Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 07/24/13


SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION...UPDATED
NWS LOS ANGELES/OXNARD CA
715 PM PDT TUE JUL 23 2013 UPDATED AVIATION SECTION .SYNOPSIS... A SLIGHT WARMING TREND IS EXPECTED THROUGH THE END OF THE WEEK AS HIGH PRESSURE BUILDS TO THE EAST THEN EXPANDS WEST. SLIGHTLY COOLER WEATHER WILL RETURN FOR SUNDAY AND EARLY NEXT WEEK AS A WEAK UPPER LOW MOVES OVER THE AREA...FOLLOWED BY ANOTHER WARMUP THROUGH MID WEEK. OTHER THAN SOME NIGHT THROUGH MORNING LOW CLOUDS AND FOG NEAR THE COAST...FAIR WEATHER IS EXPECTED FOR THE NEXT SEVEN DAYS. && .SHORT TERM (TODAY-FRI)...HAVE MADE MINOR CHANGES THROUGH THE PERIOD. GUIDANCE INITIALIZED A TROUGH UPSTREAM AND MOISTURE FIELD OVER THE AREA REASONABLY WELL AND WAS CONSISTENT WITH PREVIOUS RUNS. THE TROUGH UPSTREAM WILL PERSIST UPSTREAM WHILE A SUBTROPICAL LONG WAVE RIDGE BUILDS OVER THE AREA THROUGH FRIDAY AND WARMING TREND IS EXPECTED. INLAND TEMPERATURES WILL LIKELY WARM 3 TO 6 DEGREES ABOVE SEASONAL NORMAL BY FRIDAY WHILE MARINE LAYER PERSISTS AT THE COAST TEMPERATURES WILL REMAIN BELOW NORMAL. THE GOES SOUNDER AND RAP HAD INDICATED DECREASING STABILITY OVER VENTURA/LOS ANGELES MOUNTAINS AND DESERT AND ISOLATED CUMULUS FIELD HAD DEVELOPED EARLY THIS AFTERNOON. STABILITY IS EXPECTED TO INCREASE AS MID LEVELS WARM AND HEIGHTS RISE THROUGH THE EVENING. THE ISOLATED CUMULUS FIELD OVER THE MOUNTAINS WILL LIKELY DISSIPATE LATE THIS AFTERNOON. ISOLATED SHOWERS AND THUNDERSTORMS WERE DEVELOPING WELL EAST OF THE AREA EARLY THIS AFTERNOON AND WERE SHORT LIVED. THE ACTIVITY WILL REMAIN EAST OF THE AREA AS THE STORMS PROPAGATE GRADUALLY EAST. OTHERWISE MOISTURE FIELD INITIALIZED OVER MEXICO THIS MORNING WILL GRADUALLY PROPAGATE WEST THROUGH THE PERIOD. .LONG TERM (SAT-TUE)...GFS ANALOG GUIDANCE INDICATED LITTLE OR NO CHANCE OF PRECIPTITION OVER THE AREA SATURDAY. A TROUGH THAT WAS UPSTREAM OF THE AREA IN THE SHORT TERM IS EXPECTED TO MOVE ASHORE SATURDAY AND LIMIT THE WESTWARD PROPAGATION OF THE TROPICAL MOISTURE THAT WILL ARRIVE SOUTHEAST OF THE AREA FRIDAY NIGHT. A COOLING TREND IS EXPECTED SATURDAY THROUGH SUNDAY WITH TEMPERATURES 4 TO 8 DEGREES BELOW SEASONAL NORMAL BY SUNDAY. THE MID/UPPER LEVEL TROUGH OF LOW PRESSURE MAY MODIFY THE MARINE LAYER SUNDAY AND THE MARINE CLOUDS MAY BECOME SCATTERED MONDAY THROUGH TUESDAY. OTHERWISE A LONG WAVE SUBTROPICAL RIDGE EAST OF THE AREA WILL REBUILD WHILE SHIFTING WEST AND A WARMING TREND IS EXPECTED OVER THE AREA MONDAY THROUGH TUESDAY THOUGH TEMPERATURES ARE EXPECTED TO REMAIN A COUPLE DEGREES BELOW SEASONAL NORMAL. && .AVIATION...24/0215Z. LIFR TO IFR CONDITIONS WILL LIKELY SPREAD INTO COASTAL TERMINALS BETWEEN THROUGH 10Z TONIGHT...THEN PERSIST THROUGH 18Z AT THE LATEST. OTHERWISE...VFR CONDITIONS ARE EXPECTED. KLAX...VFR CONDITIONS WILL PERSIST THROUGH AT LEAST 04Z...THEN THERE IS A 70 PERCENT CHANCE OF LIFR TO IFR CONDITIONS AT KLAX BY 09Z. LIFR TO IFR CONDITIONS SHOULD LIFT ONE CATEGORY BETWEEN 15Z AND 16Z. VFR CONDITIONS SHOULD REDEVELOP BETWEEN 17Z AND 18Z. KBUR...VFR CONDITIONS ARE EXPECTED THROUGHOUT THE PERIOD. THERE IS A 20 PERCENT CHANCE OF MVFR CONDITIONS BETWEEN 10Z AND 16Z. && .LOX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ PUBLIC...30 AVIATION...HALL SYNOPSIS...SUKUP WWW.WEATHER.GOV/LOSANGELES
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1110 PM MDT SUN JUL 21 2013 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 304 PM MDT SUN JUL 21 2013 DRIER AIR MASS HAS SPREAD OVER THE NORTHERN AND WESTERN PORTIONS OF THE AREA THIS AFTERNOON...DROPPING DEW POINTS INTO THE 20S OVER THE CENTRAL MOUNTAINS AND ACROSS TELLER COUNTY. LOW LEVEL MOISTURE STILL LURKS ON THE PLAINS...WHERE DEWPOINTS IN THE 50S HAVE LED TO CAPES IN EXCESS OF 2K J/KG EAST OF I-25. VERY LITTLE IN THE WAY OF FORCING/UPWARD MOTION THIS AFTERNOON...WITH ONLY VERY SPARSE MOUNTAIN CONVECTION MAINLY SOUTH OF HIGHWAY 50. HAVE ALSO SEEN A COUPLE CELLS DEVELOP THEN DISSIPATE QUICKLY OVER EASTERN EL PASO COUNTY...WHERE MOISTURE GRADIENT IS FAIRLY TIGHT AND RESIDUAL BOUNDARY FROM LAST NIGHT`S CONVECTION REMAINS. LATEST HRRR HINTS AT TSRA DEVELOPING EAST OF I-25 THIS EVENING....AND WHILE FORCING IS WEAK...LARGE CAPES ARE HARD TO IGNORE...AND WILL THROW IN SOME LOW POPS FOR THE PLAINS EARLY THIS EVENING. STILL EXPECT ANY STORMS TO DISSIPATE QUICKLY AFTER SUNSET. ON MONDAY...AIR MASS CONTINUES TO DRY...AND EVEN THE MOUNTAINS WILL BE HARD PRESSED TO SEE MORE THAN SOME MODERATE CUMULUS BUILD-UP IN THE AFTERNOON. KEPT SOME VERY LOW POPS IN PLACE OVER THE HIGHER PEAKS...BUT EVEN THESE MAY BE OVERDONE. RISING HEIGHTS AND MID-LEVEL TEMPS SUGGEST A HOT DAY IS IN STORE...AS READINGS ON THE PLAINS REACH 100F...WITH 80/90S ELSEWHERE. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 304 PM MDT SUN JUL 21 2013 THE ENTIRE EXTENDED FORECAST PERIOD CAN BE SUMMED UP IN TWO SENTENCES. AN UPPER RIDGE OF HIGH PRESSURE WILL REMAIN LOCKED INTO PLACE ACROSS THE REGION. MINOR DISTURBANCES IN THE FLOW ALOFT ROTATING AROUND THE RIDGE WILL KICK OFF ENHANCED CONVECTION TOWARDS THE LATTER HALF OF THE WEEK. NOW FOR THE SPECIFICS... MONDAY NIGHT THROUGH TUESDAY...EC...GFS AND EVEN THE NAM MODEL ARE NOW INDICATING THAT IT SHOULD REMAIN FAIRLY DRY THROUGH MUCH OF TUE...WITH ISOLATED TO LOW END SCATTERED POPS OVER THE HIGHER TERRAIN. A COLD FRONT DROPS DOWN TO THE PALMER DVD ON TUE...BUT THE LATEST RUNS INDICATE IT DOES NOT DROP SOUTH UNTIL LATE TUE...SETTING THE STAGE FOR WED. LOOK FOR MAX TEMPS ACROSS THE E PLAINS TO BE AROUND 100 DEG F ON TUE...AND IN THE MID TO UPPER 80S FOR THE HIGH VALLEYS. WEDNESDAY THROUGH FRIDAY...THE COLD FRONT WILL DROP SOUTH ACROSS THE CWA LATE TUE...WITH WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY EXPECTED FOR A MAJORITY OF THE FORECAST AREA BOTH WED AND THU. MAX TEMPS ARE EXPECTED TO BE ABOUT 10 DEGREES COOLER WITH SCATTERED POPS ALL AREAS BORDERING ON LIKELY. WED AFTN THROUGH THU AFTN LOOKS LIKE IT WILL BE THE MOST PROBABLY TIME FRAME FOR FLASH FLOOD POTENTIAL ACROSS AREA BURN SCARS. BY FRIDAY THE UPPER RIDGE AXIS STARTS TO SHIFT SLIGHTLY TO THE EAST AS THE RIDGE AMPLIFIES...AND THOUGH THERE IS STILL A GOOD CHANCE FOR CONVECTION FOR ALL AREAS...IT WILL BE DUE TO A REINFORCED MONSOON PLUME AS OPPOSED TO FRONTAL/LLVL FORCING. TEMPS ON FRI WILL BE AS COOL OR PERHAPS EVEN A COUPLE OF DEGREES COOLER. SATURDAY AND SUNDAY...EXTENDED MODELS ARE POINTING TO ANOTHER STRONGER DISTURBANCE MOVING ACROSS THE DAKOTAS AND MIDWEST ON SAT...PUSHING ANOTHER COLD SURGE INTO EASTERN CO LATE SAT INTO SUN. WHEREAS SAT IS FORECAST TO HAVE DIURNAL CONVECTIVE ACTIVITY TIED MAINLY TO THE HIGHER TERRAIN...SUNDAY COULD BE ANOTHER ACTIVE DAY WITH WIDESPREAD CONVECTION AND SLIGHTLY COOLER TEMPS. MOORE && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1110 PM MDT SUN JUL 21 2013 UPPER HIGH EXPECTED TO AMPLIFY ACROSS THE GREAT BASIN DRIER WITHIN THE WEAK NORTHERLY FLOW ALOFT PUSHING MONSOONAL MOISTURE PLUME SOUTH AND WEST OF THE AREA THROUGH THE DAY TOMORROW. THIS WILL KEEP VFR CONDTIONS IN PLACE AT TAF SITES WITH ISOLATED MAINLY HIGH BASED CONVECTION EXPECTED TO STAY OVER AND NEAR THE HIGHER TERRAIN. && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...PETERSEN LONG TERM...MOORE AVIATION...MW
AREA FORECAST DISCUSSION
NWS TAUNTON MA
724 AM EDT MON JUL 22 2013 .SYNOPSIS... A STALLED FRONT SOUTH OF NEW ENGLAND WILL PUSH NORTH ACROSS THE REGION LATE TONIGHT INTO TUESDAY BRINGING NUMEROUS SHOWERS AND SCATTERED THUNDERSTORMS WITH LOCALLY HEAVY RAINFALL POSSIBLE. A COLD FRONT WILL SWEEP ACROSS NEW ENG WEDNESDAY FOLLOWED BY COOLER AND LESS HUMID WEATHER THURSDAY AND FRIDAY. WARMER AIR RETURNS FOR NEXT WEEKEND BEFORE A COLD FRONT NEXT SUN MAY BRING ADDITIONAL SCATTERED SHOWERS/THUNDERSTORMS. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 7 AM UPDATE... SURFACE FRONTAL BOUNDARY REMAIN SOUTH OF THE REGION WHILE VERTICAL WIND PROFILERS ARE EXHIBITING LIGHT SOUTHERLY FLOW ACROSS LONG ISLAND WITH A MORE EASTERLY COMPONENT OVER THE TAUNTON WEATHER FORECAST OFFICE. WHETHER THE QUASI-STATIONARY STORM OVER THE SOUTHERN WATERS IS A SIGN OF THINGS TO COME...THERE IS SURELY CONCERN OVER THE POTENTIAL FOR PERSISTENT HEAVY RAIN ALONG THE SURFACE FRONTAL BOUNDARY AS IT SLOWLY LIFTS NORTH TODAY. WAVERING CONFIDENCE WITH HOW THE TODAYS WEATHER IS GOING TO SPECIFICALLY PLAY OUT. FEEL A BLEND OF THE SREF/NAM/ECMWF IS A GOOD STARTING POINT. WRF-MODEL SOLUTIONS AND THE HRRR ARE VALUABLE APPROXIMATIONS OF POTENTIAL SCENARIOS WHEN EVALUATING SIMULATED RADAR REFLECTIVITY. TWO AREAS OF CONCERN: TRAINING OF PERSISTENT RAIN AND EMBEDDED HEAVIER SHOWERS / THUNDERSTORMS ALONG THE FRONTAL BOUNDARY...AND THE POTENTIAL FOR BOUNDARY LAYER DESTABILIZATION ACROSS THE INTERIOR. SO THERE COULD BE ISSUES ALONG THE SOUTH COAST ALONG WITH INTERIOR SHOWERS. ECHO THE PREVIOUS FORECASTERS THINKING...THERE IS ENOUGH MOISTURE IN THE COLUMN FOR MORE CLOUDS THAN SUNSHINE AND MODELS ARE GENERATING MARGINAL INSTABILITY TO SUPPORT SCATTERED SHOWERS AND THUNDERSTORMS AS WEAK SHORTWAVE ENERGY APPROACHES FROM THE GREAT LAKES. THUS THE BEST CHANCE FOR CONVECTION WILL BE ACROSS CENTRAL AND WESTERN AREAS FURTHER REMOVED FROM MORE STABLE MARITIME AIR. CAPES ARE FORECAST TO BE AOB 1000 J/KG WITH POOR MID LEVEL LAPSE RATES SO SEVERE WEATHER IS NOT ANTICIPATED...BUT A HEAVY RAIN THREAT WITH THE POTENTIAL FOR LOCALIZED FLOODING WILL EXIST. EASTERLY FLOW DEVELOPS WHICH WILL RESULT IN COOLER TEMPS WITH MAXES MOSTLY UPPER 70S TO LOWER 80S...BUT IT WILL BE HUMID WITH DEWPOINTS FORECAST TO INCREASE TO NEAR 70. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/... MID LEVEL TROF ACROSS THE GT LAKES FORECAST TO MOVE EAST TOWARD NEW ENGLAND LATE TONIGHT INTO TUE WITH MULTIPLE SHORTWAVES MOVING THROUGH THE FLOW. THE SFC BOUNDARY TO THE S WILL BEGIN TO MOVE BACK AS A WARM FRONT LATER TONIGHT BUT IT IS UNCERTAIN HOW FAR N THIS BOUNDARY WILL GET ON TUE. WE DISCOUNTED THE GFS WHICH APPEARS TOO AGGRESSIVE WITH PUSHING THE FRONT INTO N NEW ENG. WE USED A BLEND OF NAM/ECMWF WHICH BRINGS IT INTO SNE ALTHOUGH THE EXACT LOCATION IS UNCERTAIN. WE EXPECT INCREASING COVERAGE OF SHOWERS/TSTMS LATE TONIGHT INTO TUE AS THE SHORTWAVES MOVE INTO NEW ENG WITH RIGHT ENTRANCE REGION OF UPPER JET PROVIDING EXTRA DYNAMICAL SUPPORT. PWATS INCREASE TO GREATER THAN 2" SO PRIMARY THREAT WILL BE LOCALLY HEAVY RAINFALL. LOCATION OF THE SFC BOUNDARY WILL DETERMINE WHERE AXIS OF HEAVIEST RAINFALL SETS UP WHICH AT THIS TIME APPEARS TO BE NORTH AND WEST OF THE I95 CORRIDOR...BUT THIS COULD CHANGE. SEVERE THREAT IS LOW DUE TO ABUNDANT CLOUD COVER AND WEAK SHEAR. MAXES TUE WILL BE IN THE UPPER 70S TO LOWER 80S AND CONTINUED QUITE HUMID AS DEWPOINTS INCREASE INTO THE LOWER 70S. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... HEADLINES... * WET WEATHER DIMINISHING INTO WEDNESDAY * DRY AND SEASONABLE CONDITIONS PREVAIL FOR THE LATE WEEK * SEVERE WEATHER POSSIBLE FOR SATURDAY AND AGAIN SUNDAY? * DRY AND BELOW-SEASONABLE CONDITIONS HINTED FOR NEXT WEEK */OVERVIEW AND MODEL CONSENSUS... SUITE OF FORECAST GUIDANCE FINALLY COMING INTO BETTER AGREEMENT WHILE NO LONGER SUGGESTING ANOMALOUS DEEP NORTHERN STREAM TROUGHING ACROSS THE EASTERN CONUS. FEEL AN EQUAL BLEND OF DETERMINISTIC FORECAST GUIDANCE IS WELCOMED...BUT AM CAUTIOUS AS THIS IS ONLY THE FIRST INSTANCE OVER THE PAST WEEK IN WHERE THE GUIDANCE HAS BECOME WELL-ALIGNED. JUST YESTERDAY OUTCOMES WERE CONSIDERABLY DIFFERENT ACROSS THE NORTHEASTERN CONUS. AM WANTING TO SEE MODEL CONSISTENCY FOR THE NEXT COUPLE OF RUNS PRIOR TO JUMPING ON ANY ONE THOUGHT PROCESS...SO AGREE WITH WPC/HPC IN UTILIZING ENSEMBLE MEANS AS ELSEWHERE ACROSS THE CONUS...ESPECIALLY WITHIN THE SHORT-TERM... PACIFIC DISTURBANCES MOVING THROUGH THE BROADER LONGWAVE FLOW ARE STILL BEING HANDLED DIFFERENTLY BETWEEN FORECAST SOLUTIONS LENDING TO CONFLICTING SURFACE OUTCOMES. NOTHING IS CONCRETE. UPDATE: 22.0Z ECMWF HAS TRENDED A MORE ANOMALOUS NORTHERN STREAM TROUGHING SOLUTION. FEEL THIS IS A CONSEQUENCE OF POOR HANDLING OF PACIFIC DISTURBANCES AROUND THE DEEPER LOW OVER ONTARIO. WILL FOREGO THE SOLUTION WITH THIS FORECAST AND MAINTAIN WITH THE 22.0Z GFS AND 21.12Z ECMWF CONSISTENCY. */DAY-TO-DAY DETAILS... */TUESDAY NIGHT INTO WEDNESDAY... WEAK SURFACE LOW COUPLED TO THE RIGHT-REAR QUADRANT OF THE UPPER- LEVEL JET AND DEEP-LAYER ASCENT LIFT NORTHEASTWARD /22.0Z NAM IS SLOWEST WITH THIS OUTCOME/. WHILE A SURFACE TROUGH ATTENDANT TO THE LOW LINGERS ACROSS SOUTHERN NEW ENGLAND...THIS WILL BE WASHED OUT AS THE MAIN IMPULSE THROUGH THE BROAD TROUGH PATTERN PUSHES COOLER AND DRIER AIR BEHIND A WELL-DEFINED SURFACE COLD FRONT THROUGH THE NORTHEASTERN CONUS. THIS WILL PUSH THE DEEPER PWAT AXIS OFFSHORE LIMITING THE HEAVY RAIN THREAT. WILL DIMINISH CHANCE POPS NORTHWEST TO SOUTHEAST GRADUALLY THROUGH THE PERIOD. NO MENTION OF HEAVY RAIN WILL BE MADE TO THE FORECAST. LITTLE CONFIDENCE FOR THUNDERSTORMS WITH DRIER AIR BUILDING INTO THE REGION AND LIKELY BROADER SUBSIDENCE BEHIND THE AFOREMENTIONED MAIN IMPULSE THROUGH THE DAY WEDNESDAY. SOUTHWEST WINDS BACKING OUT OF THE NORTH-NORTHWEST AND DIMINISHING WITH FRONTAL PASSAGE. */WEDNESDAY NIGHT THROUGH FRIDAY NIGHT... AN AMAZING ABOUT FACE IN THE FORECAST GUIDANCE WHICH JUST LAST NIGHT WAS SUGGESTING CONTINUED RAIN CHANCES. WITH THIS FORECAST A SIMPLE RULE APPLIES: BETWEEN TWO REGIONS OF RISING AIR THERE NEEDS TO BE A BALANCE BETWEEN OF SINKING MOTIONS. WITH ENERGY ELONGATED ALONG AN OFFSHORE STALLED FRONTAL BOUNDARY AGAINST THE BROADER ATLANTIC RIDGE AND A STRONG IMPULSE ACROSS QUEBEC...THE NORTHEASTERN CONUS FINDS ITSELF IN A FAVORABLE REGION OF SINKING DRIER AIR. WITH BOTH THE 22.0Z GFS AND 21.12Z ECMWF NO LONGER EXHIBITING ANOMALOUS DEEP NORTHERN STREAM TROUGHING...RATHER WELL UNIFIED IN THE EVOLUTION OF AN OCCLUDED LOW PRESSURE CENTER OVER THE SOUTHERN HUDSON BAY REGION...WILL BLEND THE SOLUTIONS AND KEEP THE FORECAST PERIOD DRY. THE PREVAILING PERIOD OF BROAD HIGH PRESSURE WILL ALLOW FOR LIGHT WINDS ACROSS THE REGION. WILL LIKELY SEE SUCCESSIVE DAYS OF SEA-BREEZES ALONG THE SHORES THURSDAY AND FRIDAY. BROADER TROUGHING ACROSS THE REGION WILL KEEP TEMPERATURES SEASONABLE. SOME UNCERTAINTY ON FRIDAY...FALLING HEIGHTS WITH A WEAK TROUGH ACROSS THE REGION SUGGESTED. IF MID- TO UPPER-LIFT IS MATERIALIZES AND COLLOCATES WITH LOW-LEVEL CONVERGENCE ALONG SEA-BREEZES...IT IS PLAUSIBLE TO SEE SOME SHOWERS. BOTH THE GFS AND ECMWF SUGGEST POOR MID-LEVEL LAPSE RATES IN THE REGION OF THE LEFT-REAR QUAD OF THE UPPER-LEVEL JET...SO THIS LESSENS CONFIDENCE OF SHOWER AND T-STORM ACTIVITY. */SATURDAY INTO SUNDAY... MAIN IMPULSE AND DEEP-LOW PUSH OUT OF THE SOUTHERN HUDSON BAY REGION. ATTENDANT COLD FRONT SWEEPS THROUGH THE NORTHEASTERN CONUS DURING THE TIMEFRAME...THOUGH THE TIMING IS SOMEWHAT UNCERTAIN. NEVERTHELESS...CLIMATOLOGICALLY THE SYNOPTIC SETUP SUPPORTS THE POTENTIAL FOR SEVERE WEATHER ACROSS THE NORTHEASTERN CONUS. IT IS ENTIRELY PLAUSIBLE TO SEE SUCCESSIVE DAILY EPISODES...THE FIRST ACROSS THE NY/PA INTO WESTERN NEW ENGLAND...THE SECOND OVER NEW ENGLAND ITSELF. A DAY 6/7 FORECAST...THERE IS STILL A FAIR AMOUNT OF UNCERTAINTY. HAVE MORE CONFIDENCE WITH THE 21.12Z ECMWF OUTCOMES. WILL GO WITH CHANCE POPS FOR SHOWERS AND THUNDERSTORMS. WON/T SPECULATE AT THIS TIME ABOUT SPECIFIC SEVERE WEATHER OUTCOMES...NOR HEAVY RAIN IMPACTS...AWAITING LATER MODEL SOLUTIONS TO EVALUATE CONSISTENCY. */INTO NEXT WEEK... CONSISTENCY BETWEEN THE 21.18Z AND 22.0Z GFS COUPLED WITH THE 21.12Z ECMWF SUGGEST HIGH PRESSURE BUILDING SOUTHEASTWARD INTO SOUTHERN NEW ENGLAND AS THE DEEP LOW OVER CANADA LIFTS NORTHEAST THROUGH QUEBEC. COOL MID-LEVEL AIR WITH SURFACE NORTHWEST FLOW SUGGESTS CONDITIONS BELOW SEASONABLE LEVELS WHILE REMAINING DRY. && .AVIATION /11Z MONDAY THROUGH FRIDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. INCREASING AREAL COVERAGE OF -RA WITH EMBEDDED +RA/TSRA. WILL SEE LOWERING CIGS TOWARDS EVENING...DETERIORATING INTO THE OVERNIGHT. LIGHT AND VARIABLE WIND FLOW AS A FRONTAL BOUNDARY LIFTS THROUGH THE REGION. UNCERTAIN ON EXACT SPECIFICS AND SUBSEQUENT TRENDS... BUT CONFIDENT THAT CONDITIONS WILL DETERIORATE AS SHRA/TSRA BECOME WIDESPREAD INTO TUESDAY. KBOS TERMINAL...MODERATE CONFIDENCE IN TAF. LOWER CIGS COULD DEVELOP SOONER THAN FORECAST. KBDL TERMINAL...MODERATE CONFIDENCE IN TAF. LOWER CIGS COULD DEVELOP SOONER THAN FORECAST. OUTLOOK...TUESDAY NIGHT INTO FRIDAY NIGHT... TUESDAY NIGHT INTO WEDNESDAY...HIGH CONFIDENCE. SHRA AND POSSIBLE TSRA LINGERING. WILL SEE ANY MVFR/IFR CONDITIONS GRADUALLY LIFTING. COLD FRONT SWEEPING THROUGH THE TERMINALS. WILL SEE SOUTHWEST WINDS /POTENTIALLY GUSTY/ BACKING OUT OF THE NORTH- NORTHWEST AND WEAKENING. ANY COASTAL FOG SHOULD BE SCOURED OUT. WEDNESDAY NIGHT INTO FRIDAY NIGHT...MODERATE CONFIDENCE. VFR WITH HIGH PRESSURE IN CONTROL. SEA-BREEZES ALONG THE SHORES. PERHAPS A SLIGHT CHANCE FOR SHRA/TSRA ON FRIDAY...LOW CONFIDENCE. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. HIGH CONFIDENCE THROUGH TUESDAY. LIGHT PRES GRADIENT WILL KEEP WINDS BELOW SMALL CRAFT CRITERIA THROUGH THE PERIOD. SEAS WILL BE BELOW SCA AS WELL BUT COULD BUILD TO 5 FT OVER THE SOUTHERN WATERS BY LATE TUE. OUTLOOK...TUESDAY NIGHT INTO FRIDAY NIGHT... TUESDAY NIGHT INTO WEDNESDAY...HIGH CONFIDENCE. COLD FRONT TO SWEEP ACROSS THE WATERS WEDNESDAY ALONG AND AHEAD OF WHICH SOUTHWEST WINDS WILL GUST UP TO AROUND 20 KTS. SHRA/TSRA ALSO LINGERING WITH POSSIBLE COASTAL FOG IMPACTS. WILL SEE CONDITIONS IMPROVE LATE AS WINDS BACK OUT OF THE NORTH-NORTHWEST AND WEAKEN. DRIER AIR BUILDING INTO THE REGION SHOULD ALLOW ANY FOG CONDITIONS TO LIFT. SEAS TO BEGIN TO SUBSIDE WITH LESSER FLOW. WEDNESDAY NIGHT INTO FRIDAY NIGHT...MODERATE CONFIDENCE. HIGH PRESSURE BUILDING INTO THE WATERS. WINDS BECOMING LIGHT. WAVE HEIGHTS SHOULD DIMINISH EARLY IN THE PERIOD AND REMAIN BELOW 5 FEET THROUGHOUT THE FORECAST. SEA-BREEZES WILL DEVELOP DURING THE DAY ALONG THE IMMEDIATE SHORES. && .TIDES/COASTAL FLOODING... ASTRONOMICAL TIDES WILL BE ABNORMALLY HIGH DURING THE HIGH TIDE CYLCE NEAR MIDNIGHT TONIGHT. BOS TIDE IS 12.1 FT WHICH IS ABOUT AS HIGH AS IT EVER GETS. WITH LIGHT EASTERLY FLOW EXPECT ABOUT A 0.5 FT TIDAL DEPARTURE WHICH SHOULD BE ENOUGH TO PRODUCE SOME SPLASHOVER ALONG THE MOST VULNERABLE LOCATIONS ACROSS E COASTAL MA. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...NONE. && $$ SYNOPSIS...KJC/SIPPRELL NEAR TERM...KJC/SIPPRELL SHORT TERM...KJC LONG TERM...SIPPRELL AVIATION...KJC/SIPPRELL MARINE...KJC/SIPPRELL TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION...UPDATED MARINE
NWS JACKSONVILLE FL
943 PM EDT TUE JUL 23 2013 .UPDATE...MODERATE TO STRONG SHOWERS AND TSTMS ARE MOVING OUT OF SE GA THAT DEVELOPED ON OUTFLOW BOUNDARIES...BUT WEAKENING QCLS IS MOVING SE THROUGH SW GA AND THE CENTRAL FL. HAVE ADJUSTED POPS UPWARD AND MOVED FORWARD IN TIME FOR THE NRN AND WRN ZONES AS THE SYSTEM MOVES ESE ABOUT 25-30 MPH. FOR NOW HAVE CAPPED POPS NEAR 50-60% OVER EXTREME WRN ZONES WITH 20-40% ELSEWHERE BUT MAY NEED TO INCREASE FURTHER OVER THE NEXT COUPLE OF HRS DEPENDING ON RADAR IMAGERY AND HRRR GUIDANCE. BELIEVE MOST OF THE CONVECTION SHOULD BE WEAK WITH A GOOD PORTION OF THE CWA BEING WORKED OVER BY SCT CONVECTION EARLIER IN THE DAY. MUCAPE VALUES SHOULD BE DROPPING BELOW 1000 J/KG REST OF TONIGHT. GUSTY WINDS AND LOCALLY HEAVY RAINFALL ARE THE MAIN CONCERNS REST OF TONIGHT. ADJUSTED MIN TEMPS UP 1-2 DEGS DUE TO CLOUD COVER. && .AVIATION...MULTILAYERED CLOUDINESS EXPECTED OVERNIGHT WITH POSSIBILITY OF A FEW SHOWERS IN THE VICINITY OF THE TERMINALS MAINLY BTN 02Z-06Z AT SSI AND LATER IN THE NIGHT FOR REST OF AIRPORTS. SOME IFR CIGS CREPT INTO VQQ AREA RECENTLY BUT MAY BE SHORT-LIVED. DUE TO LOWER CONFIDENCE AND LOWER LEVELS OF IMPACT HAVE LEFT OUT CONVECTIVE OR ASSOCD LOWER CIGS UNTIL RESIDUAL CONVECTION COMES CLOSER TO TAFS. && .MARINE...SOUTHWEST TO WEST WINDS NEAR 15-20 KT EXPECTED TONIGHT WITH EXERCISE CAUTION HEADLINES. SEAS UP TO 3-5 FT OFFSHORE AND 2-3 NEARSHORE REST OF TONIGHT. RIDGE AXIS SETTLES INTO SOUTHERN FLORIDA LATER THIS WEEK. RIP CURRENTS: LOW RISK THROUGH WED DUE TO OFFSHORE FLOW THOUGH A WEAK ELY SWELL COMPONENT WILL CONTINUE. && .PRELIMINARY POINT TEMPS/POPS... AMG 73 91 73 93 / 40 40 40 50 SSI 76 90 77 88 / 30 30 30 40 JAX 73 90 74 90 / 30 60 40 40 SGJ 73 89 74 89 / 30 50 40 40 GNV 72 89 72 91 / 40 60 50 50 OCF 72 88 73 92 / 30 60 50 50 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...NONE. GA...NONE. AM...NONE. && $$ SHASHY/SHULER/WALKER
AREA FORECAST DISCUSSION
NWS JACKSONVILLE FL
931 PM EDT TUE JUL 23 2013 .UPDATE...MODERATE TO STRONG SHOWERS AND TSTMS ARE MOVING OUT OF SE GA THAT DEVELOPED ON OUTFLOW BOUNDARIES...BUT WEAKENING QCLS IS MOVING SE THROUGH SW GA AND THE CENTRAL FL. HAVE ADJUSTED POPS UPWARD AND MOVED FORWARD IN TIME FOR THE NRN AND WRN ZONES AS THE SYSTEM MOVES ESE ABOUT 25-30 MPH. FOR NOW HAVE CAPPED POPS NEAR 50-60% OVER EXTREME WRN ZONES WITH 20-40% ELSEWHERE BUT MAY NEED TO INCREASE FURTHER OVER THE NEXT COUPLE OF HRS DEPENDING ON RADAR IMAGERY AND HRRR GUIDANCE. BELIEVE MOST OF THE CONVECTION SHOULD BE WEAK WITH A GOOD PORTION OF THE CWA BEING WORKED OVER BY SCT CONVECTION EARLIER IN THE DAY. MUCAPE VALUES SHOULD BE DROPPING BELOW 1000 J/KG REST OF TONIGHT. GUSTY WINDS AND LOCALLY HEAVY RAINFALL ARE THE MAIN CONCERNS REST OF TONIGHT. ADJUSTED MIN TEMPS UP 1-2 DEGS DUE TO CLOUD COVER. && .AVIATION...MULTILAYRED CLOUDINESS EXPECTED OVERNIGHT WITH POSSIBILITY OF A FEW SHOWERS IN THE VICINITY OF THE TERMINALS MAINLY BTN 02Z-06Z AT SSI AND LATER IN THE NIGHT FOR REST OF AIRPORTS. SOME IFR CIGS CREPT INTO VQQ AREA RECENTLY BUT MAY BE SHORT-LIVED. DUE TO LOWER CONFIDENCE AND LOWER LEVELS OF IMPACT HAVE LEFT OUT CONVECTIVE OR ASSOCD LOWER CIGS UNTIL RESIDUAL CONVECTION COMES CLOSER TO TAFS. && .MARINE...SOUTHWEST TO WEST WINDS NEAR 15-20 KT EXPECTED TONIGHT OFFSHORE WITH EXERCISE CAUTION HEADLINE. SEAS AROUND 2-4 FT REST OF TONIGHT. RIDGE AXIS SETTLES INTO SOUTHERN FLORIDA LATER THIS WEEK. RIP CURRENTS: LOW RISK THROUGH WED DUE TO OFFSHORE FLOW THOUGH A WEAK ELY SWELL COMPONENT WILL CONTINUE. && .PRELIMINARY POINT TEMPS/POPS... AMG 73 91 73 93 / 40 40 40 50 SSI 76 90 77 88 / 30 30 30 40 JAX 73 90 74 90 / 30 60 40 40 SGJ 73 89 74 89 / 30 50 40 40 GNV 72 89 72 91 / 40 60 50 50 OCF 72 88 73 92 / 30 60 50 50 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...NONE. GA...NONE. AM...NONE. && $$ SHASHY/SHULER/WALKER
AREA FORECAST DISCUSSION
NWS MIAMI FL
912 PM EDT TUE JUL 23 2013 .UPDATE... A FEW SHOWERS/TSTMS ARE LINGERING OVER AND NEAR THE WESTERN SUBURBS OF SE FLORIDA THIS EVENING AS THE LAST OF TODAY`S CONVECTION MOVES EAST. EXPECT THIS ACTIVITY TO EITHER DISSIPATE OR MOVE OFFSHORE BY MIDNIGHT AT THE LATEST, WITH MOSTLY CLEAR AND DRY CONDITIONS EXPECTED FOR THE OVERNIGHT HOURS. ZONES WILL BE UPDATED BEFORE 11 PM TO REFLECT THIS, UNLESS SHOWERS/TSTMS LINGER LONGER THAN EXPECTED. HYDROLOGY UPDATE...FLOOD WARNING FOR FISHEATING CREEK WILL BE REEVALUATED WITH NEW RFC GUIDANCE WITHIN THE HOUR TO DETERMINE IF THE WARNING NEEDS TO BE CONTINUED. CREEK LEVELS HAVE BEEN FALLING SLIGHTLY SINCE THIS MORNING AND WITH NOT MUCH RAIN IN THE AREA TODAY, THE CREEK MAY NOT REACH THE FORECAST FLOOD STAGE OF 7 FEET. MOLLEDA && .PREV DISCUSSION... /ISSUED 750 PM EDT TUE JUL 23 2013/ AVIATION... CONVECTION ACROSS INTERIOR SHOULD CONTINUE TO BE DRIVEN BY LINGERING OUTFLOW BOUNDARIES ACROSS INTERIOR PALM BEACH...BROWARD AND MIAMI-DADE COUNTIES FOR THE NEXT FEW HOURS BEFORE DISSIPATING. OTHERWISE...SOUTHEASTERLY FLOW SHOULD VEER MORE SOUTHWESTERLY OVERNIGHT AND REMAIN LIGHT. SOUTHWESTERLY FLOW SHOULD PREVAIL THROUGH THE DAY TOMORROW WHICH SHOULD FOCUS ANY CONVECTIVE DEVELOPMENT ALONG THE INTERIOR AND EAST COASTAL AREAS. PREV DISCUSSION... /ISSUED 215 PM EDT TUE JUL 23 2013/ SHORT TERM (TONIGHT-THURSDAY NIGHT)... A STRONG SUBTROPICAL DEEP LAYER RIDGE CURRENTLY LOCATED ACROSS SOUTH FLORIDA AND THIS SUPPRESSING THE CONVECTION. THE 12Z MFL SOUNDING SHOWED THE LOWEST LAYERS OF THE ATMOSPHERE HAD DESTABILIZED SUBSTANTIALLY FROM 24 HOURS AGO SO CU DEVELOPED EARLIER WHICH HAS LEAD TO EARLIER SHOWER DEVELOPMENT TOO ALONG WITH A FEW THUNDERSTORMS. A SEA BREEZE LINE OF CONVECTION DEVELOPED RIGHT ALONG THE COAST OF SOUTHERN BROWARD AND IT APPEARS THAT SOME ADDITIONAL CONVERGENCE SET UP OTHER THAN JUST THE SEA BREEZE. LOOKING AT VISIBLE SATELLITE IMAGES REVEALS A CONVERGENT BOUNDARY ASSOCIATED WITH AN OUTFLOW/LAND BREEZE OFF THE EAST COAST WITH THIS BAND EXTENDING WELL OUT INTO THE ATLANTIC. OUTSIDE OF THIS, THERE IS ALSO A MID LEVEL TROUGH THAT IS DEEPENING OVER THE EASTERN STATES WITH FORECAST SOUNDINGS INDICATING THE RIDGE WOULD BEGIN TO SHIFT SOUTH THROUGH THIS AFTERNOON AND THIS APPEARS TO BE OCCURRING WITH LOW TOPPED CONVECTION ALREADY DRIFTING TO THE EAST. HOWEVER, AS THE DAY PROGRESSES AND DIURNAL HEATING CAN DESTABILIZE A DEEPER PORTION OF THE ATMOSPHERE THE STEERING FLOW IS STILL VERY WEAK SO STORM MOTION IS STILL EXPECTED TO BE SLOW AND POSSIBLY ERRATIC ALTHOUGH THERE COULD BE A DRIFT TOWARDS THE EAST. SOME OF THE SHORT RANGE HIGH RESOLUTION MODELS SUCH AS THE HRRR ARE SHOWING MORE ROBUST CONVECTION FORMING OVER THE INTERIOR AROUND 17-18Z (ALTHOUGH THIS NOT OCCURRING AS OF 1815Z) AND THEN SLOWLY MOVING TOWARDS THE EAST BUT THEN AS THE HEATING CYCLE IS CUT OFF WITH A LOWER SUN ANGLE, THE CONVECTION NEVER MAKES IT QUITE TO THE EAST COAST AND THIS APPEARS REASONABLE GIVEN THE ABOVE REASONING. THE RIDGE WILL CONTINUE TO SHIFT SOUTH TONIGHT AND BE OVER THE FLORIDA STRAITS INCLUDING THE KEYS AS THE TROUGH CONTINUES TO DEEPEN. THIS WILL ALLOW FOR A DEEP WESTERLY FLOW TO BECOME ESTABLISHED ON WEDNESDAY AND THURSDAY WITH FORECASTING SOUNDINGS SHOWING A STORM MOTION OF AROUND 5-7 MPH ON WEDNESDAY AND NEAR 10 MPH ON THURSDAY. NONE OF THE GLOBAL MODELS HOWEVER INDICATE AN ABUNDANCE OF DEEP LAYER AVAILABLE MOISTURE NOR INSTABILITY SO WIDESPREAD CONVECTION AT THIS TIME IS NOT EXPECTED. THE NAM, GFS AND ECMWF ALL SHOW PWAT IN THIS TIME FRAME TO BE 1.5-1.7 INCHES WHICH IS CLOSE TO OR SLIGHTLY BELOW THE AVERAGE FOR MID TO LATE JULY. BUT THE SCATTERED STORMS THAT DO DEVELOP IN THIS PATTERN WILL FAVOR THE INTERIOR AND EAST COAST METRO AREAS. LONG TERM (FRIDAY-TUESDAY)... NOT MUCH CHANGE IS FORESEEN LOOKING TOWARDS THE END OF THE WEEK INTO SATURDAY AS THE MAIN MID LEVEL TROUGH WILL REMAIN IN PLACE ACROSS THE EASTERN STATES. THIS WILL MAINTAIN THE DEEP WESTERLY FLOW ACROSS SOUTH FLORIDA WITH A FORECAST PWAT REMAINING NEAR NORMAL VALUES. NONE OF THE MODELS SHOW ANY KIND OF MOISTURE INFLUX SO AT THIS TIME, BY LATE IN THE WEEKEND AND INTO EARLY NEXT WEEK SCATTERED THUNDERSTORMS ARE EXPECTED WITH THE PATTERN AGAIN REVERTING TO MOSTLY INTERIOR AWAY FROM BOTH COASTS. MARINE... LIGHT SOUTH TO SOUTHEAST WIND WILL VEER TO A SOUTH TO SOUTHWEST DIRECTION ON WEDNESDAY AND CONTINUE THROUGH FRIDAY WITH SEAS LESS THAN 4 FEET AS THE RIDGE SHIFTS SOUTH OF THE AREA. THE RIDGE WILL THEN MOVE BACK NORTH OVER THE WEEKEND WITH A RETURN TO A LIGHT SOUTHEAST WIND. FIRE WEATHER... NO PROBLEMS OR CONCERNS WITH AMPLE TROPICAL MOISTURE. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 75 90 75 91 / 20 40 20 40 FORT LAUDERDALE 77 90 77 91 / 20 40 20 30 MIAMI 77 90 76 91 / 20 30 20 30 NAPLES 76 88 74 89 / - 20 10 20 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ PUBLIC/MARINE...59/MOLLEDA AVIATION/RADAR...10/CD
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
911 PM EDT Tue Jul 23 2013 .NEAR TERM [Through Tonight]... The main focus for the remainder of tonight is the MCS moving through southeastern Alabama. Currently, there is a line of storms extending northeast from Panama City to Albany heading southeast. Although radar trends have been indicating a weakening of this line, there are still areas of severe damaging winds upwards of 60 mph indicated on radar. High-res model guidance including the HRRR and our local WRF indicate that this line should fall apart shortly after midnight as it progresses further east, which seems reasonable given current radar trends. Therefore for the remainder of tonight expect scattered thunderstorms with lows reaching the lower 70s. && .SHORT TERM [Wednesday Through Thursday Night]... The axis of the upper trough will be just to our east through the short term period with a few more upper level impulses poised to affect the local area. The current timing of the impulses would yield a fairly active day (50%) for convection for all zones Wednesday and our easternmost zones Thursday as models show a much drier airmass in the mid-levels filtering in from west to east. With the drier airmass and less cloud cover, max temps may reach the mid 90s most inland areas Thursday. Otherwise, temps will be near seasonal levels through the period. && .LONG TERM [Friday through Tuesday]... The overall upper level pattern will show a ridge over the western CONUS and troughing over the east. Friday, our CWA will continue to reside on the backside of the east coast trough and we should get a brief break between shortwaves. A fairly strong shortwave will translate out of the Southern Plains into the Lower Mississippi Valley and sharpen as well as reposition the trough axis just to our west over the weekend. The most active day for convection appears to on Sunday when the trough axis reaches its greatest amplitude along with a few impulses and deep layer moisture returning to the FA. Thereafter, the trough will slowly deamplify and may allow the ridge to build into the local region early next week. PoPs will be below seasonal levels (10-30%) Friday gradually returning to normal (40-50%) Sunday through Tuesday. Temperatures will be at or below seasonal levels. && .AVIATION [Through 00Z Thursday]... Expect thunderstorms and gusty winds moving across our terminals as a line of strong to severe thunderstorms traverses our CWA. The strongest storms have ended at DHN and ECP, but TLH, VLD, and ABY will likely see thunderstorms and gusty winds until about midnight. In the early morning hours will likely see MVFR/IFR CIGs and visibilities develop. DHN, ABY, and VLD have the potential to reach LIFR but confidence remains low at this time. Expect thunderstorms to develop beginning in the northwest and spreading southeast towards the end of the TAF period. && .MARINE... A line of thunderstorms will move across our coastal waters tonight and gusty winds may be possible with these storms as well as waterspouts. Beyond tonight, high pressure to the south and a trough of low pressure to the north, will allow light to moderate westerly flow to continue over the coastal waters through the end of the week. Outside of thunderstorms, winds are expected to remain below headline criteria. && .FIRE WEATHER... Red flag conditions are not expected for the next several days. && .HYDROLOGY... A few rivers still remain at or near flood stage. Isolated instances of flash flooding or low land flooding will remain a concern near any stronger rain cores, especially near urban areas. Scattered showers and storms are expected through much of this week. && .PRELIMINARY POINT TEMPS/POPS... Tallahassee 73 93 73 94 73 /100 50 30 30 20 Panama City 77 89 78 93 77 /100 50 30 30 20 Dothan 73 91 73 94 74 /100 50 30 20 10 Albany 74 93 73 94 73 /100 50 30 30 10 Valdosta 73 95 73 93 72 / 70 50 30 50 20 Cross City 73 91 74 92 74 / 60 50 30 50 30 Apalachicola 78 90 77 91 75 /100 50 30 30 30 && .TAE WATCHES/WARNINGS/ADVISORIES... FL...None. GA...None. AL...None. GM...None. && $$ NEAR TERM...Navarro/Moore SHORT TERM...Barry LONG TERM...Barry AVIATION...Navarro/Moore MARINE...Moore/DVD FIRE WEATHER...Lahr/Camp HYDROLOGY...DVD
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
908 PM EDT TUE JUL 23 2013 .UPDATE... OVERNIGHT INTO WED... EARLY PASSAGE OF SHOWERS/STORMS/OUTFLOW BOUNDARY ACROSS THE NORTH HALF OF THE AREA AND SUBSEQUENT DEBRIS CLOUDS CONFINED MAIN STORMS THIS AFTERNOON/EVENING TO FOCUS IN AREAS AROUND OKEECHOBEE. THIS ACTIVITY WAS JUST ABOUT OFFSHORE MARTIN COUNTY. ONCE THIS CLEARS THE COAST...FAIR WEATHER WILL OCCUR THE REST OF THE EVENING. OVERNIGHT INTO WED MORNING THERE IS SOME CONCERN THAT A SOUTHEAST MOVING OUTFLOW BOUNDARY FROM CURRENT CONVECTION OVER THE FLORIDA PANHANDLE COULD REACH OUR NORTHERN SECTIONS AND BE THE FOCUS FOR SOME SHOWERS THERE. THE RAP AND LOCAL WRF MODELS SHOW THE MAIN CONVECTION OVER THE NORTHEAST GULF OF MEXICO BUT WILL ADD A SMALL CHANCE FOR SHOWERS LATE TONIGHT. WITH THE BOUNDARY AND APPROACH OF A SHORTWAVE TROUGH ALOFT...EXPECT BAND OF SHOWERS/STORMS TO MARCH ACROSS THE NORTH HALF EARLY AGAIN WED...MAYBE EVEN EARLIER THAN TODAY. && .AVIATION...FEW STORMS PUSHING OFFSHORE SOUTH OF KFPR THEN VFR EXPECTED MOST OF THE NIGHT. WITH MUCH OF THE AREA REALLY NOT GETTING RAIN COOLED TODAY...AND AN APPROACHING OUTFLOW BOUNDARY FROM THE NORTHWEST...THERE COULD BE A FEW SHOWERS OCCURRING AFTER MIDNIGHT...ESPECIALLY NORTHWARD FROM KISM-KMCO-KTIX. THE LATEST MODELS SHOW BAND OF CONVECTION PUSHING ACROSS THE PENINSULA QUITE EARLY AGAIN ON WED...MAYBE EVEN EARLIER THAN TODAY. HENCE INCLUDED VCTS KISM-KMCO-KTIX STARTING 14-16Z. && .MARINE...TONIGHT-WED...WEST/SOUTHWEST FLOW CURRENTLY LOOKS TO BE NEAR 15 KNOTS IN THE NORTH AND 10 KNOTS OR LESS SOUTH. THE MODELS SHOW MOSTLY 10-15 KNOT SOUTHWEST FLOW OVERNIGHT AND WED. THE MAIN CONCERN FOR BOATERS THOUGH ON WED WILL BE THE TIMING OF SHOWERS AND STORMS WITH GUSTY WINDS. THE LATEST INDICATIONS ARE THAT A BAND SHOULD MOVE OFFSHORE FROM THE CAPE NORTHWARD QUITE EARLY AGAIN ON WED...ABOUT LATE MORNING TO MIDDAY. THIS BAND SHOULD MOVE OFFSHORE SOUTH OF THE CAPE TO SEBASTIAN INLET DURING THE EARLY AFTERNOON...AND IN THE LATE AFTERNOON SOUTH OF THERE TO JUPITER INLET. THIS SLIGHTLY EARLIER OCCURRENCE IS DUE TO A LITTLE MORE POTENT SHORTWAVE TROUGH THAT IS FORECAST TO MOVE ACROSS THE NORTHERN HALF OF THE PENINSULA. && .MLB WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. && $$ FORECASTS...LASCODY IMPACT WEATHER...WIMMER
AREA FORECAST DISCUSSION
NWS MIAMI FL
750 PM EDT TUE JUL 23 2013 .AVIATION... CONVECTION ACROSS INTERIOR SHOULD CONTINUE TO BE DRIVEN BY LINGERING OUTFLOW BOUNDARIES ACROSS INTERIOR PALM BEACH...BROWARD AND MIAMI-DADE COUNTIES FOR THE NEXT FEW HOURS BEFORE DISSIPATING. OTHERWISE...SOUTHEASTERLY FLOW SHOULD VEER MORE SOUTHWESTERLY OVERNIGHT AND REMAIN LIGHT. SOUTHWESTERLY FLOW SHOULD PREVAIL THROUGH THE DAY TOMORROW WHICH SHOULD FOCUS ANY CONVECTIVE DEVELOPMENT ALONG THE INTERIOR AND EAST COASTAL AREAS. && .PREV DISCUSSION... /ISSUED 215 PM EDT TUE JUL 23 2013/ SHORT TERM (TONIGHT-THURSDAY NIGHT)... A STRONG SUBTROPICAL DEEP LAYER RIDGE CURRENTLY LOCATED ACROSS SOUTH FLORIDA AND THIS SUPPRESSING THE CONVECTION. THE 12Z MFL SOUNDING SHOWED THE LOWEST LAYERS OF THE ATMOSPHERE HAD DESTABILIZED SUBSTANTIALLY FROM 24 HOURS AGO SO CU DEVELOPED EARLIER WHICH HAS LEAD TO EARLIER SHOWER DEVELOPMENT TOO ALONG WITH A FEW THUNDERSTORMS. A SEA BREEZE LINE OF CONVECTION DEVELOPED RIGHT ALONG THE COAST OF SOUTHERN BROWARD AND IT APPEARS THAT SOME ADDITIONAL CONVERGENCE SET UP OTHER THAN JUST THE SEA BREEZE. LOOKING AT VISIBLE SATELLITE IMAGES REVEALS A CONVERGENT BOUNDARY ASSOCIATED WITH AN OUTFLOW/LAND BREEZE OFF THE EAST COAST WITH THIS BAND EXTENDING WELL OUT INTO THE ATLANTIC. OUTSIDE OF THIS, THERE IS ALSO A MID LEVEL TROUGH THAT IS DEEPENING OVER THE EASTERN STATES WITH FORECAST SOUNDINGS INDICATING THE RIDGE WOULD BEGIN TO SHIFT SOUTH THROUGH THIS AFTERNOON AND THIS APPEARS TO BE OCCURRING WITH LOW TOPPED CONVECTION ALREADY DRIFTING TO THE EAST. HOWEVER, AS THE DAY PROGRESSES AND DIURNAL HEATING CAN DESTABILIZE A DEEPER PORTION OF THE ATMOSPHERE THE STEERING FLOW IS STILL VERY WEAK SO STORM MOTION IS STILL EXPECTED TO BE SLOW AND POSSIBLY ERRATIC ALTHOUGH THERE COULD BE A DRIFT TOWARDS THE EAST. SOME OF THE SHORT RANGE HIGH RESOLUTION MODELS SUCH AS THE HRRR ARE SHOWING MORE ROBUST CONVECTION FORMING OVER THE INTERIOR AROUND 17-18Z (ALTHOUGH THIS NOT OCCURRING AS OF 1815Z) AND THEN SLOWLY MOVING TOWARDS THE EAST BUT THEN AS THE HEATING CYCLE IS CUT OFF WITH A LOWER SUN ANGLE, THE CONVECTION NEVER MAKES IT QUITE TO THE EAST COAST AND THIS APPEARS REASONABLE GIVEN THE ABOVE REASONING. THE RIDGE WILL CONTINUE TO SHIFT SOUTH TONIGHT AND BE OVER THE FLORIDA STRAITS INCLUDING THE KEYS AS THE TROUGH CONTINUES TO DEEPEN. THIS WILL ALLOW FOR A DEEP WESTERLY FLOW TO BECOME ESTABLISHED ON WEDNESDAY AND THURSDAY WITH FORECASTING SOUNDINGS SHOWING A STORM MOTION OF AROUND 5-7 MPH ON WEDNESDAY AND NEAR 10 MPH ON THURSDAY. NONE OF THE GLOBAL MODELS HOWEVER INDICATE AN ABUNDANCE OF DEEP LAYER AVAILABLE MOISTURE NOR INSTABILITY SO WIDESPREAD CONVECTION AT THIS TIME IS NOT EXPECTED. THE NAM, GFS AND ECMWF ALL SHOW PWAT IN THIS TIME FRAME TO BE 1.5-1.7 INCHES WHICH IS CLOSE TO OR SLIGHTLY BELOW THE AVERAGE FOR MID TO LATE JULY. BUT THE SCATTERED STORMS THAT DO DEVELOP IN THIS PATTERN WILL FAVOR THE INTERIOR AND EAST COAST METRO AREAS. LONG TERM (FRIDAY-TUESDAY)... NOT MUCH CHANGE IS FORESEEN LOOKING TOWARDS THE END OF THE WEEK INTO SATURDAY AS THE MAIN MID LEVEL TROUGH WILL REMAIN IN PLACE ACROSS THE EASTERN STATES. THIS WILL MAINTAIN THE DEEP WESTERLY FLOW ACROSS SOUTH FLORIDA WITH A FORECAST PWAT REMAINING NEAR NORMAL VALUES. NONE OF THE MODELS SHOW ANY KIND OF MOISTURE INFLUX SO AT THIS TIME, BY LATE IN THE WEEKEND AND INTO EARLY NEXT WEEK SCATTERED THUNDERSTORMS ARE EXPECTED WITH THE PATTERN AGAIN REVERTING TO MOSTLY INTERIOR AWAY FROM BOTH COASTS. MARINE... LIGHT SOUTH TO SOUTHEAST WIND WILL VEER TO A SOUTH TO SOUTHWEST DIRECTION ON WEDNESDAY AND CONTINUE THROUGH FRIDAY WITH SEAS LESS THAN 4 FEET AS THE RIDGE SHIFTS SOUTH OF THE AREA. THE RIDGE WILL THEN MOVE BACK NORTH OVER THE WEEKEND WITH A RETURN TO A LIGHT SOUTHEAST WIND. FIRE WEATHER... NO PROBLEMS OR CONCERNS WITH AMPLE TROPICAL MOISTURE. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 75 90 75 91 / 20 40 20 40 FORT LAUDERDALE 77 90 77 91 / 20 40 20 30 MIAMI 77 90 76 91 / 20 30 20 30 NAPLES 76 88 74 89 / - 20 10 20 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ DISCUSSION/MARINE/FIRE...59/RM AVIATION/RADAR...10/CD
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
613 AM EDT Mon Jul 22 2013 ...UPDATED FOR AVIATION SECTION... .NEAR TERM [TODAY]... The large scale longwave pattern is highlighted by weak ridging over Wrn Conus and a upper level trough amplifying from Great Lakes into Lwr MS Valley. Several shortwaves were noted in water vapor imagery moving across base of trough including one over NW AL. At the surface, a ridge of high pressure extends from the Atlc WWD across the FL Peninsula and Cntrl Gulf of Mexico. A weak and dissipating trough was noted across the WRN forecast area. 24hr temp/dew point comparisons indicate little change in airmass last 24 hrs. Latest radar pix shows noticeably less convection developing over the Gulf waters than forecast. Still, HRRR and WRF show marine convection moving onshore aft 10z from Panhandle waters reaching FL/AL border by 14z. Still have updated 06z-12z and 12z-18z Grids to lower POPS especially over waters and coasts and will monitor in case another update is needed. During the rest of today, progressive WSW steering flow as unseasonably amplified upper trough digs SEWD into TN Valley and deepens increasing tropical moisture plume, aided by AL shortwave moving ESE provides additional lift. Surface ridge remains to our S locally yielding SW flow. PWATs across the region from JAX west to Dothan and beyond in excess of 2 inches this aftn. This will combine with seabreeze/mesoscale outflows clashes from leftover boundaries from surface trough for sct/numerous showers and thunderstorms with heavy rain and gusty winds later today. As reflected in CAM and other models, highest POPs over the NW zones closest to the upper energy. Will go with 40-80% SE-NW POP gradient. RAP13 soundings show uni-directional very moist profiles which favor good rain producers and given recent rains, aggravate chances of at least nuisance flooding again today. CAM QPF/flood tools shows Panhandle as best bet with 1-2 inches avg STP. Although Shear unimpressive, model aftn CAPE around 2400 J/KG across SE AL. Add presence of shortwave plus any boundary clashes this favors at least strong storms to isold severe storms with best bet SE AL/ adjacent GA/FL 21z-00z. This, along with max temps will be partly dependent on amount of morning cloudiness and where drier air sets making max temp forecast a little tricky. Inland Highs generally 88 to 90. && .SHORT TERM [Tonight through Wednesday]... The pattern will transition to more of a northwest flow aloft through the short term as the upper level trough axis moves east of the area. A series of shortwaves is expected to move through the base of the trough and aid in convective development over the forecast area (PoPs 40-60% during the day). The northwest flow aloft will also aid in advecting steeper than normal mid-level lapse rates into the area by Tuesday into Wednesday, which may increase the threat of isolated, pulse severe storms. These would be most likely over the northern and western portions of the area. The 22/00z GFS forecasts 700-500 mb lapse rates between 6-7 C/km, which is 1-1.5 C/km above climo for this time of year. && .LONG TERM [Wednesday Night through Sunday]... The upper flow across the CONUS will be dominated by an eastern trough and western ridge. Through most of the extended period, the upper trough axis is forecast to be just east of the CWA, with northwest flow aloft. While this flow is typically drier across the region, the presence of a nearly stationary trough across the northern half of the area will offset this to some extent. With this in mind, will generally keep the PoPs at or below 50 percent through the extended, especially for Thursday into the weekend. With the slightly lower rain chances than the past several days, expect high temperatures to creep back into the lower to mid 90s as well. && .MARINE... With a persistent trough to the north and high pressure to the south, winds over the marine area will be primarily out of the southwest to west-southwest this week between 10 and 15 knots. && .AVIATION...[Through 12Z Tuesday] Although locales except DHN and TLH remain VFR at 10z, HRRR show showers and thunderstorms developing at our western terminals spreading E/NE reaching the FL/AL border thru 14z. Therefore decided to include MVFR CIGS 12-14z at above sites. After morning showers and thunderstorms diminish, there will likely be a break, and then another round in the afternoon with conditions very similar to what we saw on Sun with MVFR CIGS/VSBYS and gusty winds in any heavy rain or strong storms. After 00z VFR conditions return but after 07z, MVFR CIGS and possibly VSBYS especially where any residual moister remains form earlier storms. Brief IFR CIGS and MVFR VSBYS also possible near sunrise. && .FIRE WEATHER... Red flag conditions are not expected for the next several days. && .HYDROLOGY... A few rivers still remain at or near flood stage, including the Aucilla and Econfina rivers. The Steinhatchee river is also out of its banks south of US 19 with minor flooding expected downstream of the gage for the next day or two. Scattered showers and storms are expected through much of this week, but should not be sufficient to produce widespread flooding. However, localized areas of heavy rain are likely and could cause some urban and small stream flooding on occasion. && .PRELIMINARY POINT TEMPS/POPS... Tallahassee 89 74 92 74 93 / 60 50 60 50 50 Panama City 86 76 88 76 88 / 60 50 60 40 50 Dothan 88 73 92 73 91 / 70 40 60 50 50 Albany 89 73 92 74 92 / 70 40 60 40 50 Valdosta 89 73 92 74 94 / 70 40 60 40 50 Cross City 89 73 88 73 90 / 50 40 60 40 50 Apalachicola 86 77 88 77 90 / 60 50 60 40 50 && .TAE WATCHES/WARNINGS/ADVISORIES... FL...High Risk for Rip Currents for FLZ108-112-114. GA...None. AL...None. GM...None. && $$ Near Term/Aviation/Fire Wx...Block Short Term/Marine/Hydrology...DVD Long Term...Camp
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
356 AM EDT Mon Jul 22 2013 .NEAR TERM [Through Today]... The large scale longwave pattern is highlighted by weak ridging over Wrn Conus and a broad upper level trough across much of the Cntrl and Ern U.S. Several shortwaves were noted in water vapor imagery moving across base of trough including one over NW AL. At the surface, a ridge of high pressure extends from the Atlc WWD across the FL Peninsula and Cntrl Gulf of Mexico. A weak and dissipating trough was noted across the WRN forecast area. 24hr temp/dew point comparisons indicate little change in airmass last 24 hrs. Latest radar pix shows less convection than forecast developing over the Gulf waters. Still, HRRR and WRF show marine convection moving onshore after 10z from Panhandle waters reaching FL/AL border by 14z. Have updated 06z-12z Grids to lower POPS and will monitor in case another update is needed. During the rest of today, progressive WSW steering flow as unseasonably amplified upper trough digs SEWD into TN Valley and deepens increasing tropical moisture plume, aided by AL shortwave moving ESE provides additional lift. Surface ridge remains to our S locally yielding SW flow. PWATs across the region from JAX west to Dothan and beyond in excess of 2 inches this aftn. This will combine with seabreeze/mesoscale outflows clashes from leftover boundaries from surface trough for sct/numerous showers and thunderstorms later today. As reflected in CAM and other models, highest POPs over the NW zones closest to the upper energy. Will go with 40-80% SE-NW POP gradient. RAP13 soundings show uni- directional very moist profiles which favor good rain producers and given recent rains, aggravate chances of at least nuisance flooding again today. CAM QPF/flood tools shows Panhandle as best bet with 1-2 inches avg STP. Although Shear unimpressive, model aftn CAPE around 2400 J/KG across SE AL. Add presence of shortwave plus any boundary clashes this favors at least strong storms to isold severe storms with best bet SE AL/ adjacent GA/FL 21z-00z. This, along with max temps will be partly dependent on amount of morning cloudiness and where drier air sets making max temp forecast a little tricky. Inland Highs generally 88 to 90. && .SHORT TERM [Tonight through Wednesday]... The pattern will transition to more of a northwest flow aloft through the short term as the upper level trough axis moves east of the area. A series of shortwaves is expected to move through the base of the trough and aid in convective development over the forecast area (PoPs 40-60% during the day). The northwest flow aloft will also aid in advecting steeper than normal mid-level lapse rates into the area by Tuesday into Wednesday, which may increase the threat of isolated, pulse severe storms. These would be most likely over the northern and western portions of the area. The 22/00z GFS forecasts 700-500 mb lapse rates between 6-7 C/km, which is 1-1.5 C/km above climo for this time of year. && .LONG TERM [Wednesday Night through Sunday]... The upper flow across the CONUS will be dominated by an eastern trough and western ridge. Through most of the extended period, the upper trough axis is forecast to be just east of the CWA, with northwest flow aloft. While this flow is typically drier across the region, the presence of a nearly stationary trough across the northern half of the area will offset this to some extent. With this in mind, will generally keep the PoPs at or below 50 percent through the extended, especially for Thursday into the weekend. With the slightly lower rain chances than the past several days, expect high temperatures to creep back into the lower to mid 90s as well. && .AVIATION... [Through 06z Tuesday] Although locales remain VFR at 07z, HRRR show showers and thunderstorms developing at our western terminals aft 09z and spreading E/NE reaching the FL/AL border thru 14z. Therefore decided to include MVFR CIGS/VSBYS 09Z-14z except possibly at ECP with brief IFR/LIFR CIGs possible until around sunrise. After morning showers and thunderstorms diminish, there will likely be a break, and then another round in the afternoon with conditions very similar to what we saw on Sun with MVFR CIGS/VSBYS and gusty winds in any heavy rain or strong storms. && .MARINE... With a persistent trough to the north and high pressure to the south, winds over the marine area will be primarily out of the southwest to west-southwest this week between 10 and 15 knots. && .FIRE WEATHER... Red flag conditions are not expected for the next several days. && .HYDROLOGY... A few rivers still remain at or near flood stage, including the Aucilla and Econfina rivers. The Steinhatchee river is also out of its banks south of US 19 with minor flooding expected downstream of the gage for the next day or two. Scattered showers and storms are expected through much of this week, but should not be sufficient to produce widespread flooding. However, localized areas of heavy rain are likely and could cause some urban and small stream flooding on occasion. && .PRELIMINARY POINT TEMPS/POPS... Tallahassee 89 74 92 74 93 / 60 50 60 50 50 Panama City 86 76 88 76 88 / 60 50 60 40 50 Dothan 88 73 92 73 91 / 70 40 60 50 50 Albany 89 73 92 74 92 / 70 40 60 40 50 Valdosta 89 73 92 74 94 / 70 40 60 40 50 Cross City 89 73 88 73 90 / 50 40 60 40 50 Apalachicola 86 77 88 77 90 / 60 50 60 40 50 && .TAE WATCHES/WARNINGS/ADVISORIES... FL...High Risk for Rip Currents for FLZ108-112-114. GA...None. AL...None. GM...None. && $$ Near Term/Aviation/Fire Wx...Block Short Term/Marine/Hydrology...DVD Long Term...Camp
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
713 AM EDT MON JUL 22 2013 .SYNOPSIS... A TROUGH OF LOW PRESSURE AT THE SURFACE AND ALOFT WILL PREVAIL ALONG THE EAST COAST THROUGH MID WEEK. A WEAKENING COLD FRONT WILL APPROACH FROM THE NORTHWEST LATE WEDNESDAY THROUGH THURSDAY... STALLING NEAR THE AREA INTO THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... MADE A FEW CHANGES WITH THE EARLY MORNING UPDATE. 1. LOWERED POPS IN THE CHARLESTON TRI COUNTY AREA TO 40 PERCENT AND INCREASED POPS TO 70 PERCENT OVER PORTIONS OF LONG...MCINTOSH AND LIBERTY COUNTIES PER LATEST RUNS OF HIGH RESOLUTION MODELS. BOTH THE RAP AND H3R NOW FOCUS MOST OF THE CONVECTION SOUTH OF I-16 THIS AFTERNOON...ESPECIALLY NEAR THE ALTAMAHA RIVER. 2. ADJUSTED SKY COVER PER GOING SATELLITE TRENDS. IT NOW APPEARS A GOOD PORTION OF THE AREA WILL INITIALIZE WITH MOSTLY SUNNY SKIES THIS MORNING...ESPECIALLY IN THE BEAUFORT-SAVANNAH-LUDOWICI CORRIDOR. 3. RAISED HIGH TEMPERATURES BY 1-2 DEGREES FOR MOST AREAS SINCE A GOOD BIT OF SUN WILL OCCUR THIS MORNING AND TEMPERATURES ARE STARTING OUT A TAD HIGHER THAN EXPECTED EARLIER THIS MORNING. SUBTLE CHANGES ARE ONGOING IN THE ATMOSPHERE THIS MORNING WHICH WILL HAVE SOME IMPACTS ON THE EVENTUAL CONVECTIVE PATTERN TODAY. THE REGION WILL REMAIN IN THE FAMILIAR UPPER AIR CONFIGURATION FEATURING DEEP LAYERED HIGH PRESSURE CENTERED WELL OFFSHORE AND A TROUGH OF LOW PRESSURE LINGERING ACROSS THE SOUTHERN MISSISSIPPI VALLEY. THE UPPER TROUGH IS FORECAST TO PROPAGATE SLOWLY EAST WITH A LOBE OF VORTICITY EJECTING EAST ACROSS THE MIDLANDS AND UPSTATE DURING PEAK HEATING. THIS FEATURE COUPLED WITH HIGH PWATS AND DAYTIME HEATING WILL YIELD A DECENT AMOUNT OF SHOWERS/TSTMS ACROSS THE MIDLANDS AND POSSIBLY THE CSRA...ESPECIALLY THIS AFTERNOON. FARTHER SOUTH...MODELS SHOW A POCKET OF RELATIVELY LOWER MID- LEVEL THETA AIR MOVING ACROSS MUCH OF SOUTHEAST SOUTH CAROLINA AND SOUTHEAST GEORGIA THIS AFTERNOON. MORNING WATER VAPOR IMAGERY AND GOES SOUNDINGS ACROSS ALABAMA CONFIRM THIS POCKET OF DRY AIR EXISTS SO HAVE NO REASON TO BOUT ITS EXISTENCE. THIS LOWER THETA POCKET WILL LIKELY LIMIT THE COVERAGE OF SHOWER/TSTMS A BIT TODAY...ESPECIALLY WHEN COMPARED TO PREVIOUS DAYS. IN FACT...SOME OF THE GLOBAL MODELS SHOW VERY LITTLE IN THE WAY OF TSTM ACTIVITY FIRING TODAY. THE HIGHER RESOLUTION MODELS ARE LIKELY MORE REALISTIC DEPICTING CONVECTIVE CLUSTERS PROPAGATING IN FROM THE SOUTHWEST LATER THIS AFTERNOON AND AFFECTING SOUTHEAST GEORGIA OR MOVING IN FROM THE EASTERN MIDLANDS BY THIS EVENING AND IMPACTING SOUTHERN SOUTH CAROLINA. PWATS ARE FORECAST TO LOWER BELOW 2 INCHES LATER TODAY...BUT LOCALIZED FLOODING WILL REMAIN A CONCERN. OPTED TO STAY ON THE LOWER SIDE OF THE GUIDANCE ENVELOP FOR HIGH TEMPERATURES AS EXTENSIVE CLOUD COVER AND SOME CONVECTION WILL LIKELY LIMIT TEMPERATURES SOMEWHAT. HIGHS WILL RANGE FROM THE UPPER 80S INLAND TO THE MID 80S AT THE COAST. IF CLOUDS THIN MORE THAN EXPECTED...HIGHS COULD SOAR INTO THE LOWER 90S AS SUGGESTED BY SOME ENSEMBLE MEMBERS. && .SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/... TONIGHT...CONVECTION WILL GRADUALLY DISSIPATE THIS EVENING WITH DRY CONDITIONS PREVAILING OVERNIGHT. IT WILL REMAIN MOSTLY CLOUDY WITH LOTS OF DEBRIS CLOUDINESS IN PLACE. LOWS WILL RANGE FROM THE LOWER 70S INLAND TO THE MID-UPPER 70S AT THE COAST. TUESDAY AND WEDNESDAY...AN UPPER LEVEL TROUGH WILL AMPLIFY ALONG THE EAST COAST INTO THE MID WEEK PERIOD...WITH VARIOUS SHORTWAVES SHIFTING INTO THE REGION WITHIN WEST/NORTHWEST MID AND UPPER LEVEL FLOW. A WEAKENING COLD FRONT WILL ALSO BE APPROACHING FROM THE NORTHWEST AND SLIPPING TOWARD THE FORECAST AREA BY LATE WEDNESDAY...EMBEDDED WITHIN THE AXIS OF A SURFACE TROUGH DRIFTING TOWARD THE COASTLINE. CONVECTIVE COVERAGE...ALONG WITH THE POTENTIAL FOR HEAVY RAIN AND/OR SEVERE WEATHER...APPEARS HIGHLY DEPENDENT ON THE TIMING AND STRENGTH OF THE SERIES OF SHORTWAVES IMPACTING THE SOUTHEAST STATES THROUGH THE PERIOD. NUMERICAL MODEL SOLUTIONS SHOW NOTABLE VARIABILITY IN THEIR DEPICTION OF THIS ENERGY ALOFT...INCLUDING AREAS OF NEGATIVE VORTICITY ADVECTION THAT COULD LIMIT COVERAGE AT TIMES. DUE TO THIS UNCERTAINTY...HAVE LEANED TOWARD MORE CONSERVATIVE POPS TUESDAY AND WEDNESDAY. WILL CONTINUE TO HIGHLIGHT THE AFTERNOON AND EARLY EVENING PERIODS FOR BEST COVERAGE OVER LAND...WITH POPS GENERALLY PEAKING IN THE 30 TO 40 PERCENT RANGE. SHOWERS/THUNDERSTORMS SHOULD DIMINISH ACROSS LAND AREAS OVERNIGHT...WHILE THE MARINE ZONES EXPERIENCE AN INCREASE IN ACTIVITY THROUGH THE EARLY MORNING HOURS. PRECIPITABLE WATER WILL FALL BELOW 2 INCHES AND RANGE WITHIN MORE SEASONAL VALUES FOR LATE JULY. HEAVY RAIN POTENTIAL WILL BE REDUCED SLIGHTLY AS A RESULT...YET THE SUBSEQUENTLY DRIER MID LEVEL AIR AND INCREASE IN LAPSE RATES SUGGEST A HIGHER POTENTIAL FOR THE STRONGEST THUNDERSTORMS TO PRODUCE DOWNBURST WINDS. ALTHOUGH ORGANIZED SEVERE WEATHER IS STILL NOT EXPECTED AT THIS TIME...THERE IS A SMALL RISK FOR ISOLATED STORMS ENHANCED BY MESOSCALE BOUNDARY INTERACTIONS TO INTENSIFY TO SEVERE THRESHOLDS...WITH THE MAIN HAZARD BEING DAMAGING WIND GUSTS. THURSDAY...THE WEAKENING COLD FRONT WILL CONTINUE TO SLIP SOUTHEAST INTO THE FORECAST AREA...AS A DECENT WAVE OF LOW PRESSURE DEVELOPS ALONG THE BOUNDARY AND DRIFTS ACROSS THE SOUTHEAST COAST. THE AXIS OF THE STRONGEST IN THE SERIES OF SHORTWAVES WILL BE JUST UPSTREAM BY SUNSET...PROVIDING ADDITIONAL FORCING FOR ASCENT ACROSS THE REGION. DEEP MOISTURE WILL SURGE IN RESPONSE TO BOTH THE UPPER LEVEL ENERGY AND LOW LEVEL CONVERGENCE ALONG THE LINGERING FRONT. THE BEST CONVECTIVE COVERAGE OF THE SHORT TERM PERIOD COULD OCCUR THURSDAY AFTERNOON AS A RESULT. HEAVY RAIN COULD AGAIN BECOME A CONCERN CONSIDERING RISING PRECIPITABLE WATER VALUES. EXPECT LITTLE DAY TO DAY CHANGE IN TEMPERATURES THROUGH MID TO LATE WEEK. HAVE INDICATED HIGHS REACHING THE LOWER 90S EACH AFTERNOON AWAY FROM THE LOCALLY COOLER COASTLINE. LOW TEMPERATURES WILL GENERALLY FALL INTO THE LOW TO MID 70S INLAND. && .LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/... THE MAIN SHORTWAVE TROUGH WILL SHIFT INTO THE ATLANTIC LATE THURSDAY INTO FRIDAY...WITH A LESS AMPLIFIED UPPER LEVEL PATTERN PREVAILING THROUGH AT LEAST SATURDAY. THE LINGERING COLD FRONT WILL STALL AND EVENTUALLY DISSIPATE OVER THE SOUTHEAST STATES...WHILE UPPER RIDGING BRIEFLY ATTEMPTS TO BUILD BACK INTO THE REGION FROM THE SOUTH. WILL INDICATE MORE SEASONAL PRECIPITATION COVERAGE FRIDAY AND SATURDAY...WITH ISOLATED TO SCATTERED SHOWER/THUNDERSTORM ACTIVITY FOCUSED ALONG AND INLAND OF THE SEABREEZE EACH AFTERNOON/EARLY EVENING. THERE IS RATHER SIGNIFICANT DISAGREEMENT BETWEEN MEDIUM RANGE MODELS REGARDING THE STRENGTH OF ANOTHER UPPER TROUGH RAPIDLY MOVING INTO THE REGION SUNDAY AND MONDAY. PREFER TO MAINTAIN SOMEWHAT GENERIC RAIN CHANCES PEAKING IN THE 30 PERCENT RANGE EARLY NEXT WEEK UNTIL BETTER MODEL CONSISTENCY IS EVIDENT. HIGH TEMPERATURES WILL REACH THE LOWER 90S AWAY FROM THE COASTLINE EACH AFTERNOON. && .AVIATION /11Z MONDAY THROUGH FRIDAY/... KCHS...THE EASTERN EDGE OF A LOW CLOUD BANK HAS BRUSHED TERMINAL. SATELLITE DATA AND RAP SOUNDINGS SUGGEST HIGH END IFR/LOW END MVFR CIGS WILL LINGER THROUGH ABOUT 14Z THEN RETURN TO VFR. BEST TSTM CHANCES LOOK TO REMAIN WELL SOUTH OF KCHS TODAY...ALTHOUGH AN ISOLATED TSTM COULD STILL OCCUR. WILL KEEP ALL MENTION OF TSRA OUT OF THE KCHS TAF FOR NOW. KSAV...LOW CLOUDS LOOK TO REMAIN WEST OF THE TERMINAL THIS MORNING. HIGH RESOLUTION MODEL GUIDANCE SUGGEST TSTMS WILL MOVE IN FROM THE SOUTHWEST LATER THIS AFTERNOON AND POSSIBLY AFFECT THE TERMINAL. TIMING/COVERAGE IS STILL A BIT UNCERTAIN THIS FAR OUT. WILL CARRY A TEMPO GROUP FROM 20-23Z FOR 4SM -TSRA BR BKN040CB TO COVER FOR NOW. FURTHER REFINEMENTS WILL BE NEEDED AS THE DAY PROGRESSES. SHOWERS/TSTMS SHOULD QUICKLY DISSIPATE THIS EVENING THUS ENDING THE RISK FOR TSTM IMPACTS. EXTENDED AVIATION OUTLOOK...LITTLE CHANGE IN THE PATTERN THROUGH THURSDAY...WITH MAINLY DIURNAL CONVECTION AND THE CHANCE FOR LATE NIGHT/EARLY MORNING STRATUS. THIS WILL RESULT IN PERIODIC FLIGHT RESTRICTIONS THROUGH THE PERIOD. && .MARINE... TODAY AND TONIGHT...SOMEWHAT ELEVATED WINDS WILL REMAIN IN PLACE TODAY WITH SPEEDS GENERALLY 15-20 KT...EXCEPT CLOSER TO 15 KT IN THE CHARLESTON HARBOR. SEAS WILL RANGE FROM 2-4 FT NEARSHORE WATERS AND 4-5 FT OFFSHORE WATERS. ATTM IT APPEARS BOTH WINDS AND SEAS WILL REMAIN BELOW SMALL CRAFT ADVISORY CRITERIA. SIMILAR CONDITIONS ARE EXPECTED TONIGHT. TUESDAY AND WEDNESDAY...THE COASTAL WATERS WILL REMAIN BETWEEN THE SUB-TROPICAL ATLANTIC RIDGE TO THE SOUTH/SOUTHEAST...WHILE A PERSISTENT TROUGH OF LOW PRESSURE LINGERS INLAND. THE PRESSURE GRADIENT WILL BE UNSEASONABLY ENHANCED AS A RESULT...SUPPORTING WIND SPEEDS ABOVE NORMAL FOR LATE JULY. EXPECT WINDS TO PEAK AT 15 TO 20 KT THROUGH THE PERIOD...WITH OCCASIONAL GUSTS UP TO 25 KT. SMALL CRAFT ADVISORIES DO NOT APPEAR NECESSARY AT THIS TIME DUE TO THE INFREQUENCY OF HIGHER GUSTS. DIRECTIONS WILL BE MAINLY SOUTHWEST...VEERING A LITTLE AT NIGHT AND BACKING SOME DURING THE DAY WITHIN SEABREEZE CIRCULATIONS. SEAS WILL BE HELD UNDER 5 FT. MARINERS ARE ADVISED THAT ISOLATED SHOWERS AND THUNDERSTORMS COULD BECOME STRONG...WITH FREQUENT LIGHTNING AND HEAVY RAIN. ISOLATED STORMS COULD ALSO PRODUCE WIND GUSTS IN EXCESS OF 35 KT...AND SPECIAL MARINE WARNINGS MAY BECOME NECESSARY. CHECK NATIONAL WEATHER SERVICE FORECASTS AND NOAA WEATHER RADIO ALL HAZARDS BEFORE AND DURING ANY NAVIGATION INTO THE COASTAL WATERS. THURSDAY AND FRIDAY...THE PRESSURE GRADIENT WILL WEAKEN CONSIDERABLY LATE IN THE WEEK...AS THE INLAND TROUGH DRIFTS TOWARD THE COAST AND THE COLD FRONT STALLS INLAND. LIGHT WINDS COULD ACTUALLY BECOME VARIABLE AT TIMES...GENERALLY CAPPED NO HIGHER THAN 10 KT. OUTSIDE OF ANY CONVECTION...WINDS AND SEAS WILL BE WELL BELOW ANY SMALL CRAFT CONDITIONS. && .TIDES/COASTAL FLOODING... THE PERIGEAN SPRING TIDES WILL PERSIST TODAY SO ONLY SMALL POSITIVE TIDAL DEPARTURES MAY PRODUCE MINOR COASTAL FLOODING. SHOULD ANY SHALLOW SALT WATER COASTAL FLOODING OCCUR THE MOST LIKELY AREAS ARE CHARLESTON AND COASTAL COLLETON COUNTIES DURING THE EVENING HIGH TIDES THROUGH WEDNESDAY. IT IS IN THESE AREAS WHERE THE SMALLEST TIDAL DEPARTURES ARE REQUIRED FOR THE ISSUANCE OF AN ADVISORY. WE HAVE MAINTAINED MENTION OF THIS POTENTIAL IN THE HAZARDOUS WEATHER OUTLOOK. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...NONE. && $$ ST/WMS
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
625 AM EDT MON JUL 22 2013 .SYNOPSIS... A TROUGH OF LOW PRESSURE AT THE SURFACE AND ALOFT WILL PREVAIL ALONG THE EAST COAST THROUGH MID WEEK. A WEAKENING COLD FRONT WILL APPROACH FROM THE NORTHWEST LATE WEDNESDAY THROUGH THURSDAY... STALLING NEAR THE AREA INTO THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... MADE A FEW CHANGES WITH THE EARLY MORNING UPDATE. 1. LOWERED POPS IN THE CHARLESTON TRI COUNTY AREA TO 40 PERCENT AND INCREASED POPS TO 70 PERCENT OVER PORTIONS OF LONG...MCINTOSH AND LIBERTY COUNTIES PER LATEST RUNS OF HIGH RESOLUTION MODELS. BOTH THE RAP AND H3R NOW FOCUS MOST OF THE CONVECTION SOUTH OF I-16 THIS AFTERNOON...ESPECIALLY NEAR THE ALTAMAHA RIVER. 2. ADJUSTED SKY COVER PER GOING SATELLITE TRENDS. IT NOW APPEARS A GOOD PORTION OF THE AREA WILL INITIALIZE WITH MOSTLY SUNNY SKIES THIS MORNING...ESPECIALLY IN THE BEAUFORT-SAVANNAH-LUDOWICI CORRIDOR. 3. RAISED HIGH TEMPERATURES BY 1-2 DEGREES FOR MOST AREAS SINCE A GOOD BIT OF SUN WILL OCCUR THIS MORNING AND TEMPERATURES ARE STARTING OUT A TAD HIGHER THAN EXPECTED EARLIER THIS MORNING. SUBTLE CHANGES ARE ONGOING IN THE ATMOSPHERE THIS MORNING WHICH WILL HAVE SOME IMPACTS ON THE EVENTUAL CONVECTIVE PATTERN TODAY. THE REGION WILL REMAIN IN THE FAMILIAR UPPER AIR CONFIGURATION FEATURING DEEP LAYERED HIGH PRESSURE CENTERED WELL OFFSHORE AND A TROUGH OF LOW PRESSURE LINGERING ACROSS THE SOUTHERN MISSISSIPPI VALLEY. THE UPPER TROUGH IS FORECAST TO PROPAGATE SLOWLY EAST WITH A LOBE OF VORTICITY EJECTING EAST ACROSS THE MIDLANDS AND UPSTATE DURING PEAK HEATING. THIS FEATURE COUPLED WITH HIGH PWATS AND DAYTIME HEATING WILL YIELD A DECENT AMOUNT OF SHOWERS/TSTMS ACROSS THE MIDLANDS AND POSSIBLY THE CSRA...ESPECIALLY THIS AFTERNOON. FARTHER SOUTH...MODELS SHOW A POCKET OF RELATIVELY LOWER MID- LEVEL THETA AIR MOVING ACROSS MUCH OF SOUTHEAST SOUTH CAROLINA AND SOUTHEAST GEORGIA THIS AFTERNOON. MORNING WATER VAPOR IMAGERY AND GOES SOUNDINGS ACROSS ALABAMA CONFIRM THIS POCKET OF DRY AIR EXISTS SO HAVE NO REASON TO BOUT ITS EXISTENCE. THIS LOWER THETA POCKET WILL LIKELY LIMIT THE COVERAGE OF SHOWER/TSTMS A BIT TODAY...ESPECIALLY WHEN COMPARED TO PREVIOUS DAYS. IN FACT...SOME OF THE GLOBAL MODELS SHOW VERY LITTLE IN THE WAY OF TSTM ACTIVITY FIRING TODAY. THE HIGHER RESOLUTION MODELS ARE LIKELY MORE REALISTIC DEPICTING CONVECTIVE CLUSTERS PROPAGATING IN FROM THE SOUTHWEST LATER THIS AFTERNOON AND AFFECTING SOUTHEAST GEORGIA OR MOVING IN FROM THE EASTERN MIDLANDS BY THIS EVENING AND IMPACTING SOUTHERN SOUTH CAROLINA. PWATS ARE FORECAST TO LOWER BELOW 2 INCHES LATER TODAY...BUT LOCALIZED FLOODING WILL REMAIN A CONCERN. OPTED TO STAY ON THE LOWER SIDE OF THE GUIDANCE ENVELOP FOR HIGH TEMPERATURES AS EXTENSIVE CLOUD COVER AND SOME CONVECTION WILL LIKELY LIMIT TEMPERATURES SOMEWHAT. HIGHS WILL RANGE FROM THE UPPER 80S INLAND TO THE MID 80S AT THE COAST. IF CLOUDS THIN MORE THAN EXPECTED...HIGHS COULD SOAR INTO THE LOWER 90S AS SUGGESTED BY SOME ENSEMBLE MEMBERS. && .SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/... TONIGHT...CONVECTION WILL GRADUALLY DISSIPATE THIS EVENING WITH DRY CONDITIONS PREVAILING OVERNIGHT. IT WILL REMAIN MOSTLY CLOUDY WITH LOTS OF DEBRIS CLOUDINESS IN PLACE. LOWS WILL RANGE FROM THE LOWER 70S INLAND TO THE MID-UPPER 70S AT THE COAST. TUESDAY AND WEDNESDAY...AN UPPER LEVEL TROUGH WILL AMPLIFY ALONG THE EAST COAST INTO THE MID WEEK PERIOD...WITH VARIOUS SHORTWAVES SHIFTING INTO THE REGION WITHIN WEST/NORTHWEST MID AND UPPER LEVEL FLOW. A WEAKENING COLD FRONT WILL ALSO BE APPROACHING FROM THE NORTHWEST AND SLIPPING TOWARD THE FORECAST AREA BY LATE WEDNESDAY...EMBEDDED WITHIN THE AXIS OF A SURFACE TROUGH DRIFTING TOWARD THE COASTLINE. CONVECTIVE COVERAGE...ALONG WITH THE POTENTIAL FOR HEAVY RAIN AND/OR SEVERE WEATHER...APPEARS HIGHLY DEPENDENT ON THE TIMING AND STRENGTH OF THE SERIES OF SHORTWAVES IMPACTING THE SOUTHEAST STATES THROUGH THE PERIOD. NUMERICAL MODEL SOLUTIONS SHOW NOTABLE VARIABILITY IN THEIR DEPICTION OF THIS ENERGY ALOFT...INCLUDING AREAS OF NEGATIVE VORTICITY ADVECTION THAT COULD LIMIT COVERAGE AT TIMES. DUE TO THIS UNCERTAINTY...HAVE LEANED TOWARD MORE CONSERVATIVE POPS TUESDAY AND WEDNESDAY. WILL CONTINUE TO HIGHLIGHT THE AFTERNOON AND EARLY EVENING PERIODS FOR BEST COVERAGE OVER LAND...WITH POPS GENERALLY PEAKING IN THE 30 TO 40 PERCENT RANGE. SHOWERS/THUNDERSTORMS SHOULD DIMINISH ACROSS LAND AREAS OVERNIGHT...WHILE THE MARINE ZONES EXPERIENCE AN INCREASE IN ACTIVITY THROUGH THE EARLY MORNING HOURS. PRECIPITABLE WATER WILL FALL BELOW 2 INCHES AND RANGE WITHIN MORE SEASONAL VALUES FOR LATE JULY. HEAVY RAIN POTENTIAL WILL BE REDUCED SLIGHTLY AS A RESULT...YET THE SUBSEQUENTLY DRIER MID LEVEL AIR AND INCREASE IN LAPSE RATES SUGGEST A HIGHER POTENTIAL FOR THE STRONGEST THUNDERSTORMS TO PRODUCE DOWNBURST WINDS. ALTHOUGH ORGANIZED SEVERE WEATHER IS STILL NOT EXPECTED AT THIS TIME...THERE IS A SMALL RISK FOR ISOLATED STORMS ENHANCED BY MESOSCALE BOUNDARY INTERACTIONS TO INTENSIFY TO SEVERE THRESHOLDS...WITH THE MAIN HAZARD BEING DAMAGING WIND GUSTS. THURSDAY...THE WEAKENING COLD FRONT WILL CONTINUE TO SLIP SOUTHEAST INTO THE FORECAST AREA...AS A DECENT WAVE OF LOW PRESSURE DEVELOPS ALONG THE BOUNDARY AND DRIFTS ACROSS THE SOUTHEAST COAST. THE AXIS OF THE STRONGEST IN THE SERIES OF SHORTWAVES WILL BE JUST UPSTREAM BY SUNSET...PROVIDING ADDITIONAL FORCING FOR ASCENT ACROSS THE REGION. DEEP MOISTURE WILL SURGE IN RESPONSE TO BOTH THE UPPER LEVEL ENERGY AND LOW LEVEL CONVERGENCE ALONG THE LINGERING FRONT. THE BEST CONVECTIVE COVERAGE OF THE SHORT TERM PERIOD COULD OCCUR THURSDAY AFTERNOON AS A RESULT. HEAVY RAIN COULD AGAIN BECOME A CONCERN CONSIDERING RISING PRECIPITABLE WATER VALUES. EXPECT LITTLE DAY TO DAY CHANGE IN TEMPERATURES THROUGH MID TO LATE WEEK. HAVE INDICATED HIGHS REACHING THE LOWER 90S EACH AFTERNOON AWAY FROM THE LOCALLY COOLER COASTLINE. LOW TEMPERATURES WILL GENERALLY FALL INTO THE LOW TO MID 70S INLAND. && .LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/... THE MAIN SHORTWAVE TROUGH WILL SHIFT INTO THE ATLANTIC LATE THURSDAY INTO FRIDAY...WITH A LESS AMPLIFIED UPPER LEVEL PATTERN PREVAILING THROUGH AT LEAST SATURDAY. THE LINGERING COLD FRONT WILL STALL AND EVENTUALLY DISSIPATE OVER THE SOUTHEAST STATES...WHILE UPPER RIDGING BRIEFLY ATTEMPTS TO BUILD BACK INTO THE REGION FROM THE SOUTH. WILL INDICATE MORE SEASONAL PRECIPITATION COVERAGE FRIDAY AND SATURDAY...WITH ISOLATED TO SCATTERED SHOWER/THUNDERSTORM ACTIVITY FOCUSED ALONG AND INLAND OF THE SEABREEZE EACH AFTERNOON/EARLY EVENING. THERE IS RATHER SIGNIFICANT DISAGREEMENT BETWEEN MEDIUM RANGE MODELS REGARDING THE STRENGTH OF ANOTHER UPPER TROUGH RAPIDLY MOVING INTO THE REGION SUNDAY AND MONDAY. PREFER TO MAINTAIN SOMEWHAT GENERIC RAIN CHANCES PEAKING IN THE 30 PERCENT RANGE EARLY NEXT WEEK UNTIL BETTER MODEL CONSISTENCY IS EVIDENT. HIGH TEMPERATURES WILL REACH THE LOWER 90S AWAY FROM THE COASTLINE EACH AFTERNOON. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... TO BE ISSUED. EXTENDED AVIATION OUTLOOK...LITTLE CHANGE IN THE PATTERN THROUGH THURSDAY...WITH MAINLY DIURNAL CONVECTION AND THE CHANCE FOR LATE NIGHT/EARLY MORNING STRATUS. THIS WILL RESULT IN PERIODIC FLIGHT RESTRICTIONS THROUGH THE PERIOD. && .MARINE... TODAY AND TONIGHT...SOMEWHAT ELEVATED WINDS WILL REMAIN IN PLACE TODAY WITH SPEEDS GENERALLY 15-20 KT...EXCEPT CLOSER TO 15 KT IN THE CHARLESTON HARBOR. SEAS WILL RANGE FROM 2-4 FT NEARSHORE WATERS AND 4-5 FT OFFSHORE WATERS. ATTM IT APPEARS BOTH WINDS AND SEAS WILL REMAIN BELOW SMALL CRAFT ADVISORY CRITERIA. SIMILAR CONDITIONS ARE EXPECTED TONIGHT. TUESDAY AND WEDNESDAY...THE COASTAL WATERS WILL REMAIN BETWEEN THE SUB-TROPICAL ATLANTIC RIDGE TO THE SOUTH/SOUTHEAST...WHILE A PERSISTENT TROUGH OF LOW PRESSURE LINGERS INLAND. THE PRESSURE GRADIENT WILL BE UNSEASONABLY ENHANCED AS A RESULT...SUPPORTING WIND SPEEDS ABOVE NORMAL FOR LATE JULY. EXPECT WINDS TO PEAK AT 15 TO 20 KT THROUGH THE PERIOD...WITH OCCASIONAL GUSTS UP TO 25 KT. SMALL CRAFT ADVISORIES DO NOT APPEAR NECESSARY AT THIS TIME DUE TO THE INFREQUENCY OF HIGHER GUSTS. DIRECTIONS WILL BE MAINLY SOUTHWEST...VEERING A LITTLE AT NIGHT AND BACKING SOME DURING THE DAY WITHIN SEABREEZE CIRCULATIONS. SEAS WILL BE HELD UNDER 5 FT. MARINERS ARE ADVISED THAT ISOLATED SHOWERS AND THUNDERSTORMS COULD BECOME STRONG...WITH FREQUENT LIGHTNING AND HEAVY RAIN. ISOLATED STORMS COULD ALSO PRODUCE WIND GUSTS IN EXCESS OF 35 KT...AND SPECIAL MARINE WARNINGS MAY BECOME NECESSARY. CHECK NATIONAL WEATHER SERVICE FORECASTS AND NOAA WEATHER RADIO ALL HAZARDS BEFORE AND DURING ANY NAVIGATION INTO THE COASTAL WATERS. THURSDAY AND FRIDAY...THE PRESSURE GRADIENT WILL WEAKEN CONSIDERABLY LATE IN THE WEEK...AS THE INLAND TROUGH DRIFTS TOWARD THE COAST AND THE COLD FRONT STALLS INLAND. LIGHT WINDS COULD ACTUALLY BECOME VARIABLE AT TIMES...GENERALLY CAPPED NO HIGHER THAN 10 KT. OUTSIDE OF ANY CONVECTION...WINDS AND SEAS WILL BE WELL BELOW ANY SMALL CRAFT CONDITIONS. && .TIDES/COASTAL FLOODING... THE PERIGEAN SPRING TIDES WILL PERSIST TODAY SO ONLY SMALL POSITIVE TIDAL DEPARTURES MAY PRODUCE MINOR COASTAL FLOODING. SHOULD ANY SHALLOW SALT WATER COASTAL FLOODING OCCUR THE MOST LIKELY AREAS ARE CHARLESTON AND COASTAL COLLETON COUNTIES DURING THE EVENING HIGH TIDES THROUGH WEDNESDAY. IT IS IN THESE AREAS WHERE THE SMALLEST TIDAL DEPARTURES ARE REQUIRED FOR THE ISSUANCE OF AN ADVISORY. WE HAVE MAINTAINED MENTION OF THIS POTENTIAL IN THE HAZARDOUS WEATHER OUTLOOK. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...NONE. && $$ ST/WMS
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1150 PM CDT SUN JUL 21 2013 .DISCUSSION... ISSUED 850 PM CDT SUN JUL 21 2013 UPDATED THE FORECAST TONIGHT TO INCREASE CHANCES OF SHOWERS ALONG WITH A FEW THUNDERSTORMS. ALSO NUDGED UP LOW TEMPERATURES A DEGREE OR TWO TO AROUND 70F...DUE TO MOIST DEWPOINTS CURRENTLY IN THE LOW TO MID 70S. A FEW POCKETS OF LOCALLY HEAVY RAINS OF 1.5 TO 3 INCHES ALSO TO OCCUR TONIGHT ESPECIALLY FROM I-72 SOUTH...AS JACKSONVILLE HAS EXPERIENCED SINCE 5 PM. THE HRRR MODEL HAS BEEN HANDLING THIS WEATHER SYSTEM THE BEST SO FAR SO LEANED ON THIS MODEL FOR TONIGHT`S FORECAST. SHOWERS AND A FEW THUNDERSTORMS TO SPREAD INTO EASTCENTRAL IL NEXT NEW HOURS... THEN DIMINISH FROM WEST TO EAST LATE THIS EVENING AND OVERNIGHT. A SHORT WAVE MOVING INTO CENTRAL IL THIS EVENING AND EXITING SE OF AREA MONDAY MORNING WILL KEEP LIKELY CHANCES OF SHOWERS AND FEW THUNDERSTORMS PAST SUNDOWN TONIGHT AND LIKELY CHANCES CONTINUE OVER EASTERN IL OVERNIGHT...WHILE DIMINISHING TO SLIGHT CHANCE IN THE WEST. A QUASI STATIIONARY FRONTAL BOUNDARY OVER NE PARTS OF IA/IL AND INTO CENTRAL INDIANA WILL GRADUALLY WEAKEN THROUGH MONDAY...WITH CENTRAL/SE IL STAYING ON THE SOUTH SIDE (MILD/MOIST SIDE) OF THE BOUNDARY. TEMPS CURRENTLY IN THE 70S TO ONLY SLIP TOWARD 70F FOR LOWS OVERNIGHT WHICH JACKSONVILLE IS CURRENTLY DOWN TO WITH HEAVY RAINS PAST FEW HOURS FROM THUNDERSTORMS. EXPECT LIGHT SSE TO VARIABLE WINDS TONIGHT WITH SOME FOG POSSIBLE OVERNIGHT INTO MID MORNING MONDAY WITH VSBYS DOWN TO 1-3 MILES. 07 && .AVIATION... ISSUED 1150 PM CDT SUN JUL 21 2013 IFR TO MVFR VSBYS AND CEILINGS POSSIBLE WITH SHOWERS AND A FEW THUNDERSTORMS WITH LOCALLY HEAVY RAINS THE NEXT FEW HOURS AT DEC AND CMI WHILE A FEW LIGHT SHOWERS COULD BRING MVFR CONDITIONS TIL 08Z ALONG I-55 AT BMI AND SPI. CONVECTION TIED TO A SHORT WAVE THAT IT OVER CENTRAL IL AND TO EXIT SOUTHEAST OF AREA BY DAWN. HAVE 1-3 MILES WITH FOG DEVELOPING DURING OVERNIGHT UNTIL 14-15Z MONDAY. CLEARING SKIES WORKING EASTWARD FROM MO INTO WEST CENTRAL IL AROUND QUINCY LATE THIS EVENING. IF CLEARING SKIES TO GET INTO WESTERN TAF SITES OF PIA AND SPI AFTER 08Z WHERE FOG COULD BECOME MORE WIDESPREAD WITH PATCHY DENSE FOG EVEN POSSIBLE...THOUGH DID NOT CARRY VSBYS THAT LOW DUE TO UNCERTAINTY OF CLEARING ESPECIALLY OVER EASTERN TAF SITES. ANY LINGERING LOW CLOUDS AND FOG SHOULD LIFT AFTER 14-15Z MONDAY MORNING WITH BROKEN MVFR CEILINGS LINGERING LONGEST AT CMI POSSIBLY INTO MIDDAY. FAIR WEATHER EXPECTED MONDAY AFTERNOON/EVENING WITH COLD FRONT OVER THE NORTHERN PLAINS NOT IMPACTING CENTRAL IL TAF SITES UNTIL LATER MONDAY NIGHT INTO TUE. LIGHT AND VARIABLE WINDS OVERNIGHT TO BECOME SW 4-7 KTS AFTER 15Z/MON AND LIGHT SSW BY SUNSET MON EVENING. 07 && .PREV DISCUSSION... ISSUED 239 PM CDT SUN JUL 21 2013 MAIN CONCERNS THIS PACKAGE WILL CONTINUE TO BE PCPN CHANCES FOR THE SHORT TERM AND THEN PCPN CHANCES AGAIN AT THE END OF THE WEEK AND INTO THE WEEKEND...IN THE LONG TERM PERIOD. MODELS SHOW GOOD AGREEMENT WITH KEEPING THE MID LEVEL NORTHWEST FLOW IN PLACE...WITH A RIDGE BUILDING OUT OVER THE ROCKIE MOUNTAIN REGION...ALL THROUGH MID WEEK. THE NORTHWEST FLOW WILL ALSO CONTINUE INTO THE EXTENDED PERIOD AND MODELS LOOK OK HERE TOO UNTIL LATE IN THE WEEK AND THE WEEKEND. ECMWF APPEARS TO BE STRONGER WITH A MID LEVEL SYSTEM COMING DOWN INTO THE AREA DURING THE END OF THE PERIOD. SHORT TERM...TONIGHT THROUGH WEDNESDAY FRONTAL SYSTEM OVER THE AREA THIS AFTERNOON WILL GRADUALLY WASHOUT TONIGHT THROUGH TOMORROW AS A STRONGER WEATHER SYSTEM DEVELOPS OUT IN THE PLAINS. SHOWERS AND THUNDERSTORMS WILL REMAIN LIKELY ACROSS THE ENTIRE CWA THIS EVENING AND THEN IN THE EAST AFTER MIDNIGHT...WITH CHANCES BACK TO THE WEST. LIGHT SHOWERS ARE ONGOING BUT REMNANTS OF AN MCS IN IOWA HAVE CONTINUED TO GET STRONGER IN SOUTH CENTRAL IOWA AND WILL MOVE EAST-SOUTHEAST INTO THE CWA THIS EVENING AND THROUGH TONIGHT. BELIEVE THIS LINE/COMPLEX OF STORMS WILL FOLLOW THE STATIONARY BOUNDARY OVER THE AREA AS IT MOVES EAST-SOUTHEAST. VARIOUS SHORT TERM MODELS FORECAST THIS AREA OF STORMS EAST AND SOUTHEAST INTO CENTRAL ILLINOIS THIS EVENING...THEREFORE CONFIDENCE IS HIGH ENOUGH FOR LIKELY POPS. NO SEVERE IS EXPECTED WITH THESE STORMS...BUT LOCALLY HEAVY RAINFALL AND DEADLY LIGHTNING WILL BE LIKELY. PCPN WILL DIMINISH TOMORROW...BUT WITH LOTS OF LOW LEVEL MOISTURE AND A STATIONARY BOUNDARY IN THE AREA...CANT RULE OUT A CHANCE OF THUNDERSTORMS SOMEWHERE TOMORROW. PCPN CHANCES WILL CONTINUE AND INCREASE INTO TOMORROW NIGHT AND TUESDAY AS ANOTHER...STRONGER FRONT PUSHES INTO AND THROUGH THE AREA. FORECAST FOR THIS FRONT APPEAR TO BE THAT IT WILL PUSH SHOULD OF THE STATE LATE TUE NIGHT AND THEN BRING DRIER AND LESS HUMID AIR INTO THE REGION FOR WEDNESDAY. APPEARS TEMPS WILL BE QUITE WARM ONE MORE DAY TOMORROW. THEN ADDITIONAL CLOUD COVER AND PCPN WILL CAUSE TEMPS TO BE SLIGHTLY COOLER FOR TUESDAY. MUCH COOLER TEMPS ARE THEN EXPECTED AFTER THE FRONT MOVES THROUGH THE AREA FOR WEDNESDAY. LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY DRY WEATHER WILL CONTINUE THROUGH THUR NIGHT AS NORTHWEST FLOW WILL CONTINUE ACROSS THE AREA. A STRONGER SYSTEM/SHORT WAVE TROUGH WILL THEN DEVELOP AND MOVE TOWARD THE AREA FOR LATE IN THE WEEK. ECMWF IS STRONGER AND LOOKS MORE CONSISTENT FROM PREVIOUS RUNS WITH THIS NEXT SYSTEM...THAN THE GFS. LEANING TOWARD THE ECMWF MODEL GIVES A FORECAST OF PCPN CHANCES FOR FRIDAY THROUGH SATURDAY NIGHT...SOMEWHERE IN THE CWA...THEN DRY WEATHER POSSIBLE SUNDAY. STILL LOTS OF UNCERTAINTY WITH THIS PERIOD OF THE FORECAST SO WOULD NOT BE SURPRISED TO SEE CHANGES TO IT OVER THE NEXT SEVERAL DAYS. TEMPS SHOULD BE COOLER THAN LAST WEEK GIVEN THE NORTHWEST FLOW AND WENT COOLER THAN GUIDANCE FOR SAT AND SUNDAY. AUTEN && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
614 PM CDT TUE JUL 23 2013 ...UPDATED AVIATION DISCUSSION... .SYNOPSIS... ISSUED AT 925 AM CDT TUE JUL 23 2013 THE 23.12Z 250 HPA RAOB MAP SHOWED WESTERLY TO NORTHWESTERLY FLOW STRETCHING FROM OREGON TO THE MIDWEST. MAGNITUDES WERE 50-75 KT. @ 500 HPA, AN ELONGATED 592/593 DM ANTICYCLONE EXTENDED FROM NORTHERN NEVADA SE TO NW NEW MEXICO. DOWNSTREAM, A BROAD TROF WAS MOVING ACROSS THE EASTERN UNITED STATES. @ 700 HPA, 2 DEG C OF WARMING OCCURRED AT KDDC BETWEEN 22.12Z AND 23.12Z SYNOPTIC FLIGHTS AND AT A FAIRLY WARM TEMP OF 15 DEG C THIS MORNING. @ 850 HPA, KDDC WAS AT 26 DEG C, WHICH IS ABOVE THE 75TH PERCENTILE. AT THE SFC, A LOW PRESSURE CENTER WAS LOCATED ACROSS FAR SW KANSAS. AN OUTFLOW BOUNDARY WAS DRAPED ACROSS THE FORECAST AREA OF RESPONSIBILITY. INVEST 98E WAS LOCATED 800 MILES SSW OF THE SOUTHERN TIP OF BAJA CALIFORNIA. INVEST 98L WAS LOCATED A COUPLE HUNDRED MILES SSE OF THE CAPE VERDE ISLANDS. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 200 PM CDT TUE JUL 23 2013 TONIGHT: NEAR TERM FORECAST CONCERN IS CONVECTION THIS AFTERNOON/EVENING. WSR- 88D AND SURFACE OBSERVATIONS SHOW A FEW BOUNDARIES ACROSS THE REGION THIS AFTERNOON. ONE IS A "COLD FRONT"/OUTFLOW BOUNDARY THIS IS ROUGHLY LOCATED FROM NESS CITY SE TO PRATT. A NONDESCRIPT DRYLINE IS THE OTHER BOUNDARY FARTHER WEST. THE INTERSECTION OF THESE TWO DENSITY GRADIENTS SHOULD BE WHERE CONVECTION INITIATES. THE MOST RECENT HRRR IS SHOWING AN ISOLATED STORM DEVELOPING JUST NORTHEAST OF DODGE CITY (MUCH LIKE YESTERDAY) AND THEN INDICATING THIS ACTIVITY DRIFTING OFF TO THE SE AS THE EARLY EVENING WEARS ON. THE NAM IS IN FAIR AGREEMENT WITH THIS SOLUTION. THE STORMS MAY BECOME SEVERE AS WELL AS 1-8 KM BULK SHEAR IS STRONGER THAN YESTERDAY...PLUS DEWPOINTS ARE STILL RUNNING FAIRLY HIGH, WHICH WILL CREATE ABOUT 1500-2000 J/KG OF SBCAPE. MODELS ALSO SHOW SOME DCAPE AS THE ATMOSPHERE BECOMES WELL MIXED. AS A RESULT, HAVE TWEAKED THE HWO WITH THE THREATS OF QUARTER SIZE HAIL, 60 MPH OUTFLOW, AND LIGHTNING AS THE MAIN CONCERNS. THIS ACTIVITY WILL CLEAR THE AREA LATER THIS EVENING AS THE FRONT SINKS SOUTHWARD. OVERNIGHT LOWS WILL BE IN THE 60S DEG F AND 70S DEG F. UPSLOPE STRATUS WILL BE POSSIBLE ON THE BACKSIDE OF THE LOW LEVEL PRESSURE PERTURBATION WITH UPSLOPE WINDS IN THE SFC-850 HPA LAYER. TOMORROW: AN UPSLOPE FLOW PATTERN IS EXPECTED TOMORROW IN THE WAKE OF THE AFOREMENTIONED BOUNDARY. MAXIMUMS WILL BE "COOLER" THAN COMPARED TO TODAY WITH VALUES IN THE UPPER 80S DEG F TO LOWER 90S DEG F. 23.12Z NAM SOLUTION IS WARMER COMPARED TO OTHER GUIDANCE, BUT THIS MIGHT BE A BIT OVERDONE. WILL USE THE ECMWF FOR NOW. OROGRAPHIC CONVECTION IS POSSIBLE IN THE UPSLOPE FLOW REGIME TOMORROW ACROSS EASTERN COLORADO. WILL CARRY SLIGHT PRECIPITATION PROBABILITY PERCENTAGE POINTS FOR FAR WEST KANSAS THROUGH 00Z TOMORROW NIGHT. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 353 PM CDT TUE JUL 23 2013 THE SYSTEM THAT MOVED WESTWARD ALONG THE SOUTHERN EDGE OF THE UPPER LEVEL RIDGE LAST WEEK WAS LOCATED NEAR THE CALIFORNIA COAST TODAY AND IS POISED TO MOVE BACK EASTWARD ON THE NORTHERN SIDE OF THE UPPER LEVEL RIDGE. BY WEDNESDAY NIGHT AND THURSDAY, THIS SYSTEM WILL BE APPROACHING FROM THE WEST. A STATIONARY FRONT WILL BE LOCATED OVER THE SOUTHERN PLAINS, WITH UPSLOPE FLOW AND ABUNDANT LOW LEVEL MOISTURE ON THE COOL SIDE OF THE FRONT OVER WESTERN KANSAS. WE ARE EXPECTING THUNDERSTORMS TO DEVELOP OVER COLORADO AND THEN EXPAND INTO A LARGER CLUSTER OF STORMS OVER THE PLAINS. THE EXACT POSITIONING OF THIS STORM CLUSTER IS UNCERTAIN. SO FOR NOW, RAIN CHANCES WERE KEPT AT 40-50% FOR LATE WEDNESDAY NIGHT INTO THURSDAY NIGHT. AFTER THE AFOREMENTIONED SYSTEM PASSES BY FRIDAY MORNING, A BREAK IN PRECIPITATION IS EXPECTED FRIDAY AND SATURDAY, WITH CONTINUED COOL WEATHER (HIGHS MAINLY IN THE 80S AND LOWS IN THE 60S). BY THE WEEKEND, THE MID TO UPPER LEVEL FLOW WILL BECOME MORE WEST-NORTHWESTERLY AGAIN, RESULTING IN RENEWED WEAK SURFACE LEE TROUGHING AND WARM/MOIST ADVECTION INTO WESTERN KANSAS. THEREFORE, THERE ARE CHANCES OF THUNDERSTORMS AGAIN BY SATURDAY NIGHT INTO MONDAY, WITH CONTINUED COOL WEATHER (HIGHS MAINLY 80S). && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING) ISSUED AT 612 PM CDT TUE JUL 23 2013 WIDELY SCATTERED THUNDERSTORMS WILL BE POSSIBLE NEAR DODGE CITY THROUGH 02Z. BASED ON SURFACE OBSERVATIONS AND 18Z NAM BUFR SOUNDINGS THE BASES OF THESE STORMS ARE EXPECTED TO BE AT OR ABOVE 7000 FT. THUNDERSTORMS ARE EXPECTED TO MOVE OUT OF THE DODGE CITY AREA BY 02Z AS A COLD FRONT MOVES SOUTH ACROSS SOUTHWESTERN KANSAS. AS THIS FRONT PASSES EARLY THIS EVENING A GUSTY NORTH/NORTHEAST WIND AT AROUND 15KTS WILL BE POSSIBLE THROUGH THE OVERNIGHT PERIOD. THERE WILL ALSO BE SOME IFR STATUS POSSIBLE TOWARDS DAYBREAK, HOWEVER FOG DOES NOT APPEAR TO BE A SIGNIFICANT ISSUE GIVEN THE MIXING IN THE LOWER LEVELS. && .PRELIMINARY POINT TEMPS/POPS... DDC 67 91 69 86 / 20 10 40 50 GCK 67 90 68 86 / 10 10 50 50 EHA 67 91 68 87 / 10 20 50 50 LBL 69 93 69 89 / 20 10 40 50 HYS 66 88 68 84 / 20 10 40 50 P28 71 90 71 89 / 20 10 40 50 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...SUGDEN SHORT TERM...SUGDEN LONG TERM...FINCH AVIATION...BURGERT
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
215 PM EDT MON JUL 22 2013 .UPDATE... ISSUED AT 200 PM EDT MON JUL 22 2013 UPDATED THE FORECAST TO BETTER TIME THE RAIN BAND THROUGH THE CWA AND ALLOW FOR MORE CONVECTION TO DEVELOP IN ITS WAKE. ALSO...TWEAKED THE TEMP AND DEWPOINT TRACES PER THE LATEST OBS AND TRENDS...AS WELL AS TOUCHED UP FORECAST HIGHS. UPDATED GRIDS HAVE BEEN SENT TO THE NDFD AND WEB SERVERS ALONG WITH A FRESHENED ZFP. UPDATE ISSUED AT 1025 AM EDT MON JUL 22 2013 13Z SFC ANALYSIS SHOWS A DEVELOPING AREA OF LOW PRESSURE MOVING INTO THE OHIO VALLEY. THIS DEVELOPMENT IS OCCURRING DUE TO AN INBOUND AND SHARPENING 500 MB SHORT WAVE THAT WILL CROSS NORTHERN KENTUCKY LATER TODAY. AS SUCH...IT IS ALSO BRINGING WITH IT A LARGE CLUSTER OF MAINLY MODERATE SHOWERS ALONG WITH A COUPLE OF EMBEDDED THUNDERSTORMS. THE RAIN AREA IS POISED TO ENTER OUR CWA AND PROGRESS FROM WEST TO EAST THROUGH THE REST OF THE MORNING. THE LATEST HRRR DOES SHOW THIS AREA BREAKING UP TOWARD NOON AND MORE SCATTERED CONVECTION DEVELOPING THROUGHOUT EAST KENTUCKY... THEREAFTER. EXPECT THIS SECONDARY CONVECTION...TAPPING INTO HIGH PW AIR IN PLACE...TO HAVE THE BEST CHANCE OF PRODUCING EXCESSIVE RAINS...TRAINING...AND THE POTENTIAL FOR LOCALIZED FLASH FLOODING. HAVE UPDATED THE GRIDS TO REFLECT THIS TYPE OF EVOLUTION TO THE POPS...WX...AND QPF. ALSO...BUMPED UP TEMPS IN THE EAST A NOTCH DUE TO A DECENT SUNNY PATCH MOVING THROUGH ATTM AHEAD OF THE INBOUND MASS OF SHOWERS. MEANWHILE...TOOK DOWN THE MAX TEMPS IN THE WEST A TAD FOR THE OPPOSITE REASON. OTHERWISE...THE THREAT FOR DOWNPOURS LOOKS GOOD FOR MOST OF THE REGION SO WILL CONTINUE THE FFA AND MENTION OF LOCALLY HEAVY RAIN IN THE ZONES/HWO THROUGH THE EVENING. FOR TONIGHT...WILL HAVE TO LOOK CLOSELY AT THE POTENTIAL FOR DENSE FOG IF WE MANAGE TO GET MUCH CLEARING AFTER THE RAINS OF TODAY. UPDATES HAVE BEEN SENT TO THE NDFD AND WEB SERVERS. UPDATE ISSUED AT 753 AM EDT MON JUL 22 2013 UPSTREAM RADARS SHOW A LARGE CLUSTER OF SHOWERS AND STORMS MAKING A BEELINE TOWARD EAST KENTUCKY. AS A RESULT...WE NUDGED POPS UP INTO THE CATEGORICAL RANGE FOR ALL BUT OUR EASTERNMOST COUNTIES AS RECENT HRRR RUNS SHOW THE SHOWERS BREAKING UP SOME AS THEY HEAD EAST OF JKL. UPDATE ISSUED AT 655 AM EDT MON JUL 22 2013 MODIFIED THE FORECAST GRIDS TO REFLECT SLOWER ONSET OF PRECIPITATION EARLY THIS MORNING. ALSO ISSUED AN UPDATE TO THE FLASH FLOOD WATCH. THE NEW ZONES WILL BE ISSUED SHORTLY. && .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 310 AM EDT MON JUL 22 2013 MODELS IN PRETTY GOOD AGREEMENT ON THE OVERALL WEATHER PATTERN FOR THE NEXT COUPLE OF DAY. CONSENSUS VIEW IS FOR WIDESPREAD SHOWERS AND STORMS TO DEVELOP EARLY THIS MORNING AND PERSIST THROUGH THE END OF THE DAY ON TUESDAY. THE PRIMARY CONCERN WILL BE LOCALLY HEAVY RAINFALL AND FLOODING. WITH A DEEP LAYER OF MOISTURE IN THE ATMOSPHERE AND WEAK MIDDLE AND UPPER LEVEL WINDS...ANY STORMS THAT FORM WILL BE SLOW MOVING AND WILL HAVE THE POTENTIAL PRODUCE HEAVY RAINFALL OVER VERY LOCALIZED AREAS...WHICH COULD LEAD TO FLASH FLOODING. HIGH TEMPERATURES TODAY AND TOMORROW WILL BE SLIGHTLY BELOW NORMAL...DUE TO THE INFLUENCE OF WIDESPREAD CLOUD COVER AND SHOWER AND STORM ACTIVITY. A FLASH FLOOD WATCH REMAINS IN EFFECT FOR ALL OF EASTERN KENTUCKY THROUGH MONDAY EVENING. .LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY) ISSUED AT 310 AM EDT MON JUL 22 2013 LONGWAVE TROUGH NOW BECOMING ESTABLISHED OVER THE EASTERN U.S. WILL REMAIN IN PLACE THROUGH THE LONG TERM PERIOD. AT THE SURFACE...A COLD FRONT WILL SLIP TO OUR SOUTH TUESDAY NIGHT AND WEDNESDAY WITH HIGH PRESSURE BUILDING IN BEHIND. WHILE THE DEEPER MOISTURE WILL BE TO OUR SOUTH BY TUESDAY NIGHT...THE FRONT WILL LIKELY KICK OFF ISOLATED TO SCATTERED SHOWERS/STORMS AS IT PASSES. THE HIGH PRESSURE SYSTEM WILL THEN USHER IN A MUCH DRIER AIR MASS FOR THURSDAY AND FRIDAY. IN FACT...IT APPEARS DEWPOINTS MAY EVEN TUMBLE AS LOW AS THE UPPER 50S BY THURSDAY AFTERNOON...WHICH WILL FEEL VERY NICE AFTER THE RECENT PROLONGED BOUT OF 70 DEGREE DEWPOINTS. FORECASTER CONFIDENCE THEN FALLS AS WE HEAD INTO THE WEEKEND. THE UPPER LEVEL TROUGH WILL DIG BACK IN AFTER A BRIEF RELAXATION FORCING A SURFACE FRONT SOUTHWARD INTO THE OHIO VALLEY. THE 22/00Z ECMWF WANTS TO HOLD A PIECE OF THE UPPER TROUGH BACK OVER THE PLAINS... WHILE THE 22/00Z GFS/GEM/UKMET DO NOT. THIS RESULTS IN A WETTER SOLUTION IN THE GFS/GEM/UKMET MODELS WHILE THE ECMWF IS SLOWER TO BRING IN ANY PRECIP. AS SUCH...WILL TREND BACK A LITTLE WITH POPS TO REFLECT THE ADDED UNCERTAINTY BUT STILL OFFER SCATTERED SHOWERS AND STORMS THROUGHOUT THE WEEKEND. DAYTIME HIGHS WILL CHANGE LITTLE THROUGH THE PERIOD...REACHING THE LOW TO MID 80S EACH DAY. OVERNIGHT LOWS WILL RESPOND TO THE FALLING DEWPOINTS LATE IN THE WEEK...FALLING FROM THE MID TO UPPER 60S TUESDAY NIGHT BACK INTO THE UPPER 50S TO LOW 60S THURSDAY NIGHT. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 215 PM EDT MON JUL 22 2013 A BAND OF MODERATE TO HEAVY SHOWERS WILL LIFT NORTHEAST THROUGH THE REST OF THE CWA OVER THE NEXT COUPLE OF HOURS. WITH THIS...THE LOWEST VIS AND CIGS WILL OCCUR...DOWN TO LIFR FOR A TIME. OTHERWISE...MORE SCATTERED CONVECTION WILL OCCUR THROUGH THE EVENING SO HAVE CONTINUED A VCTS PERIOD THROUGH 04Z FOR MOST SITES. DO EXPECT SOME CLEARING LATER TONIGHT AND THIS SHOULD BE ENOUGH TO ACTIVATE A FOGGY REGIME. ACCORDINGLY...HAVE TAKEN THE VIS DOWN TO LIFR AT SME AND LOZ TOWARD DAWN TUESDAY AND MVFR AT JKL FOR A TIME. MORE STORMS WILL BE POSSIBLE ON TUESDAY...BUT DO NOT EXPECT THEM TO BECOME PREVALENT UNTIL LATER IN THE AFTERNOON SO HAVE KEPT THEIR MENTION OUT OF THE FORECAST THROUGH 18Z TUESDAY. BREEZY SOUTHWEST WINDS WILL SETTLE DOWN THIS EVENING AND STAY RATHER LIGHT AND VARIABLE INTO TUESDAY. && .JKL WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH UNTIL 8 PM EDT THIS EVENING FOR KYZ044-050>052- 058>060-068-069-079-080-083>088-104-106>120. && $$ UPDATE...GREIF SHORT TERM...AR LONG TERM...ABE AVIATION...GREIF
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
1025 AM EDT MON JUL 22 2013 .UPDATE... ISSUED AT 1025 AM EDT MON JUL 22 2013 13Z SFC ANALYSIS SHOWS A DEVELOPING AREA OF LOW PRESSURE MOVING INTO THE OHIO VALLEY. THIS DEVELOPMENT IS OCCURRING DUE TO AN INBOUND AND SHARPENING 500 MB SHORT WAVE THAT WILL CROSS NORTHERN KENTUCKY LATER TODAY. AS SUCH...IT IS ALSO BRINGING WITH IT A LARGE CLUSTER OF MAINLY MODERATE SHOWERS ALONG WITH A COUPLE OF EMBEDDED THUNDERSTORMS. THE RAIN AREA IS POISED TO ENTER OUR CWA AND PROGRESS FROM WEST TO EAST THROUGH THE REST OF THE MORNING. THE LATEST HRRR DOES SHOW THIS AREA BREAKING UP TOWARD NOON AND MORE SCATTERED CONVECTION DEVELOPING THROUGHOUT EAST KENTUCKY... THEREAFTER. EXPECT THIS SECONDARY CONVECTION...TAPPING INTO HIGH PW AIR IN PLACE...TO HAVE THE BEST CHANCE OF PRODUCING EXCESSIVE RAINS...TRAINING...AND THE POTENTIAL FOR LOCALIZED FLASH FLOODING. HAVE UPDATED THE GRIDS TO REFLECT THIS TYPE OF EVOLUTION TO THE POPS...WX...AND QPF. ALSO...BUMPED UP TEMPS IN THE EAST A NOTCH DUE TO A DECENT SUNNY PATCH MOVING THROUGH ATTM AHEAD OF THE INBOUND MASS OF SHOWERS. MEANWHILE...TOOK DOWN THE MAX TEMPS IN THE WEST A TAD FOR THE OPPOSITE REASON. OTHERWISE...THE THREAT FOR DOWNPOURS LOOKS GOOD FOR MOST OF THE REGION SO WILL CONTINUE THE FFA AND MENTION OF LOCALLY HEAVY RAIN IN THE ZONES/HWO THROUGH THE EVENING. FOR TONIGHT...WILL HAVE TO LOOK CLOSELY AT THE POTENTIAL FOR DENSE FOG IF WE MANAGE TO GET MUCH CLEARING AFTER THE RAINS OF TODAY. UPDATES HAVE BEEN SENT TO THE NDFD AND WEB SERVERS. UPDATE ISSUED AT 753 AM EDT MON JUL 22 2013 UPSTREAM RADARS SHOW A LARGE CLUSTER OF SHOWERS AND STORMS MAKING A BEELINE TOWARD EAST KENTUCKY. AS A RESULT...WE NUDGED POPS UP INTO THE CATEGORICAL RANGE FOR ALL BUT OUR EASTERNMOST COUNTIES AS RECENT HRRR RUNS SHOW THE SHOWERS BREAKING UP SOME AS THEY HEAD EAST OF JKL. UPDATE ISSUED AT 655 AM EDT MON JUL 22 2013 MODIFIED THE FORECAST GRIDS TO REFLECT SLOWER ONSET OF PRECIPITATION EARLY THIS MORNING. ALSO ISSUED AN UPDATE TO THE FLASH FLOOD WATCH. THE NEW ZONES WILL BE ISSUED SHORTLY. && .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 310 AM EDT MON JUL 22 2013 MODELS IN PRETTY GOOD AGREEMENT ON THE OVERALL WEATHER PATTERN FOR THE NEXT COUPLE OF DAY. CONSENSUS VIEW IS FOR WIDESPREAD SHOWERS AND STORMS TO DEVELOP EARLY THIS MORNING AND PERSIST THROUGH THE END OF THE DAY ON TUESDAY. THE PRIMARY CONCERN WILL BE LOCALLY HEAVY RAINFALL AND FLOODING. WITH A DEEP LAYER OF MOISTURE IN THE ATMOSPHERE AND WEAK MIDDLE AND UPPER LEVEL WINDS...ANY STORMS THAT FORM WILL BE SLOW MOVING AND WILL HAVE THE POTENTIAL PRODUCE HEAVY RAINFALL OVER VERY LOCALIZED AREAS...WHICH COULD LEAD TO FLASH FLOODING. HIGH TEMPERATURES TODAY AND TOMORROW WILL BE SLIGHTLY BELOW NORMAL...DUE TO THE INFLUENCE OF WIDESPREAD CLOUD COVER AND SHOWER AND STORM ACTIVITY. A FLASH FLOOD WATCH REMAINS IN EFFECT FOR ALL OF EASTERN KENTUCKY THROUGH MONDAY EVENING. .LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY) ISSUED AT 310 AM EDT MON JUL 22 2013 LONGWAVE TROUGH NOW BECOMING ESTABLISHED OVER THE EASTERN U.S. WILL REMAIN IN PLACE THROUGH THE LONG TERM PERIOD. AT THE SURFACE...A COLD FRONT WILL SLIP TO OUR SOUTH TUESDAY NIGHT AND WEDNESDAY WITH HIGH PRESSURE BUILDING IN BEHIND. WHILE THE DEEPER MOISTURE WILL BE TO OUR SOUTH BY TUESDAY NIGHT...THE FRONT WILL LIKELY KICK OFF ISOLATED TO SCATTERED SHOWERS/STORMS AS IT PASSES. THE HIGH PRESSURE SYSTEM WILL THEN USHER IN A MUCH DRIER AIR MASS FOR THURSDAY AND FRIDAY. IN FACT...IT APPEARS DEWPOINTS MAY EVEN TUMBLE AS LOW AS THE UPPER 50S BY THURSDAY AFTERNOON...WHICH WILL FEEL VERY NICE AFTER THE RECENT PROLONGED BOUT OF 70 DEGREE DEWPOINTS. FORECASTER CONFIDENCE THEN FALLS AS WE HEAD INTO THE WEEKEND. THE UPPER LEVEL TROUGH WILL DIG BACK IN AFTER A BRIEF RELAXATION FORCING A SURFACE FRONT SOUTHWARD INTO THE OHIO VALLEY. THE 22/00Z ECMWF WANTS TO HOLD A PIECE OF THE UPPER TROUGH BACK OVER THE PLAINS... WHILE THE 22/00Z GFS/GEM/UKMET DO NOT. THIS RESULTS IN A WETTER SOLUTION IN THE GFS/GEM/UKMET MODELS WHILE THE ECMWF IS SLOWER TO BRING IN ANY PRECIP. AS SUCH...WILL TREND BACK A LITTLE WITH POPS TO REFLECT THE ADDED UNCERTAINTY BUT STILL OFFER SCATTERED SHOWERS AND STORMS THROUGHOUT THE WEEKEND. DAYTIME HIGHS WILL CHANGE LITTLE THROUGH THE PERIOD...REACHING THE LOW TO MID 80S EACH DAY. OVERNIGHT LOWS WILL RESPOND TO THE FALLING DEWPOINTS LATE IN THE WEEK...FALLING FROM THE MID TO UPPER 60S TUESDAY NIGHT BACK INTO THE UPPER 50S TO LOW 60S THURSDAY NIGHT. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 753 AM EDT MON JUL 22 2013 PRECIPITATION ONSET THIS MORNING WILL OCCUR BETWEEN 1430Z AND 16Z AT THE TAF SITES AS A LARGE CLUSTER OF SHOWERS AND STORMS PROGRESSES EASTWARD ACROSS THE REGION. EXPECTING MVFR CONDITIONS TO PREVAIL AT THE TAF SITES ONCE THE RAIN BEGINS TO FALL. THE CLUSTER OF SHOWERS WILL SHIFT EAST DURING THE AFTERNOON WITH A LESS WELL DEFINED THREAT FOR SHOWERS AND STORMS FROM LATE AFTERNOON INTO THE EVENING HOURS. LOW CLOUDS AND FOG WILL THEN BECOME A HAZARD TO AVIATION LATE TONIGHT. && .JKL WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH UNTIL 8 PM EDT THIS EVENING FOR KYZ044-050>052- 058>060-068-069-079-080-083>088-104-106>120. && $$ UPDATE...GREIF SHORT TERM...AR LONG TERM...ABE AVIATION...AR/ABE
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
643 AM EDT MON JUL 22 2013 ...Updated Aviation Discussion... .FORECAST UPDATE... Issued at 640 AM EDT Mon Jul 22 2013 A solid line of showers has formed along a Theta-E ridge running from NW TN to FTK. A broad meso has formed along that line and is getting ready to move into our southwest forecast area. KHPX radar indicates a nice low-level jet, with winds of 35-40 knots at ~2500 feet. Tried blending ongoing radar trends with RAP forecasts for this Theta-E ridge over the next couple of hours to get a PoP forecast. Updated products are out. && .SHORT TERM (Today through Tuesday)... Issued at 315 AM EDT Sun Jul 21 2013 Pronounced shortwave trough, centered now along the northern MO/IL border will move into our region today. Combined with a tropical airmass in place, and we should see another round of showers and storms this morning into the afternoon. Seeing one line of storms forming over the MO/AR border into western KY and another one closer to a stationary front to our north, along the central IL/IN border. With additional storms in the forecast, have decided to lift a flash flood watch for a portion of our forecast area. The Bluegrass has the lowest flash flood guidance, with 3-hour guidance between 1.5 and 2 inches. Areal average QPF for that region is around an inch, but it easily could be higher with any slow-moving heavy storms. Airmass looks too tropical for severe weather, though we do look to have a weak low moving up the Ohio Valley ahead of the upper level feature, so will have to watch for some rotation in any storms that form. We should see a break in the precip tonight, but the airmass does not dry out until after this period, so cannot rule out additional isolated storms. Another wave looks to come across the area Tuesday, bringing enhanced rain chances once more. Coverage should be more limited than today, but soundings favor a better chance for stronger storms, with gusty winds and hail as the main threats. Temperatures today will depend on how quick the precip exits our region this afternoon. Have gone with higher values over the west, mid 80s compared with around 80 for the east. Temperatures tonight should be similar to this morning, with no real change in airmass. Readings should warm back into the upper 80s for Tuesday. .LONG TERM (Tuesday Night through Sunday)... Issued at 300 AM EDT Mon Jul 22 2013 Longwave 500mb upper air pattern early Wednesday will feature a broad ridge centered over the Intermountain West and a robust trough centered over the Great Lakes. Northwest flow will influence the Lower Ohio Valley. Ultimately, this pattern will bring pleasant, seasonably cool weather and relatively low dewpoints, especially for the period Wednesday through Friday. Several weak waves may move southeast across the Lower Ohio Valley Tuesday through Saturday. The first will cross the Ohio River Tuesday evening. High pressure over the upper midwest will build in behind a cold front that will move across the Commonwealth during the early morning hours Wednesday. Scattered convection will likely end from the north to the south during the morning hours Wednesday as drier air arrives from the northwest. Think that Wednesday afternoon will stay dry with noticeably less humid conditions. Northwesterly winds behind this front will lower dewpoints into the upper 50s by Wednesday evening. High pressure will build across the northern Ohio Valley Thursday and continue through Friday. Expect mostly clear skies with comfortable nights. Highs will stay in the mid 80s with lows well down into the 60s. The proximity of the surface high to our north will lead to light northeasterly to easterly winds through early Saturday. For several days now, long range guidance has advertised a quick return of moisture ahead of an upper wave on Saturday. Showers and storms may approach as early as Saturday morning and continue during the day Saturday just ahead of a progressive 500mb trough. Temperatures still will stay relatively mild Saturday and Sunday, with highs in the 80s and upper 60s at night. Expect clearing Sunday with dry conditions. && .AVIATION (12Z TAF Update)... Issued at 645 AM EDT Mon Jul 22 2013 Very moist atmosphere remains in place ahead of an upper level disturbance forecast to move through the region this afternoon. Have tried to time storms based on RAP forecasts for now, with periods of at least MVFR conditions. Rain chances should become more limited when that trough comes through so have kept in some VFR cigs by mid/late afternoon with no storms. We may see some light fog by the end of the period, given no real change in airmass and muggy conditions, but will leave out of the forecast for now to keep the number of lines in the TAFs down. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...NONE. KY...FLASH FLOOD WATCH THROUGH THIS EVENING FOR KYZ036-037-041>043- 048-049-057. $$ Update...........RJS Short Term.......RJS Long Term........JSD Aviation.........RJS
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
318 AM EDT MON JUL 22 2013 .SHORT TERM (Today through Tuesday)... Issued at 315 AM EDT Sun Jul 21 2013 Pronounced shortwave trough, centered now along the northern MO/IL border will move into our region today. Combined with a tropical airmass in place, and we should see another round of showers and storms this morning into the afternoon. Seeing one line of storms forming over the MO/AR border into western KY and another one closer to a stationary front to our north, along the central IL/IN border. With additional storms in the forecast, have decided to lift a flash flood watch for a portion of our forecast area. The Bluegrass has the lowest flash flood guidance, with 3-hour guidance between 1.5 and 2 inches. Areal average QPF for that region is around an inch, but it easily could be higher with any slow-moving heavy storms. Airmass looks too tropical for severe weather, though we do look to have a weak low moving up the Ohio Valley ahead of the upper level feature, so will have to watch for some rotation in any storms that form. We should see a break in the precip tonight, but the airmass does not dry out until after this period, so cannot rule out additional isolated storms. Another wave looks to come across the area Tuesday, bringing enhanced rain chances once more. Coverage should be more limited than today, but soundings favor a better chance for stronger storms, with gusty winds and hail as the main threats. Temperatures today will depend on how quick the precip exits our region this afternoon. Have gone with higher values over the west, mid 80s compared with around 80 for the east. Temperatures tonight should be similar to this morning, with no real change in airmass. Readings should warm back into the upper 80s for Tuesday. .LONG TERM (Tuesday Night through Sunday)... Issued at 300 AM EDT Mon Jul 22 2013 Longwave 500mb upper air pattern early Wednesday will feature a broad ridge centered over the Intermountain West and a robust trough centered over the Great Lakes. Northwest flow will influence the Lower Ohio Valley. Ultimately, this pattern will bring pleasant, seasonably cool weather and relatively low dewpoints, especially for the period Wednesday through Friday. Several weak waves may move southeast across the Lower Ohio Valley Tuesday through Saturday. The first will cross the Ohio River Tuesday evening. High pressure over the upper midwest will build in behind a cold front that will move across the Commonwealth during the early morning hours Wednesday. Scattered convection will likely end from the north to the south during the morning hours Wednesday as drier air arrives from the northwest. Think that Wednesday afternoon will stay dry with noticeably less humid conditions. Northwesterly winds behind this front will lower dewpoints into the upper 50s by Wednesday evening. High pressure will build across the northern Ohio Valley Thursday and continue through Friday. Expect mostly clear skies with comfortable nights. Highs will stay in the mid 80s with lows well down into the 60s. The proximity of the surface high to our north will lead to light northeasterly to easterly winds through early Saturday. For several days now, long range guidance has advertised a quick return of moisture ahead of an upper wave on Saturday. Showers and storms may approach as early as Saturday morning and continue during the day Saturday just ahead of a progressive 500mb trough. Temperatures still will stay relatively mild Saturday and Sunday, with highs in the 80s and upper 60s at night. Expect clearing Sunday with dry conditions. && .AVIATION (06Z TAF Update)... Issued at 135 AM EDT Mon Jul 22 2013 Very moist atmosphere remains in place ahead of an upper level disturbance forecast to move through the region this afternoon. Have tried to time storms based on RAP forecasts for now, giving a brief lull to the sites early than more storms. That same moisture likely also will cause brief cig/vsby issues despite storm forecast. Rain chances should become more limited when that trough comes through so have kept in some VFR cigs by mid/late afternoon with no storms. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...NONE. KY...FLASH FLOOD WATCH THROUGH THIS EVENING FOR KYZ036-037-041>043- 048-049-057. $$ Short Term.......RJS Long Term........JSD Aviation.........RJS
AREA FORECAST DISCUSSION
NWS JACKSON KY
201 AM EDT MON JUL 22 2013 .UPDATE... ISSUED AT 200 AM EDT MON JUL 22 2013 INGESTED THE LATEST OBSERVATIONAL DATA INTO THE FORECAST GRIDS TO ESTABLISH NEW TRENDS. OVERALL THE INHERITED FORECAST WAS IN GOOD SHAPE...HOWEVER...WILL BE ISSUING A QUICK UPDATE TO REMOVE SOME OUTDATED WORDING FROM THE ZONE FORECAST TEXT PRODUCT. UPDATE ISSUED AT 932 PM EDT SUN JUL 21 2013 TRAINING STORMS WERE STILL ONGOING OVER THE NORTHERN SECTION OF THE CWA AS WAS DISCUSSED IN THE PREVIOUS UPDATE. WENT AHEAD AND EXTENDED SCT POPS FOR THE NEXT COUPLE OF HOURS...MAINLY ALONG THE MOUNTAIN PARKWAY WHERE MAIN SHOWER ACTIVITY HAS BEEN LOCATED. LATEST RADAR TRENDS ARE SHOWING BEST SHOWER ACTIVITY DIMINISHING...BUT LOW END CHANCE POPS ARE STILL WARRANTED FOR ONGOING ACTIVITY AND POTENTIAL REDEVELOPMENT. EXCESS MOISTURE ACROSS THE NORTH AND EAST HAS LED TO FOG DEVELOPMENT AT THE NWS OFFICE. AS RAIN CONTINUES TO DIMINISH...EXPECT FOG TO PREVAIL THROUGH MUCH OF THE NIGHT BEFORE NEXT AREA OF WIDESPREAD SHOWERS AND THUNDERSTORMS MOVES IN BY EARLY MORNING. MADE THIS UPDATE TO THE WEATHER GRIDS AS WELL...ADDING FOG IN FOR VALLEYS MAINLY IN THE EASTERN CWA. UPDATE ISSUED AT 544 PM EDT SUN JUL 21 2013 A CONTINUED LINE OF SCT TRAINING STORMS EXTENDS ACROSS THE NORTHERN HALF OF THE CWA ALONG SOME WEAK HORIZONTAL BOUNDARY. PREVIOUS FORECAST HAD SHOWERS ENDING OVER THE NW...BUT SO LONG AS THIS BOUNDARY REMAINS IN PLACE...EXPECT ISOLATED TO SCT SHOWERS AND THUNDERSTORMS TO CONTINUE OVER THIS AREA FOR THE NEXT COUPLE HOURS. ALSO ADDED IN SOME ISOLATED POPS FOR SOME AREAS OVERNIGHT...MAINLY BEFORE MIDNIGHT...BASED ON LATEST HI RES MODEL RUNS AND CURRENT FORECAST TRENDS. ADDED CURRENT OBSERVATIONS INTO ONGOING FORECAST AS WELL. && .SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT) ISSUED AT 325 PM EDT SUN JUL 21 2013 MORNING SHOWERS AND THUNDERSTORMS HAVE SHIFTED OFF TO THE SOUTH...BUT THANKS TO SOME HEATING ACROSS THE EAST...ADDITIONAL SHOWERS AND THUNDERSTORMS HAVE DEVELOPED TO THE EAST OF JACKSON...TOWARDS PRESTONSBURG AND INEZ. THIS ACTIVITY WILL SLOWLY PUSH EAST THROUGH THE REST OF THE AFTERNOON AND EVENING BEFORE EXITING EASTERN KENTUCKY. IN THE WAKE OF THIS ACTIVITY IT LOOKS LIKE A FAIRLY QUIET MID TO LATE EVENING IS ANTICIPATED AS SUBSIDENCE AHEAD OF THE APPROACHING TROUGH AXIS ACROSS THE CENTRAL PLAINS TAKES HOLD. HRRR IS IN LINE WITH CONDITIONS QUIETING DOWN THIS EVENING. WITH THE SYNOPTIC FORCING OVERSPREADING THE AREA LATE TONIGHT INTO TOMORROW MORNING...WILL BRING A PERIOD OF HIGH POPS BACK INTO THE FORECAST. GIVEN THE RAIN THIS AFTERNOON...AND POTENTIAL HEAVY RAIN WITH THE SYNOPTIC FEATURE LATE TONIGHT...GOING TO CONTINUE ON WITH THE FLASH FLOOD WATCH. IN FACT...THE NAM SPITS OUT MORE THAN AN INCH OF RAIN ACROSS A GOOD CHUNK OF THE AREA LATE TONIGHT AND TOMORROW...SO THE POTENTIAL FOR HEAVY RAIN CONTINUES. THIS IS ESPECIALLY TRUE WITH PWATS SITTING UP AROUND 1.8-2.0 INCHES. GOOD SHOWER AND THUNDERSTORM COVERAGE SHOULD CONTINUE TOMORROW AS THE MID LEVEL WAVE PUSHES EAST ACROSS THE AREA. COVERAGE SHOULD DIMINISH TOMORROW EVENING INTO THE NIGHTTIME HOURS...ALTHOUGH SHOWERS AND THUNDERSTORMS COULD CONTINUE THROUGH TOMORROW NIGHT AS WELL. CERTAINLY AN ACTIVE PERIOD SETTING UP. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 325 PM EDT SUN JUL 21 2013 THE MODELS ESSENTIALLY AGREE ON THE GENERAL EVOLUTION OF MID LEVEL TROUGHING OVER THE OHIO VALLEY AND GREAT LAKES THROUGH THE EXTENDED. HOWEVER...THERE REMAINS MUCH DISAGREEMENT WITH RESPECT TO TIMING AND TRACKS OF THE VARIOUS SHORTWAVES THAT WILL MOVE THROUGH THE AREA LATER THIS WEEK AND INTO NEXT WEEKEND. THE ECMWF TAKES A KEY ONE OF THESE INTO THE OHIO VALLEY ON WEDNESDAY HELPING TO BOTTOM OUT THIS FIRST ITERATION OF A TROUGH. ANOTHER FOLLOWS...THOUGH...RIGHT ON THE HEELS OF THE FIRST...THAT NIGHT WHICH WILL SERVE TO SHIFT THE TROUGH EAST OF KENTUCKY ALLOWING SOME BRIEF HEIGHT RISES INTO THE CWA TO CLOSE OUT THE WORK WEEK. HEIGHTS WILL START TO FALL AGAIN ON SATURDAY WHEN A RATHER STRONG WAVE WILL MOVE DUE EAST OUT OF THE CENTRAL PLAINS AND TOWARD THE OHIO VALLEY. UNLIKE YESTERDAY...THIS FEATURE HAS GAINED SOME SUPPORT FROM THE GFS...JUST NOT AS STRONG. IN CONJUNCTION WITH THIS SATURDAY WAVE...ANOTHER SWEEPS DOWN FROM SOUTH CENTRAL CANADA LATER THAT NIGHT INTO EARLY SUNDAY RESTORING A DEEP TROUGH OVER THE REGION. GIVEN THE SIMILARITIES IN THE OVERALL PATTERN...WILL FAVOR A CONSENSUS OF THE OPERATIONAL GFS AND ECMWF SOLUTIONS AS A STARTING POINT FOR THE EXTENDED GRIDS. SENSIBLE WEATHER WILL FEATURE A CONTINUATION OF THE SOUPY AND UNSETTLED CONDITIONS FROM THE SHORT TERM INTO THE DAY TUESDAY. THIS WILL MEAN A THREAT OF CONVECTION AND POSSIBLY EXCESSIVE RAIN FALL. A FRONTAL BOUNDARY WILL START TO MOVE SOUTH THROUGH THE AREA LATER THAT NIGHT AND ON WEDNESDAY AS LOW PRESSURE CONSOLIDATES OVER THE MID ATLANTIC COASTAL STATES. HIGH PRESSURE AND SOMEWHAT DRIER AIR WILL MOVE INTO KENTUCKY ON THURSDAY AND PROVIDE A WELCOMED CHANGE OF AIR MASS AND BREAK FROM THE SHOWER AND THUNDERSTORM THREATS. THIS HIGH WILL MOVE EAST ON FRIDAY AND FRIDAY NIGHT AS A NEW AREA OF LOW PRESSURE TAKES SHAPE OVER THE CENTRAL PLAINS LOOKING TO SLIP INTO KENTUCKY ON SATURDAY. THIS WILL BRING RENEWED CHANCES OF SHOWERS AND THUNDERSTORMS TO EAST KENTUCKY FOR THE WEEKEND...ALONG WITH SOMEWHAT COOLER TEMPS. THE SFC LOW ASSOCIATED WITH THIS LOOKS TO PASS THROUGH ON SUNDAY WITH THE BEST PCPN EXITING LATER IN THE DAY...WHILE THE COOLER AIR REMAINS TO START THE NEW WORK WEEK. THE CR GRID LOAD CAME IN REASONABLE CONSIDERING THE DIFFERENCES IN THE SPECIFICS FROM THE MODELS. DID NUDGE DOWN POPS A BIT FROM THURSDAY INTO FRIDAY NIGHT...MORE TOWARD THE 00Z OPERATIONAL ECMWF. ALSO...ADJUSTED OVERNIGHT LOWS A TAD FOR WEDNESDAY AND THURSDAY NIGHTS TO HIGHLIGHT RIDGE AND VALLEY TEMPERATURE DIFFERENCES. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 200 AM EDT MON JUL 22 2013 CHALLENGING AVIATION FORECAST THIS TIME AROUND...WITH SEVERAL ISSUES TO CONSIDER. FIRST WILL BE THE EXTENT OF FOG AROUND THE FORECAST...AS WE ARE CURRENTLY EXPERIENCING A LULL IN SHOWER AND STORM ACTIVITY. SKIES AT TAF ISSUANCE WERE PARTLY CLOUDY WITH VERY LIGHT WINDS...SO SOME AREAS WILL BE EXPERIENCING FOG OVERNIGHT. JKL WILL BE THE MOST CHALLENGING DUE TO THE ELEVATION OF THE AIRPORT. WILL LIKELY SEE WILD FLUCTUATIONS IN CIGS AND VSBYS AT JKL UNTIL MORE WIDESPREAD SHOWERS AND STORMS MOVE ACROSS THE AREA LATER THIS MORNING. HAVE USED A TEMPO GROUP TO ADDRESS ANY POTENTIAL LIFR CONDITIONS...WITH IFR TO MVFR CONDITIONS OTHERWISE. WENT A BIT MORE OPTIMISTIC WITH LOZ AND SME GOING WITH MOSTLY MVFR CONDITIONS THROUGHOUT THE PERIOD. THE PERIOD FROM 10Z ON WILL FEATURE WIDESPREAD SHOWERS AND STORMS WITH THE POSSIBLILITY OF LOCALLY HEAVY RAINFALL. && .JKL WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH THROUGH THIS EVENING FOR KYZ044-050>052- 058>060-068-069-079-080-083>088-104-106>120. && $$ UPDATE...AR SHORT TERM...KAS LONG TERM...GREIF AVIATION...AR
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
136 AM EDT MON JUL 22 2013 ...Updated Aviation Discussion... .FORECAST UPDATE... Issued at 840 PM EDT Sun Jul 21 2013 Two effective boundaries are forcing convection this evening, as we remain in a juicy environment ahead of an approaching upper impulse. Isolated to scattered storms are firing along and just south of the I-64 corridor, with one particularly vigorous cell that has produced torrential rain and wind gusts near 50 mph in the Louisville Metro. A more solid area of rain with a leading convective line has fired along a northward-moving boundary in western Kentucky, and is trying to spread into south central Kentucky. May continue to see development near Interstate 64 into late evening, especially as outflows interact with each other. Otherwise the storms to our west will spread into the area, with likely POPs looking like a good bet after midnight. Current zone forecast has this handled fairly well, but the point-and-click and matrices have been updated to hone the finer details of when and where it will rain the rest of this evening. && .SHORT TERM (Tonight through Monday Night)... Issued at 300 PM EDT Sun Jul 21 2013 The synoptic pattern this afternoon features a low-amplitude western ridge/eastern trough pattern, placing the Ohio Valley within northwest flow aloft. A rather potent shortwave trough (compared to past weeks) will be the main focus for convection through the short term period. Convection this afternoon has remained across southern Kentucky and Tennessee. In fact, a cold pool finally developed in the convection across southern KY, which raced into Tennessee and has since cut off much of the CWA from any thunderstorm activity. While a few thunderstorms may redevelop across the area yet this afternoon into the evening, think anything will remain rather isolated in the near term. The main focus of the period will come tonight into early Monday morning, as the aforementioned shortwave trough dives into the region. Guidance suggests quite a bit of moisture transport occurring in response to the approaching PV anomaly. A low-level jet, which has been absent as of late, will increase to 20-30 knots. PWATs will rise into the 2-2.25 inch range overnight, which is in the 99th percentile climatologically for this time of year. Additionally, warm cloud depths will rise to near 14,000 feet. Seriously considered going with a flash flood watch, but there are a few mitigating factors. Slightly better tropospheric flow (500mb wind speeds will increase to 20-30 knots) will favor quicker storm motions than we`ve seen of late. Additionally, it`s tough to say which mesoscale boundaries will focus convection, and whether the orientation of any of these boundaries will favor training. Therefore, after coordination with surrounding offices, will hold off on one for now, but will advise the evening shift of the situation. Despite better flow aloft, the highly saturated atmospheric profiles will limit any severe potential due to a lack of instability and dry air aiding in downdraft potential. Therefore, expect the main threats to be torrential rain and lightning. The lead shortwave trough will push through by late Monday morning. How the overnight convection plays out will largely factor into the afternoon prospects for convection as the trough axis slides through. Think that many areas will likely be worked over, so don`t think coverage tomorrow afternoon into the evening will be all that impressive. Nevertheless, as the trough axis swings through, additional convection will likely develop, with the most favored areas being east of Interstate 65. Drier air and subsidence behind the wave should really diminish coverage Monday night. Will carry only chance to slight chance pops, which may still be too generous especially across southern Indiana and northern KY, which have good prospects of staying dry. Temperatures through the short term period will be highly dependent on convection. Therefore, went with a general blend of guidance, which puts lows tonight and tomorrow in the lower 70s, with highs Monday in the middle 80s. .LONG TERM (Tuesday through Sunday)... Issued at 238 PM EDT Sun Jul 21 2013 A cool front will approach from the northwest Tuesday and move through the region Tuesday night. The best mid and upper dynamics will be along and west of the Wabash Valley Tuesday, but we could still see some strong to locally severe storms Tuesday evening west and northwest of Louisville. Also, PWATs are only slightly elevated so widespread heavy rain isn`t expected but locally heavy downpours will certainly be possible. How fast the front moves through and how far it gets south of Kentucky will determine our chances for convection on Wednesday. It does appear that high pressure to our north will wait until Wednesday night to really push in, so will go along with neighboring offices and hold on to a small low confidence PoP on Wednesday, especially south. High pressure from the Great Lakes will be in control for the second half of the work week, keeping us dry. The models have been flaky regarding this weekend`s weather. The general sense, though, is that some sort of storm system will be coming in from the west giving a chance of showers and thunderstorms. We`ll have typical summer temperatures this week with highs in the 80s and lows in the 60s (a little warmer in urban Louisville). && .AVIATION (06Z TAF Update)... Issued at 135 AM EDT Mon Jul 22 2013 Very moist atmosphere remains in place ahead of an upper level disturbance forecast to move through the region this afternoon. Have tried to time storms based on RAP forecasts for now, giving a brief lull to the sites early than more storms. That same moisture likely also will cause brief cig/vsby issues despite storm forecast. Rain chances should become more limited when that trough comes through so have kept in some VFR cigs by mid/late afternoon with no storms. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...NONE. KY...NONE. $$ Update...........RJS Short Term.......KD Long Term........13 Aviation.........RJS
AREA FORECAST DISCUSSION
NWS PADUCAH KY
1233 AM CDT MON JUL 22 2013 .UPDATE... ISSUED AT 1233 AM CDT MON JUL 22 2013 UPDATED AVIATION SECTION ONLY. && UPDATE... ISSUED AT 456 PM CDT SUN JUL 21 2013 AFTER LOOKING AT NEW HRRR MODEL REFLECTIVITY DATA AND 18Z NAM...IT APPEARS HEAVY RAIN IS MORE LIKELY IN SW INDIANA...SE ILLINOIS...AND NW KENTUCKY LATE TONIGHT INTO EARLY MONDAY. 850 MB LOW LEVEL FLOW IS FORECAST TO STRENGTHEN TO AROUND 20 KNOTS...WITH STRONG INDICATIONS OF A BACKBUILDING MCS. RAISED POPS FOR THE OVERNIGHT HOURS TO CATEGORICAL OR LIKELY IN NE COUNTIES. THE ENSEMBLE MEANS OF THE SREF AND GFS ALSO SHOW QPF BULLSEYES IN THAT AREA OVERNIGHT. SURFACE TO 850 MB CONVERGENCE AXIS IS FORECAST TO BE IN THAT AREA WITH A 500 MB SHORTWAVE TROUGH JUST UPSTREAM. && .SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/... ISSUED AT 215 PM CDT SUN JUL 21 2013 MAIN FORECAST CONCERN TONIGHT IS HEAVY RAIN POTENTIAL. LOTS OF MOISTURE AND INSTABILITY IS IN PLACE...ALONG WITH A BROAD AREA OF WEAK LIFT. THE PRIMARY LIFTING MECHANISM IS A 500 MB SHORTWAVE ADVANCING EAST/SOUTHEAST ACROSS CENTRAL MISSOURI. CONVECTION HAS BEEN SLOWLY INCREASING THIS AFTERNOON ALONG AND SOUTH OF A WEAK WARM FRONT THAT EXTENDS FROM THE LOWER OHIO VALLEY TO NORTHWEST ARKANSAS. THE STORMS WILL CONTINUE TO INCREASE THROUGH THE EARLY EVENING HOURS...AIDED BY THE APPROACHING SHORTWAVE AND WARM FRONTAL CONVERGENCE. WILL MENTION HEAVY RAIN IN GRIDS AND ZONES. LOW LEVEL WIND SPEEDS ARE CURRENTLY A LITTLE LOWER THAN OPTIMUM FOR AN ORGANIZED FLOODING THREAT. HOWEVER...RAP MODEL RUNS INDICATE SOME INCREASE AND BACKING OF LOW LEVEL WINDS LATE TODAY AND THIS EVENING. POTENTIAL FOR EXCESSIVE RAINFALL AND LOCAL FLOODING WILL NEED TO BE MONITORED THROUGH EVENING. LATER TONIGHT AND MONDAY MORNING...WEAKENING INSTABILITY AND DECREASING UPPER SUPPORT SHOULD BRING A GRADUAL DECREASE IN COVERAGE AND INTENSITY OF THE PRECIP. TEMPS ON MONDAY WILL DEPEND ON TIMING OF PARTIAL CLEARING...WHICH SHOULD TAKE PLACE FROM WEST TO EAST AS THE DAY GOES ON. WILL CONTINUE WITH PREVIOUS FORECASTS THAT ARE CLOSER TO GFS MOS THAN THE COOLER NAM MOS. A RELATIVE LULL IN PRECIP CHANCES IS EXPECTED MONDAY NIGHT. ON TUESDAY...A COLD FRONT WILL MOVE SOUTHEAST INTO SOUTHERN ILLINOIS AND SE MISSOURI BY LATE IN THE DAY. THE FRONT SHOULD ARRIVE DURING PEAK HEATING AND INSTABILITY...SO WILL CONTINUE WITH POPS ABOVE MOS GUIDANCE. PRECIP WATER VALUES WILL BE SOMEWHAT LOWER DUE TO A MORE VEERED /WEST TO NORTHWEST/ DEEP LAYER FLOW...WHICH IS WHY POPS WILL BE KEPT BELOW THE LIKELY CATEGORY. FLOW FIELDS WILL BE SOMEWHAT STRONGER WITH THIS SYSTEM...SO THE POTENTIAL FOR ISOLATED SEVERE STORMS EXISTS. CONVECTION SHOULD DIMINISH WITH THE PASSAGE OF THE COLD FRONT ACROSS THE LOWER OHIO VALLEY LATE TUESDAY NIGHT. .LONG TERM /WEDNESDAY THROUGH SUNDAY/... ISSUED AT 215 PM CDT SUN JUL 21 2013 THE MODELS ARE IN GENERAL AGREEMENT WITH FRONT ALONG OUR SOUTHERN BORDER BY 12Z WED. HOWEVER THE GFS AND THE NAM PUSH IT ON THROUGH LIMITING ANY PRECIP CHC AFTER 12Z WED. THE 00Z SUNDAY ECMWF LINGERS PRECIP OVER THE AREA ALL DAY WED. CURRENT GRIDS REFLECT HIGHEST PROB WOULD BE OVER SEMO AND LATEST RUNS SUPPORT THAT. HOWEVER WILL TRY TO LOWER POPS NORTH AND EAST AS PREVIOUS SHIFT DID AND CONTINUE THE TREND TOWARD A DRIER WED. IF THE 12Z ECMWF FOLLOWS THAT TREND THE MID SHIFT WILL BE ABLE TO BETTER DEFINE THE CHC. SO THIS TIME FRAME REMAINS A LITTLE SUSPECT FOR NOW WITH EITHER NORTH WINDS VIA NAM GFS OR STALLED FRONT ECMWF. THE 12Z UKMET SHOWS THE FRONT ALONG THE SOUTHERN BORDER AS WELL BUT THE RUN ENDS AT 12Z BUT APPEARS TO FAVOR THE WETTER ECMWF. FOR THE LATE WEEK CHC THE THE GFS BRINGS A FRONT THROUGH BUT THE ECMWF AND DGEX BRING AN MCS OUT OF THE CENTRAL PLAINS FRIDAY WITH A COLD FRONT IN ITS WAKE SATURDAY. THE GFS IS A LITTLE VOID OF THE MCS FEATURE AND WILL LEAN TOWARD THE ECMWF AND DGEX SOLUTION...BUT USE THE SLOWER TIMING OF THE ECMWF FOR THIS FEATURE. WILL MAINTAIN A SLGT CHC SAT NGT IN THE EAST. WILL KEEP SUNDAY DRY WITH MUCH COOLER AND DRIER AIR COMING INTO THE REGION. AS FOR TEMPS IF THE EXTENDED INIT COMES TO FRUITION IT WILL BE A MUCH COOLER AND WE COULD SEE SOME RECORD OR NEAR RECORD COOL TEMPS EARLY NEXT WEEK. THE OPPOSITE OF LAST SUMMER RECORD SETTING HEAT. && .AVIATION... ISSUED AT 1233 AM CDT MON JUL 22 2013 WITH THE EXCEPTION OF SOME SHORT-LIVED IFR CIGS IN SWRN IND...CIGS SHOULD BE VFR/MVFR OUTSIDE OF TSTM ACTIVITY...WHICH IS EXPECTED TO OCCUR AT THE FOUR TAF SITES PRIMARILY BETWEEN ABOUT 06Z IN THE WEST TO AS LATE AS 13Z IN THE EAST AS UPPER LEVEL ENERGY MOVES THROUGH. WINDS WILL BE QUITE VARIABLE OVERNIGHT...BUT SHOULD SETTLE INTO A SWRLY DIRECTION AFTER SUNRISE. EXPECT IMPROVING CONDITIONS AS THE DAY GOES ON. MVFR VSBYS DUE TO FOG/RAIN SHOULD BE COMMON OUTSIDE TSTMS OVERNIGHT. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...NONE. MO...NONE. IN...NONE. KY...NONE. && $$ UPDATE...MY SHORT TERM...MY LONG TERM...KH AVIATION...DB
AREA FORECAST DISCUSSION
NWS CARIBOU ME
648 PM EDT MON JUL 22 2013 .SYNOPSIS... A WARM FRONT WILL APPROACH FROM THE SOUTH TONIGHT. THE FRONT WILL LIFT ONTO THE COAST TUESDAY WHILE A WEAK WAVE OF LOW PRESSURE MOVES ALONG THE FRONT. A COLD FRONT WILL APPROACH TUESDAY NIGHT THEN CROSS THE REGION WEDNESDAY. && .NEAR TERM /THROUGH TUESDAY/... 640 PM UPDATE: MADE SOME MODIFICATIONS TO THE PRECIP CHANCES TO CUT THEM BACK TO SWRN ME USING THE LATEST RUC AND GEM. VISIBLE SATL IMAGERY SHOWED SOME CLOUDS MOVING INTO WESTERN AND DOWNEAST AREAS BUT BREAKING UP AS THEY HIT THE UPPER RIDGE HOLDING IN PLACE. THIS RIDGE IS FCST TO BREAK DOWN AND SHIFT TO THE E OVERNIGHT ALLOWING FOR DEEPER MOISTURE TO STREAM N INTO THE REGION FROM NYS AND PA. TEMPERATURES WERE MODIFIED TO MATCH UP W/THE LATEST TRENDS OF LOW TO MID 70S. TEMPERATURES WILL DROP OFF INTO THE UPPER 60S AND LOWER 70S BY 9 PM. PREVIOUS DISCUSSION... HIGH PRESSURE WILL MOVE AWAY TO THE EAST TONIGHT AS CLOUDS INCREASE AHEAD OF AN APPROACHING WARM FRONT. AS THE WARM FRONT LIFTS NORTH INTO THE GULF OF MAINE TUESDAY MORNING A WEAK WAVE OF LOW PRESSURE TRACKING ALONG THE FRONT WILL CARRY AN AREA OF RAIN INTO THE DOWNEAST REGION. THE LAST FEW RUNS OF THE GFS INDICATE THAT THE RAIN WILL LIFT NORTH TUESDAY MORNING MOVING ACROSS CENTRAL AND EASTERN MAINE AND REACHING NORTHEAST MAINE BY MIDDAY. THE NAM CONFINES SIGNIFICANT RAIN TO DOWNEAST AND EAST CENTRAL AREAS. FOR NOW WILL FORECAST DEFINITE RAIN DOWNEAST AND LIKELY OVER THE NORTH WITH JUST CHANCE IN THE FAR NORTH. THE WARM FRONT STALLS JUST INLAND FROM THE COAST AS THE INITIAL WAVE SLIDES NORTHEAST THROUGH NEW BRUNSWICK LATE TUESDAY. SOME SHOWERS MAY CONTINUE...MAINLY IN DOWNEAST AREAS...AS A SMALL SECONDARY SHORTWAVE MOVING ALONG THE FRONTAL BOUNDARY TRACKS INTO CENTRAL NEW ENGLAND. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/... A DISTURBANCE WILL MOVE ALONG A FRONT ALONG THE DOWNEAST COAST TUESDAY NIGHT...WITH A COLD FRONT APPROACHING NORTHWEST MAINE LATE. AN AREA OF RAIN WILL MOVE ACROSS THE REGION WITH THE DISTURBANCE TUESDAY NIGHT. THIS AREA OF RAIN WILL MOVE EAST OVERNIGHT...WITH PRECIPITATION TAPERING TO SHOWERS LATE. SHOWER CHANCES WILL THEN BEGIN TO INCREASE ACROSS NORTHWESTERN AREAS LATER TUESDAY NIGHT IN ADVANCE OF THE APPROACHING COLD FRONT. SHOWERS AND THUNDERSTORMS WILL CROSS THE REGION IN ADVANCE OF THE COLD FRONT WEDNESDAY...THEN END IN THE WAKE OF THE COLD FRONT THROUGH THE AFTERNOON. HIGH PRESSURE WILL BUILD EAST WEDNESDAY NIGHT THEN CROSS THE REGION THURSDAY THROUGH THURSDAY NIGHT WITH PARTLY CLOUDY/MOSTLY CLEAR SKIES. TEMPERATURES WILL BE AT NEAR NORMAL...TO SLIGHTLY BELOW NORMAL...LEVELS WEDNESDAY THROUGH THURSDAY. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... THE EXTENDED MODELS ARE IN GOOD AGREEMENT THROUGH THE PERIOD. A WEAK HIGH PRESSURE RIDGE WILL BE BUILT OVER THE AREA AT THE START OF THE PERIOD. THERE WILL BE A LOW PRESSURE SYSTEM ALONG THE COAST OF VA...A SECOND LOW PRESSURE SYSTEM OVER LAKE SUPERIOR. FRI EVNG THE LOW ALONG THE COAST OF VA WILL MOVE NORTH. THE GFS AND ECMWF DIFFER ON THE SOLUTION. THE ECMWF BRINGS THE LOW NORTH ALONG THE COAST CENTERED AROUND LONG ISLAND..WITH A WARM FRONT EXTENDING NE INTO THE GULF OF MAINE. THE GFS MOVES THE LOW NORTH BUT KEEPS IT WELL EAST OF THE COAST...AND MAINTAINS THE HIGH PRESSURE RIDGE ACROSS THE AREA. THESE DIFFERENCE CONTINUE INTO SAT MRNG. THE ECMWF MOVES THE LOW NORTH TO BAR HARBOR...EXTENDS THE WARM FRONT EAST INTO NEW BRUNSWICK. THE GFS CONTINUES TO MAINTAIN THE HIGH PRESSURE RIDGE. BOTH MODELS DEEPEN THE LOW OVER LAKE SUPERIOR AND MOVE IT NORTH TO JAMES BAY. BOTH MODELS ALSO SHOW SEVERAL SECONDARY LOWS ALONG A BOUNDARY EXTENDING THROUGH THE GREAT LAKES...THROUGH THE CENTRAL US...TO TEXAS. BY SUN MRNG BOTH MODELS MOVE THE RIDGE EAST OF THE AREA...AS THE FRONT PUSHES INTO VT/NH. BY SUN EVNG THE GFS MOVES THE FRONT INTO WRN MAINE...THE ECMWF INTO NH. MON MRNG THE GFS TO ERN ME...ECMWF WRN ME. MON EVNG THE GFS MOVES THE FRONT THROUGH...THE ECMWF TO ERN ME. BY THE END OF THE PERIOD THE GFS INDICATES THAT MAINE WILL BE INFLUENCED BY WRAP AROUND PRECIP...THE ECMWF MAINTAINS THE LOW OVER MAINE. LOADED MODEL BLEND FOR MAX/MIN TEMP...WND/SKY/POP. ADDED 15 PERCENT TO WINDS FOR GUSTS OVER LAND...20 PERCENT OVER COASTAL WATERS. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... NEAR TERM: VFR CONDITIONS THIS EVENING ARE EXPECTED TO LOWER TO IFR DOWNEAST LATE TONIGHT AND IFR TO MVFR ACROSS THE NORTH TUESDAY MORNING. IFR CONDITIONS IN LOW CLOUDS ARE EXPECTED ON TUESDAY. SHORT TERM: MVFR/IFR...WITH OCCASIONAL LIFR...CONDITIONS ARE EXPECTED ACROSS THE REGION TUESDAY NIGHT INTO WEDNESDAY. CONDITIONS WILL BEGIN TO IMPROVE LATER WEDNESDAY IN THE WAKE OF THE COLD FRONT. GENERALLY VFR CONDITIONS ARE EXPECTED ACROSS THE REGION WEDNESDAY NIGHT THROUGH SATURDAY. && .MARINE... NEAR TERM: WINDS AND SEAS ARE EXPECTED TO REMAIN BELOW SCA THROUGH TUESDAY. HUMID AIR LIFTING NORTH WITH THE WARM FRONT WILL LIKELY RESULT IN SOME FOG OVER THE WATERS LATE TONIGHT INTO TUESDAY. SHORT TERM: SMALL CRAFT ADVISORY LEVEL SEAS ARE POSSIBLE WEDNESDAY INTO WEDNESDAY NIGHT. OTHERWISE...WINDS/SEAS ARE EXPECTED TO BE BELOW SMALL CRAFT ADVISORY LEVELS TUESDAY NIGHT THROUGH THURSDAY NIGHT. VISIBILITIES WILL BE REDUCED IN RAIN AND FOG TUESDAY NIGHT AND WEDNESDAY...WITH A CHANCE OF THUNDERSTORMS WEDNESDAY AFTERNOON. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...NONE. MARINE...NONE. && $$ NEAR TERM...BLOOMER/HEWITT SHORT TERM...NORCROSS LONG TERM...NORTON AVIATION...BLOOMER/HEWITT/NORCROSS MARINE...BLOOMER/HEWITT/NORCROSS
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
907 PM EDT TUE JUL 23 2013 .SYNOPSIS... HIGH PRESSURE BUILDS IN THIS EVENING. A COLD FRONT WILL CROSS THE AREA FROM NORTH TO SOUTH ON WEDNESDAY. HIGH PRESSURE WILL BUILD FOR THE END OF THE WEEK. && .NEAR TERM /THROUGH WEDNESDAY/... A TROUGH OF LOW PRESSURE WILL CONTINUE TO MOVE EASTWARD ACROSS THE GREAT LAKES TONIGHT. DRIER AIR AND HIGH PRESSURE BEHIND A EXITING SHORTWAVE TROUGH HAVE MOVED INTO THE REGION EARLY THIS EVENING. ANOTHER SHORTWAVE TROUGH AHEAD OF AN APPROACHING COLD FRONT WILL MOVE INTO THE REGION BY WED MORNING. AS OF 0030Z...SHOWERS AND THUNDERSTORMS FROM SVR ACTIVITY OVER THE OHIO VALLEY LATE THIS AFTERNOON ARE CROSSING THE ALLEGHENY FRONT. CONDITIONS ACROSS THE MID ATLANTIC WILL CONTINUE TO STABILIZE THIS EVENING AS NOCTURNAL INVERSION STRENGTHENS. DRIER AIR ALOFT PER 00Z IAD RAOB HAS PWAT VALUES OF 1.30. THERE IS STILL INSTABILITY AROUND 1000 J/KG OF CAPE WITH LITTLE SHEAR. SHORTWAVE TROUGH ASSOCIATED WITH SHOWERS AND TSTORMS MOVING INTO THE HIGHLANDS THIS EVENING IS EXPECTED TO WEAKEN TONIGHT. THE LAST FEW MODEL RUNS OF THE HRRR HAS SHOWN ACTIVITY MAKING IT ACROSS THE ALLEGHENY FRONT BUT DIMINISHING BY THE TIME IT GETS TO THE SHENANDOAH VALLEY. AS UPPER LEVEL FORCING DIMINISHES THIS EVENING...OVERNIGHT SHOWER AND THUNDERSTORM THREAT WILL DIMINISH. COLD FRONT WILL MOVE INTO THE REGION BY MORNING AND MOVE ACROSS THE REGION BY WED AFTERNOON. WINDS WILL VEER NORTHERLY BY AFTERNOON. SHOWERS AND ISOLATED THUNDERSTORMS ARE POSSIBLE TOWARDS THE AFTERNOON AHEAD OF COLD FRONT. ALTHOUGH FROPA IS EXPECTED TO MOVE ACROSS THE REGION BY EVENING...NAM AND GFS SHOW A FEW VORT MAXES CROSSING OVER THE FROPA INTO THE EVENING ESPECIALLY ACROSS CHO- PIEDMONT-SOUTHERN MD. CLIMATOLOGICALLY SPEAKING AND WITH 18Z MODEL TRENDS...IN THE MIDDLE OF SUMMER FROPA MAY STALL NEAR OUR SOUTHERN WATERS AND LEAD TO CLOUDY AND WET CONDITIONS INTO THURSDAY FOR THIS AREA. AS FOR SVR THREAT...HEATING AHEAD OF THE FRONT WILL HELP DESTABILIZE COLUMN BUT CLOUD COVER MAY HELP DECREASE THIS. INSTABILITY AND SHEAR ARE MINIMAL TOMORROW BUT SCT THUNDERSTORMS ARE POSSIBLE SOUTH OF I-66 AND I-50 IN MD WITH THE MAIN THREAT FURTHER SOUTH IN SOUTHERN VA. && .SHORT TERM /WEDNESDAY NIGHT/... WL HV CAA/DRY AIR ADVCTN WED NGT. DEWPTS SHUD BE DROPPING INTO THE MID-UPR 50S /!/ OVER A WIDE PORTION OF AREA. HV MADE SIZABLE ADJUSTMENT IN MIN-T AS A RESULT. CONSIDERING THE UNCERTAINTY ON SPECIFICS WED...HV HELD ONTO SCHC POPS SE OF CHO-NAK IN THE EVNG HRS. HWVR...AM ANTICIPATING CLDS ABLE TO SCT OUT...W/ 5-10 KT N/NWLY FLOW PRECLUDING DVLPMNT OF CLDS OR FOG. && .LONG TERM /THURSDAY THROUGH TUESDAY/... WORDS THAT HAVE BEEN SCARCELY USED OVER THE PAST FEW WEEKS - SUCH AS SWEEPING/DRIER/COOLER/STABLE - CAN FINALLY BE USED TO DESCRIBE THE LATTER HALF OF THIS WEEK`S WX. AFTER THE COUPLE OF POTENT UPPER LEVEL VORT SLIDE BY TO OUR NORTH DURING THE EARLY PART OF THE WEEK...WE WILL BE IN THE LARGE-SCALE SUBSIDENCE REGION BEHIND THE EXITING SYSTEMS. HIGH PRESSURE WILL BUILD IN ACROSS THE UPPER MIDWEST AND WE`LL SEE THE STAGNANT HUMIDITY OF THE PAST MONTH SWEPT OFF TO THE EAST. DEWPOINTS IN THE 50S WILL BE PRESENT TO START THE DAY ON THU...ALLOWING FOR ONE OF THE COOLEST NIGHTS SINCE JUNE. THIS COOL START WILL ALSO KEEP THE DAYTIME HIGHS ON THU RELATIVELY COOL AND SEVERAL DEGREES BELOW AVG - BARELY MAKING IT INTO THE L80S. GUIDANCE TRENDS WHICH VARIED ACROSS THE BOARD ARE NOW MORE REASONABLY DEPICTING THE STRENGTH OF THE UPPER WAVE AND ITS PROGRESS. HOWEVER...THE EURO CONTINUES TO SHOW THE SAME DEVELOPMENT OF WEAK CUT-OFF SYSTEM ON THE WARM SIDE OF THE TROUGH AXIS...FURTHER WEST AND JUST ONSHORE. THIS WOULD GIVE THE MID ATLC A CLOUDIER/COOLER AND EVEN WETTER SOLN FOR THU/FRI. THOUGH STILL IN A RELATIVELY CLOSE PROXIMITY TO THE COAST...THE MORE REASONABLE SOLN IS FOR THE PRECIP/CLOUDS IN THE DEPICTION BY THE NAM. THE GFS STILL LIKELY SHOWING SOME BIASES THAT LARGELY WASH OUT THIS FEATURE. THIS OFFSHORE SYSTEM WILL BE THE PRECURSOR TO ANOTHER AND PROBABLY LAST UPPER VORT LOBE TO SWING DOWN FROM THIS UPPER LONGWAVE TROUGH. LONG TERM GUIDANCE DOES MAKE THIS A POTENT AND ANOMALOUSLY COLD UPPER LOW...BUT AGAIN MAINLY SWINGING BY TO THE NORTH. IT WILL BRING SOMEWHAT OF A RETURN OF WARM/HUMID AIR FROM THE SOUTH...NOT NEARLY AS HOT OR MUGGY AS THE PAST COUPLE OF WEEKS - BUT HIGHS IN THE M80S AND U60S DEWPOINTS W/ AN INCREASED CHANCE FOR SHOWERS/TSTMS - ESPC ON SUN. && .AVIATION /01Z WEDNESDAY THROUGH SUNDAY/... VFR CONDITIONS EXPECTED TONIGHT. A COLD FRONT WILL CROSS THE REGION WEDNESDAY AND VCSH IS POSSIBLE AT ALL TERMINALS. CONFIDENCE IS LOW AT THE TIME BUT BEST CHANCE WOULD BE IN THE AFTERNOON AND FOR CHO. N FLOW AOB 10 KNOTS IS EXPECTED BEHIND FROPA. PREVIOUS... DRIER AIR AND CLEARER SKIES TO CLOSE OUT THE WORK WEEK...W/ QUIET CONDITIONS ON THU AND FRI. ANOTHER UPPER LOW WILL SLIDE BY THIS WEEKEND TO OUR NORTH...BRINGING BACK THE WARMER/HUMID AIR FROM THE SOUTH AND INCREASING PRECIP CHANCES. HIGH PRESSURE THEN MOVES IN ON MON/TUE. && .MARINE... ISOLATED SPOTS OF 18KTS HAVE BEEN REPORTED THE PAST HOUR. EXPECT CONDITIONS TO DIMINISH OVERNIGHT AND SCA IS NOT EXPECTED. PREVIOUS...WL HV WLY FLOW ON THE WATERS TNGT...THEN WNDS WL TURN NWLY AS A CDFNT APPROACHES WED. WNDS WL CONT TO VEER NLY WED NGT. SPDS OVERALL SHUD BE AOB 10 KT...THO CUD BE SOME 15 KT GUSTS WED AFTN-EVNG. WL NEED TO MONITOR FOR CHANNELING IN LATER MDL RUNS DURING THIS TIME...DEPENDENT UPON HOW STRONG CDFNT ENDS UP. HIGH PRESSURE OVER THE UPPER MIDWEST WILL DROP WINDS OFF TO LIGHT AND VRB LATE THIS WEEK...THOUGH A WEAK UPPER LOW PRES SYSTEM WILL LIKELY DEVELOP JUST OFF THE MID ATLC COAST THU/FRI. THIS MAY BRING AN ISOLATED SHOWER AND BRIEF PERIODS OF INCREASED SFC WINDS FROM THE PRES GRADIENT INCREASE. SHOWERS AND TSTMS POSSIBLE THIS WEEKEND...THEN HIGH PRES WILL BUILD BACK INTO THE REGION. && .TIDES/COASTAL FLOODING... POSITIVE ANOMALIES LIKELY TO CONTINUE FOR THE NEXT HI TIDE WITH WATER TRAPPED BY W-NW FLOW THROUGH WEDNESDAY. COASTAL FLOODING IS NOT ANTICIPATED AT THIS TIME AS WINDS WILL DIMINISH THIS EVENING. THE NEXT HIGH TIDE WILL BE THE GREATER OF THE TWO AND ANNAPOLIS WILL BE MONITORED OVERNIGHT. THE NEXT HI TIDE FOR ANNAPOLIS 7:06 AM. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...NONE. && $$ SYNOPSIS...HAS NEAR TERM...HAS SHORT TERM...HTS LONG TERM...GMS AVIATION...HAS/GMS MARINE...HAS/GMS TIDES/COASTAL FLOODING...HAS
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
256 AM EDT MON JUL 22 2013 .SYNOPSIS... HIGH PRESSURE REMAINS ANCHORED OFF THE SOUTHEAST COAST DURING THE EARLY PORTION OF THIS WEEK...AS A COLD FRONT BECOMES NEARLY STATIONARY FROM THE OHIO VALLEY TO THE NORTHERN MID ATLANTIC STATES. MEANWHILE...AN UPPER LEVEL TROUGH OF LOW PRESSURE WILL PERSIST ACROSS THE REGION. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... LATEST WX ANALYSIS SHOWS WEAKENING SFC FRONT FROM JUST SOUTH OF LONG ISLAND NY...EXTENDING W-SW BACK INTO THE OHIO AND MIDDLE MISSOURI VALLEYS. BULK OF CONVECTION WHICH ERUPTED ALONG SFC TROUGH...AND DUMPED BETWEEN 3 AND 5 INCHES OVER PARTS OF THE PIEDMONT AND MIDDLE PENINSULA EARLIER THIS EVENING...HAVE GREATLY DIMINISHED IN INTENSITY AND AREAL CVG WITH LOSS OF HEATING AND AS NOCTURNAL STABILITY SETS IN. HRRR HAS HANDLED TRENDS RATHER WELL THIS EVENING AND HV CONTINUED TO LEAN IN ITS DIRECTION OVERNIGHT. OVERALL, WHILE INSTABILITY AND SYNOPTIC SCALE FORCING WANE SIGNIFICANTLY OVERNIGHT, WEAK LLVL CONVERGENCE ALONG THE TROUGH AXIS PERSISTS. THUS, WILL RETAIN A SLIGHT CHC/LOW CHC POP FOR AN ISO TO WIDELY SCT SHRA AFTER MIDNIGHT. ANOTHER WARM AND HUMID OVERNIGHT IS EXPECTED WITH LOWS IN THE LOW/MID 70S...UNDER A PARTLY TO MOSTLY CLOUDY SKY. && .SHORT TERM /6 AM THIS MORNING THROUGH WEDNESDAY/... THE OVERALL PATTERN REMAINS UNSETTLED MONDAY AS A SURFACE BOUNDARY/WEAK LOW STALL OVER THE AREA. ADDITIONALLY...A VIGOROUS TROUGH CARVES OVER THE GREAT LAKES. A LEADING SHORTWAVE EJECTS OUT OF THE TROUGH ACROSS THE OHIO VALLEY TOWARD THE APPALACHIANS MONDAY AFTERNOON/EVENING. HENCE...HIGH CHANCE/LOW-END LIKELY POPS ARE FORECAST MONDAY AFTN/EVENING. AFTERNOON HIGHS WILL TREND DOWN SLIGHTLY DUE TO INCREASED CLOUD COVER AND A HIGHER PROBABILITY OF SHOWERS/TSTMS (AND SHIFTING WIND DIRECTION MAINLY N)...ALTHOUGH DEWPOINTS WILL REMAIN IN THE LOW/MID 70S. HIGHS SHOULD RANGE FROM THE MID/UPPER 80S TO AROUND 90 MONDAY. ANY SEVERE THREAT LOOKS RATHER LIMITED MONDAY...WITH THE MAIN CONCERN AGAIN BEING HEAVY RAIN FROM SLOW MOVING STORMS. THE PARENT TROUGH PIVOTS N OF THE GREAT LAKES TUESDAY AS A SECONDARY WAVE LIFTS ACROSS THE MID ATLANTIC. THE LATEST DATA BRINGS THE WAVE THROUGH EARLIER IN THE DAY...FOLLOWED BY WESTERLY MID-LEVEL FLOW BY LATER AFTERNOON. GIVEN THIS...POPS HAVE BEEN LOWERED...ESPECIALLY W. HOWEVER..A WELL-DEFINED LEE SIDE TROUGH REMAINS OVER THE AREA...SO WILL MAINTAIN 30 POPS W...TO 40 E. HIGHS SHOULD AVERAGE IN THE UPPER 80S TO LOW 90S. THE 21/12Z GFS/NAM BRING YET ANOTHER SHORTWAVE TROUGH THROUGH THE REGION WEDNESDAY. THE MAIN MOISTURE FEED MAY BE WELL OFF THE COAST BY THIS TIME...SO WILL GO NO HIGHER THAN CHANCE POPS AT THIS TIME. HIGHS SHOULD AGAIN RANGE FROM THE UPPER 80S TO LOW 90S. LOWS THROUGH THE PERIOD SHOULD RANGE FROM 70-75. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... UPR TROF OVR THE ERN THIRD OF THE U.S. WED NGT THRU THU...WILL SHIFT EWRD AND OFFSHR THU NGT THRU FRI. THIS WILL PUSH FRNTL BNDRY ALNG OR JUST OFFSHR AT THE BEGINNING OF THE PERIOD...FARTHER OUT TO SEA. WEAK HI PRES WILL BLD INTO AND OVR THE AREA FOR FRI NGT INTO SAT. THEN...ANOTHER SHRTWV TROF AND ASSOCIATED COLD FRONT WILL APPROACH AND MOVE INTO THE REGION LATE SAT NGT THRU SUN. AT THIS TIME...WILL NOT BE GOING ANY HIGHER THAN 20% OR 30% THRU THE PERIOD...DUE TO LOW CONFIDENCE OF COVERAGE. MIN TEMPS WILL BE IN THE UPR 60S TO MID 70S THU MORNG...AND MAINLY IN THE MID 60S TO LWR 70S FRI...SAT AND SUN MORNGS. MAX TEMPS WILL GENERALLY BE IN THE MID TO UPR 80S THRU THE PERIOD. && .AVIATION /07Z MONDAY THROUGH FRIDAY/... LGT AND VRB WNDS THIS MRNG WITH A WEAK TROF OF LO PRES IN THE VICINITY. LO-LVL MOISTURE TRAPPED UNDER A WEAK INVERSION WILL LEAD TO LIFR CONDS OVER RIC FOR AT LEAST THE NEXT 6 HR...WITH MVFR VSBYS FOR SBY...AND VFR ELSEWHERE WHERE TEMP/DEWPT SPREADS ARE LARGER. FOR DAYTIME TDY...AS WITH YESTERDAY EXPECT SCT AFTN/EVENG SHRAS/TSTMS. THUNDER PSBL AS WELL BUT KEPT OUT OF THE TAFS FOR NOW DUE TO UNCERTAINTIES SUCH AS TIMING. VSBY/CIG REDUCTIONS LIKELY IN HEAVIER SHRAS/TSTMS. LO CLDS MAY PERSIST FOLLOWING THE RAIN TNGT ALONGSIDE DIMINISHING WINDS WITH THE FRNTAL BNDRY IN THE VICINITY. OUTLOOK...SCT MAINLY AFTN AND EARLY EVENING TSTMS CAN BE EXPECTED TUE THROUGH FRI. AVIATION CONDS MAY LWR BRIEFLY IN HEAVIER PCPN. PATCHY IFR FOG NEAR SUNRISE CANNOT BE RULED BUT NO WIDESPREAD IFR IS INDICATED. && .MARINE... SUB-SCA CONDS WILL PREVAIL OVER THE NEXT SEVERAL DAYS OVER AREA WATERS. SWELLS WILL IMPACT THE COASTAL WATERS DUE TO STRONGER WINDS ASSOCIATED WITH THE BERMUDA HIGH WELL OFF THE COAST. ADDED SOME HEIGHT TO THE SEAS DUE TO THE SWELL...ESPECIALLY MONDAY NIGHT AND EARLY TUESDAY...BUT KEPT THEM BELOW 5 FT FOR OUR COASTAL ZONES. EXPECT LOCALLY STRONGER WNDS IN SHOWERS AND TSTMS THRU THE PERIOD. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...NONE. && $$ SYNOPSIS...AJZ/LKB NEAR TERM...MAM SHORT TERM...AJZ/LKB LONG TERM...TMG AVIATION...MAS/JEF MARINE...LSA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
709 PM EDT TUE JUL 23 2013 .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 411 PM EDT TUE JUL 23 2013 WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A VIGOROUS SHORTWAVE OVER JAMES BAY. PRES GRADIENT BTWN ITS ASSOCIATED SFC LOW E OF JAMES BAY AND SFC HIGH PRES OVER NW MN/ERN DAKOTAS HAS RESULTED IN BREEZY N/NW WINDS TODAY AND MUCH COOLER CONDITIONS COMPARED TO YESTERDAY. PER WATER VAPOR IMAGERY...IN THE NW FLOW UPSTREAM...THERE ARE A COUPLE OF SHORTWAVES EVIDENT...ONE OVER ERN MT/WRN ND AND ANOTHER OVER CNTRL SASKATCHEWAN. THE NRN WAVE MAY BE A FACTOR IN THE WEATHER HERE ON WED. A QUIET...COOL NIGHT IS IN STORE TONIGHT AS SFC HIGH PRES SETTLES SE INTO WI...BRINGING DIMINISHING WINDS FROM W TO E. WITH DECREASING WINDS...CLEAR SKIES AND PRECIPITABLE WATER 50-70PCT OF NORMAL... EXPECT A DECENT RADIATIONAL COOLING NIGHT...ESPECIALLY OVER W AND SW UPPER MI AS WINDS SHOULD DIMINISH TO CALM IN THAT AREA...BEING CLOSER TO SFC HIGH PRES CENTER. WILL CONTINUE TO SHOW LOWEST TEMPS IN THAT AREA (40 TO THE LWR 40S). OTHERWISE...MIN TEMPS SHOULD BE IN THE 40S IN THE INTERIOR TO MOSTLY AROUND 50F ALONG THE GREAT LAKES. AFTER A QUIET NIGHT...ATTENTION ON WED SHIFTS TO POSSIBLE AFTN CONVECTION. SUMMERTIME WNW/NW FLOW IS OFTEN A FAVORABLE PATTERN FOR ISOLD/SCT AFTN CONVECTION AS EVEN THE MOST SUBTLE SHORTWAVES CAN SPARK SOME PCPN. IF THERE WASN`T A SHORTWAVE PRESENT UPSTREAM... WOULD HAVE DROPPED PCPN MENTION ON WED...BUT SINCE THERE IS AN OBVIOUS WAVE CURRENTLY UPSTREAM IN CNTRL SASKATCHEWAN...IT LOOKS LIKE THERE WILL PROBABLY BE SOME ISOLD AFTN CONVECTION AS THE WAVE DROPS SE INTO THE AREA. WILL CONTINUE TO HIGHLIGHT SCHC POPS OVER MAINLY THE INTERIOR W AND CNTRL WHERE THE LIMITED INSTABILITY IS BEST. NAM/GFS MLCAPES ARE ONLY AS HIGH AS 200-300J/KG DURING THE MID AFTN...SO THUNDER POTENTIAL APPEARS MINIMAL. HOWEVER...CANADIAN RADARS CURRENTLY SHOW DECENT RETURNS IN THE VCNTY OF SHORTWAVE IN SASKATCHEWAN AND SATELLITE IMAGERY SUGGESTS SOME DECENT CONVECTION...SO THERE MAY BE SOME THUNDER OCCURRING WITH THE WAVE THIS AFTN. FOR NOW...WILL LEAVE THUNDER MENTION IN THE FCST FOR WED AND LET LATER SHIFTS REASSESS. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 411 PM EDT TUE JUL 23 2013 MUCH OF THE LONG TERM PERIOD WILL BE INFLUENCED BY A SHORTWAVE DROPPING SOUTH-SOUTHEAST THROUGH CENTRAL CANADA ON WEDNESDAY AND WEDNESDAY NIGHT...WHICH THEN MOVES INTO CENTRAL ONTARIO BY THURSDAY NIGHT AND CLOSES OFF. THIS UPPER LOW WILL REMAIN IN CENTRAL ONTARIO INTO SUNDAY BEFORE SHIFTING NORTHEAST INTO ONTARIO FOR THE START OF THE WORK WEEK. WEDNESDAY NIGHT WILL BE RELATIVELY QUIET AS ANY DIURNAL CLOUDS AND SHOWERS DIMINISH FAIRLY QUICKLY DURING THE EVENING. THEN...EXPECT MID-HIGH CLOUDS TO BE ON THE INCREASE THROUGH THE NIGHT AS THE SHORTWAVE MOVES INTO SOUTHWEST ONTARIO AND AN ASSOCIATED 1008MB LOW DEVELOPS EAST OF LAKE WINNIPEG AND SLIDES EAST. AS THE SHORTWAVE AND SURFACE LOW CONTINUE TO THE EAST-SOUTHEAST ON LATE WEDNESDAY NIGHT AND THURSDAY...AN ASSOCIATED COLD FRONT WILL SLIDE INTO WESTERN UPPER MICHIGAN DURING THE AFTERNOON. THAT WILL BE THE AREA WITH THE BEST OPPORTUNITY FOR SHOWERS/THUNDERSTORMS ON THURSDAY AFTERNOON AND WILL CONTINUE TO HIGHLIGHT INCREASING POPS TO LIKELY VALUES DURING THE AFTERNOON. INSTABILITY LOOKS FAIRLY LIMITED OVER MOST OF THE AREA...WITH MLCAPE VALUES AROUND 500 J/KG ALTHOUGH MUCAPE VALUES DO APPROACH 1500 J/KG IN SOME MODELS OVER THE WEST AND 09Z SREF ONLY INDICATES A 20 PERCENT CHANCE 1000 J/KG IS REACHED. CAPE IS FAIRLY TALL/SKINNY AS SEEN IN NCAPE VALUES IN THE 0.05-0.1 RANGE. AS FOR SHEAR...0-6KM AND EFFECTIVE VALUES ARE ALSO MARGINAL (AROUND 30-35KTS)...ALTHOUGH THERE IS SOME LOW LEVEL VEERING TO THE WIND. THE STRENGTH OF THE SHORTWAVE MAY HELP OVERCOME THE MARGINAL INSTABILITY/SHEAR...BUT THINK THE STORMS WILL PRIMARILY BE SUB SEVERE. THEY WILL LIKELY BE THE STRONGEST OVER THE FAR WEST...WHERE IT IS CLOSER TO THE SYNOPTIC AND FRONTAL FORCING. NAM/GFS STORM MOTION VECTORS INDICATE THE STORMS WILL MOVE FAIRLY QUICKLY TO THE EAST (AROUND 40KTS) AND HAVE FOLLOWED SUIT WITH THE POPS. BUT THE OVERALL TREND WITH THE FRONT HAS BEEN SLOWER...WITH IT NOW EXITING EASTERN UPPER MICHIGAN BETWEEN 09Z-18Z FRIDAY. MODELS DIFFER SOMEWHAT WITH THE POSITION OF THE SURFACE/UPPER LOW...BUT THE GENERAL IDEA OF COOL...CYCLONIC FLOW AFFECTING THE UPPER GREAT LAKES FRIDAY THROUGH SUNDAY MORNING SEEMS REASONABLE. ANOTHER SHORTWAVE ROTATES AROUND THE UPPER LOW ON FRIDAY AND PRECIPITATION CHANCES DEPEND ON HOW QUICKLY THE FRONT MOVES EAST...THE DRY SLOT BEHIND IT...AND ADDITIONAL MOISTURE DROPPING SOUTHEAST ACROSS WESTERN LAKE SUPERIOR. THESE FEATURES ARE STILL VARIABLE IN THE MODELS...BUT THE MORNING LOOKS TO HAVE THE BEST OPPORTUNITY FOR LINGERING SHOWERS OVER THE SE U.P. TRIED TO SHOW A LITTLE MORE TIMING ON POPS FOR FRIDAY BUT CONFIDENCE WASN/T HIGH ENOUGH TO SHOW DRY PERIODS UNDER THE DRY SLOT. WITH THE MOISTURE WRAPPING AROUND THE UPPER LOW FRIDAY NIGHT INTO SATURDAY NIGHT...EXPECT THERE TO BE PERIODS OF CLOUDS...ESPECIALLY FRIDAY NIGHT INTO SATURDAY. MOST OF THE MOISTURE IS FAIRLY SHALLOW...BUT THERE MAY BE ENOUGH AROUND FOR SOME LIGHT RAIN SHOWERS/DRIZZLE ON FRIDAY NIGHT INTO SATURDAY AND WILL RETAIN SLIGHT CHANCE POPS. TEMPERATURES THIS WEEKEND WILL VERY COOL FOR LATE JULY STANDARDS...WITH LOW 60S ON SATURDAY (10-15 DEGREES BELOW NORMAL) AND MID-UPPER 60S FOR SUNDAY. THE UPPER LOW SHIFTS AWAY ON SUNDAY AFTERNOON AND THE AREA WILL BE BACK UNDER WEST-NORTHWEST FLOW ALOFT. BOTH GFS/ECMWF ARE SHOWING A SHORTWAVE AND ASSOCIATED WARM FRONT MOVING TOWARDS THE AREA SOMETIME MONDAY TO TUESDAY AND HAVE SLOWLY BROUGHT POPS UP TO CHANCES BY TUESDAY. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING) ISSUED AT 708 PM EDT TUE JUL 23 2013 HIGH PRES BUILDING INTO THE AREA...EXPECT VFR CONDITIONS TO DOMINATE THRU THIS FCST PERIOD AT KIWD/KCMX/KSAW. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 411 PM EDT TUE JUL 23 2013 AFTER A PERIOD OF STRONG WINDS TODAY ACROSS LAKE SUPERIOR IN THE WAKE OF A COLD FRONT...LIGHTER WINDS UNDER 20KT WILL BE THE RULE TONIGHT INTO WED AS HIGH PRES BUILDS INTO THE WRN GREAT LAKES. AS THE HIGH SHIFTS E AND LOW PRES APPROACHES FROM THE NW...WINDS WILL BECOME SOUTHERLY WED NIGHT/THU...BUT REMAIN UNDER 20KT. EVEN AFTER THE LOW PASSES THRU THE UPPER GREAT LAKES/NRN ONTARIO...WINDS WILL PROBABLY REMAIN 20KT OR LESS LATE WEEK AND THRU THE WEEKEND. HOWEVER...WILL NEED TO WATCH FOR STRONGER SOUTHERLY WINDS THU NIGHT JUST AHEAD OF THE LOW AND ASSOCIATED COLD FRONT AND THEN LATER FRI INTO SAT BEHIND COLD FRONT. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... BEACH HAZARDS STATEMENT UNTIL 10 PM EDT THIS EVENING FOR MIZ005- 006. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...ROLFSON LONG TERM...SRF AVIATION...07 MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS GAYLORD MI
142 PM EDT MON JUL 22 2013 .SYNOPSIS... ISSUED AT 407 AM EDT MON JUL 22 2013 HIGH PRESSURE EXITS EAST TODAY WHILE LOW PRESSURE LIFTS THROUGH ONTARIO. THIS WILL DRAG A WARM FRONT AND A FEW SHOWERS ACROSS THE NORTH WOODS. CHANCES FOR SHOWERS AND THUNDERSTORMS THEN DEVELOPS THROUGH THE DAY...OUT AHEAD OF A COLD FRONT WHICH WILL SWEEP ACROSS NORTHERN MICHIGAN TONIGHT...PROVIDING THE BETTER CHANCE FOR SHOWERS AND STORMS. HIGH PRESSURE BUILDS IN AGAIN FOR THE LATTER HALF OF THE WORK WEEK...BRINGING COOLER AND LESS HUMID WEATHER BACK TO NORTHERN MICHIGAN. && .UPDATE... ISSUED AT 1200 PM EDT MON JUL 22 2013 MID MORNING SURFACE ANALYSIS SHOWS 999MB LOW CENTER OVER NORTHWEST ONTARIO JUST NORTH OF THE BOUNDARY WATERS...TRAILING COLD FRONT EXTENDS BACK INTO SOUTHWEST MINNESOTA/EASTERN NEBRASKA WITH A WARM FRONT EXTENDING SOUTHEAST ACROSS CENTRAL UPPER/NORTHWEST LOWER MICHIGAN. MOISTURE HAS BEEN INCREASING ACROSS MICHIGAN OVER THE LAST 24 HOURS...PRECIPITABLE WATER ON 12Z APX SOUNDING HAS DOUBLED SINCE 12Z SUNDAY (1.07 INCHES). STRAIGHT MODIFICATION OF THE SOUNDING MIXING TO 800MB (78/58) ONLY YIELDS AROUND 400J/KG MLCAPE BUT DEW POINTS HAVE BEEN CLIMBING INTO THE LOWER 60S...AND TEMPERATURES ALREADY IN THE MID/UPPER 70S. SO AN 81/63 PARCEL PUSHES MLCAPE VALUES ABOVE 1100J/KG. ALREADY GETTING SOME CU DEVELOPING EAST OF AN LDM-PZQ LINE...AND A FEW RADAR RETURNS POPPING UP ALONG THE THUMB. BASIC FORECAST IDEAS WILL REMAIN INTACT WITH CONVECTION POPPING UP THIS AFTERNOON...WITH 1000-1500J/KG MLCAPE EXPECTED. WILL KEEP NORTHWEST LOWER SHORELINE COUNTIES DRY WITH AN ONSHORE BREEZE/LAKE SHADOW. DEEP LAYER SHEAR NOT STRONG TODAY...SOME DECENT VEERING OF WINDS ALOFT BUT NOT MUCH SPEED SHEAR (0-6KM BULK SHEAR VALUES 20-30KTS). HAVE BEEN ADJUSTING THE TIMING A BIT GIVEN CURRENT TRENDS. FORECAST HIGHS UPPER 70S-MID 80S LOOK FINE. UPDATE ISSUED AT 638 AM EDT MON JUL 22 2013 ONE SHORTWAVE TROUGH WAS EXITING NE LOWER ALONG WITH LIGHT RAIN SHOWERS AND SPRINKLES. A WEDGE OF DRIER AIR IS NOW FILLED IN ACROSS ALL OF NRN MICHIGAN...WITH SUNSHINE GETTING THE DAY STARTED OFF RIGHT. THE WARMING UNDER THE SUN...AND ADVECTION OF HIGHER SFC TDS NORTHWARD WITH LIGHT SOUTHERLY FLOW BEHIND THE WARM FRONT...WILL WORK IN TANDEM FOR CONVECTION TO BREAK OUT WITH THE ASSIST FROM OROGRAPHIC FLOW/TERRAIN INDUCED LIFT. NO CAP SEEN ON FCST SOUNDINGS STILL SUGGEST THAT SHOWERS AND A FEW STORMS COULD POP OFF AS EARLY AS LATE MORNING THROUGH AFTERNOON....MAINLY THE INTERIOR HIGHER TERRAIN AND NE LOWER...AS SOUTHERLY FLOW SHOULD STABILIZE THE BL ACROSS EASTERN UPPER. NO SEVERE STORMS ARE EXPECTED WITH TODAY`S ACTIVITY...BUT STILL WATCHING UPSTREAM NEXT SHORTWAVE AND COLD FRONT...WHICH WILL PROVIDE AT LEAST A LOW END CHANCE FOR A SEVERE STORM OR TWO. && .SHORT TERM...(TODAY THROUGH TONIGHT) ISSUED AT 407 AM EDT MON JUL 22 2013 INTERESTING LITTLE FORECAST OVER THE NEXT 24 HOURS...WITH MAIN CONCERN FOCUSED ON POTENTIAL FOR CONVECTION...SOME OF WHICH MAY POSE A SNEAKY SEVERE THREAT FOR A FEW SPOTS LATER THIS EVENING/TONIGHT. OVERALL UPPER PATTERN CONTINUES TO FEATURE BROAD UPPER TROUGHING ACROSS MUCH OF THE NORTHERN TIER...WITH MEAN NORTHWEST FLOW REGIME ALOFT...AND A RATHER POTENT SHORTWAVE WORKING THROUGH SOUTHERN MANITOBA. THERE IS A MODEST SURFACE LOW ASSOCIATED WITH THIS UPPER FEATURE...WITH ANALYSIS SHOWING A 999MB LOW JUST NORTH OF THE ND/MN BORDER...WITH A TRAILING COLD FRONT CROSSING EASTERN ND/SD AS OF 07Z. CLOSER TO HOME...A LOW LEVEL RIDGE AXIS IS NOW PARKED ACROSS THE NORTHEAST CONUS (BUT STILL TRYING TO INFLUENCE OUR WX LOCALLY)...WHILE A WARM FRONT IS GRADUALLY LIFTING BACK NORTH THROUGH THE LOWER LAKES. SAW A DECENT AMOUNT OF CONVECTION JUST NORTH OF THIS FEATURE OVER THE PAST 12 HOURS...HELPED ALONG BY A SECONDARY WEAKER SHORTWAVE TRAVERSING SOUTHERN WISCONSIN...AND WORKING IN TANDEM WITH GOBS MORE MOISTURE (DEW POINTS WELL INTO THE LOWER 70S) AS OPPOSED TO THE DRY AIRMASS THAT`S IN PLACE UP IN OUR NECK OF THE WOODS. WITH THAT SAID...RADAR HAS CONTINUED TO SHOW OCCASIONAL MAINLY LIGHT SHOWERS PERCOLATING ACROSS THE CWA...IN RESPONSE TO A STRONGER PUSH OF 925-800MB THETA-E ADVECTION UNDERWAY ON THE HEELS OF A MODEST LOW LEVEL JET FEATURE RIDING UP THE SPINE OF LAKE MICHIGAN. CONVECTIVE CHANCES THROUGH THE FORECAST PERIOD LOOK TO COME DURING A FEW PERIODS. THE FIRST IS THROUGH AND JUST BEYOND SUNRISE AS LOWER LEVEL THETA-E RIDGE AXIS CONTINUES TO ADVANCE INTO THE REGION...WITH LATEST RAP GUIDANCE SUGGESTING THE NOSE OF BUILDING WEAKISH INSTABILITY (MUCAPES NO BETTER THAN 150J/KG) APPROACHING WHITEFISH BAY BY 12Z. WHILE THE DOWNSTAIRS AIRMASS WILL REMAIN DRY NORTH OF THE SURFACE WARM FRONT...COULD THEORETICALLY CONTINUE TO SEE SOME POPUP SHOWERS JUST ABOUT ANYWHERE ACROSS THE REGION...BUT PROBABLY MOST PRONOUNCED NORTH OF THE BRIDGE. CLOUD COVER IS A BIG ISSUE AS WELL...AS SAID MOISTURE ADVECTION IS DRIVING A THICKER BAND OF CLOUDS NORTH OF M-32...THOUGH WITH THESE LIFTING NORTH WITH TIME. A SECONDARY AXIS OF MID CLOUDS IS DEVELOPING OVER THE LOWER LAKES/SOUTHERN WISCONSIN...AND MAY SEE THIS SLIP ACROSS THE REGION THROUGH MID MORNING. SUSPECT WE SHOULD SEE SOME SUNSHINE BREAK OUT NO LATER THAN LATE MORNING AS THE ELEVATED WARM FRONT MIXES NORTHWARD AND STRONGER THERMAL RIDGING POKES INTO NORTHERN MICHIGAN. THAT SETUP WILL LEAD US TO OUR SECOND CONVECTIVE CHANCE FOR THE DAY AS BETTER BOUNDARY LAYER MOISTURE SPILLS NORTHWARD...WITH DEW POINTS RISING THROUGH THE 60S. FORCING FOR ASCENT IS NOTHING TERRIBLY IMPRESSIVE FOR THE AFTERNOON...AND STRENGTHENING SYNOPTIC FLOW WILL PREVENT ANY LAKE BREEZE DEVELOPMENT. HOWEVER...CONTINUED WARM ADVECTION BELOW 800MB AND MOISTURE ADVECTION COMBINED WITH THE LIKELIHOOD FOR SOME TERRAIN-INDUCED FORCING IN MEAN SOUTHWEST FLOW SHOULD BE ENOUGH TO POP OFF ADDITIONAL ACTIVITY...MAINLY AFTER 17Z. INSTABILITY IS NOTHING HUGE...BUT AN 80/63 PARCEL SHOULD EASILY GIVE UP TO 1000 J/KG LATER TODAY PER CONSENSUS FORECAST RAOBS. BEST CHANCE FOR CONVECTION GIVEN THE SETUP SHOULD BE MAINLY ACROSS CENTRAL AND EASTERN HALF OF THE CWA...AS A LAKE MICHIGAN SHADOW WILL LIKELY BE PRESENT CLOSER TO THE COAST. SEVERE WEATHER THREAT DOESN`T LOOK OVERLY HIGH AS MID LEVEL (850-500MB) LAPSE RATES ARE RATHER PALTRY AND EFFECTIVE SHEAR VALUES ONLY PUSH ABOUT 25 KNOTS AT BEST...COURTESY OF A RATHER LAX FLOW REGIME ABOVE 400MB. HIGHS TODAY WILL BE WARMER...GENERALLY WARMING THROUGH THE LOWER 80S IN MANY AREAS. THE BETTER CHANCE FOR CONVECTION (SUCH AS IT IS) SHOULD ARRIVE LATE THIS EVENING AND TONIGHT AS THE STRONGER UPPER WAVE CROSSES SOUTHERN ONTARIO...DRIVING THE SURFACE FRONT THROUGH THE CWA ROUGHLY 06-12Z. BETTER MID LEVEL LAPSE RATE AXIS FOLDING INTO THE AREA SHOULD GIVE A LITTLE BOOST TO INSTABILITY...WITH MUCAPE VALUES CLIMBING TOWARD 1500 J/KG...MAINLY NORTHWEST HALF OF THE CWA THROUGH 06Z. AT THE SAME TIME...MORE PRONOUNCED MID LEVEL JET IS PROGGED TO ARRIVE JUST AHEAD OF THE BOUNDARY...SUPPORTING THE NOTION OF INCREASING EFFECTIVE SHEAR UP TOWARD 35-40 KNOTS. SHEAR VECTORS NEARLY PARALLEL TO THE LOW LEVEL FRONT CONTINUE TO SUGGEST A LINEAR STRUCTURE TO ANY CONVECTION...AND NOT OUT OF THE QUESTION STRONGER STORMS THAT FIRE OFF ACROSS NORTHERN WISCONSIN/CENTRAL U.P. WILL POSE A WIND (AND MAYBE MARGINAL HAIL) THREAT THROUGH LATE EVENING. CERTAINLY SOMETHING TO WATCH. OTHERWISE...A MILD START TO THE NIGHT AHEAD OF THE FRONT...WITH READINGS LIKELY STUCK IN THE UPPER 60S OR EVEN 70S THROUGH 06-09Z...BEFORE FALLING QUICKLY NORTHERN AREAS BEHIND THE BOUNDARY. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 407 AM EDT MON JUL 22 2013 THE VIGOROUS UPPER LEVEL SHORTWAVE EXITS INTO QUEBEC TUESDAY...WITH NW FLOW ALOFT PERSISTING OVER THE REGION. THE NEXT WAVE IS SET FOR THURSDAY NIGHT...WITH ADDITIONAL SHORTWAVE ENERGY EXPECTED TO ROLL THROUGH INTO THE WEEKEND. BY EARLY NEXT WORK WEEK...WE WILL STILL BE IN NW FLOW ALOFT...BUT WITH UPPER RIDGING STARTING TO WORK INTO THE CENTRAL PART OF THE COUNTRY. THIS UPPER RIDGING LOOKING TO ARRIVE IN THE GREAT LAKES BY THE MIDDLE PART OF THE NEXT WORK WEEK. TUESDAY THROUGH THURSDAY...THE SYSTEM COLD FRONT FROM A POTENT UPPER LEVEL SHORTWAVE WILL BE QUICKLY EXITING NE LOWER TUESDAY MORNING. THERE COULD STILL BE SOME LINGERING SHOWERS AND STORMS IN THE MORNING...BEFORE STRONG DRYING AND CAPPING DEVELOPS OVERHEAD. TEMPERATURES WILL BE COOLING OFF INTO THE DAY...BUT A SECONDARY COLD FRONT/SHOT OF COOLER AIR WORKS IN TO NORTHERN MICHIGAN LATE IN THE AFTERNOON AND OVERNIGHT. NW WINDS BECOME RATHER GUSTY THROUGH THE DAY...REACHING UP TO 30 MPH IN THE AFTERNOON. WINDS WILL SUBSIDE INTO THE NIGHT...BUT WILL NOT REALLY CALM DOWN UNTIL WEDNESDAY AND WEDNESDAY NIGHT AS HIGH PRESSURE SETTLES IN OVERHEAD. ON THURSDAY...THE NEXT SHORTWAVE WILL BE DROPPING INTO ONTARIO LATE IN THE DAY...WHILE THE ASSOCIATED LOW PRESSURE DIVES INTO LAKE SUPERIOR...AND THE COLD FRONT PUSHES THROUGH NW WISCONSIN. THURSDAY NIGHT THROUGH THE WEEKEND...THE WAA AHEAD OF THE AFOREMENTIONED SHORTWAVE/LOW PRESSURE IS RATHER UNIMPRESSIVE. TOTAL THETA-E ADVECTION AT THIS POINT...IS APPEARING LESS AGGRESSIVE THAN WITH WHAT IS EXPECTED WITH TODAY/TONIGHT`S FRONT. REGARDLESS...HEIGHT FALLS...INCREASING INSTABILITY AND FORCING WILL RESULT IN INCREASING CHANCES FOR SEEING SHOWERS AND THUNDERSTORMS THROUGH FRIDAY. THE EXACT TIMING AND SOUTHWARD EXTENT OF THE FRONT IS UNCERTAIN...BUT THE CONSENSUS HERE IS FOR THE FRONT TO SHALLOW OUT AND SLIP INTO FAR SOUTHERN LOWER BY FRIDAY NIGHT. AT THE SAME TIME...A MID LEVEL JET AND RIGHT ENTRANCE REGION OF THE UPPER JET EXITS BY LATE FRIDAY NIGHT/SATURDAY MORNING. DO BELIEVE THAT BASED ON THE PATTERN SEEN IN THE UPPER LEVELS...THAT WE WOULD SEE A RATHER QUIET PERIOD OF WEATHER INTO THE WEEKEND. THE ADDITIONAL ENERGY (TRACK...BASED ON MODEL CONSENSUS) IN THE NOW DEEP CLOSED LOW ALOFT...WORKS ON THE FRONTAL ZONE THAT IS TO OUR SOUTH PUTTING RENEWED CONVECTION SOUTH OF US. WILL JUST KEEP SMALLISH CHANCES FOR ADDITIONAL SHOWERS AND STORMS IN FOR SATURDAY...WHILE WE APPEAR TO GET ENTRENCHED IN DEEPER LOWER THETA-E AIR. TEMPERATURES IN THE MIDDLE AND UPPER 70S...WILL FALL INTO THE UPPER 60S AND LOWER 70S FOR THE UPCOMING WEEKEND. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 140 PM EDT MON JUL 22 2013 COUPLE PERIODS OF SHOWERS/THUNDERSTORMS POSSIBLE AHEAD OF A COLD FRONT TO CROSS NORTHERN MICHIGAN OVERNIGHT. WINDS SHIFT TO THE NORTHWEST BEHIND THE FRONT AND PERHAPS A PERIOD OF HIGH END IFR CEILINGS EARLY TUESDAY MORNING. && .MARINE... ISSUED AT 407 AM EDT MON JUL 22 2013 LIGHTER SOUTHEAST WINDS THROUGH EARLY MORNING WILL SHIFT SOUTHWEST AND STRENGTHEN THROUGH THE DAY...OUT AHEAD OF A COLD FRONT SLIDING THROUGH THE UPPER MIDWEST. WIND SPEEDS MAY WELL REACH SMALL CRAFT ADVISORY LEVELS...PARTICULARLY ON LAKE MICHIGAN SOUTH OF GRAND TRAVERSE LIGHT WHERE COASTAL CONVERGENCE SHOULD HELP BOOST SPEEDS. THOSE STRONGER WINDS OF GENERALLY 10-20 KNOTS WILL CONTINUE THROUGH THE FIRST HALF OF THE NIGHT...BUT SHIFT NORTHWESTERLY WITH TIME AS THE FRONT BLOWS THROUGH. DO EXPECT TO SEE AT LEAST A BROKEN LINE OF SHOWERS AND STORMS ACCOMPANY THE FRONT...WHICH OF COURSE COULD PROVIDE SOME LOCALLY HIGHER WINDS/WAVES. THE FRONT WILL EXIT THE WATERS BY TUESDAY MORNING...WITH GUSTY NORTHERLY WINDS TAKING HOLD...AND ADDITIONAL SMALL CRAFT ADVISORIES LIKELY TO BE NEEDED. HIGH PRESSURE WILL WORK ITS WAY ACROSS THE WATERS INTO MIDWEEK... GIVING A RETURN TO LIGHT WINDS AND LOW WAVES TUESDAY NIGHT THROUGH THURSDAY. && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LH...NONE. LM...NONE. LS...NONE. && $$ UPDATE...JPB SYNOPSIS...SD SHORT TERM...DL LONG TERM...SD MARINE...DL
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
134 PM EDT MON JUL 22 2013 LATEST UPDATE... AVIATION .SYNOPSIS... ISSUED AT 330 AM EDT MON JUL 22 2013 A WARM FRONT WILL BRING A FEW SHOWERS AND THUNDERSTORMS LATER TODAY AND THEN A COLD FRONT WILL BRING MORE SCATTERED SHOWERS AND STORMS TONIGHT INTO TUESDAY. FAIR AND COOLER WEATHER WILL ARRIVE BY LATE TUESDAY AND LAST THROUGH THURSDAY. TEMPERATURES WILL AVERAGE NEAR NORMAL LATE IN THE WEEK THROUGH NEXT WEEKEND. && .UPDATE... ISSUED AT 1110 AM EDT MON JUL 22 2013 DROPPED MAXIMUM TEMPERATURES TODAY SLIGHTLY MAINLY SOUTH OF I-96 TO ACCOUNT FOR THE COOLING EFFECTS OF EXTENSIVE PRECIPITATION OVERNIGHT AND RESIDUAL CLOUD COVER. ALSO RAISED PRECIPITATION CHANCES EAST OF US-131 BASED ON HRRR MODEL GUIDANCE AND TO BETTER AGREE WITH SURROUNDING OFFICES. MAIN FORECAST CONCERN THIS AFTERNOON WILL BE PRECIPITATION CHANCES OVERNIGHT WITH THE APPROACHING COLD FRONT. UPDATE ISSUED AT 537 AM EDT MON JUL 22 2013 A COUPLE OF SHOWERS DEVELOPED IN THE PAST HR...ESPECIALLY NEAR LWA. WENT AND ADDED A RISK FOR A FEW EARLY MORNING SHOWERS PRIMARILY SOUTH OF A BIV TO LAN LINE. && .SHORT TERM...(TODAY THROUGH WEDNESDAY AFTERNOON) ISSUED AT 330 AM EDT MON JUL 22 2013 AFTER SOME LINGERING EARLY MORNING SHOWERS OVER OUR SE FCST AREA DRY WX IS ANTICIPATED FOR THE REST OF THE MORNING IN THE WAKE OF THE DEPARTING MCV THAT BROUGHT THE ROUND OF RAIN AND STORMS YESTERDAY EVENING AND OVERNIGHT. SOME WAA SHOWERS AND A FEW STORMS WILL DEVELOP THIS AFTERNOON. A FAIR AMOUNT OF SUN AND SSW WINDS WILL HELP TO BOOST MAX TEMPS INTO THE LOWER TO MIDDLE 80S ACROSS MOST OF OUR AREA TODAY. THE COLD FRONT WILL MOVE IN FROM THE NW TONIGHT AND BRING SCATTERED SHOWERS AND STORMS WHICH WILL LAST THROUGH ABOUT MIDDAY TUESDAY BEFORE THE FRONT CLEARS OUR AREA. A COOLER AND DRIER AIR MASS WILL ADVECT IN BEHIND THAT FRONT AND MAX TEMPS WEDNESDAY WILL ONLY REACH THE 70S. .LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY) ISSUED AT 330 AM EDT MON JUL 22 2013 PATTERN IS LOOKING COOLER WITH TIME ESPECIALLY THIS WEEKEND. MODELS IN DECENT AGREEMENT IN SHOWING A COLD FRONT PUSHING THROUGH FRI NIGHT INTO SAT WITH A WAVE OF LOW PRESSURE FORMING ON IT OVER SOUTHERN LOWER MI. THIS SHOULD LEAD TO SHOWERS AND WITH INSTABILITY AROUND THUNDERSTORMS. IF THE NEW HIGH RES EURO IS CORRECT SAT COULD BE A RATHER WET DAY FOR THE AREA. NORTHERLY FLOW SETS UP BEHIND THE WAVE LEADING TO STRONG COLD AIR ADVECTION. 925 MB TEMPS FALL TO UNDER 10 DEG C 12Z SUN. IF THIS HAPPENS AND THE UPPER LOW DEVELOPS NORTH OF SUPERIOR AS SHOWN BY THE HIGH RES EURO ON SUN...LAKE ENHANCED MOISTURE MAY IMPACT THE FORECAST. I LOWERED TEMPERATURES OVER GUIDANCE FOR SAT NIGHT THROUGH SUN BASED ON THIS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 134 PM EDT MON JUL 22 2013 THERE ARE A COUPLE OF PERIODS OF NOTE IN THE 18Z FCST PACKAGE. FIRST OF ALL...WE ARE SEEING FAIRLY GOOD CUMULUS DEVELOPMENT EARLY THIS AFTERNOON WITH PLENTY OF INSTABILITY PRESENT. THIS HAS INITIALLY DEVELOPED AS MVFR...BUT SHOULD LIFT TO VFR FAIRLY QUICK. SOME CONVERGENCE PRESENT THIS AFTERNOON COULD HELP POP A FEW SHOWERS AND/OR STORMS THROUGH EARLY EVENING. THE CHCS OF THESE HITTING A TERMINAL ARE NOT VERY HIGH...SO WE HAVE USED A VCSH TO COVER THIS FOR NOW. SOME BRIEFLY LOWER CONDITIONS TO MVFR WILL BE POSSIBLE UNDER ANY SHOWER/STORM. ANOTHER THREAT OF SHOWERS AND/OR STORMS WILL BE POSSIBLE AFTER ABOUT 06Z AT KMKG AND THEN SPREAD TO THE SE OVERNIGHT AHEAD OF A COLD FRONT. WE ARE NOT ENTIRELY SURE EVERYONE WILL SEE RAIN FROM THIS AS PCPN LOOKS TO BE DIMINISHING WITH THE FRONT DUE TO THE LOSS OF DIURNAL INSTABILITY. THIS WARRANTS A VCSH ALSO...AND WE CAN FINE TUNE THIS AS TRENDS REVEAL THEMSELVES BETTER. WINDS WILL SHIFT TO THE NW AFTER THE FRONT PASSES TUE MORNING. A MVFR CLOUD DECK SHOULD MOVE IN BEHIND THE FRONT FOR A FEW HOURS TUE MORNING BEFORE IT LIFTS TUE AFTERNOON. && .MARINE... ISSUED AT 1110 AM EDT MON JUL 22 2013 LATEST OMR SHOWS WAVE HEIGHTS GENERALLY BELOW 2 FEET...ALTHOUGH 3 FEET WAS REPORTED AT GRAND HAVEN. AS NOTED IN THE PREVIOUS DISCUSSION...WINDS AND WAVES WILL INCREASE TODAY. ALTHOUGH A SMALL CRAFT ADVISORY IS NOT ANTICIPATED...WE WILL HAVE TO WATCH THE BEACH HAZARD POTENTIAL /PRIMARILY INCREASING LONG SHORE CURRENTS/ AS IT EVOLVES THIS AFTERNOON AND EVENING. && .HYDROLOGY... ISSUED AT 330 AM EDT MON JUL 22 2013 NO HYDRO ISSUES. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. && $$ UPDATE...TJT SYNOPSIS...LAURENS SHORT TERM...LAURENS LONG TERM...MJS AVIATION...NJJ HYDROLOGY...LAURENS MARINE...TJT
AREA FORECAST DISCUSSION
NWS GAYLORD MI
1200 PM EDT MON JUL 22 2013 .SYNOPSIS... ISSUED AT 407 AM EDT MON JUL 22 2013 HIGH PRESSURE EXITS EAST TODAY WHILE LOW PRESSURE LIFTS THROUGH ONTARIO. THIS WILL DRAG A WARM FRONT AND A FEW SHOWERS ACROSS THE NORTH WOODS. CHANCES FOR SHOWERS AND THUNDERSTORMS THEN DEVELOPS THROUGH THE DAY...OUT AHEAD OF A COLD FRONT WHICH WILL SWEEP ACROSS NORTHERN MICHIGAN TONIGHT...PROVIDING THE BETTER CHANCE FOR SHOWERS AND STORMS. HIGH PRESSURE BUILDS IN AGAIN FOR THE LATTER HALF OF THE WORK WEEK...BRINGING COOLER AND LESS HUMID WEATHER BACK TO NORTHERN MICHIGAN. && .UPDATE... ISSUED AT 1200 PM EDT MON JUL 22 2013 MID MORNING SURFACE ANALYSIS SHOWS 999MB LOW CENTER OVER NORTHWEST ONTARIO JUST NORTH OF THE BOUNDARY WATERS...TRAILING COLD FRONT EXTENDS BACK INTO SOUTHWEST MINNESOTA/EASTERN NEBRASKA WITH A WARM FRONT EXTENDING SOUTHEAST ACROSS CENTRAL UPPER/NORTHWEST LOWER MICHIGAN. MOISTURE HAS BEEN INCREASING ACROSS MICHIGAN OVER THE LAST 24 HOURS...PRECIPITABLE WATER ON 12Z APX SOUNDING HAS DOUBLED SINCE 12Z SUNDAY (1.07 INCHES). STRAIGHT MODIFICATION OF THE SOUNDING MIXING TO 800MB (78/58) ONLY YIELDS AROUND 400J/KG MLCAPE BUT DEW POINTS HAVE BEEN CLIMBING INTO THE LOWER 60S...AND TEMPERATURES ALREADY IN THE MID/UPPER 70S. SO AN 81/63 PARCEL PUSHES MLCAPE VALUES ABOVE 1100J/KG. ALREADY GETTING SOME CU DEVELOPING EAST OF AN LDM-PZQ LINE...AND A FEW RADAR RETURNS POPPING UP ALONG THE THUMB. BASIC FORECAST IDEAS WILL REMAIN INTACT WITH CONVECTION POPPING UP THIS AFTERNOON...WITH 1000-1500J/KG MLCAPE EXPECTED. WILL KEEP NORTHWEST LOWER SHORELINE COUNTIES DRY WITH AN ONSHORE BREEZE/LAKE SHADOW. DEEP LAYER SHEAR NOT STRONG TODAY...SOME DECENT VEERING OF WINDS ALOFT BUT NOT MUCH SPEED SHEAR (0-6KM BULK SHEAR VALUES 20-30KTS). HAVE BEEN ADJUSTING THE TIMING A BIT GIVEN CURRENT TRENDS. FORECAST HIGHS UPPER 70S-MID 80S LOOK FINE. UPDATE ISSUED AT 638 AM EDT MON JUL 22 2013 ONE SHORTWAVE TROUGH WAS EXITING NE LOWER ALONG WITH LIGHT RAIN SHOWERS AND SPRINKLES. A WEDGE OF DRIER AIR IS NOW FILLED IN ACROSS ALL OF NRN MICHIGAN...WITH SUNSHINE GETTING THE DAY STARTED OFF RIGHT. THE WARMING UNDER THE SUN...AND ADVECTION OF HIGHER SFC TDS NORTHWARD WITH LIGHT SOUTHERLY FLOW BEHIND THE WARM FRONT...WILL WORK IN TANDEM FOR CONVECTION TO BREAK OUT WITH THE ASSIST FROM OROGRAPHIC FLOW/TERRAIN INDUCED LIFT. NO CAP SEEN ON FCST SOUNDINGS STILL SUGGEST THAT SHOWERS AND A FEW STORMS COULD POP OFF AS EARLY AS LATE MORNING THROUGH AFTERNOON....MAINLY THE INTERIOR HIGHER TERRAIN AND NE LOWER...AS SOUTHERLY FLOW SHOULD STABILIZE THE BL ACROSS EASTERN UPPER. NO SEVERE STORMS ARE EXPECTED WITH TODAY`S ACTIVITY...BUT STILL WATCHING UPSTREAM NEXT SHORTWAVE AND COLD FRONT...WHICH WILL PROVIDE AT LEAST A LOW END CHANCE FOR A SEVERE STORM OR TWO. && .SHORT TERM...(TODAY THROUGH TONIGHT) ISSUED AT 407 AM EDT MON JUL 22 2013 INTERESTING LITTLE FORECAST OVER THE NEXT 24 HOURS...WITH MAIN CONCERN FOCUSED ON POTENTIAL FOR CONVECTION...SOME OF WHICH MAY POSE A SNEAKY SEVERE THREAT FOR A FEW SPOTS LATER THIS EVENING/TONIGHT. OVERALL UPPER PATTERN CONTINUES TO FEATURE BROAD UPPER TROUGHING ACROSS MUCH OF THE NORTHERN TIER...WITH MEAN NORTHWEST FLOW REGIME ALOFT...AND A RATHER POTENT SHORTWAVE WORKING THROUGH SOUTHERN MANITOBA. THERE IS A MODEST SURFACE LOW ASSOCIATED WITH THIS UPPER FEATURE...WITH ANALYSIS SHOWING A 999MB LOW JUST NORTH OF THE ND/MN BORDER...WITH A TRAILING COLD FRONT CROSSING EASTERN ND/SD AS OF 07Z. CLOSER TO HOME...A LOW LEVEL RIDGE AXIS IS NOW PARKED ACROSS THE NORTHEAST CONUS (BUT STILL TRYING TO INFLUENCE OUR WX LOCALLY)...WHILE A WARM FRONT IS GRADUALLY LIFTING BACK NORTH THROUGH THE LOWER LAKES. SAW A DECENT AMOUNT OF CONVECTION JUST NORTH OF THIS FEATURE OVER THE PAST 12 HOURS...HELPED ALONG BY A SECONDARY WEAKER SHORTWAVE TRAVERSING SOUTHERN WISCONSIN...AND WORKING IN TANDEM WITH GOBS MORE MOISTURE (DEW POINTS WELL INTO THE LOWER 70S) AS OPPOSED TO THE DRY AIRMASS THAT`S IN PLACE UP IN OUR NECK OF THE WOODS. WITH THAT SAID...RADAR HAS CONTINUED TO SHOW OCCASIONAL MAINLY LIGHT SHOWERS PERCOLATING ACROSS THE CWA...IN RESPONSE TO A STRONGER PUSH OF 925-800MB THETA-E ADVECTION UNDERWAY ON THE HEELS OF A MODEST LOW LEVEL JET FEATURE RIDING UP THE SPINE OF LAKE MICHIGAN. CONVECTIVE CHANCES THROUGH THE FORECAST PERIOD LOOK TO COME DURING A FEW PERIODS. THE FIRST IS THROUGH AND JUST BEYOND SUNRISE AS LOWER LEVEL THETA-E RIDGE AXIS CONTINUES TO ADVANCE INTO THE REGION...WITH LATEST RAP GUIDANCE SUGGESTING THE NOSE OF BUILDING WEAKISH INSTABILITY (MUCAPES NO BETTER THAN 150J/KG) APPROACHING WHITEFISH BAY BY 12Z. WHILE THE DOWNSTAIRS AIRMASS WILL REMAIN DRY NORTH OF THE SURFACE WARM FRONT...COULD THEORETICALLY CONTINUE TO SEE SOME POPUP SHOWERS JUST ABOUT ANYWHERE ACROSS THE REGION...BUT PROBABLY MOST PRONOUNCED NORTH OF THE BRIDGE. CLOUD COVER IS A BIG ISSUE AS WELL...AS SAID MOISTURE ADVECTION IS DRIVING A THICKER BAND OF CLOUDS NORTH OF M-32...THOUGH WITH THESE LIFTING NORTH WITH TIME. A SECONDARY AXIS OF MID CLOUDS IS DEVELOPING OVER THE LOWER LAKES/SOUTHERN WISCONSIN...AND MAY SEE THIS SLIP ACROSS THE REGION THROUGH MID MORNING. SUSPECT WE SHOULD SEE SOME SUNSHINE BREAK OUT NO LATER THAN LATE MORNING AS THE ELEVATED WARM FRONT MIXES NORTHWARD AND STRONGER THERMAL RIDGING POKES INTO NORTHERN MICHIGAN. THAT SETUP WILL LEAD US TO OUR SECOND CONVECTIVE CHANCE FOR THE DAY AS BETTER BOUNDARY LAYER MOISTURE SPILLS NORTHWARD...WITH DEW POINTS RISING THROUGH THE 60S. FORCING FOR ASCENT IS NOTHING TERRIBLY IMPRESSIVE FOR THE AFTERNOON...AND STRENGTHENING SYNOPTIC FLOW WILL PREVENT ANY LAKE BREEZE DEVELOPMENT. HOWEVER...CONTINUED WARM ADVECTION BELOW 800MB AND MOISTURE ADVECTION COMBINED WITH THE LIKELIHOOD FOR SOME TERRAIN-INDUCED FORCING IN MEAN SOUTHWEST FLOW SHOULD BE ENOUGH TO POP OFF ADDITIONAL ACTIVITY...MAINLY AFTER 17Z. INSTABILITY IS NOTHING HUGE...BUT AN 80/63 PARCEL SHOULD EASILY GIVE UP TO 1000 J/KG LATER TODAY PER CONSENSUS FORECAST RAOBS. BEST CHANCE FOR CONVECTION GIVEN THE SETUP SHOULD BE MAINLY ACROSS CENTRAL AND EASTERN HALF OF THE CWA...AS A LAKE MICHIGAN SHADOW WILL LIKELY BE PRESENT CLOSER TO THE COAST. SEVERE WEATHER THREAT DOESN`T LOOK OVERLY HIGH AS MID LEVEL (850-500MB) LAPSE RATES ARE RATHER PALTRY AND EFFECTIVE SHEAR VALUES ONLY PUSH ABOUT 25 KNOTS AT BEST...COURTESY OF A RATHER LAX FLOW REGIME ABOVE 400MB. HIGHS TODAY WILL BE WARMER...GENERALLY WARMING THROUGH THE LOWER 80S IN MANY AREAS. THE BETTER CHANCE FOR CONVECTION (SUCH AS IT IS) SHOULD ARRIVE LATE THIS EVENING AND TONIGHT AS THE STRONGER UPPER WAVE CROSSES SOUTHERN ONTARIO...DRIVING THE SURFACE FRONT THROUGH THE CWA ROUGHLY 06-12Z. BETTER MID LEVEL LAPSE RATE AXIS FOLDING INTO THE AREA SHOULD GIVE A LITTLE BOOST TO INSTABILITY...WITH MUCAPE VALUES CLIMBING TOWARD 1500 J/KG...MAINLY NORTHWEST HALF OF THE CWA THROUGH 06Z. AT THE SAME TIME...MORE PRONOUNCED MID LEVEL JET IS PROGGED TO ARRIVE JUST AHEAD OF THE BOUNDARY...SUPPORTING THE NOTION OF INCREASING EFFECTIVE SHEAR UP TOWARD 35-40 KNOTS. SHEAR VECTORS NEARLY PARALLEL TO THE LOW LEVEL FRONT CONTINUE TO SUGGEST A LINEAR STRUCTURE TO ANY CONVECTION...AND NOT OUT OF THE QUESTION STRONGER STORMS THAT FIRE OFF ACROSS NORTHERN WISCONSIN/CENTRAL U.P. WILL POSE A WIND (AND MAYBE MARGINAL HAIL) THREAT THROUGH LATE EVENING. CERTAINLY SOMETHING TO WATCH. OTHERWISE...A MILD START TO THE NIGHT AHEAD OF THE FRONT...WITH READINGS LIKELY STUCK IN THE UPPER 60S OR EVEN 70S THROUGH 06-09Z...BEFORE FALLING QUICKLY NORTHERN AREAS BEHIND THE BOUNDARY. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 407 AM EDT MON JUL 22 2013 THE VIGOROUS UPPER LEVEL SHORTWAVE EXITS INTO QUEBEC TUESDAY...WITH NW FLOW ALOFT PERSISTING OVER THE REGION. THE NEXT WAVE IS SET FOR THURSDAY NIGHT...WITH ADDITIONAL SHORTWAVE ENERGY EXPECTED TO ROLL THROUGH INTO THE WEEKEND. BY EARLY NEXT WORK WEEK...WE WILL STILL BE IN NW FLOW ALOFT...BUT WITH UPPER RIDGING STARTING TO WORK INTO THE CENTRAL PART OF THE COUNTRY. THIS UPPER RIDGING LOOKING TO ARRIVE IN THE GREAT LAKES BY THE MIDDLE PART OF THE NEXT WORK WEEK. TUESDAY THROUGH THURSDAY...THE SYSTEM COLD FRONT FROM A POTENT UPPER LEVEL SHORTWAVE WILL BE QUICKLY EXITING NE LOWER TUESDAY MORNING. THERE COULD STILL BE SOME LINGERING SHOWERS AND STORMS IN THE MORNING...BEFORE STRONG DRYING AND CAPPING DEVELOPS OVERHEAD. TEMPERATURES WILL BE COOLING OFF INTO THE DAY...BUT A SECONDARY COLD FRONT/SHOT OF COOLER AIR WORKS IN TO NORTHERN MICHIGAN LATE IN THE AFTERNOON AND OVERNIGHT. NW WINDS BECOME RATHER GUSTY THROUGH THE DAY...REACHING UP TO 30 MPH IN THE AFTERNOON. WINDS WILL SUBSIDE INTO THE NIGHT...BUT WILL NOT REALLY CALM DOWN UNTIL WEDNESDAY AND WEDNESDAY NIGHT AS HIGH PRESSURE SETTLES IN OVERHEAD. ON THURSDAY...THE NEXT SHORTWAVE WILL BE DROPPING INTO ONTARIO LATE IN THE DAY...WHILE THE ASSOCIATED LOW PRESSURE DIVES INTO LAKE SUPERIOR...AND THE COLD FRONT PUSHES THROUGH NW WISCONSIN. THURSDAY NIGHT THROUGH THE WEEKEND...THE WAA AHEAD OF THE AFOREMENTIONED SHORTWAVE/LOW PRESSURE IS RATHER UNIMPRESSIVE. TOTAL THETA-E ADVECTION AT THIS POINT...IS APPEARING LESS AGGRESSIVE THAN WITH WHAT IS EXPECTED WITH TODAY/TONIGHT`S FRONT. REGARDLESS...HEIGHT FALLS...INCREASING INSTABILITY AND FORCING WILL RESULT IN INCREASING CHANCES FOR SEEING SHOWERS AND THUNDERSTORMS THROUGH FRIDAY. THE EXACT TIMING AND SOUTHWARD EXTENT OF THE FRONT IS UNCERTAIN...BUT THE CONSENSUS HERE IS FOR THE FRONT TO SHALLOW OUT AND SLIP INTO FAR SOUTHERN LOWER BY FRIDAY NIGHT. AT THE SAME TIME...A MID LEVEL JET AND RIGHT ENTRANCE REGION OF THE UPPER JET EXITS BY LATE FRIDAY NIGHT/SATURDAY MORNING. DO BELIEVE THAT BASED ON THE PATTERN SEEN IN THE UPPER LEVELS...THAT WE WOULD SEE A RATHER QUIET PERIOD OF WEATHER INTO THE WEEKEND. THE ADDITIONAL ENERGY (TRACK...BASED ON MODEL CONSENSUS) IN THE NOW DEEP CLOSED LOW ALOFT...WORKS ON THE FRONTAL ZONE THAT IS TO OUR SOUTH PUTTING RENEWED CONVECTION SOUTH OF US. WILL JUST KEEP SMALLISH CHANCES FOR ADDITIONAL SHOWERS AND STORMS IN FOR SATURDAY...WHILE WE APPEAR TO GET ENTRENCHED IN DEEPER LOWER THETA-E AIR. TEMPERATURES IN THE MIDDLE AND UPPER 70S...WILL FALL INTO THE UPPER 60S AND LOWER 70S FOR THE UPCOMING WEEKEND. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 638 AM EDT MON JUL 22 2013 A WARM FRONT IS LIFTING THROUGH NRN MICHIGAN EARLY THIS MORNING...AND THE EARLIER ASSOCIATED LIGHT RAIN SHOWERS/SPRINKLES HAVE EXITED NE LOWER. COULD STILL SEE A FEW LIGHT SHOWERS POP OFF THROUGH MID MORNING...BUT A WEDGE OF DRIER AIR HAS FILLED IN OVER THE REGION. LOW LEVEL MOISTURE WILL ADVECT NORTHWARD AND INTO NRN MICHIGAN THROUGH THE DAY...AND THE SUNSHINE SEEN THIS MORNING WILL HELP DESTABILIZE THE ATMOSPHERE ENOUGH TO WHERE SCATTERED SHOWERS AND A FEW STORMS ARE EXPECTED TO POP OFF AS EARLY AS 15Z...BUT MORE SO THIS AFTERNOON. THE BEST CHANCE FOR POSSIBLE BRIEF MVFR CIGS/VSBYS WILL BE AT APN...WITH THE EXPECTED DEVELOPMENT JUST EAST OF PLN/TVC/MBL. THIS CONVECTION WILL DIE OFF INTO THE EVENING...BUT UPSTREAM THERE IS ANOTHER SHORTWAVE TROUGH ALOFT AND ASSOCIATED COLD FRONT THAT WILL BE PUSHING THROUGH OVERNIGHT. THESE FEATURES WILL HAVE A BETTER CHANCE FOR BRINGING SHOWERS AND STORMS TO ALL TAF SITES. THERE IS A CHANCE THAT A STORM OVERNIGHT WILL BE ABLE TO BECOME SEVERE WITH THE OUTSIDE POTENTIAL FOR DAMAGING WINDS AND LARGE HAIL. CHANCES WAY TOO SMALL FOR ANY ONE LOCATION TO ACTUALLY SEE THIS SEVERITY...MUCH LESS GET RAINED ON. AT MOST...WILL INTRO A VCTS/CB GROUP. DEVELOPING GUSTY SW WINDS THIS AFTERNOON WILL SHIFT OUT OF THE NW LATE IN THE TAF PERIOD BEHIND THE COLD FRONT. && .MARINE... ISSUED AT 407 AM EDT MON JUL 22 2013 LIGHTER SOUTHEAST WINDS THROUGH EARLY MORNING WILL SHIFT SOUTHWEST AND STRENGTHEN THROUGH THE DAY...OUT AHEAD OF A COLD FRONT SLIDING THROUGH THE UPPER MIDWEST. WIND SPEEDS MAY WELL REACH SMALL CRAFT ADVISORY LEVELS...PARTICULARLY ON LAKE MICHIGAN SOUTH OF GRAND TRAVERSE LIGHT WHERE COASTAL CONVERGENCE SHOULD HELP BOOST SPEEDS. THOSE STRONGER WINDS OF GENERALLY 10-20 KNOTS WILL CONTINUE THROUGH THE FIRST HALF OF THE NIGHT...BUT SHIFT NORTHWESTERLY WITH TIME AS THE FRONT BLOWS THROUGH. DO EXPECT TO SEE AT LEAST A BROKEN LINE OF SHOWERS AND STORMS ACCOMPANY THE FRONT...WHICH OF COURSE COULD PROVIDE SOME LOCALLY HIGHER WINDS/WAVES. THE FRONT WILL EXIT THE WATERS BY TUESDAY MORNING...WITH GUSTY NORTHERLY WINDS TAKING HOLD...AND ADDITIONAL SMALL CRAFT ADVISORIES LIKELY TO BE NEEDED. HIGH PRESSURE WILL WORK ITS WAY ACROSS THE WATERS INTO MIDWEEK... GIVING A RETURN TO LIGHT WINDS AND LOW WAVES TUESDAY NIGHT THROUGH THURSDAY. && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LH...NONE. LM...NONE. LS...NONE. && $$ UPDATE...JPB SYNOPSIS...SD SHORT TERM...DL LONG TERM...SD AVIATION...SD MARINE...DL
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1110 AM EDT MON JUL 22 2013 LATEST UPDATE... UPDATE/MARINE .SYNOPSIS... ISSUED AT 330 AM EDT MON JUL 22 2013 A WARM FRONT WILL BRING A FEW SHOWERS AND THUNDERSTORMS LATER TODAY AND THEN A COLD FRONT WILL BRING MORE SCATTERED SHOWERS AND STORMS TONIGHT INTO TUESDAY. FAIR AND COOLER WEATHER WILL ARRIVE BY LATE TUESDAY AND LAST THROUGH THURSDAY. TEMPERATURES WILL AVERAGE NEAR NORMAL LATE IN THE WEEK THROUGH NEXT WEEKEND. && .UPDATE... ISSUED AT 1110 AM EDT MON JUL 22 2013 DROPPED MAXIMUM TEMPERATURES TODAY SLIGHTLY MAINLY SOUTH OF I-96 TO ACCOUNT FOR THE COOLING EFFECTS OF EXTENSIVE PRECIPITATION OVERNIGHT AND RESIDUAL CLOUD COVER. ALSO RAISED PRECIPITATION CHANCES EAST OF US-131 BASED ON HRRR MODEL GUIDANCE AND TO BETTER AGREE WITH SURROUNDING OFFICES. MAIN FORECAST CONCERN THIS AFTERNOON WILL BE PRECIPITATION CHANCES OVERNIGHT WITH THE APPROACHING COLD FRONT. UPDATE ISSUED AT 537 AM EDT MON JUL 22 2013 A COUPLE OF SHOWERS DEVELOPED IN THE PAST HR...ESPECIALLY NEAR LWA. WENT AND ADDED A RISK FOR A FEW EARLY MORNING SHOWERS PRIMARILY SOUTH OF A BIV TO LAN LINE. && .SHORT TERM...(TODAY THROUGH WEDNESDAY AFTERNOON) ISSUED AT 330 AM EDT MON JUL 22 2013 AFTER SOME LINGERING EARLY MORNING SHOWERS OVER OUR SE FCST AREA DRY WX IS ANTICIPATED FOR THE REST OF THE MORNING IN THE WAKE OF THE DEPARTING MCV THAT BROUGHT THE ROUND OF RAIN AND STORMS YESTERDAY EVENING AND OVERNIGHT. SOME WAA SHOWERS AND A FEW STORMS WILL DEVELOP THIS AFTERNOON. A FAIR AMOUNT OF SUN AND SSW WINDS WILL HELP TO BOOST MAX TEMPS INTO THE LOWER TO MIDDLE 80S ACROSS MOST OF OUR AREA TODAY. THE COLD FRONT WILL MOVE IN FROM THE NW TONIGHT AND BRING SCATTERED SHOWERS AND STORMS WHICH WILL LAST THROUGH ABOUT MIDDAY TUESDAY BEFORE THE FRONT CLEARS OUR AREA. A COOLER AND DRIER AIRMASS WILL ADVECT IN BEHIND THAT FRONT AND MAX TEMPS WEDNESDAY WILL ONLY REACH THE 70S. .LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY) ISSUED AT 330 AM EDT MON JUL 22 2013 PATTERN IS LOOKING COOLER WITH TIME ESPECIALLY THIS WEEKEND. MODELS IN DECENT AGREEMENT IN SHOWING A COLD FRONT PUSHING THROUGH FRI NIGHT INTO SAT WITH A WAVE OF LOW PRESSURE FORMING ON IT OVER SOUTHERN LOWER MI. THIS SHOULD LEAD TO SHOWERS AND WITH INSTABILITY AROUND THUNDERSTORMS. IF THE NEW HIGH RES EURO IS CORRECT SAT COULD BE A RATHER WET DAY FOR THE AREA. NORTHERLY FLOW SETS UP BEHIND THE WAVE LEADING TO STRONG COLD AIR ADVECTION. 925 MB TEMPS FALL TO UNDER 10 DEG C 12Z SUN. IF THIS HAPPENS AND THE UPPER LOW DEVELOPS NORTH OF SUPERIOR AS SHOWN BY THE HIGH RES EURO ON SUN...LAKE ENHANCED MOISTURE MAY IMPACT THE FORECAST. I LOWERED TEMPERATURES OVER GUIDANCE FOR SAT NIGHT THROUGH SUN BASED ON THIS. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 537 AM EDT MON JUL 22 2013 LIGHT RAIN SOUTH OF KAZO TRYING TO WORK NORTH AT THIS TIME. PRECIPITATION IS FALLING OUT OF MID LEVEL CLOUDS...SO VFR WEATHER EXPECTED EVEN IF THE RAIN DOES MOVE IN. THE LOW LEVELS ARE MOIST SO AN INCREASED RISK FOR MVFR/IFR EXISTS...BUT CONFIDENCE THAT IT WILL OCCUR IS TOO LOW TO ADD IT TO THE FORECAST. THE NEXT BATCH OF RAIN WITH POSSIBLE THUNDERSTORMS ARRIVES IN KMKG FIRST AROUND 04Z...THEN THE RAIN TRACKS SOUTHEAST FOR THE REMAINDER OF THE NIGHT. WE MAY SEE MVFR CONDITIONS WITH THIS RAIN LATER TONIGHT. THE IFR OR LOWER CONDITIONS CURRENTLY IN WI...ARE EXPECTED TO NOT REACH THE TAF SITES TODAY. && .MARINE... ISSUED AT 1110 AM EDT MON JUL 22 2013 LATEST OMR SHOWS WAVEHEIGHTS GENERALLY BELOW 2 FEET...ALTHOUGH 3 FEET WAS REPORTED AT GRAND HAVEN. AS NOTED IN THE PREVIOUS DISCUSSION...WINDS AND WAVES WILL INCREASE TODAY. ALTHOUGH A SMALL CRAFT ADVISORY IS NOT ANTICIPATED...WE WILL HAVE TO WATCH THE BEACH HAZARD POTENTIAL /PRIMARILY INCREASING LONGSHORE CURRENTS/ AS IT EVOLVES THIS AFTERNOON AND EVENING. && .HYDROLOGY... ISSUED AT 330 AM EDT MON JUL 22 2013 NO HYDRO ISSUES. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. && $$ UPDATE...TJT SYNOPSIS...LAURENS SHORT TERM...LAURENS LONG TERM...MJS AVIATION...MJS HYDROLOGY...LAURENS MARINE...TJT
AREA FORECAST DISCUSSION
NWS GAYLORD MI
703 AM EDT MON JUL 22 2013 .SYNOPSIS... ISSUED AT 407 AM EDT MON JUL 22 2013 HIGH PRESSURE EXITS EAST TODAY WHILE LOW PRESSURE LIFTS THROUGH ONTARIO. THIS WILL DRAG A WARM FRONT AND A FEW SHOWERS ACROSS THE NORTH WOODS. CHANCES FOR SHOWERS AND THUNDERSTORMS THEN DEVELOPS THROUGH THE DAY...OUT AHEAD OF A COLD FRONT WHICH WILL SWEEP ACROSS NORTHERN MICHIGAN TONIGHT...PROVIDING THE BETTER CHANCE FOR SHOWERS AND STORMS. HIGH PRESSURE BUILDS IN AGAIN FOR THE LATTER HALF OF THE WORK WEEK...BRINGING COOLER AND LESS HUMID WEATHER BACK TO NORTHERN MICHIGAN. && .UPDATE... ISSUED AT 638 AM EDT MON JUL 22 2013 ONE SHORTWAVE TROUGH WAS EXITING NE LOWER ALONG WITH LIGHT RAIN SHOWERS AND SPRINKLES. A WEDGE OF DRIER AIR IS NOW FILLED IN ACROSS ALL OF NRN MICHIGAN...WITH SUNSHINE GETTING THE DAY STARTED OFF RIGHT. THE WARMING UNDER THE SUN...AND ADVECTION OF HIGHER SFC TDS NORTHWARD WITH LIGHT SOUTHERLY FLOW BEHIND THE WARM FRONT...WILL WORK IN TANDEM FOR CONVECTION TO BREAK OUT WITH THE ASSIST FROM OROGRAPHIC FLOW/TERRAIN INDUCED LIFT. NO CAP SEEN ON FCST SOUNDINGS STILL SUGGEST THAT SHOWERS AND A FEW STORMS COULD POP OFF AS EARLY AS LATE MORNING THROUGH AFTERNOON....MAINLY THE INTERIOR HIGHER TERRAIN AND NE LOWER...AS SOUTHERLY FLOW SHOULD STABILIZE THE BL ACROSS EASTERN UPPER. NO SEVERE STORMS ARE EXPECTED WITH TODAY`S ACTIVITY...BUT STILL WATCHING UPSTREAM NEXT SHORTWAVE AND COLD FRONT...WHICH WILL PROVIDE AT LEAST A LOW END CHANCE FOR A SEVERE STORM OR TWO. && .SHORT TERM...(TODAY THROUGH TONIGHT) ISSUED AT 407 AM EDT MON JUL 22 2013 INTERESTING LITTLE FORECAST OVER THE NEXT 24 HOURS...WITH MAIN CONCERN FOCUSED ON POTENTIAL FOR CONVECTION...SOME OF WHICH MAY POSE A SNEAKY SEVERE THREAT FOR A FEW SPOTS LATER THIS EVENING/TONIGHT. OVERALL UPPER PATTERN CONTINUES TO FEATURE BROAD UPPER TROUGHING ACROSS MUCH OF THE NORTHERN TIER...WITH MEAN NORTHWEST FLOW REGIME ALOFT...AND A RATHER POTENT SHORTWAVE WORKING THROUGH SOUTHERN MANITOBA. THERE IS A MODEST SURFACE LOW ASSOCIATED WITH THIS UPPER FEATURE...WITH ANALYSIS SHOWING A 999MB LOW JUST NORTH OF THE ND/MN BORDER...WITH A TRAILING COLD FRONT CROSSING EASTERN ND/SD AS OF 07Z. CLOSER TO HOME...A LOW LEVEL RIDGE AXIS IS NOW PARKED ACROSS THE NORTHEAST CONUS (BUT STILL TRYING TO INFLUENCE OUR WX LOCALLY)...WHILE A WARM FRONT IS GRADUALLY LIFTING BACK NORTH THROUGH THE LOWER LAKES. SAW A DECENT AMOUNT OF CONVECTION JUST NORTH OF THIS FEATURE OVER THE PAST 12 HOURS...HELPED ALONG BY A SECONDARY WEAKER SHORTWAVE TRAVERSING SOUTHERN WISCONSIN...AND WORKING IN TANDEM WITH GOBS MORE MOISTURE (DEW POINTS WELL INTO THE LOWER 70S) AS OPPOSED TO THE DRY AIRMASS THAT`S IN PLACE UP IN OUR NECK OF THE WOODS. WITH THAT SAID...RADAR HAS CONTINUED TO SHOW OCCASIONAL MAINLY LIGHT SHOWERS PERCOLATING ACROSS THE CWA...IN RESPONSE TO A STRONGER PUSH OF 925-800MB THETA-E ADVECTION UNDERWAY ON THE HEELS OF A MODEST LOW LEVEL JET FEATURE RIDING UP THE SPINE OF LAKE MICHIGAN. CONVECTIVE CHANCES THROUGH THE FORECAST PERIOD LOOK TO COME DURING A FEW PERIODS. THE FIRST IS THROUGH AND JUST BEYOND SUNRISE AS LOWER LEVEL THETA-E RIDGE AXIS CONTINUES TO ADVANCE INTO THE REGION...WITH LATEST RAP GUIDANCE SUGGESTING THE NOSE OF BUILDING WEAKISH INSTABILITY (MUCAPES NO BETTER THAN 150J/KG) APPROACHING WHITEFISH BAY BY 12Z. WHILE THE DOWNSTAIRS AIRMASS WILL REMAIN DRY NORTH OF THE SURFACE WARM FRONT...COULD THEORETICALLY CONTINUE TO SEE SOME POPUP SHOWERS JUST ABOUT ANYWHERE ACROSS THE REGION...BUT PROBABLY MOST PRONOUNCED NORTH OF THE BRIDGE. CLOUD COVER IS A BIG ISSUE AS WELL...AS SAID MOISTURE ADVECTION IS DRIVING A THICKER BAND OF CLOUDS NORTH OF M-32...THOUGH WITH THESE LIFTING NORTH WITH TIME. A SECONDARY AXIS OF MID CLOUDS IS DEVELOPING OVER THE LOWER LAKES/SOUTHERN WISCONSIN...AND MAY SEE THIS SLIP ACROSS THE REGION THROUGH MID MORNING. SUSPECT WE SHOULD SEE SOME SUNSHINE BREAK OUT NO LATER THAN LATE MORNING AS THE ELEVATED WARM FRONT MIXES NORTHWARD AND STRONGER THERMAL RIDGING POKES INTO NORTHERN MICHIGAN. THAT SETUP WILL LEAD US TO OUR SECOND CONVECTIVE CHANCE FOR THE DAY AS BETTER BOUNDARY LAYER MOISTURE SPILLS NORTHWARD...WITH DEW POINTS RISING THROUGH THE 60S. FORCING FOR ASCENT IS NOTHING TERRIBLY IMPRESSIVE FOR THE AFTERNOON...AND STRENGTHENING SYNOPTIC FLOW WILL PREVENT ANY LAKE BREEZE DEVELOPMENT. HOWEVER...CONTINUED WARM ADVECTION BELOW 800MB AND MOISTURE ADVECTION COMBINED WITH THE LIKELIHOOD FOR SOME TERRAIN-INDUCED FORCING IN MEAN SOUTHWEST FLOW SHOULD BE ENOUGH TO POP OFF ADDITIONAL ACTIVITY...MAINLY AFTER 17Z. INSTABILITY IS NOTHING HUGE...BUT AN 80/63 PARCEL SHOULD EASILY GIVE UP TO 1000 J/KG LATER TODAY PER CONSENSUS FORECAST RAOBS. BEST CHANCE FOR CONVECTION GIVEN THE SETUP SHOULD BE MAINLY ACROSS CENTRAL AND EASTERN HALF OF THE CWA...AS A LAKE MICHIGAN SHADOW WILL LIKELY BE PRESENT CLOSER TO THE COAST. SEVERE WEATHER THREAT DOESN`T LOOK OVERLY HIGH AS MID LEVEL (850-500MB) LAPSE RATES ARE RATHER PALTRY AND EFFECTIVE SHEAR VALUES ONLY PUSH ABOUT 25 KNOTS AT BEST...COURTESY OF A RATHER LAX FLOW REGIME ABOVE 400MB. HIGHS TODAY WILL BE WARMER...GENERALLY WARMING THROUGH THE LOWER 80S IN MANY AREAS. THE BETTER CHANCE FOR CONVECTION (SUCH AS IT IS) SHOULD ARRIVE LATE THIS EVENING AND TONIGHT AS THE STRONGER UPPER WAVE CROSSES SOUTHERN ONTARIO...DRIVING THE SURFACE FRONT THROUGH THE CWA ROUGHLY 06-12Z. BETTER MID LEVEL LAPSE RATE AXIS FOLDING INTO THE AREA SHOULD GIVE A LITTLE BOOST TO INSTABILITY...WITH MUCAPE VALUES CLIMBING TOWARD 1500 J/KG...MAINLY NORTHWEST HALF OF THE CWA THROUGH 06Z. AT THE SAME TIME...MORE PRONOUNCED MID LEVEL JET IS PROGGED TO ARRIVE JUST AHEAD OF THE BOUNDARY...SUPPORTING THE NOTION OF INCREASING EFFECTIVE SHEAR UP TOWARD 35-40 KNOTS. SHEAR VECTORS NEARLY PARALLEL TO THE LOW LEVEL FRONT CONTINUE TO SUGGEST A LINEAR STRUCTURE TO ANY CONVECTION...AND NOT OUT OF THE QUESTION STRONGER STORMS THAT FIRE OFF ACROSS NORTHERN WISCONSIN/CENTRAL U.P. WILL POSE A WIND (AND MAYBE MARGINAL HAIL) THREAT THROUGH LATE EVENING. CERTAINLY SOMETHING TO WATCH. OTHERWISE...A MILD START TO THE NIGHT AHEAD OF THE FRONT...WITH READINGS LIKELY STUCK IN THE UPPER 60S OR EVEN 70S THROUGH 06-09Z...BEFORE FALLING QUICKLY NORTHERN AREAS BEHIND THE BOUNDARY. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 407 AM EDT MON JUL 22 2013 THE VIGOROUS UPPER LEVEL SHORTWAVE EXITS INTO QUEBEC TUESDAY...WITH NW FLOW ALOFT PERSISTING OVER THE REGION. THE NEXT WAVE IS SET FOR THURSDAY NIGHT...WITH ADDITIONAL SHORTWAVE ENERGY EXPECTED TO ROLL THROUGH INTO THE WEEKEND. BY EARLY NEXT WORK WEEK...WE WILL STILL BE IN NW FLOW ALOFT...BUT WITH UPPER RIDGING STARTING TO WORK INTO THE CENTRAL PART OF THE COUNTRY. THIS UPPER RIDGING LOOKING TO ARRIVE IN THE GREAT LAKES BY THE MIDDLE PART OF THE NEXT WORK WEEK. TUESDAY THROUGH THURSDAY...THE SYSTEM COLD FRONT FROM A POTENT UPPER LEVEL SHORTWAVE WILL BE QUICKLY EXITING NE LOWER TUESDAY MORNING. THERE COULD STILL BE SOME LINGERING SHOWERS AND STORMS IN THE MORNING...BEFORE STRONG DRYING AND CAPPING DEVELOPS OVERHEAD. TEMPERATURES WILL BE COOLING OFF INTO THE DAY...BUT A SECONDARY COLD FRONT/SHOT OF COOLER AIR WORKS IN TO NORTHERN MICHIGAN LATE IN THE AFTERNOON AND OVERNIGHT. NW WINDS BECOME RATHER GUSTY THROUGH THE DAY...REACHING UP TO 30 MPH IN THE AFTERNOON. WINDS WILL SUBSIDE INTO THE NIGHT...BUT WILL NOT REALLY CALM DOWN UNTIL WEDNESDAY AND WEDNESDAY NIGHT AS HIGH PRESSURE SETTLES IN OVERHEAD. ON THURSDAY...THE NEXT SHORTWAVE WILL BE DROPPING INTO ONTARIO LATE IN THE DAY...WHILE THE ASSOCIATED LOW PRESSURE DIVES INTO LAKE SUPERIOR...AND THE COLD FRONT PUSHES THROUGH NW WISCONSIN. THURSDAY NIGHT THROUGH THE WEEKEND...THE WAA AHEAD OF THE AFOREMENTIONED SHORTWAVE/LOW PRESSURE IS RATHER UNIMPRESSIVE. TOTAL THETA-E ADVECTION AT THIS POINT...IS APPEARING LESS AGGRESSIVE THAN WITH WHAT IS EXPECTED WITH TODAY/TONIGHT`S FRONT. REGARDLESS...HEIGHT FALLS...INCREASING INSTABILITY AND FORCING WILL RESULT IN INCREASING CHANCES FOR SEEING SHOWERS AND THUNDERSTORMS THROUGH FRIDAY. THE EXACT TIMING AND SOUTHWARD EXTENT OF THE FRONT IS UNCERTAIN...BUT THE CONSENSUS HERE IS FOR THE FRONT TO SHALLOW OUT AND SLIP INTO FAR SOUTHERN LOWER BY FRIDAY NIGHT. AT THE SAME TIME...A MID LEVEL JET AND RIGHT ENTRANCE REGION OF THE UPPER JET EXITS BY LATE FRIDAY NIGHT/SATURDAY MORNING. DO BELIEVE THAT BASED ON THE PATTERN SEEN IN THE UPPER LEVELS...THAT WE WOULD SEE A RATHER QUIET PERIOD OF WEATHER INTO THE WEEKEND. THE ADDITIONAL ENERGY (TRACK...BASED ON MODEL CONSENSUS) IN THE NOW DEEP CLOSED LOW ALOFT...WORKS ON THE FRONTAL ZONE THAT IS TO OUR SOUTH PUTTING RENEWED CONVECTION SOUTH OF US. WILL JUST KEEP SMALLISH CHANCES FOR ADDITIONAL SHOWERS AND STORMS IN FOR SATURDAY...WHILE WE APPEAR TO GET ENTRENCHED IN DEEPER LOWER THETA-E AIR. TEMPERATURES IN THE MIDDLE AND UPPER 70S...WILL FALL INTO THE UPPER 60S AND LOWER 70S FOR THE UPCOMING WEEKEND. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 638 AM EDT MON JUL 22 2013 A WARM FRONT IS LIFTING THROUGH NRN MICHIGAN EARLY THIS MORNING...AND THE EARLIER ASSOCIATED LIGHT RAIN SHOWERS/SPRINKLES HAVE EXITED NE LOWER. COULD STILL SEE A FEW LIGHT SHOWERS POP OFF THROUGH MID MORNING...BUT A WEDGE OF DRIER AIR HAS FILLED IN OVER THE REGION. LOW LEVEL MOISTURE WILL ADVECT NORTHWARD AND INTO NRN MICHIGAN THROUGH THE DAY...AND THE SUNSHINE SEEN THIS MORNING WILL HELP DESTABILIZE THE ATMOSPHERE ENOUGH TO WHERE SCATTERED SHOWERS AND A FEW STORMS ARE EXPECTED TO POP OFF AS EARLY AS 15Z...BUT MORE SO THIS AFTERNOON. THE BEST CHANCE FOR POSSIBLE BRIEF MVFR CIGS/VSBYS WILL BE AT APN...WITH THE EXPECTED DEVELOPMENT JUST EAST OF PLN/TVC/MBL. THIS CONVECTION WILL DIE OFF INTO THE EVENING...BUT UPSTREAM THERE IS ANOTHER SHORTWAVE TROUGH ALOFT AND ASSOCIATED COLD FRONT THAT WILL BE PUSHING THROUGH OVERNIGHT. THESE FEATURES WILL HAVE A BETTER CHANCE FOR BRINGING SHOWERS AND STORMS TO ALL TAF SITES. THERE IS A CHANCE THAT A STORM OVERNIGHT WILL BE ABLE TO BECOME SEVERE WITH THE OUTSIDE POTENTIAL FOR DAMAGING WINDS AND LARGE HAIL. CHANCES WAY TOO SMALL FOR ANY ONE LOCATION TO ACTUALLY SEE THIS SEVERITY...MUCH LESS GET RAINED ON. AT MOST...WILL INTRO A VCTS/CB GROUP. DEVELOPING GUSTY SW WINDS THIS AFTERNOON WILL SHIFT OUT OF THE NW LATE IN THE TAF PERIOD BEHIND THE COLD FRONT. && .MARINE... ISSUED AT 407 AM EDT MON JUL 22 2013 LIGHTER SOUTHEAST WINDS THROUGH EARLY MORNING WILL SHIFT SOUTHWEST AND STRENGTHEN THROUGH THE DAY...OUT AHEAD OF A COLD FRONT SLIDING THROUGH THE UPPER MIDWEST. WIND SPEEDS MAY WELL REACH SMALL CRAFT ADVISORY LEVELS...PARTICULARLY ON LAKE MICHIGAN SOUTH OF GRAND TRAVERSE LIGHT WHERE COASTAL CONVERGENCE SHOULD HELP BOOST SPEEDS. THOSE STRONGER WINDS OF GENERALLY 10-20 KNOTS WILL CONTINUE THROUGH THE FIRST HALF OF THE NIGHT...BUT SHIFT NORTHWESTERLY WITH TIME AS THE FRONT BLOWS THROUGH. DO EXPECT TO SEE AT LEAST A BROKEN LINE OF SHOWERS AND STORMS ACCOMPANY THE FRONT...WHICH OF COURSE COULD PROVIDE SOME LOCALLY HIGHER WINDS/WAVES. THE FRONT WILL EXIT THE WATERS BY TUESDAY MORNING...WITH GUSTY NORTHERLY WINDS TAKING HOLD...AND ADDITIONAL SMALL CRAFT ADVISORIES LIKELY TO BE NEEDED. HIGH PRESSURE WILL WORK ITS WAY ACROSS THE WATERS INTO MIDWEEK... GIVING A RETURN TO LIGHT WINDS AND LOW WAVES TUESDAY NIGHT THROUGH THURSDAY. && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LH...NONE. LM...NONE. LS...NONE. && $$ UPDATE...SD SYNOPSIS...SD SHORT TERM...DL LONG TERM...SD AVIATION...SD MARINE...DL
AREA FORECAST DISCUSSION
NWS GAYLORD MI
457 AM EDT MON JUL 22 2013 .SYNOPSIS... ISSUED AT 407 AM EDT MON JUL 22 2013 HIGH PRESSURE EXITS EAST TODAY WHILE LOW PRESSURE LIFTS THROUGH ONTARIO. THIS WILL DRAG A WARM FRONT AND A FEW SHOWERS ACROSS THE NORTH WOODS. CHANCES FOR SHOWERS AND THUNDERSTORMS THEN DEVELOPS THROUGH THE DAY...OUT AHEAD OF A COLD FRONT WHICH WILL SWEEP ACROSS NORTHERN MICHIGAN TONIGHT...PROVIDING THE BETTER CHANCE FOR SHOWERS AND STORMS. HIGH PRESSURE BUILDS IN AGAIN FOR THE LATTER HALF OF THE WORK WEEK...BRINGING COOLER AND LESS HUMID WEATHER BACK TO NORTHERN MICHIGAN. && .SHORT TERM...(TODAY THROUGH TONIGHT) ISSUED AT 407 AM EDT MON JUL 22 2013 INTERESTING LITTLE FORECAST OVER THE NEXT 24 HOURS...WITH MAIN CONCERN FOCUSED ON POTENTIAL FOR CONVECTION...SOME OF WHICH MAY POSE A SNEAKY SEVERE THREAT FOR A FEW SPOTS LATER THIS EVENING/TONIGHT. OVERALL UPPER PATTERN CONTINUES TO FEATURE BROAD UPPER TROUGHING ACROSS MUCH OF THE NORTHERN TIER...WITH MEAN NORTHWEST FLOW REGIME ALOFT...AND A RATHER POTENT SHORTWAVE WORKING THROUGH SOUTHERN MANITOBA. THERE IS A MODEST SURFACE LOW ASSOCIATED WITH THIS UPPER FEATURE...WITH ANALYSIS SHOWING A 999MB LOW JUST NORTH OF THE ND/MN BORDER...WITH A TRAILING COLD FRONT CROSSING EASTERN ND/SD AS OF 07Z. CLOSER TO HOME...A LOW LEVEL RIDGE AXIS IS NOW PARKED ACROSS THE NORTHEAST CONUS (BUT STILL TRYING TO INFLUENCE OUR WX LOCALLY)...WHILE A WARM FRONT IS GRADUALLY LIFTING BACK NORTH THROUGH THE LOWER LAKES. SAW A DECENT AMOUNT OF CONVECTION JUST NORTH OF THIS FEATURE OVER THE PAST 12 HOURS...HELPED ALONG BY A SECONDARY WEAKER SHORTWAVE TRAVERSING SOUTHERN WISCONSIN...AND WORKING IN TANDEM WITH GOBS MORE MOISTURE (DEW POINTS WELL INTO THE LOWER 70S) AS OPPOSED TO THE DRY AIRMASS THAT`S IN PLACE UP IN OUR NECK OF THE WOODS. WITH THAT SAID...RADAR HAS CONTINUED TO SHOW OCCASIONAL MAINLY LIGHT SHOWERS PERCOLATING ACROSS THE CWA...IN RESPONSE TO A STRONGER PUSH OF 925-800MB THETA-E ADVECTION UNDERWAY ON THE HEELS OF A MODEST LOW LEVEL JET FEATURE RIDING UP THE SPINE OF LAKE MICHIGAN. CONVECTIVE CHANCES THROUGH THE FORECAST PERIOD LOOK TO COME DURING A FEW PERIODS. THE FIRST IS THROUGH AND JUST BEYOND SUNRISE AS LOWER LEVEL THETA-E RIDGE AXIS CONTINUES TO ADVANCE INTO THE REGION...WITH LATEST RAP GUIDANCE SUGGESTING THE NOSE OF BUILDING WEAKISH INSTABILITY (MUCAPES NO BETTER THAN 150J/KG) APPROACHING WHITEFISH BAY BY 12Z. WHILE THE DOWNSTAIRS AIRMASS WILL REMAIN DRY NORTH OF THE SURFACE WARM FRONT...COULD THEORETICALLY CONTINUE TO SEE SOME POPUP SHOWERS JUST ABOUT ANYWHERE ACROSS THE REGION...BUT PROBABLY MOST PRONOUNCED NORTH OF THE BRIDGE. CLOUD COVER IS A BIG ISSUE AS WELL...AS SAID MOISTURE ADVECTION IS DRIVING A THICKER BAND OF CLOUDS NORTH OF M-32...THOUGH WITH THESE LIFTING NORTH WITH TIME. A SECONDARY AXIS OF MID CLOUDS IS DEVELOPING OVER THE LOWER LAKES/SOUTHERN WISCONSIN...AND MAY SEE THIS SLIP ACROSS THE REGION THROUGH MID MORNING. SUSPECT WE SHOULD SEE SOME SUNSHINE BREAK OUT NO LATER THAN LATE MORNING AS THE ELEVATED WARM FRONT MIXES NORTHWARD AND STRONGER THERMAL RIDGING POKES INTO NORTHERN MICHIGAN. THAT SETUP WILL LEAD US TO OUR SECOND CONVECTIVE CHANCE FOR THE DAY AS BETTER BOUNDARY LAYER MOISTURE SPILLS NORTHWARD...WITH DEW POINTS RISING THROUGH THE 60S. FORCING FOR ASCENT IS NOTHING TERRIBLY IMPRESSIVE FOR THE AFTERNOON...AND STRENGTHENING SYNOPTIC FLOW WILL PREVENT ANY LAKE BREEZE DEVELOPMENT. HOWEVER...CONTINUED WARM ADVECTION BELOW 800MB AND MOISTURE ADVECTION COMBINED WITH THE LIKELIHOOD FOR SOME TERRAIN-INDUCED FORCING IN MEAN SOUTHWEST FLOW SHOULD BE ENOUGH TO POP OFF ADDITIONAL ACTIVITY...MAINLY AFTER 17Z. INSTABILITY IS NOTHING HUGE...BUT AN 80/63 PARCEL SHOULD EASILY GIVE UP TO 1000 J/KG LATER TODAY PER CONSENSUS FORECAST RAOBS. BEST CHANCE FOR CONVECTION GIVEN THE SETUP SHOULD BE MAINLY ACROSS CENTRAL AND EASTERN HALF OF THE CWA...AS A LAKE MICHIGAN SHADOW WILL LIKELY BE PRESENT CLOSER TO THE COAST. SEVERE WEATHER THREAT DOESN`T LOOK OVERLY HIGH AS MID LEVEL (850-500MB) LAPSE RATES ARE RATHER PALTRY AND EFFECTIVE SHEAR VALUES ONLY PUSH ABOUT 25 KNOTS AT BEST...COURTESY OF A RATHER LAX FLOW REGIME ABOVE 400MB. HIGHS TODAY WILL BE WARMER...GENERALLY WARMING THROUGH THE LOWER 80S IN MANY AREAS. THE BETTER CHANCE FOR CONVECTION (SUCH AS IT IS) SHOULD ARRIVE LATE THIS EVENING AND TONIGHT AS THE STRONGER UPPER WAVE CROSSES SOUTHERN ONTARIO...DRIVING THE SURFACE FRONT THROUGH THE CWA ROUGHLY 06-12Z. BETTER MID LEVEL LAPSE RATE AXIS FOLDING INTO THE AREA SHOULD GIVE A LITTLE BOOST TO INSTABILITY...WITH MUCAPE VALUES CLIMBING TOWARD 1500 J/KG...MAINLY NORTHWEST HALF OF THE CWA THROUGH 06Z. AT THE SAME TIME...MORE PRONOUNCED MID LEVEL JET IS PROGGED TO ARRIVE JUST AHEAD OF THE BOUNDARY...SUPPORTING THE NOTION OF INCREASING EFFECTIVE SHEAR UP TOWARD 35-40 KNOTS. SHEAR VECTORS NEARLY PARALLEL TO THE LOW LEVEL FRONT CONTINUE TO SUGGEST A LINEAR STRUCTURE TO ANY CONVECTION...AND NOT OUT OF THE QUESTION STRONGER STORMS THAT FIRE OFF ACROSS NORTHERN WISCONSIN/CENTRAL U.P. WILL POSE A WIND (AND MAYBE MARGINAL HAIL) THREAT THROUGH LATE EVENING. CERTAINLY SOMETHING TO WATCH. OTHERWISE...A MILD START TO THE NIGHT AHEAD OF THE FRONT...WITH READINGS LIKELY STUCK IN THE UPPER 60S OR EVEN 70S THROUGH 06-09Z...BEFORE FALLING QUICKLY NORTHERN AREAS BEHIND THE BOUNDARY. && .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 407 AM EDT MON JUL 22 2013 THE VIGOROUS UPPER LEVEL SHORTWAVE EXITS INTO QUEBEC TUESDAY...WITH NW FLOW ALOFT PERSISTING OVER THE REGION. THE NEXT WAVE IS SET FOR THURSDAY NIGHT...WITH ADDITIONAL SHORTWAVE ENERGY EXPECTED TO ROLL THROUGH INTO THE WEEKEND. BY EARLY NEXT WORK WEEK...WE WILL STILL BE IN NW FLOW ALOFT...BUT WITH UPPER RIDGING STARTING TO WORK INTO THE CENTRAL PART OF THE COUNTRY. THIS UPPER RIDGING LOOKING TO ARRIVE IN THE GREAT LAKES BY THE MIDDLE PART OF THE NEXT WORK WEEK. TUESDAY THROUGH THURSDAY...THE SYSTEM COLD FRONT FROM A POTENT UPPER LEVEL SHORTWAVE WILL BE QUICKLY EXITING NE LOWER TUESDAY MORNING. THERE COULD STILL BE SOME LINGERING SHOWERS AND STORMS IN THE MORNING...BEFORE STRONG DRYING AND CAPPING DEVELOPS OVERHEAD. TEMPERATURES WILL BE COOLING OFF INTO THE DAY...BUT A SECONDARY COLD FRONT/SHOT OF COOLER AIR WORKS IN TO NORTHERN MICHIGAN LATE IN THE AFTERNOON AND OVERNIGHT. NW WINDS BECOME RATHER GUSTY THROUGH THE DAY...REACHING UP TO 30 MPH IN THE AFTERNOON. WINDS WILL SUBSIDE INTO THE NIGHT...BUT WILL NOT REALLY CALM DOWN UNTIL WEDNESDAY AND WEDNESDAY NIGHT AS HIGH PRESSURE SETTLES IN OVERHEAD. ON THURSDAY...THE NEXT SHORTWAVE WILL BE DROPPING INTO ONTARIO LATE IN THE DAY...WHILE THE ASSOCIATED LOW PRESSURE DIVES INTO LAKE SUPERIOR...AND THE COLD FRONT PUSHES THROUGH NW WISCONSIN. THURSDAY NIGHT THROUGH THE WEEKEND...THE WAA AHEAD OF THE AFOREMENTIONED SHORTWAVE/LOW PRESSURE IS RATHER UNIMPRESSIVE. TOTAL THETA-E ADVECTION AT THIS POINT...IS APPEARING LESS AGGRESSIVE THAN WITH WHAT IS EXPECTED WITH TODAY/TONIGHT`S FRONT. REGARDLESS...HEIGHT FALLS...INCREASING INSTABILITY AND FORCING WILL RESULT IN INCREASING CHANCES FOR SEEING SHOWERS AND THUNDERSTORMS THROUGH FRIDAY. THE EXACT TIMING AND SOUTHWARD EXTENT OF THE FRONT IS UNCERTAIN...BUT THE CONSENSUS HERE IS FOR THE FRONT TO SHALLOW OUT AND SLIP INTO FAR SOUTHERN LOWER BY FRIDAY NIGHT. AT THE SAME TIME...A MID LEVEL JET AND RIGHT ENTRANCE REGION OF THE UPPER JET EXITS BY LATE FRIDAY NIGHT/SATURDAY MORNING. DO BELIEVE THAT BASED ON THE PATTERN SEEN IN THE UPPER LEVELS...THAT WE WOULD SEE A RATHER QUIET PERIOD OF WEATHER INTO THE WEEKEND. THE ADDITIONAL ENERGY (TRACK...BASED ON MODEL CONSENSUS) IN THE NOW DEEP CLOSED LOW ALOFT...WORKS ON THE FRONTAL ZONE THAT IS TO OUR SOUTH PUTTING RENEWED CONVECTION SOUTH OF US. WILL JUST KEEP SMALLISH CHANCES FOR ADDITIONAL SHOWERS AND STORMS IN FOR SATURDAY...WHILE WE APPEAR TO GET ENTRENCHED IN DEEPER LOWER THETA-E AIR. TEMPERATURES IN THE MIDDLE AND UPPER 70S...WILL FALL INTO THE UPPER 60S AND LOWER 70S FOR THE UPCOMING WEEKEND. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 216 AM EDT MON JUL 22 2013 RETURN SOUTHERLY FLOW ON THE BACKSIDE OF THE SURFACE HIGH WILL ALLOW LOW/MID LEVEL CLOUDS TO MOVE INTO AND/OR DEVELOP ACROSS NORTHERN LOWER MICHIGAN THE REST OF THE NIGHT AND INTO THE AFTERNOON HOURS. HEATING OF THE DAY SHOULD ALSO HELP FIRE OFF A FEW SHOWERS AND THUNDERSTORMS...MOST LIKELY TO IMPACT PLN AND APN AWAY FROM THE STABILIZING INFLUENCES OF LAKE MICHIGAN. A COLD WILL APPROACH THE AREA THROUGH THE LATE EVENING AND OVERNIGHT HOURS...GIVING BETTER CHANCES FOR MORE WIDESPREAD SHOWERS AND STORMS. OVERALL...VFR CONDITIONS WILL BE THE RULE...THOUGH OF COURSE...LOCALIZED WORSE CONDITIONS ARE ALWAYS POSSIBLE NEAR ANY THUNDERSTORMS. LIGHT SOUTHEAST WINDS THROUGH SUNRISE WILL GIVE WAY TO SOME GUSTY SOUTHWEST CONDITIONS THROUGH THE DAY...WITH GUSTS OF 15-20 KNOTS POSSIBLE. LOW LEVEL WIND SHEAR WILL BECOME AN ISSUE TOWARD SUNSET. && .MARINE... ISSUED AT 407 AM EDT MON JUL 22 2013 LIGHTER SOUTHEAST WINDS THROUGH EARLY MORNING WILL SHIFT SOUTHWEST AND STRENGTHEN THROUGH THE DAY...OUT AHEAD OF A COLD FRONT SLIDING THROUGH THE UPPER MIDWEST. WIND SPEEDS MAY WELL REACH SMALL CRAFT ADVISORY LEVELS...PARTICULARLY ON LAKE MICHIGAN SOUTH OF GRAND TRAVERSE LIGHT WHERE COASTAL CONVERGENCE SHOULD HELP BOOST SPEEDS. THOSE STRONGER WINDS OF GENERALLY 10-20 KNOTS WILL CONTINUE THROUGH THE FIRST HALF OF THE NIGHT...BUT SHIFT NORTHWESTERLY WITH TIME AS THE FRONT BLOWS THROUGH. DO EXPECT TO SEE AT LEAST A BROKEN LINE OF SHOWERS AND STORMS ACCOMPANY THE FRONT...WHICH OF COURSE COULD PROVIDE SOME LOCALLY HIGHER WINDS/WAVES. THE FRONT WILL EXIT THE WATERS BY TUESDAY MORNING...WITH GUSTY NORTHERLY WINDS TAKING HOLD...AND ADDITIONAL SMALL CRAFT ADVISORIES LIKELY TO BE NEEDED. HIGH PRESSURE WILL WORK ITS WAY ACROSS THE WATERS INTO MIDWEEK... GIVING A RETURN TO LIGHT WINDS AND LOW WAVES TUESDAY NIGHT THROUGH THURSDAY. && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LH...NONE. LM...NONE. LS...NONE. && $$ SYNOPSIS...SD SHORT TERM...DL LONG TERM...SD AVIATION...LAWRENCE MARINE...DL
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
449 AM EDT MON JUL 22 2013 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 410 PM EDT SUN JUL 21 2013 WV IMAGERY AND RUC ANALYSIS INDICATED MID/UPPER LEVEL LOWS OVER NE CANADA AND NRN BC RESULTING IN ZONAL TO WNW FLOW OVER SRN CANADA AND THE NRN CONUS. AN AREA OF CONVECTION HAS PERSISTED AHEAD OF PROMINENT SHORTWAVE TROUGH LOCATED OVER SRN SASK. THE COMBINATION OF A WEAK SHRTWV AND WAA AHEAD OF A WARM FRONT OVER IA SUPPORTED ANOTHER AREA OF SHRA/TSRA OVER CNTRL/SRN WI. TONIGHT...RADAR AND SHORT RANGE MODELS SUGGEST THAT ANY SHRA/TSRA ASSOCIATED WITH THE WI SHRTWV WILL NOT IMPACT THE CWA THIS EVENING. LINEAR EXTRAPOLATION OF THE SASK SHRTWV AND CONVECTION MOVING INTO THE SW CORNER OF MANITOBA WOULD BRING THE PCPN WITH THIS FEATURE INTO WRN UPPER MI BTWN 09Z-11Z. HOWEVER...AS THIS FEATURE MOVES INTO THE AIRMASS OVER THE NRN LAKES AND AWAY FROM THE MORE FAVORABLE MUCAPE OVER NRN MN...EXPECT THAT THE CONVECTION WILL WEAKEN. SO...THE FCST ONLY MENTIONS CHANCE POPS WITH ISOLD TS POSSIBLE OVERNIGHT. MONDAY...AFTER THE INITIAL BATCH OF SHRA/TSRA MOVES THROUGH MAINLY THE NW CWA EARLY MONDAY...THE FORECAST BECOMES MORE UNCERTAIN. THE AMOUNT OF DAYTIME WARMING AND RESULTING INSTABILITY WILL BE IMPACTED BY LINGERING CLOUD COVER IN THE WAA REGIME. IF THE CLOUDS BREAK UP ENOUGH AND TEMPS CLIMB TO AROUND 80 AS FCST WITH DEWPOINTS LOWER 60S...MLCAPE VALUES WOULD PUSH INTO THE 1000-1500 J/KG RANGE. STRONG LOW LEVEL AND A VEERING WIND PROFILE IS EXPECTED WITH 0-6KM BULK SHEAR TO AROUND 40 KT WITH CURVED HODOGRAPHS. THAT AMOUNT OF INSTABILITY COMBINED WITH A FAVORABLE SHEAR PROFILE WOULD SUPPORT POTENTIAL FOR SEVERE STORMS INCLUDING ISOLATED SUPERCELLS. THE MAIN TRIGGER FOR CONVECTION WOULD BE THE LIMITED FORCING WITH THE NRN ONTARIO SHRTWV TAIL ALONG WITH A PREFRONTAL TROUGH AND LAKE BREEZE BOUNDARIES AHEAD OF THE MAIN COLD FRONT MOVING INTO THE AREA DURING THE EVENING. HOWEVER...THE SEVERE WEATHER THREAT WILL BE CONDITIONAL...DEPENDENT ON THE AMOUNT OF INSTABILITY THAT DEVELOPS. THE GREATEST CHANCE FOR HIGHER CAPE VALUES IS EXPECTED NEAR THE WI BORDER FROM IWD-IMT IN LINE WITH SPC SREF SVR CALIBRATED PROB AND SPC OUTLOOK. THERE IS ALSO SOME UNCERTAINTY WITH TIMING...BUT THE GREATEST CHANCES WOULD LIKELY FROM W INTO CNTRL UPPER MI. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 449 AM EDT MON JUL 22 2013 TUESDAY...THE CWA WILL BE BETWEEN A DEPARTING SFC LOW NEAR JAMES BAY AND A SFC HIGH OVER NW MN AT 12Z. THE TIGHT PRESSURE BETWEEN THE SYSTEM AND BEHIND THE COLD FRONT THAT MOVED THROUGH MON EVENING/NIGHT WILL LEAD TO GUSTY NLY WINDS...BUT THE GRADIENT AND WINDS WILL DECREASE LATE IN THE DAY. BECAUSE OF THE GUSTY WINDS...WAVES WILL INCREASE AND ASSOCIATED SWIM RISK WILL BE HIGH. TEMPS WILL BE COOLER THAN TODAY...WITH HIGHS IN THE 60S NEAR LAKE SUPERIOR TO AROUND 70 WELL INLAND. TUESDAY NIGHT...TEMPS WILL FALL TO OR BELOW 40F OVER PARTS OF THE INTERIOR W DUE TO CLEAR SKIS AND CALM WINDS. WEDNESDAY...INCLUDED SLIGHT POPS IN THE AFTERNOON AS MODELS CONTINUE TO INDICATE A CONVECTIVELY INDUCED SHORTWAVE MOVING THROUGH NRN WI. NOT TOO SURE ABOUT WHAT WILL END UP HAPPENING WITH THE SHORTWAVE...BUT THOUGHT IT WAS WORTH THE SLIGHT POPS. TEMPS WILL BE A BIT WARMER THAN TUESDAY...WITH HIGHS IN THE MID 60S NEAR LAKE SUPERIOR TO THE MID 70S INLAND. UNCERTAINTY INCREASES ON A DAILY BASIS WED NIGHT THROUGH SUN AS MODELS BRING MULTIPLE ROUNDS OF UPPER LEVEL ENERGY INTO THE REGION...BUT DIFFER SIGNIFICANTLY BETWEEN MODELS AND BETWEEN RUNS ON THE STRENGTH/PLACEMENT OF THAT ENERGY...WHICH WILL PLAY A CRITICAL ROLE IN PRECIP CHANCES LATE IN THE WEEK AND INTO THE WEEKEND. WILL JUST GO WITH THE CONSENSUS GUIDANCE DUE TO THE UNCERTAINTY...BUT WILL NOT ALLOW POPS BE GET TOO HIGH. TEMPS ARE ALSO UNCERTAIN...BUT IT APPEARS A WARMER DAY WILL BE IN STORE FOR THU...WITH COOLING CONDITIONS FRIDAY INTO THE WEEKEND. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 248 AM EDT MON JUL 22 2013 VFR CONDITIONS ARE EXPECTED TO PERSIST THROUGH THE PERIOD. EXPECT INCREASING MID CLOUDS LATE TONIGHT INTO MONDAY MORNING AHEAD OF AN APPROACHING DISTURBANCE. SOME SHRA ARE POSSIBLE AT ALL SITES MON MORNING AND TRIED TO TIME THESE WITH EITHER PROB30 GROUPS OR PREVAILING. FRONT COMES THROUGH BY EVENING AND SWITCHES THE WIND TO THE NORTHWEST. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 410 PM EDT SUN JUL 21 2013 SRLY WINDS WILL INCREASE TO AROUND 20 KNOTS LATE TONIGHT AND MONDAY AHEAD OF A LOW PRESSURE TROUGH MOVING THROUGH THE AREA. NORTH TO NORTHWEST WINDS WILL THEN INCREASE TO 20-25 KNOTS BY LATE MONDAY NIGHT INTO TUESDAY BEHIND THE TROUGH/COLD FRONT MOVING THROUGH THE REGION. WINDS ARE THEN EXPECTED TO REMAIN BELOW 20 KNOTS TUE NIGHT THROUGH THURSDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...TITUS AVIATION...07 MARINE...JLB
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
101 PM CDT MON JUL 22 2013 .UPDATE... FOR 18Z AVIATION DISCUSSION BELOW && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 359 AM CDT MON JUL 22 2013 EARLY MORNING WATER VAPOR IMAGERY FEATURES A WELL-DEFINED SHORTWAVE TROUGH OVER SOUTHEASTERN MANITOBA AND NORTHWESTERN ONTARIO...WHILE SURFACE ANALYSIS ILLUSTRATES THE ASSOCIATED COLD FRONT STRETCHING FROM NORTHWESTERN MN ACROSS THE EASTERN DAKOTAS. SHOWERS AND THUNDERSTORMS HAVE DEVELOPED AS FAR SOUTH AS WEST CENTRAL MN OVERNIGHT IN RESPONSE TO MODEST LOW LEVEL WARM AIR/MOISTURE ADVECTION AHEAD OF THE TROUGH. THE 22.06Z RAP 925-850MB MOISTURE TRANSPORT MAGNITUDE CORRELATES WELL WITH THE CURRENT COVERAGE/LOCATION OF CONVECTION ON RADAR...WHICH GRADUALLY SHIFTS SOUTHEAST ACROSS THE FORECAST AREA DURING THE MORNING HOURS. THE ACTIVITY WANES AFTER 14-15Z WITH THE VEERING OF THE LLJ...BUT NOT BEFORE REACHING THE TWIN CITIES. THIS SCENARIO IS SUPPORTED BY THE 22.03Z HOPWRF REFLECTIVITY FORECAST...WHICH BRINGS DEINTENSIFYING SHOWERS INTO EAST CENTRAL MN BETWEEN 11Z AND 15Z THIS MORNING. THERE SHOULD THEN BE A BIT OF A LULL IN THE ACTIVITY...UNTIL DIURNAL WARMING TRIGGERS THUNDERSTORM RE-DEVELOPMENT ALONG THE FRONT DURING THE AFTERNOON. BY 18Z...THE BOUNDARY SHOULD BE NEARLY STRADDLING THE INTERSTATE 35 CORRIDOR...WHICH ESSENTIALLY MEANS THE THREAT FOR STRONG TO SEVERE STORMS WILL LIE FROM THE TWIN CITIES TO SOUTH CENTRAL MN...EASTWARD ACROSS WEST CENTRAL WI. THE CONVERGENCE ALONG THE FRONT LOCALLY IS NOT FANTASTIC...BUT PROGGED INSTABILITY /MUCAPES OF 2500-3000 J/KG AND LIFTED INDICES AROUND -4C/ AND BULK SHEAR VALUES AROUND 35 KTS COULD BE SUFFICIENT TO GENERATE A FEW FEISTIER STORMS PRIMARILY ALONG/EAST OF INTERSTATE 35. CONVECTION SHIFTS OUT OF THE AREA FAIRLY SWIFTLY THIS EVENING AS THE FRONT EXITS...WITH CLEARING SKIES AFTER MIDNIGHT. HIGH TEMPERATURES TODAY SHOULD RANGE FROM THE UPPER 70S /WEST CENTRAL MN/...TO THE MID AND UPPER 80S ACROSS THE REMAINDER OF THE AREA. IT WILL ALSO BE A BIT BREEZY IN THE WAKE OF THE FRONT...WITH GUSTS TO AROUND 25 MPH THIS AFTERNOON AND EARLY EVENING. LOWS TONIGHT WILL BE RIGHT AROUND LATE JULY NORMS IN THE UPPER 50S AND LOWER 60S. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 359 AM CDT MON JUL 22 2013 MAIN THEMES FOR THE EXTENDED IS THAT ONE...IT LOOKS INCREDIBLY PLEASANT FOR JULY...WITH TEMPERATURES MAINLY BELOW NORMAL AND DEWPS IN THE 50S WITH OCCASIONAL 60S. THE OTHER THEME IS A LONG LINE OF CHANCE/SLIGHT CHANCE POPS FOR THE SECOND HALF OF THIS WEEK AS A BOUNDARY GETS HUNG UP BENEATH A SEASONABLY STRONG NW FLOW ALOFT. THE DOMINATE UPPER AIR FEATURE THROUGH THE LONG TERM WILL BE A SEASONABLY STRONG CLOSED UPPER LOW THAT WILL BE OSCILLATING IN STRENGTH/POSITION ACROSS ERN CANADA AS UPPER RIDGING REMAINS ACROSS THE ROCKIES. THIS PATTERN WILL KEEP US IN NW FLOW AND THE PLEASANT CONDITIONS. GIVEN THE MODEST MID AND UPPER LEVEL JETTING THAT WILL BE OVERHEAD MUCH OF THE TIME...WILL SEE SEVERAL WEAK DISTURBANCES RIPPLE THROUGH THE FLOW...BUT THERE IS MUCH DISAGREEMENT AMONGST MODELS ON TIMING/STRENGTH/PLACEMENT OF ALL THESE WAVES...WHICH IS WHY THE FORECAST IS LITTERED WITH LOW POPS FROM WEDNESDAY THROUGH SATURDAY. AT THE SFC...HIGH PRESSURE WILL DOMINATE THRU TUESDAY IN THE WAKE OF TODAYS FRONT. ANOTHER WEAK AND RATHER DIFFUSE FRONT WILL WORK INTO THE AREA ON WEDNESDAY...WHEN IT RUNS INTO THE HIGH PRESSURE AND MEDIUM RANGE MODELS QUICKLY DIVERGE ON WHERE IT GOES FROM THERE. THE GEM IS THE MOST AGGRESSIVE WITH MOVING IT OUT ON THURSDAY...THE ECMWF HAS PICKED FRIDAY...AND THE GFS WAITS UNTIL SATURDAY TO FINALLY START PUSHING IT SOUTH OF MN. THIS TIMING DIFFERENCE IS KEYED TO HOW QUICKLY EACH MODEL DEEPENS AN H5 LOW NORTH OF LAKE SUPERIOR AT THE END OF THE WEEK. AS YOU CAN IMAGINE...THE GEM IS THE DEEPEST/MOST AGGRESSIVE WITH THIS...WHILE THE GFS IS THE SLOWEST OF THE BUNCH. FOR PRECIP POTENTIAL THIS WEEK...IT IS EASIER TO FIND NEGATIVES THAN IT IS POSITIVES. THE BIGGEST ISSUE DURING THE LONG TERM IS LLJ FORCING AND CONVERGENCE ALONG THE BOUNDARY LOOK WEAK...RESULTING IN A LOW CONFIDENCE POP FORECAST. BEST CHANCES FOR STORMS THOUGH LOOK TO BE WEDNESDAY/WEDNESDAY NIGHT AS BOUNDARY INITIALLY SETTLES IN...THEN AGAIN FRIDAY/FRIDAY NIGHT...OR WHENEVER IT GETS KICKED OUT. GIVEN THE WEAK LOW LEVEL FORCING...THE SEVERE THREAT LOOKS MINIMAL...AND WITH NW FLOW ALOFT...PWATS NEVER LOOK TO STRAY TOO FAR ABOVE THE NORMAL FOR JULY /1.2-1.3 INCHES/...SO NOT SEEING THE POTENTIAL FOR COPIOUS AMOUNTS OF RAINFALL EITHER. ABOUT THE ONLY POSITIVE FOR THIS WEEK IS THAT POOLING OF MOISTURE ALONG THE BOUNDARY WILL PROMOTE THE DEVELOPMENT OF A COUPLE THOUSAND J/KG OF MUCAPE TO WORK WITH MOST AFTERNOONS...WHICH WOULD SUPPORT THE IDEA OF SCT STORMS UNTIL THE BOUNDARY IS KICKED SOUTH OF HERE. ON THE TEMPERATURE FRONT...NOT ONLY ARE THERE CURRENTLY NO SIGNS OF WARM AIR THIS WEEK...BUT FOR THE REST OF THE MONTH...THE GFS AND ECMWF KEEP H85 TEMPS BELOW 20C. IF THAT ENDS UP HAPPENING...THEN WE MAY HAVE VERY WELL SEEN OUR LAST 90S OF THE MONTH BACK ON THE 18TH. IT IS EVEN LOOKING LIKE THERE WILL BE THE POTENTIAL FOR LOWS WEDNESDAY MORNING INTO THE 40S ACROSS PARTS OF WRN WI. IN FACT...THE 22.00 MAV GUIDANCE IS CURRENTLY FORECASTING TEMPERATURES NEAR RECORD LOWS OUT IN WRN WI FOR WEDNESDAY MORNING /48 FROM 1971 IS THE MARK TO BEAT AT EAU/. IF WE CAN MIX DEWPOINTS OUT AS MUCH AS THE MIXED LAYER DEWPS FROM THE NAM/GFS INDICATE FOR TUESDAY...THEN WE MAY BE ABLE MAKE A RUN AT THAT RECORD. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1245 PM CDT MON JUL 22 2013 THE COLD FRONT NOW EXTENDS FROM ROUGHLY SIOUX FALLS...TO THE WESTERN TWIN CITIES METRO...TO JUST SOUTHEAST OF DULUTH. SO FAR...THE FRONT IS JUST MANAGING TOWERING CUMULUS CLOUDS WITH CLOUDS BASES NEAR 3000 FT IN MOST LOCATIONS. A BRIEF PERIOD /1-3 HOURS/ OF MVFR CEILINGS IS POSSIBLE WITH THE COLD FRONT. WE ARE ALSO SEEING SOME SHOWERS DEVELOP IN NORTHWEST WI...BUT MINNESOTA AND WESTERN CENTRAL WI REMAIN STORM FREE AT THIS POINT. KEAU HAS THE BEST CHANCE FOR THUNDER. WE NOW THINK STORMS WILL MISS ALL THE OTHER TAF SITES BESIDES KEAU. KMSP... THE COLD FRONT /WITH A WIND SHIFT TO THE W-NW/ PASSED BY THE OFFICE HERE IN CHANHASSEN AT ABOUT 1245 PM...SO IT WILL BE AT THE AIRPORT WITHIN 30 MINUTES OR SO. GIVEN THAT THE STORM ACTIVITY HAS BEEN SUPPRESSED UP UNTIL NOW...WE THINK THERE IS NOT ENOUGH TIME TO DEVELOP STORMS BEFORE THE COLD FRONT PASSES THROUGH. STORM CHANCES LOOK BETTER 50-75 MILES EAST OF THE AIRPORT. COULD HAVE LINGERING STRATO CU WITH A SCT-BKN 2500-3500 FT DECK LATE THIS AFTERNOON OR EARLY EVENING...BUT THE MORE WIDESPREAD CLOUDS SHOULD REMAIN IN NORTHERN/WESTERN MN. NO AVIATION WEATHER CONCERNS TOMORROW. /OUTLOOK FOR KMSP/ TUE/TUE NIGHT...VFR. WINDS N 5 TO 10 KT. WED...VFR. CHANCE OF SHRA/TSRA LATE NIGHT. WINDS S 5 KT. THU...CHC SHRA/TSRA. VFR OUTSIDE OF SHRA/TSRA. WINDS WSW 5 KT. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...LS LONG TERM...MPG AVIATION...CLF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
640 AM CDT MON JUL 22 2013 .UPDATE... FOR 12Z AVIATION DISCUSSION BELOW && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 359 AM CDT MON JUL 22 2013 EARLY MORNING WATER VAPOR IMAGERY FEATURES A WELL-DEFINED SHORTWAVE TROUGH OVER SOUTHEASTERN MANITOBA AND NORTHWESTERN ONTARIO...WHILE SURFACE ANALYSIS ILLUSTRATES THE ASSOCIATED COLD FRONT STRETCHING FROM NORTHWESTERN MN ACROSS THE EASTERN DAKOTAS. SHOWERS AND THUNDERSTORMS HAVE DEVELOPED AS FAR SOUTH AS WEST CENTRAL MN OVERNIGHT IN RESPONSE TO MODEST LOW LEVEL WARM AIR/MOISTURE ADVECTION AHEAD OF THE TROUGH. THE 22.06Z RAP 925-850MB MOISTURE TRANSPORT MAGNITUDE CORRELATES WELL WITH THE CURRENT COVERAGE/LOCATION OF CONVECTION ON RADAR...WHICH GRADUALLY SHIFTS SOUTHEAST ACROSS THE FORECAST AREA DURING THE MORNING HOURS. THE ACTIVITY WANES AFTER 14-15Z WITH THE VEERING OF THE LLJ...BUT NOT BEFORE REACHING THE TWIN CITIES. THIS SCENARIO IS SUPPORTED BY THE 22.03Z HOPWRF REFLECTIVITY FORECAST...WHICH BRINGS DEINTENSIFYING SHOWERS INTO EAST CENTRAL MN BETWEEN 11Z AND 15Z THIS MORNING. THERE SHOULD THEN BE A BIT OF A LULL IN THE ACTIVITY...UNTIL DIURNAL WARMING TRIGGERS THUNDERSTORM RE-DEVELOPMENT ALONG THE FRONT DURING THE AFTERNOON. BY 18Z...THE BOUNDARY SHOULD BE NEARLY STRADDLING THE INTERSTATE 35 CORRIDOR...WHICH ESSENTIALLY MEANS THE THREAT FOR STRONG TO SEVERE STORMS WILL LIE FROM THE TWIN CITIES TO SOUTH CENTRAL MN...EASTWARD ACROSS WEST CENTRAL WI. THE CONVERGENCE ALONG THE FRONT LOCALLY IS NOT FANTASTIC...BUT PROGGED INSTABILITY /MUCAPES OF 2500-3000 J/KG AND LIFTED INDICES AROUND -4C/ AND BULK SHEAR VALUES AROUND 35 KTS COULD BE SUFFICIENT TO GENERATE A FEW FEISTIER STORMS PRIMARILY ALONG/EAST OF INTERSTATE 35. CONVECTION SHIFTS OUT OF THE AREA FAIRLY SWIFTLY THIS EVENING AS THE FRONT EXITS...WITH CLEARING SKIES AFTER MIDNIGHT. HIGH TEMPERATURES TODAY SHOULD RANGE FROM THE UPPER 70S /WEST CENTRAL MN/...TO THE MID AND UPPER 80S ACROSS THE REMAINDER OF THE AREA. IT WILL ALSO BE A BIT BREEZY IN THE WAKE OF THE FRONT...WITH GUSTS TO AROUND 25 MPH THIS AFTERNOON AND EARLY EVENING. LOWS TONIGHT WILL BE RIGHT AROUND LATE JULY NORMS IN THE UPPER 50S AND LOWER 60S. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 359 AM CDT MON JUL 22 2013 MAIN THEMES FOR THE EXTENDED IS THAT ONE...IT LOOKS INCREDIBLY PLEASANT FOR JULY...WITH TEMPERATURES MAINLY BELOW NORMAL AND DEWPS IN THE 50S WITH OCCASIONAL 60S. THE OTHER THEME IS A LONG LINE OF CHANCE/SLIGHT CHANCE POPS FOR THE SECOND HALF OF THIS WEEK AS A BOUNDARY GETS HUNG UP BENEATH A SEASONABLY STRONG NW FLOW ALOFT. THE DOMINATE UPPER AIR FEATURE THROUGH THE LONG TERM WILL BE A SEASONABLY STRONG CLOSED UPPER LOW THAT WILL BE OSCILLATING IN STRENGTH/POSITION ACROSS ERN CANADA AS UPPER RIDGING REMAINS ACROSS THE ROCKIES. THIS PATTERN WILL KEEP US IN NW FLOW AND THE PLEASANT CONDITIONS. GIVEN THE MODEST MID AND UPPER LEVEL JETTING THAT WILL BE OVERHEAD MUCH OF THE TIME...WILL SEE SEVERAL WEAK DISTURBANCES RIPPLE THROUGH THE FLOW...BUT THERE IS MUCH DISAGREEMENT AMONGST MODELS ON TIMING/STRENGTH/PLACEMENT OF ALL THESE WAVES...WHICH IS WHY THE FORECAST IS LITTERED WITH LOW POPS FROM WEDNESDAY THROUGH SATURDAY. AT THE SFC...HIGH PRESSURE WILL DOMINATE THRU TUESDAY IN THE WAKE OF TODAYS FRONT. ANOTHER WEAK AND RATHER DIFFUSE FRONT WILL WORK INTO THE AREA ON WEDNESDAY...WHEN IT RUNS INTO THE HIGH PRESSURE AND MEDIUM RANGE MODELS QUICKLY DIVERGE ON WHERE IT GOES FROM THERE. THE GEM IS THE MOST AGGRESSIVE WITH MOVING IT OUT ON THURSDAY...THE ECMWF HAS PICKED FRIDAY...AND THE GFS WAITS UNTIL SATURDAY TO FINALLY START PUSHING IT SOUTH OF MN. THIS TIMING DIFFERENCE IS KEYED TO HOW QUICKLY EACH MODEL DEEPENS AN H5 LOW NORTH OF LAKE SUPERIOR AT THE END OF THE WEEK. AS YOU CAN IMAGINE...THE GEM IS THE DEEPEST/MOST AGGRESSIVE WITH THIS...WHILE THE GFS IS THE SLOWEST OF THE BUNCH. FOR PRECIP POTENTIAL THIS WEEK...IT IS EASIER TO FIND NEGATIVES THAN IT IS POSITIVES. THE BIGGEST ISSUE DURING THE LONG TERM IS LLJ FORCING AND CONVERGENCE ALONG THE BOUNDARY LOOK WEAK...RESULTING IN A LOW CONFIDENCE POP FORECAST. BEST CHANCES FOR STORMS THOUGH LOOK TO BE WEDNESDAY/WEDNESDAY NIGHT AS BOUNDARY INITIALLY SETTLES IN...THEN AGAIN FRIDAY/FRIDAY NIGHT...OR WHENEVER IT GETS KICKED OUT. GIVEN THE WEAK LOW LEVEL FORCING...THE SEVERE THREAT LOOKS MINIMAL...AND WITH NW FLOW ALOFT...PWATS NEVER LOOK TO STRAY TOO FAR ABOVE THE NORMAL FOR JULY /1.2-1.3 INCHES/...SO NOT SEEING THE POTENTIAL FOR COPIOUS AMOUNTS OF RAINFALL EITHER. ABOUT THE ONLY POSITIVE FOR THIS WEEK IS THAT POOLING OF MOISTURE ALONG THE BOUNDARY WILL PROMOTE THE DEVELOPMENT OF A COUPLE THOUSAND J/KG OF MUCAPE TO WORK WITH MOST AFTERNOONS...WHICH WOULD SUPPORT THE IDEA OF SCT STORMS UNTIL THE BOUNDARY IS KICKED SOUTH OF HERE. ON THE TEMPERATURE FRONT...NOT ONLY ARE THERE CURRENTLY NO SIGNS OF WARM AIR THIS WEEK...BUT FOR THE REST OF THE MONTH...THE GFS AND ECMWF KEEP H85 TEMPS BELOW 20C. IF THAT ENDS UP HAPPENING...THEN WE MAY HAVE VERY WELL SEEN OUR LAST 90S OF THE MONTH BACK ON THE 18TH. IT IS EVEN LOOKING LIKE THERE WILL BE THE POTENTIAL FOR LOWS WEDNESDAY MORNING INTO THE 40S ACROSS PARTS OF WRN WI. IN FACT...THE 22.00 MAV GUIDANCE IS CURRENTLY FORECASTING TEMPERATURES NEAR RECORD LOWS OUT IN WRN WI FOR WEDNESDAY MORNING /48 FROM 1971 IS THE MARK TO BEAT AT EAU/. IF WE CAN MIX DEWPOINTS OUT AS MUCH AS THE MIXED LAYER DEWPS FROM THE NAM/GFS INDICATE FOR TUESDAY...THEN WE MAY BE ABLE MAKE A RUN AT THAT RECORD. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 617 AM CDT MON JUL 22 2013 THERE SHOULD BE AN OVERALL LULL IN CONVECTIVE ACTIVITY FOR THE NEXT SEVERAL HOURS...WITH REDEVELOPMENT EXPECTED BY 16Z AS DIURNAL DESTABILIZATION OCCURS IN CONJUNCTION WITH THE ADVANCING COLD FRONT. SHOWERS AND THUNDERSTORMS SHOULD MOSTLY BE CONFINED TO FAR EAST CENTRAL MN AND WEST CENTRAL WI...WITH KMSP BEING ON THE WESTERN EDGE OF THE REDEVELOPMENT AREA. HAVE INCLUDED VCTS AT KMSP...TEMPOS AT WI SITES /KRNH AND KEAU/...AND DRY ELSEWHERE FOR THIS AFTERNOON. LOW-END VFR TO HIGH-END MVFR CONDITIONS POSSIBLE WITH ANY CONVECTION. SOUTH/SOUTHWEST WINDS AHEAD OF THE FRONT...VEERING TO NORTHWEST AND GUSTING TO BETWEEN 20 AND 25 /KNOTS/ WITH THE FROPA. CLEARING SKIES THIS EVENING...WITH VFR CONDITIONS THROUGH THE REMAINDER OF THE PERIOD. KMSP... COULD SEE A PERIOD OF SCT MVFR CIGS AS STRATUS OVER SERN MN CREEPS NORTH THIS MORNING...BUT EXPECT THAT TO BREAK UP AS DRIER AIR IS ENCOUNTERED. OTHERWISE...THERE/S A LOW CHANCE FOR THUNDERSTORM REDEVELOPMENT DURING THE LATE MORNING AND EARLY AFTERNOON AS THE COLD FRONT PASSES. HOWEVER...COVERAGE IS EXPECTED TO BE SPOTTY WITH HIGHER CHANCES TO THE EAST OF KMSP...SO HAVE ONLY INCLUDED A VCTS AT THIS POINT. SOUTH/SOUTHWEST WINDS THROUGH THE MORNING AHEAD OF THE FRONT...THEN SHIFTING TO THE NORTHWEST AND GUSTING TO AROUND OR JUST OVER 20 KTS THIS AFTERNOON BEHIND THE FRONT. /OUTLOOK FOR KMSP/ TUE...VFR. WINDS N 5 TO 10 KT. WED...VFR. MVFR WITH A CHANCE OF SHRA/TSRA LATE NIGHT. WINDS S 5 KT. THU...CHC SHRA/TSRA. VFR OUTSIDE OF SHRA/TSRA. WINDS WSW 5 KT. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...LS LONG TERM...MPG AVIATION...LS
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
401 AM CDT MON JUL 22 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 359 AM CDT MON JUL 22 2013 EARLY MORNING WATER VAPOR IMAGERY FEATURES A WELL-DEFINED SHORTWAVE TROUGH OVER SOUTHEASTERN MANITOBA AND NORTHWESTERN ONTARIO...WHILE SURFACE ANALYSIS ILLUSTRATES THE ASSOCIATED COLD FRONT STRETCHING FROM NORTHWESTERN MN ACROSS THE EASTERN DAKOTAS. SHOWERS AND THUNDERSTORMS HAVE DEVELOPED AS FAR SOUTH AS WEST CENTRAL MN OVERNIGHT IN RESPONSE TO MODEST LOW LEVEL WARM AIR/MOISTURE ADVECTION AHEAD OF THE TROUGH. THE 22.06Z RAP 925-850MB MOISTURE TRANSPORT MAGNITUDE CORRELATES WELL WITH THE CURRENT COVERAGE/LOCATION OF CONVECTION ON RADAR...WHICH GRADUALLY SHIFTS SOUTHEAST ACROSS THE FORECAST AREA DURING THE MORNING HOURS. THE ACTIVITY WANES AFTER 14-15Z WITH THE VEERING OF THE LLJ...BUT NOT BEFORE REACHING THE TWIN CITIES. THIS SCENARIO IS SUPPORTED BY THE 22.03Z HOPWRF REFLECTIVITY FORECAST...WHICH BRINGS DEINTENSIFYING SHOWERS INTO EAST CENTRAL MN BETWEEN 11Z AND 15Z THIS MORNING. THERE SHOULD THEN BE A BIT OF A LULL IN THE ACTIVITY...UNTIL DIURNAL WARMING TRIGGERS THUNDERSTORM RE-DEVELOPMENT ALONG THE FRONT DURING THE AFTERNOON. BY 18Z...THE BOUNDARY SHOULD BE NEARLY STRADDLING THE INTERSTATE 35 CORRIDOR...WHICH ESSENTIALLY MEANS THE THREAT FOR STRONG TO SEVERE STORMS WILL LIE FROM THE TWIN CITIES TO SOUTH CENTRAL MN...EASTWARD ACROSS WEST CENTRAL WI. THE CONVERGENCE ALONG THE FRONT LOCALLY IS NOT FANTASTIC...BUT PROGGED INSTABILITY /MUCAPES OF 2500-3000 J/KG AND LIFTED INDICES AROUND -4C/ AND BULK SHEAR VALUES AROUND 35 KTS COULD BE SUFFICIENT TO GENERATE A FEW FEISTIER STORMS PRIMARILY ALONG/EAST OF INTERSTATE 35. CONVECTION SHIFTS OUT OF THE AREA FAIRLY SWIFTLY THIS EVENING AS THE FRONT EXITS...WITH CLEARING SKIES AFTER MIDNIGHT. HIGH TEMPERATURES TODAY SHOULD RANGE FROM THE UPPER 70S /WEST CENTRAL MN/...TO THE MID AND UPPER 80S ACROSS THE REMAINDER OF THE AREA. IT WILL ALSO BE A BIT BREEZY IN THE WAKE OF THE FRONT...WITH GUSTS TO AROUND 25 MPH THIS AFTERNOON AND EARLY EVENING. LOWS TONIGHT WILL BE RIGHT AROUND LATE JULY NORMS IN THE UPPER 50S AND LOWER 60S. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 359 AM CDT MON JUL 22 2013 MAIN THEMES FOR THE EXTENDED IS THAT ONE...IT LOOKS INCREDIBLY PLEASANT FOR JULY...WITH TEMPERATURES MAINLY BELOW NORMAL AND DEWPS IN THE 50S WITH OCCASIONAL 60S. THE OTHER THEME IS A LONG LINE OF CHANCE/SLIGHT CHANCE POPS FOR THE SECOND HALF OF THIS WEEK AS A BOUNDARY GETS HUNG UP BENEATH A SEASONABLY STRONG NW FLOW ALOFT. THE DOMINATE UPPER AIR FEATURE THROUGH THE LONG TERM WILL BE A SEASONABLY STRONG CLOSED UPPER LOW THAT WILL BE OSCILLATING IN STRENGTH/POSITION ACROSS ERN CANADA AS UPPER RIDGING REMAINS ACROSS THE ROCKIES. THIS PATTERN WILL KEEP US IN NW FLOW AND THE PLEASANT CONDITIONS. GIVEN THE MODEST MID AND UPPER LEVEL JETTING THAT WILL BE OVERHEAD MUCH OF THE TIME...WILL SEE SEVERAL WEAK DISTURBANCES RIPPLE THROUGH THE FLOW...BUT THERE IS MUCH DISAGREEMENT AMONGST MODELS ON TIMING/STRENGTH/PLACEMENT OF ALL THESE WAVES...WHICH IS WHY THE FORECAST IS LITTERED WITH LOW POPS FROM WEDNESDAY THROUGH SATURDAY. AT THE SFC...HIGH PRESSURE WILL DOMINATE THRU TUESDAY IN THE WAKE OF TODAYS FRONT. ANOTHER WEAK AND RATHER DIFFUSE FRONT WILL WORK INTO THE AREA ON WEDNESDAY...WHEN IT RUNS INTO THE HIGH PRESSURE AND MEDIUM RANGE MODELS QUICKLY DIVERGE ON WHERE IT GOES FROM THERE. THE GEM IS THE MOST AGGRESSIVE WITH MOVING IT OUT ON THURSDAY...THE ECMWF HAS PICKED FRIDAY...AND THE GFS WAITS UNTIL SATURDAY TO FINALLY START PUSHING IT SOUTH OF MN. THIS TIMING DIFFERENCE IS KEYED TO HOW QUICKLY EACH MODEL DEEPENS AN H5 LOW NORTH OF LAKE SUPERIOR AT THE END OF THE WEEK. AS YOU CAN IMAGINE...THE GEM IS THE DEEPEST/MOST AGGRESSIVE WITH THIS...WHILE THE GFS IS THE SLOWEST OF THE BUNCH. FOR PRECIP POTENTIAL THIS WEEK...IT IS EASIER TO FIND NEGATIVES THAN IT IS POSITIVES. THE BIGGEST ISSUE DURING THE LONG TERM IS LLJ FORCING AND CONVERGENCE ALONG THE BOUNDARY LOOK WEAK...RESULTING IN A LOW CONFIDENCE POP FORECAST. BEST CHANCES FOR STORMS THOUGH LOOK TO BE WEDNESDAY/WEDNESDAY NIGHT AS BOUNDARY INITIALLY SETTLES IN...THEN AGAIN FRIDAY/FRIDAY NIGHT...OR WHENEVER IT GETS KICKED OUT. GIVEN THE WEAK LOW LEVEL FORCING...THE SEVERE THREAT LOOKS MINIMAL...AND WITH NW FLOW ALOFT...PWATS NEVER LOOK TO STRAY TOO FAR ABOVE THE NORMAL FOR JULY /1.2-1.3 INCHES/...SO NOT SEEING THE POTENTIAL FOR COPIOUS AMOUNTS OF RAINFALL EITHER. ABOUT THE ONLY POSITIVE FOR THIS WEEK IS THAT POOLING OF MOISTURE ALONG THE BOUNDARY WILL PROMOTE THE DEVELOPMENT OF A COUPLE THOUSAND J/KG OF MUCAPE TO WORK WITH MOST AFTERNOONS...WHICH WOULD SUPPORT THE IDEA OF SCT STORMS UNTIL THE BOUNDARY IS KICKED SOUTH OF HERE. ON THE TEMPERATURE FRONT...NOT ONLY ARE THERE CURRENTLY NO SIGNS OF WARM AIR THIS WEEK...BUT FOR THE REST OF THE MONTH...THE GFS AND ECMWF KEEP H85 TEMPS BELOW 20C. IF THAT ENDS UP HAPPENING...THEN WE MAY HAVE VERY WELL SEEN OUR LAST 90S OF THE MONTH BACK ON THE 18TH. IT IS EVEN LOOKING LIKE THERE WILL BE THE POTENTIAL FOR LOWS WEDNESDAY MORNING INTO THE 40S ACROSS PARTS OF WRN WI. IN FACT...THE 22.00 MAV GUIDANCE IS CURRENTLY FORECASTING TEMPERATURES NEAR RECORD LOWS OUT IN WRN WI FOR WEDNESDAY MORNING /48 FROM 1971 IS THE MARK TO BEAT AT EAU/. IF WE CAN MIX DEWPOINTS OUT AS MUCH AS THE MIXED LAYER DEWPS FROM THE NAM/GFS INDICATE FOR TUESDAY...THEN WE MAY BE ABLE MAKE A RUN AT THAT RECORD. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1152 PM CDT SUN JUL 21 2013 THUNDERSTORMS OVER THE DAKOTAS ARE INDEED WEAKENING AS EXPECTED... BUT A FEW SHOWERS MAY BE IN THE VICINITY OF AXN DURING THE FIRST SEVERAL HOURS OF THE TAF PERIOD. HAVE A HARD TIME SEEING THEM MAKING IT AS FAR EAST AS STC OR AS FAR SOUTH AS RWF. THE FRONT WILL LIKELY BECOME MORE ACTIVE AGAIN LATE MONDAY MORNING OVER ERN MN AND MONDAY AFTERNOON OVER WRN WI. CONTINUED THE PROB30S UNTIL FROPA WITH WINDS VEERING NORTHWEST AND INCREASING WITH GUSTS TO 20 KT UNTIL EARLY EVENING. KMSP...BIGGEST CONCERN CONTINUES TO BE WHETHER THE IFR CIGS OVER WRN WI CAN MAKE IT AS FAR WEST AS MSP EARLY MONDAY. CURRENT INDICATIONS ARE THAT THEY WILL NOT...BUT IT WILL BE CLOSE. CONTINUED SCT MVFR MENTION FOR NOW. /OUTLOOK FOR KMSP/ TUE...VFR. WINDS N 5 TO 10 KT. WED...VFR. MVFR WITH A CHANCE OF SHRA/TSRA LATE NIGHT. WINDS LGT AND VRB. THU...CHC SHRA/TSRA. VFR OUTSIDE OF SHRA/TSRA. WINDS LGT AND VRB. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...LS LONG TERM...MPG AVIATION...BORGHOFF
RELEVANT PORTIONS OF THE PREVIOUS FORECAST DISCUSSION FOLLOW. /DL/

&& .AVIATION...WITH OUTFLOW BOUNDARIES STILL MEANDERING ABOUT THE AREA AND UPPER LEVEL DISTURBANCES REPEATEDLY MOVING ACROSS THE REGION... DECENT CHANCES FOR CONVECTION WILL REMAIN AT SITES THROUGH THE FORECAST PERIOD...PARTICULARLY WEDNESDAY AFTERNOON. VFR CONDITIONS ARE CURRENTLY PREVAILING AT TAF SITES AND WILL CONTINUE THROUGH MUCH OF THE NIGHT. LOW STRATUS COULD AGAIN DEVELOP TOWARDS DAY BREAK WEDNESDAY RESULTING IN A PERIOD OF MVFR CEILINGS. PATCHY FOG IS ALSO POSSIBLE...MAINLY ACROSS EAST AND SOUTHEAST MISSISSIPPI (KMEI AND KHBG)...WHICH COULD LEAD TO A BRIEF PERIOD OF MVFR VISIBILITIES AROUND SUNRISE. WINDS OVERNIGHT WILL REMAIN SOUTHWESTERLY BETWEEN 3-8 KNOTS...BUT BECOME MORE WESTERLY WEDNESDAY AFTERNOON AROUND 10 KNOTS WITH SCATTERED CONVECTION EXPECTED AGAIN FROM LATE-MORNING... THROUGH THE AFTERNOON...AND INTO THE EARLY EVENING HOURS. /19/ && .PREV DISCUSSION... /ISSUED AT 350 PM CDT TUE JUL 23 2013/ THE SURFACE TROUGH WILL PROGRESS SWD ACROSS THE FORECAST AREA WEDNESDAY. AN UPPER WAVE IS ALSO INDICATED ACROSS THE REGION. THE EVOLUTION OF ANYTHING THAT MAY GET GOING TOWARD MORNING WILL EFFECT RAINFALL COVERAGE TOMORROW BUT SCATTERED TO NUMEROUS CONVECTION COVERAGE IS EXPECTED. MAV MOS POPS WILL BE INCREASED SLIGHTLY OVER WRN ZONES TO COVER THE CONVECTION POTENTIAL WITH THE BOUNDARY AND THE WAVE. DRIER AIR IS FORECAST BEHIND THE BOUNDARY...WHICH DROPS INTO SRN ZONES WEDNESDAY EVENING/NIGHT. SCT SHOWERS/TSTMS WILL EXTEND ACROSS SRN ZONES THURSDAY AFTERNOON AS DRIER AIR SEEPS IN FROM THE NORTH. THE LATEST MOS NUMBERS ARE ADVERTISING LOWS IN THE 60S ACROSS MUCH OF THE FORECAST AREA FOR THURSDAY NIGHT IN RESPONSE TO THIS AIR MASS CHANGE. ALSO OF NOTE IS THAT MOS HIGHS HAVE BEEN CUT SLIGHTLY AT MOST LOCATIONS FOR WEDNESDAY AND THURSDAY. /03/ LONG TERM...THE LONG TERM PORTION OF THE FORECAST IS SIMILAR TO THE PREVIOUS AS THE REGION WILL SEE A BRIEF REPRIEVE FROM THE NW FLOW FOR LATE WEEK BEFORE A POTENTIAL RETURN TO THAT SORT OF PATTERN BY THE WEEKEND AND INTO NEXT WEEK. FOR FRI...THANKS TO THE PERSISTENT NW FLOW FROM MID WEEK...THIS PERIOD WILL SEE A WEAK SFC FRONT ENTER THE FORECAST AREA AND LIKELY STALL BEFORE IT PUSHES THROUGH THE AREA. THIS STALLING WILL BE IN PART TO THE S/WV RIDGING DEVELOPING AS A MORE STOUT S/WV MOVES OUT OF THE ROCKIES. THE RESPONSE TO THIS FEATURE WILL BE FOR THE STALLED SFC BOUNDARY TO LIFT BACK NORTH LIKE A WARM FRONT BY FRI THEN BACK INTO THE AREA FOR AROUND SAT AS THE MAIN S/WV AXIS NEAR THE REGION. BY FRI...LOW LEVEL CAPPING LOOKS TO EXIST AND THE BEST LOW LEVEL MOISTURE CONVERGENCE IS SITUATED WELL TO THE W/NW OF THE AREA. DUE TO THIS...LOWERED POPS AND FOCUSED SOME LOW END CHANCES IN THE NW PART OF THE CWA. BY LATE FRI NIGHT INTO SAT/SAT NIGHT...THE MAIN DISTURBANCE LOOKS TO BE PUSHING OUT OF THE PLAINS AND NEAR/INTO THE REGION. BOTH THE GFS/EURO SHOW A STRONG SFC LOW FOR THIS TIME OF YEAR AS THE LOW LEVEL RESPONSE TO THE STOUT UPPER FEATURE. MOISTURE CONVERGENCE AND LIFT LOOK TO COME TOGETHER LATE FRI NIGHT INTO SAT TO SUPPORT THE BEST PRECIP POTENTIAL. THE EURO IS A TAD SLOWER THAN THE GFS...SO I HELD ONTO SOME 20-30% POPS SAT NIGHT DUE TO THE TIMING UNCERTAINTY. THERE COULD BE SOME STRONG/SVR STORMS WITH THIS SAT SYSTEM DUE TO STRONGER FORCING AND ABOVE NORMAL VALUES OF WIND SHEAR. HOWEVER...DUE TO THIS BEING 5 DAYS OUT AND TIMING UNCERTAINTY...WILL NOT MENTION ANY RISKS IN OFFICIAL PRODUCTS. IN THE WAKE OF THIS FEATURE...ANOTHER SFC FRONT LOOKS TO MAKE A PUSH INTO THE FORECAST AREA. THE GFS IS MOST AGGRESSIVE AND PUSHES 60S DEWPTS WELL INTO THE REGION. I`M MORE INCLINED TO FOLLOW THE SLIGHTLY LESS AGGRESSIVE EURO AT THIS TIME. STILL...THERE LOOKS TO BE A PERIOD OF LOWER HUMIDITY AND COOLER TEMPS AS A RESULT OF THE FRONT. BY LATE MON INTO TUE...A NW FLOW PATTERN MAY RETURN RESULTING IN PRECIP CHANCES INCREASING. AS FOR TEMPS...THE GFS CONTINUES TO BE AGGRESSIVE ON HAVING HOT TEMPS AROUND FOR THU-FRI. FEEL THIS IS OVERDONE AND WILL CONTINUE THE TREND OF CUTTING HIGHS EACH OF THOSE DAYS...MORE IN LINE WITH THE EURO. BY SAT-SUN...THE GFS HAS COME IN QUITE A BIT COOLER THAN PREV RUNS THANKS TO THE PRESENCE OF THE SFC LOW AND THEN FRONTAL PASSAGE. FEEL THIS COOLER SOLUTION FITS WELL AND WILL FOLLOW. BY EARLY NEXT WEEK...LOOK FOR MODERATION AND A RETURN TO TYPICAL JULY CONDITIONS. /CME/ && .JAN WATCHES/WARNINGS/ADVISORIES... MS...NONE. LA...NONE. AR...NONE. && $$ DL/19/03/CME
AREA FORECAST DISCUSSION
NWS HASTINGS NE
708 PM CDT TUE JUL 23 2013 .UPDATE... ISSUED AT 708 PM CDT TUE JUL 23 2013 AS OF 00Z KUEX INDICATES DEEP CONVECTION HAS MOVED SOUTH OF OUR CWA CLOSER TO THE I-70 CORRIDOR. IN ADDITION...DEEP CONVECTION OVER THE HIGH PLAINS OF WESTERN NEBRASKA IS MOVING MORE SOUTHERLY AND IF THESE TRENDS CONTINUE...SHOULD MISS OUR CWA TO THE WEST. BARRING ADDITIONAL SHOWER AND THUNDERSTORM DEVELOPMENT TO OUR NORTHWEST THIS EVENING AND TONIGHT...DRY CONDITIONS SHOULD PREVAIL AND AS A RESULT...POPS HAVE BEEN REMOVED FROM THE FORECAST AND ASSOCIATED SEVERE WEATHER WORDING REMOVED FROM THE HWO. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 400 PM CDT TUE JUL 23 2013 THE MAIN FOCUS FOR THIS EVENING/TONIGHT IS ON TSTM POTENTIAL. CONVECTION WAS ONGOING FOR MUCH OF THE DAY TODAY BUT IN THE LAST FEW HOURS THIS ACTIVITY HAS DISSIPATED. THE CAP REMAINS STRONG ACROSS OUR SOUTHERN ZONES WITH THE MAIN BOUNDARY/WARM FRONT ORIENTED ACROSS SOUTHERN KANSAS. THIS BEING SAID...REMNANT OUTFLOW BOUNDARIES/DIFFERENTIAL HEATING BOUNDARIES RESIDE ACROSS OUR CWA WITH THE NORTHERN TWO THIRDS OF OUR CWA REMAINING UNCAPPED. ONE SUCH BOUNDARY FOR OUR CWA IS ORIENTED NEAR THE NEB/KS STATE LINE AND CANNOT RULE OUT STRONG/SEVERE STORMS IN THIS AREA AS BOUNDARY SAGS SOUTH WITH INSTABILITY ON THE ORDER OF 2000 TO 3000 J/KG AND GOOD SHEAR IN OUR NW FLOW REGIME. FARTHER NORTH...A HIT OR MISS SHOWER/STORM CANNOT BE RULED OUT AS SUBTLE SHORTWAVE TROUGHS TRANSLATE SE ACROSS THE INTERIOR CONUS. FARTHER UPSTREAM...NEW STORMS ARE DEVELOPING ACROSS WESTERN SOUTH DAKOTA IN A SIMILAR MANNER AS 24HRS AGO...BUT CONFIDENCE IS NOT HIGH THAT THESE STORMS WILL SUSTAIN INTO THE OVERNIGHT HOURS TO IMPACT OUR REGION...BUT WILL NEED TO MONITOR. THE HRRR TRACKS THIS ACTIVITY TO THE WEST OF OUR CWA. ASIDE FM THE HIT OR MISS STORM POTENTIAL...WE ARE LOOKING AT FAIRLY SEASONAL CONDITIONS OR PERHAPS A FEW DEGREES COOLER THAN NORMAL BOTH TONIGHT AND WEDNESDAY. A SFC RIDGE AXIS WILL BUILD TO THE SOUTHWEST FM THE UPPER MIDWEST AND COOLER AIR WILL BACK IN FM THE NORTHEAST. SFC DPS DROP SEVERAL DEGREES AND OVERNIGHT LOWS SHLD AVERAGE IN THE UPPER 50S TO LOW 60S. MODELS INDICATE SOME POTENTIAL FOR SOME LOW CLOUDS AROUND TONIGHT/EARLY WEDNESDAY...MAINLY IN KS. THERE ARE SOME MODEL DIFFERENCES ON HIGHS FOR WEDNESDAY BUT WITH THE AIRMASS MORE SIMILAR TO TODAY...WILL AIM FOR HIGH TEMPS IN THE MID/UPPER 80S. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 400 PM CDT TUE JUL 23 2013 OVER THE PAST SEVERAL DAYS...MORE AND MORE OF THE CWA HAS GRADUALLY RECEIVED AT LEAST MINIMAL AMOUNTS OF MEANINGFUL MEASURABLE RAIN AFTER A VERY DRY START TO THE MONTH...AND THIS TREND OF VARIOUS...HIT-AND-MISS RAIN CHANCES IN WHICH PARTS OF THE AREA SEE DECENT PRECIPITATION WHILE OTHERS LARGELY MISS OUT IS EXPECTED TO CONTINUE THROUGH THE FORECAST PERIOD. AT THIS TIME...ALL RAIN CHANCES OVER THIS 6-DAY PERIOD HAVE BEEN CAPPED AT NO MORE THAN 30-50 PERCENT...UNTIL/UNLESS CONFIDENCE INCREASES. ALTHOUGH VERY SUBJECT TO CHANGE...THE THURS/THURS NIGHT AND SUN NIGHT/MONDAY TIME FRAMES CURRENTLY CONTAIN THE OVERALL-HIGHEST COVERAGE OF 30+ POPS. REGARDING SEVERE WEATHER PROSPECTS...ITS AGAIN MUCH THE SAME STORY AS ALTHOUGH ITS QUITE POSSIBLE...IF NOT LIKELY...THAT AT LEAST A FEW SEVERE STORMS FLARE UP FROM TIME TO TIME...THERE IS NO DEFINITIVE SETUP OF HEIGHTENED CONCERN EVIDENT AT THIS TIME...AND THUS HAVE REFRAINED FROM SPECIFYING ANY PERIODS IN THE HAZARDOUS WEATHER OUTLOOK. ON A POSITIVE NOTE FOR MOST FOLKS...THERE IS PRETTY HIGH CONFIDENCE IN A CONTINUED SLIGHTLY BELOW NORMAL TEMPERATURE REGIME...WITH HIGHS ON MOST DAYS AVERAGING 3-8 DEGREES BELOW AVERAGE LATE-JULY VALUES. STARTING OFF WEDNESDAY EVENING/NIGHT...SEASONABLY STRONG NORTHWEST FLOW REMAINS IN PLACE OVER THE CENTRAL PLAINS...BETWEEN RIDGING CENTERED OVER THE NV/CA/UT/AZ BORDER AREA...AND A BROAD LONGWAVE TROUGH OVER THE EASTERN CONUS...WHILE A SHORTWAVE TROUGH DIVES SOUTH-SOUTHEAST ACROSS MANITOBA/SASKATCHEWAN. WITHIN THE LOCAL FLOW...A LOW-AMPLITUDE SHORTWAVE TROUGH IS PROGGED TO RIDE EASTWARD ALONG THE KS/NE BORDER OUT OF NORTHEAST CO AS THE NIGHT WEARS ON. ALTHOUGH INSTABILITY APPEARS PRETTY MINIMAL LOCALLY...HAVE EXPANDED SLIGHT CHANCES FOR STORMS ACROSS MUCH OF THE WESTERN HALF OF THE CWA POST-MIDNIGHT...WHILE LEAVING THE EVENING HOURS DRY...AT LEAST FOR NOW. MADE LITTLE CHANGE OT LOW TEMPS...WITH MID 60S MOST AREAS. THURSDAY/THURSDAY NIGHT...POP-WISE MADE LITTLE CHANGE FROM PREVIOUS FORECAST WITH A BROAD COVERAGE OF 30 POPS AND SOME 40S- 50S MAINLY FOCUSED IN SOUTHERN ZONES. ALOFT...ITS THE SAME OLD THEME...WITH SUBTLE EMBEDDED SHORTWAVE TROUGHS WORKING OVER OR NEAR THE CWA IN NORTHWEST FLOW...WHILE A STRONGER SHORTWAVE TROUGH DROPS OUT OF CANADA INTO THE NORTHERN MN AREA. NOT SURPRISINGLY...MODEL QPF FIELDS ARE OVER THE PLACE...WITH THE ECMWF HITTING THE DAYTIME HOURS A LITTLE HARDER AND THE GFS THE NIGHT. TEMP-WISE...WITH A RETURN TO MORE SOUTHERLY WINDS...NUDGED UP HIGH TEMPS A LITTLE FROM PREVIOUS PER MET/MAV GUIDANCE BLEND...BUT STILL ONLY MID 80S IN MOST AREAS. FRIDAY/FRIDAY NIGHT...CONTINUED 20-30 POPS CWA-WIDE THIS ENTIRE TIME...ALTHOUGH LARGE SCALE SUPPORT WANES A BIT FRIDAY NIGHT AS THE AFOREMENTIONED GREAT LAKES REGION SHORTWAVE TROUGH CLOSES OFF AND STARTS TO SLOWLY EDGE FARTHER EAST. IN THE WAKE OF A PASSING COLD FRONT AND RETURN TO NORTHEAST BREEZES...HAVE HIGHS BACK DOWN IN THE LOW 80S MOST NEB ZONES...AND MID 80S IN KS. SATURDAY/SATURDAY NIGHT...CAME VERY CLOSE TO LEAVING THE CWA VOID OF THUNDERSTORM MENTION DURING THE DAY PER PREVIOUS FORECAST...BUT WENT AHEAD AND BROUGHT SOME SLIGHT POPS BACK INTO PARTS OF THE SOUTHWEST 1/2 MAINLY PER THE 12Z ECMWF. SATURDAY NIGHT...HINTS OF A SUBTLE SHORTWAVE TROUGH CONTINUE TO SUPPORT SLIGHT POPS AREA- WIDE. HIGH TEMPS SATURDAY AGAIN LOW-MID 80S. SUNDAY/SUNDAY NIGHT...THE LARGE-SCALE FLOW STARTS TO TURN LEGITIMATELY MORE ZONAL VERSUS NORTHWESTERLY...IN THE WAKE OF THE GREAT LAKES CLOSED LOW LIFTING BACK NORTHEAST INTO CANADA...BUT THE TRAIN OF LOW AMPLITUDE DISTURBANCES INTO THE CENTRAL PLAINS CONTINUES...AND HAVE SLIGHT POPS IN NEARLY ALL AREAS DURING THE DAY...FOLLOWED BY 30-40 POPS SUNDAY NIGHT. MONDAY/MONDAY NIGHT...CONTINUED QUASI-ZONAL FLOW WITH EMBEDDED DISTURBANCES...AND HAVE AT LEAST SLIGHT POPS THROUGHOUT THIS 24 HOURS ALL AREAS...AND HIGHER VALUES CURRENTLY FOCUSED DURING THE DAY. TEMP-WISE...LOW 80S NORTHEAST TO NEAR 90 SOUTHWEST. TUESDAY...HAVE KEPT IT DRY FOR NOW...BUT ITS NO GUARANTEE TO STAY THAT WAY...AS THERE IS OVERALL LITTLE CHANGE IN THE PATTERN. POSSIBLY IN RESPONSE TO CLIMATOLOGY CARRYING MORE WEIGHT WITH MODEL GUIDANCE AT THIS TIME RANGE...HIGHS TUESDAY ARE PRELIMINARILY ADVERTISED TO BE A TOUCH WARMER THAN PREVIOUS DAYS...WITH MID 80S NORTHEAST TO LOWER 90S SOUTHWEST. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING) ISSUED AT 609 PM CDT TUE JUL 23 2013 VFR CONDITIONS FORECAST THROUGH THE NEXT 24 HOURS. THE SURFACE WIND WILL REMAIN FROM THE NORTHEAST AT AROUND 08KTS TO START THE TAF PERIOD...BUT BECOME LIGHT AND VARIABLE 03Z ONWARD. LITTLE IN THE WAY CLOUD COVER IS CURRENTLY EXPECTED. NEAR-ZERO LOW LEVEL DEWPOINT DEPRESSIONS COULD PROMOTE ISOLATED FOG ACROSS PORTIONS OF THE AREA AROUND DAYBREAK WEDNESDAY...BUT AT THIS TIME VISIBILITY RESTRICTION IS NOT EXPECTED TO BE SIGNIFICANT AND NO FOG MENTION/VISIBILITY RESTRICTION WAS PRESENTED TO THE TAF AS A RESULT. FINALLY...AT THIS TIME IT DOES NOT APPEAR SHOWER AND THUNDERSTORM ACTIVITY WILL IMPACT GRI THROUGH THE NEXT 24 HOURS AND AS A RESULT...NO SUCH ACTIVITY WAS INTRODUCED INTO THE TAF. THAT BEING SAID...THERE IS A CLUSTER OF SHOWER AND THUNDERSTORM ACTIVITY OVER NORTHWESTERN NEBRASKA...MOVING SOUTH/SOUTHEAST. THIS ACTIVITY WILL NEED TO BE MONITORED THROUGH THE NEXT 6-12 HOURS FOR PATH AND PERSISTENCE. SHOULD IT BECOME APPARENT THIS SHOWER AND THUNDERSTORM ACTIVITY WILL IMPACT GRI...SUCH CONDITIONS WILL BE INTRODUCED INTO THE TAF AT THAT TIME. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ 708 PM UPDATE...BRYANT SHORT TERM...FAY LONG TERM...PFANNKUCH AVIATION...BRYANT
AREA FORECAST DISCUSSION
NWS HASTINGS NE
609 PM CDT TUE JUL 23 2013 .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 400 PM CDT TUE JUL 23 2013 THE MAIN FOCUS FOR THIS EVENING/TONIGHT IS ON TSTM POTENTIAL. CONVECTION WAS ONGOING FOR MUCH OF THE DAY TODAY BUT IN THE LAST FEW HOURS THIS ACTIVITY HAS DISSIPATED. THE CAP REMAINS STRONG ACROSS OUR SOUTHERN ZONES WITH THE MAIN BOUNDARY/WARM FRONT ORIENTED ACROSS SOUTHERN KANSAS. THIS BEING SAID...REMNANT OUTFLOW BOUNDARIES/DIFFERENTIAL HEATING BOUNDARIES RESIDE ACROSS OUR CWA WITH THE NORTHERN TWO THIRDS OF OUR CWA REMAINING UNCAPPED. ONE SUCH BOUNDARY FOR OUR CWA IS ORIENTED NEAR THE NEB/KS STATE LINE AND CANNOT RULE OUT STRONG/SEVERE STORMS IN THIS AREA AS BOUNDARY SAGS SOUTH WITH INSTABILITY ON THE ORDER OF 2000 TO 3000 J/KG AND GOOD SHEAR IN OUR NW FLOW REGIME. FARTHER NORTH...A HIT OR MISS SHOWER/STORM CANNOT BE RULED OUT AS SUBTLE SHORTWAVE TROUGHS TRANSLATE SE ACROSS THE INTERIOR CONUS. FARTHER UPSTREAM...NEW STORMS ARE DEVELOPING ACROSS WESTERN SOUTH DAKOTA IN A SIMILAR MANNER AS 24HRS AGO...BUT CONFIDENCE IS NOT HIGH THAT THESE STORMS WILL SUSTAIN INTO THE OVERNIGHT HOURS TO IMPACT OUR REGION...BUT WILL NEED TO MONITOR. THE HRRR TRACKS THIS ACTIVITY TO THE WEST OF OUR CWA. ASIDE FM THE HIT OR MISS STORM POTENTIAL...WE ARE LOOKING AT FAIRLY SEASONAL CONDITIONS OR PERHAPS A FEW DEGREES COOLER THAN NORMAL BOTH TONIGHT AND WEDNESDAY. A SFC RIDGE AXIS WILL BUILD TO THE SOUTHWEST FM THE UPPER MIDWEST AND COOLER AIR WILL BACK IN FM THE NORTHEAST. SFC DPS DROP SEVERAL DEGREES AND OVERNIGHT LOWS SHLD AVERAGE IN THE UPPER 50S TO LOW 60S. MODELS INDICATE SOME POTENTIAL FOR SOME LOW CLOUDS AROUND TONIGHT/EARLY WEDNESDAY...MAINLY IN KS. THERE ARE SOME MODEL DIFFERENCES ON HIGHS FOR WEDNESDAY BUT WITH THE AIRMASS MORE SIMILAR TO TODAY...WILL AIM FOR HIGH TEMPS IN THE MID/UPPER 80S. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 400 PM CDT TUE JUL 23 2013 OVER THE PAST SEVERAL DAYS...MORE AND MORE OF THE CWA HAS GRADUALLY RECEIVED AT LEAST MINIMAL AMOUNTS OF MEANINGFUL MEASURABLE RAIN AFTER A VERY DRY START TO THE MONTH...AND THIS TREND OF VARIOUS...HIT-AND-MISS RAIN CHANCES IN WHICH PARTS OF THE AREA SEE DECENT PRECIPITATION WHILE OTHERS LARGELY MISS OUT IS EXPECTED TO CONTINUE THROUGH THE FORECAST PERIOD. AT THIS TIME...ALL RAIN CHANCES OVER THIS 6-DAY PERIOD HAVE BEEN CAPPED AT NO MORE THAN 30-50 PERCENT...UNTIL/UNLESS CONFIDENCE INCREASES. ALTHOUGH VERY SUBJECT TO CHANGE...THE THURS/THURS NIGHT AND SUN NIGHT/MONDAY TIME FRAMES CURRENTLY CONTAIN THE OVERALL-HIGHEST COVERAGE OF 30+ POPS. REGARDING SEVERE WEATHER PROSPECTS...ITS AGAIN MUCH THE SAME STORY AS ALTHOUGH ITS QUITE POSSIBLE...IF NOT LIKELY...THAT AT LEAST A FEW SEVERE STORMS FLARE UP FROM TIME TO TIME...THERE IS NO DEFINITIVE SETUP OF HEIGHTENED CONCERN EVIDENT AT THIS TIME...AND THUS HAVE REFRAINED FROM SPECIFYING ANY PERIODS IN THE HAZARDOUS WEATHER OUTLOOK. ON A POSITIVE NOTE FOR MOST FOLKS...THERE IS PRETTY HIGH CONFIDENCE IN A CONTINUED SLIGHTLY BELOW NORMAL TEMPERATURE REGIME...WITH HIGHS ON MOST DAYS AVERAGING 3-8 DEGREES BELOW AVERAGE LATE-JULY VALUES. STARTING OFF WEDNESDAY EVENING/NIGHT...SEASONABLY STRONG NORTHWEST FLOW REMAINS IN PLACE OVER THE CENTRAL PLAINS...BETWEEN RIDGING CENTERED OVER THE NV/CA/UT/AZ BORDER AREA...AND A BROAD LONGWAVE TROUGH OVER THE EASTERN CONUS...WHILE A SHORTWAVE TROUGH DIVES SOUTH-SOUTHEAST ACROSS MANITOBA/SASKATCHEWAN. WITHIN THE LOCAL FLOW...A LOW-AMPLITUDE SHORTWAVE TROUGH IS PROGGED TO RIDE EASTWARD ALONG THE KS/NE BORDER OUT OF NORTHEAST CO AS THE NIGHT WEARS ON. ALTHOUGH INSTABILITY APPEARS PRETTY MINIMAL LOCALLY...HAVE EXPANDED SLIGHT CHANCES FOR STORMS ACROSS MUCH OF THE WESTERN HALF OF THE CWA POST-MIDNIGHT...WHILE LEAVING THE EVENING HOURS DRY...AT LEAST FOR NOW. MADE LITTLE CHANGE OT LOW TEMPS...WITH MID 60S MOST AREAS. THURSDAY/THURSDAY NIGHT...POP-WISE MADE LITTLE CHANGE FROM PREVIOUS FORECAST WITH A BROAD COVERAGE OF 30 POPS AND SOME 40S- 50S MAINLY FOCUSED IN SOUTHERN ZONES. ALOFT...ITS THE SAME OLD THEME...WITH SUBTLE EMBEDDED SHORTWAVE TROUGHS WORKING OVER OR NEAR THE CWA IN NORTHWEST FLOW...WHILE A STRONGER SHORTWAVE TROUGH DROPS OUT OF CANADA INTO THE NORTHERN MN AREA. NOT SURPRISINGLY...MODEL QPF FIELDS ARE OVER THE PLACE...WITH THE ECMWF HITTING THE DAYTIME HOURS A LITTLE HARDER AND THE GFS THE NIGHT. TEMP-WISE...WITH A RETURN TO MORE SOUTHERLY WINDS...NUDGED UP HIGH TEMPS A LITTLE FROM PREVIOUS PER MET/MAV GUIDANCE BLEND...BUT STILL ONLY MID 80S IN MOST AREAS. FRIDAY/FRIDAY NIGHT...CONTINUED 20-30 POPS CWA-WIDE THIS ENTIRE TIME...ALTHOUGH LARGE SCALE SUPPORT WANES A BIT FRIDAY NIGHT AS THE AFOREMENTIONED GREAT LAKES REGION SHORTWAVE TROUGH CLOSES OFF AND STARTS TO SLOWLY EDGE FARTHER EAST. IN THE WAKE OF A PASSING COLD FRONT AND RETURN TO NORTHEAST BREEZES...HAVE HIGHS BACK DOWN IN THE LOW 80S MOST NEB ZONES...AND MID 80S IN KS. SATURDAY/SATURDAY NIGHT...CAME VERY CLOSE TO LEAVING THE CWA VOID OF THUNDERSTORM MENTION DURING THE DAY PER PREVIOUS FORECAST...BUT WENT AHEAD AND BROUGHT SOME SLIGHT POPS BACK INTO PARTS OF THE SOUTHWEST 1/2 MAINLY PER THE 12Z ECMWF. SATURDAY NIGHT...HINTS OF A SUBTLE SHORTWAVE TROUGH CONTINUE TO SUPPORT SLIGHT POPS AREA- WIDE. HIGH TEMPS SATURDAY AGAIN LOW-MID 80S. SUNDAY/SUNDAY NIGHT...THE LARGE-SCALE FLOW STARTS TO TURN LEGITIMATELY MORE ZONAL VERSUS NORTHWESTERLY...IN THE WAKE OF THE GREAT LAKES CLOSED LOW LIFTING BACK NORTHEAST INTO CANADA...BUT THE TRAIN OF LOW AMPLITUDE DISTURBANCES INTO THE CENTRAL PLAINS CONTINUES...AND HAVE SLIGHT POPS IN NEARLY ALL AREAS DURING THE DAY...FOLLOWED BY 30-40 POPS SUNDAY NIGHT. MONDAY/MONDAY NIGHT...CONTINUED QUASI-ZONAL FLOW WITH EMBEDDED DISTURBANCES...AND HAVE AT LEAST SLIGHT POPS THROUGHOUT THIS 24 HOURS ALL AREAS...AND HIGHER VALUES CURRENTLY FOCUSED DURING THE DAY. TEMP-WISE...LOW 80S NORTHEAST TO NEAR 90 SOUTHWEST. TUESDAY...HAVE KEPT IT DRY FOR NOW...BUT ITS NO GUARANTEE TO STAY THAT WAY...AS THERE IS OVERALL LITTLE CHANGE IN THE PATTERN. POSSIBLY IN RESPONSE TO CLIMATOLOGY CARRYING MORE WEIGHT WITH MODEL GUIDANCE AT THIS TIME RANGE...HIGHS TUESDAY ARE PRELIMINARILY ADVERTISED TO BE A TOUCH WARMER THAN PREVIOUS DAYS...WITH MID 80S NORTHEAST TO LOWER 90S SOUTHWEST. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING) ISSUED AT 609 PM CDT TUE JUL 23 2013 VFR CONDITIONS FORECAST THROUGH THE NEXT 24 HOURS. THE SURFACE WIND WILL REMAIN FROM THE NORTHEAST AT AROUND 08KTS TO START THE TAF PERIOD...BUT BECOME LIGHT AND VARIABLE 03Z ONWARD. LITTLE IN THE WAY CLOUD COVER IS CURRENTLY EXPECTED. NEAR-ZERO LOW LEVEL DEWPOINT DEPRESSIONS COULD PROMOTE ISOLATED FOG ACROSS PORTIONS OF THE AREA AROUND DAYBREAK WEDNESDAY...BUT AT THIS TIME VISIBILITY RESTRICTION IS NOT EXPECTED TO BE SIGNIFICANT AND NO FOG MENTION/VISIBILITY RESTRICTION WAS PRESENTED TO THE TAF AS A RESULT. FINALLY...AT THIS TIME IT DOES NOT APPEAR SHOWER AND THUNDERSTORM ACTIVITY WILL IMPACT GRI THROUGH THE NEXT 24 HOURS AND AS A RESULT...NO SUCH ACTIVITY WAS INTRODUCED INTO THE TAF. THAT BEING SAID...THERE IS A CLUSTER OF SHOWER AND THUNDERSTORM ACTIVITY OVER NORTHWESTERN NEBRASKA...MOVING SOUTH/SOUTHEAST. THIS ACTIVITY WILL NEED TO BE MONITORED THROUGH THE NEXT 6-12 HOURS FOR PATH AND PERSISTENCE. SHOULD IT BECOME APPARENT THIS SHOWER AND THUNDERSTORM ACTIVITY WILL IMPACT GRI...SUCH CONDITIONS WILL BE INTRODUCED INTO THE TAF AT THAT TIME. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM...FAY LONG TERM...PFANNKUCH AVIATION...BRYANT
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1239 PM CDT MON JUL 22 2013 .UPDATE... ISSUED AT 911 AM CDT MON JUL 22 2013 FIRST FORECAST UPDATE OF THE DAY HAS BEEN SENT. IN SHORT...ANOTHER TRICKY DAY/EVENING OF THUNDERSTORM CHANCES AWAITS THE LOCAL AREA. ESSENTIALLY...THE ONLY NOTABLE CHANGE FROM PREVIOUS FORECAST SO FAR WAS TO TRIM CENTRAL/NORTHEAST PORTIONS OF THE CWA FROM ANY THUNDERSTORM MENTION THIS MORNING...WHILE LEAVING MORNING CHANCES INTACT IN KS ZONES...AND MAINLY WEST OF A GOTHENBURG-ALMA LINE IN NEBRASKA TO ACCOUNT FOR THE FAIRLY PERSISTENT NARROW NORTHWEST- SOUTHEAST AXIS OF CONVECTION PRIMARILY AFFECTING FURNAS COUNTY AT THIS TIME. OTHER THAN MAYBE SOME SMALL HAIL...NOT EXPECTING A MORNING SEVERE THREAT. FOR THIS AFTERNOON...ITS HARD TO ARGUE WITH THE SPC SLIGHT RISK FOR ROUGHLY THE SOUTHEAST 2/3 OF THE CWA...ALTHOUGH ITS TOUGH TO SAY WHETHER WE MIGHT ONLY GET 1 OR 2 ISOLATED STRONG-SEVERE STORMS...OR POTENTIALLY MORE SCATTERED COVERAGE. EITHER WAY...THE PRIMARY FORCING MECHANISM ALOFT LOOKS TO BE A FAIRLY SUBTLE SHORTWAVE TROUGH DRIFTING EAST-SOUTHEAST OUT OF WYOMING...WHILE AT THE SURFACE A FAIRLY WEAK COLD FRONT WILL SINK SOUTHWARD INTO PARTS OF THE CWA AS THE DAY WEARS ON...PROVIDING AT LEAST LIMITED LOW-LEVEL CONVERGENCE. THE LATEST RAP FORECAST VALID FOR 21Z/4PM PAINTS 1000-2500 J/KG OF 0-1KM MLCAPE ACROSS MOST OF THE CWA...HIGHEST IN THE SOUTH...IN THE PRESENCE OF DECENT 0-6KM DEEP LAYER SHEAR OF 35-40KT...SO CERTAINLY A THREAT FOR SOME SOUTHEAST-MOVING STRONG TO SEVERE STORMS AND POTENTIALLY SUPERCELLS EXISTS...ALTHOUGH WORKING AGAINST STORM FORMATION APPEARS TO BE AT LEAST A WEAK CAP EVIDENT ON FORECAST SOUNDINGS AROUND 700-650 MILLIBARS...SO ITS ALSO NOT OUT OF THE QUESTION THAT OUR LOCAL AREA COULD LARGELY STEER CLEAR OF AN AFTERNOON/EVENING STORM THREAT...WITH BETTER CHANCES POTENTIALLY FOCUSING JUST TO OUR SOUTH/EAST. EVEN THOUGH THE GREATEST SEVERE THREAT WOULD THEORETICALLY FOCUS ACROSS SOUTHERN PORTIONS OF OUR AREA...HAVE PUT AT LEAST A SLIGHT CHANCE OF STORMS EVEN IN FAR NORTHERN COUNTIES FOR AT LEAST A FEW HOURS THIS AFTERNOON. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 349 AM CDT MON JUL 22 2013 THE CHALLENGING UPPER LEVEL NORTHWEST FLOW PATTERN WILL PERSIST THROUGH THE PERIOD. A SFC AREA OF LOW PRESSURE OVER EASTERN COLORADO/WESTERN KANSAS WILL SAG SOUTH TODAY DRAGGING A SFC TROUGH SOUTH THROUGH OUR FORECAST AREA. THE WIND AHEAD OF THE TROUGH WILL GENERALLY BE OUT OF THE SOUTH TO SOUTHEAST...WHILE AN EAST TO NORTHEAST WIND CAN BE EXPECTED BEHIND THE TROUGH AXIS. THIS WIND SHIFT BOUNDARY SHOULD BE LOCATED NEAR THE NEBRASKA/KANSAS BOARDER BY MID AFTERNOON. HIGH TEMPERATURES WILL BE THE HOTTEST SOUTH OF THE FRONT ACROSS NORTHERN KANSAS WHERE HIGHS SHOULD BE IN THE UPPER 90S AND MAY APPROACH 100. GENERALLY LOW TO MID 90S ARE EXPECTED FURTHER NORTH ACROSS NEBRASKA. THE WIND ON BOTH SIDES OF THE TROUGH WILL BE RATHER LIGHT AND EVEN LIGHT AND VARIABLE NEAR THE BOUNDARY MAKING FOR AN UNCOMFORTABLE HEAT WITHOUT MUCH AIR FLOW. THUNDERSTORMS ARE ONGOING EARLY THIS MORNING ACROSS PORTIONS OF DAWSON AND GOSPER COUNTIES. EXPECT THIS CLUSTER OF THUNDERSTORMS WILL CONTINUE TO TRACK TO THE SOUTHEAST UNTIL AT LEAST DAWN AND MAY POTENTIALLY SURVIVE THROUGH MID MORNING IMPACTING OUR FAR SOUTHWESTERN COUNTIES INCLUDING PORTIONS OF NORTH CENTRAL KANSAS TO THE WEST OF HIGHWAY 281. FORECAST MODELS CONTINUE TO STRUGGLE WITH PRECIPITATION CHANCES TODAY INTO TONIGHT LEADING TO CONTINUED LOW CONFIDENCE IN PRECIPITATION CHANCES. THE 00Z ECMWF IS COMPLETELY DRY THIS MORNING AND TOTALLY MISSES THE ONGOING CONVECTION. THE 00Z GFS IS NOT MUCH BETTER AND ALSO LARGELY MISSES THIS MORNINGS CONVECTION. WILL GENERALLY LEAN MORE TOWARDS THE RAPID UPDATE HIGHER RESOLUTION MODELS IN THIS PATTERN...WHICH WOULD INCLUDE THE 06Z NAM...HRRR...AND WRF MEMBERS. THESE MODELS ARE ALL PICKING UP ON OUR EARLY MORNING CONVECTION. THE HRRR AND 06Z NAM INDICATE THAT THERE IS REALLY NO CLEAR CUT DRY PERIOD NEAR THE TROUGH AXIS TODAY AND THUNDERSTORMS MAY POTENTIALLY CONTINUE TO DEVELOP AND DECAY ALONG THIS TROUGH THROUGHOUT THE DAY AND INTO THE EVENING UNTIL THE TROUGH FINALLY SLIPS SOUTHEAST OF OUR FORECAST AREA. THIS SEEMS LIKE MORE OF AN ISOLATED CONVECTIVE SET UP...BUT AREAS THAT DO CATCH A STORM OR TWO COULD PICK UP A QUICK INCH OR MORE GIVEN PRECIPITABLE WATER VALUES OF AROUND 1.5 INCHES. THE HRRR WITH ITS RAPID UPDATES MAY END UP BEING THE MODEL OF CHOICE TODAY. EXPECT GENERALLY QUIET WEATHER ACROSS THE AREA AFTER MIDNIGHT AS THE TROUGH SHOULD BE SOUTH OF OUR AREA BY THEN. THERE IS A THREAT OF SEVERE WEATHER TODAY...ESPECIALLY THIS AFTERNOON AND EVENING ACROSS THE SOUTHEASTERN HALF OF OUR FORECAST AREA ALONG THE SOUTHWARD SINKING SFC TROUGH. DEEP LAYER SHEAR VALUES WILL GENERALLY BE BETWEEN 30 TO 40 KTS WHILE INSTABILITY WILL BE HIGH. HOWEVER...LOW LEVEL SHEAR IS WEAK...WHICH WILL MAKE TORNADOES UNLIKELY. THEREFORE...ONE SHOULD PRIMARILY BE ON THE LOOK OUT FOR LARGE HAIL AND DAMAGING WINDS WITH THE STRONGEST STORMS. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 349 AM CDT MON JUL 22 2013 MAIN FORECAST CONCERNS WILL BE CHANCES FOR THUNDERSTORMS ON AND OFF THROUGH THE PERIOD AND TEMPERATURES. MODELS CONTINUE TO HAVE NORTHWEST FLOW ACROSS THE AREA THROUGH THE PERIOD WITH A SERIES OF MAINLY WEAK UPPER LEVEL WAVES. THE MAIN DIFFERENCE BETWEEN THE MODELS IS THAT TIMING AND STRENGTH ARE A LITTLE DIFFERENT WITH EACH MODEL. THE FIRST OF THE UPPER WAVES AFFECTS THE AREA TUESDAY AND TUESDAY NIGHT. THE WAVE MOVES INTO THE AREA DURING THE DAY AND STRENGTHENS SOME DURING THE EVENING. HAVE KEPT A SMALL CHANCE FOR THUNDERSTORMS DURING THE AFTERNOON BUT THE BETTER CHANCE WILL BE DURING THE EVENING AND INTO THE OVERNIGHT FOR MAINLY THE SOUTHEAST PART OF THE AREA. TEMPERATURES WILL BE COOLER THAN TODAY. A SURFACE HIGH ATTEMPTS TO BUILD INTO THE AREA FOR WEDNESDAY AND INTO WEDNESDAY NIGHT. THIS WILL KEEP DRY CONDITIONS DURING THE DAY. TEMPERATURES WILL BE A BIT COOLER. THE DRY CONDITIONS WILL GIVE WAY WEDNESDAY NIGHT TO A CHANCE FOR THUNDERSTORMS IN THE WESTERN PART OF THE AREA AS ANOTHER UPPER LEVEL WAVE MOVES INTO THE AREA. THIS WAVE IS A LITTLE STRONGER AND CHANCES INCREASE FOR THURSDAY AND THURSDAY NIGHT. THE UPPER WAVE MOVES OUT OF THE AREA ON FRIDAY WITH SOME LINGERING THUNDERSTORMS. FRIDAY NIGHT THROUGH SUNDAY THE MODELS HAVE VARIOUS WEAK UPPER LEVEL WAVES THAT AFFECT PARTS OF THE FORECAST AREA. DO NOT EXPECT VERY MUCH PRECIPITATION BUT THERE COULD BE AN ISOLATED THUNDERSTORM HERE OR THERE DURING THE PERIOD. TEMPERATURES WILL REMAIN ON THE COOLER SIDE DURING THIS TIME. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1239 PM CDT MON JUL 22 2013 AS A RESULT OF THIS PESKY NORTHWESTERLY FLOW ALOFT...THE CHALLENGE HERE DURING THIS TAF PERIOD IS DETERMINING PRECIPITATION CHANCES OVER THE TERMINAL. THUNDERSTORMS CANNOT BE COMPLETELY RULED OUT TODAY/TONIGHT...HOWEVER...CONFIDENCE IS NOT HIGH ENOUGH AT THE MOMENT TO PUT A MENTION IN THE TAF. WILL AMEND IF CONDITIONS CHANGE. WITH THAT BEING SAID...VFR CONDITIONS SHOULD PREVAIL AT THE TERMINAL SITE. THE WIND WILL REMAIN FROM THE NORTH FOR THE FIRST SEVERAL HOURS AS A COLD FRONT SLIDES THROUGH THE REGION...BUT THE WIND SHOULD SHIFT AND BECOME MORE WESTERLY AS WE PROGRESS THROUGH OVERNIGHT PERIOD. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ UPDATE...PFANNKUCH SHORT TERM...WESELY LONG TERM...JCB AVIATION...GUERRERO
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1112 AM CDT MON JUL 22 2013 .UPDATE... UPDATED FOR CONVECTIVE TRENDS THROUGH THE DAY && .DISCUSSION... 12Z UPPER AIR ANALYSIS INDICATED A POTENT UPPER LEVEL SYSTEM MOVING THROUGH SRN CANADA ASSOCIATED WITH AN 80 KT H3 JET AND 50 M H5 HEIGHT FALLS. THIS WAS ALLOWING FOR A COLD FRONT TO PUSH SEWD INTO THE FA THIS MORNING...AND EXTENDED FROM NEAR SUX TO ODX AT 15Z. THERE WAS ALSO A 60 KT JET SEGMENT ASSOCIATED WITH A SUBTLE SHRTWV TROUGH OVER ERN WY. MID-LEVEL LAPSE RATES HAD IMPROVED OVER THE LAST 24 HOURS ACROSS THE CENTRAL PLAINS WITH H7 TO H5 DELTA-T VALUES OF +20 C FROM OAX UPSTREAM TO RAP/LBF AND INTO THE ROCKIES. A NWRLY H85 WND AHEAD OF THE COLD FRONT HAD PUSHED THE MOISTURE AXIS TO THE S AND E OF OAX...BUT +15 C H85 DEW POINTS WERE NOTED ALONG AND JUST BEHIND THE FRONT /INCLUDING A 16 C H85 DEW POINT AT RAP/. THE COMBINATION OF THE BETTER MID LEVEL LAPSE RATES AND MOISTURE ALONG THE FRONT WILL LEAD TO A STRONGLY UNSTABLE ATMOSPHERE ACROSS THE FA THIS AFTERNOON WITH MLCAPE APPROACHING 3500 J/KG...WHICH APPEARS REASONABLE GIVEN THE MODIFIED KOAX 12Z SOUNDING. KOAX 88-D CONTS TO INDC SOME SCT TSRA JUST BEHIND THE SFC BOUNDARY MOVING INTO NE NEB LATE THIS MORNING AND WE FEEL THIS ACTIVITY WILL CONT TO DRIFT TO THE SE THRU THE AFTN. THIS ACTIVITY IS CURRENT ELEVATED ABOVE THE NOCTURNAL INVERSION WITH A LIKELY EFFECTIVE INFLOW LAYER JUST ABOVE 850 MB. THIS ACTIVITY WAS HANDLED WELL BY GOING FORECAST REQUIRING LITTLE CHANGE. THE MAIN NEGATIVE THAT WILL LIKELY KEEP CONVECTIVE COVERAGE FAIRLY ISOLATED TODAY IS THE LACK OF MORE ORGANIZED LARGE-SCALE ASCENT AND RATHER WEAK SFC CONVERGENCE ALONG THE FRONT. THE WY SHRTWV TROUGH WILL LIKELY AFFECT WRN NEB INTO KS AND THE CANADIAN SHRTWV SHOULD STAY WELL TO THE NORTH. THUS THE BEST COVERAGE IS LIKELY TO BE IN WRN IA AND WE WILL CENTER THE HIGHEST POPS THERE WITH MORE ISOLATED ACTIVITY IN E-CNTRL AND SE NEB. THERE IS SOME THREAT OF AN ISO SVR STORM TODAY...BUT WEAK EFFECTIVE SHEAR /GENERALLY LESS THAN 20 KT/ SHOULD KEEP ANY THREAT ISOLATED AND SHORT-LIVED. THE BETTER DEEP LAYER SHEAR /> 30 KT/ WILL ACTUALLY BE OVER THE SRN CWA IF CONVECTION CAN MAKE IT INTO THAT AREA LATE THIS AFTN AND EVENING. ALL THE ACTIVITY WILL LIKELY PUSH OUT OF THE AREA BY MID EVENING...BUT ANOTHER SHRTWV TROUGH /SEEN IN THE 12Z UPPER AIR ANALYSIS OVER WA/ MAY LEAD TO CONVECTION ROLLING OFF THE HIGH PLAINS OVERNIGHT AND THIS WILL BE DISCUSSED MORE IN THE AFTERNOON AFD. BOUSTEAD && .AVIATION... 18Z TAFS FOR KOMA...KOFK...KLNK VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD EXCEPT IN POSSIBLE TSRA. THIS APPEARS MOST LIKELY AT OMA FROM AROUND 19-22Z AND LNK AROUND 21-24Z WITH MVFR CIGS/VISBY POSSIBLE. OTHERWISE A SFC CDFNT WILL MOV THROUGH OFK NEAR 18Z AND OMA/LNK BY AROUND 21Z WITH WINDS SHIFTING FROM SW TO NW AT ALL LOCATIONS. MOST CLEAR CONDITIONS ARE EXPECTED OVERNIGHT WITH LIGHT WINDS. && PREV DISCUSSION... /ISSUED 304 AM CDT MON JUL 22 2013/ DISCUSSION... PRIMARY CONCERN TODAY WILL BE TIMING AND AREAL EXTENT OF POSSIBLE CONVECTION AS A COLD FRONT MOVES INTO THE AREA. THE FRONT AT 07Z WAS LOCATED FROM NORTHEAST WYOMING THROUGH CENTRAL SOUTH DAKOTA INTO NORTHWEST WYOMING. CONVECTION ACROSS WESTERN NEBRASKA WILL NOT MAKE IT THIS FAR EAST. THE FRONT MOVES INTO NORTHEAST NEBRASKA BY 15Z...THEN CONTINUES TO MOVE SOUTH THROUGH THE FORECAST AREA THROUGH 03Z. BELIEVE THAT IT MAY TAKE UNTIL 17-18Z BEFORE ANY STORMS MIGHT FIRE...BASED ON RECENT RAP MODEL RUNS...PERHAPS IN THE ALBION TO WAYNE VICINITY...THEN APPROACHING THE LINCOLN AND OMAHA AREAS 21-00Z...THEN PUSHING SOUTH OF I80 THROUGH EARLY EVENING BEFORE EXITING ALTOGETHER. SPC HAS SLIGHT RISK OF SEVERE WEATHER IN PLACE ALONG AND SOUTH OF I80...GIVEN TEMPS WARMING INTO THE LOWER 90S...AND SURFACE DEWPOINTS IN THE LOWER 70S...WHICH SHOULD YIELD MUCAPES 2000-3000 J/KG. 0-6KM BULK SHEAR OF 30 TO 35 KNOTS ALONG WITH HIGH INSTABILITY COULD RESULT IN A HAIL/WIND THREAT WITH STORMS THAT DEVELOP DURING PEAK HEATING. SECONDARY CONCERN IS POTENTIAL CONVECTION ON TUESDAY. REGION REMAINS IN NORTHWEST FLOW...AND THE NAM/SREF/ECMWF ALL SUGGEST THAT ANOTHER WAVE WILL MOVE INTO THE AREA FROM THE NORTHERN HIGH PLAINS OUT OF SOUTH DAKOTA. THIS WILL BE IN COMPETITION WITH THE SURFACE HIGH RIDGE NOSING SOUTHWARD INTO THE MID MISSOURI VALLEY WITH A DRIER NORTHEAST TO EAST WIND. THE GFS MEANWHILE KEEPS THINGS A LITTLE FURTHER WEST...WITH ANY CONVECTION CLIPPING JUST THE SOUTHERN FORECAST AREA DURING THE AFTERNOON. FEEL THERE`S ENOUGH SUPPORT TO MENTION AT LEAST A SLIGHT CHANCE...AND IF MODEL SOLUTIONS REMAIN CONSISTENT FOR ANOTHER RUN...WOULD CONSIDER INCREASING THE POPS FOR TUESDAY. WHATEVER DOES DEVELOP WOULD LINGER TUESDAY EVENING IN THE SOUTHERN FORECAST AREA...THEN PUSH SOUTH BY DAYBREAK WEDNESDAY. COOLER AND SLIGHTLY BELOW NORMAL TEMPS ARE EXPECTED TUESDAY AS WELL. THE NEXT WAVE CROSSES THE ROCKIES AND BEGINS TO AFFECT OUR AREA BY THURSDAY AFTERNOON AND LINGERS THROUGH FRIDAY. ANOTHER WAVE MOVING THROUGH THE GREAT LAKES COULD ALSO PUT PART OF OUR AREA ON THE WESTERN PERIPHERY OF PRECIP SATURDAY. AND YET ANOTHER WAVE COULD BRING A SMALL PRECIP CHANCE SUNDAY INTO MONDAY. DEWALD && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$
AREA FORECAST DISCUSSION
NWS HASTINGS NE
911 AM CDT MON JUL 22 2013 .UPDATE... ISSUED AT 911 AM CDT MON JUL 22 2013 FIRST FORECAST UPDATE OF THE DAY HAS BEEN SENT. IN SHORT...ANOTHER TRICKY DAY/EVENING OF THUNDERSTORM CHANCES AWAITS THE LOCAL AREA. ESSENTIALLY...THE ONLY NOTABLE CHANGE FROM PREVIOUS FORECAST SO FAR WAS TO TRIM CENTRAL/NORTHEAST PORTIONS OF THE CWA FROM ANY THUNDERSTORM MENTION THIS MORNING...WHILE LEAVING MORNING CHANCES INTACT IN KS ZONES...AND MAINLY WEST OF A GOTHENBURG-ALMA LINE IN NEBRASKA TO ACCOUNT FOR THE FAIRLY PERSISTENT NARROW NORTHWEST- SOUTHEAST AXIS OF CONVECTION PRIMARILY AFFECTING FURNAS COUNTY AT THIS TIME. OTHER THAN MAYBE SOME SMALL HAIL...NOT EXPECTING A MORNING SEVERE THREAT. FOR THIS AFTERNOON...ITS HARD TO ARGUE WITH THE SPC SLIGHT RISK FOR ROUGHLY THE SOUTHEAST 2/3 OF THE CWA...ALTHOUGH ITS TOUGH TO SAY WHETHER WE MIGHT ONLY GET 1 OR 2 ISOLATED STRONG-SEVERE STORMS...OR POTENTIALLY MORE SCATTERED COVERAGE. EITHER WAY...THE PRIMARY FORCING MECHANISM ALOFT LOOKS TO BE A FAIRLY SUBTLE SHORTWAVE TROUGH DRIFTING EAST-SOUTHEAST OUT OF WYOMING...WHILE AT THE SURFACE A FAIRLY WEAK COLD FRONT WILL SINK SOUTHWARD INTO PARTS OF THE CWA AS THE DAY WEARS ON...PROVIDING AT LEAST LIMITED LOW-LEVEL CONVERGENCE. THE LATEST RAP FORECAST VALID FOR 21Z/4PM PAINTS 1000-2500 J/KG OF 0-1KM MLCAPE ACROSS MOST OF THE CWA...HIGHEST IN THE SOUTH...IN THE PRESENCE OF DECENT 0-6KM DEEP LAYER SHEAR OF 35-40KT...SO CERTAINLY A THREAT FOR SOME SOUTHEAST-MOVING STRONG TO SEVERE STORMS AND POTENTIALLY SUPERCELLS EXISTS...ALTHOUGH WORKING AGAINST STORM FORMATION APPEARS TO BE AT LEAST A WEAK CAP EVIDENT ON FORECAST SOUNDINGS AROUND 700-650 MILLIBARS...SO ITS ALSO NOT OUT OF THE QUESTION THAT OUR LOCAL AREA COULD LARGELY STEER CLEAR OF AN AFTERNOON/EVENING STORM THREAT...WITH BETTER CHANCES POTENTIALLY FOCUSING JUST TO OUR SOUTH/EAST. EVEN THOUGH THE GREATEST SEVERE THREAT WOULD THEORETICALLY FOCUS ACROSS SOUTHERN PORTIONS OF OUR AREA...HAVE PUT AT LEAST A SLIGHT CHANCE OF STORMS EVEN IN FAR NORTHERN COUNTIES FOR AT LEAST A FEW HOURS THIS AFTERNOON. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 349 AM CDT MON JUL 22 2013 THE CHALLENGING UPPER LEVEL NORTHWEST FLOW PATTERN WILL PERSIST THROUGH THE PERIOD. A SFC AREA OF LOW PRESSURE OVER EASTERN COLORADO/WESTERN KANSAS WILL SAG SOUTH TODAY DRAGGING A SFC TROUGH SOUTH THROUGH OUR FORECAST AREA. THE WIND AHEAD OF THE TROUGH WILL GENERALLY BE OUT OF THE SOUTH TO SOUTHEAST...WHILE AN EAST TO NORTHEAST WIND CAN BE EXPECTED BEHIND THE TROUGH AXIS. THIS WIND SHIFT BOUNDARY SHOULD BE LOCATED NEAR THE NEBRASKA/KANSAS BOARDER BY MID AFTERNOON. HIGH TEMPERATURES WILL BE THE HOTTEST SOUTH OF THE FRONT ACROSS NORTHERN KANSAS WHERE HIGHS SHOULD BE IN THE UPPER 90S AND MAY APPROACH 100. GENERALLY LOW TO MID 90S ARE EXPECTED FURTHER NORTH ACROSS NEBRASKA. THE WIND ON BOTH SIDES OF THE TROUGH WILL BE RATHER LIGHT AND EVEN LIGHT AND VARIABLE NEAR THE BOUNDARY MAKING FOR AN UNCOMFORTABLE HEAT WITHOUT MUCH AIR FLOW. THUNDERSTORMS ARE ONGOING EARLY THIS MORNING ACROSS PORTIONS OF DAWSON AND GOSPER COUNTIES. EXPECT THIS CLUSTER OF THUNDERSTORMS WILL CONTINUE TO TRACK TO THE SOUTHEAST UNTIL AT LEAST DAWN AND MAY POTENTIALLY SURVIVE THROUGH MID MORNING IMPACTING OUR FAR SOUTHWESTERN COUNTIES INCLUDING PORTIONS OF NORTH CENTRAL KANSAS TO THE WEST OF HIGHWAY 281. FORECAST MODELS CONTINUE TO STRUGGLE WITH PRECIPITATION CHANCES TODAY INTO TONIGHT LEADING TO CONTINUED LOW CONFIDENCE IN PRECIPITATION CHANCES. THE 00Z ECMWF IS COMPLETELY DRY THIS MORNING AND TOTALLY MISSES THE ONGOING CONVECTION. THE 00Z GFS IS NOT MUCH BETTER AND ALSO LARGELY MISSES THIS MORNINGS CONVECTION. WILL GENERALLY LEAN MORE TOWARDS THE RAPID UPDATE HIGHER RESOLUTION MODELS IN THIS PATTERN...WHICH WOULD INCLUDE THE 06Z NAM...HRRR...AND WRF MEMBERS. THESE MODELS ARE ALL PICKING UP ON OUR EARLY MORNING CONVECTION. THE HRRR AND 06Z NAM INDICATE THAT THERE IS REALLY NO CLEAR CUT DRY PERIOD NEAR THE TROUGH AXIS TODAY AND THUNDERSTORMS MAY POTENTIALLY CONTINUE TO DEVELOP AND DECAY ALONG THIS TROUGH THROUGHOUT THE DAY AND INTO THE EVENING UNTIL THE TROUGH FINALLY SLIPS SOUTHEAST OF OUR FORECAST AREA. THIS SEEMS LIKE MORE OF AN ISOLATED CONVECTIVE SET UP...BUT AREAS THAT DO CATCH A STORM OR TWO COULD PICK UP A QUICK INCH OR MORE GIVEN PRECIPITABLE WATER VALUES OF AROUND 1.5 INCHES. THE HRRR WITH ITS RAPID UPDATES MAY END UP BEING THE MODEL OF CHOICE TODAY. EXPECT GENERALLY QUIET WEATHER ACROSS THE AREA AFTER MIDNIGHT AS THE TROUGH SHOULD BE SOUTH OF OUR AREA BY THEN. THERE IS A THREAT OF SEVERE WEATHER TODAY...ESPECIALLY THIS AFTERNOON AND EVENING ACROSS THE SOUTHEASTERN HALF OF OUR FORECAST AREA ALONG THE SOUTHWARD SINKING SFC TROUGH. DEEP LAYER SHEAR VALUES WILL GENERALLY BE BETWEEN 30 TO 40 KTS WHILE INSTABILITY WILL BE HIGH. HOWEVER...LOW LEVEL SHEAR IS WEAK...WHICH WILL MAKE TORNADOES UNLIKELY. THEREFORE...ONE SHOULD PRIMARILY BE ON THE LOOK OUT FOR LARGE HAIL AND DAMAGING WINDS WITH THE STRONGEST STORMS. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 349 AM CDT MON JUL 22 2013 MAIN FORECAST CONCERNS WILL BE CHANCES FOR THUNDERSTORMS ON AND OFF THROUGH THE PERIOD AND TEMPERATURES. MODELS CONTINUE TO HAVE NORTHWEST FLOW ACROSS THE AREA THROUGH THE PERIOD WITH A SERIES OF MAINLY WEAK UPPER LEVEL WAVES. THE MAIN DIFFERENCE BETWEEN THE MODELS IS THAT TIMING AND STRENGTH ARE A LITTLE DIFFERENT WITH EACH MODEL. THE FIRST OF THE UPPER WAVES AFFECTS THE AREA TUESDAY AND TUESDAY NIGHT. THE WAVE MOVES INTO THE AREA DURING THE DAY AND STRENGTHENS SOME DURING THE EVENING. HAVE KEPT A SMALL CHANCE FOR THUNDERSTORMS DURING THE AFTERNOON BUT THE BETTER CHANCE WILL BE DURING THE EVENING AND INTO THE OVERNIGHT FOR MAINLY THE SOUTHEAST PART OF THE AREA. TEMPERATURES WILL BE COOLER THAN TODAY. A SURFACE HIGH ATTEMPTS TO BUILD INTO THE AREA FOR WEDNESDAY AND INTO WEDNESDAY NIGHT. THIS WILL KEEP DRY CONDITIONS DURING THE DAY. TEMPERATURES WILL BE A BIT COOLER. THE DRY CONDITIONS WILL GIVE WAY WEDNESDAY NIGHT TO A CHANCE FOR THUNDERSTORMS IN THE WESTERN PART OF THE AREA AS ANOTHER UPPER LEVEL WAVE MOVES INTO THE AREA. THIS WAVE IS A LITTLE STRONGER AND CHANCES INCREASE FOR THURSDAY AND THURSDAY NIGHT. THE UPPER WAVE MOVES OUT OF THE AREA ON FRIDAY WITH SOME LINGERING THUNDERSTORMS. FRIDAY NIGHT THROUGH SUNDAY THE MODELS HAVE VARIOUS WEAK UPPER LEVEL WAVES THAT AFFECT PARTS OF THE FORECAST AREA. DO NOT EXPECT VERY MUCH PRECIPITATION BUT THERE COULD BE AN ISOLATED THUNDERSTORM HERE OR THERE DURING THE PERIOD. TEMPERATURES WILL REMAIN ON THE COOLER SIDE DURING THIS TIME. && .AVIATION...(FOR THE 12Z KGRI TAF THROUGH 12Z TUESDAY MORNING) ISSUED AT 523 AM CDT MON JUL 22 2013 WE CAN NOT COMPLETELY RULE OUT THUNDERSTORMS AT KGRI...BUT ANY THUNDERSTORMS WILL LIKELY BE ISOLATED WITH A VERY LOW PROBABILITY OF IMPACTING THE AIRPORT. CONSEQUENTLY...WILL CONTINUE TO KEEP ALL MENTION OF THUNDERSTORMS OUT OF THE TAF. THE WIND WILL GENERALLY BE LIGHT AND VARIABLE UNTIL AFTERNOON WHEN WE EXPECT THE PREVAILING WIND TO BECOME MORE CONSISTENTLY OUT OF THE EAST NORTHEAST. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ UPDATE...PFANNKUCH SHORT TERM...WESELY LONG TERM...JCB AVIATION...WESELY
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
625 AM CDT MON JUL 22 2013 .AVIATION... 12Z TAFS FOR KOFK...KLNK AND KOMA. AS HAS BEEN THE CASE FOR THE PAST FEW DAYS...THE MAIN CONCERN AND THE PRIMARY CHALLENGE FOR THE TAFS WILL BE THUNDERSTORM DEVELOPMENT. TODAY A COLD FRONT WILL MOVE THROUGH EASTERN NEBRASKA...SWITCHING THE WINDS FROM MOSTLY SOUTHERLY TO THE NORTHWEST. THE FRONT IS EXPECTED TO REACH KOFK AT 16Z...KOMA AT 21Z...AND KLNK AT 22Z. THE FRONT WILL HELP TO TRIGGER THUNDERSTORM DEVELOPMENT...BUT BETTER CHANCES ARE AT KOMA AND KLNK BECAUSE THE INSTABILITY WILL BE GREATER WHEN THE FRONT COMES THROUGH THOSE LOCATIONS. THEREFORE HAVE INCLUDED TSRA PROB30 GROUPS FOR THOSE TWO TAFS. A FEW STRONG OR EVEN SEVERE STORMS WILL BE POSSIBLE. GENERALLY EXPECT ANY CONVECTION THAT DEVELOPS TODAY TO EVENTUALLY DIMINISH OVERNIGHT AND EXPECT VFR CONDITIONS AFTER ANY THUNDERSTORMS. NIETFELD && .PREV DISCUSSION... /ISSUED 304 AM CDT MON JUL 22 2013/ .DISCUSSION... PRIMARY CONCERN TODAY WILL BE TIMING AND AREAL EXTENT OF POSSIBLE CONVECTION AS A COLD FRONT MOVES INTO THE AREA. THE FRONT AT 07Z WAS LOCATED FROM NORTHEAST WYOMING THROUGH CENTRAL SOUTH DAKOTA INTO NORTHWEST WYOMING. CONVECTION ACROSS WESTERN NEBRASKA WILL NOT MAKE IT THIS FAR EAST. THE FRONT MOVES INTO NORTHEAST NEBRASKA BY 15Z...THEN CONTINUES TO MOVE SOUTH THROUGH THE FORECAST AREA THROUGH 03Z. BELIEVE THAT IT MAY TAKE UNTIL 17-18Z BEFORE ANY STORMS MIGHT FIRE...BASED ON RECENT RAP MODEL RUNS...PERHAPS IN THE ALBION TO WAYNE VICINITY...THEN APPROACHING THE LINCOLN AND OMAHA AREAS 21-00Z...THEN PUSHING SOUTH OF I80 THROUGH EARLY EVENING BEFORE EXITING ALTOGETHER. SPC HAS SLIGHT RISK OF SEVERE WEATHER IN PLACE ALONG AND SOUTH OF I80...GIVEN TEMPS WARMING INTO THE LOWER 90S...AND SURFACE DEWPOINTS IN THE LOWER 70S...WHICH SHOULD YIELD MUCAPES 2000-3000 J/KG. 0-6KM BULK SHEAR OF 30 TO 35 KNOTS ALONG WITH HIGH INSTABILITY COULD RESULT IN A HAIL/WIND THREAT WITH STORMS THAT DEVELOP DURING PEAK HEATING. SECONDARY CONCERN IS POTENTIAL CONVECTION ON TUESDAY. REGION REMAINS IN NORTHWEST FLOW...AND THE NAM/SREF/ECMWF ALL SUGGEST THAT ANOTHER WAVE WILL MOVE INTO THE AREA FROM THE NORTHERN HIGH PLAINS OUT OF SOUTH DAKOTA. THIS WILL BE IN COMPETITION WITH THE SURFACE HIGH RIDGE NOSING SOUTHWARD INTO THE MID MISSOURI VALLEY WITH A DRIER NORTHEAST TO EAST WIND. THE GFS MEANWHILE KEEPS THINGS A LITTLE FURTHER WEST...WITH ANY CONVECTION CLIPPING JUST THE SOUTHERN FORECAST AREA DURING THE AFTERNOON. FEEL THERE`S ENOUGH SUPPORT TO MENTION AT LEAST A SLIGHT CHANCE...AND IF MODEL SOLUTIONS REMAIN CONSISTENT FOR ANOTHER RUN...WOULD CONSIDER INCREASING THE POPS FOR TUESDAY. WHATEVER DOES DEVELOP WOULD LINGER TUESDAY EVENING IN THE SOUTHERN FORECAST AREA...THEN PUSH SOUTH BY DAYBREAK WEDNESDAY. COOLER AND SLIGHTLY BELOW NORMAL TEMPS ARE EXPECTED TUESDAY AS WELL. THE NEXT WAVE CROSSES THE ROCKIES AND BEGINS TO AFFECT OUR AREA BY THURSDAY AFTERNOON AND LINGERS THROUGH FRIDAY. ANOTHER WAVE MOVING THROUGH THE GREAT LAKES COULD ALSO PUT PART OF OUR AREA ON THE WESTERN PERIPHERY OF PRECIP SATURDAY. AND YET ANOTHER WAVE COULD BRING A SMALL PRECIP CHANCE SUNDAY INTO MONDAY. DEWALD && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$
AREA FORECAST DISCUSSION
NWS HASTINGS NE
532 AM CDT MON JUL 22 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 349 AM CDT MON JUL 22 2013 THE CHALLENGING UPPER LEVEL NORTHWEST FLOW PATTERN WILL PERSIST THROUGH THE PERIOD. A SFC AREA OF LOW PRESSURE OVER EASTERN COLORADO/WESTERN KANSAS WILL SAG SOUTH TODAY DRAGGING A SFC TROUGH SOUTH THROUGH OUR FORECAST AREA. THE WIND AHEAD OF THE TROUGH WILL GENERALLY BE OUT OF THE SOUTH TO SOUTHEAST...WHILE AN EAST TO NORTHEAST WIND CAN BE EXPECTED BEHIND THE TROUGH AXIS. THIS WIND SHIFT BOUNDARY SHOULD BE LOCATED NEAR THE NEBRASKA/KANSAS BOARDER BY MID AFTERNOON. HIGH TEMPERATURES WILL BE THE HOTTEST SOUTH OF THE FRONT ACROSS NORTHERN KANSAS WHERE HIGHS SHOULD BE IN THE UPPER 90S AND MAY APPROACH 100. GENERALLY LOW TO MID 90S ARE EXPECTED FURTHER NORTH ACROSS NEBRASKA. THE WIND ON BOTH SIDES OF THE TROUGH WILL BE RATHER LIGHT AND EVEN LIGHT AND VARIABLE NEAR THE BOUNDARY MAKING FOR AN UNCOMFORTABLE HEAT WITHOUT MUCH AIR FLOW. THUNDERSTORMS ARE ONGOING EARLY THIS MORNING ACROSS PORTIONS OF DAWSON AND GOSPER COUNTIES. EXPECT THIS CLUSTER OF THUNDERSTORMS WILL CONTINUE TO TRACK TO THE SOUTHEAST UNTIL AT LEAST DAWN AND MAY POTENTIALLY SURVIVE THROUGH MID MORNING IMPACTING OUR FAR SOUTHWESTERN COUNTIES INCLUDING PORTIONS OF NORTH CENTRAL KANSAS TO THE WEST OF HIGHWAY 281. FORECAST MODELS CONTINUE TO STRUGGLE WITH PRECIPITATION CHANCES TODAY INTO TONIGHT LEADING TO CONTINUED LOW CONFIDENCE IN PRECIPITATION CHANCES. THE 00Z ECMWF IS COMPLETELY DRY THIS MORNING AND TOTALLY MISSES THE ONGOING CONVECTION. THE 00Z GFS IS NOT MUCH BETTER AND ALSO LARGELY MISSES THIS MORNINGS CONVECTION. WILL GENERALLY LEAN MORE TOWARDS THE RAPID UPDATE HIGHER RESOLUTION MODELS IN THIS PATTERN...WHICH WOULD INCLUDE THE 06Z NAM...HRRR...AND WRF MEMBERS. THESE MODELS ARE ALL PICKING UP ON OUR EARLY MORNING CONVECTION. THE HRRR AND 06Z NAM INDICATE THAT THERE IS REALLY NO CLEAR CUT DRY PERIOD NEAR THE TROUGH AXIS TODAY AND THUNDERSTORMS MAY POTENTIALLY CONTINUE TO DEVELOP AND DECAY ALONG THIS TROUGH THROUGHOUT THE DAY AND INTO THE EVENING UNTIL THE TROUGH FINALLY SLIPS SOUTHEAST OF OUR FORECAST AREA. THIS SEEMS LIKE MORE OF AN ISOLATED CONVECTIVE SET UP...BUT AREAS THAT DO CATCH A STORM OR TWO COULD PICK UP A QUICK INCH OR MORE GIVEN PRECIPITABLE WATER VALUES OF AROUND 1.5 INCHES. THE HRRR WITH ITS RAPID UPDATES MAY END UP BEING THE MODEL OF CHOICE TODAY. EXPECT GENERALLY QUIET WEATHER ACROSS THE AREA AFTER MIDNIGHT AS THE TROUGH SHOULD BE SOUTH OF OUR AREA BY THEN. THERE IS A THREAT OF SEVERE WEATHER TODAY...ESPECIALLY THIS AFTERNOON AND EVENING ACROSS THE SOUTHEASTERN HALF OF OUR FORECAST AREA ALONG THE SOUTHWARD SINKING SFC TROUGH. DEEP LAYER SHEAR VALUES WILL GENERALLY BE BETWEEN 30 TO 40 KTS WHILE INSTABILITY WILL BE HIGH. HOWEVER...LOW LEVEL SHEAR IS WEAK...WHICH WILL MAKE TORNADOES UNLIKELY. THEREFORE...ONE SHOULD PRIMARILY BE ON THE LOOK OUT FOR LARGE HAIL AND DAMAGING WINDS WITH THE STRONGEST STORMS. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 349 AM CDT MON JUL 22 2013 MAIN FORECAST CONCERNS WILL BE CHANCES FOR THUNDERSTORMS ON AND OFF THROUGH THE PERIOD AND TEMPERATURES. MODELS CONTINUE TO HAVE NORTHWEST FLOW ACROSS THE AREA THROUGH THE PERIOD WITH A SERIES OF MAINLY WEAK UPPER LEVEL WAVES. THE MAIN DIFFERENCE BETWEEN THE MODELS IS THAT TIMING AND STRENGTH ARE A LITTLE DIFFERENT WITH EACH MODEL. THE FIRST OF THE UPPER WAVES AFFECTS THE AREA TUESDAY AND TUESDAY NIGHT. THE WAVE MOVES INTO THE AREA DURING THE DAY AND STRENGTHENS SOME DURING THE EVENING. HAVE KEPT A SMALL CHANCE FOR THUNDERSTORMS DURING THE AFTERNOON BUT THE BETTER CHANCE WILL BE DURING THE EVENING AND INTO THE OVERNIGHT FOR MAINLY THE SOUTHEAST PART OF THE AREA. TEMPERATURES WILL BE COOLER THAN TODAY. A SURFACE HIGH ATTEMPTS TO BUILD INTO THE AREA FOR WEDNESDAY AND INTO WEDNESDAY NIGHT. THIS WILL KEEP DRY CONDITIONS DURING THE DAY. TEMPERATURES WILL BE A BIT COOLER. THE DRY CONDITIONS WILL GIVE WAY WEDNESDAY NIGHT TO A CHANCE FOR THUNDERSTORMS IN THE WESTERN PART OF THE AREA AS ANOTHER UPPER LEVEL WAVE MOVES INTO THE AREA. THIS WAVE IS A LITTLE STRONGER AND CHANCES INCREASE FOR THURSDAY AND THURSDAY NIGHT. THE UPPER WAVE MOVES OUT OF THE AREA ON FRIDAY WITH SOME LINGERING THUNDERSTORMS. FRIDAY NIGHT THROUGH SUNDAY THE MODELS HAVE VARIOUS WEAK UPPER LEVEL WAVES THAT AFFECT PARTS OF THE FORECAST AREA. DO NOT EXPECT VERY MUCH PRECIPITATION BUT THERE COULD BE AN ISOLATED THUNDERSTORM HERE OR THERE DURING THE PERIOD. TEMPERATURES WILL REMAIN ON THE COOLER SIDE DURING THIS TIME. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 523 AM CDT MON JUL 22 2013 WE CAN NOT COMPLETELY RULE OUT THUNDERSTORMS AT KGRI...BUT ANY THUNDERSTORMS WILL LIKELY BE ISOLATED WITH A VERY LOW PROBABILITY OF IMPACTING THE AIRPORT. CONSEQUENTLY...WILL CONTINUE TO KEEP ALL MENTION OF THUNDERSTORMS OUT OF THE TAF. THE WIND WILL GENERALLY BE LIGHT AND VARIABLE UNTIL AFTERNOON WHEN WE EXPECT THE PREVAILING WIND TO BECOME MORE CONSISTENTLY OUT OF THE EAST NORTHEAST. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM...WESELY LONG TERM...JCB AVIATION...WESELY
AREA FORECAST DISCUSSION
NWS HASTINGS NE
431 AM CDT MON JUL 22 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 349 AM CDT MON JUL 22 2013 THE CHALLENGING UPPER LEVEL NORTHWEST FLOW PATTERN WILL PERSIST THROUGH THE PERIOD. A SFC AREA OF LOW PRESSURE OVER EASTERN COLORADO/WESTERN KANSAS WILL SAG SOUTH TODAY DRAGGING A SFC TROUGH SOUTH THROUGH OUR FORECAST AREA. THE WIND AHEAD OF THE TROUGH WILL GENERALLY BE OUT OF THE SOUTH TO SOUTHEAST...WHILE AN EAST TO NORTHEAST WIND CAN BE EXPECTED BEHIND THE TROUGH AXIS. THIS WIND SHIFT BOUNDARY SHOULD BE LOCATED NEAR THE NEBRASKA/KANSAS BOARDER BY MID AFTERNOON. HIGH TEMPERATURES WILL BE THE HOTTEST SOUTH OF THE FRONT ACROSS NORTHERN KANSAS WHERE HIGHS SHOULD BE IN THE UPPER 90S AND MAY APPROACH 100. GENERALLY LOW TO MID 90S ARE EXPECTED FURTHER NORTH ACROSS NEBRASKA. THE WIND ON BOTH SIDES OF THE TROUGH WILL BE RATHER LIGHT AND EVEN LIGHT AND VARIABLE NEAR THE BOUNDARY MAKING FOR AN UNCOMFORTABLE HEAT WITHOUT MUCH AIR FLOW. THUNDERSTORMS ARE ONGOING EARLY THIS MORNING ACROSS PORTIONS OF DAWSON AND GOSPER COUNTIES. EXPECT THIS CLUSTER OF THUNDERSTORMS WILL CONTINUE TO TRACK TO THE SOUTHEAST UNTIL AT LEAST DAWN AND MAY POTENTIALLY SURVIVE THROUGH MID MORNING IMPACTING OUR FAR SOUTHWESTERN COUNTIES INCLUDING PORTIONS OF NORTH CENTRAL KANSAS TO THE WEST OF HIGHWAY 281. FORECAST MODELS CONTINUE TO STRUGGLE WITH PRECIPITATION CHANCES TODAY INTO TONIGHT LEADING TO CONTINUED LOW CONFIDENCE IN PRECIPITATION CHANCES. THE 00Z ECMWF IS COMPLETELY DRY THIS MORNING AND TOTALLY MISSES THE ONGOING CONVECTION. THE 00Z GFS IS NOT MUCH BETTER AND ALSO LARGELY MISSES THIS MORNINGS CONVECTION. WILL GENERALLY LEAN MORE TOWARDS THE RAPID UPDATE HIGHER RESOLUTION MODELS IN THIS PATTERN...WHICH WOULD INCLUDE THE 06Z NAM...HRRR...AND WRF MEMBERS. THESE MODELS ARE ALL PICKING UP ON OUR EARLY MORNING CONVECTION. THE HRRR AND 06Z NAM INDICATE THAT THERE IS REALLY NO CLEAR CUT DRY PERIOD NEAR THE TROUGH AXIS TODAY AND THUNDERSTORMS MAY POTENTIALLY CONTINUE TO DEVELOP AND DECAY ALONG THIS TROUGH THROUGHOUT THE DAY AND INTO THE EVENING UNTIL THE TROUGH FINALLY SLIPS SOUTHEAST OF OUR FORECAST AREA. THIS SEEMS LIKE MORE OF AN ISOLATED CONVECTIVE SET UP...BUT AREAS THAT DO CATCH A STORM OR TWO COULD PICK UP A QUICK INCH OR MORE GIVEN PRECIPITABLE WATER VALUES OF AROUND 1.5 INCHES. THE HRRR WITH ITS RAPID UPDATES MAY END UP BEING THE MODEL OF CHOICE TODAY. EXPECT GENERALLY QUIET WEATHER ACROSS THE AREA AFTER MIDNIGHT AS THE TROUGH SHOULD BE SOUTH OF OUR AREA BY THEN. THERE IS A THREAT OF SEVERE WEATHER TODAY...ESPECIALLY THIS AFTERNOON AND EVENING ACROSS THE SOUTHEASTERN HALF OF OUR FORECAST AREA ALONG THE SOUTHWARD SINKING SFC TROUGH. DEEP LAYER SHEAR VALUES WILL GENERALLY BE BETWEEN 30 TO 40 KTS WHILE INSTABILITY WILL BE HIGH. HOWEVER...LOW LEVEL SHEAR IS WEAK...WHICH WILL MAKE TORNADOES UNLIKELY. THEREFORE...ONE SHOULD PRIMARILY BE ON THE LOOK OUT FOR LARGE HAIL AND DAMAGING WINDS WITH THE STRONGEST STORMS. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 349 AM CDT MON JUL 22 2013 MAIN FORECAST CONCERNS WILL BE CHANCES FOR THUNDERSTORMS ON AND OFF THROUGH THE PERIOD AND TEMPERATURES. MODELS CONTINUE TO HAVE NORTHWEST FLOW ACROSS THE AREA THROUGH THE PERIOD WITH A SERIES OF MAINLY WEAK UPPER LEVEL WAVES. THE MAIN DIFFERENCE BETWEEN THE MODELS IS THAT TIMING AND STRENGTH ARE A LITTLE DIFFERENT WITH EACH MODEL. THE FIRST OF THE UPPER WAVES AFFECTS THE AREA TUESDAY AND TUESDAY NIGHT. THE WAVE MOVES INTO THE AREA DURING THE DAY AND STRENGTHENS SOME DURING THE EVENING. HAVE KEPT A SMALL CHANCE FOR THUNDERSTORMS DURING THE AFTERNOON BUT THE BETTER CHANCE WILL BE DURING THE EVENING AND INTO THE OVERNIGHT FOR MAINLY THE SOUTHEAST PART OF THE AREA. TEMPERATURES WILL BE COOLER THAN TODAY. A SURFACE HIGH ATTEMPTS TO BUILD INTO THE AREA FOR WEDNESDAY AND INTO WEDNESDAY NIGHT. THIS WILL KEEP DRY CONDITIONS DURING THE DAY. TEMPERATURES WILL BE A BIT COOLER. THE DRY CONDITIONS WILL GIVE WAY WEDNESDAY NIGHT TO A CHANCE FOR THUNDERSTORMS IN THE WESTERN PART OF THE AREA AS ANOTHER UPPER LEVEL WAVE MOVES INTO THE AREA. THIS WAVE IS A LITTLE STRONGER AND CHANCES INCREASE FOR THURSDAY AND THURSDAY NIGHT. THE UPPER WAVE MOVES OUT OF THE AREA ON FRIDAY WITH SOME LINGERING THUNDERSTORMS. FRIDAY NIGHT THROUGH SUNDAY THE MODELS HAVE VARIOUS WEAK UPPER LEVEL WAVES THAT AFFECT PARTS OF THE FORECAST AREA. DO NOT EXPECT VERY MUCH PRECIPITATION BUT THERE COULD BE AN ISOLATED THUNDERSTORM HERE OR THERE DURING THE PERIOD. TEMPERATURES WILL REMAIN ON THE COOLER SIDE DURING THIS TIME. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1246 AM CDT MON JUL 22 2013 WE CAN NOT COMPLETELY RULE OUT THUNDERSTORMS...BUT ANY THUNDERSTORMS WILL LIKELY BE ISOLATED WITH A VERY LOW PROBABILITY OF IMPACTING THE AIRPORT. CONSEQUENTLY...WILL CONTINUE TO KEEP ALL MENTION OF THUNDERSTORMS OUT OF THE TAF. THE WIND WILL GENERALLY BE LIGHT AND VARIABLE UNTIL AFTERNOON WHEN WE EXPECT THE PREVAILING WIND TO BECOME MORE CONSISTENTLY OUT OF THE THE NORTHEAST. AM CALLING FOR VFR CONDITIONS THROUGHOUT THE PERIOD...BUT WILL HAVE TO WATCH OUT FOR SOME POSSIBLE LOW CLOUD DEVELOPMENT TO THE SOUTH OF KGRI THAT HAS A SLIM CHANCE OF IMPACTING KGRI. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM...WESELY LONG TERM...JCB AVIATION...WESELY
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
355 AM CDT MON JUL 22 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 355 AM CDT MON JUL 22 2013 THUNDERSTORMS WILL MOVE EAST SOUTHEAST OUT OF THE FORECAST AREA THIS MORNING WITH CLEARING SKIES TO THE WEST. COOL FRONT OVER CENTRAL SOUTH DAKOTA IS PROGGED TO MOVE SOUTH ACROSS WESTERN NEBRASKA TODAY AND BE THE FOCUS FOR THUNDERSTORM DEVELOPMENT THIS AFTERNOON OVER THE SOUTHEAST PORTION OF THE FORECAST AREA. TEMPERATURES SIMILAR TO YESTERDAYS WITH SOME UPPER 80S NORTH AND LOW 90S SOUTH. FOCUS THEN SHIFTS NORTH THROUGH THE EARLY MORNING HOURS OF TUESDAY WITH BOUNDARY LYING ACROSS WESTERN NEBRASKA AND WEAK WAVE MOVING THROUGH FAST NORTHWEST FLOW EXPECTED TO FIRE OFF SOME THUNDERSTORMS GENERALLY NORTH OF HIGHWAY 2 THROUGH THE EARLY MORNING. LOWS AROUND 60. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 355 AM CDT MON JUL 22 2013 MAIN FORECASTING CONCERN IN THE EXTENDED PERIODS CONTINUES TO BE PRECIPITATION CHANCES...ESPECIALLY SINCE TIMING AND LOCATIONAL DIFFERENCES REMAIN PROBLEMATIC GIVEN THE LOW RUN TO RUN CONSISTENCY IN THE SMALL AMPLITUDE PERTURBATIONS WITHIN NORTHWESTERLY FLOW. THE FIRST OF THESE WEAK PERTURBATIONS IS SHOWN TO CROSS THE NORTHERN/CENTRAL PLAINS TUESDAY INTO EARLY WEDNESDAY...BRINGING A SLIGHT CHANCE OF STORMS BACK TO THE AREA FROM NORTHWEST TO SOUTHEAST. PARAMETERS ARE NOT TOO FAVORABLE FOR SEVERE DEVELOPMENT AS SHEAR IS SUFFICIENT...BUT INSTABILITY IS SOMEWHAT LACKING. THEREAFTER...THE NEXT BEST SHOT AT WIDESPREAD PRECIPITATION COMES EARLY THURSDAY AS THE GFS AND EC LIFT A DECENT SHORTWAVE INTO SOUTHWESTERN/WESTERN NEBRASKA. FRONTAL SUPPORT REMAINS TO THE SOUTH AND WEST OF THE FORECAST AREA...WITH THE BEST INSTABILITY SOUTH AS WELL...HOWEVER BOTH MODELS GENERATE QPF ACROSS MUCH OF THE CWA AS MID TO UPPER TROPOSPHERIC COOLING ASSOCIATED WITH THE WAVE OCCURS. WILL LIMIT POPS IN THE 40 PERCENT RANGE FOR NOW AS STRONGEST FORCING IS REMOVED FROM THE CWA. THE ACTIVE NORTHWEST PATTERN CONTINUES INTO LATE WEEK/WEEKEND WITH ADDITIONAL WAVES BRINGING CONTINUED PRECIPITATION CHANCES TO THE AREA...BUT WITH ALL THE WAFFLING IN THE LONG RANGE PERIODS WILL LIMIT ALL POPS AT 25 PERCENT OR LESS BEYOND FRIDAY MORNING UNTIL TIMING AND LOCATIONAL DIFFERENCES ARE RESOLVED. AS FOR TEMPERATURES...THANKS TO EXPECTED CLOUDS...PRECIPITATION...AND EASTERLY TO SOUTHEASTERLY LOW LEVEL FLOW RECYCLED FROM COOL MIDWEST HIGH...HIGHS SHOULD FALL BACK INTO THE 80S FOR MOST LOCATIONS...ESPECIALLY THURSDAY AND BEYOND. THE WARMEST READINGS WILL ONCE AGAIN BE CONFINED TO OUR FAR WEST...IN CLOSER PROXIMITY TO A SOUTHWESTERN UPPER LEVEL RIDGE ON TUESDAY WITH LOWER 90S POSSIBLE. LOWS WILL REMAIN SEASONAL THROUGH THE EXTENDED PERIODS...WITH MAINLY 60S ANTICIPATED. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1122 PM CDT SUN JUL 21 2013 THE LATEST CONSENSUS OF THE HRRR...NAM AND RAP MODELS SUGGESTS ISOLATED THUNDERSTORMS WOULD CONTINUE THROUGH ABOUT 12Z MONDAY MORNING AND THEN REDEVELOP BETWEEN 21Z-00Z MONDAY AFTERNOON. GIVEN THE STRONG CAP OPERATING MONDAY AFTN...JUST ISOLATED STORMS WOULD BE EXPECTED GENERALLY FROM KBBW WEST THROUGH KLBF...KIML AND KOGA. STORM ACTIVITY...IF IT DEVELOPS...WOULD EXIT THE FCST AREA BY ROUGHLY 03Z. A THIRD SOUTHEASTWARD MOVING AREA OF THUNDERSTORMS COULD THEN BEGIN AFFECTING NRN NEB AROUND 06Z MONDAY EVENING. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...POWER LONG TERM...JACOBS AVIATION...CDC
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
304 AM CDT MON JUL 22 2013 .DISCUSSION... PRIMARY CONCERN TODAY WILL BE TIMING AND AREAL EXTENT OF POSSIBLE CONVECTION AS A COLD FRONT MOVES INTO THE AREA. THE FRONT AT 07Z WAS LOCATED FROM NORTHEAST WYOMING THROUGH CENTRAL SOUTH DAKOTA INTO NORTHWEST WYOMING. CONVECTION ACROSS WESTERN NEBRASKA WILL NOT MAKE IT THIS FAR EAST. THE FRONT MOVES INTO NORTHEAST NEBRASKA BY 15Z...THEN CONTINUES TO MOVE SOUTH THROUGH THE FORECAST AREA THROUGH 03Z. BELIEVE THAT IT MAY TAKE UNTIL 17-18Z BEFORE ANY STORMS MIGHT FIRE...BASED ON RECENT RAP MODEL RUNS...PERHAPS IN THE ALBION TO WAYNE VICINITY...THEN APPROACHING THE LINCOLN AND OMAHA AREAS 21-00Z...THEN PUSHING SOUTH OF I80 THROUGH EARLY EVENING BEFORE EXITING ALTOGETHER. SPC HAS SLIGHT RISK OF SEVERE WEATHER IN PLACE ALONG AND SOUTH OF I80...GIVEN TEMPS WARMING INTO THE LOWER 90S...AND SURFACE DEWPOINTS IN THE LOWER 70S...WHICH SHOULD YIELD MUCAPES 2000-3000 J/KG. 0-6KM BULK SHEAR OF 30 TO 35 KNOTS ALONG WITH HIGH INSTABILITY COULD RESULT IN A HAIL/WIND THREAT WITH STORMS THAT DEVELOP DURING PEAK HEATING. SECONDARY CONCERN IS POTENTIAL CONVECTION ON TUESDAY. REGION REMAINS IN NORTHWEST FLOW...AND THE NAM/SREF/ECMWF ALL SUGGEST THAT ANOTHER WAVE WILL MOVE INTO THE AREA FROM THE NORTHERN HIGH PLAINS OUT OF SOUTH DAKOTA. THIS WILL BE IN COMPETITION WITH THE SURFACE HIGH RIDGE NOSING SOUTHWARD INTO THE MID MISSOURI VALLEY WITH A DRIER NORTHEAST TO EAST WIND. THE GFS MEANWHILE KEEPS THINGS A LITTLE FURTHER WEST...WITH ANY CONVECTION CLIPPING JUST THE SOUTHERN FORECAST AREA DURING THE AFTERNOON. FEEL THERE`S ENOUGH SUPPORT TO MENTION AT LEAST A SLIGHT CHANCE...AND IF MODEL SOLUTIONS REMAIN CONSISTENT FOR ANOTHER RUN...WOULD CONSIDER INCREASING THE POPS FOR TUESDAY. WHATEVER DOES DEVELOP WOULD LINGER TUESDAY EVENING IN THE SOUTHERN FORECAST AREA...THEN PUSH SOUTH BY DAYBREAK WEDNESDAY. COOLER AND SLIGHTLY BELOW NORMAL TEMPS ARE EXPECTED TUESDAY AS WELL. THE NEXT WAVE CROSSES THE ROCKIES AND BEGINS TO AFFECT OUR AREA BY THURSDAY AFTERNOON AND LINGERS THROUGH FRIDAY. ANOTHER WAVE MOVING THROUGH THE GREAT LAKES COULD ALSO PUT PART OF OUR AREA ON THE WESTERN PERIPHERY OF PRECIP SATURDAY. AND YET ANOTHER WAVE COULD BRING A SMALL PRECIP CHANCE SUNDAY INTO MONDAY. DEWALD && .AVIATION...06Z TAFS FOR KOMA...KOFK...KLNK SOME PATCHY FOG POSSIBLE MONDAY MORNING AT KOMA AND KLNK WITH LIGHT WINDS AND HIGH LOW LEVER MOISTURE. A COLD FRONT WILL PUSH ACROSS THE AREA WITH SOUTH/SOUTHWEST WINDS VEERING AROUND TO THE NORTHWEST WITH THE FRONT...AFTER 15Z AT KOFK MONDAY. SHOWERS AND THUNDERSTORMS MAY DEVELOP ALONG THE FRONT WITH GOOD MOISTURE AND INSTABILITY. FOR NOW INCLUDED A COUPLE OF HOURS WITH SHOWERS IN THE AFTERNOON AND EARLY EVENING AT KOMA AND KLNK AND CAN ADD TSRA WHEN THERE IS BETTER CONFIDENCE IN THE COVERAGE AND TIMING. ZAPOTOCNY && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
1126 PM CDT SUN JUL 21 2013 .SYNOPSIS... ISSUED AT 333 PM CDT SUN JUL 21 2013 H5 ANALYSIS FROM THIS MORNING...HAS TWO AREAS OF HIGH PRESSURE ALOFT...THE FIRST OVER NEVADA...AND A SECOND OFF THE CAROLINA COAST. IN BETWEEN...A TROUGH OF LOW PRESSURE EXTENDED ACROSS THE SRN PLAINS FROM KANSAS INTO NERN TX. ACROSS THE NRN TIER OF STATES...INCLUDING THE CENTRAL AND NRN PLAINS...BROAD WEST NORTHWESTERLY AND WESTERLY FLOW EXTENDED FROM THE PACIFIC NW...INTO THE CENTRAL AND NRN PLAINS...EWD INTO THE MID ATLANTIC AND NEW ENGLAND. UPSTREAM OF THE CENTRAL PLAINS...A DECENT SHORTWAVE WAS NOTED OVER SRN ALBERTA...AND A SECOND STRONGER WAVE OVER NWRN PORTIONS OF BRITISH COLUMBIA. AT THE SURFACE...A CONVECTIVE INDUCED MESO HIGH WAS LOCATED OVER SWRN NEBRASKA...WITH DECENT SRLY WINDS NOTED ACROSS THE PANHANDLE ATTM. AS OF 3 PM CDT...TEMPERATURES RANGED FROM 84 AT AINWSWORTH...TO 90 AT IMPERIAL. && .UPDATE... ISSUED AT 921 PM CDT SUN JUL 21 2013 THE HRRR SHOWS THE STORMS ACROSS NW NEB FILLING IN AND BECOMING A LINE OF TSTMS WHICH SWEEP THE FCST AREA OVERNIGHT. THIS IS PROBABLY OVERDONE. THE RAP SHOWS NO STORMS AT ALL BUT INDICATES A 20 TO 30 KT LOW LEVEL JET RUNNING DUE NORTH UP THROUGH WRN NEB TONIGHT. PWAT SHOULD INCREASE TO 1.25 INCHES AND MAYBE MORE ACCORDING TO THE RAP. SO THE FORECAST HAS BEEN UPDATED FOR SCATTERED TSTMS WHICH IS A COMPROMISE OF THE HRRR AND RAP MODELS. NOTE THE 18Z NAM SHOWED ISOLATED STORMS MOVING SOUTHEAST TONIGHT. && .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 333 PM CDT SUN JUL 21 2013 WEAK WAVE IS MOVING ACROSS EAST CENTRAL WYOMING THIS AFTERNOON. THIS WAVE WILL BE THE FOCUS FOR SOME ISOLATED THUNDERSTORMS. LACKING SOME MOISTURE AS DEW PTS IN THE LOWER TO MID 50S. LOW LEVEL JET ALONG THE FRONT RANGE TONIGHT AND WILL AID IN THUNDERSTORM DEVELOPMENT. ATMOSPHERE TOOK A BEATING LAST NIGHT AND EARLY THIS MORNING...SO CONFIDENCE IS LOW ON HOW WIDESPREAD THE COVERAGE WILL BE...HOWEVER SEVERAL REMNANT BOUNDARIES COULD HELP TO SPARK DEVELOPMENT. SINCE THERE IS NOT MUCH OF A CU FIELD...AND ONLY ONE CELL HAS GOTTEN GOING OVER WYOMING...EXPECT COVERAGE TO BE ISOLD. AS FOR TEMPS...THEY SHOULD COOL BACK INTO THE 60S...ALTHOUGH LOCALLY IN THE WEST A BRIEF DIP BELOW 60 IS POSSIBLE. TOMORROW RIDGE REMAINS DOMINATE TO THE SOUTHWEST...WITH MOSTLY SUNNY SKIES THROUGH MOST OF THE DAY. HIGHS INTO THE LOWER/MID 90S ACROSS THE SW TO THE UPPER 80S ACROSS N CENTRAL. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 333 PM CDT SUN JUL 21 2013 MID RANGE...MONDAY NIGHT THROUGH WEDNESDAY...THE MAIN FORECASTING CHALLENGE CONTINUES TO BE PRECIPITATION CHANCES...AS TIMING AND LOCATION REMAIN PROBLEMATIC GIVEN THE NORTHWESTERLY FLOW. FOR MONDAY NIGHT...MID LEVEL HTS WILL BEGIN TO INCREASE AS HIGH PRESSURE ALOFT BUILDS EAST OF THE DESERT SOUTHWEST. INCREASED MID LEVEL WAA WILL RESULT...LEADING TO INCREASED POPS MONDAY NIGHT INTO EARLY TUESDAY. WILL KEEP POPS AS SLIGHTS ATTM...AS DECENT JET SUPPORT IS FOCUSED EAST OF THE AREA. A SECONDARY AREA OF MID LEVEL WAA WILL TRACK ACROSS THE CWA FROM NW TO SE ON TUESDAY INTO TUESDAY EVENING. WILL HOLD ONTO SLIGHT CHANCES FOR PCPN SINCE THE BEST JET SUPPORT REMAINS EAST OF THE AREA. BY WEDNESDAY AFTERNOON...BOTH THE NAM AND GFS FORCE A DECENT SHORTWAVE INTO WRN NEBRASKA LATE IN THE DAY...LIFTING THIS EAST INTO WEDNESDAY NIGHT. WILL START POPS OFF LOW IN THE WEST...AS BETTER CHANCES WILL ARRIVE WEDNESDAY NIGHT AS THE FORECAST AREA IS IN THE RIGHT REAR QUAD OF THE EXITING JET. LONG RANGE...WEDNESDAY NIGHT THROUGH SUNDAY...ACTIVE WESTERLY AND NORTHWESTERLY FLOW ALOFT WILL CONTINUE ACROSS THE CENTRAL AND NORTHERN PLAINS INTO THE EXTENDED PERIODS. ATTM...THE BEST CHANCES FOR RAIN APPEAR TO LIE ON WEDNESDAY NIGHT AND FRIDAY NIGHT AS THE FORECAST AREA IS IN A FAVORABLE EXIT REGION OF THE H300 JET. HAVE INCREASED POPS INTO THE 50 PERCENT RANGE FOR WEDNESDAY NIGHT AND THURSDAY AND WILL KEEP CHANCE POPS GOING INTO THURSDAY NIGHT. THE EXTENSION OF POPS INTO THURSDAY NIGHT...IS TO ACCOMMODATE THE LATEST ECMWF WHICH IS 12 HRS SLOWER THAN THE LATEST GFS SOLN. TEMPERATURES FOR THE WEEK WILL COOL BACK INTO THE 80S...THANKS TO EXPECTED CLOUD COVER AND SERLY AND ERLY UPSLOPE WINDS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1122 PM CDT SUN JUL 21 2013 THE LATEST CONSENSUS OF THE HRRR...NAM AND RAP MODELS SUGGESTS ISOLATED THUNDERSTORMS WOULD CONTINUE THROUGH ABOUT 12Z MONDAY MORNING AND THEN REDEVELOP BETWEEN 21Z-00Z MONDAY AFTERNOON. GIVEN THE STRONG CAP OPERATING MONDAY AFTN...JUST ISOLATED STORMS WOULD BE EXPECTED GENERALLY FROM KBBW WEST THROUGH KLBF...KIML AND KOGA. STORM ACTIVITY...IF IT DEVELOPS...WOULD EXIT THE FCST AREA BY ROUGHLY 03Z. A THIRD SOUTHEASTWARD MOVING AREA OF THUNDERSTORMS COULD THEN BEGIN AFFECTING NRN NEB AROUND 06Z MONDAY EVENING. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...CDC SYNOPSIS...CLB SHORT TERM...MASEK LONG TERM...CLB AVIATION...CDC
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
810 PM EDT TUE JUL 23 2013 .SYNOPSIS... ADDITIONAL SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL STILL BE POSSIBLE UNTIL A STRONG COLD FRONT PASSES THROUGH OVERNIGHT. MUCH DRIER AND COOLER WEATHER WILL SETTLE IN FOR WEDNESDAY THROUGH FRIDAY COURTESY OF CANADIAN HIGH PRESSURE. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... 730 PM UPDATE... FRONTAL BNDRY IS DROPPING THRU CANADA ATTM. PRE-FRONTAL TROF IS POISED TO CROSS THE GREAT LKS WITH SHOWERS/TSTMS DVLPNG JUST AHD OF IT, IN COMBINATION WITH MCV ROTATING THRU WRN NY. A BROKEN LINE OF CONVECTION IS LOCATED ACRS SRN ONTARIO WELL AHD OF MAIN CDFNT. AS IT STANDS NOW, DO NOT EXPECT THIS LINE OF CONVECTION TO SUSTAIN ITSELF MUCH LONGER WITH LOSS OF DIURNAL HTG AND INSTABILITY ON THE WANE. HWVR, CANNOT RULE OUT SCTD SHOWERS/ISOLD THUNDER AS THIS PRE-FRONTAL TROF/CDFNT MV THRU CWA OVRNGT. LATEST HRRR SHOWS LINE OF CONVECTION CROSSING ACRS SRN SXNS OF CWA OVRNGT TONIGHT BUT AS OF 23Z IT IS NOT EVEN CLOSE TO BEING IN LINE WITH REALITY. THUS, HV DISCOUNTED IT AND HV SIDED MORE WITH HIRES ARW WHICH SHOWS VRY ISOLD CONVECTION THRU THE NIGHT WITH SOME SHOWERS EXPECTED AFT 06Z WITH MAIN COLD FRONT. HV UPDATED SKY GRIDS INITIALLY WITH MOCLDY EXPECTED THRU 02Z ACRS WRN ZONES AND DIMINISHING WITH SUNSET. PCLDY-MOCLDY WL EXIST THRU MOST OF THE NIGHT, ESPECIALLY IN AREAS DOWNWIND OF LK ONTARIO AS MOISTURE GETS TRAPPED UNDER SUBSIDENCE INVERSION AFT 08Z. HV KEPT MENTION OF ISOLD SHOWERS BUT MAY BE LOOKING AT MORE OF A DRIZZLE/FOG SCENARIO UNDER LOW CLD CVR. NO OTHER CHGS MADE TO MINS/WINDS AT THIS TIME AS ALL LOOKS TO BE ON TARGET. PREV DISCUSSION BLO... 230 PM UPDATE... UPPER WAVE EXITED THIS MORNING...TAKING AWAY THE DEEPER MOISTURE WITH IT. HOWEVER...WE STILL HAVE A FEW FEATURES TO DEAL WITH BEFORE HIGH PRESSURE BUILDS IN AND SHUTS THINGS DOWN. LOOSELY- DEFINED SURFACE LOW HAS MOVED TO THE MID HUDSON VALLEY WITH A FRONTAL BOUNDARY /INITIAL COLD FRONT/ DRAGGING BEHIND IT. ASSOCIATED LOW LEVEL CONVERGENCE ZONE HAS YIELDED SCATTERED SHOWERS AND AN OCCASIONAL LIGHTNING STRIKE GENERALLY FROM THE CATSKILLS TO WYOMING VALLEY...NOW SHIFTING SOUTHEAST THROUGH THE POCONOS. ACTIVITY PROBABLY WOULD BE BETTER ORGANIZED IF IT OUR REGION HAD NOT BEEN IN THE UNFAVORABLE LEFT ENTRANCE REGION OF A DEPARTING JET THIS MORNING TO EARLY AFTERNOON. MEANWHILE...SECONDARY STRONG COLD FRONT IS IGNITING CONVECTION IN LOWER MICHIGAN. THIS WILL TRAVEL THROUGH LATE TONIGHT WITH A BATCH OF SCATTERED SHOWERS. AT THIS TIME...FIGURING LOSS OF DIURNAL HEATING AND LOWERING PWATS WILL PROBABLY PREVENT THUNDER AFTER MIDNIGHT...NOT COMPLETELY IMPOSSIBLE BUT SHOULD BE THE EXCEPTION NOT THE RULE. HOWEVER...BETWEEN THE TWO FRONTS...WE HAVE A SHORTWAVE RUNNING OUT AHEAD OF THE SECONDARY FRONT. THIS IS CURRENTLY PRODUCING CONVECTION FROM EASTERN OHIO TO JUST NORTH OF THE WESTERN TIP OF LAKE ONTARIO. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE FIGURED THIS EVENING FROM THIS ACTIVITY...FOR AT LEAST THE NORTHWEST TO CENTRAL PORTIONS OF OUR AREA. WE WILL NEED TO WATCH THE LOCALIZED AREAS THAT RECEIVED HEAVY RAINFALL IN THE LAST 18-24 HOURS JUST IN CASE...BUT AT THIS POINT NOT EXPECTING WATER PROBLEMS BECAUSE OF DECREASING PRECIPITABLE WATER VALUES...LIMITED GAPPY COVERAGE TO THE CONVECTION...AND THE PROGRESSIVE NATURE OF INDIVIDUAL CELLS THIS EVENING INTO OVERNIGHT. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/... 1 PM UPDATE... LONG STORY SHORT...LARGE CANADIAN HIGH PRESSURE BUILDS IN WITH DRY AND COOL AIR MASS. THIS WILL INCLUDE THE COOLEST TEMPERATURES OF JULY 2013 BY EARLY THURSDAY MORNING. ON THE FRONT EDGE OF THE BUILDING HIGH...SOME LOW LEVEL MOISTURE WILL BE TRAPPED UNDER DEVELOPING SUBSIDENCE INVERSION EARLY WEDNESDAY. GIVEN THE FAIRLY SHALLOW NATURE OF IT...EXPECTING CLOUDS AND PERHAPS A COUPLE SPRINKLES FOR A TIME EARLY WEDNESDAY MORNING...BEFORE VERY DRY AIR MASS BECOMES FULLY REALIZED LATE MORNING THROUGH WEDNESDAY AFTERNOON...ERADICATING CLOUDS VIA COLD AIR ADVECTION AND MIXING DOWN OF VERY DRY AIR FROM MID LEVELS. PRECIPITABLE WATER VALUES DIVE TO LESS THAN A HALF INCH BY LATE WEDNESDAY AFTERNOON. THIS IS NEARLY 2 STANDARD DEVIATIONS BELOW NORMAL FOR JULY. EXCEPT FOR PERHAPS THE LOWEST ELEVATIONS OF DELAWARE VALLEY IN PIKE COUNTY PA...HIGHS WEDNESDAY SHOULD BE LIMITED TO UPPER 60S TO MID 70S FOR CNY AND 70S FOR NEPA. THE COOL FRESH DAY WITH NORTHWEST WINDS GUSTING TO 15-20 MPH...WILL BE FOLLOWED BY QUICK DECOUPLING OF WINDS WEDNESDAY NIGHT AS CENTER OF HIGH SHIFTS FROM WESTERN GREAT LAKES TO EASTERN GREAT LAKES/QUEBEC/ONTARIO. RADIATIONAL COOLING WILL EASILY YIELD THE COOLEST NIGHT OF THIS MONTH...UPPER 40S TO MID 50S...COOLEST IN SHELTERED VALLEYS OF THE TWIN TIERS AND WESTERN CATSKILLS AND MOHAWK VALLEY. CAVEAT ON THIS IS THAT WITH 850MB TEMPERATURES OF ONLY 6-8 DEGREES CELSIUS...WE MAY ACTUALLY GET SOME LAKE EFFECT CLOUDS COMING FROM LAKE ONTARIO TO SOME PARTS OF FINGER LAKES AND CENTRAL SOUTHERN TIER REGIONS. TEMPERATURES WILL BE VERY SENSITIVE TO RADIATIONAL COOLING SET UP AND THUS CLOUD LAYER DETAILS. HIGH PRESSURE CENTER WILL TRAVEL ROUGHLY DOWN THE SAINT LAWRENCE SEAWAY THURSDAY...THEN TO CANADIAN MARITIME PROVINCES FRIDAY...YET OVERALL THE HIGH PRESSURE WILL REMAIN DOMINANT OF OUR WEATHER. I WAS ABLE TO REMOVE LINGERING SLIGHT CHANCE OF A SHOWER THAT WAS IN OUR FAR SOUTHEASTERN ZONES THURSDAY. BY FRIDAY...SOME EASTERLY LOW LEVEL FLOW UNDER THE HIGH COULD POTENTIALLY ATTEMPT TO BRING IN MARINE LAYER MOISTURE AGAINST THE POCONOS/CATSKILLS...SO I PLACE A SLIGHT CHANCE OF A SHOWER THERE BUT OTHERWISE STILL DRY AREAWIDE. OVERALL...AT LEAST A SURFACE RIDGE WILL KEEP CONTROL FOR MOST OF THE REGION. HIGHS FRIDAY BACK UP TO NEAR CLIMATOLOGY...YET WITH DEWPOINTS STILL VERY COMFORTABLE IN THE 50S. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... 330 PM EDT UPDATE... THE MAIN FOCUS OF THE EXTENDED FORECAST IS A STRONG UPPER LEVEL LOW MOVING SOUTH FROM CANADA INTO THE CENTRAL PLAINS THURSDAY AND THEN PROPAGATE EASTWARD AND AFFECT THE CWA ON SATURDAY. THE BEST CHANCE FOR SHOWERS AND THUNDERSTORMS WILL BE ON SUNDAY AS FRONT PUSHES THROUGH THE REGION. INCREASED POPS ON SUNDAY AS CONFIDENCE HAS INCREASED. MODELS INDICATE THAT PWAT VALUES WILL INCREASE ABOVE 1.5 INCHES SO HEAVY RAIN ATTENDANT WITH THE FRONT MAY BE POSSIBLE. THE COLD FRONT WILL BRING COOLER TEMPS AND MUCH DRIER AIR TO CENTRAL NY AND NORTHEAST PA. WITH THIS DRIER AIR THERE SHOULD BE A COUPLE OF DRY PERIODS INTO THE NEW WEEK UNTIL ANOTHER SYSTEM PUSHES THROUGH MID WEEK. && .AVIATION /00Z WEDNESDAY THROUGH SUNDAY/... WEAK AREA OF CONVECTION NOW ENTERING THE CENTRAL SOUTHERN TIER WHICH WILL CONTINUE MOVING EASTWARD BEFORE AFFECTING ELM AND ITH BETWEEN 01-02Z...BGM BETWEEN 02-03Z...AND AVP BETWEEN 03-O4Z IF THE COMPLEX ACTUALLY HOLDS TOGETHER. EVALUATION OF UPSTREAM OBS THAT WERE IMPACTED BY THIS ACTIVITY MAINTAINED MOSTLY VFR CONDITIONS AS IT ROLLED THROUGH...THUS EXPECT LIMITED RESTRICTIONS OVER THE NEXT FEW HRS. ADDITIONAL ACTIVITY ACROSS ONEIDA COUNTY THIS HR MAY INFLUENCE RME OVER THE NEXT HALF HR OR SO...OTHERWISE MOSTLY NO IMPACTS EXPECTED IN THE NEAR TERM AT EITHER SYR OR RME. SHIFTING GEARS TO THE OVERNIGHT...FCST GUIDANCE CONTINUES TO SHOW DEVELOPING MVFR CIGS AS FLOW BECOMES MORE NORTHWESTERLY WITH TIME. FOR NOW...EXPECT MVFR CIGS AT MOST TERMINALS AFTER THE 06Z TIME FRAME BEFORE CIGS BEGIN TO SCATTER OUT BETWEEN 15 AND 18Z. OVERALL CONFIDENCE ON IFR CIGS REMAINS IN QUESTION AND HAVE ELECTED TO LEAVE OUT OF THE FCST FOR NOW. WINDS THROUGH THE PERIOD WILL REMAIN OUT OF THE NORTHWEST WITH GUSTS AS HIGH AS 20 KTS POSSIBLE DURING THE DAYLIGHT HRS ON WEDNESDAY. .OUTLOOK... WED AFTERNOON/THU/...VFR FRI/SAT/SUN...CHANCE OF SCATTERED MVFR CIGS/VSBYS IN DEVELOPING SHRA/TSRA ACTIVITY. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...MDP NEAR TERM...MDP/PVN SHORT TERM...MDP LONG TERM...KAH AVIATION...CMG
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
731 PM EDT TUE JUL 23 2013 .SYNOPSIS... ADDITIONAL SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL STILL BE POSSIBLE UNTIL A STRONG COLD FRONT PASSES THROUGH OVERNIGHT. MUCH DRIER AND COOLER WEATHER WILL SETTLE IN FOR WEDNESDAY THROUGH FRIDAY COURTESY OF CANADIAN HIGH PRESSURE. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... 730 PM UPDATE... FRONTAL BNDRY IS DROPPING THRU CANADA ATTM. PRE-FRONTAL TROF IS POISED TO CROSS THE GREAT LKS WITH SHOWERS/TSTMS DVLPNG JUST AHD OF IT, IN COMBINATION WITH MCV ROTATING THRU WRN NY. A BROKEN LINE OF CONVECTION IS LOCATED ACRS SRN ONTARIO WELL AHD OF MAIN CDFNT. AS IT STANDS NOW, DO NOT EXPECT THIS LINE OF CONVECTION TO SUSTAIN ITSELF MUCH LONGER WITH LOSS OF DIURNAL HTG AND INSTABILITY ON THE WANE. HWVR, CANNOT RULE OUT SCTD SHOWERS/ISOLD THUNDER AS THIS PRE-FRONTAL TROF/CDFNT MV THRU CWA OVRNGT. LATEST HRRR SHOWS LINE OF CONVECTION CROSSING ACRS SRN SXNS OF CWA OVRNGT TONIGHT BUT AS OF 23Z IT IS NOT EVEN CLOSE TO BEING IN LINE WITH REALITY. THUS, HV DISCOUNTED IT AND HV SIDED MORE WITH HIRES ARW WHICH SHOWS VRY ISOLD CONVECTION THRU THE NIGHT WITH SOME SHOWERS EXPECTED AFT 06Z WITH MAIN COLD FRONT. HV UPDATED SKY GRIDS INITIALLY WITH MOCLDY EXPECTED THRU 02Z ACRS WRN ZONES AND DIMINISHING WITH SUNSET. PCLDY-MOCLDY WL EXIST THRU MOST OF THE NIGHT, ESPECIALLY IN AREAS DOWNWIND OF LK ONTARIO AS MOISTURE GETS TRAPPED UNDER SUBSIDENCE INVERSION AFT 08Z. HV KEPT MENTION OF ISOLD SHOWERS BUT MAY BE LOOKING AT MORE OF A DRIZZLE/FOG SCENARIO UNDER LOW CLD CVR. NO OTHER CHGS MADE TO MINS/WINDS AT THIS TIME AS ALL LOOKS TO BE ON TARGET. PREV DISCUSSION BLO... 230 PM UPDATE... UPPER WAVE EXITED THIS MORNING...TAKING AWAY THE DEEPER MOISTURE WITH IT. HOWEVER...WE STILL HAVE A FEW FEATURES TO DEAL WITH BEFORE HIGH PRESSURE BUILDS IN AND SHUTS THINGS DOWN. LOOSELY- DEFINED SURFACE LOW HAS MOVED TO THE MID HUDSON VALLEY WITH A FRONTAL BOUNDARY /INITIAL COLD FRONT/ DRAGGING BEHIND IT. ASSOCIATED LOW LEVEL CONVERGENCE ZONE HAS YIELDED SCATTERED SHOWERS AND AN OCCASIONAL LIGHTNING STRIKE GENERALLY FROM THE CATSKILLS TO WYOMING VALLEY...NOW SHIFTING SOUTHEAST THROUGH THE POCONOS. ACTIVITY PROBABLY WOULD BE BETTER ORGANIZED IF IT OUR REGION HAD NOT BEEN IN THE UNFAVORABLE LEFT ENTRANCE REGION OF A DEPARTING JET THIS MORNING TO EARLY AFTERNOON. MEANWHILE...SECONDARY STRONG COLD FRONT IS IGNITING CONVECTION IN LOWER MICHIGAN. THIS WILL TRAVEL THROUGH LATE TONIGHT WITH A BATCH OF SCATTERED SHOWERS. AT THIS TIME...FIGURING LOSS OF DIURNAL HEATING AND LOWERING PWATS WILL PROBABLY PREVENT THUNDER AFTER MIDNIGHT...NOT COMPLETELY IMPOSSIBLE BUT SHOULD BE THE EXCEPTION NOT THE RULE. HOWEVER...BETWEEN THE TWO FRONTS...WE HAVE A SHORTWAVE RUNNING OUT AHEAD OF THE SECONDARY FRONT. THIS IS CURRENTLY PRODUCING CONVECTION FROM EASTERN OHIO TO JUST NORTH OF THE WESTERN TIP OF LAKE ONTARIO. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE FIGURED THIS EVENING FROM THIS ACTIVITY...FOR AT LEAST THE NORTHWEST TO CENTRAL PORTIONS OF OUR AREA. WE WILL NEED TO WATCH THE LOCALIZED AREAS THAT RECEIVED HEAVY RAINFALL IN THE LAST 18-24 HOURS JUST IN CASE...BUT AT THIS POINT NOT EXPECTING WATER PROBLEMS BECAUSE OF DECREASING PRECIPITABLE WATER VALUES...LIMITED GAPPY COVERAGE TO THE CONVECTION...AND THE PROGRESSIVE NATURE OF INDIVIDUAL CELLS THIS EVENING INTO OVERNIGHT. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/... 1 PM UPDATE... LONG STORY SHORT...LARGE CANADIAN HIGH PRESSURE BUILDS IN WITH DRY AND COOL AIR MASS. THIS WILL INCLUDE THE COOLEST TEMPERATURES OF JULY 2013 BY EARLY THURSDAY MORNING. ON THE FRONT EDGE OF THE BUILDING HIGH...SOME LOW LEVEL MOISTURE WILL BE TRAPPED UNDER DEVELOPING SUBSIDENCE INVERSION EARLY WEDNESDAY. GIVEN THE FAIRLY SHALLOW NATURE OF IT...EXPECTING CLOUDS AND PERHAPS A COUPLE SPRINKLES FOR A TIME EARLY WEDNESDAY MORNING...BEFORE VERY DRY AIR MASS BECOMES FULLY REALIZED LATE MORNING THROUGH WEDNESDAY AFTERNOON...ERADICATING CLOUDS VIA COLD AIR ADVECTION AND MIXING DOWN OF VERY DRY AIR FROM MID LEVELS. PRECIPITABLE WATER VALUES DIVE TO LESS THAN A HALF INCH BY LATE WEDNESDAY AFTERNOON. THIS IS NEARLY 2 STANDARD DEVIATIONS BELOW NORMAL FOR JULY. EXCEPT FOR PERHAPS THE LOWEST ELEVATIONS OF DELAWARE VALLEY IN PIKE COUNTY PA...HIGHS WEDNESDAY SHOULD BE LIMITED TO UPPER 60S TO MID 70S FOR CNY AND 70S FOR NEPA. THE COOL FRESH DAY WITH NORTHWEST WINDS GUSTING TO 15-20 MPH...WILL BE FOLLOWED BY QUICK DECOUPLING OF WINDS WEDNESDAY NIGHT AS CENTER OF HIGH SHIFTS FROM WESTERN GREAT LAKES TO EASTERN GREAT LAKES/QUEBEC/ONTARIO. RADIATIONAL COOLING WILL EASILY YIELD THE COOLEST NIGHT OF THIS MONTH...UPPER 40S TO MID 50S...COOLEST IN SHELTERED VALLEYS OF THE TWIN TIERS AND WESTERN CATSKILLS AND MOHAWK VALLEY. CAVEAT ON THIS IS THAT WITH 850MB TEMPERATURES OF ONLY 6-8 DEGREES CELSIUS...WE MAY ACTUALLY GET SOME LAKE EFFECT CLOUDS COMING FROM LAKE ONTARIO TO SOME PARTS OF FINGER LAKES AND CENTRAL SOUTHERN TIER REGIONS. TEMPERATURES WILL BE VERY SENSITIVE TO RADIATIONAL COOLING SET UP AND THUS CLOUD LAYER DETAILS. HIGH PRESSURE CENTER WILL TRAVEL ROUGHLY DOWN THE SAINT LAWRENCE SEAWAY THURSDAY...THEN TO CANADIAN MARITIME PROVINCES FRIDAY...YET OVERALL THE HIGH PRESSURE WILL REMAIN DOMINANT OF OUR WEATHER. I WAS ABLE TO REMOVE LINGERING SLIGHT CHANCE OF A SHOWER THAT WAS IN OUR FAR SOUTHEASTERN ZONES THURSDAY. BY FRIDAY...SOME EASTERLY LOW LEVEL FLOW UNDER THE HIGH COULD POTENTIALLY ATTEMPT TO BRING IN MARINE LAYER MOISTURE AGAINST THE POCONOS/CATSKILLS...SO I PLACE A SLIGHT CHANCE OF A SHOWER THERE BUT OTHERWISE STILL DRY AREAWIDE. OVERALL...AT LEAST A SURFACE RIDGE WILL KEEP CONTROL FOR MOST OF THE REGION. HIGHS FRIDAY BACK UP TO NEAR CLIMATOLOGY...YET WITH DEWPOINTS STILL VERY COMFORTABLE IN THE 50S. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... 330 PM EDT UPDATE... THE MAIN FOCUS OF THE EXTENDED FORECAST IS A STRONG UPPER LEVEL LOW MOVING SOUTH FROM CANADA INTO THE CENTRAL PLAINS THURSDAY AND THEN PROPAGATE EASTWARD AND AFFECT THE CWA ON SATURDAY. THE BEST CHANCE FOR SHOWERS AND THUNDERSTORMS WILL BE ON SUNDAY AS FRONT PUSHES THROUGH THE REGION. INCREASED POPS ON SUNDAY AS CONFIDENCE HAS INCREASED. MODELS INDICATE THAT PWAT VALUES WILL INCREASE ABOVE 1.5 INCHES SO HEAVY RAIN ATTENDANT WITH THE FRONT MAY BE POSSIBLE. THE COLD FRONT WILL BRING COOLER TEMPS AND MUCH DRIER AIR TO CENTRAL NY AND NORTHEAST PA. WITH THIS DRIER AIR THERE SHOULD BE A COUPLE OF DRY PERIODS INTO THE NEW WEEK UNTIL ANOTHER SYSTEM PUSHES THROUGH MID WEEK. && .AVIATION /23Z TUESDAY THROUGH SUNDAY/... 200 PM EDT UPDATE... A VERY CHALLENGING FORECAST FOR THE NEXT 24 HOURS IS AHEAD. A STUBBORN LOW STRATUS DECK HAS LINGERED MUCH LONGER THAN ANTICIPATED THIS MORNING ACROSS CENTRAL NY AND IS SLOWLY LIFTING. EXPECT THIS TO LIFT TO VFR BY 20Z. LIGHT WINDS WILL REMAIN OVER THE ARE THROUGH THE EVENING HOURS. VFR CONDITIONS WILL PREVAIL THROUGH 4Z THIS TONIGHT. A STRONG COLD FRONT WILL MOVE THROUGH THE AREA TONIGHT DROPPING CIGS TO MVFR WITH LIGHT SHOWERS IN ITS WAKE. AS THESE SHOWERS PASS FUEL ALTERNATE CIGS WILL DEVELOP OVER THE REGION AND LAST THROUGH THE LATE MORNING HOURS UNTIL THE DRY AIR MOVES INTO THE REGION. .OUTLOOK... WED AFTERNOON/THU/...VFR FRI/SAT...CHANCE OF SCATTERED MVFR SHRA/TSRA && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...MDP NEAR TERM...MDP/PVN SHORT TERM...MDP LONG TERM...KAH AVIATION...KAH
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
637 PM EDT MON JUL 22 2013 .SYNOPSIS... A TROF OF LOW PRESSURE WILL LINGER INLAND THROUGH TUESDAY. A COLD FRONT WILL SLOWLY PUSH THROUGH WEDNESDAY AND WEDNESDAY NIGHT...BECOMING STATIONARY NEAR THE COAST THURSDAY AND FRIDAY. THE FRONT WILL DISSIPATE ON SATURDAY WITH ANOTHER COLD FRONT APPROACHING FROM THE NORTHWEST MONDAY. && .NEAR TERM /THROUGH TUESDAY/... AS OF 630 PM MONDAY...A DEEP MID-LEVEL TROUGH LIES ACROSS THE TENNESSEE VALLEY WITH HIGH PRESSURE CONTINUE OVER THE CENTRAL ATLANTIC. THIS CONTINUES TO CIRCULATE VERY MOIST AIR INTO EASTERN NORTH CAROLINA AS LATEST MESOANALYSIS GRAPHICS INDICATES PRECIPITABLE WATER VALUES IN EXCESS OF 2 INCHES AREA-WIDE. THE 3 KM HRRR HAS ONCE AGAIN TODAY HAD THE BEST DEPICTION OF THE LOCATION OF PRECIPITATION AND GENERALLY SHOWS ACTIVITY LINGERING ACROSS THE CENTRAL AND WESTERN COASTAL PLAINS FOR A FEW MORE HOURS BEFORE GRADUALLY DISSIPATING LATER TONIGHT AND HAVE SHOWN CHANCE POPS INLAND TO SLIGHT CHANCE COAST THROUGH THE BALANCE OF THE EVENING. MADE NO CHANGES TO CURRENT MINIMUM TEMPERATURE FORECAST WITH LOWS PREDICTED IN THE 72 TO 77 DEGREE RANGE CWA WIDE. && .SHORT TERM /TUESDAY NIGHT THROUGH 6 PM TUESDAY/... AS OF 230 PM MON...TROUGHING INLAND AND HIGH PRESSURE OFF THE SE COAST WILL CONTINUE TUE. SCT CONVECTION EXPECTED AGAIN...MAINLY DIURNAL DRIVEN BY SEABREEZE AND SHORTWAVE APPROACHING FROM THE WEST. FORECAST SOUNDINGS A BIT DRIER THAN PAST SEVERAL DAYS. AN ISOLATED STRONG STORM WILL BE POSSIBLE AS SHEAR INCREASES...WITH GUSTY WINDS...HEAVY RAIN...AND FREQ LIGHTNING. LOW LEVEL THICKNESS VALUES AND TEMPS ALOFT SUPPORT HIGHS IN THE UPPER 80S TO LOWER 90S. && .LONG TERM /TUESDAY NIGHT THROUGH MONDAY/... AS OF 215 PM MON...SIGNIF MDL DIFFERENCES CONT AND LEANED A BIT MORE TWRD ECMWF AND AWAY FROM GFS. UPR TRF WILL DEVELOP TO THE W MID WEEK THEN SWING THRU FRI/FRI NIGHT. ANOTHER PIECE OF ENERGY WILL MOVE THRU THE TRF OVER THE WEEKEND AND SWING N OF THE AREA EARLY NEXT WEEK. WEAK FRONT WILL MOVE INTO THE AREA LATER WED AND DRIFT TO THE CST THU BEFORE STALLING NEAR THE CST FRI INTO SAT. THE INIT FRONT WILL DISSIPATE SUN THEN ANOTHER COLD FRONT ASSOC WITH THE SECOND UPR TRF WILL APPROACH FROM THE W MON. APPEARS MOST OF TUE NIGHT AND WED WILL BE RAIN FREE AS ATMS DRIES A BIT IN WAKE OF SRT WAVE....DID KEEP SLIGHT POPS IN. POPS INCREASE WED NIGHT AND THU WITH FRONT IN THE AREA AND APPROACHING UPR TRF...FOR NOW KEPT POPS IN CHC RANGE...LATER SHIFTS CAN BUMP UP IF MDLS BECOME MORE SIMILAR. SCT CONVECTION WILL CONT FRI WITH THE FRONT STALLED IN THE VCNTY AND UPR TRF CROSSING. LOOKS A BIT DRIER OVER THE WEEKEND AS INIT TRF SHIFTS OFF THE CST. COULD SEE A BIT BETTER CVRG LATER SUN AND MON AS SECOND TRF APPROACH AND PASSES TO THE N. TEMPS WILL REMAIN NEAR NORMAL WED WITH LOWER 90S INLAND AND MID/UPR 80S CST. WITH FRONT IN AREA AND FALLING HGTS EXPECT SLIGHTLY COOLER TEMPS REST OF THE PERIOD WITH HIGHS IN THE 80S. DESPITE POSS OF SOME N/NE WINDS LOOKS LIKE DEWPTS WILL MAINLY STAY AOA 70 KEEPING LOW IN THE 70S AREA-WIDE. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... SHORT TERM /THROUGH TUESDAY/... AS OF 230 PM MON...SCT SHOWERS AND THUNDERSTORMS CONTINUE ACROSS THE CENTRAL CWA. KEWN AND KISO HAVE ALREADY HAD SHOWERS AND KPGV COULD ALSO CATCH A SHOWER IN THE NEXT HOUR OR TWO. EXPECT ACTIVITY TO WANE WITH LOSS OF HEATING. MAIN QUESTION WILL BE IF STRATUS FORMS LATE TONIGHT AND ITS EXTENT. SINCE RAINFALL HAS ALREADY OCCURRED AT KEWN AND KISO AND SHOWERS WILL BE NEAR KPGV FOR THE NEXT COUPLE OF HOURS...WILL HIT THE STRATUS A BIT HARDER AT THESE SPOTS...WITH CEILINGS NOT QUITE AS LOW AT KOAJ. DIURNAL CONVECTION LIKELY AGAIN TUE AFTERNOON/EVENING. SWLY WINDS WILL CONTINUE WITH GUSTS 15-20KT TUE AFTERNOON. LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... AS OF 215 PM MON...WL LIKELY HAVE BOUTS OF LATE NIGHT/EARLY MORN ST/SCU WITH CIGS IN THE MVFR TO IFR RANGE AT TIMES...POSS SOME PATCHY FOG AS WELL. DURING THE DAY/EVENING EXPECT MAINLY VFR...HOWEVER SCT CONVECTION WILL LEAD TO BRIEF PDS OF REDUCED FLIGHT CATEGORIES THRU THE PERIOD. && .MARINE... SHORT TERM /THROUGH TUESDAY/... AS OF 635 PM MON...MODERATE SOUTHWEST WINDS OF 10 TO 20 KNOTS CONTINUE OVER THE COASTAL WATERS AND SOUNDS WITH SEAS GENERALLY 2 TO 4 FEET UP NORTH AND 3 TO 5 FEET SOUTH. ONLY MINOR TWEAKS MADE TO CURRENT MARINE FORECAST. TIGHTENED GRADIENT WILL CONTINUE TUE WITH WINDS 10-20KT AND GUSTS TO 25KT SOUTH OF OREGON INLET...WITH SEAS BUILDING TO 6FT ON THE OUTER WATERS. ISSUED SCA FOR WATERS SOUTH OF OREGON INLET BEGINNING TUE INTO TUE NIGHT. LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... AS OF 215 PM MON...GUSTY SOUTH TO SOUTHWEST WED TUE EVENING WILL DIMINISH INTO WED AS WEAK FRONT DRIFTS INTO THE REGION. SCA WILL CONT MOST CSTL WTRS TUE EVENING THEN SEAS SHLD DROP BELOW 6 FT ALL WTRS BY LATER TUE NIGHT. WIND DIR TOUGH THRU REST OF PD WITH FRONTAL POSITION KEY...LEANED TWRD ECMWF/SREF WITH MAINLY LIGHT ONSHORE FLOW NRN TIER AND LIGHT/VRBL SRN TIER THRU FRI. AS FRONT DISSIPATES SAT WINDS WILL BECOME MORE SRLY. WITH FRONT NEAR CST GRDNT SHLD BE LOOSE WITH LIGHT WINDS WED INTO SAT. SEAS WILL DROP TO 2 TO 4 FEET LATER WED AND STAY IN THE 2 TO 3 FOOT RANGE THU INTO SAT. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...NONE. MARINE...SMALL CRAFT ADVISORY FROM 7 AM TUESDAY TO 7 AM EDT WEDNESDAY FOR AMZ152-154. SMALL CRAFT ADVISORY FROM 11 AM TUESDAY TO 2 AM EDT WEDNESDAY FOR AMZ156-158. && $$ SYNOPSIS...CQD NEAR TERM...CTC SHORT TERM...CQD LONG TERM...RF AVIATION...CTC/RF/CQD MARINE...CTC/RF/CQD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
317 PM EDT MON JUL 22 2013 .SYNOPSIS... AN UPPER LEVEL TROUGH WILL SLOWLY DEEPEN OVER THE EASTERN U.S. THROUGH TUESDAY. AT THE SURFACE...A WEAK BOUNDARY WILL REMAIN OVER CENTRAL NORTH CAROLINA THROUGH WEDNESDAY. && .NEAR TERM /THROUGH TUESDAY NIGHT/... AS OF 250 PM MONDAY... THROUGH TONIGHT: THE LAST FEW HOURS HAVE SEEN INCREASING SUNSHINE AS THE THE MORNING STRATOCUMULUS HAS LARGELY LIFTED AND MIXED OUT... AND A BAND OF CONVECTION HAS FORMED OVER THE HIGHER TERRAIN... WITH ITS CELLS MOVING SLOWLY TO THE NE... ROUGHLY ALONG THE BAND`S AXIS. THE COLUMN HAS DESTABILIZED MODERATELY WITH MUCAPE UP TO 2000 J/KG AND MLCAPE OF 1000-1500 J/KG OVER CENTRAL NC... ALONG WITH LOW LEVEL LAPSE RATES NEAR 7 C/KM... BUT THE DEEP LAYER SHEAR IS WEAK (20 KTS OR LOWER) AND EXPECTED TO REMAIN SO WELL INTO TONIGHT... AND THIS SHOULD LIMIT STORM ORGANIZATION DESPITE THE PERSISTENT HIGH PW OF 2.0-2.2 INCHES. THE POTENT SHORTWAVE TROUGH NOW TRACKING THROUGH THE WRN OH VALLEY... WHICH SPAWNED A PROMINENT CONVECTIVE SYSTEM ALONG THE MO/AR BORDER INTO TN EARLY THIS MORNING... SHOULD APPROACH CENTRAL NC LATER TONIGHT. AHEAD OF THIS WAVE... A WEAKER WAVE ROOTED IN THE UPPER LEVELS MOVING INTO GA (AND HELPING TO FUEL GULF COAST CONVECTION) IS ON PACE TO MOVE ENE ACROSS THE CAROLINAS EARLIER TONIGHT... HOWEVER THIS WAVE SHOULD SLOWLY DAMPEN WITH THE APPROACH OF THE STRONGER WAVE FROM THE WEST. THE CONVECTION ASSOCIATED WITH THIS STRONG WAVE HAS FRACTURED IN THE LAST COUPLE OF HOURS WITH THE COLD POOL RACING SOUTHWARD THROUGH MS/AL (WHILE NEW STORMS DEVELOP TO THE NW ALONG THE NOSE OF THE THETAE RIDGE) WHILE THE STORMS ASSOCIATED WITH THE BETTER WIND FIELD (INCLUDING A 25-30 KT LOW LEVEL JETLET) AND UPPER DIVERGENCE TRACK EASTWARD ACROSS WV TOWARD MD/NRN VA/PA. THE LATEST HRRR REPLICATED THIS FRACTURING QUITE WELL... HOLDING ASSOCIATED PRECIP WEST OF CENTRAL NC THROUGH 06Z... AND ALSO DEPICTS THE CONVECTION NOW ALONG THE NC EAST SLOPES TRANSLATING NE BEFORE PETERING OUT AS IT REACHES THE TRIAD. GIVEN THESE SIGNALS AND OBSERVED TRENDS... EXPECT ISOLATED TO SCATTERED (AT BEST) COVERAGE OF STORMS IN CENTRAL NC THROUGH THIS EVENING... WARRANTING JUST A 20-30% POP. THE SHORTWAVE TROUGH WILL MOVE INTO CENTRAL VA/NC AFTER MIDNIGHT... ACCOMPANIED BY THE 850 MB TROUGH AND A DROP IN PW WITH THE ONSET OF DOWNSLOPE FLOW. MODELS CONTINUE TO SHOW NO DYNAMIC FORCING FOR ASCENT AS THIS WAVE APPROACHES WITH WEAK DPVA WITH THE WEAKENING WIND FIELD... SO DESPITE CONTINUED HIGH DEEP-LAYER MOISTURE IN THE ERN CWA LATE TONIGHT AND LINGERING WEAK ELEVATED INSTABILITY... THE LIFT APPEARS TOO WEAK FOR ANYTHING MORE THAN ISOLATED SHOWERS/STORMS THERE OVERNIGHT GIVEN THE LOW DEEP-LAYER SHEAR. EXPECT LOWS TO FOLLOW CLOSE TO PERSISTENCE... 69-73. FOR TUESDAY/TUESDAY NIGHT: MODELS DEPICT WEAK SUBSIDENCE... FLATTENING AND WEAKENING MID LEVEL FLOW... AND A LOT OF DRYING ABOVE 800 MB IN THE WAKE OF THE SHORTWAVE TROUGH AS IT SHIFTS OFF THE MIDATLANTIC COAST. WEAK SURFACE TROUGHING LINGERS OVER CENTRAL AND ERN NC WHILE 925-850 MB BECOMES UNIFORMLY DOWNSLOPE ACROSS THE AREA FROM THE W AND NW... LIKELY FORCING SOME ADDITIONAL LOW LEVEL DRYING. THE NAM BRINGS MLCAPE UP TO 1000-1500 J/KG AGAIN TUESDAY AFTERNOON OVER CENTRAL NC... HOWEVER ANY CAPE SHOULD BE VERY SKINNY AND YIELD JUST SMALL VERTICAL ACCELERATIONS. MODELS ARE GENERATING VERY LITTLE IF ANY PRECIP... AND WHAT LITTLE DOES DEVELOP IS FOCUSED ALONG/EAST OF INTERSTATE 95. WITH GOOD AGREEMENT FROM SREF PRECIP PROBABILITIES... HAVE TRIMMED BACK POPS TO JUST ISOLATED WEST/CENTRAL AND CHANCE POPS IN THE COASTAL PLAIN WHERE LOW LEVEL MOISTURE AND RESULTANT POTENTIAL INSTABILITY SHOULD BE A BIT BETTER. EXPECT ANY PRECIP CHANCES TO END TOWARD NIGHTFALL. HIGHS 90-94 AS THICKNESSES CLIMB TO ABOUT 5 M ABOVE NORMAL. LOWS 68-72 TUESDAY NIGHT WITH MOSTLY CLEAR SKIES GIVING WAY TO PATCHY STRATUS AND FOG OVERNIGHT. -GIH && .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... AS OF 300 PM MONDAY... A PAIR OF SHORTWAVE TROUGHS ALOFT...BOTH EMBEDDED WITHIN A SHEAR AXIS STRETCHING FROM SOUTH-CENTRAL CANADA TO THE RELATIVELY DATA-SPARSE EASTERN PACIFIC...WILL CROSS THE MIDDLE ATLANTIC AND CAROLINAS THIS PERIOD - SEPARATED BY ABOUT 24 HOURS AND BOTH WITH FAVORABLE DIURNAL TIMING FOR ENHANCED THUNDERSTORM COVERAGE EACH AFTERNOON-EVENING. MEANWHILE AT THE SURFACE...A COLD FRONT STRETCHING FROM THE UPPER MIDWEST TO THE CENTRAL PLAINS THIS AFTERNOON WILL CREST THE APPALACHIANS AND MERGE WITH A LEE TROUGH BY LATE WED...THEN DRIFT SLOWLY SOUTHEASTWARD INTO EASTERN NC BY THU. WED AND WED NIGHT: SCATTERED THUNDERSTORMS ARE ACCORDINGLY EXPECTED TO MAXIMIZE ALONG AND EAST OF THE MERGED SURFACE FRONT/TROUGH...WITH LESSER COVERAGE OVER THE WESTERN PIEDMONT WHERE LOW LEVEL WNW FLOW AND LOWER-MIDDLE 60S SURFACE DEWPOINTS ARE FORECAST TO PREVAIL. PROJECTED 15-25 KTS OF DEEP LAYER SHEAR FAVORS MULTI-CELL CLUSTERS CAPABLE OF KNOCKING DOWN A FEW TREES...AND PRODUCING LOCALLY HEAVY RAIN. SHOWERS AND STORMS ARE APT TO LINGER INTO THE FIRST HALF OF THE NIGHT IN THE COASTAL PLAIN...INVOF THE SURFACE BOUNDARY AND PROBABLE OUTFLOW... BEFORE THE PARENT SHORTWAVE TROUGH AND ASSOCIATED LARGER SCALE FORCING FOR ASCENT LIFT NORTHEAST OF OUR REGION..AND NOCTURNAL COOLING/PRIOR CONVECTIVE OVERTURNING STABILIZES THE ENVIRONMENT. WARM WITH HIGHS 89 TO 94...AND LOWS IN THE UPPER 60S TO LOWER 70S. THU AND THU NIGHT: NWP GUIDANCE HAS TRENDED MORE AMPLIFIED WITH THE SECOND SHORTWAVE TROUGH FOR THU. SO WHILE THE BEST LOW LEVEL CONVERGENCE AND MOISTURE WILL EXIST OVER SOUTHEASTERN NC...LOW LEVEL MOISTURE ON THE COOL SIDE OF THE FRONT - IN STILL RELATIVELY-MOIST NORTHEAST FLOW WITH DEWPOINTS IN THE UPPER 60S - WILL LIKELY PROVE SUPPORTIVE OF SCATTERED TO PERHAPS NUMEROUS STORMS FROM NEAR KMEB TO KGSB...WITH MORE WIDELY SCATTERED DEVELOPMENT TO THE NORTHWEST. COOLER IN THE AFOREMENTIONED POST-FRONTAL NE FLOW...WITH HIGHS RANGING FROM THE LOWER 80S NW PIEDMONT TO UPPER 80S SANDHILLS AND SOUTHERN COASTAL PLAIN. LOWS AGAIN GENERALLY INT HE UPPER 60S TO LOWER 70S. && .LONG TERM /FRIDAY THROUGH MONDAY/... AS OF 315 PM MONDAY... IT STILL APPEARS THAT THE BEGINNING OF THE MEDIUM RANGE (FRI-SAT) WILL FEATURE SHORTWAVE RIDGING AND THE LOWEST PROBABILITY OF PRECIPITATION DURING THE PERIOD...WITH RELATIVE HIGHEST PROBABILITIES (30 PERCENT) OVER THE SOUTHERN TIER...WHERE BOUNDARY LAYER MOISTURE WILL BE HIGHEST INVOF THE OLD...DIFFUSING SURFACE FRONT. HIGHS WITHIN A FEW DEGREES OF 85..AND LOWS IN THE UPPER 60S TO LOWER 70S. THE SECOND HALF OF THE MEDIUM RANGE (SUN-MON) WILL FEATURE RENEWED TROUGH AMPLIFICATION ALOFT...AND THE ARRIVAL OF AN ACCOMPANYING SURFACE FRONTAL ZONE INTO THE EASTERN US. MOIST AND PERTURBED SOUTHWEST FLOW ALOFT...IN A REGION OF PERSISTENT UPPER DIVERGENCE IN THE ENTRANCE REGION OF AN ACCOMPANYING UPPER JET AND WITH LOW LEVEL CONVERGENCE ALONG THE SLOWLY-PASSING SURFACE FRONT...FAVOR A GOOD TO LIKELY CHANCE OF SHOWERS AND STORMS MAXIMIZED WITH DIURNAL HEATING. NEARLY PERSISTENCE TEMPERATURES WITHIN A FEW DEGREES OF 85...AND UPPER 60S TO LOWER 70S. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... AS OF 1230 PM MONDAY... MVFR CIGS SEEN THIS MORNING AT ALL CENTRAL NC TAF SITES HAVE FINALLY BEGUN TO BREAK UP... WITH CLOUDS BASED 2-3 KFT NOW VARYING BETWEEN SCT AND BKN. THESE CLOUDS WILL CONTINUE TO SLOWLY LIFT AND MIX OUT... BECOMING PREVAILING VFR AT ALL SITES BY 20Z. OTHERWISE... SCATTERED SHOWERS/STORMS ARE EXPECTED ACROSS CENTRAL NC (FORMING FIRST IN THE WEST NEAR INT/GSO... WITH EVENTUALLY MORE COVERAGE EXPECTED IN THE EAST NEAR RDU/RWI/FAY) BETWEEN 19Z AND 02Z... BUT THE LIMITED COVERAGE AND LOW CONFIDENCE IN TIMING PRECLUDES MENTIONING THUNDER OR SUB-VFR VSBY/CLOUDS AS A PREVAILING CONDITION DURING THIS TIME FRAME. A PERIOD OF VFR CONDITIONS IS EXPECTED 02Z-07Z AT ALL SITES... THEN MVFR TO IFR STRATOCUMULUS IS EXPECTED TO REDEVELOP (ESPECIALLY AT RDU/RWI/FAY) AFTER 07Z TONIGHT. THESE CLOUDS SHOULD SLOWLY LIFT TO VFR BY 16Z TUESDAY. WINDS WILL REMAIN LIGHT THROUGH THIS FORECAST PERIOD... MAINLY FROM THE SW SHIFTING A BIT TO WSW... AT SPEEDS OF 10 KTS OR LESS... 5 KTS OR LESS AT NIGHT. LOOKING BEYOND 18Z TUESDAY... VFR CONDITIONS SHOULD DOMINATE THROUGH WEDNESDAY MORNING WITH GENERALLY DRY WEATHER... ALTHOUGH BRIEF MVFR FOG IS EXPECTED AROUND 08Z-13Z EARLY WEDNESDAY MORNING. SHOWERS/ STORMS WITH A PERIOD OF MVFR CONDITIONS IS POSSIBLE WEDNESDAY AFTERNOON AND EVENING. EARLY MORNING SUB-VFR CONDITIONS ARE ANTICIPATED EACH MORNING THURSDAY THROUGH SATURDAY. -GIH && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...WSS NEAR TERM...HARTFIELD SHORT TERM...MWS LONG TERM...MWS AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
304PM EDT MON JUL 22 2013 .SYNOPSIS... AN UPPER LEVEL TROUGH WILL SLOWLY DEEPEN OVER THE EASTERN U.S. THROUGH TUESDAY. AT THE SURFACE...A WEAK BOUNDARY WILL REMAIN OVER CENTRAL NORTH CAROLINA THROUGH WEDNESDAY. && .NEAR TERM /THROUGH TUESDAY NIGHT/... AS OF 250 PM MONDAY... THROUGH TONIGHT: THE LAST FEW HOURS HAVE SEEN INCREASING SUNSHINE AS THE THE MORNING STRATOCUMULUS HAS LARGELY LIFTED AND MIXED OUT... AND A BAND OF CONVECTION HAS FORMED OVER THE HIGHER TERRAIN... WITH ITS CELLS MOVING SLOWLY TO THE NE... ROUGHLY ALONG THE BAND`S AXIS. THE COLUMN HAS DESTABILIZED MODERATELY WITH MUCAPE UP TO 2000 J/KG AND MLCAPE OF 1000-1500 J/KG OVER CENTRAL NC... ALONG WITH LOW LEVEL LAPSE RATES NEAR 7 C/KM... BUT THE DEEP LAYER SHEAR IS WEAK (20 KTS OR LOWER) AND EXPECTED TO REMAIN SO WELL INTO TONIGHT... AND THIS SHOULD LIMIT STORM ORGANIZATION DESPITE THE PERSISTENT HIGH PW OF 2.0-2.2 INCHES. THE POTENT SHORTWAVE TROUGH NOW TRACKING THROUGH THE WRN OH VALLEY... WHICH SPAWNED A PROMINENT CONVECTIVE SYSTEM ALONG THE MO/AR BORDER INTO TN EARLY THIS MORNING... SHOULD APPROACH CENTRAL NC LATER TONIGHT. AHEAD OF THIS WAVE... A WEAKER WAVE ROOTED IN THE UPPER LEVELS MOVING INTO GA (AND HELPING TO FUEL GULF COAST CONVECTION) IS ON PACE TO MOVE ENE ACROSS THE CAROLINAS EARLIER TONIGHT... HOWEVER THIS WAVE SHOULD SLOWLY DAMPEN WITH THE APPROACH OF THE STRONGER WAVE FROM THE WEST. THE CONVECTION ASSOCIATED WITH THIS STRONG WAVE HAS FRACTURED IN THE LAST COUPLE OF HOURS WITH THE COLD POOL RACING SOUTHWARD THROUGH MS/AL (WHILE NEW STORMS DEVELOP TO THE NW ALONG THE NOSE OF THE THETAE RIDGE) WHILE THE STORMS ASSOCIATED WITH THE BETTER WIND FIELD (INCLUDING A 25-30 KT LOW LEVEL JETLET) AND UPPER DIVERGENCE TRACK EASTWARD ACROSS WV TOWARD MD/NRN VA/PA. THE LATEST HRRR REPLICATED THIS FRACTURING QUITE WELL... HOLDING ASSOCIATED PRECIP WEST OF CENTRAL NC THROUGH 06Z... AND ALSO DEPICTS THE CONVECTION NOW ALONG THE NC EAST SLOPES TRANSLATING NE BEFORE PETERING OUT AS IT REACHES THE TRIAD. GIVEN THESE SIGNALS AND OBSERVED TRENDS... EXPECT ISOLATED TO SCATTERED (AT BEST) COVERAGE OF STORMS IN CENTRAL NC THROUGH THIS EVENING... WARRANTING JUST A 20-30% POP. THE SHORTWAVE TROUGH WILL MOVE INTO CENTRAL VA/NC AFTER MIDNIGHT... ACCOMPANIED BY THE 850 MB TROUGH AND A DROP IN PW WITH THE ONSET OF DOWNSLOPE FLOW. MODELS CONTINUE TO SHOW NO DYNAMIC FORCING FOR ASCENT AS THIS WAVE APPROACHES WITH WEAK DPVA WITH THE WEAKENING WIND FIELD... SO DESPITE CONTINUED HIGH DEEP-LAYER MOISTURE IN THE ERN CWA LATE TONIGHT AND LINGERING WEAK ELEVATED INSTABILITY... THE LIFT APPEARS TOO WEAK FOR ANYTHING MORE THAN ISOLATED SHOWERS/STORMS THERE OVERNIGHT GIVEN THE LOW DEEP-LAYER SHEAR. EXPECT LOWS TO FOLLOW CLOSE TO PERSISTENCE... 69-73. FOR TUESDAY/TUESDAY NIGHT: MODELS DEPICT WEAK SUBSIDENCE... FLATTENING AND WEAKENING MID LEVEL FLOW... AND A LOT OF DRYING ABOVE 800 MB IN THE WAKE OF THE SHORTWAVE TROUGH AS IT SHIFTS OFF THE MIDATLANTIC COAST. WEAK SURFACE TROUGHING LINGERS OVER CENTRAL AND ERN NC WHILE 925-850 MB BECOMES UNIFORMLY DOWNSLOPE ACROSS THE AREA FROM THE W AND NW... LIKELY FORCING SOME ADDITIONAL LOW LEVEL DRYING. THE NAM BRINGS MLCAPE UP TO 1000-1500 J/KG AGAIN TUESDAY AFTERNOON OVER CENTRAL NC... HOWEVER ANY CAPE SHOULD BE VERY SKINNY AND YIELD JUST SMALL VERTICAL ACCELERATIONS. MODELS ARE GENERATING VERY LITTLE IF ANY PRECIP... AND WHAT LITTLE DOES DEVELOP IS FOCUSED ALONG/EAST OF INTERSTATE 95. WITH GOOD AGREEMENT FROM SREF PRECIP PROBABILITIES... HAVE TRIMMED BACK POPS TO JUST ISOLATED WEST/CENTRAL AND CHANCE POPS IN THE COASTAL PLAIN WHERE LOW LEVEL MOISTURE AND RESULTANT POTENTIAL INSTABILITY SHOULD BE A BIT BETTER. EXPECT ANY PRECIP CHANCES TO END TOWARD NIGHTFALL. HIGHS 90-94 AS THICKNESSES CLIMB TO ABOUT 5 M ABOVE NORMAL. LOWS 68-72 TUESDAY NIGHT WITH MOSTLY CLEAR SKIES GIVING WAY TO PATCHY STRATUS AND FOG OVERNIGHT. -GIH && .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... AS OF 300 PM MONDAY... A PAIR OF SHORTWAVE TROUGHS ALOFT...BOTH EMBEDDED WITHIN A SHEAR AXIS STRETCHING FROM SOUTH-CENTRAL CANADA TO THE RELATIVELY DATA-SPARSE EASTERN PACIFIC...WILL CROSS THE MIDDLE ATLANTIC AND CAROLINAS THIS PERIOD - SEPARATED BY ABOUT 24 HOURS AND BOTH WITH FAVORABLE DIURNAL TIMING FOR ENHANCED THUNDERSTORM COVERAGE EACH AFTERNOON-EVENING. MEANWHILE AT THE SURFACE...A COLD FRONT STRETCHING FROM THE UPPER MIDWEST TO THE CENTRAL PLAINS THIS AFTERNOON WILL CREST THE APPALACHIANS AND MERGE WITH A LEE TROUGH BY LATE WED...THEN DRIFT SLOWLY SOUTHEASTWARD INTO EASTERN NC BY THU. WED AND WED NIGHT: SCATTERED THUNDERSTORMS ARE ACCORDINGLY EXPECTED TO MAXIMIZE ALONG AND EAST OF THE MERGED SURFACE FRONT/TROUGH...WITH LESSER COVERAGE OVER THE WESTERN PIEDMONT WHERE LOW LEVEL WNW FLOW AND LOWER-MIDDLE 60S SURFACE DEWPOINTS ARE FORECAST TO PREVAIL. PROJECTED 15-25 KTS OF DEEP LAYER SHEAR FAVORS MULTI-CELL CLUSTERS CAPABLE OF KNOCKING DOWN A FEW TREES...AND PRODUCING LOCALLY HEAVY RAIN. SHOWERS AND STORMS ARE APT TO LINGER INTO THE FIRST HALF OF THE NIGHT IN THE COASTAL PLAIN...INVOF THE SURFACE BOUNDARY AND PROBABLE OUTFLOW... BEFORE THE PARENT SHORTWAVE TROUGH AND ASSOCIATED LARGER SCALE FORCING FOR ASCENT LIFT NORTHEAST OF OUR REGION..AND NOCTURNAL COOLING/PRIOR CONVECTIVE OVERTURNING STABILIZES THE ENVIRONMENT. WARM WITH HIGHS 89 TO 94...AND LOWS IN THE UPPER 60S TO LOWER 70S. THU AND THU NIGHT: NWP GUIDANCE HAS TRENDED MORE AMPLIFIED WITH THE SECOND SHORTWAVE TROUGH FOR THU. SO WHILE THE BEST LOW LEVEL CONVERGENCE AND MOISTURE WILL EXIST OVER SOUTHEASTERN NC...LOW LEVEL MOISTURE ON THE COOL SIDE OF THE FRONT - IN STILL RELATIVELY-MOIST NORTHEAST FLOW WITH DEWPOINTS IN THE UPPER 60S - WILL LIKELY PROVE SUPPORTIVE OF SCATTERED TO PERHAPS NUMEROUS STORMS FROM NEAR KMEB TO KGSB...WITH MORE WIDELY SCATTERED DEVELOPMENT TO THE NORTHWEST. COOLER IN THE AFOREMENTIONED POST-FRONTAL NE FLOW...WITH HIGHS RANGING FROM THE LOWER 80S NW PIEDMONT TO UPPER 80S SANDHILLS AND SOUTHERN COASTAL PLAIN. LOWS AGAIN GENERALLY INT HE UPPER 60S TO LOWER 70S. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... AS OF 300 AM MONDAY... WEDNESDAY THROUGH THURSDAY: THE MEAN TROUGH IN PLACE OVER THE EASTERN US WILL CONTINUE TO UNDERGO GRADUAL AMPLIFICATION WEDNESDAY AND THURSDAY AS A SERIES OF LOW AMPLITUDE SHORT WAVES ROUND THE BASE OF TROUGH AND MOVE ACROSS THE REGION. THE QUASI-STATIONARY SURFACE FRONT ACROSS EASTERN NORTH CAROLINA WILL SAG SLOWLY SOUTH AND EAST OF THE AREA BY WEDNESDAY NIGHT OR THURSDAY AS WEAK SURFACE HIGH PRESSURE OVER THE OHIO VALLEY BUILDS EAST-SOUTHEASTWARD INTO THE NORTHEAST AND MID-ATLANTIC STATES. DPVA ASSOCIATED WITH SHORTWAVE ENERGY MOVING THROUGH THE AREA WITHIN THE CONTINUED MOIST AND UNSTABLE AIRMASS WILL SUPPORT A CONTINUATION OF MOSTLY DIURNAL SHOWERS AND THUNDERSTORM BOTH DAYS. EXPECT THE HIGHEST POPS ACROSS CENTRAL AND EASTERN PORTIONS OF THE PIEDMONT AND COASTAL PLAIN COUNTIES ON WEDNESDAY IN PROXIMITY TO THE SURFACE FRONT AND DEEPER MOISTURE. THERE SHOULD BE CONSIDERABLY LESS COVERAGE ON THURSDAY...ESPECIALLY ACROSS THE WESTERN AND CENTRAL PIEDMONT WITH THE ADVECTION OF DRIER AIR FROM THE NW. A FEW STRONG TO SEVERE STORMS WILL BE POSSIBLE MAINLY ACROSS CENTRAL AND EASTERN NC. NEAR NORMAL TEMPERATURES WITH HIGHS IN THE UPPER 80S NW TO LOWER 90S SE. LOWS IN THE UPPER 60S NW TO LOWER 70S SE. FRIDAY THROUGH SUNDAY: FRIDAY AND POSSIBLY SATURDAY COULD END BEING CONVECTION FREE... WITH THE FRONT STALLED SOUTH OF THE AREA AND VOID OF ANY UPPER LEVEL DISTURBANCES TRACKING INTO THE AREA IN THE WEST-NORTHWESTERLY FLOW ALOFT AS THE BROAD TROUGH WILL BE IN THE PROCESS OF RELOADING. ADDITIONALLY...CENTRAL NC COULD SEE A BRIEF REPRIEVE FROM THE SUMMERTIME HUMIDITY WITH DEWPOINTS FALLING INTO THE MID 60S IN THE LOW-LEVEL NORTH-NORTHEASTERLY FEED AROUND THE SURFACE RIDGE AXIS EXTENDING DOWN THE MID-ATLANTIC SEABOARD. HIGHS 85 TO 90. LOWS 65 TO 70. TIMING REMAINS IN QUESTION WITH THE NEXT SHORTWAVE TROUGH AND ASSOCIATED COLD FRONT INTO THE AREA FROM THE WEST LATE SATURDAY NIGHT THROUGH SUNDAY. FOR NOW WILL CARRY CLIMATOLOGY POPS OF 20 TO 30 PERCENT. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... AS OF 1230 PM MONDAY... MVFR CIGS SEEN THIS MORNING AT ALL CENTRAL NC TAF SITES HAVE FINALLY BEGUN TO BREAK UP... WITH CLOUDS BASED 2-3 KFT NOW VARYING BETWEEN SCT AND BKN. THESE CLOUDS WILL CONTINUE TO SLOWLY LIFT AND MIX OUT... BECOMING PREVAILING VFR AT ALL SITES BY 20Z. OTHERWISE... SCATTERED SHOWERS/STORMS ARE EXPECTED ACROSS CENTRAL NC (FORMING FIRST IN THE WEST NEAR INT/GSO... WITH EVENTUALLY MORE COVERAGE EXPECTED IN THE EAST NEAR RDU/RWI/FAY) BETWEEN 19Z AND 02Z... BUT THE LIMITED COVERAGE AND LOW CONFIDENCE IN TIMING PRECLUDES MENTIONING THUNDER OR SUB-VFR VSBY/CLOUDS AS A PREVAILING CONDITION DURING THIS TIME FRAME. A PERIOD OF VFR CONDITIONS IS EXPECTED 02Z-07Z AT ALL SITES... THEN MVFR TO IFR STRATOCUMULUS IS EXPECTED TO REDEVELOP (ESPECIALLY AT RDU/RWI/FAY) AFTER 07Z TONIGHT. THESE CLOUDS SHOULD SLOWLY LIFT TO VFR BY 16Z TUESDAY. WINDS WILL REMAIN LIGHT THROUGH THIS FORECAST PERIOD... MAINLY FROM THE SW SHIFTING A BIT TO WSW... AT SPEEDS OF 10 KTS OR LESS... 5 KTS OR LESS AT NIGHT. LOOKING BEYOND 18Z TUESDAY... VFR CONDITIONS SHOULD DOMINATE THROUGH WEDNESDAY MORNING WITH GENERALLY DRY WEATHER... ALTHOUGH BRIEF MVFR FOG IS EXPECTED AROUND 08Z-13Z EARLY WEDNESDAY MORNING. SHOWERS/ STORMS WITH A PERIOD OF MVFR CONDITIONS IS POSSIBLE WEDNESDAY AFTERNOON AND EVENING. EARLY MORNING SUB-VFR CONDITIONS ARE ANTICIPATED EACH MORNING THURSDAY THROUGH SATURDAY. -GIH && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...WSS NEAR TERM...HARTFIELD SHORT TERM...MWS LONG TERM...CBL AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
253 PM EDT MON JUL 22 2013 .SYNOPSIS... AN UPPER LEVEL TROUGH WILL SLOWLY DEEPEN OVER THE EASTERN U.S. THROUGH TUESDAY. AT THE SURFACE...A WEAK BOUNDARY WILL REMAIN OVER CENTRAL NORTH CAROLINA THROUGH WEDNESDAY. && .NEAR TERM /THROUGH TUESDAY NIGHT/... AS OF 250 PM MONDAY... THROUGH TONIGHT: THE LAST FEW HOURS HAVE SEEN INCREASING SUNSHINE AS THE THE MORNING STRATOCUMULUS HAS LARGELY LIFTED AND MIXED OUT... AND A BAND OF CONVECTION HAS FORMED OVER THE HIGHER TERRAIN... WITH ITS CELLS MOVING SLOWLY TO THE NE... ROUGHLY ALONG THE BAND`S AXIS. THE COLUMN HAS DESTABILIZED MODERATELY WITH MUCAPE UP TO 2000 J/KG AND MLCAPE OF 1000-1500 J/KG OVER CENTRAL NC... ALONG WITH LOW LEVEL LAPSE RATES NEAR 7 C/KM... BUT THE DEEP LAYER SHEAR IS WEAK (20 KTS OR LOWER) AND EXPECTED TO REMAIN SO WELL INTO TONIGHT... AND THIS SHOULD LIMIT STORM ORGANIZATION DESPITE THE PERSISTENT HIGH PW OF 2.0-2.2 INCHES. THE POTENT SHORTWAVE TROUGH NOW TRACKING THROUGH THE WRN OH VALLEY... WHICH SPAWNED A PROMINENT CONVECTIVE SYSTEM ALONG THE MO/AR BORDER INTO TN EARLY THIS MORNING... SHOULD APPROACH CENTRAL NC LATER TONIGHT. AHEAD OF THIS WAVE... A WEAKER WAVE ROOTED IN THE UPPER LEVELS MOVING INTO GA (AND HELPING TO FUEL GULF COAST CONVECTION) IS ON PACE TO MOVE ENE ACROSS THE CAROLINAS EARLIER TONIGHT... HOWEVER THIS WAVE SHOULD SLOWLY DAMPEN WITH THE APPROACH OF THE STRONGER WAVE FROM THE WEST. THE CONVECTION ASSOCIATED WITH THIS STRONG WAVE HAS FRACTURED IN THE LAST COUPLE OF HOURS WITH THE COLD POOL RACING SOUTHWARD THROUGH MS/AL (WHILE NEW STORMS DEVELOP TO THE NW ALONG THE NOSE OF THE THETAE RIDGE) WHILE THE STORMS ASSOCIATED WITH THE BETTER WIND FIELD (INCLUDING A 25-30 KT LOW LEVEL JETLET) AND UPPER DIVERGENCE TRACK EASTWARD ACROSS WV TOWARD MD/NRN VA/PA. THE LATEST HRRR REPLICATED THIS FRACTURING QUITE WELL... HOLDING ASSOCIATED PRECIP WEST OF CENTRAL NC THROUGH 06Z... AND ALSO DEPICTS THE CONVECTION NOW ALONG THE NC EAST SLOPES TRANSLATING NE BEFORE PETERING OUT AS IT REACHES THE TRIAD. GIVEN THESE SIGNALS AND OBSERVED TRENDS... EXPECT ISOLATED TO SCATTERED (AT BEST) COVERAGE OF STORMS IN CENTRAL NC THROUGH THIS EVENING... WARRANTING JUST A 20-30% POP. THE SHORTWAVE TROUGH WILL MOVE INTO CENTRAL VA/NC AFTER MIDNIGHT... ACCOMPANIED BY THE 850 MB TROUGH AND A DROP IN PW WITH THE ONSET OF DOWNSLOPE FLOW. MODELS CONTINUE TO SHOW NO DYNAMIC FORCING FOR ASCENT AS THIS WAVE APPROACHES WITH WEAK DPVA WITH THE WEAKENING WIND FIELD... SO DESPITE CONTINUED HIGH DEEP-LAYER MOISTURE IN THE ERN CWA LATE TONIGHT AND LINGERING WEAK ELEVATED INSTABILITY... THE LIFT APPEARS TOO WEAK FOR ANYTHING MORE THAN ISOLATED SHOWERS/STORMS THERE OVERNIGHT GIVEN THE LOW DEEP-LAYER SHEAR. EXPECT LOWS TO FOLLOW CLOSE TO PERSISTENCE... 69-73. FOR TUESDAY/TUESDAY NIGHT: MODELS DEPICT WEAK SUBSIDENCE... FLATTENING AND WEAKENING MID LEVEL FLOW... AND A LOT OF DRYING ABOVE 800 MB IN THE WAKE OF THE SHORTWAVE TROUGH AS IT SHIFTS OFF THE MIDATLANTIC COAST. WEAK SURFACE TROUGHING LINGERS OVER CENTRAL AND ERN NC WHILE 925-850 MB BECOMES UNIFORMLY DOWNSLOPE ACROSS THE AREA FROM THE W AND NW... LIKELY FORCING SOME ADDITIONAL LOW LEVEL DRYING. THE NAM BRINGS MLCAPE UP TO 1000-1500 J/KG AGAIN TUESDAY AFTERNOON OVER CENTRAL NC... HOWEVER ANY CAPE SHOULD BE VERY SKINNY AND YIELD JUST SMALL VERTICAL ACCELERATIONS. MODELS ARE GENERATING VERY LITTLE IF ANY PRECIP... AND WHAT LITTLE DOES DEVELOP IS FOCUSED ALONG/EAST OF INTERSTATE 95. WITH GOOD AGREEMENT FROM SREF PRECIP PROBABILITIES... HAVE TRIMMED BACK POPS TO JUST ISOLATED WEST/CENTRAL AND CHANCE POPS IN THE COASTAL PLAIN WHERE LOW LEVEL MOISTURE AND RESULTANT POTENTIAL INSTABILITY SHOULD BE A BIT BETTER. EXPECT ANY PRECIP CHANCES TO END TOWARD NIGHTFALL. HIGHS 90-94 AS THICKNESSES CLIMB TO ABOUT 5 M ABOVE NORMAL. LOWS 68-72 TUESDAY NIGHT WITH MOSTLY CLEAR SKIES GIVING WAY TO PATCHY STRATUS AND FOG OVERNIGHT. -GIH && .SHORT TERM / /... AS OF 300 AM MONDAY... TO BE UPDATED SHORTLY. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... AS OF 300 AM MONDAY... WEDNESDAY THROUGH THURSDAY: THE MEAN TROUGH IN PLACE OVER THE EASTERN US WILL CONTINUE TO UNDERGO GRADUAL AMPLIFICATION WEDNESDAY AND THURSDAY AS A SERIES OF LOW AMPLITUDE SHORT WAVES ROUND THE BASE OF TROUGH AND MOVE ACROSS THE REGION. THE QUASI-STATIONARY SURFACE FRONT ACROSS EASTERN NORTH CAROLINA WILL SAG SLOWLY SOUTH AND EAST OF THE AREA BY WEDNESDAY NIGHT OR THURSDAY AS WEAK SURFACE HIGH PRESSURE OVER THE OHIO VALLEY BUILDS EAST-SOUTHEASTWARD INTO THE NORTHEAST AND MID-ATLANTIC STATES. DPVA ASSOCIATED WITH SHORTWAVE ENERGY MOVING THROUGH THE AREA WITHIN THE CONTINUED MOIST AND UNSTABLE AIRMASS WILL SUPPORT A CONTINUATION OF MOSTLY DIURNAL SHOWERS AND THUNDERSTORM BOTH DAYS. EXPECT THE HIGHEST POPS ACROSS CENTRAL AND EASTERN PORTIONS OF THE PIEDMONT AND COASTAL PLAIN COUNTIES ON WEDNESDAY IN PROXIMITY TO THE SURFACE FRONT AND DEEPER MOISTURE. THERE SHOULD BE CONSIDERABLY LESS COVERAGE ON THURSDAY...ESPECIALLY ACROSS THE WESTERN AND CENTRAL PIEDMONT WITH THE ADVECTION OF DRIER AIR FROM THE NW. A FEW STRONG TO SEVERE STORMS WILL BE POSSIBLE MAINLY ACROSS CENTRAL AND EASTERN NC. NEAR NORMAL TEMPERATURES WITH HIGHS IN THE UPPER 80S NW TO LOWER 90S SE. LOWS IN THE UPPER 60S NW TO LOWER 70S SE. FRIDAY THROUGH SUNDAY: FRIDAY AND POSSIBLY SATURDAY COULD END BEING CONVECTION FREE... WITH THE FRONT STALLED SOUTH OF THE AREA AND VOID OF ANY UPPER LEVEL DISTURBANCES TRACKING INTO THE AREA IN THE WEST-NORTHWESTERLY FLOW ALOFT AS THE BROAD TROUGH WILL BE IN THE PROCESS OF RELOADING. ADDITIONALLY...CENTRAL NC COULD SEE A BRIEF REPRIEVE FROM THE SUMMERTIME HUMIDITY WITH DEWPOINTS FALLING INTO THE MID 60S IN THE LOW-LEVEL NORTH-NORTHEASTERLY FEED AROUND THE SURFACE RIDGE AXIS EXTENDING DOWN THE MID-ATLANTIC SEABOARD. HIGHS 85 TO 90. LOWS 65 TO 70. TIMING REMAINS IN QUESTION WITH THE NEXT SHORTWAVE TROUGH AND ASSOCIATED COLD FRONT INTO THE AREA FROM THE WEST LATE SATURDAY NIGHT THROUGH SUNDAY. FOR NOW WILL CARRY CLIMATOLOGY POPS OF 20 TO 30 PERCENT. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... AS OF 1230 PM MONDAY... MVFR CIGS SEEN THIS MORNING AT ALL CENTRAL NC TAF SITES HAVE FINALLY BEGUN TO BREAK UP... WITH CLOUDS BASED 2-3 KFT NOW VARYING BETWEEN SCT AND BKN. THESE CLOUDS WILL CONTINUE TO SLOWLY LIFT AND MIX OUT... BECOMING PREVAILING VFR AT ALL SITES BY 20Z. OTHERWISE... SCATTERED SHOWERS/STORMS ARE EXPECTED ACROSS CENTRAL NC (FORMING FIRST IN THE WEST NEAR INT/GSO... WITH EVENTUALLY MORE COVERAGE EXPECTED IN THE EAST NEAR RDU/RWI/FAY) BETWEEN 19Z AND 02Z... BUT THE LIMITED COVERAGE AND LOW CONFIDENCE IN TIMING PRECLUDES MENTIONING THUNDER OR SUB-VFR VSBY/CLOUDS AS A PREVAILING CONDITION DURING THIS TIME FRAME. A PERIOD OF VFR CONDITIONS IS EXPECTED 02Z-07Z AT ALL SITES... THEN MVFR TO IFR STRATOCUMULUS IS EXPECTED TO REDEVELOP (ESPECIALLY AT RDU/RWI/FAY) AFTER 07Z TONIGHT. THESE CLOUDS SHOULD SLOWLY LIFT TO VFR BY 16Z TUESDAY. WINDS WILL REMAIN LIGHT THROUGH THIS FORECAST PERIOD... MAINLY FROM THE SW SHIFTING A BIT TO WSW... AT SPEEDS OF 10 KTS OR LESS... 5 KTS OR LESS AT NIGHT. LOOKING BEYOND 18Z TUESDAY... VFR CONDITIONS SHOULD DOMINATE THROUGH WEDNESDAY MORNING WITH GENERALLY DRY WEATHER... ALTHOUGH BRIEF MVFR FOG IS EXPECTED AROUND 08Z-13Z EARLY WEDNESDAY MORNING. SHOWERS/ STORMS WITH A PERIOD OF MVFR CONDITIONS IS POSSIBLE WEDNESDAY AFTERNOON AND EVENING. EARLY MORNING SUB-VFR CONDITIONS ARE ANTICIPATED EACH MORNING THURSDAY THROUGH SATURDAY. -GIH && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...WSS NEAR TERM...HARTFIELD SHORT TERM...WSS LONG TERM...CBL AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1230 PM EDT MON JUL 22 2013 .SYNOPSIS... AN UPPER LEVEL TROUGH WILL SLOWLY DEEPEN OVER THE EASTERN U.S. THROUGH TUESDAY. AT THE SURFACE...A WEAK BOUNDARY WILL REMAIN OVER CENTRAL NORTH CAROLINA THROUGH WEDNESDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1015 AM MONDAY... REST OF TODAY: VERY MOIST AIR MASS IN PLACE AS NOTED BY 12Z GSO/MHX SOUNDINGS AND BLENDED TPW IMAGERY... WITH PW RANGING FROM 2.0-2.2 INCHES WEST TO EAST... ALTHOUGH VALUES ARE SLIGHTLY LOWER TO OUR WEST. LATEST SURFACE ANALYSIS SHOWS THE NEARLY STATIONARY SYNOPTIC FRONTAL ZONE FROM IA EAST ACROSS NRN IL/IN/OH TO PA/MA. A WEAK LOW IS EVIDENT OVER SCENTRAL VA WITH TRAILING WEAK TROUGHING THROUGH CENTRAL NC... AND A MORE PROMINENT LOW AND TROUGH OVER SRN IL/SE MO/NW AR. THE LATTER FEATURE IS ASSOCIATED WITH A POTENT MID LEVEL SHORTWAVE TROUGH THAT IS ON PACE TO APPROACH OUR AREA LATE TONIGHT. ANOTHER UPPER LEVEL WAVE NOW OVER THE AL/GA BORDER IS EXPECTED TO TRACK ACROSS FAR SRN AND SE NC THIS EVENING. MODELS ARE NOT IN GREAT AGREEMENT ON THE TIMING AND EXTENT OF CONVECTION THIS AFTERNOON/ EVENING. THE 4KM WRF-ARW/WRF-NMM AND HRRR DEPICT JUST SCATTERED COVERAGE IN THE EARLY AFTERNOON IN THE ERN CWA... WHERE THE CINH HAS VANISHED AND WHERE MLCAPE HAS ALREADY CLIMBED NEAR 1000 J/KG. BUT THE DEEP LAYER SHEAR IS QUITE POOR (UNDER 15 KTS) AND EXPECTED TO REMAIN SO THROUGH THE DAY... NOT SUPPORTIVE OF STRONG ORGANIZED CONVECTION. PW WILL ALSO BE DROPPING A BIT THIS AFTERNOON... AND THE STRONG MISS VALLEY WAVE SHIFTING EASTWARD MAY HELP DEAMPLIFY THE AL/GA WAVE AS IT CROSSES THE CAROLINAS. WILL ADJUST POPS A BIT THROUGH THE AFTERNOON TO FOCUS THE BETTER COVERAGE (30-40%) IN THE EAST... WHERE MOISTURE AND INSTABILITY IS EXPECTED TO BE BETTER BENEATH WEAK UPPER-LEVEL DPVA... WITH LOWER POPS OF 20-30% IN THE WRN CWA. LOCALLY HEAVY RAIN IS STILL POSSIBLE WITH WARM LAYERS (LCL-0C) OF 3.5-3.8 KM... AND ANY ADDITIONAL RAIN IN AREAS THAT SAW A LOT YESTERDAY (SUCH AS THE GREENSBORO AREA) COULD EASILY SEE QUICK FLOODING TODAY. FREQUENT LIGHTNING IS STILL A SECONDARY CONCERN... ALTHOUGH THE MARGINAL -10C TO -30C CAPE PEAKING AT 500 J/KG IS NOT AS HIGH AS IN SOME OF THE PROLIFIC LIGHTNING EVENTS WE`VE HAD RECENTLY. TEMP RISE SO FAR HAS BEEN GREATLY TEMPERED BY STUBBORN STRATOCU OVER MUCH OF CENTRAL NC... WITH ONLY ERN/SRN SECTION SEEING SOME HOLES IN THE CLOUDS. EXPECT THIS WILL START TO MIX OUT SHORTLY (BASED ON PILOT REPORTS THAT THIS DECK IS 500-1000 FT THICK)... BUT WITH THE DELAYED INSOLATION... WILL STILL NEED TO TRIM A FEW DEGREES OFF HIGHS... GOING WITH 85-90. -GIH WHILE BULK OF CONVECTION WILL DIMINISH IN THE EVENING WITH LOSS OF HEATING...APPROACH OF THE MID-UPPER LEVEL TROUGH WILL LIKELY MAINTAIN A FEW SHOWERS/STORMS INTO THE OVERNIGHT HOURS. CONTINUED MUGGY TONIGHT WITH MIN TEMPS NEAR 70-LOWER 70S. -WSS && .SHORT TERM /TUESDAY AND TUESDAY NIGHT/... AS OF 300 AM MONDAY... EXPECT A CONTINUATION OF THE UNSETTLED WEATHER PATTERN TUESDAY DUE TO PRESENCE OF MID-UPPER LEVEL TROUGH OVER THE CAROLINAS THOUGH FOCUS MAY BE MORE IN THE EAST VERSUS WEST. SHORT TERM MODEL GUIDANCE SUGGEST WESTERLY 850MB FLOW DEVELOPING LATE TODAY INTO TUESDAY WITH A 850MB TROUGH CROSSING THE REGION TUESDAY AFTERNOON. RH CROSS SECTION SUGGEST THE AIR MASS DRYING OUT ABOVE 700MB/10K FT DURING THE COURSE OF THE AFTERNOON...ESPECIALLY WEST OF HIGHWAY 1. THE DOWNSLOPE FLOW IN THE WAKE OF THIS SYSTEM AND AN AIR MASS NOT AS MOIST MAY LIMIT/INHIBIT CONVECTIVE DEVELOPMENT IN THE WEST ON TUESDAY. WITH TROUGH CROSSING THE EAST DURING MAX HEATING...STILL EXPECT AT A MINIMUM 50 PERCENT COVERAGE. PRESENCE OF DRIER AIR ALOFT MAY LEAD TO EVAPORATIVE COOLING IN VICINITY OF THUNDERSTORM DOWNDRAFTS...LEADING TO STRONG/LOCALLY DAMAGING WINDS WITH THE STRONGER CELLS. MAJORITY OF THE CONVECTION WILL DISSIPATE SHORTLY AFTER SUNSET THOUGH THE APPROACH OF A SECONDARY TROUGH IN THE FLOW ALOFT MAY TRIGGER ADDITIONAL ACTIVITY LATE TUESDAY NIGHT-EARLY WEDNESDAY MORNING. THE DRIER AIR MASS ALOFT SHOULD ALLOW FOR PERIODS OF PARTIAL SUNSHINE. THIS MAY LEAD TO AFTERNOON TEMPS A COUPLE OF DEGREES WARMER THAN TODAY. EXPECT MAX TEMPS NEAR 90 TO LOWER 90S AREAWIDE. MIN TEMPS NEAR 70-LOWER 70S. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... AS OF 300 AM MONDAY... WEDNESDAY THROUGH THURSDAY: THE MEAN TROUGH IN PLACE OVER THE EASTERN US WILL CONTINUE TO UNDERGO GRADUAL AMPLIFICATION WEDNESDAY AND THURSDAY AS A SERIES OF LOW AMPLITUDE SHORT WAVES ROUND THE BASE OF TROUGH AND MOVE ACROSS THE REGION. THE QUASI-STATIONARY SURFACE FRONT ACROSS EASTERN NORTH CAROLINA WILL SAG SLOWLY SOUTH AND EAST OF THE AREA BY WEDNESDAY NIGHT OR THURSDAY AS WEAK SURFACE HIGH PRESSURE OVER THE OHIO VALLEY BUILDS EAST-SOUTHEASTWARD INTO THE NORTHEAST AND MID-ATLANTIC STATES. DPVA ASSOCIATED WITH SHORTWAVE ENERGY MOVING THROUGH THE AREA WITHIN THE CONTINUED MOIST AND UNSTABLE AIRMASS WILL SUPPORT A CONTINUATION OF MOSTLY DIURNAL SHOWERS AND THUNDERSTORM BOTH DAYS. EXPECT THE HIGHEST POPS ACROSS CENTRAL AND EASTERN PORTIONS OF THE PIEDMONT AND COASTAL PLAIN COUNTIES ON WEDNESDAY IN PROXIMITY TO THE SURFACE FRONT AND DEEPER MOISTURE. THERE SHOULD BE CONSIDERABLY LESS COVERAGE ON THURSDAY...ESPECIALLY ACROSS THE WESTERN AND CENTRAL PIEDMONT WITH THE ADVECTION OF DRIER AIR FROM THE NW. A FEW STRONG TO SEVERE STORMS WILL BE POSSIBLE MAINLY ACROSS CENTRAL AND EASTERN NC. NEAR NORMAL TEMPERATURES WITH HIGHS IN THE UPPER 80S NW TO LOWER 90S SE. LOWS IN THE UPPER 60S NW TO LOWER 70S SE. FRIDAY THROUGH SUNDAY: FRIDAY AND POSSIBLY SATURDAY COULD END BEING CONVECTION FREE... WITH THE FRONT STALLED SOUTH OF THE AREA AND VOID OF ANY UPPER LEVEL DISTURBANCES TRACKING INTO THE AREA IN THE WEST-NORTHWESTERLY FLOW ALOFT AS THE BROAD TROUGH WILL BE IN THE PROCESS OF RELOADING. ADDITIONALLY...CENTRAL NC COULD SEE A BRIEF REPRIEVE FROM THE SUMMERTIME HUMIDITY WITH DEWPOINTS FALLING INTO THE MID 60S IN THE LOW-LEVEL NORTH-NORTHEASTERLY FEED AROUND THE SURFACE RIDGE AXIS EXTENDING DOWN THE MID-ATLANTIC SEABOARD. HIGHS 85 TO 90. LOWS 65 TO 70. TIMING REMAINS IN QUESTION WITH THE NEXT SHORTWAVE TROUGH AND ASSOCIATED COLD FRONT INTO THE AREA FROM THE WEST LATE SATURDAY NIGHT THROUGH SUNDAY. FOR NOW WILL CARRY CLIMATOLOGY POPS OF 20 TO 30 PERCENT. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... AS OF 1230 PM MONDAY... MVFR CIGS SEEN THIS MORNING AT ALL CENTRAL NC TAF SITES HAVE FINALLY BEGUN TO BREAK UP... WITH CLOUDS BASED 2-3 KFT NOW VARYING BETWEEN SCT AND BKN. THESE CLOUDS WILL CONTINUE TO SLOWLY LIFT AND MIX OUT... BECOMING PREVAILING VFR AT ALL SITES BY 20Z. OTHERWISE... SCATTERED SHOWERS/STORMS ARE EXPECTED ACROSS CENTRAL NC (FORMING FIRST IN THE WEST NEAR INT/GSO... WITH EVENTUALLY MORE COVERAGE EXPECTED IN THE EAST NEAR RDU/RWI/FAY) BETWEEN 19Z AND 02Z... BUT THE LIMITED COVERAGE AND LOW CONFIDENCE IN TIMING PRECLUDES MENTIONING THUNDER OR SUB-VFR VSBY/CLOUDS AS A PREVAILING CONDITION DURING THIS TIME FRAME. A PERIOD OF VFR CONDITIONS IS EXPECTED 02Z-07Z AT ALL SITES... THEN MVFR TO IFR STRATOCUMULUS IS EXPECTED TO REDEVELOP (ESPECIALLY AT RDU/RWI/FAY) AFTER 07Z TONIGHT. THESE CLOUDS SHOULD SLOWLY LIFT TO VFR BY 16Z TUESDAY. WINDS WILL REMAIN LIGHT THROUGH THIS FORECAST PERIOD... MAINLY FROM THE SW SHIFTING A BIT TO WSW... AT SPEEDS OF 10 KTS OR LESS... 5 KTS OR LESS AT NIGHT. LOOKING BEYOND 18Z TUESDAY... VFR CONDITIONS SHOULD DOMINATE THROUGH WEDNESDAY MORNING WITH GENERALLY DRY WEATHER... ALTHOUGH BRIEF MVFR FOG IS EXPECTED AROUND 08Z-13Z EARLY WEDNESDAY MORNING. SHOWERS/ STORMS WITH A PERIOD OF MVFR CONDITIONS IS POSSIBLE WEDNESDAY AFTERNOON AND EVENING. EARLY MORNING SUB-VFR CONDITIONS ARE ANTICIPATED EACH MORNING THURSDAY THROUGH SATURDAY. -GIH && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...WSS NEAR TERM...HARTFIELD/WSS SHORT TERM...WSS LONG TERM...CBL AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1020 AM EDT MON JUL 22 2013 .SYNOPSIS... AN UPPER LEVEL TROUGH WILL SLOWLY DEEPEN OVER THE EASTERN U.S. THROUGH TUESDAY. AT THE SURFACE...A WEAK BOUNDARY WILL REMAIN OVER CENTRAL NORTH CAROLINA THROUGH WEDNESDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1015 AM MONDAY... REST OF TODAY: VERY MOIST AIR MASS IN PLACE AS NOTED BY 12Z GSO/MHX SOUNDINGS AND BLENDED TPW IMAGERY... WITH PW RANGING FROM 2.0-2.2 INCHES WEST TO EAST... ALTHOUGH VALUES ARE SLIGHTLY LOWER TO OUR WEST. LATEST SURFACE ANALYSIS SHOWS THE NEARLY STATIONARY SYNOPTIC FRONTAL ZONE FROM IA EAST ACROSS NRN IL/IN/OH TO PA/MA. A WEAK LOW IS EVIDENT OVER SCENTRAL VA WITH TRAILING WEAK TROUGHING THROUGH CENTRAL NC... AND A MORE PROMINENT LOW AND TROUGH OVER SRN IL/SE MO/NW AR. THE LATTER FEATURE IS ASSOCIATED WITH A POTENT MID LEVEL SHORTWAVE TROUGH THAT IS ON PACE TO APPROACH OUR AREA LATE TONIGHT. ANOTHER UPPER LEVEL WAVE NOW OVER THE AL/GA BORDER IS EXPECTED TO TRACK ACROSS FAR SRN AND SE NC THIS EVENING. MODELS ARE NOT IN GREAT AGREEMENT ON THE TIMING AND EXTENT OF CONVECTION THIS AFTERNOON/ EVENING. THE 4KM WRF-ARW/WRF-NMM AND HRRR DEPICT JUST SCATTERED COVERAGE IN THE EARLY AFTERNOON IN THE ERN CWA... WHERE THE CINH HAS VANISHED AND WHERE MLCAPE HAS ALREADY CLIMBED NEAR 1000 J/KG. BUT THE DEEP LAYER SHEAR IS QUITE POOR (UNDER 15 KTS) AND EXPECTED TO REMAIN SO THROUGH THE DAY... NOT SUPPORTIVE OF STRONG ORGANIZED CONVECTION. PW WILL ALSO BE DROPPING A BIT THIS AFTERNOON... AND THE STRONG MISS VALLEY WAVE SHIFTING EASTWARD MAY HELP DEAMPLIFY THE AL/GA WAVE AS IT CROSSES THE CAROLINAS. WILL ADJUST POPS A BIT THROUGH THE AFTERNOON TO FOCUS THE BETTER COVERAGE (30-40%) IN THE EAST... WHERE MOISTURE AND INSTABILITY IS EXPECTED TO BE BETTER BENEATH WEAK UPPER-LEVEL DPVA... WITH LOWER POPS OF 20-30% IN THE WRN CWA. LOCALLY HEAVY RAIN IS STILL POSSIBLE WITH WARM LAYERS (LCL-0C) OF 3.5-3.8 KM... AND ANY ADDITIONAL RAIN IN AREAS THAT SAW A LOT YESTERDAY (SUCH AS THE GREENSBORO AREA) COULD EASILY SEE QUICK FLOODING TODAY. FREQUENT LIGHTNING IS STILL A SECONDARY CONCERN... ALTHOUGH THE MARGINAL -10C TO -30C CAPE PEAKING AT 500 J/KG IS NOT AS HIGH AS IN SOME OF THE PROLIFIC LIGHTNING EVENTS WE`VE HAD RECENTLY. TEMP RISE SO FAR HAS BEEN GREATLY TEMPERED BY STUBBORN STRATOCU OVER MUCH OF CENTRAL NC... WITH ONLY ERN/SRN SECTION SEEING SOME HOLES IN THE CLOUDS. EXPECT THIS WILL START TO MIX OUT SHORTLY (BASED ON PILOT REPORTS THAT THIS DECK IS 500-1000 FT THICK)... BUT WITH THE DELAYED INSOLATION... WILL STILL NEED TO TRIM A FEW DEGREES OFF HIGHS... GOING WITH 85-90. -GIH WHILE BULK OF CONVECTION WILL DIMINISH IN THE EVENING WITH LOSS OF HEATING...APPROACH OF THE MID-UPPER LEVEL TROUGH WILL LIKELY MAINTAIN A FEW SHOWERS/STORMS INTO THE OVERNIGHT HOURS. CONTINUED MUGGY TONIGHT WITH MIN TEMPS NEAR 70-LOWER 70S. -WSS && .SHORT TERM /TUESDAY AND TUESDAY NIGHT/... AS OF 300 AM MONDAY... EXPECT A CONTINUATION OF THE UNSETTLED WEATHER PATTERN TUESDAY DUE TO PRESENCE OF MID-UPPER LEVEL TROUGH OVER THE CAROLINAS THOUGH FOCUS MAY BE MORE IN THE EAST VERSUS WEST. SHORT TERM MODEL GUIDANCE SUGGEST WESTERLY 850MB FLOW DEVELOPING LATE TODAY INTO TUESDAY WITH A 850MB TROUGH CROSSING THE REGION TUESDAY AFTERNOON. RH CROSS SECTION SUGGEST THE AIR MASS DRYING OUT ABOVE 700MB/10K FT DURING THE COURSE OF THE AFTERNOON...ESPECIALLY WEST OF HIGHWAY 1. THE DOWNSLOPE FLOW IN THE WAKE OF THIS SYSTEM AND AN AIR MASS NOT AS MOIST MAY LIMIT/INHIBIT CONVECTIVE DEVELOPMENT IN THE WEST ON TUESDAY. WITH TROUGH CROSSING THE EAST DURING MAX HEATING...STILL EXPECT AT A MINIMUM 50 PERCENT COVERAGE. PRESENCE OF DRIER AIR ALOFT MAY LEAD TO EVAPORATIVE COOLING IN VICINITY OF THUNDERSTORM DOWNDRAFTS...LEADING TO STRONG/LOCALLY DAMAGING WINDS WITH THE STRONGER CELLS. MAJORITY OF THE CONVECTION WILL DISSIPATE SHORTLY AFTER SUNSET THOUGH THE APPROACH OF A SECONDARY TROUGH IN THE FLOW ALOFT MAY TRIGGER ADDITIONAL ACTIVITY LATE TUESDAY NIGHT-EARLY WEDNESDAY MORNING. THE DRIER AIR MASS ALOFT SHOULD ALLOW FOR PERIODS OF PARTIAL SUNSHINE. THIS MAY LEAD TO AFTERNOON TEMPS A COUPLE OF DEGREES WARMER THAN TODAY. EXPECT MAX TEMPS NEAR 90 TO LOWER 90S AREAWIDE. MIN TEMPS NEAR 70-LOWER 70S. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... AS OF 300 AM MONDAY... WEDNESDAY THROUGH THURSDAY: THE MEAN TROUGH IN PLACE OVER THE EASTERN US WILL CONTINUE TO UNDERGO GRADUAL AMPLIFICATION WEDNESDAY AND THURSDAY AS A SERIES OF LOW AMPLITUDE SHORT WAVES ROUND THE BASE OF TROUGH AND MOVE ACROSS THE REGION. THE QUASI-STATIONARY SURFACE FRONT ACROSS EASTERN NORTH CAROLINA WILL SAG SLOWLY SOUTH AND EAST OF THE AREA BY WEDNESDAY NIGHT OR THURSDAY AS WEAK SURFACE HIGH PRESSURE OVER THE OHIO VALLEY BUILDS EAST-SOUTHEASTWARD INTO THE NORTHEAST AND MID-ATLANTIC STATES. DPVA ASSOCIATED WITH SHORTWAVE ENERGY MOVING THROUGH THE AREA WITHIN THE CONTINUED MOIST AND UNSTABLE AIRMASS WILL SUPPORT A CONTINUATION OF MOSTLY DIURNAL SHOWERS AND THUNDERSTORM BOTH DAYS. EXPECT THE HIGHEST POPS ACROSS CENTRAL AND EASTERN PORTIONS OF THE PIEDMONT AND COASTAL PLAIN COUNTIES ON WEDNESDAY IN PROXIMITY TO THE SURFACE FRONT AND DEEPER MOISTURE. THERE SHOULD BE CONSIDERABLY LESS COVERAGE ON THURSDAY...ESPECIALLY ACROSS THE WESTERN AND CENTRAL PIEDMONT WITH THE ADVECTION OF DRIER AIR FROM THE NW. A FEW STRONG TO SEVERE STORMS WILL BE POSSIBLE MAINLY ACROSS CENTRAL AND EASTERN NC. NEAR NORMAL TEMPERATURES WITH HIGHS IN THE UPPER 80S NW TO LOWER 90S SE. LOWS IN THE UPPER 60S NW TO LOWER 70S SE. FRIDAY THROUGH SUNDAY: FRIDAY AND POSSIBLY SATURDAY COULD END BEING CONVECTION FREE... WITH THE FRONT STALLED SOUTH OF THE AREA AND VOID OF ANY UPPER LEVEL DISTURBANCES TRACKING INTO THE AREA IN THE WEST-NORTHWESTERLY FLOW ALOFT AS THE BROAD TROUGH WILL BE IN THE PROCESS OF RELOADING. ADDITIONALLY...CENTRAL NC COULD SEE A BRIEF REPRIEVE FROM THE SUMMERTIME HUMIDITY WITH DEWPOINTS FALLING INTO THE MID 60S IN THE LOW-LEVEL NORTH-NORTHEASTERLY FEED AROUND THE SURFACE RIDGE AXIS EXTENDING DOWN THE MID-ATLANTIC SEABOARD. HIGHS 85 TO 90. LOWS 65 TO 70. TIMING REMAINS IN QUESTION WITH THE NEXT SHORTWAVE TROUGH AND ASSOCIATED COLD FRONT INTO THE AREA FROM THE WEST LATE SATURDAY NIGHT THROUGH SUNDAY. FOR NOW WILL CARRY CLIMATOLOGY POPS OF 20 TO 30 PERCENT. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... AS OF 730 AM MONDAY... A MOIST AIR MASS WILL REMAIN OVER CENTRAL NC THROUGH MID WEEK. MEANWHILE AN UPPER LEVEL TROUGH WILL DRIFT SLOWLY EAST FROM THE TN VALLEY TODAY TO THE CAROLINAS TUESDAY. THIS UPPER LEVEL FEATURE WILL REMAIN OVER THE REGION THROUGH THURSDAY THEN WEAKEN/DISSIPATE. DISTURBANCES ROTATING THROUGH THIS TROUGH...INTERACTING WITH THE MOIST AIR MASS AND AFTERNOON HEATING...WILL TRIGGER SCATTERED-NUMEROUS SHOWERS AND THUNDERSTORMS EACH DAY. CONVECTIVE COVERAGE IS EXPECTED TO BE GREATEST IN THE LATE AFTERNOON THROUGH THE EARLY EVENING HOURS THOUGH ISOLATED SHOWERS MAY OCCUR AT ANY TIME. EXPECT MVFR/IFR CEILINGS AND MVFR VISIBILITIES IN VICINITY OF THE SHOWERS AND STORMS. THIS SCENARIO SHOULD PLAY OUT EACH AFTERNOON THROUGH WEDNESDAY WITH LESS COVERAGE EXPECTED THURSDAY AND FRIDAY. DUE TO THE PRESENCE OF THE MOIST AIR...WIDESPREAD STRATUS AND ASSOCIATED IFR CEILINGS WILL OCCUR EACH MORNING JUST PRIOR TO DAYBREAK...CONTINUING UNTIL 11 AM OR NOON EACH DAY. POCKETS OF IFR VISIBILITY DUE TO FOG MAY ALSO OCCUR. THE FOG SHOULD LIFT BY 9-10 AM EACH DAY. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...WSS NEAR TERM...HARTFIELD/WSS SHORT TERM...WSS LONG TERM...CBL AVIATION...WSS
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
148 AM EDT MON JUL 22 2013 .SYNOPSIS... FAIRLY SEASONABLE TEMPERATURES AND A NORMAL SCATTERING OF AFTERNOON STORMS ARE EXPECTED THE NEXT SEVERAL DAYS...COMPLIMENTS OF BERMUDA HIGH PRESSURE. A COLD FRONT DROPPING CLOSE TO THE REGION ON THURSDAY WILL STALL AND KEEP THE WEATHER A BIT MORE UNSETTLED. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... AS OF 2:00 AM MONDAY...NO CHANGES TO THE FORECAST WITH THE LATEST UPDATE. PREVIOUS DISCUSSION FOLLOWS: WATER VAPOR IMAGERY SHOWS AN ANTICYCLONIC (CLOCKWISE) SPIN OVER THE EASTERN CAROLINAS. MODELS ARE STRUGGLING TO CONSISTENTLY LOCATE REGIONS OF CYCLONIC CURVATURE THAT MAY BE HELPING SUSTAIN CLUSTERS OF SHOWERS AND T-STORMS. AGAIN REFERENCING WATER VAPOR IMAGERY IT APPEARS ONE UPPER DISTURBANCE LIES ACROSS CENTRAL NORTH CAROLINA INTO WEST-CENTRAL SOUTH CAROLINA...WHILE A SECOND MORE QUIESCENT DISTURBANCE LIES OFF THE GEORGIA AND SOUTHERN SOUTH CAROLINA COAST. THE AIRMASS REMAINS SEASONABLY WARM...BUT MOISTURE CONTENT AS MEASURED BY PRECIPITABLE WATER IS VERY HIGH: 2.2 INCHES. LAPSE RATES ARE NOT PARTICULARLY STEEP BUT ARE JUST LARGE ENOUGH THROUGH THE 900-600 MB LAYER TO PROMOTE GOOD UPDRAFT ACCELERATION. IR SATELLITE SHOWS CLOUD TOP TEMPERATURES MAINTAINING LARGE AREAS COLDER THAN -60C. BASED ON RECENT TRENDS AND THE LAST SEVERAL HRRR RUNS (WHICH HAVEN`T BEEN BAD THIS EVENING) THE CONVECTION ACROSS THE SC PEE DEE REGION SHOULD LARGELY DISSIPATE WITHIN THE NEXT 2-3 HOURS WHILE NEW CONVECTION DEVELOPS CLOSER TO THE COAST...ESPECIALLY THE NC COAST. AFTER 2 AM MOST OF THE CONVECTION SHOULD EXIT THE LANDMASS AND MOVE EASTWARD INTO THE OCEAN. HIGH-REFLECTIVITY (>50DBZ) CORES HAVE SO FAR REMAINED VERY LOW IN THE STORMS...BARELY ABOVE THE FREEZING LEVEL. THIS IS CORRELATED WITH EFFICIENT HEAVY RAIN PRODUCTION BUT NOT WITH SEVERE WEATHER. SINCE CELL MOVEMENT REMAINS SLOW FROM THE WEST FLOODING WILL BE THE PRIMARY THREAT TO WATCH FOR THE NEXT SEVERAL HOURS. && .SHORT TERM /6 AM THIS MORNING THROUGH TUESDAY NIGHT/... AS OF 3 PM SUNDAY...COPIOUS MOISTURE REMAINS IN PLACE ON MONDAY WITH PRECIPITABLE WATER STILL ABOVE 2 INCHES. WHILE WIDESPREAD CLOUD COVER INHIBITED INSOLATION AND THUS CONVECTIVE COVERAGE TODAY THIS APPEARS A LITTLE LESS LIKELY MONDAY.FCST SOUNDINGS LESS INDICATIVE OF WIDESPREAD SC EARLY IN THE DAY SO EXPECT BETTER HEATING AND THUS COVERAGE OF STORMS. ITS HARD TO PIN DOWN ANY FAVORED AREAS FOR HIGHER POPS...ABUT A LATE DAY UPPER VORT AND SFC TROUGH MAY FOCUS ACTIVITY OVER WESTERN ZONES EVEN AS A LARGER SCALE DIURNAL WANING IS UNDERWAY. A STRONGER VORT WILL SCOOT BY TO OUR NORTH ON TUESDAY...PERHAPS AROUND MIDDAY. IN ITS WAKE WILL BE A SUPPRESSING EFFECT ON CONVECTION AND SOME 20-30 POPS SEEM ALL THAT IS WARRANTED. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... AS OF 3 PM SUNDAY...PATTERN ALOFT REMAINS AMPLIFIED THROUGH THE PERIOD WITH 5H TROUGHING OVER THE EAST COAST AND RIDGING OUT WEST. THIS MAINTAINS ACTIVE WEATHER ACROSS THE SOUTHEAST WITH PIEDMONT TROUGH AND SEA BREEZE BEING THE FOCUS ON WED. FROM THU ON WEAK COLD FRONT MOVES INTO THE REGION BUT STALLS WITH FLOW ALOFT BECOMING PARALLEL TO THE SURFACE BOUNDARY. HAVE A HARD TIME BELIEVING THE FRONT WILL MAKE IT TO THE COAST FOR ANY LENGTH OF TIME WITH THE 5H TROUGH AXIS REMAINING WEST OF THE AREA. WEAK WAVES DEVELOPING ON THE FRONT WILL BRIEFLY PUSH THE BOUNDARY TO THE COAST BEFORE ALLOWING IT TO RETURN INLAND. IN ADDITION TO NUDGING THE FRONT EAST OR WEST THESE WAVES SHOULD HELP GENERATE AND ENHANCE CONVECTION. TIMING THE FEATURES AT THIS POINT IS DIFFICULT AT BEST SO WILL MAINTAIN CHANCE POP THROUGH THE FORECAST PERIOD. FRONT WILL SLOWLY DISSIPATE DURING THE SECOND HALF OF THE PERIOD...EVENTUALLY MERGING WITH THE PIEDMONT TROUGH. NEXT WEEKEND A SHORTWAVE MOVING INTO THE MS VALLY INDUCES A SURFACE LOW WHICH THEN LIFTS NORTHEAST THROUGH THE OH VALLEY. COLD FRONT ASSOCIATED WITH THE LOW MOVES INTO THE CAROLINAS LATE IN THE PERIOD. STRONGER 5H TROUGH SUGGESTS THIS FRONT MAY HAVE A BETTER CHANCE OF REACHING OR MOVING OFF THE COAST. AT THE VERY LEAST IT WILL RESULT IN AN INCREASE IN PRECIP CHANCES FOR THE WEEKEND...ESPECIALLY SUN. DAILY CONVECTION AND CLOUD COVER WILL KEEP HIGHS NEAR TO SLIGHTLY BELOW CLIMO WHILE SOUTHERLY FLOW...MOISTURE AND LEFT OVER DEBRIS CLOUD KEEP LOWS NEAR TO SLIGHTLY ABOVE CLIMO. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... AS OF 06Z...AN AREA OF LIGHT TO MODERATE SHOWERS FROM KFLO TO KLBT WILL GRADUALLY DISSIPATE OVER THE NEXT SEVERAL HOURS. AFTER THE PRECIPITATION ENDS MVFR CONDITIONS WILL GIVE WAY TO IFR CIGS/VSBYS AS FOG DEVELOPS. AT THE COASTAL TERMINALS...SHOWERS WILL OCCUR MAINLY OFFSHORE THUS WILL INDICATE VCSH THROUGH SUNRISE. SCATTERED CLOUDS AT THE IFR LEVEL WITH TEMPO BROKEN MVFR CEILINGS CAN BE EXPECTED. TEMPO IFR CIGS SHOULD OCCUR MAINLY IN THE PRE-DAWN HOURS. ANY IFR CIGS SHOULD RISE TO MVFR BY 14Z WITH VFR DEVELOPING LATE MORNING INTO EARLY AFTERNOON. SHOULD BE A GOOD CHANCE OF VCSH AT THE COASTAL TERMINALS BY NOON LOCAL WITH VCTS DEVELOPING AT KFLO/KLBT WITH THE APPROACH OF AN UPPER IMPULSE. THIS ACTIVITY WILL LIKELY PERSIST INTO THE EVENING HOURS. EXTENDED OUTLOOK...ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED THROUGH THURSDAY...WITH BRIEF LOCALIZED PERIODS OF MVFR/IFR POSSIBLE. OTHERWISE EXPECT VFR. && .MARINE... NEAR TERM/THROUGH TONIGHT/... AS OF 2:00 AM MONDAY...NO CHANGES TO THE FORECAST WITH THE LATEST UPDATE. PREVIOUS DISCUSSION FOLLOWS: WINDS FINALLY SURGED UP IN THE LAST FEW HOURS BUT ARE STILL WELL BELOW ADVISORY THRESHOLDS. RECENT GUSTS INCLUDE 21 KNOTS AT THE FRYING PAN SHOALS BUOY...NORTH MYRTLE BEACH...AND OAK ISLAND...20 KNOTS ON BALD HEAD ISLAND...AND 19 KNOTS IN GEORGETOWN. THESE STRONGER SOUTHWEST WINDS MAY CONTINUE THROUGH 11 PM OR MIDNIGHT BEFORE A LANDBREEZE PRODUCES MUCH LIGHTER WEST-SOUTHWEST WINDS NEAR THE BEACHES...SPREADING OUT AWAY FROM THE COAST OVERNIGHT. SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 3 PM SUNDAY...WEAK WAVE OF LOW PRESSURE NEAR DELMARVA WILL VEER LOCAL FLOW SLIGHTLY TO A MORE WESTERLY DIRECTION THAN THE TYPICAL SW FOR PART OF MONDAY. LATER IN THE DAY SW FLOW GETS ESTABLISHED WITH ABOUT A 5KT INC IN SPEED. THIS TREND WILL CONTINUE INTO MONDAY NIGHT BUT NOT TO WHERE CAUTIONARY HEADLINES WARRANTED AS SEAS NOT EXPECTED TO BUILD QUITE ENOUGH WITHIN 20NM BORDER. PIEDMONT TROUGHINESS DEVELOPS LATER FRIDAY AND SHOULD MAINTAIN SLIGHTLY HIGHER WIND SPEEDS THAN WHAT SEASONABLE...15 TO 20KT MOST ZONES. A LITTLE LIGHTER FLOW OVER SRN LEGS WHICH SHOULD PREVENT 5 FT SEAS OFF GTOWN. LONG TERM /WEDNESDAY THROUGH FRIDAY/... AS OF 3 PM SUNDAY...SOUTHWEST FLOW WILL CONTINUE THROUGH THE PERIOD WITH WATERS IN BETWEEN BERMUDA HIGH AND PIEDMONT TROUGH/WEAK COLD FRONT. WINDS AND SEAS WILL BE HIGHEST EARLY IN THE PERIOD. GRADIENT RELAXES AS FRONT/TROUGH MOVE CLOSER TO THE COAST AND WEAK SURFACE WAVES DEVELOP ON THE BOUNDARY. SPEEDS WILL BE 10 TO 15 KT WED THEN DECREASE TO AROUND 10 KT FOR THU AND FRI. SEAS WILL FALL FROM 3 TO 4 FT ON WED TO AROUND 2 FT FRI. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ AVIATION...MRR
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
928 PM CDT TUE JUL 23 2013 .UPDATE... ISSUED AT 928 PM CDT TUE JUL 23 2013 ONLY MINOR UPDATES AS ONE WEAK SHORTWAVE BRINGS STORMS INTO SD AND THE NEXT SHORTWAVE STILL WELL UPSTREAM OVER CANADA. CONTINUE TO THINK THAT ANY PRECIP WILL BE WELL AFTER MIDNIGHT. LOWERED TEMPS JUST A BIT IN THE FAR EASTERN COUNTIES AS DEW POINTS HAVE BEEN LOWER IN THAT AREA. UPDATE ISSUED AT 627 PM CDT TUE JUL 23 2013 NO MAJOR CHANGES FOR THIS UPDATE AS THE CONVECTION IN CENTRAL ND IS ON TRACK TO MISS OUR SOUTHWESTERN COUNTIES. THE BETTER CHANCES FOR ANY PRECIP WILL BE AFTER MIDNIGHT TONIGHT. TEMPS SHOULD BOTTOM OUT IN THE 50S. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT) ISSUED AT 309 PM CDT TUE JUL 23 2013 MAIN FORECAST CHALLENGE REMAINS PCPN CHANCES OVER THE NEXT FEW DAYS. MODELS SEEM TO BE IN BETTER AGREEMENT ON THE DETAILS THIS TIME AROUND WHICH MATCH UP PRETTY WELL WITH FORECAST CONTINUITY. THEREFORE DO NOT PLAN MANY CHANGES TO THE SHORT TERM. QUITE A BIT OF CUMULUS FORMED ACROSS THE AREA AGAIN TODAY WHICH LIKELY HELPED TO HOLD DOWN TEMPS A LITTLE. EXPECT THE CUMULUS TO THIN OUT THIS EVENING. THE MID AND HIGH LEVEL CLOUDS ASSOCIATED WITH AREA OF PCPN OVER NORTHWEST ND SHOULD DRIFT INTO PORTIONS OF THE FA. ANY ACTUAL PCPN SHOULD TRACK FROM NORTHWEST ND DOWN INTO NORTHEAST SD TONIGHT. LATEST VERSION OF THE RAP SEEMS TO SHOW THIS WELL. WILL LEAVE INHERITED PCPN CHANCES ACROSS THE SOUTHWEST FOR LATE TONIGHT BASICALLY AS IS. PRETTY DRY SFC DEW POINT READINGS ESPECIALLY IN THE EAST SO CUT BACK A LITTLE ON MIN TEMPS THERE. FOR WED THERE ARE NOT A LOT OF CHANGES FROM TODAY. STILL IN NW FLOW WITH WEAK EMBEDDED IMPULSES. MODELS ALL SEEM CONSISTENT IN SHOWING SOME LIGHT PCPN ACROSS THE AREA. THESE CHANCES SHOULD SHIFT INTO NORTHWEST MN WED NIGHT. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 309 PM CDT TUE JUL 23 2013 BY THU THE NEXT SFC COLD FRONT WILL SWING THRU THE FA WITH A LITTLE STRONGER UPPER LEVEL DISTURBANCE. THIS WILL PROBABLY BE THE TIME PERIOD WITH THE BEST CHANCE FOR PCPN ALTHOUGH AMOUNTS WILL BE PRETTY LIGHT. WILL LEAVE THU NIGHT DRY. STILL HAVE SOME QUESTIONS ABOUT PCPN CHANCES AGAIN BY FRI. MODELS ARE INDICATING A SUBSTANTIAL PIECE OF SHORTWAVE ENERGY DROPPING THROUGH WITH CHILLY 500MB TEMPS. LEFT SOME LOW CHANCES FOR PCPN IN THE EAST. FOR FRI NIGHT THROUGH TUE...THE PERIOD WILL BEGIN WITH TEMPS BELOW NORMAL AND DRY WEATHER...WITH COOL CANADIAN HIGH PRESSURE IN CONTROL. TEMPS AND MOISTURE PROFILES WILL INCREASE BY EARLY NEXT WEEK...WITH A CHANCE FOR SHOWERS AND STORMS WITH MORE ZONAL FLOW ALOFT. MOST AREAS COULD REMAIN DRY THROUGH MONDAY...WITH DRY AIR IN PLACE INITIALLY AND IT WILL TAKE TIME TO MOISTEN COLUMN. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING) ISSUED AT 627 PM CDT TUE JUL 23 2013 VFR CONDITIONS WILL CONTINUE THROUGHOUT THE PERIOD. THERE IS A SMALL CHANCE FOR SOME CONVECTION TOMORROW...BUT CONFIDENCE IN IT AFFECTING ANY ONE TAF SITE IS LOW SO WILL LEAVE OUT FOR NOW. LIGHT AND VARIABLE WINDS WILL PICK UP TO AROUND 8 TO 10 KTS BY WEDNESDAY AFTERNOON. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ UPDATE...JR SHORT TERM...GODON LONG TERM...GODON/DK AVIATION...JR
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
627 PM CDT TUE JUL 23 2013 .UPDATE... ISSUED AT 627 PM CDT TUE JUL 23 2013 NO MAJOR CHANGES FOR THIS UPDATE AS THE CONVECTION IN CENTRAL ND IS ON TRACK TO MISS OUR SOUTHWESTERN COUNTIES. THE BETTER CHANCES FOR ANY PRECIP WILL BE AFTER MIDNIGHT TONIGHT. TEMPS SHOULD BOTTOM OUT IN THE 50S. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT) ISSUED AT 309 PM CDT TUE JUL 23 2013 MAIN FORECAST CHALLENGE REMAINS PCPN CHANCES OVER THE NEXT FEW DAYS. MODELS SEEM TO BE IN BETTER AGREEMENT ON THE DETAILS THIS TIME AROUND WHICH MATCH UP PRETTY WELL WITH FORECAST CONTINUITY. THEREFORE DO NOT PLAN MANY CHANGES TO THE SHORT TERM. QUITE A BIT OF CUMULUS FORMED ACROSS THE AREA AGAIN TODAY WHICH LIKELY HELPED TO HOLD DOWN TEMPS A LITTLE. EXPECT THE CUMULUS TO THIN OUT THIS EVENING. THE MID AND HIGH LEVEL CLOUDS ASSOCIATED WITH AREA OF PCPN OVER NORTHWEST ND SHOULD DRIFT INTO PORTIONS OF THE FA. ANY ACTUAL PCPN SHOULD TRACK FROM NORTHWEST ND DOWN INTO NORTHEAST SD TONIGHT. LATEST VERSION OF THE RAP SEEMS TO SHOW THIS WELL. WILL LEAVE INHERITED PCPN CHANCES ACROSS THE SOUTHWEST FOR LATE TONIGHT BASICALLY AS IS. PRETTY DRY SFC DEW POINT READINGS ESPECIALLY IN THE EAST SO CUT BACK A LITTLE ON MIN TEMPS THERE. FOR WED THERE ARE NOT A LOT OF CHANGES FROM TODAY. STILL IN NW FLOW WITH WEAK EMBEDDED IMPULSES. MODELS ALL SEEM CONSISTENT IN SHOWING SOME LIGHT PCPN ACROSS THE AREA. THESE CHANCES SHOULD SHIFT INTO NORTHWEST MN WED NIGHT. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 309 PM CDT TUE JUL 23 2013 BY THU THE NEXT SFC COLD FRONT WILL SWING THRU THE FA WITH A LITTLE STRONGER UPPER LEVEL DISTURBANCE. THIS WILL PROBABLY BE THE TIME PERIOD WITH THE BEST CHANCE FOR PCPN ALTHOUGH AMOUNTS WILL BE PRETTY LIGHT. WILL LEAVE THU NIGHT DRY. STILL HAVE SOME QUESTIONS ABOUT PCPN CHANCES AGAIN BY FRI. MODELS ARE INDICATING A SUBSTANTIAL PIECE OF SHORTWAVE ENERGY DROPPING THROUGH WITH CHILLY 500MB TEMPS. LEFT SOME LOW CHANCES FOR PCPN IN THE EAST. FOR FRI NIGHT THROUGH TUE...THE PERIOD WILL BEGIN WITH TEMPS BELOW NORMAL AND DRY WEATHER...WITH COOL CANADIAN HIGH PRESSURE IN CONTROL. TEMPS AND MOISTURE PROFILES WILL INCREASE BY EARLY NEXT WEEK...WITH A CHANCE FOR SHOWERS AND STORMS WITH MORE ZONAL FLOW ALOFT. MOST AREAS COULD REMAIN DRY THROUGH MONDAY...WITH DRY AIR IN PLACE INITIALLY AND IT WILL TAKE TIME TO MOISTEN COLUMN. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING) ISSUED AT 627 PM CDT TUE JUL 23 2013 VFR CONDITIONS WILL CONTINUE THROUGHOUT THE PERIOD. THERE IS A SMALL CHANCE FOR SOME CONVECTION TOMORROW...BUT CONFIDENCE IN IT AFFECTING ANY ONE TAF SITE IS LOW SO WILL LEAVE OUT FOR NOW. LIGHT AND VARIABLE WINDS WILL PICK UP TO AROUND 8 TO 10 KTS BY WEDNESDAY AFTERNOON. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ UPDATE...JR SHORT TERM...GODON LONG TERM...GODON/DK AVIATION...JR
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1047 AM CDT MON JUL 22 2013 .UPDATE... ISSUED AT 1038 AM CDT MON JUL 22 2013 MAIN CHALLENGES TODAY ARE CLOUDS AND TEMPERATURES. COOL STRATUS CLOUD DECK LIKELY TO BE MORE PERSISTENT TODAY THAN EARLIER FORECAST. AS A RESULT OF MORE CLOUDS ALSO LOWERED TEMPERATURES ABOUT 2 TO 3 DEGREES ACROSS THE NORTH AND CENTRAL. EXPECT SUNNY OR MOSTLY SUNNY SKIES SOUTHWEST. UPDATE ISSUED AT 655 AM CDT MON JUL 22 2013 MAIN PROBLEM FOR THE MORNING UPDATE WAS CLOUD COVER. EXPANSIVE AREA OF STRATUS ACROSS EASTERN SASKATCHEWAN AND MANITOBA IS SPILLING SOUTHWARD INTO NORTH DAKOTA. MOST MODELS ARE NOT CAPTURING THE LOW LEVEL MOISTURE WELL. THE 10 UTC RAP WAS TOO GENEROUS WITH ITS 925MB RH LAYER BUT DOES SEEM TO HAVE A GOOD TREND ON DIMINISHING IT MID MORNING INTO EARLY AFTERNOON. USED A BLEND OF THE RAP WITH CURRENT OBS AND COORDINATION WITH FGF TO TAKE A SHOT AT CLOUD COVER DURING THE DAY. WITH ONLY A THIN LAYER OF MOISTURE...THINK EVEN THE FAR EASTERN PORTIONS OF THE CWA SHOULD SEE SOME AFTERNOON SUNSHINE. OTHERWISE NO SIGNIFICANT CHANGES TO THE CURRENT FORECAST. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 357 AM CDT MON JUL 22 2013 HIGH BASED THUNDERSTORMS LATE THIS EVENING AND TONIGHT ACROSS WESTERN NORTH DAKOTA CAPABLE OF STRONG WINDS WILL HIGHLIGHT THE SHORT TERM FORECAST. OVERALL...A MUCH QUIETER AND COOLER DAY ACROSS WESTERN AND CENTRAL NORTH DAKOTA IS EXPECTED COMPARED TO SUNDAY. GIVEN GOOD MODEL AGREEMENT OF SURFACE HIGH PRESSURE ACROSS MUCH OF NORTH DAKOTA...AND LEE LOW PRESSURE ACROSS NORTHEAST WYOMING THROUGH CENTRAL MONTANA...UTILIZED A BLEND OF THE 00 UTC GUIDANCE SUITE. WITH WEAK NORTHERLY FLOW AND A MUCH COOLER AIRMASS IN PLACE...HIGHS IN THE UPPER 60S ARE FORECAST ACROSS THE TURTLE MOUNTAINS...TO THE 70S FOR MOST OTHER LOCATIONS ACROSS THE AREA...WITH MID 80S FOR THE FAR SOUTHWEST WHERE LOW LEVEL THERMAL FIELDS AND MIXING ARE EXPECTED TO BE GREATEST. GIVEN THE GOOD PERFORMANCE OF THE 00 UTC 4KM WRF...AND THE REMAINING HIGH RESOLUTION MODELS CONTAINED WITHIN THE 00 UTC SPC STORM SCALE ENSEMBLE OF OPPORTUNITY...WILL FOLLOW CLOSELY TO THESE SOLUTIONS FOR THE CONVECTIVE POTENTIAL THIS EVENING AND TONIGHT ACROSS THE WEST. EXPECT SURFACE BASE CONVECTIVE DEVELOPMENT ALONG THE AFOREMENTIONED LEE TROUGH ACROSS MONTANA THIS AFTERNOON WITH THE APPROACH OF THE SHORTWAVE CURRENTLY ACROSS WASHINGTON STATE. STORMS ARE FORECAST TO PROPAGATE SOUTHEAST INTO WESTERN NORTH DAKOTA BETWEEN 00-03 UTC. THE 00 UTC NAM/GFS BUFR SOUNDINGS DEPICT INVERTED V PROFILES ACROSS THE WEST THIS EVENING. WHILE OVERALL INSTABILITY IS MARGINAL FOR SEVERE CONVECTION...AMPLE DEEP LAYER SHEAR NEAR 40 KTS AND HIGH BASES NEAR 750-700 MB SUGGEST A LOW END THREAT FOR STRONG WINDS. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 357 AM CDT MON JUL 22 2013 AN ACTIVE PATTERN WILL CONTINUE THROUGH THE EXTENDED PERIOD. WE BEGIN WITH A NORTHWEST FLOW ALOFT AND TRANSITION TO A SOUTHWEST UPPER FLOW LATE IN THE EXTENDED PERIOD. GENERAL AGREEMENT BETWEEN DETERMINISTIC MODELS IN LARGE SCALE FLOW AND WILL UTILIZE A MODEL BLEND WITH PERSISTENCE. ON TUESDAY...HIGH PRESSURE OVER THE EASTERN DAKOTAS WITH UPPER LEVEL JET ENERGY INDUCING SCATTERED SHOWERS AND THUNDERSTORMS OVER WESTERN NORTH DAKOTA EARLY TUESDAY. THIS SHOULD TRANSLATE INTO SOUTH DAKOTA DURING THE MORNING. MODELS INDICATE ANOTHER IMPULSE MOVING THROUGH SOUTHERN CANADA INDUCING SURFACE LOW PRESSURE OVER EASTERN MONTANA BY TUESDAY AFTERNOON. INCREASING WARM ADVECTION AHEAD OF THE LOW COMBINED WITH THE AFOREMENTIONED IMPULSE WILL PRODUCE STEEPENING LAPSE RATES AND A VEERING WIND PROFILE SUPPORTIVE OF STRONG TO SEVERE STORMS TRANSLATING NORTHWEST TO SOUTHEAST ACROSS THE LOCAL AREA TUESDAY AFTERNOON THROUGH TUESDAY NIGHT. PERHAPS SOME LINGERING CONVECTION IN THE FAR EAST WEDNESDAY BUT FOR THE MOST PART WEDNESDAY IS EXPECTED TO BE DRY AS SURFACE HIGH PRESSURE TRACKS ACROSS THE AREA. THURSDAY IS ALSO EXPECTED TO BE RELATIVELY QUIET BUT UPPER LEVEL JET ENERGY REMAINING OVER THE AREA COMBINED WITH DIURNAL HEATING WILL STILL SUPPORT ISOLATED TO SCATTERED THUNDERSTORMS. A MORE SIGNIFICANT WAVE MOVES THROUGH THE AREA THURSDAY NIGHT INTO FRIDAY BRINGING ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS. UPPER LEVEL RIDGING BUILDS OVER THE AREA ON SATURDAY. THE ECMWF IS QUICKER TO BRING THE RIDGE INTO THE AREA RESULTING IN A DRY FORECAST SATURDAY. THE GFS KEEPS AN AREA OF CONVECTION OVER THE WEST AND SOUTH CENTRAL THROUGH MIDDAY BEFORE DRYING THINGS OUT LATER IN THE DAY. THE ECMWF IS ALSO QUICKER TO BREAK DOWN THE RIDGE AND INTRODUCE SOUTHWEST FLOW OVER THE AREA BY SUNDAY AFTERNOON...WHILE THE GFS KEEPS THE LOCAL AREA DRY ON SUNDAY WITH ANY CONVECTION HOLDING OFF UNTIL LATE SUNDAY NIGHT IN THE FAR WEST. ALL IN ALL A RATHER ACTIVE PATTERN WITH SEASONABLE TEMPERATURES. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1038 AM CDT MON JUL 22 2013 AT 10 AM CDT...SURFACE HIGH PRESSURE OVER SASKATCHEWAN AND MANITOBA WAS BUILDING SOUTH INTO THE NORTHERN PLAINS. COOL STRATO-CU LAYER HAS EXTENDED ACROSS ALL BUT THE SOUTHWEST. AM NOW MORE PESSIMISTIC ON THE EVENTUAL BREAKUP OF THE CLOUD DECK BY LATE THIS MORNING. EXTENDED THE CLOUDS THROUGH THE EARLY TO MID AFTERNOON. MVFR CONDITIONS FROM KMOT-KBIS-KJMS THROUGH 20Z...THEN IMPROVING TO VFR. KDIK SHOULD REMAIN VFR...WHILE KISN WILL BE IN THE EDGE...BECOMING VFR A LITTLE EARLIER. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...WAA SHORT TERM...AYD LONG TERM...TWH AVIATION...WAA
AREA FORECAST DISCUSSION
NWS BISMARCK ND
656 AM CDT MON JUL 22 2013 .UPDATE... ISSUED AT 655 AM CDT MON JUL 22 2013 MAIN PROBLEM FOR THE MORNING UPDATE WAS CLOUD COVER. EXPANSIVE AREA OF STRATUS ACROSS EASTERN SASKATCHEWAN AND MANITOBA IS SPILLING SOUTHWARD INTO NORTH DAKOTA. MOST MODELS ARE NOT CAPTURING THE LOW LEVEL MOISTURE WELL. THE 10 UTC RAP WAS TOO GENEROUS WITH ITS 925MB RH LAYER BUT DOES SEEM TO HAVE A GOOD TREND ON DIMINISHING IT MID MORNING INTO EARLY AFTERNOON. USED A BLEND OF THE RAP WITH CURRENT OBS AND COORDINATION WITH FGF TO TAKE A SHOT AT CLOUD COVER DURING THE DAY. WITH ONLY A THIN LAYER OF MOISTURE...THINK EVEN THE FAR EASTERN PORTIONS OF THE CWA SHOULD SEE SOME AFTERNOON SUNSHINE. OTHERWISE NO SIGNIFICANT CHANGES TO THE CURRENT FORECAST. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 357 AM CDT MON JUL 22 2013 HIGH BASED THUNDERSTORMS LATE THIS EVENING AND TONIGHT ACROSS WESTERN NORTH DAKOTA CAPABLE OF STRONG WINDS WILL HIGHLIGHT THE SHORT TERM FORECAST. OVERALL...A MUCH QUIETER AND COOLER DAY ACROSS WESTERN AND CENTRAL NORTH DAKOTA IS EXPECTED COMPARED TO SUNDAY. GIVEN GOOD MODEL AGREEMENT OF SURFACE HIGH PRESSURE ACROSS MUCH OF NORTH DAKOTA...AND LEE LOW PRESSURE ACROSS NORTHEAST WYOMING THROUGH CENTRAL MONTANA...UTILIZED A BLEND OF THE 00 UTC GUIDANCE SUITE. WITH WEAK NORTHERLY FLOW AND A MUCH COOLER AIRMASS IN PLACE...HIGHS IN THE UPPER 60S ARE FORECAST ACROSS THE TURTLE MOUNTAINS...TO THE 70S FOR MOST OTHER LOCATIONS ACROSS THE AREA...WITH MID 80S FOR THE FAR SOUTHWEST WHERE LOW LEVEL THERMAL FIELDS AND MIXING ARE EXPECTED TO BE GREATEST. GIVEN THE GOOD PERFORMANCE OF THE 00 UTC 4KM WRF...AND THE REMAINING HIGH RESOLUTION MODELS CONTAINED WITHIN THE 00 UTC SPC STORM SCALE ENSEMBLE OF OPPORTUNITY...WILL FOLLOW CLOSELY TO THESE SOLUTIONS FOR THE CONVECTIVE POTENTIAL THIS EVENING AND TONIGHT ACROSS THE WEST. EXPECT SURFACE BASE CONVECTIVE DEVELOPMENT ALONG THE AFOREMENTIONED LEE TROUGH ACROSS MONTANA THIS AFTERNOON WITH THE APPROACH OF THE SHORTWAVE CURRENTLY ACROSS WASHINGTON STATE. STORMS ARE FORECAST TO PROPAGATE SOUTHEAST INTO WESTERN NORTH DAKOTA BETWEEN 00-03 UTC. THE 00 UTC NAM/GFS BUFR SOUNDINGS DEPICT INVERTED V PROFILES ACROSS THE WEST THIS EVENING. WHILE OVERALL INSTABILITY IS MARGINAL FOR SEVERE CONVECTION...AMPLE DEEP LAYER SHEAR NEAR 40 KTS AND HIGH BASES NEAR 750-700 MB SUGGEST A LOW END THREAT FOR STRONG WINDS. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 357 AM CDT MON JUL 22 2013 AN ACTIVE PATTERN WILL CONTINUE THROUGH THE EXTENDED PERIOD. WE BEGIN WITH A NORTHWEST FLOW ALOFT AND TRANSITION TO A SOUTHWEST UPPER FLOW LATE IN THE EXTENDED PERIOD. GENERAL AGREEMENT BETWEEN DETERMINISTIC MODELS IN LARGE SCALE FLOW AND WILL UTILIZE A MODEL BLEND WITH PERSISTENCE. ON TUESDAY...HIGH PRESSURE OVER THE EASTERN DAKOTAS WITH UPPER LEVEL JET ENERGY INDUCING SCATTERED SHOWERS AND THUNDERSTORMS OVER WESTERN NORTH DAKOTA EARLY TUESDAY. THIS SHOULD TRANSLATE INTO SOUTH DAKOTA DURING THE MORNING. MODELS INDICATE ANOTHER IMPULSE MOVING THROUGH SOUTHERN CANADA INDUCING SURFACE LOW PRESSURE OVER EASTERN MONTANA BY TUESDAY AFTERNOON. INCREASING WARM ADVECTION AHEAD OF THE LOW COMBINED WITH THE AFOREMENTIONED IMPULSE WILL PRODUCE STEEPENING LAPSE RATES AND A VEERING WIND PROFILE SUPPORTIVE OF STRONG TO SEVERE STORMS TRANSLATING NORTHWEST TO SOUTHEAST ACROSS THE LOCAL AREA TUESDAY AFTERNOON THROUGH TUESDAY NIGHT. PERHAPS SOME LINGERING CONVECTION IN THE FAR EAST WEDNESDAY BUT FOR THE MOST PART WEDNESDAY IS EXPECTED TO BE DRY AS SURFACE HIGH PRESSURE TRACKS ACROSS THE AREA. THURSDAY IS ALSO EXPECTED TO BE RELATIVELY QUIET BUT UPPER LEVEL JET ENERGY REMAINING OVER THE AREA COMBINED WITH DIURNAL HEATING WILL STILL SUPPORT ISOLATED TO SCATTERED THUNDERSTORMS. A MORE SIGNIFICANT WAVE MOVES THROUGH THE AREA THURSDAY NIGHT INTO FRIDAY BRINGING ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS. UPPER LEVEL RIDGING BUILDS OVER THE AREA ON SATURDAY. THE ECMWF IS QUICKER TO BRING THE RIDGE INTO THE AREA RESULTING IN A DRY FORECAST SATURDAY. THE GFS KEEPS AN AREA OF CONVECTION OVER THE WEST AND SOUTH CENTRAL THROUGH MIDDAY BEFORE DRYING THINGS OUT LATER IN THE DAY. THE ECMWF IS ALSO QUICKER TO BREAK DOWN THE RIDGE AND INTRODUCE SOUTHWEST FLOW OVER THE AREA BY SUNDAY AFTERNOON...WHILE THE GFS KEEPS THE LOCAL AREA DRY ON SUNDAY WITH ANY CONVECTION HOLDING OFF UNTIL LATE SUNDAY NIGHT IN THE FAR WEST. ALL IN ALL A RATHER ACTIVE PATTERN WITH SEASONABLE TEMPERATURES. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 655 AM CDT MON JUL 22 2013 MVFR STRATUS CONTINUES TO SPREAD ACROSS NORTHWEST AND CENTRAL NORTH DAKOTA AND WILL IMPACT KMOT AND KISN THROUGH AT LEAST 15 UTC...BEFORE BEGINNING TO LIFT AND SCATTER. THE STRATUS WILL LIKELY IMPACT KBIS AND KJMS DURING THIS TIMEFRAME AS WELL...HOWEVER...UNCERTAINTY IS HIGHER HERE AS THE STRATUS FIELD SHOULD NOT BE AS WIDESPREAD NEAR THESE TERMINALS. THERE IS A CHANCE OF THUNDERSTORMS ACROSS WESTERN NORTH DAKOTA TONIGHT...HOWEVER...DUE TO UNCERTAINTY IN COVERAGE...WILL LEAVE THE MENTION OUT OF THE KISN AND KDIK TAFS. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...TWH SHORT TERM...AYD LONG TERM...TWH AVIATION...AYD
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1152 PM CDT SUN JUL 21 2013 .UPDATE... ISSUED AT 1147 PM CDT SUN JUL 21 2013 LONE SEVERE STORM CONTINUES TO PROPAGATE SE INTO CENTRAL PORTION OF THE FORECAST AREA WITH VERY LITTLE HAPPENING ELSEWHERE. CONTINUED TO ADJUST POPS BASED ON CURRENT AND EXPECTED PCPN TRACK. NO OTHER CHANGES MADE. UPDATE ISSUED AT 945 PM CDT SUN JUL 21 2013 DEEP CONVECTION WEAKENED EARLY THIS EVENING AS IT MOVED INTO THE FAR WESTERN FORECAST AREA. T IS NOW VERY ISOLATED WITH STRONGEST CELL JUST NORTH OF LAKOTA. LOW LEVEL JET FORECAST TO INCREASE WITH BEST CONVERGENCE ALONG INTERNATIONAL BORDER AREA OF MN OVERNIGHT. HAVE MAINTAIN HIGHEST POPS THIS AREA THROUGH MOST OF THE NIGHT. ELSEWHERE STORM POTENTIAL MORE IN QUESTION AND HAVE OVERALL DECREASED POPS SIGNIFICANTLY ACROSS SOUTH HALF OF FA WITH LACK OF CONVERGENCE AND FAVORED MID LEVEL SUPPORT IN CANADA. ANY OTHER CHANGES TO FORECAST MINOR. UPDATE ISSUED AT 633 PM CDT SUN JUL 21 2013 LINE OF DEEP CONVECTION EXTENDING FROM NEAR PILOT MOUND MB TO RUGBY AND WEST OF BIS. BASED ON CURRENT TIMING ADJUSTED POPS DELAYING HIGHER POPS ACROSS NW AND KEEPING SOUTHERN FA DRY LONGER. NO OTHER CHANGES THIS UPDATE. && .SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT) ISSUED AT 303 PM CDT SUN JUL 21 2013 MAIN CHALLENGE CONTINUES TO BE TSTM CHANCES AND SEVERITY FOR TONIGHT. LATEST MODEL GUIDANCE CONTINUES TO SUPPORT A THREAT FOR PORTIONS OF THE FA BUT EARLY ON MAINLY FOR THE KDVL REGION AS IT SHOULD TAKE A WHILE TO REACH THE RED RIVER VALLEY. CURRENTLY HAVE A COLD FRONT WORKING INTO FAR NORTHWEST ND WITH AN AREA OF LOW PRESSURE THERE AS WELL. A WARM FRONT EXTENDS SE FROM THIS LOW DOWN TO NEAR KBIS AND KABR. IN THIS WARM SECTOR DEW POINTS ARE GENERALLY IN THE LOW TO MID 60S WITH TEMPS IN THE 80S. EAST OF THE WARM FRONT DEW POINTS HAVE BEEN SLOW TO RECOVER FROM MORNING LOWS WITH 50S STILL COMMON. THERE HAS BEEN A WEAK TSTM COMPLEX OVER SOUTHWEST MANITOBA RIDING AHEAD OF THE MAIN SHORT WAVE. THIS SHOULD GET INTO THE FAR NW FA IN THE NEXT HOUR OR SO. INSTABILITY IS WEAK OUT AHEAD OF THIS INITIAL COMPLEX BUT IT MAY CONTINUE TO MOVE EAST ALONG THE BORDER WITH THE UPPER JET DYNAMICS IN PLACE. THE SEVERE THREAT SHOULD BE BEHIND THIS COMPLEX CLOSER TO THE COLD FRONT AND SFC LOW OVER WESTERN ND. INSTABILITY IS BETTER HERE WITH THE ABOVE MENTIONED WARMER AND MOIST AIR. THE MAIN SHORT WAVE ENERGY APPEARS TO BE LOCATED OVER SOUTHERN ALBERTA WHICH IS NEARING THE SFC BOUNDARY. WITH THE WAVE AND THE UPPER JET ENERGY A MORE ORGANIZED TSTM COMPLEX IS EXPECTED TO GET UNDERWAY OUT WEST. SPC HAS ISSUED MCD 1456 AND A NEW TORNADO WATCH FOR PORTIONS OF WESTERN AND CENTRAL ND. THERE HAVE BEEN A COUPLE OF CELLS THAT HAVE POPPED UP NEAR KISN THAT MAY BE THE START OF SOME STRONGER CELLS. NOT EXPECTING ANY STRONG STORMS TO APPROACH OUR WESTERN FA FOR A FEW MORE HOURS YET SO WE WILL HAVE TIME TO WATCH AND SEE HOW THINGS DEVELOP. LATEST RAP BRINGS SOME STORMS INTO OUR WESTERN FA IN THE 01-02Z MON TIME FRAME. NSSL WRF IS A LITTLE FASTER AND AS MENTIONED IN AN EARLIER AFD UPDATE IT DID BRING TSTMS A LOT FURTHER SOUTH THAN WHAT IS ANTICIPATED. FOLLOWED MORE CONTINUITY AND KEPT HIGHER PCPN CHANCES ACROSS THE NORTHERN HALF OF THE FA TONIGHT WITH LOWER CHANCES ACROSS THE SOUTH. THE COMBINATION OF THE LOW LEVEL JET UPPER JET AND THE WAVE SHOULD KEEP SHOWERS AND TSTMS GOING AFTER DARK JUST NOT SURE HOW LONG THE SEVERE POTENTIAL WILL GO. LEFT SOME LINGERING LOW PCPN CHANCES ACROSS THE EAST ON MONDAY MORNING WITH DRYING ACROSS THE WEST. SHOULD BE A FAIRLY NICE DAY WITH DRIER AIR MOVING BACK IN WITH NORTHWEST WINDS. MON NIGHT WILL BE A LITTLE COOL AGAIN ESPECIALLY ACROSS THE NORTH. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 303 PM CDT SUN JUL 21 2013 SHOULD REMAIN DRY TUE WITH FAIRLY LIGHT WINDS DUE TO THE PROXIMITY OF THE SFC HIGH. CHANCES FOR PCPN RETURN BY TUE NIGHT AND WED ALTHOUGH MODELS NOT IN VERY GOOD AGREEMENT ON THE DETAILS. WEDNESDAY NIGHT-SUNDAY...12Z MODELS MAINTAIN SIMILAR IDEA AS PREVIOUS RUNS. NORTHWEST FLOW ALOFT INTO FRIDAY WITH UPPER RIDGING BUILDING INTO THE REGION FOR THE WEEKEND. THERE WILL BE SLIGHT THUNDERSTORM CHANCES WITH ANY UPPER WAVE WITHIN THE NORTHWEST FLOW ALOFT...WITH THESE CHANCES ENDING ONCE THE RIDGING BUILDS INTO THE REGION. TEMPERATURES NEAR OR SLIGHTLY BELOW NORMAL VALUES. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1147 PM CDT SUN JUL 21 2013 CONFINED T MENTION TO BJI AND TVF FOR THE NEXT COUPLE HOURS. LONE STRONG/SEVERE STORM WILL CONTINUE TO PROPAGATE SE INTO CENTRAL PORTION OF FORECAST AREA. MVFR CIGS/VSBY IN STRONGER STORM OTHERWISE VFR. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ UPDATE...VOELKER SHORT TERM...GODON LONG TERM...GODON/TG AVIATION...VOELKER
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
601 PM EDT MON JUL 22 2013 .SYNOPSIS... MID/UPPER DISTURBANCES MOVING UP THE OHIO VALLEY INTO WEDNESDAY WITH ROUNDS OF CONVECTION. FLASH FLOOD HAZARD LINGERS. && .NEAR TERM /THROUGH TUESDAY/... 6PM UPDATE...TWEAKED POP GRIDS THIS EVENING BASED ON CURRENT RADAR TRENDS. OTHERWISE...MADE NO MAJOR CHANGES TO THE FORECAST. PREVIOUS DISCUSSION FOLLOWS... WILL BE TRACKING A POTENT UPR LVL SYS...LOCATED ACROSS W OH AND KY...WITH A MESO VORTEX APPENDAGE MOVING NE INTO NE KY. USED LATEST RUC AND HRRR FOR TIMING AND PLACEMENT OF POPS WITH THIS SYS WITH HVY SHRA CURRENTLY MOVING BACK INTO NE KY AND SE OH AND INTO S WV/SW VA BY 21Z. HAVE SCT SHRA IN GRIDS IN MEANTIME. LOW CLDS SCT OUT ACROSS WV/SW VA RVR WHICH WILL HELP TO DESTABILIZE ATMOS FOR THIS SYS TO WORK ON THIS AFTN. ROLLED WITH CATEGORICAL POPS MOST PLACES LATE AFTN INTO EARLY THIS EVE AND INSERTED HVY RA WORDING IN COVERAGE TERMS AS PWATS ON EITHER SIDE OF 2 INCHES. FLASH FLOOD WATCH CONT THRU TONIGHT. UPR TROF CROSSES TONIGHT WITH PERHAPS ADDITIONAL SHRA/TSRA MOVING IN THIS EVE AFFECTING SE OH/NE KY/N WV. TROF AXIS SHOULD BE E OF AREA AFTER 09Z WITH PCPN THREAT DIMINISHING. THINK SOME LOW STRATUS AND FG DEVELOPS OVERNIGHT WHICH MAY TAKE UNTIL MID MORNING TO SCT OUT. HAVE ISO TO SCT SHRA/TSRA BY AFTN...WITH AN UPTICK LATE WITH A FAST MOVING SYS DROPPING IN NW FLOW ALOFT. ROLLED WITH WARMER GUIDANCE TONIGHT AND TOMORROW...THINKING AREA SHOULD GET A DECENT SHOT OF SUN TOMORROW BEFORE SHRA/TSRA GET GOING. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/... COLD FRONT SWINGS THROUGH TUESDAY NIGHT AS 5H TROF SWINGS THROUGH AT THE MID LEVELS. CARRIED LIKELY POPS AS THERE WILL BE DECENT DYNAMIC FORCING COUPLED WITH PLENTY OF A AVAILABLE MOISTURE. HOWEVER...CHANCES FOR SEVERE WEATHER ASSOCIATED WITH THIS FEATURE WILL BE LIMITED DUE TO THE LACK OF DAYTIME HEATING DURING THE OVERNIGHT HOURS. AS HIGH PRESSURE BUILDS IN WEDNESDAY...BULK OF MOISTURE WILL BE SHUNTED TO THE EAST...LEADING TO A DRYING TREND. SHOULD SEE A NOTICEABLE DECREASE IN CONVECTIVE ACTIVITY WEDNESDAY AND THURSDAY AS LOW AND MID LEVEL COOL POOL HELPS TO STABILIZE THE ATMOSPHERE. LEFT CHANCE POPS IN FOR MOUNTAINS AS HEATING IN ELEVATED TERRAIN COULD STILL LEAD TO SOME CONVECTIVE DEVELOPMENT. WILL SEE A COOLING TREND THIS PERIOD. GOING WITH MODEL BLEND FOR TEMPERATURES THIS PERIOD. && .LONG TERM /FRIDAY THROUGH MONDAY/... DRIER AIR MOVES IN TO CLOSE OUT THE WEEK AS TROUGH DIGS OVER THE GREAT LAKES SATURDAY AND SUNDAY. GFS AND EURO MODELS HANDLING FEATURES IN SEPARATE FASHION AND DEFERRED TO HPC GRIDS FOR EXTENDED PERIOD. NO MAJOR CHANGES TO WPC MEDIUM RANGE GUIDANCE TEMPERATURES. && .AVIATION /22Z MONDAY THROUGH SATURDAY/... UPR LVL SYS MOVES THRU THIS AFTN AND EVE WITH SHRA/TSRA INCREASING IN COVERAGE. HAVE SOME TEMPO IFR IN TAF SITES WITH OTHERWISE LOW END VFR/HIGH MVFR CIGS IN CU FIELD. UPR TROF MOVES ACROSS TONIGHT WITH PERHAPS ANOTHER ROUND OF SHRA. EXPECT LOW STRATUS TO DEVELOP OVERNIGHT...WITH MAINLY IFR CIGS SAVE FOR SOME LIFR CIGS FOR KPKB AND KEKN. FG TRICKY DESPITE CONFIDENCE TAF SITES RECEIVES SOME RA. MAY BE LOOKING AT A COMBO OF LOW STRATUS AND FG. HAVE SOME IFR VSBY IN FOR NOW. LOW STRATUS AND FG WILL LIFT AND SCT BY 14Z...INTO LOW END VFR CU FOR AFTN. MAINLY ISO SHRA DEVELOPING BY END OF TAF PERIOD. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z WEDNESDAY... FORECAST CONFIDENCE: MEDIUM. ALTERNATE SCENARIOS: TIMING MVFR OR WORSE CONDITIONS MAY VARY THIS AFTERNOON AND EVENING. TIMING/DENSITY OF FOG AND STRATUS MAY VARY OVERNIGHT. TIMING OF RAINFALL AND ASSOCIATED MVFR OR WORSE CONDITIONS MAY VARY THIS AFTERNOON AND EVENING. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. UTC 1HRLY 20 21 22 23 00 01 02 03 04 05 06 07 EDT 1HRLY 16 17 18 19 20 21 22 23 00 01 02 03 CRW CONSISTENCY H H H H H H M M M M L L HTS CONSISTENCY H H H H M L M M M M L L BKW CONSISTENCY H H H H H H H H M M M H EKN CONSISTENCY H H H H M M H H H H L M PKB CONSISTENCY M M L L M M M H H L M M CKB CONSISTENCY M M M M H H M H M M L M AFTER 00Z WEDNESDAY... IFR OR WORSE FOG POSSIBLE WEDNESDAY MORNING. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR WVZ005>011-013>020- 024>040-046-047. OH...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR OHZ066-067-075-076- 083>087. KY...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR KYZ101>103-105. VA...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR VAZ003-004. && $$ SYNOPSIS...KMC/30 NEAR TERM...SL/30 SHORT TERM...KMC LONG TERM...KMC AVIATION...30
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
339 PM EDT MON JUL 22 2013 .SYNOPSIS... MID/UPPER DISTURBANCES MOVING UP THE OHIO VALLEY INTO WEDNESDAY WITH ROUNDS OF CONVECTION. FLASH FLOOD HAZARD LINGERS. && .NEAR TERM /THROUGH TUESDAY/... WILL BE TRACKING A POTENT UPR LVL SYS...LOCATED ACROSS W OH AND KY...WITH A MESO VORTEX APPENDAGE MOVING NE INTO NE KY. USED LATEST RUC AND HRRR FOR TIMING AND PLACEMENT OF POPS WITH THIS SYS WITH HVY SHRA CURRENTLY MOVING BACK INTO NE KY AND SE OH AND INTO S WV/SW VA BY 21Z. HAVE SCT SHRA IN GRIDS IN MEANTIME. LOW CLDS SCT OUT ACROSS WV/SW VA RVR WHICH WILL HELP TO DESTABILIZE ATMOS FOR THIS SYS TO WORK ON THIS AFTN. ROLLED WITH CATEGORICAL POPS MOST PLACES LATE AFTN INTO EARLY THIS EVE AND INSERTED HVY RA WORDING IN COVERAGE TERMS AS PWATS ON EITHER SIDE OF 2 INCHES. FLASH FLOOD WATCH CONT THRU TONIGHT. UPR TROF CROSSES TONIGHT WITH PERHAPS ADDITIONAL SHRA/TSRA MOVING IN THIS EVE AFFECTING SE OH/NE KY/N WV. TROF AXIS SHOULD BE E OF AREA AFTER 09Z WITH PCPN THREAT DIMINISHING. THINK SOME LOW STRATUS AND FG DEVELOPS OVERNIGHT WHICH MAY TAKE UNTIL MID MORNING TO SCT OUT. HAVE ISO TO SCT SHRA/TSRA BY AFTN...WITH AN UPTICK LATE WITH A FAST MOVING SYS DROPPING IN NW FLOW ALOFT. ROLLED WITH WARMER GUIDANCE TONIGHT AND TOMORROW...THINKING AREA SHOULD GET A DECENT SHOT OF SUN TOMORROW BEFORE SHRA/TSRA GET GOING. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/... COLD FRONT SWINGS THROUGH TUESDAY NIGHT AS 5H TROF SWINGS THROUGH AT THE MID LEVELS. CARRIED LIKELY POPS AS THERE WILL BE DECENT DYNAMIC FORCING COUPLED WITH PLENTY OF A AVAILABLE MOISTURE. HOWEVER...CHANCES FOR SEVERE WEATHER ASSOCIATED WITH THIS FEATURE WILL BE LIMITED DUE TO THE LACK OF DAYTIME HEATING DURING THE OVERNIGHT HOURS. AS HIGH PRESSURE BUILDS IN WEDNESDAY...BULK OF MOISTURE WILL BE SHUNTED TO THE EAST...LEADING TO A DRYING TREND. SHOULD SEE A NOTICEABLE DECREASE IN CONVECTIVE ACTIVITY WEDNESDAY AND THURSDAY AS LOW AND MID LEVEL COOL POOL HELPS TO STABILIZE THE ATMOSPHERE. LEFT CHANCE POPS IN FOR MOUNTAINS AS HEATING IN ELEVATED TERRAIN COULD STILL LEAD TO SOME CONVECTIVE DEVELOPMENT. WILL SEE A COOLING TREND THIS PERIOD. GOING WITH MODEL BLEND FOR TEMPERATURES THIS PERIOD. && .LONG TERM /FRIDAY THROUGH MONDAY/... DRIER AIR MOVES IN TO CLOSE OUT THE WEEK AS TROUGH DIGS OVER THE GREAT LAKES SATURDAY AND SUNDAY. GFS AND EURO MODELS HANDLING FEATURES IN SEPARATE FASHION AND DEFERRED TO HPC GRIDS FOR EXTENDED PERIOD. NO MAJOR CHANGES TO WPC MEDIUM RANGE GUIDANCE TEMPERATURES. && .AVIATION /19Z MONDAY THROUGH SATURDAY/... UPR LVL SYS MOVES THRU THIS AFTN AND EVE WITH SHRA/TSRA INCREASING IN COVERAGE. HAVE SOME TEMPO IFR IN TAF SITES WITH OTHERWISE LOW END VFR/HIGH MVFR CIGS IN CU FIELD. UPR TROF MOVES ACROSS TONIGHT WITH PERHAPS ANOTHER ROUND OF SHRA. EXPECT LOW STRATUS TO DEVELOP OVERNIGHT...WITH MAINLY IFR CIGS SAVE FOR SOME LIFR CIGS FOR KPKB AND KEKN. FG TRICKY DESPITE CONFIDENCE TAF SITES RECEIVES SOME RA. MAY BE LOOKING AT A COMBO OF LOW STRATUS AND FG. HAVE SOME IFR VSBY IN FOR NOW. LOW STRATUS AND FG WILL LIFT AND SCT BY 14Z...INTO LOW END VFR CU FOR AFTN. MAINLY ISO SHRA DEVELOPING BY END OF TAF PERIOD. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z TUESDAY... FORECAST CONFIDENCE: MEDIUM. ALTERNATE SCENARIOS: TIMING MVFR OR WORSE CONDITIONS MAY VARY THIS AFTERNOON AND EVENING. TIMING/DENSITY OF FOG AND STRATUS MAY VARY OVERNIGHT. TIMING OF RAINFALL AND ASSOCIATED MVFR OR WORSE CONDITIONS MAY VARY THIS AFTERNOON AND EVENING. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. UTC 1HRLY 20 21 22 23 00 01 02 03 04 05 06 07 EDT 1HRLY 16 17 18 19 20 21 22 23 00 01 02 03 CRW CONSISTENCY H H H H H H M M M M L L HTS CONSISTENCY H H H H M L M M M M L L BKW CONSISTENCY H H H H H H H H M M M H EKN CONSISTENCY H H H H M M H H H H L M PKB CONSISTENCY M M L L M M M H H L M M CKB CONSISTENCY M M M M H H M H M M L M AFTER 18Z TUESDAY... IFR OR WORSE FOG POSSIBLE WEDNESDAY MORNING. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR WVZ005>011-013>020- 024>040-046-047. OH...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR OHZ066-067-075-076- 083>087. KY...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR KYZ101>103-105. VA...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR VAZ003-004. && $$ SYNOPSIS...KMC/30 NEAR TERM...30 SHORT TERM...KMC LONG TERM...KMC AVIATION...30
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
233 PM EDT MON JUL 22 2013 .SYNOPSIS... MID/UPPER DISTURBANCES MOVING UP THE OHIO VALLEY INTO WEDNESDAY WITH ROUNDS OF CONVECTION. FLASH FLOOD HAZARD LINGERS. && .NEAR TERM /THROUGH TUESDAY/... WILL BE TRACKING A POTENT UPR LVL SYS...LOCATED ACROSS W OH AND KY...WITH A MESO VORTEX APPENDAGE MOVING NE INTO NE KY. USED LATEST RUC AND HRRR FOR TIMING AND PLACEMENT OF POPS WITH THIS SYS WITH HVY SHRA CURRENTLY MOVING BACK INTO NE KY AND SE OH AND INTO S WV/SW VA BY 21Z. HAVE SCT SHRA IN GRIDS IN MEANTIME. LOW CLDS SCT OUT ACROSS WV/SW VA RVR WHICH WILL HELP TO DESTABILIZE ATMOS FOR THIS SYS TO WORK ON THIS AFTN. ROLLED WITH CATEGORICAL POPS MOST PLACES LATE AFTN INTO EARLY THIS EVE AND INSERTED HVY RA WORDING IN COVERAGE TERMS AS PWATS ON EITHER SIDE OF 2 INCHES. FLASH FLOOD WATCH CONT THRU TONIGHT. UPR TROF CROSSES TONIGHT WITH PERHAPS ADDITIONAL SHRA/TSRA MOVING IN THIS EVE AFFECTING SE OH/NE KY/N WV. TROF AXIS SHOULD BE E OF AREA AFTER 09Z WITH PCPN THREAT DIMINISHING. THINK SOME LOW STRATUS AND FG DEVELOPS OVERNIGHT WHICH MAY TAKE UNTIL MID MORNING TO SCT OUT. HAVE ISO TO SCT SHRA/TSRA BY AFTN...WITH AN UPTICK LATE WITH A FAST MOVING SYS DROPPING IN NW FLOW ALOFT. ROLLED WITH WARMER GUIDANCE TONIGHT AND TOMORROW...THINKING AREA SHOULD GET A DECENT SHOT OF SUN TOMORROW BEFORE SHRA/TSRA GET GOING. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/... EXCEPT FOR THE NAM/SREF SUITE OF MODELS WHICH ARE SLOW OUTLIERS THERE IS GROWING AGREEMENT AMONG THE MODELS OF A FASTER PROGRESSION OF THE COLD FRONT TUESDAY NIGHT...AND OF A QUITE WEAK SECONDARY FRONT WEDNESDAY. FIRST...EXPECT A RAPID DECREASE IN CONVECTION TUESDAY AS AN UPPER DISTURBANCE EXITS AND TAKES MUCH OF THE RICH MOISTURE WITH IT. AGAIN...THE NAM IS A VERY SLOW OUTLIER EXITING THIS SYSTEM AND WAS NOT USED. WILL PAINT HIGH POPS EARLY IN MOUNTAINS BUT DECREASE THAT DURING TUESDAY MORNING. WILL KEEP LOWER POPS TUESDAY AFTERNOON WITH REMAINING LOW LEVEL MOISTURE AND HEATING TO DESTABILIZE THE ATMOSPHERE WELL AHEAD OF THE AFOREMENTIONED COLD FRONT...ESPECIALLY MOUNTAINS WITH AN ELEVATED HEAT SOURCE. WILL RAMP POPS UP AGAIN TUESDAY NIGHT WITH THE FRONT...GOING LIKELY FOR AN ORGANIZED BAND OF CONVECTION ALONG THE FRONT. HOWEVER...LESS RISK OF WATER PROBLEMS WITH THIS FEATURE AS PW`S WILL BE MUCH LESS THAN WE ARE CURRENTLY EXPERIENCING. WILL KEEP LOW POPS IN FOR MAINLY WEDNESDAY AFTERNOON AS THE SECONDARY FRONT DROPS SOUTHEASTWARD ACROSS THE AREA...MOSTLY IN MOUNTAINS. HIGH PRESSURE FINALLY BUILDS IN FOR THURSDAY WITH DRIER AND COOLER AIR BECOMING ESTABLISHED. STILL LINGER JUST A LOW CHANCE POP MOSTLY MOUNTAINS FOR AN AFTERNOON SHOWER PER SQUEEZING OUT ANY LINGERING LOW LEVEL MOISTURE WITH UPSLOPE FLOW AND MODEST COLD ADVECTION ALOFT. LOOK FOR A MODEST COOLING TREND THIS PERIOD...BUT A SIGNIFICANT DRYING OUT. GOING WITH MODEL BLEND FOR TEMPERATURES THIS PERIOD. && .LONG TERM /FRIDAY THROUGH MONDAY/... STILL TRYING TO BRING DRIER AIR THURSDAY INTO FRIDAY. DEEPENING 500 MB TROF OVER EASTERN CANADA MAY PULL ANOTHER DISTURBANCES SE ON SATURDAY. NO MAJOR CHANGES TO WPC MEDIUM RANGE GUIDANCE TEMPERATURES. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... UPR LVL SYS MOVES THRU THIS AFTN AND EVE WITH SHRA/TSRA INCREASING IN COVERAGE. HAVE SOME TEMPO IFR IN TAF SITES WITH OTHERWISE LOW END VFR/HIGH MVFR CIGS IN CU FIELD. UPR TROF MOVES ACROSS TONIGHT WITH PERHAPS ANOTHER ROUND OF SHRA. EXPECT LOW STRATUS TO DEVELOP OVERNIGHT...WITH MAINLY IFR CIGS SAVE FOR SOME LIFR CIGS FOR KPKB AND KEKN. FG TRICKY DESPITE CONFIDENCE TAF SITES RECEIVES SOME RA. MAY BE LOOKING AT A COMBO OF LOW STRATUS AND FG. HAVE SOME IFR VSBY IN FOR NOW. LOW STRATUS AND FG WILL LIFT AND SCT BY 14Z...INTO LOW END VFR CU FOR AFTN. MAINLY ISO SHRA DEVELOPING BY END OF TAF PERIOD. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z TUESDAY... FORECAST CONFIDENCE: MEDIUM. ALTERNATE SCENARIOS: TIMING MVFR OR WORSE CONDITIONS MAY VARY THIS AFTERNOON AND EVENING. TIMING/DENSITY OF FOG AND STRATUS MAY VARY OVERNIGHT. TIMING OF RAINFALL AND ASSOCIATED MVFR OR WORSE CONDITIONS MAY VARY THIS AFTERNOON AND EVENING. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. UTC 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05 EDT 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01 CRW CONSISTENCY H H H H H H H H M M M M HTS CONSISTENCY H H H H H H M L M M M H BKW CONSISTENCY H H H H H H H H H H M M EKN CONSISTENCY H H H H H H M M H H H H PKB CONSISTENCY H H M M L L H H H H H L CKB CONSISTENCY H M M M M M H H M H H H AFTER 18Z TUESDAY... IFR OR WORSE FOG POSSIBLE WEDNESDAY MORNING. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR WVZ005>011-013>020- 024>040-046-047. OH...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR OHZ066-067-075-076- 083>087. KY...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR KYZ101>103-105. VA...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR VAZ003-004. && $$ SYNOPSIS...KMC/30 NEAR TERM...30 SHORT TERM...JMV LONG TERM...KTB AVIATION...30
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
1118 AM EDT MON JUL 22 2013 .SYNOPSIS... SFC FRONT STALLING JUST WEST TO EAST ACROSS WEST VIRGINIA NORTHERN PANHANDLE. MID/UPPER DISTURBANCES MOVING UP THE OHIO VALLEY INTO WEDNESDAY WITH ROUNDS OF CONVECTION. FLASH FLOOD HAZARD LINGERS. && .NEAR TERM /THROUGH TONIGHT/... 1100 AM UPDATE... COMPLICATED FCST SHAPING UP FOR THIS AFTN THRU TONIGHT. WILL BE TRACKING A COUPLE POTENT UPR LVL SYS...THE FIRST OF WHICH CURRENTLY MOVING THRU E OH AND SHOULD BE OUT OF SE OH BY 16Z. THE SECOND LOCATED ACROSS IN AND KY...WITH A MESO VORTEX APPENDAGE MOVING ACROSS S KY. USED LATEST RUC AND HRRR FOR TIMING AND PLACEMENT OF POPS WITH THIS SECOND SYS WITH HVY SHRA MOVING BACK INTO NE KY AND SE OH NEXT FEW HRS AND INTO S WV/SW VA BY 21Z. HAVE SCT SHRA IN GRIDS IN MEANTIME. LOW CLDS TRYING TO SCT OUT E OH OH RVR WHICH WILL HELP TO DESTABILIZE ATMOS FOR THIS SYS TO WORK ON THIS AFTN. ROLLED WITH CATEGORICAL POPS MOST PLACES TDY INTO EARLY THIS EVE AND INSERTED HVY RA WORDING IN COVERAGE TERMS AS PWATS ON EITHER SIDE OF 2 INCHES. FLASH FLOOD WATCH CONT THRU TONIGHT. UPR TROF CROSSES TONIGHT WITH PERHAPS ADDITIONAL SHRA/TSRA MOVING IN THIS EVE AFFECTING SE OH/NE KY/N WV. TROF AXIS SHOULD BE E OF AREA AFTER 09Z WITH PCPN THREAT DIMINISHING. PREVIOUS DISCUSSION BELOW... WATER VAPOR IMAGES INDICATE UPPER LOW SPINNING ACROSS SOUTHERN IL...MOVING EAST INTO THE KY AND THE OH VALLEY TODAY. ALTHOUGH THE SFC FRONT IS SUGGESTED TO REMAIN STATIONARY NORTH OF THE AREA...A POSITIVELY TILTED SHORTWAVES AT H5 WILL APPROACH FROM THE WEST AND NORTHWEST TO INTERACT WITH ABUNDANT LOW LEVEL MOISTURE THIS AFTERNOON TO PRODUCE SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS INTO THE EVENING HOURS. IN FACT...THE NAM SHOWS A H500 SHORTWAVE WITH VORTICITY MAX DOWNSTREAM EAST OF THE TROUGH JUST EAST OF SOUTHEAST OH BY 12Z TODAY. ANOTHER EMBEDDED BUT WEAKER VORT MAX IS EVIDENT UPSTREAM THE TROUGH...WHICH WILL MAKE IT DIG SOUTH INTO WV AND THE APPALACHIANS TONIGHT. THE NAM MODEL SHOW A BUBBLE OF PWATS EXCEEDING 2 INCHES MOVING INTO SOUTHEAST OH BY 15Z TODAY...AND SPREADING NORTHEAST ACROSS SOUTHEAST OH AND PERIOD OF WV THROUGH 00Z TUESDAY. THE NAM...CMC...AND HRRR SUGGEST THAT OUR NORTHWEST QUADRANT WILL RECEIVE THE BEST FORCING DURING THE LATE AFTERNOON...AND ANOTHER PIECE OF ENERGY PASSING ACROSS THE SOUTHERN COALFIELDS AND CENTRAL MOUNTAINS THROUGH TONIGHT. THESE FEATURES COULD ENHANCED CONVECTION DEVELOPMENT OVER THE HIGHER ELEVATIONS...AND ACROSS SOUTHEAST OH AND NORTHERN PORTIONS OF WEST VIRGINIA. THEREFORE...ADJUSTED POPS...HAVING SLIGHT CHANCE POPS IN THE MORNING...AS THE BULK OF PCPN WILL FALL OVER CENTRAL OH. THEN...GRADUALLY INCREASE POPS TO LIKELY THIS AFTERNOON AND CATEGORICAL BY LATE AFTERNOON AND EVENING. USED A BLEND BETWEEN THE BIAS CORRECTED SREF AND GMOS RAW FOR TEMPERATURES THROUGH THE PERIOD. && .SHORT TERM /TUESDAY THROUGH THURSDAY NIGHT/... EXCEPT FOR THE NAM/SREF SUITE OF MODELS WHICH ARE SLOW OUTLIERS THERE IS GROWING AGREEMENT AMONG THE MODELS OF A FASTER PROGRESSION OF THE COLD FRONT TUESDAY NIGHT...AND OF A QUITE WEAK SECONDARY FRONT WEDNESDAY. FIRST...EXPECT A RAPID DECREASE IN CONVECTION TUESDAY AS AN UPPER DISTURBANCE EXITS AND TAKES MUCH OF THE RICH MOISTURE WITH IT. AGAIN...THE NAM IS A VERY SLOW OUTLIER EXITING THIS SYSTEM AND WAS NOT USED. WILL PAINT HIGH POPS EARLY IN MOUNTAINS BUT DECREASE THAT DURING TUESDAY MORNING. WILL KEEP LOWER POPS TUESDAY AFTERNOON WITH REMAINING LOW LEVEL MOISTURE AND HEATING TO DESTABILIZE THE ATMOSPHERE WELL AHEAD OF THE AFOREMENTIONED COLD FRONT...ESPECIALLY MOUNTAINS WITH AN ELEVATED HEAT SOURCE. WILL RAMP POPS UP AGAIN TUESDAY NIGHT WITH THE FRONT...GOING LIKELY FOR AN ORGANIZED BAND OF CONVECTION ALONG THE FRONT. HOWEVER...LESS RISK OF WATER PROBLEMS WITH THIS FEATURE AS PW`S WILL BE MUCH LESS THAN WE ARE CURRENTLY EXPERIENCING. WILL KEEP LOW POPS IN FOR MAINLY WEDNESDAY AFTERNOON AS THE SECONDARY FRONT DROPS SOUTHEASTWARD ACROSS THE AREA...MOSTLY IN MOUNTAINS. HIGH PRESSURE FINALLY BUILDS IN FOR THURSDAY WITH DRIER AND COOLER AIR BECOMING ESTABLISHED. STILL LINGER JUST A LOW CHANCE POP MOSTLY MOUNTAINS FOR AN AFTERNOON SHOWER PER SQUEEZING OUT ANY LINGERING LOW LEVEL MOISTURE WITH UPSLOPE FLOW AND MODEST COLD ADVECTION ALOFT. LOOK FOR A MODEST COOLING TREND THIS PERIOD...BUT A SIGNIFICANT DRYING OUT. GOING WITH MODEL BLEND FOR TEMPERATURES THIS PERIOD. && .LONG TERM /FRIDAY THROUGH SUNDAY/... STILL TRYING TO BRING DRIER AIR THURSDAY INTO FRIDAY. DEEPENING 500 MB TROF OVER EASTERN CANADA MAY PULL ANOTHER DISTURBANCES SE ON SATURDAY. NO MAJOR CHANGES TO WPC MEDIUM RANGE GUIDANCE TEMPERATURES. && .AVIATION /15Z MONDAY THROUGH FRIDAY/... IFR/LIFR UNDER DENSE FOG POSSIBLE OVER AREAS THAT RECEIVED RAIN YESTERDAYS AND WHERE SKY CLEARS. EXPECT THIS CONDITIONS MAINLY AT CRW...CKB...NEARBY BKW AND PKB. PLENTY OF CLOUDINESS IS EVIDENT IN IR SATELLITE IMAGES ASSOCIATED WITH CONVECTION OVER NORTH CENTRAL KY...INTO SOUTHERN OH. H7 FLOW SEEMS TO TAKE THESE CLOUDS NORTH NORTHEAST. SOME CLOUDS WILL FILTER INTO SOUTHEAST OH OVERNIGHT WHILE OTHER PATCHES OF CLOUDS DISSIPATE ALLOWING RADIATIONAL COOLING FOR FOG FORMATION. BY 13Z MONDAY...ANY IFR FOG IS EXPECTED TO LIFT INTO MVFR/VFR CONDITIONS THROUGH GREAT PART OF THE MORNING. MODELS INSIST ON ROUNDS OF SHOWERS OR STORMS DEVELOPING EARLY MORNING ACROSS SOUTHEAST OH...TO MOVE NORTHEAST POSSIBLY AFFECTING PKB THROUGH 15Z. THEN...THE NAM/GFS MODELS BRING A STRONG SHORTWAVE BY 18Z MONDAY JUST WEST OF SOUTHEAST OH. THIS FEATURE WILL ENHANCE CONVECTION MONDAY AFTERNOON FOR IFR CONDITIONS ALONG THE STRONGER SHOWERS. SHOWERS AND THUNDERSTORMS ARE LIKELY TO OVERSPREAD THE SOUTHERN TAF SITES BY MONDAY AFTERNOON AND EVENING. THIS WILL BRING WIDESPREAD MVFR CONDITIONS MON WITH IFR CONDITIONS IN THE HEAVIER RAINFALL. SFC FLOW WILL REMAIN CALM OR LIGHT AND VARIABLE. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z TUESDAY... FORECAST CONFIDENCE: HIGH. ALTERNATE SCENARIOS: TIMING/DENSITY OF FOG MAY VARY OVERNIGHT DEPENDING ON CLOUD COVER. TIMING OF RAINFALL AND ASSOCIATED MVFR OR WORSE CONDITIONS MAY VARY EARLY MORNING TO LATE AFTERNOON MONDAY. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. UTC 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01 EDT 1HRLY 10 11 12 13 14 15 16 17 18 19 20 21 CRW CONSISTENCY H H H L L L L L L M M M HTS CONSISTENCY M M M L M L L L M M M M BKW CONSISTENCY H H H H M L L L L M M M EKN CONSISTENCY H M H H H H M M M M M M PKB CONSISTENCY M H H H H M M M M M M M CKB CONSISTENCY H H H H H H H M M M M M AFTER 12Z TUESDAY... WIDESPREAD IFR TO LIFR POST-RAIN FOG AND/OR LOW CEILINGS OVERNIGHT MON NT INTO TUE MORNING. IFR ALSO POSSIBLE IN VALLEY FOG OR LOW CEILINGS EACH MORNING WED THROUGH THROUGH FRI. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR WVZ005>011-013>020- 024>040-046-047. OH...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR OHZ066-067-075-076- 083>087. KY...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR KYZ101>103-105. VA...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR VAZ003-004. && $$ SYNOPSIS...ARJ/JMV/MZ NEAR TERM...ARJ/30 SHORT TERM...JMV LONG TERM...KTB AVIATION...ARJ
AREA FORECAST DISCUSSION...UPDATED
NWS MORRISTOWN TN
935 PM EDT TUE JUL 23 2013 .DISCUSSION... A COLD FRONT NEAR THE OHIO RIVER WILL SLOWLY MAKES ITS WAY SOUTH TONIGHT...AND CROSS OUR AREA TOMORROW. THERE IS QUITE A BIT OF CONVECTION STILL ONGOING NEAR THE FRONT...AND EXPECT THAT THIS WILL CONTINUE OVERNIGHT AS IT APPROACHES. THE 00Z OHX SOUNDING SHOWS SOME INSTABILITY...WITH A LAYER OF STEEPER LAPSE RATES BETWEEN 800-650 MB. THE RUC SHOWS SOME DIVERGENCE ALOFT TOWARD MORNING AS WELL. MOISTURE IS SOMEWHAT LIMITED SO EXPECT SCATTERED COVERAGE. BEST CHANCES WILL BE NORTH AND WEST. WILL ADJUST THE POP/WX GRIDS SLIGHTLY TO BETTER MATCH THESE TRENDS. TEMPS WILL NEED SOME SLIGHT ADJUSTMENTS AS WELL...MOSTLY UPWARD IN NORTHERN SECTIONS WHERE CLOUD COVER IS EXPECTED TO KEEP LOW TEMPS UP A BIT MORE THAN CURRENTLY FORECAST. && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ DGS
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1242 PM CDT MON JUL 22 2013 .UPDATE... 18Z TAF DISCUSSION. && .AVIATION... MORNING MCS HAS GENERALLY FALLEN APART BUT SOME -SHRA WILL AFFECT CSV THROUGH THE AFTERNOON. SOME REDEVELOPMENT OF -SHRA IS POSSIBLE INTO THE EVENING AT CSV. CIGS RANGE FROM IFR AT CKV TO VFR AT CSV CURRENTLY...BUT GENERAL IMPROVEMENT TO MVFR THIS AFTERNOON AND VFR BY EVENING IS EXPECTED. THE WIDESPREAD RAINFALL SHOULD RESULT IN SOME FOG FORMATION AROUND SUNRISE TUESDAY MORNING WITH MVFR/IFR VIS. LIGHT SOUTHWEST TO WEST WINDS ARE ANTICIPATED THROUGHOUT THE TAF PERIOD. SHAMBURGER && .PREV DISCUSSION... /ISSUED 1022 AM CDT MON JUL 22 2013/ DISCUSSION... HAVE UPDATED ZONES AND GRIDS TO REDUCE POPS OVER THE NORTHWEST. RAIN IS BEGINNING TO TAPER OFF OVER THE NORTHWEST AND EXPECT THIS TREND WILL CONTINUE. BOYD PREV DISCUSSION... /ISSUED 922 AM CDT MON JUL 22 2013/ MESOSCALE UPDATE... ON-GOING GOOD RAIN EVENT ACROSS MIDDLE TENNESSEE. HEAVEIST RAINS HAVE BEEN FALLING OVER SOUTHWEST MIDDLE TENNESSEE WHERE GUIDANCE NUMBERS ARE QUITE A BIT HIGHER. THIS EVENT TIED TO UPPER LEVEL SHORT WAVE CURRENTLY OVER SOUTHERN ILLINOIS DOWN THROUGH EASTERN ARKANSAS. COLDER AIR IS GETTING INJECTED THROUGH THE MID AND UPPER LEVELS. AM EXPECTING BULK OF THE RAIN TO END WEST OF NASHVILLE BY NOON WITH ACTIVITY OVER EASTERN AREAS SCATTERING OUT DURING THE AFTERNOON. CLOUDS AND RAIN WILL HOLD TEMPS DOWN THIS MORNING BUT SHOULD HAVE ENOUGH TIME TO RECOVER THIS AFTERNOON. BOYD PREV DISCUSSION... /ISSUED 520 AM CDT MON JUL 22 2013/ UPDATE...ADDED AVIATION SECTION FOR 12Z TAF`S. AVIATION...BNA/CKV/CSV...UPPER TROUGH IS EXPECTED TO SWING THROUGH MIDDLE TENNESSEE TODAY, BRINGING WIDESPREAD CONVECTION TO THE MID STATE. WILL INCLUDE TEMPO GROUPS TO REFLECT BEST WINDOW OF OPPORTUNITY AT EACH SITE, AS THE WRF MODEL AND HRRR OUTPUT BOTH SHOW SOME ORGANIZATION WITH THE CONVECTION. FREQUENT LIGHTNING IS EXPECTED WITH THE STRONGEST OF THESE STORMS. OVERNIGHT, EXPECT FOG TO DEVELOP DUE TO PARTIAL RADIATIONAL COOLING. PREV DISCUSSION... /ISSUED 324 AM CDT MON JUL 22 2013/ DISCUSSION... THIS VERY WET PATTERN WE HAVE FALLEN VICTIM TO CONTINUES TODAY. IN RESPONSE TO A SHORTWAVE TROUGH THAT IS POSITIVELY TILTED FROM THE WESTERN GREAT LAKES SWWD INTO MISSOURI...A LARGE CLUSTER OF DISORGANIZED SHOWERS AND THUNDERSTORMS ARE PUSHING THROUGH THE MID-MISSISSIPPI VALLEY. WITH NO REASON TO EXPECT THEM TO BEGIN FALLING APART...WILL CONTINUE THIS TREND INTO MIDDLE TENNESSEE FOR THE MORNING HOURS AND SHOW THE WHOLE AREA WITH A DEFINITE POP. WITH VERY LITTLE SHEAR ACCOMPANYING OR AHEAD OF THESE STORMS...WILL REFRAIN FROM ANY SEVERE WORDING TODAY. WHAT WE WILL HAVE TO ACCOUNT FOR THOUGH IS RAIN RATES. MODERATE TO HEAVY RAINFALL WILL ACCOMPANY THESE STORMS AS THEY MOVE THROUGH THE STATE TODAY. WHILE THERE ARE NO WIDESPREAD FLOODING OR FLASH FLOODING CONCERNS...00Z SOUNDINGS AND LATEST PW SATELLITE PRODUCTS DEPICT 1.9 TO 2.1 INCHES OF PW WILL BE IN PLACE TODAY. WITH STORM FLOW EXPECTED TO BE AT LEAST 15-20KTS...IT WILL BE THE TRAINING OF CELLS WE WILL HAVE TO MONITOR...AS 1.5 TO 2 INCHES OF RAINFALL COULD OCCUR IN A SHORT PERIOD OF TIME. THE REST OF THE FORECAST REMAINS GREATLY UNCHANGED WITH THIS PACKAGE. MULTIPLE SHORTWAVES TRAVERSING MOIST AND WARM BOUNDARY LAYER CONDITIONS WILL BRING SCATTERED SHOWERS AND THUNDERSTORMS THROUGH WEDNESDAY. WHILE I STILL DON`T SEE ANYTHING FROM ONE DAY TO THE NEXT TO WARRANT INCLUSION OF SEVERE WORDING IN THE HAZARDOUS WEATHER OUTLOOK...I COULD SEE A MARGINALLY SEVERE STORM OR TWO BEING POSSIBLE EACH OF THE NEXT 3 AFTERNOONS. TEMPERATURES WILL RUN A DEGREE OR TWO WITHIN NORMALS IN THIS PERIOD. WONDERFULLY DRY AIR WILL PUSH INTO THE STATE FOR THURSDAY AND FRIDAY. DEW POINTS IN THE LOW 60S AND NORTHERLY FLOW WILL HELP MAINTAIN NO CHANCE FOR RAIN THESE TWO DAYS. WHILE THE EURO TOOK A HIATUS ON THE YESTERDAY`S 12Z RUN...BOTH OF OUR LONG RANGE MODELS ARE BACK TO SHOWING A FAIRLY INTENSE AND UNSEASONABLE SHORTWAVE TROUGH MOVING INTO THE MID-MISSISSIPPI VALLEY SATURDAY. THE LOCATION AND EVENTUAL PATH OF THIS SYSTEM IS STILL GREATLY IN QUESTION...SO WILL HOLD ONTO CURRENT FORECAST IN REGARDS TO RAIN ON SATURDAY...BUT IF THIS PERSISTS IT MAY WARRANT AN INCREASED CHANCE OF PRECIPITATION IN FUTURE FORECASTS. UNGER AVIATION...06Z TAF DISCUSSION. UPPER TROUGH AXIS WILL APPROACH THE MIDDLE TN AREA FROM THE WEST OVERNIGHT AND ON MONDAY. AS DEEPER MOISTURE SPREAD ACROSS THE AREA TOWARD 12Z...WIDESPREAD SHOWER AND EMBEDDED THUNDERSTORM ACTIVITY IS EXPECTED TO RETURN FROM WEST TO EAST AFT 09Z. THIS ACTIVITY SHOULD EXIT THE CSV AREA AROUND 14Z- 16Z WITH A BREAK FROM THE CONVECTION UNTIL 18-20Z OR SO. PROB30`S WILL THEN BE INCLUDED FOR TSTMS DEVELOPMENT IN THE LATE AFTERNOON. PARTIAL CLEARING EXPECTED AFT 00Z EXCEPT FOR THE CSV AREA WHERE THE LOW CLOUDINESS SHOULD HANG ON. && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1022 AM CDT MON JUL 22 2013 .DISCUSSION... HAVE UPDATED ZONES AND GRIDS TO REDUCE POPS OVER THE NORTHWEST. RAIN IS BEGINNING TO TAPER OFF OVER THE NORTHWEST AND EXPECT THIS TREND WILL CONTINUE. BOYD && .PREV DISCUSSION... /ISSUED 922 AM CDT MON JUL 22 2013/ MESOSCALE UPDATE... ON-GOING GOOD RAIN EVENT ACROSS MIDDLE TENNESSEE. HEAVEIST RAINS HAVE BEEN FALLING OVER SOUTHWEST MIDDLE TENNESSEE WHERE GUIDANCE NUMBERS ARE QUITE A BIT HIGHER. THIS EVENT TIED TO UPPER LEVEL SHORT WAVE CURRENTLY OVER SOUTHERN ILLINOIS DOWN THROUGH EASTERN ARKANSAS. COLDER AIR IS GETTING INJECTED THROUGH THE MID AND UPPER LEVELS. AM EXPECTING BULK OF THE RAIN TO END WEST OF NASHVILLE BY NOON WITH ACTIVITY OVER EASTERN AREAS SCATTERING OUT DURING THE AFTERNOON. CLOUDS AND RAIN WILL HOLD TEMPS DOWN THIS MORNING BUT SHOULD HAVE ENOUGH TIME TO RECOVER THIS AFTERNOON. BOYD PREV DISCUSSION... /ISSUED 520 AM CDT MON JUL 22 2013/ UPDATE...ADDED AVIATION SECTION FOR 12Z TAF`S. AVIATION...BNA/CKV/CSV...UPPER TROUGH IS EXPECTED TO SWING THROUGH MIDDLE TENNESSEE TODAY, BRINGING WIDESPREAD CONVECTION TO THE MID STATE. WILL INCLUDE TEMPO GROUPS TO REFLECT BEST WINDOW OF OPPORTUNITY AT EACH SITE, AS THE WRF MODEL AND HRRR OUTPUT BOTH SHOW SOME ORGANIZATION WITH THE CONVECTION. FREQUENT LIGHTNING IS EXPECTED WITH THE STRONGEST OF THESE STORMS. OVERNIGHT, EXPECT FOG TO DEVELOP DUE TO PARTIAL RADIATIONAL COOLING. PREV DISCUSSION... /ISSUED 324 AM CDT MON JUL 22 2013/ DISCUSSION... THIS VERY WET PATTERN WE HAVE FALLEN VICTIM TO CONTINUES TODAY. IN RESPONSE TO A SHORTWAVE TROUGH THAT IS POSITIVELY TILTED FROM THE WESTERN GREAT LAKES SWWD INTO MISSOURI...A LARGE CLUSTER OF DISORGANIZED SHOWERS AND THUNDERSTORMS ARE PUSHING THROUGH THE MID-MISSISSIPPI VALLEY. WITH NO REASON TO EXPECT THEM TO BEGIN FALLING APART...WILL CONTINUE THIS TREND INTO MIDDLE TENNESSEE FOR THE MORNING HOURS AND SHOW THE WHOLE AREA WITH A DEFINITE POP. WITH VERY LITTLE SHEAR ACCOMPANYING OR AHEAD OF THESE STORMS...WILL REFRAIN FROM ANY SEVERE WORDING TODAY. WHAT WE WILL HAVE TO ACCOUNT FOR THOUGH IS RAIN RATES. MODERATE TO HEAVY RAINFALL WILL ACCOMPANY THESE STORMS AS THEY MOVE THROUGH THE STATE TODAY. WHILE THERE ARE NO WIDESPREAD FLOODING OR FLASH FLOODING CONCERNS...00Z SOUNDINGS AND LATEST PW SATELLITE PRODUCTS DEPICT 1.9 TO 2.1 INCHES OF PW WILL BE IN PLACE TODAY. WITH STORM FLOW EXPECTED TO BE AT LEAST 15-20KTS...IT WILL BE THE TRAINING OF CELLS WE WILL HAVE TO MONITOR...AS 1.5 TO 2 INCHES OF RAINFALL COULD OCCUR IN A SHORT PERIOD OF TIME. THE REST OF THE FORECAST REMAINS GREATLY UNCHANGED WITH THIS PACKAGE. MULTIPLE SHORTWAVES TRAVERSING MOIST AND WARM BOUNDARY LAYER CONDITIONS WILL BRING SCATTERED SHOWERS AND THUNDERSTORMS THROUGH WEDNESDAY. WHILE I STILL DON`T SEE ANYTHING FROM ONE DAY TO THE NEXT TO WARRANT INCLUSION OF SEVERE WORDING IN THE HAZARDOUS WEATHER OUTLOOK...I COULD SEE A MARGINALLY SEVERE STORM OR TWO BEING POSSIBLE EACH OF THE NEXT 3 AFTERNOONS. TEMPERATURES WILL RUN A DEGREE OR TWO WITHIN NORMALS IN THIS PERIOD. WONDERFULLY DRY AIR WILL PUSH INTO THE STATE FOR THURSDAY AND FRIDAY. DEW POINTS IN THE LOW 60S AND NORTHERLY FLOW WILL HELP MAINTAIN NO CHANCE FOR RAIN THESE TWO DAYS. WHILE THE EURO TOOK A HIATUS ON THE YESTERDAY`S 12Z RUN...BOTH OF OUR LONG RANGE MODELS ARE BACK TO SHOWING A FAIRLY INTENSE AND UNSEASONABLE SHORTWAVE TROUGH MOVING INTO THE MID-MISSISSIPPI VALLEY SATURDAY. THE LOCATION AND EVENTUAL PATH OF THIS SYSTEM IS STILL GREATLY IN QUESTION...SO WILL HOLD ONTO CURRENT FORECAST IN REGARDS TO RAIN ON SATURDAY...BUT IF THIS PERSISTS IT MAY WARRANT AN INCREASED CHANCE OF PRECIPITATION IN FUTURE FORECASTS. UNGER AVIATION...06Z TAF DISCUSSION. UPPER TROUGH AXIS WILL APPROACH THE MIDDLE TN AREA FROM THE WEST OVERNIGHT AND ON MONDAY. AS DEEPER MOISTURE SPREAD ACROSS THE AREA TOWARD 12Z...WIDESPREAD SHOWER AND EMBEDDED THUNDERSTORM ACTIVITY IS EXPECTED TO RETURN FROM WEST TO EAST AFT 09Z. THIS ACTIVITY SHOULD EXIT THE CSV AREA AROUND 14Z- 16Z WITH A BREAK FROM THE CONVECTION UNTIL 18-20Z OR SO. PROB30`S WILL THEN BE INCLUDED FOR TSTMS DEVELOPMENT IN THE LATE AFTERNOON. PARTIAL CLEARING EXPECTED AFT 00Z EXCEPT FOR THE CSV AREA WHERE THE LOW CLOUDINESS SHOULD HANG ON. && .PRELIMINARY POINT TEMPS/POPS... NASHVILLE 87 72 91 72 / 90 30 50 30 CLARKSVILLE 86 70 91 70 / 40 30 50 30 CROSSVILLE 80 68 84 68 / 90 40 40 30 COLUMBIA 87 72 90 72 / 90 30 50 40 LAWRENCEBURG 87 71 89 71 / 90 40 50 40 WAVERLY 87 71 92 71 / 50 30 50 30 && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 01
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
922 AM CDT MON JUL 22 2013 .MESOSCALE UPDATE... ON-GOING GOOD RAIN EVENT ACROSS MIDDLE TENNESSEE. HEAVEIST RAINS HAVE BEEN FALLING OVER SOUTHWEST MIDDLE TENNESSEE WHERE GUIDANCE NUMBERS ARE QUITE A BIT HIGHER. THIS EVENT TIED TO UPPER LEVEL SHORT WAVE CURRENTLY OVER SOUTHERN ILLINOIS DOWN THROUGH EASTERN ARKANSAS. COLDER AIR IS GETTING INJECTED THROUGH THE MID AND UPPER LEVELS. AM EXPECTING BULK OF THE RAIN TO END WEST OF NASHVILLE BY NOON WITH ACTIVITY OVER EASTERN AREAS SCATTERING OUT DURING THE AFTERNOON. CLOUDS AND RAIN WILL HOLD TEMPS DOWN THIS MORNING BUT SHOULD HAVE ENOUGH TIME TO RECOVER THIS AFTERNOON. BOYD && .PREV DISCUSSION... /ISSUED 520 AM CDT MON JUL 22 2013/ UPDATE...ADDED AVIATION SECTION FOR 12Z TAF`S. AVIATION...BNA/CKV/CSV...UPPER TROUGH IS EXPECTED TO SWING THROUGH MIDDLE TENNESSEE TODAY, BRINGING WIDESPREAD CONVECTION TO THE MID STATE. WILL INCLUDE TEMPO GROUPS TO REFLECT BEST WINDOW OF OPPORTUNITY AT EACH SITE, AS THE WRF MODEL AND HRRR OUTPUT BOTH SHOW SOME ORGANIZATION WITH THE CONVECTION. FREQUENT LIGHTNING IS EXPECTED WITH THE STRONGEST OF THESE STORMS. OVERNIGHT, EXPECT FOG TO DEVELOP DUE TO PARTIAL RADIATIONAL COOLING. PREV DISCUSSION... /ISSUED 324 AM CDT MON JUL 22 2013/ DISCUSSION... THIS VERY WET PATTERN WE HAVE FALLEN VICTIM TO CONTINUES TODAY. IN RESPONSE TO A SHORTWAVE TROUGH THAT IS POSITIVELY TILTED FROM THE WESTERN GREAT LAKES SWWD INTO MISSOURI...A LARGE CLUSTER OF DISORGANIZED SHOWERS AND THUNDERSTORMS ARE PUSHING THROUGH THE MID-MISSISSIPPI VALLEY. WITH NO REASON TO EXPECT THEM TO BEGIN FALLING APART...WILL CONTINUE THIS TREND INTO MIDDLE TENNESSEE FOR THE MORNING HOURS AND SHOW THE WHOLE AREA WITH A DEFINITE POP. WITH VERY LITTLE SHEAR ACCOMPANYING OR AHEAD OF THESE STORMS...WILL REFRAIN FROM ANY SEVERE WORDING TODAY. WHAT WE WILL HAVE TO ACCOUNT FOR THOUGH IS RAIN RATES. MODERATE TO HEAVY RAINFALL WILL ACCOMPANY THESE STORMS AS THEY MOVE THROUGH THE STATE TODAY. WHILE THERE ARE NO WIDESPREAD FLOODING OR FLASH FLOODING CONCERNS...00Z SOUNDINGS AND LATEST PW SATELLITE PRODUCTS DEPICT 1.9 TO 2.1 INCHES OF PW WILL BE IN PLACE TODAY. WITH STORM FLOW EXPECTED TO BE AT LEAST 15-20KTS...IT WILL BE THE TRAINING OF CELLS WE WILL HAVE TO MONITOR...AS 1.5 TO 2 INCHES OF RAINFALL COULD OCCUR IN A SHORT PERIOD OF TIME. THE REST OF THE FORECAST REMAINS GREATLY UNCHANGED WITH THIS PACKAGE. MULTIPLE SHORTWAVES TRAVERSING MOIST AND WARM BOUNDARY LAYER CONDITIONS WILL BRING SCATTERED SHOWERS AND THUNDERSTORMS THROUGH WEDNESDAY. WHILE I STILL DON`T SEE ANYTHING FROM ONE DAY TO THE NEXT TO WARRANT INCLUSION OF SEVERE WORDING IN THE HAZARDOUS WEATHER OUTLOOK...I COULD SEE A MARGINALLY SEVERE STORM OR TWO BEING POSSIBLE EACH OF THE NEXT 3 AFTERNOONS. TEMPERATURES WILL RUN A DEGREE OR TWO WITHIN NORMALS IN THIS PERIOD. WONDERFULLY DRY AIR WILL PUSH INTO THE STATE FOR THURSDAY AND FRIDAY. DEW POINTS IN THE LOW 60S AND NORTHERLY FLOW WILL HELP MAINTAIN NO CHANCE FOR RAIN THESE TWO DAYS. WHILE THE EURO TOOK A HIATUS ON THE YESTERDAY`S 12Z RUN...BOTH OF OUR LONG RANGE MODELS ARE BACK TO SHOWING A FAIRLY INTENSE AND UNSEASONABLE SHORTWAVE TROUGH MOVING INTO THE MID-MISSISSIPPI VALLEY SATURDAY. THE LOCATION AND EVENTUAL PATH OF THIS SYSTEM IS STILL GREATLY IN QUESTION...SO WILL HOLD ONTO CURRENT FORECAST IN REGARDS TO RAIN ON SATURDAY...BUT IF THIS PERSISTS IT MAY WARRANT AN INCREASED CHANCE OF PRECIPITATION IN FUTURE FORECASTS. UNGER AVIATION...06Z TAF DISCUSSION. UPPER TROUGH AXIS WILL APPROACH THE MIDDLE TN AREA FROM THE WEST OVERNIGHT AND ON MONDAY. AS DEEPER MOISTURE SPREAD ACROSS THE AREA TOWARD 12Z...WIDESPREAD SHOWER AND EMBEDDED THUNDERSTORM ACTIVITY IS EXPECTED TO RETURN FROM WEST TO EAST AFT 09Z. THIS ACTIVITY SHOULD EXIT THE CSV AREA AROUND 14Z- 16Z WITH A BREAK FROM THE CONVECTION UNTIL 18-20Z OR SO. PROB30`S WILL THEN BE INCLUDED FOR TSTMS DEVELOPMENT IN THE LATE AFTERNOON. PARTIAL CLEARING EXPECTED AFT 00Z EXCEPT FOR THE CSV AREA WHERE THE LOW CLOUDINESS SHOULD HANG ON. && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 01
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
520 AM CDT MON JUL 22 2013 .UPDATE...ADDED AVIATION SECTION FOR 12Z TAF`S. && .AVIATION...BNA/CKV/CSV...UPPER TROUGH IS EXPECTED TO SWING THROUGH MIDDLE TENNESSEE TODAY, BRINGING WIDESPREAD CONVECTION TO THE MID STATE. WILL INCLUDE TEMPO GROUPS TO REFLECT BEST WINDOW OF OPPORTUNITY AT EACH SITE, AS THE WRF MODEL AND HRRR OUTPUT BOTH SHOW SOME ORGANIZATION WITH THE CONVECTION. FREQUENT LIGHTNING IS EXPECTED WITH THE STRONGEST OF THESE STORMS. OVERNIGHT, EXPECT FOG TO DEVELOP DUE TO PARTIAL RADIATIONAL COOLING. && .PREV DISCUSSION... /ISSUED 324 AM CDT MON JUL 22 2013/ DISCUSSION... THIS VERY WET PATTERN WE HAVE FALLEN VICTIM TO CONTINUES TODAY. IN RESPONSE TO A SHORTWAVE TROUGH THAT IS POSITIVELY TILTED FROM THE WESTERN GREAT LAKES SWWD INTO MISSOURI...A LARGE CLUSTER OF DISORGANIZED SHOWERS AND THUNDERSTORMS ARE PUSHING THROUGH THE MID-MISSISSIPPI VALLEY. WITH NO REASON TO EXPECT THEM TO BEGIN FALLING APART...WILL CONTINUE THIS TREND INTO MIDDLE TENNESSEE FOR THE MORNING HOURS AND SHOW THE WHOLE AREA WITH A DEFINITE POP. WITH VERY LITTLE SHEAR ACCOMPANYING OR AHEAD OF THESE STORMS...WILL REFRAIN FROM ANY SEVERE WORDING TODAY. WHAT WE WILL HAVE TO ACCOUNT FOR THOUGH IS RAIN RATES. MODERATE TO HEAVY RAINFALL WILL ACCOMPANY THESE STORMS AS THEY MOVE THROUGH THE STATE TODAY. WHILE THERE ARE NO WIDESPREAD FLOODING OR FLASH FLOODING CONCERNS...00Z SOUNDINGS AND LATEST PW SATELLITE PRODUCTS DEPICT 1.9 TO 2.1 INCHES OF PW WILL BE IN PLACE TODAY. WITH STORM FLOW EXPECTED TO BE AT LEAST 15-20KTS...IT WILL BE THE TRAINING OF CELLS WE WILL HAVE TO MONITOR...AS 1.5 TO 2 INCHES OF RAINFALL COULD OCCUR IN A SHORT PERIOD OF TIME. THE REST OF THE FORECAST REMAINS GREATLY UNCHANGED WITH THIS PACKAGE. MULTIPLE SHORTWAVES TRAVERSING MOIST AND WARM BOUNDARY LAYER CONDITIONS WILL BRING SCATTERED SHOWERS AND THUNDERSTORMS THROUGH WEDNESDAY. WHILE I STILL DON`T SEE ANYTHING FROM ONE DAY TO THE NEXT TO WARRANT INCLUSION OF SEVERE WORDING IN THE HAZARDOUS WEATHER OUTLOOK...I COULD SEE A MARGINALLY SEVERE STORM OR TWO BEING POSSIBLE EACH OF THE NEXT 3 AFTERNOONS. TEMPERATURES WILL RUN A DEGREE OR TWO WITHIN NORMALS IN THIS PERIOD. WONDERFULLY DRY AIR WILL PUSH INTO THE STATE FOR THURSDAY AND FRIDAY. DEW POINTS IN THE LOW 60S AND NORTHERLY FLOW WILL HELP MAINTAIN NO CHANCE FOR RAIN THESE TWO DAYS. WHILE THE EURO TOOK A HIATUS ON THE YESTERDAY`S 12Z RUN...BOTH OF OUR LONG RANGE MODELS ARE BACK TO SHOWING A FAIRLY INTENSE AND UNSEASONABLE SHORTWAVE TROUGH MOVING INTO THE MID-MISSISSIPPI VALLEY SATURDAY. THE LOCATION AND EVENTUAL PATH OF THIS SYSTEM IS STILL GREATLY IN QUESTION...SO WILL HOLD ONTO CURRENT FORECAST IN REGARDS TO RAIN ON SATURDAY...BUT IF THIS PERSISTS IT MAY WARRANT AN INCREASED CHANCE OF PRECIPITATION IN FUTURE FORECASTS. UNGER AVIATION...06Z TAF DISCUSSION. UPPER TROUGH AXIS WILL APPROACH THE MIDDLE TN AREA FROM THE WEST OVERNIGHT AND ON MONDAY. AS DEEPER MOISTURE SPREAD ACROSS THE AREA TOWARD 12Z...WIDESPREAD SHOWER AND EMBEDDED THUNDERSTORM ACTIVITY IS EXPECTED TO RETURN FROM WEST TO EAST AFT 09Z. THIS ACTIVITY SHOULD EXIT THE CSV AREA AROUND 14Z- 16Z WITH A BREAK FROM THE CONVECTION UNTIL 18-20Z OR SO. PROB30`S WILL THEN BE INCLUDED FOR TSTMS DEVELOPMENT IN THE LATE AFTERNOON. PARTIAL CLEARING EXPECTED AFT 00Z EXCEPT FOR THE CSV AREA WHERE THE LOW CLOUDINESS SHOULD HANG ON. && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ ROSE
AREA FORECAST DISCUSSION
NWS EL PASO TX/SANTA TERESA NM
133 PM MDT MON JUL 22 2013 .SYNOPSIS... WE CAN EXPECT A WEAK MONSOONAL PATTERN FOR MOST OF THE WORK WEEK. IN THIS CASE THE PATTERN FAVORS HEAVIER RAINFALL FOR AREAS FROM THE CONTINENTAL DIVIDE WEST...BUT AFTERNOON OR NIGHTTIME THUNDERSTORMS ARE POSSIBLE ANYWHERE IN THE FORECAST AREA EACH AFTERNOON AND EVENING. FOR THE WEEKEND...A BACKDOOR COLD FRONT WILL FRILT WITH OUR AREA WHICH SHOULD SERVE TO DRAW ADDITIONAL TROPICAL MOISTURE INTO THE REGION AND RESULT IN AN INCREASED CHANCE OF SHOWERS AND THUNDERSTORMS. TEMPERATURES DURING UPCOMING WEEK WILL RUN WITH A FEW DEGREES OF NORMAL. && .DISCUSSION... UPPER HIGH IS BEGINNING TO BUILD EAST TO COVER THE CWA FOR THE UPCOMING WEEK. INVERTED TROUGH SLIDING WEST OVER NORTHERN MEXICO MAY PROVIDE A LITTLE EXTRA DYNAMICS/MOISTURE OVER THE SOUTHERN TIER. LAST AVBL HRRR AND 12Z SPC 4KM RUN BOTH SHOW CLUSTER OF STORMS IMPACTING SW PORTIONS OF AREA TONIGHT...SO HAVE RAISED POPS IN THAT AREA, OTHERWISE EXPECT MAINLY A LOW GRADE MONSOONAL PATTERN THROUGH DAYTIME FRIDAY. THERE MAY BE AN UPTICK OF CONVECTION WEDNESDAY WHERE THE ORIENTATION OF THE UPPER HIGH AND THE INVERTED TROUGH ALLOWS A LITTLE EXTRA MOISTURE AND REDUCED STABILITY OVER THE AREA. THE LARGER QUESTION FOR ME IS WHETHER A BACKDOOR FRONT MAKES IT INTO THE AREA FOR THE WEEKEND. WEEKEND RUNS OF THE GFS/ECMWF WERE VERY AGGRESSIVE IN BRINGING THE FRONT INTO THE AREA. LATER RUNS OF THE GFS IN PARTICULAR HAVE BACKED AWAY FROM FROPA OVER THE AREA... HOWEVER CMC 12Z RUN STILL HAS A STRONG PASSAGE. SINCE I HAVE LITTLE TRUST IN GFS HANDLING OF BACKDOORS THIS FAR OUT AND THAT SURFACE TROUGHING WILL ALLOW A CHANNEL OF MOISTURE TO MOVE TOWARD THE FRONT REGARDLESS OF ITS FINAL POSITION...I HAVE BUMPED POPS UP FOR THE WEEKEND AFTERNOONS. IF THE FRONT MAKES IT INTO THE REGION THERE WOULD LIKELY BE AN INCREASE FLOOD RISK AND POSSIBLE SEVERE WEATHER AS WELL. && .AVIATION...VALID 23/00Z-24/00Z. SCATTERED TSRA THRU 06Z OVER THE MOUNTAINS WITH ISOLATED TO WIDELY SCATTERED TSRA IN THE LOWLANDS. STORMS WILL TEND TO DRIFT TOWARDS THE W OR WSW. MOSTLY VFR CONDITIONS ARE EXPECTED WITH THE EXCEPTION OF BRIEF EXCURSIONS INTO MVFR/IFR CONDITIONS IN AND AROUND THUNDERSTORMS. && .FIRE WEATHER... A HIGH PRESSURE RIDGE ALOFT REMAINS ANCHORED OVER THE REGION WITH AMPLE LOW LEVEL MOISTURE IN PLACE AT THE SURFACE. THIS WILL RESULT IN SCATTERED TO WIDELY SCATTERED AFTERNOON AND EVENING THUNDERSTORMS THE NEXT SEVERAL DAYS. CLOSER INSPECTION REVEALS A WEAK UPPER DISTURBANCE TRACKING SLOWLY WESTWARD TO OUR SOUTH ACROSS NORTHERN MEXICO. THIS WILL LIKELY ENHANCE STORM CHANCES NEAR THE INTERNATIONAL BORDER AND AREAS WEST OF THE RIO GRANDE THIS EVENING AND TONIGHT. THIS FEATURE WILL EVENTUALLY EXUDE IT`S INFLUENCE FURTHER NORTH INTO THE REGION MID TO LATE WEEK AS THE RIDGE BEGINS TO WEAKEN. AS A RESULT A GREATER COVERAGE OF WETTING RAINFALL WILL BE POSSIBLE AREA WIDE. THIS TREND WILL CONTINUE INTO THE WEEKEND. WITH LOW LEVEL MOIST AIR IN PLACE MINIMUM RH VALUES WILL CONTINUE TO RUN AROUND 30 PERCENT FOR THE LOWLANDS AND BETWEEN 40 AND 50 PERCENT ACROSS THE HIGHER ELEVATIONS WITH EXCELLENT RECOVERIES OVERNIGHT FOR THE NEXT SEVERAL DAYS. MEANWHILE HAINES INDICES WILL REMAIN LOW TO VERY LOW ACROSS THE REGION. && .PRELIMINARY POINT TEMPS/POPS... EL PASO 73 93 75 93 75 / 30 20 20 20 30 SIERRA BLANCA 69 91 71 92 71 / 30 20 20 30 20 LAS CRUCES 70 93 71 91 70 / 30 20 20 20 40 ALAMOGORDO 70 95 72 95 71 / 30 20 20 30 40 CLOUDCROFT 50 71 52 71 52 / 30 30 20 40 40 TRUTH OR CONSEQUENCES 69 94 71 93 70 / 30 20 20 30 40 SILVER CITY 64 85 65 85 62 / 40 40 30 30 40 DEMING 69 92 70 91 68 / 30 20 20 20 40 LORDSBURG 67 91 69 91 66 / 30 30 30 30 40 WEST EL PASO METRO 74 93 76 92 75 / 30 20 20 20 30 DELL CITY 68 94 69 95 69 / 20 10 20 20 30 FORT HANCOCK 73 94 73 95 73 / 30 20 30 30 30 LOMA LINDA 65 88 66 88 67 / 40 20 20 20 30 FABENS 71 92 73 93 73 / 40 20 30 20 30 SANTA TERESA 71 92 71 91 71 / 40 20 20 20 30 WHITE SANDS HQ 72 94 74 93 74 / 40 20 20 20 30 JORNADA RANGE 66 94 68 93 67 / 40 20 20 20 40 HATCH 70 91 73 89 71 / 30 20 20 20 40 COLUMBUS 69 91 70 90 69 / 40 20 20 20 40 OROGRANDE 69 95 70 95 73 / 30 20 20 20 30 MAYHILL 57 81 59 80 59 / 30 40 20 30 40 MESCALERO 56 85 56 84 56 / 30 30 20 40 40 TIMBERON 57 78 58 78 58 / 30 30 20 30 40 WINSTON 59 84 61 85 60 / 30 30 30 30 40 HILLSBORO 66 89 68 87 67 / 30 30 30 30 40 SPACEPORT 69 94 69 92 68 / 30 20 20 20 30 LAKE ROBERTS 61 85 62 85 60 / 40 50 30 40 50 HURLEY 64 87 65 86 63 / 40 30 30 30 40 CLIFF 65 92 66 92 62 / 30 40 40 30 40 MULE CREEK 58 88 59 88 58 / 30 40 40 40 40 FAYWOOD 65 86 68 87 64 / 30 30 30 30 40 ANIMAS 67 89 68 89 66 / 30 30 30 30 40 HACHITA 68 89 68 89 66 / 30 30 20 20 40 ANTELOPE WELLS 66 86 66 85 66 / 30 30 30 30 40 CLOVERDALE 63 81 64 80 64 / 40 40 30 40 50 && .EPZ WATCHES/WARNINGS/ADVISORIES... NM...NONE. TX...NONE. && $$ 02/27
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
121 AM EDT MON JUL 22 2013 .SYNOPSIS... A WEAK STATIONARY FRONT ACROSS THE SOUTHERN OHIO VALLEY WILL REMAIN IN PLACE INTO MONDAY EVENING BEFORE DISSIPATING. AN UPPER LEVEL DISTURBANCE WILL TRACK EAST CROSSING THE REGION LATER MONDAY NIGHT AND EARLY TUESDAY. DEEP MOISTURE IN ASSOCIATION WITH THESE FEATURES WILL KEEP ROUNDS OF SHOWERS AND THUNDERSTORMS GOING EARLY THIS WEEK. && .NEAR TERM /THROUGH TODAY/... AS OF 1000 PM EDT SUNDAY... FOLLOWING CLOSE TO THE HRRR WHICH HIGHLIGHTS MORE THREAT OF SHOWERS FROM SE WV EAST NORTHEAST INTO THE SOUTHERN SHENANDOAH VALLEY OVERNIGHT BEFORE DIMINISHING. KEPT ISOLATED TO NONE IN THE SOUTH. NOT MUCH CHANGE IN THE REST OF THE FORECAST AS WE SHOULD SEE PATCHY FOG WITH MOSTLY CLOUDY SKIES. OVERNIGHT LOWS WILL REMAIN ON THE MILD SIDE...GENERALLY FALLING INTO THE MID 60S TO LOW 70S. EXPECT GREATER COVERAGE OF SHOWER AND THUNDERSTORM ACTIVITY FOR MONDAY AS A STRONGER UPPER LEVEL DISTURBANCE APPROACHES FROM THE WEST. ONCE AGAIN...THE GREATEST THREAT NORTH OF INTERSTATE 81 WILL BE LOCALLY HEAVY RAIN...WITH RAINFALL RATES OF AN INCH OR MORE OVER A FEW MINUTES TIME. AS SUCH...WILL AGAIN BE CONCERNED WITH LOCALIZED FLASH FLOODING. WILL LEAVE THE DECISION OF THE TIMING AND LOCATION OF A FLASH FLOOD WATCH TO THE OVERNIGHT SHIFT...GIVING THEM AN OPPORTUNITY TO LOOK AT ANOTHER SET OF SYNOPTIC WEATHER MODELS. SOUTH OF INTERSTATE 81...WILL ALSO SEE A SLIGHTLY GREATER THREAT OF STRONG TO SEVERE THUNDERSTORMS DURING THE AFTERNOON AND EVENING DUE TO STRONGER SURFACE HEATING. STUCK PRETTY CLOSE TO MET GUIDANCE FOR AFTERNOON TEMPERATURES...WITH HIGHS REACHING THE UPPER 70S AND LOW 80S WEST...AND REACHING TO AROUND 90 ACROSS THE PIEDMONTS. && .SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/... AS OF 340 PM EDT SUNDAY... WELL DEFINED SHORT WAVE CROSSES THE FORECAST AREA MONDAY NIGHT AND TUESDAY. THIS WILL KEEP A BETTER PROBABILITY OF PRECIPITATION OVERNIGHT THAN JUST THE TYPICAL DIURNAL CYCLE OF THE PAST FEW DAYS. UPPER TROF AMPLIFIES ENOUGH THAT THE FRONT WILL PUSH SOUTH OF THE FORECAST AREA ON WEDNESDAY. AS THE FRONT COMES THROUGH ON WEDNESDAY THE EXPECTING MORE AREAL COVERAGE OF SHOWERS AND THUNDERSTORMS IN THE AFTERNOON AND EVENING. WITH THE PASSAGE OF THE SHORT WAVE...MID LEVEL TEMPERATURES COOL SLIGHTLY WHICH WILL ENHANCE THE LAPSE RATES AND INSTABILITY. LITTLE CHANGE IN DAILY HIGH AND LOW TEMPERATURES AND IN MOISTURE OF THE AIR MASS. STAYED CLOSE TO MODEL GUIDANCE FOR MAXIMUM AND MINIMUM TEMPERATURES EACH DAY. && .LONG TERM /THURSDAY THROUGH SUNDAY/... AS OF 1140 AM EDT SUNDAY... NO CHANGE IN THE OVERALL PATTERN THROUGH THE EXTENDED PERIOD. MODELS BRINGING STRONG ENOUGH SHORT WAVE THROUGH THE EASTERN UPPER TROF ON THURSDAY TO PUSH A SURFACE FRONT INTO THE SOUTHEAST STATES. THIS WOULD BRING WINDS AROUND TO THE NORTHWEST AND NORTH. MAY NOT COMPLETELY ELIMINATE THE PROBABILITY OF PRECIPITATION FOR THE FORECAST AREA...BUT CHANCES ON THURSDAY AND FRIDAY SHOULD BE LESS THAN IN RECENT DAYS. SOME SIGNS IN THE MODELS OF ACTUAL DRIER AIR REACHING THE FORECAST AREA. SUBTLE DROP IN 850 MB TEMPERATURES BEHIND THE FRONT...OTHERWISE NEAR NORMAL FOR HIGHS AND LOWS THROUGH DAY 7/SUNDAY. SURFACE LOW PRESSURE OVER THE MISSISSIPPI VALLEY ON SATURDAY WILL APPROACH THE REGION BY SUNDAY. WINDS WILL BE BACK AROUND TO THE SOUTHWEST WITH DEEP MOISTURE RETURNING AHEAD OF THE LOW. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... AS OF 1250 AM EDT MONDAY... EARLIER SHOWERS HAVE ALL BUT FADED EXCEPT ACROSS THE GREENBRIER VALLEY WHERE A CLUSTER REMAINS MAINLY JUST WEST OF KLWB. EXPECT THIS PRECIP TO SLOWLY EXIT TO THE NORTH IN THE NEXT HOUR LEAVING AREAS OF LOW CLOUDS AND FOG WHICH SHOULD DROP KLWB TO IFR/LIFR IN THE NEXT COUPLE OF HOURS. ELSW LINGERING DEBRIS MID DECK MAY TEND TO LIMIT FOG FORMATION INITIALLY BUT EXPECT ENOUGH THINNING OVERNIGHT TO ALLOW AREAS OF DENSE FOG ESPCLY EAST WHERE EARLIER MORE WIDESPREAD HEAVY RAINFALL OCCURRED. THUS STILL THINKING MVFR WITH MORE IFR EAST AND AROUND KBCB...WITH POTENTIAL LOW CIGS AT KBLF. COVERAGE OF SHOWERS AND STORMS LOOKS BETTER MONDAY AND EVEN THOUGH THIS IS LIKELY...KEPT VCTS IN THE TAFS AND PREDOMINAT SHOWERS...AS MODELS STILL SHOWING AT LEAST SOME PERIODS OF LESS COVERAGE MAINLY EAST OF THE BLUE RIDGE EARLY ON. MAIN CONCERNS WITH THIS DISTURBANCE WILL AGAIN BE HEAVY RAIN...RESULTING IN PERIODIC IFR CONDITIONS AT ALL AIRPORTS. A FEW SEVERE STORMS WILL ALSO BE POSSIBLE...MORE SO FOR KDAN AND KLYH WHERE STRONGER DAYTIME HEATING WILL ADD TO ATMOSPHERIC INSTABILITY DURING THE AFTERNOON. SHOWERS MAY LINGER INTO MONDAY EVENING WITH THE ACTUAL TROF AXIS CROSSING THE REGION DESPITE LOSS OF HEATING SO EXTENDING SHRA MENTION AT MOST LOCATIONS PAST SUNSET. MODELS CONTINUE TO DEPICT THE STALLED FRONT HOLDING JUST NORTH OF THE AREA THROUGH EARLY TUESDAY...BEFORE LIFTING AS A LOW PRESSURE SYSTEM MOVES ACROSS THE WESTERN GREAT LAKES. REGARDLESS...EXPECT DIURNALLY DRIVEN SHOWERS AND THUNDERSTORMS TO PERSIST THROUGH THE COMING WORKWEEK AS GULF MOISTURE REMAINS ABUNDANT ACROSS THE AREA. ANOTHER COLD FRONT WILL APPROACH THE OHIO RIVER TOWARD THE END OF THE WORKWEEK...BUT DO NOT SEE THE FRONT ADVANCING MUCH FURTHER SOUTH THAN THAT. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...JH/NF NEAR TERM...NF/WP SHORT TERM...AMS/RCS LONG TERM...AMS AVIATION...JH/NF/WP
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1008 PM CDT TUE JUL 23 2013 UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE .SHORT TERM...TONIGHT AND WEDNESDAY ISSUED AT 224 PM CDT TUE JUL 23 2013 LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW YESTERDAYS COLD FRONT HEADED FOR THE OHIO VALLEY WHILE CANADIAN HIGH PRESSURE IS MOVING SOUTHEAST OVER THE NORTHERN PLAINS. COLD ADVECTION IS OCCURRING BEHIND THE FRONT OVER THE WESTERN GREAT LAKES AND THE THERMAL TROUGHING IS CONTRIBUTING TO A WIDESPREAD STRATO-CU FIELD ACROSS MOST OF THE STATE. LOOKING UPSTREAM...A FEW SHORTWAVES NOTED OVER SASKATCHEWAN AND CENTRAL MANITOBA...WHERE CU LOOKS RATHER BUBBLY BUT NO LIGHTNING STRIKES SO FAR THIS AFTERNOON. AS HIGH PRESSURE BUILDS INTO THE REGION TONIGHT...CLOUDS AND TEMPS WILL BE THE MAIN FORECAST CONCERNS FOLLOWED BY SHOWER CHANCES TOMORROW. TONIGHT...HIGH PRESSURE WILL SHIFT SOUTHEAST TOWARDS WESTERN GREAT LAKES. GUSTY NORTH WINDS WILL PERSIST ALONG THE LAKE SHORE LONGER THAN NORTH-CENTRAL WISCONSIN...BUT SHOULD ALSO DIMINISH LATE IN THE NIGHT. AS WINDS DROP OFF...GOOD RADIATIONAL COOLING CONDITIONS WILL SETUP...THOUGH PATCHES OF MID-CLOUDS MAY ARRIVE AFTER LATE IN THE EVENING OR AFTER MIDNIGHT. THE COLD SPOTS COULD REACH THE LOWER 40S...WHILE MOST AREAS WILL RANGE FROM THE MID 40S TO LOW 50S. PATCHY FOG WILL ALSO BE POSSIBLE LATE TONIGHT AS WELL. WEDNESDAY...HIGH PRESSURE WILL REMAIN ACROSS THE AREA. WEAK SHORTWAVES WILL BE DIVING TOWARDS WISCONSIN WITHIN NORTHWEST FLOW ALOFT. CONVECTIVE TEMPS ARE PRETTY LOW TOMORROW...IN THE UPPER 60S TO LOWER 70S. COMBINED WITH WEAK FORCING ALOFT...THAT SHOULD BE ENOUGH TO PRODUCE A GOOD CU FIELD BY LATE MORNING. PROGGED INSTABILITY TOMORROW AFTERNOON WILL BE AROUND 100 J/KG...BUT THERE IS A SIZABLE CAP AROUND 625MB THAT WILL BE TOUGH TO OVERCOME. STILL...CU SHOULD BE DEEP ENOUGH FOR A WIDELY SCT TO LOW END SCT OF SHOWERS OVER THE HIGHER TERRAIN OF N-C WISCONSIN. PERHAPS AN ISOLATED RUMBLE OF THUNDER IS POSSIBLE. HIGHS WILL BE RATHER UNIFORM IN THE LOW TO MID 70S. .LONG TERM...WEDNESDAY NIGHT THROUGH TUESDAY ISSUED AT 224 PM CDT TUE JUL 23 2013 UPPER AIR PATTERN CHARACTERIZED BY WESTERN RIDGE AND GREAT LAKES TROF WILL DOMINATE THE WEATHER PATTERN DURING THE PERIOD. SHORTWAVE TROFS WILL AMPLIFY MEAN TROF OVER GREAT LAKES LATER THIS WEEK INTO WEEKEND. CLOSED LOW FORECAST TO DEVELOP WHICH WILL KEEP COOL AIR IN PLACE INTO EARLY NEXT WEEK. BEST CHANCE FOR RAIN WILL BE LATE THURSDAY INTO FRIDAY AS STRONGEST OF THE SHORTWAVE TROFS MOVE ACROSS AREA. SURFACE LOW PRESSURE AND COLD FRONT WILL PUSH ACROSS AREA WITH CONVECTION EXPECTED GIVEN INSTABILITY AND SHEAR. WARM AIR ADVECTION AHEAD OF APPROACHING SYSTEM COULD PUSH PRECIP INTO AREA AS EARLY AS LATE WEDNESDAY NIGHT/EARLY THURSDAY. TEMPS DURING MUCH OF PERIOD WILL REMAIN BELOW NORMAL. ON SATURDAY...HIGHS ONLY IN THE 60S ACROSS MUCH OF AREA. && .AVIATION...FOR 06Z TAF ISSUANCE ISSUED AT 1007 PM CDT TUE JUL 23 2013 CLEAR SKIES EARLY TONIGHT WILL BE REPLACED BY INCREASING MID/HIGH LEVEL CLOUDS FROM THE NORTHWEST OVERNIGHT. PATCHY FOG POSSIBLE BETWEEN 09Z-12Z. MID LEVEL CLOUDS WILL CONTINUE TO INCREASE FROM THE NORTH ON WEDNESDAY IN THE NORTHWEST FLOW. WIDELY SCT SHOWERS OVER NORTHERN WISCONSIN FOR WEDNESDAY AFTERNOON. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....MPC LONG TERM......JKL AVIATION.......TDH
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
622 PM CDT TUE JUL 23 2013 UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE .SHORT TERM...TONIGHT AND WEDNESDAY ISSUED AT 224 PM CDT TUE JUL 23 2013 LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW YESTERDAYS COLD FRONT HEADED FOR THE OHIO VALLEY WHILE CANADIAN HIGH PRESSURE IS MOVING SOUTHEAST OVER THE NORTHERN PLAINS. COLD ADVECTION IS OCCURRING BEHIND THE FRONT OVER THE WESTERN GREAT LAKES AND THE THERMAL TROUGHING IS CONTRIBUTING TO A WIDESPREAD STRATO-CU FIELD ACROSS MOST OF THE STATE. LOOKING UPSTREAM...A FEW SHORTWAVES NOTED OVER SASKATCHEWAN AND CENTRAL MANITOBA...WHERE CU LOOKS RATHER BUBBLY BUT NO LIGHTNING STRIKES SO FAR THIS AFTERNOON. AS HIGH PRESSURE BUILDS INTO THE REGION TONIGHT...CLOUDS AND TEMPS WILL BE THE MAIN FORECAST CONCERNS FOLLOWED BY SHOWER CHANCES TOMORROW. TONIGHT...HIGH PRESSURE WILL SHIFT SOUTHEAST TOWARDS WESTERN GREAT LAKES. GUSTY NORTH WINDS WILL PERSIST ALONG THE LAKE SHORE LONGER THAN NORTH-CENTRAL WISCONSIN...BUT SHOULD ALSO DIMINISH LATE IN THE NIGHT. AS WINDS DROP OFF...GOOD RADIATIONAL COOLING CONDITIONS WILL SETUP...THOUGH PATCHES OF MID-CLOUDS MAY ARRIVE AFTER LATE IN THE EVENING OR AFTER MIDNIGHT. THE COLD SPOTS COULD REACH THE LOWER 40S...WHILE MOST AREAS WILL RANGE FROM THE MID 40S TO LOW 50S. PATCHY FOG WILL ALSO BE POSSIBLE LATE TONIGHT AS WELL. WEDNESDAY...HIGH PRESSURE WILL REMAIN ACROSS THE AREA. WEAK SHORTWAVES WILL BE DIVING TOWARDS WISCONSIN WITHIN NORTHWEST FLOW ALOFT. CONVECTIVE TEMPS ARE PRETTY LOW TOMORROW...IN THE UPPER 60S TO LOWER 70S. COMBINED WITH WEAK FORCING ALOFT...THAT SHOULD BE ENOUGH TO PRODUCE A GOOD CU FIELD BY LATE MORNING. PROGGED INSTABILITY TOMORROW AFTERNOON WILL BE AROUND 100 J/KG...BUT THERE IS A SIZABLE CAP AROUND 625MB THAT WILL BE TOUGH TO OVERCOME. STILL...CU SHOULD BE DEEP ENOUGH FOR A WIDELY SCT TO LOW END SCT OF SHOWERS OVER THE HIGHER TERRAIN OF N-C WISCONSIN. PERHAPS AN ISOLATED RUMBLE OF THUNDER IS POSSIBLE. HIGHS WILL BE RATHER UNIFORM IN THE LOW TO MID 70S. .LONG TERM...WEDNESDAY NIGHT THROUGH TUESDAY ISSUED AT 224 PM CDT TUE JUL 23 2013 UPPER AIR PATTERN CHARACTERIZED BY WESTERN RIDGE AND GREAT LAKES TROF WILL DOMINATE THE WEATHER PATTERN DURING THE PERIOD. SHORTWAVE TROFS WILL AMPLIFY MEAN TROF OVER GREAT LAKES LATER THIS WEEK INTO WEEKEND. CLOSED LOW FORECAST TO DEVELOP WHICH WILL KEEP COOL AIR IN PLACE INTO EARLY NEXT WEEK. BEST CHANCE FOR RAIN WILL BE LATE THURSDAY INTO FRIDAY AS STRONGEST OF THE SHORTWAVE TROFS MOVE ACROSS AREA. SURFACE LOW PRESSURE AND COLD FRONT WILL PUSH ACROSS AREA WITH CONVECTION EXPECTED GIVEN INSTABILITY AND SHEAR. WARM AIR ADVECTION AHEAD OF APPROACHING SYSTEM COULD PUSH PRECIP INTO AREA AS EARLY AS LATE WEDNESDAY NIGHT/EARLY THURSDAY. TEMPS DURING MUCH OF PERIOD WILL REMAIN BELOW NORMAL. ON SATURDAY...HIGHS ONLY IN THE 60S ACROSS MUCH OF AREA. && .AVIATION...FOR 00Z TAF ISSUANCE ISSUED AT 622 PM CDT TUE JUL 23 2013 CLEARING SKIES THIS EVENING WILL BE FOLLOWED BY AN INCREASE WITH PATCHY MID-LEVEL CLOUDS FROM THE NORTHWEST OVERNIGHT. MID LEVEL CLOUDS WILL CONTINUE TO INCREASE FROM THE NORTH ON WEDNESDAY. WIDELY SCT SHOWERS OVER NORTHERN WISCONSIN FOR WEDNESDAY AFTERNOON. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....MPC LONG TERM......JKL AVIATION.......TDH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
620 PM CDT TUE JUL 23 2013 .SHORT TERM...(TONIGHT AND WEDNESDAY) ISSUED AT 310 PM CDT TUE JUL 23 2013 MAIN FORECAST CONCERNS THIS PACKAGE...FOG POTENTIAL TONIGHT...LOWS TONIGHT/HIGHS WED. 18Z DATA ANALYSIS HAD AN AREA OF CANADIAN HIGH PRESSURE CENTERED NEAR THE ND/MAN BORDER...BUILDING STEADILY SOUTHEAST INTO THE NORTHERN PLAINS/WESTERN GREAT LAKES. DEW POINTS WITH THE HIGH/BEHIND MONDAYS FRONT HAVE DROPPED INTO THE MID 40S AND 50S OVER MUCH OF MN/WI/IA. COMBINED WITH TEMPS IN THE MID 60S TO MID 70S AND PARTLY- MOSTLY SUNNY SKIES...A SEASONABLY COOL...QUIET AND MORE COMFORTABLE JULY DAY IN PROGRESS ACROSS THE UPPER MIDWEST. 23.12Z MODELS LOOK TO HAVE INITIALIZED A BIT BETTER THAN AVERAGE AND OFFER QUITE SIMILAR SOLUTIONS AS THE CAN HIGH SLIPS ACROSS THE AREA TONIGHT AND MOISTURE/INSTABILITY STARTS TO RETURN ALREADY WED AFTERNOON. DPROG/DT OF 500MB HGTS AT 23.12Z SHOWED THE MODEL RUNS OF 21.12Z AND 22.12Z VERIFIED VERY WELL OVER NOAM/EASTERN PAC WITH A TREND TOWARD A COMPROMISE OF THE EARLIER RUNS. MODELS HOLD A TIGHT CONSENSUS TONIGHT/WED AS NORTHWEST FLOW ALOFT PERSISTS OVER THE REGION. TREND IS STRONGER WITH A SHORTWAVE TO TOP THE WESTERN NOAM RIDGE AND BE OVER CENTRAL ALB BY 00Z THU. THIS WITH LITTLE IMPACT ON THE FCST TONIGHT/WED BUT DOES FIGURE INTO THE FCST BY THU/FRI. CHECK OF OBS VS. MODEL DATA AT 18Z SHOWED ALL TO BE REASONABLE WITH THE ND/MAN HIGH AND THE DRIER AIR/LOWER DEW POINTS SPREADING INTO THE UPPER MIDWEST. PER WV IMAGERY MODELS GENERALLY LOOK GOOD WITH THE SHORTWAVE FEATURES OVER NOAM. HOWEVER PER THE VIS IMAGERY AND A MID CLOUD DECK OVER NORTHWEST MN...APPEARS TO BE A WEAK FEATURE OVER EASTERN ND/NORTHWEST MN THE MODELS ARE NOT CAPTURING WELL. DRIER OF MODELS GENERALLY BETTER WITH THE 12-18Z PRECIP OVER THE NORTH-CENTRAL CONUS...ESPECIALLY ND/SD AND IL/IN. NO CLEAR FAVORITE OUT OF THE GATE AND WITH SOLUTIONS VERY SIMILAR...USED THE MODEL/ ENSEMBLE CONSENSUS FOR THE SHORT TERM...WITH GOOD FCST CONFIDENCE. IN THE SHORT TERM...COOL...CAN HIGH ENDS UP CENTERED OVER WI/ SOUTHERN MN BY 12Z WED...PROVIDING A FAVORABLE SET UP FOR RADIATIONAL VALLEY FOG LATE TONIGHT. HOWEVER...PLENTY OF MID CLOUDS SEEN UPSTREAM OVER ND/NORTHWEST MN...ASSOCIATED WITH WEAK SHORTWAVE FEATURES TO DRIFT SOUTHEAST IN THE FLOW TONIGHT. NORTHERLY FLOW CONTINUES TO ADVECT DRIER AIR INTO THE AREA AS WELL WITH DEW POINTS IN THE UPPER 40S/LOW 50S ACROSS THE AREA. SOME DEW POINT RECOVERY EXPECTED EARLY THIS EVENING BUT GRADIENT WINDS LOOKING TO STAY IN THE 5-10 MPH RANGE THRU SUNSET. NOT EXPECTING A FULL VALLEY FOG EVENT DUE TO THE MID CLOUDS AND DRIER BOUNDARY LAYER AIR. WILL LEAVE PATCHY TO AREAS OF FOG IN THE MS AND TRIBUTARY RIVER VALLEYS...WITH MORE WIDESPREAD FOG IN THE MORE FOG-PRONE CENTRAL WI LOW LAYING AREAS AND WI RIVER VALLEY FOR LATER TONIGHT/EARLY WED MORNING. THE HIGH DRIFTS QUICKLY EAST WED...WITH MODELS SHOWING SOME 925- 850MB MOISTURE RETURN WEST OF THE MS RIVER FOR THE MID-LATE AFTERNOON HOURS. WEAK THETA-E CONVERGENCE AND 925-850MB WARM ADVECTION INDICATED AS WELL WITH PW VALUES IN THE 1 TO 1.25 INCH RANGE. EVEN WITH SFC DEW POINTS IN THE MID 50S...GFS PRODUCES 300- 500 J/KG OF ML CAPE OVER THE WEST HALF OF THE FCST AREA BY LATE WED AFTERNOON. INCLUDED AN ISOLATED SHRA/TSRA MENTION ACROSS THE WEST HALF OF THE FCST AREA LATE WED AFTERNOON AND NORTHWEST 1/3 EARLY WED EVENING. USED A BLEND OF THE NUMERICAL GUIDANCE FOR LOWS/HIGHS TONIGHT/WED. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 310 PM CDT TUE JUL 23 2013 FORECAST CONCERNS FOR WED NIGHT THRU FRI NIGHT ARE SHRA/TSRA CHANCES AND SEVERE POTENTIAL CENTERED ON THU/THU NIGHT WITH FRONTAL PASSAGE...TEMPERATURES THRU THE PERIOD. 23.12Z MODELS REMAIN IN GOOD AND IMPROVING CONSENSUS WED NIGHT INTO FRI NIGHT AS THE ALBERTA SHORTWAVE DROPS SOUTHEAST AND CARVES OUT A MID LEVEL LOW JUST NORTH OF LK SUPERIOR BY FRI NIGHT. THE STRONGER AND A SLIGHT SLOWING TREND WITH THIS FEATURE AT 00Z THU CONTINUES THRU FRI NIGHT. FCST CONFIDENCE IN THE WED NIGHT THRU FRI NIGHT PERIOD IS AVERAGE TO GOOD. 925-850MB MOISTURE TRANSPORT/WARM ADVECTION CONTINUE ACROSS THE NORTHWEST END OF THE FCST AREA AND STRENGTHEN A BIT LATER WED NIGHT/THU MORNING. MU CAPE IS MARGINAL UNTIL MID-DAY THU BUT WILL LEAVE A SMALL SHRA/TSRA CHANCE OVER THE NORTHWEST 1/3 OF THE FCST AREA FOR LATER WED NIGHT/THU MORNING. THE SLOWER EVOLUTION OF THE SYSTEM DOES 2 THINGS...DELAYS THE FRONT INTO THE AREA AND ALLOWS MORE TIME FOR MOISTURE TO RETURN NORTH AHEAD OF IT. WITH THE SLOWER FRONT...STRONGER OF LOWER LEVEL THERMO-DYNAMIC FORCING IS SLOWER TO ARRIVE IN THE AREA. HAVE REDUCED SHRA/TSRA CHANCES THU AFTERNOON AND CONFINED THEM TO MAINLY THE NORTHWEST HALF OF THE FCST AREA AFTER 21Z THU. MORE MOISTURE RETURN AHEAD OF THE FRONT ALLOWS FOR MORE ML/MU CAPE TO REMAIN OVER THE AREA THU NIGHT AS THE FRONT PUSHES INTO/ACROSS THE FCST AREA. RAISED SHRA/TSRA CHANCES TOWARD 50 PERCENT THU NIGHT AND IF PRESENT TRENDS CONTINUE THESE WOULD NEED TO BE RAISED TOWARD 70-80 PERCENT WITH LATER FCST PACKAGES. SLOWING OF THE FRONT HOLDS THE STRONGER CAPE/SHEAR AND FORCING WEST OF THE FCST AREA THU AFTERNOON/EVENING...WITH THE THREAT OF SEVERE STORMS DURING THIS PERIOD SHIFTED INTO SOUTHEAST SD THRU CENTRAL MN INTO FAR NORTHWEST WI THU AFTERNOON/EVENING. APPEARS BY THE TIME THE FRONT/STRONGER FORCING WOULD MOVE ACROSS THE FCST AREA...CAPE WOULD BE MARGINAL FOR SEVERE STORMS. PRESENT TIMING HAS THE FRONT BISECTING THE FCST AREA AT 12Z FRI. CONTINUED SHRA/TSRA CHANCES ACROSS MUCH OF THE AREA FRI MORNING WITH POTENTIAL FOR THE FRONT TO SLOW EVEN FURTHER. DID TREND SHRA/TSRA CHANCES DOWN FRI AFTERNOON AS ANOTHER STRONG PUSH OF COLDER AIR ON THE NOSE OF CANADIAN HIGH PRESSURE SPREADS IN BEHIND THE FRONT. MDT/STRONG LOW LEVEL COLD ADVECTION SPREADS ACROSS THE AREA FRI AFTERNOON. MUTED DIURNAL TEMP RISE EXPECTED FRI WITH CLOUDS/SHRA/ TSRA IN THE AREA IN THE MORNING THEN THE STRONGER COLD ADVECTION IN THE AFTERNOON. SOME SFC-700MB CYCLONIC FLOW REMAINS OVER THE AREA FRI NIGHT BUT SFC-850MB COOLING AND DRYING ABOVE 850MB CAP THE AIRMASS. LEFT FRI NIGHT DRY THOUGH CANNOT RULE OUT A FEW EARLY EVENING SHRA ACROSS THE FAR NORTH END OF THE FCST AREA UNDER THE COOLER TEMPS ALOFT. GENERALLY FAVORED A MODEL/ENSEMBLE CONSENSUS OF THE LOWS/HIGHS WED NIGHT THRU FRI NIGHT...EXCEPT FOR FRI. DID TREND FRI HIGHS A COUPLE DEGREES BELOW THE MODEL CONSENSUS. MEDIUM RANGE MODEL RUNS OF 23.00Z IN GOOD AGREEMENT WITH EACH OTHER AND THEIR PREVIOUS RUNS AS A COLD CORE MID LEVEL LOW SETS UP SHOP NORTH OF LK SUPERIOR. MODEL CONSISTENCY REMAINS RATHER GOOD SUN/MON. THIS AS THE LOW GRADUALLY LIFTS NORTHEAST MODEST RIDGING ALOFT BUILDS EAST ACROSS THE NORTHERN CONUS TOWARD THE REGION SUN...AS A SHORTWAVE MOVES ACROSS THE CENTRAL/NORTH PLAINS THRU THE RIDGING SUN NIGHT AND INTO THE UPPER MIDWEST MON. DIFFERENCES BEGIN TO APPEAR BY MON/ TUE...BUT RELATED TO TIMING/STRENGTH DETAILS OF THE NEXT SHORTWAVES INTO THE REGION THRU EITHER NORTHWEST OR QUASI-ZONAL FLOW. THESE DIFFERENCES NOT UNEXPECTED BY DAYS 6/7. OVERALL FCST CONFIDENCE IN THE DAY 4-7 PERIOD IS AVERAGE TO GOOD. SAT/SUN TRENDING COOL AND DRY AS THE SFC-MID LEVEL LOW CONTINUE MOVING NORTHEAST INTO ONT AND CAN HIGH PRESSURE SETTLES ACROSS THE REGION UNDER NORTHWEST TO NORTH FLOW ALOFT. SEASONABLY COOL AIRMASS SETTLES ACROSS MN/IA/WI FOR THE WEEKEND...WITH 850MB TEMP ANOMALIES SOME 1.5 TO 2 STANDARD DEVIATIONS BELOW NORMAL CENTERED ON SAT NIGHT. MID CREW FORECASTER BRIEFED ON POTENTIAL FOR SOME SUN MORNING LOWS IN THE UPPER 30S IN THE NORMALLY COLDER LOW LAYING AREAS ALONG/ NORTHEAST OF I-94. TEMPS BEGIN TO MODERATE MON/TUE AS HGTS RISE AND THE FLOW BECOMES MORE WESTERLY. WITH MODEST CONSENSUS FOR A SHORTWAVE TROUGH TO APPROACH/PASS MON/MON NIGHT AND SIGNAL FOR ANOTHER TO BE APPROACHING/IN THE REGION TUE...20-30 PERCENT SHRA/TSRA CHANCES FOR MUCH OF THE SUN NIGHT THRU TUE PERIOD...PER THE MODEL CONSENSUS... SEEMS REASONABLE. MODEL/ENSEMBLE CONSENSUS OF THE HIGHS/LOWS FOR SAT- TUE LOOK WELL TRENDED...THOUGH DID LOWER SAT NIGHT LOWS A BIT ALONG/ NORTHEAST OF I-94. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING) ISSUED AT 620 PM CDT TUE JUL 23 2013 HIGH PRESSURE CENTERED OVER NORTH DAKOTA WILL SLIDE SOUTHEAST AND BE OVER THE AREA TONIGHT. THIS WILL ALLOW THE WINDS TO DROP OFF TO LIGHT AND VARIABLE FOR BOTH SITES AND THE CONCERN THEN BECOMES WHETHER ANY VALLEY FOG WILL IMPACT KLSE. DEW POINTS ARE EXPECTED TO HOLD IN THE LOWER 50S AS SLIGHTLY DRIER AIR COMING IN FROM THE NORTH WILL BE COUNTERED BY THE DIURNAL EVENING INCREASE. WITH OVERNIGHT LOWS EXPECTED TO BE IN THE LOWER TO MIDDLE 50S APPEARS TO BE A GOOD SET UP FOR SOME FOG. HOWEVER...A SHORT WAVE TROUGH IN THE NORTHWEST FLOW ALOFT IS PRODUCING A BAND OF BROKEN MID LEVEL CLOUDS AND THESE ARE TIMED TO BE OVER THE AREA BEFORE SUNRISE. ALSO...NEITHER THE 23.18Z NAM OR 23.21Z RAP SHOW SATURATION OCCURRING AT THE SURFACE FOR KLSE. BASED ON THE CLOUDS AND CONCERN WHETHER SATURATION WILL OCCUR...WILL CONTINUE WITH VCFG FOR NOW. THE HIGH WILL SLIDE OFF TO THE SOUTHEAST WEDNESDAY ALLOWING THE WINDS TO COME AROUND TO THE SOUTH BUT REMAIN UNDER 10 KNOTS AS THE MID LEVEL CLOUDS CLEAR OUT BY MID MORNING. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...RRS LONG TERM...RRS AVIATION...04
AREA FORECAST DISCUSSION...UPDATED
NWS GREEN BAY WI
408 PM CDT MON JUL 22 2013 NEW INFORMATION ADDED TO UPDATE SECTION .UPDATE... ISSUED AT 407 PM CDT MON JUL 22 2013 FORECAST UPDATED FOR THE SEVERE THUNDERSTORM WATCH WHICH COVERS MUCH OF THE FORECAST AREA. WILL DEAL WITH THE FOX CITIES AND LAKESHORE REGION AROUND MID EVENING IF NEEDED. && .SHORT TERM...TONIGHT AND TUESDAY ISSUED AT 220 PM CDT MON JUL 22 2013 LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A STRONG COLD FRONT MOVING SOUTHEAST OVER WESTERN LAKE SUPERIOR...WESTERN WISCONSIN TO NORTHWEST IOWA. THOUGH UPPER SUPPORT IS LARGELY NORTH OF LAKE SUPERIOR. THERE MAY BE A WEAK IMPULSE OVER NORTHWEST WISCONSIN THAT HELPED CONVECTION FIRE EARLIER THIS AFTERNOON. THOUGH NOT THE 2500 ML CAPES THAT WERE EXPECTED EARLIER...ML CAPES HAVE RISEN INTO THE 1500-2000 J/KG RANGE WHICH WILL BE MORE THAN SUFFICIENT FOR SEVERE STORMS INTO NORTH-CENTRAL WISCONSIN LATER THIS AFTERNOON...PROVIDED THAT THIS PESKY INHIBITION CAN GET WHITTLED AWAY. DESPITE 0-6KM SHEAR OF 35 KTS AND DECENT LOW LEVEL SHEAR...THE FRONT IS STRUGGLING TO PRODUCE GOOD THUNDERSTORMS EVEN WITH DEWPOINTS IN THE UPPER 60S AHEAD OF IT. BUT POTENTIAL WILL REMAIN FOR SEVERE STORMS TO DEVELOP AS INHIBITION IS FURTHER ERODED. STORMS SHOULD BE ARRIVING INTO N-C WISCONSIN BY 21Z AND IRON MOUNTAIN TO WAUSAU BY 00Z. SEVERE WEATHER IS THE MAIN FORECAST CONCERN. TONIGHT...THE COLD FRONT WILL DRIVE SOUTHEAST ACROSS ALL BUT FAR NORTH-CENTRAL WISCONSIN THIS EVENING...AND EXIT AROUND MIDNIGHT OR SHORTLY THEREAFTER. ASSUMING SEVERE STORMS DEVELOP...STORMS SHOULD BE SURFACE BASED INTO THE EVENING WITH ML CAPES AROUND 1.5-2K J/KG AND 0-6KM BULK SHEAR VALUES AROUND 30-35KTS. STORMS SHOULD GROW MORE ELEVATED WITH TIME THIS EVENING WITH CAPES FALLING AS A RESULT. DECENT 0-1KM HELICITY SHOULD BE ABLE TO SUPPORT ROTATING UPDRAFTS THAT WILL KEEP A FEW STORMS ON THE STRONGER SIDE THOUGH...SO THE SEVERE THREAT SHOULD CONTINUE INTO THE MID-EVENING HOURS. AS STORM INTENSITY GRADUALLY DIMINISHES...THE MAIN THREATS WILL TRANSITION TO A DAMAGING WIND THREAT...WHICH SHOULD REACH INTO THE EASTERN SECTIONS OF THE FORECAST AREA LATE IN THE EVENING. BEHIND THE FRONT...PLENTY OF STRATO-CU UPSTREAM OVER MINNESOTA WILL ARRIVE LATE TONIGHT. WILL KEEP PARTLY TO MOSTLY CLOUDY CONDITIONS GOING THROUGH LATE TONIGHT BEFORE MOISTURE THINS OUT. TUESDAY...DRIER AIR WILL BE FILTERING SOUTH ACROSS MUCH OF CENTRAL AND NORTHEAST WISCONSIN DURING THE MORNING...THOUGH LINGERING MOISTURE OVER THE UPPER PENINSULA AND FAR NORTHERN WISCONSIN MAY KEEP SCT-BKN STRATO-CU AROUND A LITTLE LONGER THAN FURTHER SOUTH. NORTHERLY WINDS WILL BE DRIVING IN A COOLER AND LESS HUMID AIRMASS. HIGH TEMPS WILL ONLY REACH FROM THE UPPER 60S TO MID 70S UNDER MOSTLY SUNNY TO PARTLY CLOUDY SKIES. .LONG TERM...TUESDAY NIGHT THROUGH MONDAY ISSUED AT 220 PM CDT MON JUL 22 2013 UPPER PATTERN DURING PERIOD CHARACTERIZED BY NW UPPER FLOW AND OCNL SHORTWAVE TROFS MOVING THROUGH MEAN TROF POSITION. EACH SHORTWAVE TROF--MID WEEK AND END OF THE WEEK--WILL BRING SCATTERED CONVECTION AND COOLER AIR. STRONGEST OF THE SYSTEMS NEXT WEEKEND WILL BRING CHILLY AIR INTO STATE ON SATURDAY. WHILE UPPER FLOW IS CYCLONIC...SURFACE ANTICYCLONE AND DRY LOW-LEVELS SHOULD MINIMIZE THREAT FOR WIDESPREAD INSTABILITY SHOWERS. TEMP FORECAST THROUGH THE PERIOD GENERALLY A BLEND OF PREVIOUS FORECAST AND BEST PERFORMING 22/12Z MODELS. MIN TEMPS WED AM COULD SLIP TO 40 F IN THE BOGS OF NORTH-CENTRAL WISC. && .AVIATION...FOR 18Z TAF ISSUANCE ISSUED AT 1237 PM CDT MON JUL 22 2013 A STRONG COLD FRONT WILL BRING A SCT TO BKN LINE OF THUNDERSTORMS ACROSS NORTH-CENTRAL WISCONSIN MID TO LATE AFTERNOON...AND NORTHEAST WISCONSIN EARLY TO MID EVENING. STRONG GUSTY WINDS AND LARGE HAIL ARE POSSIBLE WITH THESE STORMS...BUT THAT WILL BE MORE OF A THREAT OVER NORTH-CENTRAL WISCONSIN THAN FURTHER EAST. BEHIND THE FRONT...PLENTY OF MVFR CIGS OVER NORTH DAKOTA AND MINNESOTA...AND WILL BRING THEM INTO CENTRAL AND NORTH-CENTRAL WISCONSIN TONIGHT. DRIER AIR WILL EVENTUALLY ARRIVE LATE TONIGHT TO SCOUR OUT THE MVFR CIGS...WHICH WILL LEAVE GOOD FLYING WEATHER FOR TUESDAY. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE.........TDH SHORT TERM.....MPC LONG TERM......JKL AVIATION.......MPC
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
325 PM CDT MON JUL 22 2013 .VERY SHORT TERM...LATE THIS AFTERNOON...TONIGHT AND TUESDAY...FORECAST CONFIDENCE IS MEDIUM. MAIN FORECAST ISSUE CONTINUES TO BE AREAL COVERAGE OF STORMS AND SEVERE RISK WITH PASSAGE OF COLD FRONT LATE THIS AFTERNOON AND THIS EVENING. LATEST RUNS OF THE HRRR AND WRF 4KM WITH LAPS HIGH RESOLUTION MODELS SHOW CONVECTION ASSOCIATED WITH THE FRONT MOVING SOUTHEAST INTO THE NORTHWEST PORTIONS OF THE FORECAST AREA BY 00Z TUESDAY...THEN FALLING APART AS THEY SHIFT FURTHER SOUTHEAST...EXITING THE FAR SOUTHEAST COUNTIES BY 05Z TUESDAY. NAM/GFS/ECMWF/CANADIAN MODELS ALL SHOW QPF WITH THE FRONTAL PASSAGE THIS EVENING...THOUGH 18Z NAM CONTINUES TO BE SOMEWHAT SLOWER THAN THE OTHER MODELS WITH ITS PROGRESSION. SOME QUESTION WITH THE AREAL COVERAGE OF STORMS...AS UPWARD VERTICAL MOTION WITH FRONT OVER THE AREA IS MODEST COMPARED TO THE NORTHEAST AND SOUTHWEST. STILL...ENOUGH UPWARD MOTION WITH FRONT AND PASSING MODEST 500MB VORTICITY MAXIMUM TO BRING SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS THROUGH THE AREA THIS EVENING...ENDING SOON AFTER MIDNIGHT. MEAN LAYER CAPES OF 1500 TO 2500 J/KG WITH 20 TO 25 KNOTS OF DEEP LAYER SHEAR WILL BRING A RISK FOR LARGE HAIL AND DAMAGING WINDS WITH MAINLY MULTICELL TYPE STRUCTURES. BEST CHANCES WILL REMAIN IN THE SLIGHT RISK AREA FROM SPC...MAINLY NORTHWEST OF A FOND DU LAC TO MADISON TO DARLINGTON LINE. THIS IS WHERE THE SOMEWHAT BETTER DEEP LAYER SHEAR WILL BE LOCATED. LOCALLY HEAVY RAINFALL IS ALSO POSSIBLE WITH DECENT PRECIPITABLE WATER VALUES. BRISK NORTH WINDS WITH COLD AIR ADVECTION BEHIND FRONTAL PASSAGE LATER TONIGHT INTO TUESDAY WILL BRING A COOLER AND DRIER AIRMASS INTO THE REGION. THIS IS IN ADVANCE OF HIGH PRESSURE MOVING TOWARD THE REGION FROM THE NORTHWEST. QUIET WEATHER WITH PARTLY CLOUDY SKIES ARE EXPECTED. BREEZY NORTH WINDS WILL KEEP TEMPERATURES SOMEWHAT BELOW SEASONAL NORMALS...ESPECIALLY NEAR THE LAKE. TUESDAY NIGHT THROUGH THURSDAY...FORECAST CONFIDENCE MEDIUM TO HIGH NW FLOW ALOFT WILL PREVAIL WITH HIGH PRESSURE CENTERED OVER WI FOR TUE NT AND WED. A WEAK SHORTWAVE TROUGH MAY BRING SCT-BKN MID LEVEL CLOUDS FOR A TIME WED AFTERNOON AND EVENING. AT MOST...A FEW SPRINKLES TOWARD CENTRAL WI. THE HIGH THEN SHIFTS INTO THE ERN GREAT LAKES FOR WED NT AND THU WHILE A SFC TROUGH MOVES INTO NW WI ON THU. THIS IS AHEAD OF A LARGE UPPER TROUGH THAT IS DIGGING SEWD INTO SRN MANITOBA AND ONTARIO CANADA. WEAK LOW LEVEL WARM ADVECTION WILL DEVELOP LATE WED NT AND THU. 925 MB TEMPS YIELD SFC TEMPS IN THE MID 70S ON WED AND UPPER 70S TO 80F FOR THU. .LONG TERM... FRIDAY THROUGH MONDAY...FORECAST CONFIDENCE MEDIUM THE LARGE POLAR TROUGH WILL TRACK ALONG THE NRN GRTLKS AND CANADIAN BORDER FOR THE WEEKEND. ITS COLD FRONT WILL BRING CHANCES OF SHOWERS AND TSTORMS FOR FRI AND SAT. VERY PLEASANT AND DRY SUMMER WX TO PREVAIL AFTERWARD. && .AVIATION/00Z TAFS/...VFR CONDITIONS ARE EXPECTED THROUGH LATE THIS AFTERNOON ACROSS TAF SITES. SOME DIURNAL CUMULUS CLOUDS WILL LINGER DURING THIS TIME. LAKE BREEZE WILL SHIFT WINDS TO THE SOUTHEAST AT MILWAUKEE AND KENOSHA BY 21Z TO 22Z MONDAY. MADISON SHOULD SEE LIGHT SOUTHWEST WINDS. COLD FRONT WILL SLIDE SOUTHEAST THROUGH TAF SITES BETWEEN 02Z AND 06Z TUESDAY. SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ARE EXPECTED WITH THE FRONT. A FEW MAY CONTAIN LARGE HAIL AND GUSTY WINDS...WITH BETTER CHANCE AT MADISON...LOWER CONFIDENCE AT THE EASTERN SITES. MVFR/IFR VISIBILITIES ARE POSSIBLE WITH ANY STORMS. VFR CONDITIONS ARE THEN EXPECTED AFTER FRONTAL PASSAGE INTO TUESDAY. WINDS WILL SHIFT NORTH NORTHWEST AFTER THE FRONTAL PASSAGE...AND BECOME NORTH NORTHEAST THROUGH TUESDAY. WINDS WILL BECOME GUSTY WITH COOLER AND DRIER AIR MOVING INTO THE REGION DURING THIS TIME. GUSTS INTO THE 20 TO 25 KNOT RANGE ARE POSSIBLE. $$ .MARINE...A TIGHT PRESSURE GRADIENT WILL DEVELOP LATE TONIGHT INTO TUESDAY...AFTER THE COLD FRONTAL PASSAGE. THIS WILL RESULT IN BREEZY NORTH TO NORTHEAST WINDS ACROSS THE NEARSHORE WATERS. FREQUENT GUSTS TO 25 KNOTS ARE POSSIBLE LATE TONIGHT INTO TUESDAY NIGHT. THIS SHOULD CAUSE WAVES TO BECOME HIGH...WITH ONSHORE FLOW AT TIMES. THE WAVES SHOULD REMAIN HIGH INTO WEDNESDAY BEFORE SUBSIDING WITH WEAKER WINDS. THUS...A SMALL CRAFT ADVISORY HAS BEEN ISSUED FOR LATE TONIGHT INTO WEDNESDAY. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...NONE. LM...SMALL CRAFT ADVISORY FROM 4 AM TUESDAY TO 4 PM CDT WEDNESDAY FOR LMZ643>646. && $$ TONIGHT/TUESDAY AND AVIATION/MARINE...WOOD TUESDAY NIGHT THROUGH MONDAY...GEHRING
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE

.SHORT TERM...TONIGHT AND TUESDAY ISSUED AT 220 PM CDT MON JUL 22 2013 LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A STRONG COLD FRONT MOVING SOUTHEAST OVER WESTERN LAKE SUPERIOR...WESTERN WISCONSIN TO NORTHWEST IOWA. THOUGH UPPER SUPPORT IS LARGELY NORTH OF LAKE SUPERIOR. THERE MAY BE A WEAK IMPULSE OVER NORTHWEST WISCONSIN THAT HELPED CONVECTION FIRE EARLIER THIS AFTERNOON. THOUGH NOT THE 2500 ML CAPES THAT WERE EXPECTED EARLIER...ML CAPES HAVE RISEN INTO THE 1500-2000 J/KG RANGE WHICH WILL BE MORE THAN SUFFICIENT FOR SEVERE STORMS INTO NORTH-CENTRAL WISCONSIN LATER THIS AFTERNOON...PROVIDED THAT THIS PESKY INHIBITION CAN GET WHITTLED AWAY. DESPITE 0-6KM SHEAR OF 35 KTS AND DECENT LOW LEVEL SHEAR...THE FRONT IS STRUGGLING TO PRODUCE GOOD THUNDERSTORMS EVEN WITH DEWPOINTS IN THE UPPER 60S AHEAD OF IT. BUT POTENTIAL WILL REMAIN FOR SEVERE STORMS TO DEVELOP AS INHIBITION IS FURTHER ERODED. STORMS SHOULD BE ARRIVING INTO N-C WISCONSIN BY 21Z AND IRON MOUNTAIN TO WAUSAU BY 00Z. SEVERE WEATHER IS THE MAIN FORECAST CONCERN. TONIGHT...THE COLD FRONT WILL DRIVE SOUTHEAST ACROSS ALL BUT FAR NORTH-CENTRAL WISCONSIN THIS EVENING...AND EXIT AROUND MIDNIGHT OR SHORTLY THEREAFTER. ASSUMING SEVERE STORMS DEVELOP...STORMS SHOULD BE SURFACE BASED INTO THE EVENING WITH ML CAPES AROUND 1.5-2K J/KG AND 0-6KM BULK SHEAR VALUES AROUND 30-35KTS. STORMS SHOULD GROW MORE ELEVATED WITH TIME THIS EVENING WITH CAPES FALLING AS A RESULT. DECENT 0-1KM HELICITY SHOULD BE ABLE TO SUPPORT ROTATING UPDRAFTS THAT WILL KEEP A FEW STORMS ON THE STRONGER SIDE THOUGH...SO THE SEVERE THREAT SHOULD CONTINUE INTO THE MID-EVENING HOURS. AS STORM INTENSITY GRADUALLY DIMINISHES...THE MAIN THREATS WILL TRANSITION TO A DAMAGING WIND THREAT...WHICH SHOULD REACH INTO THE EASTERN SECTIONS OF THE FORECAST AREA LATE IN THE EVENING. BEHIND THE FRONT...PLENTY OF STRATO-CU UPSTREAM OVER MINNESOTA WILL ARRIVE LATE TONIGHT. WILL KEEP PARTLY TO MOSTLY CLOUDY CONDITIONS GOING THROUGH LATE TONIGHT BEFORE MOISTURE THINS OUT. TUESDAY...DRIER AIR WILL BE FILTERING SOUTH ACROSS MUCH OF CENTRAL AND NORTHEAST WISCONSIN DURING THE MORNING...THOUGH LINGERING MOISTURE OVER THE UPPER PENINSULA AND FAR NORTHERN WISCONSIN MAY KEEP SCT-BKN STRATO-CU AROUND A LITTLE LONGER THAN FURTHER SOUTH. NORTHERLY WINDS WILL BE DRIVING IN A COOLER AND LESS HUMID AIRMASS. HIGH TEMPS WILL ONLY REACH FROM THE UPPER 60S TO MID 70S UNDER MOSTLY SUNNY TO PARTLY CLOUDY SKIES. .LONG TERM...TUESDAY NIGHT THROUGH MONDAY ISSUED AT 220 PM CDT MON JUL 22 2013 UPPER PATTERN DURING PERIOD CHARACTERIZED BY NW UPPER FLOW AND OCNL SHORTWAVE TROFS MOVING THROUGH MEAN TROF POSITION. EACH SHORTWAVE TROF--MID WEEK AND END OF THE WEEK--WILL BRING SCATTERED CONVECTION AND COOLER AIR. STRONGEST OF THE SYSTEMS NEXT WEEKEND WILL BRING CHILLY AIR INTO STATE ON SATURDAY. WHILE UPPER FLOW IS CYCLONIC...SURFACE ANTICYCLONE AND DRY LOW-LEVELS SHOULD MINIMIZE THREAT FOR WIDESPREAD INSTABILITY SHOWERS. TEMP FORECAST THROUGH THE PERIOD GENERALLY A BLEND OF PREVIOUS FORECAST AND BEST PERFORMING 22/12Z MODELS. MIN TEMPS WED AM COULD SLIP TO 40 F IN THE BOGS OF NORTH-CENTRAL WISC. && .AVIATION...FOR 18Z TAF ISSUANCE ISSUED AT 1237 PM CDT MON JUL 22 2013 A STRONG COLD FRONT WILL BRING A SCT TO BKN LINE OF THUNDERSTORMS ACROSS NORTH-CENTRAL WISCONSIN MID TO LATE AFTERNOON...AND NORTHEAST WISCONSIN EARLY TO MID EVENING. STRONG GUSTY WINDS AND LARGE HAIL ARE POSSIBLE WITH THESE STORMS...BUT THAT WILL BE MORE OF A THREAT OVER NORTH-CENTRAL WISCONSIN THAN FURTHER EAST. BEHIND THE FRONT...PLENTY OF MVFR CIGS OVER NORTH DAKOTA AND MINNESOTA...AND WILL BRING THEM INTO CENTRAL AND NORTH-CENTRAL WISCONSIN TONIGHT. DRIER AIR WILL EVENTUALLY ARRIVE LATE TONIGHT TO SCOUR OUT THE MVFR CIGS...WHICH WILL LEAVE GOOD FLYING WEATHER FOR TUESDAY. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....MPC LONG TERM......JKL AVIATION.......MPC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1232 PM CDT MON JUL 22 2013 .MESOSCALE DISCUSSION... ISSUED AT 1120 AM CDT MON JUL 22 2013 STILL ASSESSING SEVERE WEATHER POSSIBILITIES FOR LATER TODAY. SHORT WAVE TROUGH CONTINUES TO MOVE THROUGH ONTARIO...NORTH OF INTERNATIONAL BORDER. ASSOCIATED TRAILING COLD FRONT EXTENDS FROM CENTRAL MINNESOTA INTO SIOUX FALLS AREA AS OF 16Z WITH WEAKENING STORM COMPLEX ALONG MISSOURI RIVER. MORNING STRATUS AND FOG ALSO THINING ACROSS THE AREA. DEEP SHEAR IS MUCH MORE FAVORABLE ACROSS NORTHERN WISCONSIN WHILE LOWER LEVEL SHEAR IS HIGHER AS YOU MOVE FURTHER SOUTH-SOUTHWEST. 0-1KM SHEAR IS ALSO STRONGER TO THE NORTH BUT DOES EXTENDED AHEAD AND ALONG THE APPROACHING COLD FRONT. MORNING CLOUD SHIELDS KEEPING HEATING DOWN A BIT BUT DEW POINTS ARE CLIMBING AHEAD OF FRONT SO EXPECT MOST UNSTABLE CAPE VALUES INTO THE 2000 J/KG RANGE BY MID AFTERNOON. LATEST SEVERAL HRRR MESOSCALE MODEL RUNS STILL SUGGEST DEVELOPMENT IN 19-20Z TIME FRAME. ARW/NMM MESOSCALE MODELS ALSO HINT AT THIS BUT SOME UNCERTAINTY ON EXTENT OF COVERAGE AREA. THERE ARE HINTS SUPERCELLS COULD INITIALLY FORM OVER NORTHERN WISCONSIN WITH ONE COMPLEX FORMING WHILE OTHER STORMS FORM ALONG FRONT TO THE SOUTH. MOISTURE TRANSPORT ALSO SHIFTS EAST QUICKLY THROUGH DAY SO THINKING WE WOULD HAVE A NARROW WINDOW OF STORM POSSIBILITIES THAT COULD EVEN SPLIT PARTS OF THE AREA. THIS COULD OCCUR AS SOUTHERN STORMS DIVE INTO HIGHER CAPE VALUES CLOSER AND SOUTH OF I-80. SHEAR VALUES SUGGEST ANY TORNADO RISK REMAINS HIGHEST IN NORTH CENTRAL WISCONSIN WITH INITIAL SUPERCELLS...SOME OF WHICH COULD ALSO PRODUCE HAIL IF CELLS CAN MATERIALIZE CAPE AND GROW THAT STRONG. THIS AREA WOULD LIKELY FORM A MORE LINEAR STRUCTURE BY EARLY EVENING. OTHER STORMS THAT FORM TO THE SOUTH WILL LIKELY BE MORE MULTI-CELLULAR IN NATURE WITH MAINLY WIND THREATS. SO OVERALL CONFIDENCE IS MODEST BUT WITH PROGRESSIVE STORMS...TIME WINDOW LOOKS MORE CERTAIN...FROM 19Z TO 01Z. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 335 AM CDT MON JUL 22 2013 MAIN FORECAST CONCERNS ARE ON THE POTENTIAL FOR SEVERE THUNDERSTORMS THIS AFTERNOON INTO EARLY THIS EVENING. LATEST WATER VAPOR IMAGERY SHOWED A TROUGH EXTENDING FROM SOUTHERN MANITOBA SOUTH THROUGH THE EASTERN DAKOTAS AND MOVING EAST. SURFACE OBSERVATIONS SHOWED LOW PRESSURE OVER FAR SOUTHEAST MANITOBA...ALONG THE NORTH DAKOTA/MANITOBA BORDER. A COLD FRONT EXTENDED FROM EASTERN NORTH DAKOTA SOUTH THROUGH NORTH CENTRAL SOUTH DAKOTA AND WAS MOVING SOUTHEAST. THE COLD FRONT WILL BE THE FOCUS FOR THUNDERSTORM DEVELOPMENT LATE THIS MORNING INTO THIS AFTERNOON. THE COLD FRONT WILL CONTINUE ITS SOUTHEAST MOVEMENT THIS MORNING AND BY LATE MORNING IS EXPECTED TO EXTEND FROM THE ARROWHEAD OF MINNESOTA SOUTH TO ALONG THE INTERSTATE 35 CORRIDOR. THE FRONT LOOKS TO PUSH INTO SOUTHEAST MINNESOTA AND NORTHEAST IOWA EARLY THIS AFTERNOON THEN MARCH EAST ACROSS THE FORECAST AREA THROUGH THE AFTERNOON HOURS. THE NAM AND GFS MLCAPE VALUES CLIMB INTO THE 1500 TO 2500 J/KG RANGE AHEAD OF THE FRONT. RUC FORECAST SOUNDINGS SHOW SURFACE BASED CAPE VALUES CLIMBING TO AROUND 3000 J/KG. 0-6 KM BULK SHEAR ISN/T OVERLY IMPRESSIVE...HOVERING AROUND 30 KTS. MOST OF THIS SHEAR IS LOCATED IN THE 0-3 KM LAYER AND ORIENTED PERPENDICULAR TO THE FRONT...SUGGESTING A LINEAR MODE TO THE CONVECTION WITH THE POTENTIAL FOR DAMAGING WINDS. THE 0-1 KM SHEAR ALSO RAMPS UP THIS AFTERNOON...INCREASING TO AROUND 22 KTS. CONVERGENCE ALONG THE FRONT IS ALSO NOT OVERLY IMPRESSIVE THIS AFTERNOON BUT GIVEN THE INSTABILITY IN PLACE...IT WILL NOT TAKE MUCH TO GET THUNDERSTORMS TO DEVELOP. FORECAST MODELS HAVE BEEN CONSISTENT SHOWING WARMER AIR ALOFT...CENTERED AROUND 800 MB...THAT WILL HAVE TO BE OVERCOME TO GET THUNDERSTORMS TO DEVELOP. THERE APPEARS THAT THERE WILL BE ENOUGH HEATING THIS AFTERNOON AT THE SURFACE AND SLIGHT COOLING ALOFT TO WEAKEN THE CAP. FORECAST SOUNDINGS REALLY WEAKEN THE CAP BY MID AFTERNOON. ALSO...GIVEN THE INCREASING 0-1 KM SHEAR THIS AFTERNOON WILL HAVE TO KEEP AN EYE ON THE POTENTIAL FOR AN ISOLATED TORNADO...ESPECIALLY ALONG AND NORTH OF INTERSTATE 94. SURFACE WINDS TURN TO THE SOUTHWEST JUST AHEAD OF THE FRONT...SO THINKING OVERALL TORNADO THREAT APPEARS LOW AT THIS TIME. CANNOT RULE OUT SOME SEVERE HAIL THIS AFTERNOON GIVEN THE STRONG CAPE IN THE HAIL GROWTH ZONE. THINKING THE PRIMARY SEVERE THREAT TODAY SHOULD BE DAMAGING WINDS. THE 22.06 HRRR SHOWS STORMS ERUPTING ALONG THE COLD FRONT IN THE 19 TO 21Z TIMEFRAME ACROSS WEST CENTRAL WISCONSIN INTO SOUTHEAST MINNESOTA. THE 22.00 HIRES ARW ALSO SHOWS CONVECTION ERUPTING ACROSS THESE AREAS BUT LATER...IN THE 21 TO 00Z TIMEFRAME. GIVEN THAT THE MAJORITY OF THE MESOSCALE MODELS ARE CONVECTING ALONG THE FRONT...CONFIDENCE IS INCREASING THAT STORMS WILL INDEED DEVELOP THIS AFTERNOON. HIGH TEMPERATURES TODAY WILL CLIMB INTO THE LOWER TO MIDDLE 80S AHEAD OF THE FRONT. DEWPOINTS ARE EXPECTED TO CLIMB INTO THE UPPER 60S TO AROUND 70...MAKING IT FEEL A LITTLE ON THE MUGGY SIDE. THE FRONT WILL EXIT THE FORECAST AREA LATE THIS EVENING INTO THE OVERNIGHT WITH HIGH PRESSURE BUILDING IN ITS WAKE. A STRATUS DECK COULD DEVELOP IN THE WAKE OF THE COLD FRONT LEADING TO MOSTLY CLOUDY SKIES DURING THE OVERNIGHT HOURS. OTHERWISE...SKIES WILL RANGE FROM PARTLY CLOUDY TO MOSTLY CLEAR WITH OVERNIGHT LOWS FALLING INTO THE UPPER 50S TO LOWER 60S. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 335 AM CDT MON JUL 22 2013 SURFACE HIGH PRESSURE WILL BE IN CONTROL ACROSS THE REGION ON TUESDAY PROVIDING DRY CONDITIONS AND MORE SEASONABLE TEMPERATURES. NORTHERLY WINDS WILL USHER IN A MUCH DRIER AIRMASS WITH DEWPOINTS FALLING INT THE LOWER 50S. HIGH TEMPERATURES WILL RANGE FROM THE LOWER 70S OVER NORTHERN WISCONSIN TO THE THE UPPER 70S TO AROUND 80 ACROSS NORTHEAST IOWA. THE HIGH WILL BE POSITIONED DIRECTLY OVER THE FORECAST AREA TUESDAY NIGHT LEADING TO CALM WINDS AND CLEAR SKIES. THIS WILL SET THE STAGE FOR FOG DEVELOPMENT...ESPECIALLY IN VALLEY LOCATIONS AND OVER THE CENTRAL WISCONSIN CRANBERRY COUNTRY. OVERNIGHT LOWS TUESDAY NIGHT WILL FALL INTO THE 50S...WITH LOW LYING AREAS SUCH AS SPARTA AND BLACK RIVER FALLS FALLING INTO THE UPPER 40S. THE HIGH SLIDES EAST OF THE REGION ON WEDNESDAY. A SHORTWAVE TROUGH MOVES INTO THE REGION LATE WEDNESDAY NIGHT INTO THURSDAY...IN NORTHWEST FLOW ALOFT...BRINGING CHANCES FOR SHOWERS AND THUNDERSTORMS TO THE AREA. A COLD FRONT THEN PUSHES ACROSS THE UPPER MISSISSIPPI RIVER VALLEY LATE THURSDAY INTO FRIDAY AS A TROUGH DIGS SOUTHWARD OUT OF ONTARIO. AN UNSEASONABLY COOL AIRMASS MOVES INTO THE REGION IN THE WAKE OF THE FRONT FOR FRIDAY INTO THE WEEKEND. 850 MB TEMPERATURE STANDARDIZED ANOMALIES FALL TO NEGATIVE 2.5 SATURDAY INTO SUNDAY. PLAN ON HIGH TEMPERATURES IN THE LOWER 70S OVER THE WEEKEND. WEAK SHORTWAVES MAY BRING SCATTERED SHOWERS AND THUNDERSTORMS TO THE AREA ON SATURDAY..WITH CHANCES SHIFTING SOUTH OF INTERSTATE 90 DURING THE DAY ON SUNDAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1232 PM CDT MON JUL 22 2013 APPROACHING COLD FRONT WILL LIKELY BRING WINDOW OF CONVECTION THAT COULD BRING TEMPORARY MVFR CONDITIONS UNTIL PASSAGE EARLY THIS EVENING. NORMAL VEERING WIND SHIFT EXPECTED WITH FRONT AS WELL. QUESTIONS TO WHAT DEGREE STRATUS FIELD IN BROAD COLD AIR ADVECTION BEHIND FRONT WILL HOLD TOGETHER AND IMPACT AVIATION TONIGHT. VERY CELLULAR NATURE TO CLOUDS SUGGEST MORE DIURNAL BUT FEEL THERE WILL LIKELY BE A WINDOW OF LOWER CEILINGS BEFORE IT DISSIPATES. COULD SEE SOME REFORM LATER TUESDAY AS WELL IN COLDER AIR ALOFT. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ MESOSCALE....SHEA SHORT TERM...WETENKAMP LONG TERM....WETENKAMP AVIATION.....SHEA
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1220 PM CDT MON JUL 22 2013 .UPDATE...MAIN FORECAST ISSUE WILL BE AREAL COVERAGE OF STORMS AND SEVERE RISK WITH PASSAGE OF COLD FRONT LATE THIS AFTERNOON AND THIS EVENING. 12Z NAM SLOWER THAN 12Z GFS WITH FRONTAL PASSAGE THROUGH THE AREA THIS EVENING. HRRR AND WRF 4KM WITH LAPS HIGH RESOLUTION MODELS SHOW CONVECTION ASSOCIATED WITH THE FRONT MOVING SOUTHEAST THROUGH THE FORECAST AREA BETWEEN MAINLY 23Z TODAY AND 05Z TUESDAY. THEY DIFFER WITH TRENDS DURING THIS TIME...WITH THE HRRR FAVORING MORE OF THE SOUTHWEST HALF OF THE AREA...AND THE WRF 4KM WITH LAPS FAVORING CONVECTION FROM IOWA MERGING WITH FRONTAL CONVECTION. SOME QUESTION WITH THE AMOUNT OF AREAL COVERAGE OF STORMS...AS UPWARD VERTICAL MOTION WITH FRONT OVER THE AREA IS MODEST COMPARED TO THE NORTHEAST AND SOUTHWEST. STILL...ENOUGH UPWARD MOTION WITH FRONT AND PASSING MODEST 500MB VORTICITY MAXIMUM TO BRING SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS THROUGH THE AREA. WILL UPDATE FORECAST TO TREND IN THIS MANNER. MEAN LAYER CAPES OF 1500 TO 2500 J/KG WITH 20 TO 25 KNOTS OF DEEP LAYER SHEAR WILL BRING RISK FOR LARGE HAIL AND DAMAGING WINDS. BEST CHANCES WILL BE IN SLIGHT RISK AREA FROM SPC...MAINLY IN THE SOUTH CENTRAL WISCONSIN COUNTIES. THIS IS WHERE THE BETTER DEEP LAYER SHEAR WILL BE LOCATED. LOCALLY HEAVY RAINFALL IS ALSO POSSIBLE WITH DECENT PRECIPITABLE WATER VALUES. SHOWERS AND STORMS SHOULD DIMINISH QUICKLY AFTER FRONTAL PASSAGE. && .AVIATION/18Z TAFS/...VFR CONDITIONS ARE EXPECTED THROUGH THIS AFTERNOON ACROSS TAF SITES. DIURNAL CUMULUS CLOUDS WILL LINGER DURING THIS TIME...AND MAY BE MVFR LEVEL AT TIMES EARLY THIS AFTERNOON. LAKE BREEZE WILL SHIFT WINDS TO THE SOUTHEAST AT MILWAUKEE BY 18Z MONDAY...AND KENOSHA BY 21Z MONDAY. IT MAY REACH WAUKESHA BUT LEFT OUT OF TAF THERE DUE TO UNCERTAINTY. MADISON SHOULD SEE LIGHT SOUTHWEST WINDS. COLD FRONT WILL SLIDE SOUTHEAST THROUGH TAF SITES BETWEEN 01Z AND 05Z TUESDAY. SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ARE EXPECTED WITH THE FRONT...SOME OF WHICH MAY CONTAIN LARGE HAIL AND GUSTY WINDS. BEST SHOT WILL BE AT MADISON...LOWER CONFIDENCE AT THE EASTERN SITES. MVFR/IFR VISIBILITIES ARE POSSIBLE WITH ANY STORMS. VFR CONDITIONS ARE THEN EXPECTED AFTER FRONTAL PASSAGE INTO TUESDAY. WINDS WILL SHIFT NORTH NORTHWEST AFTER THE FRONTAL PASSAGE...AND BECOME NORTH NORTHEAST THROUGH TUESDAY. WINDS WILL BECOME GUSTY WITH COOLER AND DRIER AIR MOVING INTO THE REGION DURING THIS TIME. GUSTS INTO THE 20 TO 25 KNOT RANGE ARE POSSIBLE. && .MARINE...A TIGHT PRESSURE GRADIENT WILL DEVELOP LATE TONIGHT INTO TUESDAY...AFTER THE COLD FRONTAL PASSAGE. THIS WILL RESULT IN BREEZY NORTH TO NORTHEAST WINDS ACROSS THE NEARSHORE WATERS. FREQUENT GUSTS TO 25 KNOTS ARE POSSIBLE LATE TONIGHT INTO TUESDAY NIGHT. THIS SHOULD CAUSE WAVES TO BECOME HIGH...WITH ONSHORE FLOW AT TIMES. THE WAVES MAY REMAIN HIGH INTO WEDNESDAY BEFORE SUBSIDING WITH WEAKER WINDS. THUS...A SMALL CRAFT ADVISORY MAY BE NEEDED FOR LATE TONIGHT INTO WEDNESDAY. && .PREV DISCUSSION... /ISSUED 347 AM CDT MON JUL 22 2013/ SHORT TERM... TODAY AND TONIGHT. FORECAST CONFIDENCE LOW TO MEDIUM. SHORT WAVE TROUGH NEAR LAKE WINNIPEG ON WATER VAPOR LOOPS IS DRIVING ASSOCIATED SURFACE LOW ALONG U.S./CANADIAN BORDER. THUNDERSTORM COMPLEX MOVING INTO NW MN FROM ERN N DAKOTA ALONG TRAILING SURFACE TROUGH IN RELATIVELY WEAK WARM AIR ADVECTION REGIME AHEAD OF THIS WAVE...WITH SWLY 850 MB WINDS OF 15 TO 25 KTS. MOIST SLY SURFACE FLOW AHEAD OF THIS TROUGH POOLING ALONG TROUGH WITH MID-UPPER 60 DEW POINTS. THERMAL RIDGE PUSHES INTO CWA THIS AFTERNOON WITH 850 TEMPS OF 16 TO 18C AND 925 MB TEMPERATURES OF 24C TO 25C...LEADING TO MID-UPPER 80S HIGHS AND A RETURN TO MUGGY CONDITIONS. BEST CHANCES FOR THUNDERSTORMS APPEAR TO BE ACROSS CENTRAL/NORTHERN WISCONSIN CLOSER TO THE SHORT WAVE TROUGH. BEST HEIGHT FALLS STAY WELL NORTH OF THE CWA THROUGH THE DAY...WITH SOME WEAK FALLS DIPPING INTO SRN WI BETWEEN 06Z AND 12Z TUESDAY AS TROUGH DEEPENS OVER EASTERN ONTARIO. 00Z GFS AND ECMWF SHOW HIGHER MID-LEVEL RH AND BETTER OMEGA AS WELL AS 850 MB TEMP ADVECTION STAY NORTH OF CWA. HI-RES MODELS SHOW CONVECTION DEVELOPING ALONG FRONT TO THE NW OF FORECAST AREA DURING PEAK MID-AFTERNOON HEATING. DECENT INSTABILITY OVER ALL OF THE AREA THIS AFTERNOON AND EVENING...WITH SHOWALTER INDICES BETWEEN -2 AND -3C AND SURFACE-BASED CAPE BETWEEN 1500 AND 2000 J/KG BUT BETTER 0-6KM BULK SHEAR IS TO THE NORTH...JUST BRUSHING NWRN CWA WHERE SPC HAS DAY 1 SLIGHT RISK OF SEVERE WITH MAIN THREATS HAIL AND DAMAGING WIND GUSTS. AFTER DRYING OUT A BIT BEHIND YESTERDAY CONVECTION...PWS INCREASE TO 1.5 TO 1.6 INCH...SO POTENTIAL IS CERTAINLY THERE FOR MORE HEAVY RAIN WITH STORMS. WILL TIME PRECIPITATION CHANCES IN WITH MOISTURE CONVERGENCE AND FRONTOGENETIC FORCING AHEAD OF THE FRONT...COVERING THE NW 1/2 OF CWA BY 00Z...AND THE REMAINDER OF THE FORECAST AREA IN THE EARLY EVENING. WILL LIMIT LIKELY POPS TO THE NORTH FOR NOW. NAM SLOWER THAN GFS OR ECMWF WITH 850 MB TROUGH AXIS...WITH COOLER AIR JUST MOVING INTO NW CWA BY 12Z TUESDAY WHILE OTHERS HAVE 850 MB BAROCLINIC ZONE DOWN TO THE WI/IL BORDER BY 12Z. WILL KEEP CHANCE/ SLIGHT CHANCE POPS GOING AFTER 06Z...BUT CLEAR THE NW 1/2 BY 11Z TUESDAY. TUESDAY...FORECAST CONFIDENCE MEDIUM. ANY LINGERING THUNDERSTORMS ALONG THE FRONT SHOULD BE OUT OF SOUTHEAST WI BY 12Z TUE MORNING. DEBATED WHETHER OR NOT TO CARRY ANY POPS INTO 12-15Z TUE...BUT DECIDED NOT TO BASED ON MODELS NOW SHOWING A SLIGHTLY FASTER FRONT. EXPECTING NORTH WINDS TO INCREASE ALONG AND BEHIND THIS COLD FRONT TUESDAY MORNING. HIGHEST WINDS WILL BE NEAR THE LAKE. GUSTS TO 20 MPH WILL BE LIKELY. SKIES ARE EXPECTED TO CLEAR BY TUESDAY AFTERNOON AND SUNSHINE WILL HELP TEMPS TO REBOUND INTO THE UPPER 70S INLAND...AND LOWER/MID 70S NEAR THE SHORELINE. CLEAR SKIES AND RADIATIONAL COOLING WILL LEAD TO LOWS IN THE 50S. NOT EXPECTING FOG SINCE WINDS JUST ABOVE THE GROUND WILL STILL BE IN THE 15-20 KT RANGE. WEDNESDAY AND THURSDAY...FORECAST CONFIDENCE HIGH. SURFACE HIGH PRESSURE WILL SETTLE INTO THE GREAT LAKES REGION WITH WEAK MID AND UPPER LEVEL RIDGING MOVING INTO THE CENTER OF THE COUNTRY. TEMPS WILL BE A LITTLE BELOW NORMAL...WITH HIGHS EXPECTED IN THE UPPER 70S. MODELS ARE MAINTAINING A SMALL THUNDERSTORM CHANCE FOR THU AFTERNOON AND NIGHT...BUT THESE SEEM MINIMAL GIVEN THE DRY AIR IN PLACE OVER SOUTHERN WI AT THIS TIME AND THE VERY WEAK FORCING ASSOCIATED WITH THE MODEL QPF. LONG TERM... FRIDAY THROUGH SUNDAY...FORECAST CONFIDENCE MEDIUM TO LOW. A CLOSED UPPER LOW WILL BE SPINNING OVER ONTARIO OVER THE WEEKEND. A LOBE OF VORTICITY WILL ROTATE DOWN THROUGH WI AT SOME POINT AND BRING A CHANCE OF SHOWERS AND THUNDERSTORMS TO SOUTHERN WI. TIMING IS UNCERTAIN...BUT SOMETIME IN THE SATURDAY AFTERNOON/NIGHT TIME PERIOD LOOKS REASONABLE. UNFORTUNATELY...THERE IS A SMALL CHANCE FOR THUNDER IN EVERY TIME PERIOD IN THE FORECAST FOR THE WEEKEND GIVEN SUBTLE MODEL DIFFERENCES AND VERY WEAK SHORTWAVES ROTATING AROUND THE UPPER LOW THAT COULD SPAWN AN ISOLATED THUNDERSTORM WITH DIURNAL HEATING. CHANCES ARE VERY LOW OUTSIDE OF THE SAT AFTERNOON/NIGHT TIME. TEMPS WILL GENERALLY BE IN THE 70S THROUGH THE WEEKEND. AVIATION/12Z TAFS/...IFR CIGS/VSBYS HAVE MOVED INTO EASTERN TAF SITES AS LIGHT NORTH TO NORTHEAST WINDS HAVE BROUGHT COOLER AIR OFF THE LAKE INTO THE RAIN-MOISTENED AIR MASS OVER THE REGION. EXPECT THE CIGS AND VSBYS TO LIFT BY MID-MORNING AS GRADIENT WINDS COME AROUND TO THE SOUTH...THEN SOUTHWEST AHEAD OF APPROACHING COLD FRONT. VFR THROUGH THE REST OF THE PERIOD...WITH MVFR IN SCATTERED THUNDERSTORMS AROUND/AFTER 00Z AHEAD OF COLD FRONT. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...NONE. LM...NONE. && $$ UPDATE...WOOD TODAY/TONIGHT AND AVIATION/MARINE...REM TUESDAY THROUGH SUNDAY...MRC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1120 AM CDT MON JUL 22 2013 .MESOSCALE DISCUSSION... ISSUED AT 1120 AM CDT MON JUL 22 2013 STILL ASSESSING SEVERE WEATHER POSSIBILITIES FOR LATER TODAY. SHORT WAVE TROUGH CONTINUES TO MOVE THROUGH ONTARIO...NORTH OF INTERNATIONAL BORDER. ASSOCIATED TRAILING COLD FRONT EXTENDS FROM CENTRAL MINNESOTA INTO SIOUX FALLS AREA AS OF 16Z WITH WEAKENING STORM COMPLEX ALONG MISSOURI RIVER. MORNING STRATUS AND FOG ALSO THINING ACROSS THE AREA. DEEP SHEAR IS MUCH MORE FAVORABLE ACROSS NORTHERN WISCONSIN WHILE LOWER LEVEL SHEAR IS HIGHER AS YOU MOVE FURTHER SOUTH-SOUTHWEST. 0-1KM SHEAR IS ALSO STRONGER TO THE NORTH BUT DOES EXTENDED AHEAD AND ALONG THE APPROACHING COLD FRONT. MORNING CLOUD SHIELDS KEEPING HEATING DOWN A BIT BUT DEW POINTS ARE CLIMBING AHEAD OF FRONT SO EXPECT MOST UNSTABLE CAPE VALUES INTO THE 2000 J/KG RANGE BY MID AFTERNOON. LATEST SEVERAL HRRR MESOSCALE MODEL RUNS STILL SUGGEST DEVELOPMENT IN 19-20Z TIME FRAME. ARW/NMM MESOSCALE MODELS ALSO HINT AT THIS BUT SOME UNCERTAINTY ON EXTENT OF COVERAGE AREA. THERE ARE HINTS SUPERCELLS COULD INITIALLY FORM OVER NORTHERN WISCONSIN WITH ONE COMPLEX FORMING WHILE OTHER STORMS FORM ALONG FRONT TO THE SOUTH. MOISTURE TRANSPORT ALSO SHIFTS EAST QUICKLY THROUGH DAY SO THINKING WE WOULD HAVE A NARROW WINDOW OF STORM POSSIBILITIES THAT COULD EVEN SPLIT PARTS OF THE AREA. THIS COULD OCCUR AS SOUTHERN STORMS DIVE INTO HIGHER CAPE VALUES CLOSER AND SOUTH OF I-80. SHEAR VALUES SUGGEST ANY TORNADO RISK REMAINS HIGHEST IN NORTH CENTRAL WISCONSIN WITH INITIAL SUPERCELLS...SOME OF WHICH COULD ALSO PRODUCE HAIL IF CELLS CAN MATERIALIZE CAPE AND GROW THAT STRONG. THIS AREA WOULD LIKELY FORM A MORE LINEAR STRUCTURE BY EARLY EVENING. OTHER STORMS THAT FORM TO THE SOUTH WILL LIKELY BE MORE MULTI-CELLULAR IN NATURE WITH MAINLY WIND THREATS. SO OVERALL CONFIDENCE IS MODEST BUT WITH PROGRESSIVE STORMS...TIME WINDOW LOOKS MORE CERTAIN...FROM 19Z TO 01Z. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 335 AM CDT MON JUL 22 2013 MAIN FORECAST CONCERNS ARE ON THE POTENTIAL FOR SEVERE THUNDERSTORMS THIS AFTERNOON INTO EARLY THIS EVENING. LATEST WATER VAPOR IMAGERY SHOWED A TROUGH EXTENDING FROM SOUTHERN MANITOBA SOUTH THROUGH THE EASTERN DAKOTAS AND MOVING EAST. SURFACE OBSERVATIONS SHOWED LOW PRESSURE OVER FAR SOUTHEAST MANITOBA...ALONG THE NORTH DAKOTA/MANITOBA BORDER. A COLD FRONT EXTENDED FROM EASTERN NORTH DAKOTA SOUTH THROUGH NORTH CENTRAL SOUTH DAKOTA AND WAS MOVING SOUTHEAST. THE COLD FRONT WILL BE THE FOCUS FOR THUNDERSTORM DEVELOPMENT LATE THIS MORNING INTO THIS AFTERNOON. THE COLD FRONT WILL CONTINUE ITS SOUTHEAST MOVEMENT THIS MORNING AND BY LATE MORNING IS EXPECTED TO EXTEND FROM THE ARROWHEAD OF MINNESOTA SOUTH TO ALONG THE INTERSTATE 35 CORRIDOR. THE FRONT LOOKS TO PUSH INTO SOUTHEAST MINNESOTA AND NORTHEAST IOWA EARLY THIS AFTERNOON THEN MARCH EAST ACROSS THE FORECAST AREA THROUGH THE AFTERNOON HOURS. THE NAM AND GFS MLCAPE VALUES CLIMB INTO THE 1500 TO 2500 J/KG RANGE AHEAD OF THE FRONT. RUC FORECAST SOUNDINGS SHOW SURFACE BASED CAPE VALUES CLIMBING TO AROUND 3000 J/KG. 0-6 KM BULK SHEAR ISN/T OVERLY IMPRESSIVE...HOVERING AROUND 30 KTS. MOST OF THIS SHEAR IS LOCATED IN THE 0-3 KM LAYER AND ORIENTED PERPENDICULAR TO THE FRONT...SUGGESTING A LINEAR MODE TO THE CONVECTION WITH THE POTENTIAL FOR DAMAGING WINDS. THE 0-1 KM SHEAR ALSO RAMPS UP THIS AFTERNOON...INCREASING TO AROUND 22 KTS. CONVERGENCE ALONG THE FRONT IS ALSO NOT OVERLY IMPRESSIVE THIS AFTERNOON BUT GIVEN THE INSTABILITY IN PLACE...IT WILL NOT TAKE MUCH TO GET THUNDERSTORMS TO DEVELOP. FORECAST MODELS HAVE BEEN CONSISTENT SHOWING WARMER AIR ALOFT...CENTERED AROUND 800 MB...THAT WILL HAVE TO BE OVERCOME TO GET THUNDERSTORMS TO DEVELOP. THERE APPEARS THAT THERE WILL BE ENOUGH HEATING THIS AFTERNOON AT THE SURFACE AND SLIGHT COOLING ALOFT TO WEAKEN THE CAP. FORECAST SOUNDINGS REALLY WEAKEN THE CAP BY MID AFTERNOON. ALSO...GIVEN THE INCREASING 0-1 KM SHEAR THIS AFTERNOON WILL HAVE TO KEEP AN EYE ON THE POTENTIAL FOR AN ISOLATED TORNADO...ESPECIALLY ALONG AND NORTH OF INTERSTATE 94. SURFACE WINDS TURN TO THE SOUTHWEST JUST AHEAD OF THE FRONT...SO THINKING OVERALL TORNADO THREAT APPEARS LOW AT THIS TIME. CANNOT RULE OUT SOME SEVERE HAIL THIS AFTERNOON GIVEN THE STRONG CAPE IN THE HAIL GROWTH ZONE. THINKING THE PRIMARY SEVERE THREAT TODAY SHOULD BE DAMAGING WINDS. THE 22.06 HRRR SHOWS STORMS ERUPTING ALONG THE COLD FRONT IN THE 19 TO 21Z TIMEFRAME ACROSS WEST CENTRAL WISCONSIN INTO SOUTHEAST MINNESOTA. THE 22.00 HIRES ARW ALSO SHOWS CONVECTION ERUPTING ACROSS THESE AREAS BUT LATER...IN THE 21 TO 00Z TIMEFRAME. GIVEN THAT THE MAJORITY OF THE MESOSCALE MODELS ARE CONVECTING ALONG THE FRONT...CONFIDENCE IS INCREASING THAT STORMS WILL INDEED DEVELOP THIS AFTERNOON. HIGH TEMPERATURES TODAY WILL CLIMB INTO THE LOWER TO MIDDLE 80S AHEAD OF THE FRONT. DEWPOINTS ARE EXPECTED TO CLIMB INTO THE UPPER 60S TO AROUND 70...MAKING IT FEEL A LITTLE ON THE MUGGY SIDE. THE FRONT WILL EXIT THE FORECAST AREA LATE THIS EVENING INTO THE OVERNIGHT WITH HIGH PRESSURE BUILDING IN ITS WAKE. A STRATUS DECK COULD DEVELOP IN THE WAKE OF THE COLD FRONT LEADING TO MOSTLY CLOUDY SKIES DURING THE OVERNIGHT HOURS. OTHERWISE...SKIES WILL RANGE FROM PARTLY CLOUDY TO MOSTLY CLEAR WITH OVERNIGHT LOWS FALLING INTO THE UPPER 50S TO LOWER 60S. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 335 AM CDT MON JUL 22 2013 SURFACE HIGH PRESSURE WILL BE IN CONTROL ACROSS THE REGION ON TUESDAY PROVIDING DRY CONDITIONS AND MORE SEASONABLE TEMPERATURES. NORTHERLY WINDS WILL USHER IN A MUCH DRIER AIRMASS WITH DEWPOINTS FALLING INT THE LOWER 50S. HIGH TEMPERATURES WILL RANGE FROM THE LOWER 70S OVER NORTHERN WISCONSIN TO THE THE UPPER 70S TO AROUND 80 ACROSS NORTHEAST IOWA. THE HIGH WILL BE POSITIONED DIRECTLY OVER THE FORECAST AREA TUESDAY NIGHT LEADING TO CALM WINDS AND CLEAR SKIES. THIS WILL SET THE STAGE FOR FOG DEVELOPMENT...ESPECIALLY IN VALLEY LOCATIONS AND OVER THE CENTRAL WISCONSIN CRANBERRY COUNTRY. OVERNIGHT LOWS TUESDAY NIGHT WILL FALL INTO THE 50S...WITH LOW LYING AREAS SUCH AS SPARTA AND BLACK RIVER FALLS FALLING INTO THE UPPER 40S. THE HIGH SLIDES EAST OF THE REGION ON WEDNESDAY. A SHORTWAVE TROUGH MOVES INTO THE REGION LATE WEDNESDAY NIGHT INTO THURSDAY...IN NORTHWEST FLOW ALOFT...BRINGING CHANCES FOR SHOWERS AND THUNDERSTORMS TO THE AREA. A COLD FRONT THEN PUSHES ACROSS THE UPPER MISSISSIPPI RIVER VALLEY LATE THURSDAY INTO FRIDAY AS A TROUGH DIGS SOUTHWARD OUT OF ONTARIO. AN UNSEASONABLY COOL AIRMASS MOVES INTO THE REGION IN THE WAKE OF THE FRONT FOR FRIDAY INTO THE WEEKEND. 850 MB TEMPERATURE STANDARDIZED ANOMALIES FALL TO NEGATIVE 2.5 SATURDAY INTO SUNDAY. PLAN ON HIGH TEMPERATURES IN THE LOWER 70S OVER THE WEEKEND. WEAK SHORTWAVES MAY BRING SCATTERED SHOWERS AND THUNDERSTORMS TO THE AREA ON SATURDAY..WITH CHANCES SHIFTING SOUTH OF INTERSTATE 90 DURING THE DAY ON SUNDAY. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 623 AM CDT MON JUL 22 2013 SOUTHERLY FLOW AHEAD OF A COLD FRONT IN WESTERN MINNESOTA HAS BEEN BRINGING UP MORE MOISTURE INTO THE REGION AND TAF SITES. THIS MOISTURE HAS MANIFESTED ITSELF AS LIFR TO IFR STRATUS...WITH EVEN SOME FOG RANGING FROM VLIFR TO IFR AT RST. CEILINGS AND VISIBILITIES WILL GRADUALLY RISE THROUGH MORNING DUE TO DAYTIME MIXING...WITH BOTH TAF SITES LIKELY VFR BY 16Z. DURING THE AFTERNOON...THE COLD FRONT IS EXPECTED TO MOVE THROUGH THE TAF SITES. THUNDERSTORMS LOOK LIKELY TO ACCOMPANY THE FRONT...SO IT IS JUST A MATTER OF TIMING. BASED ON A CONSENSUS OF HIGH RESOLUTION MODEL FORECASTS...SPED UP THE TIMING FROM THE 06Z TAFS...IMPACTING RST BETWEEN 19-22Z AND LSE BETWEEN 20-23Z. ITS POSSIBLE THE STORMS COULD EXIT THE TAF SITES A LITTLE SOONER. VISIBILITIES AND CEILING MAY FALL TO MVFR OR PERHAPS EVEN LOWER BRIEFLY. ADDITIONALLY...POTENTIAL EXISTS FOR THE STORMS TO BRING STRONG TO DAMAGING WIND GUSTS AND LARGE HAIL. CONFIDENCE IS TOO LOW TO MENTION ANY SEVERE POTENTIAL DIRECTLY IN THE TAFS AT THIS TIME. VFR CONDITIONS WITH WINDS SHIFTING TO THE NORTHWEST ARE EXPECTED BEHIND THE FRONT. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ MESOSCALE....SHEA SHORT TERM...WETENKAMP LONG TERM....WETENKAMP AVIATION.....AJ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
623 AM CDT MON JUL 22 2013 .MESOSCALE DISCUSSION... ISSUED AT 623 AM CDT MON JUL 22 2013 19.05Z THROUGH 19.09Z HRRR MODEL FORECASTS ARE STAYING EXTREMELY CONSISTENT WITH DEVELOPMENT OF CONVECTION ALONG THE APPROACHING COLD FRONT THIS AFTERNOON. CONVECTION FIRES IN SOUTHEAST MN AND NORTHWEST WI BETWEEN 18-20Z...THEN MARCHES SOUTHEAST THROUGH THE FORECAST AREA...LIKELY EXITING BY 00Z. AN INTERESTING SIGNAL SHOWING UP IS A SPLIT IN THE CONVECTION AREAS ALONG THE FRONT. ONE AREA TRACKS MORE ACROSS CENTRAL/NORTHERN WI...CLOSER TO THE DYNAMICS ASSOCIATED WITH THE SHORTWAVE TROUGH CROSSING LAKE SUPERIOR AND NORTHERN ONTARIO. THE OTHER AREA DROPS DOWN THROUGH EASTERN IOWA...FOLLOWING THE HIGHER INSTABILITY. THIS SIGNAL SHOWS UP TOO IN THE 22.06Z NAM...OUR LOCAL WRF RUN...THE 22.00Z HIRES ARW AND NSSL WRF. WE WILL SEE IF THIS HAPPENS IN REALITY. SPECIFIC STORM SCALE DATA FROM THE HRRR DOES INDICATE POTENTIAL FOR SOME DISCRETE STORM CELLS UPON INITIATION...EVENTUALLY TURNING INTO LINEAR STRUCTURES. THUS...INITIAL STORMS COULD POSE BOTH A LARGE HAIL AND DAMAGING WIND CONCERN...FOLLOWED BY DAMAGING WINDS THEREAFTER. GOING HAZARD CONCERNS IN THE HWO AND OTHER SERVICES REMAIN ON TRACK. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 335 AM CDT MON JUL 22 2013 MAIN FORECAST CONCERNS ARE ON THE POTENTIAL FOR SEVERE THUNDERSTORMS THIS AFTERNOON INTO EARLY THIS EVENING. LATEST WATER VAPOR IMAGERY SHOWED A TROUGH EXTENDING FROM SOUTHERN MANITOBA SOUTH THROUGH THE EASTERN DAKOTAS AND MOVING EAST. SURFACE OBSERVATIONS SHOWED LOW PRESSURE OVER FAR SOUTHEAST MANITOBA...ALONG THE NORTH DAKOTA/MANITOBA BORDER. A COLD FRONT EXTENDED FROM EASTERN NORTH DAKOTA SOUTH THROUGH NORTH CENTRAL SOUTH DAKOTA AND WAS MOVING SOUTHEAST. THE COLD FRONT WILL BE THE FOCUS FOR THUNDERSTORM DEVELOPMENT LATE THIS MORNING INTO THIS AFTERNOON. THE COLD FRONT WILL CONTINUE ITS SOUTHEAST MOVEMENT THIS MORNING AND BY LATE MORNING IS EXPECTED TO EXTEND FROM THE ARROWHEAD OF MINNESOTA SOUTH TO ALONG THE INTERSTATE 35 CORRIDOR. THE FRONT LOOKS TO PUSH INTO SOUTHEAST MINNESOTA AND NORTHEAST IOWA EARLY THIS AFTERNOON THEN MARCH EAST ACROSS THE FORECAST AREA THROUGH THE AFTERNOON HOURS. THE NAM AND GFS MLCAPE VALUES CLIMB INTO THE 1500 TO 2500 J/KG RANGE AHEAD OF THE FRONT. RUC FORECAST SOUNDINGS SHOW SURFACE BASED CAPE VALUES CLIMBING TO AROUND 3000 J/KG. 0-6 KM BULK SHEAR ISN/T OVERLY IMPRESSIVE...HOVERING AROUND 30 KTS. MOST OF THIS SHEAR IS LOCATED IN THE 0-3 KM LAYER AND ORIENTED PERPENDICULAR TO THE FRONT...SUGGESTING A LINEAR MODE TO THE CONVECTION WITH THE POTENTIAL FOR DAMAGING WINDS. THE 0-1 KM SHEAR ALSO RAMPS UP THIS AFTERNOON...INCREASING TO AROUND 22 KTS. CONVERGENCE ALONG THE FRONT IS ALSO NOT OVERLY IMPRESSIVE THIS AFTERNOON BUT GIVEN THE INSTABILITY IN PLACE...IT WILL NOT TAKE MUCH TO GET THUNDERSTORMS TO DEVELOP. FORECAST MODELS HAVE BEEN CONSISTENT SHOWING WARMER AIR ALOFT...CENTERED AROUND 800 MB...THAT WILL HAVE TO BE OVERCOME TO GET THUNDERSTORMS TO DEVELOP. THERE APPEARS THAT THERE WILL BE ENOUGH HEATING THIS AFTERNOON AT THE SURFACE AND SLIGHT COOLING ALOFT TO WEAKEN THE CAP. FORECAST SOUNDINGS REALLY WEAKEN THE CAP BY MID AFTERNOON. ALSO...GIVEN THE INCREASING 0-1 KM SHEAR THIS AFTERNOON WILL HAVE TO KEEP AN EYE ON THE POTENTIAL FOR AN ISOLATED TORNADO...ESPECIALLY ALONG AND NORTH OF INTERSTATE 94. SURFACE WINDS TURN TO THE SOUTHWEST JUST AHEAD OF THE FRONT...SO THINKING OVERALL TORNADO THREAT APPEARS LOW AT THIS TIME. CANNOT RULE OUT SOME SEVERE HAIL THIS AFTERNOON GIVEN THE STRONG CAPE IN THE HAIL GROWTH ZONE. THINKING THE PRIMARY SEVERE THREAT TODAY SHOULD BE DAMAGING WINDS. THE 22.06 HRRR SHOWS STORMS ERUPTING ALONG THE COLD FRONT IN THE 19 TO 21Z TIMEFRAME ACROSS WEST CENTRAL WISCONSIN INTO SOUTHEAST MINNESOTA. THE 22.00 HIRES ARW ALSO SHOWS CONVECTION ERUPTING ACROSS THESE AREAS BUT LATER...IN THE 21 TO 00Z TIMEFRAME. GIVEN THAT THE MAJORITY OF THE MESOSCALE MODELS ARE CONVECTING ALONG THE FRONT...CONFIDENCE IS INCREASING THAT STORMS WILL INDEED DEVELOP THIS AFTERNOON. HIGH TEMPERATURES TODAY WILL CLIMB INTO THE LOWER TO MIDDLE 80S AHEAD OF THE FRONT. DEWPOINTS ARE EXPECTED TO CLIMB INTO THE UPPER 60S TO AROUND 70...MAKING IT FEEL A LITTLE ON THE MUGGY SIDE. THE FRONT WILL EXIT THE FORECAST AREA LATE THIS EVENING INTO THE OVERNIGHT WITH HIGH PRESSURE BUILDING IN ITS WAKE. A STRATUS DECK COULD DEVELOP IN THE WAKE OF THE COLD FRONT LEADING TO MOSTLY CLOUDY SKIES DURING THE OVERNIGHT HOURS. OTHERWISE...SKIES WILL RANGE FROM PARTLY CLOUDY TO MOSTLY CLEAR WITH OVERNIGHT LOWS FALLING INTO THE UPPER 50S TO LOWER 60S. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 335 AM CDT MON JUL 22 2013 SURFACE HIGH PRESSURE WILL BE IN CONTROL ACROSS THE REGION ON TUESDAY PROVIDING DRY CONDITIONS AND MORE SEASONABLE TEMPERATURES. NORTHERLY WINDS WILL USHER IN A MUCH DRIER AIRMASS WITH DEWPOINTS FALLING INT THE LOWER 50S. HIGH TEMPERATURES WILL RANGE FROM THE LOWER 70S OVER NORTHERN WISCONSIN TO THE THE UPPER 70S TO AROUND 80 ACROSS NORTHEAST IOWA. THE HIGH WILL BE POSITIONED DIRECTLY OVER THE FORECAST AREA TUESDAY NIGHT LEADING TO CALM WINDS AND CLEAR SKIES. THIS WILL SET THE STAGE FOR FOG DEVELOPMENT...ESPECIALLY IN VALLEY LOCATIONS AND OVER THE CENTRAL WISCONSIN CRANBERRY COUNTRY. OVERNIGHT LOWS TUESDAY NIGHT WILL FALL INTO THE 50S...WITH LOW LYING AREAS SUCH AS SPARTA AND BLACK RIVER FALLS FALLING INTO THE UPPER 40S. THE HIGH SLIDES EAST OF THE REGION ON WEDNESDAY. A SHORTWAVE TROUGH MOVES INTO THE REGION LATE WEDNESDAY NIGHT INTO THURSDAY...IN NORTHWEST FLOW ALOFT...BRINGING CHANCES FOR SHOWERS AND THUNDERSTORMS TO THE AREA. A COLD FRONT THEN PUSHES ACROSS THE UPPER MISSISSIPPI RIVER VALLEY LATE THURSDAY INTO FRIDAY AS A TROUGH DIGS SOUTHWARD OUT OF ONTARIO. AN UNSEASONABLY COOL AIRMASS MOVES INTO THE REGION IN THE WAKE OF THE FRONT FOR FRIDAY INTO THE WEEKEND. 850 MB TEMPERATURE STANDARDIZED ANOMALIES FALL TO NEGATIVE 2.5 SATURDAY INTO SUNDAY. PLAN ON HIGH TEMPERATURES IN THE LOWER 70S OVER THE WEEKEND. WEAK SHORTWAVES MAY BRING SCATTERED SHOWERS AND THUNDERSTORMS TO THE AREA ON SATURDAY..WITH CHANCES SHIFTING SOUTH OF INTERSTATE 90 DURING THE DAY ON SUNDAY. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 623 AM CDT MON JUL 22 2013 SOUTHERLY FLOW AHEAD OF A COLD FRONT IN WESTERN MINNESOTA HAS BEEN BRINGING UP MORE MOISTURE INTO THE REGION AND TAF SITES. THIS MOISTURE HAS MANIFESTED ITSELF AS LIFR TO IFR STRATUS...WITH EVEN SOME FOG RANGING FROM VLIFR TO IFR AT RST. CEILINGS AND VISIBILITIES WILL GRADUALLY RISE THROUGH MORNING DUE TO DAYTIME MIXING...WITH BOTH TAF SITES LIKELY VFR BY 16Z. DURING THE AFTERNOON...THE COLD FRONT IS EXPECTED TO MOVE THROUGH THE TAF SITES. THUNDERSTORMS LOOK LIKELY TO ACCOMPANY THE FRONT...SO IT IS JUST A MATTER OF TIMING. BASED ON A CONSENSUS OF HIGH RESOLUTION MODEL FORECASTS...SPED UP THE TIMING FROM THE 06Z TAFS...IMPACTING RST BETWEEN 19-22Z AND LSE BETWEEN 20-23Z. ITS POSSIBLE THE STORMS COULD EXIT THE TAF SITES A LITTLE SOONER. VISIBILITIES AND CEILING MAY FALL TO MVFR OR PERHAPS EVEN LOWER BRIEFLY. ADDITIONALLY...POTENTIAL EXISTS FOR THE STORMS TO BRING STRONG TO DAMAGING WIND GUSTS AND LARGE HAIL. CONFIDENCE IS TOO LOW TO MENTION ANY SEVERE POTENTIAL DIRECTLY IN THE TAFS AT THIS TIME. VFR CONDITIONS WITH WINDS SHIFTING TO THE NORTHWEST ARE EXPECTED BEHIND THE FRONT. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ MESOSCALE...AJ SHORT TERM...WETENKAMP LONG TERM...WETENKAMP AVIATION...AJ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
335 AM CDT MON JUL 22 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 335 AM CDT MON JUL 22 2013 MAIN FORECAST CONCERNS ARE ON THE POTENTIAL FOR SEVERE THUNDERSTORMS THIS AFTERNOON INTO EARLY THIS EVENING. LATEST WATER VAPOR IMAGERY SHOWED A TROUGH EXTENDING FROM SOUTHERN MANITOBA SOUTH THROUGH THE EASTERN DAKOTAS AND MOVING EAST. SURFACE OBSERVATIONS SHOWED LOW PRESSURE OVER FAR SOUTHEAST MANITOBA...ALONG THE NORTH DAKOTA/MANITOBA BORDER. A COLD FRONT EXTENDED FROM EASTERN NORTH DAKOTA SOUTH THROUGH NORTH CENTRAL SOUTH DAKOTA AND WAS MOVING SOUTHEAST. THE COLD FRONT WILL BE THE FOCUS FOR THUNDERSTORM DEVELOPMENT LATE THIS MORNING INTO THIS AFTERNOON. THE COLD FRONT WILL CONTINUE ITS SOUTHEAST MOVEMENT THIS MORNING AND BY LATE MORNING IS EXPECTED TO EXTEND FROM THE ARROWHEAD OF MINNESOTA SOUTH TO ALONG THE INTERSTATE 35 CORRIDOR. THE FRONT LOOKS TO PUSH INTO SOUTHEAST MINNESOTA AND NORTHEAST IOWA EARLY THIS AFTERNOON THEN MARCH EAST ACROSS THE FORECAST AREA THROUGH THE AFTERNOON HOURS. THE NAM AND GFS MLCAPE VALUES CLIMB INTO THE 1500 TO 2500 J/KG RANGE AHEAD OF THE FRONT. RUC FORECAST SOUNDINGS SHOW SURFACE BASED CAPE VALUES CLIMBING TO AROUND 3000 J/KG. 0-6 KM BULK SHEAR ISN/T OVERLY IMPRESSIVE...HOVERING AROUND 30 KTS. MOST OF THIS SHEAR IS LOCATED IN THE 0-3 KM LAYER AND ORIENTED PERPENDICULAR TO THE FRONT...SUGGESTING A LINEAR MODE TO THE CONVECTION WITH THE POTENTIAL FOR DAMAGING WINDS. THE 0-1 KM SHEAR ALSO RAMPS UP THIS AFTERNOON...INCREASING TO AROUND 22 KTS. CONVERGENCE ALONG THE FRONT IS ALSO NOT OVERLY IMPRESSIVE THIS AFTERNOON BUT GIVEN THE INSTABILITY IN PLACE...IT WILL NOT TAKE MUCH TO GET THUNDERSTORMS TO DEVELOP. FORECAST MODELS HAVE BEEN CONSISTENT SHOWING WARMER AIR ALOFT...CENTERED AROUND 800 MB...THAT WILL HAVE TO BE OVERCOME TO GET THUNDERSTORMS TO DEVELOP. THERE APPEARS THAT THERE WILL BE ENOUGH HEATING THIS AFTERNOON AT THE SURFACE AND SLIGHT COOLING ALOFT TO WEAKEN THE CAP. FORECAST SOUNDINGS REALLY WEAKEN THE CAP BY MID AFTERNOON. ALSO...GIVEN THE INCREASING 0-1 KM SHEAR THIS AFTERNOON WILL HAVE TO KEEP AN EYE ON THE POTENTIAL FOR AN ISOLATED TORNADO...ESPECIALLY ALONG AND NORTH OF INTERSTATE 94. SURFACE WINDS TURN TO THE SOUTHWEST JUST AHEAD OF THE FRONT...SO THINKING OVERALL TORNADO THREAT APPEARS LOW AT THIS TIME. CANNOT RULE OUT SOME SEVERE HAIL THIS AFTERNOON GIVEN THE STRONG CAPE IN THE HAIL GROWTH ZONE. THINKING THE PRIMARY SEVERE THREAT TODAY SHOULD BE DAMAGING WINDS. THE 22.06 HRRR SHOWS STORMS ERUPTING ALONG THE COLD FRONT IN THE 19 TO 21Z TIMEFRAME ACROSS WEST CENTRAL WISCONSIN INTO SOUTHEAST MINNESOTA. THE 22.00 HIRES ARW ALSO SHOWS CONVECTION ERUPTING ACROSS THESE AREAS BUT LATER...IN THE 21 TO 00Z TIMEFRAME. GIVEN THAT THE MAJORITY OF THE MESOSCALE MODELS ARE CONVECTING ALONG THE FRONT...CONFIDENCE IS INCREASING THAT STORMS WILL INDEED DEVELOP THIS AFTERNOON. HIGH TEMPERATURES TODAY WILL CLIMB INTO THE LOWER TO MIDDLE 80S AHEAD OF THE FRONT. DEWPOINTS ARE EXPECTED TO CLIMB INTO THE UPPER 60S TO AROUND 70...MAKING IT FEEL A LITTLE ON THE MUGGY SIDE. THE FRONT WILL EXIT THE FORECAST AREA LATE THIS EVENING INTO THE OVERNIGHT WITH HIGH PRESSURE BUILDING IN ITS WAKE. A STRATUS DECK COULD DEVELOP IN THE WAKE OF THE COLD FRONT LEADING TO MOSTLY CLOUDY SKIES DURING THE OVERNIGHT HOURS. OTHERWISE...SKIES WILL RANGE FROM PARTLY CLOUDY TO MOSTLY CLEAR WITH OVERNIGHT LOWS FALLING INTO THE UPPER 50S TO LOWER 60S. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 335 AM CDT MON JUL 22 2013 SURFACE HIGH PRESSURE WILL BE IN CONTROL ACROSS THE REGION ON TUESDAY PROVIDING DRY CONDITIONS AND MORE SEASONABLE TEMPERATURES. NORTHERLY WINDS WILL USHER IN A MUCH DRIER AIRMASS WITH DEWPOINTS FALLING INT THE LOWER 50S. HIGH TEMPERATURES WILL RANGE FROM THE LOWER 70S OVER NORTHERN WISCONSIN TO THE THE UPPER 70S TO AROUND 80 ACROSS NORTHEAST IOWA. THE HIGH WILL BE POSITIONED DIRECTLY OVER THE FORECAST AREA TUESDAY NIGHT LEADING TO CALM WINDS AND CLEAR SKIES. THIS WILL SET THE STAGE FOR FOG DEVELOPMENT...ESPECIALLY IN VALLEY LOCATIONS AND OVER THE CENTRAL WISCONSIN CRANBERRY COUNTRY. OVERNIGHT LOWS TUESDAY NIGHT WILL FALL INTO THE 50S...WITH LOW LYING AREAS SUCH AS SPARTA AND BLACK RIVER FALLS FALLING INTO THE UPPER 40S. THE HIGH SLIDES EAST OF THE REGION ON WEDNESDAY. A SHORTWAVE TROUGH MOVES INTO THE REGION LATE WEDNESDAY NIGHT INTO THURSDAY...IN NORTHWEST FLOW ALOFT...BRINGING CHANCES FOR SHOWERS AND THUNDERSTORMS TO THE AREA. A COLD FRONT THEN PUSHES ACROSS THE UPPER MISSISSIPPI RIVER VALLEY LATE THURSDAY INTO FRIDAY AS A TROUGH DIGS SOUTHWARD OUT OF ONTARIO. AN UNSEASONABLY COOL AIRMASS MOVES INTO THE REGION IN THE WAKE OF THE FRONT FOR FRIDAY INTO THE WEEKEND. 850 MB TEMPERATURE STANDARDIZED ANOMALIES FALL TO NEGATIVE 2.5 SATURDAY INTO SUNDAY. PLAN ON HIGH TEMPERATURES IN THE LOWER 70S OVER THE WEEKEND. WEAK SHORTWAVES MAY BRING SCATTERED SHOWERS AND THUNDERSTORMS TO THE AREA ON SATURDAY..WITH CHANCES SHIFTING SOUTH OF INTERSTATE 90 DURING THE DAY ON SUNDAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1100 PM CDT SUN JUL 21 2013 FOG/STRATUS DEVELOPMENT A CONCERN OVERNIGHT. BUFKIT SOUNDINGS INDICATE A MOIST NEAR SFC LAYER //AIDED BY RAINFALL TODAY// UNDER AN INVERSION NEAR 900 MB. T/TD SPREAD OF 3-7 DEGREES ALREADY AT 03Z WITH CLEAR SKIES OVERHEAD. HOWEVER...THE SOUNDINGS KEEP WINDS STIRRED JUST OFF THE SFC..10+ KTS BY 200 FT. THIS WOULD GENERALLY FAVOR MORE OF A STRATUS THREAT THAN DENSE FOG. WILL STAY WITH THIS TREND IN THE TAFS. COLD FRONT SLATED TO SINK ACROSS THE AREA LATER FRIDAY AFTERNOON/EVENING...WITH A SWITCH TO NORTHWEST WINDS NEAR/SHORTLY AFTER 00Z. LOW LEVEL INVERSION WILL SERVE TO KEEP THE ATMOSPHERE CAPPED FOR MUCH OF THE DAY...BUT THE FRONT SHOULD PROVIDE ENOUGH FORCING TO FIRE A LINE OF SHRA/TS BETWEEN 19-21Z...WHICH WILL TRACK ACROSS THE TAF SITES. COULD BE SOME STRONG/SEVERE STORMS. CONFIDENCE INCREASING IN THIS SCENARIO AND WILL REFLECT THIS IN THE TAFS. EXPECTING SOME ENHANCED GUSTINESS AROUND THE STRONGER STORMS. PCPN WILL CLEAR WITH THE BOUNDARY...BUT CLOUDS COULD LINGER THROUGH THE EVENING HOURS. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...WETENKAMP LONG TERM...WETENKAMP AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1159 PM CDT SUN JUL 21 2013 UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE .SHORT TERM...TONIGHT AND MONDAY ISSUED AT 330 PM CDT SUN JUL 21 2013 LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A COUPLE SHORTWAVES UPSTREAM...ONE OVER WESTERN WISCONSIN WHICH IS RESPONSIBLE FOR THE CLUSTER OF SHOWERS AND STORMS MOVING OVER CENTRAL WISCONSIN...AND ANOTHER OVER IOWA. MAINLY THE SOUTHERN PORTION OF THE FORECAST AREA WILL BE IMPACTED WITH THESE STORMS FOR THE REST OF THE AFTERNOON...BUT NO SEVERE WEATHER IS EXPECTED. FURTHER UPSTREAM...THE NEXT SHORTWAVE IS PRODUCING STORMS OVER FAR SOUTH-CENTRAL CANADA AND NORTHERN NORTH DAKOTA WHICH WILL ARRIVE TOMORROW. PRECIP CHANCES FOR THE REST OF TODAY AND SEVERE WEATHER CHANCES TOMORROW ARE THE MAIN FORECAST CONCERNS. TONIGHT...SHORTWAVE IMPULSES MOVING EAST ACROSS THE REGION WILL TAKE UNTIL MID TO LATE EVENING TO EXIT. AS A RESULT...POTENTIAL WILL BE THERE FOR ISOLATED TO SCATTERED THUNDERSTORMS UNTIL THEN OVER THE SOUTHERN FORECAST AREA...EVEN THOUGH THE MAIN CLUSTER WILL HAVE PROBABLY EXITED BY THE START OF THE EVENING. PLENTY OF CLEARING OCCURRING UPSTREAM OF THE SHORTWAVES...THOUGH MODELS DEPICT WEAK ISENTROPIC ASCENT CONTINUING THROUGH THE NIGHT. AM THINKING WILL SEE A PERIOD OF SUBSIDENCE BEHIND THE WAVE...WHICH COULD LEAD TO A SEVERAL HOURS OF MOSTLY CLEAR TO PARTLY CLOUDY CONDITIONS. NOT SURE HOW LONG THIS WILL LAST...BUT 850MB THETAE ADVECTION DOES RAMP UP LATE AHEAD OF THE SHORTWAVE CURRENTLY MOVING INTO NORTHERN NORTH DAKOTA. NOT OUT OF THE QUESTION THAT CONVECTION COULD APPROACH N-C WISCONSIN LATE TONIGHT. SO WILL SHOW INCREASING CLOUDS AFTER MIDNIGHT ALONG WITH SLIGHT CHANCE TO CHANCE POPS OVER CENTRAL AND NORTH-CENTRAL WISCONSIN. LOWS MAINLY IN THE MID 50S TO LOW 60S. MONDAY...THE NORTH DAKOTA SHORTWAVE WILL MOVE ACROSS NORTHERN WISCONSIN DURING THE MORNING. BOTH THE NAM AND GFS SHOW A DECENT WIND SHIFT OCCURRING AT 700MB SO WOULD NOT BE SURPRISED TO SEE SOME CONVECTION MOVE ACROSS THE NORTH. THEN A STRONG SHORTWAVE OVER WESTERN ONTARIO WILL DRIVE A COLD FRONT ACROSS NORTHWEST WISCONSIN DURING THE AFTERNOON. DEPENDING UPON IF PRECIP OCCURS OVER NORTHERN WISCONSIN AND HOW MUCH DESTABILIZATION CAN OCCUR WITH AMPLE CLOUD COVER...MODIFYING PROGGED SOUNDINGS NEAR RHINELANDER FOR AN 80F/64F PARCEL YIELDS 1700 J/KG OF ML CAPE AT 21Z. WITH 0-6KM BULK SHEAR VALUES OF 30-35KTS...POTENTIAL WILL BE THERE FOR SEVERE STORMS TOMORROW AFTERNOON OVER N-C AND POSSIBLY CENTRAL WISCONSIN TOO. WARM ADVECTION AHEAD OF THE FRONT WILL PUSH HIGHS TO THE UPPER 70S AND MID 80S. .LONG TERM...MONDAY NIGHT THROUGH SUNDAY ISSUED AT 330 PM CDT SUN JUL 21 2013 NOT MUCH CHANGE IN THE OVERALL FORECAST FOR THIS PERIOD AS SHORTWAVE TROFS MOVE THROUGH MEAN TROF POSITION ACROSS GREAT LAKES. LATEST GFS AND ECMWF IN GENERAL AGREEMENT THROUGH MOST OF PERIOD ON STRENGTH AND TIMING OF SYSTEMS. TEMPS WILL BE AOB NORMAL FOR MUCH OF WEEK...AFTER MONDAY. IN FACT...HIGHS NEXT WEEKEND MAY STRUGGLE TO REACH 70 ACROSS PARTS OF THE NORTH AS NW FLOW IS REINFORCED BEHIND LATE WEEK SYSTEM. && .AVIATION...FOR 06Z TAF ISSUANCE ISSUED AT 1159 PM CDT SUN JUL 21 2013 PATCHY IFR/MVFR CIGS WILL LINGER OVER THE REGION OVERNIGHT DUE TO RETURN FLOW AHEAD OF A APPROACHING COLD FRONT. AREAS OF FOG WILL ALSO DEVELOP WHERE CLEAR SKIES PREVAIL. MORE MVFR CIGS AND VSBYS DUE TO SHOWERS AND STORMS LIKELY ALONG THIS FRONT STARTING MONDAY AFTERNOON OVER NORTHWEST WISCONSIN BEFORE REACHING SOUTHEAST WISCONSIN MONDAY NIGHT. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....MPC LONG TERM......JKL AVIATION.......TDH
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
608 PM MDT TUE JUL 23 2013 .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 330 PM MDT TUE JUL 23 2013 AN INFLUX OF MONSOONAL MOISTURE WILL INDICATE A TURN TO A MUCH MORE CLIMATOLOGICALLY NORMAL PERIOD OF UNSETTLED WEATHER BEGINNING WEDNESDAY AND CONTINUING THROUGH MUCH OF THE LONGER TERM. BEFORE THEN...AFTERNOON SATELLITE PIX SHOW SHALLOW CONVECTION BEGINNING TO DEVELOP OVER THE NORTHERN LARAMIE RANGE. A RESULT OF LLVL CONVERGENCE DUE TO A STATIONARY BOUNDARY DRAPED UP ALONG THE FRONT RANGE. DEW POINTS WEST OF THIS BOUNDARY WERE BELOW 30F...WITH RAWLINS REPORTING 11F. MORE AMPLE LLVL MOISTURE EAST OF THIS BOUNDARY AS INDICATED BY 50 DEGREE DEW POINTS. IN FACT...THIS BOUNDARY PUSHED EAST OF KCYS EARLY THIS MORNING DROPPING DEWPOINTS BRIEFLY BACK INTO THE 20S. MOST OF THE CWA WILL REMAIN DRY THIS EVENING...THESE EXCEPTION BEING THE FAR EASTERN ROW OF COUNTIES FROM CHADRON TO BRIDGEPORT. AS HAS BEEN THE CASE THE PAST SEVERAL DAYS...12Z MODEL OUTPUT CONTINUES TO SUGGEST CAP WILL HOLD AND THE AREA WILL REMAIN DRY. EVEN THE LATEST HRRR DEVELOPS CONVECTION JUST EAST OF THE CWFA. PERSISTENCE SAYS OTHERWISE HOWEVER...SO WILL KEEP SLIGHT CHANCES GOING FROM CHADRON AND BRIDGEPORT. IF THE CAP DOES MANAGE TO BREAK...SBCAPES OF 1000 TO 1500 J/KG WOULD BE REALIZED WHICH COULD RESULT IN SOME SEVERE DEVELOPMENT. ANY THUNDERSTORMS WILL WIND DOWN BY LATE EVENING. ATTENTION THEN SHIFTS TO UPSTREAM MOISTURE AND SHORTWAVE EVIDENT ON WV IMAGERY FROM NRN CA/SRN OR EAST INTO UTAH. THIS SUB-TROPICAL MONSOON MOISTURE PLUME AND SHORTWAVE WILL SLOWLY MEANDER NORTH INTO THE REGION ON WEDNESDAY. 12Z MODELS HAVE DELAYED ITS ARRIVAL BY A FEW HOURS. ALTHOUGH THERE IS SOME POTENTIAL FOR DRY LIGHTNING EARLY WEDNESDAY...AM NOT CONFIDENT ON ITS COVERAGE. SO FOR NOW...HAVE MAINTAINED THE INHERITED COVERAGE...BUT HAVE CONFINED IT TO THE SNOWY/SIERRA MADRE RANGES WEDNESDAY MORNING. BY MIDDAY WEDNESDAY...CONVECTION WILL BE DEVELOPING OVER THE SE WYOMING MOUNTAINS AND ADJACENT FOOTHILLS/VALLEY LOCATIONS. PROGD SBCAPES WILL NOT BE PARTICULARLY HIGH (500-800 J/KG). HOWEVER PWATS RISING ABOVE AN INCH ALONG WITH STORM MOTIONS OF 10 KNOTS OR LESS WILL RESULT IN EFFICIENT RAIN PRODUCERS. CAN NOT RULE OUT THE POTENTIAL FOR SMALL HAIL TOO...THOUGH THERMODYNAMIC PARAMETERS ARE NOT FAVORABLE. SHORTWAVE WILL MEANDER ATOP THE CWA WEDNESDAY NIGHT WHICH SHOULD AID IN THE CONTINUATION OF NOCTURNAL CONVECTION. MID/UPPER-LEVEL FLOW WILL TURN NORTHWEST FOR THURSDAY BEHIND DEPARTING SHORTWAVE. AT THE SFC...A WEAK COOL FRONT ALONG WITH FAVORABLE UPSLOPE BEHIND FROPA WILL SET THE STAGE FOR ANOTHER ROUND OF AFTERNOON AND EVENING SHOWERS/THUNDERSTORMS. AGAIN AMPLE MOISTURE WILL ACT TO LIMIT SEVERE POTENTIAL...ONLY YIELDING SBCAPES OF 500-800 J/KG. STORM MOTIONS WILL AGAIN BE LESS THAN 10 KNOTS. THE THICKER CLOUD CANOPY ALONG WITH WEAK COLD FROPA ON THURSDAY WILL CAUSE TEMPERATURES TO COOL FROM THE UPPER 80S ON WEDNESDAY INTO THE LOWER 80S ON THURSDAY. .LONG TERM...(THURSDAY NIGHT THROUGH MONDAY) ISSUED AT 330 PM MDT TUE JUL 23 2013 MONSOONAL MOISTURE WILL CONTINUE TO STREAM INTO THE REGION ON FRIDAY THROUGH THE WEEKEND. SHORTWAVE MOVES SOUTHWARD ACROSS THE NORTHERN HIGH PLAINS ON THURSDAY NIGHT WITH RISING SFC PRESSURES BEHIND IT OVER THE PLAINS. THIS RESULTS IN GOOD SOUTHEAST UPSLOPE BY FRIDAY WITH PW VALUES OF 1.00-1.25 INCHES OVER MOST AREAS ALONG AND EAST OF THE LARAMIE RANGE. WIDESPREAD QPF IS DEPICTED ON BOTH THE GFS AND ECMWF BY FRIDAY AFTN/EVENING. WITH DEEP LAYER SHEAR OF 50 KTS AND CAPE VALUES OF 1250-1500 J/KG...A FEW STRONG TO SEVERE STORMS COULD BE POSSIBLE OVER THE PLAINS. THE STEERING FLOW IS A LITTLE TOO FAST FOR MAJOR FLASH FLOODING CONCERNS ON FRIDAY. UPPER LEVEL RIDGE AXIS IS POSITIONED OVER WESTERN WY BY SATURDAY AFTN...WITH NORTHWESTERLY MIDLEVEL FLOW PERSISTING IN THE CWA. CONVECTIVE PARAMETERS APPEAR VERY SIMILAR TO FRIDAY...SO GENERALLY CARRIED THE SAME POPS. RIDGE AXIS IS ALMOST DIRECTLY OVER THE CWA BY SUNDAY WITH STEERING FLOW BECOMING MORE WESTERLY AND SOMEWHAT SLOWER THAN THE PREVIOUS DAYS. SHORTWAVE ROTATES THROUGH THE AREA DURING PEAK HEATING AND WITH PW VALUES REMAINING ABOVE NORMAL...EXPECT ANOTHER DAY OF GOOD STORM COVERAGE. DRIER 700-500MB FLOW CREEPS INTO THE REGION BY MONDAY WHICH COULD RESULT IN MORE ISOLATED TSTM CHANCES. TEMPS THROUGHOUT THE PERIOD WILL BE SLIGHTLY BELOW AVERAGE WITH THE MOIST AIRMASS AND RATHER CLOUDY CONDITIONS. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY AFTERNOON) ISSUED AT 605 PM MDT TUE JUL 23 2013 ISOLATED SHOWERS AND THUNDERSTORMS EAST OF THE LARAMIE RANGE WILL DIE OFF LATER THIS EVENING. THEN MOSTLY CLEAR SKIES WITH INCREASING HIGH CLOUDS LATE TONIGHT INTO TOMORROW. WINDS WILL BE ON THE LIGHT SIDE THROUGH WEDNESDAY...OUTSIDE OF GUSTY WINDS WITH ANY SHOWER OR THUNDERSTORM ACTIVITY. THUNDERSTORMS EXPECTED MAINLY WEST OF THE LARAMIE RANGE WEDNESDAY AFTERNOON. && .FIRE WEATHER... ISSUED AT 330 PM MDT TUE JUL 23 2013 MONSOONAL MOISTURE WILL RETURN TO THE DISTRICT IN EARNEST DURING THE DAY ON WEDNESDAY. AS THIS OCCURS...WE MAY BE ABLE TO SEE SOME HIGH-BASED SHOWER/THUNDERSTORM DEVELOPMENT MAINLY OVER THE SNOWY AND SIERRA MADRE RANGES. AM NOT CONFIDENT OF WHETHER OR NOT THIS WILL OCCUR...BUT IF IT DOES THE BEST TIME WILL BE BETWEEN 6AM AND NOON WEDNESDAY. AFTER THAT...BETTER CHANCES FOR SHOWERS AND THUNDERSTORMS WILL RETURN TO THE DISTRICT BEGINNING WEDNESDAY AFTERNOON AND CONTINUING INTO THE UPCOMING WEEKEND. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...NONE. NE...NONE. && $$ SHORT TERM...HAHN LONG TERM...FINCH AVIATION...LIEBL FIRE WEATHER...HAHN
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
953 PM MST TUE JUL 23 2013 .SYNOPSIS... MONSOON MOISTURE AND HUMID CONDITIONS WILL CONTINUE ACROSS THE REGION THROUGH THE WEEKEND...HOWEVER THE BEST CHANCE OF AFTERNOON AND EVENING THUNDERSTORMS WILL BE OVER THE MOUNTAINS OF NORTHERN AND EASTERN ARIZONA. NEAR NORMAL TEMPERATURES ARE FORECAST THE NEXT SEVEN DAYS. && .DISCUSSION... ONLY STORM ACTIVITY TODAY IN OUR FORECAST AREA WAS IN GILA COUNTY. THE ONLY STORM ACTIVITY LEFT IN ARIZONA THIS EVENING AS OF THIS WRITING IS IN FAR SOUTHEAST AND NORTHEAST PORTIONS OF THE STATE. CONSIDERABLY MORE ACTIVITY IS OVER FAR SOUTHWEST NEW MEXICO ASSOCIATED WITH AN UPPER LOW. THE 00Z PSR SOUNDING CAME IN WITH A CAPPING INVERSION NEAR 740 MB BUT THE 03Z SOUNDING SHOWED IT HAD BEEN DECREASED QUITE A BIT IN ASSOCIATION WITH A LAYER OF NORTHEASTERLY WINDS AROUND THAT LEVEL. HOWEVER...THERE WAS STILL SOME CIN TO OVERCOME AND NOT A LOT OF CAPE. THE HRRR MODEL DEPICTS THE NEW MEXICO ACTIVITY TO ADVECT INTO SOUTHEAST ARIZONA LATER TONIGHT AND CONTINUE INTO THE MORNING BUT NOT REACH OUR FORECAST AREA. THUS WILL HOLD ON TO ONLY A SLIVER OF SLIGHT CHANCE POPS OVER EASTERN GILA COUNTY OVERNIGHT. THE 21Z SREF INDICATES PRECIP PROBABILITIES FOR WEDNESDAY WILL EXTEND A BIT FURTHER WEST THAN THEY DID TODAY. THE 00Z GFS AND NAM INDICATE BETTER QPF COVERAGE OVER SOUTHEAST ARIZONA WEDNESDAY...SPILLING INTO SOUTH-CENTRAL ARIZONA...AS THE UPPER LOW NEAR THE NEW MEXICO TRIES TO MOVE INTO ARIZONA. HOWEVER...THEY ALSO SHOW IT NOT GETTING VERY FAR BEING BLOCKED BY AN UPPER ANTICYCLONE DEVELOPING OVER THE MOHAVE DESERT REGION. CONSERVATIVE POPS FOR WEDNESDAY STILL LOOK GOOD. NO CHANGES TO THE FORECAST AT THIS TIME. && .PREVIOUS DISCUSSION ISSUED 245 PM... THIS EVENING... REGIONAL WEATHER BALLOON SOUNDINGS SHOWED THE DEEPEST MONSOON MOISTURE CONTINUED TO RESIDE OVER ALL OF SOUTHERN CA...AND ACROSS THE SOUTHWEST HALF OF AZ. IT WAS DRIER OVER NORTHEAST AZ AND NW MEW MEXICO. FOR EXAMPLE...THE 12Z MON SAN DIEGO...YUMA...PHOENIX...LAS VEGAS...AND TUCSON SOUNDINGS ALL SHOWED BETWEEN 1.50 AND 1.78 INCHES OF PRECIP WATER...WHILE FLAGSTAFF WAS 0.94 AND ALBUQUERQUE 0.75. AND...THE LOW LEVEL MONSOON MOISTURE GRADIENT /OR THETA-E GRADIENT/ WAS RATHER TIGHT BETWEEN PHOENIX AND FLAGSTAFF SIGNALING THAT IF STORMS DEVELOPED OFF THE MOGOLLON RIM...THEY HAVE THE POTENTIAL TO BACK-BUILD TOWARD THE MOISTURE SOURCE...ON OUTFLOWS...TOWARD THE CENTRAL DESERTS INCLUDING PHOENIX...WICKENBURG...AND CASA GRANDE THIS EVENING. IN THE UPPER LEVELS...THE MEXICAN INVERTED TROF WE HAVE BEEN TRACKING FROM THE BIG BEND TEXAS AREA SUNDAY AFTERNOON...HAS WEAKENED CONSIDERABLY AND WAS LOCATED IN SOUTHWEST NEW MEXICO THIS MORNING. WEAK UPPER LEVEL SOUTHEASTERLY WINDS AROUND THIS SOUTHWEST NEW MEXICO LOW PRESSURE SYSTEM...AOA 300 MB...CONFLICTING WITH SOUTHWESTERLY FLOW ALOFT OVER SOUTHWEST AZ...HAS FORMED A NORTH/SOUTH DEFORMATION ZONE/AXIS OF DILATATION JUST INSIDE THE EASTERN AZ BORDER. PROGS SHOW THIS DEFORMATION ZONE WILL BECOME ENHANCED SOMEWHAT IN EASTERN AZ THIS EVENING. STABLE UPPER LEVEL SOUTHWESTERLY WINDS INCREASE OVER SOUTHERN CA AND SOUTHWEST AZ FOR A NEAR ZERO CHANCE OF STORMS TONIGHT. WEDNESDAY... JUST ABOUT DITTO ON WEDNESDAY AS UPPER LEVEL WINDS AND PLENTY OF MONSOON MOISTURE FAVOR AFTERNOON/EVENING STORM DEVELOPMENT OVER EAST CENTRAL AND SOUTHEAST AZ. AGAIN...THE POTENTIAL FOR CONVECTIVE OUTFLOWS INTO THE CENTRAL DESERTS FROM PHOENIX TO CASA GRANDE WILL BE THE CATALYST FOR A THREAT OF WEDNESDAY EVENING STORMS. SOUTHEAST CA AND SOUTHWEST AZ REMAIN DRY. ON ANOTHER NOTE...THE AIRMASS OVER THE REGION NEVER REALLY DRIES OUT. MONSOON MOISTURE THINS A BIT WED AND THU...BUT GETS REPLENISHED FROM THE SOUTHEAST DIRECTION FRIDAY AND SATURDAY. THURSDAY THROUGH SUNDAY... CO-LOCATED 300 AND 250 MB HIGH CENTERS GYRATE AROUND SOUTHEAST AZ THROUGH THIS PERIOD. HARD TO TIME FAVORABLE UPPER LEVEL WINDS TO SUPPORT TALL CONVECTION WILL DEVELOP OVER SOUTH CENTRAL AND SOUTHEAST AZ. THEREFORE THE CHANCE OF STORMS INCREASE OVER SOUTH CENTRAL THIS PERIOD. A SLIGHT CHANCE OF AFTERNOON AND EVENING THUNDERSTORMS MAY DEVELOP IN SOUTHWEST AZ...ESPECIALLY IN YUMA AND LA PAZ COUNTIES AROUND THE KOFA MOUNTAINS...AND NEAR QUARTZSITE AND WENDEN. MONDAY AND TUESDAY... MONSOON MOISTURE STARTS TO THIN THIS PERIOD...AND A LARGE 300/250 MB ANTICYCLONE CENTERED IN SOUTHWEST NEW MEXICO WILL HELP TO STABILIZE MOST OF OUR FORECAST AREA...INCLUDING SOUTHEAST CA...SOUTHWEST AZ...AND PARTS OF SOUTH CENTRAL AZ. IN OTHERWISE A DRIER AND MORE STABLE ATMOSPHERE WILL SPREAD INTO THE FORECAST FROM THE WEST. && .AVIATION... SOUTH-CENTRAL ARIZONA...INCLUDING KPHX...KIWA AND KSDL... THUNDERSTORMS OVER GILA AND GRAHAM COUNTIES EAST OF PHOENIX AS OF 00Z WILL STRUGGLE TO SURVIVE OVER THE LOWER ELEVATIONS AND THUS DID NOT MENTION TSTMS IN THE 00Z TAFS. OUTFLOW DRIVEN WIND SHIFTS FROM DISTANT STORMS ARE MORE LIKELY BUT CONFIDENCE NOT HIGH ENOUGH TO DEPICT IN THE TAFS AS OF THIS WRITING. OTHERWISE...EXPECT WESTERLY SURFACE WINDS THIS EVENING...OCCASIONALLY GUSTING 15-18 KTS...BEFORE TRANSITIONING TO TYPICAL OVERNIGHT DRAINAGE PATTERNS FAVORING EASTERLY DIRECTIONS. SOUTHEAST CA AND SOUTHWEST AZ...INCLUDING KIPL AND KBLH... EXPECT FEW TO SCT CU DECREASING DURING THE EVENING...OTHERWISE SKIES WILL REMAIN MOSTLY CLEAR. WINDS GENERALLY LESS THAN 10KTS FROM THE SOUTH OVER THE LOWER COLORADO RIVER VALLEY AND WEST OVER THE IMPERIAL VALLEY. AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS. && .FIRE WEATHER... FRIDAY THROUGH TUESDAY... MOISTENING TREND WILL TAKE PLACE FRIDAY AS ANOTHER LOW PRESSURE SYSTEM MOVES INTO SOUTHERN ARIZONA. SHOWERS AND THUNDERSTORMS WILL INCREASE IN COVERAGE...PARTICULARLY ACROSS THE EASTERN ARIZONA HIGHER TERRAIN INCLUDING SOUTHERN GILA COUNTY...BUT ALSO INTO THE LOWER DESERTS OF SOUTH-CENTRAL ARIZONA. SOUTHWESTERLY FLOW WILL BRING SOMEWHAT DRIER CONDITIONS TO THE REGION DURING THE LATE WEEKEND AND INTO NEXT WEEK. A WARMING TREND IS EXPECTED AS WELL...WITH A RETURN TO NEAR NORMAL TEMPERATURES. $$ && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...NONE. CA...NONE. && $$ VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX DISCUSSION...AJ PREVIOUS DISCUSSION...VASQUEZ AVIATION...AJ FIRE WEATHER...HIRSCH
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
405 AM EDT WED JUL 24 2013 .SYNOPSIS... 08Z WATER VAPOR AND H4 RAP ANALYSIS SHOW AN UPPER LEVEL PATTERN ACROSS THE CONUS CONSISTING OF BROAD RIDGING OVER THE INTER-MOUNTAIN WEST FOLLOWED BY DOWNSTREAM LONGWAVE TROUGHING OVER THE EASTERN HALF OF THE NATION. OUR FORECAST AREA RESIDES WITHIN A ZONE OF DEEP LAYER WEST TO NORTHWEST FLOW ON THE SOUTHERN PERIPHERY OF THE EASTERN CONUS TROUGH. GFS/NAM/ECMWF ALL INITIALIZED A WEAK SHORTWAVE IMPULSE DROPPING SOUTHEASTWARD INTO THE BASE OF THE TROUGH ACROSS SOUTHERN AL/GA/NORTH FLORIDA EARLY THIS MORNING. THIS IMPULSE HELPED FUEL A DECENT BOWING SEGMENT OF CONVECTION TUESDAY EVENING THAT DROPPED SOUTH THROUGH SOUTHERN AL/FL PANHANDLE. THIS MCS HAS SINCE DISSIPATED...HOWEVER THE SYNOPTIC SUPPORT FROM THIS FEATURE PASSING ACROSS THE NORTHEAST GULF/NORTHERN FLORIDA LATER THIS MORNING SHOULD HELP TO RE-IGNITE AT LEAST A SCATTERING OF SHOWERS/STORMS MOVING ONSHORE FOR THE NATURE COAST ZONES. MORE ON THIS IN THE SHORT TERM SECTION BELOW. AT THE SURFACE... FORECAST AREA RESIDES WITHIN A ZONE OF LOW LEVEL WESTERLY FLOW BETWEEN THE SUBTROPICAL RIDGE AXIS OVER FAR SOUTH FLORIDA...AND A WEAK SURFACE TROUGH EXTENDING FROM THE GA COAST TO THE FL BIG BEND REGION. REGIONAL RADARS HAVE QUIETED DOWN OVER THE PENINSULA IN THE PAST SEVERAL HOURS...HOWEVER EVIDENCE OF THE NEXT UPPER LEVEL IMPULSE MENTIONED ABOVE CAN BE SEEN WITH A SECONDARY CLUSTER OF CONVECTION DROPPING SOUTH FROM SOUTHERN AL/GA TOWARD THE I-10 CORRIDOR/TALLAHASSEE AREA. THE SUPPORT FOR ADDITIONAL SHOWER/STORM DEVELOPMENT WILL BE ARRIVING LATER THIS MORNING OVER OUR NORTHERN ZONES/NE GULF OF MEXICO AND WILL JUST HAVE TO WAIT AND SEE HOW MUCH RE-DEVELOPMENT WE ACTUALLY GET INTO OUR NATURE COAST ZONES. && .SHORT TERM (TODAY THROUGH FRIDAY)... TODAY...MAIN PLAYER IN THE FORECAST WILL THE PASSAGE OF A SHORTWAVE IMPULSE ACROSS THE NORTHERN THIRD OF THE STATE. BASED ON NWP ENSEMBLE TIMING...WOULD APPEAR THIS IMPULSE WILL HAVE THE MOST INFLUENCE/SYNOPTIC FORCING OVER OUR NORTHERN ZONES (MAINLY NORTH OF I-4) AND MAINLY DURING THE MORNING/EARLY AFTERNOON HOURS. LATER IN THE DAY...LOOKS AS THOSE THE PVA AXIS WILL SHIFT OVER TOWARD THE EAST COAST OF THE PENINSULA AND EVEN LEAVE PARTS OF THE NATURE COAST WITHIN A ZONE OF NVA/WEAK SUBSIDENCE BY THE TIME THE EVENING ARRIVES. TOUGH CALL ON JUST HOW MUCH CONVECTION THIS IMPULSE WILL RESULT IN DURING THE NEXT 12 HOURS OR SO FOR OUR AREA. THE BEST RAIN CHANCES AND POTENTIAL FOR ORGANIZED CONVECTION WILL BE NORTH OF THE I-4 CORRIDOR...HOWEVER ANY CONVECTIVE COLD POOLS PROPAGATING SOUTHWARD FROM THIS ACTIVITY WOULD BE ENOUGH TO SUPPORT SHOWER/STORMS DOWN INTO THE TAMPA BAY AREA AS WELL...ESPECIALLY LATE MORNING/EARLY AFTERNOON. FURTHER SOUTH FROM THE TAMPA BAY AREA...RAIN CHANCES FOR THE MORNING HOURS/EARLY AFTERNOON WILL DECREASE QUICKLY. SECOND HALF OF THE AFTERNOON AND INTO THE EVENING HOURS...THE WESTERLY FLOW SHOULD PUSH ANY FEEBLE SEA-BREEZE WELL INLAND. THIS INLAND PENETRATION ALONG WITH BETTER SYNOPTIC FORCING TO THE EAST SHOULD RESULT IN BEST RAIN CHANCES SHIFTING EAST OF THE I-75 CORRIDOR. AGAIN...THIS IS NOT A VERY DEFINED OR CLIMATOLOGICAL PATTERN FOR LATE JULY...AND THE RESULTING FORECAST CONFIDENCE IS A BIT LOWER THAN AVERAGE. FINALLY...DEVELOPING MODERATE ONSHORE FLOW OVER THE NORTHEAST GULF OF MEXICO IS EXPECTED TO RESULT IN DEVELOPING CHOPPY AND BREAKING SURF LATER TONIGHT INTO TONIGHT ALONG THE BEACHES OF PINELLAS... HILLSBOROUGH...MANATEE...AND SARASOTA COUNTIES. THESE CONDITIONS WILL RESULT IN AN ELEVATED MODERATE RISK OF RIP CURRENTS ALONG THE BEACHES OF THESE COUNTIES INTO TONIGHT. TONIGHT... LINGERING INLAND SHOWERS AND STORMS WILL FADE BY LATE EVENING WITH THE LOSS OF DIURNAL HEATING AND THE PASSAGE OF THE SHORTWAVE OFF THE FLORIDA EAST COAST. ANY BRIEF WEAK NVA/SUBSIDENCE WILL ALSO EXIT BY THE SECOND HALF OF THE NIGHT LEAVING THE REGION UNDER A BROAD AREA OF CYCLONIC FLOW AT THE BASE OF THE EASTERN CONUS TROUGH. WESTERLY LOW LEVEL FLOW IS CLIMATOLOGICALLY FAVORABLE FOR LATE NIGHT NOCTURNAL SHOWERS DEVELOPING OVER THE NE GULF AND MOVING BACK TOWARD THE COAST AROUND DAWN. ADD THE CYCLONIC FLOW ALOFT AND IT SEEMS A GOOD BET THAT THIS SCT ACTIVITY WILL INDEED DEVELOP. WILL BRING SLIGHT CHANCE 20% POPS BACK TO THE TAMPA BAY COAST AFTER 09Z...AND CHANCE 30-40% POPS FURTHER NORTH ALONG THE NATURE COAST IN CLOSEST PROXIMITY TO THE LOW LEVEL FOCUS OF A SURFACE TROUGH AXIS NEAR THE I-10 CORRIDOR. THURSDAY/FRIDAY...UPPER TROUGH IS STILL IN PLACE FOR THURSDAY AND THEN BEGINS TO DE-AMPLIFY ON FRIDAY LEAVING OUR REGION WITHIN A NEUTRAL UPPER LEVEL PATTERN TO CLOSE OUT THE SHORT-TERM FORECAST PERIOD. AT THE SURFACE...THE SUBTROPICAL RIDGE AXIS HOLDING IN PLACE TO OUR SOUTH WILL KEEP A GENERALLY LIGHT WESTERLY FLOW OFF THE EASTERN GULF OF MEXICO. FORECAST WILL FEATURE A NEAR CLIMO PATTERN FOR THIS FLOW WITH BEST RAIN CHANCES FOR SCT SHOWERS/STORMS ALONG THE COAST IN THE MORNING/EARLY AFTERNOON...AND THEN CONVECTION SHIFTING MAINLY INLAND FROM I-75 AND BECOMING FOR ROBUST FOR THE LATER PORTION OF THE DAY. && .LONG TERM (SATURDAY THROUGH NEXT TUESDAY)... THROUGH THE WEEKEND AN UPPER TROUGH DOMINATES THE EASTERN U.S. WITH A COUPLE OF EMBEDDED SHORT WAVE TROUGHS ROTATING THROUGH IT...PUSHING A COUPLE OF FRONTAL BOUNDARIES INTO THE SE U.S. HOWEVER THESE BOUNDARIES ARE EXPECTED TO STALL ALONG THE GA/FL BORDER AS THE SUBTROPICAL RIDGE AXIS RESIDES OVER OR JUST SOUTH OF SOUTHERN FL. LIGHT WESTERLY FLOW DOMINATES FOR THE WEEKEND WITH ISOLATED NOCTURNAL SHOWERS OR STORMS THAT PUSH ONSHORE IN THE MORNINGS THEN OVER THE INTERIOR IN THE AFTERNOONS AS THEY INCREASE IN COVERAGE. FOR MON AND TUE THE UPPER TROUGHINESS BEGINS TO WEAKEN AND LIFT NORTH AS THE SUBTROPICAL RIDGE BUILDS IN OVER THE GULF AND SHIFTS NORTHWARD OVER THE STATE. THIS WILL GRADUALLY BACK FLOW TO SOUTHERLY THEN SOUTHEASTERLY BUT RELAXED ENOUGH TO ALLOW AFTERNOON SEA BREEZES TO FORM. THIS RESULTS IN A PATTERN OF LATE MORNING TO AFTERNOON SHOWERS AND STORMS WITH COASTAL LOCATIONS SLIGHTLY FAVORED FOR THE HIGHEST COVERAGE. && .AVIATION... MAINLY VFR. THERE IS SOME PATCHY BR BUT THIS IS NOT EXPECTED TO IMPACT THE TAF TERMINALS. NOCTURNAL GULF SHOWERS MAY REACH TPA/PIE/SRQ LATER TONIGHT. SCT TSRA NEAR TPA/PIE/LAL/SRQ THROUGH THE AFTERNOON. LIGHT VARIABLE OR SOUTHWESTERLY WINDS BECOME WESTERLY AND INCREASE DURING THE DAY...AND WILL BE GUSTY AT TIMES. && .MARINE... MODERATE WESTERLY FLOW BETWEEN THE SUBTROPICAL RIDGE TO OUR SOUTH AND A SURFACE TROUGH TO OUR NORTH WILL DEVELOP THIS MORNING AND LINGER INTO THURSDAY MORNING BEFORE THE GRADIENT BEGINS TO WEAKEN LATER THURSDAY INTO THE LATER PORTION OF THE WEEK. WINDS MAY AT TIMES APPROACH CAUTIONARY LEVELS LATER TODAY AND TONIGHT... ESPECIALLY NORTH OF ENGLEWOOD. THE SUBTROPICAL RIDGE AXIS BUILDS BACK NORTH ACROSS THE EASTERN GULF OF MEXICO FOR THE UPCOMING WEEKEND AND EARLY PORTION NEXT WEEK HELPING TO KEEP WINDS AND SEAS WELL BELOW CAUTIONARY LEVELS. && .FIRE WEATHER... RELATIVE HUMIDITY VALUES ARE FORECAST TO REMAIN WELL ABOVE CRITICAL LEVELS THROUGH THE NEXT SEVERAL DAY. HOWEVER...ELEVATED FLOW ALOFT WILL RESULT IN HIGH DISPERSION INDICES LATER TODAY AND AGAIN ON THURSDAY && .PRELIMINARY POINT TEMPS/POPS... TPA 89 78 91 78 / 40 20 30 20 FMY 91 77 90 76 / 20 10 20 20 GIF 91 74 93 74 / 40 20 50 20 SRQ 90 78 90 78 / 30 20 30 30 BKV 91 74 92 72 / 50 30 50 30 SPG 91 80 90 79 / 30 20 30 30 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...RIP CURRENT RISK FROM NOON EDT TODAY THROUGH LATE TONIGHT FOR HILLSBOROUGH-MANATEE-PINELLAS-SARASOTA. GULF WATERS...NONE. && $$ SYNOPSIS/SHORT TERM/MARINE/FIRE WX...MROCZKA LONG TERM/AVIATION...RUDE
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
400 AM EDT WED JUL 24 2013 .DISCUSSION... ...RAIN CHANCES SLIGHTLY ABOVE NORMAL CHANCES THROUGH THIS WEEKEND... TODAY-TONIGHT... DEEP LYR TROF OVER THE ERN SEABOARD HAS AMPLIFIED WITH THE H100-H85 AXIS EXTENDING ALMOST TO THE FL BIG BEND. W/SWRLY FLOW ALOFT HAS INCREASED STEADILY SINCE MIDNIGHT WITH LCL WIND PROFILES SHOWING A SOLID 15-20KTS THRU 10KFT. LATEST SFC OBS SHOW A 4-5MB SFC PGRAD BTWN KMFL-KJAX...TIGHT ENOUGH TO SUPPORT SFC WNDS OF THE SAME MAGNITUDE AFT SUNRISE ACCORDING TO LCL GEOSTROPHIC APPROXIMATION TABLE. RUC ANALYSIS: A RESPECTABLE POCKET OF H85-H50 VORTICITY OVER THE DEEP SOUTH POISED TO ROTATE ACRS THE NORTH AND CENTRAL FL PENINSULA OVER THE NEXT 24HRS. MID LVL THERMAL PROFILE IS A MIXED BAG WITH H85-H50 LAPSE RATES BTWN 6.0-6.5C/KM BUT WITH H50 TEMPS BTWN -6C AND -7C. LITTLE IN THE WAY OF UPR LVL SUPPORT AS THE H30-H20 WIND FIELD OVER THE ERN GOMEX/W ATLC ARE LARGELY N/NW BLO 20KTS. EVENING RAOB SOUNDINGS SHOW PLENTIFUL MOISTURE WITH PWAT VALUES BTWN 1.9"-2.0". HOWEVER...THE KTBW SOUNDING SHOWS MUCH OF IT ABV THE H60 LVL WITH DEW POINT DEPRESSIONS THRU THE H90-H60 LYR AOA 5C... INDICATIVE OF A LACK OF LOW/MID LVL MOISTURE. FURTHERMORE...UPSTREAM MOISTURE OVER THE GOMEX IS LACKING WITH RUC ANALYSIS SHOWING H100-H70 MEAN RH VALUES LARGELY AOB 70PCT. NEITHER THE LACK OF MOISTURE NOR THE TEPID THERMODYNAMIC PROFILE SUPPORTS HIGH COVERAGE POPS...ESPECIALLY GIVEN THE EAST COAST SEA BREEZE IS UNLIKELY TO FORM IN SUCH A STRONG WIND FIELD. HOWEVER...THE VORT MAX OVER THE DEEP SOUTH IS THE WILD CARD AND SHOULD GENERATE ENOUGH MID LVL SUPPORT TO KICK PRECIP CHANCES TO 50PCT ALONG AND N OF I-4. PRECIP WILL DIMINISH TO 30PCT ARND LAKE OKEECHOBEE DUE TO LOWER MOISTURE AND WEAKER INFLUENCE WRT THE H50 VORT MAX. LINGERING PRECIP THRU LATE EVNG BUT ENDING BY MIDNIGHT AS THE VORT MOVES OFFSHORE. WRLY WINDS AND NO SEABREEZE WILL GENERATE MAX TEMPS IN THE L90S OVER THE COASTAL COUNTIES...NEAR 90F OVER THE INTERIOR. LIGHT WRLY FLOW OVERNIGHT WILL PREVENT DECOUPLING...KEEPING MIN TEMPS IN THE M70S. THU-SAT...LARGER SCALE PATTERN SHOWS THE LARGE/BROAD EASTERN CONUS SLOWLY FILLING...WITH THE AXIS REDEVELOPING A LITTLE FARTHER WEST BY THIS WEEKEND. THESE SUBTLE CHANGES ALOFT PORTEND SUBTLE/SLIGHT CHANGES AT THE SURFACE AS WELL. ON THU...WEAK SURFACE WAVE/LOW NEAR THE SE ATLC SEABOARD SCOOTS OFF TO THE NE ALONG WITH PARENT SHORT WAVE TROUGH. FROM LATER FRI ONWARD...SLIGHT BACKING AND WEAKENING OF THE SURFACE FLOW TAKES PLACE AS THE SURFACE RIDGE ATTEMPTS TO BUILD WEST TWD FL. MOISTURE REMAINS SUFFICIENTLY DEEP WITH PWATS REMAINING SLIGHTLY ABOVE NORMAL BY A TENTH OR TWO...AND HENCE POPS WILL DO SO AS WELL - GENERALLY 40-50 PERCENT). STORM STRENGTH LOOKS PRETTY TYPICAL...MOSTLY HEAVY RAIN AND LIGHTNING BEING THE MAIN THREATS... WITH SOME STRONGER (MAINLY SUB-SEVERE) STORMS POSSIBLE. TEMPS LOOK PRETTY CLOSE TO CLIMO...MAYBE A TAD ABOVE NEAR THE COAST. OVERALL... SHAVED ABOUT 1-2F FROM MAV MAXES OVER THE INTERIOR. SUN-WED...DAY 5-8 CONTINUE THE TREND ESTABLISHED IN THE SHORT RANGE. NAMELY...CONTINUE GRADUALLY FILLING OF THE TROUGH TO THE NORTH WHILST DEEP LAYER MEAN (DLM) RIDGING CONTINUES TO BUILD WESTWARD FROM THE ATLANTIC INTO FLORIDA. THIS SHOULD SPELL A SLIGHT DRYING TREND... WITH CONTINUED BACKING OF SURFACE WINDS MORE TWD THE SE...HENCE LCL POP DISTRIBUTION WILL FAVOR THE CENTRAL-WESTERN PENINSULA. LOOKING AT POPS DROPPING BACK MORE TO 30-40 (10 PCT HIGHER OVER THE INTERIOR) EARLY NEXT WEEK. TEMPS REMAIN FAIRLY CLOSE TO CLIMO. && .AVIATION...THRU 24/14Z...VFR ALL SITES. BTWN 24/14Z-24/16Z...W/SW SFC WNDS INCRSG TO 12-16KTS WITH G18-24KTS. BTWN 24/16Z-24/24Z...SCT MVFR SHRAS/IFR TSRAS DVLPG AND MVG E ARND 15KTS...BRIEF LIFR CONDS N OF KTIX-KISM IN +TSRA BTWN 14/18Z-24/22Z. BTWN 25/00Z-25/03Z...SCT MVFR SHRAS/ISOLD IFR TSRAS COASTAL SITES N OF KVRB...ISOLD SHRAS/TSRA INTERIOR AND S OF KVRB. AFT 25/03Z...VFR ALL SITES. && .MARINE...TODAY-TONIGHT...DEEP TROF OVER THE ERN SEABOARD EXTENDING INTO N FL WILL GENERATE A MODERATE WRLY BREEZE WITH OCNL SFC GUSTS ABV 20KTS. OFFSHORE WIND COMPONENT WILL GENERATE SHORT PD CHOP NEARSHORE WITH DOMINANT WAVE PDS EXPECTED TO SHORTEN TO AOB 5 SEC.. .OFFSHORE WAVE PDS 6-8SEC. SCT TSRAS MOVING OFFSHORE THIS AFTN. THU-SUN...ATLC SURFACE RIDGE WILL REMAIN SOUTH/EAST OF THE CWA THROUGH EARLY FRI...BEFORE GRADUALLY BUILDING NORTH/WEST TOWARD THE ECFL MAOR. SEAS WILL BE IN THE 2-3FT RANGE FOR THE MOST PART ...INCREASING SLIGHTLY OFFSHORE BY SUNDAY AS SRLY FLOW FRESHENS SOME. && .PRELIMINARY POINT TEMPS/POPS... DAB 90 75 92 75 / 50 30 50 40 MCO 89 75 93 75 / 50 20 50 30 MLB 91 74 91 73 / 40 30 50 40 VRB 91 74 89 73 / 40 20 50 40 LEE 89 75 92 75 / 50 20 50 30 SFB 90 75 94 76 / 50 30 50 30 ORL 89 75 93 76 / 50 20 50 30 FPR 91 74 90 72 / 30 20 50 30 && .MLB WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. && $$ SHORT TERM/AVIATION...BRAGAW LONG TERM/IMPACT WX....CRISTALDI
AREA FORECAST DISCUSSION...UPDATED
NWS MIAMI FL
137 AM EDT WED JUL 24 2013 .AVIATION... THE WEATHER SHOULD REMAIN DRY THROUGH THE MORNING HOURS AT ALL OF THE TAF SITES OF SOUTH FLORIDA. FOR THE AFTERNOON HOURS TODAY...THERE COULD BE SOME SHOWERS AND EVEN A FEW STORMS OVER THE EAST COAST METRO AREAS MAINLY BETWEEN 19Z AND 23Z. SO HAVE PUT IN VCSH FOR THE EAST COAST TAF SITES FROM 17Z UNTIL 03Z...WITH EVEN A VCTS BETWEEN 20Z AND 01Z. FOR TAPF TAF SITE...THE BEST COVERAGE OF ANY SHOWERS WILL IN THE AFTERNOON HOURS. THE CEILING AND VIS WILL ALSO REMAIN IN THE VFR CONDITIONS DUE TO THE UNKNOWN TIMING OF THE SHOWERS AND THUNDERSTORMS. THE WINDS WILL REMAIN IN A SOUTHWEST DIRECTION AT 5 KNOTS OR LESS EARLY THIS MORNING BEFORE INCREASING TO AROUND 10 KNOTS BY THIS AFTERNOON. && .AVIATION...54/BNB .PREV DISCUSSION... /ISSUED 912 PM EDT TUE JUL 23 2013/ UPDATE... A FEW SHOWERS/TSTMS ARE LINGERING OVER AND NEAR THE WESTERN SUBURBS OF SE FLORIDA THIS EVENING AS THE LAST OF TODAY`S CONVECTION MOVES EAST. EXPECT THIS ACTIVITY TO EITHER DISSIPATE OR MOVE OFFSHORE BY MIDNIGHT AT THE LATEST, WITH MOSTLY CLEAR AND DRY CONDITIONS EXPECTED FOR THE OVERNIGHT HOURS. ZONES WILL BE UPDATED BEFORE 11 PM TO REFLECT THIS, UNLESS SHOWERS/TSTMS LINGER LONGER THAN EXPECTED. HYDROLOGY UPDATE...FLOOD WARNING FOR FISHEATING CREEK WILL BE REEVALUATED WITH NEW RFC GUIDANCE WITHIN THE HOUR TO DETERMINE IF THE WARNING NEEDS TO BE CONTINUED. CREEK LEVELS HAVE BEEN FALLING SLIGHTLY SINCE THIS MORNING AND WITH NOT MUCH RAIN IN THE AREA TODAY, THE CREEK MAY NOT REACH THE FORECAST FLOOD STAGE OF 7 FEET. && MOLLEDA PREV DISCUSSION... /ISSUED 750 PM EDT TUE JUL 23 2013/ AVIATION... CONVECTION ACROSS INTERIOR SHOULD CONTINUE TO BE DRIVEN BY LINGERING OUTFLOW BOUNDARIES ACROSS INTERIOR PALM BEACH...BROWARD AND MIAMI-DADE COUNTIES FOR THE NEXT FEW HOURS BEFORE DISSIPATING. OTHERWISE...SOUTHEASTERLY FLOW SHOULD VEER MORE SOUTHWESTERLY OVERNIGHT AND REMAIN LIGHT. SOUTHWESTERLY FLOW SHOULD PREVAIL THROUGH THE DAY TOMORROW WHICH SHOULD FOCUS ANY CONVECTIVE DEVELOPMENT ALONG THE INTERIOR AND EAST COASTAL AREAS. && PREV DISCUSSION... /ISSUED 215 PM EDT TUE JUL 23 2013/ SHORT TERM (TONIGHT-THURSDAY NIGHT)... A STRONG SUBTROPICAL DEEP LAYER RIDGE CURRENTLY LOCATED ACROSS SOUTH FLORIDA AND THIS SUPPRESSING THE CONVECTION. THE 12Z MFL SOUNDING SHOWED THE LOWEST LAYERS OF THE ATMOSPHERE HAD DESTABILIZED SUBSTANTIALLY FROM 24 HOURS AGO SO CU DEVELOPED EARLIER WHICH HAS LEAD TO EARLIER SHOWER DEVELOPMENT TOO ALONG WITH A FEW THUNDERSTORMS. A SEA BREEZE LINE OF CONVECTION DEVELOPED RIGHT ALONG THE COAST OF SOUTHERN BROWARD AND IT APPEARS THAT SOME ADDITIONAL CONVERGENCE SET UP OTHER THAN JUST THE SEA BREEZE. LOOKING AT VISIBLE SATELLITE IMAGES REVEALS A CONVERGENT BOUNDARY ASSOCIATED WITH AN OUTFLOW/LAND BREEZE OFF THE EAST COAST WITH THIS BAND EXTENDING WELL OUT INTO THE ATLANTIC. OUTSIDE OF THIS, THERE IS ALSO A MID LEVEL TROUGH THAT IS DEEPENING OVER THE EASTERN STATES WITH FORECAST SOUNDINGS INDICATING THE RIDGE WOULD BEGIN TO SHIFT SOUTH THROUGH THIS AFTERNOON AND THIS APPEARS TO BE OCCURRING WITH LOW TOPPED CONVECTION ALREADY DRIFTING TO THE EAST. HOWEVER, AS THE DAY PROGRESSES AND DIURNAL HEATING CAN DESTABILIZE A DEEPER PORTION OF THE ATMOSPHERE THE STEERING FLOW IS STILL VERY WEAK SO STORM MOTION IS STILL EXPECTED TO BE SLOW AND POSSIBLY ERRATIC ALTHOUGH THERE COULD BE A DRIFT TOWARDS THE EAST. SOME OF THE SHORT RANGE HIGH RESOLUTION MODELS SUCH AS THE HRRR ARE SHOWING MORE ROBUST CONVECTION FORMING OVER THE INTERIOR AROUND 17-18Z (ALTHOUGH THIS NOT OCCURRING AS OF 1815Z) AND THEN SLOWLY MOVING TOWARDS THE EAST BUT THEN AS THE HEATING CYCLE IS CUT OFF WITH A LOWER SUN ANGLE, THE CONVECTION NEVER MAKES IT QUITE TO THE EAST COAST AND THIS APPEARS REASONABLE GIVEN THE ABOVE REASONING. THE RIDGE WILL CONTINUE TO SHIFT SOUTH TONIGHT AND BE OVER THE FLORIDA STRAITS INCLUDING THE KEYS AS THE TROUGH CONTINUES TO DEEPEN. THIS WILL ALLOW FOR A DEEP WESTERLY FLOW TO BECOME ESTABLISHED ON WEDNESDAY AND THURSDAY WITH FORECASTING SOUNDINGS SHOWING A STORM MOTION OF AROUND 5-7 MPH ON WEDNESDAY AND NEAR 10 MPH ON THURSDAY. NONE OF THE GLOBAL MODELS HOWEVER INDICATE AN ABUNDANCE OF DEEP LAYER AVAILABLE MOISTURE NOR INSTABILITY SO WIDESPREAD CONVECTION AT THIS TIME IS NOT EXPECTED. THE NAM, GFS AND ECMWF ALL SHOW PWAT IN THIS TIME FRAME TO BE 1.5-1.7 INCHES WHICH IS CLOSE TO OR SLIGHTLY BELOW THE AVERAGE FOR MID TO LATE JULY. BUT THE SCATTERED STORMS THAT DO DEVELOP IN THIS PATTERN WILL FAVOR THE INTERIOR AND EAST COAST METRO AREAS. LONG TERM (FRIDAY-TUESDAY)... NOT MUCH CHANGE IS FORESEEN LOOKING TOWARDS THE END OF THE WEEK INTO SATURDAY AS THE MAIN MID LEVEL TROUGH WILL REMAIN IN PLACE ACROSS THE EASTERN STATES. THIS WILL MAINTAIN THE DEEP WESTERLY FLOW ACROSS SOUTH FLORIDA WITH A FORECAST PWAT REMAINING NEAR NORMAL VALUES. NONE OF THE MODELS SHOW ANY KIND OF MOISTURE INFLUX SO AT THIS TIME, BY LATE IN THE WEEKEND AND INTO EARLY NEXT WEEK SCATTERED THUNDERSTORMS ARE EXPECTED WITH THE PATTERN AGAIN REVERTING TO MOSTLY INTERIOR AWAY FROM BOTH COASTS. MARINE... LIGHT SOUTH TO SOUTHEAST WIND WILL VEER TO A SOUTH TO SOUTHWEST DIRECTION ON WEDNESDAY AND CONTINUE THROUGH FRIDAY WITH SEAS LESS THAN 4 FEET AS THE RIDGE SHIFTS SOUTH OF THE AREA. THE RIDGE WILL THEN MOVE BACK NORTH OVER THE WEEKEND WITH A RETURN TO A LIGHT SOUTHEAST WIND. FIRE WEATHER... NO PROBLEMS OR CONCERNS WITH AMPLE TROPICAL MOISTURE. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 75 91 76 90 / 20 40 20 30 FORT LAUDERDALE 77 91 78 89 / 20 30 10 20 MIAMI 76 91 78 90 / 20 30 10 20 NAPLES 74 89 75 87 / 10 20 10 30 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ DISCUSSION/MARINE/FIRE...13/SI AVIATION/RADAR...30/KOB
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
349 AM EDT WED JUL 24 2013 .SHORT TERM /TODAY THROUGH THURSDAY/... A VERY ACTIVE WEATHER PATTERN WILL PERSIST TODAY WITH CURRENT SATELLITE WATER VAPOR IMAGERY SHOWING A SHARP UPPER SHORT WAVE OVER SE GA AND DEPARTING EASTWARD... AND A SERIES OF MORE SUBTLE DISTURBANCES EMBEDDED WITHIN THE NW FLOW ALOFT BACK TO THE WEST AND NW. REGIONAL RADAR SHOWS ISOLATED STORMS ACROSS WESTERN AL... AND THIS ACTIVITY IS ASSOCIATED WITH A WEAK DISTURBANCE PUSHING ACROSS WEST TN AND NORTH MS. FURTHER WEST... SATELLITE AND RADAR SHOW A LARGE CONVECTIVE COMPLEX ACROSS WESTERN OK/AR... AND DROPPING SSE ON A TRAJECTORY FOR THE SE TX AND LA COASTS. SURFACE ANALYSIS SHOWS A WEAK FRONTAL BOUNDARY PUSHING INTO NW TN AND EXTENDING EWD INTO VA. SHORT RANGE MODELS SHOW THESE SUBTLE DISTURBANCES TO THE WEST INTERACTING WITH A MOIST /1.8+ PW/ AND MODERATELY UNSTABLE /2000-2500 CAPE/ AIR MASS OVER GA TO PRODUCE SCATTERED SHOWERS AND THUNDERSTORMS AGAIN TODAY... MAINLY DURING THE AFTERNOON AND EVENING HOURS. THE GREATER CHANCES APPEAR TO BE ACROSS NORTH GA AHEAD OF THIS SAGGING COLD FRONT... AND AGAIN ACROSS THE WESTERN ZONES WHERE THE LOCAL WRF MODEL SHOWS ANOTHER CONVECTIVE COMPLEX DIVING SOUTHWARD ACROSS AL AND BRUSHING THE WESTERN COUNTIES DURING THE AFTERNOON. THE HRRR MODEL SHOWS MORE CONVECTION CONCENTRATED ALONG AND AHEAD OF THE APPROACHING COLD FRONT THAT PUSHES INTO NORTH GA BY EARLY-MID AFTERNOON. EXPECT THIS ACTIVITY TO PUSH SOUTH INTO CENTRAL GA DURING THE LATE AFTERNOON AND EVENING HOURS. THEREFORE... IT APPEARS STORMS COULD DEVELOP JUST ABOUT ANYWHERE TODAY. THE SLIGHTLY COOLER AND DRIER AIR ALOFT ASSOCIATED WITH THE NW FLOW CONTINUES TO SUGGEST A THREAT OF STRONG DOWNBURST WINDS AND LARGE HAIL THIS AFTERNOON AND EVENING DURING PEAK HEATING. THIS IS ALSO SUPPORTED BY SPC...WHO HAS BLANKETED A FIVE PERCENT CHANCE OF WIND AND HAIL THREAT ACROSS THE ENTIRE FORECAST AREA TODAY. ALL WARRANTS MENTION OF ISOLATED SEVERE STORMS... WITH LOCALLY HEAVY RAIN... DAMAGING WINDS AND LARGE HAIL IN THE HAZARDOUS WEATHER OUTLOOK FOR TODAY. MODELS SHOW STORM COVERAGE GREATLY DIMINISHING BEFORE MIDNIGHT WITH LOSS OF DAYTIME HEATING. SHORT RANGE MODELS AGREE ON SAGGING THE FRONT ACROSS NORTH GA OVERNIGHT WITH SOME DRIER AIR SPREADING DOWN INTO THE ATLANTA AREA EARLY ON THURSDAY. THIS SHOULD HOLD CONVECTION DOWN TO ISOLATED OR LESS FOR MUCH OF NORTH GA TO INCLUDE THE ATLANTA METRO AREA ON THURSDAY. EXPECT MORE SCATTERED CONVECTION ACROSS THE FAR NE AND CENTRAL ZONES WHERE MODELS SHOW CONVECTION FIRING ALONG AND OUT AHEAD OF THE NEARLY STATIONARY FRONT. COULD SEE A FEW STRONG TO SEVERE STORMS ACROSS THE FAR SOUTH AND SE ZONES THURSDAY AFTERNOON WHERE THE FRONT AND GREATER INSTABILITIES ARE EXPECTED. AS FOR TEMPS... LEANED TOWARD A BLEND BETWEEN PERSISTENCE AND THE SLIGHTLY WARMER MAV THROUGH THE SHORT TERM. 39 .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... NO REAL CHANGES TO THE PREVIOUS MODEL TRENDS THROUGH THE EXTENDED FORECAST PERIOD. FAIRLY GOOD AGREEMENT AMONG THE MEDIUM RANGE MODELS THROUGH THE WEEKEND AS FAR AS THE LARGER SCALE FEATURES ARE CONCERNED WITH A PERSISTENT EASTERN U.S. UPPER TROUGH DOMINATING THE REGIONAL WEATHER. EXTENDED FORECAST PERIOD STARTS OUT IN A BIT OF A QUIET PERIOD AS THE MAIN UPPER TROUGH AXIS IS EAST OF THE STATE... WITH SCATTERED...MAINLY DIURNAL...CONVECTION EXPECTED THROUGH FRIDAY. WEAK NORTHWESTERLY UPPER FLOW WILL KEEP A CHANCE FOR A ROUND OR TWO OF MORE ORGANIZED CONVECTION ASSOCIATED WITH ANY WEAK RIPPLES RIDING DOWN THE BACKSIDE OF THE TROUGH...BUT NO DISTINCT SHORT WAVE IS EVIDENT IN THE MODELS AT THIS TIME. FOR THE WEEKEND...A NEW SHORT WAVE DIGS INTO THE MID-SOUTH FRIDAY NIGHT AND SWEEPS ACROSS THE REGION SATURDAY. GFS/ECMWF/CMC/NAM ARE SURPRISINGLY SIMILAR WITH THIS FEATURE SO I WILL BE BUMPING UP SATURDAY/S POPS INTO THE LIKELY RANGE. FOR NOW THE MODELS ARE ONLY SHOWING A WEAK SURFACE BOUNDARY ASSOCIATED WITH THIS FEATURE. ALTHOUGH INSTABILITY IS FORECAST TO REMAIN MODERATE AT BEST SATURDAY...SOME WEAK SHEAR IS EVIDENT SO CONVECTION MAY BE A BIT MORE ORGANIZED AND AT LEAST A SMALL INCREASE IN THE POTENTIAL FOR SEVERE STORMS WILL NEED TO BE WATCHED WITH THIS SYSTEM. WEAK SURFACE TROUGHING AND WEAK UPPER LEVEL FLOW SETTLE IN FOR THE REMAINDER OF THE EXTENDED FORECAST PERIOD. MODELS ARE SHOWING A SIGNIFICANT REDUCTION IN DEEPER LAYER MOISTURE THURSDAY NIGHT AND FRIDAY...BUT AMPLE LOW-LEVEL MOISTURE REMAINS AVAILABLE FROM THE MOIST SURFACE CONDITIONS FOR SCATTERED CONVECTION. BETTER DEEP MOISTURE ACCOMPANIES THE SYSTEM SATURDAY. A FAIRLY STRONG MOISTURE GRADIENT SETS UP FOR THE BALANCE OF THE PERIOD INTO THE MIDDLE OF NEXT WEEK WITH RELATIVELY DRY AIR ACROSS THE NORTH. HOWEVER...IN THE ABSENCE OF A STRONG UPPER RIDGE THERE SHOULD BE SUFFICIENT MOISTURE AVAILABLE FOR ISOLATED TO SCATTERED...MAINLY DIURNAL...CONVECTION AREA-WIDE EACH DAY WITH AT LEAST SLIGHTLY BETTER CHANCES ACROSS CENTRAL GEORGIA. EXCEPT FOR SATURDAY WITH THE INCREASED CLOUD COVER AND PRECIPITATION EXPECTED...TEMPERATURES ARE EXPECTED TO REMAIN AROUND SEASONAL NORMALS THROUGH THE EXTENDED FORECAST PERIOD. 20 && AVIATION... 06Z UPDATE... AREAS OF -RA HAVE DISSIPATED... BUT GROUNDS ARE WET AROUND THE AIRPORTS. AS A RESULT... LOW STRATUS AND PATCHY FOG HAS ALREADY BEGAN TO DEVELOP...WITH IFR CIGS EXPECTED TO PREVAIL AT ALL AIRPORTS EARLY THIS MORNING...AND LINGERING THROUGH AROUND 14Z. THEN VFR CIGS PREVAIL TODAY OUTSIDE OF CONVECTION. ANOTHER ROUND OF CONVECTION IS EXPECTED THIS AFTERNOON...MAINLY BETWEEN 18-24Z. LIGHT WNW WINDS THIS MORNING WILL INCREASE TO AROUND 10-12KTS BY LATE MORNING WITH OCCASIONAL HIGHER GUSTS. MODELS SHOW VFR CIGS OVERNIGHT...BUT WOULD EXPECT AT LEAST SCT010 BY 09Z THU AT MOST SITES. //ATL CONFIDENCE...06Z UPDATE... MEDIUM ON AFTERNOON CONVECTION HITTING THE AIRPORTS. HIGH ON ALL ELEMENTS. 39 && .PRELIMINARY POINT TEMPS/POPS... ATHENS 89 70 89 69 / 30 30 40 20 ATLANTA 87 71 88 71 / 40 30 20 10 BLAIRSVILLE 84 65 81 62 / 40 30 30 20 CARTERSVILLE 88 67 88 66 / 50 30 20 10 COLUMBUS 90 72 92 71 / 40 30 40 10 GAINESVILLE 87 70 87 68 / 40 30 30 20 MACON 91 71 92 71 / 40 30 40 20 ROME 88 68 89 66 / 50 30 20 10 PEACHTREE CITY 87 67 89 67 / 40 30 20 10 VIDALIA 91 73 92 72 / 30 30 50 20 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...39 LONG TERM....20 AVIATION...39
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
208 AM CDT WED JUL 24 2013 ...UPDATED LONG TERM SECTION... .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 200 PM CDT TUE JUL 23 2013 TONIGHT: NEAR TERM FORECAST CONCERN IS CONVECTION THIS AFTERNOON/EVENING. WSR- 88D AND SURFACE OBSERVATIONS SHOW A FEW BOUNDARIES ACROSS THE REGION THIS AFTERNOON. ONE IS A "COLD FRONT"/OUTFLOW BOUNDARY THIS IS ROUGHLY LOCATED FROM NESS CITY SE TO PRATT. A NONDESCRIPT DRYLINE IS THE OTHER BOUNDARY FARTHER WEST. THE INTERSECTION OF THESE TWO DENSITY GRADIENTS SHOULD BE WHERE CONVECTION INITIATES. THE MOST RECENT HRRR IS SHOWING AN ISOLATED STORM DEVELOPING JUST NORTHEAST OF DODGE CITY (MUCH LIKE YESTERDAY) AND THEN INDICATING THIS ACTIVITY DRIFTING OFF TO THE SE AS THE EARLY EVENING WEARS ON. THE NAM IS IN FAIR AGREEMENT WITH THIS SOLUTION. THE STORMS MAY BECOME SEVERE AS WELL AS 1-8 KM BULK SHEAR IS STRONGER THAN YESTERDAY...PLUS DEWPOINTS ARE STILL RUNNING FAIRLY HIGH, WHICH WILL CREATE ABOUT 1500-2000 J/KG OF SBCAPE. MODELS ALSO SHOW SOME DCAPE AS THE ATMOSPHERE BECOMES WELL MIXED. AS A RESULT, HAVE TWEAKED THE HWO WITH THE THREATS OF QUARTER SIZE HAIL, 60 MPH OUTFLOW, AND LIGHTNING AS THE MAIN CONCERNS. THIS ACTIVITY WILL CLEAR THE AREA LATER THIS EVENING AS THE FRONT SINKS SOUTHWARD. OVERNIGHT LOWS WILL BE IN THE 60S DEG F AND 70S DEG F. UPSLOPE STRATUS WILL BE POSSIBLE ON THE BACKSIDE OF THE LOW LEVEL PRESSURE PERTURBATION WITH UPSLOPE WINDS IN THE SFC-850 HPA LAYER. TOMORROW: AN UPSLOPE FLOW PATTERN IS EXPECTED TOMORROW IN THE WAKE OF THE AFOREMENTIONED BOUNDARY. MAXIMUMS WILL BE "COOLER" THAN COMPARED TO TODAY WITH VALUES IN THE UPPER 80S DEG F TO LOWER 90S DEG F. 23.12Z NAM SOLUTION IS WARMER COMPARED TO OTHER GUIDANCE, BUT THIS MIGHT BE A BIT OVERDONE. WILL USE THE ECMWF FOR NOW. OROGRAPHIC CONVECTION IS POSSIBLE IN THE UPSLOPE FLOW REGIME TOMORROW ACROSS EASTERN COLORADO. WILL CARRY SLIGHT PRECIPITATION PROBABILITY PERCENTAGE POINTS FOR FAR WEST KANSAS THROUGH 00Z TOMORROW NIGHT. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 206 AM CDT WED JUL 24 2013 AN UPPER LEVEL SHORTWAVE WILL MOVE FROM THE CENTRAL ROCKIES WEDNESDAY INTO THE CENTRAL PLAINS ON THURSDAY. THIS WILL BRING INCREASED MOISTURE TO THE MID AND UPPER LEVELS OF THE ATMOSPHERE. MEANWHILE AT THE SURFACE, A STATIONARY FRONT WILL BE LOCATED OVER THE SOUTHERN PLAINS, WITH UPSLOPE FLOW AND ABUNDANT LOW LEVEL MOISTURE ON THE COOL SIDE OF THE FRONT OVER WESTERN KANSAS. A GOOD CHANCE OF THUNDERSTORMS ARE EXPECTED ON THURSDAY INTO THURSDAY NIGHT AS THIS SYSTEM MOVES THROUGH THE AREA. OTHERWISE EXPECTED CLOUDY SKIES ON THURSDAY AND THURSDAY NIGHT. THE BEST CHANCE OF THUNDERSTORMS WILL BE THURSDAY AFTERNOON INTO THURSDAY EVENING. THIS IS ALSO WHEN A FEW STORMS COULD BECOME SEVERE WITH DAMAGING WINDS AND LARGE HAIL BEING THE MAIN CONCERN. WITH A VEERING SHEAR PROFILE AND ABUNDANT LOW LEVEL MOISTURE AN ISOLATED TORNADO WILL ALSO BE POSSIBLE. HIGHS THURSDAY ARE FORECASTED TO RANGE FROM THE LOWER 80S ACROSS WEST CENTRAL KANSAS TO AROUND 90 DEGREES ACROSS THE KS/OK BORDER. LOWS FRIDAY MORNING WILL GENERALLY BE IN THE 60S. THE AFOREMENTIONED SYSTEM SHIFTS EAST OF THE AREA ON FRIDAY WITH PRECIPITATION CHANCES CONTINUING ACROSS CENTRAL KANSAS IN THE MORNING WHICH CLEARING SKIES FROM WEST TO EAST. A BREAK IN PRECIPITATION IS EXPECTED FRIDAY AND SATURDAY, WITH CONTINUED COOL WEATHER BY THE WEEKEND, THE MID TO UPPER LEVEL FLOW WILL BECOME MORE WEST-NORTHWESTERLY AGAIN, RESULTING IN RENEWED WEAK SURFACE LEE TROUGHING AND WARM/MOIST ADVECTION INTO WESTERN KANSAS. THEREFORE, THERE ARE CHANCES OF THUNDERSTORMS AGAIN BY SATURDAY NIGHT INTO TUESDAY. HIGHS WILL GENERALLY BE IN THE MID TO UPPER 80S FRIDAY THROUGH SUNDAY WITH LOWER 90S EXPECTED MONDAY AND TUESDAY. LOWS LOOK TO DIP INTO THE 60S SATURDAY AND SUNDAY MORNING BEFORE WARMING TO AROUND 70 DEGREES SUNDAY AND MONDAY MORNING. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1223 AM CDT WED JUL 24 2013 VFR CONDITIONS WILL BE THE RULE TODAY, ALONG WITH NORTHEAST WINDS OF 11G22KT. THERE IS A CHANCE FOR A LITTLE 5SM BKN025 CONDITIONS TOWARD SUNRISE, BUT THOSE CONDITIONS SHOULD NOT LAST PAST 13Z OR SO. WINDS LATER TODAY WILL BE NORTHEAST AT 15G25KT. && .PRELIMINARY POINT TEMPS/POPS... DDC 91 69 86 67 / 10 40 60 60 GCK 90 68 86 66 / 10 50 60 50 EHA 91 66 87 65 / 20 50 50 40 LBL 93 69 89 67 / 10 40 60 50 HYS 88 68 84 66 / 10 40 50 50 P28 90 71 89 69 / 10 40 60 60 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...SUGDEN LONG TERM...HOVORKA_42 AVIATION...BURKE
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1227 AM CDT WED JUL 24 2013 ...UPDATED FOR THE 06Z TAFS AND AVIATION DISCUSSION... .SYNOPSIS... ISSUED AT 925 AM CDT TUE JUL 23 2013 THE 23.12Z 250 HPA RAOB MAP SHOWED WESTERLY TO NORTHWESTERLY FLOW STRETCHING FROM OREGON TO THE MIDWEST. MAGNITUDES WERE 50-75 KT. @ 500 HPA, AN ELONGATED 592/593 DM ANTICYCLONE EXTENDED FROM NORTHERN NEVADA SE TO NW NEW MEXICO. DOWNSTREAM, A BROAD TROF WAS MOVING ACROSS THE EASTERN UNITED STATES. @ 700 HPA, 2 DEG C OF WARMING OCCURRED AT KDDC BETWEEN 22.12Z AND 23.12Z SYNOPTIC FLIGHTS AND AT A FAIRLY WARM TEMP OF 15 DEG C THIS MORNING. @ 850 HPA, KDDC WAS AT 26 DEG C, WHICH IS ABOVE THE 75TH PERCENTILE. AT THE SFC, A LOW PRESSURE CENTER WAS LOCATED ACROSS FAR SW KANSAS. AN OUTFLOW BOUNDARY WAS DRAPED ACROSS THE FORECAST AREA OF RESPONSIBILITY. INVEST 98E WAS LOCATED 800 MILES SSW OF THE SOUTHERN TIP OF BAJA CALIFORNIA. INVEST 98L WAS LOCATED A COUPLE HUNDRED MILES SSE OF THE CAPE VERDE ISLANDS. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 200 PM CDT TUE JUL 23 2013 TONIGHT: NEAR TERM FORECAST CONCERN IS CONVECTION THIS AFTERNOON/EVENING. WSR- 88D AND SURFACE OBSERVATIONS SHOW A FEW BOUNDARIES ACROSS THE REGION THIS AFTERNOON. ONE IS A "COLD FRONT"/OUTFLOW BOUNDARY THIS IS ROUGHLY LOCATED FROM NESS CITY SE TO PRATT. A NONDESCRIPT DRYLINE IS THE OTHER BOUNDARY FARTHER WEST. THE INTERSECTION OF THESE TWO DENSITY GRADIENTS SHOULD BE WHERE CONVECTION INITIATES. THE MOST RECENT HRRR IS SHOWING AN ISOLATED STORM DEVELOPING JUST NORTHEAST OF DODGE CITY (MUCH LIKE YESTERDAY) AND THEN INDICATING THIS ACTIVITY DRIFTING OFF TO THE SE AS THE EARLY EVENING WEARS ON. THE NAM IS IN FAIR AGREEMENT WITH THIS SOLUTION. THE STORMS MAY BECOME SEVERE AS WELL AS 1-8 KM BULK SHEAR IS STRONGER THAN YESTERDAY...PLUS DEWPOINTS ARE STILL RUNNING FAIRLY HIGH, WHICH WILL CREATE ABOUT 1500-2000 J/KG OF SBCAPE. MODELS ALSO SHOW SOME DCAPE AS THE ATMOSPHERE BECOMES WELL MIXED. AS A RESULT, HAVE TWEAKED THE HWO WITH THE THREATS OF QUARTER SIZE HAIL, 60 MPH OUTFLOW, AND LIGHTNING AS THE MAIN CONCERNS. THIS ACTIVITY WILL CLEAR THE AREA LATER THIS EVENING AS THE FRONT SINKS SOUTHWARD. OVERNIGHT LOWS WILL BE IN THE 60S DEG F AND 70S DEG F. UPSLOPE STRATUS WILL BE POSSIBLE ON THE BACKSIDE OF THE LOW LEVEL PRESSURE PERTURBATION WITH UPSLOPE WINDS IN THE SFC-850 HPA LAYER. TOMORROW: AN UPSLOPE FLOW PATTERN IS EXPECTED TOMORROW IN THE WAKE OF THE AFOREMENTIONED BOUNDARY. MAXIMUMS WILL BE "COOLER" THAN COMPARED TO TODAY WITH VALUES IN THE UPPER 80S DEG F TO LOWER 90S DEG F. 23.12Z NAM SOLUTION IS WARMER COMPARED TO OTHER GUIDANCE, BUT THIS MIGHT BE A BIT OVERDONE. WILL USE THE ECMWF FOR NOW. OROGRAPHIC CONVECTION IS POSSIBLE IN THE UPSLOPE FLOW REGIME TOMORROW ACROSS EASTERN COLORADO. WILL CARRY SLIGHT PRECIPITATION PROBABILITY PERCENTAGE POINTS FOR FAR WEST KANSAS THROUGH 00Z TOMORROW NIGHT. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 353 PM CDT TUE JUL 23 2013 THE SYSTEM THAT MOVED WESTWARD ALONG THE SOUTHERN EDGE OF THE UPPER LEVEL RIDGE LAST WEEK WAS LOCATED NEAR THE CALIFORNIA COAST TODAY AND IS POISED TO MOVE BACK EASTWARD ON THE NORTHERN SIDE OF THE UPPER LEVEL RIDGE. BY WEDNESDAY NIGHT AND THURSDAY, THIS SYSTEM WILL BE APPROACHING FROM THE WEST. A STATIONARY FRONT WILL BE LOCATED OVER THE SOUTHERN PLAINS, WITH UPSLOPE FLOW AND ABUNDANT LOW LEVEL MOISTURE ON THE COOL SIDE OF THE FRONT OVER WESTERN KANSAS. WE ARE EXPECTING THUNDERSTORMS TO DEVELOP OVER COLORADO AND THEN EXPAND INTO A LARGER CLUSTER OF STORMS OVER THE PLAINS. THE EXACT POSITIONING OF THIS STORM CLUSTER IS UNCERTAIN. SO FOR NOW, RAIN CHANCES WERE KEPT AT 40-50% FOR LATE WEDNESDAY NIGHT INTO THURSDAY NIGHT. AFTER THE AFOREMENTIONED SYSTEM PASSES BY FRIDAY MORNING, A BREAK IN PRECIPITATION IS EXPECTED FRIDAY AND SATURDAY, WITH CONTINUED COOL WEATHER (HIGHS MAINLY IN THE 80S AND LOWS IN THE 60S). BY THE WEEKEND, THE MID TO UPPER LEVEL FLOW WILL BECOME MORE WEST-NORTHWESTERLY AGAIN, RESULTING IN RENEWED WEAK SURFACE LEE TROUGHING AND WARM/MOIST ADVECTION INTO WESTERN KANSAS. THEREFORE, THERE ARE CHANCES OF THUNDERSTORMS AGAIN BY SATURDAY NIGHT INTO MONDAY, WITH CONTINUED COOL WEATHER (HIGHS MAINLY 80S). && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1223 AM CDT WED JUL 24 2013 VFR CONDITIONS WILL BE THE RULE TODAY, ALONG WITH NORTHEAST WINDS OF 11G22KT. THERE IS A CHANCE FOR A LITTLE 5SM BKN025 CONDITIONS TOWARD SUNRISE, BUT THOSE CONDITIONS SHOULD NOT LAST PAST 13Z OR SO. WINDS LATER TODAY WILL BE NORTHEAST AT 15G25KT. && .PRELIMINARY POINT TEMPS/POPS... DDC 69 86 68 83 / 40 50 50 10 GCK 68 86 66 83 / 50 50 40 10 EHA 68 87 65 85 / 50 50 40 10 LBL 69 89 67 84 / 40 50 50 10 HYS 68 84 68 82 / 40 50 50 30 P28 71 89 70 84 / 40 50 50 40 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...SUGDEN SHORT TERM...SUGDEN LONG TERM...FINCH AVIATION...BURKE
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
411 AM EDT WED JUL 24 2013 .SYNOPSIS... HIGH PRESSURE WILL FINALLY BRING SOME QUIET AND COMFORTABLE WEATHER FOR THE REMAINDER OF THE WORK WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... TOUGHEST PART OF FORECAST TODAY...TRYING TO DETERMINE HOW FAST STRATO-CU DECK WILL DISSIPATE. THERE ARE LARGE HOLES THAT HAVE DEVELOPED IN THE LOW CLOUD DECK AND NONE OF THE MODELS ARE DOING A VERY GOOD JOB OF PICKING UP ON THIS. LATEST NAM AND HRRR ARE SIMILAR IN HOLDING ON TO THE CLOUD DECK AT LEAST THROUGH THE MORNING...DECAYING FROM THE NORTH AS THE DRIER AIR MOVES IN. HAVE SOME RESERVATIONS ON THIS...AS STATED PREVIOUSLY...MODELS ARE NOT DEPICTING CURRENT CONDITIONS WELL. WILL GO WITH A GRADUAL DECREASE IN CLOUD COVER FROM NORTH TO SOUTH THIS MORNING. DRIER AND COOLER AIR WILL ACCOMPANY A LARGE SURFACE HIGH...WHICH WILL MOVE THROUGH THE WESTERN GREAT LAKES TODAY. THE FLOW ALOFT WILL BECOME CYCLONIC AS A SHORTWAVE TROUGH MOVES TOWARD THE AREA LATE THIS AFTERNOON. WILL LEAN CLOSE TO CURRENT LAMP NUMBERS FOR HIGHS WHICH SHOULD BE WELL BELOW NORMAL. OVERALL CONDITIONS WILL BE VERY COMFORTABLE AS SFC TDS FALL IN THE LOWER TO MID 50S. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/... UPPER LEVEL TROUGH WILL HANG AROUND THROUGH MUCH OF THURSDAY NIGHT AS A DRY AIR MASS TAKES HOLD. EXPECT PLENTY OF SUNSHINE THURSDAY WITH BELOW NORMAL TEMPS. RIDGE WILL BUILD IN FRIDAY KEEPING THE AREA DRY AND WARMING TEMPS TO NEAR NORMAL LEVELS. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... A LONG WAVE TROUGH IS FORECAST TO CONTROL ERN CONUS WEATHER THROUGH THE WEEKEND. AS A RESULT...AOB SEASONAL AVERAGE TEMPS CAN BE EXPECTED AS WELL AS SHRTWV DEPENDENT PCPN CHCS. BEYOND THE WEEKEND...MDL CONSENSUS IS THAT THE TROF WL BGN TO FILL...HENCE THE NEW WEEK WL FEATURE WARMER TEMPS AND LOWER POPS. && .AVIATION /08Z WEDNESDAY THROUGH SUNDAY/... TSTMS HAVE MOVED OUT OF THE TERMINALS. A SHWR OR TSTM IS PSBL AS A CDFNT MOVES THRU OVRNGT BUT COVG TOO LTL FOR TAF INCLUSION. POST FRONTAL MVFR STRATOCU SEEN ON STLT MOVG S AND THIS SHOULD AFFECT THE TERMINALS OVRNGT INTO WED MRNG. CIGS SHOULD LIFT TO VFR BY LT MRNG AND GRDLY SCT OUT THRU THE DAY. OUTLOOK.../WEDNESDAY NIGHT THROUGH SUNDAY/... VFR CONDS EXPD THRU SAT MRNG. RESTRNS ARE PSBL WITH THE APPRCH AND PASSAGE OF A WEEKEND CDFNT. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
307 AM EDT WED JUL 24 2013 .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 411 PM EDT TUE JUL 23 2013 WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A VIGOROUS SHORTWAVE OVER JAMES BAY. PRES GRADIENT BTWN ITS ASSOCIATED SFC LOW E OF JAMES BAY AND SFC HIGH PRES OVER NW MN/ERN DAKOTAS HAS RESULTED IN BREEZY N/NW WINDS TODAY AND MUCH COOLER CONDITIONS COMPARED TO YESTERDAY. PER WATER VAPOR IMAGERY...IN THE NW FLOW UPSTREAM...THERE ARE A COUPLE OF SHORTWAVES EVIDENT...ONE OVER ERN MT/WRN ND AND ANOTHER OVER CNTRL SASKATCHEWAN. THE NRN WAVE MAY BE A FACTOR IN THE WEATHER HERE ON WED. A QUIET...COOL NIGHT IS IN STORE TONIGHT AS SFC HIGH PRES SETTLES SE INTO WI...BRINGING DIMINISHING WINDS FROM W TO E. WITH DECREASING WINDS...CLEAR SKIES AND PRECIPITABLE WATER 50-70PCT OF NORMAL... EXPECT A DECENT RADIATIONAL COOLING NIGHT...ESPECIALLY OVER W AND SW UPPER MI AS WINDS SHOULD DIMINISH TO CALM IN THAT AREA...BEING CLOSER TO SFC HIGH PRES CENTER. WILL CONTINUE TO SHOW LOWEST TEMPS IN THAT AREA (40 TO THE LWR 40S). OTHERWISE...MIN TEMPS SHOULD BE IN THE 40S IN THE INTERIOR TO MOSTLY AROUND 50F ALONG THE GREAT LAKES. AFTER A QUIET NIGHT...ATTENTION ON WED SHIFTS TO POSSIBLE AFTN CONVECTION. SUMMERTIME WNW/NW FLOW IS OFTEN A FAVORABLE PATTERN FOR ISOLD/SCT AFTN CONVECTION AS EVEN THE MOST SUBTLE SHORTWAVES CAN SPARK SOME PCPN. IF THERE WASN`T A SHORTWAVE PRESENT UPSTREAM... WOULD HAVE DROPPED PCPN MENTION ON WED...BUT SINCE THERE IS AN OBVIOUS WAVE CURRENTLY UPSTREAM IN CNTRL SASKATCHEWAN...IT LOOKS LIKE THERE WILL PROBABLY BE SOME ISOLD AFTN CONVECTION AS THE WAVE DROPS SE INTO THE AREA. WILL CONTINUE TO HIGHLIGHT SCHC POPS OVER MAINLY THE INTERIOR W AND CNTRL WHERE THE LIMITED INSTABILITY IS BEST. NAM/GFS MLCAPES ARE ONLY AS HIGH AS 200-300J/KG DURING THE MID AFTN...SO THUNDER POTENTIAL APPEARS MINIMAL. HOWEVER...CANADIAN RADARS CURRENTLY SHOW DECENT RETURNS IN THE VCNTY OF SHORTWAVE IN SASKATCHEWAN AND SATELLITE IMAGERY SUGGESTS SOME DECENT CONVECTION...SO THERE MAY BE SOME THUNDER OCCURRING WITH THE WAVE THIS AFTN. FOR NOW...WILL LEAVE THUNDER MENTION IN THE FCST FOR WED AND LET LATER SHIFTS REASSESS. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 411 PM EDT TUE JUL 23 2013 MUCH OF THE LONG TERM PERIOD WILL BE INFLUENCED BY A SHORTWAVE DROPPING SOUTH-SOUTHEAST THROUGH CENTRAL CANADA ON WEDNESDAY AND WEDNESDAY NIGHT...WHICH THEN MOVES INTO CENTRAL ONTARIO BY THURSDAY NIGHT AND CLOSES OFF. THIS UPPER LOW WILL REMAIN IN CENTRAL ONTARIO INTO SUNDAY BEFORE SHIFTING NORTHEAST INTO ONTARIO FOR THE START OF THE WORK WEEK. WEDNESDAY NIGHT WILL BE RELATIVELY QUIET AS ANY DIURNAL CLOUDS AND SHOWERS DIMINISH FAIRLY QUICKLY DURING THE EVENING. THEN...EXPECT MID-HIGH CLOUDS TO BE ON THE INCREASE THROUGH THE NIGHT AS THE SHORTWAVE MOVES INTO SOUTHWEST ONTARIO AND AN ASSOCIATED 1008MB LOW DEVELOPS EAST OF LAKE WINNIPEG AND SLIDES EAST. AS THE SHORTWAVE AND SURFACE LOW CONTINUE TO THE EAST-SOUTHEAST ON LATE WEDNESDAY NIGHT AND THURSDAY...AN ASSOCIATED COLD FRONT WILL SLIDE INTO WESTERN UPPER MICHIGAN DURING THE AFTERNOON. THAT WILL BE THE AREA WITH THE BEST OPPORTUNITY FOR SHOWERS/THUNDERSTORMS ON THURSDAY AFTERNOON AND WILL CONTINUE TO HIGHLIGHT INCREASING POPS TO LIKELY VALUES DURING THE AFTERNOON. INSTABILITY LOOKS FAIRLY LIMITED OVER MOST OF THE AREA...WITH MLCAPE VALUES AROUND 500 J/KG ALTHOUGH MUCAPE VALUES DO APPROACH 1500 J/KG IN SOME MODELS OVER THE WEST AND 09Z SREF ONLY INDICATES A 20 PERCENT CHANCE 1000 J/KG IS REACHED. CAPE IS FAIRLY TALL/SKINNY AS SEEN IN NCAPE VALUES IN THE 0.05-0.1 RANGE. AS FOR SHEAR...0-6KM AND EFFECTIVE VALUES ARE ALSO MARGINAL (AROUND 30-35KTS)...ALTHOUGH THERE IS SOME LOW LEVEL VEERING TO THE WIND. THE STRENGTH OF THE SHORTWAVE MAY HELP OVERCOME THE MARGINAL INSTABILITY/SHEAR...BUT THINK THE STORMS WILL PRIMARILY BE SUB SEVERE. THEY WILL LIKELY BE THE STRONGEST OVER THE FAR WEST...WHERE IT IS CLOSER TO THE SYNOPTIC AND FRONTAL FORCING. NAM/GFS STORM MOTION VECTORS INDICATE THE STORMS WILL MOVE FAIRLY QUICKLY TO THE EAST (AROUND 40KTS) AND HAVE FOLLOWED SUIT WITH THE POPS. BUT THE OVERALL TREND WITH THE FRONT HAS BEEN SLOWER...WITH IT NOW EXITING EASTERN UPPER MICHIGAN BETWEEN 09Z-18Z FRIDAY. MODELS DIFFER SOMEWHAT WITH THE POSITION OF THE SURFACE/UPPER LOW...BUT THE GENERAL IDEA OF COOL...CYCLONIC FLOW AFFECTING THE UPPER GREAT LAKES FRIDAY THROUGH SUNDAY MORNING SEEMS REASONABLE. ANOTHER SHORTWAVE ROTATES AROUND THE UPPER LOW ON FRIDAY AND PRECIPITATION CHANCES DEPEND ON HOW QUICKLY THE FRONT MOVES EAST...THE DRY SLOT BEHIND IT...AND ADDITIONAL MOISTURE DROPPING SOUTHEAST ACROSS WESTERN LAKE SUPERIOR. THESE FEATURES ARE STILL VARIABLE IN THE MODELS...BUT THE MORNING LOOKS TO HAVE THE BEST OPPORTUNITY FOR LINGERING SHOWERS OVER THE SE U.P. TRIED TO SHOW A LITTLE MORE TIMING ON POPS FOR FRIDAY BUT CONFIDENCE WASN/T HIGH ENOUGH TO SHOW DRY PERIODS UNDER THE DRY SLOT. WITH THE MOISTURE WRAPPING AROUND THE UPPER LOW FRIDAY NIGHT INTO SATURDAY NIGHT...EXPECT THERE TO BE PERIODS OF CLOUDS...ESPECIALLY FRIDAY NIGHT INTO SATURDAY. MOST OF THE MOISTURE IS FAIRLY SHALLOW...BUT THERE MAY BE ENOUGH AROUND FOR SOME LIGHT RAIN SHOWERS/DRIZZLE ON FRIDAY NIGHT INTO SATURDAY AND WILL RETAIN SLIGHT CHANCE POPS. TEMPERATURES THIS WEEKEND WILL VERY COOL FOR LATE JULY STANDARDS...WITH LOW 60S ON SATURDAY (10-15 DEGREES BELOW NORMAL) AND MID-UPPER 60S FOR SUNDAY. THE UPPER LOW SHIFTS AWAY ON SUNDAY AFTERNOON AND THE AREA WILL BE BACK UNDER WEST-NORTHWEST FLOW ALOFT. BOTH GFS/ECMWF ARE SHOWING A SHORTWAVE AND ASSOCIATED WARM FRONT MOVING TOWARDS THE AREA SOMETIME MONDAY TO TUESDAY AND HAVE SLOWLY BROUGHT POPS UP TO CHANCES BY TUESDAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1203 AM EDT WED JUL 24 2013 HIGH PRES BUILDING INTO THE AREA...EXPECT VFR CONDITIONS TO DOMINATE THRU THIS FCST PERIOD AT KIWD/KCMX/KSAW. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 307 AM EDT WED JUL 24 2013 THERE WILL BE LITTLE CHANGE PRESSURE WISE THROUGH THE WEEKEND...WITH WINDS LESS THAN 20KTS /EXCLUDING NEAR THUNDERSTORMS/. HIGH PRESSURE ACROSS THE UPPER GREAT LAKES WILL SLOWLY DRIFT ACROSS THE LOWER GREAT LAKES TONIGHT...WHERE IT WILL LINGER THROUGH FRIDAY. IN THE MEANTIME...LOW PRESSURE ACROSS SOUTHERN MANITOBA SHOULD PUSH ACROSS INTO WESTERN LAKE SUPERIOR THURSDAY AFTERNOON BEFORE SLOWLY EXITING EASTERN LAKE SUPERIOR FRIDAY AFTERNOON. EXPECT THE LOW TO DEEPEN SLIGHTLY ACROSS EASTERN ONTARIO FROM LATE FRIDAY THROUGH THE WEEKEND...LEAVING A TROUGH ACROSS LAKE SUPERIOR. HIGH PRESSURE WILL ATTEMPT TO PUSH INTO FAR WESTERN LAKE SUPERIOR TOWARD THE END OF THE WEEKEND AND INTO THE START OF THE NEXT WORK WEEK. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...ROLFSON LONG TERM...SRF AVIATION...07 MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1203 AM EDT WED JUL 24 2013 .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 411 PM EDT TUE JUL 23 2013 WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A VIGOROUS SHORTWAVE OVER JAMES BAY. PRES GRADIENT BTWN ITS ASSOCIATED SFC LOW E OF JAMES BAY AND SFC HIGH PRES OVER NW MN/ERN DAKOTAS HAS RESULTED IN BREEZY N/NW WINDS TODAY AND MUCH COOLER CONDITIONS COMPARED TO YESTERDAY. PER WATER VAPOR IMAGERY...IN THE NW FLOW UPSTREAM...THERE ARE A COUPLE OF SHORTWAVES EVIDENT...ONE OVER ERN MT/WRN ND AND ANOTHER OVER CNTRL SASKATCHEWAN. THE NRN WAVE MAY BE A FACTOR IN THE WEATHER HERE ON WED. A QUIET...COOL NIGHT IS IN STORE TONIGHT AS SFC HIGH PRES SETTLES SE INTO WI...BRINGING DIMINISHING WINDS FROM W TO E. WITH DECREASING WINDS...CLEAR SKIES AND PRECIPITABLE WATER 50-70PCT OF NORMAL... EXPECT A DECENT RADIATIONAL COOLING NIGHT...ESPECIALLY OVER W AND SW UPPER MI AS WINDS SHOULD DIMINISH TO CALM IN THAT AREA...BEING CLOSER TO SFC HIGH PRES CENTER. WILL CONTINUE TO SHOW LOWEST TEMPS IN THAT AREA (40 TO THE LWR 40S). OTHERWISE...MIN TEMPS SHOULD BE IN THE 40S IN THE INTERIOR TO MOSTLY AROUND 50F ALONG THE GREAT LAKES. AFTER A QUIET NIGHT...ATTENTION ON WED SHIFTS TO POSSIBLE AFTN CONVECTION. SUMMERTIME WNW/NW FLOW IS OFTEN A FAVORABLE PATTERN FOR ISOLD/SCT AFTN CONVECTION AS EVEN THE MOST SUBTLE SHORTWAVES CAN SPARK SOME PCPN. IF THERE WASN`T A SHORTWAVE PRESENT UPSTREAM... WOULD HAVE DROPPED PCPN MENTION ON WED...BUT SINCE THERE IS AN OBVIOUS WAVE CURRENTLY UPSTREAM IN CNTRL SASKATCHEWAN...IT LOOKS LIKE THERE WILL PROBABLY BE SOME ISOLD AFTN CONVECTION AS THE WAVE DROPS SE INTO THE AREA. WILL CONTINUE TO HIGHLIGHT SCHC POPS OVER MAINLY THE INTERIOR W AND CNTRL WHERE THE LIMITED INSTABILITY IS BEST. NAM/GFS MLCAPES ARE ONLY AS HIGH AS 200-300J/KG DURING THE MID AFTN...SO THUNDER POTENTIAL APPEARS MINIMAL. HOWEVER...CANADIAN RADARS CURRENTLY SHOW DECENT RETURNS IN THE VCNTY OF SHORTWAVE IN SASKATCHEWAN AND SATELLITE IMAGERY SUGGESTS SOME DECENT CONVECTION...SO THERE MAY BE SOME THUNDER OCCURRING WITH THE WAVE THIS AFTN. FOR NOW...WILL LEAVE THUNDER MENTION IN THE FCST FOR WED AND LET LATER SHIFTS REASSESS. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 411 PM EDT TUE JUL 23 2013 MUCH OF THE LONG TERM PERIOD WILL BE INFLUENCED BY A SHORTWAVE DROPPING SOUTH-SOUTHEAST THROUGH CENTRAL CANADA ON WEDNESDAY AND WEDNESDAY NIGHT...WHICH THEN MOVES INTO CENTRAL ONTARIO BY THURSDAY NIGHT AND CLOSES OFF. THIS UPPER LOW WILL REMAIN IN CENTRAL ONTARIO INTO SUNDAY BEFORE SHIFTING NORTHEAST INTO ONTARIO FOR THE START OF THE WORK WEEK. WEDNESDAY NIGHT WILL BE RELATIVELY QUIET AS ANY DIURNAL CLOUDS AND SHOWERS DIMINISH FAIRLY QUICKLY DURING THE EVENING. THEN...EXPECT MID-HIGH CLOUDS TO BE ON THE INCREASE THROUGH THE NIGHT AS THE SHORTWAVE MOVES INTO SOUTHWEST ONTARIO AND AN ASSOCIATED 1008MB LOW DEVELOPS EAST OF LAKE WINNIPEG AND SLIDES EAST. AS THE SHORTWAVE AND SURFACE LOW CONTINUE TO THE EAST-SOUTHEAST ON LATE WEDNESDAY NIGHT AND THURSDAY...AN ASSOCIATED COLD FRONT WILL SLIDE INTO WESTERN UPPER MICHIGAN DURING THE AFTERNOON. THAT WILL BE THE AREA WITH THE BEST OPPORTUNITY FOR SHOWERS/THUNDERSTORMS ON THURSDAY AFTERNOON AND WILL CONTINUE TO HIGHLIGHT INCREASING POPS TO LIKELY VALUES DURING THE AFTERNOON. INSTABILITY LOOKS FAIRLY LIMITED OVER MOST OF THE AREA...WITH MLCAPE VALUES AROUND 500 J/KG ALTHOUGH MUCAPE VALUES DO APPROACH 1500 J/KG IN SOME MODELS OVER THE WEST AND 09Z SREF ONLY INDICATES A 20 PERCENT CHANCE 1000 J/KG IS REACHED. CAPE IS FAIRLY TALL/SKINNY AS SEEN IN NCAPE VALUES IN THE 0.05-0.1 RANGE. AS FOR SHEAR...0-6KM AND EFFECTIVE VALUES ARE ALSO MARGINAL (AROUND 30-35KTS)...ALTHOUGH THERE IS SOME LOW LEVEL VEERING TO THE WIND. THE STRENGTH OF THE SHORTWAVE MAY HELP OVERCOME THE MARGINAL INSTABILITY/SHEAR...BUT THINK THE STORMS WILL PRIMARILY BE SUB SEVERE. THEY WILL LIKELY BE THE STRONGEST OVER THE FAR WEST...WHERE IT IS CLOSER TO THE SYNOPTIC AND FRONTAL FORCING. NAM/GFS STORM MOTION VECTORS INDICATE THE STORMS WILL MOVE FAIRLY QUICKLY TO THE EAST (AROUND 40KTS) AND HAVE FOLLOWED SUIT WITH THE POPS. BUT THE OVERALL TREND WITH THE FRONT HAS BEEN SLOWER...WITH IT NOW EXITING EASTERN UPPER MICHIGAN BETWEEN 09Z-18Z FRIDAY. MODELS DIFFER SOMEWHAT WITH THE POSITION OF THE SURFACE/UPPER LOW...BUT THE GENERAL IDEA OF COOL...CYCLONIC FLOW AFFECTING THE UPPER GREAT LAKES FRIDAY THROUGH SUNDAY MORNING SEEMS REASONABLE. ANOTHER SHORTWAVE ROTATES AROUND THE UPPER LOW ON FRIDAY AND PRECIPITATION CHANCES DEPEND ON HOW QUICKLY THE FRONT MOVES EAST...THE DRY SLOT BEHIND IT...AND ADDITIONAL MOISTURE DROPPING SOUTHEAST ACROSS WESTERN LAKE SUPERIOR. THESE FEATURES ARE STILL VARIABLE IN THE MODELS...BUT THE MORNING LOOKS TO HAVE THE BEST OPPORTUNITY FOR LINGERING SHOWERS OVER THE SE U.P. TRIED TO SHOW A LITTLE MORE TIMING ON POPS FOR FRIDAY BUT CONFIDENCE WASN/T HIGH ENOUGH TO SHOW DRY PERIODS UNDER THE DRY SLOT. WITH THE MOISTURE WRAPPING AROUND THE UPPER LOW FRIDAY NIGHT INTO SATURDAY NIGHT...EXPECT THERE TO BE PERIODS OF CLOUDS...ESPECIALLY FRIDAY NIGHT INTO SATURDAY. MOST OF THE MOISTURE IS FAIRLY SHALLOW...BUT THERE MAY BE ENOUGH AROUND FOR SOME LIGHT RAIN SHOWERS/DRIZZLE ON FRIDAY NIGHT INTO SATURDAY AND WILL RETAIN SLIGHT CHANCE POPS. TEMPERATURES THIS WEEKEND WILL VERY COOL FOR LATE JULY STANDARDS...WITH LOW 60S ON SATURDAY (10-15 DEGREES BELOW NORMAL) AND MID-UPPER 60S FOR SUNDAY. THE UPPER LOW SHIFTS AWAY ON SUNDAY AFTERNOON AND THE AREA WILL BE BACK UNDER WEST-NORTHWEST FLOW ALOFT. BOTH GFS/ECMWF ARE SHOWING A SHORTWAVE AND ASSOCIATED WARM FRONT MOVING TOWARDS THE AREA SOMETIME MONDAY TO TUESDAY AND HAVE SLOWLY BROUGHT POPS UP TO CHANCES BY TUESDAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1203 AM EDT WED JUL 24 2013 HIGH PRES BUILDING INTO THE AREA...EXPECT VFR CONDITIONS TO DOMINATE THRU THIS FCST PERIOD AT KIWD/KCMX/KSAW. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 411 PM EDT TUE JUL 23 2013 AFTER A PERIOD OF STRONG WINDS TODAY ACROSS LAKE SUPERIOR IN THE WAKE OF A COLD FRONT...LIGHTER WINDS UNDER 20KT WILL BE THE RULE TONIGHT INTO WED AS HIGH PRES BUILDS INTO THE WRN GREAT LAKES. AS THE HIGH SHIFTS E AND LOW PRES APPROACHES FROM THE NW...WINDS WILL BECOME SOUTHERLY WED NIGHT/THU...BUT REMAIN UNDER 20KT. EVEN AFTER THE LOW PASSES THRU THE UPPER GREAT LAKES/NRN ONTARIO...WINDS WILL PROBABLY REMAIN 20KT OR LESS LATE WEEK AND THRU THE WEEKEND. HOWEVER...WILL NEED TO WATCH FOR STRONGER SOUTHERLY WINDS THU NIGHT JUST AHEAD OF THE LOW AND ASSOCIATED COLD FRONT AND THEN LATER FRI INTO SAT BEHIND COLD FRONT. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...ROLFSON LONG TERM...SRF AVIATION...07 MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
418 AM CDT WED JUL 24 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 259 AM CDT WED JUL 24 2013 SPRAWLING COOL AND DRY CANADIAN HIGH IN PLACE AT THE SFC TO START OFF THE DAY. UPSTAIRS THOUGH...A WAVY NW FLOW HAS KEPT A STEADY DIET OF MID CLOUDS STREAMING ACROSS THE AREA OVERNIGHT...WHICH HAS KEPT TEMPS FROM FALLING OFF AS MUCH THEY COULD...ESPECIALLY OVER MN. FOR THE REST OF THE SHORT TERM...WE WILL SEE HEIGHTS BUILD SOME TODAY OUT AHEAD OF A STRONG SHORTWAVE MOVING THROUGH THE CANADIAN PRAIRIES TOWARD NRN MN BY THE END OF THE PERIOD. AT THE SFC...THE HIGH WILL SLIP INTO THE GREAT LAKES WHILE A COLD FRONT SLIPS ACROSS NODAK AND INTO NW MN BY THURSDAY MORNING. BIG QUESTION FOR TODAY WAS TO OR NOT TO INCLUDE SOME ISO THUNDER IN THE FORECAST. IF YOU HEAD OFF IN SEARCH OF YOUR FAVORITE CAM...YOU LIKELY HAVE SEEN THAT MOST GENERATE SOME ISOLATED CONVECTION BY THE AFTERNOON SOMEWHERE NEAR THE I-35 CORRIDOR...BUT AFTER TAKING A PEAK AT SOME DETERMINISTIC GUIDANCE TO SUPPORT THE ISO STORMS...DECIDED AGAINST INCLUDING ANYTHING THROUGH THE AFTERNOON IN THE GRIDS. THERE WERE TWO THINGS THAT PUSHED ME TOWARD A DRY FORECAST FOR TODAY. FIRST...THE RAP CONTINUES TO SHOW NO MUCAPE ACROSS THE MPX AREA THIS AFTERNOON...WITH BEST LI/S REMAINING ABOVE ZERO...NOT EXACTLY WHAT YOU WANT TO SEE FOR THUNDERSTORMS. SECOND...EVEN THOUGH THE NAM GENERATES 500-1000 J/KG OF MLCAPE BY THE AFTERNOON...A QUICK LOOK AT SOUNDINGS ACROSS THE AREA SHOWS THAT IT IS A VERY SKINNY CAPE PROFILE AND ONE THAT DOES NOT LOOK PROMISING FOR GENERATING DEEP MOIST CONVECTION. SO AFTER MUCH DEBATE...DECIDED TO JOIN THE GEM AND ECMWF IN GOING DRY FOR TODAY. THIS EVENING/TONIGHT...PRECIP CHANCES DO LOOK AT LEAST MARGINALLY BETTER. THE REASON IS THAT AS THE STRONG SHORTWAVE DROPS SOUTH OUT OF CANADA...WE WILL SEE H85 WINDS...MOISTURE TRANSPORT AND WAA SLOWLY INCREASING DURING THE NIGHT. THOUGH NOT IMPRESSIVE BY ANY MEANS...USUALLY A PRETTY RISKY PROPOSITION TO NOT INCLUDE SOME POPS FOR A NIGHT TIME PERIOD IN THE SUMMER THAT FEATURES AT LEAST WEAK WAA AND MOISTURE TRANSPORT AT THE H85 LEVEL. MOST LIKELY SCENARIO AT THE MOMENT LOOKS TO BE REMNANTS OF CONVECTION THAT DEVELOPS IN NRN MN THIS AFTERNOON DROPPING SE INTO EC MN AND WRN WI OVERNIGHT. FOR NOW HAVE CHANCE POPS ROUGHLY ALONG AND NORTH OF I-94...THOUGH DO NOT HAVE MUCH CONFIDENCE IN HOW STORMS TONIGHT WILL PLAY OUT AT THE MOMENT. FOR TEMPERATURES...925-850 TEMPS INCREASE TO BETWEEN 16C AND 20C OUT IN WRN MN THIS AFTERNOON...WHICH WILL SUPPORT TEMPERATURES WARMING INTO THE LOW-MID 80S IF CLOUD COVER DOES NOT SLOW THINGS DOWN TOO MUCH. AS A RESULT...DID NUDGE HIGHS UP A COUPLE OF DEGREES OUT WEST...BUT WILL HAVE TO SEE HOW CLOUDS PLAY OUT. TONIGHT...WEAK SRLY FLOW AND WAA SHOULD KEEP TEMPS SIMILAR TO WHAT WE ARE SEEING UNDER THE CLOUDS IN MN TONIGHT...AND ABOUT 5 DEGS WARMER THAN WHAT WE ARE SEEING OVER IN WI RIGHT NOW. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 259 AM CDT WED JUL 24 2013 MAIN ISSUE IN THE LONG TERM IS THUNDERSTORMS AND POTENTIAL FOR SEVERE WX THU AFTN AND EVE...THEN THE MUCH COOLER TEMPERATURES EXPECTED FOR THE WEEKEND. AN UPPER LEVEL LOW CENTER WILL DROP OUT OF MANITOBA THU MRNG SWWD ON ITS WAY INTO THE GRT LAKES. AT THE SFC...A POTENT CDFNT WILL BE LINKED BY TWO ANCHOR LOW PRES CENTERS...ONCE JUST N OF KINL AND THE OTHER OVER SW SD BY MIDDAY WED. THESE TWO SFC LOW PRES CENTERS WILL PHASE TOGETHER OVER THE GRT LAKES BY MIDDAY FRI...SHOVING THE CDFNT THRU THE REGION FRI MRNG WHILE THE UPPER LEVEL LOW DEEPENS INTO A POTENT COMPACT LONGWAVE TROUGH OVER THE UPPER MISSISSIPPI RIVER VALLEY. EFFICIENT WARM SECTORING AHEAD OF THE CDFNT WILL DRAG WARM AND MORE MOIST AIR FROM THE DEEP S UP INTO THE REGION FOR MID-TO-LATE THU. STRONG JETTING IN THE MID- AND UPPER-LEVELS WILL ENHANCE TSTM DEVELOPMENT DURG THE DAY ON THU. OF NOTE HOWEVER IS COLD AIR ALOFT...A FUNCTION OF THE UPPER LOW DROPPING S. THIS WILL ALLOW GROWING STORMS TO HIT THE FREEZING LEVEL QUICKLY... WORKING WITH STEEP LAPSE RATES TO MAKE LARGE HAIL A SEVERE WX HAZARD. IN ADDITION...HELICITIES INCRS SIGNIFICANTLY INVOF THE FNT WITH SWLY WINDS AT THE SFC AND NW FLOW ALOFT DUE TO LOCATION OF THE UPPER LOW. ISOLD TORNADOES...PARTICULARLY OVER SRN MN...ARE ANOTHER POTENTIAL SEVERE WX HAZARD. THE SPC HAS ADDED A SLGT RISK FOR SRN-ERN MN INTO WRN WI IN THE MORNING SWODY2 AND THIS IS WELL WARRANTED. THE CDFNT WILL SHIFT WELL INTO THE GRT LAKES BY FRI EVE...ALLOWING DEEP N-NW FLOW CAA TO COMMENCE. THE UPPER LOW WILL THE SIT-AND- SPIN OVER THE GRT LAKES THRU SUN...KEEPING TEMPERATURES 10-12 DEGREES BELOW NORMAL FRO THRU THE WEEKEND. H85 TEMPS DROP TO ABOUT 6-8 DEG C...WHICH WILL TRANSLATE TO LOWS ARND 50 AND HIGHS ARND 70 FRI THRU SUN. THE DENSE SFC HIGH PRES ASSOCIATED WITH THIS COOLDOWN WILL SHIFT TO THE E DURING THE EARLY PORTION OF NEXT WEEK...ALLOWING FOR A WARMER RETURN FLOW ON THE BACKSIDE OF THE HIGH. TEMPS WILL RISE BACK CLOSER TO NORMAL LEVELS WHILE SEVERAL SHORTWAVE DISTURBANCES RIDE WITHIN THE FLOW BETWEEN A RIDGE OVER THE PLAINS AND A TROUGH OVER THE APPALACHIANS. THESE DISTURBANCES MAY BE ABLE TO SQUEEZE ENOUGH LIMITED MOISTURE TO PRODUCE ISOLD TO SCATTERED SHOWERS AND TSTMS MON-TUE. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1148 PM CDT TUE JUL 23 2013 ONLY AVIATION CONCERN IS WHETHER A WEAKENING DISTURBANCE ACROSS SERN ND LATE THIS EVENING CAN GENERATE ISOLD TSRA/SHRA ACROSS WESTERN MN TOWARD DAYBREAK. RWF WOULD BE ON THE EASTERN FRINGES OF THIS ACTIVITY. ELSEWHERE...VFR CONDS WILL CONTINUE WITH CALM WINDS TONIGHT BECOMING W/SW AFT 14Z. KMSP...VFR CONDITIONS EXPECTED WITH LGT/VAR WINDS BECOMING SOUTHWESTERLY WEDNESDAY MORNING. /OUTLOOK FOR KMSP/ THU...CHC SHRA/TSRA. VFR OUTSIDE OF SHRA/TSRA. WINDS SW 5-10 KT. FRI...VFR. WINDS NW 10 KT. SAT...VFR. WINDS NW 5-10 KT. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...MPG LONG TERM...JPC AVIATION...BORGHOFF
AREA FORECAST DISCUSSION
NWS JACKSON MS
431 AM CDT WED JUL 24 2013 .SHORT TERM...(TODAY THROUGH THURSDAY NIGHT)... COMPLICATED NORTHWEST FLOW REGIME PERSISTS OVER THE NEXT COUPLE DAYS...ALTHOUGH THINGS WILL SIMPLIFY A TAD HEADED INTO TOMORROW AS A COOL FRONT DRIFTS INTO THE AREA FROM THE NORTH. BUT BEFORE THEN WE NEED TO DEAL WITH A RATHER UNCERTAIN FORECAST FOR TODAY. A REMNANT MCV FROM A CONVECTIVE COMPLEX THAT DIED TO OUR WEST LAST NIGHT IS CURRENTLY DRIFTING ACROSS NORTHEAST LOUISIANA TOWARD SOUTHWEST MISSISSIPPI AT THIS HOUR...WITH A BROAD CIRRUS SHIELD TRYING TO OVERSPREAD THE REGION FROM THE NORTHWEST. THESE TWO ITEMS ARE GOING TO MAKE A CONVECTIVE FORECAST FOR TODAY RATHER DIFFICULT AS CONVERGENCE IN VICINITY OF THE MCV CALLS FOR INITIATION IN ITS VICINITY ONCE WE HEAT UP...WITH EXPANSIVE UPPER CLOUD COVER LIMITING THE HEATING POTENTIAL/AT LEAST FOR THE FIRST PART OF THE DAY. FURTHER NORTH...THE SYNOPTIC COOL FRONT LOOKS TO BE PASSING INTO FAR NORTHERN MS BY LATE MORNING WHICH SHOULD PROVIDE IMPETUS FOR SOME STORMS IN ITS VICINITY AS LONG AS WE GET SOME HEATING UP THERE/BUT THERE AGAIN THE EXPANSIVE CIRRUS SHIELD IS GOING TO MAKE THAT DIFFICULT FOR SEVERAL MORE HOURS. THE BROADER SCALE MODELS DO NOT SEEM TO HAVE A GOOD HANDLE ON WHAT IS GOING ON WHICH ISN`T SURPRISING...HOWEVER THE LATEST RUNS OF THE HRRR DO LOOK REASONABLE WITH THEIR EVOLUTION OF THINGS FOR TODAY AND HAVE LOOKED TO IT MORE THAN ANYTHING FOR SOME CLUES. I WOULD NOT BE SURPRISED TO SEE THE CIRRUS THIN HEADED INTO THE DAYBREAK HOURS ALLOWING SOME DECENT HEATING TO OCCUR THIS MORNING ACROSS A GOOD MAJORITY OF THE REGION. THIS IN CONJUNCTURE WITH THE REMNANT MCV AND SURFACE FRONT SHOULD ALLOW A COUPLE FOCUS AREAS FOR STORMS TO DEVELOP...ONE ACROSS THE I-20 CORRIDOR ON THE NORTHERN FRINGE OF THE MCV AND ANOTHER NORTH OF OUR CWA INVOF THE FRONT. FROM THERE I`D EXPECT A GENERAL EXPANSION TOWARD THE SOUTH/SOUTHEAST LIKE WE`VE SEEN ACROSS THE REGION THE LAST COUPLE DAYS. THIS WOULD LEAVE A MINIMUM IN ACTIVITY ACROSS THE DELTA TODAY...HOWEVER IF THE CIRRUS THINS UP THERE AS WELL AND WE GET SOME HEATING A CONDITIONAL RISK OF STORMS FIRING IN THAT VICINITY INVOF THE FRONT LOOKS POSSIBLE. AS FOR THE STRONG/SEVERE RISK TODAY...RELIED HEAVILY ON THE LATEST RUNS OF THE RUC AND ITS TEMPERATURE PROFILE TODAY WHICH LOOKS PRETTY MEAGER ON THE LAPSE RATE FRONT GIVEN ALL THE CONVECTIVE DEBRIS/CIRRUS AROUND. COINCIDENT WITH THE UNCERTAINTY IN WHERE THE BEST COVERAGE IN STORMS WILL BE TODAY AM GOING TO LEAVE THE HWO PRETTY GENERAL WITH ALL AREAS COVERED...AND WILL OMIT MENTION OF ANYTHING SEVERE UNTIL CONFIDENCE INCREASES IN STRONGER HEATING/INSTABILITY DEVELOPING. HEADED INTO TONIGHT...I WOULD NOT BE SURPRISED TO SEE THINGS QUIET DOWN AREA WIDE BY MID TO LATE EVENING AS A LOSS OF HEATING COUPLES WITH DRIER AIR ALOFT OVERSPREADING THE CWA. ISOLATED SHOWERS AND PERHAPS A FEW RUMBLES OF THUNDER LOOK PLAUSIBLE ALONG THE ADVANCING FRONT THROUGH THE NIGHT. BY THURSDAY MORNING THE FRONT LOOKS TO BE LOCATED ALONG/JUST SOUTH OF THE I-20 CORRIDOR. THIS SHOULD CONFINE ANY SHOWER AND STORM CHANCES TO SOUTHERN ZONES...AND AT THIS POINT IT DOESN`T APPEAR STRONG STORMS WILL BE A HUGE CONCERN. WE`LL BE TAKING A LOOK AT THAT AGAIN LATER TODAY/TONIGHT. TEMPS OFFERED BY THE GFS MOS LOOKED WARM TODAY CONSIDERING THE AFOREMENTIONED CLOUDS/CIRRUS AND STORM CHANCES FOR LATER ON. ONLY OTHER NOTABLE CHANGES WERE FOR FRI MORNING WHERE TEMPS WERE RAISED A TAD TOWARD WARMER NAM/ENSEMBLE NUMBERS. /BK/ .LONG TERM...(FRIDAY THROUGH WEDNESDAY)... FOCUS OF THE LONG TERM WILL BE ON A WELL DEFINED DISTURBANCE FOR SATURDAY AND WHAT SORT OF PRECIP/IMPACTS IT COULD BRING FOR THE FRIDAY NIGHT THROUGH SATURDAY NIGHT TIMEFRAME. OUTSIDE THAT...A RETURN TO MORE TYPICAL SUMMER CONDITIONS ARE EXPECTED BY NEXT WEEK AFTER A BRIEF VISIT BY A LATE JULY FRONTAL BOUNDARY. ON FRI...WARM CONDITIONS WILL EXIST AS THE AREA SEES A STALLED SFC FRONT LIFT BACK NORTHWARD AS A WARM FRONT. HUMIDITY LOOKS TO BE HELD IN CHECK THANKS TO DRIER LOW LEVEL AIR IN PLACE. NO EXPECTING MUCH IN THE WAY OF CONVECTION AS WARM 850MB TEMPS LOOK TO KEEP A CAP IN PLACE AND LIMIT STORM POTENTIAL. TEMPS WILL RANGE FROM THE LOWER TO MID 90S WITH THE WARMEST READINGS ACROSS THE SOUTH HALF. BY FRI NGT AND INTO SAT...A COMPACT S/WV WILL DROP SE OUT OF THE SOUTHERN PLAINS AND LIKELY HAVE SOME SORT OF STORM COMPLEX ASSOCIATED WITH IT. MODELS HAVE BEEN CONSISTENT IN SHOWING THIS FEATURE AND CONTINUE TO DO SO. IT APPEARS THAT AFTER MIDNIGHT FRI NGT...THE NW/N HALF OF THE AREA COULD SEE THE REMNANTS OF A COMPLEX MOVE ACROSS THE AREA. MODEL DATA ALSO AGREE THAT LINGERING PRECIP CHANCES WILL EXIST ON SAT DUE TO CONTINUED EFFECTS OF LIFT AND LOW LEVEL MOISTURE CONVERGENCE. DUE TO THIS...HIGH END CHANCE TO LIKELY POPS WILL EXIST FOR THOSE TWO PERIODS. AT THIS TIME...ITS DIFFICULT TO SAY WHAT SORT OF RISK THIS ACTIVITY MAY POSE TO THE CWA. AT A MINIMUM IT SEEMS LIKE SOME STRONG STORMS AND HEAVY RAIN WILL BE POSSIBLE. HOWEVER...WILL NOT MENTION ANY RISK AT THIS TIME IN OFFICIAL PRODUCTS AND SEE HOW THINGS PLAY OUT OVER THE NEXT FEW MODEL RUNS. AS FOR TEMPS...HIGHS SAT LOOK TO BE HELD IN CHECK QUITE A BIT AS PRECIP/CLOUDS WILL KEEP READINGS QUITE A BIT BELOW AVG. FOR SAT NGT THROUGH WED...THERE WILL LIKELY BE SOME LINGERING PRECIP CHANCES FOR SAT NGT INTO SUN AS A WEAK SFC FRONT WILL BE CLOSE TO THE AREA AND SOME LINGERING MID LEVEL SHEAR STILL EXISTS FROM THE LEFT OVER TROUGH AXIS. THIS SFC FRONT MAY BRIEFLY BRING SOME LOWER DEWPTS TO THE AREA SUN INTO MON AND HELP TAKE THE EDGE OFF HUMIDITY. HOWEVER...THIS BOUNDARY LOOKS TO WASH OUT AND MORE NORMAL SUMMERTIME TEMPS/HUMIDITY SHOULD RETURN. THE PATTERN COULD BRING SOME SURPRISES AS IT WILL STILL HAVE SOME HINTS OF A NW FLOW REGIME. /CME/ && .AVIATION...STUBBORN IFR STRATUS PLAGUING KGTR WHICH SHOULD PERSIST FOR A FEW MORE HRS BEFORE THINGS TREND VFR. ELSEWHERE VFR CONDS TO PREVAIL WITH JUST A LOW CHANCE OF SEEING SOME IFR CIG AT HBG/PIB/MEI THRU 13Z. ANOTHER ROUND OF SHRA/TSRA WL LIKELY IMPACT MOST AREAS AFTER 17Z TODAY W/THIS ACTIVITY ON THE DOWNWARD TREND THIS EVENING/ OVRNGT. SFC WINDS WL BE GENERALLY OUT OF THE W/THRU THE PERIOD AND MAY OCCASIONALLY GUST THIS AFTN. GENERALLY QUIET WX XPCTD OVRNGHT. /BK/ && .PRELIMINARY POINT TEMPS/POPS... JACKSON 91 72 93 67 / 50 17 14 6 MERIDIAN 91 72 93 64 / 56 17 14 7 VICKSBURG 91 70 93 66 / 46 18 14 6 HATTIESBURG 91 73 94 69 / 61 22 22 14 NATCHEZ 90 72 91 69 / 41 26 21 12 GREENVILLE 89 71 91 66 / 50 15 4 7 GREENWOOD 90 70 90 64 / 50 15 5 6 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...NONE. LA...NONE. AR...NONE. && $$ BK/CME
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1221 AM CDT WED JUL 24 2013 .UPDATE... ISSUED AT 708 PM CDT TUE JUL 23 2013 AS OF 00Z KUEX INDICATES DEEP CONVECTION HAS MOVED SOUTH OF OUR CWA CLOSER TO THE I-70 CORRIDOR. IN ADDITION...DEEP CONVECTION OVER THE HIGH PLAINS OF WESTERN NEBRASKA IS MOVING MORE SOUTHERLY AND IF THESE TRENDS CONTINUE...SHOULD MISS OUR CWA TO THE WEST. BARRING ADDITIONAL SHOWER AND THUNDERSTORM DEVELOPMENT TO OUR NORTHWEST THIS EVENING AND TONIGHT...DRY CONDITIONS SHOULD PREVAIL AND AS A RESULT...POPS HAVE BEEN REMOVED FROM THE FORECAST AND ASSOCIATED SEVERE WEATHER WORDING REMOVED FROM THE HWO. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 400 PM CDT TUE JUL 23 2013 THE MAIN FOCUS FOR THIS EVENING/TONIGHT IS ON TSTM POTENTIAL. CONVECTION WAS ONGOING FOR MUCH OF THE DAY TODAY BUT IN THE LAST FEW HOURS THIS ACTIVITY HAS DISSIPATED. THE CAP REMAINS STRONG ACROSS OUR SOUTHERN ZONES WITH THE MAIN BOUNDARY/WARM FRONT ORIENTED ACROSS SOUTHERN KANSAS. THIS BEING SAID...REMNANT OUTFLOW BOUNDARIES/DIFFERENTIAL HEATING BOUNDARIES RESIDE ACROSS OUR CWA WITH THE NORTHERN TWO THIRDS OF OUR CWA REMAINING UNCAPPED. ONE SUCH BOUNDARY FOR OUR CWA IS ORIENTED NEAR THE NEB/KS STATE LINE AND CANNOT RULE OUT STRONG/SEVERE STORMS IN THIS AREA AS BOUNDARY SAGS SOUTH WITH INSTABILITY ON THE ORDER OF 2000 TO 3000 J/KG AND GOOD SHEAR IN OUR NW FLOW REGIME. FARTHER NORTH...A HIT OR MISS SHOWER/STORM CANNOT BE RULED OUT AS SUBTLE SHORTWAVE TROUGHS TRANSLATE SE ACROSS THE INTERIOR CONUS. FARTHER UPSTREAM...NEW STORMS ARE DEVELOPING ACROSS WESTERN SOUTH DAKOTA IN A SIMILAR MANNER AS 24HRS AGO...BUT CONFIDENCE IS NOT HIGH THAT THESE STORMS WILL SUSTAIN INTO THE OVERNIGHT HOURS TO IMPACT OUR REGION...BUT WILL NEED TO MONITOR. THE HRRR TRACKS THIS ACTIVITY TO THE WEST OF OUR CWA. ASIDE FM THE HIT OR MISS STORM POTENTIAL...WE ARE LOOKING AT FAIRLY SEASONAL CONDITIONS OR PERHAPS A FEW DEGREES COOLER THAN NORMAL BOTH TONIGHT AND WEDNESDAY. A SFC RIDGE AXIS WILL BUILD TO THE SOUTHWEST FM THE UPPER MIDWEST AND COOLER AIR WILL BACK IN FM THE NORTHEAST. SFC DPS DROP SEVERAL DEGREES AND OVERNIGHT LOWS SHLD AVERAGE IN THE UPPER 50S TO LOW 60S. MODELS INDICATE SOME POTENTIAL FOR SOME LOW CLOUDS AROUND TONIGHT/EARLY WEDNESDAY...MAINLY IN KS. THERE ARE SOME MODEL DIFFERENCES ON HIGHS FOR WEDNESDAY BUT WITH THE AIRMASS MORE SIMILAR TO TODAY...WILL AIM FOR HIGH TEMPS IN THE MID/UPPER 80S. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 400 PM CDT TUE JUL 23 2013 OVER THE PAST SEVERAL DAYS...MORE AND MORE OF THE CWA HAS GRADUALLY RECEIVED AT LEAST MINIMAL AMOUNTS OF MEANINGFUL MEASURABLE RAIN AFTER A VERY DRY START TO THE MONTH...AND THIS TREND OF VARIOUS...HIT-AND-MISS RAIN CHANCES IN WHICH PARTS OF THE AREA SEE DECENT PRECIPITATION WHILE OTHERS LARGELY MISS OUT IS EXPECTED TO CONTINUE THROUGH THE FORECAST PERIOD. AT THIS TIME...ALL RAIN CHANCES OVER THIS 6-DAY PERIOD HAVE BEEN CAPPED AT NO MORE THAN 30-50 PERCENT...UNTIL/UNLESS CONFIDENCE INCREASES. ALTHOUGH VERY SUBJECT TO CHANGE...THE THURS/THURS NIGHT AND SUN NIGHT/MONDAY TIME FRAMES CURRENTLY CONTAIN THE OVERALL-HIGHEST COVERAGE OF 30+ POPS. REGARDING SEVERE WEATHER PROSPECTS...ITS AGAIN MUCH THE SAME STORY AS ALTHOUGH ITS QUITE POSSIBLE...IF NOT LIKELY...THAT AT LEAST A FEW SEVERE STORMS FLARE UP FROM TIME TO TIME...THERE IS NO DEFINITIVE SETUP OF HEIGHTENED CONCERN EVIDENT AT THIS TIME...AND THUS HAVE REFRAINED FROM SPECIFYING ANY PERIODS IN THE HAZARDOUS WEATHER OUTLOOK. ON A POSITIVE NOTE FOR MOST FOLKS...THERE IS PRETTY HIGH CONFIDENCE IN A CONTINUED SLIGHTLY BELOW NORMAL TEMPERATURE REGIME...WITH HIGHS ON MOST DAYS AVERAGING 3-8 DEGREES BELOW AVERAGE LATE-JULY VALUES. STARTING OFF WEDNESDAY EVENING/NIGHT...SEASONABLY STRONG NORTHWEST FLOW REMAINS IN PLACE OVER THE CENTRAL PLAINS...BETWEEN RIDGING CENTERED OVER THE NV/CA/UT/AZ BORDER AREA...AND A BROAD LONGWAVE TROUGH OVER THE EASTERN CONUS...WHILE A SHORTWAVE TROUGH DIVES SOUTH-SOUTHEAST ACROSS MANITOBA/SASKATCHEWAN. WITHIN THE LOCAL FLOW...A LOW-AMPLITUDE SHORTWAVE TROUGH IS PROGGED TO RIDE EASTWARD ALONG THE KS/NE BORDER OUT OF NORTHEAST CO AS THE NIGHT WEARS ON. ALTHOUGH INSTABILITY APPEARS PRETTY MINIMAL LOCALLY...HAVE EXPANDED SLIGHT CHANCES FOR STORMS ACROSS MUCH OF THE WESTERN HALF OF THE CWA POST-MIDNIGHT...WHILE LEAVING THE EVENING HOURS DRY...AT LEAST FOR NOW. MADE LITTLE CHANGE OT LOW TEMPS...WITH MID 60S MOST AREAS. THURSDAY/THURSDAY NIGHT...POP-WISE MADE LITTLE CHANGE FROM PREVIOUS FORECAST WITH A BROAD COVERAGE OF 30 POPS AND SOME 40S- 50S MAINLY FOCUSED IN SOUTHERN ZONES. ALOFT...ITS THE SAME OLD THEME...WITH SUBTLE EMBEDDED SHORTWAVE TROUGHS WORKING OVER OR NEAR THE CWA IN NORTHWEST FLOW...WHILE A STRONGER SHORTWAVE TROUGH DROPS OUT OF CANADA INTO THE NORTHERN MN AREA. NOT SURPRISINGLY...MODEL QPF FIELDS ARE OVER THE PLACE...WITH THE ECMWF HITTING THE DAYTIME HOURS A LITTLE HARDER AND THE GFS THE NIGHT. TEMP-WISE...WITH A RETURN TO MORE SOUTHERLY WINDS...NUDGED UP HIGH TEMPS A LITTLE FROM PREVIOUS PER MET/MAV GUIDANCE BLEND...BUT STILL ONLY MID 80S IN MOST AREAS. FRIDAY/FRIDAY NIGHT...CONTINUED 20-30 POPS CWA-WIDE THIS ENTIRE TIME...ALTHOUGH LARGE SCALE SUPPORT WANES A BIT FRIDAY NIGHT AS THE AFOREMENTIONED GREAT LAKES REGION SHORTWAVE TROUGH CLOSES OFF AND STARTS TO SLOWLY EDGE FARTHER EAST. IN THE WAKE OF A PASSING COLD FRONT AND RETURN TO NORTHEAST BREEZES...HAVE HIGHS BACK DOWN IN THE LOW 80S MOST NEB ZONES...AND MID 80S IN KS. SATURDAY/SATURDAY NIGHT...CAME VERY CLOSE TO LEAVING THE CWA VOID OF THUNDERSTORM MENTION DURING THE DAY PER PREVIOUS FORECAST...BUT WENT AHEAD AND BROUGHT SOME SLIGHT POPS BACK INTO PARTS OF THE SOUTHWEST 1/2 MAINLY PER THE 12Z ECMWF. SATURDAY NIGHT...HINTS OF A SUBTLE SHORTWAVE TROUGH CONTINUE TO SUPPORT SLIGHT POPS AREA- WIDE. HIGH TEMPS SATURDAY AGAIN LOW-MID 80S. SUNDAY/SUNDAY NIGHT...THE LARGE-SCALE FLOW STARTS TO TURN LEGITIMATELY MORE ZONAL VERSUS NORTHWESTERLY...IN THE WAKE OF THE GREAT LAKES CLOSED LOW LIFTING BACK NORTHEAST INTO CANADA...BUT THE TRAIN OF LOW AMPLITUDE DISTURBANCES INTO THE CENTRAL PLAINS CONTINUES...AND HAVE SLIGHT POPS IN NEARLY ALL AREAS DURING THE DAY...FOLLOWED BY 30-40 POPS SUNDAY NIGHT. MONDAY/MONDAY NIGHT...CONTINUED QUASI-ZONAL FLOW WITH EMBEDDED DISTURBANCES...AND HAVE AT LEAST SLIGHT POPS THROUGHOUT THIS 24 HOURS ALL AREAS...AND HIGHER VALUES CURRENTLY FOCUSED DURING THE DAY. TEMP-WISE...LOW 80S NORTHEAST TO NEAR 90 SOUTHWEST. TUESDAY...HAVE KEPT IT DRY FOR NOW...BUT ITS NO GUARANTEE TO STAY THAT WAY...AS THERE IS OVERALL LITTLE CHANGE IN THE PATTERN. POSSIBLY IN RESPONSE TO CLIMATOLOGY CARRYING MORE WEIGHT WITH MODEL GUIDANCE AT THIS TIME RANGE...HIGHS TUESDAY ARE PRELIMINARILY ADVERTISED TO BE A TOUCH WARMER THAN PREVIOUS DAYS...WITH MID 80S NORTHEAST TO LOWER 90S SOUTHWEST. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1220 AM CDT WED JUL 24 2013 OTHER THAN A FEW MID LEVEL CLOUDS DRIFTING THROUGH THE AREA THE SKIES WILL BE PRIMARILY CLEAR THROUGH THE PERIOD. A SURFACE HIGH PRESSURE SYSTEM SETTLES INTO THE AREA AND WINDS ARE EXPECTED TO BE LIGHT AND VARIABLE. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM...FAY LONG TERM...PFANNKUCH AVIATION...JCB
AREA FORECAST DISCUSSION
NWS ELKO NV
903 PM PDT TUE JUL 23 2013 .SYNOPSIS...MONSOON MOISTURE IS IMPACTING NEVADA TODAY AND TOMORROW PROVIDING INCREASING CLOUDS...ENHANCED CHANCES FOR THUNDERSTORMS. THUNDERSTORMS ARE LIKELY ACROSS CENTRAL NEVADA THIS AFTERNOON AND EVENING WHERE SOME WILL PRODUCE HEAVY RAINFALL. MORE CONVECTION IS POSSIBLE TOMORROW AFTERNOON. && .UPDATE...MOSTLY CLOUDY TO CLOUDY SKIES CAN BE SEEN ACROSS THE ENTIRE FORECAST AREA. PRECIPITATION AT THIS TIME IS LIMITED TO PARTS OF THE WESTERN CWA. HAVE MASSAGED OVERNIGHT POPS BASED ON LATEST MODEL GUIDANCE...BUT HAVE KEPT AT LEAST ISOLATED THUNDER THROUGH THE OVERNIGHT. ALL PRODUCTS WILL BE SENT SHORTLY. && .PREV DISCUSSION... /ISSUED AT 318 PM / SHORT TERM...THIS AFTERNOON THROUGH THURSDAY. A REMNANT UPPER LOW OVER THE SILVER STATE AND DEEP MOISTURE NEARING 200 PERCENT OF NORMAL NEAR LAS VEGAS ARE NEARLY COINCIDENT WITH VISIBLE SATELLITE IMAGERY SHOWING CUMULUS CLOUDS. THE MOISTURE ALONG WITH DIFFERENTIAL HEATING ZONES...WILL LEND ITSELF TOWARDS RIPE CONVECTION. THE RADAR HAS ALREADY PINGED INTO A NUMBER OF THUNDERSTORMS TODAY WHICH IS CONSISTENT WITH THE NAM12 AND THE HRRR FOR ENHANCED CAPE AND LIFTED INDICES. MORE THUNDERSTORMS EXPECTED TOMORROW AFTERNOON. LONG TERM...THURSDAY NIGHT THROUGH NEXT TUESDAY. THE MODELS ARE IN FAIRLY GOOD AGREEMENT THROUGH TUESDAY. THE GENERAL SCENARIO IS FOR ABOVE-NORMAL TEMPERATURES TO CONTINUE. THE RIDGE OF HIGH PRESSURE RESPONSIBLE FOR THE LATEST STRING OF VERY WARM TEMPERATURES WILL REMAIN STRONG THROUGH EARLY FRIDAY THEN BEGIN TO GET SUBDUED BY THE INFUSION OF A LOW PRESSURE SYSTEM CROSSING EAST ACROSS THE SIERRAS FOLLOWED BY A STRONGER UPPER LOW MOVING SOUTH FROM THE PACIFIC NORTHWEST REGION. THE UPPER LOW WILL SLOWLY BEAR DOWN AND FLATTEN THE RIDGE BY THE WEEKEND. SOME DAYTIME TEMPERATURES WILL FALL INTO THE 80S OVER THE WEEKEND AND INTO EARLY NEXT WEEK. MODELS ARE INDICATING A VERY UNSTABLE AIR MASS OVER CENTRAL NEVADA FOLLOWING THE SURGE OF MOISTURE EXPECTED TODAY AND TOMORROW. DOWNDRAFT CAPE VALUES SOUTH OF HIGHWAY 50 ARE GREATER THAN 1500 J/KG THROUGH SATURDAY. PRECIPITABLE WATER VALUES ARE APPROACHING ONE INCH SOUTH OF HIGHWAY 50. THE PROSPECT OF FLASH FLOODING FROM THUNDERSTORM TRAINING ACROSS CENTRAL NEVADA MAY LINGER THROUGH SATURDAY DUE TO THE LIGHT WINDS ALOFT...ESPECIALLY OVER THE RECENT BURN AREAS OF NORTHERN NYE AND WHITE PINE COUNTIES...SPECIFICALLY THE WHITE PINE FIRE AND THE BLACK FIRE. HUMBOLDT COUNTY WILL SEE THE LEAST AMOUNT OF THUNDERSTORM ACTIVITY THROUGHOUT THE LONG TERM PERIOD AND OVERNIGHT THUNDERSTORMS WILL BE PRIMARILY CONFINED TO THE SOUTHERN HALF OF THE FORECAST AREA THROUGH FRIDAY NIGHT...THEN THE EASTERN HALF SATURDAY AND SUNDAY AS A SHORTWAVE LOW TO THE NORTH NUDGES THE MOISTURE AXIS EAST. THE SHOW MAY BE OVER BY TUESDAY AS THE DEVELOPING PACIFIC TROUGH PROMISES TO SCOUR THE MOISTURE OUT OF THE GREAT BASIN. AVIATION...VFR CONDITIONS CAN BE EXPECTED THROUGH WEDNESDAY. THUNDERSTORM ACTIVITY IS EXPECTED TO AFFECT KELY AND KTPH THROUGH EARLY THIS EVENING. ISOLATED THUNDERSTORMS MAY AFFECT KELY AND KTPH OVERNIGHT. THUNDERSTORM ACTIVITY IS EXPECTED TO AFFECT KWMC KEKO KELY AND KTPH WEDNESDAY AFTERNOON AS THE MOISTURE FLUX INCREASES ACROSS THE NORTH. BRIEF HEAVY RAINS AND STRONG GUSTY WINDS ARE POSSIBLE WITH THESE STORMS. FIRE WEATHER...A VERY UNUSUAL PATTERN HAS BEEN IN PLACE FOR THE PAST TWO WEEKS. THIS UPPER LEVEL DISTURBANCE THAT IS CURRENTLY OVER THE WESTERN GREAT BASIN...ORIGINALLY CAME FROM THE MIDWEST...AKA...BACK EAST...WHERE A STRONG HIGH DEVELOPED CAUSING THIS LOW TO RETROGRADE. THE SYSTEM HAS TAPPED INTO A FETCH OF MONSOON MOISTURE. THE PWS OVER LAS VERY WERE ALMOST 200 PERCENT OF NORMAL FROM THIS MORNINGS 12Z SOUNDING...REAL DATA NOT MODEL DATA. TAKING THE GENESIS OF THIS PATTERN IN COMBINATION WITH AN UNSTABLE AIR MASS WILL RESULT IN SCATTERED TO NUMEROUS THUNDERSTORMS CAPABLE OF PRODUCING HEAVY RAIN ACROSS MUCH OF CENTRAL NEVADA. STORMS WILL BE SLOW MOVING AND MAY TREK OVER THE SAME LOCATIONS...RESULTING IN ENHANCED RAINFALL AMOUNTS. && .LKN WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH UNTIL 5 AM PDT WEDNESDAY FOR NORTHEASTERN NYE COUNTY...NORTHWESTERN NYE COUNTY...SOUTHERN LANDER COUNTY AND SOUTHERN EUREKA COUNTY...WHITE PINE COUNTY. && $$ 86/93
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
140 AM EDT WED JUL 24 2013 .SYNOPSIS... ADDITIONAL SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL STILL BE POSSIBLE UNTIL A STRONG COLD FRONT PASSES THROUGH OVERNIGHT. MUCH DRIER AND COOLER WEATHER WILL SETTLE IN FOR WEDNESDAY THROUGH FRIDAY COURTESY OF CANADIAN HIGH PRESSURE. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... 730 PM UPDATE... FRONTAL BNDRY IS DROPPING THRU CANADA ATTM. PRE-FRONTAL TROF IS POISED TO CROSS THE GREAT LKS WITH SHOWERS/TSTMS DVLPNG JUST AHD OF IT, IN COMBINATION WITH MCV ROTATING THRU WRN NY. A BROKEN LINE OF CONVECTION IS LOCATED ACRS SRN ONTARIO WELL AHD OF MAIN CDFNT. AS IT STANDS NOW, DO NOT EXPECT THIS LINE OF CONVECTION TO SUSTAIN ITSELF MUCH LONGER WITH LOSS OF DIURNAL HTG AND INSTABILITY ON THE WANE. HWVR, CANNOT RULE OUT SCTD SHOWERS/ISOLD THUNDER AS THIS PRE-FRONTAL TROF/CDFNT MV THRU CWA OVRNGT. LATEST HRRR SHOWS LINE OF CONVECTION CROSSING ACRS SRN SXNS OF CWA OVRNGT TONIGHT BUT AS OF 23Z IT IS NOT EVEN CLOSE TO BEING IN LINE WITH REALITY. THUS, HV DISCOUNTED IT AND HV SIDED MORE WITH HIRES ARW WHICH SHOWS VRY ISOLD CONVECTION THRU THE NIGHT WITH SOME SHOWERS EXPECTED AFT 06Z WITH MAIN COLD FRONT. HV UPDATED SKY GRIDS INITIALLY WITH MOCLDY EXPECTED THRU 02Z ACRS WRN ZONES AND DIMINISHING WITH SUNSET. PCLDY-MOCLDY WL EXIST THRU MOST OF THE NIGHT, ESPECIALLY IN AREAS DOWNWIND OF LK ONTARIO AS MOISTURE GETS TRAPPED UNDER SUBSIDENCE INVERSION AFT 08Z. HV KEPT MENTION OF ISOLD SHOWERS BUT MAY BE LOOKING AT MORE OF A DRIZZLE/FOG SCENARIO UNDER LOW CLD CVR. NO OTHER CHGS MADE TO MINS/WINDS AT THIS TIME AS ALL LOOKS TO BE ON TARGET. PREV DISCUSSION BLO... 230 PM UPDATE... UPPER WAVE EXITED THIS MORNING...TAKING AWAY THE DEEPER MOISTURE WITH IT. HOWEVER...WE STILL HAVE A FEW FEATURES TO DEAL WITH BEFORE HIGH PRESSURE BUILDS IN AND SHUTS THINGS DOWN. LOOSELY- DEFINED SURFACE LOW HAS MOVED TO THE MID HUDSON VALLEY WITH A FRONTAL BOUNDARY /INITIAL COLD FRONT/ DRAGGING BEHIND IT. ASSOCIATED LOW LEVEL CONVERGENCE ZONE HAS YIELDED SCATTERED SHOWERS AND AN OCCASIONAL LIGHTNING STRIKE GENERALLY FROM THE CATSKILLS TO WYOMING VALLEY...NOW SHIFTING SOUTHEAST THROUGH THE POCONOS. ACTIVITY PROBABLY WOULD BE BETTER ORGANIZED IF IT OUR REGION HAD NOT BEEN IN THE UNFAVORABLE LEFT ENTRANCE REGION OF A DEPARTING JET THIS MORNING TO EARLY AFTERNOON. MEANWHILE...SECONDARY STRONG COLD FRONT IS IGNITING CONVECTION IN LOWER MICHIGAN. THIS WILL TRAVEL THROUGH LATE TONIGHT WITH A BATCH OF SCATTERED SHOWERS. AT THIS TIME...FIGURING LOSS OF DIURNAL HEATING AND LOWERING PWATS WILL PROBABLY PREVENT THUNDER AFTER MIDNIGHT...NOT COMPLETELY IMPOSSIBLE BUT SHOULD BE THE EXCEPTION NOT THE RULE. HOWEVER...BETWEEN THE TWO FRONTS...WE HAVE A SHORTWAVE RUNNING OUT AHEAD OF THE SECONDARY FRONT. THIS IS CURRENTLY PRODUCING CONVECTION FROM EASTERN OHIO TO JUST NORTH OF THE WESTERN TIP OF LAKE ONTARIO. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE FIGURED THIS EVENING FROM THIS ACTIVITY...FOR AT LEAST THE NORTHWEST TO CENTRAL PORTIONS OF OUR AREA. WE WILL NEED TO WATCH THE LOCALIZED AREAS THAT RECEIVED HEAVY RAINFALL IN THE LAST 18-24 HOURS JUST IN CASE...BUT AT THIS POINT NOT EXPECTING WATER PROBLEMS BECAUSE OF DECREASING PRECIPITABLE WATER VALUES...LIMITED GAPPY COVERAGE TO THE CONVECTION...AND THE PROGRESSIVE NATURE OF INDIVIDUAL CELLS THIS EVENING INTO OVERNIGHT. && .SHORT TERM /6 AM THIS MORNING THROUGH FRIDAY/... 1 PM UPDATE... LONG STORY SHORT...LARGE CANADIAN HIGH PRESSURE BUILDS IN WITH DRY AND COOL AIR MASS. THIS WILL INCLUDE THE COOLEST TEMPERATURES OF JULY 2013 BY EARLY THURSDAY MORNING. ON THE FRONT EDGE OF THE BUILDING HIGH...SOME LOW LEVEL MOISTURE WILL BE TRAPPED UNDER DEVELOPING SUBSIDENCE INVERSION EARLY WEDNESDAY. GIVEN THE FAIRLY SHALLOW NATURE OF IT...EXPECTING CLOUDS AND PERHAPS A COUPLE SPRINKLES FOR A TIME EARLY WEDNESDAY MORNING...BEFORE VERY DRY AIR MASS BECOMES FULLY REALIZED LATE MORNING THROUGH WEDNESDAY AFTERNOON...ERADICATING CLOUDS VIA COLD AIR ADVECTION AND MIXING DOWN OF VERY DRY AIR FROM MID LEVELS. PRECIPITABLE WATER VALUES DIVE TO LESS THAN A HALF INCH BY LATE WEDNESDAY AFTERNOON. THIS IS NEARLY 2 STANDARD DEVIATIONS BELOW NORMAL FOR JULY. EXCEPT FOR PERHAPS THE LOWEST ELEVATIONS OF DELAWARE VALLEY IN PIKE COUNTY PA...HIGHS WEDNESDAY SHOULD BE LIMITED TO UPPER 60S TO MID 70S FOR CNY AND 70S FOR NEPA. THE COOL FRESH DAY WITH NORTHWEST WINDS GUSTING TO 15-20 MPH...WILL BE FOLLOWED BY QUICK DECOUPLING OF WINDS WEDNESDAY NIGHT AS CENTER OF HIGH SHIFTS FROM WESTERN GREAT LAKES TO EASTERN GREAT LAKES/QUEBEC/ONTARIO. RADIATIONAL COOLING WILL EASILY YIELD THE COOLEST NIGHT OF THIS MONTH...UPPER 40S TO MID 50S...COOLEST IN SHELTERED VALLEYS OF THE TWIN TIERS AND WESTERN CATSKILLS AND MOHAWK VALLEY. CAVEAT ON THIS IS THAT WITH 850MB TEMPERATURES OF ONLY 6-8 DEGREES CELSIUS...WE MAY ACTUALLY GET SOME LAKE EFFECT CLOUDS COMING FROM LAKE ONTARIO TO SOME PARTS OF FINGER LAKES AND CENTRAL SOUTHERN TIER REGIONS. TEMPERATURES WILL BE VERY SENSITIVE TO RADIATIONAL COOLING SET UP AND THUS CLOUD LAYER DETAILS. HIGH PRESSURE CENTER WILL TRAVEL ROUGHLY DOWN THE SAINT LAWRENCE SEAWAY THURSDAY...THEN TO CANADIAN MARITIME PROVINCES FRIDAY...YET OVERALL THE HIGH PRESSURE WILL REMAIN DOMINANT OF OUR WEATHER. I WAS ABLE TO REMOVE LINGERING SLIGHT CHANCE OF A SHOWER THAT WAS IN OUR FAR SOUTHEASTERN ZONES THURSDAY. BY FRIDAY...SOME EASTERLY LOW LEVEL FLOW UNDER THE HIGH COULD POTENTIALLY ATTEMPT TO BRING IN MARINE LAYER MOISTURE AGAINST THE POCONOS/CATSKILLS...SO I PLACE A SLIGHT CHANCE OF A SHOWER THERE BUT OTHERWISE STILL DRY AREAWIDE. OVERALL...AT LEAST A SURFACE RIDGE WILL KEEP CONTROL FOR MOST OF THE REGION. HIGHS FRIDAY BACK UP TO NEAR CLIMATOLOGY...YET WITH DEWPOINTS STILL VERY COMFORTABLE IN THE 50S. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... 330 PM EDT UPDATE... THE MAIN FOCUS OF THE EXTENDED FORECAST IS A STRONG UPPER LEVEL LOW MOVING SOUTH FROM CANADA INTO THE CENTRAL PLAINS THURSDAY AND THEN PROPAGATE EASTWARD AND AFFECT THE CWA ON SATURDAY. THE BEST CHANCE FOR SHOWERS AND THUNDERSTORMS WILL BE ON SUNDAY AS FRONT PUSHES THROUGH THE REGION. INCREASED POPS ON SUNDAY AS CONFIDENCE HAS INCREASED. MODELS INDICATE THAT PWAT VALUES WILL INCREASE ABOVE 1.5 INCHES SO HEAVY RAIN ATTENDANT WITH THE FRONT MAY BE POSSIBLE. THE COLD FRONT WILL BRING COOLER TEMPS AND MUCH DRIER AIR TO CENTRAL NY AND NORTHEAST PA. WITH THIS DRIER AIR THERE SHOULD BE A COUPLE OF DRY PERIODS INTO THE NEW WEEK UNTIL ANOTHER SYSTEM PUSHES THROUGH MID WEEK. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... FNTL BNDRY MVG INTO THE FCST AREA ATTM WITH CONV MVG AHD OF THE FNT...AND GNRLY EAST OF THE TAF SITES. SOME BRIEF MVFR CIGS AND VSBYS BHD THE CONV...FLWD BY A RETURN TO VFR ALL STATIONS LATE TNGT AS MUCH DRIER AIR MVES INTO THE REGION. VFR CONDS WILL THEN REMAIN THRU THE END OF THE PD AS THE NW FLOW OF DRY AIR CONTS. WINDS WILL GO LGT AFT 00Z AS A SMALL SC HI BLDS IN AND LWR LVL DECPLS. .OUTLOOK... WED NGT/THU/...VFR FRI/SAT/SUN...CHANCE OF SCATTERED MVFR CIGS/VSBYS IN DEVELOPING SHRA/TSRA ACTIVITY. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...MDP NEAR TERM...MDP/PVN SHORT TERM...MDP LONG TERM...KAH AVIATION...CMG/DGM
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1136 PM CDT TUE JUL 23 2013 .UPDATE... ISSUED AT 1136 PM CDT TUE JUL 23 2013 THINK THAT ANY PRECIP WILL BE FROM THE NEXT WEAK SHORTWAVE CURRENTLY OVER SOUTHERN CANADA SO ADJUSTED POPS A BIT TO DELAY ANY PRECIP UNTIL AFTER 09Z. ADJUSTED CLOUDS A BIT ALSO. UPDATE ISSUED AT 928 PM CDT TUE JUL 23 2013 ONLY MINOR UPDATES AS ONE WEAK SHORTWAVE BRINGS STORMS INTO SD AND THE NEXT SHORTWAVE STILL WELL UPSTREAM OVER CANADA. CONTINUE TO THINK THAT ANY PRECIP WILL BE WELL AFTER MIDNIGHT. LOWERED TEMPS JUST A BIT IN THE FAR EASTERN COUNTIES AS DEW POINTS HAVE BEEN LOWER IN THAT AREA. UPDATE ISSUED AT 627 PM CDT TUE JUL 23 2013 NO MAJOR CHANGES FOR THIS UPDATE AS THE CONVECTION IN CENTRAL ND IS ON TRACK TO MISS OUR SOUTHWESTERN COUNTIES. THE BETTER CHANCES FOR ANY PRECIP WILL BE AFTER MIDNIGHT TONIGHT. TEMPS SHOULD BOTTOM OUT IN THE 50S. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT) ISSUED AT 309 PM CDT TUE JUL 23 2013 MAIN FORECAST CHALLENGE REMAINS PCPN CHANCES OVER THE NEXT FEW DAYS. MODELS SEEM TO BE IN BETTER AGREEMENT ON THE DETAILS THIS TIME AROUND WHICH MATCH UP PRETTY WELL WITH FORECAST CONTINUITY. THEREFORE DO NOT PLAN MANY CHANGES TO THE SHORT TERM. QUITE A BIT OF CUMULUS FORMED ACROSS THE AREA AGAIN TODAY WHICH LIKELY HELPED TO HOLD DOWN TEMPS A LITTLE. EXPECT THE CUMULUS TO THIN OUT THIS EVENING. THE MID AND HIGH LEVEL CLOUDS ASSOCIATED WITH AREA OF PCPN OVER NORTHWEST ND SHOULD DRIFT INTO PORTIONS OF THE FA. ANY ACTUAL PCPN SHOULD TRACK FROM NORTHWEST ND DOWN INTO NORTHEAST SD TONIGHT. LATEST VERSION OF THE RAP SEEMS TO SHOW THIS WELL. WILL LEAVE INHERITED PCPN CHANCES ACROSS THE SOUTHWEST FOR LATE TONIGHT BASICALLY AS IS. PRETTY DRY SFC DEW POINT READINGS ESPECIALLY IN THE EAST SO CUT BACK A LITTLE ON MIN TEMPS THERE. FOR WED THERE ARE NOT A LOT OF CHANGES FROM TODAY. STILL IN NW FLOW WITH WEAK EMBEDDED IMPULSES. MODELS ALL SEEM CONSISTENT IN SHOWING SOME LIGHT PCPN ACROSS THE AREA. THESE CHANCES SHOULD SHIFT INTO NORTHWEST MN WED NIGHT. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 309 PM CDT TUE JUL 23 2013 BY THU THE NEXT SFC COLD FRONT WILL SWING THRU THE FA WITH A LITTLE STRONGER UPPER LEVEL DISTURBANCE. THIS WILL PROBABLY BE THE TIME PERIOD WITH THE BEST CHANCE FOR PCPN ALTHOUGH AMOUNTS WILL BE PRETTY LIGHT. WILL LEAVE THU NIGHT DRY. STILL HAVE SOME QUESTIONS ABOUT PCPN CHANCES AGAIN BY FRI. MODELS ARE INDICATING A SUBSTANTIAL PIECE OF SHORTWAVE ENERGY DROPPING THROUGH WITH CHILLY 500MB TEMPS. LEFT SOME LOW CHANCES FOR PCPN IN THE EAST. FOR FRI NIGHT THROUGH TUE...THE PERIOD WILL BEGIN WITH TEMPS BELOW NORMAL AND DRY WEATHER...WITH COOL CANADIAN HIGH PRESSURE IN CONTROL. TEMPS AND MOISTURE PROFILES WILL INCREASE BY EARLY NEXT WEEK...WITH A CHANCE FOR SHOWERS AND STORMS WITH MORE ZONAL FLOW ALOFT. MOST AREAS COULD REMAIN DRY THROUGH MONDAY...WITH DRY AIR IN PLACE INITIALLY AND IT WILL TAKE TIME TO MOISTEN COLUMN. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1136 PM CDT TUE JUL 23 2013 VFR CONDITIONS WILL CONTINUE AND ANY CONVECTION TOMORROW WILL BE HIGHLY SCATTERED AND NOT CERTAIN ABOUT HITTING TAF SITES. LIGHT AND VARIABLE WINDS WILL PICK UP OUT OF THE WEST TO NORTHWEST BY THE END OF THE PERIOD. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ UPDATE...JR SHORT TERM...GODON LONG TERM...GODON/DK AVIATION...JR
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
345 AM CDT WED JUL 24 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 345 AM CDT WED JUL 24 2013 MAIN FORECAST CONCERNS ARE ON SHOWER AND THUNDERSTORM CHANCES THURSDAY INTO THURSDAY NIGHT WITH THE POTENTIAL FOR SEVERE THUNDERSTORMS. FOCUS THEN TURNS TO TEMPERATURES FRIDAY THROUGH THE WEEKEND. LATEST WATER VAPOR IMAGERY SHOWED NORTHWEST FLOW ALOFT OVER THE UPPER MISSISSIPPI RIVER VALLEY EXTENDING NORTHWEST THROUGH SOUTHERN ALBERTA. SEVERAL EMBEDDED SHORTWAVES WERE NOTED WITHIN THE NORTHWEST FLOW. SURFACE OBSERVATIONS SHOWED HIGH PRESSURE IN CONTROL OVER THE REGION PROVIDING QUIET CONDITIONS. SOME MID AND HIGH LEVEL CLOUDS WERE MOVING ACROSS THE REGION EARLY THIS MORNING. THE CLOUDS COUPLED WITH THE DRIER AIR IN PLACE OVER THE REGION HAVE PREVENTED THE FORMATION OF FOG SO FAR. CANNOT RULE OUT SOME PATCHY FOG EARLY THIS MORNING BUT THIS SHOULD QUICKLY DISSIPATE AS MIXING INCREASES AFTER SUNRISE. THE HIGH WILL SLIDE EAST OF THE AREA TODAY AS A COLD FRONT SLIDES INTO THE EASTERN DAKOTAS AND EDGES EAST. SOME WEAK MOISTURE TRANSPORT COMBINED WITH 0-3KM MUCAPE VALUES OF AROUND 500 J/KG MAY BE ENOUGH TO PRODUCE ISOLATED SHOWERS AND THUNDERSTORMS OVER SOUTH CENTRAL MINNESOTA AND POSSIBLY PORTIONS OF SOUTHEAST MINNESOTA. THE BULK OF THIS ACTIVITY WILL LIKELY HAVE A DIFFICULT TIME MAKING IT EAST OF THE INTERSTATE 35 CORRIDOR AS IT ENCOUNTERS MUCH DRIER AIR. WILL HAVE TO KEEP A CLOSE EYE ON THIS...THE HRRR AND HI RES ARW ARE BOTH PRODUCING LIGHT PRECIPITATION ALONG THE I-35 CORRIDOR AND EDGES JUST EAST POSSIBLY IMPACTING DODGE AND MOWER COUNTIES DURING THE AFTERNOON HOURS. OTHERWISE...PLAN ON SOME PASSING MID AND HIGH LEVEL CLOUDS TODAY PROVIDING PARTLY SUNNY SKIES. ANOTHER DAY OF PLEASANT TEMPERATURES WITH HIGHS IN THE LOWER TO MID 70S. THE COLD FRONT CONTINUES TO ADVANCE SOUTHEAST TONIGHT AND BY THE LATE NIGHT HOURS LOOKS TO BE POSITIONED FROM THE ARROWHEAD OF MINNESOTA SOUTH THROUGH CENTRAL INTO SOUTHWEST MINNESOTA. IT THEN SLOWS AND STALLS AS IT EDGES INTO NORTHWEST WISCONSIN BY EARLY THURSDAY MORNING. 850 MB MOISTURE TRANSPORT EDGES INTO SOUTHEAST MINNESOTA AND WEST CENTRAL INTO NORTH CENTRAL WISCONSIN LATE TONIGHT INTO EARLY THURSDAY MORNING. ISOLATED SHOWERS AND THUNDERSTORMS COULD MOVE INTO THESE AREAS EARLY IN THE MORNING. OTHERWISE...PLAN ON PARTLY CLOUDY SKIES DURING THE OVERNIGHT HOURS WITH LOW TEMPERATURES RANGING FROM THE MID TO UPPER 50S. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 345 AM CDT WED JUL 24 2013 THE COLD FRONT SLIDES SOUTHEAST INTO THE FORECAST AREA ON THURSDAY AS A VIGOROUS UPPER LEVEL TROUGH DIVES SOUTHEAST OUT OF SOUTHERN MANITOBA/SASKATCHEWAN. SOUTH/SOUTHWEST FLOW INTO THE AREA AHEAD OF THE FRONT WILL HELP TO BOOST DEWPOINTS INTO THE MID TO UPPER 60S BY EARLY AFTERNOON. THE NAM SHOWS 0-3KM MUCAPE VALUES CLIMBING TO AROUND 3500 J/KG. THE GFS SHOWS SLIGHTLY LOWER VALUES IN THE 2000 TO 3000 J/KG RANGE. THE ECMWF ISN/T SO AGGRESSIVE...INDICATING VALUES IN THE 1200 TO 1600 J/KG RANGE. THE STRONGEST 0-6KM SHEAR LAGS BEHIND THE FRONT. HOWEVER...THERE LOOKS TO BE SUFFICIENT SHEAR TO SUPPORT A SEVERE THREAT WITH 0-6KM BULK SHEAR VALUES HOVERING IN THE 30 TO 35 KT RANGE THURSDAY AFTERNOON INTO THURSDAY EVENING. THUNDERSTORMS ARE EXPECTED TO DEVELOP ALONG THE FRONT THURSDAY AFTERNOON AND HEAD EAST SOUTHEAST ACROSS THE FORECAST AREA. SOME OF THESE STORMS MAY BECOME SEVERE WITH LARGE HAIL AND DAMAGING WINDS. WILL ALSO HAVE TO KEEP AN EYE ON THE POTENTIAL FOR AN ISOLATED TORNADO OR TWO WITH ANY STORMS THAT GO UP ALONG THE BOUNDARY. SHOWERS AND THUNDERSTORMS ARE LIKELY ACROSS THE AREA THURSDAY NIGHT AS THE COLD FRONT MOVES THROUGH. THE SEVERE WEATHER THREAT WILL LINGER THROUGH THE EVENING HOURS BUT SHOULD THEN WANE DURING THE OVERNIGHT HOURS AS CONVECTION BECOMES WIDESPREAD. THE FRONT FINALLY EXITS THE AREA BY FRIDAY AFTERNOON AS THE TROUGH DIVES INTO THE UPPER MISSISSIPPI RIVER VALLEY. AN UNSEASONABLY COOL AIRMASS MOVES INTO THE REGION IN THE WAKE OF THE FRONT. 850 MB TEMPERATURE STANDARDIZED ANOMALIES FALL INTO THE -2.0 TO -3.0 RANGE...INDICATIVE OF NEAR RECORD LOW MAX AND MIN TEMPERATURES. THE COLDEST AIR ALOFT MOVES OVER THE REGION DURING THE DAY ON SATURDAY...WHEN HIGHS WILL STRUGGLE TO GET OUT OF THE 60S. THE LOWEST HIGH TEMPERATURE AT LA CROSSE FOR JULY 27 IS 69 DEGREES...SET BACK IN 1981. THE LOWEST HIGH TEMPERATURE FOR ROCHESTER IS 64 AND WAS ALSO SET BACK IN 1981. LA CROSSE LOOKS TO BE VERY CLOSE TO REACHING THIS RECORD. CURRENT THINKING IS THAT LA CROSSE WILL SEE A HIGH OF 71...BUT IF THE GEM AND ECMWF VERIFY...THIS FORECAST HIGH TEMPERATURE COULD BE 3 TO 4 DEGREES HIGH. THE UPPER TROUGH WILL REMAIN OVER THE WESTERN GREAT LAKES THROUGH THE REMAINDER OF THE WEEKEND WITH COOL SURFACE HIGH PRESSURE IN CONTROL. PLAN ON HIGHS ON SATURDAY RANGING FROM THE MID 60S OVER FAR NORTHERN WISCONSIN TO AROUND 71 ACROSS FAR SOUTHWEST WISCONSIN. TEMPS WILL WARM A BIT ON SUNDAY AS THE TROUGH STARTS TO SHIFT EAST AND SURFACE WINDS TURN WESTERLY. HIGH TEMPERATURES ON SUNDAY ARE EXPECTED TO CLIMB INTO THE LOWER 70S UNDER MOSTLY SUNNY SKIES. THE UPPER TROUGH FINALLY PUSHES EAST OF THE REGION EARLY NEXT WEEK WITH FLOW ALOFT TURNING QUASI ZONAL. FORECAST MODELS SHOWING SOME DIFFERENCES IN THE HANDLING OF THE UPPER LEVEL PATTERN OVER THE CONUS. THE GFS TRIES TO BUILD A RIDGE OVER THE THE HIGH PLAINS WHILE THE ECMWF LEANS TOWARD AN ACTIVE QUASI ZONAL FLOW ALOFT WITH EMBEDDED SHORTWAVES BRINGING SHOWERS AND STORMS TO THE FORECAST AREA. HAVE LEANED TOWARD A MODEL CONSENSUS BLEND FOR THE FIRST PART OF THE WORK WEEK...WITH HIGHS WARMING TO MORE SEASONABLE VALUES WITH HIGHS IN THE UPPER 70S TO AROUND 80 AND CHANCES FOR SHOWERS AND THUNDERSTORMS MONDAY INTO TUESDAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1152 PM CDT TUE JUL 23 2013 BAND OF MID LEVEL CLOUDS CONTINUES TO ADVANCE SOUTHEAST TOWARD THE AREA THIS EVENING OUT OF THE DAKOTAS AND NORTHWEST MINNESOTA AHEAD OF A SHORT WAVE TROUGH. THE CLOUDS APPEAR TO BE LOOSING SOME ORGANIZATION RAISING THE CONCERN WHETHER THEY WILL COME THROUGH BROKEN OR SCATTERED. FOR NOW...WILL CONTINUE TO SHOW A BROKEN DECK COMING THROUGH LATE TONIGHT INTO WEDNESDAY MORNING. IF THIS HAPPENS...IT SHOULD PRECLUDE ANY FOG FROM FORMING AT KLSE AS WELL. TEMP/DEW POINT SPREAD WAS AT 9 DEGREES AT 03Z WHICH IS A LITTLE OUTSIDE THE OPTIMAL RANGE WANTED FOR FOG FORMATION. WILL MAINTAIN THE VCFG IN CASE THE CLOUDS COME THROUGH SCATTERED INSTEAD OF BROKEN...BUT CONFIDENCE IS PRETTY LOW ON FOG FORMATION. AS THE HIGH PULLS OFF TO THE EAST WEDNESDAY AFTERNOON...COULD BE ENOUGH MOISTURE RETURN TO GENERATE SOME AFTERNOON CUMULUS AT KRST BUT NOT EXPECTING THERE TO BE ANY SHOWER DEVELOPMENT. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...WETENKAMP LONG TERM...WETENKAMP AVIATION...04
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1112 PM MDT TUE JUL 23 2013 .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 330 PM MDT TUE JUL 23 2013 AN INFLUX OF MONSOONAL MOISTURE WILL INDICATE A TURN TO A MUCH MORE CLIMATOLOGICALLY NORMAL PERIOD OF UNSETTLED WEATHER BEGINNING WEDNESDAY AND CONTINUING THROUGH MUCH OF THE LONGER TERM. BEFORE THEN...AFTERNOON SATELLITE PIX SHOW SHALLOW CONVECTION BEGINNING TO DEVELOP OVER THE NORTHERN LARAMIE RANGE. A RESULT OF LLVL CONVERGENCE DUE TO A STATIONARY BOUNDARY DRAPED UP ALONG THE FRONT RANGE. DEW POINTS WEST OF THIS BOUNDARY WERE BELOW 30F...WITH RAWLINS REPORTING 11F. MORE AMPLE LLVL MOISTURE EAST OF THIS BOUNDARY AS INDICATED BY 50 DEGREE DEW POINTS. IN FACT...THIS BOUNDARY PUSHED EAST OF KCYS EARLY THIS MORNING DROPPING DEWPOINTS BRIEFLY BACK INTO THE 20S. MOST OF THE CWA WILL REMAIN DRY THIS EVENING...THESE EXCEPTION BEING THE FAR EASTERN ROW OF COUNTIES FROM CHADRON TO BRIDGEPORT. AS HAS BEEN THE CASE THE PAST SEVERAL DAYS...12Z MODEL OUTPUT CONTINUES TO SUGGEST CAP WILL HOLD AND THE AREA WILL REMAIN DRY. EVEN THE LATEST HRRR DEVELOPS CONVECTION JUST EAST OF THE CWFA. PERSISTENCE SAYS OTHERWISE HOWEVER...SO WILL KEEP SLIGHT CHANCES GOING FROM CHADRON AND BRIDGEPORT. IF THE CAP DOES MANAGE TO BREAK...SBCAPES OF 1000 TO 1500 J/KG WOULD BE REALIZED WHICH COULD RESULT IN SOME SEVERE DEVELOPMENT. ANY THUNDERSTORMS WILL WIND DOWN BY LATE EVENING. ATTENTION THEN SHIFTS TO UPSTREAM MOISTURE AND SHORTWAVE EVIDENT ON WV IMAGERY FROM NRN CA/SRN OR EAST INTO UTAH. THIS SUB-TROPICAL MONSOON MOISTURE PLUME AND SHORTWAVE WILL SLOWLY MEANDER NORTH INTO THE REGION ON WEDNESDAY. 12Z MODELS HAVE DELAYED ITS ARRIVAL BY A FEW HOURS. ALTHOUGH THERE IS SOME POTENTIAL FOR DRY LIGHTNING EARLY WEDNESDAY...AM NOT CONFIDENT ON ITS COVERAGE. SO FOR NOW...HAVE MAINTAINED THE INHERITED COVERAGE...BUT HAVE CONFINED IT TO THE SNOWY/SIERRA MADRE RANGES WEDNESDAY MORNING. BY MIDDAY WEDNESDAY...CONVECTION WILL BE DEVELOPING OVER THE SE WYOMING MOUNTAINS AND ADJACENT FOOTHILLS/VALLEY LOCATIONS. PROGD SBCAPES WILL NOT BE PARTICULARLY HIGH (500-800 J/KG). HOWEVER PWATS RISING ABOVE AN INCH ALONG WITH STORM MOTIONS OF 10 KNOTS OR LESS WILL RESULT IN EFFICIENT RAIN PRODUCERS. CAN NOT RULE OUT THE POTENTIAL FOR SMALL HAIL TOO...THOUGH THERMODYNAMIC PARAMETERS ARE NOT FAVORABLE. SHORTWAVE WILL MEANDER ATOP THE CWA WEDNESDAY NIGHT WHICH SHOULD AID IN THE CONTINUATION OF NOCTURNAL CONVECTION. MID/UPPER-LEVEL FLOW WILL TURN NORTHWEST FOR THURSDAY BEHIND DEPARTING SHORTWAVE. AT THE SFC...A WEAK COOL FRONT ALONG WITH FAVORABLE UPSLOPE BEHIND FROPA WILL SET THE STAGE FOR ANOTHER ROUND OF AFTERNOON AND EVENING SHOWERS/THUNDERSTORMS. AGAIN AMPLE MOISTURE WILL ACT TO LIMIT SEVERE POTENTIAL...ONLY YIELDING SBCAPES OF 500-800 J/KG. STORM MOTIONS WILL AGAIN BE LESS THAN 10 KNOTS. THE THICKER CLOUD CANOPY ALONG WITH WEAK COLD FROPA ON THURSDAY WILL CAUSE TEMPERATURES TO COOL FROM THE UPPER 80S ON WEDNESDAY INTO THE LOWER 80S ON THURSDAY. .LONG TERM...(THURSDAY NIGHT THROUGH MONDAY) ISSUED AT 330 PM MDT TUE JUL 23 2013 MONSOONAL MOISTURE WILL CONTINUE TO STREAM INTO THE REGION ON FRIDAY THROUGH THE WEEKEND. SHORTWAVE MOVES SOUTHWARD ACROSS THE NORTHERN HIGH PLAINS ON THURSDAY NIGHT WITH RISING SFC PRESSURES BEHIND IT OVER THE PLAINS. THIS RESULTS IN GOOD SOUTHEAST UPSLOPE BY FRIDAY WITH PW VALUES OF 1.00-1.25 INCHES OVER MOST AREAS ALONG AND EAST OF THE LARAMIE RANGE. WIDESPREAD QPF IS DEPICTED ON BOTH THE GFS AND ECMWF BY FRIDAY AFTN/EVENING. WITH DEEP LAYER SHEAR OF 50 KTS AND CAPE VALUES OF 1250-1500 J/KG...A FEW STRONG TO SEVERE STORMS COULD BE POSSIBLE OVER THE PLAINS. THE STEERING FLOW IS A LITTLE TOO FAST FOR MAJOR FLASH FLOODING CONCERNS ON FRIDAY. UPPER LEVEL RIDGE AXIS IS POSITIONED OVER WESTERN WY BY SATURDAY AFTN...WITH NORTHWESTERLY MIDLEVEL FLOW PERSISTING IN THE CWA. CONVECTIVE PARAMETERS APPEAR VERY SIMILAR TO FRIDAY...SO GENERALLY CARRIED THE SAME POPS. RIDGE AXIS IS ALMOST DIRECTLY OVER THE CWA BY SUNDAY WITH STEERING FLOW BECOMING MORE WESTERLY AND SOMEWHAT SLOWER THAN THE PREVIOUS DAYS. SHORTWAVE ROTATES THROUGH THE AREA DURING PEAK HEATING AND WITH PW VALUES REMAINING ABOVE NORMAL...EXPECT ANOTHER DAY OF GOOD STORM COVERAGE. DRIER 700-500MB FLOW CREEPS INTO THE REGION BY MONDAY WHICH COULD RESULT IN MORE ISOLATED TSTM CHANCES. TEMPS THROUGHOUT THE PERIOD WILL BE SLIGHTLY BELOW AVERAGE WITH THE MOIST AIRMASS AND RATHER CLOUDY CONDITIONS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY EVENING) ISSUED AT 1112 PM MDT TUE JUL 23 2013 VFR EXPECTED ACROSS ALL AERODROMES FOR THE REST OF THE NIGHT THROUGH EARLY WEDS AFTERNOON. INCREASING MONSOONAL MOISTURE SHOULD ALLOW FOR SOMEWHAT MORE WIDESPREAD SHOWERS AND STORMS WEDS AFTERNOON AND EVENING WITH ASSOCIATED PERIODS OF LOWERED VSBYS AND GUSTY WINDS IN THE STRONGER STORMS. && .FIRE WEATHER... ISSUED AT 330 PM MDT TUE JUL 23 2013 MONSOONAL MOISTURE WILL RETURN TO THE DISTRICT IN EARNEST DURING THE DAY ON WEDNESDAY. AS THIS OCCURS...WE MAY BE ABLE TO SEE SOME HIGH-BASED SHOWER/THUNDERSTORM DEVELOPMENT MAINLY OVER THE SNOWY AND SIERRA MADRE RANGES. AM NOT CONFIDENT OF WHETHER OR NOT THIS WILL OCCUR...BUT IF IT DOES THE BEST TIME WILL BE BETWEEN 6AM AND NOON WEDNESDAY. AFTER THAT...BETTER CHANCES FOR SHOWERS AND THUNDERSTORMS WILL RETURN TO THE DISTRICT BEGINNING WEDNESDAY AFTERNOON AND CONTINUING INTO THE UPCOMING WEEKEND. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...NONE. NE...NONE. && $$ SHORT TERM...HAHN LONG TERM...FINCH AVIATION...LIEBL FIRE WEATHER...HAHN
AREA FORECAST DISCUSSION...UPDATE
NWS PEACHTREE CITY GA
720 AM EDT WED JUL 24 2013 .SHORT TERM /TODAY THROUGH THURSDAY/... /ISSUED AT 349 AM EDT WED JUL 24 2013/ A VERY ACTIVE WEATHER PATTERN WILL PERSIST TODAY WITH CURRENT SATELLITE WATER VAPOR IMAGERY SHOWING A SHARP UPPER SHORT WAVE OVER SE GA AND DEPARTING EASTWARD... AND A SERIES OF MORE SUBTLE DISTURBANCES EMBEDDED WITHIN THE NW FLOW ALOFT BACK TO THE WEST AND NW. REGIONAL RADAR SHOWS ISOLATED STORMS ACROSS WESTERN AL... AND THIS ACTIVITY IS ASSOCIATED WITH A WEAK DISTURBANCE PUSHING ACROSS WEST TN AND NORTH MS. FURTHER WEST... SATELLITE AND RADAR SHOW A LARGE CONVECTIVE COMPLEX ACROSS WESTERN OK/AR... AND DROPPING SSE ON A TRAJECTORY FOR THE SE TX AND LA COASTS. SURFACE ANALYSIS SHOWS A WEAK FRONTAL BOUNDARY PUSHING INTO NW TN AND EXTENDING NEWD INTO VA. SHORT RANGE MODELS SHOW THESE SUBTLE DISTURBANCES TO THE WEST INTERACTING WITH A MOIST /1.8+ PW/ AND MODERATELY UNSTABLE /2000-2500 CAPE/ AIR MASS OVER GA TO PRODUCE SCATTERED SHOWERS AND THUNDERSTORMS AGAIN TODAY... MAINLY DURING THE AFTERNOON AND EVENING HOURS. THE GREATER CHANCES APPEAR TO BE ACROSS NORTH GA AHEAD OF THIS SAGGING COLD FRONT... AND AGAIN ACROSS THE WESTERN ZONES WHERE THE LOCAL WRF MODEL SHOWS ANOTHER CONVECTIVE COMPLEX DIVING SOUTHWARD ACROSS AL AND BRUSHING THE WESTERN COUNTIES DURING THE AFTERNOON. THE HRRR MODEL SHOWS MORE CONVECTION CONCENTRATED ALONG AND AHEAD OF THE APPROACHING COLD FRONT THAT PUSHES INTO NORTH GA BY EARLY-MID AFTERNOON. EXPECT THIS ACTIVITY TO PUSH SOUTH INTO CENTRAL GA DURING THE LATE AFTERNOON AND EVENING HOURS. THEREFORE... IT APPEARS STORMS COULD DEVELOP JUST ABOUT ANYWHERE TODAY. THE SLIGHTLY COOLER AND DRIER AIR ALOFT ASSOCIATED WITH THE NW FLOW CONTINUES TO SUGGEST A THREAT OF STRONG DOWNBURST WINDS AND LARGE HAIL THIS AFTERNOON AND EVENING DURING PEAK HEATING. THIS IS ALSO SUPPORTED BY SPC...WHO HAS BLANKETED A FIVE PERCENT CHANCE OF WIND AND HAIL THREAT ACROSS THE ENTIRE FORECAST AREA TODAY. ALL WARRANTS MENTION OF ISOLATED SEVERE STORMS... WITH LOCALLY HEAVY RAIN... DAMAGING WINDS AND LARGE HAIL IN THE HAZARDOUS WEATHER OUTLOOK FOR TODAY. MODELS SHOW STORM COVERAGE GREATLY DIMINISHING BEFORE MIDNIGHT WITH LOSS OF DAYTIME HEATING. SHORT RANGE MODELS AGREE ON SAGGING THE FRONT ACROSS NORTH GA OVERNIGHT WITH SOME DRIER AIR SPREADING DOWN INTO THE ATLANTA AREA EARLY ON THURSDAY. THIS SHOULD HOLD CONVECTION DOWN TO ISOLATED OR LESS FOR MUCH OF NORTH GA TO INCLUDE THE ATLANTA METRO AREA ON THURSDAY. EXPECT MORE SCATTERED CONVECTION ACROSS THE FAR NE AND CENTRAL ZONES WHERE MODELS SHOW CONVECTION FIRING ALONG AND OUT AHEAD OF THE NEARLY STATIONARY FRONT. COULD SEE A FEW STRONG TO SEVERE STORMS ACROSS THE FAR SOUTH AND SE ZONES THURSDAY AFTERNOON WHERE THE FRONT AND GREATER INSTABILITIES ARE EXPECTED. AS FOR TEMPS... LEANED TOWARD A BLEND BETWEEN PERSISTENCE AND THE SLIGHTLY WARMER MAV THROUGH THE SHORT TERM. 39 .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... /ISSUED AT 349 AM EDT WED JUL 24 2013/ NO REAL CHANGES TO THE PREVIOUS MODEL TRENDS THROUGH THE EXTENDED FORECAST PERIOD. FAIRLY GOOD AGREEMENT AMONG THE MEDIUM RANGE MODELS THROUGH THE WEEKEND AS FAR AS THE LARGER SCALE FEATURES ARE CONCERNED WITH A PERSISTENT EASTERN U.S. UPPER TROUGH DOMINATING THE REGIONAL WEATHER. EXTENDED FORECAST PERIOD STARTS OUT IN A BIT OF A QUIET PERIOD AS THE MAIN UPPER TROUGH AXIS IS EAST OF THE STATE... WITH SCATTERED...MAINLY DIURNAL...CONVECTION EXPECTED THROUGH FRIDAY. WEAK NORTHWESTERLY UPPER FLOW WILL KEEP A CHANCE FOR A ROUND OR TWO OF MORE ORGANIZED CONVECTION ASSOCIATED WITH ANY WEAK RIPPLES RIDING DOWN THE BACKSIDE OF THE TROUGH...BUT NO DISTINCT SHORT WAVE IS EVIDENT IN THE MODELS AT THIS TIME. FOR THE WEEKEND...A NEW SHORT WAVE DIGS INTO THE MID-SOUTH FRIDAY NIGHT AND SWEEPS ACROSS THE REGION SATURDAY. GFS/ECMWF/CMC/NAM ARE SURPRISINGLY SIMILAR WITH THIS FEATURE SO I WILL BE BUMPING UP SATURDAY/S POPS INTO THE LIKELY RANGE. FOR NOW THE MODELS ARE ONLY SHOWING A WEAK SURFACE BOUNDARY ASSOCIATED WITH THIS FEATURE. ALTHOUGH INSTABILITY IS FORECAST TO REMAIN MODERATE AT BEST SATURDAY...SOME WEAK SHEAR IS EVIDENT SO CONVECTION MAY BE A BIT MORE ORGANIZED AND AT LEAST A SMALL INCREASE IN THE POTENTIAL FOR SEVERE STORMS WILL NEED TO BE WATCHED WITH THIS SYSTEM. WEAK SURFACE TROUGHING AND WEAK UPPER LEVEL FLOW SETTLE IN FOR THE REMAINDER OF THE EXTENDED FORECAST PERIOD. MODELS ARE SHOWING A SIGNIFICANT REDUCTION IN DEEPER LAYER MOISTURE THURSDAY NIGHT AND FRIDAY...BUT AMPLE LOW-LEVEL MOISTURE REMAINS AVAILABLE FROM THE MOIST SURFACE CONDITIONS FOR SCATTERED CONVECTION. BETTER DEEP MOISTURE ACCOMPANIES THE SYSTEM SATURDAY. A FAIRLY STRONG MOISTURE GRADIENT SETS UP FOR THE BALANCE OF THE PERIOD INTO THE MIDDLE OF NEXT WEEK WITH RELATIVELY DRY AIR ACROSS THE NORTH. HOWEVER...IN THE ABSENCE OF A STRONG UPPER RIDGE THERE SHOULD BE SUFFICIENT MOISTURE AVAILABLE FOR ISOLATED TO SCATTERED...MAINLY DIURNAL...CONVECTION AREA-WIDE EACH DAY WITH AT LEAST SLIGHTLY BETTER CHANCES ACROSS CENTRAL GEORGIA. EXCEPT FOR SATURDAY WITH THE INCREASED CLOUD COVER AND PRECIPITATION EXPECTED...TEMPERATURES ARE EXPECTED TO REMAIN AROUND SEASONAL NORMALS THROUGH THE EXTENDED FORECAST PERIOD. 20 && .AVIATION... 12Z UPDATE... WIDESPREAD IFR AND MVFR CIGS THIS MORNING WILL GRADUALLY IMPROVE TO VFR LEVELS BY 15-16Z THIS MORNING. AN ACTIVE NW FLOW ALOFT WILL RESULT IN ANOTHER ROUND OF SCATTERED CONVECTION THIS AFTERNOON AND EVENING...MAINLY BETWEEN 18-24Z. WILL SHOW TEMPO TSRA 20-24Z AT ALL AIRPORTS TODAY. EXPECT WNW WINDS AROUND 10-12KTS WITH OCCASIONAL HIGHER GUSTS TODAY. MODELS SHOW A COLD FRONT SAGGING SOUTH OF ATL BY 09Z THU... SO EXPECT VFR CONDITIONS OVERNIGHT. THE DRIER AIRMASS BEHIND THE FRONT WILL KEEP ANY CONVECTION AROUND ATL ISOLATED AT BEST ON THU. //ATL CONFIDENCE...12Z UPDATE... MEDIUM ON AFTERNOON CONVECTION AROUND AIRPORTS. HIGH ON ALL ELEMENTS. 39 && .PRELIMINARY POINT TEMPS/POPS... ATHENS 89 70 89 69 / 30 30 40 20 ATLANTA 87 71 88 71 / 40 30 20 10 BLAIRSVILLE 84 65 81 62 / 40 30 30 20 CARTERSVILLE 88 67 88 66 / 50 30 20 10 COLUMBUS 90 72 92 71 / 40 30 40 10 GAINESVILLE 87 70 87 68 / 40 30 30 20 MACON 91 71 92 71 / 40 30 40 20 ROME 88 68 89 66 / 50 30 20 10 PEACHTREE CITY 87 67 89 67 / 40 30 20 10 VIDALIA 91 73 92 72 / 30 30 50 20 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...39 LONG TERM....20 AVIATION...39
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1006 AM CDT WED JUL 24 2013 .UPDATE... ISSUED AT 1001 AM CDT WED JUL 24 2013 SATELLITE HAS A RESPECTABLE SHORTWAVE DROPPING SOUTHEAST INTO IOWA. THE SLIGHTLY BETTER LIFT IS ACROSS MINNESOTA WERE SOME SHOWERS WERE OCCURRING AROUND KSTC. THIS PRECIPITATION AND THE SPRINKLES AT KDEH ARE IN AN AREA OF CONVERGENCE AND ISENTROPIC LIFT. THE RAP TRENDS INDICATE THIS ISENTROPIC LIFT WILL TURN MORE INTO DOWN GLIDE AS THE LATE MORNING AND AFTERNOON PROGRESS ACROSS THE AREA. THUS THE CLOUDS ASSOCIATED WITH THE SHORTWAVE SHOULD THIN WITH TIME. HOWEVER...THE VERY WEAK CONVERGENCE WILL PERSIST THROUGH MID AFTERNOON SO ONE CANNOT RULE OUT ISOLATED POCKETS OF SPRINKLES. THERE SHOULD BE A FAIR AMOUNT OF VIRGA ASSOCIATED WITH THE CLOUDS. ..08.. && .SYNOPSIS... ISSUED AT 338 AM CDT WED JUL 24 2013 CANADIAN HIGH PRESSURE OVER ND AND NORTHERN MN WAS THE DOMINANT SURFACE FEATURE OVER THE REGION EARLY THIS MORNING. RESULTING DRY AIR AND SUBSIDENCE WAS RESULTING IN MOSTLY CLEAR SKIES ACROSS THE NORTHERN HALF OF THE FORECAST AREA. ACROSS THE SOUTH...SATELLITE IMAGERY REVEALED A DECK OF AC EXPANDING ACROSS SE IA INTO W CENTRAL IL AND A SHIELD OF CI...ASSOCIATED WITH A VERY LARGE MCS OVER OK AND AR...REACHING INTO FAR NORTHEAST MO. LIGHT NE WINDS WERE ADVECTING DEWPOINTS IN THE 50S INTO THE AREA...WHILE TEMPERATURES WERE COOLING TOWARD ANTICIPATED LOWS IN THE LOWER 50S NORTHEAST TO NEAR 60 IN THE FAR SOUTH. ALOFT...A NW FLOW BETWEEN A CENTRAL ROCKIES RIDGE AND TROUGH OVER THE EASTERN U.S. REMAINED IN PLACE. THE NEXT UPSTREAM SHORTWAVE WAS MOVING ACROSS SOUTH DAKOTA...ON A TRACK TO MOVE THROUGH THE FORECAST AREA TODAY. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 338 AM CDT WED JUL 24 2013 THE MAIN FOCUS IS ON CONTINUED BELOW NORMAL TEMPERATURES AS HIGH PRESSURE KEEPS A COOL...DRY AIRMASS IN PLACE. THE HIGH PRESSURE RIDGE IS EXPECTED TO PASS TO THE NORTHEAST TO EXTEND FROM LOWER MI SW INTO MO BY THURSDAY MORNING. WHILE THIS WILL PROVIDE LOW LEVEL SUBSIDENCE AND A FEED OF DRY AIR ON LIGHT EAST TO NORTHEAST WINDS. AN ACTIVE UPPER LEVEL NW FLOW AND THE EMBEDDED SHORTWAVE AND AXIS OF MID LEVEL MOISTURE MOVING OUT OF THE NORTHERN PLAINS WILL LIKELY RESULT IN PASSING MID LEVEL CLOUDS THAT COULD BE RATHER EXTENSIVE AROUND LATE MORNING THROUGH EARLY AFTERNOON OVER ESPECIALLY THE NORTH. THE LIMITED INSOLATION DURING PEAK HEATING...ALONG WITH A MORE EASTERLY SURFACE WIND COMPONENT AND COOLER MORNING START SUPPORTS SLIGHTLY COOLER HIGHS THAN YESTERDAY AND HAVE STAYED WITH A RANGE FROM THE LOWER 70S NORTH TO UPPER 70S SOUTH. MODEST MID LEVEL LIFT MAY AGAIN LEAD TO HIGH BASED SHOWERS OVER THE ESPECIALLY THE NORTH IN THE AFTERNOON...BUT MUCH LIKE YESTERDAY...WILL KEEP A DRY FORECAST ANTICIPATING LITTLE MORE THAN VIRGA. TONIGHT...MID LEVEL SUBSIDENCE IS SHOWN OVERSPREADING THE REGION...WHICH ALONG WITH THE PASSING SURFACE RIDGE AXIS SHOULD PROVIDE MOSTLY CLEAR SKIES AND LIGHT WINDS. MIN TEMPERATURES FROM THE PREVIOUS FORECAST IN MID TO UPPER 50S LOOK ON TRACK AND ONLY MINOR TWEAKS WERE MADE. THESE VALUES WOULD BE ROUGHLY A CATEGORY ABOVE RECORD LOWS FOR THE 25TH...WHICH ARE INCLUDED IN THE CLIMATE SECTION BELOW FOR REFERENCE. CANNOT RULE OUT GROUND FOG AS WINDS WILL BE LIGHT TO NEARLY CALM TOWARD SUNRISE...BUT DO NOT EXPECT ENOUGH COVERAGE OR IMPACTS TO WARRANT MENTION IN THE FORECAST. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 338 AM CDT WED JUL 24 2013 FOCUS IN THE EXTENDED IS ON TIMING AND AMOUNTS OF PCPN CHANCES FOR THURSDAY NIGHT THROUGH FRIDAY NIGHT. TWO SEPARATE AREAS OF LOW PRESSURE...ONE MOVING ACROSS THE UPPER MS RIVER VALLEY AND THE OTHER IN THE SOUTHERN PLAINS...WILL INTERACT WITH ONE ANOTHER AS THE NORTHERN LOW SWEEPS A COLD FRONT THROUGH THE AREA ON FRIDAY. THE SOUTHERN SYSTEM MAY STEAL SOME ENERGY/MOISTURE AS MODELS SHOW IT TO MOVE ESE ACROSS CENTRAL/SOUTHERN MO. DO BELIEVE MOST AREAS/NW TWO THIRDS/ WILL SEE A GOOD CHANCE /50POP/ OF RAIN BUT AM NOW THINKING THAT THE ENERGY/PCPN MAY BE SHEARING OUT AS THE FRONT MOVES INTO THE SE THIRD OF THE CWFA AND THE SOUTHERN LOW FOCUS/S HEAVIER RAINS ACROSS MO. THUS LEFT LOWER 35-40 POPS AND PCPN AMOUNTS IN SE. STEPPED OUT PCPN CHANCES FRIDAY EVENING...WITH LINGERING SLIGHT CHANCES IN SE AFTER MIDNIGHT. THIS MAY BE TOO SLOW AND ALL PCPN MAY BE DONE BY LATE EVENING. ALL IN ALL...RAINFALL TOTALS LOOK TO RANGE FROM AROUND A THIRD OF AN INCH IN THE NW...TO A TENTH OF AN INCH SE. SEASONABLY COOL AND DRY CONDITIONS WILL BE FOUND ACROSS THE AREA FOR THE WEEKEND. TEMPERATURES WILL BE IN THE UPPER 70S/LOWER 80S ON THURSDAY...WITH MID 70S TO LOWER 80S ON FRIDAY AS SHOWERS AND STORMS MOVE THROUGH. MILD LOWS THURSDAY NIGHT /L-M 60S/ AS MOISTURE BUILDS AHEAD OF FRONT. BEHIND THE FRONT MUCH COOLER AIR IS FOUND. SATURDAY MORNING LOWS WILL SLIP INTO LOWER 50S NW TO NEAR 60 SE...WITH HIGHS SATURDAY AFTERNOON STRUGGLING TO REACH 70 NORTH TO THE UPPER 70S SOUTH. SUNDAY AM LOWS LOOKS TO BE COLDEST...WITH READINGS GENERALLY 53-58 DEGREES. A GRADUAL WARM UP BEGINS SUN THROUGH TUE WITH HIGHS IN THE MID 70S TO LOWER 80. THE NEXT CHANCE FOR RAIN COMES IN MONDAY THROUGH TUESDAY. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 605 AM CDT WED JUL 24 2013 HIGH PRESSURE WILL PROVIDE DRY WEATHER WITH LIGHT EAST TO SOUTHEAST WINDS TODAY AND TONIGHT. A WEAK UPPER LEVEL DISTURBANCE WILL SEND MID AND HIGH LEVEL CLOUDS ACROSS THE AREA FROM MID MORNING THROUGH EARLY AFTERNOON. SOME GROUND FOG WILL BE POSSIBLE TOWARD SUNRISE THURSDAY MORNING. FOR NOW...THIS IS HANDLED WITH TEMPO GROUPS AND MVFR VISIBILITIES. && .CLIMATE... ISSUED AT 338 AM CDT WED JUL 24 2013 RECORD LOWS FOR JULY 25... MOLINE.........52 IN 1933 CEDAR RAPIDS...50 IN 2004 DUBUQUE........50 IN 2004 BURLINGTON.....53 IN 1911 && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ UPDATE...08 SYNOPSIS...SHEETS SHORT TERM...SHEETS LONG TERM...14 AVIATION...SHEETS CLIMATE...SHEETS
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
727 AM EDT WED JUL 24 2013 .SYNOPSIS... QUIET AND COMFORTABLE WEATHER CAN BE EXPECTED FOR THE REMAINDER OF THE WORK WEEK AS HIGH PRESSURE SETTLES OVER THE REGION. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... POST DAWN UPDATE FEATURED ADJUSTMENTS TO HOURLY TRENDS OF CLOUDS AND TEMPS ONLY. PREVIOUS... TOUGHEST PART OF FORECAST TODAY...TRYING TO DETERMINE HOW FAST STRATO-CU DECK WILL DISSIPATE. THERE ARE LARGE HOLES THAT HAVE DEVELOPED IN THE LOW CLOUD DECK AND NONE OF THE MODELS ARE DOING A VERY GOOD JOB OF PICKING UP ON THIS. LATEST NAM AND HRRR ARE SIMILAR IN HOLDING ON TO THE CLOUD DECK AT LEAST THROUGH THE MORNING...DECAYING FROM THE NORTH AS THE DRIER AIR MOVES IN. HAVE SOME RESERVATIONS ON THIS...AS STATED PREVIOUSLY...MODELS ARE NOT DEPICTING CURRENT CONDITIONS WELL. WILL GO WITH A GRADUAL DECREASE IN CLOUD COVER FROM NORTH TO SOUTH THIS MORNING. DRIER AND COOLER AIR WILL ACCOMPANY A LARGE SURFACE HIGH...WHICH WILL MOVE THROUGH THE WESTERN GREAT LAKES TODAY. THE FLOW ALOFT WILL BECOME CYCLONIC AS A SHORTWAVE TROUGH MOVES TOWARD THE AREA LATE THIS AFTERNOON. WILL LEAN CLOSE TO CURRENT LAMP NUMBERS FOR HIGHS WHICH SHOULD BE WELL BELOW NORMAL. OVERALL CONDITIONS WILL BE VERY COMFORTABLE AS SFC TDS FALL IN THE LOWER TO MID 50S. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/... UPPER LEVEL TROUGH WILL HANG AROUND THROUGH MUCH OF THURSDAY NIGHT AS A DRY AIR MASS TAKES HOLD. EXPECT PLENTY OF SUNSHINE THURSDAY WITH BELOW NORMAL TEMPS. RIDGE WILL BUILD IN FRIDAY KEEPING THE AREA DRY AND WARMING TEMPS TO NEAR NORMAL LEVELS. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... A LONG WAVE TROUGH IS FORECAST TO CONTROL ERN CONUS WEATHER THROUGH THE WEEKEND. AS A RESULT...AOB SEASONAL AVERAGE TEMPS CAN BE EXPECTED AS WELL AS SHRTWV DEPENDENT PCPN CHCS. BEYOND THE WEEKEND...MDL CONSENSUS IS THAT THE TROF WL BGN TO FILL...HENCE THE NEW WEEK WL FEATURE WARMER TEMPS AND LOWER POPS. && .AVIATION /11Z WEDNESDAY THROUGH SUNDAY/... STRATOCU IN THE COLD ADVCTN REGIME BEHIND LAST NGTS CDFNT WL CONT TO FLOW OVR UPR OHIO PORTS THIS MRNG...BUT CLD DECKS ARE EXPECTED TO RMN JUST ABOVE THE MVFR AT MOST PORTS...AND THOSE RESTRICTIONS WL BE BRIEF. SFC TROF TO THE N OF I 80 HAS BACKED WIND TO THE NW AT FKL AND DUJ...BUT THAT FEATURE WL NOT LINGER AND A MODEST N WIND WL FLOW ACRS AREA TERMINALS TDA. OUTOUTLOOK.../THURSDAY THROUGH SUNDAY/... THE NXT CHC FOR GENL RESTRNS IS EXPECTED WITH THE APPRCH AND PASSAGE OF A WEEKEND CDFNT. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$ 15
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
547 AM CDT WED JUL 24 2013 .UPDATE... 12Z AVIATION DISCUSSION ADDED BELOW. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 259 AM CDT WED JUL 24 2013 SPRAWLING COOL AND DRY CANADIAN HIGH IN PLACE AT THE SFC TO START OFF THE DAY. UPSTAIRS THOUGH...A WAVY NW FLOW HAS KEPT A STEADY DIET OF MID CLOUDS STREAMING ACROSS THE AREA OVERNIGHT...WHICH HAS KEPT TEMPS FROM FALLING OFF AS MUCH THEY COULD...ESPECIALLY OVER MN. FOR THE REST OF THE SHORT TERM...WE WILL SEE HEIGHTS BUILD SOME TODAY OUT AHEAD OF A STRONG SHORTWAVE MOVING THROUGH THE CANADIAN PRAIRIES TOWARD NRN MN BY THE END OF THE PERIOD. AT THE SFC...THE HIGH WILL SLIP INTO THE GREAT LAKES WHILE A COLD FRONT SLIPS ACROSS NODAK AND INTO NW MN BY THURSDAY MORNING. BIG QUESTION FOR TODAY WAS TO OR NOT TO INCLUDE SOME ISO THUNDER IN THE FORECAST. IF YOU HEAD OFF IN SEARCH OF YOUR FAVORITE CAM...YOU LIKELY HAVE SEEN THAT MOST GENERATE SOME ISOLATED CONVECTION BY THE AFTERNOON SOMEWHERE NEAR THE I-35 CORRIDOR...BUT AFTER TAKING A PEAK AT SOME DETERMINISTIC GUIDANCE TO SUPPORT THE ISO STORMS...DECIDED AGAINST INCLUDING ANYTHING THROUGH THE AFTERNOON IN THE GRIDS. THERE WERE TWO THINGS THAT PUSHED ME TOWARD A DRY FORECAST FOR TODAY. FIRST...THE RAP CONTINUES TO SHOW NO MUCAPE ACROSS THE MPX AREA THIS AFTERNOON...WITH BEST LI/S REMAINING ABOVE ZERO...NOT EXACTLY WHAT YOU WANT TO SEE FOR THUNDERSTORMS. SECOND...EVEN THOUGH THE NAM GENERATES 500-1000 J/KG OF MLCAPE BY THE AFTERNOON...A QUICK LOOK AT SOUNDINGS ACROSS THE AREA SHOWS THAT IT IS A VERY SKINNY CAPE PROFILE AND ONE THAT DOES NOT LOOK PROMISING FOR GENERATING DEEP MOIST CONVECTION. SO AFTER MUCH DEBATE...DECIDED TO JOIN THE GEM AND ECMWF IN GOING DRY FOR TODAY. THIS EVENING/TONIGHT...PRECIP CHANCES DO LOOK AT LEAST MARGINALLY BETTER. THE REASON IS THAT AS THE STRONG SHORTWAVE DROPS SOUTH OUT OF CANADA...WE WILL SEE H85 WINDS...MOISTURE TRANSPORT AND WAA SLOWLY INCREASING DURING THE NIGHT. THOUGH NOT IMPRESSIVE BY ANY MEANS...USUALLY A PRETTY RISKY PROPOSITION TO NOT INCLUDE SOME POPS FOR A NIGHT TIME PERIOD IN THE SUMMER THAT FEATURES AT LEAST WEAK WAA AND MOISTURE TRANSPORT AT THE H85 LEVEL. MOST LIKELY SCENARIO AT THE MOMENT LOOKS TO BE REMNANTS OF CONVECTION THAT DEVELOPS IN NRN MN THIS AFTERNOON DROPPING SE INTO EC MN AND WRN WI OVERNIGHT. FOR NOW HAVE CHANCE POPS ROUGHLY ALONG AND NORTH OF I-94...THOUGH DO NOT HAVE MUCH CONFIDENCE IN HOW STORMS TONIGHT WILL PLAY OUT AT THE MOMENT. FOR TEMPERATURES...925-850 TEMPS INCREASE TO BETWEEN 16C AND 20C OUT IN WRN MN THIS AFTERNOON...WHICH WILL SUPPORT TEMPERATURES WARMING INTO THE LOW-MID 80S IF CLOUD COVER DOES NOT SLOW THINGS DOWN TOO MUCH. AS A RESULT...DID NUDGE HIGHS UP A COUPLE OF DEGREES OUT WEST...BUT WILL HAVE TO SEE HOW CLOUDS PLAY OUT. TONIGHT...WEAK SRLY FLOW AND WAA SHOULD KEEP TEMPS SIMILAR TO WHAT WE ARE SEEING UNDER THE CLOUDS IN MN TONIGHT...AND ABOUT 5 DEGS WARMER THAN WHAT WE ARE SEEING OVER IN WI RIGHT NOW. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 259 AM CDT WED JUL 24 2013 MAIN ISSUE IN THE LONG TERM IS THUNDERSTORMS AND POTENTIAL FOR SEVERE WX THU AFTN AND EVE...THEN THE MUCH COOLER TEMPERATURES EXPECTED FOR THE WEEKEND. AN UPPER LEVEL LOW CENTER WILL DROP OUT OF MANITOBA THU MRNG SWWD ON ITS WAY INTO THE GRT LAKES. AT THE SFC...A POTENT CDFNT WILL BE LINKED BY TWO ANCHOR LOW PRES CENTERS...ONCE JUST N OF KINL AND THE OTHER OVER SW SD BY MIDDAY WED. THESE TWO SFC LOW PRES CENTERS WILL PHASE TOGETHER OVER THE GRT LAKES BY MIDDAY FRI...SHOVING THE CDFNT THRU THE REGION FRI MRNG WHILE THE UPPER LEVEL LOW DEEPENS INTO A POTENT COMPACT LONGWAVE TROUGH OVER THE UPPER MISSISSIPPI RIVER VALLEY. EFFICIENT WARM SECTORING AHEAD OF THE CDFNT WILL DRAG WARM AND MORE MOIST AIR FROM THE DEEP S UP INTO THE REGION FOR MID-TO-LATE THU. STRONG JETTING IN THE MID- AND UPPER-LEVELS WILL ENHANCE TSTM DEVELOPMENT DURG THE DAY ON THU. OF NOTE HOWEVER IS COLD AIR ALOFT...A FUNCTION OF THE UPPER LOW DROPPING S. THIS WILL ALLOW GROWING STORMS TO HIT THE FREEZING LEVEL QUICKLY... WORKING WITH STEEP LAPSE RATES TO MAKE LARGE HAIL A SEVERE WX HAZARD. IN ADDITION...HELICITIES INCRS SIGNIFICANTLY INVOF THE FNT WITH SWLY WINDS AT THE SFC AND NW FLOW ALOFT DUE TO LOCATION OF THE UPPER LOW. ISOLD TORNADOES...PARTICULARLY OVER SRN MN...ARE ANOTHER POTENTIAL SEVERE WX HAZARD. THE SPC HAS ADDED A SLGT RISK FOR SRN-ERN MN INTO WRN WI IN THE MORNING SWODY2 AND THIS IS WELL WARRANTED. THE CDFNT WILL SHIFT WELL INTO THE GRT LAKES BY FRI EVE...ALLOWING DEEP N-NW FLOW CAA TO COMMENCE. THE UPPER LOW WILL THE SIT-AND- SPIN OVER THE GRT LAKES THRU SUN...KEEPING TEMPERATURES 10-12 DEGREES BELOW NORMAL FRO THRU THE WEEKEND. H85 TEMPS DROP TO ABOUT 6-8 DEG C...WHICH WILL TRANSLATE TO LOWS ARND 50 AND HIGHS ARND 70 FRI THRU SUN. THE DENSE SFC HIGH PRES ASSOCIATED WITH THIS COOLDOWN WILL SHIFT TO THE E DURING THE EARLY PORTION OF NEXT WEEK...ALLOWING FOR A WARMER RETURN FLOW ON THE BACKSIDE OF THE HIGH. TEMPS WILL RISE BACK CLOSER TO NORMAL LEVELS WHILE SEVERAL SHORTWAVE DISTURBANCES RIDE WITHIN THE FLOW BETWEEN A RIDGE OVER THE PLAINS AND A TROUGH OVER THE APPALACHIANS. THESE DISTURBANCES MAY BE ABLE TO SQUEEZE ENOUGH LIMITED MOISTURE TO PRODUCE ISOLD TO SCATTERED SHOWERS AND TSTMS MON-TUE. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 529 AM CDT WED JUL 24 2013 SHORTWAVE MOVING ACROSS MN OUT THE GATE PRODUCING FAIRLY EXTENSIVE CLOUD COVER...WITH NOTHING MORE THAN A COUPLE OF SPRINKLES EXPECTED FROM IT. STRONGER WAVE BACK NEAR BISMARK WILL BE OVER MN BY 18Z...AND THIS APPEARS TO BE WHAT THE HRRR IS KEYING ON FOR SCT CONVECTION ALONG I-35 THIS AFTERNOON. COVERAGE LOOKS SPARSE...AND CONFIDENCE IN ANYTHING OCCURRING IS NOT ALL THAT GREAT GIVEN REASONING IN SHORT TERM DISCUSSION. LATE TONIGHT...THERE IS THE POTENTIAL FOR SCATTERED THUNDERSTORMS FROM CENTRAL MN SOUTHEAST INTO WESTERN WI. TIMING WOULD BE 6-9Z FOR ERN MN AND 9-12Z FOR WRN WI. AGAIN COVERAGE LOOKS SPARSE AND CONFIDENCE TOO LOW TO INCLUDE IN TAFS. WITH HIGH PRESSURE SLOWLY SLIDING TO MICH...WINDS WILL BE LIGHT TO DAY AND GRADUALLY TAKING ON MORE OF A WRN COMPONENT. KMSP...THERE WILL BE A SMALL THREAT FOR A SHRA/TSRA BETEWEEN 18Z AND 21Z...AND AGAIN FROM 6-9Z. CONFIDENCE AND EXPECTED COVERAGE THOUGH ARE TOO LOW TO INCLUDE IN TAF AT THIS POINT. WINDS THIS PERIOD LOOK TO REMAIN 7 KTS OR LESS...SO SHOULD ALLOW FOR SOME LEEWAY WITH RUNWAY SELECTION. /OUTLOOK FOR KMSP/ THU...AFTERNOON TSRA LIKELY. MVFR OR LOWER CONDS POSSIBLE IN TSRA. WINDS SW 5-10 KT. FRI...VFR. WINDS NW 10G20 KT. SAT...VFR. WINDS NW 5-10 KT. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...MPG LONG TERM...JPC AVIATION...MPG
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON MS
1100 AM CDT WED JUL 24 2013 .UPDATE... UPPER S/WV CONTINUE TO MOVE INTO THE REGION IN THE NW FLOW ALOFT AND THESE WILL ENHANCE THE POTENTIAL FOR SHOWERS/THUNDERSTORMS THIS AFTERNOON. AN MCV IS VERY EVIDENT IN VISIBLE SATELLITE/REGIONAL RADAR IMAGERY MOVING INTO E/SE MS. IN THE WAKE OF THE DEPARTING MCV...SUBSIDENCE HAS HELPED CLEAR SOME OF THE CLOUD COVER OVER THE REGION. DUE TO TO THIS...WENT CLOSE TO MAV NUMBERS BUT SEEMED TOO WARM IN THE W/NW AND DROPPED A FEW DEGREES. TEMPS WILL BE IN THE LOW 90S THIS AFTERNOON. DUE TO LESS CLOUD COVER FOR A FEW HOURS AND SOME HEATING...MAY BE ABLE TO GET SOME DECENT INSTABILITY THIS AFTERNOON. OVERALL REGIONAL SOUNDINGS INDICATE SOME DRY LOW LEVEL AIR AND MEAGER LAPSE RATES WITH VERTICAL TOTALS AROUND 25-26C. SOME STRONG STORMS ARE POSSIBLE THIS AFTERNOON. HI-RES MODELS INDICATE THAT CONVECTION WILL DEVELOP IN ANOTHER APPROACHING S/WV IN S/SE AR AND WILL MOVE SE...MAINLY AFTER 17Z. SOME STORM ACTIVITY COULD DEVELOP FROM THE PASSING FRONT JUST NORTH OF THE REGION IN CENTRAL/N TN. HRRR IS INDICATING MORE COVERAGE OF ACTIVITY FROM A LINE ALONG FROM GREENVILLE TO HATTIESBURG AND HI-RES WRF ALSO INDICATES A SIMILAR IDEA. WENT CLOSE TO MAV POPS BUT ADJUSTED SLIGHTLY. TEMPS/DEWPOINTS WERE ADJUSTED ACCORDING TO CURRENT TRENDS AND SKY COVER GRIDS WERE ADJUSTED SLIGHTLY. REST OF THE FORECAST IS ON TRACK. /DC/ && .AVIATION...MORNING IFR TO MVFR CEILINGS SLOWLY LIFTING TO VFR AND THIS WILL PREVAIL THROUGH THE AFTERNOON. ANOTHER ROUND OF SHRA/TSRA POSSIBLE TO IMPACT MOST AREAS AFTER 17Z TODAY. SFC WINDS WILL BE GENERALLY OUT OF THE WEST AND MAY OCCASIONALLY GUST THIS AFTERNOON ESPECIALLY WITH STORMS. TSRA SHOULD DIMINISH THIS EVENING WITH QUIET WEATHER EXPECTED OVERNIGHT. /28/ && .PREV DISCUSSION... /ISSUED 506 AM CDT WED JUL 24 2013/ UPDATE...DID A QUICK UPDATE TO INCLUDE MENTION OF SOME LIGHT RAIN ACROSS THE REGION THAT CONTINUES TO EXPAND TO THE NORTH/NORTHEAST OF THE MCV OVER NE LA. A TRANSITION TO MORE SHOWERY ACTIVITY EXPECTED LATER THIS MORNING. /BK/ PREV DISCUSSION... /ISSUED 431 AM CDT WED JUL 24 2013/ SHORT TERM...(TODAY THROUGH THURSDAY NIGHT)... COMPLICATED NORTHWEST FLOW REGIME PERSISTS OVER THE NEXT COUPLE DAYS...ALTHOUGH THINGS WILL SIMPLIFY A TAD HEADED INTO TOMORROW AS A COOL FRONT DRIFTS INTO THE AREA FROM THE NORTH. BUT BEFORE THEN WE NEED TO DEAL WITH A RATHER UNCERTAIN FORECAST FOR TODAY. A REMNANT MCV FROM A CONVECTIVE COMPLEX THAT DIED TO OUR WEST LAST NIGHT IS CURRENTLY DRIFTING ACROSS NORTHEAST LOUISIANA TOWARD SOUTHWEST MISSISSIPPI AT THIS HOUR...WITH A BROAD CIRRUS SHIELD TRYING TO OVERSPREAD THE REGION FROM THE NORTHWEST. THESE TWO ITEMS ARE GOING TO MAKE A CONVECTIVE FORECAST FOR TODAY RATHER DIFFICULT AS CONVERGENCE IN VICINITY OF THE MCV CALLS FOR INITIATION IN ITS VICINITY ONCE WE HEAT UP...WITH EXPANSIVE UPPER CLOUD COVER LIMITING THE HEATING POTENTIAL/AT LEAST FOR THE FIRST PART OF THE DAY. FURTHER NORTH...THE SYNOPTIC COOL FRONT LOOKS TO BE PASSING INTO FAR NORTHERN MS BY LATE MORNING WHICH SHOULD PROVIDE IMPETUS FOR SOME STORMS IN ITS VICINITY AS LONG AS WE GET SOME HEATING UP THERE/BUT THERE AGAIN THE EXPANSIVE CIRRUS SHIELD IS GOING TO MAKE THAT DIFFICULT FOR SEVERAL MORE HOURS. THE BROADER SCALE MODELS DO NOT SEEM TO HAVE A GOOD HANDLE ON WHAT IS GOING ON WHICH ISN`T SURPRISING...HOWEVER THE LATEST RUNS OF THE HRRR DO LOOK REASONABLE WITH THEIR EVOLUTION OF THINGS FOR TODAY AND HAVE LOOKED TO IT MORE THAN ANYTHING FOR SOME CLUES. I WOULD NOT BE SURPRISED TO SEE THE CIRRUS THIN HEADED INTO THE DAYBREAK HOURS ALLOWING SOME DECENT HEATING TO OCCUR THIS MORNING ACROSS A GOOD MAJORITY OF THE REGION. THIS IN CONJUNCTURE WITH THE REMNANT MCV AND SURFACE FRONT SHOULD ALLOW A COUPLE FOCUS AREAS FOR STORMS TO DEVELOP...ONE ACROSS THE I-20 CORRIDOR ON THE NORTHERN FRINGE OF THE MCV AND ANOTHER NORTH OF OUR CWA INVOF THE FRONT. FROM THERE I`D EXPECT A GENERAL EXPANSION TOWARD THE SOUTH/SOUTHEAST LIKE WE`VE SEEN ACROSS THE REGION THE LAST COUPLE DAYS. THIS WOULD LEAVE A MINIMUM IN ACTIVITY ACROSS THE DELTA TODAY...HOWEVER IF THE CIRRUS THINS UP THERE AS WELL AND WE GET SOME HEATING A CONDITIONAL RISK OF STORMS FIRING IN THAT VICINITY INVOF THE FRONT LOOKS POSSIBLE. AS FOR THE STRONG/SEVERE RISK TODAY...RELIED HEAVILY ON THE LATEST RUNS OF THE RUC AND ITS TEMPERATURE PROFILE TODAY WHICH LOOKS PRETTY MEAGER ON THE LAPSE RATE FRONT GIVEN ALL THE CONVECTIVE DEBRIS/CIRRUS AROUND. COINCIDENT WITH THE UNCERTAINTY IN WHERE THE BEST COVERAGE IN STORMS WILL BE TODAY AM GOING TO LEAVE THE HWO PRETTY GENERAL WITH ALL AREAS COVERED...AND WILL OMIT MENTION OF ANYTHING SEVERE UNTIL CONFIDENCE INCREASES IN STRONGER HEATING/INSTABILITY DEVELOPING. HEADED INTO TONIGHT...I WOULD NOT BE SURPRISED TO SEE THINGS QUIET DOWN AREA WIDE BY MID TO LATE EVENING AS A LOSS OF HEATING COUPLES WITH DRIER AIR ALOFT OVERSPREADING THE CWA. ISOLATED SHOWERS AND PERHAPS A FEW RUMBLES OF THUNDER LOOK PLAUSIBLE ALONG THE ADVANCING FRONT THROUGH THE NIGHT. BY THURSDAY MORNING THE FRONT LOOKS TO BE LOCATED ALONG/JUST SOUTH OF THE I-20 CORRIDOR. THIS SHOULD CONFINE ANY SHOWER AND STORM CHANCES TO SOUTHERN ZONES...AND AT THIS POINT IT DOESN`T APPEAR STRONG STORMS WILL BE A HUGE CONCERN. WE`LL BE TAKING A LOOK AT THAT AGAIN LATER TODAY/TONIGHT. TEMPS OFFERED BY THE GFS MOS LOOKED WARM TODAY CONSIDERING THE AFOREMENTIONED CLOUDS/CIRRUS AND STORM CHANCES FOR LATER ON. ONLY OTHER NOTABLE CHANGES WERE FOR FRI MORNING WHERE TEMPS WERE RAISED A TAD TOWARD WARMER NAM/ENSEMBLE NUMBERS. /BK/ LONG TERM...(FRIDAY THROUGH WEDNESDAY)... FOCUS OF THE LONG TERM WILL BE ON A WELL DEFINED DISTURBANCE FOR SATURDAY AND WHAT SORT OF PRECIP/IMPACTS IT COULD BRING FOR THE FRIDAY NIGHT THROUGH SATURDAY NIGHT TIMEFRAME. OUTSIDE THAT...A RETURN TO MORE TYPICAL SUMMER CONDITIONS ARE EXPECTED BY NEXT WEEK AFTER A BRIEF VISIT BY A LATE JULY FRONTAL BOUNDARY. ON FRI...WARM CONDITIONS WILL EXIST AS THE AREA SEES A STALLED SFC FRONT LIFT BACK NORTHWARD AS A WARM FRONT. HUMIDITY LOOKS TO BE HELD IN CHECK THANKS TO DRIER LOW LEVEL AIR IN PLACE. NO EXPECTING MUCH IN THE WAY OF CONVECTION AS WARM 850MB TEMPS LOOK TO KEEP A CAP IN PLACE AND LIMIT STORM POTENTIAL. TEMPS WILL RANGE FROM THE LOWER TO MID 90S WITH THE WARMEST READINGS ACROSS THE SOUTH HALF. BY FRI NGT AND INTO SAT...A COMPACT S/WV WILL DROP SE OUT OF THE SOUTHERN PLAINS AND LIKELY HAVE SOME SORT OF STORM COMPLEX ASSOCIATED WITH IT. MODELS HAVE BEEN CONSISTENT IN SHOWING THIS FEATURE AND CONTINUE TO DO SO. IT APPEARS THAT AFTER MIDNIGHT FRI NGT...THE NW/N HALF OF THE AREA COULD SEE THE REMNANTS OF A COMPLEX MOVE ACROSS THE AREA. MODEL DATA ALSO AGREE THAT LINGERING PRECIP CHANCES WILL EXIST ON SAT DUE TO CONTINUED EFFECTS OF LIFT AND LOW LEVEL MOISTURE CONVERGENCE. DUE TO THIS...HIGH END CHANCE TO LIKELY POPS WILL EXIST FOR THOSE TWO PERIODS. AT THIS TIME...ITS DIFFICULT TO SAY WHAT SORT OF RISK THIS ACTIVITY MAY POSE TO THE CWA. AT A MINIMUM IT SEEMS LIKE SOME STRONG STORMS AND HEAVY RAIN WILL BE POSSIBLE. HOWEVER...WILL NOT MENTION ANY RISK AT THIS TIME IN OFFICIAL PRODUCTS AND SEE HOW THINGS PLAY OUT OVER THE NEXT FEW MODEL RUNS. AS FOR TEMPS...HIGHS SAT LOOK TO BE HELD IN CHECK QUITE A BIT AS PRECIP/CLOUDS WILL KEEP READINGS QUITE A BIT BELOW AVG. FOR SAT NGT THROUGH WED...THERE WILL LIKELY BE SOME LINGERING PRECIP CHANCES FOR SAT NGT INTO SUN AS A WEAK SFC FRONT WILL BE CLOSE TO THE AREA AND SOME LINGERING MID LEVEL SHEAR STILL EXISTS FROM THE LEFT OVER TROUGH AXIS. THIS SFC FRONT MAY BRIEFLY BRING SOME LOWER DEWPTS TO THE AREA SUN INTO MON AND HELP TAKE THE EDGE OFF HUMIDITY. HOWEVER...THIS BOUNDARY LOOKS TO WASH OUT AND MORE NORMAL SUMMERTIME TEMPS/HUMIDITY SHOULD RETURN. THE PATTERN COULD BRING SOME SURPRISES AS IT WILL STILL HAVE SOME HINTS OF A NW FLOW REGIME. /CME/ && .PRELIMINARY POINT TEMPS/POPS... JACKSON 91 72 93 67 / 54 17 14 6 MERIDIAN 90 72 93 64 / 55 17 14 7 VICKSBURG 91 70 93 66 / 43 18 14 6 HATTIESBURG 90 73 94 69 / 56 22 22 14 NATCHEZ 90 72 91 69 / 38 26 21 12 GREENVILLE 90 71 91 66 / 54 15 4 7 GREENWOOD 90 70 90 64 / 58 15 5 6 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...NONE. LA...NONE. AR...NONE. && $$ DC/28/BK/CME
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON MS
506 AM CDT WED JUL 24 2013 .UPDATE...DID A QUICK UPDATE TO INCLUDE MENTION OF SOME LIGHT RAIN ACROSS THE REGION THAT CONTINUES TO EXPAND TO THE NORTH/NORTHEAST OF THE MCV OVER NE LA. A TRANSITION TO MORE SHOWERY ACTIVITY EXPECTED LATER THIS MORNING. /BK/ && .PREV DISCUSSION... /ISSUED 431 AM CDT WED JUL 24 2013/ SHORT TERM...(TODAY THROUGH THURSDAY NIGHT)... COMPLICATED NORTHWEST FLOW REGIME PERSISTS OVER THE NEXT COUPLE DAYS...ALTHOUGH THINGS WILL SIMPLIFY A TAD HEADED INTO TOMORROW AS A COOL FRONT DRIFTS INTO THE AREA FROM THE NORTH. BUT BEFORE THEN WE NEED TO DEAL WITH A RATHER UNCERTAIN FORECAST FOR TODAY. A REMNANT MCV FROM A CONVECTIVE COMPLEX THAT DIED TO OUR WEST LAST NIGHT IS CURRENTLY DRIFTING ACROSS NORTHEAST LOUISIANA TOWARD SOUTHWEST MISSISSIPPI AT THIS HOUR...WITH A BROAD CIRRUS SHIELD TRYING TO OVERSPREAD THE REGION FROM THE NORTHWEST. THESE TWO ITEMS ARE GOING TO MAKE A CONVECTIVE FORECAST FOR TODAY RATHER DIFFICULT AS CONVERGENCE IN VICINITY OF THE MCV CALLS FOR INITIATION IN ITS VICINITY ONCE WE HEAT UP...WITH EXPANSIVE UPPER CLOUD COVER LIMITING THE HEATING POTENTIAL/AT LEAST FOR THE FIRST PART OF THE DAY. FURTHER NORTH...THE SYNOPTIC COOL FRONT LOOKS TO BE PASSING INTO FAR NORTHERN MS BY LATE MORNING WHICH SHOULD PROVIDE IMPETUS FOR SOME STORMS IN ITS VICINITY AS LONG AS WE GET SOME HEATING UP THERE/BUT THERE AGAIN THE EXPANSIVE CIRRUS SHIELD IS GOING TO MAKE THAT DIFFICULT FOR SEVERAL MORE HOURS. THE BROADER SCALE MODELS DO NOT SEEM TO HAVE A GOOD HANDLE ON WHAT IS GOING ON WHICH ISN`T SURPRISING...HOWEVER THE LATEST RUNS OF THE HRRR DO LOOK REASONABLE WITH THEIR EVOLUTION OF THINGS FOR TODAY AND HAVE LOOKED TO IT MORE THAN ANYTHING FOR SOME CLUES. I WOULD NOT BE SURPRISED TO SEE THE CIRRUS THIN HEADED INTO THE DAYBREAK HOURS ALLOWING SOME DECENT HEATING TO OCCUR THIS MORNING ACROSS A GOOD MAJORITY OF THE REGION. THIS IN CONJUNCTURE WITH THE REMNANT MCV AND SURFACE FRONT SHOULD ALLOW A COUPLE FOCUS AREAS FOR STORMS TO DEVELOP...ONE ACROSS THE I-20 CORRIDOR ON THE NORTHERN FRINGE OF THE MCV AND ANOTHER NORTH OF OUR CWA INVOF THE FRONT. FROM THERE I`D EXPECT A GENERAL EXPANSION TOWARD THE SOUTH/SOUTHEAST LIKE WE`VE SEEN ACROSS THE REGION THE LAST COUPLE DAYS. THIS WOULD LEAVE A MINIMUM IN ACTIVITY ACROSS THE DELTA TODAY...HOWEVER IF THE CIRRUS THINS UP THERE AS WELL AND WE GET SOME HEATING A CONDITIONAL RISK OF STORMS FIRING IN THAT VICINITY INVOF THE FRONT LOOKS POSSIBLE. AS FOR THE STRONG/SEVERE RISK TODAY...RELIED HEAVILY ON THE LATEST RUNS OF THE RUC AND ITS TEMPERATURE PROFILE TODAY WHICH LOOKS PRETTY MEAGER ON THE LAPSE RATE FRONT GIVEN ALL THE CONVECTIVE DEBRIS/CIRRUS AROUND. COINCIDENT WITH THE UNCERTAINTY IN WHERE THE BEST COVERAGE IN STORMS WILL BE TODAY AM GOING TO LEAVE THE HWO PRETTY GENERAL WITH ALL AREAS COVERED...AND WILL OMIT MENTION OF ANYTHING SEVERE UNTIL CONFIDENCE INCREASES IN STRONGER HEATING/INSTABILITY DEVELOPING. HEADED INTO TONIGHT...I WOULD NOT BE SURPRISED TO SEE THINGS QUIET DOWN AREA WIDE BY MID TO LATE EVENING AS A LOSS OF HEATING COUPLES WITH DRIER AIR ALOFT OVERSPREADING THE CWA. ISOLATED SHOWERS AND PERHAPS A FEW RUMBLES OF THUNDER LOOK PLAUSIBLE ALONG THE ADVANCING FRONT THROUGH THE NIGHT. BY THURSDAY MORNING THE FRONT LOOKS TO BE LOCATED ALONG/JUST SOUTH OF THE I-20 CORRIDOR. THIS SHOULD CONFINE ANY SHOWER AND STORM CHANCES TO SOUTHERN ZONES...AND AT THIS POINT IT DOESN`T APPEAR STRONG STORMS WILL BE A HUGE CONCERN. WE`LL BE TAKING A LOOK AT THAT AGAIN LATER TODAY/TONIGHT. TEMPS OFFERED BY THE GFS MOS LOOKED WARM TODAY CONSIDERING THE AFOREMENTIONED CLOUDS/CIRRUS AND STORM CHANCES FOR LATER ON. ONLY OTHER NOTABLE CHANGES WERE FOR FRI MORNING WHERE TEMPS WERE RAISED A TAD TOWARD WARMER NAM/ENSEMBLE NUMBERS. /BK/ LONG TERM...(FRIDAY THROUGH WEDNESDAY)... FOCUS OF THE LONG TERM WILL BE ON A WELL DEFINED DISTURBANCE FOR SATURDAY AND WHAT SORT OF PRECIP/IMPACTS IT COULD BRING FOR THE FRIDAY NIGHT THROUGH SATURDAY NIGHT TIMEFRAME. OUTSIDE THAT...A RETURN TO MORE TYPICAL SUMMER CONDITIONS ARE EXPECTED BY NEXT WEEK AFTER A BRIEF VISIT BY A LATE JULY FRONTAL BOUNDARY. ON FRI...WARM CONDITIONS WILL EXIST AS THE AREA SEES A STALLED SFC FRONT LIFT BACK NORTHWARD AS A WARM FRONT. HUMIDITY LOOKS TO BE HELD IN CHECK THANKS TO DRIER LOW LEVEL AIR IN PLACE. NO EXPECTING MUCH IN THE WAY OF CONVECTION AS WARM 850MB TEMPS LOOK TO KEEP A CAP IN PLACE AND LIMIT STORM POTENTIAL. TEMPS WILL RANGE FROM THE LOWER TO MID 90S WITH THE WARMEST READINGS ACROSS THE SOUTH HALF. BY FRI NGT AND INTO SAT...A COMPACT S/WV WILL DROP SE OUT OF THE SOUTHERN PLAINS AND LIKELY HAVE SOME SORT OF STORM COMPLEX ASSOCIATED WITH IT. MODELS HAVE BEEN CONSISTENT IN SHOWING THIS FEATURE AND CONTINUE TO DO SO. IT APPEARS THAT AFTER MIDNIGHT FRI NGT...THE NW/N HALF OF THE AREA COULD SEE THE REMNANTS OF A COMPLEX MOVE ACROSS THE AREA. MODEL DATA ALSO AGREE THAT LINGERING PRECIP CHANCES WILL EXIST ON SAT DUE TO CONTINUED EFFECTS OF LIFT AND LOW LEVEL MOISTURE CONVERGENCE. DUE TO THIS...HIGH END CHANCE TO LIKELY POPS WILL EXIST FOR THOSE TWO PERIODS. AT THIS TIME...ITS DIFFICULT TO SAY WHAT SORT OF RISK THIS ACTIVITY MAY POSE TO THE CWA. AT A MINIMUM IT SEEMS LIKE SOME STRONG STORMS AND HEAVY RAIN WILL BE POSSIBLE. HOWEVER...WILL NOT MENTION ANY RISK AT THIS TIME IN OFFICIAL PRODUCTS AND SEE HOW THINGS PLAY OUT OVER THE NEXT FEW MODEL RUNS. AS FOR TEMPS...HIGHS SAT LOOK TO BE HELD IN CHECK QUITE A BIT AS PRECIP/CLOUDS WILL KEEP READINGS QUITE A BIT BELOW AVG. FOR SAT NGT THROUGH WED...THERE WILL LIKELY BE SOME LINGERING PRECIP CHANCES FOR SAT NGT INTO SUN AS A WEAK SFC FRONT WILL BE CLOSE TO THE AREA AND SOME LINGERING MID LEVEL SHEAR STILL EXISTS FROM THE LEFT OVER TROUGH AXIS. THIS SFC FRONT MAY BRIEFLY BRING SOME LOWER DEWPTS TO THE AREA SUN INTO MON AND HELP TAKE THE EDGE OFF HUMIDITY. HOWEVER...THIS BOUNDARY LOOKS TO WASH OUT AND MORE NORMAL SUMMERTIME TEMPS/HUMIDITY SHOULD RETURN. THE PATTERN COULD BRING SOME SURPRISES AS IT WILL STILL HAVE SOME HINTS OF A NW FLOW REGIME. /CME/ && .AVIATION... STUBBORN IFR STRATUS PLAGUING KGTR WHICH SHOULD PERSIST FOR A FEW MORE HRS BEFORE THINGS TREND VFR. ELSEWHERE VFR CONDS TO PREVAIL WITH JUST A LOW CHANCE OF SEEING SOME IFR CIG AT HBG/PIB/MEI THRU 13Z. ANOTHER ROUND OF SHRA/TSRA WL LIKELY IMPACT MOST AREAS AFTER 17Z TODAY W/THIS ACTIVITY ON THE DOWNWARD TREND THIS EVENING/ OVRNGT. SFC WINDS WL BE GENERALLY OUT OF THE W/THRU THE PERIOD AND MAY OCCASIONALLY GUST THIS AFTN. GENERALLY QUIET WX XPCTD OVRNGHT. /BK/ && .PRELIMINARY POINT TEMPS/POPS... JACKSON 91 72 93 67 / 50 17 14 6 MERIDIAN 91 72 93 64 / 56 17 14 7 VICKSBURG 91 70 93 66 / 46 18 14 6 HATTIESBURG 91 73 94 69 / 61 22 22 14 NATCHEZ 90 72 91 69 / 41 26 21 12 GREENVILLE 89 71 91 66 / 50 15 4 7 GREENWOOD 90 70 90 64 / 50 15 5 6 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...NONE. LA...NONE. AR...NONE. && $$
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
606 AM MDT WED JUL 24 2013 .AVIATION... 12Z TAF CYCLE MONSOON BURST EXPECTED TODAY AND THURSDAY AS A DEEP MONSOON MOISTURE PLUME TRACKS N AND NE ACROSS THE FORECAST AREA WITH AN EMBEDDED SUBTROPICAL PERTURBATION OR TWO. THE HRRR MODEL PROGS A WAVE OF -SHRA AND EMBEDDED TS TRACKING NORTHWARD ACROSS W AND CENTRAL NM TODAY...REACHING ABQ IN EARLY AFTN AND SAF BY LATE AFTN. AN UPPER TROUGH IS EXPECTED TO BRUSH NORTHERN PARTS OF THE STATE AS IT TRACKS E ACROSS CO TONIGHT. THIS SHOULD INVIGORATE TS ALONG THE CENTRAL MT CHAIN THIS EVENING AND SEND A CLUSTER OR LINE OF STORMS E ACROSS THE E CENTRAL AND NE PLAINS OVERNIGHT. MEANWHILE...ECMWF AND GFS SUGGEST A SLOW MOVING SUBTROPICAL PERTURBATION COULD LINGER OVER CENTRAL PARTS OF THE STATE TONIGHT KEEPING SHOWERS AND POSSIBLY AN AREA OF STRATIFORM RAIN ACTIVE. STRONGER STORMS TODAY THRU THURSDAY WILL BE CAPABLE OF PRODUCING WET MICROBURSTS WITH VERY HEAVY RAIN AND BRIEF PERIODS OF IFR CONDITIONS WITH MT OBSCURATIONS...ERRATIC WIND GUSTS OVER 45 KT AND FREQUENT/DANGEROUS LIGHTNING. 44 && .PREV DISCUSSION...308 AM MDT WED JUL 24 2013... THE AXIS OF MOIST INSTABILITY IS CENTERED SMACK DAB OVER NM THIS MORNING. LATEST WATER VAPOR LOOP SHOWS THE MONSOON PLUME FROM SOUTH TO NORTH WITH A PERTURBATION WASHING OUT ACROSS SOUTHERN NM. PWAT VALUES ARE IMPRESSIVE PER CIRA IMAGERY AND REGIONAL SOUNDINGS. THE GEFS AND SREF SOLUTIONS INDICATE THE 594DM H5 HIGH WILL SHIFT EAST INTO WEST TX TODAY AND ALLOW A RATHER WELL DEFINED PERTURBATION TO SLIDE NORTH INTO CENTRAL NM. PWAT VALUES ARE PROGGED TO AVERAGE THE 1.2-1.4 RANGE ALONG AND SOUTH OF I-40 BY THIS EVENING...WHICH IS WELL WITHIN FLASH FLOOD TERRITORY. DEEP MOIST SSE ATMOSPHERIC FLOW ALONG WITH A WEAK BOUNDARY SHIFTING SW OVER THE EASTERN PLAINS WILL SET THE STAGE FOR SOME TRAINING CELLS. A GLIMPSE OF THE 05Z HRRR SOLUTION SHOWS WIDESPREAD STORMS DEVELOPING FROM SOUTH TO NORTH TODAY. WILL HOIST A FLASH FLOOD WATCH FOR POTENTIAL RAIN RATES NEAR 2 INCHES PER HOUR. STORM MOTIONS WILL AVERAGE ABOUT 15-20 KNOTS HOWEVER CELL TRAINING MAY LEAD TO FLASH FLOODING...ESPECIALLY OVER BURN SCARS. BY THURSDAY THE UPPER HIGH REDEVELOPS OVER ARIZONA WITH LIGHT TO MODERATE NW FLOW DEVELOPING ALOFT OVER NM. THIS WILL SHIFT THE THETA-E RIDGE AXIS IN A SW-NE ORIENTATION...ALLOWING FOR MORE WIDESPREAD ACTIVITY TO SLIDE INTO THE EASTERN PLAINS DURING THE LATE AFTERNOON AND EVENING HOURS. ANOTHER FRONTAL BOUNDARY WILL SHIFT DOWN THE PLAINS THURSDAY NIGHT AND FRIDAY FOCUSING MORE HEAVY RAINFALL ALONG AND EAST OF THE CENTRAL MT CHAIN. PWAT VALUES ARE PROGGED TO FALL BELOW 1.2 FOR MOST OF THE AREA SO FLASH FLOOD THREAT MAY NOT BE AS HIGH...BUT WILL REVISIT AGAIN LATER TODAY. THE FRIDAY/SATURDAY PERIOD WILL FEATURE MOISTURE RECYCLING OVER WESTERN NM AS THE H5 HIGH SHIFTS BACK OVER CENTRAL/EASTERN NM. STORM MOTIONS WILL BECOME VERY WEAK WITH LOCALLY HEAVY RAINFALL OVER SMALLER FOOTPRINTS. POTENTIAL IS INCREASING THAT AN EXTENDED TRUE MONSOONAL BURST PATTERN WILL SET UP BY EARLY NEXT WEEK AS THE 700-500MB HIGH CENTROID SHIFTS INTO TX. THIS WILL OPEN THE DOOR TO DEEP SUBTROPICAL AND MORE HEAVY RAINFALL OVER NM. CLIMATOLOGICALLY WE ARE NOW IN THE MOST FLASHY PERIOD OF THE MONSOON SO WILL JUST CONTINUE TO TREND POPS UP INTO THE EXTENDED AS MODEL CONSISTENCY CONTINUES. GUYER .FIRE WEATHER... A WAVE OF SUBTROPICAL ORIGIN THAT HAS BEEN STATIONARY IN THE VICINITY OF EL PASO AND THE NM BOOTHEEL THE PAST COUPLE DAYS WILL FINALLY SHIFT NORTHWARD INTO CENTRAL PORTIONS OF THE FORECAST AREA TODAY AS THE 500 MB HIGH PRESSURE CENTER REPOSITIONS OVER THE TX PANHANDLE. AN UPPER TROUGH TRACKING SOUTHEASTWARD FROM THE CENTRAL ROCKIES ONTO THE CENTRAL AND SOUTHERN GREAT PLAINS TONIGHT AND THURSDAY WILL THEN SHIFT THE DIRECTION OF THE WAVE...MOVING IT EASTWARD ACROSS THE EAST CENTRAL PLAINS. ALSO...A NORTHEASTERLY WIND SHIFT THAT DEVELOPED ACROSS NE NM TUESDAY AS THE UPPER HIGH BEGAN MIGRATING TOWARD THE TX PANHANDLE FROM UT WILL PUSH THROUGH CENTRAL PARTS OF THE STATE TODAY WITH A MODESTLY GUSTY EAST CANYON WIND AND INCREASED MOISTURE. THE NET RESULT WILL BE INCREASING COVERAGE OF THUNDERSTORMS WITH HEAVY RAIN ACROSS WESTERN...CENTRAL AND NE AREAS TODAY...TONIGHT AND THURSDAY. THOUGH THUNDERSTORMS WILL LIKELY BE SPOTTIER ACROSS SE AREAS...THE STORMS THAT DO DEVELOP WILL CERTAINLY BE CAPABLE OF PRODUCING HEAVY RAINFALL. THE WETTEST PERIOD OF THIS MONSOON BURST WILL LIKELY BE TONIGHT WHEN PRECIPITABLE WATER VALUES ARE FORECAST TO VARY FROM 1 TO 1.5 INCHES ACROSS THE AREA. IN THE WAKE OF THE UPPER TROUGH CLIPPING NE NM FROM THE NW...PRECIPITABLE WATER VALUES SHOULD DROP TO AROUND THREE QUARTERS OF AN INCH ACROSS N CENTRAL AND NW AREAS THURSDAY...WHILE REMAINING RELATIVELY HIGH ELSEWHERE. TEMPERATURES TODAY AND THURSDAY WILL VARY FROM NEAR NORMAL TO AS MUCH AS 6 DEGREES BELOW NORMAL. BY FRIDAY A WEAK UPPER HIGH WILL REFORM VAGUELY OVER AZ AND NM AS THE UPPER TROUGH EXITING THE CENTRAL ROCKIES DIVES SOUTHEASTWARD INTO THE SOUTHERN GREAT PLAINS. HOWEVER...THE MONSOON MOISTURE PLUME WILL REMAIN TRAPPED UNDER THE RIDGE ALOFT AND SQUARELY OVER NM FRIDAY THROUGH THE WEEKEND. THE UPPER TROUGH WILL SEND A SECOND BACK DOOR COLD FRONT INTO THE EAST THURSDAY NIGHT AND FRIDAY. CURRENT THINKING IS THAT THIS FRONT COULD STABILIZE THINGS A BIT ACROSS THE NORTHEAST ON FRIDAY...BUT IT COULD HELP TRIGGER CONVECTION IN CENTRAL AREAS AND POSSIBLY ALSO WESTERN AREAS IF IT MAKES IT THAT FAR. THUS...THE WET WEATHER THAT BEGINS WEDNESDAY SHOULD CONTINUE FRIDAY THROUGH THE WEEKEND...ESPECIALLY CENTRAL AND WEST...THOUGH STORMS WILL SHIFT THEIR DIRECTION OF MOTION AS THE UPPER HIGH CENTER WOBBLES AROUND THE FORECAST AREA. HIGH TEMPERATURES THROUGH THE WEEKEND SHOULD REMAIN A LITTLE COOLER THAN NORMAL. GFS AND ECMWF NOW DEPICT THE 500 MB RIDGE DECREASING IN AMPLITUDE AND STRETCHING FROM CENTRAL NM TO W TX AS A STRONG OF TROUGHS IN THE WESTERLIES CROSS THE CENTRAL ROCKIES. INTERESTINGLY...MODELS KEEP THE MONSOON MOISTURE PLUME OVER THE FORECAST AREA...THOUGH IT MAY TILT FROM THE SW TO NE QUADRANTS. THUS...DAILY ROUNDS OF SCATTERED TO ISOLATED AND AT TIMES NUMEROUS STORMS WILL CONTINUE. SPOTTIER CONVECTION MAY BE FOUND ACROSS NW AREAS WHERE SOME DRIER AIR COULD ARRIVE IN THE WAKE OF SOME OF THE UPPER TROUGHS. TEMPERATURES SHOULD REMAIN NEAR AND A LITTLE BELOW NORMAL. 44 && .ABQ WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH FROM 11 AM MDT THIS MORNING THROUGH THIS EVENING FOR THE FOLLOWING ZONES...NMZ501>529-539-540. && $$
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
948 AM CDT WED JUL 24 2013 .UPDATE... A FEW TWEAKS TO TODAYS FORECAST TO REFLECT CURRENT TRENDS. THE CONVECTIVE COMPLEX ACROSS NORTH TX APPEARS TO BE REINFORCING THE COLD FRONT...NOW ACROSS THE NORTHERN SOUTH PLAINS AND ROLLING PLAINS. SHORT RANGE MODEL GUIDANCE...INCLUDING THE HRRR...TTUWRF...AND RAP ALL INDICATE THAT THIS FRONT WILL LIKELY REACH AT LEAST THE SOUTHERN PORTION OF THE CWA BY MID AFTERNOON...AND PERHAPS EVEN BEYOND AS SHOWN BY THE AGGRESSIVE ECMWF. AS A RESULT...OPTED TO SHIFT POPS SOUTHWARD TO FAVOR THE SOUTHERN ROLLING PLAINS AND SOUTH PLAINS FOR THIS AFTERNOON. CONVECTION IS EXPECTED TO REMAIN TIED TO THE BOUNDARY TODAY GIVEN SOMEWHAT WARM MID-LEVEL TEMPERATURES AND A LACK OF ANOTHER WELL- DEFINED FORCING MECHANISM...WITH THE EXCEPTION OF THE HIGH TERRAIN OF NEW MEXICO...AND AS A RESULT PORTIONS OF THE NORTHERN ROLLING PLAINS WILL LIKELY REMAIN DRY. FARTHER WEST...MORE ROBUST CONVECTIVE DEVELOPMENT IS EXPECTED ACROSS EASTERN NEW MEXICO WITHIN AN UPSLOPE FLOW REGIME...AND AT LEAST SOME OF THIS ACTIVITY IS EXPECTED TO REACH AT LEAST THE WESTERN SOUTH PLAINS LATE IN THE AFTERNOON AND INTO THE EVENING. GIVEN THE MODERATE INSTABILITY PRESENT... A FEW PULSE-TYPE THUNDERSTORMS MAY BE CAPABLE OF PRODUCING SMALL HAIL AND GUSTY WINDS... ALTHOUGH ANEMIC SHEAR WILL LIKELY PRECLUDE A WIDESPREAD SEVERE THREAT. IN ADDITION... A FEW SHOWERS AND PERHAPS A RUMBLE OF THUNDER OR TWO WILL BE POSSIBLE AS THE GUST FRONT MOVES THROUGH THE SOUTHERN ROLLING PLAINS THIS MORNING THROUGH THE EARLY AFTERNOON AS WELL. && .PREV DISCUSSION... /ISSUED 634 AM CDT WED JUL 24 2013/ AVIATION... VFR CONDITIONS EXPECTED FOR THE NEXT 24 HOURS. WEAK FRONTAL BOUNDARY WILL SAG SOUTHWARD DURING THE DAY. THERE IS SOME RISK OF TSTMS THIS AFTERNOON AND EVENING /THOUGH FAVORING KCDS/ AT BOTH TERMINALS. PREV DISCUSSION... /ISSUED 319 AM CDT WED JUL 24 2013/ SHORT TERM... FLOW OVER THE CONUS THIS MORNING IS CHARACTERIZED BY LARGE SCALE RIDGING OUT WEST AND TROUGHING ACROSS THE EAST. UPPER LEVEL HIGH HAS EXPANDED OUR WAY A BIT MORE FOR TODAY WHICH WILL HELP TEMPS RISE A FEW DEGREES. POLAR JET IS ORIENTED FROM SK TO TN. THE ASSOCIATED H5 WIND MAX IS EXPECTED TO DRIVE FARTHER SOUTH A BIT TODAY TO INCLUDE NWRN OK. AT THE SFC...A WEAK FRONTAL BOUNDARY IS SITUATED ACROSS THE NORTHERN TX PANHANDLE AND IS CURRENTLY LITTLE MORE THAN A WIND SHIFT LINE. FRONTOGENETICAL FORCING HAS BEEN INSUFFICIENT THUS FAR IN INITIATING CONVECTION. NWP APPEARS FAIRLY CONSISTENT IN PUSHING THIS BOUNDARY SLOWLY SOUTHWARD TODAY IN RESPONSE TO ANEMIC EMBEDDED TROUGH WHICH IS EVIDENT AT H5. THE QUESTION IS WHETHER DYNAMICAL PROCESSES WILL BE SUFFICIENT TO INITIATE CONVECTION ACROSS OUR CWFA THIS AFTERNOON. WHILE OUR AREA IS ON THE SUBSIDENT SIDE OF THE POLAR JET...AND SOME RESEMBLANCE OF A CAP IS EVIDENT ON FCST SOUNDINGS...THE MERE PRESENCE OF THE SURFACE CONVERGENCE WILL BE VERY HELPFUL IN HELPING TO REALIZE TSTM DEVELOPMENT. WHILE BULK SHEAR IS QUITE WEAK...INSTABILITY MAY BE SUFFICIENT FOR A FEW PULSE STRONG TO POSSIBLY SEVERE STORMS TO DEVELOP WITH HAIL TO THE SIZE OF NICKELS AND GUSTS TO AROUND 60 MPH POSSIBLE IN ANY STORMS WHICH MANAGE TO BECOME ESTABLISHED. STORM MOTION WILL BE QUITE SLOW (LESS THAN 10 MPH) AND THUS A FEW LUCKY LOCATIONS MAY PICK UP A QUICK HALF INCH TO AN INCH. HOWEVER...METEOROLOGICAL SCIENCE WITH THE OBSERVATIONAL NETWORK AVAILABLE TODAY IS INSUFFICIENT TO US TO PINPOINT WHERE THAT MIGHT BE OTHER THAN THE NORTHERN ZONES WILL HAVE THE BEST OPPORTUNITY FOR RAIN. LONG TERM... THE EXTENDED FORECAST WILL START OFF WITH CHANCES FOR PRECIP INITIALLY FOR THE SRN TX PANHANDLE/NORTHERN SOUTH PLAINS...THANKS TO A 15-25 KT NOCTURNAL LLJ AND /MOST IMPORTANTLY/ A NRLY COLD FRONT THAT WILL STALL ACROSS THE SRN TX PANHANDLE TONIGHT. THIS FRONT IS IN ASSOCIATION WITH A SUBTLE SHORTWAVE PROGGED TO MOVE SE ACROSS THE CENTRAL PLAINS. THE FRONT WILL LIKELY WASH OUT BY TOMORROW AFTN DURING AT WHICH TIME THE CENTER OF THE UA RIDGE THAT WAS ONCE OVERHEAD WOULD BE SOUTH OF THE REGION. AS SUCH...MONSOONAL STORM ACTIVITY ACROSS E NM COULD SHIFT TO ACROSS WRN ZONES DUE TO ADEQUATE SW STEERING FLOW. THURSDAY NIGHT-FRIDAY CHANCES FOR RAINFALL COULD BECOME REALIZED FOR THE REMAINDER OF THE CWA. A SHARPER SHORTWAVE TROUGH WILL BE SKIRTING SE ACROSS THE CENTRAL PLAINS HEADING TOWARDS OKLAHOMA. THIS WILL CAUSE THE UA RIDGE TO RETROGRADE JUST ENOUGH TO ALLOW FLOW ALOFT TO VEER TO THE NW. ALTHOUGH THE BEST LIFT WILL BE WELL NE OF THE REGION...THE FAVORABLE NW FLOW ALOFT WILL ENCOURAGE MOUNTAINOUS PRECIP ACTIVITY TO TRANSLATE SE ACROSS THE SOUTHERN PLAINS. THEREAFTER...A COLD FRONT WILL MOVE ACROSS THE ENTIRE CWFA FRIDAY EVENING/NIGHT...HENCE BEING ANOTHER SOURCE OF PRECIP DEVELOPMENT AS FRONTOGENETICAL FORCING WORKS WITH AN ENE UPSLOPE WIND COMPONENT. PWATS ARE PROGGED TO INCREASE TO 1.20-1.80 INCHES AND MID-LEVEL CAPE VALUES OF A FEW HUNDRED J/KG SUGGESTS THAT MODERATE RAINFALL AND ISOLATED STRONG STORMS ARE PLAUSIBLE RESPECTIVELY. THIS WEEKEND-EARLY NEXT WEEK...THE UA RIDGE ALBEIT FLATTENED...WILL MAKE A RETURN TO THE SOUTHERN PLAINS THUS CAUSING INCREASING DIFFICULTY IN STORM DEVELOPMENT /MID-LEVEL CAP WILL EXIST/. HOWEVER...ADEQUATE SW MEAN FLOW COULD ONCE AGAIN URGE THE MONSOONAL MOISTURE PLUME/PRECIP TO BEND ACROSS THE WRN AND NWRN ZONES. EARLY NEXT WEEK-MID WEEK...LONG TERM SOLUTIONS HINT AT YET ANOTHER SHORTWAVE TROUGH HAVING THE POTENTIAL TO TAKE THE EXACT SAME TRACK AS THE ONE EXPECTED THURSDAY NIGHT-FRIDAY /PER THE GFS/ OR A BIT FARTHER NE /PER THE ECMWF/. THIS WILL CAUSE THE UA RIDGE TO ONCE AGAIN RETROGRADE AND PROMOTE NW FLOW ALOFT /MOVING STORMS OFF THE MOUNTAINS AND TOWARDS THE FA/...NOT TO MENTION MAKING WAY FOR ANOTHER FRONT AND ACCOMPANIED PRECIP. WILL HOLD OFF ON MENTIONABLE POPS FOR NEXT WEEK AND AWAIT A CONSISTENT QPF SIGNAL. TEMPS WILL COOL OFF INTO THE UPPER 80S TO LOWER 90S BY THE WEEKEND...BUT WILL REBOUND BACK TO ABOVE NORM BY EARLY NEXT WEEK. && .PRELIMINARY POINT TEMPS/POPS... FRIONA 68 91 66 87 65 / 30 20 20 20 20 TULIA 70 91 66 88 65 / 20 20 20 20 20 PLAINVIEW 70 92 67 89 66 / 20 20 20 20 20 LEVELLAND 71 95 68 92 67 / 20 20 20 20 20 LUBBOCK 71 95 70 93 68 / 20 20 20 20 20 DENVER CITY 71 96 68 94 67 / 30 20 20 20 20 BROWNFIELD 72 96 68 94 68 / 20 10 20 20 20 CHILDRESS 72 97 71 94 70 / 10 20 20 20 30 SPUR 74 97 70 95 71 / 20 10 20 20 20 ASPERMONT 74 99 72 97 72 / 20 10 10 20 20 && .LUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 16/23
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
555 AM CDT WED JUL 24 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 345 AM CDT WED JUL 24 2013 MAIN FORECAST CONCERNS ARE ON SHOWER AND THUNDERSTORM CHANCES THURSDAY INTO THURSDAY NIGHT WITH THE POTENTIAL FOR SEVERE THUNDERSTORMS. FOCUS THEN TURNS TO TEMPERATURES FRIDAY THROUGH THE WEEKEND. LATEST WATER VAPOR IMAGERY SHOWED NORTHWEST FLOW ALOFT OVER THE UPPER MISSISSIPPI RIVER VALLEY EXTENDING NORTHWEST THROUGH SOUTHERN ALBERTA. SEVERAL EMBEDDED SHORTWAVES WERE NOTED WITHIN THE NORTHWEST FLOW. SURFACE OBSERVATIONS SHOWED HIGH PRESSURE IN CONTROL OVER THE REGION PROVIDING QUIET CONDITIONS. SOME MID AND HIGH LEVEL CLOUDS WERE MOVING ACROSS THE REGION EARLY THIS MORNING. THE CLOUDS COUPLED WITH THE DRIER AIR IN PLACE OVER THE REGION HAVE PREVENTED THE FORMATION OF FOG SO FAR. CANNOT RULE OUT SOME PATCHY FOG EARLY THIS MORNING BUT THIS SHOULD QUICKLY DISSIPATE AS MIXING INCREASES AFTER SUNRISE. THE HIGH WILL SLIDE EAST OF THE AREA TODAY AS A COLD FRONT SLIDES INTO THE EASTERN DAKOTAS AND EDGES EAST. SOME WEAK MOISTURE TRANSPORT COMBINED WITH 0-3KM MUCAPE VALUES OF AROUND 500 J/KG MAY BE ENOUGH TO PRODUCE ISOLATED SHOWERS AND THUNDERSTORMS OVER SOUTH CENTRAL MINNESOTA AND POSSIBLY PORTIONS OF SOUTHEAST MINNESOTA. THE BULK OF THIS ACTIVITY WILL LIKELY HAVE A DIFFICULT TIME MAKING IT EAST OF THE INTERSTATE 35 CORRIDOR AS IT ENCOUNTERS MUCH DRIER AIR. WILL HAVE TO KEEP A CLOSE EYE ON THIS...THE HRRR AND HI RES ARW ARE BOTH PRODUCING LIGHT PRECIPITATION ALONG THE I-35 CORRIDOR AND EDGES JUST EAST POSSIBLY IMPACTING DODGE AND MOWER COUNTIES DURING THE AFTERNOON HOURS. OTHERWISE...PLAN ON SOME PASSING MID AND HIGH LEVEL CLOUDS TODAY PROVIDING PARTLY SUNNY SKIES. ANOTHER DAY OF PLEASANT TEMPERATURES WITH HIGHS IN THE LOWER TO MID 70S. THE COLD FRONT CONTINUES TO ADVANCE SOUTHEAST TONIGHT AND BY THE LATE NIGHT HOURS LOOKS TO BE POSITIONED FROM THE ARROWHEAD OF MINNESOTA SOUTH THROUGH CENTRAL INTO SOUTHWEST MINNESOTA. IT THEN SLOWS AND STALLS AS IT EDGES INTO NORTHWEST WISCONSIN BY EARLY THURSDAY MORNING. 850 MB MOISTURE TRANSPORT EDGES INTO SOUTHEAST MINNESOTA AND WEST CENTRAL INTO NORTH CENTRAL WISCONSIN LATE TONIGHT INTO EARLY THURSDAY MORNING. ISOLATED SHOWERS AND THUNDERSTORMS COULD MOVE INTO THESE AREAS EARLY IN THE MORNING. OTHERWISE...PLAN ON PARTLY CLOUDY SKIES DURING THE OVERNIGHT HOURS WITH LOW TEMPERATURES RANGING FROM THE MID TO UPPER 50S. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 345 AM CDT WED JUL 24 2013 THE COLD FRONT SLIDES SOUTHEAST INTO THE FORECAST AREA ON THURSDAY AS A VIGOROUS UPPER LEVEL TROUGH DIVES SOUTHEAST OUT OF SOUTHERN MANITOBA/SASKATCHEWAN. SOUTH/SOUTHWEST FLOW INTO THE AREA AHEAD OF THE FRONT WILL HELP TO BOOST DEWPOINTS INTO THE MID TO UPPER 60S BY EARLY AFTERNOON. THE NAM SHOWS 0-3KM MUCAPE VALUES CLIMBING TO AROUND 3500 J/KG. THE GFS SHOWS SLIGHTLY LOWER VALUES IN THE 2000 TO 3000 J/KG RANGE. THE ECMWF ISN/T SO AGGRESSIVE...INDICATING VALUES IN THE 1200 TO 1600 J/KG RANGE. THE STRONGEST 0-6KM SHEAR LAGS BEHIND THE FRONT. HOWEVER...THERE LOOKS TO BE SUFFICIENT SHEAR TO SUPPORT A SEVERE THREAT WITH 0-6KM BULK SHEAR VALUES HOVERING IN THE 30 TO 35 KT RANGE THURSDAY AFTERNOON INTO THURSDAY EVENING. THUNDERSTORMS ARE EXPECTED TO DEVELOP ALONG THE FRONT THURSDAY AFTERNOON AND HEAD EAST SOUTHEAST ACROSS THE FORECAST AREA. SOME OF THESE STORMS MAY BECOME SEVERE WITH LARGE HAIL AND DAMAGING WINDS. WILL ALSO HAVE TO KEEP AN EYE ON THE POTENTIAL FOR AN ISOLATED TORNADO OR TWO WITH ANY STORMS THAT GO UP ALONG THE BOUNDARY. SHOWERS AND THUNDERSTORMS ARE LIKELY ACROSS THE AREA THURSDAY NIGHT AS THE COLD FRONT MOVES THROUGH. THE SEVERE WEATHER THREAT WILL LINGER THROUGH THE EVENING HOURS BUT SHOULD THEN WANE DURING THE OVERNIGHT HOURS AS CONVECTION BECOMES WIDESPREAD. THE FRONT FINALLY EXITS THE AREA BY FRIDAY AFTERNOON AS THE TROUGH DIVES INTO THE UPPER MISSISSIPPI RIVER VALLEY. AN UNSEASONABLY COOL AIRMASS MOVES INTO THE REGION IN THE WAKE OF THE FRONT. 850 MB TEMPERATURE STANDARDIZED ANOMALIES FALL INTO THE -2.0 TO -3.0 RANGE...INDICATIVE OF NEAR RECORD LOW MAX AND MIN TEMPERATURES. THE COLDEST AIR ALOFT MOVES OVER THE REGION DURING THE DAY ON SATURDAY...WHEN HIGHS WILL STRUGGLE TO GET OUT OF THE 60S. THE LOWEST HIGH TEMPERATURE AT LA CROSSE FOR JULY 27 IS 69 DEGREES...SET BACK IN 1981. THE LOWEST HIGH TEMPERATURE FOR ROCHESTER IS 64 AND WAS ALSO SET BACK IN 1981. LA CROSSE LOOKS TO BE VERY CLOSE TO REACHING THIS RECORD. CURRENT THINKING IS THAT LA CROSSE WILL SEE A HIGH OF 71...BUT IF THE GEM AND ECMWF VERIFY...THIS FORECAST HIGH TEMPERATURE COULD BE 3 TO 4 DEGREES HIGH. THE UPPER TROUGH WILL REMAIN OVER THE WESTERN GREAT LAKES THROUGH THE REMAINDER OF THE WEEKEND WITH COOL SURFACE HIGH PRESSURE IN CONTROL. PLAN ON HIGHS ON SATURDAY RANGING FROM THE MID 60S OVER FAR NORTHERN WISCONSIN TO AROUND 71 ACROSS FAR SOUTHWEST WISCONSIN. TEMPS WILL WARM A BIT ON SUNDAY AS THE TROUGH STARTS TO SHIFT EAST AND SURFACE WINDS TURN WESTERLY. HIGH TEMPERATURES ON SUNDAY ARE EXPECTED TO CLIMB INTO THE LOWER 70S UNDER MOSTLY SUNNY SKIES. THE UPPER TROUGH FINALLY PUSHES EAST OF THE REGION EARLY NEXT WEEK WITH FLOW ALOFT TURNING QUASI ZONAL. FORECAST MODELS SHOWING SOME DIFFERENCES IN THE HANDLING OF THE UPPER LEVEL PATTERN OVER THE CONUS. THE GFS TRIES TO BUILD A RIDGE OVER THE THE HIGH PLAINS WHILE THE ECMWF LEANS TOWARD AN ACTIVE QUASI ZONAL FLOW ALOFT WITH EMBEDDED SHORTWAVES BRINGING SHOWERS AND STORMS TO THE FORECAST AREA. HAVE LEANED TOWARD A MODEL CONSENSUS BLEND FOR THE FIRST PART OF THE WORK WEEK...WITH HIGHS WARMING TO MORE SEASONABLE VALUES WITH HIGHS IN THE UPPER 70S TO AROUND 80 AND CHANCES FOR SHOWERS AND THUNDERSTORMS MONDAY INTO TUESDAY. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 555 AM CDT WED JUL 24 2013 DRY AIR IN THE LOWER LEVELS OF THE ATMOSPHERE...ASSOCIATED WITH HIGH PRESSURE OVER THE TAF SITES...WILL HELP TO KEEP CONDITIONS VFR THROUGH TONIGHT. PERIODS OF CLOUDS ARE ANTICIPATED TO CROSS THE TAF SITES...AND SOME OF THESE COULD TRY TO PRODUCE A FEW LIGHT SHOWERS NEAR RST THIS AFTERNOON AND VERY LATE TONIGHT...BUT AGAIN CONDITIONS WILL REMAIN VFR. DID MAINTAIN A VCFG AT LSE UNTIL 13Z THIS MORNING BECAUSE OF FOG IN NEARBY RIVER VALLEYS. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...WETENKAMP LONG TERM...WETENKAMP AVIATION...AJ
AREA FORECAST DISCUSSION
NWS TUCSON AZ
125 PM MST WED JUL 24 2013 .SYNOPSIS...AN IMPULSE FROM THE EAST WILL ENHANCE THUNDERSTORM COVERAGE AND INTENSITY ACROSS MOST OF THE AREA INTO THURSDAY. SOME STORMS WILL GENERATE HEAVY RAINFALL. OTHERWISE...PLENTY OF MOISTURE TO PROVIDE A CHANCE OF MAINLY AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS INTO THE WEEKEND. && .DISCUSSION...VIS SATELLITE DATA SHOWS CLEARING ACROSS MUCH OF GRAHAM AND GREENLEE COUNTIES WITH SOME CU DEVELOPMENT OVER THE HIGH TERRAIN IN COCHISE AND SOUTHWEST GRAHAM COUNTIES. SEVERAL VALLEY LOCATIONS ACROSS THE EASTERN COUNTIES ARE IN THE UPPER 80S TO LOW 90 RANGE...WHEREAS WESTERN PIMA AND SANTA CRUZ COUNTIES ARE LARGELY CLOUDED OVER WITH RELATIVELY COOL CONDITIONS IN PLACE. THE BETTER HEATING IN THE EAST STILL SUGGESTS A THREAT FOR CONVECTION THROUGH THE AFTERNOON AND EVENING. HOWEVER...THE CLOUDY COOLER COOLER CONDITIONS ELSEWHERE COMBINED WITH A WARM LAYER AT AROUND 450 TO 500 MB SHOULD KEEP STRONG CONVECTION LIMITED OVER PIMA/SANTA CRUZ AREAS. THE 18Z HRRR RUN HAD THE BEST HANDLE ON THE CLOUD COVER SO FAR AND KEEPS ACTIVITY RELATIVELY LIMITED THROUGH THE REST OF THE AFTERNOON. HOWEVER...THERE ARE SIGNS OF INCREASING ACTIVITY OVERNIGHT IN THE FORM OF AN MCS DEVELOPING OVER WESTERN NEW MEXICO AND DRIFTING SOUTHWEST ACROSS AZ. GIVEN THE OUR WEAK LOW PRESSURE SYSTEM IS STILL HANGING AROUND SE ARIZONA SO THIS WOULD MAKE OVERNIGHT CONVECTION A REASONABLE SOLUTION. GIVEN THE SATURATED GROUND CONDITIONS IN THE EASTERN ZONES...THE FLASH FLOOD WATCH STILL APPEARS WARRANTED. WE ARE ALSO CLOSELY MONITORING THE SAN FRANCISCO AND GILA RIVERS ACROSS GRAHAM AND GREENLEE COUNTIES. THERE ARE QUICK RESPONSE CHANNELS IN OUR CWA AND IT WILL NOT TAKE MUCH RAINFALL IN THAT AREA TO CAUSE RAPID RISES. THE TROUGH AXIS OF THE WEAK UPPER LOW LAYS OVER SE ARIZONA TOMORROW AS WELL AND MAY AGAIN SERVE AS A SOURCE OF LIFT FOR ACTIVITY. MODELS ARE SUGGESTING ANOTHER WET DAY POSSIBLE TOMORROW WITH THE FOCUS MAINLY ALONG THE INTERNATIONAL BORDER AND HIGHER TERRAIN. WE SHOULD ALSO SEE A RETURN OF SOUTHERLY FLOW ALOFT TOMORROW ALONG WITH SUSTAINED MID LEVEL MOISTURE. THE MONSOON RIDGE BEGIN A MODIFICATION PROCESS TOMORROW AS WELL. INITIALLY...THE RIDGE AXIS AMPLIFIES OVER THE WESTERN US THROUGH FRIDAY...KEEPING SE ARIZONA IN FAVORABLE FLOW FOR THUNDERSTORMS. HOWEVER...STARTING LATE SATURDAY...THE RIDGE BEGINS THE FLATTEN AND SHIFT SOUTHEAST. THE FLOW ALOFT OVER ARIZONA BECOME MORE WESTERLY AND STAYS WESTERLY THROUGH MONDAY. THE HIGH CONTINUES DRIFTING SOUTH THROUGH MIDWEEK AND WHILE OUR FLOW ALOFT BACKS TO THE SOUTH...WE REMAIN FAIRLY DRY INT THE MIDLEVELS. SO WE MAY HAVE A DECENT BREAK IN THUNDERSTORM ACTIVITY STARTING SUNDAY AND LASTING FOR SEVERAL DAYS. THAT MEANS WARMER TEMPERATURES TOO. GFS/ECWMF DID SHOW ANOTHER INVERTED TROUGH MOVING WEST ACROSS NORTHERN MEXICO MID WEEK BUT THEY KEEP THE ENERGY FAR ENOUGH SOUTH THAT PRECIP CHANCES WOULD BE LIMITED OVER ARIZONA. JJB && .AVIATION... SCT TO NUMEROUS TSRA /SHRA CONTINUING THRU 25/06Z...THEN BECOMING MAINLY ISOLD. MVFR CONDITIONS WITH WIND GUSTS APPROACHING 45 KTS WITH THE STRONGEST TSRA. OTHERWISE...CLOUD DECKS MAINLY 6-12K FT AGL AND SURFACE WIND GENERALLY LESS THAN 10 KTS THRU THURSDAY MORNING OR 25/18Z. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS. && .FIRE WEATHER...ENHANCED MOISTURE WILL PROVIDE A BETTER CHANCE OF SHOWERS AND THUNDERSTORMS THROUGH THURSDAY EVENING. OTHERWISE...SOUTHEAST ARIZONA WILL KEEP ENOUGH MOISTURE AROUND FOR MAINLY AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS TO CONTINUE INTO EARLY NEXT WEEK. && .TWC WATCHES/WARNINGS/ADVISORIES...FLASH FLOOD WATCH FROM 11AM UNTIL 9 PM MST FOR AZZ507>514. && $$ VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
157 PM EDT WED JUL 24 2013 .PREV DISCUSSION... /ISSUED 720 AM EDT WED JUL 24 2013/ SHORT TERM /TODAY THROUGH THURSDAY/... /ISSUED AT 349 AM EDT WED JUL 24 2013/ A VERY ACTIVE WEATHER PATTERN WILL PERSIST TODAY WITH CURRENT SATELLITE WATER VAPOR IMAGERY SHOWING A SHARP UPPER SHORT WAVE OVER SE GA AND DEPARTING EASTWARD... AND A SERIES OF MORE SUBTLE DISTURBANCES EMBEDDED WITHIN THE NW FLOW ALOFT BACK TO THE WEST AND NW. REGIONAL RADAR SHOWS ISOLATED STORMS ACROSS WESTERN AL... AND THIS ACTIVITY IS ASSOCIATED WITH A WEAK DISTURBANCE PUSHING ACROSS WEST TN AND NORTH MS. FURTHER WEST... SATELLITE AND RADAR SHOW A LARGE CONVECTIVE COMPLEX ACROSS WESTERN OK/AR... AND DROPPING SSE ON A TRAJECTORY FOR THE SE TX AND LA COASTS. SURFACE ANALYSIS SHOWS A WEAK FRONTAL BOUNDARY PUSHING INTO NW TN AND EXTENDING NEWD INTO VA. SHORT RANGE MODELS SHOW THESE SUBTLE DISTURBANCES TO THE WEST INTERACTING WITH A MOIST /1.8+ PW/ AND MODERATELY UNSTABLE /2000-2500 CAPE/ AIR MASS OVER GA TO PRODUCE SCATTERED SHOWERS AND THUNDERSTORMS AGAIN TODAY... MAINLY DURING THE AFTERNOON AND EVENING HOURS. THE GREATER CHANCES APPEAR TO BE ACROSS NORTH GA AHEAD OF THIS SAGGING COLD FRONT... AND AGAIN ACROSS THE WESTERN ZONES WHERE THE LOCAL WRF MODEL SHOWS ANOTHER CONVECTIVE COMPLEX DIVING SOUTHWARD ACROSS AL AND BRUSHING THE WESTERN COUNTIES DURING THE AFTERNOON. THE HRRR MODEL SHOWS MORE CONVECTION CONCENTRATED ALONG AND AHEAD OF THE APPROACHING COLD FRONT THAT PUSHES INTO NORTH GA BY EARLY-MID AFTERNOON. EXPECT THIS ACTIVITY TO PUSH SOUTH INTO CENTRAL GA DURING THE LATE AFTERNOON AND EVENING HOURS. THEREFORE... IT APPEARS STORMS COULD DEVELOP JUST ABOUT ANYWHERE TODAY. THE SLIGHTLY COOLER AND DRIER AIR ALOFT ASSOCIATED WITH THE NW FLOW CONTINUES TO SUGGEST A THREAT OF STRONG DOWNBURST WINDS AND LARGE HAIL THIS AFTERNOON AND EVENING DURING PEAK HEATING. THIS IS ALSO SUPPORTED BY SPC...WHO HAS BLANKETED A FIVE PERCENT CHANCE OF WIND AND HAIL THREAT ACROSS THE ENTIRE FORECAST AREA TODAY. ALL WARRANTS MENTION OF ISOLATED SEVERE STORMS... WITH LOCALLY HEAVY RAIN... DAMAGING WINDS AND LARGE HAIL IN THE HAZARDOUS WEATHER OUTLOOK FOR TODAY. MODELS SHOW STORM COVERAGE GREATLY DIMINISHING BEFORE MIDNIGHT WITH LOSS OF DAYTIME HEATING. SHORT RANGE MODELS AGREE ON SAGGING THE FRONT ACROSS NORTH GA OVERNIGHT WITH SOME DRIER AIR SPREADING DOWN INTO THE ATLANTA AREA EARLY ON THURSDAY. THIS SHOULD HOLD CONVECTION DOWN TO ISOLATED OR LESS FOR MUCH OF NORTH GA TO INCLUDE THE ATLANTA METRO AREA ON THURSDAY. EXPECT MORE SCATTERED CONVECTION ACROSS THE FAR NE AND CENTRAL ZONES WHERE MODELS SHOW CONVECTION FIRING ALONG AND OUT AHEAD OF THE NEARLY STATIONARY FRONT. COULD SEE A FEW STRONG TO SEVERE STORMS ACROSS THE FAR SOUTH AND SE ZONES THURSDAY AFTERNOON WHERE THE FRONT AND GREATER INSTABILITIES ARE EXPECTED. AS FOR TEMPS... LEANED TOWARD A BLEND BETWEEN PERSISTENCE AND THE SLIGHTLY WARMER MAV THROUGH THE SHORT TERM. 39 LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... /ISSUED AT 349 AM EDT WED JUL 24 2013/ NO REAL CHANGES TO THE PREVIOUS MODEL TRENDS THROUGH THE EXTENDED FORECAST PERIOD. FAIRLY GOOD AGREEMENT AMONG THE MEDIUM RANGE MODELS THROUGH THE WEEKEND AS FAR AS THE LARGER SCALE FEATURES ARE CONCERNED WITH A PERSISTENT EASTERN U.S. UPPER TROUGH DOMINATING THE REGIONAL WEATHER. EXTENDED FORECAST PERIOD STARTS OUT IN A BIT OF A QUIET PERIOD AS THE MAIN UPPER TROUGH AXIS IS EAST OF THE STATE... WITH SCATTERED...MAINLY DIURNAL...CONVECTION EXPECTED THROUGH FRIDAY. WEAK NORTHWESTERLY UPPER FLOW WILL KEEP A CHANCE FOR A ROUND OR TWO OF MORE ORGANIZED CONVECTION ASSOCIATED WITH ANY WEAK RIPPLES RIDING DOWN THE BACKSIDE OF THE TROUGH...BUT NO DISTINCT SHORT WAVE IS EVIDENT IN THE MODELS AT THIS TIME. FOR THE WEEKEND...A NEW SHORT WAVE DIGS INTO THE MID-SOUTH FRIDAY NIGHT AND SWEEPS ACROSS THE REGION SATURDAY. GFS/ECMWF/CMC/NAM ARE SURPRISINGLY SIMILAR WITH THIS FEATURE SO I WILL BE BUMPING UP SATURDAY/S POPS INTO THE LIKELY RANGE. FOR NOW THE MODELS ARE ONLY SHOWING A WEAK SURFACE BOUNDARY ASSOCIATED WITH THIS FEATURE. ALTHOUGH INSTABILITY IS FORECAST TO REMAIN MODERATE AT BEST SATURDAY...SOME WEAK SHEAR IS EVIDENT SO CONVECTION MAY BE A BIT MORE ORGANIZED AND AT LEAST A SMALL INCREASE IN THE POTENTIAL FOR SEVERE STORMS WILL NEED TO BE WATCHED WITH THIS SYSTEM. WEAK SURFACE TROUGHING AND WEAK UPPER LEVEL FLOW SETTLE IN FOR THE REMAINDER OF THE EXTENDED FORECAST PERIOD. MODELS ARE SHOWING A SIGNIFICANT REDUCTION IN DEEPER LAYER MOISTURE THURSDAY NIGHT AND FRIDAY...BUT AMPLE LOW-LEVEL MOISTURE REMAINS AVAILABLE FROM THE MOIST SURFACE CONDITIONS FOR SCATTERED CONVECTION. BETTER DEEP MOISTURE ACCOMPANIES THE SYSTEM SATURDAY. A FAIRLY STRONG MOISTURE GRADIENT SETS UP FOR THE BALANCE OF THE PERIOD INTO THE MIDDLE OF NEXT WEEK WITH RELATIVELY DRY AIR ACROSS THE NORTH. HOWEVER...IN THE ABSENCE OF A STRONG UPPER RIDGE THERE SHOULD BE SUFFICIENT MOISTURE AVAILABLE FOR ISOLATED TO SCATTERED...MAINLY DIURNAL...CONVECTION AREA-WIDE EACH DAY WITH AT LEAST SLIGHTLY BETTER CHANCES ACROSS CENTRAL GEORGIA. EXCEPT FOR SATURDAY WITH THE INCREASED CLOUD COVER AND PRECIPITATION EXPECTED...TEMPERATURES ARE EXPECTED TO REMAIN AROUND SEASONAL NORMALS THROUGH THE EXTENDED FORECAST PERIOD. 20 .AVIATION... 18Z UPDATE... INTERMITTENT PERIODS OF MVFR CEILINGS ARE STILL AFFECTING SOME OF THE METRO TAF SITES. THESE PERIODS APPEAR TO BE SHORT LIVED AND ARE EXPECTED TO SCATTER OUT THIS AFTERNOON. MAIN CONCERN FOR THE PERIOD IS CONVECTION. AN AREA OF CONVECTION TO THE WEST WILL AFFECT CSG SHORTLY. OTHER CONVECTION APPEARS POSSIBLE MOVING FROM NORTH TO SOUTH TODAY AS A COLD FRONT MOVES INTO THE AREA. STORMS COULD BE STRONG AND A SEVERE WIND GUST CANNOT BE RULED OUT. //ATL CONFIDENCE...18Z UPDATE... MEDIUM CONFIDENCE ON TIMING OF CONVECTION...HIGH ON ALL OTHER ELEMENTS. ARG && .PRELIMINARY POINT TEMPS/POPS... ATHENS 90 70 89 69 / 40 50 40 20 ATLANTA 87 71 88 71 / 50 50 20 10 BLAIRSVILLE 84 65 81 62 / 50 50 20 20 CARTERSVILLE 87 67 88 66 / 50 50 20 10 COLUMBUS 90 72 92 71 / 50 50 20 10 GAINESVILLE 87 70 87 68 / 50 50 30 20 MACON 90 71 92 71 / 50 50 40 20 ROME 88 68 89 66 / 50 40 20 10 PEACHTREE CITY 88 67 89 67 / 50 50 20 10 VIDALIA 89 73 92 72 / 30 50 40 20 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...ARG LONG TERM....20 AVIATION...ARG
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1239 PM CDT WED JUL 24 2013 .UPDATE... ISSUED AT 1001 AM CDT WED JUL 24 2013 SATELLITE HAS A RESPECTABLE SHORTWAVE DROPPING SOUTHEAST INTO IOWA. THE SLIGHTLY BETTER LIFT IS ACROSS MINNESOTA WERE SOME SHOWERS WERE OCCURRING AROUND KSTC. THIS PRECIPITATION AND THE SPRINKLES AT KDEH ARE IN AN AREA OF CONVERGENCE AND ISENTROPIC LIFT. THE RAP TRENDS INDICATE THIS ISENTROPIC LIFT WILL TURN MORE INTO DOWN GLIDE AS THE LATE MORNING AND AFTERNOON PROGRESS ACROSS THE AREA. THUS THE CLOUDS ASSOCIATED WITH THE SHORTWAVE SHOULD THIN WITH TIME. HOWEVER...THE VERY WEAK CONVERGENCE WILL PERSIST THROUGH MID AFTERNOON SO ONE CANNOT RULE OUT ISOLATED POCKETS OF SPRINKLES. THERE SHOULD BE A FAIR AMOUNT OF VIRGA ASSOCIATED WITH THE CLOUDS. ..08.. && .SYNOPSIS... ISSUED AT 338 AM CDT WED JUL 24 2013 CANADIAN HIGH PRESSURE OVER ND AND NORTHERN MN WAS THE DOMINANT SURFACE FEATURE OVER THE REGION EARLY THIS MORNING. RESULTING DRY AIR AND SUBSIDENCE WAS RESULTING IN MOSTLY CLEAR SKIES ACROSS THE NORTHERN HALF OF THE FORECAST AREA. ACROSS THE SOUTH...SATELLITE IMAGERY REVEALED A DECK OF AC EXPANDING ACROSS SE IA INTO W CENTRAL IL AND A SHIELD OF CI...ASSOCIATED WITH A VERY LARGE MCS OVER OK AND AR...REACHING INTO FAR NORTHEAST MO. LIGHT NE WINDS WERE ADVECTING DEWPOINTS IN THE 50S INTO THE AREA...WHILE TEMPERATURES WERE COOLING TOWARD ANTICIPATED LOWS IN THE LOWER 50S NORTHEAST TO NEAR 60 IN THE FAR SOUTH. ALOFT...A NW FLOW BETWEEN A CENTRAL ROCKIES RIDGE AND TROUGH OVER THE EASTERN U.S. REMAINED IN PLACE. THE NEXT UPSTREAM SHORTWAVE WAS MOVING ACROSS SOUTH DAKOTA...ON A TRACK TO MOVE THROUGH THE FORECAST AREA TODAY. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 338 AM CDT WED JUL 24 2013 THE MAIN FOCUS IS ON CONTINUED BELOW NORMAL TEMPERATURES AS HIGH PRESSURE KEEPS A COOL...DRY AIRMASS IN PLACE. THE HIGH PRESSURE RIDGE IS EXPECTED TO PASS TO THE NORTHEAST TO EXTEND FROM LOWER MI SW INTO MO BY THURSDAY MORNING. WHILE THIS WILL PROVIDE LOW LEVEL SUBSIDENCE AND A FEED OF DRY AIR ON LIGHT EAST TO NORTHEAST WINDS. AN ACTIVE UPPER LEVEL NW FLOW AND THE EMBEDDED SHORTWAVE AND AXIS OF MID LEVEL MOISTURE MOVING OUT OF THE NORTHERN PLAINS WILL LIKELY RESULT IN PASSING MID LEVEL CLOUDS THAT COULD BE RATHER EXTENSIVE AROUND LATE MORNING THROUGH EARLY AFTERNOON OVER ESPECIALLY THE NORTH. THE LIMITED INSOLATION DURING PEAK HEATING...ALONG WITH A MORE EASTERLY SURFACE WIND COMPONENT AND COOLER MORNING START SUPPORTS SLIGHTLY COOLER HIGHS THAN YESTERDAY AND HAVE STAYED WITH A RANGE FROM THE LOWER 70S NORTH TO UPPER 70S SOUTH. MODEST MID LEVEL LIFT MAY AGAIN LEAD TO HIGH BASED SHOWERS OVER THE ESPECIALLY THE NORTH IN THE AFTERNOON...BUT MUCH LIKE YESTERDAY...WILL KEEP A DRY FORECAST ANTICIPATING LITTLE MORE THAN VIRGA. TONIGHT...MID LEVEL SUBSIDENCE IS SHOWN OVERSPREADING THE REGION...WHICH ALONG WITH THE PASSING SURFACE RIDGE AXIS SHOULD PROVIDE MOSTLY CLEAR SKIES AND LIGHT WINDS. MIN TEMPERATURES FROM THE PREVIOUS FORECAST IN MID TO UPPER 50S LOOK ON TRACK AND ONLY MINOR TWEAKS WERE MADE. THESE VALUES WOULD BE ROUGHLY A CATEGORY ABOVE RECORD LOWS FOR THE 25TH...WHICH ARE INCLUDED IN THE CLIMATE SECTION BELOW FOR REFERENCE. CANNOT RULE OUT GROUND FOG AS WINDS WILL BE LIGHT TO NEARLY CALM TOWARD SUNRISE...BUT DO NOT EXPECT ENOUGH COVERAGE OR IMPACTS TO WARRANT MENTION IN THE FORECAST. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 338 AM CDT WED JUL 24 2013 FOCUS IN THE EXTENDED IS ON TIMING AND AMOUNTS OF PCPN CHANCES FOR THURSDAY NIGHT THROUGH FRIDAY NIGHT. TWO SEPARATE AREAS OF LOW PRESSURE...ONE MOVING ACROSS THE UPPER MS RIVER VALLEY AND THE OTHER IN THE SOUTHERN PLAINS...WILL INTERACT WITH ONE ANOTHER AS THE NORTHERN LOW SWEEPS A COLD FRONT THROUGH THE AREA ON FRIDAY. THE SOUTHERN SYSTEM MAY STEAL SOME ENERGY/MOISTURE AS MODELS SHOW IT TO MOVE ESE ACROSS CENTRAL/SOUTHERN MO. DO BELIEVE MOST AREAS/NW TWO THIRDS/ WILL SEE A GOOD CHANCE /50POP/ OF RAIN BUT AM NOW THINKING THAT THE ENERGY/PCPN MAY BE SHEARING OUT AS THE FRONT MOVES INTO THE SE THIRD OF THE CWFA AND THE SOUTHERN LOW FOCUS/S HEAVIER RAINS ACROSS MO. THUS LEFT LOWER 35-40 POPS AND PCPN AMOUNTS IN SE. STEPPED OUT PCPN CHANCES FRIDAY EVENING...WITH LINGERING SLIGHT CHANCES IN SE AFTER MIDNIGHT. THIS MAY BE TOO SLOW AND ALL PCPN MAY BE DONE BY LATE EVENING. ALL IN ALL...RAINFALL TOTALS LOOK TO RANGE FROM AROUND A THIRD OF AN INCH IN THE NW...TO A TENTH OF AN INCH SE. SEASONABLY COOL AND DRY CONDITIONS WILL BE FOUND ACROSS THE AREA FOR THE WEEKEND. TEMPERATURES WILL BE IN THE UPPER 70S/LOWER 80S ON THURSDAY...WITH MID 70S TO LOWER 80S ON FRIDAY AS SHOWERS AND STORMS MOVE THROUGH. MILD LOWS THURSDAY NIGHT /L-M 60S/ AS MOISTURE BUILDS AHEAD OF FRONT. BEHIND THE FRONT MUCH COOLER AIR IS FOUND. SATURDAY MORNING LOWS WILL SLIP INTO LOWER 50S NW TO NEAR 60 SE...WITH HIGHS SATURDAY AFTERNOON STRUGGLING TO REACH 70 NORTH TO THE UPPER 70S SOUTH. SUNDAY AM LOWS LOOKS TO BE COLDEST...WITH READINGS GENERALLY 53-58 DEGREES. A GRADUAL WARM UP BEGINS SUN THROUGH TUE WITH HIGHS IN THE MID 70S TO LOWER 80. THE NEXT CHANCE FOR RAIN COMES IN MONDAY THROUGH TUESDAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1234 PM CDT WED JUL 24 2013 A FEW POCKETS OF MVFR CIGS DEVELOPED WITH THE DIURNAL CUMULUS ACROSS IOWA. MOST CIGS ARE ABOVE 3KFT AGL. THUS VFR WX WILL CONTINUE THROUGH 06Z/25 WITH HIGH PRESSURE ACROSS THE AREA. AFT 06Z/25 THE POTENTIAL EXISTS FOR SHALLOW GROUND FOG TO DEVELOP. MVFR VSBYS AND BLO 0.5KFT AGL CLOUDS WERE INTRODUCED PRIOR TO SUNRISE IN THE 18Z TAFS. ..08.. && .CLIMATE... ISSUED AT 338 AM CDT WED JUL 24 2013 RECORD LOWS FOR JULY 25... MOLINE.........52 IN 1933 CEDAR RAPIDS...50 IN 2004 DUBUQUE........50 IN 2004 BURLINGTON.....53 IN 1911 && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ UPDATE...08 SYNOPSIS...SHEETS SHORT TERM...SHEETS LONG TERM...14 AVIATION...08 CLIMATE...SHEETS
AREA FORECAST DISCUSSION
NWS GRAY ME
442 PM EDT WED JUL 24 2013 .SYNOPSIS... A COLD FRONT WILL STALL OFFSHORE TONIGHT. HIGH PRESSURE WILL BUILD IN FROM THE WEST THROUGH THURSDAY. HIGH PRESSURE WILL HOLD NEAR THE REGION FRIDAY MORNING. LOW PRESSURE WILL TRACK NORTH ALONG THE THE FRONT FRIDAY AFTERNOON THROUGH EARLY SATURDAY. ANOTHER SYSTEM WILL APPROACH FROM THE WEST SATURDAY NIGHT AND SUNDAY. UNSETTLED WEATHER CONTINUES INTO EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... AS EXPECTED STRONG HEATING OVER THE MIDCOAST AND DELAYED FRONTAL PUSH THERE HAS ALLOWED ENOUGH INSTABILITY TO DEVELOP FOR STRONGER TSTMS THIS AFTERNOON. WITH FNT CROSSING THE COAST ATTM ELSEWHERE...THE ONLY REMAINING TSTM THREAT IS FOR THE WALDO...LINCOLN...AND KNOX COUNTY AREAS. STORM HEIGHT IS NOT OVERLY IMPRESSIVE...BUT PCPN LOADING IN THE COLUMN AND MARGINAL LLVL LAPSE RATES A STRONG WIND GUST OR TWO IS PSBL. THEN MUCH COOLER DEW POINTS FILTER INTO THE REGION FROM THE NW. THIS COUPLED WITH CLEARING AND WEAKENING WINDS WILL SUPPORT A COMFORTABLE NIGHT WITH LOW FALLING INTO THE 40S AND LOWER 50S. PATCHY VALLEY FOG IS PSBL GIVEN THE RECENT RNFL AND COOL TEMPS. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/... UPDATE... JUST A FEW MINOR TWEAKS TO THE GRIDS TO BLEND WITH 20Z OBSERVATIONS. CLEARING CONTINUES DOWNWIND OF THE ME/NH MOUNTAINS LATE THIS AFTERNOON. WNW FLOW IS ALSO PUSHING ANY MARINE FOG EAST OF OUR WATERS THIS HOUR. CONVECTION HAS SHIFTED EAST...AND NOW ALL THE PCPN IS OVER EASTERN MAINE. LATEST HRRR RUN KEEPS ANY NEWLY DEVELOPING SHOWER ACTIVITY JUST EAST OF OUR COASTAL WATERS THIS EVENING. PREV DISC... HIGH PRES BUILDING IN FROM THE W WILL BRING PLEASANT CONDS ON THU. EXPECT MOSTLY SUNNY SKIES...ESPECIALLY AWAY FROM THE COAST. THE STALLED FRONTAL BOUNDARY WILL PROVIDE LINGERING CLOUDS NEAR AND JUST OFFSHORE. WIDESPREAD HIGHS IN THE 70S ARE EXPECTED...WITH LOW HUMIDITY. THU NIGHT WEAK WAVE OF LOW PRES WILL BEGIN TO RIDE ALONG THE FNT. ESPECIALLY LATE IN THE PERIOD SHRA WILL BE PSBL ACROSS SE NH AND SW ME. THE INLAND EXTENT OF SHRA REMAINS IN QUESTION AS NWP CONTINUES TO ADVERTISE BOTH INLAND LOW PRES TRACKS AND THOSE WELL OUT TO SEA. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... BIG QUESTION MARK FOR FRIDAY ON WHETHER A DEVELOPING COASTAL LOW MOVING NORTH SPREADS RAIN WELL INLAND OR KEEPS MOST OF THE RAIN OFF THE COAST. NAM/GFS DIFFER GREATLY IN POSITION OF THE COASTAL LOW BY FRIDAY EVENING WITH THE NAM MUCH FURTHER WEST AND ALSO IMPLYING HEAVY RAINS FOR MUCH OF THE FA WHILE THE GFS KEEPS THE HVY RAIN OFFSHORE WITH ONLY SOME LIGHT RAINS SKIRTING SRN/ERN AREAS OF CWA. FOR NOW WILL HAVE TO LEAN MORE TOWARD THE GFS WITH THE SYSTEM FURTHER E, THIS ALSO GOES ALONG THE EURO THINKING. THE NAM SEEMS TO BE THE OUTLIER FOR NOW. THE SYSTEM EXITS BY SATURDAY WITH CLEARING BY AFTERNOON. A MEAN L/WV TROF CENTERED NEAR THE GREAT LAKES ALLOWS YET ANOTHER S/WV TO ROTATE NEWD INTO NEW ENGL BY SUNDAY WITH MORE RAIN PSBL THAT WILL KEEP UNSETTLES WX INTO MON AS WELL. BY TUES THE TROF OVER THE GT LAKES KICKS OUT NEWD ALLOWING A DRIER WLY FLOW TO RETURN FOR THE MIDWEEK TIME FRAME. OVERALL TEMPS TO BE NEAR OR SLIGHTLY BELOW SEASONAL LEVELS. USED A BLEND OF THE MAV/MET GUID FOR 4TH/5TH PDS AND THEN A BLEND OF THE ADJUSTED MEX GUID FOR THE OUTLOOK PD. && .AVIATION /21Z WEDNESDAY THROUGH MONDAY/... SHORT TERM...LOCAL MVFR/IFR CONDS ARE PSBL INVOF KRKD EARLY THIS EVENING BEFORE VFR CONDS PREVAIL THRU THE OVERNIGHT. PATCHY VALLEY FOG IS PSBL AFTER THE RECENT RNFL AND COOLER WX EXPECTED TONIGHT. LOCAL IFR IN FOG IS PSBL IN THE FAVORED LOCATIONS. LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/... CONDS LWRG TO MVFR/IFR LATE FRI INTO EARLY SAT IN DEVELOPING AREAS OF RAIN ESPECIALLY OVER ERN/SRN AREAS. CONDS WILL IMPROVE TO VFR SAT BUT LOWER AGAIN TO MVFR/IFR CONDS SAT NIGHT AND INTO SUNDAY. && .MARINE... SHORT TERM...WINDS AND SEAS ARE EXPECTED TO REMAIN BLO SCA THRESHOLDS. LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...SCA CONDS DUE TO SEAS MAY OCCUR FRI INTO SAT DUE TO SEAS AS A COASTAL LOW PASSES OFF TO THE EAST WITH WINDS TO MAINLY REMAIN BLO SCA CONDS. WINDS/SEAS SHOULD REMAIN BLO SCA CONDS FOR SUNDAY INTO NEXT WEEK. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...NONE. NH...NONE. MARINE...NONE. && $$
AREA FORECAST DISCUSSION
NWS CARIBOU ME
333 PM EDT WED JUL 24 2013 .SYNOPSIS... HIGH PRESSURE WILL BUILD ACROSS THE REGION THURSDAY. A WEAK AREA OF LOW PRESSURE WILL APPROACH FROM THE SOUTH FRIDAY. && .NEAR TERM /THROUGH THURSDAY/... A FRONT SYSTEM IS EXPECTED TO MOVE TO SOUTH AND EAST OF THE AREA BY EARLY THIS EVENING. SHOWERS AND THUNDERSTORMS ARE EXPECTED TO END QUICKLY BEHIND THE FRONT FOLLOWED BY CLEARING. FOR POPS HAVE USED THE RUC13 INTO EARLY EVENING THEN TRANSITION TO A BLEND THE NAM12..GFS40 ..SREF..CMCREG AND ECMWF. FOR WIND HAVE BLENDED THE NAM12 AND MOSG25 AND WILL USE 150 PERCENT OF SUSTAINED WIND FOR GUSTS. MOSG25 TEMPERATURE LOOKS TOO COLD TONIGHT...ESPECIALLY IN NORTH BUT MAXIMUM TEMPERATURE THURSDAY LOOK REASONABLE SO WILL NOT MAKE ANY CHANGES FROM PREVIOUS FORECAST. && .SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/... THROUGH THE THURSDAY NIGHT TO SATURDAY TIME FRAME...A BROAD MID- UPPER LEVEL TROUGH...TRYING TO DEVELOP A CLOSED LOW...WILL BE SITUATED IN THE GENERAL VICINITY OF THE GREAT LAKES. FOR MAINE...SOUTHWEST FLOW TO THE EAST OF THE TROUGH WILL CARRY EMBEDDED SHORTWAVES INTO AND ACROSS THE REGION. GFS/EC/NAM ALL INDICATE A DEVELOPING LOW PRESSURE SYSTEM WILL RIDE UP ALONG THE COAST AND APPROACH SOUTHERN MAINE ON FRIDAY. MODEL SOLUTIONS DO NOT HOLD TOGETHER PAST THAT POINT...WITH EACH BRINGING THAT LOW ACROSS THE REGION AT DIFFERENT TIMES. GFS IS FASTEST...BRINGING THE LOW INTO THE BAY OF FUNDY AROUND 06Z SATURDAY. THE EC IS THE SLOWEST AT ABOUT 12 HOURS LATER. THE NAM IS BETWEEN THE TWO TIMING-WISE BUT FARTHER NORTH. SINCE THIS IS APPROACHING DAY 4 AND THEY ARE ALL IN THE SAME GENERAL REGION...WILL GO WITH A BLEND. SHOWERS MAY MOVE INTO DOWNEAST SECTIONS OF MAINE BY THURSDAY NIGHT...OVERSPREADING MAINLY CENTRAL AND EASTERN SECTIONS OF MAINE ON FRIDAY. THE BEST CHANCE FOR RAIN WILL BE LIKELY BE LATE FRIDAY INTO EVENING FOR SOUTHEAST MAINE. TEMPERATURES WILL BE ON THE MILD SIDE IN THE LOWER TO MID 70S FRIDAY WITH ABUNDANT CLOUD COVER OVERSPREADING THE REGION AND SHOWERS MOVING IN. HIGHS ON SATURDAY SHOULD BE WARMER BY SEVERAL DEGREES. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... SOME DIFFERENCES IN THE MODELS BRING SOME UNCERTAINTY TO THE LONG TERM PERIOD. THERE IS A SHORTWAVE RIDING UP ALONG THE EASTERN SEA BOARD FRIDAY INTO SATURDAY. THERE IS SOME DIVERGENCE ON EXACT TIMING/PROPAGATION OF THE SURFACE LOW AND SHORTWAVE. RIGHT NOW WILL STAY WITH SOME CONSISTENCY WITH PREVIOUS FORECAST. ALSO ON FRIDAY A UPPER LEVEL LOW WILL DEVELOP ACROSS THE GREAT LAKES. A SURFACE LOW AND BOUNDARY WILL ALSO DEVELOP AND MOVE EAST INTO THE REGION FOR LATER SUNDAY. THIS ACTIVITY WILL CONTINUE THOUGH MONDAY AS FRONT AND LOW CONTINUE TO TRACK EAST. AS UPPER LEVEL LOW AND SURFACE LOW MOVE EAST OF MAINE EXPECT THE REGION TO SEE A BREAK GOING INTO LATER TUESDAY AND WEDNESDAY. && .AVIATION /19Z WEDNESDAY THROUGH MONDAY/... NEAR TERM: EXPECT VFR CONDITIONS TONIGHT AND THURSDAY. ONLY EXCEPTION IS BRIEF MVFR/IFR KFVE THURSDAY MORNING IN PATCHY FOG. SHORT TERM: VFR EXPECTED INTO FRI AT THE NORTHERN TERMINALS WITH CONDITIONS TO POSSIBLY LOWER TO MVFR/IFR IN RAIN/FOG AT THE SOUTHERN TERMINALS. MOSTLY MVFR/IFR FRI NIGHT INTO SAT...ESPECIALLY AT THE SOUTHERN TERMINALS IN AREAS OF RAIN AND FOG. THERE MAY BE SOME IMPROVEMENT SUNDAY TO MVFR TO VFR. MOSTLY VFR FOR SUNDAY WITH PERIODS OF MVFR/IFR POSSIBLE FOR SUNDAY NIGHT INTO MONDAY. && .MARINE... NEAR TERM: FOR WIND WILL BLEND THE NAM12 AND GFS40. FOR SEAS: SOUTHERLY FETCH OFF THE EAST COAST STILL IN PLACE FROM THE GULF OF MAINE SOUTHWARD. WNA IS A LITTLE HIGH WITH WAVES FROM THIS FETCH WITH ACTUAL HEIGHTS CLOSER TO 4 FEET RATHER THAN 5 FEET. WILL USE THE SWAN/NAM TO INITIALIZE GRIDS. WILL KEEP SEAS AROUND 4 FEET/8 SECONDS. SHORT TERM: SEAS WILL LIKELY REMAIN BELOW SCA LEVELS THROUGH THE WEEKEND. THERE WILL BE A SLY SWELL THAT DEVELOPS OVER THE WEEKEND THAT COULD PUSH SEAS CLOSE TO SCA LEVELS AND WILL NEED TO BE WATCHED. THE WNAWAVE GUIDANCE CONTINUES TO BRING THE SEAS TO 6 FT SAT. THIS MAY BE A LITTLE TOO HIGH. VSBY WILL LIKELY BE LOWERED IN AREAS OF FOG FRI AND FRI NIGHT. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...NONE. MARINE...NONE. && $$ NEAR TERM...MIGNONE SHORT TERM...RUNYAN LONG TERM...JORDAN AVIATION...MIGNONE/RUNYAN MARINE...MIGNONE/RUNYAN
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
420 PM EDT WED JUL 24 2013 .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 419 PM EDT WED JUL 24 2013 WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW NW FLOW INTO THE UPPER GREAT LAKES...RESULTING FROM A RIDGE OVER WRN N AMERICA AND A TROF OVER ERN NAMERICA. WEAK REMNANT OF SHORTWAVE THAT WAS OVER CNTRL SASKATCHEWAN 24HRS AGO IS NOW PASSING OVER THE UPPER GREAT LAKES. 12Z KINL SOUNDING SHOWED A CAP AROUND 12.5KFT MSL...AND LATEST SPC ANALYSIS SHOWS MUCAPE ONLY 100-200J/KG. BOTH DO NOT SUPPORT MUCH OF A SHRA POTENTIAL. KMQT RADAR IS OUT OF SERVICE UNTIL LATE THU MORNING/EARLY AFTN WHILE PARTS ARE IN TRANSIT...SO NOT CERTAIN IF THERE HAS BEEN ANY SHRA OVER W OR CNTRL UPPER MI THIS AFTN. HOWEVER... KGRB/KDLH RADARS HAVE INDICATED A FEW RETURNS...SO THERE MIGHT BE A FEW SPRINKLES OR PERHAPS A -SHRA OUT THERE. UPSTREAM...ISOLD/SCT CONVECTION IS NOTED NW AND N OF LAKE SUPERIOR...TYPICAL FOR SUMMERTIME NW FLOW. FARTHER UPSTREAM...A LARGER SCALE TROF EXTENDING FROM WRN HUDSON BAY TO NRN ALBERTA IS DROPPING S. THIS FEATURE WILL BE THE PLAYER IN THE WEATHER HERE THU THRU SAT. WITH LOSS OF DAYTIME HEATING...ANY ONGOING ISOLD SHRA/SPRINKLES WILL DISSIPATE THIS EVENING. HOWEVER...ANOTHER SUBTLE SHORTWAVE IS NOTED OVER SRN MANITOBA...AND IT IS SUPPORTING MUCH OF THE ISOLD/SCT SHRA/TSRA ACTIVITY OVER SE MANITOBA INTO ADJACENT NRN ONTARIO/NRN MN. THIS WAVE COMBINED WITH WAA REGIME COULD HELP MAINTAIN A FEW SHRA/POSSIBLE TSRA THRU THE NIGHTTIME HRS AS IT CONTINUES TO THE SE. SO...WILL INCLUDE SCHC POPS OVER THE W LATE IN THE NIGHT. ON THU...AFOREMENTIONED LARGER SCALE TROF WILL PIVOT SE INTO NRN ONTARIO AND SRN MANITOBA/SRN SASKATCHEWAN. ASSOCIATED BROAD...BUT ORGANIZING SFC LOW WILL REACH VCNTY OF WRN LAKE SUPERIOR LATE IN THE DAY. THERE MAY BE A FEW SHRA/PERHAPS TSRA DURING THE MORNING HRS WITHIN WAA REGIME. OTHERWISE...BUILDING INSTABILITY IN THE AFTN AND APPROACHING HEIGHT FALLS AS LARGER SCALE TROF SWINGS CLOSER WILL LIKELY RESULT IN INCREASING COVERAGE OF SHRA/TSRA DURING THE DAY. WITH NAM/GFS MLCAPE INCREASING TO UPWARDS OF 1000J/KG AND DEEP LAYER SHEAR PROGGED AT 30-40KT...EXPECT SOME STORM ORGANIZATION...LEADING TO THE POSSIBILITY OF A FEW STRONGER STORMS. IF THERE IS SUFFICIENT DAYTIME HEATING TO RAISE CAPE TO THE MODEL VALUES...THEN THERE WILL BE THE POTENTIAL FOR ISOLD SVR STORMS. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 419 PM EDT WED JUL 24 2013 A LINE OF SHOWERS AND THUNDERSTORMS WILL BE MOVING ACROSS THE AREA AT THE START OF THE LONG TERM PERIOD. THIS IS DUE TO A TROUGH DIGGING SOUTHEAST INTO NORTHERN MINNESOTA AND PRODUCING A BROAD/WEAK LOW PRESSURE SYSTEM MOVING THROUGH THE AREA. THE GENERAL TREND OVER THE LAST COUPLE OF DAYS IS FOR THE SHORTWAVE AND LOW TRACK TO BE FARTHER SOUTH...WHICH INFLUENCES THE WEATHER FOR THE WEEKEND. BEFORE THAT...THE SHOWERS AND THUNDERSTORMS WILL BE MOVING EAST ACROSS CENTRAL AND EASTERN UPPER MICHIGAN DURING THE EVENING AND INTO THE OVERNIGHT HOURS. WITH LIMITED INSTABILITY AND LOSS OF DIURNAL HEATING...THINK THE SEVERE POTENTIAL IS MARGINAL EVEN THOUGH 0-6KM SHEAR VALUES ARE IN THE 35-40KT RANGE. AS THE FIRST WAVE OF PRECIPITATION MOVES EAST...THINK THERE WILL BE LINGERING CLOUDS AND A FEW RAIN SHOWERS OVER THE WEST THROUGH THE NIGHT WITH THE BROAD/WEAK LOW MOVING OVER THE WESTERN U.P. SECOND SHORTWAVE WILL ARRIVE ON FRIDAY (WEST MORNING AND EAST AFTERNOON) AND KICK OFF ANOTHER PERIOD OF NUMEROUS SHOWERS. SINCE THE LOW WILL HAVE SHIFTED TOWARDS CENTRAL UPPER MICHIGAN...ANY INSTABILITY (MUCAPE VALUES UNDER 750 J/KG) WILL BE ALIGNED ALONG AND EAST OF THAT LOCATIONS...SO WILL CONFINE THE BEST THUNDER CHANCES THERE. SINCE 0-6KM SHEAR VALUES ARE ONLY 15-20KTS...HEAVY RAIN WOULD BE THE MAIN THREAT. THIS SECOND SHORTWAVE WILL ALSO CAUSE THE TROUGH TO WRAP UP INTO A CLOSED LOW OVER THE UPPER GREAT LAKES ON FRIDAY NIGHT AND REMAIN IN THE AREA INTO SUNDAY MORNING. THIS WILL LEAD TO WEATHER MORE LIKE LATE SEPTEMBER INSTEAD OF LATE JULY. DURING THAT TIME...EMBEDDED WAVES AND INCREASED MOISTURE WILL LEAD TO CLOUDY CONDITIONS...PERIODS OF RAIN (ESPECIALLY OVER THE NORTH HALF)...GUSTY NORTHWEST WINDS (FRIDAY NIGHT INTO SATURDAY EVENING)...AND TEMPERATURES WELL BELOW NORMAL (50S AND LOW 60S SATURDAY). TEMPERATURES ON SATURDAY MAY BE SOMETHING TO KEEP AN EYE ON...SINCE SOME OF THE RAW MODELS ARE INDICATING HIGHS IN THE UPPER 40S OR LOW 50S OVER THE NORTHWEST HALF OF THE U.P. LOOKING AT SOME PAST HIGHS...THE RECORD COLDEST JULY HIGH TEMPERATURES FOR MANY SITES ARE IN THAT RANGE (NWS MQT 51 IN 2004/1992...CMX 49 IN 1992...IRONWOOD 52 IN 2009/1997). MOST LIKELY PERIOD FOR DRIER WEATHER WILL BE SUNDAY AFTERNOON INTO MONDAY AFTERNOON...AS THE UPPER LOW SHIFTS NORTHEAST INTO QUEBEC AND WEAK HIGH PRESSURE SLIDES ACROSS THE AREA. MODELS CONTINUES TO STRUGGLE ON THAT TIMING WITH THE SPEED OF THE UPPER LOW EXITING...WHICH IS USUALLY THE CASE. ONCE THE LOW SHIFTS NORTHEAST...A SERIES OF SHORTWAVES LOOK TO MOVE ACROSS THE UPPER GREAT LAKES MONDAY NIGHT INTO TUESDAY NIGHT. WILL CONTINUE TO MENTION LOW END CHANCE POPS FOR THESE SHORTWAVES MOVING THROUGH. AFTER THE COOL WEEKEND...TEMPERATURES SHOULD REBOUND TO MORE NORMAL VALUES FOR THE FIRST HALF OF NEXT WEEK. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 136 PM EDT WED JUL 24 2013 VFR CONDITIONS SHOULD BE THE RULE THRU THE FCST PERIOD AT KIWD/KCMX/KSAW UNLESS SOME PCPN OCCURS. ISOLD SHRA MAY DEVELOP THIS AFTN BTWN KIWD/KSAW. HOWEVER...THE PROBABILITY OF SHRA AFFECTING EITHER TERMINAL IS MUCH TOO LOW RIGHT NOW TO INCLUDE ANY MENTION OF SHRA. BETTER OPPORTUNITY FOR PCPN SHOULD DEVELOP LATER THU MORNING INTO THE AFTN AS INSTABILITY BUILDS AHEAD OF AN APPROACHING LOW PRES SYSTEM AND COLD FRONT. FOR NOW...INCLUDED VCNTY SHRA AT ALL TERMINALS AS A STARTING POINT. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 419 PM EDT WED JUL 24 2013 WITH HIGH PRES DEPARTING TO THE E AND LOW PRES APPROACHING FROM THE NW...S WINDS WILL BE THE RULE TONIGHT AND THU...THOUGH SPEEDS SHOULD REMAIN UNDER 20KT. IF THERE ARE ANY STRONGER WINDS...THEY WILL OCCUR OVER ERN LAKE SUPERIOR THU AFTN/EVENING. ONCE THE LOW MOVES E OF LAKE SUPERIOR...WINDS WILL SHIFT AROUND TO THE N TO NW FRI. GIVEN THE INCOMING CHILLY AIR MASS FOR THIS TIME OF YEAR...IT LOOKS LIKE THERE WILL BE A PERIOD OF 15-25KT WINDS OVER MAINLY CNTRL LAKE SUPERIOR FRI NIGHT INTO SAT. HOWEVER...IT`S NOT OUT OF THE QUESTION THAT WINDS COULD BE HIGHER DUE TO THE UNSEASONABLY COOL AIR MASS PUSHING OVER THE AREA. WINDS WILL DIMINISH SUN/MON AS HIGH PRES BUILDS INTO THE WRN GREAT LAKES. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...ROLFSON LONG TERM...SRF AVIATION...ROLFSON MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1218 PM CDT WED JUL 24 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 259 AM CDT WED JUL 24 2013 SPRAWLING COOL AND DRY CANADIAN HIGH IN PLACE AT THE SFC TO START OFF THE DAY. UPSTAIRS THOUGH...A WAVY NW FLOW HAS KEPT A STEADY DIET OF MID CLOUDS STREAMING ACROSS THE AREA OVERNIGHT...WHICH HAS KEPT TEMPS FROM FALLING OFF AS MUCH THEY COULD...ESPECIALLY OVER MN. FOR THE REST OF THE SHORT TERM...WE WILL SEE HEIGHTS BUILD SOME TODAY OUT AHEAD OF A STRONG SHORTWAVE MOVING THROUGH THE CANADIAN PRAIRIES TOWARD NRN MN BY THE END OF THE PERIOD. AT THE SFC...THE HIGH WILL SLIP INTO THE GREAT LAKES WHILE A COLD FRONT SLIPS ACROSS NODAK AND INTO NW MN BY THURSDAY MORNING. BIG QUESTION FOR TODAY WAS TO OR NOT TO INCLUDE SOME ISO THUNDER IN THE FORECAST. IF YOU HEAD OFF IN SEARCH OF YOUR FAVORITE CAM...YOU LIKELY HAVE SEEN THAT MOST GENERATE SOME ISOLATED CONVECTION BY THE AFTERNOON SOMEWHERE NEAR THE I-35 CORRIDOR...BUT AFTER TAKING A PEAK AT SOME DETERMINISTIC GUIDANCE TO SUPPORT THE ISO STORMS...DECIDED AGAINST INCLUDING ANYTHING THROUGH THE AFTERNOON IN THE GRIDS. THERE WERE TWO THINGS THAT PUSHED ME TOWARD A DRY FORECAST FOR TODAY. FIRST...THE RAP CONTINUES TO SHOW NO MUCAPE ACROSS THE MPX AREA THIS AFTERNOON...WITH BEST LI/S REMAINING ABOVE ZERO...NOT EXACTLY WHAT YOU WANT TO SEE FOR THUNDERSTORMS. SECOND...EVEN THOUGH THE NAM GENERATES 500-1000 J/KG OF MLCAPE BY THE AFTERNOON...A QUICK LOOK AT SOUNDINGS ACROSS THE AREA SHOWS THAT IT IS A VERY SKINNY CAPE PROFILE AND ONE THAT DOES NOT LOOK PROMISING FOR GENERATING DEEP MOIST CONVECTION. SO AFTER MUCH DEBATE...DECIDED TO JOIN THE GEM AND ECMWF IN GOING DRY FOR TODAY. THIS EVENING/TONIGHT...PRECIP CHANCES DO LOOK AT LEAST MARGINALLY BETTER. THE REASON IS THAT AS THE STRONG SHORTWAVE DROPS SOUTH OUT OF CANADA...WE WILL SEE H85 WINDS...MOISTURE TRANSPORT AND WAA SLOWLY INCREASING DURING THE NIGHT. THOUGH NOT IMPRESSIVE BY ANY MEANS...USUALLY A PRETTY RISKY PROPOSITION TO NOT INCLUDE SOME POPS FOR A NIGHT TIME PERIOD IN THE SUMMER THAT FEATURES AT LEAST WEAK WAA AND MOISTURE TRANSPORT AT THE H85 LEVEL. MOST LIKELY SCENARIO AT THE MOMENT LOOKS TO BE REMNANTS OF CONVECTION THAT DEVELOPS IN NRN MN THIS AFTERNOON DROPPING SE INTO EC MN AND WRN WI OVERNIGHT. FOR NOW HAVE CHANCE POPS ROUGHLY ALONG AND NORTH OF I-94...THOUGH DO NOT HAVE MUCH CONFIDENCE IN HOW STORMS TONIGHT WILL PLAY OUT AT THE MOMENT. FOR TEMPERATURES...925-850 TEMPS INCREASE TO BETWEEN 16C AND 20C OUT IN WRN MN THIS AFTERNOON...WHICH WILL SUPPORT TEMPERATURES WARMING INTO THE LOW-MID 80S IF CLOUD COVER DOES NOT SLOW THINGS DOWN TOO MUCH. AS A RESULT...DID NUDGE HIGHS UP A COUPLE OF DEGREES OUT WEST...BUT WILL HAVE TO SEE HOW CLOUDS PLAY OUT. TONIGHT...WEAK SRLY FLOW AND WAA SHOULD KEEP TEMPS SIMILAR TO WHAT WE ARE SEEING UNDER THE CLOUDS IN MN TONIGHT...AND ABOUT 5 DEGS WARMER THAN WHAT WE ARE SEEING OVER IN WI RIGHT NOW. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 259 AM CDT WED JUL 24 2013 MAIN ISSUE IN THE LONG TERM IS THUNDERSTORMS AND POTENTIAL FOR SEVERE WX THU AFTN AND EVE...THEN THE MUCH COOLER TEMPERATURES EXPECTED FOR THE WEEKEND. AN UPPER LEVEL LOW CENTER WILL DROP OUT OF MANITOBA THU MRNG SWWD ON ITS WAY INTO THE GRT LAKES. AT THE SFC...A POTENT CDFNT WILL BE LINKED BY TWO ANCHOR LOW PRES CENTERS...ONCE JUST N OF KINL AND THE OTHER OVER SW SD BY MIDDAY WED. THESE TWO SFC LOW PRES CENTERS WILL PHASE TOGETHER OVER THE GRT LAKES BY MIDDAY FRI...SHOVING THE CDFNT THRU THE REGION FRI MRNG WHILE THE UPPER LEVEL LOW DEEPENS INTO A POTENT COMPACT LONGWAVE TROUGH OVER THE UPPER MISSISSIPPI RIVER VALLEY. EFFICIENT WARM SECTORING AHEAD OF THE CDFNT WILL DRAG WARM AND MORE MOIST AIR FROM THE DEEP S UP INTO THE REGION FOR MID-TO-LATE THU. STRONG JETTING IN THE MID- AND UPPER-LEVELS WILL ENHANCE TSTM DEVELOPMENT DURG THE DAY ON THU. OF NOTE HOWEVER IS COLD AIR ALOFT...A FUNCTION OF THE UPPER LOW DROPPING S. THIS WILL ALLOW GROWING STORMS TO HIT THE FREEZING LEVEL QUICKLY... WORKING WITH STEEP LAPSE RATES TO MAKE LARGE HAIL A SEVERE WX HAZARD. IN ADDITION...HELICITIES INCRS SIGNIFICANTLY INVOF THE FNT WITH SWLY WINDS AT THE SFC AND NW FLOW ALOFT DUE TO LOCATION OF THE UPPER LOW. ISOLD TORNADOES...PARTICULARLY OVER SRN MN...ARE ANOTHER POTENTIAL SEVERE WX HAZARD. THE SPC HAS ADDED A SLGT RISK FOR SRN-ERN MN INTO WRN WI IN THE MORNING SWODY2 AND THIS IS WELL WARRANTED. THE CDFNT WILL SHIFT WELL INTO THE GRT LAKES BY FRI EVE...ALLOWING DEEP N-NW FLOW CAA TO COMMENCE. THE UPPER LOW WILL THE SIT-AND- SPIN OVER THE GRT LAKES THRU SUN...KEEPING TEMPERATURES 10-12 DEGREES BELOW NORMAL FRO THRU THE WEEKEND. H85 TEMPS DROP TO ABOUT 6-8 DEG C...WHICH WILL TRANSLATE TO LOWS ARND 50 AND HIGHS ARND 70 FRI THRU SUN. THE DENSE SFC HIGH PRES ASSOCIATED WITH THIS COOLDOWN WILL SHIFT TO THE E DURING THE EARLY PORTION OF NEXT WEEK...ALLOWING FOR A WARMER RETURN FLOW ON THE BACKSIDE OF THE HIGH. TEMPS WILL RISE BACK CLOSER TO NORMAL LEVELS WHILE SEVERAL SHORTWAVE DISTURBANCES RIDE WITHIN THE FLOW BETWEEN A RIDGE OVER THE PLAINS AND A TROUGH OVER THE APPALACHIANS. THESE DISTURBANCES MAY BE ABLE TO SQUEEZE ENOUGH LIMITED MOISTURE TO PRODUCE ISOLD TO SCATTERED SHOWERS AND TSTMS MON-TUE. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1205 PM CDT WED JUL 24 2013 WEAK SFC TROUGH ACROSS EC MN THIS AFTN AND THE ADDED DAYTIME HEATING WEST OF THE PERSISTENT LOWER CLOUD DECK THIS MORNING...WILL LEAD TO SOME INSTABILITY SHRA ACROSS EC MN. LACK OF SUFFICIENT LIFT AND ONLY MODEST INSTABILITY...VCSH IS THE BEST SCENARIO. OTHERWISE...VFR CONDS WILL CONTINUE THRU THIS AFTN/EVENING...WITH A SMALL CHC OF -SHRA/TSRA AFT MIDNIGHT ACROSS EC MN/WC WI WHERE BETTER MOISTURE ADVECTION AND LIFT WILL RESIDE. WINDS WILL BE GENERALLY FROM THE W/NW ACROSS THE WESTERN CWA...WITH A LIGHT SW/W WIND IN THE EASTERN HALF. TIMING OF THE SHRA/TSRA TOMORROW WILL BE DETERMINED BY AFTN SFC HEATING AND WHERE THE COLD FRONT LIES ONCE THE CAP BREAKS. KMSP... AFTN INSTABILITY SHRA ARE POSSIBLE...BUT CIGS WILL REMAIN AOA 5K. WINDS WILL BE GENERALLY FROM THE WSW BLW 7 KTS THRU 00Z...WITH A LIGHT AND VARIABLE WIND...BECOMING SW THURSDAY MORNING. FRONTAL PASSAGE WILL BE SOMETIME BETWEEN 18-22Z/25. SHRA/TSRA WILL LIKELY BE ALONG AND BEHIND THIS FRONT...SO HAVE INTRODUCED PROB30 TSRA BETWEEN 20-24Z. /OUTLOOK FOR KMSP/ THU...LINGERING SHRA/TSRA THURSDAY EVENING. MVFR OR LOWER CONDS POSSIBLE IN TSRA. WINDS SW 5-10 KT...BECOMING NW 10 KTS. FRI...VFR. WINDS NW 10G20 KT. -SHRA IN THE AFTN. SAT...VFR. WINDS NW 5-10 KT. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...MPG LONG TERM...JPC AVIATION...JLT
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
1112 AM MDT WED JUL 24 2013 .UPDATE... BASED ON MOST RECENT HIGH RESOLUTION MODEL RUNS THE FLASH FLOOD WATCH HAS BEEN EXTENDED GEOGRAPHICALLY TO INCLUDE UNION...HARDING...EASTERN SAN MIGUEL AND GUADALUPE COUNTIES. AS A ENERGETIC UPPER LEVEL SHORTWAVE TROUGH AXIS MOVES ACROSS THE FORECAST AREA OVERNIGHT THROUGH TOMORROW MORNING THE THREAT FOR HEAVY RAINFALL HAS EXPANDED TO INCLUDE THE ADDITIONAL COUNTIES MENTIONED IN NORTHEAST NEW MEXICO. SIMILARLY... THE HEAVY RAINFALL THREAT WILL CONTINUE ACROSS THE ORIGINAL WATCH AREA THROUGH TOMORROW MORNING AS WELL. ACCORDINGLY...THE ZONE FORECAST PACKAGE HAS BEEN UPDATED. && .PREV DISCUSSION...606 AM MDT WED JUL 24 2013... .AVIATION... 12Z TAF CYCLE MONSOON BURST EXPECTED TODAY AND THURSDAY AS A DEEP MONSOON MOISTURE PLUME TRACKS N AND NE ACROSS THE FORECAST AREA WITH AN EMBEDDED SUBTROPICAL PERTURBATION OR TWO. THE HRRR MODEL PROGS A WAVE OF -SHRA AND EMBEDDED TS TRACKING NORTHWARD ACROSS W AND CENTRAL NM TODAY...REACHING ABQ IN EARLY AFTN AND SAF BY LATE AFTN. AN UPPER TROUGH IS EXPECTED TO BRUSH NORTHERN PARTS OF THE STATE AS IT TRACKS E ACROSS CO TONIGHT. THIS SHOULD INVIGORATE TS ALONG THE CENTRAL MT CHAIN THIS EVENING AND SEND A CLUSTER OR LINE OF STORMS E ACROSS THE E CENTRAL AND NE PLAINS OVERNIGHT. MEANWHILE...ECMWF AND GFS SUGGEST A SLOW MOVING SUBTROPICAL PERTURBATION COULD LINGER OVER CENTRAL PARTS OF THE STATE TONIGHT KEEPING SHOWERS AND POSSIBLY AN AREA OF STRATIFORM RAIN ACTIVE. STRONGER STORMS TODAY THRU THURSDAY WILL BE CAPABLE OF PRODUCING WET MICROBURSTS WITH VERY HEAVY RAIN AND BRIEF PERIODS OF IFR CONDITIONS WITH MT OBSCURATIONS...ERRATIC WIND GUSTS OVER 45 KT AND FREQUENT/DANGEROUS LIGHTNING. 44 .PREV DISCUSSION...308 AM MDT WED JUL 24 2013... THE AXIS OF MOIST INSTABILITY IS CENTERED SMACK DAB OVER NM THIS MORNING. LATEST WATER VAPOR LOOP SHOWS THE MONSOON PLUME FROM SOUTH TO NORTH WITH A PERTURBATION WASHING OUT ACROSS SOUTHERN NM. PWAT VALUES ARE IMPRESSIVE PER CIRA IMAGERY AND REGIONAL SOUNDINGS. THE GEFS AND SREF SOLUTIONS INDICATE THE 594DM H5 HIGH WILL SHIFT EAST INTO WEST TX TODAY AND ALLOW A RATHER WELL DEFINED PERTURBATION TO SLIDE NORTH INTO CENTRAL NM. PWAT VALUES ARE PROGGED TO AVERAGE THE 1.2-1.4 RANGE ALONG AND SOUTH OF I-40 BY THIS EVENING...WHICH IS WELL WITHIN FLASH FLOOD TERRITORY. DEEP MOIST SSE ATMOSPHERIC FLOW ALONG WITH A WEAK BOUNDARY SHIFTING SW OVER THE EASTERN PLAINS WILL SET THE STAGE FOR SOME TRAINING CELLS. A GLIMPSE OF THE 05Z HRRR SOLUTION SHOWS WIDESPREAD STORMS DEVELOPING FROM SOUTH TO NORTH TODAY. WILL HOIST A FLASH FLOOD WATCH FOR POTENTIAL RAIN RATES NEAR 2 INCHES PER HOUR. STORM MOTIONS WILL AVERAGE ABOUT 15-20 KNOTS HOWEVER CELL TRAINING MAY LEAD TO FLASH FLOODING...ESPECIALLY OVER BURN SCARS. BY THURSDAY THE UPPER HIGH REDEVELOPS OVER ARIZONA WITH LIGHT TO MODERATE NW FLOW DEVELOPING ALOFT OVER NM. THIS WILL SHIFT THE THETA-E RIDGE AXIS IN A SW-NE ORIENTATION...ALLOWING FOR MORE WIDESPREAD ACTIVITY TO SLIDE INTO THE EASTERN PLAINS DURING THE LATE AFTERNOON AND EVENING HOURS. ANOTHER FRONTAL BOUNDARY WILL SHIFT DOWN THE PLAINS THURSDAY NIGHT AND FRIDAY FOCUSING MORE HEAVY RAINFALL ALONG AND EAST OF THE CENTRAL MT CHAIN. PWAT VALUES ARE PROGGED TO FALL BELOW 1.2 FOR MOST OF THE AREA SO FLASH FLOOD THREAT MAY NOT BE AS HIGH...BUT WILL REVISIT AGAIN LATER TODAY. THE FRIDAY/SATURDAY PERIOD WILL FEATURE MOISTURE RECYCLING OVER WESTERN NM AS THE H5 HIGH SHIFTS BACK OVER CENTRAL/EASTERN NM. STORM MOTIONS WILL BECOME VERY WEAK WITH LOCALLY HEAVY RAINFALL OVER SMALLER FOOTPRINTS. POTENTIAL IS INCREASING THAT AN EXTENDED TRUE MONSOONAL BURST PATTERN WILL SET UP BY EARLY NEXT WEEK AS THE 700-500MB HIGH CENTROID SHIFTS INTO TX. THIS WILL OPEN THE DOOR TO DEEP SUBTROPICAL AND MORE HEAVY RAINFALL OVER NM. CLIMATOLOGICALLY WE ARE NOW IN THE MOST FLASHY PERIOD OF THE MONSOON SO WILL JUST CONTINUE TO TREND POPS UP INTO THE EXTENDED AS MODEL CONSISTENCY CONTINUES. GUYER .FIRE WEATHER... A WAVE OF SUBTROPICAL ORIGIN THAT HAS BEEN STATIONARY IN THE VICINITY OF EL PASO AND THE NM BOOTHEEL THE PAST COUPLE DAYS WILL FINALLY SHIFT NORTHWARD INTO CENTRAL PORTIONS OF THE FORECAST AREA TODAY AS THE 500 MB HIGH PRESSURE CENTER REPOSITIONS OVER THE TX PANHANDLE. AN UPPER TROUGH TRACKING SOUTHEASTWARD FROM THE CENTRAL ROCKIES ONTO THE CENTRAL AND SOUTHERN GREAT PLAINS TONIGHT AND THURSDAY WILL THEN SHIFT THE DIRECTION OF THE WAVE...MOVING IT EASTWARD ACROSS THE EAST CENTRAL PLAINS. ALSO...A NORTHEASTERLY WIND SHIFT THAT DEVELOPED ACROSS NE NM TUESDAY AS THE UPPER HIGH BEGAN MIGRATING TOWARD THE TX PANHANDLE FROM UT WILL PUSH THROUGH CENTRAL PARTS OF THE STATE TODAY WITH A MODESTLY GUSTY EAST CANYON WIND AND INCREASED MOISTURE. THE NET RESULT WILL BE INCREASING COVERAGE OF THUNDERSTORMS WITH HEAVY RAIN ACROSS WESTERN...CENTRAL AND NE AREAS TODAY...TONIGHT AND THURSDAY. THOUGH THUNDERSTORMS WILL LIKELY BE SPOTTIER ACROSS SE AREAS...THE STORMS THAT DO DEVELOP WILL CERTAINLY BE CAPABLE OF PRODUCING HEAVY RAINFALL. THE WETTEST PERIOD OF THIS MONSOON BURST WILL LIKELY BE TONIGHT WHEN PRECIPITABLE WATER VALUES ARE FORECAST TO VARY FROM 1 TO 1.5 INCHES ACROSS THE AREA. IN THE WAKE OF THE UPPER TROUGH CLIPPING NE NM FROM THE NW...PRECIPITABLE WATER VALUES SHOULD DROP TO AROUND THREE QUARTERS OF AN INCH ACROSS N CENTRAL AND NW AREAS THURSDAY...WHILE REMAINING RELATIVELY HIGH ELSEWHERE. TEMPERATURES TODAY AND THURSDAY WILL VARY FROM NEAR NORMAL TO AS MUCH AS 6 DEGREES BELOW NORMAL. BY FRIDAY A WEAK UPPER HIGH WILL REFORM VAGUELY OVER AZ AND NM AS THE UPPER TROUGH EXITING THE CENTRAL ROCKIES DIVES SOUTHEASTWARD INTO THE SOUTHERN GREAT PLAINS. HOWEVER...THE MONSOON MOISTURE PLUME WILL REMAIN TRAPPED UNDER THE RIDGE ALOFT AND SQUARELY OVER NM FRIDAY THROUGH THE WEEKEND. THE UPPER TROUGH WILL SEND A SECOND BACK DOOR COLD FRONT INTO THE EAST THURSDAY NIGHT AND FRIDAY. CURRENT THINKING IS THAT THIS FRONT COULD STABILIZE THINGS A BIT ACROSS THE NORTHEAST ON FRIDAY...BUT IT COULD HELP TRIGGER CONVECTION IN CENTRAL AREAS AND POSSIBLY ALSO WESTERN AREAS IF IT MAKES IT THAT FAR. THUS...THE WET WEATHER THAT BEGINS WEDNESDAY SHOULD CONTINUE FRIDAY THROUGH THE WEEKEND...ESPECIALLY CENTRAL AND WEST...THOUGH STORMS WILL SHIFT THEIR DIRECTION OF MOTION AS THE UPPER HIGH CENTER WOBBLES AROUND THE FORECAST AREA. HIGH TEMPERATURES THROUGH THE WEEKEND SHOULD REMAIN A LITTLE COOLER THAN NORMAL. GFS AND ECMWF NOW DEPICT THE 500 MB RIDGE DECREASING IN AMPLITUDE AND STRETCHING FROM CENTRAL NM TO W TX AS A STRONG OF TROUGHS IN THE WESTERLIES CROSS THE CENTRAL ROCKIES. INTERESTINGLY...MODELS KEEP THE MONSOON MOISTURE PLUME OVER THE FORECAST AREA...THOUGH IT MAY TILT FROM THE SW TO NE QUADRANTS. THUS...DAILY ROUNDS OF SCATTERED TO ISOLATED AND AT TIMES NUMEROUS STORMS WILL CONTINUE. SPOTTIER CONVECTION MAY BE FOUND ACROSS NW AREAS WHERE SOME DRIER AIR COULD ARRIVE IN THE WAKE OF SOME OF THE UPPER TROUGHS. TEMPERATURES SHOULD REMAIN NEAR AND A LITTLE BELOW NORMAL. 44 && .ABQ WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH THROUGH THURSDAY MORNING FOR THE FOLLOWING ZONES...NMZ501>533-539-540. && $$ 01
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
413 PM EDT WED JUL 24 2013 .SYNOPSIS... HIGH PRESSURE WILL BUILD EASTWARD INTO THE REGION TONIGHT INTO THURSDAY WITH DRY AND SEASONABLY COOL WEATHER EXPECTED. A SERIES OF LOW PRESSURE SYSTEMS PASSING ALONG THE NEW ENGLAND COAST MAY SPREAD A SOME CLOUDS AND AN OUTSIDE CHANCE OF A FEW SHOWERS TO FAR EASTERN AREAS FRIDAY...BUT MAINLY DRY WEATHER AND SLIGHTLY WARMER TEMPERATURES ARE EXPECTED FOR MOST OF THE AREA. AN UNSETTLED PATTERN THEN DEVELOPS ACROSS NORTHERN NEW YORK ON SATURDAY...AND ACROSS THE ENTIRE REGION BY SUNDAY INTO MONDAY AS ADDITIONAL FRONTAL ENERGY PROGRESSES EAST FROM THE GREAT LAKES STATES. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... AS OF 345 PM EDT WEDNESDAY...QUIET NIGHT TONIGHT AS COOL CANADIAN HIGH PRESSURE SLOWLY BUILDS INTO THE REGION. WITH LOSS OF INSOLATION...STRATOCUMULUS CLOUD FIELD SHOULD SLOWLY DISSIPATE OVER TIME AND OUTSIDE SOME HIGH CLOUD COVER POSSIBLE EAST MOSTLY CLEAR CONDITIONS ARE EXPECTED ACROSS OUR AREA LATER TONIGHT. LOWS CLOSE TO BLENDED MOS VALUES (40S TO AROUND 50) THOUGH WITH CUSTOMARY VARIABILITY...ESPECIALLY ALONG LAKE CHAMPLAIN WHERE WATER TEMPERATURES REMAIN AROUND 70F. PATCHY FOG ALSO POSSIBLE HERE AND THERE...BUT MOST FAVORABLE ACROSS NORTHERN NEW YORK WHERE WINDS ATOP THE NOCTURNAL BOUNDARY LAYER WILL BE THE LIGHTEST. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/... AS OF 345 PM EDT WEDNESDAY...MAINLY NICE WEATHER THEN CONTINUES FOR THE REMAINDER OF THE SHORT TERM AS AFOREMENTIONED HIGH PRESSURE BUILDS ACROSS OUR AREA. THE SURFACE FRONT THAT CROSSED OUR AREA THIS MORNING WILL STALL ALONG OR JUST OFFSHORE THE NEW ENGLAND COAST DURING THIS PERIOD...AND THERE WILL BE A SERIES OF LOW PRESSURE WAVES THAT WILL RIDE NORTHEAST ALONG THE BOUNDARY. HOWEVER...OUTSIDE THE WESTERN OUTLIER SOLUTION OF THIS MORNING`S NAM...GLOBAL MODELS REMAIN FAIRLY CONSISTENT IN SHOWING DEEPER MOISTURE AND THREAT OF RAINFALL REMAINING GENERALLY EAST OF OUR AREA. THUS I`LL CONTINUE TO LEAN IN THIS DIRECTION SUGGESTING MAINLY DRY WEATHER AND ONLY SOME CLOUDS AND PERHAPS AN OUTSIDE SHOT AT A SHOWER OR TWO ACROSS OUR FAR EASTERN COUNTIES BY FRIDAY. HIGHS SLOWLY MODERATE INTO THE 70S BY TOMORROW...AND 75 TO 82 BY FRIDAY WITH COOLEST READINGS EAST WITH HIGHER DEGREE OF CLOUD COVER. LOWS IN THE 40S TO LOWER 50S THURSDAY NIGHT...THEN MILDER IN THE 50S TO AROUND 60 BY FRIDAY NIGHT AS FLOW TRENDS LIGHT SOUTHERLY. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... AS OF 410 PM EDT WEDNESDAY...LITTLE CHANGE IN OVERALL THINKING FOR PERIODS 4 THRU 7...WITH FCST FOCUS ON TIMING OF PRECIP SUNDAY INTO MONDAY. MODELS IN GOOD AGREEMENT WITH LARGE SCALE SYNOPTIC FEATURES...BUT STILL HAVING TIMING ISSUES ASSOCIATED WITH FRONT AND RIBBON OF ENHANCED RH ON SUNDAY. LATEST TRENDS HAVE BEEN FOR A DEEPER/MORE AMPLIFIED SYSTEM ACRS THE CENTRAL GREAT LAKES AND FRNT/RH PARALLELING THE MID/UPPER LVL FLOW. THIS DEEPLY CLOSED 5H/7H CIRCULATION AND BOUNDARY PARALLELING THE FLW ALOFT WOULD RESULT IN A SLOWER ARRIVAL TIME OF PRECIP ON SUNDAY. WL MENTION CHC POPS IN THE MORNING...THEN LIKELY FROM 18Z TO 06Z SUNDAY/MONDAY...BEFORE TAPERING BACK TO CHC POPS AFT 06Z MONDAY. IN ADDITION...BOTH GFS/ECMWF SHOW POTENT RRQ OF 25H JET LIFTING FROM SOUTH TO NORTH ACRS OUR REGION...AHEAD OF DIGGING TROF...WHICH WL HELP TO ENHANCE ULVL DIVERGENCE AND PROMOTE DEEP LAYER LIFT LATE SUNDAY. OTHERWISE...MID/UPPER LVL TROF PREVAILS ACRS THE NE CONUS FOR EARLY NEXT WEEK...WITH WEAK EMBEDDED VORTS. STILL SOME UNCERTAINTY ON DEEP OF AVAILABLE MOISTURE AND TIMING OF INDIVIDUAL S/W`S...SOME HAVE MENTIONED SCHC/LOW CHC POPS THRU EARLY NEXT WK. PROGGED 85H TEMPS AHEAD OF BOUNDARY WARM BTWN 12-14C OVER THE WEEKEND...SUPPORTING HIGHS IN THE M70S MTNS TO L/M 80S WARMER VALLEYS. HOWEVER...AS TROF MOVES OVERHEAD THERMAL PROFILES COOL AND TEMPS WL DROP BACK MAINLY IN THE 70S...OVERALL VERY CLOSE TO NORMAL. && .AVIATION /20Z WEDNESDAY THROUGH MONDAY/... THROUGH 18Z THURSDAY...AVIATION CHALLENGE WL BE DISSIPATION OF STRATO CUMULUS DECK LATE THIS AFTN/EVENING...FOLLOWED BY FOG/BR POTENTIAL. CRNT VIS SATL PIC SHOWS LOTS OF STRATO CU ACRS OUR TAF SITES...ASSOCIATED WITH NW UPSLOPE FLW AND LLVL CAA. SOME UNCERTAINTY TO WHEN THIS DISSIPATES...AS RAP SHOWS LLVL MOISTURE HANGING AROUND THRU 04Z...ESPECIALLY AT MPV/SLK...WHILE GFS/NAM SHOW RAPID DECREASE IN RH BTWN 18Z-21Z TODAY. WL USE COMPROMISE AND SHOW MVFR CIGS IMPROVING TO VFR AT ALL TAF SITES BY EARLY THIS EVENING. IN ADDITION...AS LLVL`S STABILIZE FROM LACK OF SFC HEATING...EXPECT WINDS TO DECREASE AT 4 TO 8 KNTS. SOUNDINGS SHOW BL WINDS BTWN 6 AND 12 KNOTS TONIGHT...AS SFC HIGH PRES IS ACRS THE CENTRAL GREAT LAKES...ALONG WITH SOME LEFTOVER CLOUDS...ESPECIALLY ACRS THE UPSLOPE TAF SITES OF MPV/SLK. THIS MOISTURE AND WIND...MAY PREVENT WIDESPREAD FOG/BR FROM DEVELOPING. HAVE MENTION TEMPO GROUP AT MSS/SLK BTWN 07Z-11Z. OTHERWISE...VFR WL PREVAIL BTWN 12-18Z THURS. OUTLOOK 18Z THURSDAY THROUGH SUNDAY... MAINLY VFR CONDITIONS WL PREVAIL THRU SUNDAY...AS WEAK SFC LOW PRES TRACKS TWD CAPE COD ON FRIDAY...BUT BEST MOISTURE WL STILL EAST OF OUR FA. ANOTHER SYSTEM ON SUNDAY WL PRODUCE SCATTERED SHOWERS WITH A CHANCE OF THUNDER ACRS OUR CWA. EXPECT MAINLY VFR BUT A BRIEF PERIOD OF MVFR IN THE STRONGER STORMS WL BE POSSIBLE...ESPECIALLY SUNDAY AFTN. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...NONE. NY...NONE. && $$ SYNOPSIS...JMG NEAR TERM...JMG SHORT TERM...JMG LONG TERM...TABER AVIATION...TABER
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
345 PM EDT WED JUL 24 2013 .SYNOPSIS... HIGH PRESSURE WILL BUILD EASTWARD INTO THE REGION TONIGHT INTO THURSDAY WITH DRY AND SEASONABLY COOL WEATHER EXPECTED. A SERIES OF LOW PRESSURE SYSTEMS PASSING ALONG THE NEW ENGLAND COAST MAY SPREAD A SOME CLOUDS AND AN OUTSIDE CHANCE OF A FEW SHOWERS TO FAR EASTERN AREAS FRIDAY...BUT MAINLY DRY WEATHER AND SLIGHTLY WARMER TEMPERATURES ARE EXPECTED FOR MOST OF THE AREA. AN UNSETTLED PATTERN THEN DEVELOPS ACROSS NORTHERN NEW YORK ON SATURDAY...AND ACROSS THE ENTIRE REGION BY SUNDAY INTO MONDAY AS ADDITIONAL FRONTAL ENERGY PROGRESSES EAST FROM THE GREAT LAKES STATES. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... AS OF 345 PM EDT WEDNESDAY...QUIET NIGHT TONIGHT AS COOL CANADIAN HIGH PRESSURE SLOWLY BUILDS INTO THE REGION. WITH LOSS OF INSOLATION...STRATOCUMULUS CLOUD FIELD SHOULD SLOWLY DISSIPATE OVER TIME AND OUTSIDE SOME HIGH CLOUD COVER POSSIBLE EAST MOSTLY CLEAR CONDITIONS ARE EXPECTED ACROSS OUR AREA LATER TONIGHT. LOWS CLOSE TO BLENDED MOS VALUES (40S TO AROUND 50) THOUGH WITH CUSTOMARY VARIABILITY...ESPECIALLY ALONG LAKE CHAMPLAIN WHERE WATER TEMPERATURES REMAIN AROUND 70F. PATCHY FOG ALSO POSSIBLE HERE AND THERE...BUT MOST FAVORABLE ACROSS NORTHERN NEW YORK WHERE WINDS ATOP THE NOCTURNAL BOUNDARY LAYER WILL BE THE LIGHTEST. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/... AS OF 345 PM EDT WEDNESDAY...MAINLY NICE WEATHER THEN CONTINUES FOR THE REMAINDER OF THE SHORT TERM AS AFOREMENTIONED HIGH PRESSURE BUILDS ACROSS OUR AREA. THE SURFACE FRONT THAT CROSSED OUR AREA THIS MORNING WILL STALL ALONG OR JUST OFFSHORE THE NEW ENGLAND COAST DURING THIS PERIOD...AND THERE WILL BE A SERIES OF LOW PRESSURE WAVES THAT WILL RIDE NORTHEAST ALONG THE BOUNDARY. HOWEVER...OUTSIDE THE WESTERN OUTLIER SOLUTION OF THIS MORNING`S NAM...GLOBAL MODELS REMAIN FAIRLY CONSISTENT IN SHOWING DEEPER MOISTURE AND THREAT OF RAINFALL REMAINING GENERALLY EAST OF OUR AREA. THUS I`LL CONTINUE TO LEAN IN THIS DIRECTION SUGGESTING MAINLY DRY WEATHER AND ONLY SOME CLOUDS AND PERHAPS AN OUTSIDE SHOT AT A SHOWER OR TWO ACROSS OUR FAR EASTERN COUNTIES BY FRIDAY. HIGHS SLOWLY MODERATE INTO THE 70S BY TOMORROW...AND 75 TO 82 BY FRIDAY WITH COOLEST READINGS EAST WITH HIGHER DEGREE OF CLOUD COVER. LOWS IN THE 40S TO LOWER 50S THURSDAY NIGHT...THEN MILDER IN THE 50S TO AROUND 60 BY FRIDAY NIGHT AS FLOW TRENDS LIGHT SOUTHERLY. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... AS OF 408 AM EDT WEDNESDAY...GOING INTO THE WEEKEND MEDIUM RANGE GUIDANCE REMAINS FAIRLY CONSISTENT WITH THE MAIN WEATHER FEATURE CONTINUING TO BE A CLOSED 500MB TROUGH AND ASSOCIATED SURFACE COLD FRONT DIGGING SOUTHWARD INTO GREAT LAKES SATURDAY...AND THEN PROGRESSING EASTWARD THROUGH THE NORTHEAST ON SUNDAY. SOUTHWEST FLOW AHEAD OF THIS FEATURE SHOULD KEEP THE BTV CWA DRY FOR SATURDAY...THOUGH SEVERAL MODELS ARE NOW HINTING AT SOME SORT OF COASTAL LOW MOVING NORTHWARD FROM THE CAROLINA COAST FRIDAY AFTERNOON TO THE GULF OF MAIN BY SATURDAY AFTERNOON. FEEL SINCE THE FLOW AROUND THIS FEATURE IS FAIRLY WEAK WRAP AROUND MOISTURE SHOULD STAY EAST OF THE AREA...BUT CERTAINLY SOMETHING TO KEEP AN EYE ON. FOR SUNDAY...COLD FRONT PUSHES THROUGH THE REGION WITH INCREASING CONFIDENCE THAT WE`LL SEE A GOOD 6-HOUR PERIOD OF RAIN WITH SOME MODEST QPF SUNDAY MORNING...TAPERING OFF IN THE AFTERNOON AND EVENING HOURS. FROM SUNDAY ONWARD LONGER RANGE GUIDANCE OF THE GFS AND ECMWF DIFFER QUITE A BIT IN REGARDS TO THE STRENGTH AND MOVEMENT OF THE AFOREMENTIONED UPPER LOW/TROUGH. THE GFS OFFERS A DEEPER/SLOWER CLOSED UPPER LOW LINGERING OVER THE INTL BORDER THROUGH TUESDAY...WHILE THE ECMWF IS MUCH MORE PROGRESSIVE PUSHING THE SYSTEM NORTH AND EAST OF THE AREA. GFS ENSEMBLE GUIDANCE IS MORE IN LINE WITH THE ECMWF...SO HAVE LEANED TOWARDS THE FASTER/DRIER SOLUTION FOR MONDAY ONWARDS. TEMPS THROUGH THE PERIOD REMAIN VERY SEASONAL WITH HIGHS GENERALLY IN THE MID 70S TO LOWER 80S...AND LOWS IN THE MID 50S TO MID 60S. && .AVIATION /20Z WEDNESDAY THROUGH MONDAY/... THROUGH 18Z THURSDAY...AVIATION CHALLENGE WL BE DISSIPATION OF STRATO CUMULUS DECK LATE THIS AFTN/EVENING...FOLLOWED BY FOG/BR POTENTIAL. CRNT VIS SATL PIC SHOWS LOTS OF STRATO CU ACRS OUR TAF SITES...ASSOCIATED WITH NW UPSLOPE FLW AND LLVL CAA. SOME UNCERTAINTY TO WHEN THIS DISSIPATES...AS RAP SHOWS LLVL MOISTURE HANGING AROUND THRU 04Z...ESPECIALLY AT MPV/SLK...WHILE GFS/NAM SHOW RAPID DECREASE IN RH BTWN 18Z-21Z TODAY. WL USE COMPROMISE AND SHOW MVFR CIGS IMPROVING TO VFR AT ALL TAF SITES BY EARLY THIS EVENING. IN ADDITION...AS LLVL`S STABILIZE FROM LACK OF SFC HEATING...EXPECT WINDS TO DECREASE AT 4 TO 8 KNTS. SOUNDINGS SHOW BL WINDS BTWN 6 AND 12 KNOTS TONIGHT...AS SFC HIGH PRES IS ACRS THE CENTRAL GREAT LAKES...ALONG WITH SOME LEFTOVER CLOUDS...ESPECIALLY ACRS THE UPSLOPE TAF SITES OF MPV/SLK. THIS MOISTURE AND WIND...MAY PREVENT WIDESPREAD FOG/BR FROM DEVELOPING. HAVE MENTION TEMPO GROUP AT MSS/SLK BTWN 07Z-11Z. OTHERWISE...VFR WL PREVAIL BTWN 12-18Z THURS. OUTLOOK 18Z THURSDAY THROUGH SUNDAY... MAINLY VFR CONDITIONS WL PREVAIL THRU SUNDAY...AS WEAK SFC LOW PRES TRACKS TWD CAPE COD ON FRIDAY...BUT BEST MOISTURE WL STILL EAST OF OUR FA. ANOTHER SYSTEM ON SUNDAY WL PRODUCE SCATTERED SHOWERS WITH A CHANCE OF THUNDER ACRS OUR CWA. EXPECT MAINLY VFR BUT A BRIEF PERIOD OF MVFR IN THE STRONGER STORMS WL BE POSSIBLE...ESPECIALLY SUNDAY AFTN. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...NONE. NY...NONE. && $$ SYNOPSIS...JMG NEAR TERM...JMG SHORT TERM...JMG LONG TERM...LAHIFF AVIATION...TABER
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
129 PM EDT WED JUL 24 2013 .SYNOPSIS... A COLD FRONT WILL PUSH THROUGH VERMONT EARLY TODAY WITH SCATTERED SHOWERS AND POSSIBLY A THUNDERSTORM. BEHIND THIS FRONT...HIGH PRESSURE WILL USHER IN DRY WEATHER AND COOLER TEMPERATURES. HIGH PRESSURE REMAINS OVER THE REGION THURSDAY AND FRIDAY...WITH SEASONABLY MILD AND DRY WEATHER EXPECTED. TEMPERATURES WILL TREND WARMER BY SATURDAY. THE NEXT CHANCE OF SIGNIFICANT RAINFALL WILL OCCUR BY SUNDAY AS ANOTHER COLD FRONT MAKES ITS WAY EASTWARD. && .NEAR TERM /UNTIL 7 PM THIS EVENING/... AS OF 120 PM EDT WEDNESDAY...COLD POST-FRONTAL ADVECTION CONTINUES THIS AFTERNOON UNDER MODERATELY GUSTY NORTHWEST FLOW AND SCATTERED TO BROKEN LOW LEVEL STRATOCUMULUS CLOUDS. BASED OFF CURRENT OBSERVATIONAL DATA OPTED TO LOWER MAX TEMPS A TAD FURTHER...ESPECIALLY ACROSS THE HIGHER ELEVATIONS WHERE HIGHEST DEGREE OF CLOUD COVER WILL EXIST. CURRENTLY 41F ON WHITEFACE SUMMIT WITH A WINDCHILL OF 29F...SO TAKE A JACKET OR OTHER THERMAL WEAR IF PLANNING A HIKE IN THE HIGHER TERRAIN THIS AFTERNOON. REST OF FORECAST IN GREAT SHAPE. && .SHORT TERM /7 PM THIS EVENING THROUGH FRIDAY/... AS OF 408 AM EDT WEDNESDAY...OUTSTANDING STRETCH OF WEATHER EXPECTED FOR THE REMAINDER OF THE SHORT TERM AS CANADIAN HIGH PRESSURE BUILDS EASTWARD INTO THE REGION TONIGHT THROUGH THURSDAY...AND THEN RETREATS INTO EASTERN QUEBEC FRIDAY. DRY WEATHER THROUGH THE PERIOD...WITH MAINLY CLEAR SKIES TONIGHT THROUGH THURSDAY NIGHT...FOLLOWED BY A BIT MORE CLOUDINESS ON FRIDAY. TEMPERATURES WILL BE BELOW NORMAL THURSDAY WITH HIGHS MAINLY IN THE LOWER TO MID 70S. THEY WILL RETURN TO SEASONABLE LEVELS FRIDAY WITH VALLEY HIGHS AROUND 80. LOWS BOTH NIGHTS WILL BE QUITE COOL...IN THE 40S TO AROUND 50. EXCEPTIONS WILL BE IN THE MOUNTAIN VALLEYS WHERE THERE WILL BE SOME 30S...AND ALONG THE LAKE CHAMPLAIN SHORELINE WHERE IT WILL BE MILDER DUE TO THE WARM LAKE TEMPS WHICH ARE CURRENTLY IN THE LOWER 70S. PATCHY FOG ALSO A GOOD BET... ESPECIALLY TONIGHT AS SOIL MOISTURE LEVELS STILL QUITE HIGH. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... AS OF 408 AM EDT WEDNESDAY...GOING INTO THE WEEKEND MEDIUM RANGE GUIDANCE REMAINS FAIRLY CONSISTENT WITH THE MAIN WEATHER FEATURE CONTINUING TO BE A CLOSED 500MB TROUGH AND ASSOCIATED SURFACE COLD FRONT DIGGING SOUTHWARD INTO GREAT LAKES SATURDAY...AND THEN PROGRESSING EASTWARD THROUGH THE NORTHEAST ON SUNDAY. SOUTHWEST FLOW AHEAD OF THIS FEATURE SHOULD KEEP THE BTV CWA DRY FOR SATURDAY...THOUGH SEVERAL MODELS ARE NOW HINTING AT SOME SORT OF COASTAL LOW MOVING NORTHWARD FROM THE CAROLINA COAST FRIDAY AFTERNOON TO THE GULF OF MAIN BY SATURDAY AFTERNOON. FEEL SINCE THE FLOW AROUND THIS FEATURE IS FAIRLY WEAK WRAP AROUND MOISTURE SHOULD STAY EAST OF THE AREA...BUT CERTAINLY SOMETHING TO KEEP AN EYE ON. FOR SUNDAY...COLD FRONT PUSHES THROUGH THE REGION WITH INCREASING CONFIDENCE THAT WE`LL SEE A GOOD 6-HOUR PERIOD OF RAIN WITH SOME MODEST QPF SUNDAY MORNING...TAPERING OFF IN THE AFTERNOON AND EVENING HOURS. FROM SUNDAY ONWARD LONGER RANGE GUIDANCE OF THE GFS AND ECMWF DIFFER QUITE A BIT IN REGARDS TO THE STRENGTH AND MOVEMENT OF THE AFOREMENTIONED UPPER LOW/TROUGH. THE GFS OFFERS A DEEPER/SLOWER CLOSED UPPER LOW LINGERING OVER THE INTL BORDER THROUGH TUESDAY...WHILE THE ECMWF IS MUCH MORE PROGRESSIVE PUSHING THE SYSTEM NORTH AND EAST OF THE AREA. GFS ENSEMBLE GUIDANCE IS MORE IN LINE WITH THE ECMWF...SO HAVE LEANED TOWARDS THE FASTER/DRIER SOLUTION FOR MONDAY ONWARDS. TEMPS THROUGH THE PERIOD REMAIN VERY SEASONAL WITH HIGHS GENERALLY IN THE MID 70S TO LOWER 80S...AND LOWS IN THE MID 50S TO MID 60S. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/... THROUGH 18Z THURSDAY...AVIATION CHALLENGE WL BE DISSIPATION OF STRATO CUMULUS DECK LATE THIS AFTN/EVENING...FOLLOWED BY FOG/BR POTENTIAL. CRNT VIS SATL PIC SHOWS LOTS OF STRATO CU ACRS OUR TAF SITES...ASSOCIATED WITH NW UPSLOPE FLW AND LLVL CAA. SOME UNCERTAINTY TO WHEN THIS DISSIPATES...AS RAP SHOWS LLVL MOISTURE HANGING AROUND THRU 04Z...ESPECIALLY AT MPV/SLK...WHILE GFS/NAM SHOW RAPID DECREASE IN RH BTWN 18Z-21Z TODAY. WL USE COMPROMISE AND SHOW MVFR CIGS IMPROVING TO VFR AT ALL TAF SITES BY EARLY THIS EVENING. IN ADDITION...AS LLVL`S STABILIZE FROM LACK OF SFC HEATING...EXPECT WINDS TO DECREASE AT 4 TO 8 KNTS. SOUNDINGS SHOW BL WINDS BTWN 6 AND 12 KNOTS TONIGHT...AS SFC HIGH PRES IS ACRS THE CENTRAL GREAT LAKES...ALONG WITH SOME LEFTOVER CLOUDS...ESPECIALLY ACRS THE UPSLOPE TAF SITES OF MPV/SLK. THIS MOISTURE AND WIND...MAY PREVENT WIDESPREAD FOG/BR FROM DEVELOPING. HAVE MENTION TEMPO GROUP AT MSS/SLK BTWN 07Z-11Z. OTHERWISE...VFR WL PREVAIL BTWN 12-18Z THURS. OUTLOOK 18Z THURSDAY THROUGH SUNDAY... MAINLY VFR CONDITIONS WL PREVAIL THRU SUNDAY...AS WEAK SFC LOW PRES TRACKS TWD CAPE COD ON FRIDAY...BUT BEST MOISTURE WL STILL EAST OF OUR FA. ANOTHER SYSTEM ON SUNDAY WL PRODUCE SCATTERED SHOWERS WITH A CHANCE OF THUNDER ACRS OUR CWA. EXPECT MAINLY VFR BUT A BRIEF PERIOD OF MVFR IN THE STRONGER STORMS WL BE POSSIBLE...ESPECIALLY SUNDAY AFTN. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...NONE. NY...NONE. && $$ SYNOPSIS...RJS NEAR TERM...JMG SHORT TERM...RJS LONG TERM...LAHIFF AVIATION...TABER
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
305 PM CDT WED JUL 24 2013 .DISCUSSION... A WEAK OUTFLOW BOUNDARY OVER EXTREME NE TEXAS WILL SAG SLOWLY SOUTH THROUGH THIS EVENING. CONVECTION IS DEVELOPING ALONG THE BOUNDARY AND THE RAP AND HRR BRING A FEW SHRA/TSRA INTO THE EXTREME NORTHERN PART OF SE TX. WILL CONTINUE TO ADVERTISE ISOLATED ACTIVITY OVER THE NE ZONES THIS EVENING. A BIT MORE CLOUD COVER TODAY THAN PREVIOUS DAYS AND THIS HAS KEPT TEMPS IN CHECK THIS AFTN. 500 HEIGHTS CONTINUE TO BUILD THURSDAY AND FRIDAY SO THINK THE CURRENT TREND OF WARMER TEMPS IS ON THE MARK. ECMWF LOOKS A LITTLE TOO WARM SO SPLIT THE DIFFERENCE BETWEEN THE ECMWF AND GFS. ONLY SIGNIFICANT CHANGE TO GOING FORECAST WAS TO RAISE RAIN CHANCES FOR SATURDAY. MODELS ARE MORE AGGRESSIVE WITH A DIGGING S/WV ON THE PERIPHERY OF THE UPPER HIGH LOCATED OVER THE INTERMOUNTAIN WEST. PW VALUES WILL INCREASE TO NEAR 2.00 INCHES ON SATURDAY AND JET DYNAMICS LOOK RATHER FAVORABLE WITH SE TX LYING IN A LEFT FRONT QUAD AND UPPER LEVEL WINDS BECOMING DIVERGENT. WILL RAISE POPS TO CHANCE ACROSS ALL OF SE TX FOR SATURDAY. THE UPPER LEVEL RIDGE REASSERTS ITSELF ON SUNDAY AND BEYOND AND RAIN CHANCES WILL BEGIN TO DECLINE. WILL MAINTAIN SLIGHT RAIN CHANCES ON SUNDAY AND THAT LOOKS KINDA GENEROUS CONSIDERING THE STRENGTH OF THE BUILDING RIDGE. UPPER LEVEL RIDGING PARKS OVER WEST TEXAS TUESDAY THROUGH THURSDAY WITH VERY WARM AND DRY CONDITIONS EXPECTED. 43 && .MARINE... LOWER TO MID LEVEL HIGH PRESSURE OVER THE GULF WILL MAINTAIN AN EARLY DAY SOUTHWEST...BACKING SOUTH THROUGH THE DAY...LIGHT TO MODERATE WIND FIELD. THIS FETCH WILL KEEP SEA HEIGHTS IN THE TWO TO THREE FOOT RANGE NEARSHORE...BETWEEN THREE TO FOUR FEET FURTHER OFFSHORE. AN INCREASED CHANCE FOR PRECIPITATION SATURDAY AS AN INLAND BOUNDARY ADVANCES INTO EASTERN TEXAS. 31 && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 75 99 76 100 76 / 10 10 10 10 10 HOUSTON (IAH) 76 97 77 97 77 / 10 10 10 10 10 GALVESTON (GLS) 79 92 80 92 81 / 10 10 10 10 10 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1149 AM CDT WED JUL 24 2013 .AVIATION... PREVAILING VFR CONDITIONS ARE EXPECTED AT BOTH TERMINALS THIS TAF CYCLE... WITH POSSIBLE BRIEF EXCEPTIONS AT LBB AS ISOLATED TO WIDELY SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP IN THE AREA DURING THE AFTERNOON. THE STRONGEST STORMS MAY PRODUCE SMALL HAIL AND WIND GUSTS TO 60 MPH...ALTHOUGH THIS WILL BE THE EXCEPTION AND NOT THE RULE. STORMS SHOULD DIMINISH BY SUNSET... WITH POSSIBLE BRIEF STORM DURING THE OVERNIGHT HOURS. CHANCES OF THE LATTER OCCURRING ARE TOO LOW FOR MENTION IN THIS EDITION OF THE TAF. && .PREV DISCUSSION... /ISSUED 948 AM CDT WED JUL 24 2013/ UPDATE... A FEW TWEAKS TO TODAYS FORECAST TO REFLECT CURRENT TRENDS. THE CONVECTIVE COMPLEX ACROSS NORTH TX APPEARS TO BE REINFORCING THE COLD FRONT...NOW ACROSS THE NORTHERN SOUTH PLAINS AND ROLLING PLAINS. SHORT RANGE MODEL GUIDANCE...INCLUDING THE HRRR...TTUWRF...AND RAP ALL INDICATE THAT THIS FRONT WILL LIKELY REACH AT LEAST THE SOUTHERN PORTION OF THE CWA BY MID AFTERNOON...AND PERHAPS EVEN BEYOND AS SHOWN BY THE AGGRESSIVE ECMWF. AS A RESULT...OPTED TO SHIFT POPS SOUTHWARD TO FAVOR THE SOUTHERN ROLLING PLAINS AND SOUTH PLAINS FOR THIS AFTERNOON. CONVECTION IS EXPECTED TO REMAIN TIED TO THE BOUNDARY TODAY GIVEN SOMEWHAT WARM MID-LEVEL TEMPERATURES AND A LACK OF ANOTHER WELL- DEFINED FORCING MECHANISM...WITH THE EXCEPTION OF THE HIGH TERRAIN OF NEW MEXICO...AND AS A RESULT PORTIONS OF THE NORTHERN ROLLING PLAINS WILL LIKELY REMAIN DRY. FARTHER WEST...MORE ROBUST CONVECTIVE DEVELOPMENT IS EXPECTED ACROSS EASTERN NEW MEXICO WITHIN AN UPSLOPE FLOW REGIME...AND AT LEAST SOME OF THIS ACTIVITY IS EXPECTED TO REACH AT LEAST THE WESTERN SOUTH PLAINS LATE IN THE AFTERNOON AND INTO THE EVENING. GIVEN THE MODERATE INSTABILITY PRESENT... A FEW PULSE-TYPE THUNDERSTORMS MAY BE CAPABLE OF PRODUCING SMALL HAIL AND GUSTY WINDS... ALTHOUGH ANEMIC SHEAR WILL LIKELY PRECLUDE A WIDESPREAD SEVERE THREAT. IN ADDITION... A FEW SHOWERS AND PERHAPS A RUMBLE OF THUNDER OR TWO WILL BE POSSIBLE AS THE GUST FRONT MOVES THROUGH THE SOUTHERN ROLLING PLAINS THIS MORNING THROUGH THE EARLY AFTERNOON AS WELL. PREV DISCUSSION... /ISSUED 634 AM CDT WED JUL 24 2013/ AVIATION... VFR CONDITIONS EXPECTED FOR THE NEXT 24 HOURS. WEAK FRONTAL BOUNDARY WILL SAG SOUTHWARD DURING THE DAY. THERE IS SOME RISK OF TSTMS THIS AFTERNOON AND EVENING /THOUGH FAVORING KCDS/ AT BOTH TERMINALS. PREV DISCUSSION... /ISSUED 319 AM CDT WED JUL 24 2013/ SHORT TERM... FLOW OVER THE CONUS THIS MORNING IS CHARACTERIZED BY LARGE SCALE RIDGING OUT WEST AND TROUGHING ACROSS THE EAST. UPPER LEVEL HIGH HAS EXPANDED OUR WAY A BIT MORE FOR TODAY WHICH WILL HELP TEMPS RISE A FEW DEGREES. POLAR JET IS ORIENTED FROM SK TO TN. THE ASSOCIATED H5 WIND MAX IS EXPECTED TO DRIVE FARTHER SOUTH A BIT TODAY TO INCLUDE NWRN OK. AT THE SFC...A WEAK FRONTAL BOUNDARY IS SITUATED ACROSS THE NORTHERN TX PANHANDLE AND IS CURRENTLY LITTLE MORE THAN A WIND SHIFT LINE. FRONTOGENETICAL FORCING HAS BEEN INSUFFICIENT THUS FAR IN INITIATING CONVECTION. NWP APPEARS FAIRLY CONSISTENT IN PUSHING THIS BOUNDARY SLOWLY SOUTHWARD TODAY IN RESPONSE TO ANEMIC EMBEDDED TROUGH WHICH IS EVIDENT AT H5. THE QUESTION IS WHETHER DYNAMICAL PROCESSES WILL BE SUFFICIENT TO INITIATE CONVECTION ACROSS OUR CWFA THIS AFTERNOON. WHILE OUR AREA IS ON THE SUBSIDENT SIDE OF THE POLAR JET...AND SOME RESEMBLANCE OF A CAP IS EVIDENT ON FCST SOUNDINGS...THE MERE PRESENCE OF THE SURFACE CONVERGENCE WILL BE VERY HELPFUL IN HELPING TO REALIZE TSTM DEVELOPMENT. WHILE BULK SHEAR IS QUITE WEAK...INSTABILITY MAY BE SUFFICIENT FOR A FEW PULSE STRONG TO POSSIBLY SEVERE STORMS TO DEVELOP WITH HAIL TO THE SIZE OF NICKELS AND GUSTS TO AROUND 60 MPH POSSIBLE IN ANY STORMS WHICH MANAGE TO BECOME ESTABLISHED. STORM MOTION WILL BE QUITE SLOW (LESS THAN 10 MPH) AND THUS A FEW LUCKY LOCATIONS MAY PICK UP A QUICK HALF INCH TO AN INCH. HOWEVER...METEOROLOGICAL SCIENCE WITH THE OBSERVATIONAL NETWORK AVAILABLE TODAY IS INSUFFICIENT TO US TO PINPOINT WHERE THAT MIGHT BE OTHER THAN THE NORTHERN ZONES WILL HAVE THE BEST OPPORTUNITY FOR RAIN. LONG TERM... THE EXTENDED FORECAST WILL START OFF WITH CHANCES FOR PRECIP INITIALLY FOR THE SRN TX PANHANDLE/NORTHERN SOUTH PLAINS...THANKS TO A 15-25 KT NOCTURNAL LLJ AND /MOST IMPORTANTLY/ A NRLY COLD FRONT THAT WILL STALL ACROSS THE SRN TX PANHANDLE TONIGHT. THIS FRONT IS IN ASSOCIATION WITH A SUBTLE SHORTWAVE PROGGED TO MOVE SE ACROSS THE CENTRAL PLAINS. THE FRONT WILL LIKELY WASH OUT BY TOMORROW AFTN DURING AT WHICH TIME THE CENTER OF THE UA RIDGE THAT WAS ONCE OVERHEAD WOULD BE SOUTH OF THE REGION. AS SUCH...MONSOONAL STORM ACTIVITY ACROSS E NM COULD SHIFT TO ACROSS WRN ZONES DUE TO ADEQUATE SW STEERING FLOW. THURSDAY NIGHT-FRIDAY CHANCES FOR RAINFALL COULD BECOME REALIZED FOR THE REMAINDER OF THE CWA. A SHARPER SHORTWAVE TROUGH WILL BE SKIRTING SE ACROSS THE CENTRAL PLAINS HEADING TOWARDS OKLAHOMA. THIS WILL CAUSE THE UA RIDGE TO RETROGRADE JUST ENOUGH TO ALLOW FLOW ALOFT TO VEER TO THE NW. ALTHOUGH THE BEST LIFT WILL BE WELL NE OF THE REGION...THE FAVORABLE NW FLOW ALOFT WILL ENCOURAGE MOUNTAINOUS PRECIP ACTIVITY TO TRANSLATE SE ACROSS THE SOUTHERN PLAINS. THEREAFTER...A COLD FRONT WILL MOVE ACROSS THE ENTIRE CWFA FRIDAY EVENING/NIGHT...HENCE BEING ANOTHER SOURCE OF PRECIP DEVELOPMENT AS FRONTOGENETICAL FORCING WORKS WITH AN ENE UPSLOPE WIND COMPONENT. PWATS ARE PROGGED TO INCREASE TO 1.20-1.80 INCHES AND MID-LEVEL CAPE VALUES OF A FEW HUNDRED J/KG SUGGESTS THAT MODERATE RAINFALL AND ISOLATED STRONG STORMS ARE PLAUSIBLE RESPECTIVELY. THIS WEEKEND-EARLY NEXT WEEK...THE UA RIDGE ALBEIT FLATTENED...WILL MAKE A RETURN TO THE SOUTHERN PLAINS THUS CAUSING INCREASING DIFFICULTY IN STORM DEVELOPMENT /MID-LEVEL CAP WILL EXIST/. HOWEVER...ADEQUATE SW MEAN FLOW COULD ONCE AGAIN URGE THE MONSOONAL MOISTURE PLUME/PRECIP TO BEND ACROSS THE WRN AND NWRN ZONES. EARLY NEXT WEEK-MID WEEK...LONG TERM SOLUTIONS HINT AT YET ANOTHER SHORTWAVE TROUGH HAVING THE POTENTIAL TO TAKE THE EXACT SAME TRACK AS THE ONE EXPECTED THURSDAY NIGHT-FRIDAY /PER THE GFS/ OR A BIT FARTHER NE /PER THE ECMWF/. THIS WILL CAUSE THE UA RIDGE TO ONCE AGAIN RETROGRADE AND PROMOTE NW FLOW ALOFT /MOVING STORMS OFF THE MOUNTAINS AND TOWARDS THE FA/...NOT TO MENTION MAKING WAY FOR ANOTHER FRONT AND ACCOMPANIED PRECIP. WILL HOLD OFF ON MENTIONABLE POPS FOR NEXT WEEK AND AWAIT A CONSISTENT QPF SIGNAL. TEMPS WILL COOL OFF INTO THE UPPER 80S TO LOWER 90S BY THE WEEKEND...BUT WILL REBOUND BACK TO ABOVE NORM BY EARLY NEXT WEEK. && .PRELIMINARY POINT TEMPS/POPS... FRIONA 68 91 66 87 65 / 30 20 20 20 20 TULIA 70 91 66 88 65 / 20 20 20 20 20 PLAINVIEW 70 92 67 89 66 / 20 20 20 20 20 LEVELLAND 71 95 68 92 67 / 20 20 20 20 20 LUBBOCK 71 95 70 93 68 / 20 20 20 20 20 DENVER CITY 71 96 68 94 67 / 30 20 20 20 20 BROWNFIELD 72 96 68 94 68 / 20 10 20 20 20 CHILDRESS 72 97 71 94 70 / 10 20 20 20 30 SPUR 74 97 70 95 71 / 20 10 20 20 20 ASPERMONT 74 99 72 97 72 / 20 10 10 20 20 && .LUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 16/23/16
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
559 PM CDT WED JUL 24 2013 UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE .SHORT TERM...TONIGHT AND THURSDAY ISSUED AT 312 PM CDT WED JUL 24 2013 LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW WEAK HIGH PRESSURE STRETCHING FROM THE CENTRAL GREAT PLAINS TO THE CENTRAL GREAT LAKES THIS AFTERNOON. THE WESTERN GREAT LAKES IS FIRMLY ENTRENCHED WITHIN NORTHWEST FLOW ALOFT...AND SEVERAL WEAK SHORTWAVES ARE COMBINING WITH DIURNAL INSTABILITY TO GENERATE A WIDESPREAD DIURNAL CU FIELD. THIS CU IS MOST BUBBLY OVER NORTHERN WISCONSIN AND THE UPPER PENINSULA WHERE THERE ARE A FEW SPECKS ON RADAR INDICATING A FEW LIGHT SHOWERS. LOOKING UPSTREAM...SOME BREAKS IN THE CLOUD COVER OVER NORTHERN MINNESOTA. A SHORTWAVE OVER LAKE WINNIPEG IS PRODUCING SOME THUNDERSTORMS...BUT THAT SHOULD REMAIN NORTH OF THE REGION TONIGHT. THEN THERE IS THE NEXT SIGNIFICANT SYSTEM WHICH IS DIVING SOUTH OVER SASKATCHEWAN AND WILL IMPACT OUR AREA TOMORROW. CLOUDS AND TEMPS ARE THE MAIN FORECAST CONCERNS TONIGHT...FOLLOWED BY LOW SEVERE WEATHER CHANCES TOMORROW. TONIGHT...ISOLATED SHOWERS WILL DIMINISH EARLY THIS EVENING WITH LOSS OF DAYTIME HEATING. HOWEVER...WEAK MID-LEVEL WARM ADVECTION WILL CONTINUE FOR MUCH OF THE NIGHT SO HARD TO GET A HANDLE ON SKY CONDITIONS. SATELLITE SEEMS TO SUGGEST THAT AREAS OF MID-LEVEL CLOUDS WILL LINGER THIS EVENING...AND THEN SOME CLEARING WILL WORK OVERHEAD UNTIL THE NEXT SYSTEM ARRIVES THURSDAY MORNING. WILL DROP CLOUD COVERAGE DURING THE OVERNIGHT PERIOD. MORE CLOUDS/MOISTURE WILL KEEP TEMPS IN THE LOW TO MID 50S. THURSDAY...A STRONG SHORTWAVE WILL MOVE ACROSS LAKE WINNIPEG AND INTO SOUTHWEST ONTARIO. IT WILL PUSH A WEAK FRONT FROM NE MINNESOTA TO NORTHWEST WISCONSIN OVER THE COURSE OF THE DAY. STRENGTHENING SOUTHWEST FLOW AHEAD OF THE FRONT WILL BRING IN INCREASING AMOUNTS OF MOISTURE...AS MODELS SHOW PWATS INCREASING TO AROUND 1.5 INCHES FROM ABOUT AN INCH AT THE START OF THE DAY. WARM ADVECTION TO OCCUR THROUGH THE DAY IS NOT ALL THAT STRONG...BUT WITH AMPLE MOISTURE AND ML CAPES INCREASING TO 900-1400 J/KG IN THE AFTERNOON...CAN ENVISION STORMS INITIATING LATE IN THE MORNING OR EARLY AFTERNOON AND THEN BUILDING DURING THE AFTERNOON. IF ANY KIND OF MORNING CLOUD COVER DOES NOT HOLD BACK HEATING...30-35KTS OF 0-6KM BULK SHEAR WOULD SUPPORT AN ISOLATED SEVERE THREAT. FORCING IS ON THE WEAKER SIDE...SO DO NOT THINK ANY SORT OF WIDESPREAD OUTBREAK IS POSSIBLE...BUT A SCATTERED COVERAGE OF STORMS ALONG WITH AN ISOLATED SEVERE THREAT SEEMS REASONABLE. STORMS SHOULD ALSO BE RATHER PULSIE IN NATURE. HIGHS RETURNING TO THE MID AND UPPER 70S. .LONG TERM...THURSDAY NIGHT THROUGH WEDNESDAY ISSUED AT 312 PM CDT WED JUL 24 2013 THE SERVER CRASHED RIGHT AS WE WERE GOING TO ISSUE THE AFD AND LOST THIS PART OF THE DISCUSSION. SINCE THE LONG TERM FORECAST HAD TO LEAVE AT 3PM...WILL HAVE TO MAKE THIS SHORT AND SWEET. THURSDAY NIGHT THROUGH FRIDAY NIGHT...CONVECTION ALONG AND AHEAD OF THE COLD FRONT WILL BE ONGOING THURSDAY NIGHT. DETAILS START TO GET MORE MURKY BY THIS POINT...BUT FORCING IMPROVES THURSDAY NIGHT AS A LOBE OF THE STRONG SHORTWAVE OVER ONTARIO DROPS SOUTHEAST INTO WESTERN LAKE SUPERIOR. ELEVATED CAPE WILL BE DIMINISHING THROUGH THE NIGHT DESPITE FORCING IMPROVING AND PWATS AROUND 1.5 INCHES. MODELS HAVE DIFFERENT SCENARIOS PLAYING OUT THURSDAY NIGHT...WITH SOME GUIDANCE HINTING AT AN MCS MOVING OVER CENTRAL WISCONSIN AND THE FOX VALLEY. THE FRONT WILL FINISH CROSSING THE REGION FRIDAY MORNING AND MUCH COLDER AIR WILL FILTER IN BEHIND THE FRONT. SOME SHOWERS AND THUNDERSTORMS LOOK LIKELY AHEAD OF THE FRONT...AND THEN SCATTERED SHOWERS SHOULD LINGER THROUGH DAY BEHIND THE FRONT WITH THE SHORTWAVE OVERHEAD. WITH CLOUDY AND SHOWERY WEATHER...TEMPS WILL STRUGGLE TO REACH THE MID 60S NORTH TO MID 70S SOUTH...AND COULD BE LOOKING AT MORNING HIGHS. REMAINING CLOUDY FRIDAY NIGHT THOUGH SHOWERS SHOULD BE DIMINISHING. BREEZY AND COOL WITH LOWS IN THE 40S TO LOW 50S. REST OF THE FORECAST....CONTINUED CLOUDY AND COOL ON SATURDAY WITH A FEW SHOWERS POSSIBLE COMING OFF LAKE SUPERIOR INTO NORTHERN WISCONSIN. DROPPED HIGHS SEVERAL DEGREES DUE TO CLOUD COVER AND 925MB TEMPS IN THE UPPER SINGLE DIGITS. CLOUDS AND SHOWERS POSSIBLY TO HANG AROUND INTO SUNDAY BEFORE THE UPPER LOW FINALLY DEPARTS. HIGH PRESSURE WILL BE OVER THE AREA ON MONDAY WHEN TEMPS MODERATE SOME. THEN THE NEXT CHANCE OF RAIN ARRIVES TUESDAY INTO WEDNESDAY. && .AVIATION...FOR 00Z TAF ISSUANCE ISSUED AT 514 PM CDT WED JUL 24 2013 ISOLATED LIGHT SHOWERS WILL DISSIPATE THIS EVENING OTHERWISE VFR CONDITIONS TO PREVAIL TONIGHT INTO THURSDAY. THE CHANCE OF SHOWERS AND STORMS WILL BE ON THE INCREASE FROM NORTHWEST TO SOUTHEAST AS A COLD FRONT DROPS INTO NORTHWEST WISCONSIN THURSDAY AFTERNOON AND THEN INTO SOUTHEAST WISCONSIN THURSDAY NIGHT. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....MPC LONG TERM......MPC AVIATION.......TDH
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE

.SHORT TERM...TONIGHT AND THURSDAY ISSUED AT 312 PM CDT WED JUL 24 2013 LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW WEAK HIGH PRESSURE STRETCHING FROM THE CENTRAL GREAT PLAINS TO THE CENTRAL GREAT LAKES THIS AFTERNOON. THE WESTERN GREAT LAKES IS FIRMLY ENTRENCHED WITHIN NORTHWEST FLOW ALOFT...AND SEVERAL WEAK SHORTWAVES ARE COMBINING WITH DIURNAL INSTABILITY TO GENERATE A WIDESPREAD DIURNAL CU FIELD. THIS CU IS MOST BUBBLY OVER NORTHERN WISCONSIN AND THE UPPER PENINSULA WHERE THERE ARE A FEW SPECKS ON RADAR INDICATING A FEW LIGHT SHOWERS. LOOKING UPSTREAM...SOME BREAKS IN THE CLOUD COVER OVER NORTHERN MINNESOTA. A SHORTWAVE OVER LAKE WINNIPEG IS PRODUCING SOME THUNDERSTORMS...BUT THAT SHOULD REMAIN NORTH OF THE REGION TONIGHT. THEN THERE IS THE NEXT SIGNIFICANT SYSTEM WHICH IS DIVING SOUTH OVER SASKATCHEWAN AND WILL IMPACT OUR AREA TOMORROW. CLOUDS AND TEMPS ARE THE MAIN FORECAST CONCERNS TONIGHT...FOLLOWED BY LOW SEVERE WEATHER CHANCES TOMORROW. TONIGHT...ISOLATED SHOWERS WILL DIMINISH EARLY THIS EVENING WITH LOSS OF DAYTIME HEATING. HOWEVER...WEAK MID-LEVEL WARM ADVECTION WILL CONTINUE FOR MUCH OF THE NIGHT SO HARD TO GET A HANDLE ON SKY CONDITIONS. SATELLITE SEEMS TO SUGGEST THAT AREAS OF MID-LEVEL CLOUDS WILL LINGER THIS EVENING...AND THEN SOME CLEARING WILL WORK OVERHEAD UNTIL THE NEXT SYSTEM ARRIVES THURSDAY MORNING. WILL DROP CLOUD COVERAGE DURING THE OVERNIGHT PERIOD. MORE CLOUDS/MOISTURE WILL KEEP TEMPS IN THE LOW TO MID 50S. THURSDAY...A STRONG SHORTWAVE WILL MOVE ACROSS LAKE WINNIPEG AND INTO SOUTHWEST ONTARIO. IT WILL PUSH A WEAK FRONT FROM NE MINNESOTA TO NORTHWEST WISCONSIN OVER THE COURSE OF THE DAY. STRENGTHENING SOUTHWEST FLOW AHEAD OF THE FRONT WILL BRING IN INCREASING AMOUNTS OF MOISTURE...AS MODELS SHOW PWATS INCREASING TO AROUND 1.5 INCHES FROM ABOUT AN INCH AT THE START OF THE DAY. WARM ADVECTION TO OCCUR THROUGH THE DAY IS NOT ALL THAT STRONG...BUT WITH AMPLE MOISTURE AND ML CAPES INCREASING TO 900-1400 J/KG IN THE AFTERNOON...CAN ENVISION STORMS INITIATING LATE IN THE MORNING OR EARLY AFTERNOON AND THEN BUILDING DURING THE AFTERNOON. IF ANY KIND OF MORNING CLOUD COVER DOES NOT HOLD BACK HEATING...30-35KTS OF 0-6KM BULK SHEAR WOULD SUPPORT AN ISOLATED SEVERE THREAT. FORCING IS ON THE WEAKER SIDE...SO DO NOT THINK ANY SORT OF WIDESPREAD OUTBREAK IS POSSIBLE...BUT A SCATTERED COVERAGE OF STORMS ALONG WITH AN ISOLATED SEVERE THREAT SEEMS REASONABLE. STORMS SHOULD ALSO BE RATHER PULSIE IN NATURE. HIGHS RETURNING TO THE MID AND UPPER 70S. .LONG TERM...THURSDAY NIGHT THROUGH WEDNESDAY ISSUED AT 312 PM CDT WED JUL 24 2013 THE SERVER CRASHED RIGHT AS WE WERE GOING TO ISSUE THE AFD AND LOST THIS PART OF THE DISCUSSION. SINCE THE LONG TERM FORECAST HAD TO LEAVE AT 3PM...WILL HAVE TO MAKE THIS SHORT AND SWEET. THURSDAY NIGHT THROUGH FRIDAY NIGHT...CONVECTION ALONG AND AHEAD OF THE COLD FRONT WILL BE ONGOING THURSDAY NIGHT. DETAILS START TO GET MORE MURKY BY THIS POINT...BUT FORCING IMPROVES THURSDAY NIGHT AS A LOBE OF THE STRONG SHORTWAVE OVER ONTARIO DROPS SOUTHEAST INTO WESTERN LAKE SUPERIOR. ELEVATED CAPE WILL BE DIMINISHING THROUGH THE NIGHT DESPITE FORCING IMPROVING AND PWATS AROUND 1.5 INCHES. MODELS HAVE DIFFERENT SCENARIOS PLAYING OUT THURSDAY NIGHT...WITH SOME GUIDANCE HINTING AT AN MCS MOVING OVER CENTRAL WISCONSIN AND THE FOX VALLEY. THE FRONT WILL FINISH CROSSING THE REGION FRIDAY MORNING AND MUCH COLDER AIR WILL FILTER IN BEHIND THE FRONT. SOME SHOWERS AND THUNDERSTORMS LOOK LIKELY AHEAD OF THE FRONT...AND THEN SCATTERED SHOWERS SHOULD LINGER THROUGH DAY BEHIND THE FRONT WITH THE SHORTWAVE OVERHEAD. WITH CLOUDY AND SHOWERY WEATHER...TEMPS WILL STRUGGLE TO REACH THE MID 60S NORTH TO MID 70S SOUTH...AND COULD BE LOOKING AT MORNING HIGHS. REMAINING CLOUDY FRIDAY NIGHT THOUGH SHOWERS SHOULD BE DIMINISHING. BREEZY AND COOL WITH LOWS IN THE 40S TO LOW 50S. REST OF THE FORECAST....CONTINUED CLOUDY AND COOL ON SATURDAY WITH A FEW SHOWERS POSSIBLE COMING OFF LAKE SUPERIOR INTO NORTHERN WISCONSIN. DROPPED HIGHS SEVERAL DEGREES DUE TO CLOUD COVER AND 925MB TEMPS IN THE UPPER SINGLE DIGITS. CLOUDS AND SHOWERS POSSIBLY TO HANG AROUND INTO SUNDAY BEFORE THE UPPER LOW FINALLY DEPARTS. HIGH PRESSURE WILL BE OVER THE AREA ON MONDAY WHEN TEMPS MODERATE SOME. THEN THE NEXT CHANCE OF RAIN ARRIVES TUESDAY INTO WEDNESDAY. && .AVIATION...FOR 18Z TAF ISSUANCE ISSUED AT 1243 PM CDT WED JUL 24 2013 AFTERNOON INSTABILITY WILL HELP GENERATE SCT SHOWERS AND PERHAPS AN ISOLATED THUNDERSTORM THIS AFTERNOON OVER NORTH-CENTRAL WISCONSIN. ANY SHOWERS WILL LIKELY DISSIPATE EARLY THIS EVENING...BUT BROKEN MID-CLOUDS WILL PERSIST ACROSS MUCH OF NORTHERN AND NORTHEAST WISCONSIN THROUGH THE EVENING IF NOT LONGER. A COLD FRONT WILL THEN MOVE INTO NORTHWEST WISCONSIN TOMORROW...WHICH WILL BRING BACK A CHANCE OF SHOWERS AND THUNDERSTORMS TO NORTH-CENTRAL WISCONSIN BY LATE IN THE MORNING. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....MPC LONG TERM......MPC AVIATION.......MPC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1154 AM CDT WED JUL 24 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 345 AM CDT WED JUL 24 2013 MAIN FORECAST CONCERNS ARE ON SHOWER AND THUNDERSTORM CHANCES THURSDAY INTO THURSDAY NIGHT WITH THE POTENTIAL FOR SEVERE THUNDERSTORMS. FOCUS THEN TURNS TO TEMPERATURES FRIDAY THROUGH THE WEEKEND. LATEST WATER VAPOR IMAGERY SHOWED NORTHWEST FLOW ALOFT OVER THE UPPER MISSISSIPPI RIVER VALLEY EXTENDING NORTHWEST THROUGH SOUTHERN ALBERTA. SEVERAL EMBEDDED SHORTWAVES WERE NOTED WITHIN THE NORTHWEST FLOW. SURFACE OBSERVATIONS SHOWED HIGH PRESSURE IN CONTROL OVER THE REGION PROVIDING QUIET CONDITIONS. SOME MID AND HIGH LEVEL CLOUDS WERE MOVING ACROSS THE REGION EARLY THIS MORNING. THE CLOUDS COUPLED WITH THE DRIER AIR IN PLACE OVER THE REGION HAVE PREVENTED THE FORMATION OF FOG SO FAR. CANNOT RULE OUT SOME PATCHY FOG EARLY THIS MORNING BUT THIS SHOULD QUICKLY DISSIPATE AS MIXING INCREASES AFTER SUNRISE. THE HIGH WILL SLIDE EAST OF THE AREA TODAY AS A COLD FRONT SLIDES INTO THE EASTERN DAKOTAS AND EDGES EAST. SOME WEAK MOISTURE TRANSPORT COMBINED WITH 0-3KM MUCAPE VALUES OF AROUND 500 J/KG MAY BE ENOUGH TO PRODUCE ISOLATED SHOWERS AND THUNDERSTORMS OVER SOUTH CENTRAL MINNESOTA AND POSSIBLY PORTIONS OF SOUTHEAST MINNESOTA. THE BULK OF THIS ACTIVITY WILL LIKELY HAVE A DIFFICULT TIME MAKING IT EAST OF THE INTERSTATE 35 CORRIDOR AS IT ENCOUNTERS MUCH DRIER AIR. WILL HAVE TO KEEP A CLOSE EYE ON THIS...THE HRRR AND HI RES ARW ARE BOTH PRODUCING LIGHT PRECIPITATION ALONG THE I-35 CORRIDOR AND EDGES JUST EAST POSSIBLY IMPACTING DODGE AND MOWER COUNTIES DURING THE AFTERNOON HOURS. OTHERWISE...PLAN ON SOME PASSING MID AND HIGH LEVEL CLOUDS TODAY PROVIDING PARTLY SUNNY SKIES. ANOTHER DAY OF PLEASANT TEMPERATURES WITH HIGHS IN THE LOWER TO MID 70S. THE COLD FRONT CONTINUES TO ADVANCE SOUTHEAST TONIGHT AND BY THE LATE NIGHT HOURS LOOKS TO BE POSITIONED FROM THE ARROWHEAD OF MINNESOTA SOUTH THROUGH CENTRAL INTO SOUTHWEST MINNESOTA. IT THEN SLOWS AND STALLS AS IT EDGES INTO NORTHWEST WISCONSIN BY EARLY THURSDAY MORNING. 850 MB MOISTURE TRANSPORT EDGES INTO SOUTHEAST MINNESOTA AND WEST CENTRAL INTO NORTH CENTRAL WISCONSIN LATE TONIGHT INTO EARLY THURSDAY MORNING. ISOLATED SHOWERS AND THUNDERSTORMS COULD MOVE INTO THESE AREAS EARLY IN THE MORNING. OTHERWISE...PLAN ON PARTLY CLOUDY SKIES DURING THE OVERNIGHT HOURS WITH LOW TEMPERATURES RANGING FROM THE MID TO UPPER 50S. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 345 AM CDT WED JUL 24 2013 THE COLD FRONT SLIDES SOUTHEAST INTO THE FORECAST AREA ON THURSDAY AS A VIGOROUS UPPER LEVEL TROUGH DIVES SOUTHEAST OUT OF SOUTHERN MANITOBA/SASKATCHEWAN. SOUTH/SOUTHWEST FLOW INTO THE AREA AHEAD OF THE FRONT WILL HELP TO BOOST DEWPOINTS INTO THE MID TO UPPER 60S BY EARLY AFTERNOON. THE NAM SHOWS 0-3KM MUCAPE VALUES CLIMBING TO AROUND 3500 J/KG. THE GFS SHOWS SLIGHTLY LOWER VALUES IN THE 2000 TO 3000 J/KG RANGE. THE ECMWF ISN/T SO AGGRESSIVE...INDICATING VALUES IN THE 1200 TO 1600 J/KG RANGE. THE STRONGEST 0-6KM SHEAR LAGS BEHIND THE FRONT. HOWEVER...THERE LOOKS TO BE SUFFICIENT SHEAR TO SUPPORT A SEVERE THREAT WITH 0-6KM BULK SHEAR VALUES HOVERING IN THE 30 TO 35 KT RANGE THURSDAY AFTERNOON INTO THURSDAY EVENING. THUNDERSTORMS ARE EXPECTED TO DEVELOP ALONG THE FRONT THURSDAY AFTERNOON AND HEAD EAST SOUTHEAST ACROSS THE FORECAST AREA. SOME OF THESE STORMS MAY BECOME SEVERE WITH LARGE HAIL AND DAMAGING WINDS. WILL ALSO HAVE TO KEEP AN EYE ON THE POTENTIAL FOR AN ISOLATED TORNADO OR TWO WITH ANY STORMS THAT GO UP ALONG THE BOUNDARY. SHOWERS AND THUNDERSTORMS ARE LIKELY ACROSS THE AREA THURSDAY NIGHT AS THE COLD FRONT MOVES THROUGH. THE SEVERE WEATHER THREAT WILL LINGER THROUGH THE EVENING HOURS BUT SHOULD THEN WANE DURING THE OVERNIGHT HOURS AS CONVECTION BECOMES WIDESPREAD. THE FRONT FINALLY EXITS THE AREA BY FRIDAY AFTERNOON AS THE TROUGH DIVES INTO THE UPPER MISSISSIPPI RIVER VALLEY. AN UNSEASONABLY COOL AIRMASS MOVES INTO THE REGION IN THE WAKE OF THE FRONT. 850 MB TEMPERATURE STANDARDIZED ANOMALIES FALL INTO THE -2.0 TO -3.0 RANGE...INDICATIVE OF NEAR RECORD LOW MAX AND MIN TEMPERATURES. THE COLDEST AIR ALOFT MOVES OVER THE REGION DURING THE DAY ON SATURDAY...WHEN HIGHS WILL STRUGGLE TO GET OUT OF THE 60S. THE LOWEST HIGH TEMPERATURE AT LA CROSSE FOR JULY 27 IS 69 DEGREES...SET BACK IN 1981. THE LOWEST HIGH TEMPERATURE FOR ROCHESTER IS 64 AND WAS ALSO SET BACK IN 1981. LA CROSSE LOOKS TO BE VERY CLOSE TO REACHING THIS RECORD. CURRENT THINKING IS THAT LA CROSSE WILL SEE A HIGH OF 71...BUT IF THE GEM AND ECMWF VERIFY...THIS FORECAST HIGH TEMPERATURE COULD BE 3 TO 4 DEGREES HIGH. THE UPPER TROUGH WILL REMAIN OVER THE WESTERN GREAT LAKES THROUGH THE REMAINDER OF THE WEEKEND WITH COOL SURFACE HIGH PRESSURE IN CONTROL. PLAN ON HIGHS ON SATURDAY RANGING FROM THE MID 60S OVER FAR NORTHERN WISCONSIN TO AROUND 71 ACROSS FAR SOUTHWEST WISCONSIN. TEMPS WILL WARM A BIT ON SUNDAY AS THE TROUGH STARTS TO SHIFT EAST AND SURFACE WINDS TURN WESTERLY. HIGH TEMPERATURES ON SUNDAY ARE EXPECTED TO CLIMB INTO THE LOWER 70S UNDER MOSTLY SUNNY SKIES. THE UPPER TROUGH FINALLY PUSHES EAST OF THE REGION EARLY NEXT WEEK WITH FLOW ALOFT TURNING QUASI ZONAL. FORECAST MODELS SHOWING SOME DIFFERENCES IN THE HANDLING OF THE UPPER LEVEL PATTERN OVER THE CONUS. THE GFS TRIES TO BUILD A RIDGE OVER THE THE HIGH PLAINS WHILE THE ECMWF LEANS TOWARD AN ACTIVE QUASI ZONAL FLOW ALOFT WITH EMBEDDED SHORTWAVES BRINGING SHOWERS AND STORMS TO THE FORECAST AREA. HAVE LEANED TOWARD A MODEL CONSENSUS BLEND FOR THE FIRST PART OF THE WORK WEEK...WITH HIGHS WARMING TO MORE SEASONABLE VALUES WITH HIGHS IN THE UPPER 70S TO AROUND 80 AND CHANCES FOR SHOWERS AND THUNDERSTORMS MONDAY INTO TUESDAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1154 AM CDT WED JUL 24 2013 VFR CONDITIONS ARE EXPECTED THROUGH TOMORROW MORNING AS A COLD FRONT STALLS OUT JUST TO THE WEST OF THE REGION. CLOUD COVER WILL VARY THROUGH THIS AFTERNOON WITH SCT-BKN CEILINGS BETWEEN 4KFT TO 8KFT. AS A RIDGE OF HIGH PRESSURE SHIFTS TO THE EAST...WINDS WILL COME AROUND TO THE SOUTH THIS EVENING AND PICK UP TO AROUND 10-12KT BY TOMORROW MORNING. RAIN SHOWERS AND THUNDERSTORMS ARE POSSIBLE TOMORROW AFTERNOON...JUST AFTER THIS TAF PERIOD ENDS. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...WETENKAMP LONG TERM...WETENKAMP AVIATION...HALBACH