Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 07/15/12


AREA FORECAST DISCUSSION...UPDATED
NWS RENO NV
454 PM PDT SAT JUL 14 2012 .UPDATE... WENT AHEAD AND PULLED THE THUNDERSTORM CHANCES FOR THE REMAINDER OF THIS AFTERNOON AND EVENING. CUMULUS BUILDUPS IN MONO- MINERAL JUST DON`T HAVE ENOUGH MOISTURE/INSTABILITY TO REALLY GET GOING TODAY. DRY AIRMASS HAS PUSHED THE BULK OF THE MOISTURE INTO EASTERN NEVADA. ALL PUBLIC AND FIRE PRODUCTS HAVE BEEN UPDATED AND SENT. WEB PRODUCTS WILL UPDATE SHORTLY. AS FOR TOMORROW`S FORECAST, WITH THE DRYING THAT WE SAW TODAY, TOMORROW IS LOOKING MUCH LESS PROBABLE FOR THUNDERSTORMS. POPS WILL LIKELY BE TRIMMED BACK FOR SUNDAY, BUT WILL WAIT UNTIL THE 00Z MODEL RUNS TO COME IN BEFORE MAKING ANY BIG CHANGES TO SUNDAY. HOON && .PREVIOUS DISCUSSION... /ISSUED 201 PM PDT SAT JUL 14 2012/ SHORT TERM... CURRENT WATER VAPOR IMAGERY DEPICTS A VERY DRY AIRMASS ALOFT THAT HAS MOVED ACROSS WESTERN NEVADA OVERNIGHT AND THIS MORNING. COMPARED TO YESTERDAY MORNING, THE 12Z OBSERVED PRECIPITABLE WATER AT KRNO DROPPED 0.20 INCHES (TO 0.37 IN). WITH THE DEEPER MOISTURE DISPLACED TO THE EAST, CONVECTION HAS BEEN A LOT SLOWER TO DEVELOP THIS AFTERNOON. BASED ON THE LATEST HRRR FORECAST, VISIBLE SATELLITE AND RADAR TRENDS, DECIDED TO TRIM BACK COVERAGE OF THUNDERSTORMS FOR THIS AFTERNOON AND EVENING. THE BEST CHANCE WILL BE ACROSS MINERAL, EASTERN MONO AND SOUTHEASTERN CHURCHILL COUNTIES WHERE THE LATEST SPC MESOANALYSIS SHOWS MUCAPES OF AROUND 500 J/KG. WITH LITTLE IN THE WAY OF SHEAR, ANY STORMS THAT FORM WILL BE PULSE STORMS THAT WILL SLOWLY DRIFT TO THE EAST-NORTHEAST. ON SUNDAY, THE 12Z GFS/NAM/ECMWF ARE IN GOOD AGREEMENT THAT THE AREA OF LOW PRESSURE OVER CENTRAL OREGON WILL LIFT TO THE NORTHEAST WHILE A WEAK AREA OF LOW PRESSURE DEVELOPS NEAR THE CENTRAL CALIFORNIA COAST. THIS WILL SET UP AN AREA OF DEFORMATION ACROSS THE RENO CWA FROM TAHOE NORTHEAST TO WINNEMUCCA. SOUTH OF THIS BOUNDARY, THE FLOW WILL TURN MORE SOUTHERLY, ALLOWING MONSOON MOISTURE TO BUILD BACK ACROSS SOUTHEASTERN HALF OF THE CWA WITH MODEL PWATS INCREASING TO NEAR 0.75 INCHES. THE EXISTING FORECAST LOOKS GOOD WITH ISOLATED COVERAGE SOUTH OF I-80 AND SCATTERED STORMS SOUTH OF US-50. THE STORMS ACROSS MINERAL AND MONO COUNTIES WILL BE ON THE WET SIDE, WITH WET/DRY HYBRID STORMS CLOSER TO THE MOISTURE BOUNDARY BETWEEN I-80 AND US-50 (SEE THE FIRE WEATHER DISCUSSION BELOW FOR MORE DETAILS). THE WEAKNESS NEAR THE CALIFORNIA COAST WILL WEAKEN ON MONDAY AS A STRONGER AREA OF LOW PRESSURE BUILDS SOUTH ACROSS WESTERN WASHINGTON AND OREGON. THIS WILL TURN THE UPPER LEVEL FLOW BACK TO THE SOUTHWEST, USHERING IN DRIER AIR ACROSS THE RENO CWA. THE BEST CHANCE FOR ANY CONVECTION WILL BE ACROSS MINERAL AND MONO COUNTIES, CLOSER TO THE DEEPER MOISTURE. THE AREA OF LOW PRESSURE WILL CONTINUE TO SLIDE SLOWLY SOUTH ACROSS WESTERN OREGON ON TUESDAY. THIS WILL KEEP DRY SOUTHWEST FLOW IN PLACE. DEPENDING ON THE PLACEMENT OF THE LOW, THERE IS A VERY SMALL CHANCE THAT EXTREME NORTHERN LASSEN COUNTY AND THE SURPRISE VALLEY COULD SEE A PASSING SHOWER ON TUESDAY AFTERNOON SO A SLGT CHANCE WAS INTRODUCED WITH THIS PACKAGE FOR THOSE AREAS. MYRICK LONG TERM...WEDNESDAY THROUGH SATURDAY... A TROUGH LOCATED OVER THE PACIFIC NORTHWEST WILL CREATE A DRY AND STABLE SOUTHWEST FLOW ALOFT WEDNESDAY AND THURSDAY. NUMERICAL GUIDANCE DIFFERS FOR FRIDAY AND SATURDAY...SOME SOLUTIONS BRING THE TROUGH EASTWARD WHILE OTHER SOLUTIONS MOVE IT WESTWARD AND BUILD THE RIDGE OVER THE EASTERN SIERRA AND WESTERN NEVADA. THE OVERALL CONSENSUS IS FOR A DRY FORECAST WITH A WARMING TREND THROUGH SATURDAY...WHICH IS ALREADY COVERED WELL BY THE ONGOING FORECAST. ONE WILD CARD IS THE SLIGHT CHANCE THAT MOISTURE FROM THE REMNANTS OF HURRICANE FABIO COULD BE DRAWN NORTHWARD FRIDAY. TWO RECENT RUNS OF THE GFS ARE THE ONLY ONES SHOWING THIS SOLUTION. WITH FABIO CURRENTLY LOCATED 550 MILES SSW OF THE SOUTHERN TIP OF BAJA-CALIFORNIA CONFIDENCE IS VERY LOW IN THIS SCENARIO. FOR NOW A SLIGHT CHANCE OF THUNDERSTORMS WAS INTRODUCED FRIDAY FOR MONO COUNTY. JCM AVIATION... VFR CONDITIONS WILL PREVAIL OVERALL THROUGH THE WEEKEND AND INTO NEXT WEEK. THUNDERSTORMS ARE POSSIBLE SUNDAY AFTERNOON FROM I-80 SOUTHWARD. IN THE VICINITY OF THESE STORMS THE CIG/VSBYS SHOULD BE AOA 5000/5 WITH GUSTY SFC WINDS. FOR THE TERMINALS ISOLATED STORMS ARE POSSIBLE SUNDAY AFTERNOON AND EARLY EVENING IN THE VICINITIES OF KTRK..KTVL AND KRNO...WITH SOMEWHAT BETTER POTENTIAL FOR THUNDERSTORMS IN THE VICINITY OF KMMH. JCM FIRE WEATHER... HAVE TRIMMED BACK THUNDERSTORM COVERAGE THIS AFTERNOON BASED ON LATEST RADAR AND SATELLITE TRENDS TO ENCOMPASS EASTERN MONO COUNTY INTO MINERAL AND EASTERN CHURCHILL COUNTIES. WITH PLENTY OF MID AND UPPER LEVEL DRY AIR WORKING INTO THE REGION IT HAS SUPPRESSED THUNDERSTORM DEVELOPMENT. TYPICAL AFTERNOON ZEPHYR WINDS CAN BE EXPECTED WITH GUSTS OF 25 TO 30 MPH LATE THIS AFTERNOON AND INTO THE EARLY EVENING. THESE GUSTS WILL CORRESPOND WITH HUMIDITY VALUES AROUND 10-15% WITH LOCALLY CRITICAL CONDITIONS POSSIBLE. HOWEVER, THESE WILL NOT BE WIDESPREAD ENOUGH TO WARRANT ANY RED FLAG WARNINGS TODAY. AFTERNOON WESTERLY WINDS CAN BE EXPECTED AGAIN SUNDAY, BUT WILL BE ABOUT 5 MPH LESS IN SPEED. A PIECE OF ENERGY AND WEAK DEFORMATION BAND WILL HELP TO FOCUS THUNDERSTORM DEVELOPMENT SUNDAY AFTERNOON WITH ISOLATED COVERAGE POSSIBLE BETWEEN INTERSTATE 80 AND HIGHWAY 50 AND SCATTERED COVERAGE SOUTH OF HIGHWAY 50. THE DEEPEST MOISTURE WILL BE SOUTH OF HIGHWAY 50 AND EAST OF HIGHWAY 95, SO STORMS THROUGH THIS AREA WILL BE WET. NORTH AND WEST OF THERE, A HYBRID OF STORMS ARE POSSIBLE WITH THE POTENTIAL FOR A DRY LIGHTNING STRIKE OUTSIDE OF THE WET THUNDERSTORM CORE. THIS COULD START NEW FIRES, BUT WITH THE SMALL AREA OF HYBRID STORMS, AM NOT PLANNING ANY RED FLAG WARNINGS AT THIS TIME. IN ADDITION, WATCHING HOW THE DRY AIR WORKING INTO CALIFORNIA AND WESTERN NEVADA HAS SQUELCHED THUNDERSTORM DEVELOPMENT TODAY, AM A BIT CONCERNED THAT MODELS MAY BE OVERDOING THE CONVECTIVE POTENTIAL SUNDAY AND COVERAGE MAY NEED TO BE TRIMMED A BIT. DF && .REV WATCHES/WARNINGS/ADVISORIES... NV...NONE. CA...NONE. && $$ FOR MORE INFORMATION FROM THE NATIONAL WEATHER SERVICE VISIT... HTTP://WEATHER.GOV/RENO (ALL LOWER CASE)
AREA FORECAST DISCUSSION
NWS SAN JOAQUIN VALLEY - HANFORD CA
1239 PM PDT FRI JUL 13 2012 .SYNOPSIS... INCREASING MONSOON MOISTURE WILL BRING SCATTERED SHOWERS AND THUNDERSTORMS TO THE MOUNTAINS AND DESERT THIS AFTERNOON AND EVENING. THUNDERSTORMS WILL PRODUCE HEAVY RAIN...AND THERE IS THE POTENTIAL FOR FLASH FLOODS. A WEAK SOUTH TO SOUTHWEST FLOW ALOFT OVER THE WEEKEND WILL BRING DECREASING THUNDERSTORM ACTIVITY. && .DISCUSSION... QUICK TEMPERATURE UPDATE FOR THIS AFTERNOON. VALUES IN THE SOUTH END OF THE SJV ARE COMING IN WELL AHEAD OF EXPECTED VALUES AND ACHIEVING BETTER THAN PRACTICALLY ALL DATA WOULD SUGGEST. ON THE OTHER SIDE OF THE MOUNTAINS OUR DESERT AREAS ARE VERY SLOW TO WARM THIS AFTERNOON GIVEN THE HIGH MOISTURE CONTENT OF THE AIR AND GOOD CLOUD COVER. SEEING SOME BREAKS NOW BUT THINK THOSE WILL BE FILLING BACK IN AS THE AFTERNOON PROGRESSES. FLASH FLOOD WATCH STILL LOOKS GOOD. INCREASED HEAT IN THE VALLEY COULD SUPPORT MORE INSTABILITY IN THE NEARBY MOUNTAINS FOR THE REMAINDER OF THE DAYS. LATEST RUNS OF THE HRRR CONTINUE TO POINT TO THE MOUNTAINS OF TULARE AND KERN COUNTIES AS THE FAVORED AREA FOR DEVELOPMENT. && .PREV DISCUSSION... /ISSUED 1005 AM PDT FRI JUL 13 2012/ DISCUSSION... DEEP MOISTURE COVERS THE SE HALF OF OUR CWA ATTM. REGIONAL 13.12Z RAOBS AND LATEST OBJECTIVE ANALYSIS DEPICT PRECIPITABLE WATER VALUES NEAR 2.0 INCHES JUST TO THE SOUTHEAST OF OUR CWA WHICH IS NEAR THE 99TH PERCENTILE FOR THE RAOB SITES. THE PLUME OF ANOMALOUSLY HIGH MOISTURE /PLUS-4 ST DEVS/ WILL BE ORIENTED FROM NORTH TO SOUTH ALONG THE COLORADO RIVER AND UP INTO NV/UT...THE HNX FORECAST AREA WILL BE JUST ON THE WESTERN PERIPHERY OF IT. FEATURES OF NOTE ON SATELLITE IMAGERY INCLUDE THE UPPER LEVEL LOW/POTENTIAL VORTICITY ANOMALY NEAR SAN DIEGO AND THE LARGER LOW MOVING INTO WASHINGTON /WITH AN ASSOCIATED TROUGH DIPPING TOWARD THE CENTRAL CALIFORNIA COAST/. THE 13.12Z NAM APPEARS TO HAVE INITIALIZED EXCEPTIONAL WELL THIS MORNING...WILL BE UTILIZING IT AND HRRR RUNS THROUGH THE DAY. LATEST OBSERVATIONAL AND MODEL DATA SUPPORT OUR AREA OF CONCERN TODAY WILL BE EASTERN FRESNO...TULARE...AND MUCH OF KERN COUNTIES. THIS REGION WILL BE IN THE FAVORED MOISTURE CONVERGENCE AREA OF THE SOUTHERN CALIFORNIA LOW AND WILL ALSO GET SOME MINOR UPPER LEVEL SUPPORT FROM THE INCOMING UPSTREAM TROUGH. INSTABILITY MAY STRUGGLE TO DEVELOP THROUGH THE DAY DUE TO THE INCREASED MOISTURE BUT BY THIS AFTERNOON WE SHOULD SEE MLCAPE VALUES IN THE 500-1000 J/KG RANGE OVER THE SIERRA SOUTH OF KINGS CANYON AND THE TEHACHAPIS. STORM MOTION /CORFIDI VECTORS/ SUPPORT A SLOW SOUTHWARD MOVEMENT OF 5-10 KTS. WITH THIS SCENARIO...THE FLASH FLOOD WATCH CURRENTLY IN EFFECT LOOKS GOOD. EXPECT SOME PRECIPITATION TO CONTINUE INTO THE LATE EVENING/OVERNIGHT HOURS THOUGH THE UPPER LEVEL FORCING AND DEEPEST MOISTURE WILL BE MOVING EAST WITH TIME. TEMPERATURES WILL BE DIFFICULT TODAY AS WELL. MID-LEVEL CLOUDS ARE QUICKLY ERODING WHICH...AFTER A WARM MORNING...WILL ALLOW FOR A WARM AND MUGGY AFTERNOON TO UNFOLD. SHOULD STILL SEE A SEVERAL DEGREE DROP FROM YESTERDAY. && .AVIATION... SCATTERED THUNDERSTORMS ARE LIKELY OVER THE MOUNTAINS AND DESERT THROUGH 18Z SATURDAY WITH ISOLATED THUNDERSTORMS POSSIBLE ALONG THE EAST SIDE AND SOUTH END OF THE SAN JOAQUIN VALLEY AND ADJACENT FOOTHILLS BETWEEN 20Z TODAY AND 06Z SATURDAY. OTHERWISE...VFR CONDITIONS WILL PREVAIL ACROSS THE CENTRAL CALIFORNIA INTERIOR THROUGH 18Z SATURDAY. && .AIR QUALITY ISSUES... ON FRIDAY JULY 13 2012... UNHEALTHY IN FRESNO COUNTY. UNHEALTHY FOR SENSITIVE GROUPS IN KERN... KINGS... MADERA... MERCED AND TULARE COUNTIES AND SEQUOIA NATIONAL PARK AND FOREST. FURTHER INFORMATION IS AVAILABLE AT VALLEYAIR.ORG && .CERTAINTY... THE LEVEL OF CERTAINTY FOR DAYS 1 AND 2 IS MEDIUM. THE LEVEL OF CERTAINTY FOR DAYS 3 THROUGH 7 IS MEDIUM. THIS INFORMATION IS PROVIDED AS PART OF A TRIAL PROJECT CONDUCTED BY THE NATIONAL WEATHER SERVICE SAN JOAQUIN VALLEY - HANFORD. CERTAINTY LEVELS INCLUDE LOW...MEDIUM...AND HIGH. PLEASE VISIT WWW.WEATHER.GOV/HNX/CERTAINTY.PHP FOR ADDITIONAL INFORMATION AND/OR TO PROVIDE FEEDBACK. && .HNX WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH UNTIL 11 PM PDT THIS EVENING CAZ095-097>099. && $$ PUBLIC...INIGUEZ AVN/FW...BEAN SYNOPSIS...BSO WEATHER.GOV/HANFORD
AREA FORECAST DISCUSSION
NWS SAN JOAQUIN VALLEY - HANFORD CA
1005 AM PDT FRI JUL 13 2012 .SYNOPSIS... INCREASING MONSOON MOISTURE WILL BRING SCATTERED SHOWERS AND THUNDERSTORMS TO THE MOUNTAINS AND DESERT THIS AFTERNOON AND EVENING. THUNDERSTORMS WILL PRODUCE HEAVY RAIN...AND THERE IS THE POTENTIAL FOR FLASH FLOODS. A WEAK SOUTH TO SOUTHWEST FLOW ALOFT OVER THE WEEKEND WILL BRING DECREASING THUNDERSTORM ACTIVITY. && .DISCUSSION... DEEP MOISTURE COVERS THE SE HALF OF OUR CWA ATTM. REGIONAL 13.12Z RAOBS AND LATEST OBJECTIVE ANALYSIS DEPICT PRECIPITABLE WATER VALUES NEAR 2.0 INCHES JUST TO THE SOUTHEAST OF OUR CWA WHICH IS NEAR THE 99TH PERCENTILE FOR THE RAOB SITES. THE PLUME OF ANOMALOUSLY HIGH MOISTURE /PLUS-4 ST DEVS/ WILL BE ORIENTED FROM NORTH TO SOUTH ALONG THE COLORADO RIVER AND UP INTO NV/UT...THE HNX FORECAST AREA WILL BE JUST ON THE WESTERN PERIPHERY OF IT. FEATURES OF NOTE ON SATELLITE IMAGERY INCLUDE THE UPPER LEVEL LOW/POTENTIAL VORTICITY ANOMALY NEAR SAN DIEGO AND THE LARGER LOW MOVING INTO WASHINGTON /WITH AN ASSOCIATED TROUGH DIPPING TOWARD THE CENTRAL CALIFORNIA COAST/. THE 13.12Z NAM APPEARS TO HAVE INITIALIZED EXCEPTIONAL WELL THIS MORNING...WILL BE UTILIZING IT AND HRRR RUNS THROUGH THE DAY. LATEST OBSERVATIONAL AND MODEL DATA SUPPORT OUR AREA OF CONCERN TODAY WILL BE EASTERN FRESNO...TULARE...AND MUCH OF KERN COUNTIES. THIS REGION WILL BE IN THE FAVORED MOISTURE CONVERGENCE AREA OF THE SOUTHERN CALIFORNIA LOW AND WILL ALSO GET SOME MINOR UPPER LEVEL SUPPORT FROM THE INCOMING UPSTREAM TROUGH. INSTABILITY MAY STRUGGLE TO DEVELOP THROUGH THE DAY DUE TO THE INCREASED MOISTURE BUT BY THIS AFTERNOON WE SHOULD SEE MLCAPE VALUES IN THE 500-1000 J/KG RANGE OVER THE SIERRA SOUTH OF KINGS CANYON AND THE TEHACHAPIS. STORM MOTION /CORFIDI VECTORS/ SUPPORT A SLOW SOUTHWARD MOVEMENT OF 5-10 KTS. WITH THIS SCENARIO...THE FLASH FLOOD WATCH CURRENTLY IN EFFECT LOOKS GOOD. EXPECT SOME PRECIPITATION TO CONTINUE INTO THE LATE EVENING/OVERNIGHT HOURS THOUGH THE UPPER LEVEL FORCING AND DEEPEST MOISTURE WILL BE MOVING EAST WITH TIME. TEMPERATURES WILL BE DIFFICULT TODAY AS WELL. MID-LEVEL CLOUDS ARE QUICKLY ERODING WHICH...AFTER A WARM MORNING...WILL ALLOW FOR A WARM AND MUGGY AFTERNOON TO UNFOLD. SHOULD STILL SEE A SEVERAL DEGREE DROP FROM YESTERDAY. && .PREV DISCUSSION... /ISSUED 402 AM PDT FRI JUL 13 2012/ DISCUSSION... ANOTHER UPPER TROF WAS LOCATED OVER WESTERN WA...WITH TROF AXIS SAGGING SOUTH ALONG THE WEST COAST. THIS TROF WILL COMPETE WITH THE MONSOON TRAJECTORY THE NEXT 24-48 HRS...BUT EVENTUALLY WILL WIN OUT WITH A DRYING W-SW FLOW GRADUALLY SPREADING OVER CA. THIS WILL MEAN DECREASING TSTM ACTIVITY SAT...AND EVEN LESS SUN. HOWEVER...NOT COMPLETELY CONVINCED ALL TSTM ACTIVITY WILL END AFTER THIS WEEKEND. CLOUDS AND SCT PRECIP WILL BE THE CONTROLLING FACTOR IN TEMPS THE NEXT FEW DAYS. THE OVERALL TREND THRU SUN WILL BE A GRADUAL DOWNTURN IN THE HOT TEMPS...BUT IF ONE DAY IS MORE/OR LESS/ CLOUDY THAN ANOTHER...TEMPS MAY NOT REFLECT THE OVERALL TREND. NIGHTS WILL CONT TO BE WARM WHERE CLOUDS PERSIST...BUT WILL EVENTUALLY COOL OFF AS WEAK ONSHORE FLOW ALOFT KICKS IN...AND THE SJV COMING UNDER INCREASING MARINE INFLUENCE. MODELS IN THE MEDIUM RANGE NOT CONSISTENT IN HANDLING WEST COAST TROF THRU NEXT WEEK...OR PLACEMENT OF LOWEST HEIGHTS. FOR NOW FOLLOWED PERSISTENCE WITH TEMPS AT OR SLIGHTLY LESS THAN NORMAL AND DRY EVERYWHERE. A VERY LOW CONFIDENCE FACTOR IN THE MEDIUM RANGE. && .AVIATION... SCATTERED THUNDERSTORMS ARE LIKELY OVER THE MOUNTAINS AND DESERT THROUGH 18Z SATURDAY WITH ISOLATED THUNDERSTORMS POSSIBLE ALONG THE EAST SIDE AND SOUTH END OF THE SAN JOAQUIN VALLEY AND ADJACENT FOOTHILLS BETWEEN 20Z TODAY AND 06Z SATURDAY. OTHERWISE...VFR CONDITIONS WILL PREVAIL ACROSS THE CENTRAL CALIFORNIA INTERIOR THROUGH 18Z SATURDAY. && .AIR QUALITY ISSUES... ON FRIDAY JULY 13 2012... UNHEALTHY IN FRESNO COUNTY. UNHEALTHY FOR SENSITIVE GROUPS IN KERN... KINGS... MADERA... MERCED AND TULARE COUNTIES AND SEQUOIA NATIONAL PARK AND FOREST. FURTHER INFORMATION IS AVAILABLE AT VALLEYAIR.ORG && .CERTAINTY... THE LEVEL OF CERTAINTY FOR DAYS 1 AND 2 IS MEDIUM. THE LEVEL OF CERTAINTY FOR DAYS 3 THROUGH 7 IS MEDIUM. THIS INFORMATION IS PROVIDED AS PART OF A TRIAL PROJECT CONDUCTED BY THE NATIONAL WEATHER SERVICE SAN JOAQUIN VALLEY - HANFORD. CERTAINTY LEVELS INCLUDE LOW...MEDIUM...AND HIGH. PLEASE VISIT WWW.WEATHER.GOV/HNX/CERTAINTY.PHP FOR ADDITIONAL INFORMATION AND/OR TO PROVIDE FEEDBACK. && .HNX WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH THROUGH THIS EVENING CAZ095-097>099. && $$ PUBLIC...INIGUEZ/BINGHAM AVN/FW...BEAN SYNOPSIS...BSO WEATHER.GOV/HANFORD
AREA FORECAST DISCUSSION
NWS DENVER CO
817 PM MDT SAT JUL 14 2012 .UPDATE... && .SHORT TERM...WEAK CONVECTION IN THE MOUNTAINS CONTINUES TO DIMINISH THIS EVENING WITH ONLY SOME LIGHT ISOLATED RAIN SHOWERS REMAINING WEST OF THE DIVIDE. DRY ON THE PLAINS AS 00Z SOUNDING SHOWED STRONG MID LEVEL STABILITY AT 450MB. .AVIATION...OUTFLOW BOUNDARY HAS SHIFTED SURFACE WINDS TO THE SOUTHWEST AT ALL TERMINALS THIS EVENING. WINDS WILL WEAKEN A BIT AND TURN MORE SOUTHERLY OVERNIGHT. THE BROKEN MID AND HIGH LEVEL DECK OF CLOUDS WILL GRADUALLY THIN OUT LATER TONIGHT. ONLY MINOR TINKERING TO THE WINDS THROUGH TONIGHT. && .PREV DISCUSSION... /ISSUED 343 PM MDT SAT JUL 14 2012/ SHORT TERM...THE UPPER LEVEL RIDGE OVER EASTERN CO TONIGHT WILL CONTINUE TO SLOWLY SHIFT TO THE EAST FOR SUNDAY. AS A RESULT...THE SUBTROPICAL MOISTURE OVER WESTERN CO WILL CONTINUE TO SPREAD EAST INTO THE NORTHEASTERN PLAINS AS WELL. THE LATEST HRRR CONFINES THE DEEP CONVECTION TO THE HIGH COUNTRY TONIGHT. WITH THE RIDGE OVERHEAD IT WILL BE TOO STABLE OVER THE NORTHEAST PLAINS FOR THUNDERSTORMS. WL KEEP ISOLD POPS IN ZONE 38 BUT DROP IT FOR THE REMAINDER THE URBAN CORRIDOR. ON SUNDAY...PRECIPITABLE WATER VALUES CONTINUE TO CLIMB WITH VALUES CLOSE TO ONE INCH IN THE AFTERNOON. FCST CAPES IN THE MOUNTAINS 300-400 J/KG WITH VALUES 800-1100 J/KG OVER THE URBAN CORRIDOR AND NORTHEAST PLAINS. ALTHOUGH IT WILL BE HOT AGAIN SUNDAY AFTN...CLOUD COVER AND THUNDERSTORMS SHOULD INHIBIT HEATING SLIGHTLY IN THE AFTERNOON. LONG TERM...591 RIDGE OVER THE WESTERN GREAT PLAINS CONTINUES ITS SLOW EASTWARD PROGRESSION OVER THE GREAT PLAINS THROUGH MID-WEEK. THE SHIFT ALLOWS SOUTHWESTERLY FLOW ON THE WEST SIDE OF THIS RIDGE TO TRANSPORT INCREASING AMOUNTS OF MOIST SUBTROPICAL AIR UP OVER COLORADO DURING THE FIRST HALF OF THE WEEK. THIS LATEST PLUME OF MONSOONAL MOISTURE LOOKS NEITHER AS MOIST OR AS DEEP AS THE PLUME WE DEALT WITH A WEEK OR SO AGO WHEN STORMS BROUGHT HEAVY RAIN AND RESULTING FLASH FLOODING TO THE FORECAST AREA. THE AXIS OF THE 500-700MB MOISTURE STREAM STARTS OUT OVER THE WESTERN VALLEYS OF COLORADO MONDAY MORNING AND THROUGH THE DAY MODELS SHOW IT SHIFTING EAST OVER THE MTNS AND AND FRONT RANGE FOOTHILLS WITH PRECIPITABLE WATER VALUES UP AROUND 1.25 INCHES OVER THE FRONT RANGE BY LATE IN THE DAY. MODELS ALSO SHOW A WEAK MID-LEVEL SHORTWAVE TROUGH/THERMAL TROUGH EMBEDDED IN THE SOUTHWEST FLOW ALOFT PASSING OVER THE NORTH CENTRAL MTNS IN THE AFTERNOON AND OVER THE NORTHEAST PLAINS MONDAY EVENING WHICH SHOULD FURTHER ENHANCE T-STORM DEVELOPMENT IN THE AREA. HIGH SCATTERED POPS LOOK GOOD FOR NOW FOR THE MTNS AND NEARBY PLAINS...WITH CHANCES FOR PCPN DECREASING FARTHER OUT ACROSS THE PLAINS WHERE THE AIRMAS STILL APPEARS WEAKLY CAPPED. COULD SEE LOCALLY HEAVY RAINFALL FROM STORMS IN AND NEAR THE FRONT RANGE. SHEAR NOT ALL THAT GREAT...SO THE CHANCE FOR SEVERE APPEARS LOW. FOR THE REMAINDER OF THE WEEK...TUESDAY LOOKS TO BE NEARLY AS WET/STORMY AS ON MONDAY WITH THE MONSOON MOISTURE PLUME CONTINUING TO CREEP EASTWARD OVER THE STATE. ONCE AGAIN COULD SEE A FEW LATE STORMS PRODUCING LOCALLY HEAVY RAINFALL...MAINLY OVER AND NEAR THE MTNS. SHOULD ALSO SEE RAIN CHANCES INCREASE ON THE PLAINS WITH INFLUX OF LOW-LEVEL MOISTURE WITH A GUSTY SOUTHEAST FLOW. CAN`T RULE OUT AN ISOLATED SEVERE T-STORM ON THE PLAINS WITH BETTER SHEAR AND INSTABILITY IN PLACE. BY WEDNESDAY...THE MONSOON MOISTURE FLOW APPEARS TO WEAKEN WITH THE UPPER RIDGE OUT EAST WEAKENING SOME. THEREFORE T-STORM CHANCES SHOULD GO DOWN AND WITH MORE SUNSHINE TEMPERATURES WILL BEGIN TO NUDGE UPWARD. THURSDAY AND BEYOND...MEDIUM RANGE MODELS SHOW THE GREAT PLAINS RIDGE STRENGTHENING AGAIN AS IT BEGINS TO BUILD WESTERN TOWARDS THE ROCKY MTN REGION. INCREASE SOUTHERLY FLOW AHEAD OF THIS RIDGE APPEARS TO BRING ANOTHER SURGE OF MOIST SUBTROPICAL AIR UP INTO THE FOUR CORNERS AREA BY WEEK`S END...AND POSSIBLY OVER THE REMAINDER OF COLORADO BY THE WEEK. SO POSSIBLY ANOTHER SHOT FOR DECENT RAINFALL BY END OF THE EXTENDED PERIOD. AVIATION...GUSTY SELY WINDS WILL CONTINUE INTO EARLY EVENING THEN SHIFT TO MORE OF A SOUTHERLY DIRECTION AND DECREASE AFTER 06Z. DO NOT ANTICIPATE TSTMS IN ANY OF THE DENVER TAFS THIS AFTERNOON AND EVENING...WITH BETTER POTENTIAL FOR STORMS SUNDAY AFTN. VFR CONDITIONS WITH NO RESTRICTIONS OVER THE NEXT 18Z HOURS WITH JUST A SLIGHT CHANCE OF STORMS AFTER 20Z SUNDAY. HYDROLOGY...THERE WILL BE A SLIGHT CHANCE OF TSTMS IN THE BURN AREAS UNTIL AROUND 04Z...ALTHOUGH THE THREAT IS LOW...THE STORMS COULD PRODUCE 0.10-0.20 INCHES OF RAINFALL IN 30 MINUTES. INCREASING CHANCE OF TSTMS SUNDAY AFTERNOON WITH A GREATER POTENTIAL FOR BRIEF HEAVY RAINFALL AFTER 20Z SUNDAY. && .BOU WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...ENTREKIN/COOPER LONG TERM....BAKER AVIATION...ENTREKIN/COOPER
AREA FORECAST DISCUSSION
NWS MIAMI FL
144 PM EDT FRI JUL 13 2012 .AVIATION...MOSTLY VFR CONDITIONS EXPECTED AT THE S FL TERMINALS THROUGH THE PERIOD. MODERATE EAST FLOW HAS PUSHED CONVECTION INLAND AWAY FROM THE E CST EXCEPT FOR A FEW SHRA. SCT TSRA WILL CONTINUE TO DEVELOP THROUGH THE AFTERNOON AND MOVE W AND COULD AFFECT THE KAPF TERMINAL UNTIL AROUND 22Z. SPARSE COVERAGE WILL LIMIT THE CHANCES FOR A DIRECT HIT AND HAVE CONTINUED THE VCTS FOR NOW AND WILL AMEND IF NECESSARY. KOB && .PREV DISCUSSION... /ISSUED 903 AM EDT FRI JUL 13 2012/ UPDATE... WATER VAPOR AND VISIBLE SATELLITE FROM THIS MORNING SHOWED A WEAK TROPICAL WAVE ACROSS THE EASTERN GULF WITH SHOWER ACTIVITY OVER THE LOCAL GULF WATERS. ISOLATED TO SCATTERED STREAMER SHOWERS CONTINUED TO MOVE ACROSS THE LOCAL ATLANTIC WATERS AND TOWARD THE EAST COAST. THE 12Z SOUNDING SHOWED PWATS STILL AROUND 2.1 INCHES...WITH DEEP EASTERLY FLOW ACROSS SOUTH FLORIDA. HOWEVER...WATER VAPOR SHOWED DRIER AIR BEGINNING TO MOVE TOWARDS THE EAST COAST OF FLORIDA THIS MORNING...AND FORECAST SOUNDINGS SHOW THIS DRIER AIR MOVING INTO THE REGION THROUGHOUT THE DAY. THIS SHOULD KEEP THE HIGHEST CHANCES OF RAIN FOR THE EAST COAST AREAS IN THE MORNING TO EARLY AFTERNOON HOURS. THE EAST COAST SEA BREEZE WILL MOVE INLAND AND DRIER AIR SHOULD LIMIT ACTIVITY TO JUST A FEW STREAMER SHOWERS BY THE MID AFTERNOON. FOR THE WEST COAST...THE GULF COAST SEA BREEZE IS EXPECTED TO MOVE INLAND THIS AFTERNOON. LOW LEVEL CONVERGENCE AND SEA BREEZE INTERACTIONS WILL LEAD TO NUMEROUS SHOWERS AND THUNDERSTORMS ACROSS THE INTERIOR AND GULF COAST. LIGHTNING PROBABILITIES ARE ALSO VERY HIGH FOR THE GULF COAST AND THE HRRR AND LOCAL WRF SUPPORT THE IDEA OF HIGH RAIN CHANCES FOR THE GULF COAST...ESPECIALLY AFTER 18Z. THE CURRENT FORECAST SUPPORTS THIS THINKING AS WELL...AND THE ONLY CHANGE WAS TO BUMP UP POPS THIS MORNING FOR THE GULF WATERS DOING TO THE ONGOING CONVECTION. PREV DISCUSSION... /ISSUED 740 AM EDT FRI JUL 13 2012/ AVIATION...S FLA WILL BE ON THE EAST SIDE OF A TROPICAL WAVE THAT HAS MOVED INTO THE EASTERN GULF OF MEX. A DEEP MOIST E TO ESE WIND FLOW HAS DEVELOPED. SCATTERED SHRA WITH ISOLD TSRA WILL MOVE W-WNW ACROSS THE ATLC AND ONSHORE. VCSH IN E COAST TERMINALS AND EXPECT BRIEF MVFR CIG/VSBY AS SHRA PASS WILL AMEND AS NECESSARY ESPECIALLY IF A TSRA NEARS ANY ONE TERMINAL. EXPECT TSRA TO DEVELOP OVER THE MAINLAND AFT 14Z AND VCTS 14Z TO 18Z AND EXPECT ACTIVITY TO MOVE INLAND AWAY FROM THE E COAST TERMINALS. AT KAPF...DEVELOPING TSRA INLAND FROM TERMINAL AFTER 18Z WILL MOVE W TOWARD THE GULF AND VCTS AFT 18Z. SURFACE WINDS E COAST CALM TO E-SE < 10 KTS BECOMING 10 TO 15 KTS AFT 14Z. AT KAPF...SURFACE WINDS E < 10 KTS BECOMING SSW-SW AFT 17Z AS WEST COAST SEA BREEZE DEVELOPS. PREV DISCUSSION... /ISSUED 416 AM EDT FRI JUL 13 2012/ DISCUSSION...WATER VAPOR IMAGERY SHOWS RIDGING ALOFT BUILDING INTO SOUTH FL FROM THE NORTHEAST. A MID/UPPER LEVEL LOW SPINNING EAST OF THE BAHAMAS WILL MOVE NORTHWEST TOWARDS THE CAROLINA COAST BY SUNDAY...BUT WITH A TROUGH EXTENDING SW OF THIS FEATURE AND MOVING NW ACROSS SOUTH FL SAT NIGHT-SUN. PWATS WILL SLOWLY DECREASE FROM EAST TO WEST TODAY (BUT STILL AROUND 1.75 EAST COAST THIS AFTERNOON) BEFORE INCREASING BACK TO AROUND 2 INCHES ALONG THIS TROUGH AXIS SAT NIGHT-SUN. IT NEVER DOES BECOME DRY ENOUGH TO PRECLUDE ANYTHING LESS THAN CHANCE POPS. HIGHEST MOISTURE/CONVERGENCE THIS AFTERNOON WILL BE ALONG THE GULF COAST...SO HAVE INCREASED POPS TO LIKELY THERE FOR THIS AFTERNOON. THE WEATHER THROUGH THE WEEKEND WILL FEATURE BEST CHANCES FOR SHOWERS/STORMS ALONG THE ATLANTIC COAST AT NIGHT THEN OVER THE INTERIOR/GULF IN THE AFTERNOON. THE TROUGH SAT NIGHT-SUN COULD ACT TO PRODUCE GOOD CONVERGENCE ALONG A PORTION OF THE ATLANTIC COAST...SO WILL NEED TO WATCH THIS IN LATER MODEL RUNS TO SEE IF POPS MAY NEED TO BE INCREASED. THE WEATHER PATTERN FOR NEXT WEEK WILL FEATURE RIDGING BUILDING INTO SOUTH FLORIDA FROM THE ATLANTIC...AND THIS RIDGE WILL BE STRONGER THAN NORMAL WHICH WILL LEAD TO INCREASING TEMPS ALONG WITH HUMIDITY ESPECIALLY BY THE MIDDLE TO LATER PART OF NEXT WEEK. IMPRESSIVE 500 MB HEIGHTS ARE OVER AFRICA AND INTO THE EASTERN ATLANTIC WITH BOTH GFS/ECMWF SHOWING 500 MB HEIGHTS OF NEAR 600 DECAMETERS EARLY NEXT WEEK. THE STRONG RIDGE WILL GRADUALLY BUILD WESTWARD WITH TIME NEXT WEEK WITH AN INCREASINGLY HOT AIRMASS LOCALLY. GFS/ECMWF SHOW 850 MB TEMPS UP TO 20C BY MID WEEK...SOME +2.5C ABOVE AVG. FOLLOWED CLOSER TO THE MEX/MCX GUIDANCE BEYOND THE SHORT TERM AS OPPOSED TO BIAS CORRECTED GUIDANCE AS THE HOTTER GFS NUMBERS LOOK MORE APPROPRIATE...AND IT COULD END UP HOTTER. HEAT INDICES LIKELY WILL BE IN THE 100-105 RANGE ACROSS SOUTH FL. ALSO...A FORMIDABLE SAHARAN AIR LAYER (SAL) COULD MOVE IN SOMETIME DURING THE MIDDLE TO LATTER PART OF NEXT WEEK. THIS WOULD BRING HAZY SKIES TO THE AREA AND A LESSER COVERAGE OF TSTORMS, THOUGH THEY COULD BE STRONGER GIVEN INCREASED INSTABILITY. WE HAVE DAYS TO SEE HOW STRONG THIS RIDGE WILL BE AND IF A SAL MOVES IN...BUT RIGHT NOW IT LOOKS AS SUCH. MARINE...WINDS WILL REMAIN LIGHT TO MODERATE WITH SEAS OF LESS THAN 4 FEET EXPECTED THROUGH THE PERIOD...SO NO CONCERNS. FIRE WEATHER...NO CONCERNS. && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$
AREA FORECAST DISCUSSION
NWS MIAMI FL
903 AM EDT FRI JUL 13 2012 .UPDATE... WATER VAPOR AND VISIBLE SATELLITE FROM THIS MORNING SHOWED A WEAK TROPICAL WAVE ACROSS THE EASTERN GULF WITH SHOWER ACTIVITY OVER THE LOCAL GULF WATERS. ISOLATED TO SCATTERED STREAMER SHOWERS CONTINUED TO MOVE ACROSS THE LOCAL ATLANTIC WATERS AND TOWARD THE EAST COAST. THE 12Z SOUNDING SHOWED PWATS STILL AROUND 2.1 INCHES...WITH DEEP EASTERLY FLOW ACROSS SOUTH FLORIDA. HOWEVER...WATER VAPOR SHOWED DRIER AIR BEGINNING TO MOVE TOWARDS THE EAST COAST OF FLORIDA THIS MORNING...AND FORECAST SOUNDINGS SHOW THIS DRIER AIR MOVING INTO THE REGION THROUGHOUT THE DAY. THIS SHOULD KEEP THE HIGHEST CHANCES OF RAIN FOR THE EAST COAST AREAS IN THE MORNING TO EARLY AFTERNOON HOURS. THE EAST COAST SEA BREEZE WILL MOVE INLAND AND DRIER AIR SHOULD LIMIT ACTIVITY TO JUST A FEW STREAMER SHOWERS BY THE MID AFTERNOON. FOR THE WEST COAST...THE GULF COAST SEA BREEZE IS EXPECTED TO MOVE INLAND THIS AFTERNOON. LOW LEVEL CONVERGENCE AND SEA BREEZE INTERACTIONS WILL LEAD TO NUMEROUS SHOWERS AND THUNDERSTORMS ACROSS THE INTERIOR AND GULF COAST. LIGHTNING PROBABILITIES ARE ALSO VERY HIGH FOR THE GULF COAST AND THE HRRR AND LOCAL WRF SUPPORT THE IDEA OF HIGH RAIN CHANCES FOR THE GULF COAST...ESPECIALLY AFTER 18Z. THE CURRENT FORECAST SUPPORTS THIS THINKING AS WELL...AND THE ONLY CHANGE WAS TO BUMP UP POPS THIS MORNING FOR THE GULF WATERS DOING TO THE ONGOING CONVECTION. && .PREV DISCUSSION... /ISSUED 740 AM EDT FRI JUL 13 2012/ AVIATION...S FLA WILL BE ON THE EAST SIDE OF A TROPICAL WAVE THAT HAS MOVED INTO THE EASTERN GULF OF MEX. A DEEP MOIST E TO ESE WIND FLOW HAS DEVELOPED. SCATTERED SHRA WITH ISOLD TSRA WILL MOVE W-WNW ACROSS THE ATLC AND ONSHORE. VCSH IN E COAST TERMINALS AND EXPECT BRIEF MVFR CIG/VSBY AS SHRA PASS WILL AMEND AS NECESSARY ESPECIALLY IF A TSRA NEARS ANY ONE TERMINAL. EXPECT TSRA TO DEVELOP OVER THE MAINLAND AFT 14Z AND VCTS 14Z TO 18Z AND EXPECT ACTIVITY TO MOVE INLAND AWAY FROM THE E COAST TERMINALS. AT KAPF...DEVELOPING TSRA INLAND FROM TERMINAL AFTER 18Z WILL MOVE W TOWARD THE GULF AND VCTS AFT 18Z. SURFACE WINDS E COAST CALM TO E-SE < 10 KTS BECOMING 10 TO 15 KTS AFT 14Z. AT KAPF...SURFACE WINDS E < 10 KTS BECOMING SSW-SW AFT 17Z AS WEST COAST SEA BREEZE DEVELOPS. PREV DISCUSSION... /ISSUED 416 AM EDT FRI JUL 13 2012/ DISCUSSION...WATER VAPOR IMAGERY SHOWS RIDGING ALOFT BUILDING INTO SOUTH FL FROM THE NORTHEAST. A MID/UPPER LEVEL LOW SPINNING EAST OF THE BAHAMAS WILL MOVE NORTHWEST TOWARDS THE CAROLINA COAST BY SUNDAY...BUT WITH A TROUGH EXTENDING SW OF THIS FEATURE AND MOVING NW ACROSS SOUTH FL SAT NIGHT-SUN. PWATS WILL SLOWLY DECREASE FROM EAST TO WEST TODAY (BUT STILL AROUND 1.75 EAST COAST THIS AFTERNOON) BEFORE INCREASING BACK TO AROUND 2 INCHES ALONG THIS TROUGH AXIS SAT NIGHT-SUN. IT NEVER DOES BECOME DRY ENOUGH TO PRECLUDE ANYTHING LESS THAN CHANCE POPS. HIGHEST MOISTURE/CONVERGENCE THIS AFTERNOON WILL BE ALONG THE GULF COAST...SO HAVE INCREASED POPS TO LIKELY THERE FOR THIS AFTERNOON. THE WEATHER THROUGH THE WEEKEND WILL FEATURE BEST CHANCES FOR SHOWERS/STORMS ALONG THE ATLANTIC COAST AT NIGHT THEN OVER THE INTERIOR/GULF IN THE AFTERNOON. THE TROUGH SAT NIGHT-SUN COULD ACT TO PRODUCE GOOD CONVERGENCE ALONG A PORTION OF THE ATLANTIC COAST...SO WILL NEED TO WATCH THIS IN LATER MODEL RUNS TO SEE IF POPS MAY NEED TO BE INCREASED. THE WEATHER PATTERN FOR NEXT WEEK WILL FEATURE RIDGING BUILDING INTO SOUTH FLORIDA FROM THE ATLANTIC...AND THIS RIDGE WILL BE STRONGER THAN NORMAL WHICH WILL LEAD TO INCREASING TEMPS ALONG WITH HUMIDITY ESPECIALLY BY THE MIDDLE TO LATER PART OF NEXT WEEK. IMPRESSIVE 500 MB HEIGHTS ARE OVER AFRICA AND INTO THE EASTERN ATLANTIC WITH BOTH GFS/ECMWF SHOWING 500 MB HEIGHTS OF NEAR 600 DECAMETERS EARLY NEXT WEEK. THE STRONG RIDGE WILL GRADUALLY BUILD WESTWARD WITH TIME NEXT WEEK WITH AN INCREASINGLY HOT AIRMASS LOCALLY. GFS/ECMWF SHOW 850 MB TEMPS UP TO 20C BY MID WEEK...SOME +2.5C ABOVE AVG. FOLLOWED CLOSER TO THE MEX/MCX GUIDANCE BEYOND THE SHORT TERM AS OPPOSED TO BIAS CORRECTED GUIDANCE AS THE HOTTER GFS NUMBERS LOOK MORE APPROPRIATE...AND IT COULD END UP HOTTER. HEAT INDICES LIKELY WILL BE IN THE 100-105 RANGE ACROSS SOUTH FL. ALSO...A FORMIDABLE SAHARAN AIR LAYER (SAL) COULD MOVE IN SOMETIME DURING THE MIDDLE TO LATTER PART OF NEXT WEEK. THIS WOULD BRING HAZY SKIES TO THE AREA AND A LESSER COVERAGE OF TSTORMS, THOUGH THEY COULD BE STRONGER GIVEN INCREASED INSTABILITY. WE HAVE DAYS TO SEE HOW STRONG THIS RIDGE WILL BE AND IF A SAL MOVES IN...BUT RIGHT NOW IT LOOKS AS SUCH. MARINE...WINDS WILL REMAIN LIGHT TO MODERATE WITH SEAS OF LESS THAN 4 FEET EXPECTED THROUGH THE PERIOD...SO NO CONCERNS. FIRE WEATHER...NO CONCERNS. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 88 77 88 77 / 40 30 30 30 FORT LAUDERDALE 88 79 89 78 / 40 30 30 40 MIAMI 88 77 89 78 / 40 30 30 40 NAPLES 91 74 93 75 / 60 40 50 20 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ DISCUSSION/MARINE/FIRE...84/AK AVIATION/RADAR...30/KOB
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
ISSUED BY NATIONAL WEATHER SERVICE WILMINGTON NC 304 PM EDT FRI JUL 13 2012 .SYNOPSIS... ATLANTIC HIGH PRESSURE WILL EXPAND ACROSS THE SOUTHEAST STATES THROUGH THE WEEKEND. HIGH PRESSURE WILL BEGIN TO SINK SOUTHWARD BY EARLY NEXT WEEK AS A TROUGH OF LOW PRESSURE DEVELOPS INLAND. && .NEAR TERM /THROUGH TONIGHT/... AS OF 3 PM FRIDAY...CONVECTION ONGOING JUST WEST OF THE SEA BREEZE AS ANTICIPATED...WITH WEAKER SHOWERS STILL ADVECTING ONSHORE DUE TO THE DEEP SE FLOW. LATEST RUC FORECAST PROFILES CONTINUE TO INDICATE 1500 TO 2500 J/KG OF SURFACE BASED CAPE WHICH IS HELPING TO FUEL THE SCATTERED TSTMS TODAY. MOST OF THE ACTIVITY IS NOW WEST OF THE SLOWLY PENETRATING SEA BREEZE...BUT KCLX RADAR STILL INDICATES WEAK SHOWERS ADVECTING INLAND FROM THE OCEAN. EXPECT THIS TO PERSIST AT LEAST UNTIL NIGHTFALL...ALTHOUGH OVERALL COVERAGE AND INTENSITY WILL DECREASE SIGNIFICANTLY WITH LOSS OF HEATING. THE BIGGEST THREAT THROUGH THE REST OF THE EVE WILL BE VERY HEAVY RAINFALL WITH ISOLATED/LOCALIZED FLOODING...MOSTLY WEST OF I-95. TEMPS WILL SLOWLY COOL NEAR THE COAST WITH THE SEA BREEZE...AND LEVEL OUT NEAR 90 WELL INLAND. AFTER NIGHTFALL THERE IS LIKELY TO BE A BREAK IN SHRA/TSRA...BUT RENEWED ACTIVITY WILL DEVELOP ACROSS THE WATERS WHERE COOLING AIR TEMPS WILL HELP FORCE STEEPER LOW LEVEL LAPSE RATES AND INCREASE INSTABILITY. SIMILAR TO LAST NIGHT...SHOWERS WILL WORK TOWARDS THE COAST AND HAVE CONTINUED SCHC TRW- ALONG THE COAST THROUGH THE OVERNIGHT. DO NOTE A BUILDING MID LEVEL CAP DUE TO WESTWARD RETROGRESSION OF MID LEVEL HIGH PRESSURE ACROSS THE ATLANTIC HOWEVER...AND THIS WILL LIMIT INTENSITY AND COVERAGE OF SHOWERS. MINS TONIGHT WILL BE TEMPERED BY CONTINUING SE FLOW AND SOME ENHANCED LOW LEVEL CLOUD COVER. BUFR PROFILES INDICATE THAT 1500-2000 FT STRATUS WILL CREATE A CEILING DURING THE OVERNIGHT...BUT WITH INCREASING DRY AIR ABOVE 850MB EVIDENT...EXPECT THIS WILL BE TRANSIENT IN NATURE...MOSTLY DURING ANY SHOWERS THAT MAY ADVECT ONSHORE. STILL...THIS WILL BE ENOUGH TO LIMIT OVERALL COOLING...AND EXPECT MINS AROUND 73 WELL INLAND TO NEAR 80 AT THE COAST. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... AS OF 3 PM FRIDAY...DEEP ONSHORE BUT RELATIVELY LIGHT WIND FLOW TO PREVAIL OVER THE WEEKEND...BUT BECAUSE BERMUDA HIGH PRESSURE EXPANDS WESTWARD...DRIER MID-LEVEL SUSIDENT AIR INFILTRATES THE COLUMN VIA EASTERLY TRAJECTORIES. DESPITE NOTEWORTHY LOW-LEVEL MOISTURE SATURDAY AND SUNDAY...THIS SOMEWHAT PARCHED AIR ALOFT WILL SERVE TO LIMIT CONVECTIVE COVERAGE OVER THE WEEKEND AND WE HAVE KEPT POP VALUES IN THE ISOLATED TO LOW-END SCATTERED RANGE. THE LOWER PWAT VALUES WILL ALSO LESSEN THE FLOODING POTENTIAL. HAVE TAYLORED POPS TO CORRELATE WITH DIURNAL HEATING AND WE SEE LITTLE UPPER SUPPORT. ONE ITEM OF NOTE. APPEARS A PEICE OR PORTION OF A TROPICAL WAVE APPROACHING FLORIDA MAY INCREASE COASTAL SHOWERS OFF GA/SC. HAVE HELP POPS IN THE ISOLATED-SCT CATEGORY HOWEVER UNTIL WE GET SOME ADDITIONAL RESOLUTION ON THIS APPROACHING FEATURE BY 00Z MONDAY. THE AFTERNOON SEA BREEZE CIRCULATION WILL LIKELY GENERATE SE-ESE 15-20 MPH WINDS GUSTS NEAR SHORE AND ALONG THE COAST AFTERNOONS. THE PATTERN SUPPORTS TEMPERATURES VERY CLOSE TO CLIMATOLOGICAL STANDARDS UPPER 80S COAST AND LOW/MID 90S INLAND...AND MAX TEMPS NEAR THE COAST MAY BE REALIZED IN THE EARLY TO MIDDLE AFTERNOON DUE TO THE SEA BREEZE CIRCUALTION. && .LONG TERM /MONDAY THROUGH FRIDAY/... THIS PERIOD TO BE DOMINATED BY DEEP-LAYER HIGH PRESSURE..THOUGH LOW PRESSURE WILL TRY TO EXERT MORE INFLUENCE BY THE MIDDLE OF NEXT WEEK. OVERALL NO MAJOR CHANGES TO THE PREVIOUS FORECAST WITH MAINLY SCATTERED AFTERNOON/EVENING SHOWERS AND TSTMS. POTENTIALLY THE GREATEST COVERAGE LATE NEXT WEEK AS AN INLAND SURFACE TROUGH DEVELOPS. && .AVIATION /19Z FRIDAY THROUGH WEDNESDAY/... AS OF 19Z...EXPECT MOST OF THE CONVECTION THIS AFTERNOON TO BE INLAND FROM THE TERMINALS...BUT CLOSE ENOUGH FOR THE FIRST COUPLE OF HOURS TO WARRENT A VCSH. A RUMBLE OF THUNDER IS POSSIBLE...BUT MOST OF THE ACTIVITY WILL BE LOW TOPPED...TROPICAL IN NATURE. TONIGHT...SOUTHEAST FLOW WILL PREVAIL THROUGH MOST OF THE TROPOSPHERE WITH EXCELLENT VISIBILITIES EARLY. THERE MAY BE SOME MVFR STRATUS DEVELOPMENT OVERNIGHT IN THE MOIST ENVIRONMENT...AND SOUNDINGS SUGGEST BKN 1500 FT CIGS AT BOTH TERMINALS. HAVE MENTIONED TEMPO MVFR FOR POTENTIAL...MOST LIKELY IN ANY SHOWERS THAT MAY ADVECT ONSHORE DURING THE NIGHT. SATURDAY...CONTINUE SOUTHEAST FLOW. THE ATMOSPHERE WILL BE A BIT DRIER THAN TODAY...NEVERTHELESS AN ISOLATED SHOWER IS POSSIBLE TOWARD THE END OF THE FORECAST PERIOD. EXTENDED AVIATION OUTLOOK...LOW PROBABILITIES OF SUB-VFR CONDS IN MOSTLY AFTERNOON/EVENING SH/TSTMS THROUGH THE MIDDLE OF NEXT WEEK. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 3 PM FRIDAY...AN ONGOING 3FT/8SEC SE SWELL WILL CONTINUE AND BE THE DOMINANT WAVE WITHIN THE SPECTRUM TODAY. LIGHT SE WINDS OF 10-15 KTS WILL CONTRIBUTE LITTLE...SO OVERALL WAVE HEIGHTS WILL BE 2-4 FT...HIGHEST IN THE OUTER PORTIONS OF AMZ374. ADDITIONALLY...WINDS WILL GUST ABOVE 15 KTS NEAR THE COAST DURING THE SEA BREEZE THROUGH THIS EVE WHICH MAY FORCE SLIGHTLY STEEPER WAVE FACES...BUT THE MAJORITY OF THE WATERS WILL SEE A SWELL- DOMINATED SPECTRUM. IN THIS TROPICAL AIRMASS ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE THROUGH THE PERIOD. BRIEFLY HIGHER WINDS/WAVES WITH HEAVY RAIN WILL OCCUR WITHIN ANY OF THESE STORMS...BUT THEY WILL BE QUITE ISOLATED BEFORE INCREASING IN COVERAGE LATE TONIGHT. SATURDAY THROUGH WEDNESDAY...MODERATE SE-ESE WINDS EXPECTED OVER THE WATERS THIS WEEKEND....WITH GUSTS NEAR 20 KT POSSIBLE EACH AFTERNOON ASSOCIATED WITH THE SEA BREEZE CIRCUALTION. SEAS 3 FT OVER THE WEEKEND BUT A FEW 4 FOOTERS MAY PREVAIL SINCE THE SE FLOW IS PERSISTENT AND A DECENT WAVE BUILDER. EXPECT SE WAVES SAT/SUN 3-4 FEET IN 6-8 SECOND INTERVALS. ISOLATED TSTMS ON THE WATERS WLL BE FAVORED OVERNIGHT AND EARLY MORNING WHEN BUOYANCY OVER THE OCEAN IS MAXIMIZED. MARINERS ARE ENCOURGAED TO CONSULT RADAR TRENDS BEFORE HEADING OUT. FOR MONDAY THROUGH WEDNESDAY...NEAR TYPICAL BERMUDA HIGH PRESSURE IN PLACE AND MODERATE S-SW WINDS ARE EXPCETED. WE COULD SEE AN INCREASE IN SW WINDS LATE TUE AS A SURFACE TROUGH AMPLIFIES OVER THE CAROLINA INTERIOR...AGAINST BERMUDA HIGH PRESSURE OFFSHORE. THIS COULD BRING SUSTAINED WINDS NEAR 20 KNOTS TUE AFTERNOON INTO WEDNESDAY. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...NONE. && $$ NEAR TERM...JDW SHORT TERM...MJC LONG TERM...SHK AVIATION...HDL/JDW
AREA FORECAST DISCUSSION
NWS POCATELLO ID
101 PM MDT FRI JUL 13 2012 .SHORT TERM...UPPER FLOW FROM THE SOUTH TODAY IS BRINGING A LARGE PLUME OF MONSOON MOISTURE THRU THE GREAT BASIN INTO ID. WIDESPREAD SHOWERS AND A FEW TSTMS ARE MOVING THRU THE MAGIC VALLEY INTO THE CENTRAL MTNS...WITH ISOLD SHOWERS ELSEWHERE. MODELS HAVING SOME DIFFICULTY AGREEING ON A SOLUTION TONIGHT AND SATURDAY. BOTH THE GFS AND NAM HAVE BEEN UP AND DOWN ON PRECIP CHANCES. THE NAM IS NOT INITIALIZING AT ALL WELL WITH THE LOCATION PRECIP SO FAR... AND THE GFS IS NOT MUCH BETTER. THE HRRR IS DOING QUITE WELL SO FAR...BUT ONLY GOES OUT TO EARLY THIS EVENING. IT DOES SHOW A RATHER LARGE AREA OF PRECIP MOVING NORTH FROM UT BY EARLY EVE. THIS IS CONSISTENT WITH THE CURRENT FCST THINKING...SO WILL STAY THE COURSE AND GO WITH INCREASING CHANCES FOR PRECIP TONIGHT AND STAYING ON THE HIGH SIDE FOR SATURDAY. A LOOK AT MODEL SOUNDINGS SHOW THE AIRMASS MOISTENING UP AT ALL LEVELS...SO MEASURABLE RAINFALL AMOUNTS APPEAR LIKELY. THE PRECIP AND CLOUD COVER WILL KEEP TEMPS ON THE COOL SIDE...SO ONLY EXPECTING ISOLD TO WIDELY SCATTERED TSTMS EMBEDDED WITH THE SHOWERS THRU SATURDAY. BY SUNDAY ...A SMALL UPPER LOW DROPS INTO NW WA. A SMALL NORTHERN STREAM TROF ROTATES THRU FOR MORE SHOWERS AND TSTMS ON SUNDAY. .LONG TERM...THE UPPER LOW MIGRATES FROM NW WA TO SW OR BY MON NIGHT... AND STAYS PUT THRU WED. THIS WILL PUSH DRIER AIR INTO THE REGION AND RESULT IN ISOLD TO WIDELY SCATTERED TSTMS MAINLY IN THE MTNS THRU THE END OF THE WEEK. TEMPS WILL CLIMB BACK TO NORMAL READINGS NEXT WEEK. HEDGES && .AVIATION...A STEADY STREAM OF MOISTURE WILL CONTINUE TO FLOW INTO THE AREA THROUGH THE NEXT 24 TO 36 HOURS. SHOWERS...AND PERHAPS AN ISOLATED THUNDERSTORM...ARE EXPECTED AT THE TERMINALS STARTING THIS EVENING. MOS GUIDANCE MAY BE OVERDONE ON THE TS PROBABILITIES AS MORE CLOUD COVER SHOULD CURTAIL MUCH OF THE CONVECTIVE ACTIVITY. HINSBERGER && .FIRE WEATHER...MONSOONAL MOISTURE WILL CONTINUE STREAMING INTO IDAHO THROUGH THE WEEKEND LEADING TO INCREASED CHANCES OF A WETTING RAINFALL. THUNDERSTORM POTENTIAL IS THE GREATEST AT THE LEADING EDGE OF THE TROPICAL MOISTURE AND WILL THUS KEEP RED FLAG WARNING FOR THE CENTRAL MOUNTAINS AND EASTERN HIGHLANDS BELOW 6500 FT. NO RED FLAG HEADLINES ARE BEING CONSIDERED AT THE MOMENT FOR THE WEEKEND AS LIGHTNING ACTIVITY SHOULD WANE DUE TO THE LACK OF SURFACE HEATING...BUT SOME ISOLATED THUNDERSTORMS MAY OCCUR IF LIFT FROM THE UPPER TROUGH IN OR/WA IS STRONG ENOUGH. HUMIDITY BEGINS TO DECREASE GRADUALLY STARTING EARLY NEXT WEEK AND TEMPERATURES SHOULD ALSO GRADUALLY RISE. HINSBERGER && .PIH WATCHES/WARNINGS/ADVISORIES... RED FLAG WARNING UNTIL 11 PM MDT THIS EVENING BELOW 6500 FEET FOR THE IDZ411-476-477. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1005 PM CDT SAT JUL 14 2012 .DISCUSSION... 837 PM CDT CONVECTIVE ACTIVITY HAS SETTLED THIS EVENING AND SHOULD BE DRY THROUGH THE REMAINDER OF THE EVENING. HAVE TWEAKED POPS TO REFLECT DIMINISHED CHANCES. LATE TONIGHT ANOTHER MID LEVEL DISTURBANCE IS EXPECTED TO DROP SOUTH ACROSS THE AREA. ISOLATED THUNDERSTORMS ASSOCIATED WITH THIS WAVE HAVE ALREADY DEVELOPED OVER PORTIONS OF WISCONSIN...BUT OVERALL FORCING/MOISTURE CONVERGENCE APPEARS TO BE VERY WEAK AND DO NOT EXPECT MORE THAN ISOLATED COVERAGE IF ANY AS IT MOVES INTO NORTHERN ILLINOIS. OTHERWISE...ONLY MADE MINOR TWEAKS TO HOURLY TRENDS FOR T/TD...OVERALL FORECAST APPEARS ON TRACK. BMD //PREV DISCUSSION... 210 PM CDT CONCERNS WITH THE FORECAST ARE CENTERED ON CONVECTION THROUGH THIS EVENING...AND THEN HOT TEMPERATURES THE NEXT SEVERAL DAYS. SHORT TERM...REST OF THIS AFTERNOON THROUGH SUNDAY... TOWERING CUMULUS ALONG WITH SOME SCATTERED STORMS HAVE DEVELOPED EARLY THIS AFTERNOON ACROSS MAINLY THE EASTERN HALF OF THE FORECAST AREA ALONG AND AHEAD OF A SHEARED OUT UPPER IMPULSE AND AN ELEVATED /850-700MB/ WIND AND MOISTURE CONVERGENCE ZONE. GIVEN A FAIRLY UNSTABLE AIR MASS PER MODIFIED AMDAR SOUNDINGS AND RAP ANALYSIS...WITH MLCAPE VALUES OF 1000 TO 1500 J/KG...THESE STORMS SHOULD CONTINUE TO REGENERATE WITH THE FURTHER FOCI OF BOUNDARY INTERACTIONS. HAVE ALREADY SEEN THE DIVERGENT VELOCITY SIGNATURES ON RADAR UNDERNEATH THESE STORMS WITHIN JUST TWO RADAR VCPS...SHOWING THE DOWNDRAFT POTENTIAL ONCE AGAIN. ENVIRONMENTAL DCAPE VALUES ANALYZED BY THE RAP OF 700 TO 1000 J/KG ARE SLIGHTLY LESS THAN YESTERDAY...BUT SUFFICIENT ENOUGH FOR A POSSIBLE ISOLATED SEVERE GUST...INCLUDING IN NEARSHORE AREAS OF THE LAKE IN ANY STORMS THAT DRIFT NORTHEAST OVER THAT AREA. AN UPPER LEVEL SHORT WAVE...AS PART OF THE LARGER BROAD TROUGH...IS MOVING SOUTHEAST ACROSS WESTERN WI EARLY THIS AFTERNOON. THE INITIAL SURFACE BOUNDARY UNDERNEATH THIS IS HELPING TO FOCUS SOME SCATTERED STORMS...WITH SIMILAR ML INSTABILITY OF 1000 TO 1500 J/KG. MORE DEVELOPMENT IS ANTICIPATED THROUGH EARLY EVENING IN ADVANCE OF THIS AS CONVERGENCE IMPROVES...AND SOME OF THIS MAY POTENTIALLY BE ALONG OUTFLOW THAT IS ALREADY INTO NORTHWEST IL. EXPLICIT CONVECTIVE MODELS DO KEY IN ON SCATTERED STORM DEVELOPMENT TOWARD THE I-39 CORRIDOR BY LATE AFTERNOON. WITH THE SHORT WAVE AND FRONTAL APPROACH...ALONG WITH DEEP LAYER SHEAR VALUES OF SEMI-DECENT 30 KT PROJECTED...THESE SHOWERS AND STORMS HAVE POTENTIAL TO HANG ON LATER INTO THE EVENING. THE COOL FRONT WILL MOVE THROUGH THE AREA LATE TONIGHT AND SUNDAY MORNING...BUT WASHING OUT AS IT DOES. TEMPERATURES ON SUNDAY ARE ACTUALLY EXPECTED TO BE SLIGHTLY HIGHER THAN TODAY...AND DEW POINTS SHOULD BE CLOSE. THIS WILL AGAIN PROVIDE MODEST INSTABILITY...BUT HEIGHT RISES ALOFT SHOULD TEMPER STORM DEVELOPMENT. A ROGUE LATE AFTERNOON CELL OR TWO CANNOT BE RULED OUT ALONG WEAK SURFACE CONVERGENCE...BUT HAVE NOT MENTIONED IN THE FORECAST AT THIS TIME. HIGHS ON SUNDAY LOOK TO TOP OUT IN THE LOWER TO MID 90S...WITH A LAKE BREEZE PROVIDING SOME COOLING FOR DOWNTOWN CHICAGO AND NEARBY AREAS DURING THE AFTERNOON. THESE LAKE SHORE AREAS STILL MAY REACH 90 OR NEAR IT BEFORE THE LAKE BREEZE PUSHES THROUGH. MTF LONG TERM...SUNDAY NIGHT THROUGH SATURDAY... THE UPPER LEVEL RIDGE REESTABLISHES ITSELF ACROSS THE CENTRAL US AS THE TROUGH MOVES OFF TOWARD THE NEW ENGLAND AREA. A WEAKENING AREA OF LOW PRESSURE MOVES NORTH OF THE GREAT LAKES MONDAY NIGHT...WHILE ITS COLD FRONT SINKS SOUTH DOWN THE LAKE ON TUESDAY. PRECIP CHANCES DIMINISH AS THE TROUGH DRIFTS EASTWARD SUNDAY NIGHT. THE BEST CHANCE OF PRECIP IN THE EXTENDED IS ALONG THE COLD FRONT LATE TUESDAY THROUGH WEDNESDAY. GUIDANCE DIFFERS ON THE SPEED OF THE FRONT...WITH THE GFS BRINGING THE FRONT THROUGH MUCH FASTER THAN THE ECMWF. GIVEN ISSUES WITH THE GFS LATELY...AND THE ECMWF HAVING VERY CONSISTENT TIMING OVER THE PAST FEW DAYS...GOING WITH THE SLOWER SOLUTION. BOTH MODELS INDICATE MOISTURE WILL POOL ALONG THE FRONT...BUT THEN DISSIPATE AS THE FRONT ENTERS NORTHERN IL. THEREFORE...KEPT BEST PRECIP CHANCES NORTH OF I-80. LIMITED ACTUAL PRECIP CHANCES TO LESS THAN 50 PERCENT GIVEN THE MODEL TRENDS AND DRY CONDITIONS. HIGH PRESSURE BUILDS IN BEHIND THE FRONT...AND GUIDANCE SUGGESTS RANDOM PERIODS OF PRECIP DURING THE LATTER HALF OF NEXT WEEK. HOWEVER...WITH NO CLEAR SOURCE OF FORCING...QUESTIONABLE MOISTURE SOURCES...AND DROUGHT CONDITIONS...DECIDED TO KEEP THE REMAINDER OF THE EXTENDED DRY. AT THIS POINT THE BIGGER CRIME IS GETTING FOLKS HOPES UP FOR RAIN ONLY TO DISAPPOINT. HEAT BUILDS ACROSS THE REGION THROUGH TUESDAY. GUIDANCE SUGGESTS THERE WILL ONLY BE A SMALL PUSH OF SLIGHTLY COOLER AIR BEHIND THE FRONT...WITH WEDNESDAY LOOKING TO BE A BIT COOLER. HOWEVER 850 HPA TEMPS BEGIN TO WARM ALMOST IMMEDIATELY WITH THE UPPER LEVEL RIDGE SW OF THE CWA. THEREFORE...THE LATTER HALF OF NEXT WEEK LOOKS ABOVE AVERAGE. JEE && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 03Z... * LIGHT SOUTH WIND BECOMING SOUTHWEST OVERNIGHT. * VERY LOW PROBABILITY SHRA/TSRA POTENTIAL LATER TONIGHT INTO SUNDAY MORNING. * WIND SHIFT FROM LIGHT WEST-SOUTHWEST TO EAST-NORTHEAST WITH WEAK TROUGH PASSAGE MID-LATE SUNDAY MORNING AND LAKE BREEZE PUSH FROM THE EAST SUNDAY AFTERNOON. RATZER //DISCUSSION...UPDATED 00Z... A WEAK AREA OF LOW PRESSURE WAS OVER LAKE SUPERIOR EARLY THIS EVENING...WITH A TROUGH EXTENDING SOUTH-SOUTHWEST ACROSS WISCONSIN INTO WEST CENTRAL IOWA. ISOLATED THUNDERSTORMS WHICH HAD FORMED ACROSS THE CHICAGO AREA EARLIER HAVE DISSIPATED...WHILE A FEW ISOLATED STORMS REMAIN SOUTH OF THE TERMINALS ALONG AN APPROXIMATELY IKK-BMI-SPI LINE WHERE AN OUTFLOW BOUNDARY FROM OVERNIGHT CONVECTION HAD TAKEN RESIDENCE. ALL OF THIS ACTIVITY SHOULD CONTINUE TO FADE THIS EVENING WITH THE LOSS OF DIURNAL HEATING AND INSTABILITY. WINDS...WHICH HAD BECOME SOMEWHAT CHAOTIC WITH EARLIER LAKE BREEZE AND CONVECTIVE OUTFLOWS ACROSS METRO TERMINALS WERE RETURNING TO A SOUTH-SOUTHEAST DIRECTION AS OF 23Z AND SHOULD CONTINUE TO VEER SOUTHWEST THROUGH LATE EVENING. SPEEDS WILL REMAIN LESS THAN 10 KTS IN THE WEAK PRESSURE GRADIENT IN PLACE ACROSS THE REGION. FORECAST CONCERNS THEN SHIFT TO LOW PROBABILITY POTENTIAL FOR DEVELOPMENT OF ISOLATED TSRA AGAIN LATER TONIGHT INTO SUNDAY MORNING AS MID-LEVEL SHORT WAVE DIGS ACROSS THE UPPER MIDWEST AND WEAK SURFACE TROUGH OVER WI/IA GRADUALLY SAGS ACROSS THE AREA THROUGH SUNDAY. WEAK BUT PERSISTENT LIFT AND MOIST/WARM ADVECTION AHEAD OF THE MID LEVEL WAVE IS EXPECTED TO CONTINUE...WITH FORECAST SOUNDINGS INDICATING SOME MOISTENING AROUND THE 800 MB/6000 FT LEVEL DURING THE AFTER MIDNIGHT HOURS. WHILE MID/UPPER LEVEL TEMPS REMAIN RELATIVELY WARM...THIS DOES INDICATE THE POTENTIAL FOR DEVELOPMENT OF ISOLATED SHRA/TSRA DURING THE PRE-DAWN HOURS SIMILAR TO LAST NIGHT. MOST OF THE HIGH-RES EXPLICIT CONVECTION MODEL GUIDANCE DOES NOT DEVELOP SUCH CONVECTION... THOUGH THERE IS SOME SUPPORT IN THE SHORT-RANGE ENSEMBLE GUIDANCE. OVERALL HOWEVER...PROBABILITY AND CONFIDENCE IS TOO LOW TO INCLUDE IN POINT TAF PRODUCTS SO HAVE LIMITED FORECAST MENTION TO DEVELOPMENT OF A BROKEN VFR DECK AROUND 6000 FT. BETTER WARM/MOIST ADVECTION THEN SHIFTS NORTHEAST/EAST OF THE TERMINALS SUNDAY MORNING. SOME POTENTIAL EXISTS FOR ISOLATED TSRA/SHRA DEVELOPMENT THROUGH THE MORNING AS WEAK SURFACE TROUGH SAGS ACROSS AREA...THOUGH LIGHT WINDS AND RELATIVELY WARM MID-LEVEL TEMPS CONTINUE TO ARGUE AGAINST A SIGNIFICANT THREAT. WITH SURFACE BOUNDARY SAGGING ACROSS THE TERMINALS DURING THE MID- LATE MORNING HOURS...LIGHT SOUTHWEST-WEST WINDS ARE EXPECTED TO SHIFT NORTH. HOWEVER...GRADIENT IS VERY WEAK AND WINDS WILL LIKELY BECOME MORE VARIABLE. THIS WILL ALLOW EASTERLY LAKE BREEZE TO DEVELOP ACROSS CHICAGO SITES DURING THE EARLY-MID AFTERNOON HOURS. RATZER //ORD AND MDW CONFIDENCE...UPDATED 03Z... * HIGH CONFIDENCE IN OVERALL WIND TRENDS. * MEDIUM-HIGH CONFIDENCE IN NO ADDITIONAL TSRA AT TERMINALS. * HIGH CONFIDENCE IN LAKE BREEZE OCCURRENCE SUNDAY. RATZER //OUTLOOK FOR ORD/MDW FOR 12Z MONDAY-12Z SATURDAY...UPDATED 00Z... MONDAY...VFR. TUESDAY...VFR. CHANCE TSRA TUES NGT. WEDNESDAY...SLGT CHANCE TSRA. OTHERWISE VFR. THURSDAY AND FRIDAY...VFR. RATZER && .MARINE... 145 PM CDT LOW PRESSURE ACROSS LAKE SUPERIOR WILL CONTINUE TO MOVE EAST THROUGH SUNDAY. THIS WILL STEER A COOL FRONT ACROSS THE LAKE LATE TONIGHT. AHEAD OF THIS WILL BE SOME SCATTERED STORMS...SOME OF WHICH ARE LIKELY TO BE GUSTY BASED ON THE ENVIRONMENT. THESE WILL BE MOST FAVORED ACROSS THE SOUTHERN THIRD OF THE LAKE INCLUDING NEAR SHORE AREAS OF IL...IN...AND SOUTHWEST MI. WINDS BEHIND THE FRONT ON SUNDAY WILL BECOME LIGHT AND BEGIN TURNING BACK TO SOUTHERLY ALREADY BY AFTERNOON. SOUTHWEST WINDS WILL INCREASE ON MON...WITH OPEN WATER LOCATIONS ACROSS THE NORTH LIKELY REACHING 30 KT DURING MON NIGHT. A COOL FRONT WILL SLOWLY WORK SOUTH ACROSS THE LAKE ON TUESDAY AND TUESDAY NIGHT. THIS WILL SHIFT WINDS TO THE NORTH AND PROVIDE A FOCUS FOR SCATTERED THUNDERSTORMS ONCE AGAIN. MTF && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
838 PM CDT SAT JUL 14 2012 .DISCUSSION... 837 PM CDT CONVECTIVE ACTIVITY HAS SETTLED THIS EVENING AND SHOULD BE DRY THROUGH THE REMAINDER OF THE EVENING. HAVE TWEAKED POPS TO REFLECT DIMINISHED CHANCES. LATE TONIGHT ANOTHER MID LEVEL DISTURBANCE IS EXPECTED TO DROP SOUTH ACROSS THE AREA. ISOLATED THUNDERSTORMS ASSOCIATED WITH THIS WAVE HAVE ALREADY DEVELOPED OVER PORTIONS OF WISCONSIN...BUT OVERALL FORCING/MOISTURE CONVERGENCE APPEARS TO BE VERY WEAK AND DO NOT EXPECT MORE THAN ISOLATED COVERAGE IF ANY AS IT MOVES INTO NORTHERN ILLINOIS. OTHERWISE...ONLY MADE MINOR TWEAKS TO HOURLY TRENDS FOR T/TD...OVERALL FORECAST APPEARS ON TRACK. BMD && .PREV DISCUSSION... 210 PM CDT CONCERNS WITH THE FORECAST ARE CENTERED ON CONVECTION THROUGH THIS EVENING...AND THEN HOT TEMPERATURES THE NEXT SEVERAL DAYS. SHORT TERM...REST OF THIS AFTERNOON THROUGH SUNDAY... TOWERING CUMULUS ALONG WITH SOME SCATTERED STORMS HAVE DEVELOPED EARLY THIS AFTERNOON ACROSS MAINLY THE EASTERN HALF OF THE FORECAST AREA ALONG AND AHEAD OF A SHEARED OUT UPPER IMPULSE AND AN ELEVATED /850-700MB/ WIND AND MOISTURE CONVERGENCE ZONE. GIVEN A FAIRLY UNSTABLE AIR MASS PER MODIFIED AMDAR SOUNDINGS AND RAP ANALYSIS...WITH MLCAPE VALUES OF 1000 TO 1500 J/KG...THESE STORMS SHOULD CONTINUE TO REGENERATE WITH THE FURTHER FOCI OF BOUNDARY INTERACTIONS. HAVE ALREADY SEEN THE DIVERGENT VELOCITY SIGNATURES ON RADAR UNDERNEATH THESE STORMS WITHIN JUST TWO RADAR VCPS...SHOWING THE DOWNDRAFT POTENTIAL ONCE AGAIN. ENVIRONMENTAL DCAPE VALUES ANALYZED BY THE RAP OF 700 TO 1000 J/KG ARE SLIGHTLY LESS THAN YESTERDAY...BUT SUFFICIENT ENOUGH FOR A POSSIBLE ISOLATED SEVERE GUST...INCLUDING IN NEARSHORE AREAS OF THE LAKE IN ANY STORMS THAT DRIFT NORTHEAST OVER THAT AREA. AN UPPER LEVEL SHORT WAVE...AS PART OF THE LARGER BROAD TROUGH...IS MOVING SOUTHEAST ACROSS WESTERN WI EARLY THIS AFTERNOON. THE INITIAL SURFACE BOUNDARY UNDERNEATH THIS IS HELPING TO FOCUS SOME SCATTERED STORMS...WITH SIMILAR ML INSTABILITY OF 1000 TO 1500 J/KG. MORE DEVELOPMENT IS ANTICIPATED THROUGH EARLY EVENING IN ADVANCE OF THIS AS CONVERGENCE IMPROVES...AND SOME OF THIS MAY POTENTIALLY BE ALONG OUTFLOW THAT IS ALREADY INTO NORTHWEST IL. EXPLICIT CONVECTIVE MODELS DO KEY IN ON SCATTERED STORM DEVELOPMENT TOWARD THE I-39 CORRIDOR BY LATE AFTERNOON. WITH THE SHORT WAVE AND FRONTAL APPROACH...ALONG WITH DEEP LAYER SHEAR VALUES OF SEMI-DECENT 30 KT PROJECTED...THESE SHOWERS AND STORMS HAVE POTENTIAL TO HANG ON LATER INTO THE EVENING. THE COOL FRONT WILL MOVE THROUGH THE AREA LATE TONIGHT AND SUNDAY MORNING...BUT WASHING OUT AS IT DOES. TEMPERATURES ON SUNDAY ARE ACTUALLY EXPECTED TO BE SLIGHTLY HIGHER THAN TODAY...AND DEW POINTS SHOULD BE CLOSE. THIS WILL AGAIN PROVIDE MODEST INSTABILITY...BUT HEIGHT RISES ALOFT SHOULD TEMPER STORM DEVELOPMENT. A ROGUE LATE AFTERNOON CELL OR TWO CANNOT BE RULED OUT ALONG WEAK SURFACE CONVERGENCE...BUT HAVE NOT MENTIONED IN THE FORECAST AT THIS TIME. HIGHS ON SUNDAY LOOK TO TOP OUT IN THE LOWER TO MID 90S...WITH A LAKE BREEZE PROVIDING SOME COOLING FOR DOWNTOWN CHICAGO AND NEARBY AREAS DURING THE AFTERNOON. THESE LAKE SHORE AREAS STILL MAY REACH 90 OR NEAR IT BEFORE THE LAKE BREEZE PUSHES THROUGH. MTF LONG TERM...SUNDAY NIGHT THROUGH SATURDAY... THE UPPER LEVEL RIDGE REESTABLISHES ITSELF ACROSS THE CENTRAL US AS THE TROUGH MOVES OFF TOWARD THE NEW ENGLAND AREA. A WEAKENING AREA OF LOW PRESSURE MOVES NORTH OF THE GREAT LAKES MONDAY NIGHT...WHILE ITS COLD FRONT SINKS SOUTH DOWN THE LAKE ON TUESDAY. PRECIP CHANCES DIMINISH AS THE TROUGH DRIFTS EASTWARD SUNDAY NIGHT. THE BEST CHANCE OF PRECIP IN THE EXTENDED IS ALONG THE COLD FRONT LATE TUESDAY THROUGH WEDNESDAY. GUIDANCE DIFFERS ON THE SPEED OF THE FRONT...WITH THE GFS BRINGING THE FRONT THROUGH MUCH FASTER THAN THE ECMWF. GIVEN ISSUES WITH THE GFS LATELY...AND THE ECMWF HAVING VERY CONSISTENT TIMING OVER THE PAST FEW DAYS...GOING WITH THE SLOWER SOLUTION. BOTH MODELS INDICATE MOISTURE WILL POOL ALONG THE FRONT...BUT THEN DISSIPATE AS THE FRONT ENTERS NORTHERN IL. THEREFORE...KEPT BEST PRECIP CHANCES NORTH OF I-80. LIMITED ACTUAL PRECIP CHANCES TO LESS THAN 50 PERCENT GIVEN THE MODEL TRENDS AND DRY CONDITIONS. HIGH PRESSURE BUILDS IN BEHIND THE FRONT...AND GUIDANCE SUGGESTS RANDOM PERIODS OF PRECIP DURING THE LATTER HALF OF NEXT WEEK. HOWEVER...WITH NO CLEAR SOURCE OF FORCING...QUESTIONABLE MOISTURE SOURCES...AND DROUGHT CONDITIONS...DECIDED TO KEEP THE REMAINDER OF THE EXTENDED DRY. AT THIS POINT THE BIGGER CRIME IS GETTING FOLKS HOPES UP FOR RAIN ONLY TO DISAPPOINT. HEAT BUILDS ACROSS THE REGION THROUGH TUESDAY. GUIDANCE SUGGESTS THERE WILL ONLY BE A SMALL PUSH OF SLIGHTLY COOLER AIR BEHIND THE FRONT...WITH WEDNESDAY LOOKING TO BE A BIT COOLER. HOWEVER 850 HPA TEMPS BEGIN TO WARM ALMOST IMMEDIATELY WITH THE UPPER LEVEL RIDGE SW OF THE CWA. THEREFORE...THE LATTER HALF OF NEXT WEEK LOOKS ABOVE AVERAGE. JEE && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 00Z... * LIGHT SOUTH-SOUTHEAST WIND BECOMING SOUTHWEST THIS EVENING. * VERY LOW PROBABILITY SHRA/TSRA POTENTIAL LATER TONIGHT INTO SUNDAY MORNING. * WIND SHIFT FROM LIGHT WEST-SOUTHWEST TO EAST-NORTHEAST WITH WEAK TROUGH PASSAGE MID-LATE SUNDAY MORNING AND LAKE BREEZE PUSH FROM THE EAST SUNDAY AFTERNOON. RATZER //DISCUSSION...UPDATED 00Z... A WEAK AREA OF LOW PRESSURE WAS OVER LAKE SUPERIOR EARLY THIS EVENING...WITH A TROUGH EXTENDING SOUTH-SOUTHWEST ACROSS WISCONSIN INTO WEST CENTRAL IOWA. ISOLATED THUNDERSTORMS WHICH HAD FORMED ACROSS THE CHICAGO AREA EARLIER HAVE DISSIPATED...WHILE A FEW ISOLATED STORMS REMAIN SOUTH OF THE TERMINALS ALONG AN APPROXIMATELY IKK-BMI-SPI LINE WHERE AN OUTFLOW BOUNDARY FROM OVERNIGHT CONVECTION HAD TAKEN RESIDENCE. ALL OF THIS ACTIVITY SHOULD CONTINUE TO FADE THIS EVENING WITH THE LOSS OF DIURNAL HEATING AND INSTABILITY. WINDS...WHICH HAD BECOME SOMEWHAT CHAOTIC WITH EARLIER LAKE BREEZE AND CONVECTIVE OUTFLOWS ACROSS METRO TERMINALS WERE RETURNING TO A SOUTH-SOUTHEAST DIRECTION AS OF 23Z AND SHOULD CONTINUE TO VEER SOUTHWEST THROUGH LATE EVENING. SPEEDS WILL REMAIN LESS THAN 10 KTS IN THE WEAK PRESSURE GRADIENT IN PLACE ACROSS THE REGION. FORECAST CONCERNS THEN SHIFT TO LOW PROBABILITY POTENTIAL FOR DEVELOPMENT OF ISOLATED TSRA AGAIN LATER TONIGHT INTO SUNDAY MORNING AS MID-LEVEL SHORT WAVE DIGS ACROSS THE UPPER MIDWEST AND WEAK SURFACE TROUGH OVER WI/IA GRADUALLY SAGS ACROSS THE AREA THROUGH SUNDAY. WEAK BUT PERSISTENT LIFT AND MOIST/WARM ADVECTION AHEAD OF THE MID LEVEL WAVE IS EXPECTED TO CONTINUE...WITH FORECAST SOUNDINGS INDICATING SOME MOISTENING AROUND THE 800 MB/6000 FT LEVEL DURING THE AFTER MIDNIGHT HOURS. WHILE MID/UPPER LEVEL TEMPS REMAIN RELATIVELY WARM...THIS DOES INDICATE THE POTENTIAL FOR DEVELOPMENT OF ISOLATED SHRA/TSRA DURING THE PRE-DAWN HOURS SIMILAR TO LAST NIGHT. MOST OF THE HIGH-RES EXPLICIT CONVECTION MODEL GUIDANCE DOES NOT DEVELOP SUCH CONVECTION... THOUGH THERE IS SOME SUPPORT IN THE SHORT-RANGE ENSEMBLE GUIDANCE. OVERALL HOWEVER...PROBABILITY AND CONFIDENCE IS TOO LOW TO INCLUDE IN POINT TAF PRODUCTS SO HAVE LIMITED FORECAST MENTION TO DEVELOPMENT OF A BROKEN VFR DECK AROUND 6000 FT. BETTER WARM/MOIST ADVECTION THEN SHIFTS NORTHEAST/EAST OF THE TERMINALS SUNDAY MORNING. SOME POTENTIAL EXISTS FOR ISOLATED TSRA/SHRA DEVELOPMENT THROUGH THE MORNING AS WEAK SURFACE TROUGH SAGS ACROSS AREA...THOUGH LIGHT WINDS AND RELATIVELY WARM MID-LEVEL TEMPS CONTINUE TO ARGUE AGAINST A SIGNIFICANT THREAT. WITH SURFACE BOUNDARY SAGGING ACROSS THE TERMINALS DURING THE MID- LATE MORNING HOURS...LIGHT SOUTHWEST-WEST WINDS ARE EXPECTED TO SHIFT NORTH. HOWEVER...GRADIENT IS VERY WEAK AND WINDS WILL LIKELY BECOME MORE VARIABLE. THIS WILL ALLOW EASTERLY LAKE BREEZE TO DEVELOP ACROSS CHICAGO SITES DURING THE EARLY-MID AFTERNOON HOURS. RATZER //ORD AND MDW CONFIDENCE...UPDATED 00Z... * HIGH CONFIDENCE IN OVERALL WIND TRENDS. * MEDIUM-HIGH CONFIDENCE IN NO ADDITIONAL TSRA AT TERMINALS. * HIGH CONFIDENCE IN LAKE BREEZE OCCURRENCE SUNDAY. RATZER //OUTLOOK FOR ORD/MDW FOR 12Z MONDAY-12Z SATURDAY...UPDATED 00Z... MONDAY...VFR. TUESDAY...VFR. CHANCE TSRA TUES NGT. WEDNESDAY...SLGT CHANCE TSRA. OTHERWISE VFR. THURSDAY AND FRIDAY...VFR. RATZER && .MARINE... 145 PM CDT LOW PRESSURE ACROSS LAKE SUPERIOR WILL CONTINUE TO MOVE EAST THROUGH SUNDAY. THIS WILL STEER A COOL FRONT ACROSS THE LAKE LATE TONIGHT. AHEAD OF THIS WILL BE SOME SCATTERED STORMS...SOME OF WHICH ARE LIKELY TO BE GUSTY BASED ON THE ENVIRONMENT. THESE WILL BE MOST FAVORED ACROSS THE SOUTHERN THIRD OF THE LAKE INCLUDING NEAR SHORE AREAS OF IL...IN...AND SOUTHWEST MI. WINDS BEHIND THE FRONT ON SUNDAY WILL BECOME LIGHT AND BEGIN TURNING BACK TO SOUTHERLY ALREADY BY AFTERNOON. SOUTHWEST WINDS WILL INCREASE ON MON...WITH OPEN WATER LOCATIONS ACROSS THE NORTH LIKELY REACHING 30 KT DURING MON NIGHT. A COOL FRONT WILL SLOWLY WORK SOUTH ACROSS THE LAKE ON TUESDAY AND TUESDAY NIGHT. THIS WILL SHIFT WINDS TO THE NORTH AND PROVIDE A FOCUS FOR SCATTERED THUNDERSTORMS ONCE AGAIN. MTF && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
832 PM CDT SAT JUL 14 2012 .DISCUSSION... ISSUED 825 PM CDT SAT JUL 14 2012 CONVECTION CONTINUES TO DISSIPATE EARLY THIS EVENING WITH SEVERAL LOCATIONS RECEIVING SOME DECENT RAINFALL FOR A CHANGE. PEORIA... BLOOMINGTON AND THE NWS AT LINCOLN RECEIVED OVER 1 INCH OF RAIN. SOME GUSTY WINDS AND SMALL HAIL WERE ASSOCIATED WITH THE STRONGEST UPDRAFTS...BUT THOSE WERE FEW AND FAR BETWEEN. LATEST SATELLITE DATA INDICATES THE 500 MB TROF AXIS RIGHT OVER THE FORECAST AREA EARLY THIS EVENING. THERE WAS ANOTHER WEAK SHORTWAVE SEEN OVER NW IL AND THAT WAS DRIFTING ESE AND MAY KEEP AT LEAST ISOLATED SHOWERS GOING INTO THE OVERNIGHT HOURS. AREAS THAT DID RECEIVE THE RAINFALL TODAY WILL SEE SOME FOG DEVELOP LATER TONIGHT. CURRENT ZONE FORECAST HAS A GOOD HANDLE ON THE TRENDS THIS EVENING SO OTHER THAN THE USUAL TWEAKS WITH THE HOURLY TEMPS...NO OTHER CHANGES WERE MADE. AS A RESULT...NO ZONE UPDATE WILL BE NEEDED EARLY THIS EVENING. SMITH && .AVIATION... ISSUED 620 PM CDT SAT JUL 14 2012 COVERAGE OF THUNDERSTORMS EARLY THIS EVENING AND THEN FOG POTENTIAL OVERNIGHT ARE THE MAIN FORECAST CONCERNS. WIDELY SCATTERED TSRA CONTINUES ALONG SEVERAL OUTFLOW BOUNDARIES LATE THIS AFTERNOON. THE MOST PERSISTENT AREA IS NEAR AND TO THE EAST OF KBMI. MOST OF THESE STORMS WERE MOVING SLOWLY EAST AT 10 MPH OR LESS PRODUCING LOCALLY BRIEF IFR CIGS/VSYBS WITH WIND GUSTS TO 40 MPH ALONG WITH TORRENTIAL RAINFALL. MOST OF THIS ACTIVITY IS EXPECTED TO DIMINISH AT OR JUST AFTER SUNSET. WE STILL MAY SEE ISOLATED SHOWERS AROUND FROM TIME TO TIME OVERNIGHT BUT COVERAGE TOO LIMITED TO INCLUDE IN THE 00Z TAFS. WITH MORE AREAS RECEIVING RAINFALL TODAY...FOG IS A DISTINCT POSSIBILITY...ESP AT PIA...BMI AND CMI WHERE WE WILL SEE SOME BRIEF MVFR VSBYS AT OR JUST AFTER 09Z. ONCE ANY FOG BURNS OFF...VFR CONDITIONS WILL PREVAIL DURING THE DAY SUNDAY. SFC WINDS WILL BE ALL OVER THE PLACE THIS EVENING THANKS TO THE NUMEROUS OUTFLOW BOUNDARIES SO WILL START OUT WITH A VARIABLE DIRECTION AND THEN MOST AREAS SHOULD SEE A LIGHT SOUTH WIND OVERNIGHT WITH SOUTH WINDS ON SUNDAY AT AROUND 10 KTS. SMITH && .PREV DISCUSSION... ISSUED 236 PM CDT SAT JUL 14 2012 SCATTERED SHOWERS ACROSS CENTRAL ILLINOIS CONTINUE...WITH VERY LITTLE MOVEMENT UNDER A WEAK UPPER LEVEL TROF. CONVECTIVE ACTIVITY TO THE NW THIS MORNING SHOWING UP AS A LITTLE WEAK VORTEX ON VIS SAT IMAGERY THIS AFTERNOON. BECAUSE OF THAT...HAVE MADE A COUPLE OF CHANGES TO THE POPS FOR THE OVERNIGHT. OTHER THAN THAT...FORECAST IS MOSTLY DRY BEYOND TONIGHT. NEXT CHANCE FOR PRECIP COMES MID WEEK NEXT WEEK. ECMWF NOW HAVING SIMILAR ISSUE TO THE LAST FEW RUNS OF THE GFS...SO KEEP SCALING BACK THE EXTENDED POPS SHORT TERM...TONIGHT AND TOMORROW... FIRST CONCERN IS THE SMALL VORTEX TO THE NW MOVING NEAR THE REGION IN THE OVERNIGHT. NEITHER HRRR NOR THE 4KM WRF ARE PICKING UP ON THE SYSTEM...BUT THE AVAILABLE MOISTURE HAS NOW BEEN A BIT ALTERED... PARTICULARLY IN THE EASTERN HALF OF THE CWA. FEEL LESS LIKE THE SHOWERS AFTER 00Z WILL BE LIMITED TO REMNANTS FROM TODAY...AND HAVE EXPANDED THE CHANCE POPS TO COVER THE ENTIRE OVERNIGHT. IN ANY SPOTS THAT CLEAR OUT IN THE OVERNIGHT...PARTICULARLY IN THE EAST WHERE THE BOUNDARY LAYER MOISTURE HAS BEEN SIGNIF INCREASED BY THE SHOWERS AND THUNDERSTORMS THIS AFTERNOON...PATCHY FOG WILL BE POSSIBLE IN THE EARLY MORNING...AND HAVE PLACED THE MENTION IN THE GRIDS FOR A COUPLE HOURS... MAINLY EAST OF I-55. TOMORROW...IN THE WAKE OF EXITING SHOWERS...SOME SMALL POPS MOSTLY SOUTH OF INTERSTATE 70. THESE POPS ARE MOSTLY A PRODUCT OF PREVIOUS MODEL SOLUTIONS WITH THE ACTIVITY IN THE OHIO RIVER VALLEY. WILL KEEP THEM IN FOR ANY LINGERING OVERNIGHT PRECIP...BUT MOSTLY REFLECTIVE OF EARLY IN THE DAY. LONG TERM...MONDAY THROUGH FRIDAY... SCATTERED PRECIP THIS AFTERNOON WILL DO LITTLE TO ALLEVIATE THE DROUGHT OVER THE REGION... PARTICULARLY WITH THE RIDGE BUILDING IN THE WESTERN CONUS YET AGAIN...AND PUSHING 850MB TEMPS UP AND SFC TEMPS BACK INTO THE MID-UPPER 90S. DRY WEATHER CONTINUES...HAVE RAISED MAX TEMPS A DEGREE OR TWO OVER GUIDANCE SINCE MODELS KEEP PRECIP AND CLOUD COVER IN ABSENCE OF REAL MOISTURE. BEST CHANCES FOR PRECIP IN EXTENDED COME WITH WED NIGHT AND A PASSING TROF/SFC BOUNDARY AS AN UPPER WAVE RIPPLES THROUGH THE 500MB FLOW ALONG THE US/CAN BORDER. THIS FAR SOUTH...AVAILABLE MOISTURE WILL BE QUESTIONABLE...AS WILL THE AMOUNT OF SFC CONVERGENCE. HAVE PULLED BACK THE BLENDED POPS WHEREVER POSSIBLE. SCT SHOWER ACTIVITY IS ALL THAT IS LIKELY IN THIS FORECAST...A VERY SMALL PERCENTAGE OF AREA WILL SEE THE PRECIP. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
724 PM CDT SAT JUL 14 2012 .DISCUSSION... 210 PM CDT CONCERNS WITH THE FORECAST ARE CENTERED ON CONVECTION THROUGH THIS EVENING...AND THEN HOT TEMPERATURES THE NEXT SEVERAL DAYS. SHORT TERM...REST OF THIS AFTERNOON THROUGH SUNDAY... TOWERING CUMULUS ALONG WITH SOME SCATTERED STORMS HAVE DEVELOPED EARLY THIS AFTERNOON ACROSS MAINLY THE EASTERN HALF OF THE FORECAST AREA ALONG AND AHEAD OF A SHEARED OUT UPPER IMPULSE AND AN ELEVATED /850-700MB/ WIND AND MOISTURE CONVERGENCE ZONE. GIVEN A FAIRLY UNSTABLE AIR MASS PER MODIFIED AMDAR SOUNDINGS AND RAP ANALYSIS...WITH MLCAPE VALUES OF 1000 TO 1500 J/KG...THESE STORMS SHOULD CONTINUE TO REGENERATE WITH THE FURTHER FOCI OF BOUNDARY INTERACTIONS. HAVE ALREADY SEEN THE DIVERGENT VELOCITY SIGNATURES ON RADAR UNDERNEATH THESE STORMS WITHIN JUST TWO RADAR VCPS...SHOWING THE DOWNDRAFT POTENTIAL ONCE AGAIN. ENVIRONMENTAL DCAPE VALUES ANALYZED BY THE RAP OF 700 TO 1000 J/KG ARE SLIGHTLY LESS THAN YESTERDAY...BUT SUFFICIENT ENOUGH FOR A POSSIBLE ISOLATED SEVERE GUST...INCLUDING IN NEARSHORE AREAS OF THE LAKE IN ANY STORMS THAT DRIFT NORTHEAST OVER THAT AREA. AN UPPER LEVEL SHORT WAVE...AS PART OF THE LARGER BROAD TROUGH...IS MOVING SOUTHEAST ACROSS WESTERN WI EARLY THIS AFTERNOON. THE INITIAL SURFACE BOUNDARY UNDERNEATH THIS IS HELPING TO FOCUS SOME SCATTERED STORMS...WITH SIMILAR ML INSTABILITY OF 1000 TO 1500 J/KG. MORE DEVELOPMENT IS ANTICIPATED THROUGH EARLY EVENING IN ADVANCE OF THIS AS CONVERGENCE IMPROVES...AND SOME OF THIS MAY POTENTIALLY BE ALONG OUTFLOW THAT IS ALREADY INTO NORTHWEST IL. EXPLICIT CONVECTIVE MODELS DO KEY IN ON SCATTERED STORM DEVELOPMENT TOWARD THE I-39 CORRIDOR BY LATE AFTERNOON. WITH THE SHORT WAVE AND FRONTAL APPROACH...ALONG WITH DEEP LAYER SHEAR VALUES OF SEMI-DECENT 30 KT PROJECTED...THESE SHOWERS AND STORMS HAVE POTENTIAL TO HANG ON LATER INTO THE EVENING. THE COOL FRONT WILL MOVE THROUGH THE AREA LATE TONIGHT AND SUNDAY MORNING...BUT WASHING OUT AS IT DOES. TEMPERATURES ON SUNDAY ARE ACTUALLY EXPECTED TO BE SLIGHTLY HIGHER THAN TODAY...AND DEW POINTS SHOULD BE CLOSE. THIS WILL AGAIN PROVIDE MODEST INSTABILITY...BUT HEIGHT RISES ALOFT SHOULD TEMPER STORM DEVELOPMENT. A ROGUE LATE AFTERNOON CELL OR TWO CANNOT BE RULED OUT ALONG WEAK SURFACE CONVERGENCE...BUT HAVE NOT MENTIONED IN THE FORECAST AT THIS TIME. HIGHS ON SUNDAY LOOK TO TOP OUT IN THE LOWER TO MID 90S...WITH A LAKE BREEZE PROVIDING SOME COOLING FOR DOWNTOWN CHICAGO AND NEARBY AREAS DURING THE AFTERNOON. THESE LAKE SHORE AREAS STILL MAY REACH 90 OR NEAR IT BEFORE THE LAKE BREEZE PUSHES THROUGH. MTF LONG TERM...SUNDAY NIGHT THROUGH SATURDAY... THE UPPER LEVEL RIDGE REESTABLISHES ITSELF ACROSS THE CENTRAL US AS THE TROUGH MOVES OFF TOWARD THE NEW ENGLAND AREA. A WEAKENING AREA OF LOW PRESSURE MOVES NORTH OF THE GREAT LAKES MONDAY NIGHT...WHILE ITS COLD FRONT SINKS SOUTH DOWN THE LAKE ON TUESDAY. PRECIP CHANCES DIMINISH AS THE TROUGH DRIFTS EASTWARD SUNDAY NIGHT. THE BEST CHANCE OF PRECIP IN THE EXTENDED IS ALONG THE COLD FRONT LATE TUESDAY THROUGH WEDNESDAY. GUIDANCE DIFFERS ON THE SPEED OF THE FRONT...WITH THE GFS BRINGING THE FRONT THROUGH MUCH FASTER THAN THE ECMWF. GIVEN ISSUES WITH THE GFS LATELY...AND THE ECMWF HAVING VERY CONSISTENT TIMING OVER THE PAST FEW DAYS...GOING WITH THE SLOWER SOLUTION. BOTH MODELS INDICATE MOISTURE WILL POOL ALONG THE FRONT...BUT THEN DISSIPATE AS THE FRONT ENTERS NORTHERN IL. THEREFORE...KEPT BEST PRECIP CHANCES NORTH OF I-80. LIMITED ACTUAL PRECIP CHANCES TO LESS THAN 50 PERCENT GIVEN THE MODEL TRENDS AND DRY CONDITIONS. HIGH PRESSURE BUILDS IN BEHIND THE FRONT...AND GUIDANCE SUGGESTS RANDOM PERIODS OF PRECIP DURING THE LATTER HALF OF NEXT WEEK. HOWEVER...WITH NO CLEAR SOURCE OF FORCING...QUESTIONABLE MOISTURE SOURCES...AND DROUGHT CONDITIONS...DECIDED TO KEEP THE REMAINDER OF THE EXTENDED DRY. AT THIS POINT THE BIGGER CRIME IS GETTING FOLKS HOPES UP FOR RAIN ONLY TO DISAPPOINT. HEAT BUILDS ACROSS THE REGION THROUGH TUESDAY. GUIDANCE SUGGESTS THERE WILL ONLY BE A SMALL PUSH OF SLIGHTLY COOLER AIR BEHIND THE FRONT...WITH WEDNESDAY LOOKING TO BE A BIT COOLER. HOWEVER 850 HPA TEMPS BEGIN TO WARM ALMOST IMMEDIATELY WITH THE UPPER LEVEL RIDGE SW OF THE CWA. THEREFORE...THE LATTER HALF OF NEXT WEEK LOOKS ABOVE AVERAGE. JEE && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 00Z... * LIGHT SOUTH-SOUTHEAST WIND BECOMING SOUTHWEST THIS EVENING. * VERY LOW PROBABILITY SHRA/TSRA POTENTIAL LATER TONIGHT INTO SUNDAY MORNING. * WIND SHIFT FROM LIGHT WEST-SOUTHWEST TO EAST-NORTHEAST WITH WEAK TROUGH PASSAGE MID-LATE SUNDAY MORNING AND LAKE BREEZE PUSH FROM THE EAST SUNDAY AFTERNOON. RATZER //DISCUSSION...UPDATED 00Z... A WEAK AREA OF LOW PRESSURE WAS OVER LAKE SUPERIOR EARLY THIS EVENING...WITH A TROUGH EXTENDING SOUTH-SOUTHWEST ACROSS WISCONSIN INTO WEST CENTRAL IOWA. ISOLATED THUNDERSTORMS WHICH HAD FORMED ACROSS THE CHICAGO AREA EARLIER HAVE DISSIPATED...WHILE A FEW ISOLATED STORMS REMAIN SOUTH OF THE TERMINALS ALONG AN APPROXIMATELY IKK-BMI-SPI LINE WHERE AN OUTFLOW BOUNDARY FROM OVERNIGHT CONVECTION HAD TAKEN RESIDENCE. ALL OF THIS ACTIVITY SHOULD CONTINUE TO FADE THIS EVENING WITH THE LOSS OF DIURNAL HEATING AND INSTABILITY. WINDS...WHICH HAD BECOME SOMEWHAT CHAOTIC WITH EARLIER LAKE BREEZE AND CONVECTIVE OUTFLOWS ACROSS METRO TERMINALS WERE RETURNING TO A SOUTH-SOUTHEAST DIRECTION AS OF 23Z AND SHOULD CONTINUE TO VEER SOUTHWEST THROUGH LATE EVENING. SPEEDS WILL REMAIN LESS THAN 10 KTS IN THE WEAK PRESSURE GRADIENT IN PLACE ACROSS THE REGION. FORECAST CONCERNS THEN SHIFT TO LOW PROBABILITY POTENTIAL FOR DEVELOPMENT OF ISOLATED TSRA AGAIN LATER TONIGHT INTO SUNDAY MORNING AS MID-LEVEL SHORT WAVE DIGS ACROSS THE UPPER MIDWEST AND WEAK SURFACE TROUGH OVER WI/IA GRADUALLY SAGS ACROSS THE AREA THROUGH SUNDAY. WEAK BUT PERSISTENT LIFT AND MOIST/WARM ADVECTION AHEAD OF THE MID LEVEL WAVE IS EXPECTED TO CONTINUE...WITH FORECAST SOUNDINGS INDICATING SOME MOISTENING AROUND THE 800 MB/6000 FT LEVEL DURING THE AFTER MIDNIGHT HOURS. WHILE MID/UPPER LEVEL TEMPS REMAIN RELATIVELY WARM...THIS DOES INDICATE THE POTENTIAL FOR DEVELOPMENT OF ISOLATED SHRA/TSRA DURING THE PRE-DAWN HOURS SIMILAR TO LAST NIGHT. MOST OF THE HIGH-RES EXPLICIT CONVECTION MODEL GUIDANCE DOES NOT DEVELOP SUCH CONVECTION... THOUGH THERE IS SOME SUPPORT IN THE SHORT-RANGE ENSEMBLE GUIDANCE. OVERALL HOWEVER...PROBABILITY AND CONFIDENCE IS TOO LOW TO INCLUDE IN POINT TAF PRODUCTS SO HAVE LIMITED FORECAST MENTION TO DEVELOPMENT OF A BROKEN VFR DECK AROUND 6000 FT. BETTER WARM/MOIST ADVECTION THEN SHIFTS NORTHEAST/EAST OF THE TERMINALS SUNDAY MORNING. SOME POTENTIAL EXISTS FOR ISOLATED TSRA/SHRA DEVELOPMENT THROUGH THE MORNING AS WEAK SURFACE TROUGH SAGS ACROSS AREA...THOUGH LIGHT WINDS AND RELATIVELY WARM MID-LEVEL TEMPS CONTINUE TO ARGUE AGAINST A SIGNIFICANT THREAT. WITH SURFACE BOUNDARY SAGGING ACROSS THE TERMINALS DURING THE MID- LATE MORNING HOURS...LIGHT SOUTHWEST-WEST WINDS ARE EXPECTED TO SHIFT NORTH. HOWEVER...GRADIENT IS VERY WEAK AND WINDS WILL LIKELY BECOME MORE VARIABLE. THIS WILL ALLOW EASTERLY LAKE BREEZE TO DEVELOP ACROSS CHICAGO SITES DURING THE EARLY-MID AFTERNOON HOURS. RATZER //ORD AND MDW CONFIDENCE...UPDATED 00Z... * HIGH CONFIDENCE IN OVERALL WIND TRENDS. * MEDIUM-HIGH CONFIDENCE IN NO ADDITIONAL TSRA AT TERMINALS. * HIGH CONFIDENCE IN LAKE BREEZE OCCURRENCE SUNDAY. RATZER //OUTLOOK FOR ORD/MDW FOR 12Z MONDAY-12Z SATURDAY...UPDATED 00Z... MONDAY...VFR. TUESDAY...VFR. CHANCE TSRA TUES NGT. WEDNESDAY...SLGT CHANCE TSRA. OTHERWISE VFR. THURSDAY AND FRIDAY...VFR. RATZER && .MARINE... 145 PM CDT LOW PRESSURE ACROSS LAKE SUPERIOR WILL CONTINUE TO MOVE EAST THROUGH SUNDAY. THIS WILL STEER A COOL FRONT ACROSS THE LAKE LATE TONIGHT. AHEAD OF THIS WILL BE SOME SCATTERED STORMS...SOME OF WHICH ARE LIKELY TO BE GUSTY BASED ON THE ENVIRONMENT. THESE WILL BE MOST FAVORED ACROSS THE SOUTHERN THIRD OF THE LAKE INCLUDING NEAR SHORE AREAS OF IL...IN...AND SOUTHWEST MI. WINDS BEHIND THE FRONT ON SUNDAY WILL BECOME LIGHT AND BEGIN TURNING BACK TO SOUTHERLY ALREADY BY AFTERNOON. SOUTHWEST WINDS WILL INCREASE ON MON...WITH OPEN WATER LOCATIONS ACROSS THE NORTH LIKELY REACHING 30 KT DURING MON NIGHT. A COOL FRONT WILL SLOWLY WORK SOUTH ACROSS THE LAKE ON TUESDAY AND TUESDAY NIGHT. THIS WILL SHIFT WINDS TO THE NORTH AND PROVIDE A FOCUS FOR SCATTERED THUNDERSTORMS ONCE AGAIN. MTF && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
625 PM CDT SAT JUL 14 2012 .DISCUSSION... ISSUED 236 PM CDT SAT JUL 14 2012 SCATTERED SHOWERS ACROSS CENTRAL ILLINOIS CONTINUE...WITH VERY LITTLE MOVEMENT UNDER A WEAK UPPER LEVEL TROF. CONVECTIVE ACTIVITY TO THE NW THIS MORNING SHOWING UP AS A LITTLE WEAK VORTEX ON VIS SAT IMAGERY THIS AFTERNOON. BECAUSE OF THAT...HAVE MADE A COUPLE OF CHANGES TO THE POPS FOR THE OVERNIGHT. OTHER THAN THAT...FORECAST IS MOSTLY DRY BEYOND TONIGHT. NEXT CHANCE FOR PRECIP COMES MID WEEK NEXT WEEK. ECMWF NOW HAVING SIMILAR ISSUE TO THE LAST FEW RUNS OF THE GFS...SO KEEP SCALING BACK THE EXTENDED POPS SHORT TERM...TONIGHT AND TOMORROW... FIRST CONCERN IS THE SMALL VORTEX TO THE NW MOVING NEAR THE REGION IN THE OVERNIGHT. NEITHER HRRR NOR THE 4KM WRF ARE PICKING UP ON THE SYSTEM...BUT THE AVAILABLE MOISTURE HAS NOW BEEN A BIT ALTERED... PARTICULARLY IN THE EASTERN HALF OF THE CWA. FEEL LESS LIKE THE SHOWERS AFTER 00Z WILL BE LIMITED TO REMNANTS FROM TODAY...AND HAVE EXPANDED THE CHANCE POPS TO COVER THE ENTIRE OVERNIGHT. IN ANY SPOTS THAT CLEAR OUT IN THE OVERNIGHT...PARTICULARLY IN THE EAST WHERE THE BOUNDARY LAYER MOISTURE HAS BEEN SIGNIF INCREASED BY THE SHOWERS AND THUNDERSTORMS THIS AFTERNOON...PATCHY FOG WILL BE POSSIBLE IN THE EARLY MORNING...AND HAVE PLACED THE MENTION IN THE GRIDS FOR A COUPLE HOURS... MAINLY EAST OF I-55. TOMORROW...IN THE WAKE OF EXITING SHOWERS...SOME SMALL POPS MOSTLY SOUTH OF INTERSTATE 70. THESE POPS ARE MOSTLY A PRODUCT OF PREVIOUS MODEL SOLUTIONS WITH THE ACTIVITY IN THE OHIO RIVER VALLEY. WILL KEEP THEM IN FOR ANY LINGERING OVERNIGHT PRECIP...BUT MOSTLY REFLECTIVE OF EARLY IN THE DAY. LONG TERM...MONDAY THROUGH FRIDAY... SCATTERED PRECIP THIS AFTERNOON WILL DO LITTLE TO ALLEVIATE THE DROUGHT OVER THE REGION... PARTICULARLY WITH THE RIDGE BUILDING IN THE WESTERN CONUS YET AGAIN...AND PUSHING 850MB TEMPS UP AND SFC TEMPS BACK INTO THE MID-UPPER 90S. DRY WEATHER CONTINUES...HAVE RAISED MAX TEMPS A DEGREE OR TWO OVER GUIDANCE SINCE MODELS KEEP PRECIP AND CLOUD COVER IN ABSENCE OF REAL MOISTURE. BEST CHANCES FOR PRECIP IN EXTENDED COME WITH WED NIGHT AND A PASSING TROF/SFC BOUNDARY AS AN UPPER WAVE RIPPLES THROUGH THE 500MB FLOW ALONG THE US/CAN BORDER. THIS FAR SOUTH...AVAILABLE MOISTURE WILL BE QUESTIONABLE...AS WILL THE AMOUNT OF SFC CONVERGENCE. HAVE PULLED BACK THE BLENDED POPS WHEREVER POSSIBLE. SCT SHOWER ACTIVITY IS ALL THAT IS LIKELY IN THIS FORECAST...A VERY SMALL PERCENTAGE OF AREA WILL SEE THE PRECIP. && .AVIATION... ISSUED 620 PM CDT SAT JUL 14 2012 COVERAGE OF THUNDERSTORMS EARLY THIS EVENING AND THEN FOG POTENTIAL OVERNIGHT ARE THE MAIN FORECAST CONCERNS. WIDELY SCATTERED TSRA CONTINUES ALONG SEVERAL OUTFLOW BOUNDARIES LATE THIS AFTERNOON. THE MOST PERSISTENT AREA IS NEAR AND TO THE EAST OF KBMI. MOST OF THESE STORMS WERE MOVING SLOWLY EAST AT 10 MPH OR LESS PRODUCING LOCALLY BRIEF IFR CIGS/VSYBS WITH WIND GUSTS TO 40 MPH ALONG WITH TORRENTIAL RAINFALL. MOST OF THIS ACTIVITY IS EXPECTED TO DIMINISH AT OR JUST AFTER SUNSET. WE STILL MAY SEE ISOLATED SHOWERS AROUND FROM TIME TO TIME OVERNIGHT BUT COVERAGE TOO LIMITED TO INCLUDE IN THE 00Z TAFS. WITH MORE AREAS RECEIVING RAINFALL TODAY...FOG IS A DISTINCT POSSIBILITY...ESP AT PIA...BMI AND CMI WHERE WE WILL SEE SOME BRIEF MVFR VSBYS AT OR JUST AFTER 09Z. ONCE ANY FOG BURNS OFF...VFR CONDITIONS WILL PREVAIL DURING THE DAY SUNDAY. SFC WINDS WILL BE ALL OVER THE PLACE THIS EVENING THANKS TO THE NUMEROUS OUTFLOW BOUNDARIES SO WILL START OUT WITH A VARIABLE DIRECTION AND THEN MOST AREAS SHOULD SEE A LIGHT SOUTH WIND OVERNIGHT WITH SOUTH WINDS ON SUNDAY AT AROUND 10 KTS. SMITH && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
653 AM CDT FRI JUL 13 2012 .UPDATE... RAP TRENDS AND THE LIFT TOOL CONTINUE TO GENERALLY SUPPORT EARLIER THINKING. CONVECTION SHOULD CONTINUE THROUGH MID MORNING BEFORE SLOWLY DISSIPATING EITHER LATE THIS MORNING OR BY EARLY AFTERNOON. BASED ON RADAR TRENDS...WILL ADJUST POPS FOR THE MORNING HOURS WITH HIGHER COVERAGE IN THE NORTHWEST/NORTH PARTS OF THE CWFA. IF THE CURRENT RAP TRENDS ARE CORRECT DIURNAL CONVECTION SHOULD DEVELOP BY MID AFTERNOON AS THE VORT MAX/SHORTWAVE BEHIND THE CURRENT ONE BEGINS MOVING INTO EASTERN IOWA. WEAK WIND FLOW/SHEAR ALOFT SHOULD RESULT IN NON-SEVERE STORMS. OVERALL COVERAGE THIS AFTERNOON WILL AGAIN BE ISOLATED TO SCATTERED. ..08.. && .AVIATION... NOCTURNAL ELEVATED CONVECTION CONTINUES TO BE HELPED BY A DISTURBANCE ALOFT. POTENTIAL MVFR CONDITIONS WITH TSRA MAY BE SEEN AT KCID/KDBQ/KMLI 12Z-18Z/13. DIURNAL TSRA CONVECTION IS EXPECTED TO DVLP AFT 18Z/13 AND DISSIPATE AFTER SUNSET. OTHERWISE...VFR CONDITIONS ARE EXPECTED OUTSIDE OF TSRA THROUGH 03Z/14. THERE IS A POSSIBILITY OF NOCTURNAL TSRA AFT 06Z/14. ..08.. && .PREV DISCUSSION... /ISSUED 356 AM CDT FRI JUL 13 2012/ SYNOPSIS... 06Z SFC ANALYSIS HAS HIGH PRESSURE OVER THE EASTERN GREAT LAKES WITH TWO TROFS ACROSS THE PLAINS. DEW POINTS WERE IN THE 50S ACROSS THE IMMEDIATE GREAT LAKES WITH 60S OVER MOST OF THE MIDWEST. SHORT TERM...TODAY AND TONIGHT... SATELLITE TRENDS THE PAST SEVERAL HOURS HAS HAD CONSIDERABLE DEVELOPMENT OF MID LEVEL CLOUDS. RADAR IN TURN HAS ALSO DEVELOPED ELEVATED ISOLATED TO SCATTERED CONVECTION ACROSS IOWA. RAP TRENDS AND THE LIFT TOOL HAVE BEEN QUITE USEFUL IN DEPICTING THE CURRENT CONVECTION. THE LIFT TOOL SHOWS WEAK THETA E GRADIENTS WORKING IN CONCERT WITH CONVERGENCE TO PRODUCE THE CONVECTION. RAP TRENDS PERSIST THIS ACROSS ROUGHLY THE NORTHWEST TWO THIRDS OF THE CWFA DURING THE MORNING HOURS IN ASSOCIATION WITH THE VORT MAX MOVING THROUGH IN THE FLOW ALOFT. INTERESTINGLY...THE VORT MAX SUDDENLY STRENGTHENS BY LATE MORNING WHICH MAY OR MAY NOT BE A CONVECTIVE FEEDBACK ISSUE WITH THE RAP MODEL. THE QUESTION THEN TURNS TO WHETHER OR NOT CONVECTION WILL DEVELOP DURING THE AFTERNOON HOURS. THE LIFT TOOL HAS NEGATIVE THETA E LAPSE RATES ACROSS THE AREA WITH SOME WEAK CONVERGENCE ALOFT. THE MAIN VARIABLE WILL BE HOW MUCH THE CLOUDS HOLD DOWN TEMPERATURES. CONVECTIVE TEMPERATURES ARE ESSENTIALLY IN THE UPPER 80S TO LOWER 90S WHICH IS THE FCST MAX TEMPERATURES. THUS WILL CONTINUE WITH ISOLATED TO SCATTERED CONVECTION DURING THE AFTERNOON. ANY DIURNAL CONVECTION THAT DEVELOPS THIS AFTERNOON WILL CONTINUE INTO THE EARLY EVENING AND SHOULD DISSIPATE SHORTLY AFTER SUNSET. HOWEVER...ANOTHER VORT MAX IN THE FLOW IS JUST UPSTREAM SO CONVECTION COULD PERSIST LATER INTO THE EVENING...OR...RE-DEVELOP AROUND MIDNIGHT AND THEN PERSIST THROUGH THE NIGHT. GIVEN THE WEAK CHARACTERISTICS OF THE FLOW ALOFT...THE SECOND SCENARIO WOULD SEEM MORE PLAUSIBLE. INDEED THE LIFT TOOL DOES SUGGEST ANOTHER THETA E GRADIENT MOVING INTO THE CWFA AROUND MIDNIGHT. THUS...WILL GO WITH THE CONCEPT OF ISOLATED TO SCATTERED NOCTURNAL CONVECTION DEVELOPING AND THEN PERSISTING THROUGH SUNRISE. ..08.. LONG TERM...SATURDAY THROUGH THURSDAY... THE LATEST MODEL RUNS CONTINUE TO DROP A WEAK BOUNDARY INTO THE REGION SATURDAY. THIS SHOULD GIVE AT LEAST THE NORTHERN HALF OF THE AREA A REASONABLE CHANCE OF SCATTERED THUNDERSTORMS ESPECIALLY WITH THE BOUNDARY SETTLING INTO THE NORTH DURING PRIME HEATING. WILL GO WITH 30/40 POPS FOR THE NORTHERN HALF OF THE CWFA AND KEEP LOW CHANCE POPS GOING IN THE FAR SOUTH WHERE THUNDERSTORM DEVELOPMENT WILL BE DEPENDENT ON OUTFLOWS TO PROVIDE SOME FOCUS FOR TSRA INITIATION. ANY STORMS THAT DEVELOP SATURDAY SHOULD BE OF THE PULSE VARIETY WITH THE WEAK DEEP LAYER SHEAR IN PLACE. THE NAM WAS SHOWING CAPES EXCEEDING 3000 J/KG DURING THE AFTERNOON. IF THESE CAPES ARE REALIZED THEN SOME OF THE STRONGER STORMS WILL BE CAPABLE OF PRODUCING SOME STRONG WINDS GUSTS. KEPT SOME LOW POPS GOING FOR SATURDAY NIGHT WITH THE BOUNDARY STILL IN THE AREA AND CONTINUED SOME LOW POPS SOUTHEAST SUNDAY TO ACCOUNT FOR THE ECMWF SOLUTION WHICH HOLDS A WEAK BOUNDARY IN OUR SOUTHEAST DURING THE DAY. SUNDAY NIGHT AND MONDAY WARMER AIR POURS BACK TO INTO THE REGION AS UPPER RIDGING BUILDS EAST OUT OF THE ROCKIES. IT LOOKS LIKE WIDESPREAD 90S WILL RETURN TO THE REGION MONDAY AND TUESDAY WITH HEAT INDICES APPROACHING 100. WITH THE RIDGE BUILDING IN...A DRY FORECAST IS IN ORDER MONDAY AND MONDAY NIGHT. FOR TUESDAY THROUGH THURSDAY THE GFS/ECMWF CONTINUE TO SHOW A S/W MOVING THROUGH THE NORTHERN TIER OF STATES AND SUPPRESSING THE MIDWEST RIDGE. THE S/W WILL ALSO DROP ANOTHER BOUNDARY SOUTH INTO THE REGION. WITH THE GFS/ECMWF HOLDING THE BOUNDARY JUST SOUTH OF THE AREA INTO THURSDAY WILL KEEP SOME LOW POPS GOING TUESDAY THROUGH THURSDAY...BUT HOLD THEM IN THE SLIGHT CHANCE/LOW CHANCE RANGE SINCE MODELS KEEP MID LEVEL TEMPS ON THE WARM SIDE NEAR THE BOUNDARY. IF THE GFS/ECMWF PROGS VERIFY THEN A SURFACE HIGH SETTING UP OVER THE WESTERN GREAT LAKES SHOULD KEEP EAST/NORTHEAST LOW LEVEL FLOW OVER THE AREA FOR MID/LATE WEEK. TEMPERATURES TUESDAY SHOULD STILL BE IN THE 90S AS THE FRONT MOVES THROUGH THEN INCREASING EAST OR NORTHEAST FLOW WEDNESDAY INTO THURSDAY SHOULD TAKE THE EDGE OFF THE HEAT. DLF && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$
AREA FORECAST DISCUSSION...CORRECTED
NWS QUAD CITIES IA IL
356 AM CDT FRI JUL 13 2012 .SYNOPSIS... 06Z SFC ANALYSIS HAS HIGH PRESSURE OVER THE EASTERN GREAT LAKES WITH TWO TROFS ACROSS THE PLAINS. DEW POINTS WERE IN THE 50S ACROSS THE IMMEDIATE GREAT LAKES WITH 60S OVER MOST OF THE MIDWEST. && .SHORT TERM...TODAY AND TONIGHT... SATELLITE TRENDS THE PAST SEVERAL HOURS HAS HAD CONSIDERABLE DEVELOPMENT OF MID LEVEL CLOUDS. RADAR IN TURN HAS ALSO DEVELOPED ELEVATED ISOLATED TO SCATTERED CONVECTION ACROSS IOWA. RAP TRENDS AND THE LIFT TOOL HAVE BEEN QUITE USEFUL IN DEPICTING THE CURRENT CONVECTION. THE LIFT TOOL SHOWS WEAK THETA E GRADIENTS WORKING IN CONCERT WITH CONVERGENCE TO PRODUCE THE CONVECTION. RUC TRENDS PERSIST THIS ACROSS ROUGHLY THE NORTHWEST TWO THIRDS OF THE CWFA DURING THE MORNING HOURS IN ASSOCIATION WITH THE VORT MAX MOVING THROUGH IN THE FLOW ALOFT. INTERESTINGLY...THE VORT MAX SUDDENLY STRENGTHENS BY LATE MORNING WHICH MAY OR MAY NOT BE A CONVECTIVE FEEDBACK ISSUE WITH THE RAP MODEL. THE QUESTION THEN TURNS TO WHETHER OR NOT CONVECTION WILL DEVELOP DURING THE AFTERNOON HOURS. THE LIFT TOOL HAS NEGATIVE THETA E LAPSE RATES ACROSS THE AREA WITH SOME WEAK CONVERGENCE ALOFT. THE MAIN VARIABLE WILL BE HOW MUCH THE CLOUDS HOLD DOWN TEMPERATURES. CONVECTIVE TEMPERATURES ARE ESSENTIALLY IN THE UPPER 80S TO LOWER 90S WHICH IS THE FCST MAX TEMPERATURES. THUS WILL CONTINUE WITH ISOLATED TO SCATTERED CONVECTION DURING THE AFTERNOON. ANY DIURNAL CONVECTION THAT DEVELOPS THIS AFTERNOON WILL CONTINUE INTO THE EARLY EVENING AND SHOULD DISSIPATE SHORTLY AFTER SUNSET. HOWEVER...ANOTHER VORT MAX IN THE FLOW IS JUST UPSTREAM SO CONVECTION COULD PERSIST LATER INTO THE EVENING...OR...RE-DEVELOP AROUND MIDNIGHT AND THEN PERSIST THROUGH THE NIGHT. GIVEN THE WEAK CHARACTERISTICS OF THE FLOW ALOFT...THE SECOND SCENARIO WOULD SEEM MORE PLAUSIBLE. INDEED THE LIFT TOOL DOES SUGGEST ANOTHER THETA E GRADIENT MOVING INTO THE CWFA AROUND MIDNIGHT. THUS...WILL GO WITH THE CONCEPT OF ISOLATED TO SCATTERED NOCTURNAL CONVECTION DEVELOPING AND THEN PERSISTING THROUGH SUNRISE. 08 .LONG TERM...SATURDAY THROUGH THURSDAY... THE LATEST MODEL RUNS CONTINUE TO DROP A WEAK BOUNDARY INTO THE REGION SATURDAY. THIS SHOULD GIVE AT LEAST THE NORTHERN HALF OF THE AREA A REASONABLE CHANCE OF SCATTERED THUNDERSTORMS ESPECIALLY WITH THE BOUNDARY SETTLING INTO THE NORTH DURING PRIME HEATING. WILL GO WITH 30/40 POPS FOR THE NORTHERN HALF OF THE CWFA AND KEEP LOW CHANCE POPS GOING IN THE FAR SOUTH WHERE THUNDERSTORM DEVELOPMENT WILL BE DEPENDENT ON OUTFLOWS TO PROVIDE SOME FOCUS FOR TSRA INITIATION. ANY STORMS THAT DEVELOP SATURDAY SHOULD BE OF THE PULSE VARIETY WITH THE WEAK DEEP LAYER SHEAR IN PLACE. THE NAM WAS SHOWING CAPES EXCEEDING 3000 J/KG DURING THE AFTERNOON. IF THESE CAPES ARE REALIZED THEN SOME OF THE STRONGER STORMS WILL BE CAPABLE OF PRODUCING SOME STRONG WINDS GUSTS. KEPT SOME LOW POPS GOING FOR SATURDAY NIGHT WITH THE BOUNDARY STILL IN THE AREA AND CONTINUED SOME LOW POPS SOUTHEAST SUNDAY TO ACCOUNT FOR THE ECMWF SOLUTION WHICH HOLDS A WEAK BOUNDARY IN OUR SOUTHEAST DURING THE DAY. SUNDAY NIGHT AND MONDAY WARMER AIR POURS BACK TO INTO THE REGION AS UPPER RIDGING BUILDS EAST OUT OF THE ROCKIES. IT LOOKS LIKE WIDESPREAD 90S WILL RETURN TO THE REGION MONDAY AND TUESDAY WITH HEAT INDICES APPROACHING 100. WITH THE RIDGE BUILDING IN...A DRY FORECAST IS IN ORDER MONDAY AND MONDAY NIGHT. FOR TUESDAY THROUGH THURSDAY THE GFS/ECMWF CONTINUE TO SHOW A S/W MOVING THROUGH THE NORTHERN TIER OF STATES AND SUPPRESSING THE MIDWEST RIDGE. THE S/W WILL ALSO DROP ANOTHER BOUNDARY SOUTH INTO THE REGION. WITH THE GFS/ECMWF HOLDING THE BOUNDARY JUST SOUTH OF THE AREA INTO THURSDAY WILL KEEP SOME LOW POPS GOING TUESDAY THROUGH THURSDAY...BUT HOLD THEM IN THE SLIGHT CHANCE/LOW CHANCE RANGE SINCE MODELS KEEP MID LEVEL TEMPS ON THE WARM SIDE NEAR THE BOUNDARY. IF THE GFS/ECMWF PROGS VERIFY THEN A SURFACE HIGH SETTING UP OVER THE WESTERN GREAT LAKES SHOULD KEEP EAST/NORTHEAST LOW LEVEL FLOW OVER THE AREA FOR MID/LATE WEEK. TEMPERATURES TUESDAY SHOULD STILL BE IN THE 90S AS THE FRONT MOVES THROUGH THEN INCREASING EAST OR NORTHEAST FLOW WEDNESDAY INTO THURSDAY SHOULD TAKE THE EDGE OFF THE HEAT. DLF && .AVIATION... ELEVATED CONVECTION HAS DEVELOPED IN RESPONSE TO AN UPPER LEVEL DISTURBANCE. KCID IS BEING AFFECTED WITH KDBQ/KMLI POSSIBLY BEING AFFECTED AS WELL. MVFR CONDITIONS THAT MAY BRIEFLY DROP TO IFR ARE EXPECTED. ISOLATED TO SCATTERED CONVECTION IS EXPECTED TO PERSIST THROUGH 00Z/14 AND POSSIBLY BEYOND. WHEN TSRA OR VCTS IS NOT AFFECTING A TAF SITE...VFR CONDITIONS ARE EXPECTED. 08 && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$
AREA FORECAST DISCUSSION...CORRECTED
NWS QUAD CITIES IA IL
342 AM CDT FRI JUL 13 2012 .SYNOPSIS... 06Z SFC ANALYSIS HAS HIGH PRESSURE OVER THE EASTERN GREAT LAKES WITH TWO TROFS ACROSS THE PLAINS. DEW POINTS WERE IN THE 50S ACROSS THE IMMEDIATE GREAT LAKES WITH 60S OVER MOST OF THE MIDWEST. && .SHORT TERM...ODAY AND TONIGHT... SATELLITE TRENDS THE PAST SEVERAL HOURS HAS HAD CONSIDERABLE DEVELOPMENT OF MID LEVEL CLOUDS. RADAR IN TURN HAS ALSO DEVELOPED ELEVATED ISOLATED TO SCATTERED CONVECTION ACROSS IOWA. RAP TRENDS AND THE LIFT TOOL HAVE BEEN QUITE USEFUL IN DEPICTING THE CURRENT CONVECTION. THE LIFT TOOL SHOWS WEAK THETA E GRADIENTS WORKING IN CONCERT WITH CONVERGENCE TO PRODUCE THE CONVECTION. RUC TRENDS PERSIST THIS ACROSS ROUGHLY THE NORTHWEST TWO THIRDS OF THE CWFA DURING THE MORNING HOURS IN ASSOCIATION WITH THE VORT MAX MOVING THROUGH IN THE FLOW ALOFT. INTERESTINGLY...THE VORT MAX SUDDENLY STRENGTHENS BY LATE MORNING WHICH MAY OR MAY NOT BE A CONVECTIVE FEEDBACK ISSUE WITH THE RAP MODEL. THE QUESTION THEN TURNS TO WHETHER OR NOT CONVECTION WILL DEVELOP DURING THE AFTERNOON HOURS. THE LIFT TOOL HAS NEGATIVE THETA E LAPSE RATES ACROSS THE AREA WITH SOME WEAK CONVERGENCE ALOFT. THE MAIN VARIABLE WILL BE HOW MUCH THE CLOUDS HOLD DOWN TEMPERATURES. CONVECTIVE TEMPERATURES ARE ESSENTIALLY IN THE UPPER 80S TO LOWER 90S WHICH IS THE FCST MAX TEMPERATURES. THUS WILL CONTINUE WITH ISOLATED TO SCATTERED CONVECTION DURING THE AFTERNOON. ANY DIURNAL CONVECTION THAT DEVELOPS THIS AFTERNOON WILL CONTINUE INTO THE EARLY EVENING AND SHOULD DISSIPATE SHORTLY AFTER SUNSET. HOWEVER...ANOTHER VORT MAX IN THE FLOW IS JUST UPSTREAM SO CONVECTION COULD PERSIST LATER INTO THE EVENING...OR...RE-DEVELOP AROUND MIDNIGHT AND THEN PERSIST THROUGH THE NIGHT. GIVEN THE WEAK CHARACTERISTICS OF THE FLOW ALOFT...THE SECOND SCENARIO WOULD SEEM MORE PLAUSIBLE. INDEED THE LIFT TOOL DOES SUGGEST ANOTHER THETA E GRADIENT MOVING INTO THE CWFA AROUND MIDNIGHT. THUS...WILL GO WITH THE CONCEPT OF ISOLATED TO SCATTERED NOCTURNAL CONVECTION DEVELOPING AND THEN PERSISTING THROUGH SUNRISE. 08 .LONG TERM...SATURDAY THROUGH THURSDAY... THE LATEST MODEL RUNS CONTINUE TO DROP A WEAK BOUNDARY INTO THE REGION SATURDAY. THIS SHOULD GIVE AT LEAST THE NORTHERN HALF OF THE AREA A REASONABLE CHANCE OF SCATTERED THUNDERSTORMS ESPECIALLY WITH THE BOUNDARY SETTLING INTO THE NORTH DURING PRIME HEATING. WILL GO WITH 30/40 POPS FOR THE NORTHERN HALF OF THE CWFA AND KEEP LOW CHANCE POPS GOING IN THE FAR SOUTH WHERE THUNDERSTORM DEVELOPMENT WILL BE DEPENDENT ON OUTFLOWS TO PROVIDE SOME FOCUS FOR TSRA INITIATION. ANY STORMS THAT DEVELOP SATURDAY SHOULD BE OF THE PULSE VARIETY WITH THE WEAK DEEP LAYER SHEAR IN PLACE. THE NAM WAS SHOWING CAPES EXCEEDING 3000 J/KG DURING THE AFTERNOON. IF THESE CAPES ARE REALIZED THEN SOME OF THE STRONGER STORMS WILL BE CAPABLE OF PRODUCING SOME STRONG WINDS GUSTS. KEPT SOME LOW POPS GOING FOR SATURDAY NIGHT WITH THE BOUNDARY STILL IN THE AREA AND CONTINUED SOME LOW POPS SOUTHEAST SUNDAY TO ACCOUNT FOR THE ECMWF SOLUTION WHICH HOLDS A WEAK BOUNDARY IN OUR SOUTHEAST DURING THE DAY. SUNDAY NIGHT AND MONDAY WARMER AIR POURS BACK TO INTO THE REGION AS UPPER RIDGING BUILDS EAST OUT OF THE ROCKIES. IT LOOKS LIKE WIDESPREAD 90S WILL RETURN TO THE REGION MONDAY AND TUESDAY WITH HEAT INDICES APPROACHING 100. WITH THE RIDGE BUILDING IN...A DRY FORECAST IS IN ORDER MONDAY AND MONDAY NIGHT. FOR TUESDAY THROUGH THURSDAY THE GFS/ECMWF CONTINUE TO SHOW A S/W MOVING THROUGH THE NORTHERN TIER OF STATES AND SUPPRESSING THE MIDWEST RIDGE. THE S/W WILL ALSO DROP ANOTHER BOUNDARY SOUTH INTO THE REGION. WITH THE GFS/ECMWF HOLDING THE BOUNDARY JUST SOUTH OF THE AREA INTO THURSDAY WILL KEEP SOME LOW POPS GOING TUESDAY THROUGH THURSDAY...BUT HOLD THEM IN THE SLIGHT CHANCE/LOW CHANCE RANGE SINCE MODELS KEEP MID LEVEL TEMPS ON THE WARM SIDE NEAR THE BOUNDARY. IF THE GFS/ECMWF PROGS VERIFY THEN A SURFACE HIGH SETTING UP OVER THE WESTERN GREAT LAKES SHOULD KEEP EAST/NORTHEAST LOW LEVEL FLOW OVER THE AREA FOR MID/LATE WEEK. TEMPERATURES TUESDAY SHOULD STILL BE IN THE 90S AS THE FRONT MOVES THROUGH THEN INCREASING EAST OR NORTHEAST FLOW WEDNESDAY INTO THURSDAY SHOULD TAKE THE EDGE OFF THE HEAT. DLF && .AVIATION... ELEVATED CONVECTION HAS DEVELOPED IN RESPONSE TO AN UPPER LEVEL DISTURBANCE. KCID IS BEING AFFECTED WITH KDBQ/KMLI POSSIBLY BEING AFFECTED AS WELL. MVFR CONDITIONS THAT MAY BRIEFLY DROP TO IFR ARE EXPECTED. ISOLATED TO SCATTERED CONVECTION IS EXPECTED TO PERSIST THROUGH 00Z/14 AND POSSIBLY BEYOND. WHEN TSRA OR VCTS IS NOT AFFECTING A TAF SITE...VFR CONDITIONS ARE EXPECTED. 08 && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
333 AM CDT FRI JUL 13 2012 .SYNOPSIS... 06Z SFC ANALYSIS HAS HIGH PRESSURE OVER THE EASTERN GREAT LAKES WITH TWO TROFS ACROSS THE PLAINS. DEW POINTS WERE IN THE 50S ACROSS THE IMMEDIATE GREAT LAKES WITH 60S OVER MOST OF THE MIDWEST. && .SHORT TERM...ODAY AND TONIGHT... SATELLITE TRENDS THE PAST SEVERAL HOURS HAS HAD CONSIDERABLE DEVELOPMENT OF MID LEVEL CLOUDS. RADAR IN TURN HAS ALSO DEVELOPED ELEVATED ISOLATED TO SCATTERED CONVECTION ACROSS IOWA. RAP TRENDS AND THE LIFT TOOL HAVE BEEN QUITE USEFUL IN DEPICTING THE CURRENT CONVECTION. THE LIFT TOOL SHOWS WEAK THETA E GRADIENTS WORKING IN CONCERT WITH CONVERGENCE TO PRODUCE THE CONVECTION. RUC TRENDS PERSIST THIS ACROSS ROUGHLY THE NORTHWEST TWO THIRDS OF THE CWFA DURING THE MORNING HOURS IN ASSOCIATION WITH THE VORT MAX MOVING THROUGH IN THE FLOW ALOFT. INTERESTINGLY...THE VORT MAX SUDDENLY STRENGTHENS BY LATE MORNING WHICH MAY OR MAY NOT BE A CONVECTIVE FEEDBACK ISSUE WITH THE RAP MODEL. THE QUESTION THEN TURNS TO WHETHER OR NOT CONVECTION WILL DEVELOP DURING THE AFTERNOON HOURS. THE LIFT TOOL HAS NEGATIVE THETA E LAPSE RATES ACROSS THE AREA WITH SOME WEAK CONVERGENCE ALOFT. THE MAIN VARIABLE WILL BE HOW MUCH THE CLOUDS HOLD DOWN TEMPERATURES. CONVECTIVE TEMPERATURES ARE ESSENTIALLY IN THE UPPER 80S TO LOWER 90S WHICH IS THE FCST MAX TEMPERATURES. THUS WILL CONTINUE WITH ISOLATED TO SCATTERED CONVECTION DURING THE AFTERNOON. ANY DIURNAL CONVECTION THAT DEVELOPS THIS AFTERNOON WILL CONTINUE INTO THE EARLY EVENING AND SHOULD DISSIPATE SHORTLY AFTER SUNSET. HOWEVER...ANOTHER VORT MAX IN THE FLOW IS JUST UPSTREAM SO CONVECTION COULD PERSIST LATER INTO THE EVENING...OR...RE-DEVELOP AROUND MIDNIGHT AND THEN PERSIST THROUGH THE NIGHT. GIVEN THE WEAK CHARACTERISTICS OF THE FLOW ALOFT...THE SECOND SCENARIO WOULD SEEM MORE PLAUSIBLE. INDEED THE LIFT TOOL DOES SUGGEST ANOTHER THETA E GRADIENT MOVING INTO THE CWFA AROUND MIDNIGHT. THUS...WILL GO WITH THE CONCEPT OF ISOLATED TO SCATTERED NOCTURNAL CONVECTION DEVELOPING AND THEN PERSISTING THROUGH SUNRISE. 08 .LONG TERM...SATURDAY THROUGH THURSDAY... THE LATEST MODEL RUNS CONTINUE TO DROP A WEAK BOUNDARY INTO THE REGION SATURDAY. THIS SHOULD GIVE AT LEAST THE NORTHERN HALF OF THE AREA A REASONABLE CHANCE OF SCATTERED THUNDERSTORMS ESPECIALLY WITH THE BOUNDARY SETTLING INTO THE NORTH DURING PRIME HEATING. WILL GO WITH 30/40 POPS FOR THE NORTHERN HALF OF THE CWFA AND KEEP LOW CHANCE POPS GOING IN THE FAR SOUTH WHERE THUNDERSTORM DEVELOPMENT WILL BE DEPENDENT ON OUTFLOWS TO PROVIDE SOME FOCUS FOR TSRA INITIATION. ANY STORMS THAT DEVELOP SATURDAY SHOULD BE OF THE PULSE VARIETY WITH THE WEAK DEEP LAYER SHEAR IN PLACE. THE NAM WAS SHOWING CAPES EXCEEDING 3000 J/KG DURING THE AFTERNOON. IF THESE CAPES ARE REALIZED THEN SOME OF THE STRONGER STORMS WILL BE CAPABLE OF PRODUCING SOME STRONG WINDS GUSTS. KEPT SOME LOW POPS GOING FOR SATURDAY NIGHT WITH THE BOUNDARY STILL IN THE AREA AND CONTINUED SOME LOW POPS SOUTHEAST SUNDAY TO ACCOUNT FOR THE ECMWF SOLUTION WHICH HOLDS A WEAK BOUNDARY IN OUR SOUTHEAST DURING THE DAY. SUNDAY NIGHT THROUGH TUESDAY WARMER AIR POURS BACK TO INTO THE REGION AS UPPER RIDGING BUILDS EAST OUT OF THE ROCKIES. IT LOOKS LIKE WIDESPREAD 90S WILL RETURN TO THE REGION MONDAY AND TUESDAY WITH HEAT INDICES APPROACHING 100. WITH THE RIDGE BUILDING IN...A DRY FORECAST IS IN ORDER. FOR WEDNESDAY AND THURSDAY THE GFS/ECMWF CONTINUE TO SHOW A S/W MOVING THROUGH THE NORTHERN TIER OF STATES AND SUPPRESSING THE MIDWEST RIDGE. THE S/W WILL ALSO DROP ANOTHER BOUNDARY SOUTH INTO THE REGION. WILL KEEP SOME LOW POPS GOING WEDNESDAY THROUGH THURSDAY... BUT HOLD THEM IN THE SLIGHT CHANCE/LOW CHANCE RANGE SINCE MODELS KEEP MID LEVEL TEMPS ON THE WARM SIDE NEAR THE BOUNDARY. IF THE GFS/ECMWF PROGS VERIFY THEN A SURFACE HIGH SETTING UP OVER THE WESTERN GREAT LAKES SHOULD KEEP EAST/NORTHEAST LOW LEVEL FLOW OVER THE AREA...TAKING THE EDGE OFF THE HEAT FOR THE END OF THE WEEK. DLF && .AVIATION... ELEVATED CONVECTION HAS DEVELOPED IN RESPONSE TO AN UPPER LEVEL DISTURBANCE. KCID IS BEING AFFECTED WITH KDBQ/KMLI POSSIBLY BEING AFFECTED AS WELL. MVFR CONDITIONS THAT MAY BRIEFLY DROP TO IFR ARE EXPECTED. ISOLATED TO SCATTERED CONVECTION IS EXPECTED TO PERSIST THROUGH 00Z/14 AND POSSIBLY BEYOND. WHEN TSRA OR VCTS IS NOT AFFECTING A TAF SITE...VFR CONDITIONS ARE EXPECTED. 08 && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
606 PM CDT SAT JUL 14 2012 ...UPDATE TO AVIATION... .SHORT TERM...(THIS EVENING THROUGH TOMORROW) ISSUED AT 304 PM CDT SAT JUL 14 2012 A RIDGE OF UPPER LEVEL HIGH PRESSURE WILL DOMINATE THE HIGH PLAINS FROM NEW MEXICO INTO WESTERN KANSAS AND NEBRASKA INTO SUNDAY. A LEE TROUGH OF LOW PRESSURE WILL ALSO REMAIN IN EASTERN COLORADO WITH LIGHT SOUTH TO SOUTHEAST WINDS TONIGHT. THE PRESSURE GRADIENT THEN TIGHTENS ON SUNDAY WITH SOUTH TO SOUTHWEST WINDS OF 15 TO 25 MPH AND GUSTY. A MID LEVEL CAPPING INVERSION WILL ALSO CONTINUE INTO SUNDAY AFTERNOON, AND WITH TEMPERATURES APPROACHING 100, THE CAP MAY WEAKEN ENOUGH TO SUPPORT SOME HIGH BASED THUNDERSTORMS LATE THIS AFTERNOON INTO EARLY EVENING AND AGAIN ON SUNDAY. WILL ADD A SLIGHT CHANCE OF THUNDER MAINLY EAST OF A LINE FROM WAKEENEY TO MEADE. WITH DEWPOINTS ALSO MIXING OUT, IF ANY THUNDERSTORMS FORM, THEY COULD PUT OUT SOME LOCALLY STRONG GUSTS FROM 40 TO 50 MPH. THE HRRR MESOSCALE MODEL ALSO SUPPORTS A FEW THUNDERSTORMS LATE THIS AFTERNOON AND EARLY EVENING. OVERNIGHT LOWS WILL BE MILD AND IN THE MID TO UPPER 60S UNDER MOSTLY CLEAR SKIES. FOR SUNDAY EXPECT HIGHS NEAR THE CENTURY MARK WITH MOSTLY CLEAR TO PARTLY CLOUDY SKIES. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 435 PM CDT SAT JUL 14 2012 THERE WERE LITTLE OVERALL CHANGES IN EXPECTATIONS NOTED FOR THE EXTENDED FORECAST PERIOD. THE GENERAL PATTERN CONTINUES TO INDICATE A WEAKLY POSITIVE TILTED UPPER RIDGE BUILDING INTO THE GREAT PLAINS. THE RIDGE BECOMES SLOWLY FLATTENED WITH TIME AS SHORTWAVES RIDE THE NORTHERN PERIPHERY OF THIS RIDGE THROUGH THE WEEK. THIS WARM AIRMASS WILL BE MARKED BY WARM TEMPERATURES IN THE MID TO UPPER 90S, AND TEMPERATURES AROUND 100 DEGREES BY MID TO LATE WEEK. CAPPING IS WEAK, ESPECIALLY ACROSS CENTRAL KANSAS WHERE 700 MB TEMPERATURES ARE UNDER 10 DEGREES C. AN ISOLATED BRIEF AIRMASS THUNDERSTORM CANNOT BE COMPLETELY RULED OUT ANY DAY, BUT CHANCES ARE QUITE LOW GIVEN THE LACK OF NOTED SURFACE CONVERGENCE. THE BEST CHANCES MIGHT BE FARTHER WEST AND SOUTH ON THE HIGHER TERRAIN OF THE PANHANDLES AND EASTERN COLORADO. SOUTHWEST KANSAS SHOULD REMAIN IN A WARM SECTOR THROUGH HE ENTIRE PERIOD, WHILE A STATIONARY FRONT RUNNING FROM IOWA THROUGH NEBRASKA AND SOUTH DAKOTA SHOULD BE A FOCUS FOR MESOSCALE CONVECTIVE SYSTEMS EACH NIGHT THROUGH THE MID TO LATE WEEK, AND REMAIN FOCUSED WELL AWAY FROM CENTRAL KANSAS. CONVECTIVE STORMS THAT DEVELOP FARTHER WEST WILL HAVE POOR STEERING FLOW WITH SUCH LIGHT MEAN WINDS DUE TO THE UPPER HIGH. THE ATMOSPHERE WILL PROBABLY BE MORE CONDUCIVE TO HEAT BURSTS AND GUSTY WINDS THAN TO SEVERE THUNDERSTORMS, ESPECIALLY WEST OF HIGHWAY 283 TO THE COLORADO LINE. TEMPERATURES BY LATE IN THE WEEK WERE RAISED A FEW DEGREES. SOME OF THE BIAS CORRECTED MODEL OUTPUT STATISTICS GUIDANCE IS SUPPORTIVE OF WARMER HIGHS UNDER THE UPPER RIDGE BY FRIDAY AND SATURDAY. WIDESPREAD TEMPERATURES IN EXCESS OF 100 DEGREES AND POSSIBLY TO AROUND 105 ARE INDICATED BY THIS GUIDANCE, AND SEEMS QUITE REASONABLE. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING) ISSUED AT 600 PM CDT SAT JUL 14 2012 VFR CONDITIONS WILL PREVAIL AT ALL TAF SITES THROUGH EARLY SUNDAY AFTERNOON. AS FOR WINDS, A LEE SIDE TROUGH OF LOW PRESSURE WILL REMAIN ENTRENCHED ACROSS EASTERN COLORADO THROUGH SUNDAY AFTERNOON. AS A RESULT, LIGHT SOUTHERLY WINDS EARLY THIS EVENING WILL CONTINUE OVERNIGHT THEN INCREASE SOMEWHAT TO AROUND 15 TO 25KT BY LATE SUNDAY MORNING AS DAYTIME HEATING INCREASES. && .PRELIMINARY POINT TEMPS/POPS... DDC 69 100 72 97 / 10 10 0 10 GCK 68 100 70 98 / 10 10 0 0 EHA 68 98 68 99 / 10 10 10 10 LBL 70 100 70 99 / 10 10 0 10 HYS 68 101 71 98 / 10 10 0 10 P28 72 99 72 96 / 20 10 0 0 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...KRUSE LONG TERM...RUSSELL AVIATION...JJOHNSON
AREA FORECAST DISCUSSION
NWS TOPEKA KS
102 PM CDT FRI JUL 13 2012 ...UPDATE TO AVIATION... .DISCUSSION... 0Z UPPER AIR DATA HAD A FEW WESTERLY 60-65KT REPORTS AT 250MB IN IDAHO AND WYOMING ROUNDING THE TOP OF THE WESTERN CONUS UPPER RIDGE. NEARBY MID LEVELS REMAIN ON THE COOL AND DAMP SIDE CONSIDERING LOWER LEVEL CONDITIONS OF HIGHS REACHING THE MIDDLE AND UPPER 90S AND DEWPOINTS PRIMARILY IN THE LOWER AND MIDDLE 60S. ISOLATED CONVECTION CONTINUES TO IMPACT EAST CENTRAL KANSAS AT 07Z WHERE MID CLOUD HAS AGAIN PREVAILED THROUGH THE NIGHT. UPSTREAM PRECIPITATION IN NEBRASKA HAS SLOWLY DIMINISHED THOUGH SOME RECENT REDEVELOPMENT IS NOTED IN NORTHEASTERN SECTIONS OF THAT STATE. MODELS CONTINUE TO BE CONSISTENT WITH RESPECTABLE MID-SUMMER UPPER DYNAMICS WORKING THEIR WAY SOUTHEAST INTO EASTERN KANSAS TODAY. ROCKIES UPPER JET TO DIVE SOUTHEAST INTO CENTRAL KANSAS WHILE POTENTIAL VORTICITY ANOMALY REACHES NORTHERN KANSAS BY MIDDAY WITH SOME UPPER LEVEL Q-VECTOR CONVERGENCE RESULTING. THESE FEATURES REACH THE 2-4C 700MB DEWPOINTS AND THE BULK OF THE GUIDANCE...INCLUDING THE LAST SEVERAL RUNS OF THE HRRR AND THE 06Z NAM...EXPANDS PRECIP COVERAGE BY 18Z AS A RESULT. STRENGTH OF PRECIPITATION IS SOMEWHAT IN QUESTION AS THE EARLY TIMING OF THE FORCING MAY KEEP STRONG INSOLATION IN CHECK AND MIXED-LAYER CAPE LIMITED. LARGER SCALE FORCING NOT REACHING EAST CENTRAL KANSAS UNTIL LATER IN THE DAY WOULD SUGGEST THIS AREA COULD HAVE THE GREATER POTENTIAL FOR STRONGER STORMS...BUT THIS WILL DEPEND ON HOW LONG THE ONGOING PRECIP LASTS. HAVE INCREASED POPS WELL ABOVE CLIMO LEVELS BUT HELD OFF ON ANYTHING ABOVE CHANCE GIVEN COVERAGE UNCERTAINTY. TEMPERATURES ARE ALSO A CHALLENGE...AND FIRST PERIOD SREF SPREADS ARE RATHER HIGH. WILL KEEP EASTERN AREAS A FEW DEGREES BELOW THURSDAYS LEVELS WITH AT LEAST MORE CLOUD EXPECTED IN LIGHT SYNOPTIC WINDS. PRECIP CONVERGE SHOULD TAPER FROM NORTHWEST TO SOUTHEAST IN THE LATE AFTERNOON AND EVENING AS THE FORCING MOVES OFF...BUT NOT EXPECTING A LOT OF CHANGE TO PROFILES...SUGGESTING SOME CHANCE FOR ELEVATED CONVECTION COULD LINGER AT LEST INTO THE EVENING. BEYOND TONIGHT...PRECIP CHANCES ARE ON THE LOW SIDE AS THE WESTERN RIDGE BUILDS INTO THE PLAINS. HARD TO COMPLETELY RULE OUT MORE EVENTS OF ISOLATED ACTIVITY...BUT HARD TO JUSTIFY A MENTION AT THIS POINT. CONVERGENCE NEAR A STALLING FRONT IN NEBRASKA APPEARS WEAK AT BEST FOR SATURDAY AND GETTING ANYTHING TO SURVIVE INTO KANSAS IS UNLIKELY. THE GFS ATTEMPTS TO BRING A FRONT SOUTH TO NEAR THE KANSAS BORDER EARLY NEXT WEEK...BUT THE ECMWF KEEPS IT NORTH. MUCH TOO LITTLE CONFIDENCE FOR A MENTION WITH THIS POSSIBILITY AT THIS POINT. AS FOR TEMPERATURES...850MB TEMPS WARM A BIT FURTHER SATURDAY WITH UPPER 90S TO AROUND 100 COMMONPLACE. INCREASED LOW LEVEL SOUTHEAST FLOW MAY TONE DOWN TEMPS SUNDAY...BUT A MORE WESTERLY COMPONENT SHOULD PUSH HIGHS BACK UP TO AROUND 100 FOR MUCH OF NEXT WEEK. HUMIDITIES STILL DONT LOOK TOO BAD...BUT THE APPEARS TO BE SOME POTENTIAL FOR HEAT HEADLINES DUE TO HEATS PERSISTENCE. 65 && .AVIATION... SHOWERS NEAR KTOP AND KFOE WILL DEPART THE AREA SHORTLY...WITH SKIES GRADUALLY CLEARING UP. MODEL GUIDANCE SUGGESTS FOG FORMATION AT THE TERMINALS OVERNIGHT...HOWEVER GIVEN THE DRY ATMOSPHERE IN THE LOWEST 10KFT WILL OPT TO NOT INCLUDE FOG MENTION FOR TONIGHT. HOWEVER...WITH THE RAINFALL FROM TODAY THERE IS A POSSIBILITY THAT SOME SHALLOW GROUND FOG MAY OCCUR...BUT WITH CERTAINTY RATHER LOW WILL HANDLE THE FOG THREAT WITH FUTURE FORECASTS AND AMENDMENTS. JL && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
652 AM CDT FRI JUL 13 2012 ...UPDATE TO AVIATION... .DISCUSSION... 0Z UPPER AIR DATA HAD A FEW WESTERLY 60-65KT REPORTS AT 250MB IN IDAHO AND WYOMING ROUNDING THE TOP OF THE WESTERN CONUS UPPER RIDGE. NEARBY MID LEVELS REMAIN ON THE COOL AND DAMP SIDE CONSIDERING LOWER LEVEL CONDITIONS OF HIGHS REACHING THE MIDDLE AND UPPER 90S AND DEWPOINTS PRIMARILY IN THE LOWER AND MIDDLE 60S. ISOLATED CONVECTION CONTINUES TO IMPACT EAST CENTRAL KANSAS AT 07Z WHERE MID CLOUD HAS AGAIN PREVAILED THROUGH THE NIGHT. UPSTREAM PRECIPITATION IN NEBRASKA HAS SLOWLY DIMINISHED THOUGH SOME RECENT REDEVELOPMENT IS NOTED IN NORTHEASTERN SECTIONS OF THAT STATE. MODELS CONTINUE TO BE CONSISTENT WITH RESPECTABLE MID-SUMMER UPPER DYNAMICS WORKING THEIR WAY SOUTHEAST INTO EASTERN KANSAS TODAY. ROCKIES UPPER JET TO DIVE SOUTHEAST INTO CENTRAL KANSAS WHILE POTENTIAL VORTICITY ANOMALY REACHES NORTHERN KANSAS BY MIDDAY WITH SOME UPPER LEVEL Q-VECTOR CONVERGENCE RESULTING. THESE FEATURES REACH THE 2-4C 700MB DEWPOINTS AND THE BULK OF THE GUIDANCE...INCLUDING THE LAST SEVERAL RUNS OF THE HRRR AND THE 06Z NAM...EXPANDS PRECIP COVERAGE BY 18Z AS A RESULT. STRENGTH OF PRECIPITATION IS SOMEWHAT IN QUESTION AS THE EARLY TIMING OF THE FORCING MAY KEEP STRONG INSOLATION IN CHECK AND MIXED-LAYER CAPE LIMITED. LARGER SCALE FORCING NOT REACHING EAST CENTRAL KANSAS UNTIL LATER IN THE DAY WOULD SUGGEST THIS AREA COULD HAVE THE GREATER POTENTIAL FOR STRONGER STORMS...BUT THIS WILL DEPEND ON HOW LONG THE ONGOING PRECIP LASTS. HAVE INCREASED POPS WELL ABOVE CLIMO LEVELS BUT HELD OFF ON ANYTHING ABOVE CHANCE GIVEN COVERAGE UNCERTAINTY. TEMPERATURES ARE ALSO A CHALLENGE...AND FIRST PERIOD SREF SPREADS ARE RATHER HIGH. WILL KEEP EASTERN AREAS A FEW DEGREES BELOW THURSDAYS LEVELS WITH AT LEAST MORE CLOUD EXPECTED IN LIGHT SYNOPTIC WINDS. PRECIP CONVERGE SHOULD TAPER FROM NORTHWEST TO SOUTHEAST IN THE LATE AFTERNOON AND EVENING AS THE FORCING MOVES OFF...BUT NOT EXPECTING A LOT OF CHANGE TO PROFILES...SUGGESTING SOME CHANCE FOR ELEVATED CONVECTION COULD LINGER AT LEST INTO THE EVENING. BEYOND TONIGHT...PRECIP CHANCES ARE ON THE LOW SIDE AS THE WESTERN RIDGE BUILDS INTO THE PLAINS. HARD TO COMPLETELY RULE OUT MORE EVENTS OF ISOLATED ACTIVITY...BUT HARD TO JUSTIFY A MENTION AT THIS POINT. CONVERGENCE NEAR A STALLING FRONT IN NEBRASKA APPEARS WEAK AT BEST FOR SATURDAY AND GETTING ANYTHING TO SURVIVE INTO KANSAS IS UNLIKELY. THE GFS ATTEMPTS TO BRING A FRONT SOUTH TO NEAR THE KANSAS BORDER EARLY NEXT WEEK...BUT THE ECMWF KEEPS IT NORTH. MUCH TOO LITTLE CONFIDENCE FOR A MENTION WITH THIS POSSIBILITY AT THIS POINT. AS FOR TEMPERATURES...850MB TEMPS WARM A BIT FURTHER SATURDAY WITH UPPER 90S TO AROUND 100 COMMONPLACE. INCREASED LOW LEVEL SOUTHEAST FLOW MAY TONE DOWN TEMPS SUNDAY...BUT A MORE WESTERLY COMPONENT SHOULD PUSH HIGHS BACK UP TO AROUND 100 FOR MUCH OF NEXT WEEK. HUMIDITIES STILL DONT LOOK TOO BAD...BUT THE APPEARS TO BE SOME POTENTIAL FOR HEAT HEADLINES DUE TO HEATS PERSISTENCE. 65 && .AVIATION... SCATTERED THUNDERSTORMS WILL PREVAIL FOR MUCH OF THE DAY AS A SHORT WAVE MOVES SOUTHEAST ACROSS NORTHEAST KANSAS THROUGH THE DAY. AFTER 22Z CONVECTION SHOULD COME TO AN END AS THE FORCING WITH THE WAVE SHIFTS TO THE EAST. MAINLY STAYED WITH VCTS...BUT DID GO WITH A TEMPO FOR TOP BETWEEN 13Z-15Z WITH MVFR VSBYS AND ALSO CIGS WITH HEAVIER RAIN ARE POSSIBLE. VFR EXPECTED OUTSIDE OF THE CONVECTION. 53 && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
321 AM CDT FRI JUL 13 2012 .DISCUSSION... 0Z UPPER AIR DATA HAD A FEW WESTERLY 60-65KT REPORTS AT 250MB IN IDAHO AND WYOMING ROUNDING THE TOP OF THE WESTERN CONUS UPPER RIDGE. NEARBY MID LEVELS REMAIN ON THE COOL AND DAMP SIDE CONSIDERING LOWER LEVEL CONDITIONS OF HIGHS REACHING THE MIDDLE AND UPPER 90S AND DEWPOINTS PRIMARILY IN THE LOWER AND MIDDLE 60S. ISOLATED CONVECTION CONTINUES TO IMPACT EAST CENTRAL KANSAS AT 07Z WHERE MID CLOUD HAS AGAIN PREVAILED THROUGH THE NIGHT. UPSTREAM PRECIPITATION IN NEBRASKA HAS SLOWLY DIMINISHED THOUGH SOME RECENT REDEVELOPMENT IS NOTED IN NORTHEASTERN SECTIONS OF THAT STATE. MODELS CONTINUE TO BE CONSISTENT WITH RESPECTABLE MID-SUMMER UPPER DYNAMICS WORKING THEIR WAY SOUTHEAST INTO EASTERN KANSAS TODAY. ROCKIES UPPER JET TO DIVE SOUTHEAST INTO CENTRAL KANSAS WHILE POTENTIAL VORTICITY ANOMALY REACHES NORTHERN KANSAS BY MIDDAY WITH SOME UPPER LEVEL Q-VECTOR CONVERGENCE RESULTING. THESE FEATURES REACH THE 2-4C 700MB DEWPOINTS AND THE BULK OF THE GUIDANCE...INCLUDING THE LAST SEVERAL RUNS OF THE HRRR AND THE 06Z NAM...EXPANDS PRECIP COVERAGE BY 18Z AS A RESULT. STRENGTH OF PRECIPITATION IS SOMEWHAT IN QUESTION AS THE EARLY TIMING OF THE FORCING MAY KEEP STRONG INSOLATION IN CHECK AND MIXED-LAYER CAPE LIMITED. LARGER SCALE FORCING NOT REACHING EAST CENTRAL KANSAS UNTIL LATER IN THE DAY WOULD SUGGEST THIS AREA COULD HAVE THE GREATER POTENTIAL FOR STRONGER STORMS...BUT THIS WILL DEPEND ON HOW LONG THE ONGOING PRECIP LASTS. HAVE INCREASED POPS WELL ABOVE CLIMO LEVELS BUT HELD OFF ON ANYTHING ABOVE CHANCE GIVEN COVERAGE UNCERTAINTY. TEMPERATURES ARE ALSO A CHALLENGE...AND FIRST PERIOD SREF SPREADS ARE RATHER HIGH. WILL KEEP EASTERN AREAS A FEW DEGREES BELOW THURSDAYS LEVELS WITH AT LEAST MORE CLOUD EXPECTED IN LIGHT SYNOPTIC WINDS. PRECIP CONVERGE SHOULD TAPER FROM NORTHWEST TO SOUTHEAST IN THE LATE AFTERNOON AND EVENING AS THE FORCING MOVES OFF...BUT NOT EXPECTING A LOT OF CHANGE TO PROFILES...SUGGESTING SOME CHANCE FOR ELEVATED CONVECTION COULD LINGER AT LEST INTO THE EVENING. BEYOND TONIGHT...PRECIP CHANCES ARE ON THE LOW SIDE AS THE WESTERN RIDGE BUILDS INTO THE PLAINS. HARD TO COMPLETELY RULE OUT MORE EVENTS OF ISOLATED ACTIVITY...BUT HARD TO JUSTIFY A MENTION AT THIS POINT. CONVERGENCE NEAR A STALLING FRONT IN NEBRASKA APPEARS WEAK AT BEST FOR SATURDAY AND GETTING ANYTHING TO SURVIVE INTO KANSAS IS UNLIKELY. THE GFS ATTEMPTS TO BRING A FRONT SOUTH TO NEAR THE KANSAS BORDER EARLY NEXT WEEK...BUT THE ECMWF KEEPS IT NORTH. MUCH TOO LITTLE CONFIDENCE FOR A MENTION WITH THIS POSSIBILITY AT THIS POINT. AS FOR TEMPERATURES...850MB TEMPS WARM A BIT FURTHER SATURDAY WITH UPPER 90S TO AROUND 100 COMMONPLACE. INCREASED LOW LEVEL SOUTHEAST FLOW MAY TONE DOWN TEMPS SUNDAY...BUT A MORE WESTERLY COMPONENT SHOULD PUSH HIGHS BACK UP TO AROUND 100 FOR MUCH OF NEXT WEEK. HUMIDITIES STILL DONT LOOK TOO BAD...BUT THE APPEARS TO BE SOME POTENTIAL FOR HEAT HEADLINES DUE TO HEATS PERSISTENCE. 65 && .AVIATION... THE NAM AND GFS ARE A LITTLE MORE AGGRESSIVE IN SHOWING SOME MID LEVEL ISENTROPIC LIFT THROUGH THE NIGHT AND ISOLATED PRECIP SPREADING INTO NORTHEAST KS AS A WEAK DISTURBANCE MOVES THROUGH SOUTHERN NEB. CONFIDENCE IN LOCATION AND COVERAGE IS LOW. HOWEVER LATEST RUNS OF THE HRRR SUGGEST SCT TS MAY BE POSSIBLE ACROSS NORTHEAST KS BEFORE 12Z. IN ANY CASE ODDS ARE THAT VFR CONDITIONS WILL PREVAIL. IF STORMS DEVELOP THERE COULD BE A BRIEF 15 TO 30 MINUTE WINDOW OF REDUCED VSBY. WITH LOW CONFIDENCE AND LOW SKILL IN FORECASTING CONVECTIVE DETAILS...WILL OPT TO KEEP A VFR FORECAST AND MONITOR TRENDS FOR POSSIBLE ADDITION OF A TEMPO FOR MVFR VSBY AND TS. WOLTERS && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1045 PM MDT THU JUL 12 2012 .SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT) ISSUED AT 146 PM MDT THU JUL 12 2012 SURFACE TROUGH IS STARTING TO PUSH INTO THE WESTERN PORTION OF THE AREA WITH A SHORTWAVE MOVING OVER THE TOP OF IT BEGINNING THIS AFTERNOON. DECENT SURFACE CONVERGENCE ALONG IT WITH LITTLE TO NO INHIBITION. SO DO EXPECT THUNDERSTORMS TO DEVELOP BUT HOW FAR EAST TO TAKE THEM IS A QUESTION. STORM MOVEMENTS NEAR 15 KNOTS SO THEY SHOULD MAKE SOME PROGRESS. EARLIER MODEL OUTPUT WAS NOT TOTALLY EXCITED ABOUT GENERATING PRECIPITATION ACROSS CWA THROUGH TONIGHT. HOWEVER...THE LATEST HRRR IS GENERATING SOME LIGHT QPF. WITH THE AMOUNT OF INSTABILITY AND LIFT BELIEVE THERE IS ENOUGH THERE TO HAVE A SLIGHT CHANCE THROUGH THE ENTIRE NIGHT. SO GRIDS WERE ADJUSTED ACCORDINGLY THROUGH TONIGHT. WINDS LOOK TO BECOME LIGHT AND CLOUDS DECREASE AFTER WHATEVER CONVECTION THERE IS IS DONE. DEPENDING ON HOW LOW THE DEWPOINTS ARE...TEMPERATURES COULD DROP A LITTLE...ESPECIALLY IN THE WEST. LOOK TO HAVE PLENTY OF SUN TOMORROW WITH MODELS SHOWING A RATHER CHAOTIC WIND FIELD...MOSTLY FROM AN EASTERLY DIRECTION. NAM 2M/NWP HAS BEEN DOING WELL IN THIS HOT PATTERN AND THINK IT IS ON THE RIGHT TRACK. GFS STILL LOOKS TOO MOIST AND COOL IN THE LOWER LEVELS. SO BASED ON THE NAM 2M/NWP AND 850 MB TEMPERATURE CONCENSUS...RAISED MAXES FOR FRIDAY TO NEAR 100 FOR MANY LOCATIONS. MUCH WARMER AND DRIER AT MID LEVELS LOOKS TO KEEP IT DRY TOMORROW AS WELL. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 240 PM MDT THU JUL 12 2012 AT THE START OF THE EXTENDED PERIOD...THE UPPER HIGH NOW OVER UTAH WILL HAVE MIGRATED TO THE CO-NM AREA AS THE LARGE SCALE UPPER TROUGH BECOMES ESTABLISHED IN THE WEST. THE UPPER HIGH WILL BE THE DOMINANT PLAYER IN OUR WEATHER AS IT STALLS OVER THE CENTRAL PLAINS EARLY NEXT WEEK. WITH WEAK FLOW ALOFT AND LACK OF SURFACE FEATURES TO FOCUS CONVECTION...THUNDERSTORM POTENTIAL DURING THIS PERIOD WILL BE ISOLATED AT BEST. BOTH THE GFS AND ECMWF SUGGEST THE POTENTIAL FOR INCREASING THUNDERSTORM COVERAGE IN DAYS 6 AND 7 AS A CANADIAN SURFACE HIGH BUILDS SOUTH AND STALLS CLOSE TO OUR FORECAST AREA. IF THIS SCENARIO DOES UNFOLD THEN POPS IN THE FAR EXTENDED PERIODS WILL NEED TO BE ADJUSTED UPWARD. DAY-TO-DAY TEMPERATURE CHANGES ARE EXPECTED TO BE INSIGNIFICANT. MODELS FORECAST 850 TEMPS AROUND 30-32C THROUGH THE PERIOD WHICH WILL TRANSLATE TO HIGHS IN THE MID 90S TO NEAR 100 DEGREES. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 1038 PM MDT THU JUL 12 2012 THE CURRENT RADAR TREND INDICATES THAT STORMS SHOULD MOVE PAST KMCK PRIOR TO 06Z AND THE REST OF THE NIGHT SHOULD BE QUIET. THE NAM HAS A GOOD HANDLE ON CURRENT ACTIVITY AND DOES NOT BRING ANY STORMS INTO KGLD OVERNIGHT. THEREFORE EXPECT VFR CONDITIONS AND LIGHT SOUTHEAST WIND FOR THE NEXT 24 HOURS AS HIGH PRESSURE ALOFT CONTINUES OVER THE ROCKIES. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...BULLER LONG TERM...DLF AVIATION...FS
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1138 PM CDT THU JUL 12 2012 .DISCUSSION... SEE PREV DISCUSSION. && .AVIATION... THE NAM AND GFS ARE A LITTLE MORE AGGRESSIVE IN SHOWING SOME MID LEVEL ISENTROPIC LIFT THROUGH THE NIGHT AND ISOLATED PRECIP SPREADING INTO NORTHEAST KS AS A WEAK DISTURBANCE MOVES THROUGH SOUTHERN NEB. CONFIDENCE IN LOCATION AND COVERAGE IS LOW. HOWEVER LATEST RUNS OF THE HRRR SUGGEST SCT TS MAY BE POSSIBLE ACROSS NORTHEAST KS BEFORE 12Z. IN ANY CASE ODDS ARE THAT VFR CONDITIONS WILL PREVAIL. IF STORMS DEVELOP THERE COULD BE A BRIEF 15 TO 30 MINUTE WINDOW OF REDUCED VSBY. WITH LOW CONFIDENCE AND LOW SKILL IN FORECASTING CONVECTIVE DETAILS...WILL OPT TO KEEP A VFR FORECAST AND MONITOR TRENDS FOR POSSIBLE ADDITION OF A TEMPO FOR MVFR VSBY AND TS. WOLTERS && .PREV DISCUSSION.../ISSUED 341 PM CDT THU JUL 12 2012/ SHORT TERM - THROUGH FRIDAY...ISOLATED THUNDERSTORMS HAVE DEVELOPED IN THE EASTERN HALF OF THE FORECAST AREA THIS AFTERNOON IN A ZONE OF WEAK LOW LEVEL CONVERGENT FLOW WITH A HINT OF ASCENT ALOFT COURTESY OF A VERY WEAK SHORT WAVE TROUGH. INSTABILITY WAS ON THE ORDER OF 1000 TO 2000 J/KG...AND DEEP LAYER SHEAR IS ON THE ORDER OF 10 KTS SO THE END RESULT IS A VERY PULSE-LIKE STORM MODE WITH CELLS QUICK TO GO UP AND QUICK TO COLLAPSE. THERE IS A RATHER DEEP LAYER OF DRY ADIABATIC LAPSE RATES IN THE LOW LEVELS SO THE STRONGER STORMS HAVE PUT OUT SOME WIND GUSTS IN THE 40 TO 50 MPH RANGE. THIS ISOLATED ACTIVITY SHOULD CONTINUE THROUGH MID TO LATE AFTERNOON WITH A GRADUAL DECREASING TREND LIKELY AS OUTFLOW STABILIZES THE BOUNDARY LAYER BIT BY BIT. THERE IS SOME POTENTIAL FOR REDEVELOPMENT BETWEEN 22Z AND 02Z IN FAR NORTHERN KANSAS AS A SLIGHTLY STRONGER PIECE OF SHORT WAVE ENERGY MOVES INTO THE AREA FROM CENTRAL NEBRASKA. CONVECTIVE DEVELOPMENT DEPENDS LARGELY ON WHETHER THE MID/UPPER FORCING WILL ARRIVE BEFORE THE CAP STRENGTHENS. AT THE CURRENT TIME...IT APPEARS THAT A FEW STORMS WILL BE POSSIBLE THROUGH MID EVENING WITH ISOLATED STRONG WIND GUSTS ASSOCIATED WITH ANY STRONG STORMS. YET ANOTHER SHORT WAVE TROUGH WILL MOVE FROM THE DAKOTAS SOUTH INTO NORTHEAST KANSAS ON FRIDAY WITH ISOLATED TO SCATTERED STORMS EXPECTED JUST ABOUT ANY TIME DURING THE DAY. THE BEST CHANCES APPEAR TO BE IN NORTHEAST AND EAST CENTRAL KANSAS. THIS WILL BE A CONVECTIVE SET UP SIMILAR TO THURSDAY WITH SLIGHTLY MORE DEEP LAYER SHEAR AND A SLIGHTLY SHALLOWER DRY ADIABATIC LAYER. COULD SEE A FEW STRONG STORMS WITH ISOLATED HAIL OR STRONG WIND GUSTS. HIGH TEMPS WILL BE DEPENDENT UPON DAYTIME CLOUD COVER BUT WOULD EXPECT THE ENTIRE AREA TO HIT THE MIDDLE 90S WITH SOME HIGHER READINGS POSSIBLE IN AREAS WITH LESS CLOUDS. BARJENBRUCH SATURDAY THROUGH THURSDAY...EXPECT SHOWERS AND THUNDERSTORMS TO WIND DOWN ON FRIDAY NIGHT INTO SATURDAY MORNING...WITH THE BEST CHANCES FOR SHOWERS ENDING GRADUALLY FROM WEST TO EAST. THE WARMING TREND WILL CONTINUE THROUGH THE WEEKEND AND NEXT WORK WEEK AS 500 MB PRESSURE HEIGHTS WILL RISE...INDICATING THE PRESENCE OF THE UPPER LEVEL RIDGE. WITH SOUTHERLY FLOW AND AMPLE SUNSHINE EXPECT HIGHS TO REACH THE UPPER 90S TO LOWER 100S BY EARLY NEXT WEEK...WITH HOT TEMPERATURES LASTING THROUGH THE ENTIRE WEEK. WILL MAINTAIN A DRY FORECAST FOR THE REST OF THE WEEK GIVEN LACK OF ANY LOW LEVEL TRIGGERING MECHANISM AND UPPER LEVEL SUPPORT. LONG RANGE MODELS HINT AT THE POSSIBILITY OF A VERY WEAK BOUNDARY MOVING INTO NORTHEAST KANSAS BY THE WED/THU TIME PERIOD AND THIS BOUNDARY MAY BE ABLE TO KICK OFF SOME SHOWERS...BUT GIVEN HOW WEAK THE BOUNDARY LOOKS TO BE IT MAY STALL OUT NORTH OF THE FORECAST AREA. SHOULD THE BOUNDARY BE ABLE TO SLIDE SOUTH OF THE KS/NE BORDER SOME SLIGHT RELIEF FROM THE HEAT WOULD BE EXPERIENCED NORTH OF THE BOUNDARY. JL && .TOP WATCHES/WARNINGS/ADVISORIES...NONE. && $$
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
1100 PM EDT SAT JUL 14 2012 .UPDATE... ISSUED AT 1100 PM EDT SAT JUL 14 2012 CONVECTION HAS DISSIPATED WITH THE LOSS OF DAYTIME HEATING. OVERNIGHT... A LULL IN THE ACTIVITY IS EXPECTED...BUT 21Z SREF AND 0Z NAM SHOW CONVECTIVE DEVELOPMENT GENERALLY OVER WESTERN SECTIONS TOWARD DAWN IN ADVANCE OF AN APPROACHING SHORTWAVE. THE 18Z GFS IS RELATIVELY CONSISTENT WITH THIS IDEA AS WELL. THEREFORE WE HAVE CONTINUED WITH A LULL IN POPS OVER THE NEXT COUPLE OF HOURS AND THEN HAVE THEM INCREASING INTO THE ISOLATED TO SCATTERED RANGE LATE. SOME SLIGHT ADJUSTMENTS TO HOURLY TEMPS AND DEWPOINTS WERE ALSO MADE. UPDATED GRIDS AND ZFP ARE ALREADY OUT. UPDATE ISSUED AT 815 PM EDT SAT JUL 14 2012 CONVECTION CONTINUES TO WEAKEN AS WE APPROACH SUNSET...AND OVERALL INTENSITIES HAVE DIMINISHED OVER THE PAST HOUR OR SO. MEASURABLE RAIN CHANCES WILL BE HIGHEST INITIALLY FROM NEAR JKL TOWARD THE BIG SANDY REGION AS THE REMAINING CONVECTION WORKS EAST NORTHEAST AND GRADUALLY IS EXPECTED TO CONTINUE TO WEAKEN OVER THE NEXT TWO HOURS. POPS AND SKY WERE UPDATED ACCORDINGLY BASED ON THESE TRENDS. && .SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT) ISSUED AT 335 PM EDT SAT JUL 14 2012 19Z SFC ANALYSIS SHOWS A WEAK PRESSURE PATTERN THROUGHOUT EAST KENTUCKY WITH NO CLEAR SYNOPTIC SCALE FEATURES TO KEY IN ON. HOWEVER...GIVEN THE HIGH PW AIR IN PLACE...NO CAP...AND SOME UPPER LEVEL ENERGY...NOT MUCH WAS NEEDED TO INITIATE THE STORMS LATE THIS MORNING THAT CONTINUE TO PERCOLATE OVER THE CWA AT THIS HOUR. THE CLOUDS FILLED IN FROM THE SOUTH BY MID MORNING AND CONVECTION FOLLOWED SHORTLY THEREAFTER. A FEW OF THE CELLS HAVE GOTTEN STRONG AND OTHERS HAVE MERGED/TRAINED OVER THE SAME SPOTS CREATING A CONCERN FOR MINOR URBAN OR SMALL STREAM FLOODING. REGARDLESS...THE RAINS IN MANY LOCATIONS ARE NOW PUTTING A SERIOUS DENT IN THEIR ANNUAL RAINFALL DEFICIT THANKS TO THESE PAST FEW DAYS. TEMPERATURES THIS AFTERNOON HAVE BEEN HIGHLY DEPENDENT ON THE CONVECTIVE PATTERN AND BREAKS FOR SUNSHINE WITH READINGS CURRENTLY RANGING FROM THE LOW 70S IN THE RAIN COOLED SOUTHERN I-75 CORRIDOR TO MID 80S JUST SOUTH OF STORMS NEAR I-64 AND IN THE...THUS FAR RAIN FREE...FAR SOUTHEAST. DEWPOINTS...MEANWHILE...REMAIN PEGGED IN THE LOW TO MID 70S SUPPLYING ALL THE JUICE THE CONVECTION COULD NEED. THE MODELS REMAIN IN AGREEMENT THAT EAST KENTUCKY WILL BE ON THE FRINGE OF THE WESTERN EXTENT OF A WEAK BERMUDA RIDGE AND AHEAD OF TROUGHING COMING FROM THE NORTHERN PLAINS AND CROSSING THE GREAT LAKES ON SUNDAY. THE ENERGY FROM THIS TROUGH WILL PASS BY TO THE NORTH LATER SUNDAY AND THIS WILL SERVE TO FURTHER LIMIT THE EFFECT OF THE EASTERN RIDGE ON OUR WEATHER INTO THE START OF THE NEW WORK WEEK. IN THIS ENVIRONMENT THE MESOSCALE...OR SMALLER...WILL DOMINATE SO HAVE LEANED MOST HEAVILY ON THE DETAILS OF THE NAM12 WITH A HEALTHY DOSE OF THE HRRR EARLY ON TONIGHT. SENSIBLE WEATHER WILL FEATURE SHOWERS AND THUNDERSTORMS WINDING DOWN...FOR THE MOST PART...AFTER SUNSET...BUT NOT BEFORE LEAVING BEHIND A FAIR AMOUNT OF RAINFALL IN SEVERAL LOCATIONS. EXPECT A LULL THROUGH THE MIDDLE OF THE NIGHT WITH PATCHY FOG A GOOD BET. THE APPROACH OF A SHORTWAVE INTO THE OHIO VALLEY LATE TONIGHT GIVES SOME CREDENCE TO THE NAM12/S IDEA OF A CONVECTIVE CLUSTER FORMING OVER CENTRAL TENNESSEE AND DRIFTING INTO THE CUMBERLAND VALLEY BY DAWN. SOME SUPPORT FROM THE GFS BOLSTERS THIS IDEA...AS WELL. ACCORDINGLY... HAVE DEVIATED FROM A STRICTLY DIURNALLY DRIVEN POP AND WX PATTERN TO ALLOW FOR THIS IDEA IN THE GRIDS...THOUGH NOT WHOLE HOG JUST YET. OTHERWISE...EXPECT A NEAR REPEAT OF TODAY FOR SUNDAY WITH CONVECTION DRIVEN MAINLY BY DIURNAL HEATING AND MINOR OUTFLOWS/DIFFERENTIAL HEATING BOUNDARIES. FOR BOTH TONIGHT AND SUNDAY NIGHT HAVE BEEN GENEROUS WITH THE PATCHY FOG IN THE GRIDS AFTER MIDNIGHT...BUT HELD OFF ON ANY DENSE UNTIL IT BECOMES MORE APPARENT WHERE THE BEST NOCTURNAL CLEARING WILL OCCUR. FOR TEMPERATURES...FOLLOWED A BLEND OF THE INHERITED GRIDS... PERSISTENCE...AND SOME OF THE LATEST MET VALUES...AGAIN NOT MUCH IN THE WAY OF TERRAIN EFFECTS FOR LOWS GIVEN THE HIGH DEWPOINTS. AS FOR POPS...HAVE ENDED UP SIMILAR TO A BLEND OF THE MET AND MAV MOS THROUGHOUT THE PERIOD. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 340 PM EDT SAT JUL 14 2012 THE MODELS REMAIN IN VERY GOOD AGREEMENT WITH THE GENERAL LONG WAVE PATTERN THROUGH THE EXTENDED. A SHORT WAVE TROUGH WILL BE EXITING THE APPALACHIANS ON MONDAY...HELPING TO TEMPORARILY BUCKLE RIDGING ACROSS THE PLAINS AND INTO THE MISSISSIPPI VALLEY THROUGH TUESDAY. THE RIDGE WILL THEN BUILD BACK IN STRONGER ACROSS THE PLAINS...WITH A MORE VIGOROUS SHORT WAVE TROUGH TO MOVE THROUGH THE GREAT LAKES AND NEW ENGLAND FOR WEDNESDAY AND THURSDAY...SENDING A COLD FRONT SOUTH ACROSS THE OHIO VALLEY. THE MODELS HAVE COME ON BOARD A BIT MORE...WITH A MORE PROGRESSIVE SOLUTION FOR THESE FEATURES. FOR EASTERN KENTUCKY...THIS WILL KEEP THE THREAT OF SCATTERED...MAINLY DIURNALLY DRIVEN CONVECTION ACROSS MOST OF THE AREA THROUGH FRIDAY...BEFORE DEEPER MOISTURE SINKS FAR ENOUGH SOUTH ON SATURDAY...TO ONLY JUSTIFY A FEW POPS UP ALONG THE TN/VA BORDER. TEMPERATURES CONTINUE TO LOOK SLIGHTLY ABOVE NORMAL...WITH PERSISTENT HUMIDITY UNTIL NEXT WEEKEND. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING) ISSUED AT 815 PM EDT SAT JUL 14 2012 ANOTHER TRICKY AVN FORECAST WITH DIURNALLY DRIVEN CONVECTION DECREASING...BUT SOME DEBRIS CLOUDS AND STRATUS LINGER OUTSIDE OF CONVECTION. THERE IS ALSO SOME CHANCE IF A RENEWAL IN ACTIVITY TOWARDS DAWN AS A SHORTWAVE MOVES IN. AN INCREASE IS EXPECTED AGAIN ON SUN FROM AROUND 16Z ON WITH ANOTHER ROUND OF SCATTERED TO NUMEROUS STORMS. SC AND STRATUS NEAR SME AND LOZ BEHIND PRECIP OR IN VICINITY SHOULD AT LEAST TEMPORARILY DIMINISH WITH MORE IN THE WAY OF SOME MVFR OR IFR FOG DEVELOPING BY AROUND 3Z...AND VSBY DROPPING TOWARD LIFR OR EVEN VLIFR AT THE TAF SITES TOWARD DAWN. OUTSIDE OF CONVECTION...CONDITIONS SHOULD IMPROVE TO VFR BY AROUND 13Z. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JP SHORT TERM...GREIF LONG TERM....GEOGERIAN AVIATION...JP
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
816 PM EDT SAT JUL 14 2012 .UPDATE... ISSUED AT 815 PM EDT SAT JUL 14 2012 CONVECTION CONTINUES TO WEAKEN AS WE APPROACH SUNSET...AND OVERALL INTENSITIES HAVE DIMINISHED OVER THE PAST HOUR OR SO. MEASURABLE RAIN CHANCES WILL BE HIGHEST INITIALLY FROM NEAR JKL TOWARD THE BIG SANDY REGION AS THE REMAINING CONVECTION WORKS EAST NORTHEAST AND GRADUALLY IS EXPECTED TO CONTINUE TO WEAKEN OVER THE NEXT TWO HOURS. POPS AND SKY WERE UPDATED ACCORDINGLY BASED ON THESE TRENDS. && .SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT) ISSUED AT 335 PM EDT SAT JUL 14 2012 19Z SFC ANALYSIS SHOWS A WEAK PRESSURE PATTERN THROUGHOUT EAST KENTUCKY WITH NO CLEAR SYNOPTIC SCALE FEATURES TO KEY IN ON. HOWEVER...GIVEN THE HIGH PW AIR IN PLACE...NO CAP...AND SOME UPPER LEVEL ENERGY...NOT MUCH WAS NEEDED TO INITIATE THE STORMS LATE THIS MORNING THAT CONTINUE TO PERCOLATE OVER THE CWA AT THIS HOUR. THE CLOUDS FILLED IN FROM THE SOUTH BY MID MORNING AND CONVECTION FOLLOWED SHORTLY THEREAFTER. A FEW OF THE CELLS HAVE GOTTEN STRONG AND OTHERS HAVE MERGED/TRAINED OVER THE SAME SPOTS CREATING A CONCERN FOR MINOR URBAN OR SMALL STREAM FLOODING. REGARDLESS...THE RAINS IN MANY LOCATIONS ARE NOW PUTTING A SERIOUS DENT IN THEIR ANNUAL RAINFALL DEFICIT THANKS TO THESE PAST FEW DAYS. TEMPERATURES THIS AFTERNOON HAVE BEEN HIGHLY DEPENDENT ON THE CONVECTIVE PATTERN AND BREAKS FOR SUNSHINE WITH READINGS CURRENTLY RANGING FROM THE LOW 70S IN THE RAIN COOLED SOUTHERN I-75 CORRIDOR TO MID 80S JUST SOUTH OF STORMS NEAR I-64 AND IN THE...THUS FAR RAIN FREE...FAR SOUTHEAST. DEWPOINTS...MEANWHILE...REMAIN PEGGED IN THE LOW TO MID 70S SUPPLYING ALL THE JUICE THE CONVECTION COULD NEED. THE MODELS REMAIN IN AGREEMENT THAT EAST KENTUCKY WILL BE ON THE FRINGE OF THE WESTERN EXTENT OF A WEAK BERMUDA RIDGE AND AHEAD OF TROUGHING COMING FROM THE NORTHERN PLAINS AND CROSSING THE GREAT LAKES ON SUNDAY. THE ENERGY FROM THIS TROUGH WILL PASS BY TO THE NORTH LATER SUNDAY AND THIS WILL SERVE TO FURTHER LIMIT THE EFFECT OF THE EASTERN RIDGE ON OUR WEATHER INTO THE START OF THE NEW WORK WEEK. IN THIS ENVIRONMENT THE MESOSCALE...OR SMALLER...WILL DOMINATE SO HAVE LEANED MOST HEAVILY ON THE DETAILS OF THE NAM12 WITH A HEALTHY DOSE OF THE HRRR EARLY ON TONIGHT. SENSIBLE WEATHER WILL FEATURE SHOWERS AND THUNDERSTORMS WINDING DOWN...FOR THE MOST PART...AFTER SUNSET...BUT NOT BEFORE LEAVING BEHIND A FAIR AMOUNT OF RAINFALL IN SEVERAL LOCATIONS. EXPECT A LULL THROUGH THE MIDDLE OF THE NIGHT WITH PATCHY FOG A GOOD BET. THE APPROACH OF A SHORTWAVE INTO THE OHIO VALLEY LATE TONIGHT GIVES SOME CREDENCE TO THE NAM12/S IDEA OF A CONVECTIVE CLUSTER FORMING OVER CENTRAL TENNESSEE AND DRIFTING INTO THE CUMBERLAND VALLEY BY DAWN. SOME SUPPORT FROM THE GFS BOLSTERS THIS IDEA...AS WELL. ACCORDINGLY... HAVE DEVIATED FROM A STRICTLY DIURNALLY DRIVEN POP AND WX PATTERN TO ALLOW FOR THIS IDEA IN THE GRIDS...THOUGH NOT WHOLE HOG JUST YET. OTHERWISE...EXPECT A NEAR REPEAT OF TODAY FOR SUNDAY WITH CONVECTION DRIVEN MAINLY BY DIURNAL HEATING AND MINOR OUTFLOWS/DIFFERENTIAL HEATING BOUNDARIES. FOR BOTH TONIGHT AND SUNDAY NIGHT HAVE BEEN GENEROUS WITH THE PATCHY FOG IN THE GRIDS AFTER MIDNIGHT...BUT HELD OFF ON ANY DENSE UNTIL IT BECOMES MORE APPARENT WHERE THE BEST NOCTURNAL CLEARING WILL OCCUR. FOR TEMPERATURES...FOLLOWED A BLEND OF THE INHERITED GRIDS... PERSISTENCE...AND SOME OF THE LATEST MET VALUES...AGAIN NOT MUCH IN THE WAY OF TERRAIN EFFECTS FOR LOWS GIVEN THE HIGH DEWPOINTS. AS FOR POPS...HAVE ENDED UP SIMILAR TO A BLEND OF THE MET AND MAV MOS THROUGHOUT THE PERIOD. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 340 PM EDT SAT JUL 14 2012 THE MODELS REMAIN IN VERY GOOD AGREEMENT WITH THE GENERAL LONG WAVE PATTERN THROUGH THE EXTENDED. A SHORT WAVE TROUGH WILL BE EXITING THE APPALACHIANS ON MONDAY...HELPING TO TEMPORARILY BUCKLE RIDGING ACROSS THE PLAINS AND INTO THE MISSISSIPPI VALLEY THROUGH TUESDAY. THE RIDGE WILL THEN BUILD BACK IN STRONGER ACROSS THE PLAINS...WITH A MORE VIGOROUS SHORT WAVE TROUGH TO MOVE THROUGH THE GREAT LAKES AND NEW ENGLAND FOR WEDNESDAY AND THURSDAY...SENDING A COLD FRONT SOUTH ACROSS THE OHIO VALLEY. THE MODELS HAVE COME ON BOARD A BIT MORE...WITH A MORE PROGRESSIVE SOLUTION FOR THESE FEATURES. FOR EASTERN KENTUCKY...THIS WILL KEEP THE THREAT OF SCATTERED...MAINLY DIURNALLY DRIVEN CONVECTION ACROSS MOST OF THE AREA THROUGH FRIDAY...BEFORE DEEPER MOISTURE SINKS FAR ENOUGH SOUTH ON SATURDAY...TO ONLY JUSTIFY A FEW POPS UP ALONG THE TN/VA BORDER. TEMPERATURES CONTINUE TO LOOK SLIGHTLY ABOVE NORMAL...WITH PERSISTENT HUMIDITY UNTIL NEXT WEEKEND. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING) ISSUED AT 815 PM EDT SAT JUL 14 2012 ANOTHER TRICKY AVN FORECAST WITH DIURNALLY DRIVEN CONVECTION DECREASING...BUT SOME DEBRIS CLOUDS AND STRATUS LINGER OUTSIDE OF CONVECTION. THERE IS ALSO SOME CHANCE IF A RENEWAL IN ACTIVITY TOWARDS DAWN AS A SHORTWAVE MOVES IN. AN INCREASE IS EXPECTED AGAIN ON SUN FROM AROUND 16Z ON WITH ANOTHER ROUND OF SCATTERED TO NUMEROUS STORMS. SC AND STRATUS NEAR SME AND LOZ BEHIND PRECIP OR IN VICINITY SHOULD AT LEAST TEMPORARILY DIMINISH WITH MORE IN THE WAY OF SOME MVFR OR IFR FOG DEVELOPING BY AROUND 3Z...AND VSBY DROPPING TOWARD LIFR OR EVEN VLIFR AT THE TAF SITES TOWARD DAWN. OUTSIDE OF CONVECTION...CONDITIONS SHOULD IMPROVE TO VFR BY AROUND 13Z. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JP SHORT TERM...GREIF LONG TERM....GEOGERIAN AVIATION...JP
AREA FORECAST DISCUSSION
NWS JACKSON KY
126 AM EDT FRI JUL 13 2012 .UPDATE... ISSUED AT 122 AM EDT FRI JUL 13 2012 STEADY BUT MOSTLY LIGHT RAIN...IDEAL TO BREAK THE RECENT DROUGHT CONTINUES WITH RADAR STILL SHOWING MORE RAIN ADVANCING THROUGH MIDDLE TENN. UPDATED GRIDS TO REFLECT CURRENT VALUES BUT NO CHANGE NEEDED FOR ZONES. UPDATE ISSUED AT 1050 PM EDT THU JUL 12 2012 ISSUED AN UPDATE TO FRESHEN UP THE GRIDS. THE FORECAST IS IN GREAT SHAPE AND A NEW ZFP WILL NOT BE NEEDED. SENT THE GRIDS TO NDFD. UPDATE ISSUED AT 854 PM EDT THU JUL 12 2012 WITH THE BOUNDARY DOWN SOUTH SLOW TO GENERATE AND PUSH NORTH TO PROVIDE SOME INSTABILITY...HAVE ISSUED AN UPDATE. PULLED THUNDER OUT OF THE EARLY PART OF THE NIGHT TILL DAWN AS LIGHTNING STRIKES HAVE BEEN NONEXISTENT. LATER TONIGHT AS THE LOW CONTINUES TO DEVELOP...THE BOUNDARY WILL EVENTUALLY SLIDE NORTH BINGING SOME INSTABILITY INTO THE AREA. A NEW ZFP WAS ISSUED AND THE FORECAST IS GOOD TO GO. UPDATE ISSUED AT 557 PM EDT THU JUL 12 2012 ACROSS EASTERN KENTUCKY...A SHIELD OF SOAKING RAINFALL CONTINUES TO EDGE NORTH INTO THE FORECAST AREA WITH AN EMBEDDED RUMBLE OF THUNDER OR TWO. THE CONVECTION NORTH OF THE EDGE OF THE RAINFALL HAS SINCE DIED OFF AND SO WILL EXPECT FEW INSTANCES OF THUNDER THROUGH THE OVERNIGHT PERIOD. HAVE ADJUSTED THE TEMPERATURE TRENDS AND DEWS ACCORDING TO THE APPROACH OF THE RAINFALL. DECIDED NOT TO ISSUE A NEW ZFP AND SENT GRIDS TO NDFD...HOWEVER...IF STRIKES ACROSS THE AREA CONTINUE TO BE NIL INTO THE EVENING...MAY PULL THUNDER FOR THE NIGHT WITH THE NEXT ZFP ISSUANCE. && .SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT) ISSUED AT 340 PM EDT THU JUL 12 2012 18Z SFC ANALYSIS SHOWS HIGH PRESSURE TO THE NORTHEAST OF THE AREA WITH AN INVERTED TROUGH TAKING SHAPE THROUGH WESTERN TENNESSEE AND UP INTO CENTRAL KENTUCKY. AT THE NOSE OF THIS...A LARGE PCPN SHIELD IS STEADILY OVERTAKING MORE OF THE JKL CWA FROM SOUTHEAST TO NORTHWEST. THE THICK CLOUDS AND EARLY PCPN REALLY KEPT TEMPERATURES FROM CLIMBING TOO HIGH IN THE CUMBERLAND VALLEY AND AS SUCH THE STABILITY HAS TAKEN THE FORM OF MAINLY SHOWERS THERE. FURTHER TO THE NORTH AND WEST...THOUGH...MORE HEATING AND INSTABILITY HAS LED TO HEALTHIER CONVECTIVE CELLS AND EVEN THE ODD THUNDERSTORM. EXPECT THAT TO BE THE CASE THROUGH THE EVENING...THOUGH THE BULK OF THE PCPN WILL FALL AS SHOWERS. SPECIFICALLY...TEMPERATURE READINGS AT 2 PM EDT VARIED FROM THE LOWER 80S IN THE NORTHWEST WITH THE THINNER CLOUDS...TO LOWER 70S IN THE FAR SOUTHEAST IN THE SHOWERS. WINDS HAVE BEEN LIGHT THROUGH THE DAY AND GENERALLY FROM THE SOUTHEAST...WHICH HAS ALSO LIKELY HELPED TO GENERATE LOW LEVEL DOWNSLOPING WORKING AGAINST THE PCPN THROUGH THIS AFTERNOON. EVEN SO...WHERE THE CONVECTION HAS BEEN STRONGER IT ALSO HAS MOVED SLOWLY AND IS LEAVING BEHIND DECENT RAINFALL TOTALS OVER A SHORT AMOUNT OF TIME...GIVEN THE HIGH PW ENVIRONMENT. THE MODELS ARE IN PRETTY GOOD AGREEMENT WITH THE UPPER LEVEL PATTERN AND FEATURES TO AFFECT THE REGION THROUGH THE SHORT TERM. KENTUCKY AND THE MID MISSISSIPPI VALLEY WILL BE IN BETWEEN TWO RIDGES TO THE WEST AND EAST. THIS LOWER HEIGHT REGION IS POOLING WEAK PACKETS OF SHORTWAVE ENERGY WHILE THE NEAREST TROUGH STAYS OFF TO THE NORTH CLOSER TO GREAT LAKES AND NOT ABLE TO PUSH OUT THE LOST ENERGY... THROUGH SATURDAY MORNING. THE WEAKNESS ALOFT COMBINED WITH SOME ENERGY AND HIGH PWS OVER THE AREA WILL KEEP THE THREAT OF WIDESPREAD AND OCCASIONALLY HEAVY RAINS IN THE FORECAST FOR THE BULK OF THE PERIOD. WITH THE MODEL SIMILARITIES HAVE FOLLOWED A BLENDED APPROACH FAVORING THE NAM12 FOR MESOSCALE DETAILS. SENSIBLE WEATHER WILL FEATURE A MUCH NEEDED SOAKING RAIN EVENT THROUGH FRIDAY AS THE UPPER LEVEL FACTORS COMBINE WITH THE HIGH PWS AIR IN PLACE TO SUPPORT CONVECTION. SPECIFICALLY...EXPECT THE BEST CHANCE FOR HEAVY RAINS TO OCCUR LATER TONIGHT AND INTO THE FIRST PART OF FRIDAY PER THE EVOLUTION DEPICTED IN THE LATEST HRRR AND NAM12. THIS WILL GIVE A FAIRLY UNIFORM PATTERN OF HIGHER RAIN AMOUNTS...BUT THERE WILL STILL LIKELY BE CONSIDERABLE VARIABILITY WITH LOCALIZED HIGHER AMOUNTS GIVEN THE CONVECTIVE NATURE. WILL CONTINUE TO MENTION THE EXCESSIVE POTENTIAL IN THE HWO...BUT STILL LEAVE IT OUT FROM THE GRIDS AND ZONES. THE PCPN WILL START TO WANE LATER ON FRIDAY AS THE CORE OF IT SHIFTS NORTHWEST AND OUT OF THE BULK OF THE CWA. THERE WILL STILL BE A GOOD THREAT OF SHOWERS AND EVEN A THUNDERSTORM INTO SATURDAY MORNING BUT THE BEST RAINS WILL HAVE MOVED ON BY THEN. THIS RAIN IS QUITE BENEFICIAL AND WILL HOPEFULLY PUT A DECENT DENT IN OUR RAINFALL DEFICIT. AS FOR TEMPS... KEPT THEM FAIRLY UNIFORM SPATIALLY AND ELEVATIONALLY...WITH THE DIFFERENCES DRIVEN MORE BY THE RAIN PATTERN AND HIGH MOISTURE CONTENT OF THE AIR RATHER THAN ANY TERRAIN DIFFERENCES. FOLLOWED THE MET TEMPERATURES AND DEWPOINTS MOST CLOSELY FOR THE SHORT TERM AS THEY LOOKED REASONABLE FOR THE PCPN PATTERN AND MATCHED WELL WITH THE INHERITED GRIDS. AS FOR POPS...GENERALLY ENDED UP ON THE HIGH SIDE OF GUIDANCE...WHICH WAS ALSO FAIRLY SIMILAR THROUGH THE PERIOD. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 320 PM EDT THU JUL 12 2012 THE MODELS CONTINUE TO SHOW AN UNSETTLED PATTERN TO REMAIN ACROSS THE OHIO AND TENNESSEE VALLEYS THROUGH THE EXTENDED AS AN UPPER LEVEL RIDGE REMAINS NEARLY ANCHORED ACROSS BERMUDA...KEEPING A PERSISTENT FEED OF MOISTURE ACROSS EASTERN KENTUCKY...WHILE AT THE SAME TIME EXPOSING THE REGION TO PASSING WEAK DISTURBANCES IN THE FLOW AROUND THE RIDGE. GIVEN THE CONTINUED LOW CONFIDENCE IN TIMING ANYTHING THIS FAR OUT...WILL KEEP THE HIGHEST POPS CENTERED AROUND THE DIURNALLY FAVORED PERIODS. TOWARDS THE END OF THE WORK WEEK...A NORTHERN STREAM TROUGH WILL ATTEMPT TO BRING A COLD FRONT THROUGH THE AREA. WILL STICK WITH A SLOWER TIMING WITH THIS FEATURE. FOR TEMPERATURES...SLIGHTLY ABOVE NORMAL READINGS WILL REIGN...WITH HIGHS IN THE MID TO UPPER 80S...AND LOWS AROUND 70. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 130 AM EDT FRI JUL 13 2012 WITH DEVELOPING PRECIP SHIELD MOVING NORTH AND CONTINUING TO PROVIDE AMPLE COVERAGE OF SHOWER ACTIVITY...MVFR TO IFR CONDITIONS WILL PERSIST ACROSS THE AREA...INCLUDING THE TAF SITES...FOR MOST OF THE NEXT 24 HOUR TAF PERIOD. WITH SOME HEATING TOMORROW...MVFR TO IFR WILL PERSIST...BUT AS WARMER AIR TRACKS NORTH AND DAYTIME HEATING...ADDED VCTS TO THE TAF SITES. OTHERWISE...IFR UNTIL THIS AFTERNOON WHEN HEATING MAY BRING CONDITIONS TO VFR EVEN WITH OCCASIONAL TSRA UNTIL AFTER SUNSET AND THEN THE FOG...BR...RETURNS VSBY TO MVFR. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...DUSTY SHORT TERM...GREIF LONG TERM....GEOGERIAN AVIATION...DUSTY
AREA FORECAST DISCUSSION
NWS NEW ORLEANS LA
1147 PM CDT THU JUL 12 2012 .AVIATION... VFR CONDITIONS TO PREVAIL OUTSIDE CONVECTION...WHICH SHOULD ONLY DIP BRIEFLY TO MVFR CIGS/VSBY. CONVECTION MAY HAVE EARLIER INITIATION AS CONVERGENT BAND OFF THE COAST BECOMES MORE ACTIVE AND SPREADS INLAND IN THE MORNING ON OUTFLOW BOUNDARIES AND SEA BREEZE. GUST POTENTIAL CAN BE NEAR 40 KT WITH EARLY CONVECTION BUT SETTLE TO 25 KT IN LATE MORNING/AFTERNOON AS COVERAGE INCREASES. 24/RR && .PREV DISCUSSION... /ISSUED 827 PM CDT THU JUL 12 2012/ UPDATE... ..SOUNDING DISCUSSION... NO PROBLEMS WITH THE FLIGHT THIS EVENING. THE SOUNDING SHOWS A BIT OF A SURFACE INVERSION IN PLACE ON THE NORTHSHORE WHICH HAS HELPED TO QUIET THE SHOWER AND THUNDERSTORM ACTIVITY. ON THE SOUTHSHORE... A FEW STORMS ARE CONTINUING TO FIRE IN THE METRO NEW ORLEANS AREA. A STEADY STREAM OF MOISTURE IS WORKING INTO LOWER LEVELS FROM THE SOUTHWEST TO THE NORTHEAST ACROSS THE AREA SO ADDITIONAL DEVELOPMENT IS POSSIBLE AS HINTED TO BY THE HRRR MODELING. THAT SAID...CONVECTION IS ALREADY WANING OVERALL AND THERE COULD BE ANOTHER LULL ACROSS THE ENTIRE AREA FOR SEVERAL HOURS BEFORE THINGS BEGIN TO DEVELOP AGAIN TOMORROW. WINDS ARE OF OUT THE SOUTHWEST AT THE SURFACE AND INTO MID LEVELS AND ARE LIGHT AND VARIABLE ALOFT. && .PRELIMINARY POINT TEMPS/POPS... MCB 69 90 71 91 / 30 60 30 60 BTR 72 91 72 91 / 30 60 30 60 ASD 72 90 72 90 / 30 50 30 50 MSY 74 90 75 90 / 30 50 30 50 GPT 73 90 73 89 / 30 50 30 50 PQL 71 92 71 90 / 30 50 30 50 && .LIX WATCHES/WARNINGS/ADVISORIES... LA...NONE. GM...NONE. MS...NONE. GM...NONE. && $$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1028 AM EDT FRI JUL 13 2012 .SYNOPSIS... A SERIES OF UPPER LEVEL DISTURBANCES ALONG WITH INCREASING HUMIDITY WILL BRING SHOWERS AND THUNDERSTORMS TO THE AREA THROUGH THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... WITH 1030AM UPDATE...STILL TRYING TO GET A HANDLE ON JUST HOW FAR NORTH PRECIPITATION WILL MAKE IT DURING THE DAY. SURFACE DEWPOINT DEPRESSION AT MORGANTOWN IS 6 DEGREES...WHILE IT IS 17 DEGREES AT PITTSBURGH. 12Z PIT SOUNDING STILL SHOWS A GOOD BIT OF DRY AIR IN THE SURFACE-850MB LAYER...AND EXPECT THAT IT COULD BE SEVERAL HOURS BEFORE AIR IN EASTERN OHIO...NORTHERN WV PANHANDLE...AND SOUTHWESTERN PENNSYLVANIA MOISTENS UP ENOUGH AT LOW LEVELS FOR PRECIPITATION TO START FALLING. HAVE ALSO LOWERED HIGH TEMPERATURES BY A FEW DEGREES IN LOCATIONS THAT HAVE CHANCE FOR PRECIPITATION TODAY. PREVIOUS DISCUSSION FOLLOWS. THE LATEST RAP MID-LEVEL ANALYSIS INDICATES A TROUGH AXIS CENTERED ACROSS THE MISSOURI VALLEY WITH THE UPPER OHIO VALLEY IN A SOUTHWESTERLY FLOW AHEAD OF THIS FEATURE. A DEVELOPING SHORT WAVE IS RIDING NORTHEASTWARD ALONG THE OHIO RIVER ON THE EASTERN PERIPHERY OF THE LONG WAVE TROUGH. THIS FEATURE IS PROVIDING FORCING FOR SHOWERS ACROSS MUCH OF WEST VIRGINIA. A TIGHT 500MB MOISTURE GRADIENT IS LOCATED ALONG THE MASON-DIXON LINE AND IS SLOWLY SLIDING NORTHWARD INTO SOUTHWESTERN PA. 1000-850MB LAYER REMAINS QUITE DRY WITH 10-15 DEGREE DEW POINT DEPRESSIONS ACROSS MUCH OF THE AREA. THE SHORT WAVE WILL SLIDE SLOWLY NORTHEASTWARD INTO NORTH-CENTRAL WV, EASTERN OHIO, AND SOUTHWESTERN PA TODAY. FORCING FROM THE WAVE WILL ALLOW FOR SHOWERS TO DEVELOP AND MOVE INTO AREAS SOUTH OF THE I-70 CORRIDOR LATE THIS MORNING INTO THE EARLY AFTERNOON. THERE IS SOME UNCERTAINTY WITH THIS FORECAST IN REGARDS TO HOW LONG IT WILL TAKE FOR 1000-850MB LAYER TO SATURATE. DEEPER MOISTURE SHOULD ADVECT INTO THE AREA BY EVENING. MID-LEVEL MOISTURE WILL CONTINUE TO FILTER ACROSS THE AREA THROUGHOUT THE DAY, KEEPING SKIES MOSTLY CLOUDY ACROSS THE AREA. TEMP FORECAST IS CHALLENGING TODAY AS NORTHWARD ENCROACHMENT OF LOW-LEVEL MOISTURE AND SHOWERS WILL BE LIMITING FACTORS SOUTH OF PITTSBURGH. MAV/ECS GUIDANCE IS IN THE MID 70S FOR AREAS SOUTH OF PITTSBURGH AND MET GUIDANCE IS IN THE MID 80S FOR HIGHS IN THE SAME AREAS. FORECAST TAKES COOLER POCKET OF 850MB TEMPS (AROUND 13-14C) INDICATED BY GFS/ECMWF INTO CONSIDERATION FOR AREAS SOUTH OF PITTSBURGH. HIGHS ARE FORECAST TO RANGE FROM THE MID 70S ACROSS NORTH-CENTRAL WV TO THE MID 80S ALONG THE I-80 CORRIDOR. && .SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/... THERE IS ECMWF/GFS AGREEMENT THAT THE SHORT WAVE WILL SHIFT NORTHEAST OF THE AREA OVERNIGHT. 305K ISENTROPIC ANALYSIS INDICATES THAT UPLIFT WILL CONTINUE BEHIND THIS FEATURE IN A MOIST SOUTHWESTERLY FLOW. THUS, CHANCE POPS CONTINUE ACROSS MOST OF THE AREA OVERNIGHT. CLOUD COVERAGE ALONG WITH WARM TD ADVECTION WILL LIMIT LOWS TONIGHT, RANGING FROM THE UPPER 60S ACROSS NORTH-CENTRAL WV TO THE LOWER 60S ACROSS THE I-80 CORRIDOR AND EASTERN RIDGES. OVER THE WEEKEND, AN UPPER LEVEL RIDGE AXIS WILL REMAIN IN PLACE ACROSS THE CAROLINAS WITH THE LONG WAVE TROUGH DE-AMPLIFYING AND SLIDING EASTWARD ACROSS THE GREAT LAKES. WITH THE UPPER OHIO VALLEY BETWEEN THESE TWO FEATURES, IT WILL REMAIN IN A MOIST, SOUTHWESTERLY MID-LEVEL FLOW SATURDAY AND SUNDAY. THUS, CHANCE POPS CONTINUE THROUGH THE WEEKEND, INCREASING TO LIKELY WITH MODERATE INSTABILITY RETURNING THUNDERSTORMS TO THE FORECAST BY THE AFTERNOON ON SATURDAY. THUNDERSTORMS REMAIN IN THE FORECAST THROUGH SUNDAY AS DEW POINTS WARM INTO THE LOWER 70S AND PWATS INCREASE TO AROUND 2 INCHES ACROSS THE MAJORITY OF THE AREA. IT IS POSSIBLE THAT A FEW OF THE STORMS MAYS BECOME STRONG WITH GUSTY WINDS AND HEAVY DOWNPOURS OVER THE WEEKEND. AT THIS TIME, WIND PROFILE (0-6KM BULK SHEAR 25KTS) APPEARS TO BE MARGINALLY TOO WEAK TO MENTION A SEVERE THREAT IN THE HWO AND THUS CONCUR WITH THE STORM PREDICTION CENTER`S GENERAL THUNDERSTORM OUTLOOK. HIGH TEMPERATURES WILL BE NEAR NORMAL SEASONAL VALUES OVER THE WEEKEND WITH LOWS AROUND 5 DEGREES ABOVE NORMAL. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... MAINTAINED A CHANCE OF SHOWERS AND THUNDERSTORMS THIS PERIOD WITH CONTINUED HIGHER HUMIDITY AND WARMER THAN NORMAL TEMPERATURES. BLEND OF RECENT NAEFS AND ECMWF MODEL OUTPUT CONTINUE TO SHOW WEAK SOUTH TO SOUTHWESTERLY WINDS AT LOW LEVELS ACROSS THE UPPER OHIO VALLEY. AT UPPER LEVELS, THE INITIAL WEAK SHORT-WAVE TROUGH NEAR THE GREAT LAKES MAY BE SHEARED AS SHORT-WAVE TROUGH MOVES TOWARD THE GREAT LAKES FROM CENTRAL CANADA. THIS SCENARIO COULD RESULT IN A SOUTHEASTWARD MOVING COLD FRONT THROUGH THE GREAT LAKES AND PERHAPS UPPER OHIO VALLEY, BUT LIKELY NOT BEFORE THURSDAY. SO EXPECT CONTINUED HUMID CONDITIONS ACROSS THE UPPER OHIO VALLEY THIS PERIOD, WHICH WILL PROMOTE A CONTINUING CHANCE OF SHOWERS AND THUNDERSTORMS. FORECASTED TEMPERATURES UP TO 7 DEGREES WARMER THAN NORMAL BASED ON HPC GUIDANCE WHICH IN GENERAL WAS A COUPLE DEGREES WARMER THAN GFS AND ECMWF MOS BUT CLOSE TO NAEFS MEDIAN VALUES. && .AVIATION /15Z FRIDAY THROUGH TUESDAY/... EAST COAST HIGH PRESSURE WILL PROVIDE GENERAL VFR CONDITIONS FOR TODAY INTO TONIGHT, ALTHOUGH SHOWERS AND ISOLATED THUNDERSTORMS CAN POTENTIALLY PROVIDE BRIEF RESTRICTIONS...ESPECIALLY IN THE SOUTHERN PORTS LATE THIS MORNING AND THIS AFTERNOON. OUTLOOK...FRIDAY NIGHT THROUGH TUESDAY... CONTINUED HUMID CONDITIONS WILL PROMOTE POSSIBLE RESTRICTIONS DUE TO PATCHY FOG AND HAZE EACH MORNING, AND SCATTERED THUNDERSTORMS AT ANY TIME. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
817 AM EDT FRI JUL 13 2012 .SYNOPSIS... A SERIES OF UPPER LEVEL DISTURBANCES ALONG WITH INCREASING HUMIDITY WILL BRING SHOWERS AND THUNDERSTORMS TO THE AREA THROUGH THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... MINOR CHANGES WERE MADE TO TEMPERATURES AND POPS BASED ON SURFACE OBSERVATIONS AND RECENT RADAR TREND. THE LATEST RAP MID-LEVEL ANALYSIS INDICATES A TROUGH AXIS CENTERED ACROSS THE MISSOURI VALLEY WITH THE UPPER OHIO VALLEY IN A SOUTHWESTERLY FLOW AHEAD OF THIS FEATURE. A DEVELOPING SHORT WAVE IS RIDING NORTHEASTWARD ALONG THE OHIO RIVER ON THE EASTERN PERIPHERY OF THE LONG WAVE TROUGH. THIS FEATURE IS PROVIDING FORCING FOR SHOWERS ACROSS MUCH OF WEST VIRGINIA. A TIGHT 500MB MOISTURE GRADIENT IS LOCATED ALONG THE MASON-DIXON LINE AND IS SLOWLY SLIDING NORTHWARD INTO SOUTHWESTERN PA. 1000-850MB LAYER REMAINS QUITE DRY WITH 10-15 DEGREE DEW POINT DEPRESSIONS ACROSS MUCH OF THE AREA. THE SHORT WAVE WILL SLIDE SLOWLY NORTHEASTWARD INTO NORTH-CENTRAL WV, EASTERN OHIO, AND SOUTHWESTERN PA TODAY. FORCING FROM THE WAVE WILL ALLOW FOR SHOWERS TO DEVELOP AND MOVE INTO AREAS SOUTH OF THE I-70 CORRIDOR LATE THIS MORNING INTO THE EARLY AFTERNOON. THERE IS SOME UNCERTAINTY WITH THIS FORECAST IN REGARDS TO HOW LONG IT WILL TAKE FOR 1000-850MB LAYER TO SATURATE. DEEPER MOISTURE SHOULD ADVECT INTO THE AREA BY EVENING. MID-LEVEL MOISTURE WILL CONTINUE TO FILTER ACROSS THE AREA THROUGHOUT THE DAY, KEEPING SKIES MOSTLY CLOUDY ACROSS THE AREA. TEMP FORECAST IS CHALLENGING TODAY AS NORTHWARD ENCROACHMENT OF LOW-LEVEL MOISTURE AND SHOWERS WILL BE LIMITING FACTORS SOUTH OF PITTSBURGH. MAV/ECS GUIDANCE IS IN THE MID 70S FOR AREAS SOUTH OF PITTSBURGH AND MET GUIDANCE IS IN THE MID 80S FOR HIGHS IN THE SAME AREAS. FORECAST TAKES COOLER POCKET OF 850MB TEMPS (AROUND 13-14C) INDICATED BY GFS/ECMWF INTO CONSIDERATION FOR AREAS SOUTH OF PITTSBURGH. HIGHS ARE FORECAST TO RANGE FROM THE MID 70S ACROSS NORTH-CENTRAL WV TO THE MID 80S ALONG THE I-80 CORRIDOR. && .SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/... THERE IS ECMWF/GFS AGREEMENT THAT THE SHORT WAVE WILL SHIFT NORTHEAST OF THE AREA OVERNIGHT. 305K ISENTROPIC ANALYSIS INDICATES THAT UPLIFT WILL CONTINUE BEHIND THIS FEATURE IN A MOIST SOUTHWESTERLY FLOW. THUS, CHANCE POPS CONTINUE ACROSS MOST OF THE AREA OVERNIGHT. CLOUD COVERAGE ALONG WITH WARM TD ADVECTION WILL LIMIT LOWS TONIGHT, RANGING FROM THE UPPER 60S ACROSS NORTH-CENTRAL WV TO THE LOWER 60S ACROSS THE I-80 CORRIDOR AND EASTERN RIDGES. OVER THE WEEKEND, AN UPPER LEVEL RIDGE AXIS WILL REMAIN IN PLACE ACROSS THE CAROLINAS WITH THE LONG WAVE TROUGH DE-AMPLIFYING AND SLIDING EASTWARD ACROSS THE GREAT LAKES. WITH THE UPPER OHIO VALLEY BETWEEN THESE TWO FEATURES, IT WILL REMAIN IN A MOIST, SOUTHWESTERLY MID-LEVEL FLOW SATURDAY AND SUNDAY. THUS, CHANCE POPS CONTINUE THROUGH THE WEEKEND, INCREASING TO LIKELY WITH MODERATE INSTABILITY RETURNING THUNDERSTORMS TO THE FORECAST BY THE AFTERNOON ON SATURDAY. THUNDERSTORMS REMAIN IN THE FORECAST THROUGH SUNDAY AS DEW POINTS WARM INTO THE LOWER 70S AND PWATS INCREASE TO AROUND 2 INCHES ACROSS THE MAJORITY OF THE AREA. IT IS POSSIBLE THAT A FEW OF THE STORMS MAYS BECOME STRONG WITH GUSTY WINDS AND HEAVY DOWNPOURS OVER THE WEEKEND. AT THIS TIME, WIND PROFILE (0-6KM BULK SHEAR 25KTS) APPEARS TO BE MARGINALLY TOO WEAK TO MENTION A SEVERE THREAT IN THE HWO AND THUS CONCUR WITH THE STORM PREDICTION CENTER`S GENERAL THUNDERSTORM OUTLOOK. HIGH TEMPERATURES WILL BE NEAR NORMAL SEASONAL VALUES OVER THE WEEKEND WITH LOWS AROUND 5 DEGREES ABOVE NORMAL. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... MAINTAINED A CHANCE OF SHOWERS AND THUNDERSTORMS THIS PERIOD WITH CONTINUED HIGHER HUMIDITY AND WARMER THAN NORMAL TEMPERATURES. BLEND OF RECENT NAEFS AND ECMWF MODEL OUTPUT CONTINUE TO SHOW WEAK SOUTH TO SOUTHWESTERLY WINDS AT LOW LEVELS ACROSS THE UPPER OHIO VALLEY. AT UPPER LEVELS, THE INITIAL WEAK SHORT-WAVE TROUGH NEAR THE GREAT LAKES MAY BE SHEARED AS SHORT-WAVE TROUGH MOVES TOWARD THE GREAT LAKES FROM CENTRAL CANADA. THIS SCENARIO COULD RESULT IN A SOUTHEASTWARD MOVING COLD FRONT THROUGH THE GREAT LAKES AND PERHAPS UPPER OHIO VALLEY, BUT LIKELY NOT BEFORE THURSDAY. SO EXPECT CONTINUED HUMID CONDITIONS ACROSS THE UPPER OHIO VALLEY THIS PERIOD, WHICH WILL PROMOTE A CONTINUING CHANCE OF SHOWERS AND THUNDERSTORMS. FORECASTED TEMPERATURES UP TO 7 DEGREES WARMER THAN NORMAL BASED ON HPC GUIDANCE WHICH IN GENERAL WAS A COUPLE DEGREES WARMER THAN GFS AND ECMWF MOS BUT CLOSE TO NAEFS MEDIAN VALUES. && .AVIATION /12Z FRIDAY THROUGH TUESDAY/... EAST COAST HIGH PRESSURE WILL PROVIDE GENERAL VFR CONDITIONS FOR TODAY INTO TONIGHT, ALTHOUGH SHOWERS AND ISOLATED THUNDERSTORMS CAN POTENTIALLY PROVIDE BRIEF RESTRICTIONS...ESPECIALLY IN THE SOUTHERN PORTS LATE THIS MORNING AND THIS AFTERNOON. OUTLOOK...FRIDAY NIGHT THROUGH TUESDAY... CONTINUED HUMID CONDITIONS WILL PROMOTE POSSIBLE RESTRICTIONS DUE TO PATCHY FOG AND HAZE EACH MORNING, AND SCATTERED THUNDERSTORMS AT ANY TIME. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
422 AM EDT FRI JUL 13 2012 .SYNOPSIS... A SERIES OF UPPER LEVEL DISTURBANCES ALONG WITH INCREASING HUMIDITY WILL BRING SHOWERS AND THUNDERSTORMS TO THE AREA THROUGH THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... THE LATEST RAP MID-LEVEL ANALYSIS INDICATES A TROUGH AXIS CENTERED ACROSS THE MISSOURI VALLEY WITH THE UPPER OHIO VALLEY IN A SOUTHWESTERLY FLOW AHEAD OF THIS FEATURE. A DEVELOPING SHORT WAVE IS RIDING NORTHEASTWARD ALONG THE OHIO RIVER ON THE EASTERN PERIPHERY OF THE LONG WAVE TROUGH. THIS FEATURE IS PROVIDING FORCING FOR SHOWERS ACROSS MUCH OF WEST VIRGINIA. A TIGHT 500MB MOISTURE GRADIENT IS LOCATED ALONG THE MASON-DIXON LINE AND IS SLOWLY SLIDING NORTHWARD INTO SOUTHWESTERN PA. 1000-850MB LAYER REMAINS QUITE DRY WITH 10-15 DEGREE DEW POINT DEPRESSIONS ACROSS MUCH OF THE AREA. THE SHORT WAVE WILL SLIDE SLOWLY NORTHEASTWARD INTO NORTH-CENTRAL WV, EASTERN OHIO, AND SOUTHWESTERN PA TODAY. FORCING FROM THE WAVE WILL ALLOW FOR SHOWERS TO DEVELOP AND MOVE INTO AREAS SOUTH OF THE I-70 CORRIDOR LATE THIS MORNING INTO THE EARLY AFTERNOON. THERE IS SOME UNCERTAINTY WITH THIS FORECAST IN REGARDS TO HOW LONG IT WILL TAKE FOR 1000-850MB LAYER TO SATURATE. DEEPER MOISTURE SHOULD ADVECT INTO THE AREA BY EVENING. MID-LEVEL MOISTURE WILL CONTINUE TO FILTER ACROSS THE AREA THROUGHOUT THE DAY, KEEPING SKIES MOSTLY CLOUDY ACROSS THE AREA. THIS WILL LIMIT HEATING AND INSTABILITY, THUS ONLY HAVE A SCHC THUNDER LIMITED TO THE I-80 CORRIDOR WITH JUST SHOWERS ELSEWHERE. TEMP FORECAST IS CHALLENGING TODAY AS NORTHWARD ENCROACHMENT OF LOW-LEVEL MOISTURE AND SHOWERS WILL BE LIMITING FACTORS SOUTH OF PITTSBURGH. MAV/ECS GUIDANCE IS IN THE MID 70S FOR AREAS SOUTH OF PITTSBURGH AND MET GUIDANCE IS IN THE MID 80S FOR HIGHS IN THE SAME AREAS. FORECAST TAKES COOLER POCKET OF 850MB TEMPS (AROUND 13-14C) INDICATED BY GFS/ECMWF INTO CONSIDERATION FOR AREAS SOUTH OF PITTSBURGH. HIGHS ARE FORECAST TO RANGE FROM THE MID 70S ACROSS NORTH-CENTRAL WV TO THE MID 80S ALONG THE I-80 CORRIDOR. && .SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/... THERE IS ECMWF/GFS AGREEMENT THAT THE SHORT WAVE WILL SHIFT NORTHEAST OF THE AREA OVERNIGHT. 305K ISENTROPIC ANALYSIS INDICATES THAT UPLIFT WILL CONTINUE BEHIND THIS FEATURE IN A MOIST SOUTHWESTERLY FLOW. THUS, CHANCE POPS CONTINUE ACROSS MOST OF THE AREA OVERNIGHT. CLOUD COVERAGE ALONG WITH WARM TD ADVECTION WILL LIMIT LOWS TONIGHT, RANGING FROM THE UPPER 60S ACROSS NORTH-CENTRAL WV TO THE LOWER 60S ACROSS THE I-80 CORRIDOR AND EASTERN RIDGES. OVER THE WEEKEND, AN UPPER LEVEL RIDGE AXIS WILL REMAIN IN PLACE ACROSS THE CAROLINAS WITH THE LONG WAVE TROUGH DE-AMPLIFYING AND SLIDING EASTWARD ACROSS THE GREAT LAKES. WITH THE UPPER OHIO VALLEY BETWEEN THESE TWO FEATURES, IT WILL REMAIN IN A MOIST, SOUTHWESTERLY MID-LEVEL FLOW SATURDAY AND SUNDAY. THUS, CHANCE POPS CONTINUE THROUGH THE WEEKEND, INCREASING TO LIKELY WITH MODERATE INSTABILITY RETURNING THUNDERSTORMS TO THE FORECAST BY THE AFTERNOON ON SATURDAY. THUNDERSTORMS REMAIN IN THE FORECAST THROUGH SUNDAY AS DEW POINTS WARM INTO THE LOWER 70S AND PWATS INCREASE TO AROUND 2 INCHES ACROSS THE MAJORITY OF THE AREA. IT IS POSSIBLE THAT A FEW OF THE STORMS MAYS BECOME STRONG WITH GUSTY WINDS AND HEAVY DOWNPOURS OVER THE WEEKEND. AT THIS TIME, WIND PROFILE (0-6KM BULK SHEAR 25KTS) APPEARS TO BE MARGINALLY TOO WEAK TO MENTION A SEVERE THREAT IN THE HWO AND THUS CONCUR WITH THE STORM PREDICTION CENTER`S GENERAL THUNDERSTORM OUTLOOK. HIGH TEMPERATURES WILL BE NEAR NORMAL SEASONAL VALUES OVER THE WEEKEND WITH LOWS AROUND 5 DEGREES ABOVE NORMAL. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... MAINTAINED A CHANCE OF SHOWERS AND THUNDERSTORMS THIS PERIOD WITH CONTINUED HIGHER HUMIDITY AND WARMER THAN NORMAL TEMPERATURES. BLEND OF RECENT NAEFS AND ECMWF MODEL OUTPUT CONTINUE TO SHOW WEAK SOUTH TO SOUTHWESTERLY WINDS AT LOW LEVELS ACROSS THE UPPER OHIO VALLEY. AT UPPER LEVELS, THE INITIAL WEAK SHORT-WAVE TROUGH NEAR THE GREAT LAKES MAY BE SHEARED AS SHORT-WAVE TROUGH MOVES TOWARD THE GREAT LAKES FROM CENTRAL CANADA. THIS SCENARIO COULD RESULT IN A SOUTHEASTWARD MOVING COLD FRONT THROUGH THE GREAT LAKES AND PERHAPS UPPER OHIO VALLEY, BUT LIKELY NOT BEFORE THURSDAY. SO EXPECT CONTINUED HUMID CONDITIONS ACROSS THE UPPER OHIO VALLEY THIS PERIOD, WHICH WILL PROMOTE A CONTINUING CHANCE OF SHOWERS AND THUNDERSTORMS. FORECASTED TEMPERATURES UP TO 7 DEGREES WARMER THAN NORMAL BASED ON HPC GUIDANCE WHICH IN GENERAL WAS A COUPLE DEGREES WARMER THAN GFS AND ECMWF MOS BUT CLOSE TO NAEFS MEDIAN VALUES. && .AVIATION /08Z FRIDAY THROUGH TUESDAY/... EAST COAST HIGH PRESSURE WILL PROVIDE GENERAL VFR CONDITIONS FOR TODAY INTO TONIGHT, ALTHOUGH SHOWERS AND ISOLATED THUNDERSTORMS CAN POTENTIALLY PROVIDE BRIEF RESTRICTIONS...ESPECIALLY IN THE SOUTHERN PORTS LATE THIS MORNING AND THIS AFTERNOON. OUTLOOK...FRIDAY NIGHT THROUGH TUESDAY... CONTINUED HUMID CONDITIONS WILL PROMOTE POSSIBLE RESTRICTIONS DUE TO PATCHY FOG AND HAZE EACH MORNING, AND SCATTERED THUNDERSTORMS AT ANY TIME. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
218 AM EDT FRI JUL 13 2012 .SYNOPSIS... A SERIES OF UPPER LEVEL DISTURBANCES ALONG WITH INCREASING HUMIDITY WILL BRING SHOWERS AND THUNDERSTORMS TO THE AREA THROUGH THE WEEKEND. && .NEAR TERM /THROUGH TODAY/... 06Z ENHANCED SHORT TERM FORECAST UPDATE HAS BEEN ISSUED TO INCREASE POPS SOUTH OF PITTSBURGH THIS AFTERNOON AND TO ACCOUNT FOR THE LATEST TRENDS IN TEMP. THE LATEST RAP MID-LEVEL ANALYSIS INDICATES A TROUGH AXIS CENTERED ACROSS THE MISSOURI VALLEY WITH THE UPPER OHIO VALLEY IN A SOUTHWESTERLY FLOW AHEAD OF THIS FEATURE. A DEVELOPING SHORT WAVE IS RIDING NORTHEASTWARD ALONG THE OHIO RIVER ON THE EASTERN PERIPHERY OF THE LONG WAVE TROUGH. THIS FEATURE IS PROVIDING FORCING FOR SHOWERS ACROSS MUCH OF SOUTHERN WEST VIRGINIA. A TIGHT 500MB MOISTURE GRADIENT IS LOCATED ACROSS NORTH-CENTRAL WV AND IS SLOWLY SLIDING NORTHWARD INTO THE AREA. 1000-850MB LAYER REMAINS QUITE DRY WITH 10-15 DEGREE DEW POINT DEPRESSIONS ACROSS MUCH OF THE AREA. THE SHORT WAVE WILL SLIDE SLOWLY NORTHEASTWARD INTO NORTH-CENTRAL WV, EASTERN OHIO, AND SOUTHWESTERN PA TODAY. FORCING FROM THE WAVE WILL ALLOW FOR SHOWERS TO DEVELOP AND MOVE INTO AREAS SOUTH OF THE I-70 CORRIDOR LATE THIS MORNING INTO THE EARLY AFTERNOON. THERE IS SOME UNCERTAINTY WITH THIS FORECAST IN REGARDS TO HOW LONG IT WILL TAKE FOR 1000-850MB LAYER TO SATURATE. DEEPER MOISTURE SHOULD ADVECT INTO THE AREA BY EVENING. MID-LEVEL MOISTURE WILL CONTINUE TO FILTER ACROSS THE AREA THROUGHOUT THE DAY, KEEPING SKIES MOSTLY CLOUDY ACROSS THE AREA. THIS WILL LIMIT HEATING AND INSTABILITY, THUS ONLY HAVE A SCHC THUNDER MENTION FOR MOST OF THE AREA AND JUST SHOWERS ACROSS THE SOUTHEASTERN RIDGES. TEMP FORECAST IS CHALLENGING TODAY AS NORTHWARD ENCROACHMENT OF LOW-LEVEL MOISTURE AND SHOWERS COULD KEEP TEMPS DOWN SOUTH OF PITTSBURGH. MAV GUIDANCE IS IN THE MID 70S FOR AREAS SOUTH OF PITTSBURGH AND MET GUIDANCE IS IN THE MID 80S FOR HIGHS IN THE SAME AREAS. FORECAST TAKES COOLER POCKET OF 850MB TEMPS (AROUND 13-14C) INTO CONSIDERATION AND IS CLOSER TO THE COOLER MAV GUIDANCE FOR AREAS SOUTH OF PITTSBURGH. HIGHS ARE FORECAST TO RANGE FROM THE MID 70S ACROSS NORTH-CENTRAL WV TO THE MID 80S ALONG THE I-80 CORRIDOR. && .SHORT TERM /TONIGHT THROUGH SUNDAY/... BLEND OF RECENT SREF MODEL OUTPUT, COUPLED WITH DETAILS FROM RECENT NAM MODEL OUTPUT, SHOW THUNDERSTORM CHANCES ACROSS THE UPPER OHIO VALLEY INCREASING THIS PERIOD. THIS IS DUE TO A COUPLE FACTORS. THE FIRST FACTOR IS INCREASING SURFACE LAYER HUMIDITY THAT WILL PROMOTE INCREASED VERTICAL INSTABILITY. THE SECOND FACTOR IS A TREND TOWARD BETTER ORGANIZED LIFTING MECHANISMS. AT SOME POINT THERE WILL BE INCREASED MOISTURE CONVERGENCE ALONG THE LEADING EDGE OF THE HIGHER SURFACE DEW POINTS, A MESOSCALE FEATURE THAT COULD BE TERMED A DEW POINT WARM FRONT. THE SLOW EASTWARD PROGRESSION OF AN UPPER LEVEL SHORT- WAVE TROUGH NEAR THE GREAT LAKES, CAN PROVIDE ANOTHER SOURCE OF LIFT AND INSTABILITY WITH ITS PRECEDING DIFFLUENT FLOW AND SLIGHTLY COLDER TEMPERATURES ALOFT. DESPITE THE INCREASED THUNDERSTORM POTENTIAL, CONCUR WITH SPC REGARDING RESTRICTED SEVERE POTENTIAL DUE TO LACK OF VERTICAL WIND SHEAR. THERE CAN BE MORE OF A POTENTIAL FOR HEAVIER THUNDERSTORM RAINS DUE TO LARGER THAN NORMAL PRECIPITABLE WATER VALUES AND POTENTIAL FOR SLOW THUNDERSTORM MOVEMENT OR TRAINING. SOIL CONDITIONS ARE SUCH THAT MORE THAN 2 INCHES OF RAIN WOULD BE NEEDED IN 2 HOURS OR LESS TO CAUSE FLOODING ISSUES. FORECASTED WARMER THAN NORMAL TEMPERATURES THIS PERIOD, BUT WITH A SLIGHTLY SMALL DIURNAL TEMPERATURE RANGE DUE TO AN INCREASED CLOUD COVER, MORE HUMID SURFACE LAYER, AND THUNDERSTORM POTENTIAL. THIS IS SUPPORTED BY RECENT GFS AND NAM MOS, WHICH SHOWED MOST PERIODS WITH TEMPERATURES 2 TO 5 DEGREES WARMER THAN NORMAL. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... MAINTAINED A CHANCE OF SHOWERS AND THUNDERSTORMS THIS PERIOD WITH CONTINUED HIGHER HUMIDITY AND WARMER THAN NORMAL TEMPERATURES. BLEND OF RECENT NAEFS AND ECMWF MODEL OUTPUT CONTINUE TO SHOW WEAK SOUTH TO SOUTHWESTERLY WINDS AT LOW LEVELS ACROSS THE UPPER OHIO VALLEY. AT UPPER LEVELS, THE INITIAL WEAK SHORT-WAVE TROUGH NEAR THE GREAT LAKES MAY BE SHEARED AS SHORT-WAVE TROUGH MOVES TOWARD THE GREAT LAKES FROM CENTRAL CANADA. THIS SCENARIO COULD RESULT IN A SOUTHEASTWARD MOVING COLD FRONT THROUGH THE GREAT LAKES AND PERHAPS UPPER OHIO VALLEY, BUT LIKELY NOT BEFORE THURSDAY. SO EXPECT CONTINUED HUMID CONDITIONS ACROSS THE UPPER OHIO VALLEY THIS PERIOD, WHICH WILL PROMOTE A CONTINUING CHANCE OF SHOWERS AND THUNDERSTORMS. FORECASTED TEMPERATURES UP TO 7 DEGREES WARMER THAN NORMAL BASED ON HPC GUIDANCE WHICH IN GENERAL WAS A COUPLE DEGREES WARMER THAN GFS AND ECMWF MOS BUT CLOSE TO NAEFS MEDIAN VALUES. && .AVIATION /06Z FRIDAY THROUGH TUESDAY/... EAST COAST HIGH PRESSURE WILL PROVIDE GENERAL VFR CONDITIONS FOR TODAY INTO TONIGHT, ALTHOUGH SHOWERS AND ISOLATED THUNDERSTORMS CAN POTENTIALLY PROVIDE BRIEF RESTRICTIONS...ESPECIALLY IN THE SOUTHERN PORTS LATE THIS MORNING AND THIS AFTERNOON. OUTLOOK...FRIDAY NIGHT THROUGH TUESDAY... CONTINUED HUMID CONDITIONS WILL PROMOTE POSSIBLE RESTRICTIONS DUE TO PATCHY FOG AND HAZE EACH MORNING, AND SCATTERED THUNDERSTORMS AT ANY TIME. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
149 PM EDT FRI JUL 13 2012 .UPDATE... ISSUED AT 1206 PM EDT FRI JUL 13 2012 SKIES REMAIN FAIRLY CLEAR OVR MUCH OF THE AREA. MID CLOUDS TRIED TO MAKE PUSH INTO WESTERN CWA A FEW HOURS AGO BUT FELL APART RAPIDLY. WV LOOP AND RUC ANALYSIS INDICATES THAT THERE IS A DECENT AMOUNT OF DRY AIR OVR MUCH OF NORTHEAST AND NORTHERN WISCONSIN AND INTO WESTERN UPR MICHIGAN. 12Z GRB SOUNDING TURNED UP A K INDEX NEAR 30C BUT THE WV LOOP INDICATES THIS IS ONLY A VERY SMALL AREA OF HIGHER MOISTURE LIFTING TOWARD BAY OF GREEN BAY. DELAYED INCREASING CLOUD TREND IN THE WEST. EVENTUALLY COULD SEE AT LEAST ISOLD SHRA/TSRA FORM IN THE WEST AS WE PUSH PAST CONVECTIVE TEMPS IN THE MID 80S AND SOME WEAK FORCING AND MOISTURE ADVECTION EDGES ACROSS THAT AREA OUT AHEAD OF STRONGER DYNAMICS FM LARGER SCALE TROUGH FM NORTHWEST ONTARIO INTO NORTHERN MINNESOTA. SINCE H85 TEMPS HAVE ROSE ANOTHER 1-2C COMPARED TO YDY AND SKY COVER SHOULD BE MINIMAL FOR MUCH OF THE AREA...HAVE BUMPED UP FCST HIGHS THIS AFTN TO VALUES A COUPLE DEGREES HIGHER THAN THOSE OBSERVED YDY. MAIN RESULT WILL BE MANY AREAS PUSHING TOWARD OR JUST PAST THE 90 DEGREE MARK. EVEN SO...SINCE DWPNTS WILL CONTNIUE TO MIX OUT WITH THE DRIER AIR OVERHEAD WILL NOT BE AS HUMID AS IT COULD BE GIVEN THE WARMTH. THE DRIER AIR AND A BIT OF A SOUTH WIND WILL OVERALL MAKE FOR A COMFORTABLE 90 DEGREE DAY. FINALLY...LOOKING AHEAD FOR TONIGHT AND SATURDAY...CURRENT POPS/WX ARE GENERALLY ON TRACK. UPPER TROUGH AXIS IS FCST TO BE SQUARELY OVERHEAD UPR MICHIGAN BY SATURDAY AFTN...SO EXPECT HIGHER COVERAGE TO SHRA/TSRA BY THAT TIME AS HAS OCCURRED BENEATH THE UPR TROUGH AXIS THE LAST COUPLE DAYS. H85-H3 WINDS ARE WEAK BENEATH THE TROUGH AXIS AND GIVEN INCREASING PWATS TOWARD 150 PCT OF NORMAL...SEEMS LIKE MAIN ISSUE ON SATURDAY WILL BE HEAVY DOWNPOURS. ALREADY SEEING THIS AS KBDE IN FAR NORTHERN MN THIS MORNING /BENEATH THE TROUGH AXIS/ RECEIVED JUST UNDER 2 INCHES OF RAIN IN LESS THAN 2 HOURS WITH A SLOW MOVING THUNDERSTORM. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 456 AM EDT FRI JUL 13 2012 SHORT TERM PATTERN WILL BE DOMINATED BY A 500MB TROUGH CURRENTLY OVER SRN MANITOBA/ND/NW MN...THAT WILL LATER PHASE WITH AN UPPER LOW /AND ASSOCIATED TROUGH/ CURRENTLY OVER NRN ALBERTA. AT THE SFC...CURRENTLY THERE IS A TROUGH JUST E OF THE UPPER TROUGH AXIS INTO FAR WRN MN...AND HIGH PRESSURE OVER THE ERN SEABOARD. THIS PUTS IN THE CWA UNDER SW LOW LEVEL FLOW INITIALLY. SHOWERS FROM JUST W OF LAKE SUPERIOR STRETCHING ALONG THE WI/MN BORDER HAVE BEEN INCREASING IN COVERAGE EARLY TONIGHT...ALONG A RIBBON OF HIGHER MOISTURE IN THE WAA REGIME AHEAD OF THE SFC TROUGH. FOR TODAY...THE SRN UPPER TROUGH WILL PHASE WITH THE NRN UPPER LOW BY 00Z SAT...DEEPENING THE SRN EXTENT OF THE TROUGH THE AXIS MOVES TO JUST W OF LAKE SUPERIOR AND ALONG THE WI/MN BORDER...WITH THE SFC TROUGH ALMOST DIRECTLY BENEATH THE UPPER TROUGH. TRICKY TO SAY WHEN SHOWERS WILL GET INTO UPPER MI...AS THE RIBBON OF MOISTURE SLOWLY MOVES E. THE NAM IS ONE OF THE FASTER AND MORE AGRESSIVE MODELS WITH BRINGING THE MOISTURE INTO WRN UPPER MI THIS AFTERNOON...BUT OUTPUTS LITTLE QPF AS VER LOW LEVEL WILL BE DRY. PRIOR TO AROUND 21Z TODAY...IF ANY PRECIP MAKES IT TO THE GROUND IT SHOULD BE FAIRLY LIGHT. THINK BEST CHANCES FOR WRN UPPER MI TO SEE PRECIP TODAY WILL BE THIS EVENING WHILE WE STILL HAVE DECENT SFC HEATING AND A SHORTWAVE INDICATED BY MODELS MOVES IN FROM THE S. 850MB TEMPS OF UP TO 19C BY LATE IN THE DAY WILL SUPPORT HIGH TEMPS IN THE 80S TO AROUND 90...WARMEST CENTRAL AND E AWAY FROM LAKE MI. TONIGHT...THE SFC AND UPPER TROUGHS WILL MOVE INTO FAR WRN UPPER MI BY 12Z SAT. PRECIP WILL AGAIN BE TRICKY AS MODELS HAVE A HARD TIME TO DEALING WITH CONVECTIVE LEFTOVERS. ONE THING AGREED ON BY MODELS IS THAT ERN UPPER MI WILL BE DRIER THAN WRN UPPER MI...SINCE DRY LOW LEVEL AIR WILL LINGER OVER THE E THROUGH THE NIGHT. SEEMS THE BEST CHANCES FOR PRECIP WILL BE OVER WRN UPPER MI AND ALONG THE WI BORDER...WHERE I KEPT CHANCE AND SLIGHT CHANCE POPS...AND THE E SHOULD BE DRY. OVERALL CONFIDENCE IN OVERNIGHT PRECIP IS LOW. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 456 AM EDT FRI JUL 13 2012 MEDIUM RANGE GUIDANCE IS IN OVERALL DECENT AGREEMENT ON THE BIG PICTURE FOR NEXT WEEK AS IT PERTAINS TO UPPER MI. SLOW MOVING TROF PASSING ACROSS THE WRN GREAT LAKES THIS WEEKEND WILL BE FOLLOWED BY WEAK RIDGING EARLY NEXT WEEK AS WRN CONUS RIDGE EXPANDS EASTWARD. SHORTWAVE CRUISING ACROSS THE NRN CONUS/SRN CANADA WILL THEN TRANSLATE TO TROF AMPLIFICATION OVER SE CANADA/NE CONUS MIDWEEK. THEREAFTER...RIDGE WILL BUILD/EXPAND ACROSS THE CONUS WITH CENTER OF HOT RIDGE AGAIN SETTING UP OVER THE CNTRL STATES. END RESULT WILL BE ABOVE NORMAL TEMPS THRU EARLY NEXT WEEK...2 MAYBE 3 DAYS OF MORE PLEASANT SUMMER WEATHER MIDWEEK AS TROF AMPLIFIES TO THE E...AND THEN A RETURN TO POTENTIALLY WELL ABOVE NORMAL TEMPS LATE WEEK/NEXT WEEKEND AS HOT RIDGE EXPANDS OVER THE CNTRL CONUS. PATTERN DOES NOT LOOK TO FAVOR WELL ORGANIZED PCPN EVENTS. BEST SHOTS FOR PCPN WILL BE THIS WEEKEND WITH SLOW MOVING TROF AND POSSIBLY SOMETIME LATER MON/TUE AS COLD FRONT PASSES. DRY DAYS ARE A GOOD BET MIDWEEK AS SFC HIGH PRES SETTLES ACROSS THE UPPER LAKES...AND THEN RESURGENCE OF HEAT TOWARD THE UPPER LAKES LATE NEXT WEEK WILL PROBABLY SUPPORT SOME THREAT OF CONVECTION AT THAT TIME. AS ALLUDED TO ABOVE...TROF CURRENTLY OVER THE ERN DAKOTAS/WRN MN WILL SLOWLY MOVE ACROSS THE GREAT LAKES THIS WEEKEND. WITH TROF AXIS REACHING UPPER MI SAT AND COINCIDING WITH DAYTIME HEATING... SHRA/TSRA COVERAGE SHOULD BECOME NMRS. CNTRL UPPER MI MAY BE FAVORED FOR BEST COVERAGE GIVEN MORE IDEAL TIMING OF TROF WITH RESPECT TO DIURNAL CYCLE AND DUE TO SOME ASSISTANCE FROM LAKE BREEZES. DEEP LAYER SHEAR IS GENERALLY UNDER 20KT...SO ORGANIZED SVR STORMS ARE NOT EXPECTED. HOWEVER...IF THERE IS ENOUGH DAYTIME HEATING TO SIGNIFICANTLY BOOST INSTABILITY...THERE MAY BE ISOLD PULSE TYPE SVR STORMS SAT AFTN. RELATIVELY SLOW STORM MOVEMENT COULD LEAD TO SOME LOCALLY HVY RAINFALL. PCPN SHOULD GRADUALLY END FROM W TO E SAT NIGHT. SINCE MID LEVEL TROF AXIS WILL BE E OF THE FCST AREA BY SUN MORNING...IT APPEARS SUN WILL PROBABLY TURN OUT TO BE A DRY DAY. HOWEVER....RETAINED SLIGHT CHC POPS ACROSS THE SCNTRL/SE AS LAKE BREEZE INTERACTION MIGHT STILL YIELD ISOLD SHRA/TSRA. MIXING TO AROUND 800MB SUPPORTS MAX TEMPS UPWARDS OF AROUND 90F AWAY FROM MODEST LAKE BREEZE COOLING. SHORTWAVE WILL EJECT FROM TROF ALONG THE W COAST SUN NIGHT. IN RESPONSE TO THE WAVE TRACKING TOWARD SCNTRL CANADA...LOW-LEVEL JET WILL INCREASE ACROSS THE PLAINS. THIS SHOULD SUPPORT A CLUSTER OF SHRA/TSRA ON NOSE OF LOW-LEVEL JET AND ALONG EDGE OF CAP ACROSS ND/SRN SASKACHEWAN INTO NRN MN/SRN MANITOBA. AT THIS TIME... IT APPEARS LOW-LEVEL JET WILL STILL BE W OF THE AREA BY 12Z MON...SO DO NOT ANTICIPATE ANY CONVECTION LATE SUN NIGHT...EXCEPT POSSIBLY OVER WRN LAKE SUPERIOR. LOW-LEVEL JET SLIDES ACROSS THE AREA MON. THERE IS SOME UNCERTAINTY ON WHERE THE EDGE OF THE CAP WILL RESIDE...BUT GENERAL CONSENSUS IS THAT AT LEAST THE NRN/ERN PORTIONS OF THE FCST AREA WILL BE CLOSE ENOUGH TO WARRANT A MENTION OF SHRA/TSRA. WITH AREA ON THE CAPE GRADIENT AND UNDER 35-45KT OF DEEP LAYER SHEAR...ORGANIZED SVR STORMS WILL BE POSSIBLE IF THERE IS CONVECTION. IF THERE IS NO PCPN AND NOT MUCH CLOUD COVER...TEMPS UNDER WAA SHOULD EASILY RISE INTO THE LWR 90S IN MOST AREAS AWAY FROM LOCAL COOLING NEAR THE GREAT LAKES...MAINLY LAKE MI UNDER S TO SW BOUNDARY LAYER FLOW. COLD FRONT SLIDES ACROSS THE AREA MON NIGHT/TUE MORNING...PROVIDING A CHC OF SHRA/TSRA. WILL HANG ONTO CHC POPS THRU TUE AFTN GIVEN SOME UNCERTAINTY IN FRONTAL TIMING. OTHERWISE...COOLER/DRIER MORE COMFORTABLE AIR MASS WILL BEGIN SPREADING INTO THE AREA TUE. A MORE PLEASANT SUMMER DAY SHAPING UP FOR WED AS SFC HIGH PRES SETTLES OVER THE UPPER LAKES. HIGHS SHOULD BE IN THE LWR 70S ALONG LAKE SUPERIOR TO UPPER 70S/AROUND 80 INLAND WITH DWPTS FALLING THRU THE 50S. IT SHOULD REMAIN COMFORTABLE THU (DWPTS IN THE 50S)...THOUGH IT WILL BEGIN TO WARM UP JUST A LITTLE AS RETURN FLOW DEVELOPS ON BACKSIDE OF DEPARTING HIGH PRES. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON) ISSUED AT 147 PM EDT FRI JUL 13 2012 A COLD FRONT/UPPER LOW WILL APPROACH UPPER MICHIGAN LATE THIS AFTERNOON INTO THIS EVENING WHICH MAY TRIGGER WIDELY SCATTERED SHRA AND TSRA ACROSS FAR WESTERN UPPER MI INCLUDING IWD AND PERHAPS CMX. WITH LOSS OF DAYTIME HEATING/INSTABILITY...EXPECT GENERALLY QUIET CONDITIONS MOST OF TONIGHT. INCREASING SHRA/TSRA CHANCES ARE EXPECTED LATE TONIGHT THROUGH SATURDAY AS THE UPPER LOW MOVES OVERHEAD. BASED ON WHAT IS OCCURRING UPSTREAM IN MINNESOTA...BEST CHANCE OF TSRA WILL BE FM MID MORNING THROUGH THE AFTN HOURS ON SATURDAY. ALL TAF SITES COULD EXPERIENCE SCT SHRA/TSRA. APPEARS GREATEST CHANCE FOR TSRA WOULD BE LATE SATURDAY MORNING AT CMX AND INTO SATURDAY AFTN AT SAW. STORMS COULD DROP HEAVY RAIN WHICH COULD BRIEFLY RESULT IN IFR OR MVFR CONDITIONS IF A STORM DIRECTLY IMPACTS ONE OF THE TAF SITES. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 456 AM EDT FRI JUL 13 2012 A RIDGE OF HIGH PRESSURE CURRENTLY OVER THE REGION WILL SLOWLY GIVE WAY TO A WEAK TROUGH THAT WILL MOVE THROUGH OVER THE WEEKEND. OUT AHEAD OF THE TROUGH...S TO SE WINDS MAY REACH 20 KTS IN GUSTS OVR PORTIONS OF CNTRL AND EAST LAKE SUPERIOR TODAY INTO EARLY TONIGHT. OTHERWISE...WINDS WILL BE LESS THAN 20 KTS THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK IN WAKE OF THE TROUGH. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ UPDATE...JLA SHORT TERM...TITUS LONG TERM...ROLFSON AVIATION...JLA MARINE...TITUS
AREA FORECAST DISCUSSION...UPDATED
NWS MARQUETTE MI
1209 PM EDT FRI JUL 13 2012 .UPDATE... ISSUED AT 1206 PM EDT FRI JUL 13 2012 SKIES REMAIN FAIRLY CLEAR OVR MUCH OF THE AREA. MID CLOUDS TRIED TO MAKE PUSH INTO WESTERN CWA A FEW HOURS AGO BUT FELL APART RAPIDLY. WV LOOP AND RUC ANALYSIS INDICATES THAT THERE IS A DECENT AMOUNT OF DRY AIR OVR MUCH OF NORTHEAST AND NORTHERN WISCONSIN AND INTO WESTERN UPR MICHIGAN. 12Z GRB SOUNDING TURNED UP A K INDEX NEAR 30C BUT THE WV LOOP INDICATES THIS IS ONLY A VERY SMALL AREA OF HIGHER MOISTURE LIFTING TOWARD BAY OF GREEN BAY. DELAYED INCREASING CLOUD TREND IN THE WEST. EVENTUALLY COULD SEE AT LEAST ISOLD SHRA/TSRA FORM IN THE WEST AS WE PUSH PAST CONVECTIVE TEMPS IN THE MID 80S AND SOME WEAK FORCING AND MOISTURE ADVECTION EDGES ACROSS THAT AREA OUT AHEAD OF STRONGER DYNAMICS FM LARGER SCALE TROUGH FM NORTHWEST ONTARIO INTO NORTHERN MINNESOTA. SINCE H85 TEMPS HAVE ROSE ANOTHER 1-2C COMPARED TO YDY AND SKY COVER SHOULD BE MINIMAL FOR MUCH OF THE AREA...HAVE BUMPED UP FCST HIGHS THIS AFTN TO VALUES A COUPLE DEGREES HIGHER THAN THOSE OBSERVED YDY. MAIN RESULT WILL BE MANY AREAS PUSHING TOWARD OR JUST PAST THE 90 DEGREE MARK. EVEN SO...SINCE DWPNTS WILL CONTNIUE TO MIX OUT WITH THE DRIER AIR OVERHEAD WILL NOT BE AS HUMID AS IT COULD BE GIVEN THE WARMTH. THE DRIER AIR AND A BIT OF A SOUTH WIND WILL OVERALL MAKE FOR A COMFORTABLE 90 DEGREE DAY. FINALLY...LOOKING AHEAD FOR TONIGHT AND SATURDAY...CURRENT POPS/WX ARE GENERALLY ON TRACK. UPPER TROUGH AXIS IS FCST TO BE SQUARELY OVERHEAD UPR MICHIGAN BY SATURDAY AFTN...SO EXPECT HIGHER COVERAGE TO SHRA/TSRA BY THAT TIME AS HAS OCCURRED BENEATH THE UPR TROUGH AXIS THE LAST COUPLE DAYS. H85-H3 WINDS ARE WEAK BENEATH THE TROUGH AXIS AND GIVEN INCREASING PWATS TOWARD 150 PCT OF NORMAL...SEEMS LIKE MAIN ISSUE ON SATURDAY WILL BE HEAVY DOWNPOURS. ALREADY SEEING THIS AS KBDE IN FAR NORTHERN MN THIS MORNING /BENEATH THE TROUGH AXIS/ RECEIVED JUST UNDER 2 INCHES OF RAIN IN LESS THAN 2 HOURS WITH A SLOW MOVING THUNDERSTORM. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 456 AM EDT FRI JUL 13 2012 SHORT TERM PATTERN WILL BE DOMINATED BY A 500MB TROUGH CURRENTLY OVER SRN MANITOBA/ND/NW MN...THAT WILL LATER PHASE WITH AN UPPER LOW /AND ASSOCIATED TROUGH/ CURRENTLY OVER NRN ALBERTA. AT THE SFC...CURRENTLY THERE IS A TROUGH JUST E OF THE UPPER TROUGH AXIS INTO FAR WRN MN...AND HIGH PRESSURE OVER THE ERN SEABOARD. THIS PUTS IN THE CWA UNDER SW LOW LEVEL FLOW INITIALLY. SHOWERS FROM JUST W OF LAKE SUPERIOR STRETCHING ALONG THE WI/MN BORDER HAVE BEEN INCREASING IN COVERAGE EARLY TONIGHT...ALONG A RIBBON OF HIGHER MOISTURE IN THE WAA REGIME AHEAD OF THE SFC TROUGH. FOR TODAY...THE SRN UPPER TROUGH WILL PHASE WITH THE NRN UPPER LOW BY 00Z SAT...DEEPENING THE SRN EXTENT OF THE TROUGH THE AXIS MOVES TO JUST W OF LAKE SUPERIOR AND ALONG THE WI/MN BORDER...WITH THE SFC TROUGH ALMOST DIRECTLY BENEATH THE UPPER TROUGH. TRICKY TO SAY WHEN SHOWERS WILL GET INTO UPPER MI...AS THE RIBBON OF MOISTURE SLOWLY MOVES E. THE NAM IS ONE OF THE FASTER AND MORE AGRESSIVE MODELS WITH BRINGING THE MOISTURE INTO WRN UPPER MI THIS AFTERNOON...BUT OUTPUTS LITTLE QPF AS VER LOW LEVEL WILL BE DRY. PRIOR TO AROUND 21Z TODAY...IF ANY PRECIP MAKES IT TO THE GROUND IT SHOULD BE FAIRLY LIGHT. THINK BEST CHANCES FOR WRN UPPER MI TO SEE PRECIP TODAY WILL BE THIS EVENING WHILE WE STILL HAVE DECENT SFC HEATING AND A SHORTWAVE INDICATED BY MODELS MOVES IN FROM THE S. 850MB TEMPS OF UP TO 19C BY LATE IN THE DAY WILL SUPPORT HIGH TEMPS IN THE 80S TO AROUND 90...WARMEST CENTRAL AND E AWAY FROM LAKE MI. TONIGHT...THE SFC AND UPPER TROUGHS WILL MOVE INTO FAR WRN UPPER MI BY 12Z SAT. PRECIP WILL AGAIN BE TRICKY AS MODELS HAVE A HARD TIME TO DEALING WITH CONVECTIVE LEFTOVERS. ONE THING AGREED ON BY MODELS IS THAT ERN UPPER MI WILL BE DRIER THAN WRN UPPER MI...SINCE DRY LOW LEVEL AIR WILL LINGER OVER THE E THROUGH THE NIGHT. SEEMS THE BEST CHANCES FOR PRECIP WILL BE OVER WRN UPPER MI AND ALONG THE WI BORDER...WHERE I KEPT CHANCE AND SLIGHT CHANCE POPS...AND THE E SHOULD BE DRY. OVERALL CONFIDENCE IN OVERNIGHT PRECIP IS LOW. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 456 AM EDT FRI JUL 13 2012 MEDIUM RANGE GUIDANCE IS IN OVERALL DECENT AGREEMENT ON THE BIG PICTURE FOR NEXT WEEK AS IT PERTAINS TO UPPER MI. SLOW MOVING TROF PASSING ACROSS THE WRN GREAT LAKES THIS WEEKEND WILL BE FOLLOWED BY WEAK RIDGING EARLY NEXT WEEK AS WRN CONUS RIDGE EXPANDS EASTWARD. SHORTWAVE CRUISING ACROSS THE NRN CONUS/SRN CANADA WILL THEN TRANSLATE TO TROF AMPLIFICATION OVER SE CANADA/NE CONUS MIDWEEK. THEREAFTER...RIDGE WILL BUILD/EXPAND ACROSS THE CONUS WITH CENTER OF HOT RIDGE AGAIN SETTING UP OVER THE CNTRL STATES. END RESULT WILL BE ABOVE NORMAL TEMPS THRU EARLY NEXT WEEK...2 MAYBE 3 DAYS OF MORE PLEASANT SUMMER WEATHER MIDWEEK AS TROF AMPLIFIES TO THE E...AND THEN A RETURN TO POTENTIALLY WELL ABOVE NORMAL TEMPS LATE WEEK/NEXT WEEKEND AS HOT RIDGE EXPANDS OVER THE CNTRL CONUS. PATTERN DOES NOT LOOK TO FAVOR WELL ORGANIZED PCPN EVENTS. BEST SHOTS FOR PCPN WILL BE THIS WEEKEND WITH SLOW MOVING TROF AND POSSIBLY SOMETIME LATER MON/TUE AS COLD FRONT PASSES. DRY DAYS ARE A GOOD BET MIDWEEK AS SFC HIGH PRES SETTLES ACROSS THE UPPER LAKES...AND THEN RESURGENCE OF HEAT TOWARD THE UPPER LAKES LATE NEXT WEEK WILL PROBABLY SUPPORT SOME THREAT OF CONVECTION AT THAT TIME. AS ALLUDED TO ABOVE...TROF CURRENTLY OVER THE ERN DAKOTAS/WRN MN WILL SLOWLY MOVE ACROSS THE GREAT LAKES THIS WEEKEND. WITH TROF AXIS REACHING UPPER MI SAT AND COINCIDING WITH DAYTIME HEATING... SHRA/TSRA COVERAGE SHOULD BECOME NMRS. CNTRL UPPER MI MAY BE FAVORED FOR BEST COVERAGE GIVEN MORE IDEAL TIMING OF TROF WITH RESPECT TO DIURNAL CYCLE AND DUE TO SOME ASSISTANCE FROM LAKE BREEZES. DEEP LAYER SHEAR IS GENERALLY UNDER 20KT...SO ORGANIZED SVR STORMS ARE NOT EXPECTED. HOWEVER...IF THERE IS ENOUGH DAYTIME HEATING TO SIGNIFICANTLY BOOST INSTABILITY...THERE MAY BE ISOLD PULSE TYPE SVR STORMS SAT AFTN. RELATIVELY SLOW STORM MOVEMENT COULD LEAD TO SOME LOCALLY HVY RAINFALL. PCPN SHOULD GRADUALLY END FROM W TO E SAT NIGHT. SINCE MID LEVEL TROF AXIS WILL BE E OF THE FCST AREA BY SUN MORNING...IT APPEARS SUN WILL PROBABLY TURN OUT TO BE A DRY DAY. HOWEVER....RETAINED SLIGHT CHC POPS ACROSS THE SCNTRL/SE AS LAKE BREEZE INTERACTION MIGHT STILL YIELD ISOLD SHRA/TSRA. MIXING TO AROUND 800MB SUPPORTS MAX TEMPS UPWARDS OF AROUND 90F AWAY FROM MODEST LAKE BREEZE COOLING. SHORTWAVE WILL EJECT FROM TROF ALONG THE W COAST SUN NIGHT. IN RESPONSE TO THE WAVE TRACKING TOWARD SCNTRL CANADA...LOW-LEVEL JET WILL INCREASE ACROSS THE PLAINS. THIS SHOULD SUPPORT A CLUSTER OF SHRA/TSRA ON NOSE OF LOW-LEVEL JET AND ALONG EDGE OF CAP ACROSS ND/SRN SASKACHEWAN INTO NRN MN/SRN MANITOBA. AT THIS TIME... IT APPEARS LOW-LEVEL JET WILL STILL BE W OF THE AREA BY 12Z MON...SO DO NOT ANTICIPATE ANY CONVECTION LATE SUN NIGHT...EXCEPT POSSIBLY OVER WRN LAKE SUPERIOR. LOW-LEVEL JET SLIDES ACROSS THE AREA MON. THERE IS SOME UNCERTAINTY ON WHERE THE EDGE OF THE CAP WILL RESIDE...BUT GENERAL CONSENSUS IS THAT AT LEAST THE NRN/ERN PORTIONS OF THE FCST AREA WILL BE CLOSE ENOUGH TO WARRANT A MENTION OF SHRA/TSRA. WITH AREA ON THE CAPE GRADIENT AND UNDER 35-45KT OF DEEP LAYER SHEAR...ORGANIZED SVR STORMS WILL BE POSSIBLE IF THERE IS CONVECTION. IF THERE IS NO PCPN AND NOT MUCH CLOUD COVER...TEMPS UNDER WAA SHOULD EASILY RISE INTO THE LWR 90S IN MOST AREAS AWAY FROM LOCAL COOLING NEAR THE GREAT LAKES...MAINLY LAKE MI UNDER S TO SW BOUNDARY LAYER FLOW. COLD FRONT SLIDES ACROSS THE AREA MON NIGHT/TUE MORNING...PROVIDING A CHC OF SHRA/TSRA. WILL HANG ONTO CHC POPS THRU TUE AFTN GIVEN SOME UNCERTAINTY IN FRONTAL TIMING. OTHERWISE...COOLER/DRIER MORE COMFORTABLE AIR MASS WILL BEGIN SPREADING INTO THE AREA TUE. A MORE PLEASANT SUMMER DAY SHAPING UP FOR WED AS SFC HIGH PRES SETTLES OVER THE UPPER LAKES. HIGHS SHOULD BE IN THE LWR 70S ALONG LAKE SUPERIOR TO UPPER 70S/AROUND 80 INLAND WITH DWPTS FALLING THRU THE 50S. IT SHOULD REMAIN COMFORTABLE THU (DWPTS IN THE 50S)...THOUGH IT WILL BEGIN TO WARM UP JUST A LITTLE AS RETURN FLOW DEVELOPS ON BACKSIDE OF DEPARTING HIGH PRES. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING) ISSUED AT 729 AM EDT FRI JUL 13 2012 VFR CONDITIONS ARE GENERALLY EXPECTED ACROSS ALL SITES FOR THE NEXT 24 HOURS. A COLD FRONT/UPPER DISTURBANCE WILL APPROACH UPPER MICHIGAN LATE THIS AFTERNOON INTO THIS EVENING WHICH MAY TRIGGER WIDELY SCATTERED SHOWERS AND THUNDERSTORMS THIS AFTERNOON ACROSS FAR WESTERN UPPER MI INCLUDING IWD. THIS COULD ALLOW FOR BRIEF IFR CONDITIONS AT IWD AFT 22Z TODAY...BUT THERE IS NOT ENOUGH CONFIDENCE TO INCLUDE IN THE TERMINAL AT THIS TIME. CONFIDENCE ON PRECIP IS LOW...ESPECIALLY AT SAW AND CMX WHICH WILL BE MORE ON THE FRINGES OF WHERE THE BEST PRECIP CHANCES ARE. FOR CMX AND SAW...JUST PUT VCSH IN THE FORECAST AT THIS TIME GIVEN THE UNCERTAINTY. OTHERWISE...S-SW WINDS WILL GUST TO AROUND 20 KT AHEAD OF THE COLD FRONT ON FRIDAY. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 456 AM EDT FRI JUL 13 2012 A RIDGE OF HIGH PRESSURE CURRENTLY OVER THE REGION WILL SLOWLY GIVE WAY TO A WEAK TROUGH THAT WILL MOVE THROUGH OVER THE WEEKEND. OUT AHEAD OF THE TROUGH...S TO SE WINDS MAY REACH 20 KTS IN GUSTS OVR PORTIONS OF CNTRL AND EAST LAKE SUPERIOR TODAY INTO EARLY TONIGHT. OTHERWISE...WINDS WILL BE LESS THAN 20 KTS THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK IN WAKE OF THE TROUGH. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ UPDATE...JLA SHORT TERM...TITUS LONG TERM...ROLFSON AVIATION...TITUS MARINE...TITUS
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1200 PM EDT FRI JUL 13 2012 .SYNOPSIS... ISSUED AT 337 AM EDT FRI JUL 13 2012 IT WILL REMAIN SUMMERY TODAY AND THROUGH THE WEEKEND WITH DAYTIME TEMPERATURES REACHING AROUND 90 EACH DAY. WE WILL HAVE SCATTERED CHANCES FOR SHOWERS AND THUNDERSTORMS AS A WEAK FRONT AND UPPER LEVEL DISTURBANCE MOVES INTO THE REGION. ALTHOUGH THE PRECIPITATION IS EXPECTED TO REMAIN SCATTERED...THE BEST CHANCE FOR RAIN WILL COME SATURDAY INTO EARLY SATURDAY NIGHT. WE WILL SEE LITTLE CHANGE IN TEMPERATURES INTO NEXT WEEK...WITH ANOTHER CHANCE OF SCATTERED STORMS TUESDAY NIGHT. && .UPDATE... ISSUED AT 1159 AM EDT FRI JUL 13 2012 HAVE UPDATED TO EXPAND A SMALL CHANCE (20 POP/ISOLATED WORDING) ACROSS THE ENTIRE FORECAST AREA. COVERAGE IS OBVIOUSLY EXPECTED TO BE LOW...BUT THE 4KM NSSL WRF...4KM SPC WRF AND THE LATEST HRRR ARE ALL INDICATING ISOLATED DEVELOPMENT CWA WIDE THIS AFTERNOON. A WEAK LAKE BREEZE MAY END UP BEING A FOCUS. IN ADDITION...WATER VAPOR IMAGERY SEEMS TO INDICATE A WEAK SHORTWAVE MOVING THROUGH THE CWA AT THIS TIME NOTED BY A LITTLE BETTER MOISTURE IN AN OVERALL MINIMUM ACROSS THE SOUTHERN GREAT LAKES. MODIFYING AREA MORNING SOUNDINGS INDICATE THAT WE SHOULD BE ABLE TO REALIZE CAPE VALUES AROUND 1000 J/KG AND LI/S AROUND -3 TO -4C. THESE VALUES ARE WITH TEMPS AROUND 90 AND DEW POINTS IN THE UPPER 50S. THE THINKING IS WE WILL LIKELY MIX DOWN SLIGHTLY DRIER AIR. IF WE HANG ON TO THE LOW TO MID 60S DEW POINTS...THE INSTABILITY WILL OBVIOUSLY BE HIGHER. NOT EXPECTING ANYTHING SEVERE AS VERY LITTLE SHEAR EXISTS. THE NAM FOR INSTANCE HAS WINDS LESS THAN 15 KNOTS ALL THE WAY THROUGH ABOUT 18000FT. SO...PULSE STORMS ARE EXPECTED FIRING OFF LAKE BREEZE CONVERGENCE AND OUTFLOW BOUNDARIES. GIVEN THE WEAK SHEAR THE LIFE CYCLE OF STORMS TODAY WILL BE FAIRLY SHORT. LOCALLY HEAVY RAIN AND LIGHTNING WOULD BE THE MAIN THREATS. && .SHORT TERM...(TODAY THROUGH SUNDAY) ISSUED AT 337 AM EDT FRI JUL 13 2012 OVERALL THINKING HAS NOT CHANGED MUCH THROUGH THE SHORT TERM... ALTHOUGH SOME TWEAKS WERE MADE FOR SATURDAY NIGHT AND SUNDAY AS THE TIMING OF THE UPPER WAVE HAS CHANGED SOMEWHAT. MAIN NORTHERN STREAM SHORT WAVE WAS OVER THE DAKOTAS MOVING INTO WESTERN MN THIS MORNING. HOWEVER TROUGHING EXTENDED AS FAR EAST AS CHICAGO WHICH RESEMBLES A WARM FRONT ALOFT. THIS FEATURE MOVES NE FROM CHI TOWARD CENTRAL LOWER THROUGH THE DAY. THERE WAS AN EXPANDING AREA OF CLOUDS WITH THIS FEATURE AND ALSO A FEW SPOTTY RADAR RETURNS. SOUNDINGS ARE QUITE DRY IN THE LOW LEVELS...SO ANYTHING THAT TRIES TO GENERATE WILL BE HIGH BASED AND SHOULD ONLY PRODUCE THE CHANCE OF A BRIEF SHOWER. CAN NOT RULE OUT A LIGHTNING STRIKE TOO. SEEMS LIKE THIS WILL HEAD ACROSS THE NORTHERN CWA WHERE 20 POPS WILL BE CARRIED TODAY. SLIGHTLY BETTER CHANCES FOR RAIN SHOULD MOVE INTO THE AREA LATE TONIGHT...PEAKING SATURDAY INTO SATURDAY EVENING AS THE MAIN SHORT WAVE MAKES IT EAST INTO THE GREAT LAKES. STILL NOT OVERLY IMPRESSED BY THE LACK OF JET DYNAMICS AND THE SYSTEM IS NOT LOADED WITH MOISTURE EITHER. FEEL OUR 40 POPS COVER IT WELL FOR SATURDAY. HOWEVER WILL INCREASE THE FORECAST TO 40 POPS INTO SATURDAY EVENING AS THE SHORT WAVE SHOULD CROSS THE CWA IN THIS TIME FRAME. SEVERE POTENTIAL LOOKS VERY LOW GIVEN THE WEAK WIND FIELDS. MUCH OF THE ACTION APPEARS TO BE EAST OF THE AREA INTO SUNDAY...ALTHOUGH THE SE CWA MAY STILL SEE LINGERING SHOWERS/STORMS. THEREFORE...REMOVED POPS OVER THE NW AND LOWERED POPS OVER THE CENTRAL CWA AS THE UPPER SUPPORT MOVES SOUTH AND EAST. ALSO BUMPED UP MAX TEMPS SEVERAL DEGREES WITH MORE SUNSHINE EXPECTED. .LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY) ISSUED AT 337 AM EDT FRI JUL 13 2012 GIVEN THE PREVAILING AND TO SOME EXTENT EXPANDING DROUGHT OVER SOUTHWEST LOWER MICHIGAN... THE MAIN ISSUE IS CAN WE GET A SIGNIFICANT RAINFALL EVENT DURING THIS TIME? THE OTHER ISSUE IS THE TEMPERATURE...JUST HOW HOT DOES IT GET THIS COMING WEEK? THROUGH THURSDAY MORNING THE MODELS ARE LARGELY IN AGREEMENT AT THE JET STREAM LEVEL AS TO WHAT WILL HAPPEN. A SYSTEM NOW IN THE GULF OF ALASKA RACES ACROSS SOUTHERN CANADA AND PHASES WITH THE CLOSED UPPER LOW CURRENTLY OVER NW CANADA BUT BY THEN EAST OF HUDSON BAY. THIS CREATES AN UPPER LEVEL JET ASSIST FOR THE GULF OF ALASKA SYSTEM AS IT PHASES WITH THE CLOSED UPPER LOW. THAT IN TURN HELPS PUSH THE COLD FRONT SOUTH INTO THE SOUTHERN GREAT LAKES TUESDAY NIGHT INTO WEDNESDAY. IT IS AT THIS TIME WE STAND OUR BEST CHANCE OF SEEING SHOWERS AND THUNDERSTORMS ACROSS THE CWA. BEYOND THAT SOME ISSUES DEVELOP WITH THE NEXT PACIFIC SYSTEM LATE IN THE WEEK WHERE THE ECMWF IS STRONGER WITH THE SYSTEM THAT COMES ON SHORE IN THE PACIFIC NORTHWEST WHICH LEADS TO A LARGER UP-STREAM SUBTROPICAL HIGH. AS FOR OUR CONVECTION WITH THE COLD FRONT TUESDAY NIGHT... THAT BY ITSELF IS AN ISSUE. THE FRONT IS COMING THROUGH EARLY WEDNESDAY MORNING. NOT THE BEST TIME FOR CONVECTION IN THE FIRST PLACE. ON THE UP SIDE THE PRECIPITABLE WATER WILL BE OVER 2 INCHES (NEARLY DOUBLE NORMAL). ALSO THERE IS A TAIL OF UPPER LEVEL JET CORE CROSSING CENTRAL LOWER MICHIGAN TUESDAY NIGHT INTO WEDNESDAY MORNING THAT PUTS SOUTHWEST MICHIGAN IN THE RIGHT ENTRANCE REGION OF THE JET CORE (THAT WILL HELP WITH THE LIFT FOR CONVECTION). THERE IS CONVERGENCE ON THE SURFACE FRONT... ANOTHER GOOD THING. THE MOST UNSTABLE CAP IS BETWEEN 2000 AND 3000 J/KG EVEN AT NIGHT SO THAT IS A POSITIVE TOO. THE DEEP LAYER SHEAR IS NEAR 30 KNOTS DUE TO JET CORE MOVING THROUGH. SO IT WOULD SEEM WE DO HAVE A SHOT AT SOME CONVECTION WITH THE FRONT SO I HAVE BETWEEN 30 AND 40 PCT FOR NOW AND CALLED THAT GOOD. THE OVER RIDING STORY FOR THIS WEEK THROUGH IS THE POLAR JET STREAM STAYS WELL NORTH OF 55 NORTH THROUGH THIS COMING WEEK (BASED ON THE PV15 WIND MAX). THAT MEANS WHATEVER COLD PUSH WE GET WILL BE FEEBLE AT BEST AND SHORT LIVED. OVERALL OUR HOT WEATHER WILL LIKELY CONTINUE THROUGH THE WEEK WITH ONLY A MINOR COOL OFF (NOT EVEN TO NORMAL) WED/THU. GIVEN THE GFS MAX TEMP FOR THE 84 HOUR THROUGH 240 HOUR (8TH THROUGH THE 11TH) AS A MEAN AVERAGE ERROR OF OVER 8 DEGREES ON THE HIGH TEMPERATURE AND BIAS IS ABOUT THE SAME... WHILE THE ECMWF FOR THE TIME HAS A MEAN AVERAGE ERROR OF ONLY 4 DEGREES... I PUSHED THE HIGHS UP TO BE CLOSER TO THE ECMWF VALUES THROUGH THE WEEK. NOTE: CURIOUSLY THE ERROR FOR THE LOW TEMPS FAVORS THE GFS SO I DID NOT DO MUCH WITH THE LOWS. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING) ISSUED AT 650 AM EDT FRI JUL 13 2012 VFR CIGS/VSBY ARE EXPECTED THROUGH SATURDAY MORNING. THERE COULD BE A FEW THUNDERSTORMS AROUND MID AFTERNOON INTO THE EARLY EVENING SO I CONTINUED THE VCTS IN ALL THE INLAND TAF SITES TODAY. ANY STORM WILL BE SHORT LIVED BUT THERE COULD BE A BRIEF LOWERING OF THE VISIBILITY IN THE HEAVER SHOWERS. CLOUD BASES SHOULD STILL BE IN THE 6000 TO 7000 FT RANGE THIS MORNING AND MORE LIKE 8000 TO 9000 FT AGL THIS AFTERNOON (BASED ON 06Z NAM12 AND 09Z RAP SOUNDINGS). && .MARINE... ISSUED AT 337 AM EDT FRI JUL 13 2012 A LIGHT SOUTHERLY FLOW WILL CONTINUE THROUGH SATURDAY...THEN VEER TO THE WEST LATE SATURDAY NIGHT WITH THE FRONT COMING THROUGH. WAVE ACTION SHOULD REMAIN LOW. && .HYDROLOGY... ISSUED AT 337 AM EDT FRI JUL 13 2012 PCPN LATE TONIGHT INTO EARLY SUNDAY STILL LOOKS RATHER LIGHT...NOT THE DROUGHT BUSTER THAT WE NEED. CAN NOT RULE OUT LOCALIZED HEAVY RAINS...BUT MOST RIVER BASIN AVERAGES WILL BE UNDER A QUARTER INCH...HAVING VERY LITTLE HYDRO IMPACT. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. && $$ UPDATE...DUKE SYNOPSIS...JK SHORT TERM...JK LONG TERM...WDM AVIATION...WDM HYDROLOGY...JK MARINE...JK
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
651 AM EDT FRI JUL 13 2012 .SYNOPSIS... ISSUED AT 337 AM EDT FRI JUL 13 2012 IT WILL REMAIN SUMMERY TODAY AND THROUGH THE WEEKEND WITH DAYTIME TEMPERATURES REACHING AROUND 90 EACH DAY. WE WILL HAVE SCATTERED CHANCES FOR SHOWERS AND THUNDERSTORMS AS A WEAK FRONT AND UPPER LEVEL DISTURBANCE MOVES INTO THE REGION. ALTHOUGH THE PRECIPITATION IS EXPECTED TO REMAIN SCATTERED...THE BEST CHANCE FOR RAIN WILL COME SATURDAY INTO EARLY SATURDAY NIGHT. WE WILL SEE LITTLE CHANGE IN TEMPERATURES INTO NEXT WEEK...WITH ANOTHER CHANCE OF SCATTERED STORMS TUESDAY NIGHT. && .UPDATE... ISSUED AT 650 AM EDT FRI JUL 13 2012 BASED ON THE NSSL WAF (13TH 00Z) AND LOOKING AT SOUNDING FROM THE 09Z RAP AND 06Z NAM12 THE DEPTH OF THE MOISTURE IN THE SOUNDINGS INCREASE FROM 800 TO 600 MB AT 15Z TO 75O MB TO 550 MB BY 21Z. THIS SHOULD ALLOW SOME PARCELS TO GET A LITTLE MORE DEPTH BEFORE THE RUN IN THE VERY DRY AIR ABOVE 550 MB. WITH THE AID UPSTREAM SHORTWAVE SEEN NICELY ON OUR WATER VAPOR LOOPS...IN COMBINATION WITH THE LAKE BREEZE CONVERGENCE THERE SHOULD BE ENOUGH LOCALIZED LIFT TO ALLOW A FEW SHOWERS AND ISOLATED THUNDERSTORMS TO GET GOING. I EXPANDED THE AREA OF POTENTIAL SHOWERS TO COVER MORE OF THE CWA. EVEN SO THE CHANCE OF ANY ONE LOCATION GETTING THE SHOWERS WILL BE LIMITED AT BEST. && .SHORT TERM...(TODAY THROUGH SUNDAY) ISSUED AT 337 AM EDT FRI JUL 13 2012 OVERALL THINKING HAS NOT CHANGED MUCH THROUGH THE SHORT TERM... ALTHOUGH SOME TWEAKS WERE MADE FOR SATURDAY NIGHT AND SUNDAY AS THE TIMING OF THE UPPER WAVE HAS CHANGED SOMEWHAT. MAIN NORTHERN STREAM SHORT WAVE WAS OVER THE DAKOTAS MOVING INTO WESTERN MN THIS MORNING. HOWEVER TROUGHING EXTENDED AS FAR EAST AS CHICAGO WHICH RESEMBLES A WARM FRONT ALOFT. THIS FEATURE MOVES NE FROM CHI TOWARD CENTRAL LOWER THROUGH THE DAY. THERE WAS AN EXPANDING AREA OF CLOUDS WITH THIS FEATURE AND ALSO A FEW SPOTTY RADAR RETURNS. SOUNDINGS ARE QUITE DRY IN THE LOW LEVELS...SO ANYTHING THAT TRIES TO GENERATE WILL BE HIGH BASED AND SHOULD ONLY PRODUCE THE CHANCE OF A BRIEF SHOWER. CAN NOT RULE OUT A LIGHTNING STRIKE TOO. SEEMS LIKE THIS WILL HEAD ACROSS THE NORTHERN CWA WHERE 20 POPS WILL BE CARRIED TODAY. SLIGHTLY BETTER CHANCES FOR RAIN SHOULD MOVE INTO THE AREA LATE TONIGHT...PEAKING SATURDAY INTO SATURDAY EVENING AS THE MAIN SHORT WAVE MAKES IT EAST INTO THE GREAT LAKES. STILL NOT OVERLY IMPRESSED BY THE LACK OF JET DYNAMICS AND THE SYSTEM IS NOT LOADED WITH MOISTURE EITHER. FEEL OUR 40 POPS COVER IT WELL FOR SATURDAY. HOWEVER WILL INCREASE THE FORECAST TO 40 POPS INTO SATURDAY EVENING AS THE SHORT WAVE SHOULD CROSS THE CWA IN THIS TIME FRAME. SEVERE POTENTIAL LOOKS VERY LOW GIVEN THE WEAK WIND FIELDS. MUCH OF THE ACTION APPEARS TO BE EAST OF THE AREA INTO SUNDAY...ALTHOUGH THE SE CWA MAY STILL SEE LINGERING SHOWERS/STORMS. THEREFORE...REMOVED POPS OVER THE NW AND LOWERED POPS OVER THE CENTRAL CWA AS THE UPPER SUPPORT MOVES SOUTH AND EAST. ALSO BUMPED UP MAX TEMPS SEVERAL DEGREES WITH MORE SUNSHINE EXPECTED. .LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY) ISSUED AT 337 AM EDT FRI JUL 13 2012 GIVEN THE PREVAILING AND TO SOME EXTENT EXPANDING DROUGHT OVER SOUTHWEST LOWER MICHIGAN... THE MAIN ISSUE IS CAN WE GET A SIGNIFICANT RAINFALL EVENT DURING THIS TIME? THE OTHER ISSUE IS THE TEMPERATURE...JUST HOW HOT DOES IT GET THIS COMING WEEK? THROUGH THURSDAY MORNING THE MODELS ARE LARGELY IN AGREEMENT AT THE JET STREAM LEVEL AS TO WHAT WILL HAPPEN. A SYSTEM NOW IN THE GULF OF ALASKA RACES ACROSS SOUTHERN CANADA AND PHASES WITH THE CLOSED UPPER LOW CURRENTLY OVER NW CANADA BUT BY THEN EAST OF HUDSON BAY. THIS CREATES AN UPPER LEVEL JET ASSIST FOR THE GULF OF ALASKA SYSTEM AS IT PHASES WITH THE CLOSED UPPER LOW. THAT IN TURN HELPS PUSH THE COLD FRONT SOUTH INTO THE SOUTHERN GREAT LAKES TUESDAY NIGHT INTO WEDNESDAY. IT IS AT THIS TIME WE STAND OUR BEST CHANCE OF SEEING SHOWERS AND THUNDERSTORMS ACROSS THE CWA. BEYOND THAT SOME ISSUES DEVELOP WITH THE NEXT PACIFIC SYSTEM LATE IN THE WEEK WHERE THE ECMWF IS STRONGER WITH THE SYSTEM THAT COMES ON SHORE IN THE PACIFIC NORTHWEST WHICH LEADS TO A LARGER UP-STREAM SUBTROPICAL HIGH. AS FOR OUR CONVECTION WITH THE COLD FRONT TUESDAY NIGHT... THAT BY ITSELF IS AN ISSUE. THE FRONT IS COMING THROUGH EARLY WEDNESDAY MORNING. NOT THE BEST TIME FOR CONVECTION IN THE FIRST PLACE. ON THE UP SIDE THE PRECIPITABLE WATER WILL BE OVER 2 INCHES (NEARLY DOUBLE NORMAL). ALSO THERE IS A TAIL OF UPPER LEVEL JET CORE CROSSING CENTRAL LOWER MICHIGAN TUESDAY NIGHT INTO WEDNESDAY MORNING THAT PUTS SOUTHWEST MICHIGAN IN THE RIGHT ENTRANCE REGION OF THE JET CORE (THAT WILL HELP WITH THE LIFT FOR CONVECTION). THERE IS CONVERGENCE ON THE SURFACE FRONT... ANOTHER GOOD THING. THE MOST UNSTABLE CAP IS BETWEEN 2000 AND 3000 J/KG EVEN AT NIGHT SO THAT IS A POSITIVE TOO. THE DEEP LAYER SHEAR IS NEAR 30 KNOTS DUE TO JET CORE MOVING THROUGH. SO IT WOULD SEEM WE DO HAVE A SHOT AT SOME CONVECTION WITH THE FRONT SO I HAVE BETWEEN 30 AND 40 PCT FOR NOW AND CALLED THAT GOOD. THE OVER RIDING STORY FOR THIS WEEK THROUGH IS THE POLAR JET STREAM STAYS WELL NORTH OF 55 NORTH THROUGH THIS COMING WEEK (BASED ON THE PV15 WIND MAX). THAT MEANS WHATEVER COLD PUSH WE GET WILL BE FEEBLE AT BEST AND SHORT LIVED. OVERALL OUR HOT WEATHER WILL LIKELY CONTINUE THROUGH THE WEEK WITH ONLY A MINOR COOL OFF (NOT EVEN TO NORMAL) WED/THU. GIVEN THE GFS MAX TEMP FOR THE 84 HOUR THROUGH 240 HOUR (8TH THROUGH THE 11TH) AS A MEAN AVERAGE ERROR OF OVER 8 DEGREES ON THE HIGH TEMPERATURE AND BIAS IS ABOUT THE SAME... WHILE THE ECMWF FOR THE TIME HAS A MEAN AVERAGE ERROR OF ONLY 4 DEGREES... I PUSHED THE HIGHS UP TO BE CLOSER TO THE ECMWF VALUES THROUGH THE WEEK. NOTE: CURIOUSLY THE ERROR FOR THE LOW TEMPS FAVORS THE GFS SO I DID NOT DO MUCH WITH THE LOWS. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING) ISSUED AT 650 AM EDT FRI JUL 13 2012 VFR CIGS/VSBY ARE EXPECTED THROUGH SATURDAY MORNING. THERE COULD BE A FEW THUNDERSTORMS AROUND MID AFTERNOON INTO THE EARLY EVENING SO I CONTINUED THE VCTS IN ALL THE INLAND TAF SITES TODAY. ANY STORM WILL BE SHORT LIVED BUT THERE COULD BE A BRIEF LOWERING OF THE VISIBILITY IN THE HEAVER SHOWERS. CLOUD BASES SHOULD STILL BE IN THE 6000 TO 7000 FT RANGE THIS MORNING AND MORE LIKE 8000 TO 9000 FT AGL THIS AFTERNOON (BASED ON 06Z NAM12 AND 09Z RAP SOUNDINGS). && .MARINE... ISSUED AT 337 AM EDT FRI JUL 13 2012 A LIGHT SOUTHERLY FLOW WILL CONTINUE THROUGH SATURDAY...THEN VEER TO THE WEST LATE SATURDAY NIGHT WITH THE FRONT COMING THROUGH. WAVE ACTION SHOULD REMAIN LOW. && .HYDROLOGY... ISSUED AT 337 AM EDT FRI JUL 13 2012 PCPN LATE TONIGHT INTO EARLY SUNDAY STILL LOOKS RATHER LIGHT...NOT THE DROUGHT BUSTER THAT WE NEED. CAN NOT RULE OUT LOCALIZED HEAVY RAINS...BUT MOST RIVER BASIN AVERAGES WILL BE UNDER A QUARTER INCH...HAVING VERY LITTLE HYDRO IMPACT. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. && $$ UPDATE...WDM SYNOPSIS...JK SHORT TERM...JK LONG TERM...WDM AVIATION...WDM HYDROLOGY...JK MARINE...JK
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1236 PM CDT FRI JUL 13 2012 .AVIATION... /18Z TAF ISSUANCE/ TWO CONCERNS THIS TAF CYCLE. THE FIRST IS SHRA/TSRA CHANCES THIS AFTERNOON AND EVENING WHILE THE OTHER IS MVFR OR LOWER CEILINGS/VISIBILITIES IN FOG LATE TONIGHT. EARLY THIS AFTERNOON SHOWERS WERE BEGINNING TO INCREASE IN COVERAGE BETWEEN KAXN AND KSTC. THIS IS ALONG THE SURFACE FRONT AND UPPER LOW/TROF ALOFT. SHORT TERM GUIDANCE IS IN PRETTY GOOD AGREEMENT THAT ACTIVITY SHOULD CONTINUE TO INCREASE IN COVERAGE THIS AFTERNOON AND SPREAD SOUTHEAST. KMSP...KRNH AND KEAU SEEM TO HAVE THE BEST CHANCE FOR SHRA/TSRA BUT CONFIDENCE IS LOW ON COVERAGE AT ANY ONE SITE. THEREFORE...CONTINUED VCSH/VCTS. THE WESTERN TERMINALS MAY SEE A BRIEF SHOWER AS WELL WITH VCSH INDICATED AT KAXN AND KRWF. SCT- BKN040-050 WILL BE COMMON THIS AFTERNOON WITH A MID LEVEL CEILING ABOVE. WINDS THIS AFTERNOON WILL BE SOUTH AT NEAR 10 KNOTS FROM KMSP ON EAST WITH SOUTHWEST TO WEST WINDS LESS THAN 10 KNOTS TO THE WEST. THE FRONTAL BOUNDARY ACROSS WESTERN MN WILL WASH OUT TONIGHT ACROSS WESTERN WI AND SOUTHERN MN. LOW LEVEL MOISTURE COMBINED WITH LIGHT WINDS AND THE POTENTIAL FOR ADDED GROUND MOISTURE FROM AFTERNOON/EVENING SHOWERS SHOULD LEAD TO MVFR OR LOWER CONDITIONS AT KRNH AND KEAU DURING THE LATE NIGHT HOURS. CONFIDENCE IS PRETTY HIGH AND INDICATED MVFR OR LESS AFTER 08Z. IT/S QUITE CONCEIVABLE THAT THE FOG COULD DEVELOP AS EARLY AS 04Z-06Z...DEPENDING ON HOW MUCH RAIN OCCURS IN THE EVENING ALONG WITH THE CLEARING TREND. KMSP...SHOWERS POSSIBLE AFTER 20Z WITH THUNDER CHANCES INCREASING AFTER 22Z AND LASTING INTO THE EARLY EVENING. SMALL THREAT FOR 5-6SM IN FOG/HAZE TOWARD DAYBREAK SATURDAY WITH LIGHT WINDS. /OUTLOOK/ SATURDAY AFTERNOON/NIGHT...VFR. WINDS NORTHERLY AT 5 TO 10 KTS. SUNDAY...VFR. WINDS SE AT 5-15 KTS. MONDAY...VFR. WINDS S-SW 10-20 KTS. && .DISCUSSION... /ISSUED 325 AM CDT FRI JUL 13 2012/ THE UPCOMING SEVEN DAYS LOOKS TO BE RELATIVELY QUIET FROM A PCPN PERSPECTIVE... WITH THE BEST CHANCES BEING OVER THE NEXT 24 HOURS... BUT IT STARTING TO LOOK MORE INTERESTING WITH RESPECT TO A FEW CHANCES FOR EXCESSIVE HEAT. IN THE BIG PICTURE... THE LATEST WATER VAPOR IMAGERY AND RAP UPPER AIR ANALYSIS SHOW A FAIRLY HEALTHY SHORTWAVE MOVING THROUGH THE REGION AT THE CURRENT TIME... WITH TWO MAIN PV ANOMALIES AND AREAS OF ENHANCED FORCING. ONE CAN BE SEEN DROPPING SOUTHEAST THROUGH SOUTHEAST SOUTH DAKOTA AT THE CURRENT TIME... AND IS HELPING TO ENHANCE THE PCPN OUT AHEAD OF IT OVER THE SOUTHERN PART OF MINNESOTA. THE SECOND ANOMALY IS OVER NORTHEAST NORTH DAKOTA... AND IS SLOWLY SLIDING EAST WITH TIME... AND HELPING TO KEEP SOME PCPN GOING IN THAT AREA. ZOOMING OUT... AN AMPLIFIED RIDGE REMAINS OVER THE WESTERN CONUS... WITH AN UPPER TROUGH OVER THE PACIFIC NORTHWEST. THE GENERAL THEME OVER THE NEXT 24 TO 36 HOURS WILL BE FOR THE SHORTWAVE CURRENTLY TO OUR WEST TO DROP SLOWLY SOUTHEAST AND HELP PUSH THE SURFACE TROUGH/FRONT THROUGH THE AREA TODAY THROUGH SATURDAY... BRINGING CHANCES FOR SHRA/TSRA TO THE AREA. AFTER THAT WE WILL SEE THE RIDGE OVER THE ROCKIES BUILD INTO THE AREA... AND BRING INCREASINGLY WARM TEMPERATURES INTO THE AREA THROUGH MONDAY. WE SHOULD THEN SEE SOME BRIEF DEPRESSION IN THE UPPER HEIGHTS OVER THE AREA... BUT BY THE MIDDLE OF THE WEEK THE UPPER RIDGE LOOKS TO RE-AMPLIFY OVER THE CENTER OF THE COUNTRY. BY THE END OF THE WEEK THERE IS A FAIR AMOUNT OF DISAGREEMENT BETWEEN THE GFS AND ECMWF... WITH THE GFS DROPPING AND UPPER TROUGH INTO EASTERN CANADA AND DEVELOPING NORTHWEST FLOW OVER US... WHILE THE ECMWF CONTINUES TO BUILD THE UPPER RIDGE AND WOULD REALLY HAVE US COOKING BY THE END OF THE WEEK. THE ECMWF HAS BEEN FAIRLY CONSISTENT WITH THE IDEA THE PAST FEW RUNS... SO IT WILL CERTAINLY BE SOMETHING TO MONITOR. AT THIS POINT... A VERY WARM MONDAY LOOKS TO BE A GOOD BET... WITH ANOTHER PERHAPS WARMER SPAN OF WEATHER DEVELOPING BY THE END OF THE WEEK THROUGH THE FOLLOWING WEEKEND. FOR TODAY... WE SHOULD CONTINUE TO SEE SOME SCATTERED SHRA/TSRA MIGRATE SLOWLY EAST THROUGH THE DAY AS THE SURFACE TROUGH PUSHES EAST AHEAD OF UPPER WAVE. THE LOW LEVEL CONVERGENCE/UPPER LEVEL DIVERGENCE COUPLET LOOKS TO PUSH EAST OF THE I-35 CORRIDOR BY THIS AFTERNOON... SO THE BEST CHANCE FOR MORE WIDESPREAD PCPN WILL BE OVER THE EASTERN PART OF THE CWFA... ALONG WITH THE MAIN POTENTIAL FOR ANY SEVERE STORMS. HOWEVER... WITH THE UPPER TROUGH MOVING SO SLOWLY TODAY AND TONIGHT... WE COULD CERTAINLY SEE SOME LINGERING SHRA BEHIND THE SURFACE BOUNDARY BENEATH THE UPPER PV ANOMALY AND ASSOCIATED MID-LEVEL COLD POOL. IN TERMS OF SEVERE WEATHER POTENTIAL... THINGS STILL LOOK LIKE THE HAVE THE PAST SEVERAL DAYS... WITH DECENT MLCAPE VALUES AOA 1500 J/KG TODAY INTO THIS EVENING... BUT MEAGER DEEP LAYER AND LOW LEVEL SHEAR. SO... STILL LOOKS LIKE WE/LL MAINLY BE DEALING WITH MULTI-CELL PULSE STORMS... WITH THE PRIMARY THREAT BEING MARGINALLY SEVERE HAIL AND PERHAPS SOME DOWNBURST WIND GUSTS GIVEN EXPECTED SURFACE DELTA THETA-E VALUES AOA 25K. SOME PCPN COULD LINGER OVER THE EASTERN PART OF THE AREA FOR A GOOD PART OF SATURDAY GIVEN THE SLOW EASTWARD MIGRATION OF THE UPPER WAVE. HOWEVER... BY SATURDAY NIGHT WE SHOULD SEE UPPER RIDGING WORK BACK ACROSS THE AREA... WITH A SURFACE RIDGE NOSING DOWN FROM CENTRAL CANADA AS WELL. FAIRLY ROBUST RETURN FLOW LOOKS TO SETUP SUNDAY AFTERNOON... PUSHING THE WARM FRONT WELL NORTH THROUGH THE AREA BY EVENING. WE WILL THEN SEE LOW PRESSURE ORGANIZE OVER THE HIGH PLAINS SUNDAY NIGHT INTO MONDAY... WITH THE WARM SECTOR BECOME WELL ESTABLISHED OVER OUR AREA. CHANCES FOR PCPN ON MONDAY AS THIS LOW PUSHES EAST LOOK LIKE THEY WILL BE CONFINED TO THE NORTH OF OUR AREA CLOSER TO THE WARM FRONTAL BOUNDARY AS 700MB TEMPERATURES AOA 12C ENCOMPASS ALL OF CENTRAL AND SOUTHERN MINNESOTA. THE COLD FRONT WILL EVENTUALLY DROP SOUTH THROUGH THE AREA MONDAY NIGHT AND TUESDAY AS THE SURFACE LOW MOVES OFF INTO THE GREAT LAKES... AND WE COULD SEE SOME SHRA/TSRA DROP THROUGH THE AREA AT THAT TIME AS WE FINALLY PUSH THE CAP SOUTH OF THE REGION. A BRIEF SHOT OF COOLER AND DRIER AIR LOOKS TO WORK INTO THE AREA TUESDAY NIGHT THROUGH WEDNESDAY AS 500MB HEIGHTS FALL AND A DECENT SURFACE HIGH SETTLES SOUTH INTO THE AREA FROM CANADA. HOWEVER... AS WE/VE SEEN MOST OF THE SUMMER... WE WON/T HAVE NEAR OR SLIGHTLY BELOW NORMAL TEMPERATURES REMAINING OVER THE AREA FOR TOO LONG... AND RETURN FLOW WILL SET BACK UP BY THURSDAY. AS SOUTHWESTERLY FLOW DEVELOPS AND STARTS TO BRING WARMER TEMPERATURES AND MOISTURE BACK INTO THE AREA... WE COULD SEE SOME PCPN DEVELOP OVER THE AREA... SO INCLUDED SOME POPS ON THURSDAY TO ACCOUNT FOR THAT SCENARIO. AFTER THURSDAY... AND BEYOND THE CURRENT FORECAST PERIOD... IS THE POINT AT WHICH THE GFS AND ECMWF START TO DIVERGE QUITE A BIT... AND THERE IS A FAIR AMOUNT OF SPREAD IN THE GEFS AT THIS POINT AS WELL... WITH SOME MEMBERS SUGGESTING SOLUTIONS CLOSER TO THAT OF THE ECMWF. IN A NUTSHELL... THE ECMWF REALLY BUILDS THE UPPER RIDGE OVER THE CENTRAL CONUS AND INTO SOUTHERN CANADA... WHILE THE GFS HOLDS A DEEP UPPER TROUGH OVER EASTERN CANADA... AND MANAGES TO KEEP THE UPPER RIDGE AT BAY TO OUR WEST. SHOULD THINGS PAN OUT AS THE ECMWF SUGGESTS... WE COULD BE LOOKING AT A PROLONGED SPELL OF WELL ABOVE NORMAL TEMPERATURES FROM THE END OF THE WEEK INTO THE FIRST PART OF THE FOLLOWING WEEK. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ RAH/TRH
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
704 AM CDT FRI JUL 13 2012 .UPDATED FOR 12Z AVIATION DISCUSSION... && .DISCUSSION... THE UPCOMING SEVEN DAYS LOOKS TO BE RELATIVELY QUIET FROM A PCPN PERSPECTIVE... WITH THE BEST CHANCES BEING OVER THE NEXT 24 HOURS... BUT IT STARTING TO LOOK MORE INTERESTING WITH RESPECT TO A FEW CHANCES FOR EXCESSIVE HEAT. IN THE BIG PICTURE... THE LATEST WATER VAPOR IMAGERY AND RAP UPPER AIR ANALYSES SHOW A FAIRLY HEALTHY SHORTWAVE MOVING THROUGH THE REGION AT THE CURRENT TIME... WITH TWO MAIN PV ANOMALIES AND AREAS OF ENHANCED FORCING. ONE CAN BE SEEN DROPPING SOUTHEAST THROUGH SOUTHEAST SOUTH DAKOTA AT THE CURRENT TIME... AND IS HELPING TO ENHANCE THE PCPN OUT AHEAD OF IT OVER THE SOUTHERN PART OF MINNESOTA. THE SECOND ANOMALY IS OVER NORTHEAST NORTH DAKOTA... AND IS SLOWLY SLIDING EAST WITH TIME... AND HELPING TO KEEP SOME PCPN GOING IN THAT AREA. ZOOMING OUT... AN AMPLIFIED RIDGE REMAINS OVER THE WESTERN CONUS... WITH AN UPPER TROUGH OVER THE PACIFIC NORTHWEST. THE GENERAL THEME OVER THE NEXT 24 TO 36 HOURS WILL BE FOR THE SHORTWAVE CURRENTLY TO OUR WEST TO DROP SLOWLY SOUTHEAST AND HELP PUSH THE SURFACE TROUGH/FRONT THROUGH THE AREA TODAY THROUGH SATURDAY... BRINGING CHANCES FOR SHRA/TSRA TO THE AREA. AFTER THAT WE WILL SEE THE RIDGE OVER THE ROCKIES BUILD INTO THE AREA... AND BRING INCREASINGLY WARM TEMPERATURES INTO THE AREA THROUGH MONDAY. WE SHOULD THEN SEE SOME BRIEF DEPRESSION IN THE UPPER HEIGHTS OVER THE AREA... BUT BY THE MIDDLE OF THE WEEK THE UPPER RIDGE LOOKS TO RE-AMPLIFY OVER THE CENTER OF THE COUNTRY. BY THE END OF THE WEEK THERE IS A FAIR AMOUNT OF DISAGREEMENT BETWEEN THE GFS AND ECMWF... WITH THE GFS DROPPING AND UPPER TROUGH INTO EASTERN CANADA AND DEVELOPING NORTHWEST FLOW OVER US... WHILE THE ECMWF CONTINUES TO BUILD THE UPPER RIDGE AND WOULD REALLY HAVE US COOKING BY THE END OF THE WEEK. THE ECMWF HAS BEEN FAIRLY CONSISTENT WITH THE IDEA THE PAST FEW RUNS... SO IT WILL CERTAINLY BE SOMETHING TO MONITOR. AT THIS POINT... A VERY WARM MONDAY LOOKS TO BE A GOOD BET... WITH ANOTHER PERHAPS WARMER SPAN OF WEATHER DEVELOPING BY THE END OF THE WEEK THROUGH THE FOLLOWING WEEKEND. FOR TODAY... WE SHOULD CONTINUE TO SEE SOME SCATTERED SHRA/TSRA MIGRATE SLOWLY EAST THROUGH THE DAY AS THE SURFACE TROUGH PUSHES EAST AHEAD OF UPPER WAVE. THE LOW LEVEL CONVERGENCE/UPPER LEVEL DIVERGENCE COUPLET LOOKS TO PUSH EAST OF THE I-35 CORRIDOR BY THIS AFTERNOON... SO THE BEST CHANCE FOR MORE WIDESPREAD PCPN WILL BE OVER THE EASTERN PART OF THE CWFA... ALONG WITH THE MAIN POTENTIAL FOR ANY SEVERE STORMS. HOWEVER... WITH THE UPPER TROUGH MOVING SO SLOWLY TODAY AND TONIGHT... WE COULD CERTAINLY SEE SOME LINGERING SHRA BEHIND THE SURFACE BOUNDARY BENEATH THE UPPER PV ANOMALY AND ASSOCIATED MID-LEVEL COLD POOL. IN TERMS OF SEVERE WEATHER POTENTIAL... THINGS STILL LOOK LIKE THE HAVE THE PAST SEVERAL DAYS... WITH DECENT MLCAPE VALUES AOA 1500 J/KG TODAY INTO THIS EVENING... BUT MEAGER DEEP LAYER AND LOW LEVEL SHEAR. SO... STILL LOOKS LIKE WE/LL MAINLY BE DEALING WITH MULTI-CELL PULSE STORMS... WITH THE PRIMARY THREAT BEING MARGINALLY SEVERE HAIL AND PERHAPS SOME DOWNBURST WIND GUSTS GIVEN EXPECTED SURFACE DELTA THETA-E VALUES AOA 25K. SOME PCPN COULD LINGER OVER THE EASTERN PART OF THE AREA FOR A GOOD PART OF SATURDAY GIVEN THE SLOW EASTWARD MIGRATION OF THE UPPER WAVE. HOWEVER... BY SATURDAY NIGHT WE SHOULD SEE UPPER RIDGING WORK BACK ACROSS THE AREA... WITH A SURFACE RIDGE NOSING DOWN FROM CENTRAL CANADA AS WELL. FAIRLY ROBUST RETURN FLOW LOOKS TO SETUP SUNDAY AFTERNOON... PUSHING THE WARM FRONT WELL NORTH THROUGH THE AREA BY EVENING. WE WILL THEN SEE LOW PRESSURE ORGANIZE OVER THE HIGH PLAINS SUNDAY NIGHT INTO MONDAY... WITH THE WARM SECTOR BECOME WELL ESTABLISHED OVER OUR AREA. CHANCES FOR PCPN ON MONDAY AS THIS LOW PUSHES EAST LOOK LIKE THEY WILL BE CONFINED TO THE NORTH OF OUR AREA CLOSER TO THE WARM FRONTAL BOUNDARY AS 700MB TEMPERATURES AOA 12C ENCOMPASS ALL OF CENTRAL AND SOUTHERN MINNESOTA. THE COLD FRONT WILL EVENTUALLY DROP SOUTH THROUGH THE AREA MONDAY NIGHT AND TUESDAY AS THE SURFACE LOW MOVES OFF INTO THE GREAT LAKES... AND WE COULD SEE SOME SHRA/TSRA DROP THROUGH THE AREA AT THAT TIME AS WE FINALLY PUSH THE CAP SOUTH OF THE REGION. A BRIEF SHOT OF COOLER AND DRIER AIR LOOKS TO WORK INTO THE AREA TUESDAY NIGHT THROUGH WEDNESDAY AS 500MB HEIGHTS FALL AND A DECENT SURFACE HIGH SETTLES SOUTH INTO THE AREA FROM CANADA. HOWEVER... AS WE/VE SEEN MOST OF THE SUMMER... WE WON/T HAVE NEAR OR SLIGHTLY BELOW NORMAL TEMPERATURES REMAINING OVER THE AREA FOR TOO LONG... AND RETURN FLOW WILL SET BACK UP BY THURSDAY. AS SOUTHWESTERLY FLOW DEVELOPS AND STARTS TO BRING WARMER TEMPERATURES AND MOISTURE BACK INTO THE AREA... WE COULD SEE SOME PCPN DEVELOP OVER THE AREA... SO INCLUDED SOME POPS ON THURSDAY TO ACCOUNT FOR THAT SCENARIO. AFTER THURSDAY... AND BEYOND THE CURRENT FORECAST PERIOD... IS THE POINT AT WHICH THE GFS AND ECMWF START TO DIVERGE QUITE A BIT... AND THERE IS A FAIR AMOUNT OF SPREAD IN THE GEFS AT THIS POINT AS WELL... WITH SOME MEMBERS SUGGESTING SOLUTIONS CLOSER TO THAT OF THE ECMWF. IN A NUTSHELL... THE ECMWF REALLY BUILDS THE UPPER RIDGE OVER THE CENTRAL CONUS AND INTO SOUTHERN CANADA... WHILE THE GFS HOLDS A DEEP UPPER TROUGH OVER EASTERN CANADA... AND MANAGES TO KEEP THE UPPER RIDGE AT BAY TO OUR WEST. SHOULD THINGS PAN OUT AS THE ECMWF SUGGESTS... WE COULD BE LOOKING AT A PROLONGED SPELL OF WELL ABOVE NORMAL TEMPERATURES FROM THE END OF THE WEEK INTO THE FIRST PART OF THE FOLLOWING WEEK. && .AVIATION.../12Z TAF ISSUANCE/ AN UPPER LEVEL DISTURBANCE WILL SLIDE ACROSS THE REGION OVER THE NEXT 24 HOURS AND CAUSE SOME SHOWERS AND THUNDERSTORMS TO DEVELOP. THESE ARE ALREADY ONGOING NEAR THE MN/WI BORDER. EXPECT THESE PULSE STORMS TO PERCOLATE THROUGHOUT THE DAY...WITH BETTER CHANCES DURING THE LATE AFTERNOON AND EARLY EVENING AT THE EASTERN SITES. KMSP...SHOWERS AND THUNDERSTORMS SEEM TO BE REDEVELOPING ON THE EASTERN SIDE OF THE METRO THIS MORNING. ANTICIPATING A BREAK THIS MORNING THROUGH THE EARLY AFTERNOON BEFORE MORE WIDESPREAD SHOWERS DEVELOP ONCE AGAIN. THIS CONVECTION WILL BE VERY PULSE-LIKE IN NATURE...SO CURRENTLY JUST HAVE A VC-GROUP. THIS WILL LIKELY NEED TO BE FINE TUNED LATER TODAY...BUT DIDNT FEEL CONFIDENT WITH SEVERAL HOURS OF THUNDER. /OUTLOOK/ SATURDAY...VFR WITH TSRA ENDING. WINDS N AT 5 KT. SUNDAY...VFR. WINDS W AT 10G15KT. MONDAY...VFR. WINDS SSW AT 10G15KT. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ TRH/JRB
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
325 AM CDT FRI JUL 13 2012 .DISCUSSION... THE UPCOMING SEVEN DAYS LOOKS TO BE RELATIVELY QUIET FROM A PCPN PERSPECTIVE... WITH THE BEST CHANCES BEING OVER THE NEXT 24 HOURS... BUT IT STARTING TO LOOK MORE INTERESTING WITH RESPECT TO A FEW CHANCES FOR EXCESSIVE HEAT. IN THE BIG PICTURE... THE LATEST WATER VAPOR IMAGERY AND RAP UPPER AIR ANALYSES SHOW A FAIRLY HEALTHY SHORTWAVE MOVING THROUGH THE REGION AT THE CURRENT TIME... WITH TWO MAIN PV ANOMALIES AND AREAS OF ENHANCED FORCING. ONE CAN BE SEEN DROPPING SOUTHEAST THROUGH SOUTHEAST SOUTH DAKOTA AT THE CURRENT TIME... AND IS HELPING TO ENHANCE THE PCPN OUT AHEAD OF IT OVER THE SOUTHERN PART OF MINNESOTA. THE SECOND ANOMALY IS OVER NORTHEAST NORTH DAKOTA... AND IS SLOWLY SLIDING EAST WITH TIME... AND HELPING TO KEEP SOME PCPN GOING IN THAT AREA. ZOOMING OUT... AN AMPLIFIED RIDGE REMAINS OVER THE WESTERN CONUS... WITH AN UPPER TROUGH OVER THE PACIFIC NORTHWEST. THE GENERAL THEME OVER THE NEXT 24 TO 36 HOURS WILL BE FOR THE SHORTWAVE CURRENTLY TO OUR WEST TO DROP SLOWLY SOUTHEAST AND HELP PUSH THE SURFACE TROUGH/FRONT THROUGH THE AREA TODAY THROUGH SATURDAY... BRINGING CHANCES FOR SHRA/TSRA TO THE AREA. AFTER THAT WE WILL SEE THE RIDGE OVER THE ROCKIES BUILD INTO THE AREA... AND BRING INCREASINGLY WARM TEMPERATURES INTO THE AREA THROUGH MONDAY. WE SHOULD THEN SEE SOME BRIEF DEPRESSION IN THE UPPER HEIGHTS OVER THE AREA... BUT BY THE MIDDLE OF THE WEEK THE UPPER RIDGE LOOKS TO RE-AMPLIFY OVER THE CENTER OF THE COUNTRY. BY THE END OF THE WEEK THERE IS A FAIR AMOUNT OF DISAGREEMENT BETWEEN THE GFS AND ECMWF... WITH THE GFS DROPPING AND UPPER TROUGH INTO EASTERN CANADA AND DEVELOPING NORTHWEST FLOW OVER US... WHILE THE ECMWF CONTINUES TO BUILD THE UPPER RIDGE AND WOULD REALLY HAVE US COOKING BY THE END OF THE WEEK. THE ECMWF HAS BEEN FAIRLY CONSISTENT WITH THE IDEA THE PAST FEW RUNS... SO IT WILL CERTAINLY BE SOMETHING TO MONITOR. AT THIS POINT... A VERY WARM MONDAY LOOKS TO BE A GOOD BET... WITH ANOTHER PERHAPS WARMER SPAN OF WEATHER DEVELOPING BY THE END OF THE WEEK THROUGH THE FOLLOWING WEEKEND. FOR TODAY... WE SHOULD CONTINUE TO SEE SOME SCATTERED SHRA/TSRA MIGRATE SLOWLY EAST THROUGH THE DAY AS THE SURFACE TROUGH PUSHES EAST AHEAD OF UPPER WAVE. THE LOW LEVEL CONVERGENCE/UPPER LEVEL DIVERGENCE COUPLET LOOKS TO PUSH EAST OF THE I-35 CORRIDOR BY THIS AFTERNOON... SO THE BEST CHANCE FOR MORE WIDESPREAD PCPN WILL BE OVER THE EASTERN PART OF THE CWFA... ALONG WITH THE MAIN POTENTIAL FOR ANY SEVERE STORMS. HOWEVER... WITH THE UPPER TROUGH MOVING SO SLOWLY TODAY AND TONIGHT... WE COULD CERTAINLY SEE SOME LINGERING SHRA BEHIND THE SURFACE BOUNDARY BENEATH THE UPPER PV ANOMALY AND ASSOCIATED MID-LEVEL COLD POOL. IN TERMS OF SEVERE WEATHER POTENTIAL... THINGS STILL LOOK LIKE THE HAVE THE PAST SEVERAL DAYS... WITH DECENT MLCAPE VALUES AOA 1500 J/KG TODAY INTO THIS EVENING... BUT MEAGER DEEP LAYER AND LOW LEVEL SHEAR. SO... STILL LOOKS LIKE WE/LL MAINLY BE DEALING WITH MULTI-CELL PULSE STORMS... WITH THE PRIMARY THREAT BEING MARGINALLY SEVERE HAIL AND PERHAPS SOME DOWNBURST WIND GUSTS GIVEN EXPECTED SURFACE DELTA THETA-E VALUES AOA 25K. SOME PCPN COULD LINGER OVER THE EASTERN PART OF THE AREA FOR A GOOD PART OF SATURDAY GIVEN THE SLOW EASTWARD MIGRATION OF THE UPPER WAVE. HOWEVER... BY SATURDAY NIGHT WE SHOULD SEE UPPER RIDGING WORK BACK ACROSS THE AREA... WITH A SURFACE RIDGE NOSING DOWN FROM CENTRAL CANADA AS WELL. FAIRLY ROBUST RETURN FLOW LOOKS TO SETUP SUNDAY AFTERNOON... PUSHING THE WARM FRONT WELL NORTH THROUGH THE AREA BY EVENING. WE WILL THEN SEE LOW PRESSURE ORGANIZE OVER THE HIGH PLAINS SUNDAY NIGHT INTO MONDAY... WITH THE WARM SECTOR BECOME WELL ESTABLISHED OVER OUR AREA. CHANCES FOR PCPN ON MONDAY AS THIS LOW PUSHES EAST LOOK LIKE THEY WILL BE CONFINED TO THE NORTH OF OUR AREA CLOSER TO THE WARM FRONTAL BOUNDARY AS 700MB TEMPERATURES AOA 12C ENCOMPASS ALL OF CENTRAL AND SOUTHERN MINNESOTA. THE COLD FRONT WILL EVENTUALLY DROP SOUTH THROUGH THE AREA MONDAY NIGHT AND TUESDAY AS THE SURFACE LOW MOVES OFF INTO THE GREAT LAKES... AND WE COULD SEE SOME SHRA/TSRA DROP THROUGH THE AREA AT THAT TIME AS WE FINALLY PUSH THE CAP SOUTH OF THE REGION. A BRIEF SHOT OF COOLER AND DRIER AIR LOOKS TO WORK INTO THE AREA TUESDAY NIGHT THROUGH WEDNESDAY AS 500MB HEIGHTS FALL AND A DECENT SURFACE HIGH SETTLES SOUTH INTO THE AREA FROM CANADA. HOWEVER... AS WE/VE SEEN MOST OF THE SUMMER... WE WON/T HAVE NEAR OR SLIGHTLY BELOW NORMAL TEMPERATURES REMAINING OVER THE AREA FOR TOO LONG... AND RETURN FLOW WILL SET BACK UP BY THURSDAY. AS SOUTHWESTERLY FLOW DEVELOPS AND STARTS TO BRING WARMER TEMPERATURES AND MOISTURE BACK INTO THE AREA... WE COULD SEE SOME PCPN DEVELOP OVER THE AREA... SO INCLUDED SOME POPS ON THURSDAY TO ACCOUNT FOR THAT SCENARIO. AFTER THURSDAY... AND BEYOND THE CURRENT FORECAST PERIOD... IS THE POINT AT WHICH THE GFS AND ECMWF START TO DIVERGE QUITE A BIT... AND THERE IS A FAIR AMOUNT OF SPREAD IN THE GEFS AT THIS POINT AS WELL... WITH SOME MEMBERS SUGGESTING SOLUTIONS CLOSER TO THAT OF THE ECMWF. IN A NUTSHELL... THE ECMWF REALLY BUILDS THE UPPER RIDGE OVER THE CENTRAL CONUS AND INTO SOUTHERN CANADA... WHILE THE GFS HOLDS A DEEP UPPER TROUGH OVER EASTERN CANADA... AND MANAGES TO KEEP THE UPPER RIDGE AT BAY TO OUR WEST. SHOULD THINGS PAN OUT AS THE ECMWF SUGGESTS... WE COULD BE LOOKING AT A PROLONGED SPELL OF WELL ABOVE NORMAL TEMPERATURES FROM THE END OF THE WEEK INTO THE FIRST PART OF THE FOLLOWING WEEK. && .AVIATION.../06Z TAF ISSUANCE/ /ISSUED 1025 PM CDT THU JUL 12 2012/ LINE OF SCT SHWRS AND TSTMS EXTENDING FROM NW MN INTO SE SODAK CONTINUES TO MAKE PROGRESS EASTWARD AHEAD OF UPPER TROF IN THE DKTS. WEAK VORT IN NE SODAK NEAR KHON APPEARS TO BE LENDING SOME SUPPORT TO STORMS IN WC MN TOWARD KBKX AND KHON. MID LEVEL WARM ADVECTION SHUD HELP TO MAINTAIN SOME OF THIS ACTIVITY AS IT PUSHES EAST. PCPN WILL BE EAST OF AXN BY TAF ISSUE TIME...AND COVERAGE PROBBLY LOW ENUF TO CONFINE PCPN MENTION TO A VCNTY GROUP. WEAK SURFACE TROF WILL CONTINUE TO PROGRESS EAST INTO E MN FRI AFTN AND EXPECTED TO GENERATE ANOTHER ROUND OF SCT SHWRS AND TSTMS. KMSP...UPSTREAM CONVECTION MAY REACH THE MSP AREA ARND 08-09Z...BUT EXPECT COVERAGE TO REMAIN LOW ENUF TO CONFINE PCPN MENTION TO VCSH. WEAK SURFACE TROF NEAR THE DKTS BORDER AROUND 20-21Z AND SHUD BE SUFFICIENT INSTABILITY FOR ANOTHER ROUND OF SHWRS AND TSTMS...BUT EXPECT BETTER COVERAGE TO BE EAST OF MSP. /OUTLOOK/ SATURDAY...VFR WITH SHRA ENDING IN THE MORNING. WINDS NW AT 5 TO 10KTS. SUNDAY...VFR. WINDS SE AT 5-10 KTS. MONDAY...VFR. WINDS S-SW 10-15 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
533 PM CDT FRI JUL 13 2012 .UPDATE... ISSUED AT 421 PM CDT FRI JUL 13 2012 OUTFLOW DOMINATED CONVECTION CONTINUES TO STEADILY REDEVELOP SOUTHEAST TOWARD BEST SURFACE CONVERGENCE. BELIEVE THIS TREND WILL CONTINUE THIS EVENING WITH SCATTERED STORMS PROPOGATING/DEVELOPING AS FAR SOUTHEAST AS THE ST. LOUIS METROPOLITAN AREA BY DUSK. LOSS OF DIURNAL INSTABILITY WILL CAUSE COVERAGE OF CONVECTION TO RAPIDLY DECREASE AFTER SUNSET...BUT LIKE THE PAST FEW NIGHTS...ISOLATED SHOWERS AND STORMS COULD PERCOLATE INTO THE OVERNIGHT HOURS. CVKING && .SHORT TERM... ISSUED AT 248 PM CDT FRI JUL 13 2012 (TONIGHT) SCATTERED CONVECTION HAS DEVELOPED ACROSS THE NWRN HALF OF THE CWA AHEAD OF A PV ANOMALY THAT WAS LOCATED OVER IA PER WATER VAPOR IMAGERY AND RAP 1.5 PVU FIELDS. MAINLY PULSE-TYPE THUNDERSTORMS ARE EXPECTED DUE TO WEAK SHEAR COMBINED WITH LITTLE CINH AND A FEW THOUSAND J/KG OF CAPE. DRY SUBCLOUD LAYER AND A WELL-MIXED BOUNDARY LAYER WILL ONCE AGAIN SUPPORT OCCASIONAL DOWNBURSTS WHEN THE CORES OF THE STRONGEST STORMS COLLAPSE HOWEVER WIDESPREAD SEVERE WEATHER IS NOT EXPECTED AT THIS TIME. PCPN COVERAGE SHOULD DIMINISH LATER THIS EVENING WITH THE LOSS OF DAYTIME HEATING HOWEVER A FEW AREAS OF ELEVATED CONVECTION MIGHT CONTINUE TO PERCOLATE OVERNIGHT AS THE SHORTWAVE MOVES INTO NRN MO. KANOFSKY/CARNEY && .LONG TERM... ISSUED AT 248 PM CDT FRI JUL 13 2012 (TOMORROW THROUGH NEXT THURSDAY) VORT MAX MOVING ACROSS THE UPPER MIDWEST AND ITS ASSOCIATED SFC TROF WILL PROVIDE BOTH A SOURCE OF LARGE SCALE LIFT AND A LOW LEVEL FOCUSING MECHANISM FOR SCT TSRA/SHRA TOMORROW. GENERALLY PULSE-TYPE THUNDERSTORMS ARE EXPECTED DUE TO WEAK SHEAR. ISOLATED DIURNAL PCPN MAY REDEVELOP AND LINGER ACROSS THE SERN HALF OF THE CWA ON SUN AND MON AS THE TROF SETTLES SEWD AND THE ELONGATED VORTICITY AXIS SHEARS OUT. A GRADUAL WARMING TREND IS EXPECTED OVER THE NEXT SEVERAL DAYS AS AN UPPER LEVEL RIDGE BUILDS EWD. H85 TEMPERATURES OF 20-24 DEG C WOULD SUPPORT AFTN HIGHS RANGING FROM THE MID 90S TO NEAR THE CENTURY MARK. THE CENTRAL REGION ALLBLEND INITIALIZATION REMAINS CONTAMINATED BY INCORRECT GFS OUTPUT /NCEP STAFF CONTINUE TO TROUBLESHOOT BUT HAVE NOT YET IDENTIFIED THE SOURCE OF THE PROBLEM/ THEREFORE I DEVIATED SIGNIFICANTLY FROM THE RECOMMENDED INITIALIZATION TO REDUCE POPS AND RAISE TEMPS ON DAYS 4-7. A WEAK SFC FRONT WILL APPROACH THE CWA ON WED/THU AND MOISTURE POOLING AHEAD OF THE FRONT COULD DRIVE HEAT INDEX READINGS OVER 105 DEG F IN SOME AREAS. ISOLATED TO SCATTERED THUNDERSTORMS WILL BE POSSIBLE THROUGH THE EXTENDED PD HOWEVER THERE ARE NO STRONG SIGNALS TO SUPPORT HIGHER THAN SCHC POPS ACROSS MO/IL WHICH REMAINS IN A MODERATE TO SEVERE DROUGHT. KANOFSKY && .AVIATION... ISSUED AT 527 PM CDT FRI JUL 13 2012 LINE OF SCATTERED THUNDERSTORMS FROM CENTRAL MISSOURI TO WEST CENTRAL ILLINOIS HAS PRODUCED QUITE AN OUTFLOW THAT IS MOVING SOUTHEAST TOWARD THE ST. LOUIS METRO TAF SITES. THIS WILL SWING WINDS AROUND TO THE NORTHWEST WITH GUSTS TO 25KT AROUND 00Z. COULD SEE THUNDERSTORMS REDEVELOP ALONG THIS BOUNDARY AND HAVE INCLUDED A TEMPO FOR AN HOUR TO ACCOUNT FOR THIS. OF COURSE THIS WILL BE NOWCASTED WITH LATEST RADAR TRENDS. CONVECTION SHOULD WEAKEN WITH LOSS OF DAYTIME HEATING AFTER SUNSET...ALTHOUGH A FEW SHOWERS COULD LINGER GIVEN VICINITY OF WEAK MID/UPPER LEVEL TROF. WIND WILL BE LIGHT AND VARIABLE OVERNIGHT. HAVE A RENEWED CHANCE OF SCATTERED CONVECTION TOMORROW AFTERNOON FOR ST. LOUIS METRO TAF SITES AS 500MB SHEAR AXIS IS FORECAST TO BE OVERHEAD. HAVE HANDLED THIS THREAT WITH A PROB30 GROUP. SPECIFICS FOR KSTL... EXPECT OUTFLOW BOUNDARY TO IMPACT TERMINAL AROUND 00Z WITH A WIND SHIFT TO THE NORTHWEST AND GUSTS TO 25KT. ALSO WILL BE WATCHING TO SEE IF THUNDERSTORMS CAN REDEVELOP ALONG THIS BOUNDARY. OTHERWISE...VFR CONDITIONS EXPECTED OVERNIGHT WITH WINDS BECOMING LIGHT AND VARIABLE. A RENEWED THREAT OF THUNDERSTORMS TOMORROW AFTERNOON...BUT COVERAGE WILL REMAIN SCT...SO HAVE ONLY INCLUDED A PROB30 GROUP AT THIS TIME. CVKING && .LSX WATCHES/WARNINGS/ADVISORIES... MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
427 PM CDT FRI JUL 13 2012 .UPDATE... ISSUED AT 421 PM CDT FRI JUL 13 2012 OUTFLOW DOMINATED CONVECTION CONTINUES TO STEADILY REDEVELOP SOUTHEAST TOWARD BEST SURFACE CONVERGENCE. BELIEVE THIS TREND WILL CONTINUE THIS EVENING WITH SCATTERED STORMS PROPOGATING/DEVELOPING AS FAR SOUTHEAST AS THE ST. LOUIS METROPOLITAN AREA BY DUSK. LOSS OF DIURNAL INSTABILITY WILL CAUSE COVERAGE OF CONVECTION TO RAPIDLY DECREASE AFTER SUNSET...BUT LIKE THE PAST FEW NIGHTS...ISOLATED SHOWERS AND STORMS COULD PERCOLATE INTO THE OVERNIGHT HOURS. CVKING && .SHORT TERM... ISSUED AT 248 PM CDT FRI JUL 13 2012 (TONIGHT) SCATTERED CONVECTION HAS DEVELOPED ACROSS THE NWRN HALF OF THE CWA AHEAD OF A PV ANOMALY THAT WAS LOCATED OVER IA PER WATER VAPOR IMAGERY AND RAP 1.5 PVU FIELDS. MAINLY PULSE-TYPE THUNDERSTORMS ARE EXPECTED DUE TO WEAK SHEAR COMBINED WITH LITTLE CINH AND A FEW THOUSAND J/KG OF CAPE. DRY SUBCLOUD LAYER AND A WELL-MIXED BOUNDARY LAYER WILL ONCE AGAIN SUPPORT OCCASIONAL DOWNBURSTS WHEN THE CORES OF THE STRONGEST STORMS COLLAPSE HOWEVER WIDESPREAD SEVERE WEATHER IS NOT EXPECTED AT THIS TIME. PCPN COVERAGE SHOULD DIMINISH LATER THIS EVENING WITH THE LOSS OF DAYTIME HEATING HOWEVER A FEW AREAS OF ELEVATED CONVECTION MIGHT CONTINUE TO PERCOLATE OVERNIGHT AS THE SHORTWAVE MOVES INTO NRN MO. KANOFSKY/CARNEY && .LONG TERM... ISSUED AT 248 PM CDT FRI JUL 13 2012 (TOMORROW THROUGH NEXT THURSDAY) VORT MAX MOVING ACROSS THE UPPER MIDWEST AND ITS ASSOCIATED SFC TROF WILL PROVIDE BOTH A SOURCE OF LARGE SCALE LIFT AND A LOW LEVEL FOCUSING MECHANISM FOR SCT TSRA/SHRA TOMORROW. GENERALLY PULSE-TYPE THUNDERSTORMS ARE EXPECTED DUE TO WEAK SHEAR. ISOLATED DIURNAL PCPN MAY REDEVELOP AND LINGER ACROSS THE SERN HALF OF THE CWA ON SUN AND MON AS THE TROF SETTLES SEWD AND THE ELONGATED VORTICITY AXIS SHEARS OUT. A GRADUAL WARMING TREND IS EXPECTED OVER THE NEXT SEVERAL DAYS AS AN UPPER LEVEL RIDGE BUILDS EWD. H85 TEMPERATURES OF 20-24 DEG C WOULD SUPPORT AFTN HIGHS RANGING FROM THE MID 90S TO NEAR THE CENTURY MARK. THE CENTRAL REGION ALLBLEND INITIALIZATION REMAINS CONTAMINATED BY INCORRECT GFS OUTPUT /NCEP STAFF CONTINUE TO TROUBLESHOOT BUT HAVE NOT YET IDENTIFIED THE SOURCE OF THE PROBLEM/ THEREFORE I DEVIATED SIGNIFICANTLY FROM THE RECOMMENDED INITIALIZATION TO REDUCE POPS AND RAISE TEMPS ON DAYS 4-7. A WEAK SFC FRONT WILL APPROACH THE CWA ON WED/THU AND MOISTURE POOLING AHEAD OF THE FRONT COULD DRIVE HEAT INDEX READINGS OVER 105 DEG F IN SOME AREAS. ISOLATED TO SCATTERED THUNDERSTORMS WILL BE POSSIBLE THROUGH THE EXTENDED PD HOWEVER THERE ARE NO STRONG SIGNALS TO SUPPORT HIGHER THAN SCHC POPS ACROSS MO/IL WHICH REMAINS IN A MODERATE TO SEVERE DROUGHT. KANOFSKY && .AVIATION... ISSUED AT 1235 PM CDT FRI JUL 13 2012 UPPER LEVEL SYSTEM IS GENERATING SCATTERED STORMS ACROSS NORTHEAST MISSOURI/WEST CENTRAL ILLINOIS. SOME ISOLATED SHOWERS ARE POPPING UP ON RADAR AS FAR SOUTH AS CENTRAL MISSOURI AT THIS TIME AS WELL. THINK STORMS WILL INCREASE IN COVERAGE THIS AFTERNOON ACROSS CENTRAL AND NORTHEAST MISSOURI AS WELL AS WEST CENTRAL ILLINOIS...PRODUCING OCCASIONAL DOWN BURSTS WITH GUSTS TO 30-40KTS AND ISOLATED POCKETS OF IFR IN HEAVY RAIN. ELSEWHERE...ISOLATED SHOWERS OR THUNDERSTORMS WILL BE POSSIBLE. VFR FLIGHT CONDITIONS WILL PREVAIL OTHERWISE. SPECIFICS FOR KSTL... UPPER LEVEL SYSTEM IS PRODDING THUNDERSTORMS NORTHWEST OF THE TERMINAL THIS AFTERNOON. CAN`T TOTALLY RULE OUT A THUNDERSTORM AT LAMBERT...ESPECIALLY LATER IN THE AFTERNOON/EARLY EVENING. HOWEVER...CONFIDENCE IS NOT HIGH ENOUGH TO INCLUDE IN THE TAF AT THIS TIME. OTHERWISE...VFR FLIGHT CONDITIONS ARE EXPECTED TO PREVAIL. THERE WILL BE ANOTHER CHANCE FOR STORMS SATURDAY AFTERNOON. CARNEY && .LSX WATCHES/WARNINGS/ADVISORIES... MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
253 PM CDT FRI JUL 13 2012 .SHORT TERM... ISSUED AT 248 PM CDT FRI JUL 13 2012 (TONIGHT) SCATTERED CONVECTION HAS DEVELOPED ACROSS THE NWRN HALF OF THE CWA AHEAD OF A PV ANOMALY THAT WAS LOCATED OVER IA PER WATER VAPOR IMAGERY AND RAP 1.5 PVU FIELDS. MAINLY PULSE-TYPE THUNDERSTORMS ARE EXPECTED DUE TO WEAK SHEAR COMBINED WITH LITTLE CINH AND A FEW THOUSAND J/KG OF CAPE. DRY SUBCLOUD LAYER AND A WELL-MIXED BOUNDARY LAYER WILL ONCE AGAIN SUPPORT OCCASIONAL DOWNBURSTS WHEN THE CORES OF THE STRONGEST STORMS COLLAPSE HOWEVER WIDESPREAD SEVERE WEATHER IS NOT EXPECTED AT THIS TIME. PCPN COVERAGE SHOULD DIMINISH LATER THIS EVENING WITH THE LOSS OF DAYTIME HEATING HOWEVER A FEW AREAS OF ELEVATED CONVECTION MIGHT CONTINUE TO PERCOLATE OVERNIGHT AS THE SHORTWAVE MOVES INTO NRN MO. KANOFSKY/CARNEY && .LONG TERM... ISSUED AT 248 PM CDT FRI JUL 13 2012 (TOMORROW THROUGH NEXT THURSDAY) VORT MAX MOVING ACROSS THE UPPER MIDWEST AND ITS ASSOCIATED SFC TROF WILL PROVIDE BOTH A SOURCE OF LARGE SCALE LIFT AND A LOW LEVEL FOCUSING MECHANISM FOR SCT TSRA/SHRA TOMORROW. GENERALLY PULSE-TYPE THUNDERSTORMS ARE EXPECTED DUE TO WEAK SHEAR. ISOLATED DIURNAL PCPN MAY REDEVELOP AND LINGER ACROSS THE SERN HALF OF THE CWA ON SUN AND MON AS THE TROF SETTLES SEWD AND THE ELONGATED VORTICITY AXIS SHEARS OUT. A GRADUAL WARMING TREND IS EXPECTED OVER THE NEXT SEVERAL DAYS AS AN UPPER LEVEL RIDGE BUILDS EWD. H85 TEMPERATURES OF 20-24 DEG C WOULD SUPPORT AFTN HIGHS RANGING FROM THE MID 90S TO NEAR THE CENTURY MARK. THE CENTRAL REGION ALLBLEND INITIALIZATION REMAINS CONTAMINATED BY INCORRECT GFS OUTPUT /NCEP STAFF CONTINUE TO TROUBLESHOOT BUT HAVE NOT YET IDENTIFIED THE SOURCE OF THE PROBLEM/ THEREFORE I DEVIATED SIGNIFICANTLY FROM THE RECOMMENDED INITIALIZATION TO REDUCE POPS AND RAISE TEMPS ON DAYS 4-7. A WEAK SFC FRONT WILL APPROACH THE CWA ON WED/THU AND MOISTURE POOLING AHEAD OF THE FRONT COULD DRIVE HEAT INDEX READINGS OVER 105 DEG F IN SOME AREAS. ISOLATED TO SCATTERED THUNDERSTORMS WILL BE POSSIBLE THROUGH THE EXTENDED PD HOWEVER THERE ARE NO STRONG SIGNALS TO SUPPORT HIGHER THAN SCHC POPS ACROSS MO/IL WHICH REMAINS IN A MODERATE TO SEVERE DROUGHT. KANOFSKY && .AVIATION... ISSUED AT 1235 PM CDT FRI JUL 13 2012 UPPER LEVEL SYSTEM IS GENERATING SCATTERED STORMS ACROSS NORTHEAST MISSOURI/WEST CENTRAL ILLINOIS. SOME ISOLATED SHOWERS ARE POPPING UP ON RADAR AS FAR SOUTH AS CENTRAL MISSOURI AT THIS TIME AS WELL. THINK STORMS WILL INCREASE IN COVERAGE THIS AFTERNOON ACROSS CENTRAL AND NORTHEAST MISSOURI AS WELL AS WEST CENTRAL ILLINOIS...PRODUCING OCCASIONAL DOWN BURSTS WITH GUSTS TO 30-40KTS AND ISOLATED POCKETS OF IFR IN HEAVY RAIN. ELSEWHERE...ISOLATED SHOWERS OR THUNDERSTORMS WILL BE POSSIBLE. VFR FLIGHT CONDITIONS WILL PREVAIL OTHERWISE. SPECIFICS FOR KSTL... UPPER LEVEL SYSTEM IS PRODDING THUNDERSTORMS NORTHWEST OF THE TERMINAL THIS AFTERNOON. CAN`T TOTALLY RULE OUT A THUNDERSTORM AT LAMBERT...ESPECIALLY LATER IN THE AFTERNOON/EARLY EVENING. HOWEVER...CONFIDENCE IS NOT HIGH ENOUGH TO INCLUDE IN THE TAF AT THIS TIME. OTHERWISE...VFR FLIGHT CONDITIONS ARE EXPECTED TO PREVAIL. THERE WILL BE ANOTHER CHANCE FOR STORMS SATURDAY AFTERNOON. CARNEY && .LSX WATCHES/WARNINGS/ADVISORIES... MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1107 AM EDT FRI JUL 13 2012 .SYNOPSIS... INCREASING MOISTURE WILL LEAD TO ISOLATED TO SCATTERED SHOWERS AND PERHAPS A THUNDERSTORM THIS AFTERNOON INTO EVENING...SOUTH OF THE NEW YORK THRUWAY. MORE SIGNIFICANT MOISTURE WILL BEGIN TO RETURN OVER THE WEEKEND WITH AN INCREASING CHANCE OF RAIN AND THUNDERSTORMS...ESPECIALLY SATURDAY NIGHT INTO SUNDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 1045 AM UPDATE... SOME MID TO HIGH LEVEL CLOUDS STREAMING INTO THE SOUTHERN PORTION OF THE CWA AT THIS TIME. WATER VAPOR IMAGERY SHOWS HIGHER MOISTURE VALUES ACROSS THE SOUTHERN AND CENTRAL CWA WITH DRY AIR HOLDING ON ALONG AND NORTH OF THE THRUWAY. FORECAST PW AT VALUES ARE MUCH HIGHER ACROSS NE PA AND THE SOUTHERN TIER OF NY WITH VALUES APPROACHING 1.5 INCHES COMPARED TO AROUND .75 OF AN INCH ACROSS ONEIDA COUNTY. ADDED CHANCE POPS FOR SHOWERS AND T`STORMS FOR THE CENTRAL ZONES THIS AFTERNOON AND EVENING. EXPECTING AREAS ALONG AND NORTH OF THE THRUWAY TO REMAIN DRY TODAY. WE ARE NOT EXPECTING ANY SEVERE THUNDERSTORMS TODAY DUE TO NARROW CAPES AND VERY LITTLE FLOW THROUGHOUT THE COLUMN...HOWEVER ANY STORMS THAT DO FORM WILL BE SLOW MOVERS AND THEREFORE ADDED THE MENTION OF LOCALIZED HEAVY RAINFALL IN THE HWO. AS FOR TEMPERATURES, WE HAVE RAISED OUR EXPECTED MAXES A DEGREE OR TWO INTO THE LOW TO MID 90S FOR LOWER ELEVATIONS OF THE NORTHERN AND CENTRAL CWA WHERE A LITTLE BIT MORE SUN WILL FILTER THROUGH THE HIGH CLOUDS. HIGHS SHOULD BE MAINLY IN THE MID TO UPPER 80S ACROSS NE PA WITH MORE CLOUDS. PREVIOUS DISCUSSION... THE WEATHER SHOULD REMAIN QUIET FOR THE REMAINDER OF THE MORNING. MODELS ARE INDICATING A MODERATE AREA OF 500MB VORT ADV MOVING THROUGH NEPA AND THE SOUTHERN TIER THIS AFTERNOON. THERE WILL BE MID AND UPPER LEVEL MOISTURE AVAILABLE THIS AFTERNOON AS WELL. HOWEVER, THIS IS MOVING AROUND A FAIRLY STRONG UPPER LEVEL RIDGE, WHICH SHOULD INHIBIT SOME OF THE DEVELOPMENT. ALSO, MODELS ARE DIFFERING WITH COVERAGE AND TIMING OF ANY CONVECTION THIS AFTERNOON. HAVE INCREASED COVERAGE OF POP, BUT KEPT THE ACTUAL POP VALUE IN THE ISOLD RANGE. THERE IS PLENTY OF CAPE AROUND TODAY, WITH THE NAM COMING IN AT AROUND 1600 JOULES OVER THE SOUTHERN TIER TODAY. THE GFS IS NOT SO GENEROUS WITH THE CAPE, BRINGING LESS THAN 100 JOULES TO THE SOUTHERN TIER, BUT IS SHOWING ABOUT 600 JOULES IN THE SYRACUSE AREA. BUT, BEST DYNAMICS LOOK TO BE SOUTH OF THE GFS CAPE FORECAST LOCATION. WENT MORE IN LINE WITH THE NAM FOR ANY CONVECTIVE DEVELOPMENT TODAY, ALTHOUGH STILL KEPT THE AREA FAIRLY BROAD. THE HRRR IS ALSO SHOWING SOME WEAK DEVELOPMENT ACROSS THE CENTRAL AND SOUTHERN PORTIONS OF THE CWA THIS AFTERNOON. AS THE DAY PROGRESSES, MBE VALUES ARE FAIRLY LOW, SO SHOWERS MAY NOT MOVE VERY FAST, AS WAS THE CASE YESTERDAY. ALSO, PWATS LOOK TO RISE ABOVE AN INCH LATER TODAY, WHICH BOTH SUPPORT THE NOTION OF POSSIBLE HEAVY RAIN THAT DOES NOT MOVE VERY MUCH, IF ANY DO DEVELOP. && .SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/... MODELS ARE IN AGREEMENT WITH THE RETURN OF ABUNDANT MOISTURE THIS WEEKEND. THIS WILL BE COMING UP FROM THE SOUTH, AROUND THE BERMUDA HIGH. THEY ALSO INDICATE SEVERAL WEAK SHORT WAVES WILL MOVE THROUGH THE UPPER LEVEL FLOW. THESE WILL COMBINE WITH THE MOISTURE AND DAYTIME HEATING TO ALLOW THE DEVELOPMENT OF SHOWERS AND THUNDERSTORMS THIS WEEKEND. CHANCES OF PRECIPITATION RISE THROUGH THE WEEKEND. BY SUNDAY, THE UPPER LEVEL RIDGE BEGINS TO BREAK DOWN AND A SFC TROUGH MOVES ACROSS THE AREA. THIS WILL ALLOW SCT SHOWERS AND STORMS THROUGHOUT THE DAY SUNDAY. CURRENTLY WENT WITH 50 POPS ACROSS THE BOARD SUNDAY, BUT WOULD NOT BE SURPRISED IF HIGHER POPS ARE NEEDED. THEN, AN UPPER LEVEL TROUGH FOLLOWS THE SFC TROUGH, WHICH WILL PROLONG THE SHOWERS OVER THE CWA INTO SUNDAY NIGHT. THERE IS SOME SMALL TIMING DIFFERENCES, BUT NOT ENOUGH TO MAKE A SIGNIFICANT DIFFERENCE IN THE FORECAST. THERE IS THE POTENTIAL, HOWEVER, FOR SOME HEAVY RAIN WITH ANY STORMS THAT DO DEVELOP. CURRENT QPF TOTALS ARE AROUND A HALF INCH FROM EARLY SUNDAY MORNING THROUGH SUNDAY AFTERNOON. SOME MODELS ARE INDICATING THAT AROUND AND INCH TO AN INCH AND A QUARTER ARE POSSIBLE THOUGH. OF COURSE, THIS COULD VERY WELL CHANGE, EITHER MORE OR LESS RAIN, OVER THE NEXT COUPLE OF MODELS RUNS. && .LONG TERM /MONDAY THROUGH THURSDAY/... THE EXTENDED PERIOD WILL REMAIN WARM AND HUMID THROUGH WEDNESDAY WITH A SOUTHWEST FLOW ACROSS THE REGION DUE TO RETURN FLOW FROM HIGH PRESSURE OFF THE MID ATLANTIC COAST. SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE JUST ABOUT ANYTIME IN THIS TYPE OF PATTERN WITH THE MAIN CHALLENGE BEING WHETHER ANY PERIODS OF ENHANCED ACTIVITY CAN BE TIMED. COVERAGE OF STORMS IN THE ABSENCE OF SIGNIFICANT DYNAMICAL FORCING WILL PROBABLY BE JUST 20 OR 30 PERCENT. LATEST GFS/ECMWF GUIDANCE INDICATES THAT THE BEST CHANCE FOR STORMS WILL BE ON WEDNESDAY AS A COLD FRONT DROPS THROUGH THE REGION. A COOLER/DRIER AIR MASS WILL FOLLOW THE FRONT ON THURSDAY. TEMPERATURES WILL CONTINUE TO AVERAGE ABOVE NORMAL...WITH HIGHS MAINLY IN THE MID 80S TO LOWER 90S AND LOWS IN THE 60S. HIGHS ON THURSDAY WILL BE COOLER GENERALLY IN THE LOWER TO MIDDLE 80S. && .AVIATION /15Z FRIDAY THROUGH TUESDAY/... VFR CONDITIONS ARE EXPECTED THROUGH THIS TAF PERIOD AS SFC HIGH PRESSURE REMAINS OVER THE AREA. MID LEVEL MOISTURE AND A WEAK UPPER LEVEL DISTURBANCE WILL MAKE FOR SCT/BKN CLOUDS AROUND 6-7K FT TODAY. ISOLATED CONVECTION WILL OCCUR THIS AFTERNOON ACROSS NE PA AND THE SOUTHERN TIER BUT NOT INCLUDED IN TAFS DUE TO VERY LIMITED AREAL COVERAGE. OVERNIGHT, AS THIS WAVE PASSES SKIES SHOULD SCATTER OUT WITH THE POSSIBILITY OF MVFR VSBYS AT KELM TOWARD DAYBREAK DUE TO BR. LIGHT AND VARIABLE WINDS BECOMING W/SW BY LATE MORNING AROUND 5 KNOTS THEN LIGHT AGAIN TONIGHT. OUTLOOK... SAT/SUN/MON...GENERALLY VFR. CHC FOR SCT MVFR IN SHWRS/TSTMS...MAINLY IN THE AFTN/EVNG. TUE...VFR. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...SLI/MDP NEAR TERM...MDP/SLI/MM SHORT TERM...SLI LONG TERM...MSE/RRM AVIATION...RRM
AREA FORECAST DISCUSSION
NWS BUFFALO NY
1003 AM EDT FRI JUL 13 2012 .SYNOPSIS... HIGH PRESSURE WILL LINGER ACROSS THE MID ATLANTIC STATES AND NEW ENGLAND TODAY...THEN WILL SLIDE OFF THE EAST COAST DURING THE UPCOMING WEEKEND. THIS FEATURE WILL CONTINUE TO CIRCULATE VERY WARM AND INCREASINGLY MOIST AIR ACROSS THE REGION...RESULTING IN A CONTINUATION OF ABOVE NORMAL TEMPERATURES...ALONG WITH SLOWLY INCREASING CHANCES FOR SHOWERS AND THUNDERSTORMS THROUGH THE WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... DEWPOINTS FROM KBUF TO KROC HAVE INCREASED 5-10F OVER THE PAST 24 HOURS WHILE DEWPOINTS WELL INLAND HAVE NOT CHANGED MUCH. THE 12Z KBUF SOUNDING ALSO SHOWS A BIT MORE AVAILABLE LOW LEVEL MOISTURE WITH PRECIPITABLE WATER CREEPING UP PAST THE ONE INCH MARK. WITH MORE AVAILABLE LOW LEVEL MOISTURE...FORECAST CAPES WITH TEMPERATURES NEAR 90 YIELD VALUES NEAR 1000J/KG. NUMEROUS RUNS OF THE HRRR AND SOME OF THE HIGHER RES MODELS FROM SPC SHOW CONVECTION THIS AFTERNOON ALONG LAKE BREEZES. CURRENT FORECAST PORTRAYS THIS WELL WITH A 20-30 PERCENT CHANCE OF TSTORM DEVELOPMENT LATER THIS AFTERNOON GENERALLY INLAND...WITH THE HIGHEST THREAT ALONG THE LAKE ERIE BREEZE AND INTO THE HIGHER TERRAIN IN THE SOUTHERN TIER. WILL LEAVE FORECAST ALONE ALTHOUGH WILL ADD THE WORD INLAND TO THE WORDED ZFP. GRIDS LOOK GREAT. AS WAS THE CASE YESTERDAY...THE VERY WEAK FLOW THROUGHOUT THE DEPTH OF THE TROPOSPHERE WILL RESULT IN A VERY SLOW MOVEMENT TO ANY SHOWERS AND STORMS THAT DO DEVELOP...RESULTING IN A POTENTIAL FOR HIGHLY LOCALIZED AREAS OF HEAVY RAINFALL. EXPECT ANY CONVECTION THAT FORMS THIS AFTERNOON TO ONCE AGAIN LINGER INTO EARLY THIS EVENING...THEN SLOWLY DIE OUT AFTER SUNSET WITH THE LOSS OF HEATING. THIS SHOULD RESULT IN A RETURN OF MAINLY DRY WEATHER FOR THE SECOND HALF OF THE UPCOMING NIGHT. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... CONDITIONS STILL LOOK FAVORABLE FOR SOME BADLY NEEDED RAINFALL DURING THIS PERIOD...ESPECIALLY ON SUNDAY WHEN AN APPROACHING UPPER LEVEL TROUGH WILL INTERACT WITH ABUNDANT LOW LEVEL MOISTURE THAT WILL BE IN PLACE. ON SATURDAY...THE MODELS ARE STILL SHOWING A VARIETY OF SOLUTIONS REGARDING THE THE TIMING AND LOCATION OF A SERIES OF SHORTWAVES THAT WILL BE MOVING NORTH FROM THE OHIO VALLEY. THEREFORE...WILL MAINTAIN CONTINUITY AND INDICATE A GRADUAL SOUTH TO NORTH INCREASE IN CHANCE POPS AS THE DEEP LAYERED SOUTHERLY FLOW TRANSPORTS INCREASING MOISTURE NORTH TOWARD THE LOWER LAKES. AS THE UPPER LEVEL TROUGH AND EMBEDDED SHORT WAVE HEAD EAST TOWARD THE LOWER LAKES SATURDAY NIGHT AND SUNDAY...IT WILL INTERCEPT MOISTURE THAT WILL BE STREAMING NORTH FROM THE OHIO VALLEY. WHILE THIS PERIOD LOOKS TO BE OUR BEST CHANCE TO RECEIVE SOME MEASURABLE PCPN...IT MUST BE EMPHASIZED THAT THE PRECIP MODE WILL BE CONVECTIVE...MEANING SOME AREAS HAVE THE POTENTIAL TO RECEIVE A CONSIDERABLE AMOUNT OF RAIN IN A SHORT AMOUNT OF TIME WHILE OTHER AREAS RECEIVE NOTHING. THIS IS NOT THE KIND STEADY RAIN OVER AN EXTENDED PERIOD OR AREA THAT WE TYPICALLY WANT TO MITIGATE DROUGHT CONDITIONS. HOWEVER...THE LATEST CORFIDI VECTOR ANALYSIS DOES HINT AT THE POSSIBILITY OF BACK BUILDING CELLS SATURDAY NIGHT INTO SUNDAY MORNING AS A MODEST LOW LEVEL JET TRACKS EAST ACROSS WESTERN AND CENTRAL NEW YORK. IF THIS COMES TO FRUITION...MORE BENEFICIAL RAINFALL MAY BE POSSIBLE. THERE IS HIGH CONFIDENCE THAT THIS WILL BE A RATHER WARM AND HUMID PERIOD. WITH DEWPOINTS EXPECTED TO BE IN THE MID AND UPPER 60S...THERE WILL BE LITTLE RELIEF FROM THE UNCOMFORTABLE CONDITIONS SATURDAY NIGHT. OVERNIGHT LOWS WILL RANGE FROM THE MID AND UPPER 60S ACROSS THE SOUTHERN TIER TO THE LOWER 70S ALONG THE LAKE PLAINS. HIGH TEMPERATURES ON SATURDAY AND SUNDAY WILL RANGE THROUGH THE 80S...ALTHOUGH SUNDAY WILL BE SLIGHTLY COOLER DUE TO THE ANTICIPATED INCREASE IN CLOUD COVER AND BETTER CHANCE FOR RAIN. AS THE UPPER LEVEL TROUGH PUSHES EAST INTO NEW ENGLAND SUNDAY NIGHT...EXPECT ANY ONGOING CONVECTION TO TAPER OFF GRADUALLY FROM WEST TO EAST. && .LONG TERM /MONDAY THROUGH THURSDAY/... EXPECT WARM AND HUMID WEATHER TO CONTINUE THROUGH THE FIRST PORTION OF NEXT WEEK AS THE AREA REMAINS ON THE NORTHERN FRINGE OF RETURN FLOW AROUND THE BERMUDA HIGH ANCHORED OFF OF THE SOUTHEAST U.S. COAST. WITH 850MB TEMPS HOLDING AROUND +18C...AND POSSIBLY WARMER...EXPECT AFTERNOON HIGHS TO RUN IN THE UPPER 80S AND POSSIBLY THE LOWER 90S. WITH PLENTY OF MOISTURE STILL IN PLACE...AFTERNOON CONVECTION...MAINLY ALONG LAKE BREEZE BOUNDARIES...CANNOT BE RULED OUT. GIVEN THE WARM AND MOIST BOUNDARY LAYER...WIDESPREAD CONVECTION WILL LIKELY BE LIMITED BY WEAK MID-LEVEL LAPSE RATES. THERE IS ALSO A POSSIBILITY THAT CONVECTION MAY BE TRIGGERED OR ENHANCED BY WEAK SHORTWAVES MOVING THROUGH THE PROGRESSIVE FLOW ALOFT. MODEL AGREEMENT IS CURRENTLY SURPRISINGLY GOOD IN SUGGESTING A SIGNIFICANT CHANGE BY THE MIDDLE OF NEXT WEEK. NORTHERN STEAM SHORTWAVE ENERGY IS CURRENTLY PROGGED TO PHASE WITH AN UPPER LOW TRACKING ACROSS NORTHERN CANADA...SWINGING A STRONG SHORTWAVE TROUGH ACROSS THE GREAT LAKES WEDNESDAY. AN ACCOMPANYING COLD FRONT IS CURRENTLY PREDICTED TO SWING ACROSS THE LOWER GREAT LAKES SOMETIME LATE WEDNESDAY...RESULTING IN SIGNIFICANTLY COOLER AND DRIER WEATHER FOR THE LATTER HALF OF NEXT WEEK. && .AVIATION /14Z FRIDAY THROUGH TUESDAY/... TODAY...EXPECT VFR CONDITIONS...WITH DIURNAL CU ALSO EXPECTED TO REDEVELOP WITH DIURNAL HEATING. WITH INCREASING DAYTIME INSTABILITY...ISOLATED TO SCATTERED SHOWERS AND STORMS WILL ONCE AGAIN REDEVELOP ALONG FAVORED LAKE BREEZE CONVERGENCE ZONES...TERRAIN FEATURES...AND LEFTOVER OUTFLOW BOUNDARIES FROM CONVECTION YESTERDAY. THE BEST AREAL COVERAGE OF THIS IS MOST LIKELY TO BE FROM THE WESTERN SOUTHERN TIER NORTHEASTWARD ACROSS THE FINGER LAKES...WITH MORE SPARSE COVERAGE MORE LIKELY FURTHER TO THE NORTH AND WEST FROM KBUF EASTWARD TO KROC/KFZY. HAVE THEREFORE CONTINUED WITH A MENTION OF VCSH IN THE KJHW TAF FOR NOW...WITH NO MENTION ELSEWHERE GIVEN THE EXPECTED SPARSER COVERAGE. TONIGHT...ANY CONVECTION SHOULD AGAIN TEND TO SLOWLY WIND DOWN WITH THE LOSS OF HEATING THIS EVENING...LEAVING BEHIND VFR CONDITIONS UNDER JUST SOME SCATTERED MID CLOUDS...ALONG WITH SOME CIRRUS. OUTLOOK... SATURDAY AND SUNDAY...AREAS OF MVFR IN SCATTERED -SHRA/-TSRA. MONDAY AND TUESDAY...MAINLY VFR WITH THE CHANCE OF A SHOWER OR THUNDERSTORM. && .MARINE... HIGH PRESSURE WILL REMAIN ACROSS THE LOWER GREAT LAKES REGION TODAY...BEFORE DRIFTING OFF THE EAST COAST THIS WEEKEND. THIS FEATURE WILL MAINTAIN GENERALLY LIGHT WINDS AND MINIMAL WAVES THROUGH THE WEEKEND. FAIR WEATHER WILL ALSO GENERALLY CONTINUE THROUGH TODAY...WITH CHANCES FOR SHOWERS AND THUNDERSTORMS THEN INCREASING DURING THE COURSE OF THE WEEKEND. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...NONE. MARINE...NONE. && $$ SYNOPSIS...JJR NEAR TERM...JJR/ZAFF SHORT TERM...TJP LONG TERM...TJP/WOOD AVIATION...JJR MARINE...JJR
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
558 AM EDT FRI JUL 13 2012 .SYNOPSIS... MOSTLY QUIET WEATHER TODAY...WITH POSSIBLY AN ISOLATED SHOWER OR EVEN A THUNDERSTORM LATE THIS AFTERNOON AS AN UPPER LEVEL RIDGE HOLDS ON FOR ON MORE DAY. MOISTURE WILL BEGIN TO RETURN ON SATURDAY WITH AN INCREASING CHANCE OF RAIN AND THUNDERSTORMS THROUGH THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... THE WEATHER SHOULD REMAIN QUIET FOR THE REMAINDER OF THE MORNING. MODELS ARE INDICATING A MODERATE AREA OF 500MB VORT ADV MOVING THROUGH NEPA AND THE SOUTHERN TIER THIS AFTERNOON. THERE WILL BE MID AND UPPER LEVEL MOISTURE AVAILABLE THIS AFTERNOON AS WELL. HOWEVER, THIS IS MOVING AROUND A FAIRLY STRONG UPPER LEVEL RIDGE, WHICH SHOULD INHIBIT SOME OF THE DEVELOPMENT. ALSO, MODELS ARE DIFFERING WITH COVERAGE AND TIMING OF ANY CONVECTION THIS AFTERNOON. HAVE INCREASED COVERAGE OF POP, BUT KEPT THE ACTUAL POP VALUE IN THE ISOLD RANGE. THERE IS PLENTY OF CAPE AROUND TODAY, WITH THE NAM COMING IN AT AROUND 1600 JOULES OVER THE SOUTHERN TIER TODAY. THE GFS IS NOT SO GENEROUS WITH THE CAPE, BRINGING LESS THAN 100 JOULES TO THE SOUTHERN TIER, BUT IS SHOWING ABOUT 600 JOULES IN THE SYRACUSE AREA. BUT, BEST DYNAMICS LOOK TO BE SOUTH OF THE GFS CAPE FORECASTED LOCATION. WENT MORE IN LINE WITH THE NAM FOR ANY CONVECTIVE DEVELOPMENT TODAY, ALTHOUGH STILL KEPT THE AREA FAIRLY BROAD. THE HRRR IS ALSO SHOWING SOME WEAK DEVELOPMENT ACROSS THE CENTRAL AND SOUTHERN PORTIONS OF THE CWA THIS AFTERNOON. AS THE DAY PROGRESSES, MBE VALUES ARE FAIRLY LOW, SO SHOWERS MAY NOT MOVE VERY FAST, AS WAS THE CASE YESTERDAY. ALSO, PWATS LOOK TO RISE ABOVE AN INCH LATER TODAY, WHICH BOTH SUPPORT THE NOTION OF POSSIBLE HEAVY RAIN THAT DOES NOT MOVE VERY MUCH, IF ANY DO DEVELOP. && .SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/... MODELS ARE IN AGREEMENT WITH THE RETURN OF ABUNDANT MOISTURE THIS WEEKEND. THIS WILL BE COMING UP FROM THE SOUTH, AROUND THE BERMUDA HIGH. THEY ALSO INDICATE SEVERAL WEAK SHORT WAVES WILL MOVE THROUGH THE UPPER LEVEL FLOW. THESE WILL COMBINE WITH THE MOISTURE AND DAYTIME HEATING TO ALLOW THE DEVELOPMENT OF SHOWERS AND THUNDERSTORMS THIS WEEKEND. CHANCES OF PRECIPITATION RISE THROUGH THE WEEKEND. BY SUNDAY, THE UPPER LEVEL RIDGE BEGINS TO BREAK DOWN AND A SFC TROUGH MOVES ACROSS THE AREA. THIS WILL ALLOW SCT SHOWERS AND STORMS THROUGHOUT THE DAY SUNDAY. CURRENTLY WENT WITH 50 POPS ACROSS THE BOARD SUNDAY, BUT WOULD NOT BE SURPRISED IF HIGHER POPS ARE NEEDED. THEN, AN UPPER LEVEL TROUGH FOLLOWS THE SFC TROUGH, WHICH WILL PROLONG THE SHOWERS OVER THE CWA INTO SUNDAY NIGHT. THERE IS SOME SMALL TIMING DIFFERENCES, BUT NOT ENOUGH TO MAKE A SIGNIFICANT DIFFERENCE IN THE FORECAST. THERE IS THE POTENTIAL, HOWEVER, FOR SOME HEAVY RAIN WITH ANY STORMS THAT DO DEVELOP. CURRENT QPF TOTALS ARE AROUND A HALF INCH FROM EARLY SUNDAY MORNING THROUGH SUNDAY AFTERNOON. SOME MODELS ARE INDICATING THAT AROUND AND INCH TO AN INCH AND A QUARTER ARE POSSIBLE THOUGH. OF COURSE, THIS COULD VERY WELL CHANGE, EITHER MORE OR LESS RAIN, OVER THE NEXT COUPLE OF MODELS RUNS. && .LONG TERM /MONDAY THROUGH THURSDAY/... THE EXTENDED PERIOD WILL REMAIN WARM AND HUMID THROUGH WEDNESDAY WITH A SOUTHWEST FLOW ACROSS THE REGION DUE TO RETURN FLOW FROM HIGH PRESSURE OFF THE MID ATLANTIC COAST. SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE JUST ABOUT ANYTIME IN THIS TYPE OF PATTERN WITH THE MAIN CHALLENGE BEING WHETHER ANY PERIODS OF ENHANCED ACTIVITY CAN BE TIMED. COVERAGE OF STORMS IN THE ABSENCE OF SIGNIFICANT DYNAMICAL FORCING WILL PROBABLY BE JUST 20 OR 30 PERCENT. LATEST GFS/ECMWF GUIDANCE INDICATES THAT THE BEST CHANCE FOR STORMS WILL BE ON WEDNESDAY AS A COLD FRONT DROPS THROUGH THE REGION. A COOLER/DRIER AIR MASS WILL FOLLOW THE FRONT ON THURSDAY. TEMPERATURES WILL CONTINUE TO AVERAGE ABOVE NORMAL...WITH HIGHS MAINLY IN THE MID 80S TO LOWER 90S AND LOWS IN THE 60S. HIGHS ON THURSDAY WILL BE COOLER GENERALLY IN THE LOWER TO MIDDLE 80S. && .AVIATION /10Z FRIDAY THROUGH TUESDAY/... VFR CONDITIONS ARE EXPECTED THROUGH THIS TAF PERIOD AS SFC HIGH PRESSURE REMAINS OVER THE AREA. MID LEVEL MOISTURE AND A WEAK UPPER LEVEL DISTURBANCE WILL MAKE FOR SCT/BKN CLOUDS AROUND 6-7K FT TODAY. ISOLATED CONVECTION WILL OCCUR THIS AFTERNOON ACROSS NE PA AND THE SOUTHERN TIER BUT NOT INCLUDED IN TAFS DUE TO VERY LIMITED AREAL COVERAGE. OVERNIGHT, AS THIS WAVE PASSES SKIES SHOULD SCATTER OUT WITH THE POSSIBILITY OF MVFR VSBYS AT KELM TOWARD DAYBREAK DUE TO BR. LIGHT AND VARIABLE WINDS BECOMING W/SW BY LATE MORNING AROUND 5 KNOTS THEN LIGHT AGAIN TONIGHT. OUTLOOK... SAT/SUN/MON...GENERALLY VFR. CHC FOR SCT MVFR IN SHWRS/TSTMS...MAINLY IN THE AFTN/EVNG. TUE...VFR. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...SLI NEAR TERM...SLI SHORT TERM...SLI LONG TERM...MSE/RRM AVIATION...RRM
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
440 AM EDT FRI JUL 13 2012 .SYNOPSIS... MOSTLY QUIET WEATHER TODAY...WITH POSSIBLY AN ISOLATED SHOWER OR EVEN A THUNDERSTORM LATE THIS AFTERNOON AS AN UPPER LEVEL RIDGE HOLDS ON FOR ON MORE DAY. MOISTURE WILL BEGIN TO RETURN ON SATURDAY WITH AN INCREASING CHANCE OF RAIN AND THUNDERSTORMS THROUGH THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... THE WEATHER SHOULD REMAIN QUIET FOR THE REMAINDER OF THE MORNING. MODELS ARE INDICATING A MODERATE AREA OF 500MB VORT ADV MOVING THROUGH NEPA AND THE SOUTHERN TIER THIS AFTERNOON. THERE WILL BE MID AND UPPER LEVEL MOISTURE AVAILABLE THIS AFTERNOON AS WELL. HOWEVER, THIS IS MOVING AROUND A FAIRLY STRONG UPPER LEVEL RIDGE, WHICH SHOULD INHIBIT SOME OF THE DEVELOPMENT. ALSO, MODELS ARE DIFFERING WITH COVERAGE AND TIMING OF ANY CONVECTION THIS AFTERNOON. HAVE INCREASED COVERAGE OF POP, BUT KEPT THE ACTUAL POP VALUE IN THE ISOLD RANGE. THERE IS PLENTY OF CAPE AROUND TODAY, WITH THE NAM COMING IN AT AROUND 1600 JOULES OVER THE SOUTHERN TIER TODAY. THE GFS IS NOT SO GENEROUS WITH THE CAPE, BRINGING LESS THAN 100 JOULES TO THE SOUTHERN TIER, BUT IS SHOWING ABOUT 600 JOULES IN THE SYRACUSE AREA. BUT, BEST DYNAMICS LOOK TO BE SOUTH OF THE GFS CAPE FORECASTED LOCATION. WENT MORE IN LINE WITH THE NAM FOR ANY CONVECTIVE DEVELOPMENT TODAY, ALTHOUGH STILL KEPT THE AREA FAIRLY BROAD. THE HRRR IS ALSO SHOWING SOME WEAK DEVELOPMENT ACROSS THE CENTRAL AND SOUTHERN PORTIONS OF THE CWA THIS AFTERNOON. AS THE DAY PROGRESSES, MBE VALUES ARE FAIRLY LOW, SO SHOWERS MAY NOT MOVE VERY FAST, AS WAS THE CASE YESTERDAY. ALSO, PWATS LOOK TO RISE ABOVE AN INCH LATER TODAY, WHICH BOTH SUPPORT THE NOTION OF POSSIBLE HEAVY RAIN THAT DOES NOT MOVE VERY MUCH, IF ANY DO DEVELOP. && .SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/... MODELS ARE IN AGREEMENT WITH THE RETURN OF ABUNDANT MOISTURE THIS WEEKEND. THIS WILL BE COMING UP FROM THE SOUTH, AROUND THE BERMUDA HIGH. THEY ALSO INDICATE SEVERAL WEAK SHORT WAVES WILL MOVE THROUGH THE UPPER LEVEL FLOW. THESE WILL COMBINE WITH THE MOISTURE AND DAYTIME HEATING TO ALLOW THE DEVELOPMENT OF SHOWERS AND THUNDERSTORMS THIS WEEKEND. CHANCES OF PRECIPITATION RISE THROUGH THE WEEKEND. BY SUNDAY, THE UPPER LEVEL RIDGE BEGINS TO BREAK DOWN AND A SFC TROUGH MOVES ACROSS THE AREA. THIS WILL ALLOW SCT SHOWERS AND STORMS THROUGHOUT THE DAY SUNDAY. CURRENTLY WENT WITH 50 POPS ACROSS THE BOARD SUNDAY, BUT WOULD NOT BE SURPRISED IF HIGHER POPS ARE NEEDED. THEN, AN UPPER LEVEL TROUGH FOLLOWS THE SFC TROUGH, WHICH WILL PROLONG THE SHOWERS OVER THE CWA INTO SUNDAY NIGHT. THERE IS SOME SMALL TIMING DIFFERENCES, BUT NOT ENOUGH TO MAKE A SIGNIFICANT DIFFERENCE IN THE FORECAST. THERE IS THE POTENTIAL, HOWEVER, FOR SOME HEAVY RAIN WITH ANY STORMS THAT DO DEVELOP. CURRENT QPF TOTALS ARE AROUND A HALF INCH FROM EARLY SUNDAY MORNING THROUGH SUNDAY AFTERNOON. SOME MODELS ARE INDICATING THAT AROUND AND INCH TO AN INCH AND A QUARTER ARE POSSIBLE THOUGH. OF COURSE, THIS COULD VERY WELL CHANGE, EITHER MORE OR LESS RAIN, OVER THE NEXT COUPLE OF MODELS RUNS. && .LONG TERM /MONDAY THROUGH THURSDAY/... THE EXTENDED PERIOD WILL REMAIN WARM AND HUMID THROUGH WEDNESDAY WITH A SOUTHWEST FLOW ACROSS THE REGION DUE TO RETURN FLOW FROM HIGH PRESSURE OFF THE MID ATLANTIC COAST. SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE JUST ABOUT ANYTIME IN THIS TYPE OF PATTERN WITH THE MAIN CHALLENGE BEING WHETHER ANY PERIODS OF ENHANCED ACTIVITY CAN BE TIMED. COVERAGE OF STORMS IN THE ABSENCE OF SIGNIFICANT DYNAMICAL FORCING WILL PROBABLY BE JUST 20 OR 30 PERCENT. LATEST GFS/ECMWF GUIDANCE INDICATES THAT THE BEST CHANCE FOR STORMS WILL BE ON WEDNESDAY AS A COLD FRONT DROPS THROUGH THE REGION. A COOLER/DRIER AIR MASS WILL FOLLOW THE FRONT ON THURSDAY. TEMPERATURES WILL CONTINUE TO AVERAGE ABOVE NORMAL...WITH HIGHS MAINLY IN THE MID 80S TO LOWER 90S AND LOWS IN THE 60S. HIGHS ON THURSDAY WILL BE COOLER GENERALLY IN THE LOWER TO MIDDLE 80S. && .AVIATION /08Z FRIDAY THROUGH TUESDAY/... VFR CONDITIONS ARE EXPECTED THROUGH THIS TAF PERIOD AS SFC HIGH PRESSURE REMAINS OVER THE AREA. INCREASING MID LEVEL MOISTURE AND AND A WEAK MID LEVEL DISTURBANCE WILL MAKE FOR SCT/BKN CLOUDS AROUND 6-7K FT THROUGH THE PERIOD. FOG IS NOT EXPECTED AT KELM THIS MORNING DUE TO MID LEVEL CLOUDS AND A LARGE TEMP/DEW POINT SPREAD AT 05Z. ISOLATED CONVECTION WILL OCCUR THIS AFTERNOON ACROSS NE PA AND THE SOUTHERN TIER BUT NOT INCLUDED IN TAFS DUE TO VERY LIMITED AREAL COVERAGE. LIGHT AND VARIABLE WINDS BECOMING W/SW BY MID MORNING AROUND 5 KNOTS THEN LIGHT AGAIN TONIGHT. OUTLOOK... SAT/SUN/MON...GENERALLY VFR. CHC FOR SCT MVFR IN SHWRS/TSTMS...MAINLY IN THE AFTN/EVNG. TUE...VFR. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...SLI NEAR TERM...SLI SHORT TERM...SLI LONG TERM...MSE/RRM AVIATION...RRM
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1025 PM EDT SAT JUL 14 2012 .SYNOPSIS... ATLANTIC HIGH PRESSURE WILL EXTEND ACROSS THE AREA THROUGH THE MIDDLE OF NEXT WEEK. A COLD FRONT WILL APPROACH FROM THE NORTH LATE NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1030 PM SATURDAY...ASIDE FROM A FEW TWEAKS TO SKY COVER AND DEWPOINT...ALL OTHER FORECAST ELEMENTS ARE ON TRACK WITH PRIOR FORECASTS. SCATTERED SHOWERS DEVELOPING ACROSS THE GULF STREAM MAY MAKE IT TO THE BEACHES AFTER 3-4 AM ACCORDING TO LINEAR EXTRAPOLATION AND THE LATEST HRRR MODEL RUN. PREVIOUS DISCUSSION FROM 730 PM FOLLOWS... BERMUDA HIGH PRESSURE CONTINUES TO PUMP A HUMID TROPICAL AIRMASS ONSHORE IN THE LOWEST LEVELS. THERE IS A RATHER STEEP DECREASE IN MOISTURE ALOFT WITH PRECIPITABLE WATER VALUES ABOUT A HALF INCH LOWER THAN THIS TIME LAST NIGHT...MAINLY DUE TO DECREASES IN MOISTURE BETWEEN 950-400 MB. WITH LIGHT SURFACE WINDS TONIGHT AND MAINLY CLEAR SKIES LOWS SHOULD FALL INTO THE LOWER 70S AWAY FROM THE BEACHES...NEAR OR EVEN A DEGREE BELOW NORMAL FOR MOST AREAS. A FEW OF THE MARINE SHOWERS OBSERVED ON SATELLITE AND RADAR MAY WORK THEIR WAY ONSHORE FOR THE COASTAL COUNTIES LATE THIS EVENING AND OVERNIGHT...BUT ANY MEASURABLE RAIN SHOULD REMAIN ISOLATED IN NATURE. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 2 PM SATURDAY...BERMUDA RIDGE WILL EXTEND ACROSS THE EASTERN CAROLINAS AT THE BEGINNING OF THE PERIOD...WITH A SLIGHT TRANSLATION TO THE SE...AWAY FROM THE AREA DURING THE LATER PORTION OF THE PERIOD. THE SEABREEZE BOUNDARY WILL BE PRESENT...BUT PINNED CLOSER TO THE COAST MON VS SUN GIVEN 800-900 MB FLOW WILL BE MORE WESTERLY. DEVELOPING PIEDMONT TROUGH WILL BECOME RATHER PRONOUNCED MON AFTERNOON AND EVE. HIGH PRESSURE ALOFT WILL PERSIST INTO SUN...AND THEN BREAK DOWN AS WE GO INTO MON. LOW PRESSURE ALOFT...CURRENTLY SEEN ON WATER VAPOR IMAGERY NEAR 29.4 N AND 72.3 W...WILL CONTINUE TO MOVE W TOWARD THE LOWER SOUTHEAST COAST AND SOME OF THE MODELS HAVE THIS FEATURE REACHING THE COAST ON MON. AIRMASS WILL BE DRIER ON SUN AND SUBSIDENCE WILL BE STRONGER... HOWEVER...DEEP EASTERLY FLOW SHOULD ALLOW SHOWERS ACROSS THE WATERS TO REACH THE IMMEDIATE COAST WHILE OTHER SHOWERS DEVELOP ALONG THE SEABREEZE BOUNDARY AND MOVE WELL INLAND GIVEN THE EASTERLY FLOW. RAINFALL RATES SHOULD BE MUCH LOWER THAN EARLIER IN THE WEEK GIVEN THE PRESENCE OF DRIER AIR. CONVECTION SHOULD ALSO BE RATHER SHALLOW WITH A CAP DEVELOPING AROUND 10 KFT. AT THIS TIME...EXPECT CONVECTION WILL BE ISOLATED TO PERHAPS WIDELY SCATTERED WITH MOST LOCATIONS BEING RAIN FREE THROUGH THE DAY. ANY CONVECTION SHOULD END QUICKLY DURING THE EVE AND WITH DEVELOPING LAND BREEZE...EXPECT ANY SHOWERS OFFSHORE WILL NOT BE ABLE TO PUSH ON SHORE OVERNIGHT AS FLOW BECOMES WESTERLY. ON MON...AS RIDGING BREAKS DOWN...SOME CONVECTION SHOULD BE ABLE TO FORM ALONG THE STRENGTHENING PIEDMONT TROUGH AND PERHAPS THE SEABREEZE...NEAR THE COAST. PRECIPITABLE WATER VALUES BEGIN TO INCREASE AND SHOULD BE BETWEEN 1.75 AND 2 INCHES MON AFTERNOON AND EVE. STILL SOME CAPPING EVIDENT AROUND 12 KFT...SO NOT WILLING TO GO MUCH HIGHER THAN SLIGHT CHANCE/SMALL CHANCE AT THIS TIME. SHOULD UPPER LOW/TROUGH TO OUR S BE STRONGER OR FURTHER N...THAN CURRENTLY EXPECTED...THAN CONVECTIVE COVERAGE MAY NEED TO BE INCREASED WITH LATER FORECASTS. EASTERLY FLOW ON SUN WILL ALLOW MARINE INFLUENCES TO PENETRATE WELL INLAND...ACTING TO MODIFY THE MAXIMUM TEMP FORECAST...AND WILL KEEP HIGHS WITHIN A DEG OR TWO OF THE 90 DEG MARK...LOWEST ALONG THE IMMEDIATE COAST. A MORE WESTERLY FLOW ON MON...SHOULD BE ENOUGH TO ADD A COUPLE OF DEG TO THOSE HIGHS. OVERNIGHTS LOWS WILL BE IN THE LOWER TO MID 70S. && .LONG TERM /TUESDAY THROUGH SATURDAY/... AS OF 2 PM SATURDAY...MAIN FOCUS OF THE EXTENDED FORECAST IS ON THE LATTER PERIODS WHEN AN EAST COAST TROUGH DEVELOPS AS RIDGING SHIFTS TO THE WEST. THIS SITUATION LOOKS SOMEWHAT SIMILAR TO THE SYNOPTIC PATTERN ACROSS OUR AREA THE PAST FEW DAYS. EARLY ON...A DIFFUSE MID LEVEL PATTERN WILL PREVAIL WITH A GENERAL WEAKNESS OF HEIGHTS ACROSS THE SOUTHEAST AS WEAK RIDGING PREVAILS ACROSS THE MISSISSIPPI VALLEY. AT THE SURFACE...THE PIEDMONT TROUGH AND SEA BREEZE WILL BE THE FOCUS OF DIURNAL SHOWERS AND THUNDERSTORMS WITH MINIMAL CHANCES BOTH TUESDAY AND WEDNESDAY. MEDIUM RANGE GUIDANCE IS IN GOOD AGREEMENT WITH HEIGHT FALLS FOR THURSDAY THROUGH SATURDAY WITH A SURFACE FRONT MOVING FROM THE MID ATLANTIC TO TAKING RESIDENCE ACROSS CAPE FEAR BY SATURDAY...AGAIN...NOT UNLIKE THE SITUATION WE EXPERIENCED THIS LAST WEEK SO THE PROSPECTS FOR ANOTHER SEVERAL DAYS OF BENEFICIAL RAINS LOOK GOOD AT THIS POINT. INCREASED POPS TO GOOD CHANCE NORTHERN AREAS THURSDAY AND ALL AREAS FRIDAY AND SATURDAY. REGARDING TEMPERATURES...NO REAL SURPRISES FOR THE MIDDLE OF JULY WITH WARM READINGS EARLY ON...PERHAPS A COUPLE OF DEGREES ABOVE CLIMATOLOGY TRENDING SLIGHTLY COOLER LATER IN THE PERIOD COURTESY OF THE BETTER COVERAGE OF SHOWERS AND THUNDERSTORMS. && .AVIATION /00Z SUNDAY THROUGH THURSDAY/... AS OF 00Z...SEA BREEZE CONVECTION HAS ABOUT ENDED FOR THE NIGHT. IT IS NOT IMPOSSIBLE THOUGH THAT COASTAL TERMINALS COULD SEE A PASSING SHOWER AFTER SUNSET AS LAND BREEZE BEGINS TO SET UP AND SE FLOW ENCROACHES UPON IT. CONFIDENCE OF ANY ONE TERMINAL BEING IMPACTED IS LOW. OVERNIGHT...EXPECTATIONS ARE SIMILAR TO LAST NIGHT WITH MVFR FOG POSSIBLE AT ALL TERMINALS FOR BRIEF PERIODS EXCEPT AT LBT WHERE IFR CONDITIONS ARE POSSIBLE. MORE SEA BREEZE CONVECTION IS EXPECTED AFTER ABOUT 17Z SUNDAY BUT COVERAGE SHOULD BE LIMITED AND TSRA WILL NOT BE INCLUDED AT TAFS AT THIS TIME. SE FLOW WILL CONTINUE DURING DAYLIGHT HOURS THROUGH THE PERIOD. EXTENDED OUTLOOK...CHANCE OF AFTERNOON SHOWERS AND MORNING FOG EACH DAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 1030 PM SATURDAY...NO CHANGES ARE NEEDED WITH THIS LATE EVENING NEAR TERM UPDATE. PREVIOUS DISCUSSION FROM 730 PM FOLLOWS... BERMUDA HIGH PRESSURE WELL OFFSHORE EXTENDS A RIDGE AXIS WEST AND TOWARD THE NC COASTLINE. SOUTHEASTERLY FLOW SOUTH OF THE RIDGE WILL CONTINUE THROUGH THE NIGHT AVERAGING 10 KNOTS. CONTAINED WITHIN THIS TROPICAL AIRMASS ARE ISOLATED BRIEF SHOWERS VISIBLE ON SATELLITE AND RADAR DATA ACROSS TENS OF THOUSANDS OF SQUARE MILES OF THE WESTERN ATLANTIC. A FEW OF THESE WILL PROBABLY WORK THEIR WAY INTO THE COASTAL WATERS LATE THIS EVENING AND OVERNIGHT. SEAS AVERAGE 2-3 FT THIS EVENING...HIGHEST NORTH OF CAPE FEAR...WITH DOMINANT PERIODS 5-6 SECONDS (WIND WAVE) AND 8-9 SECONDS (SOUTHEAST SWELL.) SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 2 PM SATURDAY...BERMUDA RIDGE WILL MAINTAIN A SE TO SSE WIND ACROSS THE WATERS SUN. THE SEABREEZE BOUNDARY WILL ENHANCE THE WINDS ACROSS THE NEAR SHORE WATERS SLIGHTLY...BUT STILL SUSTAINED WINDS WILL BE HELD TO AROUND 10 KT. THE WIND DIRECTION WILL VEER TO SW SUN NIGHT AND SPEEDS SHOULD INCREASE SLIGHTLY AS THE PIEDMONT TROUGH DEVELOPS AND STRENGTHENS MON AFTERNOON AND INTO MON NIGHT WITH MODEST NOCTURNAL JETTING NOTED. WILL CAP SUSTAINED SW WINDS AT 15 KT LATER MON AFTERNOON AND NIGHT. SEAS WILL BE IN THE 2 TO 4 FT RANGE THROUGH THE PERIOD. A WEAK 8 TO 9 SECOND EASTERLY SWELL WILL BE PRESENT THROUGH THE PERIOD. LONG TERM /TUESDAY THROUGH THURSDAY/... AS OF 2 PM SATURDAY...SUMMERTIME PATTERN CONTINUES FOR THE MARINE COMMUNITY WITH A SOUTHWESTERLY FLOW OF 10-15 KNOTS THROUGH THE PERIOD. WINDS MAY INCREASE SLIGHTLY LATE IN THE PERIOD AS A FRONT MOVING IN FROM THE MID ATLANTIC ENHANCES THE PIEDMONT TROUGH. WINDS AT THAT POINT COULD INCREASE TO A RANGE OF 15-20 KNOTS. SEAS ARE 2-4 FEET THROUGHOUT BUT COULD INCREASE LATE WEDNESDAY INTO THURSDAY VIA THE ENHANCEMENT OF THE PIEDMONT TROUGH WITH THE POSSIBILITY OF SOME FIVE FOOTERS. && .EQUIPMENT... AS OF 1030 PM SATURDAY...PLEASE BE CAREFUL USING PRECIPITATION DATA FROM THE FLORENCE SC ASOS (KFLO) UNTIL TECHNICIANS ARE ABLE TO ACCESS WHAT IS WRONG WITH THE RAIN GAUGE. SEVERAL TIMES EARLIER THIS YEAR THE GAUGE BECAME CLOGGED WITH BIRD DROPPINGS...AND THIS MAY HAVE HAPPENED AGAIN TODAY WHERE VERY LARGE DIFFERENCES BETWEEN RADAR-ESTIMATED RAINFALL AND ASOS-REPORTED RAINFALL EXIST. ALSO...OBSERVATIONS FROM THE SOUTHPORT NC (KSUT) AWOS OF REDUCED VISIBILITY AND A LOW CLOUD CEILING THIS EVENING ARE PROBABLY FALSE. SIMILAR DUBIOUS OBSERVATIONS OCCURRED AT THIS STATION LAST NIGHT. THIS AWOS IS MAINTAINED BY THE NC DEPARTMENT OF TRANSPORTATION AND NOT THE NWS. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...TRA SHORT TERM...RJD LONG TERM...SHK AVIATION...RAN EQUIPMENT...TRA
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
630 AM EDT FRI JUL 13 2012 .SYNOPSIS... A WEAK FRONT STALLED OVER THE CAROLINAS PLUS A HUMID TROPICAL AIRMASS WILL BRING A CONTINUING RISK OF SHOWERS AND THUNDERSTORMS THROUGH SATURDAY. A GRADUAL DRYING TREND WILL BEGIN SATURDAY AS BERMUDA HIGH PRESSURE STRENGTHENS OVER THE AREA. && .NEAR TERM /THROUGH TONIGHT/... AS OF 333 AM FRIDAY...MODELS INDICATE DEEPER ONSHORE TROPICAL FLOW...E TO SE WINDS...WILL BECOME MORE DOMINATE THRU THE ATM COLUMN DURING THIS NEAR TERM PERIOD. NAMBUFR HOURLY SOUNDINGS THRU SATURDAY MORNING HIGHLIGHT THIS NICELY. VIA LATEST KLTX 88D...ALONG WITH THE LATEST HRRR MODEL RUNS...THE ADJACENT ATLANTIC NOCTURNAL SHRA ENGINE HAS RAMPED UP EARLY THIS MORNING. TRAJECTORIES MOVE THIS ISOLATED/SCATTERED PCPN OCCASIONALLY ONSHORE THROUGH SUNRISE...WITH MUCH OF IT DISSIPATING AS IT MOVES FURTHER INLAND. THIS ENGINE WILL SLOWLY DWINDLE DOWN AFTER SUNRISE. PWS TO REMAIN IN THAT 2 INCH REALM THRUOUT THE NEAR TERM AND WILL NOT TAKE TOO MUCH FORCING TO IGNITE CONVECTION DURING THE DAY. DRIER AIR TO EVENTUALLY START FILTERING INTO THE FA BY SATURDAY. NEVERTHELESS...THE DAYS INSOLATION TO PROVIDE SOME DESTABILIZATION SEVERAL HRS AFTER SUNRISE ALLOWING FOR CONVECTION TO DEVELOP MAINLY ALONG THE IMMEDIATE COAST. THE ACTIVITY WILL EXPAND INLAND THRUOUT THE DAY. MODEL SOUNDINGS INDICATE CONTINUED SLOW STORM MOTIONS IE. NW AT 5 MPH...AND WITH PCPN MORE TROPICAL IN NATURE...EXPECT POSSIBLE HEAVY DOWNPOURS FROM ANY CONVECTIVE ACTIVITY...EVEN WITHOUT THE PRESENCE OF THUNDER. ONCE THE DAYS INSOLATION ENDS...OR THE AVAILABLE CAPE IS USED UP...CONVECTION WILL QUICKLY DISSIPATE THIS EVENING...LEAVING CONVECTIVE DEBRIS CLOUDS FOR THE REMAINDER OF TONIGHT. MODELS AGAIN RAMP UP THE NOCTURNAL ATLANTIC SHRA ENGINE AFTER MIDNIGHT TONIGHT...WITH SPORADIC ONSHORE MOVEMENT OF THE PCPN. AS FOR MAX/MIN TEMPS...MAINLY COMPROMISED BETWEEN THE NAM AND GFS MOS GUIDANCE. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... AS OF 3 AM FRIDAY..UPPER RIDGE BUILDS INTO THE REGION FROM POINTS EAST ON SATURDAY. MEANWHILE SURFACE HIGH ACROSS THE WEST ATLANTIC REMAINS QUITE WEAK. A VERY DEEP BUT WEAK EAST TO SOUTHEASTERLY FLOW WILL SET UP AND THE MID LEVELS WILL DRY SLIGHTLY BUT NOT SO MUCH HAD THE HEIGHT RISES BUILT IN FROM THE WEST. SOME VERY BRIEF MORNING TROPICAL SHOWERS APPEAR POSSIBLE ALONG THE COAST MAINLY IN THE MORNING. AFTERNOON CONVECTION SHOULD BE ISOLATED AT BEST DUE TO THE MID LEVEL DRYING...AND MAY STAY WEST OF THE FORECAST AREA ALTOGETHER. AN UPPER LOW WILL BE APPROACHING IN THE EASTERLY FLOW AND MODEL SPREAD IS CONSIDERABLE WITH NOT ONLY THE TRACK OF THIS SYSTEM BUT ALSO WHETHER OR NOT IT HAS ANY SURFACE REFLECTION. MODELS HAVE SLOWED WITH ITS PROGRESSION AND IT NOW LOOKS LIKE IT WILL STAY EAST OF THE REGION DURING THE SHORT TERM...IF IT AFFECTS US AT ALL. SUNDAY WILL THUS END UP VERY SIMILAR TO SATURDAY AS FAR AS RAIN DISTRIBUTION AND CHANCES. GUIDANCE SHOWING SUNDAY AFTERNOON TURNING OUT A LITTLE WARMER THAN SAT BUT NOT SO MUCH AS PREV FCST SO A SMALL TWEAK WAS MADE THERE. && .LONG TERM /MONDAY THROUGH THURSDAY/... AS OF 3 AM FRIDAY...BARRING ANY SIGNIFICANT WEATHER RESULTING FROM THE UPPER LOW COMING FROM THE EAST THE LONG TERM LOOKS VERY QUIET. AFOREMENTIONED LOW MAY RECURVE FROM THE COAST OR CONTINUE WESTWARD OVER LAND...MODELS AREN`T TOO SURE. OTHERWISE MID LEVEL FLOW WILL BE LIGHT AND VARIABLE AND THE WEST ATLANTIC HIGH WILL SHOW LITTLE MOVEMENT. MOISTURE RETURN LOOKS WEAK BUT SOME ISOLATED DIURNAL CONVECTION STILL SEEMS LIKELY EACH DAY. TEMPERATURES WILL BE RIGHT WHERE THEY SHOULD BE FOR THE TIME OF YEAR. && .AVIATION /12Z FRIDAY THROUGH TUESDAY/... AS OF 12Z...LIFR CONDITIONS INLAND SHOULD MIX OUT FAIRLY QUICKLY WITH THE JULY SUN...13-14Z. A MVFR CUMULUS CEILING MAY FORM AROUND 14Z...WITH HIGH PWATS AND LOW LFC. ONSHORE FLOW WILL CREATE SHOWERS A BIT EARLIER THAN USUAL ALONG THE SEA BREEZE BOUNDARY...MOVING WEST OF THE COASTAL TERMINALS BY 18-19Z. A RUMBLE OF THUNDER IS POSSIBLE...BUT MOST OF THE ACTIVITY WILL BE LOW TOPPED...TROPICAL IN NATURE. TONIGHT...SOUTHEAST FLOW WILL PREVAIL THROUGH MOST OF THE TROPOSPHERE WITH EXCELLENT VISIBILITIES EARLY. POSSIBLE MVFR FOG TOWARD MORNING...DEPENDING ON CLOUD COVER AND RADIATIONAL COOLING CONDITIONS. EXTENDED OUTLOOK...A CHANCE OF THUNDERSTORMS EACH DAY...MAINLY IN THE AFTERNOON AND EVENING. OTHERWISE EXPECT VFR. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 345 AM FRIDAY...THE SFC RIDGE AXIS EXTENDING WEST AND INLAND FROM THE WESTERN ATLANTIC HIGH AKA BERMUDA HIGH...WILL REMAIN JUST NORTH OF THE COASTAL WATERS. THIS SFC PRESSURE PATTERN WILL YIELD A E-SE WIND FLOW AROUND 10 KT. IN FACT BY SATURDAY MORNING...MODEL SOUNDINGS OVER THE WATERS INDICATE A DEEP TROPICAL SE FLOW TO HAVE EVOLVED...IE. SFC THRU 50K FT. THE SFC PG WILL REMAIN RATHER RELAXED THRU THE PERIOD...RESULTING WITH CONTINUED 10 KT WIND SPEEDS. SCATTERED ATLANTIC SHRA ACTIVITY WILL BE HIGHER DURING THE NOCTURNAL PORTIONS OF THE 24 HR DAY...WANING TO JUST ISOLATED DURING THE DAY. SIG SEAS WILL BECOME DOMINATED BY THE ESE GROUND SWELL AT 1 TO 2 FT...BUILDING TO 2 TO 3 FT...AND LIKELY HIGHER BEYOND THE NEAR TERM PERIOD. WAVEWATCH3 ILLUSTRATES THE INITIAL SWELL INCREASE TODAY...AND THEN FURTHER BUILDING IT TO POSSIBLY UP TO 4 FT SATURDAY. RIP CURRENT RISK WILL BE ON THE INCREASE THIS WEEKEND. THE IN-HOUSE WATERSPOUT RISK ASSESSMENT PLACES A MODERATE CHANCE ACROSS THE LOCAL WATERS TODAY. WILL HIGHLIGHT ITS POSSIBILITY IN THE COASTAL SECTION OF THE HAZARDOUS WEATHER OUTLOOK. SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... AS OF 3 AM FRIDAY..WEAK HIGH PRESSURE ACROSS THE WESTERN ATLANTIC ON SATURDAY WITH A SIMILARLY SUBTLE TROUGH WELL OFF THE COAST BY SUNDAY. THE LATTER WILL TILT FLOW FROM THE SOUTHEAST TO EAST OR EVEN NORTHEASTER WHILE SPEEDS REMAIN CAPPED AT JUST 10 KT. THE UPPER FEATURE DEVELOPING THIS TROUGH IS RATHER STRONG BY JULY STANDARDS AND COULD LEAD TO A SURFACE FEATURE STRONGER THAN CURRENTLY DEPICTED IN GUIDANCE. IF THIS TURNS OUT TO BE THE CASE THEN WINDS WILL BE A BIT HIGHER THAN FORECAST WITH A SIMILAR ADJUSTMENT MAYBE NEEDED FOR SEAS. OTHERWISE WAVES WILL STAY AT OR BELOW 3 FT. LONG TERM /MONDAY THROUGH TUESDAY/... AS OF 3 AM FRIDAY...SOUTHWEST WINDS GENERALLY IN THE 10 TO 15 KT RANGE AND SEAS AVERAGING 2 TO 4 FT THROUGH THE PERIOD...THE MOST COMMON SET OF CONDITIONS LOCALLY FOR THE SUMMER. HIGH PRESSURE ACROSS THE WEST ATLANTIC WILL BE FAIRLY WEAK. SWELL ENERGY PROGGED TO BE AROUND 10 SEC AND THE WIND CHOP 4-5 SECONDS. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ SYNOPSIS...MBB NEAR TERM...DCH SHORT TERM...MBB LONG TERM...MBB AVIATION...43
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
405 AM EDT FRI JUL 13 2012 .SYNOPSIS... A WEAK FRONT STALLED OVER THE CAROLINAS PLUS A HUMID TROPICAL AIRMASS WILL BRING A CONTINUING RISK OF SHOWERS AND THUNDERSTORMS THROUGH SATURDAY. A GRADUAL DRYING TREND WILL BEGIN SATURDAY AS BERMUDA HIGH PRESSURE STRENGTHENS OVER THE AREA. && .NEAR TERM /THROUGH TONIGHT/... AS OF 333 AM FRIDAY...MODELS INDICATE DEEPER ONSHORE TROPICAL FLOW...E TO SE WINDS...WILL BECOME MORE DOMINATE THRU THE ATM COLUMN DURING THIS NEAR TERM PERIOD. NAMBUFR HOURLY SOUNDINGS THRU SATURDAY MORNING HIGHLIGHT THIS NICELY. VIA LATEST KLTX 88D...ALONG WITH THE LATEST HRRR MODEL RUNS...THE ADJACENT ATLANTIC NOCTURNAL SHRA ENGINE HAS RAMPED UP EARLY THIS MORNING. TRAJECTORIES MOVE THIS ISOLATED/SCATTERED PCPN OCCASIONALLY ONSHORE THROUGH SUNRISE...WITH MUCH OF IT DISSIPATING AS IT MOVES FURTHER INLAND. THIS ENGINE WILL SLOWLY DWINDLE DOWN AFTER SUNRISE. PWS TO REMAIN IN THAT 2 INCH REALM THRUOUT THE NEAR TERM AND WILL NOT TAKE TOO MUCH FORCING TO IGNITE CONVECTION DURING THE DAY. DRIER AIR TO EVENTUALLY START FILTERING INTO THE FA BY SATURDAY. NEVERTHELESS...THE DAYS INSOLATION TO PROVIDE SOME DESTABILIZATION SEVERAL HRS AFTER SUNRISE ALLOWING FOR CONVECTION TO DEVELOP MAINLY ALONG THE IMMEDIATE COAST. THE ACTIVITY WILL EXPAND INLAND THRUOUT THE DAY. MODEL SOUNDINGS INDICATE CONTINUED SLOW STORM MOTIONS IE. NW AT 5 MPH...AND WITH PCPN MORE TROPICAL IN NATURE...EXPECT POSSIBLE HEAVY DOWNPOURS FROM ANY CONVECTIVE ACTIVITY...EVEN WITHOUT THE PRESENCE OF THUNDER. ONCE THE DAYS INSOLATION ENDS...OR THE AVAILABLE CAPE IS USED UP...CONVECTION WILL QUICKLY DISSIPATE THIS EVENING...LEAVING CONVECTIVE DEBRIS CLOUDS FOR THE REMAINDER OF TONIGHT. MODELS AGAIN RAMP UP THE NOCTURNAL ATLANTIC SHRA ENGINE AFTER MIDNIGHT TONIGHT...WITH SPORADIC ONSHORE MOVEMENT OF THE PCPN. AS FOR MAX/MIN TEMPS...MAINLY COMPROMISED BETWEEN THE NAM AND GFS MOS GUIDANCE. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... AS OF 3 AM FRIDAY..UPPER RIDGE BUILDS INTO THE REGION FROM POINTS EAST ON SATURDAY. MEANWHILE SURFACE HIGH ACROSS THE WEST ATLANTIC REMAINS QUITE WEAK. A VERY DEEP BUT WEAK EAST TO SOUTHEASTERLY FLOW WILL SET UP AND THE MID LEVELS WILL DRY SLIGHTLY BUT NOT SO MUCH HAD THE HEIGHT RISES BUILT IN FROM THE WEST. SOME VERY BRIEF MORNING TROPICAL SHOWERS APPEAR POSSIBLE ALONG THE COAST MAINLY IN THE MORNING. AFTERNOON CONVECTION SHOULD BE ISOLATED AT BEST DUE TO THE MID LEVEL DRYING...AND MAY STAY WEST OF THE FORECAST AREA ALTOGETHER. AN UPPER LOW WILL BE APPROACHING IN THE EASTERLY FLOW AND MODEL SPREAD IS CONSIDERABLE WITH NOT ONLY THE TRACK OF THIS SYSTEM BUT ALSO WHETHER OR NOT IT HAS ANY SURFACE REFLECTION. MODELS HAVE SLOWED WITH ITS PROGRESSION AND IT NOW LOOKS LIKE IT WILL STAY EAST OF THE REGION DURING THE SHORT TERM...IF IT AFFECTS US AT ALL. SUNDAY WILL THUS END UP VERY SIMILAR TO SATURDAY AS FAR AS RAIN DISTRIBUTION AND CHANCES. GUIDANCE SHOWING SUNDAY AFTERNOON TURNING OUT A LITTLE WARMER THAN SAT BUT NOT SO MUCH AS PREV FCST SO A SMALL TWEAK WAS MADE THERE. && .LONG TERM /MONDAY THROUGH THURSDAY/... AS OF 3 AM FRIDAY...BARRING ANY SIGNIFICANT WEATHER RESULTING FROM THE UPPER LOW COMING FROM THE EAST THE LONG TERM LOOKS VERY QUIET. AFOREMENTIONED LOW MAY RECURVE FROM THE COAST OR CONTINUE WESTWARD OVER LAND...MODELS AREN`T TOO SURE. OTHERWISE MID LEVEL FLOW WILL BE LIGHT AND VARIABLE AND THE WEST ATLANTIC HIGH WILL SHOW LITTLE MOVEMENT. MOISTURE RETURN LOOKS WEAK BUT SOME ISOLATED DIURNAL CONVECTION STILL SEEMS LIKELY EACH DAY. TEMPERATURES WILL BE RIGHT WHERE THEY SHOULD BE FOR THE TIME OF YEAR. && .AVIATION /06Z FRIDAY THROUGH TUESDAY/... AS OF 06Z...PERIODS OF MVFR/IFR OVERNIGHT DUE FOG/STRATUS THROUGH THE EARLY FRIDAY MORNING HRS. MORNING MVFR CONVECTION AT THE COASTAL TERMS...WILL EXPAND TO THE INLAND TERMS THIS AFTERNOON. FCST GUIDANCE/LATEST KLTX88D SUGGEST ADDITIONAL SHRA/TSRA TO DEVELOP OVER THE ADJACENT ATLANTIC WATERS EARLY THIS MORNING ...SPORADICALLY MOVING ONSHORE PRIOR TO SUNRISE. FOR NOW HAVE INTRODUCED VCSH. GIVEN ABUNDANT RAINFALL IN SOME LOCATIONS AND LIGHT AND VARIABLE WINDS...ANTICIPATE MVFR FOG...WITH MVFR/IFR LOW CIGS DUE TO STRATUS EARLY THIS MORNING. EXPECT ANY LINGERING FOG TO CLEAR OUT BY SEVERAL HRS AFTER SUNRISE. GUIDANCE DEPICTS CIGS BETWEEN 2000-3000FT AND ISOLATED/SCATTERED TSRA AT THE COAST AFTER SUNRISE...EXPANDING INLAND BY THE EARLY AFTERNOON. SYNOPTIC NE-E WINDS 5 KT OR LESS THIS MORNING WILL VEER TO THE SE 5 TO 10 KT... WITH GUSTS UP TO 15 KT AT THE COASTAL TERMS...BY MIDDAY. ANTICIPATE STORMS TO GRADUALLY TAPER OFF INTO THE LATE EVENING HOURS. EXTENDED OUTLOOK...A CHANCE OF THUNDERSTORMS EACH DAY...MAINLY IN THE AFTERNOON AND EVENING. OTHERWISE EXPECT VFR. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 345 AM FRIDAY...THE SFC RIDGE AXIS EXTENDING WEST AND INLAND FROM THE WESTERN ATLANTIC HIGH AKA BERMUDA HIGH...WILL REMAIN JUST NORTH OF THE COASTAL WATERS. THIS SFC PRESSURE PATTERN WILL YIELD A E-SE WIND FLOW AROUND 10 KT. IN FACT BY SATURDAY MORNING...MODEL SOUNDINGS OVER THE WATERS INDICATE A DEEP TROPICAL SE FLOW TO HAVE EVOLVED...IE. SFC THRU 50K FT. THE SFC PG WILL REMAIN RATHER RELAXED THRU THE PERIOD...RESULTING WITH CONTINUED 10 KT WIND SPEEDS. SCATTERED ATLANTIC SHRA ACTIVITY WILL BE HIGHER DURING THE NOCTURNAL PORTIONS OF THE 24 HR DAY...WANING TO JUST ISOLATED DURING THE DAY. SIG SEAS WILL BECOME DOMINATED BY THE ESE GROUND SWELL AT 1 TO 2 FT...BUILDING TO 2 TO 3 FT...AND LIKELY HIGHER BEYOND THE NEAR TERM PERIOD. WAVEWATCH3 ILLUSTRATES THE INITIAL SWELL INCREASE TODAY...AND THEN FURTHER BUILDING IT TO POSSIBLY UP TO 4 FT SATURDAY. RIP CURRENT RISK WILL BE ON THE INCREASE THIS WEEKEND. THE IN-HOUSE WATERSPOUT RISK ASSESSMENT PLACES A MODERATE CHANCE ACROSS THE LOCAL WATERS TODAY. WILL HIGHLIGHT ITS POSSIBILITY IN THE COASTAL SECTION OF THE HAZARDOUS WEATHER OUTLOOK. SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... AS OF 3 AM FRIDAY..WEAK HIGH PRESSURE ACROSS THE WESTERN ATLANTIC ON SATURDAY WITH A SIMILARLY SUBTLE TROUGH WELL OFF THE COAST BY SUNDAY. THE LATTER WILL TILT FLOW FROM THE SOUTHEAST TO EAST OR EVEN NORTHEASTER WHILE SPEEDS REMAIN CAPPED AT JUST 10 KT. THE UPPER FEATURE DEVELOPING THIS TROUGH IS RATHER STRONG BY JULY STANDARDS AND COULD LEAD TO A SURFACE FEATURE STRONGER THAN CURRENTLY DEPICTED IN GUIDANCE. IF THIS TURNS OUT TO BE THE CASE THEN WINDS WILL BE A BIT HIGHER THAN FORECAST WITH A SIMILAR ADJUSTMENT MAYBE NEEDED FOR SEAS. OTHERWISE WAVES WILL STAY AT OR BELOW 3 FT. LONG TERM /MONDAY THROUGH TUESDAY/... AS OF 3 AM FRIDAY...SOUTHWEST WINDS GENERALLY IN THE 10 TO 15 KT RANGE AND SEAS AVERAGING 2 TO 4 FT THROUGH THE PERIOD...THE MOST COMMON SET OF CONDITIONS LOCALLY FOR THE SUMMER. HIGH PRESSURE ACROSS THE WEST ATLANTIC WILL BE FAIRLY WEAK. SWELL ENERGY PROGGED TO BE AROUND 10 SEC AND THE WIND CHOP 4-5 SECONDS. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ SYNOPSIS...MBB NEAR TERM...DCH SHORT TERM...MBB LONG TERM...MBB AVIATION...DCH/SGL
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
355 AM EDT FRI JUL 13 2012 .SYNOPSIS... A WEAK FRONT STALLED OVER THE CAROLINAS PLUS A HUMID TROPICAL AIRMASS WILL BRING A CONTINUING RISK OF SHOWERS AND THUNDERSTORMS THROUGH SATURDAY. A GRADUAL DRYING TREND WILL BEGIN SATURDAY AS BERMUDA HIGH PRESSURE STRENGTHENS OVER THE AREA. && .NEAR TERM /THROUGH TONIGHT/... AS OF 333 AM FRIDAY...MODELS INDICATE DEEPER ONSHORE TROPICAL FLOW...E TO SE WINDS...WILL BECOME MORE DOMINATE THRU THE ATM COLUMN DURING THIS NEAR TERM PERIOD. NAMBUFR HOURLY SOUNDINGS THRU SATURDAY MORNING HIGHLIGHT THIS NICELY. VIA LATEST KLTX 88D...ALONG WITH THE LATEST HRRR MODEL RUNS...THE ADJACENT ATLANTIC NOCTURNAL SHRA ENGINE HAS RAMPED UP EARLY THIS MORNING. TRAJECTORIES MOVE THIS ISOLATED/SCATTERED PCPN OCCASIONALLY ONSHORE THROUGH SUNRISE...WITH MUCH OF IT DISSIPATING AS IT MOVES FURTHER INLAND. THIS ENGINE WILL SLOWLY DWINDLE DOWN AFTER SUNRISE. PWS TO REMAIN IN THAT 2 INCH REALM THRUOUT THE NEAR TERM AND WILL NOT TAKE TOO MUCH FORCING TO IGNITE CONVECTION DURING THE DAY. DRIER AIR TO EVENTUALLY START FILTERING INTO THE FA BY SATURDAY. NEVERTHELESS...THE DAYS INSOLATION TO PROVIDE SOME DESTABILIZATION SEVERAL HRS AFTER SUNRISE ALLOWING FOR CONVECTION TO DEVELOP MAINLY ALONG THE IMMEDIATE COAST. THE ACTIVITY WILL EXPAND INLAND THRUOUT THE DAY. MODEL SOUNDINGS INDICATE CONTINUED SLOW STORM MOTIONS IE. NW AT 5 MPH...AND WITH PCPN MORE TROPICAL IN NATURE...EXPECT POSSIBLE HEAVY DOWNPOURS FROM ANY CONVECTIVE ACTIVITY...EVEN WITHOUT THE PRESENCE OF THUNDER. ONCE THE DAYS INSOLATION ENDS...OR THE AVAILABLE CAPE IS USED UP...CONVECTION WILL QUICKLY DISSIPATE THIS EVENING...LEAVING CONVECTIVE DEBRIS CLOUDS FOR THE REMAINDER OF TONIGHT. MODELS AGAIN RAMP UP THE NOCTURNAL ATLANTIC SHRA ENGINE AFTER MIDNIGHT TONIGHT...WITH SPORADIC ONSHORE MOVEMENT OF THE PCPN. AS FOR MAX/MIN TEMPS...MAINLY COMPROMISED BETWEEN THE NAM AND GFS MOS GUIDANCE. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... AS OF 3 AM FRIDAY..UPPER RIDGE BUILDS INTO THE REGION FROM POINTS EAST ON SATURDAY. MEANWHILE SURFACE HIGH ACROSS THE WEST ATLANTIC REMAINS QUITE WEAK. A VERY DEEP BUT WEAK EAST TO SOUTHEASTERLY FLOW WILL SET UP AND THE MID LEVELS WILL DRY SLIGHTLY BUT NOT SO MUCH HAD THE HEIGHT RISES BUILT IN FROM THE WEST. SOME VERY BRIEF MORNING TROPICAL SHOWERS APPEAR POSSIBLE ALONG THE COAST MAINLY IN THE MORNING. AFTERNOON CONVECTION SHOULD BE ISOLATED AT BEST DUE TO THE MID LEVEL DRYING...AND MAY STAY WEST OF THE FORECAST AREA ALTOGETHER. AN UPPER LOW WILL BE APPROACHING IN THE EASTERLY FLOW AND MODEL SPREAD IS CONSIDERABLE WITH NOT ONLY THE TRACK OF THIS SYSTEM BUT ALSO WHETHER OR NOT IT HAS ANY SURFACE REFLECTION. MODELS HAVE SLOWED WITH ITS PROGRESSION AND IT NOW LOOKS LIKE IT WILL STAY EAST OF THE REGION DURING THE SHORT TERM...IF IT AFFECTS US AT ALL. SUNDAY WILL THUS END UP VERY SIMILAR TO SATURDAY AS FAR AS RAIN DISTRIBUTION AND CHANCES. GUIDANCE SHOWING SUNDAY AFTERNOON TURNING OUT A LITTLE WARMER THAN SAT BUT NOT SO MUCH AS PREV FCST SO A SMALL TWEAK WAS MADE THERE. && .LONG TERM /MONDAY THROUGH THURSDAY/... AS OF 3 AM FRIDAY...BARRING ANY SIGNIFICANT WEATHER RESULTING FROM THE UPPER LOW COMING FROM THE EAST THE LONG TERM LOOKS VERY QUIET. AFOREMENTIONED LOW MAY RECURVE FROM THE COAST OR CONTINUE WESTWARD OVER LAND...MODELS AREN`T TOO SURE. OTHERWISE MID LEVEL FLOW WILL BE LIGHT AND VARIABLE AND THE WEST ATLANTIC HIGH WILL SHOW LITTLE MOVEMENT. MOISTURE RETURN LOOKS WEAK BUT SOME ISOLATED DIURNAL CONVECTION STILL SEEMS LIKELY EACH DAY. TEMPERATURES WILL BE RIGHT WHERE THEY SHOULD BE FOR THE TIME OF YEAR. && .AVIATION /06Z FRIDAY THROUGH TUESDAY/... AS OF 06Z...PERIODS OF MVFR/IFR OVERNIGHT DUE FOG/STRATUS THROUGH THE EARLY FRIDAY MORNING HRS. MORNING MVFR CONVECTION AT THE COASTAL TERMS...WILL EXPAND TO THE INLAND TERMS THIS AFTERNOON. FCST GUIDANCE/LATEST KLTX88D SUGGEST ADDITIONAL SHRA/TSRA TO DEVELOP OVER THE ADJACENT ATLANTIC WATERS EARLY THIS MORNING ...SPORADICALLY MOVING ONSHORE PRIOR TO SUNRISE. FOR NOW HAVE INTRODUCED VCSH. GIVEN ABUNDANT RAINFALL IN SOME LOCATIONS AND LIGHT AND VARIABLE WINDS...ANTICIPATE MVFR FOG...WITH MVFR/IFR LOW CIGS DUE TO STRATUS EARLY THIS MORNING. EXPECT ANY LINGERING FOG TO CLEAR OUT BY SEVERAL HRS AFTER SUNRISE. GUIDANCE DEPICTS CIGS BETWEEN 2000-3000FT AND ISOLATED/SCATTERED TSRA AT THE COAST AFTER SUNRISE...EXPANDING INLAND BY THE EARLY AFTERNOON. SYNOPTIC NE-E WINDS 5 KT OR LESS THIS MORNING WILL VEER TO THE SE 5 TO 10 KT... WITH GUSTS UP TO 15 KT AT THE COASTAL TERMS...BY MIDDAY. ANTICIPATE STORMS TO GRADUALLY TAPER OFF INTO THE LATE EVENING HOURS. EXTENDED OUTLOOK...A CHANCE OF THUNDERSTORMS EACH DAY...MAINLY IN THE AFTERNOON AND EVENING. OTHERWISE EXPECT VFR. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 1030 PM THURSDAY...THE FRONT INLAND HAS ACTUALLY SLID SOUTH AS A COLD FRONT TO NEAR CAPE FEAR LATE THIS EVENING. NORTHEAST WINDS ARE NOW BEING OBSERVED AT WRIGHTSVILLE BEACH AND AT THE WILMINGTON AIRPORT. WITH NO INCREASE IN SOUTHEASTERLY WINDS OFFSHORE EXPECTED THERE IS LITTLE REASON TO BELIEVE THE BOUNDARY WILL SUDDENLY SHIFT BACK TO THE NORTH OVERNIGHT...SO WE`VE ADJUSTED OUR WIND FORECAST TO SHOW EAST TO NORTHEAST FLOW NEAR AND NORTH OF CAPE FEAR OVERNIGHT. FORTUNATELY NO INCREASE IN WIND SPEEDS ARE EXPECTED. ANY OTHER CHANGES TO THE FORECAST ARE MINOR THIS EVENING. PREVIOUS DISCUSSION FROM 730 PM FOLLOWS... A WEAK FRONT STALLED ACROSS THE INLAND CAROLINAS HELPED FOCUS SHOWER AND THUNDERSTORM ACTIVITY THERE THIS AFTERNOON. ACROSS THE COASTAL WATERS A SOUTHEAST WIND AROUND 10 KT WILL CONTINUE THROUGH THE NIGHT. AS IS TYPICAL IN THESE TROPICAL AIRMASSES SCATTERED SHOWERS AND EVEN A FEW THUNDERSTORMS MAY DEVELOP ACROSS THE COASTAL WATERS OVERNIGHT IN THIS WARM AND HUMID REGIME. ACTIVITY SHOULD GENERALLY DRIFT TOWARD THE NORTH-NORTHWEST AND MAY BEGIN TO REACH THE BEACHES AFTER 3 AM ACCORDING TO THE LATEST RAPID-UPDATE HRRR COMPUTER MODEL. ALTHOUGH SEVERE WEATHER IS NOT EXPECTED BRIEFLY HEAVY RAINFALL AND THE POTENTIAL OF WATERSPOUTS WILL EXIST. AREA BUOYS SHOW 2-FOOT SEAS THIS EVENING WITH ALMOST ALL OF THE WAVE ENERGY EMBODIED IN A 9-SECOND SOUTHEAST SWELL. NO SIGNIFICANT CHANGE IS EXPECTED OVERNIGHT. SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... AS OF 3 AM FRIDAY..WEAK HIGH PRESSURE ACROSS THE WESTERN ATLANTIC ON SATURDAY WITH A SIMILARLY SUBTLE TROUGH WELL OFF THE COAST BY SUNDAY. THE LATTER WILL TILT FLOW FROM THE SOUTHEAST TO EAST OR EVEN NORTHEASTER WHILE SPEEDS REMAIN CAPPED AT JUST 10 KT. THE UPPER FEATURE DEVELOPING THIS TROUGH IS RATHER STRONG BY JULY STANDARDS AND COULD LEAD TO A SURFACE FEATURE STRONGER THAN CURRENTLY DEPICTED IN GUIDANCE. IF THIS TURNS OUT TO BE THE CASE THEN WINDS WILL BE A BIT HIGHER THAN FORECAST WITH A SIMILAR ADJUSTMENT MAYBE NEEDED FOR SEAS. OTHERWISE WAVES WILL STAY AT OR BELOW 3 FT. LONG TERM /MONDAY THROUGH TUESDAY/... AS OF 3 AM FRIDAY...SOUTHWEST WINDS GENERALLY IN THE 10 TO 15 KT RANGE AND SEAS AVERAGING 2 TO 4 FT THROUGH THE PERIOD...THE MOST COMMON SET OF CONDITIONS LOCALLY FOR THE SUMMER. HIGH PRESSURE ACROSS THE WEST ATLANTIC WILL BE FAIRLY WEAK. SWELL ENERGY PROGGED TO BE AROUND 10 SEC AND THE WIND CHOP 4-5 SECONDS. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...TRA SHORT TERM...MBB LONG TERM...MBB AVIATION...DCH/SGL
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
309 AM EDT FRI JUL 13 2012 .SYNOPSIS... A WEAK FRONT STALLED OVER THE CAROLINAS PLUS A HUMID TROPICAL AIRMASS WILL BRING A CONTINUING RISK OF SHOWERS AND THUNDERSTORMS THROUGH SATURDAY. A GRADUAL DRYING TREND WILL BEGIN SATURDAY AS BERMUDA HIGH PRESSURE STRENGTHENS OVER THE AREA. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1030 PM THURSDAY...THE FRONT HAS ACTUALLY PUSHED SOUTH THROUGH WILMINGTON...WHITEVILLE...CONWAY...MARION AND FLORENCE THIS EVENING WHERE WEAK NORTHEAST WINDS ARE NOW BEING OBSERVED. ABOVE AND AHEAD OF THE BOUNDARY NO INCREASE IN SOUTHEAST WINDS ARE EXPECTED SO THERE IS LITTLE REASON TO BELIEVE THE BOUNDARY WILL SUDDENLY SHIFT BACK TO THE THE NORTH. THERE IS LITTLE REAL AIRMASS DIFFERENCE ON EITHER SIDE OF THE FRONT SO IMPACTS ON SENSIBLE WEATHER (OTHER THAN WIND DIRECTION) ARE LIKELY TO BE MINOR. PREVIOUS DISCUSSION FROM 730 PM FOLLOWS... A STATIONARY FRONT ACROSS THE CAROLINAS IS OUTLINED ALONG A WEAK PRESSURE TROUGH AND BY A SHIFT FROM SOUTHEAST TO NORTHEAST WINDS. THE FRONT RUNS APPROXIMATELY FROM JACKSONVILLE NC ACROSS SOUTHERN DUPLIN AND SAMPSON COUNTIES TO NEAR FAYETTEVILLE...THEN SOUTHWESTWARD THROUGH BENNETTSVILLE AND DARLINGTON TO JUST NORTH OF COLUMBIA. THUNDERSTORMS IGNITED TODAY ALONG THIS FRONT AND ALSO ALONG THE SEABREEZE BOUNDARY...PUSHED SLOWLY NORTHWESTWARD BY THE 0-6 KM MEAN WIND. SURFACE-BASED INSTABILITY HAS BEEN NEARLY EXHAUSTED NOW WITH RADAR PRECIPITATION ESTIMATES SHOWING AT LEAST 80 PERCENT OF OUR FORECAST AREA RECEIVED SOME RAINFALL TODAY. INLAND CONVECTION SHOULD COMPLETELY DISSIPATE OVER THE NEXT 2 HOURS BUT PLENTY OF CONVECTIVE DEBRIS CLOUDINESS WILL REMAIN THROUGH THE NIGHT. ATTENTION THEN WILL SHIFT BACK TO THE COASTAL WATERS WHERE THE HRRR AND EVEN THE SYNOPTIC MODELS (GFS AND NAM) SHOW A RENEWED FOCUS FOR CONVECTION AFTER MIDNIGHT. THE STEERING FLOW WILL REMAIN ORIENTED ONSHORE MEANING WE WILL CONTINUE TO SHOW INCREASING PROBABILITIES FOR SHOWERS AND THUNDERSTORMS FOR THE COASTAL COUNTIES LATE TONIGHT. LOWS TONIGHT SHOULD REACH 70-75...WARMEST AT THE BEACHES. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... AS OF 3 AM FRIDAY..UPPER RIDGE BUILDS INTO THE REGION FROM POINTS EAST ON SATURDAY. MEANWHILE SURFACE HIGH ACROSS THE WEST ATLANTIC REMAINS QUITE WEAK. A VERY DEEP BUT WEAK EAST TO SOUTHEASTERLY FLOW WILL SET UP AND THE MID LEVELS WILL DRY SLIGHTLY BUT NOT SO MUCH HAD THE HEIGHT RISES BUILT IN FROM THE WEST. SOME VERY BRIEF MORNING TROPICAL SHOWERS APPEAR POSSIBLE ALONG THE COAST MAINLY IN THE MORNING. AFTERNOON CONVECTION SHOULD BE ISOLATED AT BEST DUE TO THE MID LEVEL DRYING...AND MAY STAY WEST OF THE FORECAST AREA ALTOGETHER. AN UPPER LOW WILL BE APPROACHING IN THE EASTERLY FLOW AND MODEL SPREAD IS CONSIDERABLE WITH NOT ONLY THE TRACK OF THIS SYSTEM BUT ALSO WHETHER OR NOT IT HAS ANY SURFACE REFLECTION. MODELS HAVE SLOWED WITH ITS PROGRESSION AND IT NOW LOOKS LIKE IT WILL STAY EAST OF THE REGION DURING THE SHORT TERM...IF IT AFFECTS US AT ALL. SUNDAY WILL THUS END UP VERY SIMILAR TO SATURDAY AS FAR AS RAIN DISTRIBUTION AND CHANCES. GUIDANCE SHOWING SUNDAY AFTERNOON TURNING OUT A LITTLE WARMER THAN SAT BUT NOT SO MUCH AS PREV FCST SO A SMALL TWEAK WAS MADE THERE. && .LONG TERM /MONDAY THROUGH THURSDAY/... AS OF 3 AM FRIDAY...BARRING ANY SIGNIFICANT WEATHER RESULTING FROM THE UPPER LOW COMING FROM THE EAST THE LONG TERM LOOKS VERY QUIET. AFOREMENTIONED LOW MAY RECURVE FROM THE COAST OR CONTINUE WESTWARD OVER LAND...MODELS AREN`T TOO SURE. OTHERWISE MID LEVEL FLOW WILL BE LIGHT AND VARIABLE AND THE WEST ATLANTIC HIGH WILL SHOW LITTLE MOVEMENT. MOISTURE RETURN LOOKS WEAK BUT SOME ISOLATED DIURNAL CONVECTION STILL SEEMS LIKELY EACH DAY. TEMPERATURES WILL BE RIGHT WHERE THEY SHOULD BE FOR THE TIME OF YEAR. && .AVIATION /06Z FRIDAY THROUGH TUESDAY/... AS OF 06Z...PERIODS OF MVFR/IFR OVERNIGHT DUE FOG/STRATUS THROUGH THE EARLY FRIDAY MORNING HRS. MORNING MVFR CONVECTION AT THE COASTAL TERMS...WILL EXPAND TO THE INLAND TERMS THIS AFTERNOON. FCST GUIDANCE/LATEST KLTX88D SUGGEST ADDITIONAL SHRA/TSRA TO DEVELOP OVER THE ADJACENT ATLANTIC WATERS EARLY THIS MORNING ...SPORADICALLY MOVING ONSHORE PRIOR TO SUNRISE. FOR NOW HAVE INTRODUCED VCSH. GIVEN ABUNDANT RAINFALL IN SOME LOCATIONS AND LIGHT AND VARIABLE WINDS...ANTICIPATE MVFR FOG...WITH MVFR/IFR LOW CIGS DUE TO STRATUS EARLY THIS MORNING. EXPECT ANY LINGERING FOG TO CLEAR OUT BY SEVERAL HRS AFTER SUNRISE. GUIDANCE DEPICTS CIGS BETWEEN 2000-3000FT AND ISOLATED/SCATTERED TSRA AT THE COAST AFTER SUNRISE...EXPANDING INLAND BY THE EARLY AFTERNOON. SYNOPTIC NE-E WINDS 5 KT OR LESS THIS MORNING WILL VEER TO THE SE 5 TO 10 KT... WITH GUSTS UP TO 15 KT AT THE COASTAL TERMS...BY MIDDAY. ANTICIPATE STORMS TO GRADUALLY TAPER OFF INTO THE LATE EVENING HOURS. EXTENDED OUTLOOK...A CHANCE OF THUNDERSTORMS EACH DAY...MAINLY IN THE AFTERNOON AND EVENING. OTHERWISE EXPECT VFR. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 1030 PM THURSDAY...THE FRONT INLAND HAS ACTUALLY SLID SOUTH AS A COLD FRONT TO NEAR CAPE FEAR LATE THIS EVENING. NORTHEAST WINDS ARE NOW BEING OBSERVED AT WRIGHTSVILLE BEACH AND AT THE WILMINGTON AIRPORT. WITH NO INCREASE IN SOUTHEASTERLY WINDS OFFSHORE EXPECTED THERE IS LITTLE REASON TO BELIEVE THE BOUNDARY WILL SUDDENLY SHIFT BACK TO THE NORTH OVERNIGHT...SO WE`VE ADJUSTED OUR WIND FORECAST TO SHOW EAST TO NORTHEAST FLOW NEAR AND NORTH OF CAPE FEAR OVERNIGHT. FORTUNATELY NO INCREASE IN WIND SPEEDS ARE EXPECTED. ANY OTHER CHANGES TO THE FORECAST ARE MINOR THIS EVENING. PREVIOUS DISCUSSION FROM 730 PM FOLLOWS... A WEAK FRONT STALLED ACROSS THE INLAND CAROLINAS HELPED FOCUS SHOWER AND THUNDERSTORM ACTIVITY THERE THIS AFTERNOON. ACROSS THE COASTAL WATERS A SOUTHEAST WIND AROUND 10 KT WILL CONTINUE THROUGH THE NIGHT. AS IS TYPICAL IN THESE TROPICAL AIRMASSES SCATTERED SHOWERS AND EVEN A FEW THUNDERSTORMS MAY DEVELOP ACROSS THE COASTAL WATERS OVERNIGHT IN THIS WARM AND HUMID REGIME. ACTIVITY SHOULD GENERALLY DRIFT TOWARD THE NORTH-NORTHWEST AND MAY BEGIN TO REACH THE BEACHES AFTER 3 AM ACCORDING TO THE LATEST RAPID-UPDATE HRRR COMPUTER MODEL. ALTHOUGH SEVERE WEATHER IS NOT EXPECTED BRIEFLY HEAVY RAINFALL AND THE POTENTIAL OF WATERSPOUTS WILL EXIST. AREA BUOYS SHOW 2-FOOT SEAS THIS EVENING WITH ALMOST ALL OF THE WAVE ENERGY EMBODIED IN A 9-SECOND SOUTHEAST SWELL. NO SIGNIFICANT CHANGE IS EXPECTED OVERNIGHT. SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... AS OF 3 AM FRIDAY..WEAK HIGH PRESSURE ACROSS THE WESTERN ATLANTIC ON SATURDAY WITH A SIMILARLY SUBTLE TROUGH WELL OFF THE COAST BY SUNDAY. THE LATTER WILL TILT FLOW FROM THE SOUTHEAST TO EAST OR EVEN NORTHEASTER WHILE SPEEDS REMAIN CAPPED AT JUST 10 KT. THE UPPER FEATURE DEVELOPING THIS TROUGH IS RATHER STRONG BY JULY STANDARDS AND COULD LEAD TO A SURFACE FEATURE STRONGER THAN CURRENTLY DEPICTED IN GUIDANCE. IF THIS TURNS OUT TO BE THE CASE THEN WINDS WILL BE A BIT HIGHER THAN FORECAST WITH A SIMILAR ADJUSTMENT MAYBE NEEDED FOR SEAS. OTHERWISE WAVES WILL STAY AT OR BELOW 3 FT. LONG TERM /MONDAY THROUGH TUESDAY/... AS OF 3 AM FRIDAY...SOUTHWEST WINDS GENERALLY IN THE 10 TO 15 KT RANGE AND SEAS AVERAGING 2 TO 4 FT THROUGH THE PERIOD...THE MOST COMMON SET OF CONDITIONS LOCALLY FOR THE SUMMER. HIGH PRESSURE ACROSS THE WEST ATLANTIC WILL BE FAIRLY WEAK. SWELL ENERGY PROGGED TO BE AROUND 10 SEC AND THE WIND CHOP 4-5 SECONDS. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...TRA SHORT TERM...MBB LONG TERM...MBB AVIATION...DCH/SGL
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
155 AM EDT FRI JUL 13 2012 .SYNOPSIS... A WEAK FRONT STALLED OVER THE CAROLINAS PLUS A HUMID TROPICAL AIRMASS WILL BRING A CONTINUING RISK OF SHOWERS AND THUNDERSTORMS THROUGH SATURDAY. A GRADUAL DRYING TREND WILL BEGIN SATURDAY AS BERMUDA HIGH PRESSURE STRENGTHENS OVER THE AREA. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1030 PM THURSDAY...THE FRONT HAS ACTUALLY PUSHED SOUTH THROUGH WILMINGTON...WHITEVILLE...CONWAY...MARION AND FLORENCE THIS EVENING WHERE WEAK NORTHEAST WINDS ARE NOW BEING OBSERVED. ABOVE AND AHEAD OF THE BOUNDARY NO INCREASE IN SOUTHEAST WINDS ARE EXPECTED SO THERE IS LITTLE REASON TO BELIEVE THE BOUNDARY WILL SUDDENLY SHIFT BACK TO THE THE NORTH. THERE IS LITTLE REAL AIRMASS DIFFERENCE ON EITHER SIDE OF THE FRONT SO IMPACTS ON SENSIBLE WEATHER (OTHER THAN WIND DIRECTION) ARE LIKELY TO BE MINOR. PREVIOUS DISCUSSION FROM 730 PM FOLLOWS... A STATIONARY FRONT ACROSS THE CAROLINAS IS OUTLINED ALONG A WEAK PRESSURE TROUGH AND BY A SHIFT FROM SOUTHEAST TO NORTHEAST WINDS. THE FRONT RUNS APPROXIMATELY FROM JACKSONVILLE NC ACROSS SOUTHERN DUPLIN AND SAMPSON COUNTIES TO NEAR FAYETTEVILLE...THEN SOUTHWESTWARD THROUGH BENNETTSVILLE AND DARLINGTON TO JUST NORTH OF COLUMBIA. THUNDERSTORMS IGNITED TODAY ALONG THIS FRONT AND ALSO ALONG THE SEABREEZE BOUNDARY...PUSHED SLOWLY NORTHWESTWARD BY THE 0-6 KM MEAN WIND. SURFACE-BASED INSTABILITY HAS BEEN NEARLY EXHAUSTED NOW WITH RADAR PRECIPITATION ESTIMATES SHOWING AT LEAST 80 PERCENT OF OUR FORECAST AREA RECEIVED SOME RAINFALL TODAY. INLAND CONVECTION SHOULD COMPLETELY DISSIPATE OVER THE NEXT 2 HOURS BUT PLENTY OF CONVECTIVE DEBRIS CLOUDINESS WILL REMAIN THROUGH THE NIGHT. ATTENTION THEN WILL SHIFT BACK TO THE COASTAL WATERS WHERE THE HRRR AND EVEN THE SYNOPTIC MODELS (GFS AND NAM) SHOW A RENEWED FOCUS FOR CONVECTION AFTER MIDNIGHT. THE STEERING FLOW WILL REMAIN ORIENTED ONSHORE MEANING WE WILL CONTINUE TO SHOW INCREASING PROBABILITIES FOR SHOWERS AND THUNDERSTORMS FOR THE COASTAL COUNTIES LATE TONIGHT. LOWS TONIGHT SHOULD REACH 70-75...WARMEST AT THE BEACHES. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... AS OF 230 PM THURSDAY..IT WILL TURN DECIDEDLY DRIER AS WE MOVE FROM FRI TO SAT WITH PRECIPITABLE WATER VALUES DROPPING FROM AROUND 2 INCHES FRI TO ONE AND A QUARTER INCHES DURING SAT. BERMUDA RIDGE WILL EXPAND FROM THE WESTERN ATLANTIC AND ACROSS THE EASTERN CAROLINAS THIS PERIOD...WITH A DEEP EASTERLY FLOW ENVELOPING THE AREA. FRI WILL BEGIN WITH AN INVERTED TROUGH NEAR OR AT THE COAST AND MOVING WESTWARD. THERE IS ALSO A SUBTLE FEATURE ALOFT BEING DEPICTED BY THE MODELS...MOVING WESTWARD DURING FRI. THIS COUPLED WITH THE SEABREEZE SHOULD BRING ANOTHER GOOD CHANCE OF SHOWERS AND THUNDERSTORMS TO COASTAL LOCATIONS DURING THE MORNING WITH POPS INCREASING INLAND AS THESE FEATURES MOVE INLAND DURING THE AFTERNOON WHILE LOWERING AT THE COAST. AT THIS TIME...WILL HOLD COVERAGE AT SCATTERED ALTHOUGH LOCALLY...COVERAGE MAY BECOME NUMEROUS. STORM MOTIONS AROUND 5 KT AND HIGH ATMOSPHERIC WATER CONTENT SHOULD YIELD SLOW MOVING THUNDERSTORMS WITH HEAVY DOWNPOURS. THIS MAY RESULT IN PONDING OF WATER IN LOW LYING AND POOR DRAINAGE AREAS. EXAMINATION OF OTHER PARAMETERS INDICATE THE RISK FOR SEVERE WEATHER IS OTHERWISE LOW AT THIS TIME. SAT...DRIER AIR AND DEVELOPING CAP AROUND 8-10 KFT...WILL NOT BE AN ENVIRONMENT CONDUCIVE FOR CONVECTION...EVEN ALONG THE SEABREEZE. WILL CONFINE POPS TO SMALL CHANCE AT THIS TIME. IT SHOULD BE NOTED THAT WITH THE DEVELOPING AND DEEPENING EASTERLY FLOW...NOCTURNAL SHOWERS DEVELOPING ACROSS THE CLIMATOLOGICALLY FAVORED WATERS MAY MOVE ONSHORE OVERNIGHT/EARLY MORNING HOURS AND THIS SEEMS MOST PLAUSIBLE LATE FRI NIGHT AND SAT MORNING. TEMPS WILL NOT DEVIATE MUCH FROM NORMAL VALUES FOR MID JULY...WITH HIGHS AND LOWS GENERALLY STAYING WITHIN A DEG OR TWO OF NORMAL. && .LONG TERM /SUNDAY THROUGH THURSDAY/... AS OF 250 PM THURSDAY...RETURN FLOW WILL CONTINUE AROUND BERMUDA HIGH THROUGH THE PERIOD. LOCAL AREA WILL REMAIN ON THE WESTERN PERIPHERY OF THE RIDGE WITH DEEPER S-SW RETURN FLOW THROUGH THE LOW LEVELS OF THE ATMOSPHERE. A MINOR PERTURBATION IN THE FLOW MAY RIDE THROUGH FROM THE EAST SUN INTO MON WITH INCREASED CHC OF PCP...BUT BASICALLY EXPECT DRIER MORE SUBSIDENT CONDITIONS THROUGH THE MID TO UPPER LEVELS THROUGH MOST OF THE PERIOD. OVERALL EXPECT MORE TYPICAL SUMMERTIME WEATHER WITH CU BUILDING EACH AFTERNOON AND CONVECTION POSSIBLE MAINLY ALONG SEA BREEZE AND FURTHER INLAND ALONG PIEDMONT TROUGH. AS RIDGE GETS SUPPRESSED A BIT FURTHER SOUTH HEADING LATE MON THROUGH MID WEEK...A BETTER WESTERLY COMPONENT TO THE FLOW WILL DEVELOP THROUGH THE LOW LEVELS. THIS SHOULD HELP TO PRODUCE A SLIGHT WARMING TREND. MAX TEMPS WILL REACH BETWEEN 90 AND 95 MOST DAYS AND REMAIN IN THE 70S OVERNIGHT. AT THE VERY END OF PERIOD MAY SEE NORTHERN STREAM SHORTWAVE DIG DOWN INTO THE CAROLINAS AND PUSH A FRONT THROUGH LATE THURS INTO FRI. THIS WOULD PRODUCE MORE WIDESPREAD CONVECTION BUT TOO FAR OUT TO FEEL CONFIDENT. && .AVIATION /06Z FRIDAY THROUGH TUESDAY/... AS OF 06Z...PERIODS OF MVFR/IFR OVERNIGHT DUE FOG/STRATUS THROUGH THE EARLY FRIDAY MORNING HRS. MORNING MVFR CONVECTION AT THE COASTAL TERMS...WILL EXPAND TO THE INLAND TERMS THIS AFTERNOON. FCST GUIDANCE/LATEST KLTX88D SUGGEST ADDITIONAL SHRA/TSRA TO DEVELOP OVER THE ADJACENT ATLANTIC WATERS EARLY THIS MORNING ...SPORADICALLY MOVING ONSHORE PRIOR TO SUNRISE. FOR NOW HAVE INTRODUCED VCSH. GIVEN ABUNDANT RAINFALL IN SOME LOCATIONS AND LIGHT AND VARIABLE WINDS...ANTICIPATE MVFR FOG...WITH MVFR/IFR LOW CIGS DUE TO STRATUS EARLY THIS MORNING. EXPECT ANY LINGERING FOG TO CLEAR OUT BY SEVERAL HRS AFTER SUNRISE. GUIDANCE DEPICTS CIGS BETWEEN 2000-3000FT AND ISOLATED/SCATTERED TSRA AT THE COAST AFTER SUNRISE...EXPANDING INLAND BY THE EARLY AFTERNOON. SYNOPTIC NE-E WINDS 5 KT OR LESS THIS MORNING WILL VEER TO THE SE 5 TO 10 KT... WITH GUSTS UP TO 15 KT AT THE COASTAL TERMS...BY MIDDAY. ANTICIPATE STORMS TO GRADUALLY TAPER OFF INTO THE LATE EVENING HOURS. EXTENDED OUTLOOK...A CHANCE OF THUNDERSTORMS EACH DAY...MAINLY IN THE AFTERNOON AND EVENING. OTHERWISE EXPECT VFR. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 1030 PM THURSDAY...THE FRONT INLAND HAS ACTUALLY SLID SOUTH AS A COLD FRONT TO NEAR CAPE FEAR LATE THIS EVENING. NORTHEAST WINDS ARE NOW BEING OBSERVED AT WRIGHTSVILLE BEACH AND AT THE WILMINGTON AIRPORT. WITH NO INCREASE IN SOUTHEASTERLY WINDS OFFSHORE EXPECTED THERE IS LITTLE REASON TO BELIEVE THE BOUNDARY WILL SUDDENLY SHIFT BACK TO THE NORTH OVERNIGHT...SO WE`VE ADJUSTED OUR WIND FORECAST TO SHOW EAST TO NORTHEAST FLOW NEAR AND NORTH OF CAPE FEAR OVERNIGHT. FORTUNATELY NO INCREASE IN WIND SPEEDS ARE EXPECTED. ANY OTHER CHANGES TO THE FORECAST ARE MINOR THIS EVENING. PREVIOUS DISCUSSION FROM 730 PM FOLLOWS... A WEAK FRONT STALLED ACROSS THE INLAND CAROLINAS HELPED FOCUS SHOWER AND THUNDERSTORM ACTIVITY THERE THIS AFTERNOON. ACROSS THE COASTAL WATERS A SOUTHEAST WIND AROUND 10 KT WILL CONTINUE THROUGH THE NIGHT. AS IS TYPICAL IN THESE TROPICAL AIRMASSES SCATTERED SHOWERS AND EVEN A FEW THUNDERSTORMS MAY DEVELOP ACROSS THE COASTAL WATERS OVERNIGHT IN THIS WARM AND HUMID REGIME. ACTIVITY SHOULD GENERALLY DRIFT TOWARD THE NORTH-NORTHWEST AND MAY BEGIN TO REACH THE BEACHES AFTER 3 AM ACCORDING TO THE LATEST RAPID-UPDATE HRRR COMPUTER MODEL. ALTHOUGH SEVERE WEATHER IS NOT EXPECTED BRIEFLY HEAVY RAINFALL AND THE POTENTIAL OF WATERSPOUTS WILL EXIST. AREA BUOYS SHOW 2-FOOT SEAS THIS EVENING WITH ALMOST ALL OF THE WAVE ENERGY EMBODIED IN A 9-SECOND SOUTHEAST SWELL. NO SIGNIFICANT CHANGE IS EXPECTED OVERNIGHT. SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... AS OF 230 PM THURSDAY...HIGH PRESSURE WILL DOMINATE THE MARINE ENVIRONMENT. A WEAK INVERTED TROUGH IS EXPECTED TO DEVELOP AND PERSIST THROUGH AT LEAST THE FIRST PART OF FRI...BUT THIS FEATURE WILL BE LOCATED MAINLY W OF THE WATERS. SE TO ESE WINDS ON FRI WILL BACK TO A MORE EASTERLY DIRECTION ON SAT. WIND SPEEDS ARE NOT EXPECTED TO EXCEED 15 KT. AN ESE SWELL IS EXPECTED TO INCREASE THROUGH THE PERIOD. THE SWELL WILL LENGTHEN FROM 7 SECONDS TO 9 SECONDS. THIS SWELL WILL ALLOW OVERALL SEAS TO BUILD FROM 2 TO 3 FT FRI TO 3 TO 4 FT SAT. LONG TERM /SUNDAY THROUGH TUESDAY/... AS OF 250 PM THURSDAY...EXPECT SOUTHERLY RETURN FLOW AROUND BERMUDA HIGH THROUGH THE PERIOD. AS HIGH BECOMES SUPPRESSED A BIT FURTHER SOUTH MON INTO TUES EXPECT S-SE WINDS TO VEER AROUND BECOMING MORE S TO SW. OVERALL SPEEDS SHOULD BE AROUND 10 KTS INCREASING SLIGHTLY AND BECOMING A BIT GUSTY EACH AFTERNOONS IN SEA BREEZE. THIS PERSISTENT SOUTHERLY PUSH WILL KEEP SEAS AROUND 2 TO 4 FT THROUGH THE PERIOD. WNA SHOWS LONGER PERIOD 9 TO 10 SECOND E-SE SWELL MIXING WITH LOCALLY DRIVEN WIND WAVES THROUGH THE PERIOD. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...TRA SHORT TERM...RJD LONG TERM...RGZ AVIATION...DCH/SGL
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
908 PM CDT SAT JUL 14 2012 .DISCUSSION... MAIN CHANGES FOR THE EVENING UPDATE WERE TO TWEAK POPS A BIT. SOME LIGHT RADAR RETURNS HAVE ENTERED THE FAR NORTHWESTERN CWA. NOT MUCH CAME DOWN FROM THIS AS IT WAS CROSSING THE CENTRAL AND WESTERN PORTIONS OF THE STATE...BUT A FEW LOCATIONS REPORTED BRIEF -RA UNDER THE HEAVIER RETURNS. THINK THAT THE ACTIVITY IS MOSTLY MID LEVEL AND JUST INCLUDED AN ISOLATED SPRINKLE MENTION IN THAT AREA FOR NOW. MORE SIGNIFICANT PRECIP IS OUT WEST STRETCHING FROM NEAR GARRISON TO WILLIS TON AND MOVING NORTHEASTWARD WITH A WEAK SHORTWAVE COMING THROUGH. THINK THAT MOST OF THE ACTIVITY WILL MOVE OFF INTO CANADA TO OUR WEST...BUT THERE IS THE POSSIBILITY OF A FEW OF THE NORTHWESTERN COUNTIES GETTING CLIPPED AFTER MIDNIGHT. THREW IN SOME 30 POPS FOR THE WESTERN PORTIONS OF DEVILS LAKE BASIN. HRRR RUNS HAVE BEEN REALLY OVERDOING CONVECTION BUT NAM SEEMS TO BE UNDERDONE...SO WENT A BIT IN BETWEEN. LEFT LOWS IN THE 60S TO LOW 70S. && .AVIATION... VFR CONDITIONS WILL CONTINUE THROUGHOUT THE PERIOD WITH SLOWLY LOWERING HIGH AND MID CLOUDS. NOT ENOUGH CERTAINTY WITH CONVECTION TO INCLUDE IT WITH THE TAF SITES AT THIS POINT...BUT IF ANYTHING OCCURS IT WILL BE OUT AROUND KDVL. LIGHT AND VARIABLE WINDS TONIGHT WILL BEGIN TO PICK UP OUT OF THE EAST AND SOUTHEAST BY TOMORROW...WITH SOME GUSTS UP AROUND 20 KTS POSSIBLE IN THE AFTERNOON. && .PREV DISCUSSION... /ISSUED 328 PM CDT SAT JUL 14 2012/ SHORT TERM...TONIGHT THROUGH TUESDAY PRIMARY FORECAST CHALLENGE WILL BE TEMPERATURES AND PRECIPITATION CHANCES ON SUNDAY. GFS/NAM/ECMWF/GEM MASS FIELDS ARE IN REASONABLE AGREEMENT...BUT THERE EXIST SIGNIFICANT DIFFERENCES IN THE LOW- LEVEL THERMAL AND MOISTURE PROFILES. THE GFS IS TOO MOIST AND A BIT COOL...THE NAM IS TOO DRY AND DOWNRIGHT HOT...AND THE ECMWF IS SOMEWHERE IN-BETWEEN. WILL LEAN ON THE ECMWF SOLUTION FOR TEMPERATURES AND PRECIPITATION PLACEMENT. LATE THIS AFTERNOON AND EVENING...THERMAL CU ACROSS NORTHWEST AND WEST CENTRAL MN WILL DISSIPATE QUICKLY AFTER SUNSET WHILE MID-HIGH LEVEL CLOUDS INCREASE FROM THE WEST. ROGUE THUNDERSTORM THAT INITIATED OFF THE SOUTHERN SHORE OF LOWER RED LAKE EARLIER THIS AFTERNOON QUICKLY DISSIPATED AND DO NOT EXPECT FURTHER CONVECTIVE DEVELOPMENT. OVERNIGHT LOWS WILL BE IN THE 60S TO NEAR 70 DEGREES GIVEN CLOUD COVER AND LIGHT SOUTHEAST WIND. REGIONAL RADARS SHOWING SOME ECHOES ACROSS NORTHWEST ND THIS AFTERNOON...BUT NEARBY SURFACE OBSERVATIONS NOT REPORTING ANY RAIN AND CLOUD BASES ARE 10 KFT OR HIGHER. WILL HOLD OFF ON PRECIPITATION UNTIL SUNDAY MORNING. FOR SUNDAY...SURFACE LOW/TROUGH ACROSS EASTERN MT WILL DRIFT ACROSS ND THROUGH THE DAY AND REACH THE RED RIVER VALLY BY 12 UTC MONDAY MORNING. 700 HPA TEMPERATURES INCREASE FROM +10 TO +12 C... EFFECTIVELY CAPPING THE LOWER ATMOSPHERE. SCATTERED SHOWERS AND STORMS ARE POSSIBLE MAINLY ACROSS THE DEVILS LAKE BASIN AND NORTHERN VALLEY IN ASSOCIATION WITH MID-LEVEL WARM AIR ADVECTION AHEAD OF THE CAP...BUT MOST OF THE DAY SHOULD BE DRY. BEING IN THE SYSTEM/S WARM SECTOR WITH 925 HPA TEMPERATURES IN THE +20 TO +25 C RANGE...AFTERNOON HIGHS WILL SOAR INTO THE LOWER TO MID 90S ACROSS MUCH OF EASTERN ND. WITH DEW POINTS IN THE MID TO UPPER 60S...HEAT INDEX VALUES APPROACH 100 DEGREES IN ISOLATED SPOTS ACROSS SOUTHEAST ND. WILL HOLD OFF ON A HEAT ADVISORY FOR NOW...BUT LATER SHIFTS MAY NEED TO RECONSIDER IF SURFACE MOISTURE INCREASES MORE THAN CURRENTLY FORECAST. SUNDAY WILL BE LOCALLY BREEZY WITH SOUTH- SOUTHEAST WIND FROM 15 TO 20 MPH. CONVECTIVE CHANCES INCREASE LATE SUNDAY AFTERNOON AND EVENING AS SURFACE TROUGH APPROACHES FROM THE WEST AND 850 HPA LOW-LEVEL JET INCREASES TO 40 KTS BY 06 UTC MONDAY. IF MOISTURE CAN POOL ALONG THE BOUNDARY AND THE MID-LEVEL CAP IS BROKEN...THERE IS 1000 TO 3000 J/KG OF MLCAPE AND 30 TO 50 KTS OF BULK SHEAR FOR CONVECTIVE INITIATION. SPC DAY TWO CONVECTIVE OUTLOOK PAINTS A SLIGHT RISK FOR SEVERE STORMS ACROSS THE DEVILS LAKE BASIN IF CONVECTIVE PARAMETERS ALIGN. TOO MANY IFS AT THIS POINT TO ADD SEVERE MENTION TO THE GRIDS...BUT SOMETHING TO WATCH. BEST CHANCE FOR CONVECTION WILL BE ALONG AND NORTH OF THE INTERNATIONAL BORDER SUNDAY NIGHT AS ALL MODELS SUGGEST SOME KIND OF CONVECTIVE COMPLEX DEVELOPING ALONG THE MID-LEVEL WARM FRONT. GFS IS TOO FAR SOUTH WITH THIS COMPLEX...WHICH MAY BE DUE TO ITS ANOMALOUSLY HIGH LOW-LEVEL MOISTURE. THE ECMWF PAINTS THE HIGHEST QPF JUST NORTH OF THE BORDER. WILL TRIM 60 POPS BACK A BIT...BUT LEAVE A SLIVER ACROSS THE NORTHERN TIER COUNTIES. CHANCE POPS WILL EXTEND SOUTH TO THE HIGHWAY 200 CORRIDOR WITH NO PRECIPITATION EXPECTED ACROSS SOUTHEAST ND INTO WEST CENTRAL MN. SOME LINGERING SHOWERS AND THUNDERSTORMS ARE POSSIBLE ON MONDAY BEFORE DRYING OUT ON TUESDAY. COOLER AIRMASS DROPS BEHIND DEPARTING SYSTEM ON MONDAY WITH SLIGHTLY LOWER TEMPERATURES... NEARING SEASONAL AVERAGES FOR THE FIRST TIME IN DAYS BY TUESDAY. LONG TERM...TUESDAY NIGHT THROUGH SATURDAY THE GFS CONTINUES TO BE OVERDONE WITH QPF...AND PREFER THE DRIER/WARMER ECMWF. THE BEST CHANCE FOR SOME CONVECTION SHOULD BE WED NIGHT AND THU AS A WAVE TRIES TO BREAK DOWN THE RIDGE ALOFT AND WILL MENTION SOME LOWER POPS. WOULD NOT BE SURPRISED TO SEE MINIMAL PRECIP EVEN ON THU WITH THE DRY/WARM PATTERN CONTINUING. OTHERWISE...EXPECT A DRY EXTENDED WITH TEMPS STARTING THE PERIOD NEAR NORMAL AND WARMING ABOVE NORMAL BY THE END OF THE WEEK. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ JR
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1142 PM EDT SAT JUL 14 2012 .SYNOPSIS... A MOISTURE BOUNDARY WILL TRIGGER SHOWERS AND THUNDERSTORMS SUNDAY AND BRING DRIER AIR OVER THE REGION SUNDAY NIGHT INTO MONDAY. A SURGE OF WARM AIR AHEAD OF A COLD FRONT WILL BRING VERY WARM AIR INTO PENNSYLVANIA TUESDAY INTO WEDNESDAY. AS THE UPPER RIDGE RETROGRADES TUESDAY THROUGH FRIDAY A TROUGH WILL DEVELOP OVER THE NORTHEAST. THIS SHOULD PUSH COOLER AND DRIER AIR INTO OUR REGION LATE WEDNESDAY INTO THURSDAY. IT SHOULD BE COOLER AND DRIER THURSDAY THROUGH SATURDAY. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... MOST OF THE REGION HAS REMAINED RAIN FREE TONIGHT. RADAR AND ONE SPOTTER REPORT SUGGEST OVER 2 INCHES OF RAIN HAS FALLEN IN SOUTHERN SOMERSET COUNTY. RADAR AND SATELLITE SHOW SHOWERS AND STORMS OVER WEST VIRGINIA TRYING TO MOVE INTO SOUTHWESTERN PENNSYLVANIA. THE HRRR AND NAM4KM SUGGEST ANY SHOWERS SHOULD ARC MORE ANTICYCLONICALLY AS THEY MOVE INTO PA. THIS COULD LIMIT THE NORTHERN EXTENT OF THE RAIN TONIGHT. THOUGH BOTH SHOW A NEW AREA DEVELOP OVER NORTHERN PA AROUND 0600 UTC. DESPITE THIS THERE IS ONE STRAY STORM WALKING ACROSS ARMSTRONG AND INDIANA COUNTIES WHICH COULD BRING RAIN TO CLEARFIELD COUNTY. THE STORMS IN SOMERSET COUNTY ARE VERY SLOW MOVING TOO. BIASED POPS EARLY WITH RADAR AND LATER HALF OF OVERNIGHT WITH SREF WHICH HAD LOWER POPS. HARD TO CHASE HOURLY HRRR RUNS. BUT BUMPED UP POPS ALONG NY BORDER. TEMPS CLOSE TO GUIDANCE. LOW 60S NORTH NEAR 70 IN URBAN AREAS IN SOUTHEAST. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/... VERY WARM HUMID DAY AS A BOUNDARY APPROACHES FROM THE NW. NOT MUCH OF A FRONT AS IT HAS BEEN WARM TO OUR NORTH BENEATH THE ANOMALOUSLY HIGH HEIGHTS TO OUR NORTH. THE PW VALUE PEAK OVER PA TOMORROW AHEAD OF THIS BOUNDARY...THIS COULD TRIGGER MORE ORGANIZED SHOWERS AND T-STORMS. THERE IS SOME ENHANCED WINDS AT 850 AND 700 HPA SO THERE COULD BE SOME STRONG GUSTS IN ANY STORMS WHICH DEVELOP. THE LOWER PW VALUE BEHIND THE BOUNDARY SHOULD MOVE NORTHWEST TO SOUTHEAST ACROSS THE STATE LATE SUNDAY. THE HUMIDITY DROP SUNDAY EVENING INTO MONDAY SHOULD BE SIGNIFICANT. BUT IT WILL BE HOT AND HUMID AHEAD OF THIS FEATURE ON SUNDAY. && .LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/... BUMPED UP TEMPERATURES MONDAY AND LOWERED POPS OVERNIGHT SUNDAY INTO MONDAY. PREVIOUS DISCUSSION: A WEAK TROF IN THE GENERALLY WESTERLY FLOW WILL BE EXITING TO THE EAST AT THE START OF THE PERIOD. A RISE IN HEIGHTS BEHIND THE TROF WILL BE SHORT LIVED AS A NORTHERN STREAM UPPER TROF/LOW CENTER IS FORECAST TO COME TO A HALT OVER NORTHERN QUEBEC BY MID WEEK. THIS WILL LEAD TO STEADILY FALLING HEIGHTS OVER THE NEW ENGLAND AND THE MID ATLANTIC STATES....AND THE PASSAGE OF A COLD FRONT AROUND MID WEEK. AHEAD OF THE FRONT ANOTHER HOT SPELL LOOKS IN THE OFFING WITH A DISTINCT COOLING OFF/DRYING OUT PERIOD LATE IN THE WEEK BEHIND THE FRONT. MINS AT DAYBREAK MONDAY WILL BE ABOVE NORMAL...VARYING FROM THE LOWER TO MID 60S ACROSS THE MTNS...TO UPPER 60S TO AROUND 70 DEGREES ELSEWHERE. FOR MONDAY...A SFC RIDGE OF HIGH PRESSURE EXTENDING NE ALONG THE APPALACHIANS...AND FLAT RIDGING SLIDING SOUTHEAST ALOFT WILL SUPPLY US WITH A PARTLY TO MOSTLY SUNNY...HOT AND HUMID MONDAY. LATER SHIFTS WILL NEED TO KEEP AN EYE ON POTENTIAL HEAT INDICES CLIMBING TO AROUND 100-102 IN THE LOWER SUSQ VALLEY SHOULD TEMPS AND SFC DEWPOINTS TURN OUT TO BE ANOTHER FEW DEGREES HIGHER. CURRENTLY... HEAT INDICES IN THAT AREA ARE FORECAST TO BE IN THE LOW-MID 90S. ISOLATED TO SCTD AFTERNOON AN EVENING TSRA ARE POSSIBLE ALONG THE LEE TROUGH THAT SHOULD RESIDE ACROSS OUR FAR SERN ZONES MONDAY. MINIMAL CHANCES FOR RAIN CONTINUE FOR MOST OF THE CENTRAL AND EASTERN PORTIONS OF THE CWA ON TUESDAY...AS A MID LEVEL THERMAL RIDGE CRESTING THE AREA HELPS TO CAP OFF THE MAJORITY OF CONVECTION. THE PEAK IN THE UPCOMING...SHORT-LIVED HEAT WAVE WILL BE TUESDAY WHEN 850 TEMPS VIA THE 00Z GEFS CLIMB TO AROUND PLUS 2 ST DEVIATIONS OR 20-22C. THIS WILL TRANSLATE INTO MAX TEMPS IN THE U80S ACROSS THE HIGHER TERRAIN OF THE NORTH AND WEST...AND LOWER TO MID 90S THROUGHOUT THE CENTRAL AND SE VALLEYS. DEEP LAYER...WEST TO NWRLY SHEAR INCREASES WEDNESDAY AS A POTENT UPPER TROUGH AND SFC COLD FRONT PUSHES SE FROM THE GLAKES REGION. A ROUND OR TWO OF GUSTY TSRA IS POSSIBLE WITH THIS FRONTAL PASSAGE. TO CLOSE OUT THE WEEK...A REFRESHINGLY DRIER AND RELATIVELY COOLER AIRMASS WILL OVERSPREAD THE STATE AS A DEEP UPPER LOW SLIDES ACROSS EASTERN CANADA WITH STRONG NW FLOW ALOFT OVER THE GREAT LAKES AND NERN U.S.. DRY DEWPOINTS IN THE U40S TO 50S WILL SUPPORT COOL COMFORTABLE NIGHTS WEDNESDAY NIGHT THROUGH FRIDAY NIGHT. && .AVIATION /04Z SUNDAY THROUGH THURSDAY/... MORE IN THE WAY OF SHOWERS AND STORMS MOVING INTO SW PA... ADJUSTED 03Z TAFS. EXPECT CONDITIONS TO IMPROVE BY LATE SUNDAY MORNING...AS WINDS SHIFT MORE TO THE WEST. WINDS MAY BE GUSTY AS INTENSE JULY SUN WARMS THINGS UP. BEST CHC FOR A GUSTY THUNDERSTORM WILL BE ALONG THE LEE SIDE TROUGH. OUTLOOK... MON...MAINLY VFR BUT WITH ISOLATED SHOWERS/STORMS PSBL. TUE...VFR/NO SIG WX. WED...SCT TSTM IMPACTS PSBL. THU...ISOLATED SHWR PSBL ACROSS S PA EARLY... OTHERWISE VFR. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...GRUMM NEAR TERM...GRUMM/LA CORTE/MARTIN SHORT TERM...GRUMM/LA CORTE LONG TERM...LAMBERT/GARTNER AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1026 PM EDT SAT JUL 14 2012 .SYNOPSIS... A MOISTURE BOUNDARY WILL TRIGGER SHOWERS AND THUNDERSTORMS SUNDAY AND BRING DRIER AIR OVER THE REGION SUNDAY NIGHT INTO MONDAY. A SURGE OF WARM AIR AHEAD OF A COLD FRONT WILL BRING VERY WARM AIR INTO PENNSYLVANIA TUESDAY INTO WEDNESDAY. AS THE UPPER RIDGE RETROGRADES TUESDAY THROUGH FRIDAY A TROUGH WILL DEVELOP OVER THE NORTHEAST. THIS SHOULD PUSH COOLER AND DRIER AIR INTO OUR REGION LATE WEDNESDAY INTO THURSDAY. IT SHOULD BE COOLER AND DRIER THURSDAY THROUGH SATURDAY. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... MOST OF THE REGION HAS REMAINED RAIN FREE TONIGHT. RADAR AND ONE SPOTTER REPORT SUGGEST OVER 2 INCHES OF RAIN HAS FALLEN IN SOUTHERN SOMERSET COUNTY. RADAR AND SATELLITE SHOW SHOWERS AND STORMS OVER WEST VIRGINIA TRYING TO MOVE INTO SOUTHWESTERN PENNSYLVANIA. THE HRRR AND NAM4KM SUGGEST ANY SHOWERS SHOULD ARC MORE ANTICYCLONICALLY AS THEY MOVE INTO PA. THIS COULD LIMIT THE NORTHERN EXTENT OF THE RAIN TONIGHT. THOUGH BOTH SHOW A NEW AREA DEVELOP OVER NORTHERN PA AROUND 0600 UTC. DESPITE THIS THERE IS ONE STRAY STORM WALKING ACROSS ARMSTRONG AND INDIANA COUNTIES WHICH COULD BRING RAIN TO CLEARFIELD COUNTY. THE STORMS IN SOMERSET COUNTY ARE VERY SLOW MOVING TOO. BIASED POPS EARLY WITH RADAR AND LATER HALF OF OVERNIGHT WITH SREF WHICH HAD LOWER POPS. HARD TO CHASE HOURLY HRRR RUNS. BUT BUMPED UP POPS ALONG NY BORDER. TEMPS CLOSE TO GUIDANCE. LOW 60S NORTH NEAR 70 IN URBAN AREAS IN SOUTHEAST. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/... VERY WARM HUMID DAY AS A BOUNDARY APPROACHES FROM THE NW. NOT MUCH OF A FRONT AS IT HAS BEEN WARM TO OUR NORTH BENEATH THE ANOMALOUSLY HIGH HEIGHTS TO OUR NORTH. THE PW VALUE PEAK OVER PA TOMORROW AHEAD OF THIS BOUNDARY...THIS COULD TRIGGER MORE ORGANIZED SHOWERS AND T-STORMS. THERE IS SOME ENHANCED WINDS AT 850 AND 700 HPA SO THERE COULD BE SOME STRONG GUSTS IN ANY STORMS WHICH DEVELOP. THE LOWER PW VALUE BEHIND THE BOUNDARY SHOULD MOVE NORTHWEST TO SOUTHEAST ACROSS THE STATE LATE SUNDAY. THE HUMIDITY DROP SUNDAY EVENING INTO MONDAY SHOULD BE SIGNIFICANT. BUT IT WILL BE HOT AND HUMID AHEAD OF THIS FEATURE ON SUNDAY. && .LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/... BUMPED UP TEMPERATURES MONDAY AND LOWERED POPS OVERNIGHT SUNDAY INTO MONDAY. PREVIOUS DISCUSSION: A WEAK TROF IN THE GENERALLY WESTERLY FLOW WILL BE EXITING TO THE EAST AT THE START OF THE PERIOD. A RISE IN HEIGHTS BEHIND THE TROF WILL BE SHORT LIVED AS A NORTHERN STREAM UPPER TROF/LOW CENTER IS FORECAST TO COME TO A HALT OVER NORTHERN QUEBEC BY MID WEEK. THIS WILL LEAD TO STEADILY FALLING HEIGHTS OVER THE NEW ENGLAND AND THE MID ATLANTIC STATES....AND THE PASSAGE OF A COLD FRONT AROUND MID WEEK. AHEAD OF THE FRONT ANOTHER HOT SPELL LOOKS IN THE OFFING WITH A DISTINCT COOLING OFF/DRYING OUT PERIOD LATE IN THE WEEK BEHIND THE FRONT. MINS AT DAYBREAK MONDAY WILL BE ABOVE NORMAL...VARYING FROM THE LOWER TO MID 60S ACROSS THE MTNS...TO UPPER 60S TO AROUND 70 DEGREES ELSEWHERE. FOR MONDAY...A SFC RIDGE OF HIGH PRESSURE EXTENDING NE ALONG THE APPALACHIANS...AND FLAT RIDGING SLIDING SOUTHEAST ALOFT WILL SUPPLY US WITH A PARTLY TO MOSTLY SUNNY...HOT AND HUMID MONDAY. LATER SHIFTS WILL NEED TO KEEP AN EYE ON POTENTIAL HEAT INDICES CLIMBING TO AROUND 100-102 IN THE LOWER SUSQ VALLEY SHOULD TEMPS AND SFC DEWPOINTS TURN OUT TO BE ANOTHER FEW DEGREES HIGHER. CURRENTLY... HEAT INDICES IN THAT AREA ARE FORECAST TO BE IN THE LOW-MID 90S. ISOLATED TO SCTD AFTERNOON AN EVENING TSRA ARE POSSIBLE ALONG THE LEE TROUGH THAT SHOULD RESIDE ACROSS OUR FAR SERN ZONES MONDAY. MINIMAL CHANCES FOR RAIN CONTINUE FOR MOST OF THE CENTRAL AND EASTERN PORTIONS OF THE CWA ON TUESDAY...AS A MID LEVEL THERMAL RIDGE CRESTING THE AREA HELPS TO CAP OFF THE MAJORITY OF CONVECTION. THE PEAK IN THE UPCOMING...SHORT-LIVED HEAT WAVE WILL BE TUESDAY WHEN 850 TEMPS VIA THE 00Z GEFS CLIMB TO AROUND PLUS 2 ST DEVIATIONS OR 20-22C. THIS WILL TRANSLATE INTO MAX TEMPS IN THE U80S ACROSS THE HIGHER TERRAIN OF THE NORTH AND WEST...AND LOWER TO MID 90S THROUGHOUT THE CENTRAL AND SE VALLEYS. DEEP LAYER...WEST TO NWRLY SHEAR INCREASES WEDNESDAY AS A POTENT UPPER TROUGH AND SFC COLD FRONT PUSHES SE FROM THE GLAKES REGION. A ROUND OR TWO OF GUSTY TSRA IS POSSIBLE WITH THIS FRONTAL PASSAGE. TO CLOSE OUT THE WEEK...A REFRESHINGLY DRIER AND RELATIVELY COOLER AIRMASS WILL OVERSPREAD THE STATE AS A DEEP UPPER LOW SLIDES ACROSS EASTERN CANADA WITH STRONG NW FLOW ALOFT OVER THE GREAT LAKES AND NERN U.S.. DRY DEWPOINTS IN THE U40S TO 50S WILL SUPPORT COOL COMFORTABLE NIGHTS WEDNESDAY NIGHT THROUGH FRIDAY NIGHT. && .AVIATION /02Z SUNDAY THROUGH THURSDAY/... EXPECT MORE IN THE WAY OF SHOWERS LATER TONIGHT...ALONG WITH MORE IN THE WAY OF LOW CIGS AND FOG. HOWEVER...STILL NOT SEEING OR EXPECTING A LARGE AMT OF ADVERSE WEATHER. EXPECT CONDITIONS TO IMPROVE BY LATE SUNDAY MORNING...AS WINDS SHIFT MORE TO THE WEST. WINDS MAY BE GUSTY AS INTENSE JULY SUN WARMS THINGS UP. BEST CHC FOR A GUSTY THUNDERSTORM WILL BE ALONG THE LEE SIDE TROUGH. OUTLOOK... MON...MAINLY VFR BUT WITH ISOLATED SHOWERS/STORMS PSBL. TUE...VFR/NO SIG WX. WED...SCT TSTM IMPACTS PSBL. THU...ISOLATED SHWR PSBL ACROSS S PA EARLY... OTHERWISE VFR. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...GRUMM NEAR TERM...GRUMM/LA CORTE/MARTIN SHORT TERM...GRUMM/LA CORTE LONG TERM...LAMBERT/GARTNER AVIATION...LA CORTE/MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
742 PM EDT SAT JUL 14 2012 .SYNOPSIS... AN APPROACHING WARM FRONT WILL BRING INCREASINGLY MOIST AND UNSETTLED CONDITIONS TO THE REGION FOR THE REMAINDER OF THE WEEKEND. WARM AND HUMID WEATHER WILL CONTINUE THROUGH MIDWEEK BEFORE A COLD FRONT BRINGS DRIER AND A MORE COMFORTABLE AIRMASS FOR THE END OF THE WEEK. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... ISOLATED SHOWERS AND STORMS SOUTH OF INTERSTATE 80. MORE IN THE WAY OF WIDESPREAD ACTIVITY ACROSS NW OH AND SW OF PIT. ACTIVITY MAY INCREASE LATER TONIGHT...BUT NOT SEEING LOT OF POTENTIAL FOR WIDESPREAD ACTIVITY. MINOR CHANGES MADE TO THE PACKAGE. EARLIER DISCUSSION BELOW. CLOUDS APPEAR TO BE DIMINISHING A BIT OVER THE REGION...BUT THERE IS A GOOD MIX OF LOW...MID...AND HIGH CLOUDS SO CENTRAL AREAS WILL JUST SEE PEEKS OF SUN. MOSTLY SUNNY IN THE NORTHEASTERN AREAS AND A BIT OF A CLEAR SLOT MOVING INTO THE WEST. RADAR SHOWS SHOWER ACTIVITY ON THE WANE. ONLY TWO SHOWERS OF NOTE WELL TO OUR WEST. SO...LOWERED THE POPS THIS EVENING AND EARLY TONIGHT. ADDITIONALLY THE HRRR AND 4KM NAM SHOW SOME MAINLY RANDOM SHOWERS. THE 15Z SREF POPS ARE LOWER THAN THE 0900 UTC RUN. LOWERED THE POPS...BEST CHANCE IN WEST OVERNIGHT BASED ON SREF POPS AND ALL THE LIGHTNING ON THE SATELLITE IMAGERY OVER NORTHERN KY AND SOUTHERN OH. SOME OF THAT COULD BRING MORE CLOUDS AND RAIN TO SOUTHWESTERN AREAS OVERNIGHT. ANY STORMS THAT DEVELOP COULD EASILY PRODUCE 1-2 INCHES OF QPF. SREF SHOWS AREAS OF 30 PERCENT CHANCE OF 1 OR MORE INCHES. PW IS 45 T0 50 MM SO 1-2 INCHES SEEMS REASONABLE. HIGHEST PROBABILITY WOULD BE IN WESTERN THIRD OF PA OVERNIGHT. WOULD NOT KNOW IS WHERE UNTIL THE STORM/SHOWERS APPEARED ON RADAR. A BIT WARMER OVERNIGHT TONIGHT THAN LAST NIGHT TOO. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/... THE 15Z SREF WAS CAUSE TO LOWER POPS A BIT ON SUNDAY BUT STILL ALL SIGNALS POINT TO BEST CHANCE SHOWERS AND THUNDERSTORMS WOULD BE SUNDAY. THE HIGHER PW AIR IS PUSHING EAST SUNDAY SO THE WETTER SUSPECTS WOULD BE IN THE EAST. THE GOOD NEWS IS MOST AREAS ARE IN THE 50 TO 70 POPS RANGE IN MOST GUIDANCE AND DRIER AIR IS MOVING IN. THE WEATHER IN THE WEST COULD IMPROVE LATE IN THE AFTERNOON AND EVENING SUNDAY. DRY AIR IS GOING TO END OUR (BY SUNDAY AFTERNOON) 3 DAY MOSTLY CLOUDY HUMID PERIOD. PREVIOUS DISCUSSION HITS MOST OF THE POINTS : BASICALLY ALL THE GUIDANCE POINTS TO A NEAR CERTAINTY OF SEEING MEASURABLE RAIN OVER MOST OF THE REGION TOMORROW...ESPECIALLY IN THE AFTERNOON. MUCH NEEDED RAINFALL SHOULD AMOUNT TO BASIN AVERAGE AMOUNTS IN THE 0.25-0.50 RANGE ACROSS MUCH OF CENTRAL PENN. THE LIKELIHOOD OF LOCALIZED 1-2 INCH AMOUNTS EXISTS IN AREAS IMPACTED BY REPEAT SHOWERS/STORMS SUNDAY AFTERNOON AND EVENING. MAX TEMPS SUNDAY WILL BE HIGHLY DEPENDENT ON THE AMOUNT OF INSOLATION WE CAN GET THROUGH THE RATHER EXPANSIVE LAYERED MID CLOUD DECK. FCST HIGHS CURRENTLY RANGE FROM AROUND 80F ACROSS THE MTNS...TO A STEAMY 90 DEGREES ACROSS THE LOWER SUSQ VALLEY REGION. && .LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/... A WEAK TROF IN THE GENERALLY WESTERLY FLOW WILL BE EXITING TO THE EAST AT THE START OF THE PERIOD. A RISE IN HEIGHTS BEHIND THE TROF WILL BE SHORT LIVED AS A NORTHERN STREAM UPPER TROF/LOW CENTER IS FORECAST TO COME TO A HALT OVER NORTHERN QUEBEC BY MID WEEK. THIS WILL LEAD TO STEADILY FALLING HEIGHTS OVER THE NEW ENGLAND AND THE MID ATLANTIC STATES....AND THE PASSAGE OF A COLD FRONT AROUND MID WEEK. AHEAD OF THE FRONT ANOTHER HOT SPELL LOOKS IN THE OFFING WITH A DISTINCT COOLING OFF/DRYING OUT PERIOD LATE IN THE WEEK BEHIND THE FRONT. MINS AT DAYBREAK MONDAY WILL BE ABOVE NORMAL...VARYING FROM THE LOWER TO MID 60S ACROSS THE MTNS...TO UPPER 60S TO AROUND 70 DEGREES ELSEWHERE. FOR MONDAY...A SFC RIDGE OF HIGH PRESSURE EXTENDING NE ALONG THE APPALACHIANS...AND FLAT RIDGING SLIDING SOUTHEAST ALOFT WILL SUPPLY US WITH A PARTLY TO MOSTLY SUNNY...HOT AND HUMID MONDAY. LATER SHIFTS WILL NEED TO KEEP AN EYE ON POTENTIAL HEAT INDICES CLIMBING TO AROUND 100-102 IN THE LOWER SUSQ VALLEY SHOULD TEMPS AND SFC DEWPOINTS TURN OUT TO BE ANOTHER FEW DEGREES HIGHER. CURRENTLY... HEAT INDICES IN THAT AREA ARE FORECAST TO BE IN THE LOW-MID 90S. ISOLATED TO SCTD AFTERNOON AN EVENING TSRA ARE POSSIBLE ALONG THE LEE TROUGH THAT SHOULD RESIDE ACROSS OUR FAR SERN ZONES MONDAY. MINIMAL CHANCES FOR RAIN CONTINUE FOR MOST OF THE CENTRAL AND EASTERN PORTIONS OF THE CWA ON TUESDAY...AS A MID LEVEL THERMAL RIDGE CRESTING THE AREA HELPS TO CAP OFF THE MAJORITY OF CONVECTION. THE PEAK IN THE UPCOMING...SHORT-LIVED HEAT WAVE WILL BE TUESDAY WHEN 850 TEMPS VIA THE 00Z GEFS CLIMB TO AROUND PLUS 2 ST DEVIATIONS OR 20-22C. THIS WILL TRANSLATE INTO MAX TEMPS IN THE U80S ACROSS THE HIGHER TERRAIN OF THE NORTH AND WEST...AND LOWER TO MID 90S THROUGHOUT THE CENTRAL AND SE VALLEYS. DEEP LAYER...WEST TO NWRLY SHEAR INCREASES WEDNESDAY AS A POTENT UPPER TROUGH AND SFC COLD FRONT PUSHES SE FROM THE GLAKES REGION. A ROUND OR TWO OF GUSTY TSRA IS POSSIBLE WITH THIS FRONTAL PASSAGE. TO CLOSE OUT THE WEEK...A REFRESHINGLY DRIER AND RELATIVELY COOLER AIRMASS WILL OVERSPREAD THE STATE AS A DEEP UPPER LOW SLIDES ACROSS EASTERN CANADA WITH STRONG NW FLOW ALOFT OVER THE GREAT LAKES AND NERN U.S.. DRY DEWPOINTS IN THE U40S TO 50S WILL SUPPORT COOL COMFORTABLE NIGHTS WEDNESDAY NIGHT THROUGH FRIDAY NIGHT. && .AVIATION /00Z SUNDAY THROUGH THURSDAY/... EXPECT MORE IN THE WAY OF SHOWERS LATER TONIGHT...ALONG WITH MORE IN THE WAY OF LOW CIGS AND FOG. HOWEVER...STILL NOT SEEING OR EXPECTING A LARGE AMT OF ADVERSE WEATHER. EXPECT CONDITIONS TO IMPROVE BY LATE SUNDAY MORNING...AS WINDS SHIFT MORE TO THE WEST. WINDS MAY BE GUSTY AS INTENSE JULY SUN WARMS THINGS UP. BEST CHC FOR A GUSTY THUNDERSTORM WILL BE ALONG THE LEE SIDE TROUGH. OUTLOOK... MON...MAINLY VFR BUT WITH ISOLATED SHOWERS/STORMS PSBL. TUE...VFR/NO SIG WX. WED...SCT TSTM IMPACTS PSBL. THU...ISOLATED SHWR PSBL ACROSS S PA EARLY... OTHERWISE VFR. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LA CORTE NEAR TERM...GRUMM/LA CORTE/MARTIN SHORT TERM...GRUMM/LA CORTE LONG TERM...LAMBERT/GARTNER AVIATION...LA CORTE/MARTIN
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
916 PM CDT SAT JUL 14 2012 .UPDATE... MINOR SHORT TERM UPDATES BASED MOSTLY ON OBSERVED CONDITIONS. SEE BELOW FOR RATIONALE. && .DISCUSSION... SHOWERS AND THUNDERSTORMS HAVE DIMINISHED QUICKLY YET AGAIN THIS EVENING. UPDATED GRIDS FOR OBSERVED CONDITIONS IN THE VERY SHORT RANGE. LOW LEVEL CIRCULATION APPARENT IN RAP13...PROFILER WINDS...VWP WINDS AND SATELLITE LOOPS NEAR LONGVIEW (KGGG). AT 700MB PROFILER AND VWP WINDS SUGGEST TROUGH IS NEAR OR JUST OFF THE SE TEXAS COAST AND CURVE BACK TO THE LOW. PWAT VALUES DO APPEAR SLIGHTLY REDUCED FROM PREVIOUS EVENINGS WITH 00Z RAOB VALUES RANGING FROM 1.8 TO NEAR 2 INCHES. BLENDED TPW IMAGERY FOR THE CWA ARE AROUND 1.88 INCH SO STILL PLENTY MOISTURE RICH BUT A TAD LOWER. SFC MESO BOUNDARIES GALORE THIS EVENING FROM CONVECTIVE OUTFLOWS AND A LATE DEVELOPING SEA BREEZE. ONE BOUNDARY FROM NORTH OF COLLEGE STATION TO CALDWELL ON SOUTHWESTWARD. ANOTHER OVER COLORADO COUNTY..SEVERAL FROM CONVECTION OCCURRING NORTH OF CWA AND OLD SEA BREEZE BOUNDARY FROM LIBERTY TO KHOU TO KBYY. HRRR AND TX TECH WRF REFLECTIVITY FORECASTS ARE FOR GENERALLY QUIET NIGHT WITH SOME DEVELOPMENT TOWARDS SUNRISE BUT FEEL WITH MULTITUDE OF BOUNDARIES AND SLOWLY RETREATING TROUGH/LOW SOME ISOLATED TO SCATTERED CONVECTION POSSIBLE A COUPLE OF HOURS PRIOR TO SUNRISE MAINLY NEAR COAST AND NORTH OF A LINE FROM NORMANGEE TO LIVINGSTON NEARER TO 850-700MB LOW. THIS IS HANDLED WELL IN OUR CURRENT FORECAST LATER TONIGHT AND TOMORROW MORNING SO NO CHANGE NECESSARY. STILL A POSSIBILITY FOR SOME ISOLATED HEAVY RAINS ON SUNDAY SO MENTION OF LOCALLY HEAVY RAINS IN ZFP/GRIDS REMAINS A GOOD IDEA. 04 && .PREV DISCUSSION... /ISSUED 636 PM CDT SAT JUL 14 2012/ AVIATION... SCT LATE AFTN OUTFLOW DOMINATED SHRA/TSTMS SHOULD DIMINISH IN AREAL COVERAGE WITH THE LOSS OF HEATING. DO EXPECT SOME REDEVELOPMENT LATER TONIGHT AND TOWARD MORNING. THOUGH IT COULD BE ANYWHERE...MOST FAVORABLE LOCATIONS WOULD BE CLOSER TO THE COAST AND UP TOWARD THE LAKE LIVINGSTON AREA CLOSER TO THE UPPER CIRCULATION AND WHERE THE MORE FAVORABLE JET STRUCTURE WILL BE. BEST COURSE OF ACTION WILL PROBABLY BE TO USE VCSH/VCTS`S AND AMEND WHEN NECESSARY VERSUS CLUTTER TAFS WITH TEMPOS ETC. PRECIP SHOULD EXPAND IN COVERAGE WITH MID/LATE MORNING HEATING AGAIN SUNDAY. 47 && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 73 88 73 92 74 / 20 50 20 30 20 HOUSTON (IAH) 74 89 74 91 75 / 20 50 30 40 20 GALVESTON (GLS) 80 88 82 90 81 / 30 50 40 40 30 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ DISCUSSION...04
AREA FORECAST DISCUSSION
NWS SPOKANE WA
305 PM PDT Fri Jul 13 2012 .SYNOPSIS... Warm and increasingly humid conditions are expected over the Inland Northwest through the weekend as a slow-moving upper level low tracks through the region. this air mass will contribute to a chance of thunderstorms on both Saturday and Sunday. Some of the storms could produce locally heavy rains and possibly some large hail. the low will track out of the region late Sunday night or Monday followed by Seasonably with slight chances for thunderstorms. && .DISCUSSION... Tonight: Upper level low pressure system is spinning along coastal WA this afternoon. This is bring up monsoonal moisture from the Desert Southwest. This moisture is expected to push into our southeastern zones tonight. However, the more immediate threat will be surface based convection that is expected to develop during the late afternoon hours. First we need to break through the cap to release what is potentially a considerable amount of convective potential energy (CAPE). The strongest CAPE values of up to 2000 J/KG is located across the northern mountains with around 20-40 J/KG of convective inhibition (CIN) that has capped the atmosphere. South of a line from southern Kootenai County to Moses Lake will be significantly more CIN that will likely not get broken through the evening hours. The HRRR model shows Some convection begin to develop during the afternoon or early evening hours along and north of a line from Coeur d`Alene, Wilbur and to Moses Lake. This convection will move northward with potential risks including hail (potentially some sever in size), gusty outflow winds and cloud to ground lightning strikes. During the overnight hours, the monsoonal moisture moving northward will being to spread across our southeastern zones. Upper level laps rates will become increasingly more unstable through the night into tomorrow morning north and westward. Water vapor satellite imagery shows an upper level wave at the base of the low pressure system, currently across southwestern WA into western OR. This short wave will continue to rotate around the low in a counter-clockwise fashion where it is expected to swing around into southeast WA by the early morning hours tomorrow morning. This short wave will provide the lift that will kick off more widespread thunderstorm activity. /SVH Saturday...the closed upper low currently over NW WA will remain fixed over the region at least through Saturday afternoon. Models are in very good agreement that the low will dip slowly SE during the next 24 hrs...centering itself near The Dalles. As the low moves toward this area...it will begin to pool of monsoonal moisture currently over southern Idaho northward into much of our forecast area. This will result in increasing chances of precipitation through the day especially for locations north and east of the center of the low. Model guidance has been fairly wishy-washy on where to place the heaviest rain...but it should be co-located where we expected the greatest upper level difluence...NE WA/N ID and near the core of the low near the Cascades. Model stability parameters would place the greatest risk of thunderstorms along a theta-e ridge axis wrapping around the top of the low...or from the central ID Panhandle through the northern tier of WA and into the Cascades. We cannot entirely rule out severe thunderstorms based on CAPE values ranging from 1000-2000 j/kg with much weaker CIN or convective caps than what we are seeing today...however shear values away from the low are very weak. By Sunday...the low is only expected to move into the Blue Mts before opening up into a trough during the afternoon. This will result in likely showers and thunderstorms across the eastern third of WA and all of N Idaho through early afternoon. Then yet another strong upper level low tracks into the nw WA by late in the day. This low will likely destabilize the Cascades and result in another round of thunderstorms for much of the area. Heavy rains will again be possible. By Monday the second low is expected to meander slowly s-sw...through SW WA/NW OR which should lessen the chance for widespread convection for locations north of i90 and keep the risk of thunder going elsewhere. Temperatures forecasts over the next several days will prove a difficult task as much will depend on how widespread the convection becomes and what areas are impacted. Locations which see full sunshine will continue to see daytime readings in the 90s...while locations which see little if any sun could conceivably see highs in the mid 70s to lower 80s. fx Monday Night through Friday: No significant changes were made to the extended range part of the fcst, which keeps the upper low nearly stationary over the Pacific Nw through Wed. The recent trend in model guidance has the ECMWF becoming increasingly more aligned with the GFS the last couple runs. However...the ECMWF was the quickest with ejecting this stalled upper low NE across the region than the GFS by mid weak. Now it`s the GFS that has the faster ejection of the low, pushing its core NE through Oregon and Wa Wed and Wed Nt. A nearly non-existent upper trough on the ECMWF will dig south down the BC coast Wed Nt. These two models are nearly 180 degrees out of phase with this digging 500 mb low at this point...with the GFS much stronger, and certainly a more effective kicker/ejector of the stalled low. That said, we continued with a very conservative approach to making any big changes in the fcst based on the high level of uncertainty caused by the above mentioned differences. So, we did not go with a wet fcst for Wed Nt per the GFS. Leaning heavily toward a pattern recognition approach, we kept at least isolated rain showers and thunderstorms in nearly every period of the fcst. bz && .AVIATION... 18Z TAFS: Upper level low pressure system spinning over southwestern WA will continue to bring the risk for thunderstorms through Saturday afternoon. A wave rotating around the low into the Cascades will continue to generate a line of elevated thunderstorms into the early afternoon hours. There is a lot of uncertainty as far as where and how much surface based convection we will see later this afternoon. Models continue to show strong uncapped instability across the Cascades over into the Okanogan Highlands, as well as over into the Northern Panhandle. This is where we expect the best chances for afternoon thunderstorms to develop with the potential for a few strong storms. KEAT and more so KMWH will be on the southern fringe of this convection and may see a thunderstorm or two this afternoon before this activity lifts northward this evening. By tonight, we will shift to an elevated threat of thunderstorms around 03Z around the KLWS and KPUW taf sites then continuing to shift northward and westward into KGEG, KSFF, KCOE and possibly KMWH by the lat nighttime hours. /SVH && .PRELIMINARY POINT TEMPS/POPS... Spokane 68 87 65 81 60 84 / 30 40 50 70 50 20 Coeur d`Alene 66 86 62 76 58 84 / 50 50 60 70 50 20 Pullman 64 86 61 82 58 83 / 50 40 50 70 30 20 Lewiston 71 94 70 91 66 92 / 50 30 50 70 20 10 Colville 64 89 62 79 60 87 / 50 60 50 70 60 30 Sandpoint 63 82 58 76 55 82 / 60 70 50 70 50 30 Kellogg 64 83 60 76 56 84 / 90 70 60 80 50 30 Moses Lake 67 93 66 92 62 89 / 20 40 30 30 20 20 Wenatchee 69 93 70 89 65 88 / 30 30 30 30 20 20 Omak 67 95 66 87 63 89 / 50 60 30 50 50 40 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...None. WA...Red Flag Warning until 5 PM PDT Sunday for East Washington Central Cascade Valleys (Zone 677)-East Washington Northern Columbia Basin (Zone 673)-East Washington Okanogan/Methow Valleys (Zone 684)-East Washington South Central Cascade Valleys (Zone 676). && $$
AREA FORECAST DISCUSSION
NWS SPOKANE WA
1257 PM PDT Fri Jul 13 2012 .SYNOPSIS... Warm and increasingly humid conditions are expected over the Inland Northwest today and tomorrow. Showers and thunderstorms will bring the potential for locally heavy rain. Some spots could receive torrential rains on Saturday afternoon and Saturday evening under slow moving thunderstorms. The slow moving storm system responsible for the humid and stormy conditions will move out of the region by Sunday night. Seasonably warm conditions are expected next week with slight chances for thunderstorms. && .DISCUSSION... A quick update to the forecast for this afternoon. A tightly wound short wave rotating around the upper level low pressure system has shifted the elevated thunderstorm threat into the east slopes of the northern Cascades. Our attention is now focusing on the potential for surface based convection. Models continue to show uncapped energy to be tapped into from the northern portion of the Moses Lake Area, rotating clockwise around the northern portions of the Spokane Area and into the Central Panhandle Mountains. Visible satellite imagery does not show any cumulus development through 1245 PM, which indicates at least a weak cap that still needs to be overcome. The HRRR model suggests that we will see this cap get broken around 400 PM with thunderstorms developing across the Moses Lake Area, Waterville Plateau and Spokane Area. Oddly enough, this model does not develop any convection over the mountains initially. This is contrary to what is expected, thus I do not have a lot of confidence in the placement of the initial convection. We are going with convection to develop over the higher terrain later this afternoon with some isolated cells possible over the northern portion of the basin. LAPS data shows CAPE values of up to 2000 J/KG with a convective inhibition of around 20-50 J/KG across the northern mountains. Once this cap gets broken, I expect isolated to scattered thunderstorms to develop. Shear between 0-6 km is not strong, but will be enough to support supercells with the large amount of energy that is available to be tapped into. Any thunderstorms that develop will be capable of producing at least penny size hail stones with some isolated severe hail possible as well. /SVH && .AVIATION... 18Z TAFS: Upper level low pressure system spinning over southwestern WA will continue to bring the risk for thunderstorms through Saturday afternoon. A wave rotating around the low into the Cascades will continue to generate a line of elevated thunderstorms into the early afternoon hours. There is a lot of uncertainty as far as where and how much surface based convection we will see later this afternoon. Models continue to show strong uncapped instability across the Cascades over into the Okanogan Highlands, as well as over into the Northern Panhandle. This is where we expect the best chances for afternoon thunderstorms to develop with the potential for a few strong storms. KEAT and more so KMWH will be on the southern fringe of this convection and may see a thunderstorm or two this afternoon before this activity lifts northward this evening. By tonight, we will shift to an elevated threat of thunderstorms around 03Z around the KLWS and KPUW taf sites then continuing to shift northward and westward into KGEG, KSFF, KCOE and possibly KMWH by the lat nighttime hours. /SVH && .PRELIMINARY POINT TEMPS/POPS... Spokane 92 68 84 65 81 60 / 20 90 60 50 50 20 Coeur d`Alene 91 66 84 62 78 58 / 30 90 70 50 60 30 Pullman 87 64 84 61 83 58 / 10 80 50 60 50 20 Lewiston 95 71 89 70 89 66 / 10 50 50 60 50 20 Colville 96 64 85 62 79 60 / 50 90 70 50 60 50 Sandpoint 91 63 81 58 76 55 / 50 80 70 60 70 50 Kellogg 93 63 82 60 76 56 / 40 90 70 70 70 40 Moses Lake 95 68 91 66 92 62 / 20 40 30 30 20 20 Wenatchee 93 69 87 70 89 65 / 30 30 40 30 10 20 Omak 96 67 89 66 88 63 / 50 90 60 30 40 40 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...None. WA...None. && $$
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
637 PM CDT SAT JUL 14 2012 UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE .SHORT TERM...TONIGHT AND SUNDAY. LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW WEAK SHORTWAVE TROUGHING EXTENDING FROM LAKE SUPERIOR TO THE SOUTHERN MISSISSIPPI VALLEY EARLY THIS AFTERNOON. SCATTERED TO NUMEROUS SHOWER ACTIVITY DEVELOPED MIDDAY OVER NORTH-CENTRAL AND FAR NORTHEAST WISCONSIN THOUGH ACTIVITY HAS BEEN MUCH SLOWER TO DEVELOP OVER THE FOX VALLEY AND CENTRAL WISCONSIN. THE MOST PROMINENT BAND OF BROKEN SHOWERS APPEARS TO BE ALONG A SURFACE TROUGH WHICH EXTENDS FROM ABOUT HOUGHTON TO EAU CLAIRE. AS THE TROUGH EXITS THE AREA LATE THIS EVENING...PRECIP CHANCES ARE THE MAIN FORECAST CONCERN TONIGHT FOLLOWED BY TEMPS TOMORROW. TONIGHT...THE SHORTWAVE TROUGH WILL MOVE ACROSS EASTERN WISCONSIN DURING THE EVENING HOURS. FEEL THAT MUCH OF THE SHOWER AND THUNDERSTORM ACTIVITY WILL DIMINISH FAIRLY QUICKLY WITH LOSS OF DAYTIME HEATING...BUT CONVERGENCE UP TO 700 MB DOES LINGER OVER THE FAR EAST UNTIL 06Z SO WILL KEEP AN ISOLATED SHOWER MENTION THROUGH THAT TIME. PLENTY OF MOSTLY CLEAR SKIES UPSTREAM OVER MINNESOTA AND THINK THIS CLEARING WILL ARRIVE TONIGHT BEHIND THE TROUGH. THE BOUNDARY LAYER WILL REMAIN MOIST...ESPECIALLY IF GOOD RAINS DEVELOP THIS AFTERNOON...SO THINK THE COMBO OF LIGHT WINDS AND CLEAR SKIES WILL PROMOTE FOG FORMATION. WILL INCREASE WORDING TO AREAS OF FOG OVER THE HIGHER TERRAIN. LOWS MAINLY IN THE 60S WITH SOME 50S IN THE COLD SPOTS. SUNDAY...THE TROUGH WILL HAVE MOVED WELL TO EAST AT THE START OF SUNDAY...AND MID-LEVEL HEIGHTS WILL BE REBOUNDING THROUGH THE DAY. LIKE THE PREVIOUS FORECAST MENTIONED...WILL HAVE INSTABILITY DEVELOP THROUGH THE DAY WITH STEEP LOW LEVEL LAPSE RATES. BUT PLENTY OF DRY AIR WILL EXIST ABOVE THE MIXED LEVEL AND PROGGED SOUNDINGS INDICATE CAPPING WILL STRENGTHEN AS HEIGHTS REBOUND. DESPITE WEAK CONVERGENCE DEVELOPING OVER NE WISCONSIN ALONG THE LAKE BREEZE...THINK THE MIXING OF THE DRIER AIR ALOFT AND STRENGTHENING CAPPING WILL THWART SHOWER DEVELOPMENT. WILL STICK WITH A DRY FORECAST. 850MB TEMPS AROUND 20C ARGUES FOR LOW 90S FOR HIGHS...AND WILL GO WITH UPPER 80S NORTH TO MID 90S SOUTH. .LONG TERM...SUNDAY NIGHT THROUGH FRIDAY. OVERALL CURRENT TROF AND RIDGE PATTERN OVER THE U.S TO FLUCTUATE A BIT OVER AREA THROUGH THE PERIOD WITH MAIN WESTERLIES REMAINING OVER CENTRAL CANADA. MUCH OF THIS PERIOD WILL BE DEALING WITH RIDGE...ITS STRENGTH AND LOCATION AND ITS EFFECT ON TEMPERATURES. EXPECT CONTINUATION OF VERY WARM TO HOT CONDITIONS FOR MONDAY AND OVER THE SOUTH HALF ON TUESDAY BEFORE CANADIAN HIGH PRESSURE BRINGS SOME RELIEF TO ENTIRE AREA WEDNESDAY ONWARD. OVERALL MAX TEMPERATURES TO RUN AT OR ABOVE NORMS. ON MONDAY...INCREASING SOUTH TO SOUTHWEST FLOW AHEAD OF LOW PRESSURE OVER THE PLAINS TO CONTINUE HOT AND HUMID CONDITIONS WITH OVERNIGHT CONDITIONS SUN AND MON LEANING TOWARDS MUGGY SIDE. HEAT INDICES OVER FAR SOUTHERN CWA TO REACH 100 DURING THE AFTERNOON. LOW PRESSURE PASS TO OUR NORTH WILL PULL FRONT INTO LAKE SUPERIOR REGION. HAVE SLOWED PCPN MOVING INTO AREA KEEPING IT CLOSER TO OR BEHIND FRONT...MORE COLLATED WITH 850 BAROCLINIC ZONE. BEST POPS NORTH MON NIGHT CLOSER TO SUPPORTING JET DYNAMICS. ON TUESDAY...FRONT TO DROP SOUTH INTO SOUTHERN WI BY LATE AFTERNOON. FRONT WEAKENS AND HAVE LOSS OF JET SUPPORT...SO WILL STAY WITH LOWER POPS AS IT MOVES SOUTH. QUESTION THIS DAY IS MORE ON TEMPS WITH CLOUDS AND PCPN CAUSING ISSUES. FOR BOTH MONDAY AND TUESDAY...WESTERLY COMPONENT TO LLVL WINDS TO KEEP LAKE BREEZE RIGHT ALONG LAKE. SHEER IS LIMITED THROUGH THE PERIOD...SO DO NOT EXPECT ANY SIG SEVERE ATTM. HIGH PRESSURE DROPPING OUT OF CANADA WILL BRING A BIT LESS HEAT BUT ALSO DRIER AIRMASS INTO STATE...WITH DEW POINTS RETURNING INTO THE LOWER HALF OF THE 50S. DROPPED OVERNIGHT LOWS SLIGHTLY. && .AVIATION...AN UPPER LEVEL DISTURBANCE WILL MOVE ACROSS THE AREA THIS EVENING. IT WILL BE ACCOMPANIED BY SCATTERED SHOWERS AND THUNDERSTORMS THAT WILL COME TO AN END FROM NORTHWEST TO SOUTHEAST. SKIES WILL CLEAR OVERNIGHT WITH GROUND FOG POSSIBLE...ESPECIALLY AT PLACES LIKE LNL/ARV/EGV/RHI/TKV. SUNDAY WILL BE SUNNY AND HOT WITH LIGHT WINDS. RDM && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
304 PM CDT FRI JUL 13 2012 .SHORT TERM...TONIGHT AND SATURDAY. LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW VARIOUS SHORTWAVE TROUGHS EXTENDING FROM THE BOUNDARY WATERS OF MINNESOTA TO THE SOUTHERN MISSOURI VALLEY EARLY THIS AFTERNOON. AHEAD OF THESE TROUGHS...SHOWERS AND THUNDERSTORMS ARE MOST CLUSTERED OVER NORTHERN MINNESOTA AND ALSO OVER EASTERN IOWA AND NORTHERN MISSOURI. LOCAL MESOANALYSIS SHOWS CIN HAS ERODED OVER MUCH OF THE AREA WITH DAYTIME HEATING...AND WIDELY SCATTERED SHOWERS AND STORMS ARE NOW POPPING ACROSS MUCH OF THE FORECAST AREA. AS THE UPPER TROUGHS UPSTREAM SLOWLY MOVE EAST OVER THE NEXT 24 HOURS...PRECIP CHANCES ARE THE MAIN FORECAST CONCERN. TONIGHT...SHORTWAVE TROUGH OVER MINNESOTA AND OTHER WEAK IMPULSES ROTATING AROUND IT WILL SLOWLY MOVE SOUTHEAST ACROSS EASTERN MINNESOTA AND WESTERN WISCONSIN. LARGE-SCALE ASCENT IS PRETTY WEAK AND MID-LEVEL LAPSE RATES ARE ONLY AROUND 6 C/KM BUT THERE IS AMPLE MOISTURE AVAILABLE WITH PWATS AROUND AND SLIGHTLY HIGHER THAN 1.50 INCHES. AS A RESULT...THINK SPOTTY SHOWER ACTIVITY THAT POPPED UP THIS AFTERNOON WILL DIMINISH THIS EVENING. THEN AS THE SHORTWAVE ENERGY MOVES CLOSER...WILL SEE SCATTERED SHOWERS AND ISOLATED THUNDER PUSH BACK INTO THE WESTERN AND SOUTHERN PARTS OF THE FORECAST AREA. NOT ENTIRELY CONFIDENT IN COVERAGE SINCE SHOWERS AND STORMS WERE FAIRLY WIDESPREAD OVER WESTERN WISCONSIN WHEN I WALKED IN THE DOOR THIS MORNING. WILL PLAY THE ODDS OF THE DIURNAL CYCLE AND ERROR ON THE LOW SIDE. A MUGGY NIGHT WITH LOWS IN THE 60S. SATURDAY...THE SHORTWAVE TROUGH WILL MAKE SLOW PROGRESS EASTBOUND ACROSS THE STATE THROUGH THE DAY. THE 09Z SREF INDICATES THAT WILL SEE SHOWERS AND STORMS DEVELOP FAIRLY QUICKLY BETWEEN 15-18Z TOMORROW WHEN LOW LEVEL LAPSE RATES HAVE A CHANCE TO STEEPEN AND INSTABILITY TO DEVELOP. CAPES ARE NOT THAT IMPRESSIVE (600-700 J/KG) AND THEY ARE RATHER SKINNY...BUT THERE IS PLENTY OF MOISTURE AROUND (STILL 1.5 INCHES). WIND FIELDS ARE RATHER LIGHT SO STORMS SHOULD BE SLOW MOVING...BUT COVERAGE UPSTREAM ONLY SUGGESTS AN ISOLATED DAMAGING WIND AND HEAVY RAIN THREAT. THOUGH TEMPS WILL BE A FEW DEGREES COOLER...HIGHER HUMIDITY WILL MAKE IT FEEL MORE MUGGY. HIGHS RANGING THROUGH THE 80S. .LONG TERM...SATURDAY NIGHT THROUGH NEXT FRIDAY. AN UPPER LEVEL SHORT WAVE AND A SURFACE BOUNDARY WILL PASS EAST OF WISCONSIN DURING THE FIRST PERIOD OF THE FORECAST. ONLY HAVE CHANCE POPS GOING IN THE EAST AND THEN NOTHING AFTER 06Z SUNDAY...EXCEPT FOR SOME PATCHY FOG. A WARM FRONT PUSHING NORTH INTO WISCONSIN WILL BRING MUCH ABOVE NORMAL TEMPERATURES TO THE AREA...MAINLY ON MONDAY. THERE WILL BE A SLIGHT CHANCE OF SHOWERS AND STORMS IN THE NORTH ON MONDAY IN THE VICINITY OF THE FRONT. THERE IS A CHANCE OF THUNDERSTORMS MONDAY NIGHT AND TUESDAY ACROSS CENTRAL WISCONSIN AS A COLD FRONT MOVES THROUGH THE STATE. TEMPERATURES SHOULD REMAIN VERY WARM/HOT ON TUESDAY BUT THEY SHOULD BE A BIT COOLER THAN MONDAY WITH CLOUDS AND POSSIBLE CONVECTION. PRECIPITATION CHANCES MAINLY CONFINED TO CENTRAL AND EAST CENTRAL WISCONSIN ON TUESDAY NIGHT...THEN IT LOOKS LIKE A PERIOD OF DRY WEATHER WITH TEMPERATURES A LITTLE CLOSER TO NORMAL FOR THIS TIME OF YEAR. A SHORT WAVE MOVING SOUTHEAST ACROSS THE WESTERN GREAT LAKES REGION WILL BRING A CHANCE OF SHOWERS AND STORMS TO NORTHERN WISCONSIN ON FRIDAY. && .AVIATION...FOR 12Z TAF ISSUANCE. EXPECT CLD BASES TO RESULT IN MAINLY VFR CIGS. BUT SOME LOWER CIGS COULD DEVELOP IN RGNS OF MORE CONCENTRATED SHOWER ACTIVITY. IF ENOUGH RAIN FALLS TDA...SOME FG COULD DEVELOP TNGT...THOUGH BETTER CHC OF THAT WL BE SAT NGT. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ MPC/MG
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
242 PM CDT FRI JUL 13 2012 .SHORT TERM...TONIGHT THROUGH MONDAY NIGHT 242 PM CDT FRI JUL 13 2012 A RARE FORECAST CHALLENGE INVOLVING RAIN FOR THIS PACKAGE BUT DONT WORRY - HEAT STILL AN UPCOMING CONCERN AS WELL. WHILE UPPER RIDGE REMAINS OVER ROCKIES...AND IS PREDICTED TO BUILD BACK IN BY END OF WEEKEND...SHORT WAVE TROUGH APROACHING AREA FROM THE NORTHWEST. THIS HAD GENERATED SOME RAIN OVERNIGHT WITH LINGERING SHOWERS STILL TRANSVERSING THE AREA. MEANWHILE...KEEPING A CLOSE EYE ON NEW CONVECTIVE DEVELOPMENT IN REGION WITH DECENT DESTABILIZATION OVER MUCH OF CENTRAL AND SOUTHERN MINNESOTA THIS AFTERNOON WHERE EARLIER CLEARING HAD TAKEN PLACE. A BIT UNCLEAR ON HOW EXPANSIVE CONVECTION WILL BECOME HEADING INTO THE EVENING BUT WIND SHEAR IN ALL LAYERS REMAINS WEAK. MESOSCALE MODELS CONTINUE TO HINT AT MORE SCATTERED COVERAGE BUT HIGHLY VARIABLE IN THEIR OUTPUT. AIRMASS IS A BIT MORE STABLE OVER SOUTHEAST MINNESOTA COMPARED TO AREAS WHERE STRONGER STORMS ARE FORMING SO NOT SURE HOW INTENSE THEY COULD BE AS THEY ADVECT CLOSER. EITHER WAY NOT EXPECTING MUCH FOR ORGANIZATION WITH STORMS BUT LOCALIZED CORES COULD PRODUCE SMALL BOUTS OF HAIL AND GUSTY WINDS. RAINFALL WILL GENERALLY BE SPOTTY BUT HOPING MOST AREAS AT LEAST SEE SOME. MUCAPE VALUES WILL DROP OFF QUICKLY THIS EVENING SO CONVECTION TOO SHOULD WANE. TRENDED RAINFALL RISK IN THAT DIRECTION OVERNIGHT. 13.12Z MODEL SUITES IN GOOD AGREEMENT WITH SHORT WAVE TROUGH PASSAGE A BIT EARLIER THAN PREVIOUS FORECASTS...INTO GREAT LAKES BY SATURDAY AFTERNOON /15.00Z/. TRIED TO PUSH MAIN RAIN RISK ON SATURDAY MORE EAST OF THE RIVER THAN WEST WITH DIMINISHING CHANCES THROUGH THE DAY. AGAIN...RAINFALL LIKELY TO BE SPOTTY. HIGH PRESSURE BUILDS BACK IN FOR QUIET WEATHER SATURDAY NIGHT INTO SUNDAY. LOW LEVEL WARM AIR ADVECTION RETURNS IN EARNEST BY SUNDAY AFTERNOON THOUGH...ESPECIALLY NORTHWEST OF THE AREA. WILL SEE TEMPERATURES REBOUND AS UPPER RIDGE BEGINS TO BUILD BACK IN WITH HIGHS LIKELY IN THE 90S AND SOME HEAT INDEX VALUES APPROACHING 100. GUIDANCE 850 TEMPERATURES OF 22-25C SUGGESTED WITH ANOMOLIES OF +2 COULD SUPPORT AT LEAST NEAR RECORD HIGHS INTO MONDAY WITH SOME RETURNING MOISTURE AS WELL. DEPENDING ON HOW HEAT INDEX FORECAST DETAILS WORK OUT OVER THE WEEKEND...COULD SEE AT LEAST SHORT BOUT OF HEAT ADVISORIES FOR EARLY NEXT WEEK. .LONG TERM...TUESDAY THROUGH FRIDAY 242 PM CDT FRI JUL 13 2012 WHILE MEAN UPPER RIDGE ACROSS NATIONS MID SECTION CONTINUES TO BUILD IN OUTER FORECAST PERIODS...SUBTLE FEATURES IN LOWER LEVELS WILL BARE WATCHING. APPEARS THERE COULD BE ENOUGH NORTHWEST FLOW ALOFT TO PUSH FRONTAL BOUNDARY SOUTH ON TUESDAY. HIGHS TUESDAY WILL BE DEPENDENT ON THIS WITH ANOTHER HOT DAY AHEAD OF FRONT...ACROSS MAINLY SOUTH. GENERALLY GOING WITH IDEA THAT LARGE HUDSON BAY HIGH PRESSURE AREA WILL PUSH THIS BOUNDARY FAR ENOUGH SOUTH FOR DRY FORECAST AROUND MID WEEK UNTIL MORE WARMER AIR HEADS IN BY FRIDAY. && .AVIATION...THROUGH 18Z SATURDAY 1209 PM CDT FRI JUL 13 2012 SCATTERED SHOWERS AND THUNDERSTORMS CONTINUE TO BUBBLE ACROSS THE AREA THIS MORNING AHEAD OF THE SHORT WAVE TROUGH AND COLD FRONT CROSSING THE UPPER MIDWEST. JUST ENOUGH LIFT FROM THE SHORT WAVE TROUGH ALONG WITH BEING ON THE CONVERGENT EASTERN EDGE OF THE WEAK MOISTURE TRANSPORT IS PROVIDING JUST ENOUGH TO KEEP THE ACTIVITY GOING. THE 13.12Z RAP AND NAM SUGGEST LITTLE CHANGE IN THIS SET UP THROUGH THE AFTERNOON AS THE SHORT WAVE TROUGH AND COLD FRONT MOVE SLOWLY TO THE EAST SO EXPECTING THE SCATTERED ACTIVITY TO KEEP GOING/REDEVELOPING. CONFIDENCE ON WHEN THESE WILL BE NEAR THE TAF SITES REMAINS LOW SO WILL CONTINUE WITH VCTS AND UPDATED WHEN OR IF ANY ACTIVITY GETS CLOSE TO THE AIRPORTS. SHOULD SEE THE CONVECTION DIE OUT PRETTY QUICK THIS EVENING AS THE CAPE DIMINISHES. THE FRONT SHOULD MOVE THROUGH BOTH SITES SATURDAY MORNING WITH THE WINDS COMING AROUND TO THE WEST AND THEN NORTHWEST DURING THE AFTERNOON. && .ARX WATCHES/WARNINGS/ADVISORIES... 242 PM CDT FRI JUL 13 2012 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...SHEA LONG TERM....SHEA AVIATION.....04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1209 PM CDT FRI JUL 13 2012 .SHORT TERM...TODAY THROUGH SUNDAY NIGHT 245 AM CDT FRI JUL 13 2012 FORECAST CONCERNS FOCUS ON THE POTENTIAL FOR SHOWERS/STORMS OVER THE NEXT COUPLE DAYS. CURRENT CONVECTION ACROSS THE REGION FORMING AROUND A WEAK SFC BOUNDARY...SOME ELEVATED FRONTOGENESIS AND INSTABILITY...ALONG WITH A LOW LEVEL MOISTURE BOUNDARY. MESO MODELS NOT DOING A GREAT JOB WITH CAPTURING THE SHOWERS/STORMS. TRENDS THOUGH WOULD SUGGEST THAT THE ACTIVITY WILL GRADUALLY DIMINISH LATER THIS MORNING AS IT MOVES AWAY FROM THE MORE FAVORABLE ATMOSPHERE IN THE WEST. CONFIDENCE NOT OVERLY HIGH...BUT WILL TREND THE FORECAST WITH THIS IN MIND. CONDITIONS WILL BE MONITORED AND UPDATES TO THE FORECAST MADE...AS NEEDED. UPPER LEVEL SHORTWAVE TROUGH SET TO DRIVE SLOWLY EAST/SOUTHEAST FROM THE NORTHERN PLAINS EARLY THIS MORNING...TO ACROSS WI BY 18Z SAT. A SFC FRONT WILL ACCOMPANY THE SYSTEM...WITH SOME FRONTOGENETIC RESPONSE PORTRAYED BY THE NAM/GFS...ALTHOUGH NOT WELL DEFINED. MOISTURE TRANSPORT IS SOMEWHAT MEAGER AHEAD OF THE FRONT WITH SHALLOW WARM CLOUD DEPTHS...STILL ABOUT 1.5 PWS. NAM12 DOES BUILD ABOUT 2-3K J/KG OF MUCAPE AHEAD OF THE FRONT TODAY...AND ABOUT THE SAME FOR SAT. ITS A FAIRLY SKINNY CAPE PROFILE PER BUFKIT SOUNDINGS...USUALLY NOT SUPPORTIVE FOR EXPLOSIVE CONVECTION/STRONG UPDRAFTS. WIND SHEAR IS LOCATED WELL BEHIND THE SYSTEM THOUGH...AND DOES NOT LOOK TO BE MUCH OF FACTOR IN STORM DEVELOPMENT/ORGANIZATION. ALL IN ALL...THERE WILL BE ENOUGH ELEMENTS FOR MORE SHOWER/STORM DEVELOPMENT THIS AFTERNOON INTO SATURDAY. CAN/T RULE OUT A SEVERE RISK DESPITE THE POOR SETUP...MOSTLY WEST OF THE MISSISSIPPI RIVER. WHILE THIS SYSTEM SHOULD BRING SOME MUCH NEEDED RAIN TO PORTIONS OF THE FORECAST AREA...ITS NOT THE SOAKER THAT MOST NEED. .LONG TERM...MONDAY THROUGH THURSDAY 245 AM CDT FRI JUL 13 2012 DECENT AGREEMENT BETWEEN THE GFS AND ECMWF WITH TRACKING AN UPPER LEVEL SHORTWAVE TROUGH ACROSS SOUTHERN CANADA MON NIGHT-TUE...SLIDING AN ASSOCIATED SFC FRONT ACROSS THE UPPER MISSISSIPPI RIVER VALLEY. THERE LOOKS TO BE A FEED OF LOW LEVEL MOISTURE AHEAD OF THE BOUNDARY...WITH PWS OVER 1.5 INCHES AND SOME INSTABILITY ADDED TO THE MIX. SHOULD BE ENOUGH FOR SOME SHOWER/STORMS...BUT HOW WIDESPREAD THE ACTIVITY WOULD BE IS IN QUESTION. LATEST POSITIONING AND TIMING WOULD FAVOR THE BETTER CHANCES ACROSS THE SOUTH. A SFC HIGH THEN BUILDS BACK ACROSS THE REGION...WITH SOME SUGGESTION OF ANOTHER AMPLIFYING RIDGE FOR NEXT WEEKEND. AS FOR TEMPS...850 MB ANOMALIES CONTINUE TO PEG AROUND +2 FOR MON INTO TUE. MONDAY IS STILL SHAPING UP TO BE THE HOT DAY...WITH SOME LOCATIONS FLIRTING WITH 100 STILL POSSIBLE. THE FRONT WILL HAVE SOME SAY IN HIGHS FOR TUE...SO TIMING/POSITIONING WILL BE IMPORTANT. TEMPS SHOULD COOL BACK TO MORE SEASONABLE NORMALS...BUT HEAT COULD QUICKLY RETURN FOR NEXT WEEKEND IF THE AFOREMENTIONED RIDGE BUILDING OCCURS. && .AVIATION...THROUGH 18Z SATURDAY 1209 PM CDT FRI JUL 13 2012 SCATTERED SHOWERS AND THUNDERSTORMS CONTINUE TO BUBBLE ACROSS THE AREA THIS MORNING AHEAD OF THE SHORT WAVE TROUGH AND COLD FRONT CROSSING THE UPPER MIDWEST. JUST ENOUGH LIFT FROM THE SHORT WAVE TROUGH ALONG WITH BEING ON THE CONVERGENT EASTERN EDGE OF THE WEAK MOISTURE TRANSPORT IS PROVIDING JUST ENOUGH TO KEEP THE ACTIVITY GOING. THE 13.12Z RAP AND NAM SUGGEST LITTLE CHANGE IN THIS SET UP THROUGH THE AFTERNOON AS THE SHORT WAVE TROUGH AND COLD FRONT MOVE SLOWLY TO THE EAST SO EXPECTING THE SCATTERED ACTIVITY TO KEEP GOING/REDEVELOPING. CONFIDENCE ON WHEN THESE WILL BE NEAR THE TAF SITES REMAINS LOW SO WILL CONTINUE WITH VCTS AND UPDATED WHEN OR IF ANY ACTIVITY GETS CLOSE TO THE AIRPORTS. SHOULD SEE THE CONVECTION DIE OUT PRETTY QUICK THIS EVENING AS THE CAPE DIMINISHES. THE FRONT SHOULD MOVE THROUGH BOTH SITES SATURDAY MORNING WITH THE WINDS COMING AROUND TO THE WEST AND THEN NORTHWEST DURING THE AFTERNOON. && .ARX WATCHES/WARNINGS/ADVISORIES... 245 AM CDT FRI JUL 13 2012 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...RIECK LONG TERM....RIECK AVIATION...04
AREA FORECAST DISCUSSION...UPDATED
NWS RENO NV
905 PM PDT SAT JUL 14 2012 .UPDATE... CONVECTION FINALLY GOT ENOUGH INSTABILITY TO BREAK THROUGH THE CAP IN MINERAL COUNTY. WENT AHEAD AND PUT ISOLATED SHOWERS AND THUNDERSTORMS BACK INTO THE FORECAST FOR MINERAL COUNTY, AS WE COULD SEE A FEW STORMS MAINLY SOUTH AND EAST OF HAWTHORNE BEFORE MIDNIGHT. HOON && .PREVIOUS DISCUSSION... /ISSUED 454 PM PDT SAT JUL 14 2012/ UPDATE... WENT AHEAD AND PULLED THE THUNDERSTORM CHANCES FOR THE REMAINDER OF THIS AFTERNOON AND EVENING. CUMULUS BUILDUPS IN MONO- MINERAL JUST DON`T HAVE ENOUGH MOISTURE/INSTABILITY TO REALLY GET GOING TODAY. DRY AIRMASS HAS PUSHED THE BULK OF THE MOISTURE INTO EASTERN NEVADA. ALL PUBLIC AND FIRE PRODUCTS HAVE BEEN UPDATED AND SENT. WEB PRODUCTS WILL UPDATE SHORTLY. AS FOR TOMORROW`S FORECAST, WITH THE DRYING THAT WE SAW TODAY, TOMORROW IS LOOKING MUCH LESS PROBABLE FOR THUNDERSTORMS. POPS WILL LIKELY BE TRIMMED BACK FOR SUNDAY, BUT WILL WAIT UNTIL THE 00Z MODEL RUNS TO COME IN BEFORE MAKING ANY BIG CHANGES TO SUNDAY. HOON PREVIOUS DISCUSSION... /ISSUED 201 PM PDT SAT JUL 14 2012/ SHORT TERM... CURRENT WATER VAPOR IMAGERY DEPICTS A VERY DRY AIRMASS ALOFT THAT HAS MOVED ACROSS WESTERN NEVADA OVERNIGHT AND THIS MORNING. COMPARED TO YESTERDAY MORNING, THE 12Z OBSERVED PRECIPITABLE WATER AT KRNO DROPPED 0.20 INCHES (TO 0.37 IN). WITH THE DEEPER MOISTURE DISPLACED TO THE EAST, CONVECTION HAS BEEN A LOT SLOWER TO DEVELOP THIS AFTERNOON. BASED ON THE LATEST HRRR FORECAST, VISIBLE SATELLITE AND RADAR TRENDS, DECIDED TO TRIM BACK COVERAGE OF THUNDERSTORMS FOR THIS AFTERNOON AND EVENING. THE BEST CHANCE WILL BE ACROSS MINERAL, EASTERN MONO AND SOUTHEASTERN CHURCHILL COUNTIES WHERE THE LATEST SPC MESOANALYSIS SHOWS MUCAPES OF AROUND 500 J/KG. WITH LITTLE IN THE WAY OF SHEAR, ANY STORMS THAT FORM WILL BE PULSE STORMS THAT WILL SLOWLY DRIFT TO THE EAST-NORTHEAST. ON SUNDAY, THE 12Z GFS/NAM/ECMWF ARE IN GOOD AGREEMENT THAT THE AREA OF LOW PRESSURE OVER CENTRAL OREGON WILL LIFT TO THE NORTHEAST WHILE A WEAK AREA OF LOW PRESSURE DEVELOPS NEAR THE CENTRAL CALIFORNIA COAST. THIS WILL SET UP AN AREA OF DEFORMATION ACROSS THE RENO CWA FROM TAHOE NORTHEAST TO WINNEMUCCA. SOUTH OF THIS BOUNDARY, THE FLOW WILL TURN MORE SOUTHERLY, ALLOWING MONSOON MOISTURE TO BUILD BACK ACROSS SOUTHEASTERN HALF OF THE CWA WITH MODEL PWATS INCREASING TO NEAR 0.75 INCHES. THE EXISTING FORECAST LOOKS GOOD WITH ISOLATED COVERAGE SOUTH OF I-80 AND SCATTERED STORMS SOUTH OF US-50. THE STORMS ACROSS MINERAL AND MONO COUNTIES WILL BE ON THE WET SIDE, WITH WET/DRY HYBRID STORMS CLOSER TO THE MOISTURE BOUNDARY BETWEEN I-80 AND US-50 (SEE THE FIRE WEATHER DISCUSSION BELOW FOR MORE DETAILS). THE WEAKNESS NEAR THE CALIFORNIA COAST WILL WEAKEN ON MONDAY AS A STRONGER AREA OF LOW PRESSURE BUILDS SOUTH ACROSS WESTERN WASHINGTON AND OREGON. THIS WILL TURN THE UPPER LEVEL FLOW BACK TO THE SOUTHWEST, USHERING IN DRIER AIR ACROSS THE RENO CWA. THE BEST CHANCE FOR ANY CONVECTION WILL BE ACROSS MINERAL AND MONO COUNTIES, CLOSER TO THE DEEPER MOISTURE. THE AREA OF LOW PRESSURE WILL CONTINUE TO SLIDE SLOWLY SOUTH ACROSS WESTERN OREGON ON TUESDAY. THIS WILL KEEP DRY SOUTHWEST FLOW IN PLACE. DEPENDING ON THE PLACEMENT OF THE LOW, THERE IS A VERY SMALL CHANCE THAT EXTREME NORTHERN LASSEN COUNTY AND THE SURPRISE VALLEY COULD SEE A PASSING SHOWER ON TUESDAY AFTERNOON SO A SLGT CHANCE WAS INTRODUCED WITH THIS PACKAGE FOR THOSE AREAS. MYRICK LONG TERM...WEDNESDAY THROUGH SATURDAY... A TROUGH LOCATED OVER THE PACIFIC NORTHWEST WILL CREATE A DRY AND STABLE SOUTHWEST FLOW ALOFT WEDNESDAY AND THURSDAY. NUMERICAL GUIDANCE DIFFERS FOR FRIDAY AND SATURDAY...SOME SOLUTIONS BRING THE TROUGH EASTWARD WHILE OTHER SOLUTIONS MOVE IT WESTWARD AND BUILD THE RIDGE OVER THE EASTERN SIERRA AND WESTERN NEVADA. THE OVERALL CONSENSUS IS FOR A DRY FORECAST WITH A WARMING TREND THROUGH SATURDAY...WHICH IS ALREADY COVERED WELL BY THE ONGOING FORECAST. ONE WILD CARD IS THE SLIGHT CHANCE THAT MOISTURE FROM THE REMNANTS OF HURRICANE FABIO COULD BE DRAWN NORTHWARD FRIDAY. TWO RECENT RUNS OF THE GFS ARE THE ONLY ONES SHOWING THIS SOLUTION. WITH FABIO CURRENTLY LOCATED 550 MILES SSW OF THE SOUTHERN TIP OF BAJA-CALIFORNIA CONFIDENCE IS VERY LOW IN THIS SCENARIO. FOR NOW A SLIGHT CHANCE OF THUNDERSTORMS WAS INTRODUCED FRIDAY FOR MONO COUNTY. JCM AVIATION... VFR CONDITIONS WILL PREVAIL OVERALL THROUGH THE WEEKEND AND INTO NEXT WEEK. THUNDERSTORMS ARE POSSIBLE SUNDAY AFTERNOON FROM I-80 SOUTHWARD. IN THE VICINITY OF THESE STORMS THE CIG/VSBYS SHOULD BE AOA 5000/5 WITH GUSTY SFC WINDS. FOR THE TERMINALS ISOLATED STORMS ARE POSSIBLE SUNDAY AFTERNOON AND EARLY EVENING IN THE VICINITIES OF KTRK..KTVL AND KRNO...WITH SOMEWHAT BETTER POTENTIAL FOR THUNDERSTORMS IN THE VICINITY OF KMMH. JCM FIRE WEATHER... HAVE TRIMMED BACK THUNDERSTORM COVERAGE THIS AFTERNOON BASED ON LATEST RADAR AND SATELLITE TRENDS TO ENCOMPASS EASTERN MONO COUNTY INTO MINERAL AND EASTERN CHURCHILL COUNTIES. WITH PLENTY OF MID AND UPPER LEVEL DRY AIR WORKING INTO THE REGION IT HAS SUPPRESSED THUNDERSTORM DEVELOPMENT. TYPICAL AFTERNOON ZEPHYR WINDS CAN BE EXPECTED WITH GUSTS OF 25 TO 30 MPH LATE THIS AFTERNOON AND INTO THE EARLY EVENING. THESE GUSTS WILL CORRESPOND WITH HUMIDITY VALUES AROUND 10-15% WITH LOCALLY CRITICAL CONDITIONS POSSIBLE. HOWEVER, THESE WILL NOT BE WIDESPREAD ENOUGH TO WARRANT ANY RED FLAG WARNINGS TODAY. AFTERNOON WESTERLY WINDS CAN BE EXPECTED AGAIN SUNDAY, BUT WILL BE ABOUT 5 MPH LESS IN SPEED. A PIECE OF ENERGY AND WEAK DEFORMATION BAND WILL HELP TO FOCUS THUNDERSTORM DEVELOPMENT SUNDAY AFTERNOON WITH ISOLATED COVERAGE POSSIBLE BETWEEN INTERSTATE 80 AND HIGHWAY 50 AND SCATTERED COVERAGE SOUTH OF HIGHWAY 50. THE DEEPEST MOISTURE WILL BE SOUTH OF HIGHWAY 50 AND EAST OF HIGHWAY 95, SO STORMS THROUGH THIS AREA WILL BE WET. NORTH AND WEST OF THERE, A HYBRID OF STORMS ARE POSSIBLE WITH THE POTENTIAL FOR A DRY LIGHTNING STRIKE OUTSIDE OF THE WET THUNDERSTORM CORE. THIS COULD START NEW FIRES, BUT WITH THE SMALL AREA OF HYBRID STORMS, AM NOT PLANNING ANY RED FLAG WARNINGS AT THIS TIME. IN ADDITION, WATCHING HOW THE DRY AIR WORKING INTO CALIFORNIA AND WESTERN NEVADA HAS SQUELCHED THUNDERSTORM DEVELOPMENT TODAY, AM A BIT CONCERNED THAT MODELS MAY BE OVERDOING THE CONVECTIVE POTENTIAL SUNDAY AND COVERAGE MAY NEED TO BE TRIMMED A BIT. DF && .REV WATCHES/WARNINGS/ADVISORIES... NV...NONE. CA...NONE. && $$ FOR MORE INFORMATION FROM THE NATIONAL WEATHER SERVICE VISIT... HTTP://WEATHER.GOV/RENO (ALL LOWER CASE)
AREA FORECAST DISCUSSION...CORRECTED
NWS NEW YORK NY
519 AM EDT SUN JUL 15 2012 .SYNOPSIS... A WEAK COLD FRONT WILL APPROACH THE AREA TODAY AND MOVE ACROSS TONIGHT. HOT AND HUMID CONDITIONS WILL THEN PERSIST THROUGH THE MIDDLE OF THE WEEK WITH A BERMUDA HIGH PRESSURE SYSTEM DOMINATING OUR WEATHER. A STRONGER COLD FRONT WILL MOVE ACROSS THE REGION ON WEDNESDAY...FOLLOWED BY HIGH PRESSURE AND MORE SEASONABLE CONDITIONS FOR THE END OF THE WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... CLOUDS WILL INCREASE FROM W TO E THIS MORNING AS UPPER RIDGE AXIS SLIDES E. TRICKY FORECAST TODAY IN REGARDS TO POPS BUT THINKING THERE WILL BE TWO ROUNDS OF ACTIVITY. THE FIRST IS THIS MORNING WITH A WEAK SHORTWAVE. HAVE YET TO SEE SHOWERS BEGIN EXPANDING...BUT 00Z SPC WRF AND LATEST HRRR HIGH RES MODELS ARE IN GOOD AGREEMENT THAT SHOWERS SHOULD START BECOMING MORE NUMEROUS BETWEEN 09Z AND 12Z IN NJ AND PA AND TRACK INTO NE NJ. EASTERN SECTIONS PROBABLY WON`T SEE MUCH OF ANYTHING THIS MORNING AND MUCH OF THE DAY MAY EVEN BE DRY. MAY HAVE GONE OVERBOARD WITH POPS THIS MORNING AND MAY NEED TO DECREASE THEM. SOUNDINGS ARE INDICATING ELEVATED INSTABILITY IS PRESENT SO HAVE KEPT THE MENTION OF THUNDER. THERE IS UNCERTAINTY WITH HOW THE AFTERNOON PLAYS OUT. BOTH NAM AND GFS ARE INDICATING NVA OVER THE AREA WITH THE SECOND SHORTWAVE MOVING ACROSS TONIGHT. HOWEVER WEAK SFC TROUGH ACROSS WESTERN ZONES SHOULD BE ENOUGH TO TRIGGER SCT SHOWERS/TSTMS ACROSS WESTERN PORTIONS OF THE AREA. PWATS INCREASE TO 2+ INCHES THIS AFTERNOON WITH INCREASING THETA E AND TALL SKINNY CAPE PROFILES WHICH ARE FAVORABLE FOR HEAVY RAIN. NAM IS NOW KEEPING STRONGER SHEAR TO THE WEST...WHILE GFS INCREASES IT TO 25-30 KT THIS AFTN AND EVE. THEREFORE THERE IS A CHANCE THAT THE MID LEVEL FLOW COULD BE STRONG ENOUGH TO PRODUCE A FEW STRONG STORMS. HOWEVER...EXPECT THE MAIN THREAT TO BE URBAN AND SMALL STREAM FLOODING. SEE HYDRO SECTION BELOW FOR MORE DETAILS. HIGHS ARE EXPECTED TO RANGE BETWEEN MID AND UPPER 80S...BUT WILL ALSO DEPEND ON THICKNESS OF CLOUD COVER AND ANY PRECIP THIS MORNING. && .SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/... WEAK COLD FRONT AND UPPER SHORTWAVE MOVE ACROSS TONIGHT WITH DECREASING ATMOSPHERIC MOISTURE LEVELS AND THEREFORE DECREASING THE HEAVY RAIN THREAT. HIGHEST POPS ARE CONFINED TO THIS TIME PERIOD WHEN THERE WILL BE BETTER SYNOPTIC FORCING PRESENT. FRONT SHOULD BE S OF THE AREA BY 12Z. MUCH MORE SUN EXPECTED ON MON WITH RISING HEIGHTS AND H85 TEMPS AROUND 17-18C. THIS TRANSLATES TO HIGHS IN THE LOWER TO MID 90S...SLIGHTLY COOLER AT THE IMMEDIATE COAST. SW FLOW COURTESY OF BERMUDA HIGH OVER THE ATLANTIC WILL ALSO KEEP IT MUGGY WITH DEWPOINTS GENERALLY AROUND THE 70 DEGREE MARK. THIS WILL RESULT IN HEAT INDICES IN THE MID TO UPPER 90S FOR MUCH OF THE AREA. NYC WILL LIKELY NEED A HEAT ADVSY FOR MON...BUT ITS STILL A THIRD PERIOD EVENT SO WILL HOLD OFF. DESPITE A THERMAL TROUGH ACROSS THE AREA ON MONDAY...WARM MID LEVELS WILL KEEP A LID ON ANY SHOWER/TSTM ACTIVITY. && .LONG TERM /TUESDAY THROUGH SATURDAY/... A WARM RIDGE ALOFT WILL ENCAPSULATE MUCH OF THE COUNTRY EAST OF THE ROCKIES THROUGH THE MIDDLE OF NEXT WEEK...WHILE A POLAR VORTEX OVER HUDSON BAY IN CANADA DESCENDS SE AND CARVES OUT A STRONG UPPER TROF ACROSS EASTERN CANADA AND THE NORTHEAST MID TO LATE WEEK. THE LATTER OF WHICH WILL ALSO SEND A STRONG COLD FRONT THROUGH THE REGION ON WED AFT/EVE. PRIOR TO THAT TIME...HOT...MUGGY WEATHER WILL BE ON TAP FOR MON-WED. GLOBAL MODELS ARE IN GOOD AGREEMENT WITH THE MASS FIELDS AND KEEP THE AREA DRY MON AND TUE AHEAD OF THE MID WEEK COLD FRONT. MODEL UPPER AIR SOUNDINGS SHOW STRONG MID LEVEL CAPPING WITH A DRY MIXED LAYER. IT WILL BE HOT AND HUMID TUE-WED WITH HIGHS GENERALLY IN THE MID TO UPPER 90S FOR TUE. EXPECT COOLER CONDITIONS ALONG THE IMMEDIATE COAST. OVERNIGHT LOWS WILL MAINLY BE IN THE 70S. THE TRICKY PART OF THE FORECAST COMES WITH HEAT INDEX VALUES....WITH MID 90S TO AROUND 100 FOR TUE AND WED. MODELS...IN PARTICULAR...THE GFS AND NAM...DIFFER IN HOW MUCH MIXING THERE IS IN THE BOUNDARY LAYER. THIS TYPICALLY RESULTS IN DEW POINTS SEVERAL DEGREES COOLER IN THE NAM...WITH THE GFS NOTORIOUSLY HIGHER AND POOR AT MIXING DRIER AIR TO THE SURFACE. A COMPROMISE OF THE GUIDANCE WAS USED HERE. HEAT ADVISORIES WILL LIKELY BE REQUIRED FOR PORTIONS OF THE AREA...IN PARTICULAR NYC METRO. A STRONG COLD FRONT IMPACTS THE AREA WED AFT/EVE WITH ANOTHER GOOD CHANCE FOR CONVECTION. MODERATE TO HIGH INSTABILITY AND WEAK SHEAR WILL LIKELY PRODUCE ISOLATED STRONG TO SEVERE CONVECTION. DRIER...MORE SEASONABLE CONDITIONS RETURN FOR THU-SAT AS STRONG CANADIAN HIGH PRESSURE BUILDS SE FROM THE GREAT LAKES. && .AVIATION /08Z SUNDAY THROUGH THURSDAY/... WEAK HIGH PRESSURE AND A WEAK TROUGH OF LOW PRESSURE REMAIN IN THE VICINITY TODAY. A WEAK COLD FRONT PASSES THROUGH TONIGHT. SHOULD BE VFR MOST OF THE DAY...BUT CIGS 2000-3000 FT POSSIBLE WITH MORNING SHOWERS. THESE SHOWERS HAVE NOT YET FORMED...BUT SCATTERED COVERAGE IS ANTICIPATED TO DEVELOP AND BE IN THE VICINITY BY AROUND 12Z. NOT ENOUGH CONFIDENCE TO GO WITH TSTMS IN THE MORNING. ANOTHER ROUND OF SHOWERS WITH A BETTER CHANCE OF EMBEDDED TSTMS IS ANTICIPATED LATE THIS AFTERNOON INTO THE EVENING AHEAD OF AN APPROACHING WEAK COLD FRONT. LOCAL MVFR TO IFR CONDITIONS POSSIBLE DURING THIS TIME. SHOWERS/TSTMS STILL POSSIBLE AT ANY POINT THIS AFTERNOON...HOWEVER...NOT ENOUGH CONFIDENCE IN GOING WITH A PREVAILING MENTION OF EITHER BEFORE THE TIMING OF THE PROB30 GROUPS. OUTLOOK FOR 06Z MON THROUGH THU... .SUN NIGHT...CONTINUED CHANCE OF MVFR/IFR CONDITIONS IN ANY SHOWERS/TSTMS. .MON-TUE...VFR. .WED...SCT AFTERNOON SHOWERS/TSTMS. .THU...VFR. && .MARINE... MAINLY SW TO WSW FLOW 10-15 KT ACROSS THE OPEN OCEAN WATERS...AND 5-10 KT ELSEWHERE THROUGH WEDNESDAY. OCCASIONAL GUSTS JUST BELOW 25 KT ARE POSSIBLE IN THE NY BIGHT REGION AND NEAR SHORE THIS AFTERNOON INTO THIS EVENING. WAVEWATCH SEAS APPEAR A LITTLE OVERDONE LATE THIS AFTERNOON INTO TONIGHT. AS A RESULT HAVE CAPPED OCEAN SEAS AT 4 FT THROUGH TONIGHT. SEAS THEREAFTER PRIMARILY 2 TO 4 FT. THUNDERSTORMS WILL BE POSSIBLE MAINLY LATE THIS AFTERNOON AND TONIGHT...AND ONCE AGAIN WEDNESDAY AFTERNOON AND NIGHT AS A COLD FRONT APPROACHES AND PASSES THROUGH. WINDS SHIFT NORTHERLY BEHIND THE FRONT ON THURSDAY WITH PERHAPS A WEAK ONSHORE FLOW DEVELOPING LOCALLY DURING THE AFTERNOON. && .HYDROLOGY... WHILE BASIN AVG QPF THROUGH TONIGHT RUNS FROM AROUND 1/3 TO 3/4 INCH...HIGHEST NW OF NYC AND LOWEST OVER ERN CT/LONG ISLAND...LOCALLY HEAVY RAINFALL OF 1-2 INCHES OR MORE IS POSSIBLE UNDER ANY STRONGER CONVECTION GIVEN THE FORECAST NEAR- TROPICAL NATURE OF THE ATMOSPHERE...AS CONVECTION WILL BE VERY EFFICIENT IN CONVERTING AVAILABLE MOISTURE TO RAINFALL. THERE IS FAIRLY HIGH POTENTIAL FOR MINOR URBAN/POOR DRAINAGE/SMALL STREAM FLOODING. LOCALIZED FLASH FLOODING CANNOT BE RULED OUT...ESPECIALLY IN AREAS THAT EXPERIENCE MULTIPLE ROUNDS OF HEAVY RAIN...BUT THE FLASH FLOOD THREAT PROBABILITY/COVERAGE BOTH APPEAR TOO SMALL TO WARRANT A FLASH FLOOD WATCH. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...NONE. && $$
AREA FORECAST DISCUSSION
NWS NEW YORK NY
443 AM EDT SUN JUL 15 2012 .SYNOPSIS... A WEAK COLD FRONT WILL APPROACH THE AREA TODAY AND MOVE ACROSS TONIGHT. HOT AND HUMID CONDITIONS WILL THEN PERSIST THROUGH THE MIDDLE OF THE WEEK WITH A BERMUDA HIGH PRESSURE SYSTEM DOMINATING OUR WEATHER. A STRONGER COLD FRONT WILL MOVE ACROSS THE REGION ON WEDNESDAY...FOLLOWED BY HIGH PRESSURE AND MORE SEASONABLE CONDITIONS FOR THE END OF THE WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... TRICKY FORECAST TODAY IN REGARDS TO POPS BUT THINKING THERE WILL BE TWO ROUNDS OF ACTIVITY. THE FIRST IS THIS MORNING WITH A WEAK SHORTWAVE. HAVE YET TO SEE SHOWERS BEGIN EXPANDING...BUT 00Z SPC WRF AND LATEST HRRR HIGH RES MODELS ARE IN GOOD AGREEMENT THAT SHOWERS SHOULD START BECOMING MORE NUMEROUS BETWEEN 09Z AND 12Z IN NJ AND PA AND TRACK INTO NE NJ. EASTERN SECTIONS PROBABLY WON`T SEE MUCH OF ANYTHING THIS MORNING AND MUCH OF THE DAY MAY EVEN BE DRY. MAY HAVE GONE OVERBOARD WITH POPS THIS MORNING AND MAY NEED TO DECREASE THEM. SOUNDINGS ARE INDICATING ELEVATED INSTABILITY IS PRESENT SO HAVE KEPT THE MENTION OF THUNDER. THERE IS UNCERTAINTY WITH HOW THE AFTERNOON PLAYS OUT. BOTH NAM AND GFS ARE INDICATING NVA OVER THE AREA WITH THE SECOND SHORTWAVE MOVING ACROSS TONIGHT. HOWEVER WEAK SFC TROUGH ACROSS WESTERN ZONES SHOULD BE ENOUGH TO TRIGGER SCT SHOWERS/TSTMS ACROSS WESTERN PORTIONS OF THE AREA. PWATS INCREASE TO 2+ INCHES THIS AFTERNOON WITH INCREASING THETA E AND TALL SKINNY CAPE PROFILES WHICH ARE FAVORABLE FOR HEAVY RAIN. THEREFORE...EXPECT THE MAIN THREAT TO BE URBAN AND SMALL STREAM FLOODING. SEE HYDRO SECTION BELOW FOR MORE DETAILS. NAM IS NOW KEEPING STRONGER SHEAR TO THE WEST...WHILE GFS INCREASES IT TO 25-30 KT THIS AFTN AND EVE. THEREFORE IS A CHANCE THAT THE MID LEVEL FLOW COULD BE STRONG ENOUGH TO PRODUCE A FEW STRONG STORMS. CLOUDS WILL INCREASE FROM W TO E THIS MORNING AS UPPER RIDGE AXIS SLIDES E. HIGHS ARE EXPECTED TO RANGE BETWEEN MID AND UPPER 80S...BUT WILL ALSO DEPEND ON THICKNESS OF CLOUD COVER AND ANY PRECIP THIS MORNING. && .SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/... WEAK COLD FRONT AND UPPER SHORTWAVE MOVE ACROSS TONIGHT WITH DECREASING ATMOSPHERIC MOISTURE LEVELS AND THEREFORE DECREASING THE HEAVY RAIN THREAT. HIGHEST POPS ARE CONFINED TO THIS TIME PERIOD WHEN THERE WILL BE BETTER SYNOTIC FORCING PRESENT. FRONT SHOULD BE S OF THE AREA BY 12Z. MUCH MORE SUN EXPECTED ON MON WITH RISING HEIGHTS AND H85 TEMPS AROUND 17-18C. THIS TRANSLATES TO HIGHS IN THE LOWER TO MID 90S...SLIGHTLY COOLER AT THE IMMEDIATE COAST. SW FLOW COURTESY OF BERMUDA HIGH OVER THE ATLANTIC WILL ALSO KEEP IT MUGGY WITH DEWPOINTS GENERALLY AROUND THE 70 DEGREE MARK. THIS WILL RESULT IN HEAT INDICES IN THE MID TO UPPER 90S FOR MUCH OF THE AREA. NYC WILL LIKELY NEED A HEAT ADVSY FOR MON...BUT ITS STILL A THIRD PERIOD EVENT SO WILL HOLD OFF. && .LONG TERM /TUESDAY THROUGH SATURDAY/... A WARM RIDGE ALOFT WILL ENCAPSULATE MUCH OF THE COUNTRY EAST OF THE ROCKIES THROUGH THE MIDDLE OF NEXT WEEK...WHILE A POLAR VORTEX OVER HUDSON BAY IN CANADA DESCENDS SE AND CARVES OUT A STRONG UPPER TROF ACROSS EASTERN CANADA AND THE NORTHEAST MID TO LATE WEEK. THE LATTER OF WHICH WILL ALSO SEND A STRONG COLD FRONT THROUGH THE REGION ON WED AFT/EVE. PRIOR TO THAT TIME...HOT...MUGGY WEATHER WILL BE ON TAP FOR MON-WED. GLOBAL MODELS ARE IN GOOD AGREEMENT WITH THE MASS FIELDS AND KEEP THE AREA DRY MON AND TUE AHEAD OF THE MID WEEK COLD FRONT. MODEL UPPER AIR SOUNDINGS SHOW STRONG MID LEVEL CAPPING WITH A DRY MIXED LAYER. IT WILL BE HOT AND HUMID TUE-WED WITH HIGHS GENERALLY IN THE MID TO UPPER 90S FOR TUE. EXPECT COOLER CONDITIONS ALONG THE IMMEDIATE COAST. OVERNIGHT LOWS WILL MAINLY BE IN THE 70S. THE TRICKY PART OF THE FORECAST COMES WITH HEAT INDEX VALUES....WITH MID 90S TO AROUND 100 FOR TUE AND WED. MODELS...IN PARTICULAR...THE GFS AND NAM...DIFFER IN HOW MUCH MIXING THERE IS IN THE BOUNDARY LAYER. THIS TYPICALLY RESULTS IN DEW POINTS SEVERAL DEGREES COOLER IN THE NAM...WITH THE GFS NOTORIOUSLY HIGHER AND POOR AT MIXING DRIER AIR TO THE SURFACE. A COMPROMISE OF THE GUIDANCE WAS USED HERE. HEAT ADVISORIES WILL LIKELY BE REQUIRED FOR PORTIONS OF THE AREA...IN PARTICULAR NYC METRO. A STRONG COLD FRONT IMPACTS THE AREA WED AFT/EVE WITH ANOTHER GOOD CHANCE FOR CONVECTION. MODERATE TO HIGH INSTABILITY AND WEAK SHEAR WILL LIKELY PRODUCE ISOLATED STRONG TO SEVERE CONVECTION. DRIER...MORE SEASONABLE CONDITIONS RETURN FOR THU-SAT AS STRONG CANADIAN HIGH PRESSURE BUILDS SE FROM THE GREAT LAKES. && .AVIATION /08Z SUNDAY THROUGH THURSDAY/... WEAK HIGH PRESSURE AND A WEAK TROUGH OF LOW PRESSURE REMAIN IN THE VICINITY TODAY. A WEAK COLD FRONT PASSES THROUGH TONIGHT. SHOULD BE VFR MOST OF THE DAY...BUT CIGS 2000-3000 FT POSSIBLE WITH MORNING SHOWERS. THESE SHOWERS HAVE NOT YET FORMED...BUT SCATTERED COVERAGE IS ANTICIPATED TO DEVELOP AND BE IN THE VICINITY BY AROUND 12Z. NOT ENOUGH CONFIDENCE TO GO WITH TSTMS IN THE MORNING. ANOTHER ROUND OF SHOWERS WITH A BETTER CHANCE OF EMBEDDED TSTMS IS ANTICIPATED LATE THIS AFTERNOON INTO THE EVENING AHEAD OF AN APPROACHING WEAK COLD FRONT. LOCAL MVFR TO IFR CONDITIONS POSSIBLE DURING THIS TIME. SHOWERS/TSTMS STILL POSSIBLE AT ANY POINT THIS AFTERNOON...HOWEVER...NOT ENOUGH CONFIDENCE IN GOING WITH A PREVAILING MENTION OF EITHER BEFORE THE TIMING OF THE PROB30 GROUPS. OUTLOOK FOR 06Z MON THROUGH THU... .SUN NIGHT...CONTINUED CHANCE OF MVFR/IFR CONDITIONS IN ANY SHOWERS/TSTMS. .MON-TUE...VFR. .WED...SCT AFTERNOON SHOWERS/TSTMS. .THU...VFR. && .MARINE... MAINLY SW TO WSW FLOW 10-15 KT ACROSS THE OPEN OCEAN WATERS...AND 5-10 KT ELSEWHERE THROUGH WEDNESDAY. OCCASIONAL GUSTS JUST BELOW 25 KT ARE POSSIBLE IN THE NY BIGHT REGION AND NEAR SHORE THIS AFTERNOON INTO THIS EVENING. WAVEWATCH SEAS APPEAR A LITTLE OVERDONE LATE THIS AFTERNOON INTO TONIGHT. AS A RESULT HAVE CAPPED OCEAN SEAS AT 4 FT THROUGH TONIGHT. SEAS THEREAFTER PRIMARILY 2 TO 4 FT. THUNDERSTORMS WILL BE POSSIBLE MAINLY LATE THIS AFTERNOON AND TONIGHT...AND ONCE AGAIN WEDNESDAY AFTERNOON AND NIGHT AS A COLD FRONT APPROACHES AND PASSES THROUGH. WINDS SHIFT NORTHERLY BEHIND THE FRONT ON THURSDAY WITH PERHAPS A WEAK ONSHORE FLOW DEVELOPING LOCALLY DURING THE AFTERNOON. && .HYDROLOGY... WHILE BASIN AVG QPF FROM LATE TONIGHT THROUGH SUNDAY NIGHT RUNS FROM AROUND 1/3 TO 3/4 INCH...HIGHEST NW OF NYC AND LOWEST OVER ERN CT/LONG ISLAND...LOCALLY HEAVY RAINFALL OF 1-2 INCHES OR MORE IS POSSIBLE UNDER ANY STRONGER CONVECTION GIVEN THE FORECAST NEAR- TROPICAL NATURE OF THE ATMOSPHERE...AS CONVECTION WILL BE VERY EFFICIENT IN CONVERTING AVAILABLE MOISTURE TO RAINFALL. THERE IS FAIRLY HIGH POTENTIAL FOR MINOR URBAN/POOR DRAINAGE/SMALL STREAM FLOODING. LOCALIZED FLASH FLOODING CANNOT BE RULED OUT...ESPECIALLY IN AREAS THAT EXPERIENCE MULTIPLE ROUNDS OF HEAVY RAIN...BUT THE FLASH FLOOD THREAT PROBABILITY/COVERAGE BOTH APPEAR TOO SMALL TO WARRANT A FLASH FLOOD WATCH. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...NONE. && $$
AREA FORECAST DISCUSSION
NWS ALBANY NY
215 AM EDT SUN JUL 15 2012 .SYNOPSIS... AN UPPER LEVEL DISTURBANCE IN THE OHIO VALLEY AND GREAT LAKES WILL BRING A CHANCE OF BENEFICIAL SHOWERS AND POSSIBLY THUNDERSTORMS TODAY. HIGH PRESSURE WILL BUILD FROM THE OHIO VALLEY MONDAY AND TUESDAY WITH MAINLY SUNNY HOT CONDITIONS. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... AS OF 130 AM...REGIONAL RADARS INDICATED CONVECTION IN PA WILL LIKELY REMAIN OUT OF OUR REGION THROUGH ABOUT 12Z. THEREFORE WENT AHEAD AND REMOVED POPS UNTIL THEN. IT SHOULD BE NOTED THAT THE LATEST HRRR EXPERIMENTAL MODEL DID BRING A CLUSTER OF SHOWERS INTO THE SCHOHARIE VALLEY AT 10Z...BUT THEN DISSIPATED THEM RIGHT AFTER THAT. NOT BUYING INTO THIS SOLUTION. SOME HIGH CLOUDINESS OVER THE REGION AND WAS GENERALLY THICKENING. MANY SPOTS STILL REPORTING A BREEZE AROUND 5 MPH OR SO. DECIDED TO RAISE TEMPS 1-3 DEGS IN A FEW SPOTS OVERNIGHT. UPSTREAM CLOUDS WERE THICKENING EVEN MORE ACROSS THE GREAT LAKES WHERE A PRETTY POTENT SHORT WAVE WAS. THIS WILL BE THE SYSTEM TO AFFECT OUR REGION LATER TODAY. && .SHORT TERM /6 AM THIS MORNING THROUGH TUESDAY/... RELATIVELY WELL DEFINED UPPER IMPULSE PREDICTED BY GUIDANCE AND ENSEMBLES TO TRACK THROUGH THE REGION SUNDAY. WHILE CONVECTION HAS DIMINISHED FROM EARLIER...A LOT OF MID LEVEL CLOUDS INDICATED LOTS OF DEEP LAYER MOISTURE. THERE SHOULD BE MORE CLOUDS THAN SUN SUNDAY WITH LIKELY SHOWERS AND THUNDERSTORMS BY MIDDAY. DID TEMPER THE POPS BACK A LITTLE DURING THE MORNING. LOW LEVEL JET ENERGY IS RELATIVELY WEAK...AND THERE SHOULD BE VERY LITTLE THERMAL FORCING...SO CONVECTION SHOULD BE MOSTLY HEAVY RAINERS...ALTHOUGH WITH THE INSTABILITY IN PLACE...AND SOME BREAKS IN THE CLOUDS...ALONG WITH HIGHS IN THE 80S IN MOST AREAS...SOME VERY ISOLATED STRONG WINDS AND HAIL ARE POSSIBLE. ANY AREAS THAT COULD SEE A PROLONGED PERIOD OF SUN COULD SEE HIGHS AROUND 90...BUT THAT LOOKS INCREASINGLY UNLIKELY THAT TEMPS WOULD GET THAT HIGH. GUIDANCE SUGGESTS THE UPPER SYSTEM IS PREDICTED TO EXIT THE REGION SUNDAY NIGHT INTO MONDAY...BUT STAY TUNED AS GUIDANCE OFTEN DOES NOT TIME THE MOVEMENT OF CONVECTIVELY BASED SYSTEMS WELL. THE WARM AND HUMID AIRMASS SHOULD STILL BE OVER THE REGION...BUT NO ORGANIZED LOW LEVEL FOCUS OTHER THAN OLD OUFLOW BOUNDARIES. SO...GRADUAL CLEARING...AND MAYBE SOME FOG SUNDAY NIGHT...THEN CONTINUED DECREASING CLOUDS MONDAY... WITH JUST VERY ISOLATED THUNDERSTORMS POSSIBLE...NOT ENOUGH TO ACKNOWLEDGE IN FORECAST YET. HIGHS IN THE 80S TO MID 90S. ANOTHER WARM AND HUMID NIGHT MONDAY NIGHT WITH LOWS IN THE 60S TO NEAR 70. SOME SLIGHT WARMING OF THE BOUNDARY LAYER WELL AHEAD OF THE NEXT APPROACHING SYSTEM. LOW LEVEL JET ENERGY GRADUALLY INCREASES... ESPECIALLY IN NORTHERN AREAS BY LATER TUESDAY AFTERNOON. SOME ISOLATED THUNDERSTORMS ARE POSSIBLE...ESPECIALLY IN AREAS OF TERRAIN. HIGHS AGAIN WELL INTO THE 80S TO LOWER 90S. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... HAVE GENERALLY POPULATED THIS PORTION OF GRIDDED DATABASE WITH A 50/50 BLEND OF 18Z HPC MOS...AND 12Z/GMOS. TUE NT-WED NT...BROAD UPPER LEVEL TROUGH IS EXPECTED TO DEVELOP ACROSS EAST CENTRAL CANADA EXTENDING INTO THE EASTERN GREAT LAKES...WITH AN ATTENDANT SFC COLD FRONT APPROACHING FROM THE GREAT LAKES DURING THIS PERIOD. THERE ARE SOME TIMING DIFFERENCES IN SFC FROPA ACROSS THE REGION...WITH THE 12Z/GFS SLIGHTLY FASTER...OCCURRING MIDDAY TUESDAY FROM ALBANY N AND W...AND THE AFTERNOON TO THE S/E...AND THE 12Z/ECMWF A BIT SLOWER...GEN RALLY DURING THE AFTERNOON/EVENING HOURS. WILL INDICATE CHC POPS FOR MUCH OF THE DAY...ALTHOUGH WILL TAPER ACROSS NW AREAS LATER IN THE DAY WITH EXPECTATION FOR MAIN FROPA TO OCCUR EARLIER. FOR WED NT...WILL KEEP SOME POPS THROUGH THE EVENING HOURS FOR AREAS S/E OF ALBANY...TO ACCOUNT FOR POSSIBILITY OF SLIGHTLY SLOWER FROPA. OTHERWISE...EXPECT A VERY WARM/HUMID NIGHT TUE NT/EARLY WED AM...WITH MINS ONLY FALLING INTO THE UPPER 60S TO LOWER 70S ACROSS MUCH OF THE HUDSON RIVER VALLEY AND MOHAWK RIVER VALLEY...WITH LOWER/MID 60S ELSEWHERE. ON WED...GENERALLY EXPECT MAXES TO REACH 85-90 IN THE HUDSON RIVER VALLEY FROM ALBANY SOUTH...AND 80-85 NORTH...WITH GENERALLY UPPER 70S TO MID 80S ELSEWHERE. SOME AREAS COULD BE WARMER FROM ALBANY S AND E SHOULD MORE SUNSHINE OCCUR WED AM THAN CURRENTLY EXPECTED. BY WED NT/THU AM...EXPECT SOMEWHAT COOLER/LESS HUMID CONDITIONS TO FILTER INTO THE REGION...WITH MINS FALLING TO 60-65 WITHIN THE HUDSON RIVER VALLEY/MOHAWK RIVER VALLEYS...AND 55-60 ELSEWHERE...ALTHOUGH SOME LOWER 50S WILL BE POSSIBLE WITHIN PORTIONS OF THE SOUTHERN ADIRONDACKS. THU-SAT...EXPECT DRY CONDITIONS...AS A SFC HIGH SLOWLY BUILDS INTO THE REGION FROM THE GREAT LAKES. TEMPS MAY EVEN BE A BIT BELOW SEASONAL LEVELS THU-FRI...GIVEN POTENTIAL 850 TEMPS FALLING INTO THE +8 TO +10C RANGE...BEFORE WARMING TO NEAR OR ABOVE NORMAL BY FRI-SAT. THIS TRANSLATES INTO MAX TEMPS IN THE UPPER 70S/LOWER 80S IN VALLEYS THU...AND LOWER/MID 80S FRI-SAT...WITH OVERNIGHT MINS FALLING INTO THE 50S IN MOST AREAS...WITH SOME 40S POSSIBLE ACROSS PORTIONS OF THE SOUTHERN ADIRONDACKS/NORTH COUNTRY FRI AM. && .AVIATION /06Z SUNDAY THROUGH THURSDAY/... MAINLY VFR CONDITIONS ARE EXPECTED AT THE KALB/KGFL/KPOU/KPSF TAF SITES UNTIL AN UPPER LEVEL DISTURBANCE BEGIN TO IMPACT THE REGION BEGINING AROUND NOON SUNDAY AND CONTINUING INTO SUNDAY EVENING. THERE COULD BE SOME MVFR FOG AT DURING THE REST OF TONIGHT AT KGFL AND KPSF AND TEMPO GROUPS HAVE BEEN INCLUDED AT THESE LOCATIONS TO ACCOUNT FOR THAT POSSIBLITY. AS THE UPPER LEVEL TROF APPROACHES...SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS WILL SPREAD ACROSS THE REGION OCCASIONAL REDUCTIONS INTO THE MVFR RANGE IS LIKELY AT ALL THE TAF SITES...AND IFR CONDITIONS ARE NOT OUT OF THE QUESTION...BUT FOR NOW HAVE NOT BEEN INCLUDED IN THE FORECAST. HAVE INCLUDED VCTS FOR ALL TAF SITES SUNDAY AFTERNOON...GENERALLY BETWEEN 19Z SUNDAY AND 01Z MONDAY DUE TO THE SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS THAT ARE EXPECTED. CALM OR LIGHT SOUTH WINDS FOR THE REST OF TONIGHT...THEN BECOMING SOUTH TO SOUTHWEST AT 5-10 KT LATE SUNDAY MORNING INTO THE AFTERNOON. WINDS WILL BE STRONGER...AND VARIABLE IN DIRECTION IN AND NEAR ANY THUNDERSTORMS. OUTLOOK... SUN NT...MVFR...CHC IFR...SHWRS AND TSTRMS. MON-WED...VFR/MVFR. ISOLD-SCT SHOWERS/TSTMS. && .FIRE WEATHER... AN UPPER LEVEL DISTURBANCE IN THE OHIO VALLEY AND GREAT LAKES WILL BRING A CHANCE OF SIGNIFICANT SHOWERS AND POSSIBLY THUNDERSTORMS ON SUNDAY. MORE ISOLATED TO SCATTERED THUNDERSTORMS ARE POSSIBLE THROUGH WEDNESDAY AS A WARM AND HUMID AIRMASS STAYS OVER OUR REGION. THE DISTURBANCE ON SUNDAY SHOULD BRING SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS AND HUMID CONDITIONS. THIS SYSTEM HAS THE POTENTIAL TO BRING 0.25 INCHES OR MORE...MAINLY SOUTH OF ALBANY. HIGH PRESSURE WILL BUILD EAST FROM THE OHIO VALLEY INTO OUR REGION ON MONDAY...BRINGING MORE HOT WEATHER. RELATIVE HUMIDITY VALUES WILL RECOVER TO 80 TO 100 PERCENT TONIGHT...AND REMAIN ELEVATED 60 TO 80 PERCENT MOST OF SUNDAY. HUMIDITY VALUES WILL REMAIN ELEVATED THROUGH MONDAY...DESPITE NO MORE RAIN EXPECTED. ONLY ISOLATED THUNDERSTORMS ARE EXPECTED MONDAY AND TUESDAY WITH POSSIBLY MORE SIGNIFICANT ACTIVITY ON WEDNESDAY. THE SURFACE WIND WILL BE LIGHT AND VARIABLE AND GENERALLY 10 MPH OR LESS. LOCALLY HIGHER GUSTS ARE POSSIBLE WITH ANY THUNDERSTORM. && .HYDROLOGY... NO SIGNIFICANT HYDRO PROBLEMS ARE EXPECTED FOR THE NEXT FIVE DAYS. SCATTERED SHOWERS AND THUNDERSTORMS...MAINLY IN AREAS OF TERRAIN THIS AFTERNOON...COULD PRODUCE VERY LOCALIZED AMOUNTS OVER HALF AN INCH. HOWEVER...RAINFALL BASIN AVERAGE WILL REMAIN WELL BELOW 0.25 INCHES WITH NO EFFECT ON THE SLUGGISH WATERSHEDS. THERE IS POTENTIAL FOR A AVERAGE RIVER BASIN QUARTER INCH OR MORE OF RAINFALL...MAINLY SOUTH OF ALBANY ON SUNDAY. SOME LOCALITIES COULD RECEIVE OVER AN INCH OF RAINFALL FROM DOWNPOURS. FURTHER NORTH...FROM ALBANY NORTHWARD...IT LOOKS AS LESS THAN A QUARTER OF AN INCH OF RAIN WILL FALL ACROSS THE RIVER BASIN. EITHER WAY...EVEN THESE RAIN WILL BE ONLY MINOR RELIEF FROM OUR INCREASE DRY SPELL...WITH NO RISES ON ANY RIVERS EXPECTED. AFTER SUNDAY...OUR NEXT CHANCE OF ANY REAL SHOWERS AND STORMS WILL BE LATE TUESDAY OR EARLY WEDNESDAY WITH THE PASSAGE OF A PRETTY STRONG COLD FRONT FOR THE TIME OF YEAR. 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/KL SHORT TERM...HWJIV/NAS LONG TERM...KL AVIATION...GJM FIRE WEATHER...NAS HYDROLOGY...NAS
AREA FORECAST DISCUSSION
NWS ALBANY NY
150 AM EDT SUN JUL 15 2012 .SYNOPSIS... AN UPPER LEVEL DISTURBANCE IN THE OHIO VALLEY AND GREAT LAKES WILL BRING A CHANCE OF BENEFICIAL SHOWERS AND POSSIBLY THUNDERSTORMS TODAY. HIGH PRESSURE WILL BUILD FROM THE OHIO VALLEY MONDAY AND TUESDAY WITH MAINLY SUNNY HOT CONDITIONS. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... AS OF 130 AM...REGIONAL RADARS INDICATED CONVECTION IN PA WILL LIKELY REMAIN OUT OF OUR REGION THROUGH ABOUT 12Z. THEREFORE WENT AHEAD AND REMOVED POPS UNTIL THEN. IT SHOULD BE NOTED THAT THE LATEST HRRR EXPERIMENTAL MODEL DID BRING A CLUSTER OF SHOWERS INTO THE SCHOHARIE VALLEY AT 10Z...BUT THEN DISSIPATED THEM RIGHT AFTER THAT. NOT BUYING INTO THIS SOLUTION. SOME HIGH CLOUDINESS OVER THE REGION AND WAS GENERALLY THICKENING. MANY SPOTS STILL REPORTING A BREEZE AROUND 5 MPH OR SO. DECIDED TO RAISE TEMPS 1-3 DEGS IN A FEW SPOTS OVERNIGHT. UPSTREAM CLOUDS WERE THICKENING EVEN MORE ACROSS THE GREAT LAKES WHERE A PRETTY POTENT SHORT WAVE WAS. THIS WILL BE THE SYSTEM TO AFFECT OUR REGION LATER TODAY. && .SHORT TERM /6 AM THIS MORNING THROUGH TUESDAY/... RELATIVELY WELL DEFINED UPPER IMPULSE PREDICTED BY GUIDANCE AND ENSEMBLES TO TRACK THROUGH THE REGION SUNDAY. WHILE CONVECTION HAS DIMINISHED FROM EARLIER...A LOT OF MID LEVEL CLOUDS INDICATED LOTS OF DEEP LAYER MOISTURE. THERE SHOULD BE MORE CLOUDS THAN SUN SUNDAY WITH LIKELY SHOWERS AND THUNDERSTORMS BY MIDDAY. DID TEMPER THE POPS BACK A LITTLE DURING THE MORNING. LOW LEVEL JET ENERGY IS RELATIVELY WEAK...AND THERE SHOULD BE VERY LITTLE THERMAL FORCING...SO CONVECTION SHOULD BE MOSTLY HEAVY RAINERS...ALTHOUGH WITH THE INSTABILITY IN PLACE...AND SOME BREAKS IN THE CLOUDS...ALONG WITH HIGHS IN THE 80S IN MOST AREAS...SOME VERY ISOLATED STRONG WINDS AND HAIL ARE POSSIBLE. ANY AREAS THAT COULD SEE A PROLONGED PERIOD OF SUN COULD SEE HIGHS AROUND 90...BUT THAT LOOKS INCREASINGLY UNLIKELY THAT TEMPS WOULD GET THAT HIGH. GUIDANCE SUGGESTS THE UPPER SYSTEM IS PREDICTED TO EXIT THE REGION SUNDAY NIGHT INTO MONDAY...BUT STAY TUNED AS GUIDANCE OFTEN DOES NOT TIME THE MOVEMENT OF CONVECTIVELY BASED SYSTEMS WELL. THE WARM AND HUMID AIRMASS SHOULD STILL BE OVER THE REGION...BUT NO ORGANIZED LOW LEVEL FOCUS OTHER THAN OLD OUFLOW BOUNDARIES. SO...GRADUAL CLEARING...AND MAYBE SOME FOG SUNDAY NIGHT...THEN CONTINUED DECREASING CLOUDS MONDAY... WITH JUST VERY ISOLATED THUNDERSTORMS POSSIBLE...NOT ENOUGH TO ACKNOWLEDGE IN FORECAST YET. HIGHS IN THE 80S TO MID 90S. ANOTHER WARM AND HUMID NIGHT MONDAY NIGHT WITH LOWS IN THE 60S TO NEAR 70. SOME SLIGHT WARMING OF THE BOUNDARY LAYER WELL AHEAD OF THE NEXT APPROACHING SYSTEM. LOW LEVEL JET ENERGY GRADUALLY INCREASES... ESPECIALLY IN NORTHERN AREAS BY LATER TUESDAY AFTERNOON. SOME ISOLATED THUNDERSTORMS ARE POSSIBLE...ESPECIALLY IN AREAS OF TERRAIN. HIGHS AGAIN WELL INTO THE 80S TO LOWER 90S. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... HAVE GENERALLY POPULATED THIS PORTION OF GRIDDED DATABASE WITH A 50/50 BLEND OF 18Z HPC MOS...AND 12Z/GMOS. TUE NT-WED NT...BROAD UPPER LEVEL TROUGH IS EXPECTED TO DEVELOP ACROSS EAST CENTRAL CANADA EXTENDING INTO THE EASTERN GREAT LAKES...WITH AN ATTENDANT SFC COLD FRONT APPROACHING FROM THE GREAT LAKES DURING THIS PERIOD. THERE ARE SOME TIMING DIFFERENCES IN SFC FROPA ACROSS THE REGION...WITH THE 12Z/GFS SLIGHTLY FASTER...OCCURRING MIDDAY TUESDAY FROM ALBANY N AND W...AND THE AFTERNOON TO THE S/E...AND THE 12Z/ECMWF A BIT SLOWER...GEN RALLY DURING THE AFTERNOON/EVENING HOURS. WILL INDICATE CHC POPS FOR MUCH OF THE DAY...ALTHOUGH WILL TAPER ACROSS NW AREAS LATER IN THE DAY WITH EXPECTATION FOR MAIN FROPA TO OCCUR EARLIER. FOR WED NT...WILL KEEP SOME POPS THROUGH THE EVENING HOURS FOR AREAS S/E OF ALBANY...TO ACCOUNT FOR POSSIBILITY OF SLIGHTLY SLOWER FROPA. OTHERWISE...EXPECT A VERY WARM/HUMID NIGHT TUE NT/EARLY WED AM...WITH MINS ONLY FALLING INTO THE UPPER 60S TO LOWER 70S ACROSS MUCH OF THE HUDSON RIVER VALLEY AND MOHAWK RIVER VALLEY...WITH LOWER/MID 60S ELSEWHERE. ON WED...GENERALLY EXPECT MAXES TO REACH 85-90 IN THE HUDSON RIVER VALLEY FROM ALBANY SOUTH...AND 80-85 NORTH...WITH GENERALLY UPPER 70S TO MID 80S ELSEWHERE. SOME AREAS COULD BE WARMER FROM ALBANY S AND E SHOULD MORE SUNSHINE OCCUR WED AM THAN CURRENTLY EXPECTED. BY WED NT/THU AM...EXPECT SOMEWHAT COOLER/LESS HUMID CONDITIONS TO FILTER INTO THE REGION...WITH MINS FALLING TO 60-65 WITHIN THE HUDSON RIVER VALLEY/MOHAWK RIVER VALLEYS...AND 55-60 ELSEWHERE...ALTHOUGH SOME LOWER 50S WILL BE POSSIBLE WITHIN PORTIONS OF THE SOUTHERN ADIRONDACKS. THU-SAT...EXPECT DRY CONDITIONS...AS A SFC HIGH SLOWLY BUILDS INTO THE REGION FROM THE GREAT LAKES. TEMPS MAY EVEN BE A BIT BELOW SEASONAL LEVELS THU-FRI...GIVEN POTENTIAL 850 TEMPS FALLING INTO THE +8 TO +10C RANGE...BEFORE WARMING TO NEAR OR ABOVE NORMAL BY FRI-SAT. THIS TRANSLATES INTO MAX TEMPS IN THE UPPER 70S/LOWER 80S IN VALLEYS THU...AND LOWER/MID 80S FRI-SAT...WITH OVERNIGHT MINS FALLING INTO THE 50S IN MOST AREAS...WITH SOME 40S POSSIBLE ACROSS PORTIONS OF THE SOUTHERN ADIRONDACKS/NORTH COUNTRY FRI AM. && .AVIATION /06Z SUNDAY THROUGH THURSDAY/... VFR CONDITIONS ARE EXPECTED EARLY THIS EVENING. THEN...EXPECT AREAS OF MVFR VSBYS TO DEVELOP DUE TO BR. THERE IS A SLIGHT CHANCE THAT PATCHY GROUND FOG AND IFR VSBYS COULD DEVELOP AFTER 07Z...ESP AT KGFL AND KPSF...BUT OVERALL PROBABILITY TOO LOW TO MENTION IN CURRENT TAFS. ANY AREAS OF MVFR/IFR VSBYS SHOULD GIVE WAY TO VFR CONDITIONS SUNDAY MORNING. HOWEVER...AS SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS DEVELOP IN THE AFTERNOON...SOME REDUCTIONS INTO THE MVFR/IFR RANGE ARE POSSIBLE. HAVE INCLUDED MENTION OF VCTS FOR ALL TAF SITES SUNDAY AFTERNOON...AS SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ARE EXPECTED. LIGHT SOUTH WINDS WILL BECOME NEARLY CALM OVERNIGHT. WINDS WILL BECOME SOUTH TO SOUTHWEST AT 5-10 KT LATE SUNDAY MORNING INTO THE AFTERNOON. WINDS WILL BE STRONGER...AND VARIABLE IN DIRECTION IN AND NEAR ANY THUNDERSTORMS. OUTLOOK... SUN NT...MVFR...CHC IFR...SHWRS AND TSTRMS. MON-WED...VFR/MVFR. ISOLD-SCT SHOWERS/TSTMS. && .FIRE WEATHER... AN UPPER LEVEL DISTURBANCE IN THE OHIO VALLEY AND GREAT LAKES WILL BRING A CHANCE OF SIGNIFICANT SHOWERS AND POSSIBLY THUNDERSTORMS ON SUNDAY. MORE ISOLATED TO SCATTERED THUNDERSTORMS ARE POSSIBLE THROUGH WEDNESDAY AS A WARM AND HUMID AIRMASS STAYS OVER OUR REGION. THE DISTURBANCE ON SUNDAY SHOULD BRING SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS AND HUMID CONDITIONS. THIS SYSTEM HAS THE POTENTIAL TO BRING 0.25 INCHES OR MORE...MAINLY SOUTH OF ALBANY. HIGH PRESSURE WILL BUILD EAST FROM THE OHIO VALLEY INTO OUR REGION ON MONDAY...BRINGING MORE HOT WEATHER. RELATIVE HUMIDITY VALUES WILL RECOVER TO 80 TO 100 PERCENT TONIGHT...AND REMAIN ELEVATED 60 TO 80 PERCENT MOST OF SUNDAY. HUMIDITY VALUES WILL REMAIN ELEVATED THROUGH MONDAY...DESPITE NO MORE RAIN EXPECTED. ONLY ISOLATED THUNDERSTORMS ARE EXPECTED MONDAY AND TUESDAY WITH POSSIBLY MORE SIGNIFICANT ACTIVITY ON WEDNESDAY. THE SURFACE WIND WILL BE LIGHT AND VARIABLE AND GENERALLY 10 MPH OR LESS. LOCALLY HIGHER GUSTS ARE POSSIBLE WITH ANY THUNDERSTORM. && .HYDROLOGY... NO SIGNIFICANT HYDRO PROBLEMS ARE EXPECTED FOR THE NEXT FIVE DAYS. SCATTERED SHOWERS AND THUNDERSTORMS...MAINLY IN AREAS OF TERRAIN THIS AFTERNOON...COULD PRODUCE VERY LOCALIZED AMOUNTS OVER HALF AN INCH. HOWEVER...RAINFALL BASIN AVERAGE WILL REMAIN WELL BELOW 0.25 INCHES WITH NO EFFECT ON THE SLUGGISH WATERSHEDS. THERE IS POTENTIAL FOR A AVERAGE RIVER BASIN QUARTER INCH OR MORE OF RAINFALL...MAINLY SOUTH OF ALBANY ON SUNDAY. SOME LOCALITIES COULD RECEIVE OVER AN INCH OF RAINFALL FROM DOWNPOURS. FURTHER NORTH...FROM ALBANY NORTHWARD...IT LOOKS AS LESS THAN A QUARTER OF AN INCH OF RAIN WILL FALL ACROSS THE RIVER BASIN. EITHER WAY...EVEN THESE RAIN WILL BE ONLY MINOR RELIEF FROM OUR INCREASE DRY SPELL...WITH NO RISES ON ANY RIVERS EXPECTED. AFTER SUNDAY...OUR NEXT CHANCE OF ANY REAL SHOWERS AND STORMS WILL BE LATE TUESDAY OR EARLY WEDNESDAY WITH THE PASSAGE OF A PRETTY STRONG COLD FRONT FOR THE TIME OF YEAR. 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/KL SHORT TERM...HWJIV/NAS LONG TERM...KL AVIATION...KL/BGM FIRE WEATHER...NAS HYDROLOGY...NAS
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
454 AM EDT Sun Jul 15 2012 .NEAR TERM [Through Today]... A rather amplified and complex upper level pattern is depicted this morning by the 05z RAP analysis. Two shortwave troughs across the Pacific Northwest and the Upper Midwest are complimented by two ridges across the Plains states and the Southeast states. Pinched off from the easternmost trough is a weak closed low centered over the Southern Plains. Finally, a TUTT draped across the western Caribbean, northeast into the western Atlantic, continues its slow westward progression. For this afternoon, subsidence provided by the southeastern U.S. ridge will provide our local area with slightly drier conditions. That being said, precipitable water levels are expected to remain at or slightly above climatological normals for this time of year. With no large scale support for ascent expected, the local seabreeze fronts will dominate this afternoon`s weather pattern. With slightly more easterly flow regime expected today, a slightly modified regime 2 is expected. This regime would favor the Panhandle Seabreeze Front and the East Coast Seabreeze Front. Thus PoPs are highest across the Florida Panhandle, and later across our eastern counties in Georgia and Florida. With respect to the threat for severe weather, no severe weather is expected across our Florida counties this afternoon. Lower than normal instability coupled with several other poor to marginal thermodynamic variables will be the limiting factors here. There does exist a slight chance for severe storms across our Georgia and Alabama counties today, with a few caveats. Drier mid-level air will increase the theta-e differences between the middle and lower troposphere. This coupled with steep low level lapse rates will increase the threat for severe downbursts. However, the dry air may also be the limiting factor in storm development. The best case scenario for severe storm development across Georgia would be late in the afternoon/early evening when the East Coast Seabreeze enters the primed atmosphere. The same story holds true for southeast Alabama, with a different forcing mechanism. Any storms that for across Alabama will likely be due to boundary interactions from the Panhandle Seabreeze. A late afternoon/early evening threat timeline is expected across Alabama as well. Waterspouts will be possible again today, primarily along eastward facing Big Bend beaches due to the more easterly wind component. The threat should diminish by the afternoon with the diminishing wind enhancement behind yesterday`s East Coast Seabreeze Front. && .SHORT TERM [Tonight Through Tuesday]... Seabreeze circulations will continue to influence the precipitation pattern through the remainder of the short term. However, beginning Monday, the aforementioned TUTT will move southwest into our eastern forecast area. This will especially enhance PoPs across north Florida, east of the Apalachicola River. On Tuesday, the trough will overspread our entire forecast area enhancing PoPs area wide. Temperatures will hold near climatological averages in the lower 90s each afternoon, and the lower 70s each night. && .LONG TERM [Tuesday Night through Sunday]... Very little change to the extended fcst this cycle as the latest 00 UTC GFS and ECMWF have remained in fairly good agreement with a Synoptic pattern dominated by a TUTT Low which will gradually open up into an Upper Level Trof. This should further increase fcst confidence in above Climo Pops and near Climo Max Temps through much of the period. Despite the fairly disturbed pattern, the MEX High Temps appeared too high (Mid 90s in many areas away from the coast) for the expected levels of cloud cover and rain chances, so used a 2-1 Blend of the lower and more realistic looking HPC and MOS Guidance grids. The Euro (and GFS to some extent) do both show some potential for a brief break in this pattern on Friday, with possible Upper Level Ridging moving in from the east, before the mean Trof builds back southward over the weekend, bringing a return to higher rain chances. && .AVIATION... A bit more of a challenging Taf package for the overnight and early morning hours than last night, as the numerical guidance (which is fairly pessimistic at many of the Terminals) is split with the Hi-Res models which are generally keeping VFR conditions through the night. Although conditions could worsen a bit more than expected with no Cirrus Canopy tonight, decided on only tempo MVFR conditions at DHN and ABY for this package. On Sunday, expect the convective coverage to be lower than Saturday with the more of an easterly flow developing, so only went with Prob30s at ECP and VLD, with VCTS at TLH, and just VFR the rest of the day at ABY and DHN. && .MARINE... Winds and seas will remain below headline criteria for the next several days as the subtropical ridge keeps a firm hold on the region. Enhancements nearing SCEC criteria are possible this morning and tomorrow morning along the East Coast Seabreeze Front. Flow will shift more southerly by Tuesday, effectively ending the East Coast Seabreeze enhancements. && .FIRE WEATHER... Still no fire weather concerns in sight over the foreseeable future across the Tri-State area, as ample low-level moisture will keep afternoon relative humidities fairly high through the period. && .TAE WATCHES/WARNINGS/ADVISORIES... FL...None. GA...None. AL...None. MARINE...None. && $$ NEAR TERM...Harrigan SHORT TERM...Harrigan LONG TERM...Gould AVIATION...Gould MARINE...Harrigan FIRE WEATHER...Gould
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
323 AM EDT Sun Jul 15 2012 .NEAR TERM [Through Today]... A rather amplified and complex upper level pattern is depicted this morning by the 05z RAP analysis. Two shortwave troughs across the Pacific Northwest and the Upper Midwest are complimented by two ridges across the Plains states and the Southeast states. Pinched off from the easternmost trough is a weak closed low centered over the Southern Plains. Finally, a TUTT draped across the western Caribbean, northeast into the western Atlantic, continues its slow westward progression. For this afternoon, subsidence provided by the southeastern U.S. ridge will provide our local area with slightly drier conditions. That being said, precipitable water levels are expected to remain at or slightly above climatological normals for this time of year. With no large scale support for ascent expected, the local seabreeze fronts will dominate this afternoon`s weather pattern. With slightly more easterly flow regime expected today, a slightly modified regime 2 is expected. This regime would favor the Panhandle Seabreeze Front and the East Coast Seabreeze Front. Thus PoPs are highest across the Florida Panhandle, and later across our eastern counties in Georgia and Florida. With respect to the threat for severe weather, no severe weather is expected across our Florida counties this afternoon. Lower than normal instability coupled with several other poor to marginal thermodynamic variables will be the limiting factors here. There does exist a slight chance for severe storms across our Georgia and Alabama counties today, with a few caveats. Drier mid-level air will increase the theta-e differences between the middle and lower troposphere. This coupled with steep low level lapse rates will increase the threat for severe downbursts. However, the dry air may also be the limiting factor in storm development. The best case scenario for severe storm development across Georgia would be late in the afternoon/early evening when the East Coast Seabreeze enters the primed atmosphere. The same story holds true for southeast Alabama, with a different forcing mechanism. Any storms that for across Alabama will likely be due to boundary interactions from the Panhandle Seabreeze. A late afternoon/early evening threat timeline is expected across Alabama as well. Waterspouts will be possible again today, primarily along eastward facing Big Bend beaches due to the more easterly wind component. The threat should diminish by the afternoon with the passage of yesterday`s East Coast Seabreeze Front. && .SHORT TERM [Tonight Through Tuesday]... Seabreeze circulations will continue to influence the precipitation pattern through the remainder of the short term. However, beginning Monday, the aforementioned TUTT will move southwest into our eastern forecast area. This will especially enhance PoPs across north Florida, east of the Apalachicola River. On Tuesday, the trough will overspread our entire forecast area enhancing PoPs area wide. Temperatures will hold near climatological averages in the lower 90s each afternoon, and the lower 70s each night. && .LONG TERM [Tuesday Night through Sunday]... Updating shortly... && .AVIATION... A bit more of a challenging Taf package for the overnight and early morning hours than last night, as the numerical guidance (which is fairly pessimistic at many of the Terminals) is split with the Hi-Res models which are generally keeping VFR conditions through the night. Although conditions could worsen a bit more than expected with no Cirrus Canopy tonight, decided on only tempo MVFR conditions at DHN and ABY for this package. On Sunday, expect the convective coverage to be lower than Saturday with the more of an easterly flow developing, so only went with Prob30s at ECP and VLD, with VCTS at TLH, and just VFR the rest of the day at ABY and DHN. && .MARINE... Winds and seas will remain below headline criteria for the next several days as the subtropical ridge keeps a firm hold on the region. Enhancements nearing SCEC criteria are possible this morning and tomorrow morning along the East Coast Seabreeze Front. Flow will shift more southerly by Tuesday, effectively ending the East Coast Seabreeze enhancements. && .FIRE WEATHER... Updating shortly... && .TAE WATCHES/WARNINGS/ADVISORIES... FL...None. GA...None. AL...None. MARINE...None. && $$ NEAR TERM...Harrigan SHORT TERM...Harrigan LONG TERM...Gould AVIATION...Gould MARINE...Harrigan FIRE WEATHER...Gould
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
409 AM CDT SUN JUL 15 2012 .DISCUSSION... 837 PM CDT CONVECTIVE ACTIVITY HAS SETTLED THIS EVENING AND SHOULD BE DRY THROUGH THE REMAINDER OF THE EVENING. HAVE TWEAKED POPS TO REFLECT DIMINISHED CHANCES. LATE TONIGHT ANOTHER MID LEVEL DISTURBANCE IS EXPECTED TO DROP SOUTH ACROSS THE AREA. ISOLATED THUNDERSTORMS ASSOCIATED WITH THIS WAVE HAVE ALREADY DEVELOPED OVER PORTIONS OF WISCONSIN...BUT OVERALL FORCING/MOISTURE CONVERGENCE APPEARS TO BE VERY WEAK AND DO NOT EXPECT MORE THAN ISOLATED COVERAGE IF ANY AS IT MOVES INTO NORTHERN ILLINOIS. OTHERWISE...ONLY MADE MINOR TWEAKS TO HOURLY TRENDS FOR T/TD...OVERALL FORECAST APPEARS ON TRACK. BMD //PREV DISCUSSION... 210 PM CDT CONCERNS WITH THE FORECAST ARE CENTERED ON CONVECTION THROUGH THIS EVENING...AND THEN HOT TEMPERATURES THE NEXT SEVERAL DAYS. SHORT TERM...REST OF THIS AFTERNOON THROUGH SUNDAY... TOWERING CUMULUS ALONG WITH SOME SCATTERED STORMS HAVE DEVELOPED EARLY THIS AFTERNOON ACROSS MAINLY THE EASTERN HALF OF THE FORECAST AREA ALONG AND AHEAD OF A SHEARED OUT UPPER IMPULSE AND AN ELEVATED /850-700MB/ WIND AND MOISTURE CONVERGENCE ZONE. GIVEN A FAIRLY UNSTABLE AIR MASS PER MODIFIED AMDAR SOUNDINGS AND RAP ANALYSIS...WITH MLCAPE VALUES OF 1000 TO 1500 J/KG...THESE STORMS SHOULD CONTINUE TO REGENERATE WITH THE FURTHER FOCI OF BOUNDARY INTERACTIONS. HAVE ALREADY SEEN THE DIVERGENT VELOCITY SIGNATURES ON RADAR UNDERNEATH THESE STORMS WITHIN JUST TWO RADAR VCPS...SHOWING THE DOWNDRAFT POTENTIAL ONCE AGAIN. ENVIRONMENTAL DCAPE VALUES ANALYZED BY THE RAP OF 700 TO 1000 J/KG ARE SLIGHTLY LESS THAN YESTERDAY...BUT SUFFICIENT ENOUGH FOR A POSSIBLE ISOLATED SEVERE GUST...INCLUDING IN NEARSHORE AREAS OF THE LAKE IN ANY STORMS THAT DRIFT NORTHEAST OVER THAT AREA. AN UPPER LEVEL SHORT WAVE...AS PART OF THE LARGER BROAD TROUGH...IS MOVING SOUTHEAST ACROSS WESTERN WI EARLY THIS AFTERNOON. THE INITIAL SURFACE BOUNDARY UNDERNEATH THIS IS HELPING TO FOCUS SOME SCATTERED STORMS...WITH SIMILAR ML INSTABILITY OF 1000 TO 1500 J/KG. MORE DEVELOPMENT IS ANTICIPATED THROUGH EARLY EVENING IN ADVANCE OF THIS AS CONVERGENCE IMPROVES...AND SOME OF THIS MAY POTENTIALLY BE ALONG OUTFLOW THAT IS ALREADY INTO NORTHWEST IL. EXPLICIT CONVECTIVE MODELS DO KEY IN ON SCATTERED STORM DEVELOPMENT TOWARD THE I-39 CORRIDOR BY LATE AFTERNOON. WITH THE SHORT WAVE AND FRONTAL APPROACH...ALONG WITH DEEP LAYER SHEAR VALUES OF SEMI-DECENT 30 KT PROJECTED...THESE SHOWERS AND STORMS HAVE POTENTIAL TO HANG ON LATER INTO THE EVENING. THE COOL FRONT WILL MOVE THROUGH THE AREA LATE TONIGHT AND SUNDAY MORNING...BUT WASHING OUT AS IT DOES. TEMPERATURES ON SUNDAY ARE ACTUALLY EXPECTED TO BE SLIGHTLY HIGHER THAN TODAY...AND DEW POINTS SHOULD BE CLOSE. THIS WILL AGAIN PROVIDE MODEST INSTABILITY...BUT HEIGHT RISES ALOFT SHOULD TEMPER STORM DEVELOPMENT. A ROGUE LATE AFTERNOON CELL OR TWO CANNOT BE RULED OUT ALONG WEAK SURFACE CONVERGENCE...BUT HAVE NOT MENTIONED IN THE FORECAST AT THIS TIME. HIGHS ON SUNDAY LOOK TO TOP OUT IN THE LOWER TO MID 90S...WITH A LAKE BREEZE PROVIDING SOME COOLING FOR DOWNTOWN CHICAGO AND NEARBY AREAS DURING THE AFTERNOON. THESE LAKE SHORE AREAS STILL MAY REACH 90 OR NEAR IT BEFORE THE LAKE BREEZE PUSHES THROUGH. MTF LONG TERM...SUNDAY NIGHT THROUGH SATURDAY... THE UPPER LEVEL RIDGE REESTABLISHES ITSELF ACROSS THE CENTRAL US AS THE TROUGH MOVES OFF TOWARD THE NEW ENGLAND AREA. A WEAKENING AREA OF LOW PRESSURE MOVES NORTH OF THE GREAT LAKES MONDAY NIGHT...WHILE ITS COLD FRONT SINKS SOUTH DOWN THE LAKE ON TUESDAY. PRECIP CHANCES DIMINISH AS THE TROUGH DRIFTS EASTWARD SUNDAY NIGHT. THE BEST CHANCE OF PRECIP IN THE EXTENDED IS ALONG THE COLD FRONT LATE TUESDAY THROUGH WEDNESDAY. GUIDANCE DIFFERS ON THE SPEED OF THE FRONT...WITH THE GFS BRINGING THE FRONT THROUGH MUCH FASTER THAN THE ECMWF. GIVEN ISSUES WITH THE GFS LATELY...AND THE ECMWF HAVING VERY CONSISTENT TIMING OVER THE PAST FEW DAYS...GOING WITH THE SLOWER SOLUTION. BOTH MODELS INDICATE MOISTURE WILL POOL ALONG THE FRONT...BUT THEN DISSIPATE AS THE FRONT ENTERS NORTHERN IL. THEREFORE...KEPT BEST PRECIP CHANCES NORTH OF I-80. LIMITED ACTUAL PRECIP CHANCES TO LESS THAN 50 PERCENT GIVEN THE MODEL TRENDS AND DRY CONDITIONS. HIGH PRESSURE BUILDS IN BEHIND THE FRONT...AND GUIDANCE SUGGESTS RANDOM PERIODS OF PRECIP DURING THE LATTER HALF OF NEXT WEEK. HOWEVER...WITH NO CLEAR SOURCE OF FORCING...QUESTIONABLE MOISTURE SOURCES...AND DROUGHT CONDITIONS...DECIDED TO KEEP THE REMAINDER OF THE EXTENDED DRY. AT THIS POINT THE BIGGER CRIME IS GETTING FOLKS HOPES UP FOR RAIN ONLY TO DISAPPOINT. HEAT BUILDS ACROSS THE REGION THROUGH TUESDAY. GUIDANCE SUGGESTS THERE WILL ONLY BE A SMALL PUSH OF SLIGHTLY COOLER AIR BEHIND THE FRONT...WITH WEDNESDAY LOOKING TO BE A BIT COOLER. HOWEVER 850 HPA TEMPS BEGIN TO WARM ALMOST IMMEDIATELY WITH THE UPPER LEVEL RIDGE SW OF THE CWA. THEREFORE...THE LATTER HALF OF NEXT WEEK LOOKS ABOVE AVERAGE. JEE && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 09Z... * LIGHT SOUTH WIND BECOMING SOUTHWEST OVERNIGHT. * VERY LOW PROBABILITY SHRA/TSRA POTENTIAL THROUGH MID MORNING. * WIND SHIFT FROM LIGHT WEST-SOUTHWEST TO EAST-NORTHEAST WITH WEAK TROUGH PASSAGE MID-LATE MORNING AND LAKE BREEZE PUSH FROM THE EAST THIS AFTERNOON. MDB //DISCUSSION...UPDATED 09Z... WEAK UPPER TROUGH/WEAK SURFACE FRONT CONTINUE TO APPROACH THE AREA FROM THE NORTHWEST. EARLIER SPOTTY CONVECTION ASSOCIATED WITH IT ACROSS CENTRAL/SOUTHERN WISCONSIN HAS DISSIPATED WITH LITTLE IN THE WAY OF CLOUD COVER BEING GENERATED BY THE WAVE AT THIS TIME. STILL EXPECT THAT THE TERMINALS WILL REMAIN DRY AS THESE FEATURES PASS BUT A NON-ZERO CHANCE FOR SOME ISOLATED DEVELOPMENT DOES EXIST BUT IS TOO LOW TO INCLUDE MENTION IN THE TAFS. MDB FROM 06Z... THE MAIN FORECAST CONCERNS ARE SLIM CHANCES FOR ISOLD SHRA/TSRA THROUGH DAYBREAK...AN OFF CHANCE THIS AFTERNOON...AND A LAKE BREEZE PUSHING INLAND DURING THE AFTERNOON. SATELLITE IMAGERY CONTINUES TO SHOW AN UPPER LEVEL TROUGH MOVING SOUTHEASTWARD ACROSS CENTRAL/SOUTHERN WISCONSIN EARLY TONIGHT. RADAR CONTINUES TO SHOW SOME SHRA/TSRA ACTIVITY AHEAD OF THIS WAVE ACROSS SOUTHERN WI BUT LATEST IMAGERY SHOWS A WEAKENING TREND TO THIS ACTIVITY. ENERGY ASSOCIATED WITH THE SHORTWAVE WILL REACH THE AREA IN THE NEXT 2-3 HOURS OR SO AND BRING A VERY LOW CHANCE FOR KICKING OFF SHRA/TSRA AS IT DOES SO. WILL CONTINUE TO LEAVE ANY PRECIP MENTION OUT OF THE TAFS WITH THE CHANCE FOR OCCURRENCE TOO LOW. SHOULD ANYTHING MAKE IT INTO NORTHERN ILLINOIS/NW INDIANA IT WOULD BE VERY ISOLATED. IN ADDITION...A WEAK SURFACE TROUGH WILL BE SETTLING ACROSS THE AREA LATER THIS MORNING. THIS MAY ALSO SERVE AS A FOCUS FOR SHRA/TSRA DEVELOPMENT DURING THE MID/LATE MORNING HOURS BUT THIS CHANCE IS ALSO VERY LOW. LIGHT WINDS FAVORING A SOUTHWESTERLY DIRECTION WILL TURN NORTHERLY AS THE SURFACE TROUGH PASSES MID/LATE MORNING. THE FLOW WILL REMAIN WEAK WHICH WILL SUPPORT THE DEVELOPMENT OF A LAKE BREEZE WHICH SHOULD MOVE FAIRLY FAR INLAND THIS AFTERNOON. WINDS WILL TURN EAST TO NORTHEAST AS THE LAKE BREEZE BOUNDARY PASSES. IT IS POSSIBLE THAT THE LAKE BREEZE COULD AID SOME SPOTTY TSRA DEVELOPMENT THIS AFTERNOON BUT WARMING OF THE MID LEVELS SHOULD PRECLUDE MUCH OF NOT ALL DEVELOPMENT THIS AFTERNOON. MDB //ORD AND MDW CONFIDENCE...UPDATED 09Z... * HIGH CONFIDENCE IN OVERALL WIND TRENDS. * MEDIUM-HIGH CONFIDENCE IN NO ADDITIONAL TSRA AT TERMINALS. * HIGH CONFIDENCE IN LAKE BREEZE OCCURRENCE THIS AFTERNOON. MDB //OUTLOOK FOR ORD/MDW FOR 12Z MONDAY-12Z SATURDAY...UPDATED 00Z... MONDAY...VFR. TUESDAY...VFR. CHANCE TSRA TUES NGT. WEDNESDAY...SLGT CHANCE TSRA. OTHERWISE VFR. THURSDAY AND FRIDAY...VFR. RATZER && .MARINE... 246 AM CDT A SERIES OF SYSTEMS WILL PASS NORTH OF LAKE MICHIGAN BETWEEN NOW AND WEDNESDAY...EACH BRINGING A COOL FRONTAL BOUNDARY DOWN THE LAKE. THE FIRST AREA OF LOW PRESSURE IS MOVING ACROSS EASTERN ONTARIO AND EXTENDS TOWARD NORTHERN LAKE MICHIGAN. A WEAK FRONT CONTINUES TO DROP SOUTHWARD DOWN THE LAKE AND WILL BE TO THE SOUTH BY LATE MORNING. HIGH PRESSURE THEN QUICKLY RETURNS BEHIND THE FRONT THIS AFTERNOON. WINDS WILL LIKELY BECOME LIGHT AND VARIABLE OR ONSHORE ACROSS MUCH OF THE CENTRAL AND SOUTHERN PART OF THE LAKE THIS AFTERNOON THEN BECOME SOUTHERLY ACROSS THE LAKE THIS EVENING. ANOTHER LOW PRESSURE SYSTEM TAKES SHAPE ACROSS THE DAKOTAS AND TURNS EASTWARD AND CROSSES LAKE SUPERIOR MONDAY EVENING. THIS LOW IS EXPECTED TO BE FAIRLY WELL ORGANIZED AND TIGHTENS THE PRESSURE GRADIENT ACROSS THE NORTHERN END OF THE LAKE LEADING TO A PERIOD OF 25-30 KT WINDS LATE MONDAY AFTERNOON AND MONDAY EVENING. AS THE LOW EXITS INTO SOUTHERN QUEBEC TUESDAY A COLD FRONT WILL MARCH DOWN THE LAKE BRINGING A SHIFT FROM BREEZY SOUTHERLY WINDS TO BREEZY NORTHWESTERLY WINDS. AT THIS POINT...SPEEDS ON THE BACK SIDE OF THE FRONT LOOK TO BE MODESTLY LOWER THAN THE WINDS AHEAD OF THE FRONT. WILL NEED TO WATCH FOR SMALL CRAFT ADVISORY CONDITIONS FROM WEDNESDAY AFTERNOON BUT AT THIS POINT IT SEEMS THAT CRITERIA WILL NOT BE MET...HOWEVER...THE LONG FETCH IN PLACE BEHIND THIS FRONT MAY ALLOW WAVES TO BUILD ENOUGH TO WARRANT ISSUANCE. HIGH PRESSURE THEN BUILDS IN WEDNESDAY NIGHT AND DRIFTS EASTWARD ACROSS MICHIGAN INTO FRIDAY NIGHT. ONCE THE STRONGER NORTH TO NORTHEAST WINDS DIMINISH WEDNESDAY NIGHT LIGHTER WINDS WILL RETURN AND FAVOR AN EAST TO SOUTHEAST DIRECTION INTO EARLY SATURDAY WITH A PERIOD OF MORE ONSHORE WINDS FRIDAY WITH A LIGHTER SYNOPTIC SCALE FLOW SUPPORTING LAKE BREEZE DEVELOPMENT. MDB && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
254 AM CDT SUN JUL 15 2012 .DISCUSSION... 837 PM CDT CONVECTIVE ACTIVITY HAS SETTLED THIS EVENING AND SHOULD BE DRY THROUGH THE REMAINDER OF THE EVENING. HAVE TWEAKED POPS TO REFLECT DIMINISHED CHANCES. LATE TONIGHT ANOTHER MID LEVEL DISTURBANCE IS EXPECTED TO DROP SOUTH ACROSS THE AREA. ISOLATED THUNDERSTORMS ASSOCIATED WITH THIS WAVE HAVE ALREADY DEVELOPED OVER PORTIONS OF WISCONSIN...BUT OVERALL FORCING/MOISTURE CONVERGENCE APPEARS TO BE VERY WEAK AND DO NOT EXPECT MORE THAN ISOLATED COVERAGE IF ANY AS IT MOVES INTO NORTHERN ILLINOIS. OTHERWISE...ONLY MADE MINOR TWEAKS TO HOURLY TRENDS FOR T/TD...OVERALL FORECAST APPEARS ON TRACK. BMD //PREV DISCUSSION... 210 PM CDT CONCERNS WITH THE FORECAST ARE CENTERED ON CONVECTION THROUGH THIS EVENING...AND THEN HOT TEMPERATURES THE NEXT SEVERAL DAYS. SHORT TERM...REST OF THIS AFTERNOON THROUGH SUNDAY... TOWERING CUMULUS ALONG WITH SOME SCATTERED STORMS HAVE DEVELOPED EARLY THIS AFTERNOON ACROSS MAINLY THE EASTERN HALF OF THE FORECAST AREA ALONG AND AHEAD OF A SHEARED OUT UPPER IMPULSE AND AN ELEVATED /850-700MB/ WIND AND MOISTURE CONVERGENCE ZONE. GIVEN A FAIRLY UNSTABLE AIR MASS PER MODIFIED AMDAR SOUNDINGS AND RAP ANALYSIS...WITH MLCAPE VALUES OF 1000 TO 1500 J/KG...THESE STORMS SHOULD CONTINUE TO REGENERATE WITH THE FURTHER FOCI OF BOUNDARY INTERACTIONS. HAVE ALREADY SEEN THE DIVERGENT VELOCITY SIGNATURES ON RADAR UNDERNEATH THESE STORMS WITHIN JUST TWO RADAR VCPS...SHOWING THE DOWNDRAFT POTENTIAL ONCE AGAIN. ENVIRONMENTAL DCAPE VALUES ANALYZED BY THE RAP OF 700 TO 1000 J/KG ARE SLIGHTLY LESS THAN YESTERDAY...BUT SUFFICIENT ENOUGH FOR A POSSIBLE ISOLATED SEVERE GUST...INCLUDING IN NEARSHORE AREAS OF THE LAKE IN ANY STORMS THAT DRIFT NORTHEAST OVER THAT AREA. AN UPPER LEVEL SHORT WAVE...AS PART OF THE LARGER BROAD TROUGH...IS MOVING SOUTHEAST ACROSS WESTERN WI EARLY THIS AFTERNOON. THE INITIAL SURFACE BOUNDARY UNDERNEATH THIS IS HELPING TO FOCUS SOME SCATTERED STORMS...WITH SIMILAR ML INSTABILITY OF 1000 TO 1500 J/KG. MORE DEVELOPMENT IS ANTICIPATED THROUGH EARLY EVENING IN ADVANCE OF THIS AS CONVERGENCE IMPROVES...AND SOME OF THIS MAY POTENTIALLY BE ALONG OUTFLOW THAT IS ALREADY INTO NORTHWEST IL. EXPLICIT CONVECTIVE MODELS DO KEY IN ON SCATTERED STORM DEVELOPMENT TOWARD THE I-39 CORRIDOR BY LATE AFTERNOON. WITH THE SHORT WAVE AND FRONTAL APPROACH...ALONG WITH DEEP LAYER SHEAR VALUES OF SEMI-DECENT 30 KT PROJECTED...THESE SHOWERS AND STORMS HAVE POTENTIAL TO HANG ON LATER INTO THE EVENING. THE COOL FRONT WILL MOVE THROUGH THE AREA LATE TONIGHT AND SUNDAY MORNING...BUT WASHING OUT AS IT DOES. TEMPERATURES ON SUNDAY ARE ACTUALLY EXPECTED TO BE SLIGHTLY HIGHER THAN TODAY...AND DEW POINTS SHOULD BE CLOSE. THIS WILL AGAIN PROVIDE MODEST INSTABILITY...BUT HEIGHT RISES ALOFT SHOULD TEMPER STORM DEVELOPMENT. A ROGUE LATE AFTERNOON CELL OR TWO CANNOT BE RULED OUT ALONG WEAK SURFACE CONVERGENCE...BUT HAVE NOT MENTIONED IN THE FORECAST AT THIS TIME. HIGHS ON SUNDAY LOOK TO TOP OUT IN THE LOWER TO MID 90S...WITH A LAKE BREEZE PROVIDING SOME COOLING FOR DOWNTOWN CHICAGO AND NEARBY AREAS DURING THE AFTERNOON. THESE LAKE SHORE AREAS STILL MAY REACH 90 OR NEAR IT BEFORE THE LAKE BREEZE PUSHES THROUGH. MTF LONG TERM...SUNDAY NIGHT THROUGH SATURDAY... THE UPPER LEVEL RIDGE REESTABLISHES ITSELF ACROSS THE CENTRAL US AS THE TROUGH MOVES OFF TOWARD THE NEW ENGLAND AREA. A WEAKENING AREA OF LOW PRESSURE MOVES NORTH OF THE GREAT LAKES MONDAY NIGHT...WHILE ITS COLD FRONT SINKS SOUTH DOWN THE LAKE ON TUESDAY. PRECIP CHANCES DIMINISH AS THE TROUGH DRIFTS EASTWARD SUNDAY NIGHT. THE BEST CHANCE OF PRECIP IN THE EXTENDED IS ALONG THE COLD FRONT LATE TUESDAY THROUGH WEDNESDAY. GUIDANCE DIFFERS ON THE SPEED OF THE FRONT...WITH THE GFS BRINGING THE FRONT THROUGH MUCH FASTER THAN THE ECMWF. GIVEN ISSUES WITH THE GFS LATELY...AND THE ECMWF HAVING VERY CONSISTENT TIMING OVER THE PAST FEW DAYS...GOING WITH THE SLOWER SOLUTION. BOTH MODELS INDICATE MOISTURE WILL POOL ALONG THE FRONT...BUT THEN DISSIPATE AS THE FRONT ENTERS NORTHERN IL. THEREFORE...KEPT BEST PRECIP CHANCES NORTH OF I-80. LIMITED ACTUAL PRECIP CHANCES TO LESS THAN 50 PERCENT GIVEN THE MODEL TRENDS AND DRY CONDITIONS. HIGH PRESSURE BUILDS IN BEHIND THE FRONT...AND GUIDANCE SUGGESTS RANDOM PERIODS OF PRECIP DURING THE LATTER HALF OF NEXT WEEK. HOWEVER...WITH NO CLEAR SOURCE OF FORCING...QUESTIONABLE MOISTURE SOURCES...AND DROUGHT CONDITIONS...DECIDED TO KEEP THE REMAINDER OF THE EXTENDED DRY. AT THIS POINT THE BIGGER CRIME IS GETTING FOLKS HOPES UP FOR RAIN ONLY TO DISAPPOINT. HEAT BUILDS ACROSS THE REGION THROUGH TUESDAY. GUIDANCE SUGGESTS THERE WILL ONLY BE A SMALL PUSH OF SLIGHTLY COOLER AIR BEHIND THE FRONT...WITH WEDNESDAY LOOKING TO BE A BIT COOLER. HOWEVER 850 HPA TEMPS BEGIN TO WARM ALMOST IMMEDIATELY WITH THE UPPER LEVEL RIDGE SW OF THE CWA. THEREFORE...THE LATTER HALF OF NEXT WEEK LOOKS ABOVE AVERAGE. JEE && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 06Z... * LIGHT SOUTH WIND BECOMING SOUTHWEST OVERNIGHT. * VERY LOW PROBABILITY SHRA/TSRA POTENTIAL LATER TONIGHT INTO EARLY MORNING. * WIND SHIFT FROM LIGHT WEST-SOUTHWEST TO EAST-NORTHEAST WITH WEAK TROUGH PASSAGE MID-LATE MORNING AND LAKE BREEZE PUSH FROM THE EAST THIS AFTERNOON. MDB //DISCUSSION...UPDATED 06Z... THE MAIN FORECAST CONCERNS ARE SLIM CHANCES FOR ISOLD SHRA/TSRA THROUGH DAYBREAK...AN OFF CHANCE THIS AFTERNOON...AND A LAKE BREEZE PUSHING INLAND DURING THE AFTERNOON. SATELLITE IMAGERY CONTINUES TO SHOW AN UPPER LEVEL TROUGH MOVING SOUTHEASTWARD ACROSS CENTRAL/SOUTHERN WISCONSIN EARLY TONIGHT. RADAR CONTINUES TO SHOW SOME SHRA/TSRA ACTIVITY AHEAD OF THIS WAVE ACROSS SOUTHERN WI BUT LATEST IMAGERY SHOWS A WEAKENING TREND TO THIS ACTIVITY. ENERGY ASSOCIATED WITH THE SHORTWAVE WILL REACH THE AREA IN THE NEXT 2-3 HOURS OR SO AND BRING A VERY LOW CHANCE FOR KICKING OFF SHRA/TSRA AS IT DOES SO. WILL CONTINUE TO LEAVE ANY PRECIP MENTION OUT OF THE TAFS WITH THE CHANCE FOR OCCURRENCE TOO LOW. SHOULD ANYTHING MAKE IT INTO NORTHERN ILLINOIS/NW INDIANA IT WOULD BE VERY ISOLATED. IN ADDITION...A WEAK SURFACE TROUGH WILL BE SETTLING ACROSS THE AREA LATER THIS MORNING. THIS MAY ALSO SERVE AS A FOCUS FOR SHRA/TSRA DEVELOPMENT DURING THE MID/LATE MORNING HOURS BUT THIS CHANCE IS ALSO VERY LOW. LIGHT WINDS FAVORING A SOUTHWESTERLY DIRECTION WILL TURN NORTHERLY AS THE SURFACE TROUGH PASSES MID/LATE MORNING. THE FLOW WILL REMAIN WEAK WHICH WILL SUPPORT THE DEVELOPMENT OF A LAKE BREEZE WHICH SHOULD MOVE FAIRLY FAR INLAND THIS AFTERNOON. WINDS WILL TURN EAST TO NORTHEAST AS THE LAKE BREEZE BOUNDARY PASSES. IT IS POSSIBLE THAT THE LAKE BREEZE COULD AID SOME SPOTTY TSRA DEVELOPMENT THIS AFTERNOON BUT WARMING OF THE MID LEVELS SHOULD PRECLUDE MUCH OF NOT ALL DEVELOPMENT THIS AFTERNOON. MDB //ORD AND MDW CONFIDENCE...UPDATED 06Z... * HIGH CONFIDENCE IN OVERALL WIND TRENDS. * MEDIUM-HIGH CONFIDENCE IN NO ADDITIONAL TSRA AT TERMINALS. * HIGH CONFIDENCE IN LAKE BREEZE OCCURRENCE THIS AFTERNOON. MDB //OUTLOOK FOR ORD/MDW FOR 12Z MONDAY-12Z SATURDAY...UPDATED 00Z... MONDAY...VFR. TUESDAY...VFR. CHANCE TSRA TUES NGT. WEDNESDAY...SLGT CHANCE TSRA. OTHERWISE VFR. THURSDAY AND FRIDAY...VFR. RATZER && .MARINE... 246 AM CDT A SERIES OF SYSTEMS WILL PASS NORTH OF LAKE MICHIGAN BETWEEN NOW AND WEDNESDAY...EACH BRINGING A COOL FRONTAL BOUNDARY DOWN THE LAKE. THE FIRST AREA OF LOW PRESSURE IS MOVING ACROSS EASTERN ONTARIO AND EXTENDS TOWARD NORTHERN LAKE MICHIGAN. A WEAK FRONT CONTINUES TO DROP SOUTHWARD DOWN THE LAKE AND WILL BE TO THE SOUTH BY LATE MORNING. HIGH PRESSURE THEN QUICKLY RETURNS BEHIND THE FRONT THIS AFTERNOON. WINDS WILL LIKELY BECOME LIGHT AND VARIABLE OR ONSHORE ACROSS MUCH OF THE CENTRAL AND SOUTHERN PART OF THE LAKE THIS AFTERNOON THEN BECOME SOUTHERLY ACROSS THE LAKE THIS EVENING. ANOTHER LOW PRESSURE SYSTEM TAKES SHAPE ACROSS THE DAKOTAS AND TURNS EASTWARD AND CROSSES LAKE SUPERIOR MONDAY EVENING. THIS LOW IS EXPECTED TO BE FAIRLY WELL ORGANIZED AND TIGHTENS THE PRESSURE GRADIENT ACROSS THE NORTHERN END OF THE LAKE LEADING TO A PERIOD OF 25-30 KT WINDS LATE MONDAY AFTERNOON AND MONDAY EVENING. AS THE LOW EXITS INTO SOUTHERN QUEBEC TUESDAY A COLD FRONT WILL MARCH DOWN THE LAKE BRINGING A SHIFT FROM BREEZY SOUTHERLY WINDS TO BREEZY NORTHWESTERLY WINDS. AT THIS POINT...SPEEDS ON THE BACK SIDE OF THE FRONT LOOK TO BE MODESTLY LOWER THAN THE WINDS AHEAD OF THE FRONT. WILL NEED TO WATCH FOR SMALL CRAFT ADVISORY CONDITIONS FROM WEDNESDAY AFTERNOON BUT AT THIS POINT IT SEEMS THAT CRITERIA WILL NOT BE MET...HOWEVER...THE LONG FETCH IN PLACE BEHIND THIS FRONT MAY ALLOW WAVES TO BUILD ENOUGH TO WARRANT ISSUANCE. HIGH PRESSURE THEN BUILDS IN WEDNESDAY NIGHT AND DRIFTS EASTWARD ACROSS MICHIGAN INTO FRIDAY NIGHT. ONCE THE STRONGER NORTH TO NORTHEAST WINDS DIMINISH WEDNESDAY NIGHT LIGHTER WINDS WILL RETURN AND FAVOR AN EAST TO SOUTHEAST DIRECTION INTO EARLY SATURDAY WITH A PERIOD OF MORE ONSHORE WINDS FRIDAY WITH A LIGHTER SYNOPTIC SCALE FLOW SUPPORTING LAKE BREEZE DEVELOPMENT. MDB && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1241 AM CDT SUN JUL 15 2012 .DISCUSSION... 837 PM CDT CONVECTIVE ACTIVITY HAS SETTLED THIS EVENING AND SHOULD BE DRY THROUGH THE REMAINDER OF THE EVENING. HAVE TWEAKED POPS TO REFLECT DIMINISHED CHANCES. LATE TONIGHT ANOTHER MID LEVEL DISTURBANCE IS EXPECTED TO DROP SOUTH ACROSS THE AREA. ISOLATED THUNDERSTORMS ASSOCIATED WITH THIS WAVE HAVE ALREADY DEVELOPED OVER PORTIONS OF WISCONSIN...BUT OVERALL FORCING/MOISTURE CONVERGENCE APPEARS TO BE VERY WEAK AND DO NOT EXPECT MORE THAN ISOLATED COVERAGE IF ANY AS IT MOVES INTO NORTHERN ILLINOIS. OTHERWISE...ONLY MADE MINOR TWEAKS TO HOURLY TRENDS FOR T/TD...OVERALL FORECAST APPEARS ON TRACK. BMD //PREV DISCUSSION... 210 PM CDT CONCERNS WITH THE FORECAST ARE CENTERED ON CONVECTION THROUGH THIS EVENING...AND THEN HOT TEMPERATURES THE NEXT SEVERAL DAYS. SHORT TERM...REST OF THIS AFTERNOON THROUGH SUNDAY... TOWERING CUMULUS ALONG WITH SOME SCATTERED STORMS HAVE DEVELOPED EARLY THIS AFTERNOON ACROSS MAINLY THE EASTERN HALF OF THE FORECAST AREA ALONG AND AHEAD OF A SHEARED OUT UPPER IMPULSE AND AN ELEVATED /850-700MB/ WIND AND MOISTURE CONVERGENCE ZONE. GIVEN A FAIRLY UNSTABLE AIR MASS PER MODIFIED AMDAR SOUNDINGS AND RAP ANALYSIS...WITH MLCAPE VALUES OF 1000 TO 1500 J/KG...THESE STORMS SHOULD CONTINUE TO REGENERATE WITH THE FURTHER FOCI OF BOUNDARY INTERACTIONS. HAVE ALREADY SEEN THE DIVERGENT VELOCITY SIGNATURES ON RADAR UNDERNEATH THESE STORMS WITHIN JUST TWO RADAR VCPS...SHOWING THE DOWNDRAFT POTENTIAL ONCE AGAIN. ENVIRONMENTAL DCAPE VALUES ANALYZED BY THE RAP OF 700 TO 1000 J/KG ARE SLIGHTLY LESS THAN YESTERDAY...BUT SUFFICIENT ENOUGH FOR A POSSIBLE ISOLATED SEVERE GUST...INCLUDING IN NEARSHORE AREAS OF THE LAKE IN ANY STORMS THAT DRIFT NORTHEAST OVER THAT AREA. AN UPPER LEVEL SHORT WAVE...AS PART OF THE LARGER BROAD TROUGH...IS MOVING SOUTHEAST ACROSS WESTERN WI EARLY THIS AFTERNOON. THE INITIAL SURFACE BOUNDARY UNDERNEATH THIS IS HELPING TO FOCUS SOME SCATTERED STORMS...WITH SIMILAR ML INSTABILITY OF 1000 TO 1500 J/KG. MORE DEVELOPMENT IS ANTICIPATED THROUGH EARLY EVENING IN ADVANCE OF THIS AS CONVERGENCE IMPROVES...AND SOME OF THIS MAY POTENTIALLY BE ALONG OUTFLOW THAT IS ALREADY INTO NORTHWEST IL. EXPLICIT CONVECTIVE MODELS DO KEY IN ON SCATTERED STORM DEVELOPMENT TOWARD THE I-39 CORRIDOR BY LATE AFTERNOON. WITH THE SHORT WAVE AND FRONTAL APPROACH...ALONG WITH DEEP LAYER SHEAR VALUES OF SEMI-DECENT 30 KT PROJECTED...THESE SHOWERS AND STORMS HAVE POTENTIAL TO HANG ON LATER INTO THE EVENING. THE COOL FRONT WILL MOVE THROUGH THE AREA LATE TONIGHT AND SUNDAY MORNING...BUT WASHING OUT AS IT DOES. TEMPERATURES ON SUNDAY ARE ACTUALLY EXPECTED TO BE SLIGHTLY HIGHER THAN TODAY...AND DEW POINTS SHOULD BE CLOSE. THIS WILL AGAIN PROVIDE MODEST INSTABILITY...BUT HEIGHT RISES ALOFT SHOULD TEMPER STORM DEVELOPMENT. A ROGUE LATE AFTERNOON CELL OR TWO CANNOT BE RULED OUT ALONG WEAK SURFACE CONVERGENCE...BUT HAVE NOT MENTIONED IN THE FORECAST AT THIS TIME. HIGHS ON SUNDAY LOOK TO TOP OUT IN THE LOWER TO MID 90S...WITH A LAKE BREEZE PROVIDING SOME COOLING FOR DOWNTOWN CHICAGO AND NEARBY AREAS DURING THE AFTERNOON. THESE LAKE SHORE AREAS STILL MAY REACH 90 OR NEAR IT BEFORE THE LAKE BREEZE PUSHES THROUGH. MTF LONG TERM...SUNDAY NIGHT THROUGH SATURDAY... THE UPPER LEVEL RIDGE REESTABLISHES ITSELF ACROSS THE CENTRAL US AS THE TROUGH MOVES OFF TOWARD THE NEW ENGLAND AREA. A WEAKENING AREA OF LOW PRESSURE MOVES NORTH OF THE GREAT LAKES MONDAY NIGHT...WHILE ITS COLD FRONT SINKS SOUTH DOWN THE LAKE ON TUESDAY. PRECIP CHANCES DIMINISH AS THE TROUGH DRIFTS EASTWARD SUNDAY NIGHT. THE BEST CHANCE OF PRECIP IN THE EXTENDED IS ALONG THE COLD FRONT LATE TUESDAY THROUGH WEDNESDAY. GUIDANCE DIFFERS ON THE SPEED OF THE FRONT...WITH THE GFS BRINGING THE FRONT THROUGH MUCH FASTER THAN THE ECMWF. GIVEN ISSUES WITH THE GFS LATELY...AND THE ECMWF HAVING VERY CONSISTENT TIMING OVER THE PAST FEW DAYS...GOING WITH THE SLOWER SOLUTION. BOTH MODELS INDICATE MOISTURE WILL POOL ALONG THE FRONT...BUT THEN DISSIPATE AS THE FRONT ENTERS NORTHERN IL. THEREFORE...KEPT BEST PRECIP CHANCES NORTH OF I-80. LIMITED ACTUAL PRECIP CHANCES TO LESS THAN 50 PERCENT GIVEN THE MODEL TRENDS AND DRY CONDITIONS. HIGH PRESSURE BUILDS IN BEHIND THE FRONT...AND GUIDANCE SUGGESTS RANDOM PERIODS OF PRECIP DURING THE LATTER HALF OF NEXT WEEK. HOWEVER...WITH NO CLEAR SOURCE OF FORCING...QUESTIONABLE MOISTURE SOURCES...AND DROUGHT CONDITIONS...DECIDED TO KEEP THE REMAINDER OF THE EXTENDED DRY. AT THIS POINT THE BIGGER CRIME IS GETTING FOLKS HOPES UP FOR RAIN ONLY TO DISAPPOINT. HEAT BUILDS ACROSS THE REGION THROUGH TUESDAY. GUIDANCE SUGGESTS THERE WILL ONLY BE A SMALL PUSH OF SLIGHTLY COOLER AIR BEHIND THE FRONT...WITH WEDNESDAY LOOKING TO BE A BIT COOLER. HOWEVER 850 HPA TEMPS BEGIN TO WARM ALMOST IMMEDIATELY WITH THE UPPER LEVEL RIDGE SW OF THE CWA. THEREFORE...THE LATTER HALF OF NEXT WEEK LOOKS ABOVE AVERAGE. JEE && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 06Z... * LIGHT SOUTH WIND BECOMING SOUTHWEST OVERNIGHT. * VERY LOW PROBABILITY SHRA/TSRA POTENTIAL LATER TONIGHT INTO EARLY MORNING. * WIND SHIFT FROM LIGHT WEST-SOUTHWEST TO EAST-NORTHEAST WITH WEAK TROUGH PASSAGE MID-LATE MORNING AND LAKE BREEZE PUSH FROM THE EAST THIS AFTERNOON. MDB //DISCUSSION...UPDATED 06Z... THE MAIN FORECAST CONCERNS ARE SLIM CHANCES FOR ISOLD SHRA/TSRA THROUGH DAYBREAK...AN OFF CHANCE THIS AFTERNOON...AND A LAKE BREEZE PUSHING INLAND DURING THE AFTERNOON. SATELLITE IMAGERY CONTINUES TO SHOW AN UPPER LEVEL TROUGH MOVING SOUTHEASTWARD ACROSS CENTRAL/SOUTHERN WISCONSIN EARLY TONIGHT. RADAR CONTINUES TO SHOW SOME SHRA/TSRA ACTIVITY AHEAD OF THIS WAVE ACROSS SOUTHERN WI BUT LATEST IMAGERY SHOWS A WEAKENING TREND TO THIS ACTIVITY. ENERGY ASSOCIATED WITH THE SHORTWAVE WILL REACH THE AREA IN THE NEXT 2-3 HOURS OR SO AND BRING A VERY LOW CHANCE FOR KICKING OFF SHRA/TSRA AS IT DOES SO. WILL CONTINUE TO LEAVE ANY PRECIP MENTION OUT OF THE TAFS WITH THE CHANCE FOR OCCURRENCE TOO LOW. SHOULD ANYTHING MAKE IT INTO NORTHERN ILLINOIS/NW INDIANA IT WOULD BE VERY ISOLATED. IN ADDITION...A WEAK SURFACE TROUGH WILL BE SETTLING ACROSS THE AREA LATER THIS MORNING. THIS MAY ALSO SERVE AS A FOCUS FOR SHRA/TSRA DEVELOPMENT DURING THE MID/LATE MORNING HOURS BUT THIS CHANCE IS ALSO VERY LOW. LIGHT WINDS FAVORING A SOUTHWESTERLY DIRECTION WILL TURN NORTHERLY AS THE SURFACE TROUGH PASSES MID/LATE MORNING. THE FLOW WILL REMAIN WEAK WHICH WILL SUPPORT THE DEVELOPMENT OF A LAKE BREEZE WHICH SHOULD MOVE FAIRLY FAR INLAND THIS AFTERNOON. WINDS WILL TURN EAST TO NORTHEAST AS THE LAKE BREEZE BOUNDARY PASSES. IT IS POSSIBLE THAT THE LAKE BREEZE COULD AID SOME SPOTTY TSRA DEVELOPMENT THIS AFTERNOON BUT WARMING OF THE MID LEVELS SHOULD PRECLUDE MUCH OF NOT ALL DEVELOPMENT THIS AFTERNOON. MDB //ORD AND MDW CONFIDENCE...UPDATED 06Z... * HIGH CONFIDENCE IN OVERALL WIND TRENDS. * MEDIUM-HIGH CONFIDENCE IN NO ADDITIONAL TSRA AT TERMINALS. * HIGH CONFIDENCE IN LAKE BREEZE OCCURRENCE THIS AFTERNOON. MDB //OUTLOOK FOR ORD/MDW FOR 12Z MONDAY-12Z SATURDAY...UPDATED 00Z... MONDAY...VFR. TUESDAY...VFR. CHANCE TSRA TUES NGT. WEDNESDAY...SLGT CHANCE TSRA. OTHERWISE VFR. THURSDAY AND FRIDAY...VFR. RATZER && .MARINE... 145 PM CDT LOW PRESSURE ACROSS LAKE SUPERIOR WILL CONTINUE TO MOVE EAST THROUGH SUNDAY. THIS WILL STEER A COOL FRONT ACROSS THE LAKE LATE TONIGHT. AHEAD OF THIS WILL BE SOME SCATTERED STORMS...SOME OF WHICH ARE LIKELY TO BE GUSTY BASED ON THE ENVIRONMENT. THESE WILL BE MOST FAVORED ACROSS THE SOUTHERN THIRD OF THE LAKE INCLUDING NEAR SHORE AREAS OF IL...IN...AND SOUTHWEST MI. WINDS BEHIND THE FRONT ON SUNDAY WILL BECOME LIGHT AND BEGIN TURNING BACK TO SOUTHERLY ALREADY BY AFTERNOON. SOUTHWEST WINDS WILL INCREASE ON MON...WITH OPEN WATER LOCATIONS ACROSS THE NORTH LIKELY REACHING 30 KT DURING MON NIGHT. A COOL FRONT WILL SLOWLY WORK SOUTH ACROSS THE LAKE ON TUESDAY AND TUESDAY NIGHT. THIS WILL SHIFT WINDS TO THE NORTH AND PROVIDE A FOCUS FOR SCATTERED THUNDERSTORMS ONCE AGAIN. MTF && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1120 PM CDT SAT JUL 14 2012 .DISCUSSION... ISSUED 825 PM CDT SAT JUL 14 2012 CONVECTION CONTINUES TO DISSIPATE EARLY THIS EVENING WITH SEVERAL LOCATIONS RECEIVING SOME DECENT RAINFALL FOR A CHANGE. PEORIA... BLOOMINGTON AND THE NWS AT LINCOLN RECEIVED OVER 1 INCH OF RAIN. SOME GUSTY WINDS AND SMALL HAIL WERE ASSOCIATED WITH THE STRONGEST UPDRAFTS...BUT THOSE WERE FEW AND FAR BETWEEN. LATEST SATELLITE DATA INDICATES THE 500 MB TROF AXIS RIGHT OVER THE FORECAST AREA EARLY THIS EVENING. THERE WAS ANOTHER WEAK SHORTWAVE SEEN OVER NW IL AND THAT WAS DRIFTING ESE AND MAY KEEP AT LEAST ISOLATED SHOWERS GOING INTO THE OVERNIGHT HOURS. AREAS THAT DID RECEIVE THE RAINFALL TODAY WILL SEE SOME FOG DEVELOP LATER TONIGHT. CURRENT ZONE FORECAST HAS A GOOD HANDLE ON THE TRENDS THIS EVENING SO OTHER THAN THE USUAL TWEAKS WITH THE HOURLY TEMPS...NO OTHER CHANGES WERE MADE. AS A RESULT...NO ZONE UPDATE WILL BE NEEDED EARLY THIS EVENING. && .AVIATION... ISSUED 1115 PM CDT SAT JUL 14 2012 FOG DEVELOPMENT AND COVERAGE DURING THE EARLY MORNING HOURS THE MAIN FORECAST CONCERN. ALL THE STORMS HAVE DISSIPATED LEAVING MAINLY CLEAR SKIES AND LIGHT WINDS WHICH SHOULD LEAD TO FOG DEVELOPMENT...ESPECIALLY IN THE AREAS THAT RECEIVED THE RAIN OVER THE PAST 24 HOURS. THAT WOULD INCLUDE PIA...BMI AND CMI. DECATUR DID RECEIVE SOME VERY LIGHT AMOUNTS SO WILL INCLUDE SOME BRIEF MVFR VSBYS STARTING AT 09Z. FURTHER NORTH...MVFR AND POSSIBLY SOME BRIEF IFR VSBYS STARTING AT 09Z. WHAT FOG WE DO SEE OVERNIGHT SHOULD QUICKLY DISSPATE SUNDAY MORNING BY 13 OR 14Z FOLLOWED BY A RAPID INCREASE IN CUMULUS AFTR 16Z. FORECAST SOUNDINGS SUGGEST THERE SHOULD BE ENOUGH DRY AIR MIX DOWN TO KEEP CLOUDS SCATTERED BUT THAT WILL HAVE TO BE WATCHED...ESPECIALLY AT BMI AND CMI. CLOUD BASES WILL RANGE FROM 4000-5000 FEET BY LATE MORNING WITH THE CUMULUS FIELD DISSIPATING QUICKLY BY 00Z. SFC WINDS WILL BE LIGHT SOUTHERLY TONIGHT AND SSW AT 10 KTS OR LESS ON SUNDAY/SUNDAY EVENING. SMITH && .PREV DISCUSSION... ISSUED 236 PM CDT SAT JUL 14 2012 SCATTERED SHOWERS ACROSS CENTRAL ILLINOIS CONTINUE...WITH VERY LITTLE MOVEMENT UNDER A WEAK UPPER LEVEL TROF. CONVECTIVE ACTIVITY TO THE NW THIS MORNING SHOWING UP AS A LITTLE WEAK VORTEX ON VIS SAT IMAGERY THIS AFTERNOON. BECAUSE OF THAT...HAVE MADE A COUPLE OF CHANGES TO THE POPS FOR THE OVERNIGHT. OTHER THAN THAT...FORECAST IS MOSTLY DRY BEYOND TONIGHT. NEXT CHANCE FOR PRECIP COMES MID WEEK NEXT WEEK. ECMWF NOW HAVING SIMILAR ISSUE TO THE LAST FEW RUNS OF THE GFS...SO KEEP SCALING BACK THE EXTENDED POPS SHORT TERM...TONIGHT AND TOMORROW... FIRST CONCERN IS THE SMALL VORTEX TO THE NW MOVING NEAR THE REGION IN THE OVERNIGHT. NEITHER HRRR NOR THE 4KM WRF ARE PICKING UP ON THE SYSTEM...BUT THE AVAILABLE MOISTURE HAS NOW BEEN A BIT ALTERED... PARTICULARLY IN THE EASTERN HALF OF THE CWA. FEEL LESS LIKE THE SHOWERS AFTER 00Z WILL BE LIMITED TO REMNANTS FROM TODAY...AND HAVE EXPANDED THE CHANCE POPS TO COVER THE ENTIRE OVERNIGHT. IN ANY SPOTS THAT CLEAR OUT IN THE OVERNIGHT...PARTICULARLY IN THE EAST WHERE THE BOUNDARY LAYER MOISTURE HAS BEEN SIGNIF INCREASED BY THE SHOWERS AND THUNDERSTORMS THIS AFTERNOON...PATCHY FOG WILL BE POSSIBLE IN THE EARLY MORNING...AND HAVE PLACED THE MENTION IN THE GRIDS FOR A COUPLE HOURS... MAINLY EAST OF I-55. TOMORROW...IN THE WAKE OF EXITING SHOWERS...SOME SMALL POPS MOSTLY SOUTH OF INTERSTATE 70. THESE POPS ARE MOSTLY A PRODUCT OF PREVIOUS MODEL SOLUTIONS WITH THE ACTIVITY IN THE OHIO RIVER VALLEY. WILL KEEP THEM IN FOR ANY LINGERING OVERNIGHT PRECIP...BUT MOSTLY REFLECTIVE OF EARLY IN THE DAY. LONG TERM...MONDAY THROUGH FRIDAY... SCATTERED PRECIP THIS AFTERNOON WILL DO LITTLE TO ALLEVIATE THE DROUGHT OVER THE REGION... PARTICULARLY WITH THE RIDGE BUILDING IN THE WESTERN CONUS YET AGAIN...AND PUSHING 850MB TEMPS UP AND SFC TEMPS BACK INTO THE MID-UPPER 90S. DRY WEATHER CONTINUES...HAVE RAISED MAX TEMPS A DEGREE OR TWO OVER GUIDANCE SINCE MODELS KEEP PRECIP AND CLOUD COVER IN ABSENCE OF REAL MOISTURE. BEST CHANCES FOR PRECIP IN EXTENDED COME WITH WED NIGHT AND A PASSING TROF/SFC BOUNDARY AS AN UPPER WAVE RIPPLES THROUGH THE 500MB FLOW ALONG THE US/CAN BORDER. THIS FAR SOUTH...AVAILABLE MOISTURE WILL BE QUESTIONABLE...AS WILL THE AMOUNT OF SFC CONVERGENCE. HAVE PULLED BACK THE BLENDED POPS WHEREVER POSSIBLE. SCT SHOWER ACTIVITY IS ALL THAT IS LIKELY IN THIS FORECAST...A VERY SMALL PERCENTAGE OF AREA WILL SEE THE PRECIP. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
147 AM EDT SUN JUL 15 2012 .AVIATION.../06Z TAFS/ LIGHT SW FLOW OVER THE AREA THIS MORNING WITH MOIST AIRMASS IN PLACE. THIS MAY ALLOW SOME MVFR VSBYS IN BR TO DVLP OVERNIGHT. REMAINDER OF THE FCST SHOULD SEE VFR CONDITIONS. CONSIDERABLE DIURNAL CU EXPECTED TODAY... ESPECIALLY AT FWA. MODERATE INSTABILITY SHOULD DEVELOP ONCE AGAIN BUT WK FORCING ASSOCIATED WITH SHRTWV MOVG ACROSS THE GRTLKS SUGGESTS LITTLE CHC OF TSTMS AT THE TERMINALS. SKIES EXPECTED TO CLEAR THIS EVENING AND WINDS DIMINISH AS A RIDGE OF HIGH PRESSURE MOVES INTO THE AREA. && .PREV DISCUSSION... /ISSUED 311 PM EDT SAT JUL 14 2012/ SHORT TERM... OTHER THAN BAND OF ISOLD CONVN FORMING ALG NRN EDGE OF SUB-TROPICAL MSTR PLUME THIS AFTN...ATTN FOCUSED ON SLW EWD PROGRESSION OF MCV OVR NE IL EMBEDDED WITHIN LARGER SCALE TROUGHING ANCHORED BY POTENT SW SEEN IN VAPOR OVR NE MN. TAIL END OF IL MCV ACTIVELY CONVG THROUGH E/NE IL ATTM WITHIN AXIS OF STG SFC BASED HEATING/DESTABILIZATION. SHRT TERM RUC SOLUTIONS CARRY ORGANIZING CLUSTER FM KMDW - S OF KIKK E/NEWD THROUGH NWRN CWA LT THIS AFTN/EVE AND HAVE GENERALLY BOUGHT INTO ITS SOLUTION...DROPPING POP/WX MENTION AFT 03Z. OTHERWISE NRN STREAM SW TROUGH AND ASSOCD SFC TROUGH WILL BUCK EWD THIS PD W/UNFVRBL TIMING SUN AFTN AND PER GENERAL WKNG OF UPR TROUGH AND POORLY ALIGNED LL FLW SWD THROUGH THE OH VALLEY...MEASURABLE PCPN CHCS APPEAR SLIM AND FIT IN CONTEXT OF HIGHRES INDICATIONS OF AT BEST ISOLD AFTN DVLPMNT OVR FAR ERN/SERN AREAS. THUS PER THE PREPONDERANCE OF MODEL BASED GUIDANCE WILL CHOP CONSIDERABLY AND CONFINED TO SUN AFTN PD ALONE. TEMPS CONTD WELL ABV NORMAL THROUGH THE PD. LONG TERM...MONDAY THROUGH SATURDAY MID LEVEL HEIGHTS TO BUILD ACROSS THE SOUTHERN GREAT LAKES REGION ON MONDAY AS VORT FILAMENT CONTINUES TO GET ELONGATED AND WEAKEN FROM NEW ENGLAND INTO THE MID MS RIVER VALLEY. MEANWHILE...UPPER LOW WHICH HAS BEEN DIVORCED FROM MAIN WESTERLIES ACROSS THE PACIFIC NORTHWEST WILL EVENTUALLY GET ABSORBED BY A STRONGER PV ANOMALY DROPPING SOUTHWARD ACROSS BC CANADA. SEVERAL WEAK DISTURBANCES WILL EJECT EASTWARD FROM THIS PV ANOMALY ACROSS FAR SOUTHERN CANADA/GREAT LAKES REGION INTO TUESDAY...THROUGH THE BASE OF HUDSON BAY UPPER LEVEL TROUGH. THIS WILL EVENTUALLY ALLOW A COOL FRONT TO DROP SOUTHWARD ACROSS THE SOUTHERN GREAT LAKES TUESDAY NIGHT INTO WEDNESDAY. IN THE MEANTIME...STRONGER WEST/SOUTHWEST LOW LEVEL FLOW BETWEEN LOW LEVEL TROUGHING TO THE NORTHWEST AND SOUTHEAST CONUS ANTICYCLONE. THIS WILL ALLOW A WEST TO EAST ORIENTED LOW LEVEL THERMAL RIDGE TO ADVECT EASTWARD IN ADVANCE OF THE COOL FRONT MONDAY/TUESDAY. MORE FAVORABLE LOW LEVEL THERMAL RIDGE POSITIONING ON TUESDAY SHOULD MAKE THIS THE HOTTEST DAY OF THE PERIOD...ALTHOUGH WILDCARD WILL BE POTENTIAL OF SOME CIRRUS BLOWOFF FROM UPSTREAM CONVECTION. COMPLICATING THE TEMPERATURE FORECAST THIS PERIOD ARE LARGE DIFFERENCES IN GUIDANCE THERMODYNAMIC PROFILES. 12Z NAM SUGGESTS MIXING UP TO ABOUT 725 HPA TUESDAY AFTERNOON WHILE GFS IS MOISTER AND MUCH MORE SHALLOW WITH MIXING. HAVE GENERALLY DISCOUNTED GFS IDEA WITH MOIST LOW LEVEL BIAS AS OF LATE...WITH MORE WEIGHT TO THE DEEPER MIXED NAM...ALTHOUGH THIS SOLUTION MAY BE TOO WELL MIXED. THIS LARGELY SUPPORTS GOING HIGHS IN THE MID TO UPPER 90S AND HAVE SLIGHTLY ADJUSTED PREVIOUS FORECAST UPWARD...ALTHOUGH POTENTIAL AFOREMENTIONED HIGH CLOUD ISSUES WILL NEED TO BE CONSIDERED. MAY NEED TO CONSIDER HEAT HEADLINES EVENTUALLY FOR TUESDAY WITH HEAT INDICES AROUND 100 EXPECTED. NO SIGNIFICANT CHANGES MADE TO LOW CHANCE TSRA POPS LATE TUESDAY NIGHT ACROSS THE NORTH...EXPANDING ACROSS REMAINDER OF FORECAST AREA WEDNESDAY WITH THE FRONT. LIMITING FACTORS FOR ORGANIZED CONVECTION ARE MORE SUBSTANTIAL SHEAR PROFILES WELL BEHIND THE FRONT...LIMITED MID LEVEL LAPSE RATES...AND STRONGER UPPER FORCING TRACKING ACROSS THE NORTHERN GREAT LAKES. COOLER CONDITIONS FOR THURSDAY AND FRIDAY BEHIND THE FRONT...ALTHOUGH IT APPEARS HEAT WILL RETURN AS UPPER RIDGING BUILDS BACK INTO THE AREA JUST BEYOND THIS FORECAST PERIOD. LOCAL AREA COULD BE PRONE TO CONVECTIVE CHANCES IN ADVANCE OF THIS BUILDING RIDGE TOWARD THE END OF THE PERIOD...BUT CONFIDENCE MUCH TO LOW TO INCLUDE IN ONGOING VERY DRY PATTERN. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ SHORT TERM...T LONG TERM...MARSILI AVIATION...JT
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1217 AM CDT SUN JUL 15 2012 ...UPDATED SYNOPSIS AND AVIATION DISCUSSION... .SYNOPSIS... ISSUED AT 1209 AM CDT SUN JUL 15 2012 AT 00Z SUNDAY A 500MB HIGH WAS CENTERED OVER SOUTHEAST COLORADO AND NORTHEAST NEW MEXICO AND AN UPPER LEVEL RIDGE AXIS EXTENDED NORTH NORTHEAST INTO NORTH DAKOTA. AN UPPER LEVEL TROUGH WAS POSITIONED ACROSS THE NORTHWESTERN UNITED STATES AND A WEAK ANTICYCLONIC FLOW APPEARS TO BE LOCATED ACROSS EASTERN NEW MEXICO. A 70KT UPPER LEVEL JET WAS LOCATED WEST OF A 500MB HIGH AND EXTENDED FROM SOUTHWEST WYOMING INTO SOUTHEAST CALIFORNIA. ANOTHER JET STREAK WAS LOCATED BETWEEN THE DEVELOPING EAST TEXAS UPPER LOW AND THE SOUTHEAST COLORADO UPPER HIGH. THE NOSE OF THIS UPPER JET WAS LOCATED NEAR SOUTH CENTRAL KANSAS AND NORTHWEST OKLAHOMA. A 700MB HIGH EXTENDED FROM THE PANHANDLE OF OKLAHOMA ACROSS WESTERN KANSAS WITH TEMPERATURES RANGING FROM +12C AT DODGE CITY, AMARILLO, AND NORTH PLATTE TO +17C AT DENVER. AN AREA OF HIGHER DEWPOINTS WERE ALSO PRESENT ALONG AND EAST OF THE 12C ISOTHERM. 850MB TEMPERATURES ACROSS WESTERN KANSAS AT 00Z SUNDAY WERE 1-2C WARMER WHEN COMPARED TO 00Z SATURDAY TEMPERATURES BUT SOME COOLING (1-2C) WAS OBSERVED AT OKLAHOMA CITY AND SPRINGFIELD. && .SHORT TERM...(THIS EVENING THROUGH TOMORROW) ISSUED AT 304 PM CDT SAT JUL 14 2012 A RIDGE OF UPPER LEVEL HIGH PRESSURE WILL DOMINATE THE HIGH PLAINS FROM NEW MEXICO INTO WESTERN KANSAS AND NEBRASKA INTO SUNDAY. A LEE TROUGH OF LOW PRESSURE WILL ALSO REMAIN IN EASTERN COLORADO WITH LIGHT SOUTH TO SOUTHEAST WINDS TONIGHT. THE PRESSURE GRADIENT THEN TIGHTENS ON SUNDAY WITH SOUTH TO SOUTHWEST WINDS OF 15 TO 25 MPH AND GUSTY. A MID LEVEL CAPPING INVERSION WILL ALSO CONTINUE INTO SUNDAY AFTERNOON, AND WITH TEMPERATURES APPROACHING 100, THE CAP MAY WEAKEN ENOUGH TO SUPPORT SOME HIGH BASED THUNDERSTORMS LATE THIS AFTERNOON INTO EARLY EVENING AND AGAIN ON SUNDAY. WILL ADD A SLIGHT CHANCE OF THUNDER MAINLY EAST OF A LINE FROM WAKEENEY TO MEADE. WITH DEWPOINTS ALSO MIXING OUT, IF ANY THUNDERSTORMS FORM, THEY COULD PUT OUT SOME LOCALLY STRONG GUSTS FROM 40 TO 50 MPH. THE HRRR MESOSCALE MODEL ALSO SUPPORTS A FEW THUNDERSTORMS LATE THIS AFTERNOON AND EARLY EVENING. OVERNIGHT LOWS WILL BE MILD AND IN THE MID TO UPPER 60S UNDER MOSTLY CLEAR SKIES. FOR SUNDAY EXPECT HIGHS NEAR THE CENTURY MARK WITH MOSTLY CLEAR TO PARTLY CLOUDY SKIES. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 435 PM CDT SAT JUL 14 2012 THERE WERE LITTLE OVERALL CHANGES IN EXPECTATIONS NOTED FOR THE EXTENDED FORECAST PERIOD. THE GENERAL PATTERN CONTINUES TO INDICATE A WEAKLY POSITIVE TILTED UPPER RIDGE BUILDING INTO THE GREAT PLAINS. THE RIDGE BECOMES SLOWLY FLATTENED WITH TIME AS SHORTWAVES RIDE THE NORTHERN PERIPHERY OF THIS RIDGE THROUGH THE WEEK. THIS WARM AIRMASS WILL BE MARKED BY WARM TEMPERATURES IN THE MID TO UPPER 90S, AND TEMPERATURES AROUND 100 DEGREES BY MID TO LATE WEEK. CAPPING IS WEAK, ESPECIALLY ACROSS CENTRAL KANSAS WHERE 700 MB TEMPERATURES ARE UNDER 10 DEGREES C. AN ISOLATED BRIEF AIRMASS THUNDERSTORM CANNOT BE COMPLETELY RULED OUT ANY DAY, BUT CHANCES ARE QUITE LOW GIVEN THE LACK OF NOTED SURFACE CONVERGENCE. THE BEST CHANCES MIGHT BE FARTHER WEST AND SOUTH ON THE HIGHER TERRAIN OF THE PANHANDLES AND EASTERN COLORADO. SOUTHWEST KANSAS SHOULD REMAIN IN A WARM SECTOR THROUGH HE ENTIRE PERIOD, WHILE A STATIONARY FRONT RUNNING FROM IOWA THROUGH NEBRASKA AND SOUTH DAKOTA SHOULD BE A FOCUS FOR MESOSCALE CONVECTIVE SYSTEMS EACH NIGHT THROUGH THE MID TO LATE WEEK, AND REMAIN FOCUSED WELL AWAY FROM CENTRAL KANSAS. CONVECTIVE STORMS THAT DEVELOP FARTHER WEST WILL HAVE POOR STEERING FLOW WITH SUCH LIGHT MEAN WINDS DUE TO THE UPPER HIGH. THE ATMOSPHERE WILL PROBABLY BE MORE CONDUCIVE TO HEAT BURSTS AND GUSTY WINDS THAN TO SEVERE THUNDERSTORMS, ESPECIALLY WEST OF HIGHWAY 283 TO THE COLORADO LINE. TEMPERATURES BY LATE IN THE WEEK WERE RAISED A FEW DEGREES. SOME OF THE BIAS CORRECTED MODEL OUTPUT STATISTICS GUIDANCE IS SUPPORTIVE OF WARMER HIGHS UNDER THE UPPER RIDGE BY FRIDAY AND SATURDAY. WIDESPREAD TEMPERATURES IN EXCESS OF 100 DEGREES AND POSSIBLY TO AROUND 105 ARE INDICATED BY THIS GUIDANCE, AND SEEMS QUITE REASONABLE. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 1209 AM CDT SUN JUL 15 2012 SURFACE PRESSURE GRADIENT ACROSS WESTERN KANSAS WILL STRENGTHEN TODAY AS SURFACE PRESSURES FALL ALONG WITH LEE OF THE ROCKIES. SURFACE LEE TROUGH WILL STAY WEST OF WESTERN KANSAS TODAY SO SOUTH/SOUTHEAST WINDS WILL PERSIST AS WIND SPEEDS INCREASE INTO THE 15 TO 20KT RANGE BY THE EARLY AFTERNOON. BUFR SOUNDINGS KEEP A LAYER OF MOISTURE IN THE 700-600MB LEVEL ALONG WITH SOME WEAK MID LEVEL INSTABILITY SO SOME HIGH BASED (VFR) CLOUDS ARE EXPECTED LATER THIS MORNING/AFTERNOON. && .PRELIMINARY POINT TEMPS/POPS... DDC 72 97 72 98 / 0 10 10 10 GCK 70 98 72 97 / 0 0 10 10 EHA 68 99 70 95 / 10 10 10 10 LBL 70 99 72 97 / 0 10 10 10 HYS 71 98 74 99 / 0 10 10 10 P28 72 96 75 99 / 0 0 10 10 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...BURGERT SHORT TERM...KRUSE LONG TERM...RUSSELL AVIATION...BURGERT
AREA FORECAST DISCUSSION
NWS JACKSON KY
123 AM EDT SUN JUL 15 2012 .UPDATE... ISSUED AT 1100 PM EDT SAT JUL 14 2012 CONVECTION HAS DISSIPATED WITH THE LOSS OF DAYTIME HEATING. OVERNIGHT... A LULL IN THE ACTIVITY IS EXPECTED...BUT 21Z SREF AND 0Z NAM SHOW CONVECTIVE DEVELOPMENT GENERALLY OVER WESTERN SECTIONS TOWARD DAWN IN ADVANCE OF AN APPROACHING SHORTWAVE. THE 18Z GFS IS RELATIVELY CONSISTENT WITH THIS IDEA AS WELL. THEREFORE WE HAVE CONTINUED WITH A LULL IN POPS OVER THE NEXT COUPLE OF HOURS AND THEN HAVE THEM INCREASING INTO THE ISOLATED TO SCATTERED RANGE LATE. SOME SLIGHT ADJUSTMENTS TO HOURLY TEMPS AND DEWPOINTS WERE ALSO MADE. UPDATED GRIDS AND ZFP ARE ALREADY OUT. UPDATE ISSUED AT 815 PM EDT SAT JUL 14 2012 CONVECTION CONTINUES TO WEAKEN AS WE APPROACH SUNSET...AND OVERALL INTENSITIES HAVE DIMINISHED OVER THE PAST HOUR OR SO. MEASURABLE RAIN CHANCES WILL BE HIGHEST INITIALLY FROM NEAR JKL TOWARD THE BIG SANDY REGION AS THE REMAINING CONVECTION WORKS EAST NORTHEAST AND GRADUALLY IS EXPECTED TO CONTINUE TO WEAKEN OVER THE NEXT TWO HOURS. POPS AND SKY WERE UPDATED ACCORDINGLY BASED ON THESE TRENDS. && .SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT) ISSUED AT 335 PM EDT SAT JUL 14 2012 19Z SFC ANALYSIS SHOWS A WEAK PRESSURE PATTERN THROUGHOUT EAST KENTUCKY WITH NO CLEAR SYNOPTIC SCALE FEATURES TO KEY IN ON. HOWEVER...GIVEN THE HIGH PW AIR IN PLACE...NO CAP...AND SOME UPPER LEVEL ENERGY...NOT MUCH WAS NEEDED TO INITIATE THE STORMS LATE THIS MORNING THAT CONTINUE TO PERCOLATE OVER THE CWA AT THIS HOUR. THE CLOUDS FILLED IN FROM THE SOUTH BY MID MORNING AND CONVECTION FOLLOWED SHORTLY THEREAFTER. A FEW OF THE CELLS HAVE GOTTEN STRONG AND OTHERS HAVE MERGED/TRAINED OVER THE SAME SPOTS CREATING A CONCERN FOR MINOR URBAN OR SMALL STREAM FLOODING. REGARDLESS...THE RAINS IN MANY LOCATIONS ARE NOW PUTTING A SERIOUS DENT IN THEIR ANNUAL RAINFALL DEFICIT THANKS TO THESE PAST FEW DAYS. TEMPERATURES THIS AFTERNOON HAVE BEEN HIGHLY DEPENDENT ON THE CONVECTIVE PATTERN AND BREAKS FOR SUNSHINE WITH READINGS CURRENTLY RANGING FROM THE LOW 70S IN THE RAIN COOLED SOUTHERN I-75 CORRIDOR TO MID 80S JUST SOUTH OF STORMS NEAR I-64 AND IN THE...THUS FAR RAIN FREE...FAR SOUTHEAST. DEWPOINTS...MEANWHILE...REMAIN PEGGED IN THE LOW TO MID 70S SUPPLYING ALL THE JUICE THE CONVECTION COULD NEED. THE MODELS REMAIN IN AGREEMENT THAT EAST KENTUCKY WILL BE ON THE FRINGE OF THE WESTERN EXTENT OF A WEAK BERMUDA RIDGE AND AHEAD OF TROUGHING COMING FROM THE NORTHERN PLAINS AND CROSSING THE GREAT LAKES ON SUNDAY. THE ENERGY FROM THIS TROUGH WILL PASS BY TO THE NORTH LATER SUNDAY AND THIS WILL SERVE TO FURTHER LIMIT THE EFFECT OF THE EASTERN RIDGE ON OUR WEATHER INTO THE START OF THE NEW WORK WEEK. IN THIS ENVIRONMENT THE MESOSCALE...OR SMALLER...WILL DOMINATE SO HAVE LEANED MOST HEAVILY ON THE DETAILS OF THE NAM12 WITH A HEALTHY DOSE OF THE HRRR EARLY ON TONIGHT. SENSIBLE WEATHER WILL FEATURE SHOWERS AND THUNDERSTORMS WINDING DOWN...FOR THE MOST PART...AFTER SUNSET...BUT NOT BEFORE LEAVING BEHIND A FAIR AMOUNT OF RAINFALL IN SEVERAL LOCATIONS. EXPECT A LULL THROUGH THE MIDDLE OF THE NIGHT WITH PATCHY FOG A GOOD BET. THE APPROACH OF A SHORTWAVE INTO THE OHIO VALLEY LATE TONIGHT GIVES SOME CREDENCE TO THE NAM12/S IDEA OF A CONVECTIVE CLUSTER FORMING OVER CENTRAL TENNESSEE AND DRIFTING INTO THE CUMBERLAND VALLEY BY DAWN. SOME SUPPORT FROM THE GFS BOLSTERS THIS IDEA...AS WELL. ACCORDINGLY... HAVE DEVIATED FROM A STRICTLY DIURNALLY DRIVEN POP AND WX PATTERN TO ALLOW FOR THIS IDEA IN THE GRIDS...THOUGH NOT WHOLE HOG JUST YET. OTHERWISE...EXPECT A NEAR REPEAT OF TODAY FOR SUNDAY WITH CONVECTION DRIVEN MAINLY BY DIURNAL HEATING AND MINOR OUTFLOWS/DIFFERENTIAL HEATING BOUNDARIES. FOR BOTH TONIGHT AND SUNDAY NIGHT HAVE BEEN GENEROUS WITH THE PATCHY FOG IN THE GRIDS AFTER MIDNIGHT...BUT HELD OFF ON ANY DENSE UNTIL IT BECOMES MORE APPARENT WHERE THE BEST NOCTURNAL CLEARING WILL OCCUR. FOR TEMPERATURES...FOLLOWED A BLEND OF THE INHERITED GRIDS... PERSISTENCE...AND SOME OF THE LATEST MET VALUES...AGAIN NOT MUCH IN THE WAY OF TERRAIN EFFECTS FOR LOWS GIVEN THE HIGH DEWPOINTS. AS FOR POPS...HAVE ENDED UP SIMILAR TO A BLEND OF THE MET AND MAV MOS THROUGHOUT THE PERIOD. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 340 PM EDT SAT JUL 14 2012 THE MODELS REMAIN IN VERY GOOD AGREEMENT WITH THE GENERAL LONG WAVE PATTERN THROUGH THE EXTENDED. A SHORT WAVE TROUGH WILL BE EXITING THE APPALACHIANS ON MONDAY...HELPING TO TEMPORARILY BUCKLE RIDGING ACROSS THE PLAINS AND INTO THE MISSISSIPPI VALLEY THROUGH TUESDAY. THE RIDGE WILL THEN BUILD BACK IN STRONGER ACROSS THE PLAINS...WITH A MORE VIGOROUS SHORT WAVE TROUGH TO MOVE THROUGH THE GREAT LAKES AND NEW ENGLAND FOR WEDNESDAY AND THURSDAY...SENDING A COLD FRONT SOUTH ACROSS THE OHIO VALLEY. THE MODELS HAVE COME ON BOARD A BIT MORE...WITH A MORE PROGRESSIVE SOLUTION FOR THESE FEATURES. FOR EASTERN KENTUCKY...THIS WILL KEEP THE THREAT OF SCATTERED...MAINLY DIURNALLY DRIVEN CONVECTION ACROSS MOST OF THE AREA THROUGH FRIDAY...BEFORE DEEPER MOISTURE SINKS FAR ENOUGH SOUTH ON SATURDAY...TO ONLY JUSTIFY A FEW POPS UP ALONG THE TN/VA BORDER. TEMPERATURES CONTINUE TO LOOK SLIGHTLY ABOVE NORMAL...WITH PERSISTENT HUMIDITY UNTIL NEXT WEEKEND. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 123 AM EDT SUN JUL 15 2012 FOG AGAIN WILL BE THE FORECAST CHALLENGE THROUGH THE FIRST 6 HRS OF THE PERIOD. VFR CONDITIONS ARE PRESENT AT ALL TAF SITES AT ISSUANCE BUT CIGS ARE GRADUALLY THINNING AND THIS SHOULD ALLOW FOR ANOTHER ROUND OF LOW STRATUS BUILDING DOWN INTO THE VALLEYS TOWARDS DAYBREAK...WITH IFR OR WORSE DEVELOPING ON THE RIDGES WITHIN THE FIRST COUPLE OF HOURS OF THE PERIOD BEFORE AFFECTING THE LOWER ELEVATIONS BETWEEN 10Z AND 12Z. NEAR TERM MODELS SHOW PRECIP DEVELOPING OVER TN BEFORE MOVING INTO CENTRAL KY AROUND 12Z AND HAVE INCLUDED VC GROUPS TO ADDRESS THIS. SCATTERED TO NUMEROUS TSTMS ARE EXPECTED TO DEVELOP THIS AFTERNOON AND WILL ONCE AGAIN BRING TEMPORARY...LOCALIZED IFR OR WORSE TO ANY TERMINAL THAT SEES CONVECTION TODAY. HOWEVER...WITH LOW CONFIDENCE IN TIMING AND EXACT PLACEMENT OF CONVECTION...WILL CONTINUE WITH VC GROUPS FOR NOW AND LET THE 12Z ISSUANCE TAKE A BETTER LOOK AT THIS. LOW LEVEL WINDS ARE EXPECTED TO REDEVELOP AFTER 12Z OUT OF THE SW TO AROUND 5 TO 10 KTS AND CONTINUE THROUGH THE EVENING BEFORE DIMINISHING WITH CONVECTION AFTER SUNSET. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JP SHORT TERM...GREIF LONG TERM....GEOGERIAN AVIATION...MB
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
430 AM EDT SUN JUL 15 2012 .SYNOPSIS... THE COMBINATION OF A MID-LEVEL DISTURBANCE CROSSING THE GREAT LAKES AND A MOIST AIR MASS IN PLACE ACROSS THE UPPER OHIO VALLEY WILL MAKE SHOWERS AND THUNDERSTORMS LIKELY BY THIS AFTERNOON. A DRY START TO THE WEEK IS THEN EXPECTED AS HIGH PRESSURE ALOFT APPROACHES FROM THE SOUTHWEST. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... THE LATEST RAP MID-LEVEL ANALYSIS INDICATES THE UPPER OHIO VALLEY IN A SOUTHWESTERLY FLOW BETWEEN A RIDGE ACROSS THE CAROLINAS AND A TROUGH ACROSS THE WESTERN GREAT LAKES. AT THE SURFACE, DISCERNIBLE FRONTAL/PRESSURE FEATURES ARE LACKING WITH A BROAD AREA OF TDS IN THE UPPER 60S TO LOWER 70S ACROSS THE REGION. A SATURATED ATMOSPHERIC COLUMN REMAINS IN PLACE WITH PRECIPITABLE WATER VALUES IN THE 1.8-2.0 INCH RANGE EARLY THIS MORNING. DESPITE ONLY WEAK CAPE REMAINING, ABUNDANT MOISTURE IN PLACE IS ENOUGH TO SUPPORT WIDELY SCATTERED SHOWERS MOVING ACROSS THE AREA. THE SOUTHWESTERLY MID-LEVEL FLOW WILL BECOME MORE ZONAL TODAY AS THE TROUGH CROSSES THE GREAT LAKES. 500MB HEIGHTS WILL FALL SLIGHTLY AS THIS FEATURE PASSES NORTH OF THE AREA, PROVIDING ENOUGH FORCING IN A MOIST AND UNSTABLE ENVIRONMENT TO CONTRIBUTE TO THE DEVELOPMENT OF SHOWERS AND THUNDERSTORMS. COVERAGE OF CONVECTION IS EXPECTED TO INCREASE THIS MORNING AS ELEVATED INSTABILITY INCREASES FROM THE SOUTHWEST. EXPECT MOSTLY CLOUDY SKIES AGAIN TODAY WITH ABUNDANT MOISTURE. FOR TEMPS, HIGHS ARE CLOSEST TO MAV GUIDANCE, RANGING FROM THE UPPER 70S ALONG THE I-80 CORRIDOR AND EASTERN RIDGES TO THE MID 80S IN EASTERN OHIO. PWAT VALUES NEAR 2 INCHES WITH DEEP MOISTURE IN PLACE ALONG WITH MODERATE INSTABILITY WILL SUPPORT LOCALLY HEAVY DOWNPOURS TODAY. STORM MOTION OF AROUND 30KTS ALONG WITH THE GROUND BEING RELATIVELY DRY ACROSS MUCH OF THE AREA WILL BE LIMITING FACTORS FOR A FLASH FLOODING THREAT TODAY. HOWEVER, IF MULTIPLE STORMS TRAIN OVER AREAS, FLOODING COULD BECOME A THREAT. WITH 0-6KM BULK SHEAR AROUND 30KTS, ITS NOT OF THE QUESTION THAT A FEW ISOLATED STRONG TO SEVERE THUNDERSTORMS WILL DEVELOP THIS AFTERNOON INTO THE EVENING WITH THE PRIMARY THREAT BEING OF GUSTY WINDS AIDED BY MOISTURE LOADING. && .SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/... THERE IS OPERATIONAL MODEL AGREEMENT THAT THE MID-LEVEL TROUGH WILL SHIFT EAST OF THE AREA WITH THE FLOW BECOMING NORTHWESTERLY. WITH DEEP LAYER MOISTURE ADVECTING EAST OF THE AREA, CONVECTION WITH LOCALLY HEAVY DOWNPOURS WILL DIMINISH BY 06Z WITH POPS DECREASING TO SCHC QUICKLY AND DRY BY MONDAY MORNING. A DRY LAYER ABOVE 850MB ALONG WITH 500MB RIDGING BUILDING INTO THE OHIO VALLEY WILL ALLOW FOR A MOSTLY DRY FORECAST THROUGH THE DAY MONDAY AND INTO MONDAY NIGHT. MODERATE INSTABILITY MAY BE ENOUGH TO INITIATE AN ISOLATED SHOWER OR THUNDERSTORM SOUTHEAST OF PITTSBURGH INTO THE AFTERNOON. HIGHS MONDAY ARE A MAV/MET BLEND, RANGING FROM THE MID TO UPPER 80S ACROSS THE AREA. WITH TDS IN THE MID TO UPPER 60S TONIGHT AND MONDAY NIGHT, LOWS WILL RANGE FROM THE MID 60S ACROSS THE I-80 CORRIDOR TO NEAR 70 FOR THE PITTSBURGH METRO AND LOCATIONS SOUTHWESTWARD. ECMWF/GFS ARE IN AGREEMENT THAT THE 500MB RIDGE CENTERED ACROSS THE TENNESSEE VALLEY WILL EDGE TOWARD THE UPPER OHIO VALLEY ON TUESDAY. IN ADDITION, THE REGION WILL BE IN WARM AIR ADVECTION AHEAD OF A COLD FRONT APPROACHING FROM THE NORTHWEST. WITH 850MB TEMPS FORECAST TO WARM TO NEAR 20C BY TUESDAY AFTERNOON, THIS SUPPORTS HIGHS IN THE LOWER 90S ACROSS LOWLAND AREAS. WITH WARMEST TDS IN EASTERN OHIO, HEAT INDICES WILL APPROACH 100 AND A HEAT ADVISORY MAY BE NEEDED FOR LOCATIONS ALONG AND WEST OF I-77. TUESDAY WILL BE A WARM AND MUGGY NIGHT WITH TEMPS ONLY COOLING INTO THE LOWER 70S. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... A COLD FRONT IS PROGGED TO MOVE SLOWLY SOUTHWARD ACROSS THE GREAT LAKES AND THROUGH THE UPPER OHIO VALLEY ON WEDNESDAY. SCATTERED SHOWERS AND THUNDERSTORMS WILL ACCOMPANY THIS BOUNDARY THROUGH WEDNESDAY EVENING. DRY CONDITIONS CAN BE EXPECTED THURSDAY THROUGH SATURDAY AS SURFACE HIGH PRESSURE BUILDS IN ACROSS THE GREAT LAKES AND INTO NEW ENGLAND. STAYED CLOSE TO HPC NUMBERS WITH TEMPERATURES REMAINING BETWEEN 5 AND 10 DEGREES ABOVE NORMAL THROUGH WEDNESDAY NIGHT...THEN CLOSER TO NORMAL FOR THE LATTER PART OF THE WEEK. && .AVIATION /08Z SUNDAY THROUGH THURSDAY/... THUNDERSTORMS HAVE CLEARED ALL SITES TO THE NORTHEAST FOR THE EVENING AS OF 0530Z. SOME SHOWER ACTIVITY CONTINUES TO DEVELOP OVER EASTERN OHIO AND MOVE NORTHEASTWARD...BUT IT IS RATHER SCATTERED. THIS WILL NOT BE CARRIED AT ANY PARTICULAR TERMINAL...HOWEVER CONTINUED INPUT OF MOISTURE INTO THE LOWER LEVELS FROM ANY ADDITIONAL SHOWERS WILL ONLY INCREASE THE LIKELIHOOD OF VISIBILITIES STARTING TO SLIDE OFF WITHIN THE NEXT 1-3 HOURS. ALL SITES SHOULD GO MVFR PER BOTH STATISTICAL GUIDANCE AND PER SUGGESTIONS FROM BUFKIT DATA. SHOWERS WILL REDEVELOP BY LATE MORNING SUNDAY AGAIN AS THINGS BEGIN TO DESTABILIZE...WHICH SHOULD ALLOW FOR FOG TO BREAKUP BY THAT TIME. FRIES OUTLOOK...SUNDAY NIGHT THROUGH THURSDAY... WEAK RIDGING SHOULD PROVIDE GENERALLY VFR CONDITIONS MONDAY INTO TUESDAY. A COLD FRONT WILL SAG SOUTHWARD ACROSS THE GREAT LAKES AND THROUGH THE OHIO VALLEY TUESDAY NIGHT AND WEDNESDAY. RESTRICTIONS CAN BE EXPECTED IN SCATTERED PREFRONTAL THUNDERSTORMS. PREVAILING VFR WEATHER SHOULD RETURN BY THURSDAY AS A SURFACE HIGH BUILDS IN. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
228 AM EDT SUN JUL 15 2012 .SYNOPSIS... A LOW PRESSURE TROUGH ACROSS THE MISSISSIPPI VALLEY WILL CONTINUE TO CHANNEL HUMID CONDITIONS NORTHWARD ACROSS THE UPPER OHIO VALLEY TODAY, MAKING SHOWERS AND THUNDERSTORMS LIKELY. A DRY START TO THE WEEK IS EXPECTED AS HIGH PRESSURE ALOFT APPROACHES FROM THE SOUTHWEST. && .NEAR TERM /THROUGH TODAY/... 06Z ENHANCED SHORT TERM FORECAST UPDATE HAS BEEN ISSUED THIS MORNING TO REMOVE THUNDER FROM THE FORECAST THROUGH 14Z. THE LATEST RAP MID-LEVEL ANALYSIS INDICATES THE UPPER OHIO VALLEY IN A SOUTHWESTERLY FLOW BETWEEN A RIDGE ACROSS THE CAROLINAS AND A TROUGH ACROSS THE WESTERN GREAT LAKES. AT THE SURFACE, DISCERNIBLE FRONTAL/PRESSURE FEATURES ARE LACKING WITH A BROAD AREA OF TDS IN THE UPPER 60S TO LOWER 70S ACROSS THE REGION. A SATURATED ATMOSPHERIC COLUMN REMAINS IN PLACE WITH PRECIPITABLE WATER VALUES IN THE 1.8-2.0 INCH RANGE EARLY THIS MORNING. DESPITE ONLY WEAK CAPE REMAINING, ABUNDANT MOISTURE IN PLACE IS ENOUGH TO SUPPORT SCATTERED SHOWERS MOVING ACROSS THE AREA. THE SOUTHWESTERLY MID-LEVEL FLOW WILL BECOME MORE ZONAL TODAY AS THE TROUGH CROSSES THE GREAT LAKES. 500MB HEIGHTS WILL LOWER SLIGHTLY AS THIS FEATURE PASSES NORTH OF THE AREA, PROVIDING ENOUGH FORCING IN A MOIST AND UNSTABLE ENVIRONMENT TO CONTRIBUTE TO THE DEVELOPMENT OF SHOWERS AND THUNDERSTORMS. COVERAGE OF CONVECTION IS EXPECTED TO INCREASE THIS MORNING AS ELEVATED INSTABILITY INCREASES FROM THE SOUTHWEST. PWAT VALUES NEAR 2 INCHES WITH DEEP MOISTURE IN PLACE ALONG WITH MODERATE INSTABILITY WILL SUPPORT LOCALLY HEAVY DOWNPOURS. STORM MOTION OF AROUND 30KTS ALONG WITH THE GROUND BEING RELATIVELY DRY ACROSS MUCH OF THE AREA WILL CONTRIBUTE TO LIMIT THE FLASH FLOODING THREAT TODAY, SO NO MENTION IN THE HWO AT TIME. HOWEVER, IF MULTIPLE STORMS TRAIN OVER AREAS WHICH BECOME SATURATED, FLOODING COULD BECOME A THREAT. FOR TEMPS, HIGHS ARE CLOSEST TO MAV GUIDANCE, RANGING FROM THE LOWER TO MID 80S ACROSS THE UPPER OHIO VALLEY. && .SHORT TERM /TONIGHT THROUGH 6 PM MONDAY/... THERE IS OPERATIONAL MODEL AGREEMENT THAT THE MID-LEVEL TROUGH WILL SHIFT EAST OF THE AREA, WITH THE FLOW BECOMING NORTHWESTERLY. WITH DEEP LAYER MOISTURE ADVECTING EAST OF THE AREA, THIS WILL DECREASE POPS TO SCHC QUICKLY OVERNIGHT AND DRY BY MONDAY MORNING. A DRY LAYER ABOVE 850MB ALONG WITH 500MB RIDGING BUILDING INTO THE OHIO VALLEY WILL ALLOW FOR A DRY FORECAST THROUGH THE DAY MONDAY. HIGHS ARE A MAV/MET BLEND, RANGING FROM THE MID TO UPPER 80S ACROSS THE AREA. && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... A COLD FRONT IS PROGGED TO MOVE SLOWLY SOUTHWARD ACROSS THE GREAT LAKES AND THROUGH THE UPPER OHIO VALLEY TUESDAY NIGHT AND WEDNESDAY. SCATTERED SHOWERS AND THUNDERSTORMS WILL ACCOMPANY THIS BOUNDARY THROUGH WEDNESDAY EVENING. DRY CONDITIONS CAN BE EXPECTED THURSDAY THROUGH SATURDAY AS SURFACE HIGH PRESSURE BUILDS IN ACROSS THE GREAT LAKES AND INTO NEW ENGLAND. STAYED CLOSE TO HPC NUMBERS WITH TEMPERATURES REMAINING BETWEEN 5 AND 10 DEGREES ABOVE NORMAL THROUGH WEDNESDAY NIGHT...THEN CLOSER TO NORMAL FOR THE LATTER PART OF THE WEEK. && .AVIATION /06Z SUNDAY THROUGH THURSDAY/... THUNDERSTORMS HAVE CLEARED ALL SITES TO THE NORTHEAST FOR THE EVENING AS OF 0530Z. SOME SHOWER ACTIVITY CONTINUES TO DEVELOP OVER EASTERN OHIO AND MOVE NORTHEASTWARD...BUT IT IS RATHER SCATTERED. THIS WILL NOT BE CARRIED AT ANY PARTICULAR TERMINAL...HOWEVER CONTINUED INPUT OF MOISTURE INTO THE LOWER LEVELS FROM ANY ADDITIONAL SHOWERS WILL ONLY INCREASE THE LIKELIHOOD OF VISIBILITIES STARTING TO SLIDE OFF WITHIN THE NEXT 1-3 HOURS. ALL SITES SHOULD GO MVFR PER BOTH STATISTICAL GUIDANCE AND PER SUGGESTIONS FROM BUFKIT DATA. SHOWERS WILL REDEVELOP BY LATE MORNING SUNDAY AGAIN AS THINGS BEGIN TO DESTABILIZE...WHICH SHOULD ALLOW FOR FOG TO BREAKUP BY THAT TIME. FRIES OUTLOOK...SUNDAY NIGHT THROUGH THURSDAY... WEAK RIDGING SHOULD PROVIDE GENERALLY VFR CONDITIONS MONDAY INTO TUESDAY. A COLD FRONT WILL SAG SOUTHWARD ACROSS THE GREAT LAKES AND THROUGH THE OHIO VALLEY TUESDAY NIGHT AND WEDNESDAY. RESTRICTIONS CAN BE EXPECTED IN SCATTERED PREFRONTAL THUNDERSTORMS. PREVAILING VFR WEATHER SHOULD RETURN BY THURSDAY AS A SURFACE HIGH BUILDS IN. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
522 AM EDT SUN JUL 15 2012 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 520 AM EDT SUN JUL 15 2012 WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW TROF JUST E OF THE FCST AREA. SHRA/TSRA THAT ACCOMPANIED THE TROF ACROSS THE AREA YESTERDAY HAVE RECENTLY EXITED THE SE PORTION OF THE FCST AREA. IN ITS WAKE... CALM WIND/CLEARING SKIES AND MOISTURE FROM YESTERDAY`S RAINFALL HAS LED TO SOME FOG DEVELOPMENT. FOG WILL QUICKLY BURN OFF WITHIN A COUPLE HRS AFTER SUNRISE. UPSTREAM...A MID LEVEL RIDGE IS NOSING INTO THE DAKOTAS/WRN MN. AS THE RIDGE SHIFTS E TODAY...UPPER MI WILL FALL UNDER HEIGHT RISES/DEEP LAYER QVECTOR DIVERGENCE. MUCH DRIER AIR...MAINLY IN THE MID LEVELS PER UPSTREAM 00Z KINL/CWPL SOUNDINGS...WILL WORK AGAINST ANY AFTN CONVECTIVE DEVELOPMENT DESPITE LAKE BREEZES PROVIDING LOW-LEVEL FORCING. THE K-INDEX ON THE 00Z CWPL/KINL SOUNDINGS WAS -11/-14C RESPECTIVELY DUE TO VERY DRY AIR AROUND 700MB (DWPT DEPRESSIONS WERE IN EXCESS OF 40C). SO... GOING DRY FCST APPEARS ON TRACK DESPITE SOME HIGH RES GUIDANCE CONTINUING TO SHOW ISOLD CONVECTION OVER THE SCNTRL THIS AFTN. MIXING TO AROUND 800MB ON FCST SOUNDINGS SUPPORTS MAX TEMPS UPWARDS OF AROUND 90F. LIGHT GRADIENT WIND WILL ALLOW LAKE BREEZES OFF LAKE SUPERIOR AND LAKE MICHIGAN TO PROVIDE SOME COOLING LAKESIDE. SHORTWAVE ENERGY EJECTING FROM THE TROF CURRENTLY OVER THE WRN STATES WILL HEAD INTO SCNTRL CANADA TONIGHT. IN RESPONSE...LOW-LEVEL JET WILL INCREASE TO 45-50KT INTO THE NRN PLAINS. THIS WILL LIKELY SUPPORT A CLUSTER OF SHRA/TSRA ON THE NOSE OF THE LOW-LEVEL JET AND ALONG EDGE OF CAP ACROSS ND INTO SRN MANITOBA/NRN MN AND NRN ONTARIO. AT THIS TIME...IT STILL APPEARS LOW-LEVEL JET WILL BE W OF THE AREA AT 12Z MON...SO DO NOT ANTICIPATE ANY CONVECTION LATE TONIGHT...EXCEPT POSSIBLY OVER NW LAKE SUPERIOR/ISLE ROYALE. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 520 AM EDT SUN JUL 15 2012 BY 12Z MONDAY THE FRONTAL BOUNDARY WOULD BE ACROSS LAKE SUPERIOR /AS A WARM FRONT/...STRETCHING FROM THE SFC LOW SET UP FROM NW MN TO CENTRAL SD. DEPENDING ON THE AMOUNT OF MIXING /UP TO AROUND 800MB AT SAW/ A FEW GUSTS OF 30 TO 35KTS COULD BE POSSIBLE FROM LATE MORNING THROUGH THE REMAINDER OF THE DAYTIME HOURS. IF CLOUD COVER DOES NOT INHIBIT MIXING...THESE STRONGER GUSTS COULD BE POSSIBLE ACROSS THE DOWNSLOPE LOCATIONS NEAR LAKE SUPERIOR GIVEN THE STRENGTHENING SW FLOW. AS FOR THE OFFICIAL FCST...HAVE INCREASED WINDS QUITE A BIT FROM THE PREVIOUS FORECAST...WITH GUSTS OF 20-25KTS ACROSS MUCH OF THE CWA BY MID AFTERNOON. THE RECORD HIGH TEMP FOR MONDAY AT WFO MQT IS 95 DEGREES...WHICH MAY BE BROKEN BY THE END OF THE DAY. CURRENTLY GOING ONLY A COUPLE OF DEGREES COOLER THAN THIS RECORD...WITH 850MB TEMPS OF 22-24C ALLOWING SEVERAL SITES ACROSS THE INTERIOR W HALF OF UPPER MI REACHING 95 OR ABOVE. THE SFC LOW SHOULD PUSH ACROSS THE AREA MONDAY AFTERNOON THROUGH TUESDAY NIGHT. THE TRACK IS STILL UNCERTAIN...WITH THE 14/18Z GFS AND 15/00Z NAM PUSHING THE SFC LOW ACROSS THE KEWEENAW PENINSULA AND ACROSS LAKE SUPERIOR BY EARLY MONDAY EVENING. THE FARTHER SOUTH 14/12Z ECMWF INDICATES A BROADER LOW...STRETCHING ACROSS CENTRAL AND SOUTHERN UPPER MI MONDAY NIGHT. THE 14/12Z CANADIAN IS BEYOND CONSENSUS FROM MONDAY AFTERNOON ON...TRACKING THE SFC LOW ACROSS ONTARIO AND N LAKE SUPERIOR...AND WILL NOT BE USED IN THIS FORECAST UNTIL IT MOVES BACK IN LINE WITH THE REMAINDER OF AVAILABLE GUIDANCE WEDNESDAY MORNING. HIGH PRESSURE OVER CENTRAL CANADA TUESDAY MORNING WILL SLOWLY SHIFT SE ACROSS LAKE SUPERIOR AND UPPER MI TUESDAY THROUGH THURSDAY. THE COOLEST AFTERNOON TEMPS LOOK TO BE WEDNESDAY...TOPPING OUT IN THE 70S...COOLEST NEAR LAKE SUPERIOR AS DRY COOL AIR REMAINS. 850MB TEMPS WEDNESDAY WILL BE A COOL 10-12C. THE FCST FOR THE CWA WILL REMAIN DRY TUESDAY NIGHT THROUGH FRIDAY NIGHT. EXPECT THE SFC HIGH TO DRIFT E TO THE LOWER GREAT LAKES AND W QUEBEC BY DAYBREAK FRIDAY AND THE NEW ENGLAND COAST FRIDAY NIGHT...WITH A RIDGE REMAINING ACROSS THE UPPER GREAT LAKES REGION. A RELATIVELY WEAK SFC LOW STRETCHING FROM CENTRAL CANADA THROUGH THE CENTRAL PLAINS LOOKS TO BECOME BETTER ORGANIZED TO OUR W SATURDAY NIGHT...AS A SERIES OF DISTURBANCES NEAR FROM W AND CENTRAL CANADA AS 500MB RIDGE BECOMES SUPPRESSED ACROSS THE CENTRAL AND SOUTHERN PLAINS. KEPT CHANCE POPS FOR SATURDAY...ALTHOUGH CONFIDENCE IS MODERATE TO LOW FOR SPECIFICS THAT FAR OUT IN THIS FCST. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 132 AM EDT SUN JUL 15 2012 GIVEN CLEARING SKIES AND ADDITIONAL LOW-LEVEL MOISTURE FM RECENT RAINFALL...EXPECT STRATUS/FOG TO DEVELOP OVER MUCH OF UPPER MI. CONFIDENCE IS FAIRLY HIGH THAT FOG WILL BRING KSAW VSBY AND CIGS DOWN TO LIFR AND POSSIBLE VLIFR CONDITIONS OVERNIGHT AS RAINFALL WAS MORE ABUNDANT IN THAT AREA ON SATURDAY. AT IWD AND CMX...LESSER RAINFALL ON SATURDAY CASTS SOME UNCERTAINTY AS TO FOG POTENTIAL OVERNIGHT. HAVE ALREADY SEEN LOWER STRATUS DECK FORM AT CMX...AND THOUGH THAT MAY BE INTERMITTENT INITIALLY FOR THE OVERNIGHT HOURS DUE TO BLOWOFF CLOUDS OVR WESTERN LK SUPERIOR...WILL GO WITH IDEA THAT STRATUS AND IFR FOG STAY IN THERE OVERNIGHT. MAY EVEN SEE LOWER VSBY LATER TONIGHT BRIEFLY IF THE BLOWOFF DISIPPATES COMPLETELY. AT IWD WILL KEEP WITH AN MVFR VSBY FOR JUST PATCHY FOG. ALL CIG/VSBY REDUCTION WILL BE DONE SHORTLY AFT SUNRISE. EXPECT VFR CONDITIONS FROM MID MORNING THRU THE END OF THE FCST PERIOD. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 520 AM EDT SUN JUL 15 2012 BIGGEST CONCERN IN THE SHORT TERM WILL BE FOG. 11-3.9MICRON SATELLITE IMAGERY INDICATES FOG (PROBABLY NOT STRATUS) EXPANDING S AND E FROM NCNTRL LAKE SUPERIOR. MORE FOG MAY BE DEVELOPING FROM KEWEENAW BAY TOWARD MARQUETTE/MUNISING. WITH DEVELOPING MESO HIGH PRES OVER THE LAKE TODAY...IT`S QUITE POSSIBLE FOG MAY END UP SPREADING TO THE SHORELINES AROUND THE ENTIRE LAKE TODAY. ALWAYS DIFFICULT TO FCST MARINE FOG...SO TRENDS WILL NEED TO MONITORED CLOSELY TODAY FOR MOVEMENT/DEVELOPMENT/DISSIPATION OF FOG. ONCE DAYLIGHT ARRIVES...VIS SATELLITE IMAGERY WILL PROVIDE A BETTER LOOK AT HOW THE FOG IS EVOLVING. QUITE POSSIBLE DENSE FOG ADVY MAY NEED TO BE ISSUED. FOR NOW...CARRIED FOG MENTION THRU EARLY AFTN OVER MAINLY CNTRL AND ERN LAKE SUPERIOR. OTHERWISE...WITH HIGH PRES DEVELOPING OVER LAKE SUPERIOR TODAY... WINDS WILL BE UNDER 15KT. ALTHOUGH WINDS WILL BECOME S-SE TONIGHT IN ADVANCE OF APPROACHING LOW PRES...SPEEDS SHOULD REMAIN 15KT OR LESS. THERE IS SOME UNCERTAINTY IN WHERE WARM FRONT ASSOCIATED WITH THE LOW WILL BE POSITIONED MON. AT THIS TIME...IT APPEARS THAT AT LEAST SRN PORTIONS OF THE LAKE WILL SEE INCREASING S-SW WINDS MON UPWARDS OF 20KT AS WARM FRONT DRIFTS N. AS LOW PASSES ACROSS THE AREA MON NIGHT...A COLD FRONT WILL PUSH S...BRINGING A SHIFT TO NORTHERLY WINDS UPWARDS OF 20KT INTO TUE MORNING. HIGH PRES WILL THEN BUILD INTO THE UPPER GREAT LAKES DURING THE MIDWEEK PERIOD...RESULTING IN WINDS UNDER 20KT. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...ROLFSON LONG TERM...KF AVIATION...JLA MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS BUFFALO NY
552 AM EDT SUN JUL 15 2012 .SYNOPSIS... A SOUTHWESTERLY FLOW WILL BRING INCREASINGLY HUMID AIR INTO THE REGION TODAY ALONG WITH SOME SHOWERS AND THUNDERSTORMS. A FEW STORMS WILL CONTAIN LOCALLY HEAVY RAINFALL...BUT ANY HEAVIER RAIN AMOUNTS WILL BE SPOTTY. A RIDGE OF HIGH PRESSURE WILL BUILD INTO THE LOWER GREAT LAKES MONDAY WITH MAINLY DRY CONDITIONS. && .NEAR TERM /THROUGH TONIGHT/... TODAY WILL BRING AN OPPORTUNITY FOR DROUGHT RELIEF...HOWEVER SHOWERS AND THUNDERSTORMS WILL BE PATCHY IN NATURE...SO MANY COULD MISS OUT. THERE APPEARS TO BE TWO FEATURES WHICH WILL KEY THIS ACTIVITY. THE FIRST IS A MODEST 25 KT LOW LEVEL JET FOUND AT 925 MB...WHICH IS KEYING THE ADVANCE OF LOW LEVEL MOISTURE. THE SECOND IS AN UPPER LEVEL TROF AXIS...WHICH WILL CROSS THE REGION LATE AFTERNOON INTO THIS EVENING. AS IS OFTEN THE CASE...MODEL GUIDANCE IS STRUGGLING A BIT WITH CONVECTION...WITH A FAIR SPREAD OF QPF SOLUTIONS BETWEEN THE NAM/RGEM/GFS/EUROPEAN/SREF. THE HRRR HAS ALSO BEEN INCONSISTENT RUN TO RUN AND HAS BEEN LATE IN CATCHING ON TO CONVECTION WHICH HAS DEVELOPED. GIVEN THIS SCENARIO WILL TEND TO WEIGHT RADAR TRENDS IN THE NEAR TERM...AND A SREF WEIGHTED ENSEMBLE OF AVAILABLE GUIDANCE FROM LATE MORNING ON. THIS SUGGESTS FAIRLY MODEST SHOWER ACTIVITY WILL MOVE ACROSS THE REGION THROUGH MID TO LATE MORNING...WITH THE BEST CHANCE FOR THIS SOUTH OF LAKE ONTARIO. EXPECT SHOWERS TO BE HIT AND MISS. THERE SEEMS TO BE A FAIR CONSENSUS THAT THE MOST SIGNIFICANT RAINS WILL COME LATE MORNING AND EARLY AFTERNOON. THIS MAKES SENSE GIVEN THE APPROACH OF A SLOW MOVING UPPER LEVEL TROF AND THE CONTRIBUTION OF DAYTIME HEATING. THIS WILL LIKELY BRING SHOWERS AND THUNDERSTORMS TO THE SOUTHERN TIER AND INTO THE FINGER LAKES REGION...AND PERHAPS ELSEWHERE THOUGH COVERAGE SHOULD BE A BIT MORE SPARSE. CONVECTION WILL FORM ALONG ANY BOUNDARY IT CAN FIND...BUT HAVE SOME CONCERN MUCH OF THE BUFFALO METRO AREA (AND WATERTOWN FOR THAT MATTER) WILL MISS OUT IN A SOUTHWEST FLOW WHICH CAN TEND TO SHADOW THE REGION FROM AFTERNOON CONVECTION. AS HAS BEEN THE CASE THE PAST TWO DAYS...THE FLOW ALOFT WILL BE FAIRLY LIGHT. HOWEVER...TODAY THE PRECIPITABLE WATER VALUES WILL BE SIGNIFICANTLY GREATER...BETWEEN 1.75 INCHES AND 2.00 INCHES. IF IT WERE NOT FOR THE VERY DRY CONDITIONS IN PLACE...THIS WOULD POSE A GREATER FLOODING THREAT...BUT EVEN STILL THERE IS A REAL POTENTIAL FOR FLOODING ALBEIT LOCALIZED. HAVE THE MOST CONCERN FOR THE SOUTHERN TIER...WHERE TERRAIN CAN FUNNEL RUNOFF. DUE TO THE HIT OR MISS NATURE OF CONVECTION...MEAN QPFS COULD BE A BIT MISLEADING. WHILE BASIN-WIDE QPF FORECASTS RANGE FROM NEAR A HALF INCH EXPECTED IN THE SOUTHERN TIER DOWN TO A TENTH OF AN INCH NORTH AND WEST OF I-90...RAINFALL BY LOCATION SHOULD VARY SIGNIFICANTLY. THE UPPER TROF WILL SLOWLY MOVE ACROSS THE REGION BY THIS EVENING...BUT BY THIS TIME...DRIER AIR SHOULD BE IN PLACE IN THE BOUNDARY LAYER...SO SHOWER AND THUNDERSTORMS SHOULD TAPER OFF AND/OR EXIT EAST. THE WEAK FRONTAL BOUNDARY ASSOCIATED WITH THE TROF WILL NOT ACTUALLY CROSS THE REGION TONIGHT. THIS WILL KEEP MOIST AIR IN PLACE...AND DEPENDING ON RAINFALL TODAY COULD RESULT IN AREAS OF FOG TONIGHT. TEMPERATURES WILL BE A BIT COOLER TODAY THAN THEY WERE YESTERDAY...HOWEVER INCREASED MOISTURE WILL MAKE IT FEEL MORE MUGGY. HIGHS SHOULD BE IN THE LOWER 80S NORTH OF THE THRU-WAY...BUT MAY STAY IN THE UPPER 70S IN THE SOUTHERN TIER WHERE CLOUDS AND SHOWERS SHOULD LIMIT TEMPERATURES A BIT. FOR TONIGHT...LOWS WILL RANGE FROM THE LOWER 60S IN THE SOUTHERN TIER...TO AROUND 70 IN THE BUFFALO/ROCHESTER METRO AREAS. && .SHORT TERM /MONDAY THROUGH WEDNESDAY/... DURING THE COURSE OF MONDAY...THE AXIS OF A WEAK UPPER LEVEL TROUGH DRAPED FROM THE NEW ENGLAND COAST TO THE MID ATLANTIC STATES WILL SLIDE OUT TO SEA...ALLOWING THE LEADING EDGE OF BROAD/FLAT UPPER RIDGING TO EDGE NORTHEAST INTO THE LOWER LAKES. MEANWHILE AT THE SURFACE...LINGERING WEAK TROUGHINESS ACROSS THE LOWER LAKES AT THE START OF THE DAY WILL ALSO SLIDE EASTWARD...GIVING WAY TO MODEST LOW LEVEL RIDGING DURING THE AFTERNOON. GIVEN THESE DEVELOPMENTS...EXPECT THAT MONDAY SHOULD LARGELY BE ANOTHER DRY AND HOT/HUMID DAY...WITH 850 MB TEMPS OF +16C/+17C AGAIN SUPPORTING WIDESPREAD HIGHS IN THE UPPER 80S/LOWER 90S GIVEN WHAT SHOULD BE A DECENT AMOUNT OF SUNSHINE. WHILE BOTH THE GFS AND ECMWF BOTH SPIT OUT SOME LIGHT QPF ACROSS THE AREA PRIOR TO THE DEPARTURE OF THE LOW LEVEL TROUGH...BELIEVE THAT THIS IS OVERDONE GIVEN ONLY WEAK LINGERING FORCING AND FAIRLY WARM MID LEVEL TEMPS...WHICH SHOULD HELP TO KEEP ANY PRECIP ISOLATED IN COVERAGE AT BEST. HAVE THEREFORE KEPT POPS AT THE VERY LOW END OF THE SLIGHT CHANCE RANGE OR BELOW ON MONDAY. MONDAY NIGHT...BROAD/FLAT UPPER RIDGING WILL REMAIN INTACT ACROSS MUCH OF THE AREA...WHILE A SLOW MOVING COLD FRONTAL BOUNDARY OVER CENTRAL ONTARIO PROVINCE SAGS SOUTHWARD INTO THE UPPER LAKES AND SOUTHERN ONTARIO. WHILE I CANNOT TOTALLY RULE OUT SOME ASSOCIATED ISOLATED CONVECTION SNEAKING INTO THE SAINT LAWRENCE VALLEY TOWARD DAYBREAK ON TUESDAY...IT DOES APPEAR THAT THE FRONT WILL REMAIN FAR ENOUGH TO OUR NORTH AND THAT WE WILL REMAIN CAPPED ENOUGH FOR MAINLY DRY WEATHER TO CONTINUE AREAWIDE. WITH NO AIRMASS CHANGE AND AN INCREASING SOUTHWESTERLY LOW LEVEL FLOW EXPECTED WITH TIME IN RESPONSE TO THE APPROACHING FRONT...EXPECT DOWNRIGHT SULTRY TEMPERATURES WITH OVERNIGHT LOWS RANGING FROM THE MID AND UPPER 60S ACROSS INTERIOR SECTIONS...TO THE LOWER 70S ACROSS THE LAKE PLAINS. ON TUESDAY...THE AFOREMENTIONED FRONT WILL CONTINUE TO SLOWLY SAG SOUTH TOWARD OUR REGION...WITH NOTABLE TIMING DIFFERENCES SEEN AMONGST THE VARIOUS GUIDANCE PACKAGES. THE 00Z NAM IS AN EXTREMELY FAST OUTLIER THAT BRINGS THE FRONT COMPLETELY THROUGH THE AREA BY THE END OF THE DAY...WHICH SEEMS HIGHLY UNLIKELY GIVEN ITS NEAR-PARALLEL ORIENTATION TO THE UPPER LEVEL FLOW...NOT TO MENTION THE PROPENSITY FOR SUCH BOUNDARIES TO GET HUNG UP ACROSS THE LOWER LAKES AT THIS TIME OF YEAR. FOR THIS REASON...HAVE COMPLETELY DISREGARDED THIS SOLUTION. OF THE REMAINING GUIDANCE...THE GFS REMAINS A BIT ON THE FASTER SIDE THOUGH NOT AS FAST AS ITS PREVIOUS RUNS...BRINGING THE BOUNDARY INTO NORTHERN NEW YORK/LAKE ONTARIO BY THE END OF THE DAY...WHICH IS CLOSE ENOUGH TO GENERATE SOME CONVECTION ACROSS BOTH THE NORTH COUNTRY AND NIAGARA/ORLEANS COUNTIES. MEANWHILE...THE VERY CONSISTENT ECMWF REMAINS A TOUCH SLOWER THAN THE GFS AND ONLY BRINGS A RISK OF CONVECTION INTO THE NORTH COUNTRY...WITH THE 00Z GEM GLOBAL A BIT SLOWER STILL. AT THIS JUNCTURE...FEEL A COMPROMISE BETWEEN THE GFS/ECMWF REPRESENTS THE MOST PLAUSIBLE SCENARIO...WHICH WOULD BRING AT LEAST A LOW TO MODEST CHANCE OF CONVECTION TO LAKE ONTARIO AND THE NORTH COUNTRY BY LATE IN THE DAY. FURTHER TO THE SOUTH...CONDITIONS SHOULD REMAIN DRY THROUGH THE DAY ON TUESDAY...THANKS TO BOTH GREATER DISTANCE FROM THE FRONT AND STRONG MID LEVEL CAPPING...AS EVEN HOTTER AIR RIDES EAST ALONG THE PERIPHERY OF THE MAIN UPPER LEVEL RIDGE. A CONSENSUS OF THE GFS/GEM/ECMWF SUPPORTS 850 MB TEMPS RISING TO THE +20/+21C RANGE AREAWIDE DURING THE COURSE OF TUESDAY...AND THIS COUPLED WITH GOOD MIXING AND A DECENT AMOUNT OF SUN WILL LIKELY RESULT IN A REAL SCORCHER OF A DAY SOUTH OF LAKE ONTARIO. AT THIS POINT...WIDESPREAD HIGHS IN THE LOWER TO MID 90S APPEAR TO BE A SOLID BET...WITH UPPER 90S NOT AT ALL OUT OF THE QUESTION FOR THE NORMAL HOT SPOTS IN INTERIOR PORTIONS OF OUR CWA. COUPLED WITH DEWPOINTS IN THE MID TO UPPER 60S...SOME LOCATIONS SOUTH OF LAKE ONTARIO COULD SEE APPARENT TEMPERATURES REACHING THE 100 DEGREE MARK TUESDAY AFTERNOON...WHICH WOULD NECESSITATE THE ISSUANCE OF A HEAT ADVISORY. AS IT REMAINS FAR TOO EARLY FOR THAT...FOR NOW WILL JUST MENTION THIS POTENTIAL IN THE HWO. EAST OF LAKE ONTARIO...SOMEWHAT GREATER AMOUNTS OF CLOUD COVER WILL LIKELY HELP KEEP TEMPS A LITTLE COOLER...THOUGH IT SHOULD STILL BE UNCOMFORTABLY HOT EVEN THERE WITH HIGHS IN THE UPPER 80S TO LOWER 90S. TUESDAY NIGHT AND WEDNESDAY...THE COLD FRONT WILL SLOWLY SAG SOUTH ACROSS THE REGION...BRINGING A RISK OF CONVECTION TO THE ENTIRE CWA...ALONG WITH THE POTENTIAL FOR LOCALLY HEAVY RAINFALL GIVEN PRECIPITABLE WATER VALUES IN THE VICINITY OF AROUND 2 INCHES. AT THIS JUNCTURE...THE TIMING OF THIS BOUNDARY REMAINS AN ISSUE WITH THE GFS REMAINING THE FASTEST...THE CANADIAN THE SLOWEST...AND THE ECMWF IN THE MIDDLE...WITH FROPA TIMES RANGING BETWEEN EARLY TO MID WEDNESDAY MORNING AND WEDNESDAY AFTERNOON. GIVEN THAT THIS FRONT APPEARS TO BE ANAFRONTAL WITH MOST OF ITS PRECIP FALLING BEHIND THE ACTUAL SURFACE BOUNDARY...THIS MEANS THAT ANY ASSOCIATED CONVECTION COULD END AS EARLY AS SOMETIME WEDNESDAY MORNING...OR AS LATE AS THE END OF THE DAY WEDNESDAY. GIVEN THE CONTINUED UNCERTAINTIES IN TIMING AND THE AFOREMENTIONED NEAR-PARALLEL ORIENTATION OF THE FRONT TO THE UPPER FLOW...FEEL IT IS BEST TO SLOW DOWN THE TIMING OF THIS FRONT AND ITS ASSOCIATED CONVECTION A BIT FROM THE PREVIOUS FORECAST...FAVORING A COMPROMISE SOLUTION ALONG THE LINES OF THE ECMWF. AS A RESULT...CHANCES FOR CONVECTION WILL BE IN PLACE FROM TUESDAY NIGHT THROUGH WEDNESDAY MORNING ACROSS THE ENTIRE AREA...BEFORE DIMINISHING FROM NORTH TO SOUTH DURING THE COURSE OF WEDNESDAY AFTERNOON. TEMPERATURE-WISE... EXPECT ANOTHER SULTRY NIGHT IN ADVANCE OF THE FRONT TUESDAY NIGHT WITH LOWS AGAIN RANGING FROM THE UPPER 60S TO LOWER 70S...FOLLOWED BY SOMEWHAT COOLER HIGHS IN THE UPPER 70S TO MID 80S ON WEDNESDAY GIVEN THE PASSAGE OF THE FRONT AND ITS ASSOCIATED CLOUD COVER/PRECIP. && .LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/... SIMPLY PUT...SPRAWLING CANADIAN HIGH PRESSURE WILL BUILD SOUTHEAST ACROSS THE GREAT LAKES AND NORTHEAST DURING THIS PERIOD...BRINGING A RETURN TO DRY WEATHER ALONG WITH A COOLER AND NOTICEABLY LESS HUMID AIRMASS. IN TERMS OF ACTUAL TEMPERATURES...EXPECT DAILY HIGHS TO FALL BACK INTO THE MID 70S TO LOWER 80S FOR BOTH THURSDAY AND FRIDAY...BEFORE WARMING BACK INTO THE LOWER TO MID 80S ON SATURDAY AS WARMING COMMENCES ALOFT. MEANWHILE...NIGHTTIME LOWS WILL RANGE IN THE MID 50S TO LOWER 60S ALL THREE NIGHTS. HUMIDITY LEVELS WILL ALSO BE MUCH MORE COMFORTABLE...WITH DEWPOINTS REMAINING IN THE MID TO UPPER 50S DURING THE BULK OF THE PERIOD. && .AVIATION /10Z SUNDAY THROUGH THURSDAY/... THE THREAT FOR SHOWERS AND THUNDERSTORMS WILL INCREASE FROM SW TO NE BETWEEN 09Z AND 15Z AS A WEAK LOW LEVEL JET KEYS THE ADVANCE OF MOIST AIR. RADAR SUGGESTS THESE STORMS WILL BE SCATTERED IN NATURE...NOT IMPACTING ALL TAF SITES. MOISTURE IN THE LOW LAYERS MAY LOWER JHW TO IFR OR LOWER EARLY THIS MORNING...BUT AN APPROACHING THUNDERSTORM MAY MIX THIS OUT AROUND DAYBREAK. BEHIND THIS INITIAL AREA OF SHOWERS AND THUNDERSTORMS WILL BE ANOTHER OPPORTUNITY FOR CONVECTION WITH AN APPROACHING SHORTWAVE THIS AFTERNOON. LAKE SHADOWING WILL DIMINISH THE POTENTIAL AT BUF/IAG/ART...THOUGH THE LAKES ARE WARM ENOUGH THAT THUNDERSTORMS CANNOT COMPLETELY BE RULED OUT AT ANY TAF LOCATION. THIS SAID...THE BEST CHANCE FOR THUNDERSTORMS WILL BE OUT AHEAD OF THIS SHORTWAVE AT JHW/ROC EARLY THIS AFTERNOON. EXPECT A GENERAL CLEARING TREND FROM WEST TO EAST LATE THIS AFTERNOON AND EVENING. THIS SHOULD RESULT IN MAINLY VFR CONDITIONS...BUT THERE WILL BE AN INCREASING CHANCE FOR FOG OVERNIGHT. THE COMBINATION OF LIGHT WINDS AND LINGERING BOUNDARY LAYER MOISTURE MAY RESULT IN FAIRLY WIDESPREAD IFR OR LOWER CONDITIONS LATE TONIGHT...ESPECIALLY IF SKIES CLEAR OUT. OUTLOOK... MONDAY AND TUESDAY...MAINLY VFR. TUESDAY NIGHT...AREAS OF MVFR IN SCATTERED -SHRA/-TSRA. WEDNESDAY...BECOMING VFR. THURSDAY...VFR. && .MARINE... HIGH PRESSURE WILL REMAIN ANCHORED ALONG THE MID ATLANTIC COAST THROUGH EARLY NEXT WEEK. MEANWHILE A WEAK TROUGH WILL APPROACH THE LOWER LAKES TODAY AND ALLOW SOUTHWEST WINDS TO INCREASE SOMEWHAT TO THE 10-15 KNOT RANGE...WITH THE STRONGEST WINDS ON LAKE ERIE. EXPECT CONDITIONS TO REMAIN BELOW SMALL CRAFT CRITERIA...BUT WAVES MAY GET A LITTLE CHOPPY ON LAKE ERIE. A RIDGE OF HIGH PRESSURE WILL NOSE INTO THE LOWER LAKES MONDAY WITH RELATIVELY LIGHT WINDS. SOUTHWEST WINDS WILL PICK UP AGAIN TUESDAY AHEAD OF A STRONGER COLD FRONT...ESPECIALLY ON LAKE ERIE WHERE CONDITIONS MAY APPROACH SMALL CRAFT ADVISORY CRITERIA. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...NONE. MARINE...NONE. && $$ SYNOPSIS...APFFEL NEAR TERM...APFFEL SHORT TERM...JJR LONG TERM...JJR AVIATION...APFFEL MARINE...APFFEL/JJR
AREA FORECAST DISCUSSION
NWS BUFFALO NY
331 AM EDT SUN JUL 15 2012 .SYNOPSIS... A SOUTHWESTERLY FLOW WILL BRING INCREASINGLY HUMID AIR INTO THE REGION TODAY ALONG WITH SOME SHOWERS AND THUNDERSTORMS. A FEW STORMS WILL CONTAIN LOCALLY HEAVY RAINFALL...BUT ANY HEAVIER RAIN AMOUNTS WILL BE SPOTTY. A RIDGE OF HIGH PRESSURE WILL BUILD INTO THE LOWER GREAT LAKES MONDAY WITH MAINLY DRY CONDITIONS. && .NEAR TERM /THROUGH TONIGHT/... TODAY WILL BRING AN OPPORTUNITY FOR DROUGHT RELIEF...HOWEVER SHOWERS AND THUNDERSTORMS WILL BE PATCHY IN NATURE...SO MANY COULD MISS OUT. THERE APPEARS TO BE TWO FEATURES WHICH WILL KEY THIS ACTIVITY. THE FIRST IS A MODEST 25 KT LOW LEVEL JET FOUND AT 925 MB...WHICH IS KEYING THE ADVANCE OF LOW LEVEL MOISTURE. DEW POINTS HAVE RISEN TO AROUND 70 ACROSS OHIO EARLY THIS MORNING...WITH MODEST SHOWER ACTIVITY EXTENDING FROM SOUTHERN ONTARIO TO FAR SOUTHWESTERN NEW YORK. THIS IS LIFTING TO THE NE...AND SHOULD SPREAD FURTHER INTO THE CWA THROUGH MID-MORNING. AS IS OFTEN THE CASE...MODEL GUIDANCE IS STRUGGLING A BIT WITH CONVECTION...WITH A FAIR SPREAD OF QPF SOLUTIONS BETWEEN THE NAM/RGEM/GFS/EUROPEAN/SREF. THE HRRR HAS ALSO BEEN INCONSISTENT RUN TO RUN...AND GIVEN THIS SCENARIO WILL TEND TO WEIGHT RADAR TRENDS IN THE NEAR TERM...AND A SREF WEIGHTED ENSEMBLE OF AVAILABLE GUIDANCE FROM LATE MORNING ON. THIS SUGGESTS FAIRLY MODEST SHOWER ACTIVITY WILL MOVE ACROSS THE REGION THROUGH MID TO LATE MORNING...WITH THE BEST CHANCE FOR THIS SOUTH OF LAKE ONTARIO. EXPECT SHOWERS TO BE HIT AND MISS. THERE SEEMS TO BE A FAIR CONSENSUS THAT THE MOST SIGNIFICANT RAINS WILL COME EARLY AFTERNOON. THIS MAKES SENSE GIVEN THE APPROACH OF A SLOW MOVING UPPER LEVEL TROF AND THE CONTRIBUTION OF DAYTIME HEATING. THIS WILL LIKELY BRING SHOWERS AND THUNDERSTORMS TO THE SOUTHERN TIER AND INTO THE FINGER LAKES REGION...AND PERHAPS ELSEWHERE THOUGH COVERAGE SHOULD BE A BIT MORE SPARSE. CONVECTION WILL FORM ALONG ANY BOUNDARY IT CAN FIND...BUT HAVE SOME CONCERN MUCH OF THE BUFFALO METRO AREA (AND WATERTOWN FOR THAT MATTER) WILL MISS OUT IN A SOUTHWEST FLOW WHICH CAN TEND TO SHADOW THE REGION FROM AFTERNOON CONVECTION. AS HAS BEEN THE CASE THE PAST TWO DAYS...THE FLOW ALOFT WILL BE FAIRLY LIGHT. HOWEVER...TODAY THE PRECIPITABLE WATER VALUES WILL BE SIGNIFICANTLY GREATER...BETWEEN 1.75 INCHES AND 2.00 INCHES. IF IT WERE NOT FOR THE VERY DRY CONDITIONS IN PLACE...THIS WOULD POSE A GREATER FLOODING THREAT...BUT EVEN STILL THERE IS A REAL POTENTIAL FOR FLOODING ALBEIT LOCALIZED. HAVE THE MOST CONCERN FOR THE SOUTHERN TIER...WHERE TERRAIN CAN FUNNEL RUNOFF. DUE TO THE HIT OR MISS NATURE OF CONVECTION...MEAN QPFS COULD BE A BIT MISLEADING. WHILE BASIN-WIDE QPF FORECASTS RANGE FROM NEAR A HALF INCH EXPECTED IN THE SOUTHERN TIER DOWN TO A TENTH OF AN INCH NORTH AND WEST OF I-90...RAINFALL BY LOCATION SHOULD VARY SIGNIFICANTLY. THE UPPER TROF WILL SLOWLY MOVE ACROSS THE REGION THIS EVENING...BUT BY THIS TIME...DRIER AIR SHOULD BE IN PLACE IN THE BOUNDARY LAYER...SO SHOWER AND THUNDERSTORMS SHOULD TAPER OFF AND/OR EXIT EAST. THE WEAK FRONTAL BOUNDARY ASSOCIATED WITH THE TROF WILL NOT ACTUALLY CROSS THE REGION TONIGHT. THIS WILL KEEP MOIST AIR IN PLACE...AND DEPENDING ON RAINFALL TODAY COULD RESULT IN FOG TONIGHT. TEMPERATURES WILL BE A BIT COOLER TODAY THAN THEY WERE YESTERDAY...HOWEVER INCREASED MOISTURE WILL MAKE IT FEEL MORE MUGGY. HIGHS SHOULD BE IN THE LOWER 80S NORTH OF THE THRU-WAY...BUT MAY STAY IN THE UPPER 70S IN THE SOUTHERN TIER WHERE CLOUDS AND SHOWERS SHOULD LIMIT TEMPERATURES A BIT. FOR TONIGHT...LOWS WILL RANGE FROM THE LOWER 60S IN THE SOUTHERN TIER...TO AROUND 70 IN THE BUFFALO/ROCHESTER METRO AREAS. && .SHORT TERM /MONDAY THROUGH WEDNESDAY/... DURING THE COURSE OF MONDAY...THE AXIS OF A WEAK UPPER LEVEL TROUGH DRAPED FROM THE NEW ENGLAND COAST TO THE MID ATLANTIC STATES WILL SLIDE OUT TO SEA...ALLOWING THE LEADING EDGE OF BROAD/FLAT UPPER RIDGING TO EDGE NORTHEAST INTO THE LOWER LAKES. MEANWHILE AT THE SURFACE...LINGERING WEAK TROUGHINESS ACROSS THE LOWER LAKES AT THE START OF THE DAY WILL ALSO SLIDE EASTWARD...GIVING WAY TO MODEST LOW LEVEL RIDGING DURING THE AFTERNOON. GIVEN THESE DEVELOPMENTS...EXPECT THAT MONDAY SHOULD LARGELY BE ANOTHER DRY AND HOT/HUMID DAY...WITH 850 MB TEMPS OF +16C/+17C AGAIN SUPPORTING WIDESPREAD HIGHS IN THE UPPER 80S/LOWER 90S GIVEN WHAT SHOULD BE A DECENT AMOUNT OF SUNSHINE. WHILE BOTH THE GFS AND ECMWF BOTH SPIT OUT SOME LIGHT QPF ACROSS THE AREA PRIOR TO THE DEPARTURE OF THE LOW LEVEL TROUGH...BELIEVE THAT THIS IS OVERDONE GIVEN ONLY WEAK LINGERING FORCING AND FAIRLY WARM MID LEVEL TEMPS...WHICH SHOULD HELP TO KEEP ANY PRECIP ISOLATED IN COVERAGE AT BEST. HAVE THEREFORE KEPT POPS AT THE VERY LOW END OF THE SLIGHT CHANCE RANGE OR BELOW ON MONDAY. MONDAY NIGHT...BROAD/FLAT UPPER RIDGING WILL REMAIN INTACT ACROSS MUCH OF THE AREA...WHILE A SLOW MOVING COLD FRONTAL BOUNDARY OVER CENTRAL ONTARIO PROVINCE SAGS SOUTHWARD INTO THE UPPER LAKES AND SOUTHERN ONTARIO. WHILE I CANNOT TOTALLY RULE OUT SOME ASSOCIATED ISOLATED CONVECTION SNEAKING INTO THE SAINT LAWRENCE VALLEY TOWARD DAYBREAK ON TUESDAY...IT DOES APPEAR THAT THE FRONT WILL REMAIN FAR ENOUGH TO OUR NORTH AND THAT WE WILL REMAIN CAPPED ENOUGH FOR MAINLY DRY WEATHER TO CONTINUE AREAWIDE. WITH NO AIRMASS CHANGE AND AN INCREASING SOUTHWESTERLY LOW LEVEL FLOW EXPECTED WITH TIME IN RESPONSE TO THE APPROACHING FRONT...EXPECT DOWNRIGHT SULTRY TEMPERATURES WITH OVERNIGHT LOWS RANGING FROM THE MID AND UPPER 60S ACROSS INTERIOR SECTIONS...TO THE LOWER 70S ACROSS THE LAKE PLAINS. ON TUESDAY...THE AFOREMENTIONED FRONT WILL CONTINUE TO SLOWLY SAG SOUTH TOWARD OUR REGION...WITH NOTABLE TIMING DIFFERENCES SEEN AMONGST THE VARIOUS GUIDANCE PACKAGES. THE 00Z NAM IS AN EXTREMELY FAST OUTLIER THAT BRINGS THE FRONT COMPLETELY THROUGH THE AREA BY THE END OF THE DAY...WHICH SEEMS HIGHLY UNLIKELY GIVEN ITS NEAR-PARALLEL ORIENTATION TO THE UPPER LEVEL FLOW...NOT TO MENTION THE PROPENSITY FOR SUCH BOUNDARIES TO GET HUNG UP ACROSS THE LOWER LAKES AT THIS TIME OF YEAR. FOR THIS REASON...HAVE COMPLETELY DISREGARDED THIS SOLUTION. OF THE REMAINING GUIDANCE...THE GFS REMAINS A BIT ON THE FASTER SIDE THOUGH NOT AS FAST AS ITS PREVIOUS RUNS...BRINGING THE BOUNDARY INTO NORTHERN NEW YORK/LAKE ONTARIO BY THE END OF THE DAY...WHICH IS CLOSE ENOUGH TO GENERATE SOME CONVECTION ACROSS BOTH THE NORTH COUNTRY AND NIAGARA/ORLEANS COUNTIES. MEANWHILE...THE VERY CONSISTENT ECMWF REMAINS A TOUCH SLOWER THAN THE GFS AND ONLY BRINGS A RISK OF CONVECTION INTO THE NORTH COUNTRY...WITH THE 00Z GEM GLOBAL A BIT SLOWER STILL. AT THIS JUNCTURE...FEEL A COMPROMISE BETWEEN THE GFS/ECMWF REPRESENTS THE MOST PLAUSIBLE SCENARIO...WHICH WOULD BRING AT LEAST A LOW TO MODEST CHANCE OF CONVECTION TO LAKE ONTARIO AND THE NORTH COUNTRY BY LATE IN THE DAY. FURTHER TO THE SOUTH...CONDITIONS SHOULD REMAIN DRY THROUGH THE DAY ON TUESDAY...THANKS TO BOTH GREATER DISTANCE FROM THE FRONT AND STRONG MID LEVEL CAPPING...AS EVEN HOTTER AIR RIDES EAST ALONG THE PERIPHERY OF THE MAIN UPPER LEVEL RIDGE. A CONSENSUS OF THE GFS/GEM/ECMWF SUPPORTS 850 MB TEMPS RISING TO THE +20/+21C RANGE AREAWIDE DURING THE COURSE OF TUESDAY...AND THIS COUPLED WITH GOOD MIXING AND A DECENT AMOUNT OF SUN WILL LIKELY RESULT IN A REAL SCORCHER OF A DAY SOUTH OF LAKE ONTARIO. AT THIS POINT...WIDESPREAD HIGHS IN THE LOWER TO MID 90S APPEAR TO BE A SOLID BET...WITH UPPER 90S NOT AT ALL OUT OF THE QUESTION FOR THE NORMAL HOT SPOTS IN INTERIOR PORTIONS OF OUR CWA. COUPLED WITH DEWPOINTS IN THE MID TO UPPER 60S...SOME LOCATIONS SOUTH OF LAKE ONTARIO COULD SEE APPARENT TEMPERATURES REACHING THE 100 DEGREE MARK TUESDAY AFTERNOON...WHICH WOULD NECESSITATE THE ISSUANCE OF A HEAT ADVISORY. AS IT REMAINS FAR TOO EARLY FOR THAT...FOR NOW WILL JUST MENTION THIS POTENTIAL IN THE HWO. EAST OF LAKE ONTARIO...SOMEWHAT GREATER AMOUNTS OF CLOUD COVER WILL LIKELY HELP KEEP TEMPS A LITTLE COOLER...THOUGH IT SHOULD STILL BE UNCOMFORTABLY HOT EVEN THERE WITH HIGHS IN THE UPPER 80S TO LOWER 90S. TUESDAY NIGHT AND WEDNESDAY...THE COLD FRONT WILL SLOWLY SAG SOUTH ACROSS THE REGION...BRINGING A RISK OF CONVECTION TO THE ENTIRE CWA...ALONG WITH THE POTENTIAL FOR LOCALLY HEAVY RAINFALL GIVEN PRECIPITABLE WATER VALUES IN THE VICINITY OF AROUND 2 INCHES. AT THIS JUNCTURE...THE TIMING OF THIS BOUNDARY REMAINS AN ISSUE WITH THE GFS REMAINING THE FASTEST...THE CANADIAN THE SLOWEST...AND THE ECMWF IN THE MIDDLE...WITH FROPA TIMES RANGING BETWEEN EARLY TO MID WEDNESDAY MORNING AND WEDNESDAY AFTERNOON. GIVEN THAT THIS FRONT APPEARS TO BE ANAFRONTAL WITH MOST OF ITS PRECIP FALLING BEHIND THE ACTUAL SURFACE BOUNDARY...THIS MEANS THAT ANY ASSOCIATED CONVECTION COULD END AS EARLY AS SOMETIME WEDNESDAY MORNING...OR AS LATE AS THE END OF THE DAY WEDNESDAY. GIVEN THE CONTINUED UNCERTAINTIES IN TIMING AND THE AFOREMENTIONED NEAR-PARALLEL ORIENTATION OF THE FRONT TO THE UPPER FLOW...FEEL IT IS BEST TO SLOW DOWN THE TIMING OF THIS FRONT AND ITS ASSOCIATED CONVECTION A BIT FROM THE PREVIOUS FORECAST...FAVORING A COMPROMISE SOLUTION ALONG THE LINES OF THE ECMWF. AS A RESULT...CHANCES FOR CONVECTION WILL BE IN PLACE FROM TUESDAY NIGHT THROUGH WEDNESDAY MORNING ACROSS THE ENTIRE AREA...BEFORE DIMINISHING FROM NORTH TO SOUTH DURING THE COURSE OF WEDNESDAY AFTERNOON. TEMPERATURE-WISE... EXPECT ANOTHER SULTRY NIGHT IN ADVANCE OF THE FRONT TUESDAY NIGHT WITH LOWS AGAIN RANGING FROM THE UPPER 60S TO LOWER 70S...FOLLOWED BY SOMEWHAT COOLER HIGHS IN THE UPPER 70S TO MID 80S ON WEDNESDAY GIVEN THE PASSAGE OF THE FRONT AND ITS ASSOCIATED CLOUD COVER/PRECIP. && .LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/... SIMPLY PUT...SPRAWLING CANADIAN HIGH PRESSURE WILL BUILD SOUTHEAST ACROSS THE GREAT LAKES AND NORTHEAST DURING THIS PERIOD...BRINGING A RETURN TO DRY WEATHER ALONG WITH A COOLER AND NOTICEABLY LESS HUMID AIRMASS. IN TERMS OF ACTUAL TEMPERATURES...EXPECT DAILY HIGHS TO FALL BACK INTO THE MID 70S TO LOWER 80S FOR BOTH THURSDAY AND FRIDAY...BEFORE WARMING BACK INTO THE LOWER TO MID 80S ON SATURDAY AS WARMING COMMENCES ALOFT. MEANWHILE...NIGHTTIME LOWS WILL RANGE IN THE MID 50S TO LOWER 60S ALL THREE NIGHTS. HUMIDITY LEVELS WILL ALSO BE MUCH MORE COMFORTABLE...WITH DEWPOINTS REMAINING IN THE MID TO UPPER 50S DURING THE BULK OF THE PERIOD. && .AVIATION /08Z SUNDAY THROUGH THURSDAY/... THE THREAT FOR SHOWERS AND THUNDERSTORMS WILL INCREASE FROM SW TO NE BETWEEN 06Z AND 15Z AS A WEAK LOW LEVEL JET KEYS THE ADVANCE OF MOIST AIR. RADAR SUGGESTS THESE STORMS WILL BE SCATTERED IN NATURE...NOT IMPACTING ALL TAF SITES. THERE IS A MINIMAL CHANCE FOR FOG AT BUF/IAG/ROC/ART...BUT AT JHW THERE APPEARS A GOOD CHANCE FOR A SHOWER SHORTLY AFTER 06Z...WHICH MAY LEAD TO FOG AND LOW CLOUDS IFR OR LOWER. BEHIND THIS INITIAL AREA OF SHOWERS AND THUNDERSTORMS WILL BE ANOTHER OPPORTUNITY FOR CONVECTION WITH AN APPROACHING SHORTWAVE THIS AFTERNOON. LAKE SHADOWING WILL DIMINISH THE POTENTIAL AT BUF/IAG/ART...THOUGH THE LAKES ARE WARM ENOUGH THAT THUNDERSTORMS CANNOT COMPLETELY BE RULED OUT AT ANY TAF LOCATION. THIS SAID...THE BEST CHANCE FOR THUNDERSTORMS WILL BE OUT AHEAD OF THIS SHORTWAVE AT JHW/ROC EARLY THIS AFTERNOON. EXPECT A GENERAL CLEARING TREND FROM WEST TO EAST LATE THIS AFTERNOON AND EVENING. THIS SHOULD RESULT IN MAINLY VFR CONDITIONS...BUT THERE WILL BE AN INCREASING CHANCE FOR FOG OVERNIGHT. THE COMBINATION OF LIGHT WINDS AND LINGERING BOUNDARY LAYER MOISTURE MAY RESULT IN FAIRLY WIDESPREAD IFR OR LOWER CONDITIONS LATE TONIGHT...ESPECIALLY IF SKIES CLEAR OUT. OUTLOOK... MONDAY AND TUESDAY...MAINLY VFR. TUESDAY NIGHT...AREAS OF MVFR IN SCATTERED -SHRA/-TSRA. WEDNESDAY...BECOMING VFR. THURSDAY...VFR. && .MARINE... HIGH PRESSURE WILL REMAIN ANCHORED ALONG THE MID ATLANTIC COAST THROUGH EARLY NEXT WEEK. MEANWHILE A WEAK TROUGH WILL APPROACH THE LOWER LAKES TODAY AND ALLOW SOUTHWEST WINDS TO INCREASE SOMEWHAT TO THE 10-15 KNOT RANGE...WITH THE STRONGEST WINDS ON LAKE ERIE. EXPECT CONDITIONS TO REMAIN BELOW SMALL CRAFT CRITERIA...BUT WAVES MAY GET A LITTLE CHOPPY ON LAKE ERIE. A RIDGE OF HIGH PRESSURE WILL NOSE INTO THE LOWER LAKES MONDAY WITH RELATIVELY LIGHT WINDS. SOUTHWEST WINDS WILL PICK UP AGAIN TUESDAY AHEAD OF A STRONGER COLD FRONT...ESPECIALLY ON LAKE ERIE WHERE CONDITIONS MAY APPROACH SMALL CRAFT ADVISORY CRITERIA. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...NONE. MARINE...NONE. && $$ SYNOPSIS...APFFEL NEAR TERM...APFFEL SHORT TERM...JJR LONG TERM...JJR AVIATION...APFFEL MARINE...APFFEL/JJR
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1126 PM CDT SAT JUL 14 2012 .AVIATION... NOT MUCH CHANGE FROM EARLIER THINKING. DO EXPECT SOME SCT SHRA/TSTM REDEVELOPMENT LATER TONIGHT AND TOWARD MORNING. THOUGH IT COULD BE ANYWHERE...MOST FAVORABLE LOCATIONS WOULD BE CLOSER TO THE COAST AND UP TOWARD THE LAKE LIVINGSTON AREA CLOSER TO THE UPPER CIRCULATION AND WHERE THE MORE FAVORABLE JET STRUCTURE WILL BE. BEST COURSE OF ACTION WILL PROBABLY BE TO USE VCSH/VCTS`S AND AMEND WHEN NECESSARY VERSUS CLUTTER TAFS WITH TEMPOS ETC. PRECIP SHOULD EXPAND IN COVERAGE WITH MID/LATE MORNING HEATING AGAIN SUNDAY. PRECIP SHOULD TAKER OFF FROM SOUTH TO NORTH DURING THE LATE AFTN AND EARLY EVNG HOURS. 47 && .PREV DISCUSSION... /ISSUED 916 PM CDT SAT JUL 14 2012/ SHOWERS AND THUNDERSTORMS HAVE DIMINISHED QUICKLY YET AGAIN THIS EVENING. UPDATED GRIDS FOR OBSERVED CONDITIONS IN THE VERY SHORT RANGE. LOW LEVEL CIRCULATION APPARENT IN RAP13...PROFILER WINDS...VWP WINDS AND SATELLITE LOOPS NEAR LONGVIEW (KGGG). AT 700MB PROFILER AND VWP WINDS SUGGEST TROUGH IS NEAR OR JUST OFF THE SE TEXAS COAST AND CURVE BACK TO THE LOW. PWAT VALUES DO APPEAR SLIGHTLY REDUCED FROM PREVIOUS EVENINGS WITH 00Z RAOB VALUES RANGING FROM 1.8 TO NEAR 2 INCHES. BLENDED TPW IMAGERY FOR THE CWA ARE AROUND 1.88 INCH SO STILL PLENTY MOISTURE RICH BUT A TAD LOWER. SFC MESO BOUNDARIES GALORE THIS EVENING FROM CONVECTIVE OUTFLOWS AND A LATE DEVELOPING SEA BREEZE. ONE BOUNDARY FROM NORTH OF COLLEGE STATION TO CALDWELL ON SOUTHWESTWARD. ANOTHER OVER COLORADO COUNTY..SEVERAL FROM CONVECTION OCCURRING NORTH OF CWA AND OLD SEA BREEZE BOUNDARY FROM LIBERTY TO KHOU TO KBYY. HRRR AND TX TECH WRF REFLECTIVITY FORECASTS ARE FOR GENERALLY QUIET NIGHT WITH SOME DEVELOPMENT TOWARDS SUNRISE BUT FEEL WITH MULTITUDE OF BOUNDARIES AND SLOWLY RETREATING TROUGH/LOW SOME ISOLATED TO SCATTERED CONVECTION POSSIBLE A COUPLE OF HOURS PRIOR TO SUNRISE MAINLY NEAR COAST AND NORTH OF A LINE FROM NORMANGEE TO LIVINGSTON NEARER TO 850-700MB LOW. THIS IS HANDLED WELL IN OUR CURRENT FORECAST LATER TONIGHT AND TOMORROW MORNING SO NO CHANGE NECESSARY. STILL A POSSIBILITY FOR SOME ISOLATED HEAVY RAINS ON SUNDAY SO MENTION OF LOCALLY HEAVY RAINS IN ZFP/GRIDS REMAINS A GOOD IDEA. 04 && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 73 88 73 92 74 / 20 50 20 30 20 HOUSTON (IAH) 74 89 74 91 75 / 20 50 30 40 20 GALVESTON (GLS) 80 88 82 90 81 / 30 50 40 40 30 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$
AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
853 AM PDT SUN JUL 15 2012 .SYNOPSIS... AN UPPER-LEVEL TROUGH STRENGTHENING ALONG THE WEST COAST...WILL BRING STRONGER ONSHORE FLOW...GRADUAL INLAND DRYING...AND A DEEPER MARINE LAYER THROUGH TUESDAY. IT WILL BE COOLER...WITH MARINE CLOUDS EXTENDING FARTHER INTO THE VALLEYS EACH MORNING. LATER NEXT WEEK... HIGH PRESSURE OVER THE MIDDLE OF THE COUNTRY WILL REBUILD WESTWARD...BRINGING WARMER DAYS AND SOME INCREASE IN MONSOONAL MOISTURE. THE ADDED MOISTURE WILL LIKELY RESULT IN SOME AFTERNOON CLOUDS OVER THE MOUNTAINS...AND PERHAPS SOME RENEWED CHANCE OF THUNDERSTORMS OVER THE WEEKEND OR EARLY NEXT WEEK. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... && VISIBLE SATELLITE IMAGERY EARLY THIS MORNING SHOWED EXTENSIVE MARINE STRATUS OFFSHORE AND EXTENDING WELL INTO THE VALLEYS. BASED ON THE 12Z MIRAMAR SOUNDING...THE LAYER HAD DEEPENED TO AROUND 2000 FT AT 12Z AND WAS CAPPED BY A STRONG 10 DEGREE C INVERSION. SFC PRESSURE GRADIENTS REMAINED WEAK...BUT WERE ONSHORE GENERALLY 2-4 MBS TO THE DESERTS. WATER VAPOR IMAGERY THROUGH 15Z SHOWS THE UPPER-LEVEL TROUGH ALONG THE WEST COAST WAS IN FULL DEEPENING MODE WHICH WILL DEFINE OUR WEATHER FOR THE NEXT SEVERAL DAYS. LOWER SFC PRESSURES OVER THE INTERIOR...STRONGER ONSHORE FLOW...AND A DEEPENING MARINE LAYER WILL BRING COOLER DAYS AND SOME NOCTURNAL CLOUDS/FOG WELL INTO THE VALLEYS THROUGH TUE. INLAND...BETTER ONSHORE FLOW WILL BRING DRYING WITH LOWER DEWPOINTS INTO THE DESERTS. FOR TODAY...SOME RESIDUAL BOUNDARY LAYER MOISTURE WILL LIKELY RESULT IN SOME CU BUILD-UPS OVER THE MOUNTAINS. AN ISOLATED SHOWER IS NOT OUT OF THE QUESTION EITHER BASED ON AVBL SFC DEWPOINTS IN THE MTNS/ DESERTS AND THE HIGHER RESOLUTION HRRR MODEL. FOR NOW...THE POP LOOKS TOO LOW FOR MENTION IN THE ZONES. ALONG THE COAST...THE STRONG INVERSION MAY CONTRIBUTE TO A LATE BREAK-UP OF THE STRATUS...BUT THE THICKNESS OF THE CLOUD DECK BASED ON SFC OBSERVATIONS SHOW IT SHOULD BREAK...EVEN AT MOST BEACHES...WITH AT LEAST A FEW HOURS OF SUN TODAY. ELSEWHERE... SUNNY...WITH TEMPS A FEW DEGREES LOWER THAN YESTERDAY W OF THE MTNS...BUT A FEW DEGREES HIGHER IN THE LOWER DESERTS DUE TO LOWER HUMIDITY. WEDNESDAY SHOULD BE THE TRANSITION DAY WITH THE MARINE LAYER BEGINNING TO DECREASE IN DEPTH AND SLOW INLAND WARMING AS THE TROUGH OF LOW PRESSURE NEAR THE WEST COAST BEGINS TO WEAKEN AND HIGH PRESSURE TO THE EAST BEGINS TO STRENGTHEN. FOR WED NIGHT/THU...SOME MID/HIGH LEVEL MOISTURE FROM THE REMNANTS OF HURRICANE FABIO WILL BE DRAWN NORTHWARD ACROSS CALIFORNIA...MAINLY NORTH OF ORANGE COUNTY. FOR SOUTHWEST CALIFORNIA...THE MAIN IMPACT WOULD APPEAR TO BE SOME INCREASE IN MID/HIGH LEVEL CLOUDS. CHANCES FOR SPRINKLES/SHWRS THIS FAR SOUTH LOOK MINIMAL. THE HIGH CLOUDS MAY CONTRIBUTE TO A COLORFUL SUNSET THOUGH...FOR THOSE AREAS UNOBSCURED BY LOWER MARINE CLOUDS. WARMER INLAND FOR THE LATTER HALF OF THE WEEK AS HIGH PRESSURE BROADENS ACROSS THE WESTERN HALF OF THE COUNTRY. THIS WILL TURN UPPER-LEVEL WINDS AGAIN MORE SOUTHEASTERLY...SOME MONSOONAL MOISTURE MAY INCREASE OVER SW CA...BRINGING PERIODS OF MID/HIGH CLOUDS AND AFTERNOON CU OVER THE MOUNTAINS. POPS HAVE BEEN BUMPED UP OVER CLIMATOLOGY TO REFLECT AN INCREASED CHANCE OF CONVECTIVE SHOWERS BUT CONFIDENCE NOT HIGH ENOUGH TO INCLUDE IN THE CURRENT FORECAST. TEMPS SHOULD BE NEAR MID-SUMMER AVERAGES. && .AVIATION... 151545Z...COAST/VALLEYS...STRATUS WILL CLEAR MOST VALLEYS THROUGH 17Z AND COASTAL AREAS BETWEEN 16Z AND 18Z EXCEPT ALONG THE BEACHES WHERE PATCHY BKN CLOUDS WILL LINGER THROUGH THE AFTERNOON. STRATUS WILL RETURN TO COASTAL AIRPORTS BETWEEN 00Z AND 04Z AND THE VALLEYS BETWEEN 05Z AND 09Z WITH LITTLE CHANGE TO BASES...1000-1500 FT MSL AND TOPS TO 2000 FT MSL. LOCAL VIS BELOW 3 MI WILL OCCUR IN THE VALLEYS LATE TONIGHT. MTNS/DESERTS...SCATTERED CUMULUS WITH BASES 8000-9000 FT MSL ARE EXPECTED OVER THE MTNS AND SOME DESERT AREAS THROUGH 02Z. OTHERWISE...MOSTLY CLEAR WITH UNRESTRICTED VIS THROUGH MONDAY. .MARINE... HURRICANE FABIO...CURRENTLY IN OUR SWELL WINDOW NEAR 17N/117W WILL BRING INCREASING SOUTH SWELL BY MONDAY NIGHT OR TUESDAY...GENERALLY 4 FEET IN THE COASTAL WATERS. THIS WILL BE A BIT HIGHER THAN WITH THE LAST 2 HURRICANES DUE TO THE SLOWER MOVEMENT OF FABIO AND HENCE A LONGER DURATION OF THE SWELL GENERATION...DESPITE FABIO BEING LESS STRONG. THIS WILL BRING ANOTHER ROUND OF ABOVE NORMAL SURF AND RIP CURRENTS ON MAINLY S/SW FACING BEACHES LATE MONDAY NIGHT THROUGH WED...THEN GRADUALLY DIMINISHING THROUGH THU. && .SGX WATCHES/WARNINGS/ADVISORIES... CA...NONE. PZ...NONE. && $$ PUBLIC...JAD AVIATION/MARINE...MAXWELL
AREA FORECAST DISCUSSION...Updated
NWS TALLAHASSEE FL
700 AM EDT Sun Jul 15 2012 Updated Aviation Discussion. .NEAR TERM [Through Today]... A rather amplified and complex upper level pattern is depicted this morning by the 05z RAP analysis. Two shortwave troughs across the Pacific Northwest and the Upper Midwest are complimented by two ridges across the Plains states and the Southeast states. Pinched off from the easternmost trough is a weak closed low centered over the Southern Plains. Finally, a TUTT draped across the western Caribbean, northeast into the western Atlantic, continues its slow westward progression. For this afternoon, subsidence provided by the southeastern U.S. ridge will provide our local area with slightly drier conditions. That being said, precipitable water levels are expected to remain at or slightly above climatological normals for this time of year. With no large scale support for ascent expected, the local seabreeze fronts will dominate this afternoon`s weather pattern. With slightly more easterly flow regime expected today, a slightly modified regime 2 is expected. This regime would favor the Panhandle Seabreeze Front and the East Coast Seabreeze Front. Thus PoPs are highest across the Florida Panhandle, and later across our eastern counties in Georgia and Florida. With respect to the threat for severe weather, no severe weather is expected across our Florida counties this afternoon. Lower than normal instability coupled with several other poor to marginal thermodynamic variables will be the limiting factors here. There does exist a slight chance for severe storms across our Georgia and Alabama counties today, with a few caveats. Drier mid-level air will increase the theta-e differences between the middle and lower troposphere. This coupled with steep low level lapse rates will increase the threat for severe downbursts. However, the dry air may also be the limiting factor in storm development. The best case scenario for severe storm development across Georgia would be late in the afternoon/early evening when the East Coast Seabreeze enters the primed atmosphere. The same story holds true for southeast Alabama, with a different forcing mechanism. Any storms that for across Alabama will likely be due to boundary interactions from the Panhandle Seabreeze. A late afternoon/early evening threat timeline is expected across Alabama as well. Waterspouts will be possible again today, primarily along eastward facing Big Bend beaches due to the more easterly wind component. The threat should diminish by the afternoon with the diminishing wind enhancement behind yesterday`s East Coast Seabreeze Front. && .SHORT TERM [Tonight Through Tuesday]... Seabreeze circulations will continue to influence the precipitation pattern through the remainder of the short term. However, beginning Monday, the aforementioned TUTT will move southwest into our eastern forecast area. This will especially enhance PoPs across north Florida, east of the Apalachicola River. On Tuesday, the trough will overspread our entire forecast area enhancing PoPs area wide. Temperatures will hold near climatological averages in the lower 90s each afternoon, and the lower 70s each night. && .LONG TERM [Tuesday Night through Sunday]... Very little change to the extended fcst this cycle as the latest 00 UTC GFS and ECMWF have remained in fairly good agreement with a Synoptic pattern dominated by a TUTT Low which will gradually open up into an Upper Level Trof. This should further increase fcst confidence in above Climo Pops and near Climo Max Temps through much of the period. Despite the fairly disturbed pattern, the MEX High Temps appeared too high (Mid 90s in many areas away from the coast) for the expected levels of cloud cover and rain chances, so used a 2-1 Blend of the lower and more realistic looking HPC and MOS Guidance grids. The Euro (and GFS to some extent) do both show some potential for a brief break in this pattern on Friday, with possible Upper Level Ridging moving in from the east, before the mean Trof builds back southward over the weekend, bringing a return to higher rain chances. && .AVIATION... The Hi-Res models turned out to be correct, as VFR conditions prevailed through the night and early morning at all of the terminals. For the remainder of today, VFR conditions should prevail with slightly lower PoPs than yesterday...especially further to the north. Did upgrade ECP and VLD to convective tempos, with VCTS at TLH, and just VFR the rest of the day at ABY and DHN. && .MARINE... Winds and seas will remain below headline criteria for the next several days as the subtropical ridge keeps a firm hold on the region. Enhancements nearing SCEC criteria are possible this morning and tomorrow morning along the East Coast Seabreeze Front. Flow will shift more southerly by Tuesday, effectively ending the East Coast Seabreeze enhancements. && .FIRE WEATHER... Still no fire weather concerns in sight over the foreseeable future across the Tri-State area, as ample low-level moisture will keep afternoon relative humidities fairly high through the period. && .TAE WATCHES/WARNINGS/ADVISORIES... FL...None. GA...None. AL...None. MARINE...None. && $$ NEAR TERM...Harrigan SHORT TERM...Harrigan LONG TERM...Gould AVIATION...Gould MARINE...Harrigan FIRE WEATHER...Gould
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
1015 AM EDT SUN JUL 15 2012 .SYNOPSIS... ATLANTIC HIGH PRESSURE WILL EXTEND ACROSS THE REGION AS A WEAK TROUGH OF LOW PRESSURE DEVELOPS INLAND. A COLD FRONT WILL APPROACH FROM THE NORTH LATE IN THE WEEK AND LIKELY STALL OUT THROUGH THE WEEKEND LEADING TO UNSETTLED CONDITIONS. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... LATE MORNING WATER VAPOR IMAGERY SHOWS A WELL DEFINED TUTT LOW SPINNING IN THE VICINITY OF 31.3N/-76.9W. DRY AIR ALONG ITS WESTERN PERIPHERY HAS INFILTRATED SOUTHEAST SOUTH CAROLINA AND SOUTHEAST GEORGIA WITH PWATS MEASURED ON THE 15/12Z CHS RAOB WELL BELOW 2 INCHES. THE ATMOSPHERE REMAINS TROPICAL DESPITE THE PRESENCE OF MID-LEVEL DRY AIR WITH A DEEP/MOIST FLOW FROM OF THE ATLANTIC HELPING TO ADVECT RICH LOW-LEVEL THETA AIR INTO THE REGION. CONVECTIVE TEMPERATURES ARE JUST ABOUT TO BE SURPASSED PER REGIONAL RAP BUFR SOUNDINGS AND IN FACT SHOWER ACTIVITY IS ALREADY BEGINNING TO BLOSSOM AS EXPECTED ALONG THE COAST. CONVECTION WILL CONTINUE TO EXPAND OVER THE NEXT SEVERAL HOURS WITH SCATTERED SHOWERS/TSTMS EXPECTED TO CONCENTRATE INLAND AHEAD OF AN ILL-DEFINED PURE SEA BREEZE CIRCULATION OVER THE NEXT SEVERAL HOURS. OPTED TO MODIFY THE CURRENT POP REGIME SLIGHTLY TO HIGHLIGHT A LARGER AREA OF CHANCE POPS OF 30-40 PERCENT. CONVECTION SHOULD GRADUALLY END FROM EAST-WEST LATER THIS AFTERNOON IN THE WAKE OF THE SEA BREEZE. NUDGED HIGHS DOWN JUST A DEGREE OR TWO FOR MOST AREAS. HIGHS WILL RANGE FROM THE LOWER 90S INLAND TO THE MID 80S AT THE BEACHES. THE RISK FOR A FEW STRONG TO SEVERE TSTMS WILL BE A BIT HIGHER COMPARED TO THE PAST SEVERAL DAYS WITH SLIGHTLY DRIER MID-LEVEL AIR NOW IN PLACE. THERMODYNAMIC PARAMETERS ON THE MODIFIED 15/12Z CHS RAOB DEPICTED DCAPES NEAR 1400 J/KG WITH A WINDEX NEAR 60 KT...WHICH IS SUPPORTIVE OF AN ENHANCED WET MICROBURST ENVIRONMENT. ATTM THINK THE RISK IS LIKELY TOO LOW TO JUSTIFY A MENTION IN THE HAZARDOUS WEATHER OUTLOOK...BUT ONE OR TWO SEVERE TSTM WARNINGS CAN NOT BE COMPLETELY RULED OUT THROUGH MID-LATE AFTERNOON...MAINLY INLAND. && .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/... THE CONVECTION WILL DIMINISH OVER LAND WITH THE SUNSET...SO MOST PLACES WILL BE DRY DURING SUNDAY EVENING. ONCE AGAIN...SCATTERED SHOWERS SHOULD AGAIN REDEVELOP OVER THE COASTAL WATERS AND MOVE TOWARD THE COAST DURING THE LATE NIGHT HOURS...BUT MOST ACTIVITY SHOULD REMAIN OFFSHORE. A MID/UPPER-LEVEL LOW PRESSURE SYSTEM WILL MOVE ONSHORE MONDAY AND THEN SHIFT SOUTHWEST OF THE AREA TUESDAY AND WEDNESDAY. MAINLY AFTERNOON/EVENING SHOWERS AND THUNDERSTORMS EACH DAY WITH PROBABLY THE BETTER COVERAGE COMING TUESDAY AND WEDNESDAY AS A SURFACE TROUGH OF LOW PRESSURE DEVELOPS INLAND. TEMPERATURES GENERALLY NEAR NORMAL MONDAY...THEN SLIGHTLY ABOVE NORMAL TUESDAY AND WEDNESDAY. && .LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/... MID/UPPER-LEVEL HIGH PRESSURE OVER THE ATLANTIC TO EDGE WESTWARD AND EXERT MORE INFLUENCE ON THE AREA THURSDAY INTO FRIDAY BEFORE WEAKENING TOWARD THE END OF THE WEEK AS A TROUGH SHIFTS OFFSHORE TO THE NORTH. THIS FEATURE WILL PUSH A COLD FRONT TOWARD THE AREA ALTHOUGH CLIMATOLOGY WOULD SUGGEST IT WILL REMAIN TO THE NORTH. FAVORABLE SYNOPTIC LIFT AND DEEPER MOISTURE ALONG WITH THE SURFACE FRONT AND AREAS OF LOW PRESSURE ALONG IT WILL CREATE MORE FAVORABLE CONDITIONS FOR SHOWERS AND THUNDERSTORMS FRIDAY THROUGH THE WEEKEND. PRECIPITABLE WATER VALUES OF AT LEAST 2 INCHES WILL SUPPORT THE THREAT FOR LOCALIZED HEAVY RAINFALL. TEMPERATURES TO START OUT ABOVE NORMAL BEFORE FALLING BACK CLOSER TO NORMAL LATER IN THE WEEK AND OVER THE WEEKEND WITH INCREASED CLOUDS/RAIN. && .AVIATION /14Z SUNDAY THROUGH THURSDAY/... VFR FOR THE NEXT 24 HOURS. ISOLATED SHOWERS AND POSSIBLY A TSTM COULD IMPACT KCHS/KSAV AT JUST ABOUT ANY TIME THROUGH MID- AFTERNOON...BUT ANY IMPACT DURATIONS SHOULD REMAIN LESS THAN 5-10 MINUTES AT BEST. WILL NOT HIGHLIGHT ANY MENTION OF SHRA OR TSRA AT EITHER TERMINAL JUST YET BECAUSE OF THIS. LOW CHANCE FOR SHALLOW GROUND FOG IMPACTING THE TERMINALS EARLY MONDAY. EXTENDED AVIATION OUTLOOK...THERE ARE NO CONCERNS OF GREATER THAN 30 PERCENT CONFIDENCE. && .MARINE... WINDS WILL CONTINUE TO BE LIGHT TODAY AND TONIGHT IN THE VICINITY OF THE SURFACE RIDGE. SUSTAINED WINDS WILL BE LESS THAN 15 KNOTS. THERE MAY BE A SMALL SWELL OF 2 FEET OR SO IN THE WATERS DUE TO THE LONG FETCH OF SOUTHEASTERLIES EXTENDING WELL OUT INTO THE ATLANTIC...BUT THE SURFACE WINDS WILL BE TOO LIGHT TOO ADD MUCH WIND WAVE INTO THE EQUATION...SO 2 TO 3 FEET NEARSHORE AND 3 TO 4 FEET OFFSHORE LOOK GOOD TODAY. MONDAY THROUGH FRIDAY...ATLANTIC HIGH PRESSURE TO REMAIN IN CONTROL THIS PERIOD WITH A WEAK TROPICAL WAVE OF LOW PRESSURE LIKELY AFFECTING THE AREA MONDAY. THEREAFTER...A SOUTH/SOUTHWESTERLY FLOW WILL DOMINATE AS A TROUGH OF LOW PRESSURE SETS UP INLAND AND ATLANTIC HIGH PRESSURE STRENGTHENS OFFSHORE. CONDITIONS SHOULD REMAIN BELOW ADVISORY LEVELS THROUGH THE PERIOD ALTHOUGH WINDS/SEAS WILL BE ON THE INCREASE STARTING MID WEEK AS THE PRESSURE GRADIENT STRENGTHENS BETWEEN THESE TWO SYSTEMS. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...NONE. && $$ SYNOPSIS... NEAR TERM... SHORT TERM...ALSHEIMER/RJB LONG TERM...RJB AVIATION... MARINE...
AREA FORECAST DISCUSSION
NWS JACKSON KY
1054 AM EDT SUN JUL 15 2012 .UPDATE... ISSUED AT 1054 AM EDT SUN JUL 15 2012 SHOWERS CONTINUE TO FOCUS ALONG THE NORTHWEST PORTION OF THE CWA THIS MORNING...AS A LOW LEVEL JET ALONG WITH SOME UPPER LEVEL DIVERGENCE REMAIN IN PLACE NEAR THE OHIO RIVER. SOME OF THE HEAVIER SHOWERS AND ISOLATED THUNDERSTORMS HAVE BEEN DROPPING A LOT OF RAIN IN A SHORT PERIOD OF TIME...UP TO AN INCH IN LESS THAN 30 MINUTES. FORTUNATELY...STORM MOTIONS ARE AROUND 15 KTS...HOWEVER WILL HAVE TO MONITOR AT LEAST A FEW LOCATIONS FOR REPEATED ROUNDS...WHICH COULD LEAD TO MINOR FLOODING IN LOW LYING AREAS AT A MINIMUM. HAVE INCREASED POPS UP TO CATEGORICAL GIVEN THE RADAR TRENDS. THE LATEST NAM SHOWS ACTIVITY PEAKING IN THE 15-18Z TIME FRAME AND THEN SCATTERING OUT MORE FOR THE REST OF THE AFTERNOON AS SOME MID- LEVEL CAPPING DEVELOPS. THIS IS SIMILAR TO THE 06Z RUN...SO IT MAY BE ON TO SOMETHING. THE LAST RUN OF THE SREF CONTINUES THE HIGHER POPS THROUGH 21Z AND THIS MAY ALSO BE A CONTENDER WITH ANY OUTFLOW BOUNDARY INTERACTION. FOR NOW...WILL LEAN TOWARDS THE NAM IDEA. FRESHENED UP THE REST OF THE GRIDS...MAINLY TO ALLOW FOR A FASTER DIURNAL RISE WHERE CLOUDS ARE STARTING OUT THINNER. HIGHS RANGING FROM THE LOWER 80S IN THE NORTH TO A FEW UPPER 80S IN THE SOUTHEAST LOOK ON TARGET. UPDATE ISSUED AT 700 AM EDT SUN JUL 15 2012 SHOWERS HAVE INCREASED OVER ERN KY THIS MORNING WITH A FEW RUMBLES AS WELL...LENDING SOME CREDIBILITY TO THE HRRR AND NAM12...AND HAVE BENT THE GRIDS IN THIS DIRECTION THROUGH THE REMAINDER OF THE MORNING. ALSO UPDATED SKY...ALONG WITH TEMPS AND DEW PTS TO ESTABLISH TRENDS HEADING INTO THE DAY. OTHERWISE...THE FCST IS ESSENTIALLY ON TRACK. UPDATED ZONES WILL BE ISSUED SHORTLY. && .SHORT TERM...(TODAY THROUGH MONDAY) ISSUED AT 232 AM EDT SUN JUL 15 2012 ESSENTIALLY LOOKING AT A PERSISTENCE FORECAST FOR TODAY AND TONIGHT WITH LITTLE CHANGE ANTICIPATED IN THE OVERALL. THE QUESTION REMAINS WHERE AND WHEN CONVECTION WILL INITIATE...BUT THE NEAR TERM MODELS ARE STILL PLUGGING SOME EARLY MORNING DEVELOPMENT OVER CNTRL TN AND KY SPREADING EAST THROUGH THE MORNING AND CONTINUING THROUGH THE AFTERNOON BEFORE DIMINISHING THIS EVENING FOLLOWING THE LOSS OF DAYTIME HEATING. MODELS ARE IN GENERAL AGREEMENT IN DEVELOPING SOME HEALTHY INSTABILITY THIS MORNING...UPWARDS OF 3K J/KG MU CAPE AGAIN WITH CONVECTIVE TEMPS IN THE LOWER 80S AND CURRENT FCST HIGHS IN THE MID 80S. FCST PWATS CONTINUE TO RUN ABOUT 2 INCHES THROUGHOUT THE DAY...AND WITH A RIGHT ENTRANCE REGION OF A MODEST 50-60KT UPPER LEVEL JET TRAVERSING UP THE OHIO VALLEY THIS AFTERNOON...COUPLED WITH A MID LEVEL SHORT WAVE MOVING UP FROM THE TN VALLEY...CAN SEE LITTLE REASON THIS MORNING WHY WE WOULD NOT SEE SOME EFFICIENT TSTMS AGAIN LATER THIS MORNING CONTINUING THROUGH THE AFTERNOON...WITH LOCALLY HEAVY RAINFALL AGAIN THE PRIMARY CONCERN. MONDAY IS LOOKING A LITTLE MORE INTERESTING THIS MORNING WITH FCST SOUNDINGS DEPICTING A STRONGER CAP DEVELOPING BY LATE MORNING CONTINUING THROUGH THE PEAK HEATING HOURS AS THE STRONG BERMUDA HIGH IS PROGGED TO SHIFT WEST TOWARDS THE CENTRAL APPALACHIANS...WEAKENING SLIGHTLY IN THE PROCESS. DRIER...BUT WARMER MID LEVEL ADVECTION WILL EITHER SQUASH PRECIP CHANCES OR...IF THE CAP BREAKS...COULD RESULT IN SOME STRONG STORMS AGAIN DEVELOPING DURING THE AFTERNOON WITH DAMAGING WINDS POSSIBLE IN ADDITION TO THE THREAT FOR LOCALLY HEAVY RAINFALL. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 232 PM EDT SAT JUL 14 2012 THE MODELS ARE IN PRETTY GOOD AGREEMENT WITH THE GENERAL LONG WAVE PATTERN...HOWEVER THERE ARE SOME DIFFERENCES IN THE TIMING SOME OF THE SHORT WAVES LATER ON DURING THE PERIOD. ON MONDAY NIGHT...KENTUCKY WILL BE DOMINATED BY THE UPPER RIDGE WITH A MAJOR TROUGH JUST OFF THE WEST COAST. ALL THE FRONTAL ACTIVITY WILL BE WELL NORTH OF THE AREA AND THE COAL FIELDS WILL BE DOMINATED BY THE WARM...MOIST AND UNSTABLE AIR MASS. WITH TIME...AN UPPER TROUGH BEGINS TO DROP SOUTH FROM AN UPPER LOW CENTER OVER THE CANADIAN MARITIMES. THIS WILL ALLOW A COLD FRONT TO START MOVING TO THE SOUTH. BY THURSDAY MORNING...THE FRONT WILL BE OVER NORTHERN KENTUCKY AND WILL SLOWLY MOVE SOUTH DURING THE DAY. BY FRIDAY MORNING THE FRONT WILL HAVE MOVED INTO CENTRAL TENNESSEE. THE 00GMT GFS IS WANTING TO SLOW THE FRONT DOWN AND SORT OF STALL IT OVER THE AREA ON FRIDAY...WHILE THE 12 GMT ECMWF WANTS TO MOVES IT SOUTH OF THE AREA MORE QUICKLY. IN GENERAL...I HAVE MORE CONFIDENCE IN THE ECMWF AND WILL BE NUDGING THE FORECAST TOWARD THE FASTER FRONTAL PASSAGE. IN EITHER CASE...AS THE FRONT MOVES TO THE SOUTH...DRIER AIR WILL BE MOVING INTO THE AREA AND MAKE THINGS MORE COMFORTABLE. EVEN THOUGH THE HIGHS WILL STILL BE A LITTLE ABOVE NORMAL. THE OVERNIGHT LOWS WILL DROP DUE TO THE DRIER AIR. IN THE MEAN TIME...KENTUCKY WILL BE UNDER A DIRTY RIDGE WITH WARM MOIST UNSTABLE AIR OVER THE AREA WHICH WILL BE ABLE TO PRODUCE MAINLY AFTERNOON AND EVENING CONVECTIVE THUNDERSTORMS AND SHOWERS AND WILL KEEP TEMPERATURES WARM AND MISERABLE. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 700 AM EDT SUN JUL 15 2012 SCT SHRA WITH A FEW TSTMS MOVING NE ACROSS CNTRL AND NERN KY THIS MORNING BUT ARE NOT AFFECTING THE TAF SITES JUST YET. MORE TSTMS ARE EXPECTED TO DEVELOP THROUGH THE MORNING AND CONTINUE THROUGH THE AFTERNOON...AND WILL ONCE AGAIN BRING TEMPORARY...LOCALIZED IFR OR WORSE TO ANY TERMINAL THAT SEES CONVECTION TODAY. HOWEVER...WITH LOW CONFIDENCE IN TIMING AND EXACT PLACEMENT...WILL CONTINUE WITH VC GROUPS. LOW LEVEL WINDS ARE EXPECTED TO REDEVELOP AFTER 12Z OUT OF THE SW TO AROUND 5 TO 10 KTS AND CONTINUE THROUGH THE EVENING BEFORE DIMINISHING WITH CONVECTION AFTER SUNSET. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...GEOGERIAN SHORT TERM...MB LONG TERM....JJ AVIATION...MB
AREA FORECAST DISCUSSION
NWS JACKSON KY
701 AM EDT SUN JUL 15 2012 .UPDATE... ISSUED AT 700 AM EDT SUN JUL 15 2012 SHOWERS HAVE INCREASED OVER ERN KY THIS MORNING WITH A FEW RUMBLES AS WELL...LENDING SOME CREDIBILITY TO THE HRRR AND NAM12...AND HAVE BENT THE GRIDS IN THIS DIRECTION THROUGH THE REMAINDER OF THE MORNING. ALSO UPDATED SKY...ALONG WITH TEMPS AND DEW PTS TO ESTABLISH TRENDS HEADING INTO THE DAY. OTHERWISE...THE FCST IS ESSENTIALLY ON TRACK. UPDATED ZONES WILL BE ISSUED SHORTLY. && .SHORT TERM...(TODAY THROUGH MONDAY) ISSUED AT 232 AM EDT SUN JUL 15 2012 ESSENTIALLY LOOKING AT A PERSISTENCE FORECAST FOR TODAY AND TONIGHT WITH LITTLE CHANGE ANTICIPATED IN THE OVERALL. THE QUESTION REMAINS WHERE AND WHEN CONVECTION WILL INITIATE...BUT THE NEAR TERM MODELS ARE STILL PLUGGING SOME EARLY MORNING DEVELOPMENT OVER CNTRL TN AND KY SPREADING EAST THROUGH THE MORNING AND CONTINUING THROUGH THE AFTERNOON BEFORE DIMINISHING THIS EVENING FOLLOWING THE LOSS OF DAYTIME HEATING. MODELS ARE IN GENERAL AGREEMENT IN DEVELOPING SOME HEALTHY INSTABILITY THIS MORNING...UPWARDS OF 3K J/KG MU CAPE AGAIN WITH CONVECTIVE TEMPS IN THE LOWER 80S AND CURRENT FCST HIGHS IN THE MID 80S. FCST PWATS CONTINUE TO RUN ABOUT 2 INCHES THROUGHOUT THE DAY...AND WITH A RIGHT ENTRANCE REGION OF A MODEST 50-60KT UPPER LEVEL JET TRAVERSING UP THE OHIO VALLEY THIS AFTERNOON...COUPLED WITH A MID LEVEL SHORT WAVE MOVING UP FROM THE TN VALLEY...CAN SEE LITTLE REASON THIS MORNING WHY WE WOULD NOT SEE SOME EFFICIENT TSTMS AGAIN LATER THIS MORNING CONTINUING THROUGH THE AFTERNOON...WITH LOCALLY HEAVY RAINFALL AGAIN THE PRIMARY CONCERN. MONDAY IS LOOKING A LITTLE MORE INTERESTING THIS MORNING WITH FCST SOUNDINGS DEPICTING A STRONGER CAP DEVELOPING BY LATE MORNING CONTINUING THROUGH THE PEAK HEATING HOURS AS THE STRONG BERMUDA HIGH IS PROGGED TO SHIFT WEST TOWARDS THE CENTRAL APPALACHIANS...WEAKENING SLIGHTLY IN THE PROCESS. DRIER...BUT WARMER MID LEVEL ADVECTION WILL EITHER SQUASH PRECIP CHANCES OR...IF THE CAP BREAKS...COULD RESULT IN SOME STRONG STORMS AGAIN DEVELOPING DURING THE AFTERNOON WITH DAMAGING WINDS POSSIBLE IN ADDITION TO THE THREAT FOR LOCALLY HEAVY RAINFALL. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 232 PM EDT SAT JUL 14 2012 THE MODELS ARE IN PRETTY GOOD AGREEMENT WITH THE GENERAL LONG WAVE PATTERN...HOWEVER THERE ARE SOME DIFFERENCES IN THE TIMING SOME OF THE SHORT WAVES LATER ON DURING THE PERIOD. ON MONDAY NIGHT...KENTUCKY WILL BE DOMINATED BY THE UPPER RIDGE WITH A MAJOR TROUGH JUST OFF THE WEST COAST. ALL THE FRONTAL ACTIVITY WILL BE WELL NORTH OF THE AREA AND THE COAL FIELDS WILL BE DOMINATED BY THE WARM...MOIST AND UNSTABLE AIR MASS. WITH TIME...AN UPPER TROUGH BEGINS TO DROP SOUTH FROM AN UPPER LOW CENTER OVER THE CANADIAN MARITIMES. THIS WILL ALLOW A COLD FRONT TO START MOVING TO THE SOUTH. BY THURSDAY MORNING...THE FRONT WILL BE OVER NORTHERN KENTUCKY AND WILL SLOWLY MOVE SOUTH DURING THE DAY. BY FRIDAY MORNING THE FRONT WILL HAVE MOVED INTO CENTRAL TENNESSEE. THE 00GMT GFS IS WANTING TO SLOW THE FRONT DOWN AND SORT OF STALL IT OVER THE AREA ON FRIDAY...WHILE THE 12 GMT ECMWF WANTS TO MOVES IT SOUTH OF THE AREA MORE QUICKLY. IN GENERAL...I HAVE MORE CONFIDENCE IN THE ECMWF AND WILL BE NUDGING THE FORECAST TOWARD THE FASTER FRONTAL PASSAGE. IN EITHER CASE...AS THE FRONT MOVES TO THE SOUTH...DRIER AIR WILL BE MOVING INTO THE AREA AND MAKE THINGS MORE COMFORTABLE. EVEN THOUGH THE HIGHS WILL STILL BE A LITTLE ABOVE NORMAL. THE OVERNIGHT LOWS WILL DROP DUE TO THE DRIER AIR. IN THE MEAN TIME...KENTUCKY WILL BE UNDER A DIRTY RIDGE WITH WARM MOIST UNSTABLE AIR OVER THE AREA WHICH WILL BE ABLE TO PRODUCE MAINLY AFTERNOON AND EVENING CONVECTIVE THUNDERSTORMS AND SHOWERS AND WILL KEEP TEMPERATURES WARM AND MISERABLE. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 700 AM EDT SUN JUL 15 2012 SCT SHRA WITH A FEW TSTMS MOVING NE ACROSS CNTRL AND NERN KY THIS MORNING BUT ARE NOT AFFECTING THE TAF SITES JUST YET. MORE TSTMS ARE EXPECTED TO DEVELOP THROUGH THE MORNING AND CONTINUE THROUGH THE AFTERNOON...AND WILL ONCE AGAIN BRING TEMPORARY...LOCALIZED IFR OR WORSE TO ANY TERMINAL THAT SEES CONVECTION TODAY. HOWEVER...WITH LOW CONFIDENCE IN TIMING AND EXACT PLACEMENT...WILL CONTINUE WITH VC GROUPS. LOW LEVEL WINDS ARE EXPECTED TO REDEVELOP AFTER 12Z OUT OF THE SW TO AROUND 5 TO 10 KTS AND CONTINUE THROUGH THE EVENING BEFORE DIMINISHING WITH CONVECTION AFTER SUNSET. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...MB SHORT TERM...MB LONG TERM....JJ AVIATION...MB
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
942 AM EDT SUN JUL 15 2012 .SYNOPSIS... THE COMBINATION OF A MID-LEVEL DISTURBANCE CROSSING THE GREAT LAKES AND A MOIST AIR MASS IN PLACE ACROSS THE UPPER OHIO VALLEY WILL MAKE SHOWERS AND THUNDERSTORMS LIKELY BY THIS AFTERNOON. A DRY START TO THE WEEK IS THEN EXPECTED AS HIGH PRESSURE ALOFT APPROACHES FROM THE SOUTHWEST. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... UPDATE TO REMOVE MENTION OF MORNING FOG. THE LATEST RAP MID-LEVEL ANALYSIS INDICATES THE UPPER OHIO VALLEY IN A SOUTHWESTERLY FLOW BETWEEN A RIDGE ACROSS THE CAROLINAS AND A TROUGH ACROSS THE WESTERN GREAT LAKES. AT THE SURFACE, DISCERNIBLE FRONTAL/PRESSURE FEATURES ARE LACKING WITH A BROAD AREA OF TDS IN THE UPPER 60S TO LOWER 70S ACROSS THE REGION. A SATURATED ATMOSPHERIC COLUMN REMAINS IN PLACE WITH PRECIPITABLE WATER VALUES IN THE 1.8-2.0 INCH RANGE EARLY THIS MORNING. DESPITE ONLY WEAK CAPE REMAINING, ABUNDANT MOISTURE IN PLACE IS ENOUGH TO SUPPORT WIDELY SCATTERED SHOWERS MOVING ACROSS THE AREA. THE SOUTHWESTERLY MID-LEVEL FLOW WILL BECOME MORE ZONAL TODAY AS THE TROUGH CROSSES THE GREAT LAKES. 500MB HEIGHTS WILL FALL SLIGHTLY AS THIS FEATURE PASSES NORTH OF THE AREA, PROVIDING ENOUGH FORCING IN A MOIST AND UNSTABLE ENVIRONMENT TO CONTRIBUTE TO THE DEVELOPMENT OF SHOWERS AND THUNDERSTORMS. COVERAGE OF CONVECTION IS EXPECTED TO INCREASE THIS MORNING AS ELEVATED INSTABILITY INCREASES FROM THE SOUTHWEST. EXPECT MOSTLY CLOUDY SKIES AGAIN TODAY WITH ABUNDANT MOISTURE. FOR TEMPS, HIGHS ARE CLOSEST TO MAV GUIDANCE, RANGING FROM THE UPPER 70S ALONG THE I-80 CORRIDOR AND EASTERN RIDGES TO THE MID 80S IN EASTERN OHIO. PWAT VALUES NEAR 2 INCHES WITH DEEP MOISTURE IN PLACE ALONG WITH MODERATE INSTABILITY WILL SUPPORT LOCALLY HEAVY DOWNPOURS TODAY. STORM MOTION OF AROUND 30KTS ALONG WITH THE GROUND BEING RELATIVELY DRY ACROSS MUCH OF THE AREA WILL BE LIMITING FACTORS FOR A FLASH FLOODING THREAT TODAY. HOWEVER, IF MULTIPLE STORMS TRAIN OVER AREAS, FLOODING COULD BECOME A THREAT. WITH 0-6KM BULK SHEAR AROUND 30KTS, ITS NOT OF THE QUESTION THAT A FEW ISOLATED STRONG TO SEVERE THUNDERSTORMS WILL DEVELOP THIS AFTERNOON INTO THE EVENING WITH THE PRIMARY THREAT BEING OF GUSTY WINDS AIDED BY MOISTURE LOADING. && .SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/... THERE IS OPERATIONAL MODEL AGREEMENT THAT THE MID-LEVEL TROUGH WILL SHIFT EAST OF THE AREA WITH THE FLOW BECOMING NORTHWESTERLY. WITH DEEP LAYER MOISTURE ADVECTING EAST OF THE AREA, CONVECTION WITH LOCALLY HEAVY DOWNPOURS WILL DIMINISH BY 06Z WITH POPS DECREASING TO SCHC QUICKLY AND DRY BY MONDAY MORNING. A DRY LAYER ABOVE 850MB ALONG WITH 500MB RIDGING BUILDING INTO THE OHIO VALLEY WILL ALLOW FOR A MOSTLY DRY FORECAST THROUGH THE DAY MONDAY AND INTO MONDAY NIGHT. MODERATE INSTABILITY MAY BE ENOUGH TO INITIATE AN ISOLATED SHOWER OR THUNDERSTORM SOUTHEAST OF PITTSBURGH INTO THE AFTERNOON. HIGHS MONDAY ARE A MAV/MET BLEND, RANGING FROM THE MID TO UPPER 80S ACROSS THE AREA. WITH TDS IN THE MID TO UPPER 60S TONIGHT AND MONDAY NIGHT, LOWS WILL RANGE FROM THE MID 60S ACROSS THE I-80 CORRIDOR TO NEAR 70 FOR THE PITTSBURGH METRO AND LOCATIONS SOUTHWESTWARD. ECMWF/GFS ARE IN AGREEMENT THAT THE 500MB RIDGE CENTERED ACROSS THE TENNESSEE VALLEY WILL EDGE TOWARD THE UPPER OHIO VALLEY ON TUESDAY. IN ADDITION, THE REGION WILL BE IN WARM AIR ADVECTION AHEAD OF A COLD FRONT APPROACHING FROM THE NORTHWEST. WITH 850MB TEMPS FORECAST TO WARM TO NEAR 20C BY TUESDAY AFTERNOON, THIS SUPPORTS HIGHS IN THE LOWER 90S ACROSS LOWLAND AREAS. WITH WARMEST TDS IN EASTERN OHIO, HEAT INDICES WILL APPROACH 100 AND A HEAT ADVISORY MAY BE NEEDED FOR LOCATIONS ALONG AND WEST OF I-77. TUESDAY WILL BE A WARM AND MUGGY NIGHT WITH TEMPS ONLY COOLING INTO THE LOWER 70S. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... GLOBAL MODEL AGREEMENT AND RUN-TO-RUN CONSISTENCY IS VERY GOOD ON THE SOUTHWARD PROGRESSION OF A COLD FRONT ACROSS THE AREA ON WEDNESDAY. THE GFS AND ECMWF BOTH DEPICT IT CLEARING VIRTUALLY ALL OF THE FORECAST AREA SAVE FOR MAYBE THE FARTHEST SOUTHEASTERN COUNTIES BY THURSDAY MORNING. BECAUSE OF THIS AND DUE TO A MUCH DRIER COLUMN FORECAST TO INFILTRATE THE AREA AFTER THIS TIME FRAME...THE FORECAST WAS DRIED OUT BEYOND WEDNESDAY NIGHT. THE RESULTANT DEEP NORTHWESTERLY FLOW WILL BRING MUCH LESS HUMID CONDITIONS INTO THE REGION...HOWEVER WITH 850 MB TEMPERATURES FROM THE MODEL CONSENSUS STILL RUNNING IN THE MID TEENS...TEMPERATURES ARE LIKELY TO REMAIN AT LEAST UP TOWARD NORMAL HIGHS FOR JULY. FRIES && .AVIATION /14Z SUNDAY THROUGH THURSDAY/... THUNDERSTORMS HAVE CLEARED ALL SITES TO THE NORTHEAST FOR THE EVENING AS OF 0530Z. SOME SHOWER ACTIVITY CONTINUES TO DEVELOP OVER EASTERN OHIO AND MOVE NORTHEASTWARD...BUT IT IS RATHER SCATTERED. THIS WILL NOT BE CARRIED AT ANY PARTICULAR TERMINAL...HOWEVER CONTINUED INPUT OF MOISTURE INTO THE LOWER LEVELS FROM ANY ADDITIONAL SHOWERS WILL ONLY INCREASE THE LIKELIHOOD OF VISIBILITIES STARTING TO SLIDE OFF WITHIN THE NEXT 1-3 HOURS. ALL SITES SHOULD GO MVFR PER BOTH STATISTICAL GUIDANCE AND PER SUGGESTIONS FROM BUFKIT DATA. SHOWERS WILL REDEVELOP BY LATE MORNING SUNDAY AGAIN AS THINGS BEGIN TO DESTABILIZE...WHICH SHOULD ALLOW FOR FOG TO BREAKUP BY THAT TIME. FRIES OUTLOOK...SUNDAY NIGHT THROUGH THURSDAY... WEAK RIDGING SHOULD PROVIDE GENERALLY VFR CONDITIONS MONDAY INTO TUESDAY. A COLD FRONT WILL SAG SOUTHWARD ACROSS THE GREAT LAKES AND THROUGH THE OHIO VALLEY TUESDAY NIGHT AND WEDNESDAY. RESTRICTIONS CAN BE EXPECTED IN SCATTERED PREFRONTAL THUNDERSTORMS. PREVAILING VFR WEATHER SHOULD RETURN BY THURSDAY AS A SURFACE HIGH BUILDS IN. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
636 AM EDT SUN JUL 15 2012 .SYNOPSIS... THE COMBINATION OF A MID-LEVEL DISTURBANCE CROSSING THE GREAT LAKES AND A MOIST AIR MASS IN PLACE ACROSS THE UPPER OHIO VALLEY WILL MAKE SHOWERS AND THUNDERSTORMS LIKELY BY THIS AFTERNOON. A DRY START TO THE WEEK IS THEN EXPECTED AS HIGH PRESSURE ALOFT APPROACHES FROM THE SOUTHWEST. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... THE LATEST RAP MID-LEVEL ANALYSIS INDICATES THE UPPER OHIO VALLEY IN A SOUTHWESTERLY FLOW BETWEEN A RIDGE ACROSS THE CAROLINAS AND A TROUGH ACROSS THE WESTERN GREAT LAKES. AT THE SURFACE, DISCERNIBLE FRONTAL/PRESSURE FEATURES ARE LACKING WITH A BROAD AREA OF TDS IN THE UPPER 60S TO LOWER 70S ACROSS THE REGION. A SATURATED ATMOSPHERIC COLUMN REMAINS IN PLACE WITH PRECIPITABLE WATER VALUES IN THE 1.8-2.0 INCH RANGE EARLY THIS MORNING. DESPITE ONLY WEAK CAPE REMAINING, ABUNDANT MOISTURE IN PLACE IS ENOUGH TO SUPPORT WIDELY SCATTERED SHOWERS MOVING ACROSS THE AREA. THE SOUTHWESTERLY MID-LEVEL FLOW WILL BECOME MORE ZONAL TODAY AS THE TROUGH CROSSES THE GREAT LAKES. 500MB HEIGHTS WILL FALL SLIGHTLY AS THIS FEATURE PASSES NORTH OF THE AREA, PROVIDING ENOUGH FORCING IN A MOIST AND UNSTABLE ENVIRONMENT TO CONTRIBUTE TO THE DEVELOPMENT OF SHOWERS AND THUNDERSTORMS. COVERAGE OF CONVECTION IS EXPECTED TO INCREASE THIS MORNING AS ELEVATED INSTABILITY INCREASES FROM THE SOUTHWEST. EXPECT MOSTLY CLOUDY SKIES AGAIN TODAY WITH ABUNDANT MOISTURE. FOR TEMPS, HIGHS ARE CLOSEST TO MAV GUIDANCE, RANGING FROM THE UPPER 70S ALONG THE I-80 CORRIDOR AND EASTERN RIDGES TO THE MID 80S IN EASTERN OHIO. PWAT VALUES NEAR 2 INCHES WITH DEEP MOISTURE IN PLACE ALONG WITH MODERATE INSTABILITY WILL SUPPORT LOCALLY HEAVY DOWNPOURS TODAY. STORM MOTION OF AROUND 30KTS ALONG WITH THE GROUND BEING RELATIVELY DRY ACROSS MUCH OF THE AREA WILL BE LIMITING FACTORS FOR A FLASH FLOODING THREAT TODAY. HOWEVER, IF MULTIPLE STORMS TRAIN OVER AREAS, FLOODING COULD BECOME A THREAT. WITH 0-6KM BULK SHEAR AROUND 30KTS, ITS NOT OF THE QUESTION THAT A FEW ISOLATED STRONG TO SEVERE THUNDERSTORMS WILL DEVELOP THIS AFTERNOON INTO THE EVENING WITH THE PRIMARY THREAT BEING OF GUSTY WINDS AIDED BY MOISTURE LOADING. && .SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/... THERE IS OPERATIONAL MODEL AGREEMENT THAT THE MID-LEVEL TROUGH WILL SHIFT EAST OF THE AREA WITH THE FLOW BECOMING NORTHWESTERLY. WITH DEEP LAYER MOISTURE ADVECTING EAST OF THE AREA, CONVECTION WITH LOCALLY HEAVY DOWNPOURS WILL DIMINISH BY 06Z WITH POPS DECREASING TO SCHC QUICKLY AND DRY BY MONDAY MORNING. A DRY LAYER ABOVE 850MB ALONG WITH 500MB RIDGING BUILDING INTO THE OHIO VALLEY WILL ALLOW FOR A MOSTLY DRY FORECAST THROUGH THE DAY MONDAY AND INTO MONDAY NIGHT. MODERATE INSTABILITY MAY BE ENOUGH TO INITIATE AN ISOLATED SHOWER OR THUNDERSTORM SOUTHEAST OF PITTSBURGH INTO THE AFTERNOON. HIGHS MONDAY ARE A MAV/MET BLEND, RANGING FROM THE MID TO UPPER 80S ACROSS THE AREA. WITH TDS IN THE MID TO UPPER 60S TONIGHT AND MONDAY NIGHT, LOWS WILL RANGE FROM THE MID 60S ACROSS THE I-80 CORRIDOR TO NEAR 70 FOR THE PITTSBURGH METRO AND LOCATIONS SOUTHWESTWARD. ECMWF/GFS ARE IN AGREEMENT THAT THE 500MB RIDGE CENTERED ACROSS THE TENNESSEE VALLEY WILL EDGE TOWARD THE UPPER OHIO VALLEY ON TUESDAY. IN ADDITION, THE REGION WILL BE IN WARM AIR ADVECTION AHEAD OF A COLD FRONT APPROACHING FROM THE NORTHWEST. WITH 850MB TEMPS FORECAST TO WARM TO NEAR 20C BY TUESDAY AFTERNOON, THIS SUPPORTS HIGHS IN THE LOWER 90S ACROSS LOWLAND AREAS. WITH WARMEST TDS IN EASTERN OHIO, HEAT INDICES WILL APPROACH 100 AND A HEAT ADVISORY MAY BE NEEDED FOR LOCATIONS ALONG AND WEST OF I-77. TUESDAY WILL BE A WARM AND MUGGY NIGHT WITH TEMPS ONLY COOLING INTO THE LOWER 70S. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... GLOBAL MODEL AGREEMENT AND RUN-TO-RUN CONSISTENCY IS VERY GOOD ON THE SOUTHWARD PROGRESSION OF A COLD FRONT ACROSS THE AREA ON WEDNESDAY. THE GFS AND ECMWF BOTH DEPICT IT CLEARING VIRTUALLY ALL OF THE FORECAST AREA SAVE FOR MAYBE THE FARTHEST SOUTHEASTERN COUNTIES BY THURSDAY MORNING. BECAUSE OF THIS AND DUE TO A MUCH DRIER COLUMN FORECAST TO INFILTRATE THE AREA AFTER THIS TIME FRAME...THE FORECAST WAS DRIED OUT BEYOND WEDNESDAY NIGHT. THE RESULTANT DEEP NORTHWESTERLY FLOW WILL BRING MUCH LESS HUMID CONDITIONS INTO THE REGION...HOWEVER WITH 850 MB TEMPERATURES FROM THE MODEL CONSENSUS STILL RUNNING IN THE MID TEENS...TEMPERATURES ARE LIKELY TO REMAIN AT LEAST UP TOWARD NORMAL HIGHS FOR JULY. FRIES && .AVIATION /12Z SUNDAY THROUGH THURSDAY/... THUNDERSTORMS HAVE CLEARED ALL SITES TO THE NORTHEAST FOR THE EVENING AS OF 0530Z. SOME SHOWER ACTIVITY CONTINUES TO DEVELOP OVER EASTERN OHIO AND MOVE NORTHEASTWARD...BUT IT IS RATHER SCATTERED. THIS WILL NOT BE CARRIED AT ANY PARTICULAR TERMINAL...HOWEVER CONTINUED INPUT OF MOISTURE INTO THE LOWER LEVELS FROM ANY ADDITIONAL SHOWERS WILL ONLY INCREASE THE LIKELIHOOD OF VISIBILITIES STARTING TO SLIDE OFF WITHIN THE NEXT 1-3 HOURS. ALL SITES SHOULD GO MVFR PER BOTH STATISTICAL GUIDANCE AND PER SUGGESTIONS FROM BUFKIT DATA. SHOWERS WILL REDEVELOP BY LATE MORNING SUNDAY AGAIN AS THINGS BEGIN TO DESTABILIZE...WHICH SHOULD ALLOW FOR FOG TO BREAKUP BY THAT TIME. FRIES OUTLOOK...SUNDAY NIGHT THROUGH THURSDAY... WEAK RIDGING SHOULD PROVIDE GENERALLY VFR CONDITIONS MONDAY INTO TUESDAY. A COLD FRONT WILL SAG SOUTHWARD ACROSS THE GREAT LAKES AND THROUGH THE OHIO VALLEY TUESDAY NIGHT AND WEDNESDAY. RESTRICTIONS CAN BE EXPECTED IN SCATTERED PREFRONTAL THUNDERSTORMS. PREVAILING VFR WEATHER SHOULD RETURN BY THURSDAY AS A SURFACE HIGH BUILDS IN. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1121 AM EDT SUN JUL 15 2012 .UPDATE... ISSUED AT 1119 AM EDT SUN JUL 15 2012 MORNING UPDATE MAINLY DEALS WITH TWEAKS TO THE FOG OVER LK SUPERIOR AND CLOUD COVER THIS AFTN OVER INTERIOR LOCATIONS. FOR THE FOG...EXTENDED THE DENSE FOG ADVY FOR NORTHERN AREAS THROUGH THIS AFTN DUE TO RECENT WEBCAMS ALONG THE NRN KEWEENAW SHORELINE SHOWING DENSE FOG AT THIS HOUR. FARTHER SOUTH AND EAST...WEBCAMS AND SHIP OBS THIS MORNING SHOWING THE EXPANSE OF CLOUDS OVER THE SE LK SUPERIOR MAINLY IN THE FORM OF LOW STRATUS. THUS...WILL LET THAT ADVY EXPIRE AT NOON. HIGH RES MODELS ARE ALL SHOWING DIURNAL CU AND LIGHT SHOWERS DEVELOPING OVER THE WRN/CNTRL CWA AWAY FROM THE LK BREEZES OFF LK SUPERIOR. AREAS FROM WRN LK SUPERIOR TO THE THUNDER BAY AND N SAW SOME SCATTERED ACCAS EARLY THIS MORNING...WHICH SEEMS TO BE JUST E OF THE VERY DRY AIR ON THE 12Z KINL SOUNDING. BUT WITH THE SLOW LLVL WINDS NOT PUSHING THE DRY AIR E VERY QUICKLY...THINKING THE LINGERING LLVL MOISTURE WILL BE ENOUGH TO DEVELOP A LARGER AREA OF CU THAN PREVIOUSLY THOUGHT. THEREFORE...BUMPED SKIES UP TO PARTLY CLOUDY FOR MUCH OF THE INTERIOR W AND CNTRL. SINCE WEAK SHORTWAVE ENERGY WILL TRY TO WORK INTO THE AREA THIS AFTN FROM MORNING SHOWERS IN NW MN...THAT MAY BE ENOUGH TO HELP PRODUCE AN ISOLATED SHOWER OR TWO. WITH ALL OF THE HIGH RES MODELS AND THE NEW 12Z NAM KICKING OFF SHOWERS...EVEN THOUGH THEY MAY BE OVERDOING THE LLVL TD VALUES SOME...WILL INTRODUCE THEM AROUND 18Z OVER ERN ONTONAGON/GOGEBIC COUNTIES AND THEN DRIFT SE BEFORE DIMINISHING IN THE LATE AFTN. SINCE THERE APPEARS TO BE PLENTY OF DRY AIR ABOVE H750...WILL KEEP THUNDER MENTION OUT AS THIS WILL LIKELY LIMIT CLOUD DEPTH TO A FEW KFT AND MAY EVEN HOLD OFF SHOWER DEVELOPMENT. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 520 AM EDT SUN JUL 15 2012 WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW TROF JUST E OF THE FCST AREA. SHRA/TSRA THAT ACCOMPANIED THE TROF ACROSS THE AREA YESTERDAY HAVE RECENTLY EXITED THE SE PORTION OF THE FCST AREA. IN ITS WAKE... CALM WIND/CLEARING SKIES AND MOISTURE FROM YESTERDAY`S RAINFALL HAS LED TO SOME FOG DEVELOPMENT. FOG WILL QUICKLY BURN OFF WITHIN A COUPLE HRS AFTER SUNRISE. UPSTREAM...A MID LEVEL RIDGE IS NOSING INTO THE DAKOTAS/WRN MN. AS THE RIDGE SHIFTS E TODAY...UPPER MI WILL FALL UNDER HEIGHT RISES/DEEP LAYER QVECTOR DIVERGENCE. MUCH DRIER AIR...MAINLY IN THE MID LEVELS PER UPSTREAM 00Z KINL/CWPL SOUNDINGS...WILL WORK AGAINST ANY AFTN CONVECTIVE DEVELOPMENT DESPITE LAKE BREEZES PROVIDING LOW-LEVEL FORCING. THE K-INDEX ON THE 00Z CWPL/KINL SOUNDINGS WAS -11/-14C RESPECTIVELY DUE TO VERY DRY AIR AROUND 700MB (DWPT DEPRESSIONS WERE IN EXCESS OF 40C). SO... GOING DRY FCST APPEARS ON TRACK DESPITE SOME HIGH RES GUIDANCE CONTINUING TO SHOW ISOLD CONVECTION OVER THE SCNTRL THIS AFTN. MIXING TO AROUND 800MB ON FCST SOUNDINGS SUPPORTS MAX TEMPS UPWARDS OF AROUND 90F. LIGHT GRADIENT WIND WILL ALLOW LAKE BREEZES OFF LAKE SUPERIOR AND LAKE MICHIGAN TO PROVIDE SOME COOLING LAKESIDE. SHORTWAVE ENERGY EJECTING FROM THE TROF CURRENTLY OVER THE WRN STATES WILL HEAD INTO SCNTRL CANADA TONIGHT. IN RESPONSE...LOW-LEVEL JET WILL INCREASE TO 45-50KT INTO THE NRN PLAINS. THIS WILL LIKELY SUPPORT A CLUSTER OF SHRA/TSRA ON THE NOSE OF THE LOW-LEVEL JET AND ALONG EDGE OF CAP ACROSS ND INTO SRN MANITOBA/NRN MN AND NRN ONTARIO. AT THIS TIME...IT STILL APPEARS LOW-LEVEL JET WILL BE W OF THE AREA AT 12Z MON...SO DO NOT ANTICIPATE ANY CONVECTION LATE TONIGHT...EXCEPT POSSIBLY OVER NW LAKE SUPERIOR/ISLE ROYALE. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 520 AM EDT SUN JUL 15 2012 BY 12Z MONDAY THE FRONTAL BOUNDARY WOULD BE ACROSS LAKE SUPERIOR /AS A WARM FRONT/...STRETCHING FROM THE SFC LOW SET UP FROM NW MN TO CENTRAL SD. DEPENDING ON THE AMOUNT OF MIXING /UP TO AROUND 800MB AT SAW/ A FEW GUSTS OF 30 TO 35KTS COULD BE POSSIBLE FROM LATE MORNING THROUGH THE REMAINDER OF THE DAYTIME HOURS. IF CLOUD COVER DOES NOT INHIBIT MIXING...THESE STRONGER GUSTS COULD BE POSSIBLE ACROSS THE DOWNSLOPE LOCATIONS NEAR LAKE SUPERIOR GIVEN THE STRENGTHENING SW FLOW. AS FOR THE OFFICIAL FCST...HAVE INCREASED WINDS QUITE A BIT FROM THE PREVIOUS FORECAST...WITH GUSTS OF 20-25KTS ACROSS MUCH OF THE CWA BY MID AFTERNOON. THE RECORD HIGH TEMP FOR MONDAY AT WFO MQT IS 95 DEGREES...WHICH MAY BE BROKEN BY THE END OF THE DAY. CURRENTLY GOING ONLY A COUPLE OF DEGREES COOLER THAN THIS RECORD...WITH 850MB TEMPS OF 22-24C ALLOWING SEVERAL SITES ACROSS THE INTERIOR W HALF OF UPPER MI REACHING 95 OR ABOVE. THE SFC LOW SHOULD PUSH ACROSS THE AREA MONDAY AFTERNOON THROUGH TUESDAY NIGHT. THE TRACK IS STILL UNCERTAIN...WITH THE 14/18Z GFS AND 15/00Z NAM PUSHING THE SFC LOW ACROSS THE KEWEENAW PENINSULA AND ACROSS LAKE SUPERIOR BY EARLY MONDAY EVENING. THE FARTHER SOUTH 14/12Z ECMWF INDICATES A BROADER LOW...STRETCHING ACROSS CENTRAL AND SOUTHERN UPPER MI MONDAY NIGHT. THE 14/12Z CANADIAN IS BEYOND CONSENSUS FROM MONDAY AFTERNOON ON...TRACKING THE SFC LOW ACROSS ONTARIO AND N LAKE SUPERIOR...AND WILL NOT BE USED IN THIS FORECAST UNTIL IT MOVES BACK IN LINE WITH THE REMAINDER OF AVAILABLE GUIDANCE WEDNESDAY MORNING. HIGH PRESSURE OVER CENTRAL CANADA TUESDAY MORNING WILL SLOWLY SHIFT SE ACROSS LAKE SUPERIOR AND UPPER MI TUESDAY THROUGH THURSDAY. THE COOLEST AFTERNOON TEMPS LOOK TO BE WEDNESDAY...TOPPING OUT IN THE 70S...COOLEST NEAR LAKE SUPERIOR AS DRY COOL AIR REMAINS. 850MB TEMPS WEDNESDAY WILL BE A COOL 10-12C. THE FCST FOR THE CWA WILL REMAIN DRY TUESDAY NIGHT THROUGH FRIDAY NIGHT. EXPECT THE SFC HIGH TO DRIFT E TO THE LOWER GREAT LAKES AND W QUEBEC BY DAYBREAK FRIDAY AND THE NEW ENGLAND COAST FRIDAY NIGHT...WITH A RIDGE REMAINING ACROSS THE UPPER GREAT LAKES REGION. A RELATIVELY WEAK SFC LOW STRETCHING FROM CENTRAL CANADA THROUGH THE CENTRAL PLAINS LOOKS TO BECOME BETTER ORGANIZED TO OUR W SATURDAY NIGHT...AS A SERIES OF DISTURBANCES NEAR FROM W AND CENTRAL CANADA AS 500MB RIDGE BECOMES SUPPRESSED ACROSS THE CENTRAL AND SOUTHERN PLAINS. KEPT CHANCE POPS FOR SATURDAY...ALTHOUGH CONFIDENCE IS MODERATE TO LOW FOR SPECIFICS THAT FAR OUT IN THIS FCST. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 749 AM EDT SUN JUL 15 2012 FOG WHICH HAS LED TO HIGHLY VARIABLE VIS/CIGS OVERNIGHT WILL BURN OFF OVER THE NEXT HR OR TWO...LEAVING VFR CONDITIONS TO PREVAIL TODAY AND TONIGHT AT KIWD/KCMX/KSAW. THERE IS A SMALL POTENTIAL FOR FOG TO REDEVELOP TONIGHT...BUT A SLOW INCREASE IN NEAR SFC WINDS WILL WORK TO LIMIT POTENTIAL. ALSO...SOIL MOISTURE WHICH PLAYED A ROLE IN FOG DEVELOPMENT OVERNIGHT WILL HAVE A CHANCE TO DRY OUT TODAY. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 520 AM EDT SUN JUL 15 2012 BIGGEST CONCERN IN THE SHORT TERM WILL BE FOG. 11-3.9MICRON SATELLITE IMAGERY INDICATES FOG (PROBABLY NOT STRATUS) EXPANDING S AND E FROM NCNTRL LAKE SUPERIOR. MORE FOG MAY BE DEVELOPING FROM KEWEENAW BAY TOWARD MARQUETTE/MUNISING. WITH DEVELOPING MESO HIGH PRES OVER THE LAKE TODAY...IT`S QUITE POSSIBLE FOG MAY END UP SPREADING TO THE SHORELINES AROUND THE ENTIRE LAKE TODAY. ALWAYS DIFFICULT TO FCST MARINE FOG...SO TRENDS WILL NEED TO MONITORED CLOSELY TODAY FOR MOVEMENT/DEVELOPMENT/DISSIPATION OF FOG. ONCE DAYLIGHT ARRIVES...VIS SATELLITE IMAGERY WILL PROVIDE A BETTER LOOK AT HOW THE FOG IS EVOLVING. QUITE POSSIBLE DENSE FOG ADVY MAY NEED TO BE ISSUED. FOR NOW...CARRIED FOG MENTION THRU EARLY AFTN OVER MAINLY CNTRL AND ERN LAKE SUPERIOR. OTHERWISE...WITH HIGH PRES DEVELOPING OVER LAKE SUPERIOR TODAY... WINDS WILL BE UNDER 15KT. ALTHOUGH WINDS WILL BECOME S-SE TONIGHT IN ADVANCE OF APPROACHING LOW PRES...SPEEDS SHOULD REMAIN 15KT OR LESS. THERE IS SOME UNCERTAINTY IN WHERE WARM FRONT ASSOCIATED WITH THE LOW WILL BE POSITIONED MON. AT THIS TIME...IT APPEARS THAT AT LEAST SRN PORTIONS OF THE LAKE WILL SEE INCREASING S-SW WINDS MON UPWARDS OF 20KT AS WARM FRONT DRIFTS N. AS LOW PASSES ACROSS THE AREA MON NIGHT...A COLD FRONT WILL PUSH S...BRINGING A SHIFT TO NORTHERLY WINDS UPWARDS OF 20KT INTO TUE MORNING. HIGH PRES WILL THEN BUILD INTO THE UPPER GREAT LAKES DURING THE MIDWEEK PERIOD...RESULTING IN WINDS UNDER 20KT. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... DENSE FOG ADVISORY UNTIL 6 PM EDT THIS EVENING FOR LSZ243>245- 263-264-266. DENSE FOG ADVISORY UNTIL NOON EDT TODAY FOR LSZ242-246>249-265. LAKE MICHIGAN... NONE. && $$ UPDATE...SRF SHORT TERM...ROLFSON LONG TERM...KF AVIATION...ROLFSON MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
750 AM EDT SUN JUL 15 2012 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 520 AM EDT SUN JUL 15 2012 WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW TROF JUST E OF THE FCST AREA. SHRA/TSRA THAT ACCOMPANIED THE TROF ACROSS THE AREA YESTERDAY HAVE RECENTLY EXITED THE SE PORTION OF THE FCST AREA. IN ITS WAKE... CALM WIND/CLEARING SKIES AND MOISTURE FROM YESTERDAY`S RAINFALL HAS LED TO SOME FOG DEVELOPMENT. FOG WILL QUICKLY BURN OFF WITHIN A COUPLE HRS AFTER SUNRISE. UPSTREAM...A MID LEVEL RIDGE IS NOSING INTO THE DAKOTAS/WRN MN. AS THE RIDGE SHIFTS E TODAY...UPPER MI WILL FALL UNDER HEIGHT RISES/DEEP LAYER QVECTOR DIVERGENCE. MUCH DRIER AIR...MAINLY IN THE MID LEVELS PER UPSTREAM 00Z KINL/CWPL SOUNDINGS...WILL WORK AGAINST ANY AFTN CONVECTIVE DEVELOPMENT DESPITE LAKE BREEZES PROVIDING LOW-LEVEL FORCING. THE K-INDEX ON THE 00Z CWPL/KINL SOUNDINGS WAS -11/-14C RESPECTIVELY DUE TO VERY DRY AIR AROUND 700MB (DWPT DEPRESSIONS WERE IN EXCESS OF 40C). SO... GOING DRY FCST APPEARS ON TRACK DESPITE SOME HIGH RES GUIDANCE CONTINUING TO SHOW ISOLD CONVECTION OVER THE SCNTRL THIS AFTN. MIXING TO AROUND 800MB ON FCST SOUNDINGS SUPPORTS MAX TEMPS UPWARDS OF AROUND 90F. LIGHT GRADIENT WIND WILL ALLOW LAKE BREEZES OFF LAKE SUPERIOR AND LAKE MICHIGAN TO PROVIDE SOME COOLING LAKESIDE. SHORTWAVE ENERGY EJECTING FROM THE TROF CURRENTLY OVER THE WRN STATES WILL HEAD INTO SCNTRL CANADA TONIGHT. IN RESPONSE...LOW-LEVEL JET WILL INCREASE TO 45-50KT INTO THE NRN PLAINS. THIS WILL LIKELY SUPPORT A CLUSTER OF SHRA/TSRA ON THE NOSE OF THE LOW-LEVEL JET AND ALONG EDGE OF CAP ACROSS ND INTO SRN MANITOBA/NRN MN AND NRN ONTARIO. AT THIS TIME...IT STILL APPEARS LOW-LEVEL JET WILL BE W OF THE AREA AT 12Z MON...SO DO NOT ANTICIPATE ANY CONVECTION LATE TONIGHT...EXCEPT POSSIBLY OVER NW LAKE SUPERIOR/ISLE ROYALE. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 520 AM EDT SUN JUL 15 2012 BY 12Z MONDAY THE FRONTAL BOUNDARY WOULD BE ACROSS LAKE SUPERIOR /AS A WARM FRONT/...STRETCHING FROM THE SFC LOW SET UP FROM NW MN TO CENTRAL SD. DEPENDING ON THE AMOUNT OF MIXING /UP TO AROUND 800MB AT SAW/ A FEW GUSTS OF 30 TO 35KTS COULD BE POSSIBLE FROM LATE MORNING THROUGH THE REMAINDER OF THE DAYTIME HOURS. IF CLOUD COVER DOES NOT INHIBIT MIXING...THESE STRONGER GUSTS COULD BE POSSIBLE ACROSS THE DOWNSLOPE LOCATIONS NEAR LAKE SUPERIOR GIVEN THE STRENGTHENING SW FLOW. AS FOR THE OFFICIAL FCST...HAVE INCREASED WINDS QUITE A BIT FROM THE PREVIOUS FORECAST...WITH GUSTS OF 20-25KTS ACROSS MUCH OF THE CWA BY MID AFTERNOON. THE RECORD HIGH TEMP FOR MONDAY AT WFO MQT IS 95 DEGREES...WHICH MAY BE BROKEN BY THE END OF THE DAY. CURRENTLY GOING ONLY A COUPLE OF DEGREES COOLER THAN THIS RECORD...WITH 850MB TEMPS OF 22-24C ALLOWING SEVERAL SITES ACROSS THE INTERIOR W HALF OF UPPER MI REACHING 95 OR ABOVE. THE SFC LOW SHOULD PUSH ACROSS THE AREA MONDAY AFTERNOON THROUGH TUESDAY NIGHT. THE TRACK IS STILL UNCERTAIN...WITH THE 14/18Z GFS AND 15/00Z NAM PUSHING THE SFC LOW ACROSS THE KEWEENAW PENINSULA AND ACROSS LAKE SUPERIOR BY EARLY MONDAY EVENING. THE FARTHER SOUTH 14/12Z ECMWF INDICATES A BROADER LOW...STRETCHING ACROSS CENTRAL AND SOUTHERN UPPER MI MONDAY NIGHT. THE 14/12Z CANADIAN IS BEYOND CONSENSUS FROM MONDAY AFTERNOON ON...TRACKING THE SFC LOW ACROSS ONTARIO AND N LAKE SUPERIOR...AND WILL NOT BE USED IN THIS FORECAST UNTIL IT MOVES BACK IN LINE WITH THE REMAINDER OF AVAILABLE GUIDANCE WEDNESDAY MORNING. HIGH PRESSURE OVER CENTRAL CANADA TUESDAY MORNING WILL SLOWLY SHIFT SE ACROSS LAKE SUPERIOR AND UPPER MI TUESDAY THROUGH THURSDAY. THE COOLEST AFTERNOON TEMPS LOOK TO BE WEDNESDAY...TOPPING OUT IN THE 70S...COOLEST NEAR LAKE SUPERIOR AS DRY COOL AIR REMAINS. 850MB TEMPS WEDNESDAY WILL BE A COOL 10-12C. THE FCST FOR THE CWA WILL REMAIN DRY TUESDAY NIGHT THROUGH FRIDAY NIGHT. EXPECT THE SFC HIGH TO DRIFT E TO THE LOWER GREAT LAKES AND W QUEBEC BY DAYBREAK FRIDAY AND THE NEW ENGLAND COAST FRIDAY NIGHT...WITH A RIDGE REMAINING ACROSS THE UPPER GREAT LAKES REGION. A RELATIVELY WEAK SFC LOW STRETCHING FROM CENTRAL CANADA THROUGH THE CENTRAL PLAINS LOOKS TO BECOME BETTER ORGANIZED TO OUR W SATURDAY NIGHT...AS A SERIES OF DISTURBANCES NEAR FROM W AND CENTRAL CANADA AS 500MB RIDGE BECOMES SUPPRESSED ACROSS THE CENTRAL AND SOUTHERN PLAINS. KEPT CHANCE POPS FOR SATURDAY...ALTHOUGH CONFIDENCE IS MODERATE TO LOW FOR SPECIFICS THAT FAR OUT IN THIS FCST. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 749 AM EDT SUN JUL 15 2012 FOG WHICH HAS LED TO HIGHLY VARIABLE VIS/CIGS OVERNIGHT WILL BURN OFF OVER THE NEXT HR OR TWO...LEAVING VFR CONDITIONS TO PREVAIL TODAY AND TONIGHT AT KIWD/KCMX/KSAW. THERE IS A SMALL POTENTIAL FOR FOG TO REDEVELOP TONIGHT...BUT A SLOW INCREASE IN NEAR SFC WINDS WILL WORK TO LIMIT POTENTIAL. ALSO...SOIL MOISTURE WHICH PLAYED A ROLE IN FOG DEVELOPMENT OVERNIGHT WILL HAVE A CHANCE TO DRY OUT TODAY. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 520 AM EDT SUN JUL 15 2012 BIGGEST CONCERN IN THE SHORT TERM WILL BE FOG. 11-3.9MICRON SATELLITE IMAGERY INDICATES FOG (PROBABLY NOT STRATUS) EXPANDING S AND E FROM NCNTRL LAKE SUPERIOR. MORE FOG MAY BE DEVELOPING FROM KEWEENAW BAY TOWARD MARQUETTE/MUNISING. WITH DEVELOPING MESO HIGH PRES OVER THE LAKE TODAY...IT`S QUITE POSSIBLE FOG MAY END UP SPREADING TO THE SHORELINES AROUND THE ENTIRE LAKE TODAY. ALWAYS DIFFICULT TO FCST MARINE FOG...SO TRENDS WILL NEED TO MONITORED CLOSELY TODAY FOR MOVEMENT/DEVELOPMENT/DISSIPATION OF FOG. ONCE DAYLIGHT ARRIVES...VIS SATELLITE IMAGERY WILL PROVIDE A BETTER LOOK AT HOW THE FOG IS EVOLVING. QUITE POSSIBLE DENSE FOG ADVY MAY NEED TO BE ISSUED. FOR NOW...CARRIED FOG MENTION THRU EARLY AFTN OVER MAINLY CNTRL AND ERN LAKE SUPERIOR. OTHERWISE...WITH HIGH PRES DEVELOPING OVER LAKE SUPERIOR TODAY... WINDS WILL BE UNDER 15KT. ALTHOUGH WINDS WILL BECOME S-SE TONIGHT IN ADVANCE OF APPROACHING LOW PRES...SPEEDS SHOULD REMAIN 15KT OR LESS. THERE IS SOME UNCERTAINTY IN WHERE WARM FRONT ASSOCIATED WITH THE LOW WILL BE POSITIONED MON. AT THIS TIME...IT APPEARS THAT AT LEAST SRN PORTIONS OF THE LAKE WILL SEE INCREASING S-SW WINDS MON UPWARDS OF 20KT AS WARM FRONT DRIFTS N. AS LOW PASSES ACROSS THE AREA MON NIGHT...A COLD FRONT WILL PUSH S...BRINGING A SHIFT TO NORTHERLY WINDS UPWARDS OF 20KT INTO TUE MORNING. HIGH PRES WILL THEN BUILD INTO THE UPPER GREAT LAKES DURING THE MIDWEEK PERIOD...RESULTING IN WINDS UNDER 20KT. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN...NONE. LAKE SUPERIOR... DENSE FOG ADVISORY UNTIL NOON EDT TODAY FOR LSZ242>249-263>266. LAKE MICHIGAN...NONE. && $$ SHORT TERM...ROLFSON LONG TERM...KF AVIATION...ROLFSON MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
656 AM CDT SUN JUL 15 2012 .UPDATED FOR 12Z AVIATION DISCUSSION... && .DISCUSSION... ANOTHER WARM DAY IS EXPECTED TODAY...WITH POTENTIALLY RECORD BREAKING HEAT ON MONDAY. ON TUESDAY A FRONTAL BOUNDARY WILL SLOWLY SLIDE SOUTHEAST THROUGH THE REGION. THIS WILL BE ACCOMPANIED BY A FEW SHOWERS AND THUNDERSTORMS...AS WELL AS SOME SLIGHTLY COOLER WEATHER. HOWEVER...THIS BOUNDARY WILL STRUGGLE TO MAKE IT SOUTH OF THE IA/MN BORDER...AND EVENTUALLY SWING BACK NORTHWARD AS A WARM FRONT...SETTING THE STAGE FOR ANOTHER HEAT WAVE FOR THE UPCOMING WEEKEND. TODAY THROUGH TUESDAY...SYNOPTIC ANALYSIS VIA NORTH AMERICAN WATER VAPOR IMAGERY AND 500MB HEIGHTS AND WINDS IDENTIFIED AN UPPER LEVEL TROUGH ACROSS THE GREAT LAKES...WITH A DOWNSTREAM RIDGE CENTERED OVER THE HIGH PLAINS. AN H850 THERMAL RIDGE WAS LONGITUDINALLY ORIENTED ON THE LEE SIDE OF THE ROCKIES...WHILE AT THE SURFACE A LOW PRESSURE SYSTEM WAS LOCATED IN EASTERN MONTANA. OVER THE NEXT COUPLE OF DAYS...A SHORTWAVE WILL ROUND THE UPPER LEVEL RIDGE AND CAUSE THE SURFACE LOW TO TRACK EASTWARD ACROSS THE US/CANADA BORDER. AS A RESULT...SOUTHWEST FLOW AND THE H850 THERMAL RIDGE WILL ALSO PROPAGATE EASTWARD AND BE LOCATED OVER THE UPPER MIDWEST BY MONDAY AFTERNOON. FROM A CONCEPTUAL MODEL PERSPECTIVE...THIS IS THE PERFECT SETUP FOR RECORD WARMTH. FROM A NUMERICAL MODEL PERSPECTIVE...THE NAM HAS BEEN THE WARMEST WITH WIDESPREAD HUNDREDS ACROSS THE CWA. IN FACT...FORECAST BURR SOUNDINGS FROM THE 15.00 NAM FOR MONDAY AFTERNOON ARE ALMOST IDENTICAL TO THE OBSERVED 00Z MSP SOUNDING FROM JULY 4 2012...WHICH YIELDED A HIGH TEMP OF 102 AT KMSP. THEREFORE...TEMPERATURES WERE INCREASED A COUPLE OF DEGREES FROM THE PREVIOUS FORECAST. AFTERNOON MIXING SHOULD KEEP DEWPOINTS IN THE UPPER 50S TO LOWER 60S...SO HEAT INDICES WILL NOT EXCEED THE ACTUAL AIR TEMPERATURE BY MORE THAN A FEW DEGREES. THEREFORE HAVE ISSUED A HEAT ADVISORY BEGINNING LATE MONDAY MORNING AND LASTING THROUGH LATE MONDAY EVENING. AS THE AFOREMENTIONED SURFACE LOW CONTINUES TOWARDS THE GREAT LAKES MONDAY NIGHT...A DIFFUSE COLD FRONT WILL GRADUALLY SLIDE SOUTHWARD THROUGH THE REGION. THE H850 THERMAL RIDGE WILL TAKE ON A MORE EAST/WEST ORIENTATION WITH THE WARMEST TEMPERATURES SOUTH OF THE CWA. ALSO...WINDS WILL WEAKEN SLIGHTLY SO NOT EXPECTING AS MUCH DYNAMICALLY INDUCED BOUNDARY LAYER HEATING DURING AFTERNOON HOURS. WITH THAT SAID...TEMPERATURES WILL STILL REACH THE MID 90S SOUTH OF THE FRONT ACROSS FAR SOUTHERN MINNESOTA...SO THE HEAT ADVISORY MAY NEED TO BE EXTENDED TO COVER THIS AREA. AS FAR AS PRECIP GOES...WARM AIR ALOFT SHOULD KEEP THE PRECIP CHANCES ACROSS THE NORTH FOR SUNDAY AND MONDAY. AS THE FRONTAL BOUNDARY SAGS SOUTHWARD...PRECIP CHANCES WILL INCREASE ALONG IT. LOW LEVEL CONVERGENCE IS RELATIVELY WEAK...AND THERE IS LITTLE IN THE WAY OF UPPER LEVEL FORCING. NONE THE LESS...A FEW ISOLATED SHOWERS AND THUNDERSTORMS WILL LIKELY PERCOLATE ALONG THIS BOUNDARY...WITH ISOLATED SEVERE WIND AND HAIL POSSIBLE. WEDNESDAY THROUGH SATURDAY...AS MENTIONED EARLIER...THIS BOUNDARY WILL STRUGGLE TO PUSH SOUTH OF THE IA/MN BORDER. BY MIDWEEK ANOTHER UPPER LEVEL WAVE WILL CROSS THE IDAHO PANHANDLE...RESULTING IN ANOTHER LEESIDE LOW IN SOUTHERN ALBERTA. THIS WILL DRAW THE LINGERING FRONTAL BOUNDARY BACK NORTHWARD AS A WARM FRONT. THE PRECIP WILL STILL REMAIN FOCUSED ALONG THIS BOUNDARY...WITH BETTER CHANCES NEAR THE MN/DAKOTA BORDER. THE UPPER LEVEL RIDGE WILL BUILD ACROSS THE CENTRAL CONUS...WITH HOT AND HUMID CONDITIONS RETURNING TO THE REGION BY THE END OF THE WEEK. GIVEN THE SYNOPTIC SETUP...INCREASED TEMPS A FEW DEGREES ABOVE GUIDANCE IN THE EXTENDED. SO IN SUMMATION...LOOKS LIKE THE DRY AND WARM CONDITIONS WILL STICK AROUND FOR AT LEAST THE NEXT 7 TO 10 DAYS. && .AVIATION.../12Z TAF ISSUANCE/ HIGH PRESSURE IS CENTERED OVER CENTRAL MINNESOTA EARLY THIS MORNING WITH CALM WINDS AND PATCHY FOG/HAZE AT SOME OF THE TAF SITES. A VERY BENIGN DAY AND EVENING IN STORE FOR AVIATION INTERESTS. NAM CU RULE INDICATES SCT050 THIS AFTERNOON IN WESTERN WISCONSIN BUT RAP CU RULE INDICATES NO CU. WENT WITH FEW050 KSTC EASTWARD. HIGH PRESSURE WILL EXIT THE AREA AND BY LATE MORNING WILL SEE SE WINDS AROUND THE 10 KT RANGE INCREASING IN THE AFTERNOON WITH...KAXN AND KRWF GUSTING UP TO 20 KNOTS IN THE AFTERNOON. OTHER SITES WILL SEE A LIGHT WEST WIND BACK TO THE SOUTH AND SOUTHEAST IN THE AFTERNOON WITH SPEEDS LESS THAN 10 KNOTS. FOR TONIGHT SOUTHEAST WINDS WILL REMAIN AROUND 10KTS. FOR MONDAY SKC WITH SOUTHWEST WINDS NEAR 20 KTS. KMSP...VFR THROUGH THE PERIOD. LIGHT WINDS BECOMING SOUTH SOUTHEAST 8-10 KNOTS SUNDAY AFTERNOON WITH A FEW GUSTS TO 13KTS. OUTLOOK... MONDAY...VFR. HOT. WINDS S-SW 15-20 KTS. TUESDAY...VFR. CHANCE OF TSRA WITH FRONTAL PASSAGE. WINDS BECOMING NE 5-10 KTS. WEDNESDAY...VFR. EAST WINDS 5 TO 10 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...HEAT ADVISORY FROM 11 AM TO 9 PM CDT MONDAY FOR ANOKA-BENTON- BLUE EARTH-BROWN-CARVER-CHIPPEWA-CHISAGO-DAKOTA-DOUGLAS- FARIBAULT-FREEBORN-GOODHUE-HENNEPIN-ISANTI-KANABEC- KANDIYOHI-LAC QUI PARLE-LE SUEUR-MARTIN-MCLEOD-MEEKER-MILLE LACS-MORRISON-NICOLLET-POPE-RAMSEY-REDWOOD-RENVILLE-RICE- SCOTT-SHERBURNE-SIBLEY-STEARNS-STEELE-STEVENS-SWIFT-TODD- WASECA-WASHINGTON-WATONWAN-WRIGHT-YELLOW MEDICINE. WI...HEAT ADVISORY FROM 11 AM TO 9 PM CDT MONDAY FOR BARRON-CHIPPEWA- DUNN-EAU CLAIRE-PEPIN-PIERCE-POLK-RUSK-ST. CROIX. && $$ JRB/DRL
AREA FORECAST DISCUSSION
NWS BUFFALO NY
1107 AM EDT SUN JUL 15 2012 .SYNOPSIS... A SOUTHWESTERLY FLOW WILL BRING INCREASINGLY HUMID AIR INTO THE REGION TODAY ALONG WITH SOME SHOWERS AND THUNDERSTORMS. A FEW STORMS WILL CONTAIN LOCALLY HEAVY RAINFALL...BUT ANY HEAVIER RAIN AMOUNTS WILL BE SPOTTY. A RIDGE OF HIGH PRESSURE WILL BUILD INTO THE LOWER GREAT LAKES MONDAY WITH MAINLY DRY CONDITIONS. && .NEAR TERM /THROUGH TONIGHT/... TODAY THERE WILL BE SOME SPOTTY HEAVY RAIN AS CONVECTION MOVES SLOWLY ACROSS THE AREA...HOWEVER COVERAGE OF THE BETTER RAINS WILL BE TOO SPARSE TO OFFER MUCH RELIEF TO THE ONGOING DROUGHT. AS IS OFTEN THE CASE...MODEL GUIDANCE IS STRUGGLING A BIT WITH CONVECTION...WITH A FAIR SPREAD OF QPF SOLUTIONS BETWEEN THE NAM/RGEM/GFS/EUROPEAN/SREF. THE HRRR HAS ALSO BEEN INCONSISTENT RUN TO RUN ON SPECIFICS. TWO MAIN AREAS OF RAIN ARE MOVING THROUGH THE AREA THIS MORNING. THE FIRST IS NOW MOVING INTO CENTRAL NY AND OUT OF OUR CWA...WITH A SECOND AREA OF SHOWERS MOVING INTO WESTERN NY. BOTH OF THESE AREAS ARE WEAKENING IN INTENSITY AND AREAL COVERAGE...EXCEPT FOR THE PORTION MOVING THROUGH CHAUTAUQUA COUNTY. EXPECT THIS TREND TO CONTINUE THROUGH EARLY AFTERNOON...WITH HEAVY RAIN CONFINED TO THE WESTERN SOUTHERN TIER...AND MUCH LIGHTER SHOWERS FOR THE REST OF THE AREA. THE NORTH COUNTRY WILL REMAIN DRY THROUGH EARLY AFTERNOON BEFORE A FEW SHOWERS POP UP LATER ON. AS HAS BEEN THE CASE THE PAST TWO DAYS...THE FLOW ALOFT WILL BE FAIRLY LIGHT. HOWEVER...TODAY THE PRECIPITABLE WATER VALUES WILL BE SIGNIFICANTLY GREATER...BETWEEN 1.75 INCHES AND 2.00 INCHES. WITH ANOMALOUSLY HIGH MOISTURE AVAILABLE IN THE COLUMN AND RELATIVELY SLOW STORM MOTION...ANY OF THE STRONGER STORMS WILL LAY DOWN SOME HEAVY RAIN IN ISOLATED AREAS WITH LOCAL AMOUNTS OF SEVERAL INCHES. DESPITE THE LOCALLY HEAVY RAIN...MOST LOCATIONS WILL SEE LESS THAN A QUARTER INCH WHICH WILL DO LITTLE OR NOTHING TO ALLEVIATE THE PARCHED SOIL CONDITIONS. THE UPPER TROF WILL SLOWLY MOVE ACROSS THE REGION BY THIS EVENING...BUT BY THIS TIME...DRIER AIR SHOULD BE IN PLACE IN THE BOUNDARY LAYER...SO SHOWER AND THUNDERSTORMS SHOULD TAPER OFF AND/OR EXIT EAST. THE WEAK FRONTAL BOUNDARY ASSOCIATED WITH THE TROF WILL NOT ACTUALLY CROSS THE REGION TONIGHT. THIS WILL KEEP MOIST AIR IN PLACE...AND DEPENDING ON RAINFALL TODAY COULD RESULT IN AREAS OF FOG TONIGHT. TEMPERATURES WILL BE A BIT COOLER TODAY THAN THEY WERE YESTERDAY...HOWEVER INCREASED MOISTURE WILL MAKE IT FEEL MORE MUGGY. HIGHS SHOULD BE IN THE LOWER 80S NORTH OF THE THRU-WAY...BUT MAY STAY IN THE UPPER 70S IN THE SOUTHERN TIER WHERE CLOUDS AND SHOWERS SHOULD LIMIT TEMPERATURES A BIT. FOR TONIGHT...LOWS WILL RANGE FROM THE LOWER 60S IN THE SOUTHERN TIER...TO AROUND 70 IN THE BUFFALO/ROCHESTER METRO AREAS. && .SHORT TERM /MONDAY THROUGH WEDNESDAY/... DURING THE COURSE OF MONDAY...THE AXIS OF A WEAK UPPER LEVEL TROUGH DRAPED FROM THE NEW ENGLAND COAST TO THE MID ATLANTIC STATES WILL SLIDE OUT TO SEA...ALLOWING THE LEADING EDGE OF BROAD/FLAT UPPER RIDGING TO EDGE NORTHEAST INTO THE LOWER LAKES. MEANWHILE AT THE SURFACE...LINGERING WEAK TROUGHINESS ACROSS THE LOWER LAKES AT THE START OF THE DAY WILL ALSO SLIDE EASTWARD...GIVING WAY TO MODEST LOW LEVEL RIDGING DURING THE AFTERNOON. GIVEN THESE DEVELOPMENTS...EXPECT THAT MONDAY SHOULD LARGELY BE ANOTHER DRY AND HOT/HUMID DAY...WITH 850 MB TEMPS OF +16C/+17C AGAIN SUPPORTING WIDESPREAD HIGHS IN THE UPPER 80S/LOWER 90S GIVEN WHAT SHOULD BE A DECENT AMOUNT OF SUNSHINE. WHILE BOTH THE GFS AND ECMWF BOTH SPIT OUT SOME LIGHT QPF ACROSS THE AREA PRIOR TO THE DEPARTURE OF THE LOW LEVEL TROUGH...BELIEVE THAT THIS IS OVERDONE GIVEN ONLY WEAK LINGERING FORCING AND FAIRLY WARM MID LEVEL TEMPS...WHICH SHOULD HELP TO KEEP ANY PRECIP ISOLATED IN COVERAGE AT BEST. HAVE THEREFORE KEPT POPS AT THE VERY LOW END OF THE SLIGHT CHANCE RANGE OR BELOW ON MONDAY. MONDAY NIGHT...BROAD/FLAT UPPER RIDGING WILL REMAIN INTACT ACROSS MUCH OF THE AREA...WHILE A SLOW MOVING COLD FRONTAL BOUNDARY OVER CENTRAL ONTARIO PROVINCE SAGS SOUTHWARD INTO THE UPPER LAKES AND SOUTHERN ONTARIO. WHILE I CANNOT TOTALLY RULE OUT SOME ASSOCIATED ISOLATED CONVECTION SNEAKING INTO THE SAINT LAWRENCE VALLEY TOWARD DAYBREAK ON TUESDAY...IT DOES APPEAR THAT THE FRONT WILL REMAIN FAR ENOUGH TO OUR NORTH AND THAT WE WILL REMAIN CAPPED ENOUGH FOR MAINLY DRY WEATHER TO CONTINUE AREAWIDE. WITH NO AIRMASS CHANGE AND AN INCREASING SOUTHWESTERLY LOW LEVEL FLOW EXPECTED WITH TIME IN RESPONSE TO THE APPROACHING FRONT...EXPECT DOWNRIGHT SULTRY TEMPERATURES WITH OVERNIGHT LOWS RANGING FROM THE MID AND UPPER 60S ACROSS INTERIOR SECTIONS...TO THE LOWER 70S ACROSS THE LAKE PLAINS. ON TUESDAY...THE AFOREMENTIONED FRONT WILL CONTINUE TO SLOWLY SAG SOUTH TOWARD OUR REGION...WITH NOTABLE TIMING DIFFERENCES SEEN AMONGST THE VARIOUS GUIDANCE PACKAGES. THE 00Z NAM IS AN EXTREMELY FAST OUTLIER THAT BRINGS THE FRONT COMPLETELY THROUGH THE AREA BY THE END OF THE DAY...WHICH SEEMS HIGHLY UNLIKELY GIVEN ITS NEAR-PARALLEL ORIENTATION TO THE UPPER LEVEL FLOW...NOT TO MENTION THE PROPENSITY FOR SUCH BOUNDARIES TO GET HUNG UP ACROSS THE LOWER LAKES AT THIS TIME OF YEAR. FOR THIS REASON...HAVE COMPLETELY DISREGARDED THIS SOLUTION. OF THE REMAINING GUIDANCE...THE GFS REMAINS A BIT ON THE FASTER SIDE THOUGH NOT AS FAST AS ITS PREVIOUS RUNS...BRINGING THE BOUNDARY INTO NORTHERN NEW YORK/LAKE ONTARIO BY THE END OF THE DAY...WHICH IS CLOSE ENOUGH TO GENERATE SOME CONVECTION ACROSS BOTH THE NORTH COUNTRY AND NIAGARA/ORLEANS COUNTIES. MEANWHILE...THE VERY CONSISTENT ECMWF REMAINS A TOUCH SLOWER THAN THE GFS AND ONLY BRINGS A RISK OF CONVECTION INTO THE NORTH COUNTRY...WITH THE 00Z GEM GLOBAL A BIT SLOWER STILL. AT THIS JUNCTURE...FEEL A COMPROMISE BETWEEN THE GFS/ECMWF REPRESENTS THE MOST PLAUSIBLE SCENARIO...WHICH WOULD BRING AT LEAST A LOW TO MODEST CHANCE OF CONVECTION TO LAKE ONTARIO AND THE NORTH COUNTRY BY LATE IN THE DAY. FURTHER TO THE SOUTH...CONDITIONS SHOULD REMAIN DRY THROUGH THE DAY ON TUESDAY...THANKS TO BOTH GREATER DISTANCE FROM THE FRONT AND STRONG MID LEVEL CAPPING...AS EVEN HOTTER AIR RIDES EAST ALONG THE PERIPHERY OF THE MAIN UPPER LEVEL RIDGE. A CONSENSUS OF THE GFS/GEM/ECMWF SUPPORTS 850 MB TEMPS RISING TO THE +20/+21C RANGE AREAWIDE DURING THE COURSE OF TUESDAY...AND THIS COUPLED WITH GOOD MIXING AND A DECENT AMOUNT OF SUN WILL LIKELY RESULT IN A REAL SCORCHER OF A DAY SOUTH OF LAKE ONTARIO. AT THIS POINT...WIDESPREAD HIGHS IN THE LOWER TO MID 90S APPEAR TO BE A SOLID BET...WITH UPPER 90S NOT AT ALL OUT OF THE QUESTION FOR THE NORMAL HOT SPOTS IN INTERIOR PORTIONS OF OUR CWA. COUPLED WITH DEWPOINTS IN THE MID TO UPPER 60S...SOME LOCATIONS SOUTH OF LAKE ONTARIO COULD SEE APPARENT TEMPERATURES REACHING THE 100 DEGREE MARK TUESDAY AFTERNOON...WHICH WOULD NECESSITATE THE ISSUANCE OF A HEAT ADVISORY. AS IT REMAINS FAR TOO EARLY FOR THAT...FOR NOW WILL JUST MENTION THIS POTENTIAL IN THE HWO. EAST OF LAKE ONTARIO...SOMEWHAT GREATER AMOUNTS OF CLOUD COVER WILL LIKELY HELP KEEP TEMPS A LITTLE COOLER...THOUGH IT SHOULD STILL BE UNCOMFORTABLY HOT EVEN THERE WITH HIGHS IN THE UPPER 80S TO LOWER 90S. TUESDAY NIGHT AND WEDNESDAY...THE COLD FRONT WILL SLOWLY SAG SOUTH ACROSS THE REGION...BRINGING A RISK OF CONVECTION TO THE ENTIRE CWA...ALONG WITH THE POTENTIAL FOR LOCALLY HEAVY RAINFALL GIVEN PRECIPITABLE WATER VALUES IN THE VICINITY OF AROUND 2 INCHES. AT THIS JUNCTURE...THE TIMING OF THIS BOUNDARY REMAINS AN ISSUE WITH THE GFS REMAINING THE FASTEST...THE CANADIAN THE SLOWEST...AND THE ECMWF IN THE MIDDLE...WITH FROPA TIMES RANGING BETWEEN EARLY TO MID WEDNESDAY MORNING AND WEDNESDAY AFTERNOON. GIVEN THAT THIS FRONT APPEARS TO BE ANAFRONTAL WITH MOST OF ITS PRECIP FALLING BEHIND THE ACTUAL SURFACE BOUNDARY...THIS MEANS THAT ANY ASSOCIATED CONVECTION COULD END AS EARLY AS SOMETIME WEDNESDAY MORNING...OR AS LATE AS THE END OF THE DAY WEDNESDAY. GIVEN THE CONTINUED UNCERTAINTIES IN TIMING AND THE AFOREMENTIONED NEAR-PARALLEL ORIENTATION OF THE FRONT TO THE UPPER FLOW...FEEL IT IS BEST TO SLOW DOWN THE TIMING OF THIS FRONT AND ITS ASSOCIATED CONVECTION A BIT FROM THE PREVIOUS FORECAST...FAVORING A COMPROMISE SOLUTION ALONG THE LINES OF THE ECMWF. AS A RESULT...CHANCES FOR CONVECTION WILL BE IN PLACE FROM TUESDAY NIGHT THROUGH WEDNESDAY MORNING ACROSS THE ENTIRE AREA...BEFORE DIMINISHING FROM NORTH TO SOUTH DURING THE COURSE OF WEDNESDAY AFTERNOON. TEMPERATURE-WISE... EXPECT ANOTHER SULTRY NIGHT IN ADVANCE OF THE FRONT TUESDAY NIGHT WITH LOWS AGAIN RANGING FROM THE UPPER 60S TO LOWER 70S...FOLLOWED BY SOMEWHAT COOLER HIGHS IN THE UPPER 70S TO MID 80S ON WEDNESDAY GIVEN THE PASSAGE OF THE FRONT AND ITS ASSOCIATED CLOUD COVER/PRECIP. && .LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/... SIMPLY PUT...SPRAWLING CANADIAN HIGH PRESSURE WILL BUILD SOUTHEAST ACROSS THE GREAT LAKES AND NORTHEAST DURING THIS PERIOD...BRINGING A RETURN TO DRY WEATHER ALONG WITH A COOLER AND NOTICEABLY LESS HUMID AIRMASS. IN TERMS OF ACTUAL TEMPERATURES...EXPECT DAILY HIGHS TO FALL BACK INTO THE MID 70S TO LOWER 80S FOR BOTH THURSDAY AND FRIDAY...BEFORE WARMING BACK INTO THE LOWER TO MID 80S ON SATURDAY AS WARMING COMMENCES ALOFT. MEANWHILE...NIGHTTIME LOWS WILL RANGE IN THE MID 50S TO LOWER 60S ALL THREE NIGHTS. HUMIDITY LEVELS WILL ALSO BE MUCH MORE COMFORTABLE...WITH DEWPOINTS REMAINING IN THE MID TO UPPER 50S DURING THE BULK OF THE PERIOD. && .AVIATION /15Z SUNDAY THROUGH THURSDAY/... AN AREA OF SHOWERS WILL CONTINUE TO MOVE EAST ACROSS THE REGION THROUGH EARLY AFTERNOON. THUNDERSTORM COVERAGE IS VERY SPARSE RIGHT NOW WITH JUST SOME STRIKES NEAR THE PA SATE LINE WHICH WILL IMPACT KJHW FOR THE NEXT HOUR OR TWO. THIS AFTERNOON WITH SOME LIMITED DAYTIME HEATING EXPECT SCATTERED STORMS TO DEVELOP ONCE AGAIN...MAINLY ACROSS THE SOUTHERN TIER INTO THE FINGER LAKES AND CENTRAL NY. EXPECT MAINLY VFR AND MVFR CONDITIONS MOST OF THE TIME IN THE LIGHT RAIN...BUT ANY EMBEDDED THUNDERSTORMS WILL PRODUCE LOCALIZED IFR. AFTERWARD...EXPECT A GENERAL CLEARING TREND FROM WEST TO EAST LATE THIS AFTERNOON AND EVENING. THIS SHOULD RESULT IN MAINLY VFR CONDITIONS...BUT THERE WILL BE AN INCREASING CHANCE FOR FOG OVERNIGHT. THE COMBINATION OF LIGHT WINDS AND LINGERING BOUNDARY LAYER MOISTURE MAY RESULT IN FAIRLY WIDESPREAD FOG. WINDS MAY LIMIT HOW LOW VSBY DROPS AT BUF/IAG/ROC/ART...BUT DENSE FOG MAY DEVELOP AT JHW...IN A RELATIVELY LIGHT FLOW. OUTLOOK... MONDAY AND TUESDAY...MAINLY VFR. TUESDAY NIGHT...AREAS OF MVFR IN SCATTERED -SHRA/-TSRA. WEDNESDAY...BECOMING VFR. THURSDAY...VFR. && .MARINE... HIGH PRESSURE WILL REMAIN ANCHORED ALONG THE MID ATLANTIC COAST THROUGH EARLY NEXT WEEK. MEANWHILE A WEAK TROUGH WILL APPROACH THE LOWER LAKES TODAY AND ALLOW SOUTHWEST WINDS TO INCREASE SOMEWHAT TO THE 10-15 KNOT RANGE...WITH THE STRONGEST WINDS ON LAKE ERIE. EXPECT CONDITIONS TO REMAIN BELOW SMALL CRAFT CRITERIA...BUT WAVES MAY GET A LITTLE CHOPPY ON LAKE ERIE. A RIDGE OF HIGH PRESSURE WILL NOSE INTO THE LOWER LAKES MONDAY WITH RELATIVELY LIGHT WINDS. SOUTHWEST WINDS WILL PICK UP AGAIN TUESDAY AHEAD OF A STRONGER COLD FRONT...ESPECIALLY ON LAKE ERIE WHERE CONDITIONS MAY APPROACH SMALL CRAFT ADVISORY CRITERIA. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...NONE. MARINE...NONE. && $$ SYNOPSIS...APFFEL NEAR TERM...APFFEL/HITCHCOCK SHORT TERM...JJR LONG TERM...JJR AVIATION...APFFEL/HITCHCOCK MARINE...APFFEL/JJR
AREA FORECAST DISCUSSION
NWS BUFFALO NY
757 AM EDT SUN JUL 15 2012 .SYNOPSIS... A SOUTHWESTERLY FLOW WILL BRING INCREASINGLY HUMID AIR INTO THE REGION TODAY ALONG WITH SOME SHOWERS AND THUNDERSTORMS. A FEW STORMS WILL CONTAIN LOCALLY HEAVY RAINFALL...BUT ANY HEAVIER RAIN AMOUNTS WILL BE SPOTTY. A RIDGE OF HIGH PRESSURE WILL BUILD INTO THE LOWER GREAT LAKES MONDAY WITH MAINLY DRY CONDITIONS. && .NEAR TERM /THROUGH TONIGHT/... TODAY WILL BRING AN OPPORTUNITY FOR DROUGHT RELIEF...HOWEVER SHOWERS AND THUNDERSTORMS WILL BE PATCHY IN NATURE...SO MANY COULD MISS OUT. AS IS OFTEN THE CASE...MODEL GUIDANCE IS STRUGGLING A BIT WITH CONVECTION...WITH A FAIR SPREAD OF QPF SOLUTIONS BETWEEN THE NAM/RGEM/GFS/EUROPEAN/SREF. THE HRRR HAS ALSO BEEN INCONSISTENT RUN TO RUN ON SPECIFICS. DESPITE THE DIFFERENCES...THERE SEEMS TO BE A FAIR CONSENSUS THAT THE MOST SIGNIFICANT RAINS WILL COME LATE MORNING AND EARLY AFTERNOON. EARLY MORNING RADAR TRENDS ARE BEGINNING TO SUPPORT THIS...AS SHOWERS AND THUNDERSTORMS EXPAND ACROSS LAKE ERIE AND SOUTHERN ONTARIO. IT APPEARS THE TRIGGER TO THIS IS A COMBINATION OF MOIST AIR IN THE BOUNDARY LAYER...AND THE CYCLONIC FLOW OUT AHEAD OF AN APPROACHING UPPER TROF. FOLLOWING MODEL GUIDANCE AND RADAR TRENDS...IT APPEARS STEADIEST RAINS WILL BE SOUTH OF LAKE ONTARIO...ESPECIALLY IN THE SOUTHERN TIER AND FINGER LAKES REGIONS. AS HAS BEEN THE CASE THE PAST TWO DAYS...THE FLOW ALOFT WILL BE FAIRLY LIGHT. HOWEVER...TODAY THE PRECIPITABLE WATER VALUES WILL BE SIGNIFICANTLY GREATER...BETWEEN 1.75 INCHES AND 2.00 INCHES. IF IT WERE NOT FOR THE VERY DRY CONDITIONS IN PLACE...THIS WOULD POSE A GREATER FLOODING THREAT...BUT EVEN STILL THERE IS A REAL POTENTIAL FOR FLOODING ALBEIT LOCALIZED. HAVE THE MOST CONCERN FOR THE SOUTHERN TIER...WHERE TERRAIN CAN FUNNEL RUNOFF. DUE TO THE HIT OR MISS NATURE OF CONVECTION...MEAN QPFS COULD BE A BIT MISLEADING. WHILE BASIN-WIDE QPF FORECASTS RANGE FROM NEAR A HALF INCH EXPECTED IN THE SOUTHERN TIER DOWN TO A TENTH OF AN INCH NORTH AND WEST OF I-90...RAINFALL BY LOCATION SHOULD VARY SIGNIFICANTLY. THE UPPER TROF WILL SLOWLY MOVE ACROSS THE REGION BY THIS EVENING...BUT BY THIS TIME...DRIER AIR SHOULD BE IN PLACE IN THE BOUNDARY LAYER...SO SHOWER AND THUNDERSTORMS SHOULD TAPER OFF AND/OR EXIT EAST. THE WEAK FRONTAL BOUNDARY ASSOCIATED WITH THE TROF WILL NOT ACTUALLY CROSS THE REGION TONIGHT. THIS WILL KEEP MOIST AIR IN PLACE...AND DEPENDING ON RAINFALL TODAY COULD RESULT IN AREAS OF FOG TONIGHT. TEMPERATURES WILL BE A BIT COOLER TODAY THAN THEY WERE YESTERDAY...HOWEVER INCREASED MOISTURE WILL MAKE IT FEEL MORE MUGGY. HIGHS SHOULD BE IN THE LOWER 80S NORTH OF THE THRU-WAY...BUT MAY STAY IN THE UPPER 70S IN THE SOUTHERN TIER WHERE CLOUDS AND SHOWERS SHOULD LIMIT TEMPERATURES A BIT. FOR TONIGHT...LOWS WILL RANGE FROM THE LOWER 60S IN THE SOUTHERN TIER...TO AROUND 70 IN THE BUFFALO/ROCHESTER METRO AREAS. && .SHORT TERM /MONDAY THROUGH WEDNESDAY/... DURING THE COURSE OF MONDAY...THE AXIS OF A WEAK UPPER LEVEL TROUGH DRAPED FROM THE NEW ENGLAND COAST TO THE MID ATLANTIC STATES WILL SLIDE OUT TO SEA...ALLOWING THE LEADING EDGE OF BROAD/FLAT UPPER RIDGING TO EDGE NORTHEAST INTO THE LOWER LAKES. MEANWHILE AT THE SURFACE...LINGERING WEAK TROUGHINESS ACROSS THE LOWER LAKES AT THE START OF THE DAY WILL ALSO SLIDE EASTWARD...GIVING WAY TO MODEST LOW LEVEL RIDGING DURING THE AFTERNOON. GIVEN THESE DEVELOPMENTS...EXPECT THAT MONDAY SHOULD LARGELY BE ANOTHER DRY AND HOT/HUMID DAY...WITH 850 MB TEMPS OF +16C/+17C AGAIN SUPPORTING WIDESPREAD HIGHS IN THE UPPER 80S/LOWER 90S GIVEN WHAT SHOULD BE A DECENT AMOUNT OF SUNSHINE. WHILE BOTH THE GFS AND ECMWF BOTH SPIT OUT SOME LIGHT QPF ACROSS THE AREA PRIOR TO THE DEPARTURE OF THE LOW LEVEL TROUGH...BELIEVE THAT THIS IS OVERDONE GIVEN ONLY WEAK LINGERING FORCING AND FAIRLY WARM MID LEVEL TEMPS...WHICH SHOULD HELP TO KEEP ANY PRECIP ISOLATED IN COVERAGE AT BEST. HAVE THEREFORE KEPT POPS AT THE VERY LOW END OF THE SLIGHT CHANCE RANGE OR BELOW ON MONDAY. MONDAY NIGHT...BROAD/FLAT UPPER RIDGING WILL REMAIN INTACT ACROSS MUCH OF THE AREA...WHILE A SLOW MOVING COLD FRONTAL BOUNDARY OVER CENTRAL ONTARIO PROVINCE SAGS SOUTHWARD INTO THE UPPER LAKES AND SOUTHERN ONTARIO. WHILE I CANNOT TOTALLY RULE OUT SOME ASSOCIATED ISOLATED CONVECTION SNEAKING INTO THE SAINT LAWRENCE VALLEY TOWARD DAYBREAK ON TUESDAY...IT DOES APPEAR THAT THE FRONT WILL REMAIN FAR ENOUGH TO OUR NORTH AND THAT WE WILL REMAIN CAPPED ENOUGH FOR MAINLY DRY WEATHER TO CONTINUE AREAWIDE. WITH NO AIRMASS CHANGE AND AN INCREASING SOUTHWESTERLY LOW LEVEL FLOW EXPECTED WITH TIME IN RESPONSE TO THE APPROACHING FRONT...EXPECT DOWNRIGHT SULTRY TEMPERATURES WITH OVERNIGHT LOWS RANGING FROM THE MID AND UPPER 60S ACROSS INTERIOR SECTIONS...TO THE LOWER 70S ACROSS THE LAKE PLAINS. ON TUESDAY...THE AFOREMENTIONED FRONT WILL CONTINUE TO SLOWLY SAG SOUTH TOWARD OUR REGION...WITH NOTABLE TIMING DIFFERENCES SEEN AMONGST THE VARIOUS GUIDANCE PACKAGES. THE 00Z NAM IS AN EXTREMELY FAST OUTLIER THAT BRINGS THE FRONT COMPLETELY THROUGH THE AREA BY THE END OF THE DAY...WHICH SEEMS HIGHLY UNLIKELY GIVEN ITS NEAR-PARALLEL ORIENTATION TO THE UPPER LEVEL FLOW...NOT TO MENTION THE PROPENSITY FOR SUCH BOUNDARIES TO GET HUNG UP ACROSS THE LOWER LAKES AT THIS TIME OF YEAR. FOR THIS REASON...HAVE COMPLETELY DISREGARDED THIS SOLUTION. OF THE REMAINING GUIDANCE...THE GFS REMAINS A BIT ON THE FASTER SIDE THOUGH NOT AS FAST AS ITS PREVIOUS RUNS...BRINGING THE BOUNDARY INTO NORTHERN NEW YORK/LAKE ONTARIO BY THE END OF THE DAY...WHICH IS CLOSE ENOUGH TO GENERATE SOME CONVECTION ACROSS BOTH THE NORTH COUNTRY AND NIAGARA/ORLEANS COUNTIES. MEANWHILE...THE VERY CONSISTENT ECMWF REMAINS A TOUCH SLOWER THAN THE GFS AND ONLY BRINGS A RISK OF CONVECTION INTO THE NORTH COUNTRY...WITH THE 00Z GEM GLOBAL A BIT SLOWER STILL. AT THIS JUNCTURE...FEEL A COMPROMISE BETWEEN THE GFS/ECMWF REPRESENTS THE MOST PLAUSIBLE SCENARIO...WHICH WOULD BRING AT LEAST A LOW TO MODEST CHANCE OF CONVECTION TO LAKE ONTARIO AND THE NORTH COUNTRY BY LATE IN THE DAY. FURTHER TO THE SOUTH...CONDITIONS SHOULD REMAIN DRY THROUGH THE DAY ON TUESDAY...THANKS TO BOTH GREATER DISTANCE FROM THE FRONT AND STRONG MID LEVEL CAPPING...AS EVEN HOTTER AIR RIDES EAST ALONG THE PERIPHERY OF THE MAIN UPPER LEVEL RIDGE. A CONSENSUS OF THE GFS/GEM/ECMWF SUPPORTS 850 MB TEMPS RISING TO THE +20/+21C RANGE AREAWIDE DURING THE COURSE OF TUESDAY...AND THIS COUPLED WITH GOOD MIXING AND A DECENT AMOUNT OF SUN WILL LIKELY RESULT IN A REAL SCORCHER OF A DAY SOUTH OF LAKE ONTARIO. AT THIS POINT...WIDESPREAD HIGHS IN THE LOWER TO MID 90S APPEAR TO BE A SOLID BET...WITH UPPER 90S NOT AT ALL OUT OF THE QUESTION FOR THE NORMAL HOT SPOTS IN INTERIOR PORTIONS OF OUR CWA. COUPLED WITH DEWPOINTS IN THE MID TO UPPER 60S...SOME LOCATIONS SOUTH OF LAKE ONTARIO COULD SEE APPARENT TEMPERATURES REACHING THE 100 DEGREE MARK TUESDAY AFTERNOON...WHICH WOULD NECESSITATE THE ISSUANCE OF A HEAT ADVISORY. AS IT REMAINS FAR TOO EARLY FOR THAT...FOR NOW WILL JUST MENTION THIS POTENTIAL IN THE HWO. EAST OF LAKE ONTARIO...SOMEWHAT GREATER AMOUNTS OF CLOUD COVER WILL LIKELY HELP KEEP TEMPS A LITTLE COOLER...THOUGH IT SHOULD STILL BE UNCOMFORTABLY HOT EVEN THERE WITH HIGHS IN THE UPPER 80S TO LOWER 90S. TUESDAY NIGHT AND WEDNESDAY...THE COLD FRONT WILL SLOWLY SAG SOUTH ACROSS THE REGION...BRINGING A RISK OF CONVECTION TO THE ENTIRE CWA...ALONG WITH THE POTENTIAL FOR LOCALLY HEAVY RAINFALL GIVEN PRECIPITABLE WATER VALUES IN THE VICINITY OF AROUND 2 INCHES. AT THIS JUNCTURE...THE TIMING OF THIS BOUNDARY REMAINS AN ISSUE WITH THE GFS REMAINING THE FASTEST...THE CANADIAN THE SLOWEST...AND THE ECMWF IN THE MIDDLE...WITH FROPA TIMES RANGING BETWEEN EARLY TO MID WEDNESDAY MORNING AND WEDNESDAY AFTERNOON. GIVEN THAT THIS FRONT APPEARS TO BE ANAFRONTAL WITH MOST OF ITS PRECIP FALLING BEHIND THE ACTUAL SURFACE BOUNDARY...THIS MEANS THAT ANY ASSOCIATED CONVECTION COULD END AS EARLY AS SOMETIME WEDNESDAY MORNING...OR AS LATE AS THE END OF THE DAY WEDNESDAY. GIVEN THE CONTINUED UNCERTAINTIES IN TIMING AND THE AFOREMENTIONED NEAR-PARALLEL ORIENTATION OF THE FRONT TO THE UPPER FLOW...FEEL IT IS BEST TO SLOW DOWN THE TIMING OF THIS FRONT AND ITS ASSOCIATED CONVECTION A BIT FROM THE PREVIOUS FORECAST...FAVORING A COMPROMISE SOLUTION ALONG THE LINES OF THE ECMWF. AS A RESULT...CHANCES FOR CONVECTION WILL BE IN PLACE FROM TUESDAY NIGHT THROUGH WEDNESDAY MORNING ACROSS THE ENTIRE AREA...BEFORE DIMINISHING FROM NORTH TO SOUTH DURING THE COURSE OF WEDNESDAY AFTERNOON. TEMPERATURE-WISE... EXPECT ANOTHER SULTRY NIGHT IN ADVANCE OF THE FRONT TUESDAY NIGHT WITH LOWS AGAIN RANGING FROM THE UPPER 60S TO LOWER 70S...FOLLOWED BY SOMEWHAT COOLER HIGHS IN THE UPPER 70S TO MID 80S ON WEDNESDAY GIVEN THE PASSAGE OF THE FRONT AND ITS ASSOCIATED CLOUD COVER/PRECIP. && .LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/... SIMPLY PUT...SPRAWLING CANADIAN HIGH PRESSURE WILL BUILD SOUTHEAST ACROSS THE GREAT LAKES AND NORTHEAST DURING THIS PERIOD...BRINGING A RETURN TO DRY WEATHER ALONG WITH A COOLER AND NOTICEABLY LESS HUMID AIRMASS. IN TERMS OF ACTUAL TEMPERATURES...EXPECT DAILY HIGHS TO FALL BACK INTO THE MID 70S TO LOWER 80S FOR BOTH THURSDAY AND FRIDAY...BEFORE WARMING BACK INTO THE LOWER TO MID 80S ON SATURDAY AS WARMING COMMENCES ALOFT. MEANWHILE...NIGHTTIME LOWS WILL RANGE IN THE MID 50S TO LOWER 60S ALL THREE NIGHTS. HUMIDITY LEVELS WILL ALSO BE MUCH MORE COMFORTABLE...WITH DEWPOINTS REMAINING IN THE MID TO UPPER 50S DURING THE BULK OF THE PERIOD. && .AVIATION /12Z SUNDAY THROUGH THURSDAY/... AN AREA OF SHOWERS AND THUNDERSTORMS WILL MOVE ACROSS THE REGION THROUGH MID-AFTERNOON. RADAR TRENDS SUGGEST MOST WIDESPREAD SHOWERS WILL BE BETWEEN 15Z AND 21Z...WITH EMBEDDED THUNDERSTORM ACTIVITY LIKELY. OUTSIDE OF THESE...EXPECT MAINLY VFR CONDITIONS. SHOWERS AND THUNDERSTORMS MAY LOWER VSBY TO 2SM AT TIMES IN HEAVY RAINFALL. AFTERWARD...EXPECT A GENERAL CLEARING TREND FROM WEST TO EAST LATE THIS AFTERNOON AND EVENING. THIS SHOULD RESULT IN MAINLY VFR CONDITIONS...BUT THERE WILL BE AN INCREASING CHANCE FOR FOG OVERNIGHT. THE COMBINATION OF LIGHT WINDS AND LINGERING BOUNDARY LAYER MOISTURE MAY RESULT IN FAIRLY WIDESPREAD FOG. WINDS MAY LIMIT HOW LOW VSBY DROPS AT BUF/IAG/ROC/ART...BUT DENSE FOG MAY DEVELOP AT JHW...IN A RELATIVELY LIGHT FLOW. OUTLOOK... MONDAY AND TUESDAY...MAINLY VFR. TUESDAY NIGHT...AREAS OF MVFR IN SCATTERED -SHRA/-TSRA. WEDNESDAY...BECOMING VFR. THURSDAY...VFR. && .MARINE... HIGH PRESSURE WILL REMAIN ANCHORED ALONG THE MID ATLANTIC COAST THROUGH EARLY NEXT WEEK. MEANWHILE A WEAK TROUGH WILL APPROACH THE LOWER LAKES TODAY AND ALLOW SOUTHWEST WINDS TO INCREASE SOMEWHAT TO THE 10-15 KNOT RANGE...WITH THE STRONGEST WINDS ON LAKE ERIE. EXPECT CONDITIONS TO REMAIN BELOW SMALL CRAFT CRITERIA...BUT WAVES MAY GET A LITTLE CHOPPY ON LAKE ERIE. A RIDGE OF HIGH PRESSURE WILL NOSE INTO THE LOWER LAKES MONDAY WITH RELATIVELY LIGHT WINDS. SOUTHWEST WINDS WILL PICK UP AGAIN TUESDAY AHEAD OF A STRONGER COLD FRONT...ESPECIALLY ON LAKE ERIE WHERE CONDITIONS MAY APPROACH SMALL CRAFT ADVISORY CRITERIA. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...NONE. MARINE...NONE. && $$ SYNOPSIS...APFFEL NEAR TERM...APFFEL SHORT TERM...JJR LONG TERM...JJR AVIATION...APFFEL MARINE...APFFEL/JJR
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1013 AM CDT SUN JUL 15 2012 .DISCUSSION... SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ALONG THE COAST MOVING NORTHEAST. THESE HAVE PRODUCED GUSTS OF 20-27 KTS AND .77" OF RAIN AT GLS. 00Z/06Z MODELS DID A VERY POOR JOB IN RESOLVING THESE STORMS AS WELL AS THE TEXAS TECH WRF/4KM NAT WRF THOUGH THE RUC HAS DONE A MARGINAL JOB BUT WITH TOO MUCH CONVECTION OVER THE GULF. WATER VAPOR HAS A SMALL CYCLONIC CIRCULATION EMBEDDED IN THE MOIST AXIS JUST WEST OF MATAGORDA BAY. AREA SOUNDINGS AND ACARS SOUNDINGS INDICATE THAT CONVECTIVE TEMPS OF 82 TO 85 SHOULD BE SUFFICIENT FOR FURTHER DEVELOPMENT. HAVE RAISED POPS IN THE SOUTH AND NORTHEAST FOR THE SHORT TERM TRENDS THIS MORNING AND IN THE WEST FOR THE AFTERNOON AS VORT LIFTS NORTH AND SPEED DIVERGENCE ALOFT HAS SOME ADDITIONAL LIFT. SHEAR AXIS CONTINUES TO MOVE WEST AND THIS TO SHOULD HELP TO DESTABILIZE THE WESTERN AREAS THIS AFTERNOON. STILL WORRIED ABOUT THE MOIST AXIS ACROSS THE CENTRAL GULF AND OVER LA...WV CONTINUES TO CLEARLY DEPICT THE WESTWARD PROGRESSION...COULD MAKE FOR A WET MONDAY/TUESDAY. 45 && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 91 73 92 74 93 / 40 20 30 20 30 HOUSTON (IAH) 90 74 91 75 92 / 40 20 30 10 30 GALVESTON (GLS) 88 81 90 81 90 / 40 20 30 20 30 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ DISCUSSION...45
AREA FORECAST DISCUSSION
NWS TAUNTON MA
206 PM EDT SUN JUL 15 2012 .SYNOPSIS... HOT AND HUMID WEATHER WILL CONTINUE TODAY WITH SCATTERED THUNDERSTORMS...ESPECIALLY IN WESTERN NEW ENGLAND AS A WEAK COLD FRONT APPROACHES THE REGION. HEAT AND HUMIDITY WILL BE WITH US THROUGH WEDNESDAY...WHEN A STRONGER COLD FRONT MAY BRING ANOTHER ROUND OF THUNDERSTORMS. HIGH PRESSURE WILL DOMINATE OUR WEATHER THURSDAY INTO THE START OF NEXT WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 2 PM UPDATE... SHOWERS/SCT TSTMS INCREASING IN COVERAGE ACROSS SE NY AND MOVING EAST. ACTIVITY IS MOVING INTO A FAVORABLE ENVIRONMENT WITH MLCAPES 1000-1500 J/KG ACROSS SW NEW ENG SO EXPECT CONVECTION TO MOVE INTO THE REGION NEXT 1-2 HOURS...AND HRRR INDICATING INCREASING SHOWERS/ISOLD TSTMS 19-21Z. MID LEVEL LAPSE RATES AND DEEP LAYER SHEAR ARE WEAK WHICH WILL LIMIT SEVERE WX POTENTIAL...BUT CANT RULE OUT A STRONG STORM AND HEAVY RAINFALL WILL BE A CONCERN GIVEN HIGH PWAT AIRMASS. PREVIOUS DISCUSSION... MID LEVEL TROF ACROSS GT LAKES WITH WV IMAGERY SHOWING MULTIPLE SHORTWAVES MOVING THROUGH THE FLOW. MAIN IMPULSE ACROSS MI BUT LEAD SHORTWAVE ACROSS W NY WILL BE LIFTING NE ACROSS CENTRAL NEW ENG LATER THIS AFTERNOON WHICH SHOULD PROVIDE A TRIGGER FOR CONVECTION TO DEVELOP. THERE ARE A FEW SHOWERS ACROSS E NY WHICH MAY AFFECT PORTIONS OF W NEW ENG EARLY THIS AFTERNOON...BUT MAIN FOCUS FOR STRONGER TSTMS SHOULD BE MID TO LATE AFTERNOON ACROSS W ZONES AND EXTENDING INTO THE EVENING FURTHER E AS DEEPER MOISTURE AND MID LEVEL OMEGA APPROACHES FROM THE WEST. CAPES ARE FORECAST TO INCREASE TO 1000-2000 J/KG...BUT MID LEVEL LAPSE RATES ARE WEAK AND DEEP LAYER SHEAR IS MARGINAL. STILL...IF FORECAST INSTABILITY CAN BE REALIZED A FEW STRONG TO SEVERE STORMS WILL BE POSSIBLE GIVEN 0-6KM SHEAR 25-30 KT. PWATS INCREASE OVER 2" BY LATE TODAY SO ANY STORMS WILL ALSO HAVE THE POTENTIAL TO PRODUCE VERY HEAVY RAINFALL. HIGHEST POPS THIS AFTERNOON WILL BE FOCUSED ACROSS W ZONES WITH LOWEST POPS E NEW ENG WHERE MOST OF THE DAY SHOULD REMAIN DRY. MID/HIGH CLOUDS ARE ADVANCING ACROSS W NEW ENG AND SUNSHINE WILL GRADUALLY FADE AS CLOUDS INCREASE FROM WEST TO EAST. TEMPS ALREADY IN THE LOW/MID 80S ACROSS MUCH OF THE REGION. WARMEST TEMPS WITH SOME LOWER 90S POSSIBLE WILL BE ACROSS INTERIOR E MA AND SE NH WHERE MOST SUNSHINE...BUT INCREASING CLOUD COVER WILL SLOW TEMP RISE ACROSS W NEW ENG. DEWPOINTS WILL BE CLIMBING TO 70+ DURING THE AFTERNOON SO VERY HUMID. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/... KEPT LIKELY POPS EARLY TONIGHT ACROSS INTERIOR AS WE EXPECT ACTIVITY TO SLOWLY DIMINISH WITH LOSS OF DAYTIME HEATING. 00Z GFS IS MORE EMPHATIC THAT STRONGER SURFACE LOW WILL FORM ALONG FRONT WHICH RESULTS IN MORE WIDESPREAD RAINFALL TONIGHT. NOT SURE THAT WILL BE CASE GIVEN RATHER FLAT MID LEVEL TROUGH SO PREFER TO LEAN MORE TOWARD DRIER NAM/SREF SOLUTION WHICH GIVES CHANCE POPS CLOSER TO COAST. SHOULD SEE PARTIAL CLEARING AND DRIER AIR WORK ITS WAY INTO REGION TOWARD DAYBREAK. FRONT WILL SETTLE NEAR S COAST MON AND EVENTUALLY WASHES OUT. ALTHOUGH CROSS SECTIONS SHOW DRYING THROUGH COLUMN...THERE MAY BE ENOUGH LEFTOVER MOISTURE COMBINED WITH WEAK SURFACE CONVERGENCE TO PRODUCE AN ISOLATED SHOWER OR THUNDERSTORM ALONG S COAST MON AFTERNOON. NOT MUCH CHANGE IN AIRMASS BEHIND FRONT SO HIGHS SHOULD ONCE AGAIN TOP OUT IN 80S AND LOWER 90S...ALTHOUGH HUMIDITY WILL BE LOWER. && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... HIGHLIGHTS...SHORTWAVE RACES EAST OF THE AREA MONDAY...THEN A DEEPER MID-LEVEL TROUGH APPROACHES FOR WEDNESDAY AND THURSDAY. A MID- LEVEL RIDGE SHOULD BUILD OVER THE CENTRAL USA DURING THE LATTER HALF OF NEXT WEEK. THIS WILL COMPLICATE OUR FORECAST AS THE DOWNSTREAM MID-LEVEL TROUGH COULD ALSO AMPLIFY AND RETROGRADE BACK OVER NEW ENGLAND IF IT DOES NOT REMAIN PROGRESSIVE. SURFACE HIGH PRESSURE SITS OFFSHORE THROUGH THE EXTENDED PERIOD WITH A SOUTHWEST FLOW INTO SOUTHERN NEW ENGLAND UNTIL WEDNESDAY. THIS WILL MEAN HEAT AND HUMIDITY INTO MIDWEEK. MONDAY NIGHT-TUESDAY... SHORTWAVE MOVES OFF TO THE EAST MONDAY MORNING WITH BUILDING HEIGHTS OVER NEW ENGLAND. MODELS CONTINUE TO SHOW SURFACE PRESSURE FIELDS HINTING AT A LEE TROUGH ALONG THE NORTHEAST CORRIDOR. MODELS CONTINUE TO INDICATE MARGINALLY FAVORABLE CONVECTIVE PARAMETERS DURING THIS PERIOD. HOWEVER...THE SOUNDINGS LOOK TO BE TOO DRY OVER TOO DEEP A LAYER TO REALLY SUPPORT SCATTERED TO WIDESPREAD CONVECTION. HAVE KEPT THIS PORTION OF THE FORECAST DRY. WEDNESDAY... A COLD FRONT MOVES THROUGH AND PROVIDES A FOCUS FOR SCATTERED SHOWERS/TSTMS. THURSDAY-FRIDAY... COLD FRONT MOVES OFFSHORE EARLY...WITH HIGH PRESSURE BUILDING THROUGH THE PERIOD. THE CHANGE TO A NORTHWEST WIND WILL USHER IN DRIER AIR. SATURDAY... HIGH PRESSURE CENTER BEGINS TO MOVE OFFSHORE BUT STILL LOOKS LIKE IT WILL BE PREDOMINANT WEATHER FEATURE FOR OUR AREA. DRY FCST. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT MODERATE...30 PERCENT TO 60 PERCENT HIGH...GREATER THAN 60 PERCENT OVERVIEW...MODERATE CONFIDENCE. SHOWERS/SCT TSTMS WILL MOVE EAST ACROSS THE REGION LATE AFTERNOON THROUGH THIS EVENING AND WILL LIKELY BE ACCOMPANIED BY A PERIOD OF MVFR/IFR CONDITIONS. AFTER THE SHOWERS MOVE TO THE EAST OVERNIGHT...AREAS OF STRATUS AND FOG WILL LIKELY DEVELOP THEN IMPROVING TO VFR DURING MON MORNING. LOW PROB OF AN ISOLD SHOWER/TSTM DEVELOPING MON AFTERNOON. KBOS TAF...MODERATE CONFIDENCE. EXPECT SHOWERS AND A FEW TSTMS...MAINLY AFT 00Z WITH A PERIOD OF MVFR CONDITIONS DEVELOPING. SHOWERS MOVE TO THE EAST AFTER MIDNIGHT...BUT AREAS OF MVFR CIGS/VSBYS MAY DEVELOP...IMPROVING AFT 12Z. LOW PROB OF A SEABREEZE MON AFTERNOON. KBDL TAF...MODERATE CONFIDENCE. SHOWERS AND A FEW TSTMS EXPECTED 21-03Z WITH AREAS OF MVFR...THEN IMPROVING TO VFR OVERNIGHT. OUTLOOK...TUESDAY THROUGH THURSDAY... TUESDAY...MODERATE CONFIDENCE PATCHY FOG/LOW CLOUDS DURING THE MORNING WITH IFR/LIFR CONDITIONS. BEST CHANCE WILL BE IN THE CT VALLEY AND ALONG THE SOUTH COAST. WEDNESDAY...MODERATE CONFIDENCE COLD FRONT APPROACHES DURING THE DAY. IFR/LIFR POSSIBLE IN EARLY MORNING FOG/LOW CLOUDS...THEN VFR DURING THE DAY EXCEPT FOR PASSAGE OF TSTMS. ANY SHOWERS/TSTMS THAT DEVELOP MAY BRING A PERIOD OF MVFR/IFR MAINLY IN THE AFTERNOON/EVENING. THURSDAY...MODERATE CONFIDENCE HIGH PRESSURE BUILDS IN FROM THE NORTHWEST...VFR. && .MARINE... HIGH CONFIDENCE THROUGH MON WITH NO HEADLINES ANTICIPATED. S/SW FLOW EXPECTED TODAY AHEAD OF WEAKENING COLD FRONT. SCATTERED SHOWERS OR THUNDERSTORMS ARE POSSIBLE TOWARD EVENING...BEFORE AREAS OF FOG DEVELOP IN MOIST AIRMASS. FRONT SHOULD WASH OUT NEAR S COAST MON MORNING AND MAY BECOME FOCUS FOR AN ISOLATED SHOWER OR THUNDERSTORM MON AFTERNOON AS FLOW REMAINS S/SW. SEAS WILL SLOWLY BUILD ON S COASTAL WATERS THROUGH MON BUT SHOULD NOT GET HIGHER THAN 4 FT S OF ISLANDS. OUTLOOK...TUESDAY THROUGH THURSDAY MODERATE CONFIDENCE DUE TO TIMING OF A COLD FRONT WEDNESDAY. THIS WILL IMPACT THE STRENGTH OF THE SOUTHWEST FLOW. SEAS SHOULD DIMINISH TUESDAY. INCREASING HUMIDITY IS EXPECTED WITH DEW POINTS AROUND 70 MONDAY THROUGH WEDNESDAY. THIS COULD MEAN AREAS OF FOG FOR THE LATE NIGHT AND EARLY MORNING PERIODS. SEAS BUILD AGAIN TUESDAY NIGHT AND WEDNESDAY AHEAD OF AN APPROACHING COLD FRONT...LOW RISK OF 5 FOOT SEAS ACROSS THE SOUTHERN OUTER COASTAL WATERS. THIS FRONT IS EXPECTED TO BRING SCATTERED SHOWERS AND THUNDERSTORMS WEDNESDAY INTO WEDNESDAY NIGHT. SEAS THEN SUBSIDE SOMEWHAT FOR THURSDAY. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...NONE. && $$ SYNOPSIS...BELK/JWD NEAR TERM...KJC SHORT TERM...JWD LONG TERM...BELK AVIATION...BELK/KJC MARINE...BELK/JWD
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
345 PM EDT Sun Jul 15 2012 .NEAR TERM [through Tonight]... While the dry mid-upper troposphere will help limit the overall coverage and intensity of deep moist convection through this evening, there will be enough boundary layer moisture and influx of moisture from the Atlantic for scattered, "more shallow" convection. The greatest rain chance will be east of Tallahassee and Albany, where a combination of the FL/GA east coast sea breeze front, boundary layer moisture, and instability will be enough to support a 40-50% chance of rain. So far cloud-ground lightning and surface wind gusts have been on the low side with the cells to our east, and this will likely continue. One or two cells could become briefly strong (with wind gusts to 40 MPH and brief heavy rain), but the chance of severe storms (58 MPH+ and/or large hail) is low. Most of the rain over land will diminish shortly after sunset, but scattered showers and storms will likely persist over the Gulf coastal waters as the sea breeze translates westward. Low tonight will be typical for this time of year, in the lower to mid 70s. && .SHORT TERM [Monday through Tuesday Night]... The forecast for the early part of the week will be influenced by the progression of a TUTT ("Tropical Upper Tropospheric Trough") and TUTT low currently situated to the east of the area. The TUTT low is very well defined on water vapor loops this afternoon, spinning near 31.2N / 78.2W. The upper level trough extends SW from there over S FL and towards the Yucatan. The TUTT low, and associated trough, are expected to slowly drift to the west over the next couple days, with the low near GNV by Monday afternoon, and near Apalachee Bay by Tuesday afternoon. The question is how fast the aforementioned pocket of mid-upper level dry air will be eroded by the approaching trough. The GFS and RUC both indicate that should occur overnight, with PWATS reaching values much closer to climatological normals by Monday. So far this weekend, a lot of the convection has been situated near or east of the TUTT axis, which means that it could take until Tuesday for a notable increase in PoPs across the entire area. Therefore, for Monday we expect more isolated activity (20-30% PoPs) in the NW half of the area, with scattered to numerous storms (45-60% PoPs) around the Florida Big Bend near Apalachee Bay. By Tuesday, we will be more underneath the TUTT axis, and the low-level flow pattern will be transitioning from light and variable to southerly. Therefore, the increased forcing for ascent in the mid and upper levels, as well as the local sea-breeze climatology both favor higher PoPs over the entire area. PoPs were bumped up to about 50% in most areas. There are some hints that the atmosphere could become a little more favorable for downbursts in stronger storms in the short term period as well, but this remains uncertain. .LONG TERM [Wednesday through Sunday]... Very little change to the extended fcst this cycle as the latest 00 UTC GFS and ECMWF have remained in fairly good agreement with a Synoptic pattern dominated by a TUTT Low which will gradually open up into an Upper Level Trof. This should further increase fcst confidence in above Climo Pops and near Climo Max Temps through much of the period. Despite the fairly disturbed pattern, the MEX High Temps appeared too high (Mid 90s in many areas away from the coast) for the expected levels of cloud cover and rain chances, so used a 2-1 Blend of the lower and more realistic looking HPC and MOS Guidance grids. The Euro (and GFS to some extent) do both show some potential for a brief break in this pattern on Friday, with possible Upper Level Ridging moving in from the east, before the mean Trof builds back southward over the weekend, bringing a return to higher rain chances. && .AVIATION... [through 18z Monday] KECP and KVLD are likely to be only terminals affected by TSRA/SHRA today, with brief IFR-MVFR vis/cigs and gusty winds through late afternoon or early evening. The PoP is too low elsewhere to include in this afternoon`s TAF package. Some of the high resolution NWP indicate the potential for low clouds/fog around KVLD early Monday morning, but our confidence is not yet high enough to include this in the forecast. && .MARINE... Very benign weather pattern for the marine forecast in terms of winds and seas. Weak surface pressure pattern should keep winds at or below 10 knots, and seas should therefore be 2 feet or less. The approaching upper level low for Monday and Tuesday may begin to increase thunderstorm coverage over the waters early this week, particularly during the overnight and early morning hours. && .FIRE WEATHER... Relative humidity levels are unlikely to reach critical values for the next several days. This, along with near-climo rain chances (40-50%) over the next several days, will make controlled burning difficult. && .PRELIMINARY POINT TEMPS/POPS... Tallahassee 73 92 73 91 74 / 30 50 20 50 30 Panama City 75 91 76 88 76 / 20 30 20 30 30 Dothan 74 95 75 93 74 / 20 30 20 50 30 Albany 72 95 74 94 74 / 20 30 20 50 40 Valdosta 71 93 71 92 72 / 30 40 20 50 40 Cross City 71 91 72 89 72 / 50 50 20 50 30 Apalachicola 75 89 76 87 76 / 20 40 20 30 20 && .TAE WATCHES/WARNINGS/ADVISORIES... AL...None. GA...None. FL...None. MARINE...None. && $$ Near Term...Fournier Short Term...Lamers Long Term...Gould Aviation...Fournier Marine...Lamers Fire Weather...Fournier
AREA FORECAST DISCUSSION
NWS JACKSON KY
225 PM EDT SUN JUL 15 2012 .UPDATE... ISSUED AT 225 PM EDT SUN JUL 15 2012 COVERAGE HAS PICKED UP ALONG AND SOUTH OF THE HAL ROGERS PARKWAY AND HIGHWAY 80 CORRIDORS THANKS TO BUILDING INSTABILITY AS WELL AS AN OUTFLOW BOUNDARY MOVING EAST SOUTHEAST ACROSS THE AREA. HAVE BEEFED UP THE POPS DOWN SOUTH ALL THE WAY TO THE PORTIONS OF THE VIRGINIA BORDER AS CONVECTION WILL LIKELY KEEP POPPING AS THE OUTFLOW BOUNDARY CONTINUES TO MOVE THROUGH SOUTHEAST KENTUCKY. HAVE REDUCED POPS FURTHER NORTH TO JUST SCATTERED AS THE UPPER LEVEL FORCING GRADUALLY LESSENS. ISSUED 1054 AM EDT SUN JUL 15 2012 SHOWERS CONTINUE TO FOCUS ALONG THE NORTHWEST PORTION OF THE CWA THIS MORNING...AS A LOW LEVEL JET ALONG WITH SOME UPPER LEVEL DIVERGENCE REMAIN IN PLACE NEAR THE OHIO RIVER. SOME OF THE HEAVIER SHOWERS AND ISOLATED THUNDERSTORMS HAVE BEEN DROPPING A LOT OF RAIN IN A SHORT PERIOD OF TIME...UP TO AN INCH IN LESS THAN 30 MINUTES. FORTUNATELY...STORM MOTIONS ARE AROUND 15 KTS...HOWEVER WILL HAVE TO MONITOR AT LEAST A FEW LOCATIONS FOR REPEATED ROUNDS...WHICH COULD LEAD TO MINOR FLOODING IN LOW LYING AREAS AT A MINIMUM. HAVE INCREASED POPS UP TO CATEGORICAL GIVEN THE RADAR TRENDS. THE LATEST NAM SHOWS ACTIVITY PEAKING IN THE 15-18Z TIME FRAME AND THEN SCATTERING OUT MORE FOR THE REST OF THE AFTERNOON AS SOME MID- LEVEL CAPPING DEVELOPS. THIS IS SIMILAR TO THE 06Z RUN...SO IT MAY BE ON TO SOMETHING. THE LAST RUN OF THE SREF CONTINUES THE HIGHER POPS THROUGH 21Z AND THIS MAY ALSO BE A CONTENDER WITH ANY OUTFLOW BOUNDARY INTERACTION. FOR NOW...WILL LEAN TOWARDS THE NAM IDEA. FRESHENED UP THE REST OF THE GRIDS...MAINLY TO ALLOW FOR A FASTER DIURNAL RISE WHERE CLOUDS ARE STARTING OUT THINNER. HIGHS RANGING FROM THE LOWER 80S IN THE NORTH TO A FEW UPPER 80S IN THE SOUTHEAST LOOK ON TARGET. UPDATE ISSUED AT 700 AM EDT SUN JUL 15 2012 SHOWERS HAVE INCREASED OVER ERN KY THIS MORNING WITH A FEW RUMBLES AS WELL...LENDING SOME CREDIBILITY TO THE HRRR AND NAM12...AND HAVE BENT THE GRIDS IN THIS DIRECTION THROUGH THE REMAINDER OF THE MORNING. ALSO UPDATED SKY...ALONG WITH TEMPS AND DEW PTS TO ESTABLISH TRENDS HEADING INTO THE DAY. OTHERWISE...THE FCST IS ESSENTIALLY ON TRACK. UPDATED ZONES WILL BE ISSUED SHORTLY. && .SHORT TERM...(TODAY THROUGH MONDAY) ISSUED AT 232 AM EDT SUN JUL 15 2012 ESSENTIALLY LOOKING AT A PERSISTENCE FORECAST FOR TODAY AND TONIGHT WITH LITTLE CHANGE ANTICIPATED IN THE OVERALL. THE QUESTION REMAINS WHERE AND WHEN CONVECTION WILL INITIATE...BUT THE NEAR TERM MODELS ARE STILL PLUGGING SOME EARLY MORNING DEVELOPMENT OVER CNTRL TN AND KY SPREADING EAST THROUGH THE MORNING AND CONTINUING THROUGH THE AFTERNOON BEFORE DIMINISHING THIS EVENING FOLLOWING THE LOSS OF DAYTIME HEATING. MODELS ARE IN GENERAL AGREEMENT IN DEVELOPING SOME HEALTHY INSTABILITY THIS MORNING...UPWARDS OF 3K J/KG MU CAPE AGAIN WITH CONVECTIVE TEMPS IN THE LOWER 80S AND CURRENT FCST HIGHS IN THE MID 80S. FCST PWATS CONTINUE TO RUN ABOUT 2 INCHES THROUGHOUT THE DAY...AND WITH A RIGHT ENTRANCE REGION OF A MODEST 50-60KT UPPER LEVEL JET TRAVERSING UP THE OHIO VALLEY THIS AFTERNOON...COUPLED WITH A MID LEVEL SHORT WAVE MOVING UP FROM THE TN VALLEY...CAN SEE LITTLE REASON THIS MORNING WHY WE WOULD NOT SEE SOME EFFICIENT TSTMS AGAIN LATER THIS MORNING CONTINUING THROUGH THE AFTERNOON...WITH LOCALLY HEAVY RAINFALL AGAIN THE PRIMARY CONCERN. MONDAY IS LOOKING A LITTLE MORE INTERESTING THIS MORNING WITH FCST SOUNDINGS DEPICTING A STRONGER CAP DEVELOPING BY LATE MORNING CONTINUING THROUGH THE PEAK HEATING HOURS AS THE STRONG BERMUDA HIGH IS PROGGED TO SHIFT WEST TOWARDS THE CENTRAL APPALACHIANS...WEAKENING SLIGHTLY IN THE PROCESS. DRIER...BUT WARMER MID LEVEL ADVECTION WILL EITHER SQUASH PRECIP CHANCES OR...IF THE CAP BREAKS...COULD RESULT IN SOME STRONG STORMS AGAIN DEVELOPING DURING THE AFTERNOON WITH DAMAGING WINDS POSSIBLE IN ADDITION TO THE THREAT FOR LOCALLY HEAVY RAINFALL. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 232 AM EDT SUN JUL 15 2012 THE MODELS ARE IN PRETTY GOOD AGREEMENT WITH THE GENERAL LONG WAVE PATTERN...HOWEVER THERE ARE SOME DIFFERENCES IN THE TIMING SOME OF THE SHORT WAVES LATER ON DURING THE PERIOD. ON MONDAY NIGHT...KENTUCKY WILL BE DOMINATED BY THE UPPER RIDGE WITH A MAJOR TROUGH JUST OFF THE WEST COAST. ALL THE FRONTAL ACTIVITY WILL BE WELL NORTH OF THE AREA AND THE COAL FIELDS WILL BE DOMINATED BY THE WARM...MOIST AND UNSTABLE AIR MASS. WITH TIME...AN UPPER TROUGH BEGINS TO DROP SOUTH FROM AN UPPER LOW CENTER OVER THE CANADIAN MARITIMES. THIS WILL ALLOW A COLD FRONT TO START MOVING TO THE SOUTH. BY THURSDAY MORNING...THE FRONT WILL BE OVER NORTHERN KENTUCKY AND WILL SLOWLY MOVE SOUTH DURING THE DAY. BY FRIDAY MORNING THE FRONT WILL HAVE MOVED INTO CENTRAL TENNESSEE. THE 00GMT GFS IS WANTING TO SLOW THE FRONT DOWN AND SORT OF STALL IT OVER THE AREA ON FRIDAY...WHILE THE 12 GMT ECMWF WANTS TO MOVES IT SOUTH OF THE AREA MORE QUICKLY. IN GENERAL...I HAVE MORE CONFIDENCE IN THE ECMWF AND WILL BE NUDGING THE FORECAST TOWARD THE FASTER FRONTAL PASSAGE. IN EITHER CASE...AS THE FRONT MOVES TO THE SOUTH...DRIER AIR WILL BE MOVING INTO THE AREA AND MAKE THINGS MORE COMFORTABLE. EVEN THOUGH THE HIGHS WILL STILL BE A LITTLE ABOVE NORMAL. THE OVERNIGHT LOWS WILL DROP DUE TO THE DRIER AIR. IN THE MEAN TIME...KENTUCKY WILL BE UNDER A DIRTY RIDGE WITH WARM MOIST UNSTABLE AIR OVER THE AREA WHICH WILL BE ABLE TO PRODUCE MAINLY AFTERNOON AND EVENING CONVECTIVE THUNDERSTORMS AND SHOWERS AND WILL KEEP TEMPERATURES WARM AND MISERABLE. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 225 PM EDT SUN JUL 15 2012 SCATTERED TO NUMEROUS CONVECTION IS POPPING ACROSS THE AREA...PARTICULARLY ALONG AND SOUTH OF THE HAL ROGERS PARKWAY AND HIGHWAY 80 CORRIDORS. LOZ LOOKS TO SEE THE BEST CHANCE OF SEEING A DIRECT HIT FROM THUNDERSTORMS AND HAVE INCLUDED A TEMPO BETWEEN 19 AND 21Z. HAVE HELD ONTO VCTS ELSEWHERE. FOG WILL AGAIN BE A CONCERN TONIGHT AND HAVE GONE IFR AT MOST LOCATIONS...ALTHOUGH LIFR OR WORSE IN LOCATIONS THAT HAVE SEEN THE HEAVIER RAIN SHOWERS IS LIKELY. ONCE THE FOG BURNS OFF MONDAY MORNING...CONVECTION WILL LIKELY THREATEN ONCE AGAIN...ALTHOUGH THIS MAY BE A BIT LATER IN THE DAY THAN WE HAVE SEEN COMPARED TO THE LAST SEVERAL DAYS SO HAVE LEFT OUT ANY MENTION FOR NOW. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...GEOGERIAN SHORT TERM...MB LONG TERM....JJ AVIATION...GEOGERIAN
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
145 PM EDT SUN JUL 15 2012 .UPDATE... ISSUED AT 1119 AM EDT SUN JUL 15 2012 MORNING UPDATE MAINLY DEALS WITH TWEAKS TO THE FOG OVER LK SUPERIOR AND CLOUD COVER THIS AFTN OVER INTERIOR LOCATIONS. FOR THE FOG...EXTENDED THE DENSE FOG ADVY FOR NORTHERN AREAS THROUGH THIS AFTN DUE TO RECENT WEBCAMS ALONG THE NRN KEWEENAW SHORELINE SHOWING DENSE FOG AT THIS HOUR. FARTHER SOUTH AND EAST...WEBCAMS AND SHIP OBS THIS MORNING SHOWING THE EXPANSE OF CLOUDS OVER THE SE LK SUPERIOR MAINLY IN THE FORM OF LOW STRATUS. THUS...WILL LET THAT ADVY EXPIRE AT NOON. HIGH RES MODELS ARE ALL SHOWING DIURNAL CU AND LIGHT SHOWERS DEVELOPING OVER THE WRN/CNTRL CWA AWAY FROM THE LK BREEZES OFF LK SUPERIOR. AREAS FROM WRN LK SUPERIOR TO THE THUNDER BAY AND N SAW SOME SCATTERED ACCAS EARLY THIS MORNING...WHICH SEEMS TO BE JUST E OF THE VERY DRY AIR ON THE 12Z KINL SOUNDING. BUT WITH THE SLOW LLVL WINDS NOT PUSHING THE DRY AIR E VERY QUICKLY...THINKING THE LINGERING LLVL MOISTURE WILL BE ENOUGH TO DEVELOP A LARGER AREA OF CU THAN PREVIOUSLY THOUGHT. THEREFORE...BUMPED SKIES UP TO PARTLY CLOUDY FOR MUCH OF THE INTERIOR W AND CNTRL. SINCE WEAK SHORTWAVE ENERGY WILL TRY TO WORK INTO THE AREA THIS AFTN FROM MORNING SHOWERS IN NW MN...THAT MAY BE ENOUGH TO HELP PRODUCE AN ISOLATED SHOWER OR TWO. WITH ALL OF THE HIGH RES MODELS AND THE NEW 12Z NAM KICKING OFF SHOWERS...EVEN THOUGH THEY MAY BE OVERDOING THE LLVL TD VALUES SOME...WILL INTRODUCE THEM AROUND 18Z OVER ERN ONTONAGON/GOGEBIC COUNTIES AND THEN DRIFT SE BEFORE DIMINISHING IN THE LATE AFTN. SINCE THERE APPEARS TO BE PLENTY OF DRY AIR ABOVE H750...WILL KEEP THUNDER MENTION OUT AS THIS WILL LIKELY LIMIT CLOUD DEPTH TO A FEW KFT AND MAY EVEN HOLD OFF SHOWER DEVELOPMENT. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 520 AM EDT SUN JUL 15 2012 WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW TROF JUST E OF THE FCST AREA. SHRA/TSRA THAT ACCOMPANIED THE TROF ACROSS THE AREA YESTERDAY HAVE RECENTLY EXITED THE SE PORTION OF THE FCST AREA. IN ITS WAKE... CALM WIND/CLEARING SKIES AND MOISTURE FROM YESTERDAY`S RAINFALL HAS LED TO SOME FOG DEVELOPMENT. FOG WILL QUICKLY BURN OFF WITHIN A COUPLE HRS AFTER SUNRISE. UPSTREAM...A MID LEVEL RIDGE IS NOSING INTO THE DAKOTAS/WRN MN. AS THE RIDGE SHIFTS E TODAY...UPPER MI WILL FALL UNDER HEIGHT RISES/DEEP LAYER QVECTOR DIVERGENCE. MUCH DRIER AIR...MAINLY IN THE MID LEVELS PER UPSTREAM 00Z KINL/CWPL SOUNDINGS...WILL WORK AGAINST ANY AFTN CONVECTIVE DEVELOPMENT DESPITE LAKE BREEZES PROVIDING LOW-LEVEL FORCING. THE K-INDEX ON THE 00Z CWPL/KINL SOUNDINGS WAS -11/-14C RESPECTIVELY DUE TO VERY DRY AIR AROUND 700MB (DWPT DEPRESSIONS WERE IN EXCESS OF 40C). SO... GOING DRY FCST APPEARS ON TRACK DESPITE SOME HIGH RES GUIDANCE CONTINUING TO SHOW ISOLD CONVECTION OVER THE SCNTRL THIS AFTN. MIXING TO AROUND 800MB ON FCST SOUNDINGS SUPPORTS MAX TEMPS UPWARDS OF AROUND 90F. LIGHT GRADIENT WIND WILL ALLOW LAKE BREEZES OFF LAKE SUPERIOR AND LAKE MICHIGAN TO PROVIDE SOME COOLING LAKESIDE. SHORTWAVE ENERGY EJECTING FROM THE TROF CURRENTLY OVER THE WRN STATES WILL HEAD INTO SCNTRL CANADA TONIGHT. IN RESPONSE...LOW-LEVEL JET WILL INCREASE TO 45-50KT INTO THE NRN PLAINS. THIS WILL LIKELY SUPPORT A CLUSTER OF SHRA/TSRA ON THE NOSE OF THE LOW-LEVEL JET AND ALONG EDGE OF CAP ACROSS ND INTO SRN MANITOBA/NRN MN AND NRN ONTARIO. AT THIS TIME...IT STILL APPEARS LOW-LEVEL JET WILL BE W OF THE AREA AT 12Z MON...SO DO NOT ANTICIPATE ANY CONVECTION LATE TONIGHT...EXCEPT POSSIBLY OVER NW LAKE SUPERIOR/ISLE ROYALE. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 520 AM EDT SUN JUL 15 2012 BY 12Z MONDAY THE FRONTAL BOUNDARY WOULD BE ACROSS LAKE SUPERIOR /AS A WARM FRONT/...STRETCHING FROM THE SFC LOW SET UP FROM NW MN TO CENTRAL SD. DEPENDING ON THE AMOUNT OF MIXING /UP TO AROUND 800MB AT SAW/ A FEW GUSTS OF 30 TO 35KTS COULD BE POSSIBLE FROM LATE MORNING THROUGH THE REMAINDER OF THE DAYTIME HOURS. IF CLOUD COVER DOES NOT INHIBIT MIXING...THESE STRONGER GUSTS COULD BE POSSIBLE ACROSS THE DOWNSLOPE LOCATIONS NEAR LAKE SUPERIOR GIVEN THE STRENGTHENING SW FLOW. AS FOR THE OFFICIAL FCST...HAVE INCREASED WINDS QUITE A BIT FROM THE PREVIOUS FORECAST...WITH GUSTS OF 20-25KTS ACROSS MUCH OF THE CWA BY MID AFTERNOON. THE RECORD HIGH TEMP FOR MONDAY AT WFO MQT IS 95 DEGREES...WHICH MAY BE BROKEN BY THE END OF THE DAY. CURRENTLY GOING ONLY A COUPLE OF DEGREES COOLER THAN THIS RECORD...WITH 850MB TEMPS OF 22-24C ALLOWING SEVERAL SITES ACROSS THE INTERIOR W HALF OF UPPER MI REACHING 95 OR ABOVE. THE SFC LOW SHOULD PUSH ACROSS THE AREA MONDAY AFTERNOON THROUGH TUESDAY NIGHT. THE TRACK IS STILL UNCERTAIN...WITH THE 14/18Z GFS AND 15/00Z NAM PUSHING THE SFC LOW ACROSS THE KEWEENAW PENINSULA AND ACROSS LAKE SUPERIOR BY EARLY MONDAY EVENING. THE FARTHER SOUTH 14/12Z ECMWF INDICATES A BROADER LOW...STRETCHING ACROSS CENTRAL AND SOUTHERN UPPER MI MONDAY NIGHT. THE 14/12Z CANADIAN IS BEYOND CONSENSUS FROM MONDAY AFTERNOON ON...TRACKING THE SFC LOW ACROSS ONTARIO AND N LAKE SUPERIOR...AND WILL NOT BE USED IN THIS FORECAST UNTIL IT MOVES BACK IN LINE WITH THE REMAINDER OF AVAILABLE GUIDANCE WEDNESDAY MORNING. HIGH PRESSURE OVER CENTRAL CANADA TUESDAY MORNING WILL SLOWLY SHIFT SE ACROSS LAKE SUPERIOR AND UPPER MI TUESDAY THROUGH THURSDAY. THE COOLEST AFTERNOON TEMPS LOOK TO BE WEDNESDAY...TOPPING OUT IN THE 70S...COOLEST NEAR LAKE SUPERIOR AS DRY COOL AIR REMAINS. 850MB TEMPS WEDNESDAY WILL BE A COOL 10-12C. THE FCST FOR THE CWA WILL REMAIN DRY TUESDAY NIGHT THROUGH FRIDAY NIGHT. EXPECT THE SFC HIGH TO DRIFT E TO THE LOWER GREAT LAKES AND W QUEBEC BY DAYBREAK FRIDAY AND THE NEW ENGLAND COAST FRIDAY NIGHT...WITH A RIDGE REMAINING ACROSS THE UPPER GREAT LAKES REGION. A RELATIVELY WEAK SFC LOW STRETCHING FROM CENTRAL CANADA THROUGH THE CENTRAL PLAINS LOOKS TO BECOME BETTER ORGANIZED TO OUR W SATURDAY NIGHT...AS A SERIES OF DISTURBANCES NEAR FROM W AND CENTRAL CANADA AS 500MB RIDGE BECOMES SUPPRESSED ACROSS THE CENTRAL AND SOUTHERN PLAINS. KEPT CHANCE POPS FOR SATURDAY...ALTHOUGH CONFIDENCE IS MODERATE TO LOW FOR SPECIFICS THAT FAR OUT IN THIS FCST. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 144 PM EDT SUN JUL 15 2012 MAINLY VFR CONDITIONS THROUGH THE PERIOD...AS THE DEVELOPING WARM FRONT TONIGHT IS EXPECTED TO STAY TO THE N OF THE AREA. THEREFORE...ALL OF THE ASSOCIATED CONVECTION SHOULD REMAIN OVER NRN LK SUPERIOR OR SRN ONTARIO. HAVE SOME CONCERN WITH FOG/STRATUS OVER LK SUPERIOR AND IT/S POSSIBLE EFFECT ON KCMX/KIWD. CURRENT THINKING IS THAT IT SHOULDN/T AFFECT KIWD DO TO INCREASING SWRLY FLOW TONIGHT. KCMX ON THE OTHERHAND IS TRICKY. WITH WINDS BECOMING ERLY THIS EVENING AND LOSS OF DIURNAL HEATING...COULD SEE THE FOG/STRATUS OVER LK SUPERIOR MOVE IN AND QUICKLY BRING CIGS/VSBYS DONE. INDICATIONS ARE THAT IT IS A STRATUS DECK...BUT THE LIGHT UPSLOPE FLOW WOULD HELP VSBYS GO DOWN. DON/T HAVE ENOUGH CONFIDENCE TO HIT THE LOW CLOUDS/VSBYS HARD...SO WILL MENTION OF MVFR VSBY AND SCT003 FOR NOW...BUT THINKING THAT WILL LIKELY NEED TO BE DROPPED TO ALT LANDING MINS. FINALLY...COULD GET QUITE GUSTY...TO 35KTS...OUT OF THE SSW AT THE END OF THE TAF PERIOD AND FOR THE REST OF THE AFTN TOMORROW FOR KIWD AND POTENTIALLY KCMX. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 520 AM EDT SUN JUL 15 2012 BIGGEST CONCERN IN THE SHORT TERM WILL BE FOG. 11-3.9MICRON SATELLITE IMAGERY INDICATES FOG (PROBABLY NOT STRATUS) EXPANDING S AND E FROM NCNTRL LAKE SUPERIOR. MORE FOG MAY BE DEVELOPING FROM KEWEENAW BAY TOWARD MARQUETTE/MUNISING. WITH DEVELOPING MESO HIGH PRES OVER THE LAKE TODAY...IT`S QUITE POSSIBLE FOG MAY END UP SPREADING TO THE SHORELINES AROUND THE ENTIRE LAKE TODAY. ALWAYS DIFFICULT TO FCST MARINE FOG...SO TRENDS WILL NEED TO MONITORED CLOSELY TODAY FOR MOVEMENT/DEVELOPMENT/DISSIPATION OF FOG. ONCE DAYLIGHT ARRIVES...VIS SATELLITE IMAGERY WILL PROVIDE A BETTER LOOK AT HOW THE FOG IS EVOLVING. QUITE POSSIBLE DENSE FOG ADVY MAY NEED TO BE ISSUED. FOR NOW...CARRIED FOG MENTION THRU EARLY AFTN OVER MAINLY CNTRL AND ERN LAKE SUPERIOR. OTHERWISE...WITH HIGH PRES DEVELOPING OVER LAKE SUPERIOR TODAY... WINDS WILL BE UNDER 15KT. ALTHOUGH WINDS WILL BECOME S-SE TONIGHT IN ADVANCE OF APPROACHING LOW PRES...SPEEDS SHOULD REMAIN 15KT OR LESS. THERE IS SOME UNCERTAINTY IN WHERE WARM FRONT ASSOCIATED WITH THE LOW WILL BE POSITIONED MON. AT THIS TIME...IT APPEARS THAT AT LEAST SRN PORTIONS OF THE LAKE WILL SEE INCREASING S-SW WINDS MON UPWARDS OF 20KT AS WARM FRONT DRIFTS N. AS LOW PASSES ACROSS THE AREA MON NIGHT...A COLD FRONT WILL PUSH S...BRINGING A SHIFT TO NORTHERLY WINDS UPWARDS OF 20KT INTO TUE MORNING. HIGH PRES WILL THEN BUILD INTO THE UPPER GREAT LAKES DURING THE MIDWEEK PERIOD...RESULTING IN WINDS UNDER 20KT. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... DENSE FOG ADVISORY UNTIL 6 PM EDT THIS EVENING FOR LSZ243>245- 263-264-266. LAKE MICHIGAN... NONE. && $$ UPDATE...SRF SHORT TERM...ROLFSON LONG TERM...KF AVIATION...SRF MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS GLASGOW MT
312 PM MDT SUN JUL 15 2012 .SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH TUESDAY... WATER VAPOR IMAGERY SHOWS AN UPPER LEVEL LOW OVER THE PACIFIC NORTHWEST WHICH CONTINUE TO MOVE SOUTHWARD OVER THE WEST COAST BEFORE BECOMING STATIONARY SOMEWHERE NEAR THE NORTHERN CALIFORNIA COAST LINE BY THE END OF THE SHORT TERM PERIOD. THIS WILL LEAVE MONTANA IN AN OVER ALL SW FLOW ALOFT PATTERN. THIS WILL CONTINUE THE FEEDING OF PACIFIC MOISTURE FOR THE NEXT FEW DAYS ALONG WITH DISTURBANCES MOVING OVER MONTANA CAUGHT IN THIS FLOW.FOR THUNDERSTORMS ACROSS THE CENTRAL AND NORTHERN ROCKIES OVERNIGHT LAST NIGHT AND TODAY. SO LOOKING AT THE FORECAST FOR LATE THIS AFTERNOON AND THIS EVENING THE CHANCE OF SHOWERS AND THUNDERSTORMS IS POSSIBLE. THE WATER VAPOR IMAGERY SHOWS TWO JET STREAKS...ONE MOVING INTO SW MONTANA AND ONE MOVING INTO SW WYOMING WHICH SHOULD HELP AID IN THUNDERSTORM DEVELOPMENT ACROSS CENTRAL AND EASTERN MONTANA LATE THIS AFTERNOON AND EVENING. THUNDERSTORMS THAT ARE ALREADY THERE COULD BE ENHANCED BY THE LEFT FRONT ENTRANCE REGION OF THE JET STREAK ACROSS SW WYOMING ONCE IT GETS CLOSE TO CENTRAL MONTANA LATE THIS EVENING. THE LATEST HRRR MODELS SHOWS CONVECTION DEVELOPING ACROSS CENTRAL MONTANA AND MOVING EASTWARD INTO NORTHEAST MONTANA THIS EVENING. SO DECIDED TO INCREASE POPS AND MENTION BRIEF MODERATE RAINFALL ALONG WITH POSSIBLE GUSTY WINDS. THE CHANCE OF THUNDERSTORMS WILL END AFTER MIDNIGHT BUT REDEVELOP MONDAY AFTERNOON AS ANOTHER SHORTWAVE MOVE UP IN THE SW FLOW FROM THE NORTHERN GREAT BASIN. THIS WAVE SEEMS TO GET STUCK OVER CENTRAL MONTANA BEFORE GETTING PUSHED NE TUESDAY EVENING. SHOULD PROVIDE ENOUGH LIFT AND INSTABILITY TO CONTINUE CHANCE TO SLIGHT CHANCE POPS ACROSS THE REGION THROUGH THE SAME TIME FRAME. NO SEVERE WEATHER IS EXPECT DURING THIS TIME FRAME BUT A FEW STRONG THUNDERSTORMS CELL ARE POSSIBLE. SPC HAS A GENERAL THUNDERSTORM RISK FOR MONDAY AND WE ARE PROBABLY LOOKING AT THE SAME THING FOR TUESDAY. HIGHS ACROSS THE REGION BOTH MONDAY AND TUESDAY WILL BE IN THE UPPER 80S AND LOWER 90S. CLOUD COVER WILL PLAY BIG FACTOR IN THE TEMPERATURE FORECAST MORE ON TUESDAY RATHER THEN MONDAY. RSMITH .LONG TERM...TUESDAY NIGHT THROUGH SUNDAY... AFTERNOON UPDATE...THE ONLY REAL CHANGE TO THE EXTENDED FORECAST IS TO ADD SOME POPS INTO THE FORECAST IN THE FRIDAY INTO SATURDAY TIME FRAME. A SURFACE TROF SETS UP OVER THE EASTERN MT AND ND BORDER WITH A SOUTHWEST FLOW ALOFT WHICH GENERALLY ALLOWS FOR SOME THUNDERSTORMS TO FORM. NO BIG EVENT EXPECTED AT THIS TIME JUST GENERAL THUNDERSTORMS. OTHERWISE TUESDAY NIGHT INTO WEDNESDAY NIGHT IS THE EVENT OF INTEREST IN THE EXTENDED AND HAVE INCREASED POPS A BIT ALONG THE CANADIAN BORDER AND NORTH DAKOTA BORDER AREAS. FRANSEN SOUTHWEST FLOW ALOFT WILL BE OVER MONTANA THROUGH FRIDAY AND NOW ARE A DAY LATER WITH MOVING THE WEST COAST UPPER TROUGH INLAND (FRIDAY NIGHT VERSUS THURSDAY NIGHT). WITHIN THE SOUTHWEST FLOW ALOFT...A SHORTWAVE TUESDAY NIGHT INTO WEDNESDAY WILL BRING A CHANCE OF SHOWERS AND THUNDERSTORMS TO THE FORECAST AREA. THEN THE RIDGE OVER THE CENTRAL U.S. STRENGTHENS AND WARMS TEMPERATURES INTO THE 90S FOR MOST OF THE AREA FOR THURSDAY AND FRIDAY. DRIER AIRMASS WILL ALSO LIMIT PRECIP CHANCES ALTHOUGH WEAK WAVES COULD BRING A SHOWER OR THUNDERSTORM WEDNESDAY NIGHT AND THURSDAY. THE UPPER TROUGH MOVES INLAND FRIDAY AND THROUGH THE FORECAST AREA FRIDAY NIGHT. WITH LIMITED MOISTURE...WILL MENTION A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS FOR NOW. THE WAVE WILL FLATTEN THE RIDGE SO THAT THE FLOW ALOFT BECOMES ZONAL FOR NEXT WEEKEND WITH DRY WEATHER. FORRESTER && .AVIATION... LOOK FOR VFR CONDITIONS TODAY AND TONIGHT WITH A MIX AND MID AND HIGH LEVEL CLOUDS. MAY SEE SOME WIDELY SCATTERED SHOWERS OR THUNDERSTORMS AFFECT THE TAF SITES BTWN 21Z THROUGH 05Z. EAST TO SOUTHEAST WINDS EARLY THIS MORNING WILL DIMINISH AND TURN TO THE WEST OR WEST- NORTHWEST AROUND 10 KTS AS A LOW PRESSURE SYSTEM MOVES FROM EASTERN MT INTO WESTERN ND. FRANSEN && .GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE. && $$ WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
300 PM CDT SUN JUL 15 2012 .SHORT TERM... THE MAIN CHALLENGES WILL BE CONVECTIVE CHANCES LATE THIS AFTERNOON AND OVERNIGHT...ALONG WITH TEMPS AND RESULTANT HEAT INDICES THROUGH MONDAY IN THE SOUTH. MODELS CONTINUE TO DIFFER IN REGARDS TO WARM FRONTAL PLACEMENT AND CONVECTION...WITH THE GFS STILL TOO FAR SOUTH WITH THE NAM PERHAPS TOO FAR NORTH. THE ECMWF REMAINS A DECENT COMPROMISE ALTHOUGH IT IS MORE IN THE NORTHERLY NAM CAMP. THE LATEST NEAR TERM HRRR AND OTHER MESOSCALE MODELS ARE ALSO IN AGREEMENT WITH THE CAP HOLDING INTO THIS EVENT WITH A MORE NORTHERLY MCS OVERNIGHT...SO WILL BASE POPS ON THIS SCENARIO. FOR TONIGHT...EXPECT CONVECTION TO DEVELOP SOMEWHERE IN NC ND TO THE WEST OF THE FORECAST AREA AROUND OR SHORTLY BEFORE 00Z. STORM MOTION VECTORS AND INCREASE LLJ WILL LIKELY CAUSE THESE STORMS TO TRACK NEAR THE CANADIAN BORDER THEN TURN INTO NE ND/NW MN OVERNIGHT. THERE WILL BE AMPLE SHEAR/INSTABILITY FOR A FEW SEVERE STORMS...AND GIVEN A VERY PRONOUNCED WARM FRONT AND HIGH SHEAR...CAN/T RULE OUT A TORNADO EITHER IF DEWPOINTS CAN POOL ENOUGH LOCALLY. IT STILL IS UNCERTAIN HOW CURRENT CAP WILL AFFECT CONVECTION THOUGH...BUT POTENTIAL EXISTS FOR SEVERE STORMS SO WILL MENTION OVERNIGHT. IT WILL BE VERY MILD OVERNIGHT...WITH THE SOUTH REMAINING IN THE 70S. FOR MON...THE FRONT WILL SAG INTO THE SOUTH BUT IT WILL REMAIN VERY WARM HERE. HEAT INDICES WILL RISE TO AROUND 100...AND WE MAY NEED SOME HEAT HEADLINES HERE. FOR NOW WILL HOLD ON HEADLINES WITH UNCERTAINTY IN REGARDS TO CLOUD COVER/DEWPOINTS BUT SOMETHING TO KEEP IN MIND FOR LATER SHIFTS. THERE WILL BE THE CHANCE FOR SHOWERS OR STORMS BUT MOST AREAS WILL REMAIN DRY. ON TUE/WED...EXPECTING A COUPLE OF DRY DAYS WITH TEMPS NEAR NORMAL AND HIGH PRESSURE BUILDING IN. THERE COULD BE A THREAT FOR SOME CONVECTION IN THE FAR SOUTH...BUT FEEL ITS NOT WORTH A MENTION BUT SOMETHING TO KEEP IN MIND. .LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY GFS/ECMWF IN POOR AGREEMENT WEDNESDAY THROUGH NEXT WEEKEND... BECOMING 180 DEGREES OUT OF PHASE ACROSS THE NORTHERN PLAINS BY 00 UTC SATURDAY WITH RESPECT TO THE 500 HPA HEIGHT PATTERN. DESPITE ALLBLEND POPS OF 20 TO 30 PERCENT NEARLY EVERY PERIOD...WILL FOLLOW PREVIOUS FORECAST CLOSELY TO MAINTAIN CONTINUITY. GIVEN RECENT SYNOPTIC REGIME...PREFER THE HOTTER AND DRIER ECMWF SOLUTION. BEST AGREEMENT BETWEEN GFS/ECMWF FOR PRECIPITATION IS WEDNESDAY NIGHT INTO THURSDAY AS A WEAK SHORT-WAVE MAY MOVE THROUGH RIDGE ALOFT. ALSO INCLUDED LOW POPS FRIDAY NIGHT INTO SATURDAY ON THE OFF-CHANCE THE OVERLY AGGRESSIVE GFS VERIFIES WITH ANOTHER WAVE MOVING ALONG THE CANADIAN BORDER. TEMPERATURES EXPECTED TO INCREASE SLIGHTLY EACH DAY...WITH MANY LOCATIONS BACK IN THE 90S BY FRIDAY/SATURDAY. OVERNIGHT LOWS MAY ALSO BE VERY WARM BY WEEK/S END...AT OR ABOVE 70 DEGREES. && .AVIATION... EXPECT VFR CONDITIONS THROUGH 18 UTC MONDAY. LATE THIS AFTERNOON AND EVENING...SHOWERS AND THUNDERSTORMS WILL DEVELOP ALONG AND NORTH OF A WARM FRONT STRETCHING ALONG THE HIGHWAY 2 CORRIDOR. WITH THE EXCEPTION OF KDVL...THINK CONVECTION WILL REMAIN NORTH OF TAF SITES...SO KEPT 18 UTC ISSUANCE DRY AT THIS TIME. WILL NEED TO WATCH KGFK AND KTVF FOR POSSIBLE DEVELOPMENT FARTHER SOUTH. WINDS SOUTH OF THE FRONT WILL CONTINUE FROM THE SOUTHEAST...GUSTING TO 25 KTS AT TIMES. NORTH OF THE FRONT...WINDS WILL BE FROM THE EAST-NORTHEAST. LATE TONIGHT...WINDS WILL SHIFT TO THE NORTHWEST AFTER SURFACE TROUGH PASSAGE. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ DK/ROGERS
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
333 PM CDT SUN JUL 15 2012 .DISCUSSION... CURRENTLY...UPPER LEVEL RIDING IS PUSHING BACK INTO THE REGION FROM THE EAST WHICH HAS PUSHED THE MOISTURE AXIS THAT CONTAINS PWAT VALUES GREATER THAN 2 INCHES TO THE WESTERN HALF OF THE MIDSOUTH. AN OUTFLOW BOUNDARY PUSHING NORTH INTO NW MS IS PRODUCING SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS WITH ISOLATED TO SCATTERED CONVECTION ACROSS EASTERN ARKANSAS AND THE MO BOOTHEEL. DRIER AIR WORKING INTO THE EASTERN HALF HAS SEVERELY LIMITED AREAL COVERAGE EAST OF MEMPHIS FOR NOW. TEMPS ARE GENERALLY IN THE MID AND UPPER 80S THOUGH A FEW READINGS ABOVE 90 CAN BE FOUND ACROSS NE MS AND SE PARTS OF WEST TN. TONIGHT...BEST CHANCES FOR SHOWERS AND THUNDERSTORMS WILL CONTINUE TO BE ACROSS THE WESTERN HALF OF THE MIDSOUTH THROUGH EARLY EVENING WITH LESS COVERAGE TO THE EAST. SOME OF STORMS WILL CONTAIN VERY HEAVY RAINFALL AND GUSTY WINDS. CONVECTION IS MAINLY SURFACE HEATING BASED SO ACTIVITY WILL DISSIPATE QUICKLY THIS EVENING AND THIS IS CONFIRMED NICELY BY THE LATEST HRRR RUN. TEMPS WILL BE SIMILAR TO THE PAST SEVERAL NIGHT WITH LOWS IN THE 70 TO 75 DEGREE RANGE. MONDAY THROUGH WEDNESDAY...UPPER RIDGE WILL BE OVER THE AREA AND TEMPS WILL START TO HEAT UP INTO THE MID 90S BY TUESDAY AND WEDNESDAY. SURFACE DEWPOINTS SHOULD REMAIN IN AT LEAST THE LOWER 70S WHICH MAY PRODUCE HEAT INDEX VALUES NEAR ADVISORY LEVELS BY MIDWEEK. EVEN WITH THE UPPER RIDGE OVER THE AREA THE MID LEVEL CAPPING WILL NOT BE STRONG ENOUGH TO COMPLETELY SHUT OFF CONVECTION...THOUGH AREAL COVERAGE WILL BE LOWER AS PWAT VALUES FALL. OVERNIGHT LOWS WILL BE TRENDING UP AS WELL. THURSDAY THROUGH SUNDAY...UPPER RIDGE MAY WEAKEN SLIGHTLY AS AN UPPER TROF MOVING THROUGH THE NORTHEAST/EASTERN GREAT LAKES SENDS A BACK DOOR COLD FRONT INTO THE OHIO VALLEY. 12Z MODELS ARE NOT IN VERY GOOD AGREEMENT ATTM. THE 12Z GFS LEANS TOWARD MORE UPPER LEVEL RIDGING. MEANWHILE THE ECMWF DEVELOPS A CLOSED 500 MB LOW OVER THE EASTERN OHIO VALLEY BY SUNDAY AFTERNOON. HAVE GENERALLY GONE WITH A COMPROMISE BETWEEN THE COOLER/WETTER ECMWF AND THE WARMER/DRIER GFS. SJM && .AVIATION... 18Z TAF CYCLE CIGS AND VSBYS AT ALL TAF SITES HAVE BECOME VFR AND SHOULD REMAIN SO THROUGH LATE THIS EVENING. PWATS REMAIN IN EXCESS OF 2 INCHES AT ALL SURROUNDING 12Z SOUNDING LOCATIONS (KJAN...KLZK...KOHX) WITH THE EXCEPTION BEING KBMX WHERE DRIER AIR HAS WORKED IN WITH PWATS AROUND 1.45 INCHES DUE TO RIDGING ALOFT SPREADING WESTWARD. PLAN TO CARRY VCTS AT ALL SITES FOR THIS AFTERNOON...BUT KEEP TEMPOS AT ALL SITES EXCEPT KTUP WHERE DRIER AIRMASS MAY WORK IN. THE HIGHEST CONVECTIVE POTENTIAL SHOULD REMAIN ALONG AND WEST OF THE MISSISSIPPI RIVER TO INCLUDE KMEM AND KJBR. IN FACT...A PROMINANT OUTFLOW BOUNDARY CURRENTLY OVER THE DELTA COUNTIES OF NORTH CENTRAL MISSISSIPPI SHOULD CONTINUE TO PUSH NORTH TOWARDS KMEM LATER THIS AFTERNOON AND MAY FOCUS CONVECTIVE ACTIVITY. TEMPO AT KMEM MAY NEED TO BE EXTENDED BEYOND CURRENT EXPIRATION OF 15/22Z. CONVECTION SHOULD WANE IN COVERAGE AND INTENSITY LATER THIS EVENING WITH MOST LOCATIONS RAIN FREE AFTER 16/02Z. LOWER CIGS SHOULD ONCE AGAIN OCCUR IN MOST LOCATIONS LATE TONIGHT WITH AT LEAST REDUCTIONS TO MVFR. THERE MAY EVEN BE IFR CIGS AT SOME LOCATIONS BUT CONFIDENCE NOT HIGH ENOUGH TO INCLUDE IN THE LATEST TAF. THERE MAY ALSO BE SOME MVFR VSBYS IN PATCHY FOG. LOW CLOUDS SHOULD MIX OUT BY LATER MONDAY MORNING WITH MOST LOCATIONS BECOMING VFR NEAR THE END OF THE TAF FORECAST PERIOD. CONVECTIVE POTENTIAL APPEARS LOWER TOMORROW AS THE PERSISTENT UPPER TROUGH AXIS BEGINS TO SHIFT NORTHWEST AND UPPER RIDGING BUILDS FROM THE SOUTHEAST. JLH && .PRELIMINARY POINT TEMPS/POPS... MEM 75 93 76 95 / 20 30 10 20 MKL 71 93 72 94 / 20 30 10 20 JBR 73 93 74 95 / 20 20 10 20 TUP 73 94 74 94 / 20 20 10 30 && .MEG WATCHES/WARNINGS/ADVISORIES... AR...NONE. MO...NONE. MS...NONE. TN...NONE. && $$
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1235 PM CDT SUN JUL 15 2012 .AVIATION... 18Z TAFS THROUGH 20Z...CARRYING SHRA/TSRA FOR IAH AND CXO AND UTS. GENERALLY WENT WITH VCSH ELSEWHERE BUT WILL HAVE TO WATCH FOR ADDITIONAL AFTERNOON DEVELOPMENT OUT WEST WHERE CONVECTIVE TEMPERATURES ARE PROBABLY GOING TO BE REACHED AGAIN (ALREADY SEEING REDEVELOPMENT IN/AROUND THE MATAGORDA BAY AREA). VFR OVERNIGHT WITH LIGHT WINDS. LEANING TOWARD WETTER MODEL SOLUTIONS FOR TOMORROW...SO INTRODUCED VCSH TOWARD THE COAST IN THE MORNING AND VCTS FURTHER INLAND IN THE AFTER4NOON. GOOD COORDINATION CALL WITH CWSU ZHU. 42 && .PREV DISCUSSION... /ISSUED 1013 AM CDT SUN JUL 15 2012/ DISCUSSION... SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ALONG THE COAST MOVING NORTHEAST. THESE HAVE PRODUCED GUSTS OF 20-27 KTS AND .77" OF RAIN AT GLS. 00Z/06Z MODELS DID A VERY POOR JOB IN RESOLVING THESE STORMS AS WELL AS THE TEXAS TECH WRF/4KM NAT WRF THOUGH THE RUC HAS DONE A MARGINAL JOB BUT WITH TOO MUCH CONVECTION OVER THE GULF. WATER VAPOR HAS A SMALL CYCLONIC CIRCULATION EMBEDDED IN THE MOIST AXIS JUST WEST OF MATAGORDA BAY. AREA SOUNDINGS AND ACARS SOUNDINGS INDICATE THAT CONVECTIVE TEMPS OF 82 TO 85 SHOULD BE SUFFICIENT FOR FURTHER DEVELOPMENT. HAVE RAISED POPS IN THE SOUTH AND NORTHEAST FOR THE SHORT TERM TRENDS THIS MORNING AND IN THE WEST FOR THE AFTERNOON AS VORT LIFTS NORTH AND SPEED DIVERGENCE ALOFT HAS SOME ADDITIONAL LIFT. SHEAR AXIS CONTINUES TO MOVE WEST AND THIS TO SHOULD HELP TO DESTABILIZE THE WESTERN AREAS THIS AFTERNOON. STILL WORRIED ABOUT THE MOIST AXIS ACROSS THE CENTRAL GULF AND OVER LA...WV CONTINUES TO CLEARLY DEPICT THE WESTWARD PROGRESSION...COULD MAKE FOR A WET MONDAY/TUESDAY. 45 && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 73 92 74 93 74 / 20 30 20 30 20 HOUSTON (IAH) 74 91 75 92 76 / 20 30 10 30 20 GALVESTON (GLS) 81 90 81 90 81 / 20 30 20 30 30 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ DISCUSSION...45 AVIATION/MARINE...42
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
236 PM CDT SUN JUL 15 2012 .SHORT TERM...TONIGHT AND MONDAY. LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW LOW PRESSURE CENTERED ON THE MONTANA-NORTH DAKOTA BORDER AND ITS ASSOCIATED WARM FRONT EXTENDING ACROSS THE DAKOTAS. YESTERDAYS UPPER TROUGH HAS MOVED TO THE EASTERN GREAT LAKES. WISCONSIN LIES BETWEEN THESE TWO FEATURES IN A REGION OF BUILDING HEIGHTS ALOFT. DIURNAL CU HAS POPPED OVER CENTRAL AND NORTH-CENTRAL WISCONSIN AND AREA RADARS HAVE DETECTED A SOLE SPRINKLE THAT DEVELOPED EARLIER OVER THE PORTAGE/WAUPACA BORDER. THE CU LOOKS RATHER FEISTY SO WILL ADD AN ISOLATED SPRINKLE MENTION FOR THE REST OF THE AFTERNOON. AS THE MID-LEVEL RIDGE BUILDS INTO OUR AREA...THE MAIN FORECAST CONCERNS INCLUDE CLOUDS AND TEMPS INCLUDING HEAT HEADLINES OVER THE NEXT 24 HOURS. TONIGHT...LOW PRESSURE WILL MOVE NE OVER THE NORTHERN PLAINS AND HIGH PRESSURE WILL REMAIN CENTERED OVER THE SE CONUS. UPSTREAM MID-DECK AND CIRRUS WILL LIKELY MAKE IT AT LEAST OVER THE NORTHERN HALF OF THE FORECAST AREA TONIGHT AND LIGHT AND VARIABLE WINDS AT THE SURFACE WILL PICK UP LATE. THESE CONDITIONS POINT TOWARDS A WARMER NIGHT AND WILL GO WITH LOWS RANGING THROUGH THE 60S. MONDAY...UPSTREAM LOW PRESSURE WILL MOVE EAST OVER NORTHERN MINNESOTA AND WESTERN LAKE SUPERIOR. AS THIS OCCURS...A COLD FRONT WILL SAG INTO NORTHWEST WISCONSIN LATE IN THE DAY...BUT AIRMASS AHEAD OF THE FRONT IS PRETTY DRY...SO THINKING THERE IS SLIM CHANCES OF A COOLING THUNDERSTORM. WILL LEAVE A SLIGHT CHANCE OVER FAR NORTHERN VILAS IN CASE A ROGUE STORM DECIDES TO MAKE A RUN TOWARDS THE NORTHERN TIP OF THE COUNTY. OTHERWISE...THE HEAT WILL BE THE MAIN STORY TOMORROW. THE LATEST GUIDANCE SHOWS 850MB TEMPS IN THE 24-25C RANGE WHICH WOULD PUT HIGHS NEAR 100F. A TIGHTENING PRESSURE GRADIENT WILL SUPPORT GOOD MIXING GREATER THAN 800MB...AND HELP TO MIX OUT DEWPOINTS INTO THE LOW TO MID 60S. BUT THE GOOD MIXING ALSO SUPPORTS GOING ON THE WARM SIDE OF GUIDANCE...WHICH PLACES HIGHS IN THE MID TO UPPER 90S OVER CENTRAL AND EAST-CENTRAL WISCONSIN...AND LOW TO MID 90S FARTHER NORTH. SOME 100S WILL LIKELY BE REACHED IN THE HOT SPOTS AROUND WAUPACA AND WAUSHARA. ONLY CONCERN WITH TEMPS IS THE MID AND HIGH LEVEL MOISTURE UPSTREAM...THOUGH ITS TOUGH TO GAUGE HOW THICK IT WILL BE TOMORROW. BECAUSE DEWPOINTS WILL LIKELY BE MIXING OUT...THINK HEAT INDICES MAY STRUGGLE TO REACH ADVISORY CRITERIA OVER CENTRAL WISCONSIN. NONETHELESS...NO POINT IN CANCELLING HEADLINES AT THIS POINT AS POTENTIAL WILL STILL BE THERE AND IT WILL BE VERY HOT. .LONG TERM...MONDAY NIGHT THROUGH NEXT SUNDAY. CONTINUE TO DEAL WITH FLUCTUATIONS IN POSITION/STRENGTH OF STRONG CENTRAL U.S. RIDGE WITH SYSTEMS EJECTING OUT OF WESTERN TROF THROUGH CANADA. TEMPERATURES EXPECTED TO START OUT WARM...THEN RETURN TO NEAR NORMAL LEVELS BEFORE HEATING UP AGAIN ON THE WEEKEND. INITIALLY WILL BE DEALING WITH COOL FRONT MOVING INTO/THROUGH CWA MONDAY NIGHT AND TUESDAY. MAIN FORCING WITH UPPER JET REMAINS OVER THE NORTH...PULLS OUT TUE NIGHT. SOME INSTABILITY...THOUGH LIMITED. NAM STRONGER WITH SURFACE LOW...FASTER WITH FRONT PASSING...AND SHOWS DRY FRONTAL PASSAGE. EC ON SLOWER END OF GUIDANCE WITH SYSTEM AND FOR PAST TWO RUNS SUGGESTS MCS/S MAY MOVE ALONG FRONT TUE NIGHT/WED OVER SOUTHERN HALF OF STATE. NOT SEEING ANY SIG FORCING FOR SCENARIO...EXCEPT FOR SOME RELATIVELY WEAK WAA OVER MN/SD. FEW TEMPS/HEAT INDICES REACH ADVISORY LEVELS TUE AFTN OVER THE SOUTH...BUT WILL NOT EXTEND CURRENT ADVISORY GIVEN CLOUD/PCPN CONCERNS. CWA REMAINS ON EDGE OF SEE TEXT BY SPC FOR MONDAY NIGHT INTO TUE NIGHT. SHEAR IS LIMITED...THOUGH COULD SEE SOME GUSTY WINDS AND MARGINAL HAIL WITH SOME TO THE STORMS IF THEY DEVELOP. FRONT WILL SAG SOUTH INTO NORTHERN ILLINOIS ON WEDNESDAY WITH DRY CANADIAN HIGH PRESSURE MOVING IN FOR WED-FRI PERIOD. SPREAD SEEN IN ENSEMBLES FOR THE WEEKEND...WITH RIDGE POSITION/STRENGTH...THOUGH MEANS SUGGEST GOING ON THE WARM SIDE. && .AVIATION...FOR 12Z TAF ISSUANCE. AFTER FG BURNS OFF EARLY TDA... VFR CONDITIONS EXPECTED. SOME FG POSSIBLE AGAIN TNGT...BUT IT WL BE MUCH MORE PATCHY AND PROBABLY NOT OF A CONSEQUENCE TO AVIATION INTERESTS. && .GRB WATCHES/WARNINGS/ADVISORIES... HEAT ADVISORY FROM NOON TO 9 PM CDT MONDAY FOR WIZ020-021-030- 031-035>040-045-048>050-073-074. && $$ MPC/TE