Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 07/20/12
AREA FORECAST DISCUSSION
NWS NEW YORK NY
251 PM EDT WED JUL 18 2012
.SYNOPSIS...
A SLOW MOVING COLD FRONT FROM THE NORTH WILL MOVE INTO THE REGION
THIS AFTERNOON AND SOUTH OF THE REGION LATE TONIGHT INTO THURSDAY.
THE FRONT WILL THEN STALL WITH A WEAK AREA OF LOW PRESSURE MOVING
ALONG IT. LOW PRESSURE PASSES TO THE SOUTH ON FRIDAY WITH HIGH
PRESSURE BUILDING IN FROM THE NORTH THROUGH THE WEEKEND. ANOTHER
COLD FRONT WILL TRACK ACROSS THE AREA ON TUESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
UPDATED GRIDS TO INCREASE MAX TEMPS. HEAT ADVISORY HAS BEEN
EXPANDED TO ALL BUT SOUTHERN MIDDLESEX/NEW LONDON COUNTIES PER
OBS. ADDED ENHANCED SEVERE TSTM WORDING TO THE FORECAST AS SPC HAS
ISSUED SEVERE TSTM WATCH TIL 9PM. MAX TEMPS HAVE LIKELY BEEN
REACHED IN MOST PLACES AS TSTMS ARE DEVELOPING RAPIDLY. SOME
RECORD HIGHS NEARED OR EXCEEDED...SEE CLIMATE SECTION BELOW.
OTHERWISE...A SLOW MOVING COLD FRONT FROM THE NORTH WILL MOVE INTO
THE REGION THIS AFTERNOON. WITH THE REGION BEING ON THE NE EDGE OF
A VERY HOT AIR MASS...DAY STARTS OUT VERY WARM AND LARGE CAPE IN
THE 2000 TO 4000 J/KG RANGE IS EXPECTED TO BUILD WITH DIURNAL
WARMING. SHEAR OF 30 KT 0-6KM WITH WET BULB ZERO HEIGHTS OF 13-14
KFT. MENTIONED GUSTY WINDS AND SMALL HAIL WITH SOME CELLS HAVING A
SLIGHT CHANCE OF GOING SEVERE.
BEFORE COVERAGE OF SHOWERS AND THUNDERSTORMS BECOMES
WIDESPREAD...AT LEAST SOUTHERN PORTIONS OF THE REGION WILL SEE
ENOUGH SUN TO HAVE HIGHS WELL INTO THE 90S AND WITH VERY MOIST
AIR MASS CONVEYED BY PWATS NEAR 2 INCHES AND DEWPOINTS IN THE LOWER
70S...HEAT INDICES ARE EXPECTED TO BE NEAR 100 DEGREES FOR NEW
YORK CITY AS WELL AS URBAN SECTIONS OF SOUTHERN WESTCHESTER...MOST
OF NE NJ AND WESTERN LONG ISLAND.
FARTHER UP NORTH IN LOWER HUDSON VALLEY AND SOUTHERN CT WILL DEPEND
ON HOW FAST CONVECTION DEVELOPS AND THE INHERENT MITIGATION OF
DIURNAL WARMTH ASSOCIATED WITH EXPANDING CIRRUS CLOUD SHIELD OF
CONVECTION. RIGHT NOW...KEPT THEM LOWER WITHOUT HEAT ADVISORY BUT
HEAT INDICES ARE EXPECTED TO REACH MID TO UPPER 90S BEFORE
CONVECTION INCREASES SUBSTANTIALLY IN COVERAGE THIS AFTERNOON.
WILL START OFF THE HEAT ADVISORY LATE THIS MORNING BY 10 AM SINCE WE
WILL BE COMMENCING THE DIURNAL PERIOD AT A MUCH WARMER TEMPERATURE
THIS MORNING. MOST MODELS START TO BRING IN THE SHOWERS AND
THUNDERSTORMS BY 18Z ACROSS THE NORTHERN TIER AND BY 00Z ACROSS THE
ENTIRE AREA. ONLY EXCEPTION IS ECMWF WHICH HAS CONSISTENTLY HELD
BACK CONVECTION FOR LONG ISLAND UNTIL AFTER 00Z THU.
BASED ON MESOSCALE MODELS OF HRRR AND NSSL WRF...STRENGTHENING
CONVECTIVE CELLS START FIRING UP ALONG ACROSS THE ALLEGHENY PLATEAU
AND THE HUDSON VALLEY AROUND 17Z AFTER WHICH THEY WILL BE ON A
SOUTHEAST TRACK GOING INTO THE LOCAL FORECAST REGION. FURTHER
DEVELOPMENT OF CONVECTION COULD ALSO OCCUR FROM CONVERGENCE ALONG
THE SEA BREEZE BOUNDARY ESPECIALLY WITH ANY OUTFLOW BOUNDARIES FROM
CONVECTION MOVING IN FROM THE NORTH AND WEST. WIND SHEAR OF 25 TO 30
KT FROM 0-6 KM WILL ALLOW FOR SOME THUNDERSTORMS TO PRODUCE HAIL AND
GUSTY WINDS. PWATS NEAR 2 INCHES SO HEAVY RAIN ALSO CAN BE EXPECTED
WITH THUNDERSTORMS THAT FORM. THIS IS CONSIDERED ESPECIALLY SINCE
THE FLOW WILL BE NEARLY PARALLEL FROM LOW TO MID LEVELS WHICH WOULD
ALLOW FOR TRAINING OF CELLS. THE CONVECTIVE MODE LOOKS TO BE SQUALL
LINE TO BOW ECHOES.
THERE IS A MODERATE RISK FOR RIP CURRENTS TODAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/...
TONIGHT...RELATIVELY BETTER SHEAR ARRIVES WITH WINDS ALOFT AT 250MB
INCREASING AN EXTRA 10KT...PROMOTING GREATER DIVERGENCE. SOME
GREATER HEIGHT FALLS AT 500MB WILL ALSO IMPLY SOME GREATER SYNOPTIC
FORCING. THEREFORE EVEN THOUGH CAPE WILL BE ON A LOWERING
TREND...SOME THUNDERSTORMS WILL STILL MAINTAIN STRONG INTENSITIES
WITH HEAVY RAIN ALSO STILL POSSIBLE AS PWATS REMAIN NEAR 2 INCHES.
THE FRONT MOVES THROUGH LATE IN THE EVENING AND THEN SOUTH OF LONG
ISLAND GOING INTO THURSDAY. THE FRONT STALLS WITH A WEAK AREA OF LOW
PRESSURE MOVING IT. SOUTHERN PORTIONS OF THE FORECAST AREA COULD SEE
SOME LINGERING SHOWERS FROM TIME TO TIME ON THURSDAY AS A RESULT.
POPS ARE AT SLIGHT CHANCE WITH MODEL UNCERTAINTY DUE TO DIFFERENCES
IN QPF FIELDS AND RUN TO RUN INCONSISTENCY. IN THE UPPER LEVELS AT
500MB...THE AREA WILL BE IN A NW FLOW WITH A LONGWAVE TROUGH SETTING
UP ACROSS THE NORTHEAST. WENT WITH MORE OF THE COOLER GUIDANCE FOR
HIGHS CONSIDERING THE MORE EASTERLY FLOW. NOT EXPECTING ANY
THUNDERSTORMS WITH THIS ACTIVITY WITH MORE STABLE SFC CONDITIONS
FORECAST.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
A MEAN TROUGH WILL REMAIN OVER THE NE CONUS THROUGH THE PERIOD WHILE
A PERSISTENT AND STRONG RIDGE ALOFT REMAINS ENTRENCHED OVER THE
PLAINS AND ROCKIES.
COLD FRONT SLOWLY PRESSES SOUTHWARD THROUGH THE MID ATLANTIC STATES
THROUGH FRIDAY WITH CANADIAN HIGH PRES BUILDING IN FROM THE N. AN
AREA OF LOW PRES IS FORECAST TO DEVELOP ON THE FRONT THU NIGHT AND
PASS TO THE S FRI MORNING WITH AN UPPER LEVEL TROUGH SWINGING
THROUGH ALOFT. AN EASTERLY FLOW WILL MOISTEN LOW LEVELS WITH THE CHC
OF SHOWERS ON FRI. MODELS HAVE BEEN CONSISTENT WITH THIS FOR THE
LAST DAY...SO HAVE ADDED CHC POPS TO THE FORECAST. ABUNDANT CLOUD
COVER AND ONSHORE FLOW WILL RESULT IN A MUCH COOLER DAY ACROSS THE
AREA WITH HIGHS ONLY EXPECTED TO REACH THE UPPER 70S AT MOST
LOCATIONS. AS THE FRONT SINKS FURTHER S LATER FRI AND FRI NIGHT
DRIER AND MORE STABLE AIR WILL WORK IN FROM THE N AND E WITH DRY
WEATHER AND SEASONABLE THROUGH THE WEEKEND.
WAA ENSUES EARLY NEXT WEEK WITH H85 TEMPS RISING INTO THE UPPER
TEENS ON MON RESULTING IN TEMPS RISING A FEW DEGREES ABOVE NORMAL
LEVELS MON. PRE-FRONTAL TROUGH MAY TRIGGER ISOLD-SCT STORMS MON AFTN
AS COLD FRONT APPROACHES FROM THE NW. TYPICAL GFS IS FASTER THAN THE
EC WITH THE FROPA SO HAVE COMPROMISED THE TIMING WITH IT COMING
THROUGH TUE MORNING. DRY AND SEASONABLE WEATHER COURTESY OF HIGH
PRES THEN BUILDS BACK IN OVER THE AREA.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
A COLD FRONT WILL APPROACH THIS AFTERNOON...AND PASS TO THE SOUTH
TONIGHT.
AT 1815Z...RADAR SHOWED BKN LINE OF STRONG TO SEVERE TSTMS
EXTENDING ACROSS NW NJ...THE LOWER HUDSON VALLEY AND CT...WITH
MORE ISOLD ACTIVITY ALONG THE NORTH SHORE OF LONG ISLAND...ALL
MOVING E TO E-SE. MAIN IMPACTS BEFORE 21Z WILL BE JUST NORTH OF
THE NYC METRO TERMINALS AT KHPN/KBDR...BUT GUST FRONT FROM THESE
STORMS SHOULD ALSO IMPACT KTEB/KLGA WITH A WIND SHIFT FROM THE
NW. MAIN IMPACT TO NYC METRO TERMINALS WILL ARRIVE AFTER 21Z AS
STORMS OVER EASTERN/NE PA AND FAR WRN NJ APPROACH. THREAT OF
STRONG WINDS AND CONVECTIVE LLWS...HAIL AND HEAVY RAINFALL
EXISTS...AND COULD CONTINUE UNTIL 00Z-01Z.
MAINLY VFR LATER THIS EVENING AFTER CONVECTION WEAKENS AND PASSES
TO THE SOUTH...WITH LIGHT N FLOW DEVELOPING AFTER COLD FROPA.
CANNOT RULE OUT SOME PATCHY GROUND FOG AT OUTLYING TERMINALS.
...NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS
CAN BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KJFK FCSTER COMMENTS: MAIN IMPACTS FROM TSTMS 22Z-01Z.
KLGA FCSTER COMMENTS: MAIN IMPACTS FROM TSTMS 22Z-01Z.
KEWR FCSTER COMMENTS: MAIN IMPACTS FROM TSTMS 21Z-24Z.
KTEB FCSTER COMMENTS: MAIN IMPACTS FROM TSTMS 21Z-24Z.
KHPN FCSTER COMMENTS:
KISP FCSTER COMMENTS: MAIN IMPACTS FROM TSTMS 23Z-01Z.
OUTLOOK FOR 18Z THU THROUGH MON...
.THU AFTERNOON-EVENING...VFR. ISOLD SHOWERS POSSIBLE.
.LATE THU NIGHT-SAT MORNING...SCAT SHOWERS AND MVFR CONDS
POSSIBLE...BEST CHANCE AT SOUTHERN/COASTAL TERMINALS.
.SAT AFTERNOON-SUN NIGHT...VFR.
.MON...CHANCE OF TSTMS.
&&
.MARINE...
MARGINAL SCA CONDITIONS ARE POSSIBLE AT TIMES ACROSS OUTER OCEAN
WATERS IN THE SHORT TERM THROUGH THURSDAY NIGHT. HOWEVER...KEPT
OCEAN SEAS BELOW 5 FT SINCE WAVEWATCH INITIALLY ABOUT A FOOT TOO
HIGH COMPARED TO OBS.
MARGINAL SCA CONDS ARE POSSIBLE ON THE OCEAN WATERS FRI/FRI NIGHT
WITH AN INCREASING EASTERLY FLOW BETWEEN HIGH PRES BUILDING IN FROM
THE N AND LOW PRES PASSING TO THE S. A RELATIVELY LIGHT SE-S FLOW
WILL THEN PREVAIL WITH SUB-ADVY CONDS THEREAFTER. HAVE CUT A FT OFF
OF WAVEWATCH GUIDANCE THROUGH THE PERIOD AS IT CONTINUES TO RUN
HIGH.
&&
.HYDROLOGY...
NO PRECIPITATION IS EXPECTED INTO THIS MORNING.
FLASH FLOODING IS POSSIBLE WITH ANY TRAINING CONVECTION THIS
AFTERNOON AND EVENING AS PWATS INCREASE TO AROUND 2 INCHES AND
STEERING FLOW NEARLY ALIGNS WITH FRONTAL BOUNDARY. A BASIN AVERAGE
QPF OF AROUND 1/4 TO 1/2 INCH IS POSSIBLE ACROSS THE AREA...WITH
LOCALIZED AMOUNTS IN EXCESS OF 2 INCHES POSSIBLE WITH ANY TRAINING
CONVECTION.
&&
.CLIMATE...
NEWARK HAS BROKEN THEIR RECORD HIGH TODAY WITH A MAX OF 103 DEGREES SO
FAR. LA GUARDIA ARPT HAS HIT 100 DEGREES...WHICH TIES THEIR RECORD.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...HEAT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR CTZ005>010.
NY...HEAT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR NYZ067>075-
078>081-176>179.
NJ...HEAT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR NJZ002-004-006-
103>108.
MARINE...NONE.
&&
$$
SYNOPSIS...JM
NEAR TERM...JM
SHORT TERM...JM
LONG TERM...24
AVIATION...GOODMAN
MARINE...24/JM
HYDROLOGY...24/JM
CLIMATE...
AREA FORECAST DISCUSSION
NWS NEW YORK NY
102 PM EDT WED JUL 18 2012
.SYNOPSIS...
A SLOW MOVING COLD FRONT FROM THE NORTH WILL MOVE INTO THE REGION
THIS AFTERNOON AND SOUTH OF THE REGION LATE TONIGHT INTO THURSDAY.
THE FRONT WILL THEN STALL WITH A WEAK AREA OF LOW PRESSURE MOVING
ALONG IT. LOW PRESSURE PASSES TO THE SOUTH ON FRIDAY WITH HIGH
PRESSURE BUILDING IN FROM THE NORTH THROUGH THE WEEKEND. ANOTHER
COLD FRONT WILL TRACK ACROSS THE AREA ON TUESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
UPDATED GRIDS TO INCREASE MAX TEMPS. HEAT ADVISORY HAS BEEN
EXPANDED TO ALL BUT SOUTHERN MIDDLESEX/NEW LONDON COUNTIES PER
OBS. ADDED ENHANCED SEVERE TSTM WORDING TO THE FORECAST AS SPC HAS
ISSUED SEVERE TSTM WATCH TIL 9PM. MAX TEMPS HAVE LIKELY BEEN
REACHED IN MOST PLACES AS TSTMS ARE DEVELOPING RAPIDLY. SOME
RECORD HIGHS NEARED OR EXCEEDED...SEE CLIMATE SECTION BELOW.
OTHERWISE...A SLOW MOVING COLD FRONT FROM THE NORTH WILL MOVE INTO
THE REGION THIS AFTERNOON. WITH THE REGION BEING ON THE NE EDGE OF
A VERY HOT AIR MASS...DAY STARTS OUT VERY WARM AND LARGE CAPE IN
THE 2000 TO 4000 J/KG RANGE IS EXPECTED TO BUILD WITH DIURNAL
WARMING. SHEAR OF 30 KT 0-6KM WITH WET BULB ZERO HEIGHTS OF 13-14
KFT. MENTIONED GUSTY WINDS AND SMALL HAIL WITH SOME CELLS HAVING A
SLIGHT CHANCE OF GOING SEVERE.
BEFORE COVERAGE OF SHOWERS AND THUNDERSTORMS BECOMES
WIDESPREAD...AT LEAST SOUTHERN PORTIONS OF THE REGION WILL SEE
ENOUGH SUN TO HAVE HIGHS WELL INTO THE 90S AND WITH VERY MOIST
AIR MASS CONVEYED BY PWATS NEAR 2 INCHES AND DEWPOINTS IN THE LOWER
70S...HEAT INDICES ARE EXPECTED TO BE NEAR 100 DEGREES FOR NEW
YORK CITY AS WELL AS URBAN SECTIONS OF SOUTHERN WESTCHESTER...MOST
OF NE NJ AND WESTERN LONG ISLAND.
FARTHER UP NORTH IN LOWER HUDSON VALLEY AND SOUTHERN CT WILL DEPEND
ON HOW FAST CONVECTION DEVELOPS AND THE INHERENT MITIGATION OF
DIURNAL WARMTH ASSOCIATED WITH EXPANDING CIRRUS CLOUD SHIELD OF
CONVECTION. RIGHT NOW...KEPT THEM LOWER WITHOUT HEAT ADVISORY BUT
HEAT INDICES ARE EXPECTED TO REACH MID TO UPPER 90S BEFORE
CONVECTION INCREASES SUBSTANTIALLY IN COVERAGE THIS AFTERNOON.
WILL START OFF THE HEAT ADVISORY LATE THIS MORNING BY 10 AM SINCE WE
WILL BE COMMENCING THE DIURNAL PERIOD AT A MUCH WARMER TEMPERATURE
THIS MORNING. MOST MODELS START TO BRING IN THE SHOWERS AND
THUNDERSTORMS BY 18Z ACROSS THE NORTHERN TIER AND BY 00Z ACROSS THE
ENTIRE AREA. ONLY EXCEPTION IS ECMWF WHICH HAS CONSISTENTLY HELD
BACK CONVECTION FOR LONG ISLAND UNTIL AFTER 00Z THU.
BASED ON MESOSCALE MODELS OF HRRR AND NSSL WRF...STRENGTHENING
CONVECTIVE CELLS START FIRING UP ALONG ACROSS THE ALLEGHENY PLATEAU
AND THE HUDSON VALLEY AROUND 17Z AFTER WHICH THEY WILL BE ON A
SOUTHEAST TRACK GOING INTO THE LOCAL FORECAST REGION. FURTHER
DEVELOPMENT OF CONVECTION COULD ALSO OCCUR FROM CONVERGENCE ALONG
THE SEA BREEZE BOUNDARY ESPECIALLY WITH ANY OUTFLOW BOUNDARIES FROM
CONVECTION MOVING IN FROM THE NORTH AND WEST. WIND SHEAR OF 25 TO 30
KT FROM 0-6 KM WILL ALLOW FOR SOME THUNDERSTORMS TO PRODUCE HAIL AND
GUSTY WINDS. PWATS NEAR 2 INCHES SO HEAVY RAIN ALSO CAN BE EXPECTED
WITH THUNDERSTORMS THAT FORM. THIS IS CONSIDERED ESPECIALLY SINCE
THE FLOW WILL BE NEARLY PARALLEL FROM LOW TO MID LEVELS WHICH WOULD
ALLOW FOR TRAINING OF CELLS. THE CONVECTIVE MODE LOOKS TO BE SQUALL
LINE TO BOW ECHOES.
THERE IS A MODERATE RISK FOR RIP CURRENTS TODAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/...
TONIGHT...RELATIVELY BETTER SHEAR ARRIVES WITH WINDS ALOFT AT 250MB
INCREASING AN EXTRA 10KT...PROMOTING GREATER DIVERGENCE. SOME
GREATER HEIGHT FALLS AT 500MB WILL ALSO IMPLY SOME GREATER SYNOPTIC
FORCING. THEREFORE EVEN THOUGH CAPE WILL BE ON A LOWERING
TREND...SOME THUNDERSTORMS WILL STILL MAINTAIN STRONG INTENSITIES
WITH HEAVY RAIN ALSO STILL POSSIBLE AS PWATS REMAIN NEAR 2 INCHES.
THE FRONT MOVES THROUGH LATE IN THE EVENING AND THEN SOUTH OF LONG
ISLAND GOING INTO THURSDAY. THE FRONT STALLS WITH A WEAK AREA OF LOW
PRESSURE MOVING IT. SOUTHERN PORTIONS OF THE FORECAST AREA COULD SEE
SOME LINGERING SHOWERS FROM TIME TO TIME ON THURSDAY AS A RESULT.
POPS ARE AT SLIGHT CHANCE WITH MODEL UNCERTAINTY DUE TO DIFFERENCES
IN QPF FIELDS AND RUN TO RUN INCONSISTENCY. IN THE UPPER LEVELS AT
500MB...THE AREA WILL BE IN A NW FLOW WITH A LONGWAVE TROUGH SETTING
UP ACROSS THE NORTHEAST. WENT WITH MORE OF THE COOLER GUIDANCE FOR
HIGHS CONSIDERING THE MORE EASTERLY FLOW. NOT EXPECTING ANY
THUNDERSTORMS WITH THIS ACTIVITY WITH MORE STABLE SFC CONDITIONS
FORECAST.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
A MEAN TROUGH WILL REMAIN OVER THE NE CONUS THROUGH THE PERIOD WHILE
A PERSISTENT AND STRONG RIDGE ALOFT REMAINS ENTRENCHED OVER THE
PLAINS AND ROCKIES.
COLD FRONT SLOWLY PRESSES SOUTHWARD THROUGH THE MID ATLANTIC STATES
THROUGH FRIDAY WITH CANADIAN HIGH PRES BUILDING IN FROM THE N. AN
AREA OF LOW PRES IS FORECAST TO DEVELOP ON THE FRONT THU NIGHT AND
PASS TO THE S FRI MORNING WITH AN UPPER LEVEL TROUGH SWINGING
THROUGH ALOFT. AN EASTERLY FLOW WILL MOISTEN LOW LEVELS WITH THE CHC
OF SHOWERS ON FRI. MODELS HAVE BEEN CONSISTENT WITH THIS FOR THE
LAST DAY...SO HAVE ADDED CHC POPS TO THE FORECAST. ABUNDANT CLOUD
COVER AND ONSHORE FLOW WILL RESULT IN A MUCH COOLER DAY ACROSS THE
AREA WITH HIGHS ONLY EXPECTED TO REACH THE UPPER 70S AT MOST
LOCATIONS. AS THE FRONT SINKS FURTHER S LATER FRI AND FRI NIGHT
DRIER AND MORE STABLE AIR WILL WORK IN FROM THE N AND E WITH DRY
WEATHER AND SEASONABLE THROUGH THE WEEKEND.
WAA ENSUES EARLY NEXT WEEK WITH H85 TEMPS RISING INTO THE UPPER
TEENS ON MON RESULTING IN TEMPS RISING A FEW DEGREES ABOVE NORMAL
LEVELS MON. PRE-FRONTAL TROUGH MAY TRIGGER ISOLD-SCT STORMS MON AFTN
AS COLD FRONT APPROACHES FROM THE NW. TYPICAL GFS IS FASTER THAN THE
EC WITH THE FROPA SO HAVE COMPROMISED THE TIMING WITH IT COMING
THROUGH TUE MORNING. DRY AND SEASONABLE WEATHER COURTESY OF HIGH
PRES THEN BUILDS BACK IN OVER THE AREA.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
A COLD FRONT WILL APPROACH THIS AFTERNOON...AND PASS TO THE SOUTH
TONIGHT.
MAINLY VFR OUTSIDE OF TSTMS...ALTHOUGH HZ IS RESTRICTING VSBY TO
5SM AT KGON. HYBRID SEA BREEZE/SW FLOW ACROSS COASTAL TERMINALS
THIS AFTERNOON. WINDS BECOMING NW AND WEAKENING IN WAKE OF COLD
FRONTAL PASSAGE LATE THIS EVENING/TONIGHT.
TSTM DEVELOPMENT THIS AFTERNOON/EVENING HAS SOME UNCERTAINTIES.
IT NOW APPEARS THAT THERE MAY BE MULTIPLE ROUNDS OF STORMS...ONE
EARLY THIS AFTERNOON AS STORMS DEVELOP INVOF A PRE-FRONTAL LOW
PRESSURE TROUGH ALREADY IN PLACE OVER THE REGION...THEN A SECOND
ROUND LATE IN THE DAY AS THE COLD FRONT ENTERS THE AREA. TSTM FCST
IN AMENDED TAF ADDRESSES ON THE FIRST ROUND...AND THE 18Z TAF
WILL BETTER ADDRESS THE SECOND ROUND AS CONFIDENCE LEVEL INCREASES
ONE WAY OR THE OTHER. THREAT OF STRONG WINDS AND CONVECTIVE
LLWS...HAIL AND HEAVY RAINFALL EXISTS WITH STRONGER CONVECTION.
CONVECTION EXPECTED TO TAPER AND WEAKEN THIS EVENING.
MAINLY VFR IN WAKE OF COLD FROPA...EXCEPT PATCHY GROUND FOG ACROSS
OUTLYING TERMINALS.
NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS
CAN BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KJFK FCSTER COMMENTS: MODERATE CONFIDENCE ON CONVECTION OCCURRING
AT SOME POINT DURING THE AFTERNOON...BUT LOW CONFIDENCE IN EXACT
TIMING IN THE TAFS. ISOLATED CONVECTION POSSIBLE AS EARLY AS 16Z.
HYBRID SEA BREEZE/SW FLOW THIS AFTERNOON.
KLGA FCSTER COMMENTS: MODERATE CONFIDENCE ON CONVECTION OCCURRING
AT SOME POINT DURING THE AFTERNOON...BUT LOW CONFIDENCE IN EXACT
TIMING IN THE TAFS. ISOLATED CONVECTION POSSIBLE AS EARLY AS 16Z.
KEWR FCSTER COMMENTS: MODERATE CONFIDENCE ON CONVECTION OCCURRING
AT SOME POINT DURING THE AFTERNOON...BUT LOW CONFIDENCE IN EXACT
TIMING IN THE TAFS. ISOLATED CONVECTION POSSIBLE AS EARLY AS 16Z.
THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH
IMPLIES SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD.
KTEB FCSTER COMMENTS: MODERATE CONFIDENCE ON CONVECTION OCCURRING
AT SOME POINT DURING THE AFTERNOON...BUT LOW CONFIDENCE IN EXACT
TIMING IN THE TAFS. ISOLATED CONVECTION POSSIBLE AS EARLY AS 16Z.
OCCASIONAL GUSTS POSSIBLE FROM LATE MORNING THROUGH THE AFTERNOON.
KHPN FCSTER COMMENTS: MODERATE CONFIDENCE ON CONVECTION OCCURRING
AT SOME POINT DURING THE AFTERNOON...BUT LOW CONFIDENCE IN EXACT
TIMING IN THE TAFS. ISOLATED CONVECTION POSSIBLE AS EARLY AS 16Z.
OCCASIONAL GUSTS POSSIBLE FROM LATE MORNING THROUGH THE AFTERNOON.
KISP FCSTER COMMENTS: MODERATE CONFIDENCE ON CONVECTION OCCURRING
AT SOME POINT DURING THE AFTERNOON...BUT LOW CONFIDENCE IN EXACT
TIMING IN THE TAFS. ISOLATED CONVECTION POSSIBLE AS EARLY AS 17Z.
HYBRID SEA BREEZE/SW FLOW THIS AFTERNOON.
OUTLOOK FOR 12Z THU THROUGH SUN...
.THU-THU EVENING...VFR. SCT SHOWERS POSSIBLE.
.LATE THU NIGHT-SAT MORNING...MVFR CIGS POSSIBLE...BEST CHANCE AT
SOUTHERN/COASTAL TERMINALS.
.SAT AFTERNOON-SUN...VFR.
&&
.MARINE...
MARGINAL SCA CONDITIONS ARE POSSIBLE AT TIMES ACROSS OUTER OCEAN
WATERS IN THE SHORT TERM THROUGH THURSDAY NIGHT. HOWEVER...KEPT
OCEAN SEAS BELOW 5 FT SINCE WAVEWATCH INITIALLY ABOUT A FOOT TOO
HIGH COMPARED TO OBS.
MARGINAL SCA CONDS ARE POSSIBLE ON THE OCEAN WATERS FRI/FRI NIGHT
WITH AN INCREASING EASTERLY FLOW BETWEEN HIGH PRES BUILDING IN FROM
THE N AND LOW PRES PASSING TO THE S. A RELATIVELY LIGHT SE-S FLOW
WILL THEN PREVAIL WITH SUB-ADVY CONDS THEREAFTER. HAVE CUT A FT OFF
OF WAVEWATCH GUIDANCE THROUGH THE PERIOD AS IT CONTINUES TO RUN
HIGH.
&&
.HYDROLOGY...
NO PRECIPITATION IS EXPECTED INTO THIS MORNING.
FLASH FLOODING IS POSSIBLE WITH ANY TRAINING CONVECTION THIS
AFTERNOON AND EVENING AS PWATS INCREASE TO AROUND 2 INCHES AND
STEERING FLOW NEARLY ALIGNS WITH FRONTAL BOUNDARY. A BASIN AVERAGE
QPF OF AROUND 1/4 TO 1/2 INCH IS POSSIBLE ACROSS THE AREA...WITH
LOCALIZED AMOUNTS IN EXCESS OF 2 INCHES POSSIBLE WITH ANY TRAINING
CONVECTION.
&&
.CLIMATE...
NEWARK HAS BROKEN THEIR RECORD HIGH TODAY WITH A MAX OF 103 DEGREES SO
FAR. LA GUARDIA ARPT HAS HIT 100 DEGREES...WHICH TIES THEIR RECORD.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...HEAT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR CTZ005>010.
NY...HEAT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR NYZ067>075-
078>081-176>179.
NJ...HEAT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR NJZ002-004-006-
103>108.
MARINE...NONE.
&&
$$
SYNOPSIS...JM
NEAR TERM...GS
SHORT TERM...JM LONG TERM...24
AVIATION...GOODMAN/NV
MARINE...24/JM
HYDROLOGY...24/JM
CLIMATE...TM/GS
AREA FORECAST DISCUSSION
NWS NEW YORK NY
1103 AM EDT WED JUL 18 2012
.SYNOPSIS...
A SLOW MOVING COLD FRONT FROM THE NORTH WILL MOVE INTO THE REGION
THIS AFTERNOON AND SOUTH OF THE REGION LATE TONIGHT INTO THURSDAY.
THE FRONT WILL THEN STALL WITH A WEAK AREA OF LOW PRESSURE MOVING
ALONG IT. LOW PRESSURE PASSES TO THE SOUTH ON FRIDAY WITH HIGH
PRESSURE BUILDING IN FROM THE NORTH THROUGH THE WEEKEND. ANOTHER
COLD FRONT WILL TRACK ACROSS THE AREA ON TUESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
MADE SOME MINOR UPDATES TO THE GRIDS THIS MORNING TO INCREASE
CLOUD COVER AND ADD SLGT CHC POPS FOR A FEW SHRA THAT HAVE
DEVELOPED WITHIN ZONE OF ENHANCED MID LEVEL LIFT ACROSS CT/LI.
THIS SHOULD MOVE OFF TO THE E WITH A FEW HRS OF SUNSHINE EXPECTED.
ONLY OTHER CHANGE TO THE FORECAST WAS TO INCREASE MAX TEMPS ACROSS
LI BY 1-2 DEGREES. MAX TEMPS REALLY CLIMBING FAST...AND ARE
ALREADY WITHIN A FEW DEGREES OF MAX TEMPS ELSEWHERE SO THESE MAY
NEED TO BE ADJUSTED UPWARD. LOOKS LIKE AN ACTIVE AFTERNOON WITH CAP
RAPIDLY ERODING. AREA REMAINS IN A SLIGHT RISK FROM SPC. SEE BELOW
FOR DETAILS ON WHAT IS EXPECTED.
OTHERWISE...A SLOW MOVING COLD FRONT FROM THE NORTH WILL MOVE INTO
THE REGION THIS AFTERNOON. WITH THE REGION BEING ON THE NE EDGE OF
A VERY HOT AIR MASS...DAY STARTS OUT VERY WARM AND LARGE CAPE IN
THE 2000 TO 4000 J/KG RANGE IS EXPECTED TO BUILD WITH DIURNAL
WARMING. SHEAR OF 30 KT 0-6KM WITH WET BULB ZERO HEIGHTS OF 13-14
KFT. MENTIONED GUSTY WINDS AND SMALL HAIL WITH SOME CELLS HAVING A
SLIGHT CHANCE OF GOING SEVERE.
BEFORE COVERAGE OF SHOWERS AND THUNDERSTORMS BECOMES
WIDESPREAD...AT LEAST SOUTHERN PORTIONS OF THE REGION WILL SEE
ENOUGH SUN TO HAVE HIGHS WELL INTO THE 90S AND WITH VERY MOIST
AIR MASS CONVEYED BY PWATS NEAR 2 INCHES AND DEWPOINTS IN THE LOWER
70S...HEAT INDICES ARE EXPECTED TO BE NEAR 100 DEGREES FOR NEW
YORK CITY AS WELL AS URBAN SECTIONS OF SOUTHERN WESTCHESTER...MOST
OF NE NJ AND WESTERN LONG ISLAND.
FARTHER UP NORTH IN LOWER HUDSON VALLEY AND SOUTHERN CT WILL DEPEND
ON HOW FAST CONVECTION DEVELOPS AND THE INHERENT MITIGATION OF
DIURNAL WARMTH ASSOCIATED WITH EXPANDING CIRRUS CLOUD SHIELD OF
CONVECTION. RIGHT NOW...KEPT THEM LOWER WITHOUT HEAT ADVISORY BUT
HEAT INDICES ARE EXPECTED TO REACH MID TO UPPER 90S BEFORE
CONVECTION INCREASES SUBSTANTIALLY IN COVERAGE THIS AFTERNOON.
WILL START OFF THE HEAT ADVISORY LATE THIS MORNING BY 10 AM SINCE WE
WILL BE COMMENCING THE DIURNAL PERIOD AT A MUCH WARMER TEMPERATURE
THIS MORNING. MOST MODELS START TO BRING IN THE SHOWERS AND
THUNDERSTORMS BY 18Z ACROSS THE NORTHERN TIER AND BY 00Z ACROSS THE
ENTIRE AREA. ONLY EXCEPTION IS ECMWF WHICH HAS CONSISTENTLY HELD
BACK CONVECTION FOR LONG ISLAND UNTIL AFTER 00Z THU.
BASED ON MESOSCALE MODELS OF HRRR AND NSSL WRF...STRENGTHENING
CONVECTIVE CELLS START FIRING UP ALONG ACROSS THE ALLEGHENY PLATEAU
AND THE HUDSON VALLEY AROUND 17Z AFTER WHICH THEY WILL BE ON A
SOUTHEAST TRACK GOING INTO THE LOCAL FORECAST REGION. FURTHER
DEVELOPMENT OF CONVECTION COULD ALSO OCCUR FROM CONVERGENCE ALONG
THE SEA BREEZE BOUNDARY ESPECIALLY WITH ANY OUTFLOW BOUNDARIES FROM
CONVECTION MOVING IN FROM THE NORTH AND WEST. WIND SHEAR OF 25 TO 30
KT FROM 0-6 KM WILL ALLOW FOR SOME THUNDERSTORMS TO PRODUCE HAIL AND
GUSTY WINDS. PWATS NEAR 2 INCHES SO HEAVY RAIN ALSO CAN BE EXPECTED
WITH THUNDERSTORMS THAT FORM. THIS IS CONSIDERED ESPECIALLY SINCE
THE FLOW WILL BE NEARLY PARALLEL FROM LOW TO MID LEVELS WHICH WOULD
ALLOW FOR TRAINING OF CELLS. THE CONVECTIVE MODE LOOKS TO BE SQUALL
LINE TO BOW ECHOES.
THERE IS A MODERATE RISK FOR RIP CURRENTS TODAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/...
TONIGHT...RELATIVELY BETTER SHEAR ARRIVES WITH WINDS ALOFT AT 250MB
INCREASING AN EXTRA 10KT...PROMOTING GREATER DIVERGENCE. SOME
GREATER HEIGHT FALLS AT 500MB WILL ALSO IMPLY SOME GREATER SYNOPTIC
FORCING. THEREFORE EVEN THOUGH CAPE WILL BE ON A LOWERING
TREND...SOME THUNDERSTORMS WILL STILL MAINTAIN STRONG INTENSITIES
WITH HEAVY RAIN ALSO STILL POSSIBLE AS PWATS REMAIN NEAR 2 INCHES.
THE FRONT MOVES THROUGH LATE IN THE EVENING AND THEN SOUTH OF LONG
ISLAND GOING INTO THURSDAY. THE FRONT STALLS WITH A WEAK AREA OF LOW
PRESSURE MOVING IT. SOUTHERN PORTIONS OF THE FORECAST AREA COULD SEE
SOME LINGERING SHOWERS FROM TIME TO TIME ON THURSDAY AS A RESULT.
POPS ARE AT SLIGHT CHANCE WITH MODEL UNCERTAINTY DUE TO DIFFERENCES
IN QPF FIELDS AND RUN TO RUN INCONSISTENCY. IN THE UPPER LEVELS AT
500MB...THE AREA WILL BE IN A NW FLOW WITH A LONGWAVE TROUGH SETTING
UP ACROSS THE NORTHEAST. WENT WITH MORE OF THE COOLER GUIDANCE FOR
HIGHS CONSIDERING THE MORE EASTERLY FLOW. NOT EXPECTING ANY
THUNDERSTORMS WITH THIS ACTIVITY WITH MORE STABLE SFC CONDITIONS
FORECAST.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
A MEAN TROUGH WILL REMAIN OVER THE NE CONUS THROUGH THE PERIOD WHILE
A PERSISTENT AND STRONG RIDGE ALOFT REMAINS ENTRENCHED OVER THE
PLAINS AND ROCKIES.
COLD FRONT SLOWLY PRESSES SOUTHWARD THROUGH THE MID ATLANTIC STATES
THROUGH FRIDAY WITH CANADIAN HIGH PRES BUILDING IN FROM THE N. AN
AREA OF LOW PRES IS FORECAST TO DEVELOP ON THE FRONT THU NIGHT AND
PASS TO THE S FRI MORNING WITH AN UPPER LEVEL TROUGH SWINGING
THROUGH ALOFT. AN EASTERLY FLOW WILL MOISTEN LOW LEVELS WITH THE CHC
OF SHOWERS ON FRI. MODELS HAVE BEEN CONSISTENT WITH THIS FOR THE
LAST DAY...SO HAVE ADDED CHC POPS TO THE FORECAST. ABUNDANT CLOUD
COVER AND ONSHORE FLOW WILL RESULT IN A MUCH COOLER DAY ACROSS THE
AREA WITH HIGHS ONLY EXPECTED TO REACH THE UPPER 70S AT MOST
LOCATIONS. AS THE FRONT SINKS FURTHER S LATER FRI AND FRI NIGHT
DRIER AND MORE STABLE AIR WILL WORK IN FROM THE N AND E WITH DRY
WEATHER AND SEASONABLE THROUGH THE WEEKEND.
WAA ENSUES EARLY NEXT WEEK WITH H85 TEMPS RISING INTO THE UPPER
TEENS ON MON RESULTING IN TEMPS RISING A FEW DEGREES ABOVE NORMAL
LEVELS MON. PRE-FRONTAL TROUGH MAY TRIGGER ISOLD-SCT STORMS MON AFTN
AS COLD FRONT APPROACHES FROM THE NW. TYPICAL GFS IS FASTER THAN THE
EC WITH THE FROPA SO HAVE COMPROMISED THE TIMING WITH IT COMING
THROUGH TUE MORNING. DRY AND SEASONABLE WEATHER COURTESY OF HIGH
PRES THEN BUILDS BACK IN OVER THE AREA.
&&
.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
A COLD FRONT WILL APPROACH THIS AFTERNOON...AND PASS TO THE SOUTH
TONIGHT.
MAINLY VFR OUTSIDE OF TSTMS...ALTHOUGH HZ IS RESTRICTING VSBY TO
5SM AT KGON. HYBRID SEA BREEZE/SW FLOW ACROSS COASTAL TERMINALS
THIS AFTERNOON. WINDS BECOMING NW AND WEAKENING IN WAKE OF COLD
FRONTAL PASSAGE LATE THIS EVENING/TONIGHT.
TSTM DEVELOPMENT THIS AFTERNOON/EVENING HAS SOME UNCERTAINTIES.
IT NOW APPEARS THAT THERE MAY BE MULTIPLE ROUNDS OF STORMS...ONE
EARLY THIS AFTERNOON AS STORMS DEVELOP INVOF A PRE-FRONTAL LOW
PRESSURE TROUGH ALREADY IN PLACE OVER THE REGION...THEN A SECOND
ROUND LATE IN THE DAY AS THE COLD FRONT ENTERS THE AREA. TSTM FCST
IN AMENDED TAF ADDRESSES ON THE FIRST ROUND...AND THE 18Z TAF
WILL BETTER ADDRESS THE SECOND ROUND AS CONFIDENCE LEVEL INCREASES
ONE WAY OR THE OTHER. THREAT OF STRONG WINDS AND CONVECTIVE
LLWS...HAIL AND HEAVY RAINFALL EXISTS WITH STRONGER CONVECTION.
CONVECTION EXPECTED TO TAPER AND WEAKEN THIS EVENING.
MAINLY VFR IN WAKE OF COLD FROPA...EXCEPT PATCHY GROUND FOG ACROSS
OUTLYING TERMINALS.
...NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS
CAN BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KJFK FCSTER COMMENTS: MODERATE CONFIDENCE ON CONVECTION OCCURRING
AT SOME POINT DURING THE AFTERNOON...BUT LOW CONFIDENCE IN EXACT
TIMING IN THE TAFS. ISOLATED CONVECTION POSSIBLE AS EARLY AS 16Z.
HYBRID SEA BREEZE/SW FLOW THIS AFTERNOON.
KLGA FCSTER COMMENTS: MODERATE CONFIDENCE ON CONVECTION OCCURRING
AT SOME POINT DURING THE AFTERNOON...BUT LOW CONFIDENCE IN EXACT
TIMING IN THE TAFS. ISOLATED CONVECTION POSSIBLE AS EARLY AS 16Z.
KEWR FCSTER COMMENTS: MODERATE CONFIDENCE ON CONVECTION OCCURRING
AT SOME POINT DURING THE AFTERNOON...BUT LOW CONFIDENCE IN EXACT
TIMING IN THE TAFS. ISOLATED CONVECTION POSSIBLE AS EARLY AS 16Z.
THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH
IMPLIES SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD.
KTEB FCSTER COMMENTS: MODERATE CONFIDENCE ON CONVECTION OCCURRING
AT SOME POINT DURING THE AFTERNOON...BUT LOW CONFIDENCE IN EXACT
TIMING IN THE TAFS. ISOLATED CONVECTION POSSIBLE AS EARLY AS 16Z.
OCCASIONAL GUSTS POSSIBLE FROM LATE MORNING THROUGH THE AFTERNOON.
KHPN FCSTER COMMENTS: MODERATE CONFIDENCE ON CONVECTION OCCURRING
AT SOME POINT DURING THE AFTERNOON...BUT LOW CONFIDENCE IN EXACT
TIMING IN THE TAFS. ISOLATED CONVECTION POSSIBLE AS EARLY AS 16Z.
OCCASIONAL GUSTS POSSIBLE FROM LATE MORNING THROUGH THE AFTERNOON.
KISP FCSTER COMMENTS: MODERATE CONFIDENCE ON CONVECTION OCCURRING
AT SOME POINT DURING THE AFTERNOON...BUT LOW CONFIDENCE IN EXACT
TIMING IN THE TAFS. ISOLATED CONVECTION POSSIBLE AS EARLY AS 17Z.
HYBRID SEA BREEZE/SW FLOW THIS AFTERNOON.
OUTLOOK FOR 12Z THU THROUGH SUN...
.THU-THU EVENING...VFR. SCT SHOWERS POSSIBLE.
.LATE THU NIGHT-SAT MORNING...MVFR CIGS POSSIBLE...BEST CHANCE AT
SOUTHERN/COASTAL TERMINALS.
.SAT AFTERNOON-SUN...VFR.
&&
.MARINE...
MARGINAL SCA CONDITIONS ARE POSSIBLE AT TIMES ACROSS OUTER OCEAN
WATERS IN THE SHORT TERM THROUGH THURSDAY NIGHT. HOWEVER...KEPT
OCEAN SEAS BELOW 5 FT SINCE WAVEWATCH INITIALLY ABOUT A FOOT TOO
HIGH COMPARED TO OBS.
MARGINAL SCA CONDS ARE POSSIBLE ON THE OCEAN WATERS FRI/FRI NIGHT
WITH AN INCREASING EASTERLY FLOW BETWEEN HIGH PRES BUILDING IN FROM
THE N AND LOW PRES PASSING TO THE S. A RELATIVELY LIGHT SE-S FLOW
WILL THEN PREVAIL WITH SUB-ADVY CONDS THEREAFTER. HAVE CUT A FT OFF
OF WAVEWATCH GUIDANCE THROUGH THE PERIOD AS IT CONTINUES TO RUN
HIGH.
&&
.HYDROLOGY...
NO PRECIPITATION IS EXPECTED INTO THIS MORNING.
FLASH FLOODING IS POSSIBLE WITH ANY TRAINING CONVECTION THIS
AFTERNOON AND EVENING AS PWATS INCREASE TO AROUND 2 INCHES AND
STEERING FLOW NEARLY ALIGNS WITH FRONTAL BOUNDARY. A BASIN AVERAGE
QPF OF AROUND 1/4 TO 1/2 INCH IS POSSIBLE ACROSS THE AREA...WITH
LOCALIZED AMOUNTS IN EXCESS OF 2 INCHES POSSIBLE WITH ANY TRAINING
CONVECTION.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...HEAT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR NYZ071>075-078-
080-176>179.
NJ...HEAT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR NJZ004-006-
103>108.
MARINE...NONE.
&&
$$
SYNOPSIS...JM
NEAR TERM...GS/JM
SHORT TERM...JM
LONG TERM...24
AVIATION...GOODMAN/NV
MARINE...24/JM
HYDROLOGY...24/JM
AREA FORECAST DISCUSSION
NWS NEW YORK NY
741 AM EDT WED JUL 18 2012
.SYNOPSIS...
A SLOW MOVING COLD FRONT FROM THE NORTH WILL MOVE INTO THE REGION
THIS AFTERNOON AND SOUTH OF THE REGION LATE TONIGHT INTO THURSDAY.
THE FRONT WILL THEN STALL WITH A WEAK AREA OF LOW PRESSURE MOVING
ALONG IT. LOW PRESSURE PASSES TO THE SOUTH ON FRIDAY WITH HIGH
PRESSURE BUILDING IN FROM THE NORTH THROUGH THE WEEKEND. ANOTHER
COLD FRONT WILL TRACK ACROSS THE AREA ON TUESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
FORECAST GENERALLY ON TRACK WITH JUST SLIGHT DOWNWARD ADJUSTMENTS
WITH SOME TEMPS EARLY THIS MORNING AND CLOUD COVERAGE. DRY WEATHER
EXPECTED WITH RELATIVELY WARM CONDITIONS THIS MORNING.
A SLOW MOVING COLD FRONT FROM THE NORTH WILL MOVE INTO THE REGION
THIS AFTERNOON. WITH THE REGION BEING ON THE NE EDGE OF A VERY HOT
AIRMASS...DAY STARTS OUT VERY WARM AND LARGE CAPE IN THE 2000 TO
4000 J/KG RANGE IS EXPECTED TO BUILD WITH DIURNAL WARMING. SHEAR
OF 30 KT 0-6KM WITH WETBULB ZERO HEIGHTS OF 13-14 KFT. MENTIONED
GUSTY WINDS AND SMALL HAIL WITH SOME CELLS HAVING A SLIGHT CHANCE
OF GOING SEVERE.
BEFORE COVERAGE OF SHOWERS AND THUNDERSTORMS BECOMES
WIDESPREAD...AT LEAST SOUTHERN PORTIONS OF THE REGION WILL SEE
ENOUGH SUN TO HAVE HIGHS WELL INTO THE 90S AND WITH VERY MOIST
AIRMASS CONVEYED BY PWATS NEAR 2 INCHES AND DEWPOINTS IN THE LOWER
70S...HEAT INDICES ARE EXPECTED TO BE NEAR 100 DEGREES FOR NEW
YORK CITY AS WELL AS URBAN SECTIONS OF SOUTHERN WESTCHESTER...MOST
OF NE NJ AND WESTERN LONG ISLAND.
FARTHER UP NORTH IN LOWER HUDSON VALLEY AND SOUTHERN CT WILL DEPEND
ON HOW FAST CONVECTION DEVELOPS AND THE INHERENT MITIGATION OF
DIURNAL WARMTH ASSOCIATED WITH EXPANDING CIRRUS CLOUD SHIELD OF
CONVECTION. RIGHT NOW...KEPT THEM LOWER WITHOUT HEAT ADVISORY BUT
HEAT INDICES ARE EXPECTED TO REACH MID TO UPPER 90S BEFORE
CONVECTION INCREASES SUBSTANTIALLY IN COVERAGE THIS AFTERNOON.
WILL START OFF THE HEAT ADVISORY LATE THIS MORNING BY 10 AM SINCE WE
WILL BE COMMENCING THE DIURNAL PERIOD AT A MUCH WARMER TEMPERATURE
THIS MORNING. MOST MODELS START TO BRING IN THE SHOWERS AND
THUNDERSTORMS BY 18Z ACROSS THE NORTHERN TIER AND BY 00Z ACROSS THE
ENTIRE AREA. ONLY EXCEPTION IS ECMWF WHICH HAS CONSISTENTLY HELD
BACK CONVECTION FOR LONG ISLAND UNTIL AFTER 00Z THU.
BASED ON MESOSCALE MODELS OF HRRR AND NSSL WRF...STRENGTHENING
CONVECTIVE CELLS START FIRING UP ALONG ACROSS THE ALLEGHENY PLATEAU
AND THE HUDSON VALLEY AROUND 17Z AFTER WHICH THEY WILL BE ON A
SOUTHEAST TRACK GOING INTO THE LOCAL FORECAST REGION. FURTHER
DEVELOPMENT OF CONVECTION COULD ALSO OCCUR FROM CONVERGENCE ALONG
THE SEA BREEZE BOUNDARY ESPECIALLY WITH ANY OUTFLOW BOUNDARIES FROM
CONVECTION MOVING IN FROM THE NORTH AND WEST. WIND SHEAR OF 25 TO 30
KT FROM 0-6 KM WILL ALLOW FOR SOME THUNDERSTORMS TO PRODUCE HAIL AND
GUSTY WINDS. PWATS NEAR 2 INCHES SO HEAVY RAIN ALSO CAN BE EXPECTED
WITH THUNDERSTORMS THAT FORM. THIS IS CONSIDERED ESPECIALLY SINCE
THE FLOW WILL BE NEARLY PARALLEL FROM LOW TO MID LEVELS WHICH WOULD
ALLOW FOR TRAINING OF CELLS. THE CONVECTIVE MODE LOOKS TO BE SQUALL
LINE TO BOW ECHOES.
THERE IS A MODERATE RISK FOR RIP CURRENTS TODAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/...
TONIGHT...RELATIVELY BETTER SHEAR ARRIVES WITH WINDS ALOFT AT 250MB
INCREASING AN EXTRA 10KT...PROMOTING GREATER DIVERGENCE. SOME
GREATER HEIGHT FALLS AT 500MB WILL ALSO IMPLY SOME GREATER SYNOPTIC
FORCING. THEREFORE EVEN THOUGH CAPE WILL BE ON A LOWERING
TREND...SOME THUNDERSTORMS WILL STILL MAINTAIN STRONG INTENSITIES
WITH HEAVY RAIN ALSO STILL POSSIBLE AS PWATS REMAIN NEAR 2 INCHES.
THE FRONT MOVES THROUGH LATE IN THE EVENING AND THEN SOUTH OF LONG
ISLAND GOING INTO THURSDAY. THE FRONT STALLS WITH A WEAK AREA OF LOW
PRESSURE MOVING IT. SOUTHERN PORTIONS OF THE FORECAST AREA COULD SEE
SOME LINGERING SHOWERS FROM TIME TO TIME ON THURSDAY AS A RESULT.
POPS ARE AT SLIGHT CHANCE WITH MODEL UNCERTAINTY DUE TO DIFFERENCES
IN QPF FIELDS AND RUN TO RUN INCONSISTENCY. IN THE UPPER LEVELS AT
500MB...THE AREA WILL BE IN A NW FLOW WITH A LONGWAVE TROUGH SETTING
UP ACROSS THE NORTHEAST. WENT WITH MORE OF THE COOLER GUIDANCE FOR
HIGHS CONSIDERING THE MORE EASTERLY FLOW. NOT EXPECTING ANY
THUNDERSTORMS WITH THIS ACTIVITY WITH MORE STABLE SFC CONDITIONS
FORECAST.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
A MEAN TROUGH WILL REMAIN OVER THE NE CONUS THROUGH THE PERIOD WHILE
A PERSISTENT AND STRONG RIDGE ALOFT REMAINS ENTRENCHED OVER THE
PLAINS AND ROCKIES.
COLD FRONT SLOWLY PRESSES SOUTHWARD THROUGH THE MID ATLANTIC STATES
THROUGH FRIDAY WITH CANADIAN HIGH PRES BUILDING IN FROM THE N. AN
AREA OF LOW PRES IS FORECAST TO DEVELOP ON THE FRONT THU NIGHT AND
PASS TO THE S FRI MORNING WITH AN UPPER LEVEL TROUGH SWINGING
THROUGH ALOFT. AN EASTERLY FLOW WILL MOISTEN LOW LEVELS WITH THE CHC
OF SHOWERS ON FRI. MODELS HAVE BEEN CONSISTENT WITH THIS FOR THE
LAST DAY...SO HAVE ADDED CHC POPS TO THE FORECAST. ABUNDANT CLOUD
COVER AND ONSHORE FLOW WILL RESULT IN A MUCH COOLER DAY ACROSS THE
AREA WITH HIGHS ONLY EXPECTED TO REACH THE UPPER 70S AT MOST
LOCATIONS. AS THE FRONT SINKS FURTHER S LATER FRI AND FRI NIGHT
DRIER AND MORE STABLE AIR WILL WORK IN FROM THE N AND E WITH DRY
WEATHER AND SEASONABLE THROUGH THE WEEKEND.
WAA ENSUES EARLY NEXT WEEK WITH H85 TEMPS RISING INTO THE UPPER
TEENS ON MON RESULTING IN TEMPS RISING A FEW DEGREES ABOVE NORMAL
LEVELS MON. PRE-FRONTAL TROUGH MAY TRIGGER ISOLD-SCT STORMS MON AFTN
AS COLD FRONT APPROACHES FROM THE NW. TYPICAL GFS IS FASTER THAN THE
EC WITH THE FROPA SO HAVE COMPROMISED THE TIMING WITH IT COMING
THROUGH TUE MORNING. DRY AND SEASONABLE WEATHER COURTESY OF HIGH
PRES THEN BUILDS BACK IN OVER THE AREA.
&&
.AVIATION /11Z WEDNESDAY THROUGH SUNDAY/...
A COLD FRONT MOVES INTO THE TERMINALS DURING THE AFTERNOON...MOVING
SOUTH THIS EVENING.
MAINLY VFR OUTSIDE OF TSTMS...ALTHOUGH HZ MAY RESTRICT VSBY TO
AROUND 6SM ACROSS COASTAL TERMINALS. OCCASIONAL GUSTY SW WINDS AT
NYC/NJ TERMINALS THIS MORNING THROUGH AFTERNOON. HYBRID
SEABREEZE/SW FLOW ACROSS COASTAL TERMINALS THIS
AFTERNOON. WINDS BECOMING NW AND WEAKENING IN WAKE OF COLD FRONTAL
PASSAGE LATE THIS EVENING/TONIGHT.
CONVECTION DEVELOPMENT IN COSPA APPEARS TO BE A BIT TOO SLOW. CCFP
LOOKS REASONABLE THROUGH 17Z WITH EXPECTATION FOR ISOLATED TSTMS
COVERAGE FROM LATE MORNING THROUGH 17Z. THEN THUNDERSTORM
COVERAGE EXPECTED TO INCREASE TO NUMEROUS THROUGH THE AFTERNOON
AND INTO THE EARLY EVENING. THREAT OF GUSTY WINDS...HAIL AND HEAVY
RAINFALL EXISTS WITH STRONGER CONVECTION. CONVECTION EXPECTED TO
TAPER AND WEAKEN DURING THROUGH THE EVENING HOURS.
MAINLY VFR IN WAKE OF COLD FRONTAL PASSAGE...EXCEPT PATCHY GROUND
FOG ACROSS OUTLYING TERMINALS.
NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS
CAN BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KJFK FCSTER COMMENTS: MODERATE CONFIDENCE ON CONVECTION OCCURRING
AT SOME POINT DURING THE AFTERNOON...BUT LOW CONFIDENCE IN EXACT
TIMING IN THE TAFS. ISOLATED CONVECTION POSSIBLE AS EARLY AS 16Z.
HYBRID SEABREEZE/SW FLOW THIS AFTERNOON.
KLGA FCSTER COMMENTS: MODERATE CONFIDENCE ON CONVECTION OCCURRING
AT SOME POINT DURING THE AFTERNOON...BUT LOW CONFIDENCE IN EXACT
TIMING IN THE TAFS. ISOLATED CONVECTION POSSIBLE AS EARLY AS 16Z.
KEWR FCSTER COMMENTS: MODERATE CONFIDENCE ON CONVECTION OCCURRING
AT SOME POINT DURING THE AFTERNOON...BUT LOW CONFIDENCE IN EXACT
TIMING IN THE TAFS. ISOLATED CONVECTION POSSIBLE AS EARLY AS 16Z.
THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH
IMPLIES SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD.
KTEB FCSTER COMMENTS: MODERATE CONFIDENCE ON CONVECTION OCCURRING
AT SOME POINT DURING THE AFTERNOON...BUT LOW CONFIDENCE IN EXACT
TIMING IN THE TAFS. ISOLATED CONVECTION POSSIBLE AS EARLY AS 16Z.
OCCASIONAL GUSTS POSSIBLE FROM LATE MORNING THROUGH THE AFTERNOON.
KHPN FCSTER COMMENTS: MODERATE CONFIDENCE ON CONVECTION OCCURRING
AT SOME POINT DURING THE AFTERNOON...BUT LOW CONFIDENCE IN EXACT
TIMING IN THE TAFS. ISOLATED CONVECTION POSSIBLE AS EARLY AS 16Z.
OCCASIONAL GUSTS POSSIBLE FROM LATE MORNING THROUGH THE AFTERNOON.
KISP FCSTER COMMENTS: MODERATE CONFIDENCE ON CONVECTION OCCURRING
AT SOME POINT DURING THE AFTERNOON...BUT LOW CONFIDENCE IN EXACT
TIMING IN THE TAFS. ISOLATED CONVECTION POSSIBLE AS EARLY AS 16Z.
HYBRID SEABREEZE/SW FLOW THIS AFTERNOON.
OUTLOOK FOR 12Z THURSDAY THROUGH SUNDAY...
.THURSDAY-THURSDAY EVENING...VFR. SCATTERED SHOWERS POSSIBLE.
.LATE THURSDAY NIGHT-SATURDAY MORNING...CEILINGS 1500 FT TO 2500 FT
POSSIBLE...BEST CHANCE AT SOUTHERN/COASTAL TERMINALS.
.SATURDAY AFTERNOON-SUNDAY...VFR.
&&
.MARINE...
MARGINAL SCA CONDITIONS ARE POSSIBLE AT TIMES ACROSS OUTER OCEAN
WATERS IN THE SHORT TERM THROUGH THURSDAY NIGHT. HOWEVER...KEPT
OCEAN SEAS BELOW 5 FT SINCE WAVEWATCH INITIALLY ABOUT A FOOT TOO
HIGH COMPARED TO OBS.
MARGINAL SCA CONDS ARE POSSIBLE ON THE OCEAN WATERS FRI/FRI NIGHT
WITH AN INCREASING EASTERLY FLOW BETWEEN HIGH PRES BUILDING IN FROM
THE N AND LOW PRES PASSING TO THE S. A RELATIVELY LIGHT SE-S FLOW
WILL THEN PREVAIL WITH SUB-ADVSY CONDS THEREAFTER. HAVE CUT A FT OFF
OF WAVEWATCH GUIDANCE THROUGH THE PERIOD AS IT CONTINUES TO RUN
HIGH.
&&
.HYDROLOGY...
NO PRECIPITATION IS EXPECTED INTO THIS MORNING.
FLASH FLOODING IS POSSIBLE WITH ANY TRAINING CONVECTION THIS
AFTERNOON AND EVENING AS PWATS INCREASE TO AROUND 2 INCHES AND
STEERING FLOW NEARLY ALIGNS WITH FRONTAL BOUNDARY. A BASIN AVERAGE
QPF OF AROUND 1/4 TO 1/2 INCH IS POSSIBLE ACROSS THE AREA...WITH
LOCALIZED AMOUNTS IN EXCESS OF 2 INCHES POSSIBLE WITH ANY TRAINING
CONVECTION.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...HEAT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR NYZ072>075-176-
178.
HEAT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR NYZ071-078-080-
177-179.
NJ... HEAT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR NJZ004-006-
103>108.
MARINE...NONE.
&&
$$
SYNOPSIS...JM
NEAR TERM...JM
SHORT TERM...JM
LONG TERM...24
AVIATION...NV
MARINE...24/JM
HYDROLOGY...24/JM
AREA FORECAST DISCUSSION
NWS ALBANY NY
658 AM EDT WED JUL 18 2012
.SYNOPSIS...
A COLD FRONT WILL SLOWLY MOVE SOUTHWARD ACROSS EASTERN NEW YORK AND
WESTERN NEW ENGLAND TODAY WITH SOME SHOWERS AND THUNDERSTORMS. A
BROAD AREA OF HIGH PRESSURE WILL BUILD IN FROM JAMES BAY TONIGHT
INTO THURSDAY WITH SEASONABLE TEMPERATURES AND LESS HUMID
CONDITIONS. A DISTURBANCE MOVING ALONG THE OLD FRONTAL BOUNDARY
OVER THE UPPER MID ATLANTIC REGION MAY BRING A FEW SHOWERS TO
LOCATIONS SOUTH OF THE CAPITAL REGION THURSDAY NIGHT INTO FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 650 AM EDT...COLD FRONT CONTINUES TO GRADUALLY MOVE SOUTH
ACROSS THE REGION THIS MORNING ALONG ROUGHLY A KCLE-KROC-KGFL-KPWM
AXIS. THE DEWPT BOUNDARY LAGS FURTHER NORTH AND WEST NEAR THE ST
LAWRENCE RIVER VALLEY. THE RADAR IS CURRENTLY QUIET...BUT WITH
PARTLY CLOUDY CONDITIONS FROM ALY SOUTH AND EAST...SOME ISOLD-SCT
SHOWERS/TSTMS WILL LIKELY DEVELOP NEAR THE MOHAWK RIVER VALLEY
BTWEEN 7 AM AND 10 AM. HOURLY T/TD/RH/APPARENT TEMPS RETRENDED
BASED ON OBSERVATIONS.
ONE MORE HUMID DAY IS EXPECTED ACROSS ERN NY AND
WRN NEW ENGLAND...AS RELIEF IS ON THE WAY. A MOIST AIR MASS IS IN
PLACE WITH SFC DEWPTS IN THE M60S TO L70S OVER THE FCST AREA. A
LULL IN THE CONVECTIVE ACTIVITY HAS OCCURRED OVER THE PAST FEW
HOURS...BUT CONVECTIVE INITIATION SHOULD INCREASE QUICKLY IN THE
LATE MORNING AND EARLY PM.
GENERAL THINKING HAS NOT CHANGED TOO MUCH WITH THE BEST DEEP SHEAR
AND INSTABILITY COMPOSITE OVERLAYS FROM THE NAM/GFS FOR LOCATIONS
JUST SOUTH AND EAST OF THE CAPITAL DISTRICT FOR POSSIBLE SVR WX TODAY.
CAUTION HAS TOO BE USED WITH THE GFS INSTABILITY CHARTS...AS SFC
DEWPTS ARE WELL INTO THE M70S OVER A LARGE CHUNK OF THE AREA SOUTH
OF ALBANY. A CORRECTION TO U60S TO L70S STILL YIELDS SBCAPE VALUES
IN THE 1000-2000 J/KG WITH SLIGHTLY HIGHER AMOUNTS. THE DEEP SHEAR
VALUES ARE ON THE NORTH SIDE OF THE BOUNDARY WITH 45-60
KTS. HOWEVER...0-6 KM BULK SHEAR VALUES ON THE NAM/GFS ARE STILL
30-40 KT FROM ALY SOUTH AND EAST. THERE MAY BE ENOUGH CONVERGENCE
AND LIFT WITH THE BOUNDARY FOR A FEW STRONG TO SEVERE STORMS. WE
ARE GOING TO DEVIATE SLIGHTLY FROM THE LATEST DAY 1 GRAPHIC...AND
FOCUS ON THE SEVERE THREAT FOR MAINLY THE ERN CATSKILLS...MID
HUDSON VALLEY...CNTRL AND SRN TACONICS...BERKSHIRES...AND NW CT.
THE COUNTIES WE WILL HIGHLIGHT IN THE HWO WILL BE
GREENE...ULSTER...COLUMBIA...DUTCHESS...BERKSHIRE...AND
LITCHFIELD.
PWAT VALUES WILL STILL BE IN THE 1.50-2.00 INCH RANGE FROM THE
CAPITAL REGION...MOHAWK VALLEY SOUTH AND EAST. SOME LOCALLY HEAVY
DOWNPOURS WILL BE POSSIBLE...AND SOME LOCATIONS COULD GET A QUICK
INCH OR TWO OF RAIN. FLASH FLOODING IS NOT EXPECTED. ALSO...THE
STRONG FLOW ALOFT SHOULD CONTINUE TO MOVE THE CONVECTION ALONG
DURING THE DAY.
CONVECTIVE INITIATION SHOULD OCCUR QUICKER TODAY WITH AN ERODING
CAP...AND THE CLOSER PROXIMITY OF THE FRONTAL BOUNDARY. THE
THUNDERSTORMS SHOULD POP UP AS SOON AS THE LATE MORNING IN THE
CNTRL-NRN PORTIONS OF CWA...AND SPREAD SOUTH OF ALY. WE KEPT THE
HIGHEST CHC TO LIKELY POPS FROM ALY SOUTH AND EAST DURING THE AFTERNOON.
HEAT INDICES/APPARENT TEMPS WILL GET INTO THE MID AND U90S OVER
PORTIONS OF THE MID HUDSON VALLEY...AND LITCHFIELD COUNTY...BUT
THEY SHOULD FALL SHY OF ADVISORY LEVELS WITH THE SHOWERS AND
THUNDERSTORMS MOVING IN. LATEST HIRES WRF HAS THE MOST ROBUST
CONVECTION WITH THE COMPOSITE REF PRODUCT GRAZING SRN DUTCHESS...AND
LITCHFIELD COUNTIES AFTER 21Z...THE LATEST HRRR IS A LITTLE BIT
FURTHER NORTH...BUT STILL SOUTH OF THE CAPITAL REGION...BUT HAS
THE STRONGER CONVECTION IMPACTING THE AREA BTWN 18Z-21Z. DAMAGING
WIND GUSTS WOULD BE THE MAIN THREAT WITH POTENTIAL BOWING SEGMENTS
WITH UNIDIRECTIONAL SHEAR PROFILES ON THE MODEL SOUNDINGS.
MAX TEMPS WILL RANGE FROM THE M80S TO L90S IN THE VALLEYS...WITH
SOME U70S OVER THE NRN MTNS TO LOWER TO MID80S OVER THE HILLS AND
MTNS SOUTH OF ALBANY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
TONIGHT...THE FRONT DIPS SOUTH OF THE FORECAST AREA WITH THE ISOLD-
SCT SHOWER AND THUNDERSTORM ACTIVITY ENDING BY AROUND MIDNIGHT FOR
THE SRN MOST ZONES. THE LOW LEVEL COLD ADVECTION WILL ALLOW H850
TEMPS TO LOWER TO 10 TO 14C FROM THE CAPITAL REGION NORTH AND
WEST...AND 14-17C TO THE SOUTH AND EAST. THE SKIES SHOULD CLEAR
OVERNIGHT...AND LOWS WILL BE IN THE U40S TO M50S NORTH OF
ALY...AND U50S TO L60S SOUTH AND EAST.
THURSDAY...A VERY NICE DAY IS SHAPING UP WITH STRONG SUBSIDENCE
IN WAKE OF THE FRONT...AND A LARGE SFC ANTICYCLONE BUILDING IN
FROM ONTARIO AND JAMES BAY. FEW-SCT FAIR WX CUMULUS WILL BE
AROUND...AND DECENT MIXING WILL ALLOW MAX TEMPS TO BE IN THE LOWER
TO M80S IN THE VALLEYS...AND MAINLY 70S OVER THE HILLS AND MTNS
/SOME U60S TOO/.
THURSDAY NIGHT...H500 UPPER LOW CONTINUES TO LIFT N/NE INTO THE
CANADIAN MARITIMES WITH BROAD SFC HIGH CONTINUING TO RIDGE IN FROM
JAMES BAY. FRONTAL BOUNDARY FROM WED...BECOMES STATIONARY OVER THE
MID ATLANTIC REGION. THE NAM/GFS/ECMWF/CAN GUIDANCE ALL SHOW A
DISTURBANCE MOVING ALONG THE BOUNDARY...WITH SOME THERMAL
ADVECTION SHOWERS GETTING INTO THE MID HUDSON VALLEY. WE PLACED
SOME SLIGHT CHC POPS FOR SHOWERS WELL SOUTH OF THE CAPITAL
REGION...OTHERWISE IT SHOULD BE A COOL AND COMFORTABLE EVENING
WITH LOWS IN THE 50S...EXCEPT FOR SOME 40S OVER THE SRN
DACKS...AND SRN GREENS...AND SOME L60S OVER THE MID HUDSON VALLEY.
FRI-FRI NIGHT...CLOUDS CONTINUE TO SPILL NORTH WITH THE WAVE
RIDING THE FRONTAL BOUNDARY OVER THE MID ATLANTIC REGION. THE SREF
POPS STILL REMAIN LOW IN THE SLIGHT CHC CATEGORY. WEAK THETA-E
ADVECTION AND ISENTROPIC LIFT COULD ALLOW A FEW-SCT SHOWERS SOUTH
OF THE CAPITAL REGION. MAX TEMPS WILL ACTUALLY BE WARMER FROM THE
CAPITAL REGION NORTH...WHERE MORE SUNSHINE MAY OCCUR. THE CLOUDS
AND ISOLD-SCT SHOWERS SHOULD CLEAR FRI NIGHT...AS THE SFC RIDGE
BUILDS BACK IN. TEMPS MAY ACTUALLY RUN A SHADE BELOW NORMAL THIS
DAY.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
THE LONG TERM PERIOD IS EXPECTED TO START DRY WITH THE POSSIBILITY
OF SOME UNSETTLED WEATHER LATE IN THE WEEKEND INTO EARLY NEXT WEEK.
TEMPS AND HUMIDITY WILL START TO INCREASE SLOWLY AS THE RIDGE OF
HIGH PRESSURE SLIDES OFF THE EASTERN SEABOARD AND A RETURN FLOW
STARTS TO DEVELOP. DRY WEATHER IS EXPECTED TO CONTINUE THROUGH
SUNDAY MORNING WITH WIDELY SCATTERED TO SCATTERED SHOWERS DEVELOPING
SUNDAY AFTERNOON AND CONTINUING INTO SUNDAY EVENING AS A COLD FRONT
DROPS SOUTHEAST TOWARD THE SAINT LAWRENCE VALLEY. EXPECT A BETTER
CHANCE OF SHOWERS AND THUNDERSTORMS MONDAY INTO MONDAY EVENING AS
THE COLD FRONT WORKS SOUTHEASTWARD THROUGH THE FA ENDING UP ACROSS
SOUTHEAST NY AND SOUTHERN NEW ENGLAND TUESDAY MORNING.
H8 TEMPS ARE EXPECTED TO RISE FROM +10 TO +11 C SATURDAY MORNING TO
+15 TO +17 C LATE SUNDAY AHEAD OF THE COLD FRONT AND THEN DROP TO
+10 TO +14 C BY LATE TUESDAY IN THE WAKE OF THE COLD FRONT.
EXPECT HIGHS ON SATURDAY TO BE IN THE MID 70S TO LOWER 80S...UPPER
70S TO MID 80S ON SUNDAY AND MONDAY...AND LOWER 70S TO MID 80S ON
TUESDAY. LOWS ARE GENERALLY EXPECTED TO BE IN THE MID 50S TO MID
60S...SATURDAY NIGHT THROUGH MONDAY NIGHT.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
VERY WARM AND HUMID CONDITIONS WILL CONTINUE UNTIL THE PASSAGE OF A
COLD FRONT LATE TODAY. THE BEST CHANCE OF SHOWERS AND THUNDERSTORMS
WILL BE ACROSS SOUTHERN AREAS AHEAD OF THE COLD FRONT THIS AFTERNOON
WITH CLEARING EXPECTED AT THE TAF SITES DURING THE EVENING.
WINDS WILL BECOME WEST TO NORTHWEST TODAY AND THEN EVENTUALLY
NORTHWEST TO NORTH AT 5 TO 10 KTS IN THE WAKE OF THE COLD FRONT. THE
EXCEPTION WILL BE AT KPOU WHERE SOUTHWEST WINDS AT 4-6 KTS ARE
EXPECTED THROUGH THIS AFTERNOON WILL BECOME NORTH AT AROUND 3 KTS
EARLY THIS EVENING. WINDS AT ALL THE TAF SITES WILL THEN BECOME
LIGHT AND VARIABLE BY MID TO LATE EVENING.
OUTLOOK...
THU-SAT..NO SIG WX.
SUN...VFR...SLIGHT CHC AFTERNOON TSTMS.
&&
.FIRE WEATHER...
A COLD FRONT WILL SLOWLY MOVE SOUTHWARD ACROSS EASTERN NEW YORK AND
WESTERN NEW ENGLAND TODAY WITH SOME SHOWERS AND THUNDERSTORMS. A
BROAD AREA OF HIGH PRESSURE WILL BUILD IN FROM JAMES BAY TONIGHT
INTO THURSDAY WITH SEASONABLE TEMPERATURES AND LESS HUMID
CONDITIONS.
RELATIVE HUMIDITY VALUES WILL LOWER TO 40-70 PERCENT TODAY...AND
RECOVER TO 90 TO 100 PERCENT TONIGHT. EXPECT MINIMUM RH VALUES OF
25 TO 50 PERCENT THURSDAY AFTERNOON.
THE WINDS WILL BE FROM THE WEST OR NORTHWEST AT 5 TO 15 MPH
TODAY...AND DECREASE TO LESS THAN 10 MPH TONIGHT. NORTH WINDS OF 5
TO 15 MPH WILL BE COMMON ON THURSDAY.
&&
.HYDROLOGY...
NO HYDRO PROBLEMS ARE EXPECTED ON THE MAIN STEM RIVERS OVER THE
NEXT 5 DAYS.
SHOWERS AND THUNDERSTORMS ASSOCIATED WITH A FRONTAL PASSAGE
TODAY WILL PRODUCE SOME HEAVY RAINFALL DUE TO A SHORT PERIOD OF
ANOMALOUSLY HIGH PRECIPITATELY WATER VALUES IN THE 1.5 TO 2 INCH
RANGE. SOME PONDING OF WATER ON ROADWAYS OR POOR DRAINAGE FLOODING
IS POSSIBLE ESPECIALLY FROM THE CAPITAL REGION SOUTH. ZONAL FLASH FLOOD
GUIDANCE VALUES REMAIN HIGH FOR MID JULY. THE POTENTIAL FOR FLASH
FLOODING IS LOW AT THIS TIME IN THE ALY HYDRO SERVICE AREA.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING
OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE
VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON
OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...WASULA
NEAR TERM...WASULA
SHORT TERM...WASULA
LONG TERM...11
AVIATION...11
FIRE WEATHER...WASULA
HYDROLOGY...WASULA
AREA FORECAST DISCUSSION
NWS NEW YORK NY
650 AM EDT WED JUL 18 2012
.SYNOPSIS...
A SLOW MOVING COLD FRONT FROM THE NORTH WILL MOVE INTO THE REGION
THIS AFTERNOON AND SOUTH OF THE REGION LATE TONIGHT INTO THURSDAY.
THE FRONT WILL THEN STALL WITH A WEAK AREA OF LOW PRESSURE MOVING
ALONG IT. LOW PRESSURE PASSES TO THE SOUTH ON FRIDAY WITH HIGH
PRESSURE BUILDING IN FROM THE NORTH THROUGH THE WEEKEND. ANOTHER
COLD FRONT WILL TRACK ACROSS THE AREA ON TUESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
FORECAST GENERALLY ON TRACK WITH JUST SLIGHT DOWNWARD ADJUSTMENTS
WITH SOME TEMPS EARLY THIS MORNING AND CLOUD COVERAGE. DRY WEATHER
EXPECTED WITH RELATIVELY WARM CONDITIONS THIS MORNING.
A SLOW MOVING COLD FRONT FROM THE NORTH WILL MOVE INTO THE REGION
THIS AFTERNOON. WITH THE REGION BEING ON THE NE EDGE OF A VERY HOT
AIRMASS...DAY STARTS OUT VERY WARM AND LARGE CAPE IN THE 2000 TO
4000 J/KG RANGE IS EXPECTED TO BUILD WITH DIURNAL WARMING. SHEAR
OF 30 KT 0-6KM WITH WETBULB ZERO HEIGHTS OF 13-14 KFT. MENTIONED
GUSTY WINDS AND SMALL HAIL WITH SOME CELLS HAVING A SLIGHT CHANCE
OF GOING SEVERE.
BEFORE COVERAGE OF SHOWERS AND THUNDERSTORMS BECOMES
WIDESPREAD...AT LEAST SOUTHERN PORTIONS OF THE REGION WILL SEE
ENOUGH SUN TO HAVE HIGHS WELL INTO THE 90S AND WITH VERY MOIST
AIRMASS CONVEYED BY PWATS NEAR 2 INCHES AND DEWPOINTS IN THE LOWER
70S...HEAT INDICES ARE EXPECTED TO BE NEAR 100 DEGREES FOR NEW
YORK CITY AS WELL AS URBAN SECTIONS OF SOUTHERN WESTCHESTER...MOST
OF NE NJ AND WESTERN LONG ISLAND.
FARTHER UP NORTH IN LOWER HUDSON VALLEY AND SOUTHERN CT WILL DEPEND
ON HOW FAST CONVECTION DEVELOPS AND THE INHERENT MITIGATION OF
DIURNAL WARMTH ASSOCIATED WITH EXPANDING CIRRUS CLOUD SHIELD OF
CONVECTION. RIGHT NOW...KEPT THEM LOWER WITHOUT HEAT ADVISORY BUT
HEAT INDICES ARE EXPECTED TO REACH MID TO UPPER 90S BEFORE
CONVECTION INCREASES SUBSTANTIALLY IN COVERAGE THIS AFTERNOON.
WILL START OFF THE HEAT ADVISORY LATE THIS MORNING BY 10 AM SINCE WE
WILL BE COMMENCING THE DIURNAL PERIOD AT A MUCH WARMER TEMPERATURE
THIS MORNING. MOST MODELS START TO BRING IN THE SHOWERS AND
THUNDERSTORMS BY 18Z ACROSS THE NORTHERN TIER AND BY 00Z ACROSS THE
ENTIRE AREA. ONLY EXCEPTION IS ECMWF WHICH HAS CONSISTENTLY HELD
BACK CONVECTION FOR LONG ISLAND UNTIL AFTER 00Z THU.
BASED ON MESOSCALE MODELS OF HRRR AND NSSL WRF...STRENGTHENING
CONVECTIVE CELLS START FIRING UP ALONG ACROSS THE ALLEGHENY PLATEAU
AND THE HUDSON VALLEY AROUND 17Z AFTER WHICH THEY WILL BE ON A
SOUTHEAST TRACK GOING INTO THE LOCAL FORECAST REGION. FURTHER
DEVELOPMENT OF CONVECTION COULD ALSO OCCUR FROM CONVERGENCE ALONG
THE SEA BREEZE BOUNDARY ESPECIALLY WITH ANY OUTFLOW BOUNDARIES FROM
CONVECTION MOVING IN FROM THE NORTH AND WEST. WIND SHEAR OF 25 TO 30
KT FROM 0-6 KM WILL ALLOW FOR SOME THUNDERSTORMS TO PRODUCE HAIL AND
GUSTY WINDS. PWATS NEAR 2 INCHES SO HEAVY RAIN ALSO CAN BE EXPECTED
WITH THUNDERSTORMS THAT FORM. THIS IS CONSIDERED ESPECIALLY SINCE
THE FLOW WILL BE NEARLY PARALLEL FROM LOW TO MID LEVELS WHICH WOULD
ALLOW FOR TRAINING OF CELLS. THE CONVECTIVE MODE LOOKS TO BE SQUALL
LINE TO BOW ECHOES.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/...
TONIGHT...RELATIVELY BETTER SHEAR ARRIVES WITH WINDS ALOFT AT 250MB
INCREASING AN EXTRA 10KT...PROMOTING GREATER DIVERGENCE. SOME
GREATER HEIGHT FALLS AT 500MB WILL ALSO IMPLY SOME GREATER SYNOPTIC
FORCING. THEREFORE EVEN THOUGH CAPE WILL BE ON A LOWERING
TREND...SOME THUNDERSTORMS WILL STILL MAINTAIN STRONG INTENSITIES
WITH HEAVY RAIN ALSO STILL POSSIBLE AS PWATS REMAIN NEAR 2 INCHES.
THE FRONT MOVES THROUGH LATE IN THE EVENING AND THEN SOUTH OF LONG
ISLAND GOING INTO THURSDAY. THE FRONT STALLS WITH A WEAK AREA OF LOW
PRESSURE MOVING IT. SOUTHERN PORTIONS OF THE FORECAST AREA COULD SEE
SOME LINGERING SHOWERS FROM TIME TO TIME ON THURSDAY AS A RESULT.
POPS ARE AT SLIGHT CHANCE WITH MODEL UNCERTAINTY DUE TO DIFFERENCES
IN QPF FIELDS AND RUN TO RUN INCONSISTENCY. IN THE UPPER LEVELS AT
500MB...THE AREA WILL BE IN A NW FLOW WITH A LONGWAVE TROUGH SETTING
UP ACROSS THE NORTHEAST. WENT WITH MORE OF THE COOLER GUIDANCE FOR
HIGHS CONSIDERING THE MORE EASTERLY FLOW. NOT EXPECTING ANY
THUNDERSTORMS WITH THIS ACTIVITY WITH MORE STABLE SFC CONDITIONS
FORECAST.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
A MEAN TROUGH WILL REMAIN OVER THE NE CONUS THROUGH THE PERIOD WHILE
A PERSISTENT AND STRONG RIDGE ALOFT REMAINS ENTRENCHED OVER THE
PLAINS AND ROCKIES.
COLD FRONT SLOWLY PRESSES SOUTHWARD THROUGH THE MID ATLANTIC STATES
THROUGH FRIDAY WITH CANADIAN HIGH PRES BUILDING IN FROM THE N. AN
AREA OF LOW PRES IS FORECAST TO DEVELOP ON THE FRONT THU NIGHT AND
PASS TO THE S FRI MORNING WITH AN UPPER LEVEL TROUGH SWINGING
THROUGH ALOFT. AN EASTERLY FLOW WILL MOISTEN LOW LEVELS WITH THE CHC
OF SHOWERS ON FRI. MODELS HAVE BEEN CONSISTENT WITH THIS FOR THE
LAST DAY...SO HAVE ADDED CHC POPS TO THE FORECAST. ABUNDANT CLOUD
COVER AND ONSHORE FLOW WILL RESULT IN A MUCH COOLER DAY ACROSS THE
AREA WITH HIGHS ONLY EXPECTED TO REACH THE UPPER 70S AT MOST
LOCATIONS. AS THE FRONT SINKS FURTHER S LATER FRI AND FRI NIGHT
DRIER AND MORE STABLE AIR WILL WORK IN FROM THE N AND E WITH DRY
WEATHER AND SEASONABLE THROUGH THE WEEKEND.
WAA ENSUES EARLY NEXT WEEK WITH H85 TEMPS RISING INTO THE UPPER
TEENS ON MON RESULTING IN TEMPS RISING A FEW DEGREES ABOVE NORMAL
LEVELS MON. PRE-FRONTAL TROUGH MAY TRIGGER ISOLD-SCT STORMS MON AFTN
AS COLD FRONT APPROACHES FROM THE NW. TYPICAL GFS IS FASTER THAN THE
EC WITH THE FROPA SO HAVE COMPROMISED THE TIMING WITH IT COMING
THROUGH TUE MORNING. DRY AND SEASONABLE WEATHER COURTESY OF HIGH
PRES THEN BUILDS BACK IN OVER THE AREA.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
A TROUGH OF LOW PRESSURE WILL REMAIN IN THE VICINITY THIS
MORNING...THEN A COLD FRONT MOVES INTO THE TERMINALS DURING THE
AFTERNOON...MOVING SOUTH THIS EVENING.
MAINLY VFR OUTSIDE OF TSTMS...ALTHOUGH HZ MAY RESTRICT VSBY TO
AROUND 6SM ACROSS COASTAL TERMINALS. OCCASIONAL GUSTY SW WINDS AT
NYC/NJ TERMINALS FROM MID MORNING ON.
ISOLATED TSTMS POSSIBLE BY LATE MORNING...BECOMING LIKELY IN THE
EARLY AFTERNOON AND CONTINUING INTO THE EARLY EVENING. THREAT OF
GUSTY WINDS...HAIL AND HEAVY RAINFALL EXISTS WITH STRONGER
CONVECTION. CONVECTION EXPECTED TO TAPER AND WEAKEN DURING THROUGH
THE EVENING HOURS.
HYBRID SEABREEZE AND SW FLOW ACROSS COASTAL TERMINALS THIS
AFTERNOON.
NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS
CAN BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KJFK FCSTER COMMENTS: MODERATE CONFIDENCE ON CONVECTION OCCURRING
AT SOME POINT DURING THE AFTERNOON...BUT LOW CONFIDENCE IN EXACT
TIMING IN THE TAFS. HYBRID SEABREEZE/SW FLOW THIS AFTERNOON.
KLGA FCSTER COMMENTS: MODERATE CONFIDENCE ON CONVECTION OCCURRING
AT SOME POINT DURING THE AFTERNOON...BUT LOW CONFIDENCE IN EXACT
TIMING IN THE TAFS.
KEWR FCSTER COMMENTS: MODERATE CONFIDENCE ON CONVECTION OCCURRING
AT SOME POINT DURING THE AFTERNOON...BUT LOW CONFIDENCE IN EXACT
TIMING IN THE TAFS.
THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH
IMPLIES SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD.
KTEB FCSTER COMMENTS: MODERATE CONFIDENCE ON CONVECTION OCCURRING
AT SOME POINT DURING THE AFTERNOON...BUT LOW CONFIDENCE IN EXACT
TIMING IN THE TAFS. OCCASIONAL GUSTS POSSIBLE FROM LATE MORNING
THROUGH THE AFTERNOON.
KHPN FCSTER COMMENTS: MODERATE CONFIDENCE ON CONVECTION OCCURRING
AT SOME POINT DURING THE AFTERNOON...BUT LOW CONFIDENCE IN EXACT
TIMING IN THE TAFS. OCCASIONAL GUSTS POSSIBLE FROM LATE MORNING
THROUGH THE AFTERNOON.
KISP FCSTER COMMENTS: MODERATE CONFIDENCE ON CONVECTION OCCURRING
AT SOME POINT DURING THE AFTERNOON...BUT LOW CONFIDENCE IN EXACT
TIMING IN THE TAFS. HYBRID SEABREEZE/SW FLOW THIS AFTERNOON.
OUTLOOK FOR 06Z THURSDAY THROUGH SUNDAY...
.LATE TONIGHT...MAINLY VFR...EXCEPT PATCHY GROUND FOG ACROSS
OUTLYING TERMINALS.
.THURSDAY-THURSDAY EVENING...VFR. SCATTERED SHOWERS POSSIBLE.
.LATE THURSDAY NIGHT-SATURDAY MORNING...CEILINGS 1500 FT TO 2500 FT
POSSIBLE...BEST CHANCE AT SOUTHERN/COASTAL TERMINALS.
.SATURDAY AFTERNOON-SUNDAY...VFR.
&&
.MARINE...
MARGINAL SCA CONDITIONS ARE POSSIBLE AT TIMES ACROSS OUTER OCEAN
WATERS IN THE SHORT TERM THROUGH THURSDAY NIGHT. HOWEVER...KEPT
OCEAN SEAS BELOW 5 FT SINCE WAVEWATCH INITIALLY ABOUT A FOOT TOO
HIGH COMPARED TO OBS.
MARGINAL SCA CONDS ARE POSSIBLE ON THE OCEAN WATERS FRI/FRI NIGHT
WITH AN INCREASING EASTERLY FLOW BETWEEN HIGH PRES BUILDING IN FROM
THE N AND LOW PRES PASSING TO THE S. A RELATIVELY LIGHT SE-S FLOW
WILL THEN PREVAIL WITH SUB-ADVSY CONDS THEREAFTER. HAVE CUT A FT OFF
OF WAVEWATCH GUIDANCE THROUGH THE PERIOD AS IT CONTINUES TO RUN
HIGH.
&&
.HYDROLOGY...
NO PRECIPITATION IS EXPECTED INTO THIS MORNING.
FLASH FLOODING IS POSSIBLE WITH ANY TRAINING CONVECTION THIS
AFTERNOON AND EVENING AS PWATS INCREASE TO AROUND 2 INCHES AND
STEERING FLOW NEARLY ALIGNS WITH FRONTAL BOUNDARY. A BASIN AVERAGE
QPF OF AROUND 1/4 TO 1/2 INCH IS POSSIBLE ACROSS THE AREA...WITH
LOCALIZED AMOUNTS IN EXCESS OF 2 INCHES POSSIBLE WITH ANY TRAINING
CONVECTION.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...HEAT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR NYZ072>075-176-
178.
HEAT ADVISORY FROM 10 AM THIS MORNING TO 6 PM EDT THIS EVENING
FOR NYZ071-078-080-177-179.
NJ...HEAT ADVISORY FROM 10 AM THIS MORNING TO 6 PM EDT THIS EVENING
FOR NJZ004-006-103>108.
MARINE...NONE.
&&
$$
SYNOPSIS...JM
NEAR TERM...JM
SHORT TERM...JM
LONG TERM...24
AVIATION...NV
MARINE...24/JM
HYDROLOGY...24/JM
AREA FORECAST DISCUSSION
NWS NEW YORK NY
508 AM EDT WED JUL 18 2012
.SYNOPSIS...
A SLOW MOVING COLD FRONT FROM THE NORTH WILL MOVE INTO THE REGION
THIS AFTERNOON AND SOUTH OF THE REGION LATE TONIGHT INTO THURSDAY.
THE FRONT WILL THEN STALL WITH A WEAK AREA OF LOW PRESSURE MOVING
ALONG IT. LOW PRESSURE PASSES TO THE SOUTH ON FRIDAY WITH HIGH
PRESSURE BUILDING IN FROM THE NORTH THROUGH THE WEEKEND. ANOTHER
COLD FRONT WILL TRACK ACROSS THE AREA ON TUESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
OUTSIDE OF A FEW ISOLATED SHOWERS THIS MORNING FROM INTERACTION
BETWEEN LOW LEVEL JET AND APPROACHING MID LEVEL DISTURBANCE...DRY
WEATHER EXPECTED WITH RELATIVELY WARM CONDITIONS THIS MORNING.
A SLOW MOVING COLD FRONT FROM THE NORTH WILL MOVE INTO THE REGION
THIS AFTERNOON. WITH THE REGION BEING ON THE NE EDGE OF A VERY HOT
AIRMASS...DAY START OUT VERY WARM AND LARGE CAPE IN THE 2000 TO
4000 J/KG RANGE IS EXPECTED TO BUILD WITH DIURNAL WARMING. SHEAR
OF 30 KT 0-6KM WITH WETBULB ZERO HEIGHTS OF 13-14 KFT. MENTIONED
GUSTY WINDS AND SMALL HAIL WITH SOME CELLS POSSIBLY GOING SEVERE.
BEFORE COVERAGE OF SHOWERS AND THUNDERSTORMS BECOMES
WIDESPREAD...AT LEAST SOUTHERN PORTIONS OF THE REGION WILL SEE
ENOUGH SUN TO HAVE HIGHS WELL INTO THE 90S AND WITH VERY MOIST
AIRMASS CONVEYED BY PWATS NEAR 2 INCHES AND DEWPOINTS IN THE LOWER
70S...HEAT INDICES ARE EXPECTED TO BE NEAR 100 DEGREES FOR NEW
YORK CITY AS WELL AS URBAN SECTIONS OF SOUTHERN WESTCHESTER...MOST
OF NE NJ AND WESTERN LONG ISLAND.
FARTHER UP NORTH IN LOWER HUDSON VALLEY AND SOUTHERN CT WILL DEPEND
ON HOW FAST CONVECTION DEVELOPS AND THE INHERENT MITIGATION OF
DIURNAL WARMTH ASSOCIATED WITH EXPANDING CIRRUS CLOUD SHIELD OF
CONVECTION. RIGHT NOW...KEPT THEM LOWER WITHOUT HEAT ADVISORY BUT
HEAT INDICES ARE EXPECTED TO REACH MID TO UPPER 90S BEFORE
CONVECTION INCREASES SUBSTANTIALLY IN COVERAGE THIS AFTERNOON.
WILL START OFF THE HEAT ADVISORY LATE THIS MORNING BY 10 AM SINCE WE
WILL BE COMMENCING THE DIURNAL PERIOD AT A MUCH WARMER TEMPERATURE
THIS MORNING. MOST MODELS START TO BRING IN THE SHOWERS AND
THUNDERSTORMS BY 18Z ACROSS THE NORTHERN TIER AND BY 00Z ACROSS THE
ENTIRE AREA. ONLY EXCEPTION IF ECMWF WHICH HAS CONSISTENTLY HELD
BACK CONVECTION FOR LONG ISLAND UNTIL AFTER 00Z THU.
BASED ON MESOSCALE MODELS OF HRRR AND NSSL WRF...STRENGTHENING
CONVECTIVE CELLS START FIRING UP ALONG ACROSS THE ALLEGHENY PLATEAU
AND THE HUDSON VALLEY AROUND 17Z AFTER WHICH THEY WILL BE ON A
SOUTHEAST TRACK GOING INTO THE LOCAL FORECAST REGION. SHEAR OF 25
TO 30 KT FROM 0-6 KM WILL ALLOW FOR SOME THUNDERSTORMS TO PRODUCE
HAIL AND GUSTY WINDS. PWATS NEAR 2 INCHES SO HEAVY RAIN ALSO
POSSIBLE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/...
FOR TONIGHT...BETTER SHEAR ARRIVES WITH WINDS ALOFT AT 250MB
INCREASING AN EXTRA 10KT...PROMOTING GREATER DIVERGENCE. SOME
GREATER HEIGHT FALLS AT 500MB WILL ALSO IMPLY SOME GREATER SYNOPTIC
FORCING. THEREFORE EVEN THOUGH CAPE WILL BE ON A LOWERING
TREND...SOME THUNDERSTORMS WILL STILL MAINTAIN STRONG INTENSITIES
WITH HEAVY RAIN ALSO STILL POSSIBLE.
THE FRONT MOVES THROUGH LATE IN THE EVENING AND THEN SOUTH OF LONG
ISLAND GOING INTO THURSDAY. THE FRONT STALLS WITH A WEAK AREA OF LOW
PRESSURE MOVING IT. SOUTHERN PORTIONS OF THE FORECAST AREA COULD SEE
SOME SHOWERS FROM TIME TO TIME ON THURSDAY AS A RESULT. IN THE UPPER
LEVELS AT 500MB...THE AREA WILL BE IN A NW FLOW WITH A LONGWAVE
TROUGH SETTING UP ACROSS THE NORTHEAST. WENT WITH MORE OF THE COOLER
GUIDANCE FOR HIGHS CONSIDERING THE MORE EASTERLY FLOW. NOT EXPECTING
ANY THUNDERSTORMS WITH THIS ACTIVITY WITH MORE STABLE SFC CONDITIONS
FORECAST.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
A MEAN TROUGH WILL REMAIN OVER THE NE CONUS THROUGH THE PERIOD WHILE
A PERSISTENT AND STRONG RIDGE ALOFT REMAINS ENTRENCHED OVER THE
PLAINS AND ROCKIES.
COLD FRONT SLOWLY PRESSES SOUTHWARD THROUGH THE MID ATLANTIC STATES
THROUGH FRIDAY WITH CANADIAN HIGH PRES BUILDING IN FROM THE N. AN
AREA OF LOW PRES IS FORECAST TO DEVELOP ON THE FRONT THU NIGHT AND
PASS TO THE S FRI MORNING WITH AN UPPER LEVEL TROUGH SWINGING
THROUGH ALOFT. AN EASTERLY FLOW WILL MOISTEN LOW LEVELS WITH THE CHC
OF SHOWERS ON FRI. MODELS HAVE BEEN CONSISTENT WITH THIS FOR THE
LAST DAY...SO HAVE ADDED CHC POPS TO THE FORECAST. ABUNDANT CLOUD
COVER AND ONSHORE FLOW WILL RESULT IN A MUCH COOLER DAY ACROSS THE
AREA WITH HIGHS ONLY EXPECTED TO REACH THE UPPER 70S AT MOST
LOCATIONS. AS THE FRONT SINKS FURTHER S LATER FRI AND FRI NIGHT
DRIER AND MORE STABLE AIR WILL WORK IN FROM THE N AND E WITH DRY
WEATHER AND SEASONABLE THROUGH THE WEEKEND.
WAA ENSUES EARLY NEXT WEEK WITH H85 TEMPS RISING INTO THE UPPER
TEENS ON MON RESULTING IN TEMPS RISING A FEW DEGREES ABOVE NORMAL
LEVELS MON. PRE-FRONTAL TROUGH MAY TRIGGER ISOLD-SCT STORMS MON AFTN
AS COLD FRONT APPROACHES FROM THE NW. TYPICAL GFS IS FASTER THAN THE
EC WITH THE FROPA SO HAVE COMPROMISED THE TIMING WITH IT COMING
THROUGH TUE MORNING. DRY AND SEASONABLE WEATHER COURTESY OF HIGH
PRES THEN BUILDS BACK IN OVER THE AREA.
&&
.AVIATION /09Z WEDNESDAY THROUGH SUNDAY/...
A TROUGH OF LOW PRESSURE WILL REMAIN IN THE VICINITY THIS
MORNING...THEN A COLD FRONT MOVES INTO THE TERMINALS DURING THE
AFTERNOON...MOVING SOUTH THIS EVENING.
MAINLY VFR OUTSIDE OF TSTMS...ALTHOUGH HZ MAY RESTRICT VSBY TO
AROUND 6SM ACROSS COASTAL TERMINALS. OCCASIONAL GUSTY SW WINDS AT
NYC/NJ TERMINALS FROM MID MORNING ON.
ISOLATED TSTMS POSSIBLE BY LATE MORNING...BECOMING LIKELY IN THE
EARLY AFTERNOON AND CONTINUING INTO THE EARLY EVENING. THREAT OF
GUSTY WINDS...HAIL AND HEAVY RAINFALL EXISTS WITH STONGER
CONVECTION. CONVECTION EXPECTED TO TAPER AND WEAKEN DURING THROUGH
THE EVENING HOURS.
HYBRID SEABREEZE AND SW FLOW ACROSS COASTAL TERMINALS THIS
AFTERNOON.
...NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS
CAN BE FOUND AT: HTTP://WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KJFK FCSTER COMMENTS: MODERATE CONFIDENCE ON CONVECTION OCCURRING
AT SOME POINT DURING THE AFTERNOON...BUT LOW CONFIDENCE IN EXACT
TIMING IN THE TAFS. HYBRID SEABREEZE/SW FLOW THIS AFTERNOON.
KLGA FCSTER COMMENTS: MODERATE CONFIDENCE ON CONVECTION OCCURRING
AT SOME POINT DURING THE AFTERNOON...BUT LOW CONFIDENCE IN EXACT
TIMING IN THE TAFS.
KEWR FCSTER COMMENTS: MODERATE CONFIDENCE ON CONVECTION OCCURRING
AT SOME POINT DURING THE AFTERNOON...BUT LOW CONFIDENCE IN EXACT
TIMING IN THE TAFS.
THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH
IMPLIES SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD.
KTEB FCSTER COMMENTS: MODERATE CONFIDENCE ON CONVECTION OCCURRING
AT SOME POINT DURING THE AFTERNOON...BUT LOW CONFIDENCE IN EXACT
TIMING IN THE TAFS. OCCASIONAL GUSTS POSSIBLE FROM LATE MORNING
THROUGH THE AFTERNOON.
KHPN FCSTER COMMENTS: MODERATE CONFIDENCE ON CONVECTION OCCURRING
AT SOME POINT DURING THE AFTERNOON...BUT LOW CONFIDENCE IN EXACT
TIMING IN THE TAFS. OCCASIONAL GUSTS POSSIBLE FROM LATE MORNING
THROUGH THE AFTERNOON.
KISP FCSTER COMMENTS: MODERATE CONFIDENCE ON CONVECTION OCCURRING
AT SOME POINT DURING THE AFTERNOON...BUT LOW CONFIDENCE IN EXACT
TIMING IN THE TAFS. HYBRID SEABREEZE/SW FLOW THIS AFTERNOON.
OUTLOOK FOR 06Z THURSDAY THROUGH SUNDAY...
.LATE TONIGHT...MAINLY VFR...EXCEPT PATCHY GROUND FOG ACROSS
OUTLYING TERMINALS.
.THURSDAY-THURSDAY EVENING...VFR. SCATTERED SHOWERS POSSIBLE.
.LATE THURSDAY NIGHT-SATURDAY MORNING...CEILINGS 1500 FT TO 2500 FT
POSSIBLE...BEST CHANCE AT SOUTHERN/COASTAL TERMINALS.
.SATURDAY AFTERNOON-SUNDAY...VFR.
&&
.MARINE...
MARGINAL SCA CONDITIONS ARE POSSIBLE ACROSS OCEAN WATERS LATER
TODAY AND TONIGHT. HOWEVER...KEPT SEAS BELOW 5 FT SINCE WAVEWATCH
INITIALLY ABOUT A FOOT TOO HIGH. SUB SCA EXPECTED ON THURSDAY AND
THURSDAY NIGHT.
MARGINAL SCA CONDS ARE POSSIBLE ON THE OCEAN WATERS FRI/FRI NIGHT
WITH AN INCREASING EASTERLY FLOW BETWEEN HIGH PRES BUILDING IN FROM
THE N AND LOW PRES PASSING TO THE S. A RELATIVELY LIGHT SE-S FLOW
WILL THEN PREVAIL WITH SUB-ADVSY CONDS THEREAFTER. HAVE CUT A FT OFF
OF WAVEWATCH GUIDANCE THROUGH THE PERIOD AS IT CONTINUES TO RUN
HIGH.
&&
.HYDROLOGY...
NO PRECIPITATION IS EXPECTED INTO THIS MORNING.
FLASH FLOODING IS POSSIBLE WITH ANY TRAINING CONVECTION THIS
AFTERNOON AND EVENING AS PWATS INCREASE TO AROUND 2 INCHES AND
STEERING FLOW NEARLY ALIGNS WITH FRONTAL BOUNDARY. A BASIN AVERAGE
QPF OF AROUND 1/2 INCH IS POSSIBLE ACROSS THE AREA...WITH
LOCALIZED AMOUNTS IN EXCESS OF 2 INCHES POSSIBLE WITH ANY TRAINING
CONVECTION.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...HEAT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR NYZ072>075-176-
178.
HEAT ADVISORY FROM 10 AM THIS MORNING TO 6 PM EDT THIS EVENING
FOR NYZ071-078-080-177-179.
NJ... HEAT ADVISORY FROM 10 AM THIS MORNING TO 6 PM EDT THIS EVENING
FOR NJZ004-006-103>108.
MARINE...NONE.
&&
$$
SYNOPSIS...JM
NEAR TERM...JM
SHORT TERM...JM
LONG TERM...24
AVIATION...NV
MARINE...24/JM
HYDROLOGY...24/JM
AREA FORECAST DISCUSSION...CORRECTED
NWS NEW YORK NY
440 AM EDT WED JUL 18 2012
.SYNOPSIS...
A SLOW MOVING COLD FRONT FROM THE NORTH WILL MOVE INTO THE REGION
THIS AFTERNOON AND SOUTH OF THE REGION LATE TONIGHT INTO THURSDAY.
THE FRONT WILL THEN STALL WITH A WEAK AREA OF LOW PRESSURE MOVING
ALONG IT. LOW PRESSURE PASSES TO THE SOUTH ON FRIDAY WITH HIGH
PRESSURE BUILDING IN FROM THE NORTH THROUGH THE WEEKEND. ANOTHER
COLD FRONT WILL TRACK ACROSS THE AREA ON TUESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
OUTSIDE OF A FEW ISOLATED SHOWERS THIS MORNING FROM INTERACTION
BETWEEN LOW LEVEL JET AND APPROACHING MID LEVEL DISTURBANCE...DRY
WEATHER EXPECTED WITH RELATIVELY WARM CONDITIONS THIS MORNING.
A SLOW MOVING COLD FRONT FROM THE NORTH WILL MOVE INTO THE REGION
THIS AFTERNOON. WITH THE REGION BEING ON THE NE EDGE OF A VERY HOT
AIRMASS...DAY START OUT VERY WARM AND LARGE CAPE IN THE 2000 TO
4000 J/KG RANGE IS EXPECTED TO BUILD WITH DIURNAL WARMING. SHEAR
OF 30 KT 0-6KM WITH WETBULB ZERO HEIGHTS OF 13-14 KFT. MENTIONED
GUSTY WINDS AND SMALL HAIL WITH SOME CELLS POSSIBLY GOING SEVERE.
BEFORE COVERAGE OF SHOWERS AND THUNDERSTORMS BECOMES WIDESPREAD...AT
LEAST SOUTHERN PORTIONS OF THE REGION WILL SEE ENOUGH SUN TO HAVE
HIGHS WELL INTO THE 90S AND WITH VERY MOIST AIRMASS CONVEYED BY
PWATS NEAR 2 INCHES AND DEWPOINTS IN THE LOWER 70S...HEAT INDICES
ARE EXPECTED TO BE NEAR 100 DEGREES FOR NEW YORK CITY AS WELL AS
URBAN SECTIONS OF SOUTHERN WESTCHESTER...MOST OF NE NJ AND WESTERN
LONG ISLAND.
FARTHER UP NORTH IN LOWER HUDSON VALLEY AND SOUTHERN CT WILL DEPEND
ON HOW FAST CONVECTION DEVELOPS AND THE INHERENT MITIGATION OF
DIURNAL WARMTH ASSOCIATED WITH EXPANDING CIRRUS CLOUD SHIELD OF
CONVECTION. RIGHT NOW...KEPT THEM LOWER WITHOUT HEAT ADVISORY BUT
HEAT INDICES ARE EXPECTED TO REACH MID TO UPPER 90S BEFORE
CONVECTION INCREASES SUBSTANTIALLY IN COVERAGE THIS AFTERNOON.
WILL START OFF THE HEAT ADVISORY LATE THIS MORNING BY 10 AM SINCE WE
WILL BE COMMENCING THE DIURNAL PERIOD AT A MUCH WARMER TEMPERATURE
THIS MORNING. MOST MODELS START TO BRING IN THE SHOWERS AND
THUNDERSTORMS BY 18Z ACROSS THE NORTHERN TIER AND BY 00Z ACROSS THE
ENTIRE AREA. ONLY EXCEPTION IF ECMWF WHICH HAS CONSISTENTLY HELD
BACK CONVECTION FOR LONG ISLAND UNTIL AFTER 00Z THU.
BASED ON MESOSCALE MODELS OF HRRR AND NSSL WRF...STRENGTHENING
CONVECTIVE CELLS START FIRING UP ALONG ACROSS THE ALLEGHENY PLATEAU
AND THE HUDSON VALLEY AROUND 17Z AFTER WHICH THEY WILL BE ON A
SOUTHEAST TRACK GOING INTO THE LOCAL FORECAST REGION. SHEAR OF 25
TO 30 KT FROM 0-6 KM WILL ALLOW FOR SOME THUNDERSTORMS TO PRODUCE
HAIL AND GUSTY WINDS. PWATS NEAR 2 INCHES SO HEAVY RAIN ALSO
POSSIBLE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/...
FOR TONIGHT...BETTER SHEAR ARRIVES WITH WINDS ALOFT AT 250MB
INCREASING AN EXTRA 10KT...PROMOTING GREATER DIVERGENCE. SOME
GREATER HEIGHT FALLS AT 500MB WILL ALSO IMPLY SOME GREATER SYNOPTIC
FORCING. THEREFORE EVEN THOUGH CAPE WILL BE ON A LOWERING
TREND...SOME THUNDERSTORMS WILL STILL MAINTAIN STRONG INTENSITIES
WITH HEAVY RAIN ALSO STILL POSSIBLE.
THE FRONT MOVES THROUGH LATE IN THE EVENING AND THEN SOUTH OF LONG
ISLAND GOING INTO THURSDAY. THE FRONT STALLS WITH A WEAK AREA OF LOW
PRESSURE MOVING IT. SOUTHERN PORTIONS OF THE FORECAST AREA COULD SEE
SOME SHOWERS FROM TIME TO TIME ON THURSDAY AS A RESULT. IN THE UPPER
LEVELS AT 500MB...THE AREA WILL BE IN A NW FLOW WITH A LONGWAVE
TROUGH SETTING UP ACROSS THE NORTHEAST. WENT WITH MORE OF THE COOLER
GUIDANCE FOR HIGHS CONSIDERING THE MORE EASTERLY FLOW. NOT EXPECTING
ANY THUNDERSTORMS WITH THIS ACTIVITY WITH MORE STABLE SFC CONDITIONS
FORECAST.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
A MEAN TROUGH WILL REMAIN OVER THE NE CONUS THROUGH THE PERIOD WHILE
A PERSISTENT AND STRONG RIDGE ALOFT REMAINS ENTRENCHED OVER THE
PLAINS AND ROCKIES.
COLD FRONT SLOWLY PRESSES SOUTHWARD THROUGH THE MID ATLANTIC STATES
THROUGH FRIDAY WITH CANADIAN HIGH PRES BUILDING IN FROM THE N. AN
AREA OF LOW PRES IS FORECAST TO DEVELOP ON THE FRONT THU NIGHT AND
PASS TO THE S FRI MORNING WITH AN UPPER LEVEL TROUGH SWINGING
THROUGH ALOFT. AN EASTERLY FLOW WILL MOISTEN LOW LEVELS WITH THE CHC
OF SHOWERS ON FRI. MODELS HAVE BEEN CONSISTENT WITH THIS FOR THE
LAST DAY...SO HAVE ADDED CHC POPS TO THE FORECAST. ABUNDANT CLOUD
COVER AND ONSHORE FLOW WILL RESULT IN A MUCH COOLER DAY ACROSS THE
AREA WITH HIGHS ONLY EXPECTED TO REACH THE UPPER 70S AT MOST
LOCATIONS. AS THE FRONT SINKS FURTHER S LATER FRI AND FRI NIGHT
DRIER AND MORE STABLE AIR WILL WORK IN FROM THE N AND E WITH DRY
WEATHER AND SEASONABLE THROUGH THE WEEKEND.
WAA ENSUES EARLY NEXT WEEK WITH H85 TEMPS RISING INTO THE UPPER
TEENS ON MON RESULTING IN TEMPS RISING A FEW DEGREES ABOVE NORMAL
LEVELS MON. PRE-FRONTAL TROUGH MAY TRIGGER ISOLD-SCT STORMS MON AFTN
AS COLD FRONT APPROACHES FROM THE NW. TYPICAL GFS IS FASTER THAN THE
EC WITH THE FROPA SO HAVE COMPROMISED THE TIMING WITH IT COMING
THROUGH TUE MORNING. DRY AND SEASONABLE WEATHER COURTESY OF HIGH
PRES THEN BUILDS BACK IN OVER THE AREA.
&&
.AVIATION /08Z WEDNESDAY THROUGH SUNDAY/...
A TROUGH OF LOW PRESSURE WILL REMAIN IN THE VICINITY INTO WEDNESDAY
MORNING...THEN A COLD FRONT MOVES INTO THE TERMINALS DURING THE
AFTERNOON...MOVING SOUTH WEDNESDAY EVENING.
MAINLY VFR OUTSIDE OF TSTMS...ALTHOUGH HZ MAY RESTRICT VSBY TO
AROUND 6SM. OCCASIONAL GUSTY SW WINDS AT NYC/NJ TERMINALS FROM MID
MORNING ON.
THUNDERSTORMS WILL BECOME LIKELY BY EARLY AFTERNOON AND CONTINUE
INTO THE EARLY EVENING...WITH THE THREAT OF GUSTY WINDS...HAIL
AND HEAVY RAINFALL. CONVECTION EXPECTED TO TAPER AND WEAKEN DURING
THROUGH THE EVENING HOURS.
OUTLOOK FOR 06Z THURSDAY THROUGH SUNDAY...
.LATE TONIGHT...MAINLY VFR...EXCEPT PATCHY GROUND FOG ACROSS
OUTLYING TERMINALS.
.THURSDAY-THURSDAY EVENING...VFR. SCATTERED SHOWERS POSSIBLE.
.LATE THURSDAY NIGHT-SATURDAY MORNING...CEILINGS 1500 FT TO 2500 FT
POSSIBLE...BEST CHANCE AT SOUTHERN/COASTAL TERMINALS.
.SATURDAY AFTERNOON-SUNDAY...VFR.
&&
.MARINE...
MARGINAL SCA CONDITIONS ARE POSSIBLE ACROSS OCEAN WATERS LATER
TODAY AND TONIGHT. HOWEVER...KEPT SEAS BELOW 5 FT SINCE WAVEWATCH
INITIALLY ABOUT A FOOT TOO HIGH. SUB SCA EXPECTED ON THURSDAY AND
THURSDAY NIGHT.
MARGINAL SCA CONDS ARE POSSIBLE ON THE OCEAN WATERS FRI/FRI NIGHT
WITH AN INCREASING EASTERLY FLOW BETWEEN HIGH PRES BUILDING IN FROM
THE N AND LOW PRES PASSING TO THE S. A RELATIVELY LIGHT SE-S FLOW
WILL THEN PREVAIL WITH SUB-ADVSY CONDS THEREAFTER. HAVE CUT A FT OFF
OF WAVEWATCH GUIDANCE THROUGH THE PERIOD AS IT CONTINUES TO RUN
HIGH.
&&
.HYDROLOGY...
NO PRECIPITATION IS EXPECTED INTO THIS MORNING.
FLASH FLOODING IS POSSIBLE WITH ANY TRAINING CONVECTION THIS
AFTERNOON AND EVENING AS PWATS INCREASE TO AROUND 2 INCHES AND
STEERING FLOW NEARLY ALIGNS WITH FRONTAL BOUNDARY. A BASIN AVERAGE
QPF OF AROUND 1/2 INCH IS POSSIBLE ACROSS THE AREA...WITH
LOCALIZED AMOUNTS IN EXCESS OF 2 INCHES POSSIBLE WITH ANY TRAINING
CONVECTION.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...HEAT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR NYZ072>075-176-
178.
HEAT ADVISORY FROM 10 AM THIS MORNING TO 6 PM EDT THIS EVENING
FOR NYZ071-078-080-177-179.
NJ... HEAT ADVISORY FROM 10 AM THIS MORNING TO 6 PM EDT THIS EVENING
FOR NJZ004-006-103>108.
MARINE...NONE.
&&
$$
SYNOPSIS...JM
NEAR TERM...JM
SHORT TERM...JM
LONG TERM...24
AVIATION...NV
MARINE...24/JM
HYDROLOGY...JM
AREA FORECAST DISCUSSION
NWS NEW YORK NY
424 AM EDT WED JUL 18 2012
.SYNOPSIS...
A SLOW MOVING COLD FRONT FROM THE NORTH WILL MOVE INTO THE REGION
THIS AFTERNOON AND SOUTH OF THE REGION LATE TONIGHT INTO THURSDAY.
THE FRONT WILL THEN STALL WITH A WEAK AREA OF LOW PRESSURE MOVING
ALONG IT. LOW PRESSURE PASSES TO THE SOUTH ON FRIDAY WITH HIGH
PRESSURE BUILDING IN FROM THE NORTH THROUGH THE WEEKEND. ANOTHER
COLD FRONT WILL TRACK ACROSS THE AREA ON TUE.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
OUTSIDE OF A FEW ISOLATED SHOWERS THIS MORNING FROM INTERACTION
BETWEEN LOW LEVEL JET AND APPROACHING MID LEVEL DISTURBANCE...DRY
WEATHER EXPECTED WITH RELATIVELY WARM CONDITIONS THIS MORNING.
A SLOW MOVING COLD FRONT FROM THE NORTH WILL MOVE INTO THE REGION
THIS AFTERNOON. WITH THE REGION BEING ON THE NE EDGE OF A VERY HOT
AIRMASS...DAY START OUT VERY WARM AND LARGE CAPE IN THE 2000 TO
4000 J/KG RANGE IS EXPECTED TO BUILD WITH DIURNAL WARMING. SHEAR
OF 30 KT 0-6KM WITH WETBULB ZERO HEIGHTS OF 13-14 KFT. MENTIONED
GUSTY WINDS AND SMALL HAIL WITH SOME CELLS POSSIBLY GOING SEVERE.
BEFORE COVERAGE OF SHOWERS AND THUNDERSTORMS BECOMES WIDESPREAD...AT
LEAST SOUTHERN PORTIONS OF THE REGION WILL SEE ENOUGH SUN TO HAVE
HIGHS WELL INTO THE 90S AND WITH VERY MOIST AIRMASS CONVEYED BY
PWATS NEAR 2 INCHES AND DEWPOINTS IN THE LOWER 70S...HEAT INDICES
ARE EXPECTED TO BE NEAR 100 DEGREES FOR NEW YORK CITY AS WELL AS
URBAN SECTIONS OF SOUTHERN WESTCHESTER...MOST OF NE NJ AND WESTERN
LONG ISLAND.
FARTHER UP NORTH IN LOWER HUDSON VALLEY AND SOUTHERN CT WILL DEPEND
ON HOW FAST CONVECTION DEVELOPS AND THE INHERENT MITIGATION OF
DIURNAL WARMTH ASSOCIATED WITH EXPANDING CIRRUS CLOUD SHIELD OF
CONVECTION. RIGHT NOW...KEPT THEM LOWER WITHOUT HEAT ADVISORY BUT
HEAT INDICES ARE EXPECTED TO REACH MID TO UPPER 90S BEFORE
CONVECTION INCREASES SUBSTANTIALLY IN COVERAGE THIS AFTERNOON.
WILL START OFF THE HEAT ADVISORY LATE THIS MORNING BY 10 AM SINCE WE
WILL BE COMMENCING THE DIURNAL PERIOD AT A MUCH WARMER TEMPERATURE
THIS MORNING. MOST MODELS START TO BRING IN THE SHOWERS AND
THUNDERSTORMS BY 18Z ACROSS THE NORTHERN TIER AND BY 00Z ACROSS THE
ENTIRE AREA. ONLY EXCEPTION IF ECMWF WHICH HAS CONSISTENTLY HELD
BACK CONVECTION FOR LONG ISLAND UNTIL AFTER 00Z THU.
BASED ON MESOSCALE MODELS OF HRRR AND NSSL WRF...STRENGTHENING
CONVECTIVE CELLS START FIRING UP ALONG ACROSS THE ALLEGHENY PLATEAU
AND THE HUDSON VALLEY AROUND 17Z AFTER WHICH THEY WILL BE ON A
SOUTHEAST TRACK GOING INTO THE LOCAL FORECAST REGION. SHEAR OF 25
TO 30 KT FROM 0-6 KM WILL ALLOW FOR SOME THUNDERSTORMS TO PRODUCE
HAIL AND GUSTY WINDS. PWATS NEAR 2 INCHES SO HEAVY RAIN ALSO
POSSIBLE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/...
FOR TONIGHT...BETTER SHEAR ARRIVES WITH WINDS ALOFT AT 250MB
INCREASING AN EXTRA 10KT...PROMOTING GREATER DIVERGENCE. SOME
GREATER HEIGHT FALLS AT 500MB WILL ALSO IMPLY SOME GREATER SYNOPTIC
FORCING. THEREFORE EVEN THOUGH CAPE WILL BE ON A LOWERING
TREND...SOME THUNDERSTORMS WILL STILL MAINTAIN STRONG INTENSITIES
WITH HEAVY RAIN ALSO STILL POSSIBLE.
THE FRONT MOVES THROUGH LATE IN THE EVENING AND THEN SOUTH OF LONG
ISLAND GOING INTO THURSDAY. THE FRONT STALLS WITH A WEAK AREA OF LOW
PRESSURE MOVING IT. SOUTHERN PORTIONS OF THE FORECAST AREA COULD SEE
SOME SHOWERS FROM TIME TO TIME ON THURSDAY AS A RESULT. IN THE UPPER
LEVELS AT 500MB...THE AREA WILL BE IN A NW FLOW WITH A LONGWAVE
TROUGH SETTING UP ACROSS THE NORTHEAST. WENT WITH MORE OF THE COOLER
GUIDANCE FOR HIGHS CONSIDERING THE MORE EASTERLY FLOW. NOT EXPECTING
ANY THUNDERSTORMS WITH THIS ACTIVITY WITH MORE STABLE SFC CONDITIONS
FORECAST.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
A MEAN TROUGH WILL REMAIN OVER THE NE CONUS THROUGH THE PERIOD WHILE
A PERSISTENT AND STRONG RIDGE ALOFT REMAINS ENTRENCHED OVER THE
PLAINS AND ROCKIES.
COLD FRONT SLOWLY PRESSES SOUTHWARD THROUGH THE MID ATLANTIC STATES
THROUGH FRIDAY WITH CANADIAN HIGH PRES BUILDING IN FROM THE N. AN
AREA OF LOW PRES IS FORECAST TO DEVELOP ON THE FRONT THU NIGHT AND
PASS TO THE S FRI MORNING WITH AN UPPER LEVEL TROUGH SWINGING
THROUGH ALOFT. AN EASTERLY FLOW WILL MOISTEN LOW LEVELS WITH THE CHC
OF SHOWERS ON FRI. MODELS HAVE BEEN CONSISTENT WITH THIS FOR THE
LAST DAY...SO HAVE ADDED CHC POPS TO THE FORECAST. ABUNDANT CLOUD
COVER AND ONSHORE FLOW WILL RESULT IN A MUCH COOLER DAY ACROSS THE
AREA WITH HIGHS ONLY EXPECTED TO REACH THE UPPER 70S AT MOST
LOCATIONS. AS THE FRONT SINKS FURTHER S LATER FRI AND FRI NIGHT
DRIER AND MORE STABLE AIR WILL WORK IN FROM THE N AND E WITH DRY
WEATHER AND SEASONABLE THROUGH THE WEEKEND.
WAA ENSUES EARLY NEXT WEEK WITH H85 TEMPS RISING INTO THE UPPER
TEENS ON MON RESULTING IN TEMPS RISING A FEW DEGREES ABOVE NORMAL
LEVELS MON. PRE-FRONTAL TROUGH MAY TRIGGER ISOLD-SCT STORMS MON AFTN
AS COLD FRONT APPROACHES FROM THE NW. TYPICAL GFS IS FASTER THAN THE
EC WITH THE FROPA SO HAVE COMPROMISED THE TIMING WITH IT COMING
THROUGH TUE MORNING. DRY AND SEASONABLE WEATHER COURTESY OF HIGH
PRES THEN BUILDS BACK IN OVER THE AREA.
&&
.AVIATION /08Z WEDNESDAY THROUGH SUNDAY/...
A TROUGH OF LOW PRESSURE WILL REMAIN IN THE VICINITY INTO WEDNESDAY
MORNING...THEN A COLD FRONT MOVES INTO THE TERMINALS DURING THE
AFTERNOON...MOVING SOUTH WEDNESDAY EVENING.
MAINLY VFR OUTSIDE OF TSTMS...ALTHOUGH HZ MAY RESTRICT VSBY TO
AROUND 6SM. OCCASIONAL GUSTY SW WINDS AT NYC/NJ TERMINALS FROM MID
MORNING ON.
THUNDERSTORMS WILL BECOME LIKELY BY EARLY AFTERNOON AND CONTINUE
INTO THE EARLY EVENING...WITH THE THREAT OF GUSTY WINDS...HAIL
AND HEAVY RAINFALL. CONVECTION EXPECTED TO TAPER AND WEAKEN DURING
THROUGH THE EVENING HOURS.
OUTLOOK FOR 06Z THURSDAY THROUGH SUNDAY...
.LATE TONIGHT...MAINLY VFR...EXCEPT PATCHY GROUND FOG ACROSS
OUTLYING TERMINALS.
.THURSDAY-THURSDAY EVENING...VFR. SCATTERED SHOWERS POSSIBLE.
.LATE THURSDAY NIGHT-SATURDAY MORNING...CEILINGS 1500 FT TO 2500 FT
POSSIBLE...BEST CHANCE AT SOUTHERN/COASTAL TERMINALS.
.SATURDAY AFTERNOON-SUNDAY...VFR.
&&
.MARINE...
MARGINAL SCA CONDITIONS ARE POSSIBLE ACROSS OCEAN WATERS LATER
TODAY AND TONIGHT. HOWEVER...KEPT SEAS BELOW 5 FT SINCE WAVEWATCH
INITIALLY ABOUT A FOOT TOO HIGH. SUB SCA EXPECTED ON THURSDAY AND
THURSDAY NIGHT.
MARGINAL SCA CONDS ARE POSSIBLE ON THE OCEAN WATERS FRI/FRI NIGHT
WITH AN INCREASING EASTERLY FLOW BETWEEN HIGH PRES BUILDING IN FROM
THE N AND LOW PRES PASSING TO THE S. A RELATIVELY LIGHT SE-S FLOW
WILL THEN PREVAIL WITH SUB-ADVSY CONDS THEREAFTER. HAVE CUT A FT OFF
OF WAVEWATCH GUIDANCE THROUGH THE PERIOD AS IT CONTINUES TO RUN
HIGH.
&&
.HYDROLOGY...
NO PRECIPITATION IS EXPECTED INTO THIS MORNING.
FLASH FLOODING IS POSSIBLE WITH ANY TRAINING CONVECTION THIS
AFTERNOON AND EVENING AS PWATS INCREASE TO AROUND 2 INCHES AND
STEERING FLOW NEARLY ALIGNS WITH FRONTAL BOUNDARY. A BASIN AVERAGE
QPF OF AROUND 1/2 INCH IS POSSIBLE ACROSS THE AREA...WITH
LOCALIZED AMOUNTS IN EXCESS OF 2 INCHES POSSIBLE WITH ANY TRAINING
CONVECTION.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...HEAT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR NYZ072>075-176-
178.
HEAT ADVISORY FROM 10 AM THIS MORNING TO 6 PM EDT THIS EVENING
FOR NYZ071-078-080-177-179.
NJ... HEAT ADVISORY FROM 10 AM THIS MORNING TO 6 PM EDT THIS EVENING
FOR NJZ004-006-103>108.
MARINE...NONE.
&&
$$
SYNOPSIS...JM
NEAR TERM...JM
SHORT TERM...JM
LONG TERM...24
AVIATION...NV
MARINE...24/JM
HYDROLOGY...JM
AREA FORECAST DISCUSSION
NWS ALBANY NY
411 AM EDT WED JUL 18 2012
.SYNOPSIS...
A COLD FRONT WILL SLOWLY MOVE SOUTHWARD ACROSS EASTERN NEW YORK AND
WESTERN NEW ENGLAND TODAY WITH SOME SHOWERS AND THUNDERSTORMS. A
BROAD AREA OF HIGH PRESSURE WILL BUILD IN FROM JAMES BAY TONIGHT
INTO THURSDAY WITH SEASONABLE TEMPERATURES AND LESS HUMID
CONDITIONS. A DISTURBANCE MOVING ALONG THE OLD FRONTAL BOUNDARY
OVER THE UPPER MID ATLANTIC REGION MAY BRING A FEW SHOWERS TO
LOCATIONS SOUTH OF THE CAPITAL REGION THURSDAY NIGHT INTO FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 4 AM EDT...ONE MORE HUMID DAY IS EXPECTED ACROSS ERN NY AND
WRN NEW ENGLAND...AS RELIEF IS ON THE WAY WITH A COLD FRONT SLOWLY
MOVING S/SE FROM THE ST LAWRENCE RIVER VALLEY THIS MORNING. A
MOIST AIR MASS IS IN PLACE WITH SFC DEWPTS IN THE M60S TO L70S
OVER THE FCST AREA. A LULL IN THE CONVECTIVE ACTIVITY HAS OCCURRED
OVER THE PAST FEW HOURS...BUT CONVECTIVE INITIATION SHOULD
INCREASE QUICKLY IN THE LATE MORNING AND EARLY PM.
GENERAL THINKING HAS NOT CHANGED TOO MUCH WITH THE BEST DEEP SHEAR
AND INSTABILITY COMPOSITE OVERLAYS FROM THE NAM/GFS FOR LOCATIONS
JUST SOUTH AND EAST OF THE CAPITAL DISTRICT FOR POSSIBLE SVR WX TODAY.
CAUTION HAS TOO BE USED WITH THE GFS INSTABILITY CHARTS...AS SFC
DEWPTS ARE WELL INTO THE M70S OVER A LARGE CHUNK OF THE AREA SOUTH
OF ALBANY. A CORRECTION TO U60S TO L70S STILL YIELDS SBCAPE VALUES
IN THE 1000-2000 J/KG WITH SLIGHTLY HIGHER AMOUNTS. THE DEEP SHEAR
VALUES ARE ON THE NORTH SIDE OF THE BOUNDARY WITH 45-60
KTS. HOWEVER...0-6 KM BULK SHEAR VALUES ON THE NAM/GFS ARE STILL
30-40 KT FROM ALY SOUTH AND EAST. THERE MAY BE ENOUGH CONVERGENCE
AND LIFT WITH THE BOUNDARY FOR A FEW STRONG TO SEVERE STORMS. WE
ARE GOING TO DEVIATE SLIGHTLY FROM THE LATEST DAY 1 GRAPHIC...AND
FOCUS ON THE SEVERE THREAT FOR MAINLY THE ERN CATSKILLS...MID
HUDSON VALLEY...CNTRL AND SRN TACONICS...BERKSHIRES...AND NW CT.
THE COUNTIES WE WILL HIGHLIGHT IN THE HWO WILL BE
GREENE...ULSTER...COLUMBIA...DUTCHESS...BERKSHIRE...AND
LITCHFIELD.
PWAT VALUES WILL STILL BE IN THE 1.50-2.00 INCH RANGE FROM THE
CAPITAL REGION...MOHAWK VALLEY SOUTH AND EAST. SOME LOCALLY HEAVY
DOWNPOURS WILL BE POSSIBLE...AND SOME LOCATIONS COULD GET A QUICK
INCH OR TWO OF RAIN. FLASH FLOODING IS NOT EXPECTED. ALSO...THE
STRONG FLOW ALOFT SHOULD CONTINUE TO MOVE THE CONVECTION ALONG
DURING THE DAY.
CONVECTIVE INITIATION SHOULD OCCUR QUICKER TODAY WITH AN ERODING
CAP...AND THE CLOSER PROXIMITY OF THE FRONTAL BOUNDARY. THE
THUNDERSTORMS SHOULD POP UP AS SOON AS THE LATE MORNING IN THE
CNTRL-NRN PORTIONS OF CWA...AND SPREAD SOUTH OF ALY. WE KEPT THE
HIGHEST CHC TO LIKELY POPS FROM ALY SOUTH AND EAST DURING THE AFTERNOON.
HEAT INDICES/APPARENT TEMPS WILL GET INTO THE MID AND U90S OVER
PORTIONS OF THE MID HUDSON VALLEY...AND LITCHFIELD COUNTY...BUT
THEY SHOULD FALL SHY OF ADVISORY LEVELS WITH THE SHOWERS AND
THUNDERSTORMS MOVING IN. LATEST HIRES WRF HAS THE MOST ROBUST
CONVECTION WITH THE COMPOSITE REF PRODUCT GRAZING SRN DUTCHESS...AND
LITCHFIELD COUNTIES AFTER 21Z...THE LATEST HRRR IS A LITTLE BIT
FURTHER NORTH...BUT STILL SOUTH OF THE CAPITAL REGION...BUT HAS
THE STRONGER CONVECTION IMPACTING THE AREA BTWN 18Z-21Z. DAMAGING
WIND GUSTS WOULD BE THE MAIN THREAT WITH POTENTIAL BOWING SEGMENTS
WITH UNIDIRECTIONAL SHEAR PROFILES ON THE MODEL SOUNDINGS.
MAX TEMPS WILL RANGE FROM THE M80S TO L90S IN THE VALLEYS...WITH
SOME U70S OVER THE NRN MTNS TO LOWER TO MID80S OVER THE HILLS AND
MTNS SOUTH OF ALBANY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
TONIGHT...THE FRONT DIPS SOUTH OF THE FORECAST AREA WITH THE ISOLD-
SCT SHOWER AND THUNDERSTORM ACTIVITY ENDING BY AROUND MIDNIGHT FOR
THE SRN MOST ZONES. THE LOW LEVEL COLD ADVECTION WILL ALLOW H850
TEMPS TO LOWER TO 10 TO 14C FROM THE CAPITAL REGION NORTH AND
WEST...AND 14-17C TO THE SOUTH AND EAST. THE SKIES SHOULD CLEAR
OVERNIGHT...AND LOWS WILL BE IN THE U40S TO M50S NORTH OF
ALY...AND U50S TO L60S SOUTH AND EAST.
THURSDAY...A VERY NICE DAY IS SHAPING UP WITH STRONG SUBSIDENCE
IN WAKE OF THE FRONT...AND A LARGE SFC ANTICYCLONE BUILDING IN
FROM ONTARIO AND JAMES BAY. FEW-SCT FAIR WX CUMULUS WILL BE
AROUND...AND DECENT MIXING WILL ALLOW MAX TEMPS TO BE IN THE LOWER
TO M80S IN THE VALLEYS...AND MAINLY 70S OVER THE HILLS AND MTNS
/SOME U60S TOO/.
THURSDAY NIGHT...H500 UPPER LOW CONTINUES TO LIFT N/NE INTO THE
CANADIAN MARITIMES WITH BROAD SFC HIGH CONTINUING TO RIDGE IN FROM
JAMES BAY. FRONTAL BOUNDARY FROM WED...BECOMES STATIONARY OVER THE
MID ATLANTIC REGION. THE NAM/GFS/ECMWF/CAN GUIDANCE ALL SHOW A
DISTURBANCE MOVING ALONG THE BOUNDARY...WITH SOME THERMAL
ADVECTION SHOWERS GETTING INTO THE MID HUDSON VALLEY. WE PLACED
SOME SLIGHT CHC POPS FOR SHOWERS WELL SOUTH OF THE CAPITAL
REGION...OTHERWISE IT SHOULD BE A COOL AND COMFORTABLE EVENING
WITH LOWS IN THE 50S...EXCEPT FOR SOME 40S OVER THE SRN
DACKS...AND SRN GREENS...AND SOME L60S OVER THE MID HUDSON VALLEY.
FRI-FRI NIGHT...CLOUDS CONTINUE TO SPILL NORTH WITH THE WAVE
RIDING THE FRONTAL BOUNDARY OVER THE MID ATLANTIC REGION. THE SREF
POPS STILL REMAIN LOW IN THE SLIGHT CHC CATEGORY. WEAK THETA-E
ADVECTION AND ISENTROPIC LIFT COULD ALLOW A FEW-SCT SHOWERS SOUTH
OF THE CAPITAL REGION. MAX TEMPS WILL ACTUALLY BE WARMER FROM THE
CAPITAL REGION NORTH...WHERE MORE SUNSHINE MAY OCCUR. THE CLOUDS
AND ISOLD-SCT SHOWERS SHOULD CLEAR FRI NIGHT...AS THE SFC RIDGE
BUILDS BACK IN. TEMPS MAY ACTUALLY RUN A SHADE BELOW NORMAL THIS
DAY.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
THE LONG TERM PERIOD IS EXPECTED TO START DRY WITH THE POSSIBILITY
OF SOME UNSETTLED WEATHER LATE IN THE WEEKEND INTO EARLY NEXT WEEK.
TEMPS AND HUMIDITY WILL START TO INCREASE SLOWLY AS THE RIDGE OF
HIGH PRESSURE SLIDES OFF THE EASTERN SEABOARD AND A RETURN FLOW
STARTS TO DEVELOP. DRY WEATHER IS EXPECTED TO CONTINUE THROUGH
SUNDAY MORNING WITH WIDELY SCATTERED TO SCATTERED SHOWERS DEVELOPING
SUNDAY AFTERNOON AND CONTINUING INTO SUNDAY EVENING AS A COLD FRONT
DROPS SOUTHEAST TOWARD THE SAINT LAWRENCE VALLEY. EXPECT A BETTER
CHANCE OF SHOWERS AND THUNDERSTORMS MONDAY INTO MONDAY EVENING AS
THE COLD FRONT WORKS SOUTHEASTWARD THROUGH THE FA ENDING UP ACROSS
SOUTHEAST NY AND SOUTHERN NEW ENGLAND TUESDAY MORNING.
H8 TEMPS ARE EXPECTED TO RISE FROM +10 TO +11 C SATURDAY MORNING TO
+15 TO +17 C LATE SUNDAY AHEAD OF THE COLD FRONT AND THEN DROP TO
+10 TO +14 C BY LATE TUESDAY IN THE WAKE OF THE COLD FRONT.
EXPECT HIGHS ON SATURDAY TO BE IN THE MID 70S TO LOWER 80S...UPPER
70S TO MID 80S ON SUNDAY AND MONDAY...AND LOWER 70S TO MID 80S ON
TUESDAY. LOWS ARE GENERALLY EXPECTED TO BE IN THE MID 50S TO MID
60S...SATURDAY NIGHT THROUGH MONDAY NIGHT.
&&
.AVIATION /07Z WEDNESDAY THROUGH SUNDAY/...
MOST OF THE CONVECTION FOR THE TAF SITES HAS ENDED FOR THE NIGHT
EXCEPT AT KGFL WHERE ONE LAST ROUND OF SHOWERS AND THUNDERSTORMS
IS EXPECTED TO MOVE THROUGH BTWN 06Z AND 08Z. IT WILL CONTINUE TO
REMAIN VERY HUMID OVERNIGHT WITH MAINLY VFR/MVFR CONDITIONS WITH
SOME FOG AND HAZE MAINLY AFTER 08Z. FOR TODAY...EXPECT BEST CHANCE
OF SHOWERS AND THUNDERSTORMS WILL BE ACROSS SOUTHERN AREAS AHEAD
OF THE COLD FRONT WITH CLEARING EXPECTED AT THE TAF SITES DURING
THE EVENING.
LIGHT AND VARIABLE WINDS OVERNIGHT WILL BECOME WEST TO NORTHWEST
TODAY AND THEN EVENTUALLY NORTHWEST TO NORTH AT 5 TO 10 KTS IN THE
WAKE OF THE COLD FRONT. THE EXCEPTION WILL BE AT KPOU WHERE
SOUTHWEST WINDS AT 4-6 KTS THROUGH THIS AFTERNOON WILL BECOME
NORTH AT AROUND 3 KTS EARLY THIS EVENING. WINDS AT ALL THE TAF
SITES WILL THEN BECOME LIGHT AND VARIABLE BY MID TO LATE EVENING.
OUTLOOK...
THU..NO SIG WX.
FRI-SUN...VFR...SLIGHT CHC ISOLD AFTERNOON TSTMS.
&&
.FIRE WEATHER...
A COLD FRONT WILL SLOWLY MOVE SOUTHWARD ACROSS EASTERN NEW YORK AND
WESTERN NEW ENGLAND TODAY WITH SOME SHOWERS AND THUNDERSTORMS. A
BROAD AREA OF HIGH PRESSURE WILL BUILD IN FROM JAMES BAY TONIGHT
INTO THURSDAY WITH SEASONABLE TEMPERATURES AND LESS HUMID
CONDITIONS.
RELATIVE HUMIDITY VALUES WILL LOWER TO 40-70 PERCENT TODAY...AND
RECOVER TO 90 TO 100 PERCENT TONIGHT. EXPECT MINIMUM RH VALUES OF
25 TO 50 PERCENT THURSDAY AFTERNOON.
THE WINDS WILL BE FROM THE WEST OR NORTHWEST AT 5 TO 15 MPH
TODAY...AND DECREASE TO LESS THAN 10 MPH TONIGHT. NORTH WINDS OF 5
TO 15 MPH WILL BE COMMON ON THURSDAY.
&&
.HYDROLOGY...
NO HYDRO PROBLEMS ARE EXPECTED ON THE MAIN STEM RIVERS OVER THE
NEXT 5 DAYS.
SHOWERS AND THUNDERSTORMS ASSOCIATED WITH A FRONTAL PASSAGE
TODAY WILL PRODUCE SOME HEAVY RAINFALL DUE TO A SHORT PERIOD OF
ANOMALOUSLY HIGH PRECIPITATELY WATER VALUES IN THE 1.5 TO 2 INCH
RANGE. SOME PONDING OF WATER ON ROADWAYS OR POOR DRAINAGE FLOODING
IS POSSIBLE ESPECIALLY FROM THE CAPITAL REGION SOUTH. ZONAL FLASH FLOOD
GUIDANCE VALUES REMAIN HIGH FOR MID JULY. THE POTENTIAL FOR FLASH
FLOODING IS LOW AT THIS TIME IN THE ALY HYDRO SERVICE AREA.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING
OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE
VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON
OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...WASULA
NEAR TERM...WASULA
SHORT TERM...WASULA
LONG TERM...11
AVIATION...11
FIRE WEATHER...WASULA
HYDROLOGY...WASULA
AREA FORECAST DISCUSSION...RESENT
NWS TAMPA BAY RUSKIN FL
417 AM EDT WED JUL 18 2012
.SYNOPSIS...
07Z WATER VAPOR AND H4 RUC ANALYSIS CONTINUES TO SHOW OUR REGION
LOCATED WITHIN AN UPPER LEVEL WEAKNESS BETWEEN A RIDGE OF HIGH
PRESSURE OVER THE LOWER/MIDDLE MS VALLEY...AND ANOTHER RIDGE CENTER
OFF THE SOUTHEAST CONUS COAST. THE WEAKNESS IS DOMINATED BY A
STUBBORN TUTT CELL WHICH IS VERY SLOWLY MIGRATING NORTHWARD INTO
SOUTHERN GEORGIA EARLY THIS MORNING. OUR FORECAST AREA (ESPECIALLY
THE NORTHERN ZONES) REMAIN UNDER THE SOUTHERN PERIPHERY OF THIS
CIRCULATION ALONG WITH PERIODIC IMPULSES OF SYNOPTIC SUPPORT FOR
ENHANCED LIFT. THE ATMOSPHERIC COLUMN WITHIN THIS WEAKNESS IS RATHER
MOIST WITH PW VALUES OF 2"+.
AT THE SURFACE...SUBTROPICAL RIDGE AXIS REMAINS ALIGNED OVER THE
SOUTHERN HALF OF THE FL PENINSULA INTO THE SE GULF OF MEXICO. A
FAVORED SW FLOW AROUND THIS RIDGE ALONG WITH SOME ENHANCED SUPPORT
FROM THE UPPER TUTT CELL IS FORCING A SCATTERING OF CONVECTION EARLY
THIS MORNING OVER THE NORTHERN AND CENTRAL COASTAL WATERS. THE
1000-700MB FLOW TO THE NORTH OF TAMPA BAY IS HELPING TO MIGRATE SOME
OF THIS ACTIVITY BACK TOWARD THE NATURE COAST. WILL KEEP SCT SHOWERS
IN THE FORECAST ALONG THE COAST FROM PINELLAS NORTHWARD.
FURTHER SOUTH...THE INFLUENCE OF THE UPPER TUTT IS MUCH LESS. THIS
TIME OF YEAR THE UNSTABLE LOWER LEVELS OVER THE GULF COMBINED WITH
ANY LATE NIGHT OFFSHORE WIND COMPONENT MAY STILL FIRE A FEW STORMS
OVER THE SOUTHERN COASTAL WATERS...HOWEVER A LOW LEVEL FLOW MORE
PARALLEL TO THE COAST SHOULD KEEP MOST OF THIS POTENTIAL ACTIVITY
FROM MIGRATING BACK TO THE BEACHES.
&&
.SHORT TERM (TODAY THROUGH FRIDAY)...
TODAY...UPPER LEVEL WEAKNESS/TUTT CELL IS PROGGED TO OPEN UP AND
CONTINUE TO SLOWLY LIFT NORTH. THIS PROGRESSION WILL ALLOW THE UPPER
RIDGE TO OUR EAST TO BEGIN BUILDING BACK TOWARD THE REGION. OVERALL
WILL SEE A SLOW RISE IN H5 HEIGHTS THROUGH THE DAY...HOWEVER THE
RIDGE AXIS AND ANY SIGNIFICANT SUPPRESSION WILL REMAIN WELL TO OUR
SOUTH. WITH A MOIST COLUMN IN PLACE...WILL EXPECT AT LEAST A CLIMO
DISTRIBUTION OF SHOWERS AND STORMS THROUGH THE DAY. HIGHEST COVERAGE
OF SHOWERS LIKELY TO OCCUR ALONG AND NORTH OF THE I-4 CORRIDOR IN
CLOSER PROXIMITY TO CYCLONIC FLOW/SYNOPTIC SUPPORT ASSOCIATED WITH
THE DEPARTING TUTT. SOUTH OF THE TAMPA BAY AREA ALONG THE
COAST...SHOULD SEE A DECENT SEA-BREEZE CIRCULATION DEVELOP AND HELP
TO PUSH MUCH OF THE DIURNAL CONVECTION INLAND FROM THE BEACHES AFTER
THE MIDDLE AFTERNOON HOURS.
TONIGHT...UPPER LEVEL RIDGING WILL CONTINUE TO BUILD INTO MAINLY THE
CENTRAL AND SOUTHERN PORTIONS OF THE PENINSULA...WITH A DRIER AND
MORE HOSTILE COLUMN FOR DEEP CONVECTION BEGINNING TO ARRIVE FROM THE
SOUTH AND SOUTHEAST. UPPER LEVEL WEAKNESS/TROUGHING WILL BASICALLY
STALL UP OVER THE FL PANHANDLE REGION...AND THEN REMAIN IN POSITION
THROUGH THE REMAINDER OF THE SHORT TERM PERIOD. THIS PATTERN WILL
PUT OUR NORTHERN ZONES (NATURE COAST) IN THE TRANSITION ZONES
BETWEEN THE LESS FAVORABLE CONVECTIVE REGIME TO THE SOUTH AND A VERY
FAVORABLE CONVECTIVE REGIME NORTH AND WEST OF THE SUWANNEE RIVER
VALLEY. WITH THIS IN MIND WILL ONCE AGAIN HIGHLIGHT NOCTURNAL
SHOWERS/STORMS DEVELOPING OVER THE NORTHERN COASTAL WATERS...THEN
MIGRATING BACK TOWARD THE COAST DURING THE LATE NIGHT HOURS. BEST
CHANCES TO SEE THIS LATE NIGHT CONVECTION WILL BE ALONG COASTAL
LEVY/CITRUS COUNTIES.
THURSDAY...UPPER RIDGE AXIS AND ENHANCED SUPPRESSION WILL CONTINUE
OVER THE SOUTHERN HALF OF THE AREA. WILL KEEP THE HIGHEST RAIN
CHANCES (35-50%) ALONG AND NORTH OF THE I-4 CORRIDOR...AND THE
HIGHEST TEMPERATURES (MIDDLE 90S) FURTHER SOUTH. FROM THE TAMPA BAY
AREA AND SOUTHWARD...GOOD CHANCE TO SEE THE SEA-BREEZE CLEAR OUT ANY
WIDELY SCT SHOWERS FROM THE BEACHES BY MID-AFTERNOON.
FRIDAY...LOOKS TO BE THE LEAST ACTIVE DAY OF THE WORK WEEK IN TERMS
OF CONVECTION. WILL HIGHLIGHT A 30% CHANCE FOR WIDELY SCT STORMS
OVER THE FAR NORTHERN ZONES TOWARD THE SUWANNEE RIVER VALLEY...WITH
ONLY ISOLATED 20% SHOWERS FOR THE MAJORITY OF THE AREA. WITH BOTH
THE UPPER AND SURFACE RIDGE AXIS LIFTING NORTH OF THE FORT MYERS
AREA...WOULD NOT BE SURPRISED TO SEE A BIT BETTER CHANCE FOR LATE
DAY STORMS DOWN TOWARD CHARLOTTE/LEE COUNTIES...BUT WILL ONLY
HIGHLIGHT A 30% CHANCE FOR NOW. THE BIGGER STORY FOR FRIDAY WILL BE
THE TEMPERATURES. MANY LOCATIONS AWAY FROM THE BEACHES WILL SEE THE
MERCURY SOAR INTO THE MIDDLE 90S...WITH NORMALLY HOTTER LOCATIONS OF
HARDEE/DE SOTO/HIGHLANDS COUNTIES REACHING THE UPPER 90S.
&&
.LONG TERM (SATURDAY THROUGH NEXT WEDNESDAY)...
OVERALL THE GLOBAL MODELS HAVE NOT CHANGED MUCH. A STRONG
SUB-TROPICAL RIDGE WILL STRETCH WESTWARD FROM THE ATLANTIC TO
CENTRAL FLORIDA THROUGH THE PERIOD. THE DRIER AIR WILL BE RETREATING
NORTHWARD FRIDAY NIGHT WITH HIGHER PRECIPITABLE WATERS RETURNING
FROM SOUTH TO NORTH ON SATURDAY. ONCE AGAIN MEX POPS ARE QUITE
LOW...SO WILL CONTINUE TO JUST SHOW A SLIGHT CHANCE OF AFTERNOON
STORMS ON SATURDAY.
ON SUNDAY...PRECIPITABLE WATERS RISE TO WELL OVER 2 INCHES FOLLOWING
A THE PASSAGE OF A WEAK TROPICAL WAVE. THIS SHOULD ALLOW RAIN
CHANCES TO RETURN TO NORMAL WITH 40 TO 50 PERCENT CHANCES DURING THE
AFTERNOON HOURS.
DRY AIR BEGINS TO MOVE BACK IN FROM THE SOUTH ON MONDAY WITH RAIN
CHANCES DECREASING TO ONLY 20 TO 30 PERCENT AGAIN BY TUESDAY.
IT WILL BE QUITE HOT ON SATURDAY WITH WIDESPREAD MID 90S LIKELY AWAY
FROM THE COAST. ADDITIONAL CLOUD COVER AND SHOWER ACTIVITY WILL KEEP
IT A COUPLE OF DEGREES COOLER ON SUNDAY...THEN THE MID 90S RETURN
AGAIN WITH THE DRIER AIR IN PLACE BY TUESDAY.
&&
.AVIATION...
MAINLY VFR CONDITIONS EXPECTED THROUGH MID-MORNING WEDNESDAY WITH
SOME MVFR OR IFR CONDITIONS POSSIBLE 15Z TO 00Z AS SHOWERS AND
THUNDERSTORMS REDEVELOP WITH HEATING. COVERAGE AND TIMING OF SHOWERS
STILL NOT CERTAIN SO WILL HANDLE WITH VCTS AT THIS TIME.
&&
.MARINE...
THE SUBTROPICAL RIDGE AXIS WILL REMAIN ALIGNED OVER THE SOUTHERN AND
CENTRAL WATERS THROUGH THE NEXT SEVERAL DAYS. THIS POSITION WILL
KEEP WINDS AND SEAS BELOW HEADLINE CRITERIA INTO THE UPCOMING
WEEKEND. THE BEST CHANCES FOR SCATTERED SHOWERS AND STORMS OVER THE
COASTAL WATERS WILL BE FROM TAMPA BAY NORTHWARD ALONG THE NATURE
COAST.
&&
.FIRE WEATHER...
NO SIGNIFICANT FIRE WEATHER CONCERNS ANTICIPATED THROUGH FRIDAY.
ALTHOUGH TEMPERATURES WILL BE INCREASING EACH AFTERNOON FOR THE NEXT
SEVERAL DAYS...RELATIVE HUMIDITY LEVELS ARE STILL FORECAST TO
GENERALLY REMAIN ABOVE CRITICAL VALUES.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 88 77 92 78 / 50 20 20 10
FMY 91 76 93 76 / 30 20 20 10
GIF 91 76 95 75 / 50 30 40 20
SRQ 89 76 91 76 / 50 20 20 10
BKV 90 72 93 73 / 60 20 30 10
SPG 88 78 91 80 / 50 20 20 10
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
SYNOPSIS/SHORT TERM/MARINE/FIRE WX...MROCZKA
AVIATION/LONG TERM...JILLSON
AREA FORECAST DISCUSSION...RESENT
NWS TAMPA BAY RUSKIN FL
340 AM EDT WED JUL 18 2012
.SYNOPSIS...
07Z WATER VAPOR AND H4 RUC ANALYSIS CONTINUES TO SHOW OUR REGION
LOCATED WITHIN AN UPPER LEVEL WEAKNESS BETWEEN A RIDGE OF HIGH
PRESSURE OVER THE LOWER/MIDDLE MS VALLEY...AND ANOTHER RIDGE CENTER
OFF THE SOUTHEAST CONUS COAST. THE WEAKNESS IS DOMINATED BY A
STUBBORN TUTT CELL WHICH IS VERY SLOWLY MIGRATING NORTHWARD INTO
SOUTHERN GEORGIA EARLY THIS MORNING. OUR FORECAST AREA (ESPECIALLY
THE NORTHERN ZONES) REMAIN UNDER THE SOUTHERN PERIPHERY OF THIS
CIRCULATION ALONG WITH PERIODIC IMPULSES OF SYNOPTIC SUPPORT FOR
ENHANCED LIFT. THE ATMOSPHERIC COLUMN WITHIN THIS WEAKNESS IS RATHER
MOIST WITH PW VALUES OF 2"+.
AT THE SURFACE...SUBTROPICAL RIDGE AXIS REMAINS ALIGNED OVER THE
SOUTHERN HALF OF THE FL PENINSULA INTO THE SE GULF OF MEXICO. A
FAVORED SW FLOW AROUND THIS RIDGE ALONG WITH SOME ENHANCED SUPPORT
FROM THE UPPER TUTT CELL IS FORCING A SCATTERING OF CONVECTION EARLY
THIS MORNING OVER THE NORTHERN AND CENTRAL COASTAL WATERS. THE
1000-700MB FLOW TO THE NORTH OF TAMPA BAY IS HELPING TO MIGRATE SOME
OF THIS ACTIVITY BACK TOWARD THE NATURE COAST. WILL KEEP SCT SHOWERS
IN THE FORECAST ALONG THE COAST FROM PINELLAS NORTHWARD.
FURTHER SOUTH...THE INFLUENCE OF THE UPPER TUTT IS MUCH LESS. THIS
TIME OF YEAR THE UNSTABLE LOWER LEVELS OVER THE GULF COMBINED WITH
ANY LATE NIGHT OFFSHORE WIND COMPONENT MAY STILL FIRE A FEW STORMS
OVER THE SOUTHERN COASTAL WATERS...HOWEVER A LOW LEVEL FLOW MORE
PARALLEL TO THE COAST SHOULD KEEP MOST OF THIS POTENTIAL ACTIVITY
FROM MIGRATING BACK TO THE BEACHES.
&&
.SHORT TERM (TODAY THROUGH FRIDAY)...
TODAY...UPPER LEVEL WEAKNESS/TUTT CELL IS PROGGED TO OPEN UP AND
CONTINUE TO SLOWLY LIFT NORTH. THIS PROGRESSION WILL ALLOW THE UPPER
RIDGE TO OUR EAST TO BEGIN BUILDING BACK TOWARD THE REGION. OVERALL
WILL SEE A SLOW RISE IN H5 HEIGHTS THROUGH THE DAY...HOWEVER THE
RIDGE AXIS AND ANY SIGNIFICANT SUPPRESSION WILL REMAIN WELL TO OUR
SOUTH. WITH A MOIST COLUMN IN PLACE...WILL EXPECT AT LEAST A CLIMO
DISTRIBUTION OF SHOWERS AND STORMS THROUGH THE DAY. HIGHEST COVERAGE
OF SHOWERS LIKELY TO OCCUR ALONG AND NORTH OF THE I-4 CORRIDOR IN
CLOSER PROXIMITY TO CYCLONIC FLOW/SYNOPTIC SUPPORT ASSOCIATED WITH
THE DEPARTING TUTT. SOUTH OF THE TAMPA BAY AREA ALONG THE
COAST...SHOULD SEE A DECENT SEA-BREEZE CIRCULATION DEVELOP AND HELP
TO PUSH MUCH OF THE DIURNAL CONVECTION INLAND FROM THE BEACHES AFTER
THE MIDDLE AFTERNOON HOURS.
TONIGHT...UPPER LEVEL RIDGING WILL CONTINUE TO BUILD INTO MAINLY THE
CENTRAL AND SOUTHERN PORTIONS OF THE PENINSULA...WITH A DRIER AND
MORE HOSTILE COLUMN FOR DEEP CONVECTION BEGINNING TO ARRIVE FROM THE
SOUTH AND SOUTHEAST. UPPER LEVEL WEAKNESS/TROUGHING WILL BASICALLY
STALL UP OVER THE FL PANHANDLE REGION...AND THEN REMAIN IN POSITION
THROUGH THE REMAINDER OF THE SHORT TERM PERIOD. THIS PATTERN WILL
PUT OUR NORTHERN ZONES (NATURE COAST) IN THE TRANSITION ZONES
BETWEEN THE LESS FAVORABLE CONVECTIVE REGIME TO THE SOUTH AND A VERY
FAVORABLE CONVECTIVE REGIME NORTH AND WEST OF THE SUWANNEE RIVER
VALLEY. WITH THIS IN MIND WILL ONCE AGAIN HIGHLIGHT NOCTURNAL
SHOWERS/STORMS DEVELOPING OVER THE NORTHERN COASTAL WATERS...THEN
MIGRATING BACK TOWARD THE COAST DURING THE LATE NIGHT HOURS. BEST
CHANCES TO SEE THIS LATE NIGHT CONVECTION WILL BE ALONG COASTAL
LEVY/CITRUS COUNTIES.
THURSDAY...UPPER RIDGE AXIS AND ENHANCED SUPPRESSION WILL CONTINUE
OVER THE SOUTHERN HALF OF THE AREA. WILL KEEP THE HIGHEST RAIN
CHANCES (35-50%) ALONG AND NORTH OF THE I-4 CORRIDOR...AND THE
HIGHEST TEMPERATURES (MIDDLE 90S) FURTHER SOUTH. FROM THE TAMPA BAY
AREA AND SOUTHWARD...GOOD CHANCE TO SEE THE SEA-BREEZE CLEAR OUT ANY
WIDELY SCT SHOWERS FROM THE BEACHES BY MID-AFTERNOON.
FRIDAY...LOOKS TO BE THE LEAST ACTIVE DAY OF THE WORK WEEK IN TERMS
OF CONVECTION. WILL HIGHLIGHT A 30% CHANCE FOR WIDELY SCT STORMS
OVER THE FAR NORTHERN ZONES TOWARD THE SUWANNEE RIVER VALLEY...WITH
ONLY ISOLATED 20% SHOWERS FOR THE MAJORITY OF THE AREA. WITH BOTH
THE UPPER AND SURFACE RIDGE AXIS LIFTING NORTH OF THE FORT MYERS
AREA...WOULD NOT BE SURPRISED TO SEE A BIT BETTER CHANCE FOR LATE
DAY STORMS DOWN TOWARD CHARLOTTE/LEE COUNTIES...BUT WILL ONLY
HIGHLIGHT A 30% CHANCE FOR NOW. THE BIGGER STORY FOR FRIDAY WILL BE
THE TEMPERATURES. MANY LOCATIONS AWAY FROM THE BEACHES WILL SEE THE
MERCURY SOAR INTO THE MIDDLE 90S...WITH NORMALLY HOTTER LOCATIONS OF
HARDEE/DE SOTO/HIGHLANDS COUNTIES REACHING THE UPPER 90S.
&&
.LONG TERM (SATURDAY THROUGH NEXT WEDNESDAY)...
OVERALL THE GLOBAL MODELS HAVE NOT CHANGED MUCH. A STRONG
SUB-TROPICAL RIDGE WILL STRETCH WESTWARD FROM THE ATLANTIC TO
CENTRAL FLORIDA THROUGH THE PERIOD. THE DRIER AIR WILL BE RETREATING
NORTHWARD FRIDAY NIGHT WITH HIGHER PRECIPITABLE WATERS RETURNING
FROM SOUTH TO NORTH ON SATURDAY. ONCE AGAIN MEX POPS ARE QUITE
LOW...SO WILL CONTINUE TO JUST SHOW A SLIGHT CHANCE OF AFTERNOON
STORMS ON SATURDAY.
ON SUNDAY...PRECIPITABLE WATERS RISE TO WELL OVER 2 INCHES FOLLOWING
A THE PASSAGE OF A WEAK TROPICAL WAVE. THIS SHOULD ALLOW RAIN
CHANCES TO RETURN TO NORMAL WITH 40 TO 50 PERCENT CHANCES DURING THE
AFTERNOON HOURS.
DRY AIR BEGINS TO MOVE BACK IN FROM THE SOUTH ON MONDAY WITH RAIN
CHANCES DECREASING TO ONLY 20 TO 30 PERCENT AGAIN BY TUESDAY.
IT WILL BE QUITE HOT ON SATURDAY WITH WIDESPREAD MID 90S LIKELY AWAY
FROM THE COAST. ADDITIONAL CLOUD COVER AND SHOWER ACTIVITY WILL KEEP
IT A COUPLE OF DEGREES COOLER ON SUNDAY...THEN THE MID 90S RETURN
AGAIN WITH THE DRIER AIR IN PLACE BY TUESDAY.
&&
.AVIATION...
MAINLY VFR CONDITIONS EXPECTED THROUGH MID-MORNING WEDNESDAY WITH
SOME MVFR OR IFR CONDITIONS POSSIBLE 15Z TO 00Z AS SHOWERS AND
THUNDERSTORMS REDEVELOP WITH HEATING. COVERAGE AND TIMING OF SHOWERS
STILL NOT CERTAIN SO WILL HANDLE WITH VCTS AT THIS TIME.
&&
.MARINE...
THE SUBTROPICAL RIDGE AXIS WILL REMAIN ALIGNED OVER THE SOUTHERN AND
CENTRAL WATERS THROUGH THE NEXT SEVERAL DAYS. THIS POSITION WILL
KEEP WINDS AND SEAS BELOW HEADLINE CRITERIA INTO THE UPCOMING
WEEKEND. THE BEST CHANCES FOR SCATTERED SHOWERS AND STORMS OVER THE
COASTAL WATERS WILL BE FROM TAMPA BAY NORTHWARD ALONG THE NATURE
COAST.
&&
.FIRE WEATHER...
NO SIGNIFICANT FIRE WEATHER CONCERNS ANTICIPATED THROUGH FRIDAY.
ALTHOUGH TEMPERATURES WILL BE INCREASING EACH AFTERNOON FOR THE NEXT
SEVERAL DAYS...RELATIVE HUMIDITY LEVELS ARE STILL FORECAST TO
GENERALLY REMAIN ABOVE CRITICAL VALUES.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 88 77 92 78 / 50 20 20 10
FMY 91 76 93 76 / 30 20 20 10
GIF 91 76 95 75 / 50 30 40 20
SRQ 89 76 91 76 / 50 20 20 10
BKV 90 72 93 73 / 60 20 30 10
SPG 88 78 91 80 / 50 20 20 10
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
SYNOPSIS/SHORT TERM/MARINE/FIRE WX...MROCZKA
AVIATION/LONG TERM...JILLSON
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
612 PM EDT WED JUL 18 2012
.SYNOPSIS...
ATLANTIC HIGH PRESSURE WILL EXTEND ACROSS THE REGION THROUGH THE
WEEK...WHILE A WEAK TROUGH OF LOW PRESSURE LINGERS INLAND THROUGH
FRIDAY. A COLD FRONT WILL APPROACH FROM THE NORTH SATURDAY...YET
DISSIPATE SUNDAY AS THE ATLANTIC HIGH BUILDS BACK INTO THE AREA.
A LEE SIDE TROUGH WILL DEVELOP AGAIN FOR NEXT TUESDAY AND
WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
RECENTLY UPDATED OUR GRIDDED AND TEXT PRODUCTS TO KEEP UP WITH TRENDS
IN TEMPERATURES AND CONVECTIVE TRENDS. OVERALL IT/S LOOKING LIKE
POTENTIAL FOR SCATTERED SHOWERS AND TSTMS IS WANING. OUR WESTERN ZONES
HAVE LITTLE IN THE WAY OF CUMULUS TOWERS PER LATEST VISIBLE DESPITE
GOOD LATE DAY INSOLATION. THE BULK OF THE CONVECTION IS FIRING ON THE
N SIDE OF THE UPPER LOW IN THE LEE SIDE SURFACE TROUGH TO THE NW OF
THE FORECAST AREA.
THE OTHER REGION OF TSTMS WERE DOWN TO THE S OF THE ALTAMAHA RIVER
AND THE RUC RAPID REFRESH WHICH DEPICTS THIS ACTIVITY...GENERALLY
WEAKENS IT IN THE NEXT 1-2 HOURS. OVERALL WE HAVE DIMINISHED POPS TO
15-20 PERCENT IN MANY AREAS. WE MAINTAINED CHANCE POPS TO THE S OF
I-16 IN GEORGIA.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/...
THE PERSISTENT TUTT FEATURE WILL GRADUALLY DISSIPATE ON
THURSDAY...LEAVING A BROAD UPPER TROUGH ALONG THE EAST COAST AND AN
ATLANTIC RIDGE OTHERWISE IN CONTROL OF THE PATTERN ALOFT. THE
SURFACE PATTERN WILL BE DEFINED BY AN INLAND TROUGH LINGERING ACROSS
THE CENTRAL CAROLINAS THROUGH FRIDAY...WHILE ATLANTIC HIGH PRESSURE
STRETCHES TOWARD THE COASTLINE INTO THE WEEKEND.
DECENT DEEP LAYER MOISTURE WILL REMAIN OVER THE MID ATLANTIC AND
SOUTHEAST STATES...AS SEEN IN PWAT VALUES NEAR OR SLIGHTLY ABOVE 2
INCHES. WHEN COMBINED WITH WARM TEMPERATURES PEAKING IN THE LOW TO
MID 90S AND MODERATE INSTABILITY...EXPECT SCATTERED SHOWERS AND
THUNDERSTORMS TO DEVELOP BY EARLY AFTERNOON EACH DAY. THERE WILL
BE NUMEROUS BOUNDARIES FOR INITIATING AND ENHANCING
CONVECTION...INCLUDING THE SEA BREEZE...LAKE BREEZES FROM LAKE
MOULTRIE/MARION...DIFFERENTIAL HEATING BOUNDARIES...AS WELL AS
OUTFLOWS THAT DEVELOP ONCE CONVECTION GETS UNDERWAY. A COLD FRONT
WILL BE DESCENDING AND LIKELY STALLING TO THE NORTH BY
SATURDAY...AND CONVECTIVE COVERAGE WILL LIKELY INCREASE ACROSS
NORTHERN AREAS AS A RESULT. EXPECT MAINLY PULSE TYPE STORMS THURSDAY
AND FRIDAY...EXCEPT WHERE BOUNDARY COLLISIONS OCCUR AND POTENTIALLY
INITIATE MULTICELL CLUSTERS. ISOLATED THUNDERSTORMS COULD BECOME
SEVERE...WITH THE MAIN THREATS BEING HEAVY RAINFALL AND WET
DOWNBURSTS PRODUCING LOCALLY DAMAGING WINDS. DEPENDING ON THE
PROXIMITY OF THE FRONT ON SATURDAY...CONVECTION COULD BECOME MORE
ORGANIZED. WILL CONTINUE TO INDICATE PRECIPITATION CHANCES IN THE 30
TO 40 PERCENT RANGE THURSDAY...INCREASING INTO THE 40 PERCENT RANGE
TO NEAR 50 PERCENT FRIDAY AND SATURDAY.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
THE COLD FRONT TO THE NORTH WILL DISSIPATE SUNDAY...AS ATLANTIC
RIDGING BOTH AT THE SURFACE AND ALOFT BUILDS ACROSS THE AREA INTO
MONDAY. HOWEVER...THE RIDGE ALOFT RETROGRADES WESTWARD FROM THE
ATLANTIC INTO THE NORTHERN GULF BY TUESDAY AND WEDNESDAY...WHILE
AT THE SAME TIME A SURFACE TROUGH AGAIN SETS UP TO THE LEE OF THE
APPALACHIANS. WHILE HEIGHTS ALOFT ARE HIGHER DURING THIS TIME...
THERE IS STILL A WEST AND NORTHWEST FLOW ALOFT TO ALLOW FOR
UPSTREAM CONVECTION TO FORM AND INTERACT WITH LOW LEVEL MESOSCALE
BOUNDARIES. THUS...FEEL OBLIGATED TO HOLD ON TO SLIGHT CHANCE OR
EVEN CHANCE POPS THROUGHOUT THE ENTIRE LONG TERM PERIOD.
CONVECTION WILL BE DIURNALLY DRIVEN...WITH ISOLATED PULSE SEVERE
WEATHER NOT OUT OF THE QUESTION WITHIN THE AFOREMENTIONED WEST AND
NORTHWEST FLOW ALOFT. TEMPERATURES WILL BE NEAR NORMAL VALUES.
&&
.AVIATION /22Z WEDNESDAY THROUGH MONDAY/...
IT APPEARS RISK OF SHOWERS/TSTMS DIMINISHING AT THE TERMINALS WITH
STORMS NOW DISSIPATED. MAINLY VFR UNTIL POSSIBLY ANOTHER ROUND OF
DIURNAL CONVECTION ON THU AFTERNOON.
EXTENDED AVIATION OUTLOOK...THE RISK FOR DIURNAL SHRA/TSRA WILL BE
ENHANCED THURSDAY AND FRIDAY DUE TO AN INLAND TROUGH OF LOW
PRESSURE...AND AGAIN ON SATURDAY IN ADVANCE OF AN APPROACHING COLD
FRONT. PERIODIC MVFR OR LOWER CONDITIONS WILL OCCUR AS A RESULT OF
THE CONVECTION.
&&
.MARINE...
AN ENHANCED GRADIENT BETWEEN AN INLAND TROUGH AND ATLANTIC HIGH
PRESSURE WILL SUPPORT SLIGHTLY HIGHER WINDS AND SEAS ACROSS THE
MARINE ZONES. A TYPICAL SOUTHWEST FLOW WILL PREVAIL THROUGH THE
ENTIRE PERIOD...WITH VEERING AT NIGHT UNDER LAND BREEZE
CIRCULATIONS...AND BACKING DURING THE DAYTIME HOURS WITH THE SEA
BREEZE. THERE WILL BE PERIODIC SURGES...EITHER FROM THE SEA BREEZE
DEVELOPMENT AND/OR FROM NOCTURNAL LOW LEVEL JETTING. AS A
RESULT...WINDS WILL BE AS HIGH AS HIGH AS 15 KT...EVEN
OCCASIONALLY CLOSE TO 20 KT. SEAS WILL GENERALLY HOLD IN THE 2 TO
4 FT RANGE. A WEAK COLD FRONT WILL APPROACH FROM THE NORTH BY THE
WEEKEND...AND WITH WEAK LOW PRESSURE DEVELOPING ALONGSIDE...EXPECT
A WEAKENING PRESSURE GRADIENT TO RESULT.
RIP CURRENTS...A PERSISTENT 2 FT 10 SEC SWELL IS EVIDENT FROM
LOCAL BUOY REPORTS...AND CONSIDERING THE NEW MOON ON THURSDAY...
HAVE EXTENDED A MODERATE RISK FOR RIP CURRENTS FOR ALL AREA
BEACHES THURSDAY.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...79
LONG TERM...RJB
AVIATION...BDC/79
MARINE...JRL/RJB/79
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
153 PM EDT WED JUL 18 2012
.PREV DISCUSSION...
UPDATE...
/ISSUED 1046 AM EDT WED JUL 18 2012/
NOT MUCH IN THE WAY OF CHANGES TO THE FORECAST THIS MORNING.
CLOUD COVERAGE HAS SLOWED HOURLY TEMPS SO DID MAKE ADJUSTMENTS TO
HOURLY TRENDS. THERE ARE SOME BREAKS IN THE CLOUDS ACROSS THE CWA
SO DID NOT ADJUST MAX TEMPS FOR NOW. AS PREVIOUSLY NOTED
THOUGH....RAIN TODAY WILL HAVE AN IMPACT ON WHETHER ALL SITES
REACH THEIR FORECAST MAX TEMPS...TO LOCALIZED THOUGH FOR
ADJUSTMENTS AT THIS TIME.
HAVE ALREADY SEEN ACTIVITY ALL MORNING...BUT STILL EXPECTING MORE
COVERAGE BY THIS AFTERNOON...UNCERTAINTY THOUGH IN BEING ABLE TO
NARROW DOWN TIMING ANY FURTHER. WRF NMM AND HRRR /ALTHOUGH THE
HRRR RUN ISNT FOR THE MOST RECENT TIME PERIOD/ SUGGEST BEST
CHANCES OF RAIN THROUGH ABOUT MID AFTERNOON WHEREAS THE LOCAL WRF
MODEL SUGGESTS THE BEST CHANCE OF POPS DURING THE LATE AFTERNOON
INTO THE EVENING.
11
SHORT TERM /TODAY THROUGH THURSDAY NIGHT/...
/ISSUED AT 350 AM EDT WED JUL 18 2012/
MODELS ARE MAINTAINING GOOD AGREEMENT THROUGH 48 HOURS. THE H5 LOW
OVER THE GA/FL BORDER WILL DRIFT INTO SOUTH/CENTRAL GEORGIA TODAY
AND THEN STALL AND DISSIPATE...OPENING UP INTO A WEAK TROUGH THAT
WILL REMAIN OVER THE CWA ON THURSDAY. THIS WILL CONTINUE TO BRING
ATLANTIC MOISTURE INTO THE CWA THROUGH THE SHORT TERM. WEAK UPPER
IMPULSES WILL CONTINUE ACROSS THE REGION THROUGH THE SHORT TERM AS
WELL...AND GIVEN THE AMOUNT OF COVERAGE OF CONVECTION OVER THE PAST
2 DAYS...SEE NO REASON WHY THERE WOULD BE LESS TODAY...THEREFORE
WILL INCREASE POPS TO LIKELY THIS AFTERNOON. MODELS ARE GIVING 50/60
POPS ON THURSDAY AND AGAIN SEE NO REASON TO GO LESS. AS FOR THE
NIGHTTIME PERIODS...AS WITH EARLY THIS MORNING...CONVECTION REMAINS
A POSSIBILITY. POCKETS OF WARM AIR COUPLED WITH THE UPPER
IMPULSES...WILL BE ENOUGH TO AID IN ISOLATED CONVECTION PAST
MIDNIGHT SO WILL CONTINUE WITH 20 POPS AFTER MIDNIGHT TONIGHT AND
THURSDAY NIGHT.
TEMPS ARE TRICKY AS AREAS THAT RECEIVE RAIN EARLY MAY STRUGGLE TO
GET OUT OF THE UPPER 80S...HOWEVER A DELAY IN RAIN OR NO RAIN AT ALL
COULD PUSH TEMPS INTO THE LOW AND MID 90S. WILL THEREFORE NOT STRAY
TOO FAR FROM GUIDANCE...WHICH IS VERY CLOSE TO PERSISTENCE...AND GO
WITH MAX TEMPS IN THE LOW TO MID 90S BOTH TODAY AND THURSDAY.
NIGHTTIME LOWS WILL REMAIN QUITE WARM AND MUGGY.
17
LONG TERM /FRIDAY THROUGH TUESDAY/...
/ISSUED AT 350 AM EDT WED JUL 18 2012/
EXTENDED PERIOD MODEL AGREEMENT DECENT WITH REMAINS OF UPPER LEVEL
LOW PRESSURE SYSTEM AND ASSOCIATED SURFACE TROUGH POSITIONED
ACROSS NORTH AND CENTRAL GEORGIA ON FRIDAY AS SURFACE LOW DEVELOPS
OVER THE CAROLINAS. THIS LOW WILL CONTINUALLY ADD MOISTURE TO AN
ALREADY MOIST ENVIRONMENT...AND EXPECTING GOOD PRECIP
COVERAGE...ESPECIALLY ACROSS NORTH GEORGIA. AS A RESULT...HAVE
GONE WITH LIKELY POPS NORTH...DIMINISHING TO GOOD CHANCE POPS
FURTHER SOUTH. BY SATURDAY...FRONTAL BOUNDARY SAGGING OUT OF THE
TENNESSEE VALLEY IS EXPECTED TO PUSH INTO NORTH AND CENTRAL
GEORGIA...KEEPING AMPLE MOISTURE ALIGNED ALONG THE FRONT. HAVE
GONE WITH LIKELY POPS ACROSS THE MIDDLE CWA...HIGHLIGHTING FRONT
PROGRESSION. THIS AREA OF LIKELY POPS IS SUBJECT TO CHANGE AS
SATURDAY APPROACHES DUE TO MODEL UNCERTAINTY WITH TIMING AND
LOCATION OF THE BOUNDARY. FOR FRIDAY AND SATURDAY...ENHANCED
CONVECTION IS EXPECTED TO BE COUPLED WITH DIURNAL HEATING...SO
HAVE DIMINISHED POPS SOMEWHAT INTO THE OVERNIGHT HOURS.
BY EARLY NEXT WEEK...HIGH PRESSURE OVER THE WESTERN ATLANTIC
ATTEMPTS TO NOSE BACK INTO THE REGION...WITH THE FLOW AROUND THE
RIDGE PULLING GULF MOISTURE INTO THE STATE. MEANWHILE...MODELS
SHOWING ANOTHER SHORTWAVE PUSHING INTO THE REGION WITH LEE SIDE
SURFACE TROUGH SETTING UP ALONG THE APPALACHIANS ASSOCIATED WITH
LOW PRESSURE OVER THE CANADIAN MARITIMES. AS A RESULT OF THESE
FEATURES...HAVE GENERALLY GONE WITH CHANCE POPS THROUGH THE
REMAINDER OF THE EXTENDED FORECAST PERIOD.
AS FOR TEMPERATURES...MODELS CONSISTENT WITH SHOWING COOLER 850MB
TEMPERATURES...SOMEWHERE IN THE 16.5 TO 17.5 RANGE...INTO THE
WEEKEND...AND WITH INCREASED PRECIP ACTIVITY AND PLENTY OF CLOUD
COVER...HAVE TENDED TOWARDS SLIGHTLY COOLER AFTERNOON HIGH
TEMPERATURES CLOSER TO SEASONAL NORMS. BY NEXT WEEK...WITH FLOW
OFF THE NORTHERN GULF ANTICIPATED BY MONDAY...850MB TEMPS WARM
2-2.5C...AND HAVE GONE WITH LOW 90 HIGHS MONDAY THROUGH WEDNESDAY.
WITH THE MOIST ENVIRONMENT PERSISTING THROUGH THE
WEEK...HEAVY RAIN STILL REMAINS A THREAT IN CONVECTION. FORECAST
SOUNDINGS SHOWING NEAR 2.0 INCH PWS INTO THE WEEKEND. QPF FOR
FRIDAY THROUGH SUNDAY MORNING IS EXPECTED TO BE WIDESPREAD 1-1.5
INCHES...WITH LOCALLY HEAVIER AMOUNTS.
31
AVIATION...
12Z UPDATE...
/ISSUED 729 AM EDT WED JUL 18 2012/
NEW CONVECTION ALONG THE AL/GA BORDER WEST OF ATL PROBABLY IN
RESPONSE TO OUTFLOW AND THE UPPER LOW. THIS COULD BE THE START OF
ANOTHER ACTIVE DAY AND WILL MAINTAIN PREDOMINANT TSRA OVER THE
FORECAST AREA BY 18Z WITH VCSH BEGINNING AROUND 14Z. CONVECTION
SHOULD DISSIPATE WITH THE LOSS OF DAYTIME HEATING TONIGHT. WINDS
WILL REMAIN ON THE WEST SIDE LESS THAN 10 KTS...BECOMING CALM
TONIGHT.
//ATL CONFIDENCE...12Z UPDATE...
MEDIUM ON TIMING OF CONVECTION.
HIGH ON ALL OTHER ELEMENTS.
17
&&
.AVIATION...
18Z UPDATE...
CONVECTION ALREADY STARTED ACROSS NORTH GEORGIA AND EXPECT IT TO
IMPACT TAF SITES THIS AFTERNOON. TIMING IS UNCERTAIN THOUGH AND IS
THE NEAR TERM CHALLENGE. THINK BEST CHANCES ARE IN THE 20-23Z
RANGE ACROSS THE NORTHERN TAF SITES AND 22-02Z ACROSS THE SOUTHERN
TAF SITES. EVEN THOUGH THERE HAS BEEN SOME VARIABILITY IN THE
WINDS...THEY SHOULD REMAIN ON THE WEST SIDE...EXCEPT FOR IMPACTS
FROM OUTFLOW BOUNDARIES. SOME SITES SAW LOW STRATUS THIS MORNING
AND SOME CONCERN FOR THIS AGAIN TOMORROW MORNING...CONFIDENCE TOO
LOW TO MENTION IN THE TAF THOUGH AT THIS POINT.
//ATL CONFIDENCE...18Z UPDATE...
HIGH ON WIND...EXCEPT NEAR TSRA. MEDIUM CONFIDENCE ON VSBYS AND
CIGS. LOW CONFIDENCE ON TIMING OF TSRA THIS AFTERNOON.
11
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 93 71 93 73 / 60 40 60 30
ATLANTA 92 72 92 73 / 60 40 60 30
BLAIRSVILLE 85 67 85 69 / 60 40 60 30
CARTERSVILLE 92 70 92 71 / 60 40 60 30
COLUMBUS 94 73 93 73 / 60 40 60 30
GAINESVILLE 91 71 91 72 / 60 40 60 30
MACON 94 72 94 73 / 60 40 60 30
ROME 93 71 93 73 / 60 40 60 30
PEACHTREE CITY 92 71 92 71 / 60 40 60 30
VIDALIA 92 74 92 75 / 60 40 60 20
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...11
SHORT TERM...17
LONG TERM....31
AVIATION...11
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
1046 AM EDT WED JUL 18 2012
.UPDATE...
NOT MUCH IN THE WAY OF CHANGES TO THE FORECAST THIS MORNING.
CLOUD COVERAGE HAS SLOWED HOURLY TEMPS SO DID MAKE ADJUSTMENTS TO
HOURLY TRENDS. THERE ARE SOME BREAKS IN THE CLOUDS ACROSS THE CWA
SO DID NOT ADJUST MAX TEMPS FOR NOW. AS PREVIOUSLY NOTED
THOUGH....RAIN TODAY WILL HAVE AN IMPACT ON WHETHER ALL SITES
REACH THEIR FORECAST MAX TEMPS...TO LOCALIZED THOUGH FOR
ADJUSTMENTS AT THIS TIME.
HAVE ALREADY SEEN ACTIVITY ALL MORNING...BUT STILL EXPECTING MORE
COVERAGE BY THIS AFTERNOON...UNCERTAINTY THOUGH IN BEING ABLE TO
NARROW DOWN TIMING ANY FURTHER. WRF NMM AND HRRR /ALTHOUGH THE
HRRR RUN ISNT FOR THE MOST RECENT TIME PERIOD/ SUGGEST BEST
CHANCES OF RAIN THROUGH ABOUT MID AFTERNOON WHEREAS THE LOCAL WRF
MODEL SUGGESTS THE BEST CHANCE OF POPS DURING THE LATE AFTERNOON
INTO THE EVENING.
11
&&
.PREV DISCUSSION...
SHORT TERM /TODAY THROUGH THURSDAY NIGHT/...
/ISSUED AT 350 AM EDT WED JUL 18 2012/
MODELS ARE MAINTAINING GOOD AGREEMENT THROUGH 48 HOURS. THE H5 LOW
OVER THE GA/FL BORDER WILL DRIFT INTO SOUTH/CENTRAL GEORGIA TODAY
AND THEN STALL AND DISSIPATE...OPENING UP INTO A WEAK TROUGH THAT
WILL REMAIN OVER THE CWA ON THURSDAY. THIS WILL CONTINUE TO BRING
ATLANTIC MOISTURE INTO THE CWA THROUGH THE SHORT TERM. WEAK UPPER
IMPULSES WILL CONTINUE ACROSS THE REGION THROUGH THE SHORT TERM AS
WELL...AND GIVEN THE AMOUNT OF COVERAGE OF CONVECTION OVER THE PAST
2 DAYS...SEE NO REASON WHY THERE WOULD BE LESS TODAY...THEREFORE
WILL INCREASE POPS TO LIKELY THIS AFTERNOON. MODELS ARE GIVING 50/60
POPS ON THURSDAY AND AGAIN SEE NO REASON TO GO LESS. AS FOR THE
NIGHTTIME PERIODS...AS WITH EARLY THIS MORNING...CONVECTION REMAINS
A POSSIBILITY. POCKETS OF WARM AIR COUPLED WITH THE UPPER
IMPULSES...WILL BE ENOUGH TO AID IN ISOLATED CONVECTION PAST
MIDNIGHT SO WILL CONTINUE WITH 20 POPS AFTER MIDNIGHT TONIGHT AND
THURSDAY NIGHT.
TEMPS ARE TRICKY AS AREAS THAT RECEIVE RAIN EARLY MAY STRUGGLE TO
GET OUT OF THE UPPER 80S...HOWEVER A DELAY IN RAIN OR NO RAIN AT ALL
COULD PUSH TEMPS INTO THE LOW AND MID 90S. WILL THEREFORE NOT STRAY
TOO FAR FROM GUIDANCE...WHICH IS VERY CLOSE TO PERSISTENCE...AND GO
WITH MAX TEMPS IN THE LOW TO MID 90S BOTH TODAY AND THURSDAY.
NIGHTTIME LOWS WILL REMAIN QUITE WARM AND MUGGY.
17
LONG TERM /FRIDAY THROUGH TUESDAY/...
/ISSUED AT 350 AM EDT WED JUL 18 2012/
EXTENDED PERIOD MODEL AGREEMENT DECENT WITH REMAINS OF UPPER LEVEL
LOW PRESSURE SYSTEM AND ASSOCIATED SURFACE TROUGH POSITIONED
ACROSS NORTH AND CENTRAL GEORGIA ON FRIDAY AS SURFACE LOW DEVELOPS
OVER THE CAROLINAS. THIS LOW WILL CONTINUALLY ADD MOISTURE TO AN
ALREADY MOIST ENVIRONMENT...AND EXPECTING GOOD PRECIP
COVERAGE...ESPECIALLY ACROSS NORTH GEORGIA. AS A RESULT...HAVE
GONE WITH LIKELY POPS NORTH...DIMINISHING TO GOOD CHANCE POPS
FURTHER SOUTH. BY SATURDAY...FRONTAL BOUNDARY SAGGING OUT OF THE
TENNESSEE VALLEY IS EXPECTED TO PUSH INTO NORTH AND CENTRAL
GEORGIA...KEEPING AMPLE MOISTURE ALIGNED ALONG THE FRONT. HAVE
GONE WITH LIKELY POPS ACROSS THE MIDDLE CWA...HIGHLIGHTING FRONT
PROGRESSION. THIS AREA OF LIKELY POPS IS SUBJECT TO CHANGE AS
SATURDAY APPROACHES DUE TO MODEL UNCERTAINTY WITH TIMING AND
LOCATION OF THE BOUNDARY. FOR FRIDAY AND SATURDAY...ENHANCED
CONVECTION IS EXPECTED TO BE COUPLED WITH DIURNAL HEATING...SO
HAVE DIMINISHED POPS SOMEWHAT INTO THE OVERNIGHT HOURS.
BY EARLY NEXT WEEK...HIGH PRESSURE OVER THE WESTERN ATLANTIC
ATTEMPTS TO NOSE BACK INTO THE REGION...WITH THE FLOW AROUND THE
RIDGE PULLING GULF MOISTURE INTO THE STATE. MEANWHILE...MODELS
SHOWING ANOTHER SHORTWAVE PUSHING INTO THE REGION WITH LEE SIDE
SURFACE TROUGH SETTING UP ALONG THE APPALACHIANS ASSOCIATED WITH
LOW PRESSURE OVER THE CANADIAN MARITIMES. AS A RESULT OF THESE
FEATURES...HAVE GENERALLY GONE WITH CHANCE POPS THROUGH THE
REMAINDER OF THE EXTENDED FORECAST PERIOD.
AS FOR TEMPERATURES...MODELS CONSISTENT WITH SHOWING COOLER 850MB
TEMPERATURES...SOMEWHERE IN THE 16.5 TO 17.5 RANGE...INTO THE
WEEKEND...AND WITH INCREASED PRECIP ACTIVITY AND PLENTY OF CLOUD
COVER...HAVE TENDED TOWARDS SLIGHTLY COOLER AFTERNOON HIGH
TEMPERATURES CLOSER TO SEASONAL NORMS. BY NEXT WEEK...WITH FLOW
OFF THE NORTHERN GULF ANTICIPATED BY MONDAY...850MB TEMPS WARM
2-2.5C...AND HAVE GONE WITH LOW 90 HIGHS MONDAY THROUGH WEDNESDAY.
WITH THE MOIST ENVIRONMENT PERSISTING THROUGH THE
WEEK...HEAVY RAIN STILL REMAINS A THREAT IN CONVECTION. FORECAST
SOUNDINGS SHOWING NEAR 2.0 INCH PWS INTO THE WEEKEND. QPF FOR
FRIDAY THROUGH SUNDAY MORNING IS EXPECTED TO BE WIDESPREAD 1-1.5
INCHES...WITH LOCALLY HEAVIER AMOUNTS.
31
AVIATION...
12Z UPDATE...
/ISSUED 729 AM EDT WED JUL 18 2012/
NEW CONVECTION ALONG THE AL/GA BORDER WEST OF ATL PROBABLY IN
RESPONSE TO OUTFLOW AND THE UPPER LOW. THIS COULD BE THE START OF
ANOTHER ACTIVE DAY AND WILL MAINTAIN PREDOMINANT TSRA OVER THE
FORECAST AREA BY 18Z WITH VCSH BEGINNING AROUND 14Z. CONVECTION
SHOULD DISSIPATE WITH THE LOSS OF DAYTIME HEATING TONIGHT. WINDS
WILL REMAIN ON THE WEST SIDE LESS THAN 10 KTS...BECOMING CALM
TONIGHT.
//ATL CONFIDENCE...12Z UPDATE...
MEDIUM ON TIMING OF CONVECTION.
HIGH ON ALL OTHER ELEMENTS.
17
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 93 71 93 73 / 60 40 60 30
ATLANTA 92 72 92 73 / 60 40 60 30
BLAIRSVILLE 85 67 85 69 / 60 40 60 30
CARTERSVILLE 92 70 92 71 / 60 40 60 30
COLUMBUS 94 73 93 73 / 60 40 60 30
GAINESVILLE 91 71 91 72 / 60 40 60 30
MACON 94 72 94 73 / 60 40 60 30
ROME 93 71 93 73 / 60 40 60 30
PEACHTREE CITY 92 71 92 71 / 60 40 60 30
VIDALIA 92 74 92 75 / 60 40 60 20
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...11
SHORT TERM...17
LONG TERM....31
AVIATION...17
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
125 AM EDT WED JUL 18 2012
.UPDATE...
/ISSUED AT 1035 PM EDT TUE JUL 17 2012/
HAVE LEFT SLIGHT CHANCE POPS ACROSS THE CWA FOR THE REMAINDER OF THE
NIGHT...EXCEPT CHANCE FOR AREAS NORTH OF ATLANTA TO ATHENS. SOME
CONVECTION DEVELOPING NEAR CHATTANOOGA AND DRIFTING SOUTH. RAIN
COOLED AIR HAS REACHED THE FORECAST MIN TEMPERATURES IN A FEW AREAS.
SO HAVE LOWERED THE OVERNIGHT MINS A BIT. OTHERWISE NO CHANGES.
41
&&
.PREVIOUS...
SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
/ISSUED AT 408 PM EDT TUE JUL 17 2012/
PRIMARY CONCERN IS COVERAGE OF TSRA THIS AFTERNOON AND EVOLUTION
THIS EVENING. SO FAR TODAY...CONVECTION CLOSELY FOLLOWING MORNING
HRRR RUNS WITH ONE COMPLEX MOVING THROUGH EAST AND NOW SOUTHERN
PARTS OF ATL METRO. OTHER SCT STORMS ACROSS WESTCENTRAL AND FAR NE
GA. HRRR DID PROG ABUNDANT CONVECTION OVER NW GA TO NRN AL ALONG
CUMBERLAND PLATEAU AFTER 21Z WHICH IS NOT PANNING OUT SO FAR.
EXPECT TSRA TO CONTINUE TO PUSH SLOWLY SSW. HEAVY RAIN HAS BEEN
OCCURRING BUT FORTUNATELY...NO ONE AREA IS APPROACHING FFG.
EXPECTION TSRA TO WEAKEN SOME AFTER 6PM AND DISSIPATE BY 9PM.
UPPER LOW OVER NRN FL CONTINUES TO BE PRIMARY FEATURE. THIS LOW
PROGGED BY ALL MODELS TO DRIFT NORTH TONIGHT AND TOMORROW AS IT
GETS PICKED UP BY WEAK WESTERLIES WHICH DRIFT INTO THE MID
ATLANTIC WED. IMPACT FOR CWA IS HIGH MEAN RH AND CONTINUED DIURNAL
CONVECTION WITH NO PREFERENCE FOR ANY ONE LOCATION. CHC POPS
APPEAR MOST APPROPRIATE. ISOLD SVR STORMS AGAIN LIKELY. IF WE GET
MORE CLOUDS OR MORNING PRECIP WED...WILL SEE LESS THAN TODAY.
HAVE TWEAKED MAX TEMP GUIDANCE UP A LITTLE BASED ON RECENT TRENDS
AND MORE ISOLATED AFTERNOON CONVECTION THAN MODELS DEPICTING.
GUIDANCE BLEND WORKING WELL WITH SLIGHT UPWARD ADJUSTMENT FOR MIN
TEMPS.
SNELSON
.LONG TERM /THURSDAY THROUGH TUESDAY/...
/ISSUED AT 408 PM EDT TUE JUL 17 2012/
MINOR DISCREPANCIES IN MODEL SOLUTIONS FOR THE LONG TERM BUT OVERALL
DECENT GENERAL CONSENSUS. GFS HAS GREATER AMOUNTS OF MOISTURE THAN
THE ECMWF FOR MUCH OF THE FORECAST PERIOD AND SLIGHT DIFFERENCES IN
LOCATION OF THE SFC FRONT PROGGED TO DIP SOUTHWARD INTO THE AREA FOR
THE WEEKEND. DUE TO UNCERTAINTY WITH LOCATION OF THIS BOUNDARY THIS
LATE IN THE FORECAST PERIOD... HAVE MAINTAINED CURRENT FORECAST.
PREVIOUS DISCUSSION FOLLOWS...
BAKER
/ISSUED AT 355 AM EDT TUE JUL 17 2012/
MODEL AGREEMENT THROUGH THE WEEKEND IS FAIRLY GOOD...WITH ATLANTIC
RIDGE REMAINING OFF THE EAST COAST AS UPPER LEVEL ENERGY REMAINS
ACROSS THE SOUTHEAST. TROUGH STRETCHES DOWN THE APPALACHIANS AND
EXTENDS INTO NORTH AND CENTRAL GEORGIA THROUGH THE LATER HALF OF
THE WEEK AS SURFACE LOW EXPECTED TO DEVELOP OVER THE CAROLINAS
INTO THE WEEKEND. IN ADDITION...A FRONTAL BOUNDARY PUSHES INTO THE
TENNESSEE VALLEY BY THE END OF THE WORK WEEK...AND INTO NORTH
GEORGIA BY SUNDAY MORNING. THE COMBINATION OF THESE FEATURES WILL
KEEP AMPLE MOISTURE AND ENOUGH INSTABILITY TO SUPPORT GOOD CHANCE
POPS ACROSS THE MAJORITY OF THE AREA THROUGH SUNDAY. BY NEXT
WEEK...MODEL SOLUTIONS DIFFER...THOUGH NOT AS SIGNIFICANTLY AS IN
DAYS PAST. EXTENDED MODELS AGREE WITH YET ANOTHER FRONTAL BOUNDARY
PUSHING INTO THE REGION BY TUESDAY AFTERNOON...BUT EXPECTED
IMPACTS DIFFER. ECMWF 1-2C COOLER WITH 850MB TEMPERATURES THAN THE
GFS AS THIS EARLY WEEK EVENT UNFOLDS. AS A RESULT...COULD SEE
SLIGHTLY COOLER HIGHS AS EARLY AS SUNDAY...WITH MORE SEASONAL
AFTERNOON TEMPS IN THE UPPER 80S. GRADUAL WARMING TREND EXPECTED
INTO TUESDAY WITH HIGHS BACK IN THE LOW 90S.
PRECIP ACTIVITY THROUGH THE EXTENDED WILL INCREASE EACH
AFTERNOON...COUPLED LARGELY WITH THE DIURNAL HEATING.
MOIST ENVIRONMENT WILL PERSIST THROUGH THE WEEK AND INTO THE
WEEKEND...WITH MODEL SOUNDINGS INDICATING PRECIPITABLE WATER
VALUES NEARING 2.0 INCHES.
31
&&
.AVIATION...
06Z UPDATE...
CONVECTION OVER NORTHWEST GA SHOULD REMAIN NORTHWEST OF THE ATL AREA
TAFS AND WILL NOT POSE A THREAT. PRETTY MUCH A PERSISTENCE FORECAST
WITH VFR CONDITIONS EXCEPT IN AFTERNOON THUNDERSTORMS THAT COULD
LINGER INTO THE EVENING. EXPECT ABOUT THE SAME AMOUNT OF COVERAGE AS
YESTERDAY AND WILL THEREFORE GO WITH PREDOMINANT TSRA FROM 18Z TO
22Z. THERE COULD BE SOME MORNING STRATUS AND WILL MAINTAIN THE
MENTION OF 5SM SCT015 EARLY THIS MORNING.
//ATL CONFIDENCE...06Z UPDATE...
MEDIUM ON FORMATION OF MORNING STRATUS AND OF TIMING OF CONVECTION.
HIGH ON ALL OTHER ELEMENTS.
17
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 71 95 71 94 / 20 40 30 40
ATLANTA 74 92 73 91 / 20 50 30 40
BLAIRSVILLE 67 88 68 87 / 20 40 30 50
CARTERSVILLE 69 93 70 92 / 20 50 30 50
COLUMBUS 75 94 73 92 / 30 50 40 50
GAINESVILLE 72 93 72 91 / 20 40 30 50
MACON 73 94 72 93 / 30 50 30 40
ROME 70 94 71 92 / 20 50 30 50
PEACHTREE CITY 70 93 70 91 / 20 50 40 40
VIDALIA 74 94 74 95 / 30 50 40 40
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...SNELSON
LONG TERM....BAKER
AVIATION...41
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
301 PM CDT WED JUL 18 2012
.MESOSCALE DISCUSSION...
300 PM CDT
CONTINUE TO SEE PULSE TYPE STORMS FLARING UP THIS AFTERNOON IN THE
AXIS OF GREATEST INSTABILITY WHICH EXTENDS FROM NORTH CENTRAL
INDIANA WNW ACROSS MOST OF OUR CWA TO NORTHEASTERN IOWA. DEEP LAYER
SHEAR REMAINS ANEMIC WITH UNIDIRECTIONAL WESTERLY FLOW AROUND
15-20KT WHICH SHOULD CONTINUE TO RESULT IN MINIMAL STORM
ORGANIZATION...HOWEVER GIVEN THE MODERATELY STRONG INSTABILITY AND
FAIRLY LARGE DOWNDRAFT CAPE VALUES POTENTIAL EXISTS FOR WET
MICROBURSTS THROUGH EARLY EVENING WITH THE MOST INTENSE ONES
POTENTIALLY PRODUCING GENERALLY MARGINALLY SEVERE WIND IN ISOLATED
LOCATIONS. POTENTIAL FOR SEVERE HAIL APPEARS LOW GIVEN WARM
THERMODYNAMIC PROFILES AND WEAK SHEAR. VERY HIGH PRECIPITABLE WATER
VALUES SHOULD ALLOW STORMS TO BE VERY EFFICIENT RAIN PRODUCERS.
IZZI
&&
.DISCUSSION...
558 AM CDT
LATEST RADAR/SURFACE OBS SHOW FRONTAL BOUNDARY STRETCHING FROM
NEAR DUBUQUE TO MORRIS TO NEAR VALPARAISO AT 530 AM WHICH HAD
SURGED SOUTHWARD OVER THE LAST HOUR. RADAR MOSAIC SHOWS ANOTHER
BOUNDARY FROM NEAR JANESVILLE TO CHICAGO. THIS BOUNDARY IS
COINCIDENT WITH SPOTTY CONVECTION NEAR MADISON AND A FEW SMALL
CELLS OVER SOUTHERN LAKE MICHIGAN. THE MAIN AREA OF CONVECTION
REMAINS MORE CLOSELY TIED TO THE MID LEVEL BAROCLINIC ZONE RUNNING
FROM THE TWIN CITIES INTO CENTRAL LOWER MICHIGAN. HIGH RES NEAR
TERM GUIDANCE SHOWS SOME INTERESTING SOLUTIONS IN TERMS OF
WINDS/BOUNDARY PLACEMENT INTO THE AFTERNOON. THE RAP AND THE HRRR
BOTH DEPICT THE CURRENT EXPANSE OF NORTHEAST WINDS BEHIND THE
FIRST BOUNDARY BUT THEN TURN WINDS ACROSS MUCH OF THE AREA
SOUTHWESTERLY THIS MORNING WITH A BOUNDARY SETTING UP FROM NEAR
ROCKFORD TO JOLIET TO RENSSELAER OR SO. THIS IS AN INTERESTING
PROGRESSION OF THINGS IF THIS INITIAL BOUNDARY WERE THE TRUE COLD
FRONT. LOCAL WRF SHOWS A SIMILAR THOUGH LESS PRONOUNCED TREND.
ASSUMING THIS BOUNDARY IS THE COLD FRONT IT IS POSSIBLE THAT IT
DOES MOVE BACK NORTHWARD INTO THE MIDDLE OF THE DAY IN RESPONSE TO
THE UPPER TROUGH MOVING TOWARD THE MID/UPPER MISSISSIPPI RIVER
VALLEY GIVEN THAT THE WESTERN EXTENT OF THE FRONT IS IN NORTHWEST
IOWA CLOSER TO WHERE THE UPPER TROUGH AXIS IS NOW. ANOTHER
SCENARIO IS THAT THE INITIAL BOUNDARY WAS SOME SORT OF SHALLOW
OUTFLOW WHICH MIXES OUT THIS MORNING AND THE MAIN FRONT IS THE
BOUNDARY CLOSER TO THE CHICAGO AREA DESCRIBED ABOVE. LOOKING AT
THE VAD WIND PROFILES FROM LOT AND MKX THEY SHOW SIMILAR DEPTHS OF
NORTHEAST WINDS SO IT SEEMS THAT THIS IS A LESS LIKELY SCENARIO.
WILL KEEP THE FORECAST MORE OR LESS AS-IS FOR NOW. OTHERWISE...SPOTTY
SHRA/TSRA DEVELOPMENT IS POSSIBLE BUT THE BULK OF THE NEAR TERM
ACTIVITY LOOKS TO REMAIN TO THE NORTH OVER THE NEXT FEW HOURS.
MDB
//PREV DISCUSSION...
322 AM CDT
HEAT AND THUNDER CHANCES REMAIN THE MAIN FORECAST CHALLENGES THIS
MORNING. EARLY MORNING WATER VAPOR IMAGERY SHOWS A LARGE CLOSED
UPPER LOW OVER NORTHERN QUEBEC WITH WEAK RIDGING TO ITS WEST
EXTENDING FROM THE CENTRAL PLAINS NORTHWARD INTO NORTHERN MANITOBA.
SEVERAL SHORTWAVES ARE EMBEDDED WITH THE MORE ZONAL PORTION OF THE
RIDGING OVER THE NORTHERN PLAINS AND UPPER MISSISSIPPI RIVER VALLEY.
THE MOST NOTABLE IS A VORT MAX OVER SOUTH DAKOTA WHICH IS PART OF A
TROUGH AXIS EXTENDING FROM SOUTHERN ALBERTA INTO NORTHERN NEBRASKA
WHICH IS PUSHING EASTWARD. THIS WILL LIKELY AFFECT THE LOCAL
FORECAST COMING UP TONIGHT/THURSDAY MORNING. TO THE WEST A CLOSED
UPPER LOW HAS STALLED OUT OVER THE WESTERN OREGON/CALIFORNIA BORDER.
AT THE SURFACE...AN OUTFLOW BOUNDARY FROM CONVECTION TO THE NORTH
HAD PUSHED DOWN LAKE MICHIGAN AND INTO NORTHEAST ILLINOIS THIS PAST
EVENING TURNING WINDS NORTHEASTERLY. THIS BOUNDARY HAS WASHED OUT
AS EVIDENCED BY SEVERAL SITES BEHIND WHERE IT PASSED HAVING SWITCHED
AROUND TO A SOUTHWEST WIND. THE COOL FRONT IS NOW JUST NORTH OF
FREEPORT AND JUST SOUTH OF MIDWAY AND IS STILL MOVING SOUTHWARD.
THE MOVEMENT OF THIS FRONT AND THE UPPER SHORT WAVES WILL BE THE
MAIN FEATURES OF NOTE FOR THE SHORT TERM.
TODAY...THE COOL FRONTAL POSITION WILL BE ONE OF THE MAIN CHALLENGES
THROUGH THE DAY AND WILL DICTATE THE TEMP AND PRECIP FORECASTS INTO
THIS EVENING. CURRENTLY...PRECIPITATION IS ASSOCIATED WITH THE MID
LEVEL BAROCLINIC ZONE TRAILING NORTH OF THE FRONT FROM THE TWIN
CITIES ACROSS CENTRAL LAKE MICHIGAN AND ARCHING SOUTHEASTWARD ACROSS
CENTRAL LOWER MICHIGAN. ACTIVITY WILL LIKELY FESTER ALONG THIS ZONE
PERIODICALLY THROUGH THE DAY WITH A SLOW SOUTHWARD MOVEMENT OF THE
MID LEVEL TEMP GRADIENT. AT THIS POINT EXPECT THIS TO BE FOCUSED TO
THE NORTH OF THE CWA. CANNOT COMPLETELY RULE OUT ISOLATED
DEVELOPMENT NEAR THE SURFACE FRONT THIS MORNING BUT CHANCES APPEAR
SLIM. LATEST NAM AND GFS PUT THE FRONT...IN A SOMEWHAT INCOHERENT
STATE...OVER THE FAR SOUTHWESTERN CWA BY EARLY AFTERNOON. LOCAL HIGH
RES GUIDANCE IS A LITTLE SLOWER WITH THE BOUNDARY AND THUS FURTHER
NORTH WITH IT FOR THE AFTERNOON. THE LATEST SURFACE ANALYSIS
SUGGESTS THAT THERE IS A WEAK LOW CENTER OVER NORTHEAST IOWA WHICH
THE RAP ALSO DEPICTS. THE RAP SOLUTION OF THE FRONT SLOWING AND
EVEN PUSHING BACK NORTHWARD SOMEWHAT AS THIS LOW CENTER MOVES
EASTWARD IS PLAUSIBLE. DESPITE THE UNCERTAINTY WITH THE FRONTAL
POSITION THROUGH THE DAY...THE BOUNDARY WILL MOVE INTO HIGHER
DEW POINT AIR ALLOWING FOR SOME POOLING OF MOISTURE AHEAD OF IT
THIS AFTERNOON WHICH IS EXPECTED TO RESULT IN STRONG SURFACE BASED
INSTABILITY ALONG AND SOUTH OF THE FRONT. WITH SOME MIXING
EXPECTED MIXED LAYER INSTABILITY WILL BE LOWER BUT STILL
SUFFICIENT TO SUPPORT STORMS. A SHARP INSTABILITY GRADIENT IS
EXPECTED TO SET UP WITH LATEST THINKING HAVING IT RUN FROM ROUGHLY
ROCKFORD DOWN TOWARDS JOLIET AND EASTWARD TOWARDS RENSSELAER
DURING THE AFTERNOON...WITH EXACT PLACEMENT DEPENDENT ON HOW FAR
SOUTH THE FRONT MOVES. BEYOND RATHER BROAD LOW LEVEL CONVERGENCE
ALONG THE FRONT THERE IS NOT MUCH IN THE WAY OF A LARGER SCALE
TRIGGERING MECHANISM BUT CONVECTIVE TEMPERATURES IN THE MID 90S
SHOULD BE ATTAINABLE SO ISOLATED TO SCATTERED DEVELOPMENT IS
PLAUSIBLE. STORMS THAT DO FORM WILL HAVE AT LEAST SOME SEVERE WIND
POTENTIAL GIVEN THE INVERTED V SOUNDING. EXPECT THAT THE BEST
CHANCE FOR OCCURRENCE IS FROM ROUGHLY ROCKFORD TO JOLIET TO
RENSSELAER SOUTHWARD IN LINE WITH THE EXPECTED INSTABILITY
GRADIENT. HOWEVER...THIS THREAT AREA MAY PUSH SOUTHWESTWARD IF THE
FRONT CAN KEEP SOME FORWARD SPEED THOUGH LATE AFTERNOON. TEMPS ARE
THE NEXT ISSUE...AS INDICATED ABOVE HUMIDITY WILL BE HIGHER THAN
TUESDAY AHEAD OF THE FRONT THANKS TO MOISTURE POOLING. WITH HIGHS
STILL EXPECTED TO BE IN THE MID TO EVEN UPPER 90S SOUTH WILL
MAINTAIN THE HEAT ADVISORY...BUT SOME OF THE NORTHERN PORTIONS OF
IT MAY NOT REACH CRITERIA IF THE FRONT REMAINS ON THE MOVE...OF
CONCERN WOULD BE JASPER AND NEWTON COUNTIES. WILL KEEP THE
ADVISORY GOING AS IS AND LET THE DAY SHIFT MONITOR TEMPS AND TRIM
IF NEEDED. HIGHS NORTH OF THE FRONT WILL BE TRICKIER...BUT BE
RELATIVELY COOLER WITH HIGHS IN THE UPPER 80S TO AROUND
90...THOUGH A NORTHEASTERLY WIND OFF THE LAKE WILL PROBABLY KEEP
LAKESHORE AREAS IN THE MID 80S. DO SEE SOME BUST POTENTIAL ACROSS
THESE AREAS WITH SOME CONCERN THAT FORECAST HIGHS MAY BE A BIT
WARM. IT WILL STILL BE HUMID IN THESE AREAS AS WELL BUT BELOW
ADVISORY LEVELS.
TONIGHT AND THURSDAY...LARGER SCALE FORCING INCREASES TONIGHT...MOST
NOTABLY LATE...AS THE MID LEVEL BAROCLINIC ZONE CURRENTLY NORTH OF THE
AREA RE-ORIENTS FROM WEST TO EAST TO NORTHWEST TO SOUTHEAST AND
SETTLES INTO THE AREA. IN ADDITION...THE WAVE NOTED OVER SOUTH
DAKOTA AND ITS ASSOCIATED TROUGH AXIS IS EXPECTED TO REACH THE AREA
AS IT TURNS SOUTHEASTWARD WITH THE UPPER FLOW BUCKLING AS THE LARGE
QUEBEC UPPER LOW MOVES SOUTHWARD. THE WAVE WILL CROSS THE AREA LATE
TONIGHT INTO THURSDAY MORNING AND WILL A HAVE DECENT CHANCE OF
BRINGING CONVECTION ACROSS THE ENTIRE FORECAST AREA. ITS NOT CLEAR
HOW WIDESPREAD COVERAGE WILL BE HOWEVER BUT THIS CHANCE FOR PRECIP
IS DECENT. LOW CHANCES FOR SCATTERED ACTIVITY WILL BE IN PLACE THIS
EVENING ACROSS THE SOUTHWESTERN CWA WITH LITTLE SUPPORT FOR POPS
NORTHEAST DURING THAT TIME...THOUGH THE BAROCLINIC ZONE MAY BE
GENERATING SOME ACTIVITY JUST TO THE NORTHEAST. PRECIP CHANCES WIND
DOWN THURSDAY AFTERNOON...THOUGH LOW CHANCES CONTINUE SOUTH PERHAPS
THROUGH EARLY EVENING BEFORE THE UPPER FORCING EXITS TO THE
SOUTHEAST AND SURFACE HIGH PRESSURE ARRIVES FROM THE NORTH. HIGHS
THURSDAY WILL RANGE FROM THE MID 80S NORTHEAST WITH FLOW OFF THE
LAKE TO AROUND 90 SOUTHWEST...THOUGH TEMPS MAY NOT REACH THESE
LEVELS TIL LATER IN THE AFTERNOON IF PRECIP IS IN PLACE IN THE
MORNING.
FRIDAY THROUGH TUESDAY...SURFACE HIGH PRESSURE WILL BE IN PLACE
FRIDAY WITH THE MAIN UPPER TROUGH ALONG THE EAST COAST AND A BIG
RIDGE OVER THE WESTERN AND CENTRAL U.S...WITH A RIDGE AXIS EXTENDING
NORTHEAST TOWARDS HUDSON BAY AND ANOTHER AIMED NORTHWEST INTO
ALBERTA...WITH A TROUGH PASSING BETWEEN THE TWO OVER NORTHERN
MANITOBA. THIS TROUGH FLATTENS THE EASTERN RIDGE AXIS WHILE A BIG
UPPER LOW ARRIVES OVER WESTERN BRITISH COLUMBIA TO AMPLIFY THE
WESTERN AXIS...THOUGH THERE IS A WEAK TROUGH AHEAD OF IT TO
TEMPORARILY BREAK IT DOWN. THIS RESULTS IN A NORTHWESTERLY FLOW FROM
THE NORTHERN PLAINS INTO THE LOWER GREAT LAKES BY SUNDAY. THE
QUESTION IS HOW FAR SOUTH THIS ACTIVE CORRIDOR OF FLOW WILL BE
PLACED. THE GFS KEEPS THE LOCAL AREA IN THE PATH OF WEAK SHORTWAVES
WHILE THE ECMWF...WHICH IS VERY SIMILAR IN THE OVERALL
PATTERN...KEEPS THE WAVE TRAIN A LITTLE FURTHER NORTHEAST OF HERE
INTO EARLY NEXT WEEK. FRIDAY LOOKS LIKE A RELATIVELY PLEASANT DAY
WITH SURFACE HIGH PRESSURE KEEPING A NORTHEAST WIND IN PLACE AND A
CORRIDOR OF COOLER MID LEVEL AIR...H85 TEMPS AROUND 14C...IN PLACE
BEHIND THE DEPARTING UPPER TROUGH. THIS SHOULD LEAD TO HIGHS IN THE
MID TO UPPER 80S...THOUGH SOME WESTERN AREAS COULD AGAIN TOUCH 90.
SATURDAY STILL LOOKS TO BE DRY BUT THE ABOVE BECOMES MORE OF AN
ISSUE FROM SUNDAY AND BEYOND. POP CHANCES WOULD LIKELY BE LOW
ANYWAYS GIVEN THE NATURE OF THESE EMBEDDED IMPULSES SO WILL
GENERALLY KEEP THE FORECAST DRY FOR NOW. TEMPS WILL BEGIN TO WARM
AGAIN SATURDAY AND SUNDAY...WITH SOME POTENTIAL FOR A BIGGER WARM UP
EARLY NEXT WEEK WITH THE GFS AND ECMWF PAINTING LOW 20S H85 TEMPS AT
VARIOUS TIMES. OVERALL FORECAST CONFIDENCE IN PRECIP POTENTIAL IS
LOW AND LITTLE BIT HIGHER IN TERMS OF A WARMING TREND CONTINUING
INTO EARLY NEXT WEEK.
MDB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* ISO SHRA/TSRA DEVELOPING ARND 19Z THROUGH 21-22Z.
* NE WINDS THRU SUNSET...WINDS VEERING SE/S OVERNIGHT.
* ADDTL SHRA/TSRA PSBL ARND DAYBREAK.
BEACHLER
//DISCUSSION...UPDATED 18Z...
VISIBLE IMAGERY THIS AFTN WAS DEPICTING SOME BUILDING CUMULUS
CLOUDS ACROSS NORTHERN IL/NORTHWEST IN. ADDTL DEVELOPMENT WAS
NOTED FURTHER EAST. A FRONTAL BOUNDARY WAS ORIENTED FROM RFD SE
THRU JOT. WINDS NE OF THIS BNDRY WERE FROM THE NE...WHILE WINDS SW
OF THIS WERE SOUTHERLY. GUIDANCE CONTINUES TO SHOW THIS AS THE
FOCAL POINT FOR ISO SHRA/TSRA ARND 19-20Z...THEN CONTINUE THRU
22-23Z. COVERAGE SHUD REMAIN MINIMAL. WINDS WILL THEN VEER SE THIS
EVE/OVERNIGHT...WITH A SECOND AREA OF CONVECTION PSBLY EARLY THUR
MORNING. GUIDANCE HAS CONTINUED TO FOCUS THIS SECOND AREA OF
DEVELOPMENT TOWARDS THE 11-15Z TIMEFRAME...THEN PUSH THE BULK OF
THE LOW/MID LVL MOISTURE EAST...RESULTING IN DRY WEATHER FOR THE
REMAINDER OF THE AFTN THUR. WINDS WILL THEN BACK EAST AND
EVENTUALLY NORTHEAST AS A WEAK LOW PRESSURE SLIDES EAST ACROSS
NORTHERN IL/NORTHWEST IN.
BEACHLER
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH CONFIDENCE IN WIND FORECAST.
* MEDIUM CONFIDENCE IN TS COVERAGE AND TIMING.
* MEDIUM CONFIDENCE IN ENDING OF TS/SHRA.
* LOW CONFIDENCE IN PRECIP DEVELOPMENT OVERNIGHT INTO EARLY THUR.
BEACHLER
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT...
FRI THROUGH TUE...VFR. NO SIG WX.
TRS
&&
.MARINE...
432 AM CDT
A COLD FRONT TRAILS FROM LOW PRESSURE OVER THE GULF OF ST.
LAWRENCE ACROSS SOUTHERN LOWER MI...FAR SOUTHERN LAKE MI AND FAR
NORTHERN IL EARLY THIS MORNING. THE COLD FRONT WILL CONTINUE TO
MOVE SLOWLY SOUTHWARD TODAY AND TONIGHT...EXTENDING FROM CENTRAL
IN ACROSS IL TO CENTRAL IA BY THURSDAY MORNING. HIGH PRESSURE OF
WILL BUILD SE FROM HUDSON BAY AND ONTARIO BEHIND THE COLD
FRONT...SPREADING ACROSS THE GREAT LAKES TODAY AND TONIGHT. LOW
PRESSURE WILL RIDE ALONG THE FRONTAL BOUNDARY FROM IA TO THE
UPPER OH VALLEY DURING THU WHILE A RIDGE OF HIGH PRESSURE REMAINS
OVER THE GREAT LAKES. LOW PRESSURE WILL BE TRACKING E FROM CENTRAL
CANADA TO HUDSON BAY THU NIGHT THROUGH FRI NIGHT WHILE THE RIDGE
OVER THE GREAT LAKES SHIFTS S OVER THE NORTHEASTERN U.S. AND THE
MIDWEST. THE COLD FRONT TRAILING FROM THE CANADIAN LOW WILL DROP S
ACROSS NORTHERN LAKE MI SUN NIGHT.
TRS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...HEAT ADVISORY...ILZ019-ILZ021-ILZ023-ILZ032-ILZ033-ILZ039 UNTIL
7 PM WEDNESDAY.
IN...HEAT ADVISORY...INZ010-INZ011-INZ019 UNTIL 7 PM WEDNESDAY.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1237 PM CDT WED JUL 18 2012
.DISCUSSION...
558 AM CDT
LATEST RADAR/SURFACE OBS SHOW FRONTAL BOUNDARY STRETCHING FROM
NEAR DUBUQUE TO MORRIS TO NEAR VALPARAISO AT 530 AM WHICH HAD
SURGED SOUTHWARD OVER THE LAST HOUR. RADAR MOSAIC SHOWS ANOTHER
BOUNDARY FROM NEAR JANESVILLE TO CHICAGO. THIS BOUNDARY IS
COINCIDENT WITH SPOTTY CONVECTION NEAR MADISON AND A FEW SMALL
CELLS OVER SOUTHERN LAKE MICHIGAN. THE MAIN AREA OF CONVECTION
REMAINS MORE CLOSELY TIED TO THE MID LEVEL BAROCLINIC ZONE RUNNING
FROM THE TWIN CITIES INTO CENTRAL LOWER MICHIGAN. HIGH RES NEAR
TERM GUIDANCE SHOWS SOME INTERESTING SOLUTIONS IN TERMS OF
WINDS/BOUNDARY PLACEMENT INTO THE AFTERNOON. THE RAP AND THE HRRR
BOTH DEPICT THE CURRENT EXPANSE OF NORTHEAST WINDS BEHIND THE
FIRST BOUNDARY BUT THEN TURN WINDS ACROSS MUCH OF THE AREA
SOUTHWESTERLY THIS MORNING WITH A BOUNDARY SETTING UP FROM NEAR
ROCKFORD TO JOLIET TO RENSSELAER OR SO. THIS IS AN INTERESTING
PROGRESSION OF THINGS IF THIS INITIAL BOUNDARY WERE THE TRUE COLD
FRONT. LOCAL WRF SHOWS A SIMILAR THOUGH LESS PRONOUNCED TREND.
ASSUMING THIS BOUNDARY IS THE COLD FRONT IT IS POSSIBLE THAT IT
DOES MOVE BACK NORTHWARD INTO THE MIDDLE OF THE DAY IN RESPONSE TO
THE UPPER TROUGH MOVING TOWARD THE MID/UPPER MISSISSIPPI RIVER
VALLEY GIVEN THAT THE WESTERN EXTENT OF THE FRONT IS IN NORTHWEST
IOWA CLOSER TO WHERE THE UPPER TROUGH AXIS IS NOW. ANOTHER
SCENARIO IS THAT THE INITIAL BOUNDARY WAS SOME SORT OF SHALLOW
OUTFLOW WHICH MIXES OUT THIS MORNING AND THE MAIN FRONT IS THE
BOUNDARY CLOSER TO THE CHICAGO AREA DESCRIBED ABOVE. LOOKING AT
THE VAD WIND PROFILES FROM LOT AND MKX THEY SHOW SIMILAR DEPTHS OF
NORTHEAST WINDS SO IT SEEMS THAT THIS IS A LESS LIKELY SCENARIO.
WILL KEEP THE FORECAST MORE OR LESS AS-IS FOR NOW. OTHERWISE...SPOTTY
SHRA/TSRA DEVELOPMENT IS POSSIBLE BUT THE BULK OF THE NEAR TERM
ACTIVITY LOOKS TO REMAIN TO THE NORTH OVER THE NEXT FEW HOURS.
MDB
//PREV DISCUSSION...
322 AM CDT
HEAT AND THUNDER CHANCES REMAIN THE MAIN FORECAST CHALLENGES THIS
MORNING. EARLY MORNING WATER VAPOR IMAGERY SHOWS A LARGE CLOSED
UPPER LOW OVER NORTHERN QUEBEC WITH WEAK RIDGING TO ITS WEST
EXTENDING FROM THE CENTRAL PLAINS NORTHWARD INTO NORTHERN MANITOBA.
SEVERAL SHORTWAVES ARE EMBEDDED WITH THE MORE ZONAL PORTION OF THE
RIDGING OVER THE NORTHERN PLAINS AND UPPER MISSISSIPPI RIVER VALLEY.
THE MOST NOTABLE IS A VORT MAX OVER SOUTH DAKOTA WHICH IS PART OF A
TROUGH AXIS EXTENDING FROM SOUTHERN ALBERTA INTO NORTHERN NEBRASKA
WHICH IS PUSHING EASTWARD. THIS WILL LIKELY AFFECT THE LOCAL
FORECAST COMING UP TONIGHT/THURSDAY MORNING. TO THE WEST A CLOSED
UPPER LOW HAS STALLED OUT OVER THE WESTERN OREGON/CALIFORNIA BORDER.
AT THE SURFACE...AN OUTFLOW BOUNDARY FROM CONVECTION TO THE NORTH
HAD PUSHED DOWN LAKE MICHIGAN AND INTO NORTHEAST ILLINOIS THIS PAST
EVENING TURNING WINDS NORTHEASTERLY. THIS BOUNDARY HAS WASHED OUT
AS EVIDENCED BY SEVERAL SITES BEHIND WHERE IT PASSED HAVING SWITCHED
AROUND TO A SOUTHWEST WIND. THE COOL FRONT IS NOW JUST NORTH OF
FREEPORT AND JUST SOUTH OF MIDWAY AND IS STILL MOVING SOUTHWARD.
THE MOVEMENT OF THIS FRONT AND THE UPPER SHORT WAVES WILL BE THE
MAIN FEATURES OF NOTE FOR THE SHORT TERM.
TODAY...THE COOL FRONTAL POSITION WILL BE ONE OF THE MAIN CHALLENGES
THROUGH THE DAY AND WILL DICTATE THE TEMP AND PRECIP FORECASTS INTO
THIS EVENING. CURRENTLY...PRECIPITATION IS ASSOCIATED WITH THE MID
LEVEL BAROCLINIC ZONE TRAILING NORTH OF THE FRONT FROM THE TWIN
CITIES ACROSS CENTRAL LAKE MICHIGAN AND ARCHING SOUTHEASTWARD ACROSS
CENTRAL LOWER MICHIGAN. ACTIVITY WILL LIKELY FESTER ALONG THIS ZONE
PERIODICALLY THROUGH THE DAY WITH A SLOW SOUTHWARD MOVEMENT OF THE
MID LEVEL TEMP GRADIENT. AT THIS POINT EXPECT THIS TO BE FOCUSED TO
THE NORTH OF THE CWA. CANNOT COMPLETELY RULE OUT ISOLATED
DEVELOPMENT NEAR THE SURFACE FRONT THIS MORNING BUT CHANCES APPEAR
SLIM. LATEST NAM AND GFS PUT THE FRONT...IN A SOMEWHAT INCOHERENT
STATE...OVER THE FAR SOUTHWESTERN CWA BY EARLY AFTERNOON. LOCAL HIGH
RES GUIDANCE IS A LITTLE SLOWER WITH THE BOUNDARY AND THUS FURTHER
NORTH WITH IT FOR THE AFTERNOON. THE LATEST SURFACE ANALYSIS
SUGGESTS THAT THERE IS A WEAK LOW CENTER OVER NORTHEAST IOWA WHICH
THE RAP ALSO DEPICTS. THE RAP SOLUTION OF THE FRONT SLOWING AND
EVEN PUSHING BACK NORTHWARD SOMEWHAT AS THIS LOW CENTER MOVES
EASTWARD IS PLAUSIBLE. DESPITE THE UNCERTAINTY WITH THE FRONTAL
POSITION THROUGH THE DAY...THE BOUNDARY WILL MOVE INTO HIGHER
DEW POINT AIR ALLOWING FOR SOME POOLING OF MOISTURE AHEAD OF IT
THIS AFTERNOON WHICH IS EXPECTED TO RESULT IN STRONG SURFACE BASED
INSTABILITY ALONG AND SOUTH OF THE FRONT. WITH SOME MIXING
EXPECTED MIXED LAYER INSTABILITY WILL BE LOWER BUT STILL
SUFFICIENT TO SUPPORT STORMS. A SHARP INSTABILITY GRADIENT IS
EXPECTED TO SET UP WITH LATEST THINKING HAVING IT RUN FROM ROUGHLY
ROCKFORD DOWN TOWARDS JOLIET AND EASTWARD TOWARDS RENSSELAER
DURING THE AFTERNOON...WITH EXACT PLACEMENT DEPENDENT ON HOW FAR
SOUTH THE FRONT MOVES. BEYOND RATHER BROAD LOW LEVEL CONVERGENCE
ALONG THE FRONT THERE IS NOT MUCH IN THE WAY OF A LARGER SCALE
TRIGGERING MECHANISM BUT CONVECTIVE TEMPERATURES IN THE MID 90S
SHOULD BE ATTAINABLE SO ISOLATED TO SCATTERED DEVELOPMENT IS
PLAUSIBLE. STORMS THAT DO FORM WILL HAVE AT LEAST SOME SEVERE WIND
POTENTIAL GIVEN THE INVERTED V SOUNDING. EXPECT THAT THE BEST
CHANCE FOR OCCURRENCE IS FROM ROUGHLY ROCKFORD TO JOLIET TO
RENSSELAER SOUTHWARD IN LINE WITH THE EXPECTED INSTABILITY
GRADIENT. HOWEVER...THIS THREAT AREA MAY PUSH SOUTHWESTWARD IF THE
FRONT CAN KEEP SOME FORWARD SPEED THOUGH LATE AFTERNOON. TEMPS ARE
THE NEXT ISSUE...AS INDICATED ABOVE HUMIDITY WILL BE HIGHER THAN
TUESDAY AHEAD OF THE FRONT THANKS TO MOISTURE POOLING. WITH HIGHS
STILL EXPECTED TO BE IN THE MID TO EVEN UPPER 90S SOUTH WILL
MAINTAIN THE HEAT ADVISORY...BUT SOME OF THE NORTHERN PORTIONS OF
IT MAY NOT REACH CRITERIA IF THE FRONT REMAINS ON THE MOVE...OF
CONCERN WOULD BE JASPER AND NEWTON COUNTIES. WILL KEEP THE
ADVISORY GOING AS IS AND LET THE DAY SHIFT MONITOR TEMPS AND TRIM
IF NEEDED. HIGHS NORTH OF THE FRONT WILL BE TRICKIER...BUT BE
RELATIVELY COOLER WITH HIGHS IN THE UPPER 80S TO AROUND
90...THOUGH A NORTHEASTERLY WIND OFF THE LAKE WILL PROBABLY KEEP
LAKESHORE AREAS IN THE MID 80S. DO SEE SOME BUST POTENTIAL ACROSS
THESE AREAS WITH SOME CONCERN THAT FORECAST HIGHS MAY BE A BIT
WARM. IT WILL STILL BE HUMID IN THESE AREAS AS WELL BUT BELOW
ADVISORY LEVELS.
TONIGHT AND THURSDAY...LARGER SCALE FORCING INCREASES TONIGHT...MOST
NOTABLY LATE...AS THE MID LEVEL BAROCLINIC ZONE CURRENTLY NORTH OF THE
AREA RE-ORIENTS FROM WEST TO EAST TO NORTHWEST TO SOUTHEAST AND
SETTLES INTO THE AREA. IN ADDITION...THE WAVE NOTED OVER SOUTH
DAKOTA AND ITS ASSOCIATED TROUGH AXIS IS EXPECTED TO REACH THE AREA
AS IT TURNS SOUTHEASTWARD WITH THE UPPER FLOW BUCKLING AS THE LARGE
QUEBEC UPPER LOW MOVES SOUTHWARD. THE WAVE WILL CROSS THE AREA LATE
TONIGHT INTO THURSDAY MORNING AND WILL A HAVE DECENT CHANCE OF
BRINGING CONVECTION ACROSS THE ENTIRE FORECAST AREA. ITS NOT CLEAR
HOW WIDESPREAD COVERAGE WILL BE HOWEVER BUT THIS CHANCE FOR PRECIP
IS DECENT. LOW CHANCES FOR SCATTERED ACTIVITY WILL BE IN PLACE THIS
EVENING ACROSS THE SOUTHWESTERN CWA WITH LITTLE SUPPORT FOR POPS
NORTHEAST DURING THAT TIME...THOUGH THE BAROCLINIC ZONE MAY BE
GENERATING SOME ACTIVITY JUST TO THE NORTHEAST. PRECIP CHANCES WIND
DOWN THURSDAY AFTERNOON...THOUGH LOW CHANCES CONTINUE SOUTH PERHAPS
THROUGH EARLY EVENING BEFORE THE UPPER FORCING EXITS TO THE
SOUTHEAST AND SURFACE HIGH PRESSURE ARRIVES FROM THE NORTH. HIGHS
THURSDAY WILL RANGE FROM THE MID 80S NORTHEAST WITH FLOW OFF THE
LAKE TO AROUND 90 SOUTHWEST...THOUGH TEMPS MAY NOT REACH THESE
LEVELS TIL LATER IN THE AFTERNOON IF PRECIP IS IN PLACE IN THE
MORNING.
FRIDAY THROUGH TUESDAY...SURFACE HIGH PRESSURE WILL BE IN PLACE
FRIDAY WITH THE MAIN UPPER TROUGH ALONG THE EAST COAST AND A BIG
RIDGE OVER THE WESTERN AND CENTRAL U.S...WITH A RIDGE AXIS EXTENDING
NORTHEAST TOWARDS HUDSON BAY AND ANOTHER AIMED NORTHWEST INTO
ALBERTA...WITH A TROUGH PASSING BETWEEN THE TWO OVER NORTHERN
MANITOBA. THIS TROUGH FLATTENS THE EASTERN RIDGE AXIS WHILE A BIG
UPPER LOW ARRIVES OVER WESTERN BRITISH COLUMBIA TO AMPLIFY THE
WESTERN AXIS...THOUGH THERE IS A WEAK TROUGH AHEAD OF IT TO
TEMPORARILY BREAK IT DOWN. THIS RESULTS IN A NORTHWESTERLY FLOW FROM
THE NORTHERN PLAINS INTO THE LOWER GREAT LAKES BY SUNDAY. THE
QUESTION IS HOW FAR SOUTH THIS ACTIVE CORRIDOR OF FLOW WILL BE
PLACED. THE GFS KEEPS THE LOCAL AREA IN THE PATH OF WEAK SHORTWAVES
WHILE THE ECMWF...WHICH IS VERY SIMILAR IN THE OVERALL
PATTERN...KEEPS THE WAVE TRAIN A LITTLE FURTHER NORTHEAST OF HERE
INTO EARLY NEXT WEEK. FRIDAY LOOKS LIKE A RELATIVELY PLEASANT DAY
WITH SURFACE HIGH PRESSURE KEEPING A NORTHEAST WIND IN PLACE AND A
CORRIDOR OF COOLER MID LEVEL AIR...H85 TEMPS AROUND 14C...IN PLACE
BEHIND THE DEPARTING UPPER TROUGH. THIS SHOULD LEAD TO HIGHS IN THE
MID TO UPPER 80S...THOUGH SOME WESTERN AREAS COULD AGAIN TOUCH 90.
SATURDAY STILL LOOKS TO BE DRY BUT THE ABOVE BECOMES MORE OF AN
ISSUE FROM SUNDAY AND BEYOND. POP CHANCES WOULD LIKELY BE LOW
ANYWAYS GIVEN THE NATURE OF THESE EMBEDDED IMPULSES SO WILL
GENERALLY KEEP THE FORECAST DRY FOR NOW. TEMPS WILL BEGIN TO WARM
AGAIN SATURDAY AND SUNDAY...WITH SOME POTENTIAL FOR A BIGGER WARM UP
EARLY NEXT WEEK WITH THE GFS AND ECMWF PAINTING LOW 20S H85 TEMPS AT
VARIOUS TIMES. OVERALL FORECAST CONFIDENCE IN PRECIP POTENTIAL IS
LOW AND LITTLE BIT HIGHER IN TERMS OF A WARMING TREND CONTINUING
INTO EARLY NEXT WEEK.
MDB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* ISO SHRA/TSRA DEVELOPING ARND 19Z THROUGH 21-22Z.
* NE WINDS THRU SUNSET...WINDS VEERING SE/S OVERNIGHT.
* ADDTL SHRA/TSRA PSBL ARND DAYBREAK.
BEACHLER
//DISCUSSION...UPDATED 18Z...
VISIBLE IMAGERY THIS AFTN WAS DEPICTING SOME BUILDING CUMULUS
CLOUDS ACROSS NORTHERN IL/NORTHWEST IN. ADDTL DEVELOPMENT WAS
NOTED FURTHER EAST. A FRONTAL BOUNDARY WAS ORIENTED FROM RFD SE
THRU JOT. WINDS NE OF THIS BNDRY WERE FROM THE NE...WHILE WINDS SW
OF THIS WERE SOUTHERLY. GUIDANCE CONTINUES TO SHOW THIS AS THE
FOCAL POINT FOR ISO SHRA/TSRA ARND 19-20Z...THEN CONTINUE THRU
22-23Z. COVERAGE SHUD REMAIN MINIMAL. WINDS WILL THEN VEER SE THIS
EVE/OVERNIGHT...WITH A SECOND AREA OF CONVECTION PSBLY EARLY THUR
MORNING. GUIDANCE HAS CONTINUED TO FOCUS THIS SECOND AREA OF
DEVELOPMENT TOWARDS THE 11-15Z TIMEFRAME...THEN PUSH THE BULK OF
THE LOW/MID LVL MOISTURE EAST...RESULTING IN DRY WEATHER FOR THE
REMAINDER OF THE AFTN THUR. WINDS WILL THEN BACK EAST AND
EVENTUALLY NORTHEAST AS A WEAK LOW PRESSURE SLIDES EAST ACROSS
NORTHERN IL/NORTHWEST IN.
BEACHLER
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH CONFIDENCE IN WIND FORECAST.
* MEDIUM CONFIDENCE IN TS COVERAGE AND TIMING.
* MEDIUM CONFIDENCE IN ENDING OF TS/SHRA.
* LOW CONFIDENCE IN PRECIP DEVELOPMENT OVERNIGHT INTO EARLY THUR.
BEACHLER
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT...
FRI THROUGH TUE...VFR. NO SIG WX.
TRS
&&
.MARINE...
432 AM CDT
A COLD FRONT TRAILS FROM LOW PRESSURE OVER THE GULF OF ST.
LAWRENCE ACROSS SOUTHERN LOWER MI...FAR SOUTHERN LAKE MI AND FAR
NORTHERN IL EARLY THIS MORNING. THE COLD FRONT WILL CONTINUE TO
MOVE SLOWLY SOUTHWARD TODAY AND TONIGHT...EXTENDING FROM CENTRAL
IN ACROSS IL TO CENTRAL IA BY THURSDAY MORNING. HIGH PRESSURE OF
WILL BUILD SE FROM HUDSON BAY AND ONTARIO BEHIND THE COLD
FRONT...SPREADING ACROSS THE GREAT LAKES TODAY AND TONIGHT. LOW
PRESSURE WILL RIDE ALONG THE FRONTAL BOUNDARY FROM IA TO THE
UPPER OH VALLEY DURING THU WHILE A RIDGE OF HIGH PRESSURE REMAINS
OVER THE GREAT LAKES. LOW PRESSURE WILL BE TRACKING E FROM CENTRAL
CANADA TO HUDSON BAY THU NIGHT THROUGH FRI NIGHT WHILE THE RIDGE
OVER THE GREAT LAKES SHIFTS S OVER THE NORTHEASTERN U.S. AND THE
MIDWEST. THE COLD FRONT TRAILING FROM THE CANADIAN LOW WILL DROP S
ACROSS NORTHERN LAKE MI SUN NIGHT.
TRS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...HEAT ADVISORY...ILZ019-ILZ021-ILZ023-ILZ032-ILZ033-ILZ039 UNTIL
7 PM WEDNESDAY.
IN...HEAT ADVISORY...INZ010-INZ011-INZ019 UNTIL 7 PM WEDNESDAY.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1106 AM CDT WED JUL 18 2012
.DISCUSSION...
558 AM CDT
LATEST RADAR/SURFACE OBS SHOW FRONTAL BOUNDARY STRETCHING FROM
NEAR DUBUQUE TO MORRIS TO NEAR VALPARAISO AT 530 AM WHICH HAD
SURGED SOUTHWARD OVER THE LAST HOUR. RADAR MOSAIC SHOWS ANOTHER
BOUNDARY FROM NEAR JANESVILLE TO CHICAGO. THIS BOUNDARY IS
COINCIDENT WITH SPOTTY CONVECTION NEAR MADISON AND A FEW SMALL
CELLS OVER SOUTHERN LAKE MICHIGAN. THE MAIN AREA OF CONVECTION
REMAINS MORE CLOSELY TIED TO THE MID LEVEL BAROCLINIC ZONE RUNNING
FROM THE TWIN CITIES INTO CENTRAL LOWER MICHIGAN. HIGH RES NEAR
TERM GUIDANCE SHOWS SOME INTERESTING SOLUTIONS IN TERMS OF
WINDS/BOUNDARY PLACEMENT INTO THE AFTERNOON. THE RAP AND THE HRRR
BOTH DEPICT THE CURRENT EXPANSE OF NORTHEAST WINDS BEHIND THE
FIRST BOUNDARY BUT THEN TURN WINDS ACROSS MUCH OF THE AREA
SOUTHWESTERLY THIS MORNING WITH A BOUNDARY SETTING UP FROM NEAR
ROCKFORD TO JOLIET TO RENSSELAER OR SO. THIS IS AN INTERESTING
PROGRESSION OF THINGS IF THIS INITIAL BOUNDARY WERE THE TRUE COLD
FRONT. LOCAL WRF SHOWS A SIMILAR THOUGH LESS PRONOUNCED TREND.
ASSUMING THIS BOUNDARY IS THE COLD FRONT IT IS POSSIBLE THAT IT
DOES MOVE BACK NORTHWARD INTO THE MIDDLE OF THE DAY IN RESPONSE TO
THE UPPER TROUGH MOVING TOWARD THE MID/UPPER MISSISSIPPI RIVER
VALLEY GIVEN THAT THE WESTERN EXTENT OF THE FRONT IS IN NORTHWEST
IOWA CLOSER TO WHERE THE UPPER TROUGH AXIS IS NOW. ANOTHER
SCENARIO IS THAT THE INITIAL BOUNDARY WAS SOME SORT OF SHALLOW
OUTFLOW WHICH MIXES OUT THIS MORNING AND THE MAIN FRONT IS THE
BOUNDARY CLOSER TO THE CHICAGO AREA DESCRIBED ABOVE. LOOKING AT
THE VAD WIND PROFILES FROM LOT AND MKX THEY SHOW SIMILAR DEPTHS OF
NORTHEAST WINDS SO IT SEEMS THAT THIS IS A LESS LIKELY SCENARIO.
WILL KEEP THE FORECAST MORE OR LESS AS-IS FOR NOW. OTHERWISE...SPOTTY
SHRA/TSRA DEVELOPMENT IS POSSIBLE BUT THE BULK OF THE NEAR TERM
ACTIVITY LOOKS TO REMAIN TO THE NORTH OVER THE NEXT FEW HOURS.
MDB
//PREV DISCUSSION...
322 AM CDT
HEAT AND THUNDER CHANCES REMAIN THE MAIN FORECAST CHALLENGES THIS
MORNING. EARLY MORNING WATER VAPOR IMAGERY SHOWS A LARGE CLOSED
UPPER LOW OVER NORTHERN QUEBEC WITH WEAK RIDGING TO ITS WEST
EXTENDING FROM THE CENTRAL PLAINS NORTHWARD INTO NORTHERN MANITOBA.
SEVERAL SHORTWAVES ARE EMBEDDED WITH THE MORE ZONAL PORTION OF THE
RIDGING OVER THE NORTHERN PLAINS AND UPPER MISSISSIPPI RIVER VALLEY.
THE MOST NOTABLE IS A VORT MAX OVER SOUTH DAKOTA WHICH IS PART OF A
TROUGH AXIS EXTENDING FROM SOUTHERN ALBERTA INTO NORTHERN NEBRASKA
WHICH IS PUSHING EASTWARD. THIS WILL LIKELY AFFECT THE LOCAL
FORECAST COMING UP TONIGHT/THURSDAY MORNING. TO THE WEST A CLOSED
UPPER LOW HAS STALLED OUT OVER THE WESTERN OREGON/CALIFORNIA BORDER.
AT THE SURFACE...AN OUTFLOW BOUNDARY FROM CONVECTION TO THE NORTH
HAD PUSHED DOWN LAKE MICHIGAN AND INTO NORTHEAST ILLINOIS THIS PAST
EVENING TURNING WINDS NORTHEASTERLY. THIS BOUNDARY HAS WASHED OUT
AS EVIDENCED BY SEVERAL SITES BEHIND WHERE IT PASSED HAVING SWITCHED
AROUND TO A SOUTHWEST WIND. THE COOL FRONT IS NOW JUST NORTH OF
FREEPORT AND JUST SOUTH OF MIDWAY AND IS STILL MOVING SOUTHWARD.
THE MOVEMENT OF THIS FRONT AND THE UPPER SHORT WAVES WILL BE THE
MAIN FEATURES OF NOTE FOR THE SHORT TERM.
TODAY...THE COOL FRONTAL POSITION WILL BE ONE OF THE MAIN CHALLENGES
THROUGH THE DAY AND WILL DICTATE THE TEMP AND PRECIP FORECASTS INTO
THIS EVENING. CURRENTLY...PRECIPITATION IS ASSOCIATED WITH THE MID
LEVEL BAROCLINIC ZONE TRAILING NORTH OF THE FRONT FROM THE TWIN
CITIES ACROSS CENTRAL LAKE MICHIGAN AND ARCHING SOUTHEASTWARD ACROSS
CENTRAL LOWER MICHIGAN. ACTIVITY WILL LIKELY FESTER ALONG THIS ZONE
PERIODICALLY THROUGH THE DAY WITH A SLOW SOUTHWARD MOVEMENT OF THE
MID LEVEL TEMP GRADIENT. AT THIS POINT EXPECT THIS TO BE FOCUSED TO
THE NORTH OF THE CWA. CANNOT COMPLETELY RULE OUT ISOLATED
DEVELOPMENT NEAR THE SURFACE FRONT THIS MORNING BUT CHANCES APPEAR
SLIM. LATEST NAM AND GFS PUT THE FRONT...IN A SOMEWHAT INCOHERENT
STATE...OVER THE FAR SOUTHWESTERN CWA BY EARLY AFTERNOON. LOCAL HIGH
RES GUIDANCE IS A LITTLE SLOWER WITH THE BOUNDARY AND THUS FURTHER
NORTH WITH IT FOR THE AFTERNOON. THE LATEST SURFACE ANALYSIS
SUGGESTS THAT THERE IS A WEAK LOW CENTER OVER NORTHEAST IOWA WHICH
THE RAP ALSO DEPICTS. THE RAP SOLUTION OF THE FRONT SLOWING AND
EVEN PUSHING BACK NORTHWARD SOMEWHAT AS THIS LOW CENTER MOVES
EASTWARD IS PLAUSIBLE. DESPITE THE UNCERTAINTY WITH THE FRONTAL
POSITION THROUGH THE DAY...THE BOUNDARY WILL MOVE INTO HIGHER
DEW POINT AIR ALLOWING FOR SOME POOLING OF MOISTURE AHEAD OF IT
THIS AFTERNOON WHICH IS EXPECTED TO RESULT IN STRONG SURFACE BASED
INSTABILITY ALONG AND SOUTH OF THE FRONT. WITH SOME MIXING
EXPECTED MIXED LAYER INSTABILITY WILL BE LOWER BUT STILL
SUFFICIENT TO SUPPORT STORMS. A SHARP INSTABILITY GRADIENT IS
EXPECTED TO SET UP WITH LATEST THINKING HAVING IT RUN FROM ROUGHLY
ROCKFORD DOWN TOWARDS JOLIET AND EASTWARD TOWARDS RENSSELAER
DURING THE AFTERNOON...WITH EXACT PLACEMENT DEPENDENT ON HOW FAR
SOUTH THE FRONT MOVES. BEYOND RATHER BROAD LOW LEVEL CONVERGENCE
ALONG THE FRONT THERE IS NOT MUCH IN THE WAY OF A LARGER SCALE
TRIGGERING MECHANISM BUT CONVECTIVE TEMPERATURES IN THE MID 90S
SHOULD BE ATTAINABLE SO ISOLATED TO SCATTERED DEVELOPMENT IS
PLAUSIBLE. STORMS THAT DO FORM WILL HAVE AT LEAST SOME SEVERE WIND
POTENTIAL GIVEN THE INVERTED V SOUNDING. EXPECT THAT THE BEST
CHANCE FOR OCCURRENCE IS FROM ROUGHLY ROCKFORD TO JOLIET TO
RENSSELAER SOUTHWARD IN LINE WITH THE EXPECTED INSTABILITY
GRADIENT. HOWEVER...THIS THREAT AREA MAY PUSH SOUTHWESTWARD IF THE
FRONT CAN KEEP SOME FORWARD SPEED THOUGH LATE AFTERNOON. TEMPS ARE
THE NEXT ISSUE...AS INDICATED ABOVE HUMIDITY WILL BE HIGHER THAN
TUESDAY AHEAD OF THE FRONT THANKS TO MOISTURE POOLING. WITH HIGHS
STILL EXPECTED TO BE IN THE MID TO EVEN UPPER 90S SOUTH WILL
MAINTAIN THE HEAT ADVISORY...BUT SOME OF THE NORTHERN PORTIONS OF
IT MAY NOT REACH CRITERIA IF THE FRONT REMAINS ON THE MOVE...OF
CONCERN WOULD BE JASPER AND NEWTON COUNTIES. WILL KEEP THE
ADVISORY GOING AS IS AND LET THE DAY SHIFT MONITOR TEMPS AND TRIM
IF NEEDED. HIGHS NORTH OF THE FRONT WILL BE TRICKIER...BUT BE
RELATIVELY COOLER WITH HIGHS IN THE UPPER 80S TO AROUND
90...THOUGH A NORTHEASTERLY WIND OFF THE LAKE WILL PROBABLY KEEP
LAKESHORE AREAS IN THE MID 80S. DO SEE SOME BUST POTENTIAL ACROSS
THESE AREAS WITH SOME CONCERN THAT FORECAST HIGHS MAY BE A BIT
WARM. IT WILL STILL BE HUMID IN THESE AREAS AS WELL BUT BELOW
ADVISORY LEVELS.
TONIGHT AND THURSDAY...LARGER SCALE FORCING INCREASES TONIGHT...MOST
NOTABLY LATE...AS THE MID LEVEL BAROCLINIC ZONE CURRENTLY NORTH OF THE
AREA RE-ORIENTS FROM WEST TO EAST TO NORTHWEST TO SOUTHEAST AND
SETTLES INTO THE AREA. IN ADDITION...THE WAVE NOTED OVER SOUTH
DAKOTA AND ITS ASSOCIATED TROUGH AXIS IS EXPECTED TO REACH THE AREA
AS IT TURNS SOUTHEASTWARD WITH THE UPPER FLOW BUCKLING AS THE LARGE
QUEBEC UPPER LOW MOVES SOUTHWARD. THE WAVE WILL CROSS THE AREA LATE
TONIGHT INTO THURSDAY MORNING AND WILL A HAVE DECENT CHANCE OF
BRINGING CONVECTION ACROSS THE ENTIRE FORECAST AREA. ITS NOT CLEAR
HOW WIDESPREAD COVERAGE WILL BE HOWEVER BUT THIS CHANCE FOR PRECIP
IS DECENT. LOW CHANCES FOR SCATTERED ACTIVITY WILL BE IN PLACE THIS
EVENING ACROSS THE SOUTHWESTERN CWA WITH LITTLE SUPPORT FOR POPS
NORTHEAST DURING THAT TIME...THOUGH THE BAROCLINIC ZONE MAY BE
GENERATING SOME ACTIVITY JUST TO THE NORTHEAST. PRECIP CHANCES WIND
DOWN THURSDAY AFTERNOON...THOUGH LOW CHANCES CONTINUE SOUTH PERHAPS
THROUGH EARLY EVENING BEFORE THE UPPER FORCING EXITS TO THE
SOUTHEAST AND SURFACE HIGH PRESSURE ARRIVES FROM THE NORTH. HIGHS
THURSDAY WILL RANGE FROM THE MID 80S NORTHEAST WITH FLOW OFF THE
LAKE TO AROUND 90 SOUTHWEST...THOUGH TEMPS MAY NOT REACH THESE
LEVELS TIL LATER IN THE AFTERNOON IF PRECIP IS IN PLACE IN THE
MORNING.
FRIDAY THROUGH TUESDAY...SURFACE HIGH PRESSURE WILL BE IN PLACE
FRIDAY WITH THE MAIN UPPER TROUGH ALONG THE EAST COAST AND A BIG
RIDGE OVER THE WESTERN AND CENTRAL U.S...WITH A RIDGE AXIS EXTENDING
NORTHEAST TOWARDS HUDSON BAY AND ANOTHER AIMED NORTHWEST INTO
ALBERTA...WITH A TROUGH PASSING BETWEEN THE TWO OVER NORTHERN
MANITOBA. THIS TROUGH FLATTENS THE EASTERN RIDGE AXIS WHILE A BIG
UPPER LOW ARRIVES OVER WESTERN BRITISH COLUMBIA TO AMPLIFY THE
WESTERN AXIS...THOUGH THERE IS A WEAK TROUGH AHEAD OF IT TO
TEMPORARILY BREAK IT DOWN. THIS RESULTS IN A NORTHWESTERLY FLOW FROM
THE NORTHERN PLAINS INTO THE LOWER GREAT LAKES BY SUNDAY. THE
QUESTION IS HOW FAR SOUTH THIS ACTIVE CORRIDOR OF FLOW WILL BE
PLACED. THE GFS KEEPS THE LOCAL AREA IN THE PATH OF WEAK SHORTWAVES
WHILE THE ECMWF...WHICH IS VERY SIMILAR IN THE OVERALL
PATTERN...KEEPS THE WAVE TRAIN A LITTLE FURTHER NORTHEAST OF HERE
INTO EARLY NEXT WEEK. FRIDAY LOOKS LIKE A RELATIVELY PLEASANT DAY
WITH SURFACE HIGH PRESSURE KEEPING A NORTHEAST WIND IN PLACE AND A
CORRIDOR OF COOLER MID LEVEL AIR...H85 TEMPS AROUND 14C...IN PLACE
BEHIND THE DEPARTING UPPER TROUGH. THIS SHOULD LEAD TO HIGHS IN THE
MID TO UPPER 80S...THOUGH SOME WESTERN AREAS COULD AGAIN TOUCH 90.
SATURDAY STILL LOOKS TO BE DRY BUT THE ABOVE BECOMES MORE OF AN
ISSUE FROM SUNDAY AND BEYOND. POP CHANCES WOULD LIKELY BE LOW
ANYWAYS GIVEN THE NATURE OF THESE EMBEDDED IMPULSES SO WILL
GENERALLY KEEP THE FORECAST DRY FOR NOW. TEMPS WILL BEGIN TO WARM
AGAIN SATURDAY AND SUNDAY...WITH SOME POTENTIAL FOR A BIGGER WARM UP
EARLY NEXT WEEK WITH THE GFS AND ECMWF PAINTING LOW 20S H85 TEMPS AT
VARIOUS TIMES. OVERALL FORECAST CONFIDENCE IN PRECIP POTENTIAL IS
LOW AND LITTLE BIT HIGHER IN TERMS OF A WARMING TREND CONTINUING
INTO EARLY NEXT WEEK.
MDB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* PSBL ISOLATED SHRA/TSRA BRUSHING TERMINALS THROUGH EARLY THIS AFTN.
* NE WINDS ARND 6 TO 8 KT THROUGH DURATION OF THE DAY.
BEACHLER
//DISCUSSION...UPDATED 12Z...
OUTFLOW FROM CENTRAL WI THUNDERSTORMS MOVES S OVER SE WI AND
SOUTHERN LAKE MI DURING THE LATE EVENING WITH ANOTHER OUTFLOW
DOING THE SAME DURING THE OVERNIGHT. APPEARS THAT ACTUAL SURFACE
FRONT HAS SLIPPED ACROSS FAR NE IL AROUND SUNRISE WITH RADAR
COMPOSITE SHOWING A BOUNDARY FROM AROUND DOWNTOWN CHI WNW ACROSS
THE WI BORDER N OF RFD AND THEN NORTHWESTWARD TO S OF MSN.
THUNDERSTORMS DEVELOPED IN S CENTRAL WI DURING THE PREDAWN N OF
THE BOUNDARY WHILE ELEVATED THUNDERSTORMS HAVE CONTINUED ACROSS
CENTRAL WI ANS ESE FROM GRB ACROSS CENTRAL LAKE MI AND CENTRAL
LOWER MI.
WESTERN EXTENT OF CENTRAL WI ACTIVITY IS SHOWING A GENERAL
DOWNWARD TREND AS ONE SHORT WAVE MOVES FROM E CENTRAL WI INTO W
CENTRAL WI. FURTHER UPSTREAM...A LARGER AREA OF THUNDERSTORMS WAS
MOVING FROM EASTERN SD INTO W CENTRAL AND SE MN AS A MORE WELL
DEFINED SHORT WAVE PUSHES ENE FROM THE WESTERN DAKOTAS.
SHORTER TERM CONCERN IS PROSPECTS OF THUNDERSTORMS ALONG/NEAR THE
SURFACE FRONT ACROSS NE AND FAR N CENTRAL IL INTO S CENTRAL WI.
MODELS GENERALLY SHOW THE FRONT MAKING A LITTLE FURTHER SOUTHWARD
PROGRESS THIS MORNING TO S OF THE CHI TERMINALS. DUE TO
UNCERTAINTY IN TS TO CONTINUE TO DEVELOP IN ASSOCIATION WITH THE
FRONT HAVE INCLUDED A VCTS IN THE TAFORS FOR THIS AFTERNOON AS
PROBABILITY OF ACTUALLY OCCURRING AND TERMINAL IS LOW.
IN THE OUTER PERIOD OF THE TAFORS CONCERN IS PROSPECTS FOR TS
WITH THE NORTHERN PLAINS SHORT WAVE. THE SHORT WAVE TROUGH AXIS
IS PROGGED TO REACH W CENTRAL WI...SE MN AND EASTERN IA BY 00Z
AND TO DROP ESE ACROSS SOUTHERN WI AS WELL AND NORTHERN AND W
CENTRAL OVERNIGHT. PERSISTENT POST FRONTAL CONVECTION THE LAST
COUPLE DAYS FROM THE NORTHERN PLAINS E ACROSS THE WESTERN GREAT
LAKES HAS BEEN OCCURRING WHERE ELEVATED CAPE HAS BEEN IN PLACE.
WITH MODELS SUGGESTING THAT THIS ELEVATED CAPE WILL SHIFT S WITH
TIME FEEL THERE IS A BETTER CHANCE OF SHOWERS AND THUNDERSHOWERS
AT THE LOCAL TERMINALS DURING THE LATE NIGHT AND EARLY MORNING
HOURS OF THU THUS THE PROB30 NEAR/AROUND SUNRISE THU.
TRS
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* HIGH CONFIDENCE IN WIND FORECAST.
* MEDIUM CONFIDENCE IN TS COVERAGE AND TIMING.
* MEDIUM CONFIDENCE IN ENDING OF TS/SHRA.
* LOW CONFIDENCE IN PRECIP DEVELOPMENT OVERNIGHT INTO EARLY THUR.
BEACHLER
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT...
FRI THROUGH TUE...VFR. NO SIG WX.
TRS
&&
.MARINE...
432 AM CDT
A COLD FRONT TRAILS FROM LOW PRESSURE OVER THE GULF OF ST.
LAWRENCE ACROSS SOUTHERN LOWER MI...FAR SOUTHERN LAKE MI AND FAR
NORTHERN IL EARLY THIS MORNING. THE COLD FRONT WILL CONTINUE TO
MOVE SLOWLY SOUTHWARD TODAY AND TONIGHT...EXTENDING FROM CENTRAL
IN ACROSS IL TO CENTRAL IA BY THURSDAY MORNING. HIGH PRESSURE OF
WILL BUILD SE FROM HUDSON BAY AND ONTARIO BEHIND THE COLD
FRONT...SPREADING ACROSS THE GREAT LAKES TODAY AND TONIGHT. LOW
PRESSURE WILL RIDE ALONG THE FRONTAL BOUNDARY FROM IA TO THE
UPPER OH VALLEY DURING THU WHILE A RIDGE OF HIGH PRESSURE REMAINS
OVER THE GREAT LAKES. LOW PRESSURE WILL BE TRACKING E FROM CENTRAL
CANADA TO HUDSON BAY THU NIGHT THROUGH FRI NIGHT WHILE THE RIDGE
OVER THE GREAT LAKES SHIFTS S OVER THE NORTHEASTERN U.S. AND THE
MIDWEST. THE COLD FRONT TRAILING FROM THE CANADIAN LOW WILL DROP S
ACROSS NORTHERN LAKE MI SUN NIGHT.
TRS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...HEAT ADVISORY...ILZ019-ILZ021-ILZ023-ILZ032-ILZ033-ILZ039 UNTIL
7 PM WEDNESDAY.
IN...HEAT ADVISORY...INZ010-INZ011-INZ019 UNTIL 7 PM WEDNESDAY.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1045 AM CDT WED JUL 18 2012
.DISCUSSION...
ISSUED 1045 AM CDT WED JUL 18 2012
AFTER LOOKING AT THE LATEST RUC...NAM12...4KM WRF MODELS WILL BE
UPDATING THE FORECAST TO INCREASE CHANCES OF SHOWERS AND
THUNDERSTORMS IN EASTERN IL. ALSO RAISED HIGHS A DEGREE OR TWO
ACROSS NORTHERN AREAS THIS AFTERNOON. HIGHS GENERALLY IN THE UPPER
90S TO NEAR 100 DEGREES THIS AFTERNOON WITH HEAT INDICES PEAKING
AROUND 105F...SO WILL CONTINUE THE HEAT ADVISORY ACROSS THE AREA
THROUGH 7 PM TODAY. VERY ISOLATED SHOWERS LATE THIS MORNING SE OF
DECATUR WHILE BRUNT OF CONVECTION SO FAR TODAY HAS BEEN OVER
SOUTHERN LAKE MI INTO LOWER MI AND NORTHERN INDIANA. THIS
CONVECTION CLOSER TIED TO A FRONTAL BOUNDARY OVER NORTHERN IL/IN
WHICH MODELS SLOWLY SAG THIS FRONT SOUTH TOWARD PEORIA THIS EVENING.
A STRONGER SHORT WAVE OVER THE DAKOTAS IS FORECAST TO TRACK ESE
ALONG THE BOUNDARY OVER NORTHERN IL TONIGHT KEEPING HIGHER CHANCES
OF SHOWERS AND THUNDERSTORMS JUST TO OUR NORTH. SPC EXPANDED
SLIGHT RISK OF SEVERE STORMS INTO CENTRAL IL FROM MID AFTERNOON
INTO THIS EVENING WHILE BEST CHANCE OF SEVERE STORMS WILL BE JUST
TO OUR NORTH.
HUETTL
&&
.AVIATION...
ISSUED 649 AM CDT WED JUL 18 2012...FOR THE 12Z TAFS
STORM CHANCES ACROSS CENTRAL ILLINOIS WILL INCREASE AFTER 18Z
BASED ON UPSTREAM EVENTS YESTERDAY NEAR THE APPROACHING COLD
FRONT... AND HRRR AND 4KM WRF OUTPUT FROM LAST NIGHT. TO DIMINISH
THE AMOUNT OF HOURS WITH THUNDER IN THE TAFS...WE KEPT ONLY A
MENTION OF VCSH FROM 18Z-24Z. THE LOCATION AND COVERAGE OF STORMS
WILL BY HIGHLY VARIABLE...AND STORM MOTION WILL BE VERY SLOW
OVERALL. SO THE CHANCE OF ANY STORMS HITTING THE TAF SITES
DIRECTLY MAY BE ON THE LOWER SIDE. THE CU FIELD FORMATIONS LATER
THIS MORNING SHOULD POINT TOWARD STORM LOCATIONS FOR THE 18Z TAFS.
PREVAIL WINDS WILL REMAIN SOUTHWEST BELOW 10KT AS THE COLD FRONT
TO THE NORTH REMAINS A CONVERGENT AREA DRAWING WINDS FROM THE
SOUTH. VISIBILITY WILL REMAIN VFR EXCEPT DURING THUNDERSTORMS. WE
KEPT VFR CONDITIONS FOR THE ENTIRE TAF PERIOD FOR NOW.
SHIMON
&&
.PREV DISCUSSION...
ISSUED 259 AM CDT WED JUL 18 2012
LATEST UPPER AIR ANALYSIS FEATURES A LARGE RIDGE OF HIGH PRESSURE
DOMINATING THE CENTRAL AND SOUTHERN CONUS...WHILE A DEEP LOW SPINS
OVER NORTHERN QUEBEC. SHORT-WAVE TROUGH IS EVIDENT ON WATER VAPOR
IMAGERY EJECTING EASTWARD OUT OF THE NORTHERN ROCKIES. AT THE
SURFACE...MAIN BAROCLINIC ZONE EXTENDS FROM THE SOUTHERN GREAT
LAKES INTO THE NORTHERN PLAINS.
SHORT TERM...TODAY THROUGH FRIDAY
FRONT WILL MAKE SLOW PROGRESS SOUTHWARD TODAY...APPROACHING THE
I-74 CORRIDOR TOWARD EVENING. SCATTERED CONVECTION HAS MAINLY BEEN
OCCURRING ALONG AND NORTH OF THE BOUNDARY OVERNIGHT...AND THINK
THIS TREND WILL CONTINUE TODAY AS WELL. AS A RESULT...HIGHEST POPS
WILL BE CONCENTRATED ACROSS THE FAR NORTHERN KILX CWA THIS
AFTERNOON...WITH RAIN CHANCES DIMINISHING FURTHER SOUTHWEST AWAY
FROM THE BOUNDARY. WITH LITTLE OR NO UPPER SUPPORT...THINK AREAL
COVERAGE OF PRECIP WILL BE RATHER MINIMAL INITIALLY...WITH 30
PERCENT COVERAGE ALONG/NORTH OF I-74. GIVEN RELATIVELY HIGH
PRECIPITABLE WATER VALUES OF 1.50 TO 1.75 AND SLOW STORM
MOVEMENT...ANY CONVECTION THAT FIRES WILL BE CAPABLE OF PRODUCING
LOCALLY HEAVY RAINFALL IN A FEW SPOTS. OUTSIDE OF CONVECTION...IT
WILL BE ANOTHER VERY HOT DAY. HIGH TEMPS WILL BE HELD DOWN A FEW
DEGREES ACROSS THE NORTH DUE TO CLOUDS AND PRECIP...BUT WILL BE
JUST AS HOT OR EVEN HOTTER THAN YESTERDAY ACROSS THE SOUTH. HIGHS
WILL MAINLY BE IN THE MIDDLE TO UPPER 90S...WITH A FEW READINGS
AROUND 100 ALONG AND SOUTHWEST OF A JACKSONVILLE...TO ROBINSON
LINE. RESULTING HEAT INDEX VALUES WILL ONCE AGAIN BE AROUND 105
DEGREES...THEREFORE HEAT ADVISORY WILL CONTINUE THROUGH THE DAY.
SHORT-WAVE CURRENTLY PUSHING INTO THE WESTERN DAKOTAS WILL
APPROACH FROM THE NORTHWEST LATE TONIGHT INTO THURSDAY...PROVIDING
STRONGER SYNOPTIC LIFT AND SOMEWHAT BETTER AREAL COVERAGE OF
PRECIP. NAM12 AND SEVERAL DIFFERENT VERSIONS OF THE WRF ARE SUGGESTING
AN ORGANIZED CLUSTER OF STORMS MAY DEVELOP AHEAD OF THE ADVANCING
UPPER WAVE ACROSS IOWA TONIGHT...THEN SLIDE E/SE INTO NORTHERN
ILLINOIS THURSDAY MORNING. HAVE THEREFORE BUMPED POPS UP TO 40S
ACROSS THE N/NW CWA AFTER MIDNIGHT TONIGHT. MAIN QUESTION FURTHER
SOUTH ACROSS THE REMAINDER OF THE AREA WILL BE IF ADDITIONAL
CONVECTION CAN DEVELOP ALONG THE REMNANTS OF THIS FEATURE OR ALONG
ITS ACCOMPANYING OUTFLOW BOUNDARY THURSDAY AFTERNOON. MOST LIKELY
SCENARIO WOULD RESULT IN RE-DEVELOPMENT OF SCATTERED STORMS ACROSS
EAST-CENTRAL AND SOUTHEAST ILLINOIS. DAY 2 CONVECTIVE OUTLOOK FROM
SPC SUPPORTS THIS THEORY...AS AREAS ALONG/EAST OF I-55 ARE IN A
SLIGHT RISK FOR SEVERE. DUE TO UNCERTAINTIES CONCERNING MCS
DEVELOPMENT TONIGHT AND EVENTUAL LOCATION OF ITS OUTFLOW...WILL
CARRY 40 POPS ACROSS THE BOARD ON THURSDAY.
ONCE THE UPPER WAVE WORKS ITS WAY FURTHER EASTWARD...THE
STATIONARY FRONTAL BOUNDARY WILL GET PUSHED OUT OF THE AREA BY
LATE THURSDAY NIGHT OR FRIDAY MORNING. HAVE ADJUSTED POPS
ACCORDINGLY...WITH LINGERING LOW CHANCES EVERYWHERE THURSDAY
NIGHT...THEN JUST ACROSS THE FAR SOUTHEAST ON FRIDAY. AIRMASS
BEHIND THE FRONT WILL BE SLIGHTLY COOLER/LESS HUMID...RESULTING
IN HIGHS IN THE UPPER 80S AND LOWER 90S ON FRIDAY.
LONG TERM...SATURDAY THROUGH TUESDAY
STILL SOME QUESTION REGARDING EXACT POSITION OF PREVAILING UPPER
RIDGE IN THE EXTENDED...HOWEVER MODEL CONSENSUS KEEPS IT PRETTY
MUCH LOCKED IN PLACE ACROSS THE CENTRAL PLAINS. THIS WILL ENSURE
HEART OF HOTTEST AIRMASS STAYS WEST OF THE MISSISSIPPI RIVER
THROUGH EARLY NEXT WEEK. TEMPS FURTHER EAST ACROSS CENTRAL
ILLINOIS WILL STILL BE VERY HOT...BUT READINGS WILL REMAIN BELOW
100 DEGREES IN THE MIDDLE TO UPPER 90S. AS ANOTHER UPPER LOW MOVES
ACROSS CANADA AND DIGS INTO QUEBEC/NORTHERN NEW ENGLAND BY EARLY
NEXT WEEK...ANOTHER FRONT MAY GET SHUNTED SOUTHWARD TOWARD THE
MIDWEST. GIVEN STRENGTH OF RIDGE...AM SKEPTICAL TO BRING BOUNDARY
AND ASSOCIATED PRECIP CHANCES TOO FAR SOUTHWARD. AS A RESULT...AM
MAINTAINING A HOT/DRY FORECAST THROUGH TUESDAY.
BARNES
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR ILZ027>031-036>038-
040>057-061>063-066>068-071>073.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
918 AM CDT WED JUL 18 2012
.DISCUSSION...
558 AM CDT
LATEST RADAR/SURFACE OBS SHOW FRONTAL BOUNDARY STRETCHING FROM
NEAR DUBUQUE TO MORRIS TO NEAR VALPARAISO AT 530 AM WHICH HAD
SURGED SOUTHWARD OVER THE LAST HOUR. RADAR MOSAIC SHOWS ANOTHER
BOUNDARY FROM NEAR JANESVILLE TO CHICAGO. THIS BOUNDARY IS
COINCIDENT WITH SPOTTY CONVECTION NEAR MADISON AND A FEW SMALL
CELLS OVER SOUTHERN LAKE MICHIGAN. THE MAIN AREA OF CONVECTION
REMAINS MORE CLOSELY TIED TO THE MID LEVEL BAROCLINIC ZONE RUNNING
FROM THE TWIN CITIES INTO CENTRAL LOWER MICHIGAN. HIGH RES NEAR
TERM GUIDANCE SHOWS SOME INTERESTING SOLUTIONS IN TERMS OF
WINDS/BOUNDARY PLACEMENT INTO THE AFTERNOON. THE RAP AND THE HRRR
BOTH DEPICT THE CURRENT EXPANSE OF NORTHEAST WINDS BEHIND THE
FIRST BOUNDARY BUT THEN TURN WINDS ACROSS MUCH OF THE AREA
SOUTHWESTERLY THIS MORNING WITH A BOUNDARY SETTING UP FROM NEAR
ROCKFORD TO JOLIET TO RENSSELAER OR SO. THIS IS AN INTERESTING
PROGRESSION OF THINGS IF THIS INITIAL BOUNDARY WERE THE TRUE COLD
FRONT. LOCAL WRF SHOWS A SIMILAR THOUGH LESS PRONOUNCED TREND.
ASSUMING THIS BOUNDARY IS THE COLD FRONT IT IS POSSIBLE THAT IT
DOES MOVE BACK NORTHWARD INTO THE MIDDLE OF THE DAY IN RESPONSE TO
THE UPPER TROUGH MOVING TOWARD THE MID/UPPER MISSISSIPPI RIVER
VALLEY GIVEN THAT THE WESTERN EXTENT OF THE FRONT IS IN NORTHWEST
IOWA CLOSER TO WHERE THE UPPER TROUGH AXIS IS NOW. ANOTHER
SCENARIO IS THAT THE INITIAL BOUNDARY WAS SOME SORT OF SHALLOW
OUTFLOW WHICH MIXES OUT THIS MORNING AND THE MAIN FRONT IS THE
BOUNDARY CLOSER TO THE CHICAGO AREA DESCRIBED ABOVE. LOOKING AT
THE VAD WIND PROFILES FROM LOT AND MKX THEY SHOW SIMILAR DEPTHS OF
NORTHEAST WINDS SO IT SEEMS THAT THIS IS A LESS LIKELY SCENARIO.
WILL KEEP THE FORECAST MORE OR LESS AS-IS FOR NOW. OTHERWISE...SPOTTY
SHRA/TSRA DEVELOPMENT IS POSSIBLE BUT THE BULK OF THE NEAR TERM
ACTIVITY LOOKS TO REMAIN TO THE NORTH OVER THE NEXT FEW HOURS.
MDB
//PREV DISCUSSION...
322 AM CDT
HEAT AND THUNDER CHANCES REMAIN THE MAIN FORECAST CHALLENGES THIS
MORNING. EARLY MORNING WATER VAPOR IMAGERY SHOWS A LARGE CLOSED
UPPER LOW OVER NORTHERN QUEBEC WITH WEAK RIDGING TO ITS WEST
EXTENDING FROM THE CENTRAL PLAINS NORTHWARD INTO NORTHERN MANITOBA.
SEVERAL SHORTWAVES ARE EMBEDDED WITH THE MORE ZONAL PORTION OF THE
RIDGING OVER THE NORTHERN PLAINS AND UPPER MISSISSIPPI RIVER VALLEY.
THE MOST NOTABLE IS A VORT MAX OVER SOUTH DAKOTA WHICH IS PART OF A
TROUGH AXIS EXTENDING FROM SOUTHERN ALBERTA INTO NORTHERN NEBRASKA
WHICH IS PUSHING EASTWARD. THIS WILL LIKELY AFFECT THE LOCAL
FORECAST COMING UP TONIGHT/THURSDAY MORNING. TO THE WEST A CLOSED
UPPER LOW HAS STALLED OUT OVER THE WESTERN OREGON/CALIFORNIA BORDER.
AT THE SURFACE...AN OUTFLOW BOUNDARY FROM CONVECTION TO THE NORTH
HAD PUSHED DOWN LAKE MICHIGAN AND INTO NORTHEAST ILLINOIS THIS PAST
EVENING TURNING WINDS NORTHEASTERLY. THIS BOUNDARY HAS WASHED OUT
AS EVIDENCED BY SEVERAL SITES BEHIND WHERE IT PASSED HAVING SWITCHED
AROUND TO A SOUTHWEST WIND. THE COOL FRONT IS NOW JUST NORTH OF
FREEPORT AND JUST SOUTH OF MIDWAY AND IS STILL MOVING SOUTHWARD.
THE MOVEMENT OF THIS FRONT AND THE UPPER SHORT WAVES WILL BE THE
MAIN FEATURES OF NOTE FOR THE SHORT TERM.
TODAY...THE COOL FRONTAL POSITION WILL BE ONE OF THE MAIN CHALLENGES
THROUGH THE DAY AND WILL DICTATE THE TEMP AND PRECIP FORECASTS INTO
THIS EVENING. CURRENTLY...PRECIPITATION IS ASSOCIATED WITH THE MID
LEVEL BAROCLINIC ZONE TRAILING NORTH OF THE FRONT FROM THE TWIN
CITIES ACROSS CENTRAL LAKE MICHIGAN AND ARCHING SOUTHEASTWARD ACROSS
CENTRAL LOWER MICHIGAN. ACTIVITY WILL LIKELY FESTER ALONG THIS ZONE
PERIODICALLY THROUGH THE DAY WITH A SLOW SOUTHWARD MOVEMENT OF THE
MID LEVEL TEMP GRADIENT. AT THIS POINT EXPECT THIS TO BE FOCUSED TO
THE NORTH OF THE CWA. CANNOT COMPLETELY RULE OUT ISOLATED
DEVELOPMENT NEAR THE SURFACE FRONT THIS MORNING BUT CHANCES APPEAR
SLIM. LATEST NAM AND GFS PUT THE FRONT...IN A SOMEWHAT INCOHERENT
STATE...OVER THE FAR SOUTHWESTERN CWA BY EARLY AFTERNOON. LOCAL HIGH
RES GUIDANCE IS A LITTLE SLOWER WITH THE BOUNDARY AND THUS FURTHER
NORTH WITH IT FOR THE AFTERNOON. THE LATEST SURFACE ANALYSIS
SUGGESTS THAT THERE IS A WEAK LOW CENTER OVER NORTHEAST IOWA WHICH
THE RAP ALSO DEPICTS. THE RAP SOLUTION OF THE FRONT SLOWING AND
EVEN PUSHING BACK NORTHWARD SOMEWHAT AS THIS LOW CENTER MOVES
EASTWARD IS PLAUSIBLE. DESPITE THE UNCERTAINTY WITH THE FRONTAL
POSITION THROUGH THE DAY...THE BOUNDARY WILL MOVE INTO HIGHER
DEW POINT AIR ALLOWING FOR SOME POOLING OF MOISTURE AHEAD OF IT
THIS AFTERNOON WHICH IS EXPECTED TO RESULT IN STRONG SURFACE BASED
INSTABILITY ALONG AND SOUTH OF THE FRONT. WITH SOME MIXING
EXPECTED MIXED LAYER INSTABILITY WILL BE LOWER BUT STILL
SUFFICIENT TO SUPPORT STORMS. A SHARP INSTABILITY GRADIENT IS
EXPECTED TO SET UP WITH LATEST THINKING HAVING IT RUN FROM ROUGHLY
ROCKFORD DOWN TOWARDS JOLIET AND EASTWARD TOWARDS RENSSELAER
DURING THE AFTERNOON...WITH EXACT PLACEMENT DEPENDENT ON HOW FAR
SOUTH THE FRONT MOVES. BEYOND RATHER BROAD LOW LEVEL CONVERGENCE
ALONG THE FRONT THERE IS NOT MUCH IN THE WAY OF A LARGER SCALE
TRIGGERING MECHANISM BUT CONVECTIVE TEMPERATURES IN THE MID 90S
SHOULD BE ATTAINABLE SO ISOLATED TO SCATTERED DEVELOPMENT IS
PLAUSIBLE. STORMS THAT DO FORM WILL HAVE AT LEAST SOME SEVERE WIND
POTENTIAL GIVEN THE INVERTED V SOUNDING. EXPECT THAT THE BEST
CHANCE FOR OCCURRENCE IS FROM ROUGHLY ROCKFORD TO JOLIET TO
RENSSELAER SOUTHWARD IN LINE WITH THE EXPECTED INSTABILITY
GRADIENT. HOWEVER...THIS THREAT AREA MAY PUSH SOUTHWESTWARD IF THE
FRONT CAN KEEP SOME FORWARD SPEED THOUGH LATE AFTERNOON. TEMPS ARE
THE NEXT ISSUE...AS INDICATED ABOVE HUMIDITY WILL BE HIGHER THAN
TUESDAY AHEAD OF THE FRONT THANKS TO MOISTURE POOLING. WITH HIGHS
STILL EXPECTED TO BE IN THE MID TO EVEN UPPER 90S SOUTH WILL
MAINTAIN THE HEAT ADVISORY...BUT SOME OF THE NORTHERN PORTIONS OF
IT MAY NOT REACH CRITERIA IF THE FRONT REMAINS ON THE MOVE...OF
CONCERN WOULD BE JASPER AND NEWTON COUNTIES. WILL KEEP THE
ADVISORY GOING AS IS AND LET THE DAY SHIFT MONITOR TEMPS AND TRIM
IF NEEDED. HIGHS NORTH OF THE FRONT WILL BE TRICKIER...BUT BE
RELATIVELY COOLER WITH HIGHS IN THE UPPER 80S TO AROUND
90...THOUGH A NORTHEASTERLY WIND OFF THE LAKE WILL PROBABLY KEEP
LAKESHORE AREAS IN THE MID 80S. DO SEE SOME BUST POTENTIAL ACROSS
THESE AREAS WITH SOME CONCERN THAT FORECAST HIGHS MAY BE A BIT
WARM. IT WILL STILL BE HUMID IN THESE AREAS AS WELL BUT BELOW
ADVISORY LEVELS.
TONIGHT AND THURSDAY...LARGER SCALE FORCING INCREASES TONIGHT...MOST
NOTABLY LATE...AS THE MID LEVEL BAROCLINIC ZONE CURRENTLY NORTH OF THE
AREA RE-ORIENTS FROM WEST TO EAST TO NORTHWEST TO SOUTHEAST AND
SETTLES INTO THE AREA. IN ADDITION...THE WAVE NOTED OVER SOUTH
DAKOTA AND ITS ASSOCIATED TROUGH AXIS IS EXPECTED TO REACH THE AREA
AS IT TURNS SOUTHEASTWARD WITH THE UPPER FLOW BUCKLING AS THE LARGE
QUEBEC UPPER LOW MOVES SOUTHWARD. THE WAVE WILL CROSS THE AREA LATE
TONIGHT INTO THURSDAY MORNING AND WILL A HAVE DECENT CHANCE OF
BRINGING CONVECTION ACROSS THE ENTIRE FORECAST AREA. ITS NOT CLEAR
HOW WIDESPREAD COVERAGE WILL BE HOWEVER BUT THIS CHANCE FOR PRECIP
IS DECENT. LOW CHANCES FOR SCATTERED ACTIVITY WILL BE IN PLACE THIS
EVENING ACROSS THE SOUTHWESTERN CWA WITH LITTLE SUPPORT FOR POPS
NORTHEAST DURING THAT TIME...THOUGH THE BAROCLINIC ZONE MAY BE
GENERATING SOME ACTIVITY JUST TO THE NORTHEAST. PRECIP CHANCES WIND
DOWN THURSDAY AFTERNOON...THOUGH LOW CHANCES CONTINUE SOUTH PERHAPS
THROUGH EARLY EVENING BEFORE THE UPPER FORCING EXITS TO THE
SOUTHEAST AND SURFACE HIGH PRESSURE ARRIVES FROM THE NORTH. HIGHS
THURSDAY WILL RANGE FROM THE MID 80S NORTHEAST WITH FLOW OFF THE
LAKE TO AROUND 90 SOUTHWEST...THOUGH TEMPS MAY NOT REACH THESE
LEVELS TIL LATER IN THE AFTERNOON IF PRECIP IS IN PLACE IN THE
MORNING.
FRIDAY THROUGH TUESDAY...SURFACE HIGH PRESSURE WILL BE IN PLACE
FRIDAY WITH THE MAIN UPPER TROUGH ALONG THE EAST COAST AND A BIG
RIDGE OVER THE WESTERN AND CENTRAL U.S...WITH A RIDGE AXIS EXTENDING
NORTHEAST TOWARDS HUDSON BAY AND ANOTHER AIMED NORTHWEST INTO
ALBERTA...WITH A TROUGH PASSING BETWEEN THE TWO OVER NORTHERN
MANITOBA. THIS TROUGH FLATTENS THE EASTERN RIDGE AXIS WHILE A BIG
UPPER LOW ARRIVES OVER WESTERN BRITISH COLUMBIA TO AMPLIFY THE
WESTERN AXIS...THOUGH THERE IS A WEAK TROUGH AHEAD OF IT TO
TEMPORARILY BREAK IT DOWN. THIS RESULTS IN A NORTHWESTERLY FLOW FROM
THE NORTHERN PLAINS INTO THE LOWER GREAT LAKES BY SUNDAY. THE
QUESTION IS HOW FAR SOUTH THIS ACTIVE CORRIDOR OF FLOW WILL BE
PLACED. THE GFS KEEPS THE LOCAL AREA IN THE PATH OF WEAK SHORTWAVES
WHILE THE ECMWF...WHICH IS VERY SIMILAR IN THE OVERALL
PATTERN...KEEPS THE WAVE TRAIN A LITTLE FURTHER NORTHEAST OF HERE
INTO EARLY NEXT WEEK. FRIDAY LOOKS LIKE A RELATIVELY PLEASANT DAY
WITH SURFACE HIGH PRESSURE KEEPING A NORTHEAST WIND IN PLACE AND A
CORRIDOR OF COOLER MID LEVEL AIR...H85 TEMPS AROUND 14C...IN PLACE
BEHIND THE DEPARTING UPPER TROUGH. THIS SHOULD LEAD TO HIGHS IN THE
MID TO UPPER 80S...THOUGH SOME WESTERN AREAS COULD AGAIN TOUCH 90.
SATURDAY STILL LOOKS TO BE DRY BUT THE ABOVE BECOMES MORE OF AN
ISSUE FROM SUNDAY AND BEYOND. POP CHANCES WOULD LIKELY BE LOW
ANYWAYS GIVEN THE NATURE OF THESE EMBEDDED IMPULSES SO WILL
GENERALLY KEEP THE FORECAST DRY FOR NOW. TEMPS WILL BEGIN TO WARM
AGAIN SATURDAY AND SUNDAY...WITH SOME POTENTIAL FOR A BIGGER WARM UP
EARLY NEXT WEEK WITH THE GFS AND ECMWF PAINTING LOW 20S H85 TEMPS AT
VARIOUS TIMES. OVERALL FORECAST CONFIDENCE IN PRECIP POTENTIAL IS
LOW AND LITTLE BIT HIGHER IN TERMS OF A WARMING TREND CONTINUING
INTO EARLY NEXT WEEK.
MDB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* PSBL ISOLATED SHRA/TSRA BRUSHING TERMINALS THROUGH EARLY THIS AFTN.
* NE WINDS ARND 6 TO 8 KT THROUGH DURATION OF THE DAY.
BEACHLER
//DISCUSSION...UPDATED 12Z...
OUTFLOW FROM CENTRAL WI THUNDERSTORMS MOVES S OVER SE WI AND
SOUTHERN LAKE MI DURING THE LATE EVENING WITH ANOTHER OUTFLOW
DOING THE SAME DURING THE OVERNIGHT. APPEARS THAT ACTUAL SURFACE
FRONT HAS SLIPPED ACROSS FAR NE IL AROUND SUNRISE WITH RADAR
COMPOSITE SHOWING A BOUNDARY FROM AROUND DOWNTOWN CHI WNW ACROSS
THE WI BORDER N OF RFD AND THEN NORTHWESTWARD TO S OF MSN.
THUNDERSTORMS DEVELOPED IN S CENTRAL WI DURING THE PREDAWN N OF
THE BOUNDARY WHILE ELEVATED THUNDERSTORMS HAVE CONTINUED ACROSS
CENTRAL WI ANS ESE FROM GRB ACROSS CENTRAL LAKE MI AND CENTRAL
LOWER MI.
WESTERN EXTENT OF CENTRAL WI ACTIVITY IS SHOWING A GENERAL
DOWNWARD TREND AS ONE SHORT WAVE MOVES FROM E CENTRAL WI INTO W
CENTRAL WI. FURTHER UPSTREAM...A LARGER AREA OF THUNDERSTORMS WAS
MOVING FROM EASTERN SD INTO W CENTRAL AND SE MN AS A MORE WELL
DEFINED SHORT WAVE PUSHES ENE FROM THE WESTERN DAKOTAS.
SHORTER TERM CONCERN IS PROSPECTS OF THUNDERSTORMS ALONG/NEAR THE
SURFACE FRONT ACROSS NE AND FAR N CENTRAL IL INTO S CENTRAL WI.
MODELS GENERALLY SHOW THE FRONT MAKING A LITTLE FURTHER SOUTHWARD
PROGRESS THIS MORNING TO S OF THE CHI TERMINALS. DUE TO
UNCERTAINTY IN TS TO CONTINUE TO DEVELOP IN ASSOCIATION WITH THE
FRONT HAVE INCLUDED A VCTS IN THE TAFORS FOR THIS AFTERNOON AS
PROBABILITY OF ACTUALLY OCCURRING AND TERMINAL IS LOW.
IN THE OUTER PERIOD OF THE TAFORS CONCERN IS PROSPECTS FOR TS
WITH THE NORTHERN PLAINS SHORT WAVE. THE SHORT WAVE TROUGH AXIS
IS PROGGED TO REACH W CENTRAL WI...SE MN AND EASTERN IA BY 00Z
AND TO DROP ESE ACROSS SOUTHERN WI AS WELL AND NORTHERN AND W
CENTRAL OVERNIGHT. PERSISTENT POST FRONTAL CONVECTION THE LAST
COUPLE DAYS FROM THE NORTHERN PLAINS E ACROSS THE WESTERN GREAT
LAKES HAS BEEN OCCURRING WHERE ELEVATED CAPE HAS BEEN IN PLACE.
WITH MODELS SUGGESTING THAT THIS ELEVATED CAPE WILL SHIFT S WITH
TIME FEEL THERE IS A BETTER CHANCE OF SHOWERS AND THUNDERSHOWERS
AT THE LOCAL TERMINALS DURING THE LATE NIGHT AND EARLY MORNING
HOURS OF THU THUS THE PROB30 NEAR/AROUND SUNRISE THU.
TRS
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* HIGH CONFIDENCE IN WIND FORECAST.
* MEDIUM CONFIDENCE IN TS COVERAGE AND TIMING.
* MEDIUM CONFIDENCE IN ENDING OF TS/SHRA.
* LOW CONFIDENCE IN PRECIP DEVELOPMENT OVERNIGHT INTO EARLY THUR.
BEACHLER
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT...
FRI THROUGH TUE...VFR. NO SIG WX.
TRS
&&
.MARINE...
432 AM CDT
A COLD FRONT TRAILS FROM LOW PRESSURE OVER THE GULF OF ST.
LAWRENCE ACROSS SOUTHERN LOWER MI...FAR SOUTHERN LAKE MI AND FAR
NORTHERN IL EARLY THIS MORNING. THE COLD FRONT WILL CONTINUE TO
MOVE SLOWLY SOUTHWARD TODAY AND TONIGHT...EXTENDING FROM CENTRAL
IN ACROSS IL TO CENTRAL IA BY THURSDAY MORNING. HIGH PRESSURE OF
WILL BUILD SE FROM HUDSON BAY AND ONTARIO BEHIND THE COLD
FRONT...SPREADING ACROSS THE GREAT LAKES TODAY AND TONIGHT. LOW
PRESSURE WILL RIDE ALONG THE FRONTAL BOUNDARY FROM IA TO THE
UPPER OH VALLEY DURING THU WHILE A RIDGE OF HIGH PRESSURE REMAINS
OVER THE GREAT LAKES. LOW PRESSURE WILL BE TRACKING E FROM CENTRAL
CANADA TO HUDSON BAY THU NIGHT THROUGH FRI NIGHT WHILE THE RIDGE
OVER THE GREAT LAKES SHIFTS S OVER THE NORTHEASTERN U.S. AND THE
MIDWEST. THE COLD FRONT TRAILING FROM THE CANADIAN LOW WILL DROP S
ACROSS NORTHERN LAKE MI SUN NIGHT.
TRS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...HEAT ADVISORY...ILZ019-ILZ021-ILZ023-ILZ032-ILZ033-ILZ039 UNTIL
7 PM WEDNESDAY.
IN...HEAT ADVISORY...INZ010-INZ011-INZ019 UNTIL 7 PM WEDNESDAY.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
723 AM CDT WED JUL 18 2012
.DISCUSSION...
558 AM CDT
LATEST RADAR/SURFACE OBS SHOW FRONTAL BOUNDARY STRETCHING FROM
NEAR DUBUQUE TO MORRIS TO NEAR VALPARAISO AT 530 AM WHICH HAD
SURGED SOUTHWARD OVER THE LAST HOUR. RADAR MOSAIC SHOWS ANOTHER
BOUNDARY FROM NEAR JANESVILLE TO CHICAGO. THIS BOUNDARY IS
COINCIDENT WITH SPOTTY CONVECTION NEAR MADISON AND A FEW SMALL
CELLS OVER SOUTHERN LAKE MICHIGAN. THE MAIN AREA OF CONVECTION
REMAINS MORE CLOSELY TIED TO THE MID LEVEL BAROCLINIC ZONE RUNNING
FROM THE TWIN CITIES INTO CENTRAL LOWER MICHIGAN. HIGH RES NEAR
TERM GUIDANCE SHOWS SOME INTERESTING SOLUTIONS IN TERMS OF
WINDS/BOUNDARY PLACEMENT INTO THE AFTERNOON. THE RAP AND THE HRRR
BOTH DEPICT THE CURRENT EXPANSE OF NORTHEAST WINDS BEHIND THE
FIRST BOUNDARY BUT THEN TURN WINDS ACROSS MUCH OF THE AREA
SOUTHWESTERLY THIS MORNING WITH A BOUNDARY SETTING UP FROM NEAR
ROCKFORD TO JOLIET TO RENSSELAER OR SO. THIS IS AN INTERESTING
PROGRESSION OF THINGS IF THIS INITIAL BOUNDARY WERE THE TRUE COLD
FRONT. LOCAL WRF SHOWS A SIMILAR THOUGH LESS PRONOUNCED TREND.
ASSUMING THIS BOUNDARY IS THE COLD FRONT IT IS POSSIBLE THAT IT
DOES MOVE BACK NORTHWARD INTO THE MIDDLE OF THE DAY IN RESPONSE TO
THE UPPER TROUGH MOVING TOWARD THE MID/UPPER MISSISSIPPI RIVER
VALLEY GIVEN THAT THE WESTERN EXTENT OF THE FRONT IS IN NORTHWEST
IOWA CLOSER TO WHERE THE UPPER TROUGH AXIS IS NOW. ANOTHER
SCENARIO IS THAT THE INITIAL BOUNDARY WAS SOME SORT OF SHALLOW
OUTFLOW WHICH MIXES OUT THIS MORNING AND THE MAIN FRONT IS THE
BOUNDARY CLOSER TO THE CHICAGO AREA DESCRIBED ABOVE. LOOKING AT
THE VAD WIND PROFILES FROM LOT AND MKX THEY SHOW SIMILAR DEPTHS OF
NORTHEAST WINDS SO IT SEEMS THAT THIS IS A LESS LIKELY SCENARIO.
WILL KEEP THE FORECAST MORE OR LESS AS-IS FOR NOW. OTHERWISE...SPOTTY
SHRA/TSRA DEVELOPMENT IS POSSIBLE BUT THE BULK OF THE NEAR TERM
ACTIVITY LOOKS TO REMAIN TO THE NORTH OVER THE NEXT FEW HOURS.
MDB
//PREV DISCUSSION...
322 AM CDT
HEAT AND THUNDER CHANCES REMAIN THE MAIN FORECAST CHALLENGES THIS
MORNING. EARLY MORNING WATER VAPOR IMAGERY SHOWS A LARGE CLOSED
UPPER LOW OVER NORTHERN QUEBEC WITH WEAK RIDGING TO ITS WEST
EXTENDING FROM THE CENTRAL PLAINS NORTHWARD INTO NORTHERN MANITOBA.
SEVERAL SHORTWAVES ARE EMBEDDED WITH THE MORE ZONAL PORTION OF THE
RIDGING OVER THE NORTHERN PLAINS AND UPPER MISSISSIPPI RIVER VALLEY.
THE MOST NOTABLE IS A VORT MAX OVER SOUTH DAKOTA WHICH IS PART OF A
TROUGH AXIS EXTENDING FROM SOUTHERN ALBERTA INTO NORTHERN NEBRASKA
WHICH IS PUSHING EASTWARD. THIS WILL LIKELY AFFECT THE LOCAL
FORECAST COMING UP TONIGHT/THURSDAY MORNING. TO THE WEST A CLOSED
UPPER LOW HAS STALLED OUT OVER THE WESTERN OREGON/CALIFORNIA BORDER.
AT THE SURFACE...AN OUTFLOW BOUNDARY FROM CONVECTION TO THE NORTH
HAD PUSHED DOWN LAKE MICHIGAN AND INTO NORTHEAST ILLINOIS THIS PAST
EVENING TURNING WINDS NORTHEASTERLY. THIS BOUNDARY HAS WASHED OUT
AS EVIDENCED BY SEVERAL SITES BEHIND WHERE IT PASSED HAVING SWITCHED
AROUND TO A SOUTHWEST WIND. THE COOL FRONT IS NOW JUST NORTH OF
FREEPORT AND JUST SOUTH OF MIDWAY AND IS STILL MOVING SOUTHWARD.
THE MOVEMENT OF THIS FRONT AND THE UPPER SHORT WAVES WILL BE THE
MAIN FEATURES OF NOTE FOR THE SHORT TERM.
TODAY...THE COOL FRONTAL POSITION WILL BE ONE OF THE MAIN CHALLENGES
THROUGH THE DAY AND WILL DICTATE THE TEMP AND PRECIP FORECASTS INTO
THIS EVENING. CURRENTLY...PRECIPITATION IS ASSOCIATED WITH THE MID
LEVEL BAROCLINIC ZONE TRAILING NORTH OF THE FRONT FROM THE TWIN
CITIES ACROSS CENTRAL LAKE MICHIGAN AND ARCHING SOUTHEASTWARD ACROSS
CENTRAL LOWER MICHIGAN. ACTIVITY WILL LIKELY FESTER ALONG THIS ZONE
PERIODICALLY THROUGH THE DAY WITH A SLOW SOUTHWARD MOVEMENT OF THE
MID LEVEL TEMP GRADIENT. AT THIS POINT EXPECT THIS TO BE FOCUSED TO
THE NORTH OF THE CWA. CANNOT COMPLETELY RULE OUT ISOLATED
DEVELOPMENT NEAR THE SURFACE FRONT THIS MORNING BUT CHANCES APPEAR
SLIM. LATEST NAM AND GFS PUT THE FRONT...IN A SOMEWHAT INCOHERENT
STATE...OVER THE FAR SOUTHWESTERN CWA BY EARLY AFTERNOON. LOCAL HIGH
RES GUIDANCE IS A LITTLE SLOWER WITH THE BOUNDARY AND THUS FURTHER
NORTH WITH IT FOR THE AFTERNOON. THE LATEST SURFACE ANALYSIS
SUGGESTS THAT THERE IS A WEAK LOW CENTER OVER NORTHEAST IOWA WHICH
THE RAP ALSO DEPICTS. THE RAP SOLUTION OF THE FRONT SLOWING AND
EVEN PUSHING BACK NORTHWARD SOMEWHAT AS THIS LOW CENTER MOVES
EASTWARD IS PLAUSIBLE. DESPITE THE UNCERTAINTY WITH THE FRONTAL
POSITION THROUGH THE DAY...THE BOUNDARY WILL MOVE INTO HIGHER
DEW POINT AIR ALLOWING FOR SOME POOLING OF MOISTURE AHEAD OF IT
THIS AFTERNOON WHICH IS EXPECTED TO RESULT IN STRONG SURFACE BASED
INSTABILITY ALONG AND SOUTH OF THE FRONT. WITH SOME MIXING
EXPECTED MIXED LAYER INSTABILITY WILL BE LOWER BUT STILL
SUFFICIENT TO SUPPORT STORMS. A SHARP INSTABILITY GRADIENT IS
EXPECTED TO SET UP WITH LATEST THINKING HAVING IT RUN FROM ROUGHLY
ROCKFORD DOWN TOWARDS JOLIET AND EASTWARD TOWARDS RENSSELAER
DURING THE AFTERNOON...WITH EXACT PLACEMENT DEPENDENT ON HOW FAR
SOUTH THE FRONT MOVES. BEYOND RATHER BROAD LOW LEVEL CONVERGENCE
ALONG THE FRONT THERE IS NOT MUCH IN THE WAY OF A LARGER SCALE
TRIGGERING MECHANISM BUT CONVECTIVE TEMPERATURES IN THE MID 90S
SHOULD BE ATTAINABLE SO ISOLATED TO SCATTERED DEVELOPMENT IS
PLAUSIBLE. STORMS THAT DO FORM WILL HAVE AT LEAST SOME SEVERE WIND
POTENTIAL GIVEN THE INVERTED V SOUNDING. EXPECT THAT THE BEST
CHANCE FOR OCCURRENCE IS FROM ROUGHLY ROCKFORD TO JOLIET TO
RENSSELAER SOUTHWARD IN LINE WITH THE EXPECTED INSTABILITY
GRADIENT. HOWEVER...THIS THREAT AREA MAY PUSH SOUTHWESTWARD IF THE
FRONT CAN KEEP SOME FORWARD SPEED THOUGH LATE AFTERNOON. TEMPS ARE
THE NEXT ISSUE...AS INDICATED ABOVE HUMIDITY WILL BE HIGHER THAN
TUESDAY AHEAD OF THE FRONT THANKS TO MOISTURE POOLING. WITH HIGHS
STILL EXPECTED TO BE IN THE MID TO EVEN UPPER 90S SOUTH WILL
MAINTAIN THE HEAT ADVISORY...BUT SOME OF THE NORTHERN PORTIONS OF
IT MAY NOT REACH CRITERIA IF THE FRONT REMAINS ON THE MOVE...OF
CONCERN WOULD BE JASPER AND NEWTON COUNTIES. WILL KEEP THE
ADVISORY GOING AS IS AND LET THE DAY SHIFT MONITOR TEMPS AND TRIM
IF NEEDED. HIGHS NORTH OF THE FRONT WILL BE TRICKIER...BUT BE
RELATIVELY COOLER WITH HIGHS IN THE UPPER 80S TO AROUND
90...THOUGH A NORTHEASTERLY WIND OFF THE LAKE WILL PROBABLY KEEP
LAKESHORE AREAS IN THE MID 80S. DO SEE SOME BUST POTENTIAL ACROSS
THESE AREAS WITH SOME CONCERN THAT FORECAST HIGHS MAY BE A BIT
WARM. IT WILL STILL BE HUMID IN THESE AREAS AS WELL BUT BELOW
ADVISORY LEVELS.
TONIGHT AND THURSDAY...LARGER SCALE FORCING INCREASES TONIGHT...MOST
NOTABLY LATE...AS THE MID LEVEL BAROCLINIC ZONE CURRENTLY NORTH OF THE
AREA RE-ORIENTS FROM WEST TO EAST TO NORTHWEST TO SOUTHEAST AND
SETTLES INTO THE AREA. IN ADDITION...THE WAVE NOTED OVER SOUTH
DAKOTA AND ITS ASSOCIATED TROUGH AXIS IS EXPECTED TO REACH THE AREA
AS IT TURNS SOUTHEASTWARD WITH THE UPPER FLOW BUCKLING AS THE LARGE
QUEBEC UPPER LOW MOVES SOUTHWARD. THE WAVE WILL CROSS THE AREA LATE
TONIGHT INTO THURSDAY MORNING AND WILL A HAVE DECENT CHANCE OF
BRINGING CONVECTION ACROSS THE ENTIRE FORECAST AREA. ITS NOT CLEAR
HOW WIDESPREAD COVERAGE WILL BE HOWEVER BUT THIS CHANCE FOR PRECIP
IS DECENT. LOW CHANCES FOR SCATTERED ACTIVITY WILL BE IN PLACE THIS
EVENING ACROSS THE SOUTHWESTERN CWA WITH LITTLE SUPPORT FOR POPS
NORTHEAST DURING THAT TIME...THOUGH THE BAROCLINIC ZONE MAY BE
GENERATING SOME ACTIVITY JUST TO THE NORTHEAST. PRECIP CHANCES WIND
DOWN THURSDAY AFTERNOON...THOUGH LOW CHANCES CONTINUE SOUTH PERHAPS
THROUGH EARLY EVENING BEFORE THE UPPER FORCING EXITS TO THE
SOUTHEAST AND SURFACE HIGH PRESSURE ARRIVES FROM THE NORTH. HIGHS
THURSDAY WILL RANGE FROM THE MID 80S NORTHEAST WITH FLOW OFF THE
LAKE TO AROUND 90 SOUTHWEST...THOUGH TEMPS MAY NOT REACH THESE
LEVELS TIL LATER IN THE AFTERNOON IF PRECIP IS IN PLACE IN THE
MORNING.
FRIDAY THROUGH TUESDAY...SURFACE HIGH PRESSURE WILL BE IN PLACE
FRIDAY WITH THE MAIN UPPER TROUGH ALONG THE EAST COAST AND A BIG
RIDGE OVER THE WESTERN AND CENTRAL U.S...WITH A RIDGE AXIS EXTENDING
NORTHEAST TOWARDS HUDSON BAY AND ANOTHER AIMED NORTHWEST INTO
ALBERTA...WITH A TROUGH PASSING BETWEEN THE TWO OVER NORTHERN
MANITOBA. THIS TROUGH FLATTENS THE EASTERN RIDGE AXIS WHILE A BIG
UPPER LOW ARRIVES OVER WESTERN BRITISH COLUMBIA TO AMPLIFY THE
WESTERN AXIS...THOUGH THERE IS A WEAK TROUGH AHEAD OF IT TO
TEMPORARILY BREAK IT DOWN. THIS RESULTS IN A NORTHWESTERLY FLOW FROM
THE NORTHERN PLAINS INTO THE LOWER GREAT LAKES BY SUNDAY. THE
QUESTION IS HOW FAR SOUTH THIS ACTIVE CORRIDOR OF FLOW WILL BE
PLACED. THE GFS KEEPS THE LOCAL AREA IN THE PATH OF WEAK SHORTWAVES
WHILE THE ECMWF...WHICH IS VERY SIMILAR IN THE OVERALL
PATTERN...KEEPS THE WAVE TRAIN A LITTLE FURTHER NORTHEAST OF HERE
INTO EARLY NEXT WEEK. FRIDAY LOOKS LIKE A RELATIVELY PLEASANT DAY
WITH SURFACE HIGH PRESSURE KEEPING A NORTHEAST WIND IN PLACE AND A
CORRIDOR OF COOLER MID LEVEL AIR...H85 TEMPS AROUND 14C...IN PLACE
BEHIND THE DEPARTING UPPER TROUGH. THIS SHOULD LEAD TO HIGHS IN THE
MID TO UPPER 80S...THOUGH SOME WESTERN AREAS COULD AGAIN TOUCH 90.
SATURDAY STILL LOOKS TO BE DRY BUT THE ABOVE BECOMES MORE OF AN
ISSUE FROM SUNDAY AND BEYOND. POP CHANCES WOULD LIKELY BE LOW
ANYWAYS GIVEN THE NATURE OF THESE EMBEDDED IMPULSES SO WILL
GENERALLY KEEP THE FORECAST DRY FOR NOW. TEMPS WILL BEGIN TO WARM
AGAIN SATURDAY AND SUNDAY...WITH SOME POTENTIAL FOR A BIGGER WARM UP
EARLY NEXT WEEK WITH THE GFS AND ECMWF PAINTING LOW 20S H85 TEMPS AT
VARIOUS TIMES. OVERALL FORECAST CONFIDENCE IN PRECIP POTENTIAL IS
LOW AND LITTLE BIT HIGHER IN TERMS OF A WARMING TREND CONTINUING
INTO EARLY NEXT WEEK.
MDB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 12Z...
THREAT OF TS THIS AFTERNOON AND AGAIN EARLY THU MORNING.
TRS
//DISCUSSION...UPDATED 12Z...
OUTFLOW FROM CENTRAL WI THUNDERSTORMS MOVES S OVER SE WI AND
SOUTHERN LAKE MI DURING THE LATE EVENING WITH ANOTHER OUTFLOW
DOING THE SAME DURING THE OVERNIGHT. APPEARS THAT ACTUAL SURFACE
FRONT HAS SLIPPED ACROSS FAR NE IL AROUND SUNRISE WITH RADAR
COMPOSITE SHOWING A BOUNDARY FROM AROUND DOWNTOWN CHI WNW ACROSS
THE WI BORDER N OF RFD AND THEN NORTHWESTWARD TO S OF MSN.
THUNDERSTORMS DEVELOPED IN S CENTRAL WI DURING THE PREDAWN N OF
THE BOUNDARY WHILE ELEVATED THUNDERSTORMS HAVE CONTINUED ACROSS
CENTRAL WI ANS ESE FROM GRB ACROSS CENTRAL LAKE MI AND CENTRAL
LOWER MI.
WESTERN EXTENT OF CENTRAL WI ACTIVITY IS SHOWING A GENERAL
DOWNWARD TREND AS ONE SHORT WAVE MOVES FROM E CENTRAL WI INTO W
CENTRAL WI. FURTHER UPSTREAM...A LARGER AREA OF THUNDERSTORMS WAS
MOVING FROM EASTERN SD INTO W CENTRAL AND SE MN AS A MORE WELL
DEFINED SHORT WAVE PUSHES ENE FROM THE WESTERN DAKOTAS.
SHORTER TERM CONCERN IS PROSPECTS OF THUNDERSTORMS ALONG/NEAR THE
SURFACE FRONT ACROSS NE AND FAR N CENTRAL IL INTO S CENTRAL WI.
MODELS GENERALLY SHOW THE FRONT MAKING A LITTLE FURTHER SOUTHWARD
PROGRESS THIS MORNING TO S OF THE CHI TERMINALS. DUE TO
UNCERTAINTY IN TS TO CONTINUE TO DEVELOP IN ASSOCIATION WITH THE
FRONT HAVE INCLUDED A VCTS IN THE TAFORS FOR THIS AFTERNOON AS
PROBABILITY OF ACTUALLY OCCURRING AND TERMINAL IS LOW.
IN THE OUTER PERIOD OF THE TAFORS CONCERN IS PROSPECTS FOR TS
WITH THE NORTHERN PLAINS SHORT WAVE. THE SHORT WAVE TROUGH AXIS
IS PROGGED TO REACH W CENTRAL WI...SE MN AND EASTERN IA BY 00Z
AND TO DROP ESE ACROSS SOUTHERN WI AS WELL AND NORTHERN AND W
CENTRAL OVERNIGHT. PERSISTENT POST FRONTAL CONVECTION THE LAST
COUPLE DAYS FROM THE NORTHERN PLAINS E ACROSS THE WESTERN GREAT
LAKES HAS BEEN OCCURRING WHERE ELEVATED CAPE HAS BEEN IN PLACE.
WITH MODELS SUGGESTING THAT THIS ELEVATED CAPE WILL SHIFT S WITH
TIME FEEL THERE IS A BETTER CHANCE OF SHOWERS AND THUNDERSHOWERS
AT THE LOCAL TERMINALS DURING THE LATE NIGHT AND EARLY MORNING
HOURS OF THU THUS THE PROB30 NEAR/AROUND SUNRISE THU.
TRS
//ORD AND MDW CONFIDENCE...UPDATED 12Z...
HIGH CONFIDENCE IN WIND FORECAST.
MODERATE CONFIDENCE IN TS IN THE AREA THIS AFTERNOON BUT LOW
CONFIDENCE WILL DIRECTLY AFFECT TERMINALS.
MODERATE CONFIDENCE IS PERIOD OF SHRA AND TSRA OVERNIGHT INTO
EARLY THU MORNING.
TRS
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT...
FRI THROUGH TUE...VFR. NO SIG WX.
TRS
&&
.MARINE...
432 AM CDT
A COLD FRONT TRAILS FROM LOW PRESSURE OVER THE GULF OF ST.
LAWRENCE ACROSS SOUTHERN LOWER MI...FAR SOUTHERN LAKE MI AND FAR
NORTHERN IL EARLY THIS MORNING. THE COLD FRONT WILL CONTINUE TO
MOVE SLOWLY SOUTHWARD TODAY AND TONIGHT...EXTENDING FROM CENTRAL
IN ACROSS IL TO CENTRAL IA BY THURSDAY MORNING. HIGH PRESSURE OF
WILL BUILD SE FROM HUDSON BAY AND ONTARIO BEHIND THE COLD
FRONT...SPREADING ACROSS THE GREAT LAKES TODAY AND TONIGHT. LOW
PRESSURE WILL RIDE ALONG THE FRONTAL BOUNDARY FROM IA TO THE
UPPER OH VALLEY DURING THU WHILE A RIDGE OF HIGH PRESSURE REMAINS
OVER THE GREAT LAKES. LOW PRESSURE WILL BE TRACKING E FROM CENTRAL
CANADA TO HUDSON BAY THU NIGHT THROUGH FRI NIGHT WHILE THE RIDGE
OVER THE GREAT LAKES SHIFTS S OVER THE NORTHEASTERN U.S. AND THE
MIDWEST. THE COLD FRONT TRAILING FROM THE CANADIAN LOW WILL DROP S
ACROSS NORTHERN LAKE MI SUN NIGHT.
TRS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...HEAT ADVISORY...ILZ019-ILZ021-ILZ023-ILZ032-ILZ033-ILZ039 UNTIL
7 PM WEDNESDAY.
IN...HEAT ADVISORY...INZ010-INZ011-INZ019 UNTIL 7 PM WEDNESDAY.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
649 AM CDT WED JUL 18 2012
.DISCUSSION...
ISSUED 259 AM CDT WED JUL 18 2012
LATEST UPPER AIR ANALYSIS FEATURES A LARGE RIDGE OF HIGH PRESSURE
DOMINATING THE CENTRAL AND SOUTHERN CONUS...WHILE A DEEP LOW SPINS
OVER NORTHERN QUEBEC. SHORT-WAVE TROUGH IS EVIDENT ON WATER VAPOR
IMAGERY EJECTING EASTWARD OUT OF THE NORTHERN ROCKIES. AT THE
SURFACE...MAIN BAROCLINIC ZONE EXTENDS FROM THE SOUTHERN GREAT
LAKES INTO THE NORTHERN PLAINS.
SHORT TERM...TODAY THROUGH FRIDAY
FRONT WILL MAKE SLOW PROGRESS SOUTHWARD TODAY...APPROACHING THE
I-74 CORRIDOR TOWARD EVENING. SCATTERED CONVECTION HAS MAINLY BEEN
OCCURRING ALONG AND NORTH OF THE BOUNDARY OVERNIGHT...AND THINK
THIS TREND WILL CONTINUE TODAY AS WELL. AS A RESULT...HIGHEST POPS
WILL BE CONCENTRATED ACROSS THE FAR NORTHERN KILX CWA THIS
AFTERNOON...WITH RAIN CHANCES DIMINISHING FURTHER SOUTHWEST AWAY
FROM THE BOUNDARY. WITH LITTLE OR NO UPPER SUPPORT...THINK AREAL
COVERAGE OF PRECIP WILL BE RATHER MINIMAL INITIALLY...WITH 30
PERCENT COVERAGE ALONG/NORTH OF I-74. GIVEN RELATIVELY HIGH
PRECIPITABLE WATER VALUES OF 1.50 TO 1.75 AND SLOW STORM
MOVEMENT...ANY CONVECTION THAT FIRES WILL BE CAPABLE OF PRODUCING
LOCALLY HEAVY RAINFALL IN A FEW SPOTS. OUTSIDE OF CONVECTION...IT
WILL BE ANOTHER VERY HOT DAY. HIGH TEMPS WILL BE HELD DOWN A FEW
DEGREES ACROSS THE NORTH DUE TO CLOUDS AND PRECIP...BUT WILL BE
JUST AS HOT OR EVEN HOTTER THAN YESTERDAY ACROSS THE SOUTH. HIGHS
WILL MAINLY BE IN THE MIDDLE TO UPPER 90S...WITH A FEW READINGS
AROUND 100 ALONG AND SOUTHWEST OF A JACKSONVILLE...TO ROBINSON
LINE. RESULTING HEAT INDEX VALUES WILL ONCE AGAIN BE AROUND 105
DEGREES...THEREFORE HEAT ADVISORY WILL CONTINUE THROUGH THE DAY.
SHORT-WAVE CURRENTLY PUSHING INTO THE WESTERN DAKOTAS WILL
APPROACH FROM THE NORTHWEST LATE TONIGHT INTO THURSDAY...PROVIDING
STRONGER SYNOPTIC LIFT AND SOMEWHAT BETTER AREAL COVERAGE OF
PRECIP. NAM12 AND SEVERAL DIFFERENT VERSIONS OF THE WRF ARE SUGGESTING
AN ORGANIZED CLUSTER OF STORMS MAY DEVELOP AHEAD OF THE ADVANCING
UPPER WAVE ACROSS IOWA TONIGHT...THEN SLIDE E/SE INTO NORTHERN
ILLINOIS THURSDAY MORNING. HAVE THEREFORE BUMPED POPS UP TO 40S
ACROSS THE N/NW CWA AFTER MIDNIGHT TONIGHT. MAIN QUESTION FURTHER
SOUTH ACROSS THE REMAINDER OF THE AREA WILL BE IF ADDITIONAL
CONVECTION CAN DEVELOP ALONG THE REMNANTS OF THIS FEATURE OR ALONG
ITS ACCOMPANYING OUTFLOW BOUNDARY THURSDAY AFTERNOON. MOST LIKELY
SCENARIO WOULD RESULT IN RE-DEVELOPMENT OF SCATTERED STORMS ACROSS
EAST-CENTRAL AND SOUTHEAST ILLINOIS. DAY 2 CONVECTIVE OUTLOOK FROM
SPC SUPPORTS THIS THEORY...AS AREAS ALONG/EAST OF I-55 ARE IN A
SLIGHT RISK FOR SEVERE. DUE TO UNCERTAINTIES CONCERNING MCS
DEVELOPMENT TONIGHT AND EVENTUAL LOCATION OF ITS OUTFLOW...WILL
CARRY 40 POPS ACROSS THE BOARD ON THURSDAY.
ONCE THE UPPER WAVE WORKS ITS WAY FURTHER EASTWARD...THE
STATIONARY FRONTAL BOUNDARY WILL GET PUSHED OUT OF THE AREA BY
LATE THURSDAY NIGHT OR FRIDAY MORNING. HAVE ADJUSTED POPS
ACCORDINGLY...WITH LINGERING LOW CHANCES EVERYWHERE THURSDAY
NIGHT...THEN JUST ACROSS THE FAR SOUTHEAST ON FRIDAY. AIRMASS
BEHIND THE FRONT WILL BE SLIGHTLY COOLER/LESS HUMID...RESULTING
IN HIGHS IN THE UPPER 80S AND LOWER 90S ON FRIDAY.
LONG TERM...SATURDAY THROUGH TUESDAY
STILL SOME QUESTION REGARDING EXACT POSITION OF PREVAILING UPPER
RIDGE IN THE EXTENDED...HOWEVER MODEL CONSENSUS KEEPS IT PRETTY
MUCH LOCKED IN PLACE ACROSS THE CENTRAL PLAINS. THIS WILL ENSURE
HEART OF HOTTEST AIRMASS STAYS WEST OF THE MISSISSIPPI RIVER
THROUGH EARLY NEXT WEEK. TEMPS FURTHER EAST ACROSS CENTRAL
ILLINOIS WILL STILL BE VERY HOT...BUT READINGS WILL REMAIN BELOW
100 DEGREES IN THE MIDDLE TO UPPER 90S. AS ANOTHER UPPER LOW MOVES
ACROSS CANADA AND DIGS INTO QUEBEC/NORTHERN NEW ENGLAND BY EARLY
NEXT WEEK...ANOTHER FRONT MAY GET SHUNTED SOUTHWARD TOWARD THE
MIDWEST. GIVEN STRENGTH OF RIDGE...AM SKEPTICAL TO BRING BOUNDARY
AND ASSOCIATED PRECIP CHANCES TOO FAR SOUTHWARD. AS A RESULT...AM
MAINTAINING A HOT/DRY FORECAST THROUGH TUESDAY.
BARNES
&&
.AVIATION...
ISSUED 649 AM CDT WED JUL 18 2012...FOR THE 12Z TAFS
STORM CHANCES ACROSS CENTRAL ILLINOIS WILL INCREASE AFTER 18Z
BASED ON UPSTREAM EVENTS YESTERDAY NEAR THE APPROACHING COLD
FRONT... AND HRRR AND 4KM WRF OUTPUT FROM LAST NIGHT. TO DIMINISH
THE AMOUNT OF HOURS WITH THUNDER IN THE TAFS...WE KEPT ONLY A
MENTION OF VCSH FROM 18Z-24Z. THE LOCATION AND COVERAGE OF STORMS
WILL BY HIGHLY VARIABLE...AND STORM MOTION WILL BE VERY SLOW
OVERALL. SO THE CHANCE OF ANY STORMS HITTING THE TAF SITES
DIRECTLY MAY BE ON THE LOWER SIDE. THE CU FIELD FORMATIONS LATER
THIS MORNING SHOULD POINT TOWARD STORM LOCATIONS FOR THE 18Z TAFS.
PREVAIL WINDS WILL REMAIN SOUTHWEST BELOW 10KT AS THE COLD FRONT
TO THE NORTH REMAINS A CONVERGENT AREA DRAWING WINDS FROM THE
SOUTH. VISIBILITY WILL REMAIN VFR EXCEPT DURING THUNDERSTORMS. WE
KEPT VFR CONDITIONS FOR THE ENTIRE TAF PERIOD FOR NOW.
SHIMON
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR ILZ027>031-036>038-
040>057-061>063-066>068-071>073.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
602 AM CDT WED JUL 18 2012
.DISCUSSION...
558 AM CDT
LATEST RADAR/SURFACE OBS SHOW FRONTAL BOUNDARY STRETCHING FROM
NEAR DUBUQUE TO MORRIS TO NEAR VALPARAISO AT 530 AM WHICH HAD
SURGED SOUTHWARD OVER THE LAST HOUR. RADAR MOSAIC SHOWS ANOTHER
BOUNDARY FROM NEAR JANESVILLE TO CHICAGO. THIS BOUNDARY IS
COINCIDENT WITH SPOTTY CONVECTION NEAR MADISON AND A FEW SMALL
CELLS OVER SOUTHERN LAKE MICHIGAN. THE MAIN AREA OF CONVECTION
REMAINS MORE CLOSELY TIED TO THE MID LEVEL BAROCLINIC ZONE RUNNING
FROM THE TWIN CITIES INTO CENTRAL LOWER MICHIGAN. HIGH RES NEAR
TERM GUIDANCE SHOWS SOME INTERESTING SOLUTIONS IN TERMS OF
WINDS/BOUNDARY PLACEMENT INTO THE AFTERNOON. THE RAP AND THE HRRR
BOTH DEPICT THE CURRENT EXPANSE OF NORTHEAST WINDS BEHIND THE
FIRST BOUNDARY BUT THEN TURN WINDS ACROSS MUCH OF THE AREA
SOUTHWESTERLY THIS MORNING WITH A BOUNDARY SETTING UP FROM NEAR
ROCKFORD TO JOLIET TO RENSSELAER OR SO. THIS IS AN INTERESTING
PROGRESSION OF THINGS IF THIS INITIAL BOUNDARY WERE THE TRUE COLD
FRONT. LOCAL WRF SHOWS A SIMILAR THOUGH LESS PRONOUNCED TREND.
ASSUMING THIS BOUNDARY IS THE COLD FRONT IT IS POSSIBLE THAT IT
DOES MOVE BACK NORTHWARD INTO THE MIDDLE OF THE DAY IN RESPONSE TO
THE UPPER TROUGH MOVING TOWARD THE MID/UPPER MISSISSIPPI RIVER
VALLEY GIVEN THAT THE WESTERN EXTENT OF THE FRONT IS IN NORTHWEST
IOWA CLOSER TO WHERE THE UPPER TROUGH AXIS IS NOW. ANOTHER
SCENARIO IS THAT THE INITIAL BOUNDARY WAS SOME SORT OF SHALLOW
OUTFLOW WHICH MIXES OUT THIS MORNING AND THE MAIN FRONT IS THE
BOUNDARY CLOSER TO THE CHICAGO AREA DESCRIBED ABOVE. LOOKING AT
THE VAD WIND PROFILES FROM LOT AND MKX THEY SHOW SIMILAR DEPTHS OF
NORTHEAST WINDS SO IT SEEMS THAT THIS IS A LESS LIKELY SCENARIO.
WILL KEEP THE FORECAST MORE OR LESS AS-IS FOR NOW. OTHERWISE...SPOTTY
SHRA/TSRA DEVELOPMENT IS POSSIBLE BUT THE BULK OF THE NEAR TERM
ACTIVITY LOOKS TO REMAIN TO THE NORTH OVER THE NEXT FEW HOURS.
MDB
&&
.PREV DISCUSSION...
322 AM CDT
HEAT AND THUNDER CHANCES REMAIN THE MAIN FORECAST CHALLENGES THIS
MORNING. EARLY MORNING WATER VAPOR IMAGERY SHOWS A LARGE CLOSED
UPPER LOW OVER NORTHERN QUEBEC WITH WEAK RIDGING TO ITS WEST
EXTENDING FROM THE CENTRAL PLAINS NORTHWARD INTO NORTHERN MANITOBA.
SEVERAL SHORTWAVES ARE EMBEDDED WITH THE MORE ZONAL PORTION OF THE
RIDGING OVER THE NORTHERN PLAINS AND UPPER MISSISSIPPI RIVER VALLEY.
THE MOST NOTABLE IS A VORT MAX OVER SOUTH DAKOTA WHICH IS PART OF A
TROUGH AXIS EXTENDING FROM SOUTHERN ALBERTA INTO NORTHERN NEBRASKA
WHICH IS PUSHING EASTWARD. THIS WILL LIKELY AFFECT THE LOCAL
FORECAST COMING UP TONIGHT/THURSDAY MORNING. TO THE WEST A CLOSED
UPPER LOW HAS STALLED OUT OVER THE WESTERN OREGON/CALIFORNIA BORDER.
AT THE SURFACE...AN OUTFLOW BOUNDARY FROM CONVECTION TO THE NORTH
HAD PUSHED DOWN LAKE MICHIGAN AND INTO NORTHEAST ILLINOIS THIS PAST
EVENING TURNING WINDS NORTHEASTERLY. THIS BOUNDARY HAS WASHED OUT
AS EVIDENCED BY SEVERAL SITES BEHIND WHERE IT PASSED HAVING SWITCHED
AROUND TO A SOUTHWEST WIND. THE COOL FRONT IS NOW JUST NORTH OF
FREEPORT AND JUST SOUTH OF MIDWAY AND IS STILL MOVING SOUTHWARD.
THE MOVEMENT OF THIS FRONT AND THE UPPER SHORT WAVES WILL BE THE
MAIN FEATURES OF NOTE FOR THE SHORT TERM.
TODAY...THE COOL FRONTAL POSITION WILL BE ONE OF THE MAIN CHALLENGES
THROUGH THE DAY AND WILL DICTATE THE TEMP AND PRECIP FORECASTS INTO
THIS EVENING. CURRENTLY...PRECIPITATION IS ASSOCIATED WITH THE MID
LEVEL BAROCLINIC ZONE TRAILING NORTH OF THE FRONT FROM THE TWIN
CITIES ACROSS CENTRAL LAKE MICHIGAN AND ARCHING SOUTHEASTWARD ACROSS
CENTRAL LOWER MICHIGAN. ACTIVITY WILL LIKELY FESTER ALONG THIS ZONE
PERIODICALLY THROUGH THE DAY WITH A SLOW SOUTHWARD MOVEMENT OF THE
MID LEVEL TEMP GRADIENT. AT THIS POINT EXPECT THIS TO BE FOCUSED TO
THE NORTH OF THE CWA. CANNOT COMPLETELY RULE OUT ISOLATED
DEVELOPMENT NEAR THE SURFACE FRONT THIS MORNING BUT CHANCES APPEAR
SLIM. LATEST NAM AND GFS PUT THE FRONT...IN A SOMEWHAT INCOHERENT
STATE...OVER THE FAR SOUTHWESTERN CWA BY EARLY AFTERNOON. LOCAL HIGH
RES GUIDANCE IS A LITTLE SLOWER WITH THE BOUNDARY AND THUS FURTHER
NORTH WITH IT FOR THE AFTERNOON. THE LATEST SURFACE ANALYSIS
SUGGESTS THAT THERE IS A WEAK LOW CENTER OVER NORTHEAST IOWA WHICH
THE RAP ALSO DEPICTS. THE RAP SOLUTION OF THE FRONT SLOWING AND
EVEN PUSHING BACK NORTHWARD SOMEWHAT AS THIS LOW CENTER MOVES
EASTWARD IS PLAUSIBLE. DESPITE THE UNCERTAINTY WITH THE FRONTAL
POSITION THROUGH THE DAY...THE BOUNDARY WILL MOVE INTO HIGHER
DEW POINT AIR ALLOWING FOR SOME POOLING OF MOISTURE AHEAD OF IT
THIS AFTERNOON WHICH IS EXPECTED TO RESULT IN STRONG SURFACE BASED
INSTABILITY ALONG AND SOUTH OF THE FRONT. WITH SOME MIXING
EXPECTED MIXED LAYER INSTABILITY WILL BE LOWER BUT STILL
SUFFICIENT TO SUPPORT STORMS. A SHARP INSTABILITY GRADIENT IS
EXPECTED TO SET UP WITH LATEST THINKING HAVING IT RUN FROM ROUGHLY
ROCKFORD DOWN TOWARDS JOLIET AND EASTWARD TOWARDS RENSSELAER
DURING THE AFTERNOON...WITH EXACT PLACEMENT DEPENDENT ON HOW FAR
SOUTH THE FRONT MOVES. BEYOND RATHER BROAD LOW LEVEL CONVERGENCE
ALONG THE FRONT THERE IS NOT MUCH IN THE WAY OF A LARGER SCALE
TRIGGERING MECHANISM BUT CONVECTIVE TEMPERATURES IN THE MID 90S
SHOULD BE ATTAINABLE SO ISOLATED TO SCATTERED DEVELOPMENT IS
PLAUSIBLE. STORMS THAT DO FORM WILL HAVE AT LEAST SOME SEVERE WIND
POTENTIAL GIVEN THE INVERTED V SOUNDING. EXPECT THAT THE BEST
CHANCE FOR OCCURRENCE IS FROM ROUGHLY ROCKFORD TO JOLIET TO
RENSSELAER SOUTHWARD IN LINE WITH THE EXPECTED INSTABILITY
GRADIENT. HOWEVER...THIS THREAT AREA MAY PUSH SOUTHWESTWARD IF THE
FRONT CAN KEEP SOME FORWARD SPEED THOUGH LATE AFTERNOON. TEMPS ARE
THE NEXT ISSUE...AS INDICATED ABOVE HUMIDITY WILL BE HIGHER THAN
TUESDAY AHEAD OF THE FRONT THANKS TO MOISTURE POOLING. WITH HIGHS
STILL EXPECTED TO BE IN THE MID TO EVEN UPPER 90S SOUTH WILL
MAINTAIN THE HEAT ADVISORY...BUT SOME OF THE NORTHERN PORTIONS OF
IT MAY NOT REACH CRITERIA IF THE FRONT REMAINS ON THE MOVE...OF
CONCERN WOULD BE JASPER AND NEWTON COUNTIES. WILL KEEP THE
ADVISORY GOING AS IS AND LET THE DAY SHIFT MONITOR TEMPS AND TRIM
IF NEEDED. HIGHS NORTH OF THE FRONT WILL BE TRICKIER...BUT BE
RELATIVELY COOLER WITH HIGHS IN THE UPPER 80S TO AROUND
90...THOUGH A NORTHEASTERLY WIND OFF THE LAKE WILL PROBABLY KEEP
LAKESHORE AREAS IN THE MID 80S. DO SEE SOME BUST POTENTIAL ACROSS
THESE AREAS WITH SOME CONCERN THAT FORECAST HIGHS MAY BE A BIT
WARM. IT WILL STILL BE HUMID IN THESE AREAS AS WELL BUT BELOW
ADVISORY LEVELS.
TONIGHT AND THURSDAY...LARGER SCALE FORCING INCREASES TONIGHT...MOST
NOTABLY LATE...AS THE MID LEVEL BAROCLINIC ZONE CURRENTLY NORTH OF THE
AREA RE-ORIENTS FROM WEST TO EAST TO NORTHWEST TO SOUTHEAST AND
SETTLES INTO THE AREA. IN ADDITION...THE WAVE NOTED OVER SOUTH
DAKOTA AND ITS ASSOCIATED TROUGH AXIS IS EXPECTED TO REACH THE AREA
AS IT TURNS SOUTHEASTWARD WITH THE UPPER FLOW BUCKLING AS THE LARGE
QUEBEC UPPER LOW MOVES SOUTHWARD. THE WAVE WILL CROSS THE AREA LATE
TONIGHT INTO THURSDAY MORNING AND WILL A HAVE DECENT CHANCE OF
BRINGING CONVECTION ACROSS THE ENTIRE FORECAST AREA. ITS NOT CLEAR
HOW WIDESPREAD COVERAGE WILL BE HOWEVER BUT THIS CHANCE FOR PRECIP
IS DECENT. LOW CHANCES FOR SCATTERED ACTIVITY WILL BE IN PLACE THIS
EVENING ACROSS THE SOUTHWESTERN CWA WITH LITTLE SUPPORT FOR POPS
NORTHEAST DURING THAT TIME...THOUGH THE BAROCLINIC ZONE MAY BE
GENERATING SOME ACTIVITY JUST TO THE NORTHEAST. PRECIP CHANCES WIND
DOWN THURSDAY AFTERNOON...THOUGH LOW CHANCES CONTINUE SOUTH PERHAPS
THROUGH EARLY EVENING BEFORE THE UPPER FORCING EXITS TO THE
SOUTHEAST AND SURFACE HIGH PRESSURE ARRIVES FROM THE NORTH. HIGHS
THURSDAY WILL RANGE FROM THE MID 80S NORTHEAST WITH FLOW OFF THE
LAKE TO AROUND 90 SOUTHWEST...THOUGH TEMPS MAY NOT REACH THESE
LEVELS TIL LATER IN THE AFTERNOON IF PRECIP IS IN PLACE IN THE
MORNING.
FRIDAY THROUGH TUESDAY...SURFACE HIGH PRESSURE WILL BE IN PLACE
FRIDAY WITH THE MAIN UPPER TROUGH ALONG THE EAST COAST AND A BIG
RIDGE OVER THE WESTERN AND CENTRAL U.S...WITH A RIDGE AXIS EXTENDING
NORTHEAST TOWARDS HUDSON BAY AND ANOTHER AIMED NORTHWEST INTO
ALBERTA...WITH A TROUGH PASSING BETWEEN THE TWO OVER NORTHERN
MANITOBA. THIS TROUGH FLATTENS THE EASTERN RIDGE AXIS WHILE A BIG
UPPER LOW ARRIVES OVER WESTERN BRITISH COLUMBIA TO AMPLIFY THE
WESTERN AXIS...THOUGH THERE IS A WEAK TROUGH AHEAD OF IT TO
TEMPORARILY BREAK IT DOWN. THIS RESULTS IN A NORTHWESTERLY FLOW FROM
THE NORTHERN PLAINS INTO THE LOWER GREAT LAKES BY SUNDAY. THE
QUESTION IS HOW FAR SOUTH THIS ACTIVE CORRIDOR OF FLOW WILL BE
PLACED. THE GFS KEEPS THE LOCAL AREA IN THE PATH OF WEAK SHORTWAVES
WHILE THE ECMWF...WHICH IS VERY SIMILAR IN THE OVERALL
PATTERN...KEEPS THE WAVE TRAIN A LITTLE FURTHER NORTHEAST OF HERE
INTO EARLY NEXT WEEK. FRIDAY LOOKS LIKE A RELATIVELY PLEASANT DAY
WITH SURFACE HIGH PRESSURE KEEPING A NORTHEAST WIND IN PLACE AND A
CORRIDOR OF COOLER MID LEVEL AIR...H85 TEMPS AROUND 14C...IN PLACE
BEHIND THE DEPARTING UPPER TROUGH. THIS SHOULD LEAD TO HIGHS IN THE
MID TO UPPER 80S...THOUGH SOME WESTERN AREAS COULD AGAIN TOUCH 90.
SATURDAY STILL LOOKS TO BE DRY BUT THE ABOVE BECOMES MORE OF AN
ISSUE FROM SUNDAY AND BEYOND. POP CHANCES WOULD LIKELY BE LOW
ANYWAYS GIVEN THE NATURE OF THESE EMBEDDED IMPULSES SO WILL
GENERALLY KEEP THE FORECAST DRY FOR NOW. TEMPS WILL BEGIN TO WARM
AGAIN SATURDAY AND SUNDAY...WITH SOME POTENTIAL FOR A BIGGER WARM UP
EARLY NEXT WEEK WITH THE GFS AND ECMWF PAINTING LOW 20S H85 TEMPS AT
VARIOUS TIMES. OVERALL FORECAST CONFIDENCE IN PRECIP POTENTIAL IS
LOW AND LITTLE BIT HIGHER IN TERMS OF A WARMING TREND CONTINUING
INTO EARLY NEXT WEEK.
MDB
&&
.CLIMATE...
305 PM CDT...
RECORDS FOR TODAY JULY 17TH ARE AS FOLLOWS:
CHICAGO RECORD HIGH: 100 /1942/
ROCKFORD RECORD HIGH: 104 /1936/
CHICAGO RECORD WARM LOW: 80 /1878/
ROCKFORD RECORD WARM LOW: 76 /1982/
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
TIMING OF ARRIVAL COLD FRONTAL PASSAGE ACROSS TERMINALS.
POTENTIAL FOR CONVECTIVE ACTIVITY ALONG AND AHEAD OF COLD FRONT
TODAY AS WELL AS ELEVATED CONVECTION POST FRONTAL DURING THE
OVERNIGHT.
TRS
//DISCUSSION...UPDATED 06Z...
KLOT...TORD AND TMDW RADARS SHOWED THE OUTFLOW BOUNDARY THAT
ORIGINATED FROM THUNDERSTORMS OVER E CENTRAL WI AND CENTRAL LAKE
MI CONTINUED TO DROP S DURING THE EVENING FROM NORTHEASTERN TO
SOUTHEASTERN COOK CO. BURNHAM HARBOR AND MDW BRIEFLY SHOWING
LIGHT N-NNE WINDS 04-05Z BUT HAVE ALREADY SWITCHED BACK TO A
LIGHT SW FLOW.
COLD FRONT AT 05Z WAS LOCATED E-W ACROSS SOUTHERN LOWER MI AND
SOUTHERN LAKE MI TO FAR SOUTHEASTERN WI THEN CURVED WNW TO
SOUTHERN MN. MAIN AREA OF CONVECTION WAS FROM E CENTRAL WI ESE
ACROSS LAKE MI TO W CENTRAL LOWER MI. THIS WAS POST FRONTAL WHERE
ELEVATED CAPE STILL IN PLACE AS A SHORT WAVE MOVED ESE FROM MN
ACROSS CENTRAL WI DURING TUE AFTERNOON AND EVENING.
LATEST MODEL RUNS HAVE THE COLD FRONT SINKING S ACROSS THE STATE
LINE DURING THE OVERNIGHT AND EARLY MORNING...AND PUSHING ACROSS
THE CHI AREA TERMINALS AROUND 13Z. WITH ONLY A HOUR OR TWO OF
HEATING BEFORE THE ARRIVAL AND A LACK OF MID OR UPPER LEVEL
SUPPORT TO NOT SEE ANY SIGNIFICANT POTENTIAL FOR CONVECTIVE
DEVELOPMENT BEFORE THE FRONT PASSES BY THE TERMINALS.
UPSTREAM...A FEW SHORT NARROW LINE SEGMENTS OF SHOWERS AND
THUNDERSTORMS WERE OCCURRING FROM W CENTRAL WI ACROSS CENTRAL MN
TO NW SD. THE SE WERE OCCURRING ALONG THE LEADING EDGE OF THE
TIGHT 850HPA THERMAL GRADIENT. THIS THERMAL GRADIENT DOES MIGRATE
SOUTHWARD TODAY BUT MODELS SHOW IT TO MOVING INTO FAR NE IL TIL
THIS AFTERNOON. CANNOT TOTALLY RULE OUT AN ISOLATED OR WIDELY
SCATTERED THUNDERSTORMS ASSOCIATED WITH THIS BAROCLINIC ZONE
DURING THE AFTERNOON AT OR IN THE VC OF THE CHI TERMINALS BUT
LOCATIONS ALONG THE COLD FRONT LOOK TO BE BETTER CANDIDATES FOR
SEEING SIGNIFICANT CONVECTION LATER TODAY WHERE LOW LEVEL DEW
POINT POOLING AND CONVERGENCE MAXIMIZE CAPE VALUES FROM SE TO S
TO SW AND W OF THE CHI AREA.
FURTHER UP STEAM...MORE SHOWERS AND THUNDERSTORMS WERE OCCURRING
IN CENTRAL SD AS A MORE WELL DEFINED SHORT WAVE TROUGH WAS MOVING
E FROM WESTERN SD AND NEB. THE SHORT WAVE TROUGH AXIS IS PROGGED
TO REACH W CENTRAL WI...SE MN AND EASTERN IA BY 00Z AND TO DROP
ESE ACROSS SOUTHERN WI AS WELL AND NORTHERN AND W CENTRAL
OVERNIGHT. THIS WILL BRING A CHANCE OF SHOWERS AND THUNDERSHOWERS
TO THE LOCAL TERMINALS DURING THE LATE NIGHT AND EARLY MORNING
HOURS OF THU.
WITH THE COLD FRONT SLIPPING S OF THE TERMINALS DURING THE FIRST
PART OF TODAY AND THE SOUTHERN PORTION OF A LARGE RIDGE OF HIGH
PRESSURE BUILDING SE OVER THE UPPER GREAT LAKES LOCAL WINDS
EXPECTED TO BE OUT OF THE NE THOUGH GENERALLY AOB 10KT AS
GRADIENT BEHIND THE FRONT IS SHOWN TO BE PRETTY WEAK.
TRS
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
HIGH CONFIDENCE IN FORECAST WIND TRENDS.
MODERATE CONFIDENCE IS CONVECTIVE ACTIVITY TO NOT AFFECT
IMMEDIATE CHI VC TODAY.
TRS
//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...
THURSDAY...CHC TSRA...ELSE VFR.
FRIDAY...VFR.
SATURDAY...VFR.
SUNDAY...VFR.
MONDAY...CHC TSRA...ELSE VFR.
BMD
&&
.MARINE...
432 AM CDT
A COLD FRONT TRAILS FROM LOW PRESSURE OVER THE GULF OF ST.
LAWRENCE ACROSS SOUTHERN LOWER MI...FAR SOUTHERN LAKE MI AND FAR
NORTHERN IL EARLY THIS MORNING. THE COLD FRONT WILL CONTINUE TO
MOVE SLOWLY SOUTHWARD TODAY AND TONIGHT...EXTENDING FROM CENTRAL
IN ACROSS IL TO CENTRAL IA BY THURSDAY MORNING. HIGH PRESSURE OF
WILL BUILD SE FROM HUDSON BAY AND ONTARIO BEHIND THE COLD
FRONT...SPREADING ACROSS THE GREAT LAKES TODAY AND TONIGHT. LOW
PRESSURE WILL RIDE ALONG THE FRONTAL BOUNDARY FROM IA TO THE
UPPER OH VALLEY DURING THU WHILE A RIDGE OF HIGH PRESSURE REMAINS
OVER THE GREAT LAKES. LOW PRESSURE WILL BE TRACKING E FROM CENTRAL
CANADA TO HUDSON BAY THU NIGHT THROUGH FRI NIGHT WHILE THE RIDGE
OVER THE GREAT LAKES SHIFTS S OVER THE NORTHEASTERN U.S. AND THE
MIDWEST. THE COLD FRONT TRAILING FROM THE CANADIAN LOW WILL DROP S
ACROSS NORTHERN LAKE MI SUN NIGHT.
TRS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...HEAT ADVISORY...ILZ019-ILZ021-ILZ023-ILZ032-ILZ033-ILZ039 UNTIL
7 PM WEDNESDAY.
IN...HEAT ADVISORY...INZ010-INZ011-INZ019 UNTIL 7 PM WEDNESDAY.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
433 AM CDT WED JUL 18 2012
.DISCUSSION...
322 AM CDT
HEAT AND THUNDER CHANCES REMAIN THE MAIN FORECAST CHALLENGES THIS
MORNING. EARLY MORNING WATER VAPOR IMAGERY SHOWS A LARGE CLOSED
UPPER LOW OVER NORTHERN QUEBEC WITH WEAK RIDGING TO ITS WEST
EXTENDING FROM THE CENTRAL PLAINS NORTHWARD INTO NORTHERN MANITOBA.
SEVERAL SHORTWAVES ARE EMBEDDED WITH THE MORE ZONAL PORTION OF THE
RIDGING OVER THE NORTHERN PLAINS AND UPPER MISSISSIPPI RIVER VALLEY.
THE MOST NOTABLE IS A VORT MAX OVER SOUTH DAKOTA WHICH IS PART OF A
TROUGH AXIS EXTENDING FROM SOUTHERN ALBERTA INTO NORTHERN NEBRASKA
WHICH IS PUSHING EASTWARD. THIS WILL LIKELY AFFECT THE LOCAL
FORECAST COMING UP TONIGHT/THURSDAY MORNING. TO THE WEST A CLOSED
UPPER LOW HAS STALLED OUT OVER THE WESTERN OREGON/CALIFORNIA BORDER.
AT THE SURFACE...AN OUTFLOW BOUNDARY FROM CONVECTION TO THE NORTH
HAD PUSHED DOWN LAKE MICHIGAN AND INTO NORTHEAST ILLINOIS THIS PAST
EVENING TURNING WINDS NORTHEASTERLY. THIS BOUNDARY HAS WASHED OUT
AS EVIDENCED BY SEVERAL SITES BEHIND WHERE IT PASSED HAVING SWITCHED
AROUND TO A SOUTHWEST WIND. THE COOL FRONT IS NOW JUST NORTH OF
FREEPORT AND JUST SOUTH OF MIDWAY AND IS STILL MOVING SOUTHWARD.
THE MOVEMENT OF THIS FRONT AND THE UPPER SHORT WAVES WILL BE THE
MAIN FEATURES OF NOTE FOR THE SHORT TERM.
TODAY...THE COOL FRONTAL POSITION WILL BE ONE OF THE MAIN CHALLENGES
THROUGH THE DAY AND WILL DICTATE THE TEMP AND PRECIP FORECASTS INTO
THIS EVENING. CURRENTLY...PRECIPITATION IS ASSOCIATED WITH THE MID
LEVEL BAROCLINIC ZONE TRAILING NORTH OF THE FRONT FROM THE TWIN
CITIES ACROSS CENTRAL LAKE MICHIGAN AND ARCHING SOUTHEASTWARD ACROSS
CENTRAL LOWER MICHIGAN. ACTIVITY WILL LIKELY FESTER ALONG THIS ZONE
PERIODICALLY THROUGH THE DAY WITH A SLOW SOUTHWARD MOVEMENT OF THE
MID LEVEL TEMP GRADIENT. AT THIS POINT EXPECT THIS TO BE FOCUSED TO
THE NORTH OF THE CWA. CANNOT COMPLETELY RULE OUT ISOLATED
DEVELOPMENT NEAR THE SURFACE FRONT THIS MORNING BUT CHANCES APPEAR
SLIM. LATEST NAM AND GFS PUT THE FRONT...IN A SOMEWHAT INCOHERENT
STATE...OVER THE FAR SOUTHWESTERN CWA BY EARLY AFTERNOON. LOCAL HIGH
RES GUIDANCE IS A LITTLE SLOWER WITH THE BOUNDARY AND THUS FURTHER
NORTH WITH IT FOR THE AFTERNOON. THE LATEST SURFACE ANALYSIS
SUGGESTS THAT THERE IS A WEAK LOW CENTER OVER NORTHEAST IOWA WHICH
THE RAP ALSO DEPICTS. THE RAP SOLUTION OF THE FRONT SLOWING AND
EVEN PUSHING BACK NORTHWARD SOMEWHAT AS THIS LOW CENTER MOVES
EASTWARD IS PLAUSIBLE. DESPITE THE UNCERTAINTY WITH THE FRONTAL
POSITION THROUGH THE DAY...THE BOUNDARY WILL MOVE INTO HIGHER
DEW POINT AIR ALLOWING FOR SOME POOLING OF MOISTURE AHEAD OF IT
THIS AFTERNOON WHICH IS EXPECTED TO RESULT IN STRONG SURFACE BASED
INSTABILITY ALONG AND SOUTH OF THE FRONT. WITH SOME MIXING
EXPECTED MIXED LAYER INSTABILITY WILL BE LOWER BUT STILL
SUFFICIENT TO SUPPORT STORMS. A SHARP INSTABILITY GRADIENT IS
EXPECTED TO SET UP WITH LATEST THINKING HAVING IT RUN FROM ROUGHLY
ROCKFORD DOWN TOWARDS JOLIET AND EASTWARD TOWARDS RENSSELAER
DURING THE AFTERNOON...WITH EXACT PLACEMENT DEPENDENT ON HOW FAR
SOUTH THE FRONT MOVES. BEYOND RATHER BROAD LOW LEVEL CONVERGENCE
ALONG THE FRONT THERE IS NOT MUCH IN THE WAY OF A LARGER SCALE
TRIGGERING MECHANISM BUT CONVECTIVE TEMPERATURES IN THE MID 90S
SHOULD BE ATTAINABLE SO ISOLATED TO SCATTERED DEVELOPMENT IS
PLAUSIBLE. STORMS THAT DO FORM WILL HAVE AT LEAST SOME SEVERE WIND
POTENTIAL GIVEN THE INVERTED V SOUNDING. EXPECT THAT THE BEST
CHANCE FOR OCCURRENCE IS FROM ROUGHLY ROCKFORD TO JOLIET TO
RENSSELAER SOUTHWARD IN LINE WITH THE EXPECTED INSTABILITY
GRADIENT. HOWEVER...THIS THREAT AREA MAY PUSH SOUTHWESTWARD IF THE
FRONT CAN KEEP SOME FORWARD SPEED THOUGH LATE AFTERNOON. TEMPS ARE
THE NEXT ISSUE...AS INDICATED ABOVE HUMIDITY WILL BE HIGHER THAN
TUESDAY AHEAD OF THE FRONT THANKS TO MOISTURE POOLING. WITH HIGHS
STILL EXPECTED TO BE IN THE MID TO EVEN UPPER 90S SOUTH WILL
MAINTAIN THE HEAT ADVISORY...BUT SOME OF THE NORTHERN PORTIONS OF
IT MAY NOT REACH CRITERIA IF THE FRONT REMAINS ON THE MOVE...OF
CONCERN WOULD BE JASPER AND NEWTON COUNTIES. WILL KEEP THE
ADVISORY GOING AS IS AND LET THE DAY SHIFT MONITOR TEMPS AND TRIM
IF NEEDED. HIGHS NORTH OF THE FRONT WILL BE TRICKIER...BUT BE
RELATIVELY COOLER WITH HIGHS IN THE UPPER 80S TO AROUND
90...THOUGH A NORTHEASTERLY WIND OFF THE LAKE WILL PROBABLY KEEP
LAKESHORE AREAS IN THE MID 80S. DO SEE SOME BUST POTENTIAL ACROSS
THESE AREAS WITH SOME CONCERN THAT FORECAST HIGHS MAY BE A BIT
WARM. IT WILL STILL BE HUMID IN THESE AREAS AS WELL BUT BELOW
ADVISORY LEVELS.
TONIGHT AND THURSDAY...LARGER SCALE FORCING INCREASES TONIGHT...MOST
NOTABLY LATE...AS THE MID LEVEL BAROCLINIC ZONE CURRENTLY NORTH OF THE
AREA RE-ORIENTS FROM WEST TO EAST TO NORTHWEST TO SOUTHEAST AND
SETTLES INTO THE AREA. IN ADDITION...THE WAVE NOTED OVER SOUTH
DAKOTA AND ITS ASSOCIATED TROUGH AXIS IS EXPECTED TO REACH THE AREA
AS IT TURNS SOUTHEASTWARD WITH THE UPPER FLOW BUCKLING AS THE LARGE
QUEBEC UPPER LOW MOVES SOUTHWARD. THE WAVE WILL CROSS THE AREA LATE
TONIGHT INTO THURSDAY MORNING AND WILL A HAVE DECENT CHANCE OF
BRINGING CONVECTION ACROSS THE ENTIRE FORECAST AREA. ITS NOT CLEAR
HOW WIDESPREAD COVERAGE WILL BE HOWEVER BUT THIS CHANCE FOR PRECIP
IS DECENT. LOW CHANCES FOR SCATTERED ACTIVITY WILL BE IN PLACE THIS
EVENING ACROSS THE SOUTHWESTERN CWA WITH LITTLE SUPPORT FOR POPS
NORTHEAST DURING THAT TIME...THOUGH THE BAROCLINIC ZONE MAY BE
GENERATING SOME ACTIVITY JUST TO THE NORTHEAST. PRECIP CHANCES WIND
DOWN THURSDAY AFTERNOON...THOUGH LOW CHANCES CONTINUE SOUTH PERHAPS
THROUGH EARLY EVENING BEFORE THE UPPER FORCING EXITS TO THE
SOUTHEAST AND SURFACE HIGH PRESSURE ARRIVES FROM THE NORTH. HIGHS
THURSDAY WILL RANGE FROM THE MID 80S NORTHEAST WITH FLOW OFF THE
LAKE TO AROUND 90 SOUTHWEST...THOUGH TEMPS MAY NOT REACH THESE
LEVELS TIL LATER IN THE AFTERNOON IF PRECIP IS IN PLACE IN THE
MORNING.
FRIDAY THROUGH TUESDAY...SURFACE HIGH PRESSURE WILL BE IN PLACE
FRIDAY WITH THE MAIN UPPER TROUGH ALONG THE EAST COAST AND A BIG
RIDGE OVER THE WESTERN AND CENTRAL U.S...WITH A RIDGE AXIS EXTENDING
NORTHEAST TOWARDS HUDSON BAY AND ANOTHER AIMED NORTHWEST INTO
ALBERTA...WITH A TROUGH PASSING BETWEEN THE TWO OVER NORTHERN
MANITOBA. THIS TROUGH FLATTENS THE EASTERN RIDGE AXIS WHILE A BIG
UPPER LOW ARRIVES OVER WESTERN BRITISH COLUMBIA TO AMPLIFY THE
WESTERN AXIS...THOUGH THERE IS A WEAK TROUGH AHEAD OF IT TO
TEMPORARILY BREAK IT DOWN. THIS RESULTS IN A NORTHWESTERLY FLOW FROM
THE NORTHERN PLAINS INTO THE LOWER GREAT LAKES BY SUNDAY. THE
QUESTION IS HOW FAR SOUTH THIS ACTIVE CORRIDOR OF FLOW WILL BE
PLACED. THE GFS KEEPS THE LOCAL AREA IN THE PATH OF WEAK SHORTWAVES
WHILE THE ECMWF...WHICH IS VERY SIMILAR IN THE OVERALL
PATTERN...KEEPS THE WAVE TRAIN A LITTLE FURTHER NORTHEAST OF HERE
INTO EARLY NEXT WEEK. FRIDAY LOOKS LIKE A RELATIVELY PLEASANT DAY
WITH SURFACE HIGH PRESSURE KEEPING A NORTHEAST WIND IN PLACE AND A
CORRIDOR OF COOLER MID LEVEL AIR...H85 TEMPS AROUND 14C...IN PLACE
BEHIND THE DEPARTING UPPER TROUGH. THIS SHOULD LEAD TO HIGHS IN THE
MID TO UPPER 80S...THOUGH SOME WESTERN AREAS COULD AGAIN TOUCH 90.
SATURDAY STILL LOOKS TO BE DRY BUT THE ABOVE BECOMES MORE OF AN
ISSUE FROM SUNDAY AND BEYOND. POP CHANCES WOULD LIKELY BE LOW
ANYWAYS GIVEN THE NATURE OF THESE EMBEDDED IMPULSES SO WILL
GENERALLY KEEP THE FORECAST DRY FOR NOW. TEMPS WILL BEGIN TO WARM
AGAIN SATURDAY AND SUNDAY...WITH SOME POTENTIAL FOR A BIGGER WARM UP
EARLY NEXT WEEK WITH THE GFS AND ECMWF PAINTING LOW 20S H85 TEMPS AT
VARIOUS TIMES. OVERALL FORECAST CONFIDENCE IN PRECIP POTENTIAL IS
LOW AND LITTLE BIT HIGHER IN TERMS OF A WARMING TREND CONTINUING
INTO EARLY NEXT WEEK.
MDB
&&
.CLIMATE...
305 PM CDT...
RECORDS FOR TODAY JULY 17TH ARE AS FOLLOWS:
CHICAGO RECORD HIGH: 100 /1942/
ROCKFORD RECORD HIGH: 104 /1936/
CHICAGO RECORD WARM LOW: 80 /1878/
ROCKFORD RECORD WARM LOW: 76 /1982/
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
TIMING OF ARRIVAL COLD FRONTAL PASSAGE ACROSS TERMINALS.
POTENTIAL FOR CONVECTIVE ACTIVITY ALONG AND AHEAD OF COLD FRONT
TODAY AS WELL AS ELEVATED CONVECTION POST FRONTAL DURING THE
OVERNIGHT.
TRS
//DISCUSSION...UPDATED 06Z...
KLOT...TORD AND TMDW RADARS SHOWED THE OUTFLOW BOUNDARY THAT
ORIGINATED FROM THUNDERSTORMS OVER E CENTRAL WI AND CENTRAL LAKE
MI CONTINUED TO DROP S DURING THE EVENING FROM NORTHEASTERN TO
SOUTHEASTERN COOK CO. BURNHAM HARBOR AND MDW BRIEFLY SHOWING
LIGHT N-NNE WINDS 04-05Z BUT HAVE ALREADY SWITCHED BACK TO A
LIGHT SW FLOW.
COLD FRONT AT 05Z WAS LOCATED E-W ACROSS SOUTHERN LOWER MI AND
SOUTHERN LAKE MI TO FAR SOUTHEASTERN WI THEN CURVED WNW TO
SOUTHERN MN. MAIN AREA OF CONVECTION WAS FROM E CENTRAL WI ESE
ACROSS LAKE MI TO W CENTRAL LOWER MI. THIS WAS POST FRONTAL WHERE
ELEVATED CAPE STILL IN PLACE AS A SHORT WAVE MOVED ESE FROM MN
ACROSS CENTRAL WI DURING TUE AFTERNOON AND EVENING.
LATEST MODEL RUNS HAVE THE COLD FRONT SINKING S ACROSS THE STATE
LINE DURING THE OVERNIGHT AND EARLY MORNING...AND PUSHING ACROSS
THE CHI AREA TERMINALS AROUND 13Z. WITH ONLY A HOUR OR TWO OF
HEATING BEFORE THE ARRIVAL AND A LACK OF MID OR UPPER LEVEL
SUPPORT TO NOT SEE ANY SIGNIFICANT POTENTIAL FOR CONVECTIVE
DEVELOPMENT BEFORE THE FRONT PASSES BY THE TERMINALS.
UPSTREAM...A FEW SHORT NARROW LINE SEGMENTS OF SHOWERS AND
THUNDERSTORMS WERE OCCURRING FROM W CENTRAL WI ACROSS CENTRAL MN
TO NW SD. THE SE WERE OCCURRING ALONG THE LEADING EDGE OF THE
TIGHT 850HPA THERMAL GRADIENT. THIS THERMAL GRADIENT DOES MIGRATE
SOUTHWARD TODAY BUT MODELS SHOW IT TO MOVING INTO FAR NE IL TIL
THIS AFTERNOON. CANNOT TOTALLY RULE OUT AN ISOLATED OR WIDELY
SCATTERED THUNDERSTORMS ASSOCIATED WITH THIS BAROCLINIC ZONE
DURING THE AFTERNOON AT OR IN THE VC OF THE CHI TERMINALS BUT
LOCATIONS ALONG THE COLD FRONT LOOK TO BE BETTER CANDIDATES FOR
SEEING SIGNIFICANT CONVECTION LATER TODAY WHERE LOW LEVEL DEW
POINT POOLING AND CONVERGENCE MAXIMIZE CAPE VALUES FROM SE TO S
TO SW AND W OF THE CHI AREA.
FURTHER UP STEAM...MORE SHOWERS AND THUNDERSTORMS WERE OCCURRING
IN CENTRAL SD AS A MORE WELL DEFINED SHORT WAVE TROUGH WAS MOVING
E FROM WESTERN SD AND NEB. THE SHORT WAVE TROUGH AXIS IS PROGGED
TO REACH W CENTRAL WI...SE MN AND EASTERN IA BY 00Z AND TO DROP
ESE ACROSS SOUTHERN WI AS WELL AND NORTHERN AND W CENTRAL
OVERNIGHT. THIS WILL BRING A CHANCE OF SHOWERS AND THUNDERSHOWERS
TO THE LOCAL TERMINALS DURING THE LATE NIGHT AND EARLY MORNING
HOURS OF THU.
WITH THE COLD FRONT SLIPPING S OF THE TERMINALS DURING THE FIRST
PART OF TODAY AND THE SOUTHERN PORTION OF A LARGE RIDGE OF HIGH
PRESSURE BUILDING SE OVER THE UPPER GREAT LAKES LOCAL WINDS
EXPECTED TO BE OUT OF THE NE THOUGH GENERALLY AOB 10KT AS
GRADIENT BEHIND THE FRONT IS SHOWN TO BE PRETTY WEAK.
TRS
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
HIGH CONFIDENCE IN FORECAST WIND TRENDS.
MODERATE CONFIDENCE IS CONVECTIVE ACTIVITY TO NOT AFFECT
IMMEDIATE CHI VC TODAY.
TRS
//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...
THURSDAY...CHC TSRA...ELSE VFR.
FRIDAY...VFR.
SATURDAY...VFR.
SUNDAY...VFR.
MONDAY...CHC TSRA...ELSE VFR.
BMD
&&
.MARINE...
432 AM CDT
A COLD FRONT TRAILS FROM LOW PRESSURE OVER THE GULF OF ST.
LAWRENCE ACROSS SOUTHERN LOWER MI...FAR SOUTHERN LAKE MI AND FAR
NORTHERN IL EARLY THIS MORNING. THE COLD FRONT WILL CONTINUE TO
MOVE SLOWLY SOUTHWARD TODAY AND TONIGHT...EXTENDING FROM CENTRAL
IN ACROSS IL TO CENTRAL IA BY THURSDAY MORNING. HIGH PRESSURE OF
WILL BUILD SE FROM HUDSON BAY AND ONTARIO BEHIND THE COLD
FRONT...SPREADING ACROSS THE GREAT LAKES TODAY AND TONIGHT. LOW
PRESSURE WILL RIDE ALONG THE FRONTAL BOUNDARY FROM IA TO THE
UPPER OH VALLEY DURING THU WHILE A RIDGE OF HIGH PRESSURE REMAINS
OVER THE GREAT LAKES. LOW PRESSURE WILL BE TRACKING E FROM CENTRAL
CANADA TO HUDSON BAY THU NIGHT THROUGH FRI NIGHT WHILE THE RIDGE
OVER THE GREAT LAKES SHIFTS S OVER THE NORTHEASTERN U.S. AND THE
MIDWEST. THE COLD FRONT TRAILING FROM THE CANADIAN LOW WILL DROP S
ACROSS NORTHERN LAKE MI SUN NIGHT.
TRS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...HEAT ADVISORY...ILZ019-ILZ021-ILZ023-ILZ032-ILZ033-ILZ039 UNTIL
7 PM WEDNESDAY.
IN...HEAT ADVISORY...INZ010-INZ011-INZ019 UNTIL 7 PM WEDNESDAY.
LM...NONE.
&&
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
323 AM CDT WED JUL 18 2012
.DISCUSSION...
322 AM CDT
HEAT AND THUNDER CHANCES REMAIN THE MAIN FORECAST CHALLENGES THIS
MORNING. EARLY MORNING WATER VAPOR IMAGERY SHOWS A LARGE CLOSED
UPPER LOW OVER NORTHERN QUEBEC WITH WEAK RIDGING TO ITS WEST
EXTENDING FROM THE CENTRAL PLAINS NORTHWARD INTO NORTHERN MANITOBA.
SEVERAL SHORTWAVES ARE EMBEDDED WITH THE MORE ZONAL PORTION OF THE
RIDGING OVER THE NORTHERN PLAINS AND UPPER MISSISSIPPI RIVER VALLEY.
THE MOST NOTABLE IS A VORT MAX OVER SOUTH DAKOTA WHICH IS PART OF A
TROUGH AXIS EXTENDING FROM SOUTHERN ALBERTA INTO NORTHERN NEBRASKA
WHICH IS PUSHING EASTWARD. THIS WILL LIKELY AFFECT THE LOCAL
FORECAST COMING UP TONIGHT/THURSDAY MORNING. TO THE WEST A CLOSED
UPPER LOW HAS STALLED OUT OVER THE WESTERN OREGON/CALIFORNIA BORDER.
AT THE SURFACE...AN OUTFLOW BOUNDARY FROM CONVECTION TO THE NORTH
HAD PUSHED DOWN LAKE MICHIGAN AND INTO NORTHEAST ILLINOIS THIS PAST
EVENING TURNING WINDS NORTHEASTERLY. THIS BOUNDARY HAS WASHED OUT
AS EVIDENCED BY SEVERAL SITES BEHIND WHERE IT PASSED HAVING SWITCHED
AROUND TO A SOUTHWEST WIND. THE COOL FRONT IS NOW JUST NORTH OF
FREEPORT AND JUST SOUTH OF MIDWAY AND IS STILL MOVING SOUTHWARD.
THE MOVEMENT OF THIS FRONT AND THE UPPER SHORT WAVES WILL BE THE
MAIN FEATURES OF NOTE FOR THE SHORT TERM.
TODAY...THE COOL FRONTAL POSITION WILL BE ONE OF THE MAIN CHALLENGES
THROUGH THE DAY AND WILL DICTATE THE TEMP AND PRECIP FORECASTS INTO
THIS EVENING. CURRENTLY...PRECIPITATION IS ASSOCIATED WITH THE MID
LEVEL BAROCLINIC ZONE TRAILING NORTH OF THE FRONT FROM THE TWIN
CITIES ACROSS CENTRAL LAKE MICHIGAN AND ARCHING SOUTHEASTWARD ACROSS
CENTRAL LOWER MICHIGAN. ACTIVITY WILL LIKELY FESTER ALONG THIS ZONE
PERIODICALLY THROUGH THE DAY WITH A SLOW SOUTHWARD MOVEMENT OF THE
MID LEVEL TEMP GRADIENT. AT THIS POINT EXPECT THIS TO BE FOCUSED TO
THE NORTH OF THE CWA. CANNOT COMPLETELY RULE OUT ISOLATED
DEVELOPMENT NEAR THE SURFACE FRONT THIS MORNING BUT CHANCES APPEAR
SLIM. LATEST NAM AND GFS PUT THE FRONT...IN A SOMEWHAT INCOHERENT
STATE...OVER THE FAR SOUTHWESTERN CWA BY EARLY AFTERNOON. LOCAL HIGH
RES GUIDANCE IS A LITTLE SLOWER WITH THE BOUNDARY AND THUS FURTHER
NORTH WITH IT FOR THE AFTERNOON. THE LATEST SURFACE ANALYSIS
SUGGESTS THAT THERE IS A WEAK LOW CENTER OVER NORTHEAST IOWA WHICH
THE RAP ALSO DEPICTS. THE RAP SOLUTION OF THE FRONT SLOWING AND
EVEN PUSHING BACK NORTHWARD SOMEWHAT AS THIS LOW CENTER MOVES
EASTWARD IS PLAUSIBLE. DESPITE THE UNCERTAINTY WITH THE FRONTAL
POSITION THROUGH THE DAY...THE BOUNDARY WILL MOVE INTO HIGHER
DEWPOINT AIR ALLOWING FOR SOME POOLING OF MOISTURE AHEAD OF IT
THIS AFTERNOON WHICH IS EXPECTED TO RESULT IN STRONG SURFACE BASED
INSTABILITY ALONG AND SOUTH OF THE FRONT. WITH SOME MIXING
EXPECTED MIXED LAYER INSTABILITY WILL BE LOWER BUT STILL
SUFFICIENT TO SUPPORT STORMS. A SHARP INSTABILITY GRADIENT IS
EXPECTED TO SET UP WITH LATEST THINKING HAVING IT RUN FROM ROUGHLY
ROCKFORD DOWN TOWARDS JOLIET AND EASTWARD TOWARDS RENSSELAER
DURING THE AFTERNOON...WITH EXACT PLACEMENT DEPENDENT ON HOW FAR
SOUTH THE FRONT MOVES. BEYOND RATHER BROAD LOW LEVEL CONVERGENCE
ALONG THE FRONT THERE IS NOT MUCH IN THE WAY OF A LARGER SCALE
TRIGGERING MECHANISM BUT CONVECTIVE TEMPERATURES IN THE MID 90S
SHOULD BE ATTAINABLE SO ISOLATED TO SCATTERED DEVELOPMENT IS
PLAUSIBLE. STORMS THAT DO FORM WILL HAVE AT LEAST SOME SEVERE WIND
POTENTIAL GIVEN THE INVERTED V SOUNDING. EXPECT THAT THE BEST
CHANCE FOR OCCURRENCE IS FROM ROUGHLY ROCKFORD TO JOLIET TO
RENSSELAER SOUTHWARD IN LINE WITH THE EXPECTED INSTABILITY
GRADIENT. HOWEVER...THIS THREAT AREA MAY PUSH SOUTHWESTWARD IF THE
FRONT CAN KEEP SOME FORWARD SPEED THOUGH LATE AFTERNOON. TEMPS ARE
THE NEXT ISSUE...AS INDICATED ABOVE HUMIDITY WILL BE HIGHER THAN
TUESDAY AHEAD OF THE FRONT THANKS TO MOISTURE POOLING. WITH HIGHS
STILL EXPECTED TO BE IN THE MID TO EVEN UPPER 90S SOUTH WILL
MAINTAIN THE HEAT ADVISORY...BUT SOME OF THE NORTHERN PORTIONS OF
IT MAY NOT REACH CRITERIA IF THE FRONT REMAINS ON THE MOVE...OF
CONCERN WOULD BE JASPER AND NEWTON COUNTIES. WILL KEEP THE
ADVISORY GOING AS IS AND LET THE DAY SHIFT MONITOR TEMPS AND TRIM
IF NEEDED. HIGHS NORTH OF THE FRONT WILL BE TRICKIER...BUT BE
RELATIVELY COOLER WITH HIGHS IN THE UPPER 80S TO AROUND
90...THOUGH A NORTHEASTERLY WIND OFF THE LAKE WILL PROBABLY KEEP
LAKESHORE AREAS IN THE MID 80S. DO SEE SOME BUST POTENTIAL ACROSS
THESE AREAS WITH SOME CONCERN THAT FORECAST HIGHS MAY BE A BIT
WARM. IT WILL STILL BE HUMID IN THESE AREAS AS WELL BUT BELOW
ADVISORY LEVELS.
TONIGHT AND THURSDAY...LARGER SCALE FORCING INCREASES TONIGHT...MOST
NOTABLY LATE...AS THE MID LEVEL BAROCLINIC ZONE CURRENTLY NORTH OF THE
AREA RE-ORIENTS FROM WEST TO EAST TO NORTHWEST TO SOUTHEAST AND
SETTLES INTO THE AREA. IN ADDITION...THE WAVE NOTED OVER SOUTH
DAKOTA AND ITS ASSOCIATED TROUGH AXIS IS EXPECTED TO REACH THE AREA
AS IT TURNS SOUTHEASTWARD WITH THE UPPER FLOW BUCKLING AS THE LARGE
QUEBEC UPPER LOW MOVES SOUTHWARD. THE WAVE WILL CROSS THE AREA LATE
TONIGHT INTO THURSDAY MORNING AND WILL A HAVE DECENT CHANCE OF
BRINGING CONVECTION ACROSS THE ENTIRE FORECAST AREA. ITS NOT CLEAR
HOW WIDESPREAD COVERAGE WILL BE HOWEVER BUT THIS CHANCE FOR PRECIP
IS DECENT. LOW CHANCES FOR SCATTERED ACTIVITY WILL BE IN PLACE THIS
EVENING ACROSS THE SOUTHWESTERN CWA WITH LITTLE SUPPORT FOR POPS
NORTHEAST DURING THAT TIME...THOUGH THE BAROCLINIC ZONE MAY BE
GENERATING SOME ACTIVITY JUST TO THE NORTHEAST. PRECIP CHANCES WIND
DOWN THURSDAY AFTERNOON...THOUGH LOW CHANCES CONTINUE SOUTH PERHAPS
THROUGH EARLY EVENING BEFORE THE UPPER FORCING EXITS TO THE
SOUTHEAST AND SURFACE HIGH PRESSURE ARRIVES FROM THE NORTH. HIGHS
THURSDAY WILL RANGE FROM THE MID 80S NORTHEAST WITH FLOW OFF THE
LAKE TO AROUND 90 SOUTHWEST...THOUGH TEMPS MAY NOT REACH THESE
LEVELS TIL LATER IN THE AFTERNOON IF PRECIP IS IN PLACE IN THE
MORNING.
FRIDAY THROUGH TUESDAY...SURFACE HIGH PRESSURE WILL BE IN PLACE
FRIDAY WITH THE MAIN UPPER TROUGH ALONG THE EAST COAST AND A BIG
RIDGE OVER THE WESTERN AND CENTRAL U.S...WITH A RIDGE AXIS EXTENDING
NORTHEAST TOWARDS HUDSON BAY AND ANOTHER AIMED NORTHWEST INTO
ALBERTA...WITH A TROUGH PASSING BETWEEN THE TWO OVER NORTHERN
MANITOBA. THIS TROUGH FLATTENS THE EASTERN RIDGE AXIS WHILE A BIG
UPPER LOW ARRIVES OVER WESTERN BRITISH COLUMBIA TO AMPLIFY THE
WESTERN AXIS...THOUGH THERE IS A WEAK TROUGH AHEAD OF IT TO
TEMPORARILY BREAK IT DOWN. THIS RESULTS IN A NORTHWESTERLY FLOW FROM
THE NORTHERN PLAINS INTO THE LOWER GREAT LAKES BY SUNDAY. THE
QUESTION IS HOW FAR SOUTH THIS ACTIVE CORRIDOR OF FLOW WILL BE
PLACED. THE GFS KEEPS THE LOCAL AREA IN THE PATH OF WEAK SHORTWAVES
WHILE THE ECMWF...WHICH IS VERY SIMILAR IN THE OVERALL
PATTERN...KEEPS THE WAVE TRAIN A LITTLE FURTHER NORTHEAST OF HERE
INTO EARLY NEXT WEEK. FRIDAY LOOKS LIKE A RELATIVELY PLEASANT DAY
WITH SURFACE HIGH PRESSURE KEEPING A NORTHEAST WIND IN PLACE AND A
CORRIDOR OF COOLER MID LEVEL AIR...H85 TEMPS AROUND 14C...IN PLACE
BEHIND THE DEPARTING UPPER TROUGH. THIS SHOULD LEAD TO HIGHS IN THE
MID TO UPPER 80S...THOUGH SOME WESTERN AREAS COULD AGAIN TOUCH 90.
SATURDAY STILL LOOKS TO BE DRY BUT THE ABOVE BECOMES MORE OF AN
ISSUE FROM SUNDAY AND BEYOND. POP CHANCES WOULD LIKELY BE LOW
ANYWAYS GIVEN THE NATURE OF THESE EMBEDDED IMPULSES SO WILL
GENERALLY KEEP THE FORECAST DRY FOR NOW. TEMPS WILL BEGIN TO WARM
AGAIN SATURDAY AND SUNDAY...WITH SOME POTENTIAL FOR A BIGGER WARM UP
EARLY NEXT WEEK WITH THE GFS AND ECMWF PAINTING LOW 20S H85 TEMPS AT
VARIOUS TIMES. OVERALL FORECAST CONFIDENCE IN PRECIP POTENTIAL IS
LOW AND LITTLE BIT HIGHER IN TERMS OF A WARMING TREND CONTINUING
INTO EARLY NEXT WEEK.
MDB
&&
.CLIMATE...
305 PM CDT...
RECORDS FOR TODAY JULY 17TH ARE AS FOLLOWS:
CHICAGO RECORD HIGH: 100 /1942/
ROCKFORD RECORD HIGH: 104 /1936/
CHICAGO RECORD WARM LOW: 80 /1878/
ROCKFORD RECORD WARM LOW: 76 /1982/
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
TIMING OF ARRIVAL COLD FRONTAL PASSAGE ACROSS TERMINALS.
POTENTIAL FOR CONVECTIVE ACTIVITY ALONG AND AHEAD OF COLD FRONT
TODAY AS WELL AS ELEVATED CONVECTION POST FRONTAL DURING THE
OVERNIGHT.
TRS
//DISCUSSION...UPDATED 06Z...
KLOT...TORD AND TMDW RADARS SHOWED THE OUTFLOW BOUNDARY THAT
ORIGINATED FROM THUNDERSTORMS OVER E CENTRAL WI AND CENTRAL LAKE
MI CONTINUED TO DROP S DURING THE EVENING FROM NORTHEASTERN TO
SOUTHEASTERN COOK CO. BURNHAM HARBOR AND MDW BRIEFLY SHOWING
LIGHT N-NNE WINDS 04-05Z BUT HAVE ALREADY SWITCHED BACK TO A
LIGHT SW FLOW.
COLD FRONT AT 05Z WAS LOCATED E-W ACROSS SOUTHERN LOWER MI AND
SOUTHERN LAKE MI TO FAR SOUTHEASTERN WI THEN CURVED WNW TO
SOUTHERN MN. MAIN AREA OF CONVECTION WAS FROM E CENTRAL WI ESE
ACROSS LAKE MI TO W CENTRAL LOWER MI. THIS WAS POST FRONTAL WHERE
ELEVATED CAPE STILL IN PLACE AS A SHORT WAVE MOVED ESE FROM MN
ACROSS CENTRAL WI DURING TUE AFTERNOON AND EVENING.
LATEST MODEL RUNS HAVE THE COLD FRONT SINKING S ACROSS THE STATE
LINE DURING THE OVERNIGHT AND EARLY MORNING...AND PUSHING ACROSS
THE CHI AREA TERMINALS AROUND 13Z. WITH ONLY A HOUR OR TWO OF
HEATING BEFORE THE ARRIVAL AND A LACK OF MID OR UPPER LEVEL
SUPPORT TO NOT SEE ANY SIGNIFICANT POTENTIAL FOR CONVECTIVE
DEVELOPMENT BEFORE THE FRONT PASSES BY THE TERMINALS.
UPSTREAM...A FEW SHORT NARROW LINE SEGMENTS OF SHOWERS AND
THUNDERSTORMS WERE OCCURRING FROM W CENTRAL WI ACROSS CENTRAL MN
TO NW SD. THE SE WERE OCCURRING ALONG THE LEADING EDGE OF THE
TIGHT 850HPA THERMAL GRADIENT. THIS THERMAL GRADIENT DOES MIGRATE
SOUTHWARD TODAY BUT MODELS SHOW IT TO MOVING INTO FAR NE IL TIL
THIS AFTERNOON. CANNOT TOTALLY RULE OUT AN ISOLATED OR WIDELY
SCATTERED THUNDERSTORMS ASSOCIATED WITH THIS BAROCLINIC ZONE
DURING THE AFTERNOON AT OR IN THE VC OF THE CHI TERMINALS BUT
LOCATIONS ALONG THE COLD FRONT LOOK TO BE BETTER CANDIDATES FOR
SEEING SIGNIFICANT CONVECTION LATER TODAY WHERE LOW LEVEL DEW
POINT POOLING AND CONVERGENCE MAXIMIZE CAPE VALUES FROM SE TO S
TO SW AND W OF THE CHI AREA.
FURTHER UP STEAM...MORE SHOWERS AND THUNDERSTORMS WERE OCCURRING
IN CENTRAL SD AS A MORE WELL DEFINED SHORT WAVE TROUGH WAS MOVING
E FROM WESTERN SD AND NEB. THE SHORT WAVE TROUGH AXIS IS PROGGED
TO REACH W CENTRAL WI...SE MN AND EASTERN IA BY 00Z AND TO DROP
ESE ACROSS SOUTHERN WI AS WELL AND NORTHERN AND W CENTRAL
OVERNIGHT. THIS WILL BRING A CHANCE OF SHOWERS AND THUNDERSHOWERS
TO THE LOCAL TERMINALS DURING THE LATE NIGHT AND EARLY MORNING
HOURS OF THU.
WITH THE COLD FRONT SLIPPING S OF THE TERMINALS DURING THE FIRST
PART OF TODAY AND THE SOUTHERN PORTION OF A LARGE RIDGE OF HIGH
PRESSURE BUILDING SE OVER THE UPPER GREAT LAKES LOCAL WINDS
EXPECTED TO BE OUT OF THE NE THOUGH GENERALLY AOB 10KT AS
GRADIENT BEHIND THE FRONT IS SHOWN TO BE PRETTY WEAK.
TRS
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
HIGH CONFIDENCE IN FORECAST WIND TRENDS.
MODERATE CONFIDENCE IS CONVECTIVE ACTIVITY TO NOT AFFECT
IMMEDIATE CHI VC TODAY.
TRS
//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...
THURSDAY...CHC TSRA...ELSE VFR.
FRIDAY...VFR.
SATURDAY...VFR.
SUNDAY...VFR.
MONDAY...CHC TSRA...ELSE VFR.
BMD
&&
.MARINE...
354 PM CDT
THE PRIMARY MARINE CONCERN IS FOR RELATIVELY STRONG NORTH AND
NORTHEAST WINDS OVER THE LAKE AFTER A COOL FRONT PUSHES SOUTH OF
THE LAKE TONIGHT. WITH A MARGINALLY COOLER AIR MASS MOVING OVER
THE VERY WARM LAKE WATERS...COULD SEE SOME GUSTS IN THE 20 TO 25
KT RANGE FROM LATE TONIGHT THROUGH WEDNESDAY NIGHT...ESPECIALLY
FOR THE CENTRAL AND SOUTHERN PORTION OF THE LAKE. THIS WILL ALLOW
FOR WAVES TO BUILD TO THE 3 TO 7 FT RANGE WHERE THE STRONGEST
WINDS OCCUR. HIGH PRESSURE BUILDING OVER THE LAKES REGION THURSDAY
WILL BRING ANOTHER DAY OF MODEST...UP TO 20 KT EAST TO NORTHEAST
FLOW. THEN PRIMARILY LIGHTER WINDS CAN BE EXPECTED FRIDAY AND
SATURDAY WITH THE HIGH OVERHEAD. LATER SATURDAY AND SUNDAY...THE
HIGH PRESSURE WILL SLIDE EAST...BRINGING SOUTH AND SOUTHWEST
WINDS.
RC
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...HEAT ADVISORY...ILZ019-ILZ021-ILZ023-ILZ032-ILZ033-ILZ039 UNTIL
7 PM WEDNESDAY.
IN...HEAT ADVISORY...INZ010-INZ011-INZ019 UNTIL 7 PM WEDNESDAY.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WICHITA KS
842 PM CDT THU JUL 19 2012
.UPDATE...
TONIGHT:
WITH TSRA HAVING CALLED IT QUITS OVER SC KS HAVE UPDATED FORECAST TO
REMOVE "EVENING" TSRA DESCRIPTOR FROM THESE AREAS. HAZARDOUS WEATHER
OUTLOOK WILL BE UPDATED VERY SOON.
&&
.PREV DISCUSSION... /ISSUED 642 PM CDT THU JUL 19 2012/
AVIATION...00Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
THE NUMEROUS TSRA THAT HAD BEEN OCCURRING ACROSS SRN KS HAVE VENTURED
S OVER EXTREME NRN OK....HOWEVER A FEW ISOLD TSRA HAVE POPPED UP OVER
SC KS ~35NM NE OF KICT & WITH THESE CELLS MOVG S ~10KTS HAVE ASSIGNED
"VCTS" TO KICT TIL 02Z. ALL 5 TERMINALS TO MAINTAIN VFR STATUS UNTIL
FURTHER NOTICE AS MASSIVE...VERY STRONG UPR-DECK HIGH PRESSURE COVERS
NEARLY ALL OF U.S.
PREV DISCUSSION... /ISSUED 348 PM CDT THU JUL 19 2012/
DISCUSSION...
ISOLATED SHOWERS AND THUNDERSTORMS WITH A THREAT FOR WIND GUSTS TO
55 MPH MAY LINGER THROUGH THE EARLY EVENING HOURS BEFORE DRIFTING
SOUTH/DIMINISHING IN THE ABSENCE OF HEATING.
A MORE SUBSIDENT REGIME IS ANTICIPATED OVER THE WEEKEND AS THE H5
RIDGE EXPANDS ACROSS THE CENTRAL PLAINS. THE H85-H7 THERMAL
RIDGE/INCREASE IN THICKNESS CONTINUES TO SUPPORT RISING TEMPERATURES
WITH VALUES IN THE 105-109 DEGREE RANGE ANTICIPATED. DEEP VERTICAL
MIXING WILL ALLOW DEWPOINT TEMPERATURES TO PLUMMET DURING THE
AFTERNOON HOURS BUT HEAT INDICES WILL STILL MANAGE TO CLIMB TO
AROUND 105+ DEGREES AT TIMES. THEREFORE THE HEAT ADVISORY WILL BE
EXPANDED THROUGH TUESDAY.
WED-THU...ALTHOUGH TEMPERATURES ARE EXPECTED TO REMAIN WELL ABOVE
NORMAL/POSSIBLY LINGERING IN THE 100-105 DEGREE RANGE THERE MAY BE A
TEMPORARY BREAK DOWN OF THE MID/UPPER RIDGE TOWARD THE MIDDLE OF THE
WEEK AS A ROBUST MID/UPPER TROUGH TRANSLATES EAST ALONG THE
US/CANADIAN BORDER. IF THE RIDGE DOES TEMPORARILY BREAK DOWN IT MAY
BE FAIRLY SHORT-LIVED SO ONLY A SUBTLE TREND DOWN IN TEMPERATURES
WAS INTRODUCED ON THU.
AVIATION...18Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
TOUGH CONVECTIVE FORECAST. STORMS HAVE LINGERED ALONG A COUPLE OF
WEAK BOUNDARIES AND OUTFLOW FROM EARLIER STORMS. LATEST RUC
SEEMS HAVE BETTER HANDLE ON THE CURRENT OBSERVATIONS AND VERY SHORT
TERM TRENDS THAN OTHER GUIDANCE. THIS KEEPS BOUNDARY NORTH OF
KICT/KCNU THROUGH AT LEAST EARLY EVENING AND THEN WILL BLEND INTO
NAM AS BOUNDARY SAGS SOUTH DURING THE NIGHT. OF NOTE RUC SHUTS
DOWN MOST OF THE PRECIPITATION BY 2100 UTC. -HOWERTON
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 75 106 75 105 / 20 10 10 0
HUTCHINSON 76 105 75 103 / 20 10 10 0
NEWTON 78 104 78 103 / 20 10 10 0
ELDORADO 76 104 76 102 / 20 10 0 0
WINFIELD-KWLD 78 107 78 105 / 30 10 10 0
RUSSELL 71 105 71 107 / 10 0 10 0
GREAT BEND 73 105 72 106 / 10 10 10 0
SALINA 74 105 74 105 / 10 10 10 0
MCPHERSON 72 104 73 104 / 20 10 10 0
COFFEYVILLE 78 104 78 103 / 30 10 10 10
CHANUTE 77 101 76 100 / 20 10 10 10
IOLA 75 100 76 101 / 20 10 10 10
PARSONS-KPPF 77 102 77 102 / 30 10 10 10
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY UNTIL 7 PM CDT TUESDAY FOR KSZ032-033-047>053-
067>072-082-083-091>096-098>100.
&&
$$
AREA FORECAST DISCUSSION
NWS WICHITA KS
642 PM CDT THU JUL 19 2012
.AVIATION...00Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
THE NUMEROUS TSRA THAT HAD BEEN OCCURRING ACROSS SRN KS HAVE VENTURED
S OVER EXTREME NRN OK....HOWEVER A FEW ISOLD TSRA HAVE POPPED UP OVER
SC KS ~35NM NE OF KICT & WITH THESE CELLS MOVG S ~10KTS HAVE ASSIGNED
"VCTS" TO KICT TIL 02Z. ALL 5 TERMINALS TO MAINTAIN VFR STATUS UNTIL
FURTHER NOTICE AS MASSIVE...VERY STRONG UPR-DECK HIGH PRESSURE COVERS
NEARLY ALL OF U.S.
&&
.PREV DISCUSSION... /ISSUED 348 PM CDT THU JUL 19 2012/
DISCUSSION...
ISOLATED SHOWERS AND THUNDERSTORMS WITH A THREAT FOR WIND GUSTS TO
55 MPH MAY LINGER THROUGH THE EARLY EVENING HOURS BEFORE DRIFTING
SOUTH/DIMINISHING IN THE ABSENCE OF HEATING.
A MORE SUBSIDENT REGIME IS ANTICIPATED OVER THE WEEKEND AS THE H5
RIDGE EXPANDS ACROSS THE CENTRAL PLAINS. THE H85-H7 THERMAL
RIDGE/INCREASE IN THICKNESS CONTINUES TO SUPPORT RISING TEMPERATURES
WITH VALUES IN THE 105-109 DEGREE RANGE ANTICIPATED. DEEP VERTICAL
MIXING WILL ALLOW DEWPOINT TEMPERATURES TO PLUMMET DURING THE
AFTERNOON HOURS BUT HEAT INDICES WILL STILL MANAGE TO CLIMB TO
AROUND 105+ DEGREES AT TIMES. THEREFORE THE HEAT ADVISORY WILL BE
EXPANDED THROUGH TUESDAY.
WED-THU...ALTHOUGH TEMPERATURES ARE EXPECTED TO REMAIN WELL ABOVE
NORMAL/POSSIBLY LINGERING IN THE 100-105 DEGREE RANGE THERE MAY BE A
TEMPORARY BREAK DOWN OF THE MID/UPPER RIDGE TOWARD THE MIDDLE OF THE
WEEK AS A ROBUST MID/UPPER TROUGH TRANSLATES EAST ALONG THE
US/CANADIAN BORDER. IF THE RIDGE DOES TEMPORARILY BREAK DOWN IT MAY
BE FAIRLY SHORT-LIVED SO ONLY A SUBTLE TREND DOWN IN TEMPERATURES
WAS INTRODUCED ON THU.
AVIATION...18Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
TOUGH CONVECTIVE FORECAST. STORMS HAVE LINGERED ALONG A COUPLE OF
WEAK BOUNDARIES AND OUTFLOW FROM EARLIER STORMS. LATEST RUC
SEEMS HAVE BETTER HANDLE ON THE CURRENT OBSERVATIONS AND VERY SHORT
TERM TRENDS THAN OTHER GUIDANCE. THIS KEEPS BOUNDARY NORTH OF
KICT/KCNU THROUGH AT LEAST EARLY EVENING AND THEN WILL BLEND INTO
NAM AS BOUNDARY SAGS SOUTH DURING THE NIGHT. OF NOTE RUC SHUTS
DOWN MOST OF THE PRECIPITATION BY 2100 UTC. -HOWERTON
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 75 106 75 105 / 20 10 10 0
HUTCHINSON 76 105 75 103 / 20 10 10 0
NEWTON 78 104 78 103 / 20 10 10 0
ELDORADO 76 104 76 102 / 20 10 0 0
WINFIELD-KWLD 78 107 78 105 / 30 10 10 0
RUSSELL 71 105 71 107 / 10 0 10 0
GREAT BEND 73 105 72 106 / 10 10 10 0
SALINA 74 105 74 105 / 10 10 10 0
MCPHERSON 72 104 73 104 / 20 10 10 0
COFFEYVILLE 78 104 78 103 / 30 10 10 10
CHANUTE 77 101 76 100 / 20 10 10 10
IOLA 75 100 76 101 / 20 10 10 10
PARSONS-KPPF 77 102 77 102 / 30 10 10 10
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY UNTIL 7 PM CDT TUESDAY FOR KSZ032-033-047>053-
067>072-082-083-091>096-098>100.
&&
$$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1200 PM CDT WED JUL 18 2012
...UPDATE TO AVIATION FOR 18Z TAFS...
.SYNOPSIS...
ISSUED AT 917 AM CDT WED JUL 18 2012
THE 18.12Z 250 HPA SYNOPTIC MAP SHOWED A 50 TO 60 KT CYCLONIC CIRCULATION
STILL ACROSS THE PACIFIC NORTHWEST AND EXTENDING SOUTHWARD ACROSS NORTHERN
CALIFORNIA. A ~100 KT JET STREAK WAS LOCATED ACROSS SOUTHEASTERN CANADA.
OTHERWISE, FLOW AT JET LEVEL WAS FAIRLY WEAK ACROSS MOST OF THE COUNTRY
AS ONE WOULD EXPECT DURING THE SUMMER. @ 500 HPA, AN ABNORMALLY STRONG
569 DM LOW WAS SPINNING ACROSS NORTHWESTERN CALIFORNIA. A COLD POOL
OF -17 DEG C WAS ASSOCIATED WITH SAID FEATURE. TWO 590 DM HIGH PRESSURE
CENTERS WERE LOCATED CLOSER TO KANSAS. ONE ACROSS THE SOUTHERN ROCKIES
AND THE OTHER ACROSS THE OZARKS. A WEAK CYCLONE WAS FOUND ACROSS GEORGIA.
AT 700/850 HPA, THE WARM/DRY PLUME WAS STILL OBVIOUS ACROSS THE PLAINS
WITH 700 HPA TEMPERATURES RUNNING IN THE 12 TO 13 DEG C RANGE AND 850
HPA TEMPERATURES IN THE 25 TO 26 DEG C RANGE. AT THE SFC, A TROUGH AXIS
WAS LOCATED ACROSS KANSAS.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 226 AM CDT WED JUL 18 2012
CLOUDS INCREASING IN AREAL COVERAGE EARLY THIS MORNING NEAR A
500MB DEFORMATION ZONE/COL BASED ON 00Z ANALYSIS. ALL THE MODELS
PICK UP ON THIS FEATHER AND INCREASE 700MB RELATIVE HUMIDITY
VALUES EARLY THIS MORNING. THE HRRR EVEN SUGGESTS SOME LIGHT
PRECIPITATION WILL BE POSSIBLE. BASED ON LATEST RADAR TRENDS WILL
FOLLOW THE HRRR AND INTRODUCE SOME LIGHT PRECIPITATION EARLY THIS
MORNING IN SOUTH CENTRAL KANSAS.
AN UPPER LEVEL RIDGE WILL THEN BUILD ACROSS THE CENTRAL AND
NORTHERN ROCKIES LATER TODAY AS THE CENTER OF THIS HIGH, LOCATED
OVER COLORADO, MOVES VERY LITTLE. MODELS REMAIN IN GOOD AGREEMENT
IN MOVING A SURFACE BOUNDARY ACROSS WESTERN KANSAS DURING THE EARLY
MORNING HOURS AND BY THE EARLY AFTERNOON THIS BOUNDARY IS EXPECTED
TO EXTEND FROM HAYS TO GARDEN CITY TO NEAR ELKHART. FORECAST MODEL
SOUNDINGS NEAR THIS SURFACE TROUGH INDICATED SOME MID LEVEL
INSTABILITY AND MOISTURE IN THE 700-600MB LEVEL WILL BE PRESENT AS
AN UPPER LEVEL DISTURBANCE ROTATES AROUND THE UPPER HIGH AND
CROSSES INTO WESTERN KANSAS. GIVEN THE ESTIMATED TIMING OF THIS
UPPER LEVEL DISTURBANCE ALONG WITH WHERE THE BETTER THE LATE DAY
INSTABILITY IS EXPECTED WILL INCREASE THE PRECIPITATION CHANCES
NEAR THE SURFACE BOUNDARY LATE THIS AFTERNOON...ESPECIALLY IN
NORTH CENTRAL KANSAS. THE INVERTED V TYPE OF SOUNDINGS CONTINUE TO
SUGGEST THE PREVIOUS SHIFT HAD THE RIGHT IDEA WITH THE PRIMARY
HAZARD BEING WINDS GUSTY UP TO 45 MPH AND CLOUD TO GROUND
LIGHTNING.
CLOUD COVER THIS AFTERNOON WILL PLAY AN IMPORTANT ROLE ON
TEMPERATURES TODAY. MIXING DOWN THE NAM AND ECMWF 850MB
TEMPERATURES AT 00Z THURSDAY SUGGESTS HIGHS WILL BE MAINLY IN THE
100 TO 104 DEGREE RANGE. INCREASING AFTERNOON CLOUDS AHEAD OF THE
UPPER LEVEL DISTURBANCE HOWEVER MAY RESULT IN KEEPING TEMPERATURES
SEVERAL DEGREES COOLER THAN THIS. AT THIS TIME THERE STILL APPEARS
TO BE A DECENT AMOUNT OF AFTERNOON SUNSHINE SO WILL CONTINUE TO
TREND TOWARDS THE WARMER NAM/ECMWF SOLUTION WHICH HAPPENS TO BE
VERY SIMILAR TO THE PREVIOUS FORECAST.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 337 AM CDT WED JUL 18 2012
THE GENERAL UPPER-LEVEL PATTERN THROUGH JULY 25TH WILL FEATURE
UPPER-LEVEL RIDGING OVER KANSAS AND UPPER-LEVEL SHORTWAVE TROUGHS
POSITIONED FAR TO THE NORTH AND WEST OF KANSAS ACROSS THE NORTHERN
ROCKIES AND SOUTHERN CANADA. HOT WEATHER WILL PERSIST THROUGHOUT THIS
PERIOD. 500MB HEIGHTS ARE PROGGED TO RISE THIS WEEK FROM 589 TO
596 DM AND THIS IMPLIES LOW TO MID-LEVEL WARMING GIVEN THAT SEA
LEVEL PRESSURE VALUES ARE EXPECTED TO CHANGE VERY LITTLE. SO HIGHS
SHOULD BE WELL OVER 100 FOR MOST OF SOUTHWEST KANSAS, EXCEPT
CLOSER TO 100 NEAR THE COLORADO BORDER. SOME READINGS NEAR
107-109F ARE POSSIBLE BY MONDAY AND TUESDAY.
THE SLOW MOVING FRONTAL BOUNDARY MENTIONED IN THE SHORT TERM DISCUSSION
THAT IS CURRENTLY OVER NORTHWEST KANSAS WILL STALL OUT IN THE MIDDLE
OF THE UPPER-LEVEL RIDGE AXIS SOMEWHERE OVER SOUTHWEST KANSAS ON
THURSDAY. THEREFORE, THERE IS A SMALL CHANCE FOR THUNDERSTORMS
WHEREVER THIS BOUNDARY STALLS OUT AND THIS IS HARD TO PINPOINT AT
THIS TIME. SO SMALL CHANCES FOR STORMS WERE INTRODUCED FOR MUCH OF
THE FORECAST AREA. EVEN THOUGH THE LOW-LEVEL MOISTURE IS MIXING
OUT IN THE HOT PLUME AS IT TRIES TO MOVE NORTHWARD INTO THE
PLAINS, SOME SURFACE BASED CAPE BETWEEN 400 AND 800 J/KG, ALONG
WITH MODEST LOW-LEVEL CONVERGENCE AND STRONG SURFACE HEATING MAY
BE ENOUGH TO INITIATE A FEW HIGH BASED THUNDERSTORMS. GIVEN THE
LOW CAPE VALUES, VERY LOW VERTICAL WIND SHEAR AND HIGH CLOUD
BASES, THE MAIN THREAT WITH THESE STORMS IS GUSTY WINDS AS HIGH AS
50 MPH AS WELL AS ANY CLOUD TO GROUND LIGHTNING.
AFTER THURSDAY, THERE IS LITTLE IN THE WAY OF HOPE FOR THUNDERSTORMS
THROUGH JULY 25TH GIVEN THE AFOREMENTIONED STRONG UPPER-LEVEL
RIDGING AND ABSENCE OF FRONTS. HOWEVER, THE LONGER RANGE MODELS
ARE OFTEN UNABLE TO RESOLVE SMALLER SCALE BOUNDARIES THAT COULD
SERVE TO INITIATE ISOLATED THUNDERSTORMS. BUT IT IS PROBABLY SAFE
TO SAY THAT WIDESPREAD BENEFICIAL RAINS ARE HIGHLY UNLIKELY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1200 PM CDT WED JUL 18 2012
A SURFACE TROUGH AXIS BISECTING THE REGION WILL ULTIMATELY LEAD TO
LIGHT AND VARIABLE WINDS TODAY. 5 TO 10 KT SOUTHERLY WINDS EXPECTED
THIS EVENING AS THE TROUGH AXIS REFORMS FARTHER WEST. OTHERWISE, VFR
CIGS EXPECTED TODAY. ISOLATED THUNDERSTORMS ARE POSSIBLE THIS AFTERNOON
BUT DON`T THINK ANY REDUCTION IN CIGS WILL RESULT. SINCE THE ACTIVITY
WILL BE VERY ISOLATED...WILL LEAVE TS/CB GROUPS OUT FOR NOW.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 101 72 103 74 / 10 20 20 20
GCK 100 69 101 73 / 20 20 20 10
EHA 98 70 100 72 / 10 20 0 0
LBL 101 69 101 73 / 10 20 10 0
HYS 104 73 106 76 / 20 20 20 20
P28 104 73 105 77 / 20 10 20 20
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...SUGDEN
SHORT TERM...BURGERT
LONG TERM...FINCH
AVIATION...SUGDEN
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
917 AM CDT WED JUL 18 2012
...UPDATE TO SYNOPSIS...
.SYNOPSIS...
ISSUED AT 917 AM CDT WED JUL 18 2012
THE 18.12Z 250 HPA SYNOPTIC MAP SHOWED A 50 TO 60 KT CYCLONIC CIRCULATION
STILL ACROSS THE PACIFIC NORTHWEST AND EXTENDING SOUTHWARD ACROSS NORTHERN
CALIFORNIA. A ~100 KT JET STREAK WAS LOCATED ACROSS SOUTHEASTERN CANADA.
OTHERWISE, FLOW AT JET LEVEL WAS FAIRLY WEAK ACROSS MOST OF THE COUNTRY
AS ONE WOULD EXPECT DURING THE SUMMER. @ 500 HPA, AN ABNORMALLY STRONG
569 DM LOW WAS SPINNING ACROSS NORTHWESTERN CALIFORNIA. A COLD POOL
OF -17 DEG C WAS ASSOCIATED WITH SAID FEATURE. TWO 590 DM HIGH PRESSURE
CENTERS WERE LOCATED CLOSER TO KANSAS. ONE ACROSS THE SOUTHERN ROCKIES
AND THE OTHER ACROSS THE OZARKS. A WEAK CYCLONE WAS FOUND ACROSS GEORGIA.
AT 700/850 HPA, THE WARM/DRY PLUME WAS STILL OBVIOUS ACROSS THE PLAINS
WITH 700 HPA TEMPERATURES RUNNING IN THE 12 TO 13 DEG C RANGE AND 850
HPA TEMPERATURES IN THE 25 TO 26 DEG C RANGE. AT THE SFC, A TROUGH AXIS
WAS LOCATED ACROSS KANSAS.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 226 AM CDT WED JUL 18 2012
CLOUDS INCREASING IN AREAL COVERAGE EARLY THIS MORNING NEAR A
500MB DEFORMATION ZONE/COL BASED ON 00Z ANALYSIS. ALL THE MODELS
PICK UP ON THIS FEATHER AND INCREASE 700MB RELATIVE HUMIDITY
VALUES EARLY THIS MORNING. THE HRRR EVEN SUGGESTS SOME LIGHT
PRECIPITATION WILL BE POSSIBLE. BASED ON LATEST RADAR TRENDS WILL
FOLLOW THE HRRR AND INTRODUCE SOME LIGHT PRECIPITATION EARLY THIS
MORNING IN SOUTH CENTRAL KANSAS.
AN UPPER LEVEL RIDGE WILL THEN BUILD ACROSS THE CENTRAL AND
NORTHERN ROCKIES LATER TODAY AS THE CENTER OF THIS HIGH, LOCATED
OVER COLORADO, MOVES VERY LITTLE. MODELS REMAIN IN GOOD AGREEMENT
IN MOVING A SURFACE BOUNDARY ACROSS WESTERN KANSAS DURING THE EARLY
MORNING HOURS AND BY THE EARLY AFTERNOON THIS BOUNDARY IS EXPECTED
TO EXTEND FROM HAYS TO GARDEN CITY TO NEAR ELKHART. FORECAST MODEL
SOUNDINGS NEAR THIS SURFACE TROUGH INDICATED SOME MID LEVEL
INSTABILITY AND MOISTURE IN THE 700-600MB LEVEL WILL BE PRESENT AS
AN UPPER LEVEL DISTURBANCE ROTATES AROUND THE UPPER HIGH AND
CROSSES INTO WESTERN KANSAS. GIVEN THE ESTIMATED TIMING OF THIS
UPPER LEVEL DISTURBANCE ALONG WITH WHERE THE BETTER THE LATE DAY
INSTABILITY IS EXPECTED WILL INCREASE THE PRECIPITATION CHANCES
NEAR THE SURFACE BOUNDARY LATE THIS AFTERNOON...ESPECIALLY IN
NORTH CENTRAL KANSAS. THE INVERTED V TYPE OF SOUNDINGS CONTINUE TO
SUGGEST THE PREVIOUS SHIFT HAD THE RIGHT IDEA WITH THE PRIMARY
HAZARD BEING WINDS GUSTY UP TO 45 MPH AND CLOUD TO GROUND
LIGHTNING.
CLOUD COVER THIS AFTERNOON WILL PLAY AN IMPORTANT ROLE ON
TEMPERATURES TODAY. MIXING DOWN THE NAM AND ECMWF 850MB
TEMPERATURES AT 00Z THURSDAY SUGGESTS HIGHS WILL BE MAINLY IN THE
100 TO 104 DEGREE RANGE. INCREASING AFTERNOON CLOUDS AHEAD OF THE
UPPER LEVEL DISTURBANCE HOWEVER MAY RESULT IN KEEPING TEMPERATURES
SEVERAL DEGREES COOLER THAN THIS. AT THIS TIME THERE STILL APPEARS
TO BE A DECENT AMOUNT OF AFTERNOON SUNSHINE SO WILL CONTINUE TO
TREND TOWARDS THE WARMER NAM/ECMWF SOLUTION WHICH HAPPENS TO BE
VERY SIMILAR TO THE PREVIOUS FORECAST.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 337 AM CDT WED JUL 18 2012
THE GENERAL UPPER-LEVEL PATTERN THROUGH JULY 25TH WILL FEATURE
UPPER-LEVEL RIDGING OVER KANSAS AND UPPER-LEVEL SHORTWAVE TROUGHS
POSITIONED FAR TO THE NORTH AND WEST OF KANSAS ACROSS THE NORTHERN
ROCKIES AND SOUTHERN CANADA. HOT WEATHER WILL PERSIST THROUGHOUT THIS
PERIOD. 500MB HEIGHTS ARE PROGGED TO RISE THIS WEEK FROM 589 TO
596 DM AND THIS IMPLIES LOW TO MID-LEVEL WARMING GIVEN THAT SEA
LEVEL PRESSURE VALUES ARE EXPECTED TO CHANGE VERY LITTLE. SO HIGHS
SHOULD BE WELL OVER 100 FOR MOST OF SOUTHWEST KANSAS, EXCEPT
CLOSER TO 100 NEAR THE COLORADO BORDER. SOME READINGS NEAR
107-109F ARE POSSIBLE BY MONDAY AND TUESDAY.
THE SLOW MOVING FRONTAL BOUNDARY MENTIONED IN THE SHORT TERM DISCUSSION
THAT IS CURRENTLY OVER NORTHWEST KANSAS WILL STALL OUT IN THE MIDDLE
OF THE UPPER-LEVEL RIDGE AXIS SOMEWHERE OVER SOUTHWEST KANSAS ON
THURSDAY. THEREFORE, THERE IS A SMALL CHANCE FOR THUNDERSTORMS
WHEREVER THIS BOUNDARY STALLS OUT AND THIS IS HARD TO PINPOINT AT
THIS TIME. SO SMALL CHANCES FOR STORMS WERE INTRODUCED FOR MUCH OF
THE FORECAST AREA. EVEN THOUGH THE LOW-LEVEL MOISTURE IS MIXING
OUT IN THE HOT PLUME AS IT TRIES TO MOVE NORTHWARD INTO THE
PLAINS, SOME SURFACE BASED CAPE BETWEEN 400 AND 800 J/KG, ALONG
WITH MODEST LOW-LEVEL CONVERGENCE AND STRONG SURFACE HEATING MAY
BE ENOUGH TO INITIATE A FEW HIGH BASED THUNDERSTORMS. GIVEN THE
LOW CAPE VALUES, VERY LOW VERTICAL WIND SHEAR AND HIGH CLOUD
BASES, THE MAIN THREAT WITH THESE STORMS IS GUSTY WINDS AS HIGH AS
50 MPH AS WELL AS ANY CLOUD TO GROUND LIGHTNING.
AFTER THURSDAY, THERE IS LITTLE IN THE WAY OF HOPE FOR THUNDERSTORMS
THROUGH JULY 25TH GIVEN THE AFOREMENTIONED STRONG UPPER-LEVEL
RIDGING AND ABSENCE OF FRONTS. HOWEVER, THE LONGER RANGE MODELS
ARE OFTEN UNABLE TO RESOLVE SMALLER SCALE BOUNDARIES THAT COULD
SERVE TO INITIATE ISOLATED THUNDERSTORMS. BUT IT IS PROBABLY SAFE
TO SAY THAT WIDESPREAD BENEFICIAL RAINS ARE HIGHLY UNLIKELY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 657 AM CDT WED JUL 18 2012
LIGHT SOUTHWESTERLY WINDS WILL BECOME LIGHT AS A WEAK FRONT STALLS OUT
ACROSS THE TAF SITES THIS AFTERNOON. ISOLATED THUNDERSTORMS MAY
DEVELOP AFTER 21Z ALONG THIS FRONT IN VICINITY OF THE TAF SITES.
VFR CONDITIONS WILL PREVAIL.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 101 72 103 74 / 10 20 20 20
GCK 100 69 101 73 / 20 20 20 10
EHA 98 70 100 72 / 10 20 0 0
LBL 101 69 101 73 / 10 20 10 0
HYS 104 73 106 76 / 20 20 20 20
P28 104 73 105 77 / 20 10 20 20
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...SUGDEN
SHORT TERM...BURGERT
LONG TERM...FINCH
AVIATION...FINCH
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
659 AM CDT WED JUL 18 2012
...UPDATED FOR AVIATION DISCUSSION...
.SYNOPSIS...
ISSUED AT 1211 AM CDT WED JUL 18 2012
A -17C 500MB LOW WAS LOCATED OVER NORTHERN CALIFORNIA AS OF 00Z
WEDNESDAY. STRONGEST 250MB WINDS AROUND THIS UPPER LOW EXTENDED FROM
THE BASE OF THIS UPPER LOW NORTHEASTWARD INTO EASTERN
OREGON/SOUTHWEST IDAHO. AN UPPER LEVEL RIDGE EXTENDED FROM NORTHERN
NEW MEXICO INTO EASTERN WYOMING AT 00Z WEDNESDAY WITH THE CENTER
OF THIS ANTICYCLONIC FLOW APPEARING TO BE LOCATED OVER SOUTHERN
COLORADO BASED ON 500MB ANALYSIS. A TROUGH OF LOW PRESSURE AT THE
SURFACE AT 01Z EXTENDED FROM NORTH CENTRAL KANSAS INTO SOUTHEAST
COLORADO. THE LATEST RADAR LOOP, AS OF 05Z, INDICATED THAT SEVERAL
OUTFLOW BOUNDARIES FROM THE CONVECTION THAT DEVELOPED EARLIER THIS
EVENING NEAR THIS BOUNDARY WERE NOW LOCATED ACROSS WESTERN AND
NORTH CENTRAL KANSAS.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 226 AM CDT WED JUL 18 2012
CLOUDS INCREASING IN AREAL COVERAGE EARLY THIS MORNING NEAR A
500MB DEFORMATION ZONE/COL BASED ON 00Z ANALYSIS. ALL THE MODELS
PICK UP ON THIS FEATHER AND INCREASE 700MB RELATIVE HUMIDITY
VALUES EARLY THIS MORNING. THE HRRR EVEN SUGGESTS SOME LIGHT
PRECIPITATION WILL BE POSSIBLE. BASED ON LATEST RADAR TRENDS WILL
FOLLOW THE HRRR AND INTRODUCE SOME LIGHT PRECIPITATION EARLY THIS
MORNING IN SOUTH CENTRAL KANSAS.
AN UPPER LEVEL RIDGE WILL THEN BUILD ACROSS THE CENTRAL AND
NORTHERN ROCKIES LATER TODAY AS THE CENTER OF THIS HIGH, LOCATED
OVER COLORADO, MOVES VERY LITTLE. MODELS REMAIN IN GOOD AGREEMENT
IN MOVING A SURFACE BOUNDARY ACROSS WESTERN KANSAS DURING THE EARLY
MORNING HOURS AND BY THE EARLY AFTERNOON THIS BOUNDARY IS EXPECTED
TO EXTEND FROM HAYS TO GARDEN CITY TO NEAR ELKHART. FORECAST MODEL
SOUNDINGS NEAR THIS SURFACE TROUGH INDICATED SOME MID LEVEL
INSTABILITY AND MOISTURE IN THE 700-600MB LEVEL WILL BE PRESENT AS
AN UPPER LEVEL DISTURBANCE ROTATES AROUND THE UPPER HIGH AND
CROSSES INTO WESTERN KANSAS. GIVEN THE ESTIMATED TIMING OF THIS
UPPER LEVEL DISTURBANCE ALONG WITH WHERE THE BETTER THE LATE DAY
INSTABILITY IS EXPECTED WILL INCREASE THE PRECIPITATION CHANCES
NEAR THE SURFACE BOUNDARY LATE THIS AFTERNOON...ESPECIALLY IN
NORTH CENTRAL KANSAS. THE INVERTED V TYPE OF SOUNDINGS CONTINUE TO
SUGGEST THE PREVIOUS SHIFT HAD THE RIGHT IDEA WITH THE PRIMARY
HAZARD BEING WINDS GUSTY UP TO 45 MPH AND CLOUD TO GROUND
LIGHTNING.
CLOUD COVER THIS AFTERNOON WILL PLAY AN IMPORTANT ROLE ON
TEMPERATURES TODAY. MIXING DOWN THE NAM AND ECMWF 850MB
TEMPERATURES AT 00Z THURSDAY SUGGESTS HIGHS WILL BE MAINLY IN THE
100 TO 104 DEGREE RANGE. INCREASING AFTERNOON CLOUDS AHEAD OF THE
UPPER LEVEL DISTURBANCE HOWEVER MAY RESULT IN KEEPING TEMPERATURES
SEVERAL DEGREES COOLER THAN THIS. AT THIS TIME THERE STILL APPEARS
TO BE A DECENT AMOUNT OF AFTERNOON SUNSHINE SO WILL CONTINUE TO
TREND TOWARDS THE WARMER NAM/ECMWF SOLUTION WHICH HAPPENS TO BE
VERY SIMILAR TO THE PREVIOUS FORECAST.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 337 AM CDT WED JUL 18 2012
THE GENERAL UPPER-LEVEL PATTERN THROUGH JULY 25TH WILL FEATURE
UPPER-LEVEL RIDGING OVER KANSAS AND UPPER-LEVEL SHORTWAVE TROUGHS
POSITIONED FAR TO THE NORTH AND WEST OF KANSAS ACROSS THE NORTHERN
ROCKIES AND SOUTHERN CANADA. HOT WEATHER WILL PERSIST THROUGHOUT THIS
PERIOD. 500MB HEIGHTS ARE PROGGED TO RISE THIS WEEK FROM 589 TO
596 DM AND THIS IMPLIES LOW TO MID-LEVEL WARMING GIVEN THAT SEA
LEVEL PRESSURE VALUES ARE EXPECTED TO CHANGE VERY LITTLE. SO HIGHS
SHOULD BE WELL OVER 100 FOR MOST OF SOUTHWEST KANSAS, EXCEPT
CLOSER TO 100 NEAR THE COLORADO BORDER. SOME READINGS NEAR
107-109F ARE POSSIBLE BY MONDAY AND TUESDAY.
THE SLOW MOVING FRONTAL BOUNDARY MENTIONED IN THE SHORT TERM DISCUSSION
THAT IS CURRENTLY OVER NORTHWEST KANSAS WILL STALL OUT IN THE MIDDLE
OF THE UPPER-LEVEL RIDGE AXIS SOMEWHERE OVER SOUTHWEST KANSAS ON
THURSDAY. THEREFORE, THERE IS A SMALL CHANCE FOR THUNDERSTORMS
WHEREVER THIS BOUNDARY STALLS OUT AND THIS IS HARD TO PINPOINT AT
THIS TIME. SO SMALL CHANCES FOR STORMS WERE INTRODUCED FOR MUCH OF
THE FORECAST AREA. EVEN THOUGH THE LOW-LEVEL MOISTURE IS MIXING
OUT IN THE HOT PLUME AS IT TRIES TO MOVE NORTHWARD INTO THE
PLAINS, SOME SURFACE BASED CAPE BETWEEN 400 AND 800 J/KG, ALONG
WITH MODEST LOW-LEVEL CONVERGENCE AND STRONG SURFACE HEATING MAY
BE ENOUGH TO INITIATE A FEW HIGH BASED THUNDERSTORMS. GIVEN THE
LOW CAPE VALUES, VERY LOW VERTICAL WIND SHEAR AND HIGH CLOUD
BASES, THE MAIN THREAT WITH THESE STORMS IS GUSTY WINDS AS HIGH AS
50 MPH AS WELL AS ANY CLOUD TO GROUND LIGHTNING.
AFTER THURSDAY, THERE IS LITTLE IN THE WAY OF HOPE FOR THUNDERSTORMS
THROUGH JULY 25TH GIVEN THE AFOREMENTIONED STRONG UPPER-LEVEL
RIDGING AND ABSENCE OF FRONTS. HOWEVER, THE LONGER RANGE MODELS
ARE OFTEN UNABLE TO RESOLVE SMALLER SCALE BOUNDARIES THAT COULD
SERVE TO INITIATE ISOLATED THUNDERSTORMS. BUT IT IS PROBABLY SAFE
TO SAY THAT WIDESPREAD BENEFICIAL RAINS ARE HIGHLY UNLIKELY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 657 AM CDT WED JUL 18 2012
LIGHT SOUTHWESTERLY WINDS WILL BECOME LIGHT AS A WEAK FRONT STALLS OUT
ACROSS THE TAF SITES THIS AFTERNOON. ISOLATED THUNDERSTORMS MAY
DEVELOP AFTER 21Z ALONG THIS FRONT IN VICINITY OF THE TAF SITES.
VFR CONDITIONS WILL PREVAIL.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 101 72 103 74 / 10 20 20 20
GCK 100 69 101 73 / 20 20 20 10
EHA 98 70 100 72 / 10 20 0 0
LBL 101 69 101 73 / 10 20 10 0
HYS 104 73 106 76 / 20 20 20 20
P28 104 73 105 77 / 20 10 20 20
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BURGERT
SHORT TERM...BURGERT
LONG TERM...FINCH
AVIATION...FINCH
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
344 AM CDT WED JUL 18 2012
...UPDATED FOR LONG TERM DISCUSSION...
.SYNOPSIS...
ISSUED AT 1211 AM CDT WED JUL 18 2012
A -17C 500MB LOW WAS LOCATED OVER NORTHERN CALIFORNIA AS OF 00Z
WEDNESDAY. STRONGEST 250MB WINDS AROUND THIS UPPER LOW EXTENDED FROM
THE BASE OF THIS UPPER LOW NORTHEASTWARD INTO EASTERN
OREGON/SOUTHWEST IDAHO. AN UPPER LEVEL RIDGE EXTENDED FROM NORTHERN
NEW MEXICO INTO EASTERN WYOMING AT 00Z WEDNESDAY WITH THE CENTER
OF THIS ANTICYCLONIC FLOW APPEARING TO BE LOCATED OVER SOUTHERN
COLORADO BASED ON 500MB ANALYSIS. A TROUGH OF LOW PRESSURE AT THE
SURFACE AT 01Z EXTENDED FROM NORTH CENTRAL KANSAS INTO SOUTHEAST
COLORADO. THE LATEST RADAR LOOP, AS OF 05Z, INDICATED THAT SEVERAL
OUTFLOW BOUNDARIES FROM THE CONVECTION THAT DEVELOPED EARLIER THIS
EVENING NEAR THIS BOUNDARY WERE NOW LOCATED ACROSS WESTERN AND
NORTH CENTRAL KANSAS.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 226 AM CDT WED JUL 18 2012
CLOUDS INCREASING IN AREAL COVERAGE EARLY THIS MORNING NEAR A
500MB DEFORMATION ZONE/COL BASED ON 00Z ANALYSIS. ALL THE MODELS
PICK UP ON THIS FEATHER AND INCREASE 700MB RELATIVE HUMIDITY
VALUES EARLY THIS MORNING. THE HRRR EVEN SUGGESTS SOME LIGHT
PRECIPITATION WILL BE POSSIBLE. BASED ON LATEST RADAR TRENDS WILL
FOLLOW THE HRRR AND INTRODUCE SOME LIGHT PRECIPITATION EARLY THIS
MORNING IN SOUTH CENTRAL KANSAS.
AN UPPER LEVEL RIDGE WILL THEN BUILD ACROSS THE CENTRAL AND
NORTHERN ROCKIES LATER TODAY AS THE CENTER OF THIS HIGH, LOCATED
OVER COLORADO, MOVES VERY LITTLE. MODELS REMAIN IN GOOD AGREEMENT
IN MOVING A SURFACE BOUNDARY ACROSS WESTERN KANSAS DURING THE EARLY
MORNING HOURS AND BY THE EARLY AFTERNOON THIS BOUNDARY IS EXPECTED
TO EXTEND FROM HAYS TO GARDEN CITY TO NEAR ELKHART. FORECAST MODEL
SOUNDINGS NEAR THIS SURFACE TROUGH INDICATED SOME MID LEVEL
INSTABILITY AND MOISTURE IN THE 700-600MB LEVEL WILL BE PRESENT AS
AN UPPER LEVEL DISTURBANCE ROTATES AROUND THE UPPER HIGH AND
CROSSES INTO WESTERN KANSAS. GIVEN THE ESTIMATED TIMING OF THIS
UPPER LEVEL DISTURBANCE ALONG WITH WHERE THE BETTER THE LATE DAY
INSTABILITY IS EXPECTED WILL INCREASE THE PRECIPITATION CHANCES
NEAR THE SURFACE BOUNDARY LATE THIS AFTERNOON...ESPECIALLY IN
NORTH CENTRAL KANSAS. THE INVERTED V TYPE OF SOUNDINGS CONTINUE TO
SUGGEST THE PREVIOUS SHIFT HAD THE RIGHT IDEA WITH THE PRIMARY
HAZARD BEING WINDS GUSTY UP TO 45 MPH AND CLOUD TO GROUND
LIGHTNING.
CLOUD COVER THIS AFTERNOON WILL PLAY AN IMPORTANT ROLE ON
TEMPERATURES TODAY. MIXING DOWN THE NAM AND ECMWF 850MB
TEMPERATURES AT 00Z THURSDAY SUGGESTS HIGHS WILL BE MAINLY IN THE
100 TO 104 DEGREE RANGE. INCREASING AFTERNOON CLOUDS AHEAD OF THE
UPPER LEVEL DISTURBANCE HOWEVER MAY RESULT IN KEEPING TEMPERATURES
SEVERAL DEGREES COOLER THAN THIS. AT THIS TIME THERE STILL APPEARS
TO BE A DECENT AMOUNT OF AFTERNOON SUNSHINE SO WILL CONTINUE TO
TREND TOWARDS THE WARMER NAM/ECMWF SOLUTION WHICH HAPPENS TO BE
VERY SIMILAR TO THE PREVIOUS FORECAST.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 337 AM CDT WED JUL 18 2012
THE GENERAL UPPER-LEVEL PATTERN THROUGH JULY 25TH WILL FEATURE
UPPER-LEVEL RIDGING OVER KANSAS AND UPPER-LEVEL SHORTWAVE TROUGHS
POSITIONED FAR TO THE NORTH AND WEST OF KANSAS ACROSS THE NORTHERN
ROCKIES AND SOUTHERN CANADA. HOT WEATHER WILL PERSIST THROUGHOUT THIS
PERIOD. 500MB HEIGHTS ARE PROGGED TO RISE THIS WEEK FROM 589 TO
596 DM AND THIS IMPLIES LOW TO MID-LEVEL WARMING GIVEN THAT SEA
LEVEL PRESSURE VALUES ARE EXPECTED TO CHANGE VERY LITTLE. SO HIGHS
SHOULD BE WELL OVER 100 FOR MOST OF SOUTHWEST KANSAS, EXCEPT
CLOSER TO 100 NEAR THE COLORADO BORDER. SOME READINGS NEAR
107-109F ARE POSSIBLE BY MONDAY AND TUESDAY.
THE SLOW MOVING FRONTAL BOUNDARY MENTIONED IN THE SHORT TERM DISCUSSION
THAT IS CURRENTLY OVER NORTHWEST KANSAS WILL STALL OUT IN THE MIDDLE
OF THE UPPER-LEVEL RIDGE AXIS SOMEWHERE OVER SOUTHWEST KANSAS ON
THURSDAY. THEREFORE, THERE IS A SMALL CHANCE FOR THUNDERSTORMS
WHEREVER THIS BOUNDARY STALLS OUT AND THIS IS HARD TO PINPOINT AT
THIS TIME. SO SMALL CHANCES FOR STORMS WERE INTRODUCED FOR MUCH OF
THE FORECAST AREA. EVEN THOUGH THE LOW-LEVEL MOISTURE IS MIXING
OUT IN THE HOT PLUME AS IT TRIES TO MOVE NORTHWARD INTO THE
PLAINS, SOME SURFACE BASED CAPE BETWEEN 400 AND 800 J/KG, ALONG
WITH MODEST LOW-LEVEL CONVERGENCE AND STRONG SURFACE HEATING MAY
BE ENOUGH TO INITIATE A FEW HIGH BASED THUNDERSTORMS. GIVEN THE
LOW CAPE VALUES, VERY LOW VERTICAL WIND SHEAR AND HIGH CLOUD
BASES, THE MAIN THREAT WITH THESE STORMS IS GUSTY WINDS AS HIGH AS
50 MPH AS WELL AS ANY CLOUD TO GROUND LIGHTNING.
AFTER THURSDAY, THERE IS LITTLE IN THE WAY OF HOPE FOR THUNDERSTORMS
THROUGH JULY 25TH GIVEN THE AFOREMENTIONED STRONG UPPER-LEVEL
RIDGING AND ABSENCE OF FRONTS. HOWEVER, THE LONGER RANGE MODELS
ARE OFTEN UNABLE TO RESOLVE SMALLER SCALE BOUNDARIES THAT COULD
SERVE TO INITIATE ISOLATED THUNDERSTORMS. BUT IT IS PROBABLY SAFE
TO SAY THAT WIDESPREAD BENEFICIAL RAINS ARE HIGHLY UNLIKELY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1211 AM CDT WED JUL 18 2012
VARIABLE WINDS CAN BE EXPECTED OVER THE NEXT SEVERAL HOURS AS
SEVERAL OUTFLOW BOUNDARIES CROSS WESTERN KANSAS. AFTER 9Z THE
WINDS ARE EXPECTED TO BECOME SOUTH AGAIN AT AROUND 10KTS. ONLY MID
LEVEL MOISTURE WILL ACCOMPANY AN UPPER LEVEL DISTURBANCE AS IT
CROSSES WESTERN KANSAS EARLY THIS MORNING. IN ADDITION A FEW
WIDELY SCATTERED SHOWERS WILL BE POSSIBLE IN THE HAYS AREA THROUGH
08Z. AFTER 12Z A TROUGH OF LOW PRESSURE WILL SLOWLY MOVE EAST
ACROSS WESTERN KANSAS AND BY 21Z THIS BOUNDARY IS EXPECTED TO
EXTEND FROM NEAR HAYS TO GARDEN CITY. ALONG THIS BOUNDARY WIDELY
SCATTERED THUNDERSTORMS WILL BE POSSIBLE LATE THIS AFTERNOON AND
EARLY THIS EVENING...ESPECIALLY IN NORTH CENTRAL KANSAS NEAR HAYS
BETWEEN 21Z AND 03Z.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 101 72 103 74 / 20 20 20 20
GCK 100 69 101 73 / 20 20 20 10
EHA 98 70 100 72 / 10 20 0 0
LBL 101 69 101 73 / 10 20 10 0
HYS 104 73 106 76 / 20 20 20 20
P28 104 73 105 77 / 20 10 20 20
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BURGERT
SHORT TERM...BURGERT
LONG TERM...FINCH
AVIATION...BURGERT
AREA FORECAST DISCUSSION...CORRECTED
NWS DODGE CITY KS
229 AM CDT WED JUL 18 2012
...UPDATED SHORT TERM DISCUSSION...
.SYNOPSIS...
ISSUED AT 1211 AM CDT WED JUL 18 2012
A -17C 500MB LOW WAS LOCATED OVER NORTHERN CALIFORNIA AS OF 00Z
WEDNESDAY. STRONGEST 250MB WINDS AROUND THIS UPPER LOW EXTENDED FROM
THE BASE OF THIS UPPER LOW NORTHEASTWARD INTO EASTERN
OREGON/SOUTHWEST IDAHO. AN UPPER LEVEL RIDGE EXTENDED FROM NORTHERN
NEW MEXICO INTO EASTERN WYOMING AT 00Z WEDNESDAY WITH THE CENTER
OF THIS ANTICYCLONIC FLOW APPEARING TO BE LOCATED OVER SOUTHERN
COLORADO BASED ON 500MB ANALYSIS. A TROUGH OF LOW PRESSURE AT THE
SURFACE AT 01Z EXTENDED FROM NORTH CENTRAL KANSAS INTO SOUTHEAST
COLORADO. THE LATEST RADAR LOOP, AS OF 05Z, INDICATED THAT SEVERAL
OUTFLOW BOUNDARIES FROM THE CONVECTION THAT DEVELOPED EARLIER THIS
EVENING NEAR THIS BOUNDARY WERE NOW LOCATED ACROSS WESTERN AND
NORTH CENTRAL KANSAS.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 226 AM CDT WED JUL 18 2012
CLOUDS INCREASING IN AREAL COVERAGE EARLY THIS MORNING NEAR A
500MB DEFORMATION ZONE/COL BASED ON 00Z ANALYSIS. ALL THE MODELS
PICK UP ON THIS FEATHER AND INCREASE 700MB RELATIVE HUMIDITY
VALUES EARLY THIS MORNING. THE HRRR EVEN SUGGESTS SOME LIGHT
PRECIPITATION WILL BE POSSIBLE. BASED ON LATEST RADAR TRENDS WILL
FOLLOW THE HRRR AND INTRODUCE SOME LIGHT PRECIPITATION EARLY THIS
MORNING IN SOUTH CENTRAL KANSAS.
AN UPPER LEVEL RIDGE WILL THEN BUILD ACROSS THE CENTRAL AND
NORTHERN ROCKIES LATER TODAY AS THE CENTER OF THIS HIGH, LOCATED
OVER COLORADO, MOVES VERY LITTLE. MODELS REMAIN IN GOOD AGREEMENT
IN MOVING A SURFACE BOUNDARY ACROSS WESTERN KANSAS DURING THE EARLY
MORNING HOURS AND BY THE EARLY AFTERNOON THIS BOUNDARY IS EXPECTED
TO EXTEND FROM HAYS TO GARDEN CITY TO NEAR ELKHART. FORECAST MODEL
SOUNDINGS NEAR THIS SURFACE TROUGH INDICATED SOME MID LEVEL
INSTABILITY AND MOISTURE IN THE 700-600MB LEVEL WILL BE PRESENT AS
AN UPPER LEVEL DISTURBANCE ROTATES AROUND THE UPPER HIGH AND
CROSSES INTO WESTERN KANSAS. GIVEN THE ESTIMATED TIMING OF THIS
UPPER LEVEL DISTURBANCE ALONG WITH WHERE THE BETTER THE LATE DAY
INSTABILITY IS EXPECTED WILL INCREASE THE PRECIPITATION CHANCES
NEAR THE SURFACE BOUNDARY LATE THIS AFTERNOON...ESPECIALLY IN
NORTH CENTRAL KANSAS. THE INVERTED V TYPE OF SOUNDINGS CONTINUE TO
SUGGEST THE PREVIOUS SHIFT HAD THE RIGHT IDEA WITH THE PRIMARY
HAZARD BEING WINDS GUSTY UP TO 45 MPH AND CLOUD TO GROUND
LIGHTNING.
CLOUD COVER THIS AFTERNOON WILL PLAY AN IMPORTANT ROLE ON
TEMPERATURES TODAY. MIXING DOWN THE NAM AND ECMWF 850MB
TEMPERATURES AT 00Z THURSDAY SUGGESTS HIGHS WILL BE MAINLY IN THE
100 TO 104 DEGREE RANGE. INCREASING AFTERNOON CLOUDS AHEAD OF THE
UPPER LEVEL DISTURBANCE HOWEVER MAY RESULT IN KEEPING TEMPERATURES
SEVERAL DEGREES COOLER THAN THIS. AT THIS TIME THERE STILL APPEARS
TO BE A DECENT AMOUNT OF AFTERNOON SUNSHINE SO WILL CONTINUE TO
TREND TOWARDS THE WARMER NAM/ECMWF SOLUTION WHICH HAPPENS TO BE
VERY SIMILAR TO THE PREVIOUS FORECAST.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 238 PM CDT TUE JUL 17 2012
ALOFT, THE PERSISTENT STRONG UPPER LEVEL HIGH PRESSURE AREA, FROM
THE 700, 500, AND 300MB LEVELS AND UPWARDS, WILL REMAIN OVER
KANSAS AND NOT VENTURE TOO FAR THROUGH DAY 7. THIS WILL KEEP HOT
TEMPERATURES GOING THROUGH AT LEAST THE DAY 7 PERIOD, WITH LITTLE
OR NO RELIEF FROM ANY RAIN. MAXIMUM TEMPERATURES WILL AVERAGE
AROUND 100 TO 102F IN THE WEST NEAR THE COLORADO LINE, AND FROM
THE 103 TO 105F RANGE IN THE EASTERN FORECAST AREA NEAR HAYS,
LARNED, PRATT AND MEDICINE LODGE. THE 850MB-1000MB THICKNESS
VALUES FROM THE ECMWF AND GFS MODELS RANGE FROM ABOUT 1440M IN OUR
WEST ZONES TO 1556M IN OUR EAST THURSDAY. BASICALLY, THOSE SAME
RANGES EXIST FROM FRIDAY THROUGH MONDAY. WITH THIS SAID, THERE
COULD BE AN HEAT ADVISORY WARRANTED A DAY OR TWO FOR OUR EASTERN-
MOST COUNTIES FOR A SMALL PERIOD OF THE AFTERNOONS, BUT EXACTLY
WHERE AND HOW LARGE OF AN AREA TO INCLUDE WILL NEED TO BE TAILORED
LATER, AS EACH DAY APPROACHES. FURTHER, DUE TO DEW POINTS ONLY IN
THE MID TO UPPER 50S, THE HEAT INDEX VALUES OF 105F WILL BE HARD
TO REACH. MINIMUM TEMPERATURES WILL BE ELEVATED, AND GENERALLY
RANGE FROM THE LOWER 70S IN OUR WEST ZONES ALONG THE COLORADO
BORDER TO THE UPPER 70S IN OUR EAST NEAR LARNED, PRATT, AND
MEDICINE LODGE.
IN THE NEAR TERM OF THE EXTENDED PERIOD, WEDNESDAY EVENING WILL SEE
A SLIGHT CHANCE FOR THUNDERSTORMS IN OUR NORTHWEST, BASICALLY
NORTHWEST A HAYS TO LIBERAL LINE. A TROUGH OF LOW PRESSURE WILL BE
OVER WESTERN KANSAS WEDNESDAY, AND THE HEATING FROM THE AFTERNOON
WILL PROBABLY TRIGGER WIDELY SCATTERED STORMS WEDNESDAY AFTERNOON
AND LAST INTO THE EVENING. I PLAN TO LEAVE THE PREVIOUS FORECAST
GOING, DIMINISHING POPS TO LESS THAN 14 PERCENT BY 10 PM CDT. SINCE
ANY OT THESE STORMS WILL LIKELY BE HIGH BASED, THE QPF AMOUNTS WILL
BE ON THE VERY LIGHT SIDE AROUND 0.01-INCH. AFTER WEDNESDAY NIGHT,
NO POPS WILL BE IN THE EXTENDED FORECAST, AND ALL MEDIUM RANGE
MODELS SUPPORT THIS DRY FORECAST.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1211 AM CDT WED JUL 18 2012
VARIABLE WINDS CAN BE EXPECTED OVER THE NEXT SEVERAL HOURS AS
SEVERAL OUTFLOW BOUNDARIES CROSS WESTERN KANSAS. AFTER 9Z THE
WINDS ARE EXPECTED TO BECOME SOUTH AGAIN AT AROUND 10KTS. ONLY MID
LEVEL MOISTURE WILL ACCOMPANY AN UPPER LEVEL DISTURBANCE AS IT
CROSSES WESTERN KANSAS EARLY THIS MORNING. IN ADDITION A FEW
WIDELY SCATTERED SHOWERS WILL BE POSSIBLE IN THE HAYS AREA THROUGH
08Z. AFTER 12Z A TROUGH OF LOW PRESSURE WILL SLOWLY MOVE EAST
ACROSS WESTERN KANSAS AND BY 21Z THIS BOUNDARY IS EXPECTED TO
EXTEND FROM NEAR HAYS TO GARDEN CITY. ALONG THIS BOUNDARY WIDELY
SCATTERED THUNDERSTORMS WILL BE POSSIBLE LATE THIS AFTERNOON AND
EARLY THIS EVENING...ESPECIALLY IN NORTH CENTRAL KANSAS NEAR HAYS
BETWEEN 21Z AND 03Z.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 101 72 102 74 / 20 20 0 0
GCK 100 69 101 73 / 20 20 0 0
EHA 98 70 100 72 / 10 20 0 0
LBL 101 69 101 73 / 10 20 0 0
HYS 104 73 105 76 / 20 20 0 10
P28 104 73 103 77 / 0 10 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BURGERT
SHORT TERM...BURGERT
LONG TERM...BURKE
AVIATION...BURGERT
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1206 AM EDT WED JUL 18 2012
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 343 PM EDT TUE JUL 17 2012
COLD FRONT IS WELL TO THE SOUTH OF UPPER MICHIGAN AS PORTIONS OF
SOUTHERN WICSONSIN AND LOWER MICHIGAN CONTINUE TO BAKE. YET...DRY
DAY THAT WAS SUPPOSED TO BE OVER MOST OF THE AREA HAS HAD TOUGH TIME
TAKING SHAPE. MAIN CULPRIT FOR THE SHRA CURRENTLY ROAMING CNTRL UPR
MICHIGAN SEEMS TO HAVE BEEN A SUBTLE H6-H5 JET STREAK ALONG WITH
RIBBON OF LINGERING HIGHER H7 DWPNTS ACROSS THE AREA. ADDITIONAL
LIFT IS PROVIDED BY A WEAK SHORTWAVE NOW PUSHING INTO WESTERN LK
SUPERIOR. BULK OF ANY TSRA HAVE STAYED OVR NORTHERN WISCONSIN ALONG
NORTH EDGE OF 1-6KM MUCAPE GRADIENT. SHRA IN THE NORTH HAVE NOT
BEEN ALL THAT HEAVY...WITH ONLY A FEW HUNDREDTHS OBSERVED AT RAIN
GAGES OVR WESTERN UPR MICHIGAN THIS AFTN. EXPECT ALL THE MENTIONED
FORCING MECHANISMS TO DRIFT SOUTH OUT OF THE AREA EARLY THIS EVENING
AND HAVE PUT AN END TO POPS AT THAT TIME. RAPID REFRESH RUC MODEL
/HRRR/ WHICH DID NOT DO WELL SHOWING THE SHRA/TSRA FOR MUCH OF THE
MORNING FINALLY CAUGHT ON BY EARLY THIS AFTN...AND FCSTS A SIMILAR
FATE TO PRECIP THIS EVENING.
CLEARING SKIES THEN EXPECTED FM NORTHWEST TO SOUTHEAST THROUGH THE
EVENING. THINK THE CLEARING COULD LEAD TO FOG OVERNIGHT TONIGHT
THROUGH EARLY WEDNESDAY MORNING. PLUSES FOR FOG FORMATION ARE ADDED
SFC MOISTURE FROM THE RAIN TODAY/MINIMAL MIXING OR DRYING TODAY
ALONG WITH FAIRLY LIGHT WINDS/COOLING TEMPS. BEST CHANCE FOR FOG
WILL BE OVER WEST HALF AND ALSO WHERE NORTHEAST WINDS UPSLOPE
/HIGHER TERRAIN OF WEST AND NORTH CENTRAL/. LOOKS LIKE AM ON MY
OWN ON THIS ONE THOUGH AS NO GUIDANCE HAS REALLY ANY HINT OF FOG
TONIGHT. GIVEN THOSE SIGNALS...IT IS TOUGH TO GO WITH ANYTHING MORE
THAN PATCHY FOG AT THIS POINT.
IF ANY FOG/STRATUS DEVELOPS TONIGHT IT WILL DEPART SHORTLY AFTER
SUNRISE ON WEDNESDAY MORNING SINCE IT WILL SFC BASED/SHALLOW. WITH
MAINLY SUNNY SKIES FOR THE AFTN HIGH TEMPS SHOULD RISE WELL INTO
THE 70S MOST AREAS WITH EVEN SOME LOWER 80S POSSIBLE TOWARD THE
WISCONSIN BORDER. DAYTIME MIXING WILL RESULT IN LESS HUMID
CONDITIONS.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 343 PM EDT TUE JUL 17 2012
AREA WILL BE BETWEEN TWO UPPER TROUGHS ON WED NIGHT...ONE OVER
QUEBEC AND THE OTHER OVER THE PAC NW. THIS WILL LEAD TO A RIDGE
OVER THE NRN PLAINS AND CANADIAN PRAIRIES THAT WILL TRY TO PUSH
EAST TOWARDS THE CWA...BUT WILL BE HELD OFF REINFORCING NRN STREAM
WAVES ATTEMPTING TO KEEP THE UPPER TORUGH OVER QUEBEC. THIS WILL
PUT THE CWA ON THE EDGE OF THE WARM TEMPS THIS WEEKEND...UNTIL THE
UPPER RIDGE FINALLY MOVES OVERHEAD DURING THE BEGINNING OF NEXT
WEEK.
CANADIAN HIGH PRESSURE RIDGE WILL BE OVER UPPER MI ON WED NIGHT AND
THEN GRADUALLY SHIFT SOUTHEAST THROUGH THE REST OF THE WORK WEEK AS
THE TROUGH OVER QUEBEC MOVES INTO THE NEW ENGLAND STATES. MODELS
CONSISTENT ON A SHORTWAVE SLIDING THROUGH THE FLOW ON WED NIGHT INTO
THURS...BUT VARY CONSIDERABLY ON THE LOCATION/INTENSITY. ECMWF IS
THE FARTHEST N AND STRONGEST WITH THE LLVL WAA OVER NRN WI...WHILE
THE REST OF THE MODELS ARE MUCH WEAKER WITH THE WAA AND FARTHER SW.
DRY AIR DOES TRY TO BREAK DOWN THE MOISTURE IN THE MID LVLS OVER THE
SW HALF OF THE CWA WED NIGHT INTO THURS MORNING...BEFORE DIMINISHING
IN THE AFTN. LLVL DRY AIR WILL LIKELY KEEP IT MID CLOUDS AND WITH
THE BEST FORCING LIKELY STAYING TO THE S...WANTED TO KEEP POPS
IN NRN WI. BUT WITH 12Z ECMWF CONTINUING TO SHOW PCPN MAKING IT
INTO UPPER MI...WILL CONTINUE MENTION SLIGHT CHANCES JUST OVER
THE WI BORDER.
OTHERWISE...HIGH PRESSURE RIDGE AND DRY CANADIAN AIR WILL KEEP THE
AREA MOSTLY/PARTLY CLEAR INTO FRI. TEMPS WILL BE SLIGHTLY ABOVE
NORMAL ON THURS AND THEN WARM SLIGHTLY ON FRI...AS WARM AIR ALOFT
STARTS TO WORK E AND BACK OVER THE CWA.
NRN STREAM WAVE SLIDING THROUGH CNTRL CANADA FRI NIGHT AND INTO NRN
ONTARIO WILL TRY TO PUSH A COLD FRONT TOWARDS THE AREA ON SAT INTO
SUN. IT ACTUALLY MOVES INTO NRN MN ON FRI...BUT STALLS AS IT
RUNS INTO THE SFC HIGH OVER UPPER MI. WITH IT BEING A GOOD WAYS AWAY
FROM IT/S SOURCE...AND LIMITED CONVERGENCE...EXPECT PCPN TO BE
SCATTERED ALONG THE FRONT. THUS...WILL CONTINUE TO MENTION SLIGHT
AND LOW CHANCE POPS FRI NIGHT INTO SUN. FRONT FINALLY SLIDES S OF
THE AREA ON SUN NIGHT AND WILL END PCPN CHANCE AT THAT POINT.
UPPER RIDGE THEN REALLY BUILDS IN MON/TUES AS ANOTHER CANADIAN HIGH
PRESSURE RIDGE SLIDES INTO THE AREA. THERE ARE A FEW
WEAK SHORTWAVES TRYING TO ROUND THE RIDGE...BUT WITH LITTLE
TO NO INSTABILITY...WILL KEEP THE FORECAST DRY FOR MON AND
MON NIGHT. ANOTHER COLD FRONT WILL LIKELY APPROACH THE UPPER GREAT
LAKES LATE TUES AFTN AND INTO WED...SO HAVE BROUGHT IN CHANCES
OVER THE WEST. HIGHS ARE STILL EXPECTED TO BE ABOVE NORMAL THROUGH
THE PERIOD...IN THE 80S AND LOW 90S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1206 AM EDT WED JUL 18 2012
THERE IS SOME CONCERN THAT FOG MAY DEVELOP TONIGHT AFTER ADDED
MOISTURE FROM LIGHT SHOWERS TODAY AND AS NIGHTTIME COOLING LEADS
TO BASED INVERSION. THE BEST CHANCE FOR FOG WILL BE AT KSAW WITH
IDEAL UPSLOPE LOW-LEVELS WIND FCST. PATCHY GROUND FOG MAY ALSO
AFFECT KIWD. HOWEVER...CONFIDENCE IS LOW GIVEN SLOW INFLUX OF DRIER
AIR INTO THE REGION WITH WEAK LOW LEVEL ACYC FLOW. A PERIOD OF MID
CLOUDS WILL ALSO LIMIT RADIATIONAL COOLING AT KCMX. VFR CONDITIONS
ARE EXPECTED AFTER ANY LOW CLOUDS/FOG DIMINISH WEDNESDAY MORNING.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 343 PM EDT TUE JUL 17 2012
HIGH PRES BUILDING S TOWARD THE UPPER LAKES WILL ARRIVE IN FULL
FORCE LATE TONIGHT INTO WEDNESDAY. THE HIGH WILL REMAIN OVERHEAD
THROUGH THE UPCOMING WEEKEND...SO WINDS WILL BE ON THE LIGHT SIDE...
MAINLY LESS THAN 15 KTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLA
LONG TERM...SRF
AVIATION...JLB
MARINE...JLA
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
634 PM CDT THU JUL 19 2012
.SHORT TERM...
ISSUED AT 325 PM CDT THU JUL 19 2012
(TONIGHT)
`COLD` FRONT IS DRIFTING THROUGH THE NORTHERN PORTION OF THE CWFA
THIS AFTERNOON. SHORT-RANGE EXPLICIT MODELS SUCH AS THE HRRR... AND
NCEP 4KM WRF FIRE UP CONVECTION SOUTH OF THE STL METRO AREA ACROSS
THE EASTERN OZARKS WHERE LOW LEVEL CONVERGENCE IS MAXIMIZED ALONG A
PRE-FRONTAL TROF. WHILE THE RAP AND NAM DO HAVE SOME PRECIP AS FAR
NORTH AS THE I-70 CORRIDOR...I THINK ANY PRECIP THAT BREAKS OUT THAT
FAR NORTH WILL BE SPOTTY AND WEAK. PRECIP ACROSS THE OZARKS SHOULD
END BY LATE EVENING.
(FRIDAY-SATURDAY)
SOMEWHAT COOLER AIR WILL FILTER INTO EASTERN MISSOURI AND SOUTHERN
ILLINOIS FOR FRIDAY AND SATURDAY. MODELS ARE IN GOOD AGREEMENT THAT
850MB TEMPS WILL DROP DOWN TO THE 20-22C RANGE WHICH MIXES DOWN TO
THE LOW TO MID 90S. HAVE BASICALLY IGNORED THE COOL GFS GUIDANCE
AND STUCK VERY CLOSE TO PERSISTENCE AND THE NAM. SHOULD BE ABLE TO
KEEP HEAT INDEX VALUES BELOW 100 DEGREES BOTH DAYS...SO WILL LET THE
ADVISORY EXPIRE AS PLANNED.
CARNEY
&&
.LONG TERM...
ISSUED AT 325 PM CDT THU JUL 19 2012
(SUNDAY-THURSDAY)
MEDIUM RANGE GUIDANCE HAS BEEN VERY PERSISTENT IN BUILDING THE UPPER
LEVEL RIDGE BACK OVER THE AREA ON SUNDAY AND KEEPING IT OVER US
THROUGH MID-WEEK. 850MB TEMPS ON THE ECMWF RISE TO 24C-26C OVER THE
AREA AS THE THERMAL RIDGE BUILDS BACK OVER THE MIDWEST WITH A
VENGEANCE. EXPECT TEMPERATURES AOA 100 DEGREES FOR THE ENTIRE WEEK
WITH HEAT INDEX VALUES IN EXCESS OF 105. HEAT INDEX VALUES MAY BE A
BIT LOWER OVER THE EASTERN OZARKS DUE TO SLIGHTLY LOWER AMBIENT
TEMPERATURES AND LOWER DEWPOINTS SINCE THEY WILL BE FURTHEST FROM
THE THERMAL RIDGE AXIS. HAVE ISSUED AN EXCESSIVE HEAT WATCH FOR
MOST OF EASTERN MISSOURI AND SOUTHWEST ILLINOIS...BUT LEFT THE
EASTERN OZARKS OUT. MODELS TRY TO PRINT OUT SOME SPOTTY PRECIP HERE
AND THERE DURING THE AFTERNOON...BUT HAVE KEPT THE EXTENDED DRY DUE
TO THE PERSISTENT DROUGHT.
CARNEY
&&
.AVIATION...
ISSUED AT 634 PM CDT THU JUL 19 2012
ISOLD -SHRA/-TSRA HAVE DEVELOPED THE LAST FEW HOURS FROM JUST WEST KSUS INTO
SOUTH CENTRAL ILLINOIS ALONG A WEAK FRONT THAT IS MOVING SOUTH ACROSS
THE AREA. THESE ARE DYING OUT FAIRLY QUICKLY...SO HAVE LEFT OUT ANY
MENTION AT THE ST. LOUIS METRO TAF SITES. OTHERWISE DRY AND VFR CONDITIONS
ARE EXPECTED. NORTHWEST WINDS WILL SHIFT OUT OF THE NORTH BEHIND
THE AFOREMENTIONED BOUNDARY.
SPECIFICS FOR KSTL...DRY AND VFR CONDITIONS ARE EXPECT THE NEXT 30
HOURS. CURRENT NORTHWEST WINDS WILL SHIFT OUT OF THE NORTH BY 01Z.
BRITT
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR AUDRAIN MO-BOONE
MO-CALLAWAY MO-COLE MO-CRAWFORD MO-FRANKLIN MO-GASCONADE MO-
IRON MO-JEFFERSON MO-KNOX MO-LEWIS MO-LINCOLN MO-MADISON MO-
MARION MO-MONITEAU MO-MONROE MO-MONTGOMERY MO-OSAGE MO-PIKE
MO-RALLS MO-REYNOLDS MO-SHELBY MO-ST. CHARLES MO-ST.
FRANCOIS MO-ST. LOUIS CITY MO-ST. LOUIS MO-STE. GENEVIEVE
MO-WARREN MO-WASHINGTON MO.
EXCESSIVE HEAT WATCH FROM SUNDAY AFTERNOON THROUGH THURSDAY
EVENING FOR AUDRAIN MO-BOONE MO-CALLAWAY MO-COLE MO-
FRANKLIN MO-GASCONADE MO-JEFFERSON MO-KNOX MO-LEWIS MO-
LINCOLN MO-MARION MO-MONITEAU MO-MONROE MO-MONTGOMERY MO-
OSAGE MO-PIKE MO-RALLS MO-SHELBY MO-ST. CHARLES MO-ST.
LOUIS CITY MO-ST. LOUIS MO-WARREN MO.
IL...HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR ADAMS IL-BOND IL-
BROWN IL-CALHOUN IL-CLINTON IL-FAYETTE IL-GREENE IL-JERSEY
IL-MACOUPIN IL-MADISON IL-MARION IL-MONROE IL-MONTGOMERY IL-
PIKE IL-RANDOLPH IL-ST. CLAIR IL-WASHINGTON IL.
EXCESSIVE HEAT WATCH FROM SUNDAY AFTERNOON THROUGH THURSDAY
EVENING FOR ADAMS IL-BOND IL-BROWN IL-CALHOUN IL-CLINTON IL-
FAYETTE IL-GREENE IL-JERSEY IL-MACOUPIN IL-MADISON IL-
MARION IL-MONROE IL-MONTGOMERY IL-PIKE IL-ST. CLAIR IL-
WASHINGTON IL.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
327 PM CDT THU JUL 19 2012
.SHORT TERM...
ISSUED AT 325 PM CDT THU JUL 19 2012
(TONIGHT)
`COLD` FRONT IS DRIFTING THROUGH THE NORTHERN PORTION OF THE CWFA
THIS AFTERNOON. SHORT-RANGE EXPLICIT MODELS SUCH AS THE HRRR... AND
NCEP 4KM WRF FIRE UP CONVECTION SOUTH OF THE STL METRO AREA ACROSS
THE EASTERN OZARKS WHERE LOW LEVEL CONVERGENCE IS MAXIMIZED ALONG A
PRE-FRONTAL TROF. WHILE THE RAP AND NAM DO HAVE SOME PRECIP AS FAR
NORTH AS THE I-70 CORRIDOR...I THINK ANY PRECIP THAT BREAKS OUT THAT
FAR NORTH WILL BE SPOTTY AND WEAK. PRECIP ACROSS THE OZARKS SHOULD
END BY LATE EVENING.
(FRIDAY-SATURDAY)
SOMEWHAT COOLER AIR WILL FILTER INTO EASTERN MISSOURI AND SOUTHERN
ILLINOIS FOR FRIDAY AND SATURDAY. MODELS ARE IN GOOD AGREEMENT THAT
850MB TEMPS WILL DROP DOWN TO THE 20-22C RANGE WHICH MIXES DOWN TO
THE LOW TO MID 90S. HAVE BASICALLY IGNORED THE COOL GFS GUIDANCE
AND STUCK VERY CLOSE TO PERSISTENCE AND THE NAM. SHOULD BE ABLE TO
KEEP HEAT INDEX VALUES BELOW 100 DEGREES BOTH DAYS...SO WILL LET THE
ADVISORY EXPIRE AS PLANNED.
CARNEY
&&
.LONG TERM...
ISSUED AT 325 PM CDT THU JUL 19 2012
(SUNDAY-THURSDAY)
MEDIUM RANGE GUIDANCE HAS BEEN VERY PERSISTENT IN BUILDING THE UPPER
LEVEL RIDGE BACK OVER THE AREA ON SUNDAY AND KEEPING IT OVER US
THROUGH MID-WEEK. 850MB TEMPS ON THE ECMWF RISE TO 24C-26C OVER THE
AREA AS THE THERMAL RIDGE BUILDS BACK OVER THE MIDWEST WITH A
VENGEANCE. EXPECT TEMPERATURES AOA 100 DEGREES FOR THE ENTIRE WEEK
WITH HEAT INDEX VALUES IN EXCESS OF 105. HEAT INDEX VALUES MAY BE A
BIT LOWER OVER THE EASTERN OZARKS DUE TO SLIGHTLY LOWER AMBIENT
TEMPERATURES AND LOWER DEWPOINTS SINCE THEY WILL BE FURTHEST FROM
THE THERMAL RIDGE AXIS. HAVE ISSUED AN EXCESSIVE HEAT WATCH FOR
MOST OF EASTERN MISSOURI AND SOUTHWEST ILLINOIS...BUT LEFT THE
EASTERN OZARKS OUT. MODELS TRY TO PRINT OUT SOME SPOTTY PRECIP HERE
AND THERE DURING THE AFTERNOON...BUT HAVE KEPT THE EXTENDED DRY DUE
TO THE PERSISTENT DROUGHT.
CARNEY
&&
.AVIATION...
ISSUED AT 1233 PM CDT THU JUL 19 2012
PREFRONTAL BAND OF MID CLOUD AND ISOLATED SHOWERS CONTINUES TO SAG
SOUTH OF THE TERMINALS. COLD FRONT THROUGH KUIN...SHIFTING WIND TO
THE NORTHWEST. EXPECT COLD FRONT WILL CONTINUE TO MARCH SOUTH THIS
AFTERNOON WITH WIND SHIFTING TO THE NORTHWEST AT ALL TERMINALS BY
00Z. PROSPECTS OF PRECIPITATION ARE LOW AND FORECAST REMAINS DRY.
VFR CONDITIONS EXPECTED TONIGHT AND FRIDAY WITH A 5 TO 10 KT NORTH
TO NORTHEAST WIND.
SPECIFICS FOR KSTL...
PREFRONTAL BAND OF MID CLOUDS WILL CONTINUE TO MOVE SOUTH OF THE
TERMINAL. WILL LIKELY SEE SOME CU DEVELOP AROUND 8KFT. NOT TOO
EXCITED ABOUT CONVECTION DEVELOPING GIVEN WEAK CONVERGENCE WITH
THE COLD FRONT. WIND TO SHIFT TO THE NORTHWEST BY 21Z AND VEER
AROUND TO THE NORTHEAST ON FRIDAY.
CVKING
&&
.PRELIMINARY POINT TEMPS/POPS...
ST LOUIS 75 95 75 96 / 10 5 0 0
QUINCY 70 92 69 96 / 10 0 0 0
COLUMBIA 74 96 72 98 / 10 5 0 0
JEFFERSON CITY 74 96 72 99 / 10 5 0 0
SALEM 73 93 70 94 / 20 10 0 0
FARMINGTON 72 94 69 93 / 30 10 0 0
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR AUDRAIN MO-BOONE
MO-CALLAWAY MO-COLE MO-CRAWFORD MO-FRANKLIN MO-GASCONADE MO-
IRON MO-JEFFERSON MO-KNOX MO-LEWIS MO-LINCOLN MO-MADISON MO-
MARION MO-MONITEAU MO-MONROE MO-MONTGOMERY MO-OSAGE MO-PIKE
MO-RALLS MO-REYNOLDS MO-SHELBY MO-ST. CHARLES MO-ST.
FRANCOIS MO-ST. LOUIS CITY MO-ST. LOUIS MO-STE. GENEVIEVE
MO-WARREN MO-WASHINGTON MO.
EXCESSIVE HEAT WATCH FROM SUNDAY AFTERNOON THROUGH THURSDAY
EVENING FOR AUDRAIN MO-BOONE MO-CALLAWAY MO-COLE MO-
FRANKLIN MO-GASCONADE MO-JEFFERSON MO-KNOX MO-LEWIS MO-
LINCOLN MO-MARION MO-MONITEAU MO-MONROE MO-MONTGOMERY MO-
OSAGE MO-PIKE MO-RALLS MO-SHELBY MO-ST. CHARLES MO-ST.
LOUIS CITY MO-ST. LOUIS MO-WARREN MO.
IL...HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR ADAMS IL-BOND IL-
BROWN IL-CALHOUN IL-CLINTON IL-FAYETTE IL-GREENE IL-JERSEY
IL-MACOUPIN IL-MADISON IL-MARION IL-MONROE IL-MONTGOMERY IL-
PIKE IL-RANDOLPH IL-ST. CLAIR IL-WASHINGTON IL.
EXCESSIVE HEAT WATCH FROM SUNDAY AFTERNOON THROUGH THURSDAY
EVENING FOR ADAMS IL-BOND IL-BROWN IL-CALHOUN IL-CLINTON IL-
FAYETTE IL-GREENE IL-JERSEY IL-MACOUPIN IL-MADISON IL-
MARION IL-MONROE IL-MONTGOMERY IL-PIKE IL-ST. CLAIR IL-
WASHINGTON IL.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS HASTINGS NE
407 PM CDT WED JUL 18 2012
.SHORT TERM...TODAY THROUGH THURSDAY. WILL KEEP THE VERY SLIGHT
CHANCES OF SHOWERS AND THUNDERSTORMS IN THE FORECAST THROUGH EARLY
EVENING. THIS IS ONLY A 20 PERCENT CHANCE OF PRECIPITATION. VERY HOT
WEATHER WILL CONTINUE THROUGHOUT THE PERIOD.
VISIBLE SATELLITE IMAGERY DEPICTS AN EXPANDING CU FIELD WITH
DEVELOPING THUNDERSTORMS ACROSS WESTERN NEBRASKA. MOST OF THESE
STORMS WILL DIE PRIOR TO MAKING IT INTO OR CWA. HOWEVER...THERE IS A
SLIGHT CHANCE THAT A FEW OF THESE THUNDERSTORMS MIGHT MAKE IT AS
FAR EAST AS OUR FAR WESTERN ZONES BEFORE DIEING OUT. IT IS HARD TO
PICK OUT BOUNDARIES ON THE SFC MAP WITH THE SFC WINDS BEING VERY
LIGHT AND VARIABLE ACROSS MOST OF OUR CWA. THERE IS A SLIGHTLY
MORE DEFINED SFC BOUNDARY OVER NORTH CENTRAL KANSAS WITH SOUTH
SOUTHWEST WINDS SOUTH OF THE FRONT AND NORTHEAST WINDS NORTH OF
THE FRONT. THE HRRR AND 4KM WRF CONTINUE TO HINT AT THE
POSSIBILITY OF A FEW ISOLATED THUNDERSTORMS OVER OUR CWA EARLY
THIS AFTERNOON. WE HAVE BEEN SEEING A FEW OFF AND ON SHOWERS
ACROSS THE AREA THIS AFTERNOON AND BELIEVE THIS COULD CONTINUE
UNTIL WE LOSE DIURNAL HEATING LATER THIS EVENING.
THE UPPER RIDGE WILL CONTINUE TO BUILD ON THURSDAY AND THIS SHOULD
SHUT DOWN ALL PRECIPITATION CHANCES FOR AWHILE. THEREFORE...EXPECT
DRY CONDITIONS ON THURSDAY AND IT WILL CONTINUE TO BE VERY HOT.
HEAT INDEX VALUES ARE NOT HIGH ENOUGH YET TO PUT NORTHERN ZONES IN
THE HEAT ADVISORY...BUT SOUTHERN ZONES SHOULD ONCE AGAIN SEE
TEMPERATURES/HEAT INDEX VALUES OF 100 TO 105 DEGREES.
.LONG TERM...THURSDAY NIGHT THROUGH WEDNESDAY. MAIN FORECAST
CONCERNS WILL BE HOT TEMPERATURES AND A CHANCE FOR SOME
THUNDERSTORMS ON WEDNESDAY.
THE UPPER LEVEL RIDGE THAT HAS BEEN THE MAINSTAY ACROSS THE PLAINS
FOR SEVERAL DAYS WILL CONTINUE TO PLAGUE THE FORECAST AREA THROUGH
TUESDAY. TEMPERATURES WILL TOP OUT AROUND 10 DEGREES ABOVE NORMAL.
IN ADDITION TO THE HEAT THE HUMIDITY WILL ALSO CAUSE HEAT INDEX
VALUES TO RISE TO 100 TO 105 FOR NORTH CENTRAL KANSAS AND FAR
SOUTHERN NEBRASKA FOR SATURDAY INTO SUNDAY. THE HEAT CONTINUES
ACROSS THE ENTIRE AREA FOR MONDAY AND TUESDAY...WITH HIGH
TEMPERATURES ACROSS THE AREA EXPECTED TO BE AT OR ABOVE 100 DEGREES.
THERE IS A POTENTIAL FOR A BREAK IN THE HEAT MID WEEK NEXT WEEK. THE
UPPER LEVEL RIDGE FINALLY BREAKS DOWN AS AN UPPER LEVEL WAVE MOVES
THROUGH THE NORTHERN PLAINS. MODELS STILL HAVE SOME DIFFERENCES IN
TIMING AND LOCATION OF THE UPPER WAVE AND THE SURFACE FRONT THAT IS
EXPECTED TO MOVE THROUGH THE AREA. THE GFS IS A LITTLE SLOWER WITH
THE SURFACE FRONT AND A LITTLE FURTHER SOUTH WITH THE UPPER WAVE
THAN THE ECMWF. WILL GO MORE WITH THE SLOWER SOLUTION SINCE THAT IS
TYPICAL OF THE MODELS TO MOVE THINGS THROUGH TOO QUICKLY. WILL HAVE
A CHANCE FOR SOME THUNDERSTORMS IN THE WEST FOR WEDNESDAY AND
TEMPERATURES SHOULD BE A BIT COOLER WITH READINGS ONLY IN THE 90S.
&&
.AVIATION...18Z KGRI TAF. A WEAK SFC FRONTAL BOUNDARY HAS STALLED
ACROSS SOUTH CENTRAL NEBRASKA...AND THE BOUNDARY MAY TRIGGER A FEW
SHOWERS AND THUNDERSTORMS LATER THIS AFTERNOON. HOWEVER...THIS
ACTIVITY IS EXPECTED TO BE ISOLATED AND HAS NOT BEEN INCLUDED FOR
THE TERMINAL DUE TO THE LIMITED COVERAGE. WITH THE MEANDERING
BOUNDARY RIGHT OVERHEAD...WINDS WILL BE LIGHT AND VARIABLE THROUGH
TONIGHT. THE WIND WILL BECOME MORE EASTERLY TOMORROW. CLEAR TO
SCATTERED CLOUD COVER IS EXPECTED WITH A CONTINUATION OF VFR
CONDITIONS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...HEAT ADVISORY UNTIL 8 PM CDT SUNDAY FOR NEZ082>087.
KS...HEAT ADVISORY UNTIL 8 PM CDT SUNDAY FOR KSZ005>007-017>019.
&&
$$
AREA FORECAST DISCUSSION
NWS BUFFALO NY
1021 AM EDT WED JUL 18 2012
.SYNOPSIS...
A COLD FRONT LOCATED JUST SOUTH OF NEW YORK STATE WILL CONTINUE TO
TO DRIFT SLOWLY TO THE SOUTH THIS AFTERNOON. SOMEWHAT MOIST AND
UNSTABLE AIR LINGERING NORTH OF THE FRONT WILL BRING SCATTERED
SHOWERS AND THUNDERSTORMS TO THE SOUTHERN TIER AND UPPER GENESEE
VALLEY...WHILE AREAS TO THE NORTH SEE SOME INCREASE IN SUNSHINE.
CANADIAN HIGH PRESSURE WILL BRING A WELCOME CHANGE TO COOLER AND
LESS HUMID CONDITIONS TONIGHT THROUGH THE END OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
THE LATEST SURFACE MAP SHOWS THE COLD FRONT SITUATED JUST SOUTH OF
THE NEW YORK/PA BORDER. THE MOIST NORTHERLY FLOW LINGERING BEHIND
THE FRONT IS GENERATING A FAIR AMOUNT OF CLOUDS SOUTH OF LAKE
ONTARIO...BUT AS SOMEWHAT DRIER AIR ADVECTS SOUTH OF THE LAKE THIS
AFTERNOON...EXPECT TO SEE A GRADUAL NORTH TO SOUTH DECREASE IN
CLOUDS. THE EXCEPTION TO THIS GENERAL TREND WILL BE ACROSS THE
SOUTHERN TIER AND PARTS OF THE UPPER GENESEE VALLEY WHERE THE RISK
FOR CONVECTION WILL CONTINUE TODAY. THE MAIN CULPRIT IS AN AREA OF
FAVORABLE LOW LEVEL MOISTURE CONVERGENCE AND INSTABILITY CENTERED
ALONG AN ELEVATED FRONT THAT STRETCHES FROM CENTRAL MICHIGAN TO LAKE
ERIE. THE LATEST GUIDANCE SUGGESTS THAT THE EASTERN END OF THIS
ELEVATED INSTABILITY AXIS WILL WORKS INTO THE SOUTHERN TIER LATER
THIS MORNING AND REMAIN IN PLACE THROUGH A GOOD PART OF THE
AFTERNOON. BASED ON THE LATEST RADAR TRENDS...THE CONVECTION THAT IS
CURRENTLY OVER EASTERN LAKE ERIE WILL BE ADVECTING ACROSS
CHAUTAUQUA COUNTY BY LATE MORNING. AFTER THAT...EXPECT SCATTERED
SHOWERS/THUNDERSTORMS TO SPREAD MORE TO THE EAST AND POSSIBLY IMPACT
PARTS OF THE UPPER GENESEE VALLEY...A TREND THE LATEST HRRR PICKS UP
ON. IN TERMS OF THE STRENGTH OF THE CONVECTION...IT STILL LOOKS
LIKE THE MOST UNSTABLE AIR WILL REMAIN SOUTH OF THE NEW YORK BORDER
EVEN THOUGH THE MORE FAVORABLE EFFECTIVE SHEAR WILL BE IN PLACE OVER
OUR CWA. BASED ON THESE TRENDS...WILL KEEP THE HIGHEST CHANCE POPS
FOR MEASURABLE PCPN OVER THE SOUTHERN TIER.
TEMPERATURES TODAY WILL BE A BIT COOLER THAN THE HOT AND HUMID
CONDITIONS OBSERVED ON TUESDAY...ALTHOUGH HUMIDITY LEVELS WILL STILL
BE IN THE UNCOMFORTABLE RANGE.
TONIGHT...CANADIAN HIGH PRESSURE CENTERED OVER THE HUDSON BAY WILL
BUILD IN BEHIND THE FRONT. EXPECTING CLEAR SKIES ACROSS MUCH OF THE
FORECAST AREA EXCEPT FOR MAYBE LINGERING CLOUDINESS ACROSS THE
SOUTHERN TIER FROM AFTERNOON STORMS. MUCH MORE COMFORTABLE SLEEPING
TEMPERATURES WILL OCCUR OVERNIGHT ALLOWING FOR THOSE AIR
CONDITIONERS TO TAKE A BREAK. TEMPS FALLING INTO THE LOW TO MID 60S
FOR WESTERN NY TO UPPER 50S ACROSS THE NORTH COUNTRY.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
CANADIAN HIGH PRESSURE CENTERED NEAR JAMES BAY WILL NOSE DOWN
ACROSS WESTERN AND CENTRAL NEW YORK THURSDAY...THEN GRADUALLY
SHIFT TO THE SOUTHEAST AS THE TROUGH OVER QUEBEC MOVES INTO THE
NEW ENGLAND STATES. PLENTY OF DRY AIR SUGGESTED ACROSS NORTHERN
SECTIONS FOR SUNNY/MOSTLY SUNNY FORECAST...WHILE A BIT MORE
MOISTURE ACROSS THE SOUTHERN HALF OF THE AREA IN CLOSER PROXIMITY
TO FRONTAL BOUNDARY LINGERING TO THE SOUTH AND WEST OF THE AREA.
NOTICEABLY COOLER DAY WITH HIGHS GENERALLY IN THE MID TO UPPER
70S.
00Z MODELS SIGNALS ARE SIMILAR WITH IMPLIED MESOSCALE
DETAILS/EVOLUTION UNCERTAIN...WITH RESPECT TO THE PLACEMENT OF
UPSTREAM CONVECTION ALONG WHAT SHOULD BE AN ACTIVE SURFACE
FRONTAL ZONE JUST OFF TO OUR SOUTH AND WEST THROUGH THE REST OF
THE SHORT TERM PERIOD. SOME MODEL SUGGESTION THAT CONVECTIVE
COMPLEXES WILL RIDE ALONG THE FRONTAL ZONE FROM THE SOUTHERN
GREAT LAKES THROUGH THE OHIO VALLEY...WITH THE NORTHERN EXTENT OF
THIS CONVECTION POTENTIALLY SHIFTING NORTHWARD INTO SOUTHERN
PORTIONS OF THE AREA. AT THIS TIME...PREFER TO GIVE MORE WEIGHT
TO A PERSISTENCE DRY FORECAST WITH THE CANADIAN HIGH SHIFTING
CONVECTIVE CHANCES OFF TO OUR SOUTH. SEASONABLE TEMPERATURES
REMAINING FRIDAY WITH MOST HIGHS IN THE UPPER 70S.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
THIS TIME PERIOD WILL LARGELY BE DRY...THOUGH A WEAK FRONTAL
BOUNDARY COULD BRING SOME SPOTTY SHOWERS AND THUNDERSTORMS TOWARDS
THE END OF THE WEEKEND/BEGINNING OF THE WORK WEEK. TEMPERATURES WILL
AVERAGE AROUND NORMAL FOR THE TIME PERIOD AND NO EXTREME HEAT
EXPECTED.
THE LARGE SCALE PATTERN FOR THIS TIME PERIOD PLACES A BROAD RIDGE OF
HIGH PRESSURE OVER THE CENTRAL US/ROCKIES WITH SHORT WAVE TROUGHS
ROUNDING THE RIDGE AND CROSSING THE EASTERN GREAT LAKES THROUGH THE
PERIOD.
FOR FRIDAY A GENERAL TROUGH WILL BE ACROSS NEW ENGLAND AND THE
EASTERN GREAT LAKES REGION. MOISTURE IS MARGINAL AND WITH PLENTY OF
DRY AIR IN THE LOW TO MID LEVELS BELOW THIS MOISTURE WILL MAINTAIN
THE DRY FORECAST WITH A MIX OF SUN AND CLOUDS. WITH THIS NORTHERLY
FLOW EXPECT AFTERNOON TEMPERATURES TO REMAIN BELOW NORMAL...WITH
COMFORTABLE SUMMER HIGHS IN THE MID TO UPPER 70S.
ON SATURDAY BOTH THE 12Z ECMWF AND GFS BRING A RIDGE ALOFT ACROSS
THE REGION BEHIND A SHORT WAVE THAT IS EXITING ACROSS NEW ENGLAND
AND OVER THE WESTERN ATLANTIC. WITH AMPLE DRY AIR EXPECT MOSTLY
SUNNY SKIES AND AFTERNOON TEMPERATURES SEVERAL DEGREES WARMER. AIR
TEMPERATURES OF LOW TO MID 80S WILL BE COMMON...AND THOUGH DEW
POINTS WILL BE RISING MOST AREAS SHOULD STAY BELOW 60...SO WE SHOULD
STILL REMAIN COMFORTABLE.
ON SUNDAY BOTH THE ECMWF AND GFS BRING THE CREST OF WARMTH ALOFT
ACROSS THE REGION WITH 850 HPA TEMPERATURES REACHING +15 TO +18C.
BEHIND THE UPPER LEVEL RIDGE CLOUDS WILL LIKELY INCREASE SOME AS
WELL...LEAVING TEMPERATURES SUNDAY SIMILAR TO SATURDAY. AN UPPER
LEVEL SHORT WAVE ACROSS SOUTHERN CANADA WILL CLIP/NEAR THE NORTH
COUNTRY SUNDAY WITH A SLIGHT CHANCE FOR A SHOWER OR ISOLATED
THUNDERSTORMS. THOUGH TEMPERATURES SUNDAY WILL BE SIMILAR TO
SATURDAY THE DEW POINT WILL BE HIGHER...WITH A MORE NOTICEABLE FEEL
OF HUMIDITY TO THE AIR. DEW POINTS WILL LIKELY CLIMB INTO THE 60S ON
SUNDAY.
ON MONDAY BOTH THE ECMWF AND GFS BRING A WEAK FRONTAL BOUNDARY
ACROSS THE REGION FROM THE NORTHERN GREAT LAKES. WITH THE BUILDING
MOISTURE AHEAD OF THIS FRONT A SHOWER OR THUNDERSTORM IS POSSIBLE
LATE SUNDAY NIGHT AND INTO MONDAY. GIVEN OUR DRY SPELL AND THE
WEAKNESS OF THIS FRONTAL BOUNDARY WILL JUST GO WITH LOW CHC POPS.
SOUTHWESTERLY WINDS AHEAD OF THIS FRONTAL BOUNDARY WILL MAINTAIN
SLIGHTLY WARMER THAN NORMAL TEMPERATURES FOR OUR REGION WITH
AFTERNOON HIGHS IN THE 80S
TUESDAY BOTH THE GFS AND ECMWF BRING DRIER AIR ACROSS THE REGION
WITH HIGH PRESSURE FOLLOWING THE WEAK FRONTAL BOUNDARY. SLIGHTLY
COOLER...BUT MORE NOTICEABLE LOWER DEWPOINTS ON TUESDAY WITH A
RETURN TO PLENTY OF SUNSHINE.
OVERNIGHT LOWS WILL GENERALLY FALL BACK INTO THE 60S...WITH THE
WARMEST NIGHT LIKELY SUNDAY NIGHT AHEAD OF THE WEAK COLD FRONT...AND
COOLEST MORNINGS FRIDAY AND SATURDAY WITH MAINLY CLEAR SKIES...LOW
DEW POINTS AND LIGHT WINDS.
&&
.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
EXPECT MAINLY VFR CONDITIONS...WITH KROC SEEING MVFR CIGS THIS
MORNING IN LOWER CLOUDS NORTH OF A COLD FRONT. ISOLATED SHOWERS AND
THUNDERSTORMS ARE POSSIBLE ACROSS WESTERN NY NEAR THE FRONT WITH
MORE SCATTERED ACTIVITY DEVELOPING ACROSS THE SOUTHERN TIER LATER
THIS AFTERNOON. ALL SITES WILL SEE CLEARING SKIES GOING INTO TONIGHT
AS HIGH PRESSURE BUILDS IN BEHIND THE FRONT. LAMP AND GFS MOS
GUIDANCE INDICATE POSSIBLE LOW VIS TONIGHT IN FOG AFTER 08Z.
INCLUDED 4SM FOR NOW IN THE TAF UNTIL CONFIDENCE INCREASES. IF KJHW
DOES PICK UP SOME RAIN FROM STORMS TODAY THEN FOG MORE LIKELY
TONIGHT.
OUTLOOK...
THURSDAY THROUGH SUNDAY...MAINLY VFR.
&&
.MARINE...
A COLD FRONT IS SOUTH OF LAKE ONTARIO ACROSS WESTERN NY TODAY WITH
SCATTERED TO SHOWERS AND THUNDERSTORMS OCCUR ACROSS LAKE ERIE THIS
AFTERNOON. BEHIND THE FRONT...HIGH PRESSURE WILL BUILD IN ACROSS NEW
YORK INTO THE WEEKEND AND CALM CONDITIONS WILL PREVAIL ACROSS BOTH
LAKES. NO SCA CONDITIONS EXPECTED.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...SMITH/TJP
NEAR TERM...SMITH/TJP
SHORT TERM...TMA
LONG TERM...THOMAS
AVIATION...SMITH
MARINE...SMITH
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
142 AM EDT WED JUL 18 2012
.SYNOPSIS...
AFTER A DAY OF RECORD OR NEAR RECORD HEAT...A COLD FRONT WILL SLIP
SOUTH TO TRIGGER SCATTERED THUNDERSTORMS ACROSS PORTIONS OF CENTRAL
NEW YORK TONIGHT...MAINLY ALONG THE NEW YORK THRUWAY REGION...SOME
OF WHICH COULD BE SEVERE. THE FRONT WILL CONTINUE TO PUSH SOUTH
FOR ADDITIONAL POSSIBLE SEVERE THUNDERSTORMS FOR MAINLY SOUTHERN
NEW YORK AND NORTHEAST PENNSYLVANIA WEDNESDAY. COOLER AND DRIER
AIR WILL BUILD IN BEHIND THE FRONT THURSDAY AND FRIDAY...FOLLOWED
BY WARMING TEMPERATURES OVER THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
1 AM UPDATE...
04Z SUBJECTIVE SURFACE ANALYSIS PLACES MAIN COLD FRONT ALONG A
HAMILTON, ON...TO TRENTON, ON...TO WATERTOWN LINE. AHEAD OF THIS
BOUNDARY OVERALL CONVECTIVE ACTIVITY HAS SHOWN A NOTICEABLE
WEAKENING TREND IN RECENT HRS AS MAIN MID-LEVEL FORCING REMAINS
WELL NORTH OF THE FCST AREA. EARLIER...RADAR TRENDS SHOWED RENEWED
CONVECTION JUST NORTH OF THE LAKE ONTARIO SHORE...HOWEVER NO NEW
DEVELOPMENT IS APPARENT WITHIN THE LAST HR OR SO. REGIONAL HIGH-
RES CONVECTION ALLOWING MODELS SUGGEST A CONTINUED WEAKENING TREND
OVERNIGHT AS MAIN COLD FRONT CONTINUES TO OUTRUN ANY MID-LEVEL
SUPPORT WHICH SHOULD JUST SKIRT NORTHERN PORTIONS OF OUR FCST
AREA. IN FACT...LATEST WATER VAPOR IMAGERY SHOWS A NICE SHORTWAVE
TROUGH LOCATED JUST NORTH OF LAKE HURON...WHICH IS JUST A BIT TOO
FAR NORTH TO HAVE ANY APPRECIABLE AFFECT ON CONVECTIVE TRENDS
ACROSS OUR REGION. THAT SAID...CONSIDERING RECENT RADAR TRENDS AND
GUIDANCE FROM REGIONAL HIGH-RES MODELS TO INCLUDE THE HRRR AND
WRF-ARW...HAVE ELECTED TO LOWER POPS FOR THE REMAINDER OF THE
MORNING HRS AS NOCTURNAL STABILIZATION PROCESSES CONTINUE. DESPITE
THIS...EXPECT THE FRONT TO GRADUALLY SINK THROUGH THE FINGER LAKES
INTO THE SOUTHERN TIER BY MORNING. AFTER 12Z...CONVECTION WILL
ONCE AGAIN DEVELOP ALONG THE BOUNDARY AS DAYTIME HEATING ONCE
AGAIN COMMENCES. WILL FURTHER INVESTIGATE SEVERE POTENTIAL PRIOR
TO THE NEXT UPDATE HOWEVER INITIAL IMPRESSIONS SUGGEST BEST
FORCING WILL AGAIN REMAIN NORTH OF THE AREA WHICH MAY INHIBIT
WIDESPREAD SEVERE COVERAGE.
10 PM UPDATE... CONVECTIVE COVERAGE HAS INCREASED A BIT SINCE
EARLIER THIS EVE ACRS UPSTATE NY...JUST S OF THE SFC FRNT...AND
ALG THE LEADING EDGE OF THE BETTER INSTAB (ML CAPES OF 1000-2000
ATTM STILL OVER MOST OF THE CWA). HOWEVER...THE STGR STORMS/DEEPER
CORES SEEM TO BE CLOSELY TIED TO A CONVERGENCE BNDRY NEAR THE S SHORE OF
LK ONT...WITH A GENERAL WEAKENING TREND NOTED SO FAR ONCE THEY
PUSH FARTHER INLAND.
AS THE SFC FRNT CONTS GRADUALLY SWD OVERNIGHT AND A WELL DEFINED
UPR-LVL WAVE COMES ACRS LK HURON/SRN ONT/FAR NRN NY...WE THINK AN
AREA OF SHRA/TSRA WILL SLOWLY PENETRATE FARTHER SWD ACRS CNY...AND
PERHAPS THE FAR NRN TIER OF PA TWDS DAYBREAK. IN
GENERAL...COVERAGE SHOULD LESSEN WITH SWD EXTENT...AS THE STORMS
OUTRUN THE BETTER FORCED ASCENT AND MORE PRONOUNCED DEEP-LYRD
SHEAR OFF TO THE N. OVERALL...THE SVR THREAT SEEMS MARGINAL...BUT
AN ISOLD STG/SVR STORM CAN`T BE RULED OUT...AND WE`LL CONTINUE TO
MONITOR DEVELOPMENTS.
PREV DISC... 7 PM UPDATE... CONDS REMAIN VERY QUIET ATTM
THROUGHOUT CNY/NE PA. THE AMS IS MODERATELY UNSTABLE (ML CAPES OF
1000-2000...AND LOCALLY HIGHER)...BUT LARGE-SCALE SUPPORT IS
LACKING. ACTIVE CONVECTION REMAINS CONFINED MUCH CLOSER TO THE SFC
FRNTL BNDRY...AND ALSO FORCING FROM A SERIES OF UPR-LVL
WAVES...FROM WI/NRN MI EWD THROUGH SRN ONT AND FAR UPSTATE NY.
AS THE NGT PROGRESSES...WE STILL EXPECT THAT THE SFC FRNT WILL CONTINUE
ITS SLOW SWD PUSH...AND ALSO THAT A WELL DEFINED UPR-LVL PV LOBE
WILL TRACK ESEWD FROM THE NRN LKS RGN TWDS UPSTATE NY AFTER 06Z.
ALTHOUGH AVAILABLE INSTABILITY SHOULD BE SOMEWHAT LESS BY
THEN...THERE WILL LIKELY BE ENOUGH OF IT (ML CAPES STILL NEAR OR
ABV 1000) TO INITIATE SOMEWHAT BETTER COVERAGE OF
SHRA/TSRA...GIVEN IMPROVED LIFT FROM JUST MENTIONED SYSTEMS.
POP/WX GRIDS WERE TWEAKED TO INDICATE ONLY ISOLD COVERAGE IN THE
FAR N THROUGH MUCH OF THE EVE (03-06Z)...WITH SCTD CONVECTION
COMING IN FROM WNW TO ESE IN THE 06-10Z TIME FRAME. OVERALL...WE
FEEL THE SVR THREAT IS SOMEWHAT LIMITED...BUT COMBINATION OF
LINGERING INSTAB...IMPROVING DEEP-LYRD SHEAR (0-6 KM VALUES OF
30-40 KT)...AND BETTER FORCED ASCENT COULD CONCEIVABLY TRIGGER A
FEW STG/SVR STORMS LATER TNT. WE`LL CONTINUE TO MONITOR.
JUST MINOR CHGS MADE TO NEAR-TERM TEMP/DEW PT GRIDS EARLY THIS EVE.
EARLIER DISC... 300 PM UPDATE... SEVERE THUNDERSTORM WATCH REMAINS IN
EFFECT UNTIL 9 PM FOR ONEIDA COUNTY...THOUGH IT WILL TAKE UNTIL
NEAR THE END OF THAT WATCH /PERHAPS EVEN AFTER/ FOR THE THREAT TO
PEAK. HEAT ADVISORY ALSO REMAINS IN EFFECT FOR THE LAKE PLAIN TO
MOHAWK VALLEY WHERE HEAT INDICES ARE NEAR OR SLIGHTLY ABOVE 100
DEGREES. ACTUAL TEMPERATURE IN SYRACUSE WITH DOWNSLOPING MANAGED
TO HIT 100 DEGREES SO FAR...EASILY SHATTERING THE DAILY
RECORD...AND GETTING ONLY 2 DEGREES FROM THE ALL TIME RECORD OF
102 SET JULY 9 1936.
FORECAST UPDATED FOR ANTICIPATED EVOLUTION OF CONVECTIVE
DEVELOPMENT...ESPECIALLY NY THRUWAY REGION...THOUGH DELAYED BY A
COUPLE HOURS DEEPER INTO THE EVENING FOR PEAK CHANCES. SURFACE
FRONT EXTENDS ROUGHLY ALONG THE ST. LAWRENCE VALLEY...THROUGH
ONTARIO /JUST NORTH OF LAKE ONTARIO/...BACK TO LAKE HURON AND
CENTRAL LOWER MICHIGAN. IT IS SET TO SAG SLOWLY SOUTH THROUGH
THE AREA LATE THIS EVENING THROUGH MIDDAY WEDNESDAY. SOUTH OF THE
FRONT...ATMOSPHERE WILL BE VERY WARM NOT JUST AT THE SURFACE BUT ALSO
MID LEVELS...INCLUDING 850 MB AT LEAST 23 DEG CELSIUS. THIS MID LEVEL
FOR NOW IS KEEPING CONVECTIVE INHIBITION OVER THE AREA. LATE EVENING
INTO TONIGHT...WE LOSE DIURNAL HEATING BUT CONDITIONS ALOFT BECOME
MORE FAVORABLE WITH WINDS AT UPPER LEVELS GOING FROM CONVERGENT TO
MORE NEUTRAL...AND MID LEVEL LAPSE RATES INCREASE. THE BIG QUESTION IS
WHETHER CONVECTION CAN INITIATE UPSTREAM /PERHAPS FROM THE WAVE
NOW IN UPPER WISCONSIN-NORTHERN MICHIGAN/...AND HOW FAR WILL IT
CARRY THROUGH THE AREA. THE ONE CERTAINTY HERE...IS THAT WITH
INVERTED-V IN THE LOW LEVELS...AND 35-50 KT OF SHEAR THROUGHOUT
THE 2KM-6KM LAYER...CONVECTION WILL BE CAPABLE OF STRONG
WINDS...WHILE LARGE HAIL AND ISOLATED TORNADOES ARE NOT AS LIKELY
BUT ALSO NOT OUT OF THE QUESTION.
BEST CHANCES WILL BE LATE THIS EVENING ACROSS THE NORTHERN
ZONES...ESPECIALLY ALONG AXIS OF THE NEW YORK THRUWAY...AND
PERHAPS EDGING FARTHER SOUTH TO AT LEAST FINGER LAKES-CATSKILLS
AXIS OVERNIGHT AS IT DIMINISHES WITH DECREASING INSTABILITY.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM THURSDAY/...
315 PM UPDATE...
STORM PREDICTION CENTER PLACES SOUTHERN TIER/CATSKILLS AND
NORTHEAST PENNSYLVANIA IN SLIGHT RISK FOR SEVERE WEATHER...WITH 30
PCT DAMAGING WIND RISK CONTOUR INCLUDING MUCH OF NORTHEAST PA.
UPPER DIVERGENCE COINCIDES WITH FRONTAL PASSAGE IN THE MORNING
HOURS...YET LOW LEVEL CONVERGENCE AND DIURNAL HEATING PEAK AS THE
FRONT IS HEADING OUT OF THE AREA. SHEAR IS NOT AS STRONG
WEDNESDAY...AS COMPARED TO THIS AFTERNOON/TONIGHT...BUT OVERALL
LOOKING QUITE ACTIVE FOR THE SOUTHERN HALF OF THE AREA LATE
MORNING INTO EARLY AFTERNOON. ALSO EXPECTING EARLIER INITIATION OF
CONVECTION BECAUSE OF FAVORABLE UPPER LEVEL SUPPORT.
LOWER ELEVATIONS IN THE SOUTHERN ZONES COULD STILL MANAGE 90
DEGREES WITH UNCOMFORTABLE UPPER 60S/NEAR 70 DEW POINTS...BUT
OTHERWISE TURNING COOLER CENTRAL AND NORTH...AS FRONT CONTINUES
TO SLIDE SOUTH...AND DEW POINTS DROP. ANY LINGERING CONVECTION
WEDNESDAY EVENING QUICKLY SHIFTS SOUTH. LOWS IN UPPER 50S NORTH TO
MID-UPPER 60S SOUTH BY DAWN THURSDAY.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
1 PM UPDATE...
COLD FRONT PUSHES SOUTHEAST THROUGH PA AND NJ THURSDAY WITH SURFACE
HIGH PRESSURE BUILDING INTO NY. UPPER LEVEL TROUGH IS OVER NEW
ENGLAND AND PULLING AWAY TO THE NORTHEAST. BY MIDDAY FRI A
SHORT-WAVE APPROACHES AND MAY HELP TO TRIGGER SOME SHOWERS ACROSS
THE POCONO AREA AND WYOMING VALLEY. WEAK RIDGING DURING THE DAY
SATURDAY WITH FAIR SKIES AND HIGHS IN THE MID 80S. WARM FRONT MOVES
THROUGH SATURDAY NIGHT WITH BRINGING SOME CLOUDS AND A CHANCE OF
TSTMS EAST OF LAKE ONTARIO INTO ONEIDA COUNTY. SUNDAY A COLD FRONT
AND UPPER LEVEL TROUGH APPROACH BRINGING A CHANCE FOR SHOWERS AND
THUNDERSTORMS IN THE AFTERNOON INTO MONDAY AS A WEAK COLD FRONT
MOVES SOUTHEAST ACROSS THE REGION. HIGH PRESSURE BUILDS IN TUESDAY.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
COLD FNT DROPPING THRU THE FCST AREA THIS MRNG. NIGHT TIME AIR IS
STABILIZING THE SNDG DESPITE THE FNT. SO...STILL A CHANCE OF SOME
MVFR SHRS UP NORHT ALONG WITH SOME LGT FOG...OTRW GNRL VFR CONDS
OVRNGT INTO EARLY WED. FNT CONTS SWRD ON WED AND MAY TRIGGER SOME
AFTN CONV OVER THE CNTRL AND SRN SITES LDG TO BRIEF REDUCTIONS IN
CIG AND VSBYS. DRIER AIR BHD THE FNT WILL MAINTAIN VFR CONDS THRU
THE END OF THE TAF PD.
OUTLOOK...
THU/FRI/SAT...VFR...EXCEPT FOR POSSIBLE IFR EARLY MORNING VALLEY
FOG...MAINLY KELM.
SUN...VFR...CHC MVFR IN SHWR/TSTM AFTERNOON.
&&
.CLIMATE...
SYRACUSE SHATTERED DAILY RECORD OF 94 DEGREES...BY HITTING AT
LEAST 100 DEGREES AS OF 3 PM...ONLY A COUPLE DEGREES AWAY FROM ALL
TIME RECORD OF 102 SET JULY 9 1936. BINGHAMTON AIRPORT IS
CURRENTLY TIED WITH THE DAILY RECORD AS OF 320 PM /91 DEGREES/.
DAILY RECORD FOR AVOCA IS 96 DEGREES...WHICH WILL BE A CLOSE CALL.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MDP
NEAR TERM...CMG/MLJ/MDP
SHORT TERM...MDP
LONG TERM...BMW
AVIATION...DGM/DJN
CLIMATE...
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
105 AM EDT WED JUL 18 2012
.SYNOPSIS...
AFTER A DAY OF RECORD OR NEAR RECORD HEAT...A COLD FRONT WILL SLIP
SOUTH TO TRIGGER SCATTERED THUNDERSTORMS ACROSS PORTIONS OF CENTRAL
NEW YORK TONIGHT...MAINLY ALONG THE NEW YORK THRUWAY REGION...SOME
OF WHICH COULD BE SEVERE. THE FRONT WILL CONTINUE TO PUSH SOUTH
FOR ADDITIONAL POSSIBLE SEVERE THUNDERSTORMS FOR MAINLY SOUTHERN
NEW YORK AND NORTHEAST PENNSYLVANIA WEDNESDAY. COOLER AND DRIER
AIR WILL BUILD IN BEHIND THE FRONT THURSDAY AND FRIDAY...FOLLOWED
BY WARMING TEMPERATURES OVER THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
1 AM UPDATE...
04Z SUBJECTIVE SURFACE ANALYSIS PLACES MAIN COLD FRONT ALONG A
HAMILTON, ON...TO TRENTON, ON...TO WATERTOWN LINE. AHEAD OF THIS
BOUNDARY OVERALL CONVECTIVE ACTIVITY HAS SHOWN A NOTICEABLE
WEAKENING TREND IN RECENT HRS AS MAIN MID-LEVEL FORCING REMAINS
WELL NORTH OF THE FCST AREA. EARLIER...RADAR TRENDS SHOWED RENEWED
CONVECTION JUST NORTH OF THE LAKE ONTARIO SHORE...HOWEVER NO NEW
DEVELOPMENT IS APPARENT WITHIN THE LAST HR OR SO. REGIONAL HIGH-
RES CONVECTION ALLOWING MODELS SUGGEST A CONTINUED WEAKENING TREND
OVERNIGHT AS MAIN COLD FRONT CONTINUES TO OUTRUN ANY MID-LEVEL
SUPPORT WHICH SHOULD JUST SKIRT NORTHERN PORTIONS OF OUR FCST
AREA. IN FACT...LATEST WATER VAPOR IMAGERY SHOWS A NICE SHORTWAVE
TROUGH LOCATED JUST NORTH OF LAKE HURON...WHICH IS JUST A BIT TOO
FAR NORTH TO HAVE ANY APPRECIABLE AFFECT ON CONVECTIVE TRENDS
ACROSS OUR REGION. THAT SAID...CONSIDERING RECENT RADAR TRENDS AND
GUIDANCE FROM REGIONAL HIGH-RES MODELS TO INCLUDE THE HRRR AND
WRF-ARW...HAVE ELECTED TO LOWER POPS FOR THE REMAINDER OF THE
MORNING HRS AS NOCTURNAL STABILIZATION PROCESSES CONTINUE. DESPITE
THIS...EXPECT THE FRONT TO GRADUALLY SINK THROUGH THE FINGER LAKES
INTO THE SOUTHERN TIER BY MORNING. AFTER 12Z...CONVECTION WILL
ONCE AGAIN DEVELOP ALONG THE BOUNDARY AS DAYTIME HEATING ONCE
AGAIN COMMENCES. WILL FURTHER INVESTIGATE SEVERE POTENTIAL PRIOR
TO THE NEXT UPDATE HOWEVER INITIAL IMPRESSIONS SUGGEST BEST
FORCING WILL AGAIN REMAIN NORTH OF THE AREA WHICH MAY INHIBIT
WIDESPREAD SEVERE COVERAGE.
10 PM UPDATE... CONVECTIVE COVERAGE HAS INCREASED A BIT SINCE
EARLIER THIS EVE ACRS UPSTATE NY...JUST S OF THE SFC FRNT...AND
ALG THE LEADING EDGE OF THE BETTER INSTAB (ML CAPES OF 1000-2000
ATTM STILL OVER MOST OF THE CWA). HOWEVER...THE STGR STORMS/DEEPER
CORES SEEM TO BE CLOSELY TIED TO A CONVERGENCE BNDRY NEAR THE S SHORE OF
LK ONT...WITH A GENERAL WEAKENING TREND NOTED SO FAR ONCE THEY
PUSH FARTHER INLAND.
AS THE SFC FRNT CONTS GRADUALLY SWD OVERNIGHT AND A WELL DEFINED
UPR-LVL WAVE COMES ACRS LK HURON/SRN ONT/FAR NRN NY...WE THINK AN
AREA OF SHRA/TSRA WILL SLOWLY PENETRATE FARTHER SWD ACRS CNY...AND
PERHAPS THE FAR NRN TIER OF PA TWDS DAYBREAK. IN
GENERAL...COVERAGE SHOULD LESSEN WITH SWD EXTENT...AS THE STORMS
OUTRUN THE BETTER FORCED ASCENT AND MORE PRONOUNCED DEEP-LYRD
SHEAR OFF TO THE N. OVERALL...THE SVR THREAT SEEMS MARGINAL...BUT
AN ISOLD STG/SVR STORM CAN`T BE RULED OUT...AND WE`LL CONTINUE TO
MONITOR DEVELOPMENTS.
PREV DISC... 7 PM UPDATE... CONDS REMAIN VERY QUIET ATTM
THROUGHOUT CNY/NE PA. THE AMS IS MODERATELY UNSTABLE (ML CAPES OF
1000-2000...AND LOCALLY HIGHER)...BUT LARGE-SCALE SUPPORT IS
LACKING. ACTIVE CONVECTION REMAINS CONFINED MUCH CLOSER TO THE SFC
FRNTL BNDRY...AND ALSO FORCING FROM A SERIES OF UPR-LVL
WAVES...FROM WI/NRN MI EWD THROUGH SRN ONT AND FAR UPSTATE NY.
AS THE NGT PROGRESSES...WE STILL EXPECT THAT THE SFC FRNT WILL CONTINUE
ITS SLOW SWD PUSH...AND ALSO THAT A WELL DEFINED UPR-LVL PV LOBE
WILL TRACK ESEWD FROM THE NRN LKS RGN TWDS UPSTATE NY AFTER 06Z.
ALTHOUGH AVAILABLE INSTABILITY SHOULD BE SOMEWHAT LESS BY
THEN...THERE WILL LIKELY BE ENOUGH OF IT (ML CAPES STILL NEAR OR
ABV 1000) TO INITIATE SOMEWHAT BETTER COVERAGE OF
SHRA/TSRA...GIVEN IMPROVED LIFT FROM JUST MENTIONED SYSTEMS.
POP/WX GRIDS WERE TWEAKED TO INDICATE ONLY ISOLD COVERAGE IN THE
FAR N THROUGH MUCH OF THE EVE (03-06Z)...WITH SCTD CONVECTION
COMING IN FROM WNW TO ESE IN THE 06-10Z TIME FRAME. OVERALL...WE
FEEL THE SVR THREAT IS SOMEWHAT LIMITED...BUT COMBINATION OF
LINGERING INSTAB...IMPROVING DEEP-LYRD SHEAR (0-6 KM VALUES OF
30-40 KT)...AND BETTER FORCED ASCENT COULD CONCEIVABLY TRIGGER A
FEW STG/SVR STORMS LATER TNT. WE`LL CONTINUE TO MONITOR.
JUST MINOR CHGS MADE TO NEAR-TERM TEMP/DEW PT GRIDS EARLY THIS EVE.
EARLIER DISC... 300 PM UPDATE... SEVERE THUNDERSTORM WATCH REMAINS IN
EFFECT UNTIL 9 PM FOR ONEIDA COUNTY...THOUGH IT WILL TAKE UNTIL
NEAR THE END OF THAT WATCH /PERHAPS EVEN AFTER/ FOR THE THREAT TO
PEAK. HEAT ADVISORY ALSO REMAINS IN EFFECT FOR THE LAKE PLAIN TO
MOHAWK VALLEY WHERE HEAT INDICES ARE NEAR OR SLIGHTLY ABOVE 100
DEGREES. ACTUAL TEMPERATURE IN SYRACUSE WITH DOWNSLOPING MANAGED
TO HIT 100 DEGREES SO FAR...EASILY SHATTERING THE DAILY
RECORD...AND GETTING ONLY 2 DEGREES FROM THE ALL TIME RECORD OF
102 SET JULY 9 1936.
FORECAST UPDATED FOR ANTICIPATED EVOLUTION OF CONVECTIVE
DEVELOPMENT...ESPECIALLY NY THRUWAY REGION...THOUGH DELAYED BY A
COUPLE HOURS DEEPER INTO THE EVENING FOR PEAK CHANCES. SURFACE
FRONT EXTENDS ROUGHLY ALONG THE ST. LAWRENCE VALLEY...THROUGH
ONTARIO /JUST NORTH OF LAKE ONTARIO/...BACK TO LAKE HURON AND
CENTRAL LOWER MICHIGAN. IT IS SET TO SAG SLOWLY SOUTH THROUGH
THE AREA LATE THIS EVENING THROUGH MIDDAY WEDNESDAY. SOUTH OF THE
FRONT...ATMOSPHERE WILL BE VERY WARM NOT JUST AT THE SURFACE BUT ALSO
MID LEVELS...INCLUDING 850 MB AT LEAST 23 DEG CELSIUS. THIS MID LEVEL
FOR NOW IS KEEPING CONVECTIVE INHIBITION OVER THE AREA. LATE EVENING
INTO TONIGHT...WE LOSE DIURNAL HEATING BUT CONDITIONS ALOFT BECOME
MORE FAVORABLE WITH WINDS AT UPPER LEVELS GOING FROM CONVERGENT TO
MORE NEUTRAL...AND MID LEVEL LAPSE RATES INCREASE. THE BIG QUESTION IS
WHETHER CONVECTION CAN INITIATE UPSTREAM /PERHAPS FROM THE WAVE
NOW IN UPPER WISCONSIN-NORTHERN MICHIGAN/...AND HOW FAR WILL IT
CARRY THROUGH THE AREA. THE ONE CERTAINTY HERE...IS THAT WITH
INVERTED-V IN THE LOW LEVELS...AND 35-50 KT OF SHEAR THROUGHOUT
THE 2KM-6KM LAYER...CONVECTION WILL BE CAPABLE OF STRONG
WINDS...WHILE LARGE HAIL AND ISOLATED TORNADOES ARE NOT AS LIKELY
BUT ALSO NOT OUT OF THE QUESTION.
BEST CHANCES WILL BE LATE THIS EVENING ACROSS THE NORTHERN
ZONES...ESPECIALLY ALONG AXIS OF THE NEW YORK THRUWAY...AND
PERHAPS EDGING FARTHER SOUTH TO AT LEAST FINGER LAKES-CATSKILLS
AXIS OVERNIGHT AS IT DIMINISHES WITH DECREASING INSTABILITY.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM THURSDAY/...
315 PM UPDATE...
STORM PREDICTION CENTER PLACES SOUTHERN TIER/CATSKILLS AND
NORTHEAST PENNSYLVANIA IN SLIGHT RISK FOR SEVERE WEATHER...WITH 30
PCT DAMAGING WIND RISK CONTOUR INCLUDING MUCH OF NORTHEAST PA.
UPPER DIVERGENCE COINCIDES WITH FRONTAL PASSAGE IN THE MORNING
HOURS...YET LOW LEVEL CONVERGENCE AND DIURNAL HEATING PEAK AS THE
FRONT IS HEADING OUT OF THE AREA. SHEAR IS NOT AS STRONG
WEDNESDAY...AS COMPARED TO THIS AFTERNOON/TONIGHT...BUT OVERALL
LOOKING QUITE ACTIVE FOR THE SOUTHERN HALF OF THE AREA LATE
MORNING INTO EARLY AFTERNOON. ALSO EXPECTING EARLIER INITIATION OF
CONVECTION BECAUSE OF FAVORABLE UPPER LEVEL SUPPORT.
LOWER ELEVATIONS IN THE SOUTHERN ZONES COULD STILL MANAGE 90
DEGREES WITH UNCOMFORTABLE UPPER 60S/NEAR 70 DEW POINTS...BUT
OTHERWISE TURNING COOLER CENTRAL AND NORTH...AS FRONT CONTINUES
TO SLIDE SOUTH...AND DEW POINTS DROP. ANY LINGERING CONVECTION
WEDNESDAY EVENING QUICKLY SHIFTS SOUTH. LOWS IN UPPER 50S NORTH TO
MID-UPPER 60S SOUTH BY DAWN THURSDAY.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
1 PM UPDATE...
COLD FRONT PUSHES SOUTHEAST THROUGH PA AND NJ THURSDAY WITH SURFACE
HIGH PRESSURE BUILDING INTO NY. UPPER LEVEL TROUGH IS OVER NEW
ENGLAND AND PULLING AWAY TO THE NORTHEAST. BY MIDDAY FRI A
SHORT-WAVE APPROACHES AND MAY HELP TO TRIGGER SOME SHOWERS ACROSS
THE POCONO AREA AND WYOMING VALLEY. WEAK RIDGING DURING THE DAY
SATURDAY WITH FAIR SKIES AND HIGHS IN THE MID 80S. WARM FRONT MOVES
THROUGH SATURDAY NIGHT WITH BRINGING SOME CLOUDS AND A CHANCE OF
TSTMS EAST OF LAKE ONTARIO INTO ONEIDA COUNTY. SUNDAY A COLD FRONT
AND UPPER LEVEL TROUGH APPROACH BRINGING A CHANCE FOR SHOWERS AND
THUNDERSTORMS IN THE AFTERNOON INTO MONDAY AS A WEAK COLD FRONT
MOVES SOUTHEAST ACROSS THE REGION. HIGH PRESSURE BUILDS IN TUESDAY.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
VIS SATL IMAGERY SHOWS VFR ACROSS ALL TAF SITES WITH SCT-BKN MID
TO HIGH CLDS ACRS KSYR AND KRME. THERE WERE A FEW CU FADING AWAY
ACROSS OF THE REST OF C NY AND NE PA. FOR THE NEXT 6
HOURS...EXPECT SCT TSRA TO WORK SOUTHWARD AND BE AROUND KSYR 4-6Z
AND KRME 5-7Z. MOST OF THE DEEPEST CONVECTION WAS EAST AND NORTH
OF KRME AND KSYR. LATER TONIGHT MORE SCT TSRA CUD REACH INTO C NY
WELL AFTER MIDNIGHT BUT UNSURE ABOVE COVERAGE AND PROBABILITIES SO
LEFT OUT OF KITH...KBGM AND KELM TAFS. FOR KAVP VERY SMALL CHANCES
OF CONVECTION OVERNIGHT.
A FRONT WILL DROP SOUTH AND CROSS KRME...AND KSYR. THERE IS A
CHANCE OF A ST/SC LAYER BEHIND THIS FRONT WHICH CUD BE MVFR OR
JUST ABV MVFR. FOR NOW WENT 3500 FEET CIGS. THESE CLDS SHUD MIX
OUT PRETTY QUICKLY AND THE REST OF THE PD SHUD BE VFR WITH ONLY A
FEW CU AND MAYBE SOME CI IN THESE AREAS.
FARTHER SOUTH...CD FRNT MOVING SOUTH WILL DEVELOP MORE CONVECTION WITH A
CHC FOR MVFR VSBY WED PM FROM TSRA. BELIEVE CONVECTION WILL INITIATE
ARND KITH AND GROW AND BECOME MORE WIDESPREAD AS IT TRACKS
SOUTHWARD. WENT FOR PROB30 TSRA MVFR AT KITH...KBGM...KELM AND
KAVP AT THIS TIME. TIMING 16-20Z KITH...18-22Z KBGM AND KELM AND
20-24Z AT KAVP. A LOT OF UNCERTAINTIES EXIST AS TO INTENSITY...FLIGHT
CATEGORY AND TIMING SO PLAYED IT AS PROB30 AND MVFR FOR NOW. LATER
SHIFTS CAN REFINE.
WINDS WERE PRESENTLY GUSTY SW 10-20KT WHICH SHUD SUBSIDE AFTER
SUNSET. THEN WINDS WILL SHIFT TO THE N-NW AT KSYR...KRME AND KITH
WED AM AND BY WED PM FARTHER SOUTH.
OUTLOOK...
WED NGT...POSSIBLE MVFR/IFR RESTRICTIONS FROM FOG.
THU/FRI/SAT...VFR...EXCEPT FOR POSSIBLE IFR EARLY MORNING VALLEY
FOG...MAINLY KELM.
SUN...VFR...CHC MVFR IN SHWR/TSTM AFTERNOON.
&&
.CLIMATE...
SYRACUSE SHATTERED DAILY RECORD OF 94 DEGREES...BY HITTING AT
LEAST 100 DEGREES AS OF 3 PM...ONLY A COUPLE DEGREES AWAY FROM ALL
TIME RECORD OF 102 SET JULY 9 1936. BINGHAMTON AIRPORT IS
CURRENTLY TIED WITH THE DAILY RECORD AS OF 320 PM /91 DEGREES/.
DAILY RECORD FOR AVOCA IS 96 DEGREES...WHICH WILL BE A CLOSE CALL.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MDP
NEAR TERM...CMG/MLJ/MDP
SHORT TERM...MDP
LONG TERM...BMW
AVIATION...DJN
CLIMATE...
AREA FORECAST DISCUSSION
NWS BISMARCK ND
429 AM CDT WED JUL 18 2012
.SHORT TERM...TODAY THROUGH THURSDAY NIGHT...
FORECAST HIGHLIGHTS WILL BE HOT AND HUMID CONDITIONS THROUGH THE
PERIOD ALONG WITH CHANCES FOR THUNDERSTORMS. WILL USE AN OVERALL
BLEND.
CURRENTLY...MID LEVEL S/WV TROUGH LIFTING EAST-NORTHEAST ACROSS THE
NORTHERN PLAINS. A BLEND OF THE 00Z GFS AND 05Z HRRR SEEMS TO
CAPTURE REALITY THE BEST WITH OTHER MODELS JUNK. BASED ON THE HRRR
OUTPUT AND LATEST RADAR IMAGERY...WILL MAINTAIN HIGHER POPS WEST
INTO NORTH CENTRAL NEAR THE TRACK OF THE WAVE...AND OVER MY FAR
SOUTHEAST WITH ADDITIONAL STRONG THUNDERSTORMS DEVELOPING INTO
NORTHEAST SOUTH DAKOTA ALONG A SFC TROUGH AXIS. ELSEWHERE OPTED TO
KEEP AT LEAST A SLIGHT CHANCE FOR THUNDER WITH PLENTY OF INSTABILITY
PRESENT ALONG WITH THE WAVE PASSAGE. WHILE THE OVERALL THREAT FOR
SEVERE STORMS THIS MORNING IS LOW...NOT ENTIRELY OUT OF THE
QUESTION. MOST STORMS SHOULD BE HEAVY RAINERS THOUGH WITH PWATS
STILL AT OR ABOVE 1.5 INCHES.
AFTER 12Z MODELS HAVE PRECIPITATION ENDING FROM WEST TO EAST AS THE
S/WV PUSHES FARTHER EAST AND AS A RIDGE OF HIGH PRESSURE BUILDS IN
ACROSS THE WEST. FOR THE 12-18Z PERIOD...WILL KEEP HIGHER POPS NORTH
CENTRAL AND EAST WITH LOWER POPS WEST FOR ANY LINGERING CONVECTION.
MODELS HINT AT AFTERNOON THUNDERSTORMS DEVELOPING EAST OF HIGHWAY 83
SO WILL MAINTAIN CHANCE POPS. MID LEVEL FORCING PRETTY MUCH
NONEXISTENT SO THINKING IS THE THREAT FOR ORGANIZED CONVECTION WILL
BE LOW TODAY AND MAINLY DIURNAL. LITTLE ACTIVITY EARLY TO MID
EVENING WITH THE RIDGE ALOFT SO WILL KEEP THINGS DRY. TEMPERATURES
MUCH WARMER TODAY AS WE SHOULD SEE PLENTY OF SUNSHINE ALONG WITH WAA
AHEAD OF THE RIDGE.
BOTH THE NAM AND GFS INDICATE A LOW LEVEL JET DEVELOPING LATE
TONIGHT WEST INTO NORTH CENTRAL WITH THE WARM FRONT ADVANCING EAST.
WITH THE WAA WILL SEE INCREASING ELEVATED INSTABILITY AS WELL. WHILE
ALL OTHER GUIDANCE IS DRY...THE NAM DOES PAINT SOME QPF IN THIS AREA
SO OPTED TO THROW IN A SLIGHT CHANCE OF THUNDER 06-12Z LATE
TONIGHT/EARLY THURSDAY MORNING.
LOTS OF UNCERTAINTY REGARDING THUNDERSTORM CHANCES THURSDAY AND
THURSDAY NIGHT. PLENTY OF UNSTABLE AIR ALONG WITH A WEAK AREA OF LOW
PRESSURE ACROSS THE LOCAL AREA. MID LEVEL FORCING QUESTIONABLE WITH
THE UPPER LEVEL RIDGE ALOFT. ANY RIDGE RIDER WAVE WOULD BE
SUFFICIENT TO TRIGGER STORMS. WILL KEEP A SLIGHT CHANCE ALL
LOCATIONS FOR THIS TIMEFRAME FOR NOW. VERY HOT AND HUMID THURSDAY
AFTERNOON BEHIND THE WARM FRONT. WHILE 100 DEGREES IS IN THE
FORECAST WEST AND FAR SOUTH CENTRAL...MODELS ARE TRYING TO BRING IN
DRIER AIR IN THE FORM OF DEWPOINTS IN THE 50S. THIS WOULD ACTUALLY
KNOCK DOWN THE HEAT INDEX TO SUB-HEAT ADVISORY LEVELS BELOW 100.
WILL CONTINUE TO MONITOR.
.LONG TERM...FRIDAY THROUGH TUESDAY...
ABOVE NORMAL TEMPERATURES ARE EXPECTED TO CONTINUE THROUGH THE
EXTENDED.
THE MAIN FEATURE THIS EXTENDED PERIOD IS A BROAD RIDGE ACROSS THE
CENTRAL AND NORTHERN PLAINS THAT WILL REMAIN IN PLACE THROUGH THE
WEEKEND. SEVERAL SHORT WAVE TROUGHS MOVE ACROSS THE TOP OF THE RIDGE
KEEPING THE WEATHER ACTIVE THOUGH THE WEEKEND. BY EARLY NEXT WEEK
THE RIDGE BEGINS TO FLATTEN AS MORE SIGNIFICANT SHORTWAVE ENERGY
ENTERING THE NORTHWEST US BEGINS TO MOVE EAST. THE EUROPEAN IS
FASTER THAN THE GFS ON THIS SHORTWAVE BY TUESDAY...BUT NEVERTHELESS
THERE SHOULD BE AN ACTIVE WEATHER PATTERN EXTENDING INTO NEXT WEEK.
ON FRIDAY...THE GFS/NAM BOTH BRING IN A BACKDOOR COLD FRONT
ASSOCIATED WITH A CANADIAN RIDGE RIDER...WHICH WILL MAKE HIGH
TEMPERATURES A BIT TRICKY ON FRIDAY...AND FRIDAY NOW LOOKS A BIT
COOLER THAN THURSDAY DOES....ESPECIALLY NORTH. THE FRONTAL BOUNDARY
ALSO WILL BE THE FOCUS FOR THUNDERSTORMS...MAINLY FRIDAY NIGHT INTO
SATURDAY.
&&
.AVIATION...
AT 4 AM CDT...FROM THE 06Z ISSUANCE
A SURFACE FRONTAL BOUNDARY EXTENDED FROM CENTRAL MONTANA TO
NORTHEAST WYOMING...INTO A LOW IN EASTERN SOUTH DAKOTA. SHOWERS AND
THUNDERSTORMS CONTINUE ACROSS WEST AND CENTRAL NORTH DAKOTA EARLY
WEDNESDAY MORNING...IMPACTING KBIS/KISN/KMOT. AFTER 15Z EXPECT THE
NIGHTTIME THUNDERSTORMS TO DISSIPATE LEAVING VFR CONDITIONS AT ALL
TAF SITES.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...NH
LONG TERM/AVIATION...WAA
AREA FORECAST DISCUSSION
NWS BISMARCK ND
128 AM CDT WED JUL 18 2012
.DISCUSSION...
MID LEVEL S/WV TROUGH NOW LIFTING INTO WESTERN NORTH DAKOTA.
LEANED ON THE HRRR MODEL FOR THIS UPDATE WITH IT BEING THE ONLY
MODEL CAPTURING REALITY AT THIS TIME. BASED ON THE HRRR OUTPUT AND
LATEST RADAR IMAGERY...THIS LED ME TO GO LIKELY POPS THROUGH 09Z
FAR WEST WITH THE LINE OF CONVECTION NOW MOVING INTO WESTERN NORTH
DAKOTA. AFTER 09Z THUNDERSTORMS ARE EXPECTED TO BE MORE
CONCENTRATED OVER MY NORTH CLOSER TO THE BEST FORCING OF THE MID
LEVEL WAVE. WILL GO WITH A 50 POP HERE FOR NOW 09-18Z. ADDITIONAL
THUNDERSTORMS DEVELOPING OVER SOUTH DAKOTA ALONG A SFC TROUGH
AXIS. A FEW OF THESE STORMS COULD IMPACT MY FAR SOUTHEAST SO
INCREASED POPS HERE. ELSEWHERE OPTED TO KEEP A SLIGHT CHANCE FOR
THUNDER IN WITH PLENTY OF INSTABILITY PRESENT ALONG WITH THE WAVE
PASSAGE.
MODELS HINT AT AFTERNOON THUNDERSTORMS EAST OF HIGHWAY 83...WITH
LITTLE ACTIVITY AFTER 00Z. PREVIOUS FORECAST LOOKS GOOD WITH THIS
SO ONLY MINOR EDITS WERE MADE.
BOTH THE NAM AND GFS INDICATE A LLJ DEVELOPING LATE TONIGHT WEST
INTO NORTH CENTRAL. WHILE ALL OTHER GUIDANCE IS DRY...THE NAM DOES
PAINT SOME QPF IN THIS AREA. OPTED TO THROW IN A SLIGHT CHANCE OF
THUNDER 06-12Z WED NIGHT/EARLY THURSDAY MORNING.
&&
.AVIATION...18/06Z ISSUANCE...
SHOWERS AND THUNDERSTORMS WILL LIKELY IMPACT ALL TAF SITES BUT
POSSIBLY KJMS OVERNIGHT. BASED ON UPSTREAM OBS...HAVE INCLUDED A
TEMPO FOR GUSTY WINDS AND REDUCED VSBY IN TSRA AT KISN FROM 06Z-08Z.
MVFR TO POSSIBLY IFR FOG ALSO EXPECTED AFTER THE STORMS MOVE
THROUGH...MAINLY AT KBIS/KDIK/KJMS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...NH
AVIATION...RK
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
824 PM EDT THU JUL 19 2012
.SYNOPSIS...
AN UPPER SHORT WAVE...COMBINED WITH ABUNDANT MOISTURE AND DIURNAL
HEATING PROVIDE UNSTABLE CONDITIONS THROUGH FRIDAY. A COLD FRONT WILL
MOVE THROUGH THE AREA FRIDAY. HIGH PRESSURE BUILDS IN FRIDAY NIGHT
INTO SATURDAY.
&&
.NEAR TERM /THROUGH FRIDAY/...
UPDATED FORECAST TO ACCOUNT FOR EXITING RAIN. ALSO SEVERE THREAT
AND FLOOD THREAT HAS DIMINISHED. SO CANCELLED EACH OF THOSE
WATCHES. UPDATED POP GRIDS TO TIME POSSIBLE CONVECTION NOW OVER
IND/OH. THIS MAY REACH CWA BY 06Z AND CONTINUE THROUGH 12Z. MAIN
FOCUS AND LIFT WILL BE FRIDAY MORNING AND MOVE WESTWARD THROUGH
THE DAY. POP CHANCES WILL DECREASE FROM WEST TO EAST AS WELL
DURING THE DAY.
PREVIOUS DISCUSSION...
AN APPROACHING UPPER LEVEL TROUGH WILL PROVIDE ENOUGH
FORCING OVER A HIGH CAPE...HIGH PRECIPITABLE WATER ENVIRONMENT
THROUGH FRIDAY.
SEVERAL BANDS OF THUNDERSTORMS ARE EXPECTED TO DEVELOP AND MOVE
FROM THE WEST THIS EVENING AND LATER TONIGHT. HPC QPF GUIDANCE
SUGGEST NEAR 3 INCHES MAINLY NORTHERN WV PANHANDLE...SOUTH ALONG
THE OH RIVER INTO PKB THROUGH 12Z FRIDAY.
EXPECT HEAVY DOWNPOURS WITH EVERY SINGLE STORM. MODELS SHOW PRECIPITABLE
WATER EXCEEDING 2 INCHES THROUGH THIS AFTERNOON THROUGH FRIDAY.
THE NAM AND HPC SUGGEST A STRONGER SHOT OF PRECIPITATION OVERNIGHT
TONIGHT. A MODERATE RISK FOR EXCESSIVE RAINFALL STILL IN EFFECT FROM
HPC THROUGH 00Z SATURDAY. DUE TO YESTERDAYS RAINFALL AMOUNTS
MEASURED BY RAINGAGE...BETWEEN 0.5 TO 1.8 INCHES ACROSS NORTH
CENTRAL WV...WHILE RADAR STORM TOTALS...ALTHOUGH
OVERESTIMATED...SHOWED HIGHER AMOUNTS AWAY FROM GROUND
GAGES...GROUNDS ARE NEARLY SATURATED. BESIDES THESE AREAS ARE MORE
PRONE TO FLOODING. THEREFORE...KEPT FLASH FLOOD WATCH FOR SEVERAL
COUNTIES ACROSS THE CENTRAL AND NORTH CENTRAL WV...INCLUDING
ATHENS COUNTY IN SOUTHEAST OH.
ADJUSTED POPS CLOSER TO THE HRRR PER BETTER AGREEMENT ON LACK OF
AFTERNOON CONVECTION...WHILE OTHER MESO AND SYNOPTIC MODELS
OVERDUE PCPN. A DISORGANIZED MCS TYPE FEATURE CONTINUES TO PRODUCE
BANDS OF THUNDERSTORMS ACROSS OH. THE FIRST BAND HAVE REACHED
SOUTHEAST OH BY MID AFTERNOON...AND IS EXPECTED TO MOVE EAST TO
AFFECT THE FLASH FLOOD WATCH AREA EARLY THIS EVENING. ADDITIONAL
BAND OF STORMS ARE EXPECTED TO DEVELOP OVERNIGHT POSING THE THREAT
FOR SIGNIFICANT RAIN ACCUMULATIONS.
MOIST...WARM...AND HIGH SFC CAPE ENVIRONMENT REMAIN IN PLACE ON
FRIDAY...WHILE A SECONDARY VORT MAX MOVES ACROSS ASSOCIATED WITH
THE AFOREMENTIONED UPPER TROUGH. THEREFORE...KEPT HIGH LIKELY POPS
THROUGH THE END OF THE PERIOD FOCUSING THE EASTERN HALF OF THE
AREA.
WENT CLOSER TO THE LAV/MAV NUMBERS THROUGH THE PERIOD.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
BY FRIDAY EVENING THE COLD FRONT IS EXPECTED TO BE NEAR THE OHIO
RIVER. MEANWHILE BEST LARGE SCALE FORCING FOR ASCENT IS LOCATED OVER
THE NORTHEAST PART OF FORECAST AREA. IN ADDITION...A VORT MAX WILL
BE PUSHING SE-WARD ACROSS NORTHERN WV...WITH LIFT ASSOC WITH IT OUT
AHEAD ACROSS NE PART OF CWA. FINALLY...WITH COLD FRONT MOVING INTO
NORTHERN PART OF AREA AND GOOD LLVL MOISTURE CONVERGENCE
NOTED...SHOWERS/STORMS A GOOD BET TO CONTINUE ACROSS MUCH OF THE
AREA WITH THE HIGHEST POPS WEIGHTED ACROSS NE ZONES BY THE EVENING
HOURS. THOUGH GREATEST COVERAGE IS EXPECTED NORTHEAST...BETTER
CHANCE AT STRONG TO SVR WX APPEARS TO BE ACROSS SOUTHERN AND WESTERN
PARTS OF FORECAST AREA WHERE MARGINAL SHEAR COINCIDES BEST WITH
HIGHEST AXIS OF INSTABILITY. HEAVY DOWNPOURS AND STRONG WINDS
CONTINUE TO BE THE PRIMARY HAZARDS MAINLY BTWN 00Z-03Z. DCAPE VALUES
OF BTWN 500J-800J WITH SFC-MIDLEVEL THETA-E DIFFERENCES OF ~25C
PARTICULARLY ACROSS THE WEST ZONES INDICATE BETTER POTENTIAL FOR
STRONG DOWNBURST WINDS IN THESE LOCALES. SHOWERS/STORMS WILL PUSH
EASTWARD AND SOUTHWARD OVERNIGHT WITH DIMINISHING INTENSITY WITH
LOSS OF INSTABILITY.
BY SATURDAY MORNING COLD FRONT SHOULD BE LOCATED ACROSS THE
SOUTHEAST PART OF CWA WITH LARGE SCALE FORCING FOR SUBSIDENCE
OVERSPREADING THE AREA FROM NW/SE. BEST DEEP LAYER MOISTURE WILL BE
LOCATED NEAR AND AHEAD OF THE FRONT AND THUS WILL CONTINUE SLIGHT
CHANCE/LOW CHANCE POPS IN THIS AREA. FRONTAL ZONE WILL STALL TO THE
SOUTH AND SOUTHEAST ALONG WITH MOISTURE WITH CONTINUED CHANCE OF
SHOWERS AND THUNDERSTORMS PRIMARILY FAR EAST AND SOUTH THE REMAINDER
OF SATURDAY. WILL CONTINUE PRIMARILY SLIGHT CHANCE POPS SUNDAY AGAIN
PRIMARILY FOR FAR EASTERN AND SOUTHERN ZONES AS INSTABILITY AND LLVL
MOISTURE REMAIN ENTRENCHED IN THOSE AREAS.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
OPERATIONAL EXTENDED NWP CONTINUES TO BE IN REASONABLY GOOD
AGREEMENT REGARDING GENERAL FEATURES DURING THIS PERIOD...DEPICTING
A STRENGTHENING UPPER LEVEL RIDGE OVER THE CENTRAL CONUS/HIGH PLAINS
REGION WITH ANOTHER OFF SE ATLANTIC COAST...WITH WNW/NW FLOW ALOFT
OVER FORECAST AREA THROUGH MUCH OF THE PERIOD. AS UPPER HIGH
ATTEMPTS TO BUILD EASTWARD...MAX TEMPS WILL REMAIN SLIGHTLY ABOVE
NORMAL LEVEL WITH READING CONTINUING IN THE UPPER 80S/LOWER 90S
LOWLAND AREAS. EXTENDED NWP AND ENSEMBLES ALSO IN DECENT AGREEMENT
WITH MOVING A FRONT INTO THE AREA TUESDAY AND WILL GO AHEAD AND
RAISE POPS INTO THE LOW CHANCE CATEGORY FOR THIS PERIOD. DIFFERENCES
ARISE HOWEVER WITH THE HANDLING OF THIS FRONT HOWEVER AND WILL USE A
BLEND WITH A LEANING TOWARDS THE EC WITH REGARD TO DAYS 6-7. TEMPS
WILL GENERALLY CONTINUE IN THE UPPER 80S/LOWER 90S FOR THE
PERIOD...PERHAPS A FEW DEGREES COOLER TUESDAY WITH THE FRONT/MORE
CLOUDS IN AREA.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
LAST OF THE LINE OF CONVECTION HAS EXITED THE AREA. STILL MVFR TO
IFR IN CIGS AND VSBYS PRETTY MUCH EVERYWHERE FOR THE NEXT HOUR OR
TWO. NEXT LINE OF SHOWERS AND THUNDERSTORMS FORMING OVER IND/OH
WILL CONTINUE TO MOVE EASTWARD AND SHOULD ARRIVE AFT 06Z. MVFR TO
IFR WITH THE STORMS. AREAS OF FOG SHOULD FORM AFTER RAIN MOVES OUT.
VFR FROM WEST TO EAST TOWARDS LATE AFTERNOON FRIDAY AS SYSTEM MOVES
OUT OF THE AREA.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z SATURDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: TIMING AND COVERAGE OF THUNDERSTORMS AND ANY
CATEGORY CHANGES MAY VARY. MORNING FOG COVERAGE MAY VARY.
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.
DATE FRI 07/20/12
UTC 1HRLY 00 01 02 03 04 05 06 07 08 09 10 11
EDT 1HRLY 20 21 22 23 00 01 02 03 04 05 06 07
CRW CONSISTENCY M M M M M H H H H H H M
HTS CONSISTENCY H H H H H H H H H L L L
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY M M M M H H H H H H H H
PKB CONSISTENCY H H M M M H L H H H H M
CKB CONSISTENCY M M M M L L L L L L H H
AFTER 00Z SATURDAY...
IFR FOG POSSIBLE EARLY SATURDAY MORNING.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...JS/ARJ/50
NEAR TERM...ARJ
SHORT TERM...50
LONG TERM...50
AVIATION...JS
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
749 PM EDT THU JUL 19 2012
.SYNOPSIS...
AN UPPER SHORT WAVE...COMBINED WITH ABUNDANT MOISTURE AND DIURNAL
HEATING PROVIDE UNSTABLE CONDITIONS THROUGH FRIDAY. A COLD FRONT WILL
MOVE THROUGH THE AREA FRIDAY NIGHT AND SATURDAY.
&&
.NEAR TERM /THROUGH FRIDAY/...
AN APPROACHING UPPER LEVEL TROUGH WILL PROVIDE ENOUGH FORCING OVER
A HIGH CAPE...HIGH PRECIPITABLE WATER ENVIRONMENT THROUGH FRIDAY.
SEVERAL BANDS OF THUNDERSTORMS ARE EXPECTED TO DEVELOP AND MOVE
FROM THE WEST THIS EVENING AND LATER TONIGHT. HPC QPF GUIDANCE
SUGGEST NEAR 3 INCHES MAINLY NORTHERN WV PANHANDLE...SOUTH ALONG
THE OH RIVER INTO PKB THROUGH 12Z FRIDAY.
EXPECT HEAVY DOWNPOURS WITH EVERY SINGLE STORM. MODELS SHOW PRECIPITABLE
WATER EXCEEDING 2 INCHES THROUGH THIS AFTERNOON THROUGH FRIDAY.
THE NAM AND HPC SUGGEST A STRONGER SHOT OF PRECIPITATION OVERNIGHT
TONIGHT. A MODERATE RISK FOR EXCESSIVE RAINFALL STILL IN EFFECT FROM
HPC THROUGH 00Z SATURDAY. DUE TO YESTERDAYS RAINFALL AMOUNTS
MEASURED BY RAINGAGE...BETWEEN 0.5 TO 1.8 INCHES ACROSS NORTH
CENTRAL WV...WHILE RADAR STORM TOTALS...ALTHOUGH
OVERESTIMATED...SHOWED HIGHER AMOUNTS AWAY FROM GROUND
GAGES...GROUNDS ARE NEARLY SATURATED. BESIDES THESE AREAS ARE MORE
PRONE TO FLOODING. THEREFORE...KEPT FLASH FLOOD WATCH FOR SEVERAL
COUNTIES ACROSS THE CENTRAL AND NORTH CENTRAL WV...INCLUDING
ATHENS COUNTY IN SOUTHEAST OH.
ADJUSTED POPS CLOSER TO THE HRRR PER BETTER AGREEMENT ON LACK OF
AFTERNOON CONVECTION...WHILE OTHER MESO AND SYNOPTIC MODELS
OVERDUE PCPN. A DISORGANIZED MCS TYPE FEATURE CONTINUES TO PRODUCE
BANDS OF THUNDERSTORMS ACROSS OH. THE FIRST BAND HAVE REACHED
SOUTHEAST OH BY MID AFTERNOON...AND IS EXPECTED TO MOVE EAST TO
AFFECT THE FLASH FLOOD WATCH AREA EARLY THIS EVENING. ADDITIONAL
BAND OF STORMS ARE EXPECTED TO DEVELOP OVERNIGHT POSING THE THREAT
FOR SIGNIFICANT RAIN ACCUMULATIONS.
MOIST...WARM...AND HIGH SFC CAPE ENVIRONMENT REMAIN IN PLACE ON
FRIDAY...WHILE A SECONDARY VORT MAX MOVES ACROSS ASSOCIATED WITH
THE AFOREMENTIONED UPPER TROUGH. THEREFORE...KEPT HIGH LIKELY POPS
THROUGH THE END OF THE PERIOD FOCUSING THE EASTERN HALF OF THE
AREA.
WENT CLOSER TO THE LAV/MAV NUMBERS THROUGH THE PERIOD.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
BY FRIDAY EVENING THE COLD FRONT IS EXPECTED TO BE NEAR THE OHIO
RIVER. MEANWHILE BEST LARGE SCALE FORCING FOR ASCENT IS LOCATED OVER
THE NORTHEAST PART OF FORECAST AREA. IN ADDITION...A VORT MAX WILL
BE PUSHING SE-WARD ACROSS NORTHERN WV...WITH LIFT ASSOC WITH IT OUT
AHEAD ACROSS NE PART OF CWA. FINALLY...WITH COLD FRONT MOVING INTO
NORTHERN PART OF AREA AND GOOD LLVL MOISTURE CONVERGENCE
NOTED...SHOWERS/STORMS A GOOD BET TO CONTINUE ACROSS MUCH OF THE
AREA WITH THE HIGHEST POPS WEIGHTED ACROSS NE ZONES BY THE EVENING
HOURS. THOUGH GREATEST COVERAGE IS EXPECTED NORTHEAST...BETTER
CHANCE AT STRONG TO SVR WX APPEARS TO BE ACROSS SOUTHERN AND WESTERN
PARTS OF FORECAST AREA WHERE MARGINAL SHEAR COINCIDES BEST WITH
HIGHEST AXIS OF INSTABILITY. HEAVY DOWNPOURS AND STRONG WINDS
CONTINUE TO BE THE PRIMARY HAZARDS MAINLY BTWN 00Z-03Z. DCAPE VALUES
OF BTWN 500J-800J WITH SFC-MIDLEVEL THETA-E DIFFERENCES OF ~25C
PARTICULARLY ACROSS THE WEST ZONES INDICATE BETTER POTENTIAL FOR
STRONG DOWNBURST WINDS IN THESE LOCALES. SHOWERS/STORMS WILL PUSH
EASTWARD AND SOUTHWARD OVERNIGHT WITH DIMINISHING INTENSITY WITH
LOSS OF INSTABILITY.
BY SATURDAY MORNING COLD FRONT SHOULD BE LOCATED ACROSS THE
SOUTHEAST PART OF CWA WITH LARGE SCALE FORCING FOR SUBSIDENCE
OVERSPREADING THE AREA FROM NW/SE. BEST DEEP LAYER MOISTURE WILL BE
LOCATED NEAR AND AHEAD OF THE FRONT AND THUS WILL CONTINUE SLIGHT
CHANCE/LOW CHANCE POPS IN THIS AREA. FRONTAL ZONE WILL STALL TO THE
SOUTH AND SOUTHEAST ALONG WITH MOISTURE WITH CONTINUED CHANCE OF
SHOWERS AND THUNDERSTORMS PRIMARILY FAR EAST AND SOUTH THE REMAINDER
OF SATURDAY. WILL CONTINUE PRIMARILY SLIGHT CHANCE POPS SUNDAY AGAIN
PRIMARILY FOR FAR EASTERN AND SOUTHERN ZONES AS INSTABILITY AND LLVL
MOISTURE REMAIN ENTRENCHED IN THOSE AREAS.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
OPERATIONAL EXTENDED NWP CONTINUES TO BE IN REASONABLY GOOD
AGREEMENT REGARDING GENERAL FEATURES DURING THIS PERIOD...DEPICTING
A STRENGTHENING UPPER LEVEL RIDGE OVER THE CENTRAL CONUS/HIGH PLAINS
REGION WITH ANOTHER OFF SE ATLANTIC COAST...WITH WNW/NW FLOW ALOFT
OVER FORECAST AREA THROUGH MUCH OF THE PERIOD. AS UPPER HIGH
ATTEMPTS TO BUILD EASTWARD...MAX TEMPS WILL REMAIN SLIGHTLY ABOVE
NORMAL LEVEL WITH READING CONTINUING IN THE UPPER 80S/LOWER 90S
LOWLAND AREAS. EXTENDED NWP AND ENSEMBLES ALSO IN DECENT AGREEMENT
WITH MOVING A FRONT INTO THE AREA TUESDAY AND WILL GO AHEAD AND
RAISE POPS INTO THE LOW CHANCE CATEGORY FOR THIS PERIOD. DIFFERENCES
ARISE HOWEVER WITH THE HANDLING OF THIS FRONT HOWEVER AND WILL USE A
BLEND WITH A LEANING TOWARDS THE EC WITH REGARD TO DAYS 6-7. TEMPS
WILL GENERALLY CONTINUE IN THE UPPER 80S/LOWER 90S FOR THE
PERIOD...PERHAPS A FEW DEGREES COOLER TUESDAY WITH THE FRONT/MORE
CLOUDS IN AREA.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
LAST OF THE LINE OF CONVECTION HAS EXITED THE AREA. STILL MVFR TO
IFR IN CIGS AND VSBYS PRETTY MUCH EVERYWHERE FOR THE NEXT HOUR OR
TWO. NEXT LINE OF SHOWERS AND THUNDERSTORMS FORMING OVER IND/OH
WILL CONTINUE TO MOVE EASTWARD AND SHOULD ARRIVE AFT 06Z. MVFR TO
IFR WITH THE STORMS. AREAS OF FOG SHOULD FORM AFTER RAIN MOVES OUT.
VFR FROM WEST TO EAST TOWARDS LATE AFTERNOON FRIDAY AS SYSTEM MOVES
OUT OF THE AREA.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z SATURDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: TIMING AND COVERAGE OF THUNDERSTORMS AND ANY
CATEGORY CHANGES MAY VARY. MORNING FOG COVERAGE MAY VARY.
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.
DATE FRI 07/20/12
UTC 1HRLY 00 01 02 03 04 05 06 07 08 09 10 11
EDT 1HRLY 20 21 22 23 00 01 02 03 04 05 06 07
CRW CONSISTENCY M M M M M H H H H H H M
HTS CONSISTENCY H H H H H H H H H L L L
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY M M M M H H H H H H H H
PKB CONSISTENCY H H M M M H L H H H H M
CKB CONSISTENCY M M M M L L L L L L H H
AFTER 00Z SATURDAY...
IFR FOG POSSIBLE EARLY SATURDAY MORNING.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...FLASH FLOOD WATCH THROUGH FRIDAY EVENING FOR WVZ009-016>020-
028>031-039-040.
OH...FLASH FLOOD WATCH THROUGH FRIDAY EVENING FOR OHZ075.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...ARJ/50
NEAR TERM...ARJ
SHORT TERM...50
LONG TERM...50
AVIATION...JS
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
736 AM EDT WED JUL 18 2012
.SYNOPSIS...
A COLD FRONT OVER LOWER MICHIGAN WILL MOVE SOUTHEAST ACROSS THE AREA
LATER TODAY AND THEN BECOME STATIONARY ACROSS CENTRAL OHIO
TONIGHT AND THURSDAY. THE FRONT WILL REACH THE OHIO RIVER LATE THURSDAY
NIGHT. HIGH PRESSURE OVER CENTRAL CANADA WILL SLOWLY BUILD TOWARD
THE REGION THROUGH THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A COLD FRONT WILL BE MOVING IN FROM THE NORTH TODAY. A WEAK SHORT
WAVE IS MOVING THROUGH THE NORTHEAST COUNTIES AND IT IS CAUSING
SOME ISOLATED SHOWERS AND THUNDERSTORMS. THE MAIN THREAT SHOULD BE
LATE THIS MORNING AND IN THE AFTERNOON. THE AIRMASS IS UNSTABLE
AND IT DOES LOOK LIKE WE WILL GET SOME HEATING IN THE MORNING. THE
CONVECTIVE TEMPERATURES ARE NEAR 90...SO THE CUMULUS WILL DEVELOP
QUICKLY AND I THINK THE THUNDERSTORMS WILL ALSO DEVELOP FAST. SOME
THUNDERSTORMS COULD EVEN MOVE IN FROM MICHIGAN...HOWEVER...I THINK
MOST OF THEM WILL DEVELOP OVER THE FORECAST AREA. THE AIRMASS IS
UNSTABLE ENOUGH AND WITH THE FRONT APPROACHING SOME OF THE
THUNDERSTORMS COULD BE SEVERE. THE THUNDERSTORMS COULD BEGIN
DEVELOPING AS EARLY AS 10 AM AND SEVERE THUNDERSTORMS WILL BE
LIKELY ESPECIALLY THIS AFTERNOON. THE HRRR MODEL IS A LITTLE
SLOW IN DEVELOPING THE THUNDERSTORMS. THE MAIN THREAT OF ANY
SEVERE WX WILL BE WIND AND HAIL. FAIRLY CONFIDENT THAT A SEVERE
THUNDERSTORM WATCH WILL BE ISSUED TODAY FOR A LARGE PART OF THE
FORECAST AREA.
WENT A LITTLE COOLER ON SOME OF THE HIGHS IN THE NORTH BECAUSE OF
THE EXPECTED CLOUD COVER AND QUICK THUNDERSTORM DEVELOPMENT. AREAS
FROM FINDLAY THROUGH UPPER SANDUSKY TO MARION TO MOUNT VERNON WILL
BE CLOSE TO HEAT ADVISORY CRITERIA...MAINLY UP TO 99. BECAUSE OF
THAT WILL NOT ISSUE A HEAT ADVISORY. IF THE CLOUDS DO NOT DEVELOP
AS EXPECTED A HEAT ADVISORY MAY HAVE TO BE ISSUED.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
EXPECTING THE THREAT OF THUNDERSTORMS TO DECREASE QUICKLY FROM THE
NORTH THIS EVENING. THURSDAY IS A TOUGH FORECAST. THE NAM KEEPS THE FRONT
VERY CLOSE TO THE REGION AND IF THAT IS CORRECT THAT WOULD MEAN A
LOT OF SHOWERS AND THUNDERSTORMS ACROSS THE WHOLE FORECAST AREA.
GOING MORE WITH THE GFS AND ECMWF AND WILL KEEP THE HIGHS POPS
ACROSS THE SOUTHERN PORTION OF THE FORECAST AREA. AS THE FRONT SAGS
SOUTH THURSDAY NIGHT THE THREAT OF THUNDERSTORMS WILL DECREASE
FROM NORTH TO SOUTH. FRIDAY INTO SATURDAY NIGHT WILL BE DRY AS
HIGH PRESSURE BUILDS IN FROM CANADA. USED A BLEND OF GUIDANCE FOR
THE TEMPERATURE FORECAST.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
HIGH PRESSURE OVER THE OHIO VALLEY WILL KEEP SUNDAY QUIET. A FRONTAL
BOUNDARY WILL BE LURKING ACROSS THE CENTRAL LAKES...BUT TIMING THIS
INTO OUR AREA IS STILL DIFFICULT. WILL STICK WITH THE PREVIOUS
FORECAST AND HAVE CHANCE POPS FOR MONDAY. TEMPERATURES WILL BE
WARMING INTO THE UPPER 80S/NEAR 90 FOR SUN-MON. IF FRONT COMES
THROUGH OR IS NEARBY STILL WITH CLOUD COVER...EXPECTING SLIGHTLY
COOLER TUE. HIGH PRESSURE WILL BE NORTH OF THE AREA.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
SLOWING AND WEAKENING COLD FRONT TO SAG SOUTH ACROSS THE AREA
TODAY. LATEST ANALYSIS PLACES IT ACROSS NORTHERN OHIO...BUT THERE
IS SOME CONVECTION BEHIND IT. CONVECTION SHOULD QUICKLY POP UP
LATER THIS MORNING SOUTH OF THE FRONT INTO THE EARLY AFTERNOON
WITH AMPLE INSTABILITY. HAVE CONTINUED THE VCTS MENTION AT THIS
POINT...BUT ALSO ADDED A TEMPO FOR THOSE SITES MOST LIKELY TO GET
TS TODAY. THERE MAY BE A ROGUE SHRA/TS BEFORE THIS...BUT TOO
ISOLATED TO MENTION. SOME SEVERE POTENTIAL WITH STRONG GUSTY
WINDS. HAVE WRAPPED UP CONVECTION BY LATE AFTERNOON NORTH TO MID
EVENING SOUTH. IT REALLY APPEARS THAT CONVECTION WILL BUBBLE UP
EARLY...BE SCATTERED TO NUMEROUS...AND THEN BE OVER. FRONT MAY BE
DIFFUSE AT THIS POINT AND THERE WILL BE LITTLE ALOFT TO SUPPORT
MUCH. WINDS WILL BE RELATIVELY LIGHT TODAY AND WIND SHIFT HARD TO
TIME. THE REST OF WEDNESDAY NIGHT SHOULD BE QUIET. THOSE PLACES
THAT DO GET PRECIP RUN THE POTENTIAL FOR FOG WEDNESDAY
NIGHT/THURSDAY MORNING. WINDS WILL BE LIGHT/VARIABLE AT THIS POINT
AND LOW LEVEL MOISTURE WILL STILL BE PRESENT...BUT WE MAY HAVE A
FAIR AMOUNT OF MID/HIGH CLOUDS TO INHIBIT FOG. FOR NOW HAVE 3-6SM BR.
.OUTLOOK...NON-VFR CONDITIONS POSSIBLE WITH BR/FG LATE TONIGHT INTO
EARLY THURSDAY. A CHANCE OF NON-VFR THURSDAY...MAINLY WEST AND
SOUTH OF KMFD IN SHRA/TS.
&&
.MARINE...
COLD FRONT SINKING SOUTH ACROSS THE LAKE THIS MORNING. SOME
SHOWERS/TS ASSOCIATED WITH IT...BUT MOST OF THE ACTIVITY WILL BE
INLAND. WINDS WILL BE LIGHT FROM THE NORTH AFTER THE FRONT. HIGH
PRESSURE BUILDS ACROSS ONTARIO FOR THU-FRI...SHIFTING EAST SAT/SUN.
THIS WILL PRODUCE A PERIOD OF NORTHEAST FLOW. THIS PERSISTENT FLOW
DOWN THE LENGTH OF THE LAKE WILL LIKELY MAKE THE ISLANDS A LITTLE
CHOPPY. WILL GO WITH AN AVERAGE OF 4 FOOTERS...A SMALL CRAFT ADV MAY
BE NEEDED THU/FRI. COULD DEFINITELY SEE 15 KNOTS...POSSIBLY UPWARDS
OF 20 KNOTS. BY SATURDAY WINDS RELAX AND BY SUNDAY SHIFT TO COME OUT
OF THE SOUTH.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KIELTYKA
NEAR TERM...KIELTYKA
SHORT TERM...KIELTYKA
LONG TERM...OUDEMAN
AVIATION...OUDEMAN
MARINE...OUDEMAN
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
639 AM EDT WED JUL 18 2012
.SYNOPSIS...
A COLD FRONT OVER LOWER MICHIGAN WILL MOVE SOUTHEAST ACROSS THE AREA
LATER TODAY AND THEN BECOME STATIONARY ACROSS CENTRAL OHIO
TONIGHT AND THURSDAY. THE FRONT WILL REACH THE OHIO RIVER LATE THURSDAY
NIGHT. HIGH PRESSURE OVER CENTRAL CANADA WILL SLOWLY BUILD TOWARD
THE REGION THROUGH THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A COLD FRONT WILL BE MOVING IN FROM THE NORTH TODAY. A WEAK SHORT
WAVE IS MOVING THROUGH THE NORTHEAST COUNTIES AND IT IS CAUSING
SOME ISOLATED SHOWERS AND THUNDERSTORMS. THE MAIN THREAT SHOULD BE
LATE THIS MORNING AND IN THE AFTERNOON. THE AIRMASS IS UNSTABLE
AND IT DOES LOOK LIKE WE WILL GET SOME HEATING IN THE MORNING. THE
CONVECTIVE TEMPERATURES ARE NEAR 90...SO THE CUMULUS WILL DEVELOP
QUICKLY AND I THINK THE THUNDERSTORMS WILL ALSO DEVELOP FAST. SOME
THUNDERSTORMS COULD EVEN MOVE IN FROM MICHIGAN...HOWEVER...I THINK
MOST OF THEM WILL DEVELOP OVER THE FORECAST AREA. THE AIRMASS IS
UNSTABLE ENOUGH AND WITH THE FRONT APPROACHING SOME OF THE
THUNDERSTORMS COULD BE SEVERE. THE THUNDERSTORMS COULD BEGIN
DEVELOPING AS EARLY AS 10 AM AND SEVERE THUNDERSTORMS WILL BE
LIKELY ESPECIALLY THIS AFTERNOON. THE HRRR MODEL IS A LITTLE
SLOW IN DEVELOPING THE THUNDERSTORMS. THE MAIN THREAT OF ANY
SEVERE WX WILL BE WIND AND HAIL. FAIRLY CONFIDENT THAT A SEVERE
THUNDERSTORM WATCH WILL BE ISSUED TODAY FOR A LARGE PART OF THE
FORECAST AREA.
WENT A LITTLE COOLER ON SOME OF THE HIGHS IN THE NORTH BECAUSE OF
THE EXPECTED CLOUD COVER AND QUICK THUNDERSTORM DEVELOPMENT. AREAS
FROM FINDLAY THROUGH UPPER SANDUSKY TO MARION TO MOUNT VERNON WILL
BE CLOSE TO HEAT ADVISORY CRITERIA...MAINLY UP TO 99. BECAUSE OF
THAT WILL NOT ISSUE A HEAT ADVISORY. IF THE CLOUDS DO NOT DEVELOP
AS EXPECTED A HEAT ADVISORY MAY HAVE TO BE ISSUED.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
EXPECTING THE THREAT OF THUNDERSTORMS TO DECREASE QUICKLY FROM THE
NORTH THIS EVENING. THURSDAY IS A TOUGH FORECAST. THE NAM KEEPS THE FRONT
VERY CLOSE TO THE REGION AND IF THAT IS CORRECT THAT WOULD MEAN A
LOT OF SHOWERS AND THUNDERSTORMS ACROSS THE WHOLE FORECAST AREA.
GOING MORE WITH THE GFS AND ECMWF AND WILL KEEP THE HIGHS POPS
ACROSS THE SOUTHERN PORTION OF THE FORECAST AREA. AS THE FRONT SAGS
SOUTH THURSDAY NIGHT THE THREAT OF THUNDERSTORMS WILL DECREASE
FROM NORTH TO SOUTH. FRIDAY INTO SATURDAY NIGHT WILL BE DRY AS
HIGH PRESSURE BUILDS IN FROM CANADA. USED A BLEND OF GUIDANCE FOR
THE TEMPERATURE FORECAST.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
HIGH PRESSURE OVER THE OHIO VALLEY WILL KEEP SUNDAY QUIET. A FRONTAL
BOUNDARY WILL BE LURKING ACROSS THE CENTRAL LAKES...BUT TIMING THIS
INTO OUR AREA IS STILL DIFFICULT. WILL STICK WITH THE PREVIOUS
FORECAST AND HAVE CHANCE POPS FOR MONDAY. TEMPERATURES WILL BE
WARMING INTO THE UPPER 80S/NEAR 90 FOR SUN-MON. IF FRONT COMES
THROUGH OR IS NEARBY STILL WITH CLOUD COVER...EXPECTING SLIGHTLY
COOLER TUE. HIGH PRESSURE WILL BE NORTH OF THE AREA.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
SLOWING AND WEAKENING COLD FRONT TO SAG SOUTH ACROSS THE AREA
TODAY. CONVECTION SHOULD QUICKLY POP UP LATER THIS MORNING INTO
THE EARLY AFTERNOON WITH AMPLE INSTABILITY. HAVE CONTINUED THE
VCTS MENTION AT THIS POINT...BUT HAVE MOVED UP THE TIME. THERE MAY
BE A ROGUE SHRA/TS BEFORE THIS...BUT TOO ISOLATED TO MENTION. SOME
SEVERE POTENTIAL WITH STRONG GUSTY WINDS. HAVE WRAPPED UP
CONVECTION BY LATE AFTERNOON NORTH TO MID EVENING SOUTH. IT REALLY
APPEARS THAT CONVECTION WILL BUBBLE UP EARLY...BE SCATTERED TO
NUMEROUS...AND THEN BE OVER. FRONT MAY BE DIFFUSE AT THIS POINT
AND THERE WILL BE LITTLE ALOFT TO SUPPORT MUCH. WINDS WILL BE
RELATIVELY LIGHT TODAY AND WIND SHIFT HARD TO TIME. THE REST OF
WEDNESDAY NIGHT SHOULD BE QUIET. THOSE PLACES THAT DO GET PRECIP
RUN THE POTENTIAL FOR FOG WEDNESDAY NIGHT/THURSDAY MORNING. WINDS
WILL BE LIGHT/VARIABLE AT THIS POINT AND LOW LEVEL MOISTURE WILL
STILL BE PRESENT. FOR NOW HAVE 6SM BR.
.OUTLOOK...NON-VFR CONDITIONS POSSIBLE WITH BR/FG LATE TONIGHT INTO
EARLY THURSDAY. A CHANCE OF NON-VFR THURSDAY...MAINLY WEST AND
SOUTH OF KMFD IN SHRA/TS.
&&
.MARINE...
COLD FRONT SINKING SOUTH ACROSS THE LAKE THIS MORNING. SOME
SHOWERS/TS ASSOCIATED WITH IT...BUT MOST OF THE ACTIVITY WILL BE
INLAND. WINDS WILL BE LIGHT FROM THE NORTH AFTER THE FRONT. HIGH
PRESSURE BUILDS ACROSS ONTARIO FOR THU-FRI...SHIFTING EAST SAT/SUN.
THIS WILL PRODUCE A PERIOD OF NORTHEAST FLOW. THIS PERSISTENT FLOW
DOWN THE LENGTH OF THE LAKE WILL LIKELY MAKE THE ISLANDS A LITTLE
CHOPPY. WILL GO WITH AN AVERAGE OF 4 FOOTERS...A SMALL CRAFT ADV MAY
BE NEEDED THU/FRI. COULD DEFINITELY SEE 15 KNOTS...POSSIBLY UPWARDS
OF 20 KNOTS. BY SATURDAY WINDS RELAX AND BY SUNDAY SHIFT TO COME OUT
OF THE SOUTH.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KIELTYKA
NEAR TERM...KIELTYKA
SHORT TERM...KIELTYKA
LONG TERM...OUDEMAN
AVIATION...OUDEMAN
MARINE...OUDEMAN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1116 AM EDT WED JUL 18 2012
.SYNOPSIS...
A COLD FRONT WILL DROP SOUTHWARD THROUGH CENTRAL PENNSYLVANIA
THIS AFTERNOON AND EVENING. THERE IS A THREAT FOR SEVERE
THUNDERSTORMS UNTIL THE FRONT CAN GET TO THE MASON DIXON LINE THIS
EVENING. THE FRONT WILL THEN BECOME NEARLY STATIONARY ALONG THE
BORDER AND MAINTAIN UNSETTLED WEATHER ACROSS THE SOUTHERN HALF OF
THE KEYSTONE STATE THURSDAY AND FRIDAY. IMPROVING CONDITIONS
SHOULD ARRIVE BY THE WEEKEND AS HIGH PRESSURE PUSHES THE FRONTAL
ZONE SOUTHWARD.
&&
.NEAR TERM /THROUGH TONIGHT/...
TEMPS TO 90F ALREADY IN THE LOWER SUSQ...AND M80S EVERYWHERE ELSE.
CAPES CLIMBING AS THE HEAT BUILDS WITH 70+ DEWPOINTS. CLUSTER OF
WEAK TSTORMS MOVING INTO THE CENTRAL MTS ATTM LOOK LIKE THEY WILL
CONTINUE WITH LITTLE CHANGE IN ATMOS IN ADVANCE OF THE STORMS.
ADDITIONAL CU POPPING SIGNALING LLVL INSTABILITY. WIND SHIFT
ALREADY AT BFD AND FKL AND ONLY WEAK CONVERGENCE THERE. THE BEST
CONVERGENCE IS INTO THAT CLUSTER OF CELLS. RUC FINALLY HAS A
HANDLE ON CURRENT CONVECTION AND CONTINUES TO FLARE UP MOST STORMS
ALONG THE FRONT AS IT DROPS SWRD THROUGH THE CENTRAL MTS AND INTO
THE SRN TIER LATER THIS AFTN AND EVENING.
THE ENTIRE CWA REMAINS IN THE SPC D1 CATEGORICAL SLIGHT RISK WITH
THE PRIMARY SVR TSTM HAZARDS BEING DAMAGING WINDS AND LARGE HAIL.
STRONGER MID-UPPER LVL WINDS WILL REMAIN NORTH OF THE LEADING
FRONTAL BOUNDARY. HOWEVER 25-35KTS OF EFFECTIVE SHEAR AND DEEP
LAYER WLY FLOW WILL FAVOR BOTH MULTI AND SUPER CELLULAR STRUCTURES
WITH SOME LINEAR/BOWING LINE SEGMENTS. WEAK 0-1KM SHEAR AND HIGH
LCL/S SUGGEST THAT THE ENVIRONMENT IS LIKELY NOT CONDUCIVE FOR
TORNADOES.
SHOWER/TSTM ACTIVITY ACROSS THE SOUTH SHOULD LINGER INTO THE 03Z
TIMEFRAME BEFORE WEAKENING AND GRADUALLY DISSIPATING INTO TONIGHT.
LLVL THETA-E AND PWAT GRADIENT SUGGESTS THAT THE E-W FRONTAL ZONE
WILL STALL JUST SOUTH OF I-80...WITH THE BEST CHC FOR ADDNL PCPN
OVER THE SRN 1/2 OF THE CWA OVERNIGHT.
HIGHS TODAY WILL AVG +10 DEGREES ABOVE MID JULY CLIMATE
NORMALS...RANGING FROM THE MID-UPPER 80S IN THE NRN/WRN MTNS TO
LOW-MID 90S ACRS THE CENTRAL-SRN VALLEYS. A HEAT ADVY REMAINS IN
EFFECT FOR THE LWR SUSQ VLY...WHERE HEAT INDEX VALUES WILL PEAK IN
THE LOW 100S DURING THE MID-LATE AFTN.
&&
.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
MDL DATA INDICATES QUASI-STATIONARY EAST/WEST FRONT WILL BISECT
THE STATE ON THURSDAY. DIURNAL HEATING OF MOIST AIR MASS SOUTH OF
FRONT SHOULD RESULT NUMEROUS TSRA SOUTH OF I-80 BY AFTN. SVR
THREAT NOT PARTICULARLY HIGH...GIVEN WEAK SHEAR. HOWEVER...MODERATE
CAPES SUGGEST A FEW STRONG PULSE-TYPE STORMS ARE POSSIBLE OVER THE
SOUTH. NR HAVE PAINTED A SHARP DECREASE IN POPS IN DRIER AIR MASS
ACROSS NORTHERN PA. DESPITE MCLDY SKIES ACROSS THE SOUTHERN HALF
OF THE STATE...TEMPS STILL LIKELY TO BE A BIT ABV SEASONAL NORMS
ON THURSDAY. ENS MEAN 850MB TEMPS SUPPORT HIGHS FROM THE L80S OVR
THE ALLEGHENY PLATEAU...TO THE U80S IN THE SUSQ VALLEY.
LATEST MDL GUIDANCE A BIT STRONGER WITH SHORTWAVE TROF DROPPING
INTO THE OHIO VALLEY LATE THIS WEEK. THE RESULTING SFC WAVE WILL
LIKELY SPREAD AN OVERRUNNING RAINFALL INTO SOUTHERN PA LATE THU
NIGHT.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
POTENTIAL EXISTS FOR A SUBSTANTIAL RAINFALL ACROSS SOUTHERN PA
FRIDAY...AS SLOW MOVING WAVE OF LOW PRESSURE PASSES SOUTH OF THE
MASON DIXON LINE. 00Z GEFS INDICATING AN ANOMALOUS EASTERLY LL JET
AND PWATS FOCUSED ALONG THE S TIER COUNTIES...A SIGNAL FOR
SIGNIFICANT PRECIP. CURRENT GEFS MEAN QPF BTWN FRI AND FRI NITE IS
ARND AN INCH OVR THE S TIER. ALTHOUGH LIGHTER AMTS ARE EXPECTED
FURTHER NORTH...BULK OF MDL DATA SUGGESTS SOME RAIN IS LIKELY FOR
ALL BUT THE N TIER. HAVE RAISED POPS ACCORDINGLY. CLOUD COVER AND
RAIN SHOULD RESULT IN A COOL FRIDAY WITH TEMPS ACROSS THE CENTRAL
MTNS LIKELY ONLY REACHING THE L70S.
CONFIDENCE OF A DRY WEEKEND STILL HIGH...AS ALL MED RANGE
GUIDANCE PUSHES TROF AND ASSOC SFC LOW EAST OF THE AREA. CAN/T
RULE OUT AN ISOLD PM TSRA ACROSS THE S TIER SATURDAY IN VICINITY
OF STALLED FRONTAL BNDRY NR THE MASON DIXON. TEMPS SHOULD START
THE WEEKEND NR NORMAL...THEN A WARMING TREND EXPECTED SUNDAY...AS
SFC HIGH PASSES EAST OF PA AND RETURN SW FLOW OVERSPREADS THE
REGION.
A DRY NW FLOW PATTERN APPEARS LIKELY EARLY NEXT WEEK WITH TEMPS A
BIT ABV SEASONAL NORMS BASED ON ENS MEAN 850 TEMPS. A COUPLE OF
SHORTWAVES DIVING SE ACROSS THE REGION COULD BRING A SHRA/TSRA TO
PARTS OF THE AREA MON/TUE. HOWEVER...GEFS PWATS NOT IMPRESSIVE...SO
SIG RAINFALL SEEMS UNLIKELY.
&&
.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
COLD FRONT PUSHING SOUTH SEEMS TO BE PAST KBFD AT THIS TIME...BUT
SHOWERS TO THE NW WILL KEEP MENTION OF SHRA THERE FOR EARLY THIS
AFTN. MOISTURE HIGH SO REDUCTIONS TO IFR POSSIBLE IF THE HEAVIEST
DOWNPOURS MOVE RIGHT OVER ANY OF THE LOCAL TERMINALS.
HOWEVER...THE RISK FOR IFR IS SO LOW/VAGUE THAT I WON/T DROP ANY
SPECIFIC TERMINAL TO IFR EVEN TEMPO FOR THE TIME BEING.
THE FRONT WILL TRIGGER NMRS TSTMS INTO THE EVE HOURS. SOME STORMS
MAY BE STG-SVR WITH LOCALIZED CONVECTIVE WIND/HAIL THREATS. THE
FRONTAL BOUNDARY WILL BECOME NEARLY STATIONARY NEAR THE PA/MD
BORDER THUR- FRI...KEEPING UNSETTLED CONDS ACRS S-CENTRAL PA. A
MOIST EAST/SOUTHEAST UPSLOPE FLOW WILL DEVELOP AS HIGH PRES BUILDS
ACRS SE CANADA...AND LKLY BRING LOWER CIGS OCNL SHRA/TSRA TO SRN
AIRFIELDS THRU THE END OF THE WEEK. HIGH PRES SHOULD FINALLY TAKE
CONTROL OF THE REGIONAL WEATHER PATTERN AND BRING WDSPRD VFR OVER
THE WEEKEND.
OUTLOOK...
FRI...MVFR WITH OCNL -RA CENTRAL/SOUTH.
SAT-SUN...MAINLY VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR PAZ036-056-057-
059-063>066.
&&
$$
SYNOPSIS...DANGELO/STEINBUGL
NEAR TERM...DANGELO/STEINBUGL
SHORT TERM...FITZGERALD
LONG TERM...FITZGERALD
AVIATION...DANGELO/STEINBUGL
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1227 PM CDT WED JUL 18 2012
.UPDATE...
18Z TAF DISCUSSION.
&&
.AVIATION...
LATEST RADAR IMAGERY SHOWS SCATTERED SHRA/TSRA DEVELOPING ACROSS
MUCH OF THE CWA. MORNING HRRR RUNS SHOW CONTINUED AND FAIRLY
WIDESPREAD CONVECTION THROUGH THE AFTERNOON/EARLY EVENING...AND
WILL MENTION VCTS AT ALL AIRPORTS WITH TEMPO TSRA AT CSV.
AMENDMENTS TO TAFS WILL BE POSSIBLE IF DIRECT TS IMPACTS APPEAR
MORE LIKELY AT CKV/BNA. CONVECTION EXPECTED TO GENERALLY DISSIPATE
AFTER 02Z WITH GRADUAL CLEARING AFTERWARDS...BUT ISOLATED
ACTIVITY MAY CONTINUE THROUGH THE NIGHT AS AIRMASS WILL REMAIN
HIGHLY MOIST/UNSTABLE. PATCHY FOG WITH MVFR/IFR VIS EXPECTED AT
CSV OVERNIGHT. LIGHT WEST TO SOUTHWEST WINDS ANTICIPATED THROUGH
THE TAF PERIOD.
&&
.PREV DISCUSSION... /ISSUED 1002 AM CDT WED JUL 18 2012/
UPDATE...
DOING A QUICK MORNING UPDATE TO ADJUST HIGH TEMPS GIVEN THAT
MORNING TEMPS ARE OFF TO A HIGHER START THAN GRIDS REFLECTED.
HOWEVER AFTERNOON SCATTERED CONVECTION AND INCREASED CLOUD COVER
WILL HAVE SOME AFFECT ON TEMPS SO ONLY BUMPED UP A DEGREE OR TWO.
OTHERWISE HAVE SLIGHT CHC WORDING THROUGH THE MORNING WITH SCT
CONVECTION THIS AFTERNOON.
PREV DISCUSSION... /ISSUED 542 AM CDT WED JUL 18 2012/
AVIATION 12Z DISCUSSION...
WEAK UPPER TROUGHING ACROSS THE SOUTHEASTERN U.S. WILL COMBINE
WITH HUMID CONDITIONS TO WARRANT A CONTINUATION OF ISOL TO SCT
CONVECTION THROUGH THE TAF PD. OTW...CIGS BELOW 3KFT NOT EXPECTED.
VSBYS WILL REDUCE DOWN TO THE 3-5SM LEVEL GENERALLY AFT 07Z.
DISCUSSION... UPPER HIGHS CONTINUE TO SLOWLY BREAKDOWN AS WEAK
TROUGH AXIS/ IMPULSE PASS NORTH. THIS HAS ALLOWED DEEPER MOISTURE
ADVECTION TO CONTINUE ALTHOUGH CURRENTLY LOW-LEVEL MOISTURE
MODEST. WEAK SHEAR JUST EAST HELPING TO FIRE ISO STORMS VERY NEAR
THE PLATEAU.
MOISTURE WILL CONTINUE TO DEEPEN SOME TODAY AHEAD OF GOOD IMPULSE/
VERY WEAK TROUGH WORKING DOWN TOWARD 00Z. WEAK CAP CURRENTLY EXISTS
BUT WILL LIKELY BREAK PER-18Z. BY THEN...THERMODYNAMIC PARAMETERS
WELL RAMPED UP THUS EXPECT SCT CONVECTION TO START FAIRLY EARLY
TODAY.
CENTER OF ML/UL HIGHS RETROGRADE BACK INTO THE PLAINS TONIGHT AND
HOLD THERE INTO LATER FRIDAY. THIS WILL ALLOW INITIAL WEAK TROUGHS
TO SETTLE OVER THE EASTERN US TONIGHT...BECOMING SHARPER THURSDAY
THROUGH MUCH OF FRIDAY. AMPLE MOISTURE/ENHANCED VERTICAL MOTION
AND PRESENCE OF FRONTAL BOUNDARY BY EARLY FRIDAY SETTING THE AREA
UP FOR PRETTY ACTIVE WX TO END THE WORK WEEK. STEEPENED LAPSE
RATE/STRONGER INSTABILITY ALSO LIKELY TO PRODUCE ISO STRONG-
SEVERE STORMS...ESPECIALLY THURSDAY/THURSDAY NIGHT AS FRONTAL
BOUNDARY DROPS INTO THE TN VALLEY.
FRIDAY NIGHT ML/UL TROUGH PUSHES JUST EAST...SETTING FRONTAL
BOUNDARY/DEEP MOISTURE JUST SOUTH. UPPER RIDGE AXIS AT THIS POINT
SETTLES OVER THE OH VALLEY. THIS WILL BRING A DRY WEEKEND FOR MOST
ACROSS THE MID-STATE BUT THE AREA RETURNS TO A MORE DIURNAL STORM
PATTERN EARLY-MID NEXT WEEK AS MOISTURE CREEPS BACK.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHAMBURGER
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
226 PM CDT WED JUL 18 2012
.SHORT TERM...TONIGHT AND THURSDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A COMPLICATED
SYNOPTIC PATTERN ACROSS THE REGION AT THE MOMENT. FIRST
OFF...REMNANT MCV CONTINUES TO WEAKEN AS IT MOVES NORTHEAST OVER
NORTHWEST WISCONSIN. CAN STILL EXPECT AN AREA OF SHOWERS AND
THUNDERSTORMS MOVING ACROSS NORTH-CENTRAL AND FAR NORTHEAST
WISCONSIN THROUGH LATE AFTERNOON. PERHAPS A BIGGER CONCERN WILL BE
A DEVELOPING CLUSTER OF SHOWERS AND STORMS OVER SOUTHERN MINNESOTA
AND NORTHERN IOWA THAT IS TRACKING NORTHEAST AS WELL. THIS CLUSTER
IS ALSO GETTING THAT MCV LOOK TO IT AND ITS TRACKING IN THE SAME
TRAJECTORY AS THE MCV FARTHER NORTH. THE LATEST TIMING WOULD CALL
FOR THIS NEXT CLUSTER OF STORMS TO MOVE INTO CENTRAL WISCONSIN
AROUND 00Z. OTHERWISE...THE 850MB BAROCLINIC ZONE REMAINS IN PLACE
FROM NW WISCONSIN TO AROUND KEWAUNEE THIS AFTERNOON. AS SHORTWAVE
ENERGY OVER THE PLAINS INTERACTS WITH THIS THERMAL
GRADIENT...THUNDERSTORM CHANCES AND SEVERITY ARE THE MAIN FORECAST
CONCERNS IN THE SHORT TERM.
TONIGHT...MODELS DO NOT HAVE THE CURRENT WEATHER HANDLED VERY
WELL...SO COULDNT REALLY RELY ON ANY PARTICULAR GUIDANCE. MCV
MOVING OVER NORTHWEST WISCONSIN IS PUTTING A MONKEY WRENCH INTO THE
PLANS...THOUGH THINK IT WILL CONTINUE TO GRADUALLY WEAKEN AS IT
MOVES EAST. WHAT IMPACT THIS MCV WILL HAVE ON THUNDERSTORM
DEVELOPMENT FOR TONIGHT IS NOT CLEAR. IT MAY NOT HAVE MUCH IMPACT
ASSUMING THE STRENGTHENING TRENDS OF THE THUNDERSTORM CLUSTER OVER
SOUTHERN MINNESOTA CONTINUE. AS MENTIONED EARLIER...THIS
THUNDERSTORM COMPLEX WILL ARRIVE EARLY THIS EVENING OVER CENTRAL
WISCONSIN BEFORE TRACKING OVER THE FOX VALLEY AND NE WISCONSIN LATER
IN THE EVENING ASSUMING ITS DIRECTION OF TRAVEL DOES NOT CHANGE. IT WILL
ENCOUNTER ELEVATED CAPES TONIGHT FROM ABOUT 500-800 J/KG SO CANNOT
RULE OUT A STORM BECOMING FEISTY AND PRODUCING NEAR SEVERE
WEATHER...BUT ODDS OF ANYTHING SEVERE HAPPENING IS LOW. HEAVY RAIN
LOOKS TO BE THE MAIN THREAT AND 1 TO 2 INCHES OF RAIN APPEARS POSSIBLE.
HAVE BROAD BRUSHED POPS FOR THE 12 HOUR PERIOD TONIGHT AND HAVE
INCREASED THEM TO LIKELY. WITH THE EXPECTED CLOUD COVER AND
STORMS...RAISED LOWS A COUPLE DEGREES.
THURSDAY...THE SHORTWAVE TROUGH WILL PASS ACROSS THE FORECAST AREA
DURING THE MORNING AND HELP PUSH THE 850MB BAROCLINIC ZONE TO THE
SOUTH BY MIDDAY. WITH CONVERGENCE WEAKENING DURING THE AM
HOURS...WILL KEEP POPS LOW TOMORROW MORNING THEN CLEAR THEM OUT FOR
THE AFTERNOON. PLENTY OF MORNING CLOUD COVER...PLUS LINGERING LOW
LEVEL MOISTURE IN COOL EAST FLOW...SHOULD KEEP TEMPERATURES DOWN
AND WILL SHOW HIGHS IN THE MIDDLE TO UPPER 70S.
.LONG TERM...THURSDAY NIGHT THROUGH NEXT WEDNESDAY...PCPN TRENDS
AND TEMPERATURES ARE THE MAIN FCST CONCERNS.
WEAK HIGH PRESSURE WILL MOVE THROUGH THE AREA ON THURSDAY NIGHT
AND FRIDAY. A FEW MODELS GENERATE SOME LGT PCPN ACROSS NC WI ON
FRIDAY...DUE TO WAA/ISENT LIFT...INCREASING MOISTURE CONVERGENCE
AND ELEVATED INSTABILITY. CURRENT THINKING IS THAT THIS PCPN WILL
STAY NW OF GRB CWA THROUGH FRIDAY.
A COLD FRONT WILL WORK ITS WAY INTO NORTHERN WI ON FRIDAY NIGHT...
THEN GRADUALLY SAG SOUTH ACROSS THE FORECAST AREA OVER THE WEEKEND.
THIS FRONT SHOULD BE THE FOCUS FOR ISOLD/SCT TSTM DEVELOPMENT.
ALTHOUGH IT IS FAR FROM A CERTAINTY...MODELS ARE SUGGESTING THAT
THE FRONT MAY SAG FAR ENOUGH SOUTH ON MONDAY/MONDAY NIGHT TO ALLOW
WEAK HIGH PRESSURE TO SETTLE INTO NE WI. WILL TAKE A CHANCE ON A
DRY FCST FOR THOSE PERIODS FOR NOW.
LOW PRESSURE EXPECTED TO MOVE ACROSS SOUTHERN CANADA DURING THE
MIDWEEK PERIOD...WITH A COLD FRONT APPROACHING FROM THE NORTHERN
PLAINS. SW FLOW IN ADVANCE OF THE FRONT WILL LIFT THE OLD FRONT
BACK TO NORTH AS A WARM FRONT...BRINGING A SURGE OF WARMER AND
MORE UNSTABLE AIR INTO C/NE WI. WOULD NOT BE SURPRISED IF WE
SEE A PERIOD OR TWO OF ORGANIZED SEVERE WX LATER TUESDAY INTO
WEDNESDAY...AS INCREASING DEEP LAYER SHEAR COMBINES WITH THE
BUILDING INSTABILITY.
TEMPERATURES WILL REMAIN ABOVE NORMAL IN THE 80S TO AROUND 90
DURING THE PERIOD...AS H8 TEMPS STAY IN THE UPPER TEENS TO AROUND
20 C RANGE. WARMER H8 TEMPS ARE POSSIBLY BY NEXT WEDS...BUT TEMPS
MAY HELD BACK SOMEWHAT BY CONVECTION.
&&
.AVIATION...DIFFICULT FORECAST FOR THE AIRPORTS THIS GO
AROUND...MAINLY REVOLVING AROUND TIMING OF SHOWERS AND
THUNDERSTORMS. NEXT ROUND WILL MOVE ACROSS NORTH-CENTRAL AND
NORTHEAST WISCONSIN THIS AFTERNOON AND BRING MVFR CIGS AND POSSIBLY
IFR VSBYS IN THE HEAVIER RAIN CORES. THEREAFTER...THINK WILL SEE A
BREAK FOR A FEW HOURS AS THE NEXT ROUND ORGANIZES OVER THE NORTHERN
PLAINS. TIMING WHEN THIS NEXT ROUND ARRIVES IS MERELY GUESS WORK AT
THIS POINT. BEST GUEST THOUGH IS THIS NEXT ROUND WILL ARRIVE MID TO
LATE EVENING ONWARD WHEN AN UPPER LEVEL DISTURBANCE ARRIVES. THOUGH
NOT EXPECTING SEVERE WEATHER AT THIS TIME...LOWER CIGS CAN BE
EXPECTED WITH THIS NEXT ROUND INTO THE IFR RANGE. SOME IMPROVEMENT
IN CONDITIONS APPEARS LIKELY BY LATE MORNING TOMORROW.
MPC
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MPC/KIECKBUSCH
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1158 PM CDT TUE JUL 17 2012
UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND WEDNESDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW THE SURFACE
COLD FRONT STRETCHING FROM ABOUT WISCONSIN RAPIDS TO APPLETON TO
KEWAUNEE EARLY THIS AFTERNOON. ELEVATED CONVECTION MOVED INTO N-C
WISCONSIN THIS MORNING IN A REGION OF UPPER DIVERGENCE...MID-LEVEL
FGEN...AND POSSIBLY AHEAD OF A WEAK MCV. ADDITIONAL CONVECTION HAS
JUST RECENTLY DEVELOPMENT IN THE WARM SECTOR OVER CENTRAL AND
EAST-CENTRAL WISCONSIN AND WILL NEED TO WATCH THIS AREA FOR SEVERE
DEVELOPMENT. WITH ML CAPES APPROACHING 2000 J/KG...INHIBITION HAS
BEEN ERODING THIS AFTERNOON AND THINK AN ISOLATED SEVERE STORM
REMAINS POSSIBLE GENERALLY SOUTH OF A MARSHFIELD TO GREEN BAY LINE.
THE MAIN THREATS WILL BE LARGE HAIL AND DAMAGING WINDS. PRECIP
TRENDS THROUGH TONIGHT ARE THE MAIN FORECAST CONCERNS.
TONIGHT...AS THE UPPER FLOW VEERS TO THE NORTHWEST...THE SURFACE
COLD FRONT WILL GET DRIVEN SOUTH FROM CENTRAL WISCONSIN TO NORTHERN
ILLINOIS. THE 850MB FRONT WILL NOT BE SO QUICK AND WILL LINGER
ALONG THE ROUTE 29 CORRIDOR THROUGH THE EVENING BEFORE SHIFTING TO
THE SOUTH. THOUGH UPPER DIVERGENCE PULLS OUT BY THIS
EVENING...850-700MB FGEN WILL LINGER ALONG THE FRONTAL SLOPE AND
THEN PUSH SOUTH LATE TONIGHT. ANY SURFACE BASED STORMS WILL BE
MOVING SOUTH OF THE FORECAST AREA EARLY THIS EVENING...BUT THE
CONVERGENT FLOW AND MID-LEVEL FGEN WILL KEEP SCATTERED POTENTIAL OF
SHOWERS AND STORMS GOING THROUGH THE NIGHT OVER CENTRAL AND
EAST-CENTRAL WISCONSIN. DO THINK STORM COVERAGE AND INTENSITY WILL
DIMINISH WITH LOSS OF HEATING...SO THE POSSIBILITY OF SEVERE
CONVECTION MAY ONLY OCCUR UNTIL EARLY THIS EVENING. COOLER AND
DRIER AIR WILL BE ARRIVING BEHIND THE FRONT AND TEMPS WILL BE
FALLING INTO THE LOWER 50S NORTH TO MID 60S SOUTH.
WEDNESDAY...A SLIGHT CHANCE OF SHOWERS WILL LINGER ACROSS CENTRAL
WISCONSIN AND THE SOUTHERN FOX VALLEY IN THE MORNING...BUT ELEVATED
CONVERGENCE HAS WEAKENED ENOUGH BY THIS TIME THAT DO NOT THINK THERE
WILL BE MANY ECHOES AROUND. AS A RESULT...WENT DRY FOR THE
AFTERNOON. NORTHERN AND NORTHEAST WISCONSIN WILL ENJOY A COOLER AND
LESS HUMID DAY UNDER PARTLY TO MOSTLY SUNNY CONDITIONS...WITH HIGHS
RANGING FROM THE UPPER 70S TO MID 80S. A FEW UPPER 80S WILL STILL
BE POSSIBLE OVER CENTRAL WISCONSIN.
.LONG TERM...WED NGT THRU NXT TUE. THE LARGE SCALE PATTERN IS
EXPECTED TO CONSIST OF A STRONG/PERSISTENT UPR RDG ALOFT OVER THE
CNTRL ROCKIES/CNTRL PLAINS AND AN UPR TROF OVER THE ERN CONUS.
BIGGEST FCST ISSUE REMAINS THE HANDLING OF SHORTWAVE TROFS MOVING
FROM THE NE PACIFIC...THRU SRN CANADA...THEN DROPPING SE INTO THE
ERN UPR TROF. EACH OF THESE SHORTWAVE TROFS WL BE ACCOMPANIED BY A
WEAK CDFNT WHICH ARE FCST TO DROP INTO WI AND EVENTUALLY STALL AS
THEY ENCOUNTER THE UPR RDG. ANY PCPN CHCS WL BE TIED TO THESE
CDFNTS...BUT AT LEAST WE WL HAVE A COUPLE CHCS FOR PCPN IN THE
EXTENDED PERIOD. TEMPS WL REMAIN ABOVE NORMAL UNTIL FURTHERN
NOTICE.
WHILE THE SFC BOUNDARY REMAINS QUASI-STNRY ACROSS CNTRL IA/NRN IL
WED NGT...THE 8H BOUNDARY TO SIT ACROSS SRN WI WITH A TIGHT
BAROCLINIC ZONE IN THE VCNTY OF THE 8H BOUNDARY. A SHORTWAVE TROF
IS FCST TO MOVE INTO THE WRN GREAT LKS BRINGING MODEST LEVELS OF
FRONTOGENETICAL FORCING INTO THE SRN HALF OF WI. BEST CONVERGENCE
SHOULD BE OVER SRN WI AS WELL...BUT CLOSE ENUF TO WARRANT CHC POPS
OVER CNTRL/E-CNTRL WI. NRN WI APPEARS TO BE TOO FAR AWAY FROM THE
PRIMARY FORCING/LIFT...THUS WL ONLY MENTION SLGT CHC POPS FOR THE
FAR NORTH.
PCPN CHCS ACROSS CNTRL/E-CNTRL WI SHOULD GRADUALLY DIMINISH THU
MORNING AS THE SHORTWAVE TROF BEGINS TO PULL AWAY FROM THE REGION.
A WEAK AREA OF HI PRES IS THEN SET TO BUILD SOUTH INTO THE NRN/WRN
GREAT LKS THU AFTERNOON AND BRING SOME MIXED SUNSHINE BACK TO NE
WI. MAX TEMPS ARE EXPECTED TO BE CLOSE TO SEASONAL NORMALS WITH
PLENTY OF LOCATIONS REACHING THE 80 TO 85 DEG RANGE (COOLER
LAKESIDE).
AS THE HI PRES SETTLES OVER THE REGION THU NGT...QUIET AND MORE
COMFORTABLE CONDITIONS WL EXIST AS COOLER/DRIER AIR FILTERS INTO
NE WI. UNDER MOSTLY CLEAR SKIES AND LIGHT WINDS...THU NGT APPEARS
TO BE THE COOLEST NGT OF THE EXTENDED PERIOD WITH READINGS DIPPING
INTO THE LWR 50S NORTH...AROUND 60 DEGS E-CNTRL WI. NE WI TO STILL
RESIDE IN A NW FLOW ALOFT THRU FRI WITH THE BACK EDGE OF HI PRES
REACHING INTO WI. CLOCKWISE CIRCULATION AROUND THE SFC HI WL BRING
SOME COOLING TO THE LAKESHORE ON E-SE WINDS. THE REST OF THE FCST
AREA TO SEE MORE OF A S-SE WIND AND WITH PLENTY OF SUNSHINE
ANTICIPATED...TEMPS WL BEGIN TO GET WARM ONCE AGAIN AS READINGS
REACH THE MID TO UPR 80S.
ATTENTION TURNS TO OUR NORTH AND WEST FRI NGT WHERE A CDFNT WL
ATTEMPT TO PUSH SE INTO THE WRN GREAT LKS. AS HAS BEEN THE CASE OF
LATE...ANY CDFNT HAS BEEN A SLOW MOVER AND THIS LATEST ONE IS NO
DIFFERENT. LATEST MDL TIMING HAS THIS FNT ONLY REACHING NRN
SECTIONS OF THE GREAT LKS BY SAT AFTERNOON...THUS HAVE MAINTAINED
A DRY FRI NGT AND ONLY A MINIMAL POP FOR THE NORTH ON SAT. A MORE
PREVAILING S-SW WIND WL BRING WARMER/MORE HUMID AIR MASS INTO WI
WITH MAX TEMPS ON SAT AGAIN FLIRTING WITH 90 DEGS AND DEW POINTS
IN THE MID 60S. THE SLOW NATURE OF THIS CDFNT IS EVIDENT AS THE
MDLS NOW DO NOT BRING THE BOUNDARY INTO NRN WI UNTIL SUNDAY. BROAD
LOW-LEVEL WAA COUPLED WITH INCREASING INSTABILITY (CAPES BETWEEN
1K AND 2K J/KG/LI`S AROUND -4)...PLENTY OF MOISTURE (DEW POINTS
IN THE MID TO UPR 60S) AND THE FNT ITSELF SHOULD BE ABLE TO
GENERATE AT LEAST A CHC FOR SHWRS/TSTMS ESPECIALLY OVER THE NORTH.
TEMPS FOR SUNDAY MAY BE TRICKY DEPENDING ON THE AMOUNT OF CLOUD
COVER/EXTENT OF ANY PCPN...BUT DUE TO THE EXPECTED WARM START TO
THE DAY...ANOTHER VERY WARM DAY ON TAP WITH PLENTY OF UPR 80S TO
LWR 90S OVER THE REGION.
THE CDFNT IS PROGGED TO SLOWLY SAG THRU CNTRL/E-CNTRL WI SUNDAY
NGT...BUT WITH THE LOSS OF DAYTIME HEATING...THE SHWR/TSTM
ACTIVITY MAY BECOME MORE WIDELY SCATTERED WITH TIME. ANY PCPN CHCS
FOR MON WL BE FOCUSED OVER THE SRN HALF OF WI AS THE FNT GRINDS TO
A HALT AS IT HITS THE UPR RDG. TEMPS ARE FCST TO BE A BIT COOLER
BY MON WITH LOWER DEW POINTS OVER THE NORTH AS DRIER AIR TRIES TO
PUSH INTO THE AREA. WINDS ARE FCST TO BACK SW ONCE AGAIN BY NXT
TUE AHEAD OF THE NXT CDFNT WHICH IS EXPECTED TO MOVE ACROSS THE
UPR MS VALLEY. BETTER UPR SUPPORT TO BE SITUATED WELL TO OUR NORTH
WHERE A PROMINENT SHORTWAVE TROF TO BE SITUATED. NEVERTHELESS...MAY
NEED TO CARRY SOME SORT OF POP ACROSS PORTIONS OF THE FCST AREA TO
ACCOUNT FOR INCREASING LOW-LEVEL WAA/INSTABILITY PARAMETERS.
&&
.AVIATION...NEARLY WEST TO EAST BANDS OF CONVECTION WILL LINGER
THIS WEDNESDAY MORNING OVER CENTRAL AND EAST CENTRAL WISCONSIN.
MVFR CIGS AND VSBYS WILL BE ASSOCIATED WITH THE SHOWERS AND
STORMS. ACROSS NORTHERN WISCONSIN...PATCHY MVFR VSBYS DUE TO FOG
POSSIBLE THROUGH 14Z. OTHERWISE VFR CONDITIONS WILL PREVAIL TODAY.
SHOWERS AND STORMS WILL BE ON THE INCREASE WEDNESDAY NIGHT.
TDH
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1153 PM CDT TUE JUL 17 2012
.SHORT TERM...THROUGH THURSDAY NIGHT
248 PM CDT TUE JUL 17 2012
MAIN FORECAST CONCERN IS WITH THE RAIN CHANCES THROUGH THE PERIOD.
SURFACE ANALYSIS THIS AFTERNOON SHOWS A COLD FRONT ACROSS SOUTHERN
MINNESOTA INTO CENTRAL WISCONSIN. REGIONAL RADARS INDICATE STORMS
HAVE DEVELOPED NORTH OF THE FRONT ACROSS WISCONSIN.
THE CONVECTION ACROSS WISCONSIN HAS DEVELOPED IN RESPONSE TO A
WEAK SHORT WAVE TROUGH THAT DEVELOPED OUT OF THE STORMS OVER THE
DAKOTAS LAST NIGHT. THIS IS ALSO BEING AIDED BY THE RIGHT ENTRACE
REGION OF THE UPPER LEVEL JET OVER LAKE SUPERIOR. THE BEST CAPE
EXISTS ALONG AND AHEAD OF THE FRONT WITH AN AXIS OF 2500 J/KG OF
ML CAPE FROM CENTRAL INTO EAST CENTRAL WISCONSIN. AS THE WAVE
MOVES EAST THIS AFTERNOON...WOULD EXPECT THE CONVECTION TO
GRADUALLY SINK TO THE SOUTHEAST TOWARD THE HIGHER CAPE BUT MOST
SHOULD REMAIN BEHIND THE FRONT WHERE THERE IS NO CAP IN PLACE. THE
17.12Z HI-RES ARW AND 17.15Z HRRR SHOW THIS TREND OCCURRING WITH
THE BEST CHANCE OF ANYTHING CLIPPING THE AREA IN THE I94 CORRIDOR.
AFTER THIS EVENING THROUGH WEDNESDAY...ANY ACTIVITY THAT DEVELOPS
WILL BE CLOSELY TIED TO THE POSITION OF THE FRONT. THE 17.12Z
MODELS ALL HAVE DIFFERENT SOLUTIONS ON HOW FAR SOUTH THE FRONT
WILL GET BEFORE STALLING OUT. THE NAM AND GFS TAKE THE FRONT INTO
CENTRAL IOWA AND NORTHERN ILLINOIS TONIGHT WHILE THE 17.00Z ECMWF
HAS THE FRONT FROM NORTHERN IOWA ALONG THE WISCONSIN/ILLINOIS
BORDER. ALL THE MODELS SHOW JUST A SLOW SOUTHWARD DRIFT TO THE
FRONT WEDNESDAY. AT THIS POINT...NOT EXPECTING ANY SHORT WAVE
TROUGHS TO INTERACT WITH THE FRONT...BUT THAT COULD CHANGE IF
CONVECTION DEVELOPS OVER THE HIGH PLAINS TUESDAY NIGHT.
THE MODELS THEN DO SHOW A SHORT WAVE TROUGH COMING OUT OF THE FLOW
OVER THE ROCKIES AND TOPPING THE UPPER LEVEL RIDGE AND MOVING
ACROSS MINNESOTA AND WISCONSIN. AGAIN...THE POSITION OF THE FRONT
WILL HAVE A BIG IMPACT ON WHERE ANY CONVECTION MAY DEVELOP. WOULD
BE MORE ENTHUSED ABOUT THE RAIN CHANCES WITH THIS WAVE IF THERE
WAS ANY MOISTURE TRANSPORT OF SIGNIFIGANCE WITH THE WAVE. WITH THE
LACK OF RETURNING MOISTURE AND ANECEDENT DRY CONDTIONS...HAVE HELD
THE RAIN CHANCES FOR WEDNESDAY NIGHT AROUND 40 PERCENT. AS THIS
WAVE THEN EXITS OFF TO THE EAST THURSDAY...EXPECT THE RAIN TO MOVE
EAST AS WELL DURING THE DAY WITH A DRY THURSDAY NIGHT AS HIGH
PRESSURE BUILDS IN FROM THE NORTH.
.LONG TERM...FRIDAY THROUGH TUESDAY
248 PM CDT TUE JUL 17 2012
THE HIGH THEN LOOKS TO REMAIN OVER THE AREA INTO THE START OF THE
WEEKEND BEFORE THE NEXT FRONT STARTS TO SINK INTO THE AREA.
CURRENT INDICATIONS ARE THAT THIS FRONT WILL MOVE SOUTH ACROSS THE
AREA FROM SATURDAY NIGHT THROUGH MONDAY. THE UPPER LEVEL RIDGE IS
STILL EXPECTED TO BE ANCHORED OVER THE CENTRAL PART OF THE COUNTRY
WITH THE BULK OF THE SHORT WAVE ENERGY RIDING UP OVER THE RIDGE
ACROSS SOUTHERN CANADA. NOT OUT OF THE REALM OF POSSIBILITY THAT
ONE OF THESE WAVES COULD TEMPORARILY FLATTEN THE RIDGE AND GET
INTO THE AREA...BUT WOULD NOT COUNT ON THIS HAPPENING. THUS ANY
RAIN WITH THE FRONT SHOULD STAY ON THE SCATTERED SIDE.
&&
.AVIATION...THROUGH 06Z THURSDAY
1151 PM CDT TUE JUL 17 2012
FRONTAL BOUNDARY CONTINUES TO MEANDER NEARBY THE TAF SITES...MAKING
CONVECTIVE FORECAST DIFFICULT. ATTEMPTED TO NARROW DOWN THE MOST
LIKELY TIMING FOR ANY CONVECTION WITH VCTS. MODEL GUIDANCE CONTINUES
TO HINT AT THE POSSIBILITY FOR LIGHT FOG/MIST...BUT DID NOT ADD AS
IT LOOKS TO BE VERY LOW PROBABILITY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
248 PM CDT TUE JUL 17 2012
WI...HEAT ADVISORY UNTIL 9 PM CDT THIS EVENING FOR WIZ041>044-053>055-
061.
MN...HEAT ADVISORY UNTIL 9 PM CDT THIS EVENING FOR MNZ094>096.
IA...HEAT ADVISORY UNTIL 9 PM CDT THIS EVENING FOR IAZ008>011-018-019-
029-030.
&&
$$
SHORT TERM...04
LONG TERM...04
AVIATION...MW
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
400 AM MDT FRI JUL 20 2012
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 400 AM MDT FRI JUL 20 2012
TODAY: A FEW LIGHT SHOWERS AND EMBEDDED THUNDERSTORMS CONTINUED
TO MOVE NORTH-NORTHEASTWARD ACROSS WEST-CENTRAL AND NORTHEAST UTAH
EARLY THIS MORNING. NAM AND HRRR SEEMED TO HANDLE THIS ACTIVITY
WELL AND BOTH INDICATED THE POSSIBILITY OF SOME ISOLATED CELLS
LINGERING THROUGH 15Z.
HIGH PRESSURE CENTERED OVER THE CENTRAL HIGH PLAINS WILL CONTINUE
TO CARRY MONSOON MOISTURE NORTHWARD DURING THE REMAINDER OF THE
DAY. THE DEEPEST MOISTURE WILL BE OVER EASTERN UTAH...BUT MOISTURE
LEVELS SHOULD CONTINUE TO RISE OVER WESTERN COLORADO. DAYTIME
WARMING WORKING ON MONSOON MOISTURE WILL BRING SCATTERED TO
NUMEROUS THUNDERSTORMS TO THE MOUNTAIN AREAS FROM LATE MORNING
INTO THE EVENING. AS DIURNAL CIRCULATIONS BREAK DOWN LATER IN THE
AFTERNOON...EXPECT WIDELY SCATTERED STORMS TO IMPACT THE LOWER
ELEVATIONS.
INCREASED CLOUD AND SHOWER/STORM COVERAGE WILL SHOULD BRING HIGHS
DOWN A FEW DEGREES ACROSS THE REGION.
TONIGHT THROUGH SUNDAY: EASTERN UTAH AND WESTERN COLORADO WILL
CONTINUE TO SIT ON THE WESTERN SIDE OF THE LARGE DOMINATING HIGH
PRESSURE RIDGE PARKED OVER THE CENTRAL CONUS. THIS WILL KEEP US IN
A FAVORABLE POSITION FOR THE MONSOONAL MOISTURE SURGE TO PERSIST
THROUGH THE WEEKEND. THE RIDGE DOES BECOME FLATTENED A LITTLE AS
PACIFIC ENERGY MOVES ACROSS SOUTHWEST CANADA. BUT THIS WILL HAVE
LITTLE IMPACT TO OUR SENSIBLE WEATHER. THE AREA WILL SEE A GRADUAL
INCREASE IN MOISTURE THROUGH SUNDAY. DIURNALLY FAVORED SHOWERS AND
THUNDERSTORMS WILL DEVELOP EACH DAY...WITH SOME ACTIVITY
CONTINUING OVERNIGHT. LOCALIZED HEAVY RAIN WILL BE POSSIBLE. ALSO
IF ANY WEAK BUT UNRESOLVED DISTURBANCES ROTATE ACROSS THE AREA...
SHOWERS AND THUNDERSTORMS WILL BE ENHANCED.
WITH THE INCREASED CLOUD COVER AND BETTER CHANCE OF RAIN...HIGH
TEMPERATURES WILL BE DOWN A FEW DEGREES AS COMPARED TO THE LAST FEW
DAYS.
.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 400 AM MDT FRI JUL 20 2012
THE BROAD AREA OF HIGH PRESSURE INDICATED TO REMAIN QUASI-
STATIONARY OVER THE CENTRAL PLAINS THROUGH NEXT WEEK. AS A
RESULT...MONSOON MOISTURE WILL CONTINUE TO MOVE OVER THE REGION
UNABATED RESULTING IN LARGELY DIURNALLY DRIVEN SHOWERS AND
THUNDERSTORMS EACH DAY. TEMPERATURES WILL HOVER NEAR NORMAL FOR
THIS TIME OF YEAR.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 400 AM MDT FRI JUL 20 2012
THE DAY WILL BEGIN WITH VFR CONDITIONS ACROSS THE REGION. THERE
WILL LIKELY BE A FEW LIGHT SHOWERS LINGERING OVER PORTIONS OF
NORTHEAST UTAH...THOUGH THIS ACTIVITY WILL NOT ADVERSELY IMPACT
FLIGHT CATEGORIES.
MOISTURE MOVING NORTHWARD ACROSS THE REGION COMBINED WITH DAYTIME
HEATING WILL BRING ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS
WITH FEW CELLS APPEARING OVER HIGHER TERRAIN AS EARLY AS 17Z. BY
MIDAFTERNOON...SCATTERED TO NUMEROUS THUNDERSTORM COVERAGE WILL
RESULT IN FREQUENT MOUNTAIN OBSCURATIONS AND GUSTY OUTFLOW WINDS
TO 45 MPH. REGIONAL AIRPORTS FACE THE BEST CHANCE OF THUNDERSTORMS
FROM 21Z TO 03Z WITH THOSE IN CLOSE PROXIMITY TO HIGHER TERRAIN TO
THE SOUTH FAVORED. THESE STORMS WILL BRING BRIEF MVFR CIGS AND/OR
VSBY IN HEAVY RAIN.
SHOWERS AND THUNDERSTORMS WILL DECREASE...BUT NOT FULLY DIMINISH
OVERNIGHT.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
SHORT TERM...NL/EH
LONG TERM...NL
AVIATION...NL
AREA FORECAST DISCUSSION
NWS WICHITA KS
1145 PM CDT THU JUL 19 2012
.AVIATION...06Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
ALL 5 TERMINALS TO MAINTAIN VFR STATUS THROUGH LATE FRI NGT & LIKELY
BEYOND WITH ELY WINDS <=10KTS.
&&
.PREV DISCUSSION... /ISSUED 842 PM CDT THU JUL 19 2012/
UPDATE...
TONIGHT:
WITH TSRA HAVING CALLED IT QUITS OVER SC KS HAVE UPDATED FORECAST TO
REMOVE "EVENING" TSRA DESCRIPTOR FROM THESE AREAS. HAZARDOUS WEATHER
OUTLOOK WILL BE UPDATED VERY SOON.
PREV DISCUSSION... /ISSUED 348 PM CDT THU JUL 19 2012/
DISCUSSION...
ISOLATED SHOWERS AND THUNDERSTORMS WITH A THREAT FOR WIND GUSTS TO
55 MPH MAY LINGER THROUGH THE EARLY EVENING HOURS BEFORE DRIFTING
SOUTH/DIMINISHING IN THE ABSENCE OF HEATING.
A MORE SUBSIDENT REGIME IS ANTICIPATED OVER THE WEEKEND AS THE H5
RIDGE EXPANDS ACROSS THE CENTRAL PLAINS. THE H85-H7 THERMAL
RIDGE/INCREASE IN THICKNESS CONTINUES TO SUPPORT RISING TEMPERATURES
WITH VALUES IN THE 105-109 DEGREE RANGE ANTICIPATED. DEEP VERTICAL
MIXING WILL ALLOW DEWPOINT TEMPERATURES TO PLUMMET DURING THE
AFTERNOON HOURS BUT HEAT INDICES WILL STILL MANAGE TO CLIMB TO
AROUND 105+ DEGREES AT TIMES. THEREFORE THE HEAT ADVISORY WILL BE
EXPANDED THROUGH TUESDAY.
WED-THU...ALTHOUGH TEMPERATURES ARE EXPECTED TO REMAIN WELL ABOVE
NORMAL/POSSIBLY LINGERING IN THE 100-105 DEGREE RANGE THERE MAY BE A
TEMPORARY BREAK DOWN OF THE MID/UPPER RIDGE TOWARD THE MIDDLE OF THE
WEEK AS A ROBUST MID/UPPER TROUGH TRANSLATES EAST ALONG THE
US/CANADIAN BORDER. IF THE RIDGE DOES TEMPORARILY BREAK DOWN IT MAY
BE FAIRLY SHORT-LIVED SO ONLY A SUBTLE TREND DOWN IN TEMPERATURES
WAS INTRODUCED ON THU.
AVIATION...18Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
TOUGH CONVECTIVE FORECAST. STORMS HAVE LINGERED ALONG A COUPLE OF
WEAK BOUNDARIES AND OUTFLOW FROM EARLIER STORMS. LATEST RUC
SEEMS HAVE BETTER HANDLE ON THE CURRENT OBSERVATIONS AND VERY SHORT
TERM TRENDS THAN OTHER GUIDANCE. THIS KEEPS BOUNDARY NORTH OF
KICT/KCNU THROUGH AT LEAST EARLY EVENING AND THEN WILL BLEND INTO
NAM AS BOUNDARY SAGS SOUTH DURING THE NIGHT. OF NOTE RUC SHUTS
DOWN MOST OF THE PRECIPITATION BY 2100 UTC. -HOWERTON
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 75 106 75 105 / 20 10 10 0
HUTCHINSON 76 105 75 103 / 20 10 10 0
NEWTON 78 104 78 103 / 20 10 10 0
ELDORADO 76 104 76 102 / 20 10 0 0
WINFIELD-KWLD 78 107 78 105 / 30 10 10 0
RUSSELL 71 105 71 107 / 10 0 10 0
GREAT BEND 73 105 72 106 / 10 10 10 0
SALINA 74 105 74 105 / 10 10 10 0
MCPHERSON 72 104 73 104 / 20 10 10 0
COFFEYVILLE 78 104 78 103 / 30 10 10 10
CHANUTE 77 101 76 100 / 20 10 10 10
IOLA 75 100 76 101 / 20 10 10 10
PARSONS-KPPF 77 102 77 102 / 30 10 10 10
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY UNTIL 7 PM CDT TUESDAY FOR KSZ032-033-047>053-
067>072-082-083-091>096-098>100.
&&
$$
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
658 PM CDT THU JUL 19 2012
.UPDATED FOR 00Z AVIATION DISCUSSION...
&&
.DISCUSSION...
/ISSUED AT 342 PM CDT THU JUL 19 2012/
A QUICK COMPARISON OF THE 00-HOUR AND 240-HOUR 500MB HEIGHT PROGS
FROM THE ECMWF MAKES ONE OVERWHELMING SUGGESTION FOR THE UPCOMING
7 TO 10 DAYS... NOT MUCH IS GOING TO CHANGE. THE GFS IS NOT TOO
DISSIMILAR WITH RESPECT TO THE LARGE SCALE FLOW... WITH THE
OVERALL CONSENSUS BEING THAT THE BROAD UPPER RIDGE WILL REMAIN IN
PLACE ACROSS THE CENTRAL PART OF THE CONTINENT FOR THE FORESEEABLE
FUTURE. A FEW STRONGER SHORTWAVE FEATURES LOOK LIKE THEY WILL
MANAGE TO DEPRESS THE RIDGE AT TIMES OVER THE NORTH CENTRAL CONUS
AND UPPER MIDWEST... INCLUDING OUR AREA... SO WE WILL CONTINUE TO
SEE A MIX OF WELL ABOVE NORMAL TEMPERATURES/DRY WEATHER AND
SLIGHTLY ABOVE NORMAL TEMPERATURES/CHANCES FOR CONVECTIVE
PRECIPITATION. CONTINUED TO FAVOR THE ECMWF FOR THE DETAILS...
ALONG WITH THE NAM IN THE SHORTER TERM... MAINLY DUE TO THE
CONTINUED WET BIAS SEEN IN THE GFS. OF COURSE... SINCE ALL OF THE
EXPECTED PCPN WILL BE CONVECTIVE AND GENERALLY NOT TIED TO VERY
STRONG FORCING... THERE IS A CONTINUED NEED FOR MORE IN THE WAY OF
LOW-END POPS THAN WHAT WOULD BE PREFERRED. TRIED TO FIND SOME TIME
PERIODS TO REMOVE POPS ALTOGETHER... BUT THEY ARE FEW AND FAR
BETWEEN. SO... ALTHOUGH THERE ARE CHANCES MOST DAYS THROUGH NEXT
WEEK... THINGS WILL CERTAINLY NOT BE WET OVERALL... IT IS SIMPLY
TOO TOUGH TO PIN DOWN TIMING/LOCATION MUCH BEYOND 48 HOURS.
TODAY THOUGH FRIDAY...MAIN CONCERN IN THE NEXT 36 HOURS IS PRECIP
CHANCES WITH NORTHWEST FLOW COMING DOWN FROM THE DAKOTAS...AS WELL
AS POSSIBLE FOG/STRATUS TONIGHT. AFTERNOON SURFACE ANALYSIS SHOWED A
HIGH PRESSURE RIDGE ORIENTED ALONG LAKE SUPERIOR AND EXTENDING
THROUGH SOUTHWEST MINNESOTA. DESPITE THE STAGNANT FLOW WITHIN THE
BOUNDARY LAYER...TURBULENT MIXING FROM THE AFTERNOON HEATING WAS
BEGINNING TO BREAK UP THE LOW LEVEL STRATUS ACROSS THE REGION.
FURTHER UPSTREAM...A FEW SHOWERS AND THUNDERSTORMS WERE MOVING
ACROSS THE EASTERN DAKOTAS AHEAD OF A WEAK SHORTWAVE BARELY APPARENT
IN THE WV IMAGERY. CLEARING ACROSS THE RED RIVER VALLEY HAS LED TO
MLCAPES OF 3000-4000J/KG. EXPECT TO SEE THESE STORMS MOVE EAST
SOUTHEAST DURING THE LATE EVENING HOURS...AND EVENTUALLY WEAKEN TO
SPRINKLES BY THE LATE MORNING. DEEP LAYER SHEAR WILL BE SUFFICIENT
FOR A FEW ISOLATED SEVERE STORMS ACROSS THE NORTHWEST...BUT FOR THE
MOST PART THE STORMS WILL REMAIN ELEVATED AND SHOULD WEAKEN BY 06Z
SIMILAR TO THE 12Z WRF NMM SOLUTION. ONCE THE CLOUDS THIN OUT
TOMORROW...TEMPERATURES SHOULD EASILY REBOUND INTO THE UPPER 80S TO
NEAR 90S...WITH ANOTHER SHOT OF PRECIP FOCUSED ALONG A SURFACE
TROUGH ACROSS THE NORTHERN PART OF THE CWA.
CHANCES FOR PCPN FRIDAY NIGHT SHOULD MAINLY BE OVER THE NORTHERN
PART OF THE CWFA IN ASSOCIATION WITH THE WEAK SURFACE
TROUGH/BACKDOOR FRONT THAT WILL BE SAGGING SOUTH. THESE CHANCES
WILL PUSH SOUTH ACROSS THE REMAINDER OF THE AREA ON SATURDAY AS A
WEAK AREA OF HIGH PRESSURE BUILD ACROSS THE REGION. THE BAROCLINIC
ZONE WILL TRY TO LIFT BACK NORTH THROUGH THE AREA SATURDAY NIGHT
THROUGH SUNDAY AS A WEAK SHORTWAVE MOVES THROUGH THE AREA. GIVEN
THE WARMTH AND MOISTURE OVER THE REGION... AND THE ATTENDANT
INSTABILITY... CERTAINLY THINK SOME SHRA/TSRA WILL BE POSSIBLE...
SO ALLOWED SOME POPS TO WORK INTO THE WEST SATURDAY NIGHT AND
DRIFT EAST ACROSS THE AREA ON SUNDAY. WITH THE BAROCLINIC ZONE
PUSHED NORTH BY SUNDAY NIGHT... DRIED THINGS OUT OVER ALL BUT THE
FAR NORTHERN PORTION OF THE AREA WHICH MAY STILL BE ON THE EDGE OF
THE RING OF FIRE AND MIGRATING PCPN CHANCES. MONDAY LOOKS TO HAVE
A DECENT SHOT AT BEING DRY WITH SURFACE RIDGING OVER THE AREA AND
ANY CONVERGENCE LOOKING TO BE WELL NORTH OR SOUTH OF US... SO KEPT
POPS OUT OF THE FORECAST FOR MONDAY AND MONDAY NIGHT. HOWEVER...
BY TUESDAY A DECENT SURFACE WAVE LOOKS TO DEVELOP OVER THE HIGH
PLAINS... HELPING TO REFOCUS THE BAROCLINIC ZONE/WARM FRONTAL
BOUNDARY OVER MINNESOTA. THIS MAY OCCUR JUST TO OUR NORTH... BUT
GIVEN THE SPREAD IN ENSEMBLE SOLUTIONS ON EXACTLY WHERE THINGS
WILL COME TOGETHER... INCLUDED CHANCE POPS OVER THE ENTIRE AREA
TUESDAY INTO WEDNESDAY... WITH THE GREATEST CHANCE CURRENTLY
LOOKING TO BE TUESDAY NIGHT WHEN THERE IS THE GREATEST OVERLAP IN
THE NUMERICAL SOLUTIONS WITH RESPECT TO THE POSITION OF THE WARM
FRONTAL BOUNDARY AND ITS ASSOCIATED CONVECTIVE FOCUS. STUCK MUCH
CLOSER TO THE ECMWF WITH RESPECT TO TIMING FOR THE WEDNESDAY-
THURSDAY TIME FRAME... WHICH RESULTS IN PUSHING CHANCES FOR PCPN
OUT OF MOST OF THE AREA BY THURSDAY AS THE SURFACE WAVE MOVES TO
THE EAST AND WEAKENS AND AN ANEMIC SURFACE RIDGE BUILDS OVER THE
UPPER MIDWEST.
&&
.AVIATION.../00Z TAF ISSUANCE/
VFR CONDITIONS WERE PREVALENT AT ALL THE TAF SITES THIS
EVENING. THUNDERSTORMS ONGOING ACROSS THE DAKOTAS WILL WEAKEN OVER
THE NEXT FEW HOURS...BUT COULD ON LONG ENOUGH TO KEEP VCSH AT
KAXN...KSTC...AND KMSP. TIME-HEIGHT CROSS SECTIONS SHOW LESS LOW
LEVEL MOISTURE THAN THE PREVIOUS NIGHT...BUT COULD SEE SOME
FOG OR STRATUS DEVELOP LATER TONIGHT. THIS WILL BE LESS LIKELY
ACROSS THE WEST WHERE THE WINDS WILL BE STRONGER. TOMORROW
SOUTHERLY WINDS WILL PICK UP AND EXPECT VFR CONDITIONS THROUGHOUT.
KMSP...TRIED TO NARROW DOWN THE BEST LIKELIHOOD OF VCSH WITH A 1HR
WINDOW...BASED OFF A BLEND OF THE LATEST HRRR RUNS AND 12Z WRF
NMM. PRECIP SHOULD BE LIGHT IF IT DOES INDEED MAKE IT TO THE METRO
AREA. COULD SEE SOME BRIEF MVRF VISBYS AND/OR CEILINGS...BUT THE
REST OF THE AFTERNOON AND EVENING SHOULD BE VFR.
/OUTLOOK/
SATURDAY...VFR WITH TSRA POSSIBLE LATE. WINDS N AT 10G15KTS.
SUNDAY...VFR WITH TSRA POSSIBLE. WINDS S AT 8KTS.
MONDAY...VFR. WINDS NW AT 5G10KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
TRH/JRB
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
307 PM CDT WED JUL 18 2012
.DISCUSSION...
OVERALL THE LARGE SCALE PATTERN WILL CHANGE LITTLE FOR US OVER
THROUGH THE FORECAST PERIOD... WITH THE BROAD UPPER RIDGE
CONTINUING TO REIGN OVER THE CENTER OF THE CONTINENT. WE WILL
CONTINUE TO SEE ABOVE NORMAL TEMPERATURES AS A RESULT... WITH
CHANCES FOR PCPN AND SLIGHT COOL DOWNS TIED TO SHORTWAVES MOVING
THEIR WAY AROUND THE PERIPHERY OF THE UPPER RIDGE. THE GFS AND
ECMWF ARE IN REMARKABLY GOOD AGREEMENT THROUGH EARLY NEXT WEEK...
SO ALTHOUGH THEY MAY BE WRONG IT IS TOUGH TO DEVIATE TOO FAR FROM
WHAT THEY ARE SHOWING WITH RESPECT TO THE BIG PICTURE. WILL STICK
CLOSER TO THE ECMWF FOR SOME OF THE DETAILS... MAINLY DUE TO THE
LOW LEVEL COOL/WET BIASES IN THE GFS AND WHAT APPEARS TO BE AN
ASSOCIATED WET BIAS. IN THE SHORTER TERM... UTILIZED THE NAM AND
SREF FOR POP/WEATHER CHANCES AND A CONSENSUS APPROACH FOR
TEMPERATURES... BLENDING WITH POTENTIAL MIX-DOWN VALUES FOR HIGHS.
AN ELONGATED SHORTWAVE TROUGH CURRENTLY APPARENT ON WATER VAPOR
IMAGERY AND RAP UPPER LEVEL PV ANALYSES EXTENDS FROM SOUTHERN
MANITOBA INTO EASTERN NEBRASKA. A LOWER LEVEL MCV FEATURE CAN ALSO
BE SEEN MOVING EAST INTO SOUTH CENTRAL MINNESOTA. THE LATTER
FEATURE IS WORKING TO SUPPORT THE CONVECTIVE ACTIVITY CURRENTLY
OVER THE SOUTHERN PART OF THE AREA... WITH AN OUTFLOW BOUNDARY
FROM THIS MORNING/S CONVECTION ASSISTING WITH THINGS OVER
SOUTHEAST MINNESOTA. THE LARGER SCALE FRONT/BAROCLINIC ZONE IS
NEAR THE MINNESOTA/IOWA BORDER... AND SHOULD HELP TO FURTHER FOCUS
ACTIVITY AS WE HEAD INTO THE EVENING AND THE AFOREMENTIONED LARGE
SCALE SHORTWAVE TROUGH WORKS THROUGH THE AREA. MLCAPE VALUES AOA
2000 J/KG ARE PRESENT ACROSS MOST OF THE AREA... SO THERE IS NO
SHORTAGE OF INSTABILITY. WITH SOME FORCING WORKING ACROSS THE AREA
THROUGH THE EVENING HOURS... THINK WE SHOULD CONTINUE TO SEE SOME
SHRA/TSRA UNTIL WE SEE MORE SUBSTANTIAL MID-LEVEL DRYING AND
SUBSIDENCE LATER TONIGHT. ISOLATED SEVERE STORMS ARE STILL
POSSIBLE GIVEN THE DEGREE OF INSTABILITY... BUT WITH THE DEEP
LAYER SHEAR GENERALLY AOB 30 KT... THE POTENTIAL FOR WIDESPREAD
SEVERE WEATHER APPEARS TO BE LIMITED GIVEN LACK OF EXPECTED
ORGANIZATION WITH MOST STORMS. HOWEVER... A FEW STORMS COULD TAKE
ADVANTAGE OF LOCALLY ENHANCED SHEAR OWING TO THEIR STORM MOTION...
SUCH AS SOME OF THE ACTIVITY CURRENTLY OVER SOUTHEAST MINNESOTA...
AND THOSE WOULD BE THE STORMS MOST LIKELY TO GENERATE SEVERE WEATHER.
SURFACE RIDGING AND MID-LEVEL DRYING/SUBSIDENCE WILL BUILD EAST
ACROSS THE CWFA OVERNIGHT... BRINGING ANY LINGERING SHRA/TSRA TO
AN END. THE NEXT CHANCE FOR PCPN THEN LOOKS TO HOLD OFF UNTIL
FRIDAY NIGHT AND SATURDAY AS THE BAROCLINIC ZONE LIFTS BACK NORTH
ACROSS THE AREA. AT THIS POINT... THE BEST CHANCE LOOKS LIKE IT
WILL BE NORTH OF OUR CWFA CLOSER TO THE WARM FRONTAL BOUNDARY...
BUT THERE IS SUFFICIENT UNCERTAINTY IN THE BOUNDARY PLACEMENT TO
INCLUDE A CHANCE FOR SHRA/TSRA OVER THE NORTHERN HALF OR SO OF THE
AREA. THESE CHANCES WILL THEN SAG SOUTH AND EAST SATURDAY NIGHT
INTO SUNDAY AS A WAVE TRAVELS EAST ALONG THE NEARLY STATIONARY WARM
FRONTAL BOUNDARY. WILL INCLUDE SOME CHANCES FOR PCPN FROM MONDAY
NIGHT INTO WEDNESDAY AS WELL... AFTER DRYING THINGS OUT LATE
SUNDAY AND SUNDAY NIGHT... WITH THE ECMWF AND GFS BOTH SUGGESTING
WE WILL BE NEAR THE BAROCLINIC ZONE/RING OF FIRE AROUND THE
PERIPHERY OF THE UPPER RIDGE AS A FEW SHORTWAVES DROP EAST-
SOUTHEAST FROM WESTERN AND CENTRAL CANADA.
&&
.AVIATION.../18Z TAF ISSUANCE/
/ISSUED 152 PM CDT WED JUL 18 2012/
ONE CLUSTER OF THUNDERSTORMS CURRENTLY IN SW MN HEADING TO THE
NORTHEAST COULD CAUSE SOME ISSUES THIS AFTERNOON. THUNDERSTORM
COVERAGE SHOULD LARGELY BE CONFINED TO FAR SOUTHERN MN AND
WESTERN WI BY THIS EVENING. FAIRLY HIGH CONFIDENCE IN A DRY
FORECAST FOR TONIGHT. LINGERING MVFR/IFR STRATUS THIS AFTERNOON
SHOULD EXPAND TONIGHT.
KMSP...MAY HAVE TO UPDATE AT SOME POINT TO HIGHLIGHT THE THUNDER
CHANCES THIS AFTERNOON. WHILE MOST OF THE THUNDERSTORM ACTIVITY
WILL REMAIN SOUTH OF THE AIRPORT. THUNDER IS CERTAINLY A
POSSIBILITY AROUND 22Z. WINDS REMAINING OUT OF THE EAST/NORTHEAST
AND BECOMING LIGHTER NEAR SUNSET.
OUTLOOK...
THU NIGHT/FRI...VFR.
SAT...VFR BUT INCREASING HIGH CLOUDS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS TWIN CITIES/CHANHASSEN MN
152 PM CDT WED JUL 18 2012
.UPDATE...
UPDATED FOR THE 18Z AVIATION DISCUSSION BELOW.
.DISCUSSION...
SFC-925MB FRONT DOWN ALONG THE IOWA BORDER THIS MORNING...BUT H85
FRONT BISECTS THE THE MPX CWA FROM THE MADISON AREA OVER TO CHIP
FALLS/EAU CLAIRE. HAVE BEEN SEEING VERY WEAK THETA-E ADVECTION
NORTH OF THIS BOUNDARY AND THAT COMBINED WITH PWATS UP AROUND 2
INCHES AND MUCAPE AROUND 1500 J/KG HAS ALLOWED FOR SCATTERED
CONVECTION NORTH OF THIS H85 BOUNDARY FROM NE SODAK OVER TO GREEN
BAY. THIS WAA REGIME IS IN RESPONSE TO A SHORTWAVE THAT CAN
ACTUALLY BE SEEN ON A RADAR MOSAIC...WITH A NICE SPIN IN THE
REFLECTIVITY DOWN AROUND YANKTON...SD. THE RAP HAS ALSO BEEN
SHOWING A NICE PV ANOMALY ACROSS ERN SODAK THAT HAS HELPED
GENERATE MORE WIDESPREAD CONVECTION THERE. AS WE GO THROUGH THE
DAY...BOUTS OF SCT CONVECTION WILL CONTINUE TO OCCUR THROUGH THE
MORNING WITHIN THE WEAK CORRIDOR OF H85 THETA-E ADVECTION FROM
MAINLY CENTRAL MN INTO CENTRAL WI. THE 18.05 HRRR REFLECTIVITY
FORECAST PROBABLY HAS THE RIGHT IDEA FOR THIS MORNING...JUST
DISPLACED A LITTLE TOO FAR NORTH. AS THE AFTERNOON ROLLS
AROUND...THE PV ANOMALY WILL BEGIN WORKING ACROSS THE SRN HALF OF
THE MPX AREA. HAVE MAINLY 40 TO 50 POPS WORKING ACROSS THE AREA
FROM WRN MN INTO WRN WI THOUGH TONIGHT AS THIS PV FEATURE MOVES
ACROSS. MAY NEED TO BUMP UP POPS MORE AS THIS UPPER FEATURE HAS
HAD LITTLE TROUBLE FORCING CONVECTION OVERNIGHT. AS FOR SVR
POTENTIAL WITH THIS ACTIVITY...LACK OF SHEAR COMBINED WITH
FREEZING LEVELS OVER 14K FEET WILL KEEP THE SVR POTENTIAL PRETTY
MINIMAL WITH THE MAIN THREAT BEING FROM GUSTS WINDS IF WE CAN GET
ROBUST ENOUGH STORMS TO RAPIDLY COLLAPSE.
BESIDE RECEIVING SOME MUCH NEEDED RAIN...THIS WAVE WILL ALSO
PROVIDE CLOUD COVER AND COOLER TEMPS ACROSS MOST OF THE CWA FOR
TODAY. THE ONLY EXCEPTION WILL BE ACROSS SRN MN. +28C 925MB TEMPS
WILL NOT BE TOO FAR AWAY FROM THE I-90 CORRIDOR...AND IF THEY DO
NOT SEE MUCH IN THE WAY OF CLOUD COVER BY THE AFTERNOON...THEN
WILL BE ANOTHER LOWER TO MIDDLE 90S DAY DOWN THERE. DEPENDING ON
CLOUD COVER DURATION...MAY HAVE SOME AREAS STAY IN THE 70S FOR
HIGHS TODAY...ESPECIALLY IN THE NORTHEAST SECTION OF THE
CWA...WHERE TEMPS THROUGH H85 WILL BE A BIT COOLER TO BEGIN WITH.
THESE COOLER TEMPS WILL CONTINUE INTO THURSDAY...FOR WRN WI AT
LEAST...AS STRONG NW FLOW SETS IN ALOFT BEHIND TODAYS SHORTWAVE.
FOR FRIDAY THROUGH TUESDAY...THE BIG PLAYER HERE WILL BE THE
STRONG UPPER RIDGE WE HAVE SEEN ALL SUMMER WAFFLING ACROSS THE
CONUS. BY THURSDAY...ANOTHER 595+DM H5 HIGH WILL BE BUILDING
ACROSS THE HIGH PLAINS WITH THE HEAT BUBBLE WE BEAT BACK SOME
TODAY RAPIDLY REBUILDING TO THE WEST. THIS H5 RIDGE WILL SLOWLY
SHIFT INTO THE CENTRAL PLAINS FROM THE WEEKEND INTO EARLY NEXT
WEEK. UP HERE...THE MPX CWA LOOKS TO BE SITTING NEAR THE NRN
PERIPHERY OF THE RIDGE. THE WARMEST DAYS OF THIS PERIOD LOOK TO BE
FRIDAY/SATURDAY AS THE NAM/ECMWF SHOW 594DM H5 HEIGHTS BUILDING UP
INTO CENTRAL MN INTO WRN WI. THE NAM IN PARTICULAR IS RATHER
AGGRESSIVE WITH WAA INTO THE AREA THESE DAYS...WITH ITS 925-850MB
TEMPS INDICATING ANOTHER ROUND OF UPPER 90S TO 102/3 TYPE HIGHS
BEING POSSIBLE BOTH DAYS. DID BUMP HIGHS UP SOME...ESPECIALLY FOR
FRIDAY...BUT MOST MODELS SHOW A NOCTURNAL CONVECTIVE SYSTEM FIRING
OFF TO THE NORTH FRI NIGHT...THAT MAY TRY TO LAY DOWN INTO NRN
SECTIONS OF THE MPX CWA SATURDAY. GIVEN THE UNCERTAINTIES WITH
CLOUD COVER FOR SATURDAY...WAS A BIT MORE CONSERVATIVE WITH HIGHS
THEN. DUE TO PROXIMITY TO UPPER RIDGE...THE MPX AREA WILL BE PRONE
TO ANY RING OF FIRE CONVECTION SATURDAY THROUGH MONDAY. BY
TUESDAY...BOTH THE ECMWF AND GFS CONTINUE TO SHOW A STRONGER COLD
FRONT SWEEPING ACROSS THE AREA...WHICH AT THIS POINT REPRESENTS
THE BEST CHANCES FOR RAIN AFTER TODAY. THIS FRONT ALSO LOOKS TO
PROVIDE ANOTHER 2 OR 3 DAY REPRIEVE FROM THE HEAT AS WELL.
&&
.AVIATION.../18Z TAF ISSUANCE/
ONE CLUSTER OF THUNDERSTORMS CURRENTLY IN SW MN HEADING TO THE
NORTHEAST COULD CAUSE SOME ISSUES THIS AFTERNOON. THUNDERSTORM
COVERAGE SHOULD LARGELY BE CONFINED TO FAR SOUTHERN MN AND
WESTERN WI BY THIS EVENING. FAIRLY HIGH CONFIDENCE IN A DRY
FORECAST FOR TONIGHT. LINGERING MVFR/IFR STRATUS THIS AFTERNOON
SHOULD EXPAND TONIGHT.
KMSP...MAY HAVE TO UPDATE AT SOME POINT TO HIGHLIGHT THE THUNDER
CHANCES THIS AFTERNOON. WHILE MOST OF THE THUNDERSTORM ACTIVITY
WILL REMAIN SOUTH OF THE AIRPORT. THUNDER IS CERTAINLY A
POSSIBILITY AROUND 22Z. WINDS REMAINING OUT OF THE EAST/NORTHEAST
AND BECOMING LIGHTER NEAR SUNSET.
OUTLOOK...
THU NIGHT/FRI...VFR.
SAT...VFR BUT INCREASING HIGH CLOUDS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
MPG/CLF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
630 AM CDT WED JUL 18 2012
.UPDATED FOR 12Z AVIATION DISCUSSION BELOW...
&&
.DISCUSSION.../ISSUED 409 AM CDT/
SFC-925MB FRONT DOWN ALONG THE IOWA BORDER THIS MORNING...BUT H85
FRONT BISECTS THE THE MPX CWA FROM THE MADISON AREA OVER TO CHIP
FALLS/EAU CLAIRE. HAVE BEEN SEEING VERY WEAK THETA-E ADVECTION
NORTH OF THIS BOUNDARY AND THAT COMBINED WITH PWATS UP AROUND 2
INCHES AND MUCAPE AROUND 1500 J/KG HAS ALLOWED FOR SCATTERED
CONVECTION NORTH OF THIS H85 BOUNDARY FROM NE SODAK OVER TO GREEN
BAY. THIS WAA REGIME IS IN RESPONSE TO A SHORTWAVE THAT CAN
ACTUALLY BE SEEN ON A RADAR MOSAIC...WITH A NICE SPIN IN THE
REFLECTIVITY DOWN AROUND YANKTON...SD. THE RAP HAS ALSO BEEN
SHOWING A NICE PV ANOMALY ACROSS ERN SODAK THAT HAS HELPED
GENERATE MORE WIDESPREAD CONVECTION THERE. AS WE GO THROUGH THE
DAY...BOUTS OF SCT CONVECTION WILL CONTINUE TO OCCUR THROUGH THE
MORNING WITHIN THE WEAK CORRIDOR OF H85 THETA-E ADVECTION FROM
MAINLY CENTRAL MN INTO CENTRAL WI. THE 18.05 HRRR REFLECTIVITY
FORECAST PROBABLY HAS THE RIGHT IDEA FOR THIS MORNING...JUST
DISPLACED A LITTLE TOO FAR NORTH. AS THE AFTERNOON ROLLS
AROUND...THE PV ANOMALY WILL BEGIN WORKING ACROSS THE SRN HALF OF
THE MPX AREA. HAVE MAINLY 40 TO 50 POPS WORKING ACROSS THE AREA
FROM WRN MN INTO WRN WI THOUGH TONIGHT AS THIS PV FEATURE MOVES
ACROSS. MAY NEED TO BUMP UP POPS MORE AS THIS UPPER FEATURE HAS
HAD LITTLE TROUBLE FORCING CONVECTION OVERNIGHT. AS FOR SVR
POTENTIAL WITH THIS ACTIVITY...LACK OF SHEAR COMBINED WITH
FREEZING LEVELS OVER 14K FEET WILL KEEP THE SVR POTENTIAL PRETTY
MINIMAL WITH THE MAIN THREAT BEING FROM GUSTS WINDS IF WE CAN GET
ROBUST ENOUGH STORMS TO RAPIDLY COLLAPSE.
BESIDE RECEIVING SOME MUCH NEEDED RAIN...THIS WAVE WILL ALSO
PROVIDE CLOUD COVER AND COOLER TEMPS ACROSS MOST OF THE CWA FOR
TODAY. THE ONLY EXCEPTION WILL BE ACROSS SRN MN. +28C 925MB TEMPS
WILL NOT BE TOO FAR AWAY FROM THE I-90 CORRIDOR...AND IF THEY DO
NOT SEE MUCH IN THE WAY OF CLOUD COVER BY THE AFTERNOON...THEN
WILL BE ANOTHER LOWER TO MIDDLE 90S DAY DOWN THERE. DEPENDING ON
CLOUD COVER DURATION...MAY HAVE SOME AREAS STAY IN THE 70S FOR
HIGHS TODAY...ESPECIALLY IN THE NORTHEAST SECTION OF THE
CWA...WHERE TEMPS THROUGH H85 WILL BE A BIT COOLER TO BEGIN WITH.
THESE COOLER TEMPS WILL CONTINUE INTO THURSDAY...FOR WRN WI AT
LEAST...AS STRONG NW FLOW SETS IN ALOFT BEHIND TODAYS SHORTWAVE.
FOR FRIDAY THROUGH TUESDAY...THE BIG PLAYER HERE WILL BE THE
STRONG UPPER RIDGE WE HAVE SEEN ALL SUMMER WAFFLING ACROSS THE
CONUS. BY THURSDAY...ANOTHER 595+DM H5 HIGH WILL BE BUILDING
ACROSS THE HIGH PLAINS WITH THE HEAT BUBBLE WE BEAT BACK SOME
TODAY RAPIDLY REBUILDING TO THE WEST. THIS H5 RIDGE WILL SLOWLY
SHIFT INTO THE CENTRAL PLAINS FROM THE WEEKEND INTO EARLY NEXT
WEEK. UP HERE...THE MPX CWA LOOKS TO BE SITTING NEAR THE NRN
PERIPHERY OF THE RIDGE. THE WARMEST DAYS OF THIS PERIOD LOOK TO BE
FRIDAY/SATURDAY AS THE NAM/ECMWF SHOW 594DM H5 HEIGHTS BUILDING UP
INTO CENTRAL MN INTO WRN WI. THE NAM IN PARTICULAR IS RATHER
AGGRESSIVE WITH WAA INTO THE AREA THESE DAYS...WITH ITS 925-850MB
TEMPS INDICATING ANOTHER ROUND OF UPPER 90S TO 102/3 TYPE HIGHS
BEING POSSIBLE BOTH DAYS. DID BUMP HIGHS UP SOME...ESPECIALLY FOR
FRIDAY...BUT MOST MODELS SHOW A NOCTURNAL CONVECTIVE SYSTEM FIRING
OFF TO THE NORTH FRI NIGHT...THAT MAY TRY TO LAY DOWN INTO NRN
SECTIONS OF THE MPX CWA SATURDAY. GIVEN THE UNCERTAINTIES WITH
CLOUD COVER FOR SATURDAY...WAS A BIT MORE CONSERVATIVE WITH HIGHS
THEN. DUE TO PROXIMITY TO UPPER RIDGE...THE MPX AREA WILL BE PRONE
TO ANY RING OF FIRE CONVECTION SATURDAY THROUGH MONDAY. BY
TUESDAY...BOTH THE ECMWF AND GFS CONTINUE TO SHOW A STRONGER COLD
FRONT SWEEPING ACROSS THE AREA...WHICH AT THIS POINT REPRESENTS
THE BEST CHANCES FOR RAIN AFTER TODAY. THIS FRONT ALSO LOOKS TO
PROVIDE ANOTHER 2 OR 3 DAY REPRIEVE FROM THE HEAT AS WELL.
&&
.AVIATION.../12Z TAF ISSUANCE/
THE COMPLEX OF SHOWERS AND THUNDERSTORMS OVER ERN SD WILL CONTINUE TO
EXPAND INTO WEST/CENTRAL MN THIS MORNING...AS A SHORTWAVE LIFTS
INTO THE AREA AND INTERACTS WITH THE BOUNDARY OVER SOUTHERN MN.
HAVE INCLUDED ASSOCIATED PERIODS OF SHOWERS AND
THUNDERSTORMS...ALONG WITH MVFR CIGS/VSBYS. EAST WINDS AROUND OR
JUST BELOW 10 KTS WILL PREVAIL TODAY...AND THEN DECREASE BELOW 5
KTS TONIGHT. THERE COULD BE SOME LIGHT FOG DEVELOPMENT AFTER 09Z
THU AS WELL.
MSP...A FLEETING SHRA CANNOT BE RULED OUT PRIOR TO 14Z...BUT THE
MAIN WINDOW OF TIME FOR SHRA/TS IS EXPECTED TO BE BETWEEN 15Z AND
20Z. PERIODS OF MVFR CIGS/VSBYS WILL BE POSSIBLE WITH THE
ACTIVITY. WHILE ISOLD SHOWERS APPEAR POSSIBLE THIS
AFTERNOON...ACTIVITY SHOULD WANE AFTER 21Z. EAST WINDS AROUND 10
KTS WILL PREVAIL TODAY...AND DECREASE BELOW 5 KTS AFTER 06Z...WHEN
LIGHT FOG FORMATION AND MVFR VSBYS APPEAR POSSIBLE.
OUTLOOK...
WED NIGHT/EARLY THU...CHC OF BR AND ASSOCIATED MVFR CIGS BETWEEN
08Z AND 12Z. THU/FRI...VFR. SAT...VFR BUT INCREASING HIGH CLOUDS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
MPG/LS
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1120 PM CDT THU JUL 19 2012
.SHORT TERM...
ISSUED AT 325 PM CDT THU JUL 19 2012
(TONIGHT)
`COLD` FRONT IS DRIFTING THROUGH THE NORTHERN PORTION OF THE CWFA
THIS AFTERNOON. SHORT-RANGE EXPLICIT MODELS SUCH AS THE HRRR... AND
NCEP 4KM WRF FIRE UP CONVECTION SOUTH OF THE STL METRO AREA ACROSS
THE EASTERN OZARKS WHERE LOW LEVEL CONVERGENCE IS MAXIMIZED ALONG A
PRE-FRONTAL TROF. WHILE THE RAP AND NAM DO HAVE SOME PRECIP AS FAR
NORTH AS THE I-70 CORRIDOR...I THINK ANY PRECIP THAT BREAKS OUT THAT
FAR NORTH WILL BE SPOTTY AND WEAK. PRECIP ACROSS THE OZARKS SHOULD
END BY LATE EVENING.
(FRIDAY-SATURDAY)
SOMEWHAT COOLER AIR WILL FILTER INTO EASTERN MISSOURI AND SOUTHERN
ILLINOIS FOR FRIDAY AND SATURDAY. MODELS ARE IN GOOD AGREEMENT THAT
850MB TEMPS WILL DROP DOWN TO THE 20-22C RANGE WHICH MIXES DOWN TO
THE LOW TO MID 90S. HAVE BASICALLY IGNORED THE COOL GFS GUIDANCE
AND STUCK VERY CLOSE TO PERSISTENCE AND THE NAM. SHOULD BE ABLE TO
KEEP HEAT INDEX VALUES BELOW 100 DEGREES BOTH DAYS...SO WILL LET THE
ADVISORY EXPIRE AS PLANNED.
CARNEY
&&
.LONG TERM...
ISSUED AT 325 PM CDT THU JUL 19 2012
(SUNDAY-THURSDAY)
MEDIUM RANGE GUIDANCE HAS BEEN VERY PERSISTENT IN BUILDING THE UPPER
LEVEL RIDGE BACK OVER THE AREA ON SUNDAY AND KEEPING IT OVER US
THROUGH MID-WEEK. 850MB TEMPS ON THE ECMWF RISE TO 24C-26C OVER THE
AREA AS THE THERMAL RIDGE BUILDS BACK OVER THE MIDWEST WITH A
VENGEANCE. EXPECT TEMPERATURES AOA 100 DEGREES FOR THE ENTIRE WEEK
WITH HEAT INDEX VALUES IN EXCESS OF 105. HEAT INDEX VALUES MAY BE A
BIT LOWER OVER THE EASTERN OZARKS DUE TO SLIGHTLY LOWER AMBIENT
TEMPERATURES AND LOWER DEWPOINTS SINCE THEY WILL BE FURTHEST FROM
THE THERMAL RIDGE AXIS. HAVE ISSUED AN EXCESSIVE HEAT WATCH FOR
MOST OF EASTERN MISSOURI AND SOUTHWEST ILLINOIS...BUT LEFT THE
EASTERN OZARKS OUT. MODELS TRY TO PRINT OUT SOME SPOTTY PRECIP HERE
AND THERE DURING THE AFTERNOON...BUT HAVE KEPT THE EXTENDED DRY DUE
TO THE PERSISTENT DROUGHT.
CARNEY
&&
.AVIATION...
ISSUED AT 1120 PM CDT THU JUL 19 2012
ISOLD -TSRA HAVE NOW MOVED WELL SOUTH OF THE ST. METRO TAF SITES.
NEXT CONCERN IS THE AREA OF CLOUDS WITH MVFR CIGS MOVING SOUTH INTO
CENTRAL ILLINOIS. CIG OF BKN041 HAS JUST MOVED INTO KUIN IN A PATCH
OF CLOUDS AHEAD OF THE MAIN BODY. HAVE ADDED A HIGH MVFR CIG AT
KUIN AROUND 09Z TO ACCOUNT FOR THE LOWER CIGS...BUT NOT SURE THAT
THEY WILL MAKE IT ALL THE WAY SOUTH TO THE ST. METRO TAF SITES.
HAVE ADDED SCT030 AT THE SITES STARTING 11-12Z TO ACCOUNT FOR THIS
POSSIBILITY. THEN MIXING SHOULD CAUSE ANY CLOUDS TO GO SCT BY MID
MORNING. OTHERWISE EXPECT DRY AND VFR CONDITIONS WITH NORTHERLY
WINDS SHIFT EASTERLY AFTER 00Z.
SPECIFICS FOR KSTL...THERE IS SOME SMALL CHANCE FOR MVFR CIGS TO
MOVE INTO KSTL FROM THE NORTH AROUND 12Z...BUT DO NOT HAVE HIGH
ENOUGH CONFIDENCE TO GO WITH ANY MORE THAN SCT AT THIS POINT. WILL
KEEP WITH A DRY AND VFR FORECAST AT THIS POINT WITH NORTHERLY
WINDS SHIFTING FROM THE EAST AFTER 00Z.
BRITT
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...EXCESSIVE HEAT WATCH FROM SUNDAY AFTERNOON THROUGH THURSDAY
EVENING FOR AUDRAIN MO-BOONE MO-CALLAWAY MO-COLE MO-
FRANKLIN MO-GASCONADE MO-JEFFERSON MO-KNOX MO-LEWIS MO-
LINCOLN MO-MARION MO-MONITEAU MO-MONROE MO-MONTGOMERY MO-
OSAGE MO-PIKE MO-RALLS MO-SHELBY MO-ST. CHARLES MO-ST.
LOUIS CITY MO-ST. LOUIS MO-WARREN MO.
IL...EXCESSIVE HEAT WATCH FROM SUNDAY AFTERNOON THROUGH THURSDAY
EVENING FOR ADAMS IL-BOND IL-BROWN IL-CALHOUN IL-CLINTON IL-
FAYETTE IL-GREENE IL-JERSEY IL-MACOUPIN IL-MADISON IL-
MARION IL-MONROE IL-MONTGOMERY IL-PIKE IL-ST. CLAIR IL-
WASHINGTON IL.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS BILLINGS MT
344 AM MDT FRI JUL 20 2012
.SHORT TERM...VALID FOR TDY AND SAT...
IT WILL REMAIN HOT THE NEXT TWO DAYS...BUT AT LEAST SLIGHT CHANCES
OF THUNDER ARE BEING THROWN BACK INTO THE MIX TOO THANKS TO ENERGY
DAMPENING THE HOT DOME OF HIGH PRESSURE ALOFT. THE 00 UTC GUIDANCE
IS IN GOOD AGREEMENT ON THIS IDEA...AND IT LINES UP WELL WITH MOST
OF THE GOING FORECAST...SO CONTINUITY RULED WITH THIS RELEASE.
THIS MORNING...MID- AND UPPER-LEVEL MOISTURE ADVECTION AND A 55 KT
250-HPA JET STREAK MOVING INTO CENTRAL MT MAY GENERATE SOME SHOWER
ACTIVITY ACROSS THE AREA. THE LAST FEW HRRR RUNS APPEAR TOO ROBUST
WITH THIS ACTIVITY SINCE THE BOUNDARY LAYER IS STILL RATHER DRY...
BUT RADAR IMAGERY AT 09 UTC SUGGESTS SLIGHT CHANCE POPS ARE NEEDED
EVEN FOR THE BILLINGS AREA.
THIS AFTERNOON AND EVENING...LOW CHANCES OF STORMS WILL EXIST OVER
THE WHOLE AREA AS LOW-LEVEL EASTERLY FLOW BECOMES ESTABLISHED. THE
00 UTC DETERMINISTIC MODELS ALL SUGGEST THAT MID-LEVEL LAPSE RATES
WILL ACTUALLY WEAKEN BY 18 UTC THOUGH...PERHAPS IN RESPONSE TO THE
SIMULATED MOISTURE ADVECTION AND EARLY-DAY SHOWER ACTIVITY. THE 21
UTC SREF ALSO SUPPORTS THIS NOTION...SO IT IS HARD TO DISCOUNT. IT
THUS APPEARS MLCAPE WILL BE LIMITED TO LESS THAN 1000 J/KG...WHICH
MAY LIMIT STORM COVERAGE AND INTENSITY. ISOLATED SEVERE STORMS ARE
STILL POSSIBLE IN SOUTHEASTERN MT THOUGH...WHERE PROBABILITIES FOR
STORM INITIATION WILL BE HIGHER IN CLOSE PROXIMITY TO A WEAK FRONT
AND HIGHER TERRAIN OVER NORTHEASTERN WY AND WESTERN SD...AND WHERE
0-6 KM BULK WIND SHEAR OF 40 TO 50 KT IS EXPECTED.
TONIGHT...A 35 KT 850-HPA LOW-LEVEL JET IS EXPECTED TO FORM ACROSS
SOUTHEASTERN MT...WHICH SHOULD PROVIDE FORCING FOR CONVECTION ATOP
A RETREATING MID-LEVEL FRONT. MUCAPE WILL BE ON THE ORDER OF 1000
J/KG BASED ON A NON-NAM CONSENSUS...SO SOME ORGANIZED UPDRAFTS MAY
OCCUR WELL AFTER SUNSET. THE SCENARIO IS WORTHY OF SOME 40 PERCENT
TYPE OF POPS IN CARTER AND FALLON COUNTIES THROUGH THE NIGHT. EVEN
SO...THE 00 UTC GFS AND NAM BOTH SHOW SOME WEAK 500-HPA SHORT WAVE
RIDGING OVER SOUTHEASTERN MT BEFORE 12 UTC...WHICH COULD SHUT DOWN
CONVECTION EARLIER THAN EXPECTED. THE 00 UTC 4 KM WRF NMM DOES NOT
HAVE ANYTHING TO DO WITH THAT POSSIBILITY THOUGH...AS IT CALLS FOR
RATHER ROBUST CONVECTION IN FAR SOUTHEASTERN MT ALL NIGHT.
ON SAT...A WEAK FRONT IS EXPECTED TO MOVE INTO EASTERN MT...BUT IT
LOOKS LIKE MIXING BEHIND THAT FEATURE WILL EXTEND TO 650 HPA. HIGH
TEMPERATURES WILL THUS EASILY EXCEED 95 F FOR MOST LOWER ELEVATION
LOCATIONS. MLCAPE IS EXPECTED TO EXCEED 2000 J/KG EAST OF THE WIND
SHIFT WITH THAT FRONT...WHICH COULD LINGER OVER SOUTHEASTERN MT...
SO SOME POPS FOR STORMS ARE AGAIN WARRANTED IN THAT AREA. NON-ZERO
SEVERE WEATHER PROBABILITIES WILL ALSO EXIST...BUT 00 UTC GUIDANCE
SUGGESTS 0-6 KM BULK SHEAR ONLY NEAR 30 KT...WHICH MAY BE MARGINAL
FOR MORE THAN A TRANSIENT RISK WITH ANY STORMS THAT FORM. SCHULTZ
.LONG TERM...VALID FOR SUN...MON...TUE...WED...THU...
CRITICAL FIRE WEATHER CONDITIONS EARLY NEXT WEEK CONTINUE TO BE
THE PRIMARY CONCERN FOR THE EXTENDED PERIOD. SOUTHWEST UPPER FLOW
CONTINUES INTO MONDAY BETWEEN HIGH PRESSURE ACROSS THE PLAINS AND
APPROACHING UPPER LOW IN THE PACIFIC NORTHWEST. DISTURBANCES IN
THE FLOW WILL BE ENOUGH FOR A MENTION OF ISOLATED STORMS INTO
MONDAY. PACIFIC NORTHWEST UPPER LOW EXPECTED TO TRACK OFF TO OUR
NORTH TUESDAY THROUGH WEDNESDAY WITH ASSOCIATED COLD FRONTAL
PASSAGE ON TUESDAY. MONDAY SHOULD BE THE WARMEST DAY OF NEXT WEEK
IN A PREFRONTAL ENVIRONMENT. BUMPED TEMPERATURES UP JUST A BIT
MORE FOR MONDAY. BRISK SOUTHEAST WINDS OVER EASTERN MONTANA ARE
EXPECTED AHEAD OF THE FRONT WITH GUSTY WEST WINDS BEHIND IT
LEADING TO THE POTENTIAL FOR DANGEROUS FIRE WEATHER.
MIDWEEK WILL SEE A RELATIVE COOL DOWN WITH GRADUAL WARMING AGAIN
LATE IN THE WORK WEEK. RAISED TEMPS A BIT FOR THURSDAY AND FRIDAY
NEXT WEEK BASED ON GFS AND ECMWF PROGGED THERMAL RIDGE. ECMWF
HINTS AT A STRONGER WAVE OUT OF THE SOUTHWEST NEXT SATURDAY AS
DOES THE GFS TO A LESSER EXTENT. THIS REPRESENTS THE BEST CHANCE
OF DECENT WIDESPREAD RAINFALL ON OUR HORIZON. BT
&&
.AVIATION...
WIDELY SCATTERED SHOWERS WILL SPREAD OVER THE KLVM AREA EARLY THIS
MORNING AS WELL AS THE NEARBY MOUNTAINS....BUT CONDITIONS SHOULD
REMAIN VFR DUE TO HIGH BASES. A FEW TSTMS ARE POSSIBLE ACROSS THE
ENTIRE AREA FRIDAY AFTER 18UTC. THESE WILL BE HIGH BASED AND THUS
VFR WILL PREVAIL...THOUGH LOCAL MVFR IS A POSSIBILITY NEAR EITHER
KMLS OR KBHK. IN ADDITION...ERRATIC WIND GUSTS CAN BE EXPECTED
NEAR ANY STORMS THAT DEVELOP THIS AFTERNOON AND EVENING. BT
&&
.PRELIMINARY POINT TEMP/POPS...
TDY SAT SUN MON TUE WED THU
-------------------------------------------------------
BIL 095 066/096 064/096 066/099 064/092 061/092 061/095
2/T 21/U 11/U 22/T 20/U 00/U 00/U
LVM 095 054/095 054/094 055/096 054/090 054/091 052/093
2/T 22/T 22/T 22/T 20/B 01/U 11/U
HDN 098 062/097 061/098 067/101 065/096 061/095 062/098
2/T 21/U 11/U 22/T 20/U 11/U 00/U
MLS 097 070/100 069/099 070/104 069/095 064/093 064/098
2/T 21/U 11/U 22/T 30/B 11/U 10/U
4BQ 097 064/099 064/098 067/100 068/094 061/093 063/098
3/T 32/T 21/B 22/T 21/U 11/U 10/U
BHK 096 064/097 065/096 066/097 067/092 064/089 061/094
2/T 42/T 31/B 22/T 32/T 22/T 10/U
SHR 095 060/096 059/096 061/098 062/093 058/093 057/096
3/T 21/B 21/B 21/B 20/B 11/U 11/U
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
149 AM EDT FRI JUL 20 2012
.SYNOPSIS...
AN UPPER SHORT WAVE...COMBINED WITH ABUNDANT MOISTURE AND DIURNAL
HEATING PROVIDE UNSTABLE CONDITIONS THROUGH FRIDAY. A COLD FRONT WILL
MOVE THROUGH THE AREA FRIDAY. HIGH PRESSURE BUILDS IN FRIDAY NIGHT
INTO SATURDAY.
&&
.NEAR TERM /THROUGH TODAY/...
UPDATE...
MORE CONVECTION TRIGGERED BY A SHORT WAVE ALOFT TO PUSH INTO THE
SOUTHEAST OHIO COUNTIES IN THE NEXT HOUR OR SO. LOCAL MODELS
CONTINUE TO INDICATE INITIATION THROUGH DAWN...AND KEEP THE POPS
RELATIVELY HIGH.
PREVIOUS DISCUSSION...
AN APPROACHING UPPER LEVEL TROUGH WILL PROVIDE ENOUGH
FORCING OVER A HIGH CAPE...HIGH PRECIPITABLE WATER ENVIRONMENT
THROUGH FRIDAY.
SEVERAL BANDS OF THUNDERSTORMS ARE EXPECTED TO DEVELOP AND MOVE
FROM THE WEST THIS EVENING AND LATER TONIGHT. HPC QPF GUIDANCE
SUGGEST NEAR 3 INCHES MAINLY NORTHERN WV PANHANDLE...SOUTH ALONG
THE OH RIVER INTO PKB THROUGH 12Z FRIDAY.
EXPECT HEAVY DOWNPOURS WITH EVERY SINGLE STORM. MODELS SHOW PRECIPITABLE
WATER EXCEEDING 2 INCHES THROUGH THIS AFTERNOON THROUGH FRIDAY.
THE NAM AND HPC SUGGEST A STRONGER SHOT OF PRECIPITATION OVERNIGHT
TONIGHT. A MODERATE RISK FOR EXCESSIVE RAINFALL STILL IN EFFECT FROM
HPC THROUGH 00Z SATURDAY. DUE TO YESTERDAYS RAINFALL AMOUNTS
MEASURED BY RAIN GAGE...BETWEEN 0.5 TO 1.8 INCHES ACROSS NORTH
CENTRAL WV...WHILE RADAR STORM TOTALS...ALTHOUGH
OVERESTIMATED...SHOWED HIGHER AMOUNTS AWAY FROM GROUND
GAGES...GROUNDS ARE NEARLY SATURATED. BESIDES THESE AREAS ARE MORE
PRONE TO FLOODING. THEREFORE...KEPT FLASH FLOOD WATCH FOR SEVERAL
COUNTIES ACROSS THE CENTRAL AND NORTH CENTRAL WV...INCLUDING
ATHENS COUNTY IN SOUTHEAST OH.
ADJUSTED POPS CLOSER TO THE HRRR PER BETTER AGREEMENT ON LACK OF
AFTERNOON CONVECTION...WHILE OTHER MESO AND SYNOPTIC MODELS
OVERDUE PCPN. A DISORGANIZED MCS TYPE FEATURE CONTINUES TO PRODUCE
BANDS OF THUNDERSTORMS ACROSS OH. THE FIRST BAND HAVE REACHED
SOUTHEAST OH BY MID AFTERNOON...AND IS EXPECTED TO MOVE EAST TO
AFFECT THE FLASH FLOOD WATCH AREA EARLY THIS EVENING. ADDITIONAL
BAND OF STORMS ARE EXPECTED TO DEVELOP OVERNIGHT POSING THE THREAT
FOR SIGNIFICANT RAIN ACCUMULATIONS.
MOIST...WARM...AND HIGH SFC CAPE ENVIRONMENT REMAIN IN PLACE ON
FRIDAY...WHILE A SECONDARY VORT MAX MOVES ACROSS ASSOCIATED WITH
THE AFOREMENTIONED UPPER TROUGH. THEREFORE...KEPT HIGH LIKELY POPS
THROUGH THE END OF THE PERIOD FOCUSING THE EASTERN HALF OF THE
AREA.
WENT CLOSER TO THE LAV/MAV NUMBERS THROUGH THE PERIOD.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
BY FRIDAY EVENING THE COLD FRONT IS EXPECTED TO BE NEAR THE OHIO
RIVER. MEANWHILE BEST LARGE SCALE FORCING FOR ASCENT IS LOCATED OVER
THE NORTHEAST PART OF FORECAST AREA. IN ADDITION...A VORT MAX WILL
BE PUSHING SE-WARD ACROSS NORTHERN WV...WITH LIFT ASSOC WITH IT OUT
AHEAD ACROSS NE PART OF CWA. FINALLY...WITH COLD FRONT MOVING INTO
NORTHERN PART OF AREA AND GOOD LLVL MOISTURE CONVERGENCE
NOTED...SHOWERS/STORMS A GOOD BET TO CONTINUE ACROSS MUCH OF THE
AREA WITH THE HIGHEST POPS WEIGHTED ACROSS NE ZONES BY THE EVENING
HOURS. THOUGH GREATEST COVERAGE IS EXPECTED NORTHEAST...BETTER
CHANCE AT STRONG TO SVR WX APPEARS TO BE ACROSS SOUTHERN AND WESTERN
PARTS OF FORECAST AREA WHERE MARGINAL SHEAR COINCIDES BEST WITH
HIGHEST AXIS OF INSTABILITY. HEAVY DOWNPOURS AND STRONG WINDS
CONTINUE TO BE THE PRIMARY HAZARDS MAINLY BTWN 00Z-03Z. DCAPE VALUES
OF BTWN 500J-800J WITH SFC-MIDLEVEL THETA-E DIFFERENCES OF ~25C
PARTICULARLY ACROSS THE WEST ZONES INDICATE BETTER POTENTIAL FOR
STRONG DOWNBURST WINDS IN THESE LOCALES. SHOWERS/STORMS WILL PUSH
EASTWARD AND SOUTHWARD OVERNIGHT WITH DIMINISHING INTENSITY WITH
LOSS OF INSTABILITY.
BY SATURDAY MORNING COLD FRONT SHOULD BE LOCATED ACROSS THE
SOUTHEAST PART OF CWA WITH LARGE SCALE FORCING FOR SUBSIDENCE
OVERSPREADING THE AREA FROM NW/SE. BEST DEEP LAYER MOISTURE WILL BE
LOCATED NEAR AND AHEAD OF THE FRONT AND THUS WILL CONTINUE SLIGHT
CHANCE/LOW CHANCE POPS IN THIS AREA. FRONTAL ZONE WILL STALL TO THE
SOUTH AND SOUTHEAST ALONG WITH MOISTURE WITH CONTINUED CHANCE OF
SHOWERS AND THUNDERSTORMS PRIMARILY FAR EAST AND SOUTH THE REMAINDER
OF SATURDAY. WILL CONTINUE PRIMARILY SLIGHT CHANCE POPS SUNDAY AGAIN
PRIMARILY FOR FAR EASTERN AND SOUTHERN ZONES AS INSTABILITY AND LLVL
MOISTURE REMAIN ENTRENCHED IN THOSE AREAS.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
OPERATIONAL EXTENDED NWP CONTINUES TO BE IN REASONABLY GOOD
AGREEMENT REGARDING GENERAL FEATURES DURING THIS PERIOD...DEPICTING
A STRENGTHENING UPPER LEVEL RIDGE OVER THE CENTRAL CONUS/HIGH PLAINS
REGION WITH ANOTHER OFF SE ATLANTIC COAST...WITH WNW/NW FLOW ALOFT
OVER FORECAST AREA THROUGH MUCH OF THE PERIOD. AS UPPER HIGH
ATTEMPTS TO BUILD EASTWARD...MAX TEMPS WILL REMAIN SLIGHTLY ABOVE
NORMAL LEVEL WITH READING CONTINUING IN THE UPPER 80S/LOWER 90S
LOWLAND AREAS. EXTENDED NWP AND ENSEMBLES ALSO IN DECENT AGREEMENT
WITH MOVING A FRONT INTO THE AREA TUESDAY AND WILL GO AHEAD AND
RAISE POPS INTO THE LOW CHANCE CATEGORY FOR THIS PERIOD. DIFFERENCES
ARISE HOWEVER WITH THE HANDLING OF THIS FRONT HOWEVER AND WILL USE A
BLEND WITH A LEANING TOWARDS THE EC WITH REGARD TO DAYS 6-7. TEMPS
WILL GENERALLY CONTINUE IN THE UPPER 80S/LOWER 90S FOR THE
PERIOD...PERHAPS A FEW DEGREES COOLER TUESDAY WITH THE FRONT/MORE
CLOUDS IN AREA.
&&
.AVIATION /05Z FRIDAY THROUGH TUESDAY/...
SURFACE LOW RIDING INTO THE MIDDLE OHIO VALLEY COUPLED WITH
DISTURBANCES ALOFT AND PLENTY OF MOISTURE MAKES FOR A COMPLEX
AVIATION FORECAST TONIGHT. DESPITE CLOUD COVER...FOG HAS DEVELOPED
AT CRW...WITH IFR TO LIFR CEILINGS AT PKB AND EKN. WITH CONVECTION
CONTINUING OVERNIGHT...EXPECT OBSERVATIONS TO BOUNCE...REDUCING
OVERALL CONFIDENCE IN THE FORECAST. THESE CEILINGS COULD LIFT WITH
ANY RAIN...AS WOULD THE VISIBILITY AT CRW UNDER SIMILAR
CONDITIONS. MORE CONVECTION EXPECTED DURING THE DAY FRIDAY BEFORE
ENDING LATE FRIDAY EVENING AND FRIDAY NIGHT. TAFS WARRANT PLENTY
OF VCTS/CB DURING THE LATE MORNING AND AFTERNOON HOURS TODAY.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z SATURDAY...
FORECAST CONFIDENCE: LOW TO MEDIUM.
ALTERNATE SCENARIOS: TIMING AND COVERAGE OF THUNDERSTORMS AND ANY
CATEGORY CHANGES MAY VARY. MORNING FOG COVERAGE MAY VARY.
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.
DATE FRI 07/20/12
UTC 1HRLY 02 03 04 05 06 07 08 09 10 11 12 13
EDT 1HRLY 22 23 00 01 02 03 04 05 06 07 08 09
CRW CONSISTENCY H H H H H H H H H M M H
HTS CONSISTENCY H H H H H H H H M M M H
BKW CONSISTENCY M M H H H H H H H H H M
EKN CONSISTENCY H H H H H M M M M M L M
PKB CONSISTENCY H H H H H H H H H H H H
CKB CONSISTENCY M M M M H H H H H H H H
AFTER 06Z SATURDAY...
IFR FOG POSSIBLE EARLY SATURDAY MORNING.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...JS/ARJ/50
NEAR TERM...ARJ/26
SHORT TERM...50
LONG TERM...50
AVIATION...26
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
418 AM CDT FRI JUL 20 2012
.DISCUSSION...
RADAR AND SATELLITE LESS ACTIVE THAN LAST NIGHT. HIGH PRESSURE
RIDGE ALOFT OVER SE TX TODAY AND TOMORROW BRINGING SOME
SUBSIDENCE. HAVE REDUCED POPS FOR TODAY DOWN TO 20 PERCENT
AREAWIDE FOR THE AFTERNOON. WARMING TEMPERATURES ALOFT FROM
SUBSIDENCE BETWEEN 900-850MB SHOULD HELP CAP SOME CONVECTION AND
RESULT IN LESS COVERAGE THAN YESTERDAY. HRRR REFLECTIVITY FIELD
FORECAST COVERAGE IS VERY SPARSE AND NEAR COAST THIS AFTERNOON.
STILL SEEING MOIST PWAT AIR OVER SE TX FCST BY GFS IN THE 1.8 TO
NEAR 2.0 INCH RANGE. GFS FCST SOUNDINGS INDICATE CONVECTIVE TEMPS
IN THE MID 90S WHICH WILL BE REACHED AT KIAH LATE IN THE AFTN.
OTHERWISE HOT AND HUMID WITH AFTERNOON HEAT INDICES IN THE 100-105
RANGE.
UPPER DISTURBANCE ROTATING AROUND THE LARGER UPPER HIGH OVER KS/OK
WILL APPROACH THE CWA BY SUNDAY. GFS DOES HAVE CONVECTIVE FEEDBACK
LOOKING PCPN BULLSEYE APPROACHING SE TX ON SAT NIGHT/SUNDAY
MORNING. OTHER MODELS ARE DRY. THIS FEATURE SEEMS TO ORIGINATE
FROM CONVECTION OCCURRING EARLIER TONIGHT IN TENNESSEE. NOT OUT OF
THE QUESTION THAT SOMETHING WILL ROTATE INTO OUR AREA...AS A
RESULT I INCLUDED SLIGHT CHC TSRA FOR OVERNIGHT HOURS SAT INTO
SUNDAY MORNING. WILL NEED TO WATCH THIS FOR POSSIBLE CHANGES
DEPENDING UPON LATER OBS AND MODEL TRENDS. THIS
TROUGH/DISTURBANCE ROTATES THROUGH SE TX QUICKLY AND IS IN WEST TX
BY MONDAY NIGHT. TUTT LOW OVER CUBA/JAMAICA TONIGHT MOVES TOWARDS
THE NW GULF OF MEXICO BY EARLY NEXT WEEK...LOW POPS ARE THE RESULT
IN THE EXTENDED FORECAST SO FAR.
TENDED WARMER THAN GFS MOS GUIDANCE AGAIN THIS PACKAGE FOR MAX
TEMPS. OPERATIONAL MOS AGAIN ON THE COOL SIDE OF THE ENSEMBLES.
ETA MOS/ECM MOS ARE WARMER AND HAVE BEEN PERFORMING BETTER SO OUR
CONTINUED WARMER THAN GUIDANCE TREND FOR THE NEXT FEW DAYS SEEMS A
GOOD IDEA.
ZONES MAY BE A TAD LATE DUE TO SOME AWIPS ISSUES EARLIER THIS
MORNING...BUT NOT TOO LATE. 04
&&
.MARINE...
LIGHT SOUTHWEST TO WEST WINDS WILL CONTINUE TODAY ACROSS THE COASTAL
WATERS AS HIGH PRESSURE CONTINUES TO BUILD ACROSS HE GULF OF
MEXICO. ISOLATED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO CONTINUE
THROUGH EARLY NEXT WEEK AS A TUTT APPROACHES FROM THE EAST. 38
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 97 77 98 76 97 / 20 10 10 10 20
HOUSTON (IAH) 95 77 96 76 93 / 20 20 20 20 20
GALVESTON (GLS) 92 81 91 81 92 / 20 20 20 20 20
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...04
AVIATION/MARINE...38
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
318 PM CDT WED JUL 18 2012
.SHORT TERM...
AGAIN...CONSIDERABLE QUESTIONS REMAIN AS TO WHETHER OR NOT
CONVECTION WILL BE ABLE TO DEVELOP ACROSS THE FORECAST AREA OR NOT.
UPPER LOW CONTINUES TO SPIN JUST SOUTHEAST OF THE BIG BEND OVER THE
RIO GRANDE AND THERE REMAINS SOME ENHANCED MOISTURE OVER THE REGION.
MODELS REMAIN ALL OVER THE PLACE WITH TIMING...COVERAGE...AND HOW
LONG STORMS MAY STAY AROUND /IF/ THEY DEVELOP. HRRR HAS BEEN FAIRLY
CONSISTENT WITH DEVELOPING ISOLATED TO SCATTERED STORMS ALONG AND
EAST OF THE CAPROCK WHILE THE NAM AND TTU WRF ARE DRY. CU FIELD ON
VISIBLE SATELLITE IS A BIT MORE EXTENSIVE THAN THIS TIME YESTERDAY
BUT TAKING A LOOK OUTSIDE SHOWS LITTLE VERTICAL EXTENT FOR NOW.
RADAR IS SHOWING SOME RETURNS ACROSS THE SOUTHWESTERN TEXAS
PANHANDLE INTO EASTERN NEW MEXICO BUT EVEN THESE ARE DISSIPATING
FAIRLY FAST. WILL KEEP THE FORECAST DRY FOR TONIGHT BUT WILL NEED
TO WATCH THROUGH THE LATE AFTERNOON INTO THE EVENING. TEMPERATURES
WILL BE FAIRLY SIMILAR TO TODAY AND THIS MORNING FOR HIGHS AND LOWS
TOMORROW RESPECTIVELY.
JORDAN
&&
.LONG TERM...
UA RIDGE ACROSS COLORADO WILL AMPLIFY AND SHIFT NE TO ACROSS THE
CENTRAL PLAINS ON FRIDAY...AND PERSIST THERE THROUGH THE WEEKEND.
THE MONSOONAL MOISTURE WILL GET NUDGED WEST TO CENTRAL/WESTERN NEW
MEXICO. LARGE SCALE SUBSIDENCE WILL MITIGATE STORM POTENTIAL AND
SLOWLY INCREASING THICKNESS VALUES WILL PROMOTE WARMING TEMPS /UPPER
90S ON THE CAPROCK TO LOWER TRIPLE DIGITS OFF THE CAPROCK/. WILL
NEED TO KEEP AN EYE ON A WEAKNESS/UA IMPULSE ROUNDING THE SOUTHERN
PERIPHERY OF THE SAID RIDGE...AND MOVING ACROSS THE SOUTHERN
PLAINS FRIDAY EVENING/NIGHT. THUS FAR...FORECAST MODELS ARE VOID
OF PRECIP GIVEN A MID LEVEL CAPPING INVERSION AND THIS IMPULSE
APPEARING RELATIVELY WEAK. EARLY NEXT WEEK...BOTH THE GFS AND
ECMWF HINT AT A PACIFIC UA LOW PROPAGATING ENE ACROSS NORTHERN
IDAHO/SOUTHERN ALBERTA. THIS WILL ENCOURAGE THE CENTER OF THE UA
RIDGE TO TRANSLATE SE TO THE SERN CONUS...WHERE IT IS PROGGED TO
REMAIN THROUGH MID-WEEK. AS A RESULT...THE MONSOONAL MOISTURE
PLUME MAY HAVE THE OPPORTUNITY TO NEAR THE WESTERN ZONES.
CONCURRENTLY...AN EASTERLY WAVE IS SHOWN TO MOVE ACROSS THE THE FA
TUESDAY. THE GFS AND ECMWF SOLUTIONS EXHIBIT RATHER LIGHT QPF JUST
EAST AND SE OF THE CWA. WILL NEED TO ANALYZE FUTURE MODEL RUNS TO
SEE IF THIS WAVE WILL TURN OUT TO BE EVEN STRONGER THAN CURRENTLY
INDICATED...AND THUS CREATE CHANCES FOR PRECIP. ATTM...A SILENT
POP FORECAST WILL ENSUE.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 64 94 66 93 67 / 10 0 0 10 10
TULIA 66 94 67 95 68 / 10 0 0 10 10
PLAINVIEW 66 94 68 94 69 / 10 0 0 10 10
LEVELLAND 66 93 66 94 69 / 10 0 0 10 10
LUBBOCK 71 94 68 96 70 / 10 0 0 10 10
DENVER CITY 67 91 66 94 68 / 10 0 0 10 10
BROWNFIELD 67 92 67 95 69 / 10 0 0 10 10
CHILDRESS 71 100 73 101 73 / 10 0 0 10 10
SPUR 70 96 71 98 72 / 10 0 0 10 10
ASPERMONT 73 98 74 101 74 / 10 0 0 10 10
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
14/29
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
1140 AM EDT FRI JUL 20 2012
.UPDATE...
HAVE MADE SEVERAL MINOR TWEAKS TO GRIDS THIS MORNING...MOSTLY TO
ACCOUNT FOR HOURLY TRENDS WITH TEMPS DEWPOINTS AND POPS. SPC STILL
HAS MOST OF THE AREA IN A SLIGHT RISK FOR DAY1...AND POPS ACROSS
NORTH AND CENTRAL GEORGIA REMAIN VERY HIGH THIS AFTERNOON TO
ACCOUNT FOR CONVECTIVE DEVELOPMENT. THE CONCERN IS THAT...WITH THE
EXCEPTION OF THE MOST RECENT HRRR RUNS...NONE OF THE HIRES MODELS
HAD THE MCS REMNANTS LASTING SO LONG THIS MORNING. CONDITIONS ARE
PRETTY STABLE ACROSS NORTH GEORGIA RIGHT NOW WITH CAPES BELOW 500
IN THE RAIN-COOLED AIRMASS. HOWEVER...BEHIND THE CIRRUS SHIELD...
TEMPS ARE ALREADY STARTING TO INCREASE AND AT AFD TIME AM STARTING
TO SEE CONVECTION FIRE NEAR CHA. THINK THAT IN THE END THE
INSTABILITY WILL CATCH UP. 12Z KFFC MODIFIED SOUNDING WITH LOWER
70S DEWPOINTS AND A HIGH IN THE UPPER 80S GIVES OVER 3000 J/KG
SBCAPE SO AT THIS POINT STILL EXPECT NUMEROUS SHOWERS AND
THUNDERSTORMS TO DEVELOP WITH SOME POSSIBLY SEVERE. POPS MAY
ACTUALLY NEED TO BE INCREASED INTO THE AFTERNOON ONCE WE GET A
HANDLE ON LOCATION AND MOVEMENT.
TDP
&&
.PREV DISCUSSION... /ISSUED 741 AM EDT FRI JUL 20 2012/
SHORT TERM /TODAY THROUGH SATURDAY/...
/ISSUED AT 406 AM EDT FRI JUL 20 2012/
INITIAL CONCERN IS THE CONVECTIVE COMPLEX (MCS) SPREADING SOUTHWARD
FROM TN THIS MORNING. REGIONAL RADARS...CLOUD TOP TEMPERATURES NOTED
ON SATELLITE AND LIGHTNING DATA ALL SUGGEST THE STRONGER STORMS WILL
PUSH INTO NORTH AL... WITH A WEAKENING TREND NOTED FOR CONVECTION
MOVING INTO NORTH GA. THEREFORE...EXPECT MAINLY SHOWERS TO PUSH
ACROSS NORTH GA THIS MORNING...TO INCLUDE METRO ATLANTA...BEFORE
DISSIPATING. HOWEVER...CANNOT RULE OUT A THUNDERSTORM OR TWO WITH
THIS ACTIVITY...SO WILL MENTION A SLIGHT CHANCE OF THUNDER THROUGH
THE MORNING HOURS. THE GREATER THUNDERSTORM THREAT WILL OCCUR DURING
AFTERNOON HEATING AS AN ACTIVE UPPER TROUGH INTERACTS WITH A MOIST
(NEAR 2 INCH PW`S) AND UNSTABLE AIR MASS (1500-2500 J/KG CAPE) TO
PRODUCE SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS THIS
AFTERNOON AND EVENING. REMNANT OUTFLOW BOUNDARIES FROM THIS
MORNING`S MCS SHOULD HELP PROVIDE A FOCUS FOR STORM DEVELOPMENT...
AND THIS SHOULD OCCUR MAINLY OVER NORTH GA WHERE BOUNDARIES SHOULD
BE LINGERING. A SLIGHT INCREASE IN VERTICAL WIND SHEAR FROM A
STRENGTHENING SW MID LEVEL FLOW AHEAD OF A COLD FRONT PUSHING INTO
TN TODAY COULD AID IN STRONG TO SEVERE STORM DEVELOPMENT...
ESPECIALLY IF ENHANCED BY WEAK DISTURBANCES TRAVERSING THE UPPER
TROUGH TODAY. SPC HAS PLACED NORTH GA IN A SLIGHT RISK TODAY...
MAINLY NORTH OF A HAMILTON TO MONTICELLO TO WASHINGTON LINE. THE
PRIMARY THREAT WILL BE DAMAGING WIND GUSTS... BUT ALSO EXPECT
FREQUENT LIGHTNING...HEAVY RAIN AND SMALL HAIL WITH THE STRONGER
STORMS. ANY SLOW MOVING STORMS WILL PRODUCE LOCALLY HEAVY RAIN...
AND COULD RESULT IN BRIEF LOCALIZED FLASH FLOODING. MODELS AGREE ON
STALLING THE COLD FRONT OVER TN TONIGHT... THEN SAGGING THE FRONT
INTO NORTH GA ON SATURDAY WHERE IT LIKELY LINGERS BEFORE PUSHING
BACK NORTH ON SUNDAY. WILL CONTINUE TO SHOW A SLIGHT CHANCE OF
THUNDER OVERNIGHT... WITH LIKELY POPS WARRANTED AGAIN ON SATURDAY AS
THE ACTIVE UPPER TROUGH INTERACTS WITH THE FRONTAL BOUNDARY.
INCREASING CLOUDS AND CONVECTIVE ACTIVITY SHOULD HOLD DAYTIME HIGHS
DOWN INTO THE 80S FOR MOST AREAS TODAY AND AGAIN ON SATURDAY. HAVE
LEANED TOWARD A MAV AND MET BLEND THROUGH THE SHORT TERM AS MAV
LOOKED A BIT WARM AND MET COOL FOR HIGHS. THE LOWS WERE VERY CLOSE
AND LOOKED REASONABLE.
39
LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
/ISSUED AT 406 AM EDT FRI JUL 20 2012/
FRONTAL BOUNDARY WHICH SAGS OVER GA SAT WILL BEGIN TO PUSH BACK
NORTHWARD SAT NIGHT AS BERMUDA LIKE RIDGE BUILDS OFF THE GA/CAROLINA
COAST. THE BOUNDARY KEEPS A DECENT AMOUNT OF MOISTURE AND A FOCUSING
MECHANISM OVER THE AREA THROUGH MONDAY AFTERNOON BEFORE DIMINISHING
UNDER THE BUILDING RIDGE. SHOULD CONTINUE TO SEE A MOSTLY DIURNAL
CONVECTIVE TREND IN THE EXTENDED AS MOISTURE FROM THE GULF ROTATES
UP INTO THE AREA UNDER THE SURFACE RIDGE THROUGH DAY 7. EVEN WITH
THE HIGH IN PLACE...PLENTY OF LOW LEVEL MOISTURE WILL SUPPORT
DIURNAL CONVECTION EACH DAY. FORECAST PRECIPITABLE WATER VALUES
STILL SHOWING NEAR 2.0 INCH VALUES THROUGH THE MIDDLE OF NEXT
WEEK...AND WITH K-INDEX VALUES IN THE MID TO UPPER 30S...HEAVY RAIN
STILL REMAINS A THREAT. WIDESPREAD 1-1.25 INCHES ARE EXPECTED
THROUGH SUNDAY AFTERNOON...WITH LOCALLY HEAVIER AMOUNTS ASSOCIATED
WITH AREAS OF MODERATE TO STRONG CONVECTION. BY WEDNESDAY...LOW
PRESSURE DEEPENING OVER THE CANADIAN MARITIMES WILL DRAG ANOTHER
FRONTAL BOUNDARY THROUGH THE MID ATLANTIC STATES...WITH TROUGH
EXTENDING INTO NORTH GEORGIA. THE MODELS DO DIFFER A BIT ON JUST HOW
FAR SOUTH THIS FRONTAL BOUNDARY MOVES SO WILL CONTINUE WITH
DIURNALLY DRIVEN CHANCE POPS THROUGH DAY 7.
AS FOR TEMPERATURES...THINGS SHOULD BE A BIT COOLER THIS WEEKEND
WITH HI TEMPS IN THE 80S TO LOW 90S DUE TO THE FRONTAL BOUNDARY AND
RAIN. TEMPS WILL BEGIN TO REBOUND MONDAY THROUGH WEDNESDAY WITH
TEMPS BACK INTO THE MID 90S BY WED/THU.
01
AVIATION...
12Z UPDATE...
IFR CIGS WILL PERSIST UNTIL AROUND 13-14Z...THEN A LARGE AREA OF
CONVECTION OVER NW GA SPREADS IN OVER THE ATLANTA AREA TAF SITES...
RESULTING IN TEMPO -SHRA/-TSRA AROUND 13-16Z BEFORE THIS CONVECTION
GRADUALLY DISSIPATES THROUGH 17Z. THE AIR MASS WILL TAKE SOME TIME
TO DESTABILIZE AGAIN... BUT DO EXPECT OUTFLOWS FROM MORNING
CONVECTION TO HELP SPARK ADDITIONAL TSRA DEVELOPMENT AROUND 22-02Z
TODAY. MODELS AGREE ON IFR/MVFR CIGS DEVELOPING EARLY SAT MORNING AT
MOST TAF SITES...SO WILL CONTINUE TO SHOW MVFR CIGS BY 09Z SAT AT
ATL. EXPECT A WSW WIND AT 8-10KTS TO PREVAIL TODAY...THEN BACK MORE
SOUTHERLY LATER THIS EVENING AT 4-6KTS...BUT SHOULD STAY JUST WEST
OF SOUTH OVERNIGHT. IFR/MVFR CIGS SHOULD SCT BY 15Z SAT.
//ATL CONFIDENCE...12Z UPDATE...
MEDIUM CONFIDENCE ON TIMING OF -TSRA THIS MORNING...THEN
REDEVELOPMENT LATER TODAY. MEDIUM TO HIGH CONFIDENCE ALL OTHER
ELEMENTS.
39
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 88 72 84 70 / 70 60 60 40
ATLANTA 88 72 84 70 / 90 60 60 40
BLAIRSVILLE 84 69 82 66 / 70 60 60 40
CARTERSVILLE 89 71 85 70 / 80 60 60 40
COLUMBUS 89 73 88 72 / 70 50 60 30
GAINESVILLE 87 72 85 70 / 90 60 60 40
MACON 90 73 89 71 / 70 50 60 30
ROME 89 72 89 72 / 100 60 50 30
PEACHTREE CITY 88 71 85 70 / 70 60 60 40
VIDALIA 90 73 90 74 / 70 40 60 20
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1038 AM EDT FRI JUL 20 2012
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
ISSUED AT 356 AM EDT FRI JUL 20 2012
AS A COLD FRONT AND WEAK SURFACE LOW DEPART THE AREA TODAY...A
WEAK SHORTWAVE WILL TRAVERSE THE REGION. THIS WILL HAVE A SMALL
CHANCE OF SPARKING AN ADDITIONAL SHOWER OR TWO THIS MORNING BEFORE
DRY WEATHER RETURNS TO THE FORECAST THROUGH THE WEEKEND.
ADDITIONALLY...SKIES WILL BE MOSTLY CLOUDY THROUGH THE FIRST HALF
OF THE DAY AS STRATOCUMULUS BUILDS INTO THE AREA IN THE CYCLONIC
FLOW. THIS WILL ALSO HELP KEEP TEMPERATURES DOWN TODAY...WITH SOME
AREAS STRUGGLING TO EVEN REACH THE 80 DEGREE MARK...A MAJOR SHIFT
FROM RECENT RECORD BREAKING HEAT. UNFORTUNATELY...THIS RESPITE
WILL BE SHORT LIVED...AS A RAPID WARMING TREND WILL FOLLOW FOR THE
WEEKEND...WITH TEMPERATURES BACK WELL INTO THE MID 90S BY SUNDAY
AS RIDGING ONCE AGAIN ASSERTS DOMINANCE ACROSS THE AREA. NORTHWEST
FLOW ALOFT NEXT WEEK SUGGESTS ONE OR MORE CHANCES FOR
THUNDERSTORMS...BUT PROBABILITIES REMAIN LOW AND UNCERTAIN AT THE
MOMENT.
&&
.NEAR TERM /TODAY/...
ISSUED AT 1039 AM EDT FRI JUL 20 2012
ISOLATED SHOWERS AND SPRINKLES ARE TAKING THEIR TIME ABOUT GOING
AWAY. RUC ISNT IN ANY RUSH TO GET RID OF THEM. WILL UPDATE TO KEEP
SOME PRECIP THROUGH MOST OF AFTERNOON. CURRENT POPS STILL LOOK
GOOD...BUT WILL MENTION ISOLATED SPRINKLES WEST.
TAKING TEMPS DOWN A CAT IN THE EAST AND CENTRAL WITH PRECIP AND
CLOUDS HANGING ON LONGEST THERE.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
ISSUED AT 356 AM EDT FRI JUL 20 2012
WITH SURFACE HIGH PRESSURE THE DOMINANT FEATURE THROUGHOUT THE
SHORT TERM...TEMPERATURES ARE THE ONLY SIGNIFICANT FORECAST ISSUE.
MODEL 850 TEMPS WARM SIGNIFICANTLY AND QUICKLY THROUGH THE SHORT
TERM...AND ARE BACK INTO THE LOW 20C RANGE BY SUNDAY.
LATELY...THIS HAS TRANSLATED EASILY INTO THE MID 90S...AND WHILE
RECENT RAINFALL HAS MADE A SMALL DENT INTO EXTREME DROUGHT...IT
WILL TAKE MUCH MORE THAN WHAT HAS ALREADY OCCURRED TO MITIGATE
IMPACT OF DROUGHT ON TEMPERATURES. EXPECT WE WILL BEGIN TO EASILY
OUTPACE MOS ONCE AGAIN. GENERALLY RAISED CONSENSUS AT LEAST A
COUPLE OF DEGREES ON MAXES...WITH CORRESPONDING BUT SLIGHTLY
SMALLER HIKES DURING THE OVERNIGHTS.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
ISSUED AT 255 AM EDT FRI JUL 20 2012
LONG RANGE MODELS AND ENSEMBLES SUGGEST UPPER RIDGE ACROSS THE
PLAINS EARLY NEXT WEEK WILL SETTLE SOUTHEAST ACROSS THE SOUTHERN
STATES MIDWEEK WITH CENTRAL INDIANA ON THE SOUTHERN FRINGES OF THE
WESTERLIES. MODELS ALSO HAVE QPF THROUGH MUCH OF THE EXTENDED.
UPPER THICKNESS PATTERN IS CONDUCIVE TO PERIODIC NORTHWEST TO
SOUTHEAST MOVING THUNDERSTORM COMPLEXES ACROSS THE LOWER GREAT LAKES
AND OHIO VALLEY...SO WILL LEAVE AT LEAST SMALL CHANCE POPS
THROUGHOUT THE EXTENDED. KEPT AFTERNOON TEMPERATURES A FEW DEGREES
ABOVE MOS AND THE CENTRAL REGION INITIALIZATION AS WE STILL HAVE A
WAY TO GO BEFORE THE DROUGHT LOSES ITS IMPACT.
&&
.AVIATION /DISCUSSION FOR THE 201500Z KIND TAF UPDATE.../
ISSUED AT 1012 AM EDT FRI JUL 20 2012
SURFACE TROUGH HAS PASSED THROUGH KIND...WITH AN ASSOCIATED WIND
SHIFT TO 010-030 DEGREES. IFR CEILINGS...ALONG WITH A FEW AREAS OF
IFR VISIBILITY RESTRICTIONS IN LIGHT RAIN/DRIZZLE/LIGHT FOG EXIST
BEHIND THE WIND SHIFT. THESE CONDITIONS EXPECTED TO CONTINUE FROM
TIME TO TIME AT KIND INTO THE EARLY AFTERNOON HOURS...ROUGHLY
201700Z. DRIER AIR WORKING IN AT THE LOWER LEVELS COMBINED WITH WEAK
BOUNDARY LAYER HEATING...SHOULD ALLOW FOR CEILINGS TO RISE THROUGH
THE MVFR CATEGORY AND EVENTUALLY VFR LATER THIS AFTERNOON. WILL BUMP
BACK THE CEILING/VISIBILITY IMPROVEMENT BACK A COUPLE OF HOURS IN
THE UPDATE. PREVIOUS DISCUSSION FOLLOWS.
SATELLITE AND OBSERVATION TRENDS ALONG WITH MODELS SUGGEST MVFR AND
POSSIBLY IFR CONDITIONS EXPECTED THROUGH 19Z. AFTER THAT...CEILINGS
SHOULD COME UP TO VFR AND START BREAKING UP WITH CLEARING AFTER 00Z.
NORTHEAST WINDS 10 KNOTS OR SLIGHTLY MORE TODAY WILL BECOME LIGHT TO
CALM AFTER DARK. THIS COULD LEAD TO SOME MVFR OR WORSE FOG
OVERNIGHT. HOWEVER...A DRY DAY TODAY ALONG WITH DEW POINTS
DECREASING TO THE UPPER 50S AND LOWER 60S TONIGHT MAY KEEP IT P6SM.
WITH CONFIDENCE LOW...AND WITH IT THAT FAR OUT...WILL LEAVE FOG OUT
FOR NOW.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...NIELD
NEAR TERM...JK
SHORT TERM...NIELD
LONG TERM....MK
AVIATION...MK/JAS
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
641 AM CDT FRI JUL 20 2012
.UPDATE...FOR 12Z AVIATION DISCUSSION BELOW...
&&
.DISCUSSION.../ISSUED 414 AM CDT FRI JUL 20/
CURRENT H5 ANALYSIS SHOWS 597 DM H5 RIDGE NOW FIRMLY IN PLACE
ACROSS THE CENTRAL HIGH PLAINS...WITH 594 DM HEIGHTS ALL THE WAY
UP INTO CENTRAL SODAK. THERE IS A WEAK SHORTWAVE...REALLY SERIES
OF SHORT WAVES ROUNDING THE RIDGE ACROSS THE DAKOTAS THIS MORNING.
THIS HAS RESULTED IN THE DEVELOPMENT OF A WEAK LLJ AND MOIST
ISENTROPIC ASCENT ACROSS THE ERN DAKOTAS...WHERE SCT STORMS HAVE
BEEN SLOWLY INCREASING IN COVERAGE OVERNIGHT. AT THE SFC...A
RATHER WEAK AND DIFFUSE BOUNDARY STRETCHES FROM WINNIPEG DOWN
TOWARD BISMARK AND OFF INTO NW SODAK.
STILL LOOKS LIKE UPPER AIR PATTERN WILL NOT CHANGE A WHOLE LOT
THIS PERIOD...WITH UPPER RIDGE CONTINUING TO DOMINATE THE CENTER
OF THE COUNTRY FOR THE NEXT WEEK...WHILE OCCASIONAL SHORT WAVES
RIPPLE ACROSS SRN CANADA. MOST SUBSTANTIAL OF THESE WAVES HAS BEEN
SPINNING OFF THE BC COAST THE LAST FEW DAYS...WHICH THE GFS AND
ECMWF CONTINUE TO SEND ACROSS THE INTERNATIONAL BORDER MID WEEK.
IN FACT...LATEST CFS FORECAST WOULD INDICATE THERE WILL NOT BE
MUCH CHANGE TO THIS STATUS QUO OUT FOR THE NEXT 4 WEEKS. IF THIS
ENDS UP BEING THE CASE...THEN THE RECORD FOR WARMEST JULY ON
RECORD IN THE TWIN CITIES /1936/ MAY VERY WELL END UP BEING IN
JEOPARDY.
FOR TODAY...EXPECT CONVECTION JUST OFF TO OUR WEST TO SLOWLY WORK
EAST THIS MORNING...MOVING INTO WEST CENTRAL MN AROUND 12Z.
HOWEVER...DIURNAL WEAKENING OF THE LLJ SHOULD ALLOW FOR A FAIRLY
RAPID DECREASE IN STORM INTENSITY/COVERAGE...NOT TO MENTION THIS
ACTIVITY WILL BE MOVING INTO DRIER/LESS UNSTABLE AIR AS IT WORKS
EAST. MOST HI-RES MODELS ALONG WITH SREF PROBS HIGHLIGHT THIS IDEA
OF ACTIVITY WORKING INTO THE WRN CWA THIS MORNING...ONLY TO
QUICKLY DIE OFF ONCE IT GETS HERE. FOR THE AFTERNOON...EXPECT
ADDITIONAL ISO/SCT CONVECTION TO BE MAINLY NORTH OF THE MPX AREA
ALONG THE BOUNDARY...WITHIN A POOL OF 3000-3500 J/KG OF MLCAPE
INDICATED BY THE NAM FROM NE SODAK THROUGH THE FARGO AREA AND UP
TOWARD INL. GOING THROUGH THE NIGHT...ANY OF THIS ACTIVITY WILL
BEGIN TO SLOWLY SAG SOUTH INTO THE AREA AS BOTH THE BOUNDARY AND
LLJ /AS WEAK AS IT IS/ WORK INTO CENTRAL MN. WITH THE LLJ SLOWLY
PUSHING SOUTH THROUGH THE MPX AREA OVERNIGHT...WOULD SUSPECT AT
LEAST SOME CONVECTION TO DEVELOP AS WE HAVE SEEN ACROSS THE
DAKOTAS THIS EVENING WITH IN THE LLJ. HOWEVER...INSTABILITY FRI
NIGHT WILL BE MUCH WEAKER THAN WHAT IS CURRENTLY BEING SEEN OVER
THE DAKOTAS...SO COVERAGE SHOULD NOT BE AS GREAT. GIVEN PROXIMITY
TO THE UPPER RIDGE...SHEAR WILL CONTINUE TO BE WEAK...SO NOT
ANTICIPATING ANY WIDESPREAD SVR THREAT UNLESS CONVECTION CAN GET
ORGANIZED INTO A SEMI-LINEAR SYSTEM AT SOME POINT. GOING INTO
SATURDAY...FOCUS FOR VERY SMALL THUNDER CHANCES WILL PUSH INTO THE
SRN PART OF THE CWA AS THE WEAK BOUNDARY PUSHES INTO IA.
FOR HIGHS THIS AFTERNOON...SHOULD SEE A NICE GRADIENT IN VALUES
FROM WEST TO EAST ACROSS THE AREA. NAM/ECMWF SHOWS 925-850 MB LAYER
TEMPS INCREASING TO AROUND 30C THIS AFTERNOON IN WEST CENTRAL MN.
VALUES THIS HIGH YESTERDAY YIELDED HIGHS WELL INTO THE 100S ACROSS
THE DAKOTAS...SO BUMPED UP HIGHS A FEW DEGREES IN FAR WRN SECTIONS
OF THE CWA. ASSUMING UPPER CLOUDS DO NOT SPOIL THE PARTY...FULLY
EXPECT PLACES OUT AROUND MADISON TO MAKE A RUN AT 100 TODAY. OVER
WRN WI...TEMPS IN THE 925-850 LAYER WILL BE DOWN CLOSE TO
22C...AND MIXING THESE DOWN TO THE SFC YIELDS HIGHS ONLY IN THE
MID 80S. GOING INTO SATURDAY...NAM/ECMWF SHOW THE WARM AIR PUSHING
SOUTH OF HERE AND LOOKS LIKE MOST OF THE AREA WILL SEE A BREAK
FROM HIGHS IN THE 90S ON SATURDAY...BEFORE THEY COME BACK SUNDAY.
FOR SUNDAY THROUGH MONDAY NIGHT...THE MPX AREA STILL LOOKS TO BE
PERCHED ON THE N/NE EDGE OF THE UPPER RIDGE AND ASSOCIATED
CAP...BUT FORCING FOR ANY CONVECTION BASED ON H85 LLJ/MOISTURE
TRANSPORT FORECASTS LOOKS TENUOUS AT BEST AND WOULD SUSPECT THIS
PERIOD TO BE PRETTY MUCH DRY. IN ADDITION TO THE DRY WX...HIGHS
SHOULD HAVE NO PROBLEM FINDING THEIR WAY BACK INTO THE 90S FOR ALL
BUT THE NRN FRINGE OF THE MPX CWA.
TUESDAY THROUGH THURSDAY PERIOD WILL SEE A WEAKENING/FLATTENING
OUT OF THE UPPER RIDGE AS A STRONG SHORT WAVE MOVES ACROSS SRN
CANADA. WITH THE 20.00 RUNS...THE GFS/ECMWF ARE SHOWING A BIT MORE
DISAGREEMENT WITH THIS SYSTEM...WITH THE ECMWF RUNNING ABOUT 12-18
HOURS FASTER THAN THE GFS. BIGGEST IMPACT WITH THIS IS THAT AN
ECMWF SOLUTION WOULD BRING AN END TO THE PRECIP THURSDAY...WHILE
THE GFS KEEPS THE FRONT AND ASSOCIATED PRECIP AROUND INTO FRIDAY.
BEST CHANCE FOR PRECIP IN THIS PERIOD STILL LOOKS TO BE TUESDAY
AFTERNOON INTO TUESDAY NIGHT AS A WARM FRONT SHARPENS ACROSS THE
MPX AREA AND SLOWLY LIFTS NORTHEAST. ABOUT THE ONLY THING THAT
WOULD KEEP HIGHS OUT OF THE 90S DURING THIS DAYS IS EXTENSIVE
CLOUD COVER/PRECIP NORTH OF THE BOUNDARY TUESDAY...BUT SHOULD BE A
GOOD OPPORTUNITY TO CONTINUE PILING UP THE 90 DEGREE HIGHS ACROSS
MUCH OF THE AREA. THE ECMWF DOES NOT INDICATE THE POTENTIAL FOR
90 DEGREE HIGHS LEAVING THE AREA UNTIL THE END OF THE WEEK...AND
EVEN THEN IT ONLY PUSHES THEM OVER TO IA AND SODAK.
&&
.AVIATION.../12Z TAF ISSUANCE/
SHOWER AND THUNDERSTORM CHANCES ARE THE MAIN FORECAST CONCERN
THIS TAF PERIOD. THE 20.08 HRRR CONTINUED TO DEPICT THE
ADVANCEMENT OF SHRA/TS ACTIVITY OVER EASTERN SD ACROSS THE TAF
AREA TODAY. HOWEVER...ITS INITIALIZATION WAS RELATIVELY POOR...SO
OPTED NOT TO INCLUDE MID-DAY SHRA/TS AT KMSP/KRNH/KEAU AS THE
SOLUTION WOULD SUGGEST. DID HOWEVER INCLUDE A MENTION OF SHRA/TS
AT KAXN/KSTC/KRWF TODAY...AS THE SHORTWAVE OVER ERN SD IS
DETECTABLE IN MORNING RADAR IMAGERY. H85-H7 THETA E ADVECTION
WANES NOTABLY THIS MORNING HOWEVER...SO ANTICIPATE GRADUAL
DECAYING OF THE CURRENT ACTIVITY...AND VICINITY VERBAGE SHOULD BE
SUFFICIENT FOR THE MOST PART. TONIGHT WILL BRING ANOTHER
OPPORTUNITY FOR CONVECTIVE DEVELOPMENT AS THE LLJ RAMPS UP AGAIN.
HAVE INCLUDED PROB30 GROUPS FOR KMSP/KEAU/KRNH AFTER 05Z SAT.
SOUTHERLY WINDS INCREASING TODAY...WITH SUSTAINED SPEEDS AROUND 10
KNOTS AND GUSTS INTO THE MID/UPPER TEENS /KNOTS/.
KMSP...VFR EXPECTED TODAY. WHILE AN ISOLATED SHOWER OR
THUNDERSTORM CANNOT BE RULED OUT TODAY...CONFIDENCE AND
PROBABILITY ARE TOO LOW TO INCLUDE IT IN THE TAF DURING THE
DAYTIME. TONIGHT WILL BRING A SLIGHTLY HIGHER CHANCE AS THE LLJ
INCREASES...SO HAVE INCLUDED A PROB30 AFTER 05Z SAT. SOUTHERLY
WINDS WILL PREVAIL THROUGH TONIGHT...WITH A SHIFT TO SOUTHWESTERLY
OCCURRING AROUND/AFTER 12Z SAT.
/OUTLOOK/
SATURDAY...VFR WITH A 20 PERCENT CHANCE OF TSRA. WINDS N AT 10-15KTS.
SUNDAY...VFR WITH A 20 PERCENT CHANCE OF TSRA. WINDS S AT 5-10KTS.
MONDAY...VFR. WINDS NW AT 5-10KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
LRS/MPG
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1005 AM EDT FRI JUL 20 2012
.SYNOPSIS...
A COLD FRONT WILL APPROACH FROM THE NORTH TODAY AS AN UPPER LEVEL
DISTURBANCE PROGRESSES SOUTHEAST FROM THE OHIO VALLEY INTO THE
CAROLINAS. SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ARE
EXPECTED THIS AFTERNOON THROUGH THE WEEKEND AS THE FRONT STALLS OUT
OVER THE REGION.
&&
.NEAR TERM /TODAY AND TONIGHT/...
AS OF 1005 AM FRIDAY...
THE LATEST SURFACE ANALYSIS SHOWED A WAVY FRONTAL BOUNDARY...WITH
SURFACE WAVES ALONG THE BOUNDARY...EXTENDING MAINLY ALONG AND NEAR
THE OHIO RIVER...THEN SOUTHEAST FROM SOUTHERN OHIO TOWARD DELMARVA.
A SURFACE TROUGH WAS ALSO LOCATED OVER THE FOOTHILLS AND FAR WESTERN
PIEDMONT. WHILE THE SURFACE GRADIENT WAS SLACK OVER CENTRAL NORTH
CAROLINA...AMDAR SOUNDINGS AS WELL AS THE KGSO 12Z SOUNDING SHOWED
SOME WINDS NEAR THE INVERSION AROUND 20KT. ALREADY...THERE HAVE BEEN
A COUPLE OF GUSTS APPROACHING 20KT ON SURFACE OBSERVATIONS...NOTABLY
AT KFAY.
WHILE DIFFICULT TO RESOLVE ON STANDARD WATER VAPOR IMAGERY...EARLY
MORNING VISIBLE IMAGERY WOULD SUGGEST AN MCV MOVING OVER FAR
NORTHEAST TENNESSEE...WHICH ESSENTIALLY ALL OF THE SHORT-TERM
GUIDANCE FORECASTS MOVING EAST OVER OR VERY NEAR CENTRAL NORTH
CAROLINA DURING THE AFTERNOON. THE RUC IS THE STRONGEST AMONG THE
GFS AND NAM...AND WHILE PRECIPITABLE WATER VALUES ARE CURRENTLY AT A
REGIONAL MINIMUM OVER THE WESTERN THIRD OF THE STATE ON THE LATEST
SPC MESOANALYSIS...WITH THE APPROACH OF THE MCV AND EXPECTED SLOW
EASTWARD PROGRESS OF THE SURFACE TROUGH IN RESPONSE...850MB THETA-E
ADVECTION FROM THE SOUTHWEST SHOULD LIMIT OR NULLIFY ANY
PRECIPITABLE WATER REDUCTION THIS AFTERNOON. 850MB DEW POINTS ARE IN
THE TEENS ON THE LATEST UPPER-AIR ANALYSIS AT THAT LEVEL.
MORNING LOW CLOUDS WERE GRADUALLY DIMINISHING ON THE LATEST VISIBLE
IMAGES...AND WHILE 1000-500MB LAPSE RATES ARE NOT FORECAST
PARTICULARLY HIGH THIS AFTERNOON...TO AROUND 6.5C/KM...AND DCAPE IS
FAIRLY LOW...AROUND 200J/KG...THE COMBINATION OF BETTER SYNOPTIC
FORCING...BETTER AVAILABLE LOW-LEVEL WINDS...AND SOME INCREASING
SHEAR LATE ESPECIALLY NORTHWEST...WHERE 0-6KM SHEAR SHOULD INCREASE
TO AROUND 25KT...SHOULD PROVIDE FOR THE POTENTIAL OF SOME
THUNDERSTORMS ORGANIZING ENOUGH TO HAVE A RISK FOR SEVERE WEATHER
WITH DAMAGING WIND THE PRIMARY SEVERE WEATHER THREAT. SREF
PROBABILISTIC FORECAST FOR GREATER THAN 100 CLOUD-TO-GROUND
LIGHTNING STRIKES SUGGESTS A MAXIMUM OVER THE WESTERN PIEDMONT...AND
THIS SEEMS REASONABLE WHERE THE -10C TO -30C CAPE IS A MAXIMUM...TO
AROUND 600J/KG. THE PREVIOUS FORECAST OF SCATTERED TO NUMEROUS
SHOWERS AND THUNDERSTORMS DEVELOPING SEEMS VERY REASONABLE AND
CONTINUED THIS FOR THE AFTERNOON...INCREASING THE RAW NUMBERS ON THE
CHANCES FOR RAIN MAINLY TOWARD THE YADKIN RIVER TO JUST SHY OF
CATEGORICAL BASED ON THE CONSENSUS OF THE ABOVE...PLUS MOS GUIDANCE
AND THE LATEST HRRR WRF OUTPUT. TEMPERATURES IN MOST LOCATIONS...
AFTER A SLOW START IN THEIR RISE DUE TO CLOUDS...SHOULD REACH LOWER
TO MID 90S...POSSIBLY MORE OF A STRUGGLE TO REACH 90 IN THE
IMMEDIATE TRIAD. -DJF
TONIGHT...SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS WILL
EVENTUALLY DECREASE FROM W-E OR NW-SE AFTER MIDNIGHT IN ASSOC/W
CONVECTIVE OVERTURNING AND NOCTURNAL STABILIZATION. HOWEVER...WILL
KEEP AT LEAST 20-30% PRECIP CHANCES IN PLACE THE REMAINDER OF THE
NIGHT GIVEN AN APPROACHING UPPER LEVEL TROUGH IN THE PRESENCE OF A
VERY MOIST AND MARGINALLY UNSTABLE AIRMASS. LOW-LEVEL SHEAR BETWEEN
SUNSET AND MIDNIGHT (01-04Z) THIS EVENING (EAST OF HWY 1) IS PROGGED
TO BE SIMILAR TO THAT ANALYZED BY SPC MESOANALYSIS AT 09Z THIS
MORNING (150 M2/S2 OF 0-1 KM HELICITY AND 20-25 KT OF 0-1 KM BULK
SHEAR OVER CENTRAL/EASTERN NC). HOWEVER...DEEP CONVECTION WOULD HAVE
A DIFFICULT TIME REMAINING SFC-BASED BY THE TIME LOW-LEVEL SHEAR
STRENGTHENS IN CENTRAL NC...AND THE PROBABILITY OF A BRIEF/ISOLD TOR
IS TOO LOW TO MENTION. IF THERE WAS A VERY LOW-END POTENTIAL...IT
WOULD LIKELY BE EAST OF I-95 BETWEEN 01-04Z IN AREAS NOT STABILIZED
BY OUTFLOW AND/OR THE SEABREEZE. WITH A VERY MOIST LOW-LEVEL AIRMASS
IN PLACE...EXPECT LOWS TONIGHT IN THE LOWER 70S...OR 71-74F. -VINCENT
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 145 AM FRIDAY...
PULSE THUNDERSTORMS WILL BRING LOCALLY VERY HEAVY RAIN AND GUSTY
WINDS BOTH SATURDAY AND SUNDAY.
A WEAK SURFACE COLD FRONT IS EXPECTED TO DRIFT SOUTHERLY SOUTH
THROUGH TN/WVA/VA SATURDAY... POSSIBLY REACHING NORTHERN NC LATE
SATURDAY AND SATURDAY NIGHT... BEFORE STALLING OVER OUR REGION INTO
SUNDAY. THE STRONG CONFLUENCE ALONG THIS FRONT WILL COMBINE WITH
STRONG SURFACE HEATING TO PROVIDE MORE THAN ADEQUATE LIFT OF VERY
MOIST AIR IN SUPPORT OF THE DEVELOPMENT OF NUMEROUS THUNDERSTORMS
AGAIN SATURDAY AFTERNOON INTO THE EVENING. AREAL AVERAGE QPF SHOULD
BE ON THE ORDER OF 0.50 TO 1 INCH... WITH SOME LOCALLY VERY HEAVY
AMOUNTS IN EXCESS OF 2 INCHES POSSIBLE DUE TO THE MOISTURE POOLING
AND SLOW STORM MOVEMENT. THIS INFORMATION WILL CONTINUE TO BE
MENTIONED IN THE HAZARDOUS WEATHER OUTLOOK (HWO). SUNDAY SHOULD
AGAIN BE JUST AS CONVECTIVELY ACTIVE WITH THE LOW LEVEL CONFLUENCE
ZONE BECOMING NEARLY STATIONARY OVER THE PIEDMONT. QPF SUNDAY WILL
AGAIN INDICATE 0.50 TO 1 INCH AREAL AVERAGES... WITH LOCALLY 2
INCHES AGAIN POSSIBLE. HOPEFULLY... THE HEAVIER AMOUNTS WILL FALL IN
DIFFERENT LOCATIONS THAN THOSE THAT RECEIVE HEAVY AMOUNTS BOTH
FRIDAY AND SATURDAY. THAT IS NOT ALWAYS THE CASE HOWEVER...
THEREFORE SOME LOCAL AREAS MAY RECEIVE OVER 4 INCHES OF RAIN TOTAL
TODAY THROUGH SUNDAY.
SHEAR IS FORECAST TO CONTINUE TO BE LACKING WHICH OFTEN WILL LEAD TO
THE CONVECTIVE MODE BEING "PULSE"... OR TYPICAL SUMMERTIME STRONG
THUNDERSTORMS. THIS MEANS LESS IN THE WAY OF ORGANIZED SEVERE
STORMS. HOWEVER... EVEN THOUGH "ORGANIZED AND WIDESPREAD" SEVERE
THUNDERSTORMS ARE NOT FORECAST... THERE WILL LIKELY BE BE A RAPID
DEVELOPMENT OF "PULSE" THUNDERSTORMS BOTH SATURDAY AND SUNDAY. SOME
OF THESE MAY BECOME LOCALLY SEVERE WITH DAMAGING WIND GUSTS TO 60
MPH POSSIBLE. WE WILL HIGHLIGHT THIS LOCAL PULSE SEVERE CHANCE AS
WELL IN THE HWO FOR BOTH DAYS. HIGHS SATURDAY ARE FAVORED TO BE IN
THE 86-92 RANGE... N TO S. LOWS SATURDAY NIGHT... 69-73. HIGHS
SUNDAY MAY BE A BIT COOLER (ONLY DUE TO THE FORECAST HIGH DEW POINTS
AND WETTER GROUND BY THEN) 85-90.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 145 AM FRIDAY...
ANOTHER HOT AND HUMID WEEK...WITH A CHANCE OF MAINLY AFTERNOON AND
EVENING THUNDERSTORMS.
STRONG UPPER RIDGING IS FORECAST TO BEGIN TO EXTEND EASTWARD FROM
THE CENTRAL UNITED STATES TO NEAR THE APPALACHIANS BY MID WEEK. THE
BOUNDARY THAT IS FORECAST TO BRING THE THUNDERSTORMS TO OUR REGION
THIS WEEKEND IS FORECAST TO DISSIPATE OVER OUR AREA MONDAY THROUGH
TUESDAY. AS WE LOSE THE INFLUENCE OF THE BOUNDARY (LIFT/MOISTURE
POOLING/CONVERGENCE) WE WILL SEE THE WIDESPREAD STORMS OF THE
WEEKEND BECOME SCATTERED DURING MONDAY AND TUESDAY. A NW FLOW ALOFT
MAY NOT TURN OUT TO BE THAT MUCH DRIER MID TO LATE WEEK AS
DISTURBANCES ALOFT MAY TRIGGER AT LEAST SCATTERED DIURNAL STORMS ALL
WEEK. WE WILL MAINTAIN POPS OF AT LEAST CLIMATOLOGY FOR LATE JULY
(35 PERCENT OR SO) MOST OF THE WEEK.
THE HEAT WILL ALSO BEGIN TO RETURN WITH LESS IN THE WAY OF CLOUDS/
STORMS DURING THE PM HOURS. THEREFORE...HIGHS ARE EXPECTED TO BE IN
THE UPPER 80S TO LOWER 90S MONDAY...90-95 TUESDAY... THEN MOSTLY MID
90S BY THURSDAY. IT WILL CONTINUE VERY MUGGY WITH DEW POINTS IN THE
70S. LOWS WILL ALSO BE IN THE 70S.
&&
.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
AS OF 1005 AM FRIDAY...
MVFR CEILINGS WILL LIFT AND BECOME VFR DURING THE MORNING...WITH
MOSTLY VFR CONDITIONS EXPECTED THEREAFTER THROUGH 12Z. SURFACE WINDS
WILL SHOW SOME GUSTINESS...POSSIBLY TO NEAR 20KT PARTICULARLY TOWARD
KFAY AND KRWI THIS AFTERNOON. NUMEROUS SHOWERS AND THUNDERSTORMS ARE
EXPECTED TO DEVELOP OVER CENTRAL NC THIS AFTERNOON AND LINGER INTO
THIS EVENING AS A COLD FRONT APPROACHES THE AREA FROM THE NORTH.
WILL MENTION VCSH AT ALL TAF SITES BY 17-18Z...WITH A TEMPO GROUP
FOR IFR CONDITIONS AND GUSTY WINDS BETWEEN 18-22Z AT INT/GSO AND
19-23Z AT RDU/RWI/FAY...WHEN DEEP CONVECTION WILL BE MOST LIKELY.
ISOLD TO SCATTERED SHOWERS AND STORMS WILL REMAIN POSSIBLE THROUGH
THE END OF THE TAF PERIOD...THOUGH CONVECTION SHOULD WEAKEN AND
DECREASE IN COVERAGE AFTER 03Z THIS EVENING.
LOOKING AHEAD:
EXPECT SCATTERED TO NUMEROUS SHOWERS AND STORMS DURING THE AFTERNOON
AND EVENING HOURS SATURDAY AND SUNDAY AS THE FRONT STALLS OUT OVER
VA/NC. SUB-VFR FOG AND/OR CEILINGS WILL BE POSSIBLE DURING THE
PRE-DAWN HOURS EACH MORNING IN ASSOCIATION WITH A MOIST AIRMASS IN
PLACE. AFTERNOON AND EVENING SHOWERS/STORMS AND PRE-DAWN FOG/STRATUS
WILL REMAIN POSSIBLE THROUGH EARLY/MID NEXT WEEK IN ASSOCIATION WITH
A SEASONABLY MOIST AIRMASS IN THE PRESENCE OF NW FLOW ALOFT. -VINCENT
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...DJF/VINCENT
SHORT TERM...BADGETT
LONG TERM...BADGETT
AVIATION...DJF/VINCENT
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1037 AM EDT FRI JUL 20 2012
.SYNOPSIS...
A COLD FRONT WILL APPROACH FROM THE NORTHWEST TODAY AND ARRIVE ON
SATURDAY. THE FRONT IS EXPECTED TO STALL OVER THE AREA THROUGH THE
WEEKEND BEFORE DISSIPATING MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AT 1030 AM EDT... MORNING DATA CONTINUE TO INDICATE POTENTIAL FOR
THUNDERSTORMS DURING THE AFTERNOON AND EVENING... BUT CLOUDINESS
FROM OVERNIGHT MCS TO OUR WEST AND FRONT TO THE NORTH IS SPREADING
OVER MUCH OF THE CWA. CLOUDS COULD PUT A LITTLE BIT OF A DAMPER OR
DELAY ON CONVECTIVE INITIATION... BUT THERE WILL BE PLENTY OF
OPPORTUNITY FOR CLOUDS TO ERODE THUS ALLOWING BOUNDARY LAYER TO
COLLECT SOME WARMTH. IN THE VERY NEAR TERM... WILL DECREASE POPS
BUT INCREASE THEM TO CURRENT FORECAST VALUE BY MID TO LATE AFTERNOON.
AFTERNOON RAP CAPES ARE IN THE 1500 TO 3000 J/KG RANGE WITH AXIS OF
HIGHEST CAPE FROM APPROXIMALY KAND TO KCLT BY 17Z. NAM CAPES ARE A
LITTLE LOWER... GENERALLY 1000 TO 2000 J/KG... EXCEPT LESS THAN 1000
OVER MOUNTAINS. WIND PROFILES IDENTIFY VERY LITTLE SHEAR... SO PULSE
STORMS WITH LITTLE ORGANIZATION EXPECTED. QUITE POSSIBLE THAT SOME
MULTICELL CLUSTERS CAN DEVELOP... BUT RAP DCAPES ARE ONLY AROUND 500
J/KG SO THAT LOWERS CONFIDENCE A LITTLE THAT MAJOR COLD POOLS WILL
DEVELOP. HOWEVER... NAM MOVES AN AXIS OF DCAPE AROUND 1000 J/KG
ACROSS CWA FROM WEST TO EAST LATER TODAY. POTENTIAL FOR THAT FEATURE
WILL NEED TO BE MONITORED.
PREVIOUS DISCUSSION...
AS OF 605 AM EDT...MCS ACTIVITY HAS BEEN WEAKENING TO OUR WEST...BUT
IT IS STILL GENERATING QUITE A FEW CLOUD TO GROUND LIGHTNING STRIKES
OVER CENTRAL TENN AND NORTHERN ALABAMA. OVER THE PAST FEW
HOURS...THE ONLY SHOWER ACTIVITY WE HAVE SEEN HAS BEEN OVER THE FAR
WESTERN NC MTS...HOWEVER COVERAGE SHOULD BEGIN TO INCREASE LATER
THIS MORNING AS THINGS BEGIN TO HEAT UP AND THE FIRST UPPER
SHORTWAVE APPROACHES. TEMPS ARE HOLDING A BIT WARMER THAN
ANTICIPATED...SO I BUMPED UP THE MIN TEMPS A DEGREE OR 2.
PREVIOUS DISCUSSION...
A COLD FRONT WILL APPROACH FROM THE NORTH LATER TODAY...WHILE A PAIR
OF FAIRLY POTENT LOOKING H5 SHORTWAVES MOVE INTO THE BASE OF THE
TROUGH. WITH THE ATMOSPHERE REMAINING MOIST AND UNSTABLE...I KEEP
POPS AT LIKELY OVER MOST OF THE CWFA DURING THE LATE AFTERNOON AND
THRU THE LATE EVENING HOURS. CONDITIONS WILL BE SUFFICIENT FOR
SEVERE THUNDERSTORMS AGAIN...AND WITH UNIDIRECTIONAL SHEAR
PRESENT...SOME ORGANIZATION IS POSSIBLE...ESPECIALLY IN THE
PIEDMONT. WITH BETTER STEERING FLOW AND MOVING STORMS...FLOODING
SHOULD NOT BE AS MUCH OF A CONCERN...HOWEVER LOCALIZED...HIGH QPF
WILL BE POSSIBLE FROM TRAINING OR REPEATING CELLS. MAXIMUM
TEMPERATURES WILL BE NEAR NORMAL...AS LONG AS CLOUD COVER BREAKS
ENOUGH TO ALLOW SUFFICIENT HEATING.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 310 AM FRIDAY...AN UPPER TROF WITH A SERIES OF EMBEDDED
SHORTWAVES REMAINS OVER THE REGION SAT AS THE SFC BOUNDARY STALLS
ACROSS THE AREA. THIS COMBINED WITH RIGHT ENTRANCE REGION OF THE
UPPER JET OVER THE CWA WILL PROVIDE ENOUGH SYNOPTIC SCALE FORCING
AND UPPER DIVERGENCE FOR LIKELY CONVECTION SAT...WITH SCT CONVECTION
LINGERING THRU THE EVE. DUE TO LOWER HEIGHTS...INCREASED CLOUDS AND
SHWRS...HIGH TEMPS WILL BE BELOW AVG SAT WITH LOWS AROUND AVG SAT
NIGHT. THE SHORT WAVE MOVES E OF THE REGION SUN BUT A WEAKNESS
BETWEEN A RIDGE TO THE W AND ONE TO THE E WILL LEAVE A SHEAR AXIS
OVER THE AREA. IT STILL APPEARS THE FRONT WILL BEGIN TO WASH OUT BUT
A WEAK BOUNDARY IS EXPECTED TO LINGER ACROSS THE AREA. THIS SHOULD
BE ENOUGH FOCUS FOR AT LEAST SCT CONVECTION SUN AFTN-EVE. LOOK FOR
TEMPS WITHIN A DEG OR SO OF AVG.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 310 AM FRIDAY...A WEAK TROF WILL REMAIN OVER THE REGION
MON...THEN THE AXIS WILL TRANSITION E THRU THE WEEK. AS AN UPPER
RIDGE BEGINS TO BUILD IN FROM THE W TUE-WED...A SERIES OF WEAK SHORT
WAVES WILL MOVE OVER THE AREA. A LEE TROF IS EXPECTED TO REMAIN
ACROSS THE PIEDMONT WITH ABOVE AVG LOW LEVEL MOISTURE LINGERING OVER
THE AREA...LEADING TO DIURNALLY ENHANCED CONVECTION EACH DAY. EXPECT
NEAR TO SLIGHTLY ABOVE AVG TEMPS MON...ABOVE AVG TUE-THU.
&&
.AVIATION /15Z FRIDAY THROUGH TUESDAY/...
AT KCLT... BOUNDARY LAYER HEATING AND MIXING GRADUALLY ELIMINATING
STRATUS CEILING NEAR 15 HND FT BUT COULD LINGER VICINITY TERMINAL
UNTIL APPROXIMATELY 16Z. SURFACE WIND WILL BE SOUTHWEST 10 KT OR LESS.
LAYERS OF MID AND HIGH CLOUDS FROM REMNANTS OF CONVECTION TO THE
WEST AND FRONT TO THE NORTH WILL CONTINUE TO DRIFT OVER THE AREA.
CONVECTIVE CLOUDS WITH BASES AROUND 5K FT WILL BE THE PREDOMINANT
LOWER CLOUD DURING THE AFTERNOON AND INTO THE EVENING. AFTER 18Z...
CEILING AND VISIBILITY RESTRICTIONS WILL EXIST IN THUNDERSTORMS...
POSSIBLY ACCOMPANIED BY SMALL HAIL AND STRONG AND GUSTY WIND
VARIABLE IN DIRECTION. LOW STRATUS AND FOG COULD OCCUR VICINITY
AIRFIELD SATURDAY MORNING.
REMAINDER TAF SITES... MID AND HIGH CLOUD LAYERS PRODUCED BY
CONVECTIVE STORMS TO THE WEST AND APPROACHING WEAK COLD FRONT WILL
DRIFT ACROSS AREA. DURING AFTERNOON PREDOMINANT LOW CLOUD WILL BE
BASES OF CONVECTIVE CLOUDS AT 4-5K FT. CEILING AND VISIBILITY
RESTRICTIONS WILL EXIST IN THUNDERSTORMS... POSSIBLY ACCOMPANIED BY
SMALL HAIL AND STRONG AND GUSTY WIND. THUNDERSTORMS LIKELY TO
CONTINUE INTO THE NIGHT. LOW AND STRATUS AND FOG CLOUD OCCUR
SATURDAY MORNING... PARTICULARLY AT SITES THAT HAVE RAINFALL.
OUTLOOK...AS A COLD FRONT STALLS OVER THE AREA...SCATTERED TO
NUMEROUS (MAINLY DIURNAL) CONVECTION AND ASSOCIATED RESTRICTIONS
WILL PERSIST THROUGH THE WEEKEND. LATE NIGHT/MORNING FOG AND LOW
STRATUS PROBABILITIES WILL ALSO REMAIN FAIRLY HIGH...ESPECIALLY IN
THE MTN VALLEYS.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...JAT
NEAR TERM...LGL
SHORT TERM...RB
LONG TERM...RB
AVIATION...JPT
AREA FORECAST DISCUSSION...UPDATED
NWS MEMPHIS TN
1100 AM CDT FRI JUL 20 2012
.UPDATE...
CONDITIONS AT 11 AM HAVE WARMED INTO THE 90S WEST OF A LINE FROM
ROUGHLY DYERSBURG TO CLARKSDALE. FURTHER EAST...SOME INFLUENCE
FROM THE ROBUST THUNDERSTORM ACTIVITY IN MIDDLE TENNESSEE /CLOUDS
AND OUTFLOWS/ HAS TEMPERED TEMPERATURES A BIT IN THE 80S. THE
925MB THERMAL RIDGE HAS NOW CENTERED ITSELF ALONG A LINE FROM
OKLAHOMA CITY EAST TO MEMPHIS. AN ILL-DEFINED FRONT APPEARS TO BE
SITUATED OVER NRN MS WITH A FEW STORMS AHEAD OF IT OVER MONROE
COUNTY.
WILL LEAVE THE CURRENT HEADLINE CONFIGURATION IN PLACE...BUT THE
EASTERN COUNTIES WITHIN THE WARNING ARE MARGINAL GIVEN THE CURRENT
CLOUD COVER. NAM 925 MB TEMPS HAVE ALSO COME DOWN A COUPLE
DEGREES...SO REDUCED HIGHS BY A DEGREE OR TWO IN MOST PLACES.
STILL THINK HEAT INDICES OF 110F ARE OBTAINABLE OVER THE DELTA AND
NEAR I-40 IN SWRN TN.
MODELS ARE RELUCTANT TO DEVELOP ANYTHING SIGNIFICANT THIS
AFTERNOON...BUT THE HRRR DOES SHOW ISOLATED CELLS DEVELOPING LATE
THIS AFTERNOON OVER MOST OF THE AREA SO DID NOT FEEL I COULD
REMOVE POPS.
BORGHOFF
&&
.PREV DISCUSSION... /ISSUED 508 AM CDT FRI JUL 20 2012/
DISCUSSION...
TEMPERATURES ARE GENERALLY RUNNING 1-5 DEGREES WARMER THAN THEY
WERE 24 HOURS AGO...AND DEW POINTS ARE AROUND 2 DEGREES WARMER
WITH THE EXCEPTION OF NORTHEAST ARKANSAS WHERE SOME DRIER AIR IS
WORKING IN. 4 AM TEMPERATURES REMAIN IN THE LOW 80S AT MANY
LOCATIONS ACROSS THE MIDSOUTH THE WARMEST READINGS ARE IN THE
DELTA AREAS...INCLUDING THE MEMPHIS METRO AREA WITH THE COOLEST
READINGS IN NORTHEAST MISSISSIPPI AND WEST TENNESSEE NEAR THE
TENNESSEE RIVER. A FEW SHOWERS DEVELOPED ALONG THE
TENNESSEE/MISSISSIPPI STATE LINE EARLIER THIS MORNING...BUT HAVE
NOW PRETTY MUCH DISSIPATED. MID AND HIGH CLOUDS OVERSPREAD MOST OF
THE MIDSOUTH HELPING TO LIMIT RADIATIONAL COOLING.
WE SHOULD SEE ANOTHER VERY HOT DAY TODAY DESPITE SOME CLOUD
COVER.AN EXCESSIVE HEAT WARNING HAS BEEN ISSUED FOR MUCH OF THE
AREA. TEMPERATURES WILL START A FEW DEGREES WARMER THAN YESTERDAY
AND WARM QUICKLY INTO THE 90S. CONVECTION WILL GET GOING FAIRLY
EARLY AND MAY PROVIDE SOME LOCALIZED RELIEF TO THE HEAT...BUT DO
NOT THINK COVERAGE...OR THE DURATION OF ANY PRECIPITATION WILL
LIMIT THE HEATING ON ANY LARGE SCALE. THE EXCEPTION MAY BE ACROSS
PORTIONS OF NORTHEAST MISSISSIPPI AND WEST TENNESSEE NEAR THE
TENNESSEE RIVER WHERE STORMS ARE EXPECTED TO BE MOST WIDESPREAD.
AFTERNOON HIGHS WILL BE AT OR ABOVE 99 DEGREES ACROSS MOST OF THE
AREA...WITH THE EXCEPTION BEING THE SAME AREA MENTIONED ABOVE. THE
WARMEST READINGS WILL LIKELY BE ACROSS THE DELTA AND NORTHEAST
ARKANSAS WHERE TEMPERATURES MAY APPROACH 105 DEGREES. HEAT INDICES
MAY CLIMB AS HIGH AS 114 DEGREES.
ALTHOUGH HEAT WILL BE THE MAIN STORY TODAY...THE STORM PREDICTION
CENTER ALSO HAS MUCH OF THE MIDSOUTH IN A SLIGHT RISK FOR SEVERE
THUNDERSTORMS. THE INTENSE HEAT AND HIGH HUMIDITY WILL RESULT IN A
VERY UNSTABLE AIRMASS FEATURING CAPE VALUES IN EXCESS OF 3500 J/KG
AND LI`S LOWER THAN -8C. THE MOST UNSTABLE CONDITIONS WILL BE
FOUND IN NORTH MISSISSIPPI AND WEST TENNESSEE. DAMAGING WIND WOULD
BE THE PRIMARY THREAT FROM THESE STORMS. OUTFLOW FROM THE ONGOING
CONVECTION IN CENTRAL TENNESSEE MAY BECOME A FOCUS FOR REDEVELOPMENT
OF STORMS DURING THE DAY TODAY. HAVE NOT SEEN ANY INDICATION THAT
IT HAS PROPAGATED VERY FAR WEST YET...BUT IT COULD LEAD TO BETTER
RAIN CHANCES FARTHER WEST DEPENDING ON ITS EVOLUTION/MOVEMENT.
A WEAK COLD FRONT WILL SINK SOUTH OF THE AREA TONIGHT ALLOWING A
COOLER DRIER AIRMASS TO FILTER INTO THE AREA. AS A RESULT...WE
PROBABLY WILL NOT NEED ANY ADDITIONAL HEAT PRODUCTS TOMORROW.
HIGHS SHOULD BE IN THE MIDDLE 90S AT MOST LOCATIONS. GUIDANCE
DIFFERS SIGNIFICANTLY WITH HIGHS OVER THE NEXT FEW DAYS...WILL
STAY ON THE WARM SIDE OF GUIDANCE BASED ON RECENT TRENDS. TOMORROW
WILL LIKELY BE THE COOLEST DAY OUT OF THE NEXT 7 UNLESS A LOCATION
IS LUCKY ENOUGH TO GET RELIEF FROM RAINFALL. HIGHS ON SATURDAY
WILL BE NEAR NORMAL ACROSS MOST OF THE AREA...GENERALLY 92 TO 94
DEGREES...ALTHOUGH PORTIONS OF EAST ARKANSAS WILL CLIMB BACK INTO
THE UPPER 90S AS A THERMAL RIDGE BUILDS EAST.
THE WARMING TREND WILL CONTINUE THROUGH THE WEEKEND AND INTO NEXT
WEEK AS A RIDGE STRENGTHENS OVER THE PLAINS AND SURFACE HIGH
PRESSURE ENCOMPASSES MUCH OT THE DEEP SOUTH. NO ORGANIZED WEATHER
IS ON THE SCOPE...ALTHOUGH WE WILL LIKELY SEE CLIMATOLOGICAL 20-30
PERCENT POPS NEARLY EVERY AFTERNOON. HIGHS FOR MOST OF THE
UPCOMING WORK WEEK WILL BE BETWEEN 95 AND 100 DEGREES.
&&
.AVIATION...
12Z TAF CYCLE
VFR CONDITIONS SHOULD CONTINUE FOR MUCH OF THE FORECAST PERIOD.
SOME SHOWERS AND THUNDERSTORMS MAY DEVELOP THIS AFTERNOON WITH THE
BEST CHANCE OVER NORTH MISSISSIPPI WHICH COULD PRODUCE BRIEF
PERIODS OF MVFR CEILINGS AND VISIBILITIES. WINDS WILL START OUT
FROM THE SOUTHWEST THIS MORNING BUT GRADUALLY SHIFT TOE NORTHWEST
THIS AFTERNOON AND EVENTUALLY TO THE NORTH OVERNIGHT.
ARS
&&
.PRELIMINARY POINT TEMPS/POPS...
MEM 101 78 96 74 / 20 10 10 0
MKL 95 72 93 68 / 20 10 10 0
JBR 102 73 98 72 / 10 0 0 0
TUP 94 74 92 71 / 50 20 20 10
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...HEAT ADVISORY UNTIL 1 AM CDT SATURDAY FOR CLAY-GREENE-LAWRENCE-
RANDOLPH.
EXCESSIVE HEAT WARNING UNTIL 1 AM CDT SATURDAY FOR CRAIGHEAD-
CRITTENDEN-CROSS-LEE AR-MISSISSIPPI-PHILLIPS-POINSETT-ST.
FRANCIS.
MO...HEAT ADVISORY UNTIL 1 AM CDT SATURDAY FOR DUNKLIN-PEMISCOT.
MS...HEAT ADVISORY UNTIL 1 AM CDT SATURDAY FOR CALHOUN-CHICKASAW-
ITAWAMBA-LEE MS-MONROE-PONTOTOC-PRENTISS-TISHOMINGO-UNION.
EXCESSIVE HEAT WARNING UNTIL 1 AM CDT SATURDAY FOR ALCORN-BENTON
MS-COAHOMA-DESOTO-LAFAYETTE-MARSHALL-PANOLA-QUITMAN-
TALLAHATCHIE-TATE-TIPPAH-TUNICA-YALOBUSHA.
TN...HEAT ADVISORY UNTIL 1 AM CDT SATURDAY FOR CARROLL-DECATUR-HARDIN-
HENDERSON-HENRY-LAKE-OBION-WEAKLEY.
EXCESSIVE HEAT WARNING UNTIL 1 AM CDT SATURDAY FOR CHESTER-
CROCKETT-DYER-FAYETTE-GIBSON-HARDEMAN-HAYWOOD-LAUDERDALE-
MADISON-MCNAIRY-SHELBY-TIPTON.
&&
$$
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1056 AM CDT FRI JUL 20 2012
.UPDATE...
ONLY MINOR GRID UPDATES TO INCREASE AREAWIDE DEW POINTS/RHS...AND
TO FOCUS HIGHER CHANCE POPS OVER THE SOUTHEASTERN FORECAST AREA
THIS AFTERNOON. HIGHER PVA RIDING AROUND THE SOUTHERN PERIPHERY OF
UPPER RIDGING CENTERED OVER THE WESTERN PLAINS IS CREATING THE
UNSETTLED WEATHER OFF THE COAST OF LOUISIANA. THE GENERAL
CONSENSUS AMONGST THE MODELS IS TO KEEP THE BULK OF THIS ENERGY
OVER LCH`S WESTERN CWA...TRAVELING FURTHER OFFSHORE. THUS...THERE
APPEARS TO BE A STARK DELINEATION CONCERNING RAINFALL OVER EXTREME
EASTERN TEXAS/NW GULF VERSUS MUCH DRIER CONDITIONS (PRECIPITATION-
WISE) FOR OUR REGION GOING INTO THE WEEKEND. INCREASING NEAR 2
INCH PWATS FROM THE WESTERN ADVECTION OF LOUISIANA`S MOIST AIR
MASS PER MID-LEVEL EASTERLY FLOW. FOR TODAY...LOW 90F CONVECTIVE
TEMPERATURES WITHIN A MOISTENING AND HEATED MID 90F EARLY AFTERNOON
ENVIRONMENT ENSURES AT LEAST 20 PERCENT MID-LATE AFTERNOON SHOWER/
ISOLATED STORM COVERAGE. 31
&&
.PREV DISCUSSION... /ISSUED 631 AM CDT FRI JUL 20 2012/
DISCUSSION...
SEE AVIATION FOR 12Z TAF DISCUSSION
AVIATION...
A FEW LOW CLOUDS ACROSS THE REGION THIS MORNING BUT VFR CONDITIONS
ARE EXPECTED FOR THE BULK OF THE TAF VALID PERIOD. SOUTHWESTERLY
WINDS ARE EXPECTED TODAY AS HIGH PRESSURE CONTINUES TO BUILD
ACROSS THE NORTHERN GULF OF MEXICO. THUNDERSTORMS ARE EXPECTED TO
BE RATHER ISOLATED AS SUBSIDENCE ALOFT WILL HELP TO CAP CONVECTION
THIS AFTERNOON. WITH THIS IN MIND HAVE REMOVED THE MENTION OF VCSH
FOR TODAY AS COVERAGE WILL BE TOO LOW TO WARRANT A MENTION IN THE
TAFS. 38
PREV DISCUSSION... /ISSUED 418 AM CDT FRI JUL 20 2012/
DISCUSSION...
RADAR AND SATELLITE LESS ACTIVE THAN LAST NIGHT. HIGH PRESSURE
RIDGE ALOFT OVER SE TX TODAY AND TOMORROW BRINGING SOME
SUBSIDENCE. HAVE REDUCED POPS FOR TODAY DOWN TO 20 PERCENT
AREAWIDE FOR THE AFTERNOON. WARMING TEMPERATURES ALOFT FROM
SUBSIDENCE BETWEEN 900-850MB SHOULD HELP CAP SOME CONVECTION AND
RESULT IN LESS COVERAGE THAN YESTERDAY. HRRR REFLECTIVITY FIELD
FORECAST COVERAGE IS VERY SPARSE AND NEAR COAST THIS AFTERNOON.
STILL SEEING MOIST PWAT AIR OVER SE TX FCST BY GFS IN THE 1.8 TO
NEAR 2.0 INCH RANGE. GFS FCST SOUNDINGS INDICATE CONVECTIVE TEMPS
IN THE MID 90S WHICH WILL BE REACHED AT KIAH LATE IN THE AFTN.
OTHERWISE HOT AND HUMID WITH AFTERNOON HEAT INDICES IN THE 100-105
RANGE.
UPPER DISTURBANCE ROTATING AROUND THE LARGER UPPER HIGH OVER KS/OK
WILL APPROACH THE CWA BY SUNDAY. GFS DOES HAVE CONVECTIVE FEEDBACK
LOOKING PCPN BULLSEYE APPROACHING SE TX ON SAT NIGHT/SUNDAY
MORNING. OTHER MODELS ARE DRY. THIS FEATURE SEEMS TO ORIGINATE
FROM CONVECTION OCCURRING EARLIER TONIGHT IN TENNESSEE. NOT OUT OF
THE QUESTION THAT SOMETHING WILL ROTATE INTO OUR AREA...AS A
RESULT I INCLUDED SLIGHT CHC TSRA FOR OVERNIGHT HOURS SAT INTO
SUNDAY MORNING. WILL NEED TO WATCH THIS FOR POSSIBLE CHANGES
DEPENDING UPON LATER OBS AND MODEL TRENDS. THIS
TROUGH/DISTURBANCE ROTATES THROUGH SE TX QUICKLY AND IS IN WEST TX
BY MONDAY NIGHT. TUTT LOW OVER CUBA/JAMAICA TONIGHT MOVES TOWARDS
THE NW GULF OF MEXICO BY EARLY NEXT WEEK...LOW POPS ARE THE RESULT
IN THE EXTENDED FORECAST SO FAR.
TENDED WARMER THAN GFS MOS GUIDANCE AGAIN THIS PACKAGE FOR MAX
TEMPS. OPERATIONAL MOS AGAIN ON THE COOL SIDE OF THE ENSEMBLES.
ETA MOS/ECM MOS ARE WARMER AND HAVE BEEN PERFORMING BETTER SO OUR
CONTINUED WARMER THAN GUIDANCE TREND FOR THE NEXT FEW DAYS SEEMS A
GOOD IDEA.
ZONES MAY BE A TAD LATE DUE TO SOME AWIPS ISSUES EARLIER THIS
MORNING...BUT NOT TOO LATE. 04
MARINE...
LIGHT SOUTHWEST TO WEST WINDS WILL CONTINUE TODAY ACROSS THE COASTAL
WATERS AS HIGH PRESSURE CONTINUES TO BUILD ACROSS HE GULF OF
MEXICO. ISOLATED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO CONTINUE
THROUGH EARLY NEXT WEEK AS A TUTT APPROACHES FROM THE EAST. 38
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 97 78 98 76 97 / 20 10 10 10 20
HOUSTON (IAH) 95 78 96 76 93 / 20 20 20 20 20
GALVESTON (GLS) 92 82 91 81 92 / 30 30 20 20 20
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...31
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
631 AM CDT FRI JUL 20 2012
.DISCUSSION...
SEE AVIATION FOR 12Z TAF DISCUSSION
&&
.AVIATION...
A FEW LOW CLOUDS ACROSS THE REGION THIS MORNING BUT VFR CONDITIONS
ARE EXPECTED FOR THE BULK OF THE TAF VALID PERIOD. SOUTHWESTERLY
WINDS ARE EXPECTED TODAY AS HIGH PRESSURE CONTINUES TO BUILD
ACROSS THE NORTHERN GULF OF MEXICO. THUNDERSTORMS ARE EXPECTED TO
BE RATHER ISOLATED AS SUBSIDENCE ALOFT WILL HELP TO CAP CONVECTION
THIS AFTERNOON. WITH THIS IN MIND HAVE REMOVED THE MENTION OF VCSH
FOR TODAY AS COVERAGE WILL BE TOO LOW TO WARRANT A MENTION IN THE
TAFS. 38
&&
.PREV DISCUSSION... /ISSUED 418 AM CDT FRI JUL 20 2012/
DISCUSSION...
RADAR AND SATELLITE LESS ACTIVE THAN LAST NIGHT. HIGH PRESSURE
RIDGE ALOFT OVER SE TX TODAY AND TOMORROW BRINGING SOME
SUBSIDENCE. HAVE REDUCED POPS FOR TODAY DOWN TO 20 PERCENT
AREAWIDE FOR THE AFTERNOON. WARMING TEMPERATURES ALOFT FROM
SUBSIDENCE BETWEEN 900-850MB SHOULD HELP CAP SOME CONVECTION AND
RESULT IN LESS COVERAGE THAN YESTERDAY. HRRR REFLECTIVITY FIELD
FORECAST COVERAGE IS VERY SPARSE AND NEAR COAST THIS AFTERNOON.
STILL SEEING MOIST PWAT AIR OVER SE TX FCST BY GFS IN THE 1.8 TO
NEAR 2.0 INCH RANGE. GFS FCST SOUNDINGS INDICATE CONVECTIVE TEMPS
IN THE MID 90S WHICH WILL BE REACHED AT KIAH LATE IN THE AFTN.
OTHERWISE HOT AND HUMID WITH AFTERNOON HEAT INDICES IN THE 100-105
RANGE.
UPPER DISTURBANCE ROTATING AROUND THE LARGER UPPER HIGH OVER KS/OK
WILL APPROACH THE CWA BY SUNDAY. GFS DOES HAVE CONVECTIVE FEEDBACK
LOOKING PCPN BULLSEYE APPROACHING SE TX ON SAT NIGHT/SUNDAY
MORNING. OTHER MODELS ARE DRY. THIS FEATURE SEEMS TO ORIGINATE
FROM CONVECTION OCCURRING EARLIER TONIGHT IN TENNESSEE. NOT OUT OF
THE QUESTION THAT SOMETHING WILL ROTATE INTO OUR AREA...AS A
RESULT I INCLUDED SLIGHT CHC TSRA FOR OVERNIGHT HOURS SAT INTO
SUNDAY MORNING. WILL NEED TO WATCH THIS FOR POSSIBLE CHANGES
DEPENDING UPON LATER OBS AND MODEL TRENDS. THIS
TROUGH/DISTURBANCE ROTATES THROUGH SE TX QUICKLY AND IS IN WEST TX
BY MONDAY NIGHT. TUTT LOW OVER CUBA/JAMAICA TONIGHT MOVES TOWARDS
THE NW GULF OF MEXICO BY EARLY NEXT WEEK...LOW POPS ARE THE RESULT
IN THE EXTENDED FORECAST SO FAR.
TENDED WARMER THAN GFS MOS GUIDANCE AGAIN THIS PACKAGE FOR MAX
TEMPS. OPERATIONAL MOS AGAIN ON THE COOL SIDE OF THE ENSEMBLES.
ETA MOS/ECM MOS ARE WARMER AND HAVE BEEN PERFORMING BETTER SO OUR
CONTINUED WARMER THAN GUIDANCE TREND FOR THE NEXT FEW DAYS SEEMS A
GOOD IDEA.
ZONES MAY BE A TAD LATE DUE TO SOME AWIPS ISSUES EARLIER THIS
MORNING...BUT NOT TOO LATE. 04
MARINE...
LIGHT SOUTHWEST TO WEST WINDS WILL CONTINUE TODAY ACROSS THE COASTAL
WATERS AS HIGH PRESSURE CONTINUES TO BUILD ACROSS HE GULF OF
MEXICO. ISOLATED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO CONTINUE
THROUGH EARLY NEXT WEEK AS A TUTT APPROACHES FROM THE EAST. 38
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 97 77 98 76 97 / 20 10 10 10 20
HOUSTON (IAH) 95 77 96 76 93 / 20 20 20 20 20
GALVESTON (GLS) 92 81 91 81 92 / 20 20 20 20 20
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...04
AVIATION/MARINE...38
FOR FREQUENTLY ASKED QUESTIONS ABOUT THE AREA FORECAST DISCUSSION
VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY/GENERAL/AFD_FAQS.PHP (ALL LOWER CASE)
AREA FORECAST DISCUSSION
NWS TUCSON AZ
305 PM MST FRI JUL 20 2012
.SYNOPSIS...MONSOONAL MOISTURE HAS RETURNED AND THIS WILL LEAD TO
SCATTERED AFTERNOON AND EVENING THUNDERSTORMS THIS WEEKEND INTO
EARLY NEXT WEEK.
&&
.DISCUSSION...MID-AFTERNOON DOPPLER RADAR SHOWED ISOLATED SHOWERS
AND THUNDERSTORMS ACROSS THE AREA. SENT UP A BALLOON LATE THIS
MORNING TO SEE IF THERE HAVE BEEN ANY CHANGES TO THE PROFILE. IT DID
SHOW AN INCREASE IN MID-LEVEL STEERING FLOW AND THE STORMS TODAY ARE
MOVING AROUND 12-20 MPH. THIS WILL LIMIT FLASH FLOODING POTENTIAL
BUT WITH INVERTED-V PROFILE...THE THREAT OF SEEING ISOLATED SEVERE
WINDS IS THERE. SPC HAS CENTRAL PORTIONS OF THE AREA UNDER A SLIGHT
RISK. ACTIVITY OVER THE NEXT 6 HOURS...WILL BASICALLY BE ACROSS
PINAL/PIMA/SANTA CRUZ COUNTIES...WITH ISOLATED GRAHAM/COCHISE
COUNTIES. INTERESTING TO NOTE THAT LATER TONIGHT THE UOFA WRF MODELS
AND THE HRRR MODEL ARE ROTATING STORMS FROM SW NEW MEXICO/NW
CHIHUAHUA INTO THE EASTERN ZONES. WITH THE POSSIBILITY THAT THIS
MIGHT HAPPEN...HAVE KEPT POPS UP IN THE EASTERN ZONES DURING THE
OVERNIGHT PERIOD. THE NEXT SHIFT WILL MONITOR TRENDS AND MAY END UP
DOING AN UPDATE TO THE FORECAST.
APPROACHING INVERTED TROF WILL KEEP THE AREA ACTIVITY THIS WEEKEND
WITH THE THREAT OF WET MICROBURSTS EACH DAY. TEMPERATURES THIS
WEEKEND FOR THE MOST PART WILL BE AT OR SLIGHTLY BELOW NORMAL.
MODELS STILL KEEP THE AREA ACTIVE ON MONDAY AND THEN GRADUALLY BRING
DRIER AIR INTO THE AREA...THUS LIMITING DAILY THUNDERSTORMS BELOW
STANDARD MONSOON FORECAST...GENERALLY JUST ISOLATED THUNDERSTORMS.
TEMPERATURES WILL BE AROUND NORMAL NEXT WEEK.
&&
.AVIATION...ISOLD-SCT TSRA/SHRA THIS AFTERNOON BECOMING MORE
WIDESPREAD THIS EVENING THEN ISOLD -TSRA/-SHRA 06Z-12Z SATURDAY.
SCT-BKN MID LEVEL CLOUDS WITH BASES 8-10K FT EXPECTED OVER THE NEXT
24 HOURS. BRIEF WIND GUSTS APPROACHING 45 KTS WITH THE STRONGEST
TSRA. OTHERWISE...VFR CONDITIONS AND SURFACE WIND GENERALLY LESS
THAN 10 KTS THRU SATURDAY AFTERNOON OR 21/20Z. AVIATION DISCUSSION
NOT UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...EXPECT SCATTERED SHOWERS AND THUNDERSTORMS ACROSS
SOUTHEAST ARIZONA TODAY AND AGAIN TOMORROW AS AN UPPER LEVEL
DISTURBANCE MOVES ACROSS THE AREA FROM THE EAST BRINGING WITH IT
PLENTY OF MOISTURE. SLIGHTLY DRIER AIR WILL THEN MOVE INTO THE AREA
FOR THE START OF NEXT WEEK...BUT ENOUGH MOISTURE WILL REMAIN FOR
MORE ISOLATED MAINLY AFTERNOON AND EVENING THUNDERSTORMS.
&&
.CLIMATE...THE QUICK MOVING THUNDERSTORM THAT HIT THE TUCSON
INTERNATIONAL AIRPORT BETWEEN 145 PM AND 215 PM...DROPPED 0.34" INTO
THE RAIN GAUGE. THUS AS OF 245 PM THE MONSOON AND SUMMER RAINFALL
TOTALS ARE UP TO 4.19"...WHICH RANK AS THE 2ND WETTEST MONSOON AND
3RD WETTEST SUMMER TO DATE. THE TOTAL FOR JULY IS UP TO 3.85" WHICH
RANKS AS 2ND WETTEST TO DATE AND 19TH WETTEST FOR ENTIRE MONTH OF
JULY. LASTLY...THE 2012 TOTAL IS UP TO 4.87" WHICH RANKS AS 40TH
WETTEST TO DATE.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
$$
WEATHER.GOV/TUCSON
AREA FORECAST DISCUSSION
NWS TUCSON AZ
250 PM MST FRI JUL 20 2012
.SYNOPSIS...MONSOONAL MOISTURE HAS RETURNED AND THIS WILL LEAD TO
SCATTERED AFTERNOON AND EVENING THUNDERSTORMS THIS WEEKEND INTO
EARLY NEXT WEEK.
&&
.DISCUSSION...MID-AFTERNOON DOPPLER RADAR SHOWED ISOLATED SHOWERS
AND THUNDERSTORMS ACROSS THE AREA. SENT UP A BALLOON LATE THIS
MORNING TO SEE IF THERE HAVE BEEN ANY CHANGES TO THE PROFILE. IT DID
SHOW AN INCREASE IN MID-LEVEL STEERING FLOW AND THE STORMS TODAY ARE
MOVING AROUND 12-20 MPH. THIS WILL LIMIT FLASH FLOODING POTENTIAL
BUT WITH INVERTED-V PROFILE...THE THREAT OF SEEING ISOLATED SEVERE
WINDS IS THERE. SPC HAS CENTRAL PORTIONS OF THE AREA UNDER A SLIGHT
RISK. ACTIVITY OVER THE NEXT 6 HOURS...WILL BASICALLY BE ACROSS
PINAL/PIMA/SANTA CRUZ COUNTIES...WITH ISOLATED GRAHAM/COCHISE
COUNTIES. INTERESTING TO NOTE THAT LATER TONIGHT THE UOFA WRF MODELS
AND THE HRRR MODEL ARE ROTATING STORMS FROM SW MEXICO/NW CHIHUAHUA
INTO THE EASTERN ZONES. WITH THE POSSIBILITY THAT THIS MIGHT
HAPPEN...HAVE KEPT POPS UP IN THE EASTERN ZONES DURING THE OVERNIGHT
PERIOD. THE NEXT SHIFT WILL MONITOR TRENDS AND MAY END UP DOING AN
UPDATE TO THE FORECAST.
APPROACHING INVERTED TROF WILL KEEP THE AREA ACTIVITY THIS WEEKEND
WITH THE THREAT OF WET MICROBURSTS EACH DAY. TEMPERATURES THIS
WEEKEND FOR THE MOST PART WILL BE AT OR SLIGHTLY BELOW NORMAL.
MODELS STILL KEEP THE AREA ACTIVE ON MONDAY AND THEN GRADUALLY BRING
DRIER AIR INTO THE AREA...THUS LIMITING DAILY THUNDERSTORMS BELOW
STANDARD MONSOON FORECAST...GENERALLY JUST ISOLATED THUNDERSTORMS.
TEMPERATURES WILL BE AROUND NORMAL NEXT WEEK.
&&
.AVIATION...ISOLD-SCT TSRA/SHRA THIS AFTERNOON BECOMING MORE
WIDESPREAD THIS EVENING THEN ISOLD -TSRA/-SHRA 06Z-12Z SATURDAY.
SCT-BKN MID LEVEL CLOUDS WITH BASES 8-10K FT EXPECTED OVER THE NEXT
24 HOURS. BRIEF WIND GUSTS APPROACHING 45 KTS WITH THE STRONGEST
TSRA. OTHERWISE...VFR CONDITIONS AND SURFACE WIND GENERALLY LESS
THAN 10 KTS THRU SATURDAY AFTERNOON OR 21/20Z. AVIATION DISCUSSION
NOT UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...EXPECT SCATTERED SHOWERS AND THUNDERSTORMS ACROSS
SOUTHEAST ARIZONA TODAY AND AGAIN TOMORROW AS AN UPPER LEVEL
DISTURBANCE MOVES ACROSS THE AREA FROM THE EAST BRINGING WITH IT
PLENTY OF MOISTURE. SLIGHTLY DRIER AIR WILL THEN MOVE INTO THE AREA
FOR THE START OF NEXT WEEK...BUT ENOUGH MOISTURE WILL REMAIN FOR
MORE ISOLATED MAINLY AFTERNOON AND EVENING THUNDERSTORMS.
&&
.CLIMATE...THE QUICK MOVING THUNDERSTORM THAT HIT THE TUCSON
INTERNATIONAL AIRPORT BETWEEN 145 PM AND 215 PM...DROPPED 0.34" INTO
THE RAIN GAUGE. THUS AS OF 245 PM THE MONSOON AND SUMMER RAINFALL
TOTALS ARE UP TO 4.19"...WHICH RANK AS THE 2ND WETTEST MONSOON AND
3RD WETTEST SUMMER TO DATE. THE TOTAL FOR JULY IS UP TO 3.85" WHICH
RANKS AS 2ND WETTEST TO DATE AND 19TH WETTEST FOR ENTIRE MONTH OF
JULY. LASTLY...THE 2012 TOTAL IS UP TO 4.87" WHICH RANKS AS 40TH
WETTEST TO DATE.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
$$
WEATHER.GOV/TUCSON
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1040 AM MDT FRI JUL 20 2012
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 400 AM MDT FRI JUL 20 2012
TODAY: A FEW LIGHT SHOWERS AND EMBEDDED THUNDERSTORMS CONTINUED
TO MOVE NORTH-NORTHEASTWARD ACROSS WEST-CENTRAL AND NORTHEAST UTAH
EARLY THIS MORNING. NAM AND HRRR SEEMED TO HANDLE THIS ACTIVITY
WELL AND BOTH INDICATED THE POSSIBILITY OF SOME ISOLATED CELLS
LINGERING THROUGH 15Z.
HIGH PRESSURE CENTERED OVER THE CENTRAL HIGH PLAINS WILL CONTINUE
TO CARRY MONSOON MOISTURE NORTHWARD DURING THE REMAINDER OF THE
DAY. THE DEEPEST MOISTURE WILL BE OVER EASTERN UTAH...BUT MOISTURE
LEVELS SHOULD CONTINUE TO RISE OVER WESTERN COLORADO. DAYTIME
WARMING WORKING ON MONSOON MOISTURE WILL BRING SCATTERED TO
NUMEROUS THUNDERSTORMS TO THE MOUNTAIN AREAS FROM LATE MORNING
INTO THE EVENING. AS DIURNAL CIRCULATIONS BREAK DOWN LATER IN THE
AFTERNOON...EXPECT WIDELY SCATTERED STORMS TO IMPACT THE LOWER
ELEVATIONS.
INCREASED CLOUD AND SHOWER/STORM COVERAGE WILL SHOULD BRING HIGHS
DOWN A FEW DEGREES ACROSS THE REGION.
TONIGHT THROUGH SUNDAY: EASTERN UTAH AND WESTERN COLORADO WILL
CONTINUE TO SIT ON THE WESTERN SIDE OF THE LARGE DOMINATING HIGH
PRESSURE RIDGE PARKED OVER THE CENTRAL CONUS. THIS WILL KEEP US IN
A FAVORABLE POSITION FOR THE MONSOONAL MOISTURE SURGE TO PERSIST
THROUGH THE WEEKEND. THE RIDGE DOES BECOME FLATTENED A LITTLE AS
PACIFIC ENERGY MOVES ACROSS SOUTHWEST CANADA. BUT THIS WILL HAVE
LITTLE IMPACT TO OUR SENSIBLE WEATHER. THE AREA WILL SEE A GRADUAL
INCREASE IN MOISTURE THROUGH SUNDAY. DIURNALLY FAVORED SHOWERS AND
THUNDERSTORMS WILL DEVELOP EACH DAY...WITH SOME ACTIVITY
CONTINUING OVERNIGHT. LOCALIZED HEAVY RAIN WILL BE POSSIBLE. ALSO
IF ANY WEAK BUT UNRESOLVED DISTURBANCES ROTATE ACROSS THE AREA...
SHOWERS AND THUNDERSTORMS WILL BE ENHANCED.
WITH THE INCREASED CLOUD COVER AND BETTER CHANCE OF RAIN...HIGH
TEMPERATURES WILL BE DOWN A FEW DEGREES AS COMPARED TO THE LAST FEW
DAYS.
.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 400 AM MDT FRI JUL 20 2012
THE BROAD AREA OF HIGH PRESSURE INDICATED TO REMAIN QUASI-
STATIONARY OVER THE CENTRAL PLAINS THROUGH NEXT WEEK. AS A
RESULT...MONSOON MOISTURE WILL CONTINUE TO MOVE OVER THE REGION
UNABATED RESULTING IN LARGELY DIURNALLY DRIVEN SHOWERS AND
THUNDERSTORMS EACH DAY. TEMPERATURES WILL HOVER NEAR NORMAL FOR
THIS TIME OF YEAR.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1029 AM MDT FRI JUL 20 2012
VFR CONDITIONS WILL PREVAIL ACROSS THE REGION FOR THE REMAINDER OF
THIS MORNING. THIS AFTERNOON DAYTIME HEATING WILL BRING ANOTHER
ROUND OF SHOWERS AND THUNDERSTORMS. BY MIDAFTERNOON...SCATTERED TO
NUMEROUS THUNDERSTORM COVERAGE WILL RESULT IN FREQUENT MOUNTAIN
OBSCURATIONS AND GUSTY OUTFLOW WINDS TO 45 MPH. REGIONAL AIRPORTS
FACE THE BEST CHANCE OF THUNDERSTORMS FROM 21Z TO 03Z WITH THOSE
IN CLOSE PROXIMITY TO HIGHER TERRAIN TO THE SOUTH FAVORED. THESE
STORMS WILL BRING BRIEF MVFR CIGS AND/OR VSBY IN HEAVY RAIN.
SHOWERS AND THUNDERSTORMS WILL DECREASE...BUT NOT FULLY DIMINISH
OVERNIGHT. LITTLE CHANGE IS EXPECTED SATURDAY.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
SHORT TERM...NL/EH
LONG TERM...NL
AVIATION...MC
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
221 PM EDT FRI JUL 20 2012
.PREV DISCUSSION... /ISSUED 1140 AM EDT FRI JUL 20 2012/
UPDATE...
HAVE MADE SEVERAL MINOR TWEAKS TO GRIDS THIS MORNING...MOSTLY TO
ACCOUNT FOR HOURLY TRENDS WITH TEMPS DEWPOINTS AND POPS. SPC STILL
HAS MOST OF THE AREA IN A SLIGHT RISK FOR DAY1...AND POPS ACROSS
NORTH AND CENTRAL GEORGIA REMAIN VERY HIGH THIS AFTERNOON TO
ACCOUNT FOR CONVECTIVE DEVELOPMENT. THE CONCERN IS THAT...WITH THE
EXCEPTION OF THE MOST RECENT HRRR RUNS...NONE OF THE HIRES MODELS
HAD THE MCS REMNANTS LASTING SO LONG THIS MORNING. CONDITIONS ARE
PRETTY STABLE ACROSS NORTH GEORGIA RIGHT NOW WITH CAPES BELOW 500
IN THE RAIN-COOLED AIRMASS. HOWEVER...BEHIND THE CIRRUS SHIELD...
TEMPS ARE ALREADY STARTING TO INCREASE AND AT AFD TIME AM STARTING
TO SEE CONVECTION FIRE NEAR CHA. THINK THAT IN THE END THE
INSTABILITY WILL CATCH UP. 12Z KFFC MODIFIED SOUNDING WITH LOWER
70S DEWPOINTS AND A HIGH IN THE UPPER 80S GIVES OVER 3000 J/KG
SBCAPE SO AT THIS POINT STILL EXPECT NUMEROUS SHOWERS AND
THUNDERSTORMS TO DEVELOP WITH SOME POSSIBLY SEVERE. POPS MAY
ACTUALLY NEED TO BE INCREASED INTO THE AFTERNOON ONCE WE GET A
HANDLE ON LOCATION AND MOVEMENT.
TDP
PREV DISCUSSION... /ISSUED 741 AM EDT FRI JUL 20 2012/
SHORT TERM /TODAY THROUGH SATURDAY/...
/ISSUED AT 406 AM EDT FRI JUL 20 2012/
INITIAL CONCERN IS THE CONVECTIVE COMPLEX (MCS) SPREADING SOUTHWARD
FROM TN THIS MORNING. REGIONAL RADARS...CLOUD TOP TEMPERATURES NOTED
ON SATELLITE AND LIGHTNING DATA ALL SUGGEST THE STRONGER STORMS WILL
PUSH INTO NORTH AL... WITH A WEAKENING TREND NOTED FOR CONVECTION
MOVING INTO NORTH GA. THEREFORE...EXPECT MAINLY SHOWERS TO PUSH
ACROSS NORTH GA THIS MORNING...TO INCLUDE METRO ATLANTA...BEFORE
DISSIPATING. HOWEVER...CANNOT RULE OUT A THUNDERSTORM OR TWO WITH
THIS ACTIVITY...SO WILL MENTION A SLIGHT CHANCE OF THUNDER THROUGH
THE MORNING HOURS. THE GREATER THUNDERSTORM THREAT WILL OCCUR DURING
AFTERNOON HEATING AS AN ACTIVE UPPER TROUGH INTERACTS WITH A MOIST
(NEAR 2 INCH PW`S) AND UNSTABLE AIR MASS (1500-2500 J/KG CAPE) TO
PRODUCE SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS THIS
AFTERNOON AND EVENING. REMNANT OUTFLOW BOUNDARIES FROM THIS
MORNING`S MCS SHOULD HELP PROVIDE A FOCUS FOR STORM DEVELOPMENT...
AND THIS SHOULD OCCUR MAINLY OVER NORTH GA WHERE BOUNDARIES SHOULD
BE LINGERING. A SLIGHT INCREASE IN VERTICAL WIND SHEAR FROM A
STRENGTHENING SW MID LEVEL FLOW AHEAD OF A COLD FRONT PUSHING INTO
TN TODAY COULD AID IN STRONG TO SEVERE STORM DEVELOPMENT...
ESPECIALLY IF ENHANCED BY WEAK DISTURBANCES TRAVERSING THE UPPER
TROUGH TODAY. SPC HAS PLACED NORTH GA IN A SLIGHT RISK TODAY...
MAINLY NORTH OF A HAMILTON TO MONTICELLO TO WASHINGTON LINE. THE
PRIMARY THREAT WILL BE DAMAGING WIND GUSTS... BUT ALSO EXPECT
FREQUENT LIGHTNING...HEAVY RAIN AND SMALL HAIL WITH THE STRONGER
STORMS. ANY SLOW MOVING STORMS WILL PRODUCE LOCALLY HEAVY RAIN...
AND COULD RESULT IN BRIEF LOCALIZED FLASH FLOODING. MODELS AGREE ON
STALLING THE COLD FRONT OVER TN TONIGHT... THEN SAGGING THE FRONT
INTO NORTH GA ON SATURDAY WHERE IT LIKELY LINGERS BEFORE PUSHING
BACK NORTH ON SUNDAY. WILL CONTINUE TO SHOW A SLIGHT CHANCE OF
THUNDER OVERNIGHT... WITH LIKELY POPS WARRANTED AGAIN ON SATURDAY AS
THE ACTIVE UPPER TROUGH INTERACTS WITH THE FRONTAL BOUNDARY.
INCREASING CLOUDS AND CONVECTIVE ACTIVITY SHOULD HOLD DAYTIME HIGHS
DOWN INTO THE 80S FOR MOST AREAS TODAY AND AGAIN ON SATURDAY. HAVE
LEANED TOWARD A MAV AND MET BLEND THROUGH THE SHORT TERM AS MAV
LOOKED A BIT WARM AND MET COOL FOR HIGHS. THE LOWS WERE VERY CLOSE
AND LOOKED REASONABLE.
39
LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
/ISSUED AT 406 AM EDT FRI JUL 20 2012/
FRONTAL BOUNDARY WHICH SAGS OVER GA SAT WILL BEGIN TO PUSH BACK
NORTHWARD SAT NIGHT AS BERMUDA LIKE RIDGE BUILDS OFF THE GA/CAROLINA
COAST. THE BOUNDARY KEEPS A DECENT AMOUNT OF MOISTURE AND A FOCUSING
MECHANISM OVER THE AREA THROUGH MONDAY AFTERNOON BEFORE DIMINISHING
UNDER THE BUILDING RIDGE. SHOULD CONTINUE TO SEE A MOSTLY DIURNAL
CONVECTIVE TREND IN THE EXTENDED AS MOISTURE FROM THE GULF ROTATES
UP INTO THE AREA UNDER THE SURFACE RIDGE THROUGH DAY 7. EVEN WITH
THE HIGH IN PLACE...PLENTY OF LOW LEVEL MOISTURE WILL SUPPORT
DIURNAL CONVECTION EACH DAY. FORECAST PRECIPITABLE WATER VALUES
STILL SHOWING NEAR 2.0 INCH VALUES THROUGH THE MIDDLE OF NEXT
WEEK...AND WITH K-INDEX VALUES IN THE MID TO UPPER 30S...HEAVY RAIN
STILL REMAINS A THREAT. WIDESPREAD 1-1.25 INCHES ARE EXPECTED
THROUGH SUNDAY AFTERNOON...WITH LOCALLY HEAVIER AMOUNTS ASSOCIATED
WITH AREAS OF MODERATE TO STRONG CONVECTION. BY WEDNESDAY...LOW
PRESSURE DEEPENING OVER THE CANADIAN MARITIMES WILL DRAG ANOTHER
FRONTAL BOUNDARY THROUGH THE MID ATLANTIC STATES...WITH TROUGH
EXTENDING INTO NORTH GEORGIA. THE MODELS DO DIFFER A BIT ON JUST HOW
FAR SOUTH THIS FRONTAL BOUNDARY MOVES SO WILL CONTINUE WITH
DIURNALLY DRIVEN CHANCE POPS THROUGH DAY 7.
AS FOR TEMPERATURES...THINGS SHOULD BE A BIT COOLER THIS WEEKEND
WITH HI TEMPS IN THE 80S TO LOW 90S DUE TO THE FRONTAL BOUNDARY AND
RAIN. TEMPS WILL BEGIN TO REBOUND MONDAY THROUGH WEDNESDAY WITH
TEMPS BACK INTO THE MID 90S BY WED/THU.
01
&&
.AVIATION...
18Z UPDATE...
EXPECT CONVECTION TO DEVELOP LATER THIS AFTERNOON AND EVENING...
AND HAVE KEPT TREND WITH TEMPO IN THE TAFS. ONCE THE CONVECTION
CLEARS...SHOULD SEE ANOTHER ROUND OF MVFR VSBY AND IFR CIGS
SATURDAY MORNING MUCH LIKE THIS MORNING WAS. SOME UNCERTAINTY AS
TO WHEN AND HOW FAST THE CIGS WILL LIFT. ANOTHER ROUND OF
CONVECTION EXPECTED FOR SATURDAY AFTERNOON. SOUTHWEST WINDS
GENERALLY 5-10KT THROUGH THE PERIOD EXCEPT IN THUNDERSTORMS.
//ATL CONFIDENCE...18Z UPDATE...
HIGH ON CONVECTION TODAY AND SATURDAY AFTERNOON...MEDIUM ON
IMPACTS TO ATL.
HIGH ON DEVELOPMENT OF IFR CIGS...MEDIUM ON TIMING OF ONSET AND
LIFTING.
HIGH ON WINDS AND VSBY.
TDP
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 88 72 84 70 / 70 60 60 40
ATLANTA 88 72 84 70 / 90 60 60 40
BLAIRSVILLE 84 69 82 66 / 70 60 60 40
CARTERSVILLE 89 71 85 70 / 80 60 60 40
COLUMBUS 89 73 88 72 / 70 50 60 30
GAINESVILLE 87 72 85 70 / 90 60 60 40
MACON 90 73 89 71 / 70 50 60 30
ROME 89 72 89 72 / 100 60 50 30
PEACHTREE CITY 88 71 85 70 / 70 60 60 40
VIDALIA 90 73 90 74 / 70 40 60 20
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1233 PM EDT FRI JUL 20 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 356 AM EDT FRI JUL 20 2012
AS A COLD FRONT AND WEAK SURFACE LOW DEPART THE AREA TODAY...A
WEAK SHORTWAVE WILL TRAVERSE THE REGION. THIS WILL HAVE A SMALL
CHANCE OF SPARKING AN ADDITIONAL SHOWER OR TWO THIS MORNING BEFORE
DRY WEATHER RETURNS TO THE FORECAST THROUGH THE WEEKEND.
ADDITIONALLY...SKIES WILL BE MOSTLY CLOUDY THROUGH THE FIRST HALF
OF THE DAY AS STRATOCUMULUS BUILDS INTO THE AREA IN THE CYCLONIC
FLOW. THIS WILL ALSO HELP KEEP TEMPERATURES DOWN TODAY...WITH SOME
AREAS STRUGGLING TO EVEN REACH THE 80 DEGREE MARK...A MAJOR SHIFT
FROM RECENT RECORD BREAKING HEAT. UNFORTUNATELY...THIS RESPITE
WILL BE SHORT LIVED...AS A RAPID WARMING TREND WILL FOLLOW FOR THE
WEEKEND...WITH TEMPERATURES BACK WELL INTO THE MID 90S BY SUNDAY
AS RIDGING ONCE AGAIN ASSERTS DOMINANCE ACROSS THE AREA. NORTHWEST
FLOW ALOFT NEXT WEEK SUGGESTS ONE OR MORE CHANCES FOR
THUNDERSTORMS...BUT PROBABILITIES REMAIN LOW AND UNCERTAIN AT THE
MOMENT.
&&
.NEAR TERM /TODAY/...
ISSUED AT 1039 AM EDT FRI JUL 20 2012
ISOLATED SHOWERS AND SPRINKLES ARE TAKING THEIR TIME ABOUT GOING
AWAY. RUC ISNT IN ANY RUSH TO GET RID OF THEM. WILL UPDATE TO KEEP
SOME PRECIP THROUGH MOST OF AFTERNOON. CURRENT POPS STILL LOOK
GOOD...BUT WILL MENTION ISOLATED SPRINKLES WEST.
TAKING TEMPS DOWN A CAT IN THE EAST AND CENTRAL WITH PRECIP AND
CLOUDS HANGING ON LONGEST THERE.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
ISSUED AT 356 AM EDT FRI JUL 20 2012
WITH SURFACE HIGH PRESSURE THE DOMINANT FEATURE THROUGHOUT THE
SHORT TERM...TEMPERATURES ARE THE ONLY SIGNIFICANT FORECAST ISSUE.
MODEL 850 TEMPS WARM SIGNIFICANTLY AND QUICKLY THROUGH THE SHORT
TERM...AND ARE BACK INTO THE LOW 20C RANGE BY SUNDAY.
LATELY...THIS HAS TRANSLATED EASILY INTO THE MID 90S...AND WHILE
RECENT RAINFALL HAS MADE A SMALL DENT INTO EXTREME DROUGHT...IT
WILL TAKE MUCH MORE THAN WHAT HAS ALREADY OCCURRED TO MITIGATE
IMPACT OF DROUGHT ON TEMPERATURES. EXPECT WE WILL BEGIN TO EASILY
OUTPACE MOS ONCE AGAIN. GENERALLY RAISED CONSENSUS AT LEAST A
COUPLE OF DEGREES ON MAXES...WITH CORRESPONDING BUT SLIGHTLY
SMALLER HIKES DURING THE OVERNIGHTS.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
ISSUED AT 255 AM EDT FRI JUL 20 2012
LONG RANGE MODELS AND ENSEMBLES SUGGEST UPPER RIDGE ACROSS THE
PLAINS EARLY NEXT WEEK WILL SETTLE SOUTHEAST ACROSS THE SOUTHERN
STATES MIDWEEK WITH CENTRAL INDIANA ON THE SOUTHERN FRINGES OF THE
WESTERLIES. MODELS ALSO HAVE QPF THROUGH MUCH OF THE EXTENDED.
UPPER THICKNESS PATTERN IS CONDUCIVE TO PERIODIC NORTHWEST TO
SOUTHEAST MOVING THUNDERSTORM COMPLEXES ACROSS THE LOWER GREAT LAKES
AND OHIO VALLEY...SO WILL LEAVE AT LEAST SMALL CHANCE POPS
THROUGHOUT THE EXTENDED. KEPT AFTERNOON TEMPERATURES A FEW DEGREES
ABOVE MOS AND THE CENTRAL REGION INITIALIZATION AS WE STILL HAVE A
WAY TO GO BEFORE THE DROUGHT LOSES ITS IMPACT.
&&
.AVIATION /DISCUSSION FOR THE 201800Z TAFS/...
ISSUED AT 1233 PM EDT FRI JUL 20 2012
WEAK UPPER DISTURBANCE DROPPING SOUTH THROUGH THE AREA MAY BRING A
FEW SCATTERED LIGHT SHOWERS TO THE KIND/KBMG VICINITY UNTIL ABOUT
201900Z.
OTHERWISE...DRIER AIR WORKING IN AT THE LOWER LEVELS COMBINED WITH
WEAK BOUNDARY LAYER HEATING SHOULD ALLOW FOR ANY LINGERING IFR
CEILINGS TO LIFT INTO AN MVFR DECK 015-020 BY OR SHORTLY AFTER
ISSUANCE TIME. CEILINGS SHOULD CONTINUE TO RISE THROUGHOUT THE
AFTERNOON...REACHING INTO THE VFR CATEGORY BY MID TO LATE
AFTERNOON...AND EVENTUALLY SCATTERING OUT FROM NORTH TO SOUTH DURING
THE EVENING.
SURFACE WINDS MAY OCCASIONALLY APPROACH 15 KTS FROM 010-030 HEADINGS
THROUGHOUT THE AFTERNOON AND EARLY EVENING HOURS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...NIELD
NEAR TERM...JK
SHORT TERM...NIELD
LONG TERM....MK
AVIATION...JAS
AREA FORECAST DISCUSSION
NWS GOODLAND KS
313 PM MDT FRI JUL 20 2012
.SHORT TERM...(THIS AFTERNOON THROUGH SATURDAY)
ISSUED AT 112 PM MDT FRI JUL 20 2012
LATEST WV IMAGERY AND RUC H5 ANALYSIS SHOW LARGE RIDGE ACROSS THE
INTER-MOUNTAIN WEST...CENTERED OVER EASTERN COLORADO. AT THE
SURFACE A WEAK SURFACE TROUGH IS IN PLACE WITH ITS MAIN AXIS ALONG
THE FRONT RANGE. SEVERAL WEAK SURFACE TROUGHS EXTEND EAST TOWARDS
THE KS CO BORDER.
WEAK SURFACE CONVERGENCE ALONG THESE SURFACE TROUGHS AND STEEP LOW
LEVEL LAPSE RATES HAVE LED TO THE DEVELOPMENT OF SHALLOW CUMULUS
EARLY THIS AFTERNOON. LARGE SCALE SUBSIDENCE COMBINED WITH A VERY
STRONG CAP WILL LIMIT UPDRAFT POTENTIAL...SO I HAVE KEPT ANY
THUNDERSTORM MENTION OUT OF FORECAST THROUGH TOMORROW.
WITH DRY CONDITIONS EXPECTED MAIN CONCERN IS NEAR RECORD
TEMPERATURES AND POSSIBLE FIRE WEATHER CONCERNS. WITH GUIDANCE
SHOWING AIRMASS SLIGHTLY ALOFT THAN TODAY...AND WINDS SHIFTING TO
THE SOUTH-SOUTHWEST TEMPERATURES ACROSS MUCH OF THE AREA COULD SEE
TEMPERATURES IN THE 105 TO 110 RANGE. RED FLAG CONDITIONS ARE NOT
CURRENTLY EXPECTED...WITH WINDS AROUND 20 MPH. IF RH VALUES WERE
TO DROP TO 10 PERCENT IN THE WEST THEN WE COULD MEET CRITERIA.
THIS IS NOT EXPECTED TO OCCUR...SO NO FIRE WEATHER HIGHLIGHTS
PLANNED FOR SATURDAY AT THIS POINT.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 313 PM MDT FRI JUL 20 2012
BROAD MID/UPPER RIDGE WILL REMAIN ANCHORED OVER THE CENTRAL PLAINS
THROUGH THE EARLY PART OF NEXT WEEK WITH A CONTINUATION OF
AFTERNOON TEMPS IN THE 100 TO 110 RANGE WITH APPARENT TEMPS
GENERALLY IN THE 103 TO 108 RANGE. AS SUCH...HAVE EXTENDED THE
HEAT ADVISORY THROUGH TUESDAY EVENING. HAD CONSIDERED UPGRADING AT
LEAST FAR EASTERN PORTIONS OF THE FORECAST AREA TO AN EXCESSIVE
HEAT WARNING GIVEN SLIGHTLY HIGHER HEAT INDICIES BUT THERE IS A
BIT OF UNCERTAINTY AS TO HOW FAR DEW POINTS WILL MIX EACH
AFTERNOON. IF THEY ARE LOWER THAN CURRENTLY FORECAST...APPARENT
TEMP VALUES WOULD BE CORRESPONDINGLY LOWER. FELT MORE CONFIDENT IN
KEEPING THE ADVISORY IN PLACE AND ALLOW FUTURE SHIFTS TO
REEVALUATE THE NEED FOR AN UPGRADE.
WEAK SHORTWAVE TROUGH WILL PASS THROUGH THE TRI-STATE AREA TUESDAY
NIGHT INTO WEDNESDAY. STRONGEST FORCING FOR ASCENT WILL REMAIN
NORTH OF THE FORECAST AREA BUT CAN`T COMPLETELY RULE OUT AN
ISOLATED/SCATTERED STORM. POTENTIAL FOR ISOLATED CONVECTION WILL
CONTINUE EACH AFTERNOON THROUGH THE END OF THE FORECAST PERIOD. TEMPS
WILL BE ONLY SLIGHTLY COOLER WITH HIGHS RANGING FROM THE MID 90S
TO AROUND 105 FROM WEST TO EAST.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1100 AM MDT FRI JUL 20 2012
VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD AT BOTH KGLD AND
KMCK. SOUTHEAST WINDS AROUND 11KT WILL PERSIST THROUGH
TONIGHT...WITH GUSTS THIS AFTERNOON AND EARLY EVENING 15-18KT. LEE
TROUGH STRENGTHENS SOME OVER EASTERN COLORADO...WITH GRADIENT
INCREASING SOME OVER BOTH TERMINALS. RESULT WILL BE WINDS SHIFTING
TO THE SOUTH...WITH GUSTY WINDS AROUND 18KT DEVELOPING AFTER
SUNRISE SATURDAY MORNING.
&&
.CLIMATE...
ISSUED AT 112 PM MDT FRI JUL 20 2012
VERY HOT TEMPERATURES ARE EXPECTED TO CONTINUE THROUGH NEXT
WEEK...WITH SEVERAL LOCATIONS POSSIBLY BREAKING A DAILY
TEMPERATURE RECORD ON SATURDAY AND SUNDAY.
DAILY RECORDS FOR SATURDAY (JUL 21)...
GOODLAND.....105 (2005)
HILL CITY....110 (1934)
BURLINGTON...103 (2005)
MCCOOK.......105 (2005)
YUMA.........109
TRIBUNE......107
COLBY........106
DAILY RECORDS FOR SUNDAY (JUL 22)...
GOODLAND.....105 (1934)
HILL CITY....108 (1934)
BURLINGTON...104 (1990)
MCCOOK.......110 (1931)
YUMA.........109
TRIBUNE......107
COLBY........107
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...HEAT ADVISORY UNTIL 9 PM CDT TUESDAY FOR KSZ002>004-014>016-028-
029-042.
CO...NONE.
NE...HEAT ADVISORY UNTIL 9 PM CDT TUESDAY FOR NEZ080-081.
&&
$$
SHORT TERM...DR
LONG TERM...FOLTZ
AVIATION...DR
AREA FORECAST DISCUSSION
NWS GOODLAND KS
112 PM MDT FRI JUL 20 2012
.SHORT TERM...(THIS AFTERNOON THROUGH SATURDAY)
ISSUED AT 112 PM MDT FRI JUL 20 2012
LATEST WV IMAGERY AND RUC H5 ANALYSIS SHOW LARGE RIDGE ACROSS THE
INTER-MOUNTAIN WEST...CENTERED OVER EASTERN COLORADO. AT THE
SURFACE A WEAK SURFACE TROUGH IS IN PLACE WITH ITS MAIN AXIS ALONG
THE FRONT RANGE. SEVERAL WEAK SURFACE TROUGHS EXTEND EAST TOWARDS
THE KS CO BORDER.
WEAK SURFACE CONVERGENCE ALONG THESE SURFACE TROUGHS AND STEEP LOW
LEVEL LAPSE RATES HAVE LED TO THE DEVELOPMENT OF SHALLOW CUMULUS
EARLY THIS AFTERNOON. LARGE SCALE SUBSIDENCE COMBINED WITH A VERY
STRONG CAP WILL LIMIT UPDRAFT POTENTIAL...SO I HAVE KEPT ANY
THUNDERSTORM MENTION OUT OF FORECAST THROUGH TOMORROW.
WITH DRY CONDITIONS EXPECTED MAIN CONCERN IS NEAR RECORD
TEMPERATURES AND POSSIBLE FIRE WEATHER CONCERNS. WITH GUIDANCE
SHOWING AIRMASS SLIGHTLY ALOFT THAN TODAY...AND WINDS SHIFTING TO
THE SOUTH-SOUTHWEST TEMPERATURES ACROSS MUCH OF THE AREA COULD SEE
TEMPERATURES IN THE 105 TO 110 RANGE. RED FLAG CONDITIONS ARE NOT
CURRENTLY EXPECTED...WITH WINDS AROUND 20 MPH. IF RH VALUES WERE
TO DROP TO 10 PERCENT IN THE WEST THEN WE COULD MEET CRITERIA.
THIS IS NOT EXPECTED TO OCCUR...SO NO FIRE WEATHER HIGHLIGHTS
PLANNED FOR SATURDAY AT THIS POINT.
.LONG TERM...(MONDAY THROUGH THURSDAY)
ISSUED AT 225 AM MDT FRI JUL 20 2012
THE RIDGE WILL CONTINUE OVER THE PLAINS. A FRONT EXTENDING ACROSS
NORTHERN NEBRASKA INTO EASTERN WYOMING WILL SHIFT SOUTH INTO
NORTHWEST KANSAS WEDNESDAY/THURSDAY. UNTIL THEN SUBSIDENCE AND VERY
WARM TEMPERATURES ALOFT WILL INHIBIT THUNDERSTORMS ACROSS THE FA.
THE RIDGE FLATTENS SOME TUESDAY NIGHT AS AN UPPER LOW MOVES ACROSS
SOUTHERN CANADA. THERE WILL BE A SLIGHT CHANCE OF THUNDERSTORMS NEAR
THE FRONT TUESDAY NIGHT. MORE STORMS WILL BE POSSIBLE
WEDNESDAY/THURSDAY.
MAX TEMPERATURES WILL CONTINUE TOPPING OUT IN THE UPPER 90S/LOW 100S
COOLING TO THE MID 90S THURSDAY. MIN TEMPERATURES WILL RANGE FROM
THE UPPER 60S IN EASTERN COLORADO TO THE MID 70S IN THE EASTERN FA.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1100 AM MDT FRI JUL 20 2012
VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD AT BOTH KGLD AND
KMCK. SOUTHEAST WINDS AROUND 11KT WILL PERSIST THROUGH
TONIGHT...WITH GUSTS THIS AFTERNOON AND EARLY EVENING 15-18KT. LEE
TROUGH STRENGTHENS SOME OVER EASTERN COLORADO...WITH GRADIENT
INCREASING SOME OVER BOTH TERMINALS. RESULT WILL BE WINDS SHIFTING
TO THE SOUTH...WITH GUSTY WINDS AROUND 18KT DEVELOPING AFTER
SUNRISE SATURDAY MORNING.
&&
.CLIMATE...
ISSUED AT 112 PM MDT FRI JUL 20 2012
VERY HOT TEMPERATURES ARE EXPECTED TO CONTINUE THROUGH NEXT
WEEK...WITH SEVERAL LOCATIONS POSSIBLY BREAKING DAILY TEMPERATURE
RECORD ON SATURDAY AND SUNDAY.
DAILY RECORDS FOR SATURDAY (JUL 21)...
GOODLAND.....105 (2005)
HILL CITY....110 (1934)
BURLINGTON...103 (2005)
MCCOOK.......105 (2005)
YUMA.........109
TRIBUNE......107
COLBY........106
DAILY RECORDS FOR SUNDAY (JUL 22)...
GOODLAND.....105 (1934)
HILL CITY....108 (1934)
BURLINGTON...104 (1990)
MCCOOK.......110 (1931)
YUMA.........109
TRIBUNE......107
COLBY........107
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...HEAT ADVISORY UNTIL 9 PM CDT SUNDAY FOR KSZ002>004-014>016-028-
029-042.
CO...NONE.
NE...HEAT ADVISORY UNTIL 9 PM CDT SUNDAY FOR NEZ080-081.
&&
$$
SHORT TERM...DR
LONG TERM...FS
AVIATION...DR
CLIMATE...DR
AREA FORECAST DISCUSSION...UPDATED
NWS DULUTH MN
230 PM CDT FRI JUL 20 2012
.MESOSCALE UPDATE...CONCERNING THUNDERSTORM DEVELOPMENT AND SEVERE
WEATHER POTENTIAL THIS AFTERNOON...
AS OF 2 PM THIS AFTERNOON...RATHER COMPLEX SURFACE FRONTAL ZONE
AND ASSOCIATED BOUNDARY LAYER MASS CONVERGENCE AXIS CONTINUE TO
MOVE SOUTHEASTWARD ACROSS NORTHWEST MINNESOTA. MAIN CONVERGENCE
AXIS AND INITIAL WIND SHIFT EXTENDS FROM BETWEEN FARGO AND GRAND
FORKS TO JUST WEST OF INTERNATIONAL FALLS...WITH A NARROW AXIS OF
DRIER AIR WORKING EASTWARD ALONG THE IMMEDIATE WIND SHIFT LINE.
HOWEVER..RICH BOUNDARY LAYER MOISTURE WITH DEWPOINTS IN THE UPPER
60S TO LOWER 70S EXISTS OVER MUCH OF THE DULUTH CWA AHEAD OF THIS
LOCAL DRYING PLUME..AND THERE IS ALSO A NARROW ZONE OF RICH BOUNDARY
LAYER MOISTURE JUST BEHIND THE FRONT OVER FAR NW/NCENT MN WHERE
BOUNDARY LAYER CUMULUS HAS RAPIDLY DEVELOPED OVER THE PAST HOUR OR
SO.
THERE IS STILL A FAIR AMOUNT OF UNCERTAINTY AS TO EXACTLY WHERE AND
WHEN DEEP CONVECTION MIGHT DEVELOP THIS AFTERNOON WITH CONSIDERABLE
SPREAD STILL IN THE SHORT RANGE HI-RESOLUTION GUIDANCE THROUGH THIS
EVENING. LOCAL DLH WRF SUGGESTS SVR STORMS WILL DEVELOP IN THE RED
LAKE TO KINL AREA BETWEEN 3-4 PM AND THEN MAINTAIN FOR SEVERAL HOURS
WHILE MOVING SEWD ACROSS THE CENTRAL SRN PORTIONS OF THE DLH CWA.
HOWEVER..SEVERAL OTHER MODELS SUGGEST NOT MUCH IN THE WAY OF DEEP
CONVECTION AT ALL WITH A MAINLY DRY FRONTAL PASSAGE.
GIVEN THE APPROACHING UPPER LEVEL SPEED MAX AND WEAK WAVE AS
EVIDENCED IN UPPER LEVEL RAP PV OBJECTIVE ANALYSIS FIELDS..AND THE
STRENGTH OF THE INSTABILITY PRESENT IT SEEMS A LITTLE BIT OF A
STRETCH THAT NO STORMS AT ALL WOULD FORM. THE GREATEST RISK OF
STRONG/SVR TSTORM DEVELOPMENT APPEARS TO BE BETWEEN THE WALKER/RED
LAKE/INTERNATIONAL FALLS/VOYAGEURS NATIONAL PARK AREA BETWEEN 3-5
PM..WITH A GENERAL SOUTHEAST MOVEMENT THEREAFTER INTO THE CORRIDOR
FROM BRAINERD/WALKER NEWD TO THE IRON RANGE AND ELY BY EARLY
EVENING.
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
MILLER
AREA FORECAST DISCUSSION
NWS RALEIGH NC
146 PM EDT FRI JUL 20 2012
.SYNOPSIS...
A COLD FRONT APPROACHING FROM THE NORTH WILL STALL OVER THE AREA
THROUGH THE WEEKEND...PROVIDING FOR UNSETTLED WEATHER. AS THE FRONT
BASICALLY DISSIPATES BY EARLY NEXT WEEK...HIGH TEMPERATURES ONCE
AGAIN WILL WARM TO LEVELS ABOVE NORMAL.
&&
.NEAR TERM /TODAY AND TONIGHT/...
AS OF 1005 AM FRIDAY...
THE LATEST SURFACE ANALYSIS SHOWED A WAVY FRONTAL BOUNDARY...WITH
SURFACE WAVES ALONG THE BOUNDARY...EXTENDING MAINLY ALONG AND NEAR
THE OHIO RIVER...THEN SOUTHEAST FROM SOUTHERN OHIO TOWARD DELMARVA.
A SURFACE TROUGH WAS ALSO LOCATED OVER THE FOOTHILLS AND FAR WESTERN
PIEDMONT. WHILE THE SURFACE GRADIENT WAS SLACK OVER CENTRAL NORTH
CAROLINA...AMDAR SOUNDINGS AS WELL AS THE KGSO 12Z SOUNDING SHOWED
SOME WINDS NEAR THE INVERSION AROUND 20KT. ALREADY...THERE HAVE BEEN
A COUPLE OF GUSTS APPROACHING 20KT ON SURFACE OBSERVATIONS...NOTABLY
AT KFAY.
WHILE DIFFICULT TO RESOLVE ON STANDARD WATER VAPOR IMAGERY...EARLY
MORNING VISIBLE IMAGERY WOULD SUGGEST AN MCV MOVING OVER FAR
NORTHEAST TENNESSEE...WHICH ESSENTIALLY ALL OF THE SHORT-TERM
GUIDANCE FORECASTS MOVING EAST OVER OR VERY NEAR CENTRAL NORTH
CAROLINA DURING THE AFTERNOON. THE RUC IS THE STRONGEST AMONG THE
GFS AND NAM...AND WHILE PRECIPITABLE WATER VALUES ARE CURRENTLY AT A
REGIONAL MINIMUM OVER THE WESTERN THIRD OF THE STATE ON THE LATEST
SPC MESOANALYSIS...WITH THE APPROACH OF THE MCV AND EXPECTED SLOW
EASTWARD PROGRESS OF THE SURFACE TROUGH IN RESPONSE...850MB THETA-E
ADVECTION FROM THE SOUTHWEST SHOULD LIMIT OR NULLIFY ANY
PRECIPITABLE WATER REDUCTION THIS AFTERNOON. 850MB DEW POINTS ARE IN
THE TEENS ON THE LATEST UPPER-AIR ANALYSIS AT THAT LEVEL.
MORNING LOW CLOUDS WERE GRADUALLY DIMINISHING ON THE LATEST VISIBLE
IMAGES...AND WHILE 1000-500MB LAPSE RATES ARE NOT FORECAST
PARTICULARLY HIGH THIS AFTERNOON...TO AROUND 6.5C/KM...AND DCAPE IS
FAIRLY LOW...AROUND 200J/KG...THE COMBINATION OF BETTER SYNOPTIC
FORCING...BETTER AVAILABLE LOW-LEVEL WINDS...AND SOME INCREASING
SHEAR LATE ESPECIALLY NORTHWEST...WHERE 0-6KM SHEAR SHOULD INCREASE
TO AROUND 25KT...SHOULD PROVIDE FOR THE POTENTIAL OF SOME
THUNDERSTORMS ORGANIZING ENOUGH TO HAVE A RISK FOR SEVERE WEATHER
WITH DAMAGING WIND THE PRIMARY SEVERE WEATHER THREAT. SREF
PROBABILISTIC FORECAST FOR GREATER THAN 100 CLOUD-TO-GROUND
LIGHTNING STRIKES SUGGESTS A MAXIMUM OVER THE WESTERN PIEDMONT...AND
THIS SEEMS REASONABLE WHERE THE -10C TO -30C CAPE IS A MAXIMUM...TO
AROUND 600J/KG. THE PREVIOUS FORECAST OF SCATTERED TO NUMEROUS
SHOWERS AND THUNDERSTORMS DEVELOPING SEEMS VERY REASONABLE AND
CONTINUED THIS FOR THE AFTERNOON...INCREASING THE RAW NUMBERS ON THE
CHANCES FOR RAIN MAINLY TOWARD THE YADKIN RIVER TO JUST SHY OF
CATEGORICAL BASED ON THE CONSENSUS OF THE ABOVE...PLUS MOS GUIDANCE
AND THE LATEST HRRR WRF OUTPUT. TEMPERATURES IN MOST LOCATIONS...
AFTER A SLOW START IN THEIR RISE DUE TO CLOUDS...SHOULD REACH LOWER
TO MID 90S...POSSIBLY MORE OF A STRUGGLE TO REACH 90 IN THE
IMMEDIATE TRIAD. -DJF
TONIGHT...SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS WILL
EVENTUALLY DECREASE FROM W-E OR NW-SE AFTER MIDNIGHT IN ASSOC/W
CONVECTIVE OVERTURNING AND NOCTURNAL STABILIZATION. HOWEVER...WILL
KEEP AT LEAST 20-30% PRECIP CHANCES IN PLACE THE REMAINDER OF THE
NIGHT GIVEN AN APPROACHING UPPER LEVEL TROUGH IN THE PRESENCE OF A
VERY MOIST AND MARGINALLY UNSTABLE AIRMASS. LOW-LEVEL SHEAR BETWEEN
SUNSET AND MIDNIGHT (01-04Z) THIS EVENING (EAST OF HWY 1) IS PROGGED
TO BE SIMILAR TO THAT ANALYZED BY SPC MESOANALYSIS AT 09Z THIS
MORNING (150 M2/S2 OF 0-1 KM HELICITY AND 20-25 KT OF 0-1 KM BULK
SHEAR OVER CENTRAL/EASTERN NC). HOWEVER...DEEP CONVECTION WOULD HAVE
A DIFFICULT TIME REMAINING SFC-BASED BY THE TIME LOW-LEVEL SHEAR
STRENGTHENS IN CENTRAL NC...AND THE PROBABILITY OF A BRIEF/ISOLD TOR
IS TOO LOW TO MENTION. IF THERE WAS A VERY LOW-END POTENTIAL...IT
WOULD LIKELY BE EAST OF I-95 BETWEEN 01-04Z IN AREAS NOT STABILIZED
BY OUTFLOW AND/OR THE SEABREEZE. WITH A VERY MOIST LOW-LEVEL AIRMASS
IN PLACE...EXPECT LOWS TONIGHT IN THE LOWER 70S...OR 71-74F. -VINCENT
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 145 AM FRIDAY...
PULSE THUNDERSTORMS WILL BRING LOCALLY VERY HEAVY RAIN AND GUSTY
WINDS BOTH SATURDAY AND SUNDAY.
A WEAK SURFACE COLD FRONT IS EXPECTED TO DRIFT SOUTHERLY SOUTH
THROUGH TN/WVA/VA SATURDAY... POSSIBLY REACHING NORTHERN NC LATE
SATURDAY AND SATURDAY NIGHT... BEFORE STALLING OVER OUR REGION INTO
SUNDAY. THE STRONG CONFLUENCE ALONG THIS FRONT WILL COMBINE WITH
STRONG SURFACE HEATING TO PROVIDE MORE THAN ADEQUATE LIFT OF VERY
MOIST AIR IN SUPPORT OF THE DEVELOPMENT OF NUMEROUS THUNDERSTORMS
AGAIN SATURDAY AFTERNOON INTO THE EVENING. AREAL AVERAGE QPF SHOULD
BE ON THE ORDER OF 0.50 TO 1 INCH... WITH SOME LOCALLY VERY HEAVY
AMOUNTS IN EXCESS OF 2 INCHES POSSIBLE DUE TO THE MOISTURE POOLING
AND SLOW STORM MOVEMENT. THIS INFORMATION WILL CONTINUE TO BE
MENTIONED IN THE HAZARDOUS WEATHER OUTLOOK (HWO). SUNDAY SHOULD
AGAIN BE JUST AS CONVECTIVELY ACTIVE WITH THE LOW LEVEL CONFLUENCE
ZONE BECOMING NEARLY STATIONARY OVER THE PIEDMONT. QPF SUNDAY WILL
AGAIN INDICATE 0.50 TO 1 INCH AREAL AVERAGES... WITH LOCALLY 2
INCHES AGAIN POSSIBLE. HOPEFULLY... THE HEAVIER AMOUNTS WILL FALL IN
DIFFERENT LOCATIONS THAN THOSE THAT RECEIVE HEAVY AMOUNTS BOTH
FRIDAY AND SATURDAY. THAT IS NOT ALWAYS THE CASE HOWEVER...
THEREFORE SOME LOCAL AREAS MAY RECEIVE OVER 4 INCHES OF RAIN TOTAL
TODAY THROUGH SUNDAY.
SHEAR IS FORECAST TO CONTINUE TO BE LACKING WHICH OFTEN WILL LEAD TO
THE CONVECTIVE MODE BEING "PULSE"... OR TYPICAL SUMMERTIME STRONG
THUNDERSTORMS. THIS MEANS LESS IN THE WAY OF ORGANIZED SEVERE
STORMS. HOWEVER... EVEN THOUGH "ORGANIZED AND WIDESPREAD" SEVERE
THUNDERSTORMS ARE NOT FORECAST... THERE WILL LIKELY BE BE A RAPID
DEVELOPMENT OF "PULSE" THUNDERSTORMS BOTH SATURDAY AND SUNDAY. SOME
OF THESE MAY BECOME LOCALLY SEVERE WITH DAMAGING WIND GUSTS TO 60
MPH POSSIBLE. WE WILL HIGHLIGHT THIS LOCAL PULSE SEVERE CHANCE AS
WELL IN THE HWO FOR BOTH DAYS. HIGHS SATURDAY ARE FAVORED TO BE IN
THE 86-92 RANGE... N TO S. LOWS SATURDAY NIGHT... 69-73. HIGHS
SUNDAY MAY BE A BIT COOLER (ONLY DUE TO THE FORECAST HIGH DEW POINTS
AND WETTER GROUND BY THEN) 85-90.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 145 AM FRIDAY...
ANOTHER HOT AND HUMID WEEK...WITH A CHANCE OF MAINLY AFTERNOON AND
EVENING THUNDERSTORMS.
STRONG UPPER RIDGING IS FORECAST TO BEGIN TO EXTEND EASTWARD FROM
THE CENTRAL UNITED STATES TO NEAR THE APPALACHIANS BY MID WEEK. THE
BOUNDARY THAT IS FORECAST TO BRING THE THUNDERSTORMS TO OUR REGION
THIS WEEKEND IS FORECAST TO DISSIPATE OVER OUR AREA MONDAY THROUGH
TUESDAY. AS WE LOSE THE INFLUENCE OF THE BOUNDARY (LIFT/MOISTURE
POOLING/CONVERGENCE) WE WILL SEE THE WIDESPREAD STORMS OF THE
WEEKEND BECOME SCATTERED DURING MONDAY AND TUESDAY. A NW FLOW ALOFT
MAY NOT TURN OUT TO BE THAT MUCH DRIER MID TO LATE WEEK AS
DISTURBANCES ALOFT MAY TRIGGER AT LEAST SCATTERED DIURNAL STORMS ALL
WEEK. WE WILL MAINTAIN POPS OF AT LEAST CLIMATOLOGY FOR LATE JULY
(35 PERCENT OR SO) MOST OF THE WEEK.
THE HEAT WILL ALSO BEGIN TO RETURN WITH LESS IN THE WAY OF CLOUDS/
STORMS DURING THE PM HOURS. THEREFORE...HIGHS ARE EXPECTED TO BE IN
THE UPPER 80S TO LOWER 90S MONDAY...90-95 TUESDAY... THEN MOSTLY MID
90S BY THURSDAY. IT WILL CONTINUE VERY MUGGY WITH DEW POINTS IN THE
70S. LOWS WILL ALSO BE IN THE 70S.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
AS OF 145 PM FRIDAY...
VFR CONDITIONS WILL BE THE RULE OUTSIDE OF SHOWERS AND THUNDERSTORMS
THROUGH THIS EVENING. SHOWERS AND THUNDERSTORMS WILL PRODUCE LOCALLY
GUSTY WINDS...NOTE THE GUST TO 36KT AT KPOB AT 1718Z. OVERNIGHT...
IT IS DIFFICULT TO ASSESS THE POTENTIAL FOR LOW CLOUDS. THE HIGHER
WINDS JUST OFF OF THE SURFACE WILL BE TOWARD KFAY AND KRWI LATE
TONIGHT...WHILE THE SREF MODEL HAS ITS HIGHEST PROBABILITIES MOSTLY
FROM KGSO AND KRDU SOUTHWEST...AND HIGHER THAN IT INITIALIZED THIS
MORNING WHEN MVFR AND LOCALLY IFR CEILINGS OCCURRED ACROSS CENTRAL
NORTH CAROLINA. CONFIDENCE IS FAIRLY HIGH THAT THERE WILL BE AREAS
OF MVFR CEILINGS IN CENTRAL NORTH CAROLINA...BUT THE LOCATION OF THE
LOWER CEILINGS IS MORE UNCERTAIN. FOR THE 18Z VALID TAF...LEANED
TOWARD THE SREF OUTPUT WITH THE TEMPORARY CONDITIONS OF IFR CLOUDS
TOWARD KGSO AND KRDU...AND ONLY LOW MVFR CEILINGS AT KFAY AND KRWI
LATE TONIGHT AND EARLY SATURDAY AFTER SUNRISE.
BEYOND THE 18Z VALID TAF PERIOD...ANTICIPATE SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS DEVELOPING IN A MOIST AIR MASS AGAIN BY LATE
SATURDAY MORNING...BECOMING MORE NUMEROUS DURING THE AFTERNOON AND
CONTINUING INTO SATURDAY EVENING. REMAINING SHOWERS SHOULD BECOME
MUCH MORE ISOLATED OR DIMINISH LATE SATURDAY NIGHT. SCATTERED
SHOWERS AND THUNDERSTORMS OCCUR AGAIN SUNDAY...THEN ANY SHOWERS AND
THUNDERSTORMS SHOULD TEND TO BECOME MORE ISOLATED EARLY NEXT WEEK AS
THE COLD FRONT MOVING SOUTH CURRENTLY FROM VIRGINIA STALLS AND
DISSIPATES. LATE NIGHT AND EARLY MORNING LOW CLOUDS ARE ALSO
POSSIBLE...WITH THE LATEST GUIDANCE SUGGESTING A BETTER POTENTIAL
LATE SATURDAY NIGHT INTO EARLY SUNDAY MORNING.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...SEC/DJF
NEAR TERM...DJF/VINCENT
SHORT TERM...BADGETT
LONG TERM...BADGETT
AVIATION...DJF
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
435 PM EDT FRI JUL 20 2012
.SYNOPSIS...
HIGH PRESSURE WILL MOVE ACROSS THE AREA THROUGH THE WEEKEND.
A COLD FRONT WILL APPROACH FROM THE NORTH BY TUESDAY.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
LINE OF CONVECTION AHEAD OF A COLD FRONT WILL CONTINUE TO PUSH
SOUTH OUT OF THE REGION LATE THIS AFTERNOON INTO THE EARLY
EVENING. CONSIDERABLE LOW CLOUD COVER WILL START TO CLEAR FROM
THE NORTHWEST DURING THIS TIME FRAME. LATEST RAP RUNS SUGGEST THAT
CLEARING SHOULD ACCELERATE ACROSS A GOOD PART OF THE AREA LATER IN
THE EVENING. BUT STILL SOME QUESTION WHETHER/WHEN CLOUDS WILL
DIMINISH IN SOUTHEASTERN ZONES. NOT OUT OF THE QUESTION THAT THERE
COULD BE SOME FOG DEVELOPMENT WHERE SKIES CLEAR ALTHOUGH DRYING
LOW LEVELS SHOULD OFFSET THAT POTENTIAL AT LEAST SOMEWHAT.
FORECAST LOWS ARE SLIGHTLY ABOVE MOS CONSENSUS.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
HIGH PRESSURE WILL BUILD INTO THE REGION TOMORROW AND MOVE OFF TO
THE SOUTHEAST ON SUNDAY. THIS WILL BRING A DRIER AIR MASS ACROSS
THE REGION. BUT RETURN FLOW ON THE BACK SIDE OF THE HIGH WILL
SLOWLY INCREASE DEW POINTS ONCE AGAIN. A SHORT WAVE WILL MOVE
SOUTHEAST ACROSS THE REGION SATURDAY NIGHT BUT THIS SHOULD ONLY
BRING MID AND HIGH CLOUDS. GUIDANCE IS SUGGESTING THAT A LOW
LEVEL JET WILL PUSH INTO THE LOWER GREAT LAKES SUNDAY NIGHT WHICH
COULD RESULT IN SOME SHOWERS AND THUNDERSTORMS DEVELOPING NORTH OF
THE AREA LATE. KEPT POPS LOW AT THIS POINT BUT WILL HAVE TO
CONTINUE TO WATCH THIS POTENTIAL.
ANY COOLING WITH THIS HIGH WILL BE BRIEF AS UPPER HEIGHTS REMAIN
FAIRLY HIGH WITH THE PERSISTENT RIDGE JUST WEST OF THE REGION.
HAVE FORECAST HIGHS NEAR OR ABOVE WARMER NAM MOS GUIDANCE BUT WENT
WITH MORE OF A BLEND DURING THE NIGHT PERIODS. HOWEVER IF CLOUDS
ARE MORE EXTENSIVE THAN FORECAST...LOWS MAY END UP BEING SEVERAL
DEGREES WARMER.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
MODEL AGREEMENT FOR THE EXTENDED PERIOD REMAINS IN FAIR SHAPE...IN
TERMS OF THE LARGE SCALE FEATURES. GFS ENSEMBLE MEANS CONTINUE TO
SHOW A RELATIVELY SMALL AMOUNT OF SPREAD THROUGH THE END OF NEXT
WEEK. THE OVERALL PATTERN WILL BEGIN WITH THE CONTINUED DOMINANCE OF
A BROAD CENTRAL US RIDGE...WHICH LOSES ITS INFLUENCE OVER THE
EASTERN US AS TROUGHING OVER NEW ENGLAND LEADS TO GRADUAL (AND WEAK)
HEIGHT FALLS IN THE OHIO VALLEY AS THE WEEK PROGRESSES.
THE TRANSITION INTO A NW FLOW REGIME OVER THE OHIO VALLEY WILL LEAD
TO INCREASED CHANCES OF PRECIPITATION AT TIMES DURING THE WEEK.
PREVIOUS GFS/ECMWF MODEL RUNS HAVE NOT BEEN CONSISTENT ON THE
LOCATION OF THE FORCING OR TIMING OF THE BEST PRECIPITATION
CHANCES...BUT THE 12Z RUNS TODAY ARE SIMILAR ENOUGH TO PROVIDE SOME
CONFIDENCE IN THE SPECIFICS OF THE FORECAST. THE HIGHEST MAGNITUDE
OF HEIGHT FALLS WILL OCCUR ON TUESDAY...WITH A WEAK SURFACE FRONT
ALSO MOVING SOUTH INTO THE REGION. POPS HAVE BEEN INCREASED TO THE
30-40 RANGE FOR TUESDAY AFTERNOON. SOME DEGREE OF PRECIPITATION
CHANCES (THOUGH LESS ORGANIZED) WILL CONTINUE THROUGH THE REST OF
THE WEEK...AS THE NEAR-SURFACE BOUNDARY MOVES JUST ENOUGH TO THE
NORTHEAST TO KEEP THE CWA MORE FIRMLY INTO THE SOUTHERN AIR MASS
(WITH GREATER MOISTURE).
THE OVERALL CHANGES TO THE AIR MASS DURING THE EXTENDED WILL BE
SMALL...SO THE TEMPERATURE FORECAST WILL REMAIN MOSTLY UNCHANGED.
WHILE THE OVERALL TREND WILL BE FOR LITTLE CHANGE FROM ONE DAY TO TH
NEXT (WITH MAX TEMPS IN THE LOWER 90S)...WHAT ENDS UP HAPPENING FROM
DAY TO DAY WILL ALMOST CERTAINLY BE INFLUENCED BY CONVECTION OR
LEFTOVER CLOUDS. MONDAY DOES APPEAR TO BE THE WARMEST DAY OF THE
WEEK AT THIS TIME...WITH ONLY VERY LOW CHANCES OF RAIN AND WITH THE
RIDGE STILL HAVING THE GREATEST INFLUENCE.
&&
.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
LINE OF CONVECTION HAS DEVELOPED ALONG A COLD FRONT RUNNING FROM
NR CVG/LUK-HOC-RZT. THIS PUTS THE FRONT THROUGH THE TAFS. EXCEPT
FOR A STRAY SHOWER AROUND ILN AT THE VERY BEGINNING OF THE PERIOD
THE TAFS SHOULD BE DRY.
IFR/MVFR CLDS HAVE BEEN STUBBORN TO RISE. CLEARING IS BACK IN NRN
INDIANA...BUT IT APPEARS THAT IS WILL BE SLOW TO REACH THE TAFS.
THINK THAT THE CIGS WILL RISE...BUT WILL STAYING MVFR THIS AFTN.
SCATTERED OUT CLDS AT DAY AROUND 02Z AND CVG/LUK AROUND 04Z. KEPT
CMH/LCK MVFR CIGS THE ENTIRE NIGHT.
SHOULD SEE FOG REDEVELOP OVERNIGHT...ESPECIALLY IN THE W...WHERE
THE CLOUDS SCT OUT. BROUGHT VSBYS DOWN TO 1SM IN THE WEST BETWEEN
08-12Z. IT MIGHT GO LOWER...BUT CONFIDENCE ISNT HIGH ENOUGH TO
PUT IT IN TAFS THAT FAR OUT ATTM.
MVFR CU SHOULD REDEVELOP TOMORROW MORNING AS FOG DISSIPATES...BUT
THEN SHOULD RISE TO VFR BY THE TIME THE TAFS PERIOD ENDS.
OUTLOOK...THUNDERSTORMS POSSIBLE TUESDAY AND WEDNESDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...
LONG TERM...HATZOS
AVIATION...SITES
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
518 PM EDT FRI JUL 20 2012
.SYNOPSIS...
A STATIONARY FRONT WILL REMAIN DRAPED ACROSS SOUTH CENTRAL
PENNSYLVANIA INTO THE NIGHT. A WEAK RIDGE OF HIGH PRESSURE WILL
BUILD SOUTH ACROSS THE AREA SUNDAY AND MONDAY. TEMPERATURES FOR
MUCH OF NEXT WEEK WILL RETURN TO NEAR...OR SLIGHTLY ABOVE NORMAL.
&&
.NEAR TERM /UNTIL 11 PM THIS EVENING/...
TSRA HAVE FORMED OVER SWRN PA AND ARE MOVING INTO THE LAURELS.
THIS AREA HAS BEEN PINPOINTED BY THE NAM AND RUC FOR THE PAST FEW
RUNS TO RECEIVE THE HEAVIEST RAINFALL OVER THE NEXT 6-9 HOURS.
BEST LLVL CONVERGENCE EXISTS THERE WITH FRONT INCHING SOUTHWARD.
SLIM BREAKS IN THE CLOUDS OVER SWRN PA HAVE ALLOW THE STABILITY TO
DROP AND CAPES TO CLIMB THE NAM HAS BEEN HANDLING THIS SITUATION
WELL WITH THE 06 AND 12Z RUNS. SINCE THEY HAVE HAD SIMILAR 1 TO
1.5 INCH AMOUNTS OF RAIN OVER THE PAST 36 HRS IN THE
LAURELS...HAVE EXPANDED THE FFA WESTWARD. CANCELLED THE FFA OVER
THE SERN COS - STABILITY IS HIGHER IN THE SE...BUT 0.5 TO 1 INCH
AMOUNTS ARE STILL POSSIBLE THERE THROUGH SUNSET. THESE AMOUNTS
SHOULD NOT BE ENOUGH TO CAUSE FLASH FLOODING IN THE SE. THE
STORMS IN THE SWRN COS WILL MOST LIKELY EXPAND AND SHOULD DROP
SLOWLY TO THE E/SE THIS EVENING...TAPERING OFF BY MIDNIGHT.
&&
.SHORT TERM /11 PM THIS EVENING THROUGH 6 PM SATURDAY/...
LOW LEVEL FLOW REMAINS UPSLOPE INTO THE CENTRAL AND WESTERN
MOUNTAINS FOR THE ENTIRE NIGHT AND INTO SAT MORNING. THUS...THE
CLOUDS WILL MOST LIKELY LOWER AS THE LITTLE MIXING IN PLACE THIS
AFTN/EVENING GOES AWAY. EXPECT SOME DRIZZLE OR EVEN LIGHT SHOWERS
TO LINGER THROUGH THE NIGHT. COVERAGE AND INTENSITY ARE EXPECTED
TO BE ISOLD/SCT AND VERY LIGHT...SO WILL JUST CALL FOR AREAS OF
DZ AND FG AT MOST PLACES...ESP THE HILL TOPS. MINS WILL HOLD
WITHIN 5 DEGS OF 60F. MINOR LLVL RIDGING BUILDING DOWN FROM NY
STATE WILL ASSIST THE DAYTIME MIXING ON SAT IN EATING AWAY AT THE
STRATUS FROM THE OUTSIDE INWARD. WILL KEEP IT VERY CLOUDY IN THE
LAURELS AND CENTRAL MTS THROUGH THE ENTIRE DAY WITH HIGH RH KEPT
IN BY THE MDLS FOR THE LAYER BELOW 10KFT IN THE AM - AND MIXING
FROM BELOW HELPING TO LIFT THE LAYER TO A BASE OF 4-5KFT BY THE
END OF THE DAY. WILL MENTION DZ OR SCT SHRA IN THE MORNING FOR
THE CENTRAL MTS...AND FOR MOST OF THE DAY IN THE LAURELS.
ELSEWHERE...THE SKIES SHOULD SHOW SIGNIFICANT BREAKS IN THE AFTN.
BUT RIDGING WILL KEEP IT STABLE ENOUGH TO PRECLUDE MENTIONS OF
SHOWERS IN THE AFTN. TEMPS WILL CREEP CLOSER TO NORMAL MAXES ON
SAT WITH THE SLOWLY ERODING/THINNING CLOUDS. WILL MAKE IT MILDER
IN THE EAST WHERE CLOUDS HAVE THE BEST CHANCE OF MELTING AWAY.
&&
.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
THE LONG TERM BEGINS WITH REGION UNDER UPPER-LEVEL NORTHWESTERLY
FLOW...WITH WEAK EMBEDDED DISTURBANCES. ALTHOUGH MUCH OF SUNDAY
AND MONDAY WILL BE PARTLY TO MOSTLY SUNNY AND DRY...THERE IS A
CHANCE FOR A MAINLY AFTN/EVE SHOWER OR THUNDERSTORM EACH DAY.
A SHARPER UPPER-LEVEL TROUGH WILL DIG INTO THE NORTHEASTERN
UNITED STATES ON TUESDAY...PUSHING A COLD FRONT ACROSS THE
COMMONWEALTH. THIS FRONT WILL BE ACCOMPANIED BY A CHC OF
SHRA/TSRA...ALTHOUGH EVEN TUES SHOULD FEATURE AT LEAST PARTIAL
SUNSHINE.
WEDNESDAY SHOULD BE A BIT COOLER AND DRIER AS THE FRONT SAGS JUST
TO OUR SOUTH AND STALLS. THE MODELS ARE HINTING THAT THE FRONT
WILL LIFT BACK NORTHWARD INTO THE REGION LATE IN THE
WEEK...BRINGING A RETURN OF UNSETTLED WEATHER.
TEMPERATURES WILL RISE TO ABOVE-NORMAL LEVELS MONDAY AND TUESDAY
PRIOR TO THE FRONTAL PASSAGE...BEFORE RETURNING CLOSER TO NORMAL
FOR THE MIDDLE TO LATTER PART OF THE WEEK.
&&
.AVIATION /21Z FRIDAY THROUGH WEDNESDAY/...
SLOW MOVING LOW PRES SYSTEM PASSING SOUTH OF PA TONIGHT WILL BRING
LOW CIGS AND OCNL RAIN/DRIZZLE TO CENTRAL PA THIS EVENING. A RIDGE OF
HIGH PRES OVR THE GRT LKS WILL PUSH SOUTHEAST TONIGHT...BRINGING
IMPROVING CONDS ACROSS THE SUSQ VALLEY INCLUDING IPT AND POSSIBLY
MDT/LNS LATE TONIGHT. HOWEVER...MOIST EASTERLY FLOW ASCENDING THE
HIGHER TERRAIN OF CENTRAL PA WILL LIKELY CAUSE IFR CIGS TO
PERSIST FROM BFD SOUTHWARD THRU UNV...AOO AND JST.
SLOW IMPROVEMENT TO GENERALLY MVFR CONDITIONS OVR THE CENTRAL MTNS SAT
AND VFR SUSQ VALLEY. CONTINUED IMPROVEMENT IS POSSIBLE SAT
NIGHT...BUT KJST MAY STAY IFR/MVFR INTO SUNDAY MORNING.
OUTLOOK...
MON-WED...MAINLY VFR...SCT PM TSTMS POSSIBLE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL 11 PM EDT THIS EVENING FOR PAZ024>026-
033>036.
&&
$$
SYNOPSIS...LAMBERT
NEAR TERM...DANGELO
SHORT TERM...DANGELO
LONG TERM...EVANEGO
AVIATION...DANGELO/FITZGERALD
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
323 PM EDT FRI JUL 20 2012
.SYNOPSIS...
A STATIONARY FRONT WILL REMAIN DRAPED ACROSS SOUTH CENTRAL
PENNSYLVANIA INTO THE NIGHT. A WEAK RIDGE OF HIGH PRESSURE WILL
BUILD SOUTH ACROSS THE AREA SUNDAY AND MONDAY. TEMPERATURES FOR
MUCH OF NEXT WEEK WILL RETURN TO NEAR...OR SLIGHTLY ABOVE NORMAL.
&&
.NEAR TERM /UNTIL 11 PM THIS EVENING/...
TSRA HAVE FORMED OVER SWRN PA AND ARE MOVING INTO THE LAURELS.
THIS AREA HAS BEEN PINPOINTED BY THE NAM AND RUC FOR THE PAST FEW
RUNS TO RECEIVE THE HEAVIEST RAINFALL OVER THE NEXT 6-9 HOURS.
BEST LLVL CONVERGENCE EXISTS THERE WITH FRONT INCHING SOUTHWARD.
SLIM BREAKS IN THE CLOUDS OVER SWRN PA HAVE ALLOW THE STABILITY TO
DROP AND CAPES TO CLIMB THE NAM HAS BEEN HANDLING THIS SITUATION
WELL WITH THE 06 AND 12Z RUNS. SINCE THEY HAVE HAD SIMILAR 1 TO
1.5 INCH AMOUNTS OF RAIN OVER THE PAST 36 HRS IN THE
LAURELS...HAVE EXPANDED THE FFA WESTWARD. CANCELLED THE FFA OVER
THE SERN COS - STABILITY IS HIGHER IN THE SE...BUT 0.5 TO 1 INCH
AMOUNTS ARE STILL POSSIBLE THERE THROUGH SUNSET. THESE AMOUNTS
SHOULD NOT BE ENOUGH TO CAUSE FLASH FLOODING IN THE SE. THE
STORMS IN THE SWRN COS WILL MOST LIKELY EXPAND AND SHOULD DROP
SLOWLY TO THE E/SE THIS EVENING...TAPERING OFF BY MIDNIGHT.
&&
.SHORT TERM /11 PM THIS EVENING THROUGH 6 PM SATURDAY/...
LOW LEVEL FLOW REMAINS UPSLOPE INTO THE CENTRAL AND WESTERN
MOUNTAINS FOR THE ENTIRE NIGHT AND INTO SAT MORNING. THUS...THE
CLOUDS WILL MOST LIKELY LOWER AS THE LITTLE MIXING IN PLACE THIS
AFTN/EVENING GOES AWAY. EXPECT SOME DRIZZLE OR EVEN LIGHT SHOWERS
TO LINGER THROUGH THE NIGHT. COVERAGE AND INTENSITY ARE EXPECTED
TO BE ISOLD/SCT AND VERY LIGHT...SO WILL JUST CALL FOR AREAS OF
DZ AND FG AT MOST PLACES...ESP THE HILL TOPS. MINS WILL HOLD
WITHIN 5 DEGS OF 60F. MINOR LLVL RIDGING BUILDING DOWN FROM NY
STATE WILL ASSIST THE DAYTIME MIXING ON SAT IN EATING AWAY AT THE
STRATUS FROM THE OUTSIDE INWARD. WILL KEEP IT VERY CLOUDY IN THE
LAURELS AND CENTRAL MTS THROUGH THE ENTIRE DAY WITH HIGH RH KEPT
IN BY THE MDLS FOR THE LAYER BELOW 10KFT IN THE AM - AND MIXING
FROM BELOW HELPING TO LIFT THE LAYER TO A BASE OF 4-5KFT BY THE
END OF THE DAY. WILL MENTION DZ OR SCT SHRA IN THE MORNING FOR
THE CENTRAL MTS...AND FOR MOST OF THE DAY IN THE LAURELS.
ELSEWHERE...THE SKIES SHOULD SHOW SIGNIFICANT BREAKS IN THE AFTN.
BUT RIDGING WILL KEEP IT STABLE ENOUGH TO PRECLUDE MENTIONS OF
SHOWERS IN THE AFTN. TEMPS WILL CREEP CLOSER TO NORMAL MAXES ON
SAT WITH THE SLOWLY ERODING/THINNING CLOUDS. WILL MAKE IT MILDER
IN THE EAST WHERE CLOUDS HAVE THE BEST CHANCE OF MELTING AWAY.
&&
.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
THE LONG TERM BEGINS WITH REGION UNDER UPPER-LEVEL NORTHWESTERLY
FLOW...WITH WEAK EMBEDDED DISTURBANCES. ALTHOUGH MUCH OF SUNDAY
AND MONDAY WILL BE PARTLY TO MOSTLY SUNNY AND DRY...THERE IS A
CHANCE FOR A MAINLY AFTN/EVE SHOWER OR THUNDERSTORM EACH DAY.
A SHARPER UPPER-LEVEL TROUGH WILL DIG INTO THE NORTHEASTERN
UNITED STATES ON TUESDAY...PUSHING A COLD FRONT ACROSS THE
COMMONWEALTH. THIS FRONT WILL BE ACCOMPANIED BY A CHC OF
SHRA/TSRA...ALTHOUGH EVEN TUES SHOULD FEATURE AT LEAST PARTIAL
SUNSHINE.
WEDNESDAY SHOULD BE A BIT COOLER AND DRIER AS THE FRONT SAGS JUST
TO OUR SOUTH AND STALLS. THE MODELS ARE HINTING THAT THE FRONT
WILL LIFT BACK NORTHWARD INTO THE REGION LATE IN THE
WEEK...BRINGING A RETURN OF UNSETTLED WEATHER.
TEMPERATURES WILL RISE TO ABOVE-NORMAL LEVELS MONDAY AND TUESDAY
PRIOR TO THE FRONTAL PASSAGE...BEFORE RETURNING CLOSER TO NORMAL
FOR THE MIDDLE TO LATTER PART OF THE WEEK.
&&
.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
FRONTAL SYSTEM ACROSS CENTRAL PA WILL CONTINUE TO SAG SLOWLY
SOUTHWARD THIS EVENING. CONVECTION/THUNDER CURRENTLY OVER THE SW
WILL AFFECT KJST/KAOO THROUGH 02Z/03Z...BUT DIMINISH WITH LOSS OF
HEATING AS WELL AS THE SLOW SAG OF THE FRONT. ELSEWHERE...ONLY
ISOLD/SCT SHRA ARE EXPECTED AS A SHORT WAVE TROUGH SLIDES ACROSS
THE NRN TIER AND WEAK CONVERGENCE/UPSLOPE EXISTS IN THE LLVLS.
THE ENTIRE AREA WILL BE STUCK IN MAINLY IFR OR LOW-END MVFR CLOUDS
AND SCT SHRA OR DZ THROUGH THE WHOLE NIGHT. EXPECT LITTLE CHANGE
IN THE CIGS AND VSBYS TONIGHT...WITH SLIGHT IMPROVEMENT TO
GENERALLY MVFR CONDITIONS IN THE WEST SAT AND VFR EAST. CONTINUED
IMPROVEMENT IS POSSIBLE SAT NIGHT...BUT KJST MAY STAY IFR/MVFR
INTO SUNDAY MORNING.
OUTLOOK...
MON-WED...MAINLY VFR...SCT PM TSTMS POSSIBLE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL 11 PM EDT THIS EVENING FOR PAZ024>026-
033>036.
&&
$$
SYNOPSIS...LAMBERT
NEAR TERM...DANGELO
SHORT TERM...DANGELO
LONG TERM...EVANEGO
AVIATION...DANGELO
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
249 PM EDT FRI JUL 20 2012
.SYNOPSIS...
A STATIONARY FRONT WILL REMAIN DRAPED ACROSS SOUTH CENTRAL
PENNSYLVANIA INTO THE NIGHT. A WEAK RIDGE OF HIGH PRESSURE WILL
BUILD SOUTH ACROSS THE AREA SUNDAY AND MONDAY. TEMPERATURES FOR
MUCH OF NEXT WEEK WILL RETURN TO NEAR...OR SLIGHTLY ABOVE NORMAL.
&&
.NEAR TERM /UNTIL 11 PM THIS EVENING/...
TSRA HAVE FORMED OVER SWRN PA AND ARE MOVING INTO THE LAURELS.
THIS AREA HAS BEEN PINPOINTED BY THE NAM AND RUC FOR THE PAST FEW
RUNS TO RECEIVE THE HEAVIEST RAINFALL OVER THE NEXT 6-9 HOURS.
BEST LLVL CONVERGENCE EXISTS THERE WITH FRONT INCHING SOUTHWARD.
SLIM BREAKS IN THE CLOUDS OVER SWRN PA HAVE ALLOW THE STABILITY TO
DROP AND CAPES TO CLIMB THE NAM HAS BEEN HANDLING THIS SITUATION
WELL WITH THE 06 AND 12Z RUNS. SINCE THEY HAVE HAD SIMILAR 1 TO
1.5 INCH AMOUNTS OF RAIN OVER THE PAST 36 HRS IN THE
LAURELS...HAVE EXPANDED THE FFA WESTWARD. CANCELLED THE FFA OVER
THE SERN COS - STABILITY IS HIGHER IN THE SE...BUT 0.5 TO 1 INCH
AMOUNTS ARE STILL POSSIBLE THERE THROUGH SUNSET. THESE AMOUNTS
SHOULD NOT BE ENOUGH TO CAUSE FLASH FLOODING IN THE SE. THE
STORMS IN THE SWRN COS WILL MOST LIKELY EXPAND AND SHOULD DROP
SLOWLY TO THE E/SE THIS EVENING...TAPERING OFF BY MIDNIGHT.
&&
.SHORT TERM /11 PM THIS EVENING THROUGH 6 PM SATURDAY/...
LOW LEVEL FLOW REMAINS UPSLOPE INTO THE CENTRAL AND WESTERN
MOUNTAINS FOR THE ENTIRE NIGHT AND INTO SAT MORNING. THUS...THE
CLOUDS WILL MOST LIKELY LOWER AS THE LITTLE MIXING IN PLACE THIS
AFTN/EVENING GOES AWAY. EXPECT SOME DRIZZLE OR EVEN LIGHT SHOWERS
TO LINGER THROUGH THE NIGHT. COVERAGE AND INTENSITY ARE EXPECTED
TO BE ISOLD/SCT AND VERY LIGHT...SO WILL JUST CALL FOR AREAS OF
DZ AND FG AT MOST PLACES...ESP THE HILL TOPS. MINS WILL HOLD
WITHIN 5 DEGS OF 60F. MINOR LLVL RIDGING BUILDING DOWN FROM NY
STATE WILL ASSIST THE DAYTIME MIXING ON SAT IN EATING AWAY AT THE
STRATUS FROM THE OUTSIDE INWARD. WILL KEEP IT VERY CLOUDY IN THE
LAURELS AND CENTRAL MTS THROUGH THE ENTIRE DAY WITH HIGH RH KEPT
IN BY THE MDLS FOR THE LAYER BELOW 10KFT IN THE AM - AND MIXING
FROM BELOW HELPING TO LIFT THE LAYER TO A BASE OF 4-5KFT BY THE
END OF THE DAY. WILL MENTION DZ OR SCT SHRA IN THE MORNING FOR
THE CENTRAL MTS...AND FOR MOST OF THE DAY IN THE LAURELS.
ELSEWHERE...THE SKIES SHOULD SHOW SIGNIFICANT BREAKS IN THE AFTN.
BUT RIDGING WILL KEEP IT STABLE ENOUGH TO PRECLUDE MENTIONS OF
SHOWERS IN THE AFTN. TEMPS WILL CREEP CLOSER TO NORMAL MAXES ON
SAT WITH THE SLOWLY ERODING/THINNING CLOUDS. WILL MAKE IT MILDER
IN THE EAST WHERE CLOUDS HAVE THE BEST CHANCE OF MELTING AWAY.
&&
.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
POSITIVE TILT...SFC AND UPPER LEVEL RIDGE WILL NOSE INTO THE REGION
FROM THE WEST SATURDAY NIGHT AND SUNDAY BRINGING PARTIAL
CLEARING...LIGHT WINDS...AND DRY WEATHER.
HIGH TEMPS SUNDAY WILL REBOUND BACK TO NEAR OR JUST SLIGHTLY BELOW
NORMAL. WILL STAY WITH CONTINUITY AND INCLUDE JUST A FEW ISOLATED
SHRA/TSRA AFTER 18Z SUNDAY. HOWEVER...COVERAGE SHOULD BE QUITE
SPARSE AS MID LEVEL LAPSE RATES WILL BE AOB 6C/KM.
THE SERN CANADA AND NE U.S. UPPER TROUGH AMPLIFIES THROUGH THE
MIDWEEK PERIOD. SEVERAL FAST MOVING...ALBEIT RATHER FLAT SHORTWAVES
WILL RACE SOUTHEAST /WITH SOME OBVIOUS TIMING UNCERTAINTY/ AND
TRIGGER SOME MAINLY AFTERNOON/EARLY EVENING SCTD SHOWERS AND TSRA
MONDAY AND TUESDAY.
HEIGHTS BEGIN TO RISE WEDNESDAY ACCOMPANIED BY AN AREA OF HIGH
PRESSURE AT THE SFC DRIFTING OVERHEAD. KEPT IT DRY WITH POPS ONLY
AROUND 10 PERCENT WEDNESDAY. WARMER AIR WILL PUSH EAST INTO THE
REGION AT THE SFC AND ALOFT LATER IN THE WEEK BRINGING A CHANCE FOR
A FEW SHOWERS AND ISOLATED TO SCATTERED TSRA.
TEMPS FOR MUCH OF NEXT WEEK SHOULD BE NEAR TO SLIGHTLY ABOVE NORMAL
WITH MODERATE DEWPOINTS GENERALLY IN THE U50S NORTH...TO MID 60S IN
THE SOUTH.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
FRONTAL SYSTEM ACROSS CENTRAL PA WILL CONTINUE TO SAG SLOWLY
SOUTHWARD THIS EVENING. CONVECTION/THUNDER CURRENTLY OVER THE SW
WILL AFFECT KJST/KAOO THROUGH 02Z/03Z...BUT DIMINISH WITH LOSS OF
HEATING AS WELL AS THE SLOW SAG OF THE FRONT. ELSEWHERE...ONLY
ISOLD/SCT SHRA ARE EXPECTED AS A SHORT WAVE TROUGH SLIDES ACROSS
THE NRN TIER AND WEAK CONVERGENCE/UPSLOPE EXISTS IN THE LLVLS.
THE ENTIRE AREA WILL BE STUCK IN MAINLY IFR OR LOW-END MVFR CLOUDS
AND SCT SHRA OR DZ THROUGH THE WHOLE NIGHT. EXPECT LITTLE CHANGE
IN THE CIGS AND VSBYS TONIGHT...WITH SLIGHT IMPROVEMENT TO
GENERALLY MVFR CONDITIONS IN THE WEST SAT AND VFR EAST. CONTINUED
IMPROVEMENT IS POSSIBLE SAT NIGHT...BUT KJST MAY STAY IFR/MVFR
INTO SUNDAY MORNING.
OUTLOOK...
MON-WED...MAINLY VFR...SCT PM TSTMS POSSIBLE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL 11 PM EDT THIS EVENING FOR PAZ024>026-
033>036.
&&
$$
SYNOPSIS...LAMBERT
NEAR TERM...DANGELO
SHORT TERM...DANGELO
LONG TERM...LAMBERT
AVIATION...DANGELO
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
315 PM EDT FRI JUL 20 2012
.SYNOPSIS...
A COLD FRONT WILL APPROACH FROM THE NORTHWEST TODAY AND ARRIVE ON
SATURDAY. THE FRONT IS EXPECTED TO STALL OVER THE AREA THROUGH THE
WEEKEND BEFORE DISSIPATING MONDAY.
&&
.NEAR TERM /THROUGH SATURDAY/...
FOR THE REMAINDER OF THE AFTERNOON... ANTICIPATE THE FOCUS OF
STRONGEST CONVECTIVE STORMS WILL EXTEND FROM UPSTATE SC NORTHEAST
ITNO THE SOUTHERN PIEDMONT OF NC. THAT IS ALIGNED WITH RAP SBCAPE
MAXIMUM OF 3000+ J/KG. EFFECTIVE SHEAR IS HIGH ENOUGH OVER PORTIONS
OF THE MOUNTAINS TO SUGGEST SOME ORGANIZATION TO THE
THUNDERSTORMS... BUT THAT AREA IS WEST OF THE MOST UNSTABLE AIR.
PLUS... THE MID-LEVEL VORTICITY MAXIMUM AND BEST VORTICITY ADVECTION
APPEARS TO BE MOVING OUT OVER THE PIEDMONT AS SHORT WAVE TROUGH
ALOFT TRAVELS EASTWARD. SHEAR EAST OF MOUNTAINS NOT PARTICULARLY
IMPRESSIVE AND DOWNDRAFT CAPE IS ONLY AROUND 500 J/KG... SO PULSE
NATURE OF STORMS LIKELY TO PREDOMINATE WITH POSSIBILITY OF SOME
MULTICELL CLUSTERS GETTING TOGETHER.
OTHWERWISE... MODELS IN PRETTY GOOD AGREEMENT REGARDING EVOLUTION OF
MID AND UPPER LEVEL FEATURES THROUGH DAYTIME SATURDAY. AT 500 MB...
LARGE RIDGE PERSISTS OVER WESTERN U.S. WITH BERMUDA HIGH OVER
ATLANTIC. 500 MB TROUGH EXTENDING DOWN EAST COAST INTO OUR CWA
PERSISTS THROUGH SATURDAY... BUT IT WITHDRAWS SLOWLY TO THE NORTH
LEAVING A SHEAR AXIS BEHIND. SHORT WAVE TROUGH CROSSING CWA THIS
AFTERNOON AND THIS EVENING WILL MAINTAIN SURFACE LOW ON FRONTAL
BOUNDARY ACROSS MID-ATLANTIC REGION. LOW WILL BE OFFSHORE SATURDAY
MORNING AND CONTINUE MOVING EAST THEREAFTER. BERMUDA HIGH BUILDS
SLOWLY WESTWARD AS 500 MB HEIGHTS INCREASE JUST A BIT. THIS WILL MAKE
SOUTHWARD MOVEMENT OF FRONTAL BOUNDARY VERY DIFFICULT TO MAINTAIN.
MOIST SOUTHWEST FLOW AHEAD OF THE FRONT ON WEST SIDE OF BERMUDA HIGH
WORKS IN COMBINATION WITH THE WEAK UPPER-LEVEL TROUGH/SHEAR AXIS TO
CONTINUE A MOIST SOUTHWEST FLOW INTO OUR AREA. FORECASTS FOR
OVERNIGHT AND SATURDAY ACCORDINGLY WILL CARRY POPS FOR SHOWERS AND
THUNDERSTORMS.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
AT 230 PM EDT FRIDAY...AN UPPER TROUGH AXIS WILL REMAIN ALONG THE
EAST COAST FROM SATURDAY NIGHT THROUGH MONDAY...WHILE A RIDGE
REMAINS OVER THE PLAINS. A WEAKENING...STALLED SURFACE FRONT WILL
REMAIN OVER OUR AREA THROUGH MONDAY. ALTHOUGH THERE DOES NOT APPEAR
TO BE MUCH ISENTROPIC UPGLIDE OVER THE BOUNDARY...SHORTWAVES MOVING
INTO THE UPPER TROUGH AND OVER THE VICINITY OF THE FRONT WILL
SUPPORT PRECIPITATION THROUGH THE PERIOD...MAXIMIZED WITH GREATER
INSTABILITY DURING DAYLIGHT HOURS. WITHOUT A STRONG LIFTING
MECHANISM...PRECIPITATION AMOUNTS ARE EXPECTED TO BE MODERATE...BUT
SEVERAL DAYS OF RAIN COULD LEAD TO SOME LOCALIZED HYDROLOGICAL
PROBLEMS WITH TIME. MINIMUM TEMPERATURES WILL BE SLIGHTLY ABOVE
NORMAL...AND MAXIMUM TEMPERATURES NEAR NORMAL.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AS OF 145 PM FRIDAY...THE CWFA WILL BE IN AN AREA BETWEEN RIDGING TO
THE SOUTH AND WEST AND NW TO SE ORIENTED NRN STREAM FLOW TO THE
NORTH. THE FLOW WILL BE CLOSE ENUF THAT WE SHUD SEE SOME EFFECT FROM
A SERIES OF WEAK SHORT WAVES MOVING THRU THE FLOW. AT THE SFC...A
BACK DOOR COLD FRONT WILL APPROACH THE AREA BUT STALL TO OUR NORTH.
A SERIES OF LOW PRESSURE WAVES WILL MOVE WEST ALONG THE FRONT. OVER
OUR CWFA...A LEE TROF AND COPIOUS LOW LEVEL MOISTURE WILL REMAIN IN
PLACE THRU THE PERIOD. THIS SHUD LEAD TO GENERALLY SCT DIURNAL
CONVECTION EACH DAY. LOWS WILL BE NEARLY STEADY AROUND 5 DEGREES
ABOVE NORMAL. HIGHS START OUT NEARLY 5 DEGREES ABOVE NORMAL THEN
FALL A COUPLE OF DEGREES BY THE END OF THE PERIOD.
&&
.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
AT KCLT... SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE IN THE
VICINITY OF THE TERMINAL THROUGH 00Z. THUNDERSTORMS WILL BE CAPABLE
OF STRONG AND GUSTY WIND AND SMALL HAIL. AFTER 02Z... CEILING 4-6 KT
FT LOWERING TO NEAR 2K FT AROUND 12Z. POSSIBILITY EXISTS OF
VISIBILITY NEAR 5 MI IN FOG AROUND SUNRISE. CONSIDERABLE CLOUDINESS
WILL MAKE RADIATIONAL COOLING DIFFICULT... SO VISILITY RESTRICTION
NOT CURRENTLY IN TAF DUE TO UNCERTAINTY. EXCEPT NEAR
THUNDERSTORMS... SURFACE WIND WILL BE SOUTHWEST LESS THAN 10 KT.
REMAINDER TERMINALS... 4-6K FT BROKEN TO OVERCAST. VISIBILITY
UNRESTRICTED EXPECT VICINITY SCATTERED THUNDERSTORMS... MOST
NUMEROUS NEAR KAND... KGMU... AND KGSP. AFT 02Z... SHOWERS AND
THUNDERSTORMS BECOME MORE WIDELY SCATTERED. TOWARD SUNRISE... SOME
LOWER CEILING 2-4 KT FT AND POSSIBILITY OF VISIBILITY RESTRICTION IN
FOG... ESPECIALLY VICINITY KAVL.
OUTLOOK...AS A COLD FRONT STALLS OVER THE AREA...SCATTERED TO
NUMEROUS CONVECTIVE STORMS AND ASSOCIATED RESTRICTIONS WILL PERSIST
THROUGH THE WEEKEND. LATE NIGHT/MORNING FOG AND LOW STRATUS
PROBABILITIES WILL ALSO REMAIN FAIRLY HIGH...ESPECIALLY IN THE MTN
VALLEYS. THUNDERSTORMS WILL BECOME LESS NUMEROUS AS BERMUDA HIGH
BUILDS INTO THE REGION DURING THE FIRST PART OF THE WEEK.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...JAT
NEAR TERM...LGL
SHORT TERM...JAT
LONG TERM...RWH
AVIATION...LGL
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
151 PM EDT FRI JUL 20 2012
.SYNOPSIS...
A COLD FRONT WILL APPROACH FROM THE NORTHWEST TODAY AND ARRIVE ON
SATURDAY. THE FRONT IS EXPECTED TO STALL OVER THE AREA THROUGH THE
WEEKEND BEFORE DISSIPATING MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AT 130 PM EDT... CONVECTIVE STORMS ARE DEVELOPING RAPIDLY ACROSS
UPSTATE SOUTH CAROLINA INTO THE SOUTHERN PIEDMONT OF NORTH CAROLINA.
EXPECT CONVECTIVE WEATHER TO BE PRIMARY FEATURE THIS AFTERNOON. RAP
CAPES DISPLAY AN AXIS OF 3000 J/KG EXTENDING FROM SOUTH OF KGSP TO
VICINITY KCLT.
PREVIOUS DISCUSSION...
AT 1030 AM EDT... MORNING DATA CONTINUE TO INDICATE POTENTIAL FOR
THUNDERSTORMS DURING THE AFTERNOON AND EVENING... BUT CLOUDINESS
FROM OVERNIGHT MCS TO OUR WEST AND FRONT TO THE NORTH IS SPREADING
OVER MUCH OF THE CWA. CLOUDS COULD PUT A LITTLE BIT OF A DAMPER OR
DELAY ON CONVECTIVE INITIATION... BUT THERE WILL BE PLENTY OF
OPPORTUNITY FOR CLOUDS TO ERODE THUS ALLOWING BOUNDARY LAYER TO
COLLECT SOME WARMTH. IN THE VERY NEAR TERM... WILL DECREASE POPS
BUT INCREASE THEM TO CURRENT FORECAST VALUE BY MID TO LATE AFTERNOON.
AFTERNOON RAP CAPES ARE IN THE 1500 TO 3000 J/KG RANGE WITH AXIS OF
HIGHEST CAPE FROM APPROXIMALY KAND TO KCLT BY 17Z. NAM CAPES ARE A
LITTLE LOWER... GENERALLY 1000 TO 2000 J/KG... EXCEPT LESS THAN 1000
OVER MOUNTAINS. WIND PROFILES IDENTIFY VERY LITTLE SHEAR... SO PULSE
STORMS WITH LITTLE ORGANIZATION EXPECTED. QUITE POSSIBLE THAT SOME
MULTICELL CLUSTERS CAN DEVELOP... BUT RAP DCAPES ARE ONLY AROUND 500
J/KG SO THAT LOWERS CONFIDENCE A LITTLE THAT MAJOR COLD POOLS WILL
DEVELOP. HOWEVER... NAM MOVES AN AXIS OF DCAPE AROUND 1000 J/KG
ACROSS CWA FROM WEST TO EAST LATER TODAY. POTENTIAL FOR THAT FEATURE
WILL NEED TO BE MONITORED.
AS OF 605 AM EDT...MCS ACTIVITY HAS BEEN WEAKENING TO OUR WEST...BUT
IT IS STILL GENERATING QUITE A FEW CLOUD TO GROUND LIGHTNING STRIKES
OVER CENTRAL TENN AND NORTHERN ALABAMA. OVER THE PAST FEW
HOURS...THE ONLY SHOWER ACTIVITY WE HAVE SEEN HAS BEEN OVER THE FAR
WESTERN NC MTS...HOWEVER COVERAGE SHOULD BEGIN TO INCREASE LATER
THIS MORNING AS THINGS BEGIN TO HEAT UP AND THE FIRST UPPER
SHORTWAVE APPROACHES. TEMPS ARE HOLDING A BIT WARMER THAN
ANTICIPATED...SO I BUMPED UP THE MIN TEMPS A DEGREE OR 2.
PREVIOUS DISCUSSION...
A COLD FRONT WILL APPROACH FROM THE NORTH LATER TODAY...WHILE A PAIR
OF FAIRLY POTENT LOOKING H5 SHORTWAVES MOVE INTO THE BASE OF THE
TROUGH. WITH THE ATMOSPHERE REMAINING MOIST AND UNSTABLE...I KEEP
POPS AT LIKELY OVER MOST OF THE CWFA DURING THE LATE AFTERNOON AND
THRU THE LATE EVENING HOURS. CONDITIONS WILL BE SUFFICIENT FOR
SEVERE THUNDERSTORMS AGAIN...AND WITH UNIDIRECTIONAL SHEAR
PRESENT...SOME ORGANIZATION IS POSSIBLE...ESPECIALLY IN THE
PIEDMONT. WITH BETTER STEERING FLOW AND MOVING STORMS...FLOODING
SHOULD NOT BE AS MUCH OF A CONCERN...HOWEVER LOCALIZED...HIGH QPF
WILL BE POSSIBLE FROM TRAINING OR REPEATING CELLS. MAXIMUM
TEMPERATURES WILL BE NEAR NORMAL...AS LONG AS CLOUD COVER BREAKS
ENOUGH TO ALLOW SUFFICIENT HEATING.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AT 230 PM EDT FRIDAY...AN UPPER TROUGH AXIS WILL REMAIN ALONG THE
EAST COAST FROM SATURDAY NIGHT THROUGH MONDAY...WHILE A RIDGE
REMAINS OVER THE PLAINS. A WEAKENING...STALLED SURFACE FRONT WILL
REMAIN OVER OUR AREA THROUGH MONDAY. ALTHOUGH THERE DOES NOT APPEAR
TO BE MUCH ISENTROPIC UPGLIDE OVER THE BOUNDARY...SHORTWAVES MOVING
INTO THE UPPER TROUGH AND OVER THE VICINITY OF THE FRONT WILL
SUPPORT PRECIPITATION THROUGH THE PERIOD...MAXIMIZED WITH GREATER
INSTABILITY DURING DAYLIGHT HOURS. WITHOUT A STRONG LIFTING
MECHANISM...PRECIPITATION AMOUNTS ARE EXPECTED TO BE MODERATE...BUT
SEVERAL DAYS OF RAIN COULD LEAD TO SOME LOCALIZED HYDROLOGICAL
PROBLEMS WITH TIME. MINIMUM TEMPERATURES WILL BE SLIGHTLY ABOVE
NORMAL...AND MAXIMUM TEMPERATURES NEAR NORMAL.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 145 PM FRIDAY...THE CWFA WILL BE IN AN AREA BETWEEN RIDGING TO
THE SOUTH AND WEST AND NW TO SE ORIENTED NRN STREAM FLOW TO THE
NORTH. THE FLOW WILL BE CLOSE ENUF THAT WE SHUD SEE SOME EFFECT FROM
A SERIES OF WEAK SHORT WAVES MOVING THRU THE FLOW. AT THE SFC...A
BACK DOOR COLD FRONT WILL APPROACH THE AREA BUT STALL TO OUR NORTH.
A SERIES OF LOW PRESSURE WAVES WILL MOVE WEST ALONG THE FRONT. OVER
OUR CWFA...A LEE TROF AND COPIOUS LOW LEVEL MOISTURE WILL REMAIN IN
PLACE THRU THE PERIOD. THIS SHUD LEAD TO GENERALLY SCT DIURNAL
CONVECTION EACH DAY. LOWS WILL BE NEARLY STEADY AROUND 5 DEGREES
ABOVE NORMAL. HIGHS START OUT NEARLY 5 DEGREES ABOVE NORMAL THEN
FALL A COUPLE OF DEGREES BY THE END OF THE PERIOD.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
AT KCLT... UPDATED 18Z TAF INCLUDES TEMPO FOR THUNDERSTORMS DURING
AFTERNOON. OTHERWISE... CONVECTIVE CLOUD BASES 4-5K FT. SURFACE WIND
WILL BE PREDOMINANTLY FROM SOUTHWEST AT LESS THAN 10 KT... BUT
STRONG AND GUSTY VICINITY THUNDERSTORMS. THUNDERSTORMS WILL BE
CAPABLE OF PRODUCING SMALL HAIL. OVERNIGHT... EXPECT CLOUD BASES
4-5K FT CONTINUING BUT LOWERING TO 2-4 KT FT.
REMAINDER TAF SITES... SCATTERED THUNDERSTORMS DURING AFTERNOON WILL
PRODUCE CEILING AND VISIBILITY RESTRICTIONS. EXCEPT VARIABLE WIND AT
KAVL SOUTHWEST WIND LESS THAN 10 KT EXCEPT STRONG AND GUSTY NEAR
THUNDERSTORMS. THUNDERSTORMS CAPABLE OF PRODUCING SMALL HAIL.
OVERNIGHT... EXPECT CLOUD BASES 3-5K FT WITH SOME VISIBILITY
RESTRICTIONS IN FOG TOWARD SUNRISE... SPECIALLY VICINITY KAVL.
OUTLOOK...AS A COLD FRONT STALLS OVER THE AREA...SCATTERED TO
NUMEROUS (MAINLY DIURNAL) CONVECTION AND ASSOCIATED RESTRICTIONS
WILL PERSIST THROUGH THE WEEKEND. LATE NIGHT/MORNING FOG AND LOW
STRATUS PROBABILITIES WILL ALSO REMAIN FAIRLY HIGH...ESPECIALLY IN
THE MTN VALLEYS.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...JAT
NEAR TERM...LGL
SHORT TERM...JAT
LONG TERM...RWH
AVIATION...LGL
AREA FORECAST DISCUSSION...UPDATED
NWS MEMPHIS TN
1255 PM CDT FRI JUL 20 2012
.DISCUSSION...
UPDATED FOR AVIATION.
&&
.PREV DISCUSSION... /ISSUED 1100 AM CDT FRI JUL 20 2012/
UPDATE...
CONDITIONS AT 11 AM HAVE WARMED INTO THE 90S WEST OF A LINE FROM
ROUGHLY DYERSBURG TO CLARKSDALE. FURTHER EAST...SOME INFLUENCE
FROM THE ROBUST THUNDERSTORM ACTIVITY IN MIDDLE TENNESSEE /CLOUDS
AND OUTFLOWS/ HAS TEMPERED TEMPERATURES A BIT IN THE 80S. THE
925MB THERMAL RIDGE HAS NOW CENTERED ITSELF ALONG A LINE FROM
OKLAHOMA CITY EAST TO MEMPHIS. AN ILL-DEFINED FRONT APPEARS TO BE
SITUATED OVER NRN MS WITH A FEW STORMS AHEAD OF IT OVER MONROE
COUNTY.
WILL LEAVE THE CURRENT HEADLINE CONFIGURATION IN PLACE...BUT THE
EASTERN COUNTIES WITHIN THE WARNING ARE MARGINAL GIVEN THE CURRENT
CLOUD COVER. NAM 925 MB TEMPS HAVE ALSO COME DOWN A COUPLE
DEGREES...SO REDUCED HIGHS BY A DEGREE OR TWO IN MOST PLACES.
STILL THINK HEAT INDICES OF 110F ARE OBTAINABLE OVER THE DELTA AND
NEAR I-40 IN SWRN TN.
MODELS ARE RELUCTANT TO DEVELOP ANYTHING SIGNIFICANT THIS
AFTERNOON...BUT THE HRRR DOES SHOW ISOLATED CELLS DEVELOPING LATE
THIS AFTERNOON OVER MOST OF THE AREA SO DID NOT FEEL I COULD
REMOVE POPS.
BORGHOFF
PREV DISCUSSION... /ISSUED 508 AM CDT FRI JUL 20 2012/
DISCUSSION...
TEMPERATURES ARE GENERALLY RUNNING 1-5 DEGREES WARMER THAN THEY
WERE 24 HOURS AGO...AND DEW POINTS ARE AROUND 2 DEGREES WARMER
WITH THE EXCEPTION OF NORTHEAST ARKANSAS WHERE SOME DRIER AIR IS
WORKING IN. 4 AM TEMPERATURES REMAIN IN THE LOW 80S AT MANY
LOCATIONS ACROSS THE MIDSOUTH THE WARMEST READINGS ARE IN THE
DELTA AREAS...INCLUDING THE MEMPHIS METRO AREA WITH THE COOLEST
READINGS IN NORTHEAST MISSISSIPPI AND WEST TENNESSEE NEAR THE
TENNESSEE RIVER. A FEW SHOWERS DEVELOPED ALONG THE
TENNESSEE/MISSISSIPPI STATE LINE EARLIER THIS MORNING...BUT HAVE
NOW PRETTY MUCH DISSIPATED. MID AND HIGH CLOUDS OVERSPREAD MOST OF
THE MIDSOUTH HELPING TO LIMIT RADIATIONAL COOLING.
WE SHOULD SEE ANOTHER VERY HOT DAY TODAY DESPITE SOME CLOUD
COVER.AN EXCESSIVE HEAT WARNING HAS BEEN ISSUED FOR MUCH OF THE
AREA. TEMPERATURES WILL START A FEW DEGREES WARMER THAN YESTERDAY
AND WARM QUICKLY INTO THE 90S. CONVECTION WILL GET GOING FAIRLY
EARLY AND MAY PROVIDE SOME LOCALIZED RELIEF TO THE HEAT...BUT DO
NOT THINK COVERAGE...OR THE DURATION OF ANY PRECIPITATION WILL
LIMIT THE HEATING ON ANY LARGE SCALE. THE EXCEPTION MAY BE ACROSS
PORTIONS OF NORTHEAST MISSISSIPPI AND WEST TENNESSEE NEAR THE
TENNESSEE RIVER WHERE STORMS ARE EXPECTED TO BE MOST WIDESPREAD.
AFTERNOON HIGHS WILL BE AT OR ABOVE 99 DEGREES ACROSS MOST OF THE
AREA...WITH THE EXCEPTION BEING THE SAME AREA MENTIONED ABOVE. THE
WARMEST READINGS WILL LIKELY BE ACROSS THE DELTA AND NORTHEAST
ARKANSAS WHERE TEMPERATURES MAY APPROACH 105 DEGREES. HEAT INDICES
MAY CLIMB AS HIGH AS 114 DEGREES.
ALTHOUGH HEAT WILL BE THE MAIN STORY TODAY...THE STORM PREDICTION
CENTER ALSO HAS MUCH OF THE MIDSOUTH IN A SLIGHT RISK FOR SEVERE
THUNDERSTORMS. THE INTENSE HEAT AND HIGH HUMIDITY WILL RESULT IN A
VERY UNSTABLE AIRMASS FEATURING CAPE VALUES IN EXCESS OF 3500 J/KG
AND LI`S LOWER THAN -8C. THE MOST UNSTABLE CONDITIONS WILL BE
FOUND IN NORTH MISSISSIPPI AND WEST TENNESSEE. DAMAGING WIND WOULD
BE THE PRIMARY THREAT FROM THESE STORMS. OUTFLOW FROM THE ONGOING
CONVECTION IN CENTRAL TENNESSEE MAY BECOME A FOCUS FOR REDEVELOPMENT
OF STORMS DURING THE DAY TODAY. HAVE NOT SEEN ANY INDICATION THAT
IT HAS PROPAGATED VERY FAR WEST YET...BUT IT COULD LEAD TO BETTER
RAIN CHANCES FARTHER WEST DEPENDING ON ITS EVOLUTION/MOVEMENT.
A WEAK COLD FRONT WILL SINK SOUTH OF THE AREA TONIGHT ALLOWING A
COOLER DRIER AIRMASS TO FILTER INTO THE AREA. AS A RESULT...WE
PROBABLY WILL NOT NEED ANY ADDITIONAL HEAT PRODUCTS TOMORROW.
HIGHS SHOULD BE IN THE MIDDLE 90S AT MOST LOCATIONS. GUIDANCE
DIFFERS SIGNIFICANTLY WITH HIGHS OVER THE NEXT FEW DAYS...WILL
STAY ON THE WARM SIDE OF GUIDANCE BASED ON RECENT TRENDS. TOMORROW
WILL LIKELY BE THE COOLEST DAY OUT OF THE NEXT 7 UNLESS A LOCATION
IS LUCKY ENOUGH TO GET RELIEF FROM RAINFALL. HIGHS ON SATURDAY
WILL BE NEAR NORMAL ACROSS MOST OF THE AREA...GENERALLY 92 TO 94
DEGREES...ALTHOUGH PORTIONS OF EAST ARKANSAS WILL CLIMB BACK INTO
THE UPPER 90S AS A THERMAL RIDGE BUILDS EAST.
THE WARMING TREND WILL CONTINUE THROUGH THE WEEKEND AND INTO NEXT
WEEK AS A RIDGE STRENGTHENS OVER THE PLAINS AND SURFACE HIGH
PRESSURE ENCOMPASSES MUCH OT THE DEEP SOUTH. NO ORGANIZED WEATHER
IS ON THE SCOPE...ALTHOUGH WE WILL LIKELY SEE CLIMATOLOGICAL 20-30
PERCENT POPS NEARLY EVERY AFTERNOON. HIGHS FOR MOST OF THE
UPCOMING WORK WEEK WILL BE BETWEEN 95 AND 100 DEGREES.
&&
.AVIATION...
18Z TAFS
PRIMARY SHORT TERM CONCERN IS MVFR CIGS OVER WEST TN AND
NORTHEAST MS. THESE CIGS WERE EMBEDDED IN OUTFLOW FROM A LARGE
TSRA COMPLEX THAT OCCURRED OVER MIDDLE TN LAST EVENING. WHILE
MVFR CIGS WERE SLOWER TO DISSIPATE THAN EARLIER FORECAST... EXPECT
VFR TO RETURN TO TUP AND MKL BY 20Z.
REGARDING AFTERNOON TSRA... OF THE MIDSOUTH TAF SITES...TUP WAS
EARLIER THOUGHT TO HAVE A MENTIONABLE TSRA CHANCE THIS AFTERNOON.
HOWEVER... COOLER MORE STABLE AIRMASS UNDER THE MVFR WILL PRECLUDE
A TEMPO TSRA FOR THE SCHEDULED TUP TAF. SOME TS WILL BE POSSIBLE OVER
NORTH CENTRAL MS HOWEVER. BEST TSRA CHANCE WELL SOUTH OF TUP...
NEAR A CONVERGENT BOUNDARY OVER CENTRAL MS.
VFR SHOULD PREVAIL OVER THE MIDSOUTH THIS EVENING. OVERNIGHT
PERIODS MORE OF A CONCERN. GFS LAMP GUIDANCE CONTINUES TO DEVELOP
LIFR CIGS AND GROUND FOG AT MKL AFTER 09Z. NAM GUIDANCE LESS SO...
BUT DOES INDICATE THE POSSIBILITY OF POST FRONTAL MVFR CIGS EAST
OF MEM TOWARD 12Z. FOR THE 18Z TAFS... HAVE KEPT MEM SCT FOR THE
OVERNIGHT OUTBOUND PUSH.
PWB
&&
.PRELIMINARY POINT TEMPS/POPS...
MEM 101 78 95 76 / 20 10 10 0
MKL 95 72 93 70 / 20 10 10 0
JBR 102 73 96 73 / 10 0 0 0
TUP 94 74 92 73 / 50 20 20 10
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...HEAT ADVISORY UNTIL 1 AM CDT SATURDAY FOR CLAY-GREENE-LAWRENCE-
RANDOLPH.
EXCESSIVE HEAT WARNING UNTIL 1 AM CDT SATURDAY FOR CRAIGHEAD-
CRITTENDEN-CROSS-LEE AR-MISSISSIPPI-PHILLIPS-POINSETT-ST.
FRANCIS.
MO...HEAT ADVISORY UNTIL 1 AM CDT SATURDAY FOR DUNKLIN-PEMISCOT.
MS...HEAT ADVISORY UNTIL 1 AM CDT SATURDAY FOR CALHOUN-CHICKASAW-
ITAWAMBA-LEE MS-MONROE-PONTOTOC-PRENTISS-TISHOMINGO-UNION.
EXCESSIVE HEAT WARNING UNTIL 1 AM CDT SATURDAY FOR ALCORN-BENTON
MS-COAHOMA-DESOTO-LAFAYETTE-MARSHALL-PANOLA-QUITMAN-
TALLAHATCHIE-TATE-TIPPAH-TUNICA-YALOBUSHA.
TN...HEAT ADVISORY UNTIL 1 AM CDT SATURDAY FOR CARROLL-DECATUR-HARDIN-
HENDERSON-HENRY-LAKE-OBION-WEAKLEY.
EXCESSIVE HEAT WARNING UNTIL 1 AM CDT SATURDAY FOR CHESTER-
CROCKETT-DYER-FAYETTE-GIBSON-HARDEMAN-HAYWOOD-LAUDERDALE-
MADISON-MCNAIRY-SHELBY-TIPTON.
&&
$$
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1239 PM CDT FRI JUL 20 2012
.DISCUSSION...
SEE AVIATION DISCUSSION.
&&
.AVIATION...
GENERALLY VFR CONDS EXPECTED TODAY. UPPER HIGH OVER THE CENTRAL
PLAINS AND SURFACE HIGH PRESSURE OVER THE WESTERN GULF SHOULD KEEP
PRECIP TO THE EAST OF TAF SITES TODAY. FCST SOUNDINGS DON`T SHOW
MUCH IN THE WAY OF LOW CLOUDS FOR SAT MORNING BUT WILL LEAN A BIT
TOWARD PERSISTENCE AND HINT AT MVFR CIGS FOR IAH NORTHWARD.
CONVECTIVE POTENTIAL INCREASES TOMORROW AFTN (AFTER 18Z) WITH PW
VALUES APPROACHING 2 INCHES AND K INDEX VALUES APPROACHING 40. 43
&&
.PREV DISCUSSION... /ISSUED 1056 AM CDT FRI JUL 20 2012/
UPDATE...
ONLY MINOR GRID UPDATES TO INCREASE AREAWIDE DEW POINTS/RHS...AND
TO FOCUS HIGHER CHANCE POPS OVER THE SOUTHEASTERN FORECAST AREA
THIS AFTERNOON. HIGHER PVA RIDING AROUND THE SOUTHERN PERIPHERY OF
UPPER RIDGING CENTERED OVER THE WESTERN PLAINS IS CREATING THE
UNSETTLED WEATHER OFF THE COAST OF LOUISIANA. THE GENERAL
CONSENSUS AMONGST THE MODELS IS TO KEEP THE BULK OF THIS ENERGY
OVER LCH`S WESTERN CWA...TRAVELING FURTHER OFFSHORE. THUS...THERE
APPEARS TO BE A STARK DELINEATION CONCERNING RAINFALL OVER EXTREME
EASTERN TEXAS/NW GULF VERSUS MUCH DRIER CONDITIONS (PRECIPITATION-
WISE) FOR OUR REGION GOING INTO THE WEEKEND. INCREASING NEAR 2
INCH PWATS FROM THE WESTERN ADVECTION OF LOUISIANA`S MOIST AIR
MASS PER MID-LEVEL EASTERLY FLOW. FOR TODAY...LOW 90F CONVECTIVE
TEMPERATURES WITHIN A MOISTENING AND HEATED MID 90F EARLY AFTERNOON
ENVIRONMENT ENSURES AT LEAST 20 PERCENT MID-LATE AFTERNOON SHOWER/
ISOLATED STORM COVERAGE. 31
PREV DISCUSSION... /ISSUED 418 AM CDT FRI JUL 20 2012/
DISCUSSION...
RADAR AND SATELLITE LESS ACTIVE THAN LAST NIGHT. HIGH PRESSURE
RIDGE ALOFT OVER SE TX TODAY AND TOMORROW BRINGING SOME
SUBSIDENCE. HAVE REDUCED POPS FOR TODAY DOWN TO 20 PERCENT
AREAWIDE FOR THE AFTERNOON. WARMING TEMPERATURES ALOFT FROM
SUBSIDENCE BETWEEN 900-850MB SHOULD HELP CAP SOME CONVECTION AND
RESULT IN LESS COVERAGE THAN YESTERDAY. HRRR REFLECTIVITY FIELD
FORECAST COVERAGE IS VERY SPARSE AND NEAR COAST THIS AFTERNOON.
STILL SEEING MOIST PWAT AIR OVER SE TX FCST BY GFS IN THE 1.8 TO
NEAR 2.0 INCH RANGE. GFS FCST SOUNDINGS INDICATE CONVECTIVE TEMPS
IN THE MID 90S WHICH WILL BE REACHED AT KIAH LATE IN THE AFTN.
OTHERWISE HOT AND HUMID WITH AFTERNOON HEAT INDICES IN THE 100-105
RANGE.
UPPER DISTURBANCE ROTATING AROUND THE LARGER UPPER HIGH OVER KS/OK
WILL APPROACH THE CWA BY SUNDAY. GFS DOES HAVE CONVECTIVE FEEDBACK
LOOKING PCPN BULLSEYE APPROACHING SE TX ON SAT NIGHT/SUNDAY
MORNING. OTHER MODELS ARE DRY. THIS FEATURE SEEMS TO ORIGINATE
FROM CONVECTION OCCURRING EARLIER TONIGHT IN TENNESSEE. NOT OUT OF
THE QUESTION THAT SOMETHING WILL ROTATE INTO OUR AREA...AS A
RESULT I INCLUDED SLIGHT CHC TSRA FOR OVERNIGHT HOURS SAT INTO
SUNDAY MORNING. WILL NEED TO WATCH THIS FOR POSSIBLE CHANGES
DEPENDING UPON LATER OBS AND MODEL TRENDS. THIS
TROUGH/DISTURBANCE ROTATES THROUGH SE TX QUICKLY AND IS IN WEST TX
BY MONDAY NIGHT. TUTT LOW OVER CUBA/JAMAICA TONIGHT MOVES TOWARDS
THE NW GULF OF MEXICO BY EARLY NEXT WEEK...LOW POPS ARE THE RESULT
IN THE EXTENDED FORECAST SO FAR.
TENDED WARMER THAN GFS MOS GUIDANCE AGAIN THIS PACKAGE FOR MAX
TEMPS. OPERATIONAL MOS AGAIN ON THE COOL SIDE OF THE ENSEMBLES.
ETA MOS/ECM MOS ARE WARMER AND HAVE BEEN PERFORMING BETTER SO OUR
CONTINUED WARMER THAN GUIDANCE TREND FOR THE NEXT FEW DAYS SEEMS A
GOOD IDEA.
ZONES MAY BE A TAD LATE DUE TO SOME AWIPS ISSUES EARLIER THIS
MORNING...BUT NOT TOO LATE. 04
MARINE...
LIGHT SOUTHWEST TO WEST WINDS WILL CONTINUE TODAY ACROSS THE COASTAL
WATERS AS HIGH PRESSURE CONTINUES TO BUILD ACROSS HE GULF OF
MEXICO. ISOLATED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO CONTINUE
THROUGH EARLY NEXT WEEK AS A TUTT APPROACHES FROM THE EAST. 38
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 97 78 98 76 97 / 20 10 10 10 20
HOUSTON (IAH) 95 78 96 76 93 / 20 20 20 20 20
GALVESTON (GLS) 92 82 91 81 92 / 30 30 20 20 20
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...31
AVIATION/MARINE...43