHT LOWS WILL AGAIN BE SIMILAR TO PREVIOUS NIGHTS...MAINLY IN THE LOW 70S. && .LONG TERM /TUESDAY THROUGH SUNDAY/... AS OF 230 PM SUNDAY... FOR TUESDAY/TUESDAY NIGHT: VERY WEAK MID LEVEL TROUGH AXIS HOLDS OVER THE EAST COAST WHILE A SUBTLE SURFACE TROUGH HOLDS OVER THE NC PIEDMONT. ABOVE-NORMAL DEEP MOISTURE PERSISTS ESPECIALLY SOUTH AND EAST OF THE TROUGH WITH PW VALUES RANGING FROM 1.7-2.0 INCHES FROM NW TO SE OVER CENTRAL NC. THE WEAK WIND FIELD (PROJECTED WINDS NO GREATER THAN 15 KTS BELOW 400 MB) THROUGHOUT THE MOIST COLUMN COMBINED WITH DAYTIME DESTABILIZATION (MLCAPE PEAKING AT 1200-2000 J/KG) SUGGEST SCATTERED STORMS DEVELOPING IN THE AFTERNOON WITH SLOW MOVEMENT AND THE POTENTIAL TO DUMP SOME HEAVY RAIN... GIVEN THE LCL-TO-0C LAYER DEPTH APPROACHING 3.8-4 KM. THE GFS/NAM/ECMWF GENERALLY FAVOR BETTER COVERAGE OVER THE SOUTHEAST CWA IN CONJUNCTION WITH THE GREATEST MOISTURE AND INSTABILITY... SO WILL EDGE POPS HIGHER THERE THAN IN THE REST OF THE CWA. SHOWERS/STORMS SHOULD FOLLOW A TYPICAL DIURNAL PATTERN OF TAPERING DOWN AFTER NIGHTFALL... ALTHOUGH WITH ANOMALOUSLY HIGH MOISTURE CONTINUING TO POOL OVER CENTRAL NC... A FEW MEANDERING SHOWERS AND ISOLATED STORMS MAY PERSIST OVERNIGHT. HIGHS 86-90. LOWS 70-73. FOR WEDNESDAY/WEDNESDAY NIGHT: THIS LOOKS TO BE THE TIME FRAME WITH A RELATIVE MINIMUM IN RAIN CHANCES... BUT CERTAINLY NOT ZERO CONSIDERING THE STILL-HIGH PW VALUES NEAR 2.0 INCHES. THE WESTERLIES TAKE A DIP INTO THE GREAT LAKES AS THE TROUGH BEGINS TO DIG TO OUR NORTHWEST... RESULTING A SLIGHT DOWNSTREAM REBOUNDING IN HEIGHTS OVER NC. GFS FORECAST SOUNDINGS SHOW A PERIOD OF MID LEVEL DRYING BETWEEN 800 AND 500 MB MAINLY IN THE EASTERN CWA... WHERE BOTH THE GFS AND ECMWF SHOW FAIRLY LOW QPF. WILL LEAVE IN CHANCE POPS... SKEWED HIGHER IN THE TRIAD AND LOWER IN THE SOUTHEAST... FOCUSED ON THE AFTERNOON/EVENING. HIGHS 87-91 AS THICKNESSES STAY NEAR CLIMATOLOGY. THE DEEPENING MID LEVEL TROUGH TO OUR WEST RESULTS IN AN UPTICK IN MID LEVEL WINDS OVER NW NC WEDNESDAY NIGHT... AND WITH MOISTURE REMAINING HIGH OR EVEN INCREASING A BIT OVER OUR NW CWA OVERNIGHT... WILL HOLD ONTO CHANCE POPS HERE WITH JUST A SLIGHT CHANCE ELSEWHERE. LOWS 70-74. FOR THURSDAY THROUGH SUNDAY: CONFIDENCE IS IMPROVING THAT THIS WILL BE A FAIRLY WET PERIOD. THE LONGWAVE TROUGH DIGS FURTHER THROUGH THE EASTERN GREAT LAKES AND OH VALLEY ON THURSDAY AS THE SURFACE COLD FRONT MOVES IN FROM THE NW... AND THE INCREASING DYNAMICS AND DEEP MOISTURE FLUX OVER NC WILL BRING INCREASING SHOWER/STORM COVERAGE FROM NW TO SE AS WE HEAD THROUGH THURSDAY AFTERNOON/NIGHT. THE MODELS CLOSE OFF A LOW TO OUR NORTHWEST... OVER WV/ERN KY/ERN TN... ON FRIDAY BEFORE DROPPING IT DOWN TO NRN GA/AL/MS OVER THE WEEKEND. SUCH A CLOSED LOW THAT FAR SOUTH IS HIGHLY UNUSUAL FOR THIS TIME OF YEAR (GEFS FORECAST 500 MB HEIGHTS OVER 2 STANDARD DEVIATIONS BELOW NORMAL OVER THE SOUTHEAST STATES)... SO IT IS SURPRISING HOW GOOD THE AGREEMENT IS BETWEEN THE OP GFS (12Z/07) AND ECMWF (00Z/07). WITH THE LOSS OF EASTWARD PUSH... THE SURFACE FRONT IS LIKELY TO STALL OUT OVER CENTRAL NC... AND WITH A STRENGTHENING AND DEEPENING SOUTHERLY FLOW ALLOWING 2.0+ INCH PW VALUES TO STREAK OVER CENTRAL NC FROM THURSDAY NIGHT THROUGH AT LEAST SATURDAY... WITH SOME DRYING POSSIBLE SUNDAY AS A LARGE AND STRONG MID LEVEL CYCLONE BUILDS FROM OFF THE CANADIAN MARITIMES SOUTHWESTWARD INTO NC. WILL KEEP HIGH RAIN CHANCES FOR THURSDAY NIGHT THROUGH SATURDAY... A BIT HIGHER IN THE AFTERNOON/EVENING BUT NOT YIELDING MUCH AT NIGHT... DROPPING BACK TOWARD CLIMATOLOGICAL POPS ON SUNDAY. EXPECT QUITE A BIT OF CLOUDINESS THROUGH THIS PERIOD WITH HUMID CONDITIONS REDUCING THE DIURNAL TEMP RANGE. LOWS AROUND 70-75 AND HIGHS IN THE LOW-MID 80S. -GIH && .AVIATION /18Z SUNDAY THROUGH THURSDAY/... AS OF 125 PM SUNDAY... 24-HR TAF PERIOD: CIGS HAVE BEEN BORDERLINE VFR/MVFR ALL DAY...BOUNCING BACK AND FORTH BETWEEN THE TWO...AND WILL LIKELY CONTINUE TO BE SO THROUGH MONDAY MORNING. LIGHT SHOWERS ARE OCCURRING AROUND KRDU...WITH HEAVIER SHOWERS AND POSSIBLE THUNDER MOVING INTO THE TRIAD (KINT AND KGSO) THIS AFTERNOON AND INTO THE OVERNIGHT HOURS. BEST CHANCE FOR LOW-END MVFR CIGS AT KINT AND KGSO DURING THE PRE-DAWN HOURS MONDAY...WITH THE POTENTIAL FOR A PERIOD OF BORDERLINE VFR/MVFR CIGS ELSEWHERE... ALTHOUGH CONFIDENCE IS LOW GIVEN THE DIFFERENCES IN MODEL GUIDANCE AT THIS TIME. THERE IS THE CHANCE FOR SHOWERS TO REDEVELOP ACROSS THE AREA MONDAY AFTERNOON/EVENING...BUT WILL LEAVE MENTION OUT OF TAFS FOR NOW. -KC LOOKING AHEAD: AVIATION CONDITIONS THROUGH MID/LATE WEEK WILL BE CHARACTERIZED BY AN ABOVE NORMAL CHANCE OF SHOWERS AND THUNDERSTORMS EACH DAY (PRIMARILY AFTERNOON AND EVENING HOURS) IN ASSOCIATION WITH CYCLONIC FLOW ALOFT AND AN ABOVE NORMAL CHANCE FOR MVFR/IFR STRATUS OR FOG EACH MORNING (PRIMARILY 07-13Z) IN ASSOCIATION WITH A PERSISTENT MOIST SOUTHERLY RETURN FLOW. -VINCENT && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...VINCENT NEAR TERM...KC SHORT TERM...KC LONG TERM...HARTFIELD AVIATION...KC/VINCENT
AREA FORECAST DISCUSSION
NWS RALEIGH NC
230 PM EDT SUN JUL 7 2013 .SYNOPSIS... A WEAKENING UPPER LEVEL LOW WILL PROGRESS EAST ACROSS THE MID- ATLANTIC TONIGHT. CYCLONIC FLOW ALOFT WILL PREVAIL OVER THE EASTERN UNITED STATES THROUGH MID WEEK...WITH AN UNSEASONABLY DEEP UPPER LEVEL TROUGH DIGGING SOUTHEAST IN THE MID-ATLANTIC BY FRIDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1025 AM SUNDAY... SOME VERY LIGHT SHOWERS HAVE DEVELOPED OVER THE SOUTHERN PIEDMONT AND SANDHILLS THIS MORNING. AS WITH YESTERDAY...THE HRRR HIGH RES CAM IS DOING A GOOD JOB SIMULATING THE CURRENT SHOWER ACTIVITY. THE LATEST RUN OF THE HRRR SHOWS AN INCREASE IN SHOWER COVERAGE...MAINLY IN THE NORTHEAST PIEDMONT AND SANDHILLS THROUGH THIS AFTERNOON... WITH THE MORE WIDESPREAD CONVECTION MOVING INTO THE NORTHWEST PIEDMONT LATE THIS AFT/EVE. 12Z UPPER AIR ANALYSES SHOW THE LOW WEST OF THE APPALACHIANS OVER IL/IN...WITH HIGH PRESSURE OFF THE CAROLINA COAST. WHILE CENTRAL NC IS RELATIVELY DRY...LOW LEVEL MOISTURE IS ADVECTING IN OFF THE GULF AHEAD OF THE LOW PRESSURE SYSTEM. AS THE UPPER LEVEL LOW MOVES EASTWARD TODAY SO WILL THE LOW/MID LEVEL MOISTURE AND SHOWERS/STORMS...CURRENTLY OVER THE MOUNTAINS. -KC PRECIPITATION CHANCES: SW FLOW ALOFT WILL STRENGTHEN FROM THE WEST TODAY...WITH AN INCREASING POTENTIAL FOR SMALL AMPLITUDE SHORTWAVES TRACKING NORTHEAST ACROSS WESTERN NC/VA THIS AFT/EVE...FOLLOWED BY ADDITIONAL DPVA WITHIN INCREASINGLY CYCLONIC FLOW ALOFT AS THE UPPER LEVEL LOW TRACKS INTO WESTERN PA BETWEEN 00-06Z TONIGHT. SHALLOW CONVERGENCE IN VICINITY OF A DEVELOPING PIEDMONT SFC TROUGH ASSOCIATED WITH SUBTLE HEIGHT FALLS IN ADVANCE OF THE UPPER LEVEL WAVE APPROACHING THE REGION THIS AFT/EVE WILL SERVE AS A POTENTIAL FOCUS FOR DIURNAL CONVECTION THIS AFTERNOON...FOLLOWED BY SOMEWHAT DEEPER CONVERGENCE TONIGHT AS THE LOW-LEVEL TROUGH SHARPENS IN RESPONSE TO STRONGER HEIGHT FALLS /CYCLONIC FLOW ALOFT/ OVER THE MID-ATLANTIC. SEASONAL BOUNDARY LAYER MOISTURE/DESTABILIZATION CAN BE EXPECTED AGAIN THIS AFTERNOON...WITH MLCAPE VALUES GENERALLY IN THE 1000-2000 J/KG RANGE ACROSS CENTRAL NC...THOUGH A WEST-EAST MID-LEVEL MOISTURE GRADIENT WILL PERSIST WITH DEEPER MOISTURE ACROSS THE FOOTHILLS/WESTERN PIEDMONT AND A DRIER AIRMASS ALOFT IN THE COASTAL PLAIN. WITH THE ABOVE IN MIND...EXPECT THE BEST CHANCE FOR CONVECTION THIS AFTERNOON AND EARLY EVENING WEST OF THE HWY 1 CORRIDOR IN VICINITY OF THE PIEDMONT SFC TROUGH AND IN CLOSER PROXIMITY TO SMALL AMPLITUDE SHORTWAVES/DEEPER MOISTURE IN STRENGTHENING SW FLOW ALOFT. WILL INDICATE PRECIP CHANCES RANGING FROM 20% EAST OF I-95 TO 50-60% IN THE FAR W/NW PIEDMONT. CONVECTION SHOULD PERSIST INTO TONIGHT ACROSS THE NORTHERN AND WESTERN PIEDMONT AS BETTER DPVA /STRONGER CYCLONIC FLOW ALOFT/ PROGRESSES INTO THE MID-ATLANTIC. TEMPERATURES: EXPECT HIGHS TODAY SIMILAR TO PREVIOUS DAYS WITH VERY SIMILAR REASONING...THOUGH PERHAPS SLIGHTLY WARMER GIVEN A MORE SOUTHWESTERLY LOW-LEVEL FLOW...ESP. ALONG AND EAST OF THE HWY 1 CORRIDOR...WITH HIGHS RANGING FROM THE MID 80S FAR NW PIEDMONT TO UPPER 80S AND LOWER 90S ELSEWHERE. LOWS TONIGHT SIMILAR TO PREVIOUS NIGHTS IN THE LOWER 70S. SEVERE THREAT: GIVEN DEEP LAYER SHEAR IN THE 25-35 KT RANGE ACROSS THE N/NW PIEDMONT IN THE PRESENCE OF MODERATE INSTABILITY (1000-2000 J/KG MLCAPE) AND DCAPE VALUES PROGGED AS HIGH AS 1000-1500 J/KG THIS AFT AND EARLY EVE...ANTICIPATE A POTENTIAL FOR DAMAGING WINDS... PRIMARILY WEST AND NW OF THE TRIANGLE. -VINCENT && .SHORT TERM /MONDAY/... AS OF 325 AM SUNDAY... ALTHOUGH THE AFOREMENTIONED UPPER LEVEL WAVE WILL TRACK EAST THROUGH THE MID-ATLANTIC EARLY MONDAY MORNING...CYCLONIC FLOW ALOFT AND LOW-LEVEL TROUGHING WILL PERSIST ACROSS THE AREA MONDAY AFT/EVE...WITH ADDITIONAL SHORTWAVE ENERGY ANTICIPATED TO DIG SOUTHEAST INTO NC/VA IN VICINITY OF PEAK HEATING. AS A RESULT... EXPECT ABOVE NORMAL CHANCES FOR CONVECTION...PRIMARILY DURING THE AFTERNOON AND EVENING HOURS...WITH HIGHS SIMILAR TO PREVIOUS DAYS... IN THE MID/UPPER 80S TO NEAR 90F. -VINCENT && .LONG TERM /TUESDAY THROUGH SUNDAY/... AS OF 230 PM SUNDAY... FOR TUESDAY/TUESDAY NIGHT: VERY WEAK MID LEVEL TROUGH AXIS HOLDS OVER THE EAST COAST WHILE A SUBTLE SURFACE TROUGH HOLDS OVER THE NC PIEDMONT. ABOVE-NORMAL DEEP MOISTURE PERSISTS ESPECIALLY SOUTH AND EAST OF THE TROUGH WITH PW VALUES RANGING FROM 1.7-2.0 INCHES FROM NW TO SE OVER CENTRAL NC. THE WEAK WIND FIELD (PROJECTED WINDS NO GREATER THAN 15 KTS BELOW 400 MB) THROUGHOUT THE MOIST COLUMN COMBINED WITH DAYTIME DESTABILIZATION (MLCAPE PEAKING AT 1200-2000 J/KG) SUGGEST SCATTERED STORMS DEVELOPING IN THE AFTERNOON WITH SLOW MOVEMENT AND THE POTENTIAL TO DUMP SOME HEAVY RAIN... GIVEN THE LCL-TO-0C LAYER DEPTH APPROACHING 3.8-4 KM. THE GFS/NAM/ECMWF GENERALLY FAVOR BETTER COVERAGE OVER THE SOUTHEAST CWA IN CONJUNCTION WITH THE GREATEST MOISTURE AND INSTABILITY... SO WILL EDGE POPS HIGHER THERE THAN IN THE REST OF THE CWA. SHOWERS/STORMS SHOULD FOLLOW A TYPICAL DIURNAL PATTERN OF TAPERING DOWN AFTER NIGHTFALL... ALTHOUGH WITH ANOMALOUSLY HIGH MOISTURE CONTINUING TO POOL OVER CENTRAL NC... A FEW MEANDERING SHOWERS AND ISOLATED STORMS MAY PERSIST OVERNIGHT. HIGHS 86-90. LOWS 70-73. FOR WEDNESDAY/WEDNESDAY NIGHT: THIS LOOKS TO BE THE TIME FRAME WITH A RELATIVE MINIMUM IN RAIN CHANCES... BUT CERTAINLY NOT ZERO CONSIDERING THE STILL-HIGH PW VALUES NEAR 2.0 INCHES. THE WESTERLIES TAKE A DIP INTO THE GREAT LAKES AS THE TROUGH BEGINS TO DIG TO OUR NORTHWEST... RESULTING A SLIGHT DOWNSTREAM REBOUNDING IN HEIGHTS OVER NC. GFS FORECAST SOUNDINGS SHOW A PERIOD OF MID LEVEL DRYING BETWEEN 800 AND 500 MB MAINLY IN THE EASTERN CWA... WHERE BOTH THE GFS AND ECMWF SHOW FAIRLY LOW QPF. WILL LEAVE IN CHANCE POPS... SKEWED HIGHER IN THE TRIAD AND LOWER IN THE SOUTHEAST... FOCUSED ON THE AFTERNOON/EVENING. HIGHS 87-91 AS THICKNESSES STAY NEAR CLIMATOLOGY. THE DEEPENING MID LEVEL TROUGH TO OUR WEST RESULTS IN AN UPTICK IN MID LEVEL WINDS OVER NW NC WEDNESDAY NIGHT... AND WITH MOISTURE REMAINING HIGH OR EVEN INCREASING A BIT OVER OUR NW CWA OVERNIGHT... WILL HOLD ONTO CHANCE POPS HERE WITH JUST A SLIGHT CHANCE ELSEWHERE. LOWS 70-74. FOR THURSDAY THROUGH SUNDAY: CONFIDENCE IS IMPROVING THAT THIS WILL BE A FAIRLY WET PERIOD. THE LONGWAVE TROUGH DIGS FURTHER THROUGH THE EASTERN GREAT LAKES AND OH VALLEY ON THURSDAY AS THE SURFACE COLD FRONT MOVES IN FROM THE NW... AND THE INCREASING DYNAMICS AND DEEP MOISTURE FLUX OVER NC WILL BRING INCREASING SHOWER/STORM COVERAGE FROM NW TO SE AS WE HEAD THROUGH THURSDAY AFTERNOON/NIGHT. THE MODELS CLOSE OFF A LOW TO OUR NORTHWEST... OVER WV/ERN KY/ERN TN... ON FRIDAY BEFORE DROPPING IT DOWN TO NRN GA/AL/MS OVER THE WEEKEND. SUCH A CLOSED LOW THAT FAR SOUTH IS HIGHLY UNUSUAL FOR THIS TIME OF YEAR (GEFS FORECAST 500 MB HEIGHTS OVER 2 STANDARD DEVIATIONS BELOW NORMAL OVER THE SOUTHEAST STATES)... SO IT IS SURPRISING HOW GOOD THE AGREEMENT IS BETWEEN THE OP GFS (12Z/07) AND ECMWF (00Z/07). WITH THE LOSS OF EASTWARD PUSH... THE SURFACE FRONT IS LIKELY TO STALL OUT OVER CENTRAL NC... AND WITH A STRENGTHENING AND DEEPENING SOUTHERLY FLOW ALLOWING 2.0+ INCH PW VALUES TO STREAK OVER CENTRAL NC FROM THURSDAY NIGHT THROUGH AT LEAST SATURDAY... WITH SOME DRYING POSSIBLE SUNDAY AS A LARGE AND STRONG MID LEVEL CYCLONE BUILDS FROM OFF THE CANADIAN MARITIMES SOUTHWESTWARD INTO NC. WILL KEEP HIGH RAIN CHANCES FOR THURSDAY NIGHT THROUGH SATURDAY... A BIT HIGHER IN THE AFTERNOON/EVENING BUT NOT YIELDING MUCH AT NIGHT... DROPPING BACK TOWARD CLIMATOLOGICAL POPS ON SUNDAY. EXPECT QUITE A BIT OF CLOUDINESS THROUGH THIS PERIOD WITH HUMID CONDITIONS REDUCING THE DIURNAL TEMP RANGE. LOWS AROUND 70-75 AND HIGHS IN THE LOW-MID 80S. -GIH && .AVIATION /18Z SUNDAY THROUGH THURSDAY/... AS OF 125 PM SUNDAY... 24-HR TAF PERIOD: CIGS HAVE BEEN BORDERLINE VFR/MVFR ALL DAY...BOUNCING BACK AND FORTH BETWEEN THE TWO...AND WILL LIKELY CONTINUE TO BE SO THROUGH MONDAY MORNING. LIGHT SHOWERS ARE OCCURRING AROUND KRDU...WITH HEAVIER SHOWERS AND POSSIBLE THUNDER MOVING INTO THE TRIAD (KINT AND KGSO) THIS AFTERNOON AND INTO THE OVERNIGHT HOURS. BEST CHANCE FOR LOW-END MVFR CIGS AT KINT AND KGSO DURING THE PRE-DAWN HOURS MONDAY...WITH THE POTENTIAL FOR A PERIOD OF BORDERLINE VFR/MVFR CIGS ELSEWHERE... ALTHOUGH CONFIDENCE IS LOW GIVEN THE DIFFERENCES IN MODEL GUIDANCE AT THIS TIME. THERE IS THE CHANCE FOR SHOWERS TO REDEVELOP ACROSS THE AREA MONDAY AFTERNOON/EVENING...BUT WILL LEAVE MENTION OUT OF TAFS FOR NOW. -KC LOOKING AHEAD: AVIATION CONDITIONS THROUGH MID/LATE WEEK WILL BE CHARACTERIZED BY AN ABOVE NORMAL CHANCE OF SHOWERS AND THUNDERSTORMS EACH DAY (PRIMARILY AFTERNOON AND EVENING HOURS) IN ASSOCIATION WITH CYCLONIC FLOW ALOFT AND AN ABOVE NORMAL CHANCE FOR MVFR/IFR STRATUS OR FOG EACH MORNING (PRIMARILY 07-13Z) IN ASSOCIATION WITH A PERSISTENT MOIST SOUTHERLY RETURN FLOW. -VINCENT && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...VINCENT NEAR TERM...KC/VINCENT SHORT TERM...VINCENT LONG TERM...HARTFIELD AVIATION...KC/VINCENT
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
202 PM EDT SUN JUL 7 2013 .SYNOPSIS... BERMUDA HIGH PRESSURE WILL BRING DEEP BLUE SKIES TO THE EASTERN CAROLINAS INTO MONDAY. THE BERMUDA HIGH WILL SLIDE FURTHER OFFSHORE DURING THE WEEK ALLOWING A COLD FRONT TO SLOWLY APPROACH FROM THE NORTHWEST. TYPICAL SUMMERTIME WEATHER WITH DAILY AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS WILL OCCUR THROUGHOUT THE UPCOMING WEEK. STORM COVERAGE WILL INCREASE LATE IN THE WEEK AS THE COLD FRONT MOVES CLOSER. && .NEAR TERM /THROUGH TONIGHT/... AS OF 2 PM SUNDAY...HIGH PRESSURE RIDGING INTO COASTAL CAROLINAS FROM THE ATLANTIC WILL SHIFT SLIGHTLY EAST THROUGH TODAY. THIS WILL ALLOW THE WINDS TO SHIFT TO MORE OF A SOUTH DIRECTION INLAND WITH MORE OF A SOUTHEAST FLOW ALONG THE COAST...ENHANCED WITH AFTN SEA BREEZE. STILL SEEING PLENTY OF DRY AIR THROUGH THE MID TO UPPER LEVELS THROUGH TODAY WITH MOISTURE CONFINED TO LOW LEVELS BELOW 5K FT. FLOW HAS VEERED SLIGHTLY THROUGH THE LOW LEVELS COMING AROUND TO SOUTHWEST ABOVE THE SURFACE UP THROUGH H85. THIS HAS KEPT BEST CONVERGENCE AROUND THE RIDGE CLOSER TO THE COAST WHICH IN TURN HAS KEPT CLOUDS AND SHOWERS FROM PUSHING WELL INLAND. CONTINUE TO EXPECT GOOD DEAL OF SUNSHINE ACROSS MUCH OF THE AREA WITH ONLY ISOLATED SHWRS/TSTMS MAINLY ALONG SEA BREEZE BOUNDARY AND FURTHER INLAND ASSOCIATED WITH CONVERGENCE AROUND HIGH. HRRR SHOWING QUITE A FEW SHOWERS OVER SC THIS AFTERNOON...REMAINING MAINLY WEST OF I95. DRIER AIR WILL CONTINUE TO PUSH INLAND WITH PROGRESSION OF SEA BREEZE. MODELS SHOW PCP WATER VALUES UP CLOSE TO 1.7 INCHES INLAND THIS AFTN DROPPING DOWN TO 1.2 INCHES BY LATE THIS EVENING. THEREFORE CLOUDS AND ISOLATED SHOWERS THAT DEVELOP ALONG THIS BOUNDARY AS IT PROGRESSES INLAND...WILL LEAVE MOST OF THE COAST CLEAR BY THIS AFTERNOON AND INLAND AREAS BY LATE THIS EVENING. TEMPS BETWEEN 85 AND 90 MOST PLACES WILL DROP SLOWLY THROUGH THE EVENING. EXPECT OVERNIGHT LOWS TO BE BETWEEN 70 AN 75 WITH SLIGHTLY WARMER TEMPS RIGHT ALONG THE COAST WHERE WARMER OCEAN WATERS WILL KEEP THEM HIGHER. MOISTURE PROFILES SHOW SOME UPPER LEVEL MOISTURE INCREASING TONIGHT AS THE UPPER TROUGH CURRENTLY OVER SOUTHERN ILLINOIS LIFTS NORTHEAST PRODUCING A MORE NW FLOW IN THE UPPER ATMOSPHERE. THIS WILL PRODUCE SOME CIRRUS BY MORNING BUT OVERALL EXPECT MAINLY CLEAR SKIES. HAVE INCLUDED MENTION OF PATCHY FOG BUT LEFT OUT ANY SHOWERS...ALTHOUGH CAN NOT RULE OUT AN ISOLATED SHOWER OR TWO MOVING ON SHORE. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 3 AM SUNDAY...BERMUDA HIGH WILL REMAIN IN PLACE AT THE SURFACE WHILE ALOFT THE MID LEVEL RIDGE RETREATS EAST. PASSAGE OF SHORTWAVE TROUGH NORTH OF THE AREA MON INTO MON NIGHT DOES ALLOW FOR WESTWARD EXPANSION OF 5H RIDGE TUE THOUGH IN A WEAKENED STATE. WEAKENING MID LEVEL SUBSIDENCE ALONG WITH INCREASING MID LEVEL MOISTURE LEADS TO INCREASED COVERAGE OF SHOWERS AND THUNDERSTORMS DURING THE PERIOD. MON DEEPER DRY AIR NEAR THE COAST WILL KEEP HIGHEST COVERAGE WELL INLAND. AREA OF HIGHER POP EXPANDS EAST ON TUE AS DEEPER MOISTURE ALSO SPREADS EAST. IMMEDIATE COAST IS LIKELY TO REMAIN DRY BOTH DAYS BUT MORE COVERAGE IS EXPECTED FOR TUE. LATE IN THE PERIOD TROPICAL MOISTURE FROM WEAK WAVE AND 5H LOW ROUNDING PERIPHERY OF BERMUDA HIGH/5H RIDGE MAY SPREAD OVER THE SOUTHEAST. THIS COULD RESULT IN AN INCREASE IN NOCTURNAL CONVECTION ACROSS SC COAST AND NEAR SHORE WATERS TUE NIGHT. TEMPERATURES WILL BE NEAR TO SLIGHTLY ABOVE CLIMO. AWAY FROM THE COAST HIGHS WILL BE IN THE UPPER 80S TO LOWER 90S. LOWS WILL BE IN THE MID 70S WITH SOME ISOLATED LOWER 70S INLAND. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... AS OF 3 AM SUNDAY...PROGRESSIVE MID LEVEL FLOW AND BERMUDA HIGH WILL MAINTAIN TYPICAL SUMMERTIME CONDITIONS ACROSS THE CAROLINAS WED AND THU. TEMPERATURES WILL BE NEAR TO SLIGHTLY ABOVE CLIMO FOR THE FIRST HALF OF THE PERIOD WITH ISOLATED AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS. COVERAGE WED WILL BE LIMITED WITH STORM DEVELOPMENT DEPENDENT ON DIURNAL INSTABILITY AND WEAK LOW LEVEL CONVERGENCE. THU ACTIVITY SHOULD BE MORE WIDESPREAD AS MID LEVEL TROUGHING STARTS TO PUSH DOWN THE EAST COAST. DEVELOPMENT OF MID LEVEL TROUGHING WILL ALSO START ADVECTING DEEPER MOISTURE OVER THE SOUTHEAST...ENHANCING STORM COVERAGE. PRECIP CHANCES SIGNIFICANTLY INCREASE DURING THE SECOND HALF OF THE PERIOD AS EAST COAST MID LEVEL TROUGHING STRENGTHENS... EVENTUALLY BECOMING CUT OFF LATE IN THE PERIOD. AS 5H TROUGH DIGS DOWN THE EAST COAST FRI INTO SAT...PUSHING A COLD FRONT INTO THE REGION..A TROPICAL WAVE MOVES ACROSS CUBA AND INTO FL. TROPICAL MOISTURE FROM THE WAVE AND DEEP SOUTHERLY FLOW PUSH PRECIPITABLE WATER VALUES WELL OVER 2 INCHES. DEEP MOISTURE...WEAKLY DIVERGENT FLOW ALOFT AND STEEPENING LAPSE RATES COMBINED WITH CONVERGENCE ALONG DISSIPATING COLD FRONT SHOULD LEAD TO AN INCREASE IN CONVECTION COVERAGE FRI AND SAT. MARGINAL MID LEVEL LAPSE RATES DO NOT SUGGEST MUCH SEVERE WEATHER POTENTIAL BUT HEAVY RAIN IS LIKELY TO BE AN ISSUE. INCREASING MOISTURE AND CLOUD COVER FRI/SAT WILL HOLD HIGHS IN THE MID TO UPPER 80S BUT HELP KEEP LOWS IN THE LOW TO MID 70S. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... AS OF 18Z...HIGH PRESSURE OFFSHORE WILL CONTINUE TO GIVE US SOUTH SOUTHEAST FLOW THROUGH THE PERIOD. NO FOG EXPECTED WITH WINDS AT THE BOUNDARY LAYER 15+ KTS. MONDAY...MODELS INDICATE HIGH LEVEL MOISTURE RETURNING...WITH BROKEN CIRRUS EXPECTED ALL DAY. WINDS WILL BE A BIT MORE SOUTHWESTERLY. EXTENDED OUTLOOK...EARLY MORNING IFR/MVFR CIGS/VSBYS POSSIBLE THROUGH THE EXTENDED PERIOD. INCREASING CHANCES FOR SHOWERS AND THUNDERSTORMS THURSDAY AND FRIDAY. OTHERWISE EXPECT VFR. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 2 PM SUNDAY...SOUTHERLY RETURN FLOW 10 TO 15 KTS WILL PERSIST ACROSS THE WATERS AROUND THE PERIPHERY OF BERMUDA HIGH PRESSURE. THE WINDS WILL ACTUALLY VEER EVER SO SLIGHTLY FROM S-SE TO S-SW BY MORNING REMAINING AROUND 10 KTS FOR THE MOST PART. AN 8 SECOND SE SWELL WILL CONTINUE TO MIX WITH LOCALLY GENERATED WIND WAVES TO PRODUCE TOTAL SEAS OF 2 TO 3 FT. SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 3 AM SUNDAY...BERMUDA HIGH WILL MAINTAIN SOUTH TO SOUTHWEST FLOW OVER THE WATERS THROUGH THE PERIOD. LITTLE CHANGE TO SURFACE PRESSURE GRADIENT WILL KEEP SPEEDS IN THE 10 TO 15 KT RANGE. SEAS WILL RUN 2 TO 3 FT A MIX OF SOUTHEAST SWELL AND SOUTHERLY WIND WAVE. LONG TERM /WEDNESDAY THROUGH THURSDAY/... AS OF 3 AM SUNDAY...DOMINANT SURFACE FEATURE THROUGH THE PERIOD CONTINUES TO BE BERMUDA HIGH BUT GRADIENT WILL TIGHTEN UP FOR THE SECOND HALF OF THE PERIOD. ON WED SPEEDS WILL REMAIN 10 TO 15 KT WITH WEAK GRADIENT IN PLACE. COLD FRONT SLOWLY APPROACHING FROM THE NORTHWEST LATER THU AND THU NIGHT WILL RESULT IN A MORE DEFINED GRADIENT WITH WIND SPEEDS EXCEEDING 15 KT AT TIMES. INCREASE IN SPEEDS WILL BUILD SEAS FROM 2 TO 3 FT WED TO 3 TO 5 FT BY THE END OF THE PERIOD. SEAS WILL STILL BE COMPRISED OF SOUTHEAST SWELL AND SOUTHERLY WIND WAVE BUT THE WIND WAVE WILL BECOME THE DOMINANT COMPONENT LATER THU. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...HIGH RIP CURRENT RISK UNTIL 8 PM EDT THIS EVENING FOR SCZ054. NC...HIGH RIP CURRENT RISK UNTIL 8 PM EDT THIS EVENING FOR NCZ106- 108-110. MARINE...NONE. && $$ NEAR TERM...RGZ SHORT TERM...III LONG TERM...III AVIATION...DL/RGZ
AREA FORECAST DISCUSSION
NWS RALEIGH NC
129 PM EDT SUN JUL 7 2013 .SYNOPSIS... A WEAKENING UPPER LEVEL LOW WILL PROGRESS EAST ACROSS THE MID- ATLANTIC TONIGHT. CYCLONIC FLOW ALOFT WILL PREVAIL OVER THE EASTERN UNITED STATES THROUGH MID WEEK...WITH AN UNSEASONABLY DEEP UPPER LEVEL TROUGH DIGGING SOUTHEAST IN THE MID-ATLANTIC BY FRIDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1025 AM SUNDAY... SOME VERY LIGHT SHOWERS HAVE DEVELOPED OVER THE SOUTHERN PIEDMONT AND SANDHILLS THIS MORNING. AS WITH YESTERDAY...THE HRRR HIGH RES CAM IS DOING A GOOD JOB SIMULATING THE CURRENT SHOWER ACTIVITY. THE LATEST RUN OF THE HRRR SHOWS AN INCREASE IN SHOWER COVERAGE...MAINLY IN THE NORTHEAST PIEDMONT AND SANDHILLS THROUGH THIS AFTERNOON... WITH THE MORE WIDESPREAD CONVECTION MOVING INTO THE NORTHWEST PIEDMONT LATE THIS AFT/EVE. 12Z UPPER AIR ANALYSES SHOW THE LOW WEST OF THE APPALACHIANS OVER IL/IN...WITH HIGH PRESSURE OFF THE CAROLINA COAST. WHILE CENTRAL NC IS RELATIVELY DRY...LOW LEVEL MOISTURE IS ADVECTING IN OFF THE GULF AHEAD OF THE LOW PRESSURE SYSTEM. AS THE UPPER LEVEL LOW MOVES EASTWARD TODAY SO WILL THE LOW/MID LEVEL MOISTURE AND SHOWERS/STORMS...CURRENTLY OVER THE MOUNTAINS. -KC PRECIPITATION CHANCES: SW FLOW ALOFT WILL STRENGTHEN FROM THE WEST TODAY...WITH AN INCREASING POTENTIAL FOR SMALL AMPLITUDE SHORTWAVES TRACKING NORTHEAST ACROSS WESTERN NC/VA THIS AFT/EVE...FOLLOWED BY ADDITIONAL DPVA WITHIN INCREASINGLY CYCLONIC FLOW ALOFT AS THE UPPER LEVEL LOW TRACKS INTO WESTERN PA BETWEEN 00-06Z TONIGHT. SHALLOW CONVERGENCE IN VICINITY OF A DEVELOPING PIEDMONT SFC TROUGH ASSOCIATED WITH SUBTLE HEIGHT FALLS IN ADVANCE OF THE UPPER LEVEL WAVE APPROACHING THE REGION THIS AFT/EVE WILL SERVE AS A POTENTIAL FOCUS FOR DIURNAL CONVECTION THIS AFTERNOON...FOLLOWED BY SOMEWHAT DEEPER CONVERGENCE TONIGHT AS THE LOW-LEVEL TROUGH SHARPENS IN RESPONSE TO STRONGER HEIGHT FALLS /CYCLONIC FLOW ALOFT/ OVER THE MID-ATLANTIC. SEASONAL BOUNDARY LAYER MOISTURE/DESTABILIZATION CAN BE EXPECTED AGAIN THIS AFTERNOON...WITH MLCAPE VALUES GENERALLY IN THE 1000-2000 J/KG RANGE ACROSS CENTRAL NC...THOUGH A WEST-EAST MID-LEVEL MOISTURE GRADIENT WILL PERSIST WITH DEEPER MOISTURE ACROSS THE FOOTHILLS/WESTERN PIEDMONT AND A DRIER AIRMASS ALOFT IN THE COASTAL PLAIN. WITH THE ABOVE IN MIND...EXPECT THE BEST CHANCE FOR CONVECTION THIS AFTERNOON AND EARLY EVENING WEST OF THE HWY 1 CORRIDOR IN VICINITY OF THE PIEDMONT SFC TROUGH AND IN CLOSER PROXIMITY TO SMALL AMPLITUDE SHORTWAVES/DEEPER MOISTURE IN STRENGTHENING SW FLOW ALOFT. WILL INDICATE PRECIP CHANCES RANGING FROM 20% EAST OF I-95 TO 50-60% IN THE FAR W/NW PIEDMONT. CONVECTION SHOULD PERSIST INTO TONIGHT ACROSS THE NORTHERN AND WESTERN PIEDMONT AS BETTER DPVA /STRONGER CYCLONIC FLOW ALOFT/ PROGRESSES INTO THE MID-ATLANTIC. TEMPERATURES: EXPECT HIGHS TODAY SIMILAR TO PREVIOUS DAYS WITH VERY SIMILAR REASONING...THOUGH PERHAPS SLIGHTLY WARMER GIVEN A MORE SOUTHWESTERLY LOW-LEVEL FLOW...ESP. ALONG AND EAST OF THE HWY 1 CORRIDOR...WITH HIGHS RANGING FROM THE MID 80S FAR NW PIEDMONT TO UPPER 80S AND LOWER 90S ELSEWHERE. LOWS TONIGHT SIMILAR TO PREVIOUS NIGHTS IN THE LOWER 70S. SEVERE THREAT: GIVEN DEEP LAYER SHEAR IN THE 25-35 KT RANGE ACROSS THE N/NW PIEDMONT IN THE PRESENCE OF MODERATE INSTABILITY (1000-2000 J/KG MLCAPE) AND DCAPE VALUES PROGGED AS HIGH AS 1000-1500 J/KG THIS AFT AND EARLY EVE...ANTICIPATE A POTENTIAL FOR DAMAGING WINDS... PRIMARILY WEST AND NW OF THE TRIANGLE. -VINCENT && .SHORT TERM /MONDAY/... AS OF 325 AM SUNDAY... ALTHOUGH THE AFOREMENTIONED UPPER LEVEL WAVE WILL TRACK EAST THROUGH THE MID-ATLANTIC EARLY MONDAY MORNING...CYCLONIC FLOW ALOFT AND LOW-LEVEL TROUGHING WILL PERSIST ACROSS THE AREA MONDAY AFT/EVE...WITH ADDITIONAL SHORTWAVE ENERGY ANTICIPATED TO DIG SOUTHEAST INTO NC/VA IN VICINITY OF PEAK HEATING. AS A RESULT... EXPECT ABOVE NORMAL CHANCES FOR CONVECTION...PRIMARILY DURING THE AFTERNOON AND EVENING HOURS...WITH HIGHS SIMILAR TO PREVIOUS DAYS... IN THE MID/UPPER 80S TO NEAR 90F. -VINCENT && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... AS OF 300 AM SUNDAY... NWP GUIDANCE IS IN GOOD AGREEMENT OF ANOTHER PERIOD OF UNSETTLED WEATHER WITH ABOVE NORMAL CHANCES OF PRECIPITATION FOR THE UPCOMING WEEK. THE EXTENDED RANGE WILL FEATURE A PERSISTENT AND STRONG RIDGE ACROSS THE SOUTHERN ROCKY MOUNTAINS AND A WEAKER BUT RELATIVELY STATIONARY AREA OF RIDGING OFF THE SOUTHEAST U.S. COAST. A SLOWLY WESTWARD ADVANCING CLOSED UPPER LOW MOVES WEST UNDER THE SUBTROPICAL ATLANTIC RIDGE REACHING FLORIDA ON TUESDAY AND THEN MOVES INTO THE EASTERN GULF OF MEXICO ON WEDNESDAY AND THURSDAY. A DIGGING SHORT WAVE TROUGH AND ASSOCIATED COLD FRONT DROPS INTO THE GREAT LAKES REGION ON WEDNESDAY REACHING THE MID ATLANTIC LATE THURSDAY AND THEN CLOSES OFF ON FRIDAY. THIS UPPER LOW DRIFTS SOUTHWEST INTO THE EASTERN TENNESSEE VALLEY BY SATURDAY. THE AIR MASS THROUGH THE PERIOD WILL REMAIN MOIST AND UNSTABLE WITH AN AXIS OF HIGH PRECIPITABLE WATER LINGERING ACROSS THE CAROLINAS AND VIRGINIA THROUGH MOST/ALL OF THE PERIOD. SENSIBLE WEATHER CONDITIONS WILL FEATURE AN UNSETTLED SUMMERTIME PATTERN WITH A HUMID AIR MASS AND THE THREAT OF MAINLY AFTERNOON AND EVENING CONVECTION EACH DAY. THE THREAT OF CONVECTION WILL BE GREATEST ON THURSDAY AND THURSDAY NIGHT WHEN NWP GUIDANCE IS IN GOOD AGREEMENT THAT A SHORTWAVE TROUGH AND COLD FRONT WILL APPROACH THE REGION. UNSETTLED WEATHER WITH ABOVE CLIMATOLOGY POPS WILL LIKELY PERSIST ON FRIDAY THROUGH SATURDAY ALTHOUGH THERE IS STILL SOME UNCERTAINTY ON WHERE THE SURFACE BOUNDARY AND MAIN MOISTURE FEED WILL SETUP. NEAR SEASONABLE TEMPERATURES ARE EXPECTED WITH HIGHS AROUND 90 WITH MORNING LOWS IN THE LOWER TO MID 70S. -BLAES && .AVIATION /18Z SUNDAY THROUGH THURSDAY/... AS OF 125 PM SUNDAY... 24-HR TAF PERIOD: CIGS HAVE BEEN BORDERLINE VFR/MVFR ALL DAY...BOUNCING BACK AND FORTH BETWEEN THE TWO...AND WILL LIKELY CONTINUE TO BE SO THROUGH MONDAY MORNING. LIGHT SHOWERS ARE OCCURRING AROUND KRDU...WITH HEAVIER SHOWERS AND POSSIBLE THUNDER MOVING INTO THE TRIAD (KINT AND KGSO) THIS AFTERNOON AND INTO THE OVERNIGHT HOURS. BEST CHANCE FOR LOW-END MVFR CIGS AT KINT AND KGSO DURING THE PRE-DAWN HOURS MONDAY...WITH THE POTENTIAL FOR A PERIOD OF BORDERLINE VFR/MVFR CIGS ELSEWHERE... ALTHOUGH CONFIDENCE IS LOW GIVEN THE DIFFERENCES IN MODEL GUIDANCE AT THIS TIME. THERE IS THE CHANCE FOR SHOWERS TO REDEVELOP ACROSS THE AREA MONDAY AFTERNOON/EVENING...BUT WILL LEAVE MENTION OUT OF TAFS FOR NOW. -KC LOOKING AHEAD: AVIATION CONDITIONS THROUGH MID/LATE WEEK WILL BE CHARACTERIZED BY AN ABOVE NORMAL CHANCE OF SHOWERS AND THUNDERSTORMS EACH DAY (PRIMARILY AFTERNOON AND EVENING HOURS) IN ASSOCIATION WITH CYCLONIC FLOW ALOFT AND AN ABOVE NORMAL CHANCE FOR MVFR/IFR STRATUS OR FOG EACH MORNING (PRIMARILY 07-13Z) IN ASSOCIATION WITH A PERSISTENT MOIST SOUTHERLY RETURN FLOW. -VINCENT && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...VINCENT NEAR TERM...KC/VINCENT SHORT TERM...VINCENT LONG TERM...BLAES AVIATION...KC/VINCENT
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1027 AM EDT SUN JUL 7 2013 .SYNOPSIS... A WEAKENING UPPER LEVEL LOW WILL TRACK INTO THE OHIO VALLEY THIS AFTERNOON...PROGRESSING EAST ACROSS THE MID-ATLANTIC TONIGHT. CYCLONIC FLOW ALOFT WILL PREVAIL OVER THE EASTERN UNITED STATES THROUGH MID WEEK...WITH AN UNSEASONABLY DEEP UPPER LEVEL TROUGH DIGGING SOUTHEAST IN THE MID-ATLANTIC BY FRIDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1025 AM SUNDAY... SOME VERY LIGHT SHOWERS HAVE DEVELOPED OVER THE SOUTHERN PIEDMONT AND SANDHILLS THIS MORNING. AS WITH YESTERDAY...THE HRRR HIGH RES CAM IS DOING A GOOD JOB SIMULATING THE CURRENT SHOWER ACTIVITY. THE LATEST RUN OF THE HRRR SHOWS AN INCREASE IN SHOWER COVERAGE...MAINLY IN THE NORTHEAST PIEDMONT AND SANDHILLS THROUGH THIS AFTERNOON... WITH THE MORE WIDESPREAD CONVECTION MOVING INTO THE NORTHWEST PIEDMONT LATE THIS AFT/EVE. 12Z UPPER AIR ANALYSES SHOW THE LOW WEST OF THE APPALACHIANS OVER IL/IN...WITH HIGH PRESSURE OFF THE CAROLINA COAST. WHILE CENTRAL NC IS RELATIVELY DRY...LOW LEVEL MOISTURE IS ADVECTING IN OFF THE GULF AHEAD OF THE LOW PRESSURE SYSTEM. AS THE UPPER LEVEL LOW MOVES EASTWARD TODAY SO WILL THE LOW/MID LEVEL MOISTURE AND SHOWERS/STORMS...CURRENTLY OVER THE MOUNTAINS. -KC PRECIPITATION CHANCES: SW FLOW ALOFT WILL STRENGTHEN FROM THE WEST TODAY...WITH AN INCREASING POTENTIAL FOR SMALL AMPLITUDE SHORTWAVES TRACKING NORTHEAST ACROSS WESTERN NC/VA THIS AFT/EVE...FOLLOWED BY ADDITIONAL DPVA WITHIN INCREASINGLY CYCLONIC FLOW ALOFT AS THE UPPER LEVEL LOW TRACKS INTO WESTERN PA BETWEEN 00-06Z TONIGHT. SHALLOW CONVERGENCE IN VICINITY OF A DEVELOPING PIEDMONT SFC TROUGH ASSOCIATED WITH SUBTLE HEIGHT FALLS IN ADVANCE OF THE UPPER LEVEL WAVE APPROACHING THE REGION THIS AFT/EVE WILL SERVE AS A POTENTIAL FOCUS FOR DIURNAL CONVECTION THIS AFTERNOON...FOLLOWED BY SOMEWHAT DEEPER CONVERGENCE TONIGHT AS THE LOW-LEVEL TROUGH SHARPENS IN RESPONSE TO STRONGER HEIGHT FALLS /CYCLONIC FLOW ALOFT/ OVER THE MID-ATLANTIC. SEASONAL BOUNDARY LAYER MOISTURE/DESTABILIZATION CAN BE EXPECTED AGAIN THIS AFTERNOON...WITH MLCAPE VALUES GENERALLY IN THE 1000-2000 J/KG RANGE ACROSS CENTRAL NC...THOUGH A WEST-EAST MID-LEVEL MOISTURE GRADIENT WILL PERSIST WITH DEEPER MOISTURE ACROSS THE FOOTHILLS/WESTERN PIEDMONT AND A DRIER AIRMASS ALOFT IN THE COASTAL PLAIN. WITH THE ABOVE IN MIND...EXPECT THE BEST CHANCE FOR CONVECTION THIS AFTERNOON AND EARLY EVENING WEST OF THE HWY 1 CORRIDOR IN VICINITY OF THE PIEDMONT SFC TROUGH AND IN CLOSER PROXIMITY TO SMALL AMPLITUDE SHORTWAVES/DEEPER MOISTURE IN STRENGTHENING SW FLOW ALOFT. WILL INDICATE PRECIP CHANCES RANGING FROM 20% EAST OF I-95 TO 50-60% IN THE FAR W/NW PIEDMONT. CONVECTION SHOULD PERSIST INTO TONIGHT ACROSS THE NORTHERN AND WESTERN PIEDMONT AS BETTER DPVA /STRONGER CYCLONIC FLOW ALOFT/ PROGRESSES INTO THE MID-ATLANTIC. TEMPERATURES: EXPECT HIGHS TODAY SIMILAR TO PREVIOUS DAYS WITH VERY SIMILAR REASONING...THOUGH PERHAPS SLIGHTLY WARMER GIVEN A MORE SOUTHWESTERLY LOW-LEVEL FLOW...ESP. ALONG AND EAST OF THE HWY 1 CORRIDOR...WITH HIGHS RANGING FROM THE MID 80S FAR NW PIEDMONT TO UPPER 80S AND LOWER 90S ELSEWHERE. LOWS TONIGHT SIMILAR TO PREVIOUS NIGHTS IN THE LOWER 70S. SEVERE THREAT: GIVEN DEEP LAYER SHEAR IN THE 25-35 KT RANGE ACROSS THE N/NW PIEDMONT IN THE PRESENCE OF MODERATE INSTABILITY (1000-2000 J/KG MLCAPE) AND DCAPE VALUES PROGGED AS HIGH AS 1000-1500 J/KG THIS AFT AND EARLY EVE...ANTICIPATE A POTENTIAL FOR DAMAGING WINDS... PRIMARILY WEST AND NW OF THE TRIANGLE. -VINCENT && .SHORT TERM /MONDAY/... AS OF 325 AM SUNDAY... ALTHOUGH THE AFOREMENTIONED UPPER LEVEL WAVE WILL TRACK EAST THROUGH THE MID-ATLANTIC EARLY MONDAY MORNING...CYCLONIC FLOW ALOFT AND LOW-LEVEL TROUGHING WILL PERSIST ACROSS THE AREA MONDAY AFT/EVE...WITH ADDITIONAL SHORTWAVE ENERGY ANTICIPATED TO DIG SOUTHEAST INTO NC/VA IN VICINITY OF PEAK HEATING. AS A RESULT... EXPECT ABOVE NORMAL CHANCES FOR CONVECTION...PRIMARILY DURING THE AFTERNOON AND EVENING HOURS...WITH HIGHS SIMILAR TO PREVIOUS DAYS... IN THE MID/UPPER 80S TO NEAR 90F. -VINCENT && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... AS OF 300 AM SUNDAY... NWP GUIDANCE IS IN GOOD AGREEMENT OF ANOTHER PERIOD OF UNSETTLED WEATHER WITH ABOVE NORMAL CHANCES OF PRECIPITATION FOR THE UPCOMING WEEK. THE EXTENDED RANGE WILL FEATURE A PERSISTENT AND STRONG RIDGE ACROSS THE SOUTHERN ROCKY MOUNTAINS AND A WEAKER BUT RELATIVELY STATIONARY AREA OF RIDGING OFF THE SOUTHEAST U.S. COAST. A SLOWLY WESTWARD ADVANCING CLOSED UPPER LOW MOVES WEST UNDER THE SUBTROPICAL ATLANTIC RIDGE REACHING FLORIDA ON TUESDAY AND THEN MOVES INTO THE EASTERN GULF OF MEXICO ON WEDNESDAY AND THURSDAY. A DIGGING SHORT WAVE TROUGH AND ASSOCIATED COLD FRONT DROPS INTO THE GREAT LAKES REGION ON WEDNESDAY REACHING THE MID ATLANTIC LATE THURSDAY AND THEN CLOSES OFF ON FRIDAY. THIS UPPER LOW DRIFTS SOUTHWEST INTO THE EASTERN TENNESSEE VALLEY BY SATURDAY. THE AIR MASS THROUGH THE PERIOD WILL REMAIN MOIST AND UNSTABLE WITH AN AXIS OF HIGH PRECIPITABLE WATER LINGERING ACROSS THE CAROLINAS AND VIRGINIA THROUGH MOST/ALL OF THE PERIOD. SENSIBLE WEATHER CONDITIONS WILL FEATURE AN UNSETTLED SUMMERTIME PATTERN WITH A HUMID AIR MASS AND THE THREAT OF MAINLY AFTERNOON AND EVENING CONVECTION EACH DAY. THE THREAT OF CONVECTION WILL BE GREATEST ON THURSDAY AND THURSDAY NIGHT WHEN NWP GUIDANCE IS IN GOOD AGREEMENT THAT A SHORTWAVE TROUGH AND COLD FRONT WILL APPROACH THE REGION. UNSETTLED WEATHER WITH ABOVE CLIMATOLOGY POPS WILL LIKELY PERSIST ON FRIDAY THROUGH SATURDAY ALTHOUGH THERE IS STILL SOME UNCERTAINTY ON WHERE THE SURFACE BOUNDARY AND MAIN MOISTURE FEED WILL SETUP. NEAR SEASONABLE TEMPERATURES ARE EXPECTED WITH HIGHS AROUND 90 WITH MORNING LOWS IN THE LOWER TO MID 70S. -BLAES && .AVIATION /12Z SUNDAY THROUGH THURSDAY/... AS OF 700 AM SUNDAY... 24-HR TAF PERIOD: SUB-VFR STRATUS AT THE INT/GSO TERMINALS WILL GRADUALLY LIFT AND SCATTER OUT TO VFR BY 13-15Z. EXPECT ISOLD/SCT CONVECTION THIS AFTERNOON THROUGH THIS EVENING (16-04Z)...WITH THE BEST CHANCE AT THE INT/GSO TERMINALS. A CHANCE OF SHOWERS WILL PERSIST OVERNIGHT/ MONDAY MORNING AS AN UPPER LEVEL DISTURBANCE TRACKS EAST THROUGH THE OH VALLEY INTO THE MID-ATLANTIC...ALONG WITH A POTENTIAL FOR MVFR/IFR CEILINGS BY 08-12Z MON. LOOKING AHEAD: AVIATION CONDITIONS THROUGH MID/LATE WEEK WILL BE CHARACTERIZED BY AN ABOVE NORMAL CHANCE OF SHOWERS AND THUNDERSTORMS EACH DAY (PRIMARILY AFTERNOON AND EVENING HOURS) IN ASSOCIATION WITH CYCLONIC FLOW ALOFT AND AN ABOVE NORMAL CHANCE FOR MVFR/IFR STRATUS OR FOG EACH MORNING (PRIMARILY 07-13Z) IN ASSOCIATION WITH A PERSISTENT MOIST SOUTHERLY RETURN FLOW. -VINCENT && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...VINCENT NEAR TERM...KC/VINCENT SHORT TERM...VINCENT LONG TERM...BLAES AVIATION...VINCENT
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1013 PM CDT MON JUL 8 2013 .UPDATE... ISSUED AT 1013 PM CDT MON JUL 8 2013 UPDATED THE FORECAST TO EXTEND THE SEVERE THUNDERSTORM WATCH EAST INTO THE JAMES RIVER VALLEY. MCS OVER WEST CENTRAL NORTH DAKOTA DEVELOPED INTO AN MCV IN THE LAST HOUR OR TWO. THE LEADING EDGE OF THIS ACTIVITY HAS BEEN PRODUCING WIDESPREAD WIND GUSTS UP TO 60 MPH. THIS ACTIVITY WILL CONTINUE TO PUSH EAST INTO THE JAMES RIVER VALLEY AFTER MIDNIGHT. ANOTHER BOW ECHO IS PUSHING EAST ACROSS SOUTHWESTERN NORTH DAKOTA. ITS STORM MOTION HAS BEEN EAST-SOUTHEAST AND WILL LIKELY CONTINUE TO PUSH INTO SOUTH DAKOTA DURING THE NEXT FEW HOURS. THE UPDATED PRODUCTS HAVE BEEN SENT. UPDATE ISSUED AT 703 PM CDT MON JUL 8 2013 UPDATED THE FORECAST TO ADD SEVERE THUNDERSTORM WATCH 402 FOR AREAS WEST OF HIGHWAY 83. ONGOING CONVECTION OVER EAST-CENTRAL MONTANA SHOULD CONTINUE TO MOVE EAST-SOUTHEAST INTO SOUTHWESTERN NORTH DAKOTA EARLY THIS EVENING. THIS ACTIVITY IS CONGEALING INTO AN MCS AND IS MOVING INTO A FAVORABLE ENVIRONMENT FOR MCS MAINTENANCE (SURFACE BASED CAPE AROUND 2000 J/KG PER LATEST LAPS ANALYSIS). THIS INITIAL CONVECTIVE ACTIVITY PROMPTED SPC TO ISSUE A SEVERE THUNDERSTORM WATCH FOR AREAS WEST OF HIGHWAY 83 UNTIL MIDNIGHT CDT. SHORT-RANGE MESOSCALE MODELS CONTINUE TO PROG THE PRIMARY LINE OF CONVECTION (CURRENTLY EXTENDING FROM GLASGOW TO BILLINGS) TO PUSH INTO WESTERN NORTH DAKOTA AROUND 03Z...AND SWEEP ACROSS THE CWA TONIGHT. THE FLY IN THE OINTMENT IS JUST HOW MUCH INSTABILITY THE INITIAL MCS CHEWS UP BEFORE THE PRIMARY LINE SWINGS THROUGH. STILL WILL MAINTAIN SEVERE WORDING PAST MIDNIGHT FOR CENTRAL NORTH DAKOTA. HOWEVER...WILL CONTINUE TO MONITOR EVENING TRENDS AND MAKE ANY ADJUSTMENTS AS NEEDED. THE UPDATED GRIDDED AND TEXT PRODUCTS HAVE BEEN SENT. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 341 PM CDT MON JUL 8 2013 THE MAIN FORECAST ISSUE DURING THE SHORT TERM IS STORM COVERAGE/TIMING/SEVERITY THROUGH TONIGHT. SCATTERED STORMS ARE EXPECTED TO DEVELOP AND/OR MOVE INTO THE WEST LATE THIS AFTERNOON. MORE FAVORABLE DEEP LAYER SHEAR IS CONFINED TO THE WEST THROUGH LATE AFTERNOON. SOME ISOLATED SEVERE STORMS ARE POSSIBLE...WITH LARGE HAIL THE MAIN THREAT. THE HRRR IS STILL FOCUSING ON THE SOUTHWEST FOR INITIATION...WHILE THE 12Z WRF FOCUSES ON A FRONT STRETCHING FROM WEST CENTRAL INTO NORTH CENTRAL NORTH DAKOTA. WILL CONTINUE TO MONITOR CLOSELY FOR INITIATION. AN INTENSE SUPERCELL IS MOVING THROUGH NORTHEAST MONTANA...AND WOULD IMPACT THE FORECAST AREA AFTER 00Z IF IT HOLDS TOGETHER. A BIGGER CONCERN WILL BE A THUNDERSTORM COMPLEX THAT WILL LIKELY TRACK FROM WEST TO EAST ACROSS THE FORECAST AREA AFTER AROUND 9 PM CDT. DAMAGING STRAIGHT LINE WINDS WILL BE THE BIGGEST THREAT. FAST STORM MOTIONS SHOULD PRECLUDE WIDESPREAD FLASH FLOODING. A MULTI- MEDIA WEATHER BRIEFING HAS BEEN POSTED AT WWW.WEATHER.GOV/BIS. THE SEVERE THREAT MAY PERSIST AFTER MIDNIGHT TONIGHT BEFORE STORMS WEAKEN. ADDITIONAL NON-SEVERE STORMS WILL BE LIKELY THROUGH AT LEAST MIDDAY TUESDAY. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 341 PM CDT MON JUL 8 2013 MAIN HIGHLIGHT FOR THE LONG TERM IS SHORTWAVE TROUGH AND ASSOCIATED COLD FRONT ENTERING NORTHERN PLAINS THURSDAY/FRIDAY. THE PERSISTENT HIGH AMPLITUDE RIDGING TO THE WEST WILL CONTINUE TO BE BOMBARDED BY SHORTWAVE TROUGHS DIVING DOWN OUT OF WESTERN CANADA. THIS WILL FORCE THE RIDGE TO TRANSLATE EASTWARD OVER THE CENTRAL STATES. THIS WILL IN TURN ALLOW NORTH DAKOTA TO BE INFLUENCED BY SOUTHWESTERLY FLOW AND LEE CYCLOGENESIS. BOTH THE 12 UTC ECMWF AND THE 12 UTC GFS BOTH HAVE A SHORTWAVE TROUGH DRAPED ACROSS THE NORTHERN PLAINS AND SURFACE LOW OVER NORTHWESTERN SOUTH DAKOTA EARLY FRIDAY MORNING. THIS WILL ALLOW FOR MOIST SOUTHERLY FLOW AHEAD OF THE COLD FRONT. WITH INCREASING MOISTURE...SURFACE LOW PRESSURE...AND UPPER LEVEL DIFFLUENCE WIDESPREAD THUNDERSTORM DEVELOPMENT IS POSSIBLE FRIDAY AFTERNOON AND EVENING. IN ADDITION TO THOSE INGREDIENTS THE 12 UTC ECMWF IS FORECASTING 50+ KNOTS OF 0-6 KM SHEAR...2000+ MUCAPE...AND DEW POINTS IN THE MID TO UPPER 60S. IF THIS VERIFIES...SEVERE WEATHER IS POSSIBLE FRIDAY AFTERNOON AND EVENING. OTHERWISE...THE EXTENDED PERIOD LOOKS ACTIVE WITH CHANCES FOR PRECIP THROUGHOUT THE PERIOD AS SHORTWAVES RIDE ALONG THE NORTHERN PERIPHERY OF THE RIDGE TO OUR SOUTH. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING) ISSUED AT 703 PM CDT MON JUL 8 2013 THE MAIN FOCUS THROUGH THE TAF PERIOD IS THUNDERSTORMS. OTHERWISE...EXPECT VFR CONDITIONS. SCATTERED STORMS ARE EXPECTED THIS EVENING...BUT TOUGH TO PINPOINT FAVORED AREA FOR DEVELOPMENT AND TIMING. LATER TONIGHT...AFTER 02Z...ENHANCED WINDS WILL BE POSSIBLE WITH FAST MOVING LINES OF THUNDERSTORMS. ALTHOUGH THESE SEVERE WEATHER ELEMENTS WILL BE POSSIBLE..TOO UNCERTAIN IN TIMING TO INCLUDE IN TAF FORECAST. AVIATION PLANNERS SHOULD ANTICIPATE MULTIPLE LINES OF THUNDERSTORMS MOVING WEST TO EAST ACROSS THE STATE AFTER 02Z. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...TM SHORT TERM...RPK LONG TERM...AJ AVIATION...TM
AREA FORECAST DISCUSSION
NWS BISMARCK ND
703 PM CDT MON JUL 8 2013 .UPDATE... ISSUED AT 703 PM CDT MON JUL 8 2013 UPDATED THE FORECAST TO ADD SEVERE THUNDERSTORM WATCH 402 FOR AREAS WEST OF HIGHWAY 83. ONGOING CONVECTION OVER EAST-CENTRAL MONTANA SHOULD CONTINUE TO MOVE EAST-SOUTHEAST INTO SOUTHWESTERN NORTH DAKOTA EARLY THIS EVENING. THIS ACTIVITY IS CONGEALING INTO AN MCS AND IS MOVING INTO A FAVORABLE ENVIRONMENT FOR MCS MAINTENANCE (SURFACE BASED CAPE AROUND 2000 J/KG PER LATEST LAPS ANALYSIS). THIS INITIAL CONVECTIVE ACTIVITY PROMPTED SPC TO ISSUE A SEVERE THUNDERSTORM WATCH FOR AREAS WEST OF HIGHWAY 83 UNTIL MIDNIGHT CDT. SHORT-RANGE MESOSCALE MODELS CONTINUE TO PROG THE PRIMARY LINE OF CONVECTION (CURRENTLY EXTENDING FROM GLASGOW TO BILLINGS) TO PUSH INTO WESTERN NORTH DAKOTA AROUND 03Z...AND SWEEP ACROSS THE CWA TONIGHT. THE FLY IN THE OINTMENT IS JUST HOW MUCH INSTABILITY THE INITIAL MCS CHEWS UP BEFORE THE PRIMARY LINE SWINGS THROUGH. STILL WILL MAINTAIN SEVERE WORDING PAST MIDNIGHT FOR CENTRAL NORTH DAKOTA. HOWEVER...WILL CONTINUE TO MONITOR EVENING TRENDS AND MAKE ANY ADJUSTMENTS AS NEEDED. THE UPDATED GRIDDED AND TEXT PRODUCTS HAVE BEEN SENT. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 341 PM CDT MON JUL 8 2013 THE MAIN FORECAST ISSUE DURING THE SHORT TERM IS STORM COVERAGE/TIMING/SEVERITY THROUGH TONIGHT. SCATTERED STORMS ARE EXPECTED TO DEVELOP AND/OR MOVE INTO THE WEST LATE THIS AFTERNOON. MORE FAVORABLE DEEP LAYER SHEAR IS CONFINED TO THE WEST THROUGH LATE AFTERNOON. SOME ISOLATED SEVERE STORMS ARE POSSIBLE...WITH LARGE HAIL THE MAIN THREAT. THE HRRR IS STILL FOCUSING ON THE SOUTHWEST FOR INITIATION...WHILE THE 12Z WRF FOCUSES ON A FRONT STRETCHING FROM WEST CENTRAL INTO NORTH CENTRAL NORTH DAKOTA. WILL CONTINUE TO MONITOR CLOSELY FOR INITIATION. AN INTENSE SUPERCELL IS MOVING THROUGH NORTHEAST MONTANA...AND WOULD IMPACT THE FORECAST AREA AFTER 00Z IF IT HOLDS TOGETHER. A BIGGER CONCERN WILL BE A THUNDERSTORM COMPLEX THAT WILL LIKELY TRACK FROM WEST TO EAST ACROSS THE FORECAST AREA AFTER AROUND 9 PM CDT. DAMAGING STRAIGHT LINE WINDS WILL BE THE BIGGEST THREAT. FAST STORM MOTIONS SHOULD PRECLUDE WIDESPREAD FLASH FLOODING. A MULTI- MEDIA WEATHER BRIEFING HAS BEEN POSTED AT WWW.WEATHER.GOV/BIS. THE SEVERE THREAT MAY PERSIST AFTER MIDNIGHT TONIGHT BEFORE STORMS WEAKEN. ADDITIONAL NON-SEVERE STORMS WILL BE LIKELY THROUGH AT LEAST MIDDAY TUESDAY. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 341 PM CDT MON JUL 8 2013 MAIN HIGHLIGHT FOR THE LONG TERM IS SHORTWAVE TROUGH AND ASSOCIATED COLD FRONT ENTERING NORTHERN PLAINS THURSDAY/FRIDAY. THE PERSISTENT HIGH AMPLITUDE RIDGING TO THE WEST WILL CONTINUE TO BE BOMBARDED BY SHORTWAVE TROUGHS DIVING DOWN OUT OF WESTERN CANADA. THIS WILL FORCE THE RIDGE TO TRANSLATE EASTWARD OVER THE CENTRAL STATES. THIS WILL IN TURN ALLOW NORTH DAKOTA TO BE INFLUENCED BY SOUTHWESTERLY FLOW AND LEE CYCLOGENESIS. BOTH THE 12 UTC ECMWF AND THE 12 UTC GFS BOTH HAVE A SHORTWAVE TROUGH DRAPED ACROSS THE NORTHERN PLAINS AND SURFACE LOW OVER NORTHWESTERN SOUTH DAKOTA EARLY FRIDAY MORNING. THIS WILL ALLOW FOR MOIST SOUTHERLY FLOW AHEAD OF THE COLD FRONT. WITH INCREASING MOISTURE...SURFACE LOW PRESSURE...AND UPPER LEVEL DIFFLUENCE WIDESPREAD THUNDERSTORM DEVELOPMENT IS POSSIBLE FRIDAY AFTERNOON AND EVENING. IN ADDITION TO THOSE INGREDIENTS THE 12 UTC ECMWF IS FORECASTING 50+ KNOTS OF 0-6 KM SHEAR...2000+ MUCAPE...AND DEW POINTS IN THE MID TO UPPER 60S. IF THIS VERIFIES...SEVERE WEATHER IS POSSIBLE FRIDAY AFTERNOON AND EVENING. OTHERWISE...THE EXTENDED PERIOD LOOKS ACTIVE WITH CHANCES FOR PRECIP THROUGHOUT THE PERIOD AS SHORTWAVES RIDE ALONG THE NORTHERN PERIPHERY OF THE RIDGE TO OUR SOUTH. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING) ISSUED AT 703 PM CDT MON JUL 8 2013 THE MAIN FOCUS THROUGH THE TAF PERIOD IS THUNDERSTORMS. OTHERWISE...EXPECT VFR CONDITIONS. SCATTERED STORMS ARE EXPECTED THIS EVENING...BUT TOUGH TO PINPOINT FAVORED AREA FOR DEVELOPMENT AND TIMING. LATER TONIGHT...AFTER 02Z...ENHANCED WINDS WILL BE POSSIBLE WITH FAST MOVING LINES OF THUNDERSTORMS. ALTHOUGH THESE SEVERE WEATHER ELEMENTS WILL BE POSSIBLE..TOO UNCERTAIN IN TIMING TO INCLUDE IN TAF FORECAST. AVIATION PLANNERS SHOULD ANTICIPATE MULTIPLE LINES OF THUNDERSTORMS MOVING WEST TO EAST ACROSS THE STATE AFTER 02Z. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...TM SHORT TERM...RPK LONG TERM...AJ AVIATION...TM
AREA FORECAST DISCUSSION
NWS BISMARCK ND
142 PM CDT SUN JUL 7 2013 .UPDATE... ISSUED AT 111 PM CDT SUN JUL 7 2013 UPDATE FOR ADDITIONAL ADJUSTMENTS TO POPS THROUGH TONIGHT...AND MIDDAY TEMP TRENDS. CLOUDS HAVE INHIBITED TEMPS AT MANY LOCATIONS...ESPECIALLY THE FAT SOUTH...BUT PARTIAL CLEARING IS EXPECTED AS THE AFTERNOON PROGRESSES. A FEW STRONG STORMS ARE POSSIBLE SOUTHWEST LATE THIS AFTERNOON AND EVENING IN THE AREA OF GREATEST INSOLATION. THE LATEST HRRR AND 12 WRF ALL DEVELOP CONVECTION AROUND 21Z-22Z. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 345 AM CDT SUN JUL 7 2013 EARLY MORNING SURFACE ANALYSIS PLACED A WEAK SURFACE TROUGH ACROSS EASTERN NORTH DAKOTA. THE TROUGH WAS THE FOCUS FOR ISOLATED THUNDERSTORMS EARLIER THIS MORNING...BUT THEY HAVE SINCE DIMINISHED. THE TROUGH WILL MOVE SLOWLY EAST THIS MORNING...TAKING THE THREAT OF ADDITIONAL THUNDERSTORMS WITH IT. THE NEXT CONCERN WILL BE SHOWERS / THUNDERSTORMS IN EASTERN MONTANA WHICH HAVE BEEN MAKING STEADY PROGRESS TOWARDS WESTERN NORTH DAKOTA EARLY THIS MORNING. THE STORMS IN EASTERN MONTANA ARE IN PART BEING DRIVEN BY A SHORT WAVE WHICH IS EXPECTED TO MOVE INTO WESTERN NORTH DAKOTA THIS MORNING...AND INTO CENTRAL NORTH DAKOTA THIS AFTERNOON. VARIOUS MODEL SOLUTIONS (NAM / RAP / GFS / 4KM WRF) ALL SUGGEST THERE WILL BE A CHANCE OF PRECIPITATION AS THE WAVE MOVES ACROSS THE FORECAST AREA. WHERE THEY DIFFER TO SOME EXTENT IS IN THEIR COVERAGE OF PRECIPITATION. WILL HOLD ONTO CHANCE POPS ACROSS MOST OF THE FORECAST AREA TODAY / THIS EVENING WITH THE HIGHER POPS IN THE WEST. THE LATEST DAY 1 OUTLOOK PLACES THE SOUTHWEST PART OF THE STATE IN A SLIGHT RISK...WHICH APPEARS REASONABLE SINCE THAT AREA IS FORECAST TO HAVE THE GREATEST INSTABILITY THIS AFTERNOON / EVENING WITH MLCAPE VALUES OF UP TO 1500 J/KG. CONFIDENCE IN THUNDERSTORM COVERAGE LATE TONIGHT INTO EARLY MONDAY MORNING DECREASES TO SOME EXTENT AS THE INITIAL WAVE MOVES EAST. CONFLICTING SIGNALS ARE SHOWN IN THE MODEL SOLUTIONS WITH SOME SUGGESTING LIMITED THUNDERSTORM COVERAGE OVERNIGHT...WHILE OTHERS BRING ADDITIONAL THUNDERSTORMS INTO WESTERN NORTH DAKOTA FROM EASTERN MONTANA. WILL HOLD ONTO CHANCE POPS IN THE CENTRAL AND WEST...WITH SLIGHT CHANCES IN THE EAST WHERE CONFIDENCE IN ADDITIONAL CONVECTION IS LOWER. CLOUDS FROM SHOWERS / THUNDERSTORMS COULD INFLUENCE TEMPERATURES TODAY. WILL FOLLOW A BLEND OF GUIDANCE VALUES WITH HIGHS NEAR 80 NORTH...AND LOWER TO MID 80S SOUTH. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 345 AM CDT SUN JUL 7 2013 MODELS AGREE IN A SOUTHWEST FLOW ALOFT FROM THE NORTHWEST US TO THE NORTHERN PLAINS EARLY IN THE PERIOD. AN ACTIVE SHORTWAVE PATTERN WILL BRING SEVERAL SHORTWAVES THROUGH THE REGION BRINGING SOME WIDESPREAD SHOWERS AND THUNDERSTORMS TO THE REGION MONDAY NIGHT AND TUESDAY. THIS WILL BE FOLLOWED BY A BREAK IN THE PRECIPITATION CHANCES WEDNESDAY AND THURSDAY AS AN H500 RIDGE POSITIONS ITSELF OVER THE NORTHERN PLAINS. AS THIS FEATURE MOVES EAST BY NEXT WEEKEND WILL SEE AT LEAST A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS RETURN FOR FRIDAY AND SATURDAY. THE PRIMARY FOCUS WILL BE MONDAY NIGHT. BY MONDAY AFTERNOON LOW PRESSURE WILL DEVELOP ACROSS MONTANA BRINGING A EASTERLY WIND FLOW ACROSS WEST AND CENTRAL NORTH DAKOTA. THIS WILL PULL ABUNDANT MOISTURE INTO THE REGION. MODEL SOUNDINGS FORECAST PWATS BETWEEN 1.5 AND 1.75 INCHES...OR ROUGHLY 2 STANDARD DEVIATIONS ABOVE NORMAL IF CORRECT. WITH ABUNDANT MOISTURE WILL MENTION HEAVY RAIN IN THE HWO ALONG WITH SLIGHT CHANCE SEVERE FROM SPC MONDAY NIGHT. THUNDERSTORMS WILL END TUESDAY FOLLOWED BY THE DRY WEATHER WEDNESDAYS AND THURSDAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 111 PM CDT SUN JUL 7 2013 WESTERN NORTH DAKOTA WILL BE THE PRIMARY FOCUS FOR SCATTERED THUNDERSTORMS LATER THIS AFTERNOON AND EVENING...MAINLY IMPACTING KDIK/KISN. STORMS ARE EXPECTED TO BE TOO SCATTERED IN NATURE TO WARRANT MORE THAN VCTS GROUPS AT THIS TIME. OTHER THAN BRIEF MVFR VSBYS IN THE MORE INTENSE STORMS...EXPECT VFR CONDITIONS. ADDITIONAL SHOWERS AND ISOLATED THUNDERSTORMS ARE POSSIBLE TOWARD DAYBREAK AT KMOT...THEN BY MID MORNING AT KDIK/KBIS/KJMS. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE/AVIATION...RP KINNEY SHORT TERM...CK LONG TERM...WAA
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1043 AM CDT SUN JUL 7 2013 .UPDATE... ISSUED AT 958 AM CDT SUN JUL 7 2013 UPDATE TO SCALE BACK POPS WEST AND CENTRAL THIS AFTERNOON AND EVENING...AS COVERAGE OF STORMS NOW EXPECTED TO BE LESS BASED ON RECENT HI-RES MODEL RUNS. ISOLATED SEVERE STORMS WILL BE POSSIBLE...MAINLY IN THE EARLY EVENING ACROSS THE FAR SOUTHWEST. ANOTHER SHORT WAVE MAY GLANCE NORTHERN COUNTIES OVERNIGHT WITH ADDITIONAL STORMS...BUT CONFIDENCE IN THIS SCENARIO IS LOW. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 345 AM CDT SUN JUL 7 2013 EARLY MORNING SURFACE ANALYSIS PLACED A WEAK SURFACE TROUGH ACROSS EASTERN NORTH DAKOTA. THE TROUGH WAS THE FOCUS FOR ISOLATED THUNDERSTORMS EARLIER THIS MORNING...BUT THEY HAVE SINCE DIMINISHED. THE TROUGH WILL MOVE SLOWLY EAST THIS MORNING...TAKING THE THREAT OF ADDITIONAL THUNDERSTORMS WITH IT. THE NEXT CONCERN WILL BE SHOWERS / THUNDERSTORMS IN EASTERN MONTANA WHICH HAVE BEEN MAKING STEADY PROGRESS TOWARDS WESTERN NORTH DAKOTA EARLY THIS MORNING. THE STORMS IN EASTERN MONTANA ARE IN PART BEING DRIVEN BY A SHORT WAVE WHICH IS EXPECTED TO MOVE INTO WESTERN NORTH DAKOTA THIS MORNING...AND INTO CENTRAL NORTH DAKOTA THIS AFTERNOON. VARIOUS MODEL SOLUTIONS (NAM / RAP / GFS / 4KM WRF) ALL SUGGEST THERE WILL BE A CHANCE OF PRECIPITATION AS THE WAVE MOVES ACROSS THE FORECAST AREA. WHERE THEY DIFFER TO SOME EXTENT IS IN THEIR COVERAGE OF PRECIPITATION. WILL HOLD ONTO CHANCE POPS ACROSS MOST OF THE FORECAST AREA TODAY / THIS EVENING WITH THE HIGHER POPS IN THE WEST. THE LATEST DAY 1 OUTLOOK PLACES THE SOUTHWEST PART OF THE STATE IN A SLIGHT RISK...WHICH APPEARS REASONABLE SINCE THAT AREA IS FORECAST TO HAVE THE GREATEST INSTABILITY THIS AFTERNOON / EVENING WITH MLCAPE VALUES OF UP TO 1500 J/KG. CONFIDENCE IN THUNDERSTORM COVERAGE LATE TONIGHT INTO EARLY MONDAY MORNING DECREASES TO SOME EXTENT AS THE INITIAL WAVE MOVES EAST. CONFLICTING SIGNALS ARE SHOWN IN THE MODEL SOLUTIONS WITH SOME SUGGESTING LIMITED THUNDERSTORM COVERAGE OVERNIGHT...WHILE OTHERS BRING ADDITIONAL THUNDERSTORMS INTO WESTERN NORTH DAKOTA FROM EASTERN MONTANA. WILL HOLD ONTO CHANCE POPS IN THE CENTRAL AND WEST...WITH SLIGHT CHANCES IN THE EAST WHERE CONFIDENCE IN ADDITIONAL CONVECTION IS LOWER. CLOUDS FROM SHOWERS / THUNDERSTORMS COULD INFLUENCE TEMPERATURES TODAY. WILL FOLLOW A BLEND OF GUIDANCE VALUES WITH HIGHS NEAR 80 NORTH...AND LOWER TO MID 80S SOUTH. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 345 AM CDT SUN JUL 7 2013 MODELS AGREE IN A SOUTHWEST FLOW ALOFT FROM THE NORTHWEST US TO THE NORTHERN PLAINS EARLY IN THE PERIOD. AN ACTIVE SHORTWAVE PATTERN WILL BRING SEVERAL SHORTWAVES THROUGH THE REGION BRINGING SOME WIDESPREAD SHOWERS AND THUNDERSTORMS TO THE REGION MONDAY NIGHT AND TUESDAY. THIS WILL BE FOLLOWED BY A BREAK IN THE PRECIPITATION CHANCES WEDNESDAY AND THURSDAY AS AN H500 RIDGE POSITIONS ITSELF OVER THE NORTHERN PLAINS. AS THIS FEATURE MOVES EAST BY NEXT WEEKEND WILL SEE AT LEAST A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS RETURN FOR FRIDAY AND SATURDAY. THE PRIMARY FOCUS WILL BE MONDAY NIGHT. BY MONDAY AFTERNOON LOW PRESSURE WILL DEVELOP ACROSS MONTANA BRINGING A EASTERLY WIND FLOW ACROSS WEST AND CENTRAL NORTH DAKOTA. THIS WILL PULL ABUNDANT MOISTURE INTO THE REGION. MODEL SOUNDINGS FORECAST PWATS BETWEEN 1.5 AND 1.75 INCHES...OR ROUGHLY 2 STANDARD DEVIATIONS ABOVE NORMAL IF CORRECT. WITH ABUNDANT MOISTURE WILL MENTION HEAVY RAIN IN THE HWO ALONG WITH SLIGHT CHANCE SEVERE FROM SPC MONDAY NIGHT. THUNDERSTORMS WILL END TUESDAY FOLLOWED BY THE DRY WEATHER WEDNESDAYS AND THURSDAY. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 958 AM CDT SUN JUL 7 2013 WESTERN NORTH DAKOTA WILL BE THE PRIMARY FOCUS FOR SCATTERED THUNDERSTORMS TODAY AND TONIGHT...MAINLY IMPACTING KDIK/KISN. STORMS ARE EXPECTED TO BE TOO SCATTERED IN NATURE TO WARRANT MORE THAN A VCTS GROUP AT THIS TIME. OTHER THAN BRIEF MVFR VSBYS IN THE MORE INTENSE STORMS...EXPECT VFR CONDITIONS. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE/AVIATION...RP KINNEY SHORT TERM...CK LONG TERM...WAA
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1014 AM CDT SUN JUL 7 2013 .UPDATE... ISSUED AT 1009 AM CDT SUN JUL 7 2013 LOW CLOUDS AND FOG IN THE FAR EASTERN FCST AREA DISSIPATING AS EXPECTED. SOME PATCHY LOWER CLOUDS ROSEAU TO FOSSTON BUT AND THIS BAND IS RIGHT ALONG THE WEAK SFC BOUNDARY. STILL TAKE SOME TIME TO FULLY BREAKUP LOW CLOUDS IN THE EAST BUT SHOULD DO SO BY 17Z-18Z AT THE LASTEST AS WINDS START TO INCREASE ENOUGH. OTHERWISE GOT SOME HIGH CLOUDS SPREADING INTO DVL BASIN AND LIKELY WILL SPREAD INTO SOUTHWESTERN FCST AREA AHD OF AREA OF SHOWERS/STORMS MOVING THRU FAR SOUTH CENTRAL ND AND NORTHWESTERN SD. HRRR SEEMS REASONABLE IN SHOWING ANY SHOWERS DYING OUT BEFORE REACHING SOUTHWESTERN FCST AREA WITH ACTIVITY SHIFTING MORE INTO SOUTH DAKOTA. THUS DRY FCST THRU 00Z IS GOOD. TOOK HIGH TEMPS DOWN A LITTLE BIT...DUE TO SLOW START. && .SHORT TERM...(TODAY THROUGH MONDAY) ISSUED AT 258 AM CDT SUN JUL 7 2013 THE MAIN UPPER SHORTWAVE HAS BEEN LIFTING OFF INTO CANADA...WITH A SFC BOUNDARY TRAILING SOUTH INTO EASTERN ND. WINDS HAVE ALREADY SHIFTED TO THE WEST IN THE DEVILS LAKE BASIN AND DRIER AIR HAS STARTED TO MOVE IN. MOIST AIR AND LIGHT WINDS CONTINUE FROM THE RED RIVER VALLEY EASTWARD. THERE HAS BEEN SOME FOG FORMATION IN SOME SPOTS...BUT WITH THE BOUNDARY COMING THROUGH THINK THAT IT WILL BE SHORT LIVED. STORMS ALONG THE FRONT AS IT WENT THROUGH THE DEVILS LAKE BASIN HAVE DISSIPATED...BUT WILL HOLD ONTO 20 POPS FOR A BIT LONGER AS THE BOUNDARY MOVES THROUGH AND TAKE ANOTHER LOOK BEFORE SENDING GRIDS OUT. WEAK SFC HIGH PRESSURE WILL BUILD IN TODAY AND CONDITIONS WILL BE FAIRLY QUIET. WITH PLENTY OF SUN HIGHS AGAIN SHOULD RANGE FROM THE UPPER 70S TO MID 80S. NEAR ZONAL FLOW CONTINUES INTO TONIGHT...WITH A WEAK SHORTWAVE BRINGING SOME CONVECTION TO WESTERN ND. THINK THERE IS THE POSSIBILITY OF SOME ACTIVITY DRIFTING INTO OUR FAR WESTERN COUNTIES LATE TONIGHT SO KEPT LOW POPS GOING FOR NOW IN THAT AREA. THE WEAK SHORTWAVE TROUGH WILL CONTINUE TO MOVE EASTWARD INTO MONDAY...BUT THE MORE SIGNIFICANT SFC FEATURES WILL STAY TO THE WEST AS A TROUGH DEVELOPS IN THE LEE OF THE ROCKIES. WINDS WILL SHIFT BACK TO THE SOUTH AND HIGHS WILL AGAIN BE MAINLY IN THE 80S. CONTINUED TO KEEP LOW POPS GOING IN THE WEST FOR ANY ACTIVITY DRIFTING IN FROM CENTRAL ND. .LONG TERM...(MONDAY NIGHT THROUGH SATURDAY) ISSUED AT 258 AM CDT SUN JUL 7 2013 MONDAY NIGHT INTO TUESDAY...A MORE SIGNIFICANT SHORTWAVE TROUGH WILL BEGIN TO DIG DOWN INTO THE NORTHWESTERN PLAINS OUT OF CANADA AND THEN MOVE THROUGH THE DAKOTAS. THERE SHOULD BE A DECENT SFC TROUGH AND A COLD FRONT MOVING THROUGH DURING THE DAY ON TUESDAY. MODELS ARE IN FAIRLY DECENT AGREEMENT ON BRINGING PRECIP THROUGH MONDAY NIGHT INTO TUESDAY AS THE UPPER TROUGH AND SFC BOUNDARY COME THROUGH ALTHOUGH THERE ARE DIFFERENCES IN TIMING AND PLACEMENT. KEPT HIGH CHANCE TO LIKELY POPS GOING FOR NOW WITH ONLY A FEW TWEAKS. PRECIP WILL TAPER OFF TUESDAY NIGHT AS HIGH PRESSURE BUILDS IN. THE FRONT SHOULD KNOCK BACK TEMPS A FEW DEGREES TUESDAY INTO TUESDAY NIGHT. WEDNESDAY-SATURDAY...THE DEPARTING SHORTWAVE TROUGH WILL DIVE INTO THE NORTHERN GREAT LAKES ON WEDNESDAY AS UPPER RIDGING BEGINS TO AMPLIFY ACROSS THE ROCKIES. SURFACE HIGH PRESSURE BENEATH NORTHWEST FLOW ALOFT WILL RESULT IN DRY WEATHER WEDNESDAY AND THURSDAY...WITH SEASONABLE TEMPS AND LOWER HUMIDITY. TEMPS MAY CLIMB A FEW DEGREES FROM WEDNESDAY TO THURSDAY AS WARM ADVECTION/RETURN FLOW KICKS IN. FOR FRIDAY AND SATURDAY...OPERATIONAL MODELS KEEP THE AREA ON THE EDGE OF THE UPPER RIDGE/HOT DOME CENTERED ACROSS THE ROCKIES/HIGH PLAINS...IN THE VICINITY OF THE STRONGER WESTERLIES. UPPER LEVEL IMPULSES SKIRTING ALONG THE PERIPHERY OF THE RIDGE WILL HELP TO TRIGGER SCATTERED CONVECTION...BUT THE TIMING AND AMPLITUDE OF THESE DISTURBANCE IS NOT CLEAR THIS FAR OUT...SO WILL CONTINUE LOW-END POPS FRIDAY INTO SATURDAY. TEMPS TOWARDS NEXT WEEKEND CONTINUE TO LOOK SEASONABLE OVERALL. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 644 AM CDT SUN JUL 7 2013 PATCHY FOG HAS BROUGHT IFR OR LOWER CONDITIONS TO ALL BUT KDVL...WITH KBJI SEEING 1/4 TO 1/2SM FOR THE PAST FEW HOURS. THINK THAT THE REDUCED VIS WILL CONTINUE THROUGH THE NEXT HOUR OR SO IN THE RED RIVER VALLEY...AND A BIT LONGER AT KBJI. THERE SHOULD BE SOME GRADUAL IMPROVEMENT TO MVFR VIS AND THEN ALL SITES SHOULD BE VFR AFTER 16Z. WINDS WILL SHIFT TO THE NORTHWEST BY LATE MORNING. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ UPDATE...RIDDLE SHORT TERM...JR LONG TERM...JR/MAKOWSKI AVIATION...JR
AREA FORECAST DISCUSSION
NWS BISMARCK ND
642 AM CDT SUN JUL 7 2013 .UPDATE... ISSUED AT 621 AM CDT SUN JUL 7 2013 SHORTWAVE TROUGH MOVING THROUGH EASTERN MONTANA AT THIS TIME GENERATING SEVERAL CLUSTERS OF THUNDERSTORMS. THE CONVECTION ALSO SUPPORTED BY 75-90 KT ANTICYCLONICALLY CURVED H250 JET ACROSS SOUTHEAST MANITOBA. FOCUSED ON THIS AREA FOR THE MORNING UPDATE. SO RAISED THE CHANCE FOR THUNDERSTORMS SOUTHWEST. THIS EARLY CONVECTION NOT EXPECTED TO BE SEVERE. WAITING FOR BETTER INSTABILITY...STEEPER MID LEVEL LAPSE RATES AND BETTER CAPE THIS AFTERNOON. BUT ISOLATED HAIL/GUSTY WIND POSSIBLE THIS MORNING. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 345 AM CDT SUN JUL 7 2013 EARLY MORNING SURFACE ANALYSIS PLACED A WEAK SURFACE TROUGH ACROSS EASTERN NORTH DAKOTA. THE TROUGH WAS THE FOCUS FOR ISOLATED THUNDERSTORMS EARLIER THIS MORNING...BUT THEY HAVE SINCE DIMINISHED. THE TROUGH WILL MOVE SLOWLY EAST THIS MORNING...TAKING THE THREAT OF ADDITIONAL THUNDERSTORMS WITH IT. THE NEXT CONCERN WILL BE SHOWERS / THUNDERSTORMS IN EASTERN MONTANA WHICH HAVE BEEN MAKING STEADY PROGRESS TOWARDS WESTERN NORTH DAKOTA EARLY THIS MORNING. THE STORMS IN EASTERN MONTANA ARE IN PART BEING DRIVEN BY A SHORT WAVE WHICH IS EXPECTED TO MOVE INTO WESTERN NORTH DAKOTA THIS MORNING...AND INTO CENTRAL NORTH DAKOTA THIS AFTERNOON. VARIOUS MODEL SOLUTIONS (NAM / RAP / GFS / 4KM WRF) ALL SUGGEST THERE WILL BE A CHANCE OF PRECIPITATION AS THE WAVE MOVES ACROSS THE FORECAST AREA. WHERE THEY DIFFER TO SOME EXTENT IS IN THEIR COVERAGE OF PRECIPITATION. WILL HOLD ONTO CHANCE POPS ACROSS MOST OF THE FORECAST AREA TODAY / THIS EVENING WITH THE HIGHER POPS IN THE WEST. THE LATEST DAY 1 OUTLOOK PLACES THE SOUTHWEST PART OF THE STATE IN A SLIGHT RISK...WHICH APPEARS REASONABLE SINCE THAT AREA IS FORECAST TO HAVE THE GREATEST INSTABILITY THIS AFTERNOON / EVENING WITH MLCAPE VALUES OF UP TO 1500 J/KG. CONFIDENCE IN THUNDERSTORM COVERAGE LATE TONIGHT INTO EARLY MONDAY MORNING DECREASES TO SOME EXTENT AS THE INITIAL WAVE MOVES EAST. CONFLICTING SIGNALS ARE SHOWN IN THE MODEL SOLUTIONS WITH SOME SUGGESTING LIMITED THUNDERSTORM COVERAGE OVERNIGHT...WHILE OTHERS BRING ADDITIONAL THUNDERSTORMS INTO WESTERN NORTH DAKOTA FROM EASTERN MONTANA. WILL HOLD ONTO CHANCE POPS IN THE CENTRAL AND WEST...WITH SLIGHT CHANCES IN THE EAST WHERE CONFIDENCE IN ADDITIONAL CONVECTION IS LOWER. CLOUDS FROM SHOWERS / THUNDERSTORMS COULD INFLUENCE TEMPERATURES TODAY. WILL FOLLOW A BLEND OF GUIDANCE VALUES WITH HIGHS NEAR 80 NORTH...AND LOWER TO MID 80S SOUTH. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 345 AM CDT SUN JUL 7 2013 MODELS AGREE IN A SOUTHWEST FLOW ALOFT FROM THE NORTHWEST US TO THE NORTHERN PLAINS EARLY IN THE PERIOD. AN ACTIVE SHORTWAVE PATTERN WILL BRING SEVERAL SHORTWAVES THROUGH THE REGION BRINGING SOME WIDESPREAD SHOWERS AND THUNDERSTORMS TO THE REGION MONDAY NIGHT AND TUESDAY. THIS WILL BE FOLLOWED BY A BREAK IN THE PRECIPITATION CHANCES WEDNESDAY AND THURSDAY AS AN H500 RIDGE POSITIONS ITSELF OVER THE NORTHERN PLAINS. AS THIS FEATURE MOVES EAST BY NEXT WEEKEND WILL SEE AT LEAST A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS RETURN FOR FRIDAY AND SATURDAY. THE PRIMARY FOCUS WILL BE MONDAY NIGHT. BY MONDAY AFTERNOON LOW PRESSURE WILL DEVELOP ACROSS MONTANA BRINGING A EASTERLY WIND FLOW ACROSS WEST AND CENTRAL NORTH DAKOTA. THIS WILL PULL ABUNDANT MOISTURE INTO THE REGION. MODEL SOUNDINGS FORECAST PWATS BETWEEN 1.5 AND 1.75 INCHES...OR ROUGHLY 2 STANDARD DEVIATIONS ABOVE NORMAL IF CORRECT. WITH ABUNDANT MOISTURE WILL MENTION HEAVY RAIN IN THE HWO ALONG WITH SLIGHT CHANCE SEVERE FROM SPC MONDAY NIGHT. THUNDERSTORMS WILL END TUESDAY FOLLOWED BY THE DRY WEATHER WEDNESDAYS AND THURSDAY. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 621 AM CDT SUN JUL 7 2013 AT 6 AM CDT...A WEAK UPPER LEVEL DISTURBANCE WAS MOVING THROUGH EASTERN MONTANA AND WESTERN NORTH DAKOTA. A MOIST UNSTABLE AIR REMAINED ACROSS THE STATE. SCATTERED MORNING THUNDERSTORMS ARE POSSIBLE WEST. THIS WILL HAVE IMPACTS TO KDIK. MENTIONS VCTS AT FOR THE MORNING. OTHERWISE VFR AT ALL TAF SITES. ANOTHER ROUND OF THUNDERSTORMS ARE POSSIBLE LATER THIS AFTERNOON AND THIS EVENING. ALTHOUGH HIGHER IMPACTS EXPECTED TO THE SOUTHWEST...INCLUDING KDIK...DID NOT MENTION FOR KDIK TAF...AS UNCERTAINTY ON TIMING AND AREA TO GREAT TO MENTION AT THIS TIME. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...WAA SHORT TERM...CK LONG TERM...WAA AVIATION...WAA
AREA FORECAST DISCUSSION
NWS BISMARCK ND
344 AM CDT SUN JUL 7 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 345 AM CDT SUN JUL 7 2013 EARLY MORNING SURFACE ANALYSIS PLACED A WEAK SURFACE TROUGH ACROSS EASTERN NORTH DAKOTA. THE TROUGH WAS THE FOCUS FOR ISOLATED THUNDERSTORMS EARLIER THIS MORNING...BUT THEY HAVE SINCE DIMINISHED. THE TROUGH WILL MOVE SLOWLY EAST THIS MORNING...TAKING THE THREAT OF ADDITIONAL THUNDERSTORMS WITH IT. THE NEXT CONCERN WILL BE SHOWERS / THUNDERSTORMS IN EASTERN MONTANA WHICH HAVE BEEN MAKING STEADY PROGRESS TOWARDS WESTERN NORTH DAKOTA EARLY THIS MORNING. THE STORMS IN EASTERN MONTANA ARE IN PART BEING DRIVEN BY A SHORT WAVE WHICH IS EXPECTED TO MOVE INTO WESTERN NORTH DAKOTA THIS MORNING...AND INTO CENTRAL NORTH DAKOTA THIS AFTERNOON. VARIOUS MODEL SOLUTIONS (NAM / RAP / GFS / 4KM WRF) ALL SUGGEST THERE WILL BE A CHANCE OF PRECIPITATION AS THE WAVE MOVES ACROSS THE FORECAST AREA. WHERE THEY DIFFER TO SOME EXTENT IS IN THEIR COVERAGE OF PRECIPITATION. WILL HOLD ONTO CHANCE POPS ACROSS MOST OF THE FORECAST AREA TODAY / THIS EVENING WITH THE HIGHER POPS IN THE WEST. THE LATEST DAY 1 OUTLOOK PLACES THE SOUTHWEST PART OF THE STATE IN A SLIGHT RISK...WHICH APPEARS REASONABLE SINCE THAT AREA IS FORECAST TO HAVE THE GREATEST INSTABILITY THIS AFTERNOON / EVENING WITH MLCAPE VALUES OF UP TO 1500 J/KG. CONFIDENCE IN THUNDERSTORM COVERAGE LATE TONIGHT INTO EARLY MONDAY MORNING DECREASES TO SOME EXTENT AS THE INITIAL WAVE MOVES EAST. CONFLICTING SIGNALS ARE SHOWN IN THE MODEL SOLUTIONS WITH SOME SUGGESTING LIMITED THUNDERSTORM COVERAGE OVERNIGHT...WHILE OTHERS BRING ADDITIONAL THUNDERSTORMS INTO WESTERN NORTH DAKOTA FROM EASTERN MONTANA. WILL HOLD ONTO CHANCE POPS IN THE CENTRAL AND WEST...WITH SLIGHT CHANCES IN THE EAST WHERE CONFIDENCE IN ADDITIONAL CONVECTION IS LOWER. CLOUDS FROM SHOWERS / THUNDERSTORMS COULD INFLUENCE TEMPERATURES TODAY. WILL FOLLOW A BLEND OF GUIDANCE VALUES WITH HIGHS NEAR 80 NORTH...AND LOWER TO MID 80S SOUTH. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 345 AM CDT SUN JUL 7 2013 MODELS AGREE IN A SOUTHWEST FLOW ALOFT FROM THE NORTHWEST US TO THE NORTHERN PLAINS EARLY IN THE PERIOD. AN ACTIVE SHORTWAVE PATTERN WILL BRING SEVERAL SHORTWAVES THROUGH THE REGION BRINGING SOME WIDESPREAD SHOWERS AND THUNDERSTORMS TO THE REGION MONDAY NIGHT AND TUESDAY. THIS WILL BE FOLLOWED BY A BREAK IN THE PRECIPITATION CHANCES WEDNESDAY AND THURSDAY AS AN H500 RIDGE POSITIONS ITSELF OVER THE NORTHERN PLAINS. AS THIS FEATURE MOVES EAST BY NEXT WEEKEND WILL SEE AT LEAST A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS RETURN FOR FRIDAY AND SATURDAY. THE PRIMARY FOCUS WILL BE MONDAY NIGHT. BY MONDAY AFTERNOON LOW PRESSURE WILL DEVELOP ACROSS MONTANA BRINGING A EASTERLY WIND FLOW ACROSS WEST AND CENTRAL NORTH DAKOTA. THIS WILL PULL ABUNDANT MOISTURE INTO THE REGION. MODEL SOUNDINGS FORECAST PWATS BETWEEN 1.5 AND 1.75 INCHES...OR ROUGHLY 2 STANDARD DEVIATIONS ABOVE NORMAL IF CORRECT. WITH ABUNDANT MOISTURE WILL MENTION HEAVY RAIN IN THE HWO ALONG WITH SLIGHT CHANCE SEVERE FROM SPC MONDAY NIGHT. THUNDERSTORMS WILL END TUESDAY FOLLOWED BY THE DRY WEATHER WEDNESDAYS AND THURSDAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 345 AM CDT SUN JUL 7 2013 WILL CARRY A VFR FORECAST AT THE TERMINAL LOCATIONS...BUT THERE ARE A FEW CONCERNS. THE PRIMARY ISSUE WILL BE THE CHANCE OF THUNDERSTORMS...ESPECIALLY NEAR KDIK LATER THIS MORNING AS SHOWERS /THUNDERSTORMS ACROSS EASTERN MONTANA MOVE EAST INTO WESTERN NORTH DAKOTA. CONFIDENCE IS NOT HIGH ENOUGH FOR A TEMPO GROUP...SO WILL CARRY VCTS FOR NOW AND MONITOR THE TRENDS. THE REMAINDER OF THE TAF LOCATIONS APPEAR TO HAVE LESSER CHANCES FOR THUNDERSTORMS THAN KDIK...SO WILL NOT MENTION THEM AT THOSE TERMINALS. WINDS WILL STAY RELATIVELY LIGHT THROUGH THE FORECAST PERIOD AT SPEEDS OF LESS THAN 10 KTS. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...CK LONG TERM...WAA AVIATION...CK
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1159 PM EDT MON JUL 8 2013 .SYNOPSIS... A SERIES OF UPPER LEVEL DISTURBANCES WILL RESULT IN A CONTINUED CHANCE OF THUNDERSTORMS THROUGH MID WEEK. A COLD FRONT WILL PUSH THROUGH THE AREA WEDNESDAY NIGHT. BUILDING HIGH PRESSURE IN THE UPPER MIDWEST BEHIND THE FRONT WILL BRING DRIER CONDITIONS FOR THE REMAINDER OF THE WEEK. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... HAVE BECOME INCREASINGLY CONCERNED ABOUT HEAVY RAIN/FLASH FLOOD POTENTIAL FOR THE OVERNIGHT HOURS ACROSS THE NORTHERN HALF OF THE FORECAST AREA. MODELS ARE SHOWING A LOW LEVEL JET ACROSS NORTHERN OHIO THAT KEEPS AN AXIS OF MOISTURE TRANSPORT ACROSS THE REGION THROUGH THE NIGHT. GUIDANCE HAS BEEN DEVELOPING AN EAST-WEST LINE OF PRECIPITATION WHICH ONCE IT SETS UP MAY NOT MOVE MUCH AS IT BECOMES PARALLEL TO THE 0-3 KM SHEAR VECTOR. ALTHOUGH IT SHOULD BE NOTED THAT SOME RECENT RUNS OF THE HRRR AND RAP SUGGEST THAT THE CONVECTIVE LINE MAY BE ABLE TO SAG SOUTH. ALSO THE WARM CLOUD DEPTH IS DEEP WHICH WILL MAKE FOR VERY EFFICIENT RAINFALL PRODUCTION. SOME OF THE REGION ALREADY HAD HEAVY RAINFALL EARLY MONDAY MORNING WHICH SATURATED THE GROUND. ALL OF THIS SUGGESTS THAT THERE IS A SUBSTANTIAL THREAT OF FLASH FLOODING AND IT IS POSSIBLE THAT SOME LOCATIONS COULD SEE SIGNIFICANT IMPACTS OVERNIGHT. THUS HAVE EXPANDED THE FLASH FLOOD WATCH BACK WEST TO INCLUDE MOST OF THE MIAMI VALLEY AND PARTS OF THE WHITEWATER VALLEY. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/... MODELS ARE IN DISAGREEMENT WITH THE EVOLUTION OF THE RAIN FROM TONIGHT. CANNOT REMOVE A CHANCE FOR THUNDERSTORMS IN AN AIRMASS THAT HAS BEEN EXTREMELY SUPPORTIVE OF THEM FOR THE PAST WEEK OR MORE. HEAVY RAIN WILL BE A POSSIBILITY WITH ANY OF THESE STORMS...AND THE CHANCES WILL REALLY INCREASE LATE WEDNESDAY AND OVERNIGHT AS A DISTINCT COLD FRONT WITH UPPER LEVEL SUPPORT CROSSES THE AREA. UNTIL THIS TIME...MORE OF THE SAME IS EXPECTED AND HIGHS WILL GRADUALLY CREEP UPWARDS A DEGREE OR TWO EACH DAY. NIGHTTIME LOWS WILL ONLY BE MITIGATED TO BE COOLER FROM STORMS THAT MAY OR MAY NOT BE PRESENT AT TIMES...AT LEAST TUESDAY NIGHT. OUTSIDE OF THE STORMS...THE AIRMASS WILL RETAIN HIGH DEWPOINTS AND LIMIT NIGHTTIME DROPOFFS MUCH BELOW 70 DEGREES. && .LONG TERM /THURSDAY THROUGH MONDAY/... REGION WILL FIND ITSELF SPLIT BY A CDFNT AT THE BEGINNING OF THE PERIOD. THE FRONT WILL BE LOCATED NEAR THE OHIO RIVER AT 12Z THURSDAY. MODELS QUICKLY PUSH THE FRONT INTO THE APPALACHIANS AND REPLACE IT WITH HIGH PRESSURE. THIS SHOULD MEAN SOME LINGERING CONVECTION FOR THE MORNING HOURS OF THURSDAY IN THE EXTREME SOUTH...WITH DRY CONDITIONS FOR THE N. MODELS DROP AN H5 S/W INTO LAKE ERIE THURSDAY AFTN...BUT RIGHT NOW IT APPEARS THAT THE S/W WILL PRODUCE JUST SOME AFTN CLOUDS AND NOT ANY AFTN SHOWERS. HIGH PRESSURE WILL BUILD IN THURSDAY NIGHT AND WILL HOLD CONTROL INTO SATURDAY NIGHT. THIS SHOULD ALLOW THE REGION TO BEGIN TO DRY OUT. RETURN FLOW BY SUNDAY WILL BRING THE RETURN OF SCT CONVECTION FOR SUNDAY AND MONDAY. WENT WITH LOW CHC POPS FOR NOW. HIGHS THURSDAY INTO SATURDAY WILL BE A FEW DEGREES EITHER SIDE OF 80 FOR THE REGION. BY SUNDAY AND MONDAY...HIGHS WILL RISE INTO THE LOWER 80S. LOWS WILL BE IN THE LOWER 60S FOR THE FIRST HALF OF THE PERIOD...THEN THE MID 60S FOR THE LATER HALF. && .AVIATION /04Z TUESDAY THROUGH SATURDAY/... SHOWERS AND POSSIBLY SOME EMBEDDED THUNDERSTORMS WILL IMPACT THE NORTHERN TERMINALS OVERNIGHT. AT THIS POINT HAVE KEPT THE TAFS FAIRLY GENERIC WITH MVFR CONDITIONS AT WORST. BUT SOME OF THE SHOWERS COULD PRODUCE HEAVY DOWNPOURS AND TEMPORARY IFR VISIBILITIES. WILL MONITOR AND AMEND IF IT BECOMES APPARENT THAT HEAVIER RAINFALL/LOWER CONDITIONS MAY IMPACT ANY OF THE TERMINALS. AT THIS POINT IT SEEMS THAT MOST IF NOT ALL OF THE PRECIPITATION WILL STAY NORTH OF THE CINCINNATI AIRPORTS THROUGH THE NIGHT. THE CHANCE OF ADDITIONAL SHOWERS OR THUNDERSTORMS DURING THE DAY WILL DEPEND AT LEAST IN PART ON HOW PRECIPITATION EVOLVES OVERNIGHT. WITH PLENTY OF UNCERTAINTY HAVE JUST INCLUDED SOME VCSH ALONG WITH VFR CONDITIONS. OUTLOOK...GOOD CHANCE OF THUNDERSTORMS WEDNESDAY AND WEDNESDAY NIGHT. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...FLASH FLOOD WATCH UNTIL 10 AM EDT TUESDAY FOR OHZ026-034-035- 042>046-051>056-060>065-073-074. KY...NONE. IN...FLASH FLOOD WATCH UNTIL 10 AM EDT TUESDAY FOR INZ050-058-059. && $$ SYNOPSIS...FRANKS NEAR TERM... SHORT TERM...FRANKS LONG TERM...SITES AVIATION...
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
912 PM EDT MON JUL 8 2013 .SYNOPSIS... A SERIES OF UPPER LEVEL DISTURBANCES WILL RESULT IN A CONTINUED CHANCE OF THUNDERSTORMS THROUGH MID WEEK. A COLD FRONT WILL PUSH THROUGH THE AREA WEDNESDAY NIGHT. BUILDING HIGH PRESSURE IN THE UPPER MIDWEST BEHIND THE FRONT WILL BRING DRIER CONDITIONS FOR THE REMAINDER OF THE WEEK. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... HAVE BECOME INCREASINGLY CONCERNED ABOUT HEAVY RAIN/FLASH FLOOD POTENTIAL FOR THE OVERNIGHT HOURS ACROSS THE NORTHERN HALF OF THE FORECAST AREA. MODELS ARE SHOWING A LOW LEVEL JET ACROSS NORTHERN OHIO THAT KEEPS AN AXIS OF MOISTURE TRANSPORT ACROSS THE REGION THROUGH THE NIGHT. GUIDANCE HAS BEEN DEVELOPING AN EAST-WEST LINE OF PRECIPITATION WHICH ONCE IT SETS UP MAY NOT MOVE MUCH AS IT BECOMES PARALLEL TO THE 0-3 KM SHEAR VECTOR. ALTHOUGH IT SHOULD BE NOTED THAT SOME RECENT RUNS OF THE HRRR AND RAP SUGGEST THAT THE CONVECTIVE LINE MAY BE ABLE TO SAG SOUTH. ALSO THE WARM CLOUD DEPTH IS DEEP WHICH WILL MAKE FOR VERY EFFICIENT RAINFALL PRODUCTION. SOME OF THE REGION ALREADY HAD HEAVY RAINFALL EARLY MONDAY MORNING WHICH SATURATED THE GROUND. ALL OF THIS SUGGESTS THAT THERE IS A SUBSTANTIAL THREAT OF FLASH FLOODING AND IT IS POSSIBLE THAT SOME LOCATIONS COULD SEE SIGNIFICANT IMPACTS OVERNIGHT. THUS HAVE EXPANDED THE FLASH FLOOD WATCH BACK WEST TO INCLUDE MOST OF THE MIAMI VALLEY AND PARTS OF THE WHITEWATER VALLEY. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/... MODELS ARE IN DISAGREEMENT WITH THE EVOLUTION OF THE RAIN FROM TONIGHT. CANNOT REMOVE A CHANCE FOR THUNDERSTORMS IN AN AIRMASS THAT HAS BEEN EXTREMELY SUPPORTIVE OF THEM FOR THE PAST WEEK OR MORE. HEAVY RAIN WILL BE A POSSIBILITY WITH ANY OF THESE STORMS...AND THE CHANCES WILL REALLY INCREASE LATE WEDNESDAY AND OVERNIGHT AS A DISTINCT COLD FRONT WITH UPPER LEVEL SUPPORT CROSSES THE AREA. UNTIL THIS TIME...MORE OF THE SAME IS EXPECTED AND HIGHS WILL GRADUALLY CREEP UPWARDS A DEGREE OR TWO EACH DAY. NIGHTTIME LOWS WILL ONLY BE MITIGATED TO BE COOLER FROM STORMS THAT MAY OR MAY NOT BE PRESENT AT TIMES...AT LEAST TUESDAY NIGHT. OUTSIDE OF THE STORMS...THE AIRMASS WILL RETAIN HIGH DEWPOINTS AND LIMIT NIGHTTIME DROPOFFS MUCH BELOW 70 DEGREES. && .LONG TERM /THURSDAY THROUGH MONDAY/... REGION WILL FIND ITSELF SPLIT BY A CDFNT AT THE BEGINNING OF THE PERIOD. THE FRONT WILL BE LOCATED NEAR THE OHIO RIVER AT 12Z THURSDAY. MODELS QUICKLY PUSH THE FRONT INTO THE APPALACHIANS AND REPLACE IT WITH HIGH PRESSURE. THIS SHOULD MEAN SOME LINGERING CONVECTION FOR THE MORNING HOURS OF THURSDAY IN THE EXTREME SOUTH...WITH DRY CONDITIONS FOR THE N. MODELS DROP AN H5 S/W INTO LAKE ERIE THURSDAY AFTN...BUT RIGHT NOW IT APPEARS THAT THE S/W WILL PRODUCE JUST SOME AFTN CLOUDS AND NOT ANY AFTN SHOWERS. HIGH PRESSURE WILL BUILD IN THURSDAY NIGHT AND WILL HOLD CONTROL INTO SATURDAY NIGHT. THIS SHOULD ALLOW THE REGION TO BEGIN TO DRY OUT. RETURN FLOW BY SUNDAY WILL BRING THE RETURN OF SCT CONVECTION FOR SUNDAY AND MONDAY. WENT WITH LOW CHC POPS FOR NOW. HIGHS THURSDAY INTO SATURDAY WILL BE A FEW DEGREES EITHER SIDE OF 80 FOR THE REGION. BY SUNDAY AND MONDAY...HIGHS WILL RISE INTO THE LOWER 80S. LOWS WILL BE IN THE LOWER 60S FOR THE FIRST HALF OF THE PERIOD...THEN THE MID 60S FOR THE LATER HALF. && .AVIATION /01Z TUESDAY THROUGH SATURDAY/... SHOWERS AND POSSIBLY SOME EMBEDDED THUNDERSTORMS WILL IMPACT THE NORTHERN TERMINALS OVERNIGHT. AT THIS POINT HAVE KEPT THE TAFS FAIRLY GENERIC WITH MVFR CONDITIONS AT WORST. BUT SOME OF THE SHOWERS COULD PRODUCE HEAVY DOWNPOURS AND TEMPORARY IFR VISIBILITIES. WILL MONITOR AND AMEND IF IT BECOMES APPARENT THAT HEAVIER RAINFALL/LOWER CONDITIONS MAY IMPACT ANY OF THE TERMINALS. AT THIS POINT IT SEEMS THAT MOST IF NOT ALL OF THE PRECIPITATION WILL STAY NORTH OF THE CINCINNATI AIRPORTS THROUGH THE NIGHT. THE CHANCE OF ADDITIONAL SHOWERS OR THUNDERSTORMS DURING THE DAY WILL DEPEND AT LEAST IN PART ON HOW PRECIPITATION EVOLVES OVERNIGHT. WITH PLENTY OF UNCERTAINTY HAVE JUST INCLUDED SOME VCSH ALONG WITH VFR CONDITIONS. OUTLOOK...GOOD CHANCE OF THUNDERSTORMS WEDNESDAY AND WEDNESDAY NIGHT. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...FLASH FLOOD WATCH THROUGH TUESDAY MORNING FOR OHZ026-034-035- 042>046-051>056-060>062. KY...NONE. IN...FLASH FLOOD WATCH THROUGH TUESDAY MORNING FOR INZ050-058-059. && $$ SYNOPSIS...FRANKS NEAR TERM... SHORT TERM...FRANKS LONG TERM...SITES AVIATION...
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
559 PM EDT SUN JUL 7 2013 .SYNOPSIS... UPPER LEVEL LOW MOVES EAST TONIGHT. NORTHWEST FLOW THROUGH WEDNESDAY BRINGS MORE CONVECTION. A COLD FRONT PUSHES SOUTHEAST WEDNESDAY NIGHT AND THURSDAY. && .NEAR TERM /UNTIL MIDNIGHT TONIGHT/... CLOUDS HAVE PREVENTED MUCH ENERGY FROM BUILDING UP IN AREAS THAT STILL HAVE DEEPER MOISTURE. THEREFORE...SHOWERS ARE ONLY PRODUCING UP TO HALF AN INCH OF RAINFALL. WILL CANCEL FLASH FLOOD WATCH. && .SHORT TERM /MIDNIGHT TONIGHT THROUGH WEDNESDAY/... MODELS CONTINUE TO ADVERTISE THAT WEST/NORTHWEST UPPER FLOW WILL DEVELOP WITH UPPER DISTURBANCES EXPECTED TO MOVE ACROSS THE AREA. AT THE SURFACE...WEAK HIGH PRESSURE WILL GIVE WAY...ALLOWING A COLD FRONT TO APPROACH LATE. THE COMBINATION OF UPPER DISTURBANCES AND GULF MOISTURE WILL RESULT IN ON AND OFF AGAIN SHOWER AND STORM CHANCES WITH THUNDERSTORM COMPLEXES ROLLING FROM NORTHWEST TO SOUTHEAST REMAINING POSSIBLE. AS FRONT BEGINS TO APPROACH FROM THE NORTHWEST ON WEDNESDAY...SHOWER AND STORMS CHANCES SHOULD RAMP UP...AND HAVE INCLUDED LIKELY POPS ACROSS OUR SOUTHEAST OHIO COUNTIES FOR WEDNESDAY AFTERNOON. MAX TEMPERATURES WILL BE NEAR NORMAL...BUT IT WILL BE RATHER HUMID. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... GENERALLY FOLLOWED WPC THINKING FOR THIS PORTION OF THE FORECAST... WITH SOME TWEAKS. COLD FRONT IS EXPECTED TO PUSH SOUTHEAST WEDNESDAY NIGHT AND THURSDAY...WITH WEAK HIGH PRESSURE SLIDING BY TO OUR NORTH FRIDAY THROUGH SUNDAY. GFS/ECMWF BOTH ADVERTISE AN UPPER LOW WILL DEVELOP FRIDAY NIGHT...WITH A TROF EXTENDING SOUTHWEST ACROSS THE REGION. A SECOND UPPER LOW IS EXPECTED TO DEVELOP TO OUR SOUTH ON SATURDAY AND THEN RETROGRADE WITH TIME. COMBINATION OF COLD FRONT AND THE UPPER LOWS SUGGEST ANOTHER EXTENDED PERIOD OF WET WEATHER FOR MUCH OF THIS PERIOD. && .AVIATION /22Z SUNDAY THROUGH FRIDAY/... RADAR IMAGES SHOW THE BULK OF PCPN OVER THE HIGHER MOUNTAINS BY 18Z. A NEW LINE OF WEAK CONVECTION IS EVIDENT IN RADAR...DEVELOPING OVER SOUTHEAST OH. THESE SHOWERS WILL CONTINUE TO INCREASE INTO STORMS TO PRODUCE LIGHTNING. THE HRRR...NAM AND RAP DEVELOP THIS LINE OVER THE OH RIVER BY 21Z...SPREADING NORTHEAST AS IT WEAKENS BY SUNSET. THIS SECOND LINE OF CONVECTION COULD PRODUCE IFR VISIBILITIES AND THUNDER MAINLY AT HTS...PKB...AND CRW THROUGH 22Z THIS AFTERNOON. WITH NO LIGHTNING OCCURRING WITH BACK EDGE OF PCPN...AND THERMODYNAMIC AND DYNAMIC PARAMETERS INDICATED BY RAP AND NAM...KEPT THUNDER OR VCTS OVER EASTERN SITES ALONG THE OH RIVER. WATER VAPOR SATELLITE IMAGES SHOW BACK EDGE OF HIGH CLOUDS MARKING THE UPPER LEVEL JET ACROSS OH...EXTENDING SOUTH INTO NORTHEAST KY. A CONCENTRATED DRY SLOT AROUND THE UPPER LOW SUGGESTS STRATOSPHERIC INTRUSION AROUND THE LOW AT THE BASE...SPREADING INTO ITS SOUTHEAST QUADRANT. THESE FEATURES SUGGEST FRONTOGENESIS POSSIBLE AT THE MID LEVELS...THAT COULD ENHANCE THE LATER CONVECTION TO FLARE UP INTO GUSTY THUNDERSTORMS THROUGH SUNSET. ABUNDANT LOW LEVEL MOISTURE WILL KEEP POST RAINFALL LOW STRATUS OVER THE WESTERN SLOPES AND EASTERN MOUNTAINS TONIGHT...WITH CONDITIONS DETERIORATING OVERNIGHT. EXPECT IFR/LIFR STRATUS AT BKW AND EKN AFTER 06Z THROUGH 13Z MONDAY MORNING. CONDITIONS EXPECTED TO IMPROVE WIDESPREAD TO VFR BY 15Z MONDAY. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z TUESDAY... FORECAST CONFIDENCE...MEDIUM. ALTERNATE SCENARIOS: TIMING OF SHOWERS AND STORMS COULD VARY BY A COUPLE HOURS. IFR/LIFR FOG OR LOW STRATUS TIMING MAY VARY OVERNIGHT IF SKIES CLEAR FASTER THAN ANTICIPATED. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. UTC 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05 EDT 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01 CRW CONSISTENCY H H H H H H H H H M M H HTS CONSISTENCY M H H H H H H H H M H H BKW CONSISTENCY H H H H H H H H H H H H EKN CONSISTENCY H H H H H H H H M M L L PKB CONSISTENCY M H H H H H H H H M M M CKB CONSISTENCY H H H H H H H H H M M M AFTER 00Z TUESDAY... IFR FOG POSSIBLE LATE SUNDAY NIGHT. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...JSH/ARJ NEAR TERM...RPY SHORT TERM...JSH LONG TERM...JSH AVIATION...ARJ
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
237 PM EDT SUN JUL 7 2013 .SYNOPSIS... UPPER LEVEL LOW MOVES EAST TONIGHT. NORTHWEST FLOW THROUGH WEDNESDAY BRINGS MORE CONVECTION. A COLD FRONT PUSHES SOUTHEAST WEDNESDAY NIGHT AND THURSDAY. && .NEAR TERM /THROUGH MONDAY/... HRRR...RAP AND NAM MODELS SHOW A WEAK LINE OF CONVECTION DEVELOPING ACROSS THE OH VALLEY...SPREADING NORTHEAST AND WEAKENING BY SUNSET. FLASH FLOOD WATCH CONTINUES IN EFFECT FOR THE MOST PART...EXCEPT FOR SOUTHEAST OH...AND FEW COUNTIES IN NORTHEAST KY. UPPER LOW CROSSING THE IN AND OH BORDER EVIDENT IN WATER VAPOR IMAGES WILL CONTINUE ITS TRAJECTORY EAST INTO OH AND WV OVERNIGHT INTO MONDAY. THE LEADING EDGE OF UPPER/MID CLOUDS ASSOCIATED WITH UPPER LEVEL JET WILL SPREAD AREAS OF CLEARING FROM NORTHEAST KY...EAST ACROSS SOUTHEAST OH AND PORTIONS OF WV TONIGHT. THIS CLEARING IS SUGGESTED BY THE NAM/CMC AND AT SOME DEGREE THE GMOS. WIDESPREAD DENSE FOG POSSIBLE OVER AREAS WHERE SKY CLEARS OVERNIGHT AS ANTECEDENT PCPN WAS WIDESPREAD AND AMPLE LOW LEVEL MOISTURE WITH DEWPOINTS IN THE MID TO UPPER 60S. MODELS SHOW BOUNDARY LAYER WINDS AROUND 10 KNOTS TONIGHT INTO MONDAY. WENT CLOSER TO MAX DEWPOINTS DURING THE AFTERNOON HOURS FOR LOWS TONIGHT. BIAS CORRECTED USED FOR HIGHS ON MONDAY...GENERALLY IN THE LOWER 80S LOWLANDS...RANGING TO THE MID 70S HIGHEST ELEVATIONS. && .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/... MODELS CONTINUE TO ADVERTISE THAT WEST/NORTHWEST UPPER FLOW WILL DEVELOP WITH UPPER DISTURBANCES EXPECTED TO MOVE ACROSS THE AREA. AT THE SURFACE...WEAK HIGH PRESSURE WILL GIVE WAY...ALLOWING A COLD FRONT TO APPROACH LATE. THE COMBINATION OF UPPER DISTURBANCES AND GULF MOISTURE WILL RESULT IN ON AND OFF AGAIN SHOWER AND STORM CHANCES WITH THUNDERSTORM COMPLEXES ROLLING FROM NORTHWEST TO SOUTHEAST REMAINING POSSIBLE. AS FRONT BEGINS TO APPROACH FROM THE NORTHWEST ON WEDNESDAY...SHOWER AND STORMS CHANCES SHOULD RAMP UP...AND HAVE INCLUDED LIKELY POPS ACROSS OUR SOUTHEAST OHIO COUNTIES FOR WEDNESDAY AFTERNOON. MAX TEMPERATURES WILL BE NEAR NORMAL...BUT IT WILL BE RATHER HUMID. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... GENERALLY FOLLOWED WPC THINKING FOR THIS PORTION OF THE FORECAST... WITH SOME TWEAKS. COLD FRONT IS EXPECTED TO PUSH SOUTHEAST WEDNESDAY NIGHT AND THURSDAY...WITH WEAK HIGH PRESSURE SLIDING BY TO OUR NORTH FRIDAY THROUGH SUNDAY. GFS/ECMWF BOTH ADVERTISE AN UPPER LOW WILL DEVELOP FRIDAY NIGHT...WITH A TROF EXTENDING SOUTHWEST ACROSS THE REGION. A SECOND UPPER LOW IS EXPECTED TO DEVELOP TO OUR SOUTH ON SATURDAY AND THEN RETROGRADE WITH TIME. COMBINATION OF COLD FRONT AND THE UPPER LOWS SUGGEST ANOTHER EXTENDED PERIOD OF WET WEATHER FOR MUCH OF THIS PERIOD. && .AVIATION /19Z SUNDAY THROUGH FRIDAY/... RADAR IMAGES SHOW THE BULK OF PCPN OVER THE HIGHER MOUNTAINS BY 18Z. A NEW LINE OF WEAK CONVECTION IS EVIDENT IN RADAR...DEVELOPING OVER SOUTHEAST OH. THESE SHOWERS WILL CONTINUE TO INCREASE INTO STORMS TO PRODUCE LIGHTNING. THE HRRR...NAM AND RAP DEVELOP THIS LINE OVER THE OH RIVER BY 21Z...SPREADING NORTHEAST AS IT WEAKENS BY SUNSET. THIS SECOND LINE OF CONVECTION COULD PRODUCE IFR VISIBILITIES AND THUNDER MAINLY AT HTS...PKB...AND CRW THROUGH 22Z THIS AFTERNOON. WITH NO LIGHTNING OCCURRING WITH BACK EDGE OF PCPN...AND THERMODYNAMIC AND DYNAMIC PARAMETERS INDICATED BY RAP AND NAM...KEPT THUNDER OR VCTS OVER EASTERN SITES ALONG THE OH RIVER. WATER VAPOR SATELLITE IMAGES SHOW BACK EDGE OF HIGH CLOUDS MARKING THE UPPER LEVEL JET ACROSS OH...EXTENDING SOUTH INTO NORTHEAST KY. A CONCENTRATED DRY SLOT AROUND THE UPPER LOW SUGGESTS STRATOSPHERIC INTRUSION AROUND THE LOW AT THE BASE...SPREADING INTO ITS SOUTHEAST QUADRANT. THESE FEATURES SUGGEST FRONTOGENESIS POSSIBLE AT THE MID LEVELS...THAT COULD ENHANCE THE LATER CONVECTION TO FLARE UP INTO GUSTY THUNDERSTORMS THROUGH SUNSET. ABUNDANT LOW LEVEL MOISTURE WILL KEEP POST RAINFALL LOW STRATUS OVER THE WESTERN SLOPES AND EASTERN MOUNTAINS TONIGHT...WITH CONDITIONS DETERIORATING OVERNIGHT. EXPECT IFR/LIFR STRATUS AT BKW AND EKN AFTER 06Z THROUGH 13Z MONDAY MORNING. CONDITIONS EXPECTED TO IMPROVE WIDESPREAD TO VFR BY 15Z MONDAY. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z MONDAY... FORECAST CONFIDENCE...MEDIUM. ALTERNATE SCENARIOS: TIMING OF SHOWERS AND STORMS COULD VARY BY A COUPLE HOURS. IFR/LIFR FOG OR LOW STRATUS TIMING MAY VARY OVERNIGHT IF SKIES CLEAR FASTER THAN ANTICIPATED. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. UTC 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05 EDT 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01 CRW CONSISTENCY H H H H H H H H H M M H HTS CONSISTENCY M H H H H H H H H M H H BKW CONSISTENCY H H H H H H H H H H H H EKN CONSISTENCY H H H H H H H H M M L L PKB CONSISTENCY M H H H H H H H H M M M CKB CONSISTENCY H H H H H H H H H M M M AFTER 18Z MONDAY... IFR FOG POSSIBLE LATE SUNDAY NIGHT. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...FLASH FLOOD WATCH UNTIL MIDNIGHT EDT TONIGHT FOR WVZ005>011- 013>020-024>040-046-047. OH...NONE. KY...FLASH FLOOD WATCH UNTIL MIDNIGHT EDT TONIGHT FOR KYZ103-105. VA...FLASH FLOOD WATCH UNTIL MIDNIGHT EDT TONIGHT FOR VAZ003-004. && $$ SYNOPSIS...JSH/ARJ NEAR TERM...ARJ SHORT TERM...JSH LONG TERM...JSH AVIATION...ARJ
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
624 PM EDT SUN JUL 7 2013 .SYNOPSIS... A BERMUDA HIGH ANCHORED OFF THE EASTERN SEABOARD WILL CONTINUE TO FEED VERY WARM AND HUMID AIR NORTHWARD INTO THE COMMONWEALTH. DAILY CHANCES OF AFTERNOON AND EVENING SHOWERS/THUNDERSTORMS WILL PERSIST INTO THE UPCOMING WEEK. && .NEAR TERM /THROUGH MONDAY/... SEVERE THREAT WINDING DOWN RAPIDLY ACROSS FAR EASTERN PORTIONS OF MY CWA. MODERATE SHOWERS CONTINUE OVER EASTERN HALF IN THE COLD POOL AND WILL TAKE A FEW MORE HOURS TO DISSIPATE AND PROPOGATE EASTWARD. ISOLATED ACTIVITY WILL STILL BE POSSIBLE FROM LATE EVENING OVERNIGHT. ANOTHER MUGGY NIGHT IS IN STORE WITH AREAS OF RIVER VALLEY FOG MORE PREVALENT THAT RECENT MORNINGS DUE TO WIDESPREAD NATURE OF THIS AFTERNOON`S CONVECTION. MINS WILL RANGE FROM THE LOWER 60S NORTHWEST TO THE LOWER 70S SOUTHEAST. && .SHORT TERM /MONDAY NIGHT THROUGH 6 PM MONDAY/... SHORT RANGE GUIDANCE AGREES IN TRACKING THE REMNANTS OF THE AMAZINGLY PERSISTENT UPPER LOW/TROF THROUGH THE REGION OVERNIGHT AND EARLY MONDAY. THIS SYSTEM HAS ACTED AS A MOISTURE PUMP INTO THE NE US FOR OVER A WEEK AND ITS DEMISE WILL MARK A TRANSITION TO MORE OF A ZONAL FLOW ALOFT TO START THE NEW WORK WEEK. THE BEST FORCING WITH THE UPPER LOW IS EXPECTED TO PASS LATER TONIGHT...DURING THE NORMAL DIURNAL LULL IN INSTABILITY. IT WILL LIKELY KEEP A BETTER CHANCE OF SHOWERS GOING DEEPER INTO THE OVERNIGHT THAN PREVIOUS NIGHTS WITH LOCALLY HEAVY RAIN LIKELY BEING THE BIGGEST THREAT. MONDAY WILL REMAIN WARM AND HUMID AND SCATTERED CONVECTION ONCE AGAIN CANNOT BE RULED OUT...BUT CHANCES SHOULD BE LESS THAN RECENT DAYS. ENSEMBLES AGREE IN SHUNTING THE AXIS OF HIGHEST PWATS EAST OF THE AREA...AND MID LEVEL HEIGHT RISES AND WARM ADVECTION SHOULD ALL COMBINE TO LIMIT OUR INSTABILITY. TEMPS FROM NEAR 80 IN THE NW...TO THE MID 80S IN THE SE WILL BE VERY CLOSE TO NORMAL. && .LONG TERM /MONDAY NIGHT THROUGH SUNDAY/... AFTER THE PASSAGE OF THE UPPER LOW...THE UPPER PATTERN WILL BECOME QUASI-ZONAL FOR A TIME EARLY TO MID WEEK...WITH PA BEING ON THE SOUTHERN EDGE OF THE WESTERLIES. THE MODELS ARE CONSISTENT WITH PERSISTENT MOIST WESTERLY FLOW WHICH WILL LEAVE THE REGION VULNERABLE TO CONVECTION AS WEAK DISTURBANCES RIPPLE EASTWARD OUT OF THE MIDWEST AND GREAT LAKES. A STRONGER TROUGH WILL DEEPEN OVER SOUTHERN CANADA AND OVER THE GREAT LAKES REGION TOWARDS THE END OF THE WEEK. THIS SHOULD RESULT IN A FAIRLY STRONG FRONTAL PASSAGE SOMETIME LATER WED OR THU AS SLIGHTLY COOLER BUT MUCH DRIER AIR SLIDES OUT OF THE GR LAKES. FROM THERE THE UPPER PATTERN ADVERTISED IN SOME LONGER RANGE GUIDANCE TAKES ON A LOOK THAT IS EERILY FAMILIAR TO WHAT WE HAVE JUST EXPERIENCED...WITH A NEW CUTOFF LOW FCST TO FORM OVER THE EASTERN US...AND A RENEWED SURGE OF DEEP SOUTHERLY FLOW EVENTUALLY EXPECTED TO DEVELOP ONCE AGAIN OVER THE EASTERN US. A POTENTIAL COMPLICATING FACTOR IS A TROPICAL SYSTEM CURRENTLY WELL OUT IN THE ATLANTIC THAT THE TROPICAL MODELS TRACK INTO THE BAHAMAS BY LATE WEEK...MAKING A TANTALIZING FEATURE FOR THE EASTERN US TROF TO PERHAPS INTERACT WITH. WHAT HAS BEEN INTERESTING SO FAR THIS JULY HAS BEEN THE RATHER HIGH LATITUDE THE BERMUDA RIDGE HAS OCCUPIED FOR SO EARLY IN THE SEASON. THE LATEST PROGS ONCE AGAIN HAVE A STRONG CLOSED UPPER HIGH AT UNUSUALLY HIGH LATITUDES BY NEXT WEEKEND. IF THE TROPICAL SYSTEM CAN MANAGE TO HOLD TOGETHER...IT WOULD SUGGEST THE EASTERN SEABOARD WOULD BE VULNERABLE IN ABOUT A WEEK`S TIME. STAY TUNED. && .AVIATION /00Z MONDAY THROUGH FRIDAY/... LINE OF THUNDERSTORMS...ACCOMPANIED BY BRIEF GUSTY WINDS AND IFR VSBYS...IS PUSHING THRU THE SUSQ VALLEY AS OF 21Z. FOR MUCH OF CENTRAL PA...EXPECT A RETURN TO VFR CONDS WITHIN A COUPLE HOURS AFTER PASSAGE OF THUNDERSTORMS. HOWEVER...RESIDUAL LOW LVL MOISTURE ASCENDING THE W MTNS COULD PRODUCE SOME LOW CIGS ACROSS THE LAUREL HIGHLANDS THIS EVENING /JST REPORTING SCT009 AT 21Z AND K2G4 REPORTING A 800FT CIG/. THE LOW CIG THREAT COULD SPREAD NORTH ALONG THE ALLEGHENY MTNS TOWARD BFD LATE TONIGHT AS BLYR COOLS. LATEST SREF AND RAP OUTPUT BOTH SUPPORT THIS THREAT OF IFR CONDS ACROSS THE W MTNS. FURTHER EAST...FOG IS CERTAINLY A POSSIBILITY...GIVEN THE WET GROUND AND PARTIAL CLEARING EXPECTED OVERNIGHT. HOWEVER...PRES GRADIENT SUGGESTS THERE WILL BE ENOUGH OF A WIND TO PRECLUDE IFR VSBYS. AN UPPER LVL LOW WILL PUSH EAST TOWARD PA MONDAY. THIS WILL BRING ANOTHER HIGH PROB OF SHRA AND TSRA. OUTLOOK... MON...AM LOW CIGS POSS W MTNS. ISOLD THUNDERSTORM IMPACTS. TUE-THU...AM LOW CIGS POSS W MTNS. SCT THUNDERSTORM IMPACTS POSS...MAINLY DURING THE PM HOURS. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LA CORTE/RXR NEAR TERM...DEVOIR/LA CORTE/RXR SHORT TERM...LA CORTE LONG TERM...LA CORTE/GARTNER AVIATION...FITZGERALD/RXR
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
536 PM EDT SUN JUL 7 2013 .SYNOPSIS... A BERMUDA HIGH ANCHORED OFF THE EASTERN SEABOARD WILL CONTINUE TO FEED VERY WARM AND HUMID AIR NORTHWARD INTO THE COMMONWEALTH. DAILY CHANCES OF AFTERNOON AND EVENING SHOWERS/THUNDERSTORMS WILL PERSIST INTO THE UPCOMING WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... MORE OF THE SAME IN STORE FOR TODAY...WARM AND HUMID WITH SHOWERS AND THUNDERSTORMS COOKING UP WITH DAYTIME HEATING. MODELS GENERATE THE MOST CAPE OVER EASTERN SECTIONS TODAY...IN RESPONSE TO WHERE THE BEST SUNSHINE IS EXPECTED TO BE. THE ENTIRE REGION WILL REMAIN IN THE TROPICAL AIRMASS ABOVE NORMAL PWATS CONTINUE TO STREAM NORTH INTO THE AREA. SPC DOESN/T OUTLOOK THE REGION TODAY...THOUGH WE ARE IN SEE TEXT. THE SHEAR ALOFT IS FAIRLY IMPRESSIVE ON THE FRONT SIDE OF THE UPPER LOW THAT IS FINALLY BEGINNING TO SHEAR OUT OF THE TN/OH VALLEYS. AS A RESULT WE CANNOT RULE OUT SOME ISOLATED STRONGER STORMS AS ACTIVITY INCREASES LATER THIS MORNING INTO THE AFTERNOON. LOW LEVEL FOCUSING IS WEAK...SO WIDESPREAD ORGANIZED ACTIVITY DOESN/T SEEM LIKELY ACROSS THE NORTH. HOWEVER...A SUBTLE WAVE DRIFTING NORTH IN THE MID-LEVEL FLOW /YESTERDAY LOCATED IN W NC/ WILL PROVIDE A BIT MORE FOCUSED LIFT ACROSS THE SOUTH...AND COMBINED WITH MODERATE FLOW AND CAPE...COULD GENERATE MORE ORGANIZED ACTIVITY WITH SOME STRONGER STORMS POSS. THIS IS ALSO NOTED IN THE HRRR...WHICH HAS BEEN PERFORMING WELL OVER THE PAST COUPLE OF DAYS. ACTIVITY LOOKS TO BEGIN PICKING UP AFTER 18Z IN THE SW...AND IF SCENARIO PLAYS OUT - TRACKING EASTWARD THROUGH THE AFTERNOON HOURS. HIGHS TODAY LOOK LIKE THEY WILL NOT BE MUCH DIFFERENT THAN SUNDAY. ANOTHER VERY SUMMERY EARLY JULY DAY. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/... SHORT RANGE GUIDANCE AGREES IN TRACKING THE REMNANTS OF THE AMAZINGLY PERSISTENT UPPER LOW/TROF THROUGH THE REGION OVERNIGHT AND EARLY MONDAY. THIS SYSTEM HAS ACTED AS A MOISTURE PUMP INTO THE NE US FOR OVER A WEEK AND ITS DEMISE WILL MARK A TRANSITION TO MORE OF A ZONAL FLOW ALOFT TO START THE NEW WORK WEEK. THE BEST FORCING WITH THE UPPER LOW IS EXPECTED TO PASS LATER TONIGHT...DURING THE NORMAL DIURNAL LULL IN INSTABILITY. IT WILL LIKELY KEEP A BETTER CHANCE OF SHOWERS GOING DEEPER INTO THE OVERNIGHT THAN PREVIOUS NIGHTS WITH LOCALLY HEAVY RAIN LIKELY BEING THE BIGGEST THREAT. MONDAY WILL REMAIN WARM AND HUMID AND SCATTERED CONVECTION ONCE AGAIN CANNOT BE RULED OUT...BUT CHANCES SHOULD BE LESS THAN RECENT DAYS. ENSEMBLES AGREE IN SHUNTING THE AXIS OF HIGHEST PWATS EAST OF THE AREA...AND MID LEVEL HEIGHT RISES AND WARM ADVECTION SHOULD ALL COMBINE TO LIMIT OUR INSTABILITY. TEMPS FROM NEAR 80 IN THE NW...TO THE MID 80S IN THE SE WILL BE VERY CLOSE TO NORMAL. && .LONG TERM /MONDAY NIGHT THROUGH SUNDAY/... AFTER THE PASSAGE OF THE UPPER LOW...THE UPPER PATTERN WILL BECOME QUASI-ZONAL FOR A TIME EARLY TO MID WEEK...WITH PA BEING ON THE SOUTHERN EDGE OF THE WESTERLIES. THE MODELS ARE CONSISTENT WITH PERSISTENT MOIST WESTERLY FLOW WHICH WILL LEAVE THE REGION VULNERABLE TO CONVECTION AS WEAK DISTURBANCES RIPPLE EASTWARD OUT OF THE MIDWEST AND GREAT LAKES. A STRONGER TROUGH WILL DEEPEN OVER SOUTHERN CANADA AND OVER THE GREAT LAKES REGION TOWARDS THE END OF THE WEEK. THIS SHOULD RESULT IN A FAIRLY STRONG FRONTAL PASSAGE SOMETIME LATER WED OR THU AS SLIGHTLY COOLER BUT MUCH DRIER AIR SLIDES OUT OF THE GR LAKES. FROM THERE THE UPPER PATTERN ADVERTISED IN SOME LONGER RANGE GUIDANCE TAKES ON A LOOK THAT IS EERILY FAMILIAR TO WHAT WE HAVE JUST EXPERIENCED...WITH A NEW CUTOFF LOW FCST TO FORM OVER THE EASTERN US...AND A RENEWED SURGE OF DEEP SOUTHERLY FLOW EVENTUALLY EXPECTED TO DEVELOP ONCE AGAIN OVER THE EASTERN US. A POTENTIAL COMPLICATING FACTOR IS A TROPICAL SYSTEM CURRENTLY WELL OUT IN THE ATLANTIC THAT THE TROPICAL MODELS TRACK INTO THE BAHAMAS BY LATE WEEK...MAKING A TANTALIZING FEATURE FOR THE EASTERN US TROF TO PERHAPS INTERACT WITH. WHAT HAS BEEN INTERESTING SO FAR THIS JULY HAS BEEN THE RATHER HIGH LATITUDE THE BERMUDA RIDGE HAS OCCUPIED FOR SO EARLY IN THE SEASON. THE LATEST PROGS ONCE AGAIN HAVE A STRONG CLOSED UPPER HIGH AT UNUSUALLY HIGH LATITUDES BY NEXT WEEKEND. IF THE TROPICAL SYSTEM CAN MANAGE TO HOLD TOGETHER...IT WOULD SUGGEST THE EASTERN SEABOARD WOULD BE VULNERABLE IN ABOUT A WEEK`S TIME. STAY TUNED. && .AVIATION /22Z SUNDAY THROUGH FRIDAY/... LINE OF THUNDERSTORMS...ACCOMPANIED BY BRIEF GUSTY WINDS AND IFR VSBYS...IS PUSHING THRU THE SUSQ VALLEY AS OF 21Z. FOR MUCH OF CENTRAL PA...EXPECT A RETURN TO VFR CONDS WITHIN A COUPLE HOURS AFTER PASSAGE OF THUNDERSTORMS. HOWEVER...RESIDUAL LOW LVL MOISTURE ASCENDING THE W MTNS COULD PRODUCE SOME LOW CIGS ACROSS THE LAUREL HIGHLANDS THIS EVENING /JST REPORTING SCT009 AT 21Z AND K2G4 REPORTING A 800FT CIG/. THE LOW CIG THREAT COULD SPREAD NORTH ALONG THE ALLEGHENY MTNS TOWARD BFD LATE TONIGHT AS BLYR COOLS. LATEST SREF AND RAP OUTPUT BOTH SUPPORT THIS THREAT OF IFR CONDS ACROSS THE W MTNS. FURTHER EAST...FOG IS CERTAINLY A POSSIBILITY...GIVEN THE WET GROUND AND PARTIAL CLEARING EXPECTED OVERNIGHT. HOWEVER...PRES GRADIENT SUGGESTS THERE WILL BE ENOUGH OF A WIND TO PRECLUDE IFR VSBYS. AN UPPER LVL LOW WILL PUSH EAST TOWARD PA MONDAY. THIS WILL BRING ANOTHER HIGH PROB OF SHRA AND TSRA. OUTLOOK... MON...AM LOW CIGS POSS W MTNS. ISOLD THUNDERSTORM IMPACTS. TUE-THU...AM LOW CIGS POSS W MTNS. SCT THUNDERSTORM IMPACTS POSS...MAINLY DURING THE PM HOURS. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LA CORTE/RXR NEAR TERM...LA CORTE/RXR SHORT TERM...LA CORTE LONG TERM...LA CORTE/GARTNER AVIATION...FITZGERALD/RXR
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1044 PM CDT MON JUL 8 2013 .UPDATE... ISSUED AT 916 PM CDT MON JUL 8 2013 DESPITE A WAVE SEEN ON WATER VAPOR IMAGERY MOVING INTO A HIGHLY UNSTABLE AIRMASS FROM INTERSTATE 90 TO NEAR THE MISSOURI RIVER FEATURING 2000 TO 3000 J/KG OF CAPE...HAVE FAILED TO SEE MUCH IN THE WAY OF STORM DEVELOPMENT TO THIS POINT. TOUGH TO PINPOINT EXACT REASONS...BUT APPARENTLY MID LEVEL PROFILES WERE EITHER A BIT WARMER OR DRYER THAN MODELED...OR POTENTIALLY A COMBINATION OF THEM BOTH. AM SEEING SOME NEW DEVELOPMENT IN CENTRAL SOUTH DAKOTA. THESE STORMS ARE NEARLY STATIONARY. THIS MAKES SENSE GIVEN THAT MEAN CLOUD LAYER WINDS ARE LESS THAN 5 KTS. SO QUESTION REMAINS...WHAT ARE OUR STORM CHANCES. IF STORMS ARE ABLE TO ORGANIZE ALONG AN OUTFLOW...AN EAST SOUTHEAST MOTION WOULD BE EXPECTED...AS CAN BE SEEN WITH THE STORM CURRENTLY IN NORTH CENTRAL NEBRASKA. WILL CONTINUE TO MONITOR STORMS IN CENTRAL SOUTH DAKOTA. NOT OUT OF THE QUESTION THAT AS OUTFLOW FROM THE WESTERN PORTION OF THE STATE INTERACTS WITH THESE STORMS...AND THE LOW LEVEL JET PICKS UP...THAT THEY ORGANIZE AND MOVE SOUTHEAST INTO AREAS WEST OF THE JAMES RIVER VALLEY. FOR THAT REASON AFTER COORDINATION WITH SURROUNDING OFFICES AND SPC...EXTENDED THE SEVERE THUNDERSTORM WATCH UNTIL 04Z. BY THAT TIME CONVECTIVE EVOLUTION SHOULD HOPEFULLY BECOME MORE CLEAR. ONE THING GOING AGAINST STORM ORGANIZATION IS THE LARGE AREA OF DRYING SEEN ON WATER VAPOR...SUGGESTIVE OF LARGE SCALE SUBSIDENCE OVERTAKING THE AREA. EAST OF THE JAMES RIVER THE THREAT APPEARS TO BE DECREASING...ALTHOUGH AS THE LOW LEVEL JET PICKS UP CAN NOT COMPLETELY RULE OUT A FEW STORMS FORMING ANYWHERE SOUTH OF INTERSTATE 90. BUT OVERALL THE SEVERE THREAT FOR THE EVENING APPEARS TO BE DECREASING. QUESTION THEN BECOMES WHAT HAPPENS TO THE SEVERE LINE OF STORMS CURRENTLY ACROSS EASTERN MONTANA AND WESTERN NORTH DAKOTA. THIS AREA OF STORMS IS CURRENTLY PUSHING EAST SOUTHEAST...AND THE HRRR NOW SUGGESTS THAT THIS LINE COULD POSSIBLY SURVIVE INTO OUR CWA. IF STORMS THIS EVENING DO NOT MATERIALIZE THE ATMOSPHERE COULD INDEED MAINTAIN ENOUGH INSTABILITY TO SUPPORT THIS LINE. SO SOMETHING TO WATCH. IF IT DOES SURVIVE..EXPECT IT TO APPROACH THE MISSOURI RIVER BY 4 AM. WIND GUSTS TO 60 MPH WOULD SEEM POSSIBLE IN THE LINE SHALL IT HOLD TOGETHER. HAVE A TOUGH TIME BELIEVING IT WOULD MAINTAIN SEVERE INTENSITY MUCH EAST OF THE JAMES RIVER IF EVEN THAT FAR...BUT TIMING WOULD PUT IT ALONG INTERSTATE 29 NEAR 6 AM. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 353 PM CDT MON JUL 8 2013 ATTENTION IN THE SHORT TERM IS ON THE CONVECTIVE DEVELOPMENT. OUTFLOW/FRONTAL HYBRID REMAINS DISTINCT ACROSS WESTERN IOWA JUST ALONG THE SOUTHERN EDGE OF THE CWA...BUT MORE DIFFUSE HEADING WEST INTO NEBRASKA. MCV PASSING SOUTH OF CWA...AND RECENTLY HAVE SEEN LONE CONVECTIVE CELL DEVELOP ALONG THIS BOUNDARY NEAR CWA BORDER... AND NOT SURPRISED WITH RAP ANALYSIS INDICATING WEAKENED /MORE LIKELY WEAKENING/ CAP. LIKELY THAT MOST AREAS AT LEAST A WEAK CAP REMAINS /ON ORDER OF A SKINNY 20-40 J/KG/ IF SOME PRECONVECTED MODELS USED FOR GUIDANCE. NO QUESTION ATMOSPHERE IS CERTAINLY LOADING UP ON POTENTIAL ENERGY THIS AFTERNOON...BUT SOMEWHAT LESS OUT IN THE FAR WEST WHERE HAVE BEEN ALONG EDGE OF NAGGING CIRRUS SHIELD FROM EARLIER DAY ACTIVITY. THE AREA ACROSS NORTHWEST IOWA WILL BE ONE AREA OF CONVECTIVE THREAT FOR THE LATE AFTERNOON AND EARLY EVENING... AND THREATS THERE WILL BALANCE BETWEEN QUARTER TO HALF DOLLAR HAIL... AND DAMAGING WIND GUSTS. ALSO MUST NOT FORGET THAT FAIRLY WEAK WINDS ALONG WITH RIGHT MOVING SUPERCELL MOTION OF 5 TO 10 KNOTS MAXIMUM THROUGH EARLY EVENING...WITH WARM CLOUD DEPTHS OVER 12 KFT...FLASH FLOODING IS A RISK. EFFECTIVELY SHEAR IS IN THAT 30-40 KNOT RANGE...AND CERTAINLY IN THE REALM WHERE SUERCELLS WOULD CERTAINLY BE POSSIBLE...OR AT LEAST HYBRID WITH LINEAR/BOWING STRUCTURE. LOWER TO MID LEVEL STORM RELATIVE INFLOW FAIRLY BALANCED...SO MAY END UP WITH A FAIRLY STABLE BOWING STRUCTURE...AND SOMETHING TOWARD A HIGHER END DAMAGING WIND EVENT IS NOT OUT OF THE QUESTION. MOST HIGH RESOLUTION GUIDANCE IS SUPPORTIVE OF THIS MODE...AND LITTLE REASON TO DOUBT IT. FOR NOW... MOST LIKELY AREA WOULD APPEAR TO BE NEAR/SOUTH OF INTERSTATE 90 FROM THE EARLY EVENING HOURS NEAR 9V9...AROUND MIDNIGHT CLOSER TO I29...AND A BIT LATER THROUGH NW IA. IN THE WAKE OF THE MCS...WILL AGAIN BE POTENTIAL FOR SOME PATCHY FOG WHERE SKIES CAN CLEAR...AND ADDED SMALL MENTION FOR AREAS GENERALLY NEAR/SOUTH OF I90 AND NEAR/WEST OF I29. AFTER THE ATMOSPHERE BEING WORKED OVER TONIGHT...VEERING LOW LEVEL JET SHOULD QUICKLY END EARLY DAY ACTION EAST...WITH TEMPS CONTINUING TO WARM ALOFT AHEAD OF FAIRLY STRONG UPPER ENERGY...WHICH WILL SWING SOUTHEAST ACROSS THE AREA ON TUESDAY AFTERNOON. AT THE SURFACE... OUTFLOW/CONVERGENCE BOUNDARY SHOULD BE LEADING THE AREA ACROSS NORTHWEST IOWA BY MIDDAY... HOWEVER...THE STRONGER BOUNDARY/MOISTURE DISCONTINUITY WILL BE TIED TO THE UPPER ENERGY. AREAS BETWEEN THE BOUNDARIES WILL CONTINUE STIFLING HUMIDITY AND HAVE MUCH OF NW IA REACHING HEAT INDEX VALUES FROM 100 TO 105 FROM MIDDAY TOMORROW THROUGH MUCH OF THE AFTERNOON. LIKELY TO REMAIN FAIRLY CAPPED UNTIL LIFT FROM APPROACHING FRONT AND COOLING TEMPS ALOFT WITH UPPER WAVE. EFFECTIVE SHEAR LOOKS TO BE A BIT STRONGER AND QUITE LINEAR...AND A SEVERE RISK OVER THE SOUTHEASTERN 2/3 OF THE AREA LOOKS WARRANTED GIVEN THE DEGREE OF POTENTIAL INSTABILITY AND EFFECTIVE SHEAR. THREAT WOULD AGAIN BE PRIMARILY HAIL AND DAMAGING WIND. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 353 PM CDT MON JUL 8 2013 THE SHORTWAVE AND FRONTAL BOUNDARY WILL TRACK OFF TO THE EAST BY TUESDAY EVENING...WITH ANY LINGERING THUNDERSTORM ACTIVITY FOLLOWING SUIT. WITH DECENT COLD AIR ADVECTION AND DRYING BEHIND THE EXITING SYSTEM...IT WILL BE A COOLER NIGHT WITH LOWERING DEW POINTS. LOWS WILL BOTTOM OUT IN THE UPPER 50S TO LOWER 60S BY EARLY WEDNESDAY MORNING. A SURFACE RIDGE SLIDES SOUTHWARD THROUGH THE REGION ON WEDNESDAY...PROVIDING FOR A PLEASANT DAY WITH LIGHT WINDS AND DEW POINTS DOWN INTO THE 50S. HIGHS WILL BE SEASONABLE FOR THIS TIME OF YEAR WITH READINGS IN THE UPPER 70S TO LOWER 80S. THURSDAY ALSO LOOKS TO BE A DECENT DAY...ALBEIT WARMER AS HIGH PRESSURE BEGINS TO MOVE OFF TO THE EAST AND A SOUTHERLY FLOW RETURNS TO THE REGION. WITH 850 MB TEMPERATURES CLIMBING AROUND 3 DEGREES OVER WEDNESDAY...HIGHS WILL RISE INTO THE LOWER 80S EAST TO NEAR 90 THROUGH SOUTH CENTRAL SOUTH DAKOTA. IN THE EXTENDED...UPPER LEVEL RIDGE BUILDS INTO THE REGION THROUGH THE END OF THE WEEK...TRANSITIONING TO A MORE WEST-EAST FLOW BY THE START OF NEXT WEEK. THIS WILL BRING A CONTINUED WARM UP INTO SUNDAY...THEN SOME COOLING POSSIBLE BY MONDAY. AS LOW LEVEL MOISTURE AND INSTABILITY INCREASE THROUGH THE PERIOD...CONVECTION CHANCES WILL INCREASE FOR THE WEEKEND...WITH TYPICAL MODEL DIFFERENCES IN TIMING/PLACEMENT OF CONVECTION. HIGHS INTO THE WEEKEND LOOK TO GENERALLY BE IN THE MID 80S TO LOWER 90S...WITH LOWS UPPER 60S TO LOWER 70S. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1037 PM CDT MON JUL 8 2013 CONVECTION TRYING TO MOVE INTO OUR CFWA BUT NOT HAVING MUCH LUCK DESPITE ALL THE MESOSCALE INDICES SHOWING HOW UNSTABLE WE ACTUALLY ARE. INCREASING LOW LEVEL JET MAY BTTER THE CHANCES FOR STORMS ACROSS SOUTHERN PORTIONS OF THE AREA. OTHERWISE...OTHER AREAS WILL HAVE TO WAIT TO SEE IF NORTHWESTERN SD CONVECTIVE COMPLEX CONTINUES TO DEVELOP SOUTHWARD AS IT MOVES EAST. HR3 DATA INDICATES A PRETTY CHANCE OF THAT OCCURRING. HOWEVER...DUE TO THE UNCERTAINITY OF POPS AND TIMING...I KEPT OUT MENTION OF STORMS IN TAFS AFTER 09Z. SHOULD SEE ANOTHER ROUND OF STORMS ON TUESDAY AFTER 19Z OR SO. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ UPDATE...CHENARD SHORT TERM...CHAPMAN LONG TERM...JM AVIATION...HEITKAMP
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
916 PM CDT MON JUL 8 2013 .UPDATE... ISSUED AT 916 PM CDT MON JUL 8 2013 DESPITE A WAVE SEEN ON WATER VAPOR IMAGERY MOVING INTO A HIGHLY UNSTABLE AIRMASS FROM INTERSTATE 90 TO NEAR THE MISSOURI RIVER FEATURING 2000 TO 3000 J/KG OF CAPE...HAVE FAILED TO SEE MUCH IN THE WAY OF STORM DEVELOPMENT TO THIS POINT. TOUGH TO PINPOINT EXACT REASONS...BUT APPARENTLY MID LEVEL PROFILES WERE EITHER A BIT WARMER OR DRYER THAN MODELED...OR POTENTIALLY A COMBINATION OF THEM BOTH. AM SEEING SOME NEW DEVELOPMENT IN CENTRAL SOUTH DAKOTA. THESE STORMS ARE NEARLY STATIONARY. THIS MAKES SENSE GIVEN THAT MEAN CLOUD LAYER WINDS ARE LESS THAN 5 KTS. SO QUESTION REMAINS...WHAT ARE OUR STORM CHANCES. IF STORMS ARE ABLE TO ORGANIZE ALONG AN OUTFLOW...AN EAST SOUTHEAST MOTION WOULD BE EXPECTED...AS CAN BE SEEN WITH THE STORM CURRENTLY IN NORTH CENTRAL NEBRASKA. WILL CONTINUE TO MONITOR STORMS IN CENTRAL SOUTH DAKOTA. NOT OUT OF THE QUESTION THAT AS OUTFLOW FROM THE WESTERN PORTION OF THE STATE INTERACTS WITH THESE STORMS...AND THE LOW LEVEL JET PICKS UP...THAT THEY ORGANIZE AND MOVE SOUTHEAST INTO AREAS WEST OF THE JAMES RIVER VALLEY. FOR THAT REASON AFTER COORDINATION WITH SURROUNDING OFFICES AND SPC...EXTENDED THE SEVERE THUNDERSTORM WATCH UNTIL 04Z. BY THAT TIME CONVECTIVE EVOLUTION SHOULD HOPEFULLY BECOME MORE CLEAR. ONE THING GOING AGAINST STORM ORGANIZATION IS THE LARGE AREA OF DRYING SEEN ON WATER VAPOR...SUGGESTIVE OF LARGE SCALE SUBSIDENCE OVERTAKING THE AREA. EAST OF THE JAMES RIVER THE THREAT APPEARS TO BE DECREASING...ALTHOUGH AS THE LOW LEVEL JET PICKS UP CAN NOT COMPLETELY RULE OUT A FEW STORMS FORMING ANYWHERE SOUTH OF INTERSTATE 90. BUT OVERALL THE SEVERE THREAT FOR THE EVENING APPEARS TO BE DECREASING. QUESTION THEN BECOMES WHAT HAPPENS TO THE SEVERE LINE OF STORMS CURRENTLY ACROSS EASTERN MONTANA AND WESTERN NORTH DAKOTA. THIS AREA OF STORMS IS CURRENTLY PUSHING EAST SOUTHEAST...AND THE HRRR NOW SUGGESTS THAT THIS LINE COULD POSSIBLY SURVIVE INTO OUR CWA. IF STORMS THIS EVENING DO NOT MATERIALIZE THE ATMOSPHERE COULD INDEED MAINTAIN ENOUGH INSTABILITY TO SUPPORT THIS LINE. SO SOMETHING TO WATCH. IF IT DOES SURVIVE..EXPECT IT TO APPROACH THE MISSOURI RIVER BY 4 AM. WIND GUSTS TO 60 MPH WOULD SEEM POSSIBLE IN THE LINE SHALL IT HOLD TOGETHER. HAVE A TOUGH TIME BELIEVING IT WOULD MAINTAIN SEVERE INTENSITY MUCH EAST OF THE JAMES RIVER IF EVEN THAT FAR...BUT TIMING WOULD PUT IT ALONG INTERSTATE 29 NEAR 6 AM. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 353 PM CDT MON JUL 8 2013 ATTENTION IN THE SHORT TERM IS ON THE CONVECTIVE DEVELOPMENT. OUTFLOW/FRONTAL HYBRID REMAINS DISTINCT ACROSS WESTERN IOWA JUST ALONG THE SOUTHERN EDGE OF THE CWA...BUT MORE DIFFUSE HEADING WEST INTO NEBRASKA. MCV PASSING SOUTH OF CWA...AND RECENTLY HAVE SEEN LONE CONVECTIVE CELL DEVELOP ALONG THIS BOUNDARY NEAR CWA BORDER... AND NOT SURPRISED WITH RAP ANALYSIS INDICATING WEAKENED /MORE LIKELY WEAKENING/ CAP. LIKELY THAT MOST AREAS AT LEAST A WEAK CAP REMAINS /ON ORDER OF A SKINNY 20-40 J/KG/ IF SOME PRECONVECTED MODELS USED FOR GUIDANCE. NO QUESTION ATMOSPHERE IS CERTAINLY LOADING UP ON POTENTIAL ENERGY THIS AFTERNOON...BUT SOMEWHAT LESS OUT IN THE FAR WEST WHERE HAVE BEEN ALONG EDGE OF NAGGING CIRRUS SHIELD FROM EARLIER DAY ACTIVITY. THE AREA ACROSS NORTHWEST IOWA WILL BE ONE AREA OF CONVECTIVE THREAT FOR THE LATE AFTERNOON AND EARLY EVENING... AND THREATS THERE WILL BALANCE BETWEEN QUARTER TO HALF DOLLAR HAIL... AND DAMAGING WIND GUSTS. ALSO MUST NOT FORGET THAT FAIRLY WEAK WINDS ALONG WITH RIGHT MOVING SUPERCELL MOTION OF 5 TO 10 KNOTS MAXIMUM THROUGH EARLY EVENING...WITH WARM CLOUD DEPTHS OVER 12 KFT...FLASH FLOODING IS A RISK. EFFECTIVELY SHEAR IS IN THAT 30-40 KNOT RANGE...AND CERTAINLY IN THE REALM WHERE SUERCELLS WOULD CERTAINLY BE POSSIBLE...OR AT LEAST HYBRID WITH LINEAR/BOWING STRUCTURE. LOWER TO MID LEVEL STORM RELATIVE INFLOW FAIRLY BALANCED...SO MAY END UP WITH A FAIRLY STABLE BOWING STRUCTURE...AND SOMETHING TOWARD A HIGHER END DAMAGING WIND EVENT IS NOT OUT OF THE QUESTION. MOST HIGH RESOLUTION GUIDANCE IS SUPPORTIVE OF THIS MODE...AND LITTLE REASON TO DOUBT IT. FOR NOW... MOST LIKELY AREA WOULD APPEAR TO BE NEAR/SOUTH OF INTERSTATE 90 FROM THE EARLY EVENING HOURS NEAR 9V9...AROUND MIDNIGHT CLOSER TO I29...AND A BIT LATER THROUGH NW IA. IN THE WAKE OF THE MCS...WILL AGAIN BE POTENTIAL FOR SOME PATCHY FOG WHERE SKIES CAN CLEAR...AND ADDED SMALL MENTION FOR AREAS GENERALLY NEAR/SOUTH OF I90 AND NEAR/WEST OF I29. AFTER THE ATMOSPHERE BEING WORKED OVER TONIGHT...VEERING LOW LEVEL JET SHOULD QUICKLY END EARLY DAY ACTION EAST...WITH TEMPS CONTINUING TO WARM ALOFT AHEAD OF FAIRLY STRONG UPPER ENERGY...WHICH WILL SWING SOUTHEAST ACROSS THE AREA ON TUESDAY AFTERNOON. AT THE SURFACE... OUTFLOW/CONVERGENCE BOUNDARY SHOULD BE LEADING THE AREA ACROSS NORTHWEST IOWA BY MIDDAY... HOWEVER...THE STRONGER BOUNDARY/MOISTURE DISCONTINUITY WILL BE TIED TO THE UPPER ENERGY. AREAS BETWEEN THE BOUNDARIES WILL CONTINUE STIFLING HUMIDITY AND HAVE MUCH OF NW IA REACHING HEAT INDEX VALUES FROM 100 TO 105 FROM MIDDAY TOMORROW THROUGH MUCH OF THE AFTERNOON. LIKELY TO REMAIN FAIRLY CAPPED UNTIL LIFT FROM APPROACHING FRONT AND COOLING TEMPS ALOFT WITH UPPER WAVE. EFFECTIVE SHEAR LOOKS TO BE A BIT STRONGER AND QUITE LINEAR...AND A SEVERE RISK OVER THE SOUTHEASTERN 2/3 OF THE AREA LOOKS WARRANTED GIVEN THE DEGREE OF POTENTIAL INSTABILITY AND EFFECTIVE SHEAR. THREAT WOULD AGAIN BE PRIMARILY HAIL AND DAMAGING WIND. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 353 PM CDT MON JUL 8 2013 THE SHORTWAVE AND FRONTAL BOUNDARY WILL TRACK OFF TO THE EAST BY TUESDAY EVENING...WITH ANY LINGERING THUNDERSTORM ACTIVITY FOLLOWING SUIT. WITH DECENT COLD AIR ADVECTION AND DRYING BEHIND THE EXITING SYSTEM...IT WILL BE A COOLER NIGHT WITH LOWERING DEW POINTS. LOWS WILL BOTTOM OUT IN THE UPPER 50S TO LOWER 60S BY EARLY WEDNESDAY MORNING. A SURFACE RIDGE SLIDES SOUTHWARD THROUGH THE REGION ON WEDNESDAY...PROVIDING FOR A PLEASANT DAY WITH LIGHT WINDS AND DEW POINTS DOWN INTO THE 50S. HIGHS WILL BE SEASONABLE FOR THIS TIME OF YEAR WITH READINGS IN THE UPPER 70S TO LOWER 80S. THURSDAY ALSO LOOKS TO BE A DECENT DAY...ALBEIT WARMER AS HIGH PRESSURE BEGINS TO MOVE OFF TO THE EAST AND A SOUTHERLY FLOW RETURNS TO THE REGION. WITH 850 MB TEMPERATURES CLIMBING AROUND 3 DEGREES OVER WEDNESDAY...HIGHS WILL RISE INTO THE LOWER 80S EAST TO NEAR 90 THROUGH SOUTH CENTRAL SOUTH DAKOTA. IN THE EXTENDED...UPPER LEVEL RIDGE BUILDS INTO THE REGION THROUGH THE END OF THE WEEK...TRANSITIONING TO A MORE WEST-EAST FLOW BY THE START OF NEXT WEEK. THIS WILL BRING A CONTINUED WARM UP INTO SUNDAY...THEN SOME COOLING POSSIBLE BY MONDAY. AS LOW LEVEL MOISTURE AND INSTABILITY INCREASE THROUGH THE PERIOD...CONVECTION CHANCES WILL INCREASE FOR THE WEEKEND...WITH TYPICAL MODEL DIFFERENCES IN TIMING/PLACEMENT OF CONVECTION. HIGHS INTO THE WEEKEND LOOK TO GENERALLY BE IN THE MID 80S TO LOWER 90S...WITH LOWS UPPER 60S TO LOWER 70S. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING) ISSUED AT 625 PM CDT MON JUL 8 2013 MAIN FORECAST CONCERN IS THUNDERSTORM DEVELOPMENT IN THE SHORT TERM. AT THIS POINT...THE MOST FAVORED AREAS ARE SOUTH OF INTERSTATE 90 SO THAT INCLUDES KFSD AND KSUX. EARLIER THOUGHTS OF MCS DEVELOPMENT MAY BE DECREASING BUT WILL HAVE TO KEEP AN EYE ON SOUTHCENTRAL SD AND NORTHCENTRAL NE AS MAIN WAVE INTERACTS WITH EXISTING CONVECTION. IF MORE ORGANIZED STORMS DO NOT DEVELOP THEN MCS POSSIBILITIES ARE LOW. WITH THAT IN MIND TOOK OUT MENTION OF FOG IN KFSD AS CHANCES ARE REMOTE AT BEST. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ UPDATE...CHENARD SHORT TERM...CHAPMAN LONG TERM...JM AVIATION...HEITKAMP
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
634 PM CDT MON JUL 8 2013 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 353 PM CDT MON JUL 8 2013 ATTENTION IN THE SHORT TERM IS ON THE CONVECTIVE DEVELOPMENT. OUTFLOW/FRONTAL HYBRID REMAINS DISTINCT ACROSS WESTERN IOWA JUST ALONG THE SOUTHERN EDGE OF THE CWA...BUT MORE DIFFUSE HEADING WEST INTO NEBRASKA. MCV PASSING SOUTH OF CWA...AND RECENTLY HAVE SEEN LONE CONVECTIVE CELL DEVELOP ALONG THIS BOUNDARY NEAR CWA BORDER... AND NOT SURPRISED WITH RAP ANALYSIS INDICATING WEAKENED /MORE LIKELY WEAKENING/ CAP. LIKELY THAT MOST AREAS AT LEAST A WEAK CAP REMAINS /ON ORDER OF A SKINNY 20-40 J/KG/ IF SOME PRECONVECTED MODELS USED FOR GUIDANCE. NO QUESTION ATMOSPHERE IS CERTAINLY LOADING UP ON POTENTIAL ENERGY THIS AFTERNOON...BUT SOMEWHAT LESS OUT IN THE FAR WEST WHERE HAVE BEEN ALONG EDGE OF NAGGING CIRRUS SHIELD FROM EARLIER DAY ACTIVITY. THE AREA ACROSS NORTHWEST IOWA WILL BE ONE AREA OF CONVECTIVE THREAT FOR THE LATE AFTERNOON AND EARLY EVENING... AND THREATS THERE WILL BALANCE BETWEEN QUARTER TO HALF DOLLAR HAIL... AND DAMAGING WIND GUSTS. ALSO MUST NOT FORGET THAT FAIRLY WEAK WINDS ALONG WITH RIGHT MOVING SUPERCELL MOTION OF 5 TO 10 KNOTS MAXIMUM THROUGH EARLY EVENING...WITH WARM CLOUD DEPTHS OVER 12 KFT...FLASH FLOODING IS A RISK. EFFECTIVELY SHEAR IS IN THAT 30-40 KNOT RANGE...AND CERTAINLY IN THE REALM WHERE SUERCELLS WOULD CERTAINLY BE POSSIBLE...OR AT LEAST HYBRID WITH LINEAR/BOWING STRUCTURE. LOWER TO MID LEVEL STORM RELATIVE INFLOW FAIRLY BALANCED...SO MAY END UP WITH A FAIRLY STABLE BOWING STRUCTURE...AND SOMETHING TOWARD A HIGHER END DAMAGING WIND EVENT IS NOT OUT OF THE QUESTION. MOST HIGH RESOLUTION GUIDANCE IS SUPPORTIVE OF THIS MODE...AND LITTLE REASON TO DOUBT IT. FOR NOW... MOST LIKELY AREA WOULD APPEAR TO BE NEAR/SOUTH OF INTERSTATE 90 FROM THE EARLY EVENING HOURS NEAR 9V9...AROUND MIDNIGHT CLOSER TO I29...AND A BIT LATER THROUGH NW IA. IN THE WAKE OF THE MCS...WILL AGAIN BE POTENTIAL FOR SOME PATCHY FOG WHERE SKIES CAN CLEAR...AND ADDED SMALL MENTION FOR AREAS GENERALLY NEAR/SOUTH OF I90 AND NEAR/WEST OF I29. AFTER THE ATMOSPHERE BEING WORKED OVER TONIGHT...VEERING LOW LEVEL JET SHOULD QUICKLY END EARLY DAY ACTION EAST...WITH TEMPS CONTINUING TO WARM ALOFT AHEAD OF FAIRLY STRONG UPPER ENERGY...WHICH WILL SWING SOUTHEAST ACROSS THE AREA ON TUESDAY AFTERNOON. AT THE SURFACE... OUTFLOW/CONVERGENCE BOUNDARY SHOULD BE LEADING THE AREA ACROSS NORTHWEST IOWA BY MIDDAY... HOWEVER...THE STRONGER BOUNDARY/MOISTURE DISCONTINUITY WILL BE TIED TO THE UPPER ENERGY. AREAS BETWEEN THE BOUNDARIES WILL CONTINUE STIFLING HUMIDITY AND HAVE MUCH OF NW IA REACHING HEAT INDEX VALUES FROM 100 TO 105 FROM MIDDAY TOMORROW THROUGH MUCH OF THE AFTERNOON. LIKELY TO REMAIN FAIRLY CAPPED UNTIL LIFT FROM APPROACHING FRONT AND COOLING TEMPS ALOFT WITH UPPER WAVE. EFFECTIVE SHEAR LOOKS TO BE A BIT STRONGER AND QUITE LINEAR...AND A SEVERE RISK OVER THE SOUTHEASTERN 2/3 OF THE AREA LOOKS WARRANTED GIVEN THE DEGREE OF POTENTIAL INSTABILITY AND EFFECTIVE SHEAR. THREAT WOULD AGAIN BE PRIMARILY HAIL AND DAMAGING WIND. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 353 PM CDT MON JUL 8 2013 THE SHORTWAVE AND FRONTAL BOUNDARY WILL TRACK OFF TO THE EAST BY TUESDAY EVENING...WITH ANY LINGERING THUNDERSTORM ACTIVITY FOLLOWING SUIT. WITH DECENT COLD AIR ADVECTION AND DRYING BEHIND THE EXITING SYSTEM...IT WILL BE A COOLER NIGHT WITH LOWERING DEW POINTS. LOWS WILL BOTTOM OUT IN THE UPPER 50S TO LOWER 60S BY EARLY WEDNESDAY MORNING. A SURFACE RIDGE SLIDES SOUTHWARD THROUGH THE REGION ON WEDNESDAY...PROVIDING FOR A PLEASANT DAY WITH LIGHT WINDS AND DEW POINTS DOWN INTO THE 50S. HIGHS WILL BE SEASONABLE FOR THIS TIME OF YEAR WITH READINGS IN THE UPPER 70S TO LOWER 80S. THURSDAY ALSO LOOKS TO BE A DECENT DAY...ALBEIT WARMER AS HIGH PRESSURE BEGINS TO MOVE OFF TO THE EAST AND A SOUTHERLY FLOW RETURNS TO THE REGION. WITH 850 MB TEMPERATURES CLIMBING AROUND 3 DEGREES OVER WEDNESDAY...HIGHS WILL RISE INTO THE LOWER 80S EAST TO NEAR 90 THROUGH SOUTH CENTRAL SOUTH DAKOTA. IN THE EXTENDED...UPPER LEVEL RIDGE BUILDS INTO THE REGION THROUGH THE END OF THE WEEK...TRANSITIONING TO A MORE WEST-EAST FLOW BY THE START OF NEXT WEEK. THIS WILL BRING A CONTINUED WARM UP INTO SUNDAY...THEN SOME COOLING POSSIBLE BY MONDAY. AS LOW LEVEL MOISTURE AND INSTABILITY INCREASE THROUGH THE PERIOD...CONVECTION CHANCES WILL INCREASE FOR THE WEEKEND...WITH TYPICAL MODEL DIFFERENCES IN TIMING/PLACEMENT OF CONVECTION. HIGHS INTO THE WEEKEND LOOK TO GENERALLY BE IN THE MID 80S TO LOWER 90S...WITH LOWS UPPER 60S TO LOWER 70S. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING) ISSUED AT 625 PM CDT MON JUL 8 2013 MAIN FORECAST CONCERN IS THUNDERSTORM DEVELOPMENT IN THE SHORT TERM. AT THIS POINT...THE MOST FAVORED AREAS ARE SOUTH OF INTERSTATE 90 SO THAT INCLUDES KFSD AND KSUX. EARLIER THOUGHTS OF MCS DEVELOPMENT MAY BE DECREASING BUT WILL HAVE TO KEEP AN EYE ON SOUTHCENTRAL SD AND NORTHCENTRAL NE AS MAIN WAVE INTERACTS WITH EXISTING CONVECTION. IF MORE ORGANIZED STORMS DO NOT DEVELOP THEN MCS POSSIBILITIES ARE LOW. WITH THAT IN MIND TOOK OUT MENTION OF FOG IN KFSD AS CHANCES ARE REMOTE AT BEST. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ SHORT TERM...CHAPMAN LONG TERM...JM AVIATION...HEITKAMP
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1237 PM CDT SUN JUL 7 2013 .UPDATE... ISSUED AT 1054 AM CDT SUN JUL 7 2013 INTERESTING FORECAST FOR TODAY. WEAK UPPER WAVE GENERATING AN AREA OF ELEVATED SHOWERS AND STORMS ACROSS CENTRAL SOUTH DAKOTA THIS MORNING. AS THIS WAVE MOVES EAST OUR CWA WILL SEE WEAK UPPER FORCING FOR ASCENT. EXPECT CIRRUS FROM THIS ACTIVITY TO WORK ITS WAY INTO OUR WESTERN CWA AS WE HEAD INTO THIS AFTERNOON. MEANWHILE FRONTAL BOUNDARY IS TAKING ITS SLOW TIME MOVING SOUTH ACROSS OUR CWA. SO QUESTION BECOMES WHAT ARE OUR CONVECTION CHANCES THIS AFTERNOON. A COUPLE THINGS TO WATCH WILL BE DEWPOINT EVOLUTION AND CONVECTIVE EVOLUTION ACROSS CENTRAL AND WESTERN SOUTH DAKOTA. MOISTURE POOLING BEHIND THE FRONT IS CURRENTLY ALLOWING DEWPOINTS TO CREEP INTO THE LOW 70S IN SPOTS. A LOT OF GUIDANCE SUGGEST THESE DEWPOINTS MAY STRUGGLE TO MIX OUT...WITH RELATIVELY DEEP MOISTURE PRESENT UP TO ABOUT 850 MB...AND WEAK FLOW. AS TEMPERATURES RISE INTO THE 80S THIS AFTERNOON...MLCAPE COULD END UP IN THE 2000 TO 3000 J/KG RANGE IN THE AREA OF MOISTURE POOLING. CIN WOULD ALSO BECOME ALMOST ZERO. HOWEVER A VERY DRY LAYER AROUND 700 MB WILL LIKELY HINDER UPDRAFTS SOMEWHAT...AND DESPITE THE BOUNDARY NEARBY...SEE VERY LITTLE IN THE WAY OF LOW LEVEL CONVERGENCE OR FORCING FOR ASCENT. SO IT WOULD COME DOWN TO WHETHER THE INSTABILITY AND WEAK UPPER FORCING WOULD BE ENOUGH TO GET DEEP CU THROUGH THE DRY AIR. HI RES GUIDANCE...SUCH AS THE 06Z WRF ARW AND 12Z 4KM NAM BOTH SUGGEST THIS MAY HAPPEN. THUS WENT AHEAD AND ADDED IN A SLIGHT CHANCE OF STORMS THIS AFTERNOON AND EVENING ACROSS PORTIONS OF OUR CWA. AGAIN THIS IS REALLY DEPENDENT ON IF WE CAN KEEP DEWPOINTS IN THE LOWER 70S. IF THEY FAIL TO MATERIALIZE...THEN DRY AIR ALOFT AND WARM LAYER BETWEEN 800 AND 600 MB WILL LIKELY BE ENOUGH TO CAP CONVECTION. WIND SHEAR IS WEAK...THUS ANY STORM WOULD BE PULSE OR POSSIBLY MULTICELL TYPE. BUT GIVEN WHAT WOULD BE HIGH INSTABILITY...WOULD EXPECT AT LEAST THE THREAT OF QUARTER SIZE HAIL AND 60 MPH WIND GUSTS IN ANY STORM. HRRR DEVELOPS CONVECTION IN CENTRAL SOUTH DAKOTA THIS AFTERNOON...AND MOVES IT INTO OUR WESTERN CWA LATER THIS AFTERNOON AND EVENING. GIVEN EXTENSIVE CLOUD COVER IN THIS AREA...FEEL SURFACE BASED INITIATION IN CENTRAL SOUTH DAKOTA IS UNLIKELY THIS AFTERNOON...THUS BELIEVE THE HRRR SOLUTION IS PROBABLY NOT ACCURATE...AND SO WILL HOLD OFF ON ADDING IN ANY POPS IN OUR WEST THROUGH 0Z. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 430 AM CDT SUN JUL 7 2013 TODAY AND MUCH OF TONIGHT SHOULD REMAIN QUIET IN OUR AREA DESPITE MESSY...WAVE-RIDDLED MID LEVEL FLOW PATTERN BETWEEN DOMINANT RIDGE BUILDING WESTWARD ACROSS THE SOUTHERN CONUS AND VARIOUS TROUGHS TRACKING EASTWARD THROUGH THE CANADIAN PRAIRIES. IN THE NEAR TERM... SEEING SOME ACCAS AND SPOTTY SHOWERS DEVELOP IN WESTERN IOWA AHEAD OF WEAK WAVE. SHOWERS ARE NOT EXPECTED TO IMPACT OUR FORECAST AREA THIS MORNING THOUGH COULD SEE A LITTLE OF THE ACCAS IN OUR FAR EAST EARLY BEFORE WEAK WAVE PASSES BY. WEAK SURFACE BOUNDARY STILL WEST OF I-29 AS OF 08Z MOVING SOUTHEAST MORE SLOWLY THAN EXPECTED AT THIS TIME YESTERDAY...THOUGH STILL EXPECTED TO MAKE SOME EASTWARD PROGRESS THROUGH THE DAY...REACHING NEAR/JUST EAST OF HIGHWAY 60 CORRIDOR IN NORTHWEST IOWA BY LATE AFTERNOON. WITH WEAK LOW LEVEL FLOW...EXPECT HIGHER MOISTURE LEVELS TO POOL NEAR THE BOUNDARY...WITH DEW POINTS IN NORTHWEST IOWA NEAR 70 WHILE TEMPERATURES CLIMB INTO THE LOWER 90S THIS AFTERNOON. THIS SHOULD LEAD TO FAIR AMOUNT OF INSTABILITY WHICH COULD POP A STRAY STORM OR TWO WITH WEAK CONVERGENCE ALONG THE BOUNDARY TOWARD EVENING. WILL HANG ONTO SLIGHT CHANCE FOR NOW...BUT IF SOME HIGH RES MODELS SUCH AS RAP/HRRR TURN OUT TO BE ACCURATE IN THEIR DEPICTION OF DEW POINTS MIXING MUCH LOWER THAN EXPECTED ACROSS OUR SOUTHEAST THIS AFTERNOON...THEN CAP WOULD BE STRONGER AND WOULD NOT SEE ANY DEVELOPMENT. WILL BE SOMETHING TO WATCH THROUGH THE DAY. LATER TONIGHT...WILL BE LOOKING WESTWARD FOR POTENTIAL OF HIGH PLAINS CONVECTION TO WORK TOWARD OUR WESTERN COUNTIES. STILL FAIR AMOUNT OF INSTABILITY FOR STORMS TO WORK WITH AS THEY PUSH TOWARD THE MISSOURI VALLEY AFTER MIDNIGHT. WILL CONTINUE TO CARRY CHANCE INTO AREAS ALONG AND WEST OF THE JAMES VALLEY. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 430 AM CDT SUN JUL 7 2013 IF STORMS DO WORK INTO THE WEST LATE TONIGHT...SHOULD SEE THEM LINGER INTO THE MORNING HOURS ACROSS OUR WEST AND WILL HANG ONTO CHANCE WEST OF I-29 FOR NOW. HOWEVER THIS PERIOD COULD JUST AS LIKELY BE DRY...AS SOME MODELS INDICATING HIGH PLAINS CONVECTION WILL NOT SURVIVE THIS FAR EAST. ALL-IN-ALL...LOW CONFIDENCE IN PRECIP CHANCES ACROSS OUR WEST LATE TONIGHT/MONDAY MORNING. CONFIDENCE SOMEWHAT HIGHER THAT WE WILL SEE DEVELOPMENT ACROSS OUR SOUTH BY MID-LATE AFTERNOON MONDAY... AS WARM FRONT LIFTS BACK TO NEAR THE MISSOURI RIVER VALLEY AND MID LEVEL HEIGHTS COLLAPSE IN ADVANCE OF APPROACHING WAVE. WITH LITTLE FLOW NEAR THE BOUNDARY...SHOULD CONTINUE TO SEE LOW LEVEL MOISTURE BUILD AND ENHANCE INSTABILITY. ALSO START TO SEE BETTER DEEP LAYER SHEAR WORK INTO THE REGION...LOCALLY ENHANCED ALONG THE BOUNDARY. FOR THIS REASON...MONDAY AFTERNOON/EVENING LOOKS TO HAVE FAIR POTENTIAL FOR SEVERE STORMS AS WAVE /IN SOME MODELS/ SLIDES NORTHEAST ACROSS THE FRONTAL BOUNDARY. EVOLUTION OF PRECIP BEYOND THIS SOMEWHAT MUDDLED BY POTENTIAL FOR LINGERING OUTFLOW BOUNDARIES...BUT GENERALLY EXPECT MOST MONDAY NIGHT ACTIVITY TO WORK EAST OF THE FORECAST AREA BY EARLY TUESDAY. COLD FRONT WILL BE PUSHING SOUTHEAST THROUGH THE FORECAST AREA TUESDAY AFTERNOON...AND EXPECT STRONG WARMING INTO THE LOWER TO MID 90S IN THERMAL RIDGE AHEAD OF THE FRONT. HUMIDITY LINGERS AS WELL...WITH DEW POINTS IN THE LOWER OR EVEN MID 70S POSSIBLE ACROSS MUCH OF THE AREA. THIS WILL GIVE FRONT PLENTY OF INSTABILITY TO FEED ON...WITH STORM DEVELOPMENT AIDED BY SOUTHERN EXTENT OF MAIN UPPER TROUGH WORKING THROUGH THE NORTHERN PLAINS. WITH CURRENT FORECAST SPEED OF TROUGH AND SURFACE BOUNDARY...STORMS SHOULD CLEAR MOST OF THE AREA BY 00Z THOUGH WILL HOLD ONTO A CHANCE EAST OF HIGHWAY 60 INTO THE EVENING SHOULD SYSTEM SLOW DOWN A BIT. EARLIER PROJECTED DRY AND COOLER DAY FOR WEDNESDAY STILL ON SCHEDULE BEHIND COLD FRONT...AS HIGH PRESSURE MOVES INTO THE NORTHERN PLAINS. UPPER RIDGING UNANIMOUSLY PROGGED TO RETURN LATER IN THE WEEK WITH A SLOW INCREASE IN TEMPERATURES AND HUMIDITY AS SURFACE HIGH MOVES EAST OF OUR AREA. THE MAIN QUESTION IS HOW LONG IT WILL TAKE FOR A THUNDERSTORM THREAT TO RETURN. WILL GO WITH A SLIGHT CHANCE PROJECTED BY GUIDANCE FOR WEDNESDAY NIGHT FAR WEST AS WARM ADVECTION QUICKLY BEGINS. OTHERWISE IT LOOKS LIKE FRIDAY WILL BE THE RETURN DAY. THE THREAT MAY THEN DECREASE FOR SATURDAY AS THE UPPER RIDGE BUILDS INTO OUR AREA. IN ANY EVENT WIDESPREAD PRECIPITATION SEEMS UNLIKELY WHILE OUR LITTLE SHOT OF RELATIVELY COOL DRY WEATHER IS FOLLOWED BY ANOTHER WARM UP. HOWEVER IT DOES NOT LOOK LIKE A RETURN TO LAST SUMMERS HEAT WAVE. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 1231 PM CDT SUN JUL 7 2013 MAINLY VFR CONDITIONS EXPECTED THROUGH THE PERIOD. MAY SEE A FEW ISOLATED STORMS FIRE THIS AFTERNOON AND EVENING...GENERALLY IN THE VICINITY OF INTERSTATE 90 OR NORTH...AND EAST OF INTERSTATE 29. WILL LEAVE OUT OF TAFS FOR NOW...SINCE COVERAGE IS EXPECTED TO BE LOW...AND BEST CHANCE IS EAST OF TAF SITES. A FEW SHOWERS AND STORMS MAY TRY TO MOVE INTO AREAS WEST OF THE JAMES RIVER THIS EVENING INTO THE OVERNIGHT. BUT THE CHANCE OF THIS IS TOO LOW TO INCLUDE IN THE KHON TAF AT THIS TIME. BRIEF REDUCTIONS TO MVFR OR IFR WILL BE POSSIBLE IN ANY THUNDERSTORM. IF SKIES CLEAR TONIGHT...COULD BE SOME PATCHY AREAS OF MVFR FOG LIKE LAST NIGHT...WILL NOT PUT ANY MENTION IN THE TAFS FOR NOW. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ UPDATE...CHENARD SHORT TERM... LONG TERM... AVIATION...CHENARD
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1056 AM CDT SUN JUL 7 2013 .UPDATE... ISSUED AT 1054 AM CDT SUN JUL 7 2013 INTERESTING FORECAST FOR TODAY. WEAK UPPER WAVE GENERATING AN AREA OF ELEVATED SHOWERS AND STORMS ACROSS CENTRAL SOUTH DAKOTA THIS MORNING. AS THIS WAVE MOVES EAST OUR CWA WILL SEE WEAK UPPER FORCING FOR ASCENT. EXPECT CIRRUS FROM THIS ACTIVITY TO WORK ITS WAY INTO OUR WESTERN CWA AS WE HEAD INTO THIS AFTERNOON. MEANWHILE FRONTAL BOUNDARY IS TAKING ITS SLOW TIME MOVING SOUTH ACROSS OUR CWA. SO QUESTION BECOMES WHAT ARE OUR CONVECTION CHANCES THIS AFTERNOON. A COUPLE THINGS TO WATCH WILL BE DEWPOINT EVOLUTION AND CONVECTIVE EVOLUTION ACROSS CENTRAL AND WESTERN SOUTH DAKOTA. MOISTURE POOLING BEHIND THE FRONT IS CURRENTLY ALLOWING DEWPOINTS TO CREEP INTO THE LOW 70S IN SPOTS. A LOT OF GUIDANCE SUGGEST THESE DEWPOINTS MAY STRUGGLE TO MIX OUT...WITH RELATIVELY DEEP MOISTURE PRESENT UP TO ABOUT 850 MB...AND WEAK FLOW. AS TEMPERATURES RISE INTO THE 80S THIS AFTERNOON...MLCAPE COULD END UP IN THE 2000 TO 3000 J/KG RANGE IN THE AREA OF MOISTURE POOLING. CIN WOULD ALSO BECOME ALMOST ZERO. HOWEVER A VERY DRY LAYER AROUND 700 MB WILL LIKELY HINDER UPDRAFTS SOMEWHAT...AND DESPITE THE BOUNDARY NEARBY...SEE VERY LITTLE IN THE WAY OF LOW LEVEL CONVERGENCE OR FORCING FOR ASCENT. SO IT WOULD COME DOWN TO WHETHER THE INSTABILITY AND WEAK UPPER FORCING WOULD BE ENOUGH TO GET DEEP CU THROUGH THE DRY AIR. HI RES GUIDANCE...SUCH AS THE 06Z WRF ARW AND 12Z 4KM NAM BOTH SUGGEST THIS MAY HAPPEN. THUS WENT AHEAD AND ADDED IN A SLIGHT CHANCE OF STORMS THIS AFTERNOON AND EVENING ACROSS PORTIONS OF OUR CWA. AGAIN THIS IS REALLY DEPENDENT ON IF WE CAN KEEP DEWPOINTS IN THE LOWER 70S. IF THEY FAIL TO MATERIALIZE...THEN DRY AIR ALOFT AND WARM LAYER BETWEEN 800 AND 600 MB WILL LIKELY BE ENOUGH TO CAP CONVECTION. WIND SHEAR IS WEAK...THUS ANY STORM WOULD BE PULSE OR POSSIBLY MULTICELL TYPE. BUT GIVEN WHAT WOULD BE HIGH INSTABILITY...WOULD EXPECT AT LEAST THE THREAT OF QUARTER SIZE HAIL AND 60 MPH WIND GUSTS IN ANY STORM. HRRR DEVELOPS CONVECTION IN CENTRAL SOUTH DAKOTA THIS AFTERNOON...AND MOVES IT INTO OUR WESTERN CWA LATER THIS AFTERNOON AND EVENING. GIVEN EXTENSIVE CLOUD COVER IN THIS AREA...FEEL SURFACE BASED INITIATION IN CENTRAL SOUTH DAKOTA IS UNLIKELY THIS AFTERNOON...THUS BELIEVE THE HRRR SOLUTION IS PROBABLY NOT ACCURATE...AND SO WILL HOLD OFF ON ADDING IN ANY POPS IN OUR WEST THROUGH 0Z. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 430 AM CDT SUN JUL 7 2013 TODAY AND MUCH OF TONIGHT SHOULD REMAIN QUIET IN OUR AREA DESPITE MESSY...WAVE-RIDDLED MID LEVEL FLOW PATTERN BETWEEN DOMINANT RIDGE BUILDING WESTWARD ACROSS THE SOUTHERN CONUS AND VARIOUS TROUGHS TRACKING EASTWARD THROUGH THE CANADIAN PRAIRIES. IN THE NEAR TERM... SEEING SOME ACCAS AND SPOTTY SHOWERS DEVELOP IN WESTERN IOWA AHEAD OF WEAK WAVE. SHOWERS ARE NOT EXPECTED TO IMPACT OUR FORECAST AREA THIS MORNING THOUGH COULD SEE A LITTLE OF THE ACCAS IN OUR FAR EAST EARLY BEFORE WEAK WAVE PASSES BY. WEAK SURFACE BOUNDARY STILL WEST OF I-29 AS OF 08Z MOVING SOUTHEAST MORE SLOWLY THAN EXPECTED AT THIS TIME YESTERDAY...THOUGH STILL EXPECTED TO MAKE SOME EASTWARD PROGRESS THROUGH THE DAY...REACHING NEAR/JUST EAST OF HIGHWAY 60 CORRIDOR IN NORTHWEST IOWA BY LATE AFTERNOON. WITH WEAK LOW LEVEL FLOW...EXPECT HIGHER MOISTURE LEVELS TO POOL NEAR THE BOUNDARY...WITH DEW POINTS IN NORTHWEST IOWA NEAR 70 WHILE TEMPERATURES CLIMB INTO THE LOWER 90S THIS AFTERNOON. THIS SHOULD LEAD TO FAIR AMOUNT OF INSTABILITY WHICH COULD POP A STRAY STORM OR TWO WITH WEAK CONVERGENCE ALONG THE BOUNDARY TOWARD EVENING. WILL HANG ONTO SLIGHT CHANCE FOR NOW...BUT IF SOME HIGH RES MODELS SUCH AS RAP/HRRR TURN OUT TO BE ACCURATE IN THEIR DEPICTION OF DEW POINTS MIXING MUCH LOWER THAN EXPECTED ACROSS OUR SOUTHEAST THIS AFTERNOON...THEN CAP WOULD BE STRONGER AND WOULD NOT SEE ANY DEVELOPMENT. WILL BE SOMETHING TO WATCH THROUGH THE DAY. LATER TONIGHT...WILL BE LOOKING WESTWARD FOR POTENTIAL OF HIGH PLAINS CONVECTION TO WORK TOWARD OUR WESTERN COUNTIES. STILL FAIR AMOUNT OF INSTABILITY FOR STORMS TO WORK WITH AS THEY PUSH TOWARD THE MISSOURI VALLEY AFTER MIDNIGHT. WILL CONTINUE TO CARRY CHANCE INTO AREAS ALONG AND WEST OF THE JAMES VALLEY. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 430 AM CDT SUN JUL 7 2013 IF STORMS DO WORK INTO THE WEST LATE TONIGHT...SHOULD SEE THEM LINGER INTO THE MORNING HOURS ACROSS OUR WEST AND WILL HANG ONTO CHANCE WEST OF I-29 FOR NOW. HOWEVER THIS PERIOD COULD JUST AS LIKELY BE DRY...AS SOME MODELS INDICATING HIGH PLAINS CONVECTION WILL NOT SURVIVE THIS FAR EAST. ALL-IN-ALL...LOW CONFIDENCE IN PRECIP CHANCES ACROSS OUR WEST LATE TONIGHT/MONDAY MORNING. CONFIDENCE SOMEWHAT HIGHER THAT WE WILL SEE DEVELOPMENT ACROSS OUR SOUTH BY MID-LATE AFTERNOON MONDAY... AS WARM FRONT LIFTS BACK TO NEAR THE MISSOURI RIVER VALLEY AND MID LEVEL HEIGHTS COLLAPSE IN ADVANCE OF APPROACHING WAVE. WITH LITTLE FLOW NEAR THE BOUNDARY...SHOULD CONTINUE TO SEE LOW LEVEL MOISTURE BUILD AND ENHANCE INSTABILITY. ALSO START TO SEE BETTER DEEP LAYER SHEAR WORK INTO THE REGION...LOCALLY ENHANCED ALONG THE BOUNDARY. FOR THIS REASON...MONDAY AFTERNOON/EVENING LOOKS TO HAVE FAIR POTENTIAL FOR SEVERE STORMS AS WAVE /IN SOME MODELS/ SLIDES NORTHEAST ACROSS THE FRONTAL BOUNDARY. EVOLUTION OF PRECIP BEYOND THIS SOMEWHAT MUDDLED BY POTENTIAL FOR LINGERING OUTFLOW BOUNDARIES...BUT GENERALLY EXPECT MOST MONDAY NIGHT ACTIVITY TO WORK EAST OF THE FORECAST AREA BY EARLY TUESDAY. COLD FRONT WILL BE PUSHING SOUTHEAST THROUGH THE FORECAST AREA TUESDAY AFTERNOON...AND EXPECT STRONG WARMING INTO THE LOWER TO MID 90S IN THERMAL RIDGE AHEAD OF THE FRONT. HUMIDITY LINGERS AS WELL...WITH DEW POINTS IN THE LOWER OR EVEN MID 70S POSSIBLE ACROSS MUCH OF THE AREA. THIS WILL GIVE FRONT PLENTY OF INSTABILITY TO FEED ON...WITH STORM DEVELOPMENT AIDED BY SOUTHERN EXTENT OF MAIN UPPER TROUGH WORKING THROUGH THE NORTHERN PLAINS. WITH CURRENT FORECAST SPEED OF TROUGH AND SURFACE BOUNDARY...STORMS SHOULD CLEAR MOST OF THE AREA BY 00Z THOUGH WILL HOLD ONTO A CHANCE EAST OF HIGHWAY 60 INTO THE EVENING SHOULD SYSTEM SLOW DOWN A BIT. EARLIER PROJECTED DRY AND COOLER DAY FOR WEDNESDAY STILL ON SCHEDULE BEHIND COLD FRONT...AS HIGH PRESSURE MOVES INTO THE NORTHERN PLAINS. UPPER RIDGING UNANIMOUSLY PROGGED TO RETURN LATER IN THE WEEK WITH A SLOW INCREASE IN TEMPERATURES AND HUMIDITY AS SURFACE HIGH MOVES EAST OF OUR AREA. THE MAIN QUESTION IS HOW LONG IT WILL TAKE FOR A THUNDERSTORM THREAT TO RETURN. WILL GO WITH A SLIGHT CHANCE PROJECTED BY GUIDANCE FOR WEDNESDAY NIGHT FAR WEST AS WARM ADVECTION QUICKLY BEGINS. OTHERWISE IT LOOKS LIKE FRIDAY WILL BE THE RETURN DAY. THE THREAT MAY THEN DECREASE FOR SATURDAY AS THE UPPER RIDGE BUILDS INTO OUR AREA. IN ANY EVENT WIDESPREAD PRECIPITATION SEEMS UNLIKELY WHILE OUR LITTLE SHOT OF RELATIVELY COOL DRY WEATHER IS FOLLOWED BY ANOTHER WARM UP. HOWEVER IT DOES NOT LOOK LIKE A RETURN TO LAST SUMMERS HEAT WAVE. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 638 AM CDT SUN JUL 7 2013 ISOLATED PATCHES OF 3-5SM BR WILL DISSIPATE BY 14Z. OTHERWISE GENERA LY VFR THROUGH 08/09Z. ISOLATED TSRA EAST AND SOUTH OF FSD 07/00Z-06Z AND WEST OF MHE/HON 08/06Z-12Z WITH VERY LOCAL AND BRIEF LOWERING OF CEILINGS TO 2-3K FEET AND VISIBILITIES TO 3-5SM IN TSRA. EXPECTED COVERAGE OF CONVECTION TOO LIGHT TO INCLUDE IN TAFS AT THIS TIME ESPECIALLY SINCE ALL IS EXPECTED AFTER 08/00Z. AFT 08/09Z LCL VISIBILITIES 3-5SM/BR POSSIBLE BUT AGAIN EXPECTED TO BE VERY PATCHY SO NOT AT THIS TIME INCLUDED IN TAF FORECASTS. $$ SHORT TERM... LONG TERM... && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ UPDATE...CHENARD SHORT TERM... LONG TERM... AVIATION...
AREA FORECAST DISCUSSION
NWS MIDLAND/ODESSA TX
630 PM CDT MON JUL 8 2013 .DISCUSSION... SEE AVIATION DISCUSSION BELOW. && .AVIATION... VFR CONDITIONS WITH LIGHT WINDS GUSTING IN THE AFTERNOON THROUGH THE NEXT 24 HOURS. && .PREV DISCUSSION... /ISSUED 229 PM CDT MON JUL 8 2013/ DISCUSSION... AN UPPER LEVEL DISTURBANCE PASSING BY TO THE SOUTH ACROSS THE BIG BEND COULD GENERATE ISOLATED THUNDERSTORMS THIS EVENING ACROSS WEST TEXAS PER CUMULUS FIELD AND LATEST RUC GUIDANCE. ANY ACTIVITY SHOULD DIE THIS EVENING WITH LOSS OF HEATING. THIS DISTURBANCE IS FORECAST TO CONTINUE TO SLOWLY TRACK WESTWARD ACROSS NORTHERN MEXICO TUESDAY AND TUESDAY EVENING WITH ISOLATED TO WIDELY SCATTERED SHOWERS AND THUNDERSTORMS POSSIBLE AGAIN ACROSS THE BIG BEND...DAVIS MOUNTAINS AND LOWER TRANS PECOS REGION CLOSEST TO THE TRACK OF DISTURBANCE. BEYOND TUESDAY A SPRAWLING UPPER LEVEL HIGH PRESSURE AREA ACROSS THE PLAINS AND ROCKIES SHOULD REGAIN FIRM CONTROL OF THE REGION AND PRECIPITATION CHANCES WILL BE VERY LOW. THE NEXT CHANCE OF CONVECTION APPEARS TO BE NEXT SUNDAY AND MONDAY AS ANOTHER DISTURBANCE TRACKS WESTWARD ACROSS THE GULF AND MEXICO. HIGH TEMPERATURES ARE EXPECTED TO BE NEAR NORMAL THROUGH WEDNESDAY WITH ABOVE NORMAL TEMPERATURES EXPECTED THURSDAY THROUGH SATURDAY. && .MAF WATCHES/WARNINGS/ADVISORIES... NM...NONE. TX...NONE. && $$ 10
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
344 PM CDT SUN JUL 7 2013 .SHORT TERM... A FLATTENED AND QUASI-ZONAL UA RIDGE HAS SHIFTED TO THE SOUTHERN PLAINS...WITH THE CENTER DRAPED FROM THE SOUTHERN PLAINS TO WRN NM. A PLUME OF PACIFIC MOISTURE CONTINUED TO SPILL ACROSS THE CWA RESULTING IN FEW-SCT HIGH LEVEL CLOUDINESS. MID-UPPER LEVEL THICKNESS VALUES ARE SLIGHTER LOWER THAN YESTERDAY DURING THIS TIME...BUT WARM TEMPS STILL PREVAILED WITH HIGHS IN THE UPPER 80S TO LOWER 90S ON THE CAPROCK TO LOWER TO MID 90S OFF THE CAPROCK A SFC TROUGH WAS LOCATED FROM SWRN KS TO SOUTH CENTRAL NM...THOUGH THE PRESSURE GRADIENT WAS NOT AS STRONG AS PREVIOUS DAYS AND THUS SRLY WIND SPEEDS WERE NOT OVERLY BREEZY LATE THIS AFTN /10-20 MPH/. THE CO-EXISTENCE OF THE AFOREMENTIONED SFC TROUGH WITH THE BEST THETA-E AXIS...IN ADDITION TO OROGRAPHIC INFLUENCES AND DAYTIME DESTABILIZATION...CAUSED THE DEVELOPMENT OF SHOWERS AND THUNDERSTORMS ACROSS THE HIGHER MOUNTAINOUS TERRAIN OF ERN NM AND SERN CO. WITH THE UA RIDGE TAKING UP RESIDENCE ACROSS THE SOUTHERN PLAINS...STEERING FLOW IS RATHER WEAK WHICH WILL MAKE MOUNTAINOUS AREA STORMS HARD PRESSED TO REACH THE FA /THIS HAS BEEN THE CASE THE PAST FEW DAYS/. HOWEVER...A FEW ELEVATED LIGHT SHOWERS HAVE DEVELOPED ACROSS THE FAR SWRN TEXAS PANHANDLE...COINCIDING WITH ADEQUATE ALBEIT WEAK MID-LEVEL MOISTURE CONVERGENCE. THE RUC HAS PICKED UP ON THIS SIGNAL WITH HINTS OF IT EXPANDING TO THE NWRN ZONES LATER THIS AFTN...BEFORE WANING AOA SUNSET. THE PLUME OF PACIFIC MOISTURE TRAPPED BENEATH THE RIDGE WILL ENSUE TONIGHT...ALTHOUGH IT IS PROGGED TO THIN AND BE CONFINED TO THE WRN PANHANDLES AND FAR NWRN ZONES. MID-LEVEL ASCENT ACROSS THE SAID AREA ARE NOT THAT IMPRESSIVE...BUT MODELS DO EXHIBIT LIGHT QPF SIGNALS NEAR THE TX/NM BORDER OR JUST WEST OF THE CWA. DUE TO RECENT NIGHTS OF NOCTURNAL ACTIVITY...WILL GO AHEAD AND RAISE POPS TO MENTIONABLE LEVELS ACROSS THE FAR NWRN ZONES. WEAKENED OVERNIGHT LLJ EQUATES RELATIVELY LIGHT SERLY SFC WINDS...BUT MILD TEMPS ARE STILL ANTICIPATED /MID 60S NW TO 70S EAST/. TOMORROW...UA RIDGING AND WARM TEMPS WILL ENSUE /LOW TO MID 90S ON THE CAPROCK TO MID UPPER 90S OFF THE CAPROCK/ THOUGH THE CENTER OF THE RIDGE WILL RETROGRADE TO AZ/NM WHILST A GULF OF MEXICO WEAKNESS TREKS WNW ACROSS SRN TX. NOT EXPECTING THIS WEAKNESS TO PROVIDE THE CWFA WITH ANY MAJOR CHANGES WITH REGARD TO SENSIBLE WX...WITH THE EXCEPTION OF DEWPOINTS INCREASING INTO THE LOW 60S AND NEARING MID-LEVEL CLOUDINESS FOR THE FAR SERN ZONES. PLUME OF PACIFIC MOISTURE WILL ALSO SHIFT WEST TO MORE SO ACROSS NM WHERE BEST PRECIP CHANCES WILL RESIDE. /29 && .LONG TERM... FEW CHANGES ONCE AGAIN THIS FORECAST PACKAGE...AS THE LARGE UPPER LEVEL HIGH PRESSURE RIDGE WILL DOMINATE OUR WEATHER THROUGH THE WEEK AND LIKELY THE WEEKEND AS WELL. PRECIPITATION SIGNALS THIS COMING WEEK ARE HARD TO COME BY...THOUGH ONE WE ARE SEEING CONSISTENTLY IS IN THE LATE WEDNESDAY AND EARLY THURSDAY TIME- FRAME AS A WAVE DIGS INTO THE NORTHERN GREAT LAKES WITH A WEAKENING SURFACE FRONTAL BOUNDARY LURCHING SLOWLY SOUTHWARD. THE LATEST RUNS DO NOT APPEAR TO WEAKEN THE RIDGE VERY MUCH AND STEERING FLOW SHOULD REMAIN VERY WEAK. BUT SOLUTIONS HAVE BEEN PAINTING THUNDER DEVELOPMENT NEAR THIS BOUNDARY ACROSS THE TEXAS PANHANDLE INTO WESTERN OKLAHOMA...AND EVEN VERY NEAR THE RED RIVER BY EARLY THURSDAY. BULK OF SOLUTIONS...HOWEVER...APPEAR TO BOUND THE ACTIVITY JUST TO THE NORTH AND EAST OF THE NORTHERN ROLLING PLAINS. WE WILL RETAIN THE JUST SUB-MENTIONABLE LEVEL OF PRECIPITATION UNTIL WE SEE MORE SIGNALS WITHIN OUR AREA. FOLLOWING THIS WAVE...THE UPPER RIDGE STILL APPEARS TO SPRING BACK TO THE NORTH AND EAST...CENTERED JUST TO OUR NORTH FOR THE END OF THE WEEK INTO THE EARLY WEEKEND. THIS STILL SHOULD ACCOUNT FOR SLIGHTLY HOTTER TEMPERATURES AND WE HAVE BOOSTED HIGHS A DEGREE OR TWO ABOVE THE PREVIOUS FORECAST. FINALLY...BY LATE IN THE WEEKEND THE RIDGE IS EXPECTED TO RETROGRADE TO OUR WEST AS A SOUTHWESTWARD MOVING UPPER LOW TRAVERSES THE DEEP SOUTH PERHAPS CROSSING WEST OF THE MISSISSIPPI BY MONDAY. LOTS OF QUESTIONS ABOUT THIS PATTERN... THOUGH SOME LEVEL OF COOLING ALONG WITH A MOISTURE INCREASE SEEM FAIRLY CERTAIN. MOST OF THE REAL CHANGES... HOWEVER...WILL BE IN DAY 8 AND BEYOND. STAY TUNED. RMCQUEEN && .PRELIMINARY POINT TEMPS/POPS... FRIONA 66 93 67 95 67 / 20 10 10 10 10 TULIA 66 95 69 97 69 / 10 10 10 10 10 PLAINVIEW 67 93 69 96 69 / 10 10 10 10 10 LEVELLAND 67 94 68 94 68 / 10 10 10 10 10 LUBBOCK 69 96 70 96 70 / 10 10 10 10 10 DENVER CITY 68 94 67 93 67 / 10 10 10 10 10 BROWNFIELD 69 94 67 95 68 / 10 10 10 0 10 CHILDRESS 70 98 73 100 74 / 0 0 0 0 10 SPUR 70 97 71 97 71 / 0 0 0 0 10 ASPERMONT 71 98 72 100 73 / 0 0 0 0 0 && .LUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 29/05
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
1242 PM CDT SUN JUL 7 2013 .AVIATION... WITH OVERALL POP BEING ABOUT 20 PERCENT THIS AFTERNOON ACROSS THE I-35 CORRIDOR...HAVE REMOVED MENTION OF SH/TS IN THE SHORT TERM IN THE AUS/SAT/SSF TAFS. SEABREEZE ACTIVITY IS EXPECTED TO FIRE UP TO THE SOUTHEAST THIS AFTERNOON BUT STILL QUESTIONABLE WHETHER IT WILL MAKE IT THIS FAR INLAND. SCT CLOUDS EXPECTED ALTHOUGH FOR THE REMAINDER OF THE AFTERNOON COULD SEE SOME CIG DECKS FROM TIME TO TIME BUT SHOULD BE AROUND 5KFT OR SO. WITH PRECIPITABLE WATER INCREASING TO OVER 2 INCHES TOMORROW...HAVE INPUT SOME VCSH FOR THE MORNING HOURS AND ADDED A PROB30 GROUP IN THE 30 HOUR TAFS OF AUS/SAT FOR THE POSSIBILITY OF AFTERNOON SHOWERS AND STORMS. SOME MVFR CIGS ARE ONCE AGAIN EXPECTED IN THE EARLY-LATE MORNING. CLOUDS SHOULD BE A BIT MORE NUMEROUS ON MONDAY ESPECIALLY IN THE AFTERNOON WITH THE DEEPER MOISTURE AND DEBRIS CLOUDS FROM NEARBY CB. LEFT DRT TAF DRY FOR NOW AS CONFIDENCE IS LOW ON HOW FAR WEST THE MOISTURE WILL PUSH BY 18Z MON. AM THINKING BEST CHANCES FOR DRT WILL OCCUR LATER ON MON AFTERNOON AND MON NIGHT. && .PREV DISCUSSION... /ISSUED 1051 AM CDT SUN JUL 7 2013/ UPDATE... MINOR ADJUSTMENTS TO FIRST PERIOD. DISCUSSION... MORNING SOUNDINGS INDICATE PW VALUES HAVE INCREASED BY .25 TO .5 INCHES ACROSS THE AREA AS COMPARED TO 24 HRS AGO. MOISTURE WILL CONTINUE TO INCREASE AS THE UPPER LOW IN THE NWRN GULF PROGRESSES ONSHORE LATER TODAY. ISOLATED SHOWERS AND THUNDERSTORMS HAVE PUSHED INTO THE COASTAL PLAINS THIS MORNING...AND SHOULD INCREASE IN COVERAGE ONCE DIURNAL HEATING BECOMES A FACTOR. ONGOING FORECAST IS GENERALLY ON TRACK. ONLY MINOR ADJUSTMENTS WERE MADE TO FIRST-PERIOD POPS/WX/QPF AND TEMPERATURES. NEW ZONES WILL BE OUT SHORTLY. PREV DISCUSSION... /ISSUED 641 AM CDT SUN JUL 7 2013/ UPDATE... SEE AVIATION FOR 12Z TAF DISCUSSION. AVIATION... A TROPICAL AIR MASS AND A MOSTLY ELEVATED LOW PRESSURE TROUGH MOVING INTO THE TX COAST WILL DISRUPT THE OCCASIONAL MVFR CIG THIS MORNING. WITH LIGHT WINDS AND BUOYANT AIR IN THE AREA...SCT LOW BASED CUMULUS OF AROUND 1500 FT WILL HAVE TOPS LIFTING TO 10000 FT OR HIGHER AS LIGHT SHOWERS BEGIN TO MOVE TOWARD THE I-35 TERMINALS. WILL LEAVE OUT MENTION OF MVFR CIGS UNTIL THE BETTER CHANCE OF RAINS ARRIVE IN THE EARLY AFTERNOON HOURS AS DEPICTED BY THE HRRR SIMULATED REFLECTIVITY. ANY FEEBLE ATTEMPT TO DEVELOP A SURFACE CIRCULATION EAST OF BRO SHOULD BE HELD IN CHECK AS THE UPPER SUPPORT PUSHES ONSHORE BY TONIGHT. THUS WILL PLAN ON A MORE STEADY ONSHORE WIND BY TONIGHT...AND A MORE ROUTINE FORMATION OF LOW CLOUDS AT AROUND 09Z. HIGH PWAT VALUES COULD SUPPORT ADDITIONAL SHOWERS AROUND DAYBREAK...BUT WILL LEAVE OUT OF THE LATE PERIODS OF THE TAFS UNTIL A BETTER TREND CAN BE ESTABLISHED. PREV DISCUSSION... /ISSUED 322 AM CDT SUN JUL 7 2013/ SHORT TERM (TODAY THROUGH MONDAY)... A WEAKENED UPPER LEVEL INVERTED TROUGH FEATURE OVER THE WESTERN GULF OF MEXICO WILL MIGRATE WEST ONTO THE TEXAS COASTAL PLAINS REGION TODAY WITH AN ENHANCEMENT OF SEA BREEZE ACTIVITY LIKELY OVER SOUTHERN AND EASTERN PORTIONS OF THE CWA. HIGH TEMPERATURES TODAY WILL LOWER SLIGHTLY WITH THE INCREASING SURFACE BASED MOISTURE. HIGHS TODAY WILL RANGE FROM THE LOW 90S ACROSS PORTIONS OF THE HILL COUNTRY TO THE MID TO UPPER 90S ELSEWHERE. INCREASING CLOUDINESS TONIGHT WITH A SLIGHT CHANCE OF MOSTLY EARLY EVENING SHOWERS AND STORMS SOUTH AND EAST. LOWS IN THE 70S. THE UPPER TROUGH WILL MOVE ACROSS THE AREA MONDAY WITH DEEP...MOIST TROPICAL EASTERLIES BRINGING A CHANCE OF SHOWERS AND THUNDERSTORMS THROUGHOUT MUCH OF THE AREA. HIGHS MONDAY WILL MODERATE BACK INTO THE LOWER 90S MOST LOCATIONS WITH NEAR 90 HILL COUNTRY. LONG TERM (MONDAY NIGHT THROUGH SATURDAY)... SHOWERS AND STORMS WILL DIMINISH MONDAY EVENING AS THE INVERTED UPPER TROUGH PUSHES DEEPER INTO MEXICO. LOWS MONDAY NIGHT AGAIN MOSTLY IN THE 70S WITH NEAR 70 HILLS. UPPER LEVEL RIDGING WILL BUILD BACK OVER THE REGION TUESDAY AND REMAIN STRONG THROUGH SATURDAY AS THE CENTER OF THE HIGH SHIFTS EAST INTO THE SOUTHERN PLAINS BY LATE IN THE WEEK. CONTINUED DEEP EASTERLIES HOWEVER IN THE MID AND LOWER LEVELS OF THE ATMOSPHERE WILL ENHANCE SOME SEA BREEZE CONVECTION INTO EASTERN SECTIONS BOTH TUESDAY AND WEDNESDAY. MORNING LOW CLOUDS WILL BECOME PARTLY CLOUDY AFTERNOONS BOTH DAYS WITH HIGHS RANGING FROM THE LOW 90S HILLS TO THE UPPER 90S TO NEAR 100 EASTERN SECTIONS. LOWS IN THE 70S. ANOTHER EASTERLY WAVE FEATURE PUSHING ACROSS THE COASTAL PLAINS THURSDAY WILL GENERATE MORE ACTIVITY OVER EASTERN SECTIONS BOTH THURSDAY AND FRIDAY. HIGHS WILL CONTINUE NEAR OR SLIGHTLY ABOVE SEASONAL NORMS THURSDAY THROUGH SATURDAY. LOWS GENERALLY IN THE 70S EXCEPT UPPER 60S TO NEAR 70 HILLS. && .PRELIMINARY POINT TEMPS/POPS... AUSTIN CAMP MABRY 97 75 94 74 100 / 20 20 20 10 - AUSTIN BERGSTROM INTL AIRPORT 96 74 93 72 99 / 20 20 30 10 - NEW BRAUNFELS MUNI AIRPORT 95 73 93 72 96 / 20 20 30 10 10 BURNET MUNI AIRPORT 94 74 91 73 96 / 10 10 20 10 - DEL RIO INTL AIRPORT 97 76 92 75 94 / - - 30 20 10 GEORGETOWN MUNI AIRPORT 95 74 93 72 98 / 20 10 20 10 - HONDO MUNI AIRPORT 96 74 90 73 96 / 20 10 30 20 - SAN MARCOS MUNI AIRPORT 96 74 93 73 97 / 20 20 30 10 10 LA GRANGE - FAYETTE REGIONAL 94 76 92 75 99 / 40 20 30 10 20 SAN ANTONIO INTL AIRPORT 94 76 91 75 96 / 20 20 30 10 - STINSON MUNI AIRPORT 95 74 92 73 94 / 20 20 30 10 - && .EWX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ MESOSCALE/AVIATION...09 SYNOPTIC/GRIDS...25 PUBLIC SERVICE/DATA COLLECTION...33
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1221 PM CDT SUN JUL 7 2013 .AVIATION... VFR CONDITIONS WILL PREVAIL THROUGHOUT THE TAF PERIOD. SLIGHTLY BREEZY SRLY WINDS /10-12 KTS/ WILL DECLINE FURTHER SHORTLY AFTER SUNSET. FEW-SCT CLOUD DECKS THIS AFTN WILL BECOME SKC OVERNIGHT THROUGH TOMORROW. && PREV DISCUSSION... /ISSUED 343 AM CDT SUN JUL 7 2013/ SHORT TERM... DIRTY SOUTHWESTERN RIDGE HAS EXPANDED TO ENCOMPASS WEST TEXAS AND THIS WILL PROVIDE ANOTHER TOASTY JULY DAY WITH HIGHS SIMILAR TO SATURDAY. MID-LEVEL MOISTURE SPILLING OVER THE SOUTH PLAINS COUPLED WITH WEAK ELEVATED INSTABILITY...DEEP LAYER MOISTURE CONVERGENCE AND ELEVATED FRONTOGENESIS WERE SUPPORTING A FEW RECENTLY DEVELOPED SHOWERS AND STORMS ACROSS THE FAR NORTHWESTERN ZONES. THIS ACTIVITY WAS NOT MOVING MUCH THANKS TO WEAK STEERING FLOW/WINDS WITHIN THE RIDGE...BUT WE COULD SEE AT LEAST ISOLATED ACTIVITY HANG ON ACROSS THE WESTERN ZONES AND PERHAPS EXPAND/DEVELOP TOWARD THE I-27/US-87 CORRIDOR AS THE RECENT RAP AND HRRR RUNS SUGGEST. HENCE HAVE INSERTED A SLIGHT CHANCE OF THUNDERSTORMS INTO THE GRIDS ACROSS THE WESTERN AND INTO THE CENTRAL ZONES IN THE 12-18Z TIME-FRAME. ANY ACTIVITY WILL LIKELY WANE TOWARD MID TO LATE MORNING. STRONG HEATING AND SUFFICIENT MOISTURE WILL THEN YIELD ANOTHER ROUND OF CONVECTION OVER THE HIGHER TERRAIN OF NM AND CO THIS AFTERNOON...BUT SIMILAR TO SATURDAY...THIS ACTIVITY WILL NOT HAVE MUCH INCENTIVE TO MOVE VERY FAR EASTWARD AND SHOULD STAY WELL WEST OF THE CWA. THE MID-LEVEL MOISTURE PLUME WILL STILL EXTEND IN CLOSE PROXIMITY TO THE FAR NORTHWESTERN ZONES LATE TONIGHT AND THERE MAY BE SOME RISK OF LATE NIGHT ELEVATED CONVECTIVE DEVELOPMENT LIKE WE HAVE SEEN THE LAST COUPLE OF NIGHTS. HOWEVER THE MID-LEVEL MOISTURE PLUME IS PROGGED TO THIN/DRY A BIT LOCALLY AND LOW-LEVEL FORCING APPEARS LESS...SO HAVE KEPT THE FORECAST DRY FOR TONIGHT. OTHERWISE...IT WILL BE ANOTHER MILD NIGHT WITH LOWS VARYING FROM THE MID-60S NORTHWEST TO LOWER AND MIDDLE 70S EAST. LONG TERM... AN UPPER LEVEL RIDGE...CENTERED ROUGHLY OVER THE 4-CORNERS INITIALLY... AND GRADUALLY MIGRATING INTO THE CENTRAL HIGH PLAINS...WILL KEEP THE FA HOT AND DRY FOR THE MOST PART THIS UPCOMING WEEK. OROGRAPHICALLY FORCED CONVECTION WITHIN MOISTURE PLUME TRAPPED IN THE RIDGE SHOULD REMAIN TO OUR WEST MONDAY WHILE AN INVERTED TROUGH MOVING WEST ACROSS THE BIG BEND WILL BE OF LITTLE CONSEQUENCE TO OUR WX. WE ARE STILL WATCHING FOR A TEMPORARY WEAKNESS TO DEVELOP IN THE EASTERN PART OF THE RIDGE WED/THU AS A SHORTWAVE MOVES FROM THE CANADIAN PRAIRIES TO THE GREAT LAKES AND A COLD FRONT DIPS INTO SRN CO/SW KS. BUT ANY TSTM ACTIVITY ASSOCIATED WITH THIS WAVE/FRONT APPEARS UNLIKELY TO MAKE IT INTO OUR NRN ZONES LATE WED/EARLY THU. THEN...AS THE UPPER RIDGE RE- EXPANDS E-NEWD WE EXPECT TEMPS TO NUDGE UPWARD A FEW DEGREES HEADING INTO NEXT WEEKEND. EARLY NEXT WEEK...THE UPPER RIDGE MAY START TO RETROGRADE BACK TO THE WEST AS AN UPPER TROUGH/LOW DEVELOPS IN THE DEEP SOUTH. WE ARE COUNTING ON THIS PATTERN CHANGE TO BRING A COOLING TREND AND PERHAPS A CHANCE OF RAIN NEXT WEEK. && .PRELIMINARY POINT TEMPS/POPS... FRIONA 66 93 66 95 67 / 10 10 10 10 10 TULIA 67 95 68 96 69 / 10 10 10 10 10 PLAINVIEW 67 95 69 95 69 / 10 10 10 10 10 LEVELLAND 68 94 70 94 69 / 10 10 10 10 10 LUBBOCK 70 95 70 95 71 / 10 10 10 10 10 DENVER CITY 68 93 69 93 67 / 10 10 10 10 10 BROWNFIELD 69 94 70 95 69 / 10 10 10 0 10 CHILDRESS 71 98 74 99 75 / 0 0 0 0 10 SPUR 71 96 72 97 72 / 0 0 0 0 10 ASPERMONT 72 97 74 99 75 / 0 0 0 0 0 && .LUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 29
AREA FORECAST DISCUSSION...UPDATED
NWS AUSTIN/SAN ANTONIO TX
1051 AM CDT SUN JUL 7 2013 .UPDATE... MINOR ADJUSTMENTS TO FIRST PERIOD. && .DISCUSSION... MORNING SOUNDINGS INDICATE PW VALUES HAVE INCREASED BY .25 TO .5 INCHES ACROSS THE AREA AS COMPARED TO 24 HRS AGO. MOISTURE WILL CONTINUE TO INCREASE AS THE UPPER LOW IN THE NWRN GULF PROGRESSES ONSHORE LATER TODAY. ISOLATED SHOWERS AND THUNDERSTORMS HAVE PUSHED INTO THE COASTAL PLAINS THIS MORNING...AND SHOULD INCREASE IN COVERAGE ONCE DIURNAL HEATING BECOMES A FACTOR. ONGOING FORECAST IS GENERALLY ON TRACK. ONLY MINOR ADJUSTMENTS WERE MADE TO FIRST-PERIOD POPS/WX/QPF AND TEMPERATURES. NEW ZONES WILL BE OUT SHORTLY. && .PREV DISCUSSION... /ISSUED 641 AM CDT SUN JUL 7 2013/ UPDATE... SEE AVIATION FOR 12Z TAF DISCUSSION. AVIATION... A TROPICAL AIR MASS AND A MOSTLY ELEVATED LOW PRESSURE TROUGH MOVING INTO THE TX COAST WILL DISRUPT THE OCCASIONAL MVFR CIG THIS MORNING. WITH LIGHT WINDS AND BUOYANT AIR IN THE AREA...SCT LOW BASED CUMULUS OF AROUND 1500 FT WILL HAVE TOPS LIFTING TO 10000 FT OR HIGHER AS LIGHT SHOWERS BEGIN TO MOVE TOWARD THE I-35 TERMINALS. WILL LEAVE OUT MENTION OF MVFR CIGS UNTIL THE BETTER CHANCE OF RAINS ARRIVE IN THE EARLY AFTERNOON HOURS AS DEPICTED BY THE HRRR SIMULATED REFLECTIVITY. ANY FEEBLE ATTEMPT TO DEVELOP A SURFACE CIRCULATION EAST OF BRO SHOULD BE HELD IN CHECK AS THE UPPER SUPPORT PUSHES ONSHORE BY TONIGHT. THUS WILL PLAN ON A MORE STEADY ONSHORE WIND BY TONIGHT...AND A MORE ROUTINE FORMATION OF LOW CLOUDS AT AROUND 09Z. HIGH PWAT VALUES COULD SUPPORT ADDITIONAL SHOWERS AROUND DAYBREAK...BUT WILL LEAVE OUT OF THE LATE PERIODS OF THE TAFS UNTIL A BETTER TREND CAN BE ESTABLISHED. PREV DISCUSSION... /ISSUED 322 AM CDT SUN JUL 7 2013/ SHORT TERM (TODAY THROUGH MONDAY)... A WEAKENED UPPER LEVEL INVERTED TROUGH FEATURE OVER THE WESTERN GULF OF MEXICO WILL MIGRATE WEST ONTO THE TEXAS COASTAL PLAINS REGION TODAY WITH AN ENHANCEMENT OF SEA BREEZE ACTIVITY LIKELY OVER SOUTHERN AND EASTERN PORTIONS OF THE CWA. HIGH TEMPERATURES TODAY WILL LOWER SLIGHTLY WITH THE INCREASING SURFACE BASED MOISTURE. HIGHS TODAY WILL RANGE FROM THE LOW 90S ACROSS PORTIONS OF THE HILL COUNTRY TO THE MID TO UPPER 90S ELSEWHERE. INCREASING CLOUDINESS TONIGHT WITH A SLIGHT CHANCE OF MOSTLY EARLY EVENING SHOWERS AND STORMS SOUTH AND EAST. LOWS IN THE 70S. THE UPPER TROUGH WILL MOVE ACROSS THE AREA MONDAY WITH DEEP...MOIST TROPICAL EASTERLIES BRINGING A CHANCE OF SHOWERS AND THUNDERSTORMS THROUGHOUT MUCH OF THE AREA. HIGHS MONDAY WILL MODERATE BACK INTO THE LOWER 90S MOST LOCATIONS WITH NEAR 90 HILL COUNTRY. LONG TERM (MONDAY NIGHT THROUGH SATURDAY)... SHOWERS AND STORMS WILL DIMINISH MONDAY EVENING AS THE INVERTED UPPER TROUGH PUSHES DEEPER INTO MEXICO. LOWS MONDAY NIGHT AGAIN MOSTLY IN THE 70S WITH NEAR 70 HILLS. UPPER LEVEL RIDGING WILL BUILD BACK OVER THE REGION TUESDAY AND REMAIN STRONG THROUGH SATURDAY AS THE CENTER OF THE HIGH SHIFTS EAST INTO THE SOUTHERN PLAINS BY LATE IN THE WEEK. CONTINUED DEEP EASTERLIES HOWEVER IN THE MID AND LOWER LEVELS OF THE ATMOSPHERE WILL ENHANCE SOME SEA BREEZE CONVECTION INTO EASTERN SECTIONS BOTH TUESDAY AND WEDNESDAY. MORNING LOW CLOUDS WILL BECOME PARTLY CLOUDY AFTERNOONS BOTH DAYS WITH HIGHS RANGING FROM THE LOW 90S HILLS TO THE UPPER 90S TO NEAR 100 EASTERN SECTIONS. LOWS IN THE 70S. ANOTHER EASTERLY WAVE FEATURE PUSHING ACROSS THE COASTAL PLAINS THURSDAY WILL GENERATE MORE ACTIVITY OVER EASTERN SECTIONS BOTH THURSDAY AND FRIDAY. HIGHS WILL CONTINUE NEAR OR SLIGHTLY ABOVE SEASONAL NORMS THURSDAY THROUGH SATURDAY. LOWS GENERALLY IN THE 70S EXCEPT UPPER 60S TO NEAR 70 HILLS. && .PRELIMINARY POINT TEMPS/POPS... AUSTIN CAMP MABRY 97 75 94 74 100 / 20 20 20 10 - AUSTIN BERGSTROM INTL AIRPORT 96 74 93 72 99 / 20 20 30 10 - NEW BRAUNFELS MUNI AIRPORT 95 73 93 72 96 / 20 20 30 10 10 BURNET MUNI AIRPORT 94 74 91 73 96 / 10 10 20 10 - DEL RIO INTL AIRPORT 97 76 92 75 94 / - - 30 20 10 GEORGETOWN MUNI AIRPORT 95 74 93 72 98 / 20 10 20 10 - HONDO MUNI AIRPORT 96 74 90 73 96 / 20 10 30 20 - SAN MARCOS MUNI AIRPORT 96 74 93 73 97 / 20 20 30 10 10 LA GRANGE - FAYETTE REGIONAL 94 76 92 75 99 / 40 20 30 10 20 SAN ANTONIO INTL AIRPORT 94 76 91 75 96 / 20 20 30 10 - STINSON MUNI AIRPORT 95 74 92 73 94 / 20 20 30 10 - && .EWX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ MESOSCALE/AVIATION...09 SYNOPTIC/GRIDS...25 PUBLIC SERVICE/DATA COLLECTION...33
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1006 AM CDT SUN JUL 7 2013 .UPDATE... SCATTERED LIGHT SHOWERS TO COME ONSHORE THROUGH THE REMAINDER OF THE MORNING...NO MORE THAN A FEW HUNDREDTHS TO A TENTH OF AN INCH OF ACCUMULATION FROM MANY OF THESE QUICKLY NORTH-PASSING CELLS. AS THE DAY HEATS UP INTO THE 90S...THIS 2 INCH PWAT AIR MASS OVER THE COASTAL COUNTIES WILL CONTINUE TO CREEP FURTHER INLAND SO EXPECTING PRECIPITATION TO BETTER FILL IN THROUGH THE EARLY EVENING. PROG SOUNDINGS SHOW A NEAR-SATURATED COLUMN AS FAR NORTH AS THE CITY BY TOMORROW MORNING. THUS...FEEL THAT AT LEAST HIGH END CHANCE POPS ARE WARRANTED THROUGH TOMORROW AFTERNOON. WARM PROFILES MAKE FOR SKINNY CAPES...LIMITED STORM COVERAGE. RELATIVELY LOWER AREAWIDE (OVERALL) QPF DUE TO THE WIDELY-SCATTERED NATURE ON CONVECTION... LOCALIZED POCKETS OF OVER AN INCH OVER THE SOUTHERN THIRD OF THE CWA IS STILL NOT OUT OF THE QUESTION. 31 && .PREV DISCUSSION... /ISSUED 624 AM CDT SUN JUL 7 2013/ AVIATION... SCATTERED SHOWERS ARE ONGOING ACROSS THE COASTAL COUNTIES THIS MORNING AS THE LEADING EDGE OF DEEP TROPICAL MOISTURE MOVES INLAND. GREATEST CONCERN WITH THIS ISSUANCE REMAINS TIMING AND COVERAGE OF PRECIPITATION TODAY. EXPECT SCATTERED SHOWERS WITH A FEW ISOLATED THUNDERSTORMS MIXED IN ACROSS THE SOUTHERN HALF OF THE REGION. WILL CARRY PROB30 MENTION FOR METRO AREA TAF SITES FOR LATE AFTERNOON AS CONFIDENCE IN TIMING A BIT TOO LOW FOR TEMPO AT THIS TIME. GREATEST IMPACTS WILL BE TO LBX AND GLS WITH DECREASING COVERAGE TO THE NORTH. 38 PREV DISCUSSION... /ISSUED 425 AM CDT SUN JUL 7 2013/ DISCUSSION... LATEST RADAR IMAGERY SHOWS A LINE OF SHOWERS JUST REACHING THE UPPER TX COAST THIS MORNING. THIS LINE OF SHOWERS APPEARS TO BE ON THE LEADING EDGE OF HIGHER MOISTURE DELINEATED BY 2 INCH PRECIP WATER VALUES NOTED ON GOES SOUNDER IMAGERY. UPPER LEVEL ANALYSIS AND WATER VAPOR IMAGERY STILL SHOW A DEFORMING SHEAR AXIS WHICH SEEMS TO BE IN THE PROCESS OF WEAKENING. PRESSURE GRADIENT AT THE SFC HAS INCREASED SO GETTING SOME DECENT LOW LEVEL FLOW OFF THE GULF WHICH SHOULD CONTINUE TO ADVECT HIGHER MOISTURE INLAND TODAY. FOR THE MOST PART...GFS/ECMWF MODELS CONTINUE TO SHOW HIGHER MOISTURE MOVE INTO SE TX THIS MORNING AND THROUGH THE EARLY AFTERNOON. THE LATEST HRRR RUNS SEEMS TO SUPPORT THIS WITH CONVECTION DEVELOPING INLAND MAINLY AROUND 15-16Z AND CONTINUING THROUGH 22-23Z THIS AFTERNOON. ACTIVITY LOOKS MORE SCT IN NATURE SO BACKED OFF ON POPS A TOUCH. STILL HAVE 60 POPS FOR THE I-10 CORRIDOR INCLUDING MOST OF HOUSTON. HEAVY RAINFALL THREAT WILL LARGELY DEPEND ON INDIVIDUAL CELLS THAT BECOME STRONG AND FULLY TAP DEEPER MOISTURE. GFS SHOWS PRECIP WATER VALUES GETTING TO AROUND 2-2.2 INCHES WHICH WILL SUPPORT MODERATE TO HEAVY RAINFALL. AGAIN MAIN FLOOD THREAT WILL BE URBAN IN NATURE WITH STORMS THAT CAN QUICKLY PRODUCE 2 INCHES IN AN HOUR. OTHERWISE DRY GROUNDS SHOULD BE ABLE TO ABSORB A LOT OF THE RUN OFF AND NOT CONTRIBUTE TO FLOODING. WITH MOISTURE SLOWLY PUSHING INTO THE AREA...ALSO INCREASED MAX TEMPS A COUPLE OF DEGREES AS CLOUD COVER WILL BE SLOW TO FILL IN ACROSS THE AREA. LOOK FOR 1.8-2 INCH PW VALUES TO REMAIN OVER SE TX THROUGH MONDAY SO WENT WITH 40/50 POPS FOR SCATTERED ACTIVITY DURING THE DAY. AGAIN MOST OF THIS ACTIVITY WILL BE DIURNALLY DRIVEN SO WILL HAVE LOWER POPS OVERNIGHT. RAINFALL AMOUNTS AGAIN EXPECTED TO BE CONFINED TO THE COAST. HOUSTON AREA MAY GET WIDE SPREAD HALF INCH AMOUNTS BUT THAT WILL BE PUSHING IT. NORTH OF HOUSTON EXPECT RAINFALL AMOUNTS TO REALLY DROP OFF AND AREAS FROM CONROE TO COLLEGE STATION MAY NOT SEE ANY RAINFALL. BY AND LARGE THINK AREAS NORTH OF HOUSTON WILL AT MOST GET 0.1-0.25 INCHES WITH 0.5-1 INCH AMOUNTS ALONG THE COAST. STILL THINK HIGHEST MOISTURE WILL BE OFF TO THE EAST OVER LOUISIANA SO RAINFALL AMOUNTS OF AN INCH OR MORE WILL BE IN THE GULF EASTWARD THROUGH LOUISIANA. STILL DO NOT WANT TO RULE OUT A QUICK 2-3 INCHES IN SOME STRONGER CONVECTION BUT THINK THESE STORMS WILL BE REALLY LOCALIZED AND NOT THE NORM. IT LOOKS LIKE HIGHER MOISTURE OF 1.6-2 INCH PRECIP WATER VALUES WILL LINGER TUE/WED SO WILL KEEP SOME 20/30 POPS IN THE FORECAST FOR MAINLY AFTERNOON STORMS. MOISTURE DOES DECREASE THUR THROUGH SAT SO HAVE POPS TAPERING OFF FROM 20 PERCENT TO NO RAIN CHANCES. UPPER LEVEL PATTERN ALSO UNDERGOES SOME CHANGES DURING THIS TIME. UPPER LEVEL RIDGE CURRENTLY OVER THE S ROCKIES REMAINS WEAK AND NOT WELL ESTABLISHED FOR THE BEGINNING OF THE WEEK. BY THE END OF THE WEEK THE RIDGE STRENGTHENS OVER THE C ROCKIES WITH ANOTHER AMPLIFIED TROUGH OVER THE MID ATLANTIC BY FRIDAY. RIDGE WILL KEEP LOWER THICKNESS HEIGHTS EAST OF THE AREA SO COULD SEE TEMPS CREEPING UP TO UPPER 90S TO NEAR 100 FOR THE END OF THE WEEK. TEMPS AT 850MB WHEN MIXED DOWN AT LEAST SUPPORT TEMPS IN THE UPPER 90S ACROSS THE AREA. 39 MARINE... SCATTERED SHOWERS ARE MOVING THROUGH THE COASTAL WATERS THIS MORNING ALONG THE LEADING EDGE OF DEEPER TROPICAL MOISTURE THAT WILL CONTINUE TO PUSH INTO SOUTHEAST TEXAS TODAY. EXPECT SCATTERED SHOWERS WITH PERHAPS AN ISOLATED THUNDERSTORM THROUGH MONDAY ACROSS THE COASTAL WATERS. LIGHT TO MODERATE SOUTHEASTERLY WINDS WILL CONTINUE THROUGH THE NEXT SEVERAL DAYS. WITH THE EASTERLY COMPONENT TO THE WINDS WE WILL CONTINUE TO SEE TIDE LEVELS AROUND 1 TO 1.5 FEET ABOVE NORMAL VALUES. RIP CURRENTS WILL ALSO REMAIN PROBLEMATIC FOR AREA BEACHES THROUGH THE WEEKEND. 38 && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 96 76 95 76 98 / 30 20 30 20 10 HOUSTON (IAH) 92 77 94 77 96 / 60 30 50 20 20 GALVESTON (GLS) 89 82 90 82 92 / 50 50 50 20 30 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...SMALL CRAFT SHOULD EXERCISE CAUTION UNTIL 4 PM CDT THIS AFTERNOON FOR THE FOLLOWING ZONES: GALVESTON BAY... MATAGORDA BAY...WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL 20 NM TO 60 NM...WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM...WATERS FROM HIGH ISLAND TO FREEPORT OUT 20 NM. && $$ DISCUSSION...31
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
641 AM CDT SUN JUL 7 2013 .UPDATE... SEE AVIATION FOR 12Z TAF DISCUSSION. && .AVIATION... A TROPICAL AIR MASS AND A MOSTLY ELEVATED LOW PRESSURE TROUGH MOVING INTO THE TX COAST WILL DISRUPT THE OCCASIONAL MVFR CIG THIS MORNING. WITH LIGHT WINDS AND BUOYANT AIR IN THE AREA...SCT LOW BASED CUMULUS OF AROUND 1500 FT WILL HAVE TOPS LIFTING TO 10000 FT OR HIGHER AS LIGHT SHOWERS BEGIN TO MOVE TOWARD THE I-35 TERMINALS. WILL LEAVE OUT MENTION OF MVFR CIGS UNTIL THE BETTER CHANCE OF RAINS ARRIVE IN THE EARLY AFTERNOON HOURS AS DEPICTED BY THE HRRR SIMULATED REFLECTIVITY. ANY FEEBLE ATTEMPT TO DEVELOP A SURFACE CIRCULATION EAST OF BRO SHOULD BE HELD IN CHECK AS THE UPPER SUPPORT PUSHES ONSHORE BY TONIGHT. THUS WILL PLAN ON A MORE STEADY ONSHORE WIND BY TONIGHT...AND A MORE ROUTINE FORMATION OF LOW CLOUDS AT AROUND 09Z. HIGH PWAT VALUES COULD SUPPORT ADDITIONAL SHOWERS AROUND DAYBREAK...BUT WILL LEAVE OUT OF THE LATE PERIODS OF THE TAFS UNTIL A BETTER TREND CAN BE ESTABLISHED. && .PREV DISCUSSION... /ISSUED 322 AM CDT SUN JUL 7 2013/ SHORT TERM (TODAY THROUGH MONDAY)... A WEAKENED UPPER LEVEL INVERTED TROUGH FEATURE OVER THE WESTERN GULF OF MEXICO WILL MIGRATE WEST ONTO THE TEXAS COASTAL PLAINS REGION TODAY WITH AN ENHANCEMENT OF SEA BREEZE ACTIVITY LIKELY OVER SOUTHERN AND EASTERN PORTIONS OF THE CWA. HIGH TEMPERATURES TODAY WILL LOWER SLIGHTLY WITH THE INCREASING SURFACE BASED MOISTURE. HIGHS TODAY WILL RANGE FROM THE LOW 90S ACROSS PORTIONS OF THE HILL COUNTRY TO THE MID TO UPPER 90S ELSEWHERE. INCREASING CLOUDINESS TONIGHT WITH A SLIGHT CHANCE OF MOSTLY EARLY EVENING SHOWERS AND STORMS SOUTH AND EAST. LOWS IN THE 70S. THE UPPER TROUGH WILL MOVE ACROSS THE AREA MONDAY WITH DEEP...MOIST TROPICAL EASTERLIES BRINGING A CHANCE OF SHOWERS AND THUNDERSTORMS THROUGHOUT MUCH OF THE AREA. HIGHS MONDAY WILL MODERATE BACK INTO THE LOWER 90S MOST LOCATIONS WITH NEAR 90 HILL COUNTRY. LONG TERM (MONDAY NIGHT THROUGH SATURDAY)... SHOWERS AND STORMS WILL DIMINISH MONDAY EVENING AS THE INVERTED UPPER TROUGH PUSHES DEEPER INTO MEXICO. LOWS MONDAY NIGHT AGAIN MOSTLY IN THE 70S WITH NEAR 70 HILLS. UPPER LEVEL RIDGING WILL BUILD BACK OVER THE REGION TUESDAY AND REMAIN STRONG THROUGH SATURDAY AS THE CENTER OF THE HIGH SHIFTS EAST INTO THE SOUTHERN PLAINS BY LATE IN THE WEEK. CONTINUED DEEP EASTERLIES HOWEVER IN THE MID AND LOWER LEVELS OF THE ATMOSPHERE WILL ENHANCE SOME SEA BREEZE CONVECTION INTO EASTERN SECTIONS BOTH TUESDAY AND WEDNESDAY. MORNING LOW CLOUDS WILL BECOME PARTLY CLOUDY AFTERNOONS BOTH DAYS WITH HIGHS RANGING FROM THE LOW 90S HILLS TO THE UPPER 90S TO NEAR 100 EASTERN SECTIONS. LOWS IN THE 70S. ANOTHER EASTERLY WAVE FEATURE PUSHING ACROSS THE COASTAL PLAINS THURSDAY WILL GENERATE MORE ACTIVITY OVER EASTERN SECTIONS BOTH THURSDAY AND FRIDAY. HIGHS WILL CONTINUE NEAR OR SLIGHTLY ABOVE SEASONAL NORMS THURSDAY THROUGH SATURDAY. LOWS GENERALLY IN THE 70S EXCEPT UPPER 60S TO NEAR 70 HILLS. && .PRELIMINARY POINT TEMPS/POPS... AUSTIN CAMP MABRY 97 75 94 74 100 / 10 20 20 10 - AUSTIN BERGSTROM INTL AIRPORT 97 74 93 72 99 / 10 20 30 10 - NEW BRAUNFELS MUNI AIRPORT 95 73 93 72 96 / 10 20 30 10 10 BURNET MUNI AIRPORT 95 74 91 73 96 / - 10 20 10 - DEL RIO INTL AIRPORT 96 76 92 75 94 / - - 30 20 10 GEORGETOWN MUNI AIRPORT 95 74 93 72 98 / 10 10 20 10 - HONDO MUNI AIRPORT 95 74 90 73 96 / - 10 30 20 - SAN MARCOS MUNI AIRPORT 96 74 93 73 97 / 10 20 30 10 10 LA GRANGE - FAYETTE REGIONAL 95 76 92 75 99 / 40 20 30 10 20 SAN ANTONIO INTL AIRPORT 95 76 91 75 96 / 10 20 30 10 - STINSON MUNI AIRPORT 95 74 92 73 94 / 10 20 30 10 - && .EWX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ MESOSCALE/AVIATION...02 SYNOPTIC/GRIDS...18
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
628 AM CDT SUN JUL 7 2013 .AVIATION... WIDELY SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WERE DRIFTING ACROSS THE SOUTH PLAINS EARLY THIS MORNING. ODDS OF A DIRECT IMPACT AT KLBB ARE LOW BUT NOT ZERO AND GIVEN THAT A SMALL STORM RECENTLY DEVELOPED ABOUT 12 MILES WEST OF THE TERMINAL HAVE DECIDED TO INSERT A VCTS MENTION AT KLBB IN THE SHORT TERM. OUTSIDE OF ANY STORMS...EXPECT VFR CONDITIONS TO PREVAIL WITH SOUTHERLY WINDS...THOUGH AT WEAKER LEVELS THAN THE PAST TWO AFTERNOONS. AFTERNOON CONVECTION SHOULD REMAIN WELL WEST OF THE TERMINALS IN NEW MEXICO. && .PREV DISCUSSION... /ISSUED 343 AM CDT SUN JUL 7 2013/ SHORT TERM... DIRTY SOUTHWESTERN RIDGE HAS EXPANDED TO ENCOMPASS WEST TEXAS AND THIS WILL PROVIDE ANOTHER TOASTY JULY DAY WITH HIGHS SIMILAR TO SATURDAY. MID-LEVEL MOISTURE SPILLING OVER THE SOUTH PLAINS COUPLED WITH WEAK ELEVATED INSTABILITY...DEEP LAYER MOISTURE CONVERGENCE AND ELEVATED FRONTOGENESIS WERE SUPPORTING A FEW RECENTLY DEVELOPED SHOWERS AND STORMS ACROSS THE FAR NORTHWESTERN ZONES. THIS ACTIVITY WAS NOT MOVING MUCH THANKS TO WEAK STEERING FLOW/WINDS WITHIN THE RIDGE...BUT WE COULD SEE AT LEAST ISOLATED ACTIVITY HANG ON ACROSS THE WESTERN ZONES AND PERHAPS EXPAND/DEVELOP TOWARD THE I-27/US-87 CORRIDOR AS THE RECENT RAP AND HRRR RUNS SUGGEST. HENCE HAVE INSERTED A SLIGHT CHANCE OF THUNDERSTORMS INTO THE GRIDS ACROSS THE WESTERN AND INTO THE CENTRAL ZONES IN THE 12-18Z TIME-FRAME. ANY ACTIVITY WILL LIKELY WANE TOWARD MID TO LATE MORNING. STRONG HEATING AND SUFFICIENT MOISTURE WILL THEN YIELD ANOTHER ROUND OF CONVECTION OVER THE HIGHER TERRAIN OF NM AND CO THIS AFTERNOON...BUT SIMILAR TO SATURDAY...THIS ACTIVITY WILL NOT HAVE MUCH INCENTIVE TO MOVE VERY FAR EASTWARD AND SHOULD STAY WELL WEST OF THE CWA. THE MID-LEVEL MOISTURE PLUME WILL STILL EXTEND IN CLOSE PROXIMITY TO THE FAR NORTHWESTERN ZONES LATE TONIGHT AND THERE MAY BE SOME RISK OF LATE NIGHT ELEVATED CONVECTIVE DEVELOPMENT LIKE WE HAVE SEEN THE LAST COUPLE OF NIGHTS. HOWEVER THE MID-LEVEL MOISTURE PLUME IS PROGGED TO THIN/DRY A BIT LOCALLY AND LOW-LEVEL FORCING APPEARS LESS...SO HAVE KEPT THE FORECAST DRY FOR TONIGHT. OTHERWISE...IT WILL BE ANOTHER MILD NIGHT WITH LOWS VARYING FROM THE MID-60S NORTHWEST TO LOWER AND MIDDLE 70S EAST. LONG TERM... AN UPPER LEVEL RIDGE...CENTERED ROUGHLY OVER THE 4-CORNERS INITIALLY... AND GRADUALLY MIGRATING INTO THE CENTRAL HIGH PLAINS...WILL KEEP THE FA HOT AND DRY FOR THE MOST PART THIS UPCOMING WEEK. OROGRAPHICALLY FORCED CONVECTION WITHIN MOISTURE PLUME TRAPPED IN THE RIDGE SHOULD REMAIN TO OUR WEST MONDAY WHILE AN INVERTED TROUGH MOVING WEST ACROSS THE BIG BEND WILL BE OF LITTLE CONSEQUENCE TO OUR WX. WE ARE STILL WATCHING FOR A TEMPORARY WEAKNESS TO DEVELOP IN THE EASTERN PART OF THE RIDGE WED/THU AS A SHORTWAVE MOVES FROM THE CANADIAN PRAIRIES TO THE GREAT LAKES AND A COLD FRONT DIPS INTO SRN CO/SW KS. BUT ANY TSTM ACTIVITY ASSOCIATED WITH THIS WAVE/FRONT APPEARS UNLIKELY TO MAKE IT INTO OUR NRN ZONES LATE WED/EARLY THU. THEN...AS THE UPPER RIDGE RE- EXPANDS E-NEWD WE EXPECT TEMPS TO NUDGE UPWARD A FEW DEGREES HEADING INTO NEXT WEEKEND. EARLY NEXT WEEK...THE UPPER RIDGE MAY START TO RETROGRADE BACK TO THE WEST AS AN UPPER TROUGH/LOW DEVELOPS IN THE DEEP SOUTH. WE ARE COUNTING ON THIS PATTERN CHANGE TO BRING A COOLING TREND AND PERHAPS A CHANCE OF RAIN NEXT WEEK. && .PRELIMINARY POINT TEMPS/POPS... FRIONA 92 66 93 66 95 / 20 10 10 10 10 TULIA 94 67 95 68 96 / 20 10 10 10 10 PLAINVIEW 93 67 95 69 95 / 20 10 10 10 10 LEVELLAND 94 68 94 70 94 / 20 10 10 10 10 LUBBOCK 95 70 95 70 95 / 20 10 10 10 10 DENVER CITY 94 68 93 69 93 / 20 10 10 10 10 BROWNFIELD 95 69 94 70 95 / 20 10 10 10 0 CHILDRESS 99 71 98 74 99 / 0 0 0 0 0 SPUR 97 71 96 72 97 / 0 0 0 0 0 ASPERMONT 98 72 97 74 99 / 0 0 0 0 0 && .LUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 23/33/23
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
624 AM CDT SUN JUL 7 2013 .DISCUSSION... SEE AVIATION FOR 12Z TAF DISCUSSION && .AVIATION... SCATTERED SHOWERS ARE ONGOING ACROSS THE COASTAL COUNTIES THIS MORNING AS THE LEADING EDGE OF DEEP TROPICAL MOISTURE MOVES INLAND. GREATEST CONCERN WITH THIS ISSUANCE REMAINS TIMING AND COVERAGE OF PRECIPITATION TODAY. EXPECT SCATTERED SHOWERS WITH A FEW ISOLATED THUNDERSTORMS MIXED IN ACROSS THE SOUTHERN HALF OF THE REGION. WILL CARRY PROB30 MENTION FOR METRO AREA TAF SITES FOR LATE AFTERNOON AS CONFIDENCE IN TIMING A BIT TOO LOW FOR TEMPO AT THIS TIME. GREATEST IMPACTS WILL BE TO LBX AND GLS WITH DECREASING COVERAGE TO THE NORTH. 38 && .PREV DISCUSSION... /ISSUED 425 AM CDT SUN JUL 7 2013/ DISCUSSION... LATEST RADAR IMAGERY SHOWS A LINE OF SHOWERS JUST REACHING THE UPPER TX COAST THIS MORNING. THIS LINE OF SHOWERS APPEARS TO BE ON THE LEADING EDGE OF HIGHER MOISTURE DELINEATED BY 2 INCH PRECIP WATER VALUES NOTED ON GOES SOUNDER IMAGERY. UPPER LEVEL ANALYSIS AND WATER VAPOR IMAGERY STILL SHOW A DEFORMING SHEAR AXIS WHICH SEEMS TO BE IN THE PROCESS OF WEAKENING. PRESSURE GRADIENT AT THE SFC HAS INCREASED SO GETTING SOME DECENT LOW LEVEL FLOW OFF THE GULF WHICH SHOULD CONTINUE TO ADVECT HIGHER MOISTURE INLAND TODAY. FOR THE MOST PART...GFS/ECMWF MODELS CONTINUE TO SHOW HIGHER MOISTURE MOVE INTO SE TX THIS MORNING AND THROUGH THE EARLY AFTERNOON. THE LATEST HRRR RUNS SEEMS TO SUPPORT THIS WITH CONVECTION DEVELOPING INLAND MAINLY AROUND 15-16Z AND CONTINUING THROUGH 22-23Z THIS AFTERNOON. ACTIVITY LOOKS MORE SCT IN NATURE SO BACKED OFF ON POPS A TOUCH. STILL HAVE 60 POPS FOR THE I-10 CORRIDOR INCLUDING MOST OF HOUSTON. HEAVY RAINFALL THREAT WILL LARGELY DEPEND ON INDIVIDUAL CELLS THAT BECOME STRONG AND FULLY TAP DEEPER MOISTURE. GFS SHOWS PRECIP WATER VALUES GETTING TO AROUND 2-2.2 INCHES WHICH WILL SUPPORT MODERATE TO HEAVY RAINFALL. AGAIN MAIN FLOOD THREAT WILL BE URBAN IN NATURE WITH STORMS THAT CAN QUICKLY PRODUCE 2 INCHES IN AN HOUR. OTHERWISE DRY GROUNDS SHOULD BE ABLE TO ABSORB A LOT OF THE RUN OFF AND NOT CONTRIBUTE TO FLOODING. WITH MOISTURE SLOWLY PUSHING INTO THE AREA...ALSO INCREASED MAX TEMPS A COUPLE OF DEGREES AS CLOUD COVER WILL BE SLOW TO FILL IN ACROSS THE AREA. LOOK FOR 1.8-2 INCH PW VALUES TO REMAIN OVER SE TX THROUGH MONDAY SO WENT WITH 40/50 POPS FOR SCATTERED ACTIVITY DURING THE DAY. AGAIN MOST OF THIS ACTIVITY WILL BE DIURNALLY DRIVEN SO WILL HAVE LOWER POPS OVERNIGHT. RAINFALL AMOUNTS AGAIN EXPECTED TO BE CONFINED TO THE COAST. HOUSTON AREA MAY GET WIDE SPREAD HALF INCH AMOUNTS BUT THAT WILL BE PUSHING IT. NORTH OF HOUSTON EXPECT RAINFALL AMOUNTS TO REALLY DROP OFF AND AREAS FROM CONROE TO COLLEGE STATION MAY NOT SEE ANY RAINFALL. BY AND LARGE THINK AREAS NORTH OF HOUSTON WILL AT MOST GET 0.1-0.25 INCHES WITH 0.5-1 INCH AMOUNTS ALONG THE COAST. STILL THINK HIGHEST MOISTURE WILL BE OFF TO THE EAST OVER LOUISIANA SO RAINFALL AMOUNTS OF AN INCH OR MORE WILL BE IN THE GULF EASTWARD THROUGH LOUISIANA. STILL DO NOT WANT TO RULE OUT A QUICK 2-3 INCHES IN SOME STRONGER CONVECTION BUT THINK THESE STORMS WILL BE REALLY LOCALIZED AND NOT THE NORM. IT LOOKS LIKE HIGHER MOISTURE OF 1.6-2 INCH PRECIP WATER VALUES WILL LINGER TUE/WED SO WILL KEEP SOME 20/30 POPS IN THE FORECAST FOR MAINLY AFTERNOON STORMS. MOISTURE DOES DECREASE THUR THROUGH SAT SO HAVE POPS TAPERING OFF FROM 20 PERCENT TO NO RAIN CHANCES. UPPER LEVEL PATTERN ALSO UNDERGOES SOME CHANGES DURING THIS TIME. UPPER LEVEL RIDGE CURRENTLY OVER THE S ROCKIES REMAINS WEAK AND NOT WELL ESTABLISHED FOR THE BEGINNING OF THE WEEK. BY THE END OF THE WEEK THE RIDGE STRENGTHENS OVER THE C ROCKIES WITH ANOTHER AMPLIFIED TROUGH OVER THE MID ATLANTIC BY FRIDAY. RIDGE WILL KEEP LOWER THICKNESS HEIGHTS EAST OF THE AREA SO COULD SEE TEMPS CREEPING UP TO UPPER 90S TO NEAR 100 FOR THE END OF THE WEEK. TEMPS AT 850MB WHEN MIXED DOWN AT LEAST SUPPORT TEMPS IN THE UPPER 90S ACROSS THE AREA. 39 MARINE... SCATTERED SHOWERS ARE MOVING THROUGH THE COASTAL WATERS THIS MORNING ALONG THE LEADING EDGE OF DEEPER TROPICAL MOISTURE THAT WILL CONTINUE TO PUSH INTO SOUTHEAST TEXAS TODAY. EXPECT SCATTERED SHOWERS WITH PERHAPS AN ISOLATED THUNDERSTORM THROUGH MONDAY ACROSS THE COASTAL WATERS. LIGHT TO MODERATE SOUTHEASTERLY WINDS WILL CONTINUE THROUGH THE NEXT SEVERAL DAYS. WITH THE EASTERLY COMPONENT TO THE WINDS WE WILL CONTINUE TO SEE TIDE LEVELS AROUND 1 TO 1.5 FEET ABOVE NORMAL VALUES. RIP CURRENTS WILL ALSO REMAIN PROBLEMATIC FOR AREA BEACHES THROUGH THE WEEKEND. 38 && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 96 75 95 75 97 / 30 20 30 20 10 HOUSTON (IAH) 93 76 94 76 96 / 60 30 50 20 20 GALVESTON (GLS) 88 80 90 81 90 / 50 50 50 20 30 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ DISCUSSION...39 AVIATION/MARINE...38
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
425 AM CDT SUN JUL 7 2013 .DISCUSSION... LATEST RADAR IMAGERY SHOWS A LINE OF SHOWERS JUST REACHING THE UPPER TX COAST THIS MORNING. THIS LINE OF SHOWERS APPEARS TO BE ON THE LEADING EDGE OF HIGHER MOISTURE DELINEATED BY 2 INCH PRECIP WATER VALUES NOTED ON GOES SOUNDER IMAGERY. UPPER LEVEL ANALYSIS AND WATER VAPOR IMAGERY STILL SHOW A DEFORMING SHEAR AXIS WHICH SEEMS TO BE IN THE PROCESS OF WEAKENING. PRESSURE GRADIENT AT THE SFC HAS INCREASED SO GETTING SOME DECENT LOW LEVEL FLOW OFF THE GULF WHICH SHOULD CONTINUE TO ADVECT HIGHER MOISTURE INLAND TODAY. FOR THE MOST PART...GFS/ECMWF MODELS CONTINUE TO SHOW HIGHER MOISTURE MOVE INTO SE TX THIS MORNING AND THROUGH THE EARLY AFTERNOON. THE LATEST HRRR RUNS SEEMS TO SUPPORT THIS WITH CONVECTION DEVELOPING INLAND MAINLY AROUND 15-16Z AND CONTINUING THROUGH 22-23Z THIS AFTERNOON. ACTIVITY LOOKS MORE SCT IN NATURE SO BACKED OFF ON POPS A TOUCH. STILL HAVE 60 POPS FOR THE I-10 CORRIDOR INCLUDING MOST OF HOUSTON. HEAVY RAINFALL THREAT WILL LARGELY DEPEND ON INDIVIDUAL CELLS THAT BECOME STRONG AND FULLY TAP DEEPER MOISTURE. GFS SHOWS PRECIP WATER VALUES GETTING TO AROUND 2-2.2 INCHES WHICH WILL SUPPORT MODERATE TO HEAVY RAINFALL. AGAIN MAIN FLOOD THREAT WILL BE URBAN IN NATURE WITH STORMS THAT CAN QUICKLY PRODUCE 2 INCHES IN AN HOUR. OTHERWISE DRY GROUNDS SHOULD BE ABLE TO ABSORB A LOT OF THE RUN OFF AND NOT CONTRIBUTE TO FLOODING. WITH MOISTURE SLOWLY PUSHING INTO THE AREA...ALSO INCREASED MAX TEMPS A COUPLE OF DEGREES AS CLOUD COVER WILL BE SLOW TO FILL IN ACROSS THE AREA. LOOK FOR 1.8-2 INCH PW VALUES TO REMAIN OVER SE TX THROUGH MONDAY SO WENT WITH 40/50 POPS FOR SCATTERED ACTIVITY DURING THE DAY. AGAIN MOST OF THIS ACTIVITY WILL BE DIURNALLY DRIVEN SO WILL HAVE LOWER POPS OVERNIGHT. RAINFALL AMOUNTS AGAIN EXPECTED TO BE CONFINED TO THE COAST. HOUSTON AREA MAY GET WIDE SPREAD HALF INCH AMOUNTS BUT THAT WILL BE PUSHING IT. NORTH OF HOUSTON EXPECT RAINFALL AMOUNTS TO REALLY DROP OFF AND AREAS FROM CONROE TO COLLEGE STATION MAY NOT SEE ANY RAINFALL. BY AND LARGE THINK AREAS NORTH OF HOUSTON WILL AT MOST GET 0.1-0.25 INCHES WITH 0.5-1 INCH AMOUNTS ALONG THE COAST. STILL THINK HIGHEST MOISTURE WILL BE OFF TO THE EAST OVER LOUISIANA SO RAINFALL AMOUNTS OF AN INCH OR MORE WILL BE IN THE GULF EASTWARD THROUGH LOUISIANA. STILL DO NOT WANT TO RULE OUT A QUICK 2-3 INCHES IN SOME STRONGER CONVECTION BUT THINK THESE STORMS WILL BE REALLY LOCALIZED AND NOT THE NORM. IT LOOKS LIKE HIGHER MOISTURE OF 1.6-2 INCH PRECIP WATER VALUES WILL LINGER TUE/WED SO WILL KEEP SOME 20/30 POPS IN THE FORECAST FOR MAINLY AFTERNOON STORMS. MOISTURE DOES DECREASE THUR THROUGH SAT SO HAVE POPS TAPERING OFF FROM 20 PERCENT TO NO RAIN CHANCES. UPPER LEVEL PATTERN ALSO UNDERGOES SOME CHANGES DURING THIS TIME. UPPER LEVEL RIDGE CURRENTLY OVER THE S ROCKIES REMAINS WEAK AND NOT WELL ESTABLISHED FOR THE BEGINNING OF THE WEEK. BY THE END OF THE WEEK THE RIDGE STRENGTHENS OVER THE C ROCKIES WITH ANOTHER AMPLIFIED TROUGH OVER THE MID ATLANTIC BY FRIDAY. RIDGE WILL KEEP LOWER THICKNESS HEIGHTS EAST OF THE AREA SO COULD SEE TEMPS CREEPING UP TO UPPER 90S TO NEAR 100 FOR THE END OF THE WEEK. TEMPS AT 850MB WHEN MIXED DOWN AT LEAST SUPPORT TEMPS IN THE UPPER 90S ACROSS THE AREA. 39 && .MARINE... SCATTERED SHOWERS ARE MOVING THROUGH THE COASTAL WATERS THIS MORNING ALONG THE LEADING EDGE OF DEEPER TROPICAL MOISTURE THAT WILL CONTINUE TO PUSH INTO SOUTHEAST TEXAS TODAY. EXPECT SCATTERED SHOWERS WITH PERHAPS AN ISOLATED THUNDERSTORM THROUGH MONDAY ACROSS THE COASTAL WATERS. LIGHT TO MODERATE SOUTHEASTERLY WINDS WILL CONTINUE THROUGH THE NEXT SEVERAL DAYS. WITH THE EASTERLY COMPONENT TO THE WINDS WE WILL CONTINUE TO SEE TIDE LEVELS AROUND 1 TO 1.5 FEET ABOVE NORMAL VALUES. RIP CURRENTS WILL ALSO REMAIN PROBLEMATIC FOR AREA BEACHES THROUGH THE WEEKEND. 38 && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 96 75 95 75 97 / 30 20 30 20 10 HOUSTON (IAH) 93 76 94 76 96 / 60 30 50 20 20 GALVESTON (GLS) 88 80 90 81 90 / 50 50 50 20 30 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ DISCUSSION...39 AVIATION/MARINE...38
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
343 AM CDT SUN JUL 7 2013 .SHORT TERM... DIRTY SOUTHWESTERN RIDGE HAS EXPANDED TO ENCOMPASS WEST TEXAS AND THIS WILL PROVIDE ANOTHER TOASTY JULY DAY WITH HIGHS SIMILAR TO SATURDAY. MID-LEVEL MOISTURE SPILLING OVER THE SOUTH PLAINS COUPLED WITH WEAK ELEVATED INSTABILITY...DEEP LAYER MOISTURE CONVERGENCE AND ELEVATED FRONTOGENESIS WERE SUPPORTING A FEW RECENTLY DEVELOPED SHOWERS AND STORMS ACROSS THE FAR NORTHWESTERN ZONES. THIS ACTIVITY WAS NOT MOVING MUCH THANKS TO WEAK STEERING FLOW/WINDS WITHIN THE RIDGE...BUT WE COULD SEE AT LEAST ISOLATED ACTIVITY HANG ON ACROSS THE WESTERN ZONES AND PERHAPS EXPAND/DEVELOP TOWARD THE I-27/US-87 CORRIDOR AS THE RECENT RAP AND HRRR RUNS SUGGEST. HENCE HAVE INSERTED A SLIGHT CHANCE OF THUNDERSTORMS INTO THE GRIDS ACROSS THE WESTERN AND INTO THE CENTRAL ZONES IN THE 12-18Z TIME-FRAME. ANY ACTIVITY WILL LIKELY WANE TOWARD MID TO LATE MORNING. STRONG HEATING AND SUFFICIENT MOISTURE WILL THEN YIELD ANOTHER ROUND OF CONVECTION OVER THE HIGHER TERRAIN OF NM AND CO THIS AFTERNOON...BUT SIMILAR TO SATURDAY...THIS ACTIVITY WILL NOT HAVE MUCH INCENTIVE TO MOVE VERY FAR EASTWARD AND SHOULD STAY WELL WEST OF THE CWA. THE MID-LEVEL MOISTURE PLUME WILL STILL EXTEND IN CLOSE PROXIMITY TO THE FAR NORTHWESTERN ZONES LATE TONIGHT AND THERE MAY BE SOME RISK OF LATE NIGHT ELEVATED CONVECTIVE DEVELOPMENT LIKE WE HAVE SEEN THE LAST COUPLE OF NIGHTS. HOWEVER THE MID-LEVEL MOISTURE PLUME IS PROGGED TO THIN/DRY A BIT LOCALLY AND LOW-LEVEL FORCING APPEARS LESS...SO HAVE KEPT THE FORECAST DRY FOR TONIGHT. OTHERWISE...IT WILL BE ANOTHER MILD NIGHT WITH LOWS VARYING FROM THE MID-60S NORTHWEST TO LOWER AND MIDDLE 70S EAST. && .LONG TERM... AN UPPER LEVEL RIDGE...CENTERED ROUGHLY OVER THE 4-CORNERS INITIALLY... AND GRADUALLY MIGRATING INTO THE CENTRAL HIGH PLAINS...WILL KEEP THE FA HOT AND DRY FOR THE MOST PART THIS UPCOMING WEEK. OROGRAPHICALLY FORCED CONVECTION WITHIN MOISTURE PLUME TRAPPED IN THE RIDGE SHOULD REMAIN TO OUR WEST MONDAY WHILE AN INVERTED TROUGH MOVING WEST ACROSS THE BIG BEND WILL BE OF LITTLE CONSEQUENCE TO OUR WX. WE ARE STILL WATCHING FOR A TEMPORARY WEAKNESS TO DEVELOP IN THE EASTERN PART OF THE RIDGE WED/THU AS A SHORTWAVE MOVES FROM THE CANADIAN PRAIRIES TO THE GREAT LAKES AND A COLD FRONT DIPS INTO SRN CO/SW KS. BUT ANY TSTM ACTIVITY ASSOCIATED WITH THIS WAVE/FRONT APPEARS UNLIKELY TO MAKE IT INTO OUR NRN ZONES LATE WED/EARLY THU. THEN...AS THE UPPER RIDGE RE- EXPANDS E-NEWD WE EXPECT TEMPS TO NUDGE UPWARD A FEW DEGREES HEADING INTO NEXT WEEKEND. EARLY NEXT WEEK...THE UPPER RIDGE MAY START TO RETROGRADE BACK TO THE WEST AS AN UPPER TROUGH/LOW DEVELOPS IN THE DEEP SOUTH. WE ARE COUNTING ON THIS PATTERN CHANGE TO BRING A COOLING TREND AND PERHAPS A CHANCE OF RAIN NEXT WEEK. && .PRELIMINARY POINT TEMPS/POPS... FRIONA 92 66 93 66 95 / 20 10 10 10 10 TULIA 94 67 95 68 96 / 20 10 10 10 10 PLAINVIEW 93 67 95 69 95 / 20 10 10 10 10 LEVELLAND 94 68 94 70 94 / 20 10 10 10 10 LUBBOCK 95 70 95 70 95 / 20 10 10 10 10 DENVER CITY 94 68 93 69 93 / 20 10 10 10 10 BROWNFIELD 95 69 94 70 95 / 20 10 10 10 0 CHILDRESS 99 71 98 74 99 / 0 0 0 0 0 SPUR 97 71 96 72 97 / 0 0 0 0 0 ASPERMONT 98 72 97 74 99 / 0 0 0 0 0 && .LUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 23/33
AREA FORECAST DISCUSSION
NWS SPOKANE WA
446 PM PDT Mon Jul 8 2013 .SYNOPSIS... A weather system passing through the Inland Northwest today will promote scattered showers and thunderstorms across the northern mountains of Washington and Idaho, as well as southeast Washington. Tuesday and Wednesday will be the warmest days this week with high temperatures in the upper 80s to mid 90s. Thursday through Saturday will be occasionally breezy with temperatures pretty close to average, or slightly below. Low shower and thunderstorms chances will linger near the mountains, especially closer to the Canadian border, but otherwise conditions will be dry. Temperatures begin to warm up again slightly going into early next week. && .DISCUSSION... This Afternoon and Evening: The weather over northeast Washington and the Idaho Panhandle will be active. Scattered thunderstorms are expected through early this evening. Our concern area extends from the Okanogan Highlands through northeast Washington into the northern and central Idaho Panhandle. The 2 PM visible imagery shows a mid-level atmospheric circulation in far southeast British Columbia slowly moving east. Around this circulation the atmosphere has become increasingly unstable with the RUC analysis indicating 500 to 1000 J/KG of surface based CAPE from Republic to Sandpoint to Spokane to Kellogg. Very little convective inhibition remains, so look for convection to continue to develop through late afternoon. Shear and buoyancy values suggest the potential for organized multi-cell thunderstorms. Our main threat through 6 PM will be the potential for hail, heavy rain, and gusty winds. A couple severe thunderstorm warnings may be needed, but most of the cells through early evening will probably pulse up, produce hail up to dime size, then pulse down. The threat for thunderstorms should dissipate quickly early this evening as the upper level support (upper low in SE BC) moves east of the region focusing the threat over Montana. Tuesday: A shortwave ridge of high pressure will replace the trough over the Inland Northwest for Tuesday. Look for relatively light winds, clear skies and temperatures 5 to 8 degrees above average. /GKoch Tuesday night through Thursday evening...General long-wave trof lingers overhead but the air-mass contained in it is not very unstable and does not have much moisture tied to any discrete feature traversing through it. As thus for the most part a dry forecast remains, with exception being minimal chance for afternoon/evening mountain thunderstorms up North and over the Idaho Panhandle Thursday afternoon and evening. Forecast temperatures remain just slightly on the warm side of what would be considered normal for this time of year. Other shortwave features of note will be a dry disturbance passage on Wednesday afternoon and evening which will increase the wind some but only to low breezy category at most. /Pelatti Thursday night through Monday: The Inland Northwest remains in a more active pattern through the week`s end, before high pressure starts to nudge in Sunday and Monday. A shortwave system continues to slip through Idaho into Montana Thursday night, even as a second shortwave begins to move toward the Cascades. That second shortwave slips across eastern Washington and north Idaho through Friday, with a third wave slipping by Saturday before high pressure begins to nudge in Saturday night. Models continue to disagree over some of the details. Yet the progression of these features will bring some shower and thunderstorm chances to the region. The main chances remain around the northern mountains. Smaller chances will be found across the Blue Mountains through the Central Panhandle, including the Palouse as the wave is exiting Thursday night. While some of these waves are depicted as being somewhat dynamic/strong, models still do not depict significant instability and keep the deeper moisture southeast of the region. So regardless of timing and track, fuel for showers is not impressive. Thus over PoPs remain slight or isolated in nature. Look for occasional breezy conditions, especially Friday, with the passage of these waves. Although a couple models skim another wave by southern BC, near the WA/ID border early next week, drier conditions are forecast going into Sunday and Monday. Look for slightly cooler than normal conditions around the end of the work week, before temperatures warm closer to or slightly above seasonal norms going into early next week. /J. Cote` && .AVIATION... 00Z TAFS: Showers and thunderstorms will be the main aviation impact through 02z. The window of opportunity for thunderstorms is decreasing as the upper trough is shifting into western Montana. Hail up to dime size, gusts to 30 mph and very brief heavy rain look to be the upper end of what we can expect with the strongest cells. Aft 02z expect periods of think high clouds moving through otherwise SKC and light winds. && .PRELIMINARY POINT TEMPS/POPS... Spokane 58 89 60 89 59 83 / 0 0 0 0 0 10 Coeur d`Alene 56 87 58 87 58 83 / 10 0 0 0 0 10 Pullman 53 87 55 88 55 82 / 0 0 0 10 10 10 Lewiston 62 95 64 95 63 90 / 0 0 0 10 10 10 Colville 53 90 56 92 56 86 / 10 0 0 0 0 10 Sandpoint 50 85 53 86 54 82 / 20 0 0 0 0 10 Kellogg 54 87 57 87 58 82 / 10 0 0 0 10 10 Moses Lake 60 94 62 94 60 87 / 0 0 0 0 0 0 Wenatchee 64 92 65 91 62 85 / 0 0 0 0 0 0 Omak 60 94 60 92 59 86 / 0 0 0 0 0 10 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...None. WA...None. && $$
AREA FORECAST DISCUSSION
NWS SPOKANE WA
1043 AM PDT Sun Jul 7 2013 .SYNOPSIS... There will be a chance for thunderstorms over the North Cascades this afternoon with the remainder of the region generally warm and dry. The threat for showers and thunderstorms will migrate east overnight into portions of Eastern WA and into the Idaho Panhandle on Monday. Tuesday and Wednesday should be the warmest days of the week with continued dry conditions. Wednesday will be locally breezy...especially in and near the Cascades with the arrival of a cold front late. The front could knock temperatures back close to normal for Thursday, Friday, and Saturday. && .DISCUSSION... Surface-based cumulus are starting to develop over the ridges of the north Cascades. Still too shallow to see anything on radar. 15Z HRRR still shows stronger convection developing in the next few hours, which is in line with the current forecast. As the short wave responsible for this convection tracks eastward across our area, the showers/thunderstorms will move across the northern mountain areas overnight. Could see a stray shower over the Basin north of Highway 2, including the Spokane/CdA metro area. Meanwhile another area of thunderstorms will develop tonight after midnight over southeast WA and the southern Panhandle. This activity will stay south of the I-90 corridor overnight and into Monday morning. RJ && .AVIATION... 18Z TAFS: Thunderstorms are expected to develop over the Cascades this afternoon and may affect the KEAT TAF site around 00Z today. These showers/thunderstorms will track across the northern mountains overnight and into the northern Panhandle. There is a very low probability that they may bring a light shower to the KGEG/KSFF/KCOE TAF sites late tonight, but the probability was too low to include in the TAF. Meanwhile to the south thunderstorms may develop over the Blue Mtns this afternoon/evening but this is a low probability event. A much better chance of thunderstorms will occur later tonight from the Blue Mtns across the southern Idaho Panhandle. These should move east of the area by mid-morning Monday. RJ && .PRELIMINARY POINT TEMPS/POPS... Spokane 85 58 84 58 88 60 / 0 10 20 0 0 0 Coeur d`Alene 84 56 82 54 86 58 / 0 10 20 10 0 0 Pullman 83 53 82 50 88 55 / 0 10 10 0 0 0 Lewiston 92 62 90 60 95 64 / 0 20 10 0 0 0 Colville 88 53 86 52 91 56 / 10 30 50 10 0 0 Sandpoint 83 51 79 49 85 53 / 0 10 50 20 0 0 Kellogg 83 55 80 54 87 57 / 0 10 20 10 0 0 Moses Lake 91 60 90 59 94 62 / 0 10 0 0 0 0 Wenatchee 89 62 89 63 92 65 / 10 20 0 0 0 0 Omak 89 58 89 58 93 60 / 10 20 10 0 0 0 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...None. WA...None. && $$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
942 PM CDT MON JUL 8 2013 .UPDATE... ISSUED AT 942 PM CDT MON JUL 8 2013 TRYING TO FIGURE OUT THE CONVECTIVE EVOLUTION FORECAST FROM THE OVERNIGHT HOURS THROUGH TUESDAY REMAINS VERY PROBLEMATIC. FIRST...A LINE OF SHOWERS AND THUNDERSTORMS SET UP JUST NORTH OF US-20 AND NEAR THE CLAYTON/GRANT COUNTY LINE. THESE STORMS WERE ALONG A QUASI-STATIONARY FRONTAL BOUNDARY AND AIDED BY MLCAPES OF 2000-2500 J/KG PER RAP ANALYSIS. THEY HAVE BEEN VERY EFFICIENT RAIN PRODUCERS WITH RAINFALL RATES OF 1 TO 2 INCHES PER HOUR BEING OBSERVED IN EDGEWOOD AND GREELEY IA. LACK OF ANY 0-6KM SHEAR HAS RESULTED IN THE STORMS COLLAPSING. ADDITIONALLY...LOSS OF DAYTIME HEATING ALLOWING THE CAPE TO DIMINISH...THOUGH DEWPOINTS UP IN THE MID 70S POOLED ALONG THE BOUNDARY RESULTING IN A SLOW DIMINISHMENT. ANTICIPATING THESE STORMS MAY END UP FALLING PART IN THE NEXT HOUR. NOW FOR THE OVERNIGHT INTO TUESDAY. CONVECTION ACROSS SOUTH DAKOTA AND NEBRASKA HAS BEEN MUCH LESS THAN WHAT MANY MODELS UP TO THIS POINT HAD SUGGESTED...INCLUDING HIGH RESOLUTION MODELS. THUS...THE IDEA OF AN MCS ROLLING OUT OF THIS REGION AND IMPACTING THE FORECAST AREA LATE TONIGHT IS VERY MUCH IN QUESTION. LOOKING AT OBSERVATIONAL DATA...THERE IS A SHORTWAVE OVER SOUTHWEST SOUTH DAKOTA INTO FAR WESTERN NEBRASKA WITH ISOLATED CONVECTION ACCOMPANYING IT. AHEAD OF THE SHORTWAVE...850MB WINDS HAVE BEEN INCREASING OVER KANSAS AND NEBRASKA PER RADAR/PROFILER DATA...WITH HINTS OF A WARM FRONTAL ZONE ACROSS SOUTHERN NEBRASKA. THIS IS SHOWN TOO IN LATEST SURFACE ANALYSIS. ONCE THESE FEATURES MEET UP...LIKELY IN CENTRAL/EASTERN NEBRASKA...WOULD IMAGINE CONVECTION WILL INCREASE THERE. THE CONVECTION WILL LIKELY HEAD EAST THROUGH THE MEAN FLOW TOWARDS SOUTHERN SECTIONS OF THE FORECAST AREA...UNLESS IT UPSCALES INTO AN MCS...WHICH THEN MAY HEAD SOUTHEAST AWAY FROM THE AREA PER BOTH NORMAL CORFIDI VECTORS AND PROPAGATING CORFIDI VECTORS. HEADING INTO TUESDAY...THERE ARE INDICATIONS FROM THE 09.00Z NAM/RAP...08.12Z ECMWF/REGIONAL CANADIAN AND 08.18Z GFS OF 850MB MOISTURE TRANSPORT PICKING UP ACROSS CENTRAL IOWA...WITH THE NOSE OF IT POINTED RIGHT INTO THE FORECAST AREA AT 18Z. THIS COULD CONCEIVABLY INITIATE PLENTY OF CONVECTION FROM LATE MORNING THROUGH A BULK OF THE AFTERNOON HOURS. THESE WOULD BE EFFICIENT RAIN PRODUCERS GIVEN DEEP WARM CLOUD DEPTHS AND PRECIPITABLE WATER VALUES UPWARDS OF 2 INCHES. IF THIS CONVECTION FORMS...BY THE TIME THE COLD FRONT COMING THROUGH MINNESOTA APPROACHES THE FORECAST AREA IN THE EVENING...WE MAY NOT HAVE ENOUGH INSTABILITY TO DO MUCH WITH IT. WE WILL JUST HAVE TO SEE HOW OVERNIGHT CONVECTION PLAYS OUT...SINCE AN MCV GOING SOUTH OF US COULD PRODUCE ENOUGH SUBSIDENCE TO PRECLUDE MUCH CONVECTION IN ITS WAKE FOR TUESDAY. THE PRESENCE OF THE MCV WOULD LIKE DISTORT THE PROGGED 850MB MOISTURE TRANSPORT ZONE TOO. TUESDAY THEN WOULD BE A VERY WARM DAY AGAIN WITH HIGHS ABOVE CURRENT FORECAST...WITH SEVERE WEATHER POTENTIAL IN THE EVENING AS THE COLD FRONT MOVES IN. && .SHORT TERM...(TONIGHT THROUGH TUESDAY) ISSUED AT 250 PM CDT MON JUL 8 2013 WARM FRONT SLATED TO WAVER WEST-EAST ACROSS SOUTHERN IA TONIGHT/TUE. THE LOW LEVEL JET/MOISTURE TRANSPORT FOCUSES INTO THE BOUNDARY ACROSS CENTRAL IA TONIGHT...AND SHOWER/STORMS SHOULD DEVELOP AS A RESULT. THE LOW LEVEL FORCING PUSHES NORTHEAST ACROSS THE FORECAST AREA TUE MORNING WHILE A PIECE OF UPPER LEVEL ENERGY TRACKS FROM THE NORTHERN PLAINS TO ACROSS THE UPPER MISSISSIPPI RIVER VALLEY BETWEEN 12-18Z. WOULD EXPECT TO SEE A SHIFT NORTHWARD WITH THE MORE FAVORABLE CONVECTIVE REGION AS A RESULT...MOSTLY ALONG AND NORTH OF I-90. A STRONGER UPPER LEVEL SHORTWAVE TROUGH PROGGED TO SLIP ACROSS THE NORTHERN PLAINS AND INTO NORTHERN MN BY 00Z WED. A COLD FRONT WILL SURGE AHEAD OF THIS SHORTWAVE...GETTING TO THE MISSISSIPPI RIVER BY 00Z. THE GFS AND NAM BUILD 4000+ J/KG OF MUCAPE AHEAD OF THE FRONT...WITH 40+ KTS OF 0-6 KM SHEAR. INSTABILITY WILL DEPEND ON HOW LONG THE MORNING SHOWERS/STORMS LINGER ACROSS THE LOCAL AREA...AND HOW QUICKLY THE DEBRIS CLOUDS CLEAR. AS IT STANDS...IF PARAMETERS MANIFEST PER MODELED FORECAST...IT WOULD BE A GOOD SETUP FOR SEVERE WEATHER. HOWEVER...IF PCPN LINGERS LINGERS...INSTABILITY WILL BE MUCH LOWER...LESSENING THE SEVERE THREAT. A VERY CONDITIONAL SEVERE WEATHER THREAT THAT WON/T BECOME CLEARER UNTIL THE AFTERNOON HOURS. HERE IS HOW TUE COULD PLAY OUT...MORNING CONVECTION ASSOCIATED WITH THE LOW LEVEL JET ADVANCES NORTHEAST ACROSS THE REGION. COULD BE SOME LINGERING SHOWERS/STORMS IN THE AFTERNOON...BUT ENVISION A BREAK FROM THE WIDESPREAD PCPN CHANCES. SHOWERS/STORMS SPARK ALONG AND AHEAD OF THE COLD FRONT BY LATE AFTERNOON/EVENING. MAYBE A BETTER CHANCE NORTH OF I-94. ALSO...BELIEVE THE HIGHER SEVERE RISK WILL BE DURING THIS TIME. .LONG TERM...(WEDNESDAY THROUGH SUNDAY) ISSUED AT 250 PM CDT MON JUL 8 2013 HIGH PRESSURE BUILDS ACROSS THE UPPER MISSISSIPPI RIVER VALLEY FROM THE WEST ON WEDNESDAY...AND LOOKS TO BE THE MAIN WEATHER INFLUENCE THROUGH THE BETTER PART OF FRIDAY. THE HEAT/HUMIDITY OF THE PAST FEW DAYS WILL SWEEP EAST DURING THIS PERIOD...WITH COMPARATIVELY COOLER AND LESS MUGGY CONDITIONS RESULTING. AN UPPER LEVEL SHORTWAVE TROUGH IS THEN SLATED TO DRIVE FROM THE PAC NW TO ACROSS SOUTHERN CANADA FOR THE UPCOMING WEEKEND. WHILE CURRENT TRENDS FAVOR KEEPING MOST OF THE UPPER LEVEL ENERGY NORTH OF THE FORECAST AREA...THE GFS AND ECMWF WOULD SLIDE AN ASSOCIATED COLD FRONT ACROSS THE REGION. WITH THE WINDS FLIPPING TO THE SOUTH AS THE HIGH EEKS TO THE EAST...LOW LEVEL MOISTURE WOULD INCREASE AHEAD OF THE SFC BOUNDARY...AS WOULD INSTABILITY. EXPECT SOME CONVECTION AROUND THE FRONT AS RESULT. DETAILS ON WHEN/WHERE ISN/T CLEAR AT THIS TIME...WITH SOME MODEL DIFFERENCES ON TIMING AND PLACEMENT OF THE RELEVANT FEATURES. THE SFC FRONT COULD THEN GET HUNG UP FROM WEST TO EAST ACROSS THE REGION...SERVING AS A POSSIBLE SHOWER/STORM FOCUS THROUGH THE WEEKEND. WILL LEAN ON THE CONSENSUS/EC SOLUTION FOR PCPN CHANCES FOR NOW. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING) ISSUED AT 618 PM CDT MON JUL 8 2013 DAYTIME MIXING HAS HELPED TO CLEAR OUT THE CLOUDS THAT WERE PRESENT DURING THE DAY TODAY AROUND THE TAF SITES. MUCH OF THE EVENING APPEARS IT SHOULD BE CLEAR...AND COMBINED WITH LIGHT WINDS AND THE HIGH 70 DEGREE F DEWPOINTS IN PLACE WILL LIKELY LEAD TO SOME MVFR BR DEVELOPING AROUND MIDNIGHT. LATE IN THE NIGHT... NUMEROUS COMPUTER MODELS SUGGEST THUNDERSTORMS DEVELOPING ACROSS SOUTH DAKOTA AND NEBRASKA WILL BEGIN TO APPROACH THE TAF SITES. THE TRACK AND TIMING OF THESE ARE STILL UNCERTAIN...THOUGH...WITH POTENTIAL FOR THEM TO DIVE MORE TO THE SOUTH OF THE TAF SITES. CONSENSUS SEEMS TO SUGGEST THAT THE PRECIPITATION WILL CROSS RST BETWEEN 11-17Z AND LSE BETWEEN 13-18Z. DID NOT CHANGE THE VCTS TO -TSRA YET BECAUSE OF CONCERN ON THE TRACK OF THE STORMS. AS THE THUNDERSTORM EVOLUTION BECOMES CLEARER ACROSS SOUTH DAKOTA AND NEBRASKA...MORE DETAIL WILL BE PROVIDED TO THE TAFS. FOR THE AFTERNOON...A COLD FRONT IS FORECAST TO DROP SOUTHEAST THROUGH MINNESOTA. THIS FRONT WILL LIKELY TRIGGER MORE STORMS BUT THESE MAY NOT MAKE INTO THE TAF SITES UNTIL AFTER 00Z. HOWEVER...WITH A MUGGY AIRMASS IN PLACE AND DAYTIME HEATING IN THE WAKE OF MORNING PRECIPITATION...ADDITIONAL SHOWER ACTIVITY FROM VFR CUMULUS MAY FORM DURING THE AFTERNOON. THUS HAVE A VCSH FROM 18-00Z IN BOTH TAFS. VISIBILITIES ARE LIKELY TO IMPROVE TO VFR FOR THE AFTERNOON TOO AIDED BY DAYTIME HEATING. && .HYDROLOGY...(TUESDAY) ISSUED AT 250 PM CDT MON JUL 8 2013 PWS CLOSE TO 2 INCHES THROUGH TUE...AROUND 170 PERCENT OF NORMAL...WHILE WARM CLOUD DEPTH IS 3500-4000 M. ALL SUPPORT THE POTENTIAL FOR HEAVY RAIN. HOWEVER...THE EXPECTED PCPN LOOKS TRANSITORY...NOT LINGERING NOR MUCH TRAINING....WHILE FFG IS 2.5-3 INCHES IN 3 HOURS. THE MOISTURE TRANSPORT ISN/T OVERLY STRONG NOR DOES IT FOCUS FOR A PROLONGED PERIOD. SO...WHILE THE ATMOSPHERE COULD SUPPORT HEAVY RAIN...OTHER ASPECTS MINIMIZE A FLASH FLOOD THREAT. IF PCPN RATES COULD BECOME HIGH ENOUGH...FLASH FLOODING OR URBAN/CITY FLOODING WOULD BE POSSIBLE. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ UPDATE...AJ SHORT TERM...RIECK LONG TERM....RIECK AVIATION...AJ HYDROLOGY....DAS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
305 PM CDT SUN JUL 7 2013 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 305 PM CDT SUN JUL 7 2013 THE MAIN FOCUS GOING INTO TOMORROW IS WITH THE CHANCES FOR RAIN SHOWERS/THUNDERSTORMS AS A COLD FRONT MOVES THROUGH THE REGION. CURRENTLY...A HUMID AIR MASS IS IN PLACE AT THE SURFACE AS DEW POINTS CONTINUE TO RISE IN RESPONSE TO AN INCREASE OF LOW LEVEL MOISTURE TRANSPORT OUT OF THE GULF. SURFACE ANALYSIS SHOWS TWO COLD FRONTS IN THE VICINITY OF WESTERN MINNESOTA. THE FIRST ONE EXTENDS FROM NORTHERN WISCONSIN DOWN THROUGH SOUTH CENTRAL MINNESOTA AND EASTERN NEBRASKA. THE SECOND COLD FRONT IS JUST TO THE WEST OF THIS OTHER FRONT AND EXTENDS FROM A SURFACE LOW IN SOUTHERN MANITOBA DOWN THROUGH WESTERN MINNESOTA AND EASTERN SOUTH DAKOTA. WITH DEW POINTS IN THE LOW 70S BETWEEN THESE TWO FRONTS...07.19Z RAP ANALYSIS SHOWS AN AXIS OF 3000 J/KG OF SURFACE BASED CAPE. CONVECTION HAS INITIATED ALONG THE FIRST FRONT AND A LAKE BREEZE BOUNDARY NORTHWEST OF THE TWIN CITES AND DOWN ALONG THE FRONT. FURTHER ALOFT...MID LEVEL RIDGING EXTENDS FROM THE SOUTHERN PLAINS THROUGH THE UPPER GREAT LAKES. A MID LEVEL SHORT WAVE TROUGH IS CURRENT IN THE DAKOTAS AND WILL TRACK TO THE EAST THROUGH TONIGHT AND IS TIED TO THE SECONDARY COLD FRONT. THE ENVIRONMENT AHEAD OF THE COLD FRONTS APPEARS TO BE CAPPED AROUND 800MB...SO AM NOT EXPECTING ANY DEVELOPMENT OUT IN THE WARM SECTOR DESPITE THE HIGH CAPE ENVIRONMENT. THE MAIN CHANCES WILL BE AS THE FRONT AND WEAKENING MID LEVEL TROUGH COME THROUGH THIS EVENING AND OVERNIGHT. THE FRONT WILL THEN PUSH THROUGH AND STALL TO THE SOUTH OF THE REGION IN IOWA ON MONDAY. HAVE DROPPED THE PRECIPITATION CHANCES DOWN A LITTLE ON MONDAY AS IT LOOKS LIKE SURFACE TO UPPER LEVEL RIDGING WILL SETTLE IN FOR A BRIEF PERIOD AND KEEP THE REGION MORE ON THE DRY SIDE. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 305 PM CDT SUN JUL 7 2013 THE MAIN FOCUS IN THE LONG TERM IS ON MONDAY NIGHT INTO TUESDAY AND WITH WHERE A MESOSCALE CONVECTIVE SYSTEM WILL DEVELOP AND TRACK THROUGH ON TUESDAY MORNING. THE 07.12Z GUIDANCE CONTINUES TO GIVE SOME UNCERTAINTY WITH THE TRAJECTORY OF THIS MCS. THE GFS/NAM TAKE A MORE SOUTHERLY ROUTE ACROSS IOWA DUE TO THE LOW LEVEL JET/MOISTURE TRANSPORT ONLY REACHING EASTERN NEBRASKA BY 6Z TUESDAY. THE PERFERRED GUIDANCE IS FROM THE ECMWF/GEM SOLUTION WHICH PUSH THE LLJ NOSE INTO EASTERN SOUTH DAKOTA BY THIS TIME...AND DESPITE THE GEM/ECMWF SHOWING THE MAIN QPF STAYING WELL TO THE NORTH OF THE REGION TOWARD DULUTH...AM CONCERNED THAT THE MCS WOULD DEVELOP IN WESTERN MINNESOTA AND RUN EAST SOUTHEAST ALONG THE NOSE OF THE LOW LEVEL JET AND INSTABILITY GRADIENT. THIS IDEA FOLLOWS WELL WITH FORECAST CORFIDI VECTORS WHICH POINT TO THE SOUTHEAST TUESDAY MORNING...WHICH WOULD TAKE IT STRAIGHT THROUGH THE MIDDLE OF THE FORECAST AREA ALONG THE MINNESOTA/IOWA BORDER INTO WESTERN WISCONSIN. GIVEN THE MODEL DIFFERENCES...HAVE NOT HIT THE PRECIPITATION CHANCES TOO HIGH YET AND WILL HAVE TO SEE HOW THE PATTERN EVOLVES INTO TOMORROW. WITH THE INCREASING MOISTURE TRANSPORT AND POTENTIAL FOR HEAVY RAIN...FLASH FLOODING WILL BE A THREAT DESPITE THE RECENT DRY SPELL. DETAILS ARE OUTLINED IN THE HYDROLOGY AFD SECTION. THIS MCS CAUSES SOME HAVOC GOING INTO THE AFTERNOON ON TUESDAY AND WHAT THE SEVERE THUNDERSTORM CHANCES ARE AFTER ITS PASSAGE. IF THE SYSTEM TRACKS TO THE SOUTH...THEN IT LIKELY KEEPS THE MAIN WARM FRONT DOWN THERE AS WELL AND LIMITS THE SEVERE POTENTIAL. IF IT TRACKS THROUGH THE HEART OF THE FORECAST AREA...AS WE THINK IT MAY...THE QUESTION WILL BE HOW FAST DOES IT CLEAR AND ALLOW THE ENVIRONMENT TO RECHARGE BY PEAK HEATING. IF THE SYSTEM WERE TO CLEAR EARLY ENOUGH AND ALLOW FOR DESTABILIZATION BY LATE AFTERNOON OUR SEVERE THREAT WOULD BE FAIRLY HIGH DUE TO A VEERING 0-6KM SHEAR PROFILE...HIGH INSTABILITY...AND DEEP FORCING FROM A SURFACE LOW AND MID LEVEL TROUGH. WITH A LINGERING OUTFLOW BOUNDARY/WARM FRONT IN THE REGION...THE HAZARDS WOULD INCLUDE LARGE HAIL...FLASH FLOODING...DAMAGING WINDS AND THE POSSIBILITY OF A TORNADO OR TWO GIVEN THE HIGH 0-1KM SHEAR/HELICITY. THE THING IS...CONFIDENCE IS JUST NOT THERE YET TO LEAN ONE WAY OR ANOTHER UNTIL THERE IS BETTER CONCENSUS ON THE TRACK OF THE EARLY MORNING MCS. BEYOND THIS SYSTEM...IT LOOKS LIKE A DRY AND SEASONAL PERIOD THROUGH THE REST OF THE WEEK AS UPPER LEVEL RIDGING SETS UP ACROSS THE UPPER MISSISSIPPI RIVER VALLEY. A COLD FRONT WILL APPROACH THE REGION FROM THE WEST BY NEXT WEEKEND AND COULD BRING THE NEXT SHOT OF RAIN ALONG WITH IT. THERE ARE SOME TIMING DIFFERENCES BETWEEN THE 07.12Z GFS AND ECWMF WITH THIS FEATURE THAT WILL BE RUNNING INTO THE RIDGING. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY MORNING) ISSUED AT 1238 PM CDT SUN JUL 7 2013 AT MID DAY A TROUGH/FRONTAL BOUNDARY REMAINED WELL NORTHWEST OF THE FCST AREA. A MOIST/UNSTABLE AIR MASS WAS IN PLACE ALONG/AHEAD OF THE FRONT...WITH THE STRONGEST INSTABILITY NEAR THE FRONT. GENERALLY GOOD VFR EXPECTED THIS AFTERNOON...BUT SOME MOISTURE TRANSPORT INTO THE AREA AHEAD OF THE FRONT MAY GENERATE WDLY SCT SHRA/TSRA IN/ AROUND THE AREA LATER THIS AFTERNOON INTO THE EVENING. WITH LOWER CONFIDENCE IN THE CONVECTION CHANCES/COVERAGE THIS AFTERNOON...ONLY CARRIED A VCSH IN THE TAFS FROM 21-03Z FOR NOW. THE TROUGH/FRONT LOOKS TO SLIDE THRU THE AREA LATE THIS EVENING INTO THE OVERNIGHT HOURS. SHRA/TSRA CHANCES APPEAR QUITE LIMITED ONCE THE BOUNDARY PASSES. HOWEVER WITH WEAK PRESSURE GRADIENTS AND THE MOIST LOW LEVEL AIR MASS OVER THE AREA...LATE NIGHT/EARLY MORNING RADIATIONAL BR/FG BECOMES A CONCERN AT BOTH TAF SITES. UNTIL DETAILS BECOME CLEARER...CONTINUED THE MVFR/IFR BR MENTION AT BOTH SITES IN THE 09Z-13Z TIME-FRAME. LOWER LEVEL MOISTURE LINGERS OVER THE AREA BEHIND THE FRONT ON MON...WITH SOME CUMULUS IN THE 3K-4K FT RANGE EXPECTED. && .HYDROLOGY...TUESDAY ISSUED AT 305 PM CDT SUN JUL 7 2013 THE MAIN HYDRO CONCERNS COME IN ON TUESDAY AS A COMPLEX OF THUNDERSTORMS IS FORECAST TO TRACK THROUGH THE REGION. THE QUESTION IS WHERE AND WHEN WILL IT COME THROUGH? MOST OF THE MODEL GUIDANCE SUGGEST THAT THIS SYSTEM WILL FORM IN NORTHWEST NEBRASKA AND RUN EAST ACROSS IOWA MONDAY NIGHT INTO TUESDAY MORNING. WITH SHOWERS AND THUNDERSTORMS EXPECTED TO DEVELOP AHEAD OF THIS COMPLEX NORTH OF A WARM FRONT...THE POTENTIAL IS THERE FOR SOME HEAVY RAIN TO FALL. THANKFULLY...CONDITIONS HAVE BEEN DRY FOR THE PAST WEEK...SO FLASH FLOOD GUIDANCE HAS COME UP CONSIDERABLY AND THE SOIL SHOULD BE ABLE TO HANDLE THE EXCESS MOISTURE REASONABLY WELL FOR A PERIOD. THAT SAID...INCREASING PRECIPITABLE WATER VALUES AND LOW LEVEL MOISTURE TRANSPORT AIMING INTO THE REGION...EXPECT THAT HEAVY RAIN AND FLASH FLOODING IS POSSIBLE WITH SOME RENEWED RISES ON AREA RIVERS. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...HALBACH LONG TERM...HALBACH AVIATION...RRS HYDROLOGY...HALBACH
AREA FORECAST DISCUSSION
NWS TUCSON AZ
250 AM MST TUE JUL 9 2013 .SYNOPSIS...HIGH PRESSURE ALOFT WILL BE NEAR THE FOUR CORNERS REGION THIS WEEK. THUNDERSTORM COVERAGE WILL INCREASE THIS WEEK AS THE FLOW BECOMES MORE FAVORABLE TO PUSH STORMS INTO VALLEY LOCATIONS AND DEEPER MOISTURE ADVANCES FROM THE SOUTH AND SOUTHEAST. EXPECT SOMEWHAT LESS COVERAGE OF THUNDERSTORMS BY SUNDAY FOLLOWED BY ANOTHER INCREASE IN THUNDERSTORMS EARLY NEXT WEEK. && .DISCUSSION...EXPANSIVE MCS EXTENDED FROM SRN SONORA INTO SRN ARIZONA EARLY THIS MORNING. FAIRLY WIDESPREAD COVERAGE OF SHOWERS PRODUCING LIGHT RAINFALL...AND A FEW THUNDERSTORMS...WERE ONGOING ACROSS SE AZ. THIS ACTIVITY AS PER THE 09/07Z RUC HRRR WILL MOVE WWD ACROSS THE AREA THRU MID-MORNING...THEN DECREASE IN COVERAGE BY LATE MORNING ACROSS WRN PIMA COUNTY. THEREAFTER...ADDITIONAL SHOWERS AND THUNDERSTORMS ARE PROGGED TO DEVELOP EARLY THIS AFTERNOON MAINLY ACROSS THE MOUNTAINS AND ACROSS THE TOHONO OODHAM NATION. ADDITIONAL SHOWERS AND THUNDERSTORMS ARE THEN PROGGED TO ADVANCE SWWD FROM THE WHITE MOUNTAINS LATE THIS AFTERNOON. CONFIDENCE IN THIS FORECAST SCENARIO IS SOMEWHAT LOW GIVEN THE ONGOING MCS. AT ANY RATE...THE OFFICIAL FORECAST DEPICTS SCATTERED SHOWERS/TSTMS THIS AFTERNOON AND THIS EVENING FROM TUCSON EWD/SWD WITH LESSER PRECIP COVERAGE ACROSS WRN PIMA COUNTY. HAVE MAINTAINED A SLIGHT CHANCE OF SHOWERS/TSTMS ACROSS MUCH OF SE AZ LATE TONIGHT. WED-FRI... 09/00Z GFS/ECMWF WERE SIMILAR WITH DEPICTING A POTENTIAL MID TO HIGH-GRADE MONSOON REGIME. MID-LEVEL STEERING FLOW WILL BECOME INCREASINGLY SELY THUR-FRI AS THE FOUR CORNERS UPPER HIGH MOVES INTO THE CENTRAL CONUS PLAINS. SCATTERED TO PERHAPS NUMEROUS SHOWERS AND TSTMS SHOULD OCCUR WED-FRI PARTICULARLY DURING THE AFTERNOON AND EVENING HOURS. HAVE TRENDED POPS UPWARD GENERALLY ABOUT 10 PERCENT EACH FORECAST PERIOD. GFS PWATS PROGGED TO BE NEAR 1.80 INCHES ACROSS WRN PIMA COUNTY...AND ABOUT 1.30 INCHES NEAR THE NEW MEXICO BORDER. THE INCREASED MOISTURE MAY PRODUCE SOME HEAVY DOWNPOURS LEADING TO AT LEAST LOCALIZED FLOODING. SAT-MON... EXPECT THE COVERAGE OF SHOWERS/TSTMS TO REDUCE THIS WEEKEND AS MID- LEVEL DRYING IS PROGGED VIA THE GFS/ECMWF. SUNDAY SHOULD EXPERIENCE THE LEAST COVERAGE OF SHOWERS/TSTMS. THEREAFTER...PRECIP CHANCES WILL INCREASE NEXT MONDAY AS AN UPPER LEVEL LOW PRESSURE SYSTEM MOVES WWD ACROSS SRN TEXAS AND INTO CHIHUAHUA. THE OFFICIAL FORECAST HIGH TEMP TODAY AT THE TUCSON INTERNATIONAL AIRPORT IS 100 DEGREES. ACHIEVING 99 DEGREES OR COOLER WOULD END THE CURRENT 38 CONSECUTIVE DAY STREAK OF TRIPLE DIGIT TEMPS AT TIA. THEREAFTER...DAYTIME TEMPS WILL AVERAGE A FEW DEGS BELOW NORMAL WED-FRI FOLLOWED BY SLIGHTLY WARMER DAYTIME TEMPS THIS WEEKEND. && .AVIATION...VALID THRU 10/12Z... SCT -SHRA AND ISOLD -TSRA THIS MORNING THEN SCT TSRA/SHRA THIS AFTERNOON AND THIS EVENING. BRIEF WIND GUSTS OF 40-45 KTS INTO EARLY THIS EVENING WITH THE STRONGEST TSRA. ISOLD-SCT -SHRA LATE TONIGHT AND EARLY WEDNESDAY MORNING. OTHERWISE...VFR CONDITIONS AND SURFACE WIND GENERALLY LESS THAN 10 KTS THRU EARLY WEDNESDAY MORNING. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS. && .FIRE WEATHER...SCATTERED THUNDERSTORMS PRODUCING LOCALLY HEAVY RAINFALL WILL OCCUR THROUGH SATURDAY. SOMEWHAT DRIER AIR WILL LESS COVERAGE OF THUNDERSTORMS SUNDAY. THEREAFTER...AN UPPER LEVEL LOW PRESSURE SYSTEM APPROACHING FROM THE EAST WILL PROVIDE INCREASED THUNDERSTORM COVERAGE NEXT MONDAY. THE STRONGER THUNDERSTORMS INTO EARLY NEXT WEEK WILL PRODUCE GUSTY AND ERRATIC WINDS. OTHERWISE... NORMAL DIURNAL WIND TRENDS WILL OCCUR...WITH OCCASIONAL AFTERNOON GUSTINESS DUE TO DAYTIME HEATING. && .CLIMATE...THE HIGH TEMPERATURE AT TUCSON INTERNATIONAL AIRPORT REACHED 105 DEGREES MONDAY. THUS...MONDAY BECAME THE 38TH CONSECUTIVE DAY OF TRIPLE DIGIT TEMPS RECORDED AT TUCSON INTERNATIONAL AIRPORT. THIS IS THE THIRD LONGEST STREAK ON RECORD BEHIND 1987 AND 2005 (BOTH YEARS WITH 39 CONSECUTIVE DAYS). && .TWC WATCHES/WARNINGS/ADVISORIES...NONE. && $$ VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON BF
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
331 AM EDT TUE JUL 9 2013 .DISCUSSION... TODAY-TONIGHT...THERE WAS LITTLE CHANGE WITH THE 00Z GFS. IT WAS STILL SHOWING MID/UPPER LEVEL (TUTT) LOW PRESENTLY CENTERED NEAR ANDROS ISLAND PUSHING WEST NORTHWEST INTO THE SOUTHERN TIP OF THE FLORIDA PENINSULA. ATMOSPHERE WILL GRADUALLY MOISTEN...ESPECIALLY ACROSS THE SOUTH HALF OF THE AREA...WHILE WEAK VORT MAXIMA ROTATE AROUND THE LOW AND INCREASE LIFT. MOS POPS TODAY RANGE FROM 50 PERCENT IN THE FAR SOUTH TO 30 PERCENT ELSEWHERE. EVEN THOUGH THE GFS IS NOT GENERATING MUCH PRECIP...WILL GO WITH 40-50 PERCENT POPS ALONG THE TREASURE COAST SINCE THERE IS A DECENT SWATH OF SHOWERS ABOUT 100 MILES OFFSHORE SOUTH OF CANAVERAL. ELSEWHERE WILL STAY CLOSE TO THE PREVIOUS FORECAST...30 PERCENT...EXCEPT 20 PERCENT ALONG THE NORTH COAST WHERE THE GFS AND NAM GENERATE NO PRECIP. COOLING ALOFT IS SHOWN BY THE LATEST RAP ANALYSIS WITH LIGHTNING DETECTION EQUIPMENT SHOWING A FEW STRIKES EAST OF OUR COASTAL WATERS. THEREFORE EXPECT THAT AFTER A SEVERAL DAY HIATUS FROM LIGHTNING...THERE WILL BE A RETURN OF ISOLATED STORMS...ESPECIALLY INLAND AND OVER THE COASTAL WATERS. WEDNESDAY/THURSDAY...LITTLE CHANGE TO THE MID WEEK FORECAST AS TUTT CURRENTLY OVER THE BAHAMAS TRACKS ACROSS SOUTH FLORIDA ON WEDNESDAY...BEFORE BEING ABSORBED INTO LARGER SCALE UPPER TROUGH SWINGING THROUGH THE EASTERN CONUS ON THURSDAY. AT THE SAME TIME THE LOW LEVEL WESTERN ATLC RIDGE WILL SLIDE SOUTH IN RESPONSE TO THE FRONTAL TROUGH MOVING THROUGH THE EASTERN AND SOUTHEASTERN US...ENDING UP OVER OR JUST SOUTH OF THE AREA BY THURSDAY. FLOW WILL BE WEAK ENOUGH FOR BOTH SEA BREEZES TO FORM EACH AFTERNOON...WITH THE STEERING FLOW SHIFTING FROM SOUTH-SOUTHEAST ON WEDNESDAY TO SOUTHWEST ON THURSDAY AS THE AREA GETS SQUEEZED IN BETWEEN THE LARGER UPPER LEVEL TROUGH TO THE NORTH AND WESTERN ATLANTIC RIDGE NOSING IN. THE TUTT WILL BRING COLDER TEMPS ALOFT...ESPECIALLY ACROSS THE SOUTH...AND THE DEEPER MOISTURE WILL SUPPORT RAIN CHANCES AT OR JUST ABOVE NORMAL AT 40-50 PERCENT. FRIDAY/WEEKEND...UPPER LEVEL EAST COAST TROUGH DEEPENS ON FRIDAY...WITH THE SOUTHERN EXTENT OF THE TROUGH SPLITTING ON SATURDAY. THIS WILL LEAVE ANOTHER UPPER LEVEL LOW TO MEANDER SOUTHWESTWARDS ACROSS THE DEEP SOUTH AND WESTERN GULF OF MEXICO BY THE END OF THE WEEKEND. AT THE SURFACE...THE OFFICIAL TRACK FOR TS CHANTAL HAS IT MOVING THROUGH THE CENTRAL AND NORTHERN BAHAMAS FRIDAY AND SATURDAY WITH SOME QUESTION AS TO IF IT WILL SURVIVE THE EFFECTS OF LAND INTERACTION AND WIND SHEAR AFTER IT CROSSES HISPANIOLA LATE THURSDAY. WHAT INFLUENCE THE SYSTEM OR ITS REMNANTS WILL PLAY IN THE LOCAL WEATHER FOR THE WEEKEND IS STILL UNCLEAR. WILL KEEP POPS NEAR CLIMO THROUGH THE PERIOD AS FUTURE FORECASTS FOR CHANTAL UNFOLD. && .AVIATION... LOCAL MVFR IN ONSHORE MOVING SHOWERS MAINLY KMLB-KSUA WITH SLIGHT CHANCE FOR LIGHTNING IN THE VICINITY...ESPECIALLY THIS MORNING AND EARLY AFTERNOON. PROBABILITY FOR THESE CONDITIONS IN THE AFTERNOON FROM KISM/KMCO TO KSFB/KLEE ARE TOO LOW TO MENTION IN TAFS YET. && .MARINE... TODAY-TONIGHT...SURFACE RIDGE AXIS SETTLING INTO NORTH FLORIDA WILL REDUCE THE ONSHORE FLOW TO 10 KNOTS OR LESS. THERE WILL BE ISOLATED TO SCATTERED SHOWERS AND A FEW LIGHTNING STORMS... ESPECIALLY SOUTH OF CANAVERAL. WED-SAT...SOUTH-SOUTHEAST WINDS ON WEDNESDAY AND THURSDAY INTO THE END OF THE WEEK AS THE ATLANTIC RIDGE AXIS SLIDES INTO CENTRAL FLORIDA. SPEEDS AROUND 10-15KTS THROUGH THE PERIOD...WITH A STRONGER ONSHORE COMPONENT DEVELOPING NEARSHORE EACH AFTERNOON WITH THE EAST COAST SEA BREEZE. SEAS 2-4FT. FORECAST FROM SATURDAY ONWARDS BECOMES HIGHLY UNCERTAIN AS TC CHANTAL...OR ITS REMNANTS...ARE FORECAST TO BE IN THE CENTRAL AND NORTHERN BAHAMAS BY LATE FRIDAY INTO SATURDAY. WIND SPEEDS/DIRECTION AND SEAS WILL BE HIGHLY DEPENDENT ON HOW CHANTAL EVOLVES. && .PRELIMINARY POINT TEMPS/POPS... DAB 89 72 89 74 / 20 20 30 20 MCO 92 71 92 73 / 30 10 30 20 MLB 89 73 89 75 / 30 20 40 30 VRB 88 71 89 74 / 40 20 40 30 LEE 92 72 93 75 / 20 10 40 20 SFB 92 73 93 75 / 30 10 30 20 ORL 92 73 93 76 / 30 10 30 20 FPR 87 71 88 74 / 40 20 50 30 && .MLB WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. && $$ SHORT TERM/AVIATION...LASCODY LONG TERM....MOSES
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
437 AM CDT TUE JUL 9 2013 .DISCUSSION... 340 AM CDT SEVERE WEATHER AND HEAVY RAIN POTENTIAL THROUGH TONIGHT WAS WHAT MUCH OF THE ANALYSIS TIME WAS SPENT ON THIS MORNING. WHAT MAINLY WAS TRYING TO DO WAS LOCK DOWN A TIMING FOR AN IMPROVED SEVERE WEATHER THREAT /MID-AFTERNOON THROUGH EARLY OVERNIGHT THOUGH AIR MASS CAN ALLOW FOR ISOLATED SEVERE ANYTIME/...AND WHAT MAIN THREATS WOULD BE /WIND AND HEAVY RAIN/. OVERALL NO MAJOR CHANGES MADE TO THE FORECAST...JUST INCREASING POPS IN THOSE MOST FAVORED TIMES...RE-ORIENTING POPS SOME...AND REFINING RAINFALL AMOUNT FORECASTS. SYNOPSIS...A VERY SOUPY AIR MASS IS ENTRENCHED IN THE REGION THIS MORNING WITH MID 70S DEW POINTS ACROSS THE FORECAST AREA AND PWATS ON LAST EVES REGIONAL RAOBS AND EARLY MORNING OBJECTIVE ANALYSIS BEING AROUND 2 INCHES. NUMEROUS SHORT WAVE IMPULSES...MANY WITH ASSOCIATED CLUSTERS OF CONVECTION...ARE FOUND UPSTREAM ACROSS THE HIGH PLAINS AND OVER THE WESTERN CORN BELT ON GOES WATER VAPOR IMAGERY. THE PRIMARY UPPER LEVEL SHORT WAVE TROUGH WILL BE DIGGING INTO EASTERN MT SOON AFTER DAYBREAK AND WILL BE THE RESPONSIBLE PARTY FOR ENDING THIS MOIST AIR MASS...AT LEAST TEMPORARILY BY LATER WED. AT THE SURFACE A FAIRLY DIFFUSE GRADIENT EXISTS EARLY TODAY WITH A WEAK STATIONARY BOUNDARY NEAR THE STATE LINE. THE WEAK FLOW HAS ALLOWED FOR LOW CLOUDS AND FOG TO BE EXPANDING THEIR WAY SOUTHWARD DOWN LAKE MI AIDED BY AMBIENT DEW POINTS EXCEEDING THE WATER TEMPS BY SEVERAL DEGREES. THE PRIMARY SURFACE FRONT IS TAKING SHAPE ACROSS THE HIGH PLAINS AND WILL DEVELOP INTO A COOL FRONT LATER TODAY AS SURFACE CYCLOGENESIS OCCURS THROUGH NORTHERN MN INTO WESTERN ONTARIO BY THIS EVE. THIS FRONT WILL MOVE INTO THE FORECAST AREA LATE TONIGHT INTO EARLY WED MORNING. MULTIPLE ROUNDS OF CONVECTION ARE LIKELY AHEAD OF THIS. MODEL PREFERENCE...THE RAP AND HRRR GUIDANCE HAVE A GOOD REPRESENTATION OF ONGOING CONVECTION. THESE HAVE THE SUPPORT OF SEVERAL OTHER CONVECTIVE ALLOWING MODELS AND HAVE BEEN GUIDED ON THROUGH MID-AFTERNOON. AFTERWORDS HAVE LEANED TOWARD THE SLIGHTLY SLOWER 09.00 NAM THAN GFS. THIS MORNING...REMNANT MCV/SHORT WAVE ENTERING WESTERN IL EARLY THIS MORNING HAS BEGUN TO INCREASE RADAR ECHOES ACROSS CENTRAL IL AND THIS TREND IS LIKELY TO CONTINUE WITH SCATTERED CONVECTION FAVORED DUE TO MODERATE TO HIGH ELEVATED INSTABILITY. NOT A PARTICULARLY STRONG LOW-LEVEL JET OR ONE WITH HUGE MOISTURE TRANSPORT THIS MORNING...DUE TO STILL BEING A GOOD DISTANCE AHEAD OF MID-LEVEL HEIGHT FALLS. SO MORNING SCATTERED TO NUMEROUS SHOWERS/STORMS ACROSS CENTRAL IL MAY STRUGGLE TO PROGRESS NORTH/NORTHEAST AT LEAST AT ANY GOOD CLIP OF SPEED. THUS ROCKFORD TO CHICAGO HAVE POPS ONLY AT THE CHANCE LEVEL...AND MORE SO BASED ON ISOLATED CELLS DEVELOPING IN THE BROAD WAA AND HIGH PWAT REGIME. WITH SUCH HIGH PWATS AS YESTERDAY MORNING SHOWED...LOCALLY HEAVY RAINFALL WOULD BE THE PRIMARILY ASPECT TO KEEP AN EYE ON WITH THESE MORNING AND EARLY AFTERNOON STORMS. AS FOR EARLY MORNING FOG/STRATUS THAT HAS BEEN DEVELOPING IN PLACES...ONSHORE FLOW MAY FAVOR PATCHES OF THIS TO CONTINUE THROUGH MID OR EVEN LATE MORNING ACROSS NORTHEAST IL AND FAR NORTHWEST IN...STUNTING A TEMPERATURE CLIMB INITIALLY. OTHERWISE THIS LOOKS LIKE IT SHOULD BEGIN DISSIPATING/RETREATING NORTH AFTER THAT TIME. CONFIDENCE...HIGH. THIS AFTERNOON THROUGH TONIGHT...THE END OF THE RAP RUN AGREES CLOSELY WITH THE NAM IN TAKING THE SHORT WAVES AND ASSOCIATED 500 AND 700MB SPEED MAXS ACROSS THE DAKOTAS AND NORTHERN NEBRASKA EARLY THIS MORNING AND TRACKING THAT EAST INTO SOUTHERN WI AND NORTHERN IL BY MID TO LATE AFTERNOON. ON THE SYNOPTIC SCALE AT THAT TIME...THE LOW-LEVEL JET AND MOISTURE TRANSPORT WILL ALSO BE ON THE EXPANSE FROM MO INTO EASTERN IA/WESTERN IL. MIXED LAYER INSTABILITY WILL BE HIGH OVER THIS AREA INCLUDING THE WESTERN FORECAST AREA GIVEN TEMPS IN THE UPPER 80S TO LOWER 90S. WHILE SOME FORM OF MCS OR MULTIPLE CLUSTERS ARE PROBABLE TO BE MOVING EASTWARD OVER SOUTHERN WI/FAR NORTHERN IL DURING THE AFTERNOON WITH THE SHORT WAVES...DEVELOPMENT IS FAVORED TO WORK ITS WAY SOUTH AND BACK TO THE SOUTHWEST FROM THERE IN THE MOIST UNSTABLE AIR MASS DURING THE MID-AFTERNOON. DEEP LAYER SHEAR IS ANTICIPATED TO BE INCREASING TO AROUND 30-35 KT BY LATE AFTERNOON WITH ORGANIZED STORMS EXPECTED TO BE ALL WORKING THEIR WAY EASTWARD. AS THE PRIMARY UPPER TROUGH APPROACHES THIS EVENING...LARGER SCALE ASCENT AND FORCING IS LIKELY TO CONTINUE REGIONAL DEVELOPMENT OF STORMS NEAR AND AHEAD OF THE SURFACE FRONT. SO WHILE THERE LOOKS TO BE TWO PRIMARY FOCUSES FOR STORMS THIS AFTERNOON INTO TONIGHT...THERE IS NOT REALLY ANTICIPATED TO BE MUCH OF A BREAK AND THE HIGH PWAT AND UNSTABLE AIR SHOULD ALLOW FOR PLENTY OF COVERAGE. THAT COVERAGE MAY INITIALLY BE A LITTLE LIMITED DEPENDING ON DEBRIS CLOUD COVER BUT IS ANTICIPATED TO BE ITS HIGHEST LATER THIS AFTERNOON THROUGH EARLY OVERNIGHT. THE MOST FAVORED MODE FOR STORMS IS MULTICELL AND SEGMENTS CAPABLE OF SCATTERED DAMAGING WINDS...ESPECIALLY AS THE STRONGER MID-LEVEL JET OVERRIDES THE FRONT THIS EVENING INTO EARLY OVERNIGHT. SOME DEVELOPMENT THIS AFTERNOON THROUGH MID-EVE HAS THE POTENTIAL TO BE SUPERCELLULAR. THE LOW-LEVEL SHEAR IS FAIRLY ANEMIC MUCH OF THIS AFTERNOON /AOB 10 KT/ BUT QUICKLY INCREASES LATE INTO EARLY THIS EVE DUE TO THE DEEPENING LOW AND INCREASING LLJ. THIS WILL HELP FAVOR COLD POOL SUSTAINABILITY AND DOES PRESENT AT LEAST SOME TORNADO THREAT...ALTHOUGH IT LOOKS LIKE SURFACE WINDS MAY BE BACKED MORE TO THE WEST OF THE FORECAST AREA IMMEDIATELY AHEAD OF A SUBTLE SECONDARY SURFACE LOW MOVING UP THE FRONT. SO THE PRIMARY THREAT WILL REMAIN WIND AND OF COURSE HEAVY RAIN WITH EXTREMELY EFFICIENT RAIN PRODUCTION WILL OCCUR IN ANY STORMS TODAY AND TONIGHT. EVEN THOUGH FORWARD PROPAGATION OF STORMS SHOULD BE ON THE INCREASE TONIGHT...SO WILL DEEP MOISTURE REPLENISHMENT AND SIMPLY PUT THE ABSOLUTE MOISTURE IS SO HIGH IT WONT TAKE MUCH TO GET HIGH RAINFALL RATES SUCH AS WE SAW YESTERDAY MORNING. THERE WILL LIKELY BE SWATHS OF RAINFALL IN EXCESS OF ONE TO TWO INCHES ACROSS THE IMMEDIATE REGION...BUT WHERE EXACTLY THEY OCCUR IS TOO CHALLENGING TO LOCK DOWN. DEBATED ON A FLASH FLOOD WATCH BUT FEEL THE THREAT IS TOO LOCALIZED AT THIS TIME FOR A WATCH. CONFIDENCE...MEDIUM. WEDNESDAY...ONGOING SCATTERED SHOWERS AND STORMS ARE POSSIBLE ACROSS MAINLY THE SOUTHERN AND EASTERN FORECAST AREA IN THE MORNING WITH STILL AT LEAST SOME HEAVY RAIN THREAT. WARM 850-925MB AIR BEHIND THE SURFACE WIND SHIFT WILL STILL FAVORED HIGHS IN THE MID TO POSSIBLY EVEN UPPER 80S IN THE SOUTH. DRIER AIR WILL GRADUALLY FILTER IN DURING THE LATER AFTERNOON AND NIGHT PER GUIDANCE. CONFIDENCE...HIGH. THURSDAY THROUGH MONDAY...PRIMARILY DRY WEATHER IS EXPECTED OVER THE AREA ALTHOUGH THE TREND IN BOTH THE EC AND GFS THEIR LAST MULTIPLE RUNS SUPPORTS WARMER TEMPERATURES THIS WEEKEND WITH MID AND MAYBE EVEN UPPER 80S SEEN. HAVE COLLABORATED AND LEANED TOWARD THE WARMER MEX GUIDANCE. THE PATTERN STILL APPEARS BLOCKED JUST WITH THE AREA MORE UNDER THE INFLUENCE OF THE UPPER RIDGE TO THE WEST. MTF && .HYDROLOGY... 410 AM CDT THE VERY MOIST AIR MASS WILL SUPPORT EFFICIENT RAINFALL PRODUCTION FROM ANY THUNDERSTORMS TODAY AND TONIGHT. THIS MAY PRESENT FLASH FLOODING ESPECIALLY ON THE LOCAL LEVEL AS OPPOSED TO ANY WIDESPREAD THREAT. THAT AND THE FACT THERE IS NOT A GREAT SET UP FOR TRUE TRAINING STORMS IS WHY NO FLASH FLOOD WATCH AT THIS TIME. HOWEVER...IF ANY STORMS ARE IN A PARTICULARLY VULNERABLE AREA...SUCH AS A METRO OR A QUICK-RESPONDING WATERSHED...IT COULD BE TROUBLE. THESE TYPE OF HIGH RATES WERE ALREADY SEEN YESTERDAY MORNING WITH A NARROW SWATH OF ONE AND A HALF TO ESTIMATED THREE PLUS INCHES OF RAIN SEEN FROM RE-FIRING STORMS IN THE WEST CHICAGO METRO. HIGH RESOLUTION MODEL GUIDANCE INDICATES SUCH SWATHS ARE PROBABLE IN THE REGION THIS AFTERNOON INTO TONIGHT ALTHOUGH WHERE IS STILL UNCERTAIN. THE GENERAL RAINFALL FORECAST IS FOR MOST AREAS TO SEE AROUND AN INCH OR A LITTLE OVER BY WEDNESDAY MORNING. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 09Z... * FOG WITH REDUCED VIS OF 4SM-6SM DEVELOPING EARLY THIS MORNING. * SHOWERS WITH POSSIBLE TS REDEVELOPING LATER THIS MORNING AND CONTINUING THROUGH LATE MORNING. * REDEVELOPMENT OF SHOWERS/TS ONCE AGAIN LATER THIS AFTERNOON. * MORE WIDESPREAD SHOWERS/TS EXPECTED TO MOVE ACROSS THE TERMINALS LATER THIS EVENING AND OVERNIGHT. * COMPLEX WIND FORECAST WITH VARIABLE/LIGHT WINDS BECOMING NORTHEAST LATER THIS MORNING...THEN SHIFTING MORE SOUTHERLY LATER THIS AFTERNOON AND EVENING. RODRIGUEZ //DISCUSSION...UPDATED 06Z... A VERY COMPLEX FORECAST PERIOD FOR THE TERMINALS OVER THE NEXT 24 HOURS AS VARYING WEATHER CONDITIONS AT MULTIPLE TIMES COULD HAVE IMPACTS ON THE TERMINALS. IN THE NEAR TERM...THE SHOWERS/TS WHICH HAD DEVELOPED ACROSS NORTHEAST ILLINOIS AND OVER SOUTHERN LAKE MICHIGAN HAVE SINCE DIMINISHED EARLY THIS MORNING...AND THINK ANY FURTHER DEVELOPMENT SHOULD REMAIN VERY ISOLATED AND BRIEF OUTSIDE OF THE TERMINALS. WITH EXPECTED CLEARING...LIGHT WINDS AND A VERY MOIST ENVIRONMENT SHOULD SUPPORT FOG DEVELOPMENT OVER THE TERMINALS THIS MORNING WITH VIS RESTRICTION EXPECTED. OUTSIDE OF THIS DEVELOPMENT...A LIGHT NORTHERLY WIND OVER THE LAKE WITH LOW CEILINGS AND VIS FURTHER NORTH TOWARDS THE MIDDLE PART OF THE LAKE RAISES SOME CONCERNS FOR POTENTIAL LOWER CEILINGS AND FOG TO MOVE ACROSS THE TERMINALS NEAR THE LAKE...ORD/MDW/GYY. EVEN IF THE CLOUDS/FOG TO THE NORTH DONT QUITE MAKE IT THIS FAR SOUTH...COOLER AIR MOVING INTO A VERY MOIST ENVIRONMENT COULD SUPPORT LOW CLOUD/FOG DEVELOPMENT NEAR THE LAKE SHORE ANYWAYS. CONFIDENCE IS LOW WITH REGARDS TO THE POTENTIAL BUT WILL NEED TO MONITOR THIS AND ADJUST AS NEEDED. EXPECT REDEVELOPMENT OF SHOWERS/TS LATER THIS MORNING AS ANOTHER MID LEVEL DISTURBANCE APPROACHES FROM THE WEST...WITH THIS SCATTERED DEVELOPMENT POSSIBLY CONTINUING THROUGH MID DAY. ALTHOUGH SHOULD SEE A DIMINISHING TREND INTO THE EARLY AFTERNOON...REDEVELOPMENT IN AND AROUND THE TERMINALS WILL ONCE AGAIN BE POSSIBLE LATE THIS AFTERNOON THROUGH THE EARLY EVENING. MORE WIDESPREAD SHOWERS/THUNDERSTORMS ARE EXPECTED TO MOVE ACROSS THE TERMINALS LATE THIS EVENING AND OVERNIGHT BEFORE EXITING EARLY WEDNESDAY MORNING. THE WIND FORECAST IS RATHER COMPLEX AS A WEAK GRADIENT WITH SEVERAL BOUNDARIES MOVING ACROSS THE AREA ARE IN PLACE. WITH THESE FEATURES IN PLACE...WIND DIRECTION AND SPEED WILL LIKELY RANGE SUBSTANTIALLY FROM TERMINAL TO THE OTHER. LIGHT AND VARIABLE WINDS FOR ALL OF THE TERMINALS EARLY THIS MORNING WILL PICK UP LATER THIS MORNING WITH RFD THE ONLY SITE OBSERVING A MORE SOUTHERLY DIRECTION EARLY ON. THE OTHER SITES SHOULD HOLD ONTO A NORTHEAST DIRECTION LATER THIS MORNING...LIGHT AT FIRST BUT PICKING UP IN SPEEDS. THEN AS THE GRADIENT TIGHTENS OUT AHEAD OF AN APPROACHING SYSTEM...DO EXPECT A TRANSITION TO MORE OF A SOUTHERLY DIRECTION TO OCCUR LATER THIS AFTERNOON AND THEN CONTINUE INTO THE EVENING HOURS. RODRIGUEZ //ORD AND MDW CONFIDENCE...UPDATED 09Z... * MEDIUM CONFIDENCE WITH FOG/REDUCED VIS. * LOW MEDIUM CONFIDENCE WITH SHOWERS/TS LATER THIS MORNING. * MEDIUM CONFIDENCE WITH SHOWERS/TS THIS AFTERNOON. * MEDIUM CONFIDENCE WITH SHOWERS/TS LATER THIS EVENING/OVERNIGHT. * LOW/MEDIUM CONFIDENCE ON WIND SPEED/DIRECTION. RODRIGUEZ //OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z... * WEDNESDAY...CHANCE OF TSRA...MAINLY IN THE MORNING. * THURSDAY THROUGH SUNDAY...DRY/VFR. && .MARINE... 427 AM CDT MAIN FORECAST CONCERN IN THE NEAR TERM IS FOR AREAS ACROSS THE NORTHERN TWO THIRDS OF THE LAKE...WHERE DENSE FOG HAS SETTLED IN. EXPECT THIS FOG TO PERSIST AT LEAST THROUGH THE AFTERNOON WITH CURRENT THINKING THAT THIS FOG WILL CHURN UP WITH APPROACHING PRECIP. ALTHOUGH CONFIDENCE IS LOW...AND ITS POSSIBLE THE CURRENT DENSE FOG ADVISORY IN PLACE THROUGH THE AFTERNOON COULD NEED TO BE EXTENDED THROUGH THE EVENING. THERE IS ALSO POTENTIAL FOR THE MORE DENSE FOG TO PUSH FURTHER DOWN THE LAKE EARLY THIS MORNING...BEFORE WINDS BEGIN TO SHIFT AND BRING A STOP TO THIS SOUTHWARD MOVING AREA OF FOG. CURRENT LIGHT NORTHERLY WINDS IN PLACE ACROSS THE LAKE WILL TURN MORE SOUTHERLY THROUGHOUT TODAY AS THE NEXT SYSTEM APPROACHES FROM THE WEST. AS THIS SYSTEM THEN PROGRESSES ACROSS THE LAKE TONIGHT...EXPECT SOUTHWEST WINDS TO BECOME MORE WESTERLY WHILE INCREASING MORE TOWARDS THE 10 TO 20 KT RANGE. THEN AS HIGH PRESSURE SLOWLY BUILDS EAST TOWARDS THE LAKE...EXPECT GENERALLY NORTHERLY WINDS THROUGH THE REST OF THE WORK WEEK. RODRIGUEZ && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...DENSE FOG ADVISORY...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565- LMZ567-LMZ669-LMZ671-LMZ673-LMZ868-LMZ870-LMZ872-LMZ874 UNTIL 3 PM TUESDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
425 AM CDT TUE JUL 9 2013 .DISCUSSION... 340 AM CDT SEVERE WEATHER AND HEAVY RAIN POTENTIAL THROUGH TONIGHT WAS WHAT MUCH OF THE ANALYSIS TIME WAS SPENT ON THIS MORNING. WHAT MAINLY WAS TRYING TO DO WAS LOCK DOWN A TIMING FOR AN IMPROVED SEVERE WEATHER THREAT /MID-AFTERNOON THROUGH EARLY OVERNIGHT THOUGH AIR MASS CAN ALLOW FOR ISOLATED SEVERE ANYTIME/...AND WHAT MAIN THREATS WOULD BE /WIND AND HEAVY RAIN/. OVERALL NO MAJOR CHANGES MADE TO THE FORECAST...JUST INCREASING POPS IN THOSE MOST FAVORED TIMES...RE-ORIENTING POPS SOME...AND REFINING RAINFALL AMOUNT FORECASTS. SYNOPSIS...A VERY SOUPY AIR MASS IS ENTRENCHED IN THE REGION THIS MORNING WITH MID 70S DEW POINTS ACROSS THE FORECAST AREA AND PWATS ON LAST EVES REGIONAL RAOBS AND EARLY MORNING OBJECTIVE ANALYSIS BEING AROUND 2 INCHES. NUMEROUS SHORT WAVE IMPULSES...MANY WITH ASSOCIATED CLUSTERS OF CONVECTION...ARE FOUND UPSTREAM ACROSS THE HIGH PLAINS AND OVER THE WESTERN CORN BELT ON GOES WATER VAPOR IMAGERY. THE PRIMARY UPPER LEVEL SHORT WAVE TROUGH WILL BE DIGGING INTO EASTERN MT SOON AFTER DAYBREAK AND WILL BE THE RESPONSIBLE PARTY FOR ENDING THIS MOIST AIR MASS...AT LEAST TEMPORARILY BY LATER WED. AT THE SURFACE A FAIRLY DIFFUSE GRADIENT EXISTS EARLY TODAY WITH A WEAK STATIONARY BOUNDARY NEAR THE STATE LINE. THE WEAK FLOW HAS ALLOWED FOR LOW CLOUDS AND FOG TO BE EXPANDING THEIR WAY SOUTHWARD DOWN LAKE MI AIDED BY AMBIENT DEW POINTS EXCEEDING THE WATER TEMPS BY SEVERAL DEGREES. THE PRIMARY SURFACE FRONT IS TAKING SHAPE ACROSS THE HIGH PLAINS AND WILL DEVELOP INTO A COOL FRONT LATER TODAY AS SURFACE CYCLOGENESIS OCCURS THROUGH NORTHERN MN INTO WESTERN ONTARIO BY THIS EVE. THIS FRONT WILL MOVE INTO THE FORECAST AREA LATE TONIGHT INTO EARLY WED MORNING. MULTIPLE ROUNDS OF CONVECTION ARE LIKELY AHEAD OF THIS. MODEL PREFERENCE...THE RAP AND HRRR GUIDANCE HAVE A GOOD REPRESENTATION OF ONGOING CONVECTION. THESE HAVE THE SUPPORT OF SEVERAL OTHER CONVECTIVE ALLOWING MODELS AND HAVE BEEN GUIDED ON THROUGH MID-AFTERNOON. AFTERWORDS HAVE LEANED TOWARD THE SLIGHTLY SLOWER 09.00 NAM THAN GFS. THIS MORNING...REMNANT MCV/SHORT WAVE ENTERING WESTERN IL EARLY THIS MORNING HAS BEGUN TO INCREASE RADAR ECHOES ACROSS CENTRAL IL AND THIS TREND IS LIKELY TO CONTINUE WITH SCATTERED CONVECTION FAVORED DUE TO MODERATE TO HIGH ELEVATED INSTABILITY. NOT A PARTICULARLY STRONG LOW-LEVEL JET OR ONE WITH HUGE MOISTURE TRANSPORT THIS MORNING...DUE TO STILL BEING A GOOD DISTANCE AHEAD OF MID-LEVEL HEIGHT FALLS. SO MORNING SCATTERED TO NUMEROUS SHOWERS/STORMS ACROSS CENTRAL IL MAY STRUGGLE TO PROGRESS NORTH/NORTHEAST AT LEAST AT ANY GOOD CLIP OF SPEED. THUS ROCKFORD TO CHICAGO HAVE POPS ONLY AT THE CHANCE LEVEL...AND MORE SO BASED ON ISOLATED CELLS DEVELOPING IN THE BROAD WAA AND HIGH PWAT REGIME. WITH SUCH HIGH PWATS AS YESTERDAY MORNING SHOWED...LOCALLY HEAVY RAINFALL WOULD BE THE PRIMARILY ASPECT TO KEEP AN EYE ON WITH THESE MORNING AND EARLY AFTERNOON STORMS. AS FOR EARLY MORNING FOG/STRATUS THAT HAS BEEN DEVELOPING IN PLACES...ONSHORE FLOW MAY FAVOR PATCHES OF THIS TO CONTINUE THROUGH MID OR EVEN LATE MORNING ACROSS NORTHEAST IL AND FAR NORTHWEST IN...STUNTING A TEMPERATURE CLIMB INITIALLY. OTHERWISE THIS LOOKS LIKE IT SHOULD BEGIN DISSIPATING/RETREATING NORTH AFTER THAT TIME. CONFIDENCE...HIGH. THIS AFTERNOON THROUGH TONIGHT...THE END OF THE RAP RUN AGREES CLOSELY WITH THE NAM IN TAKING THE SHORT WAVES AND ASSOCIATED 500 AND 700MB SPEED MAXS ACROSS THE DAKOTAS AND NORTHERN NEBRASKA EARLY THIS MORNING AND TRACKING THAT EAST INTO SOUTHERN WI AND NORTHERN IL BY MID TO LATE AFTERNOON. ON THE SYNOPTIC SCALE AT THAT TIME...THE LOW-LEVEL JET AND MOISTURE TRANSPORT WILL ALSO BE ON THE EXPANSE FROM MO INTO EASTERN IA/WESTERN IL. MIXED LAYER INSTABILITY WILL BE HIGH OVER THIS AREA INCLUDING THE WESTERN FORECAST AREA GIVEN TEMPS IN THE UPPER 80S TO LOWER 90S. WHILE SOME FORM OF MCS OR MULTIPLE CLUSTERS ARE PROBABLE TO BE MOVING EASTWARD OVER SOUTHERN WI/FAR NORTHERN IL DURING THE AFTERNOON WITH THE SHORT WAVES...DEVELOPMENT IS FAVORED TO WORK ITS WAY SOUTH AND BACK TO THE SOUTHWEST FROM THERE IN THE MOIST UNSTABLE AIR MASS DURING THE MID-AFTERNOON. DEEP LAYER SHEAR IS ANTICIPATED TO BE INCREASING TO AROUND 30-35 KT BY LATE AFTERNOON WITH ORGANIZED STORMS EXPECTED TO BE ALL WORKING THEIR WAY EASTWARD. AS THE PRIMARY UPPER TROUGH APPROACHES THIS EVENING...LARGER SCALE ASCENT AND FORCING IS LIKELY TO CONTINUE REGIONAL DEVELOPMENT OF STORMS NEAR AND AHEAD OF THE SURFACE FRONT. SO WHILE THERE LOOKS TO BE TWO PRIMARY FOCUSES FOR STORMS THIS AFTERNOON INTO TONIGHT...THERE IS NOT REALLY ANTICIPATED TO BE MUCH OF A BREAK AND THE HIGH PWAT AND UNSTABLE AIR SHOULD ALLOW FOR PLENTY OF COVERAGE. THAT COVERAGE MAY INITIALLY BE A LITTLE LIMITED DEPENDING ON DEBRIS CLOUD COVER BUT IS ANTICIPATED TO BE ITS HIGHEST LATER THIS AFTERNOON THROUGH EARLY OVERNIGHT. THE MOST FAVORED MODE FOR STORMS IS MULTICELL AND SEGMENTS CAPABLE OF SCATTERED DAMAGING WINDS...ESPECIALLY AS THE STRONGER MID-LEVEL JET OVERRIDES THE FRONT THIS EVENING INTO EARLY OVERNIGHT. SOME DEVELOPMENT THIS AFTERNOON THROUGH MID-EVE HAS THE POTENTIAL TO BE SUPERCELLULAR. THE LOW-LEVEL SHEAR IS FAIRLY ANEMIC MUCH OF THIS AFTERNOON /AOB 10 KT/ BUT QUICKLY INCREASES LATE INTO EARLY THIS EVE DUE TO THE DEEPENING LOW AND INCREASING LLJ. THIS WILL HELP FAVOR COLD POOL SUSTAINABILITY AND DOES PRESENT AT LEAST SOME TORNADO THREAT...ALTHOUGH IT LOOKS LIKE SURFACE WINDS MAY BE BACKED MORE TO THE WEST OF THE FORECAST AREA IMMEDIATELY AHEAD OF A SUBTLE SECONDARY SURFACE LOW MOVING UP THE FRONT. SO THE PRIMARY THREAT WILL REMAIN WIND AND OF COURSE HEAVY RAIN WITH EXTREMELY EFFICIENT RAIN PRODUCTION WILL OCCUR IN ANY STORMS TODAY AND TONIGHT. EVEN THOUGH FORWARD PROPAGATION OF STORMS SHOULD BE ON THE INCREASE TONIGHT...SO WILL DEEP MOISTURE REPLENISHMENT AND SIMPLY PUT THE ABSOLUTE MOISTURE IS SO HIGH IT WONT TAKE MUCH TO GET HIGH RAINFALL RATES SUCH AS WE SAW YESTERDAY MORNING. THERE WILL LIKELY BE SWATHS OF RAINFALL IN EXCESS OF ONE TO TWO INCHES ACROSS THE IMMEDIATE REGION...BUT WHERE EXACTLY THEY OCCUR IS TOO CHALLENGING TO LOCK DOWN. DEBATED ON A FLASH FLOOD WATCH BUT FEEL THE THREAT IS TOO LOCALIZED AT THIS TIME FOR A WATCH. CONFIDENCE...MEDIUM. WEDNESDAY...ONGOING SCATTERED SHOWERS AND STORMS ARE POSSIBLE ACROSS MAINLY THE SOUTHERN AND EASTERN FORECAST AREA IN THE MORNING WITH STILL AT LEAST SOME HEAVY RAIN THREAT. WARM 850-925MB AIR BEHIND THE SURFACE WIND SHIFT WILL STILL FAVORED HIGHS IN THE MID TO POSSIBLY EVEN UPPER 80S IN THE SOUTH. DRIER AIR WILL GRADUALLY FILTER IN DURING THE LATER AFTERNOON AND NIGHT PER GUIDANCE. CONFIDENCE...HIGH. THURSDAY THROUGH MONDAY...PRIMARILY DRY WEATHER IS EXPECTED OVER THE AREA ALTHOUGH THE TREND IN BOTH THE EC AND GFS THEIR LAST MULTIPLE RUNS SUPPORTS WARMER TEMPERATURES THIS WEEKEND WITH MID AND MAYBE EVEN UPPER 80S SEEN. HAVE COLLABORATED AND LEANED TOWARD THE WARMER MEX GUIDANCE. THE PATTERN STILL APPEARS BLOCKED JUST WITH THE AREA MORE UNDER THE INFLUENCE OF THE UPPER RIDGE TO THE WEST. MTF && .HYDROLOGY... 410 AM CDT THE VERY MOIST AIR MASS WILL SUPPORT EFFICIENT RAINFALL PRODUCTION FROM ANY THUNDERSTORMS TODAY AND TONIGHT. THIS MAY PRESENT FLASH FLOODING ESPECIALLY ON THE LOCAL LEVEL AS OPPOSED TO ANY WIDESPREAD THREAT. THAT AND THE FACT THERE IS NOT A GREAT SET UP FOR TRUE TRAINING STORMS IS WHY NO FLASH FLOOD WATCH AT THIS TIME. HOWEVER...IF ANY STORMS ARE IN A PARTICULARLY VULNERABLE AREA...SUCH AS A METRO OR A QUICK-RESPONDING WATERSHED...IT COULD BE TROUBLE. THESE TYPE OF HIGH RATES WERE ALREADY SEEN YESTERDAY MORNING WITH A NARROW SWATH OF ONE AND A HALF TO ESTIMATED THREE PLUS INCHES OF RAIN SEEN FROM RE-FIRING STORMS IN THE WEST CHICAGO METRO. HIGH RESOLUTION MODEL GUIDANCE INDICATES SUCH SWATHS ARE PROBABLE IN THE REGION THIS AFTERNOON INTO TONIGHT ALTHOUGH WHERE IS STILL UNCERTAIN. THE GENERAL RAINFALL FORECAST IS FOR MOST AREAS TO SEE AROUND AN INCH OR A LITTLE OVER BY WEDNESDAY MORNING. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 09Z... * FOG WITH REDUCED VIS OF 4SM-6SM DEVELOPING EARLY THIS MORNING. * SHOWERS WITH POSSIBLE TS REDEVELOPING LATER THIS MORNING AND CONTINUING THROUGH LATE MORNING. * REDEVELOPMENT OF SHOWERS/TS ONCE AGAIN LATER THIS AFTERNOON. * MORE WIDESPREAD SHOWERS/TS EXPECTED TO MOVE ACROSS THE TERMINALS LATER THIS EVENING AND OVERNIGHT. * COMPLEX WIND FORECAST WITH VARIABLE/LIGHT WINDS BECOMING NORTHEAST LATER THIS MORNING...THEN SHIFTING MORE SOUTHERLY LATER THIS AFTERNOON AND EVENING. RODRIGUEZ //DISCUSSION...UPDATED 06Z... A VERY COMPLEX FORECAST PERIOD FOR THE TERMINALS OVER THE NEXT 24 HOURS AS VARYING WEATHER CONDITIONS AT MULTIPLE TIMES COULD HAVE IMPACTS ON THE TERMINALS. IN THE NEAR TERM...THE SHOWERS/TS WHICH HAD DEVELOPED ACROSS NORTHEAST ILLINOIS AND OVER SOUTHERN LAKE MICHIGAN HAVE SINCE DIMINISHED EARLY THIS MORNING...AND THINK ANY FURTHER DEVELOPMENT SHOULD REMAIN VERY ISOLATED AND BRIEF OUTSIDE OF THE TERMINALS. WITH EXPECTED CLEARING...LIGHT WINDS AND A VERY MOIST ENVIRONMENT SHOULD SUPPORT FOG DEVELOPMENT OVER THE TERMINALS THIS MORNING WITH VIS RESTRICTION EXPECTED. OUTSIDE OF THIS DEVELOPMENT...A LIGHT NORTHERLY WIND OVER THE LAKE WITH LOW CEILINGS AND VIS FURTHER NORTH TOWARDS THE MIDDLE PART OF THE LAKE RAISES SOME CONCERNS FOR POTENTIAL LOWER CEILINGS AND FOG TO MOVE ACROSS THE TERMINALS NEAR THE LAKE...ORD/MDW/GYY. EVEN IF THE CLOUDS/FOG TO THE NORTH DONT QUITE MAKE IT THIS FAR SOUTH...COOLER AIR MOVING INTO A VERY MOIST ENVIRONMENT COULD SUPPORT LOW CLOUD/FOG DEVELOPMENT NEAR THE LAKE SHORE ANYWAYS. CONFIDENCE IS LOW WITH REGARDS TO THE POTENTIAL BUT WILL NEED TO MONITOR THIS AND ADJUST AS NEEDED. EXPECT REDEVELOPMENT OF SHOWERS/TS LATER THIS MORNING AS ANOTHER MID LEVEL DISTURBANCE APPROACHES FROM THE WEST...WITH THIS SCATTERED DEVELOPMENT POSSIBLY CONTINUING THROUGH MID DAY. ALTHOUGH SHOULD SEE A DIMINISHING TREND INTO THE EARLY AFTERNOON...REDEVELOPMENT IN AND AROUND THE TERMINALS WILL ONCE AGAIN BE POSSIBLE LATE THIS AFTERNOON THROUGH THE EARLY EVENING. MORE WIDESPREAD SHOWERS/THUNDERSTORMS ARE EXPECTED TO MOVE ACROSS THE TERMINALS LATE THIS EVENING AND OVERNIGHT BEFORE EXITING EARLY WEDNESDAY MORNING. THE WIND FORECAST IS RATHER COMPLEX AS A WEAK GRADIENT WITH SEVERAL BOUNDARIES MOVING ACROSS THE AREA ARE IN PLACE. WITH THESE FEATURES IN PLACE...WIND DIRECTION AND SPEED WILL LIKELY RANGE SUBSTANTIALLY FROM TERMINAL TO THE OTHER. LIGHT AND VARIABLE WINDS FOR ALL OF THE TERMINALS EARLY THIS MORNING WILL PICK UP LATER THIS MORNING WITH RFD THE ONLY SITE OBSERVING A MORE SOUTHERLY DIRECTION EARLY ON. THE OTHER SITES SHOULD HOLD ONTO A NORTHEAST DIRECTION LATER THIS MORNING...LIGHT AT FIRST BUT PICKING UP IN SPEEDS. THEN AS THE GRADIENT TIGHTENS OUT AHEAD OF AN APPROACHING SYSTEM...DO EXPECT A TRANSITION TO MORE OF A SOUTHERLY DIRECTION TO OCCUR LATER THIS AFTERNOON AND THEN CONTINUE INTO THE EVENING HOURS. RODRIGUEZ //ORD AND MDW CONFIDENCE...UPDATED 09Z... * MEDIUM CONFIDENCE WITH FOG/REDUCED VIS. * LOW MEDIUM CONFIDENCE WITH SHOWERS/TS LATER THIS MORNING. * MEDIUM CONFIDENCE WITH SHOWERS/TS THIS AFTERNOON. * MEDIUM CONFIDENCE WITH SHOWERS/TS LATER THIS EVENING/OVERNIGHT. * LOW/MEDIUM CONFIDENCE ON WIND SPEED/DIRECTION. RODRIGUEZ //OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z... * WEDNESDAY...CHANCE OF TSRA...MAINLY IN THE MORNING. * THURSDAY THROUGH SUNDAY...DRY/VFR. && .MARINE... 312 PM CDT A WEAK LOW IS OVER SOUTHERN WISCONSIN AND IT WILL MOVE OVER THE LAKE TONIGHT REACHING THE EASTERN GREAT LAKES BY MORNING BEFORE DISSIPATING. WINDS WILL TURN NORTHEAST AND DIMINISH TO 10 KT OR LESS BEHIND THE LOW. A LOW FORMS OVER THE CENTRAL PLAINS TONIGHT AND WINDS VEER TO S TO SE AHEAD OF IT TOMORROW. S TO SW WINDS INCREASE TO 20 KT TUESDAY NIGHT AND THEN BECOME W TO NW BEHIND THE LOW WEDNESDAY MORNING. A HIGH FORMS OVER THE PLAINS WEDNESDAY AND THEN MOVES OVER THE LAKE THURSDAY. WINDS BECOME LIGHT UNDER THE HIGH AND THEN TURN S TO SE ON THE BACKSIDE OF THE HIGH FRIDAY NIGHT. WHILE THE CENTER OF THE HIGH SHIFTS OVER NEW ENGLAND SATURDAY...THE LAKE WILL STILL HAVE S TO SE FLOW THROUGH THE END OF THE WEEKEND. JEE && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...DENSE FOG ADVISORY...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565- LMZ567-LMZ669-LMZ671-LMZ673-LMZ868-LMZ870-LMZ872-LMZ874 UNTIL 3 PM TUESDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
418 AM CDT TUE JUL 9 2013 .DISCUSSION... 340 AM CDT SEVERE WEATHER AND HEAVY RAIN POTENTIAL THROUGH TONIGHT WAS WHAT MUCH OF THE ANALYSIS TIME WAS SPENT ON THIS MORNING. WHAT MAINLY WAS TRYING TO DO WAS LOCK DOWN A TIMING FOR AN IMPROVED SEVERE WEATHER THREAT /MID-AFTERNOON THROUGH EARLY OVERNIGHT THOUGH AIR MASS CAN ALLOW FOR ISOLATED SEVERE ANYTIME/...AND WHAT MAIN THREATS WOULD BE /WIND AND HEAVY RAIN/. OVERALL NO MAJOR CHANGES MADE TO THE FORECAST...JUST INCREASING POPS IN THOSE MOST FAVORED TIMES...RE-ORIENTING POPS SOME...AND REFINING RAINFALL AMOUNT FORECASTS. SYNOPSIS...A VERY SOUPY AIR MASS IS ENTRENCHED IN THE REGION THIS MORNING WITH MID 70S DEW POINTS ACROSS THE FORECAST AREA AND PWATS ON LAST EVES REGIONAL RAOBS AND EARLY MORNING OBJECTIVE ANALYSIS BEING AROUND 2 INCHES. NUMEROUS SHORT WAVE IMPULSES...MANY WITH ASSOCIATED CLUSTERS OF CONVECTION...ARE FOUND UPSTREAM ACROSS THE HIGH PLAINS AND OVER THE WESTERN CORN BELT ON GOES WATER VAPOR IMAGERY. THE PRIMARY UPPER LEVEL SHORT WAVE TROUGH WILL BE DIGGING INTO EASTERN MT SOON AFTER DAYBREAK AND WILL BE THE RESPONSIBLE PARTY FOR ENDING THIS MOIST AIR MASS...AT LEAST TEMPORARILY BY LATER WED. AT THE SURFACE A FAIRLY DIFFUSE GRADIENT EXISTS EARLY TODAY WITH A WEAK STATIONARY BOUNDARY NEAR THE STATE LINE. THE WEAK FLOW HAS ALLOWED FOR LOW CLOUDS AND FOG TO BE EXPANDING THEIR WAY SOUTHWARD DOWN LAKE MI AIDED BY AMBIENT DEW POINTS EXCEEDING THE WATER TEMPS BY SEVERAL DEGREES. THE PRIMARY SURFACE FRONT IS TAKING SHAPE ACROSS THE HIGH PLAINS AND WILL DEVELOP INTO A COOL FRONT LATER TODAY AS SURFACE CYCLOGENESIS OCCURS THROUGH NORTHERN MN INTO WESTERN ONTARIO BY THIS EVE. THIS FRONT WILL MOVE INTO THE FORECAST AREA LATE TONIGHT INTO EARLY WED MORNING. MULTIPLE ROUNDS OF CONVECTION ARE LIKELY AHEAD OF THIS. MODEL PREFERENCE...THE RAP AND HRRR GUIDANCE HAVE A GOOD REPRESENTATION OF ONGOING CONVECTION. THESE HAVE THE SUPPORT OF SEVERAL OTHER CONVECTIVE ALLOWING MODELS AND HAVE BEEN GUIDED ON THROUGH MID-AFTERNOON. AFTERWORDS HAVE LEANED TOWARD THE SLIGHTLY SLOWER 09.00 NAM THAN GFS. THIS MORNING...REMNANT MCV/SHORT WAVE ENTERING WESTERN IL EARLY THIS MORNING HAS BEGUN TO INCREASE RADAR ECHOES ACROSS CENTRAL IL AND THIS TREND IS LIKELY TO CONTINUE WITH SCATTERED CONVECTION FAVORED DUE TO MODERATE TO HIGH ELEVATED INSTABILITY. NOT A PARTICULARLY STRONG LOW-LEVEL JET OR ONE WITH HUGE MOISTURE TRANSPORT THIS MORNING...DUE TO STILL BEING A GOOD DISTANCE AHEAD OF MID-LEVEL HEIGHT FALLS. SO MORNING SCATTERED TO NUMEROUS SHOWERS/STORMS ACROSS CENTRAL IL MAY STRUGGLE TO PROGRESS NORTH/NORTHEAST AT LEAST AT ANY GOOD CLIP OF SPEED. THUS ROCKFORD TO CHICAGO HAVE POPS ONLY AT THE CHANCE LEVEL...AND MORE SO BASED ON ISOLATED CELLS DEVELOPING IN THE BROAD WAA AND HIGH PWAT REGIME. WITH SUCH HIGH PWATS AS YESTERDAY MORNING SHOWED...LOCALLY HEAVY RAINFALL WOULD BE THE PRIMARILY ASPECT TO KEEP AN EYE ON WITH THESE MORNING AND EARLY AFTERNOON STORMS. AS FOR EARLY MORNING FOG/STRATUS THAT HAS BEEN DEVELOPING IN PLACES...ONSHORE FLOW MAY FAVOR PATCHES OF THIS TO CONTINUE THROUGH MID OR EVEN LATE MORNING ACROSS NORTHEAST IL AND FAR NORTHWEST IN...STUNTING A TEMPERATURE CLIMB INITIALLY. OTHERWISE THIS LOOKS LIKE IT SHOULD BEGIN DISSIPATING/RETREATING NORTH AFTER THAT TIME. CONFIDENCE...HIGH. THIS AFTERNOON THROUGH TONIGHT...THE END OF THE RAP RUN AGREES CLOSELY WITH THE NAM IN TAKING THE SHORT WAVES AND ASSOCIATED 500 AND 700MB SPEED MAXS ACROSS THE DAKOTAS AND NORTHERN NEBRASKA EARLY THIS MORNING AND TRACKING THAT EAST INTO SOUTHERN WI AND NORTHERN IL BY MID TO LATE AFTERNOON. ON THE SYNOPTIC SCALE AT THAT TIME...THE LOW-LEVEL JET AND MOISTURE TRANSPORT WILL ALSO BE ON THE EXPANSE FROM MO INTO EASTERN IA/WESTERN IL. MIXED LAYER INSTABILITY WILL BE HIGH OVER THIS AREA INCLUDING THE WESTERN FORECAST AREA GIVEN TEMPS IN THE UPPER 80S TO LOWER 90S. WHILE SOME FORM OF MCS OR MULTIPLE CLUSTERS ARE PROBABLE TO BE MOVING EASTWARD OVER SOUTHERN WI/FAR NORTHERN IL DURING THE AFTERNOON WITH THE SHORT WAVES...DEVELOPMENT IS FAVORED TO WORK ITS WAY SOUTH AND BACK TO THE SOUTHWEST FROM THERE IN THE MOIST UNSTABLE AIR MASS DURING THE MID-AFTERNOON. DEEP LAYER SHEAR IS ANTICIPATED TO BE INCREASING TO AROUND 30-35 KT BY LATE AFTERNOON WITH ORGANIZED STORMS EXPECTED TO BE ALL WORKING THEIR WAY EASTWARD. AS THE PRIMARY UPPER TROUGH APPROACHES THIS EVENING...LARGER SCALE ASCENT AND FORCING IS LIKELY TO CONTINUE REGIONAL DEVELOPMENT OF STORMS NEAR AND AHEAD OF THE SURFACE FRONT. SO WHILE THERE LOOKS TO BE TWO PRIMARY FOCUSES FOR STORMS THIS AFTERNOON INTO TONIGHT...THERE IS NOT REALLY ANTICIPATED TO BE MUCH OF A BREAK AND THE HIGH PWAT AND UNSTABLE AIR SHOULD ALLOW FOR PLENTY OF COVERAGE. THAT COVERAGE MAY INITIALLY BE A LITTLE LIMITED DEPENDING ON DEBRIS CLOUD COVER BUT IS ANTICIPATED TO BE ITS HIGHEST LATER THIS AFTERNOON THROUGH EARLY OVERNIGHT. THE MOST FAVORED MODE FOR STORMS IS MULTICELL AND SEGMENTS CAPABLE OF SCATTERED DAMAGING WINDS...ESPECIALLY AS THE STRONGER MID-LEVEL JET OVERRIDES THE FRONT THIS EVENING INTO EARLY OVERNIGHT. SOME DEVELOPMENT THIS AFTERNOON THROUGH MID-EVE HAS THE POTENTIAL TO BE SUPERCELLULAR. THE LOW-LEVEL SHEAR IS FAIRLY ANEMIC MUCH OF THIS AFTERNOON /AOB 10 KT/ BUT QUICKLY INCREASES LATE INTO EARLY THIS EVE DUE TO THE DEEPENING LOW AND INCREASING LLJ. THIS WILL HELP FAVOR COLD POOL SUSTAINABILITY AND DOES PRESENT AT LEAST SOME TORNADO THREAT...ALTHOUGH IT LOOKS LIKE SURFACE WINDS MAY BE BACKED MORE TO THE WEST OF THE FORECAST AREA IMMEDIATELY AHEAD OF A SUBTLE SECONDARY SURFACE LOW MOVING UP THE FRONT. SO THE PRIMARY THREAT WILL REMAIN WIND AND OF COURSE HEAVY RAIN WITH EXTREMELY EFFICIENT RAIN PRODUCTION WILL OCCUR IN ANY STORMS TODAY AND TONIGHT. EVEN THOUGH FORWARD PROPAGATION OF STORMS SHOULD BE ON THE INCREASE TONIGHT...SO WILL DEEP MOISTURE REPLENISHMENT AND SIMPLY PUT THE ABSOLUTE MOISTURE IS SO HIGH IT WONT TAKE MUCH TO GET HIGH RAINFALL RATES SUCH AS WE SAW YESTERDAY MORNING. THERE WILL LIKELY BE SWATHS OF RAINFALL IN EXCESS OF ONE TO TWO INCHES ACROSS THE IMMEDIATE REGION...BUT WHERE EXACTLY THEY OCCUR IS TOO CHALLENGING TO LOCK DOWN. DEBATED ON A FLASH FLOOD WATCH BUT FEEL THE THREAT IS TOO LOCALIZED AT THIS TIME FOR A WATCH. CONFIDENCE...MEDIUM. WEDNESDAY...ONGOING SCATTERED SHOWERS AND STORMS ARE POSSIBLE ACROSS MAINLY THE SOUTHERN AND EASTERN FORECAST AREA IN THE MORNING WITH STILL AT LEAST SOME HEAVY RAIN THREAT. WARM 850-925MB AIR BEHIND THE SURFACE WIND SHIFT WILL STILL FAVORED HIGHS IN THE MID TO POSSIBLY EVEN UPPER 80S IN THE SOUTH. DRIER AIR WILL GRADUALLY FILTER IN DURING THE LATER AFTERNOON AND NIGHT PER GUIDANCE. CONFIDENCE...HIGH. THURSDAY THROUGH MONDAY...PRIMARILY DRY WEATHER IS EXPECTED OVER THE AREA ALTHOUGH THE TREND IN BOTH THE EC AND GFS THEIR LAST MULTIPLE RUNS SUPPORTS WARMER TEMPERATURES THIS WEEKEND WITH MID AND MAYBE EVEN UPPER 80S SEEN. HAVE COLLABORATED AND LEANED TOWARD THE WARMER MEX GUIDANCE. THE PATTERN STILL APPEARS BLOCKED JUST WITH THE AREA MORE UNDER THE INFLUENCE OF THE UPPER RIDGE TO THE WEST. MTF && .HYDROLOGY... 410 AM CDT THE VERY MOIST AIR MASS WILL SUPPORT EFFICIENT RAINFALL PRODUCTION FROM ANY THUNDERSTORMS TODAY AND TONIGHT. THIS MAY PRESENT FLASH FLOODING ESPECIALLY ON THE LOCAL LEVEL AS OPPOSED TO ANY WIDESPREAD THREAT. THAT AND THE FACT THERE IS NOT A GREAT SET UP FOR TRUE TRAINING STORMS IS WHY NO FLASH FLOOD WATCH AT THIS TIME. HOWEVER...IF ANY STORMS ARE IN A PARTICULARLY VULNERABLE AREA...SUCH AS A METRO OR A QUICK-RESPONDING WATERSHED...IT COULD BE TROUBLE. THESE TYPE OF HIGH RATES WERE ALREADY SEEN YESTERDAY MORNING WITH A NARROW SWATH OF ONE AND A HALF TO ESTIMATED THREE PLUS INCHES OF RAIN SEEN FROM RE-FIRING STORMS IN THE WEST CHICAGO METRO. HIGH RESOLUTION MODEL GUIDANCE INDICATES SUCH SWATHS ARE PROBABLE IN THE REGION THIS AFTERNOON INTO TONIGHT ALTHOUGH WHERE IS STILL UNCERTAIN. THE GENERAL RAINFALL FORECAST IS FOR MOST AREAS TO SEE AROUND AN INCH OR A LITTLE OVER BY WEDNESDAY MORNING. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 06Z... * FOG WITH REDUCED VIS OF 4SM-6SM DEVELOPING EARLY THIS MORNING. * SHOWERS WITH POSSIBLE TS REDEVELOPING LATER THIS MORNING AND CONTINUING THROUGH LATE MORNING. * REDEVELOPMENT OF SHOWERS/TS ONCE AGAIN LATER THIS AFTERNOON. * MORE WIDESPREAD SHOWERS/TS EXPECTED TO MOVE ACROSS THE TERMINALS LATER THIS EVENING AND OVERNIGHT. * COMPLEX WIND FORECAST WITH VARIABLE/LIGHT WINDS BECOMING NORTHEAST LATER THIS MORNING...THEN SHIFTING MORE SOUTHERLY LATER THIS AFTERNOON AND EVENING. RODRIGUEZ //DISCUSSION...UPDATED 06Z... A VERY COMPLEX FORECAST PERIOD FOR THE TERMINALS OVER THE NEXT 24 HOURS AS VARYING WEATHER CONDITIONS AT MULTIPLE TIMES COULD HAVE IMPACTS ON THE TERMINALS. IN THE NEAR TERM...THE SHOWERS/TS WHICH HAD DEVELOPED ACROSS NORTHEAST ILLINOIS AND OVER SOUTHERN LAKE MICHIGAN HAVE SINCE DIMINISHED EARLY THIS MORNING...AND THINK ANY FURTHER DEVELOPMENT SHOULD REMAIN VERY ISOLATED AND BRIEF OUTSIDE OF THE TERMINALS. WITH EXPECTED CLEARING...LIGHT WINDS AND A VERY MOIST ENVIRONMENT SHOULD SUPPORT FOG DEVELOPMENT OVER THE TERMINALS THIS MORNING WITH VIS RESTRICTION EXPECTED. OUTSIDE OF THIS DEVELOPMENT...A LIGHT NORTHERLY WIND OVER THE LAKE WITH LOW CEILINGS AND VIS FURTHER NORTH TOWARDS THE MIDDLE PART OF THE LAKE RAISES SOME CONCERNS FOR POTENTIAL LOWER CEILINGS AND FOG TO MOVE ACROSS THE TERMINALS NEAR THE LAKE...ORD/MDW/GYY. EVEN IF THE CLOUDS/FOG TO THE NORTH DONT QUITE MAKE IT THIS FAR SOUTH...COOLER AIR MOVING INTO A VERY MOIST ENVIRONMENT COULD SUPPORT LOW CLOUD/FOG DEVELOPMENT NEAR THE LAKE SHORE ANYWAYS. CONFIDENCE IS LOW WITH REGARDS TO THE POTENTIAL BUT WILL NEED TO MONITOR THIS AND ADJUST AS NEEDED. EXPECT REDEVELOPMENT OF SHOWERS/TS LATER THIS MORNING AS ANOTHER MID LEVEL DISTURBANCE APPROACHES FROM THE WEST...WITH THIS SCATTERED DEVELOPMENT POSSIBLY CONTINUING THROUGH MID DAY. ALTHOUGH SHOULD SEE A DIMINISHING TREND INTO THE EARLY AFTERNOON...REDEVELOPMENT IN AND AROUND THE TERMINALS WILL ONCE AGAIN BE POSSIBLE LATE THIS AFTERNOON THROUGH THE EARLY EVENING. MORE WIDESPREAD SHOWERS/THUNDERSTORMS ARE EXPECTED TO MOVE ACROSS THE TERMINALS LATE THIS EVENING AND OVERNIGHT BEFORE EXITING EARLY WEDNESDAY MORNING. THE WIND FORECAST IS RATHER COMPLEX AS A WEAK GRADIENT WITH SEVERAL BOUNDARIES MOVING ACROSS THE AREA ARE IN PLACE. WITH THESE FEATURES IN PLACE...WIND DIRECTION AND SPEED WILL LIKELY RANGE SUBSTANTIALLY FROM TERMINAL TO THE OTHER. LIGHT AND VARIABLE WINDS FOR ALL OF THE TERMINALS EARLY THIS MORNING WILL PICK UP LATER THIS MORNING WITH RFD THE ONLY SITE OBSERVING A MORE SOUTHERLY DIRECTION EARLY ON. THE OTHER SITES SHOULD HOLD ONTO A NORTHEAST DIRECTION LATER THIS MORNING...LIGHT AT FIRST BUT PICKING UP IN SPEEDS. THEN AS THE GRADIENT TIGHTENS OUT AHEAD OF AN APPROACHING SYSTEM...DO EXPECT A TRANSITION TO MORE OF A SOUTHERLY DIRECTION TO OCCUR LATER THIS AFTERNOON AND THEN CONTINUE INTO THE EVENING HOURS. RODRIGUEZ //ORD AND MDW CONFIDENCE...UPDATED 06Z... * MEDIUM CONFIDENCE WITH FOG/REDUCED VIS. * LOW MEDIUM CONFIDENCE WITH SHOWERS/TS LATER THIS MORNING. * MEDIUM CONFIDENCE WITH SHOWERS/TS THIS AFTERNOON. * MEDIUM CONFIDENCE WITH SHOWERS/TS LATER THIS EVENING/OVERNIGHT. * LOW/MEDIUM CONFIDENCE ON WIND SPEED/DIRECTION. RODRIGUEZ //OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z... * WEDNESDAY...CHANCE OF TSRA...MAINLY IN THE MORNING. * THURSDAY THROUGH SUNDAY...DRY/VFR. && .MARINE... 312 PM CDT A WEAK LOW IS OVER SOUTHERN WISCONSIN AND IT WILL MOVE OVER THE LAKE TONIGHT REACHING THE EASTERN GREAT LAKES BY MORNING BEFORE DISSIPATING. WINDS WILL TURN NORTHEAST AND DIMINISH TO 10 KT OR LESS BEHIND THE LOW. A LOW FORMS OVER THE CENTRAL PLAINS TONIGHT AND WINDS VEER TO S TO SE AHEAD OF IT TOMORROW. S TO SW WINDS INCREASE TO 20 KT TUESDAY NIGHT AND THEN BECOME W TO NW BEHIND THE LOW WEDNESDAY MORNING. A HIGH FORMS OVER THE PLAINS WEDNESDAY AND THEN MOVES OVER THE LAKE THURSDAY. WINDS BECOME LIGHT UNDER THE HIGH AND THEN TURN S TO SE ON THE BACKSIDE OF THE HIGH FRIDAY NIGHT. WHILE THE CENTER OF THE HIGH SHIFTS OVER NEW ENGLAND SATURDAY...THE LAKE WILL STILL HAVE S TO SE FLOW THROUGH THE END OF THE WEEKEND. JEE && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...DENSE FOG ADVISORY...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565- LMZ567-LMZ669-LMZ671-LMZ673-LMZ868-LMZ870-LMZ872-LMZ874 UNTIL 3 PM TUESDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
348 AM CDT TUE JUL 9 2013 .DISCUSSION... 340 AM CDT SEVERE WEATHER AND HEAVY RAIN POTENTIAL THROUGH TONIGHT WAS WHAT MUCH OF THE ANALYSIS TIME WAS SPENT ON THIS MORNING. WHAT MAINLY WAS TRYING TO DO WAS LOCK DOWN A TIMING FOR AN IMPROVED SEVERE WEATHER THREAT /MID-AFTERNOON THROUGH EARLY OVERNIGHT THOUGH AIR MASS CAN ALLOW FOR ISOLATED SEVERE ANYTIME/...AND WHAT MAIN THREATS WOULD BE /WIND AND HEAVY RAIN/. OVERALL NO MAJOR CHANGES MADE TO THE FORECAST...JUST INCREASING POPS IN THOSE MOST FAVORED TIMES...RE-ORIENTING POPS SOME...AND REFINING RAINFALL AMOUNT FORECASTS. SYNOPSIS...A VERY SOUPY AIR MASS IS ENTRENCHED IN THE REGION THIS MORNING WITH MID 70S DEW POINTS ACROSS THE FORECAST AREA AND PWATS ON LAST EVES REGIONAL RAOBS AND EARLY MORNING OBJECTIVE ANALYSIS BEING AROUND 2 INCHES. NUMEROUS SHORT WAVE IMPULSES...MANY WITH ASSOCIATED CLUSTERS OF CONVECTION...ARE FOUND UPSTREAM ACROSS THE HIGH PLAINS AND OVER THE WESTERN CORN BELT ON GOES WATER VAPOR IMAGERY. THE PRIMARY UPPER LEVEL SHORT WAVE TROUGH WILL BE DIGGING INTO EASTERN MT SOON AFTER DAYBREAK AND WILL BE THE RESPONSIBLE PARTY FOR ENDING THIS MOIST AIR MASS...AT LEAST TEMPORARILY BY LATER WED. AT THE SURFACE A FAIRLY DIFFUSE GRADIENT EXISTS EARLY TODAY WITH A WEAK STATIONARY BOUNDARY NEAR THE STATE LINE. THE WEAK FLOW HAS ALLOWED FOR LOW CLOUDS AND FOG TO BE EXPANDING THEIR WAY SOUTHWARD DOWN LAKE MI AIDED BY AMBIENT DEW POINTS EXCEEDING THE WATER TEMPS BY SEVERAL DEGREES. THE PRIMARY SURFACE FRONT IS TAKING SHAPE ACROSS THE HIGH PLAINS AND WILL DEVELOP INTO A COOL FRONT LATER TODAY AS SURFACE CYCLOGENESIS OCCURS THROUGH NORTHERN MN INTO WESTERN ONTARIO BY THIS EVE. THIS FRONT WILL MOVE INTO THE FORECAST AREA LATE TONIGHT INTO EARLY WED MORNING. MULTIPLE ROUNDS OF CONVECTION ARE LIKELY AHEAD OF THIS. MODEL PREFERENCE...THE RAP AND HRRR GUIDANCE HAVE A GOOD REPRESENTATION OF ONGOING CONVECTION. THESE HAVE THE SUPPORT OF SEVERAL OTHER CONVECTIVE ALLOWING MODELS AND HAVE BEEN GUIDED ON THROUGH MID-AFTERNOON. AFTERWORDS HAVE LEANED TOWARD THE SLIGHTLY SLOWER 09.00 NAM THAN GFS. THIS MORNING...REMNANT MCV/SHORT WAVE ENTERING WESTERN IL EARLY THIS MORNING HAS BEGUN TO INCREASE RADAR ECHOES ACROSS CENTRAL IL AND THIS TREND IS LIKELY TO CONTINUE WITH SCATTERED CONVECTION FAVORED DUE TO MODERATE TO HIGH ELEVATED INSTABILITY. NOT A PARTICULARLY STRONG LOW-LEVEL JET OR ONE WITH HUGE MOISTURE TRANSPORT THIS MORNING...DUE TO STILL BEING A GOOD DISTANCE AHEAD OF MID-LEVEL HEIGHT FALLS. SO MORNING SCATTERED TO NUMEROUS SHOWERS/STORMS ACROSS CENTRAL IL MAY STRUGGLE TO PROGRESS NORTH/NORTHEAST AT LEAST AT ANY GOOD CLIP OF SPEED. THUS ROCKFORD TO CHICAGO HAVE POPS ONLY AT THE CHANCE LEVEL...AND MORE SO BASED ON ISOLATED CELLS DEVELOPING IN THE BROAD WAA AND HIGH PWAT REGIME. WITH SUCH HIGH PWATS AS YESTERDAY MORNING SHOWED...LOCALLY HEAVY RAINFALL WOULD BE THE PRIMARILY ASPECT TO KEEP AN EYE ON WITH THESE MORNING AND EARLY AFTERNOON STORMS. AS FOR EARLY MORNING FOG/STRATUS THAT HAS BEEN DEVELOPING IN PLACES...ONSHORE FLOW MAY FAVOR PATCHES OF THIS TO CONTINUE THROUGH MID OR EVEN LATE MORNING ACROSS NORTHEAST IL AND FAR NORTHWEST IN...STUNTING A TEMPERATURE CLIMB INITIALLY. OTHERWISE THIS LOOKS LIKE IT SHOULD BEGIN DISSIPATING/RETREATING NORTH AFTER THAT TIME. CONFIDENCE...HIGH. THIS AFTERNOON THROUGH TONIGHT...THE END OF THE RAP RUN AGREES CLOSELY WITH THE NAM IN TAKING THE SHORT WAVES AND ASSOCIATED 500 AND 700MB SPEED MAXS ACROSS THE DAKOTAS AND NORTHERN NEBRASKA EARLY THIS MORNING AND TRACKING THAT EAST INTO SOUTHERN WI AND NORTHERN IL BY MID TO LATE AFTERNOON. ON THE SYNOPTIC SCALE AT THAT TIME...THE LOW-LEVEL JET AND MOISTURE TRANSPORT WILL ALSO BE ON THE EXPANSE FROM MO INTO EASTERN IA/WESTERN IL. MIXED LAYER INSTABILITY WILL BE HIGH OVER THIS AREA INCLUDING THE WESTERN FORECAST AREA GIVEN TEMPS IN THE UPPER 80S TO LOWER 90S. WHILE SOME FORM OF MCS OR MULTIPLE CLUSTERS ARE PROBABLE TO BE MOVING EASTWARD OVER SOUTHERN WI/FAR NORTHERN IL DURING THE AFTERNOON WITH THE SHORT WAVES...DEVELOPMENT IS FAVORED TO WORK ITS WAY SOUTH AND BACK TO THE SOUTHWEST FROM THERE IN THE MOIST UNSTABLE AIR MASS DURING THE MID-AFTERNOON. DEEP LAYER SHEAR IS ANTICIPATED TO BE INCREASING TO AROUND 30-35 KT BY LATE AFTERNOON WITH ORGANIZED STORMS EXPECTED TO BE ALL WORKING THEIR WAY EASTWARD. AS THE PRIMARY UPPER TROUGH APPROACHES THIS EVENING...LARGER SCALE ASCENT AND FORCING IS LIKELY TO CONTINUE REGIONAL DEVELOPMENT OF STORMS NEAR AND AHEAD OF THE SURFACE FRONT. SO WHILE THERE LOOKS TO BE TWO PRIMARY FOCUSES FOR STORMS THIS AFTERNOON INTO TONIGHT...THERE IS NOT REALLY ANTICIPATED TO BE MUCH OF A BREAK AND THE HIGH PWAT AND UNSTABLE AIR SHOULD ALLOW FOR PLENTY OF COVERAGE. THAT COVERAGE MAY INITIALLY BE A LITTLE LIMITED DEPENDING ON DEBRIS CLOUD COVER BUT IS ANTICIPATED TO BE ITS HIGHEST LATER THIS AFTERNOON THROUGH EARLY OVERNIGHT. THE MOST FAVORED MODE FOR STORMS IS MULTICELL AND SEGMENTS CAPABLE OF SCATTERED DAMAGING WINDS...ESPECIALLY AS THE STRONGER MID-LEVEL JET OVERRIDES THE FRONT THIS EVENING INTO EARLY OVERNIGHT. SOME DEVELOPMENT THIS AFTERNOON THROUGH MID-EVE HAS THE POTENTIAL TO BE SUPERCELLULAR. THE LOW-LEVEL SHEAR IS FAIRLY ANEMIC MUCH OF THIS AFTERNOON /AOB 10 KT/ BUT QUICKLY INCREASES LATE INTO EARLY THIS EVE DUE TO THE DEEPENING LOW AND INCREASING LLJ. THIS WILL HELP FAVOR COLD POOL SUSTAINABILITY AND DOES PRESENT AT LEAST SOME TORNADO THREAT...ALTHOUGH IT LOOKS LIKE SURFACE WINDS MAY BE BACKED MORE TO THE WEST OF THE FORECAST AREA IMMEDIATELY AHEAD OF A SUBTLE SECONDARY SURFACE LOW MOVING UP THE FRONT. SO THE PRIMARY THREAT WILL REMAIN WIND AND OF COURSE HEAVY RAIN WITH EXTREMELY EFFICIENT RAIN PRODUCTION WILL OCCUR IN ANY STORMS TODAY AND TONIGHT. EVEN THOUGH FORWARD PROPAGATION OF STORMS SHOULD BE ON THE INCREASE TONIGHT...SO WILL DEEP MOISTURE REPLENISHMENT AND SIMPLY PUT THE ABSOLUTE MOISTURE IS SO HIGH IT WONT TAKE MUCH TO GET HIGH RAINFALL RATES SUCH AS WE SAW YESTERDAY MORNING. THERE WILL LIKELY BE SWATHS OF RAINFALL IN EXCESS OF ONE TO TWO INCHES ACROSS THE IMMEDIATE REGION...BUT WHERE EXACTLY THEY OCCUR IS TOO CHALLENGING TO LOCK DOWN. DEBATED ON A FLASH FLOOD WATCH BUT FEEL THE THREAT IS TOO LOCALIZED AT THIS TIME FOR A WATCH. CONFIDENCE...MEDIUM. THE REMAINDER OF THE DISCUSSION WILL BE ISSUED SHORTLY. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 06Z... * FOG WITH REDUCED VIS OF 4SM-6SM DEVELOPING EARLY THIS MORNING. * SHOWERS WITH POSSIBLE TS REDEVELOPING LATER THIS MORNING AND CONTINUING THROUGH LATE MORNING. * REDEVELOPMENT OF SHOWERS/TS ONCE AGAIN LATER THIS AFTERNOON. * MORE WIDESPREAD SHOWERS/TS EXPECTED TO MOVE ACROSS THE TERMINALS LATER THIS EVENING AND OVERNIGHT. * COMPLEX WIND FORECAST WITH VARIABLE/LIGHT WINDS BECOMING NORTHEAST LATER THIS MORNING...THEN SHIFTING MORE SOUTHERLY LATER THIS AFTERNOON AND EVENING. RODRIGUEZ //DISCUSSION...UPDATED 06Z... A VERY COMPLEX FORECAST PERIOD FOR THE TERMINALS OVER THE NEXT 24 HOURS AS VARYING WEATHER CONDITIONS AT MULTIPLE TIMES COULD HAVE IMPACTS ON THE TERMINALS. IN THE NEAR TERM...THE SHOWERS/TS WHICH HAD DEVELOPED ACROSS NORTHEAST ILLINOIS AND OVER SOUTHERN LAKE MICHIGAN HAVE SINCE DIMINISHED EARLY THIS MORNING...AND THINK ANY FURTHER DEVELOPMENT SHOULD REMAIN VERY ISOLATED AND BRIEF OUTSIDE OF THE TERMINALS. WITH EXPECTED CLEARING...LIGHT WINDS AND A VERY MOIST ENVIRONMENT SHOULD SUPPORT FOG DEVELOPMENT OVER THE TERMINALS THIS MORNING WITH VIS RESTRICTION EXPECTED. OUTSIDE OF THIS DEVELOPMENT...A LIGHT NORTHERLY WIND OVER THE LAKE WITH LOW CEILINGS AND VIS FURTHER NORTH TOWARDS THE MIDDLE PART OF THE LAKE RAISES SOME CONCERNS FOR POTENTIAL LOWER CEILINGS AND FOG TO MOVE ACROSS THE TERMINALS NEAR THE LAKE...ORD/MDW/GYY. EVEN IF THE CLOUDS/FOG TO THE NORTH DONT QUITE MAKE IT THIS FAR SOUTH...COOLER AIR MOVING INTO A VERY MOIST ENVIRONMENT COULD SUPPORT LOW CLOUD/FOG DEVELOPMENT NEAR THE LAKE SHORE ANYWAYS. CONFIDENCE IS LOW WITH REGARDS TO THE POTENTIAL BUT WILL NEED TO MONITOR THIS AND ADJUST AS NEEDED. EXPECT REDEVELOPMENT OF SHOWERS/TS LATER THIS MORNING AS ANOTHER MID LEVEL DISTURBANCE APPROACHES FROM THE WEST...WITH THIS SCATTERED DEVELOPMENT POSSIBLY CONTINUING THROUGH MID DAY. ALTHOUGH SHOULD SEE A DIMINISHING TREND INTO THE EARLY AFTERNOON...REDEVELOPMENT IN AND AROUND THE TERMINALS WILL ONCE AGAIN BE POSSIBLE LATE THIS AFTERNOON THROUGH THE EARLY EVENING. MORE WIDESPREAD SHOWERS/THUNDERSTORMS ARE EXPECTED TO MOVE ACROSS THE TERMINALS LATE THIS EVENING AND OVERNIGHT BEFORE EXITING EARLY WEDNESDAY MORNING. THE WIND FORECAST IS RATHER COMPLEX AS A WEAK GRADIENT WITH SEVERAL BOUNDARIES MOVING ACROSS THE AREA ARE IN PLACE. WITH THESE FEATURES IN PLACE...WIND DIRECTION AND SPEED WILL LIKELY RANGE SUBSTANTIALLY FROM TERMINAL TO THE OTHER. LIGHT AND VARIABLE WINDS FOR ALL OF THE TERMINALS EARLY THIS MORNING WILL PICK UP LATER THIS MORNING WITH RFD THE ONLY SITE OBSERVING A MORE SOUTHERLY DIRECTION EARLY ON. THE OTHER SITES SHOULD HOLD ONTO A NORTHEAST DIRECTION LATER THIS MORNING...LIGHT AT FIRST BUT PICKING UP IN SPEEDS. THEN AS THE GRADIENT TIGHTENS OUT AHEAD OF AN APPROACHING SYSTEM...DO EXPECT A TRANSITION TO MORE OF A SOUTHERLY DIRECTION TO OCCUR LATER THIS AFTERNOON AND THEN CONTINUE INTO THE EVENING HOURS. RODRIGUEZ //ORD AND MDW CONFIDENCE...UPDATED 06Z... * MEDIUM CONFIDENCE WITH FOG/REDUCED VIS. * LOW MEDIUM CONFIDENCE WITH SHOWERS/TS LATER THIS MORNING. * MEDIUM CONFIDENCE WITH SHOWERS/TS THIS AFTERNOON. * MEDIUM CONFIDENCE WITH SHOWERS/TS LATER THIS EVENING/OVERNIGHT. * LOW/MEDIUM CONFIDENCE ON WIND SPEED/DIRECTION. RODRIGUEZ //OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z... * WEDNESDAY...CHANCE OF TSRA...MAINLY IN THE MORNING. * THURSDAY THROUGH SUNDAY...DRY/VFR. && .MARINE... 312 PM CDT A WEAK LOW IS OVER SOUTHERN WISCONSIN AND IT WILL MOVE OVER THE LAKE TONIGHT REACHING THE EASTERN GREAT LAKES BY MORNING BEFORE DISSIPATING. WINDS WILL TURN NORTHEAST AND DIMINISH TO 10 KT OR LESS BEHIND THE LOW. A LOW FORMS OVER THE CENTRAL PLAINS TONIGHT AND WINDS VEER TO S TO SE AHEAD OF IT TOMORROW. S TO SW WINDS INCREASE TO 20 KT TUESDAY NIGHT AND THEN BECOME W TO NW BEHIND THE LOW WEDNESDAY MORNING. A HIGH FORMS OVER THE PLAINS WEDNESDAY AND THEN MOVES OVER THE LAKE THURSDAY. WINDS BECOME LIGHT UNDER THE HIGH AND THEN TURN S TO SE ON THE BACKSIDE OF THE HIGH FRIDAY NIGHT. WHILE THE CENTER OF THE HIGH SHIFTS OVER NEW ENGLAND SATURDAY...THE LAKE WILL STILL HAVE S TO SE FLOW THROUGH THE END OF THE WEEKEND. JEE && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
148 AM EDT TUE JUL 9 2013 .SYNOPSIS... ISSUED AT 651 PM EDT MON JUL 8 2013 SHOWER AND THUNDERSTORM COVERAGE WILL INCREASE THROUGH THE EVENING AND INTO THE OVERNIGHT HOURS TONIGHT WITH LOW TEMPERATURES IN THE LOW 70S. THERE IS A CHANCE OF SHOWERS AND THUNDERSTORMS AGAIN ON TUESDAY WITH HIGH TEMPERATURES IN THE UPPER 80S. A FEW OF THE THUNDERSTORMS COULD BE STRONG TO SEVERE. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 314 PM EDT MON JUL 8 2013 COMPLICATED FCST PERIOD WRT CONVECTIVE POTENTIAL THIS EVENING AND AGAIN ON TUESDAY. AREA OF SHOWERS AND THUNDERSTORMS THAT DEVELOPED THIS MORNING ACROSS NE IL HAVE ADVECTED INTO THE NW CWA THIS AFTERNOON. THIS AREA OF SHOWERS APPEARS TO BE IN A DECAYING STATE...AND HAS WORKED OVER THE ENVIRONMENT ACROSS MUCH OF THE AREA. THE DEGREE OF RECOVERY LATE THIS AFTERNOON AND EARLY THIS EVENING WILL BE CRITICAL TO ANY CONVECTIVE POTENTIAL GOING FORWARD INTO THE OVERNIGHT. HI RES MODELS HAVE DONE A POOR JOB WITH THE CONVECTIVE EVOLUTION OVER THE PAST 6 HOURS. HRRR AND 12Z SPC 4KM RUNS HAVE INDICATED A W-E ORIENTED LINE OF CONVECTION DEVELOPING ACROSS THE LOWER GREAT LAKES REGION AND SINKING SOUTHWARD ACROSS THE AREA...COINCIDENT WITH SHORTWAVE ENERGY ADVECTING SOUTHEAST ACROSS THE LOWER GREAT LAKES PER W/V. THE COVERAGE AND EXTENT OF THIS POTENTIAL CONVECTION WILL BE HIGHLY DEPENDENT ON ATMOSPHERIC RECOVERY. RECENT RAP13 RUNS DO INDICATED A STRONG LOW LVL THETA E POOLING ACROSS NRN IL...ADVECTING INTO NRN IN THROUGH 00Z. THIS OPTIMISTIC SCENARIO WOULD ALLOW MLCAPES TO RECOVER TO 1000-2000 J/KG. MODEST 0-6 KM BULK SHEAR VALUES OF 25-30 KTS...AND 850-500 MB LAPSE RATES OF 5.5-6 C/KM WILL KEEP SEVERE POTENTIAL LOW TO MARGINAL AT THIS POINT....HOWEVER AN ISOLATED STORM PRODUCING STRONG TO SEVERE WIND GUSTS IS POSSIBLE. GIVEN ALL OF THESE FACTORS...DECIDED TO LEAVE POPS IN THE SCATTERED CATEGORY TONIGHT...WITH THE BEST POTENTIAL FOR CONVECTION BETWEEN 22Z AND 04Z. CONVECTIVE OUTFLOW SHOULD PUSH PRECIP POTENTIAL SOUTHWARD THROUGH THE OVERNIGHT HOURS...AND HAVE CONFINED SLIGHT CHANCE POPS TO THE SOUTH. WARM AND MUGGY CONDITIONS ARE EXPECTED AGAIN ON TUESDAY WITH HIGHS TOPPING OUT IN THE MID TO UPPER 80S...WITH HEAT INDICES IN THE LOW TO MID 90S. REMNANT CONVECTIVE BOUNDARY MAY BE A FOCUS FOR SHOWER AND THUNDERSTORM ACTIVITY TOMORROW WITH A JUICED ENVIRONMENT. UPSTREAM SHORTWAVE EXPECTED TO ADVECT INTO THE REGION LATE TUESDAY AFTERNOON...WHICH WILL PROVIDE MORE SUPPORT FOR CONVECTION. GIVEN UNCERTAINTY WITH EVOLUTION OF CONVECTION THIS EVENING...AND RESULTING BOUNDARY LOCATION...AS WELL AS UNCERTAINTY WITH THE EVOLUTION OF CONVECTIVELY INDUCED SHORTWAVE...HAVE OPTED TO KEEP POPS IN THE CHANCE RANGE...WITH THE HIGHEST IN THE AFTERNOON. POTENTIAL FOR SEVERE WIND GUSTS TOMORROW DOES EXIST GIVEN HIGHLY UNSTABLE ENVIRONMENT...BUT MODEST BULK SHEAR VALUES OF 25-30 KTS MAY BE A LIMITING FACTOR FOR STORM ORGANIZATION. && .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 314 PM EDT MON JUL 8 2013 SHARPENING MID LVL TROUGH SWEEPING THROUGH SRN CANADA SHRT TERM WILL PROPEL A VIGOROUS CDFNT THROUGH CWA ON WED. IN LIGHT OF DISPARATE MODEL GUIDANCE WILL GENERALLY RELY ON HIGHRES CONSENSUS OF FASTER FROPA ESP WITHIN GUISE OF TUE NIGHT CONVN/MCS AND LIKELY OUTFLW REMNANT COMPOSITING MORE EFFECTIVE DY3 FORCING MECHANISM SWD TWD THE OH VALLEY. AS SUCH HAVE SHARPLY CURTAILED POPS ON WED. AFT THAT...HIGH PRES TO RIDGE SWD ACRS THE LAKES AS MID LVL TROUGH AMPLIFIES THROUGH NEW ENGLAND BRINGING SEASONABLE TEMPS TO THE REGION AND DRY WX. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 140 AM EDT TUE JUL 9 2013 POINT/AIRFIELD CHANCES FOR CONVECTION EXIST...THOUGH TOO LOW TO WARRANT ANY INCLUSION ATTM. BEST FOCUS ASSOCD WITH APPROACH OF NRN STREAM WAVE LATE IN FORECAST PD AND ADDRESS WITH TEMPO TSRA AT KSBN...HEAVY RAFL POTENTIAL GIVEN WARM/MOIST TROPOSPHERE DEPTH SUGGESTS AT LEAST BRIEF IFR VSBYS REDUCTIONS WITHIN/NEAR CONVECTIVE CELL CORES. TIMING APPEARS JUST OUTSIDE OF CURRENT FORECAST WINDOW AT KFWA...TO BE INCLUDED WITH 12 UTC ITERATION. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ SYNOPSIS...BENTLEY SHORT TERM...NG LONG TERM...T AVIATION...MURPHY VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV WWW.TWITTER.COM/NWSIWX WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
401 AM CDT TUE JUL 9 2013 .SYNOPSIS... ISSUED AT 330 AM CDT TUE JUL 9 2013 06Z MSAS SFC ANALYSIS SUPPORTIVE OF WEAK LOW OVER CENTRAL SD WITH STATIONARY FRONT EXTENDING SEWD FROM THE LOW AND BISECTING EASTERN IA AND NORTHWEST IL. MOISTURE IS POOLING ALONG THE FRONT WITH DEWPTS OF 70-75F. 00Z KDVN RAOB SHOWS DEEP MOISTURE WITH PRECIPITABLE WATER VALUES OF NEARLY 2 INCHES... WHICH IS AROUND 160 PERCENT OF NORMAL AND NEARLY 2 STANDARD DEVIATIONS ABOVE THE MEAN. CONVECTIVELY ENHANCED VORT MAX IS TRACKING THROUGH EASTERN NE ATTM WITH RADARS SHOWING SHOWERS AND STORMS AHEAD OF THIS FEATURE INTO WESTERN IA. ADDITIONAL COMPLEX OF STORMS WAS OVER THE DAKOTAS AHEAD OF COLD FRONT AND SHORTWAVE MOVING EAST THROUGH FAR SOUTHERN ALBERTA PROVINCE AND NORTHERN MT. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 330 AM CDT TUE JUL 9 2013 SUGGESTIONS OF 2 MAIN ROUNDS OF STORMS THROUGH THE PERIOD. AS CONVECTIVELY ENHANCED VORT MAX MOVES EAST FROM NE ANTICIPATE SHOWERS AND STORMS TRACKING AHEAD OF THIS FEATURE TO MOVE ACROSS THE REGION BY MID AM THROUGH EARLY AFTN. PRIOR TO THE ARRIVAL OF THESE STORMS COULD SEE ADDITIONAL DEVELOPMENT PRIOR TO MID AM OVER THE AREA WITH WARM ADVECTION WING. POTENTIAL FOR SOME STRENGTHENING OF MID LEVEL WINDS AND INTENSIFICATION OF STORMS BY LATE AM AND AFTN FOR RISK OF FEW STRONG TO ISOLD SEVERE STORMS WITH MOST RECENT RUNS OF HRRR 2-5KM UPDRAFT HELICITY AND 3 KM VELOCITY CONTINUING TO SUGGEST THIS RISK NEAR AND ESPECIALLY NORTH OF I-80. MAY SEE BREAK IN ACTION OR RELATIVE LULL IN ACTIVITY BY MID-LATE AFTN WITH FOCUS SHIFTING BACK NORTHWEST FOR DEVELOPMENT AHEAD OF COLD FRONT. LIKELY TO SEE ANOTHER ROUND OF STORMS MOVE THROUGH THIS EVENING INTO OVERNIGHT AHEAD OF COLD FRONT. STRENGTHENING 40-60 KT MID LEVEL SPEED MAX SPREADING BEHIND FRONT COUPLED WITH VERY UNSTABLE ENVIRONMENT WILL SUPPORT RISK OF SEVERE STORMS WITH POTENTIAL FOR UPSCALE GROWTH TO LINEAR MCS WITH MAINLY DAMAGING WIND THREAT. HEAVY RAIN WILL BE A CONCERN AS WELL GIVEN THE DEEP ALMOST TROPICAL MOISTURE IN PLACE. STORMS SHOULD BE MOVING ALONG MORE THAN WE/VE SEEN OF LATE BUT WILL BE VERY EFFICIENT RAIN PRODUCERS WITH RATES LIKELY 1-2"/HR. THUS... CANT RULE OUT SOME LOCALIZED FLASH FLOODING AND WILL HAVE TO BE ESPECIALLY WATCHFULL OVER PORTIONS OF DELAWARE AND DUBUQUE COUNTIES WHICH HAVE SEEN 2-5 INCHES PAST 24-36 HRS. EXPECT PCPN SHOULD BE DIMINISHING FROM NW TO SE OVRNGT WITH PASSAGE OF COLD FRONT. HIGHS TDY TRICKY WITH CLOUDS AND PCPN BUT OVERALL SHOULD RANGE FROM MID 80S TO THE LOWER 90S. SOME MIXING OUT OF DEWPTS MAY OCCUR BUT AT LEAST UPPER 60S TO LOWER 70S EXPECTED ON DEWPTS... WHICH COMBINED WITH TEMPS WILL MAKE FOR HEAT INDICES MAINLY IN THE MID TO UPPER 90S. COOLER AND DRIER AIR LAGS BEHIND FRONT TNGT... THUS LOWS ONLY DROP INTO THE UPPER 60S TO LOWER 70S. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 330 AM CDT TUE JUL 9 2013 WEDNESDAY AND THURSDAY...AS L/W TROF CONTINUES TO DEEPEN AND ESTABLISH ACRS THE GRT LKS...SEASONABLY STRONG LLVL HIGH PRESSURE WILL LOOK TO DUMP DOWN THE NORTHERN PLAINS AND MO RVR VALLEY ON WED. A FEW POST-FRONTAL SHOWERS AND STORMS MAY BE OCCURRING ACRS THE FAR EASTERN/SOUTHERN CWA WED MORNING BUT BULK OF THE ACTIVITY SHOULD BE GONE BY 15Z. VEERING AND INCREASING BOUNDARY LAYER FLOW AS WELL AS INCOMING SUBSIDENCE SHOULD CLEAR THINGS OUT ON WED...BUT SOME LAG IN CAA TO ALLOW TEMPS TO WARM INTO THE LOW TO MID 80S EVEN POST- FRONTALLY. A RATHER BREEZY NORTHWEST TO NORTH WIND OF 15-20 MPH. CLEAR SKIES AND WIND DROP OFF WED NIGHT TO ALLOW SOME AREA TEMPS TO DROP OFF INTO THE 50S. LLVL HIGH PRESSURE CONTINUING TO MIGRATE EASTWARD ACRS THE REGION TO MAKE FOR A CHAMBER OF COMMERCE DAY THU WITH HIGHS IN THE UPPER 70S TO LOWER 80S...SUNSHINE AND LOWER HUMIDITY. THU NIGHT SEASONABLY COOL AGAIN WITH LOWS IN THE 50S AND LOW 60S. FRIDAY THROUGH NEXT MONDAY...TRENDS OF THE LATEST RUN 00Z MEDIUM RANGE SOLUTIONS AND ENSEMBLES SUGGEST SOME DIGGING TROFFINESS IN THE PACIFIC NORTHWEST/WESTERN CANADA TO TRANSLATE INTO PUMPED UP UPPER RIDGING ACRS THE MID CONUS FRI INTO SAT. THUS WHILE THERMAL DOME INTENSIFIES ACRS THE GRT BSN INTO THE SOUTHWESTERN PLAINS...MCS TRACK/RING OF FIRE PATTERN TO ESTABLISH IN NORMAL DEEP SUMMER LOCATION OF NORTHWESTERN HIGH PLAINS...UPPER MS RVR VALLEY...SOUTHERN CANADA AND INTO THE GRT LKS. LATEST INDICATIONS SUGGEST A LESSENING CHANCE FOR SOME OF THIS MCS ACTIVITY TO SPILL DOWN ACRS THE NORTHERN CWA EITHER FRI NIGHT OR SAT NIGHT WHILE TEMPERATURES START TO REBOUND BACK TO NORMAL OR EVEN WARMER. BY SUNDAY...WESTERLIES FIRMLY ESTABLISH ACRS THE U.S.-CANADIAN BORDER REGION WITH UPPER RIDGING DOMINATING ACRS THE SOUTHERN 2/3S OF THE CONUS. LONGER RANGE THERMAL PROFILES SUGGEST ENOUGH AIRMASS MODIFICATION TO DRIVE SUNDAY HIGHS UP INTO AT LEAST THE LOWER 90S ALONG WITH INCREASING SFC DPTS/HUMIDITY. PASSING WAVE IN THIS PROGRESSIVE FLOW MAY TRY TO SHUNT DOWN A WEAKENING SFC BOUNDARY DOWN TOWARD OR ACRS THE CWA LATER SUNDAY NIGHT OR MONDAY AND GET SLOWED AS IT ALIGNS PARALLEL TO MEAN STEERING FLOW. THUS THIS WINDOW MAY BE THE NEXT REAL CHANCE FOR SOME PRECIP IN THE AREA AFTER TODAY/TONIGHT. LONGER RANGE SIGNALS ON THE LATEST RUNS ESPECIALLY THE NEW 00Z ECMWF SUGGESTS THAT THIS BROAD UPPER RIDGING PATTERN TO CONTINUE TO REIGN ACRS MUCH OF THE CONUS WELL INTO MID NEXT WEEK...WHILE THE TROPICS CONTINUE TO GET INTERESTING. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1135 PM CDT MON JUL 8 2013 LIGHT WINDS AND SUMMER HUMIDITY WILL LIKELY LEAD TO FOG DEVELOPMENT TONIGHT AND FOR NOW WILL ANTICIPATE MID LEVEL CLOUD COVER TO PREVENT VISIBILITIES FROM DROPPING ANY LOWER THAN 4 OR 5 MILES LATE TONIGHT. THERE REMAINS A CHANCE FOR ISOLATED TO WIDELY SCATTERED THUNDERSTORMS TONIGHT THROUGH TUESDAY NIGHT. THE BEST CHANCES WILL BE CENTERED ALONG AND AHEAD OF A COLD FRONT THAT WILL DROP THROUGH THE AREA TUESDAY EVENING. AHEAD OF THIS...HAVE GONE WITH LOW CONFIDENCE PROB30 OR VCTS WORDING TO COVER THE POTENTIAL. WINDS WILL BE LIGHT AND PRIMARILY FROM THE SOUTH TO SOUTHWEST THROUGHOUT. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ SYNOPSIS...05 SHORT TERM...05 LONG TERM...12 AVIATION...SHEETS
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
359 AM EDT TUE JUL 9 2013 .SYNOPSIS... A SERIES OF UPPER DISTURBANCES WILL IMPACT THE MID-ATLANTIC REGION INTO THURSDAY WHILE BERMUDA HIGH PRESSURE PERSISTS OFFSHORE. A COLD FRONT IS EXPECTED TO MOVE ACROSS THE CENTRAL MID-ATLANTIC FROM THE WEST LATE THURSDAY INTO FRIDAY BEFORE STALLING OVER THE SOUTHERN MID-ATLANTIC FOR THE WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... BERMUDA HIGH REMAINS ANCHORED OVER THE WESTERN ATLANTIC THROUGH TONIGHT. MID-ATLANTIC REMAINS IN A WESTERLY FLOW ALOFT...WITH EMBEDDED SHORTWAVES EXPECTED TO AFFECT THE CWA. RADAR SHOWS ONE AREA OF SHOWERS ACROSS SOUTHWEST PENNSYLVANIA AND NORTHERN WEST VIRGINIA PRESSING EAST-SOUTHEAST EARLY THIS MORNING. BASED ON RADAR TRENDS EXPECT THIS LEADING WAVE OF SHOWERS TO AFFECT LOCATIONS WEST OF THE BLUE RIDGE. THERE IS SOME UNCERTAINTY HOW FAR EAST THE INITIAL AREA OF SHOWERS MAKES IT BEFORE POSSIBLY DIMINISHING. HRRR GUIDANCE SUGGESTS THIS LEADING WAVE OF SHOWERS WEAKENS OVER THE NEXT SEVERAL HOURS...SO LOWER POPS EXIST FURTHER DOWNSTREAM. HOWEVER EVEN IF THE LEADING WAVE OF SHOWERS DISSIPATES...SHORTWAVE OVER OHIO IS FORECAST TO MOVE EAST INTO THE MID-ATLANTIC FOR THIS AFTERNOON WHICH WILL SUPPORT SOME SHOWERS AND THUNDERSTORMS ACROSS THE ENTIRE CWA BY THAT TIME. WITH MORNING CLOUD COVER THIS WILL LIMIT DESTABILIZATION THIS AFTERNOON. SIMILAR TO YESTERDAY NAM SHOWS MORE CAPE THAN THE GFS...AND WAS THE BETTER CHOICE. STILL...NAM ONLY EXHIBITS ABOUT 1000 J/KG THIS AFTERNOON ALONG WITH WEAK SHEAR. THEREFORE...AM NOT EXPECTING ORGANIZED SEVERE CONVECTION BUT LOCALLY STRONGER STORMS WITH GUSTY WINDS/HEAVY DOWNPOURS CAN/T BE RULED OUT. MUCH OF THE CONVECTION SHOULD DISSIPATE BY EARLY EVENING AS THE SHORTWAVE EXITS AND THE SUN SETS. WILL CONTINUE POPS FOR SHOWERS ACROSS THE NORTHWEST PORTION OF THE CWA HOWEVER AS ANOTHER SHORTWAVE APPROACHES. FOG PRONE AREAS COULD SEE PATCHY FOG AS WELL...PARTICULARLY IF SOME CLEARING OCCURS. MET GUIDANCE PERFORMED BETTER THAN MAV GUIDANCE FOR MAXIMA YESTERDAY. IT CONTINUES TO BE THE LOWER SET OF GUIDANCE...AND WITH PLENTY OF CLOUDS TODAY WILL LEAN IN THAT DIRECTION WITH A SLIGHT UPWARD ADJUSTMENT 1-2 DEG /BUT STILL BELOW MAV/. USED AN EQUAL BLEND OF BIAS CORRECTED MET/MAV FOR MINIMA. && .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... WEDNESDAY...A SHORT-WAVE TROUGH SWINGS EAST THROUGH THE MID-ATLANTIC THROUGH THE DAY. WITH THE BERMUDA HIGH PUMPING TROPICAL MOISTURE INTO THE REGION...EXPECT DEWPOINTS IN THE LOW 70S AND PWATS OF 2.0 TO 2.2 INCHES WHICH IS NEAR TWO STANDARD DEVIATIONS ABOVE NORMAL. WITH A FOCUS OF FORCING FROM THE TROUGH AXIS...THERE IS THE POTENTIAL FOR SEVERE THUNDERSTORMS AND FLASH FLOODING ACROSS THE AREA. WILL ADD MENTION OF BOTH TO THE HWO. WITH BULK SHEAR LESS THAN 25 KT... FLASH FLOODING SHOULD BE THE GREATEST THREAT. CLOUD COVER MAY LIMIT MAX TEMPS...WENT WITH A MAV/MET BLEND THAT LEANS TOWARD MAV...GENERALLY UPR 80S WITH LOW 90S POSSIBLE IN BALT-WASH URBAN CORRIDOR. WEDNESDAY NIGHT...INSTABILITY REMAINS THROUGH THE NIGHT WITH AT LEAST ISOLATED ONGOING OR REDEVELOPING THUNDERSTORMS. MIN TEMPS HIGH WITH CLOUDS AND MOISTURE...GENERALLY LOW TO MID 70S PER MAV/MET/SREF BLEND. THURSDAY...COLD FRONT APPROACHES FROM THE WEST AS LONG WAVE TROUGH AMPLIFIES AS IT MOVES ACROSS THE MIDWEST STATES. EXPECT MORE WIDESPREAD THUNDERSTORM ACTIVITY THAN WED WITH THE FRONT ENTERING THE POTOMAC HIGHLANDS LATE IN THE AFTERNOON. SLIGHTLY MORE BULK SHEAR THAN WED AND THE FRONTAL FORCING SHOULD INCREASE THE SEVERE THREAT. SIMILAR TO WED WITH MEX/GMOS BLEND SUGGESTING A COUPLE DEGREES LESS. THURSDAY NIGHT...COLD FRONT PUSHES SE THROUGH MOST OF THE CWA BEFORE STALLING OVER SERN VA WHERE IT WILL PERSIST/UNDULATE THROUGH THE WEEKEND. ONGOING THUNDERSTORMS WILL BE SHUNTED TO SERN PORTIONS OF THE CWA...WHERE CHANCE POPS WERE MAINTAINED FOR THE LATE NIGHT. MIN TEMPS LOW 60S IN THE POTOMAC HIGHLANDS...THEN MID TO UPR 60S WEST FROM THE SHEN VLY PER MEX/SREF BLEND. && .LONG TERM /FRIDAY THROUGH MONDAY/... COLD FRONT REMAINS STALLED OVER THE DELMARVA AND SERN VA THROUGH THE WEEKEND. THE FRONT MAY RETROGRADE A BIT...RESULTING IN THUNDERSTORMS INTO THE BALT-WASH METRO...PARTICULARLY FOR SUNDAY. OTW...EXPECT DRIER CONDITIONS WITH SFC HIGH PRESSURE SHIFTING EAST ACROSS THE NRN MID-ATLANTIC. TEMPS NEAR NORMAL WITH SOME SUNSHINE. && .AVIATION /08Z TUESDAY THROUGH SATURDAY/... SHOWERS MAY REACH MRB EARLY THIS MORNING...BUT CONFIDENCE IS LOW ON THIS INITIAL BATCH HOLDING TOGETHER AS FAR EAST AS THE HUBS. SHORTWAVE MOVES THROUGH THIS AFTERNOON...WITH AT LEAST SHRA/TSRA AND WILL CONSIDER INCLUSION OF VCTS/CB FOR THE NEXT TAF CYCLE. ACTIVE WEATHER PATTERN FOR WED THROUGH THUR NIGHT WITH HEAVY THUNDERSTORMS EXPECTED. IFR CONDS IN HEAVIEST ACTIVITY. GENERALLY LIGHT SSWLY FLOW WED INTO THUR BEFORE A COLD FRONT MOVES THROUGH THE TERMINALS LATE THURSDAY. COLD FRONT STALLS JUST SE OF DC METROS FRIDAY INTO THE WEEKEND. && .MARINE... SOUTHERLY WINDS AROUND BERMUDA HIGH CONTINUES THROUGH TONIGHT. SHOULD STAY BELOW SCA TODAY...BUT THIS EVENING AND INTO THE NIGHT THERE IS A BETTER CHANCE OF HIGHER WINDS UP THE BAY ENHANCED BY CHANNELLING AND WILL RAISE SCA. SSWLY FLOW INCREASES THROUGH THE DAY WEDNESDAY. JUST THE LOWER SRN MD PORTION OF THE BAY IN SCA WED MORNING...THEN TO ALL WATERS FOR THE AFTERNOON THAT IS EXPECTED TO CONTINUE INTO THE EVENING. ACTIVE WEATHER PATTERN WITH SPECIAL MARINE WARNINGS POSSIBLE UNTIL A COLD FRONT MOVES THROUGH LATE THURSDAY NIGHT. COLD FRONT WILL STALL NEAR THE WATERS THROUGH THE WEEKEND...POTENTIALLY CONTINUING THE ACTIVE WEATHER PATTERN. && .EQUIPMENT... THE RIVER GAUGE AT FROV2 STILL IS REPORTING ERRONEOUS DATA. WE HAVE TURNED OFF THE DATA STREAM FROM THIS GAUGE. USE DATA FROM THIS SITE WITH EXTREME CAUTION. HWVR...THE BAD DATA HAS NOT BEEN INGESTED INTO RIVER FCSTS. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 2 AM EDT WEDNESDAY FOR ANZ531>533-539>541. SMALL CRAFT ADVISORY FROM 2 PM TO 6 PM EDT WEDNESDAY FOR ANZ530>533-535>542. SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 6 PM EDT WEDNESDAY FOR ANZ534-543. && $$ SYNOPSIS...BPP/BAJ NEAR TERM...BPP SHORT TERM...BAJ LONG TERM...BAJ AVIATION...BPP/BAJ MARINE...BPP/BAJ EQUIPMENT...LWX
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
526 AM EDT TUE JUL 9 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 525 AM EDT TUE JUL 9 2013 WV IMAGERY AND RUC ANALYSIS INDICATED A MAINLY ZONAL PATTERN ACROSS THE NRN CONUS WITH SEVERAL UPSTREAM SHORTWAVE TROUGHS. THE MOST PROMINENT SHRTWV WAS LOCATED OVER ERN MT WHILE A WEAKER IMPULSE AND ASSOCIATED MCS WAS MOVING THROUGH ERN SD. AT THE SFC...A WEAK FRONTAL BOUNDARY LINGERED ACROSS SRN WI WHILE A STRONGER COLD FRONT AHEAD OF THE MT SHRTWV EXTENDED FROM NW ONTARIO INTO NRN ND. A WEAK RIDGE EXTENDED FROM QUEBEC ACROSS LAKE SUPERIOR RESULTING IN LIGHT/CALM WINDS OVERNIGHT. AREAS OF FOG...LOCALLY DENSE...HAS DEVELOPED AS ABUNDANT LOW LEVEL MOISTURE LINGERED BELOW AN INVERSION ABOVE 850 MB. EXPECT THAT THE MORNING WILL BE DOMINATED BY LOW CLOUDS BUT WITH DAYTIME HEATING/MIXING THE LOW CLOUDS ACROSS MOST OF THE AREA WILL THIN OUT ENOUGH BY THIS AFTERNOON FOR TEMPERATURES TO CLIMB INTO THE LOWER 80S INLAND. SATELLITE TRENDS...SHORTER TERM MODELS AND CAPE GRADIENT...SUGGEST THAT THE ERN SD MCS WILL TRACK TO THE EAST INTO W AND SRN WI. THERE IS SOME UNCERTAINTY REGARDING THE IMPACTS OF THE MCS ON CONVECTION DEVELOPING FARTHER TO THE NORTH. THE FORCING ASSOCIATED WITH THE APPROACHING NRN PLAINS SHRTWV WITH 100M HEIGHT FALLS AND MODERATE 700-300 QVECTOR CONV WILL ALSO BE STRONGEST TO THE NORTH OF THE CWA. HOWEVER...THE SRN END OF THE SHRTWV SHOULD STILL BE STRONG ENOUGH TO SUPPORT SCT SHRA/TSRA MOVING FROM NW WI INTO WRN UPPER MI THIS AFTERNOON AND THROUGH THE REST OF THE CWA THIS EVENING. EXPECTED MAX TEMPS AND DEWPOINTS INTO THE MID TO UPPER 60S GIVE CAPE VALUES INTO THE 1K-2K J/KG RANGE...GREATEST WEST CENTRAL. 0-6KM BULK SHEAR VALUES IN THE 30-35 KNOT RANGE WILL BE MARGINAL FOR STRONG/SVR ORGANIZED CONVECTION BUT WITH TSRA MOVING THROUGH DURING PEAK HEATING GIVING DCAPE VALUES IN THE 500-1000 J/KG RANGE...SOME ISOLATED STRONG/DAMAGING WIND GUSTS MAY BE POSSIBLE WITH ANY STRONGER STORMS. THE HIGHER PROBABILITIES FOR SVR STORMS REMAINS TO THE SOUTH WHERE THE INSTABILITY IS GREATEST...PER SPC DAY1 OUTLOOK. THE SHRA/TSRA ARE EXPECTED TO PROGRESS THROUGH THE AREA MOVING INTO THE ERN CWA LATE THIS EVENING AND ENDING OVERNIGHT. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 525 AM EDT TUE JUL 9 2013 AFTER A FEW DAYS OF WARM AND ACTIVE WEATHER WITH POCKETS OF HEAVY RAIN OVER MAINLY WESTERN HALF OF CWA...DEVELOPING TROUGHING ALOFT ACROSS THE GREAT LAKES AND SFC HIGH ON THE WESTERN EDGE OF THE TROUGH ALOFT WILL BRING QUIET AND COOLER WEATHER MID TO LATE WEEK. WARMER TEMPERATURES AND INCREASING SHRA/TSRA CHANCES RETURN FOR THE WEEKEND AS UPPER HEIGHTS BECOME MORE ZONAL. OVERALL AGREEMENT THAT BEST CHANCE OF SHRA/TSRA ON WEDNESDAY WILL BE 12-15Z OVER THE FAR EASTERN CWA. STRONGER TSRA STILL POSSIBLE WITH MUCAPE UP TO 800J/KG. BETTER SHOT FOR SVR WILL BE FARTHER SOUTH OVER SOUTHERN WI/NORTHERN IL CLOSER TO WEST-EAST FRONTAL BOUNDARY AND ON NORTHERN GRADIENT OF HIGHER MLCAPES OVR 1000J/KG. ANY CHANCES OF SHRA/TSRA OVER EAST QUICKLY END THROUGH MORNING AS STRONG DEEP LAYER Q-VECTOR DIVERGENCE/SUBSIDENCE SURGES ACROSS UPPER GREAT LAKES. PRESSURE GRADIENT BRIEFLY BECOMES TIGHT BTWN THE EXITING LOW PRESSURE TROUGH AND HIGH PRESSURE BUILDING OVER THE PLAINS. EXPECT BRIEF BUILDING WAVES AND INCREASED SWIM RISK FOR WEDNESDAY OVER THE LK SUPERIOR BEACHES OF ALGER COUNTY AS WINDS WILL BE FROM THE WEST TO NORTHWEST. WINDS/WAVES AND ASSOCIATED HIGHER SWIM RISK SUBSIDES BY LATE AFTN WITH LOSS OF PRESSURE RISES AND TIGHTER PRESSURE GRADIENT. HIGH PRESSURE REMAINS MAIN WEATHER FEATURE FOR THU/FRI. TEMPS MAY DROP INTO THE LOW-MID 40S OVER INTERIOR COOL SPOTS ON THURSDAY NIGHT WITH LGT SOUTHERLY FLOW AS RIDGE AXIS DRIFTS ACROSS. AIRMASS DOES NOT APPEAR TO BE NEARLY COLD OR DRY ENOUGH FOR ANY FROST POTENTIAL. HIGH TEMPS BOTH DAYS SHOULD TOP OUT IN THE MID-UPR 70S AWAY FROM THE GREAT LAKES. MAY EVEN SEE A FEW SPOTS BACK NEAR 80 DEGREES BY THURSDAY. UNCERTAINTY ABOUNDS WITH TIMING AND EXTENT OF NEXT ROUND AND/OR ROUNDS OF SHRA/TSRA THIS WEEKEND INTO NEXT MONDAY. ECMWF NORMALLY LEADS WAY IN TERMS OF VERIFICATION...BUT BOY ARE ITS SOLUTIONS IN THE LAST COUPLE DAYS QUITE INCONSISTENT IN TERMS OF TIMING FOR THE WEEKEND SHRA/TSRA CHANCES. DOES SEEM LIKE ECMWF IS TRENDING TOWARD SLOWER IDEA SHOWN BY GFS FOR ARRIVAL OF PRECIP FRIDAY NIGHT. WILL START TO SHOW TREND OF CHANCE POPS ONLY OVER THE FAR WEST LATE ON FRIDAY NIGHT WHILE IT STAYS MAINLY DRY ELSEWHERE. UPPER HEIGHTS FLATTEN OUT SATURDAY ALLOWING SHORTWAVES AND MID-LEVEL WIND MAX TO SLIDE ACROSS UPPER GREAT LAKES REGION. MAIN SFC LOW WILL BE WELL TO NORTH CLOSER TO SHARPER TROUGH ALOFT...BUT SW LOW-LEVEL FLOW ALONG WITH INCREASING MOISTURE AND BUILDING INSTABILITY JUST UPSTREAM SHOULD RESULT IN AT LEAST A CHANCE OF SHRA/TSRA AHEAD OF SFC-H85 TROUGH THAT MOVES THROUGH BY SUNDAY MORNING. WITH WRLY FLOW ALOFT...FRONT MAY END UP STALLING OUT LATER IN THE WEEKEND PROVIDING A FOCUS FOR ADDITIONAL SHRA/TSRA. FOR MOST PART USED CONSENSUS POPS...BUT DID INCREASE POPS SLIGHTLY OVER THE SOUTH AND EAST CWA CLOSER TO EXPECTED POSITION OF FRONT PER WPC HAND DRAWN SFC PROGS. BASED ON GENERAL S/SW GRADIENT FLOW AHEAD OF FRONT AND H85 TEMPS IN THE MID TEENS...INCREASED TEMPS OVER CONSENSUS GUIDANCE. EXPECT MAX TEMPS FRIDAY THROUGH SUNDAY IN THE MID-UPR 70S TO AS WARM AS MID 80S. IT WILL ALL DEPEND ON EXTENT OF CLOUDS AND SHRA/TSRA. AFTER MIN TEMPS IN THE 40S AND 50S MUCH OF THIS WEEK...READINGS RETURN TO THE WARMER/MUGGIER 60S BY THE WEEKEND. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 126 AM EDT TUE JUL 9 2013 EXPECT DENSE FOG/VLIFR CONDITIONS TO IMPACT ALL 3 TAF SITES EARLY THIS MRNG WITH LGT WINDS/HUMID LLVLS UNDER SFC HI PRES/DRIER AIR ALF DEPICTED ON THE 00Z GRB RAOB. DIURNAL HEATING LATER THIS MRNG SHOULD ALLOW A GRADUAL RETURN OF VFR WX...FASTEST BY NOON AT IWD WITH DVLPG DOWNSLOPE S WIND IN ADVANCE OF APRCHG UPR DISTURBANCE/COLD FNT. SOME SHRA/TS IN ADVANCE OF THESE FEATURES WL ARRIVE OVER THE WRN IWD/CMX SITES BY THE END OF THE TAF PERIOD AND THEN MOVE E TOWARD SAW DURING THE EVNG. ALTHOUGH THE RELATIVE DRYNESS OF THE LLVLS SHOULD ALLOW PREDOMINANT VFR CONDITIONS...POORER CONDITIONS WL BE PSBL UNDER THE HEAVIER SHRA/TS. UPSLOPE WNW FLOW OFF LK SUP IN THE WAKE OF THE CONVECTION MIGHT CAUSE PREDOMINANT MVFR WX AT CMX...ESPECIALLY IF HEAVIER RA FALLS NEARBY. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 359 PM EDT MON JUL 8 2013 DENSE FOG REMAINS A CONCERN ACROSS LAKE SUPERIOR THROUGH TUESDAY MORNING. LIGHT WINDS AND LITTLE AIR MASS MOVEMENT WILL ALLOW FOR THE REDEVELOPMENT OF AREAS OF DENSE FOG OVERNIGHT. CLEARING SKIES FOR TUESDAY MORNING SHOULD ALLOW ENOUGH HEATING TO MIX OUT THE MOST DENSE FOG BY TUESDAY AFTERNOON. PATCHY FOG WILL THEN LINGER INTO WEDNESDAY BEFORE A COLD FRONT BRINGS DRIER AIR FROM WEST TO EAST ACROSS THE LAKE. WINDS SHOULD BE LIGHT AND GENERALLY VARIABLE THROUGH TUESDAY EVENING. THEN...EXPECT WINDS TO VEER TO THE NW AT 15 TO 25 KNOTS...MAINLY ACROSS THE EAST HALF OF THE LAKE...FOR LATE TUESDAY NIGHT THROUGH WEDNESDAY. HIGH PRESSURE WILL THEN BUILD INTO THE AREA THURSDAY THROUGH SATURDAY AND BRING LIGHT WINDS UNDER 15 KNOTS FOR MUCH OF THE TIME PERIOD. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... DENSE FOG ADVISORY UNTIL 5 PM EDT /4 PM CDT/ THIS AFTERNOON FOR LSZ162-240>251-263>267. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...JLA AVIATION...KC MARINE...KLUBER
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
412 AM CDT TUE JUL 9 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 410 AM CDT TUE JUL 9 2013 MAIN CONCERN IN THE SHORT TERM REVOLVES ON EVOLUTION OF STORMS CURRENTLY ACROSS THE DAKOTAS THROUGH THE MORNING...FOLLOWED BY WHERE THUNDERSTORMS REDEVELOP THIS AFTERNOON AND TRAVEL THIS EVENING. IT IS THE AFTERNOON/EVENING ACTIVITY THAT WILL ALSO HAVE A SEVERE THREAT. WIND AND HAIL WILL BE THE PRIMARY THREATS...THOUGH DEPENDING ON WHERE BOUNDARIES ARE LEFT OVER FROM CONVECTION THIS MORNING...THERE WILL ALSO BE THE SMALL CHANCE FOR TORNADOES ON ANY LEFT OVER OUTFLOW BOUNDARIES. AT 3 AM...WE WERE DEALING WITH A BIFURCATED LLJ IN TERMS OF MOISTURE TRANSPORT MAXIMA...WITH ONE BRANCH DRIVING CONVECTION CURRENTLY MOVING ACROSS THE DAKOTAS AND THE OTHER DRIVING ANOTHER CLUSTER ALONG THE NEB/IA BORDER. THIS SRN BRANCH WILL TRACK ACROSS IA THROUGH THE MORNING...KEEPING THAT CONVECTION SOUTH OF MN WHILE BECOMING THE MAIN LLJ FOR POTENTIAL AFTERNOON ACTIVITY. FOR THE MPX AREA...IT IS THE MCS THIS MORNING OVER SODAK THAT WILL BE OUR PROBLEM. 3Z RAP MUCAPE ANALYSIS SHOWS A RIBBON OF 1000-1500 J/KG OF MUCAPE EXTENDING FROM THE MADISON/CANBY AREA...ESE TROUGH ROCHESTER AND LA CROSSE. AS A RESULT...ANTICIPATE THIS BAND OF THUNDERSTORMS WILL CONTINUE ESE ALONG THIS CAPE GRADIENT. AT ITS CURRENT PACE...SHOULD ENTER WRN MN SHORTLY BEFORE 5 AM...REACH THE I-35 CORRIDOR BETWEEN 7 AND 8 AM AND EVENTUALLY THE LSE/EAU AREAS BY LATE MORNING. THE BULK OF THE CONVECTION WITH THIS LINE SHOULD TRACK SOUTH OF I-94 THIS MORNING. AS FOR SEVERE THREAT...THE STRONG/SEVERE LINE OF STORMS THAT MOVED ACROSS SODAK HAS NOW MERGED WITH THE WAA ACTIVITY THAT HAD DEVELOPED OUT AHEAD OF IT...WITH ONE LINE NOW EVIDENT ON REGIONAL RADAR ANALYSIS. WILL HAVE TO WATCH HOW THIS LINE EVOLVES OVER THE NEXT HOUR TO SEE WHAT KIND OF SEVERE THREAT IT WILL POSE. IN THE NEXT HOUR...IF IT BEGINS TO BOW OUT AND ACCELERATE...THEN A WIND THREAT WILL EXIST THROUGH THE MORNING AS IT TRACKS ACROSS MN. WITH THE RAP AT 3Z ANALYZING 20-30 KTS OF 0-3KM SHEAR OUT AHEAD OF THE SYSTEM...IT IS PLAUSIBLE THAT THAT COULD HAPPEN...THOUGH IN THE END IT MAY BE DIFFICULT TO GET ANY SEVERE STRENGTH WINDS THROUGH THE STABLE BOUNDARY LAYER...SO AGREE WITH SPC MCD THAT SEVERE THREAT WILL BE FAIRLY MARGINAL. FOR THIS AFTERNOON...MANY A QUESTION MARKS STILL REMAIN IN PLACE. THIS BIGGEST ISSUE IS HOW WILL STORMS THIS MORNING IMPACT WHAT HAPPENS LATER. THE MAIN QUESTION IS DOES THE ATMOSPHERE HAVE ENOUGH TIME TO RECHARGE FROM STORMS MOVING THROUGH LARGELY IN THE 10-18Z TIME FRAME? FIRST WORD OF WARNING FOR THE ARM CHAIR FORECASTERS OUT THERE...THE CAMS MAY NOT BE ALL THAT RELIABLE FOR WHAT HAPPENS LATER THIS AFTERNOON AS ALL OF THEM ARE HANDLING CURRENT CONVECTION QUITE POORLY /INCLUDING ALL MEMBERS OF THE 3Z HOPWRF/. PROBLEM IS...OUTSIDE OF THE SPCWRF...NONE OF THE CAMS SNOW THUNDERSTORMS MOVING ACROSS THE AREA OUTLINED IN THE PARAGRAPH ABOVE...MANY /INCLUDING THE HOPWRF MEMBERS/ HAVE NOTHING MOVING ACROSS THE MPX AREA THIS MORNING...SO HARD TO PUT MUCH STOCK IN WHAT THEY ARE DOING THIS AFTERNOON. THE ONLY ONE TO BE SOMEWHAT CLOSE TO REALITY THIS MORNING /SPCWRF/...SHOWS VERY LITTLE CONVECTION REDEVELOPING IN THE MPX AREA THIS AFTERNOON. CERTAINLY A BIG PLUS FOR THE AFTERNOON...IS OVER THE LAST 24 HOURS...MODELS HAVE SLOWED UP THE PROGRESSION OF THE FRONT ACROSS THE MPX AREA...WHICH LIKELY EXPLAINS WHY HIGHER SEVERE PROBABILITIES WERE PULLED NORTHWEST WITH THE DAY1 SPC CONVECTIVE OUTLOOK. CURRENT MODEL BLEND WOULD SAY THE FRONT MOVES INTO THE NW MPX CWA AROUND 20Z...THE TWIN CITIES AROUND 00Z AND FINALLY CLEARS EAU AREA SHORTLY AFTER 3Z. THIS PUTS THE FRONT ACROSS MUCH OF THE AREA DURING PEAK HEATING...THOUGH IT IS STILL DEBATABLE HOW MUCH HEATING WE WILL SEE BEHIND THE MORNING CONVECTION. IF CURRENT FORECAST WERE TO HOLD...WITH TEMPERATURES REBOUNDING INTO THE MID 80S TO NEAR 90...WITH DEWPS IN THE LOWER 70S...THEN WE SHOULD HAVE NO PROBLEM GENERATING 2000-3500 J/KG OF MLCAPE AHEAD OF THE BOUNDARY AS THE NAM/GFS DO. FROM THE SHEAR PERSPECTIVE...A 40-60 KT MID LEVEL JET MOVING IN WITH THE UPPER WAVE THIS AFTERNOON/EVENING WILL PROVIDE PLENTY OF DEEP LAYER SHEAR TO SUPPORT UPDRAFT ROTATION AND STORM ORGANIZATION...BUT THE 0-3KM SHEAR IS LOOKING MORE SUSPECT ACROSS THE MPX AREA TO REALLY DRIVE UP A TORNADO THREAT. THE REASON FOR THE POOR LOW LEVEL SHEAR IS THAT THE PRESSURE PATTERN AHEAD OF THE FRONT WILL BE FAIRLY BAGGY...WITH LIGHT PREFRONTAL WINDS EXPECTED. IN ADDITION...THE CORE OF A 30-40 KT LLJ WILL EXTEND FROM CENTRAL IA TOWARD NE WIS...STAYING JUST SE OF THE MPX AREA. COMBINED...THE WEAK SFC WINDS AND BETTER LLJ BEING JUST SE OF THE MPX CWA RESULT IN MARGINAL 0-1 KM AND 0-3 KM SHEAR /MAINLY 20 KTS OR LESS/. BESIDE THE WEAKER SHEAR...THE WEAK SFC WINDS OUT AHEAD OF THE FRONT WILL ALSO LIMIT THE AMOUNT OF CONVERGENCE ALONG IT...WHICH MAY HELP EXPLAIN WHY MANY OF THE CAMS /OUTSIDE OF THE 3Z HOPWRF/ STRUGGLE TO GENERATE MUCH CONVECTION ALONG THE BOUNDARY THIS AFTERNOON. IN SUMMARY...CONFIDENCE IS HIGH THAT MCS CURRENTLY OVER ERN SODAK WILL TRACK ACROSS AREAS SOUTH OF I-94 THIS MORNING. BECAUSE OF THIS...CONFIDENCE IN HOW THE AFTERNOON PLAYS OUT IS CONSIDERABLY DIMINISHED. BUT...GIVEN FRONTAL TIMING...EXPECT AT LEAST SCT STORMS TO DEVELOP ALONG THE FRONT BETWEEN 19Z AND 21Z THAT WILL THEN TRACK SE THIS EVENING WITH THE FRONT. GIVEN DEGREE OF INSTABILITY AND BULK SHEAR...LARGE HAIL AND DAMAGING WINDS WILL BE THE PRIMARY THREAT. THE WEAKER LOW LEVEL SHEAR MEANS THAT UNLESS A STORM CAN LATCH ON TO A REMNANT OUTFLOW BOUNDARY...THE TORNADO THREAT APPEARS TO BE RELATIVELY LOW...THOUGH NOT NEGLIGIBLE. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 410 AM CDT TUE JUL 9 2013 THE FIRST HALF OF THE PERIOD WILL START OFF DRY AS LARGE SCALE SUBSIDENCE DOWNSTREAM OF THE UPPER LEVEL RIDGE AXIS BUILDS AN AREA OF SURFACE HIGH PRESSURE ACROSS THE UPPER MIDWEST. FORECAST SOUNDINGS SHOW A DRY PROFILE WITH PWATS ONLY AROUND 0.75 INCHES...ALONG WITH LITTLE POTENTIAL FOR CLOUDS DURING THE DAY ON WEDNESDAY. WINDS WILL GO CALM OVERNIGHT ALLOWING AN INVERSION TO SET UP AND TEMPERATURES TO COOL DOWN TO THE UPPER 50S ACROSS MOST LOCATIONS...WITH LOW 60S EXPECTED IN AND AROUND THE METRO DO TO THE HEAT ISLAND. THURSDAY WILL BE DRY AS WELL WITH THE SURFACE HIGH STILL SUPPRESSING ANY CHANCE OF PRECIP. BY THURSDAY NIGHT THE SURFACE HIGH WILL DRIFT EASTWARD AS THE THERMAL RIDGE APPROACHES FROM THE WEST...AND SOUTHERLY WINDS ON THE BACK SIDE WILL KEEP OVERNIGHT LOWS IN THE MID TO UPPER 60S ACROSS WESTERN MINNESOTA. FRIDAY SHOULD BE MUCH WARMER THAN CURRENTLY FORECAST BY THE NUMERICAL MODELS. BOTH THE GFS AND ECMWF 09.00 HAVE H850 TEMPS 20-22C...WITH SOUTHERLY WINDS OF 30KTS...YET FOR SOME REASON THE FORECAST SOUNDINGS ONLY SHOW MIXING UP TO AROUND 900MB. THIS IS CONTRADICTORY TO THE SIMPLE PROPERTIES THAT GOVERN THE ATMOSPHERE. GIVEN A MID JULY PROFILE THAT IS CLOUD FREE...TOGETHER WITH THE POTENTIAL FOR MECHANICAL MIXING...HAVE VERY HIGH CONFIDENCE THAT AFTERNOON TEMPERATURES WILL CLIMB INTO THE 90S ACROSS SOUTHWEST MINNESOTA. ON SATURDAY CONFIDENCE IN TEMPERATURES DECREASES CONSIDERABLY AS A FRONTAL BOUNDARY/TROUGH OF LOW PRESSURE STALLS OUT FROM SOUTHWEST TO NORTHEAST OVER THE UPPER MIDWEST. THIS WILL INTRODUCE CHANCES FOR SHOWERS AND THUNDERSTORMS...WHICH WILL GREATLY AFFECT AFTERNOON HIGHS. THEREFORE DID NOT STRAY TOO MUCH FROM BLENDED GUIDANCE...AND CONTINUE TO HAVE CHANCES FOR PRECIP INTO EARLY NEXT WEEK. THE BEST CHANCE FOR RAIN...WITH 1-3 INCH AMOUNTS VERY LIKELY AT A FEW LOCATIONS ACROSS THE NORTHWEST NEAR CANBY/ALEXANDRIA/ST CLOUD...WILL BE LATE FRIDAY NIGHT INTO SATURDAY MORNING. LOOKING AHEAD...THE THERMAL RIDGE WILL TAKE ON A POSITIVE TILT OVER THE UPPER MISSISSIPPI RIVER VALLEY. ON SUNDAY THE ECMWF DRIVES A SHORTWAVE ALONG THE US/CANADIAN BORDER THAT SUPPRESSES THE RIDGE...WHILE THE GFS IS A DAY SLOWER WITH THIS FEATURE. ALSO...AS ALLUDED TO EARLIER OVERCAST SKIES WILL GREATLY IMPACT HIGH TEMPS SO DID NOT HAVE THE CONFIDENCE TO DEVIATE FROM A CONSENSUS APPROACH. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY MORNING) ISSUEDAT 1002 PM CDT MON JUL 8 2013 CONVECTION CONTINUES TO INCREASE ACROSS THE DAKOTAS LATE THIS EVENING. SHORT TERM PROJECTIONS SHOW SCT SHRA/TSRA POTENTIALLY REACHING KAXN AND KRWF BY 08Z...KSTC BY 10Z AND THE TWIN CITIES BY 12Z. ADJUSTED TIMES IN THE CURRENT TAF PACKAGE TO REFLECT THIS. THERE REMAINS THE THREAT OF FOG OVERNIGHT...FROM KSTC TO KEAU. THE INCREASE IN CLOUDS AND THE THREAT OF SHOWERS SHOULD LIMIT HOW LOW THE VSBY DROPS AT KSTC AND KRNH. KEAU REMAINS THE PRIME LOCATION FOR IFR OR LOWER BR/FG BETWEEN 09Z AND 12Z. SHOWERS AND A FEW THUNDERSTORMS SHOULD MOVE ACROSS KRNH AND KEAU TUESDAY MORNING. MORE ACTIVITY WILL DEVELOP AHEAD OF AN APPROACHING COLD FRONT TUESDAY AFTERNOON. THIS SHOULD START EARLY IN THE AFTERNOON AROUND KAXN...KRWF AND KSTC AND REACH THE TWIN CITIES AN WESTERN WI BY LATE AFTERNOON/EARLY EVENING. INCREASING NW WINDS OF 10 TO 20 KNOTS IN THE WAKE OF THE FRONT FOR TUESDAY NIGHT. KMSP... SCT SHRA/TSRA EXPECTED TO PUSH THROUGH THE TWIN CITIES IN THE 12Z-15Z TIME FRAME WITH LINGERING SHOWERS THROUGH THE LATE MORNING HOURS. A COLD FRONT WILL APPROACHING FROM THE WEST DURING THE LATE AFTERNOON (21Z). MORE SHRA/TSRA EXPECTED ALONG AND AHEAD OF THE FRONT WITH FRONTAL PASSAGE STILL LOOKING TO BE AROUND 01Z. INCREASING NW WINDS OF 15-20 KNOTS BY LATE EVENING AND CONTINUING OVERNIGHT. /OUTLOOK FOR KMSP/ WED...VFR. WINDS NW 10G20KTS. THU...VFR. WINDS LGT AND VRB. FRI...VFR. WINDS S 10-15KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...MPG LONG TERM...JRB AVIATION...MPG
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1255 AM CDT TUE JUL 9 2013 .UPDATE... ISSUED AT 1255 AM CDT TUE JUL 9 2013 LLJ-DRIVEN SHWRS/TSTMS AND THEIR REMNANTS CONTINUE MOVING E AT 26 KTS. THEIR HIGH-BASED NATURE IS LIMITING RFALL AMTS TO AROUND .1" WITH UP TO .2" FOR THE LUCKIEST SPOTS. NOT EXPECTING ANY SVR BUT WE WILL NEED TO KEEP AN EYE FOR HEAT BURST ACTIVITY...PRIMARILY OVER N-CNTRL KS WHERE PCPN COVERAGE IS LEAST BUT THE INVERTED-V THERMODYNAMIC PROFILE IS PRESENT. THE MOST SHORT-TERM ADJUSTMENTS WERE TO BEST RECONFIGURE POPS BASED ON 88D TRENDS AND WE WILL PROBABLY NEED TO MAKE FURTHER ADJUSTMENTS AS THE NGT WEARS ON. OTHERWISE...LOW TEMPS APPEAR ON TRACK. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 455 PM CDT MON JUL 8 2013 PLENTY OF THINGS TO PONDER DURING THE NEXT 24 HOURS...INCLUDING AT LEAST ONE CONDITIONAL RISK FOR SEVERE STORMS THIS EVENING...AND MAYBE ANOTHER SEVERE RISK ON TUESDAY AFTERNOON/EVENING...ALTHOUGH CONFIDENCE IS QUITE LOW ON THE LIKELIHOOD/EVOLUTION OF THE LATTER. IN OTHER DEPARTMENTS...TOMORROW IS CURRENTLY EXPECTED TO BE THE OVERALL-HOTTEST AFTERNOON OF THE SUMMER SO FAR FOR MOST OF THE CWA...AND A HEAT ADVISORY HAS BEEN ISSUES FOR SEVERAL SOUTHERN/SOUTHEAST COUNTIES. 21Z OBJECTIVE SURFACE ANALYSIS HIGHLIGHTS A SOMEWHAT SUBTLE-BUT EVIDENT EAST-WEST QUASI STATIONARY GENERALLY STRETCHED ACROSS THE SOUTHERN HALF OF NEBRASKA. IN THE WIND-FIELD...THIS BOUNDARY SEPARATES A STEADY 15+ MPH SOUTHERLY BREEZE IN NORTH CENTRAL KANSAS...FORM A LIGHTER...GENERALLY EAST-SOUTHEAST BREEZE WITHIN MOST OF THE NEBRASKA CWA. ITS ALSO SOMEWHAT OF A MOISTURE BOUNDARY...WITH MID-50S TO LOW 60S DEWPOINTS RESIDING IN THE DEEPLY MIXED AIRMASS TO THE SOUTH...AND HIGHER DEWPOINTS MID-60S TO NEAR 70 MOST AREAS ALONG/NORTH OF I-80. AS DISCUSSED EARLIER TODAY...NEAR-CRITICAL FIRE DANGER WILL PERSIST FOR A FEW MORE HOURS ESPECIALLY IN THE PHILLIPS/ROOKS COUNTY AREA IN KS. HIGH TEMPS THIS AFTERNOON WORKED OUT PRETTY WELL ACROSS THE SOUTHWESTERN 2/3 OF THE CWA RANGING GENERALLY 95-104 DEGREES...WHILE SOME NORTHEAST AREAS ARE STRUGGLING TO REACH 90 THANKS IN PART TO A BATCH OF MID LEVEL CLOUDS THAT FORMED ON THE BACK-SIDE OF AN MCV THAT HAS MOVED WELL EAST INTO WESTERN IA. ALOFT...WATER VAPOR IMAGERY AND SHORT TERM MODEL DATA CONFIRM CONTINUED QUASI-ZONAL FLOW ACROSS THE LOCAL AREA...BETWEEN THE LARGER-SCALE MID LEVEL RIDGE AXIS STRETCHED WEST-EAST FROM AZ TO OK...AND A VIGOROUS SHORTWAVE TROUGH MAKING ITS WAY ACROSS THE ID/MT/CANADA BORDER AREA. THE MAIN LOW-AMPLITUDE SHORTWAVE TROUGH OF INTEREST FOR THIS EVENING IS CURRENTLY LIFTING OUT OF WY INTO WESTERN NEB/SD. LATE THIS AFTERNOON INTO THIS EVENING...THE PRIMARY FOCUS IS ON HOW MUCH THUNDERSTORM COVERAGE THE CWA WILL SEE...AND WHETHER SOME OF THIS ACTIVITY COULD BECOME SEVERE. AT PRESENT TIME...RADAR INDICATES A FEW WEAK-ISH/HIGH-BASED STORMS NEAR THE STATE LINE IN THE SOUTHWESTERN CWA...LARGELY A RESULT OF VERY STEEP LOW-LEVEL LAPSE RATES IN THE HOT/DEEPLY MIXED AIRMASS OVER KS. MEANWHILE...OFF TO THE NORTHWEST...A FEW STRONG TO SEVERE STORMS HAVE TAKEN OFF IN NORTH CENTRAL/WESTERN NEB...IN AN ENVIRONMENT CHARACTERIZED BY AROUND 2000+ J/KG MLCAPE AND 30+ KNOTS OF 0-6KM DEEP LAYER SHEAR. LOCALLY...WITH THE EXCEPTION OF THE HIGH-BASED STORMS IN OUR SOUTH...MODEL SOUNDINGS SUGGEST THERE IS JUST ENOUGH OF A CAP IN PLACE TO KEEP CONVECTION FROM DEVELOPING OVERHEAD IN MOST OF THE CENTRAL/NORTHERN CWA...AIDED IN PART BY SUBSIDENCE BEHIND THE DEPARTING MCV. AS HAS BEEN THE CASE FOR DAYS NOW...CONFIDENCE IN THE DETAILS IS LOW IN THIS WEAKLY FORCED PATTERN...BUT TAKING CUE FROM THE LATEST RAP/HRRR AND 12Z 4KM WRF- NMM...THE GENERAL EXPECTATION IS FOR MOST OF THE CWA TO REMAIN STORM FREE THROUGH AT LEAST 00Z/7PM...BEFORE STORM CHANCES GRADUALLY INCREASE THROUGH THE EVENING HOURS ESPECIALLY NEAR/NORTH OF I-80...AND LIKELY MAINLY AS A FUNCTION OF ACTIVITY MOVING IN FROM WESTERN NEBRASKA...ALTHOUGH LOCAL INITIATION NEAR THE SURFACE BOUNDARY CANNOT BE RULED OUT EITHER. BOTH THE WRF-NMM AND HRRR ARE FAIRLY AGGRESSIVE BRINGING A CLUSTER OF STORMS...POSSIBLY A SEMI- ORGANIZED MCS ACROSS ESPECIALLY THE NORTHERN 1/2 OF THE CWA THIS EVENING...BUT A SIMILAR MODEL DEPICTION YESTERDAY ENDED UP BEING A BIT OVERDONE...AND THUS HAVE CAPPED POPS AT NO HIGHER THAN 50 PERCENT AT LEAST FOR NOW. WITH MLCAPE REMAINING 1000+ J/KG WELL INTO THE EVENING HOURS AND WITH AT LEAST MODEST SHEAR...AT LEAST A LOCALIZED LARGE HAIL AND ESPECIALLY A WIND THREAT IS QUITE POSSIBLE ESPECIALLY IF STORMS TO THE WEST CAN ORGANIZE AND DEVELOP A COLD POOL. AGREE WITH SPC IN HIGHLIGHTING THE NORTHERN 1/2 OF THE CWA FOR THE GREATEST SEVERE THREAT...BUT JUST CANNOT RULE OUT A STRONG TO SEVERE STORM ANYWHERE IN THE CWA THIS EVENING. ALTHOUGH THE MAIN SEVERE THREAT SHOULD BE ON THE WANE BY MIDNIGHT...LINGERED LOW POPS THROUGH THE NIGHT ESPECIALLY ACROSS THE EASTERN 2/3 OF THE CWA TO ACCOUNT FOR ACTIVITY PERSISTING OR NEWLY-DEVELOPING WITHIN THE LOW LEVEL JET AXIS...AND JUST AHEAD ON APPROACHING COLD FRONT. IF NOTHING ELSE...HOPEFULLY PARTS OF THE CWA CAN RECEIVE SOME MUCH-NEEDED RAINS TONIGHT...BECAUSE THIS MAY BE ONE OF THE BETTER CHANCES FOR AWHILE. TEMPERATURE-WISE...MADE ONLY MINOR TWEAKS TO LOWS...WITH THE PREVALENT LIGHT SOUTHERLY BREEZE HOLDING MOST AREAS UP INTO THE 70-75 RANGE. ALTHOUGH AT LEAST LIGHT FOG DEVELOPMENT CANNOT BE RULED OUT LATE TONIGHT ESPECIALLY IN AREAS THAT RECEIVE RAIN...THE PROBABILITY/MAGNITUDE SEEMED LOW ENOUGH TO OMIT FROM THE FORECAST. TURNING TO TUESDAY DAYTIME...REALLY DON/T THINK SEVERE STORMS ARE GOING TO END UP BEING MUCH OF A STORY...AT LEAST THROUGH THE VAST MAJORITY OF THE DAY. ALOFT...QUASI-ZONAL FLOW WILL START TO TURN A BIT MORE NORTHWESTERLY IN RESPONSE TO THE PASSAGE OF A FAIRLY VIGOROUS SHORTWAVE TROUGH FROM EASTERN MT TOWARD NORTHERN MN. AT THE SURFACE...A FAIRLY WEAK COLD FRONT...MORE EVIDENT IN THE WIND FIELD THAN ON A THERMOMETER...WILL WORK SOUTHWARD ACROSS THE CWA AS THE DAY WEARS ON...WITH MOST AREAS SEEING A FEW HOURS OF LIGHT/VARIABLE WINDS BEFORE A SLIGHTLY MORE STEADY NORTHERLY BREEZE SETTLES IN. ALONG AND ESPECIALLY JUST AHEAD OF THIS BOUNDARY...A LOW LEVEL THERMAL RIDGE WILL EXTEND INTO THE CWA FROM THE SOUTHWEST...PROMOTING WHAT SHOULD BE THE HIGHEST HEAT-INDEX READINGS OF THE SUMMER SO FAR FOR MOST ALL OF THE CWA...AND IN SOME SPOTS THE HOTTEST ACTUAL AIR TEMPERATURES. THE ONLY CAVEATS WOULD BE AN UNEXPECTEDLY STRONG OUTFLOW BOUNDARY FROM CONVECTION TONIGHT THAT MIGHT HELP ACCELERATE THE COLD FRONT SOUTHWARD FASTER...AND MAYBE A DENSER-THAN-EXPECTED COVERAGE OF MID LEVEL CLOUDS OR LINGERING WEAK CONVECTION. BUT ASSUMING NEITHER ONE OF THESE CAVEATS PLAY OUT...HAVE AIMED FOR ACTUAL HIGH TEMPS RANGING FROM MID 90S NORTH...UPPER 90S CENTRAL...AND 100-106 NEAR AND SOUTH OF THE STATE LINE. HEAT INDEX VALUES OF 100+ ARE FORECAST ACROSS MUCH OF THE SOUTHERN AND EASTERN HALVES OF THE CWA...AND HAVE ISSUED A HEAT ADVISORY FOR ALL KS ZONES ALONG WITH WEBSTER- NUCKOLLS-THAYER IN NEBRASKA...WHICH HAVE THE HIGHEST LIKELIHOOD OF REACHING OR EXCEEDING A 105 HEAT INDEX. FORTUNATELY FOR FIRE WEATHER CONCERNS IN THE FAR SOUTHWEST COUNTIES...SUSTAINED WINDS/GUSTS DO NOT LOOK TO EXCEED 20 MPH DURING THE PEAK OF AFTERNOON HEATING. AS FOR CONVECTIVE CHANCES...FORECAST SOUNDINGS SUGGEST THAT A FAIRLY STRONG CAP SHOULD PREVAIL THROUGH THE DAY AS VERY WARM MID LEVEL TEMPS OVERSPREAD THE AREA. AS A RESULT...OTHER THAN A LINGERING SLIGHT CHANCE OF MORNING STORMS IN EASTERN COUNTIES RIGHT AWAY IN THE MORNING...WILL AIM FOR A DRY MAJORITY OF THE DAY...BEFORE BRINGING BACK SLIGHT STORM CHANCES POST- 21Z/4PM. THERE ARE AT LEAST TWO POSSIBLE FOCUSES FOR LATE AFTERNOON DEVELOPMENT...THE MAIN COLD FRONT WHICH SHOULD BE VERY NEAR THE FAR SOUTHEAST CORNER OF THE CWA...AND ALSO FORCING FROM THE SOUTHERN EDGE OF THE NORTHERN PLAINS SHORTWAVE TROUGH...WHICH COULD KICK OFF CONVECTION CLOSER TO THE NORTHERN EDGE OF THE CWA. HOWEVER...MODELS SUCH AS THE 12Z 4KM WRF-NMM ADVERTISE ESSENTIALLY NO LATE AFTERNOON STORMS ANYWHERE IN THE CWA...SO THUS ONLY THE SLIGHT POPS. IF STORMS WOULD MANAGE TO FORM...A CONDITIONAL SEVERE THREAT COULD EXIST ALMOST ANYWHERE IN THE CWA...POTENTIALLY EVEN WEST OF THE SPC DAY 2 SLIGHT RISK AREA. PLENTY OF UNCERTAINTY FOR SURE. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 455 PM CDT MON JUL 8 2013 MAIN FORECAST CONCERNS WILL BE CHANCES FOR THUNDERSTORMS TUESDAY NIGHT AND WEDNESDAY NIGHT AND AGAIN SATURDAY NIGHT THROUGH MONDAY AND TEMPERATURES. MODELS ARE FAIRLY SIMILAR IN BUILDING AN UPPER LEVEL RIDGE ACROSS THE AREA DURING THE PERIOD...BUT THE DETAILS OF THE TIMING MAINLY WEAK UPPER LEVEL WAVES THROUGH THE AREA ARE SOMEWHAT DIFFERENT BETWEEN THE MODELS. THIS BRINGS SOME UNCERTAINTY IN WHEN THERE WILL BE SOME CHANCES FOR THUNDERSTORMS. A SURFACE COLD FRONT WILL MOVE TO THE SOUTH ACROSS THE SOUTHERN PART OF THE FORECAST AREA DURING THE EVENING. AN UPPER LEVEL WAVE WILL ALSO BE MOVING THROUGH THE AREA. EXPECT SOME THUNDERSTORMS ALONG THAT BOUNDARY DURING THE EVENING...BUT OVERNIGHT THEY SHOULD MOVE OUT OF THE AREA. MUCAPE IS THE HIGHEST DURING THE EARLY EVENING HOURS AND DIMINISHES SOME LATER IN THE EVENING...BUT STILL REMAINS AROUND 2500 J/KG. EXPECT THAT THERE COULD BE SOME SEVERE WEATHER DURING THE EVENING. A COOL SURFACE HIGH PRESSURE SYSTEM SETTLES INTO THE AREA ON WEDNESDAY. HIGH TEMPERATURES WILL BE AROUND 10 DEGREES COOLER THAN ON TUESDAY. WEDNESDAY SHOULD REMAIN DRY...BUT AN UPPER LEVEL WAVE MOVES ACROSS THE RIDGE AND THERE COULD BE SOME ISOLATED SHOWERS AND THUNDERSTORMS THAT MOVE OFF THE HIGH PLAINS DURING THE NIGHT TIME HOURS. THE SURFACE HIGH MOVES OFF TO THE EAST ON THURSDAY AND THE SURFACE PRESSURE GRADIENT TIGHTENS. WINDS AT 850MB ARE ONLY 20 TO 25 KTS SO EXPECT SOME BREEZY CONDITIONS. WITH WINDS FROM THE SOUTH THE TEMPERATURES WILL WARM UP. THE UPPER LEVEL RIDGE CONTINUES TO BUILD ACROSS THE AREA FOR THE PERIOD THURSDAY THROUGH SATURDAY. EXPECT TEMPERATURES TO WARM A LITTLE EACH DAY THROUGH THE PERIOD. THE UPPER LEVEL RIDGE REMAINS IN PLACE FOR SATURDAY NIGHT THROUGH MONDAY...BUT IT IS MORE OF AN UPPER LEVEL HIGH PRESSURE SYSTEM ACROSS THE AREA. IT IS FAIRLY BROAD AND THERE ARE A FEW UPPER LEVEL WAVES THAT MOVE THROUGH THE AREA. SIMILAR TO THE PAST WEEK OR SO EACH OF THESE UPPER LEVEL WAVES HAS A CHANCE FOR SOME THUNDERSTORMS. DO NOT EXPECT THAT IT WILL BE WIDESPREAD OR THAT EVERYONE WILL HAVE SOME PRECIPITATION. THE TIMING AND THE LOCATION OF ANY PRECIPITATION IS IN QUESTION. WITH A FEW MORE CLOUDS AND THE CHANCE FOR SOME PRECIPITATION THE TEMPERATURES WILL BE A LITTLE COOLER. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1255 AM CDT TUE JUL 9 2013 REST OF TNGT: VFR -RA/THUNDER LIKELY THRU 07Z THEN EXPECT DRY WX THEREAFTER. WINDS WILL BE VARIABLE AROUND PCPN. LLWS. MAYBE A TOUCH OF MVFR FOG NEAR DAYBREAK? TUE: VFR WITH SW WINDS 10 KTS OR LESS. WINDS MAY BECOME LGT AND VARIABLE 17-21Z. THEN COOL FRONT WILL SHIFT WINDS TO NW. THERE COULD BE SOME ISOLATED TSTM ACTIVITY NEARBY AFTER 21Z. TUE THRU 06Z: VFR. NW WINDS AROUND 10 KTS. && .GID WATCHES/WARNINGS/ADVISORIES... NE...HEAT ADVISORY FROM NOON TODAY TO 7 PM CDT THIS EVENING FOR NEZ085>087. KS...HEAT ADVISORY FROM NOON TODAY TO 7 PM CDT THIS EVENING FOR KSZ005>007-017>019. && $$ UPDATE...HALBLAUB SHORT TERM...PFANNKUCH LONG TERM...JCB AVIATION...HALBLAUB
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
424 AM EDT TUE JUL 9 2013 .SYNOPSIS... UNSETTLED WEATHER WILL CONTINUE INTO THURSDAY AS A SERIES OF DISTURBANCES COMBINE WITH A WARM MOIST AIRMASS OVER OUR AREA TO PRODUCE OCCASIONAL SHOWERS AND THUNDERSTORMS. DRYER AIR WILL FINALLY ARRIVE ON FRIDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... LATEST WATER VAPOR LOOP SHOWS A BAND OF MOISTURE PROGRESSING EASTWARD ACROSS NY AND PA THIS MORNING WITH A SMALL AREA OF DRYING JUST TO THE WEST... THEN ANOTHER WAVE OF MOISTURE MOVING EAST ACROSS THE WESTERN GREAT LAKES. EXPECT EACH OF THESE FEATURES TO AFFECT OUR AREA THROUGH LATE THIS AFTERNOON. CLOUDS AND SCATTERED LIGHT SHOWERS WILL OVERSPREAD THE AREA THIS MORNING... THEN EXPECT SOME CLEARING BY AFTERNOON FOLLOWED BY A ROUND OF SCATTERED THUNDERSTORMS INTO THIS EVENING. MODELS ALL INDICATE MODEST SYNOPTIC SCALE FORCING FOR ASCENT MOVING ACROSS THE AREA THIS AFTERNOON IN THE FORM OF A SFC-700 MB TROUGH AND WEAK WAA. THIS SHOULD RESULT IN A SLIGHTLY GREATER COVERAGE OF STORMS THIS AFTERNOON WITH POPS INCREASING TO AROUND 50 PCT. LATEST RAP FORECAST SOUNDINGS INDICATE MLCAPE VALUES INCREASING TO BETWEEN 800 AND 1000 J/KG BY LATE THIS AFTERNOON. WIND PROFILES APPEAR TO BE RATHER LIGHT WTIH ONLY 10 TO 20 KTS OF WIND EXTENDING UP THROUGH 500 MB. MODEST FORCING AND INSTABILITY ALONG WITH WEAK WIND SHEAR SHOULD RESULT IN MOSTLY PULSE TYPE STORMS THIS AFTERNOON WITH NOTHING MORE THAN AN ISOLATED... MARGINAL SEVERE THREAT. ANY STORM COULD ALSO CONTAIN HEAVY DOWMPOURS ONCE AGAIN AS PWAT VALUES APPROACH 2.00 INCHES... ALTHOUGH THE SHEAR DOES NOT APPEAR TO BE STRONG ENOUGH TO SUPPORT ORGANIZED LONG-LASTING STORMS. && .SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/... SHOWERS AND THUNDERSTORMS WILL DECREASE IN COVERAGE THIS EVENING WITH LOSS OF HEATING AND PASSAGE OF THE TROUGH TO THE EAST OF THE AREA. ANOTHER ROUND OF SHOWERS AND STORMS APPEARS LIKELY ON WEDNESDAY AS A COLD FRONT APPROACHES FROM THE WEST ALONG WITH MID- LEVEL HEIGHT FALLS OF 30 TO 50 M ASSOCIATED WITH AN UPPER TROUGH MOVING EAST ACROSS SOUTHERN CANADA. EXPECT MLCAPE VALUES TO ONCE AGAIN REACH NEAR 1000 J/KG ACROSS THE AREA WEDNESDAY AFTERNOON... AND THIS WILL BE ACCOMPANIED BY DEEP LAYER SHEAR INCREASING TO 20 TO 30 KTS WITH THE APPROACH OF THE UPPER LEVEL TROUGH. THIS SCENARIO WOULD LEAD TO A GREATER CHANCE OF SEVERE WEATHER WEDNESDAY AFTERNOON WITH SOME LINEAR ORGANIZATION OF THE CONVECTION ALONG A PRE-FRONTAL TROUGH POSSIBLY RESULTING IN STRONG DAMAING WINDS. BASED ON THESE FACTORS THE SPC DAY 2 CONVECTIVE OUTLOOK INDICATES A SLIGHT RISK OF SEVERE STORMS WEDNESDAY AFTERNOON EXTENDING FROM THE OHIO VALLEY ACROSS NY AND PA. MODEL CONSENSUS INDICATES THAT THE COLD FRONT WILL BE MOVING EAST OF OUR AREA ON THURSDAY WITH THE BEST CHC OF SHOWERS AND STORMS THURSDAY AFTERNOON EXTENDING FROM EASTERN NY INTO NEW ENGLAND. STILL A CHC OF SHOWERS AND STORMS WILL EXIST IN OUR AREA EXPECIALLY EAST OF I-81. SLIGHTLY COOLER AND DRYER AIR WILL FOLLOW BEHIND THIS FRONT THURSDAY NIGHT INTO FRIDAY. && .LONG TERM /FRIDAY THROUGH MONDAY/... 330 AM UPDATE...NO MAJOR CHANGES TO THE PREVIOUS FORECAST. STILL LOOKING LIKE WE MAY SEE AT LEAST A FEW DAYS OF DRY WEATHER STARTING FRIDAY...ESPECIALLY BASED ON THE NEW 0Z EURO. I DID MAINTAIN OUR GOING FORECAST OF SLIGHT TO LOW CHANCE (20 TO 30%) POPS THIS WEEKEND WITH THE GFS HINTING AT A DISTURBANCE ALOFT IN THE NORTHEAST DURING THIS TIME. THIS ALSO MATCHES UP WITH POP GUIDANCE FROM WPC. WITH THAT SAID BASED ON THE EURO AND SURFACE HIGH PRESSURE BUILDING IN...THE REALITY MAY BE A DRY WEEKEND. THE PREVIOUS AFD IS BELOW... STAGNANT PTRN CONTS TO MAKE FOR A TRICKY XTNDD PD. LATEST OPERATIONAL GFS RUN TRENDS TWRDS LAST NGT/S EURO WITH THU/S BRIEF RDGG GIVING WAY TO YET ANOTHER RETROGRADING OFF SHORE TROF. MASSIVE BERMUDA HI CONTS TO BLOCK THE EWRD PROGRESS OF NRN STREAM WV/S KEEPING THE NORTH BOUND TROPICAL FLOW IN PLACE ALONG THE CST NEAR TO OUR FCST AREA. FOR NOW...IT LOOKS LIKE THE MAJORITY OF THE MOISTURE ASSOCIATED WITH CHANTAL WELL EAST OF THE AREA...BUT WITH THE UNCERTAINTY...THIS DEEP MOISTURE WILL NEED TO BE MONITORED. DAILY SENSIBLE WX WILL SHOW SOME IMPRMNT ALTHOUGH THE ERN AND SRN AREA WILL CONT TO BE NEAR THE EDGE OF THE DEEP MOISTURE AND MORE AT RISK OF TRWS...ESP LATE IN THE PD. GNRLY FLWD HPC GUID BUT NUDGED THE DATA TWRD THE MEX AND NEARER TO THE SURROUNDING OFFICES. && .AVIATION /08Z TUESDAY THROUGH SATURDAY/... 06Z UPDATE... PERIODS OF FOG...PRODUCING IFR RESTRICTIONS ARE POSSIBLE THROUGH DAYBREAK ESPECIALLY AT KELM/KITH/KBGM WITH THESE SITES SEEING THE MOST RAIN MONDAY AFTERNOON. A COMPLICATING FACTOR WILL BE AN AREA OF HIGH CLOUDS NOW OVER WESTERN NY THAT WILL SLIDE EAST DURING THIS PERIOD. WITH IFR RESTRICTIONS ALREADY AT ALL THREE SITES BEING TEMPERED BY THIS HIGH CLOUD THREAT...ELECTED TO MAINLY GO WITH TEMPO GROUPS FOR IFR GIVEN THE HIGH VARIABILITY EXPECTED THROUGHOUT THE NIGHT. KELM STANDS THE BEST CHANCE FOR GOING DOWN AND STAYING DOWN. ELSEWHERE VFR IS EXPECTED. ANY FOG SHOULD BURN OFF BETWEEN 12Z AND 13Z. AFTER THAT A DISTURBANCE MOVING THROUGH LATER IN THE DAY WILL BRING SCT. SHOWERS TO THE TERMINALS MAINLY DURING THE PEAK HEATING (18Z - 0Z). WHILE THUNDER IS POSSIBLE I DID NOT INCLUDE IN THE TAFS JUST YET GIVEN THE EXPECTED SCT. COVERAGE. .OUTLOOK... WED THRU THU...PRIMARILY VFR BUT WITH RESTRICTIONS IN SCT SHWRS AND TRWS. IFR WITH OVRNGT VLY FOG PSBL. FRI/SAT...VFR WITH BRIEF IFR IN VLY FOG. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...MSE NEAR TERM...MSE SHORT TERM...MSE LONG TERM...DGM/HEDEN AVIATION...HEDEN
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1254 AM CDT TUE JUL 9 2013 .UPDATE... ISSUED AT 1254 AM CDT TUE JUL 9 2013 SEVERE TSTM WATCH 402 HAS EXPIRED...AND ALSO CANCELLED WATCH 403 FOR 4 COUNTIES IN NORTH CENTRAL NORTH DAKOTA. WATCH 403 REMAINS VALID UNTIL 4 AM CDT FOR A LINE FROM EMMONS TO WELLS COUNTIES AND EASTWARD. EXPECT TO BE ABLE TO DROP THESE COUNTIES IN THE NEXT HOUR OR 2 AS SEVERE LINE MOVES THROUGH. UPDATE ISSUED AT 1150 PM CDT MON JUL 8 2013 WILL LEAVE SEVERE T-STORM WATCH 403 AS IS FOR NOW. WILL EXTEND SVR WATCH 402 FOR MORTON...GRANT...AND SIOUX COUNTIES FOR ONE MORE HOUR WITH A LINE OF STORMS MOVING ACROSS THOSE COUNTIES RIGHT NOW. WHILE THE THREAT APPEARS LOW WITH THE BETTER SEVERE PARAMETERS IN SOUTH DAKOTA...FIGURE ONE MORE HOUR WILL NOT HURT...WHEN PERHAPS PART OF 403 CAN BE LET GO AS WELL. UPDATED PRODUCTS OUT SHORTLY. UPDATE ISSUED AT 1013 PM CDT MON JUL 8 2013 UPDATED THE FORECAST TO EXTEND THE SEVERE THUNDERSTORM WATCH EAST INTO THE JAMES RIVER VALLEY. MCS OVER WEST CENTRAL NORTH DAKOTA DEVELOPED INTO AN MCV IN THE LAST HOUR OR TWO. THE LEADING EDGE OF THIS ACTIVITY HAS BEEN PRODUCING WIDESPREAD WIND GUSTS UP TO 60 MPH. THIS ACTIVITY WILL CONTINUE TO PUSH EAST INTO THE JAMES RIVER VALLEY AFTER MIDNIGHT. ANOTHER BOW ECHO IS PUSHING EAST ACROSS SOUTHWESTERN NORTH DAKOTA. ITS STORM MOTION HAS BEEN EAST-SOUTHEAST AND WILL LIKELY CONTINUE TO PUSH INTO SOUTH DAKOTA DURING THE NEXT FEW HOURS. THE UPDATED PRODUCTS HAVE BEEN SENT. UPDATE ISSUED AT 703 PM CDT MON JUL 8 2013 UPDATED THE FORECAST TO ADD SEVERE THUNDERSTORM WATCH 402 FOR AREAS WEST OF HIGHWAY 83. ONGOING CONVECTION OVER EAST-CENTRAL MONTANA SHOULD CONTINUE TO MOVE EAST-SOUTHEAST INTO SOUTHWESTERN NORTH DAKOTA EARLY THIS EVENING. THIS ACTIVITY IS CONGEALING INTO AN MCS AND IS MOVING INTO A FAVORABLE ENVIRONMENT FOR MCS MAINTENANCE (SURFACE BASED CAPE AROUND 2000 J/KG PER LATEST LAPS ANALYSIS). THIS INITIAL CONVECTIVE ACTIVITY PROMPTED SPC TO ISSUE A SEVERE THUNDERSTORM WATCH FOR AREAS WEST OF HIGHWAY 83 UNTIL MIDNIGHT CDT. SHORT-RANGE MESOSCALE MODELS CONTINUE TO PROG THE PRIMARY LINE OF CONVECTION (CURRENTLY EXTENDING FROM GLASGOW TO BILLINGS) TO PUSH INTO WESTERN NORTH DAKOTA AROUND 03Z...AND SWEEP ACROSS THE CWA TONIGHT. THE FLY IN THE OINTMENT IS JUST HOW MUCH INSTABILITY THE INITIAL MCS CHEWS UP BEFORE THE PRIMARY LINE SWINGS THROUGH. STILL WILL MAINTAIN SEVERE WORDING PAST MIDNIGHT FOR CENTRAL NORTH DAKOTA. HOWEVER...WILL CONTINUE TO MONITOR EVENING TRENDS AND MAKE ANY ADJUSTMENTS AS NEEDED. THE UPDATED GRIDDED AND TEXT PRODUCTS HAVE BEEN SENT. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 341 PM CDT MON JUL 8 2013 THE MAIN FORECAST ISSUE DURING THE SHORT TERM IS STORM COVERAGE/TIMING/SEVERITY THROUGH TONIGHT. SCATTERED STORMS ARE EXPECTED TO DEVELOP AND/OR MOVE INTO THE WEST LATE THIS AFTERNOON. MORE FAVORABLE DEEP LAYER SHEAR IS CONFINED TO THE WEST THROUGH LATE AFTERNOON. SOME ISOLATED SEVERE STORMS ARE POSSIBLE...WITH LARGE HAIL THE MAIN THREAT. THE HRRR IS STILL FOCUSING ON THE SOUTHWEST FOR INITIATION...WHILE THE 12Z WRF FOCUSES ON A FRONT STRETCHING FROM WEST CENTRAL INTO NORTH CENTRAL NORTH DAKOTA. WILL CONTINUE TO MONITOR CLOSELY FOR INITIATION. AN INTENSE SUPERCELL IS MOVING THROUGH NORTHEAST MONTANA...AND WOULD IMPACT THE FORECAST AREA AFTER 00Z IF IT HOLDS TOGETHER. A BIGGER CONCERN WILL BE A THUNDERSTORM COMPLEX THAT WILL LIKELY TRACK FROM WEST TO EAST ACROSS THE FORECAST AREA AFTER AROUND 9 PM CDT. DAMAGING STRAIGHT LINE WINDS WILL BE THE BIGGEST THREAT. FAST STORM MOTIONS SHOULD PRECLUDE WIDESPREAD FLASH FLOODING. A MULTI- MEDIA WEATHER BRIEFING HAS BEEN POSTED AT WWW.WEATHER.GOV/BIS. THE SEVERE THREAT MAY PERSIST AFTER MIDNIGHT TONIGHT BEFORE STORMS WEAKEN. ADDITIONAL NON-SEVERE STORMS WILL BE LIKELY THROUGH AT LEAST MIDDAY TUESDAY. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 341 PM CDT MON JUL 8 2013 MAIN HIGHLIGHT FOR THE LONG TERM IS SHORTWAVE TROUGH AND ASSOCIATED COLD FRONT ENTERING NORTHERN PLAINS THURSDAY/FRIDAY. THE PERSISTENT HIGH AMPLITUDE RIDGING TO THE WEST WILL CONTINUE TO BE BOMBARDED BY SHORTWAVE TROUGHS DIVING DOWN OUT OF WESTERN CANADA. THIS WILL FORCE THE RIDGE TO TRANSLATE EASTWARD OVER THE CENTRAL STATES. THIS WILL IN TURN ALLOW NORTH DAKOTA TO BE INFLUENCED BY SOUTHWESTERLY FLOW AND LEE CYCLOGENESIS. BOTH THE 12 UTC ECMWF AND THE 12 UTC GFS BOTH HAVE A SHORTWAVE TROUGH DRAPED ACROSS THE NORTHERN PLAINS AND SURFACE LOW OVER NORTHWESTERN SOUTH DAKOTA EARLY FRIDAY MORNING. THIS WILL ALLOW FOR MOIST SOUTHERLY FLOW AHEAD OF THE COLD FRONT. WITH INCREASING MOISTURE...SURFACE LOW PRESSURE...AND UPPER LEVEL DIFFLUENCE WIDESPREAD THUNDERSTORM DEVELOPMENT IS POSSIBLE FRIDAY AFTERNOON AND EVENING. IN ADDITION TO THOSE INGREDIENTS THE 12 UTC ECMWF IS FORECASTING 50+ KNOTS OF 0-6 KM SHEAR...2000+ MUCAPE...AND DEW POINTS IN THE MID TO UPPER 60S. IF THIS VERIFIES...SEVERE WEATHER IS POSSIBLE FRIDAY AFTERNOON AND EVENING. OTHERWISE...THE EXTENDED PERIOD LOOKS ACTIVE WITH CHANCES FOR PRECIP THROUGHOUT THE PERIOD AS SHORTWAVES RIDE ALONG THE NORTHERN PERIPHERY OF THE RIDGE TO OUR SOUTH. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1254 AM CDT TUE JUL 9 2013 EXPECT THUNDERSTORMS AT KMOT/KBIS/KJMS TO CONTINUE THROUGH AROUND 09Z...WITH A POSSIBLE LINE GOING THROUGH KJMS AGAIN AFTER 09Z. KDIK MAY HAVE TSTMS LINGER THROUGH 07Z...BUT KISN SHOULD BE OUT OF THE MAIN LARGE AREA OF CONVECTION. MODELS HINTING AT MVFR CIGS DEVELOPING BY 09Z...THEN VFR BY 12Z/15Z. CIGS SCATTERING FROM WEST TO EAST AFT 18Z. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JV SHORT TERM...RPK LONG TERM...AJ AVIATION...JV
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1151 PM CDT MON JUL 8 2013 .UPDATE... ISSUED AT 1150 PM CDT MON JUL 8 2013 WILL LEAVE SEVERE T-STORM WATCH 403 AS IS FOR NOW. WILL EXTEND SVR WATCH 402 FOR MORTON...GRANT...AND SIOUX COUNTIES FOR ONE MORE HOUR WITH A LINE OF STORMS MOVING ACROSS THOSE COUNTIES RIGHT NOW. WHILE THE THREAT APPEARS LOW WITH THE BETTER SEVERE PARAMETERS IN SOUTH DAKOTA...FIGURE ONE MORE HOUR WILL NOT HURT...WHEN PERHAPS PART OF 403 CAN BE LET GO AS WELL. UPDATED PRODUCTS OUT SHORTLY. UPDATE ISSUED AT 1013 PM CDT MON JUL 8 2013 UPDATED THE FORECAST TO EXTEND THE SEVERE THUNDERSTORM WATCH EAST INTO THE JAMES RIVER VALLEY. MCS OVER WEST CENTRAL NORTH DAKOTA DEVELOPED INTO AN MCV IN THE LAST HOUR OR TWO. THE LEADING EDGE OF THIS ACTIVITY HAS BEEN PRODUCING WIDESPREAD WIND GUSTS UP TO 60 MPH. THIS ACTIVITY WILL CONTINUE TO PUSH EAST INTO THE JAMES RIVER VALLEY AFTER MIDNIGHT. ANOTHER BOW ECHO IS PUSHING EAST ACROSS SOUTHWESTERN NORTH DAKOTA. ITS STORM MOTION HAS BEEN EAST-SOUTHEAST AND WILL LIKELY CONTINUE TO PUSH INTO SOUTH DAKOTA DURING THE NEXT FEW HOURS. THE UPDATED PRODUCTS HAVE BEEN SENT. UPDATE ISSUED AT 703 PM CDT MON JUL 8 2013 UPDATED THE FORECAST TO ADD SEVERE THUNDERSTORM WATCH 402 FOR AREAS WEST OF HIGHWAY 83. ONGOING CONVECTION OVER EAST-CENTRAL MONTANA SHOULD CONTINUE TO MOVE EAST-SOUTHEAST INTO SOUTHWESTERN NORTH DAKOTA EARLY THIS EVENING. THIS ACTIVITY IS CONGEALING INTO AN MCS AND IS MOVING INTO A FAVORABLE ENVIRONMENT FOR MCS MAINTENANCE (SURFACE BASED CAPE AROUND 2000 J/KG PER LATEST LAPS ANALYSIS). THIS INITIAL CONVECTIVE ACTIVITY PROMPTED SPC TO ISSUE A SEVERE THUNDERSTORM WATCH FOR AREAS WEST OF HIGHWAY 83 UNTIL MIDNIGHT CDT. SHORT-RANGE MESOSCALE MODELS CONTINUE TO PROG THE PRIMARY LINE OF CONVECTION (CURRENTLY EXTENDING FROM GLASGOW TO BILLINGS) TO PUSH INTO WESTERN NORTH DAKOTA AROUND 03Z...AND SWEEP ACROSS THE CWA TONIGHT. THE FLY IN THE OINTMENT IS JUST HOW MUCH INSTABILITY THE INITIAL MCS CHEWS UP BEFORE THE PRIMARY LINE SWINGS THROUGH. STILL WILL MAINTAIN SEVERE WORDING PAST MIDNIGHT FOR CENTRAL NORTH DAKOTA. HOWEVER...WILL CONTINUE TO MONITOR EVENING TRENDS AND MAKE ANY ADJUSTMENTS AS NEEDED. THE UPDATED GRIDDED AND TEXT PRODUCTS HAVE BEEN SENT. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 341 PM CDT MON JUL 8 2013 THE MAIN FORECAST ISSUE DURING THE SHORT TERM IS STORM COVERAGE/TIMING/SEVERITY THROUGH TONIGHT. SCATTERED STORMS ARE EXPECTED TO DEVELOP AND/OR MOVE INTO THE WEST LATE THIS AFTERNOON. MORE FAVORABLE DEEP LAYER SHEAR IS CONFINED TO THE WEST THROUGH LATE AFTERNOON. SOME ISOLATED SEVERE STORMS ARE POSSIBLE...WITH LARGE HAIL THE MAIN THREAT. THE HRRR IS STILL FOCUSING ON THE SOUTHWEST FOR INITIATION...WHILE THE 12Z WRF FOCUSES ON A FRONT STRETCHING FROM WEST CENTRAL INTO NORTH CENTRAL NORTH DAKOTA. WILL CONTINUE TO MONITOR CLOSELY FOR INITIATION. AN INTENSE SUPERCELL IS MOVING THROUGH NORTHEAST MONTANA...AND WOULD IMPACT THE FORECAST AREA AFTER 00Z IF IT HOLDS TOGETHER. A BIGGER CONCERN WILL BE A THUNDERSTORM COMPLEX THAT WILL LIKELY TRACK FROM WEST TO EAST ACROSS THE FORECAST AREA AFTER AROUND 9 PM CDT. DAMAGING STRAIGHT LINE WINDS WILL BE THE BIGGEST THREAT. FAST STORM MOTIONS SHOULD PRECLUDE WIDESPREAD FLASH FLOODING. A MULTI- MEDIA WEATHER BRIEFING HAS BEEN POSTED AT WWW.WEATHER.GOV/BIS. THE SEVERE THREAT MAY PERSIST AFTER MIDNIGHT TONIGHT BEFORE STORMS WEAKEN. ADDITIONAL NON-SEVERE STORMS WILL BE LIKELY THROUGH AT LEAST MIDDAY TUESDAY. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 341 PM CDT MON JUL 8 2013 MAIN HIGHLIGHT FOR THE LONG TERM IS SHORTWAVE TROUGH AND ASSOCIATED COLD FRONT ENTERING NORTHERN PLAINS THURSDAY/FRIDAY. THE PERSISTENT HIGH AMPLITUDE RIDGING TO THE WEST WILL CONTINUE TO BE BOMBARDED BY SHORTWAVE TROUGHS DIVING DOWN OUT OF WESTERN CANADA. THIS WILL FORCE THE RIDGE TO TRANSLATE EASTWARD OVER THE CENTRAL STATES. THIS WILL IN TURN ALLOW NORTH DAKOTA TO BE INFLUENCED BY SOUTHWESTERLY FLOW AND LEE CYCLOGENESIS. BOTH THE 12 UTC ECMWF AND THE 12 UTC GFS BOTH HAVE A SHORTWAVE TROUGH DRAPED ACROSS THE NORTHERN PLAINS AND SURFACE LOW OVER NORTHWESTERN SOUTH DAKOTA EARLY FRIDAY MORNING. THIS WILL ALLOW FOR MOIST SOUTHERLY FLOW AHEAD OF THE COLD FRONT. WITH INCREASING MOISTURE...SURFACE LOW PRESSURE...AND UPPER LEVEL DIFFLUENCE WIDESPREAD THUNDERSTORM DEVELOPMENT IS POSSIBLE FRIDAY AFTERNOON AND EVENING. IN ADDITION TO THOSE INGREDIENTS THE 12 UTC ECMWF IS FORECASTING 50+ KNOTS OF 0-6 KM SHEAR...2000+ MUCAPE...AND DEW POINTS IN THE MID TO UPPER 60S. IF THIS VERIFIES...SEVERE WEATHER IS POSSIBLE FRIDAY AFTERNOON AND EVENING. OTHERWISE...THE EXTENDED PERIOD LOOKS ACTIVE WITH CHANCES FOR PRECIP THROUGHOUT THE PERIOD AS SHORTWAVES RIDE ALONG THE NORTHERN PERIPHERY OF THE RIDGE TO OUR SOUTH. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING) ISSUED AT 703 PM CDT MON JUL 8 2013 THE MAIN FOCUS THROUGH THE TAF PERIOD IS THUNDERSTORMS. OTHERWISE...EXPECT VFR CONDITIONS. SCATTERED STORMS ARE EXPECTED THIS EVENING...BUT TOUGH TO PINPOINT FAVORED AREA FOR DEVELOPMENT AND TIMING. LATER TONIGHT...AFTER 02Z...ENHANCED WINDS WILL BE POSSIBLE WITH FAST MOVING LINES OF THUNDERSTORMS. ALTHOUGH THESE SEVERE WEATHER ELEMENTS WILL BE POSSIBLE..TOO UNCERTAIN IN TIMING TO INCLUDE IN TAF FORECAST. AVIATION PLANNERS SHOULD ANTICIPATE MULTIPLE LINES OF THUNDERSTORMS MOVING WEST TO EAST ACROSS THE STATE AFTER 02Z. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...NH SHORT TERM...RPK LONG TERM...AJ AVIATION...TM
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
417 AM EDT TUE JUL 9 2013 .SYNOPSIS... THE WEATHER WILL REMAIN UNSETTLED ACROSS THE LOWER GREAT LAKES AND OHIO VALLEY TODAY AND TONIGHT AHEAD OF A COLD FRONT THAT WILL MOVE THROUGH THE AREA ON WEDNESDAY. THURSDAY AND FRIDAY HIGH PRESSURE AND DRY STABLE AIR WILL BUILD IN. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... MADE ADJUSTMENT TO THE FLOOD WATCH TRIMMING THE NORTHERN COUNTIES BUT EXTENDING IT A FEW HOURS INTO THE MORNING FOR THE REMAINING SOUTHERN COUNTIES. RADAR SHOWS THE HEAVY RAIN MOVING SLOWLY EAST HOWEVER MORE SHOWERS HAVE DEVELOPED ON THE WEST SIDE OF THE MAIN CONVECTION ACROSS PORTIONS OF CRAWFORD/WYANDOT AND MARION COUNTIES. RAIN STILL OCCURRING ACROSS THE CENTRAL LAKESHORE BUT IS NOT INTENSE ENOUGH TO CAUSE FLOODING. FOR THE MORNING EXPECT THE TREND IN PLACE TO SLOWLY CONTINUE WITH PRECIP MOVING EAST/SOUTHEAST OF THE AREA AND DRIER AIR MOVING IN FROM THE NORTHWEST. SHOULD EVENTUALLY SEE SOME SS TODAY HOWEVER HRRR DOES SHOW SCATTERED CONVECTION REDEVELOPING IN THE MOIST UNSTABLE AIR STILL IN PLACE ACROSS THE AREA LATER THIS AFTERNOON. BEST CHANCES WOULD BE WEST/SWRN COUNTIES. WILL BRING CHANCE POPS BACK TO THE SRN/SWRN COUNTIES WITH SLIGHT CHANCE POPS ON THE NORTH SIDE OF THAT. HIGHS NEAR GUIDANCE. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/... FOLLOWED MIX OF HPC/NAM AND SREF GUIDANCE FOR THE SHORT TERM. COLD FRONT IS ON THE WAY FOR WEDNESDAY AND TONIGHT AHEAD OF THE FRONT MODELS SHOWED A COUPLE SHORT WAVES MOVING ACROSS THE REGION. EXPECTING SHOWERS/THUNDERSTORMS MOVING IN FROM THE WEST LATE EVENING OR EARLY IN THE NIGHT AND PERSISTING THROUGH MUCH OF WEDNESDAY. WOULD ANTICIPATE THE NEED FOR A FLOOD WATCH BUT GIVEN THE CURRENT HEADLINE WILL WAIT FOR DAY SHIFT TO REEVALUATE. GIVEN HPC QPF VALUES INCREASED MAV GUIDANCE POPS AGREEING MORE WITH THE SREF CATEGORICAL GUIDANCE TONIGHT AND WEDNESDAY. THURSDAY AND FRIDAY SUN AND DRY. && .LONG TERM /SATURDAY THROUGH MONDAY/... MODELS HAVE BEEN SLOWLY TRENDING TO A DRIER WEEKEND WITH THE CENTRAL U.S. RIDGE TRYING TO NOSE INTO THE LOWER GREAT LAKES AND THE TROUGH SHIFTING TO THE EAST COAST. THIS WILL PUT IS IN THE MIDDLE AND WILL KEEP THE DRY WEEKEND FORECAST AND THE LOW PRECIP CHANCES FOR MONDAY WITH AN INCREASE IN MOISTURE. WILL PUT TEMPS IN BETWEEN GFS AND ECMWF GUIDANCE AS A COMPROMISE SEEMS BEST RIGHT NOW. THAT WILL GIVE US SEASONABLE TEMPS FOR THE WEEKEND IN THE LOWER TO MID 80S. && .AVIATION /08Z TUESDAY THROUGH SATURDAY/... SCATTERED SHOWERS AND THUNDERSTORMS REMAIN FOR THE REMAINDER OF THE NIGHT. IFR WITHIN THESE SHRA/TS. SOME AREAS OF MVFR AS WELL. BIGGEST TASK IS WHETHER NON VFR CEILINGS OF VSBYS WILL DEVELOP IN A MORE WIDESPREAD NATURE. LATEST SREF BRINGS IN MVFR AND SOME IFR ACROSS SOUTHERN MI ACROSS ONTARIO AND INTO NW PA. HAVE LEANED THIS WAY AND HAVE BROUGHT THE LOWEST CONDITIONS INTO TOLEDO. WITH DOWNSLOPE FLOW DID NOT GO TOO LOW AT ERIE. EVEN THOUGH THERE IS PLENTY OF LOW LEVEL MOISTURE...LIGHT WIND AND CURRENT CIGS SHOULD PREVENT VSBY FROM GETTING TOO LOW. START MOST AT MVFR IN MID MORNING...IMPROVING TO VFR. MOST OF THE SHOWERS LOOK TO BE OVER BY AROUND 12Z...BUT AREA MAY GET NEW DEVELOPMENT AGAIN TOWARD YNG/CAK LATE THIS AFTERNOON. UNSURE ABOUT FDY/MFD. AGAIN THIS IS FOCUSING ON THE TIMES WITH THE BEST CHANCES...STILL COULD SEE A SHRA/TS AT JUST ABOUT ANY TIME. .OUTLOOK...NON-VFR EXPECTED IN SHOWERS AND THUNDERSTORMS THROUGH WEDNESDAY NIGHT. && .MARINE... A RELATIVE LULL IN THE THUNDERSTORM CHANCES FOR TODAY. SOUTH-SW FLOW WILL CONTINUE WITH A NEARLY STATIONARY BOUNDARY JUST NORTH OF THE LAKE. LOW PRESSURE WILL TRACK ACROSS THE NORTHERN LAKES WEDNESDAY AND TAKE A COLD FRONT ACROSS LAKE ERIE WITH ANOTHER ROUND OF THUNDERSTORMS...SOME OF WHICH WILL BE ON THE STRONG SIDE. WINDS MAY PICK UP ENOUGH TO NEED A SMALL CRAFT ADV WITH THIS SYSTEM. SOME CHOP POSSIBLE WEDNESDAY AHEAD OF THE FRONT FOR THE EASTERN NEARSHORE WITH SW FLOW ALONG THE LENGTH OF THE LAKE. BETTER CHANCES FOR SMALL CRAFT ADV CONDITIONS IN THE NORTHWEST FLOW AFTER THE FRONT. THE WEATHER SETTLES DOWN THURSDAY THROUGH SATURDAY WITH HIGH PRESSURE OVER THE CENTRAL GREAT LAKES. WILL HAVE A NORTHERLY FLOW THAT WILL BECOME ENE BY SATURDAY AS THE HIGH SHIFTS EAST...REMAINING NORTH OF LAKE ERIE. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...FLASH FLOOD WATCH UNTIL 9 AM EDT THIS MORNING FOR OHZ027>030- 036-037-047. PA...NONE. MARINE...NONE. && $$ SYNOPSIS...TK NEAR TERM...TK SHORT TERM...TK/KOSARIK LONG TERM...OUDEMAN AVIATION...OUDEMAN MARINE...OUDEMAN
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
413 AM EDT TUE JUL 9 2013 .SYNOPSIS... AN UNSETTLED WEATHER PATTERN WILL CONTINUE THROUGH WEDNESDAY NIGHT. A COLD FRONT WILL CROSS THE REGION LATE WEDNESDAY NIGHT. HIGH PRESSURE BEHIND THE FRONT WILL BRING DRIER WEATHER TO THE AREA THAT WILL LAST INTO THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... A DISTURBANCE MOVING EAST OUT OF CENTRAL OHIO THIS MORNING WILL TAKE WITH IT THE STRONG MOISTURE TRANSPORT AND HEAVIER SHOWERS AND THUNDERSTORMS. IN ITS WAKE...SCATTERED SHOWERS WILL BE POSSIBLE THROUGH THE MORNING HOURS. ANOTHER DISTURBANCE UPSTREAM OF THE AREA WILL HELP TO TRIGGER ADDITIONAL SHOWERS AND THUNDERSTORMS THIS AFTERNOON. A BOUNDARY ACROSS THE OHIO RIVER THIS MORNING WILL LIFT NORTH JUST AHEAD OF THIS DISTURBANCE AND SHOULD BE THE FOCUS OF WHERE CONVECTION INITIATES THIS AFTERNOON. THERE ARE SUBTLE DIFFERENCES IN WHERE THIS LOCATION WILL BE. FAVORED THE ARW FOR THE INITIAL CONVECTION DEVELOPMENT ALONG AND NORTH OF THE INTERSTATE 70 CORRIDOR...GRADUALLY SHIFTING SOUTH AND EAST IN FOCUS TOWARD THE EVENING. CLOUD COVER MAY PREVENT TEMPERATURES FROM RISING INTO THE UPPER 80S THIS AFTERNOON. AS SUCH...WENT WITH THE MIDDLE 80S FOR MOST OF OUR ZONES. WILL KEEP THE FLASH FLOOD WATCH UP UNTIL 10 AM FOR OUR EXTREME NORTHEASTERN ZONES...NEARER TO THE DEPARTING CONVECTION. HAVE REMOVED THOSE COUNTIES THAT HAVE NOT SEEN MUCH IN THE WAY OF HEAVY RAIN...AND WILL LIKELY NOT SEE MUCH MORE RAIN BEFORE THE WATCH EXPIRES. THIS AFTERNOON...REDEVELOPING CONVECTION COULD ONCE AGAIN POSE A FLOODING THREAT. WILL HIGHLIGHT THIS THREAT IN THE HWO FOR NOW. && .SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/... SIMILAR TO PREVIOUS NIGHTS...IN THIS VERY MOIST AIRMASS AND WITH A PASSING DISTURBANCE IN THE AREA...CONVECTION WILL PROBABLY BE ONGOING AS WE HEAD INTO TONIGHT`S TIME PERIOD. THE EVENING CONVECTION IS EXPECTED TO BE SHIFTING TOWARD THE SOUTH AND EAST IN THE NORTHWESTERLY FLOW ALOFT TO START TONIGHT. UPSTREAM...A DEVELOPING NOCTURNAL LOW LEVEL JET IS EXPECTED TO ENHANCE CONVECTION AFTER SUNSET. THIS CONVECTION WILL PERSIST ACROSS PORTIONS OF OUR AREA OVERNIGHT. THERE IS UNCERTAINTY AS TO WHERE EXACTLY THESE STORMS WILL OCCUR. THEREFORE...COULD NOT LEAN THE POPS ONE WAY OR ANOTHER GEOGRAPHICALLY IN THE FORECAST AREA DURING THIS PACKAGE ISSUANCE. REGARDLESS...ANY CONVECTION THAT DOES OCCUR COULD STILL POSE A FLOOD THREAT...IN ADDITION TO ISOLATED HAIL AND DAMAGING WINDS SHOULD STORMS BECOME INTENSE. TONIGHT`S SEVERE PROBABILITY APPEARS LOW AT THIS TIME. THEREFORE WILL ONLY HIGHLIGHT THE FLOODING THREAT IN THE HWO FOR THIS TIME PERIOD. A COLD FRONT WILL APPROACH THE REGION ON WEDNESDAY. THIS WILL HELP TO INCREASE SHEAR ACROSS OUR AREA AND ENHANCE THUNDERSTORM DEVELOPMENT. ALTHOUGH 0-6 KM SHEAR WILL ONLY BE AROUND 30 KT...THIS WOULD BE SUFFICIENT FOR SOME SEVERE STORMS TO DEVELOP. IF THIS DOES OCCUR...THE MAIN THREAT FROM THESE STORMS WILL BE DAMAGING WINDS AND LARGE HAIL. THIS SEVERE THREAT WILL BE HIGHLIGHTED IN THE HWO FOR THE WEDNESDAY INTO WEDNESDAY NIGHT TIME PERIOD. BY LATE WEDNESDAY NIGHT...CONVECTION WILL SHIFT SOUTHEAST OF OUR AREA AHEAD OF A COLD FRONT. HIGH PRESSURE WILL BUILD EASTWARD ACROSS OUR REGION ON THURSDAY...BRINGING TO THE AREA A DRIER AND MORE STABLE AIRMASS. EXPECT FAIR CONDITIONS BOTH THURSDAY AND THURSDAY NIGHT. TEMPERATURES THURSDAY WILL BE IN THE LOW 80S. EXPECT SEASONABLY COOL LOWER 60S THURSDAY NIGHT. && .LONG TERM /FRIDAY THROUGH MONDAY/... REGION WILL FIND ITSELF SPLIT BY A CDFNT AT THE BEGINNING OF THE PERIOD. THE FRONT WILL BE LOCATED NEAR THE OHIO RIVER AT 12Z THURSDAY. MODELS QUICKLY PUSH THE FRONT INTO THE APPALACHIANS AND REPLACE IT WITH HIGH PRESSURE. THIS SHOULD MEAN SOME LINGERING CONVECTION FOR THE MORNING HOURS OF THURSDAY IN THE EXTREME SOUTH...WITH DRY CONDITIONS FOR THE N. MODELS DROP AN H5 S/W INTO LAKE ERIE THURSDAY AFTN...BUT RIGHT NOW IT APPEARS THAT THE S/W WILL PRODUCE JUST SOME AFTN CLOUDS AND NOT ANY AFTN SHOWERS. HIGH PRESSURE WILL BUILD IN THURSDAY NIGHT AND WILL HOLD CONTROL INTO SATURDAY NIGHT. THIS SHOULD ALLOW THE REGION TO BEGIN TO DRY OUT. RETURN FLOW BY SUNDAY WILL BRING THE RETURN OF SCT CONVECTION FOR SUNDAY AND MONDAY. WENT WITH LOW CHC POPS FOR NOW. HIGHS THURSDAY INTO SATURDAY WILL BE A FEW DEGREES EITHER SIDE OF 80 FOR THE REGION. BY SUNDAY AND MONDAY...HIGHS WILL RISE INTO THE LOWER 80S. LOWS WILL BE IN THE LOWER 60S FOR THE FIRST HALF OF THE PERIOD...THEN THE MID 60S FOR THE LATER HALF. && .AVIATION /08Z TUESDAY THROUGH SATURDAY/... SHOWERS AND THUNDERSTORMS ARE CONTINUING TO SAG SOUTHEAST ACROSS CENTRAL OHIO. THERE DOES APPEAR TO BE SOMEWHAT OF A BACK EDGE TO IT THOUGH WITH JUST SOME VERY SPOTTY SHOWERS FARTHER BACK TO THE NORTHWEST. THE LATEST RUC AND HRR ARE BOTH SUGGESTING SOME ADDITIONAL REDEVELOPMENT ACROSS CENTRAL OHIO THROUGH DAYBREAK. THE 00Z ARW IS ALSO SUGGESTING SOME REGENERATION...BUT KEEPING IT NORTH OF THE TAF SITES. AS A RESULT...KCMH/KLCK MAY REMAIN ALONG OR NEAR THE EDGE OF THIS THROUGH DAYBREAK. MEANWHILE...SHOWERS ARE POPPING UP ACROSS SOUTHERN INDIANA AND THE GLOBAL MODELS ARE INDICATING SOME OF THESE WILL SAG DOWN TOWARD KCVG/KLUK THROUGH DAYBREAK. QUITE A BIT OF MODEL VARIANCE AS TO WHAT WILL OCCUR LATER TODAY INTO TONIGHT. WILL TRY TO ALLOW FOR A LULL IN THE PCPN FROM LATE MORNING INTO EARLY AFTERNOON...BUT CONFIDENCE IN THIS IS NOT VERY HIGH AS SOME OF THE HI RES MODELS ARE HINTING AT PCPN LINGERING THROUGH MUCH OF THE DAY...ESPECIALLY ACROSS OUR NORTH. HOWEVER...THINK BETTER CHANCE FOR THUNDERSTORMS WILL BE LATER IN THE DAY AS WE DESTABILIZE THROUGH THE AFTERNOON. THINK BEST CHANCE FOR REDEVELOP MET WILL BE ALONG A REMNANT BOUNDARY THAT WILL LIKELY BE ALONG THE I 70 CORRIDOR BY LATE AFTERNOON...WITH PCPN THEN SAGGING SOUTH TOWARD THE OHIO RIVER THROUGH THE EVENING. OUTLOOK...GOOD CHANCE OF THUNDERSTORMS WEDNESDAY AND WEDNESDAY NIGHT. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...FLASH FLOOD WATCH UNTIL 10 AM EDT THIS MORNING FOR OHZ026-034- 035-042>046-051>056-060>065-073-074. KY...NONE. IN...FLASH FLOOD WATCH UNTIL 10 AM EDT THIS MORNING FOR INZ050-058- 059. && $$ SYNOPSIS...LATTO NEAR TERM...LATTO SHORT TERM...LATTO LONG TERM...SITES AVIATION...JGL
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
135 AM EDT TUE JUL 9 2013 .SYNOPSIS... A SERIES OF UPPER LEVEL DISTURBANCES WILL RESULT IN A CONTINUED CHANCE OF THUNDERSTORMS THROUGH MID WEEK. A COLD FRONT WILL PUSH THROUGH THE AREA WEDNESDAY NIGHT. BUILDING HIGH PRESSURE IN THE UPPER MIDWEST BEHIND THE FRONT WILL BRING DRIER CONDITIONS FOR THE REMAINDER OF THE WEEK. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... HAVE BECOME INCREASINGLY CONCERNED ABOUT HEAVY RAIN/FLASH FLOOD POTENTIAL FOR THE OVERNIGHT HOURS ACROSS THE NORTHERN HALF OF THE FORECAST AREA. MODELS ARE SHOWING A LOW LEVEL JET ACROSS NORTHERN OHIO THAT KEEPS AN AXIS OF MOISTURE TRANSPORT ACROSS THE REGION THROUGH THE NIGHT. GUIDANCE HAS BEEN DEVELOPING AN EAST-WEST LINE OF PRECIPITATION WHICH ONCE IT SETS UP MAY NOT MOVE MUCH AS IT BECOMES PARALLEL TO THE 0-3 KM SHEAR VECTOR. ALTHOUGH IT SHOULD BE NOTED THAT SOME RECENT RUNS OF THE HRRR AND RAP SUGGEST THAT THE CONVECTIVE LINE MAY BE ABLE TO SAG SOUTH. ALSO THE WARM CLOUD DEPTH IS DEEP WHICH WILL MAKE FOR VERY EFFICIENT RAINFALL PRODUCTION. SOME OF THE REGION ALREADY HAD HEAVY RAINFALL EARLY MONDAY MORNING WHICH SATURATED THE GROUND. ALL OF THIS SUGGESTS THAT THERE IS A SUBSTANTIAL THREAT OF FLASH FLOODING AND IT IS POSSIBLE THAT SOME LOCATIONS COULD SEE SIGNIFICANT IMPACTS OVERNIGHT. THUS HAVE EXPANDED THE FLASH FLOOD WATCH BACK WEST TO INCLUDE MOST OF THE MIAMI VALLEY AND PARTS OF THE WHITEWATER VALLEY. && .SHORT TERM /6 AM THIS MORNING THROUGH WEDNESDAY NIGHT/... MODELS ARE IN DISAGREEMENT WITH THE EVOLUTION OF THE RAIN FROM TONIGHT. CANNOT REMOVE A CHANCE FOR THUNDERSTORMS IN AN AIRMASS THAT HAS BEEN EXTREMELY SUPPORTIVE OF THEM FOR THE PAST WEEK OR MORE. HEAVY RAIN WILL BE A POSSIBILITY WITH ANY OF THESE STORMS...AND THE CHANCES WILL REALLY INCREASE LATE WEDNESDAY AND OVERNIGHT AS A DISTINCT COLD FRONT WITH UPPER LEVEL SUPPORT CROSSES THE AREA. UNTIL THIS TIME...MORE OF THE SAME IS EXPECTED AND HIGHS WILL GRADUALLY CREEP UPWARDS A DEGREE OR TWO EACH DAY. NIGHTTIME LOWS WILL ONLY BE MITIGATED TO BE COOLER FROM STORMS THAT MAY OR MAY NOT BE PRESENT AT TIMES...AT LEAST TUESDAY NIGHT. OUTSIDE OF THE STORMS...THE AIRMASS WILL RETAIN HIGH DEWPOINTS AND LIMIT NIGHTTIME DROPOFFS MUCH BELOW 70 DEGREES. && .LONG TERM /THURSDAY THROUGH MONDAY/... REGION WILL FIND ITSELF SPLIT BY A CDFNT AT THE BEGINNING OF THE PERIOD. THE FRONT WILL BE LOCATED NEAR THE OHIO RIVER AT 12Z THURSDAY. MODELS QUICKLY PUSH THE FRONT INTO THE APPALACHIANS AND REPLACE IT WITH HIGH PRESSURE. THIS SHOULD MEAN SOME LINGERING CONVECTION FOR THE MORNING HOURS OF THURSDAY IN THE EXTREME SOUTH...WITH DRY CONDITIONS FOR THE N. MODELS DROP AN H5 S/W INTO LAKE ERIE THURSDAY AFTN...BUT RIGHT NOW IT APPEARS THAT THE S/W WILL PRODUCE JUST SOME AFTN CLOUDS AND NOT ANY AFTN SHOWERS. HIGH PRESSURE WILL BUILD IN THURSDAY NIGHT AND WILL HOLD CONTROL INTO SATURDAY NIGHT. THIS SHOULD ALLOW THE REGION TO BEGIN TO DRY OUT. RETURN FLOW BY SUNDAY WILL BRING THE RETURN OF SCT CONVECTION FOR SUNDAY AND MONDAY. WENT WITH LOW CHC POPS FOR NOW. HIGHS THURSDAY INTO SATURDAY WILL BE A FEW DEGREES EITHER SIDE OF 80 FOR THE REGION. BY SUNDAY AND MONDAY...HIGHS WILL RISE INTO THE LOWER 80S. LOWS WILL BE IN THE LOWER 60S FOR THE FIRST HALF OF THE PERIOD...THEN THE MID 60S FOR THE LATER HALF. && .AVIATION /05Z TUESDAY THROUGH SATURDAY/... SHOWERS AND THUNDERSTORMS ARE CONTINUING TO SAG SOUTHEAST ACROSS CENTRAL OHIO. THERE DOES APPEAR TO BE SOMEWHAT OF A BACK EDGE TO IT THOUGH WITH JUST SOME VERY SPOTTY SHOWERS FARTHER BACK TO THE NORTHWEST. THE LATEST RUC AND HRR ARE BOTH SUGGESTING SOME ADDITIONAL REDEVELOPMENT ACROSS CENTRAL OHIO THROUGH DAYBREAK. THE 00Z ARW IS ALSO SUGGESTING SOME REGENERATION...BUT KEEPING IT NORTH OF THE TAF SITES. AS A RESULT...KCMH/KLCK MAY REMAIN ALONG OR NEAR THE EDGE OF THIS THROUGH DAYBREAK. MEANWHILE...SHOWERS ARE POPPING UP ACROSS SOUTHERN INDIANA AND THE GLOBAL MODELS ARE INDICATING SOME OF THESE WILL SAG DOWN TOWARD KCVG/KLUK THROUGH DAYBREAK. QUITE A BIT OF MODEL VARIANCE AS TO WHAT WILL OCCUR LATER TODAY INTO TONIGHT. WILL TRY TO ALLOW FOR A LULL IN THE PCPN FROM LATE MORNING INTO EARLY AFTERNOON...BUT CONFIDENCE IN THIS IS NOT VERY HIGH AS SOME OF THE HI RES MODELS ARE HINTING AT PCPN LINGERING THROUGH MUCH OF THE DAY...ESPECIALLY ACROSS OUR NORTH. HOWEVER...THINK BETTER CHANCE FOR THUNDERSTORMS WILL BE LATER IN THE DAY AS WE DESTABILIZE THROUGH THE AFTERNOON. THINK BEST CHANCE FOR REDEVELOP MET WILL BE ALONG A REMNANT BOUNDARY THAT WILL LIKELY BE ALONG THE I 70 CORRIDOR BY LATE AFTERNOON...WITH PCPN THEN SAGGING SOUTH TOWARD THE OHIO RIVER THROUGH THE EVENING. OUTLOOK...GOOD CHANCE OF THUNDERSTORMS WEDNESDAY AND WEDNESDAY NIGHT. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...FLASH FLOOD WATCH UNTIL 10 AM EDT THIS MORNING FOR OHZ026-034- 035-042>046-051>056-060>065-073-074. KY...NONE. IN...FLASH FLOOD WATCH UNTIL 10 AM EDT THIS MORNING FOR INZ050-058- 059. && $$ SYNOPSIS...FRANKS NEAR TERM... SHORT TERM...FRANKS LONG TERM...SITES AVIATION...JGL
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
439 AM EDT TUE JUL 9 2013 .SYNOPSIS... A BERMUDA HIGH ANCHORED OFF THE EASTERN SEABOARD WILL CONTINUE TO FEED VERY WARM AND HUMID AIR NORTHWARD INTO THE COMMONWEALTH. DAILY CHANCES OF SHOWERS AND THUNDERSTORMS WILL PERSIST UNTIL A COLD FRONT PASSES THURSDAY. && .NEAR TERM /UNTIL 4 PM THIS AFTERNOON/... BROAD SHORT WAVE TROUGH WHICH SEEMS UNDERDONE BY THE MDLS IS DROPPING ESE FROM OHIO EARLY THIS MORNING. MID LEVEL WINDS INCREASE FROM THE SW SLIGHTLY THIS MORNING...AND MOISTURE POOLING AT THE AXIS OF THE TROUGH WILL SLIDE ACROSS THE CWA FROM W-E AS MAINLY LIGHT SHOWERS AND WIDELY SCT/EMBEDDED THUNDER. HEAVIER RAIN ON A TRACK TO MOVE TO THE SOUTH OF THE AREA. HRRR SEEMS TO HAVE A GOOD HANDLE ON RECENT TRENDS. IT PORTRAYS THE DEATH OF MUCH OF THIS FIRST BATCH OF LIGHT RAIN AS IT MOVES TO THE EAST...THEN A RE-DEVELOPMENT OF CONVECTION AS DAYTIME HEATING COMBINES WITH BREAKS IN THE CLOUD COVER TO BUBBLE UP SHRA/TSRA. WITH CLOUDS AND SCT/NMRS SHOWERS AROUND...WILL KEEP MAXE TEMPS LOOKING LIKE YESTERDAY/MON. DEWPOINTS ALSO MOVE LITTLE SO ANOTHER SEASONAL JULY DAY IS IN STORE. && .SHORT TERM /4 PM THIS AFTERNOON THROUGH 6 PM WEDNESDAY/... THE SHORT WAVE PUSHES TO THE EAST THIS EVENING AND A DECREASE IN SHRA/TSRA IS EXPECTED FOR MOST OF THE OVERNIGHT HOURS. WILL JUST LEAVE IN SCT/ISOLD WORDING FOR NOW. HEIGHTS DROP THROUGH THE NIGHT...THOUGH. THIS OCCURS AS A BROADER AND MORE-SYNOPTIC SCALE TROUGH AXIS NEARS FROM THE GREAT LAKES/UPPER MIDWEST. THE MOISTURE PLUME PUSHES RIGHT BACK INTO THE AREA LATE TONIGHT AND HANGS OUT OVERHEAD THROUGH THE END OF THE PERIOD. A COOL FRONT REACHES THE LOWER LAKES LATE WED. ALL THIS PUTS THE AREA IN THE WARM SECTOR AND ALLOWS THE SERN COS TO MAKE ANOTHER RUN AT 90F. THE CLOUDS WILL BE THE TEMPERING FACTOR ON WEDNESDAY...KNOCKING A FEW DEGS OFF THE POTENTIAL MAXES. THEY WILL ALSO PLAY A ROLE IN THE POTENTIAL FOR SEVERE WEATHER ON WEDNESDAY AFTN/EVENING. CAPES O/O OF 2000 ARE POSSIBLE...BUT MAY NOT BE REALIZED. ALSO...WIND FIELD IS NOT ALL THAT STRONG AS SPC POINTS OUT. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... COOL FRONT SHOULD PUSH INTO THE AEA EARLY WED NIGHT AND MIGHT CLEAR THE SERN COS BY THURSDAY SUNRISE. HOWEVER...POPS IN THE CHC RANGE STILL A STRONG FORECAST FOR THE SERN HALF OF THE AREA LATE WED NIGHT AND ALL THURS DUE TO UNCERTAINTY OF HOW FAR S THE DRIER AIR WILL BE ABLE TO NUDGE THE CONVECTION. MEDIUM RANGE MODEL AND ENSEMBLE GUIDANCE CONTINUES TO ADVERTISE ANOTHER ANOMALOUS MERIDIONAL LARGE SCALE PATTERN EARLY IN THE PERIOD...AS TROUGHING/UPPER LOW DROPS SOUTHWARD ALONG/WEST OF THE APPALACHIANS...AND FOUR CORNERS RIDGE MAINTAINS ITS POSITION. THE AMPLIFIED FLOW OVER THE CONUS SHOULD EVOLVE AND REVERT BACK TO A MORE TYPICAL SUMMERTIME CONFIGURATION DURING THE SECOND HALF OF THE PERIOD...AS THE JET STREAM RETREATS NORTHWARD TO THE U.S./CANADIAN BORDER AND LARGE SUBTROPICAL RIDGE TAKES UP RESIDENCE OVER MUCH OF THE LOWER 48. IN TERMS OF SENSIBLE WX IMPACTS...A SURGE OF MUCH DRIER/BELOW NORMAL PWAT AIR SHOULD FOLLOW BEHIND THE COLD FROPA ON THURSDAY. THIS SHOULD PROVIDE A BRIEF BREAK IN THE HUMID/MUGGY CONDITIONS LATER THIS WEEK. THE FRONTAL BOUNDARY APPEARS TO STALL-OUT OVER THE SRN MID-ATLC STATES BEFORE DRIFTING BACK TO THE WEST TOWARD THE APPALACHIANS...INTERCEPTING A MODEST /NEAR-NORMAL PWATS/ MOISTURE FLOW AROUND THE BERMUDA HIGH. AS SUCH...LOOK FOR TEMPERATURES AND TREND UPWARD INTO NEXT WEEK ACCOMPANIED BY RETURNING SUMMERTIME HUMIDITY. && .AVIATION /08Z TUESDAY THROUGH SATURDAY/... LATE EVENING RADAR LOOP SHOWS A DWINDLING AREA OF SHRA ACROSS THE SUSQ VALLEY IN VICINITY OF A DEPARTING UPPER LVL LOW PRES SYSTEM. JUST A SLIGHT CHC OF A BRIEF VSBY REDUCTION FROM THESE SHRA THRU 04Z AT IPT...MDT AND LNS. BRIEF CLEARING AHEAD OF NEXT LOW PRES SYSTEM COULD RESULT IN SOME FOG AFTER MIDNIGHT...MAINLY IN THOSE LOCATIONS THAT RECEIVED RAIN EARLIER THIS EVENING...SUCH AS UNV. NEXT LOW PRES SYSTEM APPROACHING FROM THE GRT LKS WILL LIKELY BRING ANOTHER ROUND OF SHRA TO THE AREA EARLY TUE AM. THICKENING CLOUD COVER AHEAD OF THIS FEATURE SHOULD PUT A BREAK ON THE RADIATIONAL COOLING AND FOG FORMATION AFTER ABOUT 06Z-08Z. HOWEVER...MVFR VSBYS STILL POSSIBLE LATE TONIGHT IN ANY HEAVIER SHOWERS. MODEL GUIDANCE SUGGESTS LOW PRES TROUGH AND ASSOC SHOWERS WILL IMPACT THE ENTIRE AREA LATE TUE AM WITH LIMITED RESTRICTIONS. A MOIST SW FLOW ASCENDING THE NW MTNS COULD PRODUCE SOME PERSISTENT MVFR CIGS AT BFD BTWN 12Z-18Z TUESDAY. ELSEWHERE...PREDOMINANTLY VFR CONDS ARE LIKELY BY NOON. HOWEVER...ISOLD LATE DAY THUNDERSTORM IMPACTS ARE POSSIBLE IN ASSOCIATION WITH LINGERING TROUGH OF LOW PRES OVR THE AREA. OUTLOOK... WED...AM LOW CIGS POSS NW MTNS. SCT TSRA IMPACTS POSSIBLE. THU...AM LOW CIGS POSS W MTNS. SCT TSRA IMPACTS POSSIBLE. FRI-SAT...NO SIG WX EXPECTED. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...DANGELO NEAR TERM...DANGELO SHORT TERM...DANGELO LONG TERM...STEINBUGL AVIATION...FITZGERALD
AREA FORECAST DISCUSSION
NWS MIDLAND/ODESSA TX
1222 AM CDT TUE JUL 9 2013 .DISCUSSION... SEE 06 AVIATION DISCUSSION BELOW. && .AVIATION... GUSTY SOUTH TO SOUTHEAST WINDS WILL DIMINISH IN STRENGTH OVER THE NEXT FEW HOURS. WINDS WILL ONCE AGAIN BECOME GUSTY AT MOST LOCATIONS MID MORNING TUESDAY. THERE IS A SLIGHT POSSIBILITY OF MVFR CEILINGS AT MAF AND FST FOR EARLY TUESDAY MORNING BUT CONFIDENCE REMAINS LOW. && PREV DISCUSSION... /ISSUED 229 PM CDT MON JUL 8 2013/ DISCUSSION... AN UPPER LEVEL DISTURBANCE PASSING BY TO THE SOUTH ACROSS THE BIG BEND COULD GENERATE ISOLATED THUNDERSTORMS THIS EVENING ACROSS WEST TEXAS PER CUMULUS FIELD AND LATEST RUC GUIDANCE. ANY ACTIVITY SHOULD DIE THIS EVENING WITH LOSS OF HEATING. THIS DISTURBANCE IS FORECAST TO CONTINUE TO SLOWLY TRACK WESTWARD ACROSS NORTHERN MEXICO TUESDAY AND TUESDAY EVENING WITH ISOLATED TO WIDELY SCATTERED SHOWERS AND THUNDERSTORMS POSSIBLE AGAIN ACROSS THE BIG BEND...DAVIS MOUNTAINS AND LOWER TRANS PECOS REGION CLOSEST TO THE TRACK OF DISTURBANCE. BEYOND TUESDAY A SPRAWLING UPPER LEVEL HIGH PRESSURE AREA ACROSS THE PLAINS AND ROCKIES SHOULD REGAIN FIRM CONTROL OF THE REGION AND PRECIPITATION CHANCES WILL BE VERY LOW. THE NEXT CHANCE OF CONVECTION APPEARS TO BE NEXT SUNDAY AND MONDAY AS ANOTHER DISTURBANCE TRACKS WESTWARD ACROSS THE GULF AND MEXICO. HIGH TEMPERATURES ARE EXPECTED TO BE NEAR NORMAL THROUGH WEDNESDAY WITH ABOVE NORMAL TEMPERATURES EXPECTED THURSDAY THROUGH SATURDAY. && .MAF WATCHES/WARNINGS/ADVISORIES... NM...NONE. TX...NONE. && $$ 99
AREA FORECAST DISCUSSION
NWS SPOKANE WA
1121 PM PDT Mon Jul 8 2013 .SYNOPSIS... A weather system passing through the Inland Northwest today will promote scattered showers and thunderstorms across the northern mountains of Washington and Idaho, as well as southeast Washington. Tuesday and Wednesday will be the warmest days this week with high temperatures in the upper 80s to mid 90s. Thursday through Saturday will be occasionally breezy with temperatures pretty close to average, or slightly below. Low shower and thunderstorms chances will linger near the mountains, especially closer to the Canadian border, but otherwise conditions will be dry. Temperatures begin to warm up again slightly going into early next week. && .DISCUSSION... This Afternoon and Evening: The weather over northeast Washington and the Idaho Panhandle will be active. Scattered thunderstorms are expected through early this evening. Our concern area extends from the Okanogan Highlands through northeast Washington into the northern and central Idaho Panhandle. The 2 PM visible imagery shows a mid-level atmospheric circulation in far southeast British Columbia slowly moving east. Around this circulation the atmosphere has become increasingly unstable with the RUC analysis indicating 500 to 1000 J/KG of surface based CAPE from Republic to Sandpoint to Spokane to Kellogg. Very little convective inhibition remains, so look for convection to continue to develop through late afternoon. Shear and buoyancy values suggest the potential for organized multi-cell thunderstorms. Our main threat through 6 PM will be the potential for hail, heavy rain, and gusty winds. A couple severe thunderstorm warnings may be needed, but most of the cells through early evening will probably pulse up, produce hail up to dime size, then pulse down. The threat for thunderstorms should dissipate quickly early this evening as the upper level support (upper low in SE BC) moves east of the region focusing the threat over Montana. Tuesday: A shortwave ridge of high pressure will replace the trough over the Inland Northwest for Tuesday. Look for relatively light winds, clear skies and temperatures 5 to 8 degrees above average. /GKoch Tuesday night through Thursday evening...General long-wave trof lingers overhead but the air-mass contained in it is not very unstable and does not have much moisture tied to any discrete feature traversing through it. As thus for the most part a dry forecast remains, with exception being minimal chance for afternoon/evening mountain thunderstorms up North and over the Idaho Panhandle Thursday afternoon and evening. Forecast temperatures remain just slightly on the warm side of what would be considered normal for this time of year. Other shortwave features of note will be a dry disturbance passage on Wednesday afternoon and evening which will increase the wind some but only to low breezy category at most. /Pelatti Thursday night through Monday: The Inland Northwest remains in a more active pattern through the week`s end, before high pressure starts to nudge in Sunday and Monday. A shortwave system continues to slip through Idaho into Montana Thursday night, even as a second shortwave begins to move toward the Cascades. That second shortwave slips across eastern Washington and north Idaho through Friday, with a third wave slipping by Saturday before high pressure begins to nudge in Saturday night. Models continue to disagree over some of the details. Yet the progression of these features will bring some shower and thunderstorm chances to the region. The main chances remain around the northern mountains. Smaller chances will be found across the Blue Mountains through the Central Panhandle, including the Palouse as the wave is exiting Thursday night. While some of these waves are depicted as being somewhat dynamic/strong, models still do not depict significant instability and keep the deeper moisture southeast of the region. So regardless of timing and track, fuel for showers is not impressive. Thus over PoPs remain slight or isolated in nature. Look for occasional breezy conditions, especially Friday, with the passage of these waves. Although a couple models skim another wave by southern BC, near the WA/ID border early next week, drier conditions are forecast going into Sunday and Monday. Look for slightly cooler than normal conditions around the end of the work week, before temperatures warm closer to or slightly above seasonal norms going into early next week. /J. Cote` && .AVIATION... 06Z TAFS: Periods of thin high clouds moving through overnight otherwise VFR and light winds for the next 24 hrs. && .PRELIMINARY POINT TEMPS/POPS... Spokane 58 89 60 89 59 83 / 0 0 0 0 0 10 Coeur d`Alene 56 87 58 87 58 83 / 10 0 0 0 0 10 Pullman 53 87 55 88 55 82 / 0 0 0 10 10 10 Lewiston 62 95 64 95 63 90 / 0 0 0 10 10 10 Colville 53 90 56 92 56 86 / 10 0 0 0 0 10 Sandpoint 50 85 53 86 54 82 / 20 0 0 0 0 10 Kellogg 54 87 57 87 58 82 / 10 0 0 0 10 10 Moses Lake 60 94 62 94 60 87 / 0 0 0 0 0 0 Wenatchee 64 92 65 91 62 85 / 0 0 0 0 0 0 Omak 60 94 60 92 59 86 / 0 0 0 0 0 10 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...None. WA...None. && $$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
315 AM CDT TUE JUL 9 2013 .SHORT TERM...(TODAY THROUGH TONIGHT) ISSUED AT 315 AM CDT TUE JUL 9 2013 MAIN CONCERN WILL BE TRACK OF PLAINS THUNDERSTORM COMPLEX THIS MORNING/TODAY...THEN SEVERE POTENTIAL GOING THIS AFTERNOON. LOOP OF WATER VAPOR IMAGERY THIS MORNING ALONG WITH RAP 500MB ANALYSIS SHOWS A FAIRLY VIGOROUS MID-LEVEL TROUGH MOVING OUT OF MT INTO THE DAKOTAS...WHILE ANOTHER WEAKER WAVE WAS NOTED ACROSS CENTRAL NEB. 925-850MB MOISTURE TRANSPORT AHEAD OF THESE WAVES WAS PRODUCING A BROKEN LINE COMPLEX OF THUNDERSTORMS EXTENDING FROM EASTERN ND/SD...INTO EASTERN NEB. THIS COMPLEX OF STORMS WAS MOVING EAST AT 30-35KT...MAKING INROADS TOWARD THE AREA. SIMPLE EXTRAPOLATION BRINGS THIS COMPLEX INTO SOUTHEAST MN/NORTHEAST IA AROUND 12Z/7AM-ISH. ARX/HRRR/NMM WRF MODELS DID A PRETTY GOOD JOB INITIALIZING THIS CONVECTION AND REMAIN IN FAIRLY DECENT AGREEMENT THROUGH THE DAY TODAY. HAVE TRENDED THE FORECAST TO MATCH UP WITH A BLEND OF THESE SOLUTIONS. APPEARS THE COMPLEX OF STORMS WILL MAINTAIN ITSELF...COMING ACROSS THE AREA THIS MORNING AS 925-850MB MOISTURE TRANSPORT INCREASES/NOSES INTO THE REGION. THIS COMPLEX OF STORMS HAS A HISTORY OF 30-50KT WINDS ASSOCIATED WITH IT OVER SD. SO...CANNOT RULE OUT SOME BORDERLINE SEVERE WINDS AS IT ROLLS INTO OUR AREA. COULD BE INTERESTING GOING INTO THIS AFTERNOON AS THE WRF MODELS SHOW THIS COMPLEX DEVELOPING A FAIRLY SIGNIFICANT MCV STRUCTURE. THIS IN TURN HAS THE POTENTIAL OF PRODUCING A MINI-OUTFLOW/COLD FRONT ON ITS SOUTHWEST FLANK IN THE 18-21Z TIME FRAME. WITH AMPING SHEAR IN THE 30-40KT RANGE DUE TO THE MCV AND MORE THAN AMPLE CAPE IN THE 4000-5500J/KG RANGE...LOOKING FOR THE POSSIBILITY OF A LINE OF SEVERE STORMS WITH DAMAGING WINDS DEVELOPING ACROSS CENTRAL/SOUTHWEST WI THIS AFTERNOON. THIS OF COURSE WILL ALL DEPEND ON HOW MUCH CLOUD IS PRESENT WHICH COULD AFFECT THE AMOUNT OF AVAILABLE INSTABILITY REALIZED. THE POTENTIAL IS DEFINITELY THERE AND WILL HAVE TO BE WATCHED CLOSELY. ANOTHER THING TO WATCH IS HEAVY RAINFALL POTENTIAL WITH MUGGY AIRMASS IN PLACE AND PRECIPITABLE WATER IN THE 2-2.25 INCH RANGE. THIS COULD AID IN TORRENTIAL DOWNPOURS OUT OF THE STORMS AND SOME LOCALIZED PONDING OF WATER IN POOR DRAINAGE AREAS. LOOKING FOR THE MAIN COLD FRONT TO THEN SLIDE SOUTHEAST ACROSS THE AREA IN THE 00-06Z TIME FRAME. UNCERTAIN ON HOW THIS IS GOING TO PLAY OUT WITH THE POTENTIAL FOR SEVERE STORMS ALREADY GOING THROUGH THE AREA THIS AFTERNOON. ATMOSPHERE COULD BE FAIRLY STABILIZED BEHIND THIS CONVECTION AND COLD FRONT COULD SLIP THROUGH WITH NO CONVECTION. APPEARS HIGHEST POTENTIAL FOR EVENING CONVECTION MAY BE ALONG AND NORTH OF I-94 WHERE BETTER 500-300MB PV-ADVECTION WILL EXIST. EXPECTING COLD FRONT AND ASSOCIATED CONVECTION TO PUSH EAST OF THE AREA AROUND DAYBREAK AS HIGH PRESSURE BUILDS IN FROM THE DAKOTAS. && .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 315 AM CDT TUE JUL 9 2013 HIGH PRESSURE WILL PRODUCE VERY PLEASANT WEATHER CONDITIONS ACROSS THE AREA WEDNESDAY AND THURSDAY. LOOK FOR HIGHS IN THE 75-80 DEGREE RANGE ON WEDNESDAY AND UPPER 70S/LOWER 80S ON THURSDAY. MUCH LOWER HUMIDITY LEVELS WILL ALSO BE NOTED AS DEWPOINTS HOVER IN THE 50S. PLAN ON WARMER TEMPERATURES ON FRIDAY ALONG WITH INCREASING HUMIDITY LEVEL AS THE HIGH SLIDES OFF TO THE EAST AND SOUTH WINDS SET UP ACROSS THE AREA. LOOK FOR HIGHS IN THE 80S WITH A FEW READINGS FLIRTING WITH THE 90 DEGREE MARK ACROSS SOUTHEAST MN. EC/GFS ACTUALLY IN PRETTY GOOD AGREEMENT GOING INTO THE WEEKEND. BOTH MOVE A COLD FRONT INTO THE UPPER MISSISSIPPI RIVER REGION BY SUNDAY MORNING...THEN HANG IT UP ACROSS WI INTO CENTRAL IA BY MONDAY. THIS WILL PRODUCE A CHANCE OF SHOWERS AND THUNDERSTORMS FROM FRIDAY NIGHT STRAIGHT THROUGH MONDAY. OTHERWISE...LOOK FOR TEMPERATURES TO BE RIGHT AROUND NORMAL LEVELS IN THE 80S. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1153 PM CDT MON JUL 8 2013 THE AVIATION FORECAST IS VERY UNCERTAIN FOR THE NEXT 24 HOURS... PARTICULARLY WITH THUNDERSTORMS. SKIES ARE MAINLY CLEAR AT THE TAF SITES AS OF 056Z. WITH DEWPOINTS STILL SITTING UP AROUND 70F AND TEMPERATURES COOLING...ANTICIPATING MVFR BR TO FORM AROUND 09Z. TO THE WEST...CLUSTERS OF SHOWERS AND THUNDERSTORMS ARE PRESENT ACROSS THE DAKOTAS INTO NEBRASKA. THESE ARE DEVELOPING AND MOVING SLOWER THAN PREVIOUS COMPUTER MODELS HAVE FORECAST...THUS HAVE DELAYED THE TIMING OF THEM IMPACTING THE TAF SITES EVEN MORE. PRESENTLY HAVE THE SHOWERS AND STORMS IMPACTING RST BETWEEN 13-17Z AND LSE BETWEEN 14-18Z. STILL NOT ENOUGH CONFIDENCE EXISTS TO CHANGE THE VCTS TO -TSRA GIVEN THE POTENTIAL FOR THE THUNDERSTORMS TO BE SCATTERED IN COVERAGE. CONTINUED TO SUGGEST A GENERAL BREAK IN THE PRECIPITATION UNTIL A COLD FRONT APPROACHES DURING THE EVENING. HOWEVER...WITH SOME COMPUTER MODELS SHOWING POTENTIAL FOR SHOWERS AND STORMS TO LINGER THROUGH THE AFTERNOON...MAINTAINED A VCSH. WITH THE COLD FRONT HAVE ADDED A PERIOD OF VCTS FOR ABOUT 4 HOURS. IT IS POSSIBLE THIS IS TOO LONG...BUT THERE ARE UNCERTAINTIES ON THE TIMING AND IT DOES APPEAR THE FRONT SHOULD HAVE SOME THUNDERSTORMS ON IT. REGARDING THUNDERSTORM IMPACTS. THOSE DURING THE MORNING WILL LIKELY KNOCK VISIBILITIES AND CEILINGS TO MVFR AND HAVE TO POTENTIAL TO PRODUCE HEAVY RAIN. THOSE FOR THE EVENING COULD PRODUCE STRONG TO SEVERE WIND GUSTS...ALONG WITH HEAVY RAIN AND BRIEF VISIBILITY RESTRICTION. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...DAS LONG TERM....DAS AVIATION...AJ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1153 PM CDT MON JUL 8 2013 .UPDATE... ISSUED AT 942 PM CDT MON JUL 8 2013 TRYING TO FIGURE OUT THE CONVECTIVE EVOLUTION FORECAST FROM THE OVERNIGHT HOURS THROUGH TUESDAY REMAINS VERY PROBLEMATIC. FIRST...A LINE OF SHOWERS AND THUNDERSTORMS SET UP JUST NORTH OF US-20 AND NEAR THE CLAYTON/GRANT COUNTY LINE. THESE STORMS WERE ALONG A QUASI-STATIONARY FRONTAL BOUNDARY AND AIDED BY MLCAPES OF 2000-2500 J/KG PER RAP ANALYSIS. THEY HAVE BEEN VERY EFFICIENT RAIN PRODUCERS WITH RAINFALL RATES OF 1 TO 2 INCHES PER HOUR BEING OBSERVED IN EDGEWOOD AND GREELEY IA. LACK OF ANY 0-6KM SHEAR HAS RESULTED IN THE STORMS COLLAPSING. ADDITIONALLY...LOSS OF DAYTIME HEATING ALLOWING THE CAPE TO DIMINISH...THOUGH DEWPOINTS UP IN THE MID 70S POOLED ALONG THE BOUNDARY RESULTING IN A SLOW DIMINISHMENT. ANTICIPATING THESE STORMS MAY END UP FALLING PART IN THE NEXT HOUR. NOW FOR THE OVERNIGHT INTO TUESDAY. CONVECTION ACROSS SOUTH DAKOTA AND NEBRASKA HAS BEEN MUCH LESS THAN WHAT MANY MODELS UP TO THIS POINT HAD SUGGESTED...INCLUDING HIGH RESOLUTION MODELS. THUS...THE IDEA OF AN MCS ROLLING OUT OF THIS REGION AND IMPACTING THE FORECAST AREA LATE TONIGHT IS VERY MUCH IN QUESTION. LOOKING AT OBSERVATIONAL DATA...THERE IS A SHORTWAVE OVER SOUTHWEST SOUTH DAKOTA INTO FAR WESTERN NEBRASKA WITH ISOLATED CONVECTION ACCOMPANYING IT. AHEAD OF THE SHORTWAVE...850MB WINDS HAVE BEEN INCREASING OVER KANSAS AND NEBRASKA PER RADAR/PROFILER DATA...WITH HINTS OF A WARM FRONTAL ZONE ACROSS SOUTHERN NEBRASKA. THIS IS SHOWN TOO IN LATEST SURFACE ANALYSIS. ONCE THESE FEATURES MEET UP...LIKELY IN CENTRAL/EASTERN NEBRASKA...WOULD IMAGINE CONVECTION WILL INCREASE THERE. THE CONVECTION WILL LIKELY HEAD EAST THROUGH THE MEAN FLOW TOWARDS SOUTHERN SECTIONS OF THE FORECAST AREA...UNLESS IT UPSCALES INTO AN MCS...WHICH THEN MAY HEAD SOUTHEAST AWAY FROM THE AREA PER BOTH NORMAL CORFIDI VECTORS AND PROPAGATING CORFIDI VECTORS. HEADING INTO TUESDAY...THERE ARE INDICATIONS FROM THE 09.00Z NAM/RAP...08.12Z ECMWF/REGIONAL CANADIAN AND 08.18Z GFS OF 850MB MOISTURE TRANSPORT PICKING UP ACROSS CENTRAL IOWA...WITH THE NOSE OF IT POINTED RIGHT INTO THE FORECAST AREA AT 18Z. THIS COULD CONCEIVABLY INITIATE PLENTY OF CONVECTION FROM LATE MORNING THROUGH A BULK OF THE AFTERNOON HOURS. THESE WOULD BE EFFICIENT RAIN PRODUCERS GIVEN DEEP WARM CLOUD DEPTHS AND PRECIPITABLE WATER VALUES UPWARDS OF 2 INCHES. IF THIS CONVECTION FORMS...BY THE TIME THE COLD FRONT COMING THROUGH MINNESOTA APPROACHES THE FORECAST AREA IN THE EVENING...WE MAY NOT HAVE ENOUGH INSTABILITY TO DO MUCH WITH IT. WE WILL JUST HAVE TO SEE HOW OVERNIGHT CONVECTION PLAYS OUT...SINCE AN MCV GOING SOUTH OF US COULD PRODUCE ENOUGH SUBSIDENCE TO PRECLUDE MUCH CONVECTION IN ITS WAKE FOR TUESDAY. THE PRESENCE OF THE MCV WOULD LIKE DISTORT THE PROGGED 850MB MOISTURE TRANSPORT ZONE TOO. TUESDAY THEN WOULD BE A VERY WARM DAY AGAIN WITH HIGHS ABOVE CURRENT FORECAST...WITH SEVERE WEATHER POTENTIAL IN THE EVENING AS THE COLD FRONT MOVES IN. && .SHORT TERM...(TONIGHT THROUGH TUESDAY) ISSUED AT 250 PM CDT MON JUL 8 2013 WARM FRONT SLATED TO WAVER WEST-EAST ACROSS SOUTHERN IA TONIGHT/TUE. THE LOW LEVEL JET/MOISTURE TRANSPORT FOCUSES INTO THE BOUNDARY ACROSS CENTRAL IA TONIGHT...AND SHOWER/STORMS SHOULD DEVELOP AS A RESULT. THE LOW LEVEL FORCING PUSHES NORTHEAST ACROSS THE FORECAST AREA TUE MORNING WHILE A PIECE OF UPPER LEVEL ENERGY TRACKS FROM THE NORTHERN PLAINS TO ACROSS THE UPPER MISSISSIPPI RIVER VALLEY BETWEEN 12-18Z. WOULD EXPECT TO SEE A SHIFT NORTHWARD WITH THE MORE FAVORABLE CONVECTIVE REGION AS A RESULT...MOSTLY ALONG AND NORTH OF I-90. A STRONGER UPPER LEVEL SHORTWAVE TROUGH PROGGED TO SLIP ACROSS THE NORTHERN PLAINS AND INTO NORTHERN MN BY 00Z WED. A COLD FRONT WILL SURGE AHEAD OF THIS SHORTWAVE...GETTING TO THE MISSISSIPPI RIVER BY 00Z. THE GFS AND NAM BUILD 4000+ J/KG OF MUCAPE AHEAD OF THE FRONT...WITH 40+ KTS OF 0-6 KM SHEAR. INSTABILITY WILL DEPEND ON HOW LONG THE MORNING SHOWERS/STORMS LINGER ACROSS THE LOCAL AREA...AND HOW QUICKLY THE DEBRIS CLOUDS CLEAR. AS IT STANDS...IF PARAMETERS MANIFEST PER MODELED FORECAST...IT WOULD BE A GOOD SETUP FOR SEVERE WEATHER. HOWEVER...IF PCPN LINGERS LINGERS...INSTABILITY WILL BE MUCH LOWER...LESSENING THE SEVERE THREAT. A VERY CONDITIONAL SEVERE WEATHER THREAT THAT WON/T BECOME CLEARER UNTIL THE AFTERNOON HOURS. HERE IS HOW TUE COULD PLAY OUT...MORNING CONVECTION ASSOCIATED WITH THE LOW LEVEL JET ADVANCES NORTHEAST ACROSS THE REGION. COULD BE SOME LINGERING SHOWERS/STORMS IN THE AFTERNOON...BUT ENVISION A BREAK FROM THE WIDESPREAD PCPN CHANCES. SHOWERS/STORMS SPARK ALONG AND AHEAD OF THE COLD FRONT BY LATE AFTERNOON/EVENING. MAYBE A BETTER CHANCE NORTH OF I-94. ALSO...BELIEVE THE HIGHER SEVERE RISK WILL BE DURING THIS TIME. .LONG TERM...(WEDNESDAY THROUGH SUNDAY) ISSUED AT 250 PM CDT MON JUL 8 2013 HIGH PRESSURE BUILDS ACROSS THE UPPER MISSISSIPPI RIVER VALLEY FROM THE WEST ON WEDNESDAY...AND LOOKS TO BE THE MAIN WEATHER INFLUENCE THROUGH THE BETTER PART OF FRIDAY. THE HEAT/HUMIDITY OF THE PAST FEW DAYS WILL SWEEP EAST DURING THIS PERIOD...WITH COMPARATIVELY COOLER AND LESS MUGGY CONDITIONS RESULTING. AN UPPER LEVEL SHORTWAVE TROUGH IS THEN SLATED TO DRIVE FROM THE PAC NW TO ACROSS SOUTHERN CANADA FOR THE UPCOMING WEEKEND. WHILE CURRENT TRENDS FAVOR KEEPING MOST OF THE UPPER LEVEL ENERGY NORTH OF THE FORECAST AREA...THE GFS AND ECMWF WOULD SLIDE AN ASSOCIATED COLD FRONT ACROSS THE REGION. WITH THE WINDS FLIPPING TO THE SOUTH AS THE HIGH EEKS TO THE EAST...LOW LEVEL MOISTURE WOULD INCREASE AHEAD OF THE SFC BOUNDARY...AS WOULD INSTABILITY. EXPECT SOME CONVECTION AROUND THE FRONT AS RESULT. DETAILS ON WHEN/WHERE ISN/T CLEAR AT THIS TIME...WITH SOME MODEL DIFFERENCES ON TIMING AND PLACEMENT OF THE RELEVANT FEATURES. THE SFC FRONT COULD THEN GET HUNG UP FROM WEST TO EAST ACROSS THE REGION...SERVING AS A POSSIBLE SHOWER/STORM FOCUS THROUGH THE WEEKEND. WILL LEAN ON THE CONSENSUS/EC SOLUTION FOR PCPN CHANCES FOR NOW. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1153 PM CDT MON JUL 8 2013 THE AVIATION FORECAST IS VERY UNCERTAIN FOR THE NEXT 24 HOURS... PARTICULARLY WITH THUNDERSTORMS. SKIES ARE MAINLY CLEAR AT THE TAF SITES AS OF 056Z. WITH DEWPOINTS STILL SITTING UP AROUND 70F AND TEMPERATURES COOLING...ANTICIPATING MVFR BR TO FORM AROUND 09Z. TO THE WEST...CLUSTERS OF SHOWERS AND THUNDERSTORMS ARE PRESENT ACROSS THE DAKOTAS INTO NEBRASKA. THESE ARE DEVELOPING AND MOVING SLOWER THAN PREVIOUS COMPUTER MODELS HAVE FORECAST...THUS HAVE DELAYED THE TIMING OF THEM IMPACTING THE TAF SITES EVEN MORE. PRESENTLY HAVE THE SHOWERS AND STORMS IMPACTING RST BETWEEN 13-17Z AND LSE BETWEEN 14-18Z. STILL NOT ENOUGH CONFIDENCE EXISTS TO CHANGE THE VCTS TO -TSRA GIVEN THE POTENTIAL FOR THE THUNDERSTORMS TO BE SCATTERED IN COVERAGE. CONTINUED TO SUGGEST A GENERAL BREAK IN THE PRECIPITATION UNTIL A COLD FRONT APPROACHES DURING THE EVENING. HOWEVER...WITH SOME COMPUTER MODELS SHOWING POTENTIAL FOR SHOWERS AND STORMS TO LINGER THROUGH THE AFTERNOON...MAINTAINED A VCSH. WITH THE COLD FRONT HAVE ADDED A PERIOD OF VCTS FOR ABOUT 4 HOURS. IT IS POSSIBLE THIS IS TOO LONG...BUT THERE ARE UNCERTAINTIES ON THE TIMING AND IT DOES APPEAR THE FRONT SHOULD HAVE SOME THUNDERSTORMS ON IT. REGARDING THUNDERSTORM IMPACTS. THOSE DURING THE MORNING WILL LIKELY KNOCK VISIBILITIES AND CEILINGS TO MVFR AND HAVE TO POTENTIAL TO PRODUCE HEAVY RAIN. THOSE FOR THE EVENING COULD PRODUCE STRONG TO SEVERE WIND GUSTS...ALONG WITH HEAVY RAIN AND BRIEF VISIBILITY RESTRICTION. && .HYDROLOGY...(TUESDAY) ISSUED AT 250 PM CDT MON JUL 8 2013 PWS CLOSE TO 2 INCHES THROUGH TUE...AROUND 170 PERCENT OF NORMAL...WHILE WARM CLOUD DEPTH IS 3500-4000 M. ALL SUPPORT THE POTENTIAL FOR HEAVY RAIN. HOWEVER...THE EXPECTED PCPN LOOKS TRANSITORY...NOT LINGERING NOR MUCH TRAINING....WHILE FFG IS 2.5-3 INCHES IN 3 HOURS. THE MOISTURE TRANSPORT ISN/T OVERLY STRONG NOR DOES IT FOCUS FOR A PROLONGED PERIOD. SO...WHILE THE ATMOSPHERE COULD SUPPORT HEAVY RAIN...OTHER ASPECTS MINIMIZE A FLASH FLOOD THREAT. IF PCPN RATES COULD BECOME HIGH ENOUGH...FLASH FLOODING OR URBAN/CITY FLOODING WOULD BE POSSIBLE. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ UPDATE...AJ SHORT TERM...RIECK LONG TERM....RIECK AVIATION...AJ HYDROLOGY....DAS
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
1132 PM CDT MON JUL 8 2013 .UPDATE... ISOLATED THUNDERSTORMS CONTINUE TO POP-UP ALONG OUTFLOW BOUNDARIES WITHIN REGION OF SURFACE MOISTURE FLUX CONVERGENCE OVER FAR SRN WI AND NRN IL. RAPID UPDATE/HI-RES MODELS CONTINUE TO SHOW A DOWNWARD TREND TO CONVECTION OVER THE REGION THROUGH THE NIGHT WITH THE FOCUS SHIFTING TO MCS DEVELOPMENT CURRENTLY OCCURRING OVER THE DAKOTAS MOVING EAST THROUGH IOWA/MINNESOTA AND REACHING WESTERN WISCONSIN SOMETIME BETWEEN 12Z AND 18Z TUESDAY. TIMING DIFFERENCE IS CRITICAL TO SEVERE POTENTIAL FOR TUESDAY AS MCS TRACK WILL HAVE AN IMPACT ON LOCATION OF EFFECTIVE BOUNDARY. PRECIPITATION TOO LONG INTO THE DAY AND/OR CLOUD DEBRIS COULD REDUCE HEATING AND SUBSEQUENT INSTABILITY. OPERATIONAL MODELS STILL LOOKING AT MAIN CONVECTIVE EVENT TO OCCUR LATE AFTERNOON/EVENING AHEAD OF...AND WITH PASSAGE OF MAIN SHORT WAVE TROUGH AND ASSOCIATED SURFACE COLD FRONT. LIGHT FOG OVER MAINLY THE NORTHEAST THIRD OF FORECAST AREA...WHERE LAKE BREEZE...ENHANCED BY OUTFLOW FROM EARLIER STORMS HAS COOLED TEMPS TOWARD DEW POINTS THAT ARE LOWER THAN EARLIER IN THE DAY AS WELL WITH SLIGHTLY DRIER AIR ADVECTING IN ON NE WINDS. RUC AND NAM VISIBILITY FORECASTS HOLD CHANCES FOR 1/4 MILE TO THE EAST OF THE KETTLE MORAINE..WITH THE LATEST NAM MOS GUIDANCE KEEPING VSBYS NO LOWER THAN 1 TO 2 MILES. WILL KEEP PATCHY FOG FOR NOW AND SEE HOW FOG DEVELOPS...THOUGH SBM IS DOWN TO 1/4 MILE. && .AVIATION/06Z TAFS/... EXPECT CURRENT DEVELOPING MVFR VSBYS TO FALL TO IFR IN FOG OVERNIGHT. NOT EXPECTING LIFR...BUT WILL HAVE TO WATCH KENW FOR 1/2 MILE VSBYS. DO NOT EXPECT MUCH MORE IN THE WAY OF CONVECTION UNTIL APPROACH OF SHORT WAVE TROUGH AND SURFACE COLD FRONT TRAILING FROM ATTENDANT SURFACE LOW CROSSING SRN CANADA TUESDAY. MODELS SUGGEST AN MCS...OR ITS REMAINS...MOVING ACROSS SRN WI TUESDAY MORNING INTO EARLY AFTERNOON...THEN THE SECOND ROUND WITH A BETTER CHANCE OF SEVERE IN THE AFTERNOON AND EVENING WITH THE FRONT. && .MARINE... ADDED AREAS OF FOG IN THE NSH BASED ON SHORE BASED WEB CAMS JUST BEFORE DARK AND WITH FOG PRODUCT SHOWING AN EXPANDING AREA OF LOW STRATUS OVER MAINLY THE NORTHERN HALF OF THE LAKE. MODEL LOW-LAYER WINDS SEEM TO FAVOR HOLDING THE LOW STRATUS OFF TO THE EAST...BUT WILL HAVE TO BE WATCHED FOR POSSIBLE MARINE DENSE FOG ADVISORY IF IT MOVES TO THE WESTERN SHORE. POSSIBLE THUNDERSTORMS IN THE LATE MORNING/EARLY AFTERNOON WITH MCS...THEN SECOND ROUND OF STORMS WITH THE BETTER POTENTIAL FOR SEVERE IN THE LATE AFTERNOON/EVENING. && .PREV DISCUSSION... /ISSUED 305 PM CDT MON JUL 8 2013/ SHORT TERM... TONIGHT - CONFIDENCE...MEDIUM WARM/UNSTABLE AIRMASS HAS GENERATED A FEW SHRA ACROSS NE CWA THIS AFTERNOON VICINITY OF INSTABILITY GRADIENT AND SURFACE FRONTOGENESIS PER SPC MESO PAGE. OVERALL 500 MILLIBAR RIDGING SHOULD KEEP MOST AREAS DRY FOR MUCH OF THE NIGHT. FOCUS SHIFTS BACK TO THE WEST WITH THE NEXT SHORT WAVE APPROACHING. IN RESPONSE TO THE LOW LEVEL CYCLOGENESIS...A STRENGTHENING LOW LEVEL JET WILL BRING ANOTHER SURGE OF MOISTURE INTO THE UPPER MIDWEST. EXPECTING AN MCS TO DEVELOP WEST OF WISCONSIN OVERNIGHT...AND PERHAPS AFFFECT THE SW CWA LATE IN THE NIGHT. WARM AND HUMID CONDITIONS WILL PERSIST THROUGH THE OVERNIGHT HOURS. MAV/MET AND SREF PROBS POINTING TO POTENTIAL FOR FOG. IN FACT SOME RATHER LOW VSBYS FORECAST BY MOS. WITH THE ABUNDANT LOW LEVEL MOISTURE...SOUTHWARD SAGGING FRONTAL BOUNDARY...AND LIGHT WIND REGIME...WILL HAVE SOME FOG IN THE GRIDS FOR LATER TONIGHT. TUESDAY - CONFIDENCE...MEDIUM COMPLEX DAY SETTING UP. THE MORNING WILL BE COMPRISED OF DEALING WITH FOG TRENDS ALONG AND NORTH OF WHERE SURFACE BOUNDARY IS SITUATED. IN ADDITION CONVECTION LIKELY ONGOING IN PARTS OF THE AREA. AS THE MCS ARRIVES ANY FOG SHOULD GRADUALLY THIN OUT. THEN THE WAITING GAME WILL START FOR RENEWED CONVECTIVE DEVELOPMENT AS THE DAY WEARS ALONG. A MORE VIGOROUS SHORTWAVE WILL BE APPROACHING FROM MN LATER IN THE DAY. DETAILS OF WHERE THE LOW LEVEL BOUNDARY SETS UP WILL HAVE TO BE SORTED OUT AFTER MORNING CONVECTION...THOUGH MAJORITY OF AVAILABLE GUIDANCE/CIPS ANALOGS AND SPC SWODY2 SUPPORT STRONG/SEVERE STORMS REFIRING WITH A NOD TOWARDS DAMAGING WINDS AND HEAVY RAINS. PROGGD ML CAPE VALUES/LI/S/PWS ARE ALL SUPPORTIVE OF MODERATE TO STRONG INSTABILITY AND AN AIRMASS LOADED WITH MOISTURE. SO STORMS WILL BE VERY EFFICENT RAIN PRODUCERS. TUESDAY NIGHT AND WEDNESDAY...FORECAST CONFIDENCE HIGH. THE MAIN MID/UPPER SHORTWAVE MOVES ACROSS LAKE SUPERIOR THURSDAY NIGHT AND EXITS THE LAKE HURON AREA WEDNESDAY. SOUTHERN WISCONSIN IS IN THE RIGHT ENTRANCE REGION OF AN 85 KNOT 250 MB JET TUESDAY EVENING. THE UPPER FLOW IS DIFLUENT WITH WEAK TO MODERATE UPPER DIVERGENCE. THE CWASP VALUES STILL APPROACH 65 PERCENT ON THE NAM DURING THE AFTERNOON AND EVENING. ZERO TO 3 KM EHI VALUES ARE QUITE HIGH ACROSS NORTHWEST ILLINOIS EARLY IN THE EVENING...WITH VALUES AROUND 5. EHI VALUES ARE NEAR 2 TO 3 ACROSS MUCH OF SOUTH CENTRAL WISCONSIN AND WESTERN PORTIONS OF SOUTHEAST WISCONSIN INDICATING SOME TORNADO POSSIBILITY AS WELL. THE CIPS ANALOGS HAVE MAINLY SEVERE WIND EVENTS...BUT THERE ARE SOME TORNADO EVENTS WITH PROBABILITIES OF 2 TO 5 PCT WITHIN 40 KM OF A GRID POINT OVER MUCH OF THE FORECAST AREA. MUCH WILL DEPEND ON WHETHER A MORNING MESOSCALE CONVECTIVE COMPLEX MOVES ACROSS THE AREA...AND WHERE THE RETURNING WARM FRONTAL BOUNDARY ENDS UP. THE COLD FRONT EXITS THE FAR SOUTHEAST TUESDAY NIGHT. UNTIL THEN WITH CAPE VALUES AROUND 1500 J/KG IN THE EVENING...THE SEVERE AND HEAVY RAIN THREAT SHOULD CONTINUE. THE 850/700 MB THERMAL RIDGE DROPS SOUTH INTO ILLINOIS TUESDAY NIGHT. DRYING OCCURS AT 850/700 MB AND SURFACE DEW POINTS DROP INTO THE LOWER 60S WEDNESDAY AFTERNOON. THERE IS CONSIDERABLE DRYING IN THE MID AND LOW LEVELS...WITH A STABLE LAYER AROUND 6 TO 10 THSD FT IN THE NAM FORECAST SOUNDINGS. WEDNESDAY NIGHT AND THURSDAY...FORECAST CONFIDENCE HIGH. THE SHORTWAVE REACHES SOUTHEAST CANADA AND THE EASTERN GREAT LAKES...BUT SOUTHERN WISCONSIN IS STILL SOMEWHAT IN THE CYCLONIC FLOW ON THE BACK SIDE OF THE TROUGH. ZERO TO 1 KM CAPE VALUES REACH 600 J/KG THURSDAY AFTERNOON WITH STEEP LOW LEVEL LAPSE RATES. HOWEVER MID LEVELS ARE VERY DRY AND WOULD LIKELY LIMIT ANY DEEP MOIST CONVECTION DUE TO ENTRAINMENT. THICKNESS VALUES DROP TO 564 TO 567 DECAMETERS AS A LARGE SURFACE HIGH BUILDS INTO THE UPPER MISSISSIPPI VALLEY AND WISCONSIN. LONG TERM... THURSDAY NIGHT AND FRIDAY...FORECAST CONFIDENCE HIGH. THE UPPER TROUGH DROPS SOUTH ACROSS THE EASTERN U.S. WITH A LARGE MID/UPPER RIDGE BUILDING FROM THE SOUTHERN ROCKIES INTO WISCONSIN. THE SURFACE HIGH IS OVER THE GREAT LAKES AND UPPER OHIO RIVER VALLEY. TEMPERATURES SHOULD BE ON THE REBOUND AND COULD RISE ABOVE THE GFS MOS VALUES. SATURDAY AND SUNDAY...FORECAST CONFIDENCE MEDIUM TO HIGH. THE UPPER TROUGH/LOW RETROGRADES INTO THE GULF COAST AREA WITH THE LARGE RIDGE STILL FROM THE SOUTHERN ROCKIES INTO WISCONSIN. THE SURFACE HIGH REMAINS IS OVER THE GREAT LAKES. WARM AIR ADVECTION OCCURS FRIDAY NIGHT AND SATURDAY. BOTH THE 12Z GFS AND 00Z ECMWF HAS SOME PRECIPITATION OVER NORTHWEST WISCONSIN...BUT ARE GENERALLY DRY AS IT APPROACHES SOUTHERN WISCONSIN SATURDAY...SO JUST A SLIGHT CHANCE OF SHOWERS AT BEST MAINLY NORTHWEST OF MADISON BY SATURDAY AFTERNOON. MONDAY...FORECAST CONFIDENCE MEDIUM. A SHORTWAVE MOVES ACROSS SOUTHERN CANADA WITH THE MID/UPPER RIDGE EXTENDING MORE EAST TO WEST ACROSS THE MID SECTIONS OF THE U.S. A WEAK COLD FRONT SHOULD MOVE ACROSS SOUTHERN WISCONSIN BUT MODEL PRECIPITATION AMOUNTS ARE LIGHT. AVIATION/00Z TAFS/... ELONGATED FRONTAL BOUNDARY EXTENDS FROM NORTHERN LOWER MI THROUGH CENTRAL WI INTO CENTRAL IOWA. PLENTY OF MVFR CU EXPECTED TO MOSTLY DISSIPATE WITH LOSS OF HEATING. ISOLD SHRA WILL AFFECT LOCALES MAINLY NORTH OF TAF SITES THIS EVE B4 DISSIPATING. MET/MAV MOS DATA ALONG WITH SREF CIG/VSBY PROGS BEAR OUT CONCERN FOR LOW CLOUDS/FOG WITH LIGHTER WIND REGIME EVOLVING TONIGHT INTO EARLY WEDNESDAY WITH SOUTHWARD SAGGING FRONTAL BOUNDARY. CONVECTION LIKELY TO REDEVELOP LATER TONIGHT INTO TUESDAY MORNING WITH RENEWED LOW LEVEL JET AND APPROACH OF ANOTHER 500 MILLIBAR SHORTWAVE. THEN A BREAK BEFORE MORE STORMS ARRIVE MID/LATE AFTERNOON TIME FRAME INTO THE EVENING HOURS. SOME OF THE STORMS MAY BECOME SEVERE. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...NONE. LM...NONE. && $$ UPDATE...REM TONIGHT/TUESDAY AND AVIATION/MARINE...COLLAR TUESDAY NIGHT THROUGH MONDAY...HENTZ
AREA FORECAST DISCUSSION...CORRECTED
NWS NEW YORK NY
1100 AM EDT TUE JUL 9 2013 .SYNOPSIS... A WEAK FRONT ACROSS SOUTHERN CONNECTICUT WILL GRADUALLY RETURN NORTH THIS AFTERNOON. A WEAK TROUGH APPROACHES WEDNESDAY AFTERNOON...WITH A SLOWLY MOVING FRONTAL SYSTEM AFFECTING THE REGION THROUGH THE END OF THE WEEK. A COLD FRONT SLOWLY MOVES THROUGH THE REGION WEDNESDAY NIGHT THROUGH THURSDAY NIGHT...AND THEN STALLS OFFSHORE. HIGH PRESSURE THEN TRIES TO BUILD INTO THE REGION FOR THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... BASED ON LATEST RADAR IMAGERY AND OBS...A WEAK...DIFFUSE COLD FRONT APPEARS TO HAVE PUSHED ACROSS SRN CT...WITH LOCAL SEA- AND SOUND- BREEZES MAKING IT DIFFICULT TO PINPOINT THE EXACT LOCATION. LATEST HRRR MODEL TAKES BOUNDARY SLOWLY NORTH THIS AFTERNOON WITH CONVECTION BEING INITIATED ACROSS INTERIOR CT. ADDITIONAL SCT CONVECTION WILL LIKELY FIRE UP WITH AN APPROACHING SHORT WAVE TROF TO THE NORTH AND WEST OF NYC...BEFORE DISSIPATING NEAR THE COAST EARLY THIS EVE. SEABREEZE BOUNDARY IS ALSO ANOTHER POTENTIAL TRIGGER FOR CONVECTION. DUE TO WEAK STEERING WINDS FROM THE WEST AT 10 KT OR LESS...ANY CONVECTION WILL BE CAPABLE OF BRIEF HEAVY DOWNPOURS. WIND SHEAR IS WEAK WHICH DOES NOT SUPPORT ORGANIZED SEVERE CONVECTION. VERY WARM TEMPS CONTINUE WITH DEWPOINTS INCREASING A TAD AS COMPARED TO YESTERDAY. HEAT INDICES ACROSS NYC METRO AND INTERIOR SHOULD TOP OUT IN THE LOWER 90S ONCE AGAIN. A MODERATE RISK FOR RIP CURRENTS EXISTS AT THE ATLANTIC OCEAN BEACHES OF EASTERN LONG ISLAND TODAY. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/... WEAK VORTS WILL CONTINUE TO ROTATE THROUGH THE REGION TONIGHT INTO WEDNESDAY...AS A TROUGH DIGS INTO THE GREAT LAKES. AT THE SURFACE...THE BACK DOOR FRONT WILL GRADUALLY PUSH NORTH TONIGHT INTO WEDNESDAY. ON WEDNESDAY...A PRE-FRONTAL TROUGH WILL APPROACH THE REGION IN THE AFTERNOON AHEAD OF A DEVELOPING LOW PRESSURE SYSTEM NEAR HUDSON BAY. MAIN FOCUS FOR ANY SHRA/TSRA TONIGHT SHOULD BE NORTH OF THE REGION WITH LLJ FORCING AND THE NORTHWARD MOVING FRONTAL BOUNDARY OVERNIGHT. OTHERWISE...WITH DIMINISHING INSTABILITY THIS EVENING...WOULD EXPECTED ANY CONVECTION TO GRADUALLY WEAKEN. AN ISOLATED SHRA/TSRA IS POSSIBLE OVERNIGHT WITH INCREASING LLJ...MARGINAL INSTABILITY...AND WEAK VORT ACTIVITY...BUT MAINLY DRY. INCREASINGLY MOIST SOUTHERLY FLOW WILL BRING A POTENTIAL FOR PATCHY FOG AND STRATUS OVERNIGHT. POTENTIAL INCREASES FOR MORE WIDESPREAD CONVECTION ACROSS WESTERN ZONES...BETWEEN APPROACHING PRE-FRONTAL TROUGH AND SEABREEZE BOUNDARY...WEDNESDAY AFTERNOON WITH STRENGTHENING WIND FIELDS AND APPROACHING SHORTWAVE. SEVERE POTENTIAL WILL BE PREDICATED BY AMOUNT OF SUNSHINE...BUT WITH AN INCREASINGLY MOIST AIRMASS A MODERATELY UNSTABLE AIRMASS IS QUITE POSSIBLE IN THE ABOVE MENTIONED AREA. THE OTHER THREAT WILL BE FOR HEAVY RAIN AND POTENTIAL FLASH FLOODING WITH TRAINING CELLS ALONG S/N ORIENTED BOUNDARIES AS PWATS INCREASE TO AROUND 2" AND WARM CLOUD LAYER INCREASES. VERY WARM AND INCREASINGLY HUMID CONDITIONS ON WED...WITH TEMPS IN THE MID TO UPPER 80S NYC/NJ METRO AND INTERIOR...WITH LOWER TO MID 80S ALONG THE COAST IN SOUTHERLY SYNOPTIC FLOW. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... UNSETTLED WEATHER ON TAP FOR THE MIDDLE TO THE END OF THE WEEK AS LOW PRES TRACKING ACROSS EASTERN CANADA DRAGS A COLD THROUGH THE REGION ON THURSDAY. THE FIRST ROUND OF SHOWERS AND POSSIBLE THUNDERSTORMS WILL TAPER OFF IN THE FIRST HALF OF WEDNESDAY NIGHT....AND THEN ADDITIONAL SHOWERS AND POSSIBLE THUNDERSTORMS WILL DEVELOP ON THURSDAY AS WEAK LOW PRES DEVELOPS ALONG THE FRONT AND SLIDES THROUGH THE REGION. WITH PWATS AROUND 2"...CAN EXPECT HEAVY RAIN. SCATTERED TO NUMEROUS SHOWERS/TSTMS WILL IMPACT THE REGION THROUGHOUT THE DAY...TAPERING OFF LATE. BASED ON THE MODEST SW FLOW AND BUILDING SEAS...DANGEROUS RIPS APPEAR LIKELY WED AND THU AT THE OCEAN. COLD FRONT WILL BE THROUGH THE REGION THURSDAY NIGHT AND BECOMES NEARLY STATIONARY EAST OF THE AREA. H5 TROUGH/SHORTWAVE MOVES RIGHT OVER THE AREA ON FRIDAY AND THEN STALLS OUT OVER THE AREA. EVEN THOUGH HIGH PRES BUILDS IN AT THE SFC...WILL HAVE TO KEEP AT LEAST CHANCE POPS IN THE FORECAST FOR THE WEEKEND DUE TO THIS UPPER LEVEL SYSTEM OVER THE AREA. RETURN FLOW SETS UP BRINGING AN INCREASE IN THE HEAT AND HUMIDITY AGAIN ON MON. && .AVIATION /15Z TUESDAY THROUGH SATURDAY/... A TROUGH OF LOW PRESSURE WILL REMAIN OVER THE LOCAL AREA THROUGH TODAY. CONDITIONS WILL REMAIN PRIMARILY VFR TODAY. ONE EXCEPTION IS AT KGON WHERE A WEAK COLD FRONT HAS PUSHED SOUTH AND BROUGHT IFR CIGS. THESE CIGS HAVE BEGUN TO LIFT BUT MVFR/IFR AT TIMES IS STILL ANTICIPATED THROUGH THE AFTERNOON. WINDS WILL BE LIGHT AND MAY VARY TO E/ENE DIRECTION AT KGON/KLGA THROUGH EARLY AFTERNOON. OTHERWISE...LIGHT SW WINDS INCREASE TO 10 AND 15 KT AFTER 18Z. EARLY AFTERNOON SEA BREEZES ARE EXPECTED. SHOWERS AND TSTORMS ARE POSSIBLE TODAY...BUT CONFIDENCE TOO LOW IN TIMING AND PLACEMENT TO INCLUDE IN TAFS. NY METRO ENHANCED AVIATION WEATHER SUPPORT... DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE) KEWR FCSTER COMMENTS: BEST CHANCE FOR SHOWERS/TSTORMS WILL BE AFTER 18Z. THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH IMPLIES SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD. KJFK FCSTER COMMENTS: TIMING OF SEA BREEZE COULD BE OFF BY +/- AN HOUR. BEST CHANCE FOR SHOWERS/TSTORMS WILL BE AFTER 18Z. KLGA FCSTER COMMENTS: VRB WINDS THROUGH EARLY AFTN ALONG STALLED BOUNDARY. TIMING OF WIND SHIFT/SEA BREEZE COULD BE OFF BY +/- AN HOUR OR TWO EARLY THIS AFTN. BEST CHC FOR SHOWERS/TSTMS WILL BE AFTER 17Z. KTEB FCSTER COMMENTS: BEST CHANCE FOR SHOWERS/TSTORMS WILL BE AFTER 18Z. KHPN FCSTER COMMENTS: BEST CHANCE FOR SHOWERS/TSTORMS WILL BE AFTER 18Z. KISP FCSTER COMMENTS: TIMING OF SEA BREEZE COULD BE OFF BY +/- AN HOUR. .OUTLOOK FOR 15Z WEDNESDAY THROUGH SAT... .WED-FRI...MVFR FOG/CIGS POSSIBLE DAILY 06Z-14Z. SCT TSTMS POSSIBLE DAILY MAINLY 18Z-04Z WITH MVFR CIGS AND IFR VSBY IN HVY RAIN AND GUSTY WINDS. OTHERWISE...MAINLY VFR. .SAT...MAINLY VFR. MVFR POSSIBLE IN SHOWERS. && .MARINE... SUB SCA CONDS THROUGH TONIGHT WITH GENERAL SW WINDS EXPECTED. WINDS ARE EXPECTED TO GRADUALLY INCREASE ON WEDNESDAY AHEAD OF AN APPROACHING PRE-FRONTAL TROUGH. THERE IS POTENTIAL FOR MARGINAL SCA WINDS ACROSS WESTERN OCEAN WATERS INTO ENTRANCE OF NYC HARBOR LATE WED WITH COASTAL JET. SOUTHERLY FLOW INCREASES ON WEDNESDAY AHEAD OF A SLOWLY MOVING COLD FRONT. THIS WILL BUILD SEAS ON THE OCEAN TO SCA LEVELS BY WEDNESDAY NIGHT...AND SCA CONDITIONS WILL CONTINUE THROUGH THURSDAY. OUTSIDE OF THE S SHORE BAYS...WHERE WINDS MAY REACH SCA LEVELS...THE REMAINING WATERS SHOULD REMAIN BELOW SCA LEVELS. HIGH PRES THEN BUILDS NORTH OF THE WATERS FRIDAY THROUGH THE WEEKEND. CONDITIONS ARE THEREFORE EXPECTED TO REMAIN BELOW SCA LEVELS. && .HYDROLOGY... SCATTERED SHOWERS/THUNDERSTORMS WILL PRODUCE LOCALLY HEAVY RAIN THIS AFTERNOON. AN ISOLATED FLASH FLOOD THREAT EXISTS WITH ANY TRAINING CONVECTION...MAINLY ALONG THE WESTERN SEABREEZE BOUNDARY AND/OR BACKDOOR COLD FRONT. THE FLASH FLOOD THREAT SHOULD INCREASE A BIT ON WEDNESDAY AFTERNOON ACROSS WESTERN PORTIONS OF THE AREA...AS HEAVY RAIN ENVIRONMENT BECOMES INCREASINGLY FAVORABLE AND CONVECTIVE COVERAGE IS EXPECTED TO INCREASE BETWEEN AN APPROACHING PRE-FRONTAL TROUGH AND SEABREEZE BOUNDARY. THE THREAT FOR FLASH FLOODING WILL EXIST IN THE PATH OF ANY TRAINING THUNDERSTORMS. THUNDERSTORMS WILL BE CAPABLE OF PRODUCING LOCALLY HEAVY RAINFALL WEDNESDAY THROUGH THURSDAY NIGHT ACROSS THE HSA. ALTHOUGH WIDESPREAD FLOODING IS NOT EXPECTED AT THIS TIME...FLASH FLOODING IS POSSIBLE WITH ANY TRAINING CONVECTION. RAINFALL IN EXCESS OF 2 INCHES IS POSSIBLE IN AN AREA IF THUNDERSTORMS TRAIN OVER THAT AREA FOR AN HOUR. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...NONE. && $$ SYNOPSIS...MPS/NV NEAR TERM...NV/DW SHORT TERM...NV LONG TERM...MPS AVIATION...BC MARINE...MPS/NV HYDROLOGY...MPS/NV
AREA FORECAST DISCUSSION
NWS NEW YORK NY
1059 AM EDT TUE JUL 9 2013 .SYNOPSIS... A WEAK FRONT ACROSS SOUTHERN CONNECTICUT WILL GRADUALLY RETURN NORTH THIS AFTERNOON. A WEAK TROUGH APPROACHES WEDNESDAY AFTERNOON...WITH A SLOWLY MOVING FRONTAL SYSTEM AFFECTING THE REGION THROUGH THE END OF THE WEEK. A COLD FRONT SLOWLY MOVES THROUGH THE REGION WEDNESDAY NIGHT THROUGH THURSDAY NIGHT...AND THEN STALLS OFFSHORE. HIGH PRESSURE THEN TRIES TO BUILD INTO THE REGION FOR THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... BASED ON LATEST RADAR IMAGERY AND OBS...A WEAK...DIFFUSE COLD FRONT APPEARS TO HAVE PUSHED ACROSS SRN CT...WITH LOCAL SEA- AND SOUND- BREEZES MAKING IT DIFFICULT TO PINPOINT THE EXACT LOCATION. LATEST HRRR MODEL TAKES BOUNDARY SLOWLY NORTH THIS AFTERNOON WITH CONVECTION BEING INITIATED ACROSS INTERIOR CT. ADDITIONAL SCT CONVECTION WILL LIKELY FIRE UP WITH AN APPROACHING SHORT WAVE TROF TO THE NORTH AND WEST OF NYC...BEFORE DISSIPATING NEAR THE COAST EARLY THIS EVE. SEABREEZE BOUNDARY IS ALSO ANOTHER POTENTIAL TRIGGER FOR CONVECTION. DUE TO WEAK STEERING WINDS FROM THE WEST AT 10 KT OR LESS...ANY CONVECTION WILL BE CAPABLE OF BRIEF HEAVY DOWNPOURS. WIND SHEAR IS WEAK WHICH DOES NOT SUPPORT ORGANIZED SEVERE CONVECTION. VERY WARM TEMPS CONTINUE WITH DEWPOINTS INCREASING A TAD AS COMPARED TO YESTERDAY. HEAT INDICES ACROSS NYC METRO AND INTERIOR SHOULD TOP OUT IN THE LOWER 90S ONCE AGAIN. A MODERATE RISK FOR RIP CURRENTS EXISTS AT THE ATLANTIC OCEAN BEACHES OF EASTERN LONG ISLAND TODAY. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/... WEAK VORTS WILL CONTINUE TO ROTATE THROUGH THE REGION TONIGHT INTO WEDNESDAY...AS A TROUGH DIGS INTO THE GREAT LAKES. AT THE SURFACE...THE BACK DOOR FRONT WILL GRADUALLY PUSH NORTH TONIGHT INTO WEDNESDAY. ON WEDNESDAY...A PRE-FRONTAL TROUGH WILL APPROACH THE REGION IN THE AFTERNOON AHEAD OF A DEVELOPING LOW PRESSURE SYSTEM NEAR HUDSON BAY. MAIN FOCUS FOR ANY SHRA/TSRA TONIGHT SHOULD BE NORTH OF THE REGION WITH LLJ FORCING AND THE NORTHWARD MOVING FRONTAL BOUNDARY OVERNIGHT. OTHERWISE...WITH DIMINISHING INSTABILITY THIS EVENING...WOULD EXPECTED ANY CONVECTION TO GRADUALLY WEAKEN. AN ISOLATED SHRA/TSRA IS POSSIBLE OVERNIGHT WITH INCREASING LLJ...MARGINAL INSTABILITY...AND WEAK VORT ACTIVITY...BUT MAINLY DRY. INCREASINGLY MOIST SOUTHERLY FLOW WILL BRIG POTENTIAL FOR PATCHY FOG AND STRATUS OVERNIGHT. POTENTIAL INCREASES FOR MORE WIDESPREAD CONVECTION ACROSS WESTERN ZONES...BETWEEN APPROACHING PRE-FRONTAL TROUGH AND SEABREEZE BOUNDARY...WEDNESDAY AFTERNOON WITH STRENGTHENING WIND FIELDS AND APPROACHING SHORTWAVE. SEVERE POTENTIAL WILL BE PREDICATED BY AMOUNT OF SUNSHINE...BUT WITH AN INCREASINGLY MOIST AIRMASS A MODERATELY UNSTABLE AIRMASS IS QUITE POSSIBLE IN THE ABOVE MENTIONED AREA. THE OTHER THREAT WILL BE FOR HEAVY RAIN AND POTENTIAL FLASH FLOODING WITH TRAINING CELLS ALONG S/N ORIENTED BOUNDARIES AS PWATS INCREASE TO AROUND 2" AND WARM CLOUD LAYER INCREASES. VERY WARM AND INCREASINGLY HUMID CONDITIONS ON WED...WITH TEMPS IN THE MID TO UPPER 80S NYC/NJ METRO AND INTERIOR...WITH LOWER TO MID 80S ALONG THE COAST IN SOUTHERLY SYNOPTIC FLOW. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... UNSETTLED WEATHER ON TAP FOR THE MIDDLE TO THE END OF THE WEEK AS LOW PRES TRACKING ACROSS EASTERN CANADA DRAGS A COLD THROUGH THE REGION ON THURSDAY. THE FIRST ROUND OF SHOWERS AND POSSIBLE THUNDERSTORMS WILL TAPER OFF IN THE FIRST HALF OF WEDNESDAY NIGHT....AND THEN ADDITIONAL SHOWERS AND POSSIBLE THUNDERSTORMS WILL DEVELOP ON THURSDAY AS WEAK LOW PRES DEVELOPS ALONG THE FRONT AND SLIDES THROUGH THE REGION. WITH PWATS AROUND 2"...CAN EXPECT HEAVY RAIN. SCATTERED TO NUMEROUS SHOWERS/TSTMS WILL IMPACT THE REGION THROUGHOUT THE DAY...TAPERING OFF LATE. BASED ON THE MODEST SW FLOW AND BUILDING SEAS...DANGEROUS RIPS APPEAR LIKELY WED AND THU AT THE OCEAN. COLD FRONT WILL BE THROUGH THE REGION THURSDAY NIGHT AND BECOMES NEARLY STATIONARY EAST OF THE AREA. H5 TROUGH/SHORTWAVE MOVES RIGHT OVER THE AREA ON FRIDAY AND THEN STALLS OUT OVER THE AREA. EVEN THOUGH HIGH PRES BUILDS IN AT THE SFC...WILL HAVE TO KEEP AT LEAST CHANCE POPS IN THE FORECAST FOR THE WEEKEND DUE TO THIS UPPER LEVEL SYSTEM OVER THE AREA. RETURN FLOW SETS UP BRINGING AN INCREASE IN THE HEAT AND HUMIDITY AGAIN ON MON. && .AVIATION /15Z TUESDAY THROUGH SATURDAY/... A TROUGH OF LOW PRESSURE WILL REMAIN OVER THE LOCAL AREA THROUGH TODAY. CONDITIONS WILL REMAIN PRIMARILY VFR TODAY. ONE EXCEPTION IS AT KGON WHERE A WEAK COLD FRONT HAS PUSHED SOUTH AND BROUGHT IFR CIGS. THESE CIGS HAVE BEGUN TO LIFT BUT MVFR/IFR AT TIMES IS STILL ANTICIPATED THROUGH THE AFTERNOON. WINDS WILL BE LIGHT AND MAY VARY TO E/ENE DIRECTION AT KGON/KBDR/KLGA/KISP THROUGH EARLY AFTERNOON. OTHERWISE...LIGHT SW WINDS INCREASE TO 10 AND 15 KT AFTER 18Z. EARLY AFTERNOON SEA BREEZES ARE EXPECTED. SHOWERS AND TSTORMS ARE POSSIBLE TODAY...BUT CONFIDENCE TOO LOW IN TIMING AND PLACEMENT TO INCLUDE IN TAFS. NY METRO ENHANCED AVIATION WEATHER SUPPORT... DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE) KEWR FCSTER COMMENTS: BEST CHANCE FOR SHOWERS/TSTORMS WILL BE AFTER 18Z. THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH IMPLIES SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD. KJFK FCSTER COMMENTS: TIMING OF SEA BREEZE COULD BE OFF BY +/- AN HOUR. BEST CHANCE FOR SHOWERS/TSTORMS WILL BE AFTER 18Z. KLGA FCSTER COMMENTS: VRB WINDS THROUGH EARLY AFTN ALONG STALLED BOUNDARY. TIMING OF WIND SHIFT/SEA BREEZE COULD BE OFF BY +/- AN HOUR OR TWO EARLY THIS AFTN. BEST CHC FOR SHOWERS/TSTMS WILL BE AFTER 17Z. KTEB FCSTER COMMENTS: BEST CHANCE FOR SHOWERS/TSTORMS WILL BE AFTER 18Z. KHPN FCSTER COMMENTS: BEST CHANCE FOR SHOWERS/TSTORMS WILL BE AFTER 18Z. KISP FCSTER COMMENTS: TIMING OF SEA BREEZE COULD BE OFF BY +/- AN HOUR. .OUTLOOK FOR 15Z WEDNESDAY THROUGH SAT... .WED-FRI...MVFR FOG/CIGS POSSIBLE DAILY 06Z-14Z. SCT TSTMS POSSIBLE DAILY MAINLY 18Z-04Z WITH MVFR CIGS AND IFR VSBY IN HVY RAIN AND GUSTY WINDS. OTHERWISE...MAINLY VFR. .SAT...MAINLY VFR. MVFR POSSIBLE IN SHOWERS. && .MARINE... SUB SCA CONDS THROUGH TONIGHT WITH GENERAL SW WINDS EXPECTED. WINDS ARE EXPECTED TO GRADUALLY INCREASE ON WEDNESDAY AHEAD OF AN APPROACHING PRE-FRONTAL TROUGH. THERE IS POTENTIAL FOR MARGINAL SCA WINDS ACROSS WESTERN OCEAN WATERS INTO ENTRANCE OF NYC HARBOR LATE WED WITH COASTAL JET. SOUTHERLY FLOW INCREASES ON WEDNESDAY AHEAD OF A SLOWLY MOVING COLD FRONT. THIS WILL BUILD SEAS ON THE OCEAN TO SCA LEVELS BY WEDNESDAY NIGHT...AND SCA CONDITIONS WILL CONTINUE THROUGH THURSDAY. OUTSIDE OF THE S SHORE BAYS...WHERE WINDS MAY REACH SCA LEVELS...THE REMAINING WATERS SHOULD REMAIN BELOW SCA LEVELS. HIGH PRES THEN BUILDS NORTH OF THE WATERS FRIDAY THROUGH THE WEEKEND. CONDITIONS ARE THEREFORE EXPECTED TO REMAIN BELOW SCA LEVELS. && .HYDROLOGY... SCATTERED SHOWERS/THUNDERSTORMS WILL PRODUCE LOCALLY HEAVY RAIN THIS AFTERNOON. AN ISOLATED FLASH FLOOD THREAT EXISTS WITH ANY TRAINING CONVECTION...MAINLY ALONG THE WESTERN SEABREEZE BOUNDARY AND/OR BACKDOOR COLD FRONT. THE FLASH FLOOD THREAT SHOULD INCREASE A BIT ON WEDNESDAY AFTERNOON ACROSS WESTERN PORTIONS OF THE AREA...AS HEAVY RAIN ENVIRONMENT BECOMES INCREASINGLY FAVORABLE AND CONVECTIVE COVERAGE IS EXPECTED TO INCREASE BETWEEN AN APPROACHING PRE-FRONTAL TROUGH AND SEABREEZE BOUNDARY. THE THREAT FOR FLASH FLOODING WILL EXIST IN THE PATH OF ANY TRAINING THUNDERSTORMS. THUNDERSTORMS WILL BE CAPABLE OF PRODUCING LOCALLY HEAVY RAINFALL WEDNESDAY THROUGH THURSDAY NIGHT ACROSS THE HSA. ALTHOUGH WIDESPREAD FLOODING IS NOT EXPECTED AT THIS TIME...FLASH FLOODING IS POSSIBLE WITH ANY TRAINING CONVECTION. RAINFALL IN EXCESS OF 2 INCHES IS POSSIBLE IN AN AREA IF THUNDERSTORMS TRAIN OVER THAT AREA FOR AN HOUR. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...NONE. && $$ SYNOPSIS...MPS/NV NEAR TERM...NV/DW SHORT TERM...NV LONG TERM...MPS AVIATION...BC MARINE...MPS/NV HYDROLOGY...MPS/NV
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
1125 AM EDT TUE JUL 9 2013 .UPDATE... 15Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS AN UNAMPLIFIED UPPER LEVEL PATTERN WITH THE MAIN NORTHERN STREAM FLOW ALIGNED ZONALLY OVER THE U.S/CANADIAN BORDER. TO THE SOUTH OF THE NORTHERN STREAM WE FIND A BROAD EXPANSE OF UPPER LEVEL RIDGING IN PLACE ACROSS MUCH OF THE SOUTHERN TIER OF THE CONUS. ONE OTHER FEATURE OF NOTE IS A TUTT FEATURE/UPPER LOW SLOWLY MIGRATING WESTWARD FROM THE BAHAMAS TOWARD THE SOUTHERN FL PENINSULA. THIS TUTT FEATURE MAY BRING SOME ENHANCED RAIN CHANCES TO THE AREA ON WEDNESDAY...ESPECIALLY FOR THE SOUTHERN HALF OF THE PENINSULA...BUT OVERALL WILL BE IN A WEAKENING PHASE IN TERMS OF ITS NEGATIVE THERMAL ANOMALY...AND THIS SHOULD LIMIT THE OVERALL POSITIVE INSTABILITY IMPACT THAT TUTT CELLS CAN HAVE TOWARD DIURNAL CONVECTION THIS TIME OF YEAR. AT THE SURFACE...HIGH PRESSURE IS ALIGNED FROM OFF THE GA/SC COAST WESTWARD ALONG OR JUST NORTH OF THE I-10 CORRIDOR. WE FIND OUR FORECAST AREA SITUATED BETWEEN THIS RIDGE AXIS AND A WEAK INVERTED TROUGH ALONG THE FL SE COAST. THIS TROUGH IS REALLY JUST THE SURFACE REFLECTION OF THE TUTT...AND IS PROGGED BY THE LATEST NAM/GFS AND LOCAL HI-RES MODELS TO MIGRATE IN ADVANCE OF THE UPPER LEVEL FEATURE ACROSS TO THE SOUTHWEST PENINSULA COAST BY THIS EVENING. THE ADDED LOW LEVEL FOCUS ASSOCIATED WITH THIS WEAK TROUGH MAY HELP TO ENHANCE THE DIURNAL THUNDERSTORM ACTIVITY FOR OUR SOUTHERN COASTAL ZONES LATER THIS AFTERNOON. REST OF TODAY... ANOTHER COUPLE HOURS OF GENERALLY DRY CONDITIONS FOR OUR ZONES BEFORE THE DIURNAL CONVECTION BEGINS TO FOCUS. SIMILAR TO PREVIOUS DAYS...RAIN CHANCES...ESPECIALLY NEAR THE COAST WILL PEAK DURING THE LATE AFTERNOON/EVENING HOURS. 12Z KTBW SOUNDING WAS A BIT ON THE DRY SIDE...AND WOULD NOT BE AN UNFAVORABLE PROFILE TO SUPPORT A FEW WET-MICROBURSTS WITH ANY STRONGER LATE DAY STORMS. HOWEVER...NUMERICAL GUIDANCE DOES INDICATE THAT DRIEST OF THE MID-LEVEL AIR WILL MODIFY SOMEWHAT BY THIS EVENING AND DECREASE THIS THETA-E DIFFERENCE FROM THE SURFACE. THE BEST POSITIVE MOISTURE ADVECTION WILL CERTAINLY BE DOWN TOWARD FT. MYERS. THE NET RESULT OF THIS WOULD LIKELY TO FURTHER ENHANCE THE STORM COVERAGE SOUTH OF TAMPA BAY...BUT LIMIT THE POTENTIAL WIND IMPACTS FROM ANY STRONGER STORMS. FROM TAMPA BAY NORTHWARD...THE DRIER COLUMN SHOULD KEEP THE ACTIVITY MORE SCATTERED...BUT ANY STRONGER STORMS WILL NEED TO BE WATCHED CLOSELY FOR STRONG WIND GUST POTENTIAL. LINGERING EVENING STORMS WILL SHIFT OFFSHORE AND WEAKEN DURING THE MID/LATE EVENING HOURS. THE WEAK UPPER LEVEL SUPPORT FROM THE TUTT IS LIKELY TO AID ANY TYPICAL NOCTURNAL LAND BREEZE CONVECTION OVER THE WATER. HAVE INCREASED POPS AFTER MIDNIGHT AWAY FROM THE COAST INTO THE CHANCE 30-40% RANGE. JUST SOMETHING TO KEEP IN MIND FOR THOSE PLANNING TO BOAT EARLY IN THE MORNING. && .AVIATION... MAINLY VFR CONDITIONS BUT WITH A CHANCE OF TSRA IN THE AFTERNOON. WILL HANDLE WITH VCNTY REMARK FOR NOW. EASTERLY WINDS SHIFT TO ONSHORE IN THE AFTERNOON ALONG THE COAST. && .MARINE... A FAIRLY WEAK PRESSURE PATTERN IS EXPECTED ACROSS THE WATERS THROUGH THE FORECAST PERIOD...WITH THE ONLY POTENTIAL CAVEAT BEING THE TRACK OF TROPICAL STORM CHANTAL OR IT/S REMNANT LOW OVER THE WEEKEND AND INTO EARLY NEXT WEEK. THE LATEST FORECAST FROM THE NATIONAL HURRICANE CENTER CONTINUES TO SHOW THE SYSTEM MOVING NORTHWARD WELL OFF THE EAST FLORIDA COAST...WHICH WOULD RESULT IN LITTLE IF ANY IMPACT ON THE LOCAL MARINE AREA. AS A RESULT...WINDS AND SEAS ARE EXPECTED TO REMAIN BELOW HEADLINE THRESHOLDS THROUGH THE FORECAST PERIOD. && .PRELIMINARY POINT TEMPS/POPS... TPA 91 75 90 76 / 40 30 40 30 FMY 91 72 91 74 / 50 20 50 30 GIF 91 72 91 74 / 30 10 30 20 SRQ 91 73 89 74 / 40 30 40 20 BKV 93 70 91 71 / 40 20 40 30 SPG 92 77 90 77 / 40 30 40 20 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...NONE. GULF WATERS...NONE. && $$ UPDATE...MROCZKA AVIATION...RUDE
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
926 AM CDT TUE JUL 9 2013 .DISCUSSION... 340 AM CDT SEVERE WEATHER AND HEAVY RAIN POTENTIAL THROUGH TONIGHT WAS WHAT MUCH OF THE ANALYSIS TIME WAS SPENT ON THIS MORNING. WHAT MAINLY WAS TRYING TO DO WAS LOCK DOWN A TIMING FOR AN IMPROVED SEVERE WEATHER THREAT /MID-AFTERNOON THROUGH EARLY OVERNIGHT THOUGH AIR MASS CAN ALLOW FOR ISOLATED SEVERE ANYTIME/...AND WHAT MAIN THREATS WOULD BE /WIND AND HEAVY RAIN/. OVERALL NO MAJOR CHANGES MADE TO THE FORECAST...JUST INCREASING POPS IN THOSE MOST FAVORED TIMES...RE-ORIENTING POPS SOME...AND REFINING RAINFALL AMOUNT FORECASTS. SYNOPSIS...A VERY SOUPY AIR MASS IS ENTRENCHED IN THE REGION THIS MORNING WITH MID 70S DEW POINTS ACROSS THE FORECAST AREA AND PWATS ON LAST EVES REGIONAL RAOBS AND EARLY MORNING OBJECTIVE ANALYSIS BEING AROUND 2 INCHES. NUMEROUS SHORT WAVE IMPULSES...MANY WITH ASSOCIATED CLUSTERS OF CONVECTION...ARE FOUND UPSTREAM ACROSS THE HIGH PLAINS AND OVER THE WESTERN CORN BELT ON GOES WATER VAPOR IMAGERY. THE PRIMARY UPPER LEVEL SHORT WAVE TROUGH WILL BE DIGGING INTO EASTERN MT SOON AFTER DAYBREAK AND WILL BE THE RESPONSIBLE PARTY FOR ENDING THIS MOIST AIR MASS...AT LEAST TEMPORARILY BY LATER WED. AT THE SURFACE A FAIRLY DIFFUSE GRADIENT EXISTS EARLY TODAY WITH A WEAK STATIONARY BOUNDARY NEAR THE STATE LINE. THE WEAK FLOW HAS ALLOWED FOR LOW CLOUDS AND FOG TO BE EXPANDING THEIR WAY SOUTHWARD DOWN LAKE MI AIDED BY AMBIENT DEW POINTS EXCEEDING THE WATER TEMPS BY SEVERAL DEGREES. THE PRIMARY SURFACE FRONT IS TAKING SHAPE ACROSS THE HIGH PLAINS AND WILL DEVELOP INTO A COOL FRONT LATER TODAY AS SURFACE CYCLOGENESIS OCCURS THROUGH NORTHERN MN INTO WESTERN ONTARIO BY THIS EVE. THIS FRONT WILL MOVE INTO THE FORECAST AREA LATE TONIGHT INTO EARLY WED MORNING. MULTIPLE ROUNDS OF CONVECTION ARE LIKELY AHEAD OF THIS. MODEL PREFERENCE...THE RAP AND HRRR GUIDANCE HAVE A GOOD REPRESENTATION OF ONGOING CONVECTION. THESE HAVE THE SUPPORT OF SEVERAL OTHER CONVECTIVE ALLOWING MODELS AND HAVE BEEN GUIDED ON THROUGH MID-AFTERNOON. AFTERWORDS HAVE LEANED TOWARD THE SLIGHTLY SLOWER 09.00 NAM THAN GFS. THIS MORNING...REMNANT MCV/SHORT WAVE ENTERING WESTERN IL EARLY THIS MORNING HAS BEGUN TO INCREASE RADAR ECHOES ACROSS CENTRAL IL AND THIS TREND IS LIKELY TO CONTINUE WITH SCATTERED CONVECTION FAVORED DUE TO MODERATE TO HIGH ELEVATED INSTABILITY. NOT A PARTICULARLY STRONG LOW-LEVEL JET OR ONE WITH HUGE MOISTURE TRANSPORT THIS MORNING...DUE TO STILL BEING A GOOD DISTANCE AHEAD OF MID-LEVEL HEIGHT FALLS. SO MORNING SCATTERED TO NUMEROUS SHOWERS/STORMS ACROSS CENTRAL IL MAY STRUGGLE TO PROGRESS NORTH/NORTHEAST AT LEAST AT ANY GOOD CLIP OF SPEED. THUS ROCKFORD TO CHICAGO HAVE POPS ONLY AT THE CHANCE LEVEL...AND MORE SO BASED ON ISOLATED CELLS DEVELOPING IN THE BROAD WAA AND HIGH PWAT REGIME. WITH SUCH HIGH PWATS AS YESTERDAY MORNING SHOWED...LOCALLY HEAVY RAINFALL WOULD BE THE PRIMARILY ASPECT TO KEEP AN EYE ON WITH THESE MORNING AND EARLY AFTERNOON STORMS. AS FOR EARLY MORNING FOG/STRATUS THAT HAS BEEN DEVELOPING IN PLACES...ONSHORE FLOW MAY FAVOR PATCHES OF THIS TO CONTINUE THROUGH MID OR EVEN LATE MORNING ACROSS NORTHEAST IL AND FAR NORTHWEST IN...STUNTING A TEMPERATURE CLIMB INITIALLY. OTHERWISE THIS LOOKS LIKE IT SHOULD BEGIN DISSIPATING/RETREATING NORTH AFTER THAT TIME. CONFIDENCE...HIGH. THIS AFTERNOON THROUGH TONIGHT...THE END OF THE RAP RUN AGREES CLOSELY WITH THE NAM IN TAKING THE SHORT WAVES AND ASSOCIATED 500 AND 700MB SPEED MAXS ACROSS THE DAKOTAS AND NORTHERN NEBRASKA EARLY THIS MORNING AND TRACKING THAT EAST INTO SOUTHERN WI AND NORTHERN IL BY MID TO LATE AFTERNOON. ON THE SYNOPTIC SCALE AT THAT TIME...THE LOW-LEVEL JET AND MOISTURE TRANSPORT WILL ALSO BE ON THE EXPANSE FROM MO INTO EASTERN IA/WESTERN IL. MIXED LAYER INSTABILITY WILL BE HIGH OVER THIS AREA INCLUDING THE WESTERN FORECAST AREA GIVEN TEMPS IN THE UPPER 80S TO LOWER 90S. WHILE SOME FORM OF MCS OR MULTIPLE CLUSTERS ARE PROBABLE TO BE MOVING EASTWARD OVER SOUTHERN WI/FAR NORTHERN IL DURING THE AFTERNOON WITH THE SHORT WAVES...DEVELOPMENT IS FAVORED TO WORK ITS WAY SOUTH AND BACK TO THE SOUTHWEST FROM THERE IN THE MOIST UNSTABLE AIR MASS DURING THE MID-AFTERNOON. DEEP LAYER SHEAR IS ANTICIPATED TO BE INCREASING TO AROUND 30-35 KT BY LATE AFTERNOON WITH ORGANIZED STORMS EXPECTED TO BE ALL WORKING THEIR WAY EASTWARD. AS THE PRIMARY UPPER TROUGH APPROACHES THIS EVENING...LARGER SCALE ASCENT AND FORCING IS LIKELY TO CONTINUE REGIONAL DEVELOPMENT OF STORMS NEAR AND AHEAD OF THE SURFACE FRONT. SO WHILE THERE LOOKS TO BE TWO PRIMARY FOCUSES FOR STORMS THIS AFTERNOON INTO TONIGHT...THERE IS NOT REALLY ANTICIPATED TO BE MUCH OF A BREAK AND THE HIGH PWAT AND UNSTABLE AIR SHOULD ALLOW FOR PLENTY OF COVERAGE. THAT COVERAGE MAY INITIALLY BE A LITTLE LIMITED DEPENDING ON DEBRIS CLOUD COVER BUT IS ANTICIPATED TO BE ITS HIGHEST LATER THIS AFTERNOON THROUGH EARLY OVERNIGHT. THE MOST FAVORED MODE FOR STORMS IS MULTICELL AND SEGMENTS CAPABLE OF SCATTERED DAMAGING WINDS...ESPECIALLY AS THE STRONGER MID-LEVEL JET OVERRIDES THE FRONT THIS EVENING INTO EARLY OVERNIGHT. SOME DEVELOPMENT THIS AFTERNOON THROUGH MID-EVE HAS THE POTENTIAL TO BE SUPERCELLULAR. THE LOW-LEVEL SHEAR IS FAIRLY ANEMIC MUCH OF THIS AFTERNOON /AOB 10 KT/ BUT QUICKLY INCREASES LATE INTO EARLY THIS EVE DUE TO THE DEEPENING LOW AND INCREASING LLJ. THIS WILL HELP FAVOR COLD POOL SUSTAINABILITY AND DOES PRESENT AT LEAST SOME TORNADO THREAT...ALTHOUGH IT LOOKS LIKE SURFACE WINDS MAY BE BACKED MORE TO THE WEST OF THE FORECAST AREA IMMEDIATELY AHEAD OF A SUBTLE SECONDARY SURFACE LOW MOVING UP THE FRONT. SO THE PRIMARY THREAT WILL REMAIN WIND AND OF COURSE HEAVY RAIN WITH EXTREMELY EFFICIENT RAIN PRODUCTION WILL OCCUR IN ANY STORMS TODAY AND TONIGHT. EVEN THOUGH FORWARD PROPAGATION OF STORMS SHOULD BE ON THE INCREASE TONIGHT...SO WILL DEEP MOISTURE REPLENISHMENT AND SIMPLY PUT THE ABSOLUTE MOISTURE IS SO HIGH IT WONT TAKE MUCH TO GET HIGH RAINFALL RATES SUCH AS WE SAW YESTERDAY MORNING. THERE WILL LIKELY BE SWATHS OF RAINFALL IN EXCESS OF ONE TO TWO INCHES ACROSS THE IMMEDIATE REGION...BUT WHERE EXACTLY THEY OCCUR IS TOO CHALLENGING TO LOCK DOWN. DEBATED ON A FLASH FLOOD WATCH BUT FEEL THE THREAT IS TOO LOCALIZED AT THIS TIME FOR A WATCH. CONFIDENCE...MEDIUM. WEDNESDAY...ONGOING SCATTERED SHOWERS AND STORMS ARE POSSIBLE ACROSS MAINLY THE SOUTHERN AND EASTERN FORECAST AREA IN THE MORNING WITH STILL AT LEAST SOME HEAVY RAIN THREAT. WARM 850-925MB AIR BEHIND THE SURFACE WIND SHIFT WILL STILL FAVORED HIGHS IN THE MID TO POSSIBLY EVEN UPPER 80S IN THE SOUTH. DRIER AIR WILL GRADUALLY FILTER IN DURING THE LATER AFTERNOON AND NIGHT PER GUIDANCE. CONFIDENCE...HIGH. THURSDAY THROUGH MONDAY...PRIMARILY DRY WEATHER IS EXPECTED OVER THE AREA ALTHOUGH THE TREND IN BOTH THE EC AND GFS THEIR LAST MULTIPLE RUNS SUPPORTS WARMER TEMPERATURES THIS WEEKEND WITH MID AND MAYBE EVEN UPPER 80S SEEN. HAVE COLLABORATED AND LEANED TOWARD THE WARMER MEX GUIDANCE. THE PATTERN STILL APPEARS BLOCKED JUST WITH THE AREA MORE UNDER THE INFLUENCE OF THE UPPER RIDGE TO THE WEST. MTF && .HYDROLOGY... 410 AM CDT THE VERY MOIST AIR MASS WILL SUPPORT EFFICIENT RAINFALL PRODUCTION FROM ANY THUNDERSTORMS TODAY AND TONIGHT. THIS MAY PRESENT FLASH FLOODING ESPECIALLY ON THE LOCAL LEVEL AS OPPOSED TO ANY WIDESPREAD THREAT. THAT AND THE FACT THERE IS NOT A GREAT SET UP FOR TRUE TRAINING STORMS IS WHY NO FLASH FLOOD WATCH AT THIS TIME. HOWEVER...IF ANY STORMS ARE IN A PARTICULARLY VULNERABLE AREA...SUCH AS A METRO OR A QUICK-RESPONDING WATERSHED...IT COULD BE TROUBLE. THESE TYPE OF HIGH RATES WERE ALREADY SEEN YESTERDAY MORNING WITH A NARROW SWATH OF ONE AND A HALF TO ESTIMATED THREE PLUS INCHES OF RAIN SEEN FROM RE-FIRING STORMS IN THE WEST CHICAGO METRO. HIGH RESOLUTION MODEL GUIDANCE INDICATES SUCH SWATHS ARE PROBABLE IN THE REGION THIS AFTERNOON INTO TONIGHT ALTHOUGH WHERE IS STILL UNCERTAIN. THE GENERAL RAINFALL FORECAST IS FOR MOST AREAS TO SEE AROUND AN INCH OR A LITTLE OVER BY WEDNESDAY MORNING. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 14Z... * LIGHT SOUTHWEST WINDS EXPECTED TO CONTINUE WITH NORTHEAST WINDS OFF THE LAKE EXPECTED TO STAY EAST OF THE TERMINALS THIS MORNING. * SHRA/TSRA CHANCES INCREASING FROM LATE MORNING THROUGH THE AFTERNOON. MDB //DISCUSSION...UPDATED 14Z... MADE SOME ADJUSTMENTS TO THE WINDS THIS MORNING TO BRING THEM SOUTHWESTERLY AT ORD/MDW/GYY. A LIGHT NORTHEAST WIND IS OCCURRING RIGHT ALONG THE LAKESHORE BUT HAS NOT MADE MUCH IF ANY PROGRESS INLAND. WITH INCREASING CLOUD COVER SLOWING THE HEATING OVER LAND COMPARED TO OVER THE LAKE...PRESSURE FALLS STARTING TO SPREAD IN AND A SLOWLY INCREASING PRESSURE GRADIENT OPTED TO KEEP WINDS LIGHT FROM THE SOUTHWEST. NEXT CONCERN IS SHOWERS AND THUNDERSTORMS STRETCHING FROM NEAR VYS TO SFY TO PVB. THIS ACTIVITY CONTINUES TO MOVE EASTWARD WITH COVERAGE INCREASING SOMEWHAT. OTHERWISE SCATTERED VERY LIGHT SHOWERS DO RUN ALONG A LINE FROM GYY WEST TO VYS. RFD WILL LIKELY HAVE PERIODIC TSRA ARRIVE IN THE NEXT HOUR OR SO BUT COVERAGE TO THE EAST IS SOMEWHAT IN QUESTION. IT APPEARS THAT THE INITIAL ACTIVITY WILL STAY JUST SOUTH OF ORD/MDW AND GRAZE GYY BUT ACTIVITY MAY BUILD AND INCREASE IN COVERAGE AS THE ENTIRE COMPLEX WORKS EAST. BARRING MUCH NEW DEVELOPMENT EASTWARD THE CURRENT ACTIVITY WOULD LIKELY WORK INTO THE CHI AREA TOWARD 17Z. MAY NEED TO SPEED THIS UP IN THE TAFS AS THE TRENDS BECOME MORE CLEAR. MDB FROM 12Z... RELATIVELY QUIET ACROSS THE TERMINALS THIS MORNING WHILE SOME FOG/HAZE REMAINS OVERHEAD...BUT WITH THE MORE DENSE FOG REMAINING AWAY FROM THE TERMINALS AT THIS TIME. ANY FOG THIS MORNING SHOULD QUICKLY DISSIPATE OVER THE NEXT HOUR WITH ANY THREAT OF LOWER VIS/CEILINGS COMING SOUTH DOWN THE LAKE REMAINING LOW AT THIS TIME. ALTHOUGH THIS AREA IS STILL SLOWLY MOVING SOUTH DOWN THE LAKE...VEERING WINDS AND SHOULD HELP LIMIT THIS SOUTHWARD MOMENTUM KEEPING THIS FOG NORTH OF THE TERMINALS. THEN SHIFT GEARS TO REDEVELOPMENT OF SHOWERS/TS LATER THIS MORNING...AS PRECIP DEVELOPS OUT AHEAD OF AN APPROACHING MID LEVEL DISTURBANCE. AS THIS DISTURBANCE DRAWS NEAR...EXPECT CURRENT THUNDERSTORMS OVER IOWA AS WELL AS OTHER DEVELOPMENT TO MOVE ACROSS THROUGH NORTHERN ILLINOIS/NORTHWEST INDIANA BY MID DAY WITH SOME UPWARD GROWTH IN COVERAGE AND INTENSITY EXPECTED INTO THE EARLY AFTERNOON. DO EXPECT A BRIEF LULL IN THE ACTIVITY AFTER THIS INITIAL PRECIP MOVES THROUGH...BUT WITH DEVELOPMENT STILL POSSIBLE GOING INTO THE EARLY EVENING. STILL MONITORING THE POTENTIAL FOR A MORE WIDESPREAD AREA OF THUNDERSTORMS TO MOVE ACROSS THE TERMINALS LATER THIS EVENING AND OVERNIGHT. ALTHOUGH IT STILL SEEMS FAVORABLE FOR THIS TO MOVE ACROSS THE TERMINALS...WILL NEED TO MONITOR LATER TRENDS AFTER THIS INITIAL PRECIP THIS AFTERNOON MOVES THROUGH. WINDS REMAIN LIGHT/VARIABLE THIS MORNING BUT ANTICIPATE A TREND TOWARDS AN EAST NORTHEAST WIND OVER THE NEXT SEVERAL HOURS. WINDS ALONG THE LAKE ARE ALREADY THIS EASTERLY COMPONENT AND WITH THE SUN RISING COINCIDING WITH A WEAK GRADIENT...FEEL THAT IT WONT TAKE MUCH FOR THIS NORTHEAST WIND TO DEVELOP OVER ORD/MDW/GYY THIS MORNING. THEN EXPECT A SLOW TREND TOWARDS THE SOUTHEAST AND EVENTUALLY SOUTH THIS AFTERNOON/EVENING...BEFORE WINDS CONTINUE TO VEER TO THE WEST OVERNIGHT. RODRIGUEZ //ORD AND MDW CONFIDENCE...UPDATED 14Z... * MEDIUM-HIGH CONFIDENCE IN LIGHT SOUTHWEST WINDS PREVAILING THROUGH THE MORNING. * MEDIUM-HIGH CONFIDENCE IN SHRA/TSRA AFFECTING THE TERMINALS...MEDIUM CONFIDENCE IN TIMING. MDB //OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z... WEDNESDAY NIGHT...VFR. THURSDAY...VFR. FRIDAY...VFR. SATURDAY...VFR. SUNDAY...VFR. MONDAY...VFR. RODRIGUEZ && .MARINE... 427 AM CDT MAIN FORECAST CONCERN IN THE NEAR TERM IS FOR AREAS ACROSS THE NORTHERN TWO THIRDS OF THE LAKE...WHERE DENSE FOG HAS SETTLED IN. EXPECT THIS FOG TO PERSIST AT LEAST THROUGH THE AFTERNOON WITH CURRENT THINKING THAT THIS FOG WILL CHURN UP WITH APPROACHING PRECIP. ALTHOUGH CONFIDENCE IS LOW...AND ITS POSSIBLE THE CURRENT DENSE FOG ADVISORY IN PLACE THROUGH THE AFTERNOON COULD NEED TO BE EXTENDED THROUGH THE EVENING. THERE IS ALSO POTENTIAL FOR THE MORE DENSE FOG TO PUSH FURTHER DOWN THE LAKE EARLY THIS MORNING...BEFORE WINDS BEGIN TO SHIFT AND BRING A STOP TO THIS SOUTHWARD MOVING AREA OF FOG. CURRENT LIGHT NORTHERLY WINDS IN PLACE ACROSS THE LAKE WILL TURN MORE SOUTHERLY THROUGHOUT TODAY AS THE NEXT SYSTEM APPROACHES FROM THE WEST. AS THIS SYSTEM THEN PROGRESSES ACROSS THE LAKE TONIGHT...EXPECT SOUTHWEST WINDS TO BECOME MORE WESTERLY WHILE INCREASING MORE TOWARDS THE 10 TO 20 KT RANGE. THEN AS HIGH PRESSURE SLOWLY BUILDS EAST TOWARDS THE LAKE...EXPECT GENERALLY NORTHERLY WINDS THROUGH THE REST OF THE WORK WEEK. RODRIGUEZ && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...DENSE FOG ADVISORY...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565- LMZ567-LMZ669-LMZ671-LMZ673-LMZ868-LMZ870-LMZ872-LMZ874 UNTIL 3 PM TUESDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
705 AM CDT TUE JUL 9 2013 .DISCUSSION... 340 AM CDT SEVERE WEATHER AND HEAVY RAIN POTENTIAL THROUGH TONIGHT WAS WHAT MUCH OF THE ANALYSIS TIME WAS SPENT ON THIS MORNING. WHAT MAINLY WAS TRYING TO DO WAS LOCK DOWN A TIMING FOR AN IMPROVED SEVERE WEATHER THREAT /MID-AFTERNOON THROUGH EARLY OVERNIGHT THOUGH AIR MASS CAN ALLOW FOR ISOLATED SEVERE ANYTIME/...AND WHAT MAIN THREATS WOULD BE /WIND AND HEAVY RAIN/. OVERALL NO MAJOR CHANGES MADE TO THE FORECAST...JUST INCREASING POPS IN THOSE MOST FAVORED TIMES...RE-ORIENTING POPS SOME...AND REFINING RAINFALL AMOUNT FORECASTS. SYNOPSIS...A VERY SOUPY AIR MASS IS ENTRENCHED IN THE REGION THIS MORNING WITH MID 70S DEW POINTS ACROSS THE FORECAST AREA AND PWATS ON LAST EVES REGIONAL RAOBS AND EARLY MORNING OBJECTIVE ANALYSIS BEING AROUND 2 INCHES. NUMEROUS SHORT WAVE IMPULSES...MANY WITH ASSOCIATED CLUSTERS OF CONVECTION...ARE FOUND UPSTREAM ACROSS THE HIGH PLAINS AND OVER THE WESTERN CORN BELT ON GOES WATER VAPOR IMAGERY. THE PRIMARY UPPER LEVEL SHORT WAVE TROUGH WILL BE DIGGING INTO EASTERN MT SOON AFTER DAYBREAK AND WILL BE THE RESPONSIBLE PARTY FOR ENDING THIS MOIST AIR MASS...AT LEAST TEMPORARILY BY LATER WED. AT THE SURFACE A FAIRLY DIFFUSE GRADIENT EXISTS EARLY TODAY WITH A WEAK STATIONARY BOUNDARY NEAR THE STATE LINE. THE WEAK FLOW HAS ALLOWED FOR LOW CLOUDS AND FOG TO BE EXPANDING THEIR WAY SOUTHWARD DOWN LAKE MI AIDED BY AMBIENT DEW POINTS EXCEEDING THE WATER TEMPS BY SEVERAL DEGREES. THE PRIMARY SURFACE FRONT IS TAKING SHAPE ACROSS THE HIGH PLAINS AND WILL DEVELOP INTO A COOL FRONT LATER TODAY AS SURFACE CYCLOGENESIS OCCURS THROUGH NORTHERN MN INTO WESTERN ONTARIO BY THIS EVE. THIS FRONT WILL MOVE INTO THE FORECAST AREA LATE TONIGHT INTO EARLY WED MORNING. MULTIPLE ROUNDS OF CONVECTION ARE LIKELY AHEAD OF THIS. MODEL PREFERENCE...THE RAP AND HRRR GUIDANCE HAVE A GOOD REPRESENTATION OF ONGOING CONVECTION. THESE HAVE THE SUPPORT OF SEVERAL OTHER CONVECTIVE ALLOWING MODELS AND HAVE BEEN GUIDED ON THROUGH MID-AFTERNOON. AFTERWORDS HAVE LEANED TOWARD THE SLIGHTLY SLOWER 09.00 NAM THAN GFS. THIS MORNING...REMNANT MCV/SHORT WAVE ENTERING WESTERN IL EARLY THIS MORNING HAS BEGUN TO INCREASE RADAR ECHOES ACROSS CENTRAL IL AND THIS TREND IS LIKELY TO CONTINUE WITH SCATTERED CONVECTION FAVORED DUE TO MODERATE TO HIGH ELEVATED INSTABILITY. NOT A PARTICULARLY STRONG LOW-LEVEL JET OR ONE WITH HUGE MOISTURE TRANSPORT THIS MORNING...DUE TO STILL BEING A GOOD DISTANCE AHEAD OF MID-LEVEL HEIGHT FALLS. SO MORNING SCATTERED TO NUMEROUS SHOWERS/STORMS ACROSS CENTRAL IL MAY STRUGGLE TO PROGRESS NORTH/NORTHEAST AT LEAST AT ANY GOOD CLIP OF SPEED. THUS ROCKFORD TO CHICAGO HAVE POPS ONLY AT THE CHANCE LEVEL...AND MORE SO BASED ON ISOLATED CELLS DEVELOPING IN THE BROAD WAA AND HIGH PWAT REGIME. WITH SUCH HIGH PWATS AS YESTERDAY MORNING SHOWED...LOCALLY HEAVY RAINFALL WOULD BE THE PRIMARILY ASPECT TO KEEP AN EYE ON WITH THESE MORNING AND EARLY AFTERNOON STORMS. AS FOR EARLY MORNING FOG/STRATUS THAT HAS BEEN DEVELOPING IN PLACES...ONSHORE FLOW MAY FAVOR PATCHES OF THIS TO CONTINUE THROUGH MID OR EVEN LATE MORNING ACROSS NORTHEAST IL AND FAR NORTHWEST IN...STUNTING A TEMPERATURE CLIMB INITIALLY. OTHERWISE THIS LOOKS LIKE IT SHOULD BEGIN DISSIPATING/RETREATING NORTH AFTER THAT TIME. CONFIDENCE...HIGH. THIS AFTERNOON THROUGH TONIGHT...THE END OF THE RAP RUN AGREES CLOSELY WITH THE NAM IN TAKING THE SHORT WAVES AND ASSOCIATED 500 AND 700MB SPEED MAXS ACROSS THE DAKOTAS AND NORTHERN NEBRASKA EARLY THIS MORNING AND TRACKING THAT EAST INTO SOUTHERN WI AND NORTHERN IL BY MID TO LATE AFTERNOON. ON THE SYNOPTIC SCALE AT THAT TIME...THE LOW-LEVEL JET AND MOISTURE TRANSPORT WILL ALSO BE ON THE EXPANSE FROM MO INTO EASTERN IA/WESTERN IL. MIXED LAYER INSTABILITY WILL BE HIGH OVER THIS AREA INCLUDING THE WESTERN FORECAST AREA GIVEN TEMPS IN THE UPPER 80S TO LOWER 90S. WHILE SOME FORM OF MCS OR MULTIPLE CLUSTERS ARE PROBABLE TO BE MOVING EASTWARD OVER SOUTHERN WI/FAR NORTHERN IL DURING THE AFTERNOON WITH THE SHORT WAVES...DEVELOPMENT IS FAVORED TO WORK ITS WAY SOUTH AND BACK TO THE SOUTHWEST FROM THERE IN THE MOIST UNSTABLE AIR MASS DURING THE MID-AFTERNOON. DEEP LAYER SHEAR IS ANTICIPATED TO BE INCREASING TO AROUND 30-35 KT BY LATE AFTERNOON WITH ORGANIZED STORMS EXPECTED TO BE ALL WORKING THEIR WAY EASTWARD. AS THE PRIMARY UPPER TROUGH APPROACHES THIS EVENING...LARGER SCALE ASCENT AND FORCING IS LIKELY TO CONTINUE REGIONAL DEVELOPMENT OF STORMS NEAR AND AHEAD OF THE SURFACE FRONT. SO WHILE THERE LOOKS TO BE TWO PRIMARY FOCUSES FOR STORMS THIS AFTERNOON INTO TONIGHT...THERE IS NOT REALLY ANTICIPATED TO BE MUCH OF A BREAK AND THE HIGH PWAT AND UNSTABLE AIR SHOULD ALLOW FOR PLENTY OF COVERAGE. THAT COVERAGE MAY INITIALLY BE A LITTLE LIMITED DEPENDING ON DEBRIS CLOUD COVER BUT IS ANTICIPATED TO BE ITS HIGHEST LATER THIS AFTERNOON THROUGH EARLY OVERNIGHT. THE MOST FAVORED MODE FOR STORMS IS MULTICELL AND SEGMENTS CAPABLE OF SCATTERED DAMAGING WINDS...ESPECIALLY AS THE STRONGER MID-LEVEL JET OVERRIDES THE FRONT THIS EVENING INTO EARLY OVERNIGHT. SOME DEVELOPMENT THIS AFTERNOON THROUGH MID-EVE HAS THE POTENTIAL TO BE SUPERCELLULAR. THE LOW-LEVEL SHEAR IS FAIRLY ANEMIC MUCH OF THIS AFTERNOON /AOB 10 KT/ BUT QUICKLY INCREASES LATE INTO EARLY THIS EVE DUE TO THE DEEPENING LOW AND INCREASING LLJ. THIS WILL HELP FAVOR COLD POOL SUSTAINABILITY AND DOES PRESENT AT LEAST SOME TORNADO THREAT...ALTHOUGH IT LOOKS LIKE SURFACE WINDS MAY BE BACKED MORE TO THE WEST OF THE FORECAST AREA IMMEDIATELY AHEAD OF A SUBTLE SECONDARY SURFACE LOW MOVING UP THE FRONT. SO THE PRIMARY THREAT WILL REMAIN WIND AND OF COURSE HEAVY RAIN WITH EXTREMELY EFFICIENT RAIN PRODUCTION WILL OCCUR IN ANY STORMS TODAY AND TONIGHT. EVEN THOUGH FORWARD PROPAGATION OF STORMS SHOULD BE ON THE INCREASE TONIGHT...SO WILL DEEP MOISTURE REPLENISHMENT AND SIMPLY PUT THE ABSOLUTE MOISTURE IS SO HIGH IT WONT TAKE MUCH TO GET HIGH RAINFALL RATES SUCH AS WE SAW YESTERDAY MORNING. THERE WILL LIKELY BE SWATHS OF RAINFALL IN EXCESS OF ONE TO TWO INCHES ACROSS THE IMMEDIATE REGION...BUT WHERE EXACTLY THEY OCCUR IS TOO CHALLENGING TO LOCK DOWN. DEBATED ON A FLASH FLOOD WATCH BUT FEEL THE THREAT IS TOO LOCALIZED AT THIS TIME FOR A WATCH. CONFIDENCE...MEDIUM. WEDNESDAY...ONGOING SCATTERED SHOWERS AND STORMS ARE POSSIBLE ACROSS MAINLY THE SOUTHERN AND EASTERN FORECAST AREA IN THE MORNING WITH STILL AT LEAST SOME HEAVY RAIN THREAT. WARM 850-925MB AIR BEHIND THE SURFACE WIND SHIFT WILL STILL FAVORED HIGHS IN THE MID TO POSSIBLY EVEN UPPER 80S IN THE SOUTH. DRIER AIR WILL GRADUALLY FILTER IN DURING THE LATER AFTERNOON AND NIGHT PER GUIDANCE. CONFIDENCE...HIGH. THURSDAY THROUGH MONDAY...PRIMARILY DRY WEATHER IS EXPECTED OVER THE AREA ALTHOUGH THE TREND IN BOTH THE EC AND GFS THEIR LAST MULTIPLE RUNS SUPPORTS WARMER TEMPERATURES THIS WEEKEND WITH MID AND MAYBE EVEN UPPER 80S SEEN. HAVE COLLABORATED AND LEANED TOWARD THE WARMER MEX GUIDANCE. THE PATTERN STILL APPEARS BLOCKED JUST WITH THE AREA MORE UNDER THE INFLUENCE OF THE UPPER RIDGE TO THE WEST. MTF && .HYDROLOGY... 410 AM CDT THE VERY MOIST AIR MASS WILL SUPPORT EFFICIENT RAINFALL PRODUCTION FROM ANY THUNDERSTORMS TODAY AND TONIGHT. THIS MAY PRESENT FLASH FLOODING ESPECIALLY ON THE LOCAL LEVEL AS OPPOSED TO ANY WIDESPREAD THREAT. THAT AND THE FACT THERE IS NOT A GREAT SET UP FOR TRUE TRAINING STORMS IS WHY NO FLASH FLOOD WATCH AT THIS TIME. HOWEVER...IF ANY STORMS ARE IN A PARTICULARLY VULNERABLE AREA...SUCH AS A METRO OR A QUICK-RESPONDING WATERSHED...IT COULD BE TROUBLE. THESE TYPE OF HIGH RATES WERE ALREADY SEEN YESTERDAY MORNING WITH A NARROW SWATH OF ONE AND A HALF TO ESTIMATED THREE PLUS INCHES OF RAIN SEEN FROM RE-FIRING STORMS IN THE WEST CHICAGO METRO. HIGH RESOLUTION MODEL GUIDANCE INDICATES SUCH SWATHS ARE PROBABLE IN THE REGION THIS AFTERNOON INTO TONIGHT ALTHOUGH WHERE IS STILL UNCERTAIN. THE GENERAL RAINFALL FORECAST IS FOR MOST AREAS TO SEE AROUND AN INCH OR A LITTLE OVER BY WEDNESDAY MORNING. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 12Z... * LINGERING FOG TO QUICKLY DISSIPATE THIS MORNING. * AN INCREASE IN SHOWERS/TS EXPECTED BY MID DAY...AND THEN EXPECTED TO INCREASE IN COVERAGE AND INTENSITY THROUGH THE AFTERNOON. * MORE WIDESPREAD SHOWERS/TS POSSIBLY TO MOVE ACROSS THE TERMINALS ONCE AGAIN LATER THIS EVENING AND OVERNIGHT. * VARIABLE WINDS THIS MORNING BECOMING LIGHT OUT OF THE EAST NORTHEAST BY MID MORNING...AND THEN SLOWLY BECOMING MORE SOUTHEAST THIS AFTERNOON AND EVENTUALLY SOUTHERLY THIS EVENING. RODRIGUEZ //DISCUSSION...UPDATED 12Z... RELATIVELY QUIET ACROSS THE TERMINALS THIS MORNING WHILE SOME FOG/HAZE REMAINS OVERHEAD...BUT WITH THE MORE DENSE FOG REMAINING AWAY FROM THE TERMINALS AT THIS TIME. ANY FOG THIS MORNING SHOULD QUICKLY DISSIPATE OVER THE NEXT HOUR WITH ANY THREAT OF LOWER VIS/CEILINGS COMING SOUTH DOWN THE LAKE REMAINING LOW AT THIS TIME. ALTHOUGH THIS AREA IS STILL SLOWLY MOVING SOUTH DOWN THE LAKE...VEERING WINDS AND SHOULD HELP LIMIT THIS SOUTHWARD MOMENTUM KEEPING THIS FOG NORTH OF THE TERMINALS. THEN SHIFT GEARS TO REDEVELOPMENT OF SHOWERS/TS LATER THIS MORNING...AS PRECIP DEVELOPS OUT AHEAD OF AN APPROACHING MID LEVEL DISTURBANCE. AS THIS DISTURBANCE DRAWS NEAR...EXPECT CURRENT THUNDERSTORMS OVER IOWA AS WELL AS OTHER DEVELOPMENT TO MOVE ACROSS THROUGH NORTHERN ILLINOIS/NORTHWEST INDIANA BY MID DAY WITH SOME UPWARD GROWTH IN COVERAGE AND INTENSITY EXPECTED INTO THE EARLY AFTERNOON. DO EXPECT A BRIEF LULL IN THE ACTIVITY AFTER THIS INITIAL PRECIP MOVES THROUGH...BUT WITH DEVELOPMENT STILL POSSIBLE GOING INTO THE EARLY EVENING. STILL MONITORING THE POTENTIAL FOR A MORE WIDESPREAD AREA OF THUNDERSTORMS TO MOVE ACROSS THE TERMINALS LATER THIS EVENING AND OVERNIGHT. ALTHOUGH IT STILL SEEMS FAVORABLE FOR THIS TO MOVE ACROSS THE TERMINALS...WILL NEED TO MONITOR LATER TRENDS AFTER THIS INITIAL PRECIP THIS AFTERNOON MOVES THROUGH. WINDS REMAIN LIGHT/VARIABLE THIS MORNING BUT ANTICIPATE A TREND TOWARDS AN EAST NORTHEAST WIND OVER THE NEXT SEVERAL HOURS. WINDS ALONG THE LAKE ARE ALREADY THIS EASTERLY COMPONENT AND WITH THE SUN RISING COINCIDING WITH A WEAK GRADIENT...FEEL THAT IT WONT TAKE MUCH FOR THIS NORTHEAST WIND TO DEVELOP OVER ORD/MDW/GYY THIS MORNING. THEN EXPECT A SLOW TREND TOWARDS THE SOUTHEAST AND EVENTUALLY SOUTH THIS AFTERNOON/EVENING...BEFORE WINDS CONTINUE TO VEER TO THE WEST OVERNIGHT. RODRIGUEZ //ORD AND MDW CONFIDENCE...UPDATED 12Z... * HIGH CONFIDENCE WITH FOG/VIS THIS MORNING. * MEDIUM CONFIDENCE WITH SHOWERS/TS MID DAY THROUGH THE AFTERNOON. * MEDIUM CONFIDENCE WITH SHOWERS/TS LATER THIS EVENING/OVERNIGHT. * MEDIUM CONFIDENCE WITH WIND SPEED/DIRECTION. RODRIGUEZ //OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z... WEDNESDAY NIGHT...VFR. THURSDAY...VFR. FRIDAY...VFR. SATURDAY...VFR. SUNDAY...VFR. MONDAY...VFR. RODRIGUEZ && .MARINE... 427 AM CDT MAIN FORECAST CONCERN IN THE NEAR TERM IS FOR AREAS ACROSS THE NORTHERN TWO THIRDS OF THE LAKE...WHERE DENSE FOG HAS SETTLED IN. EXPECT THIS FOG TO PERSIST AT LEAST THROUGH THE AFTERNOON WITH CURRENT THINKING THAT THIS FOG WILL CHURN UP WITH APPROACHING PRECIP. ALTHOUGH CONFIDENCE IS LOW...AND ITS POSSIBLE THE CURRENT DENSE FOG ADVISORY IN PLACE THROUGH THE AFTERNOON COULD NEED TO BE EXTENDED THROUGH THE EVENING. THERE IS ALSO POTENTIAL FOR THE MORE DENSE FOG TO PUSH FURTHER DOWN THE LAKE EARLY THIS MORNING...BEFORE WINDS BEGIN TO SHIFT AND BRING A STOP TO THIS SOUTHWARD MOVING AREA OF FOG. CURRENT LIGHT NORTHERLY WINDS IN PLACE ACROSS THE LAKE WILL TURN MORE SOUTHERLY THROUGHOUT TODAY AS THE NEXT SYSTEM APPROACHES FROM THE WEST. AS THIS SYSTEM THEN PROGRESSES ACROSS THE LAKE TONIGHT...EXPECT SOUTHWEST WINDS TO BECOME MORE WESTERLY WHILE INCREASING MORE TOWARDS THE 10 TO 20 KT RANGE. THEN AS HIGH PRESSURE SLOWLY BUILDS EAST TOWARDS THE LAKE...EXPECT GENERALLY NORTHERLY WINDS THROUGH THE REST OF THE WORK WEEK. RODRIGUEZ && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...DENSE FOG ADVISORY...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565- LMZ567-LMZ669-LMZ671-LMZ673-LMZ868-LMZ870-LMZ872-LMZ874 UNTIL 3 PM TUESDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1057 AM CDT TUE JUL 9 2013 .UPDATE... ISSUED AT 1050 AM CDT TUE JUL 9 2013 2 MAJOR UPDATES HAVE BEEN SEND THIS MORNING...REFLECTING CHANGES BASED ON RADAR TRENDS...AND NOW BOTH CONVECTIVE TRENDS COMBINED WITH MORNING UA ANALYSIS AND EARLY SIGNALS IN MODEL GUIDANCE. THE PARADE OF TWO MCV FEATURES IS NOTED ON RADAR AND SATELLITE...AND THUS THE NEXT 4 HOURS WILL CERTAINLY BE OUR MAIN SHOW WITH RESPECT TO RAINFALL POTENTIAL. AMOUNTS THUS FAR ARE SCATTERED AND SIGNIFICANT ...OVER 1 INCH......BUT MOST OF THE AREA RECEIVING ONLY LIGHT AMOUNTS OR NEARLY DRY...ESPECIALLY SOUTH. SURFACE CAPE WILL BE LIMITED TO ONLY THE SOUTH TODAY AND EARLY THIS EVENING...THUS OUR BEST POTENTIAL FOR MORE SIGNIFICANT STORMS IS THERE. ELSEWHERE I HAVE CONTINUED TO LOWER EVENING POPS...AS WELL AS AFTERNOON POPS IN THE WEST. TONIGHT COULD VERY WELL BE DRY OVER OUR WESTERN 1/3 OF THE CWA...AND POSSIBLY WESTERN 2/3 IF THE VEERED MOISTURE PLUME CANNOT RECOVER FROM THE MCV PASSAGES. THIS GREATLY WILL LOWER THE SEVERE THREAT...AND I WILL AWAIT THE SPC UPDATE BEFORE UPDATING THE HWO TO REFLECT THAT POSSIBLE LOWERED MAGNITUDE OF THE THREAT. TEMPERATURES HAVE BEEN LOWERED TO MAINLY MID 80S HIGHS...WHICH SHOULD EASILY OCCUR ONCE CONVECTION STOPS FIRING...BUT SAFE TO SAY...OUR NEAR ADVISORY LEVEL HEAT WILL NOT VERIFY TODAY. IT WILL MOST CERTAINLY BE QUITE MUGGY OUT THERE. ERVIN && .SYNOPSIS... ISSUED AT 330 AM CDT TUE JUL 9 2013 06Z MSAS SFC ANALYSIS SUPPORTIVE OF WEAK LOW OVER CENTRAL SD WITH STATIONARY FRONT EXTENDING SEWD FROM THE LOW AND BISECTING EASTERN IA AND NORTHWEST IL. MOISTURE IS POOLING ALONG THE FRONT WITH DEWPTS OF 70-75F. 00Z KDVN RAOB SHOWS DEEP MOISTURE WITH PRECIPITABLE WATER VALUES OF NEARLY 2 INCHES... WHICH IS AROUND 160 PERCENT OF NORMAL AND NEARLY 2 STANDARD DEVIATIONS ABOVE THE MEAN. CONVECTIVELY ENHANCED VORT MAX IS TRACKING THROUGH EASTERN NE ATTM WITH RADARS SHOWING SHOWERS AND STORMS AHEAD OF THIS FEATURE INTO WESTERN IA. ADDITIONAL COMPLEX OF STORMS WAS OVER THE DAKOTAS AHEAD OF COLD FRONT AND SHORTWAVE MOVING EAST THROUGH FAR SOUTHERN ALBERTA PROVINCE AND NORTHERN MT. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 330 AM CDT TUE JUL 9 2013 SUGGESTIONS OF 2 MAIN ROUNDS OF STORMS THROUGH THE PERIOD. AS CONVECTIVELY ENHANCED VORT MAX MOVES EAST FROM NE ANTICIPATE SHOWERS AND STORMS TRACKING AHEAD OF THIS FEATURE TO MOVE ACROSS THE REGION BY MID AM THROUGH EARLY AFTN. PRIOR TO THE ARRIVAL OF THESE STORMS COULD SEE ADDITIONAL DEVELOPMENT PRIOR TO MID AM OVER THE AREA WITH WARM ADVECTION WING. POTENTIAL FOR SOME STRENGTHENING OF MID LEVEL WINDS AND INTENSIFICATION OF STORMS BY LATE AM AND AFTN FOR RISK OF FEW STRONG TO ISOLD SEVERE STORMS WITH MOST RECENT RUNS OF HRRR 2-5KM UPDRAFT HELICITY AND 3 KM VELOCITY CONTINUING TO SUGGEST THIS RISK NEAR AND ESPECIALLY NORTH OF I-80. MAY SEE BREAK IN ACTION OR RELATIVE LULL IN ACTIVITY BY MID-LATE AFTN WITH FOCUS SHIFTING BACK NORTHWEST FOR DEVELOPMENT AHEAD OF COLD FRONT. LIKELY TO SEE ANOTHER ROUND OF STORMS MOVE THROUGH THIS EVENING INTO OVERNIGHT AHEAD OF COLD FRONT. STRENGTHENING 40-60 KT MID LEVEL SPEED MAX SPREADING BEHIND FRONT COUPLED WITH VERY UNSTABLE ENVIRONMENT WILL SUPPORT RISK OF SEVERE STORMS WITH POTENTIAL FOR UPSCALE GROWTH TO LINEAR MCS WITH MAINLY DAMAGING WIND THREAT. HEAVY RAIN WILL BE A CONCERN AS WELL GIVEN THE DEEP ALMOST TROPICAL MOISTURE IN PLACE. STORMS SHOULD BE MOVING ALONG MORE THAN WE/VE SEEN OF LATE BUT WILL BE VERY EFFICIENT RAIN PRODUCERS WITH RATES LIKELY 1-2"/HR. THUS... CANT RULE OUT SOME LOCALIZED FLASH FLOODING AND WILL HAVE TO BE ESPECIALLY WATCHFULL OVER PORTIONS OF DELAWARE AND DUBUQUE COUNTIES WHICH HAVE SEEN 2-5 INCHES PAST 24-36 HRS. EXPECT PCPN SHOULD BE DIMINISHING FROM NW TO SE OVRNGT WITH PASSAGE OF COLD FRONT. HIGHS TDY TRICKY WITH CLOUDS AND PCPN BUT OVERALL SHOULD RANGE FROM MID 80S TO THE LOWER 90S. SOME MIXING OUT OF DEWPTS MAY OCCUR BUT AT LEAST UPPER 60S TO LOWER 70S EXPECTED ON DEWPTS... WHICH COMBINED WITH TEMPS WILL MAKE FOR HEAT INDICES MAINLY IN THE MID TO UPPER 90S. COOLER AND DRIER AIR LAGS BEHIND FRONT TNGT... THUS LOWS ONLY DROP INTO THE UPPER 60S TO LOWER 70S. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 330 AM CDT TUE JUL 9 2013 WEDNESDAY AND THURSDAY...AS L/W TROF CONTINUES TO DEEPEN AND ESTABLISH ACRS THE GRT LKS...SEASONABLY STRONG LLVL HIGH PRESSURE WILL LOOK TO DUMP DOWN THE NORTHERN PLAINS AND MO RVR VALLEY ON WED. A FEW POST-FRONTAL SHOWERS AND STORMS MAY BE OCCURRING ACRS THE FAR EASTERN/SOUTHERN CWA WED MORNING BUT BULK OF THE ACTIVITY SHOULD BE GONE BY 15Z. VEERING AND INCREASING BOUNDARY LAYER FLOW AS WELL AS INCOMING SUBSIDENCE SHOULD CLEAR THINGS OUT ON WED...BUT SOME LAG IN CAA TO ALLOW TEMPS TO WARM INTO THE LOW TO MID 80S EVEN POST- FRONTALLY. A RATHER BREEZY NORTHWEST TO NORTH WIND OF 15-20 MPH. CLEAR SKIES AND WIND DROP OFF WED NIGHT TO ALLOW SOME AREA TEMPS TO DROP OFF INTO THE 50S. LLVL HIGH PRESSURE CONTINUING TO MIGRATE EASTWARD ACRS THE REGION TO MAKE FOR A CHAMBER OF COMMERCE DAY THU WITH HIGHS IN THE UPPER 70S TO LOWER 80S...SUNSHINE AND LOWER HUMIDITY. THU NIGHT SEASONABLY COOL AGAIN WITH LOWS IN THE 50S AND LOW 60S. FRIDAY THROUGH NEXT MONDAY...TRENDS OF THE LATEST RUN 00Z MEDIUM RANGE SOLUTIONS AND ENSEMBLES SUGGEST SOME DIGGING TROFFINESS IN THE PACIFIC NORTHWEST/WESTERN CANADA TO TRANSLATE INTO PUMPED UP UPPER RIDGING ACRS THE MID CONUS FRI INTO SAT. THUS WHILE THERMAL DOME INTENSIFIES ACRS THE GRT BSN INTO THE SOUTHWESTERN PLAINS...MCS TRACK/RING OF FIRE PATTERN TO ESTABLISH IN NORMAL DEEP SUMMER LOCATION OF NORTHWESTERN HIGH PLAINS...UPPER MS RVR VALLEY...SOUTHERN CANADA AND INTO THE GRT LKS. LATEST INDICATIONS SUGGEST A LESSENING CHANCE FOR SOME OF THIS MCS ACTIVITY TO SPILL DOWN ACRS THE NORTHERN CWA EITHER FRI NIGHT OR SAT NIGHT WHILE TEMPERATURES START TO REBOUND BACK TO NORMAL OR EVEN WARMER. BY SUNDAY...WESTERLIES FIRMLY ESTABLISH ACRS THE U.S.-CANADIAN BORDER REGION WITH UPPER RIDGING DOMINATING ACRS THE SOUTHERN 2/3S OF THE CONUS. LONGER RANGE THERMAL PROFILES SUGGEST ENOUGH AIRMASS MODIFICATION TO DRIVE SUNDAY HIGHS UP INTO AT LEAST THE LOWER 90S ALONG WITH INCREASING SFC DPTS/HUMIDITY. PASSING WAVE IN THIS PROGRESSIVE FLOW MAY TRY TO SHUNT DOWN A WEAKENING SFC BOUNDARY DOWN TOWARD OR ACRS THE CWA LATER SUNDAY NIGHT OR MONDAY AND GET SLOWED AS IT ALIGNS PARALLEL TO MEAN STEERING FLOW. THUS THIS WINDOW MAY BE THE NEXT REAL CHANCE FOR SOME PRECIP IN THE AREA AFTER TODAY/TONIGHT. LONGER RANGE SIGNALS ON THE LATEST RUNS ESPECIALLY THE NEW 00Z ECMWF SUGGESTS THAT THIS BROAD UPPER RIDGING PATTERN TO CONTINUE TO REIGN ACRS MUCH OF THE CONUS WELL INTO MID NEXT WEEK...WHILE THE TROPICS CONTINUE TO GET INTERESTING. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING) ISSUED AT 643 AM CDT TUE JUL 9 2013 SHOWERS AND STORMS WILL MOVE ACROSS THE AREA THROUGH EARLY AFTN AFFECTING KCID...KDBQ AND KMLI TERMINALS. MVFR TO LOCAL IFR CONDITIONS MAINLY FOR VSBYS 1-5SM WITH PCPN. HAVE VCSH WORDING FURTHER SOUTH AT KBRL WITH LESS CERTAINTY ON COVERAGE AND IMPACT TO TERMINAL. ANOTHER ROUND OF SHOWERS AND STORMS IS LIKELY LATE THIS AFTERNOON AND TONIGHT AHEAD OF A COLD FRONT. STRONG TO SEVERE WINDS COULD ACCOMPANY SOME OF THE STORMS. ADDITIONAL SHOWERS COULD LINGER OVERNIGHT IN WAKE OF FRONTAL PASSAGE. LOW RISK OF MVFR CIGS LATE TONIGHT WITH PROBABILITY APPEARING TOO LOW ATTM FOR INCLUSION IN TAFS. OUTSIDE OF ANY STORMS... WINDS TODAY TO BECOME SSW AROUND 10 KTS AND MAY BE GUSTY AT TIMES. WINDS TO SHIFT TO NORTHWEST WITH FRONTAL PASSAGE LATE TNGT. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ UPDATE...ERVIN SYNOPSIS...05 SHORT TERM...05 LONG TERM...12 AVIATION...05
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
750 AM CDT TUE JUL 9 2013 .UPDATE... ISSUED AT 743 AM CDT TUE JUL 9 2013 SHOWERS AND STORMS ON MORE SCATTERED BASIS HAVE FILLED BACK IN TO WESTERN IA. BASED ON THIS TREND CONCERN IS MOUNTING THAT WE MAY JUST SEE OCCASIONAL SHOWERS AND STORMS ALL DAY. SHOULD THIS OCCUR IT WOULD AID IN KEEPING HIGH TEMPS COOLER THAN FCST... AND ALSO WOULD HAVE MAKE COVERAGE OF STORMS ALONG FRONT AND SEVERE THREAT LATE AFTN/EVE MUCH MORE UNCERTAIN. NO MAJOR CHGS MADE WITH 7 AM UPDATE BUT WILL PASS ON CONCERNS TO NEXT SHIFT. && .SYNOPSIS... ISSUED AT 330 AM CDT TUE JUL 9 2013 06Z MSAS SFC ANALYSIS SUPPORTIVE OF WEAK LOW OVER CENTRAL SD WITH STATIONARY FRONT EXTENDING SEWD FROM THE LOW AND BISECTING EASTERN IA AND NORTHWEST IL. MOISTURE IS POOLING ALONG THE FRONT WITH DEWPTS OF 70-75F. 00Z KDVN RAOB SHOWS DEEP MOISTURE WITH PRECIPITABLE WATER VALUES OF NEARLY 2 INCHES... WHICH IS AROUND 160 PERCENT OF NORMAL AND NEARLY 2 STANDARD DEVIATIONS ABOVE THE MEAN. CONVECTIVELY ENHANCED VORT MAX IS TRACKING THROUGH EASTERN NE ATTM WITH RADARS SHOWING SHOWERS AND STORMS AHEAD OF THIS FEATURE INTO WESTERN IA. ADDITIONAL COMPLEX OF STORMS WAS OVER THE DAKOTAS AHEAD OF COLD FRONT AND SHORTWAVE MOVING EAST THROUGH FAR SOUTHERN ALBERTA PROVINCE AND NORTHERN MT. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 330 AM CDT TUE JUL 9 2013 SUGGESTIONS OF 2 MAIN ROUNDS OF STORMS THROUGH THE PERIOD. AS CONVECTIVELY ENHANCED VORT MAX MOVES EAST FROM NE ANTICIPATE SHOWERS AND STORMS TRACKING AHEAD OF THIS FEATURE TO MOVE ACROSS THE REGION BY MID AM THROUGH EARLY AFTN. PRIOR TO THE ARRIVAL OF THESE STORMS COULD SEE ADDITIONAL DEVELOPMENT PRIOR TO MID AM OVER THE AREA WITH WARM ADVECTION WING. POTENTIAL FOR SOME STRENGTHENING OF MID LEVEL WINDS AND INTENSIFICATION OF STORMS BY LATE AM AND AFTN FOR RISK OF FEW STRONG TO ISOLD SEVERE STORMS WITH MOST RECENT RUNS OF HRRR 2-5KM UPDRAFT HELICITY AND 3 KM VELOCITY CONTINUING TO SUGGEST THIS RISK NEAR AND ESPECIALLY NORTH OF I-80. MAY SEE BREAK IN ACTION OR RELATIVE LULL IN ACTIVITY BY MID-LATE AFTN WITH FOCUS SHIFTING BACK NORTHWEST FOR DEVELOPMENT AHEAD OF COLD FRONT. LIKELY TO SEE ANOTHER ROUND OF STORMS MOVE THROUGH THIS EVENING INTO OVERNIGHT AHEAD OF COLD FRONT. STRENGTHENING 40-60 KT MID LEVEL SPEED MAX SPREADING BEHIND FRONT COUPLED WITH VERY UNSTABLE ENVIRONMENT WILL SUPPORT RISK OF SEVERE STORMS WITH POTENTIAL FOR UPSCALE GROWTH TO LINEAR MCS WITH MAINLY DAMAGING WIND THREAT. HEAVY RAIN WILL BE A CONCERN AS WELL GIVEN THE DEEP ALMOST TROPICAL MOISTURE IN PLACE. STORMS SHOULD BE MOVING ALONG MORE THAN WE/VE SEEN OF LATE BUT WILL BE VERY EFFICIENT RAIN PRODUCERS WITH RATES LIKELY 1-2"/HR. THUS... CANT RULE OUT SOME LOCALIZED FLASH FLOODING AND WILL HAVE TO BE ESPECIALLY WATCHFULL OVER PORTIONS OF DELAWARE AND DUBUQUE COUNTIES WHICH HAVE SEEN 2-5 INCHES PAST 24-36 HRS. EXPECT PCPN SHOULD BE DIMINISHING FROM NW TO SE OVRNGT WITH PASSAGE OF COLD FRONT. HIGHS TDY TRICKY WITH CLOUDS AND PCPN BUT OVERALL SHOULD RANGE FROM MID 80S TO THE LOWER 90S. SOME MIXING OUT OF DEWPTS MAY OCCUR BUT AT LEAST UPPER 60S TO LOWER 70S EXPECTED ON DEWPTS... WHICH COMBINED WITH TEMPS WILL MAKE FOR HEAT INDICES MAINLY IN THE MID TO UPPER 90S. COOLER AND DRIER AIR LAGS BEHIND FRONT TNGT... THUS LOWS ONLY DROP INTO THE UPPER 60S TO LOWER 70S. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 330 AM CDT TUE JUL 9 2013 WEDNESDAY AND THURSDAY...AS L/W TROF CONTINUES TO DEEPEN AND ESTABLISH ACRS THE GRT LKS...SEASONABLY STRONG LLVL HIGH PRESSURE WILL LOOK TO DUMP DOWN THE NORTHERN PLAINS AND MO RVR VALLEY ON WED. A FEW POST-FRONTAL SHOWERS AND STORMS MAY BE OCCURRING ACRS THE FAR EASTERN/SOUTHERN CWA WED MORNING BUT BULK OF THE ACTIVITY SHOULD BE GONE BY 15Z. VEERING AND INCREASING BOUNDARY LAYER FLOW AS WELL AS INCOMING SUBSIDENCE SHOULD CLEAR THINGS OUT ON WED...BUT SOME LAG IN CAA TO ALLOW TEMPS TO WARM INTO THE LOW TO MID 80S EVEN POST- FRONTALLY. A RATHER BREEZY NORTHWEST TO NORTH WIND OF 15-20 MPH. CLEAR SKIES AND WIND DROP OFF WED NIGHT TO ALLOW SOME AREA TEMPS TO DROP OFF INTO THE 50S. LLVL HIGH PRESSURE CONTINUING TO MIGRATE EASTWARD ACRS THE REGION TO MAKE FOR A CHAMBER OF COMMERCE DAY THU WITH HIGHS IN THE UPPER 70S TO LOWER 80S...SUNSHINE AND LOWER HUMIDITY. THU NIGHT SEASONABLY COOL AGAIN WITH LOWS IN THE 50S AND LOW 60S. FRIDAY THROUGH NEXT MONDAY...TRENDS OF THE LATEST RUN 00Z MEDIUM RANGE SOLUTIONS AND ENSEMBLES SUGGEST SOME DIGGING TROFFINESS IN THE PACIFIC NORTHWEST/WESTERN CANADA TO TRANSLATE INTO PUMPED UP UPPER RIDGING ACRS THE MID CONUS FRI INTO SAT. THUS WHILE THERMAL DOME INTENSIFIES ACRS THE GRT BSN INTO THE SOUTHWESTERN PLAINS...MCS TRACK/RING OF FIRE PATTERN TO ESTABLISH IN NORMAL DEEP SUMMER LOCATION OF NORTHWESTERN HIGH PLAINS...UPPER MS RVR VALLEY...SOUTHERN CANADA AND INTO THE GRT LKS. LATEST INDICATIONS SUGGEST A LESSENING CHANCE FOR SOME OF THIS MCS ACTIVITY TO SPILL DOWN ACRS THE NORTHERN CWA EITHER FRI NIGHT OR SAT NIGHT WHILE TEMPERATURES START TO REBOUND BACK TO NORMAL OR EVEN WARMER. BY SUNDAY...WESTERLIES FIRMLY ESTABLISH ACRS THE U.S.-CANADIAN BORDER REGION WITH UPPER RIDGING DOMINATING ACRS THE SOUTHERN 2/3S OF THE CONUS. LONGER RANGE THERMAL PROFILES SUGGEST ENOUGH AIRMASS MODIFICATION TO DRIVE SUNDAY HIGHS UP INTO AT LEAST THE LOWER 90S ALONG WITH INCREASING SFC DPTS/HUMIDITY. PASSING WAVE IN THIS PROGRESSIVE FLOW MAY TRY TO SHUNT DOWN A WEAKENING SFC BOUNDARY DOWN TOWARD OR ACRS THE CWA LATER SUNDAY NIGHT OR MONDAY AND GET SLOWED AS IT ALIGNS PARALLEL TO MEAN STEERING FLOW. THUS THIS WINDOW MAY BE THE NEXT REAL CHANCE FOR SOME PRECIP IN THE AREA AFTER TODAY/TONIGHT. LONGER RANGE SIGNALS ON THE LATEST RUNS ESPECIALLY THE NEW 00Z ECMWF SUGGESTS THAT THIS BROAD UPPER RIDGING PATTERN TO CONTINUE TO REIGN ACRS MUCH OF THE CONUS WELL INTO MID NEXT WEEK...WHILE THE TROPICS CONTINUE TO GET INTERESTING. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING) ISSUED AT 643 AM CDT TUE JUL 9 2013 SHOWERS AND STORMS WILL MOVE ACROSS THE AREA THROUGH EARLY AFTN AFFECTING KCID...KDBQ AND KMLI TERMINALS. MVFR TO LOCAL IFR CONDITIONS MAINLY FOR VSBYS 1-5SM WITH PCPN. HAVE VCSH WORDING FURTHER SOUTH AT KBRL WITH LESS CERTAINTY ON COVERAGE AND IMPACT TO TERMINAL. ANOTHER ROUND OF SHOWERS AND STORMS IS LIKELY LATE THIS AFTERNOON AND TONIGHT AHEAD OF A COLD FRONT. STRONG TO SEVERE WINDS COULD ACCOMPANY SOME OF THE STORMS. ADDITIONAL SHOWERS COULD LINGER OVERNIGHT IN WAKE OF FRONTAL PASSAGE. LOW RISK OF MVFR CIGS LATE TONIGHT WITH PROBABILITY APPEARING TOO LOW ATTM FOR INCLUSION IN TAFS. OUTSIDE OF ANY STORMS... WINDS TODAY TO BECOME SSW AROUND 10 KTS AND MAY BE GUSTY AT TIMES. WINDS TO SHIFT TO NORTHWEST WITH FRONTAL PASSAGE LATE TNGT. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ UPDATE...05 SYNOPSIS...05 SHORT TERM...05 LONG TERM...12 AVIATION...05
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
658 AM CDT TUE JUL 9 2013 .SYNOPSIS... ISSUED AT 330 AM CDT TUE JUL 9 2013 06Z MSAS SFC ANALYSIS SUPPORTIVE OF WEAK LOW OVER CENTRAL SD WITH STATIONARY FRONT EXTENDING SEWD FROM THE LOW AND BISECTING EASTERN IA AND NORTHWEST IL. MOISTURE IS POOLING ALONG THE FRONT WITH DEWPTS OF 70-75F. 00Z KDVN RAOB SHOWS DEEP MOISTURE WITH PRECIPITABLE WATER VALUES OF NEARLY 2 INCHES... WHICH IS AROUND 160 PERCENT OF NORMAL AND NEARLY 2 STANDARD DEVIATIONS ABOVE THE MEAN. CONVECTIVELY ENHANCED VORT MAX IS TRACKING THROUGH EASTERN NE ATTM WITH RADARS SHOWING SHOWERS AND STORMS AHEAD OF THIS FEATURE INTO WESTERN IA. ADDITIONAL COMPLEX OF STORMS WAS OVER THE DAKOTAS AHEAD OF COLD FRONT AND SHORTWAVE MOVING EAST THROUGH FAR SOUTHERN ALBERTA PROVINCE AND NORTHERN MT. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 330 AM CDT TUE JUL 9 2013 SUGGESTIONS OF 2 MAIN ROUNDS OF STORMS THROUGH THE PERIOD. AS CONVECTIVELY ENHANCED VORT MAX MOVES EAST FROM NE ANTICIPATE SHOWERS AND STORMS TRACKING AHEAD OF THIS FEATURE TO MOVE ACROSS THE REGION BY MID AM THROUGH EARLY AFTN. PRIOR TO THE ARRIVAL OF THESE STORMS COULD SEE ADDITIONAL DEVELOPMENT PRIOR TO MID AM OVER THE AREA WITH WARM ADVECTION WING. POTENTIAL FOR SOME STRENGTHENING OF MID LEVEL WINDS AND INTENSIFICATION OF STORMS BY LATE AM AND AFTN FOR RISK OF FEW STRONG TO ISOLD SEVERE STORMS WITH MOST RECENT RUNS OF HRRR 2-5KM UPDRAFT HELICITY AND 3 KM VELOCITY CONTINUING TO SUGGEST THIS RISK NEAR AND ESPECIALLY NORTH OF I-80. MAY SEE BREAK IN ACTION OR RELATIVE LULL IN ACTIVITY BY MID-LATE AFTN WITH FOCUS SHIFTING BACK NORTHWEST FOR DEVELOPMENT AHEAD OF COLD FRONT. LIKELY TO SEE ANOTHER ROUND OF STORMS MOVE THROUGH THIS EVENING INTO OVERNIGHT AHEAD OF COLD FRONT. STRENGTHENING 40-60 KT MID LEVEL SPEED MAX SPREADING BEHIND FRONT COUPLED WITH VERY UNSTABLE ENVIRONMENT WILL SUPPORT RISK OF SEVERE STORMS WITH POTENTIAL FOR UPSCALE GROWTH TO LINEAR MCS WITH MAINLY DAMAGING WIND THREAT. HEAVY RAIN WILL BE A CONCERN AS WELL GIVEN THE DEEP ALMOST TROPICAL MOISTURE IN PLACE. STORMS SHOULD BE MOVING ALONG MORE THAN WE/VE SEEN OF LATE BUT WILL BE VERY EFFICIENT RAIN PRODUCERS WITH RATES LIKELY 1-2"/HR. THUS... CANT RULE OUT SOME LOCALIZED FLASH FLOODING AND WILL HAVE TO BE ESPECIALLY WATCHFULL OVER PORTIONS OF DELAWARE AND DUBUQUE COUNTIES WHICH HAVE SEEN 2-5 INCHES PAST 24-36 HRS. EXPECT PCPN SHOULD BE DIMINISHING FROM NW TO SE OVRNGT WITH PASSAGE OF COLD FRONT. HIGHS TDY TRICKY WITH CLOUDS AND PCPN BUT OVERALL SHOULD RANGE FROM MID 80S TO THE LOWER 90S. SOME MIXING OUT OF DEWPTS MAY OCCUR BUT AT LEAST UPPER 60S TO LOWER 70S EXPECTED ON DEWPTS... WHICH COMBINED WITH TEMPS WILL MAKE FOR HEAT INDICES MAINLY IN THE MID TO UPPER 90S. COOLER AND DRIER AIR LAGS BEHIND FRONT TNGT... THUS LOWS ONLY DROP INTO THE UPPER 60S TO LOWER 70S. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 330 AM CDT TUE JUL 9 2013 WEDNESDAY AND THURSDAY...AS L/W TROF CONTINUES TO DEEPEN AND ESTABLISH ACRS THE GRT LKS...SEASONABLY STRONG LLVL HIGH PRESSURE WILL LOOK TO DUMP DOWN THE NORTHERN PLAINS AND MO RVR VALLEY ON WED. A FEW POST-FRONTAL SHOWERS AND STORMS MAY BE OCCURRING ACRS THE FAR EASTERN/SOUTHERN CWA WED MORNING BUT BULK OF THE ACTIVITY SHOULD BE GONE BY 15Z. VEERING AND INCREASING BOUNDARY LAYER FLOW AS WELL AS INCOMING SUBSIDENCE SHOULD CLEAR THINGS OUT ON WED...BUT SOME LAG IN CAA TO ALLOW TEMPS TO WARM INTO THE LOW TO MID 80S EVEN POST- FRONTALLY. A RATHER BREEZY NORTHWEST TO NORTH WIND OF 15-20 MPH. CLEAR SKIES AND WIND DROP OFF WED NIGHT TO ALLOW SOME AREA TEMPS TO DROP OFF INTO THE 50S. LLVL HIGH PRESSURE CONTINUING TO MIGRATE EASTWARD ACRS THE REGION TO MAKE FOR A CHAMBER OF COMMERCE DAY THU WITH HIGHS IN THE UPPER 70S TO LOWER 80S...SUNSHINE AND LOWER HUMIDITY. THU NIGHT SEASONABLY COOL AGAIN WITH LOWS IN THE 50S AND LOW 60S. FRIDAY THROUGH NEXT MONDAY...TRENDS OF THE LATEST RUN 00Z MEDIUM RANGE SOLUTIONS AND ENSEMBLES SUGGEST SOME DIGGING TROFFINESS IN THE PACIFIC NORTHWEST/WESTERN CANADA TO TRANSLATE INTO PUMPED UP UPPER RIDGING ACRS THE MID CONUS FRI INTO SAT. THUS WHILE THERMAL DOME INTENSIFIES ACRS THE GRT BSN INTO THE SOUTHWESTERN PLAINS...MCS TRACK/RING OF FIRE PATTERN TO ESTABLISH IN NORMAL DEEP SUMMER LOCATION OF NORTHWESTERN HIGH PLAINS...UPPER MS RVR VALLEY...SOUTHERN CANADA AND INTO THE GRT LKS. LATEST INDICATIONS SUGGEST A LESSENING CHANCE FOR SOME OF THIS MCS ACTIVITY TO SPILL DOWN ACRS THE NORTHERN CWA EITHER FRI NIGHT OR SAT NIGHT WHILE TEMPERATURES START TO REBOUND BACK TO NORMAL OR EVEN WARMER. BY SUNDAY...WESTERLIES FIRMLY ESTABLISH ACRS THE U.S.-CANADIAN BORDER REGION WITH UPPER RIDGING DOMINATING ACRS THE SOUTHERN 2/3S OF THE CONUS. LONGER RANGE THERMAL PROFILES SUGGEST ENOUGH AIRMASS MODIFICATION TO DRIVE SUNDAY HIGHS UP INTO AT LEAST THE LOWER 90S ALONG WITH INCREASING SFC DPTS/HUMIDITY. PASSING WAVE IN THIS PROGRESSIVE FLOW MAY TRY TO SHUNT DOWN A WEAKENING SFC BOUNDARY DOWN TOWARD OR ACRS THE CWA LATER SUNDAY NIGHT OR MONDAY AND GET SLOWED AS IT ALIGNS PARALLEL TO MEAN STEERING FLOW. THUS THIS WINDOW MAY BE THE NEXT REAL CHANCE FOR SOME PRECIP IN THE AREA AFTER TODAY/TONIGHT. LONGER RANGE SIGNALS ON THE LATEST RUNS ESPECIALLY THE NEW 00Z ECMWF SUGGESTS THAT THIS BROAD UPPER RIDGING PATTERN TO CONTINUE TO REIGN ACRS MUCH OF THE CONUS WELL INTO MID NEXT WEEK...WHILE THE TROPICS CONTINUE TO GET INTERESTING. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING) ISSUED AT 643 AM CDT TUE JUL 9 2013 SHOWERS AND STORMS WILL MOVE ACROSS THE AREA THROUGH EARLY AFTN AFFECTING KCID...KDBQ AND KMLI TERMINALS. MVFR TO LOCAL IFR CONDITIONS MAINLY FOR VSBYS 1-5SM WITH PCPN. HAVE VCSH WORDING FURTHER SOUTH AT KBRL WITH LESS CERTAINTY ON COVERAGE AND IMPACT TO TERMINAL. ANOTHER ROUND OF SHOWERS AND STORMS IS LIKELY LATE THIS AFTERNOON AND TONIGHT AHEAD OF A COLD FRONT. STRONG TO SEVERE WINDS COULD ACCOMPANY SOME OF THE STORMS. ADDITIONAL SHOWERS COULD LINGER OVERNIGHT IN WAKE OF FRONTAL PASSAGE. LOW RISK OF MVFR CIGS LATE TONIGHT WITH PROBABILITY APPEARING TOO LOW ATTM FOR INCLUSION IN TAFS. OUTSIDE OF ANY STORMS... WINDS TODAY TO BECOME SSW AROUND 10 KTS AND MAY BE GUSTY AT TIMES. WINDS TO SHIFT TO NORTHWEST WITH FRONTAL PASSAGE LATE TNGT. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ SYNOPSIS...05 SHORT TERM...05 LONG TERM...12 AVIATION...05
AREA FORECAST DISCUSSION
NWS GAYLORD MI
953 AM EDT TUE JUL 9 2013 .SYNOPSIS... ISSUED AT 344 AM EDT TUE JUL 9 2013 THERE WILL BE SMALL CHANCES FOR POP UP SHOWERS AND THUNDERSTORMS TODAY. BETTER CHANCES OF RAINFALL WILL OCCUR TONIGHT INTO WEDNESDAY MORNING AS A COLD FRONT APPROACHES THE REGION. HIGH PRESSURE WILL BEGIN TO BUILD IN BY LATE WEDNESDAY...BRINGING COOLER AND LESS HUMID CONDITIONS FOR MIDWEEK. A WARMING TREND WILL THEN FOLLOW FOR LATE IN THE WEEK INTO THE UPCOMING WEEKEND. && .UPDATE... ISSUED AT 953 AM EDT TUE JUL 9 2013 INTERESTING AND CHALLENGING FORECAST THROUGH LATE AFTERNOON AND EVENING (SOUNDS LIKE THE TYPICAL NORTHERN MICHIGAN TAGLINE DOESN`T IT?)...WITH FORECAST ISSUES CENTERED MAINLY ON CLOUD/FOG/TEMP TRENDS THROUGH MUCH OF THE DAY...BUT SHIFTING TOWARD CONVECTIVE CHANCES BY LATE AFTERNOON AND EVENING. FIRST OF ALL...WILL JUST COME RIGHT OUT AND SAY THAT THIS REMAINS A FAIRLY LOW CONFIDENCE FORECAST WITH REGARD TO ANY CONVECTIVE EVOLUTION LATER TODAY...WITH EVEN LOWER CONFIDENCE ABOUT ANY SEVERE POTENTIAL. HOWEVER...STARTING TO GET THE FEELING CONVECTION MAY TRY TO SNEAK INTO THE PICTURE A LITTLE EARLIER THAN CURRENTLY EXPECTED. MORE ON THAT BELOW...BUT FIRST THINGS FIRST...WE WILL CONTINUE TO DEAL WITH WIDESPREAD STRATUS AND GRADUALLY LIFTING FOG THROUGH AT LEAST LATE MORNING...AND PROBABLY A LITTLE BEYOND. 12Z APX RAOB TELLS THE STORY...WITH A GOOD DEAL OF MOISTURE SANDWICHED BELOW 900MB...AND IN PARTICULAR BELOW 950MB...COURTESY OF A SHALLOW INVERSION AND PLENTIFUL BOUNDARY LAYER MOISTURE FROM YESTERDAY`S MUCH-NEEDED RAINFALL. BASED ON PAST EXPERIENCE...THIS GRUNGE WILL TAKE SOME TIME TO MIX OUT...AND WILL PROBABLY TRANSITION FROM PURE STRATUS TO A THICKER STRATOCU DECK AROUND MIDDAY (WON`T TAKE MUCH TO CONVECTIVELY SATURATE THE 900MB LEVEL PER SOUNDING)...BEFORE ERODING TO SOME DEGREE AS DRIER AIR ABOVE 875 ATTEMPTS TO MIX IN. HOWEVER...SATELLITE ANALYSIS ALREADY SHOWING PLENTY OF THICKER DEBRIS CLOUDS MAKING INROADS THROUGH THE WESTERN LAKES...SO HAVE TO BELIEVE THINGS WILL CLOUD BACK UP FAIRLY QUICKLY ACROSS THE WESTERN CWA THROUGH MID AND LATE AFTERNOON. THIS MAKES TEMPS TRICKY...AND IN GENERAL GUT FEELING SAYS TO LOWER AT LEAST A COUPLE OF DEGREES...THOUGH WITH THE CAVEAT THAT IT DOESN`T TAKE MUCH SUN TO SEND READINGS SOARING THIS TIME OF YEAR. AS FOR PRECIP CHANCES...NOTHING DOING THROUGH AT LEAST 19-21Z...AS STOUT CAPPING AROUND 750MB AND STUBBORNLY SLOW WARMING (AT LEAST INITIALLY) WORK IN TANDEM...COUPLED WITH SUBTLE SHORTWAVE RIDGING ALOFT/NO FORCING. HOWEVER...REALLY WATCHING UPSTREAM CONVECTIVE ACTIVITY...TIED TO A LEADING SHORTWAVE TRAVERSING WESTERN MINNESOTA...OUT AHEAD OF THE MAIN UPPER TROUGH AMPLIFYING INTO THE NORTHERN PLAINS. PER RADAR TRENDS AND SHORT TERM GUIDANCE HINTS...REALLY STARTING TO GET THE FEELING THAT SOME OF THIS ACTIVITY SLIDING EAST FROM NORTHERN IOWA MAY TRY TO IMPACT PARTS OF THE SOUTHERN CWA BY LATE AFTERNOON OR EARLY EVENING. ACTIVITY IS CURRENTLY TRYING TO OUTRUN THE BETTER INSTABILITY...HOWEVER... THIS WON`T BE THE CASE FOR LONG AS STRENGTHENING SOUTHERN FLOW AHEAD OF THE WAVE IS PROGGED TO HELP LIFT A SUBTLE WARM FRONT BACK NORTH INTO CENTRAL WISCONSIN AND EVENTUALLY PARTS OF NORTHERN MICHIGAN. THERE ARE INCREASING HINTS OF BETTER POOLED MOISTURE ALONG THIS BOUNDARY (SEE UPSTREAM DEW POINTS OVER THE SOUTHERN LAKES IN THE LOW 70S)...WHICH COMBINED WITH AT LEAST A LITTLE DAYTIME HEATING AND SUBTLE MID LEVEL HEIGHT FALLS MAY BE ENOUGH TO SUSTAIN THE WARM ADVECTION WING COMPONENT OF THE CURRENT LARGER UPSTREAM MCS. LATEST HRRR GUIDANCE REALLY PICKING UP ON THIS IDEA AND GIVEN CURRENT RADAR MOSAIC...KIND OF HARD TO ARGUE AT THE MOMENT. THIS IS ESPECIALLY TRUE WITH FURTHER HINTS THAT A LOCALIZED LOW LEVEL JET MAXIMUM MAY ALSO POKE INTO THE SOUTHWEST CWA OFF LAKE MICHIGAN...COINCIDENT WITH THE ARRIVAL OF SOMEWHAT BETTER MID LEVEL LAPSE RATES (STILL NOTHING STELLAR) AND BETTER LOW LEVEL THETA-E RIDGING. HAVE RE-WORKED POPS TO SHOW THIS IDEA BETTER. DON`T ANTICIPATE A BIG SEVERE THREAT THROUGH 00Z WITH RATHER SLACK WIND FIELDS (DEEP SHEAR ONLY ABOUT 20 KNOTS) AND LIMITED INSTABILITY (MIXED LAYER CAPE UP AROUND 700 J/KG). UPDATE ISSUED AT 629 AM EDT TUE JUL 9 2013 DENSE FOG HAS EXPANDED OVER THE LAST HOUR OR SO..AND AN SPS HAS BEEN ISSUED FOR LESS THAN A QUARTER OF A MILE VISIBILITIES. THE WORST OF VISIBILITY REDUCTION WAS FOCUSED IN THE COASTAL COMMUNITIES SURROUNDING LAKES MICHIGAN AND HURON. TEMPERATURES WILL BE AT A STAND-STILL FOR THE NEXT SEVERAL HOURS...AS THE STRATUS WILL GO NOWHERE FOR MOST OF THE MORNING. THERE HAVE BEEN NO RAIN SHOWERS FOR THE LAST SEVERAL HOURS...AND NEWER DATA COMING IN...IF ANYTHING...SUGGEST MAYBE EVEN A STRONGER CAP TO PREVENT AFTERNOON SHOWERS AND STORMS. WILL PLAY IT SAFE HERE THOUGH AND KEEP SLIGHT CHANCES IN THE FORECAST...FOR THE MERE FACT THAT WE WILL HAVE DEVELOPED LAKE BREEZES AND A PIECE OF SHORTWAVE ENERGY THAT COULD POSSIBLY OVERCOME CAPPING...ALTHOUGH IT DOESN`T LOOK LIKE IT. BELIEVE THERE WILL BE AFTERNOON SUN...EVENTUALLY FOR TEMPERATURES TO MAKE IT INTO THE 80S....BUT WILL DROP EXPECTED HIGHS A COUPLE DEGREES. && .SHORT TERM...(TODAY THROUGH TONIGHT) ISSUED AT 344 AM EDT TUE JUL 9 2013 CURRENTLY...WEAK LOW PRESSURE WAS WORKING EASTWARD ACROSS NE LOWER...WITH SHOWER ACTIVITY VANISHING AFTER LOSS OF HEATING. MOISTURE HAS BEEN STRIPPED OUT ALOFT AND THE BL REMAINS MOIST. RADIATIONAL COOLING ON TOP OF THIS BL MOISTURE HAS RESULTED IN WIDESPREAD STRATUS...AS FAR OUT AS WISCONSIN. THIS STRATUS WAS ALSO UNDERNEATH A DEVELOPING CAP DUE TO SUBSIDENCE AND SFC HIGH PRESSURE BETWEEN DEPARTING LOW...AND UPSTREAM NEXT LOW PRESSURE AND COLD FRONT. THIS LOW WAS IN FAR NW ONTARIO...WITH ITS COLD FRONT DRAPED DOWN THROUGH NORTH DAKOTA. THERE WAS RELATIVE DRY AIR AND NO PRECIP YESTERDAY WITHIN THE HIGH PRESSURE.TEMPERATURES IN THE STRATUS HAS FLAT-LINED...IN THE UPPER 60S FOR MOST. TODAY...NEW DATA INDICATING THE BL MOISTURE IS QUITE MOIST AND THICK ENOUGH FOR THE SOLID STRATUS TO CONTINUE WELL INTO THE MORNING. WILL KEEP SKIES CLOUDY ALL MORNING...BEFORE HEATING CAN FINALLY RESULT IN HOLES AND A PRETTY GOOD COVERAGE OF CUMULUS. THERE SEEMS TO BE QUITE THE CHANGE IN EXPECTATIONS FOR PRECIPITATION DEVELOPMENT FOR THIS AFTERNOON. A CAP DEVELOPS AT 750MB...VERIFIED BY 00Z UPSTREAM SOUNDINGS ACROSS MINNEAPOLIS/GREEN BAY. USING A PARCEL OF 88/67 WILL RESULT IN ROUGHLY 1400 J/KG SBCAPE AND ONLY A FEW HUNDRED J/KG MLCAPE (WHICH MAY BE BETTER CONSIDERING THE DRYNESS OF THE ENTIRE BL). THUS...CHANCES FOR SEEING ANY SORT OF DIURNAL SHOWERS AND THUNDERSTORMS HAVE DRASTICALLY DWINDLED DUE TO A SIGNIFICANT AMOUNT OF CAPPING/WARM AIR ALOFT. WILL JUST KEEP A 20 PERCENT CHANCE FOR THE LATE AFTERNOON AND EVENING. HIGHS SHOULD MAKE A LATER DAY RUN AT THE MIDDLE AND UPPER 80S. TONIGHT...AFTER ANY DIURNAL CONVECTION WANES...WE WILL BE AWAITING THE MAIN SHOW. THE FAR NRN ONTARIO LOW PRESSURE MOVES EAST AND THE TRAILING COLD FRONT WILL BE MARCHING FROM FAR WESTERN WISCONSIN AND INTO/NEAR EASTERN UPPER/LAKE MICHIGAN BY 12Z. STRONGER SHORTWAVE ENERGY AND NICE UPPER DIVERGENCE SIGNAL WILL WORK IN CONCERT WITH LOW LEVEL CONVERGENCE ASSOCIATED WITH THE FRONT...TO FIRE OFF SHOWERS AND STORMS FOR THE OVERNIGHT. THESE STORMS WILL HAVE BEEN GENERATED ACROSS WISCONSIN IN THE AFTERNOON...BUT EVEN WITH LOSS OF HEATING...THE UPPER FORCING OUGHT TO SUSTAIN THUNDER. MUCAPES ARE PRETTY MINIMAL...IN THE FEW HUNDREDS OR SO...AND WILL DOWNPLAY THE AMOUNT OF THUNDER WITH THE RAIN SHOWERS. THE BETTER/DEEPER INSTABILITY WILL BE WELL SOUTH OF US...IN HIGHER THETA-E AIR ACROSS NRN IL/INDIANA. THE CONVECTION THERE MAY ALSO SERVE TO ROB US OF SOME MOISTURE...ALTHOUGH PWATS ARE EXPECTED TO BE HIGH...1.80" TO ALMOST 2.00" LIQUID. STRATUS AND FOG WILL ALSO BE A CONCERN IN JUICY AIR MASS...BEFORE DRYING SETS IN ON WEDNESDAY. LOWS IN THE MID/UPPER 60S. && .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 344 AM EDT TUE JUL 9 2013 AN UPPER LEVEL TROUGH IN PLACE WEDNESDAY INTO THURSDAY WILL LIFT OUT OF THE REGION AS A LARGE UPPER LEVEL RIDGE CENTERED ACROSS THE DESERT SOUTHWEST EXPANDS NORTHEAST INTO THE GREAT LAKES REGION THURSDAY NIGHT INTO THE WEEKEND. ANOTHER TROUGH MOVING BY TO THE NORTH WILL THEN BEAT DOWN THIS RIDGE EARLY NEXT WEEK. THIS SCENARIO WILL RESULT IN COOLER TEMPERATURES FOR MIDWEEK FOLLOWED BY A WARMING TREND FOR FRIDAY INTO THIS WEEKEND. MEANWHILE...THERE WILL BE MORE CHANCES OF SHOWERS AND THUNDERSTORMS WEDNESDAY...FOLLOWED BY PRECIPITATION FREE WEATHER INTO THE WEEKEND. THERE WILL BE SMALL CHANCES FOR A FEW SHOWERS OR STORMS EARLY NEXT WEEK AS THE TROUGH MOVES BY. THE MAIN LONG TERM FOCUS IS ON LINGERING POPS WEDNESDAY THEN POPS AGAIN NEXT MONDAY. WEDNESDAY...THE SURFACE COLD FRONT CONTINUES TO ADVANCE ACROSS THE REGION FROM NORTHWEST TO SOUTHEAST WITH DRIER AIR ADVECTING IN BEHIND IT. IN ADVANCE OF THE FRONT...THE NAM INDICATES 1000-1500 J/KG OF ML CAPE FROM GAYLORD SE TO GLADWIN THROUGH EARLY AFTERNOON. HOWEVER...THE NAM IS THE MOISTEST MODEL BY FAR WITH THE GFS ET ALL INDICATING LOTS OF DRY AIR ADVECTION (MEAN 1000-500 MB RH FALLING TO ABOUT 40 PERCENT OR SO). THEREFORE WILL LEAVE POPS IN THE CHANCE CATEGORY. POTENTIAL FOR SEVERE STORMS APPEARS LIMITED WITH LIGHT WIND FIELDS ALOFT. HIGHS RANGING FROM AROUND 70 FAR NORTH TO THE LOWER 80S SOUTHEAST. THURSDAY THROUGH MONDAY...THE CORE OF THE UPPER LEVEL COOL POOL IS OVERHEAD (850 MB TEMPS OF PLUS 8 TO 10 C) BUT FAIRLY DRY AIR (MEAN 1000-500 MB RH 30 TO 40 PERCENT) SHOULD INHIBIT DAYTIME HEATING DRIVEN SHOWERS FROM FORMING. OTHERWISE...EXTENDED MODELS CONTINUE TO BE IN GOOD AGREEMENT WITH RIDGING AT THE SURFACE AND SLOWLY BUILDING HEIGHTS ALOFT LEADING TO ANOTHER PLEASANT AND INCREASINGLY WARM STRETCH OF WEATHER INTO THE WEEKEND. AN UPPER LEVEL TROUGH AND ASSOCIATED WEAK COLD FRONT WILL THEN BRING SMALL CHANCES FOR SHOWERS OR THUNDERSTORMS EARLY NEXT WEEK. HIGHS THURSDAY IN THE MIDDLE TO UPPER 70S...FRIDAY IN THE MIDDLE 70S TO LOWER 80S...WITH THE UPPER 70S TO MIDDLE 80S FOR SATURDAY THROUGH MONDAY. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING) ISSUED AT 629 AM EDT TUE JUL 9 2013 IFR CONDITIONS ARE GOING TO CONTINUE THROUGH MUCH OF THE MORNING AS STRATUS AND FOG WILL BE VERY STUBBORN TO LIFT. BL MOISTURE IS FAIRLY SUBSTANTIAL AND HEATING THROUGH IT TO HELP CLEAR SKIES OUT WILL BE MINIMAL FOR AWHILE. DO BELIEVE VFR CONDITIONS WILL DEVELOP LATER THIS AFTERNOON...BUT CHANCES FOR SEEING SHOWERS AND STORMS IN THE AFTERNOON AND EVENING ARE QUITE SMALL...AS WARM AIR ALOFT HAS CAPPED THINGS OFF QUITE WELL. NEWER DATA ROLLING IN FURTHER SUGGEST THINGS WILL BE QUIET. HOWEVER...THE MAIN SHOW WILL STILL BE LATER TONIGHT...LIGHT WINDS EARLY AND THE DEVELOPMENT OF LIGHT FOG IN PERHAPS A PERIOD OF CLEARING...WILL TURN ACTIVE. AN UPSTREAM LOW PRESSURE AND COLD FRONT WILL ARRIVE IN EASTERN UPPER AND LAKE MICHIGAN BY 12Z. SHOWERS AND STORMS OUT AHEAD OF THIS FRONT WILL ROLL THROUGH NW LOWER AROUND 06Z...AND APN AROUND 09Z. THERE IS A SLIGHT CHANCE THAT TVC/MBL COULD SEE A SEVERE STORM...BUT DO BELIEVE THAT THIS IS A VERY SMALL CHANCE. && .MARINE... ISSUED AT 344 AM EDT TUE JUL 9 2013 WINDS WILL CONTINUE TO BE VARIABLE AND LIGHT THROUGH TONIGHT UNDER STABLE CONDITIONS ON THE LAKES. UPSTREAM COLD FRONT WILL APPROACH OVERNIGHT AND INTO WEDNESDAY FOR SHOWERS AND STORMS...AND BEHIND THE FRONT WINDS WILL SHIFT TO OUT OF THE NW. MAYBE HAVE SOME ADVISORY LEVEL GUSTS AT PRESQUE ISLE...SSM/ST MARYS. WINDS WILL LIGHTEN UP OVER TIME THEN...AS HIGH PRESSURE GRADUALLY WORKS IN OVER NRN MICHIGAN LATE THIS WORK WEEK...AND THE WEEKEND. && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LH...NONE. LM...NONE. LS...NONE. && $$ UPDATE...LAWRENCE SYNOPSIS...AS SHORT TERM...SD LONG TERM...AS AVIATION...SD MARINE...SD
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
845 AM EDT TUE JUL 9 2013 LATEST UPDATE... MESOSCALE DISCUSSION .MESOSCALE DISCUSSION... ISSUED AT 844 AM EDT TUE JUL 9 2013 CURRENTLY (830 AM) THERE ARE TWO LINES OF THUNDERSTORMS HEADED TOWARD SOUTHWEST LOWER MICHIGAN. IF THE LINE CONTINUED TO PROGRESS AS IT IS... IT WOULD REACH HOLLAND AROUND 2 PM THIS AFTERNOON. HOWEVER LOOKING AT RAP MODEL SOUNDINGS WE STILL HAVE A SIGNIFICANT DRY LAYER FROM 6000 FT TO 15000 FT THAT WOULD HAVE TO BE OVERCOME. ALSO THE AREA OF SATURATED LIFT IN THE DGZ ON THE RAP MODEL NEARLY PERFECTLY MATCHES THE LIGHTING ACTIVITY OVER THE PAST 4 HOURS... AND THAT AREA DOES NOT REACH SOUTHWEST LOWER MICHIGAN THROUGH 5 PM. ACTUALLY THE NORTHERN AREA HEADS TOWARD THE UPPER PENINSULA AND THE SOUTHERN AREA HEADS TOWARD CHI AND MKE. ALSO THE LOW LEVEL JET WEAKENS AS IT COMES TOWARD SOUTHWEST LOWER MICHIGAN. BOTH THE HRRR AND RAP MODEL DO NOT BRING THE THUNDERSTORMS INTO OUR CWA THROUGH 5 PM. THE HRR TAKES THE SOUTHERN AREA INTO BERRIEN COUNTY AROUND 6 PM. ONE OTHER ASPECT TO THIS IS THE DEEP LAYER SHEAR IS UNDER 20 KNOTS THROUGH 8 PM OVER ALL OF THE SOUTHERN 2/3 OF LOWER MICHIGAN SO THAT WILL HELP TO KEEP THE STORMS FROM GETTING TO ORGANIZED. SO MY SPIN ON THIS IS THAT LINE... IF IT GETS HERE WILL BE RATHER WEAK AND DISSIPATING DUE TO THE CAP CREATED BY THE DEEP DRY LAYER. THERE COULD BE SOME STRONG STORMS OVER OUR EXTREME SOUTHWEST COUNTIES TOWARD DINNER TIME. && .SYNOPSIS... ISSUED AT 335 AM EDT TUE JUL 9 2013 MOST OF THE DAY TODAY SHOULD SEE A GOOD DEAL OF SUNSHINE AND VERY WARM AND HUMID TEMPERATURES AFTER MORNING LOW CLOUDS AND FOG DISSIPATE. THERE WILL BE A SLIGHT CHANCE OF A STORM DURING THE AFTERNOON HOURS. THE BETTER CHANCE OF MORE WIDESPREAD SHOWERS AND STORMS WILL COME TOWARD AND AFTER MIDNIGHT TONIGHT AS A WAVE OF LOW PRESSURE MOVES THROUGH THE AREA. THE CHANCE OF RAIN WILL DIMINISH THROUGH THE DAY ON WEDNESDAY AS A COLD FRONT PUSHES SOUTH THROUGH THE AREA. TEMPERATURES WILL BE A BIT COOLER WEDNESDAY AFTERNOON. EVEN COOLER TEMPERATURES AND DRY CONDITIONS WILL BE FOUND FOR THE REMAINDER OF THE WEEK BEFORE WE START TO WARM UP AGAIN THIS COMING WEEKEND. && .SHORT TERM...(TODAY THROUGH THURSDAY) ISSUED AT 335 AM EDT TUE JUL 9 2013 THE MAIN ISSUE IN THE SHORT TERM IS FOG THIS MORNING...THEN STORM POTENTIAL AND SEVERE THREAT FOR LATE TODAY AND TONIGHT. A FAIR AMOUNT OF FOG AND LOW CLOUDS HAVE DEVELOPED OVER THE NRN SECTION OF THE CWFA EARLY THIS MORNING. SOME OF THIS IS STARTING TO DEVELOP FURTHER SOUTH AS A WEAK SFC TROUGH CRAWLING SOUTH ACROSS THE AREA IS LIKELY BEING OVERRUN A BIT JUST OFF THE SFC AND WITH THE HUMID AIR MASS IN PLACE. WE DO EXPECT THAT THIS WILL DISSIPATE DURING THE MID MORNING HOURS AS THE STRONG SUN ANGLE WORKS ON THE SHALLOW LAYER OF MOISTURE. WE EXPECT TO SEE A GOOD DEAL OF SUNSHINE AFTER THE LOW CLOUDS AND FOG DISSIPATE. THE AREA WILL BE UNDER THE INFLUENCE OF SHORT WAVE RIDGING ALOFT BETWEEN THE DEPARTING WAVE FROM YESTERDAY AND THE NEXT WAVE EXPECTED TONIGHT. FCST SOUNDINGS SHOW A WARM LAYER BETWEEN 850-700MB THAT SHOULD CAP MOST IF NOT ALL CONVECTIVE DEVELOPMENT THROUGH ALMOST 00Z. WE CAN NOT RULE OUT AN ISOLATED SHOWER/STORM DEVELOPING ALONG A BOUNDARY LIKE A LAKE BREEZE. THAT SAID...THE LOW LEVEL FLOW LOOKS FAIRLY DIVERGENT DURING THE DAY TODAY WHICH SHOULD LIMIT ANY DEVELOPMENT ALSO. THE AREA STILL LOOKS LIKE IT IS ON TRACK FOR A BATCH OF SHOWERS AND STORMS TO MOVE THROUGH TONIGHT. THE BEST CHANCE WILL OCCUR ALONG AND SOUTH OF INTERSTATE 96. OUR FOCUS IS ON THE SHORT WAVE PRODUCING CONVECTION ACROSS THE DAKOTAS...AND THE EVENTUAL LLJ THAT IS EXPECTED TO DEVELOP THIS EVENING/OVERNIGHT. WE DO EXPECT THE SHORT WAVE TO MOVE INTO THE AREA TOWARD 06Z. IT SEEMS THAT THE CONVECTION ACROSS THE DAKOTAS SHOULD SLOWLY MOVE THROUGH THE DAY. WE COULD SEE IT INTENSIFY A BIT IN WISCONSIN THIS AFTERNOON AS IT ENCOUNTERS BUILDING INSTABILITY THERE. THIS LINE WILL LIKELY DIMINISH SOME AS IT HEADS TOWARD OUR CWFA TONIGHT WITH THE LOSS OF DIURNAL INSTABILITY. WHAT WE WILL SEE IS THE LLJ INCREASE A BIT AND THE NOSE BE AIMED AT THE SRN HALF OF THE CWFA BY 06Z. THIS SHOULD HELP MAINTAIN A FAIRLY DECENT AREA OF SHOWERS AND STORMS THAT WOULD LAST INTO THE DAYBREAK HOURS ON WED BEFORE MOVING OUT. SEVERE THREAT DOES NOT SEEM VERY IMPRESSIVE DUE TO THE LATE NIGHT TIME FRAME THE CONVECTION WOULD BE MOVING IN. FCST SOUNDINGS INDICATE THAT THE CAPE IN THE -10 TO -30C LAYER IS NOT REAL ABUNDANT. DEEP LAYER CLOUD LAYER SHEAR IS ON THE LOWER SIDE AROUND 20-25 KNOTS OR SO. MOST OF THE STORMS WOULD BE ELEVATED WITH SOME POSSIBILITY OF SOME WINDS MAKING IT DOWN WITH SOME RESIDUAL LOW LEVEL INSTABILITY. WE FEEL THAT IF THE STORMS MOVE THROUGH AS EXPECTED TONIGHT...MOST OF THE CWFA WILL BE WORKED OVER ENOUGH FOR WED THAT THE THREAT OF STORMS AND SEVERE WEATHER IS LOW. IT WILL TAKE A WHILE TO BUILD UP THE INSTABILITY...AND THE FRONT SHOULD CLEAR THE CWFA BY PEAK HEATING. THE BEST CHC FOR STORMS WILL BE DOWN SOUTH WHERE LOCATIONS DO NOT SEE MCS ACTIVITY TONIGHT. WE WILL SEE SKIES CLEAR THEN WED EVENING AND CONTINUE THROUGH THU AS DRIER AND COOLER AIR MOVES IN. A SHORT WAVE DOES MOVE THROUGH FROM THE NW ON THU...HOWEVER THE AIR SHOULD BE DRY ENOUGH AND WE WILL BE ON THE DOWNSTREAM SIDE OF THE LONG WAVE RIDGE TO OUR WEST TO KEEP US DRY. .LONG TERM...(THURSDAY NIGHT THROUGH MONDAY) ISSUED AT 335 AM EDT TUE JUL 9 2013 THE ARRIVAL OF MID LEVEL RIDGING EARLY IN THE PERIOD SUPPORTS A DRY PATTERN FOR THE REGION THEN. SUBSIDENCE IS SEEN ON BUFKIT OVERVIEWS AND MOISTURE PROFILES REMAIN DRY THROUGH SAT. A WARM AIR ADVECTION PATTERN SETS UP BY SUNDAY AND PWAT VALUES WILL BE ON THE INCREASE. A WEAKENING SURFACE FRONT SLIPS DOWN FROM THE NORTHWEST SUNDAY NIGHT INTO MONDAY. WITH SOME ELEVATED/SURFACE INSTABILITY ALONG OR AHEAD OF THE FRONTAL ZONE...THERE COULD BE A FEW STORMS. THE BELOW NORMAL TEMPERATURES TO START THE PERIOD TRANSITION TO ABOVE NORMAL VALUES FOR THE END OF THE PERIOD. TEMPERATURE VALUES AT 925 MB CLIMB INTO THE LOW TO MID 20 DEG C RANGE SUNDAY. WITH SOME SUN...WE SHOULD EASILY REACH THE MID 80S. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING) ISSUED AT 739 AM EDT TUE JUL 9 2013 LOW CLOUDS WILL BE SLOW DO DISSIPATE ESPECIALLY CLOSER TO THE LAKESHORE THIS MORNING. IMPACTS TO PERSIST WITH IFR/LIFR COMMON TO START. BY 16Z CONDITIONS AT MOST SITES SHOULD BE MVFR. LINE OF STORMS TRACKING THROUGH NRN IOWA WILL ARRIVE IN WRN MI AFTER 19Z IF THEY SURVIVE. UNSTABLE CONDITIONS PERSIST MUCH OF THE NIGHT. SO TAFS WILL FEATURE THE POSSIBILITY OF A STORM THROUGH THE EVENING. && .MARINE... ISSUED AT 335 AM EDT TUE JUL 9 2013 NO HEADLINES WILL BE ISSUED WITH THIS FCST PACKAGE...HOWEVER WE ARE LOOKING AT FOG POTENTIAL THROUGH TONIGHT...ROUGH WEATHER TONIGHT WITH A POSSIBLE ROUND OF STORMS...AND THEN SOME DECENT WINDS POSSIBLE WED BEHIND THE FRONT. THE LIGHT GRADIENT OVER THE LAKE THIS MORNING ALONG WITH THE HUMID AIR MASS OVER THE SOMEWHAT COOL WATER IS LIKELY PRODUCING SOME FOG. WEBCAMS SHOW SOME PLACES SEEING FOG WHILE OTHERS ARE NOT. WE DO NOT FEEL CONFIDENT ENOUGH AT THIS TIME TO ISSUE A MARINE FOG ADVISORY... HOWEVER IT IS SOMETHING WE WILL NEED TO MONITOR. WINDS AHEAD OF THE WAVE MOVING IN TONIGHT WILL HAVE THE POTENTIAL TO INCREASE THE WINDS AND WAVES SOME TONIGHT. THE BIGGER THREAT WILL LIKELY BE THE STORMS THAT ARE ANTICIPATED. THE BEST WIND WILL COME WITH ANY STORMS. A DECENT NW WIND COULD DEVELOP LATE WED AFTERNOON BEHIND THE FRONT THAT PUSHES THROUGH. A SMALL CRAFT ADVISORY MAY BE NEEDED FOR THAT PERIOD. && .HYDROLOGY... ISSUED AT 335 AM EDT TUE JUL 9 2013 THE MAIN PERIOD OF CONCERN AS FAR AS HYDRO IS CONCERNED IS THE TONIGHT PERIOD. WE WILL SEE PRECIPITABLE WATER INCREASE TO AROUND 2.00 INCHES THIS EVENING AHEAD OF THE WAVE THAT WILL MOVE THROUGH THE AREA. THIS WILL PROVIDE THE POTENTIAL OF HEAVY DOWNPOURS ACROSS THE AREA. WE DO NOT ANTICIPATE SIGNIFICANT WIDESPREAD ISSUES AS THIS WAVE THAT MOVES THROUGH SHOULD BE RATHER PROGRESSIVE. AMOUNTS WILL LIKELY BE A QUARTER TO THREE QUARTERS OF AN INCH OF RAINFALL FOR BASIN AVERAGES...WITH SOME LOCAL AREAS SEEING 1-2 INCHES OF RAIN. URBAN AND SMALL STREAM ISSUES WILL BE THE MAIN THREAT. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. && $$ MESOSCALE...WDM SYNOPSIS...NJJ SHORT TERM...NJJ LONG TERM...MJS AVIATION...MJS HYDROLOGY...NJJ MARINE...NJJ
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
733 AM EDT TUE JUL 9 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 525 AM EDT TUE JUL 9 2013 WV IMAGERY AND RUC ANALYSIS INDICATED A MAINLY ZONAL PATTERN ACROSS THE NRN CONUS WITH SEVERAL UPSTREAM SHORTWAVE TROUGHS. THE MOST PROMINENT SHRTWV WAS LOCATED OVER ERN MT WHILE A WEAKER IMPULSE AND ASSOCIATED MCS WAS MOVING THROUGH ERN SD. AT THE SFC...A WEAK FRONTAL BOUNDARY LINGERED ACROSS SRN WI WHILE A STRONGER COLD FRONT AHEAD OF THE MT SHRTWV EXTENDED FROM NW ONTARIO INTO NRN ND. A WEAK RIDGE EXTENDED FROM QUEBEC ACROSS LAKE SUPERIOR RESULTING IN LIGHT/CALM WINDS OVERNIGHT. AREAS OF FOG...LOCALLY DENSE...HAS DEVELOPED AS ABUNDANT LOW LEVEL MOISTURE LINGERED BELOW AN INVERSION ABOVE 850 MB. EXPECT THAT THE MORNING WILL BE DOMINATED BY LOW CLOUDS BUT WITH DAYTIME HEATING/MIXING THE LOW CLOUDS ACROSS MOST OF THE AREA WILL THIN OUT ENOUGH BY THIS AFTERNOON FOR TEMPERATURES TO CLIMB INTO THE LOWER 80S INLAND. SATELLITE TRENDS...SHORTER TERM MODELS AND CAPE GRADIENT...SUGGEST THAT THE ERN SD MCS WILL TRACK TO THE EAST INTO W AND SRN WI. THERE IS SOME UNCERTAINTY REGARDING THE IMPACTS OF THE MCS ON CONVECTION DEVELOPING FARTHER TO THE NORTH. THE FORCING ASSOCIATED WITH THE APPROACHING NRN PLAINS SHRTWV WITH 100M HEIGHT FALLS AND MODERATE 700-300 QVECTOR CONV WILL ALSO BE STRONGEST TO THE NORTH OF THE CWA. HOWEVER...THE SRN END OF THE SHRTWV SHOULD STILL BE STRONG ENOUGH TO SUPPORT SCT SHRA/TSRA MOVING FROM NW WI INTO WRN UPPER MI THIS AFTERNOON AND THROUGH THE REST OF THE CWA THIS EVENING. EXPECTED MAX TEMPS AND DEWPOINTS INTO THE MID TO UPPER 60S GIVE CAPE VALUES INTO THE 1K-2K J/KG RANGE...GREATEST WEST CENTRAL. 0-6KM BULK SHEAR VALUES IN THE 30-35 KNOT RANGE WILL BE MARGINAL FOR STRONG/SVR ORGANIZED CONVECTION BUT WITH TSRA MOVING THROUGH DURING PEAK HEATING GIVING DCAPE VALUES IN THE 500-1000 J/KG RANGE...SOME ISOLATED STRONG/DAMAGING WIND GUSTS MAY BE POSSIBLE WITH ANY STRONGER STORMS. THE HIGHER PROBABILITIES FOR SVR STORMS REMAINS TO THE SOUTH WHERE THE INSTABILITY IS GREATEST...PER SPC DAY1 OUTLOOK. THE SHRA/TSRA ARE EXPECTED TO PROGRESS THROUGH THE AREA MOVING INTO THE ERN CWA LATE THIS EVENING AND ENDING OVERNIGHT. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 525 AM EDT TUE JUL 9 2013 AFTER A FEW DAYS OF WARM AND ACTIVE WEATHER WITH POCKETS OF HEAVY RAIN OVER MAINLY WESTERN HALF OF CWA...DEVELOPING TROUGHING ALOFT ACROSS THE GREAT LAKES AND SFC HIGH ON THE WESTERN EDGE OF THE TROUGH ALOFT WILL BRING QUIET AND COOLER WEATHER MID TO LATE WEEK. WARMER TEMPERATURES AND INCREASING SHRA/TSRA CHANCES RETURN FOR THE WEEKEND AS UPPER HEIGHTS BECOME MORE ZONAL. OVERALL AGREEMENT THAT BEST CHANCE OF SHRA/TSRA ON WEDNESDAY WILL BE 12-15Z OVER THE FAR EASTERN CWA. STRONGER TSRA STILL POSSIBLE WITH MUCAPE UP TO 800J/KG. BETTER SHOT FOR SVR WILL BE FARTHER SOUTH OVER SOUTHERN WI/NORTHERN IL CLOSER TO WEST-EAST FRONTAL BOUNDARY AND ON NORTHERN GRADIENT OF HIGHER MLCAPES OVR 1000J/KG. ANY CHANCES OF SHRA/TSRA OVER EAST QUICKLY END THROUGH MORNING AS STRONG DEEP LAYER Q-VECTOR DIVERGENCE/SUBSIDENCE SURGES ACROSS UPPER GREAT LAKES. PRESSURE GRADIENT BRIEFLY BECOMES TIGHT BTWN THE EXITING LOW PRESSURE TROUGH AND HIGH PRESSURE BUILDING OVER THE PLAINS. EXPECT BRIEF BUILDING WAVES AND INCREASED SWIM RISK FOR WEDNESDAY OVER THE LK SUPERIOR BEACHES OF ALGER COUNTY AS WINDS WILL BE FROM THE WEST TO NORTHWEST. WINDS/WAVES AND ASSOCIATED HIGHER SWIM RISK SUBSIDES BY LATE AFTN WITH LOSS OF PRESSURE RISES AND TIGHTER PRESSURE GRADIENT. HIGH PRESSURE REMAINS MAIN WEATHER FEATURE FOR THU/FRI. TEMPS MAY DROP INTO THE LOW-MID 40S OVER INTERIOR COOL SPOTS ON THURSDAY NIGHT WITH LGT SOUTHERLY FLOW AS RIDGE AXIS DRIFTS ACROSS. AIRMASS DOES NOT APPEAR TO BE NEARLY COLD OR DRY ENOUGH FOR ANY FROST POTENTIAL. HIGH TEMPS BOTH DAYS SHOULD TOP OUT IN THE MID-UPR 70S AWAY FROM THE GREAT LAKES. MAY EVEN SEE A FEW SPOTS BACK NEAR 80 DEGREES BY THURSDAY. UNCERTAINTY ABOUNDS WITH TIMING AND EXTENT OF NEXT ROUND AND/OR ROUNDS OF SHRA/TSRA THIS WEEKEND INTO NEXT MONDAY. ECMWF NORMALLY LEADS WAY IN TERMS OF VERIFICATION...BUT BOY ARE ITS SOLUTIONS IN THE LAST COUPLE DAYS QUITE INCONSISTENT IN TERMS OF TIMING FOR THE WEEKEND SHRA/TSRA CHANCES. DOES SEEM LIKE ECMWF IS TRENDING TOWARD SLOWER IDEA SHOWN BY GFS FOR ARRIVAL OF PRECIP FRIDAY NIGHT. WILL START TO SHOW TREND OF CHANCE POPS ONLY OVER THE FAR WEST LATE ON FRIDAY NIGHT WHILE IT STAYS MAINLY DRY ELSEWHERE. UPPER HEIGHTS FLATTEN OUT SATURDAY ALLOWING SHORTWAVES AND MID-LEVEL WIND MAX TO SLIDE ACROSS UPPER GREAT LAKES REGION. MAIN SFC LOW WILL BE WELL TO NORTH CLOSER TO SHARPER TROUGH ALOFT...BUT SW LOW-LEVEL FLOW ALONG WITH INCREASING MOISTURE AND BUILDING INSTABILITY JUST UPSTREAM SHOULD RESULT IN AT LEAST A CHANCE OF SHRA/TSRA AHEAD OF SFC-H85 TROUGH THAT MOVES THROUGH BY SUNDAY MORNING. WITH WRLY FLOW ALOFT...FRONT MAY END UP STALLING OUT LATER IN THE WEEKEND PROVIDING A FOCUS FOR ADDITIONAL SHRA/TSRA. FOR MOST PART USED CONSENSUS POPS...BUT DID INCREASE POPS SLIGHTLY OVER THE SOUTH AND EAST CWA CLOSER TO EXPECTED POSITION OF FRONT PER WPC HAND DRAWN SFC PROGS. BASED ON GENERAL S/SW GRADIENT FLOW AHEAD OF FRONT AND H85 TEMPS IN THE MID TEENS...INCREASED TEMPS OVER CONSENSUS GUIDANCE. EXPECT MAX TEMPS FRIDAY THROUGH SUNDAY IN THE MID-UPR 70S TO AS WARM AS MID 80S. IT WILL ALL DEPEND ON EXTENT OF CLOUDS AND SHRA/TSRA. AFTER MIN TEMPS IN THE 40S AND 50S MUCH OF THIS WEEK...READINGS RETURN TO THE WARMER/MUGGIER 60S BY THE WEEKEND. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING) ISSUED AT 733 AM EDT TUE JUL 9 2013 EXPECT DENSE FOG/VLIFR CONDITIONS TO IMPACT CMX/SAW EARLY TODAY MRNG WITH LGT WINDS/HUMID LLVLS UNDER SFC HIGH PRES/DRIER AIR ALOFT. DIURNAL HEATING SHOULD ALLOW A GRADUAL RETURN OF VFR WX. SOME SHRA/TS IN ADVANCE OF A SHORTWAVE AND COLD FRONT WILL ARRIVE OVER THE WRN IWD/CMX BY LATE AFTERNOON AND THEN MOVE E TOWARD SAW DURING THE EVENING. ALTHOUGH THE RELATIVE DRYNESS OF THE LOW LEVELS SHOULD ALLOW PREDOMINANT VFR CONDITIONS...POORER CONDITIONS WILL BE POSSIBLE UNDER THE HEAVIER SHRA/TS. UPSLOPE WNW FLOW OFF LAKE SUPERIOR IN THE WAKE OF THE CONVECTION MIGHT CAUSE PREDOMINANT MVFR WX AT CMX...ESPECIALLY IF HEAVIER RA FALLS NEARBY. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 359 PM EDT MON JUL 8 2013 DENSE FOG REMAINS A CONCERN ACROSS LAKE SUPERIOR THROUGH TUESDAY MORNING. LIGHT WINDS AND LITTLE AIR MASS MOVEMENT WILL ALLOW FOR THE REDEVELOPMENT OF AREAS OF DENSE FOG OVERNIGHT. CLEARING SKIES FOR TUESDAY MORNING SHOULD ALLOW ENOUGH HEATING TO MIX OUT THE MOST DENSE FOG BY TUESDAY AFTERNOON. PATCHY FOG WILL THEN LINGER INTO WEDNESDAY BEFORE A COLD FRONT BRINGS DRIER AIR FROM WEST TO EAST ACROSS THE LAKE. WINDS SHOULD BE LIGHT AND GENERALLY VARIABLE THROUGH TUESDAY EVENING. THEN...EXPECT WINDS TO VEER TO THE NW AT 15 TO 25 KNOTS...MAINLY ACROSS THE EAST HALF OF THE LAKE...FOR LATE TUESDAY NIGHT THROUGH WEDNESDAY. HIGH PRESSURE WILL THEN BUILD INTO THE AREA THURSDAY THROUGH SATURDAY AND BRING LIGHT WINDS UNDER 15 KNOTS FOR MUCH OF THE TIME PERIOD. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... DENSE FOG ADVISORY UNTIL 5 PM EDT /4 PM CDT/ THIS AFTERNOON FOR LSZ162-240>251-263>267. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...JLA AVIATION... MARINE...KLUBER
AREA FORECAST DISCUSSION
NWS DULUTH MN
923 AM CDT TUE JUL 9 2013 .UPDATE... FOCUS IN THE SHORT TERM IS COVERAGE OF RAIN/STORMS AND THEIR INTENSITY. A LINE OF STRONG-SEVERE STORMS WERE MOVING INTO WEST CENTRAL/NORTHWEST WISCONSIN AS OF MID MORNING...WITH A KMPX RADAR SHOWING A A NICE AREA OF OUTBOUND VELOCITY FROM 50-60 KT AT TIMES. THIS LINE WAS MOVING EAST/NORTHEAST 40-45 MPH. AN AREA OF RAIN WITH SOME EMBEDDED STORMS EXTENDED NORTH INTO NORTHWEST MINNESOTA/MANITOBA/NORTHWEST ONTARIO AS WELL. RADAR TRENDS SHOW A DIMINISHING TREND IN WHAT WAS A MORE ORGANIZED AREA OF SHOWERS/STORMS WITH FEW RETURNS HEADED FOR THE IRON RANGE/ARROWHEAD. THE FRONT AND MAIN SHORTWAVE ARE STILL WEST/NORTHWEST OF THE CWA...SO THERE IS AMPLE LIFT THAT NEEDS TO MOVE THROUGH THE NORTHLAND YET TODAY AND THAT WILL LEAD TO ADDITIONAL CHANCES FOR STORMS THROUGH THE DAY. WE WILL CONTINUE TO MAKE SHORT TERM ADJUSTMENTS TO GRIDS ACCOUNTING FOR RADAR TRENDS. THE NAM SUGGESTS COVERAGE SHOULD INCREASE THROUGH THE DAY. THE 12Z KMPX/KINL SOUNDINGS EACH HAD PWAT VALUES OF 1.75 AND 1.41 INCHES. SPC MESOANALYSIS DEPICTED AROUND 30KT DEEP LAYER SHEAR WITH 500-1500J/KG OF MUCAPE. 11Z HRRR WAS DOING AN OK JOB DEPICTING 14Z RAIN/STORMS...AND ALSO SHOWS THE RAIN SPLITTING WITH ADDITIONAL SCATTERED SHOWERS/STORMS DEVELOPING THIS AFTERNOON INTO THE EVENING. SHORT TERM SEVERE THREAT WILL BE OVER OUR NORTHWEST WISCONSIN ZONES OVER THE NEXT 1 TO 3 HOURS...THEN SHIFTS AHEAD OF THE FRONT THIS AFTERNOON AS IT MOVES THROUGH THE CWA. && .PREV DISCUSSION... /ISSUED 621 AM CDT TUE JUL 9 2013/ AVIATION.../12Z TAF ISSUANCE/ EARLY MORNING LIFR/IFR CONDITIONS DUE TO FOG ACROSS PARTS OF NE MINNESOTA AND NW WISCONSIN...INCLUDING KDLH AND KHIB...SHOULD LIFT AND BREAK UP WITHIN THE NEXT FEW HOURS. SHOWERS AND THUNDERSTORMS ARE LIKELY ACROSS THE NORTHLAND TODAY AND EARLY THIS EVENING. THE SHOWERS AND STORMS COULD BRING BRIEF MVFR CONDITIONS DUE TO LOW CIGS AND VSBY RESTRICTIONS FROM RAIN. THE REGION WILL BEGIN TO CLEAR THIS EVENING AS HIGH PRESSURE BEGINS TO MOVE INTO THE NORTHERN PLAINS AND UPPER MIDWEST. EXPECT VFR CONDITIONS LATE THIS EVENING AND WEDNESDAY MORNING. THE VERY LIGHT WINDS WILL INCREASE LATE THIS AFTERNOON AND THIS EVENING AND BECOME NW IN THE WAKE OF A PASSING COLD FRONT. PREV DISCUSSION... /ISSUED 453 AM CDT TUE JUL 9 2013/ SHORT TERM...TODAY AND TONIGHT. CURRENT REGIONAL RADAR IMAGERY SHOWS A LARGE AREA OF SHRA/TSTORMS ASSOCIATED WITH A MID-LEVEL TROUGH EXTENDING FROM SRN MANITOBA...ALONG THE WESTERN MN BORDER...INTO IOWA. AT THIS TIME...THE STRONGEST STORMS...LOCATED WITH A STRENGTHEN MCS...IS FOUND EXITING EASTERN SD AND MOVING INTO THE SW PORTION OF MN. LATEST HIGH RES MODEL RUNS OF THE WRF/HRRR HAVE A RELATIVELY DECENT HANDLE ON THE CURRENT CONVECTION AND BOTH SHOW THE STORMS DECREASING SOMEWHAT...BUT OVERALL HOLDING TOGETHER AS THE LINE MARCHES EAST ACROSS MINNESOTA THIS MORNING. HAVE ADJUSTED POPS THIS MORNING TO LIKELY USING THE CURRENT DISTANCE/SPEED OF THE LINE OF STORMS FOR TIMING. AT THE CURRENT SPEED...THE LEADING EDGE OF THESE STORMS WILL ARRIVE IN THE KINL TO KBRD AREA AROUND 700 TO 800 AM...REACHING A LINE FROM KHIB TO KDLH AND EXTENDING SOUTH ALONG THE INTERSTATE 35 CORRIDOR AROUND 10-11 AM. THE LIMITING FACTOR WILL BE IF THE MCS TRACKING ACROSS CENTRAL MINNESOTA CUTS OFF THE MOISTURE TO STORMS FURTHER NORTH. SHIFTING FOCUS TO ADDITIONAL THUNDER DEVELOPMENT THIS AFTERNOON ALONG A SFC COLD FRONT. THE SEVERITY AND COVERAGE OF THE AFTERNOON CONVECTION WILL BE HIGHLY DEPENDENT ON THE HOW WORKED OVER THE REGION BECOMES WITH THE STORMS THIS MORNING. HAVE BROADBRUSH SCT THUNDER OVER MN ZONES...WITH LIKELY ACROSS THE TIP OF THE ARROWHEAD AND NRN WIS AREAS THROUGH THIS EVENING. LONG TERM [WEDNESDAY - MONDAY] THE BEGINNING OF THE PERIOD LOOKS RELATIVELY QUIET. HIGH PRESSURE AND NW FLOW SHOULD PROVIDE MILD WEATHER AND SUNNY SKIES ACROSS THE NORTHLAND. WE EXPECT A WARMING TREND LATE THIS WEEK...LIKELY CULMINATING ON FRIDAY...AS A MID/UPPER LEVEL RIDGE BUILDS INTO THE UPPER MIDWEST AND SOUTHERLY WINDS INCREASE ACROSS THE NORTHLAND. MUCH OF THE NORTHLAND...SAVE THE IMMEDIATE NORTH SHORE...SHOULD HAVE TEMPERATURES AT LEAST IN THE LOW TO MID 80S ON FRIDAY. I INCREASED THE FRIDAY HIGH TEMPERATURES SINCE I THINK THE MOS GUIDANCE IS TOO WEIGHTED TOWARDS CLIMATOLOGY...AND WE MIGHT NEED TO INCREASE EVEN THE HIGHS EVEN MORE. A COLD FRONT WILL APPROACH THE NORTHLAND LATE THIS WEEK AND THEN MIGHT STALL OR SLOWLY PROGRESS THROUGH THE REGION THROUGH EARLY NEXT WEEK. THIS WILL BRING A PERIOD OF SEVERAL DAYS WHERE THE NORTHLAND WILL HAVE CHANCES OF SHOWERS AND THUNDERSTORMS. FOR NOW...LATE FRIDAY NIGHT AND SATURDAY MORNING APPEARS TO BE THE PERIOD IN WHICH THE NORTHLAND WILL HAVE THE GREATEST CHANCES OF SHOWERS AND STORMS. THE MODELS ARE IN FAIRLY GOOD AGREEMENT THAT THE APPROACHING/PASSING COLD FRONT WILL BRING WIDESPREAD RAINFALL OF AT LEAST A TENTH TO QUARTER INCH OF RAIN TO THE NORTHLAND. && .POINT TEMPS/POPS... DLH 73 55 76 54 / 60 40 0 0 INL 76 54 77 50 / 70 10 0 0 BRD 83 56 79 56 / 70 20 0 0 HYR 83 57 80 51 / 70 60 0 0 ASX 74 55 76 52 / 70 60 0 0 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...DENSE FOG ADVISORY UNTIL NOON CDT TODAY FOR MNZ020-021-037. WI...DENSE FOG ADVISORY UNTIL NOON CDT TODAY FOR WIZ001>003. LS...DENSE FOG ADVISORY UNTIL 4 PM CDT THIS AFTERNOON FOR LSZ121- 140>148. && $$ SHORT TERM...MELDE
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
710 AM CDT TUE JUL 9 2013 .UPDATE... 12Z AVIATION DISCUSSION ADDED BELOW. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 410 AM CDT TUE JUL 9 2013 MAIN CONCERN IN THE SHORT TERM REVOLVES ON EVOLUTION OF STORMS CURRENTLY ACROSS THE DAKOTAS THROUGH THE MORNING...FOLLOWED BY WHERE THUNDERSTORMS REDEVELOP THIS AFTERNOON AND TRAVEL THIS EVENING. IT IS THE AFTERNOON/EVENING ACTIVITY THAT WILL ALSO HAVE A SEVERE THREAT. WIND AND HAIL WILL BE THE PRIMARY THREATS...THOUGH DEPENDING ON WHERE BOUNDARIES ARE LEFT OVER FROM CONVECTION THIS MORNING...THERE WILL ALSO BE THE SMALL CHANCE FOR TORNADOES ON ANY LEFT OVER OUTFLOW BOUNDARIES. AT 3 AM...WE WERE DEALING WITH A BIFURCATED LLJ IN TERMS OF MOISTURE TRANSPORT MAXIMA...WITH ONE BRANCH DRIVING CONVECTION CURRENTLY MOVING ACROSS THE DAKOTAS AND THE OTHER DRIVING ANOTHER CLUSTER ALONG THE NEB/IA BORDER. THIS SRN BRANCH WILL TRACK ACROSS IA THROUGH THE MORNING...KEEPING THAT CONVECTION SOUTH OF MN WHILE BECOMING THE MAIN LLJ FOR POTENTIAL AFTERNOON ACTIVITY. FOR THE MPX AREA...IT IS THE MCS THIS MORNING OVER SODAK THAT WILL BE OUR PROBLEM. 3Z RAP MUCAPE ANALYSIS SHOWS A RIBBON OF 1000-1500 J/KG OF MUCAPE EXTENDING FROM THE MADISON/CANBY AREA...ESE TROUGH ROCHESTER AND LA CROSSE. AS A RESULT...ANTICIPATE THIS BAND OF THUNDERSTORMS WILL CONTINUE ESE ALONG THIS CAPE GRADIENT. AT ITS CURRENT PACE...SHOULD ENTER WRN MN SHORTLY BEFORE 5 AM...REACH THE I-35 CORRIDOR BETWEEN 7 AND 8 AM AND EVENTUALLY THE LSE/EAU AREAS BY LATE MORNING. THE BULK OF THE CONVECTION WITH THIS LINE SHOULD TRACK SOUTH OF I-94 THIS MORNING. AS FOR SEVERE THREAT...THE STRONG/SEVERE LINE OF STORMS THAT MOVED ACROSS SODAK HAS NOW MERGED WITH THE WAA ACTIVITY THAT HAD DEVELOPED OUT AHEAD OF IT...WITH ONE LINE NOW EVIDENT ON REGIONAL RADAR ANALYSIS. WILL HAVE TO WATCH HOW THIS LINE EVOLVES OVER THE NEXT HOUR TO SEE WHAT KIND OF SEVERE THREAT IT WILL POSE. IN THE NEXT HOUR...IF IT BEGINS TO BOW OUT AND ACCELERATE...THEN A WIND THREAT WILL EXIST THROUGH THE MORNING AS IT TRACKS ACROSS MN. WITH THE RAP AT 3Z ANALYZING 20-30 KTS OF 0-3KM SHEAR OUT AHEAD OF THE SYSTEM...IT IS PLAUSIBLE THAT THAT COULD HAPPEN...THOUGH IN THE END IT MAY BE DIFFICULT TO GET ANY SEVERE STRENGTH WINDS THROUGH THE STABLE BOUNDARY LAYER...SO AGREE WITH SPC MCD THAT SEVERE THREAT WILL BE FAIRLY MARGINAL. FOR THIS AFTERNOON...MANY A QUESTION MARKS STILL REMAIN IN PLACE. THIS BIGGEST ISSUE IS HOW WILL STORMS THIS MORNING IMPACT WHAT HAPPENS LATER. THE MAIN QUESTION IS DOES THE ATMOSPHERE HAVE ENOUGH TIME TO RECHARGE FROM STORMS MOVING THROUGH LARGELY IN THE 10-18Z TIME FRAME? FIRST WORD OF WARNING FOR THE ARM CHAIR FORECASTERS OUT THERE...THE CAMS MAY NOT BE ALL THAT RELIABLE FOR WHAT HAPPENS LATER THIS AFTERNOON AS ALL OF THEM ARE HANDLING CURRENT CONVECTION QUITE POORLY /INCLUDING ALL MEMBERS OF THE 3Z HOPWRF/. PROBLEM IS...OUTSIDE OF THE SPCWRF...NONE OF THE CAMS SNOW THUNDERSTORMS MOVING ACROSS THE AREA OUTLINED IN THE PARAGRAPH ABOVE...MANY /INCLUDING THE HOPWRF MEMBERS/ HAVE NOTHING MOVING ACROSS THE MPX AREA THIS MORNING...SO HARD TO PUT MUCH STOCK IN WHAT THEY ARE DOING THIS AFTERNOON. THE ONLY ONE TO BE SOMEWHAT CLOSE TO REALITY THIS MORNING /SPCWRF/...SHOWS VERY LITTLE CONVECTION REDEVELOPING IN THE MPX AREA THIS AFTERNOON. CERTAINLY A BIG PLUS FOR THE AFTERNOON...IS OVER THE LAST 24 HOURS...MODELS HAVE SLOWED UP THE PROGRESSION OF THE FRONT ACROSS THE MPX AREA...WHICH LIKELY EXPLAINS WHY HIGHER SEVERE PROBABILITIES WERE PULLED NORTHWEST WITH THE DAY1 SPC CONVECTIVE OUTLOOK. CURRENT MODEL BLEND WOULD SAY THE FRONT MOVES INTO THE NW MPX CWA AROUND 20Z...THE TWIN CITIES AROUND 00Z AND FINALLY CLEARS EAU AREA SHORTLY AFTER 3Z. THIS PUTS THE FRONT ACROSS MUCH OF THE AREA DURING PEAK HEATING...THOUGH IT IS STILL DEBATABLE HOW MUCH HEATING WE WILL SEE BEHIND THE MORNING CONVECTION. IF CURRENT FORECAST WERE TO HOLD...WITH TEMPERATURES REBOUNDING INTO THE MID 80S TO NEAR 90...WITH DEWPS IN THE LOWER 70S...THEN WE SHOULD HAVE NO PROBLEM GENERATING 2000-3500 J/KG OF MLCAPE AHEAD OF THE BOUNDARY AS THE NAM/GFS DO. FROM THE SHEAR PERSPECTIVE...A 40-60 KT MID LEVEL JET MOVING IN WITH THE UPPER WAVE THIS AFTERNOON/EVENING WILL PROVIDE PLENTY OF DEEP LAYER SHEAR TO SUPPORT UPDRAFT ROTATION AND STORM ORGANIZATION...BUT THE 0-3KM SHEAR IS LOOKING MORE SUSPECT ACROSS THE MPX AREA TO REALLY DRIVE UP A TORNADO THREAT. THE REASON FOR THE POOR LOW LEVEL SHEAR IS THAT THE PRESSURE PATTERN AHEAD OF THE FRONT WILL BE FAIRLY BAGGY...WITH LIGHT PREFRONTAL WINDS EXPECTED. IN ADDITION...THE CORE OF A 30-40 KT LLJ WILL EXTEND FROM CENTRAL IA TOWARD NE WIS...STAYING JUST SE OF THE MPX AREA. COMBINED...THE WEAK SFC WINDS AND BETTER LLJ BEING JUST SE OF THE MPX CWA RESULT IN MARGINAL 0-1 KM AND 0-3 KM SHEAR /MAINLY 20 KTS OR LESS/. BESIDE THE WEAKER SHEAR...THE WEAK SFC WINDS OUT AHEAD OF THE FRONT WILL ALSO LIMIT THE AMOUNT OF CONVERGENCE ALONG IT...WHICH MAY HELP EXPLAIN WHY MANY OF THE CAMS /OUTSIDE OF THE 3Z HOPWRF/ STRUGGLE TO GENERATE MUCH CONVECTION ALONG THE BOUNDARY THIS AFTERNOON. IN SUMMARY...CONFIDENCE IS HIGH THAT MCS CURRENTLY OVER ERN SODAK WILL TRACK ACROSS AREAS SOUTH OF I-94 THIS MORNING. BECAUSE OF THIS...CONFIDENCE IN HOW THE AFTERNOON PLAYS OUT IS CONSIDERABLY DIMINISHED. BUT...GIVEN FRONTAL TIMING...EXPECT AT LEAST SCT STORMS TO DEVELOP ALONG THE FRONT BETWEEN 19Z AND 21Z THAT WILL THEN TRACK SE THIS EVENING WITH THE FRONT. GIVEN DEGREE OF INSTABILITY AND BULK SHEAR...LARGE HAIL AND DAMAGING WINDS WILL BE THE PRIMARY THREAT. THE WEAKER LOW LEVEL SHEAR MEANS THAT UNLESS A STORM CAN LATCH ON TO A REMNANT OUTFLOW BOUNDARY...THE TORNADO THREAT APPEARS TO BE RELATIVELY LOW...THOUGH NOT NEGLIGIBLE. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 410 AM CDT TUE JUL 9 2013 THE FIRST HALF OF THE PERIOD WILL START OFF DRY AS LARGE SCALE SUBSIDENCE DOWNSTREAM OF THE UPPER LEVEL RIDGE AXIS BUILDS AN AREA OF SURFACE HIGH PRESSURE ACROSS THE UPPER MIDWEST. FORECAST SOUNDINGS SHOW A DRY PROFILE WITH PWATS ONLY AROUND 0.75 INCHES...ALONG WITH LITTLE POTENTIAL FOR CLOUDS DURING THE DAY ON WEDNESDAY. WINDS WILL GO CALM OVERNIGHT ALLOWING AN INVERSION TO SET UP AND TEMPERATURES TO COOL DOWN TO THE UPPER 50S ACROSS MOST LOCATIONS...WITH LOW 60S EXPECTED IN AND AROUND THE METRO DO TO THE HEAT ISLAND. THURSDAY WILL BE DRY AS WELL WITH THE SURFACE HIGH STILL SUPPRESSING ANY CHANCE OF PRECIP. BY THURSDAY NIGHT THE SURFACE HIGH WILL DRIFT EASTWARD AS THE THERMAL RIDGE APPROACHES FROM THE WEST...AND SOUTHERLY WINDS ON THE BACK SIDE WILL KEEP OVERNIGHT LOWS IN THE MID TO UPPER 60S ACROSS WESTERN MINNESOTA. FRIDAY SHOULD BE MUCH WARMER THAN CURRENTLY FORECAST BY THE NUMERICAL MODELS. BOTH THE GFS AND ECMWF 09.00 HAVE H850 TEMPS 20-22C...WITH SOUTHERLY WINDS OF 30KTS...YET FOR SOME REASON THE FORECAST SOUNDINGS ONLY SHOW MIXING UP TO AROUND 900MB. THIS IS CONTRADICTORY TO THE SIMPLE PROPERTIES THAT GOVERN THE ATMOSPHERE. GIVEN A MID JULY PROFILE THAT IS CLOUD FREE...TOGETHER WITH THE POTENTIAL FOR MECHANICAL MIXING...HAVE VERY HIGH CONFIDENCE THAT AFTERNOON TEMPERATURES WILL CLIMB INTO THE 90S ACROSS SOUTHWEST MINNESOTA. ON SATURDAY CONFIDENCE IN TEMPERATURES DECREASES CONSIDERABLY AS A FRONTAL BOUNDARY/TROUGH OF LOW PRESSURE STALLS OUT FROM SOUTHWEST TO NORTHEAST OVER THE UPPER MIDWEST. THIS WILL INTRODUCE CHANCES FOR SHOWERS AND THUNDERSTORMS...WHICH WILL GREATLY AFFECT AFTERNOON HIGHS. THEREFORE DID NOT STRAY TOO MUCH FROM BLENDED GUIDANCE...AND CONTINUE TO HAVE CHANCES FOR PRECIP INTO EARLY NEXT WEEK. THE BEST CHANCE FOR RAIN...WITH 1-3 INCH AMOUNTS VERY LIKELY AT A FEW LOCATIONS ACROSS THE NORTHWEST NEAR CANBY/ALEXANDRIA/ST CLOUD...WILL BE LATE FRIDAY NIGHT INTO SATURDAY MORNING. LOOKING AHEAD...THE THERMAL RIDGE WILL TAKE ON A POSITIVE TILT OVER THE UPPER MISSISSIPPI RIVER VALLEY. ON SUNDAY THE ECMWF DRIVES A SHORTWAVE ALONG THE US/CANADIAN BORDER THAT SUPPRESSES THE RIDGE...WHILE THE GFS IS A DAY SLOWER WITH THIS FEATURE. ALSO...AS ALLUDED TO EARLIER OVERCAST SKIES WILL GREATLY IMPACT HIGH TEMPS SO DID NOT HAVE THE CONFIDENCE TO DEVIATE FROM A CONSENSUS APPROACH. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING) ISSUED AT 700 AM CDT TUE JUL 9 2013 MATURE MCS WORKING ACROSS THE AIRSPACE THIS MORNING MOVING EAST AT ABOUT 35 KTS HAS BEEN TIMED THROUGH TAFS TO START OUT THIS MORNING. OTHER THAN A GUST TO 50 KTS AT RWF...ALL SITES TO THE WEST HAVE BEEN TOPPING OUT AT 40 KTS ON GUSTS. HARD TO SAY WHAT WILL HAPPEN THIS AFTERNOON AS THERE WILL BE A RECOVERY TIME FROM MORNING STORMS. HRRR SEEMS A BIT QUICK WITH THE FRONT...BUT SLOWING DOWN THE HRRR A BIT WOULD SUGGEST SCT TSRA POSSIBLE FROM RWF TO STC EAST AFTER 20Z...BUT CONFIDENCE LOW ON THAT HAPPENING NOW. WIND SPEEDS DO NOT PICK UP UNTIL YOU GET BEHIND THE FRONT AND SHOULD GUST TO 20-25 KTS BEHIND THE FRONT FOR A COUPLE OF HOURS. KMSP...TSRA STILL ON TARGET TO ARRIVE BETWEEN 1300 AND 1330Z AND OUT AROUND 1530. EXPECT BRIEF GUSTS UP AROUND 40 MPH OUT OF THE WEST...ALONG WITH BRIEF HEAVY DOWNPOURS. LOW CONFIDENCE ON WHAT HAPPENS THIS AFTERNOON...BUT THERE IS THE POTENTIAL FOR MORE TSRA BETWEEN 21Z AND 00Z BEFORE FRONT CLEARS EVERYTHING OUT AND ITS VFR THE REST OF THE WAY. /OUTLOOK FOR KMSP/ WED...VFR. WINDS NW 10G20KTS. THU...VFR. WINDS LGT AND VRB. FRI...VFR. WINDS S 10-15KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...MPG LONG TERM...JRB AVIATION...MPG
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1031 AM EDT TUE JUL 9 2013 .SYNOPSIS... UNSETTLED WEATHER WILL CONTINUE INTO THURSDAY, AS A SERIES OF DISTURBANCES COMBINE WITH A WARM MOIST AIRMASS OVER OUR AREA TO PRODUCE OCCASIONAL SHOWERS AND THUNDERSTORMS. DRIER AND COOLER AIR WILL FINALLY ARRIVE ON FRIDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 10 AM UPDATE... GRIDS IN GOOD SHAPE. SMALL ADJUSTMENTS MADE TO THE POPS BUT IN GENERAL IT LOOKED GOOD. SCATTERED SHOWER MOVING INTO STEUBEN NOW WILL INCREASE IN COVERAGE AND TSTORMS WILL JOIN THEM. SEVERE POTENTIAL MARGINAL BUT SOME SHOWERS AND TSTORMS WILL HAVE HEAVY RAIN. STORM MOTION ONLY SLIGHTLY BETTER THAN YESTERDAY AT 10 TO 15 MPH. TEMPS ADJUSTED UP IN THE SE WHERE SOME SUNSHINE HAS PUSHED TEMPS INTO THE U70S ALREADY. UPDATED AT 630 AM. JUST A FEW MINOR TWEAKS TO THE FORECAST TO ACCOUNT FOR THE LATEST TRENDS. HAVE ADDED PATCHY FOG TO SOUTHERN NY AND NORTHERN PA THROUGH 13Z. ALSO RADAR IS DETECTING A FEW SPRINKLES OR LIGHT SHOWERS OVER NORTHERN STEUBEN COUNTY. THESE SHOWERS ARE DIMINISHING AS THEY MOVE EAST AND ARE NOT EXPECTED TO REACH AS FAR EAST AS EVEN ELMIRA OR SYRACUSE THROUGH 9 AM. PREVIOUS DISCUSSION IS BELOW. LATEST WATER VAPOR LOOP SHOWS A BAND OF MOISTURE PROGRESSING EASTWARD ACROSS NY AND PA THIS MORNING WITH A SMALL AREA OF DRYING JUST TO THE WEST... THEN ANOTHER WAVE OF MOISTURE MOVING EAST ACROSS THE WESTERN GREAT LAKES. EXPECT EACH OF THESE FEATURES TO AFFECT OUR AREA THROUGH LATE THIS AFTERNOON. CLOUDS AND SCATTERED LIGHT SHOWERS WILL OVERSPREAD THE AREA THIS MORNING... THEN EXPECT SOME CLEARING BY AFTERNOON FOLLOWED BY A ROUND OF SCATTERED THUNDERSTORMS INTO THIS EVENING. MODELS ALL INDICATE MODEST SYNOPTIC SCALE FORCING FOR ASCENT MOVING ACROSS THE AREA THIS AFTERNOON IN THE FORM OF A SFC-700 MB TROUGH AND WEAK WAA. THIS SHOULD RESULT IN A SLIGHTLY GREATER COVERAGE OF STORMS THIS AFTERNOON WITH POPS INCREASING TO AROUND 50 PCT. LATEST RAP FORECAST SOUNDINGS INDICATE MLCAPE VALUES INCREASING TO BETWEEN 800 AND 1000 J/KG BY LATE THIS AFTERNOON. WIND PROFILES APPEAR TO BE RATHER LIGHT WTIH ONLY 10 TO 20 KTS OF WIND EXTENDING UP THROUGH 500 MB. MODEST FORCING AND INSTABILITY ALONG WITH WEAK WIND SHEAR SHOULD RESULT IN MOSTLY PULSE TYPE STORMS THIS AFTERNOON WITH NOTHING MORE THAN AN ISOLATED... MARGINAL SEVERE THREAT. ANY STORM COULD ALSO CONTAIN HEAVY DOWMPOURS ONCE AGAIN AS PWAT VALUES APPROACH 2.00 INCHES... ALTHOUGH THE SHEAR DOES NOT APPEAR TO BE STRONG ENOUGH TO SUPPORT ORGANIZED LONG-LASTING STORMS. && .SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/... SHOWERS AND THUNDERSTORMS WILL DECREASE IN COVERAGE THIS EVENING WITH LOSS OF HEATING AND PASSAGE OF THE TROUGH TO THE EAST OF THE AREA. ANOTHER ROUND OF SHOWERS AND STORMS APPEARS LIKELY ON WEDNESDAY AS A COLD FRONT APPROACHES FROM THE WEST ALONG WITH MID- LEVEL HEIGHT FALLS OF 30 TO 50 M ASSOCIATED WITH AN UPPER TROUGH MOVING EAST ACROSS SOUTHERN CANADA. EXPECT MLCAPE VALUES TO ONCE AGAIN REACH NEAR 1000 J/KG ACROSS THE AREA WEDNESDAY AFTERNOON... AND THIS WILL BE ACCOMPANIED BY DEEP LAYER SHEAR INCREASING TO 20 TO 30 KTS WITH THE APPROACH OF THE UPPER LEVEL TROUGH. THIS SCENARIO WOULD LEAD TO A GREATER CHANCE OF SEVERE WEATHER WEDNESDAY AFTERNOON WITH SOME LINEAR ORGANIZATION OF THE CONVECTION ALONG A PRE-FRONTAL TROUGH POSSIBLY RESULTING IN STRONG DAMAING WINDS. BASED ON THESE FACTORS THE SPC DAY 2 CONVECTIVE OUTLOOK INDICATES A SLIGHT RISK OF SEVERE STORMS WEDNESDAY AFTERNOON EXTENDING FROM THE OHIO VALLEY ACROSS NY AND PA. MODEL CONSENSUS INDICATES THAT THE COLD FRONT WILL BE MOVING EAST OF OUR AREA ON THURSDAY WITH THE BEST CHC OF SHOWERS AND STORMS THURSDAY AFTERNOON EXTENDING FROM EASTERN NY INTO NEW ENGLAND. STILL A CHC OF SHOWERS AND STORMS WILL EXIST IN OUR AREA ESPECIALLY EAST OF I-81. SLIGHTLY COOLER AND DRYER AIR WILL FOLLOW BEHIND THIS FRONT THURSDAY NIGHT INTO FRIDAY. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... 330 AM UPDATE...NO MAJOR CHANGES TO THE PREVIOUS FORECAST. STILL LOOKING LIKE WE MAY SEE AT LEAST A FEW DAYS OF DRY WEATHER STARTING FRIDAY...ESPECIALLY BASED ON THE NEW 0Z EURO. I DID MAINTAIN OUR GOING FORECAST OF SLIGHT TO LOW CHANCE (20 TO 30%) POPS THIS WEEKEND WITH THE GFS HINTING AT A DISTURBANCE ALOFT IN THE NORTHEAST DURING THIS TIME. THIS ALSO MATCHES UP WITH POP GUIDANCE FROM WPC. WITH THAT SAID BASED ON THE EURO AND SURFACE HIGH PRESSURE BUILDING IN...THE REALITY MAY BE A DRY WEEKEND. THE PREVIOUS AFD IS BELOW... STAGNANT PTRN CONTS TO MAKE FOR A TRICKY XTNDD PD. LATEST OPERATIONAL GFS RUN TRENDS TWRDS LAST NGT/S EURO WITH THU/S BRIEF RDGG GIVING WAY TO YET ANOTHER RETROGRADING OFF SHORE TROF. MASSIVE BERMUDA HI CONTS TO BLOCK THE EWRD PROGRESS OF NRN STREAM WV/S KEEPING THE NORTH BOUND TROPICAL FLOW IN PLACE ALONG THE CST NEAR TO OUR FCST AREA. FOR NOW...IT LOOKS LIKE THE MAJORITY OF THE MOISTURE ASSOCIATED WITH CHANTAL WELL EAST OF THE AREA...BUT WITH THE UNCERTAINTY...THIS DEEP MOISTURE WILL NEED TO BE MONITORED. DAILY SENSIBLE WX WILL SHOW SOME IMPRMNT ALTHOUGH THE ERN AND SRN AREA WILL CONT TO BE NEAR THE EDGE OF THE DEEP MOISTURE AND MORE AT RISK OF TRWS...ESP LATE IN THE PD. GNRLY FLWD HPC GUID BUT NUDGED THE DATA TWRD THE MEX AND NEARER TO THE SURROUNDING OFFICES. && .AVIATION /15Z TUESDAY THROUGH SATURDAY/... 12Z UPDATE... IFR RESTRICTIONS LIKELY TO CONTINUE IN DENSE FOG AT KBGM AND KELM THROUGH ABOUT 13Z BEFORE IMPROVEMENT TO VFR. ELSEWHERE MAINLY VFR TODAY OVERALL. SCT SHOWERS WITH SOME THUNDER POSSIBLE ESPECIALLY BETWEEN 18Z AND 0Z. SOME BRIEF MVFR OR IFR RESTRICTIONS DUE TO HEAVY RAIN (VSBY) POSSIBLE. AT THIS POINT TOO UNCERTAIN TO INCLUDE IN THE TAFS BUT AS WE GET CLOSER...SOME SHORT TERM TEMPOS MAY BE NEEDED. .OUTLOOK... WED THRU THU...PRIMARILY VFR BUT WITH RESTRICTIONS IN SCT SHWRS AND TRWS. IFR WITH OVRNGT VLY FOG PSBL. FRI/SAT...VFR WITH BRIEF IFR IN VLY FOG. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...MSE/TAC NEAR TERM...MSE/TAC SHORT TERM...MSE LONG TERM...DGM/HEDEN AVIATION...HEDEN
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
817 AM EDT TUE JUL 9 2013 .SYNOPSIS... UNSETTLED WEATHER WILL CONTINUE INTO THURSDAY, AS A SERIES OF DISTURBANCES COMBINE WITH A WARM MOIST AIRMASS OVER OUR AREA TO PRODUCE OCCASIONAL SHOWERS AND THUNDERSTORMS. DRIER AND COOLER AIR WILL FINALLY ARRIVE ON FRIDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... UPDATED AT 630 AM. JUST A FEW MINOR TWEAKS TO THE FORECAST TO ACCOUNT FOR THE LATEST TRENDS. HAVE ADDED PATCHY FOG TO SOUTHERN NY AND NORTHERN PA THROUGH 13Z. ALSO RADAR IS DETECTING A FEW SPRINKLES OR LIGHT SHOWERS OVER NORTHERN STEUBEN COUNTY. THESE SHOWERS ARE DIMINISHING AS THEY MOVE EAST AND ARE NOT EXPECTED TO REACH AS FAR EAST AS EVEN ELMIRA OR SYRACUSE THROUGH 9 AM. PREVIOUS DISCUSSION IS BELOW. LATEST WATER VAPOR LOOP SHOWS A BAND OF MOISTURE PROGRESSING EASTWARD ACROSS NY AND PA THIS MORNING WITH A SMALL AREA OF DRYING JUST TO THE WEST... THEN ANOTHER WAVE OF MOISTURE MOVING EAST ACROSS THE WESTERN GREAT LAKES. EXPECT EACH OF THESE FEATURES TO AFFECT OUR AREA THROUGH LATE THIS AFTERNOON. CLOUDS AND SCATTERED LIGHT SHOWERS WILL OVERSPREAD THE AREA THIS MORNING... THEN EXPECT SOME CLEARING BY AFTERNOON FOLLOWED BY A ROUND OF SCATTERED THUNDERSTORMS INTO THIS EVENING. MODELS ALL INDICATE MODEST SYNOPTIC SCALE FORCING FOR ASCENT MOVING ACROSS THE AREA THIS AFTERNOON IN THE FORM OF A SFC-700 MB TROUGH AND WEAK WAA. THIS SHOULD RESULT IN A SLIGHTLY GREATER COVERAGE OF STORMS THIS AFTERNOON WITH POPS INCREASING TO AROUND 50 PCT. LATEST RAP FORECAST SOUNDINGS INDICATE MLCAPE VALUES INCREASING TO BETWEEN 800 AND 1000 J/KG BY LATE THIS AFTERNOON. WIND PROFILES APPEAR TO BE RATHER LIGHT WTIH ONLY 10 TO 20 KTS OF WIND EXTENDING UP THROUGH 500 MB. MODEST FORCING AND INSTABILITY ALONG WITH WEAK WIND SHEAR SHOULD RESULT IN MOSTLY PULSE TYPE STORMS THIS AFTERNOON WITH NOTHING MORE THAN AN ISOLATED... MARGINAL SEVERE THREAT. ANY STORM COULD ALSO CONTAIN HEAVY DOWMPOURS ONCE AGAIN AS PWAT VALUES APPROACH 2.00 INCHES... ALTHOUGH THE SHEAR DOES NOT APPEAR TO BE STRONG ENOUGH TO SUPPORT ORGANIZED LONG-LASTING STORMS. && .SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/... SHOWERS AND THUNDERSTORMS WILL DECREASE IN COVERAGE THIS EVENING WITH LOSS OF HEATING AND PASSAGE OF THE TROUGH TO THE EAST OF THE AREA. ANOTHER ROUND OF SHOWERS AND STORMS APPEARS LIKELY ON WEDNESDAY AS A COLD FRONT APPROACHES FROM THE WEST ALONG WITH MID- LEVEL HEIGHT FALLS OF 30 TO 50 M ASSOCIATED WITH AN UPPER TROUGH MOVING EAST ACROSS SOUTHERN CANADA. EXPECT MLCAPE VALUES TO ONCE AGAIN REACH NEAR 1000 J/KG ACROSS THE AREA WEDNESDAY AFTERNOON... AND THIS WILL BE ACCOMPANIED BY DEEP LAYER SHEAR INCREASING TO 20 TO 30 KTS WITH THE APPROACH OF THE UPPER LEVEL TROUGH. THIS SCENARIO WOULD LEAD TO A GREATER CHANCE OF SEVERE WEATHER WEDNESDAY AFTERNOON WITH SOME LINEAR ORGANIZATION OF THE CONVECTION ALONG A PRE-FRONTAL TROUGH POSSIBLY RESULTING IN STRONG DAMAING WINDS. BASED ON THESE FACTORS THE SPC DAY 2 CONVECTIVE OUTLOOK INDICATES A SLIGHT RISK OF SEVERE STORMS WEDNESDAY AFTERNOON EXTENDING FROM THE OHIO VALLEY ACROSS NY AND PA. MODEL CONSENSUS INDICATES THAT THE COLD FRONT WILL BE MOVING EAST OF OUR AREA ON THURSDAY WITH THE BEST CHC OF SHOWERS AND STORMS THURSDAY AFTERNOON EXTENDING FROM EASTERN NY INTO NEW ENGLAND. STILL A CHC OF SHOWERS AND STORMS WILL EXIST IN OUR AREA ESPECIALLY EAST OF I-81. SLIGHTLY COOLER AND DRYER AIR WILL FOLLOW BEHIND THIS FRONT THURSDAY NIGHT INTO FRIDAY. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... 330 AM UPDATE...NO MAJOR CHANGES TO THE PREVIOUS FORECAST. STILL LOOKING LIKE WE MAY SEE AT LEAST A FEW DAYS OF DRY WEATHER STARTING FRIDAY...ESPECIALLY BASED ON THE NEW 0Z EURO. I DID MAINTAIN OUR GOING FORECAST OF SLIGHT TO LOW CHANCE (20 TO 30%) POPS THIS WEEKEND WITH THE GFS HINTING AT A DISTURBANCE ALOFT IN THE NORTHEAST DURING THIS TIME. THIS ALSO MATCHES UP WITH POP GUIDANCE FROM WPC. WITH THAT SAID BASED ON THE EURO AND SURFACE HIGH PRESSURE BUILDING IN...THE REALITY MAY BE A DRY WEEKEND. THE PREVIOUS AFD IS BELOW... STAGNANT PTRN CONTS TO MAKE FOR A TRICKY XTNDD PD. LATEST OPERATIONAL GFS RUN TRENDS TWRDS LAST NGT/S EURO WITH THU/S BRIEF RDGG GIVING WAY TO YET ANOTHER RETROGRADING OFF SHORE TROF. MASSIVE BERMUDA HI CONTS TO BLOCK THE EWRD PROGRESS OF NRN STREAM WV/S KEEPING THE NORTH BOUND TROPICAL FLOW IN PLACE ALONG THE CST NEAR TO OUR FCST AREA. FOR NOW...IT LOOKS LIKE THE MAJORITY OF THE MOISTURE ASSOCIATED WITH CHANTAL WELL EAST OF THE AREA...BUT WITH THE UNCERTAINTY...THIS DEEP MOISTURE WILL NEED TO BE MONITORED. DAILY SENSIBLE WX WILL SHOW SOME IMPRMNT ALTHOUGH THE ERN AND SRN AREA WILL CONT TO BE NEAR THE EDGE OF THE DEEP MOISTURE AND MORE AT RISK OF TRWS...ESP LATE IN THE PD. GNRLY FLWD HPC GUID BUT NUDGED THE DATA TWRD THE MEX AND NEARER TO THE SURROUNDING OFFICES. && .AVIATION /12Z TUESDAY THROUGH SATURDAY/... 12Z UPDATE... IFR RESTRICTIONS LIKELY TO CONTINUE IN DENSE FOG AT KBGM AND KELM THROUGH ABOUT 13Z BEFORE IMPROVEMENT TO VFR. ELSEWHERE MAINLY VFR TODAY OVERALL. SCT SHOWERS WITH SOME THUNDER POSSIBLE ESPECIALLY BETWEEN 18Z AND 0Z. SOME BRIEF MVFR OR IFR RESTRICTIONS DUE TO HEAVY RAIN (VSBY) POSSIBLE. AT THIS POINT TOO UNCERTAIN TO INCLUDE IN THE TAFS BUT AS WE GET CLOSER...SOME SHORT TERM TEMPOS MAY BE NEEDED. .OUTLOOK... WED THRU THU...PRIMARILY VFR BUT WITH RESTRICTIONS IN SCT SHWRS AND TRWS. IFR WITH OVRNGT VLY FOG PSBL. FRI/SAT...VFR WITH BRIEF IFR IN VLY FOG. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...MSE/TAC NEAR TERM...MSE SHORT TERM...MSE LONG TERM...DGM/HEDEN AVIATION...HEDEN
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
701 AM EDT TUE JUL 9 2013 .SYNOPSIS... UNSETTLED WEATHER WILL CONTINUE INTO THURSDAY AS A SERIES OF DISTURBANCES COMBINE WITH A WARM MOIST AIRMASS OVER OUR AREA TO PRODUCE OCCASIONAL SHOWERS AND THUNDERSTORMS. DRYER AIR WILL FINALLY ARRIVE ON FRIDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... UPDATED AT 630 AM. JUST A FEW MINOR TWEAKS TO THE FORECAST TO ACCOUNT FOR THE LATEST TRENDS. HAVE ADDED PATCHY FOG TO SOUTHERN NY AND NORTHERN PA THROUGH 13Z. ALSO RADAR IS DETECTING A FEW SPRINKLES OR LIGHT SHOWERS OVER NORTHERN STEUBEN COUNTY. THESE SHOWERS ARE DIMINISHING AS THEY MOVE EAST AND ARE NOT EXPECTED TO REACH AS FAR EAST AS EVEN ELMIRA OR SYRACUSE THROUGH 9 AM. PREVIOUS DISCUSSION IS BELOW. LATEST WATER VAPOR LOOP SHOWS A BAND OF MOISTURE PROGRESSING EASTWARD ACROSS NY AND PA THIS MORNING WITH A SMALL AREA OF DRYING JUST TO THE WEST... THEN ANOTHER WAVE OF MOISTURE MOVING EAST ACROSS THE WESTERN GREAT LAKES. EXPECT EACH OF THESE FEATURES TO AFFECT OUR AREA THROUGH LATE THIS AFTERNOON. CLOUDS AND SCATTERED LIGHT SHOWERS WILL OVERSPREAD THE AREA THIS MORNING... THEN EXPECT SOME CLEARING BY AFTERNOON FOLLOWED BY A ROUND OF SCATTERED THUNDERSTORMS INTO THIS EVENING. MODELS ALL INDICATE MODEST SYNOPTIC SCALE FORCING FOR ASCENT MOVING ACROSS THE AREA THIS AFTERNOON IN THE FORM OF A SFC-700 MB TROUGH AND WEAK WAA. THIS SHOULD RESULT IN A SLIGHTLY GREATER COVERAGE OF STORMS THIS AFTERNOON WITH POPS INCREASING TO AROUND 50 PCT. LATEST RAP FORECAST SOUNDINGS INDICATE MLCAPE VALUES INCREASING TO BETWEEN 800 AND 1000 J/KG BY LATE THIS AFTERNOON. WIND PROFILES APPEAR TO BE RATHER LIGHT WTIH ONLY 10 TO 20 KTS OF WIND EXTENDING UP THROUGH 500 MB. MODEST FORCING AND INSTABILITY ALONG WITH WEAK WIND SHEAR SHOULD RESULT IN MOSTLY PULSE TYPE STORMS THIS AFTERNOON WITH NOTHING MORE THAN AN ISOLATED... MARGINAL SEVERE THREAT. ANY STORM COULD ALSO CONTAIN HEAVY DOWMPOURS ONCE AGAIN AS PWAT VALUES APPROACH 2.00 INCHES... ALTHOUGH THE SHEAR DOES NOT APPEAR TO BE STRONG ENOUGH TO SUPPORT ORGANIZED LONG-LASTING STORMS. && .SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/... SHOWERS AND THUNDERSTORMS WILL DECREASE IN COVERAGE THIS EVENING WITH LOSS OF HEATING AND PASSAGE OF THE TROUGH TO THE EAST OF THE AREA. ANOTHER ROUND OF SHOWERS AND STORMS APPEARS LIKELY ON WEDNESDAY AS A COLD FRONT APPROACHES FROM THE WEST ALONG WITH MID- LEVEL HEIGHT FALLS OF 30 TO 50 M ASSOCIATED WITH AN UPPER TROUGH MOVING EAST ACROSS SOUTHERN CANADA. EXPECT MLCAPE VALUES TO ONCE AGAIN REACH NEAR 1000 J/KG ACROSS THE AREA WEDNESDAY AFTERNOON... AND THIS WILL BE ACCOMPANIED BY DEEP LAYER SHEAR INCREASING TO 20 TO 30 KTS WITH THE APPROACH OF THE UPPER LEVEL TROUGH. THIS SCENARIO WOULD LEAD TO A GREATER CHANCE OF SEVERE WEATHER WEDNESDAY AFTERNOON WITH SOME LINEAR ORGANIZATION OF THE CONVECTION ALONG A PRE-FRONTAL TROUGH POSSIBLY RESULTING IN STRONG DAMAING WINDS. BASED ON THESE FACTORS THE SPC DAY 2 CONVECTIVE OUTLOOK INDICATES A SLIGHT RISK OF SEVERE STORMS WEDNESDAY AFTERNOON EXTENDING FROM THE OHIO VALLEY ACROSS NY AND PA. MODEL CONSENSUS INDICATES THAT THE COLD FRONT WILL BE MOVING EAST OF OUR AREA ON THURSDAY WITH THE BEST CHC OF SHOWERS AND STORMS THURSDAY AFTERNOON EXTENDING FROM EASTERN NY INTO NEW ENGLAND. STILL A CHC OF SHOWERS AND STORMS WILL EXIST IN OUR AREA ESPECIALLY EAST OF I-81. SLIGHTLY COOLER AND DRYER AIR WILL FOLLOW BEHIND THIS FRONT THURSDAY NIGHT INTO FRIDAY. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... 330 AM UPDATE...NO MAJOR CHANGES TO THE PREVIOUS FORECAST. STILL LOOKING LIKE WE MAY SEE AT LEAST A FEW DAYS OF DRY WEATHER STARTING FRIDAY...ESPECIALLY BASED ON THE NEW 0Z EURO. I DID MAINTAIN OUR GOING FORECAST OF SLIGHT TO LOW CHANCE (20 TO 30%) POPS THIS WEEKEND WITH THE GFS HINTING AT A DISTURBANCE ALOFT IN THE NORTHEAST DURING THIS TIME. THIS ALSO MATCHES UP WITH POP GUIDANCE FROM WPC. WITH THAT SAID BASED ON THE EURO AND SURFACE HIGH PRESSURE BUILDING IN...THE REALITY MAY BE A DRY WEEKEND. THE PREVIOUS AFD IS BELOW... STAGNANT PTRN CONTS TO MAKE FOR A TRICKY XTNDD PD. LATEST OPERATIONAL GFS RUN TRENDS TWRDS LAST NGT/S EURO WITH THU/S BRIEF RDGG GIVING WAY TO YET ANOTHER RETROGRADING OFF SHORE TROF. MASSIVE BERMUDA HI CONTS TO BLOCK THE EWRD PROGRESS OF NRN STREAM WV/S KEEPING THE NORTH BOUND TROPICAL FLOW IN PLACE ALONG THE CST NEAR TO OUR FCST AREA. FOR NOW...IT LOOKS LIKE THE MAJORITY OF THE MOISTURE ASSOCIATED WITH CHANTAL WELL EAST OF THE AREA...BUT WITH THE UNCERTAINTY...THIS DEEP MOISTURE WILL NEED TO BE MONITORED. DAILY SENSIBLE WX WILL SHOW SOME IMPRMNT ALTHOUGH THE ERN AND SRN AREA WILL CONT TO BE NEAR THE EDGE OF THE DEEP MOISTURE AND MORE AT RISK OF TRWS...ESP LATE IN THE PD. GNRLY FLWD HPC GUID BUT NUDGED THE DATA TWRD THE MEX AND NEARER TO THE SURROUNDING OFFICES. && .AVIATION /12Z TUESDAY THROUGH SATURDAY/... 12Z UPDATE... IFR RESTRICTIONS LIKELY TO CONTINUE IN DENSE FOG AT KBGM AND KELM THROUGH ABOUT 13Z BEFORE IMPROVEMENT TO VFR. ELSEWHERE MAINLY VFR TODAY OVERALL. SCT SHOWERS WITH SOME THUNDER POSSIBLE ESPECIALLY BETWEEN 18Z AND 0Z. SOME BRIEF MVFR OR IFR RESTRICTIONS DUE TO HEAVY RAIN (VSBY) POSSIBLE. AT THIS POINT TOO UNCERTAIN TO INCLUDE IN THE TAFS BUT AS WE GET CLOSER...SOME SHORT TERM TEMPOS MAY BE NEEDED. .OUTLOOK... WED THRU THU...PRIMARILY VFR BUT WITH RESTRICTIONS IN SCT SHWRS AND TRWS. IFR WITH OVRNGT VLY FOG PSBL. FRI/SAT...VFR WITH BRIEF IFR IN VLY FOG. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...MSE NEAR TERM...MSE SHORT TERM...MSE LONG TERM...DGM/HEDEN AVIATION...HEDEN
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
633 AM EDT TUE JUL 9 2013 .SYNOPSIS... UNSETTLED WEATHER WILL CONTINUE INTO THURSDAY AS A SERIES OF DISTURBANCES COMBINE WITH A WARM MOIST AIRMASS OVER OUR AREA TO PRODUCE OCCASIONAL SHOWERS AND THUNDERSTORMS. DRYER AIR WILL FINALLY ARRIVE ON FRIDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... UPDATED AT 630 AM. JUST A FEW MINOR TWEAKS TO THE FORECAST TO ACCOUNT FOR THE LATEST TRENDS. HAVE ADDED PATCHY FOG TO SOUTHERN NY AND NORTHERN PA THROUGH 13Z. ALSO RADAR IS DETECTING A FEW SPRINKLES OR LIGHT SHOWERS OVER NORTHERN STEUBEN COUNTY. THESE SHOWERS ARE DIMINISHING AS THEY MOVE EAST AND ARE NOT EXPECTED TO REACH AS FAR EAST AS EVEN ELMIRA OR SYRACUSE THROUGH 9 AM. PREVIOUS DISCUSSION IS BELOW. LATEST WATER VAPOR LOOP SHOWS A BAND OF MOISTURE PROGRESSING EASTWARD ACROSS NY AND PA THIS MORNING WITH A SMALL AREA OF DRYING JUST TO THE WEST... THEN ANOTHER WAVE OF MOISTURE MOVING EAST ACROSS THE WESTERN GREAT LAKES. EXPECT EACH OF THESE FEATURES TO AFFECT OUR AREA THROUGH LATE THIS AFTERNOON. CLOUDS AND SCATTERED LIGHT SHOWERS WILL OVERSPREAD THE AREA THIS MORNING... THEN EXPECT SOME CLEARING BY AFTERNOON FOLLOWED BY A ROUND OF SCATTERED THUNDERSTORMS INTO THIS EVENING. MODELS ALL INDICATE MODEST SYNOPTIC SCALE FORCING FOR ASCENT MOVING ACROSS THE AREA THIS AFTERNOON IN THE FORM OF A SFC-700 MB TROUGH AND WEAK WAA. THIS SHOULD RESULT IN A SLIGHTLY GREATER COVERAGE OF STORMS THIS AFTERNOON WITH POPS INCREASING TO AROUND 50 PCT. LATEST RAP FORECAST SOUNDINGS INDICATE MLCAPE VALUES INCREASING TO BETWEEN 800 AND 1000 J/KG BY LATE THIS AFTERNOON. WIND PROFILES APPEAR TO BE RATHER LIGHT WTIH ONLY 10 TO 20 KTS OF WIND EXTENDING UP THROUGH 500 MB. MODEST FORCING AND INSTABILITY ALONG WITH WEAK WIND SHEAR SHOULD RESULT IN MOSTLY PULSE TYPE STORMS THIS AFTERNOON WITH NOTHING MORE THAN AN ISOLATED... MARGINAL SEVERE THREAT. ANY STORM COULD ALSO CONTAIN HEAVY DOWMPOURS ONCE AGAIN AS PWAT VALUES APPROACH 2.00 INCHES... ALTHOUGH THE SHEAR DOES NOT APPEAR TO BE STRONG ENOUGH TO SUPPORT ORGANIZED LONG-LASTING STORMS. && .SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/... SHOWERS AND THUNDERSTORMS WILL DECREASE IN COVERAGE THIS EVENING WITH LOSS OF HEATING AND PASSAGE OF THE TROUGH TO THE EAST OF THE AREA. ANOTHER ROUND OF SHOWERS AND STORMS APPEARS LIKELY ON WEDNESDAY AS A COLD FRONT APPROACHES FROM THE WEST ALONG WITH MID- LEVEL HEIGHT FALLS OF 30 TO 50 M ASSOCIATED WITH AN UPPER TROUGH MOVING EAST ACROSS SOUTHERN CANADA. EXPECT MLCAPE VALUES TO ONCE AGAIN REACH NEAR 1000 J/KG ACROSS THE AREA WEDNESDAY AFTERNOON... AND THIS WILL BE ACCOMPANIED BY DEEP LAYER SHEAR INCREASING TO 20 TO 30 KTS WITH THE APPROACH OF THE UPPER LEVEL TROUGH. THIS SCENARIO WOULD LEAD TO A GREATER CHANCE OF SEVERE WEATHER WEDNESDAY AFTERNOON WITH SOME LINEAR ORGANIZATION OF THE CONVECTION ALONG A PRE-FRONTAL TROUGH POSSIBLY RESULTING IN STRONG DAMAING WINDS. BASED ON THESE FACTORS THE SPC DAY 2 CONVECTIVE OUTLOOK INDICATES A SLIGHT RISK OF SEVERE STORMS WEDNESDAY AFTERNOON EXTENDING FROM THE OHIO VALLEY ACROSS NY AND PA. MODEL CONSENSUS INDICATES THAT THE COLD FRONT WILL BE MOVING EAST OF OUR AREA ON THURSDAY WITH THE BEST CHC OF SHOWERS AND STORMS THURSDAY AFTERNOON EXTENDING FROM EASTERN NY INTO NEW ENGLAND. STILL A CHC OF SHOWERS AND STORMS WILL EXIST IN OUR AREA EXPECIALLY EAST OF I-81. SLIGHTLY COOLER AND DRYER AIR WILL FOLLOW BEHIND THIS FRONT THURSDAY NIGHT INTO FRIDAY. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... 330 AM UPDATE...NO MAJOR CHANGES TO THE PREVIOUS FORECAST. STILL LOOKING LIKE WE MAY SEE AT LEAST A FEW DAYS OF DRY WEATHER STARTING FRIDAY...ESPECIALLY BASED ON THE NEW 0Z EURO. I DID MAINTAIN OUR GOING FORECAST OF SLIGHT TO LOW CHANCE (20 TO 30%) POPS THIS WEEKEND WITH THE GFS HINTING AT A DISTURBANCE ALOFT IN THE NORTHEAST DURING THIS TIME. THIS ALSO MATCHES UP WITH POP GUIDANCE FROM WPC. WITH THAT SAID BASED ON THE EURO AND SURFACE HIGH PRESSURE BUILDING IN...THE REALITY MAY BE A DRY WEEKEND. THE PREVIOUS AFD IS BELOW... STAGNANT PTRN CONTS TO MAKE FOR A TRICKY XTNDD PD. LATEST OPERATIONAL GFS RUN TRENDS TWRDS LAST NGT/S EURO WITH THU/S BRIEF RDGG GIVING WAY TO YET ANOTHER RETROGRADING OFF SHORE TROF. MASSIVE BERMUDA HI CONTS TO BLOCK THE EWRD PROGRESS OF NRN STREAM WV/S KEEPING THE NORTH BOUND TROPICAL FLOW IN PLACE ALONG THE CST NEAR TO OUR FCST AREA. FOR NOW...IT LOOKS LIKE THE MAJORITY OF THE MOISTURE ASSOCIATED WITH CHANTAL WELL EAST OF THE AREA...BUT WITH THE UNCERTAINTY...THIS DEEP MOISTURE WILL NEED TO BE MONITORED. DAILY SENSIBLE WX WILL SHOW SOME IMPRMNT ALTHOUGH THE ERN AND SRN AREA WILL CONT TO BE NEAR THE EDGE OF THE DEEP MOISTURE AND MORE AT RISK OF TRWS...ESP LATE IN THE PD. GNRLY FLWD HPC GUID BUT NUDGED THE DATA TWRD THE MEX AND NEARER TO THE SURROUNDING OFFICES. && .AVIATION /12Z TUESDAY THROUGH SATURDAY/... 06Z UPDATE... PERIODS OF FOG...PRODUCING IFR RESTRICTIONS ARE POSSIBLE THROUGH DAYBREAK ESPECIALLY AT KELM/KITH/KBGM WITH THESE SITES SEEING THE MOST RAIN MONDAY AFTERNOON. A COMPLICATING FACTOR WILL BE AN AREA OF HIGH CLOUDS NOW OVER WESTERN NY THAT WILL SLIDE EAST DURING THIS PERIOD. WITH IFR RESTRICTIONS ALREADY AT ALL THREE SITES BEING TEMPERED BY THIS HIGH CLOUD THREAT...ELECTED TO MAINLY GO WITH TEMPO GROUPS FOR IFR GIVEN THE HIGH VARIABILITY EXPECTED THROUGHOUT THE NIGHT. KELM STANDS THE BEST CHANCE FOR GOING DOWN AND STAYING DOWN. ELSEWHERE VFR IS EXPECTED. ANY FOG SHOULD BURN OFF BETWEEN 12Z AND 13Z. AFTER THAT A DISTURBANCE MOVING THROUGH LATER IN THE DAY WILL BRING SCT. SHOWERS TO THE TERMINALS MAINLY DURING THE PEAK HEATING (18Z - 0Z). WHILE THUNDER IS POSSIBLE I DID NOT INCLUDE IN THE TAFS JUST YET GIVEN THE EXPECTED SCT. COVERAGE. .OUTLOOK... WED THRU THU...PRIMARILY VFR BUT WITH RESTRICTIONS IN SCT SHWRS AND TRWS. IFR WITH OVRNGT VLY FOG PSBL. FRI/SAT...VFR WITH BRIEF IFR IN VLY FOG. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...MSE NEAR TERM...MSE SHORT TERM...MSE LONG TERM...DGM/HEDEN AVIATION...HEDEN
AREA FORECAST DISCUSSION
NWS RALEIGH NC
940 AM EDT TUE JUL 9 2013 .SYNOPSIS... A WEAK UPPER LEVEL LOW PRESSURE TROUGH WILL HOLD OVER THE EASTERN U.S. THROUGH WEDNESDAY. A STRONGER UPPER LEVEL TROUGH AND ASSOCIATED SURFACE COLD FRONT WILL APPROACH THE AREA FROM THE NORTHEAST LATE WEDNESDAY... AND SWING THROUGH THE REGION THURSDAY THROUGH FRIDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 940 AM TUESDAY... REST OF TODAY THROUGH TONIGHT: QUITE A BIT OF STRATUS (ABOUT 500 FT THICK ACCORDING TO PILOT REPORTS) IS HOLDING OVER THE AREA... PARTICULARY NRN/WRN AREAS. WATER VAPOR IMAGERY SHOWS A SUBTLE VORTICITY MAX DROPPING THROUGH CENTRAL VA INTO NRN NC... ON THE HEELS OF ANOTHER WAVE NOW SUPPORTING SLOW-MOVING THUNDERSTORM CLUSTERS NEAR THE COAST. THE LATEST HRRR RUNS SHOW SCATTERED TO NUMEROUS STORMS DEVELOPING OVER THE SRN/ERN PORTIONS OF THE FORECAST AREA... PERHAPS A RESPONSE TO BOTH GREATER HEATING IN THIS AREA THIS MORNING AND THE PASSAGE OF THIS WEAK WAVE. CURRENT FORECAST... WITH MINOR ADJUSTMENTS IN TIMING AND AREA... HINTS AT THIS SCENARIO AND LOOKS VERY REASONABLE GIVEN THE SHORT TERM TRENDS. CINH IS QUICKLY ERODING WITH MLCAPE ALREADY AT 1500 J/KG... BUT WITH LOW DEEP-LAYER BULK SHEAR AND MEANDERING MOVEMENT... STORMS SHOULD STAY BELOW SEVERE LIMITS... BUT THE RISK OF LOCALLY HEAVY DOWNPOURS WILL PERSIST. LOW LEVEL THICKNESSES FAVOR HIGHS IN THE UPPER 80S... IN LINE WITH LATEST STATISTICAL GUIDANCE AND EXISTING FORECAST... FACTORING IN VARIABLY CLOUDY SKIES. -GIH THOUGH COVERAGE AND INTENSITY SHOULD DIMINISH WITH NOCTURNAL COOLING...THE VERY MOIST AND WEAKLY CONDITIONALLY UNSTABLE AIR MASS OVERNIGHT WILL LIKELY SUPPORT A FEW SHOWERS. LOWS IN THE LOWER 70S. -MWS && .SHORT TERM /WEDNESDAY AND WEDNESDAY NIGHT/... AS OF 315 AM TUESDAY... WEDNESDAY AND WEDNESDAY NIGHT: PERSISTENCE OVERALL...WITH CONTINUED BERMUDA HIGH PRESSURE EXTENDING WESTWARD INTO THE CAROLINAS... BENEATH TROUGHING/CYCLONIC FLOW IN THE MID LEVELS. THIS PATTERN...AMIDST A VERY MOIST AND UNCAPPED BOUNDARY LAYER...SHOULD AGAIN PRODUCE SCATTERED SHOWERS AND STORMS MAXIMIZED WITH DIURNAL HEATING. IN ADDITION...GULF MOISTURE...WHICH WILL HAVE BEEN PREVIOUSLY LIMITED OWING TO RIDGING OVER THE GOM AND GULF COAST STATES...WILL HAVE CIRCUMVENTED THE RIDGE AND ARRIVE IN STRENGTHENING H85 WESTERLY FLOW LATE WED AND ESPECIALLY WED NIGHT. THIS REGIME...AS WELL AS INCREASING HEIGHT FALLS ALOFT DOWNSTREAM OF A POWERFUL TROUGH AMPLIFYING THROUGH THE GREAT LAKES...MAY SUPPORT ADDITIONAL CONVECTION OVERNIGHT...MAINLY OVER THE WESTERN PIEDMONT WHERE THE EFFECTS OF THE MOISTURE TRANSPORT/ISENTROPIC UPGLIDE WILL OCCUR FIRST. PERSISTENCE TEMPS IN THE UPPER 80S TO AROUND 90...AND LOWER 70S. && .LONG TERM /THURSDAY THROUGH MONDAY/... AS OF 225 AM TUESDAY... THURSDAY THROUGH FRIDAY IS EXPECTED TO BE A WET PERIOD ONCE AGAIN. THE APPROACH OF ANOTHER MID/UPPER TROUGH FROM THE NW COMBINED WITH THE SURFACE COLD FRONT SETTLING INTO LOWER TO MID 70S DEW POINTS WILL SET THE STAGE FOR YET ANOTHER COUPLE OF DAYS WITH WIDESPREAD CONVECTIVE RAINS. THE HIGHEST POP IS EXPECTED ON THURSDAY OVER THE PIEDMONT INTO PORTIONS OF THE COASTAL PLAIN AND SANDHILLS BY LATE AFTERNOON/EVENING. CONVECTIVE DEVELOPMENT THURSDAY SHOULD BE AIDED BY THE LEE TROUGH AND DIFFERENTIAL HEATING ALONG THE MOUNTAINS. THE FORMER SHOULD RESULT IN GOOD LOW LEVEL CONVERGENCE WITH PRECIPITABLE WATER VALUES INCREASING TO BETWEEN 1.8 AND 2 INCHES FAVORING HEAVY RAINERS SPREADING OFF THE BLUE RIDGE OUT OVER THE PIEDMONT BY EARLY AFTERNOON. ADDITIONAL DEVELOPMENT SHOULD OCCUR ALONG THE LEE TROUGH AND NUMEROUS CONVECTIVE OUTFLOWS DURING THE MID TO LATE AFTERNOON EASTWARD THROUGH THE PIEDMONT AND COASTAL PLAIN. SINCE CATEGORICAL POP ARE IN PLACE... NO NEED FOR ADJUSTMENTS. QPF OF 1 TO LOCALLY 2 INCHES EXPECTED 12Z THU THROUGH 12 FRI. THE HEAVY RAIN THREAT WITH DEEP CONVECTION SHOULD SHIFT SLOWLY SE THROUGH THE REGION REACHING THE SANDHILLS AND COASTAL PLAIN THURSDAY NIGHT... WHILE LINGERING IN THE PIEDMONT. THEN FRIDAY... NUMEROUS SHOWERS AND THUNDERSTORMS WILL AGAIN DEVELOP... ALONG AND AHEAD OF THE LEFT-OVER CONVECTIVE BOUNDARIES/COLD FRONT. IT APPEARS THAT THE NW PIEDMONT SHOULD HAVE THE LOWER POP (BUT STILL IN THE LIKELY RANGE FRIDAY). TO THE EAST AND SOUTH... THROUGH MUCH OF CENTRAL AND EASTERN NC... NUMEROUS SHOWERS AND THUNDERSTORMS ARE EXPECTED AS THE COLD FRONT SLOWS TO A CRAWL... FOCUSING HIGH PW`S OF 2+ INCHES... AND LOW LEVEL CONVERGENCE. QPF OF 1.5 TO 2 INCHES LOOKS A GOOD BET... WITH LOCALLY HIGHER TOTALS. THIS WOULD GIVE QPF 2 DAY TOTALS OF 2 TO 4 INCHES... NOT WHAT AGRICULTURAL INTERESTS NEED AT THIS POINT. FRIDAY NIGHT AND SATURDAY... THE COLD FRONT SHOULD STALL OVER THE COASTAL PLAIN... WHERE THE HIGHEST POP WILL RESIDE. LOCALLY HEAVY RAIN THREAT WILL CONTINUE. NUMEROUS SHOWERS AND THUNDERSTORMS SHOULD BECOME MORE SCATTERED BY SATURDAY ACROSS THE NW PIEDMONT (AWAY FROM THE STALLED BOUNDARY TO THE SE). LOWS 70-73. HIGHS LOWER TO MID 80S. SUNDAY AND MONDAY... THE FOCUS TURNS TO THE EVOLUTION OF TS CHANTAL. IT APPEARS THAT THE BEST FORECAST FOR OUR REGION WOULD BE TO FOLLOW THE ENSEMBLE MEANS AND MODEL TRENDS. THE ANTECEDENT VERY WET CONDITIONS OVER OUR REGION CERTAINLY WOULD BE PROBLEMATIC TO SAY THE LEAST SHOULD CHANTAL BECOME AN ISSUE FOR NC. HOWEVER... THE ENSEMBLES GENERALLY TURN WHAT IS LEFT OF THIS SYSTEM WESTWARD AS HEIGHTS ARE FORECAST TO RISE ALONG THE EAST COAST FROM BUILDING WESTERN ATLANTIC RIDGING BY SUNDAY AND MONDAY. AS OF THIS FORECAST... IT APPEARS THAT MID/UPPER RIDGING OVER THE WESTERN ATLANTIC MAY BUILD WESTWARD INTO EASTERN NC ENOUGH TO STEER THIS SYSTEM WESTWARD (GULF COAST) BY SUNDAY AND MONDAY. THIS WOULD ALLOW THE NUMEROUS SHOWERS AND STORMS TO BECOME SCATTERED... MAINLY DIURNALLY DRIVEN SHOWERS AND THUNDERSTORMS SUNDAY AND MONDAY FOR OUR REGION. HIGHS WOULD ALSO GO UP TO NEAR NORMAL BY THEN AS WELL. LOWS 70-73. HIGHS 85-88. && .AVIATION /12Z TUESDAY THROUGH SATURDAY/... AS OF 745 AM TUESDAY... CONTINUED VERY HUMID SOUTHERLY FLOW AROUND BERMUDA HIGH PRESSURE WILL MAINTAIN A FAMILIAR...PERSISTENT PATTERN. THAT IS...LIFR-IFR CEILINGS AND VFR-MVFR VISIBILITY RESTRICTIONS TRANSITIONING THROUGH MVFR RANGE TO VFR BETWEEN 13-15Z...WITH MOSTLY AFTERNOON-EVENING THUNDERSTORMS...MOST LIKELY TODAY AT KFAY/KRWI/KRDU. LIFR-IFR CEILINGS AND MVFR VISIBILITY RESTRICTIONS WILL THEN REDEVELOP IN THE VERY HUMID REGIME LATE TONIGHT. OUTLOOK... INCREASED SHOWER AND STORM COVERAGE...AND MORE PROLONGED MVFR CONDITIONS THAN PREVIOUS DAYS - INTO EARLY AFTERNOON - WILL DEVELOP BY FRI-SAT...AS A STRONG UPPER LEVEL TROUGH AND SURFACE COLD FRONT MOVE INTO OUR REGION. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...HARTFIELD NEAR TERM...HARTFIELD/MWS SHORT TERM...MWS LONG TERM...BADGETT AVIATION...MWS
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1033 AM EDT TUE JUL 9 2013 .SYNOPSIS... THE WEATHER WILL REMAIN UNSETTLED ACROSS THE LOWER GREAT LAKES AND OHIO VALLEY TODAY AND TONIGHT AHEAD OF A COLD FRONT THAT WILL MOVE THROUGH THE AREA ON WEDNESDAY. THURSDAY AND FRIDAY HIGH PRESSURE AND DRY STABLE AIR WILL BUILD IN. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... NUMEROUS FLOOD WARNINGS REMAIN IN EFFECT FROM 2-4 INCHES OF HEAVY RAIN THAT FELL OVERNIGHT. FORTUNATELY DRIER AIR ALOFT IS OVERSPREADING THE AREA AS SEEN ON THE 12Z DTX SOUNDING WITH LARGER SCALE SUBSIDENCE IN THE WAKE OF LAST NIGHTS SHORTWAVE. EXPECT SEVERAL HOURS OF DRY CONDITIONS THROUGH MID AFTERNOON WITH INSTABILITY STARTING TO CREEP BACK UP FROM THE SOUTH LATE IN THE DAY AS DEWPOINTS REMAIN IN THE LOW 70S. WE COULD START TO SEE SOME SCATTERED SHOWERS AND THUNDERSTORMS DEVELOP IN OUR SOUTHWESTERN COUNTIES THAT RECEIVED THE HEAVY RAIN OVERNIGHT BY LATE AFTERNOON. WE ARE ALSO KEEPING AN EYE ON THE CONVECTION MOVING INTO WESTERN ILLINOIS AS IT APPROACHES LATER TODAY FOR BOUNDARIES THAT MAY HELP KICK OFF SHOWERS AND THUNDERSTORMS ALONG THE STALLED WARM FRONTAL BOUNDARY ACROSS INDIANA/WESTERN OHIO. OTHERWISE ANOTHER ROUND OF RAIN IS STILL EXPECTED OVERNIGHT INTO TOMORROW AND THE THREAT FOR FLOODING CONTINUES. ORIGINAL...FOR THE MORNING EXPECT THE TREND IN PLACE TO SLOWLY CONTINUE WITH PRECIP MOVING EAST/SOUTHEAST OF THE AREA AND DRIER AIR MOVING IN FROM THE NORTHWEST. SHOULD EVENTUALLY SEE SOME SS TODAY HOWEVER HRRR DOES SHOW SCATTERED CONVECTION REDEVELOPING IN THE MOIST UNSTABLE AIR STILL IN PLACE ACROSS THE AREA LATER THIS AFTERNOON. BEST CHANCES WOULD BE WEST/SWRN COUNTIES. WILL BRING CHANCE POPS BACK TO THE SRN/SWRN COUNTIES WITH SLIGHT CHANCE POPS ON THE NORTH SIDE OF THAT. HIGHS NEAR GUIDANCE. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/... FOLLOWED MIX OF HPC/NAM AND SREF GUIDANCE FOR THE SHORT TERM. COLD FRONT IS ON THE WAY FOR WEDNESDAY AND TONIGHT AHEAD OF THE FRONT MODELS SHOWED A COUPLE SHORT WAVES MOVING ACROSS THE REGION. EXPECTING SHOWERS/THUNDERSTORMS MOVING IN FROM THE WEST LATE EVENING OR EARLY IN THE NIGHT AND PERSISTING THROUGH MUCH OF WEDNESDAY. WOULD ANTICIPATE THE NEED FOR A FLOOD WATCH BUT GIVEN THE CURRENT HEADLINE WILL WAIT FOR DAY SHIFT TO REEVALUATE. GIVEN HPC QPF VALUES INCREASED MAV GUIDANCE POPS AGREEING MORE WITH THE SREF CATEGORICAL GUIDANCE TONIGHT AND WEDNESDAY. THURSDAY AND FRIDAY SUN AND DRY. && .LONG TERM /SATURDAY THROUGH MONDAY/... MODELS HAVE BEEN SLOWLY TRENDING TO A DRIER WEEKEND WITH THE CENTRAL U.S. RIDGE TRYING TO NOSE INTO THE LOWER GREAT LAKES AND THE TROUGH SHIFTING TO THE EAST COAST. THIS WILL PUT IS IN THE MIDDLE AND WILL KEEP THE DRY WEEKEND FORECAST AND THE LOW PRECIP CHANCES FOR MONDAY WITH AN INCREASE IN MOISTURE. WILL PUT TEMPS IN BETWEEN GFS AND ECMWF GUIDANCE AS A COMPROMISE SEEMS BEST RIGHT NOW. THAT WILL GIVE US SEASONABLE TEMPS FOR THE WEEKEND IN THE LOWER TO MID 80S. && .AVIATION /14Z TUESDAY THROUGH SATURDAY/... RELATIVE LULL TODAY IN SHOWERS/TS ALTHOUGH A FEW MIGHT START TO POP UP AGAIN LATE THIS AFTERNOON FOR FDY/MFD/CAK. SOME MORNING BR TO START ALONG WITH SOME MVFR CIGS. EXPECTING IMPROVEMENT TO VFR FOR MIDDAY AND INTO THE AFTERNOON. WINDS WILL SHIFT TO THE WEST TODAY AND BRING IN SOMEWHAT DRIER AIR. TONIGHT THOUGH SHOWERS/TS TO BREAK OUT ONCE AGAIN AS FLOW COMES BACK AROUND TO THE SSW. A COLD FRONT WILL APPROACH FOR WEDNESDAY SO MORE WIDESPREAD SHRA/TS TOWARD DAWN AND BEYOND. SOME OF THOSE COULD BE STRONG TO SEVERE. HEAVY RAIN AND IFR CONDITIONS WITHIN TS. .OUTLOOK...NON-VFR EXPECTED IN SHOWERS AND THUNDERSTORMS THROUGH WEDNESDAY NIGHT. && .MARINE... A RELATIVE LULL IN THE THUNDERSTORM CHANCES FOR TODAY. SOUTH-SW FLOW WILL CONTINUE WITH A NEARLY STATIONARY BOUNDARY JUST NORTH OF THE LAKE. LOW PRESSURE WILL TRACK ACROSS THE NORTHERN LAKES WEDNESDAY AND TAKE A COLD FRONT ACROSS LAKE ERIE WITH ANOTHER ROUND OF THUNDERSTORMS...SOME OF WHICH WILL BE ON THE STRONG SIDE. WINDS MAY PICK UP ENOUGH TO NEED A SMALL CRAFT ADV WITH THIS SYSTEM. SOME CHOP POSSIBLE WEDNESDAY AHEAD OF THE FRONT FOR THE EASTERN NEARSHORE WITH SW FLOW ALONG THE LENGTH OF THE LAKE. BETTER CHANCES FOR SMALL CRAFT ADV CONDITIONS IN THE NORTHWEST FLOW AFTER THE FRONT. THE WEATHER SETTLES DOWN THURSDAY THROUGH SATURDAY WITH HIGH PRESSURE OVER THE CENTRAL GREAT LAKES. WILL HAVE A NORTHERLY FLOW THAT WILL BECOME ENE BY SATURDAY AS THE HIGH SHIFTS EAST...REMAINING NORTH OF LAKE ERIE. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. MARINE...NONE. && $$ SYNOPSIS...TK NEAR TERM...KEC/TK SHORT TERM...TK/KOSARIK LONG TERM...OUDEMAN AVIATION...OUDEMAN MARINE...OUDEMAN
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
751 AM EDT TUE JUL 9 2013 .SYNOPSIS... THE WEATHER WILL REMAIN UNSETTLED ACROSS THE LOWER GREAT LAKES AND OHIO VALLEY TODAY AND TONIGHT AHEAD OF A COLD FRONT THAT WILL MOVE THROUGH THE AREA ON WEDNESDAY. THURSDAY AND FRIDAY HIGH PRESSURE AND DRY STABLE AIR WILL BUILD IN. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... UPDATE...CANCELLED THE FLASH FLOOD WATCH. ALTHOUGH FLOODING IS ONGOING...WILL HANDLY WITH CURRENT WARNINGS. THREAT OF ADDITIONAL FLOOD PRODUCING RAIN HAS DIMINISHED FOOR TODAY. ORIGINAL...MADE ADJUSTMENT TO THE FLOOD WATCH TRIMMING THE NORTHERN COUNTIES BUT EXTENDING IT A FEW HOURS INTO THE MORNING FOR THE REMAINING SOUTHERN COUNTIES. RADAR SHOWS THE HEAVY RAIN MOVING SLOWLY EAST HOWEVER MORE SHOWERS HAVE DEVELOPED ON THE WEST SIDE OF THE MAIN CONVECTION ACROSS PORTIONS OF CRAWFORD/WYANDOT AND MARION COUNTIES. RAIN STILL OCCURRING ACROSS THE CENTRAL LAKESHORE BUT IS NOT INTENSE ENOUGH TO CAUSE FLOODING. FOR THE MORNING EXPECT THE TREND IN PLACE TO SLOWLY CONTINUE WITH PRECIP MOVING EAST/SOUTHEAST OF THE AREA AND DRIER AIR MOVING IN FROM THE NORTHWEST. SHOULD EVENTUALLY SEE SOME SS TODAY HOWEVER HRRR DOES SHOW SCATTERED CONVECTION REDEVELOPING IN THE MOIST UNSTABLE AIR STILL IN PLACE ACROSS THE AREA LATER THIS AFTERNOON. BEST CHANCES WOULD BE WEST/SWRN COUNTIES. WILL BRING CHANCE POPS BACK TO THE SRN/SWRN COUNTIES WITH SLIGHT CHANCE POPS ON THE NORTH SIDE OF THAT. HIGHS NEAR GUIDANCE. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/... FOLLOWED MIX OF HPC/NAM AND SREF GUIDANCE FOR THE SHORT TERM. COLD FRONT IS ON THE WAY FOR WEDNESDAY AND TONIGHT AHEAD OF THE FRONT MODELS SHOWED A COUPLE SHORT WAVES MOVING ACROSS THE REGION. EXPECTING SHOWERS/THUNDERSTORMS MOVING IN FROM THE WEST LATE EVENING OR EARLY IN THE NIGHT AND PERSISTING THROUGH MUCH OF WEDNESDAY. WOULD ANTICIPATE THE NEED FOR A FLOOD WATCH BUT GIVEN THE CURRENT HEADLINE WILL WAIT FOR DAY SHIFT TO REEVALUATE. GIVEN HPC QPF VALUES INCREASED MAV GUIDANCE POPS AGREEING MORE WITH THE SREF CATEGORICAL GUIDANCE TONIGHT AND WEDNESDAY. THURSDAY AND FRIDAY SUN AND DRY. && .LONG TERM /SATURDAY THROUGH MONDAY/... MODELS HAVE BEEN SLOWLY TRENDING TO A DRIER WEEKEND WITH THE CENTRAL U.S. RIDGE TRYING TO NOSE INTO THE LOWER GREAT LAKES AND THE TROUGH SHIFTING TO THE EAST COAST. THIS WILL PUT IS IN THE MIDDLE AND WILL KEEP THE DRY WEEKEND FORECAST AND THE LOW PRECIP CHANCES FOR MONDAY WITH AN INCREASE IN MOISTURE. WILL PUT TEMPS IN BETWEEN GFS AND ECMWF GUIDANCE AS A COMPROMISE SEEMS BEST RIGHT NOW. THAT WILL GIVE US SEASONABLE TEMPS FOR THE WEEKEND IN THE LOWER TO MID 80S. && .AVIATION /12Z TUESDAY THROUGH SATURDAY/... RELATIVE LULL TODAY IN SHOWERS/TS ALTHOUGH A FEW MIGHT START TO POP UP AGAIN LATE THIS AFTERNOON FOR FDY/MFD/CAK. SOME MORNING BR TO START ALONG WITH SOME MVFR CIGS. EXPECTING IMPROVEMENT TO VFR FOR MIDDAY AND INTO THE AFTERNOON. WINDS WILL SHIFT TO THE WEST TODAY AND BRING IN SOMEWHAT DRIER AIR. TONIGHT THOUGH SHOWERS/TS TO BREAK OUT ONCE AGAIN AS FLOW COMES BACK AROUND TO THE SSW. A COLD FRONT WILL APPROACH FOR WEDNESDAY SO MORE WIDESPREAD SHRA/TS TOWARD DAWN AND BEYOND. SOME OF THOSE COULD BE STRONG TO SEVERE. HEAVY RAIN AND IFR CONDITIONS WITHIN TS. .OUTLOOK...NON-VFR EXPECTED IN SHOWERS AND THUNDERSTORMS THROUGH WEDNESDAY NIGHT. && .MARINE... A RELATIVE LULL IN THE THUNDERSTORM CHANCES FOR TODAY. SOUTH-SW FLOW WILL CONTINUE WITH A NEARLY STATIONARY BOUNDARY JUST NORTH OF THE LAKE. LOW PRESSURE WILL TRACK ACROSS THE NORTHERN LAKES WEDNESDAY AND TAKE A COLD FRONT ACROSS LAKE ERIE WITH ANOTHER ROUND OF THUNDERSTORMS...SOME OF WHICH WILL BE ON THE STRONG SIDE. WINDS MAY PICK UP ENOUGH TO NEED A SMALL CRAFT ADV WITH THIS SYSTEM. SOME CHOP POSSIBLE WEDNESDAY AHEAD OF THE FRONT FOR THE EASTERN NEARSHORE WITH SW FLOW ALONG THE LENGTH OF THE LAKE. BETTER CHANCES FOR SMALL CRAFT ADV CONDITIONS IN THE NORTHWEST FLOW AFTER THE FRONT. THE WEATHER SETTLES DOWN THURSDAY THROUGH SATURDAY WITH HIGH PRESSURE OVER THE CENTRAL GREAT LAKES. WILL HAVE A NORTHERLY FLOW THAT WILL BECOME ENE BY SATURDAY AS THE HIGH SHIFTS EAST...REMAINING NORTH OF LAKE ERIE. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. MARINE...NONE. && $$ SYNOPSIS...TK NEAR TERM...TK SHORT TERM...TK/KOSARIK LONG TERM...OUDEMAN AVIATION...OUDEMAN MARINE...OUDEMAN
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
741 AM EDT TUE JUL 9 2013 .SYNOPSIS... THE WEATHER WILL REMAIN UNSETTLED ACROSS THE LOWER GREAT LAKES AND OHIO VALLEY TODAY AND TONIGHT AHEAD OF A COLD FRONT THAT WILL MOVE THROUGH THE AREA ON WEDNESDAY. THURSDAY AND FRIDAY HIGH PRESSURE AND DRY STABLE AIR WILL BUILD IN. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... UPDATE...MADE ADJUSTMENT TO SKY GRIDS TODAY THROUGH THE NEXT COUPLE DAYS. ALSO ADJUSTED POPS AND WX BASED ON CURRENT RADAR. ORIGINAL...MADE ADJUSTMENT TO THE FLOOD WATCH TRIMMING THE NORTHERN COUNTIES BUT EXTENDING IT A FEW HOURS INTO THE MORNING FOR THE REMAINING SOUTHERN COUNTIES. RADAR SHOWS THE HEAVY RAIN MOVING SLOWLY EAST HOWEVER MORE SHOWERS HAVE DEVELOPED ON THE WEST SIDE OF THE MAIN CONVECTION ACROSS PORTIONS OF CRAWFORD/WYANDOT AND MARION COUNTIES. RAIN STILL OCCURRING ACROSS THE CENTRAL LAKESHORE BUT IS NOT INTENSE ENOUGH TO CAUSE FLOODING. FOR THE MORNING EXPECT THE TREND IN PLACE TO SLOWLY CONTINUE WITH PRECIP MOVING EAST/SOUTHEAST OF THE AREA AND DRIER AIR MOVING IN FROM THE NORTHWEST. SHOULD EVENTUALLY SEE SOME SS TODAY HOWEVER HRRR DOES SHOW SCATTERED CONVECTION REDEVELOPING IN THE MOIST UNSTABLE AIR STILL IN PLACE ACROSS THE AREA LATER THIS AFTERNOON. BEST CHANCES WOULD BE WEST/SWRN COUNTIES. WILL BRING CHANCE POPS BACK TO THE SRN/SWRN COUNTIES WITH SLIGHT CHANCE POPS ON THE NORTH SIDE OF THAT. HIGHS NEAR GUIDANCE. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/... FOLLOWED MIX OF HPC/NAM AND SREF GUIDANCE FOR THE SHORT TERM. COLD FRONT IS ON THE WAY FOR WEDNESDAY AND TONIGHT AHEAD OF THE FRONT MODELS SHOWED A COUPLE SHORT WAVES MOVING ACROSS THE REGION. EXPECTING SHOWERS/THUNDERSTORMS MOVING IN FROM THE WEST LATE EVENING OR EARLY IN THE NIGHT AND PERSISTING THROUGH MUCH OF WEDNESDAY. WOULD ANTICIPATE THE NEED FOR A FLOOD WATCH BUT GIVEN THE CURRENT HEADLINE WILL WAIT FOR DAY SHIFT TO REEVALUATE. GIVEN HPC QPF VALUES INCREASED MAV GUIDANCE POPS AGREEING MORE WITH THE SREF CATEGORICAL GUIDANCE TONIGHT AND WEDNESDAY. THURSDAY AND FRIDAY SUN AND DRY. && .LONG TERM /SATURDAY THROUGH MONDAY/... MODELS HAVE BEEN SLOWLY TRENDING TO A DRIER WEEKEND WITH THE CENTRAL U.S. RIDGE TRYING TO NOSE INTO THE LOWER GREAT LAKES AND THE TROUGH SHIFTING TO THE EAST COAST. THIS WILL PUT IS IN THE MIDDLE AND WILL KEEP THE DRY WEEKEND FORECAST AND THE LOW PRECIP CHANCES FOR MONDAY WITH AN INCREASE IN MOISTURE. WILL PUT TEMPS IN BETWEEN GFS AND ECMWF GUIDANCE AS A COMPROMISE SEEMS BEST RIGHT NOW. THAT WILL GIVE US SEASONABLE TEMPS FOR THE WEEKEND IN THE LOWER TO MID 80S. && .AVIATION /12Z TUESDAY THROUGH SATURDAY/... RELATIVE LULL TODAY IN SHOWERS/TS ALTHOUGH A FEW MIGHT START TO POP UP AGAIN LATE THIS AFTERNOON FOR FDY/MFD/CAK. SOME MORNING BR TO START ALONG WITH SOME MVFR CIGS. EXPECTING IMPROVEMENT TO VFR FOR MIDDAY AND INTO THE AFTERNOON. WINDS WILL SHIFT TO THE WEST TODAY AND BRING IN SOMEWHAT DRIER AIR. TONIGHT THOUGH SHOWERS/TS TO BREAK OUT ONCE AGAIN AS FLOW COMES BACK AROUND TO THE SSW. A COLD FRONT WILL APPROACH FOR WEDNESDAY SO MORE WIDESPREAD SHRA/TS TOWARD DAWN AND BEYOND. SOME OF THOSE COULD BE STRONG TO SEVERE. HEAVY RAIN AND IFR CONDITIONS WITHIN TS. .OUTLOOK...NON-VFR EXPECTED IN SHOWERS AND THUNDERSTORMS THROUGH WEDNESDAY NIGHT. && .MARINE... A RELATIVE LULL IN THE THUNDERSTORM CHANCES FOR TODAY. SOUTH-SW FLOW WILL CONTINUE WITH A NEARLY STATIONARY BOUNDARY JUST NORTH OF THE LAKE. LOW PRESSURE WILL TRACK ACROSS THE NORTHERN LAKES WEDNESDAY AND TAKE A COLD FRONT ACROSS LAKE ERIE WITH ANOTHER ROUND OF THUNDERSTORMS...SOME OF WHICH WILL BE ON THE STRONG SIDE. WINDS MAY PICK UP ENOUGH TO NEED A SMALL CRAFT ADV WITH THIS SYSTEM. SOME CHOP POSSIBLE WEDNESDAY AHEAD OF THE FRONT FOR THE EASTERN NEARSHORE WITH SW FLOW ALONG THE LENGTH OF THE LAKE. BETTER CHANCES FOR SMALL CRAFT ADV CONDITIONS IN THE NORTHWEST FLOW AFTER THE FRONT. THE WEATHER SETTLES DOWN THURSDAY THROUGH SATURDAY WITH HIGH PRESSURE OVER THE CENTRAL GREAT LAKES. WILL HAVE A NORTHERLY FLOW THAT WILL BECOME ENE BY SATURDAY AS THE HIGH SHIFTS EAST...REMAINING NORTH OF LAKE ERIE. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...FLASH FLOOD WATCH UNTIL 9 AM EDT THIS MORNING FOR OHZ027>030- 036-037-047. PA...NONE. MARINE...NONE. && $$ SYNOPSIS...TK NEAR TERM...TK SHORT TERM...TK/KOSARIK LONG TERM...OUDEMAN AVIATION...OUDEMAN MARINE...OUDEMAN
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
646 AM EDT TUE JUL 9 2013 .SYNOPSIS... THE WEATHER WILL REMAIN UNSETTLED ACROSS THE LOWER GREAT LAKES AND OHIO VALLEY TODAY AND TONIGHT AHEAD OF A COLD FRONT THAT WILL MOVE THROUGH THE AREA ON WEDNESDAY. THURSDAY AND FRIDAY HIGH PRESSURE AND DRY STABLE AIR WILL BUILD IN. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... UPDATE...MADE ADJUSTMENT TO SKY GRIDS TODAY THROUGH THE NEXT COUPLE DAYS. ALSO ADJUSTED POPS AND WX BASED ON CURRENT RADAR. ORIGINAL...MADE ADJUSTMENT TO THE FLOOD WATCH TRIMMING THE NORTHERN COUNTIES BUT EXTENDING IT A FEW HOURS INTO THE MORNING FOR THE REMAINING SOUTHERN COUNTIES. RADAR SHOWS THE HEAVY RAIN MOVING SLOWLY EAST HOWEVER MORE SHOWERS HAVE DEVELOPED ON THE WEST SIDE OF THE MAIN CONVECTION ACROSS PORTIONS OF CRAWFORD/WYANDOT AND MARION COUNTIES. RAIN STILL OCCURRING ACROSS THE CENTRAL LAKESHORE BUT IS NOT INTENSE ENOUGH TO CAUSE FLOODING. FOR THE MORNING EXPECT THE TREND IN PLACE TO SLOWLY CONTINUE WITH PRECIP MOVING EAST/SOUTHEAST OF THE AREA AND DRIER AIR MOVING IN FROM THE NORTHWEST. SHOULD EVENTUALLY SEE SOME SS TODAY HOWEVER HRRR DOES SHOW SCATTERED CONVECTION REDEVELOPING IN THE MOIST UNSTABLE AIR STILL IN PLACE ACROSS THE AREA LATER THIS AFTERNOON. BEST CHANCES WOULD BE WEST/SWRN COUNTIES. WILL BRING CHANCE POPS BACK TO THE SRN/SWRN COUNTIES WITH SLIGHT CHANCE POPS ON THE NORTH SIDE OF THAT. HIGHS NEAR GUIDANCE. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/... FOLLOWED MIX OF HPC/NAM AND SREF GUIDANCE FOR THE SHORT TERM. COLD FRONT IS ON THE WAY FOR WEDNESDAY AND TONIGHT AHEAD OF THE FRONT MODELS SHOWED A COUPLE SHORT WAVES MOVING ACROSS THE REGION. EXPECTING SHOWERS/THUNDERSTORMS MOVING IN FROM THE WEST LATE EVENING OR EARLY IN THE NIGHT AND PERSISTING THROUGH MUCH OF WEDNESDAY. WOULD ANTICIPATE THE NEED FOR A FLOOD WATCH BUT GIVEN THE CURRENT HEADLINE WILL WAIT FOR DAY SHIFT TO REEVALUATE. GIVEN HPC QPF VALUES INCREASED MAV GUIDANCE POPS AGREEING MORE WITH THE SREF CATEGORICAL GUIDANCE TONIGHT AND WEDNESDAY. THURSDAY AND FRIDAY SUN AND DRY. && .LONG TERM /SATURDAY THROUGH MONDAY/... MODELS HAVE BEEN SLOWLY TRENDING TO A DRIER WEEKEND WITH THE CENTRAL U.S. RIDGE TRYING TO NOSE INTO THE LOWER GREAT LAKES AND THE TROUGH SHIFTING TO THE EAST COAST. THIS WILL PUT IS IN THE MIDDLE AND WILL KEEP THE DRY WEEKEND FORECAST AND THE LOW PRECIP CHANCES FOR MONDAY WITH AN INCREASE IN MOISTURE. WILL PUT TEMPS IN BETWEEN GFS AND ECMWF GUIDANCE AS A COMPROMISE SEEMS BEST RIGHT NOW. THAT WILL GIVE US SEASONABLE TEMPS FOR THE WEEKEND IN THE LOWER TO MID 80S. && .AVIATION /12Z TUESDAY THROUGH SATURDAY/... SCATTERED SHOWERS AND THUNDERSTORMS REMAIN FOR THE REMAINDER OF THE NIGHT. IFR WITHIN THESE SHRA/TS. SOME AREAS OF MVFR AS WELL. BIGGEST TASK IS WHETHER NON VFR CEILINGS OF VSBYS WILL DEVELOP IN A MORE WIDESPREAD NATURE. LATEST SREF BRINGS IN MVFR AND SOME IFR ACROSS SOUTHERN MI ACROSS ONTARIO AND INTO NW PA. HAVE LEANED THIS WAY AND HAVE BROUGHT THE LOWEST CONDITIONS INTO TOLEDO. WITH DOWNSLOPE FLOW DID NOT GO TOO LOW AT ERIE. EVEN THOUGH THERE IS PLENTY OF LOW LEVEL MOISTURE...LIGHT WIND AND CURRENT CIGS SHOULD PREVENT VSBY FROM GETTING TOO LOW. START MOST AT MVFR IN MID MORNING...IMPROVING TO VFR. MOST OF THE SHOWERS LOOK TO BE OVER BY AROUND 12Z...BUT AREA MAY GET NEW DEVELOPMENT AGAIN TOWARD YNG/CAK LATE THIS AFTERNOON. UNSURE ABOUT FDY/MFD. AGAIN THIS IS FOCUSING ON THE TIMES WITH THE BEST CHANCES...STILL COULD SEE A SHRA/TS AT JUST ABOUT ANY TIME. .OUTLOOK...NON-VFR EXPECTED IN SHOWERS AND THUNDERSTORMS THROUGH WEDNESDAY NIGHT. && .MARINE... A RELATIVE LULL IN THE THUNDERSTORM CHANCES FOR TODAY. SOUTH-SW FLOW WILL CONTINUE WITH A NEARLY STATIONARY BOUNDARY JUST NORTH OF THE LAKE. LOW PRESSURE WILL TRACK ACROSS THE NORTHERN LAKES WEDNESDAY AND TAKE A COLD FRONT ACROSS LAKE ERIE WITH ANOTHER ROUND OF THUNDERSTORMS...SOME OF WHICH WILL BE ON THE STRONG SIDE. WINDS MAY PICK UP ENOUGH TO NEED A SMALL CRAFT ADV WITH THIS SYSTEM. SOME CHOP POSSIBLE WEDNESDAY AHEAD OF THE FRONT FOR THE EASTERN NEARSHORE WITH SW FLOW ALONG THE LENGTH OF THE LAKE. BETTER CHANCES FOR SMALL CRAFT ADV CONDITIONS IN THE NORTHWEST FLOW AFTER THE FRONT. THE WEATHER SETTLES DOWN THURSDAY THROUGH SATURDAY WITH HIGH PRESSURE OVER THE CENTRAL GREAT LAKES. WILL HAVE A NORTHERLY FLOW THAT WILL BECOME ENE BY SATURDAY AS THE HIGH SHIFTS EAST...REMAINING NORTH OF LAKE ERIE. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...FLASH FLOOD WATCH UNTIL 9 AM EDT THIS MORNING FOR OHZ027>030- 036-037-047. PA...NONE. MARINE...NONE. && $$ SYNOPSIS...TK NEAR TERM...TK SHORT TERM...TK/KOSARIK LONG TERM...OUDEMAN AVIATION...OUDEMAN MARINE...OUDEMAN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
744 AM EDT TUE JUL 9 2013 .SYNOPSIS... A BERMUDA HIGH ANCHORED OFF THE EASTERN SEABOARD WILL CONTINUE TO FEED VERY WARM AND HUMID AIR NORTHWARD INTO THE COMMONWEALTH. DAILY CHANCES OF SHOWERS AND THUNDERSTORMS WILL PERSIST UNTIL A COLD FRONT PASSES THURSDAY. && .NEAR TERM /UNTIL 4 PM THIS AFTERNOON/... BROAD SHORT WAVE TROUGH WHICH SEEMS UNDERDONE BY THE MDLS IS DROPPING ESE FROM OHIO EARLY THIS MORNING. MID LEVEL WINDS INCREASE FROM THE SW SLIGHTLY THIS MORNING...AND MOISTURE POOLING AT THE AXIS OF THE TROUGH WILL SLIDE ACROSS THE CWA FROM W-E AS MAINLY LIGHT SHOWERS AND WIDELY SCT/EMBEDDED THUNDER. HEAVIER RAIN ON A TRACK TO MOVE TO THE SOUTH OF THE AREA. HRRR SEEMS TO HAVE A GOOD HANDLE ON RECENT TRENDS. IT PORTRAYS THE DEATH OF MUCH OF THIS FIRST BATCH OF LIGHT RAIN AS IT MOVES TO THE EAST...THEN A RE-DEVELOPMENT OF CONVECTION AS DAYTIME HEATING COMBINES WITH BREAKS IN THE CLOUD COVER TO BUBBLE UP SHRA/TSRA. WITH CLOUDS AND SCT/NMRS SHOWERS AROUND...WILL KEEP MAXE TEMPS LOOKING LIKE YESTERDAY/MON. DEWPOINTS ALSO MOVE LITTLE SO ANOTHER SEASONAL JULY DAY IS IN STORE. && .SHORT TERM /4 PM THIS AFTERNOON THROUGH 6 PM WEDNESDAY/... THE SHORT WAVE PUSHES TO THE EAST THIS EVENING AND A DECREASE IN SHRA/TSRA IS EXPECTED FOR MOST OF THE OVERNIGHT HOURS. WILL JUST LEAVE IN SCT/ISOLD WORDING FOR NOW. HEIGHTS DROP THROUGH THE NIGHT...THOUGH. THIS OCCURS AS A BROADER AND MORE-SYNOPTIC SCALE TROUGH AXIS NEARS FROM THE GREAT LAKES/UPPER MIDWEST. THE MOISTURE PLUME PUSHES RIGHT BACK INTO THE AREA LATE TONIGHT AND HANGS OUT OVERHEAD THROUGH THE END OF THE PERIOD. A COOL FRONT REACHES THE LOWER LAKES LATE WED. ALL THIS PUTS THE AREA IN THE WARM SECTOR AND ALLOWS THE SERN COS TO MAKE ANOTHER RUN AT 90F. THE CLOUDS WILL BE THE TEMPERING FACTOR ON WEDNESDAY...KNOCKING A FEW DEGS OFF THE POTENTIAL MAXES. THEY WILL ALSO PLAY A ROLE IN THE POTENTIAL FOR SEVERE WEATHER ON WEDNESDAY AFTN/EVENING. CAPES O/O OF 2000 ARE POSSIBLE...BUT MAY NOT BE REALIZED. ALSO...WIND FIELD IS NOT ALL THAT STRONG AS SPC POINTS OUT. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... COOL FRONT SHOULD PUSH INTO THE AEA EARLY WED NIGHT AND MIGHT CLEAR THE SERN COS BY THURSDAY SUNRISE. HOWEVER...POPS IN THE CHC RANGE STILL A STRONG FORECAST FOR THE SERN HALF OF THE AREA LATE WED NIGHT AND ALL THURS DUE TO UNCERTAINTY OF HOW FAR S THE DRIER AIR WILL BE ABLE TO NUDGE THE CONVECTION. MEDIUM RANGE MODEL AND ENSEMBLE GUIDANCE CONTINUES TO ADVERTISE ANOTHER ANOMALOUS MERIDIONAL LARGE SCALE PATTERN EARLY IN THE PERIOD...AS TROUGHING/UPPER LOW DROPS SOUTHWARD ALONG/WEST OF THE APPALACHIANS...AND FOUR CORNERS RIDGE MAINTAINS ITS POSITION. THE AMPLIFIED FLOW OVER THE CONUS SHOULD EVOLVE AND REVERT BACK TO A MORE TYPICAL SUMMERTIME CONFIGURATION DURING THE SECOND HALF OF THE PERIOD...AS THE JET STREAM RETREATS NORTHWARD TO THE U.S./CANADIAN BORDER AND LARGE SUBTROPICAL RIDGE TAKES UP RESIDENCE OVER MUCH OF THE LOWER 48. IN TERMS OF SENSIBLE WX IMPACTS...A SURGE OF MUCH DRIER/BELOW NORMAL PWAT AIR SHOULD FOLLOW BEHIND THE COLD FROPA ON THURSDAY. THIS SHOULD PROVIDE A BRIEF BREAK IN THE HUMID/MUGGY CONDITIONS LATER THIS WEEK. THE FRONTAL BOUNDARY APPEARS TO STALL-OUT OVER THE SRN MID-ATLC STATES BEFORE DRIFTING BACK TO THE WEST TOWARD THE APPALACHIANS...INTERCEPTING A MODEST /NEAR-NORMAL PWATS/ MOISTURE FLOW AROUND THE BERMUDA HIGH. AS SUCH...LOOK FOR TEMPERATURES AND TREND UPWARD INTO NEXT WEEK ACCOMPANIED BY RETURNING SUMMERTIME HUMIDITY. && .AVIATION /12Z TUESDAY THROUGH SATURDAY/... BANDS OF MAINLY LIGHT SHOWERS ARE MOVING ACROSS CENTRAL PA MAKING FOR A MOIST START TO THE MORNING. WIDESPREAD MVFR CIGS AND POOR VSBYS IN FOG WILL PERSIST THROUGH 14Z MOST TAF SITES. PREDOMINANTLY VFR CONDS ARE LIKELY LATER THIS MORNING AND INTO EARLY AFTN. HOWEVER...ISOLD LATE DAY THUNDERSTORM IMPACTS ARE POSSIBLE IN ASSOCIATION WITH LINGERING TROUGH OF LOW PRES OVR THE AREA. OUTLOOK... WED...AM LOW CIGS POSS NW MTNS. SCT TSRA IMPACTS POSSIBLE. THU...AM LOW CIGS POSS W MTNS. SCT TSRA IMPACTS POSSIBLE. FRI-SAT...NO SIG WX EXPECTED. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...DANGELO NEAR TERM...DANGELO SHORT TERM...DANGELO LONG TERM...STEINBUGL AVIATION...FITZGERALD/GARTNER
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
1048 AM CDT TUE JUL 9 2013 .UPDATE...REST OF TODAY MAIN FORECAST CHALLENGE TODAY IS WHETHER OR NOT WE WILL HAVE ADDITIONAL ISO/SCT SHOWER AND STORM DEVELOPMENT LATER TODAY ACROSS NORTHERN/NORTHEASTERN SD. LAST NIGHTS ACTIVITY IS WELL EAST OF THE REGION AND CURRENTLY AFFECTING MN/WI. ALTHOUGH...MAIN UPPER LEVEL WAVE IS STILL SPINNING ACROSS FAR SOUTHERN CANADA WITH THE SHORTWAVE ENERGY EXPECTED TO MOVE EAST ACROSS THE DAKOTAS TODAY INTO THIS EVENING. THERE HAVE BEEN A FEW SPOTTY SHOWERS ACROSS CENTRAL SD...NORTHWEST SD AND SOUTHWEST ND. SFC FRONT HAS CLEARED THE CWA SO WILL BE HARD TO FOCUS ANYTHING AT THE SFC. 12Z NAM ALONG WITH THE LATEST RUN OF THE HRRR KEEPS THINGS COMPLETELY DRY TODAY...WITH ONLY A FEW ISO SHOWERS MOVING SOUTHEAST INTO THE AREA SHORTLY AFTER 00Z THIS EVENING. OTHER HI-RES MESOSCALE MODELS SHOW A FEW WDLY SCT STORMS DEVELOPING LATER TODAY. THE LATEST HRRR RUN IS DEPICTING THE CURRENT SITUATION VERY NICELY AND STARTING TO THINK IT MAY BE ON TO SOMETHING. HEDGED A BIT ON THE DRY SIDE FOR POPS TODAY BUT DID NOT WANT TO GO COMPLETELY DRY BASED ON THE UPPER WAVE ALONE...AND THE FACT THAT ITS ENERGY STILL HAS TO SWING THROUGH THE REGION LATER TODAY. A COUPLE LIGHT SHOWERS ARE ONGOING ALONG THE ND/SD BORDER TO THE NORTHWEST. ALSO...SFC DEWPOINTS ARE STILL IN THE 60S. CANNOT COMPLETELY RULE OUT SOMETHING LATER TODAY BUT NOT REAL EXCITED ABOUT CHANCES AT THIS POINT. IF ANYTHING...EXPECT IT TO BE ISO/WDLY SCT. && .PREVIOUS DISCUSSION... .SHORT TERM...TUESDAY THROUGH THURSDAY MAIN WEATHER CHALLENGE IN THE SHORT TERM IS PRECIP CHANCES TODAY. MODELS ARE A LITTLE SLOW MOVING OVERNIGHT CONVECTION ASSOCIATED WITH A TROF OF LOW PRESSURE THROUGH. THIS IS HAVING RESIDUAL EFFECTS ON THE QPF FIELD THIS MORNING. LEFT IN SOME POPS ACROSS THE FAR EAST. STUCK CLOSER TO HI-RES MODELS WHICH HAVE A MOSTLY DRY MORNING ACROSS THE AREA. THE SFC COLD FRONT SWEEPS INTO THE EAST THIS AFTERNOON BRINGING CHANCES FOR MORE STORMS. BIGGEST FORECAST CHALLENGE WITH THIS ROUND OF STORMS IS HOW FAR WEST THEY WILL EXPAND. FOR NOW HAVE POPS CONFINED TO EAST OF THE JAMES RIVER VALLEY AS INDICATED ON THE HRRR. HIGH PRESSURE BUILDS IN TUESDAY NIGHT AND WEDNESDAY. HIGH SHIFTS TO THE SOUTH AND EAST WEDNESDAY EVENING AHEAD OF ANOTHER TROF. MODELS INDICATE INCREASED INSTABILITY AHEAD OF THE TROF WITH THE GFS RAMPING UP THE LLJ WEST OF THE MISSOURI RIVER. KEPT SLIGHT CHANCE POPS ACROSS THE SOUTHWEST CWA WED NIGHT...BUT IF THE LLJ PANS OUT MAY NEED TO EXPAND THE POPS NORTH. TEMPS WILL BE SUPPRESSED BEHIND THIS INITIAL TROF WITH HIGHS IN THE LOWER 80S TODAY AND WEDNESDAY. AHEAD OF THE NEXT TROF SOUTHERLY FLOW WILL BOOST TEMPS BACK INTO THE MID 80S TO LOWER 90S ON THURSDAY. .LONG TERM...THURSDAY NIGHT THROUGH MONDAY THE MODELS ALL SHOW GOOD AGREEMENT THROUGH THE LONG TERM WITH THE UPPER LEVEL FLOW PATTERN ACROSS OUR REGION. THE PERIOD STARTS OUT WITH A SHARP 50H RIDGE AXIS EXTENDING ACROSS OUR REGION AND INTO SOUTHERN CANADA WITH LOW PRESSURE TROUGHING ALONG THE PACIFIC NORTHWEST COAST. THIS UPPER RIDGE WILL FLATTEN OUT DURING THE LONG TERM AS THE WEST COAST TROUGHING MOVES ALONG THE NORTHERN US BORDER FROM SATURDAY THROUGH SUNDAY. A BROAD AREA OF UPPER LEVEL HIGH PRESSURE WILL THEN EXTEND ACROSS MOST OF THE SOUTHERN US THROUGH MONDAY WITH OUR REGION ON THE NORTHERN EDGE. FRIDAY WILL STILL BE THE WARMEST DAY IN THE LONG TERM UNDER THE UPPER LEVEL RIDGE WITH TEMPERATURES APPROACHING 100 DEGREES ON FRIDAY AFTERNOON SOUTHWEST IN THE CWA. TEMPERATURES WILL REMAIN ABOVE NORMAL THROUGH THE WEEKEND IN THE MID 80S TO THE LOWER 90S AND MAY BE JUST IN THE 80S ON MONDAY. HAVE CHANCES OF STORMS FROM MAINLY FRIDAY NIGHT THROUGH SUNDAY NIGHT ACROSS THE CWA WITH THE UPPER LEVEL LOW PRESSURE TROUGH SLIDING ACROSS THE REGION ALONG WITH A SURFACE BOUNDARY PUSHING THROUGH. && .AVIATION... 12Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS VFR CONDITIONS ARE EXPECTED AT ALL TERMINALS THROUGH TODAY AND TONIGHT. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. && $$ UPDATE...TMT SHORT TERM...WISE LONG TERM...MOHR AVIATION...MOHR WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
612 AM CDT TUE JUL 9 2013 .SHORT TERM...(TODAY THROUGH TONIGHT) ISSUED AT 315 AM CDT TUE JUL 9 2013 MAIN CONCERN WILL BE TRACK OF PLAINS THUNDERSTORM COMPLEX THIS MORNING/TODAY...THEN SEVERE POTENTIAL GOING THIS AFTERNOON. LOOP OF WATER VAPOR IMAGERY THIS MORNING ALONG WITH RAP 500MB ANALYSIS SHOWS A FAIRLY VIGOROUS MID-LEVEL TROUGH MOVING OUT OF MT INTO THE DAKOTAS...WHILE ANOTHER WEAKER WAVE WAS NOTED ACROSS CENTRAL NEB. 925-850MB MOISTURE TRANSPORT AHEAD OF THESE WAVES WAS PRODUCING A BROKEN LINE COMPLEX OF THUNDERSTORMS EXTENDING FROM EASTERN ND/SD...INTO EASTERN NEB. THIS COMPLEX OF STORMS WAS MOVING EAST AT 30-35KT...MAKING INROADS TOWARD THE AREA. SIMPLE EXTRAPOLATION BRINGS THIS COMPLEX INTO SOUTHEAST MN/NORTHEAST IA AROUND 12Z/7AM-ISH. ARX/HRRR/NMM WRF MODELS DID A PRETTY GOOD JOB INITIALIZING THIS CONVECTION AND REMAIN IN FAIRLY DECENT AGREEMENT THROUGH THE DAY TODAY. HAVE TRENDED THE FORECAST TO MATCH UP WITH A BLEND OF THESE SOLUTIONS. APPEARS THE COMPLEX OF STORMS WILL MAINTAIN ITSELF...COMING ACROSS THE AREA THIS MORNING AS 925-850MB MOISTURE TRANSPORT INCREASES/NOSES INTO THE REGION. THIS COMPLEX OF STORMS HAS A HISTORY OF 30-50KT WINDS ASSOCIATED WITH IT OVER SD. SO...CANNOT RULE OUT SOME BORDERLINE SEVERE WINDS AS IT ROLLS INTO OUR AREA. COULD BE INTERESTING GOING INTO THIS AFTERNOON AS THE WRF MODELS SHOW THIS COMPLEX DEVELOPING A FAIRLY SIGNIFICANT MCV STRUCTURE. THIS IN TURN HAS THE POTENTIAL OF PRODUCING A MINI-OUTFLOW/COLD FRONT ON ITS SOUTHWEST FLANK IN THE 18-21Z TIME FRAME. WITH AMPING SHEAR IN THE 30-40KT RANGE DUE TO THE MCV AND MORE THAN AMPLE CAPE IN THE 4000-5500J/KG RANGE...LOOKING FOR THE POSSIBILITY OF A LINE OF SEVERE STORMS WITH DAMAGING WINDS DEVELOPING ACROSS CENTRAL/SOUTHWEST WI THIS AFTERNOON. THIS OF COURSE WILL ALL DEPEND ON HOW MUCH CLOUD IS PRESENT WHICH COULD AFFECT THE AMOUNT OF AVAILABLE INSTABILITY REALIZED. THE POTENTIAL IS DEFINITELY THERE AND WILL HAVE TO BE WATCHED CLOSELY. ANOTHER THING TO WATCH IS HEAVY RAINFALL POTENTIAL WITH MUGGY AIRMASS IN PLACE AND PRECIPITABLE WATER IN THE 2-2.25 INCH RANGE. THIS COULD AID IN TORRENTIAL DOWNPOURS OUT OF THE STORMS AND SOME LOCALIZED PONDING OF WATER IN POOR DRAINAGE AREAS. LOOKING FOR THE MAIN COLD FRONT TO THEN SLIDE SOUTHEAST ACROSS THE AREA IN THE 00-06Z TIME FRAME. UNCERTAIN ON HOW THIS IS GOING TO PLAY OUT WITH THE POTENTIAL FOR SEVERE STORMS ALREADY GOING THROUGH THE AREA THIS AFTERNOON. ATMOSPHERE COULD BE FAIRLY STABILIZED BEHIND THIS CONVECTION AND COLD FRONT COULD SLIP THROUGH WITH NO CONVECTION. APPEARS HIGHEST POTENTIAL FOR EVENING CONVECTION MAY BE ALONG AND NORTH OF I-94 WHERE BETTER 500-300MB PV-ADVECTION WILL EXIST. EXPECTING COLD FRONT AND ASSOCIATED CONVECTION TO PUSH EAST OF THE AREA AROUND DAYBREAK AS HIGH PRESSURE BUILDS IN FROM THE DAKOTAS. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 315 AM CDT TUE JUL 9 2013 HIGH PRESSURE WILL PRODUCE VERY PLEASANT WEATHER CONDITIONS ACROSS THE AREA WEDNESDAY AND THURSDAY. LOOK FOR HIGHS IN THE 75-80 DEGREE RANGE ON WEDNESDAY AND UPPER 70S/LOWER 80S ON THURSDAY. MUCH LOWER HUMIDITY LEVELS WILL ALSO BE NOTED AS DEWPOINTS HOVER IN THE 50S. PLAN ON WARMER TEMPERATURES ON FRIDAY ALONG WITH INCREASING HUMIDITY LEVEL AS THE HIGH SLIDES OFF TO THE EAST AND SOUTH WINDS SET UP ACROSS THE AREA. LOOK FOR HIGHS IN THE 80S WITH A FEW READINGS FLIRTING WITH THE 90 DEGREE MARK ACROSS SOUTHEAST MN. EC/GFS ACTUALLY IN PRETTY GOOD AGREEMENT GOING INTO THE WEEKEND. BOTH MOVE A COLD FRONT INTO THE UPPER MISSISSIPPI RIVER REGION BY SUNDAY MORNING...THEN HANG IT UP ACROSS WI INTO CENTRAL IA BY MONDAY. THIS WILL PRODUCE A CHANCE OF SHOWERS AND THUNDERSTORMS FROM FRIDAY NIGHT STRAIGHT THROUGH MONDAY. OTHERWISE...LOOK FOR TEMPERATURES TO BE RIGHT AROUND NORMAL LEVELS IN THE 80S. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING) ISSUED AT 611 AM CDT TUE JUL 9 2013 TWO COMPLEXES OF STORMS HEADED TOWARD THE AREA THIS MORNING. THE FIRST IS MOVING NORTHEAST OUT OF NORTHERN IOWA AND SHOULD BEGIN TO IMPACT KRST RIGHT AROUND 12Z AND THEN GET INTO KLSE NEAR 14Z. BRIEF HEAVY RAINS ARE OCCURRING WITH THESE STORMS WITH THE POTENTIAL TO DROP THE VISIBILITY TO IFR FOR A WHILE WITH MVFR CEILINGS. THE NEXT COMPLEX IS MOVING QUICKLY EAST ACROSS MINNESOTA AND LOOKS LIKE IT SHOULD JOIN UP WITH THE NORTHERN IOWA COMPLEX NEAR THE MISSISSIPPI RIVER. THIS COMPLEX IS PRODUCING VERY SIMILAR CONDITIONS BUT DOES HAVE A BIT MORE POTENTIAL TO PRODUCE SOME WIND GUSTS. TO ACCOUNT FOR THESE TWO COMPLEXES HAVE INCLUDED A 3 TO 4 HOUR TEMPO GROUP FOR BOTH AIRPORTS WITH SOME GUSTY WINDS AND IFR CONDITIONS. HOW QUICKLY THE ACTIVITY MOVES EAST IS STILL A LITTLE QUESTIONABLE SO HAVE HELD ONTO A VCSH INTO THE AFTERNOON. THE NEXT ROUND OF STORMS BECOMES POSSIBLE LATE THIS AFTERNOON INTO THE EVENING AS A COLD FRONT MOVES THROUGH THE AREA. STILL A LOT OF UNCERTAINTY WHETHER THIS ROUND OF STORMS WILL EVEN OCCUR. THE 09.08Z HRRR IS QUICKER TO BRING THE FRONT THROUGH THIS AFTERNOON AND THUS DOES NOT ALLOW AS MUCH CAPE TO DEVELOP. BECAUSE OF THIS...IT PASSES THE FRONT THROUGH WITH JUST A FEW SHOWERS ALONG IT. THE 09.06Z NAM IS SLOWER WITH THE FRONT ALLOWING MORE CAPE TO DEVELOP AND HAS ANOTHER ROUND OF STORMS ALONG THE FRONT DURING THE EVENING. NOT KNOWING HOW LONG THE CLOUDS WILL REMAIN PAST THE MORNING ACTIVITY HAVE OPTED TO REMAIN WITH A VCTS DURING THE EVENING FOR BOTH SITES. THE CLOUDS SHOULD QUICKLY CLEAR OUT JUST BEFORE 06Z AS HIGH PRESSURE STARTS TO BUILD IN AND SPREADS DRIER AIR INTO THE REGION. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...DAS LONG TERM....DAS AVIATION...04
AREA FORECAST DISCUSSION
NWS PUEBLO CO
333 PM MDT TUE JUL 9 2013 .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 253 PM MDT TUE JUL 9 2013 ...A FEW STRONG STORMS POSSIBLE TOMORROW... CURRENTLY...CONVECTION A BIT SLOW TO GET GOING...BUT SCT STORMS DEVELOPING OVER THE MTS...AND LINE OF CU ALONG AND N OF HGWY 50 IS STARTING TO SEE ISOLD CONVECTION DEVELOP. WILL CONTINUE TO SEE ISOLD STORMS THIS AFTERNOON AND EVENING OVER THE PLAINS...WITH STORMS MOVING TO THE S AND E. NOT EXPECTING A LOT OF RAIN WITH MOST OF THESE STORMS...ALTHOUGH A COUPLE OVER THE FAR SERN GRASSLANDS COULD BE A LITTLE MORE EFFICIENT RAIN PRODUCERS. THE HIGH RES WRF AND HRRR CONTINUE TO SHOW THE POTENTIAL FOR REDEVELOPMENT OF ISOLD SHOWERS AND STORMS OVER THE PALMER DVD AFTER 04Z TONIGHT...LINGERING INTO THE EARLY MORNING HOURS. AM SOMEWHAT SKEPTICAL AS THERE IS NO REAL UPSTREAM DISTURBANCE TO KICK THINGS OFF...BUT WILL MAINTAIN LOW/ISOLD POPS THROUGH TONIGHT FOR THAT AREA. TOMORROW...THE PRECIP/POPS FORECAST GETS TRICKIER. THE GFS HAS VERY LITTLE QPF OVER THE PLAINS TOMORROW...WHILE THE NAM HAS WIDESPREAD PRECIP...ESPECIALLY OVER THE ERN PORTIONS OF OUR CWA. HOWEVER...EVEN THE NAM HAS BACKED OFF ON THE EXTENT OF COOLER AIR MOVING INTO OUR AREA. LATEST MOS GUIDANCE FOR KPUB IN IN THE MID TO UPPER 90S. THE QUESTION IS TO WHAT EXTENT THE WEAK FRONTAL PUSH WILL MOVE INTO OUR AREA. OUTSIDE THE FRONT AND MODEST UPSLOPE...THERE IS NOT MUCH OF A TRIGGER IN THE FLOW ALOFT TO SUPPORT WIDESPREAD QPF. AM BEING A BIT CAUTIOUS WITH POPS TOMORROW...KEEPING CHANCE POPS OVER THE PLAINS IN THE AFTERNOON...BUT LATER SHIFTS MAY NEED TO DO SOME REDUCTIONS IF THE MODELS CONTINUE A TREND TOWARDS FEWER STORMS. THERE STILL SHOULD BE FAIRLY WIDESPREAD CONVECTION OVER THE ERN MTS...WITH LIGHT S TO SE FLOW ACROSS THE PLAINS IN THE AFTERNOON. DEWPOINTS SHOULD BE IN THE LOWER 50S TO POSSIBLY UPPER 50S CLOSER TO THE KS BORDER. THE LIGHT WINDS AND INCREASED MOISTURE SHOULD KEEP TEMPS FROM RISING AS HIGH AS MOS GUIDANCE SUGGESTS. DEPENDING ON HOW FAR THE FRONTAL BOUNDARY MAKES IT INTO SE CO...THERE ALSO COULD BE A MARGINAL THREAT OF SVR WX TOMORROW...ESPECIALLY E OF I-25 AND N OF HGWY 50 IN THE LATE AFTERNOON AND EARLY EVE. THE HIGHEST THREAT WILL BE OVER KIOWA COUNTY LATE IN THE DAY...WHERE BULK SHEARS WILL APPROACH 40 KTS OR SO AND MOISTURE WILL BE GREATEST. COULD SEE SOME HAIL FROM THE STRONGEST STORMS...ALONG WITH GUSTY WINDS AND BRIEF HEAVY RAINFALL. ROSE .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 253 PM MDT TUE JUL 9 2013 ...UPSWING IN THUNDERSTORMS WEDNESDAY EVENING...WITH MONSOON CONTINUING FOR THE NEXT SEVERAL DAYS... INTERACTION OF BOUNDARY MOVING THROUGH THE PLAINS AND MONSOON MOISTURE PROMISES AN UPSWING IN THUNDERSTORM ACTIVITY LASTING INTO WEDNESDAY EVENING. THEN...THURSDAY THROUGH SATURDAY...THE MONSOON REGROUPS OVER THE MOUNTAINS...MAINLY AFFECTING AREAS ALONG AND WEST OF I-25. HIGH PRESSURE CENTERS OVER EASTERN COLORADO AND WESTERN KANSAS DURING THIS TIME...DIRECTING THE FLOW OF MOISTURE INTO THOSE AREAS. BEGINNING SUNDAY...THE HIGH MAY SHIFT EAST FAR ENOUGH TO LET THE MONSOON SPILL OUT ONTO THE PLAINS...BRINGING AN UPSWING IN ACTIVITY TO THOSE AREAS. PRIMARY CONCERNS OVER THE NEXT SEVERAL DAYS WILL BE THE IMPACT OF HEAVY RAINS ON AREA BURN SCARS. IF HEAVY RAIN DEVELOPS OVER ANY OF THE SCARS...FLASH FLOODING AND DEBRIS FLOWS WILL BE POSSIBLE. OTHER CONCERNS THROUGH THE PERIOD WILL BE LIGHTNING...WIND GUSTS TO AROUND 55 MPH AND LOCAL SMALL HAIL. ITS STILL SEVERAL DAYS OFF...BUT THE GREATEST POTENTIAL FOR HEAVY RAINFALL WOULD APPEAR TO MOVE IN OVER THE WEEKEND AS UPPER HIGH PRESSURE SHIFTS OVER EASTERN COLORADO...ALLOWING MONSOONAL MOISTURE INFLUX INTO WESTERN COLORADO ON THE WEST SIDE OF THE HIGH. IN MANY CASES THE RAIN WILL BE BENEFICIAL...BUT THE RISK FOR FLASH FLOODING AND DEBRIS FLOWS IN AND AROUND AREA BURN SCARS WILL LIKELY INCREASE DURING THIS PERIOD. LW && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING) ISSUED AT 253 PM MDT TUE JUL 9 2013 VFR CONDITIONS EXPECTED TO CONTINUE AT THE TAF SITES THROUGH TOMORROW. AS MENTIONED IN PREVIOUS DISCUSSION...STILL THE THREAT OF ISOLD TS THROUGH EARLY EVENING...AND POSSIBLY LINGERING THROUGH TONIGHT OVER THE PALMER DVD AND VC KCOS. TOMORROW...SHOULD SEE A BETTER CHANCE OF STORMS ESPECIALLY ALONG I-25 AND EWD...FROM 18Z THROUGH 03Z WED EVE. A FEW OF THESE STORMS COULD BE ON THE STRONG SIDE..ESPECIALLY E OF I-25 AND N OF HGWY 50. HAIL UP TO AN INCH AND LOCALLY HEAVY RAINFALL...ALONG WITH WIND GUSTS TO 50 KTS...WILL BE POSSIBLE WITH THE STRONGEST STORMS TOMORROW. ROSE && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...ROSE LONG TERM...LW AVIATION...ROSE
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1048 AM MDT TUE JUL 9 2013 .UPDATE...WATER VAPOR IMAGERY...MORNING RAOBS AND INTEGRATED PRECIPITABLE WATER PRODUCTS ALL INDICATE A MUCH DRIER AIRMASS OVER THE FORECAST AREA TODAY. MODEL SOUNDINGS FROM THE NAM AND RAP ALSO SHOW MID-LEVEL CAPPING OVER MOST OF THE PLAINS THROUGH THE AFTERNOON. THE EXCEPTION TO THIS IS EAST OF A LIMON-AKRON LINE WHERE 1000-1500 J/KG OF CAPE WILL BE PRESENT DURING THE EARLY EVENING. MOUNTAIN AREAS SHOULD STILL SEE ISOLATED THUNDERSTORMS THIS AFTERNOON...BUT THE SHOWERS WILL RAPIDLY EVAPORATE AS THEY MOVE OFF THE FOOTHILLS...SIMILAR TO YESTERDAY AFTERNOON. WILL UPDATE THE FORECAST TO REMOVE MENTION OF THUNDERSTORMS ON THE PLAINS THIS AFTERNOON AND EVENING. WILL HOLD ONTO ISOLATED THUNDERSTORMS OVER THE EASTERN TIER OF COUNTIES AFTER 00Z. HOT TEMPERATURES ARE GOING TO BE THE MAIN STORY THIS AFTERNOON...AS WE HAVE ALREADY REACHED 92 AT KDEN. THE RECORD FOR THE DAY IS 98...WHICH MAY TUMBLE DURING THE MID-LATE AFTERNOON. && .AVIATION...NO AVIATION IMPACTS THROUGH THIS AFTERNOON AND EVENING. WINDS WILL SWITCH TO LIGHT AND NORTHERLY DURING THE AFTERNOON...AHEAD OF A MORE SIGNIFICANT FRONTAL PUSH LATER THIS EVENING. && .HYDROLOGY...AFTERNOON SHOWERS WILL ONLY PRODUCE LIGHT AMOUNTS OF RAIN...SO NO PROBLEMS ARE EXPECTED. && .PREV DISCUSSION... /ISSUED 249 AM MDT TUE JUL 9 2013/ SHORT TERM...AN UPPER LEVEL HIGH WILL BE OVER SWRN CO WITH WEAK WNW FLOW ALOFT ACROSS NRN CO. WATER VAPOR IMAGERY SHOWS BEST PLUME OF SUBTROPICAL MOISTURE ACROSS SRN CO WHICH IS FCST TO STAY IN THE SAME GENERAL AREA. AT THE SFC A WK PRE FNTL BNDRY WILL MOVE ACROSS NERN CO TODAY AND FLUSH OUT LOW LVL MOISTURE EXCEPT POSSIBLY OVER THE FAR NERN CORNER. AT THIS TIME TSTM THREAT OVER NERN CO LOOKS RATHER ISOLD AND HIGH BASED. OVER THE HIGHER TERRAIN WILL KEEP IN WDLY SCT TSTMS. AS FOR HIGHS READINGS WILL RISE ANOTHER FEW DEGREES WITH TEMPS IN THE 95 TO 100 DEGREE RANGE OVER THE PLAINS. RECORD HIGH AT DENVER IS 98 WHICH COULD BE TIED OR BKN. FOR TONIGHT A CDFNT WILL MOVE ACROSS NERN CO OVERNIGHT AND BRING AN INCREASE IN LOW LVL MOISTURE ALL THE WAY BACK INTO THE FOOTHILLS BY 12Z. AT THIS POINT REALLY CAN`T SEE ANYTHING TO ENHANCE CONVECTION HOWEVER IF A WK DISTURBANCE WERE TO MOVE ACROSS THEN THAT COULD CHANGE THINGS DRAMATICALLY. FOR NOW WILL JUST KEEP LOW POPS IN OVERNIGHT ACROSS THE PLAINS. LONG TERM...NO SIGNIFICANT CHANGES AT THIS TIME. ON WEDNESDAY LOW LEVEL MOISTURE WILL INCREASE ACROSS NORTHEAST COLORADO FOLLOWING THE PASSAGE OF A WEAK COLD FRONT. SFC WINDS WILL ALSO BACK AROUND TO THE SE WHICH WOULD LEAD TO THE DEVELOPMENT OF A DENVER CYCLONE IN THE LATE AFTN/EVNG. MDLS VARY GREATLY REGARDING THE FCST QPF AMOUNTS BUT THEY ALL INDICATE RAINFALL. IN ADDITION...SHEAR PROFILE INDICATIVE OF SOME SEVERE TSTM POTENTIAL AS WELL. FCST CAPES FM THE GFS BUFFER SOUNDINGS AROUND 1000 J/KG AT KDEN AROUND 21Z...WITH 1600 J/KG FM THE NAM12. PW VALUES FM BOTH SOUNDINGS IN EXCESS OF ONE INCH...SO WILL SIDE WITH THE HEAVIER QPF AMOUNTS FM THE GFS BUFFER SOUNDINGS. SIMILAR VALUES FCST FOR THE NERN PLAINS OF CO AS WELL. ON THURSDAY THE AMS WILL BE DRIER ALONG THE URBAN CORRIDOR...WITH BETTER POTENTIAL OVER THE NERN PLAINS WHERE THE BEST LOW LEVEL MOISTURE WILL BE. THE RIDGE ITSELF WILL MOVE FM THE FOUR CORNERS REGION 00Z THU TO THE OKLAHOMA/TEXAS PANHANDLES BY 00Z FRI. THE CENTER OF THE RIDGE WILL SHIFT A BIT FURTHER EASTWARD BY THE WEEKEND. BEST CHC OF TSTMS DURING THE WEEK WILL BE WEDNESDAY AFTN/EVNG...MAYBE A LITTLE LESS COVERAGE ON THURSDAY. FRIDAY THROUGH SUNDAY...SUBTROPICAL MOISTURE WILL INCREASE ACROSS WRN AND NRN CO AND FRIDAY THROUGH SUNDAY AS WILL THE CHC OF THUNDERSTORMS. THE MOISTURE IS PROGGED TO MOVE FM BAJA INTO CO IN THAT TIME. HEAVY RAIN POTENTIAL WILL EXIST ACROSS THE CWFA EACH AFTN/EVNG...ESPECIALLY OVER THE WEEKEND...WITH THE STORMS. AVIATION...SFC WINDS WERE SSW EARLY THIS MORNING BUT SHOULD BECOME LIGHT WNW AROUND 14Z AND THEN MORE NNE BY 17Z. BY LATE AFTN THEY MAY BECOME MORE ELY AND THEN SELY BY 01Z. AT THIS TIME TSTM THREAT LOOKS LOW THRU THIS AFTN INTO THE EARLY EVENING HOURS SO WILL NOT MENTION IN THE TAF. FOR TONIGHT A COLD FRONT WILL MOVE INTO THE AREA AFTER MIDNIGHT. THERE IS SOME POTENTIAL FOR STRATUS IN THE 12Z-15Z TIMEFRAME ON WED. HYDROLOGY...ISOLD TO WIDELY SCATTERED THUNDERSTORMS WILL DEVELOP THIS AFTERNOON HOWEVER THEY WILL BE RATHER HIGH BASED SO RAINFALL AMOUNTS SHOULD BE UNDER A QUARTER INCH. && .BOU WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...DANKERS LONG TERM....99 AVIATION...DANKERS
AREA FORECAST DISCUSSION
NWS TAUNTON MA
421 PM EDT TUE JUL 9 2013 .SYNOPSIS... A FEW SHOWERS AND THUNDERSTORMS WITH LOCALLY HEAVY RAINFALL WILL AFFECT THE REGION AT TIMES THROUGH FRIDAY. AT THIS POINT...THE SHOWERS AND THUNDERSTORMS LOOK TO BE MOST WIDESPREAD ON THURSDAY. MAINLY DRY AND LESS HUMID WEATHER LOOKS FINALLY ARRIVE BY THE WEEKEND. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... 430 PM UPDATE... UPDATED FORECAST TO ACCOUNT FOR CURRENT TRENDS OTHERWISE THE FORECAST REMAINS ON TRACK FOR THE LATE AFTERNOON. INTERESTING SET-UP ACROSS THE REGION THIS AFTERNOON. LINGERING BOUNDARY FROM YESTERDAYS BACK DOOR COLD FRONT IS STATIONED NORTH OF CQX TO HFD THEN JETS NORTHWARD ACROSS THE BERKSHIRES. THIS BOUNDARY WILL REMAINS NEARLY STATIONARY AND WILL CONTINUE TO BE THE FOCUS ON WHERE CONVECTION WILL CONTINUE. TEMPERATURES NORTH OF THE BOUNDARY ARE IN THE UPPER 60S TO MID 70S...WHILE SOUTH OF THE BOUNDARY TEMPS HAVE WARMED INTO THE MID 80S. 20Z RADAR IMAGERY SHOWS SCATTERED SHOWERS AND THUNDER THAT HAS DEVELOPED ALONG THE BOUNDARY. ALSO SEVERAL OUTFLOW BOUNDARIES FROM TODAYS THUNDERSTORMS ARE INTERSECTING EVERYWHERE. INTERESTING TO SEE HOW STORMS WILL EVOLVE LATER THIS AFTERNOON. BELIEVE THAT THEY WILL CONTINUE TO FIRE ACROSS NH AND ALONG THE CAPE AND SE MASS WHERE THE BETTER CONVERGENCE IS LOCATED AS WELL AS THE ENVIRONMENT HAS NOT BEEN WORKED OVER AS MUCH. ML CAPE VALUES ARE BETWEEN 1000-1500 J/KG ACROSS RHODE ISLAND AND THE CT VALLEY AND THE BERKSHIRES. SHEAR IS NEARLY NON-EXISTENT SO THESE STORMS WILL HARDLY MOVE AND WITH PWAT VALUES NEAR 1.7 TO 2 INCHES EXPECT HEAVY DOWNPOURS WITH THESE CELLS. VERY LOCALIZED FLASH FLOODING IS THE MAIN CONCERN WITH WIND GUSTS BEING THE SECOND CONCERN. EXPECT STORMS TO CONTINUE TO FIRE OFF OF THIS BOUNDARY OVER THE NEXT SEVERAL HOURS. LATEST MESOSCALE MODELS ALSO SUPPORT THIS THEORY AS THE HRRR SEEMS TO BE DOING A GREAT JOB WITH ONGOING CONVECTION. TONIGHT... CURRENT CONVECTION ACROSS THE REGION SHOULD SLOWLY WANE AFTER SUNSET AS DIURNAL HEATING IS LOST. A FEW SHOWERS MAY CONTINUE TO LINGER OVERNIGHT BUT THE THREAT FOR STRONG TO SEVERE STORMS WILL BE LOW. MAIN CONCERN WILL BE THE POTENTIAL FOR LOW CLOUDS AND FOG AGAIN. BELIEVE THAT BOTH COAST LINES WILL BE AT RISK AS EASTERLY FLOW IS ACROSS THE EAST COAST AND SOUTHERLY FLOW ONTO THE SOUTH COAST. THIS WILL KEEP THE MOISTURE STREAMING INTO THE REGION ALLOWING FOR FOG TO DEVELOP. OTHERWISE SURFACE LOW WILL MOVE EASTWARD OVERNIGHT PUSHING THE CURRENT BOUNDARY THAT IS DRAPED ACROSS SE MA/RI AND INTO CT NORTHWARD AS A WARM FRONT OVERNIGHT AND INTO TOMORROW MORNING. OVERNIGHT TEMPS WILL BE PLEASANT NORTH OF THE BOUNDARY...IN THE LOW TO MID 60S. SOUTH OF THE BOUNDARY TEMPS WILL BE IN THE UPPER 60S TO LOW 70S. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/... TOMORROW... A LOT OF UNCERTAINTY STILL IS IN PLACE FOR TOMORROW. UPPER LEVEL LOW OVER THE UPPER GREAT LAKES WILL CONTINUE THE TROUGH OVER THE REGION. QUICK MOVING SHORTWAVE WILL MOVE THROUGH THE FLOW ALLOWING FROM SOME SORT OF LIFT FOR THE REGION. HOWEVER LOOKING AT FORECAST GUIDANCE IT SEEMS THE AREA THAT MAY SEE THE BETTER POTENTIAL FOR STORMS WILL BE OUT WEST ACROSS THE CT VALLEY/ORH HILLS. THIS REGION WILL HAVE THE BETTER INSTABILITY ONCE THE LOW STRATUS DECK BREAKS UP. CURRENT BOUNDARY ACROSS THE REGION NOW WILL LIFT NORTHWARD AS A FORM OF A WARM FRONT WHEN THE SHORTWAVE APPROACHES. THIS WILL ALLOW FOR TEMPS TO WARM RIGHT BACK UP INTO THE MID TO UPPER 80S. BELIEVE THAT STORMS WILL MAINLY BE DIURNALLY DRIVE DURING THE DAY. WITH LACK OF SHEAR AND FLOW ALOFT BELIEVE THESE STORMS WILL BE NEARLY STATIONARY AND WITH PWATS IN THE 1.5 TO 2 INCHES...HEAVY DOWNPOURS WILL BE THE MAIN THREAT. CAPE VALUES SHOULD BE HIGHER THEN TODAY SO GUSTY WINDS MAY ALSO BE A POTENTIAL ONCE THUNDERSTORMS BEGIN TO COLLAPSE. STORMS SHOULD BEGIN TO WANE AFTER SUNSET ONCE DIURNAL HEATING IS LOST. TOMORROW NIGHT... AFTER A QUICK LULL IN CONVECTION MODELS ARE INDICATING THAT STORMS WILL FIRE UP OVERNIGHT AND LAST INTO THE THURSDAY. SYNOPTIC MODELS ARE STRUGGLING WITH PLACEMENT OF THE COLD FRONT AS THE GFS BRINGS IT ACROSS SNE FASTER THEN THE GENERAL TREND. ALSO AM HESITANT AS THESE SORT OF FRONTS HAVE THE TENDENCY TO STALL. HOWEVER IF THE FRONT MOVES TOWARDS THE REGION LATE TOMORROW NIGHT INTO THURSDAY MORNING THEN THE OVERNIGHT HOURS MAY BE ACTIVE. FORECAST GUIDANCE SHOWS ELEVATED INSTABILITY ACROSS THE REGION AS SHOWALTERS ARE -2C COMBINED WITH DEEP MOISTURE AND A SOURCE OF LIFT WHICH COULD HAVE STORMS FIRING OVERNIGHT. EXACT COVERAGE AND PLACEMENT IS STILL UNKNOWN AS THE TIMING IS THE OVERALL QUESTION. HOWEVER MAIN THREAT APPEARS TO BE HEAVY DOWNPOURS. HAVE CONTEMPLATED WITH THE ISSUANCE OF A FLASH FLOOD WATCH BUT HAVE COLLABORATION WITH SURROUND OFFICES DECIDED TO HOLD OFF AS THERE IS STILL A LOT OF UNCERTAINTY. && .LONG TERM /THURSDAY THROUGH TUESDAY/... HEADLINES... * HEAVY RAIN AND POTENTIAL FLOODING FOR THURSDAY * RAINS LINGER TO THE SOUTHEAST INTO FRIDAY * A RETURN OF MORE SEASONABLE WEATHER INTO THE WEEKEND AND EARLY WEEK */OVERVIEW AND MODEL CONSENSUS... THOUGH MODELS AGREE UPON A BROAD RIDGING PATTERN EVOLVING ACROSS THE CONUS...THEY REMAIN AT ODDS AND STRUGGLE WITH HANDLING ENERGY ALONG THE NORTHERN PERIPHERY OF THE RIDGE. CONSEQUENTIALLY...RUN-TO-RUN CONSISTENCY HAS BEEN POOR AS OF LATE WITH HANDLING THE EVOLUTION OF THE MID- TO UPPER-LEVEL ENERGY DIVING SOUTHEAST OUT OF CANADA AND ACROSS THE NORTHEASTERN CONUS...POTENTIALLY EVOLVING INTO A CLOSED LOW THAT RETROGRADES SOUTH AND WEST. HPC/WPC MAINTAINS CONTINUITY WITH THEIR FORECAST...GOING WITH A 09.0Z ENSEMBLE BLEND...NOTING THE UNCERTAIN TRACK OF TROPICAL STORM CHANTAL. WILL FOLLOW SUIT INCORPORATING THEIR FORECAST INTO A BLEND OF THE 09.12Z FORECAST GUIDANCE. */DAY-TO-DAY DETAILS... */THURSDAY INTO THURSDAY NIGHT... SURFACE COLD FRONT SLOWED ACROSS SOUTHERN NEW ENGLAND AGAINST RIDGING OF HIGH PRESSURE OVER THE WESTERN ATLANTIC WILL BE FORCED OFFSHORE DURING THE EVENING HOURS AND OVERNIGHT AS THE MID- TO UPPER- LEVEL TROUGH AXIS PUSHES SOUTHEAST OUT OF CANADA INTO THE NORTHEAST CONUS. FEEL 09.12Z GFS IS TOO FAST WITH THIS FEATURE. CHANCE TO LIKELY POPS WARRANTED THURSDAY WITH DEEP-LAYER FORCING COUPLED WITH THE RIGHT-ENTRANCE REGION OF THE UPPER-LEVEL JET... DIMINISHING INTO THE EVENING WITH THE COLD FRONT PUSHING OFFSHORE. WITH CERTAINTY...COLD POOL WILL PUSH SOUTHEAST IMPROVING MID-LEVEL LAPSE RATES AS UNI-DIRECTIONAL SOUTHWESTERLY SHEAR INCREASES TO AROUND 30 KTS ACROSS THE REGION. SO WHILE ELEVATED INSTABILITY IS PLAUSIBLE...BOUNDARY LAYER DESTABILIZATION IS QUESTIONABLE AS ACTIVITY COULD BE ONGOING DURING THE MORNING FORCED BY STRONG LOW- LEVEL CONVERGENCE. CLOUDS IMPEDING DIURNAL HEATING. LESSER CONFIDENCE OF A SEVERE WEATHER THREAT...GREATER CONCERN FOR FLOODING WITH 2-INCH PWATS AND AFOREMENTIONED DEEP-LAYER FORCING. GREATER CHANCE FOR FLOODING ACROSS CENTRAL AND EASTERN PORTIONS OF SOUTHERN NEW ENGLAND...FOCUSING ON THE MORNING INTO MIDDAY PERIOD. */FRIDAY INTO NEXT WEEK... IT IS NOT ENTIRELY CLEAR HOW THE MID- TO UPPER-LEVEL ENERGY ASSOCIATED WITH THE ACTIVITY ON THURSDAY WILL EVOLVE. DETERMINISTIC GFS/ECMWF SOLUTIONS EXHIBIT ATTENDANT ENERGY TO BIFURCATE FROM THE NORTHERN STREAM...BECOMING A CLOSED LOW AND RETROGRADING SOUTH AND WEST WITH THE MEAN FLOW AROUND THE BROAD RIDGING ACROSS THE CONUS. QUITE ODD FOR AN EARLY SUMMERTIME PATTERN. THAT BEING SAID...SURFACE OUTCOMES REMAIN UNCERTAIN. IT APPEARS HIGH PRESSURE OUT OF THE GREAT LAKES REGION WILL USHER MORE SEASONABLE CONDITIONS BACK INTO THE REGION WITH NORTHERLY WINDS...AS A FRONTAL BOUNDARY REMAINS STALLED OFFSHORE. COULD SEE THE CHANCE OF SHOWERS FOR FAR SOUTHEAST SOUTHERN NEW ENGLAND INITIALLY. THIS HIGH WILL TRANSITION EAST RESULTING IN THE RETURN USHERANCE OF SOUTHERLY FLOW AND PERHAPS RENEWED CHANCES OF SHOWERS AND THUNDERSTORMS AS HEAT AND HUMIDITY GRADUALLY BUILD BACK OVER THE REGION. LITTLE FORCING WITHIN THE MID- TO UPPER-LEVELS IS APPARENT...SO ANY SHOWERS OUTPUTTED BY FORECAST GUIDANCE APPEARS TO BE A RESULT OF LOCALIZED CONVERGENCE LIKELY ALONG SEA-BREEZE BOUNDARIES /AIR-MASS THUNDERSTORMS/. CHANCE TO SLIGHT CHANCE POPS ACROSS THE INTERIOR... LOW CONFIDENCE SEVERE WEATHER THREATS. WILL KEEP CONDITIONS CLOSE TO SEASONABLE. && .AVIATION /20Z TUESDAY THROUGH SUNDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. .SHORT TERM...TODAY THROUGH WEDNESDAY... MODERATE CONFIDENCE ON TRENDS...LOW CONFIDENCE ON TIMING. TODAY...MVFR ACROSS MUCH OF THE REGION WITH IFR ACROSS THE CAPE. BOUNDARY IS SITUATED GENERALLY FROM KACK-KMMK-KAQW. NORTH AND EAST OF THE BOUNDARY IS IN EASTERLY TO NORTHEAST FLOW WHILE SOUTH AND WEST OF THE BOUNDARY IS DUE SOUTH. EXPECT THE CT VALLEY TO BREAK OUT INTO VFR HOWEVER EVERYWHERE ELSE SHOULD STAY SOCKED IN. VCTS CONDITIONS ARE BEST FOR PVD/BAF/BDL AS TSRA ARE FIRING ACROSS THE BOUNDARY. TONIGHT...MVFR TO IFR CONDITIONS WILL DETERIORATE TO IFR/LIFR OVERNIGHT. EASTERLY FLOW WILL SOCK THE EAST COAST IN LOW CLOUDS AND FOG. LIFR CONDITIONS ARE BEST ACROSS THE CAPE. WEDNESDAY...MAINLY MVFR/VFR CONDITIONS WITH BETTER CHANCE FOR SHOWERS/TSTMS ESPECIALLY ORH HILLS WESTWARD. WEDNESDAY NIGHT...MVFR TO IFR CONDITIONS OVERNIGHT AS SHRA AND TSRA GROW IN COVERAGE OVERNIGHT ESP ACROSS WESTERN TERMINALS. KBOS TERMINAL...MODERATE CONFIDENCE IN TAF TRENDS...LOWER IN TIMING SPECIFICS. KBDL TERMINAL...MODERATE CONFIDENCE IN TAF TRENDS...LOWER IN TIMING SPECIFICS. CONTINUED TO MENTION VCTS AS SHOWERS AND TSRA CONTINUE TO DEVELOP ALONG BOUNDARY. OUTLOOK...THURSDAY THROUGH SUNDAY...MODERATE CONFIDENCE THURSDAY INTO THURSDAY NIGHT... SHRA/TSRA...BETTER CHANCES DURING THE MORNING INTO MIDDAY HOURS PUSHING NW TO SE. MVFR/IFR CIGS WITH MVFR/IFR VSBYS...CONDITIONS POTENTIALLY LOWER WITH +RA AND ACROSS SE COASTAL TERMINALS WITH FOG. SW WINDS BACKING OUT OF THE W/NW WITH COLD FRONTAL PASSAGE. FRIDAY INTO SUNDAY... SHRA/TSRA MAY LINGER ACROSS FAR SE COASTAL TERMINALS DURING THE INITIAL PERIOD WITH MVFR-IFR IMPACTS AT LOWEST. OTHERWISE PREVAILING VFR WITH NORTHERLY WINDS. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. .SHORT TERM...HIGH CONFIDENCE. TODAY THROUGH WEDNESDAY... WINDS AND SEAS WILL REMAIN BELOW SMALL CRAFT CRITERIA THROUGH TOMORROW. AS WINDS SHIFT BACK TO S-SW AND PICK UP DURING WED AFTERNOON...WITH GUSTS UP TO 20 KT...SEAS MAY BUILD BACK UP TO AROUND 5 FT ON THE SOUTHERN WATERS. SMALL CRAFT ADV MAY BE NEEDED THEN. SEEMS THAT WNA GUIDANCE WAS OVERDOING THE SEAS AGAIN SO HAVE UNDERCUT THEM. EXPECT REDUCED VSBYS TONIGHT INTO TOMORROW MORNING FROM FOG. ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS ON WED INTO WED NIGHT. OUTLOOK...THURSDAY INTO SUNDAY...MODERATE CONFIDENCE. THURSDAY INTO THURSDAY NIGHT... RAIN AND POSSIBLE THUNDERSTORMS WILL INCREASE TOWARDS THE WATERS DURING THE DAY AND PREVAIL INTO THE EVENING ALONG AND AHEAD OF AN APPROACHING COLD FRONT. STORMS MAY BE STRONG WITH GALE FORCE GUSTS...OTHERWISE PREVAILING SW WINDS AHEAD OF THE COLD FRONT BACKING OUT OF THE W/NW LATE. SEAS IN EXCESS OF 5 FEET ON THE OUTER WATERS. VISIBILITY IMPACTS WITH HEAVY RAIN ANTICIPATED. FRIDAY INTO SUNDAY... RAIN AND POSSIBLE THUNDERSTORMS WILL LINGER FOR THE INITIAL PERIOD SLOWLY MOVING INTO THE ATLANTIC. HIGH PRESSURE BUILDING FROM THE WEST WILL RESULT IN NORTHERLY FLOW. COULD SEE GUSTS UP TO AROUND 20 KTS WHICH WOULD ALLOW SEAS ON THE OUTER WATERS TO REMAIN AT OR ABOVE 5 FEET. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...NONE. && $$ SYNOPSIS...DUNTEN/SIPPRELL NEAR TERM...DUNTEN SHORT TERM...DUNTEN LONG TERM...SIPPRELL AVIATION...DUNTEN/SIPPRELL MARINE...DUNTEN/SIPPRELL
AREA FORECAST DISCUSSION
NWS TAUNTON MA
202 PM EDT TUE JUL 9 2013 .SYNOPSIS... A FEW SHOWERS AND THUNDERSTORMS WITH LOCALLY HEAVY RAINFALL WILL AFFECT THE REGION AT TIMES THROUGH FRIDAY. AT THIS POINT...THE SHOWERS AND THUNDERSTORMS LOOK TO BE MOST WIDESPREAD ON THURSDAY. MAINLY DRY AND LESS HUMID WEATHER LOOKS FINALLY ARRIVE BY THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 200 PM UPDATE... UPDATED FORECAST TO ACCOUNT FOR CURRENT TRENDS OTHERWISE GENERALLYFORECAST REMAINS ON TRACK FOR THIS AFTERNOON. INTERESTING SET-UP ACROSS THE REGION THIS AFTERNOON. LINGERING BOUNDARY FROM YESTERDAYS BACK DOOR COLD FRONT IS STATIONED NORTH OF ACK TO MMK THEN JETS NORTHWARD ACROSS THE BERKSHIRES. THIS BOUNDARY WILL REMAINS NEARLYSTATIONARYAND WILL BE THE FOCUS ON WHERE CONVECTION WILL FIRE. TEMPERATURES NORTH OF THE BOUNDARY ARE IN THE UPPER 60S TO MID 70S...WHILE SOUTH OF THE BOUNDARY TEMPS HAVE WARMED INTO THE MID 80S. 18Z RADAR IMAGERY SHOWS A GOOD AMOUNT OF STORM COVERAGE THAT HAS DEVELOPED ALONG THIS BOUNDARY. SATELLITE IMAGERY ALSO SHOWN SOME CLEARING ALLOWING FOR SOME DIURNAL HEATING. ML CAPE VALUES ARE BETWEEN 500-1000 J/KG ACROSS RHODE ISLAND AND THE CT VALLEY. SHEAR IS NEARLY NON-EXISTENT SO THESE STORMS WILL HARDLY MOVE AND WITH PWAT VALUES NEAR 1.7 TO 2 INCHES EXPECT HEAVY DOWNPOURS WITH THESE CELLS. VERY LOCALIZED FLASH FLOODING IS THE MAIN CONCERN WITH WIND GUSTS BEING THE SECOND CONCERN. EXPECT STORMS TO CONTINUE TO FIRE OFF OF THIS BOUNDARY THROUGHOUT THE AFTERNOON HOURS. LATEST MESOSCALE MODELS ALSO SUPPORT THIS THEORY AS THE HRRR SEEMS TO BE DOING A GREAT JOB WITH ONGOING CONVECTION. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/... TONIGHT... WILL SEE LEFTOVER SCT SHOWERS/TSTMS...SOME OF WHICH WILL BE HEAVY RAINERS...THAT WILL TEND DWINDLE AFTER THE HEATING OF THE DAY. SOME MAY LINGER WEST OF THE CT RIVER AND THE E SLOPES OF THE BERKSHIRES AS K INDICES SURGE TO THE MID 30S OVERNIGHT. MAY ALSO SEE ANOTHER WEAK SHORT WAVE MOVE OUT OF N NEW ENGLAND AFTER MIDNIGHT...SO MAY RENEW CHANCE FOR PRECIP ACROSS CENTRAL AND EASTERN AREAS. WEDNESDAY... APPEARS THAT THE STALLED FRONT MAY MAKE A RUN N OF THE REGION DURING THE DAY AS WINDS SHIFT BACK TO S-SW DOWN THE COAST. LOOKS LIKE ANOTHER WAVE MOVES ALONG THIS FRONT AS WELL. THIS WILL ENHANCE CHANCES FOR PRECIP AS SURGE OF HIGHER PWATS...ON ORDER OF AROUND 2 INCHES...WORK NE INTO THE REGION. WITH THE TROPICAL CONNECTION BACK IN PLACE...WILL SEE ANOTHER ROUND OF SHOWERS/TSTMS FOR MOST AREAS THROUGH MIDDAY...THEN MAY ACTUALLY SHIFT A BIT TO THE W DURING THE AFTERNOON. CONTINUED WITH LIKELY POPS FOR SW NH/W MA/N CENTRAL CT WHERE BEST LIFT/INSTABILITY WILL REMAIN THROUGH THE DAY. TEMPS WILL ALSO SPIKE UP...EVEN WITH THE PRECIP AROUND... UPWARDS TO THE MID-UPPER 80S ACROSS THE MID AND LOWER CT VALLEY. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... HIGHLIGHTS... * A ROUND OF SHOWERS/THUNDERSTORMS LIKELY THU WITH HEAVY RAINFALL * A FEW LEFT OVER SHOWERS/STORMS MAY LINGER INTO FRI * RELIEF FROM HUMIDITY EXPECTED BY THIS WEEKEND DETAILS... WEDNESDAY NIGHT... THERE IS UNCERTAINTY ON HOW MUCH CONVECTION WILL BE ON GOING IN OUR REGION WEDNESDAY EVENING. WHILE WE MAY SEE SOME ACROSS OUR INTERIOR ZONES...THE BETTER FOCUS WILL BE TO THE WEST OF OUR REGION CLOSER TO THE SHORTWAVE/INSTABILITY AXIS. HOWEVER...WE MAY SEE AN INCREASE IN SCATTERED SHOWERS/THUNDERSTORMS DURING THE OVERNIGHT HOURS AS LOW LEVEL JET KICKS IN AHEAD OF THE SHORTWAVE. THE FAR SOUTHEAST NEW ENGLAND COAST IS OFTEN PRONE TO THIS TYPE OF ELEVATED CONVECTION AND SOME MODELS SEEM TO BE HINTING AT THIS POTENTIAL. LOCALLY HEAVY RAINFALL WOULD BE A CONCERN GIVEN HIGH PWATS IN PLACE. THURSDAY... UPPER LEVEL SHORTWAVE AND SURFACE TROUGH WILL MOVE THROUGH THE REGION ON THURSDAY. WE ARE FAIRLY CONFIDENT THAT THIS SHOULD GENERATE A ROUND OF SHOWERS AND THUNDERSTORMS ACROSS MOST OF THE REGION. THEREFORE...WILL CARRY LIKELY POPS BUT THERE IS UNCERTAINTY ON THE EXACT TIMING. THE MAIN THREAT WILL BE HEAVY RAINFALL AND LOCALIZED FLOODING. WIDESPREAD SEVERE WEATHER APPEARS UNLIKELY GIVEN A FAIR AMOUNT OF CLOUD COVER AND LIMITED 0 TO 6 KM SHEAR. HOWEVER...MID LEVEL LAPSE RATES WILL BE A LITTLE BETTER THAN RECENT DAYS SO A FEW STRONG TO SEVERE THUNDERSTORMS CAN/T BE RULED OUT. THE BULK OF THE SHOWERS AND THUNDERSTORMS WILL PROBABLY COME TO AN END DURING THURSDAY EVENING. FRIDAY... APPEARS COLD FRONT WILL HAVE MOVED TO NEAR THE COAST OR JUST OFF THE COAST BY THIS TIME. HOWEVER...UPPER TROUGH/COLD POOL ALOFT WILL STILL BE LINGERING TO THE WEST OUR REGION. THEREFORE...OPTED TO KEEP CHANCE POPS IN THE FORECAST FOR PERHAPS A FEW MORE SHOWERS AND THUNDERSTORMS BUT NOT EXPECTING THE ENTIRE DAY TO BE A WASHOUT. SATURDAY THROUGH MONDAY... UPPER TROUGH WILL HANG AROUND SOUTHERN NEW ENGLAND...BUT THERE WILL BE HIGH PRESSURE AT THE SURFACE. THEREFORE...LEANING TO MAINLY DRY WEATHER WITH SEASONABLE HIGH TEMPERATURES MAINLY IN THE 80S. WILL HAVE TO WATCH A FEW WEAK WAVES OF LOW PRESSURE PASSING TO OUR SOUTHEAST. IF THEY COME CLOSER THAN EXPECTED SOME OF OUR AREA COULD BE GRAZED BY A FEW SHOWERS...BUT FOR NOW KEEPING THE BULK OF THEM OFF THE COAST. && .AVIATION /18Z TUESDAY THROUGH SUNDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. .SHORT TERM...TODAY THROUGH WEDNESDAY... MODERATE CONFIDENCE ON TRENDS...LOW CONFIDENCE ON TIMING. TODAY...MVFR ACROSS MUCH OF THE REGION WITH IFR ACROSS THE CAPE. BOUNDARY IS SITUATED GENERALLY FROM KACK-KMMK-KAQW. NORTH AND EAST OF THE BOUNDARY IS IN EASTERLY TO NORTHEAST FLOW WHILE SOUTH AND WEST OF THE BOUNDARY IS DUE SOUTH. EXPECT THE CT VALLEY TO BREAK OUT INTO VFR HOWEVER EVERYWHERE ELSE SHOULD STAY SOCKED IN. VCTS CONDITIONS ARE BEST FOR PVD/BAF/BDL AS TSRA ARE FIRING ACROSS THE BOUNDARY. TONIGHT...MVFR TO IFR CONDITIONS WILL DETERIORATE TO IFR/LIFR OVERNIGHT. EASTERLY FLOW WILL SOCK THE EAST COAST IN LOW CLOUDS AND FOG. LIFR CONDITIONS ARE BEST ACROSS THE CAPE. WEDNESDAY...MAINLY MVFR/VFR CONDITIONS WITH BETTER CHANCE FOR SHOWERS/TSTMS ESPECIALLY ORH HILLS WESTWARD. WEDNESDAY NIGHT...MVFR TO IFR CONDITIONS OVERNIGHT AS SHRA AND TSRA GROW IN COVERAGE OVERNIGHT ESP ACROSS WESTERN TERMINALS. KBOS TERMINAL...MODERATE CONFIDENCE IN TAF TRENDS...LOWER IN TIMING SPECIFICS. KBDL TERMINAL...MODERATE CONFIDENCE IN TAF TRENDS...LOWER IN TIMING SPECIFICS. CONTINUED TO MENTION VCTS AS SHOWERS AND TSRA CONTINUE TO DEVELOP ALONG BOUNDARY. OUTLOOK...THURSDAY THROUGH SATURDAY... MODERATE CONFIDENCE. WEDNESDAY NIGHT AND THURSDAY...LOW CLOUDS/FOG PATCHES WILL LIKELY RESULT IN SOME MVFR-IFR CONDITIONS ESPECIALLY ON THE SOUTHEAST NEW ENGLAND COAST. IN ADDITION...LOWER CONDITIONS ARE ALSO EXPECTED IN SCATTERED SHOWERS AND THUNDERSTORMS WED NIGHT AND THU. ACTIVITY LOOKS MOST WIDESPREAD ON THURSDAY. FRIDAY AND SATURDAY...A FEW LINGERING SHOWERS/THUNDERSTORMS POSSIBLE ON FRIDAY. OTHERWISE...VFR CONDITIONS LIKELY DOMINATE. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. .SHORT TERM...MODERATE TO HIGH CONFIDENCE. TODAY THROUGH WEDNESDAY... WINDS AND SEAS WILL REMAIN BELOW SMALL CRAFT CRITERIA THROUGH TONIGHT. AS WINDS SHIFT BACK TO S-SW AND PICK UP DURING WED AFTERNOON...WITH GUSTS UP TO 20 KT...SEAS MAY BUILD BACK UP TO AROUND 5 FT ON THE SOUTHERN WATERS. SMALL CRAFTS MAY BE NEEDED THEN. EXPECT REDUCED VSBYS THROUGH LATE MORNING IN FOG...WITH REDEVELOPMENT TONIGHT INTO WED MORNING. THERE IS A LOW PROBABILITY FOR A CHANCE OF SHOWERS/TSTMS THIS AFTERNOON/EVENING AS WELL. OUTLOOK...WEDNESDAY NIGHT THROUGH SATURDAY... MODERATE CONFIDENCE. WEDNESDAY NIGHT AND THURSDAY... SOUTHWEST FLOW WILL CONTINUE OUT AHEAD OF A COLD FRONT. INVERSION OVER THE WATER SHOULD KEEP SEAS A BIT LOWER THAN WNA GUIDANCE SUGGESTS...BUT STILL MAY SEE SOME 5 FOOT SEAS ACROSS THE SOUTHERN WATERS AS A RESULT OF THE LONG FETCH. NEAR SHORE WIND GUSTS TO AROUND 25 KNOTS WILL ALSO BE POSSIBLE THURSDAY AFTERNOON ALONG THE SOUTH COASTAL WATERS. TWO OTHER CONCERNS WILL BE FOR AREAS OF DENSE FOG LATE WED NIGHT INTO THU MORNING ACROSS THE SOUTHERN WATERS. THERE MAY ALSO BE A A ROUND OR TWO OF THUNDERSTORMS ON THURSDAY. FRIDAY AND SATURDAY... HIGH PRESSURE WILL BUILD ACROSS THE WATERS. ANY LINGERING 5 FOOT SEAS ACROSS THE SOUTHERN WATERS SHOULD DROP BELOW SCA FRIDAY NIGHT. OTHERWISE...WINDS/SEAS SHOULD DROP BELOW SCA THRESHOLDS. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...NONE. && $$ SYNOPSIS...FRANK/EVT NEAR TERM...DUNTEN SHORT TERM...EVT LONG TERM...FRANK AVIATION...FRANK/DUNTEN MARINE...FRANK/EVT
AREA FORECAST DISCUSSION
NWS NEW YORK NY
152 PM EDT TUE JUL 9 2013 .SYNOPSIS... A WEAK FRONT ACROSS SOUTHERN CONNECTICUT WILL GRADUALLY RETURN NORTH THIS AFTERNOON. A WEAK TROUGH APPROACHES WEDNESDAY AFTERNOON...WITH A SLOWLY MOVING FRONTAL SYSTEM AFFECTING THE REGION THROUGH THE END OF THE WEEK. A COLD FRONT SLOWLY MOVES THROUGH THE REGION WEDNESDAY NIGHT THROUGH THURSDAY NIGHT...AND THEN STALLS OFFSHORE. HIGH PRESSURE THEN TRIES TO BUILD INTO THE REGION FOR THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... STALLED OUT FRONTAL BOUNDARY ACROSS SOUTHERN CT SERVING AS A TRIGGER IN AN UNCAPPED AIRMASS. THIS COMBINED WITH A LIGHT WEST FLOW ALOFT IS RAISING THE FLOOD THREAT POTENTIAL ACROSS THIS AREA. IN ADDITION...THERE IS SOME ISOLATED CONVECTION POPPING UP ALONG THE SEABREEZE FRONT ON THE NORTH SHORE OF LI. BOTH AREAS WILL BE MONITORED FOR FLOODING. LATEST HRRR MODEL TAKES BOUNDARY SLOWLY NORTH THIS AFTERNOON ALONG WITH THE CONVECTION. ADDITIONAL SCT CONVECTION WILL LIKELY FIRE UP WITH AN APPROACHING SHORT WAVE TROF TO THE NORTH AND WEST OF NYC...BEFORE DISSIPATING NEAR THE COAST EARLY THIS EVE. SEABREEZE BOUNDARY IS ALSO ANOTHER POTENTIAL TRIGGER FOR CONVECTION. DUE TO WEAK STEERING WINDS FROM THE WEST AT 10 KT OR LESS...ANY CONVECTION WILL BE CAPABLE OF BRIEF HEAVY DOWNPOURS. WIND SHEAR IS WEAK WHICH DOES NOT SUPPORT ORGANIZED SEVERE CONVECTION. VERY WARM TEMPS CONTINUE WITH DEWPOINTS INCREASING A TAD AS COMPARED TO YESTERDAY. HEAT INDICES ACROSS NYC METRO AND INTERIOR SHOULD TOP OUT IN THE LOWER 90S ONCE AGAIN. A MODERATE RISK FOR RIP CURRENTS EXISTS AT THE ATLANTIC OCEAN BEACHES OF EASTERN LONG ISLAND TODAY. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/... WEAK VORTS WILL CONTINUE TO ROTATE THROUGH THE REGION TONIGHT INTO WEDNESDAY...AS A TROUGH DIGS INTO THE GREAT LAKES. AT THE SURFACE...THE BACK DOOR FRONT WILL GRADUALLY PUSH NORTH TONIGHT INTO WEDNESDAY. ON WEDNESDAY...A PRE-FRONTAL TROUGH WILL APPROACH THE REGION IN THE AFTERNOON AHEAD OF A DEVELOPING LOW PRESSURE SYSTEM NEAR HUDSON BAY. MAIN FOCUS FOR ANY SHRA/TSRA TONIGHT SHOULD BE NORTH OF THE REGION WITH LLJ FORCING AND THE NORTHWARD MOVING FRONTAL BOUNDARY OVERNIGHT. OTHERWISE...WITH DIMINISHING INSTABILITY THIS EVENING...WOULD EXPECTED ANY CONVECTION TO GRADUALLY WEAKEN. AN ISOLATED SHRA/TSRA IS POSSIBLE OVERNIGHT WITH INCREASING LLJ...MARGINAL INSTABILITY...AND WEAK VORT ACTIVITY...BUT MAINLY DRY. INCREASINGLY MOIST SOUTHERLY FLOW WILL BRING A POTENTIAL FOR PATCHY FOG AND STRATUS OVERNIGHT. POTENTIAL INCREASES FOR MORE WIDESPREAD CONVECTION ACROSS WESTERN ZONES...BETWEEN APPROACHING PRE-FRONTAL TROUGH AND SEABREEZE BOUNDARY...WEDNESDAY AFTERNOON WITH STRENGTHENING WIND FIELDS AND APPROACHING SHORTWAVE. SEVERE POTENTIAL WILL BE PREDICATED BY AMOUNT OF SUNSHINE...BUT WITH AN INCREASINGLY MOIST AIRMASS A MODERATELY UNSTABLE AIRMASS IS QUITE POSSIBLE IN THE ABOVE MENTIONED AREA. THE OTHER THREAT WILL BE FOR HEAVY RAIN AND POTENTIAL FLASH FLOODING WITH TRAINING CELLS ALONG S/N ORIENTED BOUNDARIES AS PWATS INCREASE TO AROUND 2" AND WARM CLOUD LAYER INCREASES. VERY WARM AND INCREASINGLY HUMID CONDITIONS ON WED...WITH TEMPS IN THE MID TO UPPER 80S NYC/NJ METRO AND INTERIOR...WITH LOWER TO MID 80S ALONG THE COAST IN SOUTHERLY SYNOPTIC FLOW. && .LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/... UNSETTLED WEATHER ON TAP FOR THE MIDDLE TO THE END OF THE WEEK AS LOW PRES TRACKING ACROSS EASTERN CANADA DRAGS A COLD THROUGH THE REGION ON THURSDAY. THE FIRST ROUND OF SHOWERS AND POSSIBLE THUNDERSTORMS WILL TAPER OFF IN THE FIRST HALF OF WEDNESDAY NIGHT....AND THEN ADDITIONAL SHOWERS AND POSSIBLE THUNDERSTORMS WILL DEVELOP ON THURSDAY AS WEAK LOW PRES DEVELOPS ALONG THE FRONT AND SLIDES THROUGH THE REGION. WITH PWATS AROUND 2"...CAN EXPECT HEAVY RAIN. SCATTERED TO NUMEROUS SHOWERS/TSTMS WILL IMPACT THE REGION THROUGHOUT THE DAY...TAPERING OFF LATE. BASED ON THE MODEST SW FLOW AND BUILDING SEAS...DANGEROUS RIPS APPEAR LIKELY WED AND THU AT THE OCEAN. COLD FRONT WILL BE THROUGH THE REGION THURSDAY NIGHT AND BECOMES NEARLY STATIONARY EAST OF THE AREA. H5 TROUGH/SHORTWAVE MOVES RIGHT OVER THE AREA ON FRIDAY AND THEN STALLS OUT OVER THE AREA. EVEN THOUGH HIGH PRES BUILDS IN AT THE SFC...WILL HAVE TO KEEP AT LEAST CHANCE POPS IN THE FORECAST FOR THE WEEKEND DUE TO THIS UPPER LEVEL SYSTEM OVER THE AREA. RETURN FLOW SETS UP BRINGING AN INCREASE IN THE HEAT AND HUMIDITY AGAIN ON MON. && .AVIATION /18Z TUESDAY THROUGH SUNDAY/... VFR FORECAST INTO THIS EVENING FOR ALL SITES EXCEPT KGON. CONVECTION DEVELOPING...ISOLATED TO SCATTERED CONVECTION IS WILL PERSIST THIS AFTERNOON THROUGH 12Z WEDNESDAY...BUT CONFIDENCE IN EXACT TIMING/LOCATION NOT HIGH ENOUGH TO INCLUDE IN TAFS. VSBYS MAY DROP TO MVFR AFTER MIDNIGHT /LOW CONFIDENCE/...THEN LIFT AROUND 13Z WEDNESDAY. FIRST NIGHT OF SOUTHERLY FLOW /AS OPPOSED TO SOUTHWESTERLY/...SO MVFR CIGS ARE NOT EXPECTED...BUT WILL MONITOR TRENDS. EXCEPTION IS AT KGON WHERE IFR CIGS/VSBYS ARE FORECAST BETWEEN 09 AND 14Z WEDNESDAY...WITH MVFR CIGS/VSBYS FORECAST ON EITHER SIDE OF THAT. OCCASIONAL LIFR POSSIBLE AT KGON AROUND 12Z...BUT LOW CONFIDENCE. NY METRO ENHANCED AVIATION WEATHER SUPPORT... DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE) KEWR FCSTER COMMENTS: BEST CHANCE OF TSTMS AFTER 20Z. ANY TSTMS NEAR TERMINAL COULD CAUSE WINDS TO GO VRB BRIEFLY. KJFK FCSTER COMMENTS: BEST CHANCE OF TSTMS AFTER 20Z. ANY TSTMS NEAR TERMINAL COULD CAUSE WINDS TO GO VRB BRIEFLY. KLGA FCSTER COMMENTS: BEST CHANCE OF TSTMS AFTER 20Z. ANY TSTMS NEAR TERMINAL COULD CAUSE WINDS TO GO VRB BRIEFLY. KTEB FCSTER COMMENTS: BEST CHANCE OF TSTMS AFTER 20Z. ANY TSTMS NEAR TERMINAL COULD CAUSE WINDS TO GO VRB BRIEFLY. KHPN FCSTER COMMENTS: BEST CHANCE OF TSTMS AFTER 20Z. ANY TSTMS NEAR TERMINAL COULD CAUSE WINDS TO GO VRB BRIEFLY. KISP FCSTER COMMENTS: CONVECTION THROUGH 19Z. ADDITIONAL TSTMS POSSIBLE AFTER 19Z. ANY TSTMS NEAR TERMINAL COULD CAUSE WINDS TO GO VRB BRIEFLY. .OUTLOOK FOR 18Z WEDNESDAY THROUGH SUN... .THU-FRI...SUB VFR FOG/CIGS POSSIBLE DAILY 06Z-14Z. SCT TSTMS POSSIBLE DAILY MAINLY 18Z-04Z WITH SUB VFR POSSIBLE AT TIMES. .SAT...SUB VFR POSSIBLE IN SHOWERS. .SUN...VFR. && .MARINE... SUB SCA CONDS THROUGH TONIGHT WITH GENERAL SW WINDS EXPECTED. WINDS ARE EXPECTED TO GRADUALLY INCREASE ON WEDNESDAY AHEAD OF AN APPROACHING PRE-FRONTAL TROUGH. THERE IS POTENTIAL FOR MARGINAL SCA WINDS ACROSS WESTERN OCEAN WATERS INTO ENTRANCE OF NYC HARBOR LATE WED WITH COASTAL JET. SOUTHERLY FLOW INCREASES ON WEDNESDAY AHEAD OF A SLOWLY MOVING COLD FRONT. THIS WILL BUILD SEAS ON THE OCEAN TO SCA LEVELS BY WEDNESDAY NIGHT...AND SCA CONDITIONS WILL CONTINUE THROUGH THURSDAY. OUTSIDE OF THE S SHORE BAYS...WHERE WINDS MAY REACH SCA LEVELS...THE REMAINING WATERS SHOULD REMAIN BELOW SCA LEVELS. HIGH PRES THEN BUILDS NORTH OF THE WATERS FRIDAY THROUGH THE WEEKEND. CONDITIONS ARE THEREFORE EXPECTED TO REMAIN BELOW SCA LEVELS. && .HYDROLOGY... SCATTERED SHOWERS/THUNDERSTORMS WILL PRODUCE LOCALLY HEAVY RAIN THIS AFTERNOON. AN ISOLATED FLASH FLOOD THREAT EXISTS WITH ANY TRAINING CONVECTION...MAINLY ALONG THE WESTERN SEABREEZE BOUNDARY AND/OR BACKDOOR COLD FRONT. THE FLASH FLOOD THREAT SHOULD INCREASE A BIT ON WEDNESDAY AFTERNOON ACROSS WESTERN PORTIONS OF THE AREA...AS HEAVY RAIN ENVIRONMENT BECOMES INCREASINGLY FAVORABLE AND CONVECTIVE COVERAGE IS EXPECTED TO INCREASE BETWEEN AN APPROACHING PRE-FRONTAL TROUGH AND SEABREEZE BOUNDARY. THE THREAT FOR FLASH FLOODING WILL EXIST IN THE PATH OF ANY TRAINING THUNDERSTORMS. THUNDERSTORMS WILL BE CAPABLE OF PRODUCING LOCALLY HEAVY RAINFALL WEDNESDAY THROUGH THURSDAY NIGHT ACROSS THE HSA. ALTHOUGH WIDESPREAD FLOODING IS NOT EXPECTED AT THIS TIME...FLASH FLOODING IS POSSIBLE WITH ANY TRAINING CONVECTION. RAINFALL IN EXCESS OF 2 INCHES IS POSSIBLE IN AN AREA IF THUNDERSTORMS TRAIN OVER THAT AREA FOR AN HOUR. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...NONE. && $$
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
325 PM EDT TUE JUL 9 2013 .SYNOPSIS... 19Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS AN UNAMPLIFIED UPPER LEVEL PATTERN WITH THE MAIN NORTHERN STREAM FLOW ALIGNED ZONALLY OVER THE U.S/CANADIAN BORDER. TO THE SOUTH OF THE NORTHERN STREAM WE FIND A BROAD EXPANSE OF UPPER LEVEL RIDGING IN PLACE ACROSS MUCH OF THE SOUTHERN TIER OF THE CONUS. ONE OTHER FEATURE OF NOTE IS A TUTT FEATURE/UPPER LOW SLOWLY MIGRATING WESTWARD FROM THE BAHAMAS TOWARD THE SOUTHERN FL PENINSULA. THIS TUTT FEATURE MAY BRING SOME ENHANCED RAIN CHANCES TO THE AREA ON WEDNESDAY...ESPECIALLY FOR THE SOUTHERN HALF OF THE PENINSULA...BUT OVERALL WILL BE IN A WEAKENING PHASE IN TERMS OF ITS NEGATIVE THERMAL ANOMALY...AND THIS SHOULD LIMIT THE OVERALL POSITIVE INSTABILITY IMPACT THAT TUTT CELLS CAN HAVE TOWARD DIURNAL CONVECTION THIS TIME OF YEAR. AT THE SURFACE...HIGH PRESSURE IS ALIGNED FROM OFF THE GA/SC COAST WESTWARD ALONG OR JUST NORTH OF THE I-10 CORRIDOR. WE FIND OUR FORECAST AREA SITUATED BETWEEN THIS RIDGE AXIS AND A WEAK INVERTED TROUGH ALONG THE FL SE COAST. THIS TROUGH IS REALLY JUST THE SURFACE REFLECTION OF THE TUTT...AND IS PROGGED BY THE LATEST NAM/GFS AND LOCAL HI-RES MODELS TO MIGRATE IN ADVANCE OF THE UPPER LEVEL FEATURE ACROSS TO THE SOUTHWEST PENINSULA COAST BY THIS EVENING. THE ADDED LOW LEVEL FOCUS ASSOCIATED WITH THIS WEAK TROUGH MAY HELP TO ENHANCE THE DIURNAL THUNDERSTORM ACTIVITY FOR OUR SOUTHERN COASTAL ZONES LATER THIS AFTERNOON. .SHORT TERM (TONIGHT THROUGH THURSDAY)... REST OF THE AFTERNOON THROUGH MID EVENING... 12Z KTBW SOUNDING WAS A BIT ON THE DRY SIDE...AND WOULD NOT BE AN UNFAVORABLE PROFILE TO SUPPORT A FEW WET-MICROBURSTS WITH ANY STRONGER LATE DAY STORMS. HOWEVER...NUMERICAL GUIDANCE DOES INDICATE THAT DRIEST OF THE MID-LEVEL AIR WILL MODIFY SOMEWHAT BY THIS EVENING AND DECREASE THIS THETA-E DIFFERENCE FROM THE SURFACE. THE BEST POSITIVE MOISTURE ADVECTION WILL CERTAINLY BE DOWN TOWARD FT. MYERS. THE NET RESULT OF THIS WOULD LIKELY TO FURTHER ENHANCE THE STORM COVERAGE SOUTH OF TAMPA BAY...BUT LIMIT THE POTENTIAL WIND IMPACTS FROM ANY STRONGER STORMS. FROM TAMPA BAY NORTHWARD...THE DRIER COLUMN SHOULD KEEP THE ACTIVITY MORE SCATTERED...BUT ANY STRONGER STORMS WILL NEED TO BE WATCHED CLOSELY FOR STRONG WIND GUST POTENTIAL. TONIGHT... LINGERING EVENING STORMS WILL SHIFT OFFSHORE AND WEAKEN DURING THE MID/LATE EVENING HOURS. THE WEAK UPPER LEVEL SUPPORT FROM THE TUTT IS LIKELY TO AID ANY TYPICAL NOCTURNAL LAND BREEZE CONVECTION OVER THE WATER. HAVE INCREASED POPS AFTER MIDNIGHT AWAY FROM THE COAST INTO THE CHANCE 30-40% RANGE. JUST SOMETHING TO KEEP IN MIND FOR THOSE PLANNING TO BOAT EARLY IN THE MORNING. WEDNESDAY/WEDNESDAY NIGHT... TUTT CELL WILL STALL NEAR THE FLORIDA WEST COAST AND SLOWLY DISSIPATE. NOT EXPECTING ANY SIGNIFICANT IMPACTS FOR THIS FEATURE OTHER THAN SOME SLIGHT INCREASE IN COLUMN MOISTURE AND WEAK CYCLONIC FLOW ALOFT. COVERAGE OF SHOWERS AND STORMS IS LIKELY TO BE HIGHER ON A REGION-WIDE SCALE DURING THE AFTERNOON HOURS TOMORROW AS A RESULT OF THESE FACTORS...BUT OVERALL NOT AN OVERLY UNUSUAL WEATHER SITUATION FROM WHAT WOULD BE EXPECTED FOR JULY. THURSDAY/THURSDAY NIGHT... UPPER PATTERN WILL BEGIN TO AMPLIFY ACROSS THE EASTERN STATES. THE FL PENINSULA WILL BE ON THE BASE OF THIS TROUGH WITH ONLY LIMITED SYNOPTIC INFLUENCE. ONCE AGAIN RAIN COVERAGE WILL LIKELY BE FAIRLY HIGH ON THURSDAY AFTERNOON/EVENING...ALTHOUGH SIMILAR TO WEDNESDAY...THE TEMPORAL LENGTH OF RAINFALL AT ANY ONE LOCATION WILL LIKELY NOT BE THAT GREAT. && .LONG TERM (THURSDAY NIGHT-TUESDAY)... TROPICAL STORM CHANTAL REMAINS THE MAIN FORECAST CHALLENGE THROUGH THE LONG TERM PERIODS. THE LATEST FORECAST FROM THE NATIONAL HURRICANE CENTER CONTINUES TO SHOW THE SYSTEM MOVING NORTHWESTWARD THROUGH THE BAHAMAS LATE IN THE WEEK AND OVER THE UPCOMING WEEKEND. MODEL SOLUTIONS OFFER A VARIETY OF SOLUTIONS WITH THE 00Z GFS SHOWING THE SYSTEM TAKING A WESTWARD TRACK ACROSS CENTRAL FLORIDA EARLY NEXT WEEK...THE 00Z CANADIAN SHOWING A WELL DEFINED SYSTEM MAKING LANDFALL ACROSS SOUTHEAST GEORGIA OR SOUTHERN SOUTH CAROLINA LATE IN THE WEEKEND...WHILE THE 00Z ECMWF SHOWS NOTHING MORE THAN SOME UPPER LEVEL ENERGY SHEARING OUT OFF THE EAST COAST OF FLORIDA OVER THE UPCOMING WEEKEND. GIVEN THE FORECAST TRACK TAKING CHANTAL OVER THE HIGHER TERRAIN OF HISPANIOLA...WOULD NOT EXPECT A VERY STRONG SYSTEM TO EMERGE BACK OVER THE ATLANTIC LATE IN THE WEEK AND OVER THE UPCOMING WEEKEND...SO WILL TRY TO MAINTAIN AS MUCH FORECAST CONTINUITY AS POSSIBLE AND LEAN THE FORECAST HEAVILY IN THE DIRECTION OF THE 00Z ECMWF. AS A RESULT...WILL CONTINUE TO HIGHLIGHT A MORE TYPICAL SUMMERTIME REGIME WITH SCATTERED SHOWERS AND THUNDERSTORMS EACH DAY AND TEMPERATURES REMAINING CLOSE TO CLIMATOLOGY. && .AVIATION... ANTICIPATE SCT TSRA THIS AFTERNOON...WITH LCL MFR/LIFR PGD/FMY/RSW. TSRA REACHING LAL/TPA/PIE/SRQ WILL BE LATER AND PERHAPS MORE LIMITED...HAVE OPTED TO HOLD AT VCTS. EAST AND SE WINDS...GUSTY NEAR TSRA...SHIFTING TO ONSHORE THIS AFTERNOON AT TPA/PIE/SRQ. && .MARINE... A WEAK PRESSURE GRADIENT WILL REMAIN ACROSS MUCH OF THE EASTERN GULF OF MEXICO THROUGH THURSDAY KEEPING WINDS AND SEAS BELOW HEADLINE CRITERIA OUTSIDE OF A TYPICAL DISTRIBUTION OF SHOWERS AND STORMS. && .FIRE WEATHER... NO SIGNIFICANT FIRE WEATHER CONCERNS EXPECTED THROUGH MIDWEEK AS RELATIVE HUMIDITY VALUES REMAIN WELL ABOVE CRITICAL LEVELS. && .PRELIMINARY POINT TEMPS/POPS... TPA 74 90 76 90 / 30 50 30 50 FMY 72 92 73 91 / 30 50 30 50 GIF 72 92 73 92 / 10 50 20 50 SRQ 73 89 74 89 / 30 50 30 50 BKV 69 92 71 91 / 20 50 30 50 SPG 78 90 77 89 / 30 40 30 50 && $$ SYNOPSIS/SHORT TERM/MARINE/FIRE WX...MROCZKA LONG TERM...JELSEMA AVIATION...RUDE
AREA FORECAST DISCUSSION
NWS LINCOLN IL
215 PM CDT TUE JUL 9 2013 .DISCUSSION... ISSUED 200 PM CDT TUE JUL 9 2013 BAND OF CONVECTION THAT FIRED EARLY THIS MORNING ACROSS IOWA HAS PUSHED EAST INTO NORTH CENTRAL IL JUST AHEAD OF A MID LEVEL SHORTWAVE. UPSTREAM FROM THAT WAVE IS A MORE SIGNIFICANT SHORTWAVE OVER NORTH DAKOTA THAT WILL BRING AN END TO THE HEAT AND HUMIDITY ALONG WITH THE THREAT FOR RAIN. AT THE SURFACE...THE 18Z ANALYSIS INDICATES A WEAK OUTFLOW BOUNDARY FROM THE MORNING CONVECTION LOCATED FROM JUST WEST OF LACON AND EAST OF PEORIA AND SPRINGFIELD. THERE WAS A MIX OF SUN AND CLOUDS EARLY THIS AFTERNOON WITH TEMPERATURES CURRENTLY RANGING FROM THE UPPER 80S TO LOWER 90S WITH HEAT INDEX VALUES AROUND 100. SHORT TERM...TONIGHT THROUGH FRIDAY SEVERE STORM THREAT TONIGHT THE MAIN FORECAST CHALLENGE. WILL FOLLOW THE HRRR AND THE NCEP HI-RES ARW MODELS AS THEY HAVE SHOW A BIT MORE CONSISTENCY WITH THE DEVELOPMENT OF CONVECTION LATER THIS AFTERNOON AND ESPECIALLY TONIGHT ALONG THE SOUTHEASTWARD MOVING COLD FRONT. WILL GRADUALLY PROGRESS THE HIGHEST POPS FROM NW TO SE OVERNIGHT AS THE COLD FRONT SETTLES INTO THE REGION. FORECAST SOUNDINGS STILL CONTINUE TO SHOW AN INCREASE IN MID LEVEL WINDS CONINCIDENT WITH HIGH CAPE VALUES TONIGHT IN ADVANCE OF THE STRONGER UPPER LEVEL FORCING. AS A RESULT...A FEW OF THE STORMS WILL BE CAPABLE OF PRODUCING DAMAGING WIND GUSTS AND TORRENTIAL RAINFALL WITH PRECIP WATER VALUES AROUND 2 INCHES. ASSUMING ORGANIZED CONVECTION DOES DEVELOP TO OUR NORTHWEST THIS EVENING...THE EFFECTIVE OUTFLOW BOUNDARY SHOULD BE PRESSING SE INTO THE I-70 CORRIDOR BY MORNING WITH THE ACTUAL SYNOPTIC COLD FRONT LAGGING BEHIND. POPS WILL LOWER FROM NW TO SE TOMORROW MORNING IN ANTICIPATION OF THE COLD FRONT SLIPPING SE OF I-70 BY 21Z. MAIN QUESTION IS WHETHER ANY STORMS CAN REFIRE AHEAD OF THE FRONT TOMORROW AFTN. IF WE SEE VERY LITTLE ACTIVITY TONIGHT...CHANCES ARE WE WILL SEE STORMS REFIRE AHEAD OF THE COLD FRONT ALONG THE I-70 CORRIDOR BEFORE SHIFTING OFF TO OUR SOUTHEAST BY EVENING. IF STORMS DO ORGANIZE...AND TRACK QUICKLY SE LATE TONIGHT...WE MAY NOT SEE ANY DEVELOPMENT ACRS THE SOUTHEAST TOMORROW AFTN. STILL SOME UNCERTAINTY WITH RESPECT TO FRONTAL POSITION ACRS SE IL SO WILL CONTINUE TO KEEP POPS GOING DOWN THERE THRU THE AFTN HOURS. PACIFIC HIGH PRESSURE WILL THEN BUILD EAST INTO THE MIDWEST BRINGING IN COOLER AND LESS HUMID AIR STARTING WEDNESDAY NIGHT AND CONTINUING THRU THE REST OF THE WORK WEEK. ONE MORE HOT AND HUMID DAY FOR THE SOUTHEAST WITH TEMPERATURES RISING INTO THE LOWER 90S WITH HEAT INDEX VALUES AT OR JUST ABOVE 100. AFTER THAT... WE SHOULD AFTERNOON TEMPS DROP BACK INTO THE LOW TO MID 80S AND SURFACE DEW POINTS BACK TO THE UPPER 50S TO LOWER 60S THURSDAY AND ESPECIALLY ON FRIDAY. LONG TERM...SATURDAY THROUGH TUESDAY UPPER LEVEL RIDGING STILL FORECAST TO BUILD OVER THE CENTER OF THE NATION DURING THIS PERIOD BRINGING RELATIVELY QUIET WEATHER TO OUR AREA. STRONGER MID LEVEL FLOW WILL SHIFT WELL TO OUR NORTH WITH TEMERATURES RISING BACK INTO THE UPPER 80S TO AROUND 90 BY SUNDAY AND MONDAY. SMITH && .AVIATION... ISSUED 1245 PM CDT TUE JUL 9 2013 SATELLITE IMAGERY SHOWS SOME BREAKUP OF THE CLOUDS OVER CENTRAL IL LAST FEW HOURS...AS THE MUCAPES HAVE REACHED TO 3000. SURFACE DATA HAS SHOWN SOME BOUNDARY INTERACTION IN THE REGION MAY LATER TRIGGER CONVECTION. MOST OF CLOUDINESS OVER REGION IS MID WITH SPOTTY SCT LOW CLOUDS. KEPT TREND OF VCNTY PCPN UNTIL MAIN FRONTAL ACTIVITY APPROACHS OVERNIGHT. OVERALL...FEW CHANGES. GOETSCH && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
123 PM CDT TUE JUL 9 2013 .DISCUSSION... 1144 AM CDT FOR MORNING UPDATE... NO SIGNIFICANT CHANGES TO GOING FORECAST FOR THE MOST PART OTHER THAN REFINING POPS/WX AND TIMING OF WAVES OF SHOWERS/STORMS. AN AREA OF SHOWERS AND THUNDERSTORMS WILL CONTINUE TO SPREAD EAST ACROSS THE AREA THROUGH MIDDAY AHEAD OF A MID-LEVEL SHORT WAVE TROUGH APPROACHING THE MID/UPPER MISSISSIPPI VALLEY. AS EXPECTED... RELATIVELY WEAK MID/UPPER LEVEL FLOW RESULTING IN WEAK BULK SHEAR MAGNITUDE...WITH LOOSELY ORGANIZED MCS PRESENTING MAINLY A LOCALLY HEAVY RAIN THREAT GIVEN PWATS AROUND 2.00 INCHES. THROUGH THIS AFTERNOON...MID-LEVEL TROUGH IS PROGGED TO MOVE EAST ACROSS IL/WI...WITH ENHANCED VORTICITY/MCV OVER CENTRAL IA EXPECTED TO HELP MAINTAIN AREA OF STORMS CURRENTLY OVER EASTERN/SOUTHEAST IA. DESPITE IMPACT OF CLOUDS/SCATTERED PRECIP COVERAGE...THE COMBINATION OF INCREASING MID-LEVEL FLOW AND DEEP SHEAR ALONG WITH DIURNAL DESTABILIZATION IN WARM/MOIST AIR MASS WILL LIKELY RESULT IN AN INCREASED COVERAGE AND ORGANIZATION TO STORMS DURING LATE AFTERNOON AND EARLY EVENING HOURS...INCREASING SEVERE THREAT ALONG WITH ONGOING HEAVY RAINFALL POTENTIAL. RECENT RUNS OF RAP/HRRR SEEM TO HAVE A DECENT OVERALL HANDLE ON CURRENT ACTIVITY...AND SUPPORT THE IDEA OF THE LINE OVER EASTERN IA MOVING ACROSS THE AREA FROM MID-AFTERNOON INTO EARLY THIS EVENING. RATZER //PREV DISCUSSION... 340 AM CDT SEVERE WEATHER AND HEAVY RAIN POTENTIAL THROUGH TONIGHT WAS WHAT MUCH OF THE ANALYSIS TIME WAS SPENT ON THIS MORNING. WHAT MAINLY WAS TRYING TO DO WAS LOCK DOWN A TIMING FOR AN IMPROVED SEVERE WEATHER THREAT /MID-AFTERNOON THROUGH EARLY OVERNIGHT THOUGH AIR MASS CAN ALLOW FOR ISOLATED SEVERE ANYTIME/...AND WHAT MAIN THREATS WOULD BE /WIND AND HEAVY RAIN/. OVERALL NO MAJOR CHANGES MADE TO THE FORECAST...JUST INCREASING POPS IN THOSE MOST FAVORED TIMES...RE-ORIENTING POPS SOME...AND REFINING RAINFALL AMOUNT FORECASTS. SYNOPSIS...A VERY SOUPY AIR MASS IS ENTRENCHED IN THE REGION THIS MORNING WITH MID 70S DEW POINTS ACROSS THE FORECAST AREA AND PWATS ON LAST EVES REGIONAL RAOBS AND EARLY MORNING OBJECTIVE ANALYSIS BEING AROUND 2 INCHES. NUMEROUS SHORT WAVE IMPULSES...MANY WITH ASSOCIATED CLUSTERS OF CONVECTION...ARE FOUND UPSTREAM ACROSS THE HIGH PLAINS AND OVER THE WESTERN CORN BELT ON GOES WATER VAPOR IMAGERY. THE PRIMARY UPPER LEVEL SHORT WAVE TROUGH WILL BE DIGGING INTO EASTERN MT SOON AFTER DAYBREAK AND WILL BE THE RESPONSIBLE PARTY FOR ENDING THIS MOIST AIR MASS...AT LEAST TEMPORARILY BY LATER WED. AT THE SURFACE A FAIRLY DIFFUSE GRADIENT EXISTS EARLY TODAY WITH A WEAK STATIONARY BOUNDARY NEAR THE STATE LINE. THE WEAK FLOW HAS ALLOWED FOR LOW CLOUDS AND FOG TO BE EXPANDING THEIR WAY SOUTHWARD DOWN LAKE MI AIDED BY AMBIENT DEW POINTS EXCEEDING THE WATER TEMPS BY SEVERAL DEGREES. THE PRIMARY SURFACE FRONT IS TAKING SHAPE ACROSS THE HIGH PLAINS AND WILL DEVELOP INTO A COOL FRONT LATER TODAY AS SURFACE CYCLOGENESIS OCCURS THROUGH NORTHERN MN INTO WESTERN ONTARIO BY THIS EVE. THIS FRONT WILL MOVE INTO THE FORECAST AREA LATE TONIGHT INTO EARLY WED MORNING. MULTIPLE ROUNDS OF CONVECTION ARE LIKELY AHEAD OF THIS. MODEL PREFERENCE...THE RAP AND HRRR GUIDANCE HAVE A GOOD REPRESENTATION OF ONGOING CONVECTION. THESE HAVE THE SUPPORT OF SEVERAL OTHER CONVECTIVE ALLOWING MODELS AND HAVE BEEN GUIDED ON THROUGH MID-AFTERNOON. AFTERWORDS HAVE LEANED TOWARD THE SLIGHTLY SLOWER 09.00 NAM THAN GFS. THIS MORNING...REMNANT MCV/SHORT WAVE ENTERING WESTERN IL EARLY THIS MORNING HAS BEGUN TO INCREASE RADAR ECHOES ACROSS CENTRAL IL AND THIS TREND IS LIKELY TO CONTINUE WITH SCATTERED CONVECTION FAVORED DUE TO MODERATE TO HIGH ELEVATED INSTABILITY. NOT A PARTICULARLY STRONG LOW-LEVEL JET OR ONE WITH HUGE MOISTURE TRANSPORT THIS MORNING...DUE TO STILL BEING A GOOD DISTANCE AHEAD OF MID-LEVEL HEIGHT FALLS. SO MORNING SCATTERED TO NUMEROUS SHOWERS/STORMS ACROSS CENTRAL IL MAY STRUGGLE TO PROGRESS NORTH/NORTHEAST AT LEAST AT ANY GOOD CLIP OF SPEED. THUS ROCKFORD TO CHICAGO HAVE POPS ONLY AT THE CHANCE LEVEL...AND MORE SO BASED ON ISOLATED CELLS DEVELOPING IN THE BROAD WAA AND HIGH PWAT REGIME. WITH SUCH HIGH PWATS AS YESTERDAY MORNING SHOWED...LOCALLY HEAVY RAINFALL WOULD BE THE PRIMARILY ASPECT TO KEEP AN EYE ON WITH THESE MORNING AND EARLY AFTERNOON STORMS. AS FOR EARLY MORNING FOG/STRATUS THAT HAS BEEN DEVELOPING IN PLACES...ONSHORE FLOW MAY FAVOR PATCHES OF THIS TO CONTINUE THROUGH MID OR EVEN LATE MORNING ACROSS NORTHEAST IL AND FAR NORTHWEST IN...STUNTING A TEMPERATURE CLIMB INITIALLY. OTHERWISE THIS LOOKS LIKE IT SHOULD BEGIN DISSIPATING/RETREATING NORTH AFTER THAT TIME. CONFIDENCE...HIGH. THIS AFTERNOON THROUGH TONIGHT...THE END OF THE RAP RUN AGREES CLOSELY WITH THE NAM IN TAKING THE SHORT WAVES AND ASSOCIATED 500 AND 700MB SPEED MAXS ACROSS THE DAKOTAS AND NORTHERN NEBRASKA EARLY THIS MORNING AND TRACKING THAT EAST INTO SOUTHERN WI AND NORTHERN IL BY MID TO LATE AFTERNOON. ON THE SYNOPTIC SCALE AT THAT TIME...THE LOW-LEVEL JET AND MOISTURE TRANSPORT WILL ALSO BE ON THE EXPANSE FROM MO INTO EASTERN IA/WESTERN IL. MIXED LAYER INSTABILITY WILL BE HIGH OVER THIS AREA INCLUDING THE WESTERN FORECAST AREA GIVEN TEMPS IN THE UPPER 80S TO LOWER 90S. WHILE SOME FORM OF MCS OR MULTIPLE CLUSTERS ARE PROBABLE TO BE MOVING EASTWARD OVER SOUTHERN WI/FAR NORTHERN IL DURING THE AFTERNOON WITH THE SHORT WAVES...DEVELOPMENT IS FAVORED TO WORK ITS WAY SOUTH AND BACK TO THE SOUTHWEST FROM THERE IN THE MOIST UNSTABLE AIR MASS DURING THE MID-AFTERNOON. DEEP LAYER SHEAR IS ANTICIPATED TO BE INCREASING TO AROUND 30-35 KT BY LATE AFTERNOON WITH ORGANIZED STORMS EXPECTED TO BE ALL WORKING THEIR WAY EASTWARD. AS THE PRIMARY UPPER TROUGH APPROACHES THIS EVENING...LARGER SCALE ASCENT AND FORCING IS LIKELY TO CONTINUE REGIONAL DEVELOPMENT OF STORMS NEAR AND AHEAD OF THE SURFACE FRONT. SO WHILE THERE LOOKS TO BE TWO PRIMARY FOCUSES FOR STORMS THIS AFTERNOON INTO TONIGHT...THERE IS NOT REALLY ANTICIPATED TO BE MUCH OF A BREAK AND THE HIGH PWAT AND UNSTABLE AIR SHOULD ALLOW FOR PLENTY OF COVERAGE. THAT COVERAGE MAY INITIALLY BE A LITTLE LIMITED DEPENDING ON DEBRIS CLOUD COVER BUT IS ANTICIPATED TO BE ITS HIGHEST LATER THIS AFTERNOON THROUGH EARLY OVERNIGHT. THE MOST FAVORED MODE FOR STORMS IS MULTICELL AND SEGMENTS CAPABLE OF SCATTERED DAMAGING WINDS...ESPECIALLY AS THE STRONGER MID-LEVEL JET OVERRIDES THE FRONT THIS EVENING INTO EARLY OVERNIGHT. SOME DEVELOPMENT THIS AFTERNOON THROUGH MID-EVE HAS THE POTENTIAL TO BE SUPERCELLULAR. THE LOW-LEVEL SHEAR IS FAIRLY ANEMIC MUCH OF THIS AFTERNOON /AOB 10 KT/ BUT QUICKLY INCREASES LATE INTO EARLY THIS EVE DUE TO THE DEEPENING LOW AND INCREASING LLJ. THIS WILL HELP FAVOR COLD POOL SUSTAINABILITY AND DOES PRESENT AT LEAST SOME TORNADO THREAT...ALTHOUGH IT LOOKS LIKE SURFACE WINDS MAY BE BACKED MORE TO THE WEST OF THE FORECAST AREA IMMEDIATELY AHEAD OF A SUBTLE SECONDARY SURFACE LOW MOVING UP THE FRONT. SO THE PRIMARY THREAT WILL REMAIN WIND AND OF COURSE HEAVY RAIN WITH EXTREMELY EFFICIENT RAIN PRODUCTION WILL OCCUR IN ANY STORMS TODAY AND TONIGHT. EVEN THOUGH FORWARD PROPAGATION OF STORMS SHOULD BE ON THE INCREASE TONIGHT...SO WILL DEEP MOISTURE REPLENISHMENT AND SIMPLY PUT THE ABSOLUTE MOISTURE IS SO HIGH IT WONT TAKE MUCH TO GET HIGH RAINFALL RATES SUCH AS WE SAW YESTERDAY MORNING. THERE WILL LIKELY BE SWATHS OF RAINFALL IN EXCESS OF ONE TO TWO INCHES ACROSS THE IMMEDIATE REGION...BUT WHERE EXACTLY THEY OCCUR IS TOO CHALLENGING TO LOCK DOWN. DEBATED ON A FLASH FLOOD WATCH BUT FEEL THE THREAT IS TOO LOCALIZED AT THIS TIME FOR A WATCH. CONFIDENCE...MEDIUM. WEDNESDAY...ONGOING SCATTERED SHOWERS AND STORMS ARE POSSIBLE ACROSS MAINLY THE SOUTHERN AND EASTERN FORECAST AREA IN THE MORNING WITH STILL AT LEAST SOME HEAVY RAIN THREAT. WARM 850-925MB AIR BEHIND THE SURFACE WIND SHIFT WILL STILL FAVORED HIGHS IN THE MID TO POSSIBLY EVEN UPPER 80S IN THE SOUTH. DRIER AIR WILL GRADUALLY FILTER IN DURING THE LATER AFTERNOON AND NIGHT PER GUIDANCE. CONFIDENCE...HIGH. THURSDAY THROUGH MONDAY...PRIMARILY DRY WEATHER IS EXPECTED OVER THE AREA ALTHOUGH THE TREND IN BOTH THE EC AND GFS THEIR LAST MULTIPLE RUNS SUPPORTS WARMER TEMPERATURES THIS WEEKEND WITH MID AND MAYBE EVEN UPPER 80S SEEN. HAVE COLLABORATED AND LEANED TOWARD THE WARMER MEX GUIDANCE. THE PATTERN STILL APPEARS BLOCKED JUST WITH THE AREA MORE UNDER THE INFLUENCE OF THE UPPER RIDGE TO THE WEST. MTF && .HYDROLOGY... 410 AM CDT THE VERY MOIST AIR MASS WILL SUPPORT EFFICIENT RAINFALL PRODUCTION FROM ANY THUNDERSTORMS TODAY AND TONIGHT. THIS MAY PRESENT FLASH FLOODING ESPECIALLY ON THE LOCAL LEVEL AS OPPOSED TO ANY WIDESPREAD THREAT. THAT AND THE FACT THERE IS NOT A GREAT SET UP FOR TRUE TRAINING STORMS IS WHY NO FLASH FLOOD WATCH AT THIS TIME. HOWEVER...IF ANY STORMS ARE IN A PARTICULARLY VULNERABLE AREA...SUCH AS A METRO OR A QUICK-RESPONDING WATERSHED...IT COULD BE TROUBLE. THESE TYPE OF HIGH RATES WERE ALREADY SEEN YESTERDAY MORNING WITH A NARROW SWATH OF ONE AND A HALF TO ESTIMATED THREE PLUS INCHES OF RAIN SEEN FROM RE-FIRING STORMS IN THE WEST CHICAGO METRO. HIGH RESOLUTION MODEL GUIDANCE INDICATES SUCH SWATHS ARE PROBABLE IN THE REGION THIS AFTERNOON INTO TONIGHT ALTHOUGH WHERE IS STILL UNCERTAIN. THE GENERAL RAINFALL FORECAST IS FOR MOST AREAS TO SEE AROUND AN INCH OR A LITTLE OVER BY WEDNESDAY MORNING. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 18Z... * ANOTHER WINDOW FOR SHRA/TSRA MID/LATE AFTERNOON. * LOW CHANCE FOR SOME ADDITIONAL SHRA/TSRA OVERNIGHT. * WINDS TURNING WEST TONIGHT THEN NORTHWEST WEDNESDAY MORNING. MDB //DISCUSSION...UPDATED 18Z... FOCUS REMAINS ON SHRA/TSRA POTENTIAL THROUGH THE AFTERNOON. AN INITIAL ROUND OF SHRA/TSRA IS NOW CLEARING THE CHICAGO AREA TERMINALS. ANOTHER BAND OF SHRA AND EMBEDDED TSRA IS STRETCHED FROM RFD BACK TO FSW HAD BEEN BETTER ORGANIZED EARLIER IN THE DAY BUT HAS BEGUN TO WANE OVER THE LAST HOUR. THIS AREA IS OUT AHEAD OF AN UPPER TROUGH MOVING EASTWARD ACROSS EASTERN IOWA. A MORE FAVORABLE AIRMASS IS IN PLACE ACROSS WEST CENTRAL ILLINOIS AND IT MAY BE THAT DEVELOPMENT INCREASES IN THIS AREA WHICH MAY LARGELY STAY SOUTH OF THE TERMINALS. HOWEVER...WITH SHRA/TSRA STILL ON RADAR WILL CONTINUE TO BRING IT ACROSS THE TERMINALS THROUGH MID/LATE AFTERNOON AND THERE IS STILL SOME POTENTIAL FOR RENEWED DEVELOPMENT AS THE UPPER TROUGH APPROACHES. TOUGH CALL AND MAY NEED TO DOWNPLAY THE POTENTIAL SLIGHTLY IN THE NEXT FEW HOURS. ONCE THE WAVE PASSES LATE THIS AFTERNOON THERE LOOKS TO BE LITTLE FOCUS FOR NEW DEVELOPMENT THROUGH THE EVENING SO WILL KEEP THE TAFS DRY THOUGH A LOW CHANCE DOES EXIST FOR SOME SPOTTY DEVELOPMENT GIVEN THE UNSTABLE AIRMASS. ANOTHER WAVE CROSSES THE AREA OVERNIGHT BUT THE LOW AND MID LEVELS WILL BE DRIER SO CHANCES FOR SHRA/TSRA WILL BE LOW. WINDS OVER THE NEXT FEW HOURS WILL LIKELY BE SOMEWHAT VARIABLE BETWEEN SOUTH AND WEST THANKS TO THE SHRA/TSRA BUT EXPECT THAT ONCE THE CURRENT ACTIVITY EXITS THE CHICAGO/NW INDIANA AREA WINDS WILL TURN MORE SOUTHERLY BEFORE GOING BACK TO WEST-SOUTHWEST LATER TODAY. A FRONT WILL CROSS THE AREA WEDNESDAY MORNING SHIFTING WINDS TO THE NORTHWEST. SOME MVFR STRATOCU IS EXPECTED DURING THE MORNING BUT WOULD LIKELY LIFT TO VFR AND DIMINISH IN COVERAGE INTO THE AFTERNOON. MDB //ORD AND MDW CONFIDENCE...UPDATED 18Z... * MEDIUM-HIGH CONFIDENCE IN AT LEAST SOME SHRA/TSRA AFFECTING THE TERMINALS MID/LATE AFTERNOON...MEDIUM-HIGH CONFIDENCE IN TIMING ...LOW-MEDIUM CONFIDENCE IN COVERAGE. * MEDIUM CONFIDENCE THAT SHRA/TSRA POTENTIAL OVERNIGHT IS LOW. * HIGH CONFIDENCE IN OVERALL WIND TRENDS BUT COULD BE BRIEFLY AFFECTED BY ANY SHRA/TSRA ACTIVITY. MDB //OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z... WEDNESDAY NIGHT...VFR. THURSDAY...VFR. FRIDAY...VFR. SATURDAY...VFR. SUNDAY...VFR. MONDAY...VFR. RODRIGUEZ && .MARINE... 427 AM CDT MAIN FORECAST CONCERN IN THE NEAR TERM IS FOR AREAS ACROSS THE NORTHERN TWO THIRDS OF THE LAKE...WHERE DENSE FOG HAS SETTLED IN. EXPECT THIS FOG TO PERSIST AT LEAST THROUGH THE AFTERNOON WITH CURRENT THINKING THAT THIS FOG WILL CHURN UP WITH APPROACHING PRECIP. ALTHOUGH CONFIDENCE IS LOW...AND ITS POSSIBLE THE CURRENT DENSE FOG ADVISORY IN PLACE THROUGH THE AFTERNOON COULD NEED TO BE EXTENDED THROUGH THE EVENING. THERE IS ALSO POTENTIAL FOR THE MORE DENSE FOG TO PUSH FURTHER DOWN THE LAKE EARLY THIS MORNING...BEFORE WINDS BEGIN TO SHIFT AND BRING A STOP TO THIS SOUTHWARD MOVING AREA OF FOG. CURRENT LIGHT NORTHERLY WINDS IN PLACE ACROSS THE LAKE WILL TURN MORE SOUTHERLY THROUGHOUT TODAY AS THE NEXT SYSTEM APPROACHES FROM THE WEST. AS THIS SYSTEM THEN PROGRESSES ACROSS THE LAKE TONIGHT...EXPECT SOUTHWEST WINDS TO BECOME MORE WESTERLY WHILE INCREASING MORE TOWARDS THE 10 TO 20 KT RANGE. THEN AS HIGH PRESSURE SLOWLY BUILDS EAST TOWARDS THE LAKE...EXPECT GENERALLY NORTHERLY WINDS THROUGH THE REST OF THE WORK WEEK. RODRIGUEZ && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...DENSE FOG ADVISORY...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565- LMZ567-LMZ669-LMZ671-LMZ673-LMZ868-LMZ870-LMZ872-LMZ874 UNTIL 3 PM TUESDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1145 AM CDT TUE JUL 9 2013 .DISCUSSION... 1144 AM CDT FOR MORNING UPDATE... NO SIGNIFICANT CHANGES TO GOING FORECAST FOR THE MOST PART OTHER THAN REFINING POPS/WX AND TIMING OF WAVES OF SHOWERS/STORMS. AN AREA OF SHOWERS AND THUNDERSTORMS WILL CONTINUE TO SPREAD EAST ACROSS THE AREA THROUGH MIDDAY AHEAD OF A MID-LEVEL SHORT WAVE TROUGH APPROACHING THE MID/UPPER MISSISSIPPI VALLEY. AS EXPECTED... RELATIVELY WEAK MID/UPPER LEVEL FLOW RESULTING IN WEAK BULK SHEAR MAGNITUDE...WITH LOOSELY ORGANIZED MCS PRESENTING MAINLY A LOCALLY HEAVY RAIN THREAT GIVEN PWATS AROUND 2.00 INCHES. THROUGH THIS AFTERNOON...MID-LEVEL TROUGH IS PROGGED TO MOVE EAST ACROSS IL/WI...WITH ENHANCED VORTICITY/MCV OVER CENTRAL IA EXPECTED TO HELP MAINTAIN AREA OF STORMS CURRENTLY OVER EASTERN/SOUTHEAST IA. DESPITE IMPACT OF CLOUDS/SCATTERED PRECIP COVERAGE...THE COMBINATION OF INCREASING MID-LEVEL FLOW AND DEEP SHEAR ALONG WITH DIURNAL DESTABILIZATION IN WARM/MOIST AIR MASS WILL LIKELY RESULT IN AN INCREASED COVERAGE AND ORGANIZATION TO STORMS DURING LATE AFTERNOON AND EARLY EVENING HOURS...INCREASING SEVERE THREAT ALONG WITH ONGOING HEAVY RAINFALL POTENTIAL. RECENT RUNS OF RAP/HRRR SEEM TO HAVE A DECENT OVERALL HANDLE ON CURRENT ACTIVITY...AND SUPPORT THE IDEA OF THE LINE OVER EASTERN IA MOVING ACROSS THE AREA FROM MID-AFTERNOON INTO EARLY THIS EVENING. RATZER && .PREV DISCUSSION... 340 AM CDT SEVERE WEATHER AND HEAVY RAIN POTENTIAL THROUGH TONIGHT WAS WHAT MUCH OF THE ANALYSIS TIME WAS SPENT ON THIS MORNING. WHAT MAINLY WAS TRYING TO DO WAS LOCK DOWN A TIMING FOR AN IMPROVED SEVERE WEATHER THREAT /MID-AFTERNOON THROUGH EARLY OVERNIGHT THOUGH AIR MASS CAN ALLOW FOR ISOLATED SEVERE ANYTIME/...AND WHAT MAIN THREATS WOULD BE /WIND AND HEAVY RAIN/. OVERALL NO MAJOR CHANGES MADE TO THE FORECAST...JUST INCREASING POPS IN THOSE MOST FAVORED TIMES...RE-ORIENTING POPS SOME...AND REFINING RAINFALL AMOUNT FORECASTS. SYNOPSIS...A VERY SOUPY AIR MASS IS ENTRENCHED IN THE REGION THIS MORNING WITH MID 70S DEW POINTS ACROSS THE FORECAST AREA AND PWATS ON LAST EVES REGIONAL RAOBS AND EARLY MORNING OBJECTIVE ANALYSIS BEING AROUND 2 INCHES. NUMEROUS SHORT WAVE IMPULSES...MANY WITH ASSOCIATED CLUSTERS OF CONVECTION...ARE FOUND UPSTREAM ACROSS THE HIGH PLAINS AND OVER THE WESTERN CORN BELT ON GOES WATER VAPOR IMAGERY. THE PRIMARY UPPER LEVEL SHORT WAVE TROUGH WILL BE DIGGING INTO EASTERN MT SOON AFTER DAYBREAK AND WILL BE THE RESPONSIBLE PARTY FOR ENDING THIS MOIST AIR MASS...AT LEAST TEMPORARILY BY LATER WED. AT THE SURFACE A FAIRLY DIFFUSE GRADIENT EXISTS EARLY TODAY WITH A WEAK STATIONARY BOUNDARY NEAR THE STATE LINE. THE WEAK FLOW HAS ALLOWED FOR LOW CLOUDS AND FOG TO BE EXPANDING THEIR WAY SOUTHWARD DOWN LAKE MI AIDED BY AMBIENT DEW POINTS EXCEEDING THE WATER TEMPS BY SEVERAL DEGREES. THE PRIMARY SURFACE FRONT IS TAKING SHAPE ACROSS THE HIGH PLAINS AND WILL DEVELOP INTO A COOL FRONT LATER TODAY AS SURFACE CYCLOGENESIS OCCURS THROUGH NORTHERN MN INTO WESTERN ONTARIO BY THIS EVE. THIS FRONT WILL MOVE INTO THE FORECAST AREA LATE TONIGHT INTO EARLY WED MORNING. MULTIPLE ROUNDS OF CONVECTION ARE LIKELY AHEAD OF THIS. MODEL PREFERENCE...THE RAP AND HRRR GUIDANCE HAVE A GOOD REPRESENTATION OF ONGOING CONVECTION. THESE HAVE THE SUPPORT OF SEVERAL OTHER CONVECTIVE ALLOWING MODELS AND HAVE BEEN GUIDED ON THROUGH MID-AFTERNOON. AFTERWORDS HAVE LEANED TOWARD THE SLIGHTLY SLOWER 09.00 NAM THAN GFS. THIS MORNING...REMNANT MCV/SHORT WAVE ENTERING WESTERN IL EARLY THIS MORNING HAS BEGUN TO INCREASE RADAR ECHOES ACROSS CENTRAL IL AND THIS TREND IS LIKELY TO CONTINUE WITH SCATTERED CONVECTION FAVORED DUE TO MODERATE TO HIGH ELEVATED INSTABILITY. NOT A PARTICULARLY STRONG LOW-LEVEL JET OR ONE WITH HUGE MOISTURE TRANSPORT THIS MORNING...DUE TO STILL BEING A GOOD DISTANCE AHEAD OF MID-LEVEL HEIGHT FALLS. SO MORNING SCATTERED TO NUMEROUS SHOWERS/STORMS ACROSS CENTRAL IL MAY STRUGGLE TO PROGRESS NORTH/NORTHEAST AT LEAST AT ANY GOOD CLIP OF SPEED. THUS ROCKFORD TO CHICAGO HAVE POPS ONLY AT THE CHANCE LEVEL...AND MORE SO BASED ON ISOLATED CELLS DEVELOPING IN THE BROAD WAA AND HIGH PWAT REGIME. WITH SUCH HIGH PWATS AS YESTERDAY MORNING SHOWED...LOCALLY HEAVY RAINFALL WOULD BE THE PRIMARILY ASPECT TO KEEP AN EYE ON WITH THESE MORNING AND EARLY AFTERNOON STORMS. AS FOR EARLY MORNING FOG/STRATUS THAT HAS BEEN DEVELOPING IN PLACES...ONSHORE FLOW MAY FAVOR PATCHES OF THIS TO CONTINUE THROUGH MID OR EVEN LATE MORNING ACROSS NORTHEAST IL AND FAR NORTHWEST IN...STUNTING A TEMPERATURE CLIMB INITIALLY. OTHERWISE THIS LOOKS LIKE IT SHOULD BEGIN DISSIPATING/RETREATING NORTH AFTER THAT TIME. CONFIDENCE...HIGH. THIS AFTERNOON THROUGH TONIGHT...THE END OF THE RAP RUN AGREES CLOSELY WITH THE NAM IN TAKING THE SHORT WAVES AND ASSOCIATED 500 AND 700MB SPEED MAXS ACROSS THE DAKOTAS AND NORTHERN NEBRASKA EARLY THIS MORNING AND TRACKING THAT EAST INTO SOUTHERN WI AND NORTHERN IL BY MID TO LATE AFTERNOON. ON THE SYNOPTIC SCALE AT THAT TIME...THE LOW-LEVEL JET AND MOISTURE TRANSPORT WILL ALSO BE ON THE EXPANSE FROM MO INTO EASTERN IA/WESTERN IL. MIXED LAYER INSTABILITY WILL BE HIGH OVER THIS AREA INCLUDING THE WESTERN FORECAST AREA GIVEN TEMPS IN THE UPPER 80S TO LOWER 90S. WHILE SOME FORM OF MCS OR MULTIPLE CLUSTERS ARE PROBABLE TO BE MOVING EASTWARD OVER SOUTHERN WI/FAR NORTHERN IL DURING THE AFTERNOON WITH THE SHORT WAVES...DEVELOPMENT IS FAVORED TO WORK ITS WAY SOUTH AND BACK TO THE SOUTHWEST FROM THERE IN THE MOIST UNSTABLE AIR MASS DURING THE MID-AFTERNOON. DEEP LAYER SHEAR IS ANTICIPATED TO BE INCREASING TO AROUND 30-35 KT BY LATE AFTERNOON WITH ORGANIZED STORMS EXPECTED TO BE ALL WORKING THEIR WAY EASTWARD. AS THE PRIMARY UPPER TROUGH APPROACHES THIS EVENING...LARGER SCALE ASCENT AND FORCING IS LIKELY TO CONTINUE REGIONAL DEVELOPMENT OF STORMS NEAR AND AHEAD OF THE SURFACE FRONT. SO WHILE THERE LOOKS TO BE TWO PRIMARY FOCUSES FOR STORMS THIS AFTERNOON INTO TONIGHT...THERE IS NOT REALLY ANTICIPATED TO BE MUCH OF A BREAK AND THE HIGH PWAT AND UNSTABLE AIR SHOULD ALLOW FOR PLENTY OF COVERAGE. THAT COVERAGE MAY INITIALLY BE A LITTLE LIMITED DEPENDING ON DEBRIS CLOUD COVER BUT IS ANTICIPATED TO BE ITS HIGHEST LATER THIS AFTERNOON THROUGH EARLY OVERNIGHT. THE MOST FAVORED MODE FOR STORMS IS MULTICELL AND SEGMENTS CAPABLE OF SCATTERED DAMAGING WINDS...ESPECIALLY AS THE STRONGER MID-LEVEL JET OVERRIDES THE FRONT THIS EVENING INTO EARLY OVERNIGHT. SOME DEVELOPMENT THIS AFTERNOON THROUGH MID-EVE HAS THE POTENTIAL TO BE SUPERCELLULAR. THE LOW-LEVEL SHEAR IS FAIRLY ANEMIC MUCH OF THIS AFTERNOON /AOB 10 KT/ BUT QUICKLY INCREASES LATE INTO EARLY THIS EVE DUE TO THE DEEPENING LOW AND INCREASING LLJ. THIS WILL HELP FAVOR COLD POOL SUSTAINABILITY AND DOES PRESENT AT LEAST SOME TORNADO THREAT...ALTHOUGH IT LOOKS LIKE SURFACE WINDS MAY BE BACKED MORE TO THE WEST OF THE FORECAST AREA IMMEDIATELY AHEAD OF A SUBTLE SECONDARY SURFACE LOW MOVING UP THE FRONT. SO THE PRIMARY THREAT WILL REMAIN WIND AND OF COURSE HEAVY RAIN WITH EXTREMELY EFFICIENT RAIN PRODUCTION WILL OCCUR IN ANY STORMS TODAY AND TONIGHT. EVEN THOUGH FORWARD PROPAGATION OF STORMS SHOULD BE ON THE INCREASE TONIGHT...SO WILL DEEP MOISTURE REPLENISHMENT AND SIMPLY PUT THE ABSOLUTE MOISTURE IS SO HIGH IT WONT TAKE MUCH TO GET HIGH RAINFALL RATES SUCH AS WE SAW YESTERDAY MORNING. THERE WILL LIKELY BE SWATHS OF RAINFALL IN EXCESS OF ONE TO TWO INCHES ACROSS THE IMMEDIATE REGION...BUT WHERE EXACTLY THEY OCCUR IS TOO CHALLENGING TO LOCK DOWN. DEBATED ON A FLASH FLOOD WATCH BUT FEEL THE THREAT IS TOO LOCALIZED AT THIS TIME FOR A WATCH. CONFIDENCE...MEDIUM. WEDNESDAY...ONGOING SCATTERED SHOWERS AND STORMS ARE POSSIBLE ACROSS MAINLY THE SOUTHERN AND EASTERN FORECAST AREA IN THE MORNING WITH STILL AT LEAST SOME HEAVY RAIN THREAT. WARM 850-925MB AIR BEHIND THE SURFACE WIND SHIFT WILL STILL FAVORED HIGHS IN THE MID TO POSSIBLY EVEN UPPER 80S IN THE SOUTH. DRIER AIR WILL GRADUALLY FILTER IN DURING THE LATER AFTERNOON AND NIGHT PER GUIDANCE. CONFIDENCE...HIGH. THURSDAY THROUGH MONDAY...PRIMARILY DRY WEATHER IS EXPECTED OVER THE AREA ALTHOUGH THE TREND IN BOTH THE EC AND GFS THEIR LAST MULTIPLE RUNS SUPPORTS WARMER TEMPERATURES THIS WEEKEND WITH MID AND MAYBE EVEN UPPER 80S SEEN. HAVE COLLABORATED AND LEANED TOWARD THE WARMER MEX GUIDANCE. THE PATTERN STILL APPEARS BLOCKED JUST WITH THE AREA MORE UNDER THE INFLUENCE OF THE UPPER RIDGE TO THE WEST. MTF && .HYDROLOGY... 410 AM CDT THE VERY MOIST AIR MASS WILL SUPPORT EFFICIENT RAINFALL PRODUCTION FROM ANY THUNDERSTORMS TODAY AND TONIGHT. THIS MAY PRESENT FLASH FLOODING ESPECIALLY ON THE LOCAL LEVEL AS OPPOSED TO ANY WIDESPREAD THREAT. THAT AND THE FACT THERE IS NOT A GREAT SET UP FOR TRUE TRAINING STORMS IS WHY NO FLASH FLOOD WATCH AT THIS TIME. HOWEVER...IF ANY STORMS ARE IN A PARTICULARLY VULNERABLE AREA...SUCH AS A METRO OR A QUICK-RESPONDING WATERSHED...IT COULD BE TROUBLE. THESE TYPE OF HIGH RATES WERE ALREADY SEEN YESTERDAY MORNING WITH A NARROW SWATH OF ONE AND A HALF TO ESTIMATED THREE PLUS INCHES OF RAIN SEEN FROM RE-FIRING STORMS IN THE WEST CHICAGO METRO. HIGH RESOLUTION MODEL GUIDANCE INDICATES SUCH SWATHS ARE PROBABLE IN THE REGION THIS AFTERNOON INTO TONIGHT ALTHOUGH WHERE IS STILL UNCERTAIN. THE GENERAL RAINFALL FORECAST IS FOR MOST AREAS TO SEE AROUND AN INCH OR A LITTLE OVER BY WEDNESDAY MORNING. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 16Z... * ONE BAND OF SCATTERED TSRA EXPECTED BETWEEN 17-19Z...VERY BRIEF IFR VSBY POSSIBLE. * NEXT ROUND OF TSRA EXPECTED LATE TOWARD 20/21Z FROM THE WEST...BETTER ORGANIZATION AND LOWER VSBY IS MORE LIKELY WITH THIS ROUND. * SOME CHANCE OF ADDITIONAL SHRA/TSRA LATE TONIGHT OR EARLY WEDNESDAY MORNING. MDB //DISCUSSION...UPDATED 16Z... CONVECTIVE POTENTIAL STARTING TO BECOME A BIT MORE CLEAR. ONE CLUSTER OF SHRA/TSRA CONTINUES TO APPROACH FROM THE WEST WITH FLUCTUATIONS IN INTENSITY AND COVERAGE. INDIVIDUAL TS CELLS ARE PRETTY SMALL BUT CONTINUE TO POP SO WILL CARRY VCTS AND A PERIOD OF TEMPO TS AT THE TERMINALS OVER THE NEXT FEW HOURS...THOUGH COVERAGE MAY BEGIN TO WANE. VERY BRIEF IFR VSBY IS POSSIBLE UNDER THE HEAVIER CELLS. THE NEXT ROUND OF STORMS IS TAKING SHAPE ACROSS EASTERN AND SOUTH CENTRAL IOWA WHICH WOULD ARRIVE IN THE AREA MID TO LATE AFTERNOON. THERE SHOULD BE SHORT BREAK IN TS BEHIND THE INITIAL AREA BEFORE THIS NEXT AREA ARRIVES. THIS SECOND AREA WILL LIKELY BE MORE WIDESPREAD IN COVERAGE WITH LONGER PERIODS OF LOW VISIBILITY POSSIBLE...ALONG WITH THE POTENTIAL FOR GUSTY WINDS. THIS ALSO POINTS TO THE EVENING HOURS BEING QUIET SO WILL NEED TO RE-EVALUATE SHRA/TSRA MENTION THEN. MDB FROM 12Z... RELATIVELY QUIET ACROSS THE TERMINALS THIS MORNING WHILE SOME FOG/HAZE REMAINS OVERHEAD...BUT WITH THE MORE DENSE FOG REMAINING AWAY FROM THE TERMINALS AT THIS TIME. ANY FOG THIS MORNING SHOULD QUICKLY DISSIPATE OVER THE NEXT HOUR WITH ANY THREAT OF LOWER VIS/CEILINGS COMING SOUTH DOWN THE LAKE REMAINING LOW AT THIS TIME. ALTHOUGH THIS AREA IS STILL SLOWLY MOVING SOUTH DOWN THE LAKE...VEERING WINDS AND SHOULD HELP LIMIT THIS SOUTHWARD MOMENTUM KEEPING THIS FOG NORTH OF THE TERMINALS. THEN SHIFT GEARS TO REDEVELOPMENT OF SHOWERS/TS LATER THIS MORNING...AS PRECIP DEVELOPS OUT AHEAD OF AN APPROACHING MID LEVEL DISTURBANCE. AS THIS DISTURBANCE DRAWS NEAR...EXPECT CURRENT THUNDERSTORMS OVER IOWA AS WELL AS OTHER DEVELOPMENT TO MOVE ACROSS THROUGH NORTHERN ILLINOIS/NORTHWEST INDIANA BY MID DAY WITH SOME UPWARD GROWTH IN COVERAGE AND INTENSITY EXPECTED INTO THE EARLY AFTERNOON. DO EXPECT A BRIEF LULL IN THE ACTIVITY AFTER THIS INITIAL PRECIP MOVES THROUGH...BUT WITH DEVELOPMENT STILL POSSIBLE GOING INTO THE EARLY EVENING. STILL MONITORING THE POTENTIAL FOR A MORE WIDESPREAD AREA OF THUNDERSTORMS TO MOVE ACROSS THE TERMINALS LATER THIS EVENING AND OVERNIGHT. ALTHOUGH IT STILL SEEMS FAVORABLE FOR THIS TO MOVE ACROSS THE TERMINALS...WILL NEED TO MONITOR LATER TRENDS AFTER THIS INITIAL PRECIP THIS AFTERNOON MOVES THROUGH. WINDS REMAIN LIGHT/VARIABLE THIS MORNING BUT ANTICIPATE A TREND TOWARDS AN EAST NORTHEAST WIND OVER THE NEXT SEVERAL HOURS. WINDS ALONG THE LAKE ARE ALREADY THIS EASTERLY COMPONENT AND WITH THE SUN RISING COINCIDING WITH A WEAK GRADIENT...FEEL THAT IT WONT TAKE MUCH FOR THIS NORTHEAST WIND TO DEVELOP OVER ORD/MDW/GYY THIS MORNING. THEN EXPECT A SLOW TREND TOWARDS THE SOUTHEAST AND EVENTUALLY SOUTH THIS AFTERNOON/EVENING...BEFORE WINDS CONTINUE TO VEER TO THE WEST OVERNIGHT. RODRIGUEZ //ORD AND MDW CONFIDENCE...UPDATED 16Z... * HIGH CONFIDENCE IN BAND OF SHRA/TSRA 17-19Z...MAY BE FAIRLY SCATTERED THOUGH...HIGH CONFIDENCE THAT ANY IFR VSBY WOULD BE BRIEF. * MEDIUM-HIGH CONFIDENCE IN ADDITIONAL ACTIVITY ARRIVING LATER THIS AFTERNOON AND IT WOULD BE MORE WIDESPREAD AND INTENSE...MEDIUM CONFIDENCE IN TIMING. * LOW CONFIDENCE IN POTENTIAL FOR ADDITIONAL ACTIVITY TONIGHT/WEDNESDAY MORNING. MDB //OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z... WEDNESDAY NIGHT...VFR. THURSDAY...VFR. FRIDAY...VFR. SATURDAY...VFR. SUNDAY...VFR. MONDAY...VFR. RODRIGUEZ && .MARINE... 427 AM CDT MAIN FORECAST CONCERN IN THE NEAR TERM IS FOR AREAS ACROSS THE NORTHERN TWO THIRDS OF THE LAKE...WHERE DENSE FOG HAS SETTLED IN. EXPECT THIS FOG TO PERSIST AT LEAST THROUGH THE AFTERNOON WITH CURRENT THINKING THAT THIS FOG WILL CHURN UP WITH APPROACHING PRECIP. ALTHOUGH CONFIDENCE IS LOW...AND ITS POSSIBLE THE CURRENT DENSE FOG ADVISORY IN PLACE THROUGH THE AFTERNOON COULD NEED TO BE EXTENDED THROUGH THE EVENING. THERE IS ALSO POTENTIAL FOR THE MORE DENSE FOG TO PUSH FURTHER DOWN THE LAKE EARLY THIS MORNING...BEFORE WINDS BEGIN TO SHIFT AND BRING A STOP TO THIS SOUTHWARD MOVING AREA OF FOG. CURRENT LIGHT NORTHERLY WINDS IN PLACE ACROSS THE LAKE WILL TURN MORE SOUTHERLY THROUGHOUT TODAY AS THE NEXT SYSTEM APPROACHES FROM THE WEST. AS THIS SYSTEM THEN PROGRESSES ACROSS THE LAKE TONIGHT...EXPECT SOUTHWEST WINDS TO BECOME MORE WESTERLY WHILE INCREASING MORE TOWARDS THE 10 TO 20 KT RANGE. THEN AS HIGH PRESSURE SLOWLY BUILDS EAST TOWARDS THE LAKE...EXPECT GENERALLY NORTHERLY WINDS THROUGH THE REST OF THE WORK WEEK. RODRIGUEZ && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...DENSE FOG ADVISORY...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565- LMZ567-LMZ669-LMZ671-LMZ673-LMZ868-LMZ870-LMZ872-LMZ874 UNTIL 3 PM TUESDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1115 AM CDT TUE JUL 9 2013 .DISCUSSION... 340 AM CDT SEVERE WEATHER AND HEAVY RAIN POTENTIAL THROUGH TONIGHT WAS WHAT MUCH OF THE ANALYSIS TIME WAS SPENT ON THIS MORNING. WHAT MAINLY WAS TRYING TO DO WAS LOCK DOWN A TIMING FOR AN IMPROVED SEVERE WEATHER THREAT /MID-AFTERNOON THROUGH EARLY OVERNIGHT THOUGH AIR MASS CAN ALLOW FOR ISOLATED SEVERE ANYTIME/...AND WHAT MAIN THREATS WOULD BE /WIND AND HEAVY RAIN/. OVERALL NO MAJOR CHANGES MADE TO THE FORECAST...JUST INCREASING POPS IN THOSE MOST FAVORED TIMES...RE-ORIENTING POPS SOME...AND REFINING RAINFALL AMOUNT FORECASTS. SYNOPSIS...A VERY SOUPY AIR MASS IS ENTRENCHED IN THE REGION THIS MORNING WITH MID 70S DEW POINTS ACROSS THE FORECAST AREA AND PWATS ON LAST EVES REGIONAL RAOBS AND EARLY MORNING OBJECTIVE ANALYSIS BEING AROUND 2 INCHES. NUMEROUS SHORT WAVE IMPULSES...MANY WITH ASSOCIATED CLUSTERS OF CONVECTION...ARE FOUND UPSTREAM ACROSS THE HIGH PLAINS AND OVER THE WESTERN CORN BELT ON GOES WATER VAPOR IMAGERY. THE PRIMARY UPPER LEVEL SHORT WAVE TROUGH WILL BE DIGGING INTO EASTERN MT SOON AFTER DAYBREAK AND WILL BE THE RESPONSIBLE PARTY FOR ENDING THIS MOIST AIR MASS...AT LEAST TEMPORARILY BY LATER WED. AT THE SURFACE A FAIRLY DIFFUSE GRADIENT EXISTS EARLY TODAY WITH A WEAK STATIONARY BOUNDARY NEAR THE STATE LINE. THE WEAK FLOW HAS ALLOWED FOR LOW CLOUDS AND FOG TO BE EXPANDING THEIR WAY SOUTHWARD DOWN LAKE MI AIDED BY AMBIENT DEW POINTS EXCEEDING THE WATER TEMPS BY SEVERAL DEGREES. THE PRIMARY SURFACE FRONT IS TAKING SHAPE ACROSS THE HIGH PLAINS AND WILL DEVELOP INTO A COOL FRONT LATER TODAY AS SURFACE CYCLOGENESIS OCCURS THROUGH NORTHERN MN INTO WESTERN ONTARIO BY THIS EVE. THIS FRONT WILL MOVE INTO THE FORECAST AREA LATE TONIGHT INTO EARLY WED MORNING. MULTIPLE ROUNDS OF CONVECTION ARE LIKELY AHEAD OF THIS. MODEL PREFERENCE...THE RAP AND HRRR GUIDANCE HAVE A GOOD REPRESENTATION OF ONGOING CONVECTION. THESE HAVE THE SUPPORT OF SEVERAL OTHER CONVECTIVE ALLOWING MODELS AND HAVE BEEN GUIDED ON THROUGH MID-AFTERNOON. AFTERWORDS HAVE LEANED TOWARD THE SLIGHTLY SLOWER 09.00 NAM THAN GFS. THIS MORNING...REMNANT MCV/SHORT WAVE ENTERING WESTERN IL EARLY THIS MORNING HAS BEGUN TO INCREASE RADAR ECHOES ACROSS CENTRAL IL AND THIS TREND IS LIKELY TO CONTINUE WITH SCATTERED CONVECTION FAVORED DUE TO MODERATE TO HIGH ELEVATED INSTABILITY. NOT A PARTICULARLY STRONG LOW-LEVEL JET OR ONE WITH HUGE MOISTURE TRANSPORT THIS MORNING...DUE TO STILL BEING A GOOD DISTANCE AHEAD OF MID-LEVEL HEIGHT FALLS. SO MORNING SCATTERED TO NUMEROUS SHOWERS/STORMS ACROSS CENTRAL IL MAY STRUGGLE TO PROGRESS NORTH/NORTHEAST AT LEAST AT ANY GOOD CLIP OF SPEED. THUS ROCKFORD TO CHICAGO HAVE POPS ONLY AT THE CHANCE LEVEL...AND MORE SO BASED ON ISOLATED CELLS DEVELOPING IN THE BROAD WAA AND HIGH PWAT REGIME. WITH SUCH HIGH PWATS AS YESTERDAY MORNING SHOWED...LOCALLY HEAVY RAINFALL WOULD BE THE PRIMARILY ASPECT TO KEEP AN EYE ON WITH THESE MORNING AND EARLY AFTERNOON STORMS. AS FOR EARLY MORNING FOG/STRATUS THAT HAS BEEN DEVELOPING IN PLACES...ONSHORE FLOW MAY FAVOR PATCHES OF THIS TO CONTINUE THROUGH MID OR EVEN LATE MORNING ACROSS NORTHEAST IL AND FAR NORTHWEST IN...STUNTING A TEMPERATURE CLIMB INITIALLY. OTHERWISE THIS LOOKS LIKE IT SHOULD BEGIN DISSIPATING/RETREATING NORTH AFTER THAT TIME. CONFIDENCE...HIGH. THIS AFTERNOON THROUGH TONIGHT...THE END OF THE RAP RUN AGREES CLOSELY WITH THE NAM IN TAKING THE SHORT WAVES AND ASSOCIATED 500 AND 700MB SPEED MAXS ACROSS THE DAKOTAS AND NORTHERN NEBRASKA EARLY THIS MORNING AND TRACKING THAT EAST INTO SOUTHERN WI AND NORTHERN IL BY MID TO LATE AFTERNOON. ON THE SYNOPTIC SCALE AT THAT TIME...THE LOW-LEVEL JET AND MOISTURE TRANSPORT WILL ALSO BE ON THE EXPANSE FROM MO INTO EASTERN IA/WESTERN IL. MIXED LAYER INSTABILITY WILL BE HIGH OVER THIS AREA INCLUDING THE WESTERN FORECAST AREA GIVEN TEMPS IN THE UPPER 80S TO LOWER 90S. WHILE SOME FORM OF MCS OR MULTIPLE CLUSTERS ARE PROBABLE TO BE MOVING EASTWARD OVER SOUTHERN WI/FAR NORTHERN IL DURING THE AFTERNOON WITH THE SHORT WAVES...DEVELOPMENT IS FAVORED TO WORK ITS WAY SOUTH AND BACK TO THE SOUTHWEST FROM THERE IN THE MOIST UNSTABLE AIR MASS DURING THE MID-AFTERNOON. DEEP LAYER SHEAR IS ANTICIPATED TO BE INCREASING TO AROUND 30-35 KT BY LATE AFTERNOON WITH ORGANIZED STORMS EXPECTED TO BE ALL WORKING THEIR WAY EASTWARD. AS THE PRIMARY UPPER TROUGH APPROACHES THIS EVENING...LARGER SCALE ASCENT AND FORCING IS LIKELY TO CONTINUE REGIONAL DEVELOPMENT OF STORMS NEAR AND AHEAD OF THE SURFACE FRONT. SO WHILE THERE LOOKS TO BE TWO PRIMARY FOCUSES FOR STORMS THIS AFTERNOON INTO TONIGHT...THERE IS NOT REALLY ANTICIPATED TO BE MUCH OF A BREAK AND THE HIGH PWAT AND UNSTABLE AIR SHOULD ALLOW FOR PLENTY OF COVERAGE. THAT COVERAGE MAY INITIALLY BE A LITTLE LIMITED DEPENDING ON DEBRIS CLOUD COVER BUT IS ANTICIPATED TO BE ITS HIGHEST LATER THIS AFTERNOON THROUGH EARLY OVERNIGHT. THE MOST FAVORED MODE FOR STORMS IS MULTICELL AND SEGMENTS CAPABLE OF SCATTERED DAMAGING WINDS...ESPECIALLY AS THE STRONGER MID-LEVEL JET OVERRIDES THE FRONT THIS EVENING INTO EARLY OVERNIGHT. SOME DEVELOPMENT THIS AFTERNOON THROUGH MID-EVE HAS THE POTENTIAL TO BE SUPERCELLULAR. THE LOW-LEVEL SHEAR IS FAIRLY ANEMIC MUCH OF THIS AFTERNOON /AOB 10 KT/ BUT QUICKLY INCREASES LATE INTO EARLY THIS EVE DUE TO THE DEEPENING LOW AND INCREASING LLJ. THIS WILL HELP FAVOR COLD POOL SUSTAINABILITY AND DOES PRESENT AT LEAST SOME TORNADO THREAT...ALTHOUGH IT LOOKS LIKE SURFACE WINDS MAY BE BACKED MORE TO THE WEST OF THE FORECAST AREA IMMEDIATELY AHEAD OF A SUBTLE SECONDARY SURFACE LOW MOVING UP THE FRONT. SO THE PRIMARY THREAT WILL REMAIN WIND AND OF COURSE HEAVY RAIN WITH EXTREMELY EFFICIENT RAIN PRODUCTION WILL OCCUR IN ANY STORMS TODAY AND TONIGHT. EVEN THOUGH FORWARD PROPAGATION OF STORMS SHOULD BE ON THE INCREASE TONIGHT...SO WILL DEEP MOISTURE REPLENISHMENT AND SIMPLY PUT THE ABSOLUTE MOISTURE IS SO HIGH IT WONT TAKE MUCH TO GET HIGH RAINFALL RATES SUCH AS WE SAW YESTERDAY MORNING. THERE WILL LIKELY BE SWATHS OF RAINFALL IN EXCESS OF ONE TO TWO INCHES ACROSS THE IMMEDIATE REGION...BUT WHERE EXACTLY THEY OCCUR IS TOO CHALLENGING TO LOCK DOWN. DEBATED ON A FLASH FLOOD WATCH BUT FEEL THE THREAT IS TOO LOCALIZED AT THIS TIME FOR A WATCH. CONFIDENCE...MEDIUM. WEDNESDAY...ONGOING SCATTERED SHOWERS AND STORMS ARE POSSIBLE ACROSS MAINLY THE SOUTHERN AND EASTERN FORECAST AREA IN THE MORNING WITH STILL AT LEAST SOME HEAVY RAIN THREAT. WARM 850-925MB AIR BEHIND THE SURFACE WIND SHIFT WILL STILL FAVORED HIGHS IN THE MID TO POSSIBLY EVEN UPPER 80S IN THE SOUTH. DRIER AIR WILL GRADUALLY FILTER IN DURING THE LATER AFTERNOON AND NIGHT PER GUIDANCE. CONFIDENCE...HIGH. THURSDAY THROUGH MONDAY...PRIMARILY DRY WEATHER IS EXPECTED OVER THE AREA ALTHOUGH THE TREND IN BOTH THE EC AND GFS THEIR LAST MULTIPLE RUNS SUPPORTS WARMER TEMPERATURES THIS WEEKEND WITH MID AND MAYBE EVEN UPPER 80S SEEN. HAVE COLLABORATED AND LEANED TOWARD THE WARMER MEX GUIDANCE. THE PATTERN STILL APPEARS BLOCKED JUST WITH THE AREA MORE UNDER THE INFLUENCE OF THE UPPER RIDGE TO THE WEST. MTF && .HYDROLOGY... 410 AM CDT THE VERY MOIST AIR MASS WILL SUPPORT EFFICIENT RAINFALL PRODUCTION FROM ANY THUNDERSTORMS TODAY AND TONIGHT. THIS MAY PRESENT FLASH FLOODING ESPECIALLY ON THE LOCAL LEVEL AS OPPOSED TO ANY WIDESPREAD THREAT. THAT AND THE FACT THERE IS NOT A GREAT SET UP FOR TRUE TRAINING STORMS IS WHY NO FLASH FLOOD WATCH AT THIS TIME. HOWEVER...IF ANY STORMS ARE IN A PARTICULARLY VULNERABLE AREA...SUCH AS A METRO OR A QUICK-RESPONDING WATERSHED...IT COULD BE TROUBLE. THESE TYPE OF HIGH RATES WERE ALREADY SEEN YESTERDAY MORNING WITH A NARROW SWATH OF ONE AND A HALF TO ESTIMATED THREE PLUS INCHES OF RAIN SEEN FROM RE-FIRING STORMS IN THE WEST CHICAGO METRO. HIGH RESOLUTION MODEL GUIDANCE INDICATES SUCH SWATHS ARE PROBABLE IN THE REGION THIS AFTERNOON INTO TONIGHT ALTHOUGH WHERE IS STILL UNCERTAIN. THE GENERAL RAINFALL FORECAST IS FOR MOST AREAS TO SEE AROUND AN INCH OR A LITTLE OVER BY WEDNESDAY MORNING. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 16Z... * ONE BAND OF SCATTERED TSRA EXPECTED BETWEEN 17-19Z...VERY BRIEF IFR VSBY POSSIBLE. * NEXT ROUND OF TSRA EXPECTED LATE TOWARD 20/21Z FROM THE WEST...BETTER ORGANIZATION AND LOWER VSBY IS MORE LIKELY WITH THIS ROUND. * SOME CHANCE OF ADDITIONAL SHRA/TSRA LATE TONIGHT OR EARLY WEDNESDAY MORNING. MDB //DISCUSSION...UPDATED 16Z... CONVECTIVE POTENTIAL STARTING TO BECOME A BIT MORE CLEAR. ONE CLUSTER OF SHRA/TSRA CONTINUES TO APPROACH FROM THE WEST WITH FLUCTUATIONS IN INTENSITY AND COVERAGE. INDIVIDUAL TS CELLS ARE PRETTY SMALL BUT CONTINUE TO POP SO WILL CARRY VCTS AND A PERIOD OF TEMPO TS AT THE TERMINALS OVER THE NEXT FEW HOURS...THOUGH COVERAGE MAY BEGIN TO WANE. VERY BRIEF IFR VSBY IS POSSIBLE UNDER THE HEAVIER CELLS. THE NEXT ROUND OF STORMS IS TAKING SHAPE ACROSS EASTERN AND SOUTH CENTRAL IOWA WHICH WOULD ARRIVE IN THE AREA MID TO LATE AFTERNOON. THERE SHOULD BE SHORT BREAK IN TS BEHIND THE INITIAL AREA BEFORE THIS NEXT AREA ARRIVES. THIS SECOND AREA WILL LIKELY BE MORE WIDESPREAD IN COVERAGE WITH LONGER PERIODS OF LOW VISIBILITY POSSIBLE...ALONG WITH THE POTENTIAL FOR GUSTY WINDS. THIS ALSO POINTS TO THE EVENING HOURS BEING QUIET SO WILL NEED TO RE-EVALUATE SHRA/TSRA MENTION THEN. MDB FROM 12Z... RELATIVELY QUIET ACROSS THE TERMINALS THIS MORNING WHILE SOME FOG/HAZE REMAINS OVERHEAD...BUT WITH THE MORE DENSE FOG REMAINING AWAY FROM THE TERMINALS AT THIS TIME. ANY FOG THIS MORNING SHOULD QUICKLY DISSIPATE OVER THE NEXT HOUR WITH ANY THREAT OF LOWER VIS/CEILINGS COMING SOUTH DOWN THE LAKE REMAINING LOW AT THIS TIME. ALTHOUGH THIS AREA IS STILL SLOWLY MOVING SOUTH DOWN THE LAKE...VEERING WINDS AND SHOULD HELP LIMIT THIS SOUTHWARD MOMENTUM KEEPING THIS FOG NORTH OF THE TERMINALS. THEN SHIFT GEARS TO REDEVELOPMENT OF SHOWERS/TS LATER THIS MORNING...AS PRECIP DEVELOPS OUT AHEAD OF AN APPROACHING MID LEVEL DISTURBANCE. AS THIS DISTURBANCE DRAWS NEAR...EXPECT CURRENT THUNDERSTORMS OVER IOWA AS WELL AS OTHER DEVELOPMENT TO MOVE ACROSS THROUGH NORTHERN ILLINOIS/NORTHWEST INDIANA BY MID DAY WITH SOME UPWARD GROWTH IN COVERAGE AND INTENSITY EXPECTED INTO THE EARLY AFTERNOON. DO EXPECT A BRIEF LULL IN THE ACTIVITY AFTER THIS INITIAL PRECIP MOVES THROUGH...BUT WITH DEVELOPMENT STILL POSSIBLE GOING INTO THE EARLY EVENING. STILL MONITORING THE POTENTIAL FOR A MORE WIDESPREAD AREA OF THUNDERSTORMS TO MOVE ACROSS THE TERMINALS LATER THIS EVENING AND OVERNIGHT. ALTHOUGH IT STILL SEEMS FAVORABLE FOR THIS TO MOVE ACROSS THE TERMINALS...WILL NEED TO MONITOR LATER TRENDS AFTER THIS INITIAL PRECIP THIS AFTERNOON MOVES THROUGH. WINDS REMAIN LIGHT/VARIABLE THIS MORNING BUT ANTICIPATE A TREND TOWARDS AN EAST NORTHEAST WIND OVER THE NEXT SEVERAL HOURS. WINDS ALONG THE LAKE ARE ALREADY THIS EASTERLY COMPONENT AND WITH THE SUN RISING COINCIDING WITH A WEAK GRADIENT...FEEL THAT IT WONT TAKE MUCH FOR THIS NORTHEAST WIND TO DEVELOP OVER ORD/MDW/GYY THIS MORNING. THEN EXPECT A SLOW TREND TOWARDS THE SOUTHEAST AND EVENTUALLY SOUTH THIS AFTERNOON/EVENING...BEFORE WINDS CONTINUE TO VEER TO THE WEST OVERNIGHT. RODRIGUEZ //ORD AND MDW CONFIDENCE...UPDATED 16Z... * HIGH CONFIDENCE IN BAND OF SHRA/TSRA 17-19Z...MAY BE FAIRLY SCATTERED THOUGH...HIGH CONFIDENCE THAT ANY IFR VSBY WOULD BE BRIEF. * MEDIUM-HIGH CONFIDENCE IN ADDITIONAL ACTIVITY ARRIVING LATER THIS AFTERNOON AND IT WOULD BE MORE WIDESPREAD AND INTENSE...MEDIUM CONFIDENCE IN TIMING. * LOW CONFIDENCE IN POTENTIAL FOR ADDITIONAL ACTIVITY TONIGHT/WEDNESDAY MORNING. MDB //OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z... WEDNESDAY NIGHT...VFR. THURSDAY...VFR. FRIDAY...VFR. SATURDAY...VFR. SUNDAY...VFR. MONDAY...VFR. RODRIGUEZ && .MARINE... 427 AM CDT MAIN FORECAST CONCERN IN THE NEAR TERM IS FOR AREAS ACROSS THE NORTHERN TWO THIRDS OF THE LAKE...WHERE DENSE FOG HAS SETTLED IN. EXPECT THIS FOG TO PERSIST AT LEAST THROUGH THE AFTERNOON WITH CURRENT THINKING THAT THIS FOG WILL CHURN UP WITH APPROACHING PRECIP. ALTHOUGH CONFIDENCE IS LOW...AND ITS POSSIBLE THE CURRENT DENSE FOG ADVISORY IN PLACE THROUGH THE AFTERNOON COULD NEED TO BE EXTENDED THROUGH THE EVENING. THERE IS ALSO POTENTIAL FOR THE MORE DENSE FOG TO PUSH FURTHER DOWN THE LAKE EARLY THIS MORNING...BEFORE WINDS BEGIN TO SHIFT AND BRING A STOP TO THIS SOUTHWARD MOVING AREA OF FOG. CURRENT LIGHT NORTHERLY WINDS IN PLACE ACROSS THE LAKE WILL TURN MORE SOUTHERLY THROUGHOUT TODAY AS THE NEXT SYSTEM APPROACHES FROM THE WEST. AS THIS SYSTEM THEN PROGRESSES ACROSS THE LAKE TONIGHT...EXPECT SOUTHWEST WINDS TO BECOME MORE WESTERLY WHILE INCREASING MORE TOWARDS THE 10 TO 20 KT RANGE. THEN AS HIGH PRESSURE SLOWLY BUILDS EAST TOWARDS THE LAKE...EXPECT GENERALLY NORTHERLY WINDS THROUGH THE REST OF THE WORK WEEK. RODRIGUEZ && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...DENSE FOG ADVISORY...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565- LMZ567-LMZ669-LMZ671-LMZ673-LMZ868-LMZ870-LMZ872-LMZ874 UNTIL 3 PM TUESDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1244 PM CDT TUE JUL 9 2013 .UPDATE... ISSUED AT 1050 AM CDT TUE JUL 9 2013 2 MAJOR UPDATES HAVE BEEN SEND THIS MORNING...REFLECTING CHANGES BASED ON RADAR TRENDS...AND NOW BOTH CONVECTIVE TRENDS COMBINED WITH MORNING UA ANALYSIS AND EARLY SIGNALS IN MODEL GUIDANCE. THE PARADE OF TWO MCV FEATURES IS NOTED ON RADAR AND SATELLITE...AND THUS THE NEXT 4 HOURS WILL CERTAINLY BE OUR MAIN SHOW WITH RESPECT TO RAINFALL POTENTIAL. AMOUNTS THUS FAR ARE SCATTERED AND SIGNIFICANT ...OVER 1 INCH......BUT MOST OF THE AREA RECEIVING ONLY LIGHT AMOUNTS OR NEARLY DRY...ESPECIALLY SOUTH. SURFACE CAPE WILL BE LIMITED TO ONLY THE SOUTH TODAY AND EARLY THIS EVENING...THUS OUR BEST POTENTIAL FOR MORE SIGNIFICANT STORMS IS THERE. ELSEWHERE I HAVE CONTINUED TO LOWER EVENING POPS...AS WELL AS AFTERNOON POPS IN THE WEST. TONIGHT COULD VERY WELL BE DRY OVER OUR WESTERN 1/3 OF THE CWA...AND POSSIBLY WESTERN 2/3 IF THE VEERED MOISTURE PLUME CANNOT RECOVER FROM THE MCV PASSAGES. THIS GREATLY WILL LOWER THE SEVERE THREAT...AND I WILL AWAIT THE SPC UPDATE BEFORE UPDATING THE HWO TO REFLECT THAT POSSIBLE LOWERED MAGNITUDE OF THE THREAT. TEMPERATURES HAVE BEEN LOWERED TO MAINLY MID 80S HIGHS...WHICH SHOULD EASILY OCCUR ONCE CONVECTION STOPS FIRING...BUT SAFE TO SAY...OUR NEAR ADVISORY LEVEL HEAT WILL NOT VERIFY TODAY. IT WILL MOST CERTAINLY BE QUITE MUGGY OUT THERE. ERVIN && .SYNOPSIS... ISSUED AT 330 AM CDT TUE JUL 9 2013 06Z MSAS SFC ANALYSIS SUPPORTIVE OF WEAK LOW OVER CENTRAL SD WITH STATIONARY FRONT EXTENDING SEWD FROM THE LOW AND BISECTING EASTERN IA AND NORTHWEST IL. MOISTURE IS POOLING ALONG THE FRONT WITH DEWPTS OF 70-75F. 00Z KDVN RAOB SHOWS DEEP MOISTURE WITH PRECIPITABLE WATER VALUES OF NEARLY 2 INCHES... WHICH IS AROUND 160 PERCENT OF NORMAL AND NEARLY 2 STANDARD DEVIATIONS ABOVE THE MEAN. CONVECTIVELY ENHANCED VORT MAX IS TRACKING THROUGH EASTERN NE ATTM WITH RADARS SHOWING SHOWERS AND STORMS AHEAD OF THIS FEATURE INTO WESTERN IA. ADDITIONAL COMPLEX OF STORMS WAS OVER THE DAKOTAS AHEAD OF COLD FRONT AND SHORTWAVE MOVING EAST THROUGH FAR SOUTHERN ALBERTA PROVINCE AND NORTHERN MT. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 330 AM CDT TUE JUL 9 2013 SUGGESTIONS OF 2 MAIN ROUNDS OF STORMS THROUGH THE PERIOD. AS CONVECTIVELY ENHANCED VORT MAX MOVES EAST FROM NE ANTICIPATE SHOWERS AND STORMS TRACKING AHEAD OF THIS FEATURE TO MOVE ACROSS THE REGION BY MID AM THROUGH EARLY AFTN. PRIOR TO THE ARRIVAL OF THESE STORMS COULD SEE ADDITIONAL DEVELOPMENT PRIOR TO MID AM OVER THE AREA WITH WARM ADVECTION WING. POTENTIAL FOR SOME STRENGTHENING OF MID LEVEL WINDS AND INTENSIFICATION OF STORMS BY LATE AM AND AFTN FOR RISK OF FEW STRONG TO ISOLD SEVERE STORMS WITH MOST RECENT RUNS OF HRRR 2-5KM UPDRAFT HELICITY AND 3 KM VELOCITY CONTINUING TO SUGGEST THIS RISK NEAR AND ESPECIALLY NORTH OF I-80. MAY SEE BREAK IN ACTION OR RELATIVE LULL IN ACTIVITY BY MID-LATE AFTN WITH FOCUS SHIFTING BACK NORTHWEST FOR DEVELOPMENT AHEAD OF COLD FRONT. LIKELY TO SEE ANOTHER ROUND OF STORMS MOVE THROUGH THIS EVENING INTO OVERNIGHT AHEAD OF COLD FRONT. STRENGTHENING 40-60 KT MID LEVEL SPEED MAX SPREADING BEHIND FRONT COUPLED WITH VERY UNSTABLE ENVIRONMENT WILL SUPPORT RISK OF SEVERE STORMS WITH POTENTIAL FOR UPSCALE GROWTH TO LINEAR MCS WITH MAINLY DAMAGING WIND THREAT. HEAVY RAIN WILL BE A CONCERN AS WELL GIVEN THE DEEP ALMOST TROPICAL MOISTURE IN PLACE. STORMS SHOULD BE MOVING ALONG MORE THAN WE/VE SEEN OF LATE BUT WILL BE VERY EFFICIENT RAIN PRODUCERS WITH RATES LIKELY 1-2"/HR. THUS... CANT RULE OUT SOME LOCALIZED FLASH FLOODING AND WILL HAVE TO BE ESPECIALLY WATCHFULL OVER PORTIONS OF DELAWARE AND DUBUQUE COUNTIES WHICH HAVE SEEN 2-5 INCHES PAST 24-36 HRS. EXPECT PCPN SHOULD BE DIMINISHING FROM NW TO SE OVRNGT WITH PASSAGE OF COLD FRONT. HIGHS TDY TRICKY WITH CLOUDS AND PCPN BUT OVERALL SHOULD RANGE FROM MID 80S TO THE LOWER 90S. SOME MIXING OUT OF DEWPTS MAY OCCUR BUT AT LEAST UPPER 60S TO LOWER 70S EXPECTED ON DEWPTS... WHICH COMBINED WITH TEMPS WILL MAKE FOR HEAT INDICES MAINLY IN THE MID TO UPPER 90S. COOLER AND DRIER AIR LAGS BEHIND FRONT TNGT... THUS LOWS ONLY DROP INTO THE UPPER 60S TO LOWER 70S. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 330 AM CDT TUE JUL 9 2013 WEDNESDAY AND THURSDAY...AS L/W TROF CONTINUES TO DEEPEN AND ESTABLISH ACRS THE GRT LKS...SEASONABLY STRONG LLVL HIGH PRESSURE WILL LOOK TO DUMP DOWN THE NORTHERN PLAINS AND MO RVR VALLEY ON WED. A FEW POST-FRONTAL SHOWERS AND STORMS MAY BE OCCURRING ACRS THE FAR EASTERN/SOUTHERN CWA WED MORNING BUT BULK OF THE ACTIVITY SHOULD BE GONE BY 15Z. VEERING AND INCREASING BOUNDARY LAYER FLOW AS WELL AS INCOMING SUBSIDENCE SHOULD CLEAR THINGS OUT ON WED...BUT SOME LAG IN CAA TO ALLOW TEMPS TO WARM INTO THE LOW TO MID 80S EVEN POST- FRONTALLY. A RATHER BREEZY NORTHWEST TO NORTH WIND OF 15-20 MPH. CLEAR SKIES AND WIND DROP OFF WED NIGHT TO ALLOW SOME AREA TEMPS TO DROP OFF INTO THE 50S. LLVL HIGH PRESSURE CONTINUING TO MIGRATE EASTWARD ACRS THE REGION TO MAKE FOR A CHAMBER OF COMMERCE DAY THU WITH HIGHS IN THE UPPER 70S TO LOWER 80S...SUNSHINE AND LOWER HUMIDITY. THU NIGHT SEASONABLY COOL AGAIN WITH LOWS IN THE 50S AND LOW 60S. FRIDAY THROUGH NEXT MONDAY...TRENDS OF THE LATEST RUN 00Z MEDIUM RANGE SOLUTIONS AND ENSEMBLES SUGGEST SOME DIGGING TROFFINESS IN THE PACIFIC NORTHWEST/WESTERN CANADA TO TRANSLATE INTO PUMPED UP UPPER RIDGING ACRS THE MID CONUS FRI INTO SAT. THUS WHILE THERMAL DOME INTENSIFIES ACRS THE GRT BSN INTO THE SOUTHWESTERN PLAINS...MCS TRACK/RING OF FIRE PATTERN TO ESTABLISH IN NORMAL DEEP SUMMER LOCATION OF NORTHWESTERN HIGH PLAINS...UPPER MS RVR VALLEY...SOUTHERN CANADA AND INTO THE GRT LKS. LATEST INDICATIONS SUGGEST A LESSENING CHANCE FOR SOME OF THIS MCS ACTIVITY TO SPILL DOWN ACRS THE NORTHERN CWA EITHER FRI NIGHT OR SAT NIGHT WHILE TEMPERATURES START TO REBOUND BACK TO NORMAL OR EVEN WARMER. BY SUNDAY...WESTERLIES FIRMLY ESTABLISH ACRS THE U.S.-CANADIAN BORDER REGION WITH UPPER RIDGING DOMINATING ACRS THE SOUTHERN 2/3S OF THE CONUS. LONGER RANGE THERMAL PROFILES SUGGEST ENOUGH AIRMASS MODIFICATION TO DRIVE SUNDAY HIGHS UP INTO AT LEAST THE LOWER 90S ALONG WITH INCREASING SFC DPTS/HUMIDITY. PASSING WAVE IN THIS PROGRESSIVE FLOW MAY TRY TO SHUNT DOWN A WEAKENING SFC BOUNDARY DOWN TOWARD OR ACRS THE CWA LATER SUNDAY NIGHT OR MONDAY AND GET SLOWED AS IT ALIGNS PARALLEL TO MEAN STEERING FLOW. THUS THIS WINDOW MAY BE THE NEXT REAL CHANCE FOR SOME PRECIP IN THE AREA AFTER TODAY/TONIGHT. LONGER RANGE SIGNALS ON THE LATEST RUNS ESPECIALLY THE NEW 00Z ECMWF SUGGESTS THAT THIS BROAD UPPER RIDGING PATTERN TO CONTINUE TO REIGN ACRS MUCH OF THE CONUS WELL INTO MID NEXT WEEK...WHILE THE TROPICS CONTINUE TO GET INTERESTING. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON) ISSUED AT 1239 PM CDT TUE JUL 9 2013 AS SCATTERED SHOWERS AND STORMS MOVED OVER EASTERN IOWA AND ILLINOIS EARLIER TODAY...THEY REMOVED MUCH OF THE INSTABILITY NEEDED FOR THE EALIER FORECAST STRONG THUNDERSTORMS. THUS...ANY NEW AFTERNOON THUNDERSTORMS AND EVENING STORMS WILL BE MORE SCATTERED THAN WIDESPREAD...AND DUE TO THIS LOW COVERAGE AND LOW CONFIDENCE...ALL STORMS HAVE BEEN REMOVED FROM TAFS. VFR CONDITIONS WITH MID AND HIGH CLOUDS OR CLEAR SKIES...AND SOUTH WINDS WILL CONTINUE THROUGH LATE EVENING...WHEN THE COLD FRONT ARRIVES. AS THE FRONT ARRIVES...WINDS MAY DECREASE ALLOWING FOR PATCHY FOG DEVELOPMENT...AND A TEMPO FOR FOG HAS BEEN PLACED INTO ALL TAFS FROM AROUND 04Z TO 08Z TONIGHT. AFTER THIS...NORTHWEST WINDS SHOULD DISSIPATE FOG...AND RETURN TO VFR CONDITIONS. ERVIN && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ UPDATE...ERVIN SYNOPSIS...05 SHORT TERM...05 LONG TERM...12 AVIATION...ERVIN
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
302 PM CDT TUE JUL 9 2013 ...UPDATED SHORT TERM... .SYNOPSIS... ISSUED AT 300 PM CDT TUE JUL 9 2013 ON THE SYNOPTIC SCALE, A MUCH MORE ZONAL FLOW HAS DEVELOPED ACROSS THE CONUS WITH A POLAR JET FOCUSES ACROSS THE NORTHERN STATES, AND A BROAD MID LEVEL SHORTWAVE EMBEDDED IN THE FLOW ACROSS EASTERN MONTANA. TEMPERATURES WARMED INTO THE UPPER 80S TO AROUND 90 DEGREES BY 11 AM ACROSS SOUTHWEST AND SOUTH CENTRAL KANSAS. TEMPERATURES WERE SLIGHTLY SLOWER TO RESPOND ACROSS SECTIONS OF WEST CENTRAL KANSAS WHERE BANDS OF MID LEVEL STRATOCUMULUS WERE PRESENT. THIS PATTERN INCLUDES A FLATTENING OF THE UPPER ANTICYCLONE NOW LOCATED FROM THE DESERT SOUTHWEST INTO THE SOUTHERN PLAINS. THE 12 UTC 700 MB ANALYSIS SHOWED A WARM PLUME OF MID LEVEL AIR ACROSS EASTERN COLORADO AND WESTERN KANSAS AS WARM AS 15 DEGREES C. THE 850 MB LEVEL TROUGH WHICH EXTENDED ACROSS THE NORTHERN AND CENTRAL HIGH PLAINS CREATED A DOWNSLOPE SURFACE WIND FIELD OVER SOUTHWEST AND CENTRAL KANSAS WITH TEMPERATURES IN THE UPPER 20`S C. AT THE SURFACE, A BETTER IDENTIFIED COLD FRONT BASED ON SURFACE MOISTURE DISCONTINUITY EXTENDED ACROSS WESTERN NEBRASKA THROUGH THE EASTERN DAKOTAS, WHILE AN AREA OF LOW PRESSURE AHEAD OF THE BOUNDARY EXHIBITED ANS ATTENDANT TROUGH FROM CENTRAL NEBRASKA INTO WEST CENTRAL KANSAS. JUST AHEAD OF THE SURFACE TROUGH, DEW POINTS OF 60 TO 65 DEGREES CONTRIBUTED TO PRECIPITABLE WATER VALUES IN EXCESS OF AN INCH AND A HALF THROUGH THE INTERSTATE 70 AND HIGHWAY 156 CORRIDORS. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 300 PM CDT TUE JUL 9 2013 THE HEAT AND CONVECTIVE CHANCES INCLUDING POTENTIAL IMPACTS ARE THE MAIN FORECAST ISSUES EARLY IN THE SHORT TERM. THE HEAT ADVISORY WILL BE MAINTAINED IN IT`S CURRENT CONFIGURATION ALTHOUGH THE WESTERN PERIPHERY MAY BE SUSPECT TO MEETING LOW END ADVISORY CRITERIA DUE TO SURFACE DEW POINTS THAT HAVE MIXED OUT INTO THE MID/UPPER 50`S. IF THE TREND CONTINUES INTO EARLY AFTERNOON, IN EFFECT TEMPERATURES ALSO ARE NOT TRENDING AS WARM AS FORECAST, SOME AREAS ALONG THE WESTERN PERIPHERY MAY NEED TO BE TRIMMED FROM THE ADVISORY. THE NAM/ WRF NMM AND ARW ALL DEVELOP CONVECTION ALONG THE FRONTAL BOUNDARY EXTENDING INTO NORTHWEST KANSAS THIS AFTERNOON. SIGNIFICANT DIFFERENCES IN COVERAGE EXISTS BETWEEN THE MODELS, VARYING FROM RATHER ISOLATED CLUSTERS TO MORE ORGANIZED LINE SEGMENTS WITH PROLIFIC OUTFLOW. THE HRRR IS PARTICULARLY AGGRESSIVE WITH DEVELOPING HEAVY QPF AND RAIN COOLED OUTFLOW OF 30 KNOTS LOCALLY RIGHT AHEAD OF THE FRONT ALONG THE MAXIMUM DEW POINT AND PWAT GRADIENT. HOWEVER THE WEATHER EVOLVES THIS AFTERNOON AND EVENING MAY HAVE AN IMPACT ON TEMPERATURES AND CONVECTIVE CHANCES AGAIN ON WEDNESDAY AFTERNOON. HOWEVER, THE BETTER CHANCE FOR CONVECTION ON WEDNESDAY WILL LIKELY OCCUR DUE TO DIFFERENTIAL HEATING OVER THE HIGHER TERRAIN OF EASTERN COLORADO, INCREASING CHANCES ACROSS WESTERN KANSAS INTO WEDNESDAY EVENING. HIGHS WEDNESDAY WILL BE AROUND 10 DEGREES COOLER BEHIND THE BOUNDARY. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 215 PM CDT TUE JUL 9 2013 A WARM AND FAIRLY DRY PERIOD BEGINS AFTER WEDNESDAY NIGHT AS A LARGE RIDGE OF UPPER LEVEL HIGH PRESSURE BUILDS INTO THE PLAINS. FOR WEDNESDAY NIGHT WILL MAINTAIN A 30 TO 40 PERCENT CHANCE OF THUNDERSTORMS JUST NORTH OF A WEAK FRONTAL BOUNDARY IN MOIST UPSLOPE REGIME ACROSS MUCH OF WESTERN KANSAS. THIS WILL BE OUR BEST CHANCE OF SEEING MEASURABLE RAINFALL INTO NEXT WEEK. WITH WEAK WINDS ALOFT NOT EXPECTING SEVERE WEATHER. THERE COULD BE SOME LOCALLY HEAVY DOWNPOURS IF STORMS GET GOING AND THEY ARE SLOW MOVING. A WESTWARD MOVING UPPER LOW BEGINS TO UNDERCUT THE RIDGE ACROSS THE SOUTHERN AND CENTRAL PLAINS FROM SUNDAY INTO TUESDAY WITH A SLIGHT CHANCE OF THUNDERSTORMS ON MONDAY NEAR A CONVERGENCE LINE, ALONG WITH SLIGHTLY COOLER TEMPERATURES. OVERNIGHT LOWS WILL BE MILD AROUND 70 TO 75 THROUGH THE PERIOD. DAYTIME HIGHS WARM BACK TO AROUND 100 TO 105 ON FRIDAY AND SATURDAY THEN COOL SLIGHTLY BACK INTO THE MID TO UPPER 90S INTO NEXT TUESDAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON) ISSUED AT 200 PM CDT TUE JUL 9 2013 WITH THE EXCEPTION OF THE POSSIBILITY OF SEVERE CONVECTION PRODUCING 40 TO 50 KNOT WIND GUSTS LATE THIS AFTERNOON AND EARLY EVENING, THE AREA INCLUDING THE LOCAL TERMINALS WILL BE UNDER VFR CONDITIONS. CONVECTION MAY DEVELOP ALONG A SURFACE FRONT NORTHWEST OF HAYS BETWEEN 21 AND 00 UTC. THE ATMOSPHERE IS CONDUCIVE TO PRODUCING WIDESPREAD THUNDERSTORMS OUTFLOW, WITH LOCALLY SEVERE GUSTS IN A ONE TO TWO HOUR EPISODE ENDING IN THE EARLY EVENING. && .PRELIMINARY POINT TEMPS/POPS... DDC 72 97 70 98 / 40 30 30 10 GCK 71 95 69 99 / 40 30 30 10 EHA 71 96 69 101 / 20 30 30 10 LBL 72 98 70 102 / 30 30 30 10 HYS 72 94 69 95 / 40 20 20 20 P28 76 100 72 97 / 40 20 20 20 && .DDC WATCHES/WARNINGS/ADVISORIES... HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR KSZ030-031-044>046- 064>066-078>081-088>090. && $$ SYNOPSIS...RUSSELL SHORT TERM...RUSSELL LONG TERM...KRUSE AVIATION...RUSSELL
AREA FORECAST DISCUSSION
NWS JACKSON KY
329 PM EDT TUE JUL 9 2013 .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT) ISSUED AT 329 PM EDT TUE JUL 9 2013 ISOLD TO SCT SHOWERS AND THUNDERSTORMS ARE DEVELOPING ACROSS THE AREA THIS AFTERNOON. MORE SUBSTANTIAL AREA OF CONVECTION HAS FIRED OVER OHIO. HRRR HAS ACTUALLY BEEN DOING DECENT WITH CONVECTIVE INITIATION ACROSS AREAS NORTH OF THE OHIO RIVER. IN GENERAL IT KEEPS THE BULK OF ACTIVITY NORTH AND EAST OF OUR CWA...THOUGH RADAR TRENDS WOULD SUGGEST THAT OUR NORTHERN AND EASTERN COUNTIES MAY GET BRUSHED. INCREASED POPS ACROSS THE NORTHERN/EASTERN PORTIONS OF OUR CWA FOR THE LATE AFTERNOON AND EARLY EVENING TIME FRAME. PER THE HRRR...WITH COMPLEX OF STORMS PASSING GENERALLY TO OUR EAST THIS EVENING AND LOSS OF DIURNAL HEATING GRADUALLY DROPPED POPS OFF THROUGH THE NIGHT. HOWEVER...RAMPED POPS BACK UP TOWARDS DAWN AS SHORT TERM HIGH RESOLUTION MODELS SUGGEST THE POSSIBILITY OF THE REMNANTS OF ANOTHER COMPLEX OF STORMS ENTERING THE AREA FROM THE NORTHWEST. OTHERWISE...MODELS ARE IN FAIRLY GOOD AGREEMENT THROUGH THE SHORT TERM. A DEEPENING UPPER LEVEL TROUGH AND REFLECTED SFC COLD FRONT WILL GRADUALLY PUSH THROUGH THE REGION WEDNESDAY NIGHT INTO EARLY THURSDAY MORNING. PWATS OVER THE NEXT 36 TO 48 HOURS ARE SIGNIFICANT HITTING CLIMATOLOGICAL HIGHS AT TIMES. FORECAST SOUNDINGS ARE NOT IN AS GOOD AGREEMENT WITH RESPECT TO STORM MOTION THOUGH. THE GFS IS MORE PROGRESSIVE WITH MOVEMENT WHEN COMPARED TO THE HIGHER RESOLUTION RAP AND NAM. REGARDLESS...WITH SUCH HIGH PWATS AND CONSIDERING A FAIRLY SATURATED GROUND FEEL THERE WILL BE THE POTENTIAL FOR SOME LOCALLY HEAVY RAINFALL AND MINOR HYDRO ISSUES...ESPECIALLY WITH THE STRONGER STORMS. CONFIDENCE WAS LACKING WITH RESPECT TO A WIDESPREAD THREAT SO OPTED NOT TO ISSUE ANY TYPE OF FFA. BUT MAY RECONSIDER A FLASH FLOOD WATCH WITH FUTURE FORECAST PACKAGES SHOULD MODELS COME INTO A LITTLE BETTER AGREEMENT WITH RESPECT TO DETAILS...AND SHOW A MORE SIGNIFICANT THREAT. FOR NOW WILL CONTINUE TO COVER THIS POTENTIAL IN THE HWO AND PASS CONCERNS ON TO FUTURE SHIFTS. GENERALLY FOLLOWED INHERITED TEMPS...NUDGING SLIGHTLY TOWARDS A BLEND OF MODEL GUIDANCE. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 329 PM EDT TUE JUL 9 2013 THE MODELS HAVE A SIMILAR IDEA...THROUGH THE EXTENDED...OF A MID LEVEL PATTERN DOMINATED BY A LARGE AREA OF RIDGING...INITIALLY OVER THE SOUTHERN ROCKIES EXPANDING NORTHEAST WITH TIME...AND DOWNSTREAM TROUGHING THROUGH THE GREAT LAKES LATER AFFECTING MUCH OF THE EAST AND DEEP SOUTH. THE GREAT LAKES TROUGH STRENGTHENS A BIT ON THURSDAY AS ITS CORE MOVES EAST AND INTO UPSTATE NEW YORK BY 12Z FRIDAY. AT THE SAME TIME...ITS TRAILING AXIS AND MAIN ENERGY BAND WILL SWEEP SOUTHEAST THROUGH THE LOWER OHIO VALLEY AND ACROSS EAST KENTUCKY. THIS WILL ALLOW HEIGHTS TO BUILD IN FROM THE NORTHWEST THROUGH THE WEEKEND WHILE THE SOUTHERN PORTION OF THE TROUGH CUTS OFF OVER THE DEEP SOUTH AND STARTS TO CONSOLIDATE. THOUGH THE MODELS GENERALLY AGREE ON THE RIDGE PLACEMENT...THEY DIFFER ON THE DETAILS REGARDING THE LOWER HEIGHT CENTERS TO THE SOUTH AND EAST. INTO THIS MIX WILL ENTER THE UPPER HEIGHT FIELD OF CHANTAL...OR WHATEVER BECOMES OF HER...THAT COULD MOVE TO THE SOUTHEAST COAST PER THE GEM OR STAY LOCKED OUT TO THE SOUTH AS SEEN IN THE GFS AND ECMWF. EITHER WAY...ITS MOISTURE MAY START TO IMPACT THE AREA AS EARLY AS LATE SUNDAY...LINGERING THROUGH THE REST OF THE EXTENDED. FOR EAST KENTUCKY...THE RIDGE TO THE NORTH WILL BE A KEY COMPONENT IN DETERMINING OUR WEATHER INTO THE START OF NEXT WEEK. WITH THE MODELS IN BETTER AGREEMENT ON THIS FEATURE CONFIDENCE IS HIGHER IN GOING DRY THROUGH AT LEAST MIDDAY SUNDAY. THEREAFTER...THE GFS...AND TO A LESSER EXTENT THE ECMWF...DOES BRING AN UPPER LOW WEST TOWARD THE AREA FOR TUESDAY. WITH THE DECENT AGREEMENT AMONG THE MODELS ON THE RIDGE THROUGH THE WEEKEND...EXPECT THAT A BLEND WILL BE AN EFFECTIVE STARTING POINT THROUGH SUNDAY. AFTER THAT...WILL LEAN MORE TOWARD THE WEAKER...LESS AMPLIFIED...00Z ECMWF. SENSIBLE WEATHER WILL LIKELY FEATURE SOME ONGOING CONVECTION MOVING SOUTHEAST THROUGH THIS PART OF THE STATE ON THURSDAY MORNING AS A COLD FRONT PASSES THROUGH EARLY IN THE DAY. HIGH PRESSURE WILL THEN BUILD IN AND BRING A RARE SUMMER TIME SHOT OF COOLER AND DRIER AIR FROM THE NORTH. THIS SFC HIGH...AND THE DRY WEATHER...WILL BE SUSTAINED BY THE RIDGING BUILDING ALOFT AND SHOULD SERVE TO KEEP ANY TROPICAL DERIVED MOISTURE OFF TO THE SOUTH AND EAST FOR THE BULK OF THE WEEKEND. HOWEVER...THE RIDGE ALOFT WILL WEAKEN AND MOVE BACK WEST BY LATE SUNDAY WHILE THE CORRESPONDING SFC HIGH WILL ALSO BREAK DOWN AND ALLOW HIGH DEWPOINTS INTO THE REGION FROM THE SOUTHEAST. A DIURNAL REGIME SHOULD THEN GUIDE THE CONVECTIVE DEVELOPMENTS ON MONDAY AND TUESDAY WITH BUILDING INSTABILITY AND LITTLE IN THE WAY OF CAPPING LEADING TO SCATTERED SHOWERS AND THUNDERSTORMS EACH AFTERNOON...PARTICULARLY ACROSS OUR SOUTHEAST COUNTIES. THE CR GRID LOAD CAME IN REASONABLE...THOUGH DID ADJUST POPS A BIT ON SUNDAY AND MONDAY NIGHTS TO BETTER EMPHASIZE THE DIURNAL NATURE OF THE CONVECTION. ALSO...TWEAKED OVERNIGHT LOWS ON THURSDAY THROUGH SATURDAY NIGHTS TO ACCOUNT FOR TERRAIN BASED DIFFERENCES IN RADIATIONAL COOLING WHILE WE ARE BENEFITING FROM THE DRIER AIR MASS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON) ISSUED AT 215 PM EDT TUE JUL 9 2013 EXTENSIVE CUMULUS FIELD WILL BE IN PLACE THROUGH THE REMAINDER OF THE AFTERNOON WITH GENERALLY SCT SKY CONDITIONS AND CLOUD BASES FROM 3000 TO 5000 FEET. WENT WITH VFR CONDITIONS THROUGH THE ENTIRE FORECAST PERIOD. HOWEVER...STILL HAVE TO DEAL WITH CONVECTION THIS AFTERNOON AND INTO TONIGHT. DIURNAL HEATING AND INSTABILITY IS HELPING TO KICK OFF SOME SHOWERS ACROSS THE AREA AT TAF ISSUANCE. ASSESSING THE DIRECT IMPACTS OF SHOWERS AND THUNDERSTORMS AT EACH TERMINAL IS AT BEST DIFFICULT...ESPECIALLY SINCE CELLS APPEAR TO HAVE A RELATIVELY SHORT LIFE CYCLE...BUILDING AND THEN DISSIPATING WITHIN AN HOUR. MORE ORGANIZED CONVECTION MAY DROP SOUTHWARD INTO PORTIONS OF THE AREA LATER THIS EVENING. CLOSELY WATCHING THE DEVELOPMENT AND EVOLUTION OF UPSTREAM ACTIVITY. JKL WOULD BE MOST LIKELY TO BE EFFECTED BY ANYTHING. PRECIP POTENTIAL...LATE AFTERNOON AND EARLY EVENING RAINFALL WOULD BOOST POTENTIAL FOR BR/FOG DEVELOPMENT OVERNIGHT. BUT FOR NOW WENT MORE OPTIMISTIC THAN MODEL GUIDANCE WITH ONLY SOME LIGHT MIST. WINDS WILL RELATIVELY LIGHT THROUGH THE PERIOD...AND GENERALLY FROM THE SOUTHWEST. && .JKL WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM...RAY LONG TERM...GREIF AVIATION...JMW/RAY
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
519 PM EDT TUE JUL 9 2013 .SYNOPSIS... A SERIES OF UPPER DISTURBANCES WILL MAINTAIN CHANCES FOR SHOWERS AND THUNDERSTORMS THROUGH WEDNESDAY. A COLD FRONT WILL MOVE THROUGH EARLY THURSDAY...BRINGING COOLER AND MORE COMFORTABLE CONDITIONS FOR THE END OF THE WEEK. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... AS PREDICTED STORMS ARE FIRING UP ACROSS CENTRAL OHIO AND MOVING SOUTHEAST INTO EAST CENTRAL OHIO. ATMOSPHERE HAS TONS OF ENERGY TO WORK WITH AS ANALYZED BY RAP MODEL. MUCAPES EXCEED 3.0 KJKG-1 WHILE MOISTURE CONV AND EQUIV POT TEMP ADV ARE HIGH SUPPORTING UPSTREAM DEVELOPMENT. BUFR SOUNDINGS SHOW A TROPICAL STATE TO OUR ENVIRONMENT WITH WARM CLOUD PROCESSES IN EFFECT. UPDATED FORECAST TO INCREASE POPS OVER E CENTRAL OHIO AND ADD HEAVY RAIN ATTRIBUTE TO WEATHER GRIDS BASED ON OBSERVED RAINFALL AMOUNTS. LATEST HRRR CONTINUES TO POINTS TO AN MCS TRAVERSING SERN OH AND NRN WV DURING THE OVERNIGHT HOURS. THESE ARE LOCATIONS THAT CAN NOT HANDLE A LOT OF QPF. RAIN AMOUNTS LESS THAN AN INCH PER HOUR WOULD BE ENOUGH TO CREATE FLASH FLOODING. OUR CURRENT FLASH FLOOD WATCH LOOKS GOOD WITH NO CHANGES PLANNED. WITH INCREASED CONFIDENCE PER RECENT HIGH RESOLUTION MODELS...RAISED POP NUMBERS OVER THE AFOREMENTIONED AREA DURING THE NIGHT TIME HOURS. TEMPERATURES WERE LEFT CLOSE TO A BLEND OF GFS LAMP/NAM GUIDANCE TONIGHT. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY/... PCPN ONGOING WED MRNG SHOULD DECR IN CVRG BY MID-MRNG. MDT INSTBY XPCD TO BCM ESTABLISHED THRU FCST AREA BY LATE MRNG OWING TO COOLING MID-LVL TEMPS AND ABUNDANT LOW-LVL MSTR CHARACTERIZED BY DEWPTS IN THE LWR 70S. MRNG CLD CVR XPCD TO BCM BKN AND ALLOW PATCHY HEATING OF THIS VERY MOIST AMS...WHICH WILL AID IN BOTH WEAKENING THE CAP AND STEEPENING LOW-LVL LAPSE RATES. TSTM CVRG XPCD TO INCR MARKEDLY BY EARLY AFTN. DESPITE WEAK MID-LVL FLOW...MDT INSTBY MAY BE SUFFICIENT TO SUPPORT TSTM ORGANIZATION. GIVEN XPCD DRY AIR ATOP DP MOIST LYR...LRG HAIL AND DMGG WIND GUSTS BOTH WILL BE PSBL FROM ANY TSTMS. MRNG CLD CVR WILL RESTRICT HEATING INITIALLY. BUT OVNGT MINIMA IN THE 70S WILL OFFER A HEAD START TO MAXIMA IN THE LWR 80S-MID 80S FOR TMW. PWATS WILL RMN QUITE HIGH THRU WED NGT...PSBLY APRCHG 2.0 IN. SUCH VALUES ARE MORE THAN 2 STANDARD DEVIATIONS ABV NRML VALUES AND WILL ENCOURAGE VERY HIGH PCPN RATES IN TSTMS. FLASH FLOOD WATCH CONTS THRU WED NGT DURG THIS PD OF HIGH PWATS. CDFNT WILL PROGRESS THRU FCST AREA WED NGT...LKLY PROVIDING ADDITIONAL FOCUSED PCPN WED EVE. PCPN WILL SHIFT SEWD OVNGT AND SHOULD VACATE THE FCST AREA BY MID-MRNG THU. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... MODELS ARE NOW IN BETTER AGREEMENT BUILDING IN HIGH PRESSURE FOR THE WEEKEND. THIS WOULD MEAN DRY AND COMFORTABLE CONDITIONS FOR MUCH OF THE LONG TERM. && .AVIATION /21Z TUESDAY THROUGH SUNDAY/... SHOWER AND THUNDERSTORM COVERAGE WILL EXPAND THROUGH THE EVENING HOURS. CIGS AND VIS SHOULD STAY IN THE MVFR/VFR RANGE. IF A TERMINAL IS IMPACTED BY A SHOWER OR STORM THEN A BRIEF PERIOD OF IFR VIS / CIGS ARE POSSIBLE. MVFR FG IS POSSIBLE OVERNIGHT THROUGH MID MRNG WED GIVEN HOW MUCH MOISTURE RESIDES IN THE LLVLS. SHOWERS AND THUNDERSTORMS WILL BE NUMEROUS WED WITH IFR CONDITIONS EXPECTED FOR A BRIEF PERIOD. OUTLOOK.../21Z WEDNESDAY THROUGH SUNDAY/... IFR WEATHER IS POSSIBLE AGAIN THURSDAY IN SHOWERS AND THUNDERSTORMS ASSOCIATED WITH A COLD FRONT. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...FLASH FLOOD WATCH FROM 8 PM EDT THIS EVENING THROUGH LATE WEDNESDAY NIGHT FOR MDZ001. OH...FLASH FLOOD WATCH FROM 8 PM EDT THIS EVENING THROUGH LATE WEDNESDAY NIGHT FOR OHZ039>041-049-050-059. FLASH FLOOD WATCH THROUGH LATE WEDNESDAY NIGHT FOR OHZ048-057- 058-068-069. PA...FLASH FLOOD WATCH FROM 8 PM EDT THIS EVENING THROUGH LATE WEDNESDAY NIGHT FOR PAZ020-021-029-031-073>076. WV...FLASH FLOOD WATCH FROM 8 PM EDT THIS EVENING THROUGH LATE WEDNESDAY NIGHT FOR WVZ001>004-023-041. FLASH FLOOD WATCH THROUGH LATE WEDNESDAY NIGHT FOR WVZ012-021- 022. && $$ SYNOPSIS...34 NEAR TERM...98/34 SHORT TERM...KRAMAR AVIATION...98/34
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
408 PM EDT TUE JUL 9 2013 .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 408 PM EDT TUE JUL 9 2013 WV IMAGERY AND RUC ANALYSIS INDICATED A MAINLY ZONAL PATTERN ACROSS THE NRN CONUS WITH SEVERAL UPSTREAM SHORTWAVE TROUGHS. THE MOST PROMINENT SHRTWV WAS LOCATED OVER ERN MT WHILE A WEAKER IMPULSE AND ASSOCIATED MCS WAS MOVING THROUGH ERN SD. AT THE SFC...A WEAK FRONTAL BOUNDARY LINGERED ACROSS SRN WI WHILE A STRONGER COLD FRONT AHEAD OF THE MT SHRTWV EXTENDED FROM NW ONTARIO INTO NRN ND. A WEAK RIDGE EXTENDED FROM QUEBEC ACROSS LAKE SUPERIOR RESULTING IN LIGHT/CALM WINDS OVERNIGHT. AREAS OF FOG...LOCALLY DENSE...HAS DEVELOPED AS ABUNDANT LOW LEVEL MOISTURE LINGERED BELOW AN INVERSION ABOVE 850 MB. EXPECT THAT THE MORNING WILL BE DOMINATED BY LOW CLOUDS BUT WITH DAYTIME HEATING/MIXING THE LOW CLOUDS ACROSS MOST OF THE AREA WILL THIN OUT ENOUGH BY THIS AFTERNOON FOR TEMPERATURES TO CLIMB INTO THE LOWER 80S INLAND. SATELLITE TRENDS...SHORTER TERM MODELS AND CAPE GRADIENT...SUGGEST THAT THE ERN SD MCS WILL TRACK TO THE EAST INTO W AND SRN WI. THERE IS SOME UNCERTAINTY REGARDING THE IMPACTS OF THE MCS ON CONVECTION DEVELOPING FARTHER TO THE NORTH. THE FORCING ASSOCIATED WITH THE APPROACHING NRN PLAINS SHRTWV WITH 100M HEIGHT FALLS AND MODERATE 700-300 QVECTOR CONV WILL ALSO BE STRONGEST TO THE NORTH OF THE CWA. HOWEVER...THE SRN END OF THE SHRTWV SHOULD STILL BE STRONG ENOUGH TO SUPPORT SCT SHRA/TSRA MOVING FROM NW WI INTO WRN UPPER MI THIS AFTERNOON AND THROUGH THE REST OF THE CWA THIS EVENING. EXPECTED MAX TEMPS AND DEWPOINTS INTO THE MID TO UPPER 60S GIVE CAPE VALUES INTO THE 1K-2K J/KG RANGE...GREATEST WEST CENTRAL. 0-6KM BULK SHEAR VALUES IN THE 30-35 KNOT RANGE WILL BE MARGINAL FOR STRONG/SVR ORGANIZED CONVECTION BUT WITH TSRA MOVING THROUGH DURING PEAK HEATING GIVING DCAPE VALUES IN THE 500-1000 J/KG RANGE...SOME ISOLATED STRONG/DAMAGING WIND GUSTS MAY BE POSSIBLE WITH ANY STRONGER STORMS. THE HIGHER PROBABILITIES FOR SVR STORMS REMAINS TO THE SOUTH WHERE THE INSTABILITY IS GREATEST...PER SPC DAY1 OUTLOOK. THE SHRA/TSRA ARE EXPECTED TO PROGRESS THROUGH THE AREA MOVING INTO THE ERN CWA LATE THIS EVENING AND ENDING OVERNIGHT. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 408 PM EDT TUE JUL 9 2013 SFC HIGH PRESSURE WILL MAKE ITS WAY OVER UPPER MICHIGAN FOR THURSDAY AND FRIDAY...KEEPING WEATHER QUIET FOR THE START OF THE LONG TERM. WITH 850MB TEMPS 12-15C EXPECT AFTERNOON HIGHS ON THURSDAY AND FRIDAY TO BE IN THE UPPER 70S AND LOW 80S INLAND. ADDITIONALLY...DRY AIR ASSOCIATED WITH THIS HIGH /PWATS ROUGHLY 60 PERCENT OF NORMAL/ WILL BRING A NICE BREAK TO THE STICKY HUMID CONDITIONS WEVE EXPERIENCED THIS PAST WEEK. THOUGH IT WILL BE DRY AND WARM...WITH THE RIDGE OVERHEAD WINDS WILL REMAIN VERY LIGHT. THE NEXT CHANCE FOR PRECIPITATION COMES SATURDAY MORNING AND THROUGH THE FIRST PORTIONS OF THE WORK WEEK. THE SFC HIGH PRESSURE SYSTEM OVER THE GREAT LAKES SINKS SOUTHEASTWARD TOWARDS THE MID ATLANTIC STATES AND A LOW PRESSURE SYSTEM MOVES ACROSS THE CANADIAN PRAIRIE...DRAGGING A WEAK TROUGH ACROSS THE AREA DURING THE DAY SATURDAY. MODELS HAVE COME INTO DECENT AGREEMENT THROUGH SATURDAY EVENING...WITH ALL BRINGING PRECIPITATION AHEAD OF THE COLD FRONT INTO THE WESTERN CWA BY APPROX 12Z SATURDAY MORNING. PWATS AHEAD OF THE FRONT REACH UP TO 190 PERCENT OF NORMAL AND MUCAPE VALUES ARE GENERALLY 300-700 J/KG IN THE 12Z SAT-00Z SUN TIME FRAME...AGAIN MAINLY OVER THE WEST AND CENTRAL PORTIONS OF UPPER MI. MEANWHILE...THE EASTERN U.P. FOR THE MOST PART REMAINS UNDER THE INFLUENCE OF A RIDGE EXTENDING FROM THE HIGH PRESSURE THAT SETTLED OVER THE MID ATLANTIC STATES. BOTH THE GFS/ECMWF HAVE THE RIDGE STALLING THE EASTWARD PROGRESSION OF THE FRONT UNTIL SUNDAY NIGHT-MONDAY WHEN A STRONGER SHORTWAVE FORCES IT EASTWARD THROUGH THE CWA. DISCREPANCIES AMONGST THE MODELS SHOW UP LATE SATURDAY NIGHT INTO SUNDAY AS 500MB HIGH PRESSURE SPRAWLS OVER THE CENTRAL CONUS. CONVECTION DEVELOPS ALONG THE EDGE OF THIS RIDGE UNDER THE MORE ZONAL FLOW AT 500MB OVER THE NORTHERN PLAINS AND UPPER MICHIGAN. AS OF NOW...THE ECMWF HAS THE BULK OF THE PRECIPITATION OVER UPPER MI ALONG WITH A MORE DEFINED SHORTWAVE....HOWEVER THE GFS HAS IT MOVING FURTHER SOUTH ACROSS MAINLY WI/ALONG THE WI BORDER WITH A LESS DEFINED SHORTWAVE. OVERALL LOW CONFIDENCE IN MUCH OF ANYTHING THIS FAR OUT AS WHERE/WHEN CONVECTION DEVELOPS OVER THE NORTHERN PLAINS AND HOW IT EVOLVES WILL GREATLY INFLUENCE THE FORECAST. KEPT POPS SIMILAR TO PREVIOUS FORECAST. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON) ISSUED AT 408 PM EDT TUE JUL 9 2013 THE MAIN ISSUES DURING THIS TAF PERIOD WILL BE FOCUSED ON TS CHANCES THIS AFTERNOON WITH MVFR TO IFR CONDITIONS DEVELOPING OVERNIGHT. HAVE PLACED VCTS IN THE IWD TAF AT THE BEGINNING OF THE TAF PERIOD WITH THUNDERSTORMS APPROACHING THE AREA FROM THE SOUTH. CURRENT THINKING IS THAT THIS WILL BE THE MAIN AREA OF CONVECTION THIS AFTERNOON...SHIFTING EASTWARD TO SAW BY 21Z. CMX MAY MISS OUT ON MOST OF THE CONVECTION DUE TO LINGERING CLOUD COVER AN GREATER STABILITY. CEILING AND VISIBILITY WILL LOWER THIS EVENING THROUGH MUCH OF TONIGHT AHEAD OF THE APPROACHING COLD FRONT. IT WOULD NOT BE OUT OF THE QUESTION FOR A FEW RUMBLES OF THUNDER NEAR THE IWD AND SAW TAF SITE BEFORE FROPA...BUT DO NOT EXPECT WIDE SPREAD THUNDERSTORM ACTIVITY. ONCE FRONT PASSES CEILINGS AND VISIBILITY WILL IMPROVE TO VFR CONDITIONS NEAR DAY BREAK WEDNESDAY. WINDS MAY BECOME A BIT GUST BEHIND THE COLD FRONT THROUGH THE DAY WEDNESDAY...WITH GUSTS REACHING NEARLY 25 KNOTS. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 408 PM EDT TUE JUL 9 2013 DENSE FOG REMAINS A CONCERN ACROSS LAKE SUPERIOR TODAY. CLEARING SKIES FOR TUESDAY MORNING SHOULD ALLOW ENOUGH HEATING TO MIX OUT THE MOST DENSE FOG DURING THE AFTERNOON...AT LEAST CLOSER TO THE SHORE. PATCHY FOG WILL THEN LINGER INTO WEDNESDAY BEFORE A COLD FRONT BRINGS DRIER AIR FROM WEST TO EAST ACROSS THE LAKE. WINDS SHOULD BE LIGHT AND GENERALLY VARIABLE THROUGH TUESDAY EVENING. THEN...EXPECT WINDS TO VEER TO THE NW AT 15 TO 25 KNOTS...MAINLY ACROSS THE EAST HALF OF THE LAKE...FOR LATE TUESDAY NIGHT THROUGH WEDNESDAY. HIGH PRESSURE WILL THEN BUILD INTO THE AREA THURSDAY THROUGH SATURDAY AND BRING LIGHT WINDS UNDER 15 KNOTS FOR MUCH OF THE TIME PERIOD. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...KEC LONG TERM...MCD AVIATION...KEC MARINE...KEC
AREA FORECAST DISCUSSION
NWS GAYLORD MI
401 PM EDT TUE JUL 9 2013 .SYNOPSIS... ISSUED AT 401 PM EDT TUE JUL 9 2013 CHANCES OF RAIN SHOWERS AND THUNDERSTORMS WILL OCCUR TONIGHT INTO WEDNESDAY MORNING AS A COLD FRONT APPROACHES THE REGION. BEHIND THE FRONT...HIGH PRESSURE WILL BEGIN TO BUILD IN BY LATE WEDNESDAY...BRINGING COOLER AND LESS HUMID CONDITIONS FOR MIDWEEK. A WARMING TREND WILL THEN FOLLOW FOR LATE IN THE WEEK INTO THE UPCOMING WEEKEND. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 401 PM EDT TUE JUL 9 2013 AN ADMITTEDLY FRUSTRATING FORECAST THIS EVENING...WITH CONFIDENCE DWINDLING ABOUT THE POTENTIAL FOR CONVECTION ACROSS THE CWA... DESPITE WHAT SHOULD (THEORETICALLY AT LEAST) BE A DECENT SETUP. EARLY AFTERNOON ANALYSIS REVEALS A PAIR OF SHORTWAVES TRAVERSING A SEASONABLY STRONG JET STREAM FLOW ACROSS THE NORTHERN TIER...WITH THE FIRST OF THESE WAVES JUST NOW ENTERING WESTERN WISCONSIN. THIS FEATURE HAS BEEN RESPONSIBLE FOR A RATHER LONG-LIVED AXIS OF CONVECTION ALL ACROSS THE UPPER MIDWEST OVER THE PAST 12 HOURS...WITH THIS ACTIVITY JUST NOW WORKING ACROSS SOUTHERN LAKE MICHIGAN. THE AIRMASS ACROSS NORTHERN LOWER REMAINS STUBBORNLY CAPPED THANKS TO A WARM NOSE UP AROUND 750MB PER BOTH RUC AND OBSERVED SOUNDINGS...WITH EARLIER THICK CLOUD COVER EFFECTIVELY LIMITING HEATING AND THUS INSTABILITY. ALL THE WHILE...THE BEST BOUNDARY LAYER MOISTURE REMAINS LAID OUT OVER THE SOUTHERN LAKES ALONG A SUBTLE WARM FRONT...WITH MUCAPE VALUES OF 1500-3000 J/KG NOTED IN THE VICINITY OF THIS FEATURE. NOT SURPRISINGLY...CONVECTION IS DOING THE FAMOUS NORTHERN MICHIGAN SPLIT AS OUR AIRMASS IS JUST PLAIN GARBAGE...FOR LACK OF A BETTER TERM...FEATURING ONLY MUCAPE VALUES PERHAPS PUSHING 700J/KG AT BEST AND THE AFOREMENTIONED CAP. MEANWHILE...A SECONDARY/STRONGER UPPER WAVE IS NOTED DIVING INTO THE NORTHERN PLAINS...HERALDING THE ARRIVAL OF A MUCH COOLER AIRMASS... WITH AN ASSOCIATED COLD FRONT DRAPED OVER NORTHWEST MINNESOTA AS OF 19Z. INTO LATE AFTERNOON AND THE EVENING...APPROACH OF LEAD UPPER WAVE WILL MANDATE AT LEAST A CONTINUED CHANCE FOR SHOWERS AND A FEW STORMS...THOUGH HONESTLY JUST NOT FEELING ANY BIG RAIN CHANCES...AS THE REAL BEEFY CONVECTION SHOULD GET GOING OVER THE SOUTHERN LAKES. AS SUCH...AND GIVEN RADAR TRENDS AND STRONG LACK OF ANY UPSTREAM ADDITIONAL ACTIVITY (JUST SOME FLAT CU ACROSS WISCONSIN)...HAVE TO BELIEVE SCATTERED ACTIVITY WILL JUST ABOUT DO IT...AS PERHAPS WE MAY GET LUCKY ENOUGH TO BUBBLE UP A FEW ADDITIONAL SHOWERS WITH THE INCOMING VORT. NO SEVERE WX THREAT WITH EFFECTIVE SHEAR ONLY ABOUT 20 KNOTS. A BIGGER QUESTION COMES TONIGHT AS THE SECONDARY TROUGH AND COLD FRONT ARRIVE. IT WOULD BE NICE TO SEE AT LEAST A LITTLE UPSTREAM ACTIVITY WITH THIS FEATURE...BUT ALAS THERE IS NOTHING AT THE MOMENT...WITH NOTABLE CAPPING IN PLACE BEHIND THE LEAD WAVE. STILL NOT OUT OF THE QUESTION SOME SHOWERS OR A STORM COULD DEVELOP WITH THE UPPER TROUGH THROUGH THE EVENING...PERHAPS PUSHING INTO OUR AREA OVERNIGHT. HAVING SAID THAT...CONFIDENCE IS LOW ENOUGH TO JUST BARELY MAINTAIN SOME CHANCE POPS AT THIS POINT...WITH MAYBE A FEW LINGERING SHOWERS INTO WEDNESDAY MORNING ACROSS EASTERN COUNTIES. FAIRLY LIGHT FLOW IN ADVANCE OF AND SHALLOW NATURE OF INITIAL COLD FRONT MAY AGAIN ALLOW FOR LOW CLOUDS AND SOME FOG TO DEVELOP OVERNIGHT...PARTICULARLY AS THE FLOW VEERS MORE WESTERLY AND TRIES TO PUSH LAKE MICHIGAN GRUNGE BACK ON LAND. WEDNESDAY NOT LOOKING TOO BAD...WITH ANY PRECIP THREAT DONE BY 15Z...BUT PROBABLY SOME PESKY CU/STRATOCU AS MUCH COLDER AIR BLEEDS IN ALOFT. TEMPS NOTABLY COOLER...WITH HUMIDITY LEVELS DIVING AS DEW POINTS MIX INTO THE 50S. COOLER WITH HIGHS MAINLY IN THE 70S...BUT COULD SNEAK IN A FEW LOW 80S SOUTHEAST COUNTIES ON A GUSTY NORTHWEST FLOW...WITH WIND GUSTS UP TO 25 KNOTS EXPECTED. && .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 401 PM EDT TUE JUL 9 2013 RECENT TRENDS...TEMPERATURES: 1-3C ABOVE NORMAL OVER THE LAST WEEK WITH MOST RECENT WARM SPELL...STATE HAS BEEN MOSTLY SPLIT BETWEEN ABOVE NORMAL TEMPERATURES NORTH AND COOLER TEMPERATURES OVER SOUTHERN LOWER WHICH IS THE NORTHERN EXTENT OF A LARGER AREA OF BELOW NORMAL TEMPERATURES TO START JULY ACROSS THE MID/LOWER MISSISSIPPI VALLEY/OHIO VALLEY AND INTO THE SOUTHEAST THANKS TO RECENT HEAVY RAINFALL. PRECIPITATION/HYDROLOGY: BAND OF MUCH NEEDED RAINFALL YESTERDAY BETWEEN THE M-32 AND M-55 CORRIDORS WITH WIDESPREAD 0.50+ INCH AMOUNTS AND AREAS OF 1-2 INCH AMOUNTS. EASTERN UPPER/TIP OF THE MITT STILL DRY THOUGH...LAST MEASURABLE PRECIP IN THE SAULT WAS JUNE 28. 30 DAY STANDARDIZED PRECIP INDEX CONTINUES ON A DRIER TRENDS ESPECIALLY ACROSS EASTERN UPPER. NORTHERN MICHIGAN SOIL MOISTURE CONTINUES TO DRY OUT (STILL NEAR NORMAL...ABOVE NORMAL NOW CONFINED TO CENTRAL/SOUTHERN LOWER MICHIGAN). SEVEN DAY MEAN DISCHARGE ON AREA RIVERS MOSTLY NEAR NORMAL. LATEST GREAT LAKES LEVELS FORECAST FROM THE ARMY CORPS SHOWS LAKES MICHIGAN/HURON CURRENTLY ABOUT 2 FEET BELOW NORMAL... WITH LITTLE IMPROVEMENT FORECAST THROUGH THE FALL. LARGE SCALE PATTERN/FORECAST...FLAT/EXPANSIVE RIDGE SPANS THE SOUTHERN CONUS AND EXTENDS EAST ACROSS THE SUBTROPICAL ATLANTIC TO THE IBERIAN PENINSULA. MAINLY ZONAL BAND OF WESTERLIES TO THE NORTH OF THIS RIDGE CROSSING THE NORTHERN TIER OF STATES AND ACROSS THE GREAT LAKES...ALL PART OF A LOW AMPLITUDE 4/5 WAVE HEMISPHERIC PATTERN. SHORT WAVE TROUGH MOVING THROUGH THIS BAND OF WESTERLIES ACROSS THE HIGH PLAINS TODAY IS FORECAST TO STRENGTHEN AS IT MOVES INTO THE GREAT LAKES WEDNESDAY AND HOOKS UP WITH HIGH LATITUDE TROUGHING OVER THE ARCTIC TO COOL THINGS OFF FOR A COUPLE OF DAYS. THIS TROUGH WILL SERVE TO SPLIT THE SOUTHERN CONUS RIDGE...ALLOWING HIGHER HEIGHTS TO CONSOLIDATE OVER THE CENTRAL/SOUTHERN PLAINS BY FRIDAY (AND OPEN UP A CHANNEL TO DRAW TROPICAL CYCLONE "CHANTAL" TO THE NORTHWEST TOWARD THE SOUTHEASTERN U.S.). RISING HEIGHTS APPEAR TO BE IN THE OFFING FOR THE UPPER LAKES HEADING INTO THE WEEKEND AS UPPER RIDGE AXIS POKES ITS WAY NORTHEAST...THEN PERHAPS SOME SORT OF BOUNDARY THAT SETTLES IN EARLY NEXT WEEK WITH A FAIRLY STRONG HEIGHT GRADIENT ACROSS CANADA. FORECAST AREA SHOULD BE FIRMLY WITHIN POST-FRONTAL AIR MASS BY WEDNESDAY EVENING AS NORTHWEST BOUNDARY LAYER FLOW PULLS COOLER/ DRIER AIR ACROSS THE UPPER LAKES. TRAILING SHORT WAVE TROUGH WILL FOLLOW LATER WEDNESDAY NIGHT BUT HEIGHT RISES ALOFT AND RISING SURFACE PRESSURES TO ARRIVE THURSDAY...WITH HIGH PRESSURE HOLDING ON INTO FRIDAY. SO FORECAST CONCERNS IN THE NEAR TERM WEDNESDAY NIGHT THROUGH FRIDAY...WEATHER: NOT MUCH AT THIS POINT. SHORT WAVE TROUGH SWINGS THROUGH WEDNESDAY NIGHT...BUT MAY NOT HAVE MUCH MORE THAN SOME MID CLOUD WITH IT. LOW LEVEL THERMAL TROUGH WILL MOVE THROUGH LOWER MICHIGAN DURING THE FIRST HALF OF THURSDAY...MAY ALLOW FOR SOME DIURNALLY FORCED CLOUDS TO POP ACROSS INTERIOR NORTH CENTRAL/NORTHEAST LOWER. BEYOND THAT WEATHER CONCERNS MINIMAL THURSDAY NIGHT (CHILLY) AND FRIDAY. TEMPERATURES...WEDNESDAY NIGHT LOWS MAINLY IN THE 50S...HIGHS THURSDAY PROBABLY A COUPLE DEGREES BELOW SEASONABLE NORMS (MOSTLY 70S). GOOD RADIATIONAL COOLING NIGHT IN STORE THURSDAY NIGHT... FRIDAY MORNING LOWS DOWN IN THE 40S AS A RESULT. HIGHS FRIDAY EXPECTED TO BE CLOSER TO NORMAL (UPPER 70S/LOWER 80S). WINDS...NORTHWEST 10-15 TO START WEDNESDAY EVENING THEN DIMINISHING. NORTH/NORTHWEST 5-15MPH DURING THE DAY THURSDAY THEN BECOMING MOSTLY CALM THURSDAY NIGHT. FRIDAY WINDS SOUTH 5-10MPH EASTERN UPPER... MOSTLY LIGHT/VARIABLE SOUTH OF THE BRIDGE WITH PREDOMINANT LAKE BREEZE CIRCULATIONS RESULTING IN ONSHORE FLOW ALONG THE LAKESHORES. EXTENDED FORECAST (SATURDAY THROUGH TUESDAY)...WILL CONTINUE TO WARM UP SATURDAY AND EXPECTING ANOTHER DRY DAY WITH HIGHS WELL INTO THE 80S. RAIN CHANCES MAY START TO INCREASE SATURDAY NIGHT INTO SUNDAY ESPECIALLY FARTHER NORTH WHERE MAY SEE INCREASED FOCUS ALONG A LOW LEVEL JET. AFTER THAT...HEIGHT FALLS SPREAD INTO CENTRAL/EASTERN CANADA WITH AN ASSOCIATED FRONTAL BOUNDARY FORECAST TO GET STRETCHED OUT IN THE VICINITY OF THE UPPER LAKES. WHETHER SAID BOUNDARY DROPS IN CLOSE ENOUGH TO FOCUS SHOWER/THUNDERSTORM CHANCES EARLY NEXT WEEK IS UNCERTAIN...MAY TRY TO GO DRY MONDAY AND START TUESDAY OUT WITH SOME RAIN CHANCES. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON) ISSUED AT 106 PM EDT TUE JUL 9 2013 A VARIETY OF CONDITIONS WILL CONTINUE ACROSS THE TAF SITES THROUGH LATE AFTERNOON...WITH THE WORST OF THEM AROUND KAPN WHERE IFR STRATUS WILL GRADUALLY LIFT TO MVFR. WILL BE WATCHING A LINE OF SHOWERS AND STORMS TRYING TO CROSS THE LAKE INTO LATE AFTERNOON...AND SUSPECT THIS FEATURE HAS A GOOD CHANCE OF SURVIVAL...SO HAVE PUSHED UP ARRIVAL TIME BY MANY HOURS...THOUGH WITH PREDOMINANTLY VFR CONDITIONS EXPECTED (OUTSIDE OF SOME LOCAL IFR FOR A FEW MINUTES IN HEAVY RAIN). NOT SURE IF WE WILL BE ABLE TO KICK OFF ANYTHING ELSE OVERNIGHT AS A COLD FRONT APPROACHES...BUT STARTING TO HAVE MY DOUBTS...SO WILL REMOVE ALL PRECIP BY 03-06Z AT THE LATEST. INSTEAD...REMAINING MOIST AIRMASS SHOULD GO INTO MORE FOG/STRATUS PRODUCTION...WITH THE EXPECTATION OF MANY SITES ENDING UP IFR ONCE AGAIN. WINDS WILL BE LIGHT THROUGH MUCH OF THE NIGHT...BUT SHIFT TO THE WEST AND BECOME GUSTY UP TO 25 KNOTS ON WEDNESDAY. && .MARINE... ISSUED AT 401 PM EDT TUE JUL 9 2013 FAIRLY LIGHT AND VARIABLE FLOW WILL CONTINUE ON THE GREAT LAKES FOR MUCH OF TONIGHT...AS AREAS OF FOG AND LOW CLOUDS ALSO PERSIST. WINDS WILL SHIFT ABRUPTLY OUT OF THE WEST TO NORTHWEST ON WEDNESDAY...WITH SMALL CRAFT ADVISORY CONDITIONS EXPECTED ACROSS PARTS OF THE NEARSHORE WATERS...MAINLY THROUGH THE STRAITS AND ACROSS NORTHERN LAKE HURON AND WHITEFISH BAY. THOSE GUSTY CONDITIONS WILL SLOWLY ABATE INTO WEDNESDAY NIGHT...WITH AN EXTENDED PERIOD OF LIGHT WINDS AND FAIRLY LOW WAVES FORESEEN TO WRAP UP THE WORK WEEK AS HIGH PRESSURE DRIFTS OVER THE WATERS. && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LH...NONE. LM...NONE. LS...NONE. && $$ SYNOPSIS...NTS SHORT TERM...LAWRENCE LONG TERM...JPB AVIATION...LAWRENCE MARINE...LAWRENCE
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
126 PM EDT TUE JUL 9 2013 LATEST UPDATE... AVIATION .SYNOPSIS... ISSUED AT 335 AM EDT TUE JUL 9 2013 MOST OF THE DAY TODAY SHOULD SEE A GOOD DEAL OF SUNSHINE AND VERY WARM AND HUMID TEMPERATURES AFTER MORNING LOW CLOUDS AND FOG DISSIPATE. THERE WILL BE A SLIGHT CHANCE OF A STORM DURING THE AFTERNOON HOURS. THE BETTER CHANCE OF MORE WIDESPREAD SHOWERS AND STORMS WILL COME TOWARD AND AFTER MIDNIGHT TONIGHT AS A WAVE OF LOW PRESSURE MOVES THROUGH THE AREA. THE CHANCE OF RAIN WILL DIMINISH THROUGH THE DAY ON WEDNESDAY AS A COLD FRONT PUSHES SOUTH THROUGH THE AREA. TEMPERATURES WILL BE A BIT COOLER WEDNESDAY AFTERNOON. EVEN COOLER TEMPERATURES AND DRY CONDITIONS WILL BE FOUND FOR THE REMAINDER OF THE WEEK BEFORE WE START TO WARM UP AGAIN THIS COMING WEEKEND. && .UPDATE... ISSUED AT 1236 PM EDT TUE JUL 9 2013 I HAVE UPDATED OUR GRIDS TO SPEED UP THE TIMING ON THE CONVECTION ASSOCIATED WITH THE MAIN UPPER WAVE COMING THROUGH THE CWA TO THE 6 PM TO 10 PM TIME FRAME. THIS IS BASED ON TIMING THE WATER VAPOR IMAGE LOOPS...THE TIMING ON THE 12Z NAM...GFS...RAP AND THE HRRR AS FAR OUT AS IT GOES. BASED ON THE WATER VAPOR IMAGE LOOPS THE BACK EDGE GETS TO THE LAKE SHORE BY 8 PM AND THE JACKSON...LANSING...ALAMA AREA BY 10 PM. THIS SUGGESTS THE STORM THREAT WILL BE LARGELY OVER BY 10 PM SO I HAVE LIKELY POPS DURING 6 PM TO 10 PM TIME FRAME BUT HAVE ONLY CHANCE POPS AFTER THAT THROUGH 8 AM WEDNESDAY. IF CURRENT TRENDS CONTINUE I WOULD LOWER THE POPS AFTER MIDNIGHT TO BELOW 20 PERCENT. THE LIFT IN THE DGZ ON THE RAP MODEL CONTINUES TO BE THE BEST FEATURE THAT CORRELATES TO THE LOCATION OF THE LIGHTING TODAY. THAT BRINGS THE MAIN LINE OF STORMS THROUGH THE CWA FROM 8 PM (WEST CWA) TILL 10 PM (EAST CWA). HOWEVER THERE IS THE SUGGESTION THERE COULD BE A FEW STORMS DEVELOPING ON THE WARM FRONT...WEST OF JXN ALONG INTERSTATE 94 BY 4 PM. THOSE STORMS SHOULD HEAD NORTHEAST TOWARD LANSING BY 5 TO 6 PM. MODEL SOUNDING MLCAPES ARE FORECAST TO BE IN THE 1500 TO 3000 J/KG RANGE BUT THE DEEP LAYER SHEAR AHEAD OF THE FRONT IS UNDER 25 KNOTS SO I DO NOT EXPECT AN ORGANIZED SEVERE STORM OUTBREAK WITH THIS....JUST SOME ISOLATED WIND DAMAGE REPORTS. WITH THE FREEZING LEVEL NEAR 15,500 FT AND THE -20 NEAR 26,000 FT... HAIL WOULD BE LESS OF A THREAT BUT THERE IS A FAIR AMOUNT OF CAPE IN THE -10 TO -20C LAYER SO I CAN NOT TOTALLY RULE IT OUT. WITH THE FASTER MOVEMENT OF THE SYSTEM TEMPERATURES MAY NOT GET TO 90 DEGREES AFTER ALL SINCE THE CLOUDS WILL BE MOVING IN SHORTLY (BASED ON VISIBLE AND IR LOOPS). STILL WE SHOULD SEE MID TO UPPER 80S INLAND WITH NO PROBLEM. && .SHORT TERM...(TODAY THROUGH THURSDAY) ISSUED AT 335 AM EDT TUE JUL 9 2013 THE MAIN ISSUE IN THE SHORT TERM IS FOG THIS MORNING...THEN STORM POTENTIAL AND SEVERE THREAT FOR LATE TODAY AND TONIGHT. A FAIR AMOUNT OF FOG AND LOW CLOUDS HAVE DEVELOPED OVER THE NRN SECTION OF THE CWFA EARLY THIS MORNING. SOME OF THIS IS STARTING TO DEVELOP FURTHER SOUTH AS A WEAK SFC TROUGH CRAWLING SOUTH ACROSS THE AREA IS LIKELY BEING OVERRUN A BIT JUST OFF THE SFC AND WITH THE HUMID AIR MASS IN PLACE. WE DO EXPECT THAT THIS WILL DISSIPATE DURING THE MID MORNING HOURS AS THE STRONG SUN ANGLE WORKS ON THE SHALLOW LAYER OF MOISTURE. WE EXPECT TO SEE A GOOD DEAL OF SUNSHINE AFTER THE LOW CLOUDS AND FOG DISSIPATE. THE AREA WILL BE UNDER THE INFLUENCE OF SHORT WAVE RIDGING ALOFT BETWEEN THE DEPARTING WAVE FROM YESTERDAY AND THE NEXT WAVE EXPECTED TONIGHT. FCST SOUNDINGS SHOW A WARM LAYER BETWEEN 850-700MB THAT SHOULD CAP MOST IF NOT ALL CONVECTIVE DEVELOPMENT THROUGH ALMOST 00Z. WE CAN NOT RULE OUT AN ISOLATED SHOWER/STORM DEVELOPING ALONG A BOUNDARY LIKE A LAKE BREEZE. THAT SAID...THE LOW LEVEL FLOW LOOKS FAIRLY DIVERGENT DURING THE DAY TODAY WHICH SHOULD LIMIT ANY DEVELOPMENT ALSO. THE AREA STILL LOOKS LIKE IT IS ON TRACK FOR A BATCH OF SHOWERS AND STORMS TO MOVE THROUGH TONIGHT. THE BEST CHANCE WILL OCCUR ALONG AND SOUTH OF INTERSTATE 96. OUR FOCUS IS ON THE SHORT WAVE PRODUCING CONVECTION ACROSS THE DAKOTAS...AND THE EVENTUAL LLJ THAT IS EXPECTED TO DEVELOP THIS EVENING/OVERNIGHT. WE DO EXPECT THE SHORT WAVE TO MOVE INTO THE AREA TOWARD 06Z. IT SEEMS THAT THE CONVECTION ACROSS THE DAKOTAS SHOULD SLOWLY MOVE THROUGH THE DAY. WE COULD SEE IT INTENSIFY A BIT IN WISCONSIN THIS AFTERNOON AS IT ENCOUNTERS BUILDING INSTABILITY THERE. THIS LINE WILL LIKELY DIMINISH SOME AS IT HEADS TOWARD OUR CWFA TONIGHT WITH THE LOSS OF DIURNAL INSTABILITY. WHAT WE WILL SEE IS THE LLJ INCREASE A BIT AND THE NOSE BE AIMED AT THE SRN HALF OF THE CWFA BY 06Z. THIS SHOULD HELP MAINTAIN A FAIRLY DECENT AREA OF SHOWERS AND STORMS THAT WOULD LAST INTO THE DAYBREAK HOURS ON WED BEFORE MOVING OUT. SEVERE THREAT DOES NOT SEEM VERY IMPRESSIVE DUE TO THE LATE NIGHT TIME FRAME THE CONVECTION WOULD BE MOVING IN. FCST SOUNDINGS INDICATE THAT THE CAPE IN THE -10 TO -30C LAYER IS NOT REAL ABUNDANT. DEEP LAYER CLOUD LAYER SHEAR IS ON THE LOWER SIDE AROUND 20-25 KNOTS OR SO. MOST OF THE STORMS WOULD BE ELEVATED WITH SOME POSSIBILITY OF SOME WINDS MAKING IT DOWN WITH SOME RESIDUAL LOW LEVEL INSTABILITY. WE FEEL THAT IF THE STORMS MOVE THROUGH AS EXPECTED TONIGHT...MOST OF THE CWFA WILL BE WORKED OVER ENOUGH FOR WED THAT THE THREAT OF STORMS AND SEVERE WEATHER IS LOW. IT WILL TAKE A WHILE TO BUILD UP THE INSTABILITY...AND THE FRONT SHOULD CLEAR THE CWFA BY PEAK HEATING. THE BEST CHC FOR STORMS WILL BE DOWN SOUTH WHERE LOCATIONS DO NOT SEE MCS ACTIVITY TONIGHT. WE WILL SEE SKIES CLEAR THEN WED EVENING AND CONTINUE THROUGH THU AS DRIER AND COOLER AIR MOVES IN. A SHORT WAVE DOES MOVE THROUGH FROM THE NW ON THU...HOWEVER THE AIR SHOULD BE DRY ENOUGH AND WE WILL BE ON THE DOWNSTREAM SIDE OF THE LONG WAVE RIDGE TO OUR WEST TO KEEP US DRY. .LONG TERM...(THURSDAY NIGHT THROUGH MONDAY) ISSUED AT 335 AM EDT TUE JUL 9 2013 THE ARRIVAL OF MID LEVEL RIDGING EARLY IN THE PERIOD SUPPORTS A DRY PATTERN FOR THE REGION THEN. SUBSIDENCE IS SEEN ON BUFKIT OVERVIEWS AND MOISTURE PROFILES REMAIN DRY THROUGH SAT. A WARM AIR ADVECTION PATTERN SETS UP BY SUNDAY AND PWAT VALUES WILL BE ON THE INCREASE. A WEAKENING SURFACE FRONT SLIPS DOWN FROM THE NORTHWEST SUNDAY NIGHT INTO MONDAY. WITH SOME ELEVATED/SURFACE INSTABILITY ALONG OR AHEAD OF THE FRONTAL ZONE...THERE COULD BE A FEW STORMS. THE BELOW NORMAL TEMPERATURES TO START THE PERIOD TRANSITION TO ABOVE NORMAL VALUES FOR THE END OF THE PERIOD. TEMPERATURE VALUES AT 925 MB CLIMB INTO THE LOW TO MID 20 DEG C RANGE SUNDAY. WITH SOME SUN...WE SHOULD EASILY REACH THE MID 80S. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON) ISSUED AT 126 PM EDT TUE JUL 9 2013 MAIN CONCERN IS TIMING THUNDERSTORMS THIS AFTERNOON. BELIEVE STORMS WILL DEVELOP OVER THE NEXT H0UR ALONG AND SOUTH OF INTERSTATE 94 AND SPREAD EAST-NORTHEAST...AFFECTING MAINLY THE AZO...BTL...JXN TERMINALS. A SECOND WAVE OF EASTWARD MOVING STORMS IS EXPECTED IN THE 00-03Z TIMEFRAME. IT APPEARS THAT LOW CLOUDS WILL AGAIN BE A CONCERN AFTER MIDNIGHT BEHIND THESE STORMS. ALTHOUGH NOT MENTIONED IN THE TAFS...CLEARING OF LOW CLOUDS COULD BE FAIRLY RAPID LATE WEDNESDAY MORNING. && .MARINE... ISSUED AT 335 AM EDT TUE JUL 9 2013 NO HEADLINES WILL BE ISSUED WITH THIS FCST PACKAGE...HOWEVER WE ARE LOOKING AT FOG POTENTIAL THROUGH TONIGHT...ROUGH WEATHER TONIGHT WITH A POSSIBLE ROUND OF STORMS...AND THEN SOME DECENT WINDS POSSIBLE WED BEHIND THE FRONT. THE LIGHT GRADIENT OVER THE LAKE THIS MORNING ALONG WITH THE HUMID AIR MASS OVER THE SOMEWHAT COOL WATER IS LIKELY PRODUCING SOME FOG. WEBCAMS SHOW SOME PLACES SEEING FOG WHILE OTHERS ARE NOT. WE DO NOT FEEL CONFIDENT ENOUGH AT THIS TIME TO ISSUE A MARINE FOG ADVISORY... HOWEVER IT IS SOMETHING WE WILL NEED TO MONITOR. WINDS AHEAD OF THE WAVE MOVING IN TONIGHT WILL HAVE THE POTENTIAL TO INCREASE THE WINDS AND WAVES SOME TONIGHT. THE BIGGER THREAT WILL LIKELY BE THE STORMS THAT ARE ANTICIPATED. THE BEST WIND WILL COME WITH ANY STORMS. A DECENT NW WIND COULD DEVELOP LATE WED AFTERNOON BEHIND THE FRONT THAT PUSHES THROUGH. A SMALL CRAFT ADVISORY MAY BE NEEDED FOR THAT PERIOD. && .HYDROLOGY... ISSUED AT 335 AM EDT TUE JUL 9 2013 THE MAIN PERIOD OF CONCERN AS FAR AS HYDRO IS CONCERNED IS THE TONIGHT PERIOD. WE WILL SEE PRECIPITABLE WATER INCREASE TO AROUND 2.00 INCHES THIS EVENING AHEAD OF THE WAVE THAT WILL MOVE THROUGH THE AREA. THIS WILL PROVIDE THE POTENTIAL OF HEAVY DOWNPOURS ACROSS THE AREA. WE DO NOT ANTICIPATE SIGNIFICANT WIDESPREAD ISSUES AS THIS WAVE THAT MOVES THROUGH SHOULD BE RATHER PROGRESSIVE. AMOUNTS WILL LIKELY BE A QUARTER TO THREE QUARTERS OF AN INCH OF RAINFALL FOR BASIN AVERAGES...WITH SOME LOCAL AREAS SEEING 1-2 INCHES OF RAIN. URBAN AND SMALL STREAM ISSUES WILL BE THE MAIN THREAT. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. && $$ UPDATE...WDM SYNOPSIS...NJJ SHORT TERM...NJJ LONG TERM...MJS AVIATION...TJT HYDROLOGY...NJJ MARINE...NJJ
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
117 PM EDT TUE JUL 9 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 525 AM EDT TUE JUL 9 2013 WV IMAGERY AND RUC ANALYSIS INDICATED A MAINLY ZONAL PATTERN ACROSS THE NRN CONUS WITH SEVERAL UPSTREAM SHORTWAVE TROUGHS. THE MOST PROMINENT SHRTWV WAS LOCATED OVER ERN MT WHILE A WEAKER IMPULSE AND ASSOCIATED MCS WAS MOVING THROUGH ERN SD. AT THE SFC...A WEAK FRONTAL BOUNDARY LINGERED ACROSS SRN WI WHILE A STRONGER COLD FRONT AHEAD OF THE MT SHRTWV EXTENDED FROM NW ONTARIO INTO NRN ND. A WEAK RIDGE EXTENDED FROM QUEBEC ACROSS LAKE SUPERIOR RESULTING IN LIGHT/CALM WINDS OVERNIGHT. AREAS OF FOG...LOCALLY DENSE...HAS DEVELOPED AS ABUNDANT LOW LEVEL MOISTURE LINGERED BELOW AN INVERSION ABOVE 850 MB. EXPECT THAT THE MORNING WILL BE DOMINATED BY LOW CLOUDS BUT WITH DAYTIME HEATING/MIXING THE LOW CLOUDS ACROSS MOST OF THE AREA WILL THIN OUT ENOUGH BY THIS AFTERNOON FOR TEMPERATURES TO CLIMB INTO THE LOWER 80S INLAND. SATELLITE TRENDS...SHORTER TERM MODELS AND CAPE GRADIENT...SUGGEST THAT THE ERN SD MCS WILL TRACK TO THE EAST INTO W AND SRN WI. THERE IS SOME UNCERTAINTY REGARDING THE IMPACTS OF THE MCS ON CONVECTION DEVELOPING FARTHER TO THE NORTH. THE FORCING ASSOCIATED WITH THE APPROACHING NRN PLAINS SHRTWV WITH 100M HEIGHT FALLS AND MODERATE 700-300 QVECTOR CONV WILL ALSO BE STRONGEST TO THE NORTH OF THE CWA. HOWEVER...THE SRN END OF THE SHRTWV SHOULD STILL BE STRONG ENOUGH TO SUPPORT SCT SHRA/TSRA MOVING FROM NW WI INTO WRN UPPER MI THIS AFTERNOON AND THROUGH THE REST OF THE CWA THIS EVENING. EXPECTED MAX TEMPS AND DEWPOINTS INTO THE MID TO UPPER 60S GIVE CAPE VALUES INTO THE 1K-2K J/KG RANGE...GREATEST WEST CENTRAL. 0-6KM BULK SHEAR VALUES IN THE 30-35 KNOT RANGE WILL BE MARGINAL FOR STRONG/SVR ORGANIZED CONVECTION BUT WITH TSRA MOVING THROUGH DURING PEAK HEATING GIVING DCAPE VALUES IN THE 500-1000 J/KG RANGE...SOME ISOLATED STRONG/DAMAGING WIND GUSTS MAY BE POSSIBLE WITH ANY STRONGER STORMS. THE HIGHER PROBABILITIES FOR SVR STORMS REMAINS TO THE SOUTH WHERE THE INSTABILITY IS GREATEST...PER SPC DAY1 OUTLOOK. THE SHRA/TSRA ARE EXPECTED TO PROGRESS THROUGH THE AREA MOVING INTO THE ERN CWA LATE THIS EVENING AND ENDING OVERNIGHT. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 525 AM EDT TUE JUL 9 2013 AFTER A FEW DAYS OF WARM AND ACTIVE WEATHER WITH POCKETS OF HEAVY RAIN OVER MAINLY WESTERN HALF OF CWA...DEVELOPING TROUGHING ALOFT ACROSS THE GREAT LAKES AND SFC HIGH ON THE WESTERN EDGE OF THE TROUGH ALOFT WILL BRING QUIET AND COOLER WEATHER MID TO LATE WEEK. WARMER TEMPERATURES AND INCREASING SHRA/TSRA CHANCES RETURN FOR THE WEEKEND AS UPPER HEIGHTS BECOME MORE ZONAL. OVERALL AGREEMENT THAT BEST CHANCE OF SHRA/TSRA ON WEDNESDAY WILL BE 12-15Z OVER THE FAR EASTERN CWA. STRONGER TSRA STILL POSSIBLE WITH MUCAPE UP TO 800J/KG. BETTER SHOT FOR SVR WILL BE FARTHER SOUTH OVER SOUTHERN WI/NORTHERN IL CLOSER TO WEST-EAST FRONTAL BOUNDARY AND ON NORTHERN GRADIENT OF HIGHER MLCAPES OVR 1000J/KG. ANY CHANCES OF SHRA/TSRA OVER EAST QUICKLY END THROUGH MORNING AS STRONG DEEP LAYER Q-VECTOR DIVERGENCE/SUBSIDENCE SURGES ACROSS UPPER GREAT LAKES. PRESSURE GRADIENT BRIEFLY BECOMES TIGHT BTWN THE EXITING LOW PRESSURE TROUGH AND HIGH PRESSURE BUILDING OVER THE PLAINS. EXPECT BRIEF BUILDING WAVES AND INCREASED SWIM RISK FOR WEDNESDAY OVER THE LK SUPERIOR BEACHES OF ALGER COUNTY AS WINDS WILL BE FROM THE WEST TO NORTHWEST. WINDS/WAVES AND ASSOCIATED HIGHER SWIM RISK SUBSIDES BY LATE AFTN WITH LOSS OF PRESSURE RISES AND TIGHTER PRESSURE GRADIENT. HIGH PRESSURE REMAINS MAIN WEATHER FEATURE FOR THU/FRI. TEMPS MAY DROP INTO THE LOW-MID 40S OVER INTERIOR COOL SPOTS ON THURSDAY NIGHT WITH LGT SOUTHERLY FLOW AS RIDGE AXIS DRIFTS ACROSS. AIRMASS DOES NOT APPEAR TO BE NEARLY COLD OR DRY ENOUGH FOR ANY FROST POTENTIAL. HIGH TEMPS BOTH DAYS SHOULD TOP OUT IN THE MID-UPR 70S AWAY FROM THE GREAT LAKES. MAY EVEN SEE A FEW SPOTS BACK NEAR 80 DEGREES BY THURSDAY. UNCERTAINTY ABOUNDS WITH TIMING AND EXTENT OF NEXT ROUND AND/OR ROUNDS OF SHRA/TSRA THIS WEEKEND INTO NEXT MONDAY. ECMWF NORMALLY LEADS WAY IN TERMS OF VERIFICATION...BUT BOY ARE ITS SOLUTIONS IN THE LAST COUPLE DAYS QUITE INCONSISTENT IN TERMS OF TIMING FOR THE WEEKEND SHRA/TSRA CHANCES. DOES SEEM LIKE ECMWF IS TRENDING TOWARD SLOWER IDEA SHOWN BY GFS FOR ARRIVAL OF PRECIP FRIDAY NIGHT. WILL START TO SHOW TREND OF CHANCE POPS ONLY OVER THE FAR WEST LATE ON FRIDAY NIGHT WHILE IT STAYS MAINLY DRY ELSEWHERE. UPPER HEIGHTS FLATTEN OUT SATURDAY ALLOWING SHORTWAVES AND MID-LEVEL WIND MAX TO SLIDE ACROSS UPPER GREAT LAKES REGION. MAIN SFC LOW WILL BE WELL TO NORTH CLOSER TO SHARPER TROUGH ALOFT...BUT SW LOW-LEVEL FLOW ALONG WITH INCREASING MOISTURE AND BUILDING INSTABILITY JUST UPSTREAM SHOULD RESULT IN AT LEAST A CHANCE OF SHRA/TSRA AHEAD OF SFC-H85 TROUGH THAT MOVES THROUGH BY SUNDAY MORNING. WITH WRLY FLOW ALOFT...FRONT MAY END UP STALLING OUT LATER IN THE WEEKEND PROVIDING A FOCUS FOR ADDITIONAL SHRA/TSRA. FOR MOST PART USED CONSENSUS POPS...BUT DID INCREASE POPS SLIGHTLY OVER THE SOUTH AND EAST CWA CLOSER TO EXPECTED POSITION OF FRONT PER WPC HAND DRAWN SFC PROGS. BASED ON GENERAL S/SW GRADIENT FLOW AHEAD OF FRONT AND H85 TEMPS IN THE MID TEENS...INCREASED TEMPS OVER CONSENSUS GUIDANCE. EXPECT MAX TEMPS FRIDAY THROUGH SUNDAY IN THE MID-UPR 70S TO AS WARM AS MID 80S. IT WILL ALL DEPEND ON EXTENT OF CLOUDS AND SHRA/TSRA. AFTER MIN TEMPS IN THE 40S AND 50S MUCH OF THIS WEEK...READINGS RETURN TO THE WARMER/MUGGIER 60S BY THE WEEKEND. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON) ISSUED AT 116 PM EDT TUE JUL 9 2013 THE MAIN ISSUES DURING THIS TAF PERIOD WILL BE FOCUSED ON TS CHANCES THIS AFTERNOON WITH MVFR TO IFR CONDITIONS DEVELOPING OVERNIGHT. HAVE PLACED VCTS IN THE IWD TAF AT THE BEGINNING OF THE TAF PERIOD WITH THUNDERSTORMS APPROACHING THE AREA FROM THE SOUTH. CURRENT THINKING IS THAT THIS WILL BE THE MAIN AREA OF CONVECTION THIS AFTERNOON...SHIFTING EASTWARD TO SAW BY 21Z. CMX MAY MISS OUT ON MOST OF THE CONVECTION DUE TO LINGERING CLOUD COVER AND GREATER STABILITY. CEILING AND VISIBILITY WILL LOWER THIS EVENING THROUGH MUCH OF TONIGHT AHEAD OF THE APPROACHING COLD FRONT. IT WOULD NOT BE OUT OF THE QUESTION FOR A FEW RUMBLES OF THUNDER NEAR THE IWD AND SAW TAF SITE BEFORE FROPA...BUT DO NOT EXPECT WIDE SPREAD THUNDERSTORM ACTIVITY. ONCE FRONT PASSES CEILINGS AND VISIBILITY WILL IMPROVE TO VFR CONDITIONS NEAR DAY BREAK WEDNESDAY. WINDS MAY BECOME A BIT GUST BEHIND THE COLD FRONT THROUGH THE DAY WEDNESDAY...WITH GUSTS REACHING NEARLY 25 KNOTS. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 359 PM EDT MON JUL 8 2013 DENSE FOG REMAINS A CONCERN ACROSS LAKE SUPERIOR THROUGH TUESDAY MORNING. LIGHT WINDS AND LITTLE AIR MASS MOVEMENT WILL ALLOW FOR THE REDEVELOPMENT OF AREAS OF DENSE FOG OVERNIGHT. CLEARING SKIES FOR TUESDAY MORNING SHOULD ALLOW ENOUGH HEATING TO MIX OUT THE MOST DENSE FOG BY TUESDAY AFTERNOON. PATCHY FOG WILL THEN LINGER INTO WEDNESDAY BEFORE A COLD FRONT BRINGS DRIER AIR FROM WEST TO EAST ACROSS THE LAKE. WINDS SHOULD BE LIGHT AND GENERALLY VARIABLE THROUGH TUESDAY EVENING. THEN...EXPECT WINDS TO VEER TO THE NW AT 15 TO 25 KNOTS...MAINLY ACROSS THE EAST HALF OF THE LAKE...FOR LATE TUESDAY NIGHT THROUGH WEDNESDAY. HIGH PRESSURE WILL THEN BUILD INTO THE AREA THURSDAY THROUGH SATURDAY AND BRING LIGHT WINDS UNDER 15 KNOTS FOR MUCH OF THE TIME PERIOD. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... DENSE FOG ADVISORY UNTIL 5 PM EDT /4 PM CDT/ THIS AFTERNOON FOR LSZ162-240>251-263>267. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...JLA AVIATION...KEC MARINE...KLUBER
AREA FORECAST DISCUSSION
NWS GAYLORD MI
106 PM EDT TUE JUL 9 2013 .SYNOPSIS... ISSUED AT 344 AM EDT TUE JUL 9 2013 THERE WILL BE SMALL CHANCES FOR POP UP SHOWERS AND THUNDERSTORMS TODAY. BETTER CHANCES OF RAINFALL WILL OCCUR TONIGHT INTO WEDNESDAY MORNING AS A COLD FRONT APPROACHES THE REGION. HIGH PRESSURE WILL BEGIN TO BUILD IN BY LATE WEDNESDAY...BRINGING COOLER AND LESS HUMID CONDITIONS FOR MIDWEEK. A WARMING TREND WILL THEN FOLLOW FOR LATE IN THE WEEK INTO THE UPCOMING WEEKEND. && .UPDATE... ISSUED AT 106 PM EDT TUE JUL 9 2013 WELL...HERE WE GO WITH MORE SURPRISES. UPSTREAM CONVECTION IS WELL AHEAD OF SCHEDULE AND IS HOLDING TOGETHER NICELY. MUCAPE VALUES ARE ON THE RISE ACROSS SOUTHWEST PARTS OF THE CWA WHERE SUNSHINE IS BREAKING OUT AND A WARM FRONT IS SLOWLY LIFTING NORTH. BASED ON LATEST HRRR DATA (WHICH IS ITSELF ABOUT 3 HOURS TOO SLOW WITH CURRENT ACTIVITY)...WILL NEED TO PUSH UP ARRIVAL TIME OF PRECIP CHANCES ROUGHLY 20-23C ACROSS THE CWA. WITH THAT SAID...AM A LITTLE LEARY THAT ACTIVITY MAY TEND TO FADE WITH EASTERN EXTENT GIVEN LACK OF INSTABILITY ACROSS NORTHEAST LOWER (LOTS OF REMAINING STRATUS)...BUT THAT`S MORE OF A VERY NEAR TERM ISSUE AS WE START LOOKING AT THE OVERNIGHT FORECAST. SEVERE POTENTIAL VERY LOW AT THIS TIME. UPDATE ISSUED AT 953 AM EDT TUE JUL 9 2013 INTERESTING AND CHALLENGING FORECAST THROUGH LATE AFTERNOON AND EVENING (SOUNDS LIKE THE TYPICAL NORTHERN MICHIGAN TAGLINE DOESN`T IT?)...WITH FORECAST ISSUES CENTERED MAINLY ON CLOUD/FOG/TEMP TRENDS THROUGH MUCH OF THE DAY...BUT SHIFTING TOWARD CONVECTIVE CHANCES BY LATE AFTERNOON AND EVENING. FIRST OF ALL...WILL JUST COME RIGHT OUT AND SAY THAT THIS REMAINS A FAIRLY LOW CONFIDENCE FORECAST WITH REGARD TO ANY CONVECTIVE EVOLUTION LATER TODAY...WITH EVEN LOWER CONFIDENCE ABOUT ANY SEVERE POTENTIAL. HOWEVER...STARTING TO GET THE FEELING CONVECTION MAY TRY TO SNEAK INTO THE PICTURE A LITTLE EARLIER THAN CURRENTLY EXPECTED. MORE ON THAT BELOW...BUT FIRST THINGS FIRST...WE WILL CONTINUE TO DEAL WITH WIDESPREAD STRATUS AND GRADUALLY LIFTING FOG THROUGH AT LEAST LATE MORNING...AND PROBABLY A LITTLE BEYOND. 12Z APX RAOB TELLS THE STORY...WITH A GOOD DEAL OF MOISTURE SANDWICHED BELOW 900MB...AND IN PARTICULAR BELOW 950MB...COURTESY OF A SHALLOW INVERSION AND PLENTIFUL BOUNDARY LAYER MOISTURE FROM YESTERDAY`S MUCH-NEEDED RAINFALL. BASED ON PAST EXPERIENCE...THIS GRUNGE WILL TAKE SOME TIME TO MIX OUT...AND WILL PROBABLY TRANSITION FROM PURE STRATUS TO A THICKER STRATOCU DECK AROUND MIDDAY (WON`T TAKE MUCH TO CONVECTIVELY SATURATE THE 900MB LEVEL PER SOUNDING)...BEFORE ERODING TO SOME DEGREE AS DRIER AIR ABOVE 875 ATTEMPTS TO MIX IN. HOWEVER...SATELLITE ANALYSIS ALREADY SHOWING PLENTY OF THICKER DEBRIS CLOUDS MAKING INROADS THROUGH THE WESTERN LAKES...SO HAVE TO BELIEVE THINGS WILL CLOUD BACK UP FAIRLY QUICKLY ACROSS THE WESTERN CWA THROUGH MID AND LATE AFTERNOON. THIS MAKES TEMPS TRICKY...AND IN GENERAL GUT FEELING SAYS TO LOWER AT LEAST A COUPLE OF DEGREES...THOUGH WITH THE CAVEAT THAT IT DOESN`T TAKE MUCH SUN TO SEND READINGS SOARING THIS TIME OF YEAR. AS FOR PRECIP CHANCES...NOTHING DOING THROUGH AT LEAST 19-21Z...AS STOUT CAPPING AROUND 750MB AND STUBBORNLY SLOW WARMING (AT LEAST INITIALLY) WORK IN TANDEM...COUPLED WITH SUBTLE SHORTWAVE RIDGING ALOFT/NO FORCING. HOWEVER...REALLY WATCHING UPSTREAM CONVECTIVE ACTIVITY...TIED TO A LEADING SHORTWAVE TRAVERSING WESTERN MINNESOTA...OUT AHEAD OF THE MAIN UPPER TROUGH AMPLIFYING INTO THE NORTHERN PLAINS. PER RADAR TRENDS AND SHORT TERM GUIDANCE HINTS...REALLY STARTING TO GET THE FEELING THAT SOME OF THIS ACTIVITY SLIDING EAST FROM NORTHERN IOWA MAY TRY TO IMPACT PARTS OF THE SOUTHERN CWA BY LATE AFTERNOON OR EARLY EVENING. ACTIVITY IS CURRENTLY TRYING TO OUTRUN THE BETTER INSTABILITY...HOWEVER... THIS WON`T BE THE CASE FOR LONG AS STRENGTHENING SOUTHERN FLOW AHEAD OF THE WAVE IS PROGGED TO HELP LIFT A SUBTLE WARM FRONT BACK NORTH INTO CENTRAL WISCONSIN AND EVENTUALLY PARTS OF NORTHERN MICHIGAN. THERE ARE INCREASING HINTS OF BETTER POOLED MOISTURE ALONG THIS BOUNDARY (SEE UPSTREAM DEW POINTS OVER THE SOUTHERN LAKES IN THE LOW 70S)...WHICH COMBINED WITH AT LEAST A LITTLE DAYTIME HEATING AND SUBTLE MID LEVEL HEIGHT FALLS MAY BE ENOUGH TO SUSTAIN THE WARM ADVECTION WING COMPONENT OF THE CURRENT LARGER UPSTREAM MCS. LATEST HRRR GUIDANCE REALLY PICKING UP ON THIS IDEA AND GIVEN CURRENT RADAR MOSAIC...KIND OF HARD TO ARGUE AT THE MOMENT. THIS IS ESPECIALLY TRUE WITH FURTHER HINTS THAT A LOCALIZED LOW LEVEL JET MAXIMUM MAY ALSO POKE INTO THE SOUTHWEST CWA OFF LAKE MICHIGAN...COINCIDENT WITH THE ARRIVAL OF SOMEWHAT BETTER MID LEVEL LAPSE RATES (STILL NOTHING STELLAR) AND BETTER LOW LEVEL THETA-E RIDGING. HAVE RE-WORKED POPS TO SHOW THIS IDEA BETTER. DON`T ANTICIPATE A BIG SEVERE THREAT THROUGH 00Z WITH RATHER SLACK WIND FIELDS (DEEP SHEAR ONLY ABOUT 20 KNOTS) AND LIMITED INSTABILITY (MIXED LAYER CAPE UP AROUND 700 J/KG). UPDATE ISSUED AT 629 AM EDT TUE JUL 9 2013 DENSE FOG HAS EXPANDED OVER THE LAST HOUR OR SO..AND AN SPS HAS BEEN ISSUED FOR LESS THAN A QUARTER OF A MILE VISIBILITIES. THE WORST OF VISIBILITY REDUCTION WAS FOCUSED IN THE COASTAL COMMUNITIES SURROUNDING LAKES MICHIGAN AND HURON. TEMPERATURES WILL BE AT A STAND-STILL FOR THE NEXT SEVERAL HOURS...AS THE STRATUS WILL GO NOWHERE FOR MOST OF THE MORNING. THERE HAVE BEEN NO RAIN SHOWERS FOR THE LAST SEVERAL HOURS...AND NEWER DATA COMING IN...IF ANYTHING...SUGGEST MAYBE EVEN A STRONGER CAP TO PREVENT AFTERNOON SHOWERS AND STORMS. WILL PLAY IT SAFE HERE THOUGH AND KEEP SLIGHT CHANCES IN THE FORECAST...FOR THE MERE FACT THAT WE WILL HAVE DEVELOPED LAKE BREEZES AND A PIECE OF SHORTWAVE ENERGY THAT COULD POSSIBLY OVERCOME CAPPING...ALTHOUGH IT DOESN`T LOOK LIKE IT. BELIEVE THERE WILL BE AFTERNOON SUN...EVENTUALLY FOR TEMPERATURES TO MAKE IT INTO THE 80S....BUT WILL DROP EXPECTED HIGHS A COUPLE DEGREES. && .SHORT TERM...(TODAY THROUGH TONIGHT) ISSUED AT 344 AM EDT TUE JUL 9 2013 CURRENTLY...WEAK LOW PRESSURE WAS WORKING EASTWARD ACROSS NE LOWER...WITH SHOWER ACTIVITY VANISHING AFTER LOSS OF HEATING. MOISTURE HAS BEEN STRIPPED OUT ALOFT AND THE BL REMAINS MOIST. RADIATIONAL COOLING ON TOP OF THIS BL MOISTURE HAS RESULTED IN WIDESPREAD STRATUS...AS FAR OUT AS WISCONSIN. THIS STRATUS WAS ALSO UNDERNEATH A DEVELOPING CAP DUE TO SUBSIDENCE AND SFC HIGH PRESSURE BETWEEN DEPARTING LOW...AND UPSTREAM NEXT LOW PRESSURE AND COLD FRONT. THIS LOW WAS IN FAR NW ONTARIO...WITH ITS COLD FRONT DRAPED DOWN THROUGH NORTH DAKOTA. THERE WAS RELATIVE DRY AIR AND NO PRECIP YESTERDAY WITHIN THE HIGH PRESSURE.TEMPERATURES IN THE STRATUS HAS FLAT-LINED...IN THE UPPER 60S FOR MOST. TODAY...NEW DATA INDICATING THE BL MOISTURE IS QUITE MOIST AND THICK ENOUGH FOR THE SOLID STRATUS TO CONTINUE WELL INTO THE MORNING. WILL KEEP SKIES CLOUDY ALL MORNING...BEFORE HEATING CAN FINALLY RESULT IN HOLES AND A PRETTY GOOD COVERAGE OF CUMULUS. THERE SEEMS TO BE QUITE THE CHANGE IN EXPECTATIONS FOR PRECIPITATION DEVELOPMENT FOR THIS AFTERNOON. A CAP DEVELOPS AT 750MB...VERIFIED BY 00Z UPSTREAM SOUNDINGS ACROSS MINNEAPOLIS/GREEN BAY. USING A PARCEL OF 88/67 WILL RESULT IN ROUGHLY 1400 J/KG SBCAPE AND ONLY A FEW HUNDRED J/KG MLCAPE (WHICH MAY BE BETTER CONSIDERING THE DRYNESS OF THE ENTIRE BL). THUS...CHANCES FOR SEEING ANY SORT OF DIURNAL SHOWERS AND THUNDERSTORMS HAVE DRASTICALLY DWINDLED DUE TO A SIGNIFICANT AMOUNT OF CAPPING/WARM AIR ALOFT. WILL JUST KEEP A 20 PERCENT CHANCE FOR THE LATE AFTERNOON AND EVENING. HIGHS SHOULD MAKE A LATER DAY RUN AT THE MIDDLE AND UPPER 80S. TONIGHT...AFTER ANY DIURNAL CONVECTION WANES...WE WILL BE AWAITING THE MAIN SHOW. THE FAR NRN ONTARIO LOW PRESSURE MOVES EAST AND THE TRAILING COLD FRONT WILL BE MARCHING FROM FAR WESTERN WISCONSIN AND INTO/NEAR EASTERN UPPER/LAKE MICHIGAN BY 12Z. STRONGER SHORTWAVE ENERGY AND NICE UPPER DIVERGENCE SIGNAL WILL WORK IN CONCERT WITH LOW LEVEL CONVERGENCE ASSOCIATED WITH THE FRONT...TO FIRE OFF SHOWERS AND STORMS FOR THE OVERNIGHT. THESE STORMS WILL HAVE BEEN GENERATED ACROSS WISCONSIN IN THE AFTERNOON...BUT EVEN WITH LOSS OF HEATING...THE UPPER FORCING OUGHT TO SUSTAIN THUNDER. MUCAPES ARE PRETTY MINIMAL...IN THE FEW HUNDREDS OR SO...AND WILL DOWNPLAY THE AMOUNT OF THUNDER WITH THE RAIN SHOWERS. THE BETTER/DEEPER INSTABILITY WILL BE WELL SOUTH OF US...IN HIGHER THETA-E AIR ACROSS NRN IL/INDIANA. THE CONVECTION THERE MAY ALSO SERVE TO ROB US OF SOME MOISTURE...ALTHOUGH PWATS ARE EXPECTED TO BE HIGH...1.80" TO ALMOST 2.00" LIQUID. STRATUS AND FOG WILL ALSO BE A CONCERN IN JUICY AIR MASS...BEFORE DRYING SETS IN ON WEDNESDAY. LOWS IN THE MID/UPPER 60S. && .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 344 AM EDT TUE JUL 9 2013 AN UPPER LEVEL TROUGH IN PLACE WEDNESDAY INTO THURSDAY WILL LIFT OUT OF THE REGION AS A LARGE UPPER LEVEL RIDGE CENTERED ACROSS THE DESERT SOUTHWEST EXPANDS NORTHEAST INTO THE GREAT LAKES REGION THURSDAY NIGHT INTO THE WEEKEND. ANOTHER TROUGH MOVING BY TO THE NORTH WILL THEN BEAT DOWN THIS RIDGE EARLY NEXT WEEK. THIS SCENARIO WILL RESULT IN COOLER TEMPERATURES FOR MIDWEEK FOLLOWED BY A WARMING TREND FOR FRIDAY INTO THIS WEEKEND. MEANWHILE...THERE WILL BE MORE CHANCES OF SHOWERS AND THUNDERSTORMS WEDNESDAY...FOLLOWED BY PRECIPITATION FREE WEATHER INTO THE WEEKEND. THERE WILL BE SMALL CHANCES FOR A FEW SHOWERS OR STORMS EARLY NEXT WEEK AS THE TROUGH MOVES BY. THE MAIN LONG TERM FOCUS IS ON LINGERING POPS WEDNESDAY THEN POPS AGAIN NEXT MONDAY. WEDNESDAY...THE SURFACE COLD FRONT CONTINUES TO ADVANCE ACROSS THE REGION FROM NORTHWEST TO SOUTHEAST WITH DRIER AIR ADVECTING IN BEHIND IT. IN ADVANCE OF THE FRONT...THE NAM INDICATES 1000-1500 J/KG OF ML CAPE FROM GAYLORD SE TO GLADWIN THROUGH EARLY AFTERNOON. HOWEVER...THE NAM IS THE MOISTEST MODEL BY FAR WITH THE GFS ET ALL INDICATING LOTS OF DRY AIR ADVECTION (MEAN 1000-500 MB RH FALLING TO ABOUT 40 PERCENT OR SO). THEREFORE WILL LEAVE POPS IN THE CHANCE CATEGORY. POTENTIAL FOR SEVERE STORMS APPEARS LIMITED WITH LIGHT WIND FIELDS ALOFT. HIGHS RANGING FROM AROUND 70 FAR NORTH TO THE LOWER 80S SOUTHEAST. THURSDAY THROUGH MONDAY...THE CORE OF THE UPPER LEVEL COOL POOL IS OVERHEAD (850 MB TEMPS OF PLUS 8 TO 10 C) BUT FAIRLY DRY AIR (MEAN 1000-500 MB RH 30 TO 40 PERCENT) SHOULD INHIBIT DAYTIME HEATING DRIVEN SHOWERS FROM FORMING. OTHERWISE...EXTENDED MODELS CONTINUE TO BE IN GOOD AGREEMENT WITH RIDGING AT THE SURFACE AND SLOWLY BUILDING HEIGHTS ALOFT LEADING TO ANOTHER PLEASANT AND INCREASINGLY WARM STRETCH OF WEATHER INTO THE WEEKEND. AN UPPER LEVEL TROUGH AND ASSOCIATED WEAK COLD FRONT WILL THEN BRING SMALL CHANCES FOR SHOWERS OR THUNDERSTORMS EARLY NEXT WEEK. HIGHS THURSDAY IN THE MIDDLE TO UPPER 70S...FRIDAY IN THE MIDDLE 70S TO LOWER 80S...WITH THE UPPER 70S TO MIDDLE 80S FOR SATURDAY THROUGH MONDAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON) ISSUED AT 106 PM EDT TUE JUL 9 2013 A VARIETY OF CONDITIONS WILL CONTINUE ACROSS THE TAF SITES THROUGH LATE AFTERNOON...WITH THE WORST OF THEM AROUND KAPN WHERE IFR STRATUS WILL GRADUALLY LIFT TO MVFR. WILL BE WATCHING A LINE OF SHOWERS AND STORMS TRYING TO CROSS THE LAKE INTO LATE AFTERNOON...AND SUSPECT THIS FEATURE HAS A GOOD CHANCE OF SURVIVAL...SO HAVE PUSHED UP ARRIVAL TIME BY MANY HOURS...THOUGH WITH PREDOMINANTLY VFR CONDITIONS EXPECTED (OUTSIDE OF SOME LOCAL IFR FOR A FEW MINUTES IN HEAVY RAIN). NOT SURE IF WE WILL BE ABLE TO KICK OFF ANYTHING ELSE OVERNIGHT AS A COLD FRONT APPROACHES...BUT STARTING TO HAVE MY DOUBTS...SO WILL REMOVE ALL PRECIP BY 03-06Z AT THE LATEST. INSTEAD...REMAINING MOIST AIRMASS SHOULD GO INTO MORE FOG/STRATUS PRODUCTION...WITH THE EXPECTATION OF MANY SITES ENDING UP IFR ONCE AGAIN. WINDS WILL BE LIGHT THROUGH MUCH OF THE NIGHT...BUT SHIFT TO THE WEST AND BECOME GUSTY UP TO 25 KNOTS ON WEDNESDAY. && .MARINE... ISSUED AT 344 AM EDT TUE JUL 9 2013 WINDS WILL CONTINUE TO BE VARIABLE AND LIGHT THROUGH TONIGHT UNDER STABLE CONDITIONS ON THE LAKES. UPSTREAM COLD FRONT WILL APPROACH OVERNIGHT AND INTO WEDNESDAY FOR SHOWERS AND STORMS...AND BEHIND THE FRONT WINDS WILL SHIFT TO OUT OF THE NW. MAYBE HAVE SOME ADVISORY LEVEL GUSTS AT PRESQUE ISLE...SSM/ST MARYS. WINDS WILL LIGHTEN UP OVER TIME THEN...AS HIGH PRESSURE GRADUALLY WORKS IN OVER NRN MICHIGAN LATE THIS WORK WEEK...AND THE WEEKEND. && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LH...NONE. LM...NONE. LS...NONE. && $$ UPDATE...LAWRENCE SYNOPSIS...AS SHORT TERM...SD LONG TERM...AS AVIATION...LAWRENCE MARINE...SD
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1236 PM EDT TUE JUL 9 2013 LATEST UPDATE... UPDATE .SYNOPSIS... ISSUED AT 335 AM EDT TUE JUL 9 2013 MOST OF THE DAY TODAY SHOULD SEE A GOOD DEAL OF SUNSHINE AND VERY WARM AND HUMID TEMPERATURES AFTER MORNING LOW CLOUDS AND FOG DISSIPATE. THERE WILL BE A SLIGHT CHANCE OF A STORM DURING THE AFTERNOON HOURS. THE BETTER CHANCE OF MORE WIDESPREAD SHOWERS AND STORMS WILL COME TOWARD AND AFTER MIDNIGHT TONIGHT AS A WAVE OF LOW PRESSURE MOVES THROUGH THE AREA. THE CHANCE OF RAIN WILL DIMINISH THROUGH THE DAY ON WEDNESDAY AS A COLD FRONT PUSHES SOUTH THROUGH THE AREA. TEMPERATURES WILL BE A BIT COOLER WEDNESDAY AFTERNOON. EVEN COOLER TEMPERATURES AND DRY CONDITIONS WILL BE FOUND FOR THE REMAINDER OF THE WEEK BEFORE WE START TO WARM UP AGAIN THIS COMING WEEKEND. && .UPDATE... ISSUED AT 1236 PM EDT TUE JUL 9 2013 I HAVE UPDATED OUR GRIDS TO SPEED UP THE TIMING ON THE CONVECTION ASSOCIATED WITH THE MAIN UPPER WAVE COMING THROUGH THE CWA TO THE 6 PM TO 10 PM TIME FRAME. THIS IS BASED ON TIMING THE WATER VAPOR IMAGE LOOPS...THE TIMING ON THE 12Z NAM...GFS...RAP AND THE HRRR AS FAR OUT AS IT GOES. BASED ON THE WATER VAPOR IMAGE LOOPS THE BACK EDGE GETS TO THE LAKE SHORE BY 8 PM AND THE JACKSON...LANSING...ALAMA AREA BY 10 PM. THIS SUGGESTS THE STORM THREAT WILL BE LARGELY OVER BY 10 PM SO I HAVE LIKELY POPS DURING 6 PM TO 10 PM TIME FRAME BUT HAVE ONLY CHANCE POPS AFTER THAT THROUGH 8 AM WEDNESDAY. IF CURRENT TRENDS CONTINUE I WOULD LOWER THE POPS AFTER MIDNIGHT TO BELOW 20 PERCENT. THE LIFT IN THE DGZ ON THE RAP MODEL CONTINUES TO BE THE BEST FEATURE THAT CORRELATES TO THE LOCATION OF THE LIGHTING TODAY. THAT BRINGS THE MAIN LINE OF STORMS THROUGH THE CWA FROM 8 PM (WEST CWA) TILL 10 PM (EAST CWA). HOWEVER THERE IS THE SUGGESTION THERE COULD BE A FEW STORMS DEVELOPING ON THE WARM FRONT...WEST OF JXN ALONG INTERSTATE 94 BY 4 PM. THOSE STORMS SHOULD HEAD NORTHEAST TOWARD LANSING BY 5 TO 6 PM. MODEL SOUNDING MLCAPES ARE FORECAST TO BE IN THE 1500 TO 3000 J/KG RANGE BUT THE DEEP LAYER SHEAR AHEAD OF THE FRONT IS UNDER 25 KNOTS SO I DO NOT EXPECT AN ORGANIZED SEVERE STORM OUTBREAK WITH THIS....JUST SOME ISOLATED WIND DAMAGE REPORTS. WITH THE FREEZING LEVEL NEAR 15,500 FT AND THE -20 NEAR 26,000 FT... HAIL WOULD BE LESS OF A THREAT BUT THERE IS A FAIR AMOUNT OF CAPE IN THE -10 TO -20C LAYER SO I CAN NOT TOTALLY RULE IT OUT. WITH THE FASTER MOVEMENT OF THE SYSTEM TEMPERATURES MAY NOT GET TO 90 DEGREES AFTER ALL SINCE THE CLOUDS WILL BE MOVING IN SHORTLY (BASED ON VISIBLE AND IR LOOPS). STILL WE SHOULD SEE MID TO UPPER 80S INLAND WITH NO PROBLEM. && .SHORT TERM...(TODAY THROUGH THURSDAY) ISSUED AT 335 AM EDT TUE JUL 9 2013 THE MAIN ISSUE IN THE SHORT TERM IS FOG THIS MORNING...THEN STORM POTENTIAL AND SEVERE THREAT FOR LATE TODAY AND TONIGHT. A FAIR AMOUNT OF FOG AND LOW CLOUDS HAVE DEVELOPED OVER THE NRN SECTION OF THE CWFA EARLY THIS MORNING. SOME OF THIS IS STARTING TO DEVELOP FURTHER SOUTH AS A WEAK SFC TROUGH CRAWLING SOUTH ACROSS THE AREA IS LIKELY BEING OVERRUN A BIT JUST OFF THE SFC AND WITH THE HUMID AIR MASS IN PLACE. WE DO EXPECT THAT THIS WILL DISSIPATE DURING THE MID MORNING HOURS AS THE STRONG SUN ANGLE WORKS ON THE SHALLOW LAYER OF MOISTURE. WE EXPECT TO SEE A GOOD DEAL OF SUNSHINE AFTER THE LOW CLOUDS AND FOG DISSIPATE. THE AREA WILL BE UNDER THE INFLUENCE OF SHORT WAVE RIDGING ALOFT BETWEEN THE DEPARTING WAVE FROM YESTERDAY AND THE NEXT WAVE EXPECTED TONIGHT. FCST SOUNDINGS SHOW A WARM LAYER BETWEEN 850-700MB THAT SHOULD CAP MOST IF NOT ALL CONVECTIVE DEVELOPMENT THROUGH ALMOST 00Z. WE CAN NOT RULE OUT AN ISOLATED SHOWER/STORM DEVELOPING ALONG A BOUNDARY LIKE A LAKE BREEZE. THAT SAID...TH