Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 08/09/13
AREA FORECAST DISCUSSION
NWS LITTLE ROCK AR
659 PM CDT THU AUG 8 2013
.AVIATION...
SEVERAL ROUNDS TO SHRA/TSRA WL AFFECT MAINLY PARTS OF NRN AR DURG
THE TNGT AND FRI MRNG. STAYED CLOSE TO THE HRRR MODEL REGARDING
TIMING OF EACH ROUND OF RAINFALL. THE PRIMARY COND WL BE VFR...
WITH OCNL MVFR/IFR CONDS IN HEAVIER STORMS. LESSER RAIN CHCS
EXPECTED THE FURTHER S YOU GO ACRS THE FA...WITH VFR CONDS
PREVAILING THRU THE FCST PD. PTCHY BR /MVFR VSBYS/ WL BE POSSIBLE
ARND SUNRISE IN SOME AREAS. /44/
&&
.PREV DISCUSSION... /ISSUED 238 PM CDT THU AUG 8 2013/
..TONIGHT THROUGH SUNDAY NIGHT...
THE UPPER LEVEL PATTERN IS NOT EXPECTED TO CHANGE SUBSTANTIALLY
THROUGH THE SHORT TERM. A FLAT RIDGE ALOFT WILL PERSIST ACROSS THE
AREA...WHICH WILL SHIFT A BIT WESTWARD OVER TIME...RESULTING IN
THE UPPER LEVEL FLOW BECOMING MORE NORTHWESTERLY BY THE END OF THE
SHORT TERM.
AT THE SURFACE...A QUASI-STATIONARY FRONTAL BOUNDARY WILL CONTINUE
TO LINGER IN THE AREA TONIGHT AND TOMORROW. THE UPPER LEVEL PATTERN
AND THE NEARLY STATIONARY SURFACE BOUNDARY WILL ONCE AGAIN
CONTRIBUTE TO THE POTENTIAL FOR HEAVY RAIN ACROSS THE NORTHERN
PORTIONS OF THE FORECAST AREA AGAIN TONIGHT.
MODELS ARE AGAIN FORECASTING THE DEVELOPMENT OF AN MCS OVER THE
KS/OK REGION TONIGHT WITH THE SYSTEM DRIFTING EASTWARD OVER THE
AR/MO BORDER AREA. MODELS ARE TRYING TO TRACK THIS MCS FARTHER
NORTH...MORE INTO SOUTHERN MO...BUT DURING THE PAST FEW NIGHTS IT
SEEMS THAT THE MODELS HAVE HAD A NORTHWARD BIAS IN THE TRACK OF
THESE SYSTEMS...SO MY INSTINCT IS THAT THE NORTHERN...AND ESPECIALLY
THE NWRN COUNTIES...COULD AGAIN SEE HEAVY RAINFALL FROM AN MCS
OVERNIGHT.
PORTIONS OF NORTHERN BOONE COUNTY HAD VERY HEAVY RAINFALL FROM THE
MCS LAST NIGHT. MANY 3-4 INCH RAINFALL REPORTS WERE RECEIVED AND A
FEW WERE OVER 5 INCHES. DUAL POL RADAR ESTIMATES HAD SOME AREAS
RECEIVING IN EXCESS OF 6 INCHES. FLASH FLOODING DID OCCUR IN A
NUMBER OF AREAS...MOST NOTABLY ALONG BEAR CREEK. FLASH FLOOD
GUIDANCE FOR THIS AREA...AND ADJACENT AREAS...IS QUITE LOW FOR THE
OVERNIGHT HOURS.
WITH ALL OF THIS IN MIND...I HAVE OPTED TO ISSUE A FLASH FLOOD WATCH
FOR THIS EVENING THROUGH EARLY TOMORROW AFTERNOON FOR BOONE...
MARION...BAXTER...NEWTON...AND SEARCY COUNTIES.
ALSO...THE HEAT ADVISORY THAT IS IN EFFECT THROUGH TOMORROW
AFTERNOON NEEDED SOME ADJUSTMENTS...SO I HAVE RECONFIGURED THE
ADVISORY TO COVER ONLY THE SOUTHEASTERN QUARTER OF THE FORECAST AREA.
LONG TERM...MONDAY THROUGH THURSDAY
MODELS CONTINUE TO SHOW A PATTERN THAT SUPPORTS NWLY FLOW ALOF AND
A STALLED FRONTAL BOUNDARY IN THE STATE AT THE SURFACE THROUGH
MUCH OF THE LONG TERM PERIOD. SEVERAL IMPULSES WILL MOVE
OVERHEAD...KEEPING SLIGHT CHANCE TO CHANCE POPS IN THE FORECAST
BOTH DAY AND NIGHT. TEMPERATURES WILL BE BELOW NORMAL IN THE NORTH
PART OF THE STATE...AND AROUND NORMAL IN CENTRAL AND SOUTHERN
PARTS OF THE STATE.
ONE NOTABLE ASPECT OF THIS FORECAST TO POINT OUT WOULD BE THE
POTENTIAL FOR FLOODING. WITH SEVERAL BOUTS OF CONVECTION EXPECTED TO
MOVE ACROSS THE SAME AREAS...FLASH FLOODING AND RIVER FLOODING COULD
BECOME A CONCERN. AT THIS POINT IT IS TOO SOON TO SAY EXACTLY WHERE
AREAS OF POTENTIAL FLOODING COULD BE...BUT IT IS PROBABLY WORTH
WATCHING THE FORECAST IN THE COMING DAYS.
&&
.LZK WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY UNTIL MIDNIGHT CDT TONIGHT FOR ARKANSAS-BRADLEY-
CALHOUN-CLEVELAND-DALLAS-DESHA-DREW-FAULKNER-GRANT-JEFFERSON-
LINCOLN-LONOKE-MONROE-OUACHITA-PRAIRIE-PULASKI-SALINE.
HEAT ADVISORY FROM 1 PM TO 7 PM CDT FRIDAY FOR ARKANSAS-BRADLEY-
CALHOUN-CLEVELAND-DALLAS-DESHA-DREW-FAULKNER-GRANT-JEFFERSON-
LINCOLN-LONOKE-MONROE-OUACHITA-PRAIRIE-PULASKI-SALINE.
FLASH FLOOD WATCH UNTIL MIDNIGHT CDT TONIGHT FOR BAXTER-BOONE-
MARION-NEWTON-SEARCY.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS RENO NV
1031 PM PDT TUE AUG 6 2013
.UPDATE...
KRGX RADAR HAS BEEN WORKING FINE OVER THE LAST SEVERAL HOURS WITH NO
PROBLEMS. A FEW STORMS EARLIER OVER NORTHERN WASHOE COUNTY AND
SURPRISE VALLEY CALIFORNIA PRODUCED SOME STRONG OUTFLOW WINDS,
ALTHOUGH THE CELLS DID NOT LOOK IMPRESIVE BY ANY MEANS ON RADAR. A
GUST OF 58 MPH WAS RECORDED AT SURPRISE VALLEY RAWS AROUND 9PM THIS
EVENING.
NOCTURNAL CONVECTION CONTINUES TO BLOSSOM OVER NORTHWESTERN NEVADA
AND NORTHEASTERN CALIFORNIA AT THIS HOUR. HAVE UPDATED THE FORECAST
FOR OVERNIGHT AND EARLY WEDNESDAY MORNING TO BRING ISOLATED
THUNDERSTORMS FURTHER SOUTH INTO THE RENO-TAHOE AREA, AS WELL AS
FURTHER EAST INTO PERSHING AND CHURCHILL COUNTIES. LATEST HRRR MODEL
RUNS HAVE SHOWN CONVECTIVE DEVELOPMENT AFTER MIDNIGHT IN THESE AREAS
AS THE NEGATIVELY TILTED SHORTWAVE MOVES INTO THE AREA. THERE IS
PLENTY OF ELEVATED INSTABILITY AS SEEN ON LATEST SATELLITE IMAGERY.
ANY STORMS THAT DO DEVELOP WILL BE VERY HIGH BASED AND FAST MOVING
WITH LITTLE RAINFALL POSSIBLE. HOON
&&
.PREVIOUS DISCUSSION... /ISSUED 546 PM PDT TUE AUG 6 2013/
UPDATE...
MADE AN UPDATE TO THE FORECAST TO INCLUDE AREAS OF SMOKE AND HAZE
IN MONO AND ALPINE COUNTIES TONIGHT AND WEDNESDAY. ALSO, THE WSR-
88D RADAR ON VIRGINIA PEAK HAS EXPERIENCED ANOTHER OUTAGE OF
WIDEBAND COMMUNICATIONS. TECHNICIANS HAVE BEEN ALERTED TO THE
OUTAGE AND ARE WORKING TO FIX THE PROBLEM AS SOON AS POSSIBLE.
AS FOR THE STORMS ALONG THE SIERRA FRONT, WE CONTINUE TO MONITOR
THE STORMS USING RADARS IN THE SACRAMENTO AND HANFORD CALIFORNIA.
NONE OF THE STORMS LOOK PARTICULARLY STRONG, ALTHOUGH WITH THE
VERY DRY BOUNDARY LAYER (AS SEEN ON THE 00Z SOUNDING), STRONG
GUSTY OUTFLOW WINDS UP TO 50 MPH OR MORE ARE POSSIBLE WITH EVEN
WEAK STORMS. HOON
PREVIOUS DISCUSSION... /ISSUED 311 PM PDT TUE AUG 6 2013/
SYNOPSIS...
LOW PRESSURE OFF THE CALIFORNIA COAST WILL EDGE CLOSER TO EASTERN
CALIFORNIA AND WESTERN NEVADA THIS WEEK. INCREASING MOISTURE AND
INSTABILITY FROM THE LOW WILL BRING THE THREAT OF THUNDERSTORMS
THIS WEEK...MOST WIDESPREAD NORTH OF INTERSTATE 80. TEMPERATURES
WILL FALL TO 5 TO 10 DEGREES BELOW AVERAGE LATE THIS WEEK.
SHORT TERM...
MAIN CHANGE TO THE SHORT TERM FORECAST WAS TO INCREASE THUNDERSTORM
COVERAGE THURSDAY MORNING OVER NORTHEAST CALIFORNIA AND WESTERN
NEVADA NORTH OF SUSANVILLE AND LOVELOCK.
LOOKING AT THE VISIBLE SATELLITE THIS AFTERNOON THERE ARE TWO AREAS
OF NOTE. IN/NEAR THE SIERRA SOUTH OF HIGHWAY 50, DAYTIME HEATING AND
SOUTHEAST FLOW ALOFT HAS ALLOWED CUMULUS TO BUILD UP THE CREST. SO
FAR IN THE VISIBLE SATELLITE AND PER WEB CAMS, THE CUMULUS LOOKS
MODEST BUT SEVERAL HOURS OF ADDITIONAL HEATING SHOULD ALLOW A FEW
HIGH BASED SHOWERS AND THUNDERSTORMS TO DEVELOP AND SPREAD NORTH
UP THE CREST INTO NORTHEAST CALIFORNIA AND INTO FAR WESTERN
NEVADA. THE OTHER AREA OF NOTE IS NORTH OF GERLACH AND SUSANVILLE
WHERE DIVERGENCE ALOFT BETWEEN THE COASTAL UPPER LOW AND A RIDGE
AXIS OVER NORTHEAST NEVADA IS PRODUCING ELEVATED SHOWERS AND,
RECENTLY, A THUNDERSTORM.
MOVING ON TO THE FORECAST TONIGHT THROUGH THURSDAY NIGHT, THE
UPPER LOW OFF THE NORTHERN CALIFORNIA COAST WILL MOVE SLOWLY EAST-
NORTHEAST TOWARDS CAPE MENDOCINO. TWO UPPER WAVES WILL MOVE AROUND
THE LOW, ONE TONIGHT AND THE SECOND THURSDAY. THE WAVES WILL BRING
ISOLATED TO SCATTERED THUNDERSTORMS (BOTH ELEVATED AND SURFACE-
BASED), WITH THE MOST WIDESPREAD THUNDERSTORMS EXPECTED NORTH OF
INTERSTATE 80.
AS FAR AS THE FIRST WAVE TONIGHT, IT IS CURRENTLY APPROACHING THE
CALIFORNIA COAST WITH AN ASSOCIATED JET STREAK MOVING OVER THE
SAN FRANCISCO AREA. THIS IS FIRING UP ELEVATED CONVECTION OVER
NORTHERN CALIFORNIA AND, AS THE DISTURBANCE MOVES INLAND LATE
TONIGHT, OVER LASSEN, NORTHERN WASHOE AND MODOC COUNTIES. THEY
ARE ONLY EXPECTED TO BE ISOLATED AS THE MAIN UPPER FORCING REMAINS
OVER NORTHERN CALIFORNIA AND SOUTHERN OREGON THROUGH WEDNESDAY
MORNING.
ON WEDNESDAY, THE FIRST UPPER WAVE WILL PASS INTO SOUTHERN OREGON.
AFTER A FEW ISOLATED THUNDERSTORMS EARLY OVER FAR NORTHEAST
CALIFORNIA AND NEAR THE SURPRISE VALLEY, DIURNAL CONVECTION WILL
FIRE UP BY EARLY AFTERNOON. THE BEST COVERAGE SHOULD BE NORTH OF
SUSANVILLE AND GERLACH AS A RESIDUAL MOISTURE BOUNDARY AND
CONVERGENT WESTERLY FLOW DEVELOPS DOWNWIND OF LASSEN PEAK.
ISOLATED THUNDERSTORMS ARE ALSO POSSIBLE SOUTH OF HIGHWAY 50 IN
THE BASIN AND RANGE AS WESTERLY WINDS KICK OFF THE SIERRA IN THE
AFTERNOON AND EVENING. THAT AREA WILL BE MORE STABLE THAN FURTHER
NORTH AS A DRY SLOT INVADES IN THE POST-WAVE AIRMASS SO STORMS
MAY HAVE A LITTLE TROUBLE GETTING GOING THERE.
WEDNESDAY NIGHT AND THURSDAY MORNING, ANOTHER ROUND OF NOCTURNAL
CONVECTION IS POSSIBLE NORTH OF INTERSTATE 80 AS THE SECOND UPPER
WAVE MOVES OVERHEAD. SEE THE FIRE WEATHER DISCUSSION FOR MORE
DETAILS ON THAT WAVE. THURSDAY AFTERNOON AND EVENING A JET STREAK
MOVES OVER THE NORTHERN SIERRA FOR A BETTER SHOT AT DIURNAL
CONVECTION DOWN TO THE RENO-TAHOE AREA BY EARLY EVENING. SNYDER
LONG TERM...FRIDAY THROUGH TUESDAY...
FEW CHANGES TO THE EXTENDED FORECAST AS MEDIUM RANGE MODELS CONTINUE
TO MAINTAIN GOOD AGREEMENT WITH THE CUTOFF LOW PRESSURE OVER THE
WEST COAST. MAIN CHANGE WAS TO COOL HIGH TEMPERATURES ON FRIDAY
AND SATURDAY A FEW DEGREES AS THE CORE OF THE LOW MOVES OVER
NORTHERN CALIFORNIA AND FAR NORTHWEST NEVADA.
ON FRIDAY ISOLATED THUNDERSTORMS WILL CONTINUE IN THE NORTHERN
SIERRA NORTH OF LAKE TAHOE WITH THE POSSIBILITY OF NOCTURNAL STORMS
CONTINUING MAINLY NORTH OF SUSANVILLE. ON SATURDAY ISOLATED
THUNDERSTORMS MAY STILL BE POSSIBLE NORTH OF SUSANVILLE AS THE LOW
LIFTS OUT OF THE AREA. FRIDAY SHOULD BE THE COLDEST DAY OF THE WEEK
WITH TEMPERATURES IN WESTERN NEVADA IN THE MID 80`S AND MID 70`S IN
THE SIERRA.
BY SUNDAY THE LOW BEGINS TO WEAKEN AND MOVE NORTH INTO OREGON AS
HIGH PRESSURE REBUILDS OVER THE FOUR CORNERS. THE BEST INSTABILITY
MOVES NORTH WITH THE LOW PRESSURE LEAVING ONLY A FEW CUMULUS CLOUDS
ALONG THE SIERRA. BY MONDAY TEMPERATURES WILL RETURN TO NORMAL WITH
WESTERN NEVADA RETURNING TO AROUND 90 DEGREES AND THE SIERRA AROUND
80. TOLBY
AVIATION...
CUMULUS WITH ISOLATED HIGH-BASED STORMS ARE BUILDING NORTH IN AND
NEAR THE SIERRA THIS AFTERNOON. OUTFLOW WINDS TO 40-45 KTS ARE
POSSIBLE AROUND STORMS WITH THE PRIMARY CIG/VSBY RESTRICTIONS
EXPECTED OVER HIGHER TERRAIN WHERE HEAVIER RAIN WILL REACH THE
GROUND.
STILL NOT PLANNING ON MENTIONING ANY THUNDER AT KTRK/KTVL/KRNO/KMMH
TERMINALS THIS EVENING AS CLOUDS ARE PUSHING EAST OF THE CREST
TOWARDS THE PINE NUT RANGE (EASTERN DOUGLAS COUNTY) BEFORE THEY
REACH NORTH TO HIGHWAY 50. AS FAR AS SMOKE FROM FIRES WEST OF THE
SIERRA CREST, IT WILL AFFECT VSBYS THROUGH THIS EVENING IN MONO
COUNTY ESPECIALLY WEST OF BRIDGEPORT AND SOUTH OF MONO LAKE.
ISOLATED THUNDERSTORMS MAY PERSIST OVER AREAS NORTH OF SUSANVILLE
THROUGH THE NIGHT WITH GUSTY OUTFLOW WINDS. ON WEDNESDAY,
THUNDERSTORMS SHOULD BE RESTRICTED TO SOUTH OF HIGHWAY 50 AND
NORTH OF SUSANVILLE AND GERLACH. SNYDER
FIRE WEATHER...
BIGGEST CONCERN REMAINS THUNDERSTORMS THURSDAY. UNTIL THEN, STILL
EXPECT ISOLATED THUNDERSTORMS NEAR AND EAST OF THE SIERRA CREST THIS
EVENING. BUILDING CUMULUS ALREADY OVER MONO COUNTY, WITH SOME NOW
DEVELOPING A LITTLE FURTHER NORTH. ONLY EXPECTING A FEW STORMS BUT
THEY SHOULD BE DRY WITH VERY DRY LOW LEVELS AND STORM MOTIONS NWD
AROUND 20 MPH.
OTHER CONCERN IS IMPRESSIVE MID/UPPER LEVEL WAVE OFF POINT
CONCEPTION. FORCING AHEAD OF IT IS IMPRESSIVE AND ALREADY GETTING A
FEW ISOLATED C-G STRIKES OVER THE SACRAMENTO VALLEY SHOWING THE
ELEVATED INSTABILITY. THIS WILL MOVE THROUGH OVERNIGHT WITH MODELS
SHOWING IMPRESSIVE FORCING AND INSTABILITY AHEAD OF THE WAVE. IT
LOOKS TO PASS THROUGH NW CA AND SW OREGON AFTER 12Z SO WE WILL ONLY
BE ON THE FRINGE. WILL CONTINUE WITH ISOLATED DRY THUNDERSTORMS FOR
LASSEN AND PLUMAS COUNTIES NORTH OF HWY 70 TONIGHT INTO EXTREME NW
NEVADA. BEST ACTION WILL BE FURTHER NORTH AND WEST.
DRIER AIR AND A BIT STRONGER WEST FLOW WILL OCCUR IN THE WAKE OF THE
WAVE WEDNESDAY. THEREFORE, STILL EXPECT MAIN THREAT FOR
THUNDERSTORMS NORTH OF SUSANVILLE/GERLACH. MAY SEE SOME SCT COVERAGE
RIGHT NEAR THE OREGON BORDER WITH HYBRID WET/DRY STORMS. IT IS A
CONCERN, BUT WITH LIMITED AREA AFFECT WILL NOT ISSUE A WATCH/WARNING
THERE.
AS FOR THURSDAY, AN UPPER WAVE IS EXPECTED TO MOVE IN THURSDAY
MORNING WITH GOOD UPPER JET SUPPORT. IN ADDITION, MID-LEVEL MOISTURE
WILL INCREASE WITH THUNDERSTORMS LIKELY TO START AROUND SUNRISE. THE
BEST FORCING AND MOISTURE REMAIN NORTH OF I-80 WITH SCATTERED STORMS
INTO THE AFTERNOON. LOW LEVEL MOISTURE WILL ALSO INCREASE DURING THE
DAY, BUT THE FAST STORM MOTIONS OF 20-25 MPH WILL LIKELY KEEP THE
STORMS IN A HYBRID WET/DRY MODE. HAVE ISSUED A WATCH FOR THE ZONES
NORTH OF I-80; 270, 271, 278, 453, 458. 271 MAY BE A BIT TOO WET AS
WE GO FURTHER INTO THE DAY THURSDAY, BUT GIVEN THE THREAT IN THE
MORNING WHEN STORMS WOULD BE DRIER, I THOUGHT IT WOULD BE PRUDENT TO
ADD IT. WALLMANN
&&
.REV WATCHES/WARNINGS/ADVISORIES...
NV...FIRE WEATHER WATCH FROM LATE WEDNESDAY NIGHT THROUGH THURSDAY
EVENING NVZ458.
FIRE WEATHER WATCH FROM LATE WEDNESDAY NIGHT THROUGH THURSDAY
EVENING NVZ453.
CA...FIRE WEATHER WATCH FROM LATE WEDNESDAY NIGHT THROUGH THURSDAY
EVENING CAZ270-271-278.
&&
$$
FOR MORE INFORMATION FROM THE NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/RENO (ALL LOWER CASE)
AREA FORECAST DISCUSSION...UPDATED
NWS RENO NV
1021 PM PDT TUE AUG 6 2013
.UPDATE...
KRGX RADAR HAS BEEN WORKING FINE OVER THE LAST SEVERAL HOURS WITH
NO PROBLEMS. NOCTURNAL CONVECTION CONTINUES TO BLOSSOM OVER
NORTHWESTERN NEVADA AND NORTHEASTERN CALIFORNIA AT THIS HOUR. HAVE
UPDATED THE FORECAST FOR OVERNIGHT AND EARLY WEDNESDAY MORNING TO
BRING ISOLATED THUNDERSTORMS FURTHER SOUTH INTO THE RENO-TAHOE
AREA, AS WELL AS FURTHER EAST INTO PERSHING AND CHURCHILL
COUNTIES. LATEST HRRR MODEL RUNS HAVE SHOWN CONVECTIVE DEVELOPMENT
AFTER MIDNIGHT IN THESE AREAS AS THE NEGATIVELY TILTED SHORTWAVE
MOVES INTO THE AREA. THERE IS PLENTY OF ELEVATED INSTABILITY AS
SEEN ON LATEST SATELLITE IMAGERY. ANY STORMS THAT DO DEVELOP WILL
BE VERY HIGH BASED AND FAST MOVING WITH LITTLE RAINFALL POSSIBLE.
HOON
&&
.PREVIOUS DISCUSSION... /ISSUED 546 PM PDT TUE AUG 6 2013/
UPDATE...
MADE AN UPDATE TO THE FORECAST TO INCLUDE AREAS OF SMOKE AND HAZE
IN MONO AND ALPINE COUNTIES TONIGHT AND WEDNESDAY. ALSO, THE WSR-
88D RADAR ON VIRGINIA PEAK HAS EXPERIENCED ANOTHER OUTAGE OF
WIDEBAND COMMUNICATIONS. TECHNICIANS HAVE BEEN ALERTED TO THE
OUTAGE AND ARE WORKING TO FIX THE PROBLEM AS SOON AS POSSIBLE.
AS FOR THE STORMS ALONG THE SIERRA FRONT, WE CONTINUE TO MONITOR
THE STORMS USING RADARS IN THE SACRAMENTO AND HANFORD CALIFORNIA.
NONE OF THE STORMS LOOK PARTICULARLY STRONG, ALTHOUGH WITH THE
VERY DRY BOUNDARY LAYER (AS SEEN ON THE 00Z SOUNDING), STRONG
GUSTY OUTFLOW WINDS UP TO 50 MPH OR MORE ARE POSSIBLE WITH EVEN
WEAK STORMS. HOON
PREVIOUS DISCUSSION... /ISSUED 311 PM PDT TUE AUG 6 2013/
SYNOPSIS...
LOW PRESSURE OFF THE CALIFORNIA COAST WILL EDGE CLOSER TO EASTERN
CALIFORNIA AND WESTERN NEVADA THIS WEEK. INCREASING MOISTURE AND
INSTABILITY FROM THE LOW WILL BRING THE THREAT OF THUNDERSTORMS
THIS WEEK...MOST WIDESPREAD NORTH OF INTERSTATE 80. TEMPERATURES
WILL FALL TO 5 TO 10 DEGREES BELOW AVERAGE LATE THIS WEEK.
SHORT TERM...
MAIN CHANGE TO THE SHORT TERM FORECAST WAS TO INCREASE THUNDERSTORM
COVERAGE THURSDAY MORNING OVER NORTHEAST CALIFORNIA AND WESTERN
NEVADA NORTH OF SUSANVILLE AND LOVELOCK.
LOOKING AT THE VISIBLE SATELLITE THIS AFTERNOON THERE ARE TWO AREAS
OF NOTE. IN/NEAR THE SIERRA SOUTH OF HIGHWAY 50, DAYTIME HEATING AND
SOUTHEAST FLOW ALOFT HAS ALLOWED CUMULUS TO BUILD UP THE CREST. SO
FAR IN THE VISIBLE SATELLITE AND PER WEB CAMS, THE CUMULUS LOOKS
MODEST BUT SEVERAL HOURS OF ADDITIONAL HEATING SHOULD ALLOW A FEW
HIGH BASED SHOWERS AND THUNDERSTORMS TO DEVELOP AND SPREAD NORTH
UP THE CREST INTO NORTHEAST CALIFORNIA AND INTO FAR WESTERN
NEVADA. THE OTHER AREA OF NOTE IS NORTH OF GERLACH AND SUSANVILLE
WHERE DIVERGENCE ALOFT BETWEEN THE COASTAL UPPER LOW AND A RIDGE
AXIS OVER NORTHEAST NEVADA IS PRODUCING ELEVATED SHOWERS AND,
RECENTLY, A THUNDERSTORM.
MOVING ON TO THE FORECAST TONIGHT THROUGH THURSDAY NIGHT, THE
UPPER LOW OFF THE NORTHERN CALIFORNIA COAST WILL MOVE SLOWLY EAST-
NORTHEAST TOWARDS CAPE MENDOCINO. TWO UPPER WAVES WILL MOVE AROUND
THE LOW, ONE TONIGHT AND THE SECOND THURSDAY. THE WAVES WILL BRING
ISOLATED TO SCATTERED THUNDERSTORMS (BOTH ELEVATED AND SURFACE-
BASED), WITH THE MOST WIDESPREAD THUNDERSTORMS EXPECTED NORTH OF
INTERSTATE 80.
AS FAR AS THE FIRST WAVE TONIGHT, IT IS CURRENTLY APPROACHING THE
CALIFORNIA COAST WITH AN ASSOCIATED JET STREAK MOVING OVER THE
SAN FRANCISCO AREA. THIS IS FIRING UP ELEVATED CONVECTION OVER
NORTHERN CALIFORNIA AND, AS THE DISTURBANCE MOVES INLAND LATE
TONIGHT, OVER LASSEN, NORTHERN WASHOE AND MODOC COUNTIES. THEY
ARE ONLY EXPECTED TO BE ISOLATED AS THE MAIN UPPER FORCING REMAINS
OVER NORTHERN CALIFORNIA AND SOUTHERN OREGON THROUGH WEDNESDAY
MORNING.
ON WEDNESDAY, THE FIRST UPPER WAVE WILL PASS INTO SOUTHERN OREGON.
AFTER A FEW ISOLATED THUNDERSTORMS EARLY OVER FAR NORTHEAST
CALIFORNIA AND NEAR THE SURPRISE VALLEY, DIURNAL CONVECTION WILL
FIRE UP BY EARLY AFTERNOON. THE BEST COVERAGE SHOULD BE NORTH OF
SUSANVILLE AND GERLACH AS A RESIDUAL MOISTURE BOUNDARY AND
CONVERGENT WESTERLY FLOW DEVELOPS DOWNWIND OF LASSEN PEAK.
ISOLATED THUNDERSTORMS ARE ALSO POSSIBLE SOUTH OF HIGHWAY 50 IN
THE BASIN AND RANGE AS WESTERLY WINDS KICK OFF THE SIERRA IN THE
AFTERNOON AND EVENING. THAT AREA WILL BE MORE STABLE THAN FURTHER
NORTH AS A DRY SLOT INVADES IN THE POST-WAVE AIRMASS SO STORMS
MAY HAVE A LITTLE TROUBLE GETTING GOING THERE.
WEDNESDAY NIGHT AND THURSDAY MORNING, ANOTHER ROUND OF NOCTURNAL
CONVECTION IS POSSIBLE NORTH OF INTERSTATE 80 AS THE SECOND UPPER
WAVE MOVES OVERHEAD. SEE THE FIRE WEATHER DISCUSSION FOR MORE
DETAILS ON THAT WAVE. THURSDAY AFTERNOON AND EVENING A JET STREAK
MOVES OVER THE NORTHERN SIERRA FOR A BETTER SHOT AT DIURNAL
CONVECTION DOWN TO THE RENO-TAHOE AREA BY EARLY EVENING. SNYDER
LONG TERM...FRIDAY THROUGH TUESDAY...
FEW CHANGES TO THE EXTENDED FORECAST AS MEDIUM RANGE MODELS CONTINUE
TO MAINTAIN GOOD AGREEMENT WITH THE CUTOFF LOW PRESSURE OVER THE
WEST COAST. MAIN CHANGE WAS TO COOL HIGH TEMPERATURES ON FRIDAY
AND SATURDAY A FEW DEGREES AS THE CORE OF THE LOW MOVES OVER
NORTHERN CALIFORNIA AND FAR NORTHWEST NEVADA.
ON FRIDAY ISOLATED THUNDERSTORMS WILL CONTINUE IN THE NORTHERN
SIERRA NORTH OF LAKE TAHOE WITH THE POSSIBILITY OF NOCTURNAL STORMS
CONTINUING MAINLY NORTH OF SUSANVILLE. ON SATURDAY ISOLATED
THUNDERSTORMS MAY STILL BE POSSIBLE NORTH OF SUSANVILLE AS THE LOW
LIFTS OUT OF THE AREA. FRIDAY SHOULD BE THE COLDEST DAY OF THE WEEK
WITH TEMPERATURES IN WESTERN NEVADA IN THE MID 80`S AND MID 70`S IN
THE SIERRA.
BY SUNDAY THE LOW BEGINS TO WEAKEN AND MOVE NORTH INTO OREGON AS
HIGH PRESSURE REBUILDS OVER THE FOUR CORNERS. THE BEST INSTABILITY
MOVES NORTH WITH THE LOW PRESSURE LEAVING ONLY A FEW CUMULUS CLOUDS
ALONG THE SIERRA. BY MONDAY TEMPERATURES WILL RETURN TO NORMAL WITH
WESTERN NEVADA RETURNING TO AROUND 90 DEGREES AND THE SIERRA AROUND
80. TOLBY
AVIATION...
CUMULUS WITH ISOLATED HIGH-BASED STORMS ARE BUILDING NORTH IN AND
NEAR THE SIERRA THIS AFTERNOON. OUTFLOW WINDS TO 40-45 KTS ARE
POSSIBLE AROUND STORMS WITH THE PRIMARY CIG/VSBY RESTRICTIONS
EXPECTED OVER HIGHER TERRAIN WHERE HEAVIER RAIN WILL REACH THE
GROUND.
STILL NOT PLANNING ON MENTIONING ANY THUNDER AT KTRK/KTVL/KRNO/KMMH
TERMINALS THIS EVENING AS CLOUDS ARE PUSHING EAST OF THE CREST
TOWARDS THE PINE NUT RANGE (EASTERN DOUGLAS COUNTY) BEFORE THEY
REACH NORTH TO HIGHWAY 50. AS FAR AS SMOKE FROM FIRES WEST OF THE
SIERRA CREST, IT WILL AFFECT VSBYS THROUGH THIS EVENING IN MONO
COUNTY ESPECIALLY WEST OF BRIDGEPORT AND SOUTH OF MONO LAKE.
ISOLATED THUNDERSTORMS MAY PERSIST OVER AREAS NORTH OF SUSANVILLE
THROUGH THE NIGHT WITH GUSTY OUTFLOW WINDS. ON WEDNESDAY,
THUNDERSTORMS SHOULD BE RESTRICTED TO SOUTH OF HIGHWAY 50 AND
NORTH OF SUSANVILLE AND GERLACH. SNYDER
FIRE WEATHER...
BIGGEST CONCERN REMAINS THUNDERSTORMS THURSDAY. UNTIL THEN, STILL
EXPECT ISOLATED THUNDERSTORMS NEAR AND EAST OF THE SIERRA CREST THIS
EVENING. BUILDING CUMULUS ALREADY OVER MONO COUNTY, WITH SOME NOW
DEVELOPING A LITTLE FURTHER NORTH. ONLY EXPECTING A FEW STORMS BUT
THEY SHOULD BE DRY WITH VERY DRY LOW LEVELS AND STORM MOTIONS NWD
AROUND 20 MPH.
OTHER CONCERN IS IMPRESSIVE MID/UPPER LEVEL WAVE OFF POINT
CONCEPTION. FORCING AHEAD OF IT IS IMPRESSIVE AND ALREADY GETTING A
FEW ISOLATED C-G STRIKES OVER THE SACRAMENTO VALLEY SHOWING THE
ELEVATED INSTABILITY. THIS WILL MOVE THROUGH OVERNIGHT WITH MODELS
SHOWING IMPRESSIVE FORCING AND INSTABILITY AHEAD OF THE WAVE. IT
LOOKS TO PASS THROUGH NW CA AND SW OREGON AFTER 12Z SO WE WILL ONLY
BE ON THE FRINGE. WILL CONTINUE WITH ISOLATED DRY THUNDERSTORMS FOR
LASSEN AND PLUMAS COUNTIES NORTH OF HWY 70 TONIGHT INTO EXTREME NW
NEVADA. BEST ACTION WILL BE FURTHER NORTH AND WEST.
DRIER AIR AND A BIT STRONGER WEST FLOW WILL OCCUR IN THE WAKE OF THE
WAVE WEDNESDAY. THEREFORE, STILL EXPECT MAIN THREAT FOR
THUNDERSTORMS NORTH OF SUSANVILLE/GERLACH. MAY SEE SOME SCT COVERAGE
RIGHT NEAR THE OREGON BORDER WITH HYBRID WET/DRY STORMS. IT IS A
CONCERN, BUT WITH LIMITED AREA AFFECT WILL NOT ISSUE A WATCH/WARNING
THERE.
AS FOR THURSDAY, AN UPPER WAVE IS EXPECTED TO MOVE IN THURSDAY
MORNING WITH GOOD UPPER JET SUPPORT. IN ADDITION, MID-LEVEL MOISTURE
WILL INCREASE WITH THUNDERSTORMS LIKELY TO START AROUND SUNRISE. THE
BEST FORCING AND MOISTURE REMAIN NORTH OF I-80 WITH SCATTERED STORMS
INTO THE AFTERNOON. LOW LEVEL MOISTURE WILL ALSO INCREASE DURING THE
DAY, BUT THE FAST STORM MOTIONS OF 20-25 MPH WILL LIKELY KEEP THE
STORMS IN A HYBRID WET/DRY MODE. HAVE ISSUED A WATCH FOR THE ZONES
NORTH OF I-80; 270, 271, 278, 453, 458. 271 MAY BE A BIT TOO WET AS
WE GO FURTHER INTO THE DAY THURSDAY, BUT GIVEN THE THREAT IN THE
MORNING WHEN STORMS WOULD BE DRIER, I THOUGHT IT WOULD BE PRUDENT TO
ADD IT. WALLMANN
&&
.REV WATCHES/WARNINGS/ADVISORIES...
NV...FIRE WEATHER WATCH FROM LATE WEDNESDAY NIGHT THROUGH THURSDAY
EVENING NVZ458.
FIRE WEATHER WATCH FROM LATE WEDNESDAY NIGHT THROUGH THURSDAY
EVENING NVZ453.
CA...FIRE WEATHER WATCH FROM LATE WEDNESDAY NIGHT THROUGH THURSDAY
EVENING CAZ270-271-278.
&&
$$
FOR MORE INFORMATION FROM THE NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/RENO (ALL LOWER CASE)
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
351 PM MDT WED AUG 7 2013
.SHORT TERM...A COMPLEX PICTURE TODAY WITH SEVERAL UPPER LEVEL
SHORTWAVES EMBEDDED WITHIN AN OVERALL WEAK TROUGH CENTERED BACK
TOWARDS THE FOUR CORNERS REGION. SATELLITE WATER VAPOR LOOP CAPTURES
THINGS BEST. ONE FEATURE WENT BY THIS MORNING INTO EARLY AFTERNOON
WITH SOME THUNDERSTORM ACTIVITY EAST OF DENVER THAT HAS SINCE
MOVED OFF AND WEAKENED. THE PLATTEVILLE PROFILER SHOWS THIS I
BELIEVE CENTERED AROUND 600 MB. WIDESPREAD CLOUDINESS BUT NOT MUCH
RAIN FOR MOST OF THE REST OF THE FORECAST AREA WHICH HAS KEPT
TEMPERATURES ON THE COOL SIDE AND THUNDER LIMITED SO FAR. MORE SUN
AND WARMER CONDITIONS HAVE BEEN PRESENT SOUTH OF THE PALMER DIVIDE
AND A SECOND WAVE SEEN IN THE WATER VAPOR IMAGERY AND CAPTURED BY
THE RAP ANALYSES IS MOVING INTO THIS AREA WITH THUNDERSTORMS
RAPIDLY DEVELOPING. THESE SHOULD MOVE INTO THE PALMER DIVIDE
REGION OVER THE NEXT SEVERAL HOURS SO WILL CONTINUE THE FLASH
FLOOD WATCH. ALTHOUGH SURFACE WARMING HAS BEEN LIMITED ACROSS THE
PALMER DIVIDE COMPARED TO SOUTHEAST COLORADO DEW POINTS ARE QUITE
HIGH WITH 61 NOW AT LIMON. ANOTHER WAVE IS FOUND FARTHER SOUTH
MOVING NORTH INTO SOUTHWEST COLORADO AND THIS FEATURE IF IT HOLDS
TOGETHER COULD HELP SUPPORT MORE ACTIVITY LATER TONIGHT AGAIN TO
THE EAST OF DENVER. SEE THIS SECOND WAVE IN THE LATEST HRRR
FORECAST RUN FROM 19Z BUT HRRR KEEPS IT RATHER FAR TO THE SOUTH AS
IT APPROACHES NEAR 06Z. MAYBE TOO FAR SOUTH AS IT ALSO SEEMS TO BE
WITH THE CURRENT WAVE OF STORMS MOVING EAST OF PUB AND COS. MEANWHILE
AN UPPER LEVEL CIRCULATION REMAINS BEHIND NEAR THE FOUR CORNERS
AND WHAT IS LEFT OF THIS COULD BE A FACTOR TOMORROW OR SHIFT MORE
TO THE EAST.
THE MAIN PRECIPITATION LOOKS LIKE IT WILL CONTINUE TO STAY EAST
AND SOUTH OF DENVER. THERE IS ANOTHER AREA OF MORE SCATTERED
THUNDERSTORMS OVER THE FOOTHILLS OVER LARIMER COUNTY AND SOME OF
THESE COULD MOVE ONTO THE ADJACENT FRONT RANGE. MEANWHILE THERE
CONTINUES TO BE A WIDE RANGE OF MODEL SOLUTIONS EVEN FOR THE
PRECIPITATION IN THE NEXT 6 TO 12 HOURS. THE 12Z GFS HAD THE MOST
ORGANIZED WIDESPREAD HEAVY RAIN AREA AS IT ORGANIZED ONE OF THE
ABOVE NOTED FEATURES INTO A COMPACT CIRCULATION AT 700 MB. OTHER
MODELS KEEP MOST OF THE PRECIP MUCH FARTHER TO THE SOUTH. LATEST
HRRR HAS A WAVE OF PRECIP NEXT FEW HOURS THEN STAYS FARTHER SOUTH.
SOMETHING IN BETWEEN THE EXTREMES LOOKS MOST LIKELY AND KEPT
HIGHEST POPS OVER THE PALMER DIVIDE AND FAR EASTERN ZONES
LINGERING INTO THURSDAY MORNING.
.LONG TERM...BACK EDGE OF MID LEVEL TROUGH TO BE EXITING EASTERN
COLORADO DURING THE EVENING WITH WEAK SUBSIDENCE SPREADING ACROSS
THE AREA. FLOW ALOFT APPEARS A BIT SPLIT WITH WESTERLY FLOW ACROSS
SOUTHERN COLORADO AND NORTHWEST FLOW ALOFT OVER NORTHERN
COLORADO...WITH THE MAIN BATCH OF SUBTROPICAL MOISTURE TO THE WEST
AND SOUTH OF THE CFWA. STILL ENOUGH MOISTURE AND WEAK INSTABILITY
DURING THE EVENING FOR SOME THUNDERSTORMS WHILE AIRMASS A BIT MORE
STABLE OVER PLAINS. SHOULD SEE STORMS END ACROSS PLAINS AROUND
MIDNIGHT AS AIRMASS CONTINUES TO STABILIZE WITH PERHAPS A FEW
STORMS LINGERING OVERNIGHT ACROSS THE HIGH COUNTRY. ON
FRIDAY...FLOW ALOFT BECOMES MORE WESTERLY BY THE AFTERNOON AS
MODEL CONSENSUS SHOWS A WEAK UPPER TROUGH MOVES ACROSS NORTHERN
WYOMING. HOWEVER...700 MB LOW IS STILL MORE SOUTHWEST...WHICH
SHOULD ALLOW SOME INCREASE IN SUBTROPICAL MOISTURE OVER THE AREA.
SURFACE HIGH TO PUSH ACROSS INTO CENTRAL PLAINS WITH LOW LEVEL
FLOW BECOMING SOUTHEAST BY THE AFTERNOON. THIS WILL ALLOW SOME
INCREASE IN LOW LEVEL MOISTURE ALONG WITH SLIGHTLY COOLER
TEMPERATURES. FORECAST SOUNDINGS SHOW A BIT OF A CAP ACROSS THE
PLAINS. SO BEST CHANCE FOR THUNDERSTORMS TO OCCUR ACROSS THE
MOUNTAINS AND FOOTHILLS DURING THE AFTERNOON AND EVENING WITH MOST
STORMS ENDING AROUND MIDNIGHT. ON SATURDAY...SOUTHWEST FLOW ALOFT
TO PREVAIL WITH SOME INCREASE IN SUBTROPICAL MOISTURE...WHICH
SHOULD LEAD TO A CHANCE OF THUNDERSTORMS OVER THE HIGH COUNTRY.
ACROSS PLAINS...AIRMASS STILL FAIRLY CAPPED AS NOTED BY FORECAST
SOUNDINGS WHICH SHOULD LIMIT THUNDERSTORM DEVELOPMENT. SOUTHEAST
SURFACE WINDS OVER EASTERN COLORADO TO PREVAIL BY THE THE
AFTERNOON WITH SOME HINTS OF A DENVER CYCLONE WHICH MAY INCREASE
STORM CHANCES EAST AND SOUTH OF DENVER. TEMPERATURES TO WARM IN
THE LOWER 80S ACROSS THE PLAINS. FOR SUNDAY...SOUTHWEST FLOW ALOFT
TO CONTINUE WITH WEAK UPPER TROUGH MOVING ACROSS CENTRAL PLAINS.
MODELS SHOW WEAK FRONT MOVING ACROSS THE PLAINS BY THE AFTERNOON
WITH SOME INCREASE IN LOW LEVEL MOISTURE. HOWEVER THE BEST
INSTABILITY LOOKS TO BE EAST OF COLORADO. BEST CHANCE FOR
THUNDERSTORMS TO BE ACROSS MOUNTAINS WITH A SLIGHT CHANCE OVER THE
PLAINS. HIGHS ACROSS PLAINS LOOK TO BE IN THE LOWER 80S.
FOR THE LATER DAYS...MONDAY THROUGH WEDNESDAY: MODELS SHOW UPPER
LEVEL RIDGE BUILDING ACROSS COLORADO WITH A GRADUAL DECREASE IN
SUBTROPICAL MOISTURE. THIS TO LEAD TO A DECREASING CHANCE OF
THUNDERSTORMS AND SLIGHTLY WARMER TEMPERATURES.
&&
.AVIATION...WEAK WIND SHIFT WENT BY DIA EARLIER BUT OTHERWISE A
GENERAL SOUTHEAST FLOW EXPECTED UNTIL LATER IN THE EVENING. MOST
IF NOT ALL THUNDERSTORMS SHOULD REMAIN SOUTH AND EAST OF THE
AIRPORT AS IT LOOKS NOW.
&&
.HYDROLOGY...GIVEN THE DEVELOPMENT TO OUR SOUTH AS NOTED ABOVE
WITH PUB GETTING ALMOST AN INCH OF RAIN IN A SHORT TIME THE THREAT
OF FLASH FLOODING STILL IN PLACE SO CONTINUE THE WATCH FOR THE
PALMER DIVIDE REGION.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL MIDNIGHT MDT TONIGHT FOR COZ041-046-047.
&&
$$
SHORT TERM...SZOKE
LONG TERM....D-L
AVIATION...SZOKE
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
320 PM MDT WED AUG 7 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 320 PM MDT WED AUG 7 2013
COMPLEX WEATHER PATTERN AFFECTING THE REGION THIS AFTERNOON. AT
THE SURFACE THERE IS A WEAK QUASI STATIONARY FRONTAL BOUNDARY
DRAPED NEAR THE WY BORDER. ALOFT AND STUCK IN AN UPPER LEVEL RIDGE
AXIS IS A SHORTWAVE TROUGH CENTERED IN SOUTH CENTRAL UT. WHILE THE
CENTER OF ROTATION WILL STRUGGLE TO MOVE EAST TONIGHT AS EVIDENCED
BY THE RAP MODEL...ITS TROUGH WILL ROTATE NORTHEAST INTO SOUTHERN
CO. AXIS OF GREATEST INSTABILITY...MUCAPES 1000 TO 2000 J/KG...
EXTENDS ALONG THE CO/NM BORDER AT THIS TIME AND THIS INDEED IS
WHERE THE MOST VIGOROUS CONVECTION HAS DEVELOPED. THESE STORMS
WILL MOVE NORTHEAST INTO SOUTHWEST CO AND INTO THE SAN JUAN MTNS
THROUGH EARLY EVENING. MEANWHILE...RAINFALL ASSOCIATED WITH THE
CENTER OF ROTATION ACROSS SRN UT WILL ALSO MOVE EAST. OBSERVED
RAINFALL RATES SO FAR THIS AFTERNOON HAVE BEEN 0.2 TO 0.3/HOUR IN
PARTS OF THE SAN JUANS AND IN THE CENTRAL MTNS. EXPECT EVEN HIGHER
RATES TO OCCUR WITH THE STRONG CONVECTION. SO FLASH FLOOD WATCH
LOOKS GOOD AND WILL REMAIN IN EFFECT THROUGH MIDNIGHT. THERE IS A
MID LEVEL SHEAR AXIS BASICALLY ALONG I-70 WITH DRIER AIR TO THE
NORTH. CONSEQUENTLY CONVECTION NORTH OF I-70 WILL BE LESS ROBUST.
EXPECT SHOWERS TO DIMINISH OVERNIGHT BUT LINGER OVER THE CENTRAL
AND SOUTHERN AREAS TO SOME EXTENT.
ON THURSDAY...THE SHORTWAVE SHOULD BE EAST OF THE AREA WITH THE
RIDGE AXIS AGAIN DOMINATING. HOWEVER...THERE WILL STILL BE MID TO
HIGH LEVEL MOISTURE TRAPPED UNDER THE RIDGE...SO EXPECT ISOLATED
TO SCATTERED CONVECTION DIURNAL CONVECTION WEST TO NUMEROUS STORMS
EAST...FOCUSED ON THE USUAL HIGHER TERRAIN LOCATIONS.
SLIGHTLY LESS CLOUD COVER INITIALLY ON THURSDAY WILL HELP TEMPS
RISE A LITTLE QUICKER AND HIGHER THAN TODAY...THOUGH STILL REMAIN
BELOW NORMAL.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 320 PM MDT WED AUG 7 2013
THE LARGE SCALE PATTERN CHANGES LITTLE AS A LOW PRESSURE TROUGH
CONTINUES TO SIT ALONG THE WEST COAST...AND HIGH PRESSURE REMAINS
PARKED OVER TEXAS. AFTER A BRIEF PERIOD OF NORTH/NORTHWEST FLOW
BEHIND TODAY`S DISTURBANCE...SOUTHERLY FLOW WILL QUICKLY BECOME
REESTABLISHED ON FRIDAY. HOWEVER MODELS CONTINUE TO ADVERTISE A
MODEST DROP IN MOISTURE ACROSS THE AREA. THESE SOMEWHAT DRIER
CONDITIONS WILL THEN PERSIST THROUGH THE EARLY PART OF NEXT WEEK.
PRECIPITABLE WATER WILL DROP FROM TODAY`S VALUES OF 0.6-1.0 INCH
...NORTH-SOUTH/CENTRAL TO MORE LIKE 0.4-0.6 INCH ACROSS MOST OF
THE AREA. THE LATEST MODEL RUNS HAVE DELAYED FURTHER DRYING UNTIL
AROUND MIDWEEK. BETTER SUNSHINE AND THIS MODEST AMOUNT OF MOISTURE
WILL STILL RESULT IN ISOLATED TO SCATTERED AFTERNOON SHOWER AND
THUNDERSTORM DEVELOPMENT...BUT THIS WILL GENERALLY BE TIED TO THE
HIGHER TERRAIN IN THIS DRIER ENVIRONMENT. ONE WEAK DISTURBANCE
WILL PASS ACROSS ID/WY AROUND THE TOP OF THE RIDGE ON FRIDAY FOR A
LITTLE ENHANCEMENT ACROSS THE NORTH...OTHERWISE THE SOUTH WILL BE
FAVORED.
THE 12Z GFS AND ECMWF RUNS SHOW GOOD AGREEMENT WITH THIS
PERSISTENT PATTERN...AND AS THE HIGH EVENTUALLY SHIFTS WEST INTO
SOUTHERN NM/AZ BY THE MIDDLE OF NEXT WEEK. AS THE HIGH REACHES
SOUTHERN NM...IT WILL TEND TO BLOCK THE SUBTROPICAL MOISTURE
STREAM. THEREFORE LOOK FOR ANOTHER NOTCH OF DRYING. IN SPITE OF
GOOD MODEL AGREEMENT...SUBSEQUENT MODEL RUNS HAVE SLOWED THE
DRYING TREND. THEREFORE CONFIDENCE IS NOT OVERLY HIGH.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 320 PM MDT WED AUG 7 2013
PREVAILING CONDITIONS AT TAF SITES WILL BE VFR. HOWEVER WITH THE
SLOW MOVING UPPER LEVEL WAVE ACROSS SE AZ AND S CO...SCT TO
NUMEROUS SHRA AND TSRA WILL BE OVER THE REGION THROUGH EARLY
TONIGHT...MAINLY KMTJ AND SOUTH. AREAS OF MOUNTAIN OBSCURATION IN
FOG/SHRA WILL BE EXPECTED. DRIER AIR ALONG AND NORTH OF I-70 WILL
KEEP THOSE LOCATIONS WITH RELATIVELY LOWER CHANCES OF CONVECTION.
CONDITIONS WILL IMPROVE LATE TONIGHT...WITH A FEW SHOWERS
PERSISTING OVER THE SAN JUAN MOUNTAINS INTO THURSDAY MORNING.
SHOWERS AND THUNDERSTORMS WILL REDEVELOP AFTER 18Z
THURSDAY...FAVORING THE SAN JUAN MOUNTAINS TO THE CENTRAL
CONTINENTAL DIVIDE AREA.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...FLASH FLOOD WATCH UNTIL MIDNIGHT MDT TONIGHT FOR COZ011-012-014-
017>023.
UT...FLASH FLOOD WATCH UNTIL MIDNIGHT MDT TONIGHT FOR UTZ022-028-029.
&&
$$
SHORT TERM...BWM
LONG TERM...EH
AVIATION...BWM
AREA FORECAST DISCUSSION
NWS MIAMI FL
158 AM EDT WED AUG 7 2013
.AVIATION...
WITH WEAK FLOW OVER SOUTH FLORIDA, THE SEA BREEZE SHOULD BE ABLE
TO DEVELOP AROUND MID DAY. UNTIL THEN, THE WEATHER SHOULD BE
FAIRLY QUIET, WITH VFR CONDITIONS. ONCE THE SEA BREEZE KICKS IN
AROUND MID DAY, IT WILL BEGIN TO ONCE AGAIN TRIGGER CONVECTION.
HOWEVER, IT SHOULD BE MORE INLAND THAN ON THE COAST, THUS, HAVE
KEPT VCTS OUT OF THE TAFS FOR ALL BUT KAPF TODAY. HOWEVER, DID
PLACE VCSH AS SOME SHOWERS COULD INITIALIZE NEAR THE COAST AND
MOVE INLAND BEFORE THEY DEVELOP INTO THUNDERSTORMS. WINDS TODAY
WILL BE GENERALLY SOUTHEAST AROUND 10 KTS.
&&
.PREV DISCUSSION... /ISSUED 801 PM EDT TUE AUG 6 2013/
UPDATE...
ONLY ISOLATED THUNDERSTORMS REMAIN EARLY THIS EVENING ACROSS
MAINLY INLAND BROWARD COUNTY AND LAKE OKEECHOBEE. THESE STORMS
CONTINUE TO WEAKEN AND SHOULD DISSIPATE OVER THE NEXT FEW HOURS.
WINDS SHOULD REMAIN LIGHT OVERNIGHT BEFORE TURNING MORE EASTERLY
ON WEDNESDAY THROUGH THE REMAINDER OF THE WEEK.
PREV DISCUSSION... /ISSUED 253 PM EDT TUE AUG 6 2013/
SHORT TERM (TONIGHT-THURSDAY NIGHT)...
A MID/UPPER LEVEL RIDGE CURRENTLY STRETCHES ACROSS THE SOUTHERN
STATES INTO THE ATLANTIC WITH AN INVERTED TROUGH MOVING WEST ACROSS
THE EASTERN BAHAMAS BENEATH THE RIDGE AXIS. AT THE SURFACE, A WEAK
SURFACE TROUGH EXTENDS FROM SOUTH FLORIDA INTO THE NORTHERN BAHAMAS
AND INTO THE CENTRAL ATLANTIC. THE SURFACE TROUGH IS A VERY SHALLOW
FEATURE AND THIS COMBINED WITH THE UPPER TROUGH TO THE EAST AND
RIDGE TO THE NORTH IS RESULTING IN VERY WEAK SURFACE PRESSURE
GRADIENT BECOMING NORTH TO NORTHEAST FLOW ABOVE 5K FT. THE 12Z MFL
SOUNDING CAPTURED THIS WELL AND ALSO SHOWS PWAT REMAINING AT AROUND
TWO INCHES. ALL OF THIS SPELLS CONVECTIVE DEVELOPMENT MOVING OFF TO
THE SOUTH AND THE HRRR HAS BEEN INDICATING THIS ALSO WITH GOOD
INITIAL TIMING AND LOCATION. THE SOUNDING ALSO SHOWED MID LEVEL
LAPSE RATES QUITE WEAK AT 5.8 DEGREES CELSIUS/KM AND A 500 MB
TEMPERATURE OF ONLY -5.9 WHICH IS NEARLY TWO DEGREES WARMER THAN
AVERAGE FOR EARLY AUGUST SO ONLY ISOLATED STRONG STORMS ARE EXPECTED
THIS AFTERNOON AT BEST.
THE MID LEVEL TROUGH WILL CONTINUE MOVING TO THE WEST IN THE SHORT
TERM WITH ALL GLOBAL MODELS IN VERY GOOD AGREEMENT SHIFTING IT INTO
THE CENTRAL BAHAMAS ON WEDNESDAY AND THE WESTERN BAHAMAS BY LATE
THURSDAY. AS THE TROUGH APPROACHES SOUTH FLORIDA, THE EASTERLY FLOW
WILL DEEPEN AS THE UPPER RIDGE TO THE NORTH MOVES LITTLE THROUGH
THIS PERIOD. THE ATMOSPHERIC MOISTURE PROFILE WILL CHANGE LITTLE
THROUGH WEDNESDAY AND WITH THE EAST FLOW DEEPENING, THE PRIMARY
THREAT FOR CONVECTIVE ACTIVITY WILL TEND TO BE MORNING SHOWERS ALONG
THE EAST COAST AND THEN SCATTERED SHOWERS/THUNDERSTORMS DEVELOPING
OVER THE INTERIOR DURING THE AFTERNOON AND MOVING TOWARDS THE
SOUTHWEST COAST. THE STEERING WINDS ARE ONLY EXPECTED TO BE AROUND 5
MPH SO THE THREAT WILL EXIST FOR POSSIBLE LOCALLY HEAVY RAINS IN THE
NAPLES AREA.
THERE COULD ACTUALLY BE LESS ACTIVITY ON THURSDAY AS THE TROUGH
APPROACHES WHICH PLACES SOUTH FLORIDA ON THE SUBSIDENCE SIDE. THIS
TROUGH CURRENTLY SHOWS UP VERY WELL IN WATER VAPOR IMAGERY WITH
STRONG SUBSIDENCE SHOWING UP TO ITS WEST. THE MODELS ALSO SHOW THE
LOW MAINTAINING ITS CURRENT STRENGTH SO ANOTHER REASON THERE COULD
BE LESS ACTIVITY. BY THURSDAY NIGHT, THE ATMOSPHERE WILL UNDERGO
GOOD DESTABILIZATION AS THE TROUGH MOVES INTO THE STRAITS OF
FLORIDA. THE GFS IS INDICATING 500 MB TEMPERATURES COOLING TO -11
SOUTHEAST OF KEY LARGO AND -10 OFF THE SOUTHEAST COAST. THE NAM IS A
TAD BID SLOWER WITH THE MOVEMENT BUT STILL SHOWS THIS SAME COLD POOL
ABOUT 50-100 MILES TO THE SOUTHEAST OF THE GFS POSITION. AT ANY
RATE, THIS COULD SET OFF SOME IMPRESSIVE LIGHTNING DISPLAYS TO OUR
SOUTHEAST THURSDAY EVENING AND NIGHT AS CONVECTIVE CELLS COULD
EASILY DEVELOP OVER THE ATLANTIC WATERS WITH SUCH COLD TEMPERATURES
ALOFT MOVING ACROSS THE GULF STREAM WATERS MAKING THE ENVIRONMENT
VERY UNSTABLE. BUT AS ALWAYS AS WE GET OUT WITH TIME, CONFIDENCE IS
LESS SO IT IS A WAIT AND SEE APPROACH.
LONG TERM (FRIDAY-TUESDAY)...
LATE IN THE WEEK AND INTO THE WEEKEND AND EARLY NEXT WEEK, THE
TROUGH WILL CONTINUE WESTWARD INTO THE GULF OF MEXICO ALLOWING THE
ATLANTIC RIDGE TO ALSO BUILD WEST. THIS WILL STABILIZE THE
ATMOSPHERE ONCE AGAIN AND THE GFS IS ALSO SHOWING SIGNIFICANT DRYING
TAKING PLACE WITH PWAT DROPPING WELL UNDER TWO INCHES. SO WHILE
FRIDAY COULD REMAIN QUITE ACTIVE, MUCH LESS ACTIVITY IS LIKELY AS WE
GET INTO THE WEEKEND AND CROSS OVER INTO NEXT WEEK.
MARINE...
LIGHT AND VARIABLE WIND TONIGHT WILL SLOWLY BECOME EAST BY
WEDNESDAY AND THEN STRENGTHENING LATER IN THE WEEK AS THE GRADIENT
TIGHTENS. THIS WILL BUILD SEAS OVER THE NEXT COUPLE OF DAYS BUT
REMAIN WELL BELOW ADVISORY CRITERIA.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 89 78 89 80 / 30 20 20 20
FORT LAUDERDALE 90 81 90 81 / 30 20 20 20
MIAMI 91 79 89 80 / 30 20 20 20
NAPLES 92 76 93 77 / 40 30 30 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...10/CD
AVIATION/RADAR...13/SI
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1019 PM EDT THU AUG 8 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
ISSUED AT 332 PM EDT THU AUG 8 2013
WEAK DIFFUSE FRONTAL BOUNDARY WILL SAG SOUTH THROUGH THE REGION INTO
FRIDAY AS SEVERAL SURFACE WAVES RIPPLE ALONG THE BOUNDARY. THIS WILL
KEEP SCATTERED SHOWERS AND THUNDERSTORMS ACROSS CENTRAL INDIANA INTO
FRIDAY...AND OVER SOUTHERN PORTIONS OF THE AREA INTO EARLY SATURDAY
AS THE FRONT MAKES ONLY SLOW PROGRESS SOUTH INTO THE TENNESSEE
VALLEY. HIGH PRESSURE DRIFTING THROUGH THE GREAT LAKES WILL BRING
DRIER AND SLIGHTLY COOLER WEATHER SATURDAY AND SUNDAY. A COLD FRONT
WILL PASS THROUGH THE AREA EARLY NEXT WEEK WITH RAIN...FOLLOWED BY
REINFORCING SHOT OF COOLER AIR BY MIDWEEK AS THE UPPER TROUGH
DEEPENS OVER THE EASTERN U S.
&&
.NEAR TERM /REST OF TONIGHT/...
ISSUED AT 953 PM EDT THU AUG 8 2013
SHOWERS AND THUNDERSTORMS HAVE BECOME MORE NUMEROUS LAST FEW HOURS
ACROSS OUR SOUTH AS MCV APPROACHES. RAPID REFRESH FOLLOWS THIS IDEAL
WITH NUMEROUS SHOWERS AND THUNDERSTORMS ACROSS OUR SOUTH THROUGH
ABOUT 06Z AND WITH MUCH LESS ACTIVITY AFTER THAT. ALSO CONCERNED
ABOUT HEAVY RAIN POTENTIAL NEXT SEVERAL HOURS AS PRECIPITABLE WATER
RUNNING ABOUT 2 TO 2.2 INCHES. WILL CONSIDER AREAL FLOOD ADVISORIES
IN SOME AREAS TO COVER THIS.
FARTHER NORTH...CURRENT FORECAST SEEMS TO BE ON TRACK. COLD FRONT WILL
MOVE SLOWLY SOUTH ACROSS OUR AREA OVERNIGHT. NAM SEEMS TO COOL TEMPERATURES
ACROSS OUR NORTHWEST TOO MUCH BY DAYBREAK. MADE A FEW TWEAKS IN
TEMPERATURES FROM PREVIOUS FORECAST. BUT IN MOST AREAS THEY SEEM OK.
PREVIOUS NEAR TERM DISCUSSION FOLLOWS...
MESOLOW RESIDES ACROSS NORTHERN COUNTIES WITH THE FRONTAL BOUNDARY
EXTENDING SOUTHWEST INTO EAST CENTRAL ILLINOIS. LINEAR CONVECTION
HAS DEVELOPED ALONG A DIFFUSE FRONT TO THE WEST OF THE INDY
METRO...WITH ADDITIONAL CONVECTION NOW BEGINNING TO DEVELOP IN
VICINITY OF THE BOUNDARY OVER SOUTH CENTRAL ILLINOIS. MUGGY
AFTERNOON IN PROGRESS AS TEMPS HAVE RISEN INTO THE MID 80S OVER ALL
BUT FAR NORTHERN COUNTIES.
COMPLEX AND LOW CONFIDENCE FORECAST FOR THE REST OF THE AFTERNOON
AND TONIGHT AS THE PRESENCE OF THE BOUNDARY SLOWLY SAGGING SOUTH
THROUGH THE FORECAST AREA AND THE APPROACHING REMNANT MCV NEAR KSTL
ARE LIKELY TO BE FACTORS IN CONVECTIVE COVERAGE INTO THE OVERNIGHT.
HRRR HANDLING CURRENT CONVECTIVE COVERAGE REASONABLY WELL AND WAS
USED AS A START FOR THE NEXT SEVERAL HOURS.
CURRENT MESOANALYSIS INDICATES AIRMASS HAS SUFFICIENTLY DESTABILIZED
ALONG AND IMMEDIATELY AHEAD OF THE BOUNDARY. MUCH OF THE CONVECTION
HAS WEAKENED WITHIN THE VICINITY OF THE WELL DEFINED MCV OVER
EASTERN MISSOURI. HOWEVER AS THIS FEATURE CONTINUES TO APPROACH
CENTRAL INDIANA OVER THE NEXT SEVERAL HOURS AND INTERACTS WITH THE
UNSTABLE AND VERY MOIST AIRMASS OVER THE REGION...EXPECT AN INCREASE
IN CONVECTIVE COVERAGE INTO THE EVENING...LIKELY CONTINUING
OVERNIGHT AS THE MCV MOVES THROUGH THE REGION. BOTH THE RAP AND 12Z
GFS HINT AT THE LOW LEVEL JET REESTABLISHING ALONG THE OHIO RIVER
TONIGHT...WITH A LOW LEVEL BAROCLINIC ZONE SETTING UP ACROSS
SOUTHERN PORTIONS OF THE FORECAST AREA. THINK ULTIMATELY SHOULD THIS
COME TO PASS...THE HEAVIEST RAINFALL WILL SET UP OVER SOUTHERN
COUNTIES OVERNIGHT AND WILL CARRY HIGHEST POPS IN THESE AREAS.
IMPRESSIVE PRECIP WATER VALUES IN EXCESS OF 2 INCHES COMBINED WITH
STORM MOTIONS UNDER 10KTS AND STEERING CURRENTS PARALLEL TO THE
BOUNDARY ARE SUPPORTIVE OF TORRENTIAL RAINFALL...BACKBUILDING AND
TRAINING ECHOES AND POTENTIAL FOR LOCALIZED FLOODING. WITH 1 HR/3 HR
FLASH FLOOD GUIDANCE VALUES IN EXCESS OF 2 INCHES/2.5-3.5 INCHES AND
UNCERTAINTY IN HOW EXTENSIVE THE PRECIP COVERAGE BECOMES...HAVE NO
PLANS TO ISSUE A FLASH FLOOD WATCH AT THIS TIME.
TEMPS...WARMER MAVMOS LOOKS REASONABLE CONSIDERING HIGH LOW LEVEL
MOISTURE PRESENT OVER THE REGION. NAM APPEARS TO BE ADVECTING DRIER
AIR INTO THE REGION TOO AGGRESSIVELY EARLY FRIDAY AND THIS IS LIKELY
IMPACTING MET GUIDANCE LOWS.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
ISSUED AT 332 PM EDT THU AUG 8 2013
FORECAST CHALLENGES REMAIN ON PRECIP CHANCES INTO EARLY SATURDAY AS
THE FRONTAL BOUNDARY MAKES ONLY SLOW PROGRESS SOUTH.
REMNANT MCV AND A WEAK SURFACE WAVE WILL BE SHIFTING EAST OF THE
REGION BY 12Z FRIDAY. FOCUS FOR ADDITIONAL CONVECTIVE DEVELOPMENT
WILL BE SOUTH OF I-70 AS THE BOUNDARY SETTLES OVER SOUTHERN INDIANA
BY FRIDAY AFTERNOON. WILL ONCE AGAIN FOCUS HIGHEST POPS OVER
SOUTHERN COUNTIES WITH LOW CHANCE POPS NORTH OF I-70 AS SLIGHTLY
DRIER AIR BEGINS TO EXPAND SOUTH FROM THE GREAT LAKES. THE BOUNDARY
WILL CONTINUE TO SHIFT SOUTH THROUGH KENTUCKY ON FRIDAY NIGHT AS AN
UPPER LOW PIVOTS SOUTH OF JAMES BAY AND INTRODUCES A BROAD UPPER
LEVEL TROUGH OVER THE EASTERN U S. WILL HANG ONTO LOW CHANCE POPS
OVER SOUTHERN COUNTIES FRIDAY NIGHT AND EARLY SATURDAY DUE TO THE
CLOSE PROXIMITY OF THE BOUNDARY...BUT OVERALL TREND INTO SATURDAY
SHOULD BE TOWARDS DRIER AND SLIGHTLY COOLER AIR EXPANDING INTO THE
FORECAST AREA AS THE DEEPER MOISTURE IS PUSHED SOUTH.
SURFACE HIGH PRESSURE WILL BUILD ACROSS THE LOWER GREAT LAKES
SATURDAY AFTERNOON THROUGH SUNDAY WITH DRY WEATHER. LOW LEVEL
MOISTURE ATTEMPTS TO IMMEDIATELY RETURN BACK NORTH INTO THE OHIO
VALLEY SUNDAY AFTERNOON AS THE HIGH SHIFTS AWAY TO THE EAST. HAVE
KEPT DRY CONDITIONS THROUGH 00Z MONDAY AS LITTLE FORCING ALOFT
PRESENT...ALTHOUGH WILL HAVE TO MONITOR FOR ISOLATED SHOWERS OVER
THE LOWER WABASH VALLEY AS INSTABILITY AXIS WILL BE CLOSE BY ACROSS
THE LOWER OHIO VALLEY.
TEMPS...MOS GUIDANCE IN GENERAL WORKS WELL CONSIDERING LOW LEVEL
THERMALS THROUGHOUT THE PERIOD. HIGH TEMPS FRIDAY AND SATURDAY WILL
BE HIGHLY DEPENDENT ON CLOUD COVER...BUT GENERALLY LOOKING AT LOW TO
MID 80S BOTH DAYS...SLIGHTLY COOLER WHERE RAIN/CLOUDS IMPACT. CORE
OF THE COOLER AIR ASSOCIATED WITH THE UPPER TROUGH LIKELY DELAYED TO
SUNDAY AS 850MB TEMPS FALL TO AROUND 11C. LOCATIONS SUNDAY SHOULD
REMAIN IN THE UPPER 70S AND LOWER 80S.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
ISSUED AT 229 PM EDT THU AUG 8 2013
MODELS ARE SIMILAR ENOUGH THAT THE ALLBLEND INITIALIZATION CAN BE
USED FOR MOST ITEMS IN THE LONG TERM.
UPPER TROUGH WILL DEEPEN ACROSS THE AREA IN THE EXTENDED. THIS WILL
KEEP CENTRAL INDIANA IN COOLER NORTHWEST FLOW. TEMPERATURES WILL
REMAIN BELOW AVERAGE THROUGH THE PERIOD.
A COLD FRONT WILL WORK ITS WAY SOUTH MONDAY INTO TUESDAY BRINGING
THE COOLER AIR TO THE AREA. MODELS AND SOME ENSEMBLES ARE SHOWING
CHANCES FOR RAIN LINGERING INTO TUESDAY WITH SOME TIMING DIFFERENCES
BETWEEN THEM. GIVEN THE UNCERTAINTIES INVOLVED WILL GO WITH
ALLBLEND/S CHANCES FOR RAIN MONDAY INTO TUESDAY...BUT AT THE MOMENT
&&
.AVIATION /DISCUSSION FOR THE 09/0300Z TAF UPDATE/...
ISSUED AT 1013 PM EDT THU AUG 8 2013
UPDATE...
MVFR/IFR CONDITIONS WILL AFFECT KHUF AND KBMG THROUGH FRI 04Z DUE
TO PERSISTENT SHOWERS AND ISOLATED THUNDERSTORMS MOVING THROUGH THE
AREA. ELSEWHERE...VFR CONDITIONS ARE HOLDING STEADY AT KLAF AND
KIND...BUT THOSE SHOULD DETERIORATE TO MVFR LATER TONIGHT AS
CEILINGS FALL AND FOG FORMS.
PREVIOUS DISCUSSION...
A WEAK FRONTAL BOUNDARY ACROSS SOUTHEAST INDIANA IS CURRENTLY
GENERATING SCATTERED SHOWERS AND THUNDERSTORMS OVER PORTIONS OF
THE AREA. HOWEVER...NONE OF THE CONVECTION SEEMS TO BE HOLDING ANY
ORGANIZATION FOR LONG...SO WILL LEAVE OUT OF TAFS AT THIS TIME AND
COVER WITH ANY UPDATES THAT MAY BE NEEDED. OUTSIDE OF SHOWERS AND
STORMS...CONDITIONS ARE GENERALLY VFR WITH QUICK DETERIORATION TO
MVFR/IFR IN HEAVY DOWNPOURS.
TONIGHT...MVFR VIS/CEILINGS CAN BE EXPECTED WITH RELATIVELY MOIST
AIRMASS IN PLACE. AS AFOREMENTIONED FRONTAL BOUNDARY SHIFTS
FURTHER SOUTH TOMORROW...DRIER AIR WILL WORK INTO TAF SITES...BRINGING
VFR CONDITIONS BY EARLY AFTERNOON. WINDS WILL BE NORTHERLY AT 2 TO
8 KTS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN/JH
SHORT TERM...RYAN
LONG TERM....50
AVIATION...TDUD
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
953 PM EDT THU AUG 8 2013
.UPDATE...
NEAR TERM FOR THE REST OF TONIGHT HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 332 PM EDT THU AUG 8 2013
WEAK DIFFUSE FRONTAL BOUNDARY WILL SAG SOUTH THROUGH THE REGION INTO
FRIDAY AS SEVERAL SURFACE WAVES RIPPLE ALONG THE BOUNDARY. THIS WILL
KEEP SCATTERED SHOWERS AND THUNDERSTORMS ACROSS CENTRAL INDIANA INTO
FRIDAY...AND OVER SOUTHERN PORTIONS OF THE AREA INTO EARLY SATURDAY
AS THE FRONT MAKES ONLY SLOW PROGRESS SOUTH INTO THE TENNESSEE
VALLEY. HIGH PRESSURE DRIFTING THROUGH THE GREAT LAKES WILL BRING
DRIER AND SLIGHTLY COOLER WEATHER SATURDAY AND SUNDAY. A COLD FRONT
WILL PASS THROUGH THE AREA EARLY NEXT WEEK WITH RAIN...FOLLOWED BY
REINFORCING SHOT OF COOLER AIR BY MIDWEEK AS THE UPPER TROUGH
DEEPENS OVER THE EASTERN U S.
&&
.NEAR TERM /REST OF TONIGHT/...
ISSUED AT 953 PM EDT THU AUG 8 2013
SHOWERS AND THUNDERSTORMS HAVE BECOME MORE NUMEROUS LAST FEW HOURS
ACROSS OUR SOUTH AS MCV APPROACHES. RAPID REFRESH FOLLOWS THIS IDEAL
WITH NUMEROUS SHOWERS AND THUNDERSTORMS ACROSS OUR SOUTH THROUGH
ABOUT 06Z AND WITH MUCH LESS ACTIVITY AFTER THAT. ALSO CONCERNED
ABOUT HEAVY RAIN POTENTIAL NEXT SEVERAL HOURS AS PRECIPITABLE WATER
RUNNING ABOUT 2 TO 2.2 INCHES. WILL CONSIDER AREAL FLOOD ADVISORIES
IN SOME AREAS TO COVER THIS.
FARTHER NORTH...CURRENT FORECAST SEEMS TO BE ON TRACK. COLD FRONT WILL
MOVE SLOWLY SOUTH ACROSS OUR AREA OVERNIGHT. NAM SEEMS TO COOL TEMPERATURES
ACROSS OUR NORTHWEST TOO MUCH BY DAYBREAK. MADE A FEW TWEAKS IN
TEMPERATURES FROM PREVIOUS FORECAST. BUT IN MOST AREAS THEY SEEM OK.
PREVIOUS NEAR TERM DISCUSSION FOLLOWS...
MESOLOW RESIDES ACROSS NORTHERN COUNTIES WITH THE FRONTAL BOUNDARY
EXTENDING SOUTHWEST INTO EAST CENTRAL ILLINOIS. LINEAR CONVECTION
HAS DEVELOPED ALONG A DIFFUSE FRONT TO THE WEST OF THE INDY
METRO...WITH ADDITIONAL CONVECTION NOW BEGINNING TO DEVELOP IN
VICINITY OF THE BOUNDARY OVER SOUTH CENTRAL ILLINOIS. MUGGY
AFTERNOON IN PROGRESS AS TEMPS HAVE RISEN INTO THE MID 80S OVER ALL
BUT FAR NORTHERN COUNTIES.
COMPLEX AND LOW CONFIDENCE FORECAST FOR THE REST OF THE AFTERNOON
AND TONIGHT AS THE PRESENCE OF THE BOUNDARY SLOWLY SAGGING SOUTH
THROUGH THE FORECAST AREA AND THE APPROACHING REMNANT MCV NEAR KSTL
ARE LIKELY TO BE FACTORS IN CONVECTIVE COVERAGE INTO THE OVERNIGHT.
HRRR HANDLING CURRENT CONVECTIVE COVERAGE REASONABLY WELL AND WAS
USED AS A START FOR THE NEXT SEVERAL HOURS.
CURRENT MESOANALYSIS INDICATES AIRMASS HAS SUFFICIENTLY DESTABILIZED
ALONG AND IMMEDIATELY AHEAD OF THE BOUNDARY. MUCH OF THE CONVECTION
HAS WEAKENED WITHIN THE VICINITY OF THE WELL DEFINED MCV OVER
EASTERN MISSOURI. HOWEVER AS THIS FEATURE CONTINUES TO APPROACH
CENTRAL INDIANA OVER THE NEXT SEVERAL HOURS AND INTERACTS WITH THE
UNSTABLE AND VERY MOIST AIRMASS OVER THE REGION...EXPECT AN INCREASE
IN CONVECTIVE COVERAGE INTO THE EVENING...LIKELY CONTINUING
OVERNIGHT AS THE MCV MOVES THROUGH THE REGION. BOTH THE RAP AND 12Z
GFS HINT AT THE LOW LEVEL JET REESTABLISHING ALONG THE OHIO RIVER
TONIGHT...WITH A LOW LEVEL BAROCLINIC ZONE SETTING UP ACROSS
SOUTHERN PORTIONS OF THE FORECAST AREA. THINK ULTIMATELY SHOULD THIS
COME TO PASS...THE HEAVIEST RAINFALL WILL SET UP OVER SOUTHERN
COUNTIES OVERNIGHT AND WILL CARRY HIGHEST POPS IN THESE AREAS.
IMPRESSIVE PRECIP WATER VALUES IN EXCESS OF 2 INCHES COMBINED WITH
STORM MOTIONS UNDER 10KTS AND STEERING CURRENTS PARALLEL TO THE
BOUNDARY ARE SUPPORTIVE OF TORRENTIAL RAINFALL...BACKBUILDING AND
TRAINING ECHOES AND POTENTIAL FOR LOCALIZED FLOODING. WITH 1 HR/3 HR
FLASH FLOOD GUIDANCE VALUES IN EXCESS OF 2 INCHES/2.5-3.5 INCHES AND
UNCERTAINTY IN HOW EXTENSIVE THE PRECIP COVERAGE BECOMES...HAVE NO
PLANS TO ISSUE A FLASH FLOOD WATCH AT THIS TIME.
TEMPS...WARMER MAVMOS LOOKS REASONABLE CONSIDERING HIGH LOW LEVEL
MOISTURE PRESENT OVER THE REGION. NAM APPEARS TO BE ADVECTING DRIER
AIR INTO THE REGION TOO AGGRESSIVELY EARLY FRIDAY AND THIS IS LIKELY
IMPACTING MET GUIDANCE LOWS.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
ISSUED AT 332 PM EDT THU AUG 8 2013
FORECAST CHALLENGES REMAIN ON PRECIP CHANCES INTO EARLY SATURDAY AS
THE FRONTAL BOUNDARY MAKES ONLY SLOW PROGRESS SOUTH.
REMNANT MCV AND A WEAK SURFACE WAVE WILL BE SHIFTING EAST OF THE
REGION BY 12Z FRIDAY. FOCUS FOR ADDITIONAL CONVECTIVE DEVELOPMENT
WILL BE SOUTH OF I-70 AS THE BOUNDARY SETTLES OVER SOUTHERN INDIANA
BY FRIDAY AFTERNOON. WILL ONCE AGAIN FOCUS HIGHEST POPS OVER
SOUTHERN COUNTIES WITH LOW CHANCE POPS NORTH OF I-70 AS SLIGHTLY
DRIER AIR BEGINS TO EXPAND SOUTH FROM THE GREAT LAKES. THE BOUNDARY
WILL CONTINUE TO SHIFT SOUTH THROUGH KENTUCKY ON FRIDAY NIGHT AS AN
UPPER LOW PIVOTS SOUTH OF JAMES BAY AND INTRODUCES A BROAD UPPER
LEVEL TROUGH OVER THE EASTERN U S. WILL HANG ONTO LOW CHANCE POPS
OVER SOUTHERN COUNTIES FRIDAY NIGHT AND EARLY SATURDAY DUE TO THE
CLOSE PROXIMITY OF THE BOUNDARY...BUT OVERALL TREND INTO SATURDAY
SHOULD BE TOWARDS DRIER AND SLIGHTLY COOLER AIR EXPANDING INTO THE
FORECAST AREA AS THE DEEPER MOISTURE IS PUSHED SOUTH.
SURFACE HIGH PRESSURE WILL BUILD ACROSS THE LOWER GREAT LAKES
SATURDAY AFTERNOON THROUGH SUNDAY WITH DRY WEATHER. LOW LEVEL
MOISTURE ATTEMPTS TO IMMEDIATELY RETURN BACK NORTH INTO THE OHIO
VALLEY SUNDAY AFTERNOON AS THE HIGH SHIFTS AWAY TO THE EAST. HAVE
KEPT DRY CONDITIONS THROUGH 00Z MONDAY AS LITTLE FORCING ALOFT
PRESENT...ALTHOUGH WILL HAVE TO MONITOR FOR ISOLATED SHOWERS OVER
THE LOWER WABASH VALLEY AS INSTABILITY AXIS WILL BE CLOSE BY ACROSS
THE LOWER OHIO VALLEY.
TEMPS...MOS GUIDANCE IN GENERAL WORKS WELL CONSIDERING LOW LEVEL
THERMALS THROUGHOUT THE PERIOD. HIGH TEMPS FRIDAY AND SATURDAY WILL
BE HIGHLY DEPENDENT ON CLOUD COVER...BUT GENERALLY LOOKING AT LOW TO
MID 80S BOTH DAYS...SLIGHTLY COOLER WHERE RAIN/CLOUDS IMPACT. CORE
OF THE COOLER AIR ASSOCIATED WITH THE UPPER TROUGH LIKELY DELAYED TO
SUNDAY AS 850MB TEMPS FALL TO AROUND 11C. LOCATIONS SUNDAY SHOULD
REMAIN IN THE UPPER 70S AND LOWER 80S.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
ISSUED AT 229 PM EDT THU AUG 8 2013
MODELS ARE SIMILAR ENOUGH THAT THE ALLBLEND INITIALIZATION CAN BE
USED FOR MOST ITEMS IN THE LONG TERM.
UPPER TROUGH WILL DEEPEN ACROSS THE AREA IN THE EXTENDED. THIS WILL
KEEP CENTRAL INDIANA IN COOLER NORTHWEST FLOW. TEMPERATURES WILL
REMAIN BELOW AVERAGE THROUGH THE PERIOD.
A COLD FRONT WILL WORK ITS WAY SOUTH MONDAY INTO TUESDAY BRINGING
THE COOLER AIR TO THE AREA. MODELS AND SOME ENSEMBLES ARE SHOWING
CHANCES FOR RAIN LINGERING INTO TUESDAY WITH SOME TIMING DIFFERENCES
BETWEEN THEM. GIVEN THE UNCERTAINTIES INVOLVED WILL GO WITH
ALLBLEND/S CHANCES FOR RAIN MONDAY INTO TUESDAY...BUT AT THE MOMENT
&&
.AVIATION /DISCUSSION FOR THE 09/0000Z TAF ISSUANCE/...
ISSUED AT 733 PM EDT THU AUG 8 2013
A WEAK FRONTAL BOUNDARY ACROSS SOUTHEAST INDIANA IS CURRENTLY
GENERATING SCATTERED SHOWERS AND THUNDERSTORMS OVER PORTIONS OF
THE AREA. HOWEVER...NONE OF THE CONVECTION SEEMS TO BE HOLDING ANY
ORGANIZATION FOR LONG...SO WILL LEAVE OUT OF TAFS AT THIS TIME AND
COVER WITH ANY UPDATES THAT MAY BE NEEDED. OUTSIDE OF SHOWERS AND
STORMS...CONDITIONS ARE GENERALLY VFR WITH QUICK DETERIORATION TO
MVFR/IFR IN HEAVY DOWNPOURS.
TONIGHT...MVFR VIS/CEILINGS CAN BE EXPECTED WITH RELATIVELY MOIST
AIRMASS IN PLACE. AS AFOREMENTIONED FRONTAL BOUNDARY SHIFTS
FURTHER SOUTH TOMORROW...DRIER AIR WILL WORK INTO TAF SITES...BRINGING
VFR CONDITIONS BY EARLY AFTERNOON. WINDS WILL BE NORTHERLY AT 2 TO
8 KTS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN/JH
SHORT TERM...RYAN
LONG TERM....50
AVIATION...TDUD
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
745 PM EDT THU AUG 8 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
ISSUED AT 332 PM EDT THU AUG 8 2013
WEAK DIFFUSE FRONTAL BOUNDARY WILL SAG SOUTH THROUGH THE REGION INTO
FRIDAY AS SEVERAL SURFACE WAVES RIPPLE ALONG THE BOUNDARY. THIS WILL
KEEP SCATTERED SHOWERS AND THUNDERSTORMS ACROSS CENTRAL INDIANA INTO
FRIDAY...AND OVER SOUTHERN PORTIONS OF THE AREA INTO EARLY SATURDAY
AS THE FRONT MAKES ONLY SLOW PROGRESS SOUTH INTO THE TENNESSEE
VALLEY. HIGH PRESSURE DRIFTING THROUGH THE GREAT LAKES WILL BRING
DRIER AND SLIGHTLY COOLER WEATHER SATURDAY AND SUNDAY. A COLD FRONT
WILL PASS THROUGH THE AREA EARLY NEXT WEEK WITH RAIN...FOLLOWED BY
REINFORCING SHOT OF COOLER AIR BY MIDWEEK AS THE UPPER TROUGH
DEEPENS OVER THE EASTERN U S.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 332 PM EDT THU AUG 8 2013
MESOLOW RESIDES ACROSS NORTHERN COUNTIES WITH THE FRONTAL BOUNDARY
EXTENDING SOUTHWEST INTO EAST CENTRAL ILLINOIS. LINEAR CONVECTION
HAS DEVELOPED ALONG A DIFFUSE FRONT TO THE WEST OF THE INDY
METRO...WITH ADDITIONAL CONVECTION NOW BEGINNING TO DEVELOP IN
VICINITY OF THE BOUNDARY OVER SOUTH CENTRAL ILLINOIS. MUGGY
AFTERNOON IN PROGRESS AS TEMPS HAVE RISEN INTO THE MID 80S OVER ALL
BUT FAR NORTHERN COUNTIES.
COMPLEX AND LOW CONFIDENCE FORECAST FOR THE REST OF THE AFTERNOON
AND TONIGHT AS THE PRESENCE OF THE BOUNDARY SLOWLY SAGGING SOUTH
THROUGH THE FORECAST AREA AND THE APPROACHING REMNANT MCV NEAR KSTL
ARE LIKELY TO BE FACTORS IN CONVECTIVE COVERAGE INTO THE OVERNIGHT.
HRRR HANDLING CURRENT CONVECTIVE COVERAGE REASONABLY WELL AND WAS
USED AS A START FOR THE NEXT SEVERAL HOURS.
CURRENT MESOANALYSIS INDICATES AIRMASS HAS SUFFICIENTLY DESTABILIZED
ALONG AND IMMEDIATELY AHEAD OF THE BOUNDARY. MUCH OF THE CONVECTION
HAS WEAKENED WITHIN THE VICINITY OF THE WELL DEFINED MCV OVER
EASTERN MISSOURI. HOWEVER AS THIS FEATURE CONTINUES TO APPROACH
CENTRAL INDIANA OVER THE NEXT SEVERAL HOURS AND INTERACTS WITH THE
UNSTABLE AND VERY MOIST AIRMASS OVER THE REGION...EXPECT AN INCREASE
IN CONVECTIVE COVERAGE INTO THE EVENING...LIKELY CONTINUING
OVERNIGHT AS THE MCV MOVES THROUGH THE REGION. BOTH THE RAP AND 12Z
GFS HINT AT THE LOW LEVEL JET REESTABLISHING ALONG THE OHIO RIVER
TONIGHT...WITH A LOW LEVEL BAROCLINIC ZONE SETTING UP ACROSS
SOUTHERN PORTIONS OF THE FORECAST AREA. THINK ULTIMATELY SHOULD THIS
COME TO PASS...THE HEAVIEST RAINFALL WILL SET UP OVER SOUTHERN
COUNTIES OVERNIGHT AND WILL CARRY HIGHEST POPS IN THESE AREAS.
IMPRESSIVE PRECIP WATER VALUES IN EXCESS OF 2 INCHES COMBINED WITH
STORM MOTIONS UNDER 10KTS AND STEERING CURRENTS PARALLEL TO THE
BOUNDARY ARE SUPPORTIVE OF TORRENTIAL RAINFALL...BACKBUILDING AND
TRAINING ECHOES AND POTENTIAL FOR LOCALIZED FLOODING. WITH 1 HR/3 HR
FLASH FLOOD GUIDANCE VALUES IN EXCESS OF 2 INCHES/2.5-3.5 INCHES AND
UNCERTAINTY IN HOW EXTENSIVE THE PRECIP COVERAGE BECOMES...HAVE NO
PLANS TO ISSUE A FLASH FLOOD WATCH AT THIS TIME.
TEMPS...WARMER MAVMOS LOOKS REASONABLE CONSIDERING HIGH LOW LEVEL
MOISTURE PRESENT OVER THE REGION. NAM APPEARS TO BE ADVECTING DRIER
AIR INTO THE REGION TOO AGGRESSIVELY EARLY FRIDAY AND THIS IS LIKELY
IMPACTING MET GUIDANCE LOWS.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
ISSUED AT 332 PM EDT THU AUG 8 2013
FORECAST CHALLENGES REMAIN ON PRECIP CHANCES INTO EARLY SATURDAY AS
THE FRONTAL BOUNDARY MAKES ONLY SLOW PROGRESS SOUTH.
REMNANT MCV AND A WEAK SURFACE WAVE WILL BE SHIFTING EAST OF THE
REGION BY 12Z FRIDAY. FOCUS FOR ADDITIONAL CONVECTIVE DEVELOPMENT
WILL BE SOUTH OF I-70 AS THE BOUNDARY SETTLES OVER SOUTHERN INDIANA
BY FRIDAY AFTERNOON. WILL ONCE AGAIN FOCUS HIGHEST POPS OVER
SOUTHERN COUNTIES WITH LOW CHANCE POPS NORTH OF I-70 AS SLIGHTLY
DRIER AIR BEGINS TO EXPAND SOUTH FROM THE GREAT LAKES. THE BOUNDARY
WILL CONTINUE TO SHIFT SOUTH THROUGH KENTUCKY ON FRIDAY NIGHT AS AN
UPPER LOW PIVOTS SOUTH OF JAMES BAY AND INTRODUCES A BROAD UPPER
LEVEL TROUGH OVER THE EASTERN U S. WILL HANG ONTO LOW CHANCE POPS
OVER SOUTHERN COUNTIES FRIDAY NIGHT AND EARLY SATURDAY DUE TO THE
CLOSE PROXIMITY OF THE BOUNDARY...BUT OVERALL TREND INTO SATURDAY
SHOULD BE TOWARDS DRIER AND SLIGHTLY COOLER AIR EXPANDING INTO THE
FORECAST AREA AS THE DEEPER MOISTURE IS PUSHED SOUTH.
SURFACE HIGH PRESSURE WILL BUILD ACROSS THE LOWER GREAT LAKES
SATURDAY AFTERNOON THROUGH SUNDAY WITH DRY WEATHER. LOW LEVEL
MOISTURE ATTEMPTS TO IMMEDIATELY RETURN BACK NORTH INTO THE OHIO
VALLEY SUNDAY AFTERNOON AS THE HIGH SHIFTS AWAY TO THE EAST. HAVE
KEPT DRY CONDITIONS THROUGH 00Z MONDAY AS LITTLE FORCING ALOFT
PRESENT...ALTHOUGH WILL HAVE TO MONITOR FOR ISOLATED SHOWERS OVER
THE LOWER WABASH VALLEY AS INSTABILITY AXIS WILL BE CLOSE BY ACROSS
THE LOWER OHIO VALLEY.
TEMPS...MOS GUIDANCE IN GENERAL WORKS WELL CONSIDERING LOW LEVEL
THERMALS THROUGHOUT THE PERIOD. HIGH TEMPS FRIDAY AND SATURDAY WILL
BE HIGHLY DEPENDENT ON CLOUD COVER...BUT GENERALLY LOOKING AT LOW TO
MID 80S BOTH DAYS...SLIGHTLY COOLER WHERE RAIN/CLOUDS IMPACT. CORE
OF THE COOLER AIR ASSOCIATED WITH THE UPPER TROUGH LIKELY DELAYED TO
SUNDAY AS 850MB TEMPS FALL TO AROUND 11C. LOCATIONS SUNDAY SHOULD
REMAIN IN THE UPPER 70S AND LOWER 80S.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
ISSUED AT 229 PM EDT THU AUG 8 2013
MODELS ARE SIMILAR ENOUGH THAT THE ALLBLEND INITIALIZATION CAN BE
USED FOR MOST ITEMS IN THE LONG TERM.
UPPER TROUGH WILL DEEPEN ACROSS THE AREA IN THE EXTENDED. THIS WILL
KEEP CENTRAL INDIANA IN COOLER NORTHWEST FLOW. TEMPERATURES WILL
REMAIN BELOW AVERAGE THROUGH THE PERIOD.
A COLD FRONT WILL WORK ITS WAY SOUTH MONDAY INTO TUESDAY BRINGING
THE COOLER AIR TO THE AREA. MODELS AND SOME ENSEMBLES ARE SHOWING
CHANCES FOR RAIN LINGERING INTO TUESDAY WITH SOME TIMING DIFFERENCES
BETWEEN THEM. GIVEN THE UNCERTAINTIES INVOLVED WILL GO WITH
ALLBLEND/S CHANCES FOR RAIN MONDAY INTO TUESDAY...BUT AT THE MOMENT
&&
.AVIATION /DISCUSSION FOR THE 09/0000Z TAF ISSUANCE/...
ISSUED AT 733 PM EDT THU AUG 8 2013
A WEAK FRONTAL BOUNDARY ACROSS SOUTHEAST INDIANA IS CURRENTLY
GENERATING SCATTERED SHOWERS AND THUNDERSTORMS OVER PORTIONS OF
THE AREA. HOWEVER...NONE OF THE CONVECTION SEEMS TO BE HOLDING ANY
ORGANIZATION FOR LONG...SO WILL LEAVE OUT OF TAFS AT THIS TIME AND
COVER WITH ANY UPDATES THAT MAY BE NEEDED. OUTSIDE OF SHOWERS AND
STORMS...CONDITIONS ARE GENERALLY VFR WITH QUICK DETERIORATION TO
MVFR/IFR IN HEAVY DOWNPOURS.
TONIGHT...MVFR VIS/CEILINGS CAN BE EXPECTED WITH RELATIVELY MOIST
AIRMASS IN PLACE. AS AFOREMENTIONED FRONTAL BOUNDARY SHIFTS
FURTHER SOUTH TOMORROW...DRIER AIR WILL WORK INTO TAF SITES...BRINGING
VFR CONDITIONS BY EARLY AFTERNOON. WINDS WILL BE NORTHERLY AT 2 TO
8 KTS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM....50
AVIATION...TDUD
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
106 PM CDT WED AUG 7 2013
.UPDATE...
ISSUED AT 105 PM CDT WED AUG 7 2013
COLD FRONT CONTINUES TO SAG TO THE SOUTHEAST AND IN THE DVN CWA
EXTENDS FROM PUTNAM COUNTY TO HANCOCK COUNTY. A FEW SHOWERS AND
ISOLATED THUNDERSTORMS WILL CONTINUE ALONG AND AHEAD OF THE FRONT
WHICH SHOULD EXIT THE CWA EARLY THIS AFTERNOON.
ELSEWHERE...A BAND OF LOW CLOUDS WAS DROPPING SOUTHEAST INTO OUR
FAR NW CWA BUT WAS ERODING/THINNING ON THE SOUTH EDGE.
TEMPERATURES HAVE REACHED THEIR PEAK AND ARE EXPECTED TO STEADY OUT.
DEWPOINTS WILL ALSO GRADUALLY LOWER THROUGH THE AFTERNOON WITH
NORTHWEST TO NORTH WINDS ADVECTING SOMEWHAT DRIER AIR INTO THE CWA.
UPDATE ISSUED AT 1020 AM CDT WED AUG 7 2013
A FEW THUNDERSTORMS HAVE DEVELOPED ALONG THE COLD FRONT FROM JUST
NORTHWEST OF MACOMB TO NEAR KEWANEE AND WERE MOVING EAST/NORTHEAST.
SOME OF THE STORMS WILL PRODUCE BRIEF HEAVY RAINFALL. THE FRONT
WILL CONTINUE TO SAG TO THE SOUTHEAST OF THE CWA BY NOON OR 1 PM.
THE HRRR MESO MODEL INDICATES THE FRONT BECOMING MORE ACTIVE BY
EARLY THIS AFTERNOON BUT BY THEN THE FRONT SHOULD BE SOUTHEAST OF
THE DVN CWA.
OTHERWISE...BEHIND THE FRONT WINDS WILL TURN NORTHWEST TO NORTH
WITH GRADUALLY LOWERING DEW POINTS. CANADIAN HIGH WILL BUILD INTO
THE REGION TONIGHT AND THURSDAY WITH MUCH MORE COMFORTABLE TEMPERATURES
AND HUMIDITY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 322 AM CDT WED AUG 7 2013
WESTERN GRT LKS FRONTAL SYSTEM TO CONTINUE TO SWEEP THROUGH THE
AREA THIS MORNING AND WILL WALK OUT ANY LINGERING CONVECTION/STORM
CLUSTERS THROUGH 14Z TO 16Z...MAY DECAY BEFORE THEN LIKE LATEST
HIRES MODEL RUNS SUGGEST. DESPITE FROPA...SOME LAG IN LLVL COOLER
AIR ADVECTION AND EXPECT TEMPS TO WARM INTO THE LOW TO MID 80S
IN THE SOUTHEASTERN HALF OF THE DVN CWA...UPPER 70S IN THE
NORTHWESTERN FCST AREA. THESE TEMPS BANKING ON CONVECTIVE DEBRIS
ERODING DIURNALLY. A BOUT OF PASSING SFC RIDGING WILL MAKE FOR A
MAINLY CLEAR SKY AND COOLER TEMPS TONIGHT WITH SOME 50S OCCURRING
NORTH OF I80. VALLEY FOG POSSIBLE.
.LONG TERM...(THURSDAY THROUGH NEXT TUESDAY)
ISSUED AT 322 AM CDT WED AUG 7 2013
GENERALLY BELOW NORMAL TEMP REGIME CONTINUES. MAIN STORY AT THE
END OF THE WEEK WILL BE ACTIVE GRT BSN AND SOUTHERN STREAM FLOWS
LOADED WITH MONSOONAL MOISTURE AND IF SOME OF IT CAN MAKE IT THIS
FAR NORTH. LATEST MODEL TRENDS CONTINUE TO SHOW SOME PHASING
POTENTIAL WITH NORTHERN PLAINS/UPPER MIDWEST TROFFINESS WHICH
WOULD INDUCE SOME LLVL CYCLOGENESIS ACRS THE SOUTHERN PLAINS OVER
TO THE MID MS RVR VALLEY. TIMING OF THIS PROCESS AND HOW FAR NORTH
IT CAN MAKE IT STILL UNCERTAIN WITH MODEL VARIABILITY...BUT SIGNALS
ARE THERE THAT AT LEAST THE SOUTHERN THIRD TO HALF OF THE CWA MAY
GET IN ON SOME OVERRUNNING PRECIP/SOME POTENTIALLY DECENT SOAKING RAINS/
AT WEEKS END. THE 00Z GFS AND UKMET TARGET LATE THU NIGHT INTO
FRIDAY...WHILE THE 00Z ECMWF IS POINTING AT FRI NIGHT AND NOT AS
FAR NORTH AS THE PREVIOUS MENTIONED MODELS WITH IT/S PRECIP SWATH.
MAY TREND TOWARD THE UKMET AND GFS WITH POPS INCREASING IN THE
SOUTH THU NIGHT INTO FRI FOR NOW. BUST POTENTIAL FOR ADVERTISED
TEMPS TO BE TOO WARM IN THE SOUTH HALF IF THIS MATERIALIZES
BECAUSE OF PRECIP AND CLOUD COVER ESPECIALLY ON FRI.
TELECONNECTION PERSISTENCE...THE GENERAL PATTERN OF NORTHWEST FLOW
ALOFT WITH RE-ENFORCING DUMPS OF CANADIAN HIGHS DOWN THE UPPER
MIDWEST AND WESTERN GRT LKS OVER THE WEEKEND AND INTO MID NEXT
WEEK. SOME CHANCE OF A NORTHWEST FLOW PRECIS EVENT IN ONE OF THESE
TRANSITIONS...WITH ONE WINDOW OF OPPORTUNITY LOOKING LIKE SUNDAY
NIGHT INTO MONDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 105 PM CDT WED AUG 7 2013
MAINLY VFR CONDS THROUGH THURSDAY MORNING. HOWEVER MVFR BR 10-15Z/08
AT KBRL. NORTHWEST TO NORTH WINDS AROUND 10 KNOTS THIS AFTERNOON
WITH WINDS BECOMING NORTHEAST TO EAST AT LESS THAN 10 KNOTS
TONIGHT INTO THURSDAY.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...HAASE
SHORT TERM...12
LONG TERM...12
AVIATION...HAASE
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1021 AM CDT WED AUG 7 2013
.UPDATE...
ISSUED AT 1020 AM CDT WED AUG 7 2013
A FEW THUNDERSTORMS HAVE DEVELOPED ALONG THE COLD FRONT FROM JUST
NORTHWEST OF MACOMB TO NEAR KEWANEE AND WERE MOVING EAST/NORTHEAST.
SOME OF THE STORMS WILL PRODUCE BRIEF HEAVY RAINFALL. THE FRONT
WILL CONTINUE TO SAG TO THE SOUTHEAST OF THE CWA BY NOON OR 1 PM.
THE HRRR MESO MODEL INDICATES THE FRONT BECOMING MORE ACTIVE BY
EARLY THIS AFTERNOON BUT BY THEN THE FRONT SHOULD BE SOUTHEAST OF
THE DVN CWA.
OTHERWISE...BEHIND THE FRONT WINDS WILL TURN NORTHWEST TO NORTH
WITH GRADUALLY LOWERING DEW POINTS. CANADIAN HIGH WILL BUILD INTO
THE REGION TONIGHT AND THURSDAY WITH MUCH MORE COMFORTABLE TEMPERATURES
AND HUMIDITY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 322 AM CDT WED AUG 7 2013
WESTERN GRT LKS FRONTAL SYSTEM TO CONTINUE TO SWEEP THROUGH THE
AREA THIS MORNING AND WILL WALK OUT ANY LINGERING CONVECTION/STORM
CLUSTERS THROUGH 14Z TO 16Z...MAY DECAY BEFORE THEN LIKE LATEST
HIRES MODEL RUNS SUGGEST. DESPITE FROPA...SOME LAG IN LLVL COOLER
AIR ADVECTION AND EXPECT TEMPS TO WARM INTO THE LOW TO MID 80S
IN THE SOUTHEASTERN HALF OF THE DVN CWA...UPPER 70S IN THE
NORTHWESTERN FCST AREA. THESE TEMPS BANKING ON CONVECTIVE DEBRIS
ERODING DIURNALLY. A BOUT OF PASSING SFC RIDGING WILL MAKE FOR A
MAINLY CLEAR SKY AND COOLER TEMPS TONIGHT WITH SOME 50S OCCURRING
NORTH OF I80. VALLEY FOG POSSIBLE.
.LONG TERM...(THURSDAY THROUGH NEXT TUESDAY)
ISSUED AT 322 AM CDT WED AUG 7 2013
GENERALLY BELOW NORMAL TEMP REGIME CONTINUES. MAIN STORY AT THE
END OF THE WEEK WILL BE ACTIVE GRT BSN AND SOUTHERN STREAM FLOWS
LOADED WITH MONSOONAL MOISTURE AND IF SOME OF IT CAN MAKE IT THIS
FAR NORTH. LATEST MODEL TRENDS CONTINUE TO SHOW SOME PHASING
POTENTIAL WITH NORTHERN PLAINS/UPPER MIDWEST TROFFINESS WHICH
WOULD INDUCE SOME LLVL CYCLOGENESIS ACRS THE SOUTHERN PLAINS OVER
TO THE MID MS RVR VALLEY. TIMING OF THIS PROCESS AND HOW FAR NORTH
IT CAN MAKE IT STILL UNCERTAIN WITH MODEL VARIABILITY...BUT SIGNALS
ARE THERE THAT AT LEAST THE SOUTHERN THIRD TO HALF OF THE CWA MAY
GET IN ON SOME OVERRUNNING PRECIP/SOME POTENTIALLY DECENT SOAKING RAINS/
AT WEEKS END. THE 00Z GFS AND UKMET TARGET LATE THU NIGHT INTO
FRIDAY...WHILE THE 00Z ECMWF IS POINTING AT FRI NIGHT AND NOT AS
FAR NORTH AS THE PREVIOUS MENTIONED MODELS WITH IT/S PRECIP SWATH.
MAY TREND TOWARD THE UKMET AND GFS WITH POPS INCREASING IN THE
SOUTH THU NIGHT INTO FRI FOR NOW. BUST POTENTIAL FOR ADVERTISED
TEMPS TO BE TOO WARM IN THE SOUTH HALF IF THIS MATERIALIZES
BECAUSE OF PRECIP AND CLOUD COVER ESPECIALLY ON FRI.
TELECONNECTION PERSISTENCE...THE GENERAL PATTERN OF NORTHWEST FLOW
ALOFT WITH RE-ENFORCING DUMPS OF CANADIAN HIGHS DOWN THE UPPER
MIDWEST AND WESTERN GRT LKS OVER THE WEEKEND AND INTO MID NEXT
WEEK. SOME CHANCE OF A NORTHWEST FLOW PRECIS EVENT IN ONE OF THESE
TRANSITIONS...WITH ONE WINDOW OF OPPORTUNITY LOOKING LIKE SUNDAY
NIGHT INTO MONDAY.
&&
.AVIATION...(FOR THE 12Z TADS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 637 AM CDT WED AUG 7 2013
A COLD FRONT WILL MOVE THROUGH THE AREA BY EARLY THIS AFTERNOON.
GROUND FOG AND PATCHY STRATUS WITH BASES BELOW 1FT OCCURRING IN
THE WARM MOIST AIR AHEAD OF THE FRONT SHOULD LIFT OR DISSIPATE WITH
HEATING EARLY THIS MORNING. THE PREFRONTAL AIRMASS SHOULD
DESTABILIZE ENOUGH BY LATE MORNING TO ALLOW A FEW THUNDERSTORMS TO
DEVELOP ALONG THE FRONT. THESE STORMS COULD IMPACT KBRL LATE THIS
MORNING OR EARLY THIS AFTERNOON. THERE SHOULD BE ENOUGH RESIDUAL
MOISTURE BEHIND THE FRONT FOR SOME SCATTERED CU DEVELOPMENT THIS
AFTERNOON. FORECAST MODELS WERE SUGGESTING THE POTENTIAL FOR SOME
STRATUS MOVING OFF LAKE MICHIGAN LATE TONIGHT AND REACHING THE
MISSISSIPPI RIVER BY THURSDAY MORNING. IF THIS OCCURS THEN KMLI
AND KDBQ COULD SEE SOME LOW CIGS BY 12Z THURSDAY.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...HAASE
SHORT TERM...12
LONG TERM...12
AVIATION...DLF
AREA FORECAST DISCUSSION
NWS GOODLAND KS
226 PM MDT WED AUG 7 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 221 PM MDT WED AUG 7 2013
LATEST WV IMAGERY AND RAP H5 ANALYSIS INDICATES ZONAL FLOW STILL IN
PLACE ACROSS THE CONUS WITH STRONG CLOSED LOW OVER CENTRAL CANADA.
AN EMBEDDED H5/H7 LOW IN IN PLACE UPSTREAM OF THE CWA OVER THE FOUR
CORNER REGION.
LARGE SCALE FORCING AND MID LEVEL MOISTURE CONTINUE TO ADVECT INTO
THE CWA FROM THE SOUTHWEST AHEAD OF THE FOUR CORNERS TROUGH. RAP
ANALYSIS STILL SHOWS 500-1500 J/KG OF MUCAPE IN PLACE...SO
THUNDERSTORMS ARE CERTAINLY POSSIBLE. AT THIS POINT OVERALL THREAT
FOR SEVERE THUNDERSTORMS SEEMS LOW. MODELS CONTINUE TO PAIN BULLS EYE
OF 0.50+ QPF...FAVORING SOUTHERN LOCATIONS. AT THE SAME
TIME...NAM/SREF HAVE TRENDED FURTHER NORTH WHICH DOES SEEM TO HAVE
SUPPORT LOOKING AT LATEST RADAR TRENDS. I ADJUSTED POPS ACCORDINGLY.
RAP INDICATES PWATS IN EXCESS OF 1.3"...AND WHILE LOWER THAN THE LAST
FEW DAYS IS STILL CLIMATOLOGICALLY HIGH. BASED ON RADAR/SATELLITE
TRENDS...AND THE NATURE OF THIS PATTERN...I AM CURRENTLY EXPECTING
SEVERAL PERIODS OF SHOWERS/THUNDERSTORMS ROTATING ACROSS OUR CWA
THROUGH TONIGHT...BEFORE THE MAIN TROUGH MOVES ACROSS THE REGION. AS
THIS OCCURS WE MIGHT SEE OUR BEST CHANCE FOR HEAVY PRECIP ACROSS
MOST OF THE CWA. THERE IS STILL SOME INDICATION THIS COULD OCCUR
LATER IN THE DAY THURSDAY...HOWEVER CONSENSUS SUPPORTS A MORNING
TROUGH PASSAGE AND DECREASING CHANCES THROUGH MIDDAY THURSDAY.
REGARDING WATCH...CONSIDERING THE LIKELIHOOD THAT PRECIPITATION WILL
REMAIN LIGHT TO MODERATE ACROSS MOST OF THE AREA WITH HIGHEST
TOTALS SPREAD OUT OVER 6-12HR PERIOD...I AM STARTING TO QUESTION
THE POTENTIAL FOR FLASH FLOODING. LATEST 6HR FLASH FLOOD GUIDANCE IS
GENERALLY IN THE 2-3 INCH RANGE OVER THE WATCH AREA AND UNLESS WE CAN
GET A STRONG THUNDERSTORM EMBEDDED WITHIN THE LARGER AREA OF
LIGHT-MODERATE RAIN IM NOT SURE WE WILL SEE THESE RATES. WE MAY BE
ABLE TO CANCEL THE WATCH LATER THIS EVENING...BUT I WOULD RATHER
WAIT AND SEE HOW CONVECTION EVOLVES.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 221 PM MDT WED AUG 7 2013
THURSDAY EVENING THE UPPER LEVEL SHORT WAVE TROUGH WILL MOVE EAST OF
THE AREA. WITH THE NOSE OF THE LOW LEVEL JET OVER THE EASTERN PART
OF THE AREA AS WELL...AND A WEAK RIGHT ENTRANCE REGION OF THE 300MB
JET OVER THE AREA...THERE MAY BE SOME LINGERING PRECIP. ACTIVITY
AHEAD OF THE EXITING TROUGH. MEANWHILE BEHIND THE TROUGH DRIER AIR
WILL BE MOVING IN WHICH WILL CAUSE PRECIP. CHANCES TO DECLINE FROM
WEST TO EAST. HOWEVER WITH COOLER AIR MOVING IN THERE WILL BE SOME
INSTABILITY LINGERING BEHIND THE TROUGH. WITH SOME MUCH SMALLER
UPPER LEVEL DISTURBANCES MOVING THROUGH BEHIND THE MAIN
FEATURE...ISOLATED STORMS CANNOT BE RULED OUT DURING THE EVENING AND
INTO THE OVERNIGHT HOURS.
FRIDAY ANOTHER UPPER LEVEL SHORT WAVE TROUGH WILL DEVELOP OVER FAR
EASTERN COLORADO IN THE LATE AFTERNOON. AT THE SURFACE A TROUGH
WILL BE OVER THE WESTERN BORDER OF THE TRI-STATE AREA BENEATH THE
SHORT WAVE. WITH SURFACE CONVERGENCE AND UPPER LEVEL
LIFT...ANTICIPATE SOME STORMS DEVELOPING ALONG THE SURFACE TROUGH
DURING THE MID AFTERNOON INTO THE EARLY EVENING. MEAN STORM
MOTIONS WILL BE VERY SLOW...WITH MOTIONS TURNING FROM THE WEST TO
THE NORTH. THESE MOTIONS WILL KEEP THE STORMS CONFINED TO THE
SURFACE TROUGH. BY THE LATE EVENING ANY STORMS THAT DEVELOPED WILL
DISSIPATE AS THE ENVIRONMENT STABILIZES. THE MAIN THREAT WITH ANY
STORMS THAT DEVELOP WILL BE HEAVY RAINFALL.
SATURDAY THROUGH WEDNESDAY THE UPPER LEVEL RIDGE OVER THE SOUTHWEST
CONUS WILL SLOWLY BUILD NORTHWARD...WITH THE TRI-STATE AREA
REMAINING UNDER THE PERIPHERY OF THE RIDGE. AS A RESULT MULTIPLE
UPPER LEVEL SHORT WAVE TROUGHS WILL MOVE OVER THE AREA THROUGH THE
PERIOD. THE STRONGER TROUGHS WILL MOVE OVER THE AREA AFTER THE
WEEKEND. MEANWHILE A FRONT WILL WAFFLE BACK AND FORTH OVER THE
AREA DURING THIS PERIOD WHICH WILL CAUSE TEMPERATURES TO VARY
SOMEWHAT. AT THIS TIME RANGE DIFFICULT TO KNOW WHERE THE FRONT WILL
BE SO WILL KEEP THE CONSENSUS TEMP. FORECAST OF NEAR NORMAL.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1145 AM MDT WED AUG 7 2013
VFR CONDITIONS SHOULD PREVAIL AT BOTH TERMINALS THROUGH THE VALID
TAF PERIOD. MVFR/IFR CONDITIONS CANT BE RULED OUT IF A STRONGER
THUNDERSTORM WERE TO OCCUR...HOWEVER CONFIDENCE IS TOO LOW TO ADD
MENTION AT THIS TIME. SHOWERS/THUNDERSTORMS ARE EXPECTED TO SPREAD
EAST THROUGH THE AFTERNOON WITH BEST CHANCES AT BOTH TERMINALS
THROUGH THIS EVENING...THOUGH THIS ACTIVITY COULD POSSIBLY LINGER
ALL NIGHT. ADDITIONAL SHOWERS/THUNDERSTORMS MAY DEVELOP THURSDAY
MORNING...I WAS NOT CONFIDENT ENOUGH TO PREVAIL THE CONDITIONS THU
MORNING AT EITHER TERMINAL. INSTEAD I INCLUDED VCSH THROUGH THE
REMAINING TAF PERIOD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...FLASH FLOOD WATCH THROUGH THURSDAY MORNING FOR KSZ027>029-041-
042.
CO...FLASH FLOOD WATCH THROUGH THURSDAY MORNING FOR COZ092.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...JTL
AVIATION...DR
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
111 PM CDT Wed Aug 7 2013
...UPDATED FOR THE AVIATION DISCUSSION...
.SYNOPSIS...
ISSUED AT 1229 AM CDT WED AUG 7 2013
At 00z Wednesday a +100kt 250mb jet extended from South Dakota
into the western great lakes. The right entrance region was
located near central Nebraska/northern Kansas. At the 500mb level
an upper level trough was located over eastern Montana and an
upper level ridge axis was located across the pacific northwest.
Further south over the southern plains an upper high was located
near the gulf coast of Texas and an upper level low/trough moved
northward out of Mexico into eastern Arizona. Convection that
developed across southwest Kansas near the Colorado border around
00z Wednesday was currently moving east/southeast across south
central Kansas at 05z. These storms appeared to located where the
better 850mb moisture, frontogenesis, and warm air advection were
occurring earlier this evening. Further north another area of
convection had developed during the evening hours from northeast
Colorado into western Nebraska. This a located near a surface
trough of low pressure and where better moist upslope flow was
present along with better mid level lapse rates. RAP also hinted
at a subtle upper level wave was located in this area at 00z.
&&
.SHORT TERM...(Today and tonight)
ISSUED AT 251 AM CDT WED AUG 7 2013
The NAM, RAP, GFS were all in decent agreement this morning with
moving an upper level trough across northern Kansas early this
morning. Based on the 06z location of this upper wave it appears
that an area of convection had developed ahead of this system
based on the composite radar loop. Given this and the timing of
the upper level trough will raise precipitation chances in the
north to at least high chance for early this morning. Further
south the chances for convection early will be less but still
given weak lift forecast across southwest Kansas will keep some
small pops going early today.
Convection should briefly taper off as the upper level trough
passes east of the area, however by the early afternoon the
chances for convection will begin to improve, especially across
far western and southwest Kansas where moist upslope flow is
expected and better afternoon instability and 0-6km shear is
forecast to be located. Convection will then increase in areal
coverage as it spreads east across the remainder of western Kansas
late today and overnight as the Arizona upper low/trough moves
east across New Mexico. Heavy rainfall will still be an issue
later today and overnight given the precipitable water content on
the Dodge City soundings at 1.42 inches at 00z Wednesday. Also
strong damaging winds and large hail will be possible from some
these storms late today and early tonight. The flood watch
currently in the effect still looks on track given several
opportunities of heavy precipitation later today through Thursday.
.LONG TERM...(Thursday through Tuesday)
ISSUED AT 315 AM CDT WED AUG 7 2013
A cool and wet period is forecast for the area with much above
average forecaster certainty for significant measurable rainfall
through Thursday. The synoptic set up includes an already very moist
atmosphere across the central high plains, characterized by dew
points in the 60s and 70s. Additionally, and upper high center
over the Southern Plains and Gulf region helping transport
additional pacific moisture poleward. The kinematic fields will
include the slow development of a Central Rockies through which
will place Western Kansas under a favorable positive vorticity and
warm advection region for maximum lift potential Thursday.
Additionally, a surface/850 mb frontal zone will air in low level
frontogenesis adding to the QG component. These elements have
given enough confidence to raise precipitation chances into the
categorical range during the day 2 period. The slow nature of this
existing wave will create a fluid forecast situation . The jet
streak will still leave a broad right rear quadrant entrance
region into Friday, and thunderstorm cannot be ruled out through
this period as well, although the trend would be downward. During
this period it is likely that a widespread one to two inches of
rain will fall over the entire southwest and central Kansas
region. Areas of higher rainfall perhaps in excess of 5 inches are
possible based on model run totals, but with relatively low
forecaster confidence with respect to coverage.
From Friday and onward increased ridging along the High Plains
region will create a warming trend with opportunities for severe
weather producing MCS events into early next week.
&&
.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
ISSUED AT 105 PM CDT WED AUG 7 2013
MVFR Cigs have moved into the kddc area, and will likely spread
west and north as the afternoon and evening progress. Scattered
thunderstorms are also expected to develop, but will only be
carried in the Tafs as vcsh until after 01z. Then a tempo group
for 2sm +tsra will cover the period from 01z to 05z. Cigs from
01-05Z should remain in the Mvfr ovc040 range.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 66 72 65 78 / 90 80 60 30
GCK 65 71 65 77 / 90 80 60 30
EHA 65 73 62 80 / 70 80 50 30
LBL 67 75 64 80 / 80 80 50 30
HYS 65 76 65 76 / 90 80 70 40
P28 69 78 66 81 / 70 80 50 30
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
FLOOD WATCH through Thursday afternoon FOR KSZ045-046-064>066-
079-081.
&&
$$
SYNOPSIS...BURGERT
SHORT TERM...BURGERT
LONG TERM...RUSSELL
AVIATION...BURKE
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
739 AM CDT Wed Aug 7 2013
...UPDATED FOR AVIATION...
.SYNOPSIS...
ISSUED AT 1229 AM CDT WED AUG 7 2013
At 00z Wednesday a +100kt 250mb jet extended from South Dakota
into the western great lakes. The right entrance region was
located near central Nebraska/northern Kansas. At the 500mb level
an upper level trough was located over eastern Montana and an
upper level ridge axis was located across the pacific northwest.
Further south over the southern plains an upper high was located
near the gulf coast of Texas and an upper level low/trough moved
northward out of Mexico into eastern Arizona. Convection that
developed across southwest Kansas near the Colorado border around
00z Wednesday was currently moving east/southeast across south
central Kansas at 05z. These storms appeared to located where the
better 850mb moisture, frontogenesis, and warm air advection were
occurring earlier this evening. Further north another area of
convection had developed during the evening hours from northeast
Colorado into western Nebraska. This a located near a surface
trough of low pressure and where better moist upslope flow was
present along with better mid level lapse rates. RAP also hinted
at a subtle upper level wave was located in this area at 00z.
&&
.SHORT TERM...(Today and tonight)
ISSUED AT 251 AM CDT WED AUG 7 2013
The NAM, RAP, GFS were all in decent agreement this morning with
moving an upper level trough across northern Kansas early this
morning. Based on the 06z location of this upper wave it appears
that an area of convection had developed ahead of this system
based on the composite radar loop. Given this and the timing of
the upper level trough will raise precipitation chances in the
north to at least high chance for early this morning. Further
south the chances for convection early will be less but still
given weak lift forecast across southwest Kansas will keep some
small pops going early today.
Convection should briefly taper off as the upper level trough
passes east of the area, however by the early afternoon the
chances for convection will begin to improve, especially across
far western and southwest Kansas where moist upslope flow is
expected and better afternoon instability and 0-6km shear is
forecast to be located. Convection will then increase in areal
coverage as it spreads east across the remainder of western Kansas
late today and overnight as the Arizona upper low/trough moves
east across New Mexico. Heavy rainfall will still be an issue
later today and overnight given the precipitable water content on
the Dodge City soundings at 1.42 inches at 00z Wednesday. Also
strong damaging winds and large hail will be possible from some
these storms late today and early tonight. The flood watch
currently in the effect still looks on track given several
opportunities of heavy precipitation later today through Thursday.
.LONG TERM...(Thursday through Tuesday)
ISSUED AT 315 AM CDT WED AUG 7 2013
A cool and wet period is forecast for the area with much above
average forecaster certainty for significant measurable rainfall
through Thursday. The synoptic set up includes an already very moist
atmosphere across the central high plains, characterized by dew
points in the 60s and 70s. Additionally, and upper high center
over the Southern Plains and Gulf region helping transport
additional pacific moisture poleward. The kinematic fields will
include the slow development of a Central Rockies through which
will place Western Kansas under a favorable positive vorticity and
warm advection region for maximum lift potential Thursday.
Additionally, a surface/850 mb frontal zone will air in low level
frontogenesis adding to the QG component. These elements have
given enough confidence to raise precipitation chances into the
categorical range during the day 2 period. The slow nature of this
existing wave will create a fluid forecast situation . The jet
streak will still leave a broad right rear quadrant entrance
region into Friday, and thunderstorm cannot be ruled out through
this period as well, although the trend would be downward. During
this period it is likely that a widespread one to two inches of
rain will fall over the entire southwest and central Kansas
region. Areas of higher rainfall perhaps in excess of 5 inches are
possible based on model run totals, but with relatively low
forecaster confidence with respect to coverage.
From Friday and onward increased ridging along the High Plains
region will create a warming trend with opportunities for severe
weather producing MCS events into early next week.
&&
.AVIATION...(For the 12Z TAFS through 12Z Thursday morning)
ISSUED AT 729 AM CDT WED AUG 7 2013
Overcast stratus will remain in the vfr category across the area
with scattered lower stratus in some areas. Thunderstorms now
exiting the region have promoted gusty nortwest winds around 20
knots thios morning. Deep moist convection will redevelop by
afternoon and become more numerous in the evening.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 82 66 72 65 / 40 90 80 60
GCK 80 65 71 65 / 40 90 80 60
EHA 83 65 73 62 / 70 70 80 50
LBL 83 67 75 64 / 40 80 80 50
HYS 79 65 76 65 / 50 90 80 70
P28 85 69 78 66 / 30 70 80 50
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
FLOOD WATCH through Thursday afternoon FOR KSZ045-046-064>066-
079-081.
&&
$$
SYNOPSIS...BURGERT
SHORT TERM...BURGERT
LONG TERM...RUSSELL
AVIATION...RUSSELL
AREA FORECAST DISCUSSION
NWS GOODLAND KS
539 AM MDT WED AUG 7 2013
.UPDATE...
ISSUED AT 745 PM MDT TUE AUG 6 2013
UPDATED TO REMOVE THE CONVECTIVE WATCH AND ACCOUNT FOR DECREASING
THUNDERSTORM COVERAGE ACROSS THE SOUTH AND ADDITIONAL
THUNDERSTORMS MOVING ACROSS NORTHEAST COLORADO INTO FAR SOUTHWEST
NEBRASKA AND FAR NORTHWEST KANSAS.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 222 PM MDT TUE AUG 6 2013
LATEST WV IMAGERY AND RAP ANALYSIS SHOWS NW FLOW STILL IN PLACE
ACROSS THE NORTHERN AND CENTRAL CONUS...WITH A RIDGE CENTERED OVER
TEXAS AND A WEAKENED CLOSED LOW OVER SOUTHERN ARIZONA. A VERY
MOIST/UNSTABLE AIRMASS REMAINS IN PLACE OVER OUR CWA WITH TD VALUES
ACROSS NW KANSAS IN THE MID 60S TO LOW 70S...AND SB CAPE VALUES IN
THE 2000-4000 J/KG RANGE FROM THE WEST TO THE EAST. A SURFACE
TROUGH IS CURRENTLY CENTERED ALONG THE KS/CO BORDER...WITH LOWER
TD VALUES AND MUCH MORE STABLE AIRMASS TO THE WEST OF THIS
FEATURE.
THUNDERSTORMS HAVE ALREADY DEVELOPED ALONG THIS TROUGH AXIS
IN OUR FAR SW CWA. I WOULD EXPECT ADDITIONAL THUNDERSTORM
ACTIVITY TO INITIATE ALONG AND EAST OF THIS FEATURE THROUGH THIS
AFTERNOON AND EVENING. LATEST HRRR INDICATED ACTIVITY FORMING AHEAD OF
THIS AXIS AND FORMING INTO A CLUSTER/LINE AND SHIFTING TO THE
SOUTH AND EAST. BASED ON NAM/GFS SUPPORTING BETTER COVERAGE IN THE
SOUTH...WHICH IS IN LINE WITH SHORT RANGE GUIDANCE I KEPT THIS
TREND. A COLD FRONT WILL APPROACH THE CWA TONIGHT...WITH ELEVATED
INSTABILITY/GOOD MOISTURE LINGERING I DECIDED TO KEEP THUNDERSTORM
MENTION THROUGH THE NIGHT. CONSIDERING STORM MOTION WITH
INDIVIDUAL CELLS AND MOISTURE AVAILABILITY I AM CONCERNED WE COULD
SEE LOCALIZED FLASH FLOODING THIS AFTERNOON/EVENING IN ADDITION TO
SEVERE HAIL/WIND THREAT. COVERAGE IS A QUESTION THOUGH...WITH ANY
CLUSTER/LINE LIKELY BEGINNING TO PROPAGATE QUICKER AS IT FORMS A
COLD POOL IN OUR SOUTH. AS A RESULT WE MAY NOT ACTUALLY SEE AS
WIDESPREAD OF A THREAT OF FLASH FLOODING TODAY/TONIGHT.
WEDNESDAY...COLD FRONT WILL DROP SOUTH OF OUR CWA AND BE NEAR THE
KS/OK BORDER BY LATE WED AFTERNOON. DEEP MOIST EASTERLY FLOW
ALONG/NORTH OF THIS FEATURE COMBINED WITH INCREASING LARGE SCALE
ASCENT WILL SUPPORT NUMEROUS TO WIDESPREAD SHOWERS/THUNDERSTORMS
ACROSS OUR SOUTHERN CWA. I AM CONCERNED THAT THE BEST COVERAGE MAY
BE TIED TO THE FRONT...WHICH WOULD PUT BETTER COVERAGE SOUTH OF OUR
CWA. HOWEVER THERE IS ENOUGH MOISTURE/FORCING ALOFT TO SUPPORT
HIGHER POPS ACROSS OUR SOUTHERN CWA IN THE AFTERNOON. A RESULT OF
THICK CLOUD COVER AND CAA THROUGH THE DAY WILL BE HIGH TEMPERATURES
WELL BELOW NORMAL (UPPER 60S TO MID 70S). PREVIOUS FORECAST HAD THIS
COOLER TREND...SO ONLY MINOR ADJUSTMENTS MADE. WHILE WE MAY NEED A
FLASH FLOOD WATCH FOR WED AFTERNOON DUE TO POSSIBLE TRAINING AND
WIDESPREAD HEAVY RAIN COVERAGE IN THE SOUTH...I FELT IT WAS BEST TO
CONCENTRATE PUBLIC ATTENTION ON ONGOING THUNDERSTORMS THIS
AFTERNOON/EVENING TO AVOID CONFUSION. WE MAY NEED TO ISSUE A WATCH
ON OVERNIGHT SHIFTS IF IT LOOKS LIKE OUR SOUTHERN CWA WILL REMAIN
FAVORABLE FOR A LARGE SCALE FLASH FLOOD THREAT.
.LONG TERM...(SATURDAY THROUGH TUESDAY)
ISSUED AT 308 AM MDT WED AUG 7 2013
DIFFERENCES EXIST IN THE TIMING AND CHARACTER OF SHORTWAVE THAT
MOVES ACROSS THE AREA EARLY IN THE EXTENDED PERIOD. AT THE START OF
THE EXTENDED...RELATIVELY COOL/DRY NORTHEASTERLY POST FRONTAL
SURFACE FLOW WILL BE IN PLACE ACROSS THE AREA EARLY SATURDAY. THIS
WILL TRANSITION INTO SOUTHEASTERLY SURFACE FLOW LATER IN THE DAY
ON SATURDAY. ADEQUATE MOISTURE AND LOW LEVEL CONVERGENCE MAY RESULT IN
SHOWERS AND THUNDERSTORMS DEVELOPING SATURDAY
AFTERNOON...ESPECIALLY ACROSS THE WESTERN PORTION OF THE AREA.
ADDITIONALLY...CONVECTION THAT DEVELOPS FROM ELEVATED HEATING IN
THE COLORADO MAY MOVE EASTWARD REACHING WESTERN PORTIONS OF THE
AREA DURING THE EVENING. THE PATTERN CHANGES LITTLE THROUGH THE
WEEKEND AND INTO THE BEGINNING OF NEXT WEEK. WESTERLIES ALOFT WILL
CONTINUE WITH EMBEDDED MINOR DIFFICULT TO TIME SHORTWAVE TROUGHS
NECESSITATING SLIGHT TO LOW CHANCE POPS EACH DAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 538 AM MDT WED AUG 7 2013
VFR CONDITIONS ARE EXPECTED OVER THE NEXT 24 HOURS. PRECIPITATION
COULD BECOME RELATIVELY WIDESPREAD TODAY BUT THERE ARE SOME TIMING
UNCERTAINTIES ON WHEN SHRA OR TSRA MIGHT IMPACT EITHER SITE.
PRECIPITATION COULD CONTINUE OVERNIGHT TOO...BUT THE CURRENT TAF
DOES NOT REFLECT THIS SINCE UNCERTAINTY EXISTS IN TIMING AND
PLACEMENT. THE MOST LIKELY SITE TO BE IMPACTED BY SHOWERS OR
THUNDERSTORMS TODAY THROUGH THE EVENING WILL BE GLD. SOME STRATUS
MAY OCCUR IN THE MVFR CATEGORY OVERNIGHT AS WELL. SIGNIFICANT
VISIBILITY RESTRICTIONS ARE UNLIKELY THROUGH THE NEXT 24 HOURS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR KSZ027>029-041-042.
CO...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR COZ092.
NE...NONE.
&&
$$
UPDATE...LOCKHART
SHORT TERM...DR
LONG TERM...BRB
AVIATION...BRB
AREA FORECAST DISCUSSION
NWS GOODLAND KS
308 AM MDT WED AUG 7 2013
.UPDATE...
ISSUED AT 745 PM MDT TUE AUG 6 2013
UPDATED TO REMOVE THE CONVECTIVE WATCH AND ACCOUNT FOR DECREASING
THUNDERSTORM COVERAGE ACROSS THE SOUTH AND ADDITIONAL
THUNDERSTORMS MOVING ACROSS NORTHEAST COLORADO INTO FAR SOUTHWEST
NEBRASKA AND FAR NORTHWEST KANSAS.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 222 PM MDT TUE AUG 6 2013
LATEST WV IMAGERY AND RAP ANALYSIS SHOWS NW FLOW STILL IN PLACE
ACROSS THE NORTHERN AND CENTRAL CONUS...WITH A RIDGE CENTERED OVER
TEXAS AND A WEAKENED CLOSED LOW OVER SOUTHERN ARIZONA. A VERY
MOIST/UNSTABLE AIRMASS REMAINS IN PLACE OVER OUR CWA WITH TD VALUES
ACROSS NW KANSAS IN THE MID 60S TO LOW 70S...AND SB CAPE VALUES IN
THE 2000-4000 J/KG RANGE FROM THE WEST TO THE EAST. A SURFACE
TROUGH IS CURRENTLY CENTERED ALONG THE KS/CO BORDER...WITH LOWER
TD VALUES AND MUCH MORE STABLE AIRMASS TO THE WEST OF THIS
FEATURE.
THUNDERSTORMS HAVE ALREADY DEVELOPED ALONG THIS TROUGH AXIS
IN OUR FAR SW CWA. I WOULD EXPECT ADDITIONAL THUNDERSTORM
ACTIVITY TO INITIATE ALONG AND EAST OF THIS FEATURE THROUGH THIS
AFTERNOON AND EVENING. LATEST HRRR INDICATED ACTIVITY FORMING AHEAD OF
THIS AXIS AND FORMING INTO A CLUSTER/LINE AND SHIFTING TO THE
SOUTH AND EAST. BASED ON NAM/GFS SUPPORTING BETTER COVERAGE IN THE
SOUTH...WHICH IS IN LINE WITH SHORT RANGE GUIDANCE I KEPT THIS
TREND. A COLD FRONT WILL APPROACH THE CWA TONIGHT...WITH ELEVATED
INSTABILITY/GOOD MOISTURE LINGERING I DECIDED TO KEEP THUNDERSTORM
MENTION THROUGH THE NIGHT. CONSIDERING STORM MOTION WITH
INDIVIDUAL CELLS AND MOISTURE AVAILABILITY I AM CONCERNED WE COULD
SEE LOCALIZED FLASH FLOODING THIS AFTERNOON/EVENING IN ADDITION TO
SEVERE HAIL/WIND THREAT. COVERAGE IS A QUESTION THOUGH...WITH ANY
CLUSTER/LINE LIKELY BEGINNING TO PROPAGATE QUICKER AS IT FORMS A
COLD POOL IN OUR SOUTH. AS A RESULT WE MAY NOT ACTUALLY SEE AS
WIDESPREAD OF A THREAT OF FLASH FLOODING TODAY/TONIGHT.
WEDNESDAY...COLD FRONT WILL DROP SOUTH OF OUR CWA AND BE NEAR THE
KS/OK BORDER BY LATE WED AFTERNOON. DEEP MOIST EASTERLY FLOW
ALONG/NORTH OF THIS FEATURE COMBINED WITH INCREASING LARGE SCALE
ASCENT WILL SUPPORT NUMEROUS TO WIDESPREAD SHOWERS/THUNDERSTORMS
ACROSS OUR SOUTHERN CWA. I AM CONCERNED THAT THE BEST COVERAGE MAY
BE TIED TO THE FRONT...WHICH WOULD PUT BETTER COVERAGE SOUTH OF OUR
CWA. HOWEVER THERE IS ENOUGH MOISTURE/FORCING ALOFT TO SUPPORT
HIGHER POPS ACROSS OUR SOUTHERN CWA IN THE AFTERNOON. A RESULT OF
THICK CLOUD COVER AND CAA THROUGH THE DAY WILL BE HIGH TEMPERATURES
WELL BELOW NORMAL (UPPER 60S TO MID 70S). PREVIOUS FORECAST HAD THIS
COOLER TREND...SO ONLY MINOR ADJUSTMENTS MADE. WHILE WE MAY NEED A
FLASH FLOOD WATCH FOR WED AFTERNOON DUE TO POSSIBLE TRAINING AND
WIDESPREAD HEAVY RAIN COVERAGE IN THE SOUTH...I FELT IT WAS BEST TO
CONCENTRATE PUBLIC ATTENTION ON ONGOING THUNDERSTORMS THIS
AFTERNOON/EVENING TO AVOID CONFUSION. WE MAY NEED TO ISSUE A WATCH
ON OVERNIGHT SHIFTS IF IT LOOKS LIKE OUR SOUTHERN CWA WILL REMAIN
FAVORABLE FOR A LARGE SCALE FLASH FLOOD THREAT.
.LONG TERM...(SATURDAY THROUGH TUESDAY)
ISSUED AT 308 AM MDT WED AUG 7 2013
DIFFERENCES EXIST IN THE TIMING AND CHARACTER OF SHORTWAVE THAT
MOVES ACROSS THE AREA EARLY IN THE EXTENDED PERIOD. AT THE START OF
THE EXTENDED...RELATIVELY COOL/DRY NORTHEASTERLY POST FRONTAL
SURFACE FLOW WILL BE IN PLACE ACROSS THE AREA EARLY SATURDAY. THIS
WILL TRANSITION INTO SOUTHEASTERLY SURFACE FLOW LATER IN THE DAY
ON SATURDAY. ADEQUATE MOISTURE AND LOW LEVEL CONVERGENCE MAY RESULT IN
SHOWERS AND THUNDERSTORMS DEVELOPING SATURDAY
AFTERNOON...ESPECIALLY ACROSS THE WESTERN PORTION OF THE AREA.
ADDITIONALLY...CONVECTION THAT DEVELOPS FROM ELEVATED HEATING IN
THE COLORADO MAY MOVE EASTWARD REACHING WESTERN PORTIONS OF THE
AREA DURING THE EVENING. THE PATTERN CHANGES LITTLE THROUGH THE
WEEKEND AND INTO THE BEGINNING OF NEXT WEEK. WESTERLIES ALOFT WILL
CONTINUE WITH EMBEDDED MINOR DIFFICULT TO TIME SHORTWAVE TROUGHS
NECESSITATING SLIGHT TO LOW CHANCE POPS EACH DAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1148 PM MDT TUE AUG 6 2013
INITIAL CONCERNS ARE ONGOING CONVECTION TO THE WEST OF BOTH TAF
SITES. GLD WILL EXPERIENCE A SHIFT IN WIND DIRECTION AND INCREASE
IN SPEEDS AS A RESULT OF AN OUTFLOW BOUNDARY SHORTLY AFTER 06Z.
THUNDERSTORMS SHOULD DECREASE OVER THE NEXT FEW HOURS. OTHER
CONCERNS FOR GLD WAS A BRIEF REDUCTION OF VISIBILITY LAST HOUR.
THIS APPEARS TO BE TEMPORARY. FURTHER REDUCTIONS ARE UNLIKELY
ESPECIALLY AFTER THUNDERSTORM OUTFLOW BOUNDARY PASSES THROUGH. FOR
MCCOOK...THUNDERSTORMS MAY BE IN THE VICINITY BY AROUND 08Z. SOME
FOG COULD FORM AT MCK BUT NEARBY THUNDERSTORMS AND RESULTANT
OUTFLOW MAY KEEP WINDS UP ENOUGH TO PREVENT THIS. TRENDS WILL BE
MONITORED AND AMENDMENTS MAY BE NEEDED LATER TONIGHT.
OTHERWISE...SHOWERS AND THUNDERSTORMS ARE POSSIBLE AT EITHER SITE
TOMORROW AFTERNOON AND EVENING.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...LOCKHART
SHORT TERM...DR
LONG TERM...BRB
AVIATION...BRB
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
317 AM CDT Wed Aug 7 2013
...UPDATED LONG TERM...
.SYNOPSIS...
ISSUED AT 1229 AM CDT WED AUG 7 2013
At 00z Wednesday a +100kt 250mb jet extended from South Dakota
into the western great lakes. The right entrance region was
located near central Nebraska/northern Kansas. At the 500mb level
an upper level trough was located over eastern Montana and an
upper level ridge axis was located across the pacific northwest.
Further south over the southern plains an upper high was located
near the gulf coast of Texas and an upper level low/trough moved
northward out of Mexico into eastern Arizona. Convection that
developed across southwest Kansas near the Colorado border around
00z Wednesday was currently moving east/southeast across south
central Kansas at 05z. These storms appeared to located where the
better 850mb moisture, frontogenesis, and warm air advection were
occurring earlier this evening. Further north another area of
convection had developed during the evening hours from northeast
Colorado into western Nebraska. This a located near a surface
trough of low pressure and where better moist upslope flow was
present along with better mid level lapse rates. RAP also hinted
at a subtle upper level wave was located in this area at 00z.
&&
.SHORT TERM...(Today and tonight)
ISSUED AT 251 AM CDT WED AUG 7 2013
The NAM, RAP, GFS were all in decent agreement this morning with
moving an upper level trough across northern Kansas early this
morning. Based on the 06z location of this upper wave it appears
that an area of convection had developed ahead of this system
based on the composite radar loop. Given this and the timing of
the upper level trough will raise precipitation chances in the
north to at least high chance for early this morning. Further
south the chances for convection early will be less but still
given weak lift forecast across southwest Kansas will keep some
small pops going early today.
Convection should briefly taper off as the upper level trough
passes east of the area, however by the early afternoon the
chances for convection will begin to improve, especially across
far western and southwest Kansas where moist upslope flow is
expected and better afternoon instability and 0-6km shear is
forecast to be located. Convection will then increase in areal
coverage as it spreads east across the remainder of western Kansas
late today and overnight as the Arizona upper low/trough moves
east across New Mexico. Heavy rainfall will still be an issue
later today and overnight given the precipitable water content on
the Dodge City soundings at 1.42 inches at 00z Wednesday. Also
strong damaging winds and large hail will be possible from some
these storms late today and early tonight. The flood watch
currently in the effect still looks on track given several
opportunities of heavy precipitation later today through Thursday.
.LONG TERM...(Thursday through Tuesday)
ISSUED AT 315 AM CDT WED AUG 7 2013
A cool and wet period is forecast for the area with much above
average forecaster certainty for significant measurable rainfall
through thursday. The synoptic set up includes an already very moist
atmosphere across the central high plains, characterized by dew
points in the 60s and 70s. additionally, and upper high center over
the Southern Plains and Gulf region helping transport additional
pacific moisture poleward. the kinematic fields will include the
slow development of a Central Rockies through which will place
Western Kansas under a favorable positive vorticity and warm
advection region for maximum lift potential thursday. Additionally, a
surface/850 mb frontal zone will air in low level frontogenesis
adding to the QG component. These elements have given enough
confidence to raise precipitation chances into the categorical range
during the day 2 period. The slow nature of this existing wave will
create a fluid forecast situation . The jet streak will still leave
a broad right rear quadrant entrance region into Friday, and
thunderstorm cannot be ruled out through this period as well,
although the trend would be downward. During this period it is
likely that a widespread one to two inches of rain will fall over
the entire southwest and central Kansas region. Areas of higher rainfall
perhaps in excess of 5 inches are possible based on model run
totals, but with relatively low forecaster confidence with respect
to coverage.
From Friday and onward increased ridging along the High Plains
region will create a warming trend with opportunities for severe
weather producing MCS events into early next week.
&&
.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
ISSUED AT 1229 AM CDT WED AUG 7 2013
Models and guidance remains in decent agreement in keeping the
wind easterly across western Kansas overnight and Wednesday.
Boundary layer not as moist as the past few nights and with
stronger winds forecast just above the surface it currently
appears enough mixing will occur to prevent any significant
fog/status development. latest HRRR also suggesting a similar
solution. Convection over northeast Colorado will move
east/southeast and currently is expected to impact mainly the Hays
area around daybreak. Widespread convection will then once again
be possible by later today/early tonight across all of western Kansas.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 82 66 78 62 / 70 80 50 40
GCK 80 65 77 61 / 70 80 50 40
EHA 83 65 79 61 / 70 80 40 40
LBL 83 67 81 63 / 70 70 40 40
HYS 79 65 75 61 / 70 80 60 40
P28 85 69 81 66 / 70 80 50 40
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
FLOOD WATCH through Thursday afternoon FOR KSZ045-046-064>066-
079-081.
&&
$$
SYNOPSIS...BURGERT
SHORT TERM...BURGERT
LONG TERM...RUSSELL
AVIATION...BURGERT
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
254 AM CDT Wed Aug 7 2013
...UPDATED SHORT TERM DISCUSSION...
.SYNOPSIS...
ISSUED AT 1229 AM CDT WED AUG 7 2013
At 00z Wednesday a +100kt 250mb jet extended from South Dakota
into the western great lakes. The right entrance region was
located near central Nebraska/northern Kansas. At the 500mb level
an upper level trough was located over eastern Montana and an
upper level ridge axis was located across the pacific northwest.
Further south over the southern plains an upper high was located
near the gulf coast of Texas and an upper level low/trough moved
northward out of Mexico into eastern Arizona. Convection that
developed across southwest Kansas near the Colorado border around
00z Wednesday was currently moving east/southeast across south
central Kansas at 05z. These storms appeared to located where the
better 850mb moisture, frontogenesis, and warm air advection were
occurring earlier this evening. Further north another area of
convection had developed during the evening hours from northeast
Colorado into western Nebraska. This a located near a surface
trough of low pressure and where better moist upslope flow was
present along with better mid level lapse rates. RAP also hinted
at a subtle upper level wave was located in this area at 00z.
&&
.SHORT TERM...(Today and tonight)
ISSUED AT 251 AM CDT WED AUG 7 2013
The NAM, RAP, GFS were all in decent agreement this morning with
moving an upper level trough across northern Kansas early this
morning. Based on the 06z location of this upper wave it appears
that an area of convection had developed ahead of this system
based on the composite radar loop. Given this and the timing of
the upper level trough will raise precipitation chances in the
north to at least high chance for early this morning. Further
south the chances for convection early will be less but still
given weak lift forecast across southwest Kansas will keep some
small pops going early today.
Convection should briefly taper off as the upper level trough
passes east of the area, however by the early afternoon the
chances for convection will begin to improve, especially across
far western and southwest Kansas where moist upslope flow is
expected and better afternoon instability and 0-6km shear is
forecast to be located. Convection will then increase in areal
coverage as it spreads east across the remainder of western Kansas
late today and overnight as the Arizona upper low/trough moves
east across New Mexico. Heavy rainfall will still be an issue
later today and overnight given the precipitable water content on
the Dodge City soundings at 1.42 inches at 00z Wednesday. Also
strong damaging winds and large hail will be possible from some
these storms late today and early tonight. The flood watch
currently in the effect still looks on track given several
opportunities of heavy precipitation later today through Thursday.
.LONG TERM...(Wednesday night through Tuesday)
ISSUED AT 320 PM CDT TUE AUG 6 2013
Not too much has changed in the extended forecast, except rain
chances have increased in the Thursday time frame. 80% categorical
shower and thunderstorms chances late Wednesday night and early
Thursday morning will taper to 50 to 60 percent likely chances by
Thursday day break, and stay about there through the day Thursday.
a meandering surface front across southwestern Kansas will combine
with an upper level short wave moving east across western Kansas, to
bring more substantial rainfall to southwestern Kansas Thursday.
The upper wave will move into central Kansas late Thursday night,
and precipitation chances will taper even lower into the 40 percent
range Thursday night, and diminish downward to 15 percent by Friday
afternoon. Once that upper wave is to our east, another will be
tracking from the west, nearly on it`s heal. Saturday will see
scattered 20 to 30 percent rain chances, and low widely scattered
showers and thunderstorm trend will persist into Sunday night. On
Monday, chance pops will cover most all of our forecast area of
southwestern Kansas, as the larger upper wave will be crossing
then. Precipitation chances will shift east Monday night and
Tuesday, and felt slight chances were enough for now out in the day
8 time frame.
For temperatures, Thursday will start out "cool" with highs int he
upper 70s across out northern 3/4ths of the forecast area, and in
the lower to mid 80d along the Oklahoma border. This will mainly be
due to a cold front slipping southward through our area, but also
due to clouds and precipitation being plentiful. Clouds will be
slow to break up and clear on Friday, so temperatures will respond
to the lower 80s to middle 80s. A warming trend will ensue through
Sunday, when max temps will rise into the lower to middle 90s. Max
temps will remain in that 90s range Sunday through Tuesday.
Minimum temperatures will range in the lower to middle 60s from
Thursday through Sunday, then rise a little into the middle 60s to
lower 70s Monday through Tuesday.
&&
.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
ISSUED AT 1229 AM CDT WED AUG 7 2013
Models and guidance remains in decent agreement in keeping the
wind easterly across western Kansas overnight and Wednesday.
Boundary layer not as moist as the past few nights and with
stronger winds forecast just above the surface it currently
appears enough mixing will occur to prevent any significant
fog/status development. latest HRRR also suggesting a similar
solution. Convection over northeast Colorado will move
east/southeast and currently is expected to impact mainly the Hays
area around daybreak. Widespread convection will then once again
be possible by later today/early tonight across all of western Kansas.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 82 66 78 62 / 70 80 50 40
GCK 80 65 77 61 / 70 80 50 40
EHA 83 65 79 61 / 70 80 40 40
LBL 83 67 81 63 / 70 70 40 40
HYS 79 65 75 61 / 70 80 60 40
P28 85 69 81 66 / 70 80 50 40
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
FLOOD WATCH through Thursday afternoon FOR KSZ045-046-064>066-
079-081.
&&
$$
SYNOPSIS...BURGERT
SHORT TERM...BURGERT
LONG TERM...BURKE
AVIATION...BURGERT
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1156 PM MDT TUE AUG 6 2013
.UPDATE...
ISSUED AT 745 PM MDT TUE AUG 6 2013
UPDATED TO REMOVE THE CONVECTIVE WATCH AND ACCOUNT FOR DECREASING
THUNDERSTORM COVERAGE ACROSS THE SOUTH AND ADDITIONAL
THUNDERSTORMS MOVING ACROSS NORTHEAST COLORADO INTO FAR SOUTHWEST
NEBRASKA AND FAR NORTHWEST KANSAS.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 222 PM MDT TUE AUG 6 2013
LATEST WV IMAGERY AND RAP ANALYSIS SHOWS NW FLOW STILL IN PLACE
ACROSS THE NORTHERN AND CENTRAL CONUS...WITH A RIDGE CENTERED OVER
TEXAS AND A WEAKENED CLOSED LOW OVER SOUTHERN ARIZONA. A VERY
MOIST/UNSTABLE AIRMASS REMAINS IN PLACE OVER OUR CWA WITH TD VALUES
ACROSS NW KANSAS IN THE MID 60S TO LOW 70S...AND SB CAPE VALUES IN
THE 2000-4000 J/KG RANGE FROM THE WEST TO THE EAST. A SURFACE
TROUGH IS CURRENTLY CENTERED ALONG THE KS/CO BORDER...WITH LOWER
TD VALUES AND MUCH MORE STABLE AIRMASS TO THE WEST OF THIS
FEATURE.
THUNDERSTORMS HAVE ALREADY DEVELOPED ALONG THIS TROUGH AXIS
IN OUR FAR SW CWA. I WOULD EXPECT ADDITIONAL THUNDERSTORM
ACTIVITY TO INITIATE ALONG AND EAST OF THIS FEATURE THROUGH THIS
AFTERNOON AND EVENING. LATEST HRRR INDICATED ACTIVITY FORMING AHEAD OF
THIS AXIS AND FORMING INTO A CLUSTER/LINE AND SHIFTING TO THE
SOUTH AND EAST. BASED ON NAM/GFS SUPPORTING BETTER COVERAGE IN THE
SOUTH...WHICH IS IN LINE WITH SHORT RANGE GUIDANCE I KEPT THIS
TREND. A COLD FRONT WILL APPROACH THE CWA TONIGHT...WITH ELEVATED
INSTABILITY/GOOD MOISTURE LINGERING I DECIDED TO KEEP THUNDERSTORM
MENTION THROUGH THE NIGHT. CONSIDERING STORM MOTION WITH
INDIVIDUAL CELLS AND MOISTURE AVAILABILITY I AM CONCERNED WE COULD
SEE LOCALIZED FLASH FLOODING THIS AFTERNOON/EVENING IN ADDITION TO
SEVERE HAIL/WIND THREAT. COVERAGE IS A QUESTION THOUGH...WITH ANY
CLUSTER/LINE LIKELY BEGINNING TO PROPAGATE QUICKER AS IT FORMS A
COLD POOL IN OUR SOUTH. AS A RESULT WE MAY NOT ACTUALLY SEE AS
WIDESPREAD OF A THREAT OF FLASH FLOODING TODAY/TONIGHT.
WEDNESDAY...COLD FRONT WILL DROP SOUTH OF OUR CWA AND BE NEAR THE
KS/OK BORDER BY LATE WED AFTERNOON. DEEP MOIST EASTERLY FLOW
ALONG/NORTH OF THIS FEATURE COMBINED WITH INCREASING LARGE SCALE
ASCENT WILL SUPPORT NUMEROUS TO WIDESPREAD SHOWERS/THUNDERSTORMS
ACROSS OUR SOUTHERN CWA. I AM CONCERNED THAT THE BEST COVERAGE MAY
BE TIED TO THE FRONT...WHICH WOULD PUT BETTER COVERAGE SOUTH OF OUR
CWA. HOWEVER THERE IS ENOUGH MOISTURE/FORCING ALOFT TO SUPPORT
HIGHER POPS ACROSS OUR SOUTHERN CWA IN THE AFTERNOON. A RESULT OF
THICK CLOUD COVER AND CAA THROUGH THE DAY WILL BE HIGH TEMPERATURES
WELL BELOW NORMAL (UPPER 60S TO MID 70S). PREVIOUS FORECAST HAD THIS
COOLER TREND...SO ONLY MINOR ADJUSTMENTS MADE. WHILE WE MAY NEED A
FLASH FLOOD WATCH FOR WED AFTERNOON DUE TO POSSIBLE TRAINING AND
WIDESPREAD HEAVY RAIN COVERAGE IN THE SOUTH...I FELT IT WAS BEST TO
CONCENTRATE PUBLIC ATTENTION ON ONGOING THUNDERSTORMS THIS
AFTERNOON/EVENING TO AVOID CONFUSION. WE MAY NEED TO ISSUE A WATCH
ON OVERNIGHT SHIFTS IF IT LOOKS LIKE OUR SOUTHERN CWA WILL REMAIN
FAVORABLE FOR A LARGE SCALE FLASH FLOOD THREAT.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 246 PM MDT TUE AUG 6 2013
FOR WEDNESDAY NIGHT THROUGH THURSDAY NIGHT THE UPPER LEVEL WEATHER
PATTERN WILL REMAIN LARGELY UNCHANGED. AN UPPER LEVEL SHORT WAVE
TROUGH WILL MOVE OVER THE AREA WEDNESDAY NIGHT AND SLOWLY GLIDE
EASTWARD ACROSS THE AREA WITH ANOTHER ONE FOLLOWING IT OVER THE AREA
THURSDAY. WITH THE MID THROUGH UPPER LEVELS NEARLY TO TOTALLY
SATURATED AND THE RIGHT ENTRANCE OF THE 300MB JET OVER THE AREA AS
THESE TROUGHS MOVE THROUGH...AM THINKING THERE SHOULD BE A GOOD
CHANCE FOR SCATTERED TO WIDESPREAD RAINFALL DEVELOPMENT. THE BEST
AREA FOR PRECIP. CHANCES LOOKS TO BE OVER THE SOUTH HALF WHERE THE
BETTER FORCING AND LIFT WILL BE. PRECIP. CHANCES TAPER OFF THURSDAY
NIGHT FROM WEST TO EAST AS THE UPPER LEVEL TROUGH MOVES OUT OF THE
AREA AND DRIER AIR MOVES IN BEHIND IT. WEDNESDAY EVENING LOOKS TO
BE THE BEST CHANCE FOR SEVERE STORM DEVELOPMENT DUE TO 0-6KM SHEAR
OF 30-50KTS. HOWEVER ANY SEVERE STORMS THAT DEVELOP SHOULD REMAIN
CONFINED TO THE WESTERN AND SOUTHERN FRINGES OF THE AREA WHERE THE
BEST INSTABILITY WILL BE LOCATED. HEAVY RAINFALL WILL BE THE
PREDOMINANT THREAT DURING THIS TIMEFRAME DUE TO STORM MOTIONS OF
5-10KTS. A FLASH FLOOD WATCH WILL LIKELY BE NEEDED FROM WEDNESDAY
THROUGH THURSDAY MORNING FOR THE SOUTHERN TWO ROWS OF COUNTIES WHERE
STORM COVERAGE WILL BE MOST WIDESPREAD. AFTER SOME DISCUSSION WILL
HOLD OFF ISSUING THE WATCH FOR NOW TO PREVENT CONFUSION WITH ANY POTENTIAL
FLOODING THREAT FROM TODAY/S STORM ACTIVITY.
FOR FRIDAY THROUGH TUESDAY THE UPPER LEVEL RIDGE OVER THE SOUTHWEST
CONUS WILL BUILD A BIT FURTHER NORTH...WITH THE NORTHERN PERIPHERY
OF THE RIDGE OVER THE AREA. MULTIPLE UPPER LEVEL SHORT WAVE TROUGHS
WILL MOVE ACROSS THE AREA DURING THIS TIME CAUSING THERE TO BE
PRECIP. CHANCES FOR NEARLY EVERY DAY. MEANWHILE THE WEAK FRONT THAT
HAS BEEN WEST OF THE AREA WILL MOVE EAST ACROSS THE AREA DURING THE
WEEKEND INTO EARLY NEXT WEEK. AS A RESULT TEMPERATURES WILL RETURN
TO NORMAL.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1148 PM MDT TUE AUG 6 2013
INITIAL CONCERNS ARE ONGOING CONVECTION TO THE WEST OF BOTH TAF
SITES. GLD WILL EXPERIENCE A SHIFT IN WIND DIRECTION AND INCREASE
IN SPEEDS AS A RESULT OF AN OUTFLOW BOUNDARY SHORTLY AFTER 06Z.
THUNDERSTORMS SHOULD DECREASE OVER THE NEXT FEW HOURS. OTHER
CONCERNS FOR GLD WAS A BRIEF REDUCTION OF VISIBILITY LAST HOUR.
THIS APPEARS TO BE TEMPORARY. FURTHER REDUCTIONS ARE UNLIKELY
ESPECIALLY AFTER THUNDERSTORM OUTFLOW BOUNDARY PASSES THROUGH. FOR
MCCOOK...THUNDERSTORMS MAY BE IN THE VICINITY BY AROUND 08Z. SOME
FOG COULD FORM AT MCK BUT NEARBY THUNDERSTORMS AND RESULTANT
OUTFLOW MAY KEEP WINDS UP ENOUGH TO PREVENT THIS. TRENDS WILL BE
MONITORED AND AMENDMENTS MAY BE NEEDED LATER TONIGHT.
OTHERWISE...SHOWERS AND THUNDERSTORMS ARE POSSIBLE AT EITHER SITE
TOMORROW AFTERNOON AND EVENING.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...LOCKHART
SHORT TERM...DR
LONG TERM...JTL
AVIATION...BRB
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1240 AM CDT Wed Aug 7 2013
...UPDATED SYNOPSIS AND AVIATION...
.SYNOPSIS...
ISSUED AT 1229 AM CDT WED AUG 7 2013
At 00z Wednesday a +100kt 250mb jet extended from South Dakota
into the western great lakes. The right entrance region was
located near central Nebraska/northern Kansas. At the 500mb level
an upper level trough was located over eastern Montana and an
upper level ridge axis was located across the pacific northwest.
Further south over the southern plains an upper high was located
near the gulf coast of Texas and an upper level low/trough moved
northward out of Mexico into eastern Arizona. Convection that
developed across southwest Kansas near the Colorado border around
00z Wednesday was currently moving east/southeast across south
central Kansas at 05z. These storms appeared to located where the
better 850mb moisture, frontogenesis, and warm air advection were
occurring earlier this evening. Further north another area of
convection had developed during the evening hours from northeast
Colorado into western Nebraska. This a located near a surface
trough of low pressure and where better moist upslope flow was
present along with better mid level lapse rates. RAP also hinted
at a subtle upper level wave was located in this area at 00z.
&&
.SHORT TERM...(This evening through Wednesday) ISSUED AT 235 PM CDT
TUE AUG 6 2013
The wet weather pattern continues as weak disturbances move around
the periphery of an upper level high centered across Texas. The mid
and lower levels of the atmosphere will be quite moist for this time
of the year with PWAT values over 1.25 inches across western Kansas
through the short term period. Thunderstorms are expected to form
across far western Kansas this afternoon and spread eastward through
the evening. Some of these storms may become severe with large hail
and damaging winds being the main concern. A few other storms could
form across the KS/OK border where a stationary front is located.
Thunderstorm chances continue through midnight with decreasing
coverage during the early morning hours. If storms train over the
same location for an extended period of time, flooding could become
a concern. Clouds will increase this afternoon with mostly cloudy
skies expected overnight. Winds at the surface will generally be
from the east to east southeast which will allow upslope flow to
occur across western Kansas. With mostly cloudy skies overnight,
lows tonight are expected to range from the upper 60s across west
central Kansas to lower 70s across south central Kansas.
Another lull in the action is expected Wednesday morning as the
thunderstorms the night before moves into eastern Kansas. Meanwhile,
a surface cold front is progged to move through Nebraska in the
morning and into northern Kansas by the afternoon. Another round of
thunderstorms are forecasted to form across eastern Colorado in the
afternoon and move into western Kansas. A few of these storms could
also become severe with strong winds and large hail being the main
concern. Once again, if storms train over the same location for an
extended period of time, flooding could become a concern. Winds will
continue to be from the east with the exception of areas behind the
aforementioned front where northeast winds will be observed. Cooler
temperatures are expected tomorrow with highs ranging from the mid
70s across west central Kansas to mid 80s across south central
Kansas.
.LONG TERM...(Wednesday night through Tuesday)
ISSUED AT 320 PM CDT TUE AUG 6 2013
Not too much has changed in the extended forecast, except rain
chances have increased in the Thursday time frame. 80% categorical
shower and thunderstorms chances late Wednesday night and early
Thursday morning will taper to 50 to 60 percent likely chances by
Thursday day break, and stay about there through the day Thursday.
a meandering surface front across southwestern Kansas will combine
with an upper level short wave moving east across western Kansas, to
bring more substantial rainfall to southwestern Kansas Thursday.
The upper wave will move into central Kansas late Thursday night,
and precipitation chances will taper even lower into the 40 percent
range Thursday night, and diminish downward to 15 percent by Friday
afternoon. Once that upper wave is to our east, another will be
tracking from the west, nearly on it`s heal. Saturday will see
scattered 20 to 30 percent rain chances, and low widely scattered
showers and thunderstorm trend will persist into Sunday night. On
Monday, chance pops will cover most all of our forecast area of
southwestern Kansas, as the larger upper wave will be crossing
then. Precipitation chances will shift east Monday night and
Tuesday, and felt slight chances were enough for now out in the day
8 time frame.
For temperatures, Thursday will start out "cool" with highs int he
upper 70s across out northern 3/4ths of the forecast area, and in
the lower to mid 80d along the Oklahoma border. This will mainly be
due to a cold front slipping southward through our area, but also
due to clouds and precipitation being plentiful. Clouds will be
slow to break up and clear on Friday, so temperatures will respond
to the lower 80s to middle 80s. A warming trend will ensue through
Sunday, when max temps will rise into the lower to middle 90s. Max
temps will remain in that 90s range Sunday through Tuesday.
Minimum temperatures will range in the lower to middle 60s from
Thursday through Sunday, then rise a little into the middle 60s to
lower 70s Monday through Tuesday.
&&
.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
ISSUED AT 1229 AM CDT WED AUG 7 2013
Models and guidance remains in decent agreement in keeping the
wind easterly across western Kansas overnight and Wednesday.
Boundary layer not as moist as the past few nights and with
stronger winds forecast just above the surface it currently
appears enough mixing will occur to prevent any significant
fog/status development. latest HRRR also suggesting a similar
solution. Convection over northeast Colorado will move
east/southeast and currently is expected to impact mainly the Hays
area around daybreak. Widespread convection will then once again
be possible by later today/early tonight across all of western Kansas.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 66 78 62 80 / 80 50 40 40
GCK 65 77 61 81 / 80 50 40 40
EHA 64 79 61 83 / 80 40 40 40
LBL 66 81 63 82 / 70 40 40 40
HYS 64 75 61 80 / 80 60 40 40
P28 69 81 66 82 / 80 50 40 40
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
FLOOD WATCH through Thursday afternoon FOR KSZ045-046-064>066-
079-081.
&&
$$
SYNOPSIS...BURGERT
SHORT TERM...HOVORKA_42
LONG TERM...BURKE
AVIATION...BURGERT
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1215 AM CDT Wed Aug 7 2013
.UPDATE...
ISSUED AT 1131 PM CDT TUE AUG 6 2013
STORMS ALONG THE FRONT HAVE DIMINISHED ACROSS SOUTH CENTRAL NE.
DECIDED TO REDUCE POPS ACROSS THE NORTHERN COUNTIES TO SLIGHT FOR
THE REMAINDER OF TONIGHT.
MCS NOW MOVING ACROSS SOUTH CENTRAL KS. THE NORTHERN EDGE OF THE
MCS MAY CLIP THE SOUTHERN COUNTIES OF THE CWA...SOUTH OF I-70. PW
ON THE 00Z TOP SOUNDING WAS 1.98 INCHES...SO THERE MAY BE SOME
HEAVY RAINFALL IF THE MCS DOES CLIP THE SOUTHERN COUNTIES. ALSO
THESE AREAS HAVE RECEIVED A LOT OF RAINFALL OVER THE PAST
WEEK...THUS ANY ADDITIONAL HEAVY RAINFALL WILL RESULT IN RUNOFF AND
POTENTIAL FLOODING. I KEPT LIKELY POPS FOR THE EARLY MORNING HOURS
ALONG AND SOUTH OF THE I-35 CORRIDOR.
&&
.SHORT TERM...(TONIGHT THROUGH WEDNESDAY) ISSUED AT 319 PM CDT TUE
AUG 6 2013
HRRR model seems to have predicted the location of the developing MCS
across southwest Kansas, though the speed of propagation depicted
by the HRRR model of this MCS looks to be about 2 to 3 hours too
fast. the the northern edge of the MCS or leftover complex of
thunderstorms may move east across the south central Kansas into
the southern counties of the CWA after 100 AM. If the northern
edge of this complex of thunderstorms actually moves across the
southern counties of the CWA then there may be periods of heavy
rainfall during the early morning hours generally south of an
Abilene, to Ottawa, line given PW values of 1.8 inches.
There may also be isolated to scattered thunderstorms developing
along a cold front in south central NE that may move southeast
into portions of north central and northeast Kansas after
Midnight. Isolated showers and thunderstorm may develop along or
just north of an outflow boundary along I-70 across central Kansas
and move southeast across portions the southern counties of the
CWA through the evening hours.
.Short term...(This evening through Wednesday) Issued AT 319 PM CDT
Tue Aug 6 2013
At 3 PM on Wednesday, a warm and moist airmass remained in
place across all of Kansas. A warm front remained situated along
the Kansas Oklahoma border while a weak outflow boundary remnant
from early morning storms had stalled in northern Kansas. The
other feature of note is a cold front moving into Nebraska from
SD. Temperatures around 90 and dewpoints in the low to mid 70s
were leading to MLCAPE values across much of the area up to 4000
J/KG. Upslope flow in western Kansas along with another weak short
wave trough has initiated thunderstorms near the Colorado
border... similar to Monday afternoon. This western KS activity is
expected to build east and southeast into south central Kansas
again today, but as the low level jet increases this evening
expect the complex to build more northeast. The HRRR, which has
performed rather well in the past few days, suggests that this
convective complex will be enhanced by additional low level jet
driven convection and will track from south central Kansas up the
Kansas turnpike and across east central Kansas. A few of these
individual storms may be strong with damaging winds possible
mainly near and south of the turnpike. Heavy rain will also be
likely, but the heaviest elements are expected to be progressive
in nature and widespread heavy rain is not expected at this time,
although isolated flooding will be possible. Additional storms may
move out of Nebraska along the cold front after midnight, and
could also be strong as they enter Kansas.
There is the potential for multiple fronts/boundaries to be in place
across the area on Wednesday, although the main cold front should
also slowly sink into Kansas. These boundaries may serve as a focus
for scattered storms throughout the day, but expect most areas to be
dry during the daylight hours. Temperatures will be a bit cooler,
but the very moist airmass will remain in place for much of the area.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 319 PM CDT
TUE AUG 6 2013
Wednesday evening through Friday...
Currently watching the next potent shortwave trough currently
rotating over far southern Arizona at this hour. This wave will
bring the highest chances for convective rainfall beginning
Wednesday evening. Timing with this wave continues to slightly vary
between each model run unfortunately leading to some uncertainty as
to when heaviest rainfall will occur. Smaller embedded troughs
ejected from the main shortwave could bring scattered showers and
thunderstorms early on Wednesday evening before an mcs develops over
western KS and traverses east through Kansas early Thursday. Highest
chances for rainfall were emphasized mainly along and south of
Interstate 70. Strong isentropic lift maximizes from 305 to 315k
surfaces with a strong baroclinc zone in place suggesting widespread
moderate to heavy rainfall. Precipitable water values agree with
this scenario reaching over 2.25 inches...two standard deviations
above normal. High rainfall rates may quickly lead to flash flooding
and river flooding concerns for much of the cwa as current flash
flood guidance only holds around 2 inches of rainfall in a three hour
period. A flood watch will need to be considered in the upcoming
shifts for this period. The main wave slowly lifts northeast
Thursday evening with another possible mcs developing along and
behind a cold front. GFS and ECMWF both indicate a complex
developing over western Nebraska tracking southeast into northeast
Kansas into Friday with precip slowly tapering off west to east as
subsidence builds in the late afternoon.
Temperatures were lowered a few degrees on Thursday afternoon as
progged rainfall throughout the day with no cloud clearing expected
should hold readings in the middle to upper 70s. Drier air entering
from Nebraska Friday will clear out the stratus clouds with highs in
the low 80s.
Friday evening through Tuesday...
Subsidence building behind the wave should bring a temporary lull in
the rain Friday evening through Saturday afternoon. Run to run
consistency between the GFS and ECWMF contains plenty of
discrepancies but overall pattern characterizes the upper ridge over
the western conus building once again with northwest flow increasing
over the area Sunday. Periods of off and on showers and
thunderstorms begin on Sunday afternoon and continue through Tuesday
as a series of shortwave troughs translate along the edge of the
ridge. High are generally in the mid to upper 80s...combined with
dewpoints in the upper 60s should continue with the warm and muggy
conditions.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z Wednesday NIGHT)
ISSUED AT 1209 AM CDT WED AUG 7 2013
A complex of storms will pass south of the TAF sites this morning,
through some scattered thunderstorms may develop northward across
the TAF sites after 6Z and last through sunrise. Expect VFR
conditions through most of the the period. There may be isolated to
scattered thunderstorms developing at the TAF sites late this
afternoon and through the evening hours of Wednesday.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GARGAN
SHORT TERM...BARJENBRUCH
LONG TERM...BOWEN
AVIATION...GARGAN
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1148 PM EDT Thu Aug 8 2013
...Forecast Update...
Issued at 1145 PM EDT Thu Aug 8 2013
One more quick update to match up areas of rain on 88D with the
forecast. Theta-E ridge axis now is focused along where the new
cells are developing in our southwest forecast area. Storms farther
north are progressing east nicely, limiting rainfall totals for now.
Issued at 944 PM EDT Thu Aug 8 2013
Did another quick update to increase PoP chances across southern
Indiana and far northern Kentucky for later this evening. Cluster
of ongoing showers and storms across southern Indiana is drifting a
little more southward now, with some backbuilding on the
southwestern flank. Extrapolated radar imagery suggests that this
could clip areas all the way south toward the Ohio River later this
evening. These showers and storms could affect the Louisville Metro
area around midnight EDT.
Secondary cluster of storms across northwest TN continues to trek
northeastward and is showing signs of gusting out to the northeast.
If these storms hold together, they could affect far southern
Kentucky after midnight as well.
Not much development off to the west at this time. However, latest
data continues to suggest that additional storms may develop to our
west and then head through central Kentucky overnight. It appears
that the models may be trying to develop convection in associated
with the nocturnal low-level jet axis. For now, have backed off
PoPs slightly in central Kentucky until after midnight and then have
let PoPs ramp up late. Rest of the forecast elements look good at
this time.
Update issued at 820 PM EDT Thu Aug 8 2013
Did a quick update to scale back precipitation chances for the next
few hours across much of Kentucky. Vorticity lobe continues to trek
eastward across Indiana this evening. Convection along the southern
edge of this boundary never really moved southward...but rather
eastward and looks to stay along and north of the I-64 corridor for
the next few hours. The best chances of rainfall in the near term
will be across our north edges of southern Indiana counties.
Secondary cluster of strong thunderstorms has rapidly intensified
across far eastern Arkansas and west Tennessee. This activity
continues to trek eastward and may affect the extreme southern
portions of our area toward the late evening hours. Additional
storms across east-central MO/IL are trying to develop. Latest
model data suggests this activity will further develop this evening
and then push into the region overnight. Will continue to go with
the higher PoPs for the later overnight period, but continue to
monitor the latest convective trends throughout the evening.
Update issued at 648 PM EDT Thu Aug 8 2013
Cluster of light to moderate rain showers continues to trek eastward
across portions of north-central Kentucky. This activity is
expected to continue for the next several hours, but should weaken
as it heads toward the I-75 corridor. More strongly forced
convection is rapidly developing on the southern side of a vorticity
max pushing eastward into Indiana. Storms are forming along a
differential heating and wind shift axis across southern Illinois.
This activity should continue to develop and track eastward along
the I-64 corridor this evening. Latest NAM and HRRR runs suggest
that this would impact north-central Kentucky during the overnight
period. Secondary area of storms is developing over southern MO and
northern AR, this activity will also head east, but may stay just
south of the forecast area late tonight.
With this update, have increased PoPs for the next few hours across
the central portions of the forecast area with the batch of
light-moderate rain moving through. Will continue to ramp up PoPs
tonight as the cluster of storms out to the west heads eastward into
the Ohio Valley.
.SHORT TERM (Now through Friday Night)...
Issued at 315 PM EDT Thu Aug 8 2013
An obstructed blocky flow continues over Canada late today with an
elongated west to east orientated 500mb low over Ontario and Quebec.
Farther south, a moderate westerly flow continues over the northern
Ohio Valley. Precipitable water values of near two inches or more
will continue through mid-day Friday, indicative of a tropical
airmass.
Quite a bit uncertainty still exists about where exactly convection
develops this evening. An circulation left over from last night`s
convection is now moving east northeast just to the south of St
Louis. This feature will move over southern Indiana late this
evening. This feature is supporting a cluster of thunderstorms now
moving east over western Kentucky. These storms are moving into an
unstable airmass southwest of Kentucky and should hold together
through this evening. Therefore, think storms late this afternoon
and early evening will become most numerous across west central
Kentucky, west of Interstate 65 and mostly to the south of
Interstate 64 across southern Indiana. A second area of convection
may drop south into south central Indiana late this evening. These
northern storms will form along a cold front slowly sagging south
across central Indiana. Will go likely for areas in Kentucky west of
Interstate 65 with scattered wording elsewhere.
Last night isolated storms over the Bluegrass produced very isolated
torrential rainfall amounts and flooding. This same scenario may play itself
out again tonight. Across south central Kentucky, localized heavy
rain and possible flooding are again possible in a few spots.
For Friday, a nearly stationary front will lie across southern
Indiana, nearly parallel to the Ohio River, any thunderstorm
development will highly depend on the location of any residual cloud
cover and outflow boundaries from overnight convection. Our best
moisture and convergence will lie over southern portions of our
Commonwealth. Slightly drier air will slowly filter in across
southern Indiana, limiting convective coverage there. Will continue
likely pops across southern Kentucky during the day Friday. Think
that any scattered storms will diminish across the north late
Friday, while hanging on near Tennessee.
Tonight will stay humid and muggy, with lows in the lower 70s, highs
Friday will reach the mid to upper 80s.
.LONG TERM (Saturday through Thursday)...
Issued at 309 PM EDT Thu Aug 8 2013
Quasi-stationary boundary laid out across the commonwealth will be
starting off this forecast period, allowing for the primary focus
for convection to be limited to southern portions of KY. Have
trended back PoPs for the northern half of the forecast area as such
since surface winds will have begun to back to the north by this
point, assuming the general deterministic model consensus holds
true. With the loss of daytime heating and as the front slowly
slides off to the south and east, have gone dry for the early
morning hours on Sunday. Couldn`t completely remove PoPs out of the
forecast for the afternoon hours as a surface low riding along the
frontal boundary traverses across from west to east, once again
serving as a focus for renewed convection chances as surface high
pressure centered over the southern Great Lakes fights for control
over us. This fight, however, is very short lived as the high moves
off toward the East Coast and the next frontal boundary approaches
the Ohio Valley. This front is seemingly much faster with strong
Canadian high pressure pushing it southward from behind. What this
translates to for us is a continued unsettled period from Monday
through Tuesday night. By Wednesday, am hopeful that the boundary
will be south of the TN border, although the 12Z GFS tries to keep
the southern tier of counties wet through Wednesday night. Even if
the timing ends up being slightly off, the end result will be the
same for all of us: clearing skies, a much drier airmass, and cool
temperatures for this time of year.
Speaking of temperatures, we`ll see highs ranging from the lower to
upper 80s throughout the entire period with the warmest day looking
to be Monday and the coolest day on Thursday. Dewpoints will keep it
muggy from this weekend through mid-week before a noticeable
difference comes in by Wednesday-Thursday. Lows will be near normal
Saturday night through Tuesday night, dropping off to below normal
by Wednesday night. Looking at 850mb anomalous temps on NCEP`s
ensemble, the cool temps are depicted to prevail under the
aforementioned high for much of the end of next week.
&&
.AVIATION (00Z TAF Update)...
Issued at 716 PM EDT Thu Aug 8 2013
The TAF sites are staying dry at this point in the evening, however
there is a chance that a cluster of thunderstorms developing over south
central Illinois may impact SDF and LEX late this evening and
overnight. At this point, the bulk of the showers and storms should
stay across southern Indiana, although there is potential that the
southern end of the cluster could impact SDF/LEX. If this were to
happen it would likely be around the Midnight - 2 AM EDT time frame
at SDF, and around 2 - 4 AM EDT at LEX. For now, will stay more
optimistic at these locations, however it should be noted that if
the storms do impact the TAF sites, brief IFR visibilities and at
least MVFR ceilings will be likely. BWG also stands a shot at seeing
showers and storm overnight, however precipitation should hold off
until after 1 AM CDT, so will just be general with VCTS in the
forecast until we can get a better handle. Otherwise, ceilings
should stay VFR outside any storms. A better chance for MVFR may
occur again around dawn.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
Updates........RJS/MJ
Short Term.....JSD
Long Term......lg
Aviation.......BJS
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
945 PM EDT Thu Aug 8 2013
...Forecast Update...
Issued at 944 PM EDT Thu Aug 8 2013
Did another quick update to increase PoP chances across southern
Indiana and far northern Kentucky for later this evening. Cluster
of ongoing showers and storms across southern Indiana is drifting a
little more southward now, with some backbuilding on the
southwestern flank. Extrapolated radar imagery suggests that this
could clip areas all the way south toward the Ohio River later this
evening. These showers and storms could affect the Louisville Metro
area around midnight EDT.
Secondary cluster of storms across northwest TN continues to trek
northeastward and is showing signs of gusting out to the northeast.
If these storms hold together, they could affect far southern
Kentucky after midnight as well.
Not much development off to the west at this time. However, latest
data continues to suggest that additional storms may develop to our
west and then head through central Kentucky overnight. It appears
that the models may be trying to develop convection in associated
with the nocturnal low-level jet axis. For now, have backed off
PoPs slightly in central Kentucky until after midnight and then have
let PoPs ramp up late. Rest of the forecast elements look good at
this time.
Update issued at 820 PM EDT Thu Aug 8 2013
Did a quick update to scale back precipitation chances for the next
few hours across much of Kentucky. Vorticity lobe continues to trek
eastward across Indiana this evening. Convection along the southern
edge of this boundary never really moved southward...but rather
eastward and looks to stay along and north of the I-64 corridor for
the next few hours. The best chances of rainfall in the near term
will be across our north edges of southern Indiana counties.
Secondary cluster of strong thunderstorms has rapidly intensified
across far eastern Arkansas and west Tennessee. This activity
continues to trek eastward and may affect the extreme southern
portions of our area toward the late evening hours. Additional
storms across east-central MO/IL are trying to develop. Latest
model data suggests this activity will further develop this evening
and then push into the region overnight. Will continue to go with
the higher PoPs for the later overnight period, but continue to
monitor the latest convective trends throughout the evening.
Update issued at 648 PM EDT Thu Aug 8 2013
Cluster of light to moderate rain showers continues to trek eastward
across portions of north-central Kentucky. This activity is
expected to continue for the next several hours, but should weaken
as it heads toward the I-75 corridor. More strongly forced
convection is rapidly developing on the southern side of a vorticity
max pushing eastward into Indiana. Storms are forming along a
differential heating and wind shift axis across southern Illinois.
This activity should continue to develop and track eastward along
the I-64 corridor this evening. Latest NAM and HRRR runs suggest
that this would impact north-central Kentucky during the overnight
period. Secondary area of storms is developing over southern MO and
northern AR, this activity will also head east, but may stay just
south of the forecast area late tonight.
With this update, have increased PoPs for the next few hours across
the central portions of the forecast area with the batch of
light-moderate rain moving through. Will continue to ramp up PoPs
tonight as the cluster of storms out to the west heads eastward into
the Ohio Valley.
.SHORT TERM (Now through Friday Night)...
Issued at 315 PM EDT Thu Aug 8 2013
An obstructed blocky flow continues over Canada late today with an
elongated west to east orientated 500mb low over Ontario and Quebec.
Farther south, a moderate westerly flow continues over the northern
Ohio Valley. Precipitable water values of near two inches or more
will continue through mid-day Friday, indicative of a tropical
airmass.
Quite a bit uncertainty still exists about where exactly convection
develops this evening. An circulation left over from last night`s
convection is now moving east northeast just to the south of St
Louis. This feature will move over southern Indiana late this
evening. This feature is supporting a cluster of thunderstorms now
moving east over western Kentucky. These storms are moving into an
unstable airmass southwest of Kentucky and should hold together
through this evening. Therefore, think storms late this afternoon
and early evening will become most numerous across west central
Kentucky, west of Interstate 65 and mostly to the south of
Interstate 64 across southern Indiana. A second area of convection
may drop south into south central Indiana late this evening. These
northern storms will form along a cold front slowly sagging south
across central Indiana. Will go likely for areas in Kentucky west of
Interstate 65 with scattered wording elsewhere.
Last night isolated storms over the Bluegrass produced very isolated
torrential rainfall amounts and flooding. This same scenario may play itself
out again tonight. Across south central Kentucky, localized heavy
rain and possible flooding are again possible in a few spots.
For Friday, a nearly stationary front will lie across southern
Indiana, nearly parallel to the Ohio River, any thunderstorm
development will highly depend on the location of any residual cloud
cover and outflow boundaries from overnight convection. Our best
moisture and convergence will lie over southern portions of our
Commonwealth. Slightly drier air will slowly filter in across
southern Indiana, limiting convective coverage there. Will continue
likely pops across southern Kentucky during the day Friday. Think
that any scattered storms will diminish across the north late
Friday, while hanging on near Tennessee.
Tonight will stay humid and muggy, with lows in the lower 70s, highs
Friday will reach the mid to upper 80s.
.LONG TERM (Saturday through Thursday)...
Issued at 309 PM EDT Thu Aug 8 2013
Quasi-stationary boundary laid out across the commonwealth will be
starting off this forecast period, allowing for the primary focus
for convection to be limited to southern portions of KY. Have
trended back PoPs for the northern half of the forecast area as such
since surface winds will have begun to back to the north by this
point, assuming the general deterministic model consensus holds
true. With the loss of daytime heating and as the front slowly
slides off to the south and east, have gone dry for the early
morning hours on Sunday. Couldn`t completely remove PoPs out of the
forecast for the afternoon hours as a surface low riding along the
frontal boundary traverses across from west to east, once again
serving as a focus for renewed convection chances as surface high
pressure centered over the southern Great Lakes fights for control
over us. This fight, however, is very short lived as the high moves
off toward the East Coast and the next frontal boundary approaches
the Ohio Valley. This front is seemingly much faster with strong
Canadian high pressure pushing it southward from behind. What this
translates to for us is a continued unsettled period from Monday
through Tuesday night. By Wednesday, am hopeful that the boundary
will be south of the TN border, although the 12Z GFS tries to keep
the southern tier of counties wet through Wednesday night. Even if
the timing ends up being slightly off, the end result will be the
same for all of us: clearing skies, a much drier airmass, and cool
temperatures for this time of year.
Speaking of temperatures, we`ll see highs ranging from the lower to
upper 80s throughout the entire period with the warmest day looking
to be Monday and the coolest day on Thursday. Dewpoints will keep it
muggy from this weekend through mid-week before a noticeable
difference comes in by Wednesday-Thursday. Lows will be near normal
Saturday night through Tuesday night, dropping off to below normal
by Wednesday night. Looking at 850mb anomalous temps on NCEP`s
ensemble, the cool temps are depicted to prevail under the
aforementioned high for much of the end of next week.
&&
.AVIATION (00Z TAF Update)...
Issued at 716 PM EDT Thu Aug 8 2013
The TAF sites are staying dry at this point in the evening, however
there is a chance that a cluster of thunderstorms developing over south
central Illinois may impact SDF and LEX late this evening and
overnight. At this point, the bulk of the showers and storms should
stay across southern Indiana, although there is potential that the
southern end of the cluster could impact SDF/LEX. If this were to
happen it would likely be around the Midnight - 2 AM EDT time frame
at SDF, and around 2 - 4 AM EDT at LEX. For now, will stay more
optimistic at these locations, however it should be noted that if
the storms do impact the TAF sites, brief IFR visibilities and at
least MVFR ceilings will be likely. BWG also stands a shot at seeing
showers and storm overnight, however precipitation should hold off
until after 1 AM CDT, so will just be general with VCTS in the
forecast until we can get a better handle. Otherwise, ceilings
should stay VFR outside any storms. A better chance for MVFR may
occur again around dawn.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
Update.........MJ
Short Term.....JSD
Long Term......LG
Aviation.......BJS
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
821 PM EDT Thu Aug 8 2013
...Forecast Update...
Issued at 820 PM EDT Thu Aug 8 2013
Did a quick update to scale back precipitation chances for the next
few hours across much of Kentucky. Vorticity lobe continues to trek
eastward across Indiana this evening. Convection along the southern
edge of this boundary never really moved southward...but rather
eastward and looks to stay along and north of the I-64 corridor for
the next few hours. The best chances of rainfall in the near term
will be across our north edges of southern Indiana counties.
Secondary cluster of strong thunderstorms has rapidly intensified
across far eastern Arkansas and west Tennessee. This activity
continues to trek eastward and may affect the extreme southern
portions of our area toward the late evening hours. Additional
storms across east-central MO/IL are trying to develop. Latest
model data suggests this activity will further develop this evening
and then push into the region overnight. Will continue to go with
the higher PoPs for the later overnight period, but continue to
monitor the latest convective trends throughout the evening.
Update issued at 648 PM EDT Thu Aug 8 2013
Cluster of light to moderate rain showers continues to trek eastward
across portions of north-central Kentucky. This activity is
expected to continue for the next several hours, but should weaken
as it heads toward the I-75 corridor. More strongly forced
convection is rapidly developing on the southern side of a vorticity
max pushing eastward into Indiana. Storms are forming along a
differential heating and wind shift axis across southern Illinois.
This activity should continue to develop and track eastward along
the I-64 corridor this evening. Latest NAM and HRRR runs suggest
that this would impact north-central Kentucky during the overnight
period. Secondary area of storms is developing over southern MO and
northern AR, this activity will also head east, but may stay just
south of the forecast area late tonight.
With this update, have increased PoPs for the next few hours across
the central portions of the forecast area with the batch of
light-moderate rain moving through. Will continue to ramp up PoPs
tonight as the cluster of storms out to the west heads eastward into
the Ohio Valley.
.SHORT TERM (Now through Friday Night)...
Issued at 315 PM EDT Thu Aug 8 2013
An obstructed blocky flow continues over Canada late today with an
elongated west to east orientated 500mb low over Ontario and Quebec.
Farther south, a moderate westerly flow continues over the northern
Ohio Valley. Precipitable water values of near two inches or more
will continue through mid-day Friday, indicative of a tropical
airmass.
Quite a bit uncertainty still exists about where exactly convection
develops this evening. An circulation left over from last night`s
convection is now moving east northeast just to the south of St
Louis. This feature will move over southern Indiana late this
evening. This feature is supporting a cluster of thunderstorms now
moving east over western Kentucky. These storms are moving into an
unstable airmass southwest of Kentucky and should hold together
through this evening. Therefore, think storms late this afternoon
and early evening will become most numerous across west central
Kentucky, west of Interstate 65 and mostly to the south of
Interstate 64 across southern Indiana. A second area of convection
may drop south into south central Indiana late this evening. These
northern storms will form along a cold front slowly sagging south
across central Indiana. Will go likely for areas in Kentucky west of
Interstate 65 with scattered wording elsewhere.
Last night isolated storms over the Bluegrass produced very isolated
torrential rainfall amounts and flooding. This same scenario may play itself
out again tonight. Across south central Kentucky, localized heavy
rain and possible flooding are again possible in a few spots.
For Friday, a nearly stationary front will lie across southern
Indiana, nearly parallel to the Ohio River, any thunderstorm
development will highly depend on the location of any residual cloud
cover and outflow boundaries from overnight convection. Our best
moisture and convergence will lie over southern portions of our
Commonwealth. Slightly drier air will slowly filter in across
southern Indiana, limiting convective coverage there. Will continue
likely pops across southern Kentucky during the day Friday. Think
that any scattered storms will diminish across the north late
Friday, while hanging on near Tennessee.
Tonight will stay humid and muggy, with lows in the lower 70s, highs
Friday will reach the mid to upper 80s.
.LONG TERM (Saturday through Thursday)...
Issued at 309 PM EDT Thu Aug 8 2013
Quasi-stationary boundary laid out across the commonwealth will be
starting off this forecast period, allowing for the primary focus
for convection to be limited to southern portions of KY. Have
trended back PoPs for the northern half of the forecast area as such
since surface winds will have begun to back to the north by this
point, assuming the general deterministic model consensus holds
true. With the loss of daytime heating and as the front slowly
slides off to the south and east, have gone dry for the early
morning hours on Sunday. Couldn`t completely remove PoPs out of the
forecast for the afternoon hours as a surface low riding along the
frontal boundary traverses across from west to east, once again
serving as a focus for renewed convection chances as surface high
pressure centered over the southern Great Lakes fights for control
over us. This fight, however, is very short lived as the high moves
off toward the East Coast and the next frontal boundary approaches
the Ohio Valley. This front is seemingly much faster with strong
Canadian high pressure pushing it southward from behind. What this
translates to for us is a continued unsettled period from Monday
through Tuesday night. By Wednesday, am hopeful that the boundary
will be south of the TN border, although the 12Z GFS tries to keep
the southern tier of counties wet through Wednesday night. Even if
the timing ends up being slightly off, the end result will be the
same for all of us: clearing skies, a much drier airmass, and cool
temperatures for this time of year.
Speaking of temperatures, we`ll see highs ranging from the lower to
upper 80s throughout the entire period with the warmest day looking
to be Monday and the coolest day on Thursday. Dewpoints will keep it
muggy from this weekend through mid-week before a noticeable
difference comes in by Wednesday-Thursday. Lows will be near normal
Saturday night through Tuesday night, dropping off to below normal
by Wednesday night. Looking at 850mb anomalous temps on NCEP`s
ensemble, the cool temps are depicted to prevail under the
aforementioned high for much of the end of next week.
&&
.AVIATION (00Z TAF Update)...
Issued at 716 PM EDT Thu Aug 8 2013
The TAF sites are staying dry at this point in the evening, however
there is a chance that a cluster of thunderstorms developing over south
central Illinois may impact SDF and LEX late this evening and
overnight. At this point, the bulk of the showers and storms should
stay across southern Indiana, although there is potential that the
southern end of the cluster could impact SDF/LEX. If this were to
happen it would likely be around the Midnight - 2 AM EDT time frame
at SDF, and around 2 - 4 AM EDT at LEX. For now, will stay more
optimistic at these locations, however it should be noted that if
the storms do impact the TAF sites, brief IFR visibilities and at
least MVFR ceilings will be likely. BWG also stands a shot at seeing
showers and storm overnight, however precipitation should hold off
until after 1 AM CDT, so will just be general with VCTS in the
forecast until we can get a better handle. Otherwise, ceilings
should stay VFR outside any storms. A better chance for MVFR may
occur again around dawn.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
Update.........MJ
Short Term.....JSD
Long Term......LG
Aviation.......BJS
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
719 PM EDT Thu Aug 8 2013
...Updated Aviation Discussion...
...Forecast Update...
Issued at 648 PM EDT Thu Aug 8 2013
Cluster of light to moderate rain showers continues to trek eastward
across portions of north-central Kentucky. This activity is
expected to continue for the next several hours, but should weaken
as it heads toward the I-75 corridor. More strongly forced
convection is rapidly developing on the southern side of a vorticity
max pushing eastward into Indiana. Storms are forming along a
differential heating and wind shift axis across southern Illinois.
This activity should continue to develop and track eastward along
the I-64 corridor this evening. Latest NAM and HRRR runs suggest
that this would impact north-central Kentucky during the overnight
period. Secondary area of storms is developing over southern MO and
northern AR, this activity will also head east, but may stay just
south of the forecast area late tonight.
With this update, have increased PoPs for the next few hours across
the central portions of the forecast area with the batch of
light-moderate rain moving through. Will continue to ramp up PoPs
tonight as the cluster of storms out to the west heads eastward into
the Ohio Valley.
.SHORT TERM (Now through Friday Night)...
Issued at 315 PM EDT Thu Aug 8 2013
An obstructed blocky flow continues over Canada late today with an
elongated west to east orientated 500mb low over Ontario and Quebec.
Farther south, a moderate westerly flow continues over the northern
Ohio Valley. Precipitable water values of near two inches or more
will continue through mid-day Friday, indicative of a tropical
airmass.
Quite a bit uncertainty still exists about where exactly convection
develops this evening. An circulation left over from last night`s
convection is now moving east northeast just to the south of St
Louis. This feature will move over southern Indiana late this
evening. This feature is supporting a cluster of thunderstorms now
moving east over western Kentucky. These storms are moving into an
unstable airmass southwest of Kentucky and should hold together
through this evening. Therefore, think storms late this afternoon
and early evening will become most numerous across west central
Kentucky, west of Interstate 65 and mostly to the south of
Interstate 64 across southern Indiana. A second area of convection
may drop south into south central Indiana late this evening. These
northern storms will form along a cold front slowly sagging south
across central Indiana. Will go likely for areas in Kentucky west of
Interstate 65 with scattered wording elsewhere.
Last night isolated storms over the Bluegrass produced very isolated
torrential rainfall amounts and flooding. This same scenario may play itself
out again tonight. Across south central Kentucky, localized heavy
rain and possible flooding are again possible in a few spots.
For Friday, a nearly stationary front will lie across southern
Indiana, nearly parallel to the Ohio River, any thunderstorm
development will highly depend on the location of any residual cloud
cover and outflow boundaries from overnight convection. Our best
moisture and convergence will lie over southern portions of our
Commonwealth. Slightly drier air will slowly filter in across
southern Indiana, limiting convective coverage there. Will continue
likely pops across southern Kentucky during the day Friday. Think
that any scattered storms will diminish across the north late
Friday, while hanging on near Tennessee.
Tonight will stay humid and muggy, with lows in the lower 70s, highs
Friday will reach the mid to upper 80s.
.LONG TERM (Saturday through Thursday)...
Issued at 309 PM EDT Thu Aug 8 2013
Quasi-stationary boundary laid out across the commonwealth will be
starting off this forecast period, allowing for the primary focus
for convection to be limited to southern portions of KY. Have
trended back PoPs for the northern half of the forecast area as such
since surface winds will have begun to back to the north by this
point, assuming the general deterministic model consensus holds
true. With the loss of daytime heating and as the front slowly
slides off to the south and east, have gone dry for the early
morning hours on Sunday. Couldn`t completely remove PoPs out of the
forecast for the afternoon hours as a surface low riding along the
frontal boundary traverses across from west to east, once again
serving as a focus for renewed convection chances as surface high
pressure centered over the southern Great Lakes fights for control
over us. This fight, however, is very short lived as the high moves
off toward the East Coast and the next frontal boundary approaches
the Ohio Valley. This front is seemingly much faster with strong
Canadian high pressure pushing it southward from behind. What this
translates to for us is a continued unsettled period from Monday
through Tuesday night. By Wednesday, am hopeful that the boundary
will be south of the TN border, although the 12Z GFS tries to keep
the southern tier of counties wet through Wednesday night. Even if
the timing ends up being slightly off, the end result will be the
same for all of us: clearing skies, a much drier airmass, and cool
temperatures for this time of year.
Speaking of temperatures, we`ll see highs ranging from the lower to
upper 80s throughout the entire period with the warmest day looking
to be Monday and the coolest day on Thursday. Dewpoints will keep it
muggy from this weekend through mid-week before a noticeable
difference comes in by Wednesday-Thursday. Lows will be near normal
Saturday night through Tuesday night, dropping off to below normal
by Wednesday night. Looking at 850mb anomalous temps on NCEP`s
ensemble, the cool temps are depicted to prevail under the
aforementioned high for much of the end of next week.
&&
.AVIATION (00Z TAF Update)...
Issued at 716 PM EDT Thu Aug 8 2013
The TAF sites are staying dry at this point in the evening, however
there is a chance that a cluster of thunderstorms developing over south
central Illinois may impact SDF and LEX late this evening and
overnight. At this point, the bulk of the showers and storms should
stay across southern Indiana, although there is potential that the
southern end of the cluster could impact SDF/LEX. If this were to
happen it would likely be around the Midnight - 2 AM EDT time frame
at SDF, and around 2 - 4 AM EDT at LEX. For now, will stay more
optimistic at these locations, however it should be noted that if
the storms do impact the TAF sites, brief IFR visibilities and at
least MVFR ceilings will be likely. BWG also stands a shot at seeing
showers and storm overnight, however precipitation should hold off
until after 1 AM CDT, so will just be general with VCTS in the
forecast until we can get a better handle. Otherwise, ceilings
should stay VFR outside any storms. A better chance for MVFR may
occur again around dawn.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
Update.........MJ
Short Term.....JSD
Long Term......LG
Aviation.......BJS
AREA FORECAST DISCUSSION
NWS JACKSON KY
152 PM EDT WED AUG 7 2013
.UPDATE...
ISSUED AT 151 PM EDT WED AUG 7 2013
UPDATED TO NDFD FOR LATEST OBSERVATIONAL TRENDS. BASED ON CURRENT
RADAR TRENDS HAVE TAPERED THE NUMEROUS SHOWERS IN THE EAST TO
SCATTERED A LITTLE QUICKER THAN PREVIOUS FORECAST. CONVECTIVE
COVERAGE LOOKS TO REMAIN SCATTERED ACROSS THE ENTIRE AREA FOR THE
REMAINDER OF THE AFTERNOON WITH MORE SHOWERS THAN THUNDERSTORMS.
UPDATE ISSUED AT 1147 AM EDT WED AUG 7 2013
NDFD AND ZFP HAVE BEEN UPDATED. WHILE THE EARLY MORNING RUNS OF THE
HRRR DID NOT DO A VERY GOOD JOB HANDLING THE CONVECTION THIS
MORNING...THE 12 NAM SEEMS TO HAVE A BETTER HANDLE ON THINGS. BASED
ON CURRENT TRENDS THE NUMEROUS SHOWERS IN THE SOUTHEAST WILL CONTINUE
FOR THE NEXT FEW HOURS...WITH SCATTERED THUNDERSTORMS POSSIBLE
ANYWHERE IN THE FORECAST AREA AS WE MOVE INTO THE AFTERNOON. HAVE
ADJUSTED AFTERNOON CONVECTIVE COVERAGE TO NUMEROUS IN THE SOUTHEAST
AND SCATTERED ELSEWHERE. AFTERNOON TEMPERATURES AND EXTENT OF CONVECTIVE
DEVELOPMENT WILL BE ALMOST ENTIRELY DEPENDENT ON SKY COVER. STILL
EXPECT ENOUGH BREAKS TO ALLOW TEMPERATURES TO RISE INTO THE LOWER
80S IN MOST AREAS.
UPDATE ISSUED AT 956 AM EDT WED AUG 7 2013
NDFD AND ASSOCIATED PRODUCTS...INCLUDING ZFP HAVE BEEN UPDATED. THE
NEAR TERM MODELS ARE NOT HANDLING THIS MORNINGS CONVECTION VERY
WELL...AND AS SUCH THIS THROWS DOUBT INTO THE NEAR TERM GUIDANCE FOR
THE REST OF THE DAY INTO TONIGHT. THE 11Z HRRR SHOWED THE DEVELOPMENT
OF THE CONVECTION EARLY THIS MORNING BUT QUICKLY HAD IT DIE AWAY
BEFORE BRINGING AN ORGANIZED BAND OF CONVECTION ACROSS THE AREA FROM
LATE MORNING INTO EARLY AFTERNOON WITH ANOTHER ROUND OF ORGANIZED CONVECTION
FROM LATE AFTERNOON INTO THE EVENING. THE 12Z HRRR IS JUST COMING
IN...AND STILL NOT HANDLING THIS MORNINGS CONVECTION VERY WELL...BUT
IS LEANING TOWARDS MORE DISORGANIZATION IN THE CONVECTION FOR THIS
AFTERNOON.
THERE WILL BE CONSIDERABLE DEBRIS CLOUDINESS ACROSS THE AREA
TODAY...BUT EXPECT SOME BREAKS IN THE CLOUDS IN THE WAKE OF THE
SHOWERS AND THUNDERSTORMS THAT OCCUR THIS MORNING. THIS WOULD ALLOW
ADDITIONAL DESTABILIZATION WITH MORE AFTERNOON HEATING. WHERE BREAKS
HAVE OCCURRED IN CENTRAL KY TEMPERATURES HAVE JUMPED INTO THE UPPER
70S AND AS SUCH WILL INCREASE AFTERNOON MAXIMUM TEMPERATURES SEVERAL
DEGREES. WITH NUMEROUS SHOWERS ALREADY OCCURRING ACROSS THE AREA HAVE
INCREASED RAIN CHANCES FOR THIS MORNING IN ALL BUT THE FAR
NORTH...YIELDING NUMEROUS SHOWERS AND THUNDERSTORMS IN THE FORECAST
FOR TODAY IN MOST AREAS...RATHER THAN JUST FOR THIS AFTERNOON.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 356 AM EDT WED AUG 7 2013
THE ENTIRE FORECAST WILL BE PROGGED BY SUBTLE SHORTWAVES MOVING
EASTWARD FROM THE ROCKIES AND GREAT PLAINS...AND IMPACTING KY OR
SURROUNDING AREAS. FOR THE SHORT TERM...THE FOCUS WILL BE ON A SHORT
WAVE THAT MODEL CONSENSUS HAS REACHING WESTERN KY BY 18Z TODAY...AND
EASTERN KY IN THE EVENING AROUND 0Z. ANOTHER LARGER SHORTWAVE WILL
THEN APPROACH WESTERN KY AND MUCH OF TN THE FOLLOWING AFTERNOON ON
THURSDAY. BOTH OF THESE WAVES WILL TRANSLATE TO SURFACE INSTABILITY
AND THE EXPECTATION OF CONVECTIVE DEVELOPMENT.
STARTING WITH TODAY...A WARM FRONT THAT MOVED THROUGH LAST NIGHT HAS
ALLOWED FOR STRONG WAA AND A VAST INCREASE IN THE HUMIDITY VALUES.
WHILE EXPECTED CLOUD COVER TODAY WILL KEEP TEMPERATURES FROM RISING
TO THEIR FULL POTENTIAL...DEW POINTS ON THE OTHER HAND WILL RISE TO
THE LOW 70S...ALLOWING FOR HIGH HUMIDITY AND APPARENT TEMPERATURES
IN THE MID AND UPPER 80S IN SOME LOCATIONS. THE SHORTWAVE
APPROACHING FROM THE WEST WILL TRANSLATE TO A SURFACE LOW PRESSURE
SYSTEM TO THE NORTH OVER THE UPPER GREAT LAKES. AS THIS SHORTWAVE
AND ASSOCIATED LOW PRESSURE SYSTEM CONTINUE ON THEIR TREK
NORTHEAST...IT WILL PULL A LARGE COLD FRONT SEWARD ACROSS
MI/IN/IL/AND MO DURING THE AFTERNOON...NEARING THE OHIO VALLEY
WEDNESDAY NIGHT. WITH THE VERY MOIST AND UNSTABLE ENVIRONMENT
ALREADY AT PLAY DURING THE DAY TODAY...THE ISENTROPIC LIFT AHEAD OF
THE APPROACHING FRONT WILL BE ENOUGH TO KICK START CONVECTION ACROSS
THE AREA. WHILE MODELS ARE STILL SOMEWHAT LACKLUSTER ON THEIR
SOLUTION AGREEMENT...WILL GO WITH THE CONSENSUS THAT BEST PRECIP
POTENTIAL WILL BE IN THE FAR EASTERN PORTION OF THE CWA BETWEEN 15
AND 0Z TODAY. WITH GOOD DIRECTIONAL AND SPEED SHEAR...AS WELL AS
MARGINAL CAPE VALUES...COULD SEE STORMS DEVELOP ACROSS THE ENTIRE
CWA. WITH MOIST LOW LEVELS AND DRY AIR FILTERING IN THE MID AND UPPER
LEVELS...COULD SEE SOME POTENTIAL FOR STRONG WINDS AND SMALL HAIL
DEVELOPMENT IN ADDITION TO SOME HEAVY DOWNPOURS.
BEST CONVECTIVE ACTIVITY WILL DIE DOWN OVERNIGHT WITH LOSS OF
DAYTIME HEATING...BUT AS COLD FRONT JUST TO OUR NORTH BECOMES NEARLY
STATIONARY...THERE WILL BE ENOUGH INSTABILITY AND LIFT NEARBY TO
PREVENT DROPPING POPS BELOW CHANCES. THIS WILL BE REINFORCED BY THE
FACT THAT CLOUD COVER AND CONTINUED WARM AIR FILTERING IN FROM THE
SOUTH WILL PREVENT LOWS FROM DROPPING BELOW 70 IN MANY LOCATIONS.
THIS WILL RESULT IN A VERY SOUPY NIGHT WITH HUMIDITY VALUES RANGING
FROM 90 TO 100 PERCENT ACROSS MUCH OF THE REGION. ANY LITTLE THING
COULD BE ENOUGH TO INITIATE SOME SORT OF PRECIP IN SUCH AN
ENVIRONMENT AS A RESULT.
BY 12Z THURSDAY...THE NEXT SHORTWAVE TO IMPACT THE AREA WILL FIND
ITSELF OVER MISSOURI AND NORTHERN ARKANSAS. AT THE SURFACE...THIS
WILL BEGIN INTERACTING WITH THE STATIONARY SURFACE COLD FRONT AND
THE DAYTIME INSTABILITY...BRINGING AN INCREASE OF CONVECTION ACROSS
WESTERN KY IN THE MORNING...AND THEN ACROSS THE ENTIRE FRONTAL
BOUNDARY BY AFTERNOON...WITH PRECIP CHANCES EXPECTED TO IMPACT FROM
AS FAR WEST AS COLORADO...THEN POINTS EASTWARD...AND ACROSS THE
ENTIRETY OF THE EASTERN SEABOARD. ONCE AGAIN...MODEL CONSENSUS IS
PEGGING THE FAR EASTERN PORTIONS OF THE STATE FOR THE BEST QPF AND
PRECIP POTENTIAL...THOUGH IN SUCH AN ENVIRONMENT SCT TO WIDESPREAD
STORM DEVELOPMENT CAN BE EXPECTED JUST ABOUT ANYWHERE ACROSS THE
REGION. CAPE VALUES THIS DAY WILL BE MUCH MORE SUBSTANTIAL IN THE
EAST CENTRAL...WITH MOIST LOW LEVELS AND DRY AIR FILTERING IN ALOFT
DURING THE AFTERNOON HOURS. THE LATEST ECMWF IS ALSO SHOWING THAT
WHILE LAPSE RATES WILL STILL NOT BE THAT IMPRESSIVE...THERE WILL BE
A GOOD AREA OF QVECTOR CONVERGENCE THAT MOVES ACROSS THE STATE
THURSDAY AFTERNOON/EVENING. ALL THINGS BEING FACTORED IN...LATEST
NAM SOUNDINGS SUPPORT THE IDEA THAT WITH LITTLE IN THE WAY OF LAPSE
RATES AND PWAT VALUES NEARING 2 INCHES IN SOME PLACES...WILL PROBABLY
EXPECT MORE OF A HEAVY RAIN THREAT WITH THESE STORMS COMPARED TO
TODAY. SOME ISOLATED STRONGER STORMS CAN NOT BE RULED OUT HOWEVER.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 356 AM EDT WED AUG 7 2013
THE MODELS CONTINUE TO BE IN PRETTY GOOD AGREEMENT WITH THE OVERALL
PATTERN ALOFT FOR THE EXTENDED. LIKE LAST NIGHT...THE MAIN
DIFFERENCES REVOLVE AROUND SHORTWAVES AND MESOSCALE FEATURES THAT
ARE MORE DIFFICULT TO RESOLVE THIS FAR OUT. THE GENERAL PATTERN
STARTS WITH A DOMINANT TROUGH OVER SOUTH CENTRAL CANADA NORTH OF
FLAT RIDGING COVERING THE SOUTHERN TIER OF THE STATES. BETWEEN
THESE...RELATIVELY FAST FLOW WILL BRING ENERGY FROM THE WEST COAST
TO THE EAST PASSING THROUGH THE OHIO VALLEY. WHILE THE CORE OF THE
NORTHERN TROUGH MOVES EAST BY EARLY SATURDAY THE TROUGH ITSELF WILL
REFORM OVER THE WEEKEND AND ACTUALLY BUILD SOUTH TO ENCOMPASS THE
GREAT LAKES OHIO VALLEY BY 00Z TUESDAY. OVER OUR AREA THIS EVOLUTION
WILL BUCKLE THE INITIALLY ZONAL PATTERN INTO ONE OF NORTHWEST FLOW.
THROUGH IT ALL...KENTUCKY WILL HAVE TO DEAL WITH PASSING WAVES OF
MID LEVEL ENERGY ALONG WITH ANY THAT MAY BE CONVECTIVELY DRIVEN.
THIS SHOULD MEAN AN LARGELY UNSETTLED PERIOD OF WEATHER. DUE
TO THE GENERAL MODEL AGREEMENT...HAVE FAVORED A MODEL BLEND WITH A
BIT OF A LEAN TOWARD THE 00Z ECMWF.
SENSIBLE WEATHER WILL FEATURE AN EXTENDED PERIOD OF POTENTIALLY
EXCESSIVE RAINS AS A FRONTAL BOUNDARY AND HIGHER THAN NORMAL PW AIR
WILL REMAIN IN IN PLACE THROUGH THE WEEKEND. COMBINED WITH DAYTIME
INSTABILITY...AND SOME UPPER LEVEL SUPPORT...EACH DAY COULD TURN OUT
TO BE A WASHOUT WITH HEAVY RAIN FROM A COMPLEX OF SHOWERS AND
THUNDERSTORMS. HOWEVER...SIMILAR TO TODAY...SOME OF THESE PARAMETERS
MAY NOT COME TOGETHER AND A GOOD PORTION OF THE AREA COULD BE DRY
DESPITE THE SET UP. AS SUCH...THE FORECAST WILL CONSIST OF
HIGHER POP CHANCES DURING THE LATE AFTERNOON AND EARLY EVENING HOURS
WITH A DIMINISHMENT AT NIGHT THROUGH SUNDAY. OF COURSE...ANY MCS
ACTIVITY COULD EASILY EXTEND INTO THE NIGHT SO CANNOT GO DRY FOR
THESE TIMES EITHER. UNFORTUNATELY...WITH THE POTENTIAL FOR MCS
DEVELOPMENT THROUGH THE BULK OF THE EXTENDED...CONFIDENCE IS LOWER
THAN NORMAL FOR FORECAST SPECIFICS ASIDE FROM THE ACKNOWLEDGMENT OF
THE BUILT UP POSSIBILITIES. THEREFORE...THE FORECAST WILL CONSIST OF
RATHER HIGH POPS THROUGH THE WEEKEND...WITH LESS OF A THREAT ON
MONDAY AND TUESDAY IF THE NEW ECMWF IS RIGHT AND THE FRONT DROPS
SOUTH. ALONG WITH THE HIGH POPS WILL GO COOLER THAN NORMAL TEMPS...
THOUGH THE HIGH DEWPOINTS WILL MAKE IT FEEL SEVERAL DEGREES WARMER
THAN ACTUAL AIR TEMPERATURE. BASED ON THE 00Z ECMWF...HIGH PRESSURE
MAY BE ABLE TO PUSH IN AND SHOVE THE MORE HUMID AIR SOUTH FOR A GOOD
PORTION OF THE UPCOMING WEEK. UNTIL THEN...THOUGH...WE WILL BE AWASH
IN A MUGGY AIR MASS COMPLETE WITH MOST OF THE INGREDIENTS NEEDED FOR
HEAVY RAINS.
THE CR GRID LOAD CAME IN PRETTY GOOD FOR THIS CONVECTIVELY UNSETTLED
SITUATION. DID TWEAK POPS TO ADD MORE OF A DIURNAL CYCLE AND ALSO
TOWARD THE LATEST SPECIFICS FROM THE ECMWF. ONLY MADE MINOR TERRAIN
BASED ADJUSTMENTS FOR TEMPS THROUGHOUT THE EXTENDED PERIOD GIVEN THE
HIGH MOISTURE CONTENT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 151 PM EDT WED AUG 7 2013
SCATTERED SHOWERS AND A FEW THUNDERSTORMS WILL CONTINUE TO AFFECT THE
ENTIRE FORECAST AREA FOR THE REMAINDER OF THE AFTERNOON. WITH THE
WIDELY SCATTERED NATURE OF THE CONVECTION WILL GO WITH VCTS IN THE
TAFS FOR THE REMAINDER OF THE AFTERNOON. THE GENERAL TREND WILL BE
FOR CEILINGS TO INCREASE THROUGH THE AFTERNOON INTO THE EVENING WITH
MVFR TO VFR CEILINGS THIS AFTERNOON GIVING WAY TO ALL VFR CEILINGS THIS
EVENING. CONDITIONS WILL DETERIORATE LATE TONIGHT AND INTO THE DAY ON
THURSDAY AS MORE WIDESPREAD SHOWERS AND THUNDERSTORMS MOVE INTO THE
AREA IN ADVANCE OF AN APPROACHING COLD FRONT. EXPECT WIDESPREAD MVFR
CONDITIONS BY DAYBREAK THURSDAY. CONDITIONS WILL THEN LIKELY IMPROVE
LATE IN THE DAY ON THURSDAY.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SBH
SHORT TERM...JMW
LONG TERM...GREIF
AVIATION...SBH
AREA FORECAST DISCUSSION
NWS JACKSON KY
1147 AM EDT WED AUG 7 2013
.UPDATE...
ISSUED AT 1147 AM EDT WED AUG 7 2013
NDFD AND ZFP HAVE BEEN UPDATED. WHILE THE EARLY MORNING RUNS OF THE
HRRR DID NOT DO A VERY GOOD JOB HANDLING THE CONVECTION THIS
MORNING...THE 12 NAM SEEMS TO HAVE A BETTER HANDLE ON THINGS. BASED
ON CURRENT TRENDS THE NUMEROUS SHOWERS IN THE SOUTHEAST WILL CONTINUE
FOR THE NEXT FEW HOURS...WITH SCATTERED THUNDERSTORMS POSSIBLE
ANYWHERE IN THE FORECAST AREA AS WE MOVE INTO THE AFTERNOON. HAVE
ADJUSTED AFTERNOON CONVECTIVE COVERAGE TO NUMEROUS IN THE SOUTHEAST
AND SCATTERED ELSEWHERE. AFTERNOON TEMPERATURES AND EXTENT OF CONVECTIVE
DEVELOPMENT WILL BE ALMOST ENTIRELY DEPENDENT ON SKY COVER. STILL
EXPECT ENOUGH BREAKS TO ALLOW TEMPERATURES TO RISE INTO THE LOWER
80S IN MOST AREAS.
UPDATE ISSUED AT 956 AM EDT WED AUG 7 2013
NDFD AND ASSOCIATED PRODUCTS...INCLUDING ZFP HAVE BEEN UPDATED. THE
NEAR TERM MODELS ARE NOT HANDLING THIS MORNINGS CONVECTION VERY
WELL...AND AS SUCH THIS THROWS DOUBT INTO THE NEAR TERM GUIDANCE FOR
THE REST OF THE DAY INTO TONIGHT. THE 11Z HRRR SHOWED THE DEVELOPMENT
OF THE CONVECTION EARLY THIS MORNING BUT QUICKLY HAD IT DIE AWAY
BEFORE BRINGING AN ORGANIZED BAND OF CONVECTION ACROSS THE AREA FROM
LATE MORNING INTO EARLY AFTERNOON WITH ANOTHER ROUND OF ORGANIZED CONVECTION
FROM LATE AFTERNOON INTO THE EVENING. THE 12Z HRRR IS JUST COMING
IN...AND STILL NOT HANDLING THIS MORNINGS CONVECTION VERY WELL...BUT
IS LEANING TOWARDS MORE DISORGANIZATION IN THE CONVECTION FOR THIS
AFTERNOON.
THERE WILL BE CONSIDERABLE DEBRIS CLOUDINESS ACROSS THE AREA
TODAY...BUT EXPECT SOME BREAKS IN THE CLOUDS IN THE WAKE OF THE
SHOWERS AND THUNDERSTORMS THAT OCCUR THIS MORNING. THIS WOULD ALLOW
ADDITIONAL DESTABILIZATION WITH MORE AFTERNOON HEATING. WHERE BREAKS
HAVE OCCURRED IN CENTRAL KY TEMPERATURES HAVE JUMPED INTO THE UPPER
70S AND AS SUCH WILL INCREASE AFTERNOON MAXIMUM TEMPERATURES SEVERAL
DEGREES. WITH NUMEROUS SHOWERS ALREADY OCCURRING ACROSS THE AREA HAVE
INCREASED RAIN CHANCES FOR THIS MORNING IN ALL BUT THE FAR
NORTH...YIELDING NUMEROUS SHOWERS AND THUNDERSTORMS IN THE FORECAST
FOR TODAY IN MOST AREAS...RATHER THAN JUST FOR THIS AFTERNOON.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 356 AM EDT WED AUG 7 2013
THE ENTIRE FORECAST WILL BE PROGGED BY SUBTLE SHORTWAVES MOVING
EASTWARD FROM THE ROCKIES AND GREAT PLAINS...AND IMPACTING KY OR
SURROUNDING AREAS. FOR THE SHORT TERM...THE FOCUS WILL BE ON A SHORT
WAVE THAT MODEL CONSENSUS HAS REACHING WESTERN KY BY 18Z TODAY...AND
EASTERN KY IN THE EVENING AROUND 0Z. ANOTHER LARGER SHORTWAVE WILL
THEN APPROACH WESTERN KY AND MUCH OF TN THE FOLLOWING AFTERNOON ON
THURSDAY. BOTH OF THESE WAVES WILL TRANSLATE TO SURFACE INSTABILITY
AND THE EXPECTATION OF CONVECTIVE DEVELOPMENT.
STARTING WITH TODAY...A WARM FRONT THAT MOVED THROUGH LAST NIGHT HAS
ALLOWED FOR STRONG WAA AND A VAST INCREASE IN THE HUMIDITY VALUES.
WHILE EXPECTED CLOUD COVER TODAY WILL KEEP TEMPERATURES FROM RISING
TO THEIR FULL POTENTIAL...DEW POINTS ON THE OTHER HAND WILL RISE TO
THE LOW 70S...ALLOWING FOR HIGH HUMIDITY AND APPARENT TEMPERATURES
IN THE MID AND UPPER 80S IN SOME LOCATIONS. THE SHORTWAVE
APPROACHING FROM THE WEST WILL TRANSLATE TO A SURFACE LOW PRESSURE
SYSTEM TO THE NORTH OVER THE UPPER GREAT LAKES. AS THIS SHORTWAVE
AND ASSOCIATED LOW PRESSURE SYSTEM CONTINUE ON THEIR TREK
NORTHEAST...IT WILL PULL A LARGE COLD FRONT SEWARD ACROSS
MI/IN/IL/AND MO DURING THE AFTERNOON...NEARING THE OHIO VALLEY
WEDNESDAY NIGHT. WITH THE VERY MOIST AND UNSTABLE ENVIRONMENT
ALREADY AT PLAY DURING THE DAY TODAY...THE ISENTROPIC LIFT AHEAD OF
THE APPROACHING FRONT WILL BE ENOUGH TO KICK START CONVECTION ACROSS
THE AREA. WHILE MODELS ARE STILL SOMEWHAT LACKLUSTER ON THEIR
SOLUTION AGREEMENT...WILL GO WITH THE CONSENSUS THAT BEST PRECIP
POTENTIAL WILL BE IN THE FAR EASTERN PORTION OF THE CWA BETWEEN 15
AND 0Z TODAY. WITH GOOD DIRECTIONAL AND SPEED SHEAR...AS WELL AS
MARGINAL CAPE VALUES...COULD SEE STORMS DEVELOP ACROSS THE ENTIRE
CWA. WITH MOIST LOW LEVELS AND DRY AIR FILTERING IN THE MID AND UPPER
LEVELS...COULD SEE SOME POTENTIAL FOR STRONG WINDS AND SMALL HAIL
DEVELOPMENT IN ADDITION TO SOME HEAVY DOWNPOURS.
BEST CONVECTIVE ACTIVITY WILL DIE DOWN OVERNIGHT WITH LOSS OF
DAYTIME HEATING...BUT AS COLD FRONT JUST TO OUR NORTH BECOMES NEARLY
STATIONARY...THERE WILL BE ENOUGH INSTABILITY AND LIFT NEARBY TO
PREVENT DROPPING POPS BELOW CHANCES. THIS WILL BE REINFORCED BY THE
FACT THAT CLOUD COVER AND CONTINUED WARM AIR FILTERING IN FROM THE
SOUTH WILL PREVENT LOWS FROM DROPPING BELOW 70 IN MANY LOCATIONS.
THIS WILL RESULT IN A VERY SOUPY NIGHT WITH HUMIDITY VALUES RANGING
FROM 90 TO 100 PERCENT ACROSS MUCH OF THE REGION. ANY LITTLE THING
COULD BE ENOUGH TO INITIATE SOME SORT OF PRECIP IN SUCH AN
ENVIRONMENT AS A RESULT.
BY 12Z THURSDAY...THE NEXT SHORTWAVE TO IMPACT THE AREA WILL FIND
ITSELF OVER MISSOURI AND NORTHERN ARKANSAS. AT THE SURFACE...THIS
WILL BEGIN INTERACTING WITH THE STATIONARY SURFACE COLD FRONT AND
THE DAYTIME INSTABILITY...BRINGING AN INCREASE OF CONVECTION ACROSS
WESTERN KY IN THE MORNING...AND THEN ACROSS THE ENTIRE FRONTAL
BOUNDARY BY AFTERNOON...WITH PRECIP CHANCES EXPECTED TO IMPACT FROM
AS FAR WEST AS COLORADO...THEN POINTS EASTWARD...AND ACROSS THE
ENTIRETY OF THE EASTERN SEABOARD. ONCE AGAIN...MODEL CONSENSUS IS
PEGGING THE FAR EASTERN PORTIONS OF THE STATE FOR THE BEST QPF AND
PRECIP POTENTIAL...THOUGH IN SUCH AN ENVIRONMENT SCT TO WIDESPREAD
STORM DEVELOPMENT CAN BE EXPECTED JUST ABOUT ANYWHERE ACROSS THE
REGION. CAPE VALUES THIS DAY WILL BE MUCH MORE SUBSTANTIAL IN THE
EAST CENTRAL...WITH MOIST LOW LEVELS AND DRY AIR FILTERING IN ALOFT
DURING THE AFTERNOON HOURS. THE LATEST ECMWF IS ALSO SHOWING THAT
WHILE LAPSE RATES WILL STILL NOT BE THAT IMPRESSIVE...THERE WILL BE
A GOOD AREA OF QVECTOR CONVERGENCE THAT MOVES ACROSS THE STATE
THURSDAY AFTERNOON/EVENING. ALL THINGS BEING FACTORED IN...LATEST
NAM SOUNDINGS SUPPORT THE IDEA THAT WITH LITTLE IN THE WAY OF LAPSE
RATES AND PWAT VALUES NEARING 2 INCHES IN SOME PLACES...WILL PROBABLY
EXPECT MORE OF A HEAVY RAIN THREAT WITH THESE STORMS COMPARED TO
TODAY. SOME ISOLATED STRONGER STORMS CAN NOT BE RULED OUT HOWEVER.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 356 AM EDT WED AUG 7 2013
THE MODELS CONTINUE TO BE IN PRETTY GOOD AGREEMENT WITH THE OVERALL
PATTERN ALOFT FOR THE EXTENDED. LIKE LAST NIGHT...THE MAIN
DIFFERENCES REVOLVE AROUND SHORTWAVES AND MESOSCALE FEATURES THAT
ARE MORE DIFFICULT TO RESOLVE THIS FAR OUT. THE GENERAL PATTERN
STARTS WITH A DOMINANT TROUGH OVER SOUTH CENTRAL CANADA NORTH OF
FLAT RIDGING COVERING THE SOUTHERN TIER OF THE STATES. BETWEEN
THESE...RELATIVELY FAST FLOW WILL BRING ENERGY FROM THE WEST COAST
TO THE EAST PASSING THROUGH THE OHIO VALLEY. WHILE THE CORE OF THE
NORTHERN TROUGH MOVES EAST BY EARLY SATURDAY THE TROUGH ITSELF WILL
REFORM OVER THE WEEKEND AND ACTUALLY BUILD SOUTH TO ENCOMPASS THE
GREAT LAKES OHIO VALLEY BY 00Z TUESDAY. OVER OUR AREA THIS EVOLUTION
WILL BUCKLE THE INITIALLY ZONAL PATTERN INTO ONE OF NORTHWEST FLOW.
THROUGH IT ALL...KENTUCKY WILL HAVE TO DEAL WITH PASSING WAVES OF
MID LEVEL ENERGY ALONG WITH ANY THAT MAY BE CONVECTIVELY DRIVEN.
THIS SHOULD MEAN AN LARGELY UNSETTLED PERIOD OF WEATHER. DUE
TO THE GENERAL MODEL AGREEMENT...HAVE FAVORED A MODEL BLEND WITH A
BIT OF A LEAN TOWARD THE 00Z ECMWF.
SENSIBLE WEATHER WILL FEATURE AN EXTENDED PERIOD OF POTENTIALLY
EXCESSIVE RAINS AS A FRONTAL BOUNDARY AND HIGHER THAN NORMAL PW AIR
WILL REMAIN IN IN PLACE THROUGH THE WEEKEND. COMBINED WITH DAYTIME
INSTABILITY...AND SOME UPPER LEVEL SUPPORT...EACH DAY COULD TURN OUT
TO BE A WASHOUT WITH HEAVY RAIN FROM A COMPLEX OF SHOWERS AND
THUNDERSTORMS. HOWEVER...SIMILAR TO TODAY...SOME OF THESE PARAMETERS
MAY NOT COME TOGETHER AND A GOOD PORTION OF THE AREA COULD BE DRY
DESPITE THE SET UP. AS SUCH...THE FORECAST WILL CONSIST OF
HIGHER POP CHANCES DURING THE LATE AFTERNOON AND EARLY EVENING HOURS
WITH A DIMINISHMENT AT NIGHT THROUGH SUNDAY. OF COURSE...ANY MCS
ACTIVITY COULD EASILY EXTEND INTO THE NIGHT SO CANNOT GO DRY FOR
THESE TIMES EITHER. UNFORTUNATELY...WITH THE POTENTIAL FOR MCS
DEVELOPMENT THROUGH THE BULK OF THE EXTENDED...CONFIDENCE IS LOWER
THAN NORMAL FOR FORECAST SPECIFICS ASIDE FROM THE ACKNOWLEDGMENT OF
THE BUILT UP POSSIBILITIES. THEREFORE...THE FORECAST WILL CONSIST OF
RATHER HIGH POPS THROUGH THE WEEKEND...WITH LESS OF A THREAT ON
MONDAY AND TUESDAY IF THE NEW ECMWF IS RIGHT AND THE FRONT DROPS
SOUTH. ALONG WITH THE HIGH POPS WILL GO COOLER THAN NORMAL TEMPS...
THOUGH THE HIGH DEWPOINTS WILL MAKE IT FEEL SEVERAL DEGREES WARMER
THAN ACTUAL AIR TEMPERATURE. BASED ON THE 00Z ECMWF...HIGH PRESSURE
MAY BE ABLE TO PUSH IN AND SHOVE THE MORE HUMID AIR SOUTH FOR A GOOD
PORTION OF THE UPCOMING WEEK. UNTIL THEN...THOUGH...WE WILL BE AWASH
IN A MUGGY AIR MASS COMPLETE WITH MOST OF THE INGREDIENTS NEEDED FOR
HEAVY RAINS.
THE CR GRID LOAD CAME IN PRETTY GOOD FOR THIS CONVECTIVELY UNSETTLED
SITUATION. DID TWEAK POPS TO ADD MORE OF A DIURNAL CYCLE AND ALSO
TOWARD THE LATEST SPECIFICS FROM THE ECMWF. ONLY MADE MINOR TERRAIN
BASED ADJUSTMENTS FOR TEMPS THROUGHOUT THE EXTENDED PERIOD GIVEN THE
HIGH MOISTURE CONTENT.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 655 AM EDT WED AUG 7 2013
SOMEWHAT OF AN UNSETTLED TAF FORECAST. MODEL GUIDANCE IS NOT IN FULL
AGREEMENT ABOUT THE EXACT SET UP AND LOCATION OF TODAYS CONVECTIVE
DEVELOPMENT...NOR IS THERE MUCH AGREEMENT ON THE CIGS THROUGHOUT THE
DAY. BASED ON LATEST OBSERVATIONS...WHILE SOME LOCATIONS ARE STILL
EXPERIENCING MVFR OR LOWER CONDITIONS...TAF SITES SEEM TO BE TAKING A
UPWARD TREND. UNTIL ONSET OF PRECIP...AND PERHAPS EVEN AFTER...EXPECT
CIGS TO REMAIN ABOVE VFR. THERE IS STILL A CHANCE HOWEVER...THAT AS
WE GO INTO THE DAYTIME HOURS SOME OF THE CONVECTIVE DEVELOPMENT COULD
LOWER TO MVFR. PRECIP CHANCES WILL LESSON WITH LOSS OF DAYTIME
HEATING THIS EVENING...BUT VCSH WILL STILL BE WARRANTED. WHILE SOME
BR DEVELOPMENT IS POSSIBLE AFTER THIS POINT...CLOUD COVER COULD WORK
TO INHIBIT ITS DEVELOPMENT...SO WAS NOT CONFIDENT ENOUGH TO INCLUDE
IN TAFS THIS FAR OUT IN THE PERIOD. MUCH LIKE LAST NIGHT...FOG WILL
LIKELY OCCUR IN A FEW ISOLATED SPOTS AND REMAIN OUT OF THE TAF SITES.
BASED ON LOWERING CIGS THROUGHOUT THE NIGHT LAST NIGHT...COULD ALSO
EXPECT A SIMILAR SITUATION TONIGHT. BUT ONCE AGAIN...WITH SUCH LOW
MODEL CONFIDENCE AND BEING THIS FAR OUT...CHOSE NOT TO INCLUDE.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SBH
SHORT TERM...JMW
LONG TERM...GREIF
AVIATION...JMW
AREA FORECAST DISCUSSION
NWS JACKSON KY
957 AM EDT WED AUG 7 2013
.UPDATE...
ISSUED AT 956 AM EDT WED AUG 7 2013
NDFD AND ASSOCIATED PRODUCTS...INCLUDING ZFP HAVE BEEN UPDATED. THE
NEAR TERM MODELS ARE NOT HANDLING THIS MORNINGS CONVECTION VERY
WELL...AND AS SUCH THIS THROWS DOUBT INTO THE NEAR TERM GUIDANCE FOR
THE REST OF THE DAY INTO TONIGHT. THE 11Z HRRR SHOWED THE DEVELOPMENT
OF THE CONVECTION EARLY THIS MORNING BUT QUICKLY HAD IT DIE AWAY
BEFORE BRINGING AN ORGANIZED BAND OF CONVECTION ACROSS THE AREA FROM
LATE MORNING INTO EARLY AFTERNOON WITH ANOTHER ROUND OF ORGANIZED CONVECTION
FROM LATE AFTERNOON INTO THE EVENING. THE 12Z HRRR IS JUST COMING
IN...AND STILL NOT HANDLING THIS MORNINGS CONVECTION VERY WELL...BUT
IS LEANING TOWARDS MORE DISORGANIZATION IN THE CONVECTION FOR THIS
AFTERNOON.
THERE WILL BE CONSIDERABLE DEBRIS CLOUDINESS ACROSS THE AREA
TODAY...BUT EXPECT SOME BREAKS IN THE CLOUDS IN THE WAKE OF THE
SHOWERS AND THUNDERSTORMS THAT OCCUR THIS MORNING. THIS WOULD ALLOW
ADDITIONAL DESTABILIZATION WITH MORE AFTERNOON HEATING. WHERE BREAKS
HAVE OCCURRED IN CENTRAL KY TEMPERATURES HAVE JUMPED INTO THE UPPER
70S AND AS SUCH WILL INCREASE AFTERNOON MAXIMUM TEMPERATURES SEVERAL
DEGREES. WITH NUMEROUS SHOWERS ALREADY OCCURRING ACROSS THE AREA HAVE
INCREASED RAIN CHANCES FOR THIS MORNING IN ALL BUT THE FAR
NORTH...YIELDING NUMEROUS SHOWERS AND THUNDERSTORMS IN THE FORECAST
FOR TODAY IN MOST AREAS...RATHER THAN JUST FOR THIS AFTERNOON.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 356 AM EDT WED AUG 7 2013
THE ENTIRE FORECAST WILL BE PROGGED BY SUBTLE SHORTWAVES MOVING
EASTWARD FROM THE ROCKIES AND GREAT PLAINS...AND IMPACTING KY OR
SURROUNDING AREAS. FOR THE SHORT TERM...THE FOCUS WILL BE ON A SHORT
WAVE THAT MODEL CONSENSUS HAS REACHING WESTERN KY BY 18Z TODAY...AND
EASTERN KY IN THE EVENING AROUND 0Z. ANOTHER LARGER SHORTWAVE WILL
THEN APPROACH WESTERN KY AND MUCH OF TN THE FOLLOWING AFTERNOON ON
THURSDAY. BOTH OF THESE WAVES WILL TRANSLATE TO SURFACE INSTABILITY
AND THE EXPECTATION OF CONVECTIVE DEVELOPMENT.
STARTING WITH TODAY...A WARM FRONT THAT MOVED THROUGH LAST NIGHT HAS
ALLOWED FOR STRONG WAA AND A VAST INCREASE IN THE HUMIDITY VALUES.
WHILE EXPECTED CLOUD COVER TODAY WILL KEEP TEMPERATURES FROM RISING
TO THEIR FULL POTENTIAL...DEW POINTS ON THE OTHER HAND WILL RISE TO
THE LOW 70S...ALLOWING FOR HIGH HUMIDITY AND APPARENT TEMPERATURES
IN THE MID AND UPPER 80S IN SOME LOCATIONS. THE SHORTWAVE
APPROACHING FROM THE WEST WILL TRANSLATE TO A SURFACE LOW PRESSURE
SYSTEM TO THE NORTH OVER THE UPPER GREAT LAKES. AS THIS SHORTWAVE
AND ASSOCIATED LOW PRESSURE SYSTEM CONTINUE ON THEIR TREK
NORTHEAST...IT WILL PULL A LARGE COLD FRONT SEWARD ACROSS
MI/IN/IL/AND MO DURING THE AFTERNOON...NEARING THE OHIO VALLEY
WEDNESDAY NIGHT. WITH THE VERY MOIST AND UNSTABLE ENVIRONMENT
ALREADY AT PLAY DURING THE DAY TODAY...THE ISENTROPIC LIFT AHEAD OF
THE APPROACHING FRONT WILL BE ENOUGH TO KICK START CONVECTION ACROSS
THE AREA. WHILE MODELS ARE STILL SOMEWHAT LACKLUSTER ON THEIR
SOLUTION AGREEMENT...WILL GO WITH THE CONSENSUS THAT BEST PRECIP
POTENTIAL WILL BE IN THE FAR EASTERN PORTION OF THE CWA BETWEEN 15
AND 0Z TODAY. WITH GOOD DIRECTIONAL AND SPEED SHEAR...AS WELL AS
MARGINAL CAPE VALUES...COULD SEE STORMS DEVELOP ACROSS THE ENTIRE
CWA. WITH MOIST LOW LEVELS AND DRY AIR FILTERING IN THE MID AND UPPER
LEVELS...COULD SEE SOME POTENTIAL FOR STRONG WINDS AND SMALL HAIL
DEVELOPMENT IN ADDITION TO SOME HEAVY DOWNPOURS.
BEST CONVECTIVE ACTIVITY WILL DIE DOWN OVERNIGHT WITH LOSS OF
DAYTIME HEATING...BUT AS COLD FRONT JUST TO OUR NORTH BECOMES NEARLY
STATIONARY...THERE WILL BE ENOUGH INSTABILITY AND LIFT NEARBY TO
PREVENT DROPPING POPS BELOW CHANCES. THIS WILL BE REINFORCED BY THE
FACT THAT CLOUD COVER AND CONTINUED WARM AIR FILTERING IN FROM THE
SOUTH WILL PREVENT LOWS FROM DROPPING BELOW 70 IN MANY LOCATIONS.
THIS WILL RESULT IN A VERY SOUPY NIGHT WITH HUMIDITY VALUES RANGING
FROM 90 TO 100 PERCENT ACROSS MUCH OF THE REGION. ANY LITTLE THING
COULD BE ENOUGH TO INITIATE SOME SORT OF PRECIP IN SUCH AN
ENVIRONMENT AS A RESULT.
BY 12Z THURSDAY...THE NEXT SHORTWAVE TO IMPACT THE AREA WILL FIND
ITSELF OVER MISSOURI AND NORTHERN ARKANSAS. AT THE SURFACE...THIS
WILL BEGIN INTERACTING WITH THE STATIONARY SURFACE COLD FRONT AND
THE DAYTIME INSTABILITY...BRINGING AN INCREASE OF CONVECTION ACROSS
WESTERN KY IN THE MORNING...AND THEN ACROSS THE ENTIRE FRONTAL
BOUNDARY BY AFTERNOON...WITH PRECIP CHANCES EXPECTED TO IMPACT FROM
AS FAR WEST AS COLORADO...THEN POINTS EASTWARD...AND ACROSS THE
ENTIRETY OF THE EASTERN SEABOARD. ONCE AGAIN...MODEL CONSENSUS IS
PEGGING THE FAR EASTERN PORTIONS OF THE STATE FOR THE BEST QPF AND
PRECIP POTENTIAL...THOUGH IN SUCH AN ENVIRONMENT SCT TO WIDESPREAD
STORM DEVELOPMENT CAN BE EXPECTED JUST ABOUT ANYWHERE ACROSS THE
REGION. CAPE VALUES THIS DAY WILL BE MUCH MORE SUBSTANTIAL IN THE
EAST CENTRAL...WITH MOIST LOW LEVELS AND DRY AIR FILTERING IN ALOFT
DURING THE AFTERNOON HOURS. THE LATEST ECMWF IS ALSO SHOWING THAT
WHILE LAPSE RATES WILL STILL NOT BE THAT IMPRESSIVE...THERE WILL BE
A GOOD AREA OF QVECTOR CONVERGENCE THAT MOVES ACROSS THE STATE
THURSDAY AFTERNOON/EVENING. ALL THINGS BEING FACTORED IN...LATEST
NAM SOUNDINGS SUPPORT THE IDEA THAT WITH LITTLE IN THE WAY OF LAPSE
RATES AND PWAT VALUES NEARING 2 INCHES IN SOME PLACES...WILL PROBABLY
EXPECT MORE OF A HEAVY RAIN THREAT WITH THESE STORMS COMPARED TO
TODAY. SOME ISOLATED STRONGER STORMS CAN NOT BE RULED OUT HOWEVER.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 356 AM EDT WED AUG 7 2013
THE MODELS CONTINUE TO BE IN PRETTY GOOD AGREEMENT WITH THE OVERALL
PATTERN ALOFT FOR THE EXTENDED. LIKE LAST NIGHT...THE MAIN
DIFFERENCES REVOLVE AROUND SHORTWAVES AND MESOSCALE FEATURES THAT
ARE MORE DIFFICULT TO RESOLVE THIS FAR OUT. THE GENERAL PATTERN
STARTS WITH A DOMINANT TROUGH OVER SOUTH CENTRAL CANADA NORTH OF
FLAT RIDGING COVERING THE SOUTHERN TIER OF THE STATES. BETWEEN
THESE...RELATIVELY FAST FLOW WILL BRING ENERGY FROM THE WEST COAST
TO THE EAST PASSING THROUGH THE OHIO VALLEY. WHILE THE CORE OF THE
NORTHERN TROUGH MOVES EAST BY EARLY SATURDAY THE TROUGH ITSELF WILL
REFORM OVER THE WEEKEND AND ACTUALLY BUILD SOUTH TO ENCOMPASS THE
GREAT LAKES OHIO VALLEY BY 00Z TUESDAY. OVER OUR AREA THIS EVOLUTION
WILL BUCKLE THE INITIALLY ZONAL PATTERN INTO ONE OF NORTHWEST FLOW.
THROUGH IT ALL...KENTUCKY WILL HAVE TO DEAL WITH PASSING WAVES OF
MID LEVEL ENERGY ALONG WITH ANY THAT MAY BE CONVECTIVELY DRIVEN.
THIS SHOULD MEAN AN LARGELY UNSETTLED PERIOD OF WEATHER. DUE
TO THE GENERAL MODEL AGREEMENT...HAVE FAVORED A MODEL BLEND WITH A
BIT OF A LEAN TOWARD THE 00Z ECMWF.
SENSIBLE WEATHER WILL FEATURE AN EXTENDED PERIOD OF POTENTIALLY
EXCESSIVE RAINS AS A FRONTAL BOUNDARY AND HIGHER THAN NORMAL PW AIR
WILL REMAIN IN IN PLACE THROUGH THE WEEKEND. COMBINED WITH DAYTIME
INSTABILITY...AND SOME UPPER LEVEL SUPPORT...EACH DAY COULD TURN OUT
TO BE A WASHOUT WITH HEAVY RAIN FROM A COMPLEX OF SHOWERS AND
THUNDERSTORMS. HOWEVER...SIMILAR TO TODAY...SOME OF THESE PARAMETERS
MAY NOT COME TOGETHER AND A GOOD PORTION OF THE AREA COULD BE DRY
DESPITE THE SET UP. AS SUCH...THE FORECAST WILL CONSIST OF
HIGHER POP CHANCES DURING THE LATE AFTERNOON AND EARLY EVENING HOURS
WITH A DIMINISHMENT AT NIGHT THROUGH SUNDAY. OF COURSE...ANY MCS
ACTIVITY COULD EASILY EXTEND INTO THE NIGHT SO CANNOT GO DRY FOR
THESE TIMES EITHER. UNFORTUNATELY...WITH THE POTENTIAL FOR MCS
DEVELOPMENT THROUGH THE BULK OF THE EXTENDED...CONFIDENCE IS LOWER
THAN NORMAL FOR FORECAST SPECIFICS ASIDE FROM THE ACKNOWLEDGMENT OF
THE BUILT UP POSSIBILITIES. THEREFORE...THE FORECAST WILL CONSIST OF
RATHER HIGH POPS THROUGH THE WEEKEND...WITH LESS OF A THREAT ON
MONDAY AND TUESDAY IF THE NEW ECMWF IS RIGHT AND THE FRONT DROPS
SOUTH. ALONG WITH THE HIGH POPS WILL GO COOLER THAN NORMAL TEMPS...
THOUGH THE HIGH DEWPOINTS WILL MAKE IT FEEL SEVERAL DEGREES WARMER
THAN ACTUAL AIR TEMPERATURE. BASED ON THE 00Z ECMWF...HIGH PRESSURE
MAY BE ABLE TO PUSH IN AND SHOVE THE MORE HUMID AIR SOUTH FOR A GOOD
PORTION OF THE UPCOMING WEEK. UNTIL THEN...THOUGH...WE WILL BE AWASH
IN A MUGGY AIR MASS COMPLETE WITH MOST OF THE INGREDIENTS NEEDED FOR
HEAVY RAINS.
THE CR GRID LOAD CAME IN PRETTY GOOD FOR THIS CONVECTIVELY UNSETTLED
SITUATION. DID TWEAK POPS TO ADD MORE OF A DIURNAL CYCLE AND ALSO
TOWARD THE LATEST SPECIFICS FROM THE ECMWF. ONLY MADE MINOR TERRAIN
BASED ADJUSTMENTS FOR TEMPS THROUGHOUT THE EXTENDED PERIOD GIVEN THE
HIGH MOISTURE CONTENT.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 655 AM EDT WED AUG 7 2013
SOMEWHAT OF AN UNSETTLED TAF FORECAST. MODEL GUIDANCE IS NOT IN FULL
AGREEMENT ABOUT THE EXACT SET UP AND LOCATION OF TODAYS CONVECTIVE
DEVELOPMENT...NOR IS THERE MUCH AGREEMENT ON THE CIGS THROUGHOUT THE
DAY. BASED ON LATEST OBSERVATIONS...WHILE SOME LOCATIONS ARE STILL
EXPERIENCING MVFR OR LOWER CONDITIONS...TAF SITES SEEM TO BE TAKING A
UPWARD TREND. UNTIL ONSET OF PRECIP...AND PERHAPS EVEN AFTER...EXPECT
CIGS TO REMAIN ABOVE VFR. THERE IS STILL A CHANCE HOWEVER...THAT AS
WE GO INTO THE DAYTIME HOURS SOME OF THE CONVECTIVE DEVELOPMENT COULD
LOWER TO MVFR. PRECIP CHANCES WILL LESSON WITH LOSS OF DAYTIME
HEATING THIS EVENING...BUT VCSH WILL STILL BE WARRANTED. WHILE SOME
BR DEVELOPMENT IS POSSIBLE AFTER THIS POINT...CLOUD COVER COULD WORK
TO INHIBIT ITS DEVELOPMENT...SO WAS NOT CONFIDENT ENOUGH TO INCLUDE
IN TAFS THIS FAR OUT IN THE PERIOD. MUCH LIKE LAST NIGHT...FOG WILL
LIKELY OCCUR IN A FEW ISOLATED SPOTS AND REMAIN OUT OF THE TAF SITES.
BASED ON LOWERING CIGS THROUGHOUT THE NIGHT LAST NIGHT...COULD ALSO
EXPECT A SIMILAR SITUATION TONIGHT. BUT ONCE AGAIN...WITH SUCH LOW
MODEL CONFIDENCE AND BEING THIS FAR OUT...CHOSE NOT TO INCLUDE.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SBH
SHORT TERM...JMW
LONG TERM...GREIF
AVIATION...JMW
AREA FORECAST DISCUSSION
NWS CARIBOU ME
912 PM EDT THU AUG 8 2013
.SYNOPSIS...
A COLD FRONT WILL APPROACH FRIDAY...THEN CROSS THE REGION FRIDAY
NIGHT. HIGH PRESSURE WILL BUILD ACROSS THE REGION SATURDAY THROUGH
SUNDAY.
&&
.NEAR TERM /THROUGH FRIDAY/...
850 PM UPDATE: RADAR INDICATES A WEAKENING TREND OF CNVCTN OVR NW
ME AS IT MOVED EWRD TOWARD NE ME. HRRR MODEL SIMULATED HRLY RADAR
REF DOES SHOW OCNL HIER REF ECHOES IMPLYING ISOLD TSTMS LATER
TNGT...SO WE WILL LEAVE A MENTION OF ISOLD TSTMS FOR MOST OF THE
FA FOR THE REMAINDER OF THE NGT. OTHERWISE...WE AGAIN ADJUSTED
FCST HRLY TEMPS AFT LOADING OBSVD HRLY TEMPS FROM ACROSS THE
REGION. DO NOT PLAN ON MAKING ANY CHGS TO FCST LOW TEMPS ATTM...
BUT WE WILL NEED TO WATCH THAT OBSVD TEMPS KEEP LVL FROM THIS
POINT ON...SINCE THEY ARE FAR FROM FCST LOWS. WITH CLD CVR AND
FOG ASSOCIATED WITH HIGH DWPT AIR...TEMPS SHOULD STAY UP FOR THE
REMAINDER OF THE OVRNGT.
510 PM UPDATE: RADAR INDICATES A GROUP OF HEAVIER SHWRS WITH OCNL
LGTNG AND THUNDER MOVG E FROM ERN QB TO MSLY JUST S OF CLAYTON LAKE
IN NW AROOSTOOK COUNTY. THIS ACTIVITY SHOULD WEAKEN AS IT GRAZES
NRN PISCATAQUIS COUNTY TOWARD ERN AROOSTOOK COUNTY...WITH LAPSE
DATA INDICATING PROGRESSIVELY LOWER SBCAPE IN THIS DIRECTION. OTHER
TSTMS FROM ERN QB COULD WORK INTO NRN SOMERSET OR WRN PISCATAQUIS
COUNTY OVR THE NEXT COUPLE OF HRS AS THEY MOVE FROM A SBCAPE
ENVIRONMENT OF 1000J+/KG...BUT ALSO SHOULD SLOWLY WEAKEN AS THEY
MOVE FURTHER E INTO OUR FA. OTHERWISE...WE INCREASED POPS FOR FRI...
SPCLY FRI AFTN CLOSER TO 100 PERCENT FOR MUCH OF THE FA GIVEN THE
AMOUNT OF QPF XPCTD THIS PD...WHICH IS GREATER THAN A HALF INCH.
LASTLY...WE ADJUSTED FCST HRLY TEMPS THIS EVE BASED ON 5 PM OBSVD
TEMPS...WHICH SHOWED TEMPS IN THE LOWER 70S OVR NRN SOMERSET
COUNTY NEAR THE QB BORDER. PART OF THIS ADJUSTMENT WAS TO RAISE
FORMER AFTN HI TEMPS.
ORGNL DISC: STABLE LOW CLOUDS COVER MOST OF THE REGION AND WILL
CONTINUE THROUGH THE NIGHT. THIS WILL LIMIT LOWS TO THE LOW TO MID
60S. AS AN UPPER LEVEL LOW IN ONTARIO DRAWS CLOSER
OVERNIGHT...SOME ELEVATED INSTABILITY WILL DEVELOP AND SOME
ISOLATED THUNDERSTORMS WILL BE POSSIBLE. THE STABLE LOW CLOUDS
HAVE BROKEN UP IN NORTHERN PISCATAQUIS AND NORTHERN SOMERSET
COUNTIES THIS AFTERNOON AND THIS IS GENERATING SOME INSTABILITY
THAT MAY PRODUCE A FEW STRONG THUNDERSTORMS THIS EVENING. HAVE
MAINTAINED GUSTY WIND AND SMALL HAIL WORDING FOR THESE REMOTE
AREAS FOR THIS EVENING.
AS THE FRONT DRAWS CLOSER...A BROAD AREA OF HEAVY RAIN AND
THUNDERSTORMS WILL MOVE NORTHEAST ALONG THE FRONT FROM THE OHIO
VALLEY AND REACH SOUTHERN PORTIONS OF THE FORECAST AREA LATER
TONIGHT. THIS RAIN WILL SPREAD NORTHWARD ACROSS THE ENTIRE
FORECAST AREA TOMORROW. MOST AREAS SHOULD EXPECT A STEADY RAIN
FRIDAY WITH PERIODS OF HEAVY RAIN...POTENTIALLY DUE TO
THUNDERSTORMS. THE HEAVIEST RAIN AT THIS POINT IS EXPECTED DOWN
EAST WITH STORM TOTALS WELL OVER AN INCH. THUNDERSTORMS WILL
INCREASE RAINFALL TOTALS SIGNIFICANTLY. CONFIDENCE IS NOT HIGH
ENOUGH FOR A FLOOD WATCH AT THIS POINT...BUT WILL CONSIDER
ISSUANCE AFTER A LOOK AT THE 00Z MODEL RUNS AND PLACEMENT OF THE
HEAVIEST PRECIP BECOMES CLEARER. PWATS...A LLJ...INSTABILITY ALOFT
AND A DEEP WARM CLOUD LAYER ALL HIGHLIGHT THE POTENTIAL FOR FLOODING.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
LOW PRESSURE WILL TRACK NORTHWEST OF MAINE FRIDAY NIGHT DRAWING A
COLD FRONT ACROSS THE FORECAST AREA. AN AREA OF RAIN WILL CROSS
THE REGION IN ADVANCE OF THE FRONT...WITH AN EVENING THUNDERSTORM
ALSO POSSIBLE. THE STEADIEST RAINS EARLY FRIDAY NIGHT WILL
GENERALLY OCCUR ACROSS EASTERN AND DOWNEAST PORTIONS OF THE
FORECAST AREA...THOUGH RAINFALL AMOUNTS AND THE EXACT LOCATION OF
THE HEAVIEST RAINS ARE STILL UNCERTAIN. AN UPPER LOW WILL TRACK
NORTH OF MAINE SATURDAY WHICH COULD KEEP THE SLIGHT CHANCE OF A
SHOWER ACROSS THE NORTH AND MOUNTAINS INTO SATURDAY AFTERNOON.
OTHERWISE...PARTLY/MOSTLY SUNNY SKIES ARE EXPECTED ACROSS THE
REGION SATURDAY. HIGH PRESSURE WILL THEN BUILD ACROSS THE REGION
SATURDAY NIGHT THROUGH SUNDAY NIGHT WITH PARTLY CLOUDY/MOSTLY
CLEAR SKIES ACROSS NORTHERN AREAS...WITH GENERALLY MOSTLY CLEAR
SKIES DOWNEAST. HIGH TEMPERATURES WILL BE AT NEAR NORMAL LEVELS
SATURDAY/SUNDAY...WITH SLIGHTLY BELOW NORMAL LEVEL LOW
TEMPERATURES SATURDAY NIGHT/SUNDAY NIGHT.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
CLOUDS WILL INCREASE MONDAY WITH A CHANCE OF SHOWERS ARRIVING BY
LATE DAY IN ASSOCIATION WITH THE NEXT FRONTAL SYSTEM. THIS SYSTEM
MOVES THROUGH LATER MONDAY NIGHT INTO TUESDAY WITH THE BEST CHANCE
OF RAIN AND SHOWERS ARRIVING DURING THIS TIME. FOLLOWING THIS
SYSTEM EXPECT AN IMPROVING TREND WEDNESDAY INTO THURSDAY HOWEVER
WEDNESDAY WILL STILL FEATURE THE SLIGHT RISK OF A SHOWER OR TWO
DUE TO THE LINGERING UPPER LEVEL TROUGH. TEMPERATURES THROUGH THE
LONG RANGE WILL BE NEAR OR BELOW AVERAGE FOR THIS TIME OF YEAR.
&&
.AVIATION /22Z THURSDAY THROUGH TUESDAY/...
NEAR TERM: IFR AND MARGINAL MVFR CEILINGS WILL BECOME LIFR TONIGHT
WITH THICKER FOG POSSIBLE TOWARDS BHB. IFR CEILINGS CONTINUE
FRIDAY IN RAIN WITH EMBEDDED THUNDERSTORMS. THUNDERSTORMS ARE ALSO
POSSIBLE OVERNIGHT WITH SOME POTENTIALLY SEVERE THUNDERSTORMS TO
FL350 JUST WEST OF GNR THIS EVENING.
SHORT TERM: MVFR/IFR CONDITIONS ARE EXPECTED ACROSS THE REGION
EARLY FRIDAY NIGHT...WITH IMPROVING CONDITIONS OVERNIGHT.
OCCASIONAL MVFR CONDITIONS ARE POSSIBLE ACROSS NORTHERN AREAS
EARLY SATURDAY. OTHERWISE...VFR CONDITIONS ARE EXPECTED ACROSS THE
REGION SATURDAY THROUGH SUNDAY NIGHT. EXPECT VFR THROUGH MOST OF
MONDAY WITH A PERIOD OF MVFR/IFR LIKELY BY LATER MONDAY NIGHT INTO
TUESDAY DUE TO SHOWERS AND LOW CEILINGS.
&&
.MARINE...
NEAR TERM: FOG IS EXPECTED TO INCREASE TONIGHT AND HAVE ADDED
AREAS OF FOG FOR TONIGHT AND TOMORROW. MODEL GENERATED WINDS AND
SEAS CONTINUE TO INITIALIZE TOO HIGH AND HAVE ADJUSTED DOWN. WILL
NOT ISSUE A SMALL CRAFT FOR HAZARDOUS SEAS AT THIS TIME AS SEAS
SHOULD STAY UNDER 5 FEET THROUGH FRIDAY.
SHORT TERM: SMALL CRAFT ADVISORY LEVEL SEAS ARE POSSIBLE FRIDAY
NIGHT AND SATURDAY. WINDS/SEAS ARE THEN EXPECTED TO BE BELOW SMALL
CRAFT ADVISORY LEVELS SATURDAY NIGHT THROUGH MONDAY. VISIBILITIES
WILL BE REDUCED IN RAIN AND FOG FRIDAY NIGHT. SCA CONDITIONS DUE
TO WINDS AND SEAS WILL BE POSSIBLE LATER TUESDAY INTO TUESDAY
NIGHT AS A FRONTAL SYSTEM MOVES THROUGH. THESE CONDITIONS DIMINISH
WEDNESDAY.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...VJN
SHORT TERM...NORCROSS
LONG TERM...FITZSIMMONS
AVIATION...VJN/NORCROSS
MARINE...VJN/NORCROSS
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
302 PM EDT WED AUG 7 2013
.SYNOPSIS...
HIGH PRESSURE WILL REMAIN PARKED OFFSHORE THROUGH THE END OF THE
WEEK. SOUTHERLY RETURN FLOW AROUND THE HIGH WILL DRAW TROPICAL
MOISTURE UP THE EASTERN SEABOARD. LOW PRESSURE MOVING EAST THROUGH
CANADA LATE IN THE WEEK WILL DRAG A COLD FRONT SOUTHEAST INTO THE
MID ATLANTIC SATURDAY. THAT FRONT WILL STALL OVER THE AREA INTO
EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
A V-SHAPED AREA OF CLEARING OVER THE WRN SECTIONS OF THE CWA -
THE WV PORTION OF THE APLCNS - HAS RESULTED IN ENOUGH INSTABILITY
COMBINING W/ A WEAK LEE TROUGH TO DEVELOP A HANDFUL OF TSTMS.
ATTM...THESE CELLS ARE TRUDGING ALONG THE LOW LEVEL BOUNDARY
STATIONED FROM NEAR ELKINS WV TO AROUND WINCHESTER VA. POCKETS OF
CLEARING ALSO OCCURRING OVER THE NRN VA PIEDMONT AND I-95
CORRIDOR...WHERE NUMEROUS AND VERY SMALL-SCALE SHOWERS ARE
DRIFTING OFF TO THE NE.
HAD THERE NOT BEEN THE SOLID STRATUS DECK FOR MUCH OF THE
DAY...THIS TYPE OF ACTIVITY WOULD LIKELY BE MUCH MORE WIDESPREAD
AND STRONGER...GIVEN THE DEEP MID-LEVEL DRY LAYER AND DECENT LAPSE
RATES. WITH SEVERAL MORE HRS OF DAYTIME LEFT...AREAS THAT CONTINUE
TO CLEAR OUT WILL ALSO SEE SOME OF THIS SCATTERED SHOWER/ISOLATED
TSTM ACTIVITY DEVELOP. THE STRONGEST OF THIS ACTIVITY WILL LIKELY
BE LIMITED TO THE POTOMAC HIGHLANDS/APLCNS AND PARTS OF THE NRN VA
SHEN VLY THRU THE AFTN/EVE HRS.
THE UPPER LEVEL FORCING AND DYNAMICS ARE - AND WILL CONTINUE TO BE
MUCH STRONGER THAN THE LOW LEVELS...WHICH MEANS THAT VERY LITTLE
LOW LEVEL INTERACTIONS WILL MAKE FOR ONLY A FEW TSTM CELLS BUT THE
ONES THAT DEVELOP WILL HAVE HEFTY SUPPORT FOR MAINTENANCE. THE
FAVORABLE BULK SHEER WILL ALSO...IN PART...MAKE UP FOR THE
RELATIVELY LOW INSTABILITY.
IN VARIOUS FORMS AND DEPICTIONS...THE HRRR AND OTHER LOCAL
GUIDANCE CONTINUE TO DEVELOPING THE FAIRLY RAGGED AND DISORGANIZED
CONVECTIVE LINES IN NRN OH...STRENGTHEN AND DRAG THEM ACROSS THE
REMAINDER OF WRN AND CNTRL PA TOWARD THE LATE NIGHT HRS TONIGHT.
EACH RUN A LITTLE DIFFERENT BUT STILL HIGHLIGHT THE MASON-DIXON
LINE AND THE TIER OF NRN MD COUNTIES ALONG IT AS THE NRN EXTENT OF
WHERE THIS LINE COULD SWING ACROSS. KEPT HIGHER POPS ACROSS THE
NRN TIER THIS EVE/TONIGHT FOR THIS EVENTUALITY. THOUGH MUCH OF THE
LINE COULD DISSIPATE AND BECOME STRATIFORM -SHRA...GUSTY WINDS
FROM THE UPPER LEVELS COULD BE A POSSIBILITY FROM EVEN POCKETS
OF HEAVY DOWNPOURS.
RAISED THE NEAR-TERM FORECAST TEMPS A COUPLE OF DEGREES W/ THE
QUICK DISSIPATION OF THE STRATUS DECK. MOST AREAS ARE NOW CLIMBING
AT LEAST INTO THE L80S. DEWPOINTS ARE ALSO CHARGING UP INTO THE
U60S AND L70S...MAKING FOR WHAT WILL BE A FAIRLY HUMID OVERNIGHT
PERIOD.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
THURSDAY BOTH THE EURO AND THE GFS BRING A TROUGH INTO THE REGION
FROM THE WEST. IT WILL BE ENOUGH TO AMP UP CHANCES OF THUNDER TO
LIKELY ACROSS ALL BUT SOUTHERN MD AND CENTRAL VA. WITH PRECIPITABLE
WATER FORECAST TO BE AROUND 2 INCHES AND WITH A FEW HINDERED OF
CAPE...THERE COULD BE SOME ISOLATED FLOODING ISSUES OR SEVERE
THREAT. NWS STORM PREDICTION CENTER MAINTAINS OUR AREA IN THE 5
PERCENT CHANCE FOR A FEW SEVERE STORMS ON THU.
FRI INTO FRI NIGHT WEAK TROF REMAINS OVER THE AREA. WILL MAINTAIN
CHANCE POPS OF TSTMS FOR THAT DIFFUSE FORCING. STILL...THERE IS
ENOUGH CAPE FOR A FEW ISOLATED SEVERE STORMS POSSIBLE. SPC HAS 5
PERCENT AGAIN.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
SATURDAY LOW PRESSURE WILL BE TRAVELING EAST THROUGH EASTERN
CANADA. THE ASSOCIATED COLD FRONT WILL ENTER OUR AREA ON
SATURDAY...BUT WILL LIKELY STALL OVER OR VERY NEAR OUR AREA INTO
EARLY NEXT WEEK. THAT WILL RESULT IN CHC TO SLIGHT CHC POPS FOR
TSTMS RIGHT THRU THIS PART OF THE FORECAST. TEMPS WILL BE NEAR
NORMAL. AT THE MOMENT...SATURDAY LOOKS LIKE THE WARMEST DAY WITH
HIGHS IN THE UPPER 80S TO LOWER 90S ACROSS THE REGION...BUT THAT
WILL DEPEND ON THE FRONT.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
BREAKS IN THE LOW STRATUS STARTING TO INCH NWD ACROSS THE NRN VA
PIEDMONT AND SHOULD BE SPREADING TOWARD THE DC AREA EARLY THIS
AFTN. CIGS WILL IMPROVE TO MVFR DURING THIS AFTN AS DAYTIME MIXING
DEEPENS. LATEST GUIDANCE SHOWS THIS AFTN MAINLY VFR.
TEMPORARY/LOCAL RESTRICTIONS POSSIBLE THOUGH IN HEAVIER SHRA AND
TSRA. TSRA THIS AFTN MAINLY ISO TO SCT.
LOW CLOUDS WILL TRY TO REDEVELOP AGAIN LATE TNGT...BUT LLVL FLOW
VEERS FROM THE SW SO SLIGHTLY DRIER AIR MAY LIMIT THIS POTENTIAL.
MOIST SLY RETURN FLOW WILL BE ACCOMPANIED BY DAILY CHANCES FOR SHRA
AND TSRA DURING THE REST OF THE WEEK...WITH THE GREATEST CHANCES ON
THURSDAY. THE POTENTIAL IS THERE FOR PERIODS OF LOW CLOUDS AND FOG
EACH NGT/ERY MRNG GIVEN THE MOIST BOUNDARY LAYER IN PLACE. A COLD
FRONT MOVES INTO THE REGION ON SATURDAY AND STALLS WITH CONTINUED
ISOLATED TO SCT TSTMS INTO EARLY NEXT WEEK.
&&
.MARINE...
SLY CHANNELING WILL STRENGTHEN DURING THE AFTN HRS OVER THE BAY.
SCA IN EFFECT FOR MOST OF THE MD CHSPK BAY.
SMALL CRAFT ADVISORIES ARE POSSIBLE AGAIN THURSDAY NIGHT...MAINLY ON
THE CENTRAL BAY AND LOWER TIDAL POTOMAC.
VERY LOW WIND SPEEDS ARE EXPECTED EARLY NEXT WEEK AS THE FRONT
STALLS OVER OR NEAR THE WATERS.
&&
.TIDES/COASTAL FLOODING...
AFTER A MORNING OF NEARLY 1.5FT POSITIVE TIDAL ANOMALIES...
SOMEWHAT OF A DECREASE TOWARD THE AFTN H.T. CYCLES. ANOMALIES
AROUND CLOSER TO ONE FT...WHICH MAY HOLD STEADY INTO THE OVERNIGHT
HRS. WILL MONITOR THE LATEST TRENDS AND THE OVERNIGHT SLY
CHANNELING WIND CONTRIBUTION FOR ADZY POTENTIAL.
SLY FLOW AND NEAR NEW MOON LUNAR CYCLE WILL CONTINUE THROUGH THE END
OF THE WEEK AS HIGH PRESSURE REMAINS OFF THE EAST COAST. THE HIGHER
OF THE TWO HIGH TIDES EACH DAY WILL BE THE ONE TO WATCH FOR
POTENTIAL MINOR TIDAL FLOODING.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR ANZ531>533-
539>542.
SMALL CRAFT ADVISORY FROM 11 AM TO 6 PM EDT THURSDAY FOR
ANZ530>534-537>543.
SMALL CRAFT ADVISORY UNTIL 6 AM EDT THURSDAY FOR ANZ534-537-
543.
&&
$$
UPDATE...GMS
PREV DISCUSSION...JRK/CAS
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
240 AM EDT WED AUG 7 2013
.SYNOPSIS...
ISSUED AT 240 AM EDT WED AUG 7 2013
A COLD FRONT WILL BRING STRONG TO SEVERE THUNDERSTORMS FROM EARLY
THIS MORNING THROUGH EARLY AFTERNOON WITH DAMAGING WIND GUSTS BEING
THE PRIMARY SEVERE WEATHER THREAT. MAINLY FAIR WEATHER WITH
SEASONABLE TEMPERATURES IS ANTICIPATED LATE THIS WEEK THROUGH THE
WEEKEND ALTHOUGH A COLD FRONT WILL BRING A SMALL CHANCE OF A SHOWER
ON FRIDAY.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY AFTERNOON)
ISSUED AT 240 AM EDT WED AUG 7 2013
OUR PRIMARY SHORT TERM FCST CHALLENGE IS TO DETERMINE SEVERE WX
POTENTIAL TODAY.
RGNL RADAR TRENDS EARLY THIS MORNING SHOW A VERY WELL DEVELOPED MCS
WITH HIGH WINDS OVER EAST CENTRAL WI AND WEST CENTRAL LAKE MI. THESE
STORMS WILL MOVE INTO OUR NW FCST AREA AND POTENTIALLY BRING
DAMAGING WIND GUSTS DURING THE EARLY MORNING HOURS.
EXTRAPOLATION OF RADAR TRENDS CORROBORATED WITH 00Z 4KM WRF-NMM SIM
Z GUIDANCE AND COLD FRONTAL TIMING SUGGESTS THAT THUNDERSTORMS ARE
LIKELY TO DEVELOP ACROSS OUR AREA FROM THE EARLY MORNING HOURS TODAY
THROUGH AROUND 18Z THIS AFTERNOON.
STRONG TO SEVERE STORMS ARE LIKELY THIS MORNING AND EARLY AFTERNOON
GIVEN SUFFICIENT MOISTURE... LIFT FROM THE FRONT AND WEAK TO
POTENTIALLY MODERATE INSTABILITY. 0-6KM BULK SHEAR VALUES OF 35-40
KTS ARE ALSO FAVORABLE FOR STRONG TO SEVERE STORMS FROM EARLY THIS
MORNING THROUGH AROUND TO SHORTLY AFTER MIDDAY. DAMAGING WIND GUSTS
ARE THE PRIMARY SVR WX THREAT.
THE REMAINDER OF THE SHORT TERM FCST PERIOD LOOKS TRANQUIL AS A HIGH
PRESSURE RIDGE BUILDS IN TONIGHT THROUGH TOMORROW. ANOTHER COLD
FRONT WILL MOVE THROUGH OUR AREA ON FRIDAY BRINGING A REINFORCING
SHOT OF COOLER AIR AND A SLIGHT CHC OF A SHOWER OR STORM.
.LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY)
ISSUED AT 245 AM EDT WED AUG 7 2013
NO IMPACT WEATHER IN THE EXTENDED AS COOL CANADIAN SURFACE HIGH IS
IN CONTROL THROUGH THE WEEKEND. A FEW SHOWERS ARE POSSIBLE EARLY
NEXT WEEK AS ANOTHER REINFORCING COLD FRONT MOVES THROUGH.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1136 PM EDT TUE AUG 6 2013
THE MAIN QUESTION IS THE CONVECTION OVER EASTERN MINNESOTA AND
WESTERN WISCONSIN... CAN IT REACH SOUTHWEST LOWER MICHIGAN BEFORE
DISSIPATING? THE HRRR CONTINUES TO SLOW DOWN THE ARRIVAL TIME OF
THE CONVECTION INTO SOUTHWEST MICHIGAN. USING THE TIMING TOOL
SEVERAL TIME I FIND THE SAME TREND... EVEN WITH THE 45 KNOT SPEED
OF THE CONVECTION... IT IS SLOWER EACH TIME I CHECK. AS OF 0330Z
IT NOW SUGGESTS MKG AROUND 10Z AND GRR AROUND 11Z AND 12Z FOR AZO
AND BTL. SO I SLOWED THE TIMING IN THE TAFS.
THE CONVECTION ON THE COLD FRONT SHOULD STILL DEVELOP EAST OF
US-131 EARLY TO MID AFTERNOON. IT MAY IMPACT LAN AND JXN MORE SO
THAN AZO AND BTL EVEN SO I KEPT THE VCTS IN THOSE TAF SITES...
AZO...BTL...LAN AND JXN JUST IN CASE.
&&
.MARINE...
ISSUED AT 240 AM EDT WED AUG 7 2013
WINDS WILL VEER TO THE WEST THEN NORTHWEST TO NORTH TODAY BEHIND THE
COLD FRONT AND CAUSE WAVE HEIGHTS TO RAMP UP SOMEWHAT. HOWEVER WINDS
AND WAVE HEIGHTS SHOULD REMAIN BELOW SCA CRITERIA. THUNDERSTORMS
WITH HIGH WINDS WILL POSE A HAZARD TO MARINERS THIS MORNING.
&&
.HYDROLOGY...
ISSUED AT 240 AM EDT WED AUG 7 2013
NO SIGNIFICANT HYDRO ISSUES ANTICIPATED WITH RAINFALL TODAY NOT
EXPECTED TO BE VERY HEAVY IN TERMS OF BASIN AVERAGE QPF AMOUNTS...
THOUGH HEAVIEST STORMS COULD CERTAINLY PRODUCE LOCALLY HEAVY
RAINFALL AND SOME URBAN AND SMALL STREAM TYPE FLOODING ISSUES THIS
MORNING AND EARLY AFTERNOON. BASIN AVERAGE QPF AMOUNTS OF ONLY
AROUND A QUARTER TO THREE QUARTERS OF AN INCH ARE EXPECTED BUT
HEAVIEST STORMS COULD EASILY PRODUCE LOCALLY HIGHER AMOUNTS OF AN
INCH OR TWO.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...LAURENS
SHORT TERM...LAURENS
LONG TERM...OSTUNO
AVIATION...WDM
HYDROLOGY...LAURENS
MARINE...LAURENS
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
935 PM CDT Thu Aug 8 2013
.UPDATE...
Issued at 929 PM CDT THU AUG 8 2013
Heavy rain threat has ended for the far southern two tier of counties
for the rest of tonight as well as Friday. Convection has sprouted
further south than the previous two nights and expect it to spread
across OK/AR tonight with a gradual shift northeast into southern
KS/MO late tonight through Friday morning. Latest NAM/RAP/local WRF
continue to show little if any QPF over the CWA tonight. HRRR has
been the best predictor of the 12-15hr period for the past several
days/nights and it too keeps the CWA basically dry. Will roll back
PoPs and go with isolated light showers overnight except increase
them over the CWA as the northern edge of the precipitation shield of
the convective complex spreads northeast.
Have also adjusted PoPs a bit on Friday to reflect the lower
confidence on rain chances. The southern CWA still retains the
highest PoPs but heavy rainfall not likely.
UPDATE Issued at 730 PM CDT THU AUG 8 2013
Relying on radar trends and HRRR which has proven to have a better
track record over the next 12 hours. Heavy rain looks like it will
shift into southern MO and out of the CWA. Will wait to see what the
00z NAM looks like before pulling the plug on the Flash Flood Watch.
For now will lower PoPs across the board with best bet for measurable
rain over the far southern counties. Sprinkles/light showers possible
through mid evening over eastern KS/west central and northwest MO.
&&
.SHORT TERM...(This Evening through Friday)
Issued at 300 PM CDT THU AUG 8 2013
Tonight/Friday: High uncertainty exists within forecast the next 24
hours. Current model initialization have done a poor job with
short-term trends, lending to decreased confidence in solutions for
tonight into Friday. Well-defined MCV per visible satellite and
radar trends continues to spin over central Kansas. Over the past
hour, an increasing trend of echoes has been noted over portions of
Kansas, Missouri, and southern Nebraska. The coverage, persistence,
and intensity of this activity remain quite uncertain. Do not
anticipate this activity to become heavy and should only persist for
a few more hours, otherwise could have a moderate effect to going
forecast. Dry air from H7-H85 has prevented an eastward expanse to
precipitation since this morning, and models show this layer only
gradually moistening through the overnight hours. Current surface
analysis shows frontal boundary sagging southward to near the
Oklahoma-Kansas border, with profiler data showing the H85 front
just south of the forecast area. Virtually every model solution
suggests a southward shift of the heavy precipitation corridor for
tonight/Friday, and this along with current surface/profiler data,
is compelling enough to subsequently shift heavy rain axis to the
south by at least 50 miles. Current forecast places up to one inch
of rainfall in the far southern sections of the CWA, with decreasing
amounts with northward extent. Therefore, will cancel flash flood
watch for areas along Interstate 70, and continue the southern two
rows of counties as a conditional threat if a heavy rain corridor
can make it this far north. Upper disturbance over Colorado will
make its way eastward into the Central Plains tonight, but will also
begin to weaken some with time. Still, with some increase in ascent
and close proximity to surface/elevated boundaries, cannot rule out
southern sections of the forecast area receiving moderate to
occasionally heavy rainfall late tonight into Friday. Decreasing
probabilities of rain are expected after noon Friday.
.LONG TERM...(Friday Night through Thursday)
Issued at 300 PM CDT THU AUG 8 2013
Precipitation chances will focus primarily south of the forecast
area during much of the weekend as flow becomes more zonal and the
primary focus for precipitation becomes a stationary boundary near
the MO/AR border. Ongoing precipitation Friday could linger into
Friday night as the boundary sinks back to the south; afterward,
just a few stray showers and storms possibly brushing far southern
portions of the CWA will bring the only chance of precipitation
through Sunday afternoon. Temperatures this weekend will recover to
near normal with a few breaks of sunshine Saturday and surface winds
returning to the south on Sunday.
As upper-level low pressure deepens across northern Canada and the
pattern transitions into northwest flow, most models bring a weak
shortwave trough into northwest Missouri on Sunday night into early
Monday. This feature could bring in a quick shot of precipitation
and a weak frontal boundary as it pushes east southeast; however,
forcing looks fairly weak and should keep rainfall amounts low. The
boundary may again become stationary across southern Missouri and
allow rainfall chances to linger into Tuesday, but will focus
generally south of the CWA. Then for the remainder of the forecast
period, generally dry conditions are expected with the boundary
remaining south of the region and the trough in the east keeping
most northern disturbances separate from the best moisture. High
temperatures will also be a few degrees below normal next week, as a
result of the boundary remaining to the south and northwest flow
helping a bit cooler air filter down from the northern Plains.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday Evening)
Issued at 635 PM CDT THU AUG 8 2013
Model`s have been having problems of late attempting to handle
mesoscale disturbances and their associated convection. Convective
complex which dissipated as it tracked through west central MO has
left behind considerable subsidence which has suppressed convection
all day. Short range convective allowing model, HRRR, has shown to be
the superior model over a 12-15hr period and that plus radar and
diurnal trends will be relied on heavily. So, VFR conditions with
cigs aoa 8k ft with isolated evening sprinkles/light showers possible
over east central KS/west central MO. Could also see the same Friday
afternoon.
Heavy rain and thunderstorm threat should reside across southern KS
and southern MO tonight/Friday morning.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
UPDATE...MJ
SHORT TERM...Blair
LONG TERM...Laflin
AVIATION...MJ
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
734 PM CDT Thu Aug 8 2013
.UPDATE...
Issued at 730 PM CDT THU AUG 8 2013
Relying on radar trends and HRRR which has proven to have a better
track record over the next 12 hours. Heavy rain looks like it will
shift into southern MO and out of the CWA. Will wait to see what the
00z NAM looks like before pulling the plug on the Flash Flood Watch.
For now will lower PoPs across the board with best bet for measurable
rain over the far southern counties. Sprinkles/light showers possible
through mid evening over eastern KS/west central and northwest MO.
&&
.SHORT TERM...(This Evening through Friday)
Issued at 300 PM CDT THU AUG 8 2013
Tonight/Friday: High uncertainty exists within forecast the next 24
hours. Current model initialization have done a poor job with
short-term trends, lending to decreased confidence in solutions for
tonight into Friday. Well-defined MCV per visible satellite and
radar trends continues to spin over central Kansas. Over the past
hour, an increasing trend of echoes has been noted over portions of
Kansas, Missouri, and southern Nebraska. The coverage, persistence,
and intensity of this activity remain quite uncertain. Do not
anticipate this activity to become heavy and should only persist for
a few more hours, otherwise could have a moderate effect to going
forecast. Dry air from H7-H85 has prevented an eastward expanse to
precipitation since this morning, and models show this layer only
gradually moistening through the overnight hours. Current surface
analysis shows frontal boundary sagging southward to near the
Oklahoma-Kansas border, with profiler data showing the H85 front
just south of the forecast area. Virtually every model solution
suggests a southward shift of the heavy precipitation corridor for
tonight/Friday, and this along with current surface/profiler data,
is compelling enough to subsequently shift heavy rain axis to the
south by at least 50 miles. Current forecast places up to one inch
of rainfall in the far southern sections of the CWA, with decreasing
amounts with northward extent. Therefore, will cancel flash flood
watch for areas along Interstate 70, and continue the southern two
rows of counties as a conditional threat if a heavy rain corridor
can make it this far north. Upper disturbance over Colorado will
make its way eastward into the Central Plains tonight, but will also
begin to weaken some with time. Still, with some increase in ascent
and close proximity to surface/elevated boundaries, cannot rule out
southern sections of the forecast area receiving moderate to
occasionally heavy rainfall late tonight into Friday. Decreasing
probabilities of rain are expected after noon Friday.
.LONG TERM...(Friday Night through Thursday)
Issued at 300 PM CDT THU AUG 8 2013
Precipitation chances will focus primarily south of the forecast
area during much of the weekend as flow becomes more zonal and the
primary focus for precipitation becomes a stationary boundary near
the MO/AR border. Ongoing precipitation Friday could linger into
Friday night as the boundary sinks back to the south; afterward,
just a few stray showers and storms possibly brushing far southern
portions of the CWA will bring the only chance of precipitation
through Sunday afternoon. Temperatures this weekend will recover to
near normal with a few breaks of sunshine Saturday and surface winds
returning to the south on Sunday.
As upper-level low pressure deepens across northern Canada and the
pattern transitions into northwest flow, most models bring a weak
shortwave trough into northwest Missouri on Sunday night into early
Monday. This feature could bring in a quick shot of precipitation
and a weak frontal boundary as it pushes east southeast; however,
forcing looks fairly weak and should keep rainfall amounts low. The
boundary may again become stationary across southern Missouri and
allow rainfall chances to linger into Tuesday, but will focus
generally south of the CWA. Then for the remainder of the forecast
period, generally dry conditions are expected with the boundary
remaining south of the region and the trough in the east keeping
most northern disturbances separate from the best moisture. High
temperatures will also be a few degrees below normal next week, as a
result of the boundary remaining to the south and northwest flow
helping a bit cooler air filter down from the northern Plains.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday Evening)
Issued at 635 PM CDT THU AUG 8 2013
Model`s have been having problems of late attempting to handle
mesoscale disturbances and their associated convection. Convective
complex which dissipated as it tracked through west central MO has
left behind considerable subsidence which has suppressed convection
all day. Short range convective allowing model, HRRR, has shown to be
the superior model over a 12-15hr period and that plus radar and
diurnal trends will be relied on heavily. So, VFR conditions with
cigs aoa 8k ft with isolated evening sprinkles/light showers possible
over east central KS/west central MO. Could also see the same Friday
afternoon.
Heavy rain and thunderstorm threat should reside across southern KS
and southern MO tonight/Friday morning.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...FLASH FLOOD WATCH from Midnight CDT tonight through Friday
morning FOR KSZ057-060.
MO...FLASH FLOOD WATCH from Midnight CDT tonight through Friday
morning FOR MOZ043>046-053-054.
&&
$$
UPDATE...MJ
SHORT TERM...Blair
LONG TERM...Laflin
AVIATION...MJ
AREA FORECAST DISCUSSION
NWS SPRINGFIELD MO
615 PM CDT Thu Aug 8 2013
.SHORT TERM...(This Evening through Friday)
ISSUED AT 216 PM CDT THU AUG 8 2013
As with the past few nights, the main concern will be where the
low level baroclinic zone for possible heavy or excessive rainfall
sets up tonight. The effective sfc boundary has set up just north
of the MO/AR border and far ne OK. A mix of the 12Z ECMWF and
higher res models looks good for a start as far as the current
picture is concerned. The GFS seems to be suffering from poor
initialization over the Plains and really blows up convection (it
should be raining now), and the NAM seems to have the sfc front a
little too far south.
Overall, will see a low level 925/850mb southerly flow will again
become established over the southern plains and veer with time
allowing convection to break out from west-east into the Ozarks
this evening and overnight. WPC guidance was primarily used for
the gridded forecast which has the highest axis of precip from the
Joplin area east along Highway 60 over southern MO. The heaviest
rain is tied to the best low level 925-850mb layer convergence
along the edge of higher instability/moisture/theta-e
pooling/convergence. With PWATs still in the neighborhood of two
inches, any training storms will have the potential to produce
localized excessive rain and serious flooding.
Like the past few days, we have had a tough time destabilizing with
daytime cloud cover. Can`t rule out an isolated stronger storm
this afternoon, or this evening and tonight as convection first
moves in over far sw mo where stronger instability will reside. A
low end severe weather threat exists.
Rainfall will linger into Friday morning. As with the past few
days, it looks as through heavier rains will be ongoing but
winding down in the morning.
.LONG TERM...(Friday Night through Thursday)
ISSUED AT 216 PM CDT THU AUG 8 2013
For Friday night the story is more or less the same. Guidance-wise,
there isn`t any clear favorite. A basic guidance consensus keeps
the low level baroclinic zone fairly far to the south, closer to
the AR/MO line and points just to the south. The NAM is farther
north with heavier rain into southern MO. Will keep a heavier rain
axis higher pops again over far southern MO along and south of MO
Hwy 60.
Early next week, it still looks like with a bit more
amplification in the mid level flow over the western and central
conus, more of nw flow pattern will set up with chances for
convective cluster(s) to move southeast from the central Plains
into the Ozarks along the reoriented nw-se oriented frontal zone.
Not a lot of confidence in the timing of rainfall, but it does
look like we will have at at least a couple shots of additional
storms over or nearby the cwa. Toward midweek, the building upper
ridge shifts a bit farther east with strengthening sfc high
pressure over the Great lakes and Midwest with better chance for
dry weather toward the Wed/Thu period.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday Evening)
ISSUED AT 555 PM CDT THU AUG 8 2013
A few cells have developed east of the forecast points so far
early this evening, but we are expecting the main development to
occur later this evening into the overnight. Current HRRR and
local-WRF models suggesting the time period after 07-08z for
development first along the Missouri/Arkansas border and then
shifting northward into SGF/JLN terminal locations. Expecting
MVFR/IFR conditions within the thunderstorms and generally VFR
outside of the thunderstorms.
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...FLASH FLOOD WATCH through Saturday afternoon FOR MOZ055>058-
066>071-077>083-088>098-101>106.
KS...FLASH FLOOD WATCH through Saturday afternoon FOR KSZ073-097-101.
&&
$$
SHORT TERM...DSA
LONG TERM...DSA
AVIATION...Lindenberg
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1143 PM CDT Tue Aug 6 2013
.UPDATE...
Issued at 945 PM CDT TUE AUG 6 2013
Have made some minor changes to PoPs to account for trends with
convection across northern Missouri and convection over southern
Kansas possibly moving in later tonight. Also, confidence is
increasing that we`ll see thunderstorms develop between 10pm and
midnight in our far southern zones. ACCAS was evident on visible
imagery before sunset and on IR imagery before the cirrus shield from
the Kansas storms obscured things. Still, an arc of ACCAS can be
inferred from southern Missouri to around Harrisonville. The HRRR,
our local WRF and the RAP all generate storms in this arc within the
next few hours. Across our north, thunderstorms have developed ahead
of the main front, possible on or near a residual outflow boundary.
Instability will remain moderate to strong overnight and shear may be
enough for some storm organization. But updrafts have had a hard time
persisting for very long to utilize the shear. Overall, the initial
updrafts are more likely to produce marginally severe hail tonight.
Otherwise the greatest threat should be from heavy rain and localized,
especially if storms in our south develop and track over areas that
saw rain late last night/early this morning. Localized strong to
damaging winds may also continue into the night with any of the
strongest storms.
&&
.SHORT TERM...(This Evening through Wednesday Night)
Issued at 331 PM CDT TUE AUG 6 2013
Tonight: Another potentially active period is anticipated late this
evening into the overnight hours for much of the forecast area.
Several boundaries are noted across the region as of early this
afternoon, all that may potentially contribute as a focus for
convective development during the next 12 hours. An outflow boundary
from earlier convection over Nebraska and Iowa, identified by
surface observations and transient convective towers, has pushed
southward into northern Missouri, approximately 70 miles north of
the Interstate 70 corridor. Second, a poorly defined thermal
boundary that has been a primary driving force for several days
remains across southeast Kansas into southern Missouri. Lastly, a
cold front over the Nebraska Panhandle into southeast South Dakota
continues a steady southward push. These boundaries will be the main
focus for additional showers and thunderstorm development across the
forecast area this evening and overnight. Upslope flow over the High
Plains will once again help promote scattered thunderstorms over
western Kansas this afternoon. This activity will likely evolve into
a complex of thunderstorms and move eastward during the evening.
While the initial activity may gradually weaken, a strengthening
30kt low-level jet will induce additional convection along and north
of the aforementioned boundaries across the CWA. This overall
philosophy is supported by recent convective-resolving and
operational models, and is similar to last nights evolution.
Additional thunderstorms may develop along the cold front over
Nebraska and Iowa, with a complex of thunderstorms moving towards
northern Missouri. Models have struggled with consistently
developing activity in this region, and the lack of a cumulus field
along the boundary remains. Nevertheless, sufficient forcing should
allow for thunderstorms to develop in this region, but uncertainty
remains to how far south the activity will persist. Overall,
uncertainty exists with current forecast with regards to timing and
coverage for tonight, but enough evidence supports scattered to
occasionally widespread convection over portions of the CWA
overnight. With high precipitable water values and moderate
instability, the most robust convection will be capable of heavy
rainfall and localized damaging wind gusts. While widespread
flooding concerns are not expected at this stage, localized flooding
in some creeks or streams cannot be ruled out.
Wednesday/Wednesday night: The majority of moderate/heavy rainfall
should be in the process of exiting the CWA around sunrise Wed. The
cold front will push through the forecast area no later than
mid-morning Wednesday, with northerly winds occurring behind the
boundary. Some drier air will advect into the northern portion of
the CWA by Wed evening, while a humid airmass should remain
elsewhere. Scattered showers or weak thunderstorms will be possible
north of the frontal boundary during the daylight hours, mainly
south of Interstate 70. A much more substantial chance for rainfall
is expected Wednesday night into Thursday morning, mainly for areas
along and south of Interstate 70. Here, embedded waves within the
upper low and increasing isentropic ascent should lead to
widespread convective development. Areas of heavy rainfall will be
possible, and depending on tonights convective episode, concern may
increase for flooding late Wed night into Thursday as grounds become
saturated. More specifics will be realized in subsequent forecasts
as details on frontal position, wave timing, and previous convective
evolution becomes known.
.LONG TERM...(Thursday through Tuesday)
Issued at 331 PM CDT TUE AUG 6 2013
Long term forecast will remain focused on surface boundary across
the region and numerous short wave troughs moving through the flow
providing a chance for precipitation through much of the period. Hudson
Bay low will begin to quickly translate eastward across the northern
Great Lakes region as a shortwave trough rounds the southern edge of
a newly developing region of low pressure in this same area. General
northwest flow pattern across the central US will quickly begin to
break down as a region of low pressure moves out of Baja California
and into the Four Corners region. The trough will continue to move
eastward across the Rockies and out onto the Plains by the end of
the week. As this system nears the region...it will interact with a
quasi-stationary surface boundary that will be positioned across the
Central Plains. Depending on where this boundary eventually
positions itself will decide where main convective activity will
likely develop. Current long-range models indicate that there is the
potential for storms to redevelop over the same general region
through much of the period. With precipitable water values progged
to be 1.5 to 2 inches across many areas, expect heavy rain to
develop leading to potential flooding issues in these locations.
By early next week, models begin to diverge with the EC rebuilding a
ridge over the Rockies and keeping more of a pronounced northwest
flow component while the GFS develops a broader ridge with more of a
zonal component to the flow over the CWA. Both models bring numerous
shortwave troughs across the region, but timing of these features
remain uncertain and will effect precipitation chances.
&&
.AVIATION...(For the 06Z TAFS through 06Z Wednesday Night)
Issued at 1144 PM CDT TUE AUG 6 2013
Models continue to indicate an area of thunderstorms over south
central Kansas will move to the east through the night with an arc of
thunderstorms developing from southern Missouri to the south side of
the Kansas City metro. Latest radar returns show storms developing in
the vicinity of the Lake of the Ozarks, near to where an ACCAS field
has been evident all night. This should eventually arc back to the
west and impact the south KC metro. Have maintained VCTS in the TAFs
because for now, the greatest probabilities for storms appear to the
south of the terminals. However some storms may venture further north
but confidence is higher that greater impacts will be felt south of
the terminals.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
UPDATE...CDB
SHORT TERM...Blair
LONG TERM...PMM
AVIATION...CDB
AREA FORECAST DISCUSSION
NWS GLASGOW MT
1018 PM MDT TUE AUG 6 2013
.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH THURSDAY...
UPDATE...A FRONT CONTINUES TO SPLIT THE REGION IN TWO PARTS. NORTH
OF THE FRONT THUNDERSTORMS DEVELOPED THIS AFTERNOON AND HAVE SINCE
PUSHED INTO NORTH DAKOTA. LOOKING FOR A FAIRLY QUIET REMAINDER OF
THE EVENING. UPDATED FORECAST TO REFLECT THE DOWNWARD TREND IN THE
COVERAGE OF THE CONVECTIVE SHOWERS AND THUNDERSTORMS FOR THE NIGHT
TIME HOURS. PROTON
NORTHWESTERLY FLOW ALOFT CONTINUES THROUGH THURSDAY. WEATHER FOR
THE NORTHERN CONUS IS DOMINATED BY A LARGE UPPER LOW OVER NORTH
CENTRAL CANADA. AS THIS LOW SPINS AND MAKES SLOW PROGRESS
EASTWARD OVER THE NEXT FEW DAYS...PERIODIC SHORTWAVE DISTURBANCES IN
THE FLOW AROUND THE LOW PASS OVER THE MONTANA AREA. THESE
DISTURBANCES BRING SUPPORT FOR SHOWERS AND THUNDERSTORMS. SHOWER
ACTIVITY MOSTLY OCCURS IN THE AFTERNOONS AS DAYTIME HEATING OF THE
RELATIVELY MOIST BOUNDARY LAYER CREATES CONVECTIVE INSTABILITY
WHICH COMBINES WITH MODEST UPPER LEVEL FORCING FROM SHORTWAVE
ACTIVITY.
CURRENTLY..SOME NON-SEVERE SHOWER AND THUNDERSTORM ACTIVITY IS
EXPECTED WITH THE PASSAGE OF A SHORTWAVE TONIGHT WITH A WEAKER ONE DUE
LATE WEDNESDAY. THURSDAY AFTERNOON HAS A LOWER CHANCE OF
CONVECTIVE ACTIVITY AS THE GFS AND NAM HAVE THE CANADA LOW BY
THAT TIME FAR ENOUGH EASTWARD TO ALLOW SOME BUILDING OF HIGH
PRESSURE OVER THE ROCKIES.
FOR TONIGHT...THE HRRR MODEL SEEMS TO HAVE A REASONABLE HANDLE ON
DEVELOPMENT FOLLOWING THE LOWER RESOLUTION MODELS IN PRODUCING AN
AREA OF SHOWERS OVER THE NORTHEAST 2/3RDS OF THE CWA...WHICH DIES OUT
AROUND 9PM. STRENGTH OF CONVECTION IS EXPECTED TO BE
MODEST...THOUGH SOME THUNDERSTORMS WILL OCCUR...AS BOUNDARY LAYER
INSTABILITY IS WEAK WITH LESS THAN 1000 J/KG OF MLCAPE AT
MOST...WHICH RAPIDLY DECLINES AFTER 6PM AS THE SURFACE COOLS
DIURNALLY.
TEMPERATURES ARE EXPECTED TO BE MILD THROUGH THURSDAY DUE TO CLOUD
COVER AND LIMITED THICKNESSES IN THE SOUTHWEST QUADRANT OF THE
CANADA LOW. THERE IS ALSO A LACK OF WELL-DEFINED SURFACE FEATURES
THAT WOULD LEAD TO STRONG WINDS. CURRENT SURFACE LOW EXITING THE
DAKOTAS HAS KEPT NORTHWESTERLY SURFACE WINDS IN PLACE. THESE WINDS
WILL BECOME LIGHTER TONIGHT AND WEDNESDAY...AND THEN MORE EASTERLY
ON THURSDAY AS A THERMAL SURFACE LOW DEVELOPS OVER THE ROCKIES. MARTIN
.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY...
THE EXTENDED PERIOD BEGINS THURSDAY NIGHT WITH HIGH PRESSURE AND A
HEAT DOME OVER THE SOUTHWESTERN DESERT...WITH AN UPPER RIDGE
EXTENDING NORTH ALL THE WAY UP INTO THE PACIFIC NORTHWEST. THE
CLOSED UPPER LEVEL CANADIAN LOW WILL BE RETREATING EAST INTO
ONTARIO...LEAVING BEHIND IN ITS WAKE ANOTHER...BUT WEAKER...TROUGH
OVER THE PRAIRIE PROVINCES. THIS PATTERN WILL MAINTAIN OUR
NORTHWEST FLOW ALOFT AND THE STATIONARY BOUNDARY ACROSS NORTHEAST
MONTANA THROUGH MOST OF THE WEEKEND. THIS FLOW WILL NOT BE
CLEAN...RESULTING IN OCCASIONAL SHORT PERIODS OF RAIN SHOWERS OR
THUNDERSTORMS. THEN AS THE RIDGE ATTEMPTS TO MOVE EAST A COUPLE OF
LOWS IN THE PAC-NW AND WESTERN CANADA SEND MOISTURE OVER THE
DIVIDE. THIS MOISTURE AND MORE DISTURBANCES WILL TEND TO KNOCK
DOWN THE RIDGE AND CONTINUE TO PRODUCE RAIN SHOWERS AND
THUNDERSTORMS INTO NEXT WEEK. GUIDANCE SUGGEST WARMING TO ABOVE
NORMAL...BUT THE PATTERN MIGHT RESIST THAT GUIDANCE TREND. FEW
SIGNIFICANT CHANGES WERE NEEDED. SCT
PREVIOUS DISCUSSION...
FORECAST THROUGH THE END OF THE WEEK WILL BE INFLUENCED BY THE
LINGERING EFFECTS OF THE STRONG HUDSON BAY LOW. UPPER RIDGE
BUILDING NORTH ALONG THE ROCKIES WILL BE THE MAIN PLAYER FOR EARLY
NEXT WEEK.
MODELS SLIPPING OUT OF AGREEMENT REGARDING THE HUDSON BAY LOW
AFTER IT DROPS INTO CENTRAL MANITOBA. ECMWF MOVES IT EAST FASTER
THEN THE GFS BUT LEAVES A PORTION BEHIND IN SASKATCHEWAN THURSDAY
NIGHT. EC CURRENTLY NOT INDICATING MUCH INFLUENCE ON THE SENSIBLE
WEATHER WITH THIS FEATURE BUT THAT COULD CHANGE. NORTHWEST FLOW
INTO EASTERN MONTANA ALONG WITH CANADIAN HIGH PUSHING INTO THE
NORTHERN PLAINS SUGGEST A SHORT PERIOD OF DRIER WEATHER BUT AS
SHORTWAVES BEGIN EJECTING OUT OF THE TROF ALONG THE WEST COAST AND
THROUGH THE NORTHERN ROCKIES RIDGE...WILL SEE A RETURN OF
THUNDERSTORM CHANCES.
AFTER A COOL START TO THE EXTENDED PERIOD WITH THE PROXIMITY OF
THE HUDSON BAY LOW...TEMPERATURES WILL WARM THROUGH THE WEEKEND
AS UPPER RIDGE PUSHES OUT INTO THE NORTHERN PLAINS. EBERT
&&
.AVIATION...
VFR TO MVFR CEILINGS DURING THE MORNING.
WITH THE PASSAGE OF THUNDERSTORMS EARLIER THIS EVENING EXCESSIVE
MOISTURE APPEARS TO BE ADEQUATE ENOUGH TO GENERATE A LOW CEILING
ACROSS THE NORTHERN AND EASTERN MOST TERMINALS WITH KOLF VERY
LIKELY TO SEE FUEL LOADING CONDITIONS. THE OTHER THREE TERMINALS
ARE CLOSE TO MVFR AND COULD ALSO EXPERIENCE THESE CONDITIONS BUT
ARE NOT YET PLACED INTO THE TAFS. WILL HAVE TO MONITOR THE GOES
FOG/IR SATELLITE PRODUCT ACROSS THE REGION THIS EVENING AND AMEND
AS NEEDED.
AN UPPER LEVEL RIDGE WEST OF THE DIVIDE AND A STRONG LOW PRESSURE
SYSTEM OVER MANITOBA WILL MAINTAIN NORTHWEST FLOW ALOFT FOR
NORTHEAST MONTANA. THESE WEATHER SYSTEMS HAVE PLACED A STATIONARY
FRONT ACROSS ROUGHLY THE LOCAL TERMINALS THAT WILL BE THE FOCUS OF
INTERMITTENT RAIN SHOWERS AND GENERAL THUNDERSTORMS WEDNESDAY
AFTERNOON AND EVENING. BRIEF PERIODS OF LESS THAN VFR CONDITIONS
ARE POSSIBLE WITH ANY THUNDERSTORMS THAT DEVELOP. ISOLATED FOG AND
LOW STRATUS IN THE EVENINGS COULD ALSO BE POSSIBLE AS A BY
PRODUCT BUT CONFIDENCE IS NOT YET HIGH ENOUGH TO PLACE IN THE
TAFS.
WIND WILL BECOME LIGHT AND VARIABLE TONIGHT INTO WEDNESDAY
EVENING. GAH
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
618 PM CDT THU AUG 8 2013
.AVIATION...00Z TAFS FOR KOFK...KLNK AND KOMA.
VFR CONDITIONS ARE EXPECTED FOR MOST OF THE TAF PERIOD. ISOLATED
SHOWERS NEAR ALL TAF SITES WILL GRADUALLY DIMINISH THROUGH THE
LATE EVENING...LEAVING MAINLY SCATTERED TO BROKEN MID LEVEL
CLOUDS. MORE CLEARING IN THE KOFK AREA WILL ALLOW MVFR FOG TO FORM
NEAR 12Z...BUT SHOULD ONLY LAST A FEW HOURS. OTHERWISE LIGHT AND
VARIABLE WINDS OVERNIGHT WILL BECOME NORTHEAST AT UNDER 10KT
BEFORE 18Z FRIDAY.
DERGAN
&&
.PREV DISCUSSION... /ISSUED 342 PM CDT THU AUG 8 2013/
DISCUSSION...
MAIN SHORT TERM CONCERN IS POPS THROUGH TONIGHT AS SCATTERED
SHOWERS CONTINUE TO DRIFT EAST ACROSS THE CWA.
LATEST WATER VAPOR IMAGERY AND LATEST RAP 500MB ANALYSIS SHOW A
LARGE UPPER LOW OVER ONTARIO WITH A RIDGE EXTENDING FROM THE FOUR
CORNERS REGION INTO BRITISH COLUMBIA. IN BETWEEN THIS...A WEAK
SHORTWAVE EXTENDS FROM EASTERN NEBRASKA INTO NORTHEAST KANSAS WITH
ANOTHER CIRCULATION IN SOUTH CENTRAL COLORADO.
THE SHORTWAVE ENERGY OVER THE REGION CONTINUES TO SUPPORT AN AREA
OF WIDELY SCATTERED SHOWERS OVER THE FORECAST AREA. THE LATEST RAP
SEEMS TO HAVE A GOOD HANDLE...ALBEIT A BIT OVERDONE ON QPF...AND
HAVE FOLLOWED MORE CLOSELY TO ITS TRENDS. UPPER LEVEL SUPPORT WILL
MOVE OUT OF THE AREA EARLY THIS EVENING SO HAVE ONLY CARRIED A
MENTION OF PCPN THROUGH THIS TIME. DID CONTINUE A MENTION OF SMALL
POPS IN THE FAR SOUTHEAST AFTER 06Z WITH SOME WEAK UPPER LEVEL
SUPPORT REMAINING INTO THE MORNING.
FRIDAY CONTINUES TO LOOK MOSTLY DRY BUT DID KEEP A SMALL POP IN
FOR THE SOUTH WITH SOME WEAK UPPER LEVEL SUPPORT IN THE AREA.
WITH MID/UPPER LEVEL FLOW OUT OF THE NORTHWEST THROUGH THE
WEEKEND...AND INCREASING WAA REGIME...WILL KEEP SOME SCATTERED
POPS ACROSS THE AREA...MAINLY IN THE NORTH. A STRONGER SHORTWAVE
WILL SLIDE ACROSS SOUTH DAKOTA THROUGH THE NORTHWEST FLOW
SATURDAY...SO BEST CHANCES WILL BE IN THE NORTH...ALTHOUGH WE
SHOULD NOTE THAT THE NEW 12Z ECMWF IS TRENDING THIS WAVE A BIT
FARTHER SOUTH.
ON AND OFF AGAIN SHOWERS AND TSTMS CANNOT BE RULED OUT THROUGH THE
EXTENDED WITH WEAK UPPER LEVEL SUPPORT SLIDING THROUGH THE REGION.
KERN
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1228 AM CDT WED AUG 7 2013
.SYNOPSIS...
A STRONG COLD FRONT WILL MOVE THROUGH TONIGHT SPARKING
TSTMS...SOME SEVERE. A SUBTROPICAL DISTURBANCE...CURRENTLY ACROSS
AZ...UT AND WRN COLO WILL LIFT THROUGH THE SRN PTN OF FCST AREA
WEDNESDAY AND THURSDAY PRODUCING RAIN...MAINLY SOUTH OF THE
INTERSTATE 80. THE UPPER LEVEL LOW ACROSS HUDSON BAY WILL MIGRATE
INTO THE CANADIAN MARITIMES THIS WEEKEND. IN DOING SO...A LOBE OF
UPPER LEVEL ENERGY COULD PRODUCE THUNDERSTORMS ACROSS NRN NEB
SATURDAY NIGHT AND SUNDAY.
&&
.UPDATE...
ISSUED AT 754 PM CDT TUE AUG 6 2013
GIVEN THAT THE HRRR MODEL IS PLUGGING SWRN NEB WITH A SQUALL LINE
THIS EVENING AND THAT WFO CYS IS ISSUING WARNINGS FOR THE
PANHANDLE...POPS HAVE BEEN RAISED TO AROUND 50 PERCENT AND SEVERE
WORDING HAS BEEN ADDED UNTIL MIDNIGHT. THE 23Z HRRR CONTINUES TO
FLOG SWRN NEB WITH STRONG TO PERHAPS SEVERE STORMS. THE CONVECTIVE
COMPLEX SHOULD EXIT THE FCST AREA BY AROUND 05Z THIS EVENING.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 335 PM CDT TUE AUG 6 2013
TONIGHT AND WEDNESDAY...CONDITIONS FAIRLY UNSTABLE ACROSS
SOUTHWEST INTO CENTRAL NEBRASKA...AND SCATTERED THUNDERSTORMS ARE
STILL POSSIBLE. A COLD FRONT IS CURRENTLY MOVING SOUTH INTO
NORTHERN NEBRASKA...WITH AN OLD OUTFLOW BOUNDARY NEARLY STATIONARY
ACROSS SOUTHWEST NEBRASKA. THESE FEATURES COULD SERVE AS A FOCUS
FOR THUNDERSTORM INITIATION YET THIS AFTERNOON. OTHER STORMS
DEVELOPING ACROSS EASTERN WYOMING ARE EXPECTED TO MOVE EAST AND
SOUTHEAST AND MAY MOVE INTO SOUTHWEST NEBRASKA LATER THIS EVENING.
COVERAGE OF ANY STORM ACTIVITY IS EXPECTED TO REMAIN WIDELY
SCATTERED AS OVERALL FORCING IS FAIRLY WEAK...AND NO REAL DEFINED
UPPER LEVEL DISTURBANCE IS PRESENT. WILL KEEP POPS AT 30 PERCENT
OR LESS TONIGHT DUE TO THESE FACTORS.
A SUB TROPICAL DISTURBANCE WILL APPROACH THE AREA FROM THE SOUTHWEST
CONUS WEDNESDAY...BUT CURRENT INDICATIONS ARE THAT THE MORE
SIGNIFICANT RAIN FROM THIS SYSTEM WILL REMAIN TO OUR SOUTH AND WEST
DURING THE DAY WEDNESDAY. COOLER CONDITIONS ARE EXPECTED FOR
WEDNESDAY IN THE WAKE OF THE COLD FRONT AND WITH THE INCREASED CLOUD
COVER FROM THE SUB TROPICAL DISTURBANCE.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 335 PM CDT TUE AUG 6 2013
WEDNESDAY NIGHT THROUGH FRIDAY...
ALL EYES ARE ON THE SUBTROPICAL DISTURBANCE CURRENTLY ACROSS AZ/SRN
UT/SWRN COLO. THE MODEL CONSENSUS TAKES THIS DISTURBANCE THROUGH
NERN COLO/SWRN NEB/NWRN KS WEDNESDAY NIGHT AND THURSDAY. A CLOSED
700MB LOW FORMS BRIEFLY WEDNESDAY NIGHT AND THEN OPENS UP IN A
POSITIVE FASHION THURSDAY. THUS IT WOULD APPEAR MOST OF THE RAIN
WILL FALL ON THE FORWARD SIDE OF THE DISTURBANCE WEDNESDAY NIGHT AND
THURSDAY. THE HPC...GEM...GFS...NAM AND ECM FCSTS WERE BLENDED FOR
THE QPF FORECAST WHICH PRODUCES 1/2 TO 1 INCH OF RAIN ALONG AND
SOUTH OF INTERSTATE 80. POPS ARE STILL LIMITED TO 40 PERCENT
GIVEN THE TIMING AND TRACK UNCERTAINTIES OF A SYSTEM ROTATING
NORTH AND EAST AROUND A SUBTROPICAL HIGH.
THE MODELS DO SHOW A COLD FRONT APPROACHING NCNTL NEB LATE THURSDAY
AFTN WHICH COULD ADD FOCUS TO THE RAIN EVENT. K-INDICES ARE
OPERATING IN THE 30-35C RANGE. THE MODELS SHOW SOME CLEARING
THURSDAY AFTN WHICH WOULD ALLOW TEMPS TO RISE INTO THE 70S.
FOR FRIDAY...THE NAM...ECM AND GEM SHOW SOME AFTN TSTM ACTIVITY
DEVELOPING OFF THE LARAMIE RANGE WHICH COULD DRIFT INTO WRN NEB LATE
IN THE AFTERNOON. TEMPERATURES SHOULD RISE INTO THE UPPER 70S TO
LOWER 80S. OTHERWISE FRIDAYS FORECAST IS UNEVENTFUL. THE NAM SHOWED
STORMS FIRING OFF THE THE BACK HILLS THURSDAY AS THE COLD MOVES
THROUGH. THESE STORMS...IF THEY DEVELOP...WOULD MOVE SOUTHEAST INTO
NCNTL NEB LATE IN THE AFTN.
FRIDAY NIGHT THROUGH TUESDAY...RAIN CHANCES PERK UP SATURDAY NIGHT
AND SUNDAY AS A REINFORCING COLD FRONT DROPS THROUGH THE NRN PLAINS AND
INTO NCNTL NEB. THE GEM...GFS AND ECM ARE IN GOOD AGREEMENT TAKING A
LOBE OF ENERGY THRU THE NRN PLAINS AS THE HUDSON BAY LOW KICKS OUT
INTO THE CANADIAN MARITIMES. MOST OF THIS ENERGY AND RAINFALL TRACK
THROUGH SD SO JUST NRN NEB PICKS UP A 1/4 INCH OR SO RAINFALL.
THE REST OF THE FCST IS JUST ISOLATED POPS. THE 300MB JET MAX SWINGS
EAST FOCUSING THE BEST SUPPORT FOR RAINFALL INTO THE OHIO VALLEY.
FARTHER WEST...A BELT OF STRONG WINDS ALOFT WILL CONTINUE ACROSS KS
AND COLO. THIS COULD SUPPORT ISOLATED DIURNALLY DRIVEN TSTMS
ACROSS WRN/NCNTL NEB. IT LOOKS LIKE THE SUBTROPICAL HIGH SHIFTS EAST
INTO TEXAS A BIT AND TAKES THE BEST MOISTURE THRU THE MID SOUTH.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1230 AM CDT WED AUG 7 2013
ONGOING CONVECTION ACROSS SOUTHWESTERN NEBRASKA...MAY IMPACT THE
KLBF TERMINAL VICINITY OVER THE NEXT COUPLE OF HOURS. ATTM...THIS
ACTIVITY IS EXPECTED TO REMAIN JUST OFF TO THE SOUTHWEST OF THE
KLBF TERMINAL. FOR THE REMAINDER OF TONIGHT AND WEDNESDAY...EXPECT
SCATTERED TO BROKEN CLOUDINESS ACROSS WESTERN AND SOUTHWESTERN
NEBRASKA WITH CIGS GENERALLY RANGING FROM 10000 TO 25000 FT AGL.
FOR THE KVTN TERMINAL...SCATTERED TO BROKEN CIGS OF 25000 FT AGL
ARE EXPECTED OVER THE NEXT 24 HRS.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...CDC
SYNOPSIS...CDC
SHORT TERM...TAYLOR
LONG TERM...CDC
AVIATION...CLB
AREA FORECAST DISCUSSION
NWS BUFFALO NY
609 PM EDT WED AUG 7 2013
.SYNOPSIS...
SOUTHERLY WINDS BETWEEN HIGH PRESSURE OFF THE EAST COAST AND A COLD
FRONT APPROACHING FROM THE MIDWEST WILL KEEP WARM AND MORE HUMID
CONDITIONS TO OUR AREA TONIGHT...ALONG WITH A CHANCE FOR A FEW
SHOWERS AND THUNDERSTORMS. SHOWERS AND THUNDERSTORMS WILL BECOME
MORE WIDESPREAD LATER TONIGHT AND THURSDAY MORNING AS THE FRONT MOVES
ACROSS WESTERN AND CENTRAL NEW YORK. SOMEWHAT UNSETTLED WEATHER WILL
LAST INTO FRIDAY.
&&
.NEAR TERM /THROUGH THURSDAY/...
ONGOING CONVECTION WILL MAKE THIS EVENINGS FORECAST A FAST
EVOLVING ONE...AS SEVERAL AREAS OF THUNDERSTORMS CAN BE SEEN ON
RADAR LATE THIS AFTERNOON. THE MOST SIGNIFICANT CLUSTER IS TO OUR
SOUTH...WITH A SCATTERED LINE EXTENDING FROM ROCHESTER TO THE
SAINT LAWRENCE...AND ANOTHER LINE EXTENDING FROM SE MICHIGAN INTO
SOUTHERN ONTARIO NORTH OF LAKE ONTARIO. THE MAJORITY OF THIS
ACTIVITY IS NOT ACROSS WESTERN NEW YORK...DESPITE FAIRLY UNSTABLE
AIR IN PLACE OF AROUND 1000 J/KG.
BASED ON RADAR TRENDS AND THE SCATTERED ACTIVITY ACROSS WESTERN
MICHIGAN...AND CLEARING UPSTREAM ON VISIBLE SATELLITE...EXPECT
ONLY SCATTERED CONVECTION DURING THE EVENING HOURS. THIS IS
SUPPORTED BY THE 18Z NAM AND MOST HRRR RUNS...AND WHILE SOME OTHER
GUIDANCE CARRIES SIGNIFICANT QPF THIS EVENING...MUCH OF THIS IS
ADVECTING AREAS OF CONVECTION WHICH HAVE NOT DEVELOPED AS FORECAST.
LATER TONIGHT MAY BE A DIFFERENT STORY...AS THE SHOWERS AND
THUNDERSTORMS ACROSS ONTARIO ARE FORECASTS TO DROP ACROSS OUR
REGION AS THE FRONTAL BOUNDARY SAGS SOUTH. THIS WILL LIKELY BRING
SHOWERS AND THUNDERSTORMS TO MOST LOCATIONS TONIGHT...MAINLY IN THE
11 PM TO 4 AM TIMEFRAME. GIVEN WIND FIELDS AND LINGERING
INSTABILITY...THERE WOULD BE A MARGINAL OPPORTUNITY FOR SEVERE
WEATHER WITH THIS...BUT PROBABLY CONTINGENT ON STRONG STORMS
DEVELOPING UPSTREAM AND ADVECTING INTO OUR REGION. THIS SCENARIO
WOULD GIVE US OPPORTUNITY TO ADJUST...AND GIVEN THE MARGINAL
PROBABILITY WILL NOT CARRY ANY ENHANCED WORDING AT THIS TIME.
WITH THE CONTINUED INFLUX OF WARM AND HUMID AIR THROUGH THE
NIGHT...THE OVERNIGHT LOWS WILL BE IN THE MIDDLE TO UPPER 60S AND
EVEN NEAR 70 IN DOWNSLOPING AREAS ACROSS THE LAKE PLAINS AND IN
URBAN AREAS. WITH THE SLOW PASSAGE OF THE COL FRONT ON
THURSDAY...EXPECT HIGH TEMPS TO REACH THE UPPER 70S TO LOWER 80S.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
MATURE SURFACE LOW PRESSURE AND PARENT UPPER LEVEL LOW WILL BE
CENTERED OVER NORTHERN ONTARIO PROVINCE NEAR THE HUDSON BAY THURSDAY
EVENING. A COLD FRONT ORIENTED FROM A TRIPLE POINT LOW OVER THE
CANADIAN MARITIMES SOUTHWEST ACROSS THE ADIRONDACKS TO THE OHIO VALLEY
WILL BE STALLING/SLOWING AS IT BECOMES PARALLEL WITH THE UPPER LEVEL
FLOW. A SURFACE WAVE WILL LIFT NORTHEAST ALONG THE FRONT THURSDAY
EVENING. A SWATH OF SHOWERS ASSOCIATED WITH THIS WAVE AND POSSIBLY
SOME EMBEDDED LIGHTING LOOKS TO SHIFT ACROSS THE SOUTHERN TIER INTO
THE FINGER LAKES AND ACROSS CENTRAL NEW YORK IN THE EVENING. ITS
NORTHERN EDGE MAY EVEN BRING SOME LIGHT RAIN TO THE NIAGARA
FRONTIER. THE SHOWERS WILL SHIFT EAST INTO CENTRAL AND EASTERN
NEW YORK OVERNIGHT.
THE SURFACE WAVE WILL SHIFT NORTH ACROSS NEW ENGLAND THROUGH FRIDAY
WHILE ACTING TO SHOVE THE COLD FRONT WELL SOUTH AND EAST OF THE
FORECAST AREA. A CHANCE OF RAIN WILL LINGER ACROSS THE FINGER LAKES
AND NORTH COUNTY FRIDAY MORNING OTHERWISE EXPECT WESTERN AND NORTH
CENTRAL NEW YORK TO BE RAIN FREE BY MID-AFTERNOON BEHIND THE FRONT.
THE 12Z NAM IS THE ONLY OUTLIER IN THIS SCENARIO AS IT FORECASTS A
SECOND SURFACE WAVE TO LIFT ALONG THE FRONT EARLY FRIDAY WITH
ANOTHER ROUND OF RAIN ACROSS WNY THROUGH THE AFTERNOON. THIS IDEA HAS
BEEN DISCOUNTED WITH THE MAJORITY OF FORECAST MODELS SHOWING DRY
CONDITIONS ON FRIDAY. CANADIAN PRAIRIE SOURCED HIGH PRESSURE WILL
BUILD ACROSS THE GREAT LAKES REGION THROUGH FRIDAY AND INTO SATURDAY
WITH SEASONABLY COOL TEMPERATURES AND DRY SUNNY CONDITIONS TO START
OFF THE WEEKEND.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AN AMPLIFIED WESTERN RIDGE AND EASTERN TROUGH 500MB PATTERN WILL BE IN
PLACE ACROSS SOUTHERN CANADA OVER THE WEEKEND. ZONAL FLOW IN THE
BASE OF THE EASTERN CANADIAN TROUGH WILL EXTENDING FROM THE NORTHERN
PLAINS EAST ACROSS THE GREAT LAKES TO THE NORTHEAST STATES. THIS
SHOULD KEEP SEASONABLY COOL AND DRY WEATHER IN PLACE FOR AT LEAST
SUNDAY AND MONDAY. MEDIUM RANGE MODELS THEN SHOW THE NEXT STRONG
VORTICITY MAX/DISTURBANCE TO DROP INTO THE BASE OF THIS TROUGH
ACROSS THE GREAT LAKES MONDAY NIGHT AND LIFTING INTO ATLANTIC CANADA
ON TUESDAY. THE 00Z ECMWF IS MUCH DRIER AHEAD OF THE TROUGH AXIS
THAN THE 12Z GFS SHOWING JUST A LIMITED SHOWER THREAT. THE GFS SHOWS
MORE OF A FRONTAL ORIENTATION.
HAVE ONLY INCLUDED A SLIGHT CHANCE OF SHOWERS FOR NOW MONDAY NIGHT
IN TO TUESDAY UNTIL MORE MODEL AGREEMENT CAN BE MADE. BY WEDNESDAY
HIGH PRESSURE EITHER LINGERS OR BUILDS BACK ACROSS NEW YORK DEPEND
ON WHICH MODEL YOU LOOK AT BUT WILL KEEP WEDNESDAY DRY. THE
LINGERING TROUGH OVER EASTERN CANADA WILL KEEP SEASONABLY COOL
TEMPERATURES IN PLACE ACROSS THE FORECAST AREA THROUGH MID NEXT WEEK
WITH NO STRONG CONNECTION TO THE GULF OR ATLANTIC.
&&
.AVIATION /22Z WEDNESDAY THROUGH MONDAY/...
AT 21Z...MOSTLY VFR CONDITIONS WERE IN PLACE...WITH THE MAIN
CONCERN THE POTENTIAL FOR CONVECTION. FOR THIS EVENING...THE BEST
CHANCE FOR THUNDERSTORMS WILL BE ROC EASTWARD. AFTER THIS...
EXPECT A WEAKENING LINE OF THUNDERSTORMS TO DROP ACROSS THE
REGION. THUNDERSTORMS COULD TEMPORARILY DROP VSBY TO 2 SM IN
HEAVY RAIN.
OUTSIDE OF THUNDERSTORMS...EXPECT MAINLY VFR CONDITIONS. LINGERING
LOW MOISTURE MAY RESULT IN SOME LOW CLOUDS OR FOG AT JHW...OR
BRIEF PERIODS OF MVFR CIGS ELSEWHERE. TAFS HEDGE ON THE OPTIMISTIC
SIDE...SINCE THERE IS STILL UNCERTAINTY AS TO WHERE RAIN WILL FALL
OVERNIGHT.
OUTLOOK...
THURSDAY...MAINLY VFR WITH A CHANCE OF SHOWERS AND THUNDERSTORMS.
FRIDAY...MAINLY VFR WITH A CHANCE OF SHOWERS AND THUNDERSTORMS.
SATURDAY AND SUNDAY...VFR.
MONDAY...VFR WITH CHANCE OF AFTERNOON SHOWERS AND THUNDERSTORMS.
&&
.MARINE...
AS A COLD FRONT CROSSES THE CENTRAL LAKES LATE TONIGHT AND EASTERN
LAKES ON THURSDAY...THE WINDS WILL SWITCH TO THE WEST SOUTHWEST AND
DIMINISH. HIGH PRESSURE IS FORECAST TO SETTLE ACROSS THE EASTERN
LAKES ON FRIDAY. SMALL CRAFT ADVISORY CONDITIONS ARE NOT EXPECTED.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...WCH
NEAR TERM...APFFEL/WCH
SHORT TERM...SMITH
LONG TERM...SMITH
AVIATION...APFFEL/WCH
MARINE...WCH
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
603 PM EDT WED AUG 7 2013
.SYNOPSIS...
RAIN AND THUNDER CHANCES INCREASE THIS EVENING, AS A COLD FRONT
MOVES SOUTHEAST TOWARDS THE AREA. THIS FEATURE WILL THEN STALL
WEST OF THE AREA BY MORNING, KEEPING THE THREAT FOR CONTINUED
SHOWERS AND STORMS IN THE FORECAST THROUGH THE REMAINDER OF THE
WORK WEEK. THIS FRONTAL PASSAGE LOOKS TO FINALLY OCCUR FRIDAY
EVENING.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
545 PM UPDATE...
WITH CLOUDY SKIES AND MARINE LAYER SHOWERS ARE NOT MATERIALIZING.
LOWERED POPS. A FEW SHOWERS AND TSTORMS FORMED IN WRN NY AND WRN
PA BUT THEY ARE DYING AS THEY MOVE EAST. BULK OF PA PRECIP WILL
MISS TO THE SOUTH AND VERY LITTLE IN NY. SEE NO REASON WHY THE
MARINE LAYER WITH COOL TEMPS WILL NOT REMAIN THROUGH THE NIGHT.
245 PM UPDATE...
SFC LOPRES JUST SOUTH OF HUDSON BAY HAS DRAPED A CDFNT DOWN ACRS LK
HURON AND SWWRD INTO NRN MO. AT THE SAME TIME CONVECTION THAT DVLPD
OVRNGT HAS THROWN OUT A GUST FRONT AND HAS ALLOWED STORMS TO DVLP
ACRS NRN OH. MAIN AREA OF STORMS ACRS SRN ONTARIO HAS LIFTED NORTH
AS EXPECTED WITH MAIN S/WV ROTATING ARND BASE OF HUDSON BAY TROF.
TIMING ON THIS AFOREMENTIONED LINE OF STORMS PLACES IT INTO EXTRM WRN
ZONES BY 21Z THIS AFTN AND WL WORK TWD CNTRL PART OF CWA BY 00Z.
THIS LOOKS TO BE KICKED OFF BY S/WV WORKING ITS WAY EAST ACRS NRN OH
AND IT APPEARS TO BE HEADING A LITTLE SOUTH OF EAST. THUS, WL
MAINTAIN LKLY POPS THRU TONIGHT WITH CONTINUAL MOISTURE BEING PUMPED
INTO REGION ON LLJ AND PW VALUES INCRSG TO NEAR 1.50 INCHES AND ANY
SUBTLE S/WVS THAT ENCROACH UPON THE AREA. BULLSEYE OF QPF ALONG THE
I-81 CORRIDOR ADVERTISED BY 12Z GFS AND LATEST RAP APPEARS TO BE A
RESULT OF CONVECTIVE FEEDBACK AND HV DISCOUNTED THIS SOLN. THINK
THAT AREAL AVGS WL LKLY BE BETWEEN 0.25 AND 0.50 INCHES.
AS FOR OVRNGT MINS DO NOT THINK TEMPS WL MV MUCH AS CLDS RMN
ENTRENCHED OVR AREA. FCST LOWS WL BOTTOM OUT IN THE L/M 60S.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/...
245 PM UPDATE...
FRONTAL BNDRY WL STALL OUT THUR MRNG JUST TO THE WEST OF THE AREA
AND RMN THERE INTO FRIDAY. VRY LITTLE MIXING WL OCCUR DRG THE DAY AS
AREA WL LKLY BE SOCKED IN WITH CLDS ONCE AGAIN. MAX TEMPS WL JUST
BARELY TOP OUT IN THE 80S. CAPES WL BE SIMILAR TO WED WITH VALUES
APPCHG 1000 J/KG BUT WIND SHEAR IS EXPECTED TO DROP OFF DRG THE DAY.
PW VALUES PROGGED TO APPCH 2.00 INCHES DRG THE DAY THUS ANY STORM
THAT DVLPS MAY PRODUCE MODERATE TO HVY RAIN.
LKLY POPS WL CONTINUE TOMORROW NGT AS BNDRY RMNS STALLED OUT TO THE
WEST. MED RANGE MODELS HINTING AT SFC LOPRES RIDING UP ALONG THE
FRONT THU NGT AND HELPING GIVE THE FRONT A LITTLE SHOVE TO THE
SOUTH.
FROPA NOW LOOKS TO OCCUR DRG THE DAY FRIDAY. THUS, HV TAKEN OUT PCPN
AFT 12Z SATURDAY. NO OTHER CHGS NEEDED TO THE END OF THE SHORT TERM
WITH PERHAPS SOME LINGERING SHOWERS ON FRIDAY WITH RMNG UL WV MVG
THRU BHND FRONT. ELONGATED VORT MAX PROGGED TO MV THRU ON SATURDAY
BUT WITH DRY AIRMASS IN PLACE NOT EXPECTING MUCH MORE THAN CLDS AT
THIS POINT.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
200 PM UPDATE...
AREA REMAINS UNDER A BROAD LONG WAVE UPPER LEVEL TROUGH THROUGH
THE PERIOD AND SLIGHTLY COOLER THAN NORMAL TEMPERATURES WITH HIGHS
IN LOWER TO MIDDLE 70S AND NIGHTTIME LOWS IN THE 50S.
A FRONT THAT MOVED THROUGH THE AREA EARLY SATURDAY IS FORECAST TO
STALL IN A EAST-WEST MANNER ACROSS VIRGINA SATURDAY NIGHT INTO SUNDAY.
FROM THIS POINT MODELS HAVE DIFFERENCES OF TIMING AND POSITIONING
OF WAVES MOVING EASTWARD ALONG THIS FRONT THROUGH MIDWEEK CAUSING
SOME UNCERTAINTY IN THE FORECAST.
FORECASTED CLOUDS TO SPREAD NORTH WITH A WAVE ON SUNDAY BUT JUST
PLACED A SLIGHT CHANCE THUNDERSTORMS IN THE POCONOS FOR SUNDAY
AFTERNOON. HIGH PRESSURE BUILDS ACROSS SUNDAY NIGHT BEHIND THIS
WAVE. A SHORT-WAVE MOVING AROUND THE UPR LEVEL LOW TO OUR NORTH
MAY BRING A SLIGHT CHANCE OF SHOWERS OR THUNDERSTORMS IN THE
AFTERNOON MONDAY.
UNCERTAINTY INCREASES TUESDAY AS GFS LINKS A SHORT-WAVE MOVING
AROUND THE UPR LOW TO THE NORTH WITH A SURFACE LOW AND WAVE MOVING
NORTHEAST ALONG THAT FRONTAL ZONE AND SPREADS CLOUDS AND
PRECIPITATION NORTHEAST ACROSS THE AREA TUESDAY. ON THE OTHER HAND
THE ECMWF DOES NOT LINK A WAVE UP FROM THE SOUTH WITH JUST AN
ISOLATED CHANCE. PUT A 30 POP IN TUESDAY AFTERNOON. SURFACE HIGH
PRESSURE BUILDS IN FOR WEDNESDAY WITH A SHORTWAVE RIDGE ALOFT.
&&
.AVIATION /22Z WEDNESDAY THROUGH MONDAY/...
UPDATED AT 200 PM...GENERALLY MVFR CIGS ACROSS THE AREA. PATCH OF
SHOWERS MOVING ACROSS NORTHEAST PA INTO THE CATSKILLS WITH IFR
CIGS OVER HIGHER TERRAIN. A LINE OF SCATTERED SHOWERS AND
THUNDERSTORMS IS EXPECTED TO MOVE ACROSS WESTERN NEW YORK INTO THE
FINGER LAKES REGION BETWEEN 21Z AND 00Z AND CONTINUE EAST EXITING
THE AREA BETWEEN 03Z AND 05Z. OVERNIGHT MVFR CIGS ARE EXPECTED TO
CONTINUE WITH IFR ACROSS THE HIGHER TERRAIN. THERE IS A CHANCE OF
SHOWERS MOVING AFTER 06Z AND SOME MVFR VSBYS IN LIGHT FOG.
WINDS WILL BE S TO SSW AT 10 TO 15 KTS THIS AFTERNOON AND 5 TO 15
KTS TONIGHT.
OUTLOOK...
THU AND THU NGT...MVFR IN SHRA AND TSRA.
FRI...VFR BUT MVFR IN SCATTERED SHRA/TSRA MAINLY SOUTH.
SAT THRU MON...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...PVN/TAC
NEAR TERM...PVN/TAC
SHORT TERM...PVN
LONG TERM...BMW
AVIATION...BMW
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
249 PM EDT WED AUG 7 2013
.SYNOPSIS...
RAIN AND THUNDER CHANCES INCREASE LATE THIS AFTERNOON AS A LONG AWAITED
COLD FRONT DESCENDS UPON THE AREA. THIS FEATURE WILL THEN STALL
WEST OF THE AREA BY MORNING KEEPING THE THREAT FOR CONTINUED
SHOWERS AND STORMS IN THE FORECAST THROUGH THE REMAINDER OF THE
WORK WEEK. THIS FRONTAL PASSAGE LOOKS TO FINALLY OCCUR SOMETIME
FRIDAY EVENING.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
245 PM UPDATE...
SFC LOPRES JUST SOUTH OF HUDSON BAY HAS DRAPED A CDFNT DOWN ACRS LK
HURON AND SWWRD INTO NRN MO. AT THE SAME TIME CONVECTION THAT DVLPD
OVRNGT HAS THROWN OUT A GUST FRONT AND HAS ALLOWED STORMS TO DVLP
ACRS NRN OH. MAIN AREA OF STORMS ACRS SRN ONTARIO HAS LIFTED NORTH
AS EXPECTED WITH MAIN S/WV ROTATING ARND BASE OF HUDSON BAY TROF.
TIMING ON THIS AFOREMENTIONED LINE OF STORMS PLACES IT INTO EXTRM WRN
ZONES BY 21Z THIS AFTN AND WL WORK TWD CNTRL PART OF CWA BY 00Z.
THIS LOOKS TO BE KICKED OFF BY S/WV WORKING ITS WAY EAST ACRS NRN OH
AND IT APPEARS TO BE HEADING A LITTLE SOUTH OF EAST. THUS, WL
MAINTAIN LKLY POPS THRU TONIGHT WITH CONTINUAL MOISTURE BEING PUMPED
INTO REGION ON LLJ AND PW VALUES INCRSG TO NEAR 1.50 INCHES AND ANY
SUBTLE S/WVS THAT ENCROACH UPON THE AREA. BULLSEYE OF QPF ALONG THE
I-81 CORRIDOR ADVERTISED BY 12Z GFS AND LATEST RAP APPEARS TO BE A
RESULT OF CONVECTIVE FEEDBACK AND HV DISCOUNTED THIS SOLN. THINK
THAT AREAL AVGS WL LKLY BE BETWEEN 0.25 AND 0.50 INCHES.
AS FOR OVRNGT MINS DO NOT THINK TEMPS WL MV MUCH AS CLDS RMN
ENTRENCHED OVR AREA. FCST LOWS WL BOTTOM OUT IN THE L/M 60S.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/...
245 PM UPDATE...
FRONTAL BNDRY WL STALL OUT THUR MRNG JUST TO THE WEST OF THE AREA
AND RMN THERE INTO FRIDAY. VRY LITTLE MIXING WL OCCUR DRG THE DAY AS
AREA WL LKLY BE SOCKED IN WITH CLDS ONCE AGAIN. MAX TEMPS WL JUST
BARELY TOP OUT IN THE 80S. CAPES WL BE SIMILAR TO WED WITH VALUES
APPCHG 1000 J/KG BUT WIND SHEAR IS EXPECTED TO DROP OFF DRG THE DAY.
PW VALUES PROGGED TO APPCH 2.00 INCHES DRG THE DAY THUS ANY STORM
THAT DVLPS MAY PRODUCE MODERATE TO HVY RAIN.
LKLY POPS WL CONTINUE TOMORROW NGT AS BNDRY RMNS STALLED OUT TO THE
WEST. MED RANGE MODELS HINTING AT SFC LOPRES RIDING UP ALONG THE
FRONT THU NGT AND HELPING GIVE THE FRONT A LITTLE SHOVE TO THE
SOUTH.
FROPA NOW LOOKS TO OCCUR DRG THE DAY FRIDAY. THUS, HV TAKEN OUT PCPN
AFT 12Z SATURDAY. NO OTHER CHGS NEEDED TO THE END OF THE SHORT TERM
WITH PERHAPS SOME LINGERING SHOWERS ON FRIDAY WITH RMNG UL WV MVG
THRU BHND FRONT. ELONGATED VORT MAX PROGGED TO MV THRU ON SATURDAY
BUT WITH DRY AIRMASS IN PLACE NOT EXPECTING MUCH MORE THAN CLDS AT
THIS POINT.
&&
.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
200 PM UPDATE...
AREA REMAINS UNDER A BROAD LONG WAVE UPPER LEVEL TROUGH THROUGH
THE PERIOD AND SLIGHTLY COOLER THAN NORMAL TEMPERATURES WITH HIGHS
IN LOWER TO MIDDLE 70S AND NIGHTTIME LOWS IN THE 50S.
A FRONT THAT MOVED THROUGH THE AREA EARLY SATURDAY IS FORECAST TO
STALL IN A EAST-WEST MANNER ACROSS VIRGINA SATURDAY NIGHT INTO SUNDAY.
FROM THIS POINT MODELS HAVE DIFFERENCES OF TIMING AND POSITIONING
OF WAVES MOVING EASTWARD ALONG THIS FRONT THROUGH MIDWEEK CAUSING
SOME UNCERTAINTY IN THE FORECAST.
FORECASTED CLOUDS TO SPREAD NORTH WITH A WAVE ON SUNDAY BUT JUST
PLACED A SLIGHT CHANCE THUNDERSTORMS IN THE POCONOS FOR SUNDAY
AFTERNOON. HIGH PRESSURE BUILDS ACROSS SUNDAY NIGHT BEHIND THIS
WAVE. A SHORT-WAVE MOVING AROUND THE UPR LEVEL LOW TO OUR NORTH
MAY BRING A SLIGHT CHANCE OF SHOWERS OR THUNDERSTORMS IN THE
AFTERNOON MONDAY.
UNCERTAINTY INCREASES TUESDAY AS GFS LINKS A SHORT-WAVE MOVING
AROUND THE UPR LOW TO THE NORTH WITH A SURFACE LOW AND WAVE MOVING
NORTHEAST ALONG THAT FRONTAL ZONE AND SPREADS CLOUDS AND
PRECIPITATION NORTHEAST ACROSS THE AREA TUESDAY. ON THE OTHER HAND
THE ECMWF DOES NOT LINK A WAVE UP FROM THE SOUTH WITH JUST AN
ISOLATED CHANCE. PUT A 30 POP IN TUESDAY AFTERNOON. SURFACE HIGH
PRESSURE BUILDS IN FOR WEDNESDAY WITH A SHORTWAVE RIDGE ALOFT.
&&
.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
UPDATED AT 200 PM...GENERALLY MVFR CIGS ACROSS THE AREA. PATCH OF
SHOWERS MOVING ACROSS NORTHEAST PA INTO THE CATSKILLS WITH IFR
CIGS OVER HIGHER TERRAIN. A LINE OF SCATTERED SHOWERS AND
THUNDERSTORMS IS EXPECTED TO MOVE ACROSS WESTERN NEW YORK INTO THE
FINGER LAKES REGION BETWEEN 21Z AND 00Z AND CONTINUE EAST EXITING
THE AREA BETWEEN 03Z AND 05Z. OVERNIGHT MVFR CIGS ARE EXPECTED TO
CONTINUE WITH IFR ACROSS THE HIGHER TERRAIN. THERE IS A CHANCE OF
SHOWERS MOVING AFTER 06Z AND SOME MVFR VSBYS IN LIGHT FOG.
WINDS WILL BE S TO SSW AT 10 TO 15 KTS THIS AFTERNOON AND 5 TO 15
KTS TONIGHT.
OUTLOOK...
THU AND THU NGT...MVFR IN SHRA AND TSRA.
FRI...VFR BUT MVFR IN SCATTERED SHRA/TSRA MAINLY SOUTH.
SAT THRU MON...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...PVN
NEAR TERM...PVN
SHORT TERM...PVN
LONG TERM...BMW
AVIATION...BMW
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
157 PM EDT WED AUG 7 2013
.SYNOPSIS...
A WEAK WARM FRONT LIFTING NORTH FROM THE OHIO VALLEY WILL LEAD TO
SCATTERED SHOWERS ALONG WITH A FEW RUMBLES OF THUNDER MAINLY ALONG
AND WEST OF THE INTERSTATE 81 CORRIDOR BY THIS AFTERNOON. RAIN AND
THUNDER CHANCES WILL INCREASE AREAWIDE BEGINNING TONIGHT AS A
LONG AWAITED COLD FRONT DESCENDS UPON THE AREA. THIS FEATURE WILL
THEN STALL ACROSS THE AREA BY THURSDAY MORNING KEEPING THE THREAT
FOR CONTINUED SHOWERS AND STORMS IN THE FORECAST THROUGH THE
REMAINDER OF THE WORK WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
1 PM UPDATE...ANOTHER GRID UPDATE TO LOWER MAX TEMPS AS CLDS ARE
HANGING TUFF ACRS CWA THIS AFTN. THIN CLDS ARE AS CLOSE AS OUR WRN
BORDER BUT EXPECT CLDS WL NOT BREAK UP WITH SRLY FLOW CONTG TO
PUMP MOISTURE INTO CNTRL NY. THUS, HV GONE CLDY AREAWIDE FOR TDA
WITH HIGHS IN SOME LOCALES STRUGGLING TO REACH 70F. NOT OVERLY
IMPRESSED WITH SVR CONVECTIVE CHCS THIS AFTN AS WRN NY APPEARS TO
HV THE BEST INSTABILITY, HWVR WL HV TO WATCH ANY STORMS THAT ARE
ABLE TO MV INTO THE REGION AS LOW-LVL WIND SHEAR IS CERTAINLY
SUBSTANTIAL. TIMING ON CONVECTIVE LINE ACRS ONTARIO AND NWPA PUTS
IT INTO EXTRM WRN ZONES BY 21Z.
1045 AM UPDATE... CONVECTION IS BEGINNING TO DVLP ON GUST FRONT
OVR NRN OHIO AT THIS TIME. MCS NOW OVR SRN ONTARIO/MICHIGAN HAS
DVLPD AHD OF MAIN UPR WV AND THIS SHUD BEGIN TO FIZZLE THRU THE
DAY. SHUD ALSO HEAD OFF JUST TO THE NORTH OF CWA PER LATEST HIRES
MODELS IN 1000-500MB THICKNESS FIELDS. MAIN QUESTION IS WHAT KIND
OF REMNANT WV THIS MCS CAN DISLODGE TWD THE FA THIS AFTN. EML
PRESENT ON 12Z ILN SOUNDING EXPECTED TO SPREAD INTO WRN ZONES THIS
AFTN. IF ANYTHING CAN DVLP THIS AFTN WHICH LATEST MODELS ARE
HOLDING QPF OFF UNTIL AFT 00Z, WITH EXCEPTION OF HRRR AND RAP,
POTENTIAL EXISTS FOR ISOLD SVR. CAPES FCST TO BE ON THE ORDER OF
1000 J/KG AND BULK SHEAR VALUES OF 20-30KTS IN THE 0-1 AND 0-3KM
LAYERS WITH QUITE A BIT OF DIRECTIONAL SHEAR PRESENT PER KELM RAP
SNDGS.
SEE NO REASON TO CHG POP FCST AT THIS TIME WITH SCTD SHOWERS AND
ISOLD THUNDER ACRS WRN ZONES AFT 18Z AND THEN INCRSG TO SCTD
THUNDER LATE THIS AFTN. WL CONTINUE TO MONITOR FOR ANY CHGS TO
CURRENT THINKING. ALSO RMVD MENTION OF ISOLD SHOWERS ACRS SRN
ZONES IN MARINE LYR FOR THE NEXT COUPLE OF HOURS.
WITH EXTENSIVE CLD CVR ACRS THE REGION AND TEMPS ONLY RISING 1-2
DEGREES OVR THE PAST HR HV LEFT MAX TEMP FCST UNCHANGED. MAX TEMPS
SHUD RISE TO FCST VALUES IF BREAKS CAN DVLP IN CLDS. FOR NOW, WILL
JUST SIT AND WAIT BFR MAKING ANY CHGS TO TEMP/POP/WX GRIDS.
625 AM UPDATE...
TOOK THE LIBERTY OF INCREASING HIGH TEMPS A DEGREE OR TWO FOR
LATER TODAY AS LOW STRATUS UP HERE AT THE AIRPORT LOOKS PRETTY
THIN. AS A RESULT...A LITTLE MORE SUNSHINE IS EXPECTED WHICH
SHOULD HELP IN THE DIURNAL HEATING DEPARTMENT. NO OTHER CHANGES
NEEDED AT THE PRESENT TIME.
PREVIOUS NEAR TERM DISCUSSION...
EARLY MORNING 11-3.9U SATELLITE IMAGERY SHOWING LOW STRATUS
CONTINUING TO WORK NORTH INTO THE FCST AREA AS SOUTHERLY RETURN
FLOW INCREASES ON THE BACKSIDE OF HIGH PRESSURE NOW POSITIONED OF
THE MID-ATLANTIC COAST. THE PRESENCE OF THESE CLOUDS MAKES TODAY/S
FORECAST ANYTHING BUT EASY AS CLOUD COVER WILL HAVE SIGNIFICANT
IMPACTS ON BOTH THE DESTABILIZATION POTENTIAL AND HIGH TEMP
FORECASTS LATER TODAY. IN ANY EVENT ...UPPER-LEVEL PATTERN REMAINS
DOMINATED BY A BROAD UPPER LOW WHICH CONTINUES TO SPIN JUST SOUTH
OF HUDSON BAY THIS MORNING...WITH DEVELOPING DIFFLUENT FLOW
DOWNSTREAM ACROSS THE CENTRAL AND EASTERN GREAT LAKES. EMBEDDED
WITHIN THIS FLOW IS A FAIRLY DECENT SHORTWAVE AND VERY DISCERNIBLE
MCS WHICH CONTINUES TO WORK THROUGH WESTERN/CENTRAL MICHIGAN THIS
MORNING. IN FACT...RADAR APPEARANCE OF THIS MCS IS VERY IMPRESSIVE
WITH ALL INDICATIONS SUGGESTING THIS FEATURE HAS ORGANIZED INTO A
WELL- DEFINED DERECHO WITH WIDESPREAD WIND DAMAGE REPORTED AS FAR
WEST AS SOUTHEASTERN NORTH DAKOTA. CURRENT THINKING IS THIS
FEATURE WILL WEAKEN WITH FURTHER EASTWARD PROGRESS INTO SOUTHERN
ONTARIO AS ATMOSPHERE DOWNSTREAM REMAINS MUCH MORE STABLE.
LINGERING MCV/SHORTWAVE ENERGY LIKELY TO PASS JUST TO OUR NORTH
LATER THIS MORNING AS FLOW UPPER FLOW BECOMES MORE SOUTHWEST
DOWNSTREAM OVER THE EASTERN LAKES.
MOVING INTO TODAY...FCST MODELS CONTINUE TO HINT AT DEVELOPING
SHWRS/ISO STORMS AS DIURNAL HEATING COMBINES WITH THE PASSING OF A
FEW WEAK SHORTWAVES. THAT SAID...MODEL INSTABILITY REMAINS
ANYTHING BUT IMPRESSIVE WITH BOTH GFS AND NAM SUGGESTING MLCAPE
VALUES OF MAYBE A FEW HUNDRED JOULES AT BEST...MAINLY ALONG AND
WEST OF THE I-81 CORRIDOR. CONSIDERING FORCING REMAINS FAIRLY
WEAK DESPITE WHAT APPEARS TO BE A WEAK WARM FRONT LIFTING NORTH FROM
THE OHIO VLY...AREAL COVERAGE OF SHWRS/STORMS LIKELY TO REMAIN IN
THE ISO-SCT CATEGORY. FOR NOW HAVE MAINTAINED THIS TREND FROM
PREVIOUS FORECASTS WITH THUNDER MENTION MAINLY CONFINED TO AREAS
OUTLINED ABOVE. TEMP FORECAST ANYTHING BUT EASY DUE TO LOW STRATUS
WHICH SOME MODELS SUGGEST WILL BE WITH US FOR A GOOD PORTION OF
THE HEATING CYCLE. WITH THIS BEING THE CASE...HAVE KEPT HIGHEST
VALUES (UPPER 70S) CONFINED TO THE IMMEDIATE LAKE PLAIN...WITH
COOLER VALUES FROM THE FINGER LAKES AND POINTS SOUTH. OBVIOUSLY A
FEW BREAKS HERE AND THERE MAY YIELD WARMER VALUES THAN CURRENTLY
FORECAST...ESPECIALLY FOR TWIN TIERS AND FINGER LAKES AREAS.
BY TONIGHT...COLD FRONT EXPECTED TO DROP SOUTH ACROSS THE FCST
AREA AFTER 00Z THIS EVENING. AS THIS OCCURS...EXPECT SHWRS/STORMS
TO INCREASE WITH TIME AND THUS HAVE MAINTAINED NUMEROUS MENTION FOR
THE REGION DURING THE ENTIRE PERIOD. OVERNIGHT LOWS SHOULD BE
FAIRLY WARM WITH CLOUDS/PRECIP IN THE VICINITY WITH VALUES LARGELY
FALLING INTO THE LOWER TO MIDDLE 60S AREAWIDE.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AFOREMENTIONED FRONT TO STALL ACROSS THE FCST AREA ON THURSDAY
WITH CONTINUES CHANCES FOR SHWRS/STORMS THROUGH MUCH OF THE
DAYLIGHT HRS. FCST MODELS TO HINT AT BETTER INSTABILITY GENERATION
DURING THE DAY WITH BOTH GFS AND NAM OFFERING ROUGHLY 500-1000
J/KG. THIS COMBINED WITH 0-6 KM BULK SHEAR VECTORS OF 30-40 KTS
SUGGESTS THAT SOME SEVERE WILL BE POSSIBLE IF STORMS BECOME
ORGANIZED. CURRENT SPC DAY 2 OUTLOOK HIGHLIGHTS OUR AREA WITH A "SEE
TEXT" FOR THE POSSIBILITY OF ORGANIZED MULTICELLS OFFERING AN
ISOLATED WIND/HAIL THREAT. AS HAS BEEN THE CASE IN RECENT
DAYS...OVERALL SYNOPTIC FORCING LOOKS FAIRLY WEAK DESPITE FRONTAL
BOUNDARY REMAINING POSITIONED OVER THE AREA.
BEYOND THIS...SHWRS/STORMS REMAIN IN THE FCST THROUGH FRI WITH
INDICATIONS SUGGESTING BEST FORCING WILL ARRIVE FRI NGT/EARLY SAT
AS HUDSON BAY UPPER LOW BEGINS TO SHIFT EAST AND TAKE ON A
NEGATIVE TILT WITH TIME. AS THIS OCCURS...MODELS SHOW A SFC LOW
LIFTING NORTH FROM THE OHIO VLY WITH A PRETTY GOOD SLUG OF
MOISTURE AS PWAT VALUES EXCEED 2" BY 00Z SAT. SOME AREAS MAY SEE
A BRIEF PERIOD OF MODERATE TO HEAVY RAIN FRI NGT/EARLY SAT BUT
MAIN AREA SHOULD MOVE FAIRLY QUICKLY TO THE NORTHEAST...THUS NO
SIGNIFICANT IMPACTS EXPECTED.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
200 PM UPDATE...
AREA REMAINS UNDER A BROAD LONG WAVE UPPER LEVEL TROUGH THROUGH
THE PERIOD AND SLIGHTLY COOLER THAN NORMAL TEMPERATURES WITH HIGHS
IN LOWER TO MIDDLE 70S AND NIGHTTIME LOWS IN THE 50S.
A FRONT THAT MOVED THROUGH THE AREA EARLY SATURDAY IS FORECAST TO
STALL IN A EAST-WEST MANNER ACROSS VIRGINA SATURDAY NIGHT INTO SUNDAY.
FROM THIS POINT MODELS HAVE DIFFERENCES OF TIMING AND POSITIONING
OF WAVES MOVING EASTWARD ALONG THIS FRONT THROUGH MIDWEEK CAUSING
SOME UNCERTAINTY IN THE FORECAST.
FORECASTED CLOUDS TO SPREAD NORTH WITH A WAVE ON SUNDAY BUT JUST
PLACED A SLIGHT CHANCE THUNDERSTORMS IN THE POCONOS FOR SUNDAY
AFTERNOON. HIGH PRESSURE BUILDS ACROSS SUNDAY NIGHT BEHIND THIS
WAVE. A SHORT-WAVE MOVING AROUND THE UPR LEVEL LOW TO OUR NORTH
MAY BRING A SLIGHT CHANCE OF SHOWERS OR THUNDERSTORMS IN THE
AFTERNOON MONDAY.
UNCERTAINTY INCREASES TUESDAY AS GFS LINKS A SHORT-WAVE MOVING
AROUND THE UPR LOW TO THE NORTH WITH A SURFACE LOW AND WAVE MOVING
NORTHEAST ALONG THAT FRONTAL ZONE AND SPREADS CLOUDS AND
PRECIPITATION NORTHEAST ACROSS THE AREA TUESDAY. ON THE OTHER HAND
THE ECMWF DOES NOT LINK A WAVE UP FROM THE SOUTH WITH JUST AN
ISOLATED CHANCE. PUT A 30 POP IN TUESDAY AFTERNOON. SURFACE HIGH
PRESSURE BUILDS IN FOR WEDNESDAY WITH A SHORTWAVE RIDGE ALOFT.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
UPDATED AT 200 PM...GENERALLY MVFR CIGS ACROSS THE AREA. PATCH OF
SHOWERS MOVING ACROSS NORTHEAST PA INTO THE CATSKILLS WITH IFR
CIGS OVER HIGHER TERRAIN. A LINE OF SCATTERED SHOWERS AND
THUNDERSTORMS IS EXPECTED TO MOVE ACROSS WESTERN NEW YORK INTO THE
FINGER LAKES REGION BETWEEN 21Z AND 00Z AND CONTINUE EAST EXITING
THE AREA BETWEEN 03Z AND 05Z. OVERNIGHT MVFR CIGS ARE EXPECTED TO
CONTINUE WITH IFR ACROSS THE HIGHER TERRAIN. THERE IS A CHANCE OF
SHOWERS MOVING AFTER 06Z AND SOME MVFR VSBYS IN LIGHT FOG.
WINDS WILL BE S TO SSW AT 10 TO 15 KTS THIS AFTERNOON AND 5 TO 15
KTS TONIGHT.
OUTLOOK...
THU AND THU NGT...MVFR IN SHRA AND TSRA.
FRI...VFR BUT MVFR IN SCATTERED SHRA/TSRA MAINLY SOUTH.
SAT THRU MON...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...CMG/PVN
NEAR TERM...CMG/PVN
SHORT TERM...CMG
LONG TERM...BMW
AVIATION...BMW
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
107 PM EDT WED AUG 7 2013
.SYNOPSIS...
A WEAK WARM FRONT LIFTING NORTH FROM THE OHIO VALLEY WILL LEAD TO
SCATTERED SHOWERS ALONG WITH A FEW RUMBLES OF THUNDER MAINLY ALONG
AND WEST OF THE INTERSTATE 81 CORRIDOR BY THIS AFTERNOON. RAIN AND
THUNDER CHANCES WILL INCREASE AREAWIDE BEGINNING TONIGHT AS A
LONG AWAITED COLD FRONT DESCENDS UPON THE AREA. THIS FEATURE WILL
THEN STALL ACROSS THE AREA BY THURSDAY MORNING KEEPING THE THREAT
FOR CONTINUED SHOWERS AND STORMS IN THE FORECAST THROUGH THE
REMAINDER OF THE WORK WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
1 PM UPDATE...ANOTHER GRID UPDATE TO LOWER MAX TEMPS AS CLDS ARE
HANGING TUFF ACRS CWA THIS AFTN. THIN CLDS ARE AS CLOSE AS OUR WRN
BORDER BUT EXPECT CLDS WL NOT BREAK UP WITH SRLY FLOW CONTG TO
PUMP MOISTURE INTO CNTRL NY. THUS, HV GONE CLDY AREAWIDE FOR TDA
WITH HIGHS IN SOME LOCALES STRUGGLING TO REACH 70F. NOT OVERLY
IMPRESSED WITH SVR CONVECTIVE CHCS THIS AFTN AS WRN NY APPEARS TO
HV THE BEST INSTABILITY, HWVR WL HV TO WATCH ANY STORMS THAT ARE
ABLE TO MV INTO THE REGION AS LOW-LVL WIND SHEAR IS CERTAINLY
SUBSTANTIAL. TIMING ON CONVECTIVE LINE ACRS ONTARIO AND NWPA PUTS
IT INTO EXTRM WRN ZONES BY 21Z.
1045 AM UPDATE... CONVECTION IS BEGINNING TO DVLP ON GUST FRONT
OVR NRN OHIO AT THIS TIME. MCS NOW OVR SRN ONTARIO/MICHIGAN HAS
DVLPD AHD OF MAIN UPR WV AND THIS SHUD BEGIN TO FIZZLE THRU THE
DAY. SHUD ALSO HEAD OFF JUST TO THE NORTH OF CWA PER LATEST HIRES
MODELS IN 1000-500MB THICKNESS FIELDS. MAIN QUESTION IS WHAT KIND
OF REMNANT WV THIS MCS CAN DISLODGE TWD THE FA THIS AFTN. EML
PRESENT ON 12Z ILN SOUNDING EXPECTED TO SPREAD INTO WRN ZONES THIS
AFTN. IF ANYTHING CAN DVLP THIS AFTN WHICH LATEST MODELS ARE
HOLDING QPF OFF UNTIL AFT 00Z, WITH EXCEPTION OF HRRR AND RAP,
POTENTIAL EXISTS FOR ISOLD SVR. CAPES FCST TO BE ON THE ORDER OF
1000 J/KG AND BULK SHEAR VALUES OF 20-30KTS IN THE 0-1 AND 0-3KM
LAYERS WITH QUITE A BIT OF DIRECTIONAL SHEAR PRESENT PER KELM RAP
SNDGS.
SEE NO REASON TO CHG POP FCST AT THIS TIME WITH SCTD SHOWERS AND
ISOLD THUNDER ACRS WRN ZONES AFT 18Z AND THEN INCRSG TO SCTD
THUNDER LATE THIS AFTN. WL CONTINUE TO MONITOR FOR ANY CHGS TO
CURRENT THINKING. ALSO RMVD MENTION OF ISOLD SHOWERS ACRS SRN
ZONES IN MARINE LYR FOR THE NEXT COUPLE OF HOURS.
WITH EXTENSIVE CLD CVR ACRS THE REGION AND TEMPS ONLY RISING 1-2
DEGREES OVR THE PAST HR HV LEFT MAX TEMP FCST UNCHANGED. MAX TEMPS
SHUD RISE TO FCST VALUES IF BREAKS CAN DVLP IN CLDS. FOR NOW, WILL
JUST SIT AND WAIT BFR MAKING ANY CHGS TO TEMP/POP/WX GRIDS.
625 AM UPDATE...
TOOK THE LIBERTY OF INCREASING HIGH TEMPS A DEGREE OR TWO FOR
LATER TODAY AS LOW STRATUS UP HERE AT THE AIRPORT LOOKS PRETTY
THIN. AS A RESULT...A LITTLE MORE SUNSHINE IS EXPECTED WHICH
SHOULD HELP IN THE DIURNAL HEATING DEPARTMENT. NO OTHER CHANGES
NEEDED AT THE PRESENT TIME.
PREVIOUS NEAR TERM DISCUSSION...
EARLY MORNING 11-3.9U SATELLITE IMAGERY SHOWING LOW STRATUS
CONTINUING TO WORK NORTH INTO THE FCST AREA AS SOUTHERLY RETURN
FLOW INCREASES ON THE BACKSIDE OF HIGH PRESSURE NOW POSITIONED OF
THE MID-ATLANTIC COAST. THE PRESENCE OF THESE CLOUDS MAKES TODAY/S
FORECAST ANYTHING BUT EASY AS CLOUD COVER WILL HAVE SIGNIFICANT
IMPACTS ON BOTH THE DESTABILIZATION POTENTIAL AND HIGH TEMP
FORECASTS LATER TODAY. IN ANY EVENT ...UPPER-LEVEL PATTERN REMAINS
DOMINATED BY A BROAD UPPER LOW WHICH CONTINUES TO SPIN JUST SOUTH
OF HUDSON BAY THIS MORNING...WITH DEVELOPING DIFFLUENT FLOW
DOWNSTREAM ACROSS THE CENTRAL AND EASTERN GREAT LAKES. EMBEDDED
WITHIN THIS FLOW IS A FAIRLY DECENT SHORTWAVE AND VERY DISCERNIBLE
MCS WHICH CONTINUES TO WORK THROUGH WESTERN/CENTRAL MICHIGAN THIS
MORNING. IN FACT...RADAR APPEARANCE OF THIS MCS IS VERY IMPRESSIVE
WITH ALL INDICATIONS SUGGESTING THIS FEATURE HAS ORGANIZED INTO A
WELL- DEFINED DERECHO WITH WIDESPREAD WIND DAMAGE REPORTED AS FAR
WEST AS SOUTHEASTERN NORTH DAKOTA. CURRENT THINKING IS THIS
FEATURE WILL WEAKEN WITH FURTHER EASTWARD PROGRESS INTO SOUTHERN
ONTARIO AS ATMOSPHERE DOWNSTREAM REMAINS MUCH MORE STABLE.
LINGERING MCV/SHORTWAVE ENERGY LIKELY TO PASS JUST TO OUR NORTH
LATER THIS MORNING AS FLOW UPPER FLOW BECOMES MORE SOUTHWEST
DOWNSTREAM OVER THE EASTERN LAKES.
MOVING INTO TODAY...FCST MODELS CONTINUE TO HINT AT DEVELOPING
SHWRS/ISO STORMS AS DIURNAL HEATING COMBINES WITH THE PASSING OF A
FEW WEAK SHORTWAVES. THAT SAID...MODEL INSTABILITY REMAINS
ANYTHING BUT IMPRESSIVE WITH BOTH GFS AND NAM SUGGESTING MLCAPE
VALUES OF MAYBE A FEW HUNDRED JOULES AT BEST...MAINLY ALONG AND
WEST OF THE I-81 CORRIDOR. CONSIDERING FORCING REMAINS FAIRLY
WEAK DESPITE WHAT APPEARS TO BE A WEAK WARM FRONT LIFTING NORTH FROM
THE OHIO VLY...AREAL COVERAGE OF SHWRS/STORMS LIKELY TO REMAIN IN
THE ISO-SCT CATEGORY. FOR NOW HAVE MAINTAINED THIS TREND FROM
PREVIOUS FORECASTS WITH THUNDER MENTION MAINLY CONFINED TO AREAS
OUTLINED ABOVE. TEMP FORECAST ANYTHING BUT EASY DUE TO LOW STRATUS
WHICH SOME MODELS SUGGEST WILL BE WITH US FOR A GOOD PORTION OF
THE HEATING CYCLE. WITH THIS BEING THE CASE...HAVE KEPT HIGHEST
VALUES (UPPER 70S) CONFINED TO THE IMMEDIATE LAKE PLAIN...WITH
COOLER VALUES FROM THE FINGER LAKES AND POINTS SOUTH. OBVIOUSLY A
FEW BREAKS HERE AND THERE MAY YIELD WARMER VALUES THAN CURRENTLY
FORECAST...ESPECIALLY FOR TWIN TIERS AND FINGER LAKES AREAS.
BY TONIGHT...COLD FRONT EXPECTED TO DROP SOUTH ACROSS THE FCST
AREA AFTER 00Z THIS EVENING. AS THIS OCCURS...EXPECT SHWRS/STORMS
TO INCREASE WITH TIME AND THUS HAVE MAINTAINED NUMEROUS MENTION FOR
THE REGION DURING THE ENTIRE PERIOD. OVERNIGHT LOWS SHOULD BE
FAIRLY WARM WITH CLOUDS/PRECIP IN THE VICINITY WITH VALUES LARGELY
FALLING INTO THE LOWER TO MIDDLE 60S AREAWIDE.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AFOREMENTIONED FRONT TO STALL ACROSS THE FCST AREA ON THURSDAY
WITH CONTINUES CHANCES FOR SHWRS/STORMS THROUGH MUCH OF THE
DAYLIGHT HRS. FCST MODELS TO HINT AT BETTER INSTABILITY GENERATION
DURING THE DAY WITH BOTH GFS AND NAM OFFERING ROUGHLY 500-1000
J/KG. THIS COMBINED WITH 0-6 KM BULK SHEAR VECTORS OF 30-40 KTS
SUGGESTS THAT SOME SEVERE WILL BE POSSIBLE IF STORMS BECOME
ORGANIZED. CURRENT SPC DAY 2 OUTLOOK HIGHLIGHTS OUR AREA WITH A "SEE
TEXT" FOR THE POSSIBILITY OF ORGANIZED MULTICELLS OFFERING AN
ISOLATED WIND/HAIL THREAT. AS HAS BEEN THE CASE IN RECENT
DAYS...OVERALL SYNOPTIC FORCING LOOKS FAIRLY WEAK DESPITE FRONTAL
BOUNDARY REMAINING POSITIONED OVER THE AREA.
BEYOND THIS...SHWRS/STORMS REMAIN IN THE FCST THROUGH FRI WITH
INDICATIONS SUGGESTING BEST FORCING WILL ARRIVE FRI NGT/EARLY SAT
AS HUDSON BAY UPPER LOW BEGINS TO SHIFT EAST AND TAKE ON A
NEGATIVE TILT WITH TIME. AS THIS OCCURS...MODELS SHOW A SFC LOW
LIFTING NORTH FROM THE OHIO VLY WITH A PRETTY GOOD SLUG OF
MOISTURE AS PWAT VALUES EXCEED 2" BY 00Z SAT. SOME AREAS MAY SEE
A BRIEF PERIOD OF MODERATE TO HEAVY RAIN FRI NGT/EARLY SAT BUT
MAIN AREA SHOULD MOVE FAIRLY QUICKLY TO THE NORTHEAST...THUS NO
SIGNIFICANT IMPACTS EXPECTED.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
200 PM UPDATE...
FRIDAY NIGHT WE WILL BE IN THE PROCESS OF MOVING A COLD FRONT
THROUGH OUR AREA. SOME SHOWERS MAY LINGER THROUGH FRIDAY
NIGHT...ESPECIALLY ACROSS NEPA. A MARKED PUNCH OF DRIER AIR IN THE
MID LEVELS OF THE ATMOSPHERE WILL RACE OUT OF THE GREAT LAKES AND
BE WITH US BY 12Z SATURDAY. THIS WILL END ANY SHOWER THREAT AND
DRY US OUT FOR SATURDAY.
HIGH PRESSURE WILL CONTROL OUR WEATHER SUNDAY INTO EARLY NEXT WEEK
WITH A BEAUTIFUL STRETCH OF WEATHER. IT WILL REMAIN BELOW
AVERAGE WITH 850 TEMPS IN THE LOWER TEENS SUPPORTING HIGHS IN
LOWER TO MIDDLE 70S AND NIGHTTIME LOWS IN THE 40S AND 50S.
&&
.AVIATION /17Z WEDNESDAY THROUGH SUNDAY/...
UPDATED AT 630 AM... PATCHY MVFR CIGS WILL GIVE WAY TO VFR
CONDITIONS BY 14Z. VFR CONDITIONS WILL PERSIST THROUGH MOST OF
THIS AFTERNOON. SCATTERED SHOWERS AND THUNDERSTORMS LATE THIS
AFTERNOON THROUGH THIS EVENING WILL BE ACCOMPANIED BY SCATTERED
BRIEF PERIODS OF MVFR CIGS AND VSBYS. WINDS WILL BE LIGHT AND
VARIABLE THIS MORNING BECOMING SSW AT 10 TO 15 KTS THIS AFTERNOON
AND 5 TO 15 KTS TONIGHT.
OUTLOOK...
THU AND THU NGT...MVFR IN SHRA AND TSRA.
FRI...VFR BUT MVFR IN SCATTERED SHRA/TSRA MAINLY SOUTH.
SAT AND SUN...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...CMG/PVN
NEAR TERM...CMG/PVN
SHORT TERM...CMG
LONG TERM...HEDEN
AVIATION...MSE/TAC
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1048 AM EDT WED AUG 7 2013
.SYNOPSIS...
A WEAK WARM FRONT LIFTING NORTH FROM THE OHIO VALLEY WILL LEAD TO
SCATTERED SHOWERS ALONG WITH A FEW RUMBLES OF THUNDER MAINLY ALONG
AND WEST OF THE INTERSTATE 81 CORRIDOR BY THIS AFTERNOON. RAIN AND
THUNDER CHANCES WILL INCREASE AREAWIDE BEGINNING TONIGHT AS A
LONG AWAITED COLD FRONT DESCENDS UPON THE AREA. THIS FEATURE WILL
THEN STALL ACROSS THE AREA BY THURSDAY MORNING KEEPING THE THREAT
FOR CONTINUED SHOWERS AND STORMS IN THE FORECAST THROUGH THE
REMAINDER OF THE WORK WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
1045 AM UPDATE...
CONVECTION IS BEGINNING TO DVLP ON GUST FRONT OVR NRN OHIO AT THIS
TIME. MCS NOW OVR SRN ONTARIO/MICHIGAN HAS DVLPD AHD OF MAIN UPR
WV AND THIS SHUD BEGIN TO FIZZLE THRU THE DAY. SHUD ALSO HEAD OFF
JUST TO THE NORTH OF CWA PER LATEST HIRES MODELS IN 1000-500MB
THICKNESS FIELDS. MAIN QUESTION IS WHAT KIND OF REMNANT WV THIS
MCS CAN DISLODGE TWD THE FA THIS AFTN. EML PRESENT ON 12Z ILN
SOUNDING EXPECTED TO SPREAD INTO WRN ZONES THIS AFTN. IF ANYTHING
CAN DVLP THIS AFTN WHICH LATEST MODELS ARE HOLDING QPF OFF UNTIL
AFT 00Z, WITH EXCEPTION OF HRRR AND RAP, POTENTIAL EXISTS FOR
ISOLD SVR. CAPES FCST TO BE ON THE ORDER OF 1000 J/KG AND BULK
SHEAR VALUES OF 20-30KTS IN THE 0-1 AND 0-3KM LAYERS WITH QUITE A
BIT OF DIRECTIONAL SHEAR PRESENT PER KELM RAP SNDGS.
SEE NO REASON TO CHG POP FCST AT THIS TIME WITH SCTD SHOWERS AND
ISOLD THUNDER ACRS WRN ZONES AFT 18Z AND THEN INCRSG TO SCTD
THUNDER LATE THIS AFTN. WL CONTINUE TO MONITOR FOR ANY CHGS TO
CURRENT THINKING. ALSO RMVD MENTION OF ISOLD SHOWERS ACRS SRN
ZONES IN MARINE LYR FOR THE NEXT COUPLE OF HOURS.
WITH EXTENSIVE CLD CVR ACRS THE REGION AND TEMPS ONLY RISING 1-2
DEGREES OVR THE PAST HR HV LEFT MAX TEMP FCST UNCHANGED. MAX TEMPS
SHUD RISE TO FCST VALUES IF BREAKS CAN DVLP IN CLDS. FOR NOW, WILL
JUST SIT AND WAIT BFR MAKING ANY CHGS TO TEMP/POP/WX GRIDS.
625 AM UPDATE...
TOOK THE LIBERTY OF INCREASING HIGH TEMPS A DEGREE OR TWO FOR
LATER TODAY AS LOW STRATUS UP HERE AT THE AIRPORT LOOKS PRETTY
THIN. AS A RESULT...A LITTLE MORE SUNSHINE IS EXPECTED WHICH
SHOULD HELP IN THE DIURNAL HEATING DEPARTMENT. NO OTHER CHANGES
NEEDED AT THE PRESENT TIME.
PREVIOUS NEAR TERM DISCUSSION...
EARLY MORNING 11-3.9U SATELLITE IMAGERY SHOWING LOW STRATUS
CONTINUING TO WORK NORTH INTO THE FCST AREA AS SOUTHERLY RETURN
FLOW INCREASES ON THE BACKSIDE OF HIGH PRESSURE NOW POSITIONED OF
THE MID-ATLANTIC COAST. THE PRESENCE OF THESE CLOUDS MAKES TODAY/S
FORECAST ANYTHING BUT EASY AS CLOUD COVER WILL HAVE SIGNIFICANT
IMPACTS ON BOTH THE DESTABILIZATION POTENTIAL AND HIGH TEMP
FORECASTS LATER TODAY. IN ANY EVENT ...UPPER-LEVEL PATTERN REMAINS
DOMINATED BY A BROAD UPPER LOW WHICH CONTINUES TO SPIN JUST SOUTH
OF HUDSON BAY THIS MORNING...WITH DEVELOPING DIFFLUENT FLOW
DOWNSTREAM ACROSS THE CENTRAL AND EASTERN GREAT LAKES. EMBEDDED
WITHIN THIS FLOW IS A FAIRLY DECENT SHORTWAVE AND VERY DISCERNIBLE
MCS WHICH CONTINUES TO WORK THROUGH WESTERN/CENTRAL MICHIGAN THIS
MORNING. IN FACT...RADAR APPEARANCE OF THIS MCS IS VERY IMPRESSIVE
WITH ALL INDICATIONS SUGGESTING THIS FEATURE HAS ORGANIZED INTO A
WELL- DEFINED DERECHO WITH WIDESPREAD WIND DAMAGE REPORTED AS FAR
WEST AS SOUTHEASTERN NORTH DAKOTA. CURRENT THINKING IS THIS
FEATURE WILL WEAKEN WITH FURTHER EASTWARD PROGRESS INTO SOUTHERN
ONTARIO AS ATMOSPHERE DOWNSTREAM REMAINS MUCH MORE STABLE.
LINGERING MCV/SHORTWAVE ENERGY LIKELY TO PASS JUST TO OUR NORTH
LATER THIS MORNING AS FLOW UPPER FLOW BECOMES MORE SOUTHWEST
DOWNSTREAM OVER THE EASTERN LAKES.
MOVING INTO TODAY...FCST MODELS CONTINUE TO HINT AT DEVELOPING
SHWRS/ISO STORMS AS DIURNAL HEATING COMBINES WITH THE PASSING OF A
FEW WEAK SHORTWAVES. THAT SAID...MODEL INSTABILITY REMAINS
ANYTHING BUT IMPRESSIVE WITH BOTH GFS AND NAM SUGGESTING MLCAPE
VALUES OF MAYBE A FEW HUNDRED JOULES AT BEST...MAINLY ALONG AND
WEST OF THE I-81 CORRIDOR. CONSIDERING FORCING REMAINS FAIRLY
WEAK DESPITE WHAT APPEARS TO BE A WEAK WARM FRONT LIFTING NORTH FROM
THE OHIO VLY...AREAL COVERAGE OF SHWRS/STORMS LIKELY TO REMAIN IN
THE ISO-SCT CATEGORY. FOR NOW HAVE MAINTAINED THIS TREND FROM
PREVIOUS FORECASTS WITH THUNDER MENTION MAINLY CONFINED TO AREAS
OUTLINED ABOVE. TEMP FORECAST ANYTHING BUT EASY DUE TO LOW STRATUS
WHICH SOME MODELS SUGGEST WILL BE WITH US FOR A GOOD PORTION OF
THE HEATING CYCLE. WITH THIS BEING THE CASE...HAVE KEPT HIGHEST
VALUES (UPPER 70S) CONFINED TO THE IMMEDIATE LAKE PLAIN...WITH
COOLER VALUES FROM THE FINGER LAKES AND POINTS SOUTH. OBVIOUSLY A
FEW BREAKS HERE AND THERE MAY YIELD WARMER VALUES THAN CURRENTLY
FORECAST...ESPECIALLY FOR TWIN TIERS AND FINGER LAKES AREAS.
BY TONIGHT...COLD FRONT EXPECTED TO DROP SOUTH ACROSS THE FCST
AREA AFTER 00Z THIS EVENING. AS THIS OCCURS...EXPECT SHWRS/STORMS
TO INCREASE WITH TIME AND THUS HAVE MAINTAINED NUMEROUS MENTION FOR
THE REGION DURING THE ENTIRE PERIOD. OVERNIGHT LOWS SHOULD BE
FAIRLY WARM WITH CLOUDS/PRECIP IN THE VICINITY WITH VALUES LARGELY
FALLING INTO THE LOWER TO MIDDLE 60S AREAWIDE.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AFOREMENTIONED FRONT TO STALL ACROSS THE FCST AREA ON THURSDAY
WITH CONTINUES CHANCES FOR SHWRS/STORMS THROUGH MUCH OF THE
DAYLIGHT HRS. FCST MODELS TO HINT AT BETTER INSTABILITY GENERATION
DURING THE DAY WITH BOTH GFS AND NAM OFFERING ROUGHLY 500-1000
J/KG. THIS COMBINED WITH 0-6 KM BULK SHEAR VECTORS OF 30-40 KTS
SUGGESTS THAT SOME SEVERE WILL BE POSSIBLE IF STORMS BECOME
ORGANIZED. CURRENT SPC DAY 2 OUTLOOK HIGHLIGHTS OUR AREA WITH A "SEE
TEXT" FOR THE POSSIBILITY OF ORGANIZED MULTICELLS OFFERING AN
ISOLATED WIND/HAIL THREAT. AS HAS BEEN THE CASE IN RECENT
DAYS...OVERALL SYNOPTIC FORCING LOOKS FAIRLY WEAK DESPITE FRONTAL
BOUNDARY REMAINING POSITIONED OVER THE AREA.
BEYOND THIS...SHWRS/STORMS REMAIN IN THE FCST THROUGH FRI WITH
INDICATIONS SUGGESTING BEST FORCING WILL ARRIVE FRI NGT/EARLY SAT
AS HUDSON BAY UPPER LOW BEGINS TO SHIFT EAST AND TAKE ON A
NEGATIVE TILT WITH TIME. AS THIS OCCURS...MODELS SHOW A SFC LOW
LIFTING NORTH FROM THE OHIO VLY WITH A PRETTY GOOD SLUG OF
MOISTURE AS PWAT VALUES EXCEED 2" BY 00Z SAT. SOME AREAS MAY SEE
A BRIEF PERIOD OF MODERATE TO HEAVY RAIN FRI NGT/EARLY SAT BUT
MAIN AREA SHOULD MOVE FAIRLY QUICKLY TO THE NORTHEAST...THUS NO
SIGNIFICANT IMPACTS EXPECTED.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
200 PM UPDATE...
FRIDAY NIGHT WE WILL BE IN THE PROCESS OF MOVING A COLD FRONT
THROUGH OUR AREA. SOME SHOWERS MAY LINGER THROUGH FRIDAY
NIGHT...ESPECIALLY ACROSS NEPA. A MARKED PUNCH OF DRIER AIR IN THE
MID LEVELS OF THE ATMOSPHERE WILL RACE OUT OF THE GREAT LAKES AND
BE WITH US BY 12Z SATURDAY. THIS WILL END ANY SHOWER THREAT AND
DRY US OUT FOR SATURDAY.
HIGH PRESSURE WILL CONTROL OUR WEATHER SUNDAY INTO EARLY NEXT WEEK
WITH A BEAUTIFUL STRETCH OF WEATHER. IT WILL REMAIN BELOW
AVERAGE WITH 850 TEMPS IN THE LOWER TEENS SUPPORTING HIGHS IN
LOWER TO MIDDLE 70S AND NIGHTTIME LOWS IN THE 40S AND 50S.
&&
.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
UPDATED AT 630 AM... PATCHY MVFR CIGS WILL GIVE WAY TO VFR
CONDITIONS BY 14Z. VFR CONDITIONS WILL PERSIST THROUGH MOST OF
THIS AFTERNOON. SCATTERED SHOWERS AND THUNDERSTORMS LATE THIS
AFTERNOON THROUGH THIS EVENING WILL BE ACCOMPANIED BY SCATTERED
BRIEF PERIODS OF MVFR CIGS AND VSBYS. WINDS WILL BE LIGHT AND
VARIABLE THIS MORNING BECOMING SSW AT 10 TO 15 KTS THIS AFTERNOON
AND 5 TO 15 KTS TONIGHT.
OUTLOOK...
THU AND THU NGT...MVFR IN SHRA AND TSRA.
FRI...VFR BUT MVFR IN SCATTERED SHRA/TSRA MAINLY SOUTH.
SAT AND SUN...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...CMG/PVN
NEAR TERM...CMG/PVN
SHORT TERM...CMG
LONG TERM...HEDEN
AVIATION...MSE/TAC
AREA FORECAST DISCUSSION
NWS RALEIGH NC
750 PM EDT THU AUG 8 2013
.SYNOPSIS...
AN AREA OF HIGH PRESSURE ANCHORED OFFSHORE WILL RESULT IN A MOIST
SOUTHERLY FLOW ACROSS THE CAROLINAS THROUGH FRIDAY. A WEAK COLD
FRONT WILL APPROACH THE REGION FROM THE NORTH OVER THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 200 PM THURSDAY...
A WEAK WEST-EAST OR WSW-ENE ORIENTED UPPER LEVEL RIDGE ACROSS THE
SOUTH-CENTRAL AND SOUTHEAST CONUS WILL REMAIN IN PLACE THROUGH
TONIGHT...WITH THE PRIMARY BELT OF WESTERLIES LOCATED ACROSS THE
NORTHERN TIER OF THE CONUS (I.E. GREAT LAKES). WEAK WSW FLOW ALOFT
WILL PREVAIL ACROSS THE CAROLINAS. SOUTHERLY LOW-LEVEL RETURN FLOW
WILL PERSIST ACROSS THE REGION...ON THE WESTERN PERIPHERY OF A BROAD
SFC-H85 RIDGE CENTERED OFFSHORE IN THE ATLANTIC. LOW-LEVEL FLOW IS
PROGGED TO STRENGTHEN FROM 5-10 KT EARLY THIS AFTERNOON TO 15-25 KT
TONIGHT AS A POTENT UPPER LEVEL LOW IN ONTARIO PROGRESSES EAST
TOWARD QUEBEC AND AN ATTENDANT LOW-LEVEL TROUGH PROGRESSES INTO THE
OH VALLEY AND MID-ATLANTIC.
THIS AFTERNOON THROUGH MIDNIGHT:
ISOLD SHOWERS DEVELOPED IN THE FOOTHILLS AND FAR WESTERN PIEDMONT
THIS MORNING AND HAVE PERSISTED THROUGH EARLY THIS AFTERNOON. THIS
ACTIVITY IS ASSOCIATED WITH WEAK H85 CONFLUENCE IN THE PRESENCE OF
MARGINAL DIURNAL DESTABILIZATION AND DEEP MOISTURE (PWAT ~2.00").
THIS ACTIVITY MAY ALSO BE AIDED BY A VERY SUBTLE SMALL AMPLITUDE
DISTURBANCE EMBEDDED WITHIN WEAK WSW FLOW ALOFT OVER UPSTATE SC AND
SOUTHWEST NC. RAP GUIDANCE SUGGESTS THAT THE ZONE OF WEAK H85
CONFLUENCE ACTING AS A FOCUS WILL SHIFT EAST OF THE I-77 CORRIDOR
INTO THE FAR WESTERN PIEDMONT LATE THIS AFT/EVE...AND PROBABILITIES
FOR ISOLD TO SCT SHOWER ACTIVITY SHOULD ACCORDINGLY INCREASE
(40-50%) IN THE TRIAD AND W/SW PIEDMONT. ACTIVITY SHOULD PEAK IN
COVERAGE/INTENSITY BETWEEN 20-00Z WHEN DIURNAL DESTABILIZATION WILL
BE MAXIMIZED WITH MLCAPE VALUES OF 500-1000 J/KG...FOLLOWED BY
DECREASING COVERAGE/ INTENSITY THEREAFTER IN ASSOC/W THE ONSET OF
NOCTURNAL STABILIZATION. AN ISOLD THUNDERSTORM CANNOT BE RULED
OUT...THOUGH MARGINAL MLCAPE...WEAK MID-LEVEL LAPSE RATES AND WEAK
OVERALL FORCING MAY ULTIMATELY SERVE AS A LIMITING FACTOR W/REGARD
TO LIGHTNING. ALONG AND EAST OF THE HWY 1 CORRIDOR...STRONGER
INSOLATION WILL RESULT IN BETTER INSTABILITY WITH MLCAPE VALUES OF
1000-1500 J/KG EXPECTED. ALTHOUGH A WHOLESALE LACK OF FORCING MAY
LARGELY PRECLUDE CONVECTIVE DEVELOPMENT ALONG/EAST OF HWY 1...DEEP
MOISTURE...SEASONABLE DIURNAL DESTABILIZATION AND LITTLE OR NO CIN
SHOULD AT LEAST ALLOW FOR VERY ISOLD DEVELOPMENT...AND WILL INDICATE
A SLIGHT CHANCE (20%) OF SHOWERS IN THAT AREA PRIOR TO SUNSET.
OUTSIDE OF SOUTHERN SAMPSON COUNTY...ANTICIPATE LITTLE INFLUENCE
FROM THE SEABREEZE GIVEN LOW-LEVEL FLOW BECOMING INCREASINGLY
PARALLEL TO THE COAST THIS AFT/EVE. EXPECT HIGHS TODAY RANGING FROM
87-91F ALONG/EAST OF HWY 1 TO 82-85F IN THE WESTERN PIEDMONT WHERE
MORE CLOUD COVER IS PRESENT AND ISOLD SHOWER ACTIVITY MORE LIKELY.
MIDNIGHT THROUGH SUNRISE FRI:
FORCING FOR ASCENT WILL LARGELY BE ABSENT OVERNIGHT GIVEN WEAK FLOW
ALOFT...UNIDIRECTIONAL (SW) LOW-LEVEL FLOW AND LITTLE OR NO WARM
ADVECTION. A FEW ISOLD SHOWERS OR SPRINKLES CANNOT BE RULED OUT
GIVEN SUCH DEEP MOISTURE (PWAT ~2.00")...MARGINAL MUCAPE ASSOC/W A
925 MB AIRMASS CHARACTERIZED BY A T/TD OF 22/19C AND A SMALL
POTENTIAL FOR SUBTLE DISTURBANCES ALOFT OR WEAK LOW-LEVEL
CONVERGENCE...PRIMARILY IN THE W/NW PIEDMONT. WILL INDICATE A SLIGHT
CHANCE OF SHOWERS IN THE TRIAD AND FAR WESTERN PIEDMONT. EXPECT
RELATIVELY WARM LOWS IN THE LOWER 70S. -VINCENT
&&
.SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/...
AS OF 315 PM THURSDAY...
WEAK RIDGING ALOFT WILL PERSIST ACROSS THE SOUTH-CENTRAL AND
SOUTHEAST CONUS FRI/FRI NIGHT...WITH THE PRIMARY BELT OF WESTERLIES
CONFINED TO THE FAR NORTHERN MID-ATLANTIC...GREAT LAKES...AND NEW
ENGLAND. DEEP MOISTURE WILL PERSIST OVER THE CAROLINAS WITH PWAT
VALUES IN VICINITY OF 2.00"...AND DIURNAL DESTABILIZATION WILL BE
SOMEWHAT TEMPERED BY THE EXPECTATION OF OCCASIONALLY BROKEN CLOUD
COVER AND VERY WEAK (NEAR MOIST-ADIABATIC) MID-LEVEL LAPSE RATES...
WITH MLCAPE VALUES GENERALLY 750-1500 J/KG...THOUGH 1500-2000 J/KG
WILL BE POSSIBLE IF INSOLATION REMAINS UNINHIBITED IN SOME AREAS.
LITTLE IF ANY DIRECT UPPER LEVEL FORCING WILL BE PRESENT OVER
CENTRAL NC ON FRI/FRI NIGHT GIVEN THAT THE REGION IS AT THE FAR
SOUTHERN FRINGE OF THE WESTERLIES. HOWEVER...AN UPPER LEVEL LOW OVER
ONTARIO THIS AFTERNOON WILL TRACK EAST INTO QUEBEC TONIGHT/FRI...AND
AN ATTENDANT LOW-LEVEL TROUGH /SFC COLD FRONT/ WILL PUSH EAST FROM
THE GREAT LAKES INTO NEW ENGLAND AND THE NORTHERN MID-ATLANTIC. AN
EXTENSION OF THIS LOW-LEVEL TROUGH IS EXPECTED TO STRETCH SOUTHWEST
INTO WEST/NW PORTIONS OF THE CAROLINAS LATE FRIDAY AFT/EVE AND
FRIDAY NIGHT...AND THIS WILL LIKELY SERVE AS AN EFFECTIVE FOCUS FOR
CONVECTIVE DEVELOPMENT GIVEN EXCELLENT DEEP-LAYER MOISTURE...
MODERATE INSTABILITY AROUND/SHORTLY AFTER PEAK HEATING AND AT LEAST
MARGINAL INSTABILITY PERSISTING OVERNIGHT. ANTICIPATE THAT THE
SEABREEZE WILL REMAIN PINNED SOUTHEAST OF CUMBERLAND/SAMPSON/WAYNE
COUNTIES FRIDAY AFT/EVE GIVEN 15-20 KT SW/WSW LOW-LEVEL FLOW THAT
WILL BE NEAR PARALLEL TO THE NC COAST...ESPECIALLY GIVEN HIGHS AT
LEAST SOMEWHAT TEMPERED BY CLOUD COVER AND A RESULTING WEAKER
LAND/WATER TEMPERATURE GRADIENT. WITH THE ABOVE IN MIND...WILL
INDICATE PRECIP CHANCES RANGING FROM 40-60% WEST OF HWY 1 FRIDAY
AFTERNOON THROUGH MIDNIGHT...AND SLIGHT TO LOW CHANCE (20-40%) EAST
OF HWY 1...LOWEST EAST OF I-95 AND SOUTH OF HWY 64. WILL INDICATE A
SLIGHT TO LOW CHANCE (20-30%) OF CONVECTION PERSISTING OVERNIGHT
GIVEN CONTINUED (ALBEIT WEAK) LOW-LEVEL CONVERGENCE...DEEP
MOISTURE...AND MARGINAL INSTABILITY...PRIMARILY ALONG AND NORTH OF
HWY 64 AS THE LOW-LEVEL TROUGH BECOMES INCREASINGLY WEST-EAST
ORIENTED AND APPROACHES THE NC/VA BORDER FROM THE NORTH. HIGHS
FRIDAY RANGING FROM THE MID/UPPER 80S TO LOWER 90S...DEPENDENT
PRIMARILY ON CLOUD COVER. LOWS FRI NIGHT LOWER/MID 70S. -VINCENT
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
AS OF 230 PM THURSDAY...
THIS WEEKEND...SURFACE HIGH OFFSHORE FLATTENS AND ALIGNS MORE
EAST-WEST ACROSS THE SOUTHERN GULF STATES. ENSUING WESTERLY FLOW
WILL SHARPEN LEE TROUGHING OVER CENTRAL NC...INTO WHICH A WEAK COLD
FRONT SAGGING SOUTH OUT OF THE OHIO VALLEY WILL MERGE SATURDAY
NIGHT. MEANWHILE...FLOW WILL REMAIN WEAK AND NEAR ZONAL ALOFT. LOW
LEVEL FORCING FROM THE TWO BOUNDARIES WILL BE SUFFICIENT FOR
DEVELOPMENT OF FAIRLY WIDESPREAD CONVECTION IN THE LATE DAY AS HIGHS
WILL BE WITHIN A COUPLE OF DEGREES EITHER SIDE OF 90. EXPECT THE
FRONT DROPPING SOUTH TO BE THE STRONGER OF THE TWO AND WILL HAVE
LIKELY POPS ACROSS THE NORTH TO CHANCE IN THE SOUTH.
WE WILL HAVE A CONTINUING CHANCE OF SHOWERS OVERNIGHT SATURDAY NIGHT
AS THE BOUNDARIES MERGE...WHILE SUNDAY SHOULD BE QUITE ACTIVE
CONVECTIVELY...50 POP NORTHWEST TO 70 SOUTHEAST...ESPECIALLY ACROSS
THE SOUTHERN TIER WHERE MODELS HINT THAT WE COULD SEE A WEAK SURFACE
WAVE DEVELOP ALONG THE FRONT. NOT SEEING MUCH COOL AIR ADVECTION OR
HEIGHT FALLS SUNDAY...BUT HEAVY CLOUDINESS AND PRECIP WILL HAMPER
THE DIURNAL CLIMB...WITH HIGHS IN THE MID AND UPPER 80S. -MLM
ON MONDAY MOSTLY ZONAL FLOW OVER THE EASTERN US WILL YIELD TO A
TROUGH DIGGING SOUTHWARD FROM NORTHERN ONTARIO. THIS TROUGH WILL
DOMINATE THE SENSIBLE WEATHER THROUGH MIDWEEK...WITH LOWER THAN
NORMAL HIGH TEMPERATURES AND AN ABOVE NORMAL CHANCE OF RAIN.
AN INITIAL STATIONARY SURFACE FRONT OVER CENTRAL NC ON MONDAY WILL
BE PUSHED TO THE SE BY A SECOND APPROACHING SURFACE FRONT ASSOCIATED
WITH THE DIGGING TROUGH AROUND TUESDAY NIGHT. BOTH GFS AND EURO
MODELS SHOW THIS GREAT LAKES TROUGH AXIS AMPLIFYING SOUTHWARD INTO
KY AND TN BY EARLY TUESDAY. THESE MODELS HAVE SOME DISAGREEMENT IN
HOW QUICKLY THIS TROUGH MIGRATES EASTWARD. THE EASTWARD TROUGH
MOVEMENT WILL DETERMINE WHEN AND WHERE THIS SECOND SURFACE FRONT
WILL SET UP OVER CENTRAL NC. BOTH THE EURO AND GFS PREDICT THIS
FRONT TO BECOME ZONALLY ORIENTED...THE GFS EXPECTS THE FRONT TO
STALL OUT AND REMAIN STATIONARY OVER CENTRAL NC THROUGH WEDNESDAY
AND THURSDAY AS SURFACE HIGH PRESSURE BUILDS TO THE NORTH...WHILE
THE EURO HAS THE FRONT SLOWLY PASS THROUGH CENTRAL NC THROUGH
TUESDAY AND TUESDAY NIGHT BEFORE STALLING OUT MUCH FARTHER TO THE
SOUTH ON THURSDAY MORNING. THE LOCATION OF THIS FRONT WILL HIGHLY
IMPACT WHERE THE GREATEST PRECIP CHANCES WILL BE...WHILE THE SURFACE
HIGH AND ASSOCIATED DRY AIR WILL PUSH HIGH TEMPERATURES TO BE LOWER
INTO THE MIDWEEK.
THEREFORE...WILL PREDICT AN ABOVE NORMAL CHANCE OF POPS ACROSS THE
FORECAST AREA FOR MONDAY AND TUESDAY ASSOCIATED WITH THE INITIAL
FRONT...FOR WEDNESDAY AND THURSDAY...WITH MODEL AGREEMENT THAT THE
SECOND FRONT WILL BE OVER CENTRAL NC...HIGHER POPS TO THE SE AS
DRIER AIR IS EXPECTED TO BUILD BEHIND THE FRONT TO THE FAR NW OF THE
FORECAST AREA. HIGHS UPPER 80S-LOW 90S FOR MONDAY, COOLING TO THE
MID 80S FOR TUESDAY AND WEDNESDAY BEFORE MAINLY LOWER 80S ON
THURSDAY. LOWS NEAR PERSISTENCE ON MONDAY NIGHT...UPPER 60S AND LOW
70S...DECREASING TO THE MID AND UPPER 60S FOR TUESDAY AND WEDNESDAY
NIGHT. -BAS
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
AS OF 740 PM THURSDAY...
24-HR TAF PERIOD:
VFR CONDITIONS WILL LARGELY PREVAIL THIS EVENING THROUGH 06Z
TONIGHT. HOWEVER... AN ISOLATED SHOWER OR TWO WILL BE POSSIBLE THIS
EVENING... WITH THE BEST CHANCE OF SHOWERS AND ACCOMPANYING SUB VFR
CONDITIONS AT KGSO/KINT. THUS... HAVE INCLUDED A TEMPO GROUP FOR
SHOWERS THERE THROUGH 02Z. OVERNIGHT...MVFR/IFR CEILINGS WILL BE
POSSIBLE AT ALL TERMINALS...THOUGH CONFIDENCE IS RELATIVELY LOW
W/REGARD TO THE TIMING AND COVERAGE OF SUB-VFR CEILINGS ASSOC/W WITH
POTENTIAL STRATUS DEVELOPMENT IN THE 08-14Z TIME FRAME. MVFR/IFR
(MAYBE EVEN LIFR) VISBYS IN FOG WILL ALSO BE POSSIBLE BETWEEN 08-12Z
AT THE FAY/RWI TERMINALS (SIMILAR TO PREVIOUS NIGHTS)...THOUGH THIS
WILL DEPEND ON THE AMOUNT OF MID LEVEL CLOUD COVER NOW MOVING INTO
THE REGION. A BETTER CHANCE FOR SHOWERS AND THUNDERSTORMS IS
EXPECTED FRIDAY AFTERNOON AS A LOW-LEVEL TROUGH DEVELOPS IN THE LEE
OF THE APPALACHIANS... WITH THE BEST CHANCE FOR SHOWERS AND/OR
STORMS AT KGSO/KINT. HOWEVER... CONFIDENCE IS NOT HIGH ENOUGH TO
INCLUDE IN THE TAFS AT THIS TIME. IN ADDITION... EXPECT
SOUTHWESTERLY WINDS TO INCREASE ON FRIDAY... WITH 10 TO 15 MPH
SUSTAIN... AND PERHAPS A FEW GUSTS IN THE AFTERNOON UP TO 20 MPH.
LOOKING AHEAD:
EXPECT AN ABOVE AVERAGE CHANCE FOR SHOWERS AND THUNDERSTORMS
(PRIMARILY AFTERNOON AND EVENING HOURS) SATURDAY THROUGH EARLY TO
MID NEXT WEEK AS A FRONT APPROACHES FROM THE NORTH AND THEN STALLS
OVER THE CAROLINAS/VA IN THE PRESENCE OF CYCLONIC FLOW ALOFT.
MORNING FOG OR STRATUS WILL ALSO BE POSSIBLE EACH DAY... PRIMARILY
IN THE 08-14Z TIME FRAME.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...VINCENT
SHORT TERM..VINCENT
LONG TERM...MLM/BAS
AVIATION...BSD/VINCENT
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
200 PM EDT WED AUG 7 2013
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO RIDGE INTO THE CAROLINAS FROM THE
NORTHEAST THEN MOVE OFFSHORE OVER THE NEXT SEVERAL DAYS. AS THE
RIDGE LOSES ITS GRIP ACROSS THE REGION THE WINDS WILL BECOME
SOUTHERLY ALLOWING THE RETURN OF WARMER AND MORE HUMID AIR INTO THE
CAROLINAS. A COLD FRONT WILL STALL NEAR OR JUST NORTH OF THE AREA
MONDAY THROUGH WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 2 PM WEDNESDAY...HIGH PRESSURE CONTINUES TO WEDGE IN FROM THE
NORTHEAST AND MID-LEVEL CLOUD COVER CONTINUES MAINLY WEST OF
INTERSTATE 95.
THE HIGH RESOLUTION NUMERICAL MODELS ARE HAVING A DIFFICULT TIME
OF PRODUCING ANY CONVECTION AND THE 15 UTC HRRR IS SHOWING
ISOLATED CONVECTION AT 17 UTC BUT IT IS SHORT LIVED AND MAINLY
WEST OF A ELIZABETHTOWN TO ANDREWS LINE. CURRENT RADAR IS SHOWING
ONE POSSIBLE CONVECTIVE ELEMENT OVER CHESTERFIELD COUNTY. VISIBLE
SATELLITE IS SOME ENHANCED CUMULUS FIELDS OVER FLORENCE AND WESTERN
WILLIAMSBURG COUNTY.
A INTERESTING CYCLONIC FEATURE HAS BEEN OBSERVED IN THE RADAR THE
PAST HOUR OR SHOW. A FEW SHOWERS ARE WORKING THEIR WAY TOWARD THE
COAST BUT ARE SLOWLY DISSIPATING AS THEY APPROACH COAST. TODAY
WOULD BE A GOOD DAY FOR A LESS THAN 20% CHANCE. WILL CONTINUE TO
MONITOR AND MAY UP IT TO A 20% CHANCE ALONG INTERSTATE 95 AND THE
HORRY AND GEORGETOWN COAST ON THE NEXT UPDATE IF MORE SHOWERS
CONTINUE.
MOSTLY CLEAR SKIES ARE EXPECTED OVERNIGHT WITH TEMPERATURES
RANGING FROM NEAR 70 INLAND TO MID 70S ALONG THE BEACH. AS
MENTIONED IN LAST NIGHTS DISCUSSION WILL CONTINUE A MENTION OS
SHOWERS/ISOLATED THUNDERSTORMS OVER THE COASTAL WATERS WITH THE
SOUTHEAST FLOW. THEREFORE WILL STILL INCLUDE A 20 PERCENT POP FOR
THE BEACHES AROUND SUNRISE.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 2 PM WEDNESDAY...THE ATMOSPHERE WILL BE TRANSITIONING BACK TO
A MORE TYPICAL SUMMERTIME PATTERN WITH HIGH PRESSURE SETTING UP OFF
THE COAST ALLOWING FOR THE RETURN OF MORE HUMID CONDITIONS. AN H5
SUBTROPICAL RIDGE WILL BECOME PINCHED FROM THE SOUTHEAST U.S.
WESTWARD TO THE LOWER MS VALLEY AND TX...WITH A STRONG SHORTWAVE
PUSHING ACROSS SOUTHEAST CANADA AND WESTWARD MOVING H5 TROFS OVER
THE GULF OF MEXICO. DON/T THINK THE AIR-MASS WILL BECOME STRONGLY
CAPPED ACROSS THE FORECAST AREA AND WITH SUFFICIENT INSTABILITY
EXPECT WIDELY SCATTERED SHOWERS/TSTMS EACH DAY. THE SEA BREEZE FRONT
WILL BE THE PRIMARY LIFTING MECHANISM...MORE-SO IN THE AFTERNOON AND
EARLY EVENING. MAX/MIN TEMPS WILL BE AT OR ABOVE CLIMO EACH PERIOD.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 2 PM WEDNESDAY...ELONGATED MID LEVEL RIDGE WILL START TO BREAK
DOWN EARLY NEXT WEEK WITH LONGWAVE 5H TROUGH SETTING UP OVER THE
EAST COAST BY THE END OF THE PERIOD. THE PERIOD WILL START OFF WARM
AND RELATIVELY DRY...HIGHS IN THE LOW TO MID 90S AND LOWS IN THE LOW
TO MID 70S WITH SLIGHT CHC TO LOW CHC POP. CONVECTION IS LIKELY TO
BE DIURNAL IN NATURE AND ASSOCIATED WITH THE SEA BREEZE AND PIEDMONT
TROUGH. BREAK DOWN OF THE RIDGE AND RETREATING BERMUDA HIGH ALLOWS A
COLD FRONT TO DROP IN FROM THE NORTHWEST ON MON. MID LEVEL TROUGH
AXIS NEVER MOVES OFF THE COAST AND THE FRONT ENDS UP LAYING PARALLEL
TO THE STEERING FLOW. THIS WILL KEEP THE FRONT STALLED IN THE AREA
THROUGH WED. ABUNDANT DEEP MOISTURE IN THE PRESENCE OF THE
BOUNDARY...ALONG WITH OCCASIONAL SHORTWAVES PASSING OVERHEAD IN
SOUTHEAST FLOW WILL ELEVATE POP CHANCES FOR SECOND HALF OF THE
PERIOD. WILL KEEP POP IN CHC CAT BUT INCREASE TO 40-50 ALONG WITH
LOWERING HIGHS. LOWS WILL LIKELY REMAIN IN THE LOW TO MID 70S AS
COOLER AIR REMAINS TRAPPED NORTHWEST OF THE REGION AND CLOUD COVER
WILL LINGER. THINK COVERAGE OF PRECIP WILL DECREASE OVERNIGHT BUT
SHOWERS ARE LIKELY TO LINGER OVERNIGHT SO WILL MAINTAIN LOW CHC POP.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 18Z...ANOTHER DAY WITH MAINLY MID AND HIGH CLOUDS. A WEAK
SHORT WAVE OVER GEORGIA WILL SKIRT THE REGION AND WEAKEN AS IT
APPROACHES. AN ISOLATED SHOWER IS POSSIBLE...BUT UNLIKELY.
PREDOMINATELY SOUTHEAST FLOW WILL OCCUR THROUGH THE AFTERNOON
HOURS...DIMINISHING TONIGHT.
OVERNIGHT...MODELS ARE PRETTY AGGRESSIVE WITH BRINGING IN LIFR
FOG/STRATUS INLAND. ONLY MODERATE CONFIDENCE WITH THIS
SCENARIO...GIVEN A POSSIBILITY OF A VARIETY OF LAYERS OF CLOUDS
DEBRIS FROM THE WEAKENING SHORT WAVE.
THURSDAY...BECOMING VFR BY 13Z OR SO. WINDS WILL BE LIGHT...
SWINGING TO THE SOUTHWEST AS HIGH PRESSURE SHIFTS A BIT MORE
OFFSHORE.
EXTENDED OUTLOOK...ISOLATED AFTERNOON SHOWERS AND THUNDERSTORMS
POSSIBLE THURSDAY THROUGH SATURDAY...BECOMING SCATTERED SUNDAY AND
MONDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 2 PM WEDNESDAY...WINDS ARE NOW LIGHT FROM THE EAST AT 10 KNOTS
WITH SEAS RUNNING AROUND 2 FEET. WITH THE SOUTHEASTERLY FLOW THERE
HAS BEEN A SLIGHT INCREASE IN SHOWERS OVER THE WATER AS A SMALL
CYCLONIC FEATURE HAS BEEN OBSERVED ON RADAR THE PAST COUPLE OF
HOURS. WILL INCLUDE A SLIGHT CHANCE OF SHOWERS AS THEY PUSH TOWARDS
THE COAST.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 2 PM WEDNESDAY...HIGH PRESSURE WILL PRESIDE OFFSHORE RESULTING
IN SOUTHERLY FLOW ACROSS THE COASTAL WATERS DURING THE SHORT TERM
PERIOD. THE PRESSURE GRADIENT WILL LIKELY SUPPORT WINDS IN THE 10-15
KT RANGE...WITH SOME ENHANCEMENT EACH DAY FROM THE SEA BREEZE
CIRCULATION. SEAS WILL LIKELY AVERAGE 3 FT AWAY FROM THE COAST
THURSDAY AND 3-4 FT BY FRIDAY AFTERNOON...WITH HIGHER FREQUENCY
WAVES DOMINATING THE WAVE SPECTRUM.
LONG TERM /SATURDAY THROUGH MONDAY/...
AS OF 2 PM WEDNESDAY...BERMUDA HIGH AND PIEDMONT TROUGH WILL
MAINTAIN SOUTH TO SOUTHWEST FLOW OVER THE WATERS THROUGH THE PERIOD.
RELATIVELY WEAK GRADIENT WILL KEEP SPEEDS IN THE 10 TO 15 KT RANGE
WITH HIGHEST VALUES IN THE AFTERNOON/EVENING. SPEEDS MAY INCREASE A
LITTLE LATE IN THE PERIOD AS COLD FRONT DROPS IN FROM THE NORTHWEST
AND PINCHES GRADIENT. SEAS OF 2 TO 4 FT WILL BE A COMBINATION OF
DOMINANT SOUTHERLY WIND WAVE AND EAST TO SOUTHEAST SWELL.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...DRH
SHORT TERM...SRP
LONG TERM...III
AVIATION...DL/DRH
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
127 PM EDT WED AUG 7 2013
.SYNOPSIS...
HIGH PRESSURE SOUTH OF NOVA SCOTIA WILL MOVE FARTHER OFFSHORE OVER
THE NEXT SEVERAL DAYS. A RIDGE AXIS EXTENDING SOUTHWESTWARD INTO
NORTH CAROLINA WILL FINALLY DISSIPATE THURSDAY...ALLOWING WINDS TO
VEER MORE SOUTHERLY. THIS WILL ALLOW FOR WARMER AND MORE HUMID AIR
TO SPREAD INTO THE CAROLINAS...WITH INCREASING CHANCES OF SHOWERS
AND THUNDERSTORMS. A COLD FRONT WILL STALL NEAR OR JUST NORTH OF THE
AREA MONDAY AND TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 115 PM WEDNESDAY...HIGH PRESSURE CONTINUES TO WEDGE IN FROM THE
NORTHEAST AND MID-LEVEL CLOUD COVER CONTINUES MAINLY WEST OF
INTERSTATE 95.
THE HIGH RESOLUTION NUMERICAL MODELS ARE HAVING A DIFFICULT TIME
OF PRODUCING ANY CONVECTION AND THE 15 UTC HRRR IS SHOWING
ISOLATED CONVECTION AT 17 UTC BUT IT IS SHORT LIVED AND MAINLY
WEST OF A ELIZABETHTOWN TO ANDREWS LINE. CURRENT RADAR IS SHOWING
ONE POSSIBLE CONVECTIVE ELEMENT OVER CHESTERFIELD COUNTY. VISIBLE
SATELLITE IS SOME ENHANCED CUMULUS FIELDS OVER FLORENCE AND WESTERN
WILLIAMSBURG COUNTY.
A INTERESTING CYCLONIC FEATURE HAS BEEN OBSERVED IN THE RADAR THE
PAST HOUR OR SHOW. A FEW SHOWERS ARE WORKING THEIR WAY TOWARD THE
COAST BUT ARE SLOWLY DISSIPATING AS THEY APPROACH COAST. TODAY
WOULD BE A GOOD DAY FOR A LESS THAN 20% CHANCE. WILL CONTINUE TO
MONITOR AND MAY UP IT TO A 20% CHANCE ALONG INTERSTATE 95 AND THE
HORRY AND GEORGETOWN COAST ON THE NEXT UPDATE IF MORE SHOWERS
CONTINUE.
MOSTLY CLEAR SKIES ARE EXPECTED OVERNIGHT WITH TEMPERATURES
RANGING FROM NEAR 70 INLAND TO MID 70S ALONG THE BEACH. AS
MENTIONED IN LAST NIGHTS DISCUSSION WILL CONTINUE A MENTION OS
SHOWERS/ISOLATED THUNDERSTORMS OVER THE COASTAL WATERS WITH THE
SOUTHEAST FLOW. THEREFORE WILL STILL INCLUDE A 20 PERCENT POP FOR
THE BEACHES AROUND SUNRISE.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 300 AM WEDNESDAY...TYPICAL SUMMERTIME PATTERN FOR THE SHORT
TERM FORECAST THROUGH THE PERIOD WITH MID LEVEL RIDGING WITH THE
SEA-BREEZE AND PIEDMONT TROUGH BEING THE CATALYST FOR CONVECTION. THE
CONVECTION WILL BE MORE WIDESPREAD DURING THE AFTERNOON AND EARLY
EVENING HOURS. I HAVE MADE SOME SUBTLE ADJUSTMENTS IN POPS MAINLY TO
MATCH ADJACENT OFFICES BETTER. NUMERICAL GUIDANCE YIELDS LITTLE
CHANCE WITH THE 0000 BULLETINS AND TEMPERATURE FORECAST REMAINS
UNCHANGED FOR THE MOST PART.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 300 AM WEDNESDAY...MID LEVEL PATTERN SHOWS AN ELONGATED RIDGE
ACROSS THE SOUTHERN U.S. SHIFTING MORE WESTWARD THROUGH THE
PERIOD AS DECENT EAST COAST TROUGHING DEVELOPS ACROSS THE OHIO
VALLEY. AT THE SURFACE THE PERSISTENT BERMUDA RIDGE SLOWLY GIVES
WAY TO A FRONT DROPPING SOUTH WITH THE AFOREMENTIONED TROUGH. THIS
FEATURE WILL PROVIDE A FOCUS FOR CONVECTION/POPS SATURDAY THROUGH
TUESDAY. DON/T SEE ANY REASON TO GO ABOVE CHANCE POPS AT THIS TIME
BUT AS WE DRAW CLOSER THERE WILL ALMOST CERTAINLY BE PERIODS WHERE
AT LEAST LIKELY POPS WILL BE WARRANTED. TEMPERATURE GUIDANCE HAS
TAKEN A JOG TO WARMER NUMBERS AS HAS THE OFFICIAL FORECAST.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 18Z...ANOTHER DAY WITH MAINLY MID AND HIGH CLOUDS. A WEAK
SHORT WAVE OVER GEORGIA WILL SKIRT THE REGION AND WEAKEN AS IT
APPROACHES. AN ISOLATED SHOWER IS POSSIBLE...BUT UNLIKELY.
PREDOMINATELY SOUTHEAST FLOW WILL OCCUR THROUGH THE AFTERNOON
HOURS...DIMINISHING TONIGHT.
OVERNIGHT...MODELS ARE PRETTY AGGRESSIVE WITH BRINGING IN LIFR
FOG/STRATUS INLAND. ONLY MODERATE CONFIDENCE WITH THIS
SCENARIO...GIVEN A POSSIBILITY OF A VARIETY OF LAYERS OF CLOUDS
DEBRIS FROM THE WEAKENING SHORT WAVE.
THURSDAY...BECOMING VFR BY 13Z OR SO. WINDS WILL BE LIGHT...SWINGING
TO THE SOUTHWEST AS HIGH PRESSURE SHIFTS A BIT MORE OFFSHORE.
EXTENDED OUTLOOK...ISOLATED AFTERNOON SHOWERS AND THUNDERSTORMS
POSSIBLE THURSDAY THROUGH SATURDAY...BECOMING SCATTERED SUNDAY AND
MONDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 115 PM WEDNESDAY...WINDS ARE NOW LIGHT FROM THE EAST AT 10
KNOTS WITH SEAS RUNNING AROUND 2 FEET. WITH THE SOUTHEASTERLY FLOW
THERE HAS BEEN A SLIGHT INCREASE IN SHOWERS OVER THE WATER AS A
SMALL CYCLONIC FEATURE HAS BEEN OBSERVED ON RADAR THE PAST COUPLE
OF HOURS. WILL INCLUDE A SLIGHT CHANCE OF SHOWERS AS THEY PUSH
TOWARDS THE COAST.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 300 AM WEDNESDAY...WIND DIRECTIONS WILL BE A ISSUE AT LEAST
EARLY IN THE PERIOD AS A WEAK COASTAL TROUGH ALLOWS FOR SOUTHEAST
WINDS MOST OF THE DAY THURSDAY BEFORE A SOUTHWEST FLOW DEVELOPS.
THIS SOUTHWEST FLOW WILL CONTINUE THROUGH THE REMAINDER OF THE
PERIOD. A WEAK PRESSURE PATTERN WILL BE IN PLACE THROUGHOUT THE
PERIOD WITH WIND SPEEDS A COUPLE KNOTS EITHER SIDE OF TEN
KNOTS. WAVEWATCH AND SWAN SEAS ARE IN GOOD AGREEMENT ON
SIGNIFICANT SEAS OF 2-3 FEET.
LONG TERM /SATURDAY THROUGH SUNDAY/...
AS OF 300 AM WEDNESDAY...PERSISTENCE IS THE NAME OF THE GAME WITH
REGARDS TO THE COASTAL WATERS FORECAST FOR THE WEEKEND. EXPECT A
SOUTHWEST FLOW OF 10-15 KNOTS AS BERMUDA HIGH PRESSURE REMAINS THE
DOMINANT FEATURE. WAVEWATCH SEAS REMAIN IN A 2-4 FOOT RANGE.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...DRH
SHORT TERM...SHK
LONG TERM...SHK
AVIATION...SGL
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
117 PM EDT WED AUG 7 2013
.SYNOPSIS...
HIGH PRESSURE SOUTH OF NOVA SCOTIA WILL MOVE FARTHER OFFSHORE OVER
THE NEXT SEVERAL DAYS. A RIDGE AXIS EXTENDING SOUTHWESTWARD INTO
NORTH CAROLINA WILL FINALLY DISSIPATE THURSDAY...ALLOWING WINDS TO
VEER MORE SOUTHERLY. THIS WILL ALLOW FOR WARMER AND MORE HUMID AIR
TO SPREAD INTO THE CAROLINAS...WITH INCREASING CHANCES OF SHOWERS
AND THUNDERSTORMS. A COLD FRONT WILL STALL NEAR OR JUST NORTH OF THE
AREA MONDAY AND TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 115 PM WEDNESDAY...HIGH PRESSURE CONTINUES TO WEDGE IN FROM THE
NORTHEAST AND MID-LEVEL CLOUD COVER CONTINUES MAINLY WEST OF
INTERSTATE 95.
THE HIGH RESOLUTION NUMERICAL MODELS ARE HAVING A DIFFICULT TIME
OF PRODUCING ANY CONVECTION AND THE 15 UTC HRRR IS SHOWING
ISOLATED CONVECTION AT 17 UTC BUT IT IS SHORT LIVED AND MAINLY
WEST OF A ELIZABETHTOWN TO ANDREWS LINE. CURRENT RADAR IS SHOWING
ONE POSSIBLE CONVECTIVE ELEMENT OVER CHESTERFIELD COUNTY. VISIBLE
SATELLITE IS SOME ENHANCED CUMULUS FIELDS OVER FLORENCE AND WESTERN
WILLIAMSBURG COUNTY.
A INTERESTING CYCLONIC FEATURE HAS BEEN OBSERVED IN THE RADAR THE
PAST HOUR OR SHOW. A FEW SHOWERS ARE WORKING THEIR WAY TOWARD THE
COAST BUT ARE SLOWLY DISSIPATING AS THEY APPROACH COAST. TODAY
WOULD BE A GOOD DAY FOR A LESS THAN 20% CHANCE. WILL CONTINUE TO
MONITOR AND MAY UP IT TO A 20% CHANCE ALONG INTERSTATE 95 AND THE
HORRY AND GEORGETOWN COAST ON THE NEXT UPDATE IF MORE SHOWERS
CONTINUE.
MOSTLY CLEAR SKIES ARE EXPECTED OVERNIGHT WITH TEMPERATURES
RANGING FROM NEAR 70 INLAND TO MID 70S ALONG THE BEACH. AS
MENTIONED IN LAST NIGHTS DISCUSSION WILL CONTINUE A MENTION OS
SHOWERS/ISOLATED THUNDERSTORMS OVER THE COASTAL WATERS WITH THE
SOUTHEAST FLOW. THEREFORE WILL STILL INCLUDE A 20 PERCENT POP FOR
THE BEACHES AROUND SUNRISE.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 300 AM WEDNESDAY...TYPICAL SUMMERTIME PATTERN FOR THE SHORT
TERM FORECAST THROUGH THE PERIOD WITH MID LEVEL RIDGING WITH THE
SEA-BREEZE AND PIEDMONT TROUGH BEING THE CATALYST FOR CONVECTION. THE
CONVECTION WILL BE MORE WIDESPREAD DURING THE AFTERNOON AND EARLY
EVENING HOURS. I HAVE MADE SOME SUBTLE ADJUSTMENTS IN POPS MAINLY TO
MATCH ADJACENT OFFICES BETTER. NUMERICAL GUIDANCE YIELDS LITTLE
CHANCE WITH THE 0000 BULLETINS AND TEMPERATURE FORECAST REMAINS
UNCHANGED FOR THE MOST PART.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 300 AM WEDNESDAY...MID LEVEL PATTERN SHOWS AN ELONGATED RIDGE
ACROSS THE SOUTHERN U.S. SHIFTING MORE WESTWARD THROUGH THE
PERIOD AS DECENT EAST COAST TROUGHING DEVELOPS ACROSS THE OHIO
VALLEY. AT THE SURFACE THE PERSISTENT BERMUDA RIDGE SLOWLY GIVES
WAY TO A FRONT DROPPING SOUTH WITH THE AFOREMENTIONED TROUGH. THIS
FEATURE WILL PROVIDE A FOCUS FOR CONVECTION/POPS SATURDAY THROUGH
TUESDAY. DON/T SEE ANY REASON TO GO ABOVE CHANCE POPS AT THIS TIME
BUT AS WE DRAW CLOSER THERE WILL ALMOST CERTAINLY BE PERIODS WHERE
AT LEAST LIKELY POPS WILL BE WARRANTED. TEMPERATURE GUIDANCE HAS
TAKEN A JOG TO WARMER NUMBERS AS HAS THE OFFICIAL FORECAST.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 12Z...ANOTHER DAY WITH MAINLY MID AND HIGH CLOUDS. A WEAK
SHORT WAVE OVER GEORGIA WILL SKIRT THE REGION AND WEAKEN AS IT
APPROACHES. AN ISOLATED SHOWER IS POSSIBLE...BUT UNLIKELY.
PREDOMINATELY SOUTHEAST FLOW WILL OCCUR THROUGH THE AFTERNOON
HOURS...DIMINISHING TONIGHT. SOME LIGHT FOG IS POSSIBLE AFTER
08Z...MAINLY INLAND.
EXTENDED OUTLOOK...ISOLATED AFTERNOON SHOWERS AND THUNDERSTORMS
POSSIBLE WEDNESDAY THROUGH SUNDAY. OTHERWISE VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 115 PM WEDNESDAY...WINDS ARE NOW LIGHT FROM THE EAST AT 10
KNOTS WITH SEAS RUNNING AROUND 2 FEET. WITH THE SOUTHEASTERLY FLOW
THERE HAS BEEN A SLIGHT INCREASE IN SHOWERS OVER THE WATER AS A
SMALL CYCLONIC FEATURE HAS BEEN OBSERVED ON RADAR THE PAST COUPLE
OF HOURS. WILL INCLUDE A SLIGHT CHANCE OF SHOWERS AS THEY PUSH
TOWARDS THE COAST.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 300 AM WEDNESDAY...WIND DIRECTIONS WILL BE A ISSUE AT LEAST
EARLY IN THE PERIOD AS A WEAK COASTAL TROUGH ALLOWS FOR SOUTHEAST
WINDS MOST OF THE DAY THURSDAY BEFORE A SOUTHWEST FLOW DEVELOPS.
THIS SOUTHWEST FLOW WILL CONTINUE THROUGH THE REMAINDER OF THE
PERIOD. A WEAK PRESSURE PATTERN WILL BE IN PLACE THROUGHOUT THE
PERIOD WITH WIND SPEEDS A COUPLE KNOTS EITHER SIDE OF TEN
KNOTS. WAVEWATCH AND SWAN SEAS ARE IN GOOD AGREEMENT ON
SIGNIFICANT SEAS OF 2-3 FEET.
LONG TERM /SATURDAY THROUGH SUNDAY/...
AS OF 300 AM WEDNESDAY...PERSISTENCE IS THE NAME OF THE GAME WITH
REGARDS TO THE COASTAL WATERS FORECAST FOR THE WEEKEND. EXPECT A
SOUTHWEST FLOW OF 10-15 KNOTS AS BERMUDA HIGH PRESSURE REMAINS THE
DOMINANT FEATURE. WAVEWATCH SEAS REMAIN IN A 2-4 FOOT RANGE.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...DRH
SHORT TERM...SHK
LONG TERM...SHK
AVIATION...SGL
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1019 AM EDT WED AUG 7 2013
.SYNOPSIS...
HIGH PRESSURE SOUTH OF NOVA SCOTIA WILL MOVE FARTHER OFFSHORE OVER
THE NEXT SEVERAL DAYS. A RIDGE AXIS EXTENDING SOUTHWESTWARD INTO
NORTH CAROLINA WILL FINALLY DISSIPATE THURSDAY...ALLOWING WINDS TO
VEER MORE SOUTHERLY. THIS WILL ALLOW FOR WARMER AND MORE HUMID AIR
TO SPREAD INTO THE CAROLINAS...WITH INCREASING CHANCES OF SHOWERS
AND THUNDERSTORMS. A COLD FRONT WILL STALL NEAR OR JUST NORTH OF THE
AREA MONDAY AND TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1015 AM WEDNESDAY...HIGH PRESSURE CONTINUES TO WEDGE IN FROM
THE NORTHEAST AND MID-LEVEL CLOUD COVER CONTINUES MAINLY WEST OF
INTERSTATE 95. THE MORNING SOUNDINGS CONTINUE TO BE RATHER DRY
WITH THE NEWPORT SOUNDINGS PRECIPITABLE WATER JUST BE LOW THE 50TH
PERCENTILE.
THE HIGH RESOLUTION NUMERICAL MODELS ARE HAVING A DIFFICULT TIME
OF PRODUCING ANY CONVECTION AND THE 12 UTC HRRR IS SHOWING
ISOLATED CONVECTION AT 18 UTC BUT IT IS SHORT LIVED AND MAINLY
WEST OF A BURGAW TO ANDREWS LINE. AT THIS TIME CONFIDENCE IS LOW
OF A SLIGHT CHANCE OF CONVECTION SO WILL CONTINUE WITH THE CURRENT
FORECAST OF LESS THAN A 15 PERCENT CHANCE OF MEASURABLE
PRECIPITATION.
FROM PREVIOUS DISCUSSION...FOR TONIGHT MOSTLY CLEAR TO PARTLY CLOUDY
SKIES ARE EXPECTED WITH LOWS 69-74...WARMEST AT THE COAST. MODELS
ARE HINTING AT THE SOUTHEAST FLOW ALONG THE COAST POTENTIALLY
YIELDING SOME MARINE SHOWERS AFTER MIDNIGHT...SO I HAVE SHOWN A
TREND OF INCREASING POPS TOWARD SUNRISE THURSDAY AT THE BEACHES.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 300 AM WEDNESDAY...TYPICAL SUMMERTIME PATTERN FOR THE SHORT
TERM FORECAST THROUGH THE PERIOD WITH MID LEVEL RIDGING WITH THE
SEA-BREEZE AND PIEDMONT TROUGH BEING THE CATALYST FOR CONVECTION. THE
CONVECTION WILL BE MORE WIDESPREAD DURING THE AFTERNOON AND EARLY
EVENING HOURS. I HAVE MADE SOME SUBTLE ADJUSTMENTS IN POPS MAINLY TO
MATCH ADJACENT OFFICES BETTER. NUMERICAL GUIDANCE YIELDS LITTLE
CHANCE WITH THE 0000 BULLETINS AND TEMPERATURE FORECAST REMAINS
UNCHANGED FOR THE MOST PART.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 300 AM WEDNESDAY...MID LEVEL PATTERN SHOWS AN ELONGATED RIDGE
ACROSS THE SOUTHERN U.S. SHIFTING MORE WESTWARD THROUGH THE
PERIOD AS DECENT EAST COAST TROUGHING DEVELOPS ACROSS THE OHIO
VALLEY. AT THE SURFACE THE PERSISTENT BERMUDA RIDGE SLOWLY GIVES
WAY TO A FRONT DROPPING SOUTH WITH THE AFOREMENTIONED TROUGH. THIS
FEATURE WILL PROVIDE A FOCUS FOR CONVECTION/POPS SATURDAY THROUGH
TUESDAY. DON/T SEE ANY REASON TO GO ABOVE CHANCE POPS AT THIS TIME
BUT AS WE DRAW CLOSER THERE WILL ALMOST CERTAINLY BE PERIODS WHERE
AT LEAST LIKELY POPS WILL BE WARRANTED. TEMPERATURE GUIDANCE HAS
TAKEN A JOG TO WARMER NUMBERS AS HAS THE OFFICIAL FORECAST.
&&
.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
AS OF 12Z...ANOTHER DAY WITH MAINLY MID AND HIGH CLOUDS. A WEAK
SHORT WAVE OVER GEORGIA WILL SKIRT THE REGION AND WEAKEN AS IT
APPROACHES. AN ISOLATED SHOWER IS POSSIBLE...BUT UNLIKELY.
PREDOMINATELY SOUTHEAST FLOW WILL OCCUR THROUGH THE AFTERNOON
HOURS...DIMINISHING TONIGHT. SOME LIGHT FOG IS POSSIBLE AFTER
08Z...MAINLY INLAND.
EXTENDED OUTLOOK...ISOLATED AFTERNOON SHOWERS AND THUNDERSTORMS
POSSIBLE WEDNESDAY THROUGH SUNDAY. OTHERWISE VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1015 AM WEDNESDAY...NORTHEAST TO EAST WINDS THIS MORNING WITH
SPEEDS UNDER 10 KNOTS. THIS IS PRODUCING SEAS OF 2 TO 3 FEET.
WINDS ARE STILL ON TRACK TO VEER TO THE SOUTHEAST BY AFTERNOON.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 300 AM WEDNESDAY...WIND DIRECTIONS WILL BE A ISSUE AT LEAST
EARLY IN THE PERIOD AS A WEAK COASTAL TROUGH ALLOWS FOR SOUTHEAST
WINDS MOST OF THE DAY THURSDAY BEFORE A SOUTHWEST FLOW DEVELOPS.
THIS SOUTHWEST FLOW WILL CONTINUE THROUGH THE REMAINDER OF THE
PERIOD. A WEAK PRESSURE PATTERN WILL BE IN PLACE THROUGHOUT THE
PERIOD WITH WIND SPEEDS A COUPLE KNOTS EITHER SIDE OF TEN
KNOTS. WAVEWATCH AND SWAN SEAS ARE IN GOOD AGREEMENT ON
SIGNIFICANT SEAS OF 2-3 FEET.
LONG TERM /SATURDAY THROUGH SUNDAY/...
AS OF 300 AM WEDNESDAY...PERSISTENCE IS THE NAME OF THE GAME WITH
REGARDS TO THE COASTAL WATERS FORECAST FOR THE WEEKEND. EXPECT A
SOUTHWEST FLOW OF 10-15 KNOTS AS BERMUDA HIGH PRESSURE REMAINS THE
DOMINANT FEATURE. WAVEWATCH SEAS REMAIN IN A 2-4 FOOT RANGE.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...DRH
SHORT TERM...SHK
LONG TERM...SHK
AVIATION...SGL
AREA FORECAST DISCUSSION
NWS RALEIGH NC
740 AM EDT WED AUG 7 2013
.SYNOPSIS...
A MOIST SOUTHERLY RETURN FLOW WILL PREVAIL ACROSS THE REGION THROUGH
MID TO LATE WEEK...ON THE WESTERN PERIPHERY OF AN OFFSHORE RIDGE. A
COLD FRONT WILL MOVE INTO THE REGION BY THIS WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 255 AM WEDNESDAY...
PERSISTENCE WILL DOMINATE THE FORECAST TODAY AS SOUTHERLY LOW-LEVEL
FLOW CONTINUES BENEATH WEST-NORTHWESTERLY FLOW ALOFT. WEAK WARM
ADVECTION...MASS CONVERGENCE ALONG THE HIGHER TERRAIN... AND
MOISTURE POOLING OVER WESTERN WILL PROMOTE SCATTERED SHOWERS BY THIS
AFTERNOON. THE MOST RECENT HRRR RUN INDICATES SHOWERS NEAR THE TRIAD
BY AROUND NOON. DESPITE DEWPOINTS IN THE MID AND UPPER
60S...WIDESPREAD CLOUD COVER...BOTH AT LOW-LEVELS AND ALOFT...ALONG
WITH WEAK MID-LEVEL LAPSE RATES WILL KEEP MLCAPE AT 500 J/KG OR LESS
EAST OF THE MOUNTAINS. A WEAK UPPER DISTURBANCE LEFT OVER FROM
CONVECTION OVER MISSOURI IS CROSSING THE TN VALLEY THIS
MORNING...BUT THE MODEL CONSENSUS IS FOR THE DISTURBANCE TO CONTINUE
TO WEAKEN AS IT DROPS EAST-SOUTHEAST TOWARD GEORGIA AND SC.
THUS..THE CHANCE OF STORMS IS RATHER LOW TODAY. FORECAST SOUNDINGS
SUGGEST A FEW MORE BREAKS IN CLOUD COVER TODAY...BUT THE STRATUS
OVER THE WESTERN PIEDMONT THIS MORNING AND HIGH CLOUDS DRIFTING
OVERHEAD SHOULD HOLD TEMPS DOWN OVER THE WESTERN CWA...WITH 82-87 A
GOOD COMPROMISE OF STATISTICAL GUIDANCE.
TONIGHT
IN THE ABSENCE OF ANY SIGNIFICANT FORCING ALOFT...SHOWERS SHOULD BE
DIURNAL IN NATURE AND THE OVERNIGHT PERIOD DRY. STRATUS IS LIKELY
AGAIN OVER THE WESTERN PIEDMONT...WITH LOWS IN THE UPPER 60S TO
AROUND 70...WARMEST IN THE WEST.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/...
AS OF 300 AM WEDNESDAY...
THURSDAY AND THURSDAY NIGHT...
HEIGHTS ALOFT ARE EXPECTED TO RISE SLIGHTLY ON THURSDAY AS THE UPPER
RIDGE OVER THE SOUTHERN US BRIEFLY EXPANDS EASTWARD AND A SHORTWAVE
BEGINS TO DIVE SOUTH OUT OF CENTRAL CANADA. PW VALUES WILL CONTINUE
TO CREEP UP TO ABOVE 1.75`...BUT THE LACK OF FORCING
AND AFOREMENTIONED RIDGING ALOFT SHOULD KEEP CONVECTION CONFINED TO
THE SEABREEZE AND HIGHER TERRAIN. HIGHS IN THE MID TO UPPER 80S.
LOWS THURSDAY NIGHT AROUND 70. -SMITH
FOR FRIDAY/FRIDAY NIGHT: THE CANADIAN MIDLEVEL VORTEX MOVES FROM
CENTRAL ONTARIO OVER QUEBEC THROUGH FRI NIGHT WITH THE TRAILING
BROAD TROUGH AXIS SHIFTING ACROSS THE GREAT LAKES INTO THE
MIDATLANTIC AND NORTHEAST. THE ASSOCIATED SURFACE COLD FRONT BECOMES
MORE EAST-WEST ORIENTED TO OUR NORTH WHILE HEIGHTS ALOFT RISE
SLIGHTLY OVER NC. THE UPPER LEVEL ANTICYCLONE TO OUR SOUTH SHIFTS
EASTWARD... AND THE STRENGTHENING WESTERLY FLOW AT JET LEVEL INDUCES
INCREASING UPPER DIVERGENCE OVER VA INTO CENTRAL NC (ALTHOUGH MODELS
DIFFER ON THE DETAILS)... AND THE STRENGTHENING AND VEERING LOW
LEVEL FLOW (WITH THE 850 MB TROUGH PASSAGE) RESULTS IN STRENGTHENING
MOISTURE TRANSPORT PARTICULARLY OVER NORTH CENTRAL AND NORTHEAST NC
IN THE AFTERNOON THROUGH EVENING. MODERATE INSTABILITY (MLCAPE OF
1200-1800 J/KG) IS EXPECTED FRI AFTERNOON/EVENING BUT WITH POOR
DEEP-LAYER SHEAR UNDER 20 KTS FOR MUCH OF THE DAY...ALTHOUGH THIS
DOES IMPROVE SLIGHTLY OVERNIGHT AS MIDLEVEL WINDS STRENGTHEN NEAR
THE NC/VA BORDER... WHILE SOME WEAK ELEVATED INSTABILITY LINGERS.
GIVEN THIS COMBINATION OF INSTABILITY AND WEAK DYNAMIC FORCING FOR
ASCENT WITH HIGH PW AT OR ABOVE 2.0 INCHES... AT LEAST A 50%
COVERAGE OF SHOWERS/STORMS IS JUSTIFIED ACROSS THE WRN/NRN CWA WHERE
MOISTURE TRANSPORT IS HIGHEST ALONG THE LEE SURFACE TROUGH... WITH A
LITTLE LOWER CHANCE OVER THE SOUTHEAST CLOSER TO THE MIDLEVEL
ANTICYCLONE CENTER. HIGHS 88-92. RAIN CHANCES SHOULD WIND DOWN BY
LATE EVENING AS LOW LEVEL FLOW BECOMES MORE WESTERLY WITH DOWNSLOPE
DRYING AND INCREASING STABILITY AFTER SUNSET... BUT THE ANOMALOUSLY
HIGH MOISTURE CONTENT OF THE COLUMN SUPPORTS A CONTINUED THREAT OF
ISOLATED SHOWERS OVERNIGHT. LOWS 70-74.
FOR SATURDAY/SATURDAY NIGHT: THIS STILL LOOKS LIKE THE WETTEST DAY
OF THIS FORECAST. HEIGHTS ALOFT BEGIN TO FALL OVER THE APPALACHIANS
INTO CENTRAL NC AS ENERGY TRACKS INTO THE TROUGH BASE... FROM
ONTARIO ACROSS THE OH VALLEY... WHILE DEEP MOISTURE PERSISTS OVER
THE LINGERING LEE TROUGH OVER CENTRAL NC AHEAD OF THE APPROACHING
LARGE SCALE FRONTAL ZONE TO OUR NORTH AND NORTHWEST. THE INCREASING
DPVA... HIGH LOW-LEVEL THETA-E... HIGH PW... AND MODERATE
INSTABILITY SUPPORTS A 50-60% CHANCE OF SHOWERS/STORMS... HIGHEST IN
THE NW AND NORTHERN CWA WHERE UPPER DIVERGENCE WILL BE GREATEST IN
THE RIGHT ENTRANCE REGION OF THE 80-100 KT JET CORE OVER/OFF NEW
ENGLAND. HIGHS 88-93 AS THE ABOVE-NORMAL THICKNESSES ARE TEMPERED BY
ABUNDANT CLOUDINESS AND THE EARLY ONSET OF CONVECTION. LOWS AGAIN
70-74 WITH PLENTY OF CLOUDS AND A FEW RESIDUAL SHOWERS OVERNIGHT.
-GIH
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
AS OF 250 AM WEDNESDAY...
THE AMPLIFICATION OF THE EASTERN US TROUGH CONTINUES INTO EARLY NEXT
WEEK AS A SECONDARY VORTEX DROPS DOWN THROUGH ERN ONTARIO/JAMES BAY.
MODELS INDICATE THAT THE SURFACE FRONT WILL SINK SLOWLY SE INTO FAR
NRN AND WRN NC SUNDAY/SUNDAY NIGHT. WITH INCREASING DYNAMIC
FORCING... MODERATE AFTERNOON INSTABILITY (2000-2500 J/KG MAINLY
ALONG/EAST OF HIGHWAY 1)... AND CONTINUED HIGH MOISTURE THROUGH THE
COLUMN... HIGH PROBABILITIES OF SHOWERS/STORMS SHOULD EXTEND THROUGH
SUNDAY. THE GFS/ECMWF SWING THE MIDLEVEL LOW OVER SE ONTARIO AND SRN
QUEBEC/UPPER ST LAWRENCE... AMPLIFYING THE SOUTHERN PORTION OF THE
MEAN TROUGH SUFFICIENTLY SO AS TO NUDGE THE FRONT TO ERN/SRN NC FOR
MONDAY/TUESDAY. CONSIDERING THAT THE MODEL RUNS FROM A FEW DAYS AGO
WERE PUSHING THIS FRONT TO OUR SOUTH AS EARLY AS SUNDAY AND HAVE NOW
BACKED OFF ON THAT SCENARIO... AND CONSIDERING THAT TRUE COLD FRONT
PASSAGE THROUGH NC WITHOUT A STRONG AMPLIFYING TROUGH IS A RARITY...
I HAVE SOME RESERVATIONS ABOUT BRINGING IN A LOT OF STABLE OR
MARKEDLY COOLER AIR INTO THE NRN/WRN CWA. WILL HOLD ONTO DAILY
CHANCE POPS OVER THE ERN/SRN CWA... NEAR THE LIKELY POSITION OF THE
FRONTAL ZONE... WITH SLIGHTLY LOWER POPS (BUT NOT ZERO) OVER THE NW
BOTH MONDAY AND TUESDAY. THICKNESSES SHOULD DIP A BIT HEADING INTO
EARLY NEXT WEEK... SO EXPECT HIGHS TO TREND FROM AROUND 90 SUNDAY
INTO THE MID-UPPER 80S BY TUESDAY. LOWS IN THE UPPER 60S TO LOWER
70S... SLIPPING 2-3 DEGREES FROM SUNDAY TO TUESDAY. -GIH
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
AS OF 740 AM WEDNESDAY...
THE PATTERN OF A MOIST SOUTHERLY FLOW AND BETTER CHANCES OF SHOWERS
OVER THE WESTERN PIEDMONT WILL CONTINUE THROUGH THE TAF PERIOD.
CEILINGS HAVE BEEN HOVERING AROUND MVFR LEVELS IN THE TRIAD THIS
MORNING...BUT SHOULD IMPROVE TO VFR BY MID-MORNING. MOST
HI-RESOLUTION MODELS SHOW SHOWERS DEVELOPING TO THE SOUTH AND WEST
OF KGSO/KINT BY 16Z...LIKELY MOVING INTO THE VICINITY OF THOSE
TERMINALS THROUGHOUT THE AFTERNOON. WHILE A THUNDERSTORM IS
CERTAINLY POSSIBLE...THE CHANCE APPEARS TO BE RELATIVELY LOW TODAY.
MOST OF THE SHOWERS OR STORMS SHOULD THEN WEAKEN AND DISSIPATE AS
THEY MOVE EAST INTO A MORE STABLE ENVIRONMENT OVER THE PIEDMONT AND
COASTAL PLAIN. TONIGHT...STRATUS IS EXPECTED TO REDEVELOP
LATE...PRIMARILY OVER THE WESTERN PIEDMONT...WITH A BETTER CHANCE OF
LIMITED VSBYS AT EASTERN TERMINALS.
OUTLOOK...
MORNING STRATUS AND AFTERNOON SHOWERS/STORMS WILL BE POSSIBLE EACH
DAY FOR THE REMAINDER OF THE WEEK...ALTHOUGH THE COVERAGE OF SHOWERS
AND STORMS IS EXPECTED TO INCREASE FRIDAY AND SATURDAY AS A COLD
FRONT MOVES INTO THE REGION FROM THE NORTHWEST.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...SMITH
SHORT TERM..SMITH/HARTFIELD
LONG TERM...HARTFIELD
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
705 AM EDT WED AUG 7 2013
.SYNOPSIS...
HIGH PRESSURE SOUTH OF NOVA SCOTIA WILL MOVE FARTHER OFFSHORE OVER
THE NEXT SEVERAL DAYS. A RIDGE AXIS EXTENDING SOUTHWESTWARD INTO
NORTH CAROLINA WILL FINALLY DISSIPATE THURSDAY...ALLOWING WINDS TO
VEER MORE SOUTHERLY. THIS WILL ALLOW FOR WARMER AND MORE HUMID AIR
TO SPREAD INTO THE CAROLINAS...WITH INCREASING CHANCES OF SHOWERS
AND THUNDERSTORMS. A COLD FRONT WILL STALL NEAR OR JUST NORTH OF THE
AREA MONDAY AND TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM WEDNESDAY...06Z MODELS LOOK VERY SIMILAR TO THEIR 00Z
COUNTERPARTS. THE ONE TREND I DID NOTICE IS AN INCREASE IN MID-LEVEL
CLOUD COVER ACROSS MAINLY THE INTERIOR EASTERN CAROLINAS THROUGH
MOST OF THE AFTERNOON. THIS HAS LED ME TO CHANGE SKY COVER FORECASTS
TO "MOSTLY CLOUDY" ACROSS ALL OF THE INTERSTATE 95 CORRIDOR WITH A
ONE-DEGREE TWEAK DOWNWARD IN FORECAST HIGHS AT FLO/LBT/UDG. NO
SIGNIFICANT CHANGES HAVE BEEN MADE ALONG THE COAST. PREVIOUS
DISCUSSION FROM 300 AM FOLLOWS...
AFTER YESTERDAY`S FORECAST DEBACLE ALONG AND WEST OF THE INTERSTATE
95 CORRIDOR...I AM HOPING THIS IS A BETTER FORECAST FOR TODAY.
SURFACE HIGH PRESSURE IS DEPARTING THE COASTAL MID-ATLANTIC
REGION...BUT A RIDGE AXIS REMAINS ENTRENCHED ACROSS THE INTERIOR
CAROLINAS. EASTERLY FLOW ACROSS THE ATLANTIC IS GRADUALLY WARMING
AND MOISTENING AS THE SOURCE REGION FOR THE INCOMING STREAMLINES
SHIFTS TO BERMUDA INSTEAD OF EASTERN CANADA.
THE UPPER LEVEL PATTERN FEATURES A 500 MB RIDGE OVER EASTERN TEXAS
WITH A WEAKENING LONGWAVE TROUGH OVER THE EASTERN U.S. 500 MB
HEIGHTS SHOULD RISE BY ABOUT 20 METERS OVER THE CAROLINAS TODAY. ONE
POTENTIAL PROBLEM DESPITE THE BUILDING RIDGE IS A WEAK SHORTWAVE
TROUGH EMBEDDED IN THE WESTERLY UPPER LEVEL FLOW. THIS FEATURE IS
COLLOCATED WITH A CLUSTER OF THUNDERSTORMS IN NORTH GEORGIA EARLY
THIS MORNING...AND IS DEPICTED BETTER IN THE GFS THAN THE NAM. IT
SHOULD TRANSIT THE EASTERN CAROLINAS DURING THE LATE AFTERNOON
HOURS...WEAKENING ALONG THE COAST THIS EVENING AS A COL (WEAK WIND
REGION) DEVELOPS IN BETWEEN THE TEXAS AND BERMUDA RIDGES.
AT THE RISK OF MAKING THE SAME MISTAKE I DID YESTERDAY...I SEE A
VERY LOW RISK FOR SHOWERS TODAY GIVEN INSUFFICIENT MOISTURE AND WEAK
LAPSE RATES WITHIN THE LOWER TROPOSPHERE. FORECAST SOUNDINGS FROM
THE GFS...ECMWF AND RUC SHOW A CAPPED CONVECTIVE ENVIRONMENT. ONLY
THE NAM DEVELOPS ANY SUBSTANTIAL SURFACE-BASED OR ELEVATED
INSTABILITY TODAY (DUE TO SURFACE DEWPOINTS THAT LOOK TOO HIGH) BUT
THAT MODEL ALSO SHOWS INSUFFICIENT FORCING FOR SHOWERS. THE 200-300
MB JET STREAM IS NOW WELL NORTH AND EAST OF THE CAROLINAS...TAKING
ANY POTENTIAL UPPER DIVERGENT REGIONS OUT OF THE PICTURE LOCALLY.
SCATTERED MID-LEVEL CLOUDS COULD BECOME A LITTLE MORE SUBSTANTIAL AT
TIMES INLAND TODAY...BUT SHOULD NOT DO TOO MUCH TO HOLD TEMPERATURES
DOWN. HIGHS ARE EXPECTED TO REACH 87-88 INLAND WITH MID 80S NEAR THE
COAST.
FOR TONIGHT MOSTLY CLEAR TO PARTLY CLOUDY SKIES ARE EXPECTED WITH
LOWS 69-74...WARMEST AT THE COAST. MODELS ARE HINTING AT THE
SOUTHEAST FLOW ALONG THE COAST POTENTIALLY YIELDING SOME MARINE
SHOWERS AFTER MIDNIGHT...SO I HAVE SHOWN A TREND OF INCREASING POPS
TOWARD SUNRISE THURSDAY AT THE BEACHES.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 300 AM WEDNESDAY...TYPICAL SUMMERTIME PATTERN FOR THE SHORT
TERM FORECAST THROUGH THE PERIOD WITH MID LEVEL RIDGING WITH THE
SEABREEZE AND PIEDMONT TROUGH BEING THE CATALYST FOR CONVECTION. THE
CONVECTION WILL BE MORE WIDESPREAD DURING THE AFTERNOON AND EARLY
EVENING HOURS. I HAVE MADE SOME SUBTLE ADJUSTMENTS IN POPS MAINLY TO
MATCH ADJACENT OFFICES BETTER. NUMERICAL GUIDANCE YIELDS LITTLE
CHANCE WITH THE 0000 BULLETINS AND TEMPERATURE FORECAST REMAINS
UNCHANGED FOR THE MOST PART.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 300 AM WEDNESDAY...MID LEVEL PATTERN SHOWS AN ELONGATED RIDGE
ACROSS THE SOUTHERN U.S. SHIFTING MORE WESTWARD THROUGH THE
PERIOD AS DECENT EAST COAST TROUGHING DEVELOPS ACROSS THE OHIO
VALLEY. AT THE SURFACE THE PERSISTENT BERMUDA RIDGE SLOWLY GIVES
WAY TO A FRONT DROPPING SOUTH WITH THE AFOREMENTIONED TROUGH. THIS
FEATURE WILL PROVIDE A FOCUS FOR CONVECTION/POPS SATURDAY THROUGH
TUESDAY. DON/T SEE ANY REASON TO GO ABOVE CHANCE POPS AT THIS TIME
BUT AS WE DRAW CLOSER THERE WILL ALMOST CERTAINLY BE PERIODS WHERE
AT LEAST LIKELY POPS WILL BE WARRANTED. TEMPERATURE GUIDANCE HAS
TAKEN A JOG TO WARMER NUMBERS AS HAS THE OFFICIAL FORECAST.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
AS OF 12Z...ANOTHER DAY WITH MAINLY MID AND HIGH CLOUDS. A WEAK
SHORT WAVE OVER GEORGIA WILL SKIRT THE REGION AND WEAKEN AS IT
APPROACHES. AN ISOLATED SHOWER IS POSSIBLE...BUT UNLIKELY.
PREDOMINATELY SOUTHEAST FLOW WILL OCCUR THROUGH THE AFTERNOON
HOURS...DIMINISHING TONIGHT. SOME LIGHT FOG IS POSSIBLE AFTER
08Z...MAINLY INLAND.
EXTENDED OUTLOOK...ISOLATED AFTERNOON SHOWERS AND THUNDERSTORMS
POSSIBLE WEDNESDAY THROUGH SUNDAY. OTHERWISE VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM WEDNESDAY...THE ONLY CHANGE TO THE FORECAST WAS TO BACK
WIND DIRECTIONS BY 20-30 DEGREES FOR THE REMAINDER OF THE MORNING...
STILL VEERING SOUTHEASTERLY THIS AFTERNOON. WIND SPEEDS AND SEA
HEIGHTS STILL LOOK GOOD. PREVIOUS DISCUSSION FROM 300 AM FOLLOWS...
HIGH PRESSURE OFF THE MID-ATLANTIC COAST
SHOULD MOVE FARTHER OUT TO SEA TODAY...BUT A SURFACE RIDGE AXIS WILL
REMAIN PARKED ACROSS INTERIOR NORTH CAROLINA. UNTIL THIS RIDGE AXIS
BREAKS DOWN DURING THE DAY THURSDAY OUR WIND DIRECTIONS WILL NOT
VEER SIGNIFICANTLY FROM EAST-SOUTHEAST. MODELS ARE IN EXCELLENT
AGREEMENT WITH WIND SPEEDS...EXPECTED TO AVERAGE 10 KNOTS BOTH TODAY
AND TONIGHT. SEAS CURRENTLY AROUND 2 FT SHOULD CHANGE VERY LITTLE
THROUGH TONIGHT WITH VIRTUALLY NO SWELL ENERGY VISIBLE ON SPECTRAL
WAVE PLOTS FROM THE FRYING PAN SHOALS BUOY.
SHOWER CHANCES WILL REMAIN VERY LOW THROUGH THIS EVENING...BUT MAY
INCREASE A LITTLE AFTER MIDNIGHT TONIGHT...ESPECIALLY OFFSHORE.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 300 AM WEDNESDAY...WIND DIRECTIONS WILL BE A ISSUE AT LEAST
EARLY IN THE PERIOD AS A WEAK COASTAL TROUGH ALLOWS FOR SOUTHEAST
WINDS MOST OF THE DAY THURSDAY BEFORE A SOUTHWEST FLOW DEVELOPS.
THIS SOUTHWEST FLOW WILL CONTINUE THROUGH THE REMAINDER OF THE
PERIOD. A WEAK PRESSURE PATTERN WILL BE IN PLACE THROUGHOUT THE
PERIOD WITH WIND SPEEDS A COUPLE KNOTS EITHER SIDE OF TEN
KNOTS.WAVEWATCH AND SWAN SEAS ARE IN GOOD AGREEMENT ON SIGNIFICANT
SEAS OF 2-3 FEET.
LONG TERM /SATURDAY THROUGH SUNDAY/...
AS OF 300 AM WEDNESDAY...PERSISTENCE IS THE NAME OF THE GAME WITH
REGARDS TO THE COASTAL WATERS FORECAST FOR THE WEEKEND. EXPECT A
SOUTHWEST FLOW OF 10-15 KNOTS AS BERMUDA HIGH PRESSURE REMAINS THE
DOMINANT FEATURE. WAVEWATCH SEAS REMAIN IN A 2-4 FOOT RANGE.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...TRA
SHORT TERM...SHK
LONG TERM...SHK
AVIATION...43
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
635 AM EDT WED AUG 7 2013
.SYNOPSIS...
HIGH PRESSURE SOUTH OF NOVA SCOTIA WILL MOVE FARTHER OFFSHORE OVER
THE NEXT SEVERAL DAYS. A RIDGE AXIS EXTENDING SOUTHWESTWARD INTO
NORTH CAROLINA WILL FINALLY DISSIPATE THURSDAY...ALLOWING WINDS TO
VEER MORE SOUTHERLY. THIS WILL ALLOW FOR WARMER AND MORE HUMID AIR
TO SPREAD INTO THE CAROLINAS...WITH INCREASING CHANCES OF SHOWERS
AND THUNDERSTORMS. A COLD FRONT WILL STALL NEAR OR JUST NORTH OF THE
AREA MONDAY AND TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM WEDNESDAY...06Z MODELS LOOK VERY SIMILAR TO THEIR 00Z
COUNTERPARTS. THE ONE TREND I DID NOTICE IS AN INCREASE IN MID-LEVEL
CLOUD COVER ACROSS MAINLY THE INTERIOR EASTERN CAROLINAS THROUGH
MOST OF THE AFTERNOON. THIS HAS LED ME TO CHANGE SKY COVER FORECASTS
TO "MOSTLY CLOUDY" ACROSS ALL OF THE INTERSTATE 95 CORRIDOR WITH A
ONE-DEGREE TWEAK DOWNWARD IN FORECAST HIGHS AT FLO/LBT/UDG. NO
SIGNIFICANT CHANGES HAVE BEEN MADE ALONG THE COAST. PREVIOUS
DISCUSSION FROM 300 AM FOLLOWS...
AFTER YESTERDAY`S FORECAST DEBACLE ALONG AND WEST OF THE INTERSTATE
95 CORRIDOR...I AM HOPING THIS IS A BETTER FORECAST FOR TODAY.
SURFACE HIGH PRESSURE IS DEPARTING THE COASTAL MID-ATLANTIC
REGION...BUT A RIDGE AXIS REMAINS ENTRENCHED ACROSS THE INTERIOR
CAROLINAS. EASTERLY FLOW ACROSS THE ATLANTIC IS GRADUALLY WARMING
AND MOISTENING AS THE SOURCE REGION FOR THE INCOMING STREAMLINES
SHIFTS TO BERMUDA INSTEAD OF EASTERN CANADA.
THE UPPER LEVEL PATTERN FEATURES A 500 MB RIDGE OVER EASTERN TEXAS
WITH A WEAKENING LONGWAVE TROUGH OVER THE EASTERN U.S. 500 MB
HEIGHTS SHOULD RISE BY ABOUT 20 METERS OVER THE CAROLINAS TODAY. ONE
POTENTIAL PROBLEM DESPITE THE BUILDING RIDGE IS A WEAK SHORTWAVE
TROUGH EMBEDDED IN THE WESTERLY UPPER LEVEL FLOW. THIS FEATURE IS
COLLOCATED WITH A CLUSTER OF THUNDERSTORMS IN NORTH GEORGIA EARLY
THIS MORNING...AND IS DEPICTED BETTER IN THE GFS THAN THE NAM. IT
SHOULD TRANSIT THE EASTERN CAROLINAS DURING THE LATE AFTERNOON
HOURS...WEAKENING ALONG THE COAST THIS EVENING AS A COL (WEAK WIND
REGION) DEVELOPS IN BETWEEN THE TEXAS AND BERMUDA RIDGES.
AT THE RISK OF MAKING THE SAME MISTAKE I DID YESTERDAY...I SEE A
VERY LOW RISK FOR SHOWERS TODAY GIVEN INSUFFICIENT MOISTURE AND WEAK
LAPSE RATES WITHIN THE LOWER TROPOSPHERE. FORECAST SOUNDINGS FROM
THE GFS...ECMWF AND RUC SHOW A CAPPED CONVECTIVE ENVIRONMENT. ONLY
THE NAM DEVELOPS ANY SUBSTANTIAL SURFACE-BASED OR ELEVATED
INSTABILITY TODAY (DUE TO SURFACE DEWPOINTS THAT LOOK TOO HIGH) BUT
THAT MODEL ALSO SHOWS INSUFFICIENT FORCING FOR SHOWERS. THE 200-300
MB JET STREAM IS NOW WELL NORTH AND EAST OF THE CAROLINAS...TAKING
ANY POTENTIAL UPPER DIVERGENT REGIONS OUT OF THE PICTURE LOCALLY.
SCATTERED MID-LEVEL CLOUDS COULD BECOME A LITTLE MORE SUBSTANTIAL AT
TIMES INLAND TODAY...BUT SHOULD NOT DO TOO MUCH TO HOLD TEMPERATURES
DOWN. HIGHS ARE EXPECTED TO REACH 87-88 INLAND WITH MID 80S NEAR THE
COAST.
FOR TONIGHT MOSTLY CLEAR TO PARTLY CLOUDY SKIES ARE EXPECTED WITH
LOWS 69-74...WARMEST AT THE COAST. MODELS ARE HINTING AT THE
SOUTHEAST FLOW ALONG THE COAST POTENTIALLY YIELDING SOME MARINE
SHOWERS AFTER MIDNIGHT...SO I HAVE SHOWN A TREND OF INCREASING POPS
TOWARD SUNRISE THURSDAY AT THE BEACHES.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 300 AM WEDNESDAY...TYPICAL SUMMERTIME PATTERN FOR THE SHORT
TERM FORECAST THROUGH THE PERIOD WITH MID LEVEL RIDGING WITH THE
SEABREEZE AND PIEDMONT TROUGH BEING THE CATALYST FOR CONVECTION. THE
CONVECTION WILL BE MORE WIDESPREAD DURING THE AFTERNOON AND EARLY
EVENING HOURS. I HAVE MADE SOME SUBTLE ADJUSTMENTS IN POPS MAINLY TO
MATCH ADJACENT OFFICES BETTER. NUMERICAL GUIDANCE YIELDS LITTLE
CHANCE WITH THE 0000 BULLETINS AND TEMPERATURE FORECAST REMAINS
UNCHANGED FOR THE MOST PART.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 300 AM WEDNESDAY...MID LEVEL PATTERN SHOWS AN ELONGATED RIDGE
ACROSS THE SOUTHERN U.S. SHIFTING MORE WESTWARD THROUGH THE
PERIOD AS DECENT EAST COAST TROUGHING DEVELOPS ACROSS THE OHIO
VALLEY. AT THE SURFACE THE PERSISTENT BERMUDA RIDGE SLOWLY GIVES
WAY TO A FRONT DROPPING SOUTH WITH THE AFOREMENTIONED TROUGH. THIS
FEATURE WILL PROVIDE A FOCUS FOR CONVECTION/POPS SATURDAY THROUGH
TUESDAY. DON/T SEE ANY REASON TO GO ABOVE CHANCE POPS AT THIS TIME
BUT AS WE DRAW CLOSER THERE WILL ALMOST CERTAINLY BE PERIODS WHERE
AT LEAST LIKELY POPS WILL BE WARRANTED. TEMPERATURE GUIDANCE HAS
TAKEN A JOG TO WARMER NUMBERS AS HAS THE OFFICIAL FORECAST.
&&
.AVIATION /07Z WEDNESDAY THROUGH SUNDAY/...
AS OF 06Z...EXPECT VFR THROUGH THE PERIOD WITH THE EXCEPTION OF MVFR
DUE TO FOG AT THE INLAND SITES LATE OVERNIGHT BEFORE DAYBREAK.
LIGHT WINDS AND MAINLY MID AND HIGH CLOUDS WILL CONTINUE INTO THE
OVERNIGHT HOURS. ANTICIPATE MVFR DUE TO FOG TO DEVELOP IN A FEW
HOURS AT FLO AND LBT. MOISTURE POOLING AROUND 2000 FT AGL COULD ALSO
DEVELOP SOME STRATUS AT THE INLAND AIRPORTS. AFTER DAYBREAK...VFR
WILL PREVAIL WITH LIGHT SOUTH-SOUTHEAST WINDS BECOMING AOB 10 KTS ON
WEDNESDAY...BECOMING LIGHT INTO THE EVENING HOURS.
EXTENDED OUTLOOK...ISOLATED AFTERNOON SHOWERS AND THUNDERSTORMS
POSSIBLE WEDNESDAY THROUGH SUNDAY. OTHERWISE VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM WEDNESDAY...THE ONLY CHANGE TO THE FORECAST WAS TO BACK
WIND DIRECTIONS BY 20-30 DEGREES FOR THE REMAINDER OF THE MORNING...
STILL VEERING SOUTHEASTERLY THIS AFTERNOON. WIND SPEEDS AND SEA
HEIGHTS STILL LOOK GOOD. PREVIOUS DISCUSSION FROM 300 AM FOLLOWS...
HIGH PRESSURE OFF THE MID-ATLANTIC COAST
SHOULD MOVE FARTHER OUT TO SEA TODAY...BUT A SURFACE RIDGE AXIS WILL
REMAIN PARKED ACROSS INTERIOR NORTH CAROLINA. UNTIL THIS RIDGE AXIS
BREAKS DOWN DURING THE DAY THURSDAY OUR WIND DIRECTIONS WILL NOT
VEER SIGNIFICANTLY FROM EAST-SOUTHEAST. MODELS ARE IN EXCELLENT
AGREEMENT WITH WIND SPEEDS...EXPECTED TO AVERAGE 10 KNOTS BOTH TODAY
AND TONIGHT. SEAS CURRENTLY AROUND 2 FT SHOULD CHANGE VERY LITTLE
THROUGH TONIGHT WITH VIRTUALLY NO SWELL ENERGY VISIBLE ON SPECTRAL
WAVE PLOTS FROM THE FRYING PAN SHOALS BUOY.
SHOWER CHANCES WILL REMAIN VERY LOW THROUGH THIS EVENING...BUT MAY
INCREASE A LITTLE AFTER MIDNIGHT TONIGHT...ESPECIALLY OFFSHORE.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 300 AM WEDNESDAY...WIND DIRECTIONS WILL BE A ISSUE AT LEAST
EARLY IN THE PERIOD AS A WEAK COASTAL TROUGH ALLOWS FOR SOUTHEAST
WINDS MOST OF THE DAY THURSDAY BEFORE A SOUTHWEST FLOW DEVELOPS.
THIS SOUTHWEST FLOW WILL CONTINUE THROUGH THE REMAINDER OF THE
PERIOD. A WEAK PRESSURE PATTERN WILL BE IN PLACE THROUGHOUT THE
PERIOD WITH WIND SPEEDS A COUPLE KNOTS EITHER SIDE OF TEN
KNOTS.WAVEWATCH AND SWAN SEAS ARE IN GOOD AGREEMENT ON SIGNIFICANT
SEAS OF 2-3 FEET.
LONG TERM /SATURDAY THROUGH SUNDAY/...
AS OF 300 AM WEDNESDAY...PERSISTENCE IS THE NAME OF THE GAME WITH
REGARDS TO THE COASTAL WATERS FORECAST FOR THE WEEKEND. EXPECT A
SOUTHWEST FLOW OF 10-15 KNOTS AS BERMUDA HIGH PRESSURE REMAINS THE
DOMINANT FEATURE. WAVEWATCH SEAS REMAIN IN A 2-4 FOOT RANGE.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...TRA
SHORT TERM...SHK
LONG TERM...SHK
AVIATION...SGL
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
312 AM EDT WED AUG 7 2013
.SYNOPSIS...
A PATTERN MORE TYPICAL OF SUMMER...WARM TEMPERATURES AND AFTERNOON
AND EVENING THUNDERSTORMS WILL DEVELOP OVER THE NEXT FEW DAYS
ACROSS THE AREA. LATE IN THE PERIOD RAIN CHANCES MAY INCREASE AS A
FRONT MOVES CLOSER TO THE AREA.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 300 AM WEDNESDAY...AFTER YESTERDAY`S FORECAST DEBACLE ALONG
AND WEST OF THE INTERSTATE 95 CORRIDOR...I AM HOPING THIS IS A
BETTER FORECAST FOR TODAY. SURFACE HIGH PRESSURE IS DEPARTING THE
COASTAL MID-ATLANTIC REGION...BUT A RIDGE AXIS REMAINS ENTRENCHED
ACROSS THE INTERIOR CAROLINAS. EASTERLY FLOW ACROSS THE ATLANTIC IS
GRADUALLY WARMING AND MOISTENING AS THE SOURCE REGION FOR THE
INCOMING STREAMLINES SHIFTS TO BERMUDA INSTEAD OF EASTERN CANADA.
THE UPPER LEVEL PATTERN FEATURES A 500 MB RIDGE OVER EASTERN TEXAS
WITH A WEAKENING LONGWAVE TROUGH OVER THE EASTERN U.S. 500 MB
HEIGHTS SHOULD RISE BY ABOUT 20 METERS OVER THE CAROLINAS TODAY. ONE
POTENTIAL PROBLEM DESPITE THE BUILDING RIDGE IS A WEAK SHORTWAVE
TROUGH EMBEDDED IN THE WESTERLY UPPER LEVEL FLOW. THIS FEATURE IS
COLOCATED WITH A CLUSTER OF THUNDERSTORMS IN NORTH GEORGIA EARLY
THIS MORNING...AND IS DEPICTED BETTER IN THE GFS THAN THE NAM. IT
SHOULD TRANSIT THE EASTERN CAROLINAS DURING THE LATE AFTERNOON
HOURS...WEAKENING ALONG THE COAST THIS EVENING AS A COL (WEAK WIND
REGION) DEVELOPS IN BETWEEN THE TEXAS AND BERMUDA RIDGES.
AT THE RISK OF MAKING THE SAME MISTAKE I DID YESTERDAY...I SEE A
VERY LOW RISK FOR SHOWERS TODAY GIVEN INSUFFICIENT MOISTURE AND WEAK
LAPSE RATES WITHIN THE LOWER TROPOSPHERE. FORECAST SOUNDINGS FROM
THE GFS...ECMWF AND RUC SHOW A CAPPED CONVECTIVE ENVIRONMENT. ONLY
THE NAM DEVELOPS ANY SUBSTANTIAL SURFACE-BASED OR ELEVATED
INSTABILITY TODAY (DUE TO SURFACE DEWPOINTS THAT LOOK TOO HIGH) BUT
THAT MODEL ALSO SHOWS INSUFFICIENT FORCING FOR SHOWERS. THE 200-300
MB JET STREAM IS NOW WELL NORTH AND EAST OF THE CAROLINAS...TAKING
ANY POTENTIAL UPPER DIVERGENT REGIONS OUT OF THE PICTURE LOCALLY.
SCATTERED MID-LEVEL CLOUDS COULD BECOME A LITTLE MORE SUBSTANTIAL AT
TIMES INLAND TODAY...BUT SHOULD NOT DO TOO MUCH TO HOLD TEMPERATURES
DOWN. HIGHS ARE EXPECTED TO REACH 87-88 INLAND WITH MID 80S NEAR THE
COAST.
FOR TONIGHT MOSTLY CLEAR TO PARTLY CLOUDY SKIES ARE EXPECTED WITH
LOWS 69-74...WARMEST AT THE COAST. MODELS ARE HINTING AT THE
SOUTHEAST FLOW ALONG THE COAST POTENTIALLY YIELDING SOME MARINE
SHOWERS AFTER MIDNIGHT...SO I HAVE SHOWN A TREND OF INCREASING POPS
TOWARD SUNRISE THURSDAY AT THE BEACHES.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 300 AM WEDNESDAY...TYPICAL SUMMERTIME PATTERN FOR THE SHORT TERM
FORECAST THROUGH THE PERIOD WITH MID LEVEL RIDGING WITH THE
SEABREEZE AND PIEDMONT TROUGH BEING THE CATALYST FOR CONVECTION.
THE CONVECTION WILL BE MORE WIDESPREAD DURING THE AFTERNOON AND
EARLY EVENING HOURS. I HAVE MADE SOME SUBTLE ADJUSTMENTS IN POPS
MAINLY TO MATCH ADJACENT OFFICES BETTER. NUMERICAL GUIDANCE YIELDS
LITTLE CHANCE WITH THE 0000 BULLETINS AND TEMPERATURE FORECAST
REMAINS UNCHANGED FOR THE MOST PART.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 300 AM WEDNESDAY...MID LEVEL PATTERN SHOWS AN ELONGATED RIDGE
ACROSS THE SOUTHERN U.S. SHIFTING MORE WESTWARD THROUGH THE
PERIOD AS DECENT EAST COAST TROUGHING DEVELOPS ACROSS THE OHIO
VALLEY. AT THE SURFACE THE PERSISTENT BERMUDA RIDGE SLOWLY GIVES
WAY TO A FRONT DROPPING SOUTH WITH THE AFOREMENTIONED TROUGH. THIS
FEATURE WILL PROVIDE A FOCUS FOR CONVECTION/POPS SATURDAY THROUGH
TUESDAY. DON/T SEE ANY REASON TO GO ABOVE CHANCE POPS AT THIS TIME
BUT AS WE DRAW CLOSER THERE WILL ALMOST CERTAINLY BE PERIODS WHERE
AT LEAST LIKELY POPS WILL BE WARRANTED. TEMPERATURE GUIDANCE HAS
TAKEN A JOG TO WARMER NUMBERS AS HAS THE OFFICIAL FORECAST.
&&
.AVIATION /07Z WEDNESDAY THROUGH SUNDAY/...
AS OF 06Z...EXPECT VFR THROUGH THE PERIOD WITH THE EXCEPTION OF MVFR
DUE TO FOG AT THE INLAND SITES LATE OVERNIGHT BEFORE DAYBREAK.
LIGHT WINDS AND MAINLY MID AND HIGH CLOUDS WILL CONTINUE INTO THE
OVERNIGHT HOURS. ANTICIPATE MVFR DUE TO FOG TO DEVELOP IN A FEW
HOURS AT FLO AND LBT. MOISTURE POOLING AROUND 2000 FT AGL COULD ALSO
DEVELOP SOME STRATUS AT THE INLAND AIRPORTS. AFTER DAYBREAK...VFR
WILL PREVAIL WITH LIGHT SOUTH-SOUTHEAST WINDS BECOMING AOB 10 KTS ON
WEDNESDAY...BECOMING LIGHT INTO THE EVENING HOURS.
EXTENDED OUTLOOK...ISOLATED AFTERNOON SHOWERS AND THUNDERSTORMS
POSSIBLE WEDNESDAY THROUGH SUNDAY. OTHERWISE VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 300 AM WEDNESDAY...HIGH PRESSURE OFF THE MID-ATLANTIC COAST
SHOULD MOVE FARTHER OUT TO SEA TODAY...BUT A SURFACE RIDGE AXIS WILL
REMAIN PARKED ACROSS INTERIOR NORTH CAROLINA. UNTIL THIS RIDGE AXIS
BREAKS DOWN DURING THE DAY THURSDAY OUR WIND DIRECTIONS WILL NOT
VEER SIGNIFICANTLY FROM EAST-SOUTHEAST. MODELS ARE IN EXCELLENT
AGREEMENT WITH WIND SPEEDS...EXPECTED TO AVERAGE 10 KNOTS BOTH TODAY
AND TONIGHT. SEAS CURRENTLY AROUND 2 FT SHOULD CHANGE VERY LITTLE
THROUGH TONIGHT WITH VIRTUALLY NO SWELL ENERGY VISIBLE ON SPECTRAL
WAVE PLOTS FROM THE FRYING PAN SHOALS BUOY.
SHOWER CHANCES WILL REMAIN VERY LOW THROUGH THIS EVENING...BUT MAY
INCREASE A LITTLE AFTER MIDNIGHT TONIGHT...ESPECIALLY OFFSHORE.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 300 AM WEDNESDAY...WIND DIRECTIONS WILL BE A ISSUE AT LEAST EARLY
IN THE PERIOD AS A WEAK COASTAL TROUGH ALLOWS FOR SOUTHEAST WINDS
MOST OF THE DAY THURSDAY BEFORE A SOUTHWEST FLOW DEVELOPS. THIS
SOUTHWEST FLOW WILL CONTINUE THROUGH THE REMAINDER OF THE PERIOD.
A WEAK PRESSURE PATTERN WILL BE IN PLACE THROUGHOUT THE PERIOD WITH
WIND SPEEDS A COUPLE KNOTS EITHER SIDE OF TEN KNOTS.WAVEWATCH AND
SWAN SEAS ARE IN GOOD AGREEMENT ON SIGNIFICANT SEAS OF 2-3 FEET.
LONG TERM /SATURDAY THROUGH SUNDAY/...
AS OF 300 AM WEDNESDAY...PERSISTENCE IS THE NAME OF THE GAME WITH REGARDS
TO THE COASTAL WATERS FORECAST FOR THE WEEKEND. EXPECT A SOUTHWEST
FLOW OF 10-15 KNOTS AS BERMUDA HIGH PRESSURE REMAINS THE DOMINANT
FEATURE. WAVEWATCH SEAS REMAIN IN A 2-4 FOOT RANGE.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...SHK
NEAR TERM...TRA
SHORT TERM...SHK
LONG TERM...SHK
AVIATION...SGL
AREA FORECAST DISCUSSION
NWS RALEIGH NC
300 AM EDT WED AUG 7 2013
.SYNOPSIS...
A MOIST SOUTHERLY RETURN FLOW WILL PREVAIL ACROSS THE REGION THROUGH
MID TO LATE WEEK...ON THE WESTERN PERIPHERY OF AN OFFSHORE RIDGE. A
COLD FRONT WILL MOVE INTO THE REGION BY THIS WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 255 AM WEDNESDAY...
PERSISTENCE WILL DOMINATE THE FORECAST TODAY AS SOUTHERLY LOW-LEVEL
FLOW CONTINUES BENEATH WEST-NORTHWESTERLY FLOW ALOFT. WEAK WARM
ADVECTION...MASS CONVERGENCE ALONG THE HIGHER TERRAIN... AND
MOISTURE POOLING OVER WESTERN WILL PROMOTE SCATTERED SHOWERS BY THIS
AFTERNOON. THE MOST RECENT HRRR RUN INDICATES SHOWERS NEAR THE TRIAD
BY AROUND NOON. DESPITE DEWPOINTS IN THE MID AND UPPER
60S...WIDESPREAD CLOUD COVER...BOTH AT LOW-LEVELS AND ALOFT...ALONG
WITH WEAK MID-LEVEL LAPSE RATES WILL KEEP MLCAPE AT 500 J/KG OR LESS
EAST OF THE MOUNTAINS. A WEAK UPPER DISTURBANCE LEFT OVER FROM
CONVECTION OVER MISSOURI IS CROSSING THE TN VALLEY THIS
MORNING...BUT THE MODEL CONSENSUS IS FOR THE DISTURBANCE TO CONTINUE
TO WEAKEN AS IT DROPS EAST-SOUTHEAST TOWARD GEORGIA AND SC.
THUS..THE CHANCE OF STORMS IS RATHER LOW TODAY. FORECAST SOUNDINGS
SUGGEST A FEW MORE BREAKS IN CLOUD COVER TODAY...BUT THE STRATUS
OVER THE WESTERN PIEDMONT THIS MORNING AND HIGH CLOUDS DRIFTING
OVERHEAD SHOULD HOLD TEMPS DOWN OVER THE WESTERN CWA...WITH 82-87 A
GOOD COMPROMISE OF STATISTICAL GUIDANCE.
TONIGHT
IN THE ABSENCE OF ANY SIGNIFICANT FORCING ALOFT...SHOWERS SHOULD BE
DIURNAL IN NATURE AND THE OVERNIGHT PERIOD DRY. STRATUS IS LIKELY
AGAIN OVER THE WESTERN PIEDMONT...WITH LOWS IN THE UPPER 60S TO
AROUND 70...WARMEST IN THE WEST.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/...
AS OF 300 AM WEDNESDAY...
THURSDAY AND THURSDAY NIGHT...
HEIGHTS ALOFT ARE EXPECTED TO RISE SLIGHTLY ON THURSDAY AS THE UPPER
RIDGE OVER THE SOUTHERN US BRIEFLY EXPANDS EASTWARD AND A SHORTWAVE
BEGINS TO DIVE SOUTH OUT OF CENTRAL CANADA. PW VALUES WILL CONTINUE
TO CREEP UP TO ABOVE 1.75`...BUT THE LACK OF FORCING
AND AFOREMENTIONED RIDGING ALOFT SHOULD KEEP CONVECTION CONFINED TO
THE SEABREEZE AND HIGHER TERRAIN. HIGHS IN THE MID TO UPPER 80S.
LOWS THURSDAY NIGHT AROUND 70. -SMITH
FOR FRIDAY/FRIDAY NIGHT: THE CANADIAN MIDLEVEL VORTEX MOVES FROM
CENTRAL ONTARIO OVER QUEBEC THROUGH FRI NIGHT WITH THE TRAILING
BROAD TROUGH AXIS SHIFTING ACROSS THE GREAT LAKES INTO THE
MIDATLANTIC AND NORTHEAST. THE ASSOCIATED SURFACE COLD FRONT BECOMES
MORE EAST-WEST ORIENTED TO OUR NORTH WHILE HEIGHTS ALOFT RISE
SLIGHTLY OVER NC. THE UPPER LEVEL ANTICYCLONE TO OUR SOUTH SHIFTS
EASTWARD... AND THE STRENGTHENING WESTERLY FLOW AT JET LEVEL INDUCES
INCREASING UPPER DIVERGENCE OVER VA INTO CENTRAL NC (ALTHOUGH MODELS
DIFFER ON THE DETAILS)... AND THE STRENGTHENING AND VEERING LOW
LEVEL FLOW (WITH THE 850 MB TROUGH PASSAGE) RESULTS IN STRENGTHENING
MOISTURE TRANSPORT PARTICULARLY OVER NORTH CENTRAL AND NORTHEAST NC
IN THE AFTERNOON THROUGH EVENING. MODERATE INSTABILITY (MLCAPE OF
1200-1800 J/KG) IS EXPECTED FRI AFTERNOON/EVENING BUT WITH POOR
DEEP-LAYER SHEAR UNDER 20 KTS FOR MUCH OF THE DAY...ALTHOUGH THIS
DOES IMPROVE SLIGHTLY OVERNIGHT AS MIDLEVEL WINDS STRENGTHEN NEAR
THE NC/VA BORDER... WHILE SOME WEAK ELEVATED INSTABILITY LINGERS.
GIVEN THIS COMBINATION OF INSTABILITY AND WEAK DYNAMIC FORCING FOR
ASCENT WITH HIGH PW AT OR ABOVE 2.0 INCHES... AT LEAST A 50%
COVERAGE OF SHOWERS/STORMS IS JUSTIFIED ACROSS THE WRN/NRN CWA WHERE
MOISTURE TRANSPORT IS HIGHEST ALONG THE LEE SURFACE TROUGH... WITH A
LITTLE LOWER CHANCE OVER THE SOUTHEAST CLOSER TO THE MIDLEVEL
ANTICYCLONE CENTER. HIGHS 88-92. RAIN CHANCES SHOULD WIND DOWN BY
LATE EVENING AS LOW LEVEL FLOW BECOMES MORE WESTERLY WITH DOWNSLOPE
DRYING AND INCREASING STABILITY AFTER SUNSET... BUT THE ANOMALOUSLY
HIGH MOISTURE CONTENT OF THE COLUMN SUPPORTS A CONTINUED THREAT OF
ISOLATED SHOWERS OVERNIGHT. LOWS 70-74.
FOR SATURDAY/SATURDAY NIGHT: THIS STILL LOOKS LIKE THE WETTEST DAY
OF THIS FORECAST. HEIGHTS ALOFT BEGIN TO FALL OVER THE APPALACHIANS
INTO CENTRAL NC AS ENERGY TRACKS INTO THE TROUGH BASE... FROM
ONTARIO ACROSS THE OH VALLEY... WHILE DEEP MOISTURE PERSISTS OVER
THE LINGERING LEE TROUGH OVER CENTRAL NC AHEAD OF THE APPROACHING
LARGE SCALE FRONTAL ZONE TO OUR NORTH AND NORTHWEST. THE INCREASING
DPVA... HIGH LOW-LEVEL THETA-E... HIGH PW... AND MODERATE
INSTABILITY SUPPORTS A 50-60% CHANCE OF SHOWERS/STORMS... HIGHEST IN
THE NW AND NORTHERN CWA WHERE UPPER DIVERGENCE WILL BE GREATEST IN
THE RIGHT ENTRANCE REGION OF THE 80-100 KT JET CORE OVER/OFF NEW
ENGLAND. HIGHS 88-93 AS THE ABOVE-NORMAL THICKNESSES ARE TEMPERED BY
ABUNDANT CLOUDINESS AND THE EARLY ONSET OF CONVECTION. LOWS AGAIN
70-74 WITH PLENTY OF CLOUDS AND A FEW RESIDUAL SHOWERS OVERNIGHT.
-GIH
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
AS OF 250 AM WEDNESDAY...
THE AMPLIFICATION OF THE EASTERN US TROUGH CONTINUES INTO EARLY NEXT
WEEK AS A SECONDARY VORTEX DROPS DOWN THROUGH ERN ONTARIO/JAMES BAY.
MODELS INDICATE THAT THE SURFACE FRONT WILL SINK SLOWLY SE INTO FAR
NRN AND WRN NC SUNDAY/SUNDAY NIGHT. WITH INCREASING DYNAMIC
FORCING... MODERATE AFTERNOON INSTABILITY (2000-2500 J/KG MAINLY
ALONG/EAST OF HIGHWAY 1)... AND CONTINUED HIGH MOISTURE THROUGH THE
COLUMN... HIGH PROBABILITIES OF SHOWERS/STORMS SHOULD EXTEND THROUGH
SUNDAY. THE GFS/ECMWF SWING THE MIDLEVEL LOW OVER SE ONTARIO AND SRN
QUEBEC/UPPER ST LAWRENCE... AMPLIFYING THE SOUTHERN PORTION OF THE
MEAN TROUGH SUFFICIENTLY SO AS TO NUDGE THE FRONT TO ERN/SRN NC FOR
MONDAY/TUESDAY. CONSIDERING THAT THE MODEL RUNS FROM A FEW DAYS AGO
WERE PUSHING THIS FRONT TO OUR SOUTH AS EARLY AS SUNDAY AND HAVE NOW
BACKED OFF ON THAT SCENARIO... AND CONSIDERING THAT TRUE COLD FRONT
PASSAGE THROUGH NC WITHOUT A STRONG AMPLIFYING TROUGH IS A RARITY...
I HAVE SOME RESERVATIONS ABOUT BRINGING IN A LOT OF STABLE OR
MARKEDLY COOLER AIR INTO THE NRN/WRN CWA. WILL HOLD ONTO DAILY
CHANCE POPS OVER THE ERN/SRN CWA... NEAR THE LIKELY POSITION OF THE
FRONTAL ZONE... WITH SLIGHTLY LOWER POPS (BUT NOT ZERO) OVER THE NW
BOTH MONDAY AND TUESDAY. THICKNESSES SHOULD DIP A BIT HEADING INTO
EARLY NEXT WEEK... SO EXPECT HIGHS TO TREND FROM AROUND 90 SUNDAY
INTO THE MID-UPPER 80S BY TUESDAY. LOWS IN THE UPPER 60S TO LOWER
70S... SLIPPING 2-3 DEGREES FROM SUNDAY TO TUESDAY. -GIH
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
AS OF 140 AM WEDNESDAY...
THE PATTERN OF A MOIST SOUTHERLY FLOW AND BETTER CHANCES OF SHOWERS
OVER THE WESTERN PIEDMONT WILL CONTINUE THROUGH THE TAF PERIOD. MVFR
CEILINGS HAVE ALREADY DEVELOPED AT KGSO AND KINT...AND MAY LOWER TO
IFR BY 10Z BASED ON FORECAST SOUNDINGS AND NEARBY OBSERVATIONS. TO
THE EAST...MUCH DRIER LOW LEVEL AIR AND PERIOD OF HIGH CLOUDS SHOULD
MAINTAIN VFR CONDITIONS...WITH JUST A SMALL CHANCE OF MVFR VSBYS AT
KRWI/KFAY PRIOR TO SUNRISE.
TODAY...WHERE STRATUS DOES DEVELOP...A SLOW LIFTING AND SCATTERING
OF CEILINGS IS EXPECTED...ALTHOUGH VFR CONDITIONS SHOULD PREVAIL
EVEN IN THE TRIAD BY MIDDAY. A FEW SHOWERS WILL BE POSSIBLE AROUND
KGSO AND KINT...MAINLY AFTER 18Z.
OUTLOOK...
MORNING STRATUS AND AFTERNOON SHOWERS/STORMS WILL BE POSSIBLE EACH
DAY FOR THE REMAINDER OF THE WEEK...ALTHOUGH THE COVERAGE OF SHOWERS
AND STORMS IS EXPECTED TO INCREASE FRIDAY AND SATURDAY AS A COLD
FRONT MOVES INTO THE REGION FROM THE NORTHWEST.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...SMITH
SHORT TERM..SMITH/HARTFIELD
LONG TERM...HARTFIELD
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
906 PM CDT THU AUG 8 2013
.UPDATE...
ISSUED AT 906 PM CDT THU AUG 8 2013
LATEST SATELLITE IMAGERY AND REGIONAL RADAR SHOWS THE SHORTWAVE IN
FAR SOUTHERN SASKATCHEWAN IS WEAKENING WITH TIME AS SHOWERS
CONTINUE TO WEAKEN AS THEY MOVE INTO FAR NORTHWEST NORTH DAKOTA.
WILL CARRY A SLIGHT CHANCE FOR THE NEXT HOUR OR TWO MAINLY FOR
DIVIDE COUNTY. OTHERWISE DRY AND MOSTLY CLEAR FOR ALL AREAS EXCEPT
IN THE FAR SOUTHWEST WHERE CLOUD DEBRIS IS QUICKLY APPROACHING FAR
SOUTHEAST MONTANA AND NORTHWEST SOUTH DAKOTA. THE RAP MAINTAINS
SOME LIGHT PRECIPITATION CHANCES DEVELOPING IN THE FAR SOUTHWEST
AS A SHORTWAVE PUSHES THROUGH SOUTH CENTRAL MONTANA. INSTABILITY
REMAINS WEAK AND WILL CONTINUE TO MONITOR FOR THE POSSIBILITY OF A
SHOWER OR TWO DEVELOPING AFTER MIDNIGHT...HOWEVER THE 00Z NAM IS
DRY...SO NOT REAL CONFIDENT IN THIS OCCURRING. LOOKING AHEAD...SLIGHTLY
BETTER INSTABILITY REACHES FAR SOUTHWESTERN NORTH DAKOTA FRIDAY
AFTERNOON/EVENING FOR CHANCE OF SHOWERS AND THUNDERSTORMS. WILL
ADJUST SKY GRIDS IN THE NORTHWEST AND SOUTHWEST TO ACCOUNT FOR THE
INCREASE IN CLOUDS. OTHER UPDATES WERE MAINLY TO HOURLY SENSIBLE
WEATHER ELEMENTS.
UPDATE ISSUED AT 457 PM CDT THU AUG 8 2013
LATEST WATER VAPOR IMAGERY SHOWS NORTHWEST FLOW CONTINUING WITH AN
UPSTREAM MID LEVEL SHORTWAVE LOCATED IN SOUTH CENTRAL SASKATCHEWAN.
REGIONAL RADAR SHOWS ISOLATED RAIN SHOWERS JUST NORTH OF THE MONTANA
BORDER MOVING SOUTHEAST WITH TIME. LIGHT RAIN AT SWIFT CURRENT PER
LATEST SURFACE OBSERVATIONS AND THE GFS HAS THE BEST HANDLE ON THE
PRECIPITATION AREA...WITH THE RAP NOT FAR BEHIND. THE GFS HOLDS A
THIN AREA OF LIGHT SHOWERS TOGETHER AS THEY MOVE INTO NORTHWESTERN
NORTH DAKOTA THIS EVENING AND WILL FOLLOW. THE RAP SHOWS A WEAKENING
OF THE SHOWERS AND KEEPS IT DRY. BASED ON THE LATEST RADAR AND
SURFACE OBSERVATIONS...THINK ENOUGH EVIDENCE UPSTREAM AND IN THE
GFS SOLUTION TO SOLIDIFY A MENTION OF ISOLATED SHOWERS NORTHWEST
INTO PORTIONS OF NORTH CENTRAL TONIGHT. THE GFS H7-H5 RELATIVE
HUMIDITY FIELD ALSO MATCHES THE VISIBLE SATELLITE IMAGERY WELL WHEN
OVERLAID AND THUS WILL INCREASE SKY GRIDS A BIT TO CAPTURE THIS.
ALSO AS MENTIONED FROM THE PREVIOUS DISCUSSION BELOW THE OTHER INTEREST
OVERNIGHT COULD BE OUR FAR SOUTHWEST ZONES...WHERE CONVECTION OVER
NORTHERN WYOMING THIS AFTERNOON IS FORECAST TO BUILD FURTHER NORTH
AND POSSIBLY SEEP INTO THE SOUTHWEST BY AROUND 04Z FRIDAY...PER
RAP MODEL. THE HRRR MODEL HAS CHANGED ITS COURSE BY KEEPING THE
REFLECTIVITY`S SOUTH WHEREAS EARLIER IT ALSO MAKE A TRACK INTO
SOUTHWEST NORTH DAKOTA. WILL CONTINUE TO MONITOR...OTHERWISE
MOSTLY CLEAR TO PARTLY CLOUDY SKIES CAN BE ANTICIPATED FOR THE
REST OF WESTERN AND CENTRAL NORTH DAKOTA THIS EVENING INTO TONIGHT.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 317 PM CDT THU AUG 8 2013
CURRENTLY...HIGH PRESSURE CONTINUES TO BUILD ACROSS WESTERN AND
CENTRAL NORTH DAKOTA. THE COOL HIGH PRESSURE SUPPRESS AND
THUNDERSTORM ACTIVITY LAT THIS AFTERNOON AND TONIGHT. BUT A FEW
SPRINKLES OR AN ISOLATED SHOWER CANNOT BE RULED OUT LATE THIS
AFTERNOON.
TONIGHT...THE SURFACE HIGH PRESSURE RIDGE REMAINS SITUATED
NORTHWEST TO SOUTHEAST ACROSS THE CWA...WHILE SHORTWAVE ENERGY
APPROACHES EASTERN NORTH DAKOTA AND ALSO SOUTHWEST NORTH DAKOTA.
THIS WILL LIKELY RESULT IN LITTLE MORE THAN INCREASING CLOUDS OVER
THE SOUTHWEST AND SOUTH CENTRAL LATE TONIGHT. SOME OF THE MODELS
ARE INDICATING VERY LIGHT QPF IN THE SOUTHWEST BETWEEN 06-12Z
FRIDAY. BUT FOR NOW KEPT WITH THE CURRENT DRY FORECAST. EXPECT A
COOL NIGHT WITH HIGHS RANGING FROM THE MID 40S FAR NORTH TO THE
LOW TO MID 50S FAR SOUTH.
SHORTWAVE ENERGY WORKING THROUGH A NORTHERN ROCKIES UPPER RIDGE
WILL SUPPORT SHOWERS AND THUNDERSTORMS ACROSS SOUTHEAST
MONTANA...NORTHERN WYOMING AND WESTERN SOUTH DAKOTA FRIDAY
AFTERNOON. IT IS POSSIBLE THAT A FEW OF THESE SHOWERS OR
THUNDERSTORMS COULD MOVE INTO THE SOUTHWEST FRIDAY AFTERNOON.
HOWEVER...GUIDANCE CONTINUES TO TREND FARTHER SOUTH SO WILL
CONTINUE WITH PERSISTENCE AND KEEP THINGS DRY ON FRIDAY.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 317 PM CDT THU AUG 8 2013
A SLOW WARMING TREND POTENTIALLY BACK TO NEAR NORMAL TEMPERATURES
NEXT WEEK WILL HIGHLIGHT THE EXTENDED FORECAST.
THE 12 UTC GUIDANCE SUITE IS IN GOOD AGREEMENT ON NORTHWEST FLOW
ALOFT CONTINUING THROUGH MONDAY...BEFORE A POTENTIAL SHIFT OF THE
UPPER LEVEL RIDGE AXIS ACROSS THE NORTHERN PLAINS TUESDAY ONWARD.
THIS WOULD SUPPORT A SLOW WARMING TREND FROM THE RECENT BELOW NORMAL
TEMPERATURES TO WIDESPREAD HIGHS IN THE 80S BY MID TO LATE NEXT
WEEK. IN REGARDS TO PRECIPITATION CHANCES...THERE IS CHANCE OF
THUNDERSTORMS SATURDAY AND SATURDAY NIGHT AS THE LAST OF THE
SIGNIFICANT WAVES EMBEDDED IN NORTHWEST FLOW PROPAGATES ACROSS THE
NORTHERN PLAINS. THEREAFTER...THUNDERSTORM CHANCES HOLD OFF UNTIL
MID TO LATE NEXT WEEK WITH INCREASING MOISTURE TRANSPORT UNDER THE
RIDGE AHEAD OF LEE SURFACE LOW PRESSURE.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 906 PM CDT THU AUG 8 2013
VFR CIGS/VSBYS EXPECTED NEXT 24HR. EXPECT SKC TO SCT MID LEVEL CLOUDS
FOR THE REST OF THURSDAY NIGHT ACROSS THE AERODROMES. KMOT/KDIK
MAY SEE AN INCREASE IN CLOUDS WITH SCT/BKN VFR CIGS FRIDAY.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KS
SHORT TERM...TWH
LONG TERM...AYD
AVIATION...KS
AREA FORECAST DISCUSSION
NWS BISMARCK ND
542 PM CDT WED AUG 7 2013
.UPDATE...
ISSUED AT 542 PM CDT WED AUG 7 2013
LATEST WATER VAPOR IMAGERY SHOWS A SHORTWAVE NOW WORKING ITS WAY
INTO NORTHEAST MONTANA FROM SOUTHERN SASKATCHEWAN. AN AREA OF RAIN
SHOWERS CONTINUE TO MOVE INTO NORTHWEST NORTH DAKOTA. THE LATEST
RAP HAS A GOOD READ ON THE ACTIVITY AS SCOOTS IT ACROSS THE NORTH
CENTRAL THIS EVENING. IN ADDITION...WILL WATCH FOR SHOWERS TO
DEVELOP IN THE WEST AND SOUTH CENTRAL EARLY TONIGHT PER RAP MODEL.
RADAR SHOWING A WEAK LINE TRYING TO GENERATE FROM NEAR WILLISTON
SOUTH TO TROTTERS AT THIS MOMENT. BEST FORCING REMAINS NORTH. THUS
WILL CONTINUE WITH SCATTERED SHOWERS/ISOLATED THUNDERSTORMS NORTH
THIS EVENING AND ISOLATED SHOWERS/THUNDERSTORMS WEST AND CENTRAL
OVERNIGHT. GIVEN THE WEAK INSTABILITY...THUNDER SHOULD REMAIN
ISOLATED. MINOR UPDATES TO HOURLY TEMPS/DEWPOINTS AND CHANGED
UNCERTAINTY WORDING TO AREAL COVERAGE IN THE WEATHER GROUP BASED
ON RADAR.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 338 PM CDT WED AUG 7 2013
CURRENTLY...A STRONG UPPER LEVEL JET AND A SHORTWAVE IMPULSE
TRACKING ACROSS SOUTHERN SASKATCHEWAN IS RESPONSIBLE FOR PRODUCING
SCATTERED SHOWERS FROM NORTHEAST MONTANA INTO NORTHWEST NORTH
DAKOTA. THE SHOWERS ARE EXPECTED TO TRACK EAST AND SOUTH ACROSS
THE AREA LATE THIS AFTERNOON AND THIS EVENING. SIMILAR TO THE
TRACK OF A SHORTWAVE YESTERDAY. THE MAIN DIFFERENCE IS THE
ATMOSPHERE IS MORE STABLE TODAY. HOWEVER...WITH A STRONG UPPER
LEVEL JET AND SHORTWAVE...WE CANNOT RULE OUT A FEW THUNDERSTORMS
THIS AFTERNOON AND EARLY EVENING...WITH SMALL HAIL AND GUSTY
WINDS. HOWEVER IN THE FORECAST WE LIMITED THE BEST CHANCES TO THE
NORTH LATE THIS AFTERNOON...AND WITH LIMITED INSTABILITY AND
CAPPING ALOFT...WE KEPT A MENTION OF SHOWERS WITH ONLY ISOLATED
THUNDERSTORMS. EXPECT PRECIPITATION CHANCES TO DIMINISH AS THE
SYSTEM TRACKS SOUTHEAST. BUT THE LATEST RAP AND HRRR HOLD
REFLECTIVITIES TOGETHER AS THEY TRACK INTO THE SOUTHEAST CWA
AROUND MIDNIGHT.
MODELS HAVE TRENDED FARTHER SOUTH WITH THE NEXT WAVE COMING INTO
THE AREA AFTER MIDNIGHT. HAVE THEREFORE CONTINUED THE TREND OF
LOWERING POPS ACROSS THE AREA. CURRENTLY HAVE CHANCE POPS ACROSS
THE FAR SOUTHWEST AND SOUTH CENTRAL LATE TONIGHT...AND HAVE
DROPPED POPS ACROSS THE SOUTH ON THURSDAY MORNING. ANOTHER
SHORTWAVE MOVING ACROSS ALBERTA TONIGHT WILL DROP SOUTHEAST INTO
THE LOCAL AREA THURSDAY AFTERNOON. THIS COULD DEVELOP AN ISOLATED
SHOWERS ACROSS THE NORTH DURING THE AFTERNOON. TEMPERATURES WILL
REMAIN ON THE COOL SIDE WITH HIGHS RANGING FROM THE 60S NORTH TO
THE 70S SOUTH.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 338 PM CDT WED AUG 7 2013
CONTINUED BELOW NORMAL TEMPERATURES WILL HIGHLIGHT THE EXTENDED
FORECAST.
AS HAS BEEN THE PATTERN OVER THE LAST COUPLE WEEKS...NORTHWEST
FLOW ALOFT WILL CONTINUE ACROSS THE NORTHERN PLAINS THROUGH THE
EXTENDED. THIS FAVORS BELOW NORMAL TEMPERATURES WITH HIGHS
GENERALLY IN THE 70S...PERHAPS RECOVERING INTO THE LOWER 80S BY
MID NEXT WEEK. OVERALL...THE COOLER EDGE OF GUIDANCE HAS BEEN
HANDLING THIS PATTERN BETTER...AND THUS UTILIZED A BLEND OF THE
BIAS CORRECTED 12 UTC SUITE. IN REGARDS TO PRECIPITATION...WHILE
ISOLATED DIURNAL CONVECTION IS HARD TO RULE OUT ANY DAY UNDER
NORTHWEST FLOW...THE FAVORED PERIODS FOR PRECIPITATION ARE SATURDAY
WITH LEE SURFACE LOW PRESSURE AND AGAIN TUESDAY INTO WEDNESDAY AS
PACIFIC ENERGY CRESTS THE UPPER LEVEL INTERMOUNTAIN WEST RIDGE AND
PROPAGATES INTO THE NORTHERN PLAINS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 542 PM CDT WED AUG 7 2013
SCT/BKN LOW VFR CIGS WILL CONTINUE THROUGH THE TAF PERIOD UNDER A
NORTHWEST UPPER FLOW AND A COUPLE OF UPPER AIR DISTURBANCES
RESULTING IN A VCSH MENTION AT KISN/KMOT/KJMS. COULD BE PATCHY FOG
DEVELOPING FOR A SHORT PERIOD TOWARD 12Z THURSDAY AT KMOT. WILL
MONITOR SATELLITE AND SURFACE OBSERVATIONS BEFORE MENTIONING A
PREDOMINATE GROUP IN THE FORECAST.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KS
SHORT TERM...TWH
LONG TERM...AYD
AVIATION...KS
AREA FORECAST DISCUSSION
NWS BISMARCK ND
338 PM CDT WED AUG 7 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 338 PM CDT WED AUG 7 2013
CURRENTLY...A STRONG UPPER LEVEL JET AND A SHORTWAVE IMPULSE
TRACKING ACROSS SOUTHERN SASKATCHEWAN IS RESPONSIBLE FOR PRODUCING
SCATTERED SHOWERS FROM NORTHEAST MONTANA INTO NORTHWEST NORTH
DAKOTA. THE SHOWERS ARE EXPECTED TO TRACK EAST AND SOUTH ACROSS
THE AREA LATE THIS AFTERNOON AND THIS EVENING. SIMILAR TO THE
TRACK OF A SHORTWAVE YESTERDAY. THE MAIN DIFFERENCE IS THE
ATMOSPHERE IS MORE STABLE TODAY. HOWEVER...WITH A STRONG UPPER
LEVEL JET AND SHORTWAVE...WE CANNOT RULE OUT A FEW THUNDERSTORMS
THIS AFTERNOON AND EARLY EVENING...WITH SMALL HAIL AND GUSTY
WINDS. HOWEVER IN THE FORECAST WE LIMITED THE BEST CHANCES TO THE
NORTH LATE THIS AFTERNOON...AND WITH LIMITED INSTABILITY AND
CAPPING ALOFT...WE KEPT A MENTION OF SHOWERS WITH ONLY ISOLATED
THUNDERSTORMS. EXPECT PRECIPITATION CHANCES TO DIMINISH AS THE
SYSTEM TRACKS SOUTHEAST. BUT THE LATEST RAP AND HRRR HOLD
REFLECTIVITIES TOGETHER AS THEY TRACK INTO THE SOUTHEAST CWA
AROUND MIDNIGHT.
MODELS HAVE TRENDED FARTHER SOUTH WITH THE NEXT WAVE COMING INTO
THE AREA AFTER MIDNIGHT. HAVE THEREFORE CONTINUED THE TREND OF
LOWERING POPS ACROSS THE AREA. CURRENTLY HAVE CHANCE POPS ACROSS
THE FAR SOUTHWEST AND SOUTH CENTRAL LATE TONIGHT...AND HAVE
DROPPED POPS ACROSS THE SOUTH ON THURSDAY MORNING. ANOTHER
SHORTWAVE MOVING ACROSS ALBERTA TONIGHT WILL DROP SOUTHEAST INTO
THE LOCAL AREA THURSDAY AFTERNOON. THIS COULD DEVELOP AN ISOLATED
SHOWERS ACROSS THE NORTH DURING THE AFTERNOON. TEMPERATURES WILL
REMAIN ON THE COOL SIDE WITH HIGHS RANGING FROM THE 60S NORTH TO
THE 70S SOUTH.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 338 PM CDT WED AUG 7 2013
CONTINUED BELOW NORMAL TEMPERATURES WILL HIGHLIGHT THE EXTENDED
FORECAST.
AS HAS BEEN THE PATTERN OVER THE LAST COUPLE WEEKS...NORTHWEST
FLOW ALOFT WILL CONTINUE ACROSS THE NORTHERN PLAINS THROUGH THE
EXTENDED. THIS FAVORS BELOW NORMAL TEMPERATURES WITH HIGHS
GENERALLY IN THE 70S...PERHAPS RECOVERING INTO THE LOWER 80S BY
MID NEXT WEEK. OVERALL...THE COOLER EDGE OF GUIDANCE HAS BEEN
HANDLING THIS PATTERN BETTER...AND THUS UTILIZED A BLEND OF THE
BIAS CORRECTED 12 UTC SUITE. IN REGARDS TO PRECIPITATION...WHILE
ISOLATED DIURNAL CONVECTION IS HARD TO RULE OUT ANY DAY UNDER
NORTHWEST FLOW...THE FAVORED PERIODS FOR PRECIPITATION ARE SATURDAY
WITH LEE SURFACE LOW PRESSURE AND AGAIN TUESDAY INTO WEDNESDAY AS
PACIFIC ENERGY CRESTS THE UPPER LEVEL INTERMOUNTAIN WEST RIDGE AND
PROPAGATES INTO THE NORTHERN PLAINS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 338 PM CDT WED AUG 7 2013
OTHERWISE VFR CEILINGS EXPECTED THROUGH THE PERIOD. BROUGHT A
VCTS/VCSH ACROSS KISN KMOT AND KJMS THIS AFTERNOON AND THIS
EVENING. CONVECTION DEVELOPING LATER TONIGHT NOW APPEARS FARTHER
SOUTH SO DID NO INCLUDE THUNDER AT TAF SITES FOR THE SYSTEM LATE
TONIGHT INTO THURSDAY MORNING.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...TWH
LONG TERM...AYD
AVIATION...TWH
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1106 PM EDT THU AUG 8 2013
.SYNOPSIS...
A SLOW MOVING FRONTAL SYSTEM WILL PUSH SOUTHEAST TOWARD THE OHIO
RIVER TONIGHT AND FRIDAY. THE FRONT WILL CONTINUE TO PUSH FARTHER
SOUTH FRIDAY NIGHT INTO SATURDAY AS HIGH PRESSURE AND DRIER AIR
BEGIN TO BUILD INTO THE GREAT LAKES. IN THE MEANTIME...A MOIST
AIRMASS WILL ACCOMPANY THE FRONT WITH THE THREAT OF SHOWERS AND
THUNDERSTORMS...AND LOCALLY HEAVY RAINFALL...EXPECTED THROUGH
FRIDAY.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
ARES OF SHOWERS WERE SHOWING TRAINING ECHOS OVER PORTIONS OF
SOUTHEAST INDIANA. UPDATED THE FORECAST TO ACCOUNT FOR THE
CATEGORICAL NATURE OF THE SHOWERS AND THUNDERSTORMS IN THIS AREA
WITH AN EXPECTATION THAT THEY WILL PROGRESS TO THE EAST-SOUTHEAST
OVERNIGHT. TEMPERATURES AND DEWPOINTS WERE BLENDED WITH OBSERVED
VALUES AND WERE ON TRACK AS NEAR AS I COULD SEE.
WILL RELY ON THE RAP AND HRRR MODELS FOR THE NEAR TERM. AS
HELPFUL AS THE MODELS HAVE BEEN IN THE IMMEDIATE NEAR TERM...THE
EVOLUTION OF CONVECTION OVERNIGHT INTO FRIDAY MORNING CONTINUES TO
OSCILLATE WITH EACH SUCCESSIVE RUN...SO WILL DISCUSS THE UNCERTAINTIES
IN THE FORECAST.
EFFECTIVE FRONTAL BOUNDARY MAY HAVE SLID A LITTLE FARTHER SOUTH
THIS EVENING DUE TO RECENT CONVECTION AS SEEN ON MOSAIC RADAR.
THIS MAY PLAY A PART IN WHERE THE BEST COVERAGE OF SHOWERS AND
THUNDERSTORMS WILL OCCUR OVERNIGHT. CONVECTION CURRENTLY OVER THE
REGION HAS SHOWN A DOWNWARD TREND WITH THE DIURNAL CYCLE.
HOWEVER...AN UPTICK IS EXPECTED AGAIN LATER THIS EVENING AND
OVERNIGHT AS AN UPSTREAM MCV OVER SE ILLINOIS TRAVELS EAST THROUGH
THE OHIO VALLEY. ASSOCIATED SUBTLE LOW LEVEL JET/850 MB MOISTURE
TRANSPORT AND A WEAKLY REFLECTED SFC WAVE MAY ALLOW SHOWERS AND
THUNDERSTORMS TO BECOME MORE FOCUSED SOUTH OF THE DAYTON AND
COLUMBUS AREAS...IN OTHER WORDS...ALONG AND SOUTH OF THE OHIO
RIVER BASED ON LATEST MODEL RUNS. BUT GIVEN OSCILLATING SOLUTIONS
FROM RUN TO RUN...AM HESITANT AT THIS TIME TO CUT BUT THE FFA FOR THE
DAYTON AND COLUMBUS AREAS. SO WILL LET THIS HOLD AT THIS TIME BUT
MENTION THAT BETTER COVERAGE MAY BE CLOSER TO THE OHIO RIVER. THE
AIRMASS TONIGHT WILL BE VERY MOIST...PWATS IN EXCESS OF 2
INCHES...AND WARM CLOUD DEPTHS WILL BE FAVORABLE FOR
COLLISION/COALESCENCE PROCESSES. SO THE HEAVY RAIN THREAT WILL
CONTINUE...WITH RAINFALL RATES OF 1 TO 2 INCHES PER HOUR OR
PERHAPS IN SLIGHTLY LESSER TIMES GIVEN FAVORABLE ENVIRONMENT.
LOWS TONIGHT WILL RANGE FROM THE MID 60S FAR NW TO THE LOWER 70S
ALONG AND SOUTH OF THE OHIO RIVER.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
FRONTAL BOUNDARY WILL SLOWLY DROP SOUTHEAST TOWARD THE OHIO RIVER ON
FRIDAY...THEN SOUTH OF THE OHIO RIVER BY SATURDAY MORNING. HAVE
CONTINUED WITH A CHANCE OF SHOWERS AND THUNDERSTORMS...WITH LIKELY
POPS GIVEN TO LOCATIONS ALONG AND SOUTHEAST OF THE FRONT FRIDAY
AFTERNOON DUE TO DIURNAL HEATING AND ANY POSSIBLE DISTURBANCES
ALOFT PASSING BY. AGAIN...THE THREAT OF HEAVY RAIN WILL CONTINUE
AND THIS IS WHY THE 2 SEGMENT OF THE FFA WILL CONTINUE UNTIL 00Z
SATURDAY. INTENSITY AND COVERAGE OF PCPN SHOULD WANE FRIDAY NIGHT
AS THE ATMOSPHERE STABILIZES...AND FRONTAL CONVERGENCE SHIFTS
FARTHER SOUTH. DRIER AIR WILL BEGIN TO BUILD INTO THE NRN ZONES
FRIDAY NIGHT AS HIGH PRESSURE MOVES INTO THE GREAT LAKES REGION.
HIGHS ON FRIDAY WILL BE CLOUD AND PCPN DEPENDENT BUT SHOULD RANGE
FROM THE LOWER TO MID 80S. LOWS FRIDAY NIGHT WILL RANGE FROM THE
LOWER 60S NW TO THE UPPER 60S ALONG AND SOUTH OF THE OHIO RIVER.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
COLD FRONT MAY STILL BE LINGERING IN THE FAR SOUTHERN PART OF THE
FORECAST AREA AT THE BEGINNING OF THE PERIOD BEFORE FINALLY PUSHING
OFF TO THE SOUTH. SO KEPT CHANCE POPS INTO SATURDAY NEAR THIS
BOUNDARY. WENT SLIGHTLY BELOW MOS FOR HIGHS AND THEN LEANED TOWARDS
COOLER NAM GUIDANCE FOR SATURDAY NIGHT LOWS.
HIGH PRESSURE WILL BUILD IN SUNDAY AND MOVE OFF TO THE EAST ON
MONDAY. TEMPERATURES WILL BE NEAR NORMAL DURING THIS TIME FRAME. A
DEVELOPING UPPER TROUGH WILL PUSH A COLD FRONT INTO THE REGION
MONDAY NIGHT INTO TUESDAY. THIS WILL RESULT IN THE NEXT CHANCE OF
SHOWERS AND THUNDERSTORMS. RIDGING WILL RETURN WEDNESDAY AND
THURSDAY AS HIGH PRESSURE SETTLES OVER THE GREAT LAKES BRINGING
ANOTHER COOL AND DRY AIR MASS.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
WIND SHIFT HAS REACHED THROUGH KDAY AND APPEARS TO BE NEARING KCMH
AT TAF ISSUANCE TIME. SHOWERS AND ISOLD THUNDERSTORMS ARE WANING
IN STRENGTH BUT STILL COVER A GOOD BIT OF REAL ESTATE OVER SRN
OHIO THIS EVENING. IN THE SAME BREATH...KILN AND CENTRAL OHIO ARE
THE ONLY STATIONS THAT I AM KEEPING ANY ONGOING SHOWERS/TS AND
EXPECT KCMH/KLCK TO BE DONE IN THE NEXT HOUR OR TWO AS THE FRONT
MOVES EAST-SOUTHEAST.
UPSTREAM COMPLEX OVER SRN ILL APPEARS TO BE HANDLED FAIRLY WELL BY
THE 18Z NAM12. AFTER THESE STORMS AFFECT SW OHIO EARLY IN THE DAY
TOMORROW...THE FRONT WILL BE THROUGH MUCH OF THE CWA AND TAF
SITES...AND COULD SUPPORT MORE STORMS SOUTHEAST OF THE I-71
CORRIDOR IN THE LATE MORNING AND AFTERNOON. THIS IS SUPPORTED BY
BOTH THE GFS AND EUROPEAN WHICH HAVE LITTLE IF ANY PRECIP AT THE
TAFS IN THE 12Z-0Z TIME FRAME.
SOME IFR CLOUDS/VSBYS ARE EXPECTED TOWARDS DAYBREAK AT KDAY AND
KCMH/KLCK.
OUTLOOK...THUNDERSTORMS ARE POSSIBLE MONDAY NIGHT INTO TUESDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...FLASH FLOOD WATCH UNTIL 8 AM EDT FRIDAY FOR OHZ045-046-051>056-
060>065-070>072.
FLASH FLOOD WATCH THROUGH FRIDAY EVENING FOR OHZ073-074-
077>082-088.
KY...FLASH FLOOD WATCH THROUGH FRIDAY EVENING FOR KYZ089>100.
IN...FLASH FLOOD WATCH UNTIL 8 AM EDT FRIDAY FOR INZ050-058-059-066-
073-074.
FLASH FLOOD WATCH THROUGH FRIDAY EVENING FOR INZ075-080.
&&
$$
SYNOPSIS...HICKMAN
NEAR TERM...FRANKS/HICKMAN
SHORT TERM...HICKMAN
LONG TERM...
AVIATION...FRANKS/SITES
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
1016 PM EDT THU AUG 8 2013
.SYNOPSIS...
MOISTURE AND INSTABILITY PERSISTS INTO THE WEEKEND WITH ROUNDS OF
SHOWERS AND THUNDERSTORMS. COLD FRONT SAGS SLOWLY SOUTH THROUGH
VICINITY SATURDAY INTO SATURDAY NIGHT.
&&
.NEAR TERM /THROUGH FRIDAY/...
1015 PM UPDATE...
DECREASED POPS FURTHER THIS EVE MOST PLACES BASED ON RADAR
TRENDS...STILL KEEPING ISO COVERAGE WORDING THOUGH. HAVE SOME LKLY
IN N MTNS NEXT FEW HRS TO FOLLOW CONCENTRATION OF SHRA. STILL ON
TRACK FOR INCREASE IN SHRA TOWARD MORNING W HALF OF CWA.
745 PM UPDATE...
THINGS QUIETING DOWN THIS EVE WITH MOST OF THE SHRA CLOSER TO
FRONT IN OH. SOME SHRA NOTED TRAVERSING THRU THE MTNS AND
LOWLANDS. WITH HI RES MDLS NOT SHOWING MUCH THRU 06Z ASIDE FROM SE
OH...WILL DROP POPS MOST PLACES...GOING WITH MOSTLY ISO LATER THIS
EVE. THINK MORE SHRA IN THE CARDS...THOUGH...AS SFC FRONT TRIES
TO INCH S INTO PORTIONS OF SE OH. HRRR TRENDS BACK THIS UP WITH
SHRA MOVING BACK IN W HALF OF CWA AFTER 06Z.
PREVIOUS DISCUSSION BELOW...
ACTIVE WEATHER CONTINUES FOR THE NEAR TERM AND BEYOND...WITH THE
PRIMARY FORECAST CONCERN REVOLVING AROUND PRECIP AMOUNTS EXPECTED
ALONG WITH SUBSEQUENT FLOODING POTENTIAL.
AT 18Z RADAR DEPICTING A NORTH/SOUTH BROKEN LINE OF SHOWERS WITH
SOME THUNDER MOVING EASTWARD ACROSS THE CENTRAL PART OF THE FORECAST
AREA. SFC FRONT CURRENTLY LOCATED ROUGHLY JUST SOUTH OF CLEVELAND
OHIO W/SW-WARD TO JUST NORTH OF DAYTON OHIO...WITH EXPECTED
DEVELOPING SHOWERS/THUNDERSTORMS NEAR IT AS WELL. LINE OF SHOWERS
CURRENTLY BISECTING AREA WILL CONTINUE EAST INTO THE MOUNTAINS BY
LATE AFTERNOON...WITH SHOWERS/STORMS ON THE FRONT TO PUSH E/NE-WARD
AND EVENTUALLY MAKING INTO PARTS OF THE NW ZONES BY LATE
AFTERNOON/EARLY EVE. NOT EXPECTING MUCH IN THE WAY OF A SEVERE
THREAT WITH THESE STORMS FOR OUR AREA...BUT SIMILAR TO YESTERDAY...A
MARGINAL THREAT FOR A SEVERE STORM EXISTS MAINLY TO THE NORTH AND
NORTHWEST OF THE FORECAST AREA.
OVERNIGHT ANY ONGOING CONVECTION WILL CONTINUE TO SLIDE EASTWARD
MAINLY ACROSS NORTHERN ZONES WHILE DIMINISHING IN COVERAGE AND
STRENGTH AS INSTABILITY WANES. SHOULD SEE THE NORMAL LULL IN
OVERNIGHT PRECIP COVERAGE INITIALLY BUT WILL LEAVE LOW/MID CHANCE
POPS IN THE EARLY OVERNIGHT HOURS. BY AND AFTER 06Z THE NEXT IN THE
SERIES OF VORT MAXES APPROACHES THE WESTERN ZONES WITH SFC LOW
RIDING ALONG THE STALLED FRONT JUST TO THE NW OF THE AREA. TOUGH TO
KNOW HOW MUCH TO INCREASE POPS WITH THESE FEATURES BUT WILL BRING IN
HIGHER POPS ACROSS THE WEST QUICKER THAN THE USUAL DIURNAL
TREND...BY 09Z-12Z FRI. THIS VORT MAX QUICKLY PUSHES OFF TO THE EAST
WHILE BEING REPLACED BY A STRONGER VORT MAX PROGGED TO MOVE ACROSS
NORTHERN ZONES DURING THE AFTERNOON. AS SFC LOW CONTINUES TO PULL
AWAY TO THE NORTH THE COLD FRONT ATTEMPTS TO PUSH SOUTHEAST A BIT
AND FOR A TIME AFTER 18Z FRI-00Z SAT MAY BE LOCATED OVER OUR SE OHIO
ZONES. STILL EXPECT THE HIGHEST GENERAL COVERAGE OF PRECIP TO BE
NEAR AND OUT AHEAD OF THE VORT MAX BUT MAY SEE SOME REDEVELOPMENT
ALONG THE FRONT ITSELF FURTHER WEST.
REGARDING FLASH FLOODING POTENTIAL...THE GENERAL CONSENSUS OF PRECIP
MODEL OUTPUT RUNNING AROUND 1.00IN - 1.50IN. THE AREA IS AND HAS
BEEN MOSTLY DRY RECENTLY. WHILE NOT APPEARING TO BE A WIDESPREAD
FLOOD THREAT...WITH TALL STORMS AND PWATS AT AND OVER 2.00IN AND
STORM MOTION AROUND 10-15KTS...STORMS SHOULD BE GOOD RAINMAKERS.
WILL CONTINUE THE FLASH FLOOD WATCH MAINLY FOR THE POTENTIAL OF SOME
LOCALIZED FLASH FLOODING...WITH THE HIGHEST THREAT APPEARING TO COME
EARLY FRIDAY AT THIS POINT IN TIME.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
FRONTAL BOUNDARY STALLED OUT ALONG NORTHERN ZONES FRIDAY NIGHT...BUT
WILL SLOWLY SAG SOUTH ACROSS THE CWA ON SATURDAY...WITH A GRADUAL
DRYING TREND NORTH TO SOUTH AS IT DOES SO. KEPT HEAVY RAIN WORDING
INT HE FORECAST FOR FRIDAY NIGHT...AS PW VALUES ARE PROGGED TO STILL
BE OVER 2 INCHES. FRONTAL BOUNDARY WILL END UP TO THE SOUTH OF THE
CWA BY SUNDAY MORNING. WILL STILL BE A CHANCE FOR SOME SHOWER/STORM
ACTIVITY ALONG THE EXTREME SOUTHERN/EASTERN ZONES AS WAVES CONTINUE
TO PUSH EAST ACROSS THE FRONTAL BOUNDARY...BUT THE BULK OF THE CWA
SHOULD BE IN DRIER...AND SOMEWHAT COOLER WEATHER. AS WITH PREVIOUS
FORECAST...CONTINUED TO TREND MORE TOWARDS THE GFS/ECMWF SOLUNS
WHICH INDICATE A WAVE...AND THUS HIGHER POPS MOVING ACROSS
SOUTHERN/CENTRAL ZONES FRIDAY NIGHT/SATURDAY.
AS STATED PREVIOUSLY...THE FFA MAY BE ABLE TO BE TRIMMED EARLY
ACROSS THE NORTHERN ZONES FRIDAY NIGHT AS THIS FRONTAL BOUNDARY
STARTS TO SINK SOUTH ACROSS THE CWA.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
EXTENDED PERIOD STARTS OUT DRIER AS FRONTAL BOUNDARY TO THE SOUTH OF
THE CWA...AND HIGH PRESSURE BRIEFLY BUILDS IN FROM THE NORTH.
HOWEVER...MOISTURE AND HUMIDITY WILL BE ON THE INCREASE ONCE AGAIN
BY LATE MONDAY NIGHT INTO TUESDAY...AS A LOW PRESSURE SYSTEM...AND
COLD FRONTAL BOUNDARY APPROACH AND MOVE THROUGH THE AREA THROUGH MID
WEEK. INCREASED POPS TO AT LEAST CHANCE-HIGH CHANCE CATEGORY
EARLY-MID WEEK. COULD SEE HEAVY DOWNPOURS ASSOCIATED WITH ANY
SHOWERS/STORMS AS PW VALUES WILL ONCE AGAIN RISE UP TO AROUND
1.7-1.9 INCHES...AND DEPENDING ON WHAT HAPPENS OVER THE NEXT FEW
DAYS/INTO THE WEEKEND...COULD DETERMINE WHETHER OR NOT ANY LOCALIZED
WATER ISSUES WILL BE A CONCERN.
FRONTAL BOUNDARY SINKS TO THE SOUTH ON THURSDAY...WITH DRIER AND
COOLER WEATHER IN ITS WAKE.
&&
.AVIATION /02Z FRIDAY THROUGH TUESDAY/...
TOUGH AVIATION FCST FOR TONIGHT. BELIEVE SCT SHRA WILL WANE BY
03Z...SAVE ACROSS SE OH...CLOSER TO SFC FRONT. HAVE SOME TEMPO
MVFR GROUPS FOR SHRA KCRW AND KEKN NEXT COUPLE HRS BASED ON RADAR TRENDS.
DESPITE THE RAINS TODAY ACROSS MOST OF THE TERMINALS...A 20 KT
WIND ARND H925 COMBINED WITH LINGERING CLDS...SHOULD PREVENT IFR
OR WORSE FG TONIGHT. EXCEPTION MAY BE KEKN WHERE IFR VSBY WITH
LIFR CIGS EXPECTED. OTHERWISE WILL INTRODUCE SOME BKN MVFR STRATUS
IN TAFS FOR OVERNIGHT. AS SFC FRONT SLOWLY EDGES CLOSER TO SE
OH...SHRA MAY EXPAND IN COVERAGE INTO NE KY/W WV LATE TONIGHT AND
INTO THE MORNING HRS. EXPECT ANOTHER DAY OF SHRA AND AFTN TSRA
WITH FRONT MAKING TO OH RVR BY 00Z. MVFR CIGS FOR MOST PART
TOMORROW. KEPT VSBY IN VFR AT THIS DISTANCE THOUGH AND ALSO KEPT
THUNDER OUT OF TAFS UNTIL AFTN.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z SATURDAY...
FORECAST CONFIDENCE: LOW TO MEDIUM.
ALTERNATE SCENARIOS: TIMING OF FLIGHT CONDITIONS MAY BE HIGHLY
VARIABLE OVERNIGHT AND TOMORROW.
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 08/09/13
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 M M H H H H H H H H
HTS CONSISTENCY H H M H H H H H H M H H
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY M H M M H M M M M H H H
PKB CONSISTENCY H M M M H H H H H H H H
CKB CONSISTENCY M M H H H H H H H M M M
AFTER 00Z SATURDAY...
IFR POSSIBLE IN ROUNDS OF CONVECTION INTO SATURDAY NIGHT. IN HUMID
AIR IFR CEILINGS COULD EVEN DEVELOP OUTSIDE THE
CONVECTION...ESPECIALLY AT NIGHT AND INTO THE MORNING.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...FLASH FLOOD WATCH THROUGH LATE FRIDAY NIGHT FOR WVZ005>011-
013>020-024>040-046-047.
OH...FLASH FLOOD WATCH THROUGH LATE FRIDAY NIGHT FOR OHZ066-067-075-
076-083>087.
KY...FLASH FLOOD WATCH THROUGH LATE FRIDAY NIGHT FOR KYZ101>103-105.
VA...FLASH FLOOD WATCH THROUGH LATE FRIDAY NIGHT FOR VAZ003-004.
&&
$$
SYNOPSIS...50/SL
NEAR TERM...50/30
SHORT TERM...SL
LONG TERM...SL
AVIATION...30
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1000 PM EDT THU AUG 8 2013
.SYNOPSIS...
A SLOW MOVING FRONTAL SYSTEM WILL PUSH SOUTHEAST TOWARD THE OHIO
RIVER TONIGHT AND FRIDAY. THE FRONT WILL CONTINUE TO PUSH FARTHER
SOUTH FRIDAY NIGHT INTO SATURDAY AS HIGH PRESSURE AND DRIER AIR
BEGIN TO BUILD INTO THE GREAT LAKES. IN THE MEANTIME...A MOIST
AIRMASS WILL ACCOMPANY THE FRONT WITH THE THREAT OF SHOWERS AND
THUNDERSTORMS...AND LOCALLY HEAVY RAINFALL...EXPECTED THROUGH
FRIDAY.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
ARES OF SHOWERS WERE SHOWING TRAINING ECHOS OVER PORTIONS OF
SOUTHEAST INDIANA. UPDATED THE FORECAST TO ACCOUNT FOR THE
CATEGORICAL NATURE OF THE SHOWERS AND THUNDERSTORMS IN THIS AREA
WITH AN EXPECTATION THAT THEY WILL PROGRESS TO THE EAST-SOUTHEAST
OVERNIGHT. TEMPERATURES AND DEWPOINTS WERE BLENDED WITH OBSERVED
VALUES AND WERE ON TRACK AS NEAR AS I COULD SEE.
WILL RELY ON THE RAP AND HRRR MODELS FOR THE NEAR TERM. AS
HELPFUL AS THE MODELS HAVE BEEN IN THE IMMEDIATE NEAR TERM...THE
EVOLUTION OF CONVECTION OVERNIGHT INTO FRIDAY MORNING CONTINUES TO
OSCILLATE WITH EACH SUCCESSIVE RUN...SO WILL DISCUSS THE UNCERTAINTIES
IN THE FORECAST.
EFFECTIVE FRONTAL BOUNDARY MAY HAVE SLID A LITTLE FARTHER SOUTH
THIS EVENING DUE TO RECENT CONVECTION AS SEEN ON MOSAIC RADAR.
THIS MAY PLAY A PART IN WHERE THE BEST COVERAGE OF SHOWERS AND
THUNDERSTORMS WILL OCCUR OVERNIGHT. CONVECTION CURRENTLY OVER THE
REGION HAS SHOWN A DOWNWARD TREND WITH THE DIURNAL CYCLE.
HOWEVER...AN UPTICK IS EXPECTED AGAIN LATER THIS EVENING AND
OVERNIGHT AS AN UPSTREAM MCV OVER SE ILLINOIS TRAVELS EAST THROUGH
THE OHIO VALLEY. ASSOCIATED SUBTLE LOW LEVEL JET/850 MB MOISTURE
TRANSPORT AND A WEAKLY REFLECTED SFC WAVE MAY ALLOW SHOWERS AND
THUNDERSTORMS TO BECOME MORE FOCUSED SOUTH OF THE DAYTON AND
COLUMBUS AREAS...IN OTHER WORDS...ALONG AND SOUTH OF THE OHIO
RIVER BASED ON LATEST MODEL RUNS. BUT GIVEN OSCILLATING SOLUTIONS
FROM RUN TO RUN...AM PERSISTENT AT THIS TIME TO CUT BUT THE FFA FOR
THE DAYTON AND COLUMBUS AREAS. SO WILL LET THIS HOLD AT THIS TIME
BUT MENTION THAT BETTER COVERAGE MAY BE CLOSER TO THE OHIO RIVER.
THE AIRMASS TONIGHT WILL BE VERY MOIST...PWATS IN EXCESS OF 2
INCHES...AND WARM CLOUD DEPTHS WILL BE FAVORABLE FOR
COLLISION/COALESCENCE PROCESSES. SO THE HEAVY RAIN THREAT WILL
CONTINUE...WITH RAINFALL RATES OF 1 TO 2 INCHES PER HOUR OR
PERHAPS IN SLIGHTLY LESSER TIMES GIVEN FAVORABLE ENVIRONMENT.
LOWS TONIGHT WILL RANGE FROM THE MID 60S FAR NW TO THE LOWER 70S
ALONG AND SOUTH OF THE OHIO RIVER.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
FRONTAL BOUNDARY WILL SLOWLY DROP SOUTHEAST TOWARD THE OHIO RIVER ON
FRIDAY...THEN SOUTH OF THE OHIO RIVER BY SATURDAY MORNING. HAVE
CONTINUED WITH A CHANCE OF SHOWERS AND THUNDERSTORMS...WITH LIKELY
POPS GIVEN TO LOCATIONS ALONG AND SOUTHEAST OF THE FRONT FRIDAY
AFTERNOON DUE TO DIURNAL HEATING AND ANY POSSIBLE DISTURBANCES
ALOFT PASSING BY. AGAIN...THE THREAT OF HEAVY RAIN WILL CONTINUE
AND THIS IS WHY THE 2 SEGMENT OF THE FFA WILL CONTINUE UNTIL 00Z
SATURDAY. INTENSITY AND COVERAGE OF PCPN SHOULD WANE FRIDAY NIGHT
AS THE ATMOSPHERE STABILIZES...AND FRONTAL CONVERGENCE SHIFTS
FARTHER SOUTH. DRIER AIR WILL BEGIN TO BUILD INTO THE NRN ZONES
FRIDAY NIGHT AS HIGH PRESSURE MOVES INTO THE GREAT LAKES REGION.
HIGHS ON FRIDAY WILL BE CLOUD AND PCPN DEPENDENT BUT SHOULD RANGE
FROM THE LOWER TO MID 80S. LOWS FRIDAY NIGHT WILL RANGE FROM THE
LOWER 60S NW TO THE UPPER 60S ALONG AND SOUTH OF THE OHIO RIVER.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
COLD FRONT MAY STILL BE LINGERING IN THE FAR SOUTHERN PART OF THE
FORECAST AREA AT THE BEGINNING OF THE PERIOD BEFORE FINALLY PUSHING
OFF TO THE SOUTH. SO KEPT CHANCE POPS INTO SATURDAY NEAR THIS
BOUNDARY. WENT SLIGHTLY BELOW MOS FOR HIGHS AND THEN LEANED TOWARDS
COOLER NAM GUIDANCE FOR SATURDAY NIGHT LOWS.
HIGH PRESSURE WILL BUILD IN SUNDAY AND MOVE OFF TO THE EAST ON
MONDAY. TEMPERATURES WILL BE NEAR NORMAL DURING THIS TIME FRAME. A
DEVELOPING UPPER TROUGH WILL PUSH A COLD FRONT INTO THE REGION
MONDAY NIGHT INTO TUESDAY. THIS WILL RESULT IN THE NEXT CHANCE OF
SHOWERS AND THUNDERSTORMS. RIDGING WILL RETURN WEDNESDAY AND
THURSDAY AS HIGH PRESSURE SETTLES OVER THE GREAT LAKES BRINGING
ANOTHER COOL AND DRY AIR MASS.
&&
.AVIATION /02Z FRIDAY THROUGH TUESDAY/...
WIND SHIFT HAS REACHED THROUGH KDAY AND APPEARS TO BE NEARING KCMH
AT TAF ISSUANCE TIME. SHOWERS AND ISOLD THUNDERSTORMS ARE WANING
IN STRENGTH BUT STILL COVER A GOOD BIT OF REAL ESTATE OVER SRN
OHIO THIS EVENING. IN THE SAME BREATH...KILN AND CENTRAL OHIO ARE
THE ONLY STATIONS THAT I AM KEEPING ANY ONGOING SHOWERS/TS AND
EXPECT KCMH/KLCK TO BE DONE IN THE NEXT HOUR OR TWO AS THE FRONT
MOVES EAST-SOUTHEAST.
UPSTREAM COMPLEX OVER SRN ILL APPEARS TO BE HANDLED FAIRLY WELL BY
THE 18Z NAM12. AFTER THESE STORMS AFFECT SW OHIO EARLY IN THE DAY
TOMORROW...THE FRONT WILL BE THROUGH MUCH OF THE CWA AND TAF
SITES...AND COULD SUPPORT MORE STORMS SOUTHEAST OF THE I-71
CORRIDOR IN THE LATE MORNING AND AFTERNOON. THIS IS SUPPORTED BY
BOTH THE GFS AND EUROPEAN WHICH HAVE LITTLE IF ANY PRECIP AT THE
TAFS IN THE 12Z-0Z TIME FRAME.
SOME IFR CLOUDS/VSBYS ARE EXPECTED TOWARDS DAYBREAK AT KDAY AND
KCMH/KLCK.
OUTLOOK...THUNDERSTORMS ARE POSSIBLE MONDAY NIGHT INTO TUESDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...FLASH FLOOD WATCH UNTIL 8 AM EDT FRIDAY FOR OHZ042>046-051>056-
060>065-070>072.
FLASH FLOOD WATCH THROUGH FRIDAY EVENING FOR OHZ073-074-
077>082-088.
KY...FLASH FLOOD WATCH THROUGH FRIDAY EVENING FOR KYZ089>100.
IN...FLASH FLOOD WATCH UNTIL 8 AM EDT FRIDAY FOR INZ050-058-059-066-
073-074.
FLASH FLOOD WATCH THROUGH FRIDAY EVENING FOR INZ075-080.
&&
$$
SYNOPSIS...HICKMAN
NEAR TERM...FRANKS/HICKMAN
SHORT TERM...HICKMAN
LONG TERM...
AVIATION...FRANKS/SITES
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
800 PM EDT THU AUG 8 2013
.SYNOPSIS...
A SLOW MOVING FRONTAL SYSTEM WILL PUSH SOUTHEAST TOWARD THE OHIO
RIVER TONIGHT AND FRIDAY. THE FRONT WILL CONTINUE TO PUSH FARTHER
SOUTH FRIDAY NIGHT INTO SATURDAY AS HIGH PRESSURE AND DRIER AIR
BEGIN TO BUILD INTO THE GREAT LAKES. IN THE MEANTIME...A MOIST
AIRMASS WILL ACCOMPANY THE FRONT WITH THE THREAT OF SHOWERS AND
THUNDERSTORMS...AND LOCALLY HEAVY RAINFALL...EXPECTED THROUGH
FRIDAY.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
WILL RELY ON THE RAP AND HRRR MODELS FOR THE NEAR TERM. AS
HELPFUL AS THE MODELS HAVE BEEN IN THE IMMEDIATE NEAR TERM...THE
EVOLUTION OF CONVECTION OVERNIGHT INTO FRIDAY MORNING CONTINUES TO
OSCILLATE WITH EACH SUCCESSIVE RUN...SO WILL DISCUSS THE UNCERTAINTIES
IN THE FORECAST.
EFFECTIVE FRONTAL BOUNDARY MAY HAVE SLID A LITTLE FARTHER SOUTH
THIS EVENING DUE TO RECENT CONVECTION AS SEEN ON MOSAIC RADAR.
THIS MAY PLAY A PART IN WHERE THE BEST COVERAGE OF SHOWERS AND
THUNDERSTORMS WILL OCCUR OVERNIGHT. CONVECTION CURRENTLY OVER THE
REGION HAS SHOWN A DOWNWARD TREND WITH THE DIURNAL CYCLE.
HOWEVER...AN UPTICK IS EXPECTED AGAIN LATER THIS EVENING AND
OVERNIGHT AS AN UPSTREAM MCV OVER SE ILLINOIS TRAVELS EAST THROUGH
THE OHIO VALLEY. ASSOCIATED SUBTLE LOW LEVEL JET/850 MB MOISTURE
TRANSPORT AND A WEAKLY REFLECTED SFC WAVE MAY ALLOW SHOWERS AND
THUNDERSTORMS TO BECOME MORE FOCUSED SOUTH OF THE DAYTON AND
COLUMBUS AREAS...IN OTHER WORDS...ALONG AND SOUTH OF THE OHIO
RIVER BASED ON LATEST MODEL RUNS. BUT GIVEN OSCILLATING SOLUTIONS
FROM RUN TO RUN...AM PERSISTENT AT THIS TIME TO CUT BUT THE FFA FOR
THE DAYTON AND COLUMBUS AREAS. SO WILL LET THIS HOLD AT THIS TIME
BUT MENTION THAT BETTER COVERAGE MAY BE CLOSER TO THE OHIO RIVER.
THE AIRMASS TONIGHT WILL BE VERY MOIST...PWATS IN EXCESS OF 2
INCHES...AND WARM CLOUD DEPTHS WILL BE FAVORABLE FOR
COLLISION/COALESCENCE PROCESSES. SO THE HEAVY RAIN THREAT WILL
CONTINUE...WITH RAINFALL RATES OF 1 TO 2 INCHES PER HOUR OR
PERHAPS IN SLIGHTLY LESSER TIMES GIVEN FAVORABLE ENVIRONMENT.
LOWS TONIGHT WILL RANGE FROM THE MID 60S FAR NW TO THE LOWER 70S
ALONG AND SOUTH OF THE OHIO RIVER.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
FRONTAL BOUNDARY WILL SLOWLY DROP SOUTHEAST TOWARD THE OHIO RIVER ON
FRIDAY...THEN SOUTH OF THE OHIO RIVER BY SATURDAY MORNING. HAVE
CONTINUED WITH A CHANCE OF SHOWERS AND THUNDERSTORMS...WITH LIKELY
POPS GIVEN TO LOCATIONS ALONG AND SOUTHEAST OF THE FRONT FRIDAY
AFTERNOON DUE TO DIURNAL HEATING AND ANY POSSIBLE DISTURBANCES
ALOFT PASSING BY. AGAIN...THE THREAT OF HEAVY RAIN WILL CONTINUE
AND THIS IS WHY THE 2 SEGMENT OF THE FFA WILL CONTINUE UNTIL 00Z
SATURDAY. INTENSITY AND COVERAGE OF PCPN SHOULD WANE FRIDAY NIGHT
AS THE ATMOSPHERE STABILIZES...AND FRONTAL CONVERGENCE SHIFTS
FARTHER SOUTH. DRIER AIR WILL BEGIN TO BUILD INTO THE NRN ZONES
FRIDAY NIGHT AS HIGH PRESSURE MOVES INTO THE GREAT LAKES REGION.
HIGHS ON FRIDAY WILL BE CLOUD AND PCPN DEPENDENT BUT SHOULD RANGE
FROM THE LOWER TO MID 80S. LOWS FRIDAY NIGHT WILL RANGE FROM THE
LOWER 60S NW TO THE UPPER 60S ALONG AND SOUTH OF THE OHIO RIVER.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
COLD FRONT MAY STILL BE LINGERING IN THE FAR SOUTHERN PART OF THE
FORECAST AREA AT THE BEGINNING OF THE PERIOD BEFORE FINALLY PUSHING
OFF TO THE SOUTH. SO KEPT CHANCE POPS INTO SATURDAY NEAR THIS
BOUNDARY. WENT SLIGHTLY BELOW MOS FOR HIGHS AND THEN LEANED TOWARDS
COOLER NAM GUIDANCE FOR SATURDAY NIGHT LOWS.
HIGH PRESSURE WILL BUILD IN SUNDAY AND MOVE OFF TO THE EAST ON
MONDAY. TEMPERATURES WILL BE NEAR NORMAL DURING THIS TIME FRAME. A
DEVELOPING UPPER TROUGH WILL PUSH A COLD FRONT INTO THE REGION
MONDAY NIGHT INTO TUESDAY. THIS WILL RESULT IN THE NEXT CHANCE OF
SHOWERS AND THUNDERSTORMS. RIDGING WILL RETURN WEDNESDAY AND
THURSDAY AS HIGH PRESSURE SETTLES OVER THE GREAT LAKES BRINGING
ANOTHER COOL AND DRY AIR MASS.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
WIND SHIFT HAS REACHED THROUGH KDAY AND APPEARS TO BE NEARING KCMH
AT TAF ISSUANCE TIME. SHOWERS AND ISOLD THUNDERSTORMS ARE WANING
IN STRENGTH BUT STILL COVER A GOOD BIT OF REAL ESTATE OVER SRN
OHIO THIS EVENING. IN THE SAME BREATH...KILN AND CENTRAL OHIO ARE
THE ONLY STATIONS THAT I AM KEEPING ANY ONGOING SHOWERS/TS AND
EXPECT KCMH/KLCK TO BE DONE IN THE NEXT HOUR OR TWO AS THE FRONT
MOVES EAST-SOUTHEAST.
UPSTREAM COMPLEX OVER SRN ILL APPEARS TO BE HANDLED FAIRLY WELL BY
THE 18Z NAM12. AFTER THESE STORMS AFFECT SW OHIO EARLY IN THE DAY
TOMORROW...THE FRONT WILL BE THROUGH MUCH OF THE CWA AND TAF
SITES...AND COULD SUPPORT MORE STORMS SOUTHEAST OF THE I-71
CORRIDOR IN THE LATE MORNING AND AFTERNOON. THIS IS SUPPORTED BY
BOTH THE GFS AND EUROPEAN WHICH HAVE LITTLE IF ANY PRECIP AT THE
TAFS IN THE 12Z-0Z TIME FRAME.
SOME IFR CLOUDS/VSBYS ARE EXPECTED TOWARDS DAYBREAK AT KDAY AND
KCMH/KLCK.
OUTLOOK...THUNDERSTORMS ARE POSSIBLE MONDAY NIGHT INTO TUESDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...FLASH FLOOD WATCH THROUGH FRIDAY MORNING FOR OHZ042>046-
051>056-060>065-070>072.
FLASH FLOOD WATCH THROUGH FRIDAY EVENING FOR OHZ073-074-
077>082-088.
KY...FLASH FLOOD WATCH THROUGH FRIDAY EVENING FOR KYZ089>100.
IN...FLASH FLOOD WATCH THROUGH FRIDAY MORNING FOR INZ050-058-059-
066-073-074.
FLASH FLOOD WATCH THROUGH FRIDAY EVENING FOR INZ075-080.
&&
$$
SYNOPSIS...HICKMAN
NEAR TERM...HICKMAN
SHORT TERM...HICKMAN
LONG TERM...
AVIATION...FRANKS/SITES
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
756 PM EDT THU AUG 8 2013
.SYNOPSIS...
MOISTURE AND INSTABILITY PERSISTS INTO THE WEEKEND WITH ROUNDS OF
SHOWERS AND THUNDERSTORMS. COLD FRONT SAGS SLOWLY SOUTH THROUGH
VICINITY SATURDAY INTO SATURDAY NIGHT.
&&
.NEAR TERM /THROUGH FRIDAY/...
745 PM UPDATE...
THINGS QUIETING DOWN THIS EVE WITH MOST OF THE SHRA CLOSER TO
FRONT IN OH. SOME SHRA NOTED TRAVERSING THRU THE MTNS AND
LOWLANDS. WITH HI RES MDLS NOT SHOWING MUCH THRU 06Z ASIDE FROM SE
OH...WILL DROP POPS MOST PLACES...GOING WITH MOSTLY ISO LATER THIS
EVE. THINK MORE SHRA IN THE CARDS...THOUGH...AS SFC FRONT TRIES
TO INCH S INTO PORTIONS OF SE OH. HRRR TRENDS BACK THIS UP WITH
SHRA MOVING BACK IN W HALF OF CWA AFTER 06Z.
PREVIOUS DISCUSSION BELOW...
ACTIVE WEATHER CONTINUES FOR THE NEAR TERM AND BEYOND...WITH THE
PRIMARY FORECAST CONCERN REVOLVING AROUND PRECIP AMOUNTS EXPECTED
ALONG WITH SUBSEQUENT FLOODING POTENTIAL.
AT 18Z RADAR DEPICTING A NORTH/SOUTH BROKEN LINE OF SHOWERS WITH
SOME THUNDER MOVING EASTWARD ACROSS THE CENTRAL PART OF THE FORECAST
AREA. SFC FRONT CURRENTLY LOCATED ROUGHLY JUST SOUTH OF CLEVELAND
OHIO W/SW-WARD TO JUST NORTH OF DAYTON OHIO...WITH EXPECTED
DEVELOPING SHOWERS/THUNDERSTORMS NEAR IT AS WELL. LINE OF SHOWERS
CURRENTLY BISECTING AREA WILL CONTINUE EAST INTO THE MOUNTAINS BY
LATE AFTERNOON...WITH SHOWERS/STORMS ON THE FRONT TO PUSH E/NE-WARD
AND EVENTUALLY MAKING INTO PARTS OF THE NW ZONES BY LATE
AFTERNOON/EARLY EVE. NOT EXPECTING MUCH IN THE WAY OF A SEVERE
THREAT WITH THESE STORMS FOR OUR AREA...BUT SIMILAR TO YESTERDAY...A
MARGINAL THREAT FOR A SEVERE STORM EXISTS MAINLY TO THE NORTH AND
NORTHWEST OF THE FORECAST AREA.
OVERNIGHT ANY ONGOING CONVECTION WILL CONTINUE TO SLIDE EASTWARD
MAINLY ACROSS NORTHERN ZONES WHILE DIMINISHING IN COVERAGE AND
STRENGTH AS INSTABILITY WANES. SHOULD SEE THE NORMAL LULL IN
OVERNIGHT PRECIP COVERAGE INITIALLY BUT WILL LEAVE LOW/MID CHANCE
POPS IN THE EARLY OVERNIGHT HOURS. BY AND AFTER 06Z THE NEXT IN THE
SERIES OF VORT MAXES APPROACHES THE WESTERN ZONES WITH SFC LOW
RIDING ALONG THE STALLED FRONT JUST TO THE NW OF THE AREA. TOUGH TO
KNOW HOW MUCH TO INCREASE POPS WITH THESE FEATURES BUT WILL BRING IN
HIGHER POPS ACROSS THE WEST QUICKER THAN THE USUAL DIURNAL
TREND...BY 09Z-12Z FRI. THIS VORT MAX QUICKLY PUSHES OFF TO THE EAST
WHILE BEING REPLACED BY A STRONGER VORT MAX PROGGED TO MOVE ACROSS
NORTHERN ZONES DURING THE AFTERNOON. AS SFC LOW CONTINUES TO PULL
AWAY TO THE NORTH THE COLD FRONT ATTEMPTS TO PUSH SOUTHEAST A BIT
AND FOR A TIME AFTER 18Z FRI-00Z SAT MAY BE LOCATED OVER OUR SE OHIO
ZONES. STILL EXPECT THE HIGHEST GENERAL COVERAGE OF PRECIP TO BE
NEAR AND OUT AHEAD OF THE VORT MAX BUT MAY SEE SOME REDEVELOPMENT
ALONG THE FRONT ITSELF FURTHER WEST.
REGARDING FLASH FLOODING POTENTIAL...THE GENERAL CONSENSUS OF PRECIP
MODEL OUTPUT RUNNING AROUND 1.00IN - 1.50IN. THE AREA IS AND HAS
BEEN MOSTLY DRY RECENTLY. WHILE NOT APPEARING TO BE A WIDESPREAD
FLOOD THREAT...WITH TALL STORMS AND PWATS AT AND OVER 2.00IN AND
STORM MOTION AROUND 10-15KTS...STORMS SHOULD BE GOOD RAINMAKERS.
WILL CONTINUE THE FLASH FLOOD WATCH MAINLY FOR THE POTENTIAL OF SOME
LOCALIZED FLASH FLOODING...WITH THE HIGHEST THREAT APPEARING TO COME
EARLY FRIDAY AT THIS POINT IN TIME.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
FRONTAL BOUNDARY STALLED OUT ALONG NORTHERN ZONES FRIDAY NIGHT...BUT
WILL SLOWLY SAG SOUTH ACROSS THE CWA ON SATURDAY...WITH A GRADUAL
DRYING TREND NORTH TO SOUTH AS IT DOES SO. KEPT HEAVY RAIN WORDING
INT HE FORECAST FOR FRIDAY NIGHT...AS PW VALUES ARE PROGGED TO STILL
BE OVER 2 INCHES. FRONTAL BOUNDARY WILL END UP TO THE SOUTH OF THE
CWA BY SUNDAY MORNING. WILL STILL BE A CHANCE FOR SOME SHOWER/STORM
ACTIVITY ALONG THE EXTREME SOUTHERN/EASTERN ZONES AS WAVES CONTINUE
TO PUSH EAST ACROSS THE FRONTAL BOUNDARY...BUT THE BULK OF THE CWA
SHOULD BE IN DRIER...AND SOMEWHAT COOLER WEATHER. AS WITH PREVIOUS
FORECAST...CONTINUED TO TREND MORE TOWARDS THE GFS/ECMWF SOLUNS
WHICH INDICATE A WAVE...AND THUS HIGHER POPS MOVING ACROSS
SOUTHERN/CENTRAL ZONES FRIDAY NIGHT/SATURDAY.
AS STATED PREVIOUSLY...THE FFA MAY BE ABLE TO BE TRIMMED EARLY
ACROSS THE NORTHERN ZONES FRIDAY NIGHT AS THIS FRONTAL BOUNDARY
STARTS TO SINK SOUTH ACROSS THE CWA.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
EXTENDED PERIOD STARTS OUT DRIER AS FRONTAL BOUNDARY TO THE SOUTH OF
THE CWA...AND HIGH PRESSURE BRIEFLY BUILDS IN FROM THE NORTH.
HOWEVER...MOISTURE AND HUMIDITY WILL BE ON THE INCREASE ONCE AGAIN
BY LATE MONDAY NIGHT INTO TUESDAY...AS A LOW PRESSURE SYSTEM...AND
COLD FRONTAL BOUNDARY APPROACH AND MOVE THROUGH THE AREA THROUGH MID
WEEK. INCREASED POPS TO AT LEAST CHANCE-HIGH CHANCE CATEGORY
EARLY-MID WEEK. COULD SEE HEAVY DOWNPOURS ASSOCIATED WITH ANY
SHOWERS/STORMS AS PW VALUES WILL ONCE AGAIN RISE UP TO AROUND
1.7-1.9 INCHES...AND DEPENDING ON WHAT HAPPENS OVER THE NEXT FEW
DAYS/INTO THE WEEKEND...COULD DETERMINE WHETHER OR NOT ANY LOCALIZED
WATER ISSUES WILL BE A CONCERN.
FRONTAL BOUNDARY SINKS TO THE SOUTH ON THURSDAY...WITH DRIER AND
COOLER WEATHER IN ITS WAKE.
&&
.AVIATION /23Z THURSDAY THROUGH TUESDAY/...
TOUGH AVIATION FCST FOR TONIGHT. BELIEVE SCT SHRA WILL WANE BY
03Z...SAVE ACROSS SE OH...CLOSER TO SFC FRONT. HAVE SOME TEMPO
MVFR GROUPS FOR SHRA KCRW AND KEKN NEXT COUPLE HRS BASED ON RADAR TRENDS.
DESPITE THE RAINS TODAY ACROSS MOST OF THE TERMINALS...A 20 KT
WIND ARND H925 COMBINED WITH LINGERING CLDS...SHOULD PREVENT IFR
OR WORSE FG TONIGHT. EXCEPTION MAY BE KEKN WHERE IFR VSBY WITH
LIFR CIGS EXPECTED. OTHERWISE WILL INTRODUCE SOME BKN MVFR STRATUS
IN TAFS FOR OVERNIGHT. AS SFC FRONT SLOWLY EDGES CLOSER TO SE
OH...SHRA MAY EXPAND IN COVERAGE INTO NE KY/W WV LATE TONIGHT AND
INTO THE MORNING HRS. EXPECT ANOTHER DAY OF SHRA AND AFTN TSRA
WITH FRONT MAKING TO OH RVR BY 00Z. MVFR CIGS FOR MOST PART
TOMORROW. KEPT VSBY IN VFR AT THIS DISTANCE THOUGH AND ALSO KEPT
THUNDER OUT OF TAFS UNTIL AFTN.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z SATURDAY...
FORECAST CONFIDENCE: LOW TO MEDIUM.
ALTERNATE SCENARIOS: TIMING OF FLIGHT CONDITIONS MAY BE HIGHLY
VARIABLE OVERNIGHT AND TOMORROW.
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 08/09/13
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 H H M M M H M L L L L L
HTS CONSISTENCY H H H H H H H H H H L L
BKW CONSISTENCY H H H H H H H M H H H H
EKN CONSISTENCY M M M H M M H M M M M H
PKB CONSISTENCY H H M M M M H H M H H H
CKB CONSISTENCY M M M M H H H H H H H H
AFTER 00Z SATURDAY...
IFR POSSIBLE IN ROUNDS OF CONVECTION INTO SATURDAY NIGHT. IN HUMID
AIR IFR CEILINGS COULD EVEN DEVELOP OUTSIDE THE
CONVECTION...ESPECIALLY AT NIGHT AND INTO THE MORNING.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...FLASH FLOOD WATCH THROUGH LATE FRIDAY NIGHT FOR WVZ005>011-
013>020-024>040-046-047.
OH...FLASH FLOOD WATCH THROUGH LATE FRIDAY NIGHT FOR OHZ066-067-075-
076-083>087.
KY...FLASH FLOOD WATCH THROUGH LATE FRIDAY NIGHT FOR KYZ101>103-105.
VA...FLASH FLOOD WATCH THROUGH LATE FRIDAY NIGHT FOR VAZ003-004.
&&
$$
SYNOPSIS...50/SL
NEAR TERM...50/30
SHORT TERM...SL
LONG TERM...SL
AVIATION...30
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
711 PM EDT THU AUG 8 2013
.SYNOPSIS...
A SLOW MOVING FRONTAL SYSTEM WILL PUSH SOUTHEAST TOWARD THE OHIO
RIVER TONIGHT AND FRIDAY. THE FRONT WILL CONTINUE TO PUSH FARTHER
SOUTH FRIDAY NIGHT INTO SATURDAY AS HIGH PRESSURE AND DRIER AIR
BEGIN TO BUILD INTO THE GREAT LAKES. IN THE MEANTIME...A MOIST
AIRMASS WILL ACCOMPANY THE FRONT WITH THE THREAT OF SHOWERS AND
THUNDERSTORMS...AND LOCALLY HEAVY RAINFALL...EXPECTED THROUGH
FRIDAY.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
WILL RELY ON THE RAP AND HRRR MODELS FOR THE NEAR TERM. AS
HELPFUL AS THE MODELS HAVE BEEN IN THE IMMEDIATE NEAR TERM...THE
EVOLUTION OF CONVECTION OVERNIGHT INTO FRIDAY MORNING CONTINUES TO
OSCILLATE WITH EACH SUCCESSIVE RUN...SO WILL DISCUSS THE UNCERTAINTIES
IN THE FORECAST.
EFFECTIVE FRONTAL BOUNDARY MAY HAVE SLID A LITTLE FARTHER SOUTH
THIS EVENING DUE TO RECENT CONVECTION AS SEEN ON MOSAIC RADAR.
THIS MAY PLAY A PART IN WHERE THE BEST COVERAGE OF SHOWERS AND
THUNDERSTORMS WILL OCCUR OVERNIGHT. CONVECTION CURRENTLY OVER THE
REGION HAS SHOWN A DOWNWARD TREND WITH THE DIURNAL CYCLE.
HOWEVER...AN UPTICK IS EXPECTED AGAIN LATER THIS EVENING AND
OVERNIGHT AS AN UPSTREAM MCV OVER SE ILLINOIS TRAVELS EAST THROUGH
THE OHIO VALLEY. ASSOCIATED SUBTLE LOW LEVEL JET/850 MB MOISTURE
TRANSPORT AND A WEAKLY REFLECTED SFC WAVE MAY ALLOW SHOWERS AND
THUNDERSTORMS TO BECOME MORE FOCUSED SOUTH OF THE DAYTON AND
COLUMBUS AREAS...IN OTHER WORDS...ALONG AND SOUTH OF THE OHIO
RIVER BASED ON LATEST MODEL RUNS. BUT GIVEN OSCILLATING SOLUTIONS
FROM RUN TO RUN...AM PERSISTENT AT THIS TIME TO CUT BUT THE FFA FOR
THE DAYTON AND COLUMBUS AREAS. SO WILL LET THIS HOLD AT THIS TIME
BUT MENTION THAT BETTER COVERAGE MAY BE CLOSER TO THE OHIO RIVER.
THE AIRMASS TONIGHT WILL BE VERY MOIST...PWATS IN EXCESS OF 2
INCHES...AND WARM CLOUD DEPTHS WILL BE FAVORABLE FOR
COLLISION/COALESCENCE PROCESSES. SO THE HEAVY RAIN THREAT WILL
CONTINUE...WITH RAINFALL RATES OF 1 TO 2 INCHES PER HOUR OR
PERHAPS IN SLIGHTLY LESSER TIMES GIVEN FAVORABLE ENVIRONMENT.
LOWS TONIGHT WILL RANGE FROM THE MID 60S FAR NW TO THE LOWER 70S
ALONG AND SOUTH OF THE OHIO RIVER.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
FRONTAL BOUNDARY WILL SLOWLY DROP SOUTHEAST TOWARD THE OHIO RIVER ON
FRIDAY...THEN SOUTH OF THE OHIO RIVER BY SATURDAY MORNING. HAVE
CONTINUED WITH A CHANCE OF SHOWERS AND THUNDERSTORMS...WITH LIKELY
POPS GIVEN TO LOCATIONS ALONG AND SOUTHEAST OF THE FRONT FRIDAY
AFTERNOON DUE TO DIURNAL HEATING AND ANY POSSIBLE DISTURBANCES
ALOFT PASSING BY. AGAIN...THE THREAT OF HEAVY RAIN WILL CONTINUE
AND THIS IS WHY THE 2 SEGMENT OF THE FFA WILL CONTINUE UNTIL 00Z
SATURDAY. INTENSITY AND COVERAGE OF PCPN SHOULD WANE FRIDAY NIGHT
AS THE ATMOSPHERE STABILIZES...AND FRONTAL CONVERGENCE SHIFTS
FARTHER SOUTH. DRIER AIR WILL BEGIN TO BUILD INTO THE NRN ZONES
FRIDAY NIGHT AS HIGH PRESSURE MOVES INTO THE GREAT LAKES REGION.
HIGHS ON FRIDAY WILL BE CLOUD AND PCPN DEPENDENT BUT SHOULD RANGE
FROM THE LOWER TO MID 80S. LOWS FRIDAY NIGHT WILL RANGE FROM THE
LOWER 60S NW TO THE UPPER 60S ALONG AND SOUTH OF THE OHIO RIVER.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
COLD FRONT MAY STILL BE LINGERING IN THE FAR SOUTHERN PART OF THE
FORECAST AREA AT THE BEGINNING OF THE PERIOD BEFORE FINALLY PUSHING
OFF TO THE SOUTH. SO KEPT CHANCE POPS INTO SATURDAY NEAR THIS
BOUNDARY. WENT SLIGHTLY BELOW MOS FOR HIGHS AND THEN LEANED TOWARDS
COOLER NAM GUIDANCE FOR SATURDAY NIGHT LOWS.
HIGH PRESSURE WILL BUILD IN SUNDAY AND MOVE OFF TO THE EAST ON
MONDAY. TEMPERATURES WILL BE NEAR NORMAL DURING THIS TIME FRAME. A
DEVELOPING UPPER TROUGH WILL PUSH A COLD FRONT INTO THE REGION
MONDAY NIGHT INTO TUESDAY. THIS WILL RESULT IN THE NEXT CHANCE OF
SHOWERS AND THUNDERSTORMS. RIDGING WILL RETURN WEDNESDAY AND
THURSDAY AS HIGH PRESSURE SETTLES OVER THE GREAT LAKES BRINGING
ANOTHER COOL AND DRY AIR MASS.
&&
.AVIATION /23Z THURSDAY THROUGH TUESDAY/...
MODERATELY UNSTABLE ATMOSPHERE HAS ACTIVATED AHEAD OF THE CDFNT
WORKING INTO THE REGION. EXPECT CONVECTION TO CONTINUE INTO THE
EVENING WITH THE WEAK FRONTAL CONVERGENCE AND BOUNDARIES ACTING AS
FORCING.
LOOKING TOWARDS OVERNIGHT HOURS...AFT 02Z..,GETTING A WHOLE BUNCH
OF DIFFERENT ANSWERS FROM THE MODELS. SYSTEM OUT OVER MO ATTM
HEADS EAST. MODELS ARE SHOWING DIFFERENT TIMING AND TRACK OF THE
SYSTEM HAS IT APPROACHES THE AREA. THE NAM WEAKENS AND SHUNTS THE
SYSTEM S OF THE TAFS...KEEPING THINGS PRETTY DRY ON FRIDAY. THE 2
CMC MODELS ALONG WITH THE ECMWF BRING IT IN TOWARDS 12Z AND GIVE THE
SRN TAFS THE BEST CHC OF PCPN. THE GFS MEANWHILE LIFTS SI UP RIGHT
ACROSS THE FA ON FRIDAY. LEANED TOWARDS THE MAJORITY FORECAST AND
BROUGHT VCTS/VCSH INTO THE KCVG/KLUK AROUND 09Z. ALSO ABOUT THIS
TIME REDEVELOPED THE FOG AND STRATUS AGAIN. THIS FAR OUT DID NOT
HAVE THE CONFIDENCE TO GO IFR...ESPECIALLY IF WE GET A LOT OF
MIXING FROM PCPN.
THREW A VCSH AT KDAY AND KILN AFT 15Z AS HEATING OF THE ATMOSPHERE
MAY ALLOW CONVECTION TO INITIATE AGAIN AFTER ST BEGINS TO LIFT.
OUTLOOK...THUNDERSTORMS WILL CONTINUE TO BE POSSIBLE AT TIMES
THROUGH FRIDAY....THEN AGAIN MONDAY NIGHT INTO TUESDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...FLASH FLOOD WATCH THROUGH FRIDAY MORNING FOR OHZ042>046-
051>056-060>065-070>072.
FLASH FLOOD WATCH THROUGH FRIDAY EVENING FOR OHZ073-074-
077>082-088.
KY...FLASH FLOOD WATCH THROUGH FRIDAY EVENING FOR KYZ089>100.
IN...FLASH FLOOD WATCH THROUGH FRIDAY MORNING FOR INZ050-058-059-
066-073-074.
FLASH FLOOD WATCH THROUGH FRIDAY EVENING FOR INZ075-080.
&&
$$
SYNOPSIS...HICKMAN
NEAR TERM...HICKMAN
SHORT TERM...HICKMAN
LONG TERM...
AVIATION...SITES
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
900 AM EDT WED AUG 7 2013
.SYNOPSIS...
MOISTURE AND INSTABILITY INCREASING TODAY. WE REMAIN IN MUGGY
UNSTABLE ENVIRONMENT INTO WEEKEND WITH ROUNDS OF CONVECTION.
COLD FRONT SAGS SLOWLY SOUTH THROUGH VICINITY SATURDAY INTO SUNDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
MORNING UPDATE...MADE SOME VERY MINOR CHANGES TO THE AERIAL EXTENT
OF THE SCATTERED SHOWER AND ISOLATED THUNDERSTORM COVERAGE THIS
MORNING BASED ON THE LOCATION OF ACCAS AS WELL AS THE CONVECTION
IN EASTERN KENTUCKY. ASIDE FROM THESE TWO FEATURES MUCH OF THE
AFTERNOON STORMS WILL BE OF THE HEATING GENERATED AIR MASS VARIETY
SO STUCK WITH THE TREND OF BROADENING CHANCE POPS AND LIKELIES
SPREADING IN FROM THE SOUTH AND WEST.
PREVIOUS DISCUSSION...DIFFICULT NEAR TERM FORECAST ON THIS
GRAVEYARD SHIFT...IN THESE WANING DOG DAYS OF SUMMER.
THERE HAS BEEN SOME LOW LEVEL FORCING GOING ON DURING THESE EARLY
MORNING HOURS...WITH A FASTER 925 MB FLOW OBSERVED ON VAD WINDS AT
ILN AND JKL COMPARED TO RLX. CLOUDS HAVE BEEN FORMING OVERNIGHT
WITH A FEW SHOWERS DEVELOPING ON RADAR.
THE MID LEVEL FLOW IS REMAINING WNW...WHICH SHOULD STEER ONE MAXIMUM
IN PCPN TODAY INTO TONIGHT FROM SOGGY WATERLOGGED MISSOURI INTO KY
INTO TN. A FEW DAYS AGO WE FIGURED ON MORE OF A WSW FLOW TODAY.
SO LOWERED POPS IN THE SOUTH TODAY A BIT...BUT STILL REACH INTO
THE 60 PERCENT LIKELY RANGE FOR THIS AFTN. MORE ATTENTION WILL
HAVE TO BE GIVEN TO WEAK 500 MB DISTURBANCES MOVING UP THE OHIO
VALLEY TODAY. 07Z RAP HAS ONE IN SOUTHERN OHIO AROUND 17Z. SO WILL
STILL TRY TO DEVELOP CONVECTION 16 TO 18Z AND MOVE EAST INTO OUR
OHIO VALLEY COUNTIES. WILL ALSO HAVE LIKELY POPS THERE. THIS
LEAVES NORTH CENTRAL WV WITH MORE UNCERTAINTY...WILL GO IN THE 40 TO
50 PERCENT RANGE THERE TODAY.
PRECIPITABLE WATER HAS INCREASED INTO THE 1.5 TO 1.75 INCHES FOR
TODAY. EQUILIBRIUM LEVEL 35 THSD THIS AFTERNOON. SO SHOWERS COULD
BE LOCALLY HEAVY...BUT WITH RECENT DRY DAYS...WILL REMOVE THE FLASH
FLOOD THREAT FOR TODAY AND TONIGHT IN THE HAZARDOUS WEATHER
POTENTIAL. HOWEVER...THE FLASH FLOOD THREAT WILL REMAIN IN THE SHORT
TERM PERIOD.
WITH DEW POINTS ON EITHER SIDE OF 70...SOME HAZE MAY BE NOTED
OUTSIDE OF THE CONVECTION. WITH MORE CLOUDS...CONTINUED OUR MAXIMUM
TEMPERATURES BELOW GFS MOS GUIDANCE.
A MUGGY AUGUST NIGHT TONIGHT. WILL ONLY DROP POPS DOWN TO AROUND 40
PERCENT FOR THE LATE NIGHT HOURS. CAN NOT RULE OUT CONVECTION AT ANY
TIME.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
SOME UNCERTAINTY WITH SHORT TERM FORECAST AS MODELS CONTINUE TO
OFFER DIFFERING SOLUTIONS ON TIMING OF BEST POPS. APPEARS COLD FRONT
WILL RUN FROM ROUGHLY CLE-IND AT THE START OF THE SHORT TERM
PERIOD...AND WILL TAKE ITS SWEET TIME DROPPING SOUTH WITH NO REAL
UPPER LEVEL PUSH TO HELP IT OUT. MODELS STRUGGLING WITH TIMING ON
SURFACE WAVE MOVING ALONG THE FRONT...BUT THEY DO ALL SHOW SOMETHING
THURSDAY OR FRIDAY. HEDGED TOWARDS THE NAM...AS IT HAS BEEN FAIRLY
CONSISTENT AND ALSO HAS THE SUPPORT OF THE ECMWF ON THE FRONT
MOVEMENT...ALTHOUGH NOT NECESSARILY THE SMALLER SCALE WAVE. WITH
THIS THINKING...HAVE LIKELY POPS ACROSS WESTERN CWA WITH A 500MB
VORT MAX IN OHIO THURSDAY. ALSO HAVE MORE DIURNAL DRIVEN LIKELY POPS
ACROSS THE MOUNTAINS THURSDAY...CLOSER TO THE BETTER MOISTURE. NAM
THEN SHOWS A SURFACE WAVE RIDING UP THE FRONT FRIDAY AFTERNOON AND
EVENING...SO ANOTHER ROUND OF LIKELY POPS WITH THAT...LINGERING INTO
FRIDAY NIGHT WITH COLD FRONT IN THE VICINITY. EXPECT THERE TO BE
BREAKS BETWEEN THE ROUNDS OF LIKELY POPS...BUT WITH UNCERTAINTY ON
TIMING...ONLY DROPPED INTO LOW CHANCE DURING THESE BREAKS. NAM SHOWS
THE COLD FRONT MOVING THROUGH FRIDAY NIGHT OR EARLY SATURDAY
MORNING...HOWEVER ECMWF AND GFS ARE SLOWER...AND REALLY DO NOT EVEN
SINK IT ALL THE WAY THROUGH CWA BEFORE STALLING. TEND TO BELIEVE IN
A SLOWER SOLUTION...SO WILL KEEP CHANCE POPS EVERYWHERE EXCEPT
EXTREME NORTHERN CWA ON SATURDAY. EXPECT LOTS OF CLOUD COVER
THROUGHOUT THE SHORT TERM...AND ONLY MINOR CHANGES MADE TO HIGH AND
LOW TEMPERATURES. MAIN CHANGE WAS TO INCREASE LOWS FRIDAY NIGHT WITH
SLOWER FRONT.
CAN NOT RULE OUT ISOLATED WATER CONCERNS ON THURSDAY WITH PWAT
VALUES OF 1.5 TO 1.75 INCHES. FORTUNATELY...THE GROUND IS FAIRLY DRY
RIGHT NOW SO WILL TAKE SOME TIME TO SATURATE...AND ANTICIPATE IF WE
SEE PROBLEMS ON THURSDAY IT WILL BE ON THE ISOLATED SIDE. CONCERNS
ABOUT WATER INCREASE FOR FRIDAY HOWEVER. AS THE SURFACE WAVE
APPROACHES FROM THE SOUTHWEST...GOOD MOISTURE INFLOW WILL SPIKE
PWATS INTO THE 2 TO 2.5 INCH RANGE BY FRIDAY AFTERNOON. ALSO...FLOW
IS MORE PARALLEL TO THE FRONT ON FRIDAY SO SOME TRAINING MAY OCCUR.
WILL CONTINUE MENTION IN HWO FOR THURSDAY THROUGH SATURDAY.
&&
.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
GENERALLY USED WPC THINKING FOR THIS PORTION OF THE FORECAST.
HOWEVER...TRIMMED POPS FOR LATE IN THE PERIOD AS I THOUGHT THEY WERE TOO
HIGH...BASED ON THE WPC DAYS 4-7 SFC PROGS.
WPC INDICATES AN AREA OF LOW PRESSURE SHOULD BE LOCATED JUST TO OUR
WEST WITH A FRONT EXTENDING EAST-WEST ACROSS OUR FORECAST AREA. THE
LOW SHOULD MOVE SOUTHEAST ON SUNDAY...DRAGGING A COLD FRONT WITH
IT.
BY MONDAY MORNING...SFC LOW SHOULD BE LOCATED JUST OFF THE EAST
COAST WITH THE FRONT TO OUR SOUTH AND EAST. THIS BOUNDARY IS
EXPECTED TO MOVE LITTLE THROUGH THE REMAINDER OF OUR PERIOD.
MODELS SUGGEST SEVERAL SHORTWAVES WILL PUSH EAST/SOUTHEAST WITH
TIME. WITH FRONT TO OUR SOUTHEAST...EXPECT THESE FEATURES MAY BE
SUFFICIENT FOR A FEW SHOWERS/STORMS ACROSS OUR SOUTH AND EAST MONDAY
INTO WEDNESDAY.
&&
.AVIATION /13Z WEDNESDAY THROUGH SUNDAY/...
PATCHY CLOUDS AND ISOLATED SHOWER DID FORM 06Z TO 10Z...KEEPING VSBY
MOSTLY AOA 5 MILES.
THE QUESTIONS FOR TODAY...IS THE COVERAGE OF THE LOWER CUMULUS AND
THE TIMING THE ROUNDS OF CONVECTION. CONFIDENCE IS LOW ON TIMING
THE CONVECTION. IN THE 12Z SET OF TAFS WILL UP THE TIME AN HOUR OR
TWO FOR THE COVERAGE OF SHOWERS AND THUNDERSTORMS INCREASING IN THE
TRI STATE AROUND HTS AND SOUTHERN WEST VIRGINIA INTO SOUTHWEST
VIRGINIA DURING THE 15Z TO 18Z TIME FRAME...THEN MOVING EAST 18Z
WEDNESDAY TO 00Z THURSDAY. COVERAGE OF CONVECTION PKB TO CKB
DIFFICULT TO FIGURE BUT HAVE POPS MAXING OUT THERE BETWEEN 18Z TO
00Z.
QUESTIONS AGAIN ARISE ON WHAT HAPPENS TO THE CEILINGS 00Z TO 06Z
THURSDAY AND THE COVERAGE OF THE CONVECTION...THINKING THE 2 TO 3
THSD FT AGL CLOUDS WILL BE SCATTERED TO BROKEN. STILL CHANCE POPS
THROUGHOUT THE NIGHT IN THE MUGGY ENVIRONMENT.
VSBY WISE...A LOT OF 6 MILES IN HAZE OUTSIDE OF CONVECTION DURING
THE DAYLIGHT HOURS...LOWERING TO 4 MILES IN LIGHT FOG 00Z TO 06Z
THURSDAY AND REMAINING MOSTLY MVFR F BECAUSE OF CLOUDS COVER.
VSBY AOB 3 MILES IN CONVECTION.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z THURSDAY...
FORECAST CONFIDENCE: LOW.
ALTERNATE SCENARIOS: TIMING AND COVERAGE OF CONVECTION COULD VARY.
THE CUMULUS CEILINGS MAY SCATTER OUT IN PLACES LATE TODAY AND
THIS EVENING...LEAVING CEILING AT HIGHER LAYERS THAN FORECAST.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 11 12 13 14 15 16 17 18 19 20 21 22
EDT 1HRLY 07 08 09 10 11 12 13 14 15 16 17 18
CRW CONSISTENCY M M M H H H M M M M M M
HTS CONSISTENCY H H H H H M M M M M M M
BKW CONSISTENCY M M M M H M M M M M M M
EKN CONSISTENCY M M M M M H H H M M M M
PKB CONSISTENCY M M M H M M M M M M M M
CKB CONSISTENCY M M M H H H M M M M M M
AFTER 12Z THURSDAY...
IFR POSSIBLE IN ROUNDS OF CONVECTION INTO SATURDAY NIGHT. IN HUMID AIR
IFR CEILINGS COULD EVEN DEVELOP OUTSIDE THE CONVECTION...ESPECIALLY
AT NIGHT AND INTO THE MORNING.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...KTB/MZ
NEAR TERM...KTB/JR
SHORT TERM...MZ
LONG TERM...JSH
AVIATION...KTB
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
851 AM EDT WED AUG 7 2013
.SYNOPSIS...
MOISTURE AND INSTABILITY INCREASING TODAY. WE REMAIN IN MUGGY
UNSTABLE ENVIRONMENT INTO WEEKEND WITH ROUNDS OF CONVECTION.
COLD FRONT SAGS SLOWLY SOUTH THROUGH VICINITY SATURDAY INTO SUNDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
DIFFICULT NEAR TERM FORECAST ON THIS GRAVEYARD SHIFT...IN THESE
WANING DOG DAYS OF SUMMER.
THERE HAS BEEN SOME LOW LEVEL FORCING GOING ON DURING THESE EARLY
MORNING HOURS...WITH A FASTER 925 MB FLOW OBSERVED ON VAD WINDS AT
ILN AND JKL COMPARED TO RLX. CLOUDS HAVE BEEN FORMING OVERNIGHT
WITH A FEW SHOWERS DEVELOPING ON RADAR.
THE MID LEVEL FLOW IS REMAINING WNW...WHICH SHOULD STEER ONE MAXIMUM
IN PCPN TODAY INTO TONIGHT FROM SOGGY WATERLOGGED MISSOURI INTO KY
INTO TN. A FEW DAYS AGO WE FIGURED ON MORE OF A WSW FLOW TODAY.
SO LOWERED POPS IN THE SOUTH TODAY A BIT...BUT STILL REACH INTO
THE 60 PERCENT LIKELY RANGE FOR THIS AFTN. MORE ATTENTION WILL
HAVE TO BE GIVEN TO WEAK 500 MB DISTURBANCES MOVING UP THE OHIO
VALLEY TODAY. 07Z RAP HAS ONE IN SOUTHERN OHIO AROUND 17Z. SO WILL
STILL TRY TO DEVELOP CONVECTION 16 TO 18Z AND MOVE EAST INTO OUR
OHIO VALLEY COUNTIES. WILL ALSO HAVE LIKELY POPS THERE. THIS
LEAVES NORTH CENTRAL WV WITH MORE UNCERTAINTY...WILL GO IN THE 40 TO
50 PERCENT RANGE THERE TODAY.
PRECIPITABLE WATER HAS INCREASED INTO THE 1.5 TO 1.75 INCHES FOR
TODAY. EQUILIBRIUM LEVEL 35 THSD THIS AFTERNOON. SO SHOWERS COULD
BE LOCALLY HEAVY...BUT WITH RECENT DRY DAYS...WILL REMOVE THE FLASH
FLOOD THREAT FOR TODAY AND TONIGHT IN THE HAZARDOUS WEATHER
POTENTIAL. HOWEVER...THE FLASH FLOOD THREAT WILL REMAIN IN THE SHORT
TERM PERIOD.
WITH DEW POINTS ON EITHER SIDE OF 70...SOME HAZE MAY BE NOTED
OUTSIDE OF THE CONVECTION. WITH MORE CLOUDS...CONTINUED OUR MAXIMUM
TEMPERATURES BELOW GFS MOS GUIDANCE.
A MUGGY AUGUST NIGHT TONIGHT. WILL ONLY DROP POPS DOWN TO AROUND 40
PERCENT FOR THE LATE NIGHT HOURS. CAN NOT RULE OUT CONVECTION AT ANY
TIME.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
SOME UNCERTAINTY WITH SHORT TERM FORECAST AS MODELS CONTINUE TO
OFFER DIFFERING SOLUTIONS ON TIMING OF BEST POPS. APPEARS COLD FRONT
WILL RUN FROM ROUGHLY CLE-IND AT THE START OF THE SHORT TERM
PERIOD...AND WILL TAKE ITS SWEET TIME DROPPING SOUTH WITH NO REAL
UPPER LEVEL PUSH TO HELP IT OUT. MODELS STRUGGLING WITH TIMING ON
SURFACE WAVE MOVING ALONG THE FRONT...BUT THEY DO ALL SHOW SOMETHING
THURSDAY OR FRIDAY. HEDGED TOWARDS THE NAM...AS IT HAS BEEN FAIRLY
CONSISTENT AND ALSO HAS THE SUPPORT OF THE ECMWF ON THE FRONT
MOVEMENT...ALTHOUGH NOT NECESSARILY THE SMALLER SCALE WAVE. WITH
THIS THINKING...HAVE LIKELY POPS ACROSS WESTERN CWA WITH A 500MB
VORT MAX IN OHIO THURSDAY. ALSO HAVE MORE DIURNAL DRIVEN LIKELY POPS
ACROSS THE MOUNTAINS THURSDAY...CLOSER TO THE BETTER MOISTURE. NAM
THEN SHOWS A SURFACE WAVE RIDING UP THE FRONT FRIDAY AFTERNOON AND
EVENING...SO ANOTHER ROUND OF LIKELY POPS WITH THAT...LINGERING INTO
FRIDAY NIGHT WITH COLD FRONT IN THE VICINITY. EXPECT THERE TO BE
BREAKS BETWEEN THE ROUNDS OF LIKELY POPS...BUT WITH UNCERTAINTY ON
TIMING...ONLY DROPPED INTO LOW CHANCE DURING THESE BREAKS. NAM SHOWS
THE COLD FRONT MOVING THROUGH FRIDAY NIGHT OR EARLY SATURDAY
MORNING...HOWEVER ECMWF AND GFS ARE SLOWER...AND REALLY DO NOT EVEN
SINK IT ALL THE WAY THROUGH CWA BEFORE STALLING. TEND TO BELIEVE IN
A SLOWER SOLUTION...SO WILL KEEP CHANCE POPS EVERYWHERE EXCEPT
EXTREME NORTHERN CWA ON SATURDAY. EXPECT LOTS OF CLOUD COVER
THROUGHOUT THE SHORT TERM...AND ONLY MINOR CHANGES MADE TO HIGH AND
LOW TEMPERATURES. MAIN CHANGE WAS TO INCREASE LOWS FRIDAY NIGHT WITH
SLOWER FRONT.
CAN NOT RULE OUT ISOLATED WATER CONCERNS ON THURSDAY WITH PWAT
VALUES OF 1.5 TO 1.75 INCHES. FORTUNATELY...THE GROUND IS FAIRLY DRY
RIGHT NOW SO WILL TAKE SOME TIME TO SATURATE...AND ANTICIPATE IF WE
SEE PROBLEMS ON THURSDAY IT WILL BE ON THE ISOLATED SIDE. CONCERNS
ABOUT WATER INCREASE FOR FRIDAY HOWEVER. AS THE SURFACE WAVE
APPROACHES FROM THE SOUTHWEST...GOOD MOISTURE INFLOW WILL SPIKE
PWATS INTO THE 2 TO 2.5 INCH RANGE BY FRIDAY AFTERNOON. ALSO...FLOW
IS MORE PARALLEL TO THE FRONT ON FRIDAY SO SOME TRAINING MAY OCCUR.
WILL CONTINUE MENTION IN HWO FOR THURSDAY THROUGH SATURDAY.
&&
.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
GENERALLY USED WPC THINKING FOR THIS PORTION OF THE FORECAST.
HOWEVER...TRIMMED POPS FOR LATE IN THE PERIOD AS I THOUGHT THEY WERE TOO
HIGH...BASED ON THE WPC DAYS 4-7 SFC PROGS.
WPC INDICATES AN AREA OF LOW PRESSURE SHOULD BE LOCATED JUST TO OUR
WEST WITH A FRONT EXTENDING EAST-WEST ACROSS OUR FORECAST AREA. THE
LOW SHOULD MOVE SOUTHEAST ON SUNDAY...DRAGGING A COLD FRONT WITH
IT.
BY MONDAY MORNING...SFC LOW SHOULD BE LOCATED JUST OFF THE EAST
COAST WITH THE FRONT TO OUR SOUTH AND EAST. THIS BOUNDARY IS
EXPECTED TO MOVE LITTLE THROUGH THE REMAINDER OF OUR PERIOD.
MODELS SUGGEST SEVERAL SHORTWAVES WILL PUSH EAST/SOUTHEAST WITH
TIME. WITH FRONT TO OUR SOUTHEAST...EXPECT THESE FEATURES MAY BE
SUFFICIENT FOR A FEW SHOWERS/STORMS ACROSS OUR SOUTH AND EAST MONDAY
INTO WEDNESDAY.
&&
.AVIATION /13Z WEDNESDAY THROUGH SUNDAY/...
PATCHY CLOUDS AND ISOLATED SHOWER DID FORM 06Z TO 10Z...KEEPING VSBY
MOSTLY AOA 5 MILES.
THE QUESTIONS FOR TODAY...IS THE COVERAGE OF THE LOWER CUMULUS AND
THE TIMING THE ROUNDS OF CONVECTION. CONFIDENCE IS LOW ON TIMING
THE CONVECTION. IN THE 12Z SET OF TAFS WILL UP THE TIME AN HOUR OR
TWO FOR THE COVERAGE OF SHOWERS AND THUNDERSTORMS INCREASING IN THE
TRI STATE AROUND HTS AND SOUTHERN WEST VIRGINIA INTO SOUTHWEST
VIRGINIA DURING THE 15Z TO 18Z TIME FRAME...THEN MOVING EAST 18Z
WEDNESDAY TO 00Z THURSDAY. COVERAGE OF CONVECTION PKB TO CKB
DIFFICULT TO FIGURE BUT HAVE POPS MAXING OUT THERE BETWEEN 18Z TO
00Z.
QUESTIONS AGAIN ARISE ON WHAT HAPPENS TO THE CEILINGS 00Z TO 06Z
THURSDAY AND THE COVERAGE OF THE CONVECTION...THINKING THE 2 TO 3
THSD FT AGL CLOUDS WILL BE SCATTERED TO BROKEN. STILL CHANCE POPS
THROUGHOUT THE NIGHT IN THE MUGGY ENVIRONMENT.
VSBY WISE...A LOT OF 6 MILES IN HAZE OUTSIDE OF CONVECTION DURING
THE DAYLIGHT HOURS...LOWERING TO 4 MILES IN LIGHT FOG 00Z TO 06Z
THURSDAY AND REMAINING MOSTLY MVFR F BECAUSE OF CLOUDS COVER.
VSBY AOB 3 MILES IN CONVECTION.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z THURSDAY...
FORECAST CONFIDENCE: LOW.
ALTERNATE SCENARIOS: TIMING AND COVERAGE OF CONVECTION COULD VARY.
THE CUMULUS CEILINGS MAY SCATTER OUT IN PLACES LATE TODAY AND
THIS EVENING...LEAVING CEILING AT HIGHER LAYERS THAN FORECAST.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 11 12 13 14 15 16 17 18 19 20 21 22
EDT 1HRLY 07 08 09 10 11 12 13 14 15 16 17 18
CRW CONSISTENCY M M M H H H M M M M M M
HTS CONSISTENCY H H H H H M M M M M M M
BKW CONSISTENCY M M M M H M M M M M M M
EKN CONSISTENCY M M M M M H H H M M M M
PKB CONSISTENCY M M M H M M M M M M M M
CKB CONSISTENCY M M M H H H M M M M M M
AFTER 12Z THURSDAY...
IFR POSSIBLE IN ROUNDS OF CONVECTION INTO SATURDAY NIGHT. IN HUMID AIR
IFR CEILINGS COULD EVEN DEVELOP OUTSIDE THE CONVECTION...ESPECIALLY
AT NIGHT AND INTO THE MORNING.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...KTB/MZ
NEAR TERM...KTB
SHORT TERM...MZ
LONG TERM...JSH
AVIATION...KTB
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
621 AM EDT WED AUG 7 2013
.SYNOPSIS...
MOISTURE AND INSTABILITY INCREASING TODAY. WE REMAIN IN MUGGY
UNSTABLE ENVIRONMENT INTO WEEKEND WITH ROUNDS OF CONVECTION.
COLD FRONT SAGS SLOWLY SOUTH THROUGH VICINITY SATURDAY INTO SUNDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
DIFFICULT NEAR TERM FORECAST ON THIS GRAVEYARD SHIFT...IN THESE
WANING DOG DAYS OF SUMMER.
THERE HAS BEEN SOME LOW LEVEL FORCING GOING ON DURING THESE EARLY
MORNING HOURS...WITH A FASTER 925 MB FLOW OBSERVED ON VAD WINDS AT
ILN AND JKL COMPARED TO RLX. CLOUDS HAVE BEEN FORMING OVERNIGHT
WITH A FEW SHOWERS DEVELOPING ON RADAR.
THE MID LEVEL FLOW IS REMAINING WNW...WHICH SHOULD STEER ONE MAXIMUM
IN PCPN TODAY INTO TONIGHT FROM SOGGY WATERLOGGED MISSOURI INTO KY
INTO TN. A FEW DAYS AGO WE FIGURED ON MORE OF A WSW FLOW TODAY.
SO LOWERED POPS IN THE SOUTH TODAY A BIT...BUT STILL REACH INTO
THE 60 PERCENT LIKELY RANGE FOR THIS AFTN. MORE ATTENTION WILL
HAVE TO BE GIVEN TO WEAK 500 MB DISTURBANCES MOVING UP THE OHIO
VALLEY TODAY. 07Z RAP HAS ONE IN SOUTHERN OHIO AROUND 17Z. SO WILL
STILL TRY TO DEVELOP CONVECTION 16 TO 18Z AND MOVE EAST INTO OUR
OHIO VALLEY COUNTIES. WILL ALSO HAVE LIKELY POPS THERE. THIS
LEAVES NORTH CENTRAL WV WITH MORE UNCERTAINTY...WILL GO IN THE 40 TO
50 PERCENT RANGE THERE TODAY.
PRECIPITABLE WATER HAS INCREASED INTO THE 1.5 TO 1.75 INCHES FOR
TODAY. EQUILIBRIUM LEVEL 35 THSD THIS AFTERNOON. SO SHOWERS COULD
BE LOCALLY HEAVY...BUT WITH RECENT DRY DAYS...WILL REMOVE THE FLASH
FLOOD THREAT FOR TODAY AND TONIGHT IN THE HAZARDOUS WEATHER
POTENTIAL. HOWEVER...THE FLASH FLOOD THREAT WILL REMAIN IN THE SHORT
TERM PERIOD.
WITH DEW POINTS ON EITHER SIDE OF 70...SOME HAZE MAY BE NOTED
OUTSIDE OF THE CONVECTION. WITH MORE CLOUDS...CONTINUED OUR MAXIMUM
TEMPERATURES BELOW GFS MOS GUIDANCE.
A MUGGY AUGUST NIGHT TONIGHT. WILL ONLY DROP POPS DOWN TO AROUND 40
PERCENT FOR THE LATE NIGHT HOURS. CAN NOT RULE OUT CONVECTION AT ANY
TIME.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
SOME UNCERTAINTY WITH SHORT TERM FORECAST AS MODELS CONTINUE TO
OFFER DIFFERING SOLUTIONS ON TIMING OF BEST POPS. APPEARS COLD FRONT
WILL RUN FROM ROUGHLY CLE-IND AT THE START OF THE SHORT TERM
PERIOD...AND WILL TAKE ITS SWEET TIME DROPPING SOUTH WITH NO REAL
UPPER LEVEL PUSH TO HELP IT OUT. MODELS STRUGGLING WITH TIMING ON
SURFACE WAVE MOVING ALONG THE FRONT...BUT THEY DO ALL SHOW SOMETHING
THURSDAY OR FRIDAY. HEDGED TOWARDS THE NAM...AS IT HAS BEEN FAIRLY
CONSISTENT AND ALSO HAS THE SUPPORT OF THE ECMWF ON THE FRONT
MOVEMENT...ALTHOUGH NOT NECESSARILY THE SMALLER SCALE WAVE. WITH
THIS THINKING...HAVE LIKELY POPS ACROSS WESTERN CWA WITH A 500MB
VORT MAX IN OHIO THURSDAY. ALSO HAVE MORE DIURNAL DRIVEN LIKELY POPS
ACROSS THE MOUNTAINS THURSDAY...CLOSER TO THE BETTER MOISTURE. NAM
THEN SHOWS A SURFACE WAVE RIDING UP THE FRONT FRIDAY AFTERNOON AND
EVENING...SO ANOTHER ROUND OF LIKELY POPS WITH THAT...LINGERING INTO
FRIDAY NIGHT WITH COLD FRONT IN THE VICINITY. EXPECT THERE TO BE
BREAKS BETWEEN THE ROUNDS OF LIKELY POPS...BUT WITH UNCERTAINTY ON
TIMING...ONLY DROPPED INTO LOW CHANCE DURING THESE BREAKS. NAM SHOWS
THE COLD FRONT MOVING THROUGH FRIDAY NIGHT OR EARLY SATURDAY
MORNING...HOWEVER ECMWF AND GFS ARE SLOWER...AND REALLY DO NOT EVEN
SINK IT ALL THE WAY THROUGH CWA BEFORE STALLING. TEND TO BELIEVE IN
A SLOWER SOLUTION...SO WILL KEEP CHANCE POPS EVERYWHERE EXCEPT
EXTREME NORTHERN CWA ON SATURDAY. EXPECT LOTS OF CLOUD COVER
THROUGHOUT THE SHORT TERM...AND ONLY MINOR CHANGES MADE TO HIGH AND
LOW TEMPERATURES. MAIN CHANGE WAS TO INCREASE LOWS FRIDAY NIGHT WITH
SLOWER FRONT.
CAN NOT RULE OUT ISOLATED WATER CONCERNS ON THURSDAY WITH PWAT
VALUES OF 1.5 TO 1.75 INCHES. FORTUNATELY...THE GROUND IS FAIRLY DRY
RIGHT NOW SO WILL TAKE SOME TIME TO SATURATE...AND ANTICIPATE IF WE
SEE PROBLEMS ON THURSDAY IT WILL BE ON THE ISOLATED SIDE. CONCERNS
ABOUT WATER INCREASE FOR FRIDAY HOWEVER. AS THE SURFACE WAVE
APPROACHES FROM THE SOUTHWEST...GOOD MOISTURE INFLOW WILL SPIKE
PWATS INTO THE 2 TO 2.5 INCH RANGE BY FRIDAY AFTERNOON. ALSO...FLOW
IS MORE PARALLEL TO THE FRONT ON FRIDAY SO SOME TRAINING MAY OCCUR.
WILL CONTINUE MENTION IN HWO FOR THURSDAY THROUGH SATURDAY.
&&
.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
GENERALLY USED WPC THINKING FOR THIS PORTION OF THE FORECAST.
HOWEVER...HAVE MADE SOME CHANGES TO REFLECT DIFFERENCES IN LATEST
MODEL GUIDANCE.
WPC INDICATES A COLD FRONT SHOULD BE LOCATED JUST TO OUR NORTHWEST
EARLY IN THE PERIOD...SLOWLY SINKING SOUTH. SEVERAL MID-LEVEL
SHORTWAVES AND A WEAK AREA OF LOW PRESSURE WILL THEN PUSH EAST
MONDAY INTO TUESDAY.
LATEST GFS IS SLOWER WITH THE SOUTHEAST PROGRESS OF THE COLD
FRONT. WITH THIS IN MIND...HAVE HELD ONTO LOW POPS A LITTLE LONGER
FOR SATURDAY NIGHT INTO SUNDAY.
LOWERED HPC TEMP NUMBERS A FEW DEGREES AS THEY APPEAR TOO WARM FOR
THE EXPECTED CONDITIONS.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
PATCHY CLOUDS AND ISOLATED SHOWER DID FORM 06Z TO 10Z...KEEPING VSBY
MOSTLY AOA 5 MILES.
THE QUESTIONS FOR TODAY...IS THE COVERAGE OF THE LOWER CUMULUS AND
THE TIMING THE ROUNDS OF CONVECTION. CONFIDENCE IS LOW ON TIMING
THE CONVECTION. IN THE 12Z SET OF TAFS WILL UP THE TIME AN HOUR OR
TWO FOR THE COVERAGE OF SHOWERS AND THUNDERSTORMS INCREASING IN THE
TRI STATE AROUND HTS AND SOUTHERN WEST VIRGINIA INTO SOUTHWEST
VIRGINIA DURING THE 15Z TO 18Z TIME FRAME...THEN MOVING EAST 18Z
WEDNESDAY TO 00Z THURSDAY. COVERAGE OF CONVECTION PKB TO CKB
DIFFICULT TO FIGURE BUT HAVE POPS MAXING OUT THERE BETWEEN 18Z TO
00Z.
QUESTIONS AGAIN ARISE ON WHAT HAPPENS TO THE CEILINGS 00Z TO 06Z
THURSDAY AND THE COVERAGE OF THE CONVECTION...THINKING THE 2 TO 3
THSD FT AGL CLOUDS WILL BE SCATTERED TO BROKEN. STILL CHANCE POPS
THROUGHOUT THE NIGHT IN THE MUGGY ENVIRONMENT.
VSBY WISE...A LOT OF 6 MILES IN HAZE OUTSIDE OF CONVECTION DURING
THE DAYLIGHT HOURS...LOWERING TO 4 MILES IN LIGHT FOG 00Z TO 06Z
THURSDAY AND REMAINING MOSTLY MVFR F BECAUSE OF CLOUDS COVER.
VSBY AOB 3 MILES IN CONVECTION.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z THURSDAY...
FORECAST CONFIDENCE: LOW.
ALTERNATE SCENARIOS: TIMING AND COVERAGE OF CONVECTION COULD VARY.
THE CUMULUS CEILINGS MAY SCATTER OUT IN PLACES LATE TODAY AND
THIS EVENING...LEAVING CEILING AT HIGHER LAYERS THAN FORECAST.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 11 12 13 14 15 16 17 18 19 20 21 22
EDT 1HRLY 07 08 09 10 11 12 13 14 15 16 17 18
CRW CONSISTENCY M M M H H H M M M M M M
HTS CONSISTENCY H H H H H M M M M M M M
BKW CONSISTENCY M M M M H M M M M M M M
EKN CONSISTENCY M M M M M H H H M M M M
PKB CONSISTENCY M M M H M M M M M M M M
CKB CONSISTENCY M M M H H H M M M M M M
AFTER 12Z THURSDAY...
IFR POSSIBLE IN ROUNDS OF CONVECTION INTO SATURDAY NIGHT. IN HUMID AIR
IFR CEILINGS COULD EVEN DEVELOP OUTSIDE THE CONVECTION...ESPECIALLY
AT NIGHT AND INTO THE MORNING.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...KTB/MZ
NEAR TERM...MZ
SHORT TERM...MZ
LONG TERM...JSH
AVIATION...KTB
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
343 AM EDT WED AUG 7 2013
.SYNOPSIS...
MOISTURE AND INSTABILITY INCREASING TODAY. WE REMAIN IN MUGGY
UNSTABLE ENVIRONMENT INTO WEEKEND WITH ROUNDS OF CONVECTION.
COLD FRONT SAGS SLOWLY SOUTH THROUGH VICINITY SATURDAY INTO SUNDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
DIFFICULT NEAR TERM FORECAST ON THIS GRAVEYARD SHIFT...IN THESE
WANING DOG DAYS OF SUMMER.
THERE HAS BEEN SOME LOW LEVEL FORCING GOING ON DURING THESE EARLY
MORNING HOURS...WITH A FASTER 925 MB FLOW OBSERVED ON VAD WINDS AT
ILN AND JKL COMPARED TO RLX. CLOUDS HAVE BEEN FORMING OVERNIGHT
WITH A FEW SHOWERS DEVELOPING ON RADAR.
THE MID LEVEL FLOW IS REMAINING WNW...WHICH SHOULD STEER ONE MAXIMUM
IN PCPN TODAY INTO TONIGHT FROM SOGGY WATERLOGGED MISSOURI INTO KY
INTO TN. A FEW DAYS AGO WE FIGURED ON MORE OF A WSW FLOW TODAY.
SO LOWERED POPS IN THE SOUTH TODAY A BIT...BUT STILL REACH INTO
THE 60 PERCENT LIKELY RANGE FOR THIS AFTN. MORE ATTENTION WILL
HAVE TO BE GIVEN TO WEAK 500 MB DISTURBANCES MOVING UP THE OHIO
VALLEY TODAY. 07Z RAP HAS ONE IN SOUTHERN OHIO AROUND 17Z. SO WILL
STILL TRY TO DEVELOP CONVECTION 16 TO 18Z AND MOVE EAST INTO OUR
OHIO VALLEY COUNTIES. WILL ALSO HAVE LIKELY POPS THERE. THIS
LEAVES NORTH CENTRAL WV WITH MORE UNCERTAINTY...WILL GO IN THE 40 TO
50 PERCENT RANGE THERE TODAY.
PRECIPITABLE WATER HAS INCREASED INTO THE 1.5 TO 1.75 INCHES FOR
TODAY. EQUILIBRIUM LEVEL 35 THSD THIS AFTERNOON. SO SHOWERS COULD
BE LOCALLY HEAVY...BUT WITH RECENT DRY DAYS...WILL REMOVE THE FLASH
FLOOD THREAT FOR TODAY AND TONIGHT IN THE HAZARDOUS WEATHER
POTENTIAL. HOWEVER...THE FLASH FLOOD THREAT WILL REMAIN IN THE SHORT
TERM PERIOD.
WITH DEW POINTS ON EITHER SIDE OF 70...SOME HAZE MAY BE NOTED
OUTSIDE OF THE CONVECTION. WITH MORE CLOUDS...CONTINUED OUR MAXIMUM
TEMPERATURES BELOW GFS MOS GUIDANCE.
A MUGGY AUGUST NIGHT TONIGHT. WILL ONLY DROP POPS DOWN TO AROUND 40
PERCENT FOR THE LATE NIGHT HOURS. CAN NOT RULE OUT CONVECTION AT ANY
TIME.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
SOME UNCERTAINTY WITH SHORT TERM FORECAST AS MODELS CONTINUE TO
OFFER DIFFERING SOLUTIONS ON TIMING OF BEST POPS. APPEARS COLD FRONT
WILL RUN FROM ROUGHLY CLE-IND AT THE START OF THE SHORT TERM
PERIOD...AND WILL TAKE ITS SWEET TIME DROPPING SOUTH WITH NO REAL
UPPER LEVEL PUSH TO HELP IT OUT. MODELS STRUGGLING WITH TIMING ON
SURFACE WAVE MOVING ALONG THE FRONT...BUT THEY DO ALL SHOW SOMETHING
THURSDAY OR FRIDAY. HEDGED TOWARDS THE NAM...AS IT HAS BEEN FAIRLY
CONSISTENT AND ALSO HAS THE SUPPORT OF THE ECMWF ON THE FRONT
MOVEMENT...ALTHOUGH NOT NECESSARILY THE SMALLER SCALE WAVE. WITH
THIS THINKING...HAVE LIKELY POPS ACROSS WESTERN CWA WITH A 500MB
VORT MAX IN OHIO THURSDAY. ALSO HAVE MORE DIURNAL DRIVEN LIKELY POPS
ACROSS THE MOUNTAINS THURSDAY...CLOSER TO THE BETTER MOISTURE. NAM
THEN SHOWS A SURFACE WAVE RIDING UP THE FRONT FRIDAY AFTERNOON AND
EVENING...SO ANOTHER ROUND OF LIKELY POPS WITH THAT...LINGERING INTO
FRIDAY NIGHT WITH COLD FRONT IN THE VICINITY. EXPECT THERE TO BE
BREAKS BETWEEN THE ROUNDS OF LIKELY POPS...BUT WITH UNCERTAINTY ON
TIMING...ONLY DROPPED INTO LOW CHANCE DURING THESE BREAKS. NAM SHOWS
THE COLD FRONT MOVING THROUGH FRIDAY NIGHT OR EARLY SATURDAY
MORNING...HOWEVER ECMWF AND GFS ARE SLOWER...AND REALLY DO NOT EVEN
SINK IT ALL THE WAY THROUGH CWA BEFORE STALLING. TEND TO BELIEVE IN
A SLOWER SOLUTION...SO WILL KEEP CHANCE POPS EVERYWHERE EXCEPT
EXTREME NORTHERN CWA ON SATURDAY. EXPECT LOTS OF CLOUD COVER
THROUGHOUT THE SHORT TERM...AND ONLY MINOR CHANGES MADE TO HIGH AND
LOW TEMPERATURES. MAIN CHANGE WAS TO INCREASE LOWS FRIDAY NIGHT WITH
SLOWER FRONT.
CAN NOT RULE OUT ISOLATED WATER CONCERNS ON THURSDAY WITH PWAT
VALUES OF 1.5 TO 1.75 INCHES. FORTUNATELY...THE GROUND IS FAIRLY DRY
RIGHT NOW SO WILL TAKE SOME TIME TO SATURATE...AND ANTICIPATE IF WE
SEE PROBLEMS ON THURSDAY IT WILL BE ON THE ISOLATED SIDE. CONCERNS
ABOUT WATER INCREASE FOR FRIDAY HOWEVER. AS THE SURFACE WAVE
APPROACHES FROM THE SOUTHWEST...GOOD MOISTURE INFLOW WILL SPIKE
PWATS INTO THE 2 TO 2.5 INCH RANGE BY FRIDAY AFTERNOON. ALSO...FLOW
IS MORE PARALLEL TO THE FRONT ON FRIDAY SO SOME TRAINING MAY OCCUR.
WILL CONTINUE MENTION IN HWO FOR THURSDAY THROUGH SATURDAY.
&&
.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
GENERALLY USED WPC THINKING FOR THIS PORTION OF THE FORECAST.
HOWEVER...HAVE MADE SOME CHANGES TO REFLECT DIFFERENCES IN LATEST
MODEL GUIDANCE.
WPC INDICATES A COLD FRONT SHOULD BE LOCATED JUST TO OUR NORTHWEST
EARLY IN THE PERIOD...SLOWLY SINKING SOUTH. SEVERAL MID-LEVEL
SHORTWAVES AND A WEAK AREA OF LOW PRESSURE WILL THEN PUSH EAST
MONDAY INTO TUESDAY.
LATEST GFS IS SLOWER WITH THE SOUTHEAST PROGRESS OF THE COLD
FRONT. WITH THIS IN MIND...HAVE HELD ONTO LOW POPS A LITTLE LONGER
FOR SATURDAY NIGHT INTO SUNDAY.
LOWERED HPC TEMP NUMBERS A FEW DEGREES AS THEY APPEAR TOO WARM FOR
THE EXPECTED CONDITIONS.
&&
.AVIATION /08Z WEDNESDAY THROUGH SUNDAY/...
STILL THINKING CLOUDS WILL INCREASE AT 2 TO 4 THSD FT...WITH
CEILINGS BECOMING MORE COMMON BETWEEN 09Z AND 12Z THIS MORNING.
00Z NAM SHOWS NICE 925 MB MOISTURE CONVERGENCE. 06Z VAD WINDS
SHOWING FASTER 925 MB FLOW AT ILN DOWN TO JKL COMPARED TO
RLX...BACKING THAT FORECAST. AS A RESULT...WILL HOLD OFF FORMING
THICKER FOG...BUT 3 TO 5 MILES IN LIGHT FOG LIKELY IN SPOTS 09Z TO
12Z. A FEW SPOTTY SHOWERS COULD EASILY WITH THIS LOW LEVEL FORCING
08Z TO 12Z.
THE QUESTIONS FOR TODAY...IS THE COVERAGE OF THE LOWER CUMULUS AND
THE TIMING THE ROUNDS OF CONVECTION. CONFIDENCE IS LOW ON TIMING
THE CONVECTION. CURRENTLY HAVE COVERAGE OF SHOWERS AND
THUNDERSTORMS INCREASING IN THE SOUTH AND TRI STATE AROUND HTS BY
18Z THEN MOVING EAST 18Z WEDNESDAY TO 00Z THURSDAY.
QUESTIONS AGAIN ARISE ON WHAT HAPPENS TO THE CEILINGS 00Z TO 06Z
THURSDAY AND THE COVERAGE OF THE CONVECTION...THINKING THE 2 TO 3
THSD FT AGL CLOUDS WILL BE SCATTERED TO BROKEN. STILL CHANCE POPS
THROUGHOUT THE NIGHT IN THE MUGGY ENVIRONMENT.
VSBY WISE...A LOT OF 6 MILES IN HAZE OUTSIDE OF CONVECTION DURING
THE DAYLIGHT HOURS...LOWERING TO 4 MILES IN LIGHT FOG 00Z TO 06Z
THURSDAY. VSBY AOB 3 MILES IN CONVECTION.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z THURSDAY...
FORECAST CONFIDENCE: LOW.
ALTERNATE SCENARIOS: SOME THICKER FOG COULD BRIEFLY FORM IN SPOTS IN
WEST VIRGINIA FOR PREDAWN AND DAWN IF CLOUDS ARE SLOWER IN BECOMING
A CEILING. TIMING AND COVERAGE OF CONVECTION COULD 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 WED 08/07/13
UTC 1HRLY 08 09 10 11 12 13 14 15 16 17 18 19
EDT 1HRLY 04 05 06 07 08 09 10 11 12 13 14 15
CRW CONSISTENCY H H H H H M M M M M M M
HTS CONSISTENCY H H H H H H M H M M M M
BKW CONSISTENCY M H H H M H H H H M M M
EKN CONSISTENCY M H L L L H M H M M M M
PKB CONSISTENCY H H H H M M M M M M M M
CKB CONSISTENCY H H H M M M M M M M M M
AFTER 06Z THURSDAY...
IFR POSSIBLE IN ROUNDS OF CONVECTION INTO SATURDAY NIGHT. IN HUMID AIR
IFR CEILINGS COULD EVEN DEVELOP OUTSIDE THE CONVECTION...ESPECIALLY
AT NIGHT AND INTO THE MORNING.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...KTB/MZ
NEAR TERM...MZ
SHORT TERM...MZ
LONG TERM...JSH
AVIATION...KTB
AREA FORECAST DISCUSSION
NWS TULSA OK
647 PM CDT THU AUG 8 2013
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
SHOWERS AND THUNDERSTORMS WILL AFFECT KFSM AND MAY AFFECT
KMLC/KFYV/KXNA THIS EVENING. ADDITIONAL SHOWERS AND THUNDERSTORMS
WILL AFFECT THE AREA LATER TONIGHT INTO FRIDAY MORNING AND
GENERALLY FOLLOWED THE LATEST RUNS OF THE HRRR FOR TIMING. VFR
CONDITIONS WILL PREVAIL OUTSIDE OF THUNDERSTORM AREAS.
&&
.PREV DISCUSSION... /ISSUED 318 PM CDT THU AUG 8 2013/
DISCUSSION...
THE POTENTIAL FOR ANOTHER ROUND OF SIGNIFICANT FLOODING EXISTS FOR
PARTS OF FAR NORTHEAST OKLAHOMA AND FAR NORTHWEST ARKANSAS TONIGHT
AND INTO TOMORROW MORNING.
A CONVECTIVE COMPLEX IS EXPECTED TO DEVELOP ONCE AGAIN THIS
EVENING ACROSS THE TEXAS AND OKLAHOMA PANHANDLES AND INTO
SOUTHERN KANSAS...PUSHING TO THE EAST AND NORTHEAST ALONG A
REMNANT CONVECTIVE BOUNDARY EXTENDING FROM WEST CENTRAL OKLAHOMA
NORTHEASTWARD INTO SOUTHEAST KANSAS AND SOUTHWEST MISSOURI. THERE
ARE SOME SIGNS IN THE SATELLITE DATA THAT THIS DEVELOPMENT IS
BEGINNING. THE LOCATION OF THIS BOUNDARY WILL BE CRITICAL TO PIN
POINTING THE RAINFALL BULLSEYE. CURRENT THINKING IS THAT THIS WILL
BE IN A SIMILAR LOCATION TO LAST NIGHTS...WITH THE NAM/GFS
SOLUTIONS LIKELY BEING TOO FAR SOUTH. THIS EXPECTED PLACEMENT PUTS
LIKELY 1 TO 2 INCH RAINFALL AMOUNTS /LOCALLY HIGHER/ OVER REGIONS
THAT SAW AS MUCH AS 6 TO 7 INCHES LAST NIGHT AND EARLY THIS
MORNING.
LIKE A VERY BROKEN RECORD...FRIDAY NIGHT/SATURDAY MORNING SHOULD
FEATURE ANOTHER OVERNIGHT STORM COMPLEX WITH SMALL THUNDERSTORM
CHANCES AND COOL TEMPERATURES REMAINING THROUGH MOST OF THE
WEEKEND.
WITH NORTHWEST FLOW DEVELOPING OVER THE REGION...THE OVERNIGHT
COMPLEX POTENTIAL WILL RESUME EARLY NEXT WEEK...WITH SOME HEAVY
RAIN POTENTIAL. TEMPERATURES THROUGH NEXT WEEK WILL REMAIN JUST
BELOW NORMAL IN MOST LOCALES.
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...FLASH FLOOD WATCH UNTIL 1 PM FRIDAY FOR OKZ054-OKZ055-OKZ056-
OKZ057-OKZ058-OKZ063.
AR...FLASH FLOOD WATCH UNTIL 1 PM FRIDAY FOR ARZ001-ARZ002.
&&
$$
AVIATION...05
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1005 PM CDT THU AUG 8 2013
.UPDATE...ACTIVITY OVER WEST TENNESSEE IS DIMINISHING RAPIDLY AS
OUR QUIET WEATHER CONTINUES THIS EVENING. SURFACE FRONT WILL
INCH CLOSER TO MIDDLE TENNESSEE OVERNIGHT. HRRR SHOWS VERY LITTLE
PRECIPITATION MOVING ACROSS MIDDLE TENNESSEE OVER THE NEXT SEVERAL
HOURS, ALTHOUGH THE LATEST NAM SHOWS AN AXIS OF 850 MB MOISTURE
AND POSITIVE OMEGA PUSHING THROUGH THE MID STATE AFTER 06Z. GIVEN
THAT THE ATMOSPHERE REMAINS VERY MOIST AND MODESTLY UNSTABLE, AND
THE NOCTURNAL STORMS THAT DEVELOPED LAST NIGHT, AM LOATHE TO LOWER
POP`S THIS TIME. SO WILL LEAVE THE CURRENT FORECAST ALONE.
&&
.PREV DISCUSSION... /ISSUED 636 PM CDT THU AUG 8 2013/
UPDATE...FOR 00Z AVIATION.
AVIATION...00Z TAF DISCUSSION.
TONIGHT COULD PROVE TO BE VERY INTERESTING. BIGGEST PROBLEM IS
THAT GUIDANCE IS NOT HANDLING ANY OF OUR CONVECTION VERY WELL.
WITH A WARM FRONT TO OUR NORTH AND WEST...AND BOUNTIFUL SHORTWAVES
IN A WESTERLY FLOW ALOFT...MORE RAINS COULD BE ON THE WAY TONIGHT.
HAVE ILLUSTRATED THE LOW CONFIDENCE WITH VCSH AND VCTS THROUGH
THIS TAF CYCLE...BUT I THINK WE CAN COUNT ON FLIGHT CATEGORIES
BEING REDUCED OVERNIGHT EITHER WAY. WILL MONITOR UPSTREAM ACTIVITY
THAT IS FIRING AT ISSUANCE AND HANDLE THIS WITH AMDS AS WE GO
THROUGH THE NIGHT. WINDS WILL BE LIGHT FOR THE MOST PART OUT OF
THE ESE...VEERING TO THE SOUTHWEST BY TOMORROW AFTERNOON.
UNGER
PREV DISCUSSION... /ISSUED 302 PM CDT THU AUG 8 2013/
DISCUSSION...
MESO CONVECTIVE VORTICITY CENTER HAS CONTINUED TO PRODUCE SCATTERED
TO NUMEROUS THUNDERSTORMS IN MIDDLE TENNESSEE OCCASIONALLY CLUSTERING
WITH A STORM TWO NEARING SEVERE AT TIMES. THE MAIN THREAT FROM
THESE STORMS THIS AFTERNOON WILL BE WET MICROBURSTS. THIS ACTIVITY
WILL TRANSLATE EASTWARD DURING THE AFTERNOON AND EVENING. LOCALLY
HEAVY DOWNPOURS CAN ALSO BE EXPECTED WHICH MAY BRIEFLY AGGRAVATE
AREAS THAT HAVE ALREADY RECEIVED HEAVY RAINFALL. DID NOT ISSUE A
FLASH FLOOD WATCH FOR TONIGHT SINCE THE HEAVIER RAINFALL WILL BE
SO LOCALIZED...PLUS THE PRECIPITATION EFFICIENCY DECREASES
TONIGHT. BELIEVE THE MID LEVEL DRIER AIR CURRENTLY OVER LOUISIANA
AND ARKANSAS WILL BE ADVECTED THIS WAY. STILL...WITH SURFACE
BOUNDARY TO OUR NORTHWEST AND TRANSIENT IMPULSES ALOFT WORKING
ACROSS OUR AREA EXPECT TO SEE CONVECTION IN THE OVERNIGHT WITH THE
HIGHER POPS ACROSS THE NORTH. SURFACE FRONT WILL REMAIN GENERALLY
ALONG THE OHIO RIVER DOWN INTO NORTHWEST ARKANSAS WELL INTO THE
WEEKEND WITH A SERIES OF IMPULSES PROPAGATING ALONG THE BOUNDARY.
THIS MEANS THE CHANCE FOR SHOWERS AND STORMS INTO THE WEEKEND. IN
FACT I HAVE POPS IN THE FORECAST THROUGH THE MIDDLE OF NEXT WEEK.
BY THE MIDDLE OF NEXT A FRONT FINALLY PUSHES THROUGH OUR AREA WITH
HIGH PRESSURE SETTLING IN OVER THE UPPER MID WEST.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
ROSE
AREA FORECAST DISCUSSION...UPDATED
NWS MORRISTOWN TN
1024 PM EDT THU AUG 8 2013
.DISCUSSION...
SHOWER ACTIVITY HAS ENDED ACROSS MOST OF THE AREA. THE NAM HAS DONE
A POOR JOB DEPICTING THE EVENING PRECIP...SO THE RUC IS PREFERED. THE
RUC SHOWS SOME PRECIP MOVING IN FROM THE WEST LATE TONIGHT...SO
WILL KEEP A CHANCE POP GOING THERE WITH A SLIGHT CHANCE ELSEWHERE.
LIKE LAST NIGHT...LOW STRATUS WILL DEVELOP AFTER MIDNIGHT...WITH
LIGHT FOG IN SOME AREAS. OBSERVED TEMPS ARE A BIT BELOW
FORECAST...BUT LOWS IN THE UPPER 60S TO LOWER 70S LOOK ON TRACK
BASED ON CURRENT DEWPOINT TEMPS.
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
DGS
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
312 PM CDT WED AUG 7 2013
.DISCUSSION...
THE OUTFLOW BOUNDARY GENERATED FROM THIS MORNINGS MCS CONTINUES TO
PUSH ACROSS NORTHERN MISSISSIPPI. SCATTERED SHOWERS AND THUNDERSTORMS
HAVE DEVELOPED ALONG AND IN ADVANCE OF THE BOUNDARY AND WILL
CONTINUE TO PUSH ACROSS THE REMAINDER OF NORTH MISSISSIPPI OVER
THE NEXT COUPLE OF HOURS. THESE STORMS COULD BE STRONG WITH GUSTY
WINDS AND HEAVY RAIN. THE BOUNDARY HAS LIMITED HIGH TEMPS ACROSS
THE DELTA THOUGH THE SOUTHERN MOST COUNTIES...FROM TALLAHATCHIE TO
MONROE...HAVE WARMED INTO THE MID 90S WITH HEAT INDEX VALUES
FLIRTING WITH 105 DEGREES. THE REMNANTS OF THE COLD POOL HAVE
RESULTED IN A RELATIVELY NICE DAY ACROSS MUCH OF EASTERN AR...THE
MO BOOTHEEL AND WEST TENNESSEE WHERE TEMPS AR MOSTLY IN THE 80S
TO AROUND 90. THE AIRMASS STILL QUITE STABLE AND PRECIP FREE.
TONIGHT...LOOKING AT A FAIRLY QUITE EVENING GIVEN THE WORKED OVER
AIRMASS IN PLACE. WENT WITH A 20 POP OVER MOST OF THE AREA AND A
30 POP OVER NE ARKANSAS WHERE THE HRRR IS HINTING AT SOME DEVELOPMENT
BEFORE MIDNIGHT. LOOKING AT ANOTHER POTENTIAL MCS SCENARIO LATER
TONIGHT AS THE LOW LEVEL JET REDEVELOPS OVER EASTERN OK AND
WESTERN AR AND IMPINGES UPON THE WEAK STATIONARY FRONT ACROSS THE
AREA. THIS FRONT HAS BEEN HAVING TROUBLE LIFTING NORTH OVER THE
LAST COUPLE OF DAYS THANKS TO THE RECENT MCS ACTIVITY AND ASSOCD
COLD POOLS. AN AREA OF SHOWERS AND THUNDERSTORMS SHOULD BLOSSOM
OVER SRN MISSOURI AFTER MIDNIGHT AND THEN HEAD ESE AND SKIRT THE
NORTHERN TIER OF THE MIDSOUTH BY MORNING. POPS WILL DECREASE
SHARPLY TOWARD SOUTHERN AREAS OF THE MIDSOUTH. ANOTHER MILD NIGHT
ON TAP WITH LOWS IN THE MID 70S.
THURSDAY...EXPECT THE MCS TO SKIRT THE NORTHERN TIER AND WEAKEN AS
IT SPREADS EAST. BEST CHANCE WILL BE ACROSS NORTHERN AND EASTERN
SECTION WITH LESSER CHANCES TOWARD THE SOUTHWEST. MEX GUIDANCE
CONTINUES TO BE VERY WARM AND WENT CLOSER TO THE COOLER MET
GUIDANCE. EXPECT THAT ANOTHER OUTFLOW BOUNDARY MAY PUSH SOUTH WHICH
WILL HELP KEEP A LID ON TEMPS. AREAS SOUTHWEST OF MEMPHIS ARE
LIKELY TO GET THE WARMEST AND COULD FLIRT WITH HEAT ADVISORY
CRITERIA.
THURSDAY NIGHT THROUGH FRIDAY NIGHT...PATTERN REMAINS SIMILAR
WITH A BROAD UPPER RIDGE ACROSS THE SOUTHERN U.S AND A WEAK
STATIONARY FRONT ACROSS SOUTHERN MISSOURI. EXPECT MCS DEVELOPMENT
ALONG THIS FRONT EACH NIGHT WITH THE BEST CHANCES OF PRECIP ALONG
THE NORTHERN TIER OF THE MIDSOUTH. CONTINUED TO PREFER THE COOLER
MET GUIDANCE THOUGH PARTS OF NORTH MISSISSIPPI AND EAST CENTRAL
ARKANSAS WILL FLIRT WITH HEAT ADVISORY CRITERIA ON FRIDAY.
SATURDAY THROUGH SUNDAY...CONFIDENCE STARTING TO WANE AT THIS
POINT. UPPER RIDGE REMAINS ACROSS THE SOUTHERN U.S. WHILE THE WEAK
BOUNDARY TRIES TO SLIP SOUTH INTO THE MIDSOUTH BUT REALLY DOES
NOT MOVE MUCH. CHANCES FOR SHOWERS AND THUNDERSTORMS EXPECTED ACROSS
THE REGION. MEX STILL TOO WARM.
MONDAY THROUGH WEDNESDAY...MEDIUM RANGE MODELS INDICATE THAT AN
UPPER TROF WILL DEVELOP OVER THE EASTERN U.S. EARLY NEXT WEEK. THE
GFS IS NOT AS DEEP WITH THE TROF WHICH REESTABLISHES NORTHWEST
FLOW ACROSS THE REGION AND KEEPS THE SURFACE BOUNDARY IN THE AREA
RESULTING IN A RENEWED MCS PATTERN. THE ECMWF HAS A DEEPER TROF
AND ACTUALLY PUSHES THE FRONT SOUTH...SHUTTING OFF PRECIP
CHANCES. FOR NOW JUST WENT WITH A COMPROMISE OF 20 POPS AND
SLIGHTLY COOLER THAN NORMAL TEMPS.
SJM
&&
.AVIATION...
18Z TAF CYCLE
SHOWERS AND THUNDERSTORMS HAVE DISSIPATED WITH THE REMNANTS OF A
MESOSCALE CONVECTIVE SYSTEM ACROSS THE REGION. HOWEVER...THE
SHOWER/THUNDERSTORM FOCUS FOR THIS AFTERNOON WILL BE ACROSS NORTH
MISSISSIPPI IN ASSOCIATION WITH AN OUTFLOW BOUNDARY JUST
SOUTH/EAST OF MEM AS OF 18Z. THUS...WILL CARRY MENTION OF VCTS AT
TUP THROUGH 07/20Z. OTHERWISE...MAINLY RAIN FREE CONDITIONS WILL
CONTINUE AT TAF SITES INTO TONIGHT. ANOTHER UPPER LEVEL SHORTWAVE
TROUGH MAY DEVELOP ACROSS PORTIONS OF SOUTHERN MISSOURI TONIGHT
AND SPREAD INTO THE AREA THURSDAY MORNING. CONFIDENCE IS LOWER
WITH OVERALL SHOWER/THUNDERSTORM COVERAGE/PROBABILITIES AND WILL
CARRY VCSH FOR THURSDAY MORNING FOR THE TIME BEING.
NORTHWEST/NORTH WINDS BETWEEN 4-7 KTS THIS AFTERNOON WILL BACK
SOUTH AND DECREASE TO 4 KTS OR LESS TONIGHT AND AVERAGE BETWEEN
4-6 KTS THURSDAY MORNING. PATCHY FOG AND MVFR CONDITIONS POSSIBLE
AT JBR/MKL/TUP LATE TONIGHT.
CJC
&&
.PRELIMINARY POINT TEMPS/POPS...
MEM 77 93 78 94 / 30 30 10 30
MKL 73 88 74 91 / 50 60 30 40
JBR 75 90 75 92 / 50 40 30 40
TUP 75 93 75 93 / 20 40 10 40
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1245 PM CDT WED AUG 7 2013
.UPDATE...
UPDATED TO ADD 18Z AVIATION DISCUSSION.
&&
.PREV DISCUSSION... /ISSUED 1009 AM CDT WED AUG 7 2013/
DISCUSSION...
THE MCS SKIRTING THE NORTHERN FRINGES OF THE MIDSOUTH HAS BEEN
WEAKENING OVER THE LAST COUPLE OF HOURS. THIS COMPLEX WILL SHIFT
ESE OVER THE NEXT FEW HOURS AND CONTINUE TO BREAK APART. SOME
GRAVITY WAVES THAT...EMANATED FROM THE MCS...ARE VISIBLE ON THE
KNQA 88D IMAGERY ACROSS CENTRAL CRITTENDEN AND NORTHERN SHELBY
COUNTIES. A MORE SIGNIFICANT BOUNDARY STRETCHES FROM EASTERN
LAUDERDALE COUNTY INTO NORTH CROSS COUNTY. THIS MARKS THE LEADING
EDGE OF THE COLD POOL. THIS BOUNDARY...COMBINED WITH CLOUD
COVER...SHOULD LIMIT THE POTENTIAL HIGH TEMPS TODAY ACROSS MUCH OF
THE MIDSOUTH. CURRENT FORECAST IS FAIRLY CONSERVATIVE WITH TEMPS
AND THEY LOOK GOOD ATTM. HRRR DOES A GOOD JOB DEPICTING THIS
SOUTHWARD MOVING OUTFLOW BOUNDARY AND SHOWS SHOWERS AND
THUNDERSTORMS DEVELOPING ALONG IT AS IN MOVES THROUGH AN INCREASINGLY
UNSTABLE AIRMASS ACROSS NORTH MISSISSIPPI EARLY THIS
AFTERNOON.
INCREASED POPS ALONG THE NORTHERN TIER FOR THE REMAINDER OF THE
MORNING DUE TO ONGOING MCS. DECREASED POPS ALONG THE NORTHERN TIER
THIS AFTERNOON IN ANTICIPATION THAT THE MCS MOVES OFF TO THE
ESE. ADDED POPS TO THE SOUTHWEST PART OF THE CWA...DELTA
REGION...DUE TO THE OUTFLOW BOUNDARY MOVING THROUGH. UPDATE OUT.
SJM
PREV DISCUSSION... /ISSUED 236 AM CDT WED AUG 7 2013/
ANOTHER DAY AND ANOTHER MCS TO AFFECT THE MIDSOUTH TODAY. LATEST
RADAR IMAGES ARE LOOKING VERY REMINISCENT FROM LAST NIGHT. A LARGE
MCS IS CURRENTLY LOCATED OVER SOUTHEAST KANSAS AND NORTHEAST
OKLAHOMA AT THIS TIME. THE ONLY DIFFERENCE MAY BE IS THAT THE MCS
IS A LITTLE SLOWER SINCE BY THIS TIME LAST NIGHT THE MCS HAD
CROSSED INTO SOUTHWEST MISSOURI AND THE SOUTHERN EXTENT IS FURTHER
SOUTH THAN LAST NIGHTS. ON ITS CURRENT TRACK EXPECT THE REMNANTS
TO MOVE INTO NORTHEAST ARKANSAS BY 8 AM THIS MORNING.
MEANWHILE...ADDITIONAL CONVECTION HAS FIRED UP ACROSS SOUTHEAST
MISSOURI. THIS IS PRETTY SIMILAR TO WHAT OCCURRED LAST NIGHT. THE
CONVECTION IS ON THE NOSE OF THE LOW LEVEL JET AND AHEAD OF AN
APPROACHING WARM FRONT THAT IS CURRENTLY LOCATED FROM NEAR
JONESBORO TO CORINTH. THE CONVECTION IS EXPECTED TO EXPAND AND
INCREASE IN COVERAGE OVER THE NEXT COUPLE OF HOURS. ALREADY SEEING
THE FIRST SHOWERS POP UP OBION AND LAKE COUNTIES. THE ATMOSPHERE
IS VERY MOIST WITH PW/S OBSERVED AT 2.11 INCHES OFF THE 00Z BNA
SOUNDING. ISOLATED LOCATIONS ACROSS THE AREA SUCH AS WEAKLEY
COUNTY HAVE ALREADY RECEIVED A LARGE AMOUNT OF RAINFALL. FLASH
FLOOD GUIDANCE FOR ONE HOUR IS AT 1.8 FOR WEAKLEY COUNTY SO FLASH
FLOODING WILL BE A THREAT AGAIN TODAY FROM ANY THUNDERSTORMS THAT
DEVELOP OVER THE AREA. EXPECT BY MIDDAY...CONVECTION WILL BE THE
GREATEST ACROSS WEST TENNESSEE NEAR THE TENNESSEE RIVER. CLOUDS
AND CONVECTION WILL KEEP TEMPERATURES DOWN ACROSS AT LEAST THE
NORTHEAST HALF OF THE CWA. EXPECT HIGHS IN THE LOWER TO MID 80S.
MEANWHILE...ACROSS THE SOUTHWEST HALF OF THE CWA TEMPERATURES
SHOULD GET UP INTO THE LOWER TO MID 90S UNLESS ABUNDANT CIRRUS
FROM MCS KEEPS CONDITIONS COOLER. DEPENDING ON
DEWPOINTS...PHILLIPS COUNTY ARKANSAS AND PORTIONS OF NORTHWEST
MISSISSIPPI MAY NEED TO BE MONITORED FOR A HEAT ADVISORY. NOT
CONFIDENT AT THIS POINT TO ISSUE ONE DUE TO THE AMOUNT OF CLOUD
COVER HEADING TOWARD THE MIDSOUTH AT THIS TIME.
MODELS SUGGEST THE FRONTAL BOUNDARY WILL BE LOCATED NEAR THE MO/AR
BORDER THIS EVENING. EXPECT THE BOUNDARY TO BE THE MAIN SOURCE OF
CONVECTION. CAN/T RULE OUT ANOTHER MCS DEVELOPING AS WELL THUS
WILL KEEP HIGHEST POPS ACROSS THE NORTHERN AREAS.
CONFIDENCE IN FORECAST DROPS OFF AFTER TONIGHT. MODELS SUGGEST
FRONT MAY LIFT NORTHWARD INTO MISSOURI THURSDAY NIGHT INTO FRIDAY
THUS ANY MCS WOULD STAY NORTH OF THE CWA THURSDAY NIGHT INTO
FRIDAY MORNING. WILL THIS HAPPEN...WHO KNOWS. HOWEVER...AT LEAST DIURNAL
CONVECTION SHOULD STILL BE POSSIBLE ON FRIDAY. THE COLD FRONT SHOULD
SAG SOUTH INTO THE CWA OVER THE WEEKEND AND BRING DECENT CHANCES
FOR SHOWERS AND THUNDERSTORMS. HAVE BUMPED UP POPS FOR SATURDAY AS
A RESULT. HOW FAR SOUTH THE FRONT GOES REMAINS A QUESTION THAT THE
00Z GFS AND 00Z ECMWF DIFFER ON REGARDING THEIR SOLUTIONS. AS A RESULT...HAVE
LEFT FORECAST AS IS FOR MONDAY AND TUESDAY.
KRM
&&
.AVIATION...
18Z TAF CYCLE
SHOWERS AND THUNDERSTORMS HAVE DISSIPATED WITH THE REMNANTS OF A
MESOSCALE CONVECTIVE SYSTEM ACROSS THE REGION. HOWEVER...THE
SHOWER/THUNDERSTORM FOCUS FOR THIS AFTERNOON WILL BE ACROSS NORTH
MISSISSIPPI IN ASSOCIATION WITH AN OUTFLOW BOUNDARY JUST
SOUTH/EAST OF MEM AS OF 18Z. THUS...WILL CARRY MENTION OF VCTS AT
TUP THROUGH 07/20Z. OTHERWISE...MAINLY RAIN FREE CONDITIONS WILL
CONTINUE AT TAF SITES INTO TONIGHT. ANOTHER UPPER LEVEL SHORTWAVE
TROUGH MAY DEVELOP ACROSS PORTIONS OF SOUTHERN MISSOURI TONIGHT
AND SPREAD INTO THE AREA THURSDAY MORNING. CONFIDENCE IS LOWER
WITH OVERALL SHOWER/THUNDERSTORM COVERAGE/PROBABILITIES AND WILL
CARRY VCSH FOR THURSDAY MORNING FOR THE TIME BEING.
NORTHWEST/NORTH WINDS BETWEEN 4-7 KTS THIS AFTERNOON WILL BACK
SOUTH AND DECREASE TO 4 KTS OR LESS TONIGHT AND AVERAGE BETWEEN
4-6 KTS THURSDAY MORNING. PATCHY FOG AND MVFR CONDITIONS POSSIBLE
AT JBR/MKL/TUP LATE TONIGHT.
CJC
&&
.PRELIMINARY POINT TEMPS/POPS...
MEM 92 77 93 78 / 20 30 20 10
MKL 86 73 88 74 / 60 50 50 20
JBR 88 75 90 75 / 50 30 30 20
TUP 93 74 92 74 / 40 20 40 10
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1009 AM CDT WED AUG 7 2013
.DISCUSSION...
THE MCS SKIRTING THE NORTHERN FRINGES OF THE MIDSOUTH HAS BEEN
WEAKENING OVER THE LAST COUPLE OF HOURS. THIS COMPLEX WILL SHIFT
ESE OVER THE NEXT FEW HOURS AND CONTINUE TO BREAK APART. SOME
GRAVITY WAVES THAT...EMANATED FROM THE MCS...ARE VISIBLE ON THE
KNQA 88D IMAGERY ACROSS CENTRAL CRITTENDEN AND NORTHERN SHELBY
COUNTIES. A MORE SIGNIFICANT BOUNDARY STRETCHES FROM EASTERN
LAUDERDALE COUNTY INTO NORTH CROSS COUNTY. THIS MARKS THE LEADING
EDGE OF THE COLD POOL. THIS BOUNDARY...COMBINED WITH CLOUD
COVER...SHOULD LIMIT THE POTENTIAL HIGH TEMPS TODAY ACROSS MUCH OF
THE MIDSOUTH. CURRENT FORECAST IS FAIRLY CONSERVATIVE WITH TEMPS
AND THEY LOOK GOOD ATTM. HRRR DOES A GOOD JOB DEPICTING THIS
SOUTHWARD MOVING OUTFLOW BOUNDARY AND SHOWS SHOWERS AND
THUNDERSTORMS DEVELOPING ALONG IT AS IN MOVES THROUGH AN INCREASINGLY
UNSTABLE AIRMASS ACROSS NORTH MISSISSIPPI EARLY THIS
AFTERNOON.
INCREASED POPS ALONG THE NORTHERN TIER FOR THE REMAINDER OF THE
MORNING DUE TO ONGOING MCS. DECREASED POPS ALONG THE NORTHERN TIER
THIS AFTERNOON IN ANTICIPATION THAT THE MCS MOVES OFF TO THE
ESE. ADDED POPS TO THE SOUTHWEST PART OF THE CWA...DELTA
REGION...DUE TO THE OUTFLOW BOUNDARY MOVING THROUGH. UPDATE OUT.
SJM
&&
PREV DISCUSSION... /ISSUED 236 AM CDT WED AUG 7 2013/
ANOTHER DAY AND ANOTHER MCS TO AFFECT THE MIDSOUTH TODAY. LATEST
RADAR IMAGES ARE LOOKING VERY REMINISCENT FROM LAST NIGHT. A LARGE
MCS IS CURRENTLY LOCATED OVER SOUTHEAST KANSAS AND NORTHEAST
OKLAHOMA AT THIS TIME. THE ONLY DIFFERENCE MAY BE IS THAT THE MCS
IS A LITTLE SLOWER SINCE BY THIS TIME LAST NIGHT THE MCS HAD
CROSSED INTO SOUTHWEST MISSOURI AND THE SOUTHERN EXTENT IS FURTHER
SOUTH THAN LAST NIGHTS. ON ITS CURRENT TRACK EXPECT THE REMNANTS
TO MOVE INTO NORTHEAST ARKANSAS BY 8 AM THIS MORNING.
MEANWHILE...ADDITIONAL CONVECTION HAS FIRED UP ACROSS SOUTHEAST
MISSOURI. THIS IS PRETTY SIMILAR TO WHAT OCCURRED LAST NIGHT. THE
CONVECTION IS ON THE NOSE OF THE LOW LEVEL JET AND AHEAD OF AN
APPROACHING WARM FRONT THAT IS CURRENTLY LOCATED FROM NEAR
JONESBORO TO CORINTH. THE CONVECTION IS EXPECTED TO EXPAND AND
INCREASE IN COVERAGE OVER THE NEXT COUPLE OF HOURS. ALREADY SEEING
THE FIRST SHOWERS POP UP OBION AND LAKE COUNTIES. THE ATMOSPHERE
IS VERY MOIST WITH PW/S OBSERVED AT 2.11 INCHES OFF THE 00Z BNA
SOUNDING. ISOLATED LOCATIONS ACROSS THE AREA SUCH AS WEAKLEY
COUNTY HAVE ALREADY RECEIVED A LARGE AMOUNT OF RAINFALL. FLASH
FLOOD GUIDANCE FOR ONE HOUR IS AT 1.8 FOR WEAKLEY COUNTY SO FLASH
FLOODING WILL BE A THREAT AGAIN TODAY FROM ANY THUNDERSTORMS THAT
DEVELOP OVER THE AREA. EXPECT BY MIDDAY...CONVECTION WILL BE THE
GREATEST ACROSS WEST TENNESSEE NEAR THE TENNESSEE RIVER. CLOUDS
AND CONVECTION WILL KEEP TEMPERATURES DOWN ACROSS AT LEAST THE
NORTHEAST HALF OF THE CWA. EXPECT HIGHS IN THE LOWER TO MID 80S.
MEANWHILE...ACROSS THE SOUTHWEST HALF OF THE CWA TEMPERATURES
SHOULD GET UP INTO THE LOWER TO MID 90S UNLESS ABUNDANT CIRRUS
FROM MCS KEEPS CONDITIONS COOLER. DEPENDING ON
DEWPOINTS...PHILLIPS COUNTY ARKANSAS AND PORTIONS OF NORTHWEST
MISSISSIPPI MAY NEED TO BE MONITORED FOR A HEAT ADVISORY. NOT
CONFIDENT AT THIS POINT TO ISSUE ONE DUE TO THE AMOUNT OF CLOUD
COVER HEADING TOWARD THE MIDSOUTH AT THIS TIME.
MODELS SUGGEST THE FRONTAL BOUNDARY WILL BE LOCATED NEAR THE MO/AR
BORDER THIS EVENING. EXPECT THE BOUNDARY TO BE THE MAIN SOURCE OF
CONVECTION. CAN/T RULE OUT ANOTHER MCS DEVELOPING AS WELL THUS
WILL KEEP HIGHEST POPS ACROSS THE NORTHERN AREAS.
CONFIDENCE IN FORECAST DROPS OFF AFTER TONIGHT. MODELS SUGGEST
FRONT MAY LIFT NORTHWARD INTO MISSOURI THURSDAY NIGHT INTO FRIDAY
THUS ANY MCS WOULD STAY NORTH OF THE CWA THURSDAY NIGHT INTO
FRIDAY MORNING. WILL THIS HAPPEN...WHO KNOWS. HOWEVER...AT LEAST DIURNAL
CONVECTION SHOULD STILL BE POSSIBLE ON FRIDAY. THE COLD FRONT SHOULD
SAG SOUTH INTO THE CWA OVER THE WEEKEND AND BRING DECENT CHANCES
FOR SHOWERS AND THUNDERSTORMS. HAVE BUMPED UP POPS FOR SATURDAY AS
A RESULT. HOW FAR SOUTH THE FRONT GOES REMAINS A QUESTION THAT THE
00Z GFS AND 00Z ECMWF DIFFER ON REGARDING THEIR SOLUTIONS. AS A RESULT...HAVE
LEFT FORECAST AS IS FOR MONDAY AND TUESDAY.
KRM
&&
.AVIATION...
ONCE AGAIN BASED THE TAFS ON PERSISTENCE AND RADAR TRENDS MORE
THAN ANYTHING ELSE. CONVECTION UPSTREAM ACROSS MISSOURI WILL
CONTINUE TO SINK SOUTH AND EAST. FEEL LIKELY MOST OF THE STORMS
WILL STAY NORTH OF MEM...AND MOST LIKELY JBR...MOST CERTAINLY TUP.
MKL WILL LIKELY SEE STORMS ARRIVE AROUND 14Z...WITH PREVAILING
STORMS POSSIBLE SOMETIME BETWEEN 16AND 17Z. WILL TEMPO 3SM TSRA AT
MKL...FOR PLANNING PURPOSES...BUT THE EXACT TIME MAY NEED TO BE
ADJUSTED...ESPECIALLY IF ADDITIONAL STORMS DEVELOP AHEAD OF THE
ONGOING CONVECTION. ONLY INCLUDED VCTS AT JBR AND MEM FOR
NOW...STARTING AT 16Z...AND VCSH BY 20Z. ONCE AGAIN...ADDITIONAL
DEVELOPMENT MAY REQUIRE AMENDMENTS. LIGHT SOUTHERLY WINDS WILL
PREVAIL AT ALL SITES...BUT COULD BECOME VARIABLE AND GUSTY IN
ASSOCIATION WITH STORMS. JBR MAY SEE A EASTERLY SHIFT IN WINDS
OVERNIGHT. FOG MAY DEVELOP AT MKL AFTER 06Z TONIGHT.
&&
.PRELIMINARY POINT TEMPS/POPS...
MEM 93 77 93 78 / 20 30 20 10
MKL 83 73 88 74 / 60 50 50 20
JBR 88 75 90 75 / 50 30 30 20
TUP 92 74 92 74 / 40 20 40 10
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1234 AM CDT WED AUG 7 2013
.AVIATION 06Z...
MAIN FRONTAL BOUNDARY IS STILL LOCATED OFF TO THE SOUTHWEST
TONIGHT...WITH CONVECTION GOING STRONG ALONG IT WELL TO OUR WEST IN
OK/KS. THIS CONVECTION SHOULD TRACK ESE ALONG THE BOUNDARY AS IT
PUSHES NORTH. SKIES WILL BE SLOW TO CLEAR FOR CSV...BUT BNA AND
ESPECIALLY CKV SHOULD GET OUT OF THE BKN-OVC SKIES AT SOME POINT.
WITH THE AMPLE LOW-LEVEL MOISTURE IN PLACE...MAY LOWER THE VSBYS IN
THE TAFS CURRENTLY FOR THESE TWO LOCATIONS. CSV WILL EXPERIENCE MORE
OF A LOWERED STRATUS CLOUD DECK THAN THE BR/FG POSSIBLE AT BNA/CSV.
MAY DROP CONDITIONS DOWN TO IFR AT TIMES BETWEEN 06-12Z EARLY WED
MORN.
MAY SEE A FEW RANDOM SHRA POP UP...ESPECIALLY AT CSV...BEFORE
STRONGER CONVECTION OVER THE PLAINS REACHES MIDDLE TN...SHOULD IT
HOLD TOGETHER. IF IT FALLS APART...REDEVELOPMENT WEDNESDAY AFTERNOON
IS LIKELY AND WILL HAVE TO INSERT TEMPOS IN OR PREVAILING GROUPS IN
THE MOMENT FOR WEDNESDAY AFTER 18Z. ANY SHRA/TSRA ON WED WILL BRING
BRIEF IFR VSBYS/CIGS AS WELL AS THE POTENTIAL FOR BRIEF WIND GUSTS
OVER 40 KTS. OTHERWISE PREVAILING WINDS THROUGHOUT THIS TAF PERIOD
SHOULD MAINLY BE LIGHT AND SOUTHEASTERLY.
&&
.PREV DISCUSSION... /ISSUED 1021 PM CDT TUE AUG 6 2013/
UPDATE...RADAR CURRENTLY SHOWING WIDELY SCATTERED LIGHT SHOWERS
ACROSS MIDDLE TENNESSEE, WITH VERY HUMID AIR MASS IN PLACE.
EVENING SOUNDING FROM OHX SHOWS PRECIPITABLE WATER OF 2.11 INCHES
AND A K-INDEX OF 33. LIFTED INDEX REMAINS -5.6, WITH CONVECTIVE
AVAILABLE POTENTIAL ENERGY OF 2,528 J/KG, SO THERE`S PLENTY OF
INSTABILITY AROUND, TOO. LATEST HRRR SHOWS SCATTERED ACTIVITY
CONTINUING THROUGH THE NIGHT ACROSS MIDDLE TENNESSEE, BUT NOTHING
TOO HEAVY. EARLIER DROPPED EVENING POP`S FROM LIKELY TO SCATTERED,
LEAVING OVERNIGHT POP`S ALONE. GOING TO GO AHEAD AND REDUCE
OVERNIGHT POP`S TO SCATTERED, TOO, AS THERE`S NOTHING TO SUGGEST
MUCH OF AN INCREASE IN ACTIVITY BETWEEN 06Z AND 12Z.
PREV DISCUSSION... /ISSUED 701 PM CDT TUE AUG 6 2013/
UPDATE...CUTTING EVENING POP`S BACK TO SCATTERED GIVEN THE LACK
OF COVERAGE NOW AND THE LACK OF CONVECTIVE DEVELOPMENT FORECAST BY
THE HRRR THROUGH 06Z. LEAVING OVERNIGHT POP`S UNCHANGED.
PREV DISCUSSION... /ISSUED 636 PM CDT TUE AUG 6 2013/
UPDATE...FOR 00Z TAFS.
AVIATION...
AN UPPER LEVEL DISTURBANCE OVER WESTERN KY IS TRACKING ESE ACROSS
THE REGION. THIS WILL CONTINUE A CHANCE FOR OFF AND ON SHRA/TSRA
MAINLY IN A PERFECT LINE WITH OUR TERMINALS...FROM CKV TO BNA TO
CSV...OVER THE NEXT FEW HOURS. ONCE THE DISTURBANCE MOVES
EAST...SKIES SHOULD GO FROM BKN-OVC TO MORE FEW-SCT. HOWEVER
TOWARDS DAWN...A WARM FRONTAL BOUNDARY SOUTHWEST OF THE REGION
WILL PUSH NNE. VSBYS AHEAD OF THIS FEATURE COULD DROP GIVEN THE
AMOUNT OF LOW-LEVEL MOISTURE AND THUS WE CONTINUE THE MVFR VSBYS
AROUND DAWN (IFR AT CSV WITH MVFR CIGS). CHANCES FOR SHRA/TSRA
TOMORROW MORNING COULD BE ELEVATED IF A CONVECTIVE COMPLEX CAN GET
GOING OUT OVER THE PLAINS AND TRACK SOUTHEAST ALONG THE WARM
FRONT...WHICH SHOULD AFFECT OUR TAF SITES SHOULD IT HOLD TOGETHER.
OTHERWISE...A SCATTERED SHRA/TSRA CHANCE WILL BE THE RULE FOR MUCH
OF WEDNESDAY. CAN HANDLE BETTER TIMING WITH TEMPOS/PREVAILING
GROUPS WITH LATER FORECASTS.
PREV DISCUSSION... /ISSUED 324 PM CDT TUE AUG 6 2013/
DISCUSSION...UNSETTLED AND SOMEWHAT UNUSUAL AUGUST WX WILL
CONTINUE INTO THIS FORECAST PERIOD WITH INTERMITTENT SHOWERS AND
THUNDERSTORMS. OUR MAIN CONCERN THROUGH THE NEXT COUPLE OF DAYS IS
LOCALLY HEAVY RAINFALL. SO FAR...OUR COVERAGE AREA HAS NOT
RECEIVED CONCENTRATED HEAVY RAINFALL AMOUNTS...SO WE DO NOT NEED
ANY FLASH FLOOD WATCHES AT THIS TIME.
VERY MOIST AIR HAS BEEN MOVING INTO MID TN...AND DEEP MOISTURE
WILL REMAIN IN PLACE THROUGH AT LEAST THE NEXT 48 HOURS. FORECAST
SOUNDINGS SHOW PRECIPITABLE WATER VALUES CLIMBING WELL OVER 2
INCHES AT TIMES. LIFT ACROSS A WARM FRONTAL ZONE WILL PERSIST
THROUGH TONIGHT INTO WEDNESDAY MORNING AS ANOTHER UPPER WAVE
APPROACHES FROM THE WEST. ADDITIONAL IMPULSES AND RESIDUAL
BOUNDARIES WILL BE THE MAIN FACTORS TOMORROW AFTERNOON THROUGH
THURSDAY. ALL OF THIS MEANS A GOOD CHANCE FOR MORE RAIN AND
THUNDERSTORMS. UNFORTUNATELY...THERE ARE MANY UNCERTAINTIES
REGARDING THE EXACT TIMING AND EVOLUTION OF THE SHOWERS AND
STORMS...SO ANYONE WITH OUTDOOR PLANS WILL NEED TO KEEP A CLOSE
WATCH ON RADAR LOOPS AND SHORT RANGE FORECAST UPDATES. IN
GENERAL...1 TO 2 INCHES OF RAIN CAN BE EXPECTED THROUGH THE NEXT
COUPLE OF DAYS...BUT THE STRONGER STORMS WILL EASILY PRODUCE
LOCALIZED HEAVIER AMOUNTS...WITH RAINFALL RATES WELL OVER AN INCH
PER HOUR POSSIBLE.
A FEW STRONG STORMS WITH GUSTY WINDS ARE POSSIBLE TONIGHT.
TOMORROW AFTERNOON AND THURSDAY AFTERNOON LOOK LIKE THE MOST
UNSTABLE TIMES...WHEN A FEW SEVERE STORMS COULD DEVELOP. THESE
WOULD PRODUCE LOCALIZED STRONG WIND GUSTS...HEAVY DOWNPOURS AND
FREQUENT LIGHTNING. WE DO NOT SEE ANY WIDESPREAD OR WELL ORGANIZED
SEVERE WX THREAT AT THIS TIME.
BY FRIDAY AND CONTINUING INTO SATURDAY...RISING HEIGHTS WILL
DEVELOP WITH A BERMUDA RIDGE BRIDGING ACROSS TO A SOUTHERN PLAINS
RIDGE. THIS PATTERN WILL BRING VERY WARM AND HUMID CONDITIONS WITH
SCATTERED DIURNALLY DRIVEN THUNDERSTORMS.
MODELS INDICATE A FRONT DROPPING TOWARD THE AREA SATURDAY NIGHT
INTO SUNDAY. SOME SLIGHTLY DRIER AIR MAY SEEP IN FROM THE
NORTH...BUT WITH THE FRONT STALLING OVER THE AREA...SCATTERED
SHOWERS AND THUNDERSTORMS WILL CONTINUE.
LOOKING AHEAD INTO NEXT WEEK...MORE OF THE SAME UNSETTLED SUMMER
PATTERN OF 2013...AS NORTHWEST FLOW ALOFT BRINGS PERIODIC
DISTURBANCES ACROSS THE REGION.
13
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AL
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1218 PM CDT WED AUG 7 2013
.AVIATION...
Scattered altocumulus has persisted over the eastern counties this
morning with otherwise clear skies across West Central Texas. We`ll
see a surface based cu field develop by 20z with isolated showers
and thunderstorms possible, mainly west of a KSOA to KBWD line. I
did include VCSH for KABI and KSJT for the afternoon hours but given
the spatial uncertainty, I left mention of thunder out of the
current forecast. Any storms that develop this afternoon are
expected to dissipate by 02z. Winds will veer to a west to southwest
direction at KSJT and KSOA this afternoon with predominantly south
winds elsewhere. Expect occasional gusts exceeding 15 kts but
sustained winds will remain less than 12 kts.
Johnson
&&
.PREV DISCUSSION... /ISSUED 913 AM CDT WED AUG 7 2013/
UPDATE...
Isolated convection is ongoing over West TX this morning but this
activity is expected to dissipate over the next 1-2 hours. Scattered
altocumulus castellanus (ACCAS) have developed over portions of West
Central TX, indicating some mid level instability. We`ll see
relatively quiet weather conditions through early afternoon with a
surface based cu field developing after noon. With temperatures
warming well above 100 degrees, we should not have any trouble
tapping into this instability. Low-level forcing will be tied to a
surface trough although convergence will not be all that strong.
On the water vapor loop, the primary feature of interest is the
compact upper cyclone found to our south near the Big Bend. This low
is favorably located to enhance upper-level divergence across West
Central TX today. This could yield slightly better convective
coverage than I`m currently anticipating. I did change the
thunderstorms in the forecast to areal qualifiers and made minor
changes in the dewpoint, wind and sky grids. The public and fire
weather forecast products have been updated.
Johnson
PREV DISCUSSION... /ISSUED 647 AM CDT WED AUG 7 2013/
DISCUSSION...
See 12Z aviation discussion below.
AVIATION...
VFR conditions will prevail across the terminals the next 24 hours.
Isolated to widely scattered thunderstorms may develop late this
afternoon and early evening across western portions of the Big
Country, Concho Valley and northern Edwards Plateau. However,
limited coverage will preclude mentioning in the TAFS at this
time.
PREV DISCUSSION... /ISSUED 448 AM CDT WED AUG 7 2013/
SHORT TERM...
The main concern today will be convective chances late this
afternoon and evening and heat advisory conditions across the Big
Country.
The upper level high will be positioned over eastern Texas today
with a surface trough situated over our western counties by late
afternoon. A cold front currently over southern Kansas is expected
to drop south into northwest Texas by afternoon and become
stationary through the evening hours. Compressional warming ahead
of the front along with 850 millibar temperatures between 28 and 30
degrees Celsius will result in very hot temperatures again today.
The hottest temperatures will occur across the northeastern half of
the Big Country where compressional warming effects will be
greatest. Afternoon highs across this area will top out between 103
and 106 degrees with corresponding heat indices between 104 and 107
degrees. Elsewhere, expected highs between 100 and 104 degrees with
slightly lower heat indices. Included Jones County to the latest
heat advisory which also covers Haskell, Throckmorton and
Shackelford counties until 8 pm this evening.
The aforementioned surface trough will be a focus for convective
development by late afternoon across western counties as the cap
weakens with intense heating. The NAM seems to have a better handle
on this scenario as does the HRRR with both showing development
along the trough axis by late afternoon. Went ahead and added slight
pops generally west of a Throckmorton, Eden to Sonora line through
early evening. While widespread severe weather is not expected,
inverted V profiles with large dewpoint depressions will be
favorable for a few microbursts with the stronger cells. Storms will
be diurnally driven and should dissipate by mid to late evening with
loss of heating. Low temperatures tonight will generally be in the
mid and upper 70s.
24
LONG TERM...
Above normal temperatures will continue for all of West Central
Texas through much of the extended forecast, although showers and
thunderstorms may provide brief relief from the heat. Another hot
day is forecast, although 850mb temperatures are slightly cooler
than what we are expecting this afternoon. Highs should range from
99 to 102 over the southern counties to 101 to 104 across much of
the Big Country. Isolated to scattered showers and thunderstorms are
expected to develop along a surface trough across our western
counties by late afternoon. I included a slight chance of showers
and thunderstorms across mainly the western half of the area...with
a chance across the extreme western Concho Valley and Big Country.
In the meantime...a weak cold front will approach the northern Big
Country during the late evening or early morning hours. Scattered
showers and thunderstorms will be possible with the boundary...and I
have kept a slight chance POPs going through the overnight hours for
much of the Big Country. I trended my dewpoint temperatures closer
to the more moist NAM through Friday.
Model differences arise in the placement of a cold front across the
region on Friday and Saturday. The NAM is the fastest with the
boundary, stalling it across the Concho Valley during the early
morning hours Friday, while the GFS and ECMWF are about 6 to 10
hours slower. Given the expected boundary across area and decent
moisture to work with...I believe showers and thunderstorms will
develop across parts of the Big Country, Heartland, and Concho
Valley during the late afternoon/evening hours. Timing of the front
will make a difference on both high temperatures and placement of
best POPS, and for now I have kept a slight chance across generally
the northern half of the region, and I tweaked highs down slightly.
Although I cannot rule out an isolated shower or thunderstorms
Saturday as the diffuse boundary remains in the area, confidence is
not high enough to include in the forecast at this time.
An inverted trough/low will move across South Texas Sunday into
Monday, then into northern Mexico. Although the best dynamics
associated with this feature will remain south of area area, it
should pull in better gulf moisture Sunday and Monday. I cannot rule
out diurnally driven isolated showers and thunderstorms during the
afternoon hours, across mainly the southeast counties, but for now I
have kept the forecast dry. High temperatures should be slightly
above seasonal normals, generally in the mid and upper 90s, with
lows in the 70s.
Daniels
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 103 78 100 77 97 / 20 20 20 20 20
SAN ANGELO 105 76 102 76 98 / 20 20 20 20 20
JUNCTION 103 76 101 73 100 / 10 10 5 5 10
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR THE FOLLOWING
ZONES: HASKELL...JONES...SHACKELFORD...THROCKMORTON.
&&
$$
25
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
913 AM CDT WED AUG 7 2013
.UPDATE...
Isolated convection is ongoing over West TX this morning but this
activity is expected to dissipate over the next 1-2 hours. Scattered
altocumulus castellanus (ACCAS) have developed over portions of West
Central TX...indicating some mid level instability. We`ll see
relatively quiet weather conditions through early afternoon with a
surface based cu field developing after noon. With temperatures
warming well above 100 degrees, we should not have any trouble
tapping into this instability. Low-level forcing will be tied to a
surface trough although convergence will not be all that strong.
On the water vapor loop, the primary feature of interest is the
compact upper cyclone found to our south near the Big Bend. This low
is favorably located to enhance upper-level divergence across West
Central TX today. This could yield slightly better convective
coverage than I`m currently anticipating. I did change the
thunderstorms in the forecast to areal qualifiers and made minor
changes in the dewpoint, wind and sky grids. The public and fire
weather forecast products have been updated.
Johnson
&&
.PREV DISCUSSION... /ISSUED 647 AM CDT WED AUG 7 2013/
DISCUSSION...
See 12Z aviation discussion below.
AVIATION...
VFR conditions will prevail across the terminals the next 24 hours.
Isolated to widely scattered thunderstorms may develop late this
afternoon and early evening across western portions of the Big
Country, Concho Valley and northern Edwards Plateau. However,
limited coverage will preclude mentioning in the TAFS at this
time.
PREV DISCUSSION... /ISSUED 448 AM CDT WED AUG 7 2013/
SHORT TERM...
The main concern today will be convective chances late this
afternoon and evening and heat advisory conditions across the Big
Country.
The upper level high will be positioned over eastern Texas today
with a surface trough situated over our western counties by late
afternoon. A cold front currently over southern Kansas is expected
to drop south into northwest Texas by afternoon and become
stationary through the evening hours. Compressional warming ahead
of the front along with 850 millibar temperatures between 28 and 30
degrees Celsius will result in very hot temperatures again today.
The hottest temperatures will occur across the northeastern half of
the Big Country where compressional warming effects will be
greatest. Afternoon highs across this area will top out between 103
and 106 degrees with corresponding heat indices between 104 and 107
degrees. Elsewhere, expected highs between 100 and 104 degrees with
slightly lower heat indices. Included Jones County to the latest
heat advisory which also covers Haskell, Throckmorton and
Shackelford counties until 8 pm this evening.
The aforementioned surface trough will be a focus for convective
development by late afternoon across western counties as the cap
weakens with intense heating. The NAM seems to have a better handle
on this scenario as does the HRRR with both showing development
along the trough axis by late afternoon. Went ahead and added slight
pops generally west of a Throckmorton, Eden to Sonora line through
early evening. While widespread severe weather is not expected,
inverted V profiles with large dewpoint depressions will be
favorable for a few microbursts with the stronger cells. Storms will
be diurnally driven and should dissipate by mid to late evening with
loss of heating. Low temperatures tonight will generally be in the
mid and upper 70s.
24
LONG TERM...
Above normal temperatures will continue for all of West Central
Texas through much of the extended forecast, although showers and
thunderstorms may provide brief relief from the heat. Another hot
day is forecast, although 850mb temperatures are slightly cooler
than what we are expecting this afternoon. Highs should range from
99 to 102 over the southern counties to 101 to 104 across much of
the Big Country. Isolated to scattered showers and thunderstorms are
expected to develop along a surface trough across our western
counties by late afternoon. I included a slight chance of showers
and thunderstorms across mainly the western half of the area...with
a chance across the extreme western Concho Valley and Big Country.
In the meantime...a weak cold front will approach the northern Big
Country during the late evening or early morning hours. Scattered
showers and thunderstorms will be possible with the boundary...and I
have kept a slight chance POPs going through the overnight hours for
much of the Big Country. I trended my dewpoint temperatures closer
to the more moist NAM through Friday.
Model differences arise in the placement of a cold front across the
region on Friday and Saturday. The NAM is the fastest with the
boundary, stalling it across the Concho Valley during the early
morning hours Friday, while the GFS and ECMWF are about 6 to 10
hours slower. Given the expected boundary across area and decent
moisture to work with...I believe showers and thunderstorms will
develop across parts of the Big Country, Heartland, and Concho
Valley during the late afternoon/evening hours. Timing of the front
will make a difference on both high temperatures and placement of
best POPS, and for now I have kept a slight chance across generally
the northern half of the region, and I tweaked highs down slightly.
Although I cannot rule out an isolated shower or thunderstorms
Saturday as the diffuse boundary remains in the area, confidence is
not high enough to include in the forecast at this time.
An inverted trough/low will move across South Texas Sunday into
Monday, then into northern Mexico. Although the best dynamics
associated with this feature will remain south of area area, it
should pull in better gulf moisture Sunday and Monday. I cannot rule
out diurnally driven isolated showers and thunderstorms during the
afternoon hours, across mainly the southeast counties, but for now I
have kept the forecast dry. High temperatures should be slightly
above seasonal normals, generally in the mid and upper 90s, with
lows in the 70s.
Daniels
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 103 78 100 77 97 / 20 20 20 20 20
SAN ANGELO 105 76 102 76 98 / 20 20 20 20 20
JUNCTION 103 76 101 73 100 / 10 10 5 5 10
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR THE FOLLOWING
ZONES: HASKELL...JONES...SHACKELFORD...THROCKMORTON.
&&
$$
25
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
647 AM CDT WED AUG 7 2013
.DISCUSSION...
See 12Z aviation discussion below.
&&
.AVIATION...
VFR conditions will prevail across the terminals the next 24 hours.
Isolated to widely scattered thunderstorms may develop late this
afternoon and early evening across western portions of the Big
Country, Concho Valley and northern Edwards Plateau. However,
limited coverage will preclude mentioning in the TAFS at this
time.
&&
.PREV DISCUSSION... /ISSUED 448 AM CDT WED AUG 7 2013/
.SHORT TERM...
The main concern today will be convective chances late this
afternoon and evening and heat advisory conditions across the Big
Country.
The upper level high will be positioned over eastern Texas today
with a surface trough situated over our western counties by late
afternoon. A cold front currently over southern Kansas is expected
to drop south into northwest Texas by afternoon and become
stationary through the evening hours. Compressional warming ahead
of the front along with 850 millibar temperatures between 28 and 30
degrees Celsius will result in very hot temperatures again today.
The hottest temperatures will occur across the northeastern half of
the Big Country where compressional warming effects will be
greatest. Afternoon highs across this area will top out between 103
and 106 degrees with corresponding heat indices between 104 and 107
degrees. Elsewhere, expected highs between 100 and 104 degrees with
slightly lower heat indices. Included Jones County to the latest
heat advisory which also covers Haskell, Throckmorton and
Shackelford counties until 8 pm this evening.
The aforementioned surface trough will be a focus for convective
development by late afternoon across western counties as the cap
weakens with intense heating. The NAM seems to have a better handle
on this scenario as does the HRRR with both showing development
along the trough axis by late afternoon. Went ahead and added slight
pops generally west of a Throckmorton, Eden to Sonora line through
early evening. While widespread severe weather is not expected,
inverted V profiles with large dewpoint depressions will be
favorable for a few microbursts with the stronger cells. Storms will
be diurnally driven and should dissipate by mid to late evening with
loss of heating. Low temperatures tonight will generally be in the
mid and upper 70s.
24
.LONG TERM...
Above normal temperatures will continue for all of West Central
Texas through much of the extended forecast, although showers and
thunderstorms may provide brief relief from the heat. Another hot
day is forecast, although 850mb temperatures are slightly cooler
than what we are expecting this afternoon. Highs should range from
99 to 102 over the southern counties to 101 to 104 across much of
the Big Country. Isolated to scattered showers and thunderstorms are
expected to develop along a surface trough across our western
counties by late afternoon. I included a slight chance of showers
and thunderstorms across mainly the western half of the area...with
a chance across the extreme western Concho Valley and Big Country.
In the meantime...a weak cold front will approach the northern Big
Country during the late evening or early morning hours. Scattered
showers and thunderstorms will be possible with the boundary...and I
have kept a slight chance POPs going through the overnight hours for
much of the Big Country. I trended my dewpoint temperatures closer
to the more moist NAM through Friday.
Model differences arise in the placement of a cold front across the
region on Friday and Saturday. The NAM is the fastest with the
boundary, stalling it across the Concho Valley during the early
morning hours Friday, while the GFS and ECMWF are about 6 to 10
hours slower. Given the expected boundary across area and decent
moisture to work with...I believe showers and thunderstorms will
develop across parts of the Big Country, Heartland, and Concho
Valley during the late afternoon/evening hours. Timing of the front
will make a difference on both high temperatures and placement of
best POPS, and for now I have kept a slight chance across generally
the northern half of the region, and I tweaked highs down slightly.
Although I cannot rule out an isolated shower or thunderstorms
Saturday as the diffuse boundary remains in the area, confidence is
not high enough to include in the forecast at this time.
An inverted trough/low will move across South Texas Sunday into
Monday, then into northern Mexico. Although the best dynamics
associated with this feature will remain south of area area, it
should pull in better gulf moisture Sunday and Monday. I cannot rule
out diurnally driven isolated showers and thunderstorms during the
afternoon hours, across mainly the southeast counties, but for now I
have kept the forecast dry. High temperatures should be slightly
above seasonal normals, generally in the mid and upper 90s, with
lows in the 70s.
Daniels
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 103 78 100 77 97 / 20 20 20 20 20
SAN ANGELO 105 76 102 76 98 / 20 20 20 20 20
JUNCTION 103 76 101 73 100 / 10 10 5 5 10
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR THE FOLLOWING
ZONES: HASKELL...JONES...SHACKELFORD...THROCKMORTON.
&&
$$
24
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
448 AM CDT WED AUG 7 2013
.SHORT TERM...
The main concern today will be convective chances late this
afternoon and evening and heat advisory conditions across the Big
Country.
The upper level high will be positioned over eastern Texas today
with a surface trough situated over our western counties by late
afternoon. A cold front currently over southern Kansas is expected
to drop south into northwest Texas by afternoon and become
stationary through the evening hours. Compressional warming ahead
of the front along with 850 millibar temperatures between 28 and 30
degrees Celsius will result in very hot temperatures again today.
The hottest temperatures will occur across the northeastern half of
the Big Country where compressional warming effects will be
greatest. Afternoon highs across this area will top out between 103
and 106 degrees with corresponding heat indices between 104 and 107
degrees. Elsewhere, expected highs between 100 and 104 degrees with
slightly lower heat indices. Included Jones County to the latest
heat advisory which also covers Haskell, Throckmorton and
Shackelford counties until 8 pm this evening.
The aforementioned surface trough will be a focus for convective
development by late afternoon across western counties as the cap
weakens with intense heating. The NAM seems to have a better handle
on this scenario as does the HRRR with both showing development
along the trough axis by late afternoon. Went ahead and added slight
pops generally west of a Throckmorton, Eden to Sonora line through
early evening. While widespread severe weather is not expected,
inverted V profiles with large dewpoint depressions will be
favorable for a few microbursts with the stronger cells. Storms will
be diurnally driven and should dissipate by mid to late evening with
loss of heating. Low temperatures tonight will generally be in the
mid and upper 70s.
24
.LONG TERM...
Above normal temperatures will continue for all of West Central
Texas through much of the extended forecast, although showers and
thunderstorms may provide brief relief from the heat. Another hot
day is forecast, although 850mb temperatures are slightly cooler
than what we are expecting this afternoon. Highs should range from
99 to 102 over the southern counties to 101 to 104 across much of
the Big Country. Isolated to scattered showers and thunderstorms are
expected to develop along a surface trough across our western
counties by late afternoon. I included a slight chance of showers
and thunderstorms across mainly the western half of the area...with
a chance across the extreme western Concho Valley and Big Country.
In the meantime...a weak cold front will approach the northern Big
Country during the late evening or early morning hours. Scattered
showers and thunderstorms will be possible with the boundary...and I
have kept a slight chance POPs going through the overnight hours for
much of the Big Country. I trended my dewpoint temperatures closer
to the more moist NAM through Friday.
Model differences arise in the placement of a cold front across the
region on Friday and Saturday. The NAM is the fastest with the
boundary, stalling it across the Concho Valley during the early
morning hours Friday, while the GFS and ECMWF are about 6 to 10
hours slower. Given the expected boundary across area and decent
moisture to work with...I believe showers and thunderstorms will
develop across parts of the Big Country, Heartland, and Concho
Valley during the late afternoon/evening hours. Timing of the front
will make a difference on both high temperatures and placement of
best POPS, and for now I have kept a slight chance across generally
the northern half of the region, and I tweaked highs down slightly.
Although I cannot rule out an isolated shower or thunderstorms
Saturday as the diffuse boundary remains in the area, confidence is
not high enough to include in the forecast at this time.
An inverted trough/low will move across South Texas Sunday into
Monday, then into northern Mexico. Although the best dynamics
associated with this feature will remain south of area area, it
should pull in better gulf moisture Sunday and Monday. I cannot rule
out diurnally driven isolated showers and thunderstorms during the
afternoon hours, across mainly the southeast counties, but for now I
have kept the forecast dry. High temperatures should be slightly
above seasonal normals, generally in the mid and upper 90s, with
lows in the 70s.
Daniels
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 103 78 100 77 97 / 20 20 20 20 20
SAN ANGELO 105 76 102 76 98 / 20 20 20 20 20
JUNCTION 103 76 101 73 100 / 10 10 5 5 10
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR THE FOLLOWING
ZONES: HASKELL...JONES...SHACKELFORD...THROCKMORTON.
&&
$$
24/Daniels
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 BLACKSBURG VA
925 PM EDT THU AUG 8 2013
.SYNOPSIS...
WEAK UPPER LEVEL DISTURBANCES WILL CONTINUE TO MOVE EAST ACROSS
THE REGION INTO FRIDAY AHEAD OF A SLOW MOVING COLD FRONT
APPROACHING FROM THE NORTHWEST. THIS FRONT MOVES INTO THE
MOUNTAINS BY SATURDAY...AND SHIFTS SLOWLY TO THE SOUTH OF THE
REGION AFTER THE WEEKEND.
&&
.NEAR TERM /THROUGH FRIDAY/...
AS OF 915 PM EDT THURSDAY...
OUTFLOW BOUNDARY FROM SCATTERED TO NUMEROUS CONVECTION OVER THE
MOUNTAINS EARLIER TONIGHT SUPPORTING EASTWARD PROPAGATION OF
RAPIDLY DIMINISHING AREA OF SHOWERS ACROSS THE PIEDMONT AS AREA
ENCOUNTERS ADVERSE CONDITIONS DUE TO WESTERLY DOWNSLOPING WINDS
ABOVE BOUNDARY LAYER AND ONSET OF NIGHTTIME COOLING WITH
NEGLIGIBLE FORCING ALOFT.
CURRENT FORECAST STILL LOOKS ON TRACK...MAINTAINING A THREAT FOR
SOME ADDITIONAL WIDELY SCATTERED SHOWERS/STORMS...MAINLY WEST OF
THE BLUE RIDGE...WHERE SOMEWHAT STEEPER UPSTREAM MID LEVEL LAPSE
RATES RESIDE...AND WHERE UPSLOPING ACROSS WESTERN FLANKS OF
APPALACHIANS MAY PRODUCE NEEDED LOW LEVEL LIFT TO LEVEL OF FREE
CONVECTION ABOVE BOUNDARY LAYER. DEW POINT TEMPERATURES IN THE
UPPER 60S TO LOWER 70S...AND AT LEAST A RESIDUAL SCATTERED TO
BROKEN MID LEVEL DECK OF CLOUDS SHOULD ENSURE A WARM MUGGY NIGHT
ACROSS THE ENTIRE BLACKSBURG FORECAST AREA...WITH PATCHY FOG STILL
EXPECTED TO DEVELOP IN THE MOUNTAIN VALLEYS AND LOW LYING AREAS OF
THE PIEDMONT THAT RECEIVED RAIN EARLIER TODAY.
HAVE MADE ADJUSTMENTS TO REFLECT HOURLY TRENDS OF TEMPERATURES
AND DEW POINTS...BUT LEFT REMAINDER OF GRIDDED FORECAST FOR THE
REST OF THE NIGHT LARGELY UNCHANGED.
AS OF 240 PM EDT THURSDAY...
MAIN CONCERN CONTINUES WITH HEAVY RAIN PRODUCERS GIVEN PWATS NEAR
2 INCHES. WILL AGAIN REFRAIN FROM HOISTING A FLASH FLOOD WATCH
OVER THE WEST SINCE HEAVY RAIN HAS BEEN RATHER ISOLATED AND KEEP
MENTION IN THE HWO FOR LOCALIZED FLOODING AT THIS POINT. LEFTOVER
BOUNDARIES AND EVEN HIGHER FLUX OF PWATS SUPPORT KEEPING SOME
CHANCE POPS GOING OVERNIGHT. TEMPS SIMILAR TO THE PAST FEW NIGHTS
WITH LOWS IN THE MUGGY 65-72 RANGE UNDER PATCHY FOG.
WEAK FRONT TO THE NW WILL AGAIN BE SLOW TO DROP SE INTO THE AREA
FRIDAY GIVEN PARALLEL UPPER FLOW AND WEAK IMPULSES ALONG THE
BOUNDARY. HOWEVER APPEARS THAT WEAK PRE-FRONTAL CONVERGENCE IN
ADVANCE OF THE FRONT IN COMBO WITH MORE HEATING THAN TODAY WILL
HELP FOCUS CONVECTION INITIALLY OVER THE NW AND THEN POINTS SE
DURING THE AFTERNOON WHERE CAPES SHOULD BE GREATER. AXIS OF HIGHER
PROGGED 85H THETA-E ALONG ALONG THE MOUNTAINS SHOULD ALSO ALLOW
FOR MORE ORGANIZED STORMS AS SUPPORTED BY STRONGER WINDS ALOFT
WHICH LOOK TO ALIGN STORMS IN MORE LINEAR BANDS IN THE AFTERNOON.
THEREFORE RUNNING POPS FROM CHANCE EARLY ON...THEN INCREASING TO
LIKELYS FROM NW TO SE FROM MIDDAY THRU LATE AFTERNOON WITH BEST
CHANCES PIEDMONT LATE. OTRW EXPECTING MORE BREAKS PER BETTER
MIXING FRIDAY AFTER EARLY FOG/STRATUS EXIT ALLOWING TEMPS TO WARM
MORE AND PERHAPS APPROACH 90 SE IF MORE SUN DOES DEVELOP. ELSW
WILL BLEND BETWEEN THE WARMER MAV AND WETTER/COOLER MET MOS
PUTTING MOST IN THE 80S FOR HIGHS OUTSIDE OF THE HIGHER
ELEVATIONS.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
AS OF 330 PM EDT THURSDAY...
WEAK FRONT WILL SINK ACROSS THE REGION THROUGH THE WEEKEND.
A VERY SOUPY AIRMASS IN PLACE WITH WEAK WAVES ALONG THE FRONT
WILL PRODUCE SHOWERS AND STORMS...SOME WITH HEAVY RAINFALL. WITH
WEAK FLOW...THERE`S THE POSSIBILITY FOR MERGING STORMS WHICH IF
THIS OCCURS...WOULD LEAD TO FLASH FLOODING. OVERCAST SKIES FOR
MUCH OF THE DAY AND NIGHT ALONG WITH VEERING SURFACE WINDS TOWARDS
MORE OF A DOWNSLOPE DIRECTION WILL BECOME LIMITING FACTORS
INCREASINGLY OVER THE NEXT FEW DAYS. ATTM...EXTREME SW VA...NW NC
AND SE WEST VA SHOULD SEE THE MOST RAIN AS THOSE AREAS ARE IMMUNE
TO MEAN WESTERLY FLOW. PWATS DO DECREASE INTO SUNDAY WITH PERHAPS
HEAVIER RAIN PUSHED TO THE VA/NC BORDER...HOWEVER A SLOWER
BOUNDARY COULD KEEP MORE NUMEROUS SHOWERS AND STORMS OVER THE NEW
RIVER VALLEY THAT DAY TOO.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 350 PM EDT THURSDAY...
A COLD FRONT ASSOCIATED WITH AN IMPRESSIVE CHUNK OF CHILLY AIR FOR
THIS TIME OF YEAR WILL ALLOW SHOWERS AND STORMS TO CROP UP AGAIN ON
TUESDAY. ONCE THIS BOUNDARY PASSES...H85 TEMPS MAY FALL AS COLD AS
+9C BY THE MIDDLE OF NEXT WEEK. THE CHILLY AIR ALOFT WILL PRODUCE
EXTENSIVE CLOUDS AND PROBABLY WIDELY SCATTERED SHOWERS. BY THE END
OF NEXT WEEK...THIS FRONT BEGINS TO JOG NORTH AGAIN AND WARMER AIR
RETURNS.
&&
.AVIATION /01Z FRIDAY THROUGH TUESDAY/...
AS OF 750 PM EDT THURSDAY...
SERIES OF SHORT WAVE TROFS CONTRIBUTING TOWARD SCATTERED
CONVECTIVE ACTIVITY THIS EVENING. LEADING EDGE OF FIRST LINE OF
SHOWERS/STORMS MOVING EAST FROM OFF THE FOOTHILLS OF THE
APPALACHIANS ALONG OUTFLOW BOUNDARY THAT WAS GENERATED WHEN STORMS
DEVELOPED OVER/MOVED INTO AREAS FURTHER WEST EARLIER IN THE DAY.
LOCAL HRRR AND WRF MODELS INDICATE THAT MOST IF NOT ALL OF THIS
ACTIVITY WILL DIMINISH TO LIGHT SHOWERS BEFORE GETTING MUCH
FURTHER EAST THAN KLYH-KDAN LINE...SO INCORPORATED VCTS IN BOTH
RESPECTIVE TERMINAL FORECASTS UNTIL 02Z/10 PM EDT...TO BE FOLLOWED
BY DISSIPATION WITH LOSS OF SUPPORT DUE TO LOSS OF INSOLATION AND
WESTERLY DOWNSLOPING WINDS ABOVE BOUNDARY LAYER.
ADDITIONAL UPSTREAM SHORT WAVE ACTIVITY AND UPSLOPING WINDS ABOVE
THE BOUNDARY LAYER WEST OF THE BLUE RIDGE MAY SUPPORT WIDELY
SCATTERED CONVECTION CONTINUING IN WESTERN AREAS A BIT LATER INTO
TONIGHT...AND HAVE MAINTAINED VCTS MENTION AT KBLF AND KLWB UNTIL
06-07Z/2-3 AM EDT ACCORDINGLY.
EXPECT TO SEE DEVELOPMENT OF LIGHT FOG DRIVING VISIBILITIES DOWN
INTO MVFR RANGE IN MOST AREAS EAST OF THE BLUE RIDGE LATER TONIGHT
AS SKIES PARTIALLY CLEAR OVER A MOIST GROUND WHERE RAIN FELL...BUT
WITH IFR TO LOCALLY LIFR CONDITIONS EXPECTED TO DEVELOP IN THE
MOUNTAIN VALLEYS AND ACROSS THE WEST FLANKS OF THE BLUE RIDGE
WHERE LOW LEVEL MOISTURE WILL BE LIFTED DUE TO LIGHT UPSLOPE
WINDS. HAVE REFLECTED THIS DOWNWARD TREND AT KBCB...KBLF...AND
KLWB.
FRONT REMAINS JUST TO THE NORTHWEST ON FRIDAY WITH PERHAPS A PRE-
FRONTAL BAND OF LIFT HELPING TO ENHANCE AFTERNOON/EVENING
CONVECTION. LOOKS TO BE MORE HEATING THAN SEEN THU SO EXPECTING
TSRA MAY ORGANIZE MORE ESPCLY WEST/NW...THEN SPILLING SE ACROSS
MANY OF THE SITES DURING THE AFTERNOON. COULD BE SOME EARLY
MOUNTAIN SHRA AS WELL BEFORE HEATING KICKS IN WITH A GRADUAL
IMPROVEMENT TO VFR BY MID/LATE MORNING AS FOG/STRATUS SLOWLY
DISSIPATES.
FRIDAY NIGHT-MONDAY A FRONTAL BOUNDARY WILL BE IN THE VICINITY TO
SEE MORE COVERAGE OF SHOWERS/STORMS AREA WIDE. THIS WILL KEEP
TERMINALS DEALING WITH DELAYS DUE TO STORMS...BUT OVER HALF THE
TIME...IT SHOULD BE VFR. DRIER AIR PUSHES INTO NORTH ON MONDAY
WITH SCATTERED CONVECTION STILL POSSIBLE ESPECIALLY IN THE SOUTH.
ANOTHER COLD FRONT DROPPING IN FROM THE NW MAY CAUSE ADDED
SHRA/TSRA TUESDAY WITH SUB-VFR CONDITIONS POSSIBLE AT TIMES.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...JH/WP
NEAR TERM...JH/WERT
SHORT TERM...KM
LONG TERM...KM
AVIATION...DS/JH/WERT/WP
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
752 PM EDT THU AUG 8 2013
.SYNOPSIS...
WEAK UPPER LEVEL DISTURBANCES WILL CONTINUE TO MOVE EAST ACROSS
THE REGION INTO FRIDAY AHEAD OF A SLOW MOVING COLD FRONT
APPROACHING FROM THE NORTHWEST. THIS FRONT MOVES INTO THE
MOUNTAINS BY SATURDAY...AND SHIFTS SLOWLY TO THE SOUTH OF THE
REGION AFTER THE WEEKEND.
&&
.NEAR TERM /THROUGH FRIDAY/...
AS OF 240 PM EDT THURSDAY...
CONVECTION REMAINS CLUSTERED ACROSS THE MOUNTAINS THIS AFTERNOON
IN ADVANCE OF A MID LEVEL WAVE THAT WILL CROSS THE REGION THIS
EVENING BEFORE EXITING OVERNIGHT. LATEST SPC ANALYSIS SHOWS
RATHER WEAK INSTABILITY IN PLACE WHICH HAS LIMITED DEEP
CONVECTION WHILE MAIN CONCERN CONTINUES WITH HEAVY RAIN PRODUCERS
GIVEN PWATS NEAR 2 INCHES. EXPECT COVERAGE MAY FILL IN SOME WITH
PERHAPS A MORE ORGANIZED BAND OF SHRA/TSRA HEADING OUT TO THE
BLUE RIDGE...AND POINTS EAST IN THE NEXT FEW HOURS BEFORE LOSS OF
HEATING AND EXITING UPPER SUPPORT CAUSE SHRA TO FADE. THUS WILL
AGAIN REFRAIN FROM HOISTING A FLASH FLOOD WATCH OVER THE WEST
SINCE HEAVY RAIN HAS BEEN RATHER ISOLATED AND KEEP MENTION IN THE
HWO FOR LOCALIZED FLOODING AT THIS POINT. LEFTOVER BOUNDARIES AND
EVEN HIGHER FLUX OF PWATS SUPPORT KEEPING SOME CHANCE POPS GOING
OVERNIGHT EXCEPT THE FAR SE WITH CAT/LIKELYS EARLY ON INCLUDING
HEAVY RAIN MENTION. TEMPS SIMILAR TO THE PAST FEW NIGHTS WITH LOWS
IN THE MUGGY 65-72 RANGE UNDER PATCHY FOG.
WEAK FRONT TO THE NW WILL AGAIN BE SLOW TO DROP SE INTO THE AREA
FRIDAY GIVEN PARALLEL UPPER FLOW AND WEAK IMPULSES ALONG THE
BOUNDARY. HOWEVER APPEARS THAT WEAK PRE-FRONTAL CONVERGENCE IN
ADVANCE OF THE FRONT IN COMBO WITH MORE HEATING THAN TODAY WILL
HELP FOCUS CONVECTION INITIALLY OVER THE NW AND THEN POINTS SE
DURING THE AFTERNOON WHERE CAPES SHOULD BE GREATER. AXIS OF HIGHER
PROGGED 85H THETA-E ALONG ALONG THE MOUNTAINS SHOULD ALSO ALLOW
FOR MORE ORGANIZED STORMS AS SUPPORTED BY STRONGER WINDS ALOFT
WHICH LOOK TO ALIGN STORMS IN MORE LINEAR BANDS IN THE AFTERNOON.
THEREFORE RUNNING POPS FROM CHANCE EARLY ON...THEN INCREASING TO
LIKELYS FROM NW TO SE FROM MIDDAY THRU LATE AFTERNOON WITH BEST
CHANCES PIEDMONT LATE. OTRW EXPECTING MORE BREAKS PER BETTER
MIXING FRIDAY AFTER EARLY FOG/STRATUS EXIT ALLOWING TEMPS TO WARM
MORE AND PERHAPS APPROACH 90 SE IF MORE SUN DOES DEVELOP. ELSW
WILL BLEND BETWEEN THE WARMER MAV AND WETTER/COOLER MET MOS
PUTTING MOST IN THE 80S FOR HIGHS OUTSIDE OF THE HIGHER
ELEVATIONS.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
AS OF 330 PM EDT THURSDAY...
WEAK FRONT WILL SINK ACROSS THE REGION THROUGH THE WEEKEND.
A VERY SOUPY AIRMASS IN PLACE WITH WEAK WAVES ALONG THE FRONT
WILL PRODUCE SHOWERS AND STORMS...SOME WITH HEAVY RAINFALL. WITH
WEAK FLOW...THERE`S THE POSSIBILITY FOR MERGING STORMS WHICH IF
THIS OCCURS...WOULD LEAD TO FLASH FLOODING. OVERCAST SKIES FOR
MUCH OF THE DAY AND NIGHT ALONG WITH VEERING SURFACE WINDS TOWARDS
MORE OF A DOWNSLOPE DIRECTION WILL BECOME LIMITING FACTORS
INCREASINGLY OVER THE NEXT FEW DAYS. ATTM...EXTREME SW VA...NW NC
AND SE WEST VA SHOULD SEE THE MOST RAIN AS THOSE AREAS ARE IMMUNE
TO MEAN WESTERLY FLOW. PWATS DO DECREASE INTO SUNDAY WITH PERHAPS
HEAVIER RAIN PUSHED TO THE VA/NC BORDER...HOWEVER A SLOWER
BOUNDARY COULD KEEP MORE NUMEROUS SHOWERS AND STORMS OVER THE NEW
RIVER VALLEY THAT DAY TOO.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 350 PM EDT THURSDAY...
A COLD FRONT ASSOCIATED WITH AN IMPRESSIVE CHUNK OF CHILLY AIR FOR
THIS TIME OF YEAR WILL ALLOW SHOWERS AND STORMS TO CROP UP AGAIN ON
TUESDAY. ONCE THIS BOUNDARY PASSES...H85 TEMPS MAY FALL AS COLD AS
+9C BY THE MIDDLE OF NEXT WEEK. THE CHILLY AIR ALOFT WILL PRODUCE
EXTENSIVE CLOUDS AND PROBABLY WIDELY SCATTERED SHOWERS. BY THE END
OF NEXT WEEK...THIS FRONT BEGINS TO JOG NORTH AGAIN AND WARMER AIR
RETURNS.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
AS OF 750 PM EDT THURSDAY...
SERIES OF SHORT WAVE TROFS CONTRIBUTING TOWARD SCATTERED
CONVECTIVE ACTIVITY THIS EVENING. LEADING EDGE OF FIRST LINE OF
SHOWERS/STORMS MOVING EAST FROM OFF THE FOOTHILLS OF THE
APPALACHIANS ALONG OUTFLOW BOUNDARY THAT WAS GENERATED WHEN STORMS
DEVELOPED OVER/MOVED INTO AREAS FURTHER WEST EARLIER IN THE DAY.
LOCAL HRRR AND WRF MODELS INDICATE THAT MOST IF NOT ALL OF THIS
ACTIVITY WILL DIMINISH TO LIGHT SHOWERS BEFORE GETTING MUCH
FURTHER EAST THAN KLYH-KDAN LINE...SO INCORPORATED VCTS IN BOTH
RESPECTIVE TERMINAL FORECASTS UNTIL 02Z/10 PM EDT...TO BE FOLLOWED
BY DISSIPATION WITH LOSS OF SUPPORT DUE TO LOSS OF INSOLATION AND
WESTERLY DOWNSLOPING WINDS ABOVE BOUNDARY LAYER.
ADDITIONAL UPSTREAM SHORT WAVE ACTIVITY AND UPSLOPING WINDS ABOVE
THE BOUNDARY LAYER WEST OF THE BLUE RIDGE MAY SUPPORT WIDELY
SCATTERED CONVECTION CONTINUING IN WESTERN AREAS A BIT LATER INTO
TONIGHT...AND HAVE MAINTAINED VCTS MENTION AT KBLF AND KLWB UNTIL
06-07Z/2-3 AM EDT ACCORDINGLY.
EXPECT TO SEE DEVELOPMENT OF LIGHT FOG DRIVING VISIBILITIES DOWN
INTO MVFR RANGE IN MOST AREAS EAST OF THE BLUE RIDGE LATER TONIGHT
AS SKIES PARTIALLY CLEAR OVER A MOIST GROUND WHERE RAIN FELL...BUT
WITH IFR TO LOCALLY LIFR CONDITIONS EXPECTED TO DEVELOP IN THE
MOUNTAIN VALLEYS AND ACROSS THE WEST FLANKS OF THE BLUE RIDGE
WHERE LOW LEVEL MOISTURE WILL BE LIFTED DUE TO LIGHT UPSLOPE
WINDS. HAVE REFLECTED THIS DOWNWARD TREND AT KBCB...KBLF...AND
KLWB.
FRONT REMAINS JUST TO THE NORTHWEST ON FRIDAY WITH PERHAPS A PRE-
FRONTAL BAND OF LIFT HELPING TO ENHANCE AFTERNOON/EVENING
CONVECTION. LOOKS TO BE MORE HEATING THAN SEEN THU SO EXPECTING
TSRA MAY ORGANIZE MORE ESPCLY WEST/NW...THEN SPILLING SE ACROSS
MANY OF THE SITES DURING THE AFTERNOON. COULD BE SOME EARLY
MOUNTAIN SHRA AS WELL BEFORE HEATING KICKS IN WITH A GRADUAL
IMPROVEMENT TO VFR BY MID/LATE MORNING AS FOG/STRATUS SLOWLY
DISSIPATES.
FRIDAY NIGHT-MONDAY A FRONTAL BOUNDARY WILL BE IN THE VICINITY TO
SEE MORE COVERAGE OF SHOWERS/STORMS AREA WIDE. THIS WILL KEEP
TERMINALS DEALING WITH DELAYS DUE TO STORMS...BUT OVER HALF THE
TIME...IT SHOULD BE VFR. DRIER AIR PUSHES INTO NORTH ON MONDAY
WITH SCATTERED CONVECTION STILL POSSIBLE ESPECIALLY IN THE SOUTH.
ANOTHER COLD FRONT DROPPING IN FROM THE NW MAY CAUSE ADDED
SHRA/TSRA TUESDAY WITH SUB-VFR CONDITIONS POSSIBLE AT TIMES.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...JH/WP
NEAR TERM...JH
SHORT TERM...KM
LONG TERM...KM
AVIATION...DS/JH/WERT/WP
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
636 PM EDT WED AUG 7 2013
.SYNOPSIS...
HIGH PRESSURE REMAINS OFF THE COAST THROUGH THURSDAY. SOUTHERLY
RETURN FLOW AROUND THE HIGH WILL DRAW TROPICAL MOISTURE UP THE
EASTERN SEABOARD. A FRONT MOVES INTO THE MOUNTAINS BY THURSDAY
NIGHT INTO FRIDAY AND SLOWLY SHIFTS TO THE SOUTH OF US AFTER
THE WEEKEND.
&&
.NEAR TERM /THROUGH THURSDAY/...
AS OF 635 PM EDT WEDNESDAY...
NOT A LOT OF BIG CHANGES EARLY THIS EVENING. OUR FOCUS FOR THE
BEST COVERAGE OF SHOWERS AND STORMS HEADING INTO THE EVENING
REMAINS ACROSS THE MOUNTAINS...AND PERHAPS ONE OR TWO TIERS OF
COUNTIES EAST OF THE CREST OF THE BLUE RIDGE. LATEST LOCAL AND
REGIONAL RADAR TRENDS SHOW THE FORECAST DECREASE IN COVERAGE AND
INTENSITY. THIS TREND IS EXPECTED TO CONTINUE THROUGH THE EVENING.
HAVE TWEAKED TRENDS IN HOURLY TEMPERATURES AND DEW POINTS TO
REFLECT THE LATEST OBSERVATIONS AND EXPECTED TRENDS THROUGH THE
EVENING.
AS OF 340 PM EDT WEDNESDAY...
SCATTERED SHOWERS AND THUNDERSTORMS THIS AFTERNOON INTO THIS EVENING
WILL DIMINISH WITH THE LOSS OF SOLAR HEATING TONIGHT. CONTINUED THE
MENTION OF HEAVY RAIN WITH THUNDERSTORMS BECAUSE SOME OF THE
THUNDERSTORMS COULD BE EFFICIENT RAIN PRODUCERS. HOWEVER...NOT
EXPECTING WIDESPREAD FLASH FLOODING WITH 1 FFG RELATIVELY HIGH
RANGING FROM 1.6 TO 3 INCHES. LOCAL WATER PROBLEMS ARE POSSIBLE
DEPENDING ON EVOLUTION AND TRACK OF THUNDERSTORMS. PLACED THE
HIGHEST POPS IN THE WEST AND TAPER OFF AS ONE HEAD SOUTHEAST TONIGHT.
THERE IS THE POTENTIAL FOR SOME STORMS MOVE INTO THE WESTERN CWA
LATE TONIGHT INTO THURSDAY MORNING AS DEPICTED ON HRRR AND ECMWF.
WENT WITH WARMER MOS LOW TEMPERATURES FROM THE LOWER 60S IN THE
MOUNTAINS TO AROUND 70 DEGREES IN THE SOUTHEAST.
ISOLATED SHOWERS THURSDAY MORNING WILL BECOME SCATTERED SHOWERS AND
THUNDERSTORMS ACROSS THE MOUNTAINS THURSDAY AFTERNOON AND EVENING AS
WEAK DISTURBANCES PASS FROM WEST TO EAST IN THE ZONAL UPPER LEVEL
WIND FLOW. WITH PRECIPITABLE WATER FORECAST AROUND 2 INCHES AND SOME
CAPE...THERE COULD BE SOME THUNDERSTORMS WITH LOCALLY HEAVY RAINS.
A FEW OF THE STORMS COULD BE STRONG TO SEVERE ACROSS THE NORTH AS
SPC HAS A 5 PERCENT CHANCE FOR A SEVERE STORMS ON THURSDAY. PLAYED
HIGH TEMPERATURES ON THURSDAY FROM THE MID 70S IN THE MOUNTAINS TO
THE MID 80S IN THE PIEDMONTS.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
AS OF 400 PM EDT WEDNESDAY...
WITH A CLOSED LOW OVER THE UPPER GREAT LAKES AND A BROAD UPPER RIDGE
FROM THE WESTERN ATLANTIC THROUGH THE ARKLATEX...A STATIONARY
BOUNDARY WILL REMAIN NEAR OUR REGION THROUGH THE PERIOD. EVERY DAY
WILL FEATURE SHOWERS AND STORMS...WITH PERHAPS FRIDAY BEING THE
WETTEST DAY. THE BOUNDARY PERHAPS SINKS A LITTLE FURTHER SOUTH AND
WITH A WESTERLY/DOWNSLOPING WIND DEVELOPING...THERE MAY BE LESS
COVERAGE AND MORE FOCUS ACROSS SOUTHSIDE VIRGINIA AND THE NC
PIEDMONT. WITH LITTLE OR NO FLOW...BACKBUILDING AND/OR COLLIDING
STORMS...AND HIGH PWATS...THE OPPORTUNITY FOR FLASH FLOODING WILL
CONTINUE WITH A FLASH FLOOD WATCH PERHAPS NEEDED AT SOME POINT BASED
ON ANTECEDENT CONDITIONS.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 400 PM EDT WEDNESDAY...
WITH THE UPPER RIDGE CONSOLIDATING AND MOVING TO THE FOUR CORNERS
REGION...TROUGHING WILL DEEPEN AND STRENGTHEN ACROSS THE EAST AND
MIDDLE ATLANTIC. WITH THE COOLER TEMPS AND LESS MOISTURE...SHOWERS
AND STORMS WILL BECOME LESS LIKELY AND SUPPRESSED SOUTH AS THE WEEK
WEARS ON. HOWEVER...CAN`T TOTALLY RULE OUT A FEW POP UP SHOWERS
REGIONWIDE WITH SUCH CHILLY TEMPS ALOFT FOR THIS TIME OF YEAR.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
AS OF 130 PM EDT WEDNESDAY...
NUMEROUS MVFR SHOWERS AND THUNDERSTORMS EXPECTED IN THE WEST
WITH ISOLATED TO SCATTERED COVERAGE OF STORMS IN THE EAST.
PATCHES OF LOW CLOUDS IFR/LIFR WILL PERSIST ALONG THE SOUTHERN
BLUE RIDGE MOUNTAINS THIS AFTERNOON INTO TONIGHT.
LWB AND BLF TAF SITES HAVE THE BEST CHANCE FOR A THUNDERSTORM THIS
AFTERNOON INTO TONIGHT. HOWEVER...ANY TAF SITE COULD HAVE A
THUNDERSTORMS. AS IS THE CASE THIS TIME OF YEAR...THUNDERSTORMS IN
A HIGH MOIST AIRMASS WILL PUT HEAVY RAINS DOWN AND LOWER
CIGS/VSBYS.
TONIGHT...THE ACTIVTY WEAKENS BUT WILL LINGER INTO THE WV
MOUNTAINS AND KEPT VCTS TO VCSH THERE...WHILE CLOUDS SHOULD KEEP
FOG FROM BECOMING TO THICK...BUT CONFIDENCE IS HIGH THAT MVFR/IFR
VSBYS ARE POSSIBLE.
FOR THURSDAY...THE FOCUS REMAINS ALONG AND WEST OF THE BLUE RIDGE
WITH STORMS...AND BY FRIDAY-SUNDAY THE FRONTAL BOUNDARY WILL BE IN
THE VICINITY TO SEE MORE COVERAGE AREA WIDE. THIS WILL KEEP
TERMINALS DEALING WITH DELAYS DUE TO STORMS...BUT OVER HALF THE
TIME...IT SHOULD BE VFR. DRIER AIR PUSHES INTO NORTH ON MONDAY
WITH SCATTERED CONVECTION STILL POSSIBLE ESPECIALLY IN THE SOUTH.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...WP
NEAR TERM...DS/KK
SHORT TERM...KM
LONG TERM...KM
AVIATION...WP
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
400 PM EDT WED AUG 7 2013
.SYNOPSIS...
HIGH PRESSURE REMAINS OFF THE COAST THROUGH THURSDAY. SOUTHERLY
RETURN FLOW AROUND THE HIGH WILL DRAW TROPICAL MOISTURE UP THE
EASTERN SEABOARD. A FRONT MOVES INTO THE MOUNTAINS BY THURSDAY
NIGHT INTO FRIDAY AND SLOWLY SHIFTS TO THE SOUTH OF US AFTER
THE WEEKEND.
&&
.NEAR TERM /THROUGH THURSDAY/...
AS OF 340 PM EDT WEDNESDAY...
SCATTERED SHOWERS AND THUNDERSTORMS THIS AFTERNOON INTO THIS EVENING
WILL DIMINISH WITH THE LOSS OF SOLAR HEATING TONIGHT. CONTINUED THE
MENTION OF HEAVY RAIN WITH THUNDERSTORMS BECAUSE SOME OF THE
THUNDERSTORMS COULD BE EFFICIENT RAIN PRODUCERS. HOWEVER...NOT
EXPECTING WIDESPREAD FLASH FLOODING WITH 1 FFG RELATIVELY HIGH
RANGING FROM 1.6 TO 3 INCHES. LOCAL WATER PROBLEMS ARE POSSIBLE
DEPENDING ON EVOLUTION AND TRACK OF THUNDERSTORMS. PLACED THE
HIGHEST POPS IN THE WEST AND TAPER OFF AS ONE HEAD SOUTHEAST TONIGHT.
THERE IS THE POTENTIAL FOR SOME STORMS MOVE INTO THE WESTERN CWA
LATE TONIGHT INTO THURSDAY MORNING AS DEPICTED ON HRRR AND ECMWF.
WENT WITH WARMER MOS LOW TEMPERATURES FROM THE LOWER 60S IN THE
MOUNTAINS TO AROUND 70 DEGREES IN THE SOUTHEAST.
ISOLATED SHOWERS THURSDAY MORNING WILL BECOME SCATTERED SHOWERS AND
THUNDERSTORMS ACROSS THE MOUNTAINS THURSDAY AFTERNOON AND EVENING AS
WEAK DISTURBANCES PASS FROM WEST TO EAST IN THE ZONAL UPPER LEVEL
WIND FLOW. WITH PRECIPITABLE WATER FORECAST AROUND 2 INCHES AND SOME
CAPE...THERE COULD BE SOME THUNDERSTORMS WITH LOCALLY HEAVY RAINS.
A FEW OF THE STORMS COULD BE STRONG TO SEVERE ACROSS THE NORTH AS
SPC HAS A 5 PERCENT CHANCE FOR A SEVERE STORMS ON THURSDAY. PLAYED
HIGH TEMPERATURES ON THURSDAY FROM THE MID 70S IN THE MOUNTAINS TO
THE MID 80S IN THE PIEDMONTS.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
AS OF 400 PM EDT WEDNESDAY...
WITH A CLOSED LOW OVER THE UPPER GREAT LAKES AND A BROAD UPPER RIDGE
FROM THE WESTERN ATLANTIC THROUGH THE ARKLATEX...A STATIONARY
BOUNDARY WILL REMAIN NEAR OUR REGION THROUGH THE PERIOD. EVERY DAY
WILL FEATURE SHOWERS AND STORMS...WITH PERHAPS FRIDAY BEING THE
WETTEST DAY. THE BOUNDARY PERHAPS SINKS A LITTLE FURTHER SOUTH AND
WITH A WESTERLY/DOWNSLOPING WIND DEVELOPING...THERE MAY BE LESS
COVERAGE AND MORE FOCUS ACROSS SOUTHSIDE VIRGINIA AND THE NC
PIEDMONT. WITH LITTLE OR NO FLOW...BACKBUILDING AND/OR COLLIDING
STORMS...AND HIGH PWATS...THE OPPORTUNITY FOR FLASH FLOODING WILL
CONTINUE WITH A FLASH FLOOD WATCH PERHAPS NEEDED AT SOME POINT BASED
ON ANTECEDENT CONDITIONS.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 400 PM EDT WEDNESDAY...
WITH THE UPPER RIDGE CONSOLIDATING AND MOVING TO THE FOUR CORNERS
REGION...TROUGHING WILL DEEPEN AND STRENGTHEN ACROSS THE EAST AND
MIDDLE ATLANTIC. WITH THE COOLER TEMPS AND LESS MOISTURE...SHOWERS
AND STORMS WILL BECOME LESS LIKELY AND SUPPRESSED SOUTH AS THE WEEK
WEARS ON. HOWEVER...CAN`T TOTALLY RULE OUT A FEW POP UP SHOWERS
REGIONWIDE WITH SUCH CHILLY TEMPS ALOFT FOR THIS TIME OF YEAR.
&&
.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
AS OF 130 PM EDT WEDNESDAY...
NUMEROUS MVFR SHOWERS AND THUNDERSTORMS EXPECTED IN THE WEST
WITH ISOLATED TO SCATTERED COVERAGE OF STORMS IN THE EAST.
PATCHES OF LOW CLOUDS IFR/LIFR WILL PERSIST ALONG THE SOUTHERN
BLUE RIDGE MOUNTAINS THIS AFTERNOON INTO TONIGHT.
LWB AND BLF TAF SITES HAVE THE BEST CHANCE FOR A THUNDERSTORM THIS
AFTERNOON INTO TONIGHT. HOWEVER...ANY TAF SITE COULD HAVE A
THUNDERSTORMS. AS IS THE CASE THIS TIME OF YEAR...THUNDERSTORMS IN
A HIGH MOIST AIRMASS WILL PUT HEAVY RAINS DOWN AND LOWER
CIGS/VSBYS.
TONIGHT...THE ACTIVTY WEAKENS BUT WILL LINGER INTO THE WV
MOUNTAINS AND KEPT VCTS TO VCSH THERE...WHILE CLOUDS SHOULD KEEP
FOG FROM BECOMING TO THICK...BUT CONFIDENCE IS HIGH THAT MVFR/IFR
VSBYS ARE POSSIBLE.
FOR THURSDAY...THE FOCUS REMAINS ALONG AND WEST OF THE BLUE RIDGE
WITH STORMS...AND BY FRIDAY-SUNDAY THE FRONTAL BOUNDARY WILL BE IN
THE VICINITY TO SEE MORE COVERAGE AREA WIDE. THIS WILL KEEP
TERMINALS DEALING WITH DELAYS DUE TO STORMS...BUT OVER HALF THE
TIME...IT SHOULD BE VFR. DRIER AIR PUSHES INTO NORTH ON MONDAY
WITH SCATTERED CONVECTION STILL POSSIBLE ESPECIALLY IN THE SOUTH.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...WP/KK
NEAR TERM...KK
SHORT TERM...KM
LONG TERM...KM
AVIATION...WP/KK
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
141 PM EDT WED AUG 7 2013
.SYNOPSIS...
HIGH PRESSURE REMAINS OFF THE COAST THROUGH THURSDAY. A FRONT
MOVES INTO THE MOUNTAINS BY THURSDAY NIGHT INTO FRIDAY AND SLOWLY
SHIFTS TO THE SOUTH OF US AFTER THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 120 PM EDT WEDNESDAY...
CONVECTION DEVELOPING THIS AFTERNOON IN THE MOIST UNSTABLE
AIR AS HIGHLIGHTED BY RNKWRFARW AND HRRR. THUNDERSTORMS FIRE UP
DURING NEXT COUPLE OF HOURS WHERE LOW LEVEL LAPSE RATE HIGHEST
ACROSS WEST VIRGINIA AS SEEN ON SPC MESOSCALE ANALYSIS. ISOLATED
STORMS ALSO FORMING IN THE PIEDMONT. HOWEVER...THE BEST COVERAGE
SHOULD REMAIN IN THE WEST. MADE SOME MINOR ADJUSTMENTS IN ISC
GRIDS.
AS OF 950 AM EDT WEDNESDAY...
THIS MORNING 8AM/12Z RNK SOUNDING SHOWED THAT A WEST FLOW
CONTINUES ABOVE LOW LEVEL SOUTHERLY FLOW AND PWATS HAVE CLIMB TO
1.31 INCHES. HRRR AND RNKWRF-ARW INDICATED THAT BEST COVERAGE OF
SHOWERS AND THUNDERSTORMS THIS AFTERNOON WILL BE ACROSS THE WEST
MOUNTAINS. CONTINUED THE MENTION OF HEAVY RAIN WITH AFTERNOON
THUNDERSTORMS BECAUSE SOME OF THE THUNDERSTORMS COULD BE EFFICIENT
RAIN PRODUCERS. MADE SOME ADJUSTMENTS IN POPS AND WEATHER.
INCREASED POPS ACROSS SOUTHWEST PORTIONS OF FORECAST AREA LATE
MORNING INTO THIS AFTERNOON. ADJUSTED TEMPERATURES AND DEW POINTS
ACCORDING TO LATEST OBS AND TRENDS. MORE CHANGES LATER THIS
MORNING.
AS OF 710 AM EDT WEDNESDAY...
JUST A SHOWER OR TWO OUT THERE THIS MORNING ACROSS THE MOUNTAINS
INTO THE ROANOKE VALLEY. ALSO DENSE FOG HAS BECOME AN ISSUE ACROSS
THE BLUE RIDGE ALONG THE I-77 CORRIDOR AND SHOULD BURN OFF BY 14Z.
LATEST MODELS ARE ADVERTISING SOME DIFFERENCES THIS MORNING. THE
06Z NAM/GFS 00Z ECMWF ARE SHOWING CONVECTION ACROSS E TN/NRN GA
BUT OVERDOING THE COVERAGE. THE ECWMF HOWEVER IS DOING A BETTER
JOB HANDLING THE MCS ACROSS MO INTO WRN KY. FOR THIS MORNING WILL
KEEP CHANCE POPS INTO THE WEST PER CONVECTION POPPING ACROSS ERN
KY ATTM...WITH LESS THREAT IN THE PIEDMONT. STILL LOOKS LIKE BEST
CONVERGENCE ACROSS THE NC MTNS INTO FAR SRN WV THIS AFTERNOON...SO
NO CHANGES TO POPS THERE WITH HIGH CHANCE TO LOW LIKELY.
PREVIOUS VALID DISCUSSION...
GIVEN HIGH PWATS ADDED HEAVY RAIN THREAT WITH THE THUNDERSTORMS.
CANNOT RULE OUT ISOLATED FLASH FLOODING OR SVR SO WILL MENTION
THAT IN THE HWO.
LIKE TUESDAY...SKY COVER WILL BE VARIABLE BUT THINK MORE CLOUDS THAN
SUN EXPECTED AND KEPT TEMPS CLOSE TO A MODEL/MOS BLEND FOR HIGHS
WITH MID TO UPPER 70S WEST TO LOWER TO MID 80S EAST.
TONIGHT...THERE IS A POTENTIAL FOR WHAT IS GOING ON IN KS/MO THIS
MORNING TO GET CAUGHT UP IN THE WESTERLIES AS FLOW FLATTENS...MOVING
TOWARD OUR MOUNTAINS OVERNIGHT. HOWEVER...MODELS ARE FAVORING
KEEPING THE AXIS OF BEST LIFT...LOW LVL FORCING ACROSS THE OHIO/TN
VALLEYS AND MAY SEE SOME STORMS MOVE INTO THE WESTERN CWA LATE. SO
FOR NOW WILL KEEP HIGH CHANCE IN THE FAR WEST TONIGHT WITH
DIMINISHING POPS IN THE EAST. WITH CONTINUED MORE CLOUDS AND HIGH
MOIST CONTENT LOW TEMPS WILL BE IN THE 60S.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/...
AS OF 400 AM EDT WEDNESDAY...
WILL START THURSDAY OFF WITH ONLY ISOLATED SHOWERS THAT WILL BECOME
WIDELY SCATTERED SHOWERS AND THUNDERSTORMS ACROSS THE MOUNTAINS
DURING THE AFTERNOON AND EVENING AS WEAK DISTURBANCES PASS FROM WEST
TO EAST IN THE ZONAL UPPER LEVEL WIND FLOW. WILL AGAIN SEE A THREAT
OF LOCALLY HEAVY RAIN AS WEAKER UPPER LEVEL WINDS ASSOCIATED WITH
THE BUILDING RIDGE TO OUR SOUTH RESULT IN SLOWER STORM MOVEMENT...
WHILE DEEP ATMOSPHERIC MOISTURE POOLS AHEAD OF A COLD FRONT SITUATED
NEAR THE OHIO RIVER.
SHOWERS AND THUNDERSTORMS WILL BE MORE WIDESPREAD ON FRIDAY AS A
SHORTWAVE ROTATING AROUND AN UPPER LOW NORTH OF THE GREAT LAKES WILL
BEGIN TO NUDGE THE COLD FRONT FURTHER SOUTH. STRONG MOISTURE
ADVECTION SOUTH OF THE FRONT WILL PUSH PRECIPITABLE WATER VALUES TO
2 INCHES OR MORE FOR MOST OF OUR AREA...AND AFTERNOON HEATING WILL
PUSH CAPES INTO THE 1000 TO 1500 J/KG RANGE. WIND SPEEDS ALOFT WILL
BE A LITTLE STRONGER...BUT BELIEVE THAT STORMS WHICH DEVELOP WITH
AFTERNOON HEATING WILL BECOME VERY EFFICIENT RAINFALL PRODUCERS...
ENHANCING THE FLASH FLOOD THREAT FOR OUR AREA. WOULD ALSO NOT BE
SURPRISED TO SEE A FEW STORMS BECOME SEVERE...ESPECIALLY ACROSS THE
PIEDMONTS...CAPABLE OF PRODUCING DAMAGING WINDS.
MODELS ARE IN GENERAL AGREEMENT IN THEIR LATEST RUNS THAT THE
SHORTWAVE TROUGH MOVING EAST ACROSS CANADA WILL ADVANCE THE COLD
FRONT INTO NORTHERN VIRGINIA AND CENTRAL WEST VIRGINIA BY SATURDAY
AFTERNOON. WILL GO WITH THE MODEL CONSENSUS ON FRONTAL PLACEMENT...
KEEPING IN MIND THAT DISTURBANCES IN THE ZONAL FLOW ALOFT MAY CAUSE
THE FRONT TO WAVER NORTH AND SOUTH AT TIMES. THAT STATED...TRULY
DRIER AIR IS EXPECTED TO REMAIN WELL TO THE NORTH THROUGH SATURDAY
NIGHT...AND WILL STILL EXPECT SCATTERED SHOWERS AND THUNDERSTORMS
SATURDAY AFTERNOON AND EVENING.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
AS OF 400 AM EDT WEDNESDAY...
LOOKING AT BETTER AGREEMENT IN THE LONG TERM MODELS FOR EARLY NEXT
WEEK...WITH BOTH THE GFS AND ECMWF SOLUTIONS PUSHING THE COLD FRONT
INTO THE CAROLINAS BY MONDAY MORNING. THE SOUTHWARD PUSH OF THE
FRONT WILL MEAN ONLY SLIGHT CHANCES FOR SHOWERS AND THUNDERSTORMS
MONDAY AND TUESDAY...MAINLY SOUTH OF THE INTERSTATE 81 CORRIDOR.
WILL BE KEEPING AN EYE ON ANOTHER WAVE ALOFT DROPPING OUT OF CANADA
AND LIFTING MOISTURE BACK NORTH BY MIDWEEK...WHICH MAY SIGNAL A
RETURN OF MORE WIDESPREAD CONVECTION.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 130 PM EDT WEDNESDAY...
NUMEROUS MVFR SHOWERS AND THUNDERSTORMS EXPECTED IN THE WEST
WITH ISOLATED TO SCATTERED COVERAGE OF STORMS IN THE EAST.
PATCHES OF LOW CLOUDS IFR/LIFR WILL PERSIST ALONG THE SOUTHERN
BLUE RIDGE MOUNTAINS THIS AFTERNOON INTO TONIGHT.
LWB AND BLF TAF SITES HAVE THE BEST CHANCE FOR A THUNDERSTORM THIS
AFTERNOON INTO TONIGHT. HOWEVER...ANY TAF SITE COULD HAVE A
THUNDERSTORMS. AS IS THE CASE THIS TIME OF YEAR...THUNDERSTORMS IN
A HIGH MOIST AIRMASS WILL PUT HEAVY RAINS DOWN AND LOWER
CIGS/VSBYS.
TONIGHT...THE ACTIVTY WEAKENS BUT WILL LINGER INTO THE WV
MOUNTAINS AND KEPT VCTS TO VCSH THERE...WHILE CLOUDS SHOULD KEEP
FOG FROM BECOMING TO THICK...BUT CONFIDENCE IS HIGH THAT MVFR/IFR
VSBYS ARE POSSIBLE.
FOR THURSDAY...THE FOCUS REMAINS ALONG AND WEST OF THE BLUE RIDGE
WITH STORMS...AND BY FRIDAY-SUNDAY THE FRONTAL BOUNDARY WILL BE IN
THE VICINITY TO SEE MORE COVERAGE AREA WIDE. THIS WILL KEEP
TERMINALS DEALING WITH DELAYS DUE TO STORMS...BUT OVER HALF THE
TIME...IT SHOULD BE VFR. DRIER AIR PUSHES INTO NORTH ON MONDAY
WITH SCATTERED CONVECTION STILL POSSIBLE ESPECIALLY IN THE SOUTH.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...WP
NEAR TERM...KK/WP
SHORT TERM...NF
LONG TERM...JH
AVIATION...WP/KK
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
956 AM EDT WED AUG 7 2013
.SYNOPSIS...
HIGH PRESSURE REMAINS OFF THE COAST THROUGH THURSDAY. A FRONT
MOVES INTO THE MOUNTAINS BY THURSDAY NIGHT INTO FRIDAY AND SLOWLY
SHIFTS TO THE SOUTH OF US AFTER THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 950 AM EDT WEDNESDAY...
THIS MORNING 8AM/12Z RNK SOUNDING SHOWED THAT A WEST FLOW
CONTINUES ABOVE LOW LEVEL SOUTHERLY FLOW AND PWATS HAVE CLIMB TO
1.31 INCHES. HRRR AND RNKWRF-ARW INDICATED THAT BEST COVERAGE OF
SHOWERS AND THUNDERSTORMS THIS AFTERNOON WILL BE ACROSS THE WEST
MOUNTAINS. CONTINUED THE MENTION OF HEAVY RAIN WITH AFTERNOON
THUNDERSTORMS BECAUSE SOME OF THE THUNDERSTORMS COULD BE EFFICIENT
RAIN PRODUCERS. MADE SOME ADJUSTMENTS IN POPS AND WEATHER.
INCREASED POPS ACROSS SOUTHWEST PORTIONS OF FORECAST AREA LATE
MORNING INTO THIS AFTERNOON. ADJUSTED TEMPERATURES AND DEW POINTS
ACCORDING TO LATEST OBS AND TRENDS. MORE CHANGES LATER THIS
MORNING.
AS OF 710 AM EDT WEDNESDAY...
JUST A SHOWER OR TWO OUT THERE THIS MORNING ACROSS THE MOUNTAINS
INTO THE ROANOKE VALLEY. ALSO DENSE FOG HAS BECOME AN ISSUE ACROSS
THE BLUE RIDGE ALONG THE I-77 CORRIDOR AND SHOULD BURN OFF BY 14Z.
LATEST MODELS ARE ADVERTISING SOME DIFFERENCES THIS MORNING. THE
06Z NAM/GFS 00Z ECMWF ARE SHOWING CONVECTION ACROSS E TN/NRN GA
BUT OVERDOING THE COVERAGE. THE ECWMF HOWEVER IS DOING A BETTER
JOB HANDLING THE MCS ACROSS MO INTO WRN KY. FOR THIS MORNING WILL
KEEP CHANCE POPS INTO THE WEST PER CONVECTION POPPING ACROSS ERN
KY ATTM...WITH LESS THREAT IN THE PIEDMONT. STILL LOOKS LIKE BEST
CONVERGENCE ACROSS THE NC MTNS INTO FAR SRN WV THIS AFTERNOON...SO
NO CHANGES TO POPS THERE WITH HIGH CHANCE TO LOW LIKELY.
PREVIOUS VALID DISCUSSION...
GIVEN HIGH PWATS ADDED HEAVY RAIN THREAT WITH THE THUNDERSTORMS.
CANNOT RULE OUT ISOLATED FLASH FLOODING OR SVR SO WILL MENTION
THAT IN THE HWO.
LIKE TUESDAY...SKY COVER WILL BE VARIABLE BUT THINK MORE CLOUDS THAN
SUN EXPECTED AND KEPT TEMPS CLOSE TO A MODEL/MOS BLEND FOR HIGHS
WITH MID TO UPPER 70S WEST TO LOWER TO MID 80S EAST.
TONIGHT...THERE IS A POTENTIAL FOR WHAT IS GOING ON IN KS/MO THIS
MORNING TO GET CAUGHT UP IN THE WESTERLIES AS FLOW FLATTENS...MOVING
TOWARD OUR MOUNTAINS OVERNIGHT. HOWEVER...MODELS ARE FAVORING
KEEPING THE AXIS OF BEST LIFT...LOW LVL FORCING ACROSS THE OHIO/TN
VALLEYS AND MAY SEE SOME STORMS MOVE INTO THE WESTERN CWA LATE. SO
FOR NOW WILL KEEP HIGH CHANCE IN THE FAR WEST TONIGHT WITH
DIMINISHING POPS IN THE EAST. WITH CONTINUED MORE CLOUDS AND HIGH
MOIST CONTENT LOW TEMPS WILL BE IN THE 60S.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/...
AS OF 400 AM EDT WEDNESDAY...
WILL START THURSDAY OFF WITH ONLY ISOLATED SHOWERS THAT WILL BECOME
WIDELY SCATTERED SHOWERS AND THUNDERSTORMS ACROSS THE MOUNTAINS
DURING THE AFTERNOON AND EVENING AS WEAK DISTURBANCES PASS FROM WEST
TO EAST IN THE ZONAL UPPER LEVEL WIND FLOW. WILL AGAIN SEE A THREAT
OF LOCALLY HEAVY RAIN AS WEAKER UPPER LEVEL WINDS ASSOCIATED WITH
THE BUILDING RIDGE TO OUR SOUTH RESULT IN SLOWER STORM MOVEMENT...
WHILE DEEP ATMOSPHERIC MOISTURE POOLS AHEAD OF A COLD FRONT SITUATED
NEAR THE OHIO RIVER.
SHOWERS AND THUNDERSTORMS WILL BE MORE WIDESPREAD ON FRIDAY AS A
SHORTWAVE ROTATING AROUND AN UPPER LOW NORTH OF THE GREAT LAKES WILL
BEGIN TO NUDGE THE COLD FRONT FURTHER SOUTH. STRONG MOISTURE
ADVECTION SOUTH OF THE FRONT WILL PUSH PRECIPITABLE WATER VALUES TO
2 INCHES OR MORE FOR MOST OF OUR AREA...AND AFTERNOON HEATING WILL
PUSH CAPES INTO THE 1000 TO 1500 J/KG RANGE. WIND SPEEDS ALOFT WILL
BE A LITTLE STRONGER...BUT BELIEVE THAT STORMS WHICH DEVELOP WITH
AFTERNOON HEATING WILL BECOME VERY EFFICIENT RAINFALL PRODUCERS...
ENHANCING THE FLASH FLOOD THREAT FOR OUR AREA. WOULD ALSO NOT BE
SURPRISED TO SEE A FEW STORMS BECOME SEVERE...ESPECIALLY ACROSS THE
PIEDMONTS...CAPABLE OF PRODUCING DAMAGING WINDS.
MODELS ARE IN GENERAL AGREEMENT IN THEIR LATEST RUNS THAT THE
SHORTWAVE TROUGH MOVING EAST ACROSS CANADA WILL ADVANCE THE COLD
FRONT INTO NORTHERN VIRGINIA AND CENTRAL WEST VIRGINIA BY SATURDAY
AFTERNOON. WILL GO WITH THE MODEL CONSENSUS ON FRONTAL PLACEMENT...
KEEPING IN MIND THAT DISTURBANCES IN THE ZONAL FLOW ALOFT MAY CAUSE
THE FRONT TO WAVER NORTH AND SOUTH AT TIMES. THAT STATED...TRULY
DRIER AIR IS EXPECTED TO REMAIN WELL TO THE NORTH THROUGH SATURDAY
NIGHT...AND WILL STILL EXPECT SCATTERED SHOWERS AND THUNDERSTORMS
SATURDAY AFTERNOON AND EVENING.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
AS OF 400 AM EDT WEDNESDAY...
LOOKING AT BETTER AGREEMENT IN THE LONG TERM MODELS FOR EARLY NEXT
WEEK...WITH BOTH THE GFS AND ECMWF SOLUTIONS PUSHING THE COLD FRONT
INTO THE CAROLINAS BY MONDAY MORNING. THE SOUTHWARD PUSH OF THE
FRONT WILL MEAN ONLY SLIGHT CHANCES FOR SHOWERS AND THUNDERSTORMS
MONDAY AND TUESDAY...MAINLY SOUTH OF THE INTERSTATE 81 CORRIDOR.
WILL BE KEEPING AN EYE ON ANOTHER WAVE ALOFT DROPPING OUT OF CANADA
AND LIFTING MOISTURE BACK NORTH BY MIDWEEK...WHICH MAY SIGNAL A
RETURN OF MORE WIDESPREAD CONVECTION.
&&
.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
AS OF 730 AM EDT WEDNESDAY...
FOG AND MVFR CIGS WILL GIVE WAY TO VFR BY 15Z. SHOWERS AND STORMS
ENTER THE WESTERN CWA AFTER 16Z WITH ACTIVITY MORE SCATTERED EAST
OF ROANOKE THIS AFTERNOON. WILL STILL KEEP VCTS IN ALL TAFS AND
HAVE -SHRA IN THE PREDOMINANT WX. FOR NOW KEEPING VSBYS AOA 6SM
AND WILL HAVE TO AMEND IF STORMS HEAD TOWARD A TERMINAL.
CONFIDENCE IS HIGH THAT LWB/BLF WILL SEE RAIN. AS IS THE CASE THIS
TIME OF YEAR...STORMS IN A HIGH MOIST AIRMASS WILL PUT HEAVY RAINS
DOWN AND LOWER CIGS/VSBYS.
TONIGHT...THE ACTIVTY WEAKENS BUT WILL LINGER INTO THE WV
MOUNTAINS AND KEPT VCTS TO VCSH THERE...WHILE CLOUDS SHOULD KEEP
FOG FROM BECOMING TO THICK...BUT CONFIDENCE IS HIGH THAT MVFR/IFR
VSBYS ARE POSSIBLE.
FOR THURSDAY...THE FOCUS REMAINS ALONG AND WEST OF THE BLUE RIDGE
WITH STORMS...AND BY FRIDAY-SUNDAY THE FRONTAL BOUNDARY WILL BE IN
THE VICINITY TO SEE MORE COVERAGE AREA WIDE. THIS WILL KEEP
TERMINALS DEALING WITH DELAYS DUE TO STORMS...BUT OVER HALF THE
TIME...IT SHOULD BE VFR.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...WP
NEAR TERM...KK/WP
SHORT TERM...NF
LONG TERM...JH
AVIATION...WP
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
230 PM MDT WED AUG 7 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 300 PM MDT WED AUG 7 2013
SHOWERS AND THUNDERSTORMS WERE DEVELOPING EARLY THIS AFTERNOON
OVER VARIOUS PARTS OF THE CWA. THE ACTIVITY IS SLOWLY BECOMING
MORE INTENSE...BUT SO FAR HAS BEEN HINDERED SOME BY THE CIRRUS
CURRENTLY OVER THE AREA. AT LEAST A SCATTERED COVERAGE OF STORMS
SHOULD CONTINUE THROUGH EARLY THURSDAY MORNING. THE ATMOSPHERE
IS MOIST AND UNSTABLE WITH SURFACE FORCING NEAR THE MOUNTAINS.
IN ADDITION...A SHORTWAVE TROUGH NEAR THE FOUR CORNERS REGION
EARLY THIS AFTERNOON WILL MOVE NORTHEAST AND NEAR THE CWA
THROUGH EARLY THURSDAY MORNING. THE MAIN THREAT STILL APPEARS
TO BE A PERIOD OF HEAVY RAIN...SMALL HAIL AND GUSTY WINDS
THROUGH THE EVENING. THE BEST POTENTIAL FOR SEVERE STORMS WILL
BE IN THE NORTH PART OF THE CWA IN THE AREA OF BETTER 0-6 KM
SHEAR THROUGH THIS EVENING. AREAS OF LOW CLOUDS AND FOG WILL
BE POSSIBLE LATER TONIGHT AND INTO MID MORNING THURSDAY FROM
KSNY TO THE SOUTHERN LARAMIE RANGE.
BY MIDDAY THURSDAY...HEIGHTS ALOFT BUILD OVER THE ROCKIES WITH
A SHORTWAVE RIDGE OVER THE AREA THROUGH FRIDAY. THE PLUME OF
MID AND UPPER LEVEL MOISTURE WILL BE MAINLY OVER THE SOUTH PART
OF THE CWA THURSDAY AND THEN OVER THE ENTIRE CWA FRIDAY. MOIST
BOUNDARY LAYER UPSLOPE WINDS WILL CONTINUE THROUGH FRIDAY WITH
SURFACE DEW POINTS IN THE 50S TO THE EAST OF THE LARAMIE RANGE.
PRECIPITABLE WATER VALUES THROUGH THAT TIME WILL CONTINUE TO
RANGE FROM NEAR ONE HALF INCH OVER SOUTH CENTRAL WYOMING TO
AN INCH OVER THE PANHANDLE. A SCATTERED COVERAGE OF AFTERNOON
AND EVENING THUNDERSTORMS WILL AGAIN TAKE PLACE OVER THE CWA ON
THURSDAY. THEN ON FRIDAY...MODELS MOVE A MORE SIGNIFICANT
SHORTWAVE NEAR THE CWA. THAT SHOULD RESULT IN MORE COVERAGE AND
PERHAPS HEAVIER RAINFALL. TEMPERATURES WILL BE SIMILAR OVER
THE CWA THROUGH FRIDAY WITH READINGS NEAR OR JUST BELOW NORMAL.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 300 PM MDT WED AUG 7 2013
NEW ECMWF 12Z RUN CONTINUES TO BE MORE BULLISH ON QPF...PARTICULARLY
WEST OF THE LARAMIE RANGE FRIDAY NIGHT. NAM/WRF BACKS THE ECMWF
SOLUTIONS...SO KEPT PRETTY HIGH POPS GOING OUT WEST FRIDAY NIGHT.
THIS IS DUE TO A PRETTY POTENT VORT MAX TRACKING NORTHEAST THROUGH
THE RIDGE. ITS REALLY SLOW MOVING TO THE NORTHEAST AND BY SATURDAY
MORNING...IT FINALLY CLEARS TO CWFA. SO CURRENTLY THINKING IS FOR
SHOWERS AND THUNDERSTORMS TO CONTINUE ALL NIGHT...PARTICULARLY OUT
WEST AND INTO CONVERSE COUNTY.
RESIDUAL MOISTURE AND UPSLOPING WINDS EAST OF THE LARAMIE RANGE
WILL AID IN ANOTHER ROUND OF AFTERNOON AND EVENING SHOWERS AND
THUNDERSTORMS SATURDAY AND SATURDAY EVENING.
WE ARE LOOKING AT THE BROKEN RECORD CONTINUING THROUGH MID WEEK AS
MONSOONAL MOISTURE REMAINS OVER THE AREA. ITS A GOOD PROBLEM TO
HAVE AS WE ARE STILL WAY BELOW ON RAINFALL...AND THE RAIN KEEPS
FIRE WEATHER CONCERNS AT BAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY MORNING)
ISSUED AT 1046 AM MDT WED AUG 7 2013
LOOKS LIKE ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS FOR THIS
AFTERNOON. LATEST HRRR FORECAST SHOWING THUNDERSTORMS FORMING
ALONG A LINE JUST NORTH OF CHADRON OVER TO LUSK AROUND
19Z...SWEEPING SOUTH THROUGH THE SOUTHERN PANHANDLE BY
00Z. BASED TIMING ON ITS FORECAST. THEN BEHIND THE LINE...WE SEE A
NORTHEAST WIND DEVELOPING BEHIND THIS LINE. HRRR AND SREF SHOWING
A FAIRLY WIDESPREAD AND PROLONGED LOW CEILING EVENT WITH THESE
NORTHEAST UPSLOPING WINDS. BELIEVE THE MOST PROBABLE AREA WILL BE
HERE AT KCYS AND KSNY IN THE SOUTHERN PANHANDLE. BUT KAIA AND KBFF
COULD ALSO BE IMPACTED. SHOULD THESE AIRPORTS AND THE PANHANDLE
RECEIVE GOOD RAINFALL TODAY...THEN CONFIDENCE WILL CERTAINLY GROW
THAT IT WILL HAPPEN.
&&
.FIRE WEATHER...
ISSUED AT 300 PM MDT WED AUG 7 2013
MONSOONAL MOISTURE WILL REMAIN OVER THE CWA THROUGH AT LEAST
FRIDAY. THE RESULT WILL BE AT LEAST A SCATTERED COVERAGE OF
MAINLY LATE DAY SHOWERS AND THUNDERSTORMS EACH DAY AND
TEMPERATURES AT OR JUST BELOW NORMAL. THE ATMOSPHERE DRIES
SOME FOR THE WEEKEND AND EARLY NEXT WEEK AND MAY RESULT IN
MARGINAL FIRE WEATHER CONDITIONS FOR THE LOWER ELEVATIONS OF THE
WEST PART OF THE CWA. HOWEVER...WINDS IN MOST AREAS WILL BE
FAIRLY LIGHT THROUGH EARLY NEXT WEEK. IN GENERAL THAT LEADS TO
A REDUCED FIRE WEATHER CONCERN OVER THE CWA DURING THAT TIME.
DRY THUNDERSTORMS WILL BE A POSSIBILITY ON SOME DAYS OVER THE
LOWER ELEVATIONS OF CARBON COUNTY.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...WEILAND
LONG TERM...CLAYCOMB
AVIATION...CLAYCOMB
FIRE WEATHER...WEILAND
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1055 AM MDT WED AUG 7 2013
.UPDATE...
ISSUED AT 1023 AM MDT WED AUG 7 2013
THIS AFTERNOON AND EVENING SHOULD BE FAIRLY ACTIVE OVER MUCH OF
THE CWA. THE ATMOSPHERE WILL CONTINUE TO DESTABILIZE THROUGH THE
AFTERNOON AND PRECIPITABLE WATER VALUES WILL BE AROUND THREE
QUARTERS OF AN INCH. IN ADDITION...THE LOW LEVEL THETA-E RIDGE
AXIS WILL BE OVER THE EAST PART OF THE CWA. ALONG WITH SURFACE
FORCING...A SHORTWAVE TROUGH CURRENTLY TO OUR SOUTH WILL LIFT
NORTH AND AFFECT THE SOUTH THIRD OF THE CWA THIS AFTERNOON AND
EVENING. ANOTHER SHORTWAVE TROUGH WILL MOVE ACROSS THE NORTH
PART OF THE CWA DURING THAT TIME. STORMS IN THE SOUTH WILL LIKELY
PRODUCE A PERIOD OF HEAVY RAIN...GUSTY WINDS AND SMALL HAIL.
MEANWHILE...THOSE IN THE NORTH WILL HAVE BETTER SHEAR AND STRONGER
STORMS WILL BE POSSIBLE. THERE CONTINUES TO BE A POTENTIAL FOR
MORE LANDSPOUTS THIS AFTERNOON AND EVENING WITH THE STORMS. IN
A RECENT UPDATE...INCREASED POPS AND ADDED HEAVY RAIN...HAIL
AND WINDS WILL THE THUNDERSTORMS. ALSO MADE MINOR ADJUSTMENTS TO
THE REST OF THE FIRST PERIOD OF THE FORECAST.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY AFTERNOON)
ISSUED AT 439 AM MDT WED AUG 7 2013
A FEW ELEVATED WARM ADVECTION SHOWERS OVER THE NEBRASKA PANHANDLE
AS OF 10Z. THIS ACTIVITY SHOULD SHIFT EAST OF THE AREA THIS
MORNING WITH THE AREA OF STRONGER ISENTROPIC FORCING. HOWEVER...
BROAD WEAK FORCING WILL BE IN PLACE ACROSS THE EASTERN 1/2 OF THE
FORECAST AREA THROUGH THE REMAINDER OF THE MORNING SO CAN`T RULE
OUT ISOLATED THUNDERSTORMS AS THE ELEVATED INSTABILITY IS IN
PLACE.
ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS IS ON TAP FOR
LATE TODAY...BUT COVERAGE AND INTENSITY IS A BIG QUESTION GIVEN
THE VERY POOR PERFORMANCE OF SHORT TERM MODELS THE LAST SEVERAL
DAYS. SEVERE THREAT APPEARS MINIMAL BUT WILL HAVE TO KEEP A CLOSE
EYE ON STORMS THIS AFTERNOON. NAM AND GFS DIFFER SOMEWHAT ON THE
CAPE WITH THE NAM INDICATING HIGHER VALUES NEAR 2000 J/KG WHILE
THE GFS IS CLOSER TO 1000 J/KG. DEEP LAYER SHEAR NOT AS STRONG AS
MANY DAYS THE LAST FEW WEEKS...BUT THERE MAY BE ENOUGH CAPE AND
SHEAR FOR A FEW SUPERCELLS THIS AFTERNOON AND EARLY EVENING EAST
OF THE LARAMIE RANGE. IT DOES APPEAR THE MAIN POTENTIAL FOR
STRONGER STORMS WILL BE IN THE NORTH OVER CONVERSE AND NIOBRARA
COUNTY AND THE NORTHERN NEBRASKA PANHANDLE. OF COURSE THAT IS
BASED ON CURRENT NAM AND GFS PROJECTIONS WHICH HAVE BEEN SUSPECT
AT BEST THE LAST SEVERAL DAYS...SO CONFIDENCE IS LOW.
ONE CONCERN IS THE POTENTIAL FOR NON-SUPERCELL TORNADOES/
LANDSPOUTS THIS AFTERNOON. OVER THE LAST WEEK THERE HAVE BEEN TWO
LANDSPOUTS NEAR CHEYENNE AND TODAY LOOKS LIKE A VERY FAVORABLE SET
UP FOR MORE LANDSPOUT TYPE TORNADOES IN SOUTHEAST WYOMING EAST OF
THE LARAMIE RANGE. LAPSE RATES BY EARLY THIS AFTERNOON WILL
EXCEED 7 DEG/KG IN THE BOUNDARY LAYER WHILE 0-3 KM CAPE VALUES
WILL EXCEED 100 J/KG WHICH IS QUITE HIGH FOR THE 0-3 KM LAYER. THE
ONLY OTHER NEEDED INGREDIENT WILL BE A BOUNDARY TO FORM ON. MODELS
DO INDICATE A BOUNDARY NEAR OR JUST EAST OF THE LARAMIE RANGE...SO
THAT WILL BE SOMETHING TO WATCH AS WELL AS ANY OUTFLOW BOUNDARIES
THAT MAY INTERSECT OR INITIATE CONVECTION.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 439 AM MDT WED AUG 7 2013
THURSDAY NIGHT...ISOLATED TO SCATTERED EVENING THUNDERSTORMS ON TAP
ALONG AND WEST OF INTERSTATE 25 IN A LOW AND MID LEVEL THETA-E RIDGE
AXIS WITH DECENT THETA-E ADVECTION. CONVECTION WILL WANE AFTER
MIDNIGHT WITH LOSS OF DAYTIME HEATING AND WITH LESS LIFT FROM
MESOSCALE MECHANISMS.
FRIDAY...WILL SEE AN INCREASE IN AFTERNOON AND EVENING THUNDERSTORM
COVERAGE AS A PASSING SHORTWAVE TROUGH ALOFT AIDS IN DEVELOPMENT OF
MECHANICAL UPSLOPE SOUTHEAST LOW LEVEL WINDS ADVECTING INCREASING
MOISTURE INTO OUR COUNTIES. BULK OF COVERAGE WILL STRETCH FROM
DOUGLAS TO RAWLINS IN CLOSE PROXIMITY TO THE LOW AND MID LEVEL
THETA-E RIDGE AXIS.
SATURDAY/SUNDAY...LESS THUNDERSTORM COVERAGE AS LOW AND MID LEVEL
MOISTURE AND THUNDERSTORM FUEL DECREASES...ALONG WITH WARMING
TEMPERATURES ALOFT ACTING TO PROVIDE MORE CONVECTIVE
INHIBITION...CIN.
MONDAY/TUESDAY...RIDGING ALOFT PREVAILS...LIMITING AFTERNOON AND
EVENING THUNDERSTORM COVERAGE. HOWEVER...PERSISTENCE OF LOW LEVEL
UPSLOPE AND DIFFERENTIAL HEATING WILL AID IN AT LEAST ISOLATED LATE
DAY THUNDERSTORMS EACH DAY...PRIMARILY ALONG THE UPSLOPE FAVORED
LOCALES ALONG AND EAST OF THE LARAMIE RANGE AND THE INTERSTATE 25
CORRIDOR.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY MORNING)
ISSUED AT 1046 AM MDT WED AUG 7 2013
LOOKS LIKE ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS FOR THIS
AFTERNOON. LATEST HRRR FORECAST SHOWING THUNDERSTORMS FORMING
ALONG A LINE JUST NORTH OF CHADRON OVER TO LUSK AROUND
19Z...SWEEPING SOUTH THROUGH THE SOUTHERN PANHANDLE BY
00Z. BASED TIMING ON ITS FORECAST. THEN BEHIND THE LINE...WE SEE A
NORTHEAST WIND DEVELOPING BEHIND THIS LINE. HRRR AND SREF SHOWING
A FAIRLY WIDESPREAD AND PROLONGED LOW CEILING EVENT WITH THESE
NORTHEAST UPSLOPING WINDS. BELIEVE THE MOST PROBABLE AREA WILL BE
HERE AT KCYS AND KSNY IN THE SOUTHERN PANHANDLE. BUT KAIA AND KBFF
COULD ALSO BE IMPACTED. SHOULD THESE AIRPORTS AND THE PANHANDLE
RECEIVE GOOD RAINFALL TODAY...THEN CONFIDENCE WILL CERTAINLY GROW
THAT IT WILL HAPPEN.
&&
.FIRE WEATHER...
ISSUED AT 439 AM MDT WED AUG 7 2013
ACTIVE WEATHER PATTERN WILL CONTINUE INTO THE FORESEEABLE FUTURE.
MAIN CHANCES FOR RAIN WILL BE ALONG AND EAST OF THE LARAMIE RANGE
WITH LESS CHANCES TO THE WEST. MARGINAL CRITICAL FIRE CONDITIONS
WILL OCCUR A FEW DAYS OVER CARBON COUNTY OTHERWISE HUMIDITY
VALUES WILL BE ON THE HIGH SIDE THROUGH EARLY NEXT WEEK.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
UPDATE...WEILAND
SHORT TERM...LIEBL
LONG TERM...RUBIN
AVIATION...CLAYCOMB
FIRE WEATHER...LIEBL
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
201 AM EDT FRI AUG 9 2013
.UPDATE...
THE LONG TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 332 PM EDT THU AUG 8 2013
WEAK DIFFUSE FRONTAL BOUNDARY WILL SAG SOUTH THROUGH THE REGION INTO
FRIDAY AS SEVERAL SURFACE WAVES RIPPLE ALONG THE BOUNDARY. THIS WILL
KEEP SCATTERED SHOWERS AND THUNDERSTORMS ACROSS CENTRAL INDIANA INTO
FRIDAY...AND OVER SOUTHERN PORTIONS OF THE AREA INTO EARLY SATURDAY
AS THE FRONT MAKES ONLY SLOW PROGRESS SOUTH INTO THE TENNESSEE
VALLEY. HIGH PRESSURE DRIFTING THROUGH THE GREAT LAKES WILL BRING
DRIER AND SLIGHTLY COOLER WEATHER SATURDAY AND SUNDAY. A COLD FRONT
WILL PASS THROUGH THE AREA EARLY NEXT WEEK WITH RAIN...FOLLOWED BY
REINFORCING SHOT OF COOLER AIR BY MIDWEEK AS THE UPPER TROUGH
DEEPENS OVER THE EASTERN U S.
&&
.NEAR TERM /REST OF TONIGHT/...
ISSUED AT 953 PM EDT THU AUG 8 2013
SHOWERS AND THUNDERSTORMS HAVE BECOME MORE NUMEROUS LAST FEW HOURS
ACROSS OUR SOUTH AS MCV APPROACHES. RAPID REFRESH FOLLOWS THIS IDEAL
WITH NUMEROUS SHOWERS AND THUNDERSTORMS ACROSS OUR SOUTH THROUGH
ABOUT 06Z AND WITH MUCH LESS ACTIVITY AFTER THAT. ALSO CONCERNED
ABOUT HEAVY RAIN POTENTIAL NEXT SEVERAL HOURS AS PRECIPITABLE WATER
RUNNING ABOUT 2 TO 2.2 INCHES. WILL CONSIDER AREAL FLOOD ADVISORIES
IN SOME AREAS TO COVER THIS.
FARTHER NORTH...CURRENT FORECAST SEEMS TO BE ON TRACK. COLD FRONT WILL
MOVE SLOWLY SOUTH ACROSS OUR AREA OVERNIGHT. NAM SEEMS TO COOL TEMPERATURES
ACROSS OUR NORTHWEST TOO MUCH BY DAYBREAK. MADE A FEW TWEAKS IN
TEMPERATURES FROM PREVIOUS FORECAST. BUT IN MOST AREAS THEY SEEM OK.
PREVIOUS NEAR TERM DISCUSSION FOLLOWS...
MESOLOW RESIDES ACROSS NORTHERN COUNTIES WITH THE FRONTAL BOUNDARY
EXTENDING SOUTHWEST INTO EAST CENTRAL ILLINOIS. LINEAR CONVECTION
HAS DEVELOPED ALONG A DIFFUSE FRONT TO THE WEST OF THE INDY
METRO...WITH ADDITIONAL CONVECTION NOW BEGINNING TO DEVELOP IN
VICINITY OF THE BOUNDARY OVER SOUTH CENTRAL ILLINOIS. MUGGY
AFTERNOON IN PROGRESS AS TEMPS HAVE RISEN INTO THE MID 80S OVER ALL
BUT FAR NORTHERN COUNTIES.
COMPLEX AND LOW CONFIDENCE FORECAST FOR THE REST OF THE AFTERNOON
AND TONIGHT AS THE PRESENCE OF THE BOUNDARY SLOWLY SAGGING SOUTH
THROUGH THE FORECAST AREA AND THE APPROACHING REMNANT MCV NEAR KSTL
ARE LIKELY TO BE FACTORS IN CONVECTIVE COVERAGE INTO THE OVERNIGHT.
HRRR HANDLING CURRENT CONVECTIVE COVERAGE REASONABLY WELL AND WAS
USED AS A START FOR THE NEXT SEVERAL HOURS.
CURRENT MESOANALYSIS INDICATES AIRMASS HAS SUFFICIENTLY DESTABILIZED
ALONG AND IMMEDIATELY AHEAD OF THE BOUNDARY. MUCH OF THE CONVECTION
HAS WEAKENED WITHIN THE VICINITY OF THE WELL DEFINED MCV OVER
EASTERN MISSOURI. HOWEVER AS THIS FEATURE CONTINUES TO APPROACH
CENTRAL INDIANA OVER THE NEXT SEVERAL HOURS AND INTERACTS WITH THE
UNSTABLE AND VERY MOIST AIRMASS OVER THE REGION...EXPECT AN INCREASE
IN CONVECTIVE COVERAGE INTO THE EVENING...LIKELY CONTINUING
OVERNIGHT AS THE MCV MOVES THROUGH THE REGION. BOTH THE RAP AND 12Z
GFS HINT AT THE LOW LEVEL JET REESTABLISHING ALONG THE OHIO RIVER
TONIGHT...WITH A LOW LEVEL BAROCLINIC ZONE SETTING UP ACROSS
SOUTHERN PORTIONS OF THE FORECAST AREA. THINK ULTIMATELY SHOULD THIS
COME TO PASS...THE HEAVIEST RAINFALL WILL SET UP OVER SOUTHERN
COUNTIES OVERNIGHT AND WILL CARRY HIGHEST POPS IN THESE AREAS.
IMPRESSIVE PRECIP WATER VALUES IN EXCESS OF 2 INCHES COMBINED WITH
STORM MOTIONS UNDER 10KTS AND STEERING CURRENTS PARALLEL TO THE
BOUNDARY ARE SUPPORTIVE OF TORRENTIAL RAINFALL...BACKBUILDING AND
TRAINING ECHOES AND POTENTIAL FOR LOCALIZED FLOODING. WITH 1 HR/3 HR
FLASH FLOOD GUIDANCE VALUES IN EXCESS OF 2 INCHES/2.5-3.5 INCHES AND
UNCERTAINTY IN HOW EXTENSIVE THE PRECIP COVERAGE BECOMES...HAVE NO
PLANS TO ISSUE A FLASH FLOOD WATCH AT THIS TIME.
TEMPS...WARMER MAVMOS LOOKS REASONABLE CONSIDERING HIGH LOW LEVEL
MOISTURE PRESENT OVER THE REGION. NAM APPEARS TO BE ADVECTING DRIER
AIR INTO THE REGION TOO AGGRESSIVELY EARLY FRIDAY AND THIS IS LIKELY
IMPACTING MET GUIDANCE LOWS.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
ISSUED AT 332 PM EDT THU AUG 8 2013
FORECAST CHALLENGES REMAIN ON PRECIP CHANCES INTO EARLY SATURDAY AS
THE FRONTAL BOUNDARY MAKES ONLY SLOW PROGRESS SOUTH.
REMNANT MCV AND A WEAK SURFACE WAVE WILL BE SHIFTING EAST OF THE
REGION BY 12Z FRIDAY. FOCUS FOR ADDITIONAL CONVECTIVE DEVELOPMENT
WILL BE SOUTH OF I-70 AS THE BOUNDARY SETTLES OVER SOUTHERN INDIANA
BY FRIDAY AFTERNOON. WILL ONCE AGAIN FOCUS HIGHEST POPS OVER
SOUTHERN COUNTIES WITH LOW CHANCE POPS NORTH OF I-70 AS SLIGHTLY
DRIER AIR BEGINS TO EXPAND SOUTH FROM THE GREAT LAKES. THE BOUNDARY
WILL CONTINUE TO SHIFT SOUTH THROUGH KENTUCKY ON FRIDAY NIGHT AS AN
UPPER LOW PIVOTS SOUTH OF JAMES BAY AND INTRODUCES A BROAD UPPER
LEVEL TROUGH OVER THE EASTERN U S. WILL HANG ONTO LOW CHANCE POPS
OVER SOUTHERN COUNTIES FRIDAY NIGHT AND EARLY SATURDAY DUE TO THE
CLOSE PROXIMITY OF THE BOUNDARY...BUT OVERALL TREND INTO SATURDAY
SHOULD BE TOWARDS DRIER AND SLIGHTLY COOLER AIR EXPANDING INTO THE
FORECAST AREA AS THE DEEPER MOISTURE IS PUSHED SOUTH.
SURFACE HIGH PRESSURE WILL BUILD ACROSS THE LOWER GREAT LAKES
SATURDAY AFTERNOON THROUGH SUNDAY WITH DRY WEATHER. LOW LEVEL
MOISTURE ATTEMPTS TO IMMEDIATELY RETURN BACK NORTH INTO THE OHIO
VALLEY SUNDAY AFTERNOON AS THE HIGH SHIFTS AWAY TO THE EAST. HAVE
KEPT DRY CONDITIONS THROUGH 00Z MONDAY AS LITTLE FORCING ALOFT
PRESENT...ALTHOUGH WILL HAVE TO MONITOR FOR ISOLATED SHOWERS OVER
THE LOWER WABASH VALLEY AS INSTABILITY AXIS WILL BE CLOSE BY ACROSS
THE LOWER OHIO VALLEY.
TEMPS...MOS GUIDANCE IN GENERAL WORKS WELL CONSIDERING LOW LEVEL
THERMALS THROUGHOUT THE PERIOD. HIGH TEMPS FRIDAY AND SATURDAY WILL
BE HIGHLY DEPENDENT ON CLOUD COVER...BUT GENERALLY LOOKING AT LOW TO
MID 80S BOTH DAYS...SLIGHTLY COOLER WHERE RAIN/CLOUDS IMPACT. CORE
OF THE COOLER AIR ASSOCIATED WITH THE UPPER TROUGH LIKELY DELAYED TO
SUNDAY AS 850MB TEMPS FALL TO AROUND 11C. LOCATIONS SUNDAY SHOULD
REMAIN IN THE UPPER 70S AND LOWER 80S.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
ISSUED AT 200 AM EDT FRI AUG 9 2013
ENSEMBLES INDICATE A RATHER STABLE WEATHER PATTERN DURING THIS
PERIOD. SUBTROPICAL RIDGE REMAINS ALONG THE GULF COAST/SOUTHERN
PLAINS REGION...WHILE UPPER TROUGHING CONTINUES OVER THE NORTHEAST
PARTS OF THE COUNTRY.
ENSEMBLES SUGGEST AN UPPER DISTURBANCE MAY MOVE ACROSS THE AREA
EARLY NEXT WEEK...AROUND MONDAY AND TUESDAY. WILL CONTINUE WITH
CHANCE POPS AT THOSE TIMES. PRECIPITATION THREAT DIMINISHES BY NEXT
WEDNESDAY AND THURSDAY WITH THE ENSEMBLES SHOWING LITTLE TO NO QPF
POTENTIAL BY THEN. WILL GO DRY AFTER TUESDAY.
&&
.AVIATION /DISCUSSION FOR THE 09/0600Z TAFS/...
ISSUED AT 1233 AM EDT FRI AUG 9 2013
RAIN SHOWERS REMAIN CONFINED TO KBMG AND KHUF...SO WILL ONLY CARRY
MENTION OF VCSH AT THOSE TAF SITES THROUGH FRI 08Z. MVFR CONDITIONS
WILL BE LIKELY AT ALL TAF SITES THOUGH EARLY THIS MORNING DUE TO LOW
CEILINGS AND FOG FORMATION WITH MOIST AIRMASS IN PLACE.
HOWEVER...THE FRONTAL BOUNDARY THAT IS GENERATING THE CURRENT WEAK
CONVECTION OVER SOUTHERN TAF SITES WILL SHIFT FURTHER SOUTH LATER
TODAY...ALLOWING DRIER AIR TO FILTER INTO TAF SITES AND A RETURN TO
VFR CONDITIONS BY THIS AFTERNOON. WINDS WILL BE NORTHERLY AT 2 TO 8
KTS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN/JH
SHORT TERM...RYAN
LONG TERM....JAS
AVIATION...TDUD
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AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1233 AM EDT FRI AUG 9 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 332 PM EDT THU AUG 8 2013
WEAK DIFFUSE FRONTAL BOUNDARY WILL SAG SOUTH THROUGH THE REGION INTO
FRIDAY AS SEVERAL SURFACE WAVES RIPPLE ALONG THE BOUNDARY. THIS WILL
KEEP SCATTERED SHOWERS AND THUNDERSTORMS ACROSS CENTRAL INDIANA INTO
FRIDAY...AND OVER SOUTHERN PORTIONS OF THE AREA INTO EARLY SATURDAY
AS THE FRONT MAKES ONLY SLOW PROGRESS SOUTH INTO THE TENNESSEE
VALLEY. HIGH PRESSURE DRIFTING THROUGH THE GREAT LAKES WILL BRING
DRIER AND SLIGHTLY COOLER WEATHER SATURDAY AND SUNDAY. A COLD FRONT
WILL PASS THROUGH THE AREA EARLY NEXT WEEK WITH RAIN...FOLLOWED BY
REINFORCING SHOT OF COOLER AIR BY MIDWEEK AS THE UPPER TROUGH
DEEPENS OVER THE EASTERN U S.
&&
.NEAR TERM /REST OF TONIGHT/...
ISSUED AT 953 PM EDT THU AUG 8 2013
SHOWERS AND THUNDERSTORMS HAVE BECOME MORE NUMEROUS LAST FEW HOURS
ACROSS OUR SOUTH AS MCV APPROACHES. RAPID REFRESH FOLLOWS THIS IDEAL
WITH NUMEROUS SHOWERS AND THUNDERSTORMS ACROSS OUR SOUTH THROUGH
ABOUT 06Z AND WITH MUCH LESS ACTIVITY AFTER THAT. ALSO CONCERNED
ABOUT HEAVY RAIN POTENTIAL NEXT SEVERAL HOURS AS PRECIPITABLE WATER
RUNNING ABOUT 2 TO 2.2 INCHES. WILL CONSIDER AREAL FLOOD ADVISORIES
IN SOME AREAS TO COVER THIS.
FARTHER NORTH...CURRENT FORECAST SEEMS TO BE ON TRACK. COLD FRONT WILL
MOVE SLOWLY SOUTH ACROSS OUR AREA OVERNIGHT. NAM SEEMS TO COOL TEMPERATURES
ACROSS OUR NORTHWEST TOO MUCH BY DAYBREAK. MADE A FEW TWEAKS IN
TEMPERATURES FROM PREVIOUS FORECAST. BUT IN MOST AREAS THEY SEEM OK.
PREVIOUS NEAR TERM DISCUSSION FOLLOWS...
MESOLOW RESIDES ACROSS NORTHERN COUNTIES WITH THE FRONTAL BOUNDARY
EXTENDING SOUTHWEST INTO EAST CENTRAL ILLINOIS. LINEAR CONVECTION
HAS DEVELOPED ALONG A DIFFUSE FRONT TO THE WEST OF THE INDY
METRO...WITH ADDITIONAL CONVECTION NOW BEGINNING TO DEVELOP IN
VICINITY OF THE BOUNDARY OVER SOUTH CENTRAL ILLINOIS. MUGGY
AFTERNOON IN PROGRESS AS TEMPS HAVE RISEN INTO THE MID 80S OVER ALL
BUT FAR NORTHERN COUNTIES.
COMPLEX AND LOW CONFIDENCE FORECAST FOR THE REST OF THE AFTERNOON
AND TONIGHT AS THE PRESENCE OF THE BOUNDARY SLOWLY SAGGING SOUTH
THROUGH THE FORECAST AREA AND THE APPROACHING REMNANT MCV NEAR KSTL
ARE LIKELY TO BE FACTORS IN CONVECTIVE COVERAGE INTO THE OVERNIGHT.
HRRR HANDLING CURRENT CONVECTIVE COVERAGE REASONABLY WELL AND WAS
USED AS A START FOR THE NEXT SEVERAL HOURS.
CURRENT MESOANALYSIS INDICATES AIRMASS HAS SUFFICIENTLY DESTABILIZED
ALONG AND IMMEDIATELY AHEAD OF THE BOUNDARY. MUCH OF THE CONVECTION
HAS WEAKENED WITHIN THE VICINITY OF THE WELL DEFINED MCV OVER
EASTERN MISSOURI. HOWEVER AS THIS FEATURE CONTINUES TO APPROACH
CENTRAL INDIANA OVER THE NEXT SEVERAL HOURS AND INTERACTS WITH THE
UNSTABLE AND VERY MOIST AIRMASS OVER THE REGION...EXPECT AN INCREASE
IN CONVECTIVE COVERAGE INTO THE EVENING...LIKELY CONTINUING
OVERNIGHT AS THE MCV MOVES THROUGH THE REGION. BOTH THE RAP AND 12Z
GFS HINT AT THE LOW LEVEL JET REESTABLISHING ALONG THE OHIO RIVER
TONIGHT...WITH A LOW LEVEL BAROCLINIC ZONE SETTING UP ACROSS
SOUTHERN PORTIONS OF THE FORECAST AREA. THINK ULTIMATELY SHOULD THIS
COME TO PASS...THE HEAVIEST RAINFALL WILL SET UP OVER SOUTHERN
COUNTIES OVERNIGHT AND WILL CARRY HIGHEST POPS IN THESE AREAS.
IMPRESSIVE PRECIP WATER VALUES IN EXCESS OF 2 INCHES COMBINED WITH
STORM MOTIONS UNDER 10KTS AND STEERING CURRENTS PARALLEL TO THE
BOUNDARY ARE SUPPORTIVE OF TORRENTIAL RAINFALL...BACKBUILDING AND
TRAINING ECHOES AND POTENTIAL FOR LOCALIZED FLOODING. WITH 1 HR/3 HR
FLASH FLOOD GUIDANCE VALUES IN EXCESS OF 2 INCHES/2.5-3.5 INCHES AND
UNCERTAINTY IN HOW EXTENSIVE THE PRECIP COVERAGE BECOMES...HAVE NO
PLANS TO ISSUE A FLASH FLOOD WATCH AT THIS TIME.
TEMPS...WARMER MAVMOS LOOKS REASONABLE CONSIDERING HIGH LOW LEVEL
MOISTURE PRESENT OVER THE REGION. NAM APPEARS TO BE ADVECTING DRIER
AIR INTO THE REGION TOO AGGRESSIVELY EARLY FRIDAY AND THIS IS LIKELY
IMPACTING MET GUIDANCE LOWS.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
ISSUED AT 332 PM EDT THU AUG 8 2013
FORECAST CHALLENGES REMAIN ON PRECIP CHANCES INTO EARLY SATURDAY AS
THE FRONTAL BOUNDARY MAKES ONLY SLOW PROGRESS SOUTH.
REMNANT MCV AND A WEAK SURFACE WAVE WILL BE SHIFTING EAST OF THE
REGION BY 12Z FRIDAY. FOCUS FOR ADDITIONAL CONVECTIVE DEVELOPMENT
WILL BE SOUTH OF I-70 AS THE BOUNDARY SETTLES OVER SOUTHERN INDIANA
BY FRIDAY AFTERNOON. WILL ONCE AGAIN FOCUS HIGHEST POPS OVER
SOUTHERN COUNTIES WITH LOW CHANCE POPS NORTH OF I-70 AS SLIGHTLY
DRIER AIR BEGINS TO EXPAND SOUTH FROM THE GREAT LAKES. THE BOUNDARY
WILL CONTINUE TO SHIFT SOUTH THROUGH KENTUCKY ON FRIDAY NIGHT AS AN
UPPER LOW PIVOTS SOUTH OF JAMES BAY AND INTRODUCES A BROAD UPPER
LEVEL TROUGH OVER THE EASTERN U S. WILL HANG ONTO LOW CHANCE POPS
OVER SOUTHERN COUNTIES FRIDAY NIGHT AND EARLY SATURDAY DUE TO THE
CLOSE PROXIMITY OF THE BOUNDARY...BUT OVERALL TREND INTO SATURDAY
SHOULD BE TOWARDS DRIER AND SLIGHTLY COOLER AIR EXPANDING INTO THE
FORECAST AREA AS THE DEEPER MOISTURE IS PUSHED SOUTH.
SURFACE HIGH PRESSURE WILL BUILD ACROSS THE LOWER GREAT LAKES
SATURDAY AFTERNOON THROUGH SUNDAY WITH DRY WEATHER. LOW LEVEL
MOISTURE ATTEMPTS TO IMMEDIATELY RETURN BACK NORTH INTO THE OHIO
VALLEY SUNDAY AFTERNOON AS THE HIGH SHIFTS AWAY TO THE EAST. HAVE
KEPT DRY CONDITIONS THROUGH 00Z MONDAY AS LITTLE FORCING ALOFT
PRESENT...ALTHOUGH WILL HAVE TO MONITOR FOR ISOLATED SHOWERS OVER
THE LOWER WABASH VALLEY AS INSTABILITY AXIS WILL BE CLOSE BY ACROSS
THE LOWER OHIO VALLEY.
TEMPS...MOS GUIDANCE IN GENERAL WORKS WELL CONSIDERING LOW LEVEL
THERMALS THROUGHOUT THE PERIOD. HIGH TEMPS FRIDAY AND SATURDAY WILL
BE HIGHLY DEPENDENT ON CLOUD COVER...BUT GENERALLY LOOKING AT LOW TO
MID 80S BOTH DAYS...SLIGHTLY COOLER WHERE RAIN/CLOUDS IMPACT. CORE
OF THE COOLER AIR ASSOCIATED WITH THE UPPER TROUGH LIKELY DELAYED TO
SUNDAY AS 850MB TEMPS FALL TO AROUND 11C. LOCATIONS SUNDAY SHOULD
REMAIN IN THE UPPER 70S AND LOWER 80S.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
ISSUED AT 229 PM EDT THU AUG 8 2013
MODELS ARE SIMILAR ENOUGH THAT THE ALLBLEND INITIALIZATION CAN BE
USED FOR MOST ITEMS IN THE LONG TERM.
UPPER TROUGH WILL DEEPEN ACROSS THE AREA IN THE EXTENDED. THIS WILL
KEEP CENTRAL INDIANA IN COOLER NORTHWEST FLOW. TEMPERATURES WILL
REMAIN BELOW AVERAGE THROUGH THE PERIOD.
A COLD FRONT WILL WORK ITS WAY SOUTH MONDAY INTO TUESDAY BRINGING
THE COOLER AIR TO THE AREA. MODELS AND SOME ENSEMBLES ARE SHOWING
CHANCES FOR RAIN LINGERING INTO TUESDAY WITH SOME TIMING DIFFERENCES
BETWEEN THEM. GIVEN THE UNCERTAINTIES INVOLVED WILL GO WITH
ALLBLEND/S CHANCES FOR RAIN MONDAY INTO TUESDAY...BUT AT THE MOMENT
&&
.AVIATION /DISCUSSION FOR THE 09/0600Z TAFS/...
ISSUED AT 1233 AM EDT FRI AUG 9 2013
RAIN SHOWERS REMAIN CONFINED TO KBMG AND KHUF...SO WILL ONLY CARRY
MENTION OF VCSH AT THOSE TAF SITES THROUGH FRI 08Z. MVFR CONDITIONS
WILL BE LIKELY AT ALL TAF SITES THOUGH EARLY THIS MORNING DUE TO LOW
CEILINGS AND FOG FORMATION WITH MOIST AIRMASS IN PLACE.
HOWEVER...THE FRONTAL BOUNDARY THAT IS GENERATING THE CURRENT WEAK
CONVECTION OVER SOUTHERN TAF SITES WILL SHIFT FURTHER SOUTH LATER
TODAY...ALLOWING DRIER AIR TO FILTER INTO TAF SITES AND A RETURN TO
VFR CONDITIONS BY THIS AFTERNOON. WINDS WILL BE NORTHERLY AT 2 TO 8
KTS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN/JH
SHORT TERM...RYAN
LONG TERM....50
AVIATION...TDUD
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS DES MOINES IA
325 AM CDT FRI AUG 9 2013
.SHORT TERM.../TODAY /...
ISSUED AT 313 AM CDT FRI AUG 9 2013
WEAK COLD FRONTAL BOUNDARY EXTENDING FROM FROM MN INTO NWRN IA INTO
KS WILL MOVE SOUTHEAST AND EXIT THE CWA BY AROUND MID DAY. SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS OCCURRING ALONG THE FRONT WILL
CONTINUE TO MOVE ESEWD WITH THE FRONT HRRR HAS A PRETTY DECENT
HANDLE ON THE PRECIP AND SUGGESTS THE PRECIP WILL BE OUT OF THE CWA
BY AROUND 18Z. HIGH PRESSURE WILL BEGIN BUILDING INTO THE STATE
THIS AFTERNOON FROM THE NORTHWEST.
.LONG TERM.../TONIGHT THROUGH THURSDAY/...
ISSUED AT 313 AM CDT FRI AUG 9 2013
SIMILAR CHALLENGES COMING UP COMPARED TO PAST FEW DAYS. APPROACHING
SHORT WAVES AND SYNOPTIC FEATURES REMAIN RATHER WEAK GIVEN TIME OF
YEAR AND QUESTIONS REVOLVING AROUND COVERAGE AND CHANCES FOR RAIN IN
THE FORECAST. FOR NOW...WEAK BOUNDARY WILL BE SOUTH OF THE REGION BY
THIS EVENING AND DRY WEATHER EXPECTED THROUGH LATE SATURDAY NIGHT.
FINALLY ON SUNDAY ANOTHER NORTHERN STREAM WAVE WILL ATTEMPT TO CROSS
THE AREA WITH SOME MOISTURE ASSOCIATED WITH IT. THIS WILL ONCE AGAIN
BRING CHANCES FOR SHOWERS AND THUNDERSTORMS TO THE AREA SUNDAY INTO
MONDAY AFTERNOON. FOLLOWING THAT HIGH PRESSURE WILL DROP SOUTH OUT
OF CANADA AND KEEP TEMPERATURES COMFORTABLE IN THE UPPER 70S TO
LOWER 80S WITH SLIGHTLY COOLER READINGS OVER THE NORTH. OVERALL
QUITE PLEASANT FOR AUGUST...THOUGH A BIT BELOW NORMAL. MOST OF THE
MED RANGE MODELS SUGGEST THAT THE HIGH OVER THE GREAT LAKES WILL
REMAIN ANCHORED THERE UNTIL MID TO LATE NEXT WEEK. FOR THE MOST PART
OUR WEATHER WILL REMAIN RATHER UNEVENTFUL WITH DRIER AND COOLER THAN
NORMAL CONDITIONS.
&&
.AVIATION...09/06Z
ISSUED AT 1149 PM CDT THU AUG 8 2013
VFR CONDITIONS WILL PREVAIL THROUGHOUT THE ENTIRE FORECAST AREA AS
HIGH PRESSURE DOMINATES THE PATTERN.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...MS
LONG TERM...REV
AVIATION...PODRAZIK
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
305 AM CDT FRI AUG 9 2013
.SYNOPSIS...
ISSUED AT 303 AM CDT FRI AUG 9 2013
06Z SFC ANALYSIS HAS WEAK LOWS ASSOCIATED WITH A FRONTAL BOUNDARY IN
THE OHIO VALLEY WITH A THUNDERSTORM COMPLEX ACROSS OKLAHOMA. A WEAK
FRONT/BOUNDARY RAN FROM EASTERN LAKE SUPERIOR...TO KYKN...AND THEN
ACROSS SOUTHERN SOUTH DAKOTA. RADAR HAS WEAK RETURNS ACROSS CENTRAL
IOWA MAINLY IN THE FORM OF SPRINKLES AND SLIGHTLY STRONGER RETURNS
ACROSS NORTHERN IOWA NEAR THE BOUNDARY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 303 AM CDT FRI AUG 9 2013
THE WEAK RETURNS ACROSS CENTRAL AND SOUTHERN IOWA IS OCCURRING FROM
A MID LEVEL CLOUD DECK AND IS LIKELY SPRINKLES. THE BETTER RADAR
RETURNS ALONG THE MN/IA BORDER IS IN AN AREA OF BETTER LIFT.
HOWEVER...THIS LIFT IS PROGGED TO WEAKEN THROUGH SUNRISE PER TRENDS
FROM THE RAP AND OTHER MODELS. RECENT RADAR TRENDS SEEM TO SUPPORT
THIS SCENARIO WITH NOT ONLY THE NORTHERN RADAR RETURNS BUT THE
SOUTHERN RADAR RETURNS.
THUS MAYBE SOME SPRINKLES MAY ENTER THE FAR WESTERN/NORTHWEST PARTS
OF THE CWFA PRIOR TO SUNRISE BEFORE DISSIPATING.
THE WEAK FRONT/BOUNDARY SLOWLY MOVES THROUGH THE CWFA DURING THE
DAY. LIFT IS VERY WEAK AND THE BETTER MOISTURE IS SOUTH OF THE AREA.
THUS ISOLATED SPRINKLES ARE THE MORE PROBABLE PRECIPITATION TYPE
DURING THE DAY. POSSIBLY A COUPLE OF ISOLATED DIURNAL SHOWERS MAY
DEVELOP DURING THE AFTERNOON WHEN HEATING IS THE STRONGEST.
TONIGHT...ANY SPRINKLES/DIURNAL SHOWERS THAT DEVELOP WILL DISSIPATE
WITH SUNSET LEAVING THE REMAINDER OF THE NIGHT DRY AS HIGH PRESSURE
BUILDS INTO THE MIDWEST. THE MCS TOOL POINTS TO THE BETTER SUPPORT
BEING SOUTH OF THE CWFA WHICH IS WHERE THE BETTER MOISTURE IS
LOCATED.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 303 AM CDT FRI AUG 9 2013
MAINLY DRY WITH NEAR TO SLIGHTLY BELOW NORMAL TEMPS AS NORTHWEST
FLOW ALOFT REMAINS IN PLACE OVER THE REGION.
SAT-SAT NGT... MORE FANTASTIC WEATHER FOR OUTDOOR ACTIVITIES WITH
SURFACE TO 850 MB HIGH PRESSURE RIDGE PROVIDING LIGHT NORTHERLY
WINDS USHERING IN DRIER AIR AND COMFORTABLE HUMIDITY WITH HIGHS
MAINLY IN RANGE OF 77-83F. LOWS SAT NGT MAINLY IN RANGE OF 57-63F
WITH SOME INTERVALS OF MID/HIGH CLOUDS FROM UPSTREAM CONVECTION
PARTS OF SD/MN/NW-N IA ATTENDANT TO SHORTWAVE AND ELEVATED WARM
MOIST ADVECTION NORTH OF SURFACE BOUNDARY.
SUN-MON... WEAK SHORTWAVE AND FRONTAL BOUNDARY TO RESULT IN CHC
OF PCPN. LACK OF DEEP MOISTURE AND WEAK FORCING SUGGESTED ATTIM
SUPPORTIVE OF MOSTLY LIGHT QPF AMOUNTS. PCPN CHC MAY HOLD OFF
UNTIL MON ACROSS THE SOUTHERN CWA WITH CONTINUED INFLUX OF
DRIER AIR FROM DEPARTING HIGH. BUT THEN ON MON... MAY SEE PCPN
SHIFT FROM THE NORTH AND FOCUS MORE ACROSS SOUTHERN CWA DEPENDING
ON TIMING OF BOUNDARY. EXPECT TEMPS TO RECOVER ON SUN TO AROUND
NORMAL WITH DEVELOPING SOUTH WINDS AND DEEPER MIXING TO JUST ABOVE
850 MB SUPPORTIVE OF HIGHS IN THE LOW TO MID 80S. HOWEVER... DEBRIS
CLOUDS IN FAR NORTH SUN COULD LIMIT HIGHS THERE IN THE 70S ALONG/N
OF HWY 20. SUN NGT WITH CLOUDS AND PRE-FRONTAL SOUTH WINDS SHOULD
YIELD MILDER LOWS IN THE 60S. MON WILL BE FEW TO SEVERAL DEGS
COOLER ON HIGHS WITH MAINLY UPPER 70S TO LOWER 80S DUE TO CLOUDS
AND FRONTAL PASSAGE.
TUE-THU... HIGH PRESSURE TO BECOME RE-ESTABLISHED ACROSS THE REGION
AND LIKELY REMAIN DOMINANT FEATURE THROUGH THE PERIOD KEEPING
TEMPS BELOW NORMAL AND DRY CONDITIONS WITH VERY COMFORTABLE HUMIDITY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1146 PM CDT THU AUG 8 2013
WEAK HIGH PRESSURE WILL KEEP VFR CONDITIONS FOR AT LEAST THE NEXT
24 HOURS. PASSING UPPER DISTURBANCES OVERNIGHT INTO MID MORNING WILL
PRODUCE BKN-OVC CLOUDS WITH BASES AOA 9K AGL. ISOLATED SPRINKLES
MAY OCCUR WITH NO RESTRICTION TO VISIBILITIES UNTIL 09/16Z. SKIES
WILL THEN BECOME MOSTLY CLEAR BY MID DAY. LIGHT WINDS TENDING TO
BE FROM THE NORTHEAST TONIGHT WILL SHIFT TO THE NORTHWEST AT 5 TO
10 MPH BY MID DAY FRIDAY.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...08
SHORT TERM...08
LONG TERM...05
AVIATION...NICHOLS
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
139 AM EDT Fri Aug 9 2013
...Updated Aviation Discussion...
...Forecast Update...
Issued at 1145 PM EDT Thu Aug 8 2013
One more quick update to match up areas of rain on 88D with the
forecast. Theta-E ridge axis now is focused along where the new
cells are developing in our southwest forecast area. Storms farther
north are progressing east nicely, limiting rainfall totals for now.
Issued at 944 PM EDT Thu Aug 8 2013
Did another quick update to increase PoP chances across southern
Indiana and far northern Kentucky for later this evening. Cluster
of ongoing showers and storms across southern Indiana is drifting a
little more southward now, with some backbuilding on the
southwestern flank. Extrapolated radar imagery suggests that this
could clip areas all the way south toward the Ohio River later this
evening. These showers and storms could affect the Louisville Metro
area around midnight EDT.
Secondary cluster of storms across northwest TN continues to trek
northeastward and is showing signs of gusting out to the northeast.
If these storms hold together, they could affect far southern
Kentucky after midnight as well.
Not much development off to the west at this time. However, latest
data continues to suggest that additional storms may develop to our
west and then head through central Kentucky overnight. It appears
that the models may be trying to develop convection in associated
with the nocturnal low-level jet axis. For now, have backed off
PoPs slightly in central Kentucky until after midnight and then have
let PoPs ramp up late. Rest of the forecast elements look good at
this time.
Update issued at 820 PM EDT Thu Aug 8 2013
Did a quick update to scale back precipitation chances for the next
few hours across much of Kentucky. Vorticity lobe continues to trek
eastward across Indiana this evening. Convection along the southern
edge of this boundary never really moved southward...but rather
eastward and looks to stay along and north of the I-64 corridor for
the next few hours. The best chances of rainfall in the near term
will be across our north edges of southern Indiana counties.
Secondary cluster of strong thunderstorms has rapidly intensified
across far eastern Arkansas and west Tennessee. This activity
continues to trek eastward and may affect the extreme southern
portions of our area toward the late evening hours. Additional
storms across east-central MO/IL are trying to develop. Latest
model data suggests this activity will further develop this evening
and then push into the region overnight. Will continue to go with
the higher PoPs for the later overnight period, but continue to
monitor the latest convective trends throughout the evening.
Update issued at 648 PM EDT Thu Aug 8 2013
Cluster of light to moderate rain showers continues to trek eastward
across portions of north-central Kentucky. This activity is
expected to continue for the next several hours, but should weaken
as it heads toward the I-75 corridor. More strongly forced
convection is rapidly developing on the southern side of a vorticity
max pushing eastward into Indiana. Storms are forming along a
differential heating and wind shift axis across southern Illinois.
This activity should continue to develop and track eastward along
the I-64 corridor this evening. Latest NAM and HRRR runs suggest
that this would impact north-central Kentucky during the overnight
period. Secondary area of storms is developing over southern MO and
northern AR, this activity will also head east, but may stay just
south of the forecast area late tonight.
With this update, have increased PoPs for the next few hours across
the central portions of the forecast area with the batch of
light-moderate rain moving through. Will continue to ramp up PoPs
tonight as the cluster of storms out to the west heads eastward into
the Ohio Valley.
.SHORT TERM (Now through Friday Night)...
Issued at 315 PM EDT Thu Aug 8 2013
An obstructed blocky flow continues over Canada late today with an
elongated west to east orientated 500mb low over Ontario and Quebec.
Farther south, a moderate westerly flow continues over the northern
Ohio Valley. Precipitable water values of near two inches or more
will continue through mid-day Friday, indicative of a tropical
airmass.
Quite a bit uncertainty still exists about where exactly convection
develops this evening. An circulation left over from last night`s
convection is now moving east northeast just to the south of St
Louis. This feature will move over southern Indiana late this
evening. This feature is supporting a cluster of thunderstorms now
moving east over western Kentucky. These storms are moving into an
unstable airmass southwest of Kentucky and should hold together
through this evening. Therefore, think storms late this afternoon
and early evening will become most numerous across west central
Kentucky, west of Interstate 65 and mostly to the south of
Interstate 64 across southern Indiana. A second area of convection
may drop south into south central Indiana late this evening. These
northern storms will form along a cold front slowly sagging south
across central Indiana. Will go likely for areas in Kentucky west of
Interstate 65 with scattered wording elsewhere.
Last night isolated storms over the Bluegrass produced very isolated
torrential rainfall amounts and flooding. This same scenario may play itself
out again tonight. Across south central Kentucky, localized heavy
rain and possible flooding are again possible in a few spots.
For Friday, a nearly stationary front will lie across southern
Indiana, nearly parallel to the Ohio River, any thunderstorm
development will highly depend on the location of any residual cloud
cover and outflow boundaries from overnight convection. Our best
moisture and convergence will lie over southern portions of our
Commonwealth. Slightly drier air will slowly filter in across
southern Indiana, limiting convective coverage there. Will continue
likely pops across southern Kentucky during the day Friday. Think
that any scattered storms will diminish across the north late
Friday, while hanging on near Tennessee.
Tonight will stay humid and muggy, with lows in the lower 70s, highs
Friday will reach the mid to upper 80s.
.LONG TERM (Saturday through Thursday)...
Issued at 309 PM EDT Thu Aug 8 2013
Quasi-stationary boundary laid out across the commonwealth will be
starting off this forecast period, allowing for the primary focus
for convection to be limited to southern portions of KY. Have
trended back PoPs for the northern half of the forecast area as such
since surface winds will have begun to back to the north by this
point, assuming the general deterministic model consensus holds
true. With the loss of daytime heating and as the front slowly
slides off to the south and east, have gone dry for the early
morning hours on Sunday. Couldn`t completely remove PoPs out of the
forecast for the afternoon hours as a surface low riding along the
frontal boundary traverses across from west to east, once again
serving as a focus for renewed convection chances as surface high
pressure centered over the southern Great Lakes fights for control
over us. This fight, however, is very short lived as the high moves
off toward the East Coast and the next frontal boundary approaches
the Ohio Valley. This front is seemingly much faster with strong
Canadian high pressure pushing it southward from behind. What this
translates to for us is a continued unsettled period from Monday
through Tuesday night. By Wednesday, am hopeful that the boundary
will be south of the TN border, although the 12Z GFS tries to keep
the southern tier of counties wet through Wednesday night. Even if
the timing ends up being slightly off, the end result will be the
same for all of us: clearing skies, a much drier airmass, and cool
temperatures for this time of year.
Speaking of temperatures, we`ll see highs ranging from the lower to
upper 80s throughout the entire period with the warmest day looking
to be Monday and the coolest day on Thursday. Dewpoints will keep it
muggy from this weekend through mid-week before a noticeable
difference comes in by Wednesday-Thursday. Lows will be near normal
Saturday night through Tuesday night, dropping off to below normal
by Wednesday night. Looking at 850mb anomalous temps on NCEP`s
ensemble, the cool temps are depicted to prevail under the
aforementioned high for much of the end of next week.
&&
.AVIATION (06Z TAF Update)...
Issued at 135 AM EDT Fri Aug 9 2013
Forecast remains lower confidence, given that timing of showers and
storms still is dependent on small scale features. The near term
forecast is relatively straightforward, but rains are all close to
the terminals, but not directly affecting them at this time. Best
growth appears to be along a line from just north of KBWG to south
of KFTK. Still think KBWG has a chance to get in on these storms
over the next few hours, with KLEX a couple hours downstream. In the
juicy atmosphere, showers can develop at almost any time, so have
left in the chance at KSDF as well. Some drier air will try and work
in from the north, slowly, which should limit coverage at KSDF by
mid morning and then by late in the day at KLEX. The actual front
that has been stalled to our north may make it to KSDF/KLEX this
evening, so have variable winds for now.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
Updates........RJS/MJ
Short Term.....JSD
Long Term......lg
Aviation.......RJS
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
401 AM EDT FRI AUG 9 2013
.SYNOPSIS...
HIGH PRESSURE WILL REMAIN OFFSHORE INTO THE WEEKEND...USHERING WARM
AND HUMID CONDITIONS INTO THE REGION. A COLD FRONT WILL SLOWLY
APPROACH FROM THE NORTHWEST FRIDAY INTO SATURDAY...EVENTUALLY
STALLING OVER NORTH CAROLINA ON SUNDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
THE LATEST WX ANALYSIS FEATURES A STRONG UPPER LOW SPINNING JEST
WEST OF ST JAMES BAY IN NORTHERN ONTARIO, WITH THE ASSOCIATED SFC
LOW OVER EASTERN QUEBEC. THE ATTENDANT SFC COLD FRONT EXTENDS
FROM UPSTATE NY BACK INTO THE LOWER OH VALLEY. ALOFT, FLAT W-SW
FLOW PREVAILS, IN BETWEEN STRONG HIGH PRESSURE JUST OFF THE
SOUTHEAST COAST AND STRONG UPPER LOW OVER NORTHERN CANADA. THIS
W-SW FLOW CONTINUES TO ADVECT MOISTURE DOWNSTREAM FROM A CONVOY
OF WEAK SHORTWAVE DISTURBANCES MOVING ALONG THE STALLED BOUNDARY.
PW VALUES REMAIN ~2.00 OVER THE MID- ATLANTIC REGION...AND SOLIDLY
IN THE 2-2.25" RANGE JUST WEST OF THE CENTRAL APPALACHIANS). SOME
SHOWERS PERSIST ALONG AND JUST W-NW OF THE AKQ CWA...LARGELY A
RESULT OF THE VERY MOIST AIRMASS. HOWEVER, VERY LITTLE IN THE WAY
OF AREAL COVERAGE THUS FAR OVER OUR REGION, WITH REGIONAL RADAR
REVEALING A MAJORITY OF THE ACTIVITY STILL WELL BACK NW FROM THE
OHIO VALLEY INTO CENTRAL PA AND THE NY HUDSON VALLEY.
FOR TODAY...
UPPER LOW JUST SOUTH OF HUDSON BAY WILL SLOWLY EDGE EWD TODAY
ACROSS THE ST LAWRENCE VALLEY OF QUEBEC. MEANWHILE, UPPER RIDGE
WILL AMPLIFY OFFSHORE OF THE SE CONUS. THIS WILL MAINTAIN MOIST
W-SW FLOW THROUGH THE DAY...BRINGING CONTINUED WARM AND HUMID
CONDITIONS. REGARDING PRECIPITATION CHANCES, WITH THE FRONT
ROUGHLY PARALLEL TO THE MID-UPPER FLOW, IT WILL CONTINUE TO MAKE
VERY SLOW EASTWARD PROGRESS TODAY. THUS, THE LOCAL AREA WL REMAIN
SEPARATED FROM THE MAIN AREA OF BROAD SCALE FORCING. HOWEVER, THE
WEST/DOWNSLOPE FLOW ALOFT WL AID IN THE DEVELOPMENT OF A PIEDMONT
LEE TROUGH, WHICH SHOULD BE THE FOCUS FOR A BIT MORE IN THE WAY OF
CONVECTIVE DEVELOPMENT THAN WE`VE SEEN THE PAST FEW DAYS. MAJORITY
OF THE ACTIVITY WILL REMAIN TO OUR NW. STILL, HRRR DOES FIRE UP
SOME CONVECTION ALONG A LLVL CONVERGENCE BOUNDARY...AND HV PRESERVED
HIGHEST POPS OUT THAT WAY, WITH LOWER POPS BACK TOWARD THE COASTAL
PLAIN. WL GO WITH A LOW END LIKELY POP OVER THE FAR NW, DROPPING
BACK TO A 30-50% POP FOR MUCH OF THE AREA BY MID AFTN. BEST RAIN
CHANCES ORIENTED NW OF A FARMVILLE-RICHMOND-CAMBRIDGE MD LINE.
FOR HIGHS, DESPITE PLENTY OF CLOUD COVER AND A RATHER MOIST
AIRMASS, INCREASING HEIGHTS COURTESY OF AMPLIFYING RIDGE SHOULD
ALLOW TEMPS TO RISE A DEGREE OR TWO FROM THOSE OF THURSDAY. HIGHS
GENERALLY IN THE LOWER 90S INLAND, UPPER 80S TO AROUND 90 COASTAL
AREAS.
TONIGHT...
GIVEN GENERALLY WEAK DYNAMICS, EXPECT MAJORITY OF CONVECTIVE
ACTIVITY TO WANE QUICKLY IN COVERAGE/INTENSITY WITH LOSS OF
HEATING/NOCTURNAL STABILITY. STILL, AS WE`VE SEEN THIS MORNING,
DOESN`T TAKE MUCH TO YIELD A FEW SHRAS IN AN AIRMASS THIS
MOIST...SO WILL RETAIN 30-40 POP FOR SCT SHRAS OVERNIGHT.
OTHERWISE A MOSTLY CLOUDY/MUGGY NIGHT IS EXPECTED WITH LOWS IN THE
LOW TO MID 70S.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
COLD FRONT WILL CONTINUE ITS VERY SLOW MOVEMENT SWWD TOWARDS THE
NRN MID ATLANTIC SAT...STRETCHING SWWD INTO THE MID MS VALLEY. AS
WE`VE SEEN THIS MORNING, WL SEE SEVERAL WAVES DEVELOP AND TRAIN ALONG
THE FRONTAL ZONE ON SAT AS SHORTWAVE ENERGY TRAVERSES THE W-SWLY
FLOW ALOFT. WILL HAVE HIGH END LIKELY POPS WEST OF THE CHES BAY
AS MID LEVEL SHORTWAVE ENERGY AND RRQ OF +70KT JET WL PROVIDE
NEEDED FORCING FOR ASCENT OVER THESE AREAS. HIGHLY ANOMALOUS
PRECIP WATER VALUES (+2 S.D.) AND CONTINUED MID-UPPER FLOW
PARALLEL TO THE SLOWLY SAGGING FRONT WILL INCREASE THE LIKELIHOOD
FOR SLOW MOVING STORMS AND LOCALLY HEAVY RAINFALL OVER THE
AREA...AND WL UPDATE TO MENTION HEAVY RAIN IN THIS MORNING`S HWO
IN ASSOCIATION WITH THIS EXPECTATION. LATEST DATA DOES CLEAR
NORTHERN ZONES BY SAT NIGHT, BUT EXPECT THAT THE FRONT WILL BECOME
STALLED ALONG/JUST NORTH OF THE VA/NC BORDER SAT NGT DUE TO
AFOREMENTIONED PARALLEL FLOW. ACCORDINGLY...KEPT POPS AT HIGH END
CHC (40-50%) ACROSS THE SOUTHERN TWO-THIRDS OF THE CWA SAT NIGHT
FOR CONTINUED SHRAS/TSTMS...WITH LOCALLY HVY RAINFALL REMAINING A
CONCERN INTO SUN MORN.
FOR TEMPS, EXPECT ANOTHER DAY OF ABOVE NORMAL TEMPS SAT (UPR
80S/LOW 90S INLAND...U80S AT THE COAST). MILD OVERNIGHT/EARLY
MORNING LOWS DUE TO MUGGY CONDITIONS AND PERIODS OF CLOUDS. LOWS
70-75.
SUNDAY...
00Z MODELS STALL THE SFC FRONT OVER NC ON SUNDAY. THE QUESTION
STILL REMAINS IS JUST HOW MUCH PCPN WILL LINGER ACROSS OUR CWA.
THE 12Z ECMWF LIMITS PCPN TO FAR SOUTHERN VA AND NE NC (GENERALLY
SOUTH OF THE VA HWY-58 CORRIDOR). MEANWHILE...THE 0Z GFS SHOWS A
STRONGER WAVE OF LOW PRESSURE DEVELOPING ALONG THE FRONT WHICH
BRINGS PCPN BACK INTO CENTRAL VA. BASED ON THE UNCERTAINTY...WILL
NOT SHUNT PCPN CHANCES AS FAR SOUTH AS THE SREF/ECMWF WOULD
SUGGEST...INSTEAD CARRING CHC POP/SCT T (30-50%) FOR ALL BUT THE MD
EASTERN SHORE INTO SUNDAY NIGHT. CONTINUED WARM AND HUMID WITH
HIGHS IN THE 80S.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
PATTERN NEXT WEEK WILL ALLOW FOR CONTINUED CHCS FOR SHRAS/TSRAS.
LONG TERM PERIOD STARTS OFF MON WITH CHCS FOR RAIN (30-40%) ALONG A
STALLED FRONTAL BOUNDARY OVER/JUST SOUTH OF THE LOCAL AREA. ZONAL FLOW
ALOFT WILL PREVENT THE FRONT FROM PUSHING SE OF THE AREA ERLY IN THE
WEEK...AND WITH CONTINUED DEEP MOISTURE THE CHC FOR RAIN WILL
CONTINUE INTO TUE DESPITE MARGINAL FORCING (MID-LVL ENERGY). AN
UPR-LVL TROF DIGS OVER THE ERN CONUS MID TO LATE WEEK AND FINALLY
FORCES THE FRONT OFFSHORE AS THE TROF PULLS OFF TO THE EAST.
TEMPS THRU THE PERIOD WILL AVG NEAR TO SLIGHTLY BELOW NORMAL...WITH
HIGHS RANGING THRU THE 80S AND LOWS IN THE 60S TO LWR 70S.
&&
.AVIATION /07Z FRIDAY THROUGH TUESDAY/...
SOUTH WINDS AROUND 5 KT HAVE KEPT THE LOWER ATMOSPHERE WELL-MIXED
AND WILL PREVENT ANY FOG FROM DEVELOPING TWD DAYBREAK. A LEE
TROUGH DEVELOPS OVER THE AREA TODAY AS A COLD FRONT IN THE OHIO
VALLEY APPROACHES THE MID ATLANTIC REGION. THIS TROUGH WILL
TIGHTEN THE PRESSURE GRADIENT AND ALSO PROVIDE A FOCUS FOR SHOWERS
AND THUNDERSTORMS THIS AFTERNOON INTO THIS EVENING. REGARDING
WINDS...SOUTH WINDS WILL BECOME BREEZY BY MID MORNING WITH GUSTS
OF 20-25 KT KICKING IN BY LATE MORNING/EARLY AFTERNOON. REGARDING
THUNDERSTORMS...MODERATE TO HEAVY RAINFALL AND LOCALIZED STRONG
WIND GUSTS WILL BE THE MAIN IMPACTS. SHOWERS AND STORMS WILL
DIMINISH IN INTENSITY AND COVERAGE OVERNIGHT WITH SOME STRAGGLING
SHOWERS POSSIBLE CLOSER TO THE COAST BY SATURDAY MORNING.
THE FRONT STALLS OVER SE VA ON SATURDAY...FOCUSING AFTERNOON
THUNDERSTORM ACTIVITY OVER THE SRN HALF OF VA AND NE NC INTO
SATURDAY EVENING. FOR SUNDAY INTO NEXT WEEK...THE STALLED FRONT
GRADUALLY PUSHES SOUTH OF THE AREA...HOWEVER PERIODS OF UNSETTLED
WEATHER SHOULD STILL BE ANTICIPATED AS MOISTURE AND ENERGY RIDE
ALONG THIS BOUNDARY.
&&
.MARINE...
A SFC TROUGH DEVELOPS BY THIS AFTN AHEAD OF AN APPROACHING COLD
FRONT. THIS FEATURE WILL CAUSE THE PRESSURE GRADIENT TO TIGHTEN AND
WILL ALSO PROVIDE A FOCUS FOR SHOWERS AND THUNDERSTORMS DURING THIS
AFTN AND EVENING. SOUTH WINDS THIS MORNING WILL TURN TO THE
SOUTHWEST BY THIS AFTERNOON AND AVERAGE 10-15 KT. GUSTS MAY REACH
20 KT AT TIMES OVER AREA WATERS (POSSIBLY UP TO 25 KT OUT NEAR
20 NM)...HOWEVER CONFIDENCE IS NOT HIGH ENOUGH TO ISSUE LOW-END SCA
FLAGS WITH THIS MORNING`S FORECAST ISSUANCE. WILL NEED TO MONITOR
TRENDS AS THE DAY UNFOLDS. REGARDLESS...LOCALLY STRONG WIND GUSTS
SHOULD BE ANTICIPATED IN THE VICINITY OF THUNDERSTORMS TODAY IN
ADDITION TO MODERATE TO HEAVY RAINFALL. SCA MAY BE POSSIBLE
OVERNIGHT TONIGHT INTO EARLY SATURDAY MORNING...BUT WILL BE HIGHLY
DEPENDENT ON CLOUD COVER AND PRECIPITATION COVERAGE (BOTH OF WHICH
CAN HAMPER MIXING STRONGER WINDS ALOFT TO THE SFC). AGAIN...WILL
NEED TO MONITOR THROUGH TODAY. WAVE HEIGHT MODELS HAVE BEEN OVERDONE
LATELY...THEREFORE SEAS FOR TODAY AND TONIGHT HAVE BEEN CAPPED AT
4 FT. EXPECT WAVES ON CHES BAY TO AVERAGE 2-3 FT DURING THIS SAME
TIME FRAME.
THE FRONT STALLS OVER SE VA/NE NC ON SATURDAY AND WILL FOCUS AFTN
THUNDERSTORM ACTIVITY OVER SRN WATERS...INCLUDING SRN CHES BAY AND
COASTAL WATERS SOUTH OF PARRAMORE ISLAND. THE STALLED FRONT
GRADUALLY PUSHES SOUTH OF THE WATERS FROM SUNDAY INTO NEXT WEEK...
HOWEVER PERIODS OF UNSETTLED WEATHER SHOULD STILL BE ANTICIPATED AS
MOISTURE AND ENERGY RIDE ALONG THIS BOUNDARY.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JDM
NEAR TERM...MAM
SHORT TERM...JDM/MAM
LONG TERM...MAS
AVIATION...BMD
MARINE...BMD
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
141 AM EDT FRI AUG 9 2013
.SYNOPSIS...
A SLOW MOVING FRONT CURRENTLY ACROSS THE EASTERN GREAT LAKES WILL
CONTINUE TO TRIGGER SHOWERS AND SOME THUNDERSTORMS OVERNIGHT AND
INTO FRIDAY. HIGH PRESSURE WILL THEN BUILD INTO THE AREA FOR THE
WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
SHOWERS AND THUNDERSTORMS HAVE DIMINISHED ACROSS THE REGION EARLY
THIS MORNING. HOWEVER...ANOTHER ROUND OF CONVECTION OVER
SOUTHWESTERN OHIO THAT`S TIED TO AN UPPER LEVEL SHORTWAVE WILL
CONTINUE TO MOVE EASTWARD OVER THE NEXT COUPLE OF HOURS. MANY OF
THE HI RES MODELS SUGGEST THAT ADDITIONAL SHOWERS AND
THUNDERSTORMS COULD BE REINVIGORATED AS THIS SHORTWAVE INTERACTS
WITH THE BOUNDARY THAT REMAINS JUST ALONG THE NORTHERN PERIPHERY
OF OUR FORECAST AREA. FOR NOW...DIMINISHED POPS FOR MUCH OF THE
AREA EAST OF THE OH/PA BORDER. THEN...WILL BRING IN LIKELY POPS INTO OUR
OHIO COUNTIES AS THIS AREA OF CONVECTION APPROACHES. TIMED THIS
BASED ON THE NAM AND HRRR WHICH LINED UP QUITE WELL WITH CURRENT
RADAR OBS.
CURRENT MESOSCALE ANALYSIS INDICATES PWAT VALUES NEAR 2 INCHES
OVER SOUTHERN OHIO EARLY THIS MORNING. WILL CONTINUE TO MONITOR
FOR ANY FLOODING CONCERNS ALTHOUGH EXPECT THIS TO REMAIN MORE OF A
LOCALIZED PROBLEM VS WIDESPREAD.
TEMPERATURES WILL REMAIN ELEVATED OVERNIGHT WITH PLENTY OF CLOUD
COVER PRESENT.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH MONDAY/...
THE CDFNT SHOULD SINK SLOWLY SWD ACRS THE AREA FRI. A SHRTWV AND
AREA OF DEEPER MOISTURE SHOULD ENHANCE SHWR CHCS AS WELL. MDL
PROGS SHOW LMTD INSTBY FRI SO SVR WEA THREAT IS LOW...HOWEVER
PWATS WL BE ELEVATED. DO NOT THINK THREAT FOR FLOODING IS WDSPRD
ENOUGH FOR A FLOOD WATCH ATTM...BUT DID MENTION PSBL LOCALIZED
FLOODING IN THE HWO. WL MONITOR. SHWR/TSTM CHCS SHOULD BE DCRG FM
N-S LT FRI THRU SAT AS THE CDFNT PUSHES S OUT OF THE AREA.
&&
.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
BEST CHANCE FOR SHOWERS IN THE EXTENDED WILL BE TUESDAY AS A
SECONDARY COLD FRONT CROSSES THE REGION. RAISED POPS TO CHANCE
WITH THIS SYSTEM AS MODELS AGREE ON MORE AVAILABLE MOISTURE.
OTHERWISE HIGH PRESSURE DOMINATES INTO LATE WEEK WITH TEMPERATURES
BELOW AVERAGE.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
A WIDE RANGE OF CIGS AND VSBY AT 06Z AS SHOWERS HAVE DIMINISHED.
LOW LEVEL MOISTURE AND WEAK FLOW WILL ALLOW MVFR TO IFR AT TIMES
UNTIL STRONGER SHORTWAVE APPROACHES FORM LOWER OHIO VALLEY TOWARD
DAYBREAK. WENT WITH ABOUT A 6 HOUR PERIOD OF IFR CIGS AND MVFR
IN SHOWERS AS SHORTWAVE MOVES AHEAD OF FRONT. EXPECT FROPA TOWARD
MID AFTERNOON WITH IMPROVING CONDITIONS TO VFR LATE TODAY AND
TONIGHT. WINDS WILL BECOME WEST THIS AFTERNOON BECOME NORTHWEST
THIS EVENING UNDER 10 KTS.
OUTLOOK.../SATURDAY THROUGH TUESDAY/... GENERAL VFR FOR THE WEEKEND
INTO MONDAY. A COLD FRONT WILL BRING POSSIBLE RESTRICTIONS
TUESDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
109 AM EDT FRI AUG 9 2013
.SYNOPSIS...
A SLOW MOVING FRONT CURRENTLY ACROSS THE EASTERN GREAT LAKES WILL
CONTINUE TO TRIGGER SHOWERS AND SOME THUNDERSTORMS OVERNIGHT AND
INTO FRIDAY. HIGH PRESSURE WILL THEN BUILD INTO THE AREA FOR THE
WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
SHOWERS AND THUNDERSTORMS HAVE DIMINISHED ACROSS THE REGION EARLY
THIS MORNING. HOWEVER...ANOTHER ROUND OF CONVECTION OVER
SOUTHWESTERN OHIO THAT`S TIED TO AN UPPER LEVEL SHORTWAVE WILL
CONTINUE TO MOVE EASTWARD OVER THE NEXT COUPLE OF HOURS. MANY OF
THE HI RES MODELS SUGGEST THAT ADDITIONAL SHOWERS AND
THUNDERSTORMS COULD BE REINVIGORATED AS THIS SHORTWAVE INTERACTS
WITH THE BOUNDARY THAT REMAINS JUST ALONG THE NORTHERN PERIPHERY
OF OUR FORECAST AREA. FOR NOW...DIMINISHED POPS FOR MUCH OF THE
AREA EAST OF THE OH/PA BORDER. THEN...WILL BRING IN LIKELY POPS INTO OUR
OHIO COUNTIES AS THIS AREA OF CONVECTION APPROACHES. TIMED THIS
BASED ON THE NAM AND HRRR WHICH LINED UP QUITE WELL WITH CURRENT
RADAR OBS.
CURRENT MESOSCALE ANALYSIS INDICATES PWAT VALUES NEAR 2 INCHES
OVER SOUTHERN OHIO EARLY THIS MORNING. WILL CONTINUE TO MONITOR
FOR ANY FLOODING CONCERNS ALTHOUGH EXPECT THIS TO REMAIN MORE OF A
LOCALIZED PROBLEM VS WIDESPREAD.
TEMPERATURES WILL REMAIN ELEVATED OVERNIGHT WITH PLENTY OF CLOUD
COVER PRESENT.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH MONDAY/...
THE CDFNT SHOULD SINK SLOWLY SWD ACRS THE AREA FRI. A SHRTWV AND
AREA OF DEEPER MOISTURE SHOULD ENHANCE SHWR CHCS AS WELL. MDL
PROGS SHOW LMTD INSTBY FRI SO SVR WEA THREAT IS LOW...HOWEVER
PWATS WL BE ELEVATED. DO NOT THINK THREAT FOR FLOODING IS WDSPRD
ENOUGH FOR A FLOOD WATCH ATTM...BUT DID MENTION PSBL LOCALIZED
FLOODING IN THE HWO. WL MONITOR. SHWR/TSTM CHCS SHOULD BE DCRG FM
N-S LT FRI THRU SAT AS THE CDFNT PUSHES S OUT OF THE AREA.
&&
.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
HIGH PRES WL SETTLE OVR THE GT LKS AND OH VLY RGN THRU MUCH OF THE
PD. THE ONLY EXCEPTION WL BE A WK CDFNT CROSSING THE AREA ON TUE.
MOISTURE IS LMTD WITH THIS FNT SO ONLY SLGT CHC POPS IN THE FCST.
TEMPS SHOULD AVG A LTL BLO SEASONAL AVGS.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
MORE RESTRICTIONS...MAINLY MVFR AND POSSIBLY IFR...CAN BE EXPECTED
TNGT IN THE FORM OF SHWRS...ST AND FOG GIVEN THE POOLING MSTR
ALNG...AND IN ADVN OF FRONTAL BNDRY.
OUTLOOK.../FRIDAY THROUGH TUESDAY/...
MORE SHWRS AND TSTMS ARE ANTICIPATED ALNG THE FRONT ON FRI. GENL
VFR WL DLVP THIS WEEKEND IN THE WAKE OF THE SWD PROGRESSING FRONT.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
459 AM EDT FRI AUG 9 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 458 AM EDT FRI AUG 9 2013
WV IMAGERY AND RUC ANALYSIS INDICATED SEVERAL WEAK SHORTWAVES
ROTATING AROUND A MID/UPPER LEVEL LOW OVER NRN ONTARIO. SCT/ISOLD
-SHRA PERSISTED MAINLY ACROSS THE SRN CWA SUPPORTED BY A WEAK
850-700 MB TROUGH AND UPPER LEVEL DIV WITH THE RIGHT ENTRANCE OF A
115 KNOT 300 MB JET TO THE NE OF LAKE SUPERIOR. A SHORTWAVE TROUGH
NW OF LAKE SUPERIOR ALSO SUPPORTED SOME ISOLD/SCT SHOWERS OVER NW
ONTARIO FROM SIOUX LOOKOUT TO DRYDEN.
TODAY...RADAR/SATELLITE TRENDS AND SHORT RANGE MODELS SUGGEST THAT
THE SHOWERS EARLY THIS MORNING WILL DEPART TO THE EAST OF THE CWA BY
AROUND 12Z. ALTHOUGH THE STRONGER 700-500 MB QVECTOR CONV ASSOCIATED
WITH THE NW ONTARIO SHRTWV WILL REMAIN NORTH OF UPPER MICHIGAN...THE
TAIL OF THIS FEATURE COMBINED WITH LOW LEVEL CONV ALONG THE LAKE
SUPERIOR BREEZE BOUNDARY AND MINIMAL MLCAPE VALUES TO NEAR 200 J/KG
IS EXPECTED TO GENERATE ISOLD -SHRA OVER INLAND PORTIONS OF
EAST CNTRL UPPER MICHIGAN. SOME -SHRA MAY ALSO BE POSSIBLE FARTHER
WEST FROM ESC-IMT ALONG A WEAK SFC TROUGH BUT CONFIDENCE WAS LOWER
SO PCPN WAS NOT MENTIONED AT THIS TIME. OTHERWISE...850 MB TEMPS
FROM 7C-9C WILL SUPPORT SCT/BKN CU DEVELOPMENT WITH CONTINUED BELOW
NORMAL HIGHS IN THE UPPER 60S AND LOWER 70S ARE EXPECTED.
TONIGHT...WITH THE LOSS OF DAYTIME HEATING AND HIGH PRES BUILDING
INTO THE REGION...CLEARING SKIES AND DIMINISHING WINDS WILL LEAD TO
FAVORABLE RADIATIONAL COOLING CONDITIONS OVERNIGHT. SO...KEPT FCST
MINS CLOSER TO THE LOWER END OF GUIDANCE...WITH READINGS INTO THE
LOWER TO MID 40S INLAND AND IN THE LOWER 50S ALONG THE GREAT LAKES.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 458 AM EDT FRI AUG 9 2013
OTHER THAN A PERIOD OF SCATTERED SHOWERS AND A FEW THUNDERSTORMS
SUNDAY AFTERNOON INTO MONDAY MORNING...A RATHER EXTENDED PERIOD OF
DRY WEATHER IS EXPECTED WITH SLIGHTLY BELOW NORMAL TEMPERATURES
THROUGH MUCH OF NEXT WEEK.
SATURDAY...DRY AIR WILL CONTINUE TO FILTER IN EARLY IN THE MORNING
AS A REINFORCING SFC HIGH AND WEAK RIDGING MOVE IN FROM THE WEST.
THERE HAS BEEN SOME HINT AT ISOLATED DIURNAL SHOWERS FORMING ACROSS
INTERIOR LOCATIONS BY BOTH THE NAM AND THE GFS OFF AND ON OVER THE
PAST TWO DAYS. INVESTIGATION OF FORECAST SOUNDINGS ACROSS THE CWA
SHOW WIDESPREAD CUMULUS DEVELOPMENT WITH 5 TO 7 KFT DEPTH. GIVEN
SHALLOW CLOUD DEPTH AND INSUFFICIENT MOISTURE ELSEWHERE IN THE
LAYER...ENTRAINMENT OF DRY AIR INTO THE CUMULUS FIELD SHOULD PREVENT
PRECIP DEVELOPMENT. IF ANY SHOWERS WERE TO FORM...THEY WOULD BE VERY
LIGHT AND LIKELY FOCUSED ON LAKE BREEZE CONVERGENCE ZONES ACROSS THE
INTERIOR CENTRAL AND EAST.
SATURDAY NIGHT THROUGH MONDAY NIGHT...WEAK SHORTWAVE RIDGING WILL BE
EXITING TO THE EAST SATURDAY EVENING AS A LARGE TROUGH AXIS ROTATES
SOUTHWARD ON THE BACKSIDE OF A DEEP EASTERN CANADIAN TROUGH. MODELS
HAVE BEEN PICKING UP ON A WEAK LEAD SHORTWAVE TROUGH TRACKING ACROSS
LAKE SUPERIOR SATURDAY NIGHT. DO NOT EXPECT MUCH MORE THAN SOME
INCREASED CLOUDINESS WITH THE WAVE. THE MAIN TROUGH AXIS THEN BEGINS
TO PUSH INTO THE AREA BY SUNDAY MORNING. THE 00Z NAM IS QUITE
AGGRESSIVE WITH BRINGING PRECIP INTO THE WESTERN CWA LATE SATURDAY
NIGHT AS IT APPEARS TO HAVE FALLEN VICTIM TO CONSIDERABLE
CONVECTIVE FEEDBACK FROM A POSSIBLE MCS ACROSS SOUTHERN MN. WILL
THEREFORE IGNORE THIS SOLUTION AND KEEP CONDITIONS DRY SATURDAY
NIGHT.
WITH MANY OF THE MODELS INDICATING DECENT MOISTURE TRANSPORT AND
ISENTROPIC LIFT CONFINED TO SOUTHERN MN AND CENTRAL/SOUTHERN WI...DO
NOT SEE THAT GREAT OF A POTENTIAL FOR ACTIVITY ACROSS THE CWA ON
SUNDAY. THE MAIN WILD CARD FOR THE DAY WILL BE HOW CLOUD DEBRIS FROM
ACTIVITY TO THE SOUTH LIMITS DAYTIME HEATING. WITH OVERALL MOISTURE
PROFILES ABOVE H7 QUITE DRY ACROSS UPPER MI...CLOUD COVER SHOULD
EASILY ERODE AND NOT INHIBIT OPTIMAL HEATING.
FOUND THE 00Z GFS QUITE REASONABLE WITH THE OVERALL SYNOPTIC
SET-UP...SO GAVE IT MORE WEIGHT IN THE FORECAST. A WEAK SECONDARY
SHORTWAVE WILL BE A FOCUS FOR AFTERNOON SHOWER AND STORM DEVELOPMENT
AS THE WAVE REACHES THE CENTRAL CWA BY MID AFTERNOON. WITH NORTHWEST
FLOW ALOFT...0 TO 6 KM BULK SHEAR WILL BE ON THE ORDER OF 35 KNOTS.
HOWEVER...SFC DEW POINTS ONLY IN THE MID 50S WILL LEAD TO POOR
INSTABILITY IN THE FORM OF MLCAPE OF 600 TO 900 J/KG. THIS SHOULD
LIMIT ANY ORGANIZED CONVECTION...AND OVERALL THUNDER COVERAGE FOR
THAT MATTER. HOWEVER...WITH A DRY SUBCLOUD LAYER AND DOWNDRAFT CAPE
OVER 1000 J/KG...THERE IS AN ELEVATED POTENTIAL FOR GUSTY WINDS
UNDER ANY STRONGER SHOWERS/STORMS. BEST CHANCE OF ANY CONVECTION
WILL BE SOUTH CENTRAL AND INTERIOR EAST IN THE AFTERNOON.
EXPECT ANY ACTIVITY TO DIMINISH WITH THE LOSS OF DAYTIME HEATING
SUNDAY EVENING. FORCING IS QUITE CONVOLUTED AT THIS POINT...WITH THE
POTENTIAL FOR MULTIPLE WEAK SHORTWAVES TO TRACK ACROSS THE CWA
THROUGH MONDAY. HAVE OPTED TO KEEP A GENERAL SLIGHT CHANCE OF
SHOWERS IN THE FORECAST FOR SUNDAY NIGHT AND MONDAY GIVEN
UNCERTAINTY OF LOCATIONS FOR BEST FORCING. OVERALL THINKING IS THAT
THE PERIOD WILL BE MOSTLY DRY WITH ONLY SEE ISOLATED SHOWERS FROM
TIME TO TIME.
MONDAY NIGHT THROUGH THURSDAY...MODEL AGREEMENT IS GOOD WITH
BRINGING IN MID-LEVEL RIDGING FROM THE WEST BY MID-WEEK. THERE
IS...HOWEVER...SOME DISAGREEMENT AT HOW QUICK THE TROUGH AXIS
COMPLETELY CLEARS THE CWA. THE GFS HAS SPED UP THE TROUGH OVER
RECENT RUNS...THE ECMWF HAS SLOWED THE TROUGH...AND THE GEM HAS HAS
WEAKENED THE TROUGH. NOT MUCH ONE CAN DO WITH THIS INFORMATION OTHER
THAN STICK WITH CONSENSUS DATA. WITH LIMITED MID-LEVEL
MOISTURE...WILL KEEP PRECIP OUT OF THE FORECAST FOR MONDAY NIGHT AND
TUESDAY. HIGH PRESSURE WILL THEN DOMINATE THE WEATHER THROUGH
THURSDAY. ANOTHER GOOD STRING OF NIGHTS WITH GOOD RADIATIONAL
COOLING APPEAR LIKELY...WITH TUESDAY NIGHT LEADING THE WAY AS THE
SFC HIGH SETTLES OVER THE WESTERN CWA. HAVE THUS LOWERED MIN TEMPS
SEVERAL DEGREES. THE GFS HINTS AT ISOLATED SHOWERS INTERIOR WEST ON
WEDNESDAY AFTERNOON...BUT A STOUT INVERSION WITH LIMITED RETURN
MOISTURE SHOULD PREVENT DEVELOPMENT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 133 AM EDT FRI AUG 9 2013
CONDITIONS ARE EXPECTED TO REMAIN VFR THROUGH THE TAF PERIOD. ON
FRI...ANOTHER TROUGH WILL MAKE ITS WAY INTO THE U.P. EXCEPT THE
AIRMASS IS MUCH DRIER THAN TODAY. EXPECTING THAT KCMX HAS THE ONLY
CHANCE OF SEEING THESE SHOWERS...AND WAS NOT CONFIDENT ENOUGH TO
PLACE IN THE TAF. WILL GET GUSTY WINDS AT ALL SITES AS WELL FRI
AFTERNOON.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 458 AM EDT FRI AUG 9 2013
WRLY WINDS ARE EXPECTED TO INCREASE INTO THE 15 TO 25 RANGE TODAY
BEHIND A TROUGH MOVING THROUGH LAKE SUPERIOR. HOWEVER...THE STRONGER
WINDS WILL BE RELATIVELY BRIEF SO MAX WAVE HEIGHTS ARE EXPECTED TO
REMAIN MAINLY IN THE 3 TO 5 FOOT RANGE. WINDS WILL VEER NW LATE
TODAY AND DIMINISH TONIGHT TO 5 TO 15 KNOTS AS HIGH PRES BUILDS INTO
THE REGION.
THE COMBINATION OF HIGH PRESSURE TRACKING SOUTHEASTWARD THROUGH WI
AND LOW PRESSURE DROPPING SOUTHWARD FROM NORTHWEST ONTARIO SATURDAY
WILL BRING W TO NW WINDS OF 10 TO 20 KNOTS ACROSS MUCH OF THE LAKE.
THE TROUGH WILL SLOWLY CROSS THE LAKE SUNDAY AFTERNOON THROUGH
MONDAY WITH WINDS UNDER 15 KNOTS. HIGH PRESSURE WILL THEN DOMINATE
THE REGION THROUGH THE MIDDLE OF NEXT WEEK AND PRODUCE WINDS UNDER
15 KNOTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KLUBER
AVIATION...07
MARINE...JLB/KLUBER
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
426 AM CDT FRI AUG 9 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 326 AM CDT FRI AUG 9 2013
A SURFACE RIDGE ORIENTED ALONG THE UPPER MINNESOTA RIVER VALLEY WAS
BUILDING ACROSS THE REGION...WITH MOSTLY CLEAR SKIES AND LIGHT WINDS
ACROSS THE REGION. AS OF THIS MORNING A FEW AREAS OF FOG HAD
DEVELOPED...BUT THESE WERE ISOLATED INSTANCES CONFINED MAINLY TO THE
LOW LYING AREAS. A LINGERING AREA OF SHOWERS STRADDLED THE MN/IA
BORDER LIKELY A RESULT OF WEAK H850 FGEN COUPLED WITH FAVORABLE JET
DYNAMICS IN THE RIGHT ENTRANCE REGION OF A H300 SPEED MAX. AT UPPER
LEVELS THE TWO MAIN FEATURES OF INTEREST WERE THE PERSISTENT CUTOFF
LOW ACROSS ONTARIO...AS WELL AS ANOTHER PV ANOMALY CENTERED OVER THE
REDWOOD FORESTS OF NORTHERN CALIFORNIA.
EVENTUALLY A SHORTWAVE WILL EJECT OFF THE CALIFORNIAN LOW AND BRING
A CHANCE FOR SHOWERS AND THUNDERSTORMS THIS WEEKEND. IN THE MEAN
TIME...NORTHWEST FLOW AND SURFACE RIDGING WILL KEEP THE REGION DRY
TODAY AND TONIGHT. COLD AIR ADVECTION TOGETHER WITH DIABATIC SURFACE
HEATING WILL QUICKLY MIX THE BOUNDARY LAYER TODAY ALLOWING NORTHWEST
WINDS OF 15 TO 20 MPH TO BECOME WIDESPREAD BY THIS AFTERNOON. ASIDE
FROM THESE BREEZY CONDITIONS...NO SIGNIFICANT SENSIBLE WEATHER TO
SPEAK OF WITH TEMPERATURES CONTINUING ON THE COOL SIDE AS AFTERNOON
HIGHS ONLY MANAGE MID TO UPPER 70S.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 326 AM CDT FRI AUG 9 2013
NOT MUCH CHANGE IN THE EXTENDED FROM WHAT WE HAVE BEEN SEEING THE
PAST COUPLE DAYS. ITS FAIRLY OBVIOUS WHEN LOOKING AT THE 240-HR RUN
TOTAL QPF OFF THE GFS/ECMWF THAT THE SYNOPTIC FRONTAL BOUNDARY
STRETCHES EASTWARD FROM OK/KS TO THE MID ATLANTIC STATES WITH AN
ANOMALOUSLY DEEP TROUGH IN THE EAST. THIS IS WHERE THE MOST RAIN
IS EXPECTED TO FALL OVER THE NEXT 7-10 DAYS. THE STRONG RIDGING
OVER THE ATLANTIC OCEAN IS FORCING THE PERSISTENT TROUGHING IN THE
EASTERN CONUS AND RIDGING UPSTREAM IN THE WEST. MN/WI REMAINS
UNDER THE INFLUENCE OF COOLER CYCLONIC FLOW AND WE EXPECT THIS TO
CONTINUE FOR AT LEAST THE NEXT SEVERAL DAYS. THE NEXT CHANCE FOR
SHOWERS AND STORMS COMES ON SUNDAY WHEN A WAVE EMBEDDED IN
NORTHWEST FLOW PASSES ACROSS THE AREA. AS IS TYPICAL...THE MODEL
GUIDANCE IS STARTING TO BECOME MORE ALIKE IN THERE REPRESENTATION
AND TIMING OF THIS FEATURE. DP/DT OF THE NAM/GFS/ECMWF ALSO SHOWS
LESS AMPLIFICATION WITH TIME AND THEREFORE FASTER SOLUTIONS. EVEN
WITH THE SHALLOWER AND FASTER SOLUTIONS...WE HAVE NOT REALLY SEEN
A SIGNIFICANT DROP IN THE MODEL QPF. THE 09.00/06Z RUNS ARE STILL
GENERATING BETWEEN 0.50-1.50" OF CONVECTIVE PRECIP. THE SPECIFIC
PLACEMENT OF THE BULLS EYE IS STILL NOT CERTAIN...BUT THERE HAS
BEEN A GRADUAL SHIFT SOUTH. THIS MAKES SENSE BECAUSE IT`S WHERE
THE GREATEAST POOL OF CAPE IS LOCATED /IN THE STATES JUST TO OUR
SOUTH/. LOW CONFIDENCE IN THE QPF/POP FORECAST SUNDAY...LOOKS
BETTER IN SOUTHERN MN...BUT BIG QUESTION MARKS STILL FOR PLACES
LIKE ST. CLOUD...TWIN CITIES...AND EAU CLAIRE.
THE GFS/ECMWF/GEFS ARE IN GOOD AGREEMENT WITH THE POSITION OF THE
MASS FIELDS THROUGH 100-120 HOURS. HOWEVER...BY NEXT
WEDNESDAY...THE OPERATIONAL GFS BECOMES A LITTLE MORE PROGRESSIVE
IN MOVING THE WEST COAST RIDING CLOSER TO MN/WI. THIS WOULD
SUGGEST WARMER TEMPS FOR THE SECOND HALF OF NEXT WEEK /MORE LOWER
80S AT LEAST/. THE ECMWF HANGS THE RIDGE BACK AND THE GEFS IS ALSO
A BIT FARTHER WEST THAN ITS OPERATIONAL COUNTERPART. HIGH
CONFIDENCE IN THE TEMP FORECAST OVER THE NEXT 7 DAYS. THERE IS VERY
LITTLE SPREAD IN THE GUIDANCE AND MOST DAYS THE RANGE IN HIGH
TEMPS IS 3-5 DEGREES /A BIT MORE FOR LOW TEMPS/. THE BIGGEST TEMP
SPREAD COMES ON SUNDAY WITH THE WARM ADVECTION...THEN CLOUD COVER
AND RAIN...SO NO SURPRISE THERE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1241 AM CDT FRI AUG 9 2013
SKIES WILL CLEAR OVERNIGHT WHICH WILL SET THE STAGE FOR FOG AT A
FEW SUSCEPTIBLE LOCATIONS...MAINLY KRWF...KSTC...AND KEAU. HIRES
MODELS SUCH AS THE HRRR AND HOPWRF CONTINUE TO DROP VISIBILITIES
LESS THAN A HALF MILE...SUPPORTING THE INCLUSION OF FOG AT THOSE
SITES. ON FRIDAY NORTHWEST WINDS WILL INCREASE AND COULD GUST TO
NEAR 20KTS DURING THE AFTERNOON.
KMSP...
LIGHT WINDS SHOULD GO CALM OVERNIGHT. THE FOG POTENTIAL AT MSP IS
TOO LOW TO INCLUDE MENTION IN THE TAFS. ON FRIDAY EXPECT VFR
CONDITIONS WITH NORTHWEST WINDS GUSTING TO NEAR 20KTS AT TIMES.
THE GUSTS WILL TAPER OFF AFTER SUNSET.
/OUTLOOK FOR KMSP/
SAT...VFR. WINDS NW AT 05KTS.
SUN...VFR WITH -TSRA POSSIBLE. WINDS S AT 05KTS.
MON...VFR. WINDS N AT 05KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...JRB
LONG TERM...CLF
AVIATION...JRB
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1249 AM CDT FRI AUG 9 2013
.UPDATED FOR 06Z AVIATION DISCUSSION...
ISSUED AT 1241 AM CDT FRI AUG 9 2013
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 1225 PM CDT THU AUG 8 2013
SHOWER ACTIVITY WILL CONTINUE TO WANE INTO THE EVENING HOURS AS
THE WEAK IMPULSE SLIDES EAST OF THE AREA. MID LEVEL CLOUDS SCATTER
OUT THIS EVENING...WITH TEMPERATURES COOLING INTO THE UPPER 40S TO
UPPER 50S RANGE. DRY CONDITIONS ARE EXPECTED FOR FRIDAY AS SURFACE
HIGH PRESSURE ARRIVES AND DRYING OF THE MID LEVELS YIELDS MOSTLY
SUNNY SKIES. 75 TO 80 DEGREE HIGHS WITH A FEW SITES ALONG THE MN
RIVER VALLEY POTENTIALLY REACHING INTO THE LOW 80S STILL LOOKS
REASONABLE.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 232 PM CDT THU AUG 8 2013
THE MAIN CHG FOR THE EXTENDED PERIOD IS WHETHER SAT/SUNDAY/S WX
SYSTEM WILL TRACK FASTER...HOLD BACK...OR/AND BE A BIT FURTHER TO
THE SOUTH.
THE SHRTWV IN QUESTION IS VERY WEAK AND DISORGANIZED ACROSS THE
SOUTHWESTERN U.S. EARLY THIS AFTN. THE STRONG UPPER LOW ACROSS
SOUTHERN CANADA WILL SLOWLY MODIFY AND MOVE OFF TO THE EAST/NE
OVER THE NEXT TWO DAYS. THE MEAN FLOW ACROSS THE UPPER MIDWEST
WILL BE CAUGHT IN BETWEEN THIS DEPARTING UPPER LOW...AND THE
SHRTWV MOVING NORTH...THEN EVENTUALLY E-SE ACROSS THE NORTHERN
PLAINS/UPPER MIDWEST OVER THE WEEKEND. SEVERAL MODEL RUNS AGO THIS
SYSTEM WAS STRONGER AND SLOWLY ACROSS THE DAKOTAS...AND NOT
AFFECTING MN/WI UNTIL SUNDAY/SUNDAY NIGHT. THEREFORE...THIS
WEEKENDS FORECAST IS HIGHLY BASED ON THE MOVEMENT OF THIS SHRTWV
AND THE STRENGTH OF IT ONCE IT MOVES ACROSS THE UPPER MIDWEST.
ALTHOUGH THE SFC LOW AND ASSOCIATED SFC BOUNDARY ARE FURTHER TO
THE SOUTH ACROSS THE UPPER MIDWEST/NORTHERN PLAINS AS IN THE
PREVIOUS MODEL RUN/S...THIS FEATURE WILL LIKELY GO THROUGH A PERIOD
OF CHGS ON STRENGTH AND POSITION. DUE TO MOST OF THE RICH TROPICAL
MOISTURE HOLDING ACROSS THE CENTRAL PLAINS/MID MISSISSIPPI VALLEY
REGION...OUR SYSTEM WILL LIKELY NOT BE A WET IN TERMS OF RAINFALL
AMTS.
NOT TOO MANY CHGS PAST SUNDAY WITH THE CONTINUED W-NW FLOW ALOFT
AS THE MEAN TROUGH HOLDS ACROSS EASTERN NORTH AMERICA...WITH A
WEAK RIDGE ACROSS THE ROCKIES. AS WITH YESTERDAY/S DISCUSSION ON
THE RETROGRADING OF THE UPPER RIDGE ACROSS THE SOUTHERN
PLAINS...AND INTO THE DESERT SW...THIS STILL REMAINS PLAUSIBLE
BASED ON THE LATEST UPPER AIR FLOW IN THE NEXT 7 TO 10 DAYS. OUR
WEATHER WILL REMAIN SOMEWHAT COOLER THAN NORMAL...WITH HUMIDITY
LEVELS QUITE DRY FOR MID AUGUST.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1241 AM CDT FRI AUG 9 2013
SKIES WILL CLEAR OVERNIGHT WHICH WILL SET THE STAGE FOR FOG AT A
FEW SUSCEPTIBLE LOCATIONS...MAINLY KRWF...KSTC...AND KEAU. HIRES
MODELS SUCH AS THE HRRR AND HOPWRF CONTINUE TO DROP VISIBILITIES
LESS THAN A HALF MILE...SUPPORTING THE INCLUSION OF FOG AT THOSE
SITES. ON FRIDAY NORTHWEST WINDS WILL INCREASE AND COULD GUST TO
NEAR 20KTS DURING THE AFTERNOON.
KMSP...
LIGHT WINDS SHOULD GO CALM OVERNIGHT. THE FOG POTENTIAL AT MSP IS
TOO LOW TO INCLUDE MENTION IN THE TAFS. ON FRIDAY EXPECT VFR
CONDITIONS WITH NORTHWEST WINDS GUSTING TO NEAR 20KTS AT TIMES.
THE GUSTS WILL TAPER OFF AFTER SUNSET.
/OUTLOOK FOR KMSP/
SAT...VFR. WINDS NW AT 05KTS.
SUN...VFR WITH -TSRA POSSIBLE. WINDS S AT 05KTS.
MON...VFR. WINDS N AT 05KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...LS
LONG TERM...JLT
AVIATION...JRB
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1234 AM CDT Fri Aug 9 2013
.UPDATE...
Issued at 929 PM CDT THU AUG 8 2013
Heavy rain threat has ended for the far southern two tier of counties
for the rest of tonight as well as Friday. Convection has sprouted
further south than the previous two nights and expect it to spread
across OK/AR tonight with a gradual shift northeast into southern
KS/MO late tonight through Friday morning. Latest NAM/RAP/local WRF
continue to show little if any QPF over the CWA tonight. HRRR has
been the best predictor of the 12-15hr period for the past several
days/nights and it too keeps the CWA basically dry. Will roll back
PoPs and go with isolated light showers overnight except increase
them over the CWA as the northern edge of the precipitation shield of
the convective complex spreads northeast.
Have also adjusted PoPs a bit on Friday to reflect the lower
confidence on rain chances. The southern CWA still retains the
highest PoPs but heavy rainfall not likely.
UPDATE Issued at 730 PM CDT THU AUG 8 2013
Relying on radar trends and HRRR which has proven to have a better
track record over the next 12 hours. Heavy rain looks like it will
shift into southern MO and out of the CWA. Will wait to see what the
00z NAM looks like before pulling the plug on the Flash Flood Watch.
For now will lower PoPs across the board with best bet for measurable
rain over the far southern counties. Sprinkles/light showers possible
through mid evening over eastern KS/west central and northwest MO.
&&
.SHORT TERM...(This Evening through Friday)
Issued at 300 PM CDT THU AUG 8 2013
Tonight/Friday: High uncertainty exists within forecast the next 24
hours. Current model initialization have done a poor job with
short-term trends, lending to decreased confidence in solutions for
tonight into Friday. Well-defined MCV per visible satellite and
radar trends continues to spin over central Kansas. Over the past
hour, an increasing trend of echoes has been noted over portions of
Kansas, Missouri, and southern Nebraska. The coverage, persistence,
and intensity of this activity remain quite uncertain. Do not
anticipate this activity to become heavy and should only persist for
a few more hours, otherwise could have a moderate effect to going
forecast. Dry air from H7-H85 has prevented an eastward expanse to
precipitation since this morning, and models show this layer only
gradually moistening through the overnight hours. Current surface
analysis shows frontal boundary sagging southward to near the
Oklahoma-Kansas border, with profiler data showing the H85 front
just south of the forecast area. Virtually every model solution
suggests a southward shift of the heavy precipitation corridor for
tonight/Friday, and this along with current surface/profiler data,
is compelling enough to subsequently shift heavy rain axis to the
south by at least 50 miles. Current forecast places up to one inch
of rainfall in the far southern sections of the CWA, with decreasing
amounts with northward extent. Therefore, will cancel flash flood
watch for areas along Interstate 70, and continue the southern two
rows of counties as a conditional threat if a heavy rain corridor
can make it this far north. Upper disturbance over Colorado will
make its way eastward into the Central Plains tonight, but will also
begin to weaken some with time. Still, with some increase in ascent
and close proximity to surface/elevated boundaries, cannot rule out
southern sections of the forecast area receiving moderate to
occasionally heavy rainfall late tonight into Friday. Decreasing
probabilities of rain are expected after noon Friday.
.LONG TERM...(Friday Night through Thursday)
Issued at 300 PM CDT THU AUG 8 2013
Precipitation chances will focus primarily south of the forecast
area during much of the weekend as flow becomes more zonal and the
primary focus for precipitation becomes a stationary boundary near
the MO/AR border. Ongoing precipitation Friday could linger into
Friday night as the boundary sinks back to the south; afterward,
just a few stray showers and storms possibly brushing far southern
portions of the CWA will bring the only chance of precipitation
through Sunday afternoon. Temperatures this weekend will recover to
near normal with a few breaks of sunshine Saturday and surface winds
returning to the south on Sunday.
As upper-level low pressure deepens across northern Canada and the
pattern transitions into northwest flow, most models bring a weak
shortwave trough into northwest Missouri on Sunday night into early
Monday. This feature could bring in a quick shot of precipitation
and a weak frontal boundary as it pushes east southeast; however,
forcing looks fairly weak and should keep rainfall amounts low. The
boundary may again become stationary across southern Missouri and
allow rainfall chances to linger into Tuesday, but will focus
generally south of the CWA. Then for the remainder of the forecast
period, generally dry conditions are expected with the boundary
remaining south of the region and the trough in the east keeping
most northern disturbances separate from the best moisture. High
temperatures will also be a few degrees below normal next week, as a
result of the boundary remaining to the south and northwest flow
helping a bit cooler air filter down from the northern Plains.
&&
.AVIATION...(For the 06Z TAFS through 06Z Friday Night)
Issued at 1229 PM CDT THU AUG 8 2013
VFR conditions will continue through the TAF period with mid level
clouds between 6-10kft. A complex of thunderstorms across northern
Oklahoma will spread northeast into southeastern Kansas overnight
into tomorrow morning. These showers may spread as far north as MCI
and MKC by tomorrow afternoon however model consensus keeps
precipitation south of the terminals. However, did keep VCSH at MKC
and MCI tomorrow afternoon. Winds during the TAF period will be light
out of the northeast.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
UPDATE...MJ
SHORT TERM...Blair
LONG TERM...Laflin
AVIATION...73
AREA FORECAST DISCUSSION
NWS HASTINGS NE
219 AM CDT FRI AUG 9 2013
.UPDATE...
ISSUED AT 133 AM CDT FRI AUG 9 2013
UPDATED THE FORECAST TO INCLUDE FOG OVERNIGHT AND EARLY SATURDAY
MORNING AS THE HRRR HAS INDICATED MORE OF A CHANCE OF
FOG...ESPECIALLY ON THE NEBRASKA SIDE...WHERE THE SKY COVER HAS
CLEARED.
UPDATE ISSUED AT 942 PM CDT THU AUG 8 2013
REMOVED THUNDERSTORMS FROM THE FORECAST TONIGHT BASED ON MODEL
INSTABILITY...AS WELL AS CURRENT RADAR AND SATELLITE TRENDS. ALSO
DECREASED POPS SIGNIFICANTLY ACROSS THE OUTLOOK AREA TONIGHT
THROUGH MID MORNING FRIDAY.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 427 PM CDT THU AUG 8 2013
BEEN LITTLE CHANGE IN THE OVERALL PATTERN ACROSS THE REGION...WITH
UPPER AIR AND SATELLITE DATA CONTINUING TO SHOW ZONAL FLOW IN THE
UPPER LEVELS...SET UP BETWEEN BROAD TROUGHING JUST TO THE EAST AND A
RIDGE AXIS IN PLACE OVER PORTIONS OF THE ROCKIES. BETWEEN THE
PASSAGE OF ONE UPPER LEVEL DISTURBANCE LAST NIGHT/EARLY THIS MORNING
AND ANOTHER APPROACHING FROM THE WEST...IT HAS BEEN A CLOUDY/DREARY
AND COOLER DAY ACROSS THE CWA. TEMPS HAVE BEEN HANGING OUT IN THE
70S...AND WITH SURFACE HIGH REMAINING IN PLACE ACROSS THE
AREA...WINDS CONTINUE TO BE ON THE LIGHT/VARIABLE SIDE.
LOOKING AT THE REST OF THIS AFTERNOON AND INTO THIS
EVENING/TONIGHT...THE MAIN STORY WILL CONTINUE TO LIE WITH
PRECIPITATION CHANCES. RECENT RADAR TRENDS SHOWING AN INCREASE IN
RETURNS ACROSS THE CWA ASSOCIATED WITH THAT NEXT MID/UPPER LEVEL
DISTURBANCE...WITH MODELS IN DECENT AGREEMENT WITH ITS CONTINUED
EASTWARD PASSAGE THROUGH THE REGION. INSTABILITY IS MEAGER...AND
SHEAR/LAPSE RATES ARE LOW...SO WHILE A FEW THUNDERSTORMS WILL BE
POSSIBLE...NOT EXPECTING IT TO BE WIDESPREAD AND WILL KEEP MENTION
OF SHOWERS WITH ISOLATED THUNDER.
WITH LITTLE CHANGE IN THE PATTERN THROUGH THE SHORT TERM
PERIOD...PRECIPITATION CHANCES WILL BE PRESENT AGAIN TOMORROW...WITH
MODELS SHOWING YET ANOTHER DISTURBANCE SET TO MOVE THROUGH THE
REGION. THE BETTER FOCUS LOOKS TO BE MOSTLY TO THE SOUTH...CLOSER
TO THE MAIN SFC FRONT...BUT COULD STILL AFFECT AT LEAST PORTIONS OF
THE CWA...SO KEPT POPS GOING WITH BETTER CHANCES IN OUR NC KS
COUNTIES. SURFACE HIGH PRESSURE REMAINS IN PLACE...KEEPING THE
LIGHT/VARIABLE WINDS AROUND.
AS FAR AS TEMPERATURES GO...OVERNIGHT LOWS TONIGHT EXPECTED TO AGAIN
BOTTOM OUT IN THE 60S...WITH HIGH TEMPERATURES TOMORROW FORECAST IN
THE LOWER 80S...WITH NOT AS MUCH CLOUD COVER EXPECTED AS TODAY.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 427 PM CDT THU AUG 8 2013
FOR THE MOST PART...THIS 6-DAY PERIOD REFLECTS LITTLE CHANGE FROM
THE PREVIOUS FORECAST...WITH MULTIPLE...LOW-CONFIDENCE RAIN
CHANCES IN THE SAT EVENING-THURSDAY TIME FRAME...BUT NOTHING THAT
STANDS OUT AS A HEIGHTENED CHANCE OF A WIDESPREAD SOAKER...LET
ALONE A HEIGHTENED RISK OF SEVERE WEATHER. IN OTHER WORDS...THE
PRESENCE OF SHOWER/THUNDERSTORM WORDING IN ALMOST EVERY FORECAST
PERIOD SHOULD NOT BE TAKEN AS A SIGN THAT ALL PLACES WILL SEE
NOTABLE RAINFALL DURING THE NEXT WEEK...ALTHOUGH LOCALIZED SPOTS
PROBABLY WILL SEE AT LEAST 1-2 INCHES. AS FOR CHANGES THAT WERE
MADE TO PREVIOUS FORECAST...BOTH LOW AND HIGH TEMPS WERE NUDGED UP
A BIT FROM FRI NIGHT-SUNDAY...AND SLIGHT POPS WERE ADDED FOR
FRIDAY EVENING. EVEN SO...HIGH TEMPS WILL CONTINUE TO AVERAGE AT
LEAST SLIGHTLY BELOW NORMAL MOST EVERY DAY...PROLONGING AN
INCREASINGLY IMPRESSIVE LACK OF HIGHER-END SUMMER HEAT THAT HAS
BEEN ONGOING SINCE JULY 23RD.
STARTING OUT FRIDAY EVENING/NIGHT...THE LARGE-SCALE SYNOPTIC
PICTURE ALOFT FEATURES FAIRLY WEAK QUASI-ZONAL FLOW PERSISTING
OVER THE REGION...AS THE CENTRAL PLAINS REMAINS IN BETWEEN A BROAD
EAST-WEST RIDGE CENTERED OVER THE SOUTHERN STATES...AND A LARGE
SCALE TROUGH EXTENDING FROM SOUTHEAST CANADA INTO THE GREAT
LAKES/NORTHEAST STATES...WHILE WELL OFF TO THE WEST A SLOW-MOVING
CLOSED LOW PERSISTS NEAR THE CA/OR COAST. AT THE SURFACE...BROAD
HIGH PRESSURE CENTERED JUST EAST OF THE AREA WILL RESULT IN VERY
LIGHT PREVAILING EASTERLY/SOUTHERLY LOW. STRONGLY CONSIDERED
LEAVING THE ENTIRE 12-HOUR PERIOD VOID OF RAIN MENTION...BUT
ENOUGH MODELS SUCH AS THE NAM/GFS AND ALSO REFLECTIVITY PER THE
12Z 4K WRF-NMM...SUGGESTED THAT IT MIGHT BE BEST TO INTRODUCE A
SLIGHT CHANCE OF SHOWERS/ISOLATED THUNDERSTORMS TO ALL AREAS
DURING THE EVENING. ALTHOUGH CONFIDENCE IS CERTAINLY QUITE LOW ON
PLACEMENT...AND THUS THE BROAD-BRUSHED SLIGHT POPS ALL AREAS...SUBTLE
FORCING FROM A MID LEVEL DISTURBANCE GENERALLY TRACKING ACROSS THE
SOUTHERN CWA...AND POSSIBLY ALSO LOWER-LEVEL CONVERGENCE ALONG A
WEAK SURFACE BOUNDARY MAINLY WITHIN THE NORTHERN 1/2 OF NEBRASKA
COULD SPARK A FEW AREAS OF CONVECTION. SOME OF THIS ACTIVITY COULD
SIMPLY BE A CONTINUATION OF LATE-AFTERNOON ACTIVITY. AT ANY
RATE...WITH WEAK DEEP LAYER SHEAR AND 0-1KM MLCAPE PER THE NAM
QUICKLY DROPPING WELL UNDER 500 J/KG IN MOST AREAS POST-
00Z...CERTAINLY NOT FORESEEING A SEVERE THREAT. POST-
MIDNIGHT...KEPT THE FORECAST DRY AT LEAST FOR NOW...AS FORCING
APPEARS MINIMAL AND THE NOSE OF THE 850 MILLIBAR LOW LEVEL JET
AIMS WELL TO THE NORTH. NUDGED UP LOW TEMPS 1-2 DEGREES MOST
AREAS PER LATEST MET/MAV GUIDANCE TRENDS...WITH NEARLY ALL AREAS
LOW 60S.
SATURDAY/SATURDAY NIGHT...THE LARGE SCALE SCENE ALOFT CHANGES
LITTLE...AS DOMINANT RIDGING REMAINS TO THE SOUTH...AND PREVAILING
TROUGHING REMAINS ACROSS THE FAR WEST AND NORTHEAST CONUS. THERE
WILL CONTINUE TO BE LOW-AMPLITUDE SHORTWAVE TROUGHS WORKING
THROUGH THE LOCAL QUASI-ZONAL FLOW HOWEVER...ALTHOUGH EVEN AT THIS
RANGE MODELS ARE IN DISAGREEMENT ON THE MOST FAVORED
TRACK...ALTHOUGH THE 12Z ECMWF NOW SHOWS A FAIRLY POTENT SMALL
SHORTWAVE/POSSIBLY MCV FEATURE DRIFTING THROUGH THE NORTHERN 1/2
OF NEBRASKA. AT LEAST FOR NOW...HAVE LEFT THE DAYTIME PERIOD VOID
OF RAIN MENTION TO STAY CONSISTENT WITH LAST SEVERAL FORECAST
ISSUANCES...BUT THIS IS NOT YET A GUARANTEE TO REMAIN SO. THAT
BEING SAID...BEST CHANCES FOR AFTERNOON CONVECTION SHOULD REMAIN
AT LEAST SLIGHTLY NORTH AND/OR WEST OF THE CWA. THE LATEST NAM
SOUNDINGS SHOW DECENT 0-1KM MLCAPE OF 1000+ J/KG DEVELOPING OVER
THE AREA DURING THE AFTERNOON...BUT ALSO WITH A WEAK CAP HOLDING
THINGS AT BAY. AT THE SURFACE...ALTHOUGH BY NO MEANS
WINDY...SATURDAY MAY HAVE ONE OF THE STEADIER BREEZES OF THE
ENTIRE FORECAST...GENERALLY 10-15 MPH FROM THE SOUTH DURING THE
AFTERNOON. ASSUMING DAYTIME CONVECTION HOLDS AT BAY...THE LOW
LEVEL TEMP FIELD SUPPORTS A 1-3 DEGREE INCREASE IN HIGH TEMPS
VERSUS PREVIOUS FORECAST...AND NOW HAVE MOST AREAS 83-85...BUT
THIS IS STILL NOT AS WARM AS THE LATEST NAM/MET WOULD SUGGEST. FOR
SATURDAY NIGHT...A BIT BETTER LOW LEVEL THETA-E ADVECTION SIGNAL
SUGGESTS THAT ESPECIALLY THE NORTHERN/WESTERN CWA COULD GET IN ON
SOME STORMS. DUE TO OBVIOUS UNCERTAINTY AT THIS TIME RANGE...OPTED
TO GO AHEAD AND LEAVE PREVIOUS FORECAST ESSENTIALLY UNCHANGED FOR
NOW...WITH SLIGHT POPS ONLY CONFINED TO AREAS NORTH OF I-80. AGAIN
THINKING LITTLE IF ANY SEVERE THREAT.
SUNDAY DAYTIME THROUGH MONDAY NIGHT...20-40 POPS ARE IN PLACE ACROSS
THE ENTIRE CWA THIS ENTIRE TIME...WITH THE MAIN CONCENTRATION OF
HIGHEST 40 POPS FOCUSED ON SUNDAY NIGHT...AT LEAST FOR NOW.
AGAIN...THE MID/UPPER AIR PATTERN REMAINS NOTABLY
CONSISTENT...WITH THE CENTRAL PLAINS UNDER NEAR-ZONAL TO SLIGHTLY-
NORTHWESTERLY FLOW...BETWEEN A SOUTHERN CONUS RIDGE AND NORTHEAST
CONUS TROUGH. AS VARIOUS SMALLER-SCALE WAVES WORK THROUGH THE
FLOW...THERE COULD BE VARIOUS ROUNDS OF THUNDERSTORMS...BUT TO SAY
CONFIDENCE IS LOW IN THE DETAILS IS AN UNDERSTATEMENT. ITS
POSSIBLE THAT SUNDAY AFTERNOON INTO SUNDAY EVENING COULD FEATURE A
MARGINAL SEVERE/HEAVY RAIN THREAT...BUT WITH DEEP LAYER SHEAR
STRUGGLING TO REACH 30 KNOTS AND THIS BEING 3+ DAYS AWAY...IT
STILL SEEMS A BIT EARLY TO EVEN PINPOINT THIS TIME FRAME IN THE
HAZARDOUS WEATHER OUTLOOK. BUMPED UP HIGH TEMPS SUNDAY 1-2 MOST
AREAS...MAINLY MID 80S IN NEB AND UPPER 80S IN KS...WITH MONDAY
GENERALLY LOW 80S AND MID 80S IN THESE SAME AREAS...RESPECTIVELY.
TUESDAY THROUGH THURSDAY...20-30 POPS CONTINUE TO BLANKET THE
ENTIRE CWA THIS ENTIRE TIME...AND OBVIOUSLY LATER SHIFTS WILL HAVE
TO GRADUALLY REFINE THESE VERY MURKY RAIN CHANCES. ON THE LARGE-
SCALE...THE LATEST ECMWF/GFS ARE IN PRETTY GOOD AGREEMENT SHOWING
THE FLOW ALOFT OVER THE CENTRAL PLAINS TRANSITIONING FROM MORE
ZONAL TO MORE TRUE-NORTHWESTERLY...AS THE RIDGE STRENGTHENS AND
BUILDS NORTH OVER THE ROCKIES. THIS CONTINUES TO PLACE THE LOCAL
REGION IN THE PATH OF PERIODIC LOW AMPLITUDE SHORTWAVE
TROUGHS...THAT COULD KICK OFF CONVECTION OVERHEAD...OR ALLOW HIGH
PLAINS CONVECTION TO SURVIVE EASTWARD INTO THE AREA. SO MANY
DETAILS TO SORT OUT AS THIS TIME FRAME NEARS. TEMP-WISE...MADE
VERY LITTLE CHANGE TO PREVIOUS FORECAST...WITH HIGHS GENERALLY
LOW-MID 80S AND LOWS MID 60S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 133 AM CDT FRI AUG 9 2013
REDUCED VISIBILITY WILL BE THE BIGGEST ISSUE FOR THE FORECAST
OVERNIGHT INTO FRIDAY MORNING. SOME MODELS INDICATE THAT WE COULD
TANK DOWN TO LIFR...BUT STAYING A LITTLE MORE CONSERVATIVE DOWN TO
IFR FOR A SHORT TIME BEFORE IMPROVEMENT OCCURS. SOME ISOLATED
SHOWERS COULD OCCUR FOR FRIDAY AND FRIDAY EVENING...BUT CHANCES
ARE LOW ENOUGH TO NOT INCLUDE IN THE FORECAST FOR NOW.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...HEINLEIN
SHORT TERM...ADO
LONG TERM...PFANNKUCH
AVIATION...HEINLEIN
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1145 PM CDT THU AUG 8 2013
.AVIATION...06Z TAFS FOR KOFK...KLNK AND KOMA.
BROKEN MID LEVEL CLOUDS WILL GRADUALLY SCATTER THROUGH 18Z...WITH
PERIODS OF CLEAR SKIES ALLOWING MVFR FOG TO FORM AROUND 12Z. VSBYS
COULD BRIEFLY DROP TO 2SM AT KOFK. THEN VFR CONDITIONS ARE
FORECAST FROM MID MORNING ON AS NORTH TO NORTHEAST WINDS AND
SCATTERED MID AND HIGH CLOUDS ARE EXPECTED.
DERGAN
&&
.PREV DISCUSSION... /ISSUED 342 PM CDT THU AUG 8 2013/
DISCUSSION...
MAIN SHORT TERM CONCERN IS POPS THROUGH TONIGHT AS SCATTERED
SHOWERS CONTINUE TO DRIFT EAST ACROSS THE CWA.
LATEST WATER VAPOR IMAGERY AND LATEST RAP 500MB ANALYSIS SHOW A
LARGE UPPER LOW OVER ONTARIO WITH A RIDGE EXTENDING FROM THE FOUR
CORNERS REGION INTO BRITISH COLUMBIA. IN BETWEEN THIS...A WEAK
SHORTWAVE EXTENDS FROM EASTERN NEBRASKA INTO NORTHEAST KANSAS WITH
ANOTHER CIRCULATION IN SOUTH CENTRAL COLORADO.
THE SHORTWAVE ENERGY OVER THE REGION CONTINUES TO SUPPORT AN AREA
OF WIDELY SCATTERED SHOWERS OVER THE FORECAST AREA. THE LATEST RAP
SEEMS TO HAVE A GOOD HANDLE...ALBEIT A BIT OVERDONE ON QPF...AND
HAVE FOLLOWED MORE CLOSELY TO ITS TRENDS. UPPER LEVEL SUPPORT WILL
MOVE OUT OF THE AREA EARLY THIS EVENING SO HAVE ONLY CARRIED A
MENTION OF PCPN THROUGH THIS TIME. DID CONTINUE A MENTION OF SMALL
POPS IN THE FAR SOUTHEAST AFTER 06Z WITH SOME WEAK UPPER LEVEL
SUPPORT REMAINING INTO THE MORNING.
FRIDAY CONTINUES TO LOOK MOSTLY DRY BUT DID KEEP A SMALL POP IN
FOR THE SOUTH WITH SOME WEAK UPPER LEVEL SUPPORT IN THE AREA.
WITH MID/UPPER LEVEL FLOW OUT OF THE NORTHWEST THROUGH THE
WEEKEND...AND INCREASING WAA REGIME...WILL KEEP SOME SCATTERED
POPS ACROSS THE AREA...MAINLY IN THE NORTH. A STRONGER SHORTWAVE
WILL SLIDE ACROSS SOUTH DAKOTA THROUGH THE NORTHWEST FLOW
SATURDAY...SO BEST CHANCES WILL BE IN THE NORTH...ALTHOUGH WE
SHOULD NOTE THAT THE NEW 12Z ECMWF IS TRENDING THIS WAVE A BIT
FARTHER SOUTH.
ON AND OFF AGAIN SHOWERS AND TSTMS CANNOT BE RULED OUT THROUGH THE
EXTENDED WITH WEAK UPPER LEVEL SUPPORT SLIDING THROUGH THE REGION.
KERN
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
318 AM EDT FRI AUG 9 2013
.SYNOPSIS...
HIGH PRESSURE WILL SLOWLY GIVE WAY TO A MORE UNSETTLED PATTERN FOR
THE NEXT SEVERAL DAYS. GENEROUS AMOUNTS OF RAINFALL ARE POSSIBLE
SUNDAY THROUGH MUCH OF NEXT WEEK. A FRONT MAY MOVE FAR ENOUGH
SOUTH LATE NEXT WEEK LEADING TO DRIER CONDITIONS.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 300 AM FRIDAY...SURFACE HIGH PRESSURE OFF THE U.S. EAST COAST
IS DRAWING HOT TROPICAL AIR NORTHWARD FROM THE CARIBBEAN. THE
SUBTROPICAL RIDGE AT 500 THROUGH 200 MB IS NEARLY OVERHEAD AS A
WELL-DEFINED TUTT LOW MOVES WESTWARD UNDER THE RIDGE ACROSS THE
FLORIDA KEYS. 850 MB TEMPERATURES HAVE WARMED ALMOST ANOTHER FULL
DEGREE CELSIUS FROM YESTERDAY WHICH SHOULD GUARANTEE 91-93 ACROSS
MOST OF THE INTERIOR EASTERN CAROLINAS...WITH 88-90 EXPECTED NEAR
THE COAST. IT IS WORTH NOTING THAT THE MARINE ENVIRONMENT IS RIGHT
AT ITS PEAK CLIMATOLOGICAL TEMPERATURES OF THE YEAR AS MEASURED BY
SEA SURFACE AND AIR TEMPERATURE...SO THE COOLING EFFECT PROVIDED BY
THE SEABREEZE HAS REACHED ITS MINIMUM.
STEADY SOUTH-SOUTHWEST WINDS HAVE BEEN BLOWING ALONG THE COAST ALL
MORNING. AS A LANDBREEZE DEVELOPS BETWEEN GEORGETOWN AND SOUTHPORT
AND INTERCEPTS THIS WARM AND HUMID LOW-LEVEL AIRSTREAM...EXPECT A
LINE OF TOWERING CUMULUS AND EVENTUALLY SHOWERS DEVELOP AROUND OR
SHORTLY AFTER DAYBREAK. THE LAST SEVERAL RUNS OF THE HRRR DEPICT
THIS CONVECTION MAINLY REMAINING OFFSHORE...BUT IMPACTING AT LEAST
PORTIONS OF BRUNSWICK AND NEW HANOVER COUNTIES BETWEEN 8-11 AM. AS
HEAT AND HUMIDITY BUILD INLAND LOOK FOR SCATTERED SHOWERS AND
THUNDERSTORMS TO DEVELOP ALONG AND AHEAD OF THE SEABREEZE BOUNDARY
BEGINNING BY NOON. COVERAGE SHOULD AVERAGE ABOUT 30 PERCENT OF THE
AREA DURING THE DAYLIGHT HOURS...AIDED BY STORM MOTION TOWARD THE
NORTHEAST AT 12-15 MPH AND VERY LITTLE CONVECTIVE CAPPING WITHIN AN
AIRMASS CHARACTERIZED BY CAPE 1000-1500 J/KG. THESE SHOULD BE PULSE
STORMS WITH NO SIGNIFICANT WIND OR DRY LAYERS ALOFT AND PRECIPITABLE
WATER AROUND 2.0 INCHES.
CONVECTION SHOULD FALL APART DURING THE EARLY TO MID EVENING HOURS
WITH THE LOSS OF DAYTIME HEATING. MOSTLY CLEAR SKIES ARE EXPECTED
OVERNIGHT WITH LOWS FALLING TO 73-77...WARMEST ALONG THE SOUTH-
FACING BRUNSWICK COUNTY BEACHES.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 300 AM FRIDAY...MID LEVEL RIDGE WILL SLOWLY WEAKEN THROUGH THE PERIOD
AS THE TROPOSPHERE GRADUALLY BECOMES MORE CONDUCIVE FOR CONVECTION.
AT THE SURFACE...TOUGH TO DISTINGUISH BETWEEN AN ACTUAL FRONT OR
TROUGH BUT THE FOCUS WILL BE THE IMPORTANT FACTOR. NUMERICAL
GUIDANCE REFLECTS THIS TREND WITH SLOWLY INCREASING POPS FROM
SATURDAY MORNING THROUGH SUNDAY AFTERNOON. THE OFFICIAL FORECAST
SHOWS THIS AS WELL WITH POPS INITIALLY AT SLIGHT CHANCE TRENDING UP
TO GOOD CHANCE BY SUNDAY PM. PRECIPITABLE WATER VALUES CLIMB FROM
APPROXIMATELY 1.75 INCHES SATURDAY TO NEAR 2.00 INCHES SUNDAY.
SOME MINOR DISAGREEMENT BETWEEN THE MAV AND MET NUMBERS FOR HIGH
TEMPERATURES ESPECIALLY INLAND. WILL LEAN TOWARD THE WARMER MAV
NUMBERS SATURDAY AND SLIGHTLY COOLER MET NUMBERS SUNDAY.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 300 AM FRIDAY...MEDIUM RANGE GUIDANCE CONTINUES TO DEPICT AN EXTENDED
PERIOD OF WET WEATHER AS TROUGHING IS IN PLACE ACROSS THE MIDWEST
AND RIDGING OUT WEST. THERE IS A SIGNAL THAT THE FRONT MAY SLIP FAR
ENOUGH SOUTH VIA THE PREFERRED ECMWF ENSEMBLE MEAN SOLUTION FROM WPC
THAT THURSDAY COULD DRY OUT A BIT. THIS IS REFLECTED IN GRAPHICS
FROM WPC AND IN OUR OFFICIAL FORECAST. WE ARE FORECASTING HIGH
CHANCE POPS AND EVEN A PERIOD...TUESDAY...OF LIKELY POPS WHICH SEEM
WARRANTED. AS MENTIONED LAST NIGHT...I BELIEVE THERE WILL BE MORE
LIKELY POPS WARRANTED AS WE DRAW CLOSER TO THE ONSET OF THE EVENT.
TEMPERATURE TRENDS REMAIN INTACT WITH DAYTIME HIGHS...CERTAINLY
MODULATED BY RAINFALL NEAR CLIMATOLOGY AND OVERNIGHT LOWS A BIT ON
THE HIGH SIDE CITING THE PREVAILING MOISTURE.
&&
.AVIATION /07Z FRIDAY THROUGH TUESDAY/...
AS OF 06Z...A SOUTHWEST LOW LEVEL JET WITH 1000 FT AGL WIND SPEEDS
NEAR 20 KNOTS SHOULD PREVENT FOG FORMATION THROUGH DAYBREAK...BUT
COULD ACTUALLY FAVOR LOW STRATUS DEVELOPMENT INLAND. GFS AND NAM MOS
BOTH SHOW THIS POTENTIAL AT FLO AND LBT...BUT AFTER LAST NIGHT`S
BUST WITH IFR CONDITIONS FORECAST BUT NEVER OCCURRING I AM NOT SO
CERTAIN. FOR NOW I WILL ONLY INCLUDE SCATTERED LOW CLOUDS IN THE
FORECAST...BUT BE AWARE THERE IS SOME POTENTIAL FOR AN HOUR OR TWO
OF IFR CEILINGS AT BOTH FLO AND LBT...MAINLY 10-12Z.
AFTER DAYBREAK...SCATTERED CUMULUS WITH BASES 2000-3000 FT AGL
SHOULD DEVELOP WITH MODERATE SOUTHWEST LOW LEVEL WINDS GUSTING AS
HIGH AS 20 KNOTS AT THE COAST. MUCH LIKE YESTERDAY SCATTERED SHOWERS
MAY DEVELOP FIRST IN THE WILMINGTON AREA...SPREADING INLAND WITH THE
AFTERNOON SEABREEZE.
EXTENDED OUTLOOK...ISOLATED AFTERNOON SHOWERS AND THUNDERSTORMS
POSSIBLE THURSDAY THROUGH SATURDAY...BECOMING SCATTERED SUNDAY
THROUGH TUESDAY...OTHERWISE EXPECT VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 300 AM FRIDAY...HIGH PRESSURE OFF THE U.S. EAST COAST WILL
MAINTAIN A SOUTH-SOUTHWEST WIND ACROSS THE AREA TODAY AND TONIGHT.
HIGH RESOLUTION MODELS INDICATE A LANDBREEZE MAY DEVELOP ALONG THE
SOUTH CAROLINA COAST AROUND DAYBREAK...POTENTIALLY IGNITING
SCATTERED SHOWERS AND EMBEDDED THUNDERSTORMS DURING THE MORNING
HOURS. RADAR IS CURRENTLY CLEAR...BUT THIS PATTERN OF AN EARLY
MORNING LANDBREEZE LEADING TO SHOWERS IS A TYPICAL AUGUST WEATHER
SCENARIO HERE. AS HEAT BUILDS INLAND DURING THE LATE MORNING AND
AFTERNOON HOURS MOST OF THE SHOWER ACTIVITY OVER THE OCEAN SHOULD
DISSIPATE WITH A MODEST SEABREEZE INCREASING WIND SPEEDS TO 15
KNOTS NEAR SHORE. FOR TONIGHT SHOWER CHANCES APPEAR QUITE LOW AS
SOUTH-SOUTHWEST WINDS RETURN TO A STEADY 10-15 KNOTS.
SEAS CURRENTLY AVERAGE 2 FT NEARSHORE WITH 2.5 TO 3 FOOT SEAS
REPORTED FROM THE FRYING PAN SHOALS BUOY. SEAS SHOULD AVERAGE 2-3 FT
THROUGH TONIGHT IN A COMBINATION OF 4 SECOND WIND WAVE AND 9 SECOND
SOUTHEAST SWELL.
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 300 AM FRIDAY...A RELATIVELY WEAK FRONT OR SURFACE TROUGH WILL
REMAIN INLAND ALLOWING A PERSISTENT SOUTHWEST FLOW TO CONTINUE
THOUGH THE PERIOD. WIND SPEEDS WILL BE 10-15 KNOTS. IT APPEARS THERE
IS A LITTLE ENHANCEMENT OF THE LOW LEVEL WIND FIELDS OVERNIGHT
SATURDAY INTO SUNDAY MORNING WHICH WILL TILT THE SPEEDS TO THE
HIGHER END OF THE RANGE. SIGNIFICANT SEAS REMAIN UNCHANGED WITH 2-3
FEET SHORTER PERIOD WIND WAVES.
LONG TERM /MONDAY THROUGH TUESDAY/...
AS OF 300 AM FRIDAY...DIFFUSE FRONT DRAPED ACROSS THE AREA WILL NOT
HAVE A SIGNIFICANT IMPACT ON THE COASTAL WATERS FORECAST AT LEAST
FROM A SYNOPTIC STANDPOINT. SOUTHWEST WINDS OF AROUND TEN KNOTS WILL
PREVAIL WITH SIGNIFICANT SEAS OF 2-4 FEET. THE WAVEWATCH GUIDANCE IS
TRENDING UP FROM 2-3 FEET MONDAY TO 2-4 FEET TUESDAY MAINLY ACROSS
THE OUTER WATERS. PERIODS SHOW WIND WAVES WHICH GIVES ME PAUSE AS
THE WIND FIELDS REMAIN WEAK BUT THE INCREASE ISN/T A SIGNIFICANT
IMPACT ON THE FORECAST.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...SHK
NEAR TERM...TRA
SHORT TERM...SHK
LONG TERM...SHK
AVIATION...SGL
AREA FORECAST DISCUSSION
NWS RALEIGH NC
310 AM EDT FRI AUG 9 2013
.SYNOPSIS...
HIGH PRESSURE OFF THE SOUTHEAST COAST WILL KEEP A MOIST AIR MASS IN
PLACE OVER THE CAROLINAS TODAY. A COLD FRONT WILL MOVE INTO THE
REGION THIS WEEKEND... THEN STALL OVER THE AREA INTO EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 300 AM FRIDAY...
THIS MORNING...
PATCHY CIRRUS IS MOSTLY DISSIPATING OVERHEAD...WITH PARTLY CLOUDY
SKIES OBSERVED OVER THE WESTERN CWA AND NEARLY CLEAR CONDITIONS OVER
THE EAST. A LIGHT SOUTHERLY WIND CONTINUES TO STIR OVER MUCH OF THE
CWA...BUT WHERE WINDS GO CALM...SOME PATCHY FOG MAY BE POSSIBLE
AROUND SUNRISE. THE HRRR ALSO SHOWS SOME SHOWERS DEVELOPING OVER
UPSTATE SC...DRIFTING NORTHEAST INTO THE WESTERN PIEDMONT. WHILE
SOME WEAK MUCAPE ANALYZED ON THE SPC MESO-ANALYSIS WOULD SUPPORT
THIS...THERE HAVE YET TO BE ANY SIGNS OF DEVELOPMENT ON REGIONAL
RADAR.
TODAY...
AS A COLD FRONT MOVES SLOWLY THROUGH THE OHIO VALLEY REGION
TODAY...THE DEEP LAYER FLOW AHEAD OF THE FRONT WILL BECOME MORE
UNIFORM AND SOUTHWESTERLY. THE UPPER LEVEL RIDGE TO OUR SOUTHWEST
WILL CAUSE A COUPLE CONVECTIVELY INDUCED DISTURBANCES UPSTREAM TO
SHEAR OUT AND DRIFT NORTHEAST TOWARD THE MID-ATLANTIC STATES TODAY.
THIS WILL LEAVE LOW-LEVEL CONVERGENCE IN THE FORM OF A
PREFRONTAL/LEE TROUGH AS THE MAIN TRIGGER FOR SCATTERED CONVECTION
THIS AFTERNOON. PW VALUES ARE RATHER HIGH...ABOVE 2 INCHES...BUT
MID-LEVEL LAPSE RATES ARE WEAK AND MLCAPE IS FORECAST TO REMAIN
AROUND 1000 J/KG AT BEST. MOST OF THE HI-RES MODELS SHOW
DEVELOPMENT GENERALLY FROM WINSTON-SALEM TO ROXBORO BY 20Z....WHERE
THE SFC TO 850MB CONVERGENCE IS STRONGEST....DRIFTING EAST THIS
EVENING BUT DYING OFF WITH LOSS OF HEATING. THE SEABREEZE SHOULD
ALSO BE ACTIVE AGAIN...THOUGH SOUTHWESTERLY LOW-LEVEL FLOW WOULD NOT
SUPPORT A STRONG INLAND PUSH.
REGARDING HIGHS...LOW-LEVEL THICKNESSES ARE FORECAST TO BE EQUAL TO
OR GREATER THAN OBSERVED VALUES ON THURSDAY...WHICH WOULD SUPPORT
LEANING TOWARD THE WARMER MAV MOS VALUES OF UPPER 80S AND LOWERS
90S. THIS IS ALSO BE SUPPORTED BY MORE WEST-SOUTHWESTERLY
PRE-FRONTAL FLOW WITH AT LEAST A WEAK DOWNSLOPE COMPONENT.
TONIGHT...
THE COLD FRONT WILL REMAIN TO OUR NORTH TONIGHT...AND INCREASINGLY
WESTERLY 850MB FLOW SHOULD HELP TO LIMIT ANY ADDITIONAL SHOWERS OR
STORMS OVERNIGHT. A CAVEAT TO THIS COULD BE OUTFLOW FROM STORMS TO
OUR NORTH...BUT HI-RES MODELS ARENT SHOWING VERY ROBUST CONVECTION
ALONG THE MAIN FRONTAL ZONE TODAY. THUS...EXPECT MOST OF THE NIGHT
TO BE DRY AFTER MIDNIGHT...WITH MUGGY LOWS IN THE LOWER 70S.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY NIGHT/...
AS OF 300 AM FRIDAY...
SATURDAY AND SATURDAY NIGHT...
THE COLD FRONT TO OUR NORTH IS FORECAST TO SLIDE SOUTH INTO NC AND
ESSENTIALLY STALL THROUGH THE WEEKEND. WITH HIGH PW VALUES AROUND 2
INCHES...MORE FOCUSED LOW-LEVEL CONVERGENCE...AND SLIGHTLY STRONGER
BUT BROAD CYCLONIC FLOW ALOFT...SHOWERS AND STORMS SHOULD BE MORE
NUMEROUS BY EARLY SATURDAY AFTERNOON. SREF PROBABILITIES INDICATE A
MUCH GREATER LIKELIHOOD OF MLCAPE ABOVE 1000 J/KG...AND WITH 25-30KT
OF 0-6KM BULK SHEAR...A FEW CLUSTERS OF STRONG STORMS WITH DAMAGING
WIND GUSTS WILL BE POSSIBLE. A GREATER THREAT MAY BE TRAINING OF
HEAVY DOWNPOURS AS THE STEERING FLOW BECOMES PARALLEL TO THE FRONT.
WILL CONTINUE WITH LIKELY POPS DURING THE DAY SATURDAY AND MAINTAIN
A CHANCE ON SATURDAY NIGHT GIVEN THAT THE FRONT AND VARIOUS OUTFLOW
BOUNDARIES WILL LINGER OVER THE CWA. THICKER CLOUD COVER AND
EARLIER CONVECTIVE INITIATION MAY HOLD TEMPS DOWN TO THE MID/UPPER
80S IN THE NORTH SATURDAY...WHILE LOWER 90S MAY BE MORE COMMON
ACROSS THE SOUTHERN PIEDMONT/COASTAL PLAIN AS THE 850MB THERMAL
RIDGE SHIFT SOUTH. SATURDAY NIGHT LOWS AGAIN IN THE LOWER 70S.
-SMITH
FOR SUNDAY/SUNDAY NIGHT: WILL BE TOUGH TO ESCAPE GETTING WET ON
SUNDAY. THE DIFFUSE FRONTAL ZONE IS LIKELY TO BE SITUATED FROM SE VA
ACROSS NW NC AND BACK NW THROUGH KY... WITH A PRECEDING TROUGH
THROUGH ERN AND SOUTH CENTRAL NC (POTENTIALLY REINFORCED BY
CONVECTIVE OUTFLOW)... WHILE MID LEVEL LONGWAVE TROUGH AMPLIFIES
SLIGHTLY THROUGH SUNDAY NIGHT. DYNAMIC FORCING FOR ASCENT IS WEAK
BUT EVIDENT AT THE MID-UPPER LEVELS... INCLUDING UPPER DIVERGENCE IN
THE RIGHT ENTRANCE REGION OF THE WEAKENING 80 KT WESTERLY JET TO OUR
NE... SUBTLE DPVA WITH ONE WEAK MIDLEVEL WAVE SKIRTING ACROSS VA/NRN
NC SUNDAY... AND 20-30 METER MIDLEVEL HEIGHT FALLS. BUT THE SOMEWHAT
WEAK AND LARGELY WESTERLY LOW LEVEL WIND FIELD SUGGESTS THAT LIFT
ROOTED IN THE LOWER LEVELS MAY BE LIMITED TO SURFACE CONVERGENCE
ALONG THE TROUGH. DEEP LAYER BULK SHEAR IS MARGINAL AT AROUND 20-25
KTS (HIGHEST NORTH) THROUGH MUCH OF SUNDAY/SUNDAY NIGHT... BUT WITH
MLCAPE PROJECTED TO PEAK AT 1200-2000 J/KG (LOWEST NW AND HIGHEST
SE) AND CAPE IN THE MIXED-PHASE REGION TOPPING OUT AT A FAIRLY
RESPECTABLE 500-900 J/KG... A FEW STORMS COULD BECOME STRONG WITH A
RISK OF HAIL. HEAVY RAINERS AND TRAINING/SLOW-MOVING CELLS WILL ALSO
BRING ABOUT A RISK OF LOCALIZED FLOODING GIVEN PW VALUES HOLDING
AROUND 2 INCHES... AND THE WESTERLY FLOW AND HINTS AT AN INVERTED-V
PROFILE INDICATE POSSIBLE STRONG WIND GUSTS AS WELL. BELIEVE WE`LL
SEE GOOD COVERAGE OF CONVECTION EARLY ACROSS THE NORTH... RISING TO
LIKELY AND TRANSLATING SLOWLY TO THE SOUTHEAST THROUGH THE AFTERNOON
AND EVENING... BEFORE TRENDING OUT OF ALL BUT THE FAR EASTERN CWA
OVERNIGHT. HIGHS 86-91 AND LOWS 68-73.
FOR MONDAY/MONDAY NIGHT: THE SURFACE FRONT IS LIKELY TO BECOME EVEN
WEAKER AND MORE DIFFUSE OVER THE REGION MONDAY... AS IT WAITS FOR A
SECOND STRONGER COLD FRONT (ASSOCIATED WITH THE MID LEVEL SHORTWAVE
TROUGH SWINGING THROUGH SRN ONTARIO/SW QUEBEC) TO PUSH SOUTHEASTWARD
THROUGH THE GREAT LAKES/OH VALLEY TOWARD NC. WE MAY SEE ANOTHER
EARLY START TO CONVECTION ALONG THE DYING TROUGH OVER THE
CAROLINAS... AS THE GFS DEPICTS 18Z MLCAPE OF 2000-2500 J/KG AND
-10C TO -30C CAPE REACHING 1000 J/KG AREAWIDE. WHILE DYNAMIC FORCING
FOR LIFT LOOKS EVEN WEAKER MONDAY THAN ON SUNDAY... THE HIGH PW
VALUES ALONG WITH FAVORABLE THERMODYNAMICS AND THE PRESENCE OF A LOW
LEVEL FOCUS SUGGEST WE SHOULD SEE AT LEAST 50-60% COVERAGE OF
SHOWERS/STORMS IN THE AFTERNOON... PARTICULARLY OVER THE CENTRAL AND
SE PORTIONS OF THE FORECAST AREA... WINDING DOWN AS WE HEAD THROUGH
THE EVENING WITH LOSS OF HEATING AND SUBSEQUENT STABILIZATION.
MODELS DIFFER WIDELY ON THICKNESSES... LIKELY DUE IN PART TO
DIFFERENCES IN CLOUD COVER AND PRECIP COVERAGE... BUT GIVEN
EXPECTATIONS OF DECENT MID LEVEL CLOUD COVER THROUGH THIS TIME FRAME
AND POSSIBLE EARLY CONVECTION... WILL HOLD HIGH TEMPS A BIT BELOW
NORMAL... 85-89... WITH NEAR NORMAL LOWS OF 69-73. -GIH
&&
.LONG TERM /TUESDAY THROUGH THURSDAY/...
AS OF 310 AM FRIDAY...
EXPECT CONTINUED ABOVE-NORMAL RAIN CHANCES INTO WEDNESDAY...
FOLLOWED BY DRIER AND COOLER (POTENTIALLY MUCH SO) CONDITIONS FOR
THURSDAY. MODELS DIG THE MIDLEVEL TROUGH DOWN WELL INTO THE EASTERN
CONUS TUESDAY INTO WEDNESDAY... WITH THE SURFACE COLD FRONT PUSHING
TO OUR SOUTH WEDNESDAY. THEY THEN DEPICT THE DEVELOPMENT OF COLD AIR
DAMMING LATE WEDNESDAY AS THE SURFACE FRONT PUSHES JUST TO OUR
SOUTH WHILE CANADIAN HIGH PRESSURE SLIDES BY TO OUR NORTH... ACROSS
THE GREAT LAKES/OH VALLEY TO THE MIDATLANTIC/NORTHEAST. THE
AGREEMENT AMONG THE GFS/ECMWF/CANADIAN REGARDING THIS EVOLUTION IS
ACTUALLY FAIRLY GOOD CONSIDERING IT IS DAYS 5-7 OF THE FORECAST.
WILL KEEP A GOOD CHANCE OF SHOWERS/STORMS (HIGHER SOUTH/EAST)
TUESDAY INTO WEDNESDAY WITH TEMPS TRENDING FROM NEAR NORMAL TO JUST
BELOW NORMAL... THEN WILL GO LARGELY DRY THURSDAY BUT WITH LINGERING
CLOUD COVER AS 850 MB OVERRUNNING FLOW SHOULD RESUME BY LATE IN THE
DAY. GFS/ECMWF THICKNESSES PLUNGE TO AROUND 30 METERS BELOW NORMAL
THURSDAY... SUGGESTING HIGHS OF 77-83. -GIH
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
AS OF 145 AM FRIDAY...
MOSTLY VFR CONDITIONS ACROSS CENTRAL NC EARLY THIS MORNING. SOME OF
THE HIGH RESOLUTION MODELS ARE SHOWING THE DEVELOPMENT OF SHOWERS
OVER UPSTATE SC THROUGH 09Z...WHICH WOULD THEN DRIFT NORTHEAST INTO
THE WESTERN PIEDMONT OF NC. HOWEVER...THERE HAVE YET TO BE ANY
SIGNS OF SHOWER ACTIVITY...SO THE MAIN CONCERN FOR KGSO AND KINT
WILL BE STRATUS JUST PRIOR TO SUNRISE. GIVEN THAT THE PATTERN HAS
NOT CHANGED VERY MUCH OVER THE PAST 24 HOURS AND THERE WAS VERY
LITTLE STRATUS THURSDAY MORNING...THE CURRENT THINKING IS THAT ANY
IFR/MVFR CEILINGS WILL BE VERY BRIEF BETWEEN 10Z AND 13Z. TO THE
EAST...WHERE SKIES ARE ESSENTIALLY CLEAR AT THE MOMENT...IFR AND
MVFR VSBYS ARE MORE LIKELY IF WINDS GO CALM. AGAIN...THIS APPEARS
TO BE A THREAT TO OCCUR AROUND SUNRISE...WITH VFR CONDITIONS TO
PREVAIL BY 15Z. SCATTERED SHOWERS AND STORMS SHOULD DEVELOP THIS
AFTERNOON...MOSTLY LIKELY IMPACTING KGSO AND KINT AFTER 20Z.
OUTLOOK...
EXPECT AN ABOVE AVERAGE CHANCE FOR SHOWERS AND THUNDERSTORMS
(PRIMARILY AFTERNOON AND EVENING HOURS) SATURDAY THROUGH EARLY TO
MID NEXT WEEK AS A FRONT APPROACHES FROM THE NORTH AND THEN STALLS
OVER THE CAROLINAS/VA IN THE PRESENCE OF CYCLONIC FLOW ALOFT.
MORNING FOG OR STRATUS WILL ALSO BE POSSIBLE EACH DAY... PRIMARILY
IN THE 08-14Z TIME FRAME.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...SMITH
NEAR TERM...SMITH
SHORT TERM..SMITH/HARTFIELD
LONG TERM...HARTFIELD
AVIATION...SMITH/BSD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
305 AM EDT FRI AUG 9 2013
.SYNOPSIS...
HIGH PRESSURE OFF THE SOUTHEAST COAST WILL KEEP A MOIST AIR MASS IN
PLACE OVER THE CAROLINAS TODAY. A COLD FRONT WILL MOVE INTO THE
REGION THIS WEEKEND... THEN STALL OVER THE AREA INTO EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 300 AM FRIDAY...
THIS MORNING...
PATCHY CIRRUS IS MOSTLY DISSIPATING OVERHEAD...WITH PARTLY CLOUDY
SKIES OBSERVED OVER THE WESTERN CWA AND NEARLY CLEAR CONDITIONS OVER
THE EAST. A LIGHT SOUTHERLY WIND CONTINUES TO STIR OVER MUCH OF THE
CWA...BUT WHERE WINDS GO CALM...SOME PATCHY FOG MAY BE POSSIBLE
AROUND SUNRISE. THE HRRR ALSO SHOWS SOME SHOWERS DEVELOPING OVER
UPSTATE SC...DRIFTING NORTHEAST INTO THE WESTERN PIEDMONT. WHILE
SOME WEAK MUCAPE ANALYZED ON THE SPC MESO-ANALYSIS WOULD SUPPORT
THIS...THERE HAVE YET TO BE ANY SIGNS OF DEVELOPMENT ON REGIONAL
RADAR.
TODAY...
AS A COLD FRONT MOVES SLOWLY THROUGH THE OHIO VALLEY REGION
TODAY...THE DEEP LAYER FLOW AHEAD OF THE FRONT WILL BECOME MORE
UNIFORM AND SOUTHWESTERLY. THE UPPER LEVEL RIDGE TO OUR SOUTHWEST
WILL CAUSE A COUPLE CONVECTIVELY INDUCED DISTURBANCES UPSTREAM TO
SHEAR OUT AND DRIFT NORTHEAST TOWARD THE MID-ATLANTIC STATES TODAY.
THIS WILL LEAVE LOW-LEVEL CONVERGENCE IN THE FORM OF A
PREFRONTAL/LEE TROUGH AS THE MAIN TRIGGER FOR SCATTERED CONVECTION
THIS AFTERNOON. PW VALUES ARE RATHER HIGH...ABOVE 2 INCHES...BUT
MID-LEVEL LAPSE RATES ARE WEAK AND MLCAPE IS FORECAST TO REMAIN
AROUND 1000 J/KG AT BEST. MOST OF THE HI-RES MODELS SHOW
DEVELOPMENT GENERALLY FROM WINSTON-SALEM TO ROXBORO BY 20Z....WHERE
THE SFC TO 850MB CONVERGENCE IS STRONGEST....DRIFTING EAST THIS
EVENING BUT DYING OFF WITH LOSS OF HEATING. THE SEABREEZE SHOULD
ALSO BE ACTIVE AGAIN...THOUGH SOUTHWESTERLY LOW-LEVEL FLOW WOULD NOT
SUPPORT A STRONG INLAND PUSH.
REGARDING HIGHS...LOW-LEVEL THICKNESSES ARE FORECAST TO BE EQUAL TO
OR GREATER THAN OBSERVED VALUES ON THURSDAY...WHICH WOULD SUPPORT
LEANING TOWARD THE WARMER MAV MOS VALUES OF UPPER 80S AND LOWERS
90S. THIS IS ALSO BE SUPPORTED BY MORE WEST-SOUTHWESTERLY
PRE-FRONTAL FLOW WITH AT LEAST A WEAK DOWNSLOPE COMPONENT.
TONIGHT...
THE COLD FRONT WILL REMAIN TO OUR NORTH TONIGHT...AND INCREASINGLY
WESTERLY 850MB FLOW SHOULD HELP TO LIMIT ANY ADDITIONAL SHOWERS OR
STORMS OVERNIGHT. A CAVEAT TO THIS COULD BE OUTFLOW FROM STORMS TO
OUR NORTH...BUT HI-RES MODELS ARENT SHOWING VERY ROBUST CONVECTION
ALONG THE MAIN FRONTAL ZONE TODAY. THUS...EXPECT MOST OF THE NIGHT
TO BE DRY AFTER MIDNIGHT...WITH MUGGY LOWS IN THE LOWER 70S.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY NIGHT/...
AS OF 300 AM FRIDAY...
SATURDAY AND SATURDAY NIGHT...
THE COLD FRONT TO OUR NORTH IS FORECAST TO SLIDE SOUTH INTO NC AND
ESSENTIALLY STALL THROUGH THE WEEKEND. WITH HIGH PW VALUES AROUND 2
INCHES...MORE FOCUSED LOW-LEVEL CONVERGENCE...AND SLIGHTLY STRONGER
BUT BROAD CYCLONIC FLOW ALOFT...SHOWERS AND STORMS SHOULD BE MORE
NUMEROUS BY EARLY SATURDAY AFTERNOON. SREF PROBABILITIES INDICATE A
MUCH GREATER LIKELIHOOD OF MLCAPE ABOVE 1000 J/KG...AND WITH 25-30KT
OF 0-6KM BULK SHEAR...A FEW CLUSTERS OF STRONG STORMS WITH DAMAGING
WIND GUSTS WILL BE POSSIBLE. A GREATER THREAT MAY BE TRAINING OF
HEAVY DOWNPOURS AS THE STEERING FLOW BECOMES PARALLEL TO THE FRONT.
WILL CONTINUE WITH LIKELY POPS DURING THE DAY SATURDAY AND MAINTAIN
A CHANCE ON SATURDAY NIGHT GIVEN THAT THE FRONT AND VARIOUS OUTFLOW
BOUNDARIES WILL LINGER OVER THE CWA. THICKER CLOUD COVER AND
EARLIER CONVECTIVE INITIATION MAY HOLD TEMPS DOWN TO THE MID/UPPER
80S IN THE NORTH SATURDAY...WHILE LOWER 90S MAY BE MORE COMMON
ACROSS
THE SOUTHERN PIEDMONT/COASTAL PLAIN AS THE 850MB THERMAL RIDGE SHIFT
SOUTH. SATURDAY NIGHT LOWS AGAIN IN THE LOWER 70S. -SMITH
&&
.LONG TERM /TUESDAY THROUGH THURSDAY/...
AS OF 230 PM THURSDAY...
UPDATED SHORTLY...
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
AS OF 145 AM FRIDAY...
MOSTLY VFR CONDITIONS ACROSS CENTRAL NC EARLY THIS MORNING. SOME OF
THE HIGH RESOLUTION MODELS ARE SHOWING THE DEVELOPMENT OF SHOWERS
OVER UPSTATE SC THROUGH 09Z...WHICH WOULD THEN DRIFT NORTHEAST INTO
THE WESTERN PIEDMONT OF NC. HOWEVER...THERE HAVE YET TO BE ANY
SIGNS OF SHOWER ACTIVITY...SO THE MAIN CONCERN FOR KGSO AND KINT
WILL BE STRATUS JUST PRIOR TO SUNRISE. GIVEN THAT THE PATTERN HAS
NOT CHANGED VERY MUCH OVER THE PAST 24 HOURS AND THERE WAS VERY
LITTLE STRATUS THURSDAY MORNING...THE CURRENT THINKING IS THAT ANY
IFR/MVFR CEILINGS WILL BE VERY BRIEF BETWEEN 10Z AND 13Z. TO THE
EAST...WHERE SKIES ARE ESSENTIALLY CLEAR AT THE MOMENT...IFR AND
MVFR VSBYS ARE MORE LIKELY IF WINDS GO CALM. AGAIN...THIS APPEARS
TO BE A THREAT TO OCCUR AROUND SUNRISE...WITH VFR CONDITIONS TO
PREVAIL BY 15Z. SCATTERED SHOWERS AND STORMS SHOULD DEVELOP THIS
AFTERNOON...MOSTLY LIKELY IMPACTING KGSO AND KINT AFTER 20Z.
OUTLOOK...
EXPECT AN ABOVE AVERAGE CHANCE FOR SHOWERS AND THUNDERSTORMS
(PRIMARILY AFTERNOON AND EVENING HOURS) SATURDAY THROUGH EARLY TO
MID NEXT WEEK AS A FRONT APPROACHES FROM THE NORTH AND THEN STALLS
OVER THE CAROLINAS/VA IN THE PRESENCE OF CYCLONIC FLOW ALOFT.
MORNING FOG OR STRATUS WILL ALSO BE POSSIBLE EACH DAY... PRIMARILY
IN THE 08-14Z TIME FRAME.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...SMITH
NEAR TERM...SMITH
SHORT TERM..SMITH
LONG TERM...MLM/BAS
AVIATION...SMITH/BSD
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
354 AM CDT FRI AUG 9 2013
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 354 AM CDT FRI AUG 9 2013
PRIMARY CONCERNS TODAY ARE CLOUD COVER...TEMPERATURES...AND LOW
PRECIPITATION CHANCES. GFS/NAM/ECMWF/GEM ARE IN GOOD AGREEMENT AND
WILL USE A BLENDED SOLUTION FOR THIS FORECAST PACKAGE.
CLOSED 500 HPA LOW ACROSS CENTRAL ONTARIO WILL FINALLY BEGIN TO
PUSH EAST TODAY...ENTERING WESTERN QUEBEC BY 06 UTC TONIGHT.
ANOTHER SHORT-WAVE WILL SWING ACROSS THE FORECAST AREA WITH THE
PRIMARY IMPACT BEING A BAND OF STRATOCU AND LIGHT RAIN SHOWERS.
LATEST 925 TO 850 HPA RH FROM THE RAP SHOWS THESE CLOUDS MOVING AS
FAR SOUTH AS A LINE FROM LANGDON TO GRAND FORKS TO BEMIDJI BEFORE
BEGINNING TO DISSIPATE AND MOVE OUT THE REGION LATER THIS EVENING.
AS A RESULT...INCREASED SKY COVER ACROSS THE NORTHEASTERN THIRD OF
THE FORECAST AREA. ALSO ADDED ISOLATED SHOWER MENTION MAINLY
ACROSS ROSEAU/LAKE OF THE WOODS COUNTIES FROM 15 UTC TO 00 UTC
NOTING RECENT LIGHT RAIN REPORTS AT WINNIPEG AND AREAS UPSTREAM.
AREAS UNDER CLOUD COVER WILL STAY COOL TODAY WITH AFTERNOON HIGHS
MAINLY IN THE MID TO UPPER 60S...PERHAPS REACHING THE LOWER 70S
ALONG THE NORTHERN VALLEY FLOOR. AREAS SOUTH AND WEST WILL SEE
SOME AFTERNOON THERMAL CU GIVEN CONVECTIVE TEMPERATURES IN THE
UPPER 60S TO LOWER 70S...BUT SHOULD SEE ENOUGH SUN FOR HIGHS INTO
THE LOWER TO MID 70S.
SURFACE RIDGE WILL REMAIN ENTRENCHED ACROSS THE REGION OVERNIGHT...
RESULTING IN LIGHT WIND AND SOME DEGREE OF CLEARING ALTHOUGH DO
EXPECT SOME LINGERING CLOUD COVER FROM DEPARTING SHORT-WAVE.
OVERNIGHT LOWS WILL DROP INTO THE UPPER 40S TO NEAR 50 DEGREES.
MODELS HAVE SHIFTED A WARM AIR ADVECTION-INDUCED CONVECTIVE COMPLEX
FRIDAY NIGHT INTO SATURDAY AND SATURDAY NIGHT ALMOST ENTIRELY
SOUTH OF THE ND/SD BORDER. CUT POPS ACROSS ALL BUT THE FAR
SOUTHERN FORECAST AREA AND THIS MAY STILL BE TOO OPTIMISTIC. WILL
KEEP AREAS ACROSS THE NORTH DRY FOR NOW...BUT THERE IS ANOTHER
CANADIAN SHORT-WAVE THAT DROPS ACROSS THE REGION THAT COULD RESULT
IN SOME ISOLATED SHOWERS AWAY FROM THE MAIN CLUSTER ACROSS
SD/SOUTHERN MN. FILTERED SUNSHINE AND LIGHT WINDS SATURDAY WILL
ALLOW TEMPERATURES TO CLIMB INTO THE LOW TO MIDDLE 70S.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 354 AM CDT FRI AUG 9 2013
WITH THE EXCEPTION OF PERHAPS SOME LINGERING LIGHT SHOWERS ACROSS
THE FAR SOUTHEASTERN FORECAST AREA...SUNDAY WILL BE ANOTHER
TRANQUIL DAY WEATHER-WISE AS HIGH PRESSURE CONTINUES ACROSS THE
REGION. ABUNDANT SUNSHINE AND RISING MID-LEVEL THERMAL FIELDS WILL
RESULT IN TEMPERATURES IN THE MID TO UPPER 70S.
MONDAY TO THURSDAY...MODELS IN GOOD AGREEMENT WITH AN OVERALL DRY
PERIOD AS 500MB NW FLOW WITH SFC HIGH PRESSURE DOMINATES THE
WEATHER PATTERN ACROSS THE NORTHERN PLAINS FOR THE FIRST HALF OF
NEXT WEEK. EXPECTED DAYTIME HIGHS TO RISE A DEGREE OR TWO EACH DAY
WITH UPPER 70S ON MONDAY TO LOW 80S...NORMAL FOR MID AUGUST...BY
WEDNESDAY. THERE IS A CHC FOR SOME CONVECTIVE ACTIVITY IN THE AREA
ON WEDNESDAY NIGHT INTO THURSDAY AS A SHORTWAVE SYSTEM IS PROGGED
TO SLIDE OVER THE REGION.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1137 PM CDT THU AUG 8 2013
VFR CONDITIONS THROUGH THE PERIOD. SCATTERED 5-8K FT CLOUDS
TONIGHT INTO FRI AM THEN LIKELY BROKEN CUMULUS DEVELOPMENT ESP NE
ND INTO NRN MN WITH DAYTIME HEATING FRI AFTN IN THE 5-7K FT RANGE.
WINDS LIGHT/VARIABLE TONIGHT AND GENERALLY NORTHWEST 5 TO 10 KTS
FRIDAY.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
SHORT TERM...ROGERS
LONG TERM...ROGERS/JK
AVIATION...RIDDLE
AREA FORECAST DISCUSSION
NWS BISMARCK ND
129 AM CDT FRI AUG 9 2013
.UPDATE...
ISSUED AT 130 AM CDT FRI AUG 9 2013
EMBEDDED MID LEVEL ENERGY/SUBTLE SHORTWAVE TROUGHS CONTINUE TO
TRACK ACROSS THE REGION IN NORTHWEST FLOW ALOFT. THUS FAR MAIN
RESULT HAS BEEN AN INCREASE IN MID LEVEL CLOUDS OVER WEST AND
CENTRAL NORTH DAKOTA. SCATTERED SHOWERS OVER NORTHEAST MONTANA
MOVING SLOWLY SOUTHEAST. FOR NOW LEFT THE FORECAST DRY ACROSS MY
WEST AS UNSURE WHETHER THESE SHOWERS WILL MAKE IT TO THE WESTERN
ND BORDER OR NOT. LINE OF THUNDERSTORMS FROM SOUTHEAST MONTANA INTO
THE BLACK HILLS OF WESTERN SOUTH DAKOTA NEAR A STATIONARY
BOUNDARY. A FEW MODELS TRY TO DEVELOP PRECIPITATION OVER MY
SOUTHWEST BETWEEN NOW AND 12Z...POSSIBLY ASSOCIATED WITH THE WAVE
GENERATING SHOWERS NORTH OF GLASGOW/WOLF POINT AT THE MOMENT.
MAIN UPDATE WAS TO INCREASE CLOUDS A BIT WEST AND CENTRAL...AND
ADJUST HOURLY WEATHER ELEMENTS BASED ON LATEST OBSERVATIONS/TRENDS.
UPDATE ISSUED AT 906 PM CDT THU AUG 8 2013
LATEST SATELLITE IMAGERY AND REGIONAL RADAR SHOWS THE SHORTWAVE IN
FAR SOUTHERN SASKATCHEWAN IS WEAKENING WITH TIME AS SHOWERS
CONTINUE TO WEAKEN AS THEY MOVE INTO FAR NORTHWEST NORTH DAKOTA.
WILL CARRY A SLIGHT CHANCE FOR THE NEXT HOUR OR TWO MAINLY FOR
DIVIDE COUNTY. OTHERWISE DRY AND MOSTLY CLEAR FOR ALL AREAS EXCEPT
IN THE FAR SOUTHWEST WHERE CLOUD DEBRIS IS QUICKLY APPROACHING FAR
SOUTHEAST MONTANA AND NORTHWEST SOUTH DAKOTA. THE RAP MAINTAINS
SOME LIGHT PRECIPITATION CHANCES DEVELOPING IN THE FAR SOUTHWEST
AS A SHORTWAVE PUSHES THROUGH SOUTH CENTRAL MONTANA. INSTABILITY
REMAINS WEAK AND WILL CONTINUE TO MONITOR FOR THE POSSIBILITY OF A
SHOWER OR TWO DEVELOPING AFTER MIDNIGHT...HOWEVER THE 00Z NAM IS
DRY...SO NOT REAL CONFIDENT IN THIS OCCURRING. LOOKING AHEAD...SLIGHTLY
BETTER INSTABILITY REACHES FAR SOUTHWESTERN NORTH DAKOTA FRIDAY
AFTERNOON/EVENING FOR CHANCE OF SHOWERS AND THUNDERSTORMS. WILL
ADJUST SKY GRIDS IN THE NORTHWEST AND SOUTHWEST TO ACCOUNT FOR THE
INCREASE IN CLOUDS. OTHER UPDATES WERE MAINLY TO HOURLY SENSIBLE
WEATHER ELEMENTS.
UPDATE ISSUED AT 457 PM CDT THU AUG 8 2013
LATEST WATER VAPOR IMAGERY SHOWS NORTHWEST FLOW CONTINUING WITH AN
UPSTREAM MID LEVEL SHORTWAVE LOCATED IN SOUTH CENTRAL SASKATCHEWAN.
REGIONAL RADAR SHOWS ISOLATED RAIN SHOWERS JUST NORTH OF THE MONTANA
BORDER MOVING SOUTHEAST WITH TIME. LIGHT RAIN AT SWIFT CURRENT PER
LATEST SURFACE OBSERVATIONS AND THE GFS HAS THE BEST HANDLE ON THE
PRECIPITATION AREA...WITH THE RAP NOT FAR BEHIND. THE GFS HOLDS A
THIN AREA OF LIGHT SHOWERS TOGETHER AS THEY MOVE INTO NORTHWESTERN
NORTH DAKOTA THIS EVENING AND WILL FOLLOW. THE RAP SHOWS A WEAKENING
OF THE SHOWERS AND KEEPS IT DRY. BASED ON THE LATEST RADAR AND
SURFACE OBSERVATIONS...THINK ENOUGH EVIDENCE UPSTREAM AND IN THE
GFS SOLUTION TO SOLIDIFY A MENTION OF ISOLATED SHOWERS NORTHWEST
INTO PORTIONS OF NORTH CENTRAL TONIGHT. THE GFS H7-H5 RELATIVE
HUMIDITY FIELD ALSO MATCHES THE VISIBLE SATELLITE IMAGERY WELL WHEN
OVERLAID AND THUS WILL INCREASE SKY GRIDS A BIT TO CAPTURE THIS.
ALSO AS MENTIONED FROM THE PREVIOUS DISCUSSION BELOW THE OTHER INTEREST
OVERNIGHT COULD BE OUR FAR SOUTHWEST ZONES...WHERE CONVECTION OVER
NORTHERN WYOMING THIS AFTERNOON IS FORECAST TO BUILD FURTHER NORTH
AND POSSIBLY SEEP INTO THE SOUTHWEST BY AROUND 04Z FRIDAY...PER
RAP MODEL. THE HRRR MODEL HAS CHANGED ITS COURSE BY KEEPING THE
REFLECTIVITY`S SOUTH WHEREAS EARLIER IT ALSO MAKE A TRACK INTO
SOUTHWEST NORTH DAKOTA. WILL CONTINUE TO MONITOR...OTHERWISE
MOSTLY CLEAR TO PARTLY CLOUDY SKIES CAN BE ANTICIPATED FOR THE
REST OF WESTERN AND CENTRAL NORTH DAKOTA THIS EVENING INTO TONIGHT.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 317 PM CDT THU AUG 8 2013
CURRENTLY...HIGH PRESSURE CONTINUES TO BUILD ACROSS WESTERN AND
CENTRAL NORTH DAKOTA. THE COOL HIGH PRESSURE SUPPRESS AND
THUNDERSTORM ACTIVITY LAT THIS AFTERNOON AND TONIGHT. BUT A FEW
SPRINKLES OR AN ISOLATED SHOWER CANNOT BE RULED OUT LATE THIS
AFTERNOON.
TONIGHT...THE SURFACE HIGH PRESSURE RIDGE REMAINS SITUATED
NORTHWEST TO SOUTHEAST ACROSS THE CWA...WHILE SHORTWAVE ENERGY
APPROACHES EASTERN NORTH DAKOTA AND ALSO SOUTHWEST NORTH DAKOTA.
THIS WILL LIKELY RESULT IN LITTLE MORE THAN INCREASING CLOUDS OVER
THE SOUTHWEST AND SOUTH CENTRAL LATE TONIGHT. SOME OF THE MODELS
ARE INDICATING VERY LIGHT QPF IN THE SOUTHWEST BETWEEN 06-12Z
FRIDAY. BUT FOR NOW KEPT WITH THE CURRENT DRY FORECAST. EXPECT A
COOL NIGHT WITH HIGHS RANGING FROM THE MID 40S FAR NORTH TO THE
LOW TO MID 50S FAR SOUTH.
SHORTWAVE ENERGY WORKING THROUGH A NORTHERN ROCKIES UPPER RIDGE
WILL SUPPORT SHOWERS AND THUNDERSTORMS ACROSS SOUTHEAST
MONTANA...NORTHERN WYOMING AND WESTERN SOUTH DAKOTA FRIDAY
AFTERNOON. IT IS POSSIBLE THAT A FEW OF THESE SHOWERS OR
THUNDERSTORMS COULD MOVE INTO THE SOUTHWEST FRIDAY AFTERNOON.
HOWEVER...GUIDANCE CONTINUES TO TREND FARTHER SOUTH SO WILL
CONTINUE WITH PERSISTENCE AND KEEP THINGS DRY ON FRIDAY.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 317 PM CDT THU AUG 8 2013
A SLOW WARMING TREND POTENTIALLY BACK TO NEAR NORMAL TEMPERATURES
NEXT WEEK WILL HIGHLIGHT THE EXTENDED FORECAST.
THE 12 UTC GUIDANCE SUITE IS IN GOOD AGREEMENT ON NORTHWEST FLOW
ALOFT CONTINUING THROUGH MONDAY...BEFORE A POTENTIAL SHIFT OF THE
UPPER LEVEL RIDGE AXIS ACROSS THE NORTHERN PLAINS TUESDAY ONWARD.
THIS WOULD SUPPORT A SLOW WARMING TREND FROM THE RECENT BELOW NORMAL
TEMPERATURES TO WIDESPREAD HIGHS IN THE 80S BY MID TO LATE NEXT
WEEK. IN REGARDS TO PRECIPITATION CHANCES...THERE IS CHANCE OF
THUNDERSTORMS SATURDAY AND SATURDAY NIGHT AS THE LAST OF THE
SIGNIFICANT WAVES EMBEDDED IN NORTHWEST FLOW PROPAGATES ACROSS THE
NORTHERN PLAINS. THEREAFTER...THUNDERSTORM CHANCES HOLD OFF UNTIL
MID TO LATE NEXT WEEK WITH INCREASING MOISTURE TRANSPORT UNDER THE
RIDGE AHEAD OF LEE SURFACE LOW PRESSURE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 130 AM CDT FRI AUG 9 2013
VFR CONDITIONS THROUGH THE 06Z TAF PERIOD. WILL SEE SCT-BKN MID
LEVEL CLOUDS AT TIMES EARLY TO MID MORNING FOR ALL LOCATIONS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...NH
SHORT TERM...TWH
LONG TERM...AYD
AVIATION...NH
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
149 AM EDT FRI AUG 9 2013
.SYNOPSIS...
MOISTURE AND INSTABILITY PERSISTS INTO THE WEEKEND WITH ROUNDS OF
SHOWERS AND THUNDERSTORMS. COLD FRONT SAGS SLOWLY SOUTH THROUGH
VICINITY SATURDAY INTO SATURDAY NIGHT.
&&
.NEAR TERM /THROUGH TODAY/...
1015 PM UPDATE...
DECREASED POPS FURTHER THIS EVE MOST PLACES BASED ON RADAR
TRENDS...STILL KEEPING ISO COVERAGE WORDING THOUGH. HAVE SOME LKLY
IN N MTNS NEXT FEW HRS TO FOLLOW CONCENTRATION OF SHRA. STILL ON
TRACK FOR INCREASE IN SHRA TOWARD MORNING W HALF OF CWA.
745 PM UPDATE...
THINGS QUIETING DOWN THIS EVE WITH MOST OF THE SHRA CLOSER TO
FRONT IN OH. SOME SHRA NOTED TRAVERSING THRU THE MTNS AND
LOWLANDS. WITH HI RES MDLS NOT SHOWING MUCH THRU 06Z ASIDE FROM SE
OH...WILL DROP POPS MOST PLACES...GOING WITH MOSTLY ISO LATER THIS
EVE. THINK MORE SHRA IN THE CARDS...THOUGH...AS SFC FRONT TRIES
TO INCH S INTO PORTIONS OF SE OH. HRRR TRENDS BACK THIS UP WITH
SHRA MOVING BACK IN W HALF OF CWA AFTER 06Z.
PREVIOUS DISCUSSION BELOW...
ACTIVE WEATHER CONTINUES FOR THE NEAR TERM AND BEYOND...WITH THE
PRIMARY FORECAST CONCERN REVOLVING AROUND PRECIP AMOUNTS EXPECTED
ALONG WITH SUBSEQUENT FLOODING POTENTIAL.
AT 18Z RADAR DEPICTING A NORTH/SOUTH BROKEN LINE OF SHOWERS WITH
SOME THUNDER MOVING EASTWARD ACROSS THE CENTRAL PART OF THE FORECAST
AREA. SFC FRONT CURRENTLY LOCATED ROUGHLY JUST SOUTH OF CLEVELAND
OHIO W/SW-WARD TO JUST NORTH OF DAYTON OHIO...WITH EXPECTED
DEVELOPING SHOWERS/THUNDERSTORMS NEAR IT AS WELL. LINE OF SHOWERS
CURRENTLY BISECTING AREA WILL CONTINUE EAST INTO THE MOUNTAINS BY
LATE AFTERNOON...WITH SHOWERS/STORMS ON THE FRONT TO PUSH E/NE-WARD
AND EVENTUALLY MAKING INTO PARTS OF THE NW ZONES BY LATE
AFTERNOON/EARLY EVE. NOT EXPECTING MUCH IN THE WAY OF A SEVERE
THREAT WITH THESE STORMS FOR OUR AREA...BUT SIMILAR TO YESTERDAY...A
MARGINAL THREAT FOR A SEVERE STORM EXISTS MAINLY TO THE NORTH AND
NORTHWEST OF THE FORECAST AREA.
OVERNIGHT ANY ONGOING CONVECTION WILL CONTINUE TO SLIDE EASTWARD
MAINLY ACROSS NORTHERN ZONES WHILE DIMINISHING IN COVERAGE AND
STRENGTH AS INSTABILITY WANES. SHOULD SEE THE NORMAL LULL IN
OVERNIGHT PRECIP COVERAGE INITIALLY BUT WILL LEAVE LOW/MID CHANCE
POPS IN THE EARLY OVERNIGHT HOURS. BY AND AFTER 06Z THE NEXT IN THE
SERIES OF VORT MAXES APPROACHES THE WESTERN ZONES WITH SFC LOW
RIDING ALONG THE STALLED FRONT JUST TO THE NW OF THE AREA. TOUGH TO
KNOW HOW MUCH TO INCREASE POPS WITH THESE FEATURES BUT WILL BRING IN
HIGHER POPS ACROSS THE WEST QUICKER THAN THE USUAL DIURNAL
TREND...BY 09Z-12Z FRI. THIS VORT MAX QUICKLY PUSHES OFF TO THE EAST
WHILE BEING REPLACED BY A STRONGER VORT MAX PROGGED TO MOVE ACROSS
NORTHERN ZONES DURING THE AFTERNOON. AS SFC LOW CONTINUES TO PULL
AWAY TO THE NORTH THE COLD FRONT ATTEMPTS TO PUSH SOUTHEAST A BIT
AND FOR A TIME AFTER 18Z FRI-00Z SAT MAY BE LOCATED OVER OUR SE OHIO
ZONES. STILL EXPECT THE HIGHEST GENERAL COVERAGE OF PRECIP TO BE
NEAR AND OUT AHEAD OF THE VORT MAX BUT MAY SEE SOME REDEVELOPMENT
ALONG THE FRONT ITSELF FURTHER WEST.
REGARDING FLASH FLOODING POTENTIAL...THE GENERAL CONSENSUS OF PRECIP
MODEL OUTPUT RUNNING AROUND 1.00IN - 1.50IN. THE AREA IS AND HAS
BEEN MOSTLY DRY RECENTLY. WHILE NOT APPEARING TO BE A WIDESPREAD
FLOOD THREAT...WITH TALL STORMS AND PWATS AT AND OVER 2.00IN AND
STORM MOTION AROUND 10-15KTS...STORMS SHOULD BE GOOD RAINMAKERS.
WILL CONTINUE THE FLASH FLOOD WATCH MAINLY FOR THE POTENTIAL OF SOME
LOCALIZED FLASH FLOODING...WITH THE HIGHEST THREAT APPEARING TO COME
EARLY FRIDAY AT THIS POINT IN TIME.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY/...
FRONTAL BOUNDARY STALLED OUT ALONG NORTHERN ZONES FRIDAY NIGHT...BUT
WILL SLOWLY SAG SOUTH ACROSS THE CWA ON SATURDAY...WITH A GRADUAL
DRYING TREND NORTH TO SOUTH AS IT DOES SO. KEPT HEAVY RAIN WORDING
INT HE FORECAST FOR FRIDAY NIGHT...AS PW VALUES ARE PROGGED TO STILL
BE OVER 2 INCHES. FRONTAL BOUNDARY WILL END UP TO THE SOUTH OF THE
CWA BY SUNDAY MORNING. WILL STILL BE A CHANCE FOR SOME SHOWER/STORM
ACTIVITY ALONG THE EXTREME SOUTHERN/EASTERN ZONES AS WAVES CONTINUE
TO PUSH EAST ACROSS THE FRONTAL BOUNDARY...BUT THE BULK OF THE CWA
SHOULD BE IN DRIER...AND SOMEWHAT COOLER WEATHER. AS WITH PREVIOUS
FORECAST...CONTINUED TO TREND MORE TOWARDS THE GFS/ECMWF SOLUNS
WHICH INDICATE A WAVE...AND THUS HIGHER POPS MOVING ACROSS
SOUTHERN/CENTRAL ZONES FRIDAY NIGHT/SATURDAY.
AS STATED PREVIOUSLY...THE FFA MAY BE ABLE TO BE TRIMMED EARLY
ACROSS THE NORTHERN ZONES FRIDAY NIGHT AS THIS FRONTAL BOUNDARY
STARTS TO SINK SOUTH ACROSS THE CWA.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
EXTENDED PERIOD STARTS OUT DRIER AS FRONTAL BOUNDARY TO THE SOUTH OF
THE CWA...AND HIGH PRESSURE BRIEFLY BUILDS IN FROM THE NORTH.
HOWEVER...MOISTURE AND HUMIDITY WILL BE ON THE INCREASE ONCE AGAIN
BY LATE MONDAY NIGHT INTO TUESDAY...AS A LOW PRESSURE SYSTEM...AND
COLD FRONTAL BOUNDARY APPROACH AND MOVE THROUGH THE AREA THROUGH MID
WEEK. INCREASED POPS TO AT LEAST CHANCE-HIGH CHANCE CATEGORY
EARLY-MID WEEK. COULD SEE HEAVY DOWNPOURS ASSOCIATED WITH ANY
SHOWERS/STORMS AS PW VALUES WILL ONCE AGAIN RISE UP TO AROUND
1.7-1.9 INCHES...AND DEPENDING ON WHAT HAPPENS OVER THE NEXT FEW
DAYS/INTO THE WEEKEND...COULD DETERMINE WHETHER OR NOT ANY LOCALIZED
WATER ISSUES WILL BE A CONCERN.
FRONTAL BOUNDARY SINKS TO THE SOUTH ON THURSDAY...WITH DRIER AND
COOLER WEATHER IN ITS WAKE.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
06Z FRIDAY THRU 06Z SATURDAY...
VERY MOIST AND UNSTABLE AIRMASS IN PLACE WITH THREAT OF SHOWERS AND
STORMS IN OUR COUNTY WARNING AREA(CWA). WITH THE MODEL AGREED MAIN
SHORT WAVE...BEST CHANCE OF RAIN WILL BE ACROSS THE NORTH THRU
15Z...SHIFTING INTO CENTRAL PORTIONS THIS AFTERNOON AND INTO THE
SOUTH TONIGHT.
06Z THRU 15Z...BECOMING GENERALLY MVFR IN CEILINGS AND FOG BY
08Z...WITH OCCASIONAL IFR IN RAIN ACROSS THE NORTH ESPECIALLY ALONG
AND NORTH OF A PKB-CKB-EKN LINE.
AFTER 15Z...CONTINUED MVFR CONDITIONS...ACROSS NORTHERN AND CENTRAL
PORTIONS...ESPECIALLY HTS-CRW-EKN WHERE BEST CHANCE OF RAIN WILL BE.
BECOMING VFR CEILINGS NORTH OF PKB-CKB LINE BY 18Z AND FAR SOUTH
INCLUDING BKW.
AFTER 00Z...BEST CHANCE OF RAIN AND MVFR CONDITIONS MAINLY ACROSS
THE SOUTH HALF ESPECIALLY AFFECTING BKW. ELSEWHERE GENERALLY VFR
CEILINGS.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z SATURDAY...
FORECAST CONFIDENCE: LOW.
ALTERNATE SCENARIOS: TIMING OF FLIGHT CONDITIONS MAY BE HIGHLY
VARIABLE OVERNIGHT AND TOMORROW.
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 08/09/13
UTC 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17
EDT 1HRLY 02 03 04 05 06 07 08 09 10 11 12 13
CRW CONSISTENCY M M M H H H H H H H H H
HTS CONSISTENCY M M M M H H H H H H H H
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY M L M M M M L H H M M L
PKB CONSISTENCY H H H H H H H H H H H H
CKB CONSISTENCY H H H H H H L H H H H M
AFTER 06Z SATURDAY...
IFR POSSIBLE IN ROUNDS OF CONVECTION INTO SATURDAY NIGHT. IN HUMID
AIR IFR CEILINGS COULD EVEN DEVELOP OUTSIDE THE
CONVECTION...ESPECIALLY AT NIGHT AND INTO THE MORNING.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR WVZ005>011-013>020-
024>040-046-047.
OH...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR OHZ066-067-075-076-
083>087.
KY...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR KYZ101>103-105.
VA...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR VAZ003-004.
&&
$$
SYNOPSIS...50/SL
NEAR TERM...50/30
SHORT TERM...SL
LONG TERM...SL
AVIATION...JMV
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
136 AM EDT FRI AUG 9 2013
.SYNOPSIS...
A SLOW MOVING FRONTAL SYSTEM WILL PUSH SOUTHEAST TOWARD THE OHIO
RIVER TONIGHT AND FRIDAY. THE FRONT WILL CONTINUE TO PUSH FARTHER
SOUTH FRIDAY NIGHT INTO SATURDAY AS HIGH PRESSURE AND DRIER AIR
BEGIN TO BUILD INTO THE GREAT LAKES. IN THE MEANTIME...A MOIST
AIRMASS WILL ACCOMPANY THE FRONT WITH THE THREAT OF SHOWERS AND
THUNDERSTORMS...AND LOCALLY HEAVY RAINFALL...EXPECTED THROUGH
FRIDAY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
ARES OF SHOWERS WERE SHOWING TRAINING ECHOS OVER PORTIONS OF
SOUTHEAST INDIANA. UPDATED THE FORECAST TO ACCOUNT FOR THE
CATEGORICAL NATURE OF THE SHOWERS AND THUNDERSTORMS IN THIS AREA
WITH AN EXPECTATION THAT THEY WILL PROGRESS TO THE EAST-SOUTHEAST
OVERNIGHT. TEMPERATURES AND DEWPOINTS WERE BLENDED WITH OBSERVED
VALUES AND WERE ON TRACK AS NEAR AS I COULD SEE.
WILL RELY ON THE RAP AND HRRR MODELS FOR THE NEAR TERM. AS
HELPFUL AS THE MODELS HAVE BEEN IN THE IMMEDIATE NEAR TERM...THE
EVOLUTION OF CONVECTION OVERNIGHT INTO FRIDAY MORNING CONTINUES TO
OSCILLATE WITH EACH SUCCESSIVE RUN...SO WILL DISCUSS THE UNCERTAINTIES
IN THE FORECAST.
EFFECTIVE FRONTAL BOUNDARY MAY HAVE SLID A LITTLE FARTHER SOUTH
THIS EVENING DUE TO RECENT CONVECTION AS SEEN ON MOSAIC RADAR.
THIS MAY PLAY A PART IN WHERE THE BEST COVERAGE OF SHOWERS AND
THUNDERSTORMS WILL OCCUR OVERNIGHT. CONVECTION CURRENTLY OVER THE
REGION HAS SHOWN A DOWNWARD TREND WITH THE DIURNAL CYCLE.
HOWEVER...AN UPTICK IS EXPECTED AGAIN LATER THIS EVENING AND
OVERNIGHT AS AN UPSTREAM MCV OVER SE ILLINOIS TRAVELS EAST THROUGH
THE OHIO VALLEY. ASSOCIATED SUBTLE LOW LEVEL JET/850 MB MOISTURE
TRANSPORT AND A WEAKLY REFLECTED SFC WAVE MAY ALLOW SHOWERS AND
THUNDERSTORMS TO BECOME MORE FOCUSED SOUTH OF THE DAYTON AND
COLUMBUS AREAS...IN OTHER WORDS...ALONG AND SOUTH OF THE OHIO
RIVER BASED ON LATEST MODEL RUNS. BUT GIVEN OSCILLATING SOLUTIONS
FROM RUN TO RUN...AM HESITANT AT THIS TIME TO CUT BUT THE FFA FOR THE
DAYTON AND COLUMBUS AREAS. SO WILL LET THIS HOLD AT THIS TIME BUT
MENTION THAT BETTER COVERAGE MAY BE CLOSER TO THE OHIO RIVER. THE
AIRMASS TONIGHT WILL BE VERY MOIST...PWATS IN EXCESS OF 2
INCHES...AND WARM CLOUD DEPTHS WILL BE FAVORABLE FOR
COLLISION/COALESCENCE PROCESSES. SO THE HEAVY RAIN THREAT WILL
CONTINUE...WITH RAINFALL RATES OF 1 TO 2 INCHES PER HOUR OR
PERHAPS IN SLIGHTLY LESSER TIMES GIVEN FAVORABLE ENVIRONMENT.
LOWS TONIGHT WILL RANGE FROM THE MID 60S FAR NW TO THE LOWER 70S
ALONG AND SOUTH OF THE OHIO RIVER.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM SATURDAY/...
FRONTAL BOUNDARY WILL SLOWLY DROP SOUTHEAST TOWARD THE OHIO RIVER ON
FRIDAY...THEN SOUTH OF THE OHIO RIVER BY SATURDAY MORNING. HAVE
CONTINUED WITH A CHANCE OF SHOWERS AND THUNDERSTORMS...WITH LIKELY
POPS GIVEN TO LOCATIONS ALONG AND SOUTHEAST OF THE FRONT FRIDAY
AFTERNOON DUE TO DIURNAL HEATING AND ANY POSSIBLE DISTURBANCES
ALOFT PASSING BY. AGAIN...THE THREAT OF HEAVY RAIN WILL CONTINUE
AND THIS IS WHY THE 2 SEGMENT OF THE FFA WILL CONTINUE UNTIL 00Z
SATURDAY. INTENSITY AND COVERAGE OF PCPN SHOULD WANE FRIDAY NIGHT
AS THE ATMOSPHERE STABILIZES...AND FRONTAL CONVERGENCE SHIFTS
FARTHER SOUTH. DRIER AIR WILL BEGIN TO BUILD INTO THE NRN ZONES
FRIDAY NIGHT AS HIGH PRESSURE MOVES INTO THE GREAT LAKES REGION.
HIGHS ON FRIDAY WILL BE CLOUD AND PCPN DEPENDENT BUT SHOULD RANGE
FROM THE LOWER TO MID 80S. LOWS FRIDAY NIGHT WILL RANGE FROM THE
LOWER 60S NW TO THE UPPER 60S ALONG AND SOUTH OF THE OHIO RIVER.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
COLD FRONT MAY STILL BE LINGERING IN THE FAR SOUTHERN PART OF THE
FORECAST AREA AT THE BEGINNING OF THE PERIOD BEFORE FINALLY PUSHING
OFF TO THE SOUTH. SO KEPT CHANCE POPS INTO SATURDAY NEAR THIS
BOUNDARY. WENT SLIGHTLY BELOW MOS FOR HIGHS AND THEN LEANED TOWARDS
COOLER NAM GUIDANCE FOR SATURDAY NIGHT LOWS.
HIGH PRESSURE WILL BUILD IN SUNDAY AND MOVE OFF TO THE EAST ON
MONDAY. TEMPERATURES WILL BE NEAR NORMAL DURING THIS TIME FRAME. A
DEVELOPING UPPER TROUGH WILL PUSH A COLD FRONT INTO THE REGION
MONDAY NIGHT INTO TUESDAY. THIS WILL RESULT IN THE NEXT CHANCE OF
SHOWERS AND THUNDERSTORMS. RIDGING WILL RETURN WEDNESDAY AND
THURSDAY AS HIGH PRESSURE SETTLES OVER THE GREAT LAKES BRINGING
ANOTHER COOL AND DRY AIR MASS.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
MVFR VSBYS AND CIGS WILL BE LIKELY THROUGH THE REMAINDER OF
TONIGHT AS A DISTURBANCE BRINGS LIGHT PRECIPITATION TO MOST OF
OUR TERMINALS. THERE COULD BE SOME LOWERING OF CIGS TO IFR AS WE
GET CLOSER TO SUNRISE. MOST PRECIPITATION WILL EXIT THE AREA AFTER
SUNRISE AND OUR LOW CIGS SHOULD SCATTER BY MID MORNING. THIS WILL
LEAVE THE AREA WITH VFR CONDITIONS FROM MID MORNING THROUGH THE
EVENING.
OUTLOOK...THUNDERSTORMS ARE POSSIBLE MONDAY NIGHT INTO TUESDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...FLASH FLOOD WATCH UNTIL 8 AM EDT THIS MORNING FOR OHZ045-046-
051>056-060>065-070>072.
FLASH FLOOD WATCH THROUGH THIS EVENING FOR OHZ073-074-077>082-
088.
KY...FLASH FLOOD WATCH THROUGH THIS EVENING FOR KYZ089>100.
IN...FLASH FLOOD WATCH UNTIL 8 AM EDT THIS MORNING FOR INZ050-058-
059-066-073-074.
FLASH FLOOD WATCH THROUGH THIS EVENING FOR INZ075-080.
&&
$$
SYNOPSIS...HICKMAN
NEAR TERM...FRANKS/HICKMAN
SHORT TERM...HICKMAN
LONG TERM...
AVIATION...LATTO
AREA FORECAST DISCUSSION
NWS NORMAN OK
1210 AM CDT FRI AUG 9 2013
.AVIATION... WIDESPREAD SHOWERS AND THUNDERSTORMS WILL CONTINUE
EARLY IN THE PERIOD WITH PREVAILING OR TEMPO GROUPS AT ALL BUT FAR
SRN SITES. POST FRONTAL MVFR CIGS MAY SPREAD THROUGH NRN AND INTO
CNTRL OK THROUGH THE EARLY MORNING HOURS THEN BECOMING VFR DURING
THE AFTN.
&&
.PREV DISCUSSION... /ISSUED 647 PM CDT THU AUG 8 2013/
.AVIATION...
SEVERAL SMALL CLUSTERS OF STORMS HAVE FORMED DURING THE
LATE AFTERNOON AND EARLY EVENING IN SOUTHWEST OK AND
WESTERN NORTH TEXAS. RECENT HRRR RUNS SUGGEST BETTER ORGANIZATION
MAY OCCUR AS PRECIP/STORMS MOVE NORTHEAST THIS EVENING. IF THIS
OCCURS MOST OF THE PRECIP MAY CLEAR SOUTHWEST OK AND NORTH TEXAS
BY THE LATE EVENING. ADDITIONAL STORMS MAY IMPACT WESTERN AND
NORTHERN OKLAHOMA LATE THIS EVENING AND OVERNIGHT. MVFR CEILINGS
AND VISIBILITIES MAY OCCUR WITH THE STRONGER STORMS THIS
EVENING AND OVERNIGHT.
&&
.PREV DISCUSSION... /ISSUED 328 PM CDT THU AUG 8 2013/
DISCUSSION...
EXTENSIVE CLOUD COVER HELD DOWN TEMPERATURES FOR MOST OF THE
DAY...GREATLY LIMITING INSTABILITY AND DELAYING THE FORMATION OF
SHOWERS/THUNDERSTORMS. THE CLOUD COVER HAS DIMINISHED ACROSS THE
WESTERN HALF OF OUR FORECAST AREA...ALLOWING RAPID WARMING AND
DESTABILIZATION. A FEW THUNDERSTORMS FORMED QUICKLY WITHIN THE
PAST HOUR JUST OUTSIDE OUR FORECAST AREA IN TEXAS. ADDITIONAL
DEVELOPMENT IS LIKELY...BUT THE EXACT LOCATION IS STILL UNCLEAR.
THERE IS ALSO SOME UNCERTAINTY REGARDING THE EVENTUAL FORMATION OF
ANOTHER MCS OVERNIGHT...BUT IT STILL SEEMS MOST PROBABLE THAT
NORTHERN OKLAHOMA WILL BE THE TARGET OF ANY CONVECTIVE SYSTEMS
THAT MAY DEVELOP TONIGHT. AS A RESULT...THE EXPECTED RAINFALL
COULD CAUSE FLOODING PROBLEMS...AND A FLOOD WATCH HAS BEEN ISSUED
FOR TONIGHT THROUGH MIDDAY TOMORROW.
IT APPEARS THAT THE SUPPORT FOR CONTINUED CONVECTION WILL DIMINISH
TOMORROW...CAUSING LOWER CHANCES OF RAIN AND STORMS...LESS
QPF...AND LESS CHANCE OF ADDITIONAL FLOODING. RIVERS MAY CONTINUE
TO FLOOD...BUT OTHERWISE THE RISK IS MUCH LOWER TOMORROW AFTERNOON
INTO THE WEEKEND.
THE OVERALL PATTERN REMAINS FAVORABLE FOR OCCASIONAL SHOWERS AND
THUNDERSTORMS THROUGH THE PERIOD...WITH TEMPERATURES RUNNING
FAIRLY CLOSE TO THE SEASONAL AVERAGES.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 73 90 71 90 / 60 30 20 10
HOBART OK 73 91 69 92 / 60 20 20 10
WICHITA FALLS TX 75 98 73 96 / 40 20 20 10
GAGE OK 68 80 65 87 / 60 20 10 10
PONCA CITY OK 71 85 68 85 / 70 30 20 10
DURANT OK 74 100 74 97 / 30 20 20 20
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...FLOOD WATCH FROM 10 PM CDT THIS EVENING THROUGH FRIDAY AFTERNOON
FOR OKZ004>008-010>013.
TX...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
543 AM EDT FRI AUG 9 2013
.SYNOPSIS...
THE WARM MOIST AIR CONTINUES TO BRING SHOWERS TO THE REGION. A
COLD FRONT WILL BEGIN TO PUSH DRIER AIR INTO PENNSYLVANIA LATER
THIS AFTERNOON INTO EARLY SATURDAY. THE COLD FRONT WILL LIKELY
TRIGGER THUNDERSTORMS LATER TODAY. MUCH DRIER WILL MOVE OVER THE
ENTIRE REGION SATURDAY. A TROUGH BUILDS OVER NORTHEASTERN NORTH
AMERICA WHICH SHOULD KEEP US IN GENERALLY NORTHWEST FLOW MOST OF
THE NEXT 3-8 DAYS ENSURING WEAK FRONTAL PASSAGES AND GENERALLY LOW
HUMIDITY AND LOW PROBABILITY OF SIGNIFICANT RAINFALL.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
RADAR CONTINUES TO SHOW SHOWERS AND EMBEDDED THUNDERSTORMS MOVING
OVER THE MOISTURE BOUNDARY OVER CENTRAL PENNSYLVANIA BEST DEFINED
IN THE LOW-LEVEL THETA-E GRADIENT. THE LARGER SCALE THETA GRADIENT
IS IMPLYING THE FRONTAL PUSH TO OUR NORTHWEST IS NOT INTO
NORTHWESTERNMOST PA. SHOWERS WILL BECOME MORE NUMEROUS IN THE WEST
OVER THE NEXT FEW HOURS.
THE WARM MOIST AIR AND ABOVE NORMAL PW HAVE KEPT THE MORNING LOWS
MAINLY IN THE UPPER 60S AND 70S. GOING TO BE A WARM MOIST DAY OVER
CENTRAL AND SOUTHEASTERN AREAS.
THE PROBABILITY OF RAIN SHOULD DROP OFF FAST IN THE NW THIS
AFTERNOON. MOST FORECASTS FROM SREF TO HRRR IMPLY BY MID- LATE
AFTERNOON THE THREAT OF RAIN IN NW PASSES. EVEN CENTRAL AREAS
NOW APPEAR TO HAVE A GOOD SHOW OF NICE LATER AFTERNOON AND EARLY
EVENING AS THE DRIER AIR SLIDES TO THE SOUTHEAST.
SHOWERS AND STORMS WITH LOCALLY HEAVY RAIN FROM A FEW STRONGER
CELLS WILL LINGER LONGER IN THE SOUTHEAST.
TEMPS MAINLY 70S IN NEW TO MID-UPPER 80S SOUTHEAST. WINDS SHOULD
BECOME MORE WESTERLY IN NW PA THIS AFTERNOON.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
THE MODELS ALL SHOW LOWER PW AIR FILTERING INTO PA FAST. DROPPED
ALL POPS IN CENTRAL AND NORTHERN AREAS BEFORE 8 PM. LOWERED POPS
FAST IN THE SOUTHEAST WITH NO RAIN OF NOTE MUCH AFTER MIDNIGHT
THEN THE DRYING OUT BEGINS. ENSEMBLES IMPLY BY 0300 UTC ALL THREAT
OF RAIN IS TO OUR SOUTH AND EAST.
SATURDAY SHOULD BE MOSTLY SUNNY WITH TEMPERATURES NEAR NORMAL. THE
850 HPA TEMPS DO NOT DROP BELOW NORMAL UNTIL AFTER THIS PERIOD.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
THE COMING WEEK SHOULD BE RELATIVELY DRY AS MOST MODELS AT THIS
TIME AND ENSEMBLE FORECAST SYSTEMS (EFS) SHOW PW VALUES GENERALLY
NORMAL TO BELOW NORMAL. NOT A GOOD PATTERN FOR RAIN LET ALONE
HEAVY RAINFALL.
A MEAN TROUGH WILL DOMINATE THE EASTERN UNITED STATES WELL INTO
NEXT WEEK. SOME PIN WHEELING WAVES IMPLY CHANCES OF SCATTERED
SHOWERS SHOULD WE GET A ENOUGH MOISTURE OR INSTABILITY AHEAD OF
SOME OF THE WAVES. AT THIS TIME WE FLIRT WITH SOME MOISTURE TUES-WED
FOR SLIGHT INCREASE SHOWERS...NOT VERY IMPRESSIVE.
THE 850 HPA TEMPS ARE NORMAL TO SOME PERIODS WHERE THEY FALL
SLIGHTLY BELOW NORMAL. THE PW STAYS NORMAL TO BELOW NORMAL TOO.
THE PIN WHEELING TROUGHS OF COURSE PUSH THE WEAK SURGES OF COOLER
AND DRIER AIR IN.
THUS A GENERALLY COOL DRY WEEK IS CURRENTLY FORECAST.
&&
.AVIATION /10Z FRIDAY THROUGH TUESDAY/...
WIDE RANGE IN CONDITIONS THE LAST FEW HOURS.
MADE SOME ADJUSTMENTS TO THE 09Z TAFS.
SOME HEAVY SHOWERS DEVELOPING JUST EAST OF UNV NOW.
MORE WIDESPRED SHOWERS NOW TO THE WEST WITH THE FRONT.
EXPECT CONDITIONS TO IMPROVE FROM WEST TO EAST THIS AFT...
AS A WEAK COLD FRONT MOVES ACROSS THE AREA. DEWPOINTS ON
THE HIGH SIDE...BUT WINDS ALOFT NOT REAL STRONG FOR
SEVERE STORMS.
INTERESTING THING ABOUT DEWPOINTS. MAV GUIDANCE FCST A
DEWPOINT OF 75 IN MDT YESTERDAY. DEWPOINTS CAME UP HIGH...
BUT NOT THAT HIGH.
EXPECT SHOWERS AND STORMS TO TAPER OFF ACROSS THE FAR
SE ON SAT.
WEAK COLD ADVECTION TODAY INTO SAT...NOT A LOT OF COLD
ADVECTION BEFORE THE MIDDLE OF NEXT WEEK.
MAIN CONCERN WILL BE IF WE WILL GET FOG SAT AM...BEHIND
THE FRONT...AS TEMPS FALL TO NEAR THE CROSS OVER VALUE.
LOOKS LIKE IT WILL BE MID WEEK...BEFORE ANY REAL DEEP
COLD AIR WORKS INTO CENTRAL PA.
OUTLOOK...
SAT...MVFR/IFR EARLY WITH PATCHY FOG...THEN VFR.
SUN-MON...GENERALLY VFR...BUT POSSIBLE AM RESTRICTIONS IN FOG.
TUE...VFR...BUT POSSIBLE RESTRICTIONS IN SHRA/TSRA WITH NEXT
COLD FRONT.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...GRUMM
NEAR TERM...GRUMM
SHORT TERM...GRUMM
LONG TERM...GRUMM/GARTNER
AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
510 AM EDT FRI AUG 9 2013
.SYNOPSIS...
THE WARM MOIST AIR CONTINUES TO BRING SHOWERS TO THE REGION. A
COLD FRONT WILL BEGIN TO PUSH DRIER AIR INTO PENNSYLVANIA LATER
THIS AFTERNOON INTO EARLY SATURDAY. THE COLD FRONT WILL LIKELY
TRIGGER THUNDERSTORMS LATER TODAY. MUCH DRIER WILL MOVE OVER THE
ENTIRE REGION SATURDAY. A TROUGH BUILDS OVER NORTHEASTERN NORTH
AMERICA WHICH SHOULD KEEP US IN GENERALLY NORTHWEST FLOW MOST OF
THE NEXT 3-8 DAYS ENSURING WEAK FRONTAL PASSAGES AND GENERALLY LOW
HUMIDITY AND LOW PROBABILITY OF SIGNIFICANT RAINFALL.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
RADAR CONTINUES TO SHOW SHOWERS AND EMBEDDED THUNDERSTORMS MOVING
OVER THE MOISTURE BOUNDARY OVER CENTRAL PENNSYLVANIA BEST DEFINED
IN THE LOW-LEVEL THETA-E GRADIENT. THE LARGER SCALE THETA GRADIENT
IS IMPLYING THE FRONTAL PUSH TO OUR NORTHWEST IS NOT INTO
NORTHWESTERNMOST PA. SHOWERS WILL BECOME MORE NUMEROUS IN THE WEST
OVER THE NEXT FEW HOURS.
THE WARM MOIST AIR AND ABOVE NORMAL PW HAVE KEPT THE MORNING LOWS
MAINLY IN THE UPPER 60S AND 70S. GOING TO BE A WARM MOIST DAY OVER
CENTRAL AND SOUTHEASTERN AREAS.
THE PROBABILITY OF RAIN SHOULD DROP OFF FAST IN THE NW THIS
AFTERNOON. MOST FORECASTS FROM SREF TO HRRR IMPLY BY MID- LATE
AFTERNOON THE THREAT OF RAIN IN NW PASSES. EVEN CENTRAL AREAS
NOW APPEAR TO HAVE A GOOD SHOW OF NICE LATER AFTERNOON AND EARLY
EVENING AS THE DRIER AIR SLIDES TO THE SOUTHEAST.
SHOWERS AND STORMS WITH LOCALLY HEAVY RAIN FROM A FEW STRONGER
CELLS WILL LINGER LONGER IN THE SOUTHEAST.
TEMPS MAINLY 70S IN NEW TO MID-UPPER 80S SOUTHEAST. WINDS SHOULD
BECOME MORE WESTERLY IN NW PA THIS AFTERNOON.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
THE MODELS ALL SHOW LOWER PW AIR FILTERING INTO PA FAST. DROPPED
ALL POPS IN CENTRAL AND NORTHERN AREAS BEFORE 8 PM. LOWERED POPS
FAST IN THE SOUTHEAST WITH NO RAIN OF NOTE MUCH AFTER MIDNIGHT
THEN THE DRYING OUT BEGINS. ENSEMBLES IMPLY BY 0300 UTC ALL THREAT
OF RAIN IS TO OUR SOUTH AND EAST.
SATURDAY SHOULD BE MOSTLY SUNNY WITH TEMPERATURES NEAR NORMAL. THE
850 HPA TEMPS DO NOT DROP BELOW NORMAL UNTIL AFTER THIS PERIOD.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
THE COMING WEEK SHOULD BE RELATIVELY DRY AS MOST MODELS AT THIS
TIME AND ENSEMBLE FORECAST SYSTEMS (EFS) SHOW PW VALUES GENERALLY
NORMAL TO BELOW NORMAL. NOT A GOOD PATTERN FOR RAIN LET ALONE
HEAVY RAINFALL.
A MEAN TROUGH WILL DOMINATE THE EASTERN UNITED STATES WELL INTO
NEXT WEEK. SOME PIN WHEELING WAVES IMPLY CHANCES OF SCATTERED
SHOWERS SHOULD WE GET A ENOUGH MOISTURE OR INSTABILITY AHEAD OF
SOME OF THE WAVES. AT THIS TIME WE FLIRT WITH SOME MOISTURE TUES-WED
FOR SLIGHT INCREASE SHOWERS...NOT VERY IMPRESSIVE.
THE 850 HPA TEMPS ARE NORMAL TO SOME PERIODS WHERE THEY FALL
SLIGHTLY BELOW NORMAL. THE PW STAYS NORMAL TO BELOW NORMAL TOO.
THE PIN WHEELING TROUGHS OF COURSE PUSH THE WEAK SURGES OF COOLER
AND DRIER AIR IN.
THUS A GENERALLY COOL DRY WEEK IS CURRENTLY FORECAST.
&&
.AVIATION /09Z FRIDAY THROUGH TUESDAY/...
A FEW SHOWERS ON THE RADAR...MAINLY SE...WHERE WINDS ARE
MORE FROM THE SE.
WIDE RANGE WITH CIGS WILL CONTINUE THIS MORNING. VISIBILITIES
NOT BAD FOR THE MOST PART.
EXPECT CONDITIONS TO IMPROVE FROM WEST TO EAST THIS AFT...
AS WEAK COLD FRONT MOVES ACROSS THE AREA. DEWPOINTS ON
THE HIGH SIDE...BUT WINDS ALOFT NOT REAL STRONG FOR
SEVERE STORMS.
EXPECT SHOWERS AND STORMS TO TAPER OFF ACROSS THE FAR
SE ON SAT.
WEAK COLD ADVECTION TODAY INTO SAT...NOT A LOT OF COLD
ADVECTION BEFORE THE MIDDLE OF NEXT WEEK.
MAIN CONCERN WILL BE IF WE WILL GET FOG SAT AM...BEHIND
THE FRONT...AS TEMPS FALL TO NEAR THE CROSS OVER VALUE.
LOOKS LIKE IT WILL BE MID WEEK...BEFORE ANY REAL DEEP
COLD AIR WORKS INTO CENTRAL PA.
OUTLOOK...
SAT...MVFR/IFR EARLY WITH PATCHY FOG...THEN VFR.
SUN-MON...GENERALLY VFR...BUT POSSIBLE AM RESTRICTIONS IN FOG.
TUE...VFR...BUT POSSIBLE RESTRICTIONS IN SHRA/TSRA WITH NEXT
COLD FRONT.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...GRUMM
NEAR TERM...GRUMM
SHORT TERM...GRUMM
LONG TERM...GRUMM/GARTNER
AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
313 AM CDT FRI AUG 9 2013
DISCUSSION...
PATTERN THROUGH SUNDAY IS NOT CHANGING THAT MUCH. W-E RIDGE ALOFT
WILL REMAIN ANCHORED ACROSS THE DEEP SOUTH. FRONTAL BOUNDARY WILL
REMAIN TO THE NORTH OF TN. HOWEVER...THIS BOUNDARY WILL MAKE SOME
SOUTHWARD PROGRESS AND LATE FRI NIGHT INTO SATURDAY...SURFACE
CONVERGENCE WILL COUPLE WITH DIVERGENCE ALOFT TO PROVIDE AN
INCREASING CHANCE OF CONVECTION. MOISTURE PARAMETERS PICK UP ON IT
AS WELL WITH THE DEEPEST MOISTURE...BETWEEN NOW AND
SUNDAY...OCCURRING LATE FRI NT AND INTO SATURDAY.
FOR TODAY...LATEST HRRR SHOWING A LULL IN ANY CONVECTION UNTIL
AROUND 19Z OR SO. THE ACTIVITY ACROSS SOUTHERN KY SHOULD LIFT ON OFF
TO THE ENE...BUT WESTERN AND NW AREAS MAY SEE SOME CONVECTION
MOVE IN FROM THE WEST LATER THIS MORNING. HRRR EXPECTS THE
CONVECTION TO WEAKEN THOUGH. OTW...CAP EROSION IS STILL APPARENT
THIS AFTERNOON WITH CAPES ON THE INCREASE. THUS...LOOK FOR SCT
ACTIVITY THIS AFTERNOON. AGAIN...POP CHANCES TO INCREASE LATE
TONIGHT AND ON SATURDAY.
ON SUNDAY...BOUNDARY SHOWS A DECREASE IN FORCING BUT PROXIMITY
INFLUENCES ARE GREATER WITH THE STATIONARY BOUNDARY RIGHT OVER US.
THUS...APPRECIABLE 40-50 POPS WILL CONTINUE.
FOR THE NEAR TERM TEMPS...KEEPING IN MIND THAT THE MAV GUIDANCE HAS
PERFORMED RATHER MISERABLY ON HIGH TEMPS RECENTLY...WILL AGREE TO
BELIEVE IN A CONTINUATION OF THAT FORTUITOUS TREND. WILL UNDERCUT
EACH DAY BY 3 DEG OR SO. WILL GO NEAR TO SLIGHTLY BELOW ON MINS.
IN THE EXT FCST...UPPER TROUGHING PATTERN OVER THE EASTERN U.S. WILL
BEGIN TO EVOLVE. PVA UPSTREAM WILL CATCH UP WITH WEAK SFC BOUNDARIES
AND INTENSIFY A W-E COLD FRONT ALONG THE OHIO RIVER BY MID WEEK.
THIS FEATURE WILL DROP SLOWLY SOUTHWARD WITH A FROPA OCCURRING WED
OR THU. IN ADVANCE OF THE FROPA..CONVECTION CHANCES WILL CONTINUE
WITH THE GREATEST PROBABILITIES OCCURRING TUES AND WED. BEYOND THE
SCOPE OF THE 7 DAY EXT...PERHAPS A DRIER AND SLIGHTLY COOLER AIRMASS
WILL SETTLE IN. 18Z FRI TEMPS FROM A VARIETY OF MODELS ALL SUGGEST A
COOLER TREND...A PRE FALL TASTE OF DRIER PERHAPS? WE WILL SEE.
VERSUS THE EXT TEMPS...850 MB TEMPS AND A SFC 18Z AND 12Z REVIEW ALL
SUGGESTS THAT THE MEX NUMBERS FOR HIGH TEMPS ARE TOO HIGH. WILL
UNDERCUT BY A FEW DEGREES THROUGHOUT THE PERIOD. MINS LOOK GENERALLY
OK.
.PRELIMINARY POINT TEMPS/POPS...
NASHVILLE 88 71 88 71 / 60 60 60 40
CLARKSVILLE 88 69 87 68 / 60 60 60 40
CROSSVILLE 83 66 81 67 / 60 50 70 40
COLUMBIA 89 71 89 72 / 40 50 60 40
LAWRENCEBURG 88 71 90 71 / 40 40 60 40
WAVERLY 88 69 88 70 / 60 60 60 50
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
21
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1158 PM CDT THU AUG 8 2013
.UPDATE...FOR 06Z AVIATION.
&&
.AVIATION...06Z TAF DISCUSSION.
WITH THE CURRENT TRENDS AND WHAT SEEMS TO BE A STABLE YET MOIST
ATMOSPHERE...HAVE PUSHED PREVAILING RAIN AND VCTS BACK UNTIL 12Z.
THIS DOES NOT NEGATE LOWER FLIGHT CATEGORIES THOUGH. IFR TO MVFR
CONDITIONS WILL LIKELY SETTLE INTO MIDDLE TENNESSEE BY DAYBREAK.
THE ONE FACTOR THAT MAY STIFLE STRATUS/FOG DEVELOPMENT IS THE
CURRENT HIGH CLOUD SHIELD. WILL GO AHEAD AND PREVAIL THESE CLOUDS
AS SATELLITE SHOWS SOME CLEARING IS POSSIBLE WITHIN THE NEXT 3
HOURS. WINDS WILL BE LIGHT...AND VEER TO THE SOUTHWEST BY FRIDAY
AFTERNOON.
UNGER
&&
.PREV DISCUSSION... /ISSUED 1005 PM CDT THU AUG 8 2013/
UPDATE...ACTIVITY OVER WEST TENNESSEE IS DIMINISHING RAPIDLY AS
OUR QUIET WEATHER CONTINUES THIS EVENING. SURFACE FRONT WILL
INCH CLOSER TO MIDDLE TENNESSEE OVERNIGHT. HRRR SHOWS VERY LITTLE
PRECIPITATION MOVING ACROSS MIDDLE TENNESSEE OVER THE NEXT SEVERAL
HOURS, ALTHOUGH THE LATEST NAM SHOWS AN AXIS OF 850 MB MOISTURE
AND POSITIVE OMEGA PUSHING THROUGH THE MID STATE AFTER 06Z. GIVEN
THAT THE ATMOSPHERE REMAINS VERY MOIST AND MODESTLY UNSTABLE, AND
THE NOCTURNAL STORMS THAT DEVELOPED LAST NIGHT, AM LOATHE TO LOWER
POP`S THIS TIME. SO WILL LEAVE THE CURRENT FORECAST ALONE.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
27
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
403 AM EDT FRI AUG 9 2013
.SYNOPSIS...
A SLOW MOVING FRONT IS EXPECTED TO MOVE SOUTHEAST THROUGH OUR AREA
THIS WEEKEND. HIGH PRESSURE OVER THE UPPER MIDWEST SHIFTS
SOUTHEAST THROUGH THE MID ATLANTIC BY THE END OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 330 AM EDT FRIDAY...
RADARS QUIET THIS MORNING WITH ONLY ONE LONE SHOWER EXITING NRN
GREENBRIER COUNTY WITH MOST CONVECTION CENTERED WITH AND AHEAD OF A
SHORTWAVE AROUND CINCINNATI. THE 12Z ECMWF/00Z GFS ZERO IN ON THIS
SHORTWAVE AND PRECIP AND MAINLY SEE IT SHIFTING ENE INTO NRN WV
LATER THIS MORNING WITH A FEW SHOWERS MAKING ITS WAY INTO SE WV. FOR
EARLY TODAY WILL BE DEALING WITH AREAS OF FOG...LOCALLY DENSE AS IT
HAS CLEARED OUT SOME ASIDE FROM SOME HIGH CLOUDS. THIS FOG WILL BE
GOING AWAY AROUND 900 AM.
LOOKING AT WSW FLOW BACKING DURING THE DAY AND AFTER MIDDAY MODELS
SHOWING SOME LOW LVL CONVERGENCE ALONG THE BLUE RIDGE WITH A
PREFRONTAL TROUGH...WITH UPPER SUPPORT AND MAIN FRONT STAYING ACROSS
THE OHIO VALLEY INTO THE MID ATLANTIC. THINK COVERAGE WILL AGAIN
BECOME SCATTERED TO NUMEROUS OVER THE MOUNTAINS THEN SHIFT TO THE
PIEDMONT AS FLOW BACKS. WITH BETTER MIXING AND MORE SUNSHINE...THE
INSTABILITY AND CONVECTIVE TEMPS SUPPORT MORE THUNDER. STORMS WILL
BE HEAVY RAIN PRODUCERS AND MEAN FLOW SHOWING STORM MOVEMENT OF 10
TO 20 MPH. OVERALL THREAT FOR SVR THUNDERSTORMS AND FLASH FLOODING
REMAINS ISOLATED...SO NO WATCHES FOR FLASH FLOODING EXPECTED AND
WILL CONTINUE TO MENTION HEAVY RAIN...ISOLATED SVR IN THE HWO.
AS WE HEAD INTO LATE AFTERNOON AND EARLY EVENING THE LOW LVL FLOW
VEERS TO THE WEST AND THE GFS ESPECIALLY DRIES THE LEE SIDE OF THE
MOUNTAINS OUT WHILE HOLDING ONTO CONVECTION IN THE PIEDMONT...SO
WILL BE LEANING TOWARD LOWER POPS IN THE NEW RIVER VALLEY/FOOTHILLS
BY DUSK WHILE KEEPING THE WRN SLOPES AND PIEDMONT WITH HIGHER POPS.
OUR LOCAL WRF AND HRRR SHOWING THIS TO BE THE CASE AS WELL.
THINK WILL SEE SHOWERS AND STORMS SUBSIDE AGAIN BY LATE
EVENING/MIDNIGHT ESPECIALLY IN THE EAST WITH LOSS OF HEATING BUT
EXPECT THE THREAT OF SHOWERS TO REMAIN OVER THE WV/FAR SW VA MTNS
AHEAD OF THE FRONT AND CLOSER TO THE UPPER LEVEL SUPPORT.
FOR HIGHS TODAY WENT CLOSE TO THE ECMWF MOS AS THE GFS SEEMS TO WARM
AND NAM TOO COOL. LOOKING AT WARMER TEMPS WITH MORE SUN AND MIXING
BEFORE STORMS SET IN...WITH LOWER 80S WEST TO MID 80S TO NEAR 90
EAST.
TONIGHT REMAINS MUGGY WITH LOWS GENERALLY IN THE MID TO UPPER 60S
MOUNTAINS INTO THE LOWER 70S EAST.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY NIGHT/...
AS OF 400 AM EDT FRIDAY...
SHOWERS AND THUNDERSTORMS WILL REMAIN IN THE FORECAST THIS WEEKEND
INTO THE NEXT WORKWEEK AS A COLD FRONT MAKES ITS WAY ACROSS OUR
REGION. IN STICKING CLOSE WITH THE ECMWF MODEL SOLUTION...EXPECT TO
START SATURDAY OFF WITH THE COLD FRONT SITUATED NEAR THE INTERSTATE
81 CORRIDOR...WITH THE FRONT DRIFTING SLOWLY SOUTHWARD THROUGH THE
DAY...PERHAPS AIDED IN ITS PUSH BY OUTFLOW FROM AFTERNOON/EVENING
SHOWERS AND THUNDERSTORMS. BY SUNDAY MORNING...THE FRONT IS EXPECTED
TO ADVANCE INTO NORTH CAROLINA...WHERE IT WILL STALL AND BEGIN TO
WASH OUT ON MONDAY AS ANOTHER COLD FRONT APPROACHES FROM THE UPPER
MIDWEST.
DESPITE THE PASSAGE OF THE FRONT...WILL STILL SEE ABUNDANT LOW LEVEL
MOISTURE ACROSS OUR AREA AS DRIER AIR LINGERS TO OUR NORTH. MINOR
DISTURBANCES ALOFT WILL CONTINUALLY PASS ALONG THE FRONT FROM THE
WEST DURING THE WEEKEND...AND WILL TRIGGER ROUNDS OF SHOWERS AND
THUNDERSTORMS...MAINLY EACH AFTERNOON AND EVENING WHEN ENHANCED BY
DAYTIME HEATING. AS IN PREVIOUS NIGHTS...BELIEVE WE WILL SEE A
DRASTIC REDUCTION IN THE AMOUNT OF SHOWER ACTIVITY AFTER
SUNSET...ALTHOUGH CANNOT RULE A FEW SHOWERS DURING THE OVERNIGHTS.
WILL ALSO POINT OUT THE POSSIBILITY OF A FEW STRONG STORMS ON
SATURDAY AND SUNDAY...MORE SO SOUTH OF INTERSTATE 81. WHILE STRONG
THUNDERSTORM WINDS AND FREQUENT LIGHTNING WILL BE CONCERNS...THE
GREATEST CONCERN WILL BE FROM LOCALLY HEAVY RAIN AND THE POSSIBILITY
OF FLASH FLOODING. ANY FLOODING SHOULD REMAIN LOCAL IN SCALE...BUT
MAY DEVELOP QUICKLY IN STORMS WITH HIGH RAINFALL RATES...AND
ESPECIALLY IN LOCATIONS WITH SATURATED SOILS FROM RECENT HEAVY RAIN.
&&
.LONG TERM /TUESDAY THROUGH THURSDAY/...
AS OF 350 PM EDT THURSDAY...
A COLD FRONT ASSOCIATED WITH AN IMPRESSIVE CHUNK OF CHILLY AIR FOR
THIS TIME OF YEAR WILL ALLOW SHOWERS AND STORMS TO CROP UP AGAIN ON
TUESDAY. ONCE THIS BOUNDARY PASSES...H85 TEMPS MAY FALL AS COLD AS
+9C BY THE MIDDLE OF NEXT WEEK. THE CHILLY AIR ALOFT WILL PRODUCE
EXTENSIVE CLOUDS AND PROBABLY WIDELY SCATTERED SHOWERS. BY THE END
OF NEXT WEEK...THIS FRONT BEGINS TO JOG NORTH AGAIN AND WARMER AIR
RETURNS.
&&
.AVIATION /08Z FRIDAY THROUGH TUESDAY/...
AS OF 140 AM EDT FRIDAY...
DEALING WITH A BIT OF FOG AND LOW CLOUDS EARLY THIS MORNING
ESPECIALLY AT ROA/LYH/BCB...WHERE IT RAINED. SEEMS THERE ARE
BREAKS IN THE LOWER CLOUDS TO ALLOW FOR FOG AND LOW STRATUS...AND
CONFIDENCE HIGH ENOUGH TO FORECAST IFR OR WORSE AT ALL TAF SITES
BUT BLF WHERE THEY SHOULD DROP TO MVFR. ANY SHOWERS SHOULD STAY
MAINLY NORTH OF LWB/BLF BUT KEPT VCSH AT LWB GIVEN PROXIMITY OF
UPPER SHORTWAVE.
FOG/LOW CLOUD SHOULD CLEAR OUT BY MID MORNING BUT WILL BE BKN AT
MVFR/VFR THRU THE DAY. WITH GOOD MIXING FROM A WSW WIND SHOULD SEE
MORE SUNSHINE BY THE AFTERNOON AND MODELS ADVERTISING GOOD THREAT
OF SHOWERS AND STORMS. HAVE ALLOWED FOR VCTS AT ALL TAF SITES WITH
LIGHT TO MODERATE SHOWERS. HOWEVER...WILL KEEP VSBYS/CIGS VFR.
THE CONVECTION WEAKENS/ENDS AROUND 00Z SAT EXCEPT LINGERING
SHOWERS ACROSS THE LWB CORRIDOR DUE TO ANOTHER SHORTWAVE PUSHING
ACROSS NRN WV.
APPEARS FOG AND LOWER STRATUS COULD BE AN ISSUE AGAIN FRIDAY
NIGHT.
THE FRONT SHIFTS SLOWLY SOUTHEAST THRU THE WEEKEND AND KEEPS THE
THREAT OF SHOWERS/STORMS AROUND. THE FRONT MAY SLIP SOUTH OF THE
AREA BY MONDAY INTO TUESDAY WITH STILL SOME THREAT OF SHOWERS OVER
THE SRN CWA FROM DAN-BCB-BLF.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...WP
NEAR TERM...WP
SHORT TERM...NF
LONG TERM...KM
AVIATION...WP
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
1200 PM EDT FRI AUG 9 2013
.SYNOPSIS...
A COLD FRONT WILL SLOWLY APPROACH FROM THE WEST THIS AFTERNOON AND
MOVE THROUGH THE REGION BY EARLY SATURDAY. THIS FRONT WILL THEN
STALL TO OUR SOUTH THROUGH MONDAY. A FEW WAVES OF LOW PRESSURE MAY
MOVE ALONG THIS BOUNDARY FOR THE EARLY PART OF THE WEEK. ANOTHER
COLD FRONT WILL CROSS THE REGION FROM THE WEST AROUND TUESDAY,
FOLLOWED BY AN AREA OF HIGH PRESSURE FOR WEDNESDAY AND THURSDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SPC HRW WRF-ARW IS VERIFYING THE BEST OF THE MESOSCALE MODELS THIS
MORNING AND WAS USED AS A BACK END TIMING OF HIGHER POPS. ON THE
FRONT SIDE, THE HRRR GETS VIGOROUS RATHER QUICKLY WHICH GIVEN WE
ARE NEARING THE CONVECTIVE TEMP CAN NOT BE DISCOUNTED. THE
OPERATIVE WORD FROM HERE ON OUT IS THAT ALL OF THE MESOSCALE MODEL
PROGRESSIONS EVEN IF NOT GEOGRAPHICALLY CORRECT ARE OF DECENT
MOVEMENT. THIS WOULD REDUCE THE FLASH FLOOD THREAT IN PLACES THAT
WERE NOT DOUSED THIS MORNING. OTHERWISE, NO BIG CHANGES TO THE
CONVECTIVE CONCERNS. THE MID LEVEL LAPSE RATES ARE NOT IMPRESSIVE
AND WARMER AIR CONTINUES TO MOVE IN AT 700MB AND 500MB. THERE MAY
BE A WINDOW SERN CWA BECAUSE OF THE CAPPING WHERE THE INITIAL
RELEASE MIGHT PRODUCE VIGOROUS ENOUGH UPDRAFTS TO CAUSE
THUNDERSTORMS TO POSSIBLY REACH SEVERE LIMITS. LESS LIKELY NORTH
AND WEST OF I95 WHERE CONVECTION SHOULD BE RAMPING UPWARD PRETTY
QUICKLY.
BASED ON CURRENT TEMPS AND SUNSHINE, WE NUDGED MAX TEMPS UP
SLIGHTLY AGAIN SERN PART OF OUR CWA.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SATURDAY/...
THE FRONT WILL CONTINUE CROSSING THE AREA TONIGHT. POPS DECREASE
FROM NORTH TO SOUTH AND THE NIGHT PROGRESSES. WINDS SHIFT TO WRLY
THEN NWRLY OVERNIGHT AND DRIER AIR BEGINS TO ARRIVE OVER THE AREA.
IT MAY TAKE UNTIL AFTER DAWN SAT TO BEGIN MIXING THE DRIER AIR DOWN.
OVERNIGHT LOW TEMPS TONIGHT WILL RANGE FROM THE LOW 60S ACROSS THE
NORTH TO THE LOW 70S OVER THE SOUTH...WHERE THE FRONT WILL CROSS
LATE.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
AT THE START OF THE EXTENDD PD, THE AFOREMENTIONED CDFNT WILL BE
OFF THE CST AND ALL OF THE MDL GUID IS IN REASONABLE AGREEMENT
THAT SAT SHOULD BE MOSTLY IF NOT ALL DRY. IF THERE IS TO BE ANY
LINGERING PRECIP, IT WILL BE EARLY AND ACRS THE S. FOR NOW, WILL
JUST KEEP SOME VERY LOW POPS ACRS SRN AREAS EARLY AND THIS COULD
END UP BEING OVERDONE.
HIGH PRESSURE THEN BUILD IN BEHIND THE FRONT, WHICH WILL REMAIN
STALLED S OF THE REGION AND SUNDAY LOOKS PREDOMINANTLY DRY AS
WELL. SOME OF THE GUID IS INDICATING SOME POPS OVER THE EXTREME
SRN AREAS, WHILE OTHER GUID KEEPS THE POPS S OF THE CWA. SINCE THE
GFS (THE GUID WITH THE MOST NWD EXTENT) OFTEN OVERDOES ITS PRECIP
FIELD, AM INCLINED TO GO WITH THE OTHER SOLNS ATTM, BUT MAY NEED
TO INCREASE POPS LATER ON SUN ACRS THE S IF OTHER GUID COMES INTO
AGREEMENT.
BY MON, BOTH THE ECMWF AND GFS WANT TO BRING A WEAK LOW TO THE S
AND AGAIN ITS A QUESTION OF HOW FAR N ANY PRECIP WOULD COME. ONCE
AGAIN, THE GFS HAS A FURTHER N EXTENT, BUT BOTH MDLS INDICATE A
STRONGER LOW, SO HAVE BOUGHT OFF ON A MORE NRN EXTENT THIS TIME
AND BROUGHT SOME LOW POPS EVERYWHERE, BUT THIS IS LOW CONFIDENCE.
BY TUE, A CDFNT WILL BE APPROACHING FROM THE W AND WILL CROSS THE
REGION BY TUE NIGHT. THIS LOOKS TO BE OUR BEST CHC OF RAIN.
BEHIND THE CFP, HIGH PRESSURE WILL BUILD DOWN FROM THE NRN PLAINS
AND BRING DRY WX FOR WED AND THU.
TEMPS LOOK TO BE AT OR SLIGHTLY ABOVE NRML THRU MIDWEEK AND THEN
WILL BE A TAD BELOW NRML BEHIND THE TUE FROPA AS THE HIGH BUILDS
IN, DEW POINTS WILL BE QUITE PLEASANT FOR MID AUGUST THOUGH.
&&
.AVIATION /16Z FRIDAY THROUGH TUESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
PLENTY OF MVFR/IFR CONDITIONS ACROSS THE TERMINALS EARLY THIS
MORNING. THE SOUTHERLY FLOW OF HUMID AIR AND SEVERAL WEAK S/W MOVING
THROUGH THE FLOW WILL KEEP PLENTY OF SHOWERS ACROSS THE REGION TODAY
WITH THE AREAS NORTH/WEST BEING FAVORED EARLY AND THEN THE DEL
VALLEY AND SRN AREAS LATER THIS AFTERNOON. TSTMS ARE ALSO EXPECTED
MOSTLY THIS AFTERNOON AND EARLY EVENING. A COLD FRONT WILL CROSS THE
AREA LATER TODAY AND TONIGHT WITH IMPROVING CONDITIONS ARRIVING
BEHIND IT FRI NIGHT.
MOST MODELS ARE INDICATING ONE BATCH OF SHOWERS EARLY THIS MORNING
ACROSS THE NORTH...THEN MORE DURING THE MORNING NORTH/CENTRAL
FOLLOWED BY A BREAK THIS AFTERNOON...THEN MORE SCT TSTMS LATER THIS
AFTERNOON AND EVENING WITH THE FRONT. WE HAVE BLENDED THIS IN WITH
SOME INPUT FROM THE EARLIER TAFS TO ARRIVE AT A LOW-MOD CONFID FCST.
OUTLOOK...
SAT THROUGH MON...THERE COULD BE SOME LINGERING LOWER CIGS EARLY
SAT, ESPECIALLY ACRS THE S, OTHERWISE...MAINLY VFR CONDITIONS
EXPECTED. ISOLATED SHWRS/TSTMS REMAIN POSSIBLE, ESPECIALLY MONDAY.
HIGH CONFIDENCE.
TUES...VFR TO POSSIBLE MVFR AT TIMES WITH SCATTERED SHWRS/TSTMS
POSSIBLE AS CDFNT CROSSES THE REGION FROM W TO E. WNDSHFT WITH
CFP. MDT TO HIGH CONFIDENCE.
&&
.MARINE...
WINDS AND SEAS WILL SLOWLY BUILD TODAY AS THE LOW PRESSURE SYSTEM TO
THE NORTH AND ITS ATTACHED FRONT BEGIN TO MOVE TOWARD THE AREA. IT
APPEARS THAT THERE WILL BE A WEAK INVERSION IN PLACE TODAY...BUT
PROBABLY ENOUGH MIXING TO ALLOW SOME OF THE LOW LEVEL WINDS (AROUND
30 KTS) TO CREATE SOME GUSTS ACROSS THE NRN COASTAL WATERS. SEAS
ACROSS THESE AREAS MAY BUILD TO 5 FT...SO WE WILL RAISE THE SCA FLAG
FOR THE 12Z TO 00Z PERIOD TO COVER THESE ENHANCED CONDITIONS. SCT
SHOWERS/TSTMS EXPECTED ON ALL WATERS TODAY WITH LOCALLY HIGHER
WINDS/SEAS. TONIGHT...THE COLD FRONT WILL CROSS THROUGH WITH SCAT
SHOWERS/TSTMS EARLY THEN IMPROVING CONDITIONS. WINDS SHIFT TO WRLY
TONIGHT THEN NW BY MORNING.
OUTLOOK...
A COLD FRONT WILL BE TRACKING ACROSS THE CSTL WATERS, EVENTUALLY
STALLING TO OUR SOUTH THROUGH MON. SEAS ARE EXPECTED TO GENL BE IN
THE 2 TO 3 FT RANGE WITH SUSTAINED WINDS GENLY UNDER 10 KT AND
GUSTS UNDER 15 KT, SO SUB-ADVISORY CONDS ARE EXPECTED THRU THE PD.
&&
.HYDROLOGY...
FLASH FLOOD WATCH FOR NORTHERN COUNTIES. UP TO 4 INCHES OF RAIN HAS
FALLEN OVERNIGHT LEAVING THIS AREA MORE SUSCEPTIBLE TO FLOODING
TODAY. ELSEWHERE WHILE THERE IS A LOWER CHANCE, ITS NOT A ZERO
CHANCE, BUT THE MESOSCALE MODELS CONTINUE TO SHOW FAIRLY PROGRESSIVE
STORMS, SO UNLESS THERE IS TRAINING, THE RISK STILL APPEARS LOWER
THAN LOCATIONS THAT HAVE BEEN ALREADY DOUSED THE PAST 24 HOURS.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...FLASH FLOOD WATCH UNTIL 10 PM EDT THIS EVENING FOR PAZ054-055-
061-062.
NJ...FLASH FLOOD WATCH UNTIL 10 PM EDT THIS EVENING FOR NJZ001-
007>010.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR ANZ450-
451.
&&
$$
SYNOPSIS...NIERENBERG
NEAR TERM...GIGI
SHORT TERM...O`HARA
LONG TERM...NIERENBERG
AVIATION...NIERENBERG/O`HARA
MARINE...NIERENBERG/O`HARA
HYDROLOGY...
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
1012 AM EDT FRI AUG 9 2013
.SYNOPSIS...
HIGH PRESSURE CENTERED IN THE ATLANTIC WILL DIRECT A MOIST
ONSHORE FLOW INTO THE FORECAST AREA. A SLOW MOVING FRONTAL
SYSTEM WILL REMAIN NORTHWEST OF THE AREA THROUGH SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
THIS AFTERNOON...HIGH PRESSURE CENTERED OFFSHORE WILL CIRCULATE
MOIST AIR INTO THE FORECAST AREA. THIS MOISTURE PLUS HEATING
SHOULD HELP SUPPORT SHOWERS AND THUNDERSTORMS BUT EXPECT LIMITED
COVERAGE BECAUSE OF UPPER-LEVEL RIDGING AND SLOW MOVEMENT. LEANED
TOWARD THE MORE CONSISTENT GFS MOS POPS WHICH WERE MUCH LOWER THAN
THE NAM MOS POPS. THE HIGH-RESOLUTION MODELS DISPLAYED MAINLY
SCATTERED COVERAGE BUT THE 03Z HRRR DID APPEAR TO INDICATE
ENHANCED COVERAGE IN A BAND FROM AUGUSTA TO COLUMBIA THIS
AFTERNOON. THIS MAY BE ASSOCIATED WITH THE WEAK H7 SHORTWAVE
TROUGH CAUGHT IN THE RIDGE OVER THE FORECAST AREA SHOWN BY THE
LATEST RAP. VERY HEAVY RAIN WILL BE POSSIBLE WITH ANY
THUNDERSTORMS BECAUSE OF PRECIPITABLE WATER A LITTLE OVER 2 INCHES
AND SLOW STORM MOVEMENT. LEANED TOWARD THE WARMER GFS MOS
TEMPERATURES BASED ON YESTERDAY/S VERIFICATION.
TONIGHT...EVEN WITH HIGH MOISTURE LEVELS WITH PW VALUES NEAR 2 INCHES
EXPECT RAIN CHANCES TO DECREASE TO ABOUT 20 PERCENT WITH THE LOSS OF
DAYTIME HEATING. WARM AND MUGGY WITH LOWS IN THE LOWER TO MID 70S.
&&
.SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
THE MODELS CONTINUE TO SHOW A MOIST SOUTHERLY FLOW ASSOCIATED
WITH THE OFFSHORE HIGH WITH THE FRONTAL SYSTEM REMAINING NORTH OF
THE AREA. THE MOIST FLOW SUPPORTS SHOWERS AND THUNDERSTORMS BUT
STILL EXPECT LIMITED COVERAGE BECAUSE OF UPPER RIDGING AND SLOW
STORM MOVEMENT. MOST OF THE MOS GUIDANCE INDICATED JUST CHANCE
POPS. PRECIPITABLE WATER AROUND 2 INCHES PLUS SLOW STORM MOVEMENT
SUPPORTS POSSIBLE VERY HEAVY RAIN WITH ANY THUNDERSTORMS. USED THE
GUIDANCE CONSENSUS FOR THE TEMPERATURE FORECAST.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
THE GFS AND ECMWF DISPLAY A FRONT NEAR THE FORECAST AREA THROUGH THE
MEDIUM-RANGE PERIOD. THE MODELS SHOW FLAT UPPER RIDGING EARLY
WITH TROUGHING BEGINNING TUESDAY. THIS PATTERN SUPPORTS POPS ABOVE
CLIMATOLOGY. HIGH PRECIPITABLE WATER AND POSSIBLE TRAINING ALONG
THE EAST-WEST ORIENTED FRONT MAY LEAD VERY HEAVY RAINFALL DURING
PART OF THE PERIOD.
&&
.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
MVFR/IFR STRATUS MOVING INTO THE AREA THIS MORNING WHICH WILL
PERSIST UNTIL AROUND 15Z DUE TO A MOIST SOUTHEAST LOW LEVEL FLOW.
VFR CONDITIONS EXPECTED TO RETURN AFTER 14Z AS BOUNDARY LAYER
MIXING TAKES HOLD. SCATTERED CONVECTION POSSIBLE THIS AFTERNOON
INTO EARLY THIS EVENING BUT COVERAGE TOO LIMITED TO INCLUDE IN
TAFS AT THIS TIME.
EXTENDED AVIATION OUTLOOK...RESTRICTIONS POSSIBLE IN AFTERNOON
CONVECTION AS WELL AS LATE NIGHT/EARLY MORNING FOG/STRATUS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
647 AM EDT FRI AUG 9 2013
.SYNOPSIS...
HIGH PRESSURE CENTERED IN THE ATLANTIC WILL DIRECT A MOIST
ONSHORE FLOW INTO THE FORECAST AREA. A SLOW MOVING FRONTAL
SYSTEM WILL REMAIN NORTHWEST OF THE AREA THROUGH SATURDAY.
&&
.NEAR TERM /THROUGH TODAY/...
HIGH PRESSURE CENTERED OFFSHORE WILL CIRCULATE MOIST AIR INTO THE
FORECAST AREA. THIS MOISTURE PLUS HEATING SHOULD HELP SUPPORT
SHOWERS AND THUNDERSTORMS BUT EXPECT LIMITED COVERAGE BECAUSE OF
UPPER-LEVEL RIDGING AND SLOW MOVEMENT. LEANED TOWARD THE MORE
CONSISTENT GFS MOS POPS WHICH WERE MUCH LOWER THAN THE NAM MOS
POPS. THE HIGH-RESOLUTION MODELS DISPLAYED MAINLY SCATTERED
COVERAGE BUT THE 03Z HRRR DID APPEAR TO INDICATE ENHANCED
COVERAGE IN A BAND FROM AUGUSTA TO COLUMBIA THIS AFTERNOON. THIS MAY
BE ASSOCIATED WITH THE WEAK H7 SHORTWAVE TROUGH CAUGHT IN THE
RIDGE OVER THE FORECAST AREA SHOWN BY THE LATEST RAP. VERY HEAVY
RAIN WILL BE POSSIBLE WITH ANY THUNDERSTORMS BECAUSE OF
PRECIPITABLE WATER A LITTLE OVER 2 INCHES AND SLOW STORM MOVEMENT.
LEANED TOWARD THE WARMER GFS MOS TEMPERATURES BASED ON YESTERDAY/S
VERIFICATION.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
THE MODELS CONTINUE TO SHOW A MOIST SOUTHERLY FLOW ASSOCIATED
WITH THE OFFSHORE HIGH WITH THE FRONTAL SYSTEM REMAINING NORTH OF
THE AREA. THE MOIST FLOW SUPPORTS SHOWERS AND THUNDERSTORMS BUT
STILL EXPECT LIMITED COVERAGE BECAUSE OF UPPER RIDGING AND SLOW
STORM MOVEMENT. MOST OF THE MOS GUIDANCE INDICATED JUST CHANCE
POPS. PRECIPITABLE WATER AROUND 2 INCHES PLUS SLOW STORM MOVEMENT
SUPPORTS POSSIBLE VERY HEAVY RAIN WITH ANY THUNDERSTORMS. USED THE
GUIDANCE CONSENSUS FOR THE TEMPERATURE FORECAST.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
THE GFS AND ECMWF DISPLAY A FRONT NEAR THE FORECAST AREA THROUGH THE
MEDIUM-RANGE PERIOD. THE MODELS SHOW FLAT UPPER RIDGING EARLY
WITH TROUGHING BEGINNING TUESDAY. THIS PATTERN SUPPORTS POPS ABOVE
CLIMATOLOGY. HIGH PRECIPITABLE WATER AND POSSIBLE TRAINING ALONG
THE EAST-WEST ORIENTED FRONT MAY LEAD VERY HEAVY RAINFALL DURING
PART OF THE PERIOD.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
MVFR/IFR STRATUS MOVING INTO THE AREA EARLY THIS MORNING WHICH WILL
PERSIST UNTIL AROUND 14Z DUE TO A MOIST SOUTHEAST LOW LEVEL FLOW.
VFR CONDITIONS EXPECTED TO RETURN AFTER 14Z AS BOUNDARY LAYER MIXING
TAKES HOLD. SCATTERED CONVECTION POSSIBLE THIS AFTERNOON INTO EARLY
THIS EVENING BUT COVERAGE TOO LIMITED TO INCLUDE IN TAFS AT THIS
TIME.
EXTENDED AVIATION OUTLOOK...RESTRICTIONS POSSIBLE IN AFTERNOON
CONVECTION AS WELL AS LATE NIGHT/EARLY MORNING FOG/STRATUS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
657 AM CDT FRI AUG 9 2013
.UPDATE...
ISSUED AT 642 AM CDT FRI AUG 9 2013
SHALLOW PATCHY GROUND FOG HAS DEVELOPED ALONG/EAST OF THE
MISSISSIPPI IN WEST CENTRAL ILLINOIS. THE FEW OBS REPORTING THIS
FOG DO SHOW IT IS LOCALLY DENSE AT TIMES. WITH THE SUN ALREADY
UP...CONDITIONS SHOULD BEGIN TO IMPROVE OVER THE NEXT 90 MINUTES
SO NO HEADLINE IS BEING CONSIDERED.
THE SPRINKLES AND ISOLATED SHOWERS OVER CENTRAL/SOUTHERN IOWA HAVE
DISSIPATED AS THE FORCING WEAKENED. ALONG THE MN/IA BORDER THIS
CONVECTION IS ALSO WEAKENING AS LIFT AND CONVERGENCE WEAKENS. THE
FRONTAL PASSAGE ACROSS THE AREA IS EXPECTED TO BE MAINLY DRY DUE
TO WEAK FORCING AND NOT MUCH IN THE WAY OF MOISTURE.
HOWEVER...ISOLATED WEAK DIURNAL SPRINKLES/SHOWERS CANNOT BE
ENTIRELY RULED OUT DUE TO THE TIMING OF THE FRONTAL PASSAGE. IF
DIURNAL CONVECTION DEVELOPS IT WILL DISSIPATE SHORTLY AFTER SUNSET.
&&
.SYNOPSIS...
ISSUED AT 303 AM CDT FRI AUG 9 2013
06Z SFC ANALYSIS HAS WEAK LOWS ASSOCIATED WITH A FRONTAL BOUNDARY IN
THE OHIO VALLEY WITH A THUNDERSTORM COMPLEX ACROSS OKLAHOMA. A WEAK
FRONT/BOUNDARY RAN FROM EASTERN LAKE SUPERIOR...TO KYKN...AND THEN
ACROSS SOUTHERN SOUTH DAKOTA. RADAR HAS WEAK RETURNS ACROSS CENTRAL
IOWA MAINLY IN THE FORM OF SPRINKLES AND SLIGHTLY STRONGER RETURNS
ACROSS NORTHERN IOWA NEAR THE BOUNDARY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 303 AM CDT FRI AUG 9 2013
THE WEAK RETURNS ACROSS CENTRAL AND SOUTHERN IOWA IS OCCURRING FROM
A MID LEVEL CLOUD DECK AND IS LIKELY SPRINKLES. THE BETTER RADAR
RETURNS ALONG THE MN/IA BORDER IS IN AN AREA OF BETTER LIFT.
HOWEVER...THIS LIFT IS PROGGED TO WEAKEN THROUGH SUNRISE PER TRENDS
FROM THE RAP AND OTHER MODELS. RECENT RADAR TRENDS SEEM TO SUPPORT
THIS SCENARIO WITH NOT ONLY THE NORTHERN RADAR RETURNS BUT THE
SOUTHERN RADAR RETURNS.
THUS MAYBE SOME SPRINKLES MAY ENTER THE FAR WESTERN/NORTHWEST PARTS
OF THE CWFA PRIOR TO SUNRISE BEFORE DISSIPATING.
THE WEAK FRONT/BOUNDARY SLOWLY MOVES THROUGH THE CWFA DURING THE
DAY. LIFT IS VERY WEAK AND THE BETTER MOISTURE IS SOUTH OF THE AREA.
THUS ISOLATED SPRINKLES ARE THE MORE PROBABLE PRECIPITATION TYPE
DURING THE DAY. POSSIBLY A COUPLE OF ISOLATED DIURNAL SHOWERS MAY
DEVELOP DURING THE AFTERNOON WHEN HEATING IS THE STRONGEST.
TONIGHT...ANY SPRINKLES/DIURNAL SHOWERS THAT DEVELOP WILL DISSIPATE
WITH SUNSET LEAVING THE REMAINDER OF THE NIGHT DRY AS HIGH PRESSURE
BUILDS INTO THE MIDWEST. THE MCS TOOL POINTS TO THE BETTER SUPPORT
BEING SOUTH OF THE CWFA WHICH IS WHERE THE BETTER MOISTURE IS
LOCATED.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 303 AM CDT FRI AUG 9 2013
MAINLY DRY WITH NEAR TO SLIGHTLY BELOW NORMAL TEMPS AS NORTHWEST
FLOW ALOFT REMAINS IN PLACE OVER THE REGION.
SAT-SAT NGT... MORE FANTASTIC WEATHER FOR OUTDOOR ACTIVITIES WITH
SURFACE TO 850 MB HIGH PRESSURE RIDGE PROVIDING LIGHT NORTHERLY
WINDS USHERING IN DRIER AIR AND COMFORTABLE HUMIDITY WITH HIGHS
MAINLY IN RANGE OF 77-83F. LOWS SAT NGT MAINLY IN RANGE OF 57-63F
WITH SOME INTERVALS OF MID/HIGH CLOUDS FROM UPSTREAM CONVECTION
PARTS OF SD/MN/NW-N IA ATTENDANT TO SHORTWAVE AND ELEVATED WARM
MOIST ADVECTION NORTH OF SURFACE BOUNDARY.
SUN-MON... WEAK SHORTWAVE AND FRONTAL BOUNDARY TO RESULT IN CHC
OF PCPN. LACK OF DEEP MOISTURE AND WEAK FORCING SUGGESTED ATTIM
SUPPORTIVE OF MOSTLY LIGHT QPF AMOUNTS. PCPN CHC MAY HOLD OFF
UNTIL MON ACROSS THE SOUTHERN CWA WITH CONTINUED INFLUX OF
DRIER AIR FROM DEPARTING HIGH. BUT THEN ON MON... MAY SEE PCPN
SHIFT FROM THE NORTH AND FOCUS MORE ACROSS SOUTHERN CWA DEPENDING
ON TIMING OF BOUNDARY. EXPECT TEMPS TO RECOVER ON SUN TO AROUND
NORMAL WITH DEVELOPING SOUTH WINDS AND DEEPER MIXING TO JUST ABOVE
850 MB SUPPORTIVE OF HIGHS IN THE LOW TO MID 80S. HOWEVER... DEBRIS
CLOUDS IN FAR NORTH SUN COULD LIMIT HIGHS THERE IN THE 70S ALONG/N
OF HWY 20. SUN NGT WITH CLOUDS AND PRE-FRONTAL SOUTH WINDS SHOULD
YIELD MILDER LOWS IN THE 60S. MON WILL BE FEW TO SEVERAL DEGS
COOLER ON HIGHS WITH MAINLY UPPER 70S TO LOWER 80S DUE TO CLOUDS
AND FRONTAL PASSAGE.
TUE-THU... HIGH PRESSURE TO BECOME RE-ESTABLISHED ACROSS THE REGION
AND LIKELY REMAIN DOMINANT FEATURE THROUGH THE PERIOD KEEPING
TEMPS BELOW NORMAL AND DRY CONDITIONS WITH VERY COMFORTABLE HUMIDITY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 642 AM CDT FRI AUG 9 2013
SHALLOW PATCHY GROUND FOG HAS CREATED VLIFR CONDITIONS AT KBRL.
THESE CONDITIONS WILL IMPROVE TO VFR THROUGH 14Z/09. OTHERWISE
EXPECT VFR CONDITIONS THROUGH 12Z/10 AS A WEAK FRONT MOVES THROUGH
THE AREA. ISOLATED SPRINKLES MAY BE POSSIBLE THROUGH 21Z/09 BUT
THE PROBABILITY OF A SHRA AFFECTING A TAF SITE IS AT BEST 5
PERCENT. ..08..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...08
SYNOPSIS...08
SHORT TERM...08
LONG TERM...05
AVIATION...08
AREA FORECAST DISCUSSION
NWS DES MOINES IA
641 AM CDT FRI AUG 9 2013
.SHORT TERM.../TODAY /...
ISSUED AT 313 AM CDT FRI AUG 9 2013
WEAK COLD FRONTAL BOUNDARY EXTENDING FROM FROM MN INTO NWRN IA INTO
KS WILL MOVE SOUTHEAST AND EXIT THE CWA BY AROUND MID DAY. SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS OCCURRING ALONG THE FRONT WILL
CONTINUE TO MOVE ESEWD WITH THE FRONT HRRR HAS A PRETTY DECENT
HANDLE ON THE PRECIP AND SUGGESTS THE PRECIP WILL BE OUT OF THE CWA
BY AROUND 18Z. HIGH PRESSURE WILL BEGIN BUILDING INTO THE STATE
THIS AFTERNOON FROM THE NORTHWEST.
.LONG TERM.../TONIGHT THROUGH THURSDAY/...
ISSUED AT 313 AM CDT FRI AUG 9 2013
SIMILAR CHALLENGES COMING UP COMPARED TO PAST FEW DAYS. APPROACHING
SHORT WAVES AND SYNOPTIC FEATURES REMAIN RATHER WEAK GIVEN TIME OF
YEAR AND QUESTIONS REVOLVING AROUND COVERAGE AND CHANCES FOR RAIN IN
THE FORECAST. FOR NOW...WEAK BOUNDARY WILL BE SOUTH OF THE REGION BY
THIS EVENING AND DRY WEATHER EXPECTED THROUGH LATE SATURDAY NIGHT.
FINALLY ON SUNDAY ANOTHER NORTHERN STREAM WAVE WILL ATTEMPT TO CROSS
THE AREA WITH SOME MOISTURE ASSOCIATED WITH IT. THIS WILL ONCE AGAIN
BRING CHANCES FOR SHOWERS AND THUNDERSTORMS TO THE AREA SUNDAY INTO
MONDAY AFTERNOON. FOLLOWING THAT HIGH PRESSURE WILL DROP SOUTH OUT
OF CANADA AND KEEP TEMPERATURES COMFORTABLE IN THE UPPER 70S TO
LOWER 80S WITH SLIGHTLY COOLER READINGS OVER THE NORTH. OVERALL
QUITE PLEASANT FOR AUGUST...THOUGH A BIT BELOW NORMAL. MOST OF THE
MED RANGE MODELS SUGGEST THAT THE HIGH OVER THE GREAT LAKES WILL
REMAIN ANCHORED THERE UNTIL MID TO LATE NEXT WEEK. FOR THE MOST PART
OUR WEATHER WILL REMAIN RATHER UNEVENTFUL WITH DRIER AND COOLER THAN
NORMAL CONDITIONS.
&&
.AVIATION...09/12Z
ISSUED AT 637 AM CDT FRI AUG 9 2013
WEAK COLD FRONT NERN IA INTO SOUTH CENTRAL IOWA WILL PASS
SOUTHEAST OF THE STATE THIS MORNING. ISOLATED SHOWERS OVER THE
NE RN PART OF THE STATE WILL END THIS MORNING. MID LEVEL CLOUDINESS
WILL CLEAR OUT OF THE STATE BY MID MORNING...WITH ONLY HIGH CLOUDS
REMAINING OVER THE SERN HALF. FLOW BECOMING NW-NLY STATEWIDE TODAY.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...MS AUG 13
LONG TERM...REV
AVIATION...MS AUG 13
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
745 AM EDT FRI AUG 9 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 458 AM EDT FRI AUG 9 2013
WV IMAGERY AND RUC ANALYSIS INDICATED SEVERAL WEAK SHORTWAVES
ROTATING AROUND A MID/UPPER LEVEL LOW OVER NRN ONTARIO. SCT/ISOLD
-SHRA PERSISTED MAINLY ACROSS THE SRN CWA SUPPORTED BY A WEAK
850-700 MB TROUGH AND UPPER LEVEL DIV WITH THE RIGHT ENTRANCE OF A
115 KNOT 300 MB JET TO THE NE OF LAKE SUPERIOR. A SHORTWAVE TROUGH
NW OF LAKE SUPERIOR ALSO SUPPORTED SOME ISOLD/SCT SHOWERS OVER NW
ONTARIO FROM SIOUX LOOKOUT TO DRYDEN.
TODAY...RADAR/SATELLITE TRENDS AND SHORT RANGE MODELS SUGGEST THAT
THE SHOWERS EARLY THIS MORNING WILL DEPART TO THE EAST OF THE CWA BY
AROUND 12Z. ALTHOUGH THE STRONGER 700-500 MB QVECTOR CONV ASSOCIATED
WITH THE NW ONTARIO SHRTWV WILL REMAIN NORTH OF UPPER MICHIGAN...THE
TAIL OF THIS FEATURE COMBINED WITH LOW LEVEL CONV ALONG THE LAKE
SUPERIOR BREEZE BOUNDARY AND MINIMAL MLCAPE VALUES TO NEAR 200 J/KG
IS EXPECTED TO GENERATE ISOLD -SHRA OVER INLAND PORTIONS OF
EAST CNTRL UPPER MICHIGAN. SOME -SHRA MAY ALSO BE POSSIBLE FARTHER
WEST FROM ESC-IMT ALONG A WEAK SFC TROUGH BUT CONFIDENCE WAS LOWER
SO PCPN WAS NOT MENTIONED AT THIS TIME. OTHERWISE...850 MB TEMPS
FROM 7C-9C WILL SUPPORT SCT/BKN CU DEVELOPMENT WITH CONTINUED BELOW
NORMAL HIGHS IN THE UPPER 60S AND LOWER 70S ARE EXPECTED.
TONIGHT...WITH THE LOSS OF DAYTIME HEATING AND HIGH PRES BUILDING
INTO THE REGION...CLEARING SKIES AND DIMINISHING WINDS WILL LEAD TO
FAVORABLE RADIATIONAL COOLING CONDITIONS OVERNIGHT. SO...KEPT FCST
MINS CLOSER TO THE LOWER END OF GUIDANCE...WITH READINGS INTO THE
LOWER TO MID 40S INLAND AND IN THE LOWER 50S ALONG THE GREAT LAKES.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 458 AM EDT FRI AUG 9 2013
OTHER THAN A PERIOD OF SCATTERED SHOWERS AND A FEW THUNDERSTORMS
SUNDAY AFTERNOON INTO MONDAY MORNING...A RATHER EXTENDED PERIOD OF
DRY WEATHER IS EXPECTED WITH SLIGHTLY BELOW NORMAL TEMPERATURES
THROUGH MUCH OF NEXT WEEK.
SATURDAY...DRY AIR WILL CONTINUE TO FILTER IN EARLY IN THE MORNING
AS A REINFORCING SFC HIGH AND WEAK RIDGING MOVE IN FROM THE WEST.
THERE HAS BEEN SOME HINT AT ISOLATED DIURNAL SHOWERS FORMING ACROSS
INTERIOR LOCATIONS BY BOTH THE NAM AND THE GFS OFF AND ON OVER THE
PAST TWO DAYS. INVESTIGATION OF FORECAST SOUNDINGS ACROSS THE CWA
SHOW WIDESPREAD CUMULUS DEVELOPMENT WITH 5 TO 7 KFT DEPTH. GIVEN
SHALLOW CLOUD DEPTH AND INSUFFICIENT MOISTURE ELSEWHERE IN THE
LAYER...ENTRAINMENT OF DRY AIR INTO THE CUMULUS FIELD SHOULD PREVENT
PRECIP DEVELOPMENT. IF ANY SHOWERS WERE TO FORM...THEY WOULD BE VERY
LIGHT AND LIKELY FOCUSED ON LAKE BREEZE CONVERGENCE ZONES ACROSS THE
INTERIOR CENTRAL AND EAST.
SATURDAY NIGHT THROUGH MONDAY NIGHT...WEAK SHORTWAVE RIDGING WILL BE
EXITING TO THE EAST SATURDAY EVENING AS A LARGE TROUGH AXIS ROTATES
SOUTHWARD ON THE BACKSIDE OF A DEEP EASTERN CANADIAN TROUGH. MODELS
HAVE BEEN PICKING UP ON A WEAK LEAD SHORTWAVE TROUGH TRACKING ACROSS
LAKE SUPERIOR SATURDAY NIGHT. DO NOT EXPECT MUCH MORE THAN SOME
INCREASED CLOUDINESS WITH THE WAVE. THE MAIN TROUGH AXIS THEN BEGINS
TO PUSH INTO THE AREA BY SUNDAY MORNING. THE 00Z NAM IS QUITE
AGGRESSIVE WITH BRINGING PRECIP INTO THE WESTERN CWA LATE SATURDAY
NIGHT AS IT APPEARS TO HAVE FALLEN VICTIM TO CONSIDERABLE
CONVECTIVE FEEDBACK FROM A POSSIBLE MCS ACROSS SOUTHERN MN. WILL
THEREFORE IGNORE THIS SOLUTION AND KEEP CONDITIONS DRY SATURDAY
NIGHT.
WITH MANY OF THE MODELS INDICATING DECENT MOISTURE TRANSPORT AND
ISENTROPIC LIFT CONFINED TO SOUTHERN MN AND CENTRAL/SOUTHERN WI...DO
NOT SEE THAT GREAT OF A POTENTIAL FOR ACTIVITY ACROSS THE CWA ON
SUNDAY. THE MAIN WILD CARD FOR THE DAY WILL BE HOW CLOUD DEBRIS FROM
ACTIVITY TO THE SOUTH LIMITS DAYTIME HEATING. WITH OVERALL MOISTURE
PROFILES ABOVE H7 QUITE DRY ACROSS UPPER MI...CLOUD COVER SHOULD
EASILY ERODE AND NOT INHIBIT OPTIMAL HEATING.
FOUND THE 00Z GFS QUITE REASONABLE WITH THE OVERALL SYNOPTIC
SET-UP...SO GAVE IT MORE WEIGHT IN THE FORECAST. A WEAK SECONDARY
SHORTWAVE WILL BE A FOCUS FOR AFTERNOON SHOWER AND STORM DEVELOPMENT
AS THE WAVE REACHES THE CENTRAL CWA BY MID AFTERNOON. WITH NORTHWEST
FLOW ALOFT...0 TO 6 KM BULK SHEAR WILL BE ON THE ORDER OF 35 KNOTS.
HOWEVER...SFC DEW POINTS ONLY IN THE MID 50S WILL LEAD TO POOR
INSTABILITY IN THE FORM OF MLCAPE OF 600 TO 900 J/KG. THIS SHOULD
LIMIT ANY ORGANIZED CONVECTION...AND OVERALL THUNDER COVERAGE FOR
THAT MATTER. HOWEVER...WITH A DRY SUBCLOUD LAYER AND DOWNDRAFT CAPE
OVER 1000 J/KG...THERE IS AN ELEVATED POTENTIAL FOR GUSTY WINDS
UNDER ANY STRONGER SHOWERS/STORMS. BEST CHANCE OF ANY CONVECTION
WILL BE SOUTH CENTRAL AND INTERIOR EAST IN THE AFTERNOON.
EXPECT ANY ACTIVITY TO DIMINISH WITH THE LOSS OF DAYTIME HEATING
SUNDAY EVENING. FORCING IS QUITE CONVOLUTED AT THIS POINT...WITH THE
POTENTIAL FOR MULTIPLE WEAK SHORTWAVES TO TRACK ACROSS THE CWA
THROUGH MONDAY. HAVE OPTED TO KEEP A GENERAL SLIGHT CHANCE OF
SHOWERS IN THE FORECAST FOR SUNDAY NIGHT AND MONDAY GIVEN
UNCERTAINTY OF LOCATIONS FOR BEST FORCING. OVERALL THINKING IS THAT
THE PERIOD WILL BE MOSTLY DRY WITH ONLY SEE ISOLATED SHOWERS FROM
TIME TO TIME.
MONDAY NIGHT THROUGH THURSDAY...MODEL AGREEMENT IS GOOD WITH
BRINGING IN MID-LEVEL RIDGING FROM THE WEST BY MID-WEEK. THERE
IS...HOWEVER...SOME DISAGREEMENT AT HOW QUICK THE TROUGH AXIS
COMPLETELY CLEARS THE CWA. THE GFS HAS SPED UP THE TROUGH OVER
RECENT RUNS...THE ECMWF HAS SLOWED THE TROUGH...AND THE GEM HAS HAS
WEAKENED THE TROUGH. NOT MUCH ONE CAN DO WITH THIS INFORMATION OTHER
THAN STICK WITH CONSENSUS DATA. WITH LIMITED MID-LEVEL
MOISTURE...WILL KEEP PRECIP OUT OF THE FORECAST FOR MONDAY NIGHT AND
TUESDAY. HIGH PRESSURE WILL THEN DOMINATE THE WEATHER THROUGH
THURSDAY. ANOTHER GOOD STRING OF NIGHTS WITH GOOD RADIATIONAL
COOLING APPEAR LIKELY...WITH TUESDAY NIGHT LEADING THE WAY AS THE
SFC HIGH SETTLES OVER THE WESTERN CWA. HAVE THUS LOWERED MIN TEMPS
SEVERAL DEGREES. THE GFS HINTS AT ISOLATED SHOWERS INTERIOR WEST ON
WEDNESDAY AFTERNOON...BUT A STOUT INVERSION WITH LIMITED RETURN
MOISTURE SHOULD PREVENT DEVELOPMENT.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 745 AM EDT FRI AUG 9 2013
CONDITIONS ARE EXPECTED TO REMAIN VFR THROUGH THE TAF PERIOD.
ANOTHER TROUGH IS EXPECTED TO MOVE THROUGH UPPER MICHIGAN TODAY THAT
COULD SET OFF SOME PCPN...MAINLY FOR SAW. HOWEVER...WITH DRY AIR
OVER THE REGION...SHRA CHANCES/COVERAGE/INTENSITY WILL BE LOW AND WAS NOT
INCLUDED IN THE TAF. OTHERWISE...WEST WINDS WILL INCREASE AND BECOME
GUSTY BY MIDDAY...ESPECIALLY OVER THE EXPOSED HIGHER TERRAIN AT CMX.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 458 AM EDT FRI AUG 9 2013
WRLY WINDS ARE EXPECTED TO INCREASE INTO THE 15 TO 25 RANGE TODAY
BEHIND A TROUGH MOVING THROUGH LAKE SUPERIOR. HOWEVER...THE STRONGER
WINDS WILL BE RELATIVELY BRIEF SO MAX WAVE HEIGHTS ARE EXPECTED TO
REMAIN MAINLY IN THE 3 TO 5 FOOT RANGE. WINDS WILL VEER NW LATE
TODAY AND DIMINISH TONIGHT TO 5 TO 15 KNOTS AS HIGH PRES BUILDS INTO
THE REGION.
THE COMBINATION OF HIGH PRESSURE TRACKING SOUTHEASTWARD THROUGH WI
AND LOW PRESSURE DROPPING SOUTHWARD FROM NORTHWEST ONTARIO SATURDAY
WILL BRING W TO NW WINDS OF 10 TO 20 KNOTS ACROSS MUCH OF THE LAKE.
THE TROUGH WILL SLOWLY CROSS THE LAKE SUNDAY AFTERNOON THROUGH
MONDAY WITH WINDS UNDER 15 KNOTS. HIGH PRESSURE WILL THEN DOMINATE
THE REGION THROUGH THE MIDDLE OF NEXT WEEK AND PRODUCE WINDS UNDER
15 KNOTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KLUBER
AVIATION...JLB
MARINE...JLB/KLUBER
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON MS
955 AM CDT FRI AUG 9 2013
.UPDATE...LATEST SATELLITE IMAGERY SHOWED THAT THE MEAN UPPER RIDGE
WAS STARTING TO SHOW SIGNS OF SOME SLIGHT WEAKENING. THIS WAS NOTED
BY THE 850-700 MB INVERTED TROUGH OVER THE SOUTH HALF. AREA RADARS
WERE STARTING TO PICK UP SOME CONVECTION ACROSS THE COAST. WITH
CURRENT RADAR TRENDS HAVE PUSHED BACK GENERAL RAIN COVERAGE TIME IN
THE GRIDS. PWATS DOWN AT KLIX WAS AROUND 2.3 INCHES...WHILE 2
INCHES AT KJAN. PWATS WERE INCREASING FROM THE SOUTH AS DEEPER
TROPICAL MOISTURE WAS ADVANCING NORTH ACROSS THE REGION. EVEN THOUGH
JAN SOUNDING SHOWS SOME GOOD DCAPE THE ADVANCING DEEPER TROPICAL
MOISTURE WILL REDUCE DCAPES SOME FOR THIS AFTERNOON. HOWEVER A
FEW STRONG STORMS WITH SOME GUSTY WINDS AND LOCALLY HEAVY DOWNPOURS
IS NOT OUT OF THE QUESTION. LATEST HRRR SHOWS SOME DECENT COVERAGE AS
MOISTURE CONVERGENCE AND MOISTURE TRANSPORT OF TROPICAL MOISTURE
INCREASES SOME TODAY AROUND THE INVERTED TROUGH. SO WILL KEEP
CURRENT SCATTERED POPS FOR THIS AFTERNOON. CURRENT HOURLY TEMPS
LOOKED TO BE ON TRACK FOR THIS MORNING. AS FAR AS HEAT ADVISORY IS
CONCERN SOME AREAS MAY STRUGGLE TO REACH CRITERIA IN THE EASTERN
PORTION...BUT WILL CONTINUE TO KEEP THE ADVISORY IN PLACE FOR THE
WEST HALF. WILL KEEP THE CURRENT HIGHS FROM THE LOWER 90S EAST TO
THE UPPER 90S IN SOUTHEAST ARKANSAS./17/
./PREVIOUS DISCUSSION...426 AM CDT FRI AUG 9 2013
.DISCUSSION...
TODAY THROUGH SATURDAY NIGHT...
A FEW STORMS THAT DEVELOPED A FEW HOURS AGO OVER NORTH CENTRAL MS
ALONG AN OUTFLOW BOUNDARY HAVE DISSIPATED. OVERALL...THE PATTERN
REMAINS THE SAME WITH A VERY HOT AND HUMID AIRMASS ANCHORED OVER THE
ARKLAMISS REGION. THE HEAT ADVISORY WILL CONTINUE FOR ABOUT THE
WESTERN HALF OF THE FORECAST AREA...BUT CONVECTIVE COVERAGE MAY
EXTEND A LITTLE FARTHER WEST THAN IN RECENT DAYS.
THE HEAT ADVISORY IS A LITTLE MORE PROBLEMATIC TODAY AS EXPLICIT
FORECASTED HEAT INDICES ARE A BIT LOWER THAN HEAT ADVISORY THRESHOLD.
WITH TEMPERATURES STRUGGLING TO FALL BELOW 80 DEG F THIS MORNING
AFTER SEVERAL DAYS OF HIGH HEAT STRESS...WOULD RATHER NOT CANCEL THE
ADVISORY JUST YET. AS HAS BEEN THE CASE...LOCATIONS IN EASTERN MS
SHOULD EXPERIENCE A SHORTER DURATION OF 105+ HEAT INDICES BEFORE
AFTERNOON CONVECTION BRINGS SOME RELIEF. GUIDANCE IS ACTUALLY A
LITTLE HOTTER FOR SATURDAY THAN TODAY IN MANY LOCATIONS. HAVE
EXTENDED THE HEAT ADVISORY FOR PORTIONS OF THE DELTA REGION WHERE
CONFIDENCE IS GREATEST...BUT THE ADVISORY MAY NEED TO BE EXPANDED IF
THE FORECAST FOR GREATER HEAT CONTINUES.
AS FOR THUNDERSTORM POTENTIAL...MODELS INDICATE THAT THE HIGHLY
DIURNAL ISOLATED-SCATTERED THUNDERSTORM PATTERN WILL CONTINUE FOR
TODAY AND SATURDAY WITH THE BEST THERMODYNAMIC ENVIRONMENT AND DEEP
LAYER MOISTURE AND CONVERGENCE SHIFTING FARTHER NORTHWEST WITH TIME
AS MOISTURE TRANSPORT FROM THE GULF INCREASES. MID LEVEL LAPSE RATES
HAVE STEEPENED A BIT...AND COMBINED WITH THE VERY HOT SURFACE
TEMPERATURES/STEEP LOW LEVEL LAPSE RATES...THEY COULD INCREASE THE
RISK FOR STRONG MICROBURSTS DURING PEAK HEATING. IN ADDITION...SUBTLE
WEAKENING/SUPPRESSION OF THE RIDGE WILL ALLOW PERTURBATIONS IN THE
WESTERLIES TO INFRINGE UPON NORTHERN PORTIONS OF THE ARKLAMISS AND
HAVE INCREASED POPS THERE JUST A LITTLE. /EC/
SUNDAY THROUGH FRIDAY...
THE PATTERN FOR THE FIRST PART OF NEXT WEEK FEATURES AN EAST-WEST
DRAPED SURFACE FRONT JUST TO OUR NORTH...WITH A "FLAT" SUBTROPICAL
RIDGE AXIS OVER THE ARKLAMISS THAT EXTENDS OVER THE SOUTHERN PLAINS.
SURFACE HIGH PRESSURE WILL BE CENTERED OFF TO OUR EAST KEEPING
WARM/HUMID SOUTHERLY FLOW OFF THE GULF IN PLACE...AND IT LOOKS LIKE
AN ENHANCED SEA BREEZE COULD BRING SOME DECENT RAIN CHANCES TO
SOUTHERN ZONES SUNDAY AFTERNOON WITH JUST ISOLATED TO SCATTERED
DIURNAL CONVECTION FURTHER NORTH. FROM THERE IT APPEARS RAIN CHANCES
WILL BE ON THE INCREASE HEADED INTO THE FIRST PART OF THE WORK WEEK
AS THE UPPER RIDGE SHIFTS WEST AND HEIGHTS FALL ACROSS THE DEEP
SOUTH. WHILE MOST OF THIS ACTIVITY SHOULD BE CONFINED TO THE
AFTERNOON AND EARLY EVENING HOURS THE POSSIBILITY FOR SOME ACTIVITY
PERSISTING OVERNIGHT WILL BE A BIT HIGHER GIVEN PASSING UPPER
DISTURBANCES IN THIS PATTERN. THE INCREASED RAIN CHANCES AND FALLING
HEIGHTS WILL ALSO ALLOW TEMPERATURES TO RETURN CLOSER TO NORMAL FOR
MID AUGUST/GENERALLY LOWER 90S. CONVECTIVE PARAMETERS LOOK TO
SUPPORT A FEW STRONG STORMS DURING THIS PERIOD...BUT NOTHING OUT OF
ORDINARY FOR THIS TIME OF YEAR AND WILL OMIT MENTION OF ANY
SPECIFICS IN THE HWO.
THE MODELS CONTINUE TO SHOW THE AFOREMENTIONED SURFACE FRONT DROPPING
SOUTH INTO THE ARKLAMISS BY WEDNESDAY...PROVIDING FOCUS FOR AREAWIDE
SHOWERS AND THUNDERSTORMS AS THIS OCCURS. ALTHOUGH SPECIFICS ARE
STILL UP IN THE AIR IT DOES LOOK LIKE THE FRONT WILL DRIFT ALL THE
WAY ACROSS THE ARKLAMISS BY LATE THU OR SOMETIME FRI ALLOWING DRIER
AIR TO FILTER IN...A WELCOME CHANGE CONSIDERING THE STRETCH OF HOT AND
HUMID WEATHER WE`VE BEEN THROUGH RECENTLY. OVERNIGHT LOWS FALLING
INTO THE MID TO UPPER 60S WILL BE MUCH ANTICIPATED LATE IN THE WEEK
AND HOPEFULLY OVER THE WEEKEND AS A RESULT.
OTHER THAN A FEW MINOR ADJUSTMENTS THE GFS MOS POPS/TEMPS LOOKED
REASONABLE THROUGH THE EXTENDED RANGE. /BK/
&&
.AVIATION...THE BRIEF PERIOD OF MVFR CATEGORY FOG AND PATCHY AREAS
OF IFR/MVFR CIGS THAT DEVELOPED THIS MORNING HAS BURNED OFF AND VFR
CONDITIONS WL PREVAIL THROUGH 17Z. AFTN TSTM COVERAGE MAY BE A
LITTLE GREATER TODAY...POSSIBLY AFFECTING SITES FARTHER WEST
INCLUDING GLH/GWO/JAN/HKS. GTR/MEI/HBG/PIB CAN EXPECT TSTM COVERAGE
THIS AFTN TO BE SIMILAR TO WHAT HAS BEEN EXPERIENCED THE PAST FEW
DAYS. MAINLY VFR CONDITIONS WILL FOLLOW TODAY AND THROUGH MOST OF
TONIGHT BEFORE THE REDEVELOPMENT OF PATCHY AREAS OF FOG AND STRATUS
LATE TONIGHT INTO EARLY SATURDAY MORNING. /22/EC/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 95 73 94 73 / 37 20 29 17
MERIDIAN 93 73 94 71 / 44 25 30 13
VICKSBURG 96 74 95 71 / 26 18 30 18
HATTIESBURG 94 75 94 73 / 55 16 31 12
NATCHEZ 94 74 94 73 / 40 15 40 15
GREENVILLE 97 75 95 74 / 27 23 37 26
GREENWOOD 97 73 95 73 / 27 27 43 28
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...HEAT ADVISORY UNTIL 7 PM CDT SATURDAY FOR MSZ018-019-025-034-035-
040-041.
HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR MSZ026-027-036-042-
043-047>049-053-054-059>062.
LA...HEAT ADVISORY UNTIL 7 PM CDT SATURDAY FOR LAZ007>009-015.
HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR LAZ016-023>026.
AR...HEAT ADVISORY UNTIL 7 PM CDT SATURDAY FOR ARZ074-075.
&&
$$
17/22/EC/BK/
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
1027 AM CDT Fri Aug 9 2013
.SHORT TERM: (Through Late Tonight)
Issued at 1010 AM CDT Fri Aug 9 2013
Rain chances will increase through late morning as vort max currently
moving into southwest Missouri continues to move northeastward. Band
of showers and thunderstorms currently extending from west of Lake
of the Ozarks to southwest of Farmington is within an area of
decent low level moisture convergence underneath increasing ascent
ahead of the vort max. This forcing will continue primarily over
central and southern Missouri through this evening. Consequently,
I have increased rain chances along and south of I-70 the rest of
the day to account for this. The latest RAP runs show that the low
level moisture convergence will persist over southern Missouri
into the evening close to the front, so may need to up chances in
the southern CWA in later forecasts.
Britt
.LONG TERM: (Tonight through Thursday)
Issued at 312 AM CDT Fri Aug 9 2013
The synoptic pattern over s sections of the FA remains essentially
unchanged tonight through Saturday, as does the seemingly non-stop
threat of showers and thunderstorms over this area. As normal,
models solutions vary in specifics but there does seem to be some
consensus that forcing of low level jet will become focused over
sw MO late tonight and into Saturday morning, although jet is much
weaker than the past few nights. So, expecting yet another
thunderstorm cluster to develop over/advect into SW Missouri
overnight, and work east into S sections of our CWA late tonight
and Saturday morning. At this time not planning any hydro
headlines due to rather weak lift and since s sections of our CWA
have been spared the extreme rains that other parts of southern
Missouri has received; nonetheless, with pwats pushing 2 inches
and given the very effective rain producing capabilities of this
airmass we will certainly be monitoring this threat.
Meanwhile...southward push of surface ridge parked over upper
Mississippi Valley will allow cooler and more stable air to work
into n sections of the CWA later tonight and Saturday. Any storms
that do form in the unstable air over the north this afternoon should
dissipate this evening, with the more stable air limiting
development during the day on Saturday.
Have continued chance POPs over southern sections of the CWA on
Saturday night and Sunday with model consensus indicating some weak
WAA/lift persisting near the weakening baroclinicity.
Eastward progression of surface ridge will allow southerly flow, and
unstable air, to return to northern sections of the CWA by Monday.
This, combined with several shortwaves pushing into area on
persistent NW flow, should mean a threat of thunderstorms for most
of the area Monday and Monday night. However, consensus of medium
range solutions do lower heights over the Great Lakes and the East
Coast as we head into midweek, which should nudge the pesky
baroclinicity a bit more to the south and west, and allow high
pressure to backdoor cooler and more stable air into the region.
Hopefully, this will provide at least temporary respite from the
wet weather in those areas that have been hard hit by flooding
over this past week.
Truett
&&
.AVIATION: (For the 12z TAFs through 12z Saturday Morning)
Issued at 610 AM CDT Fri Aug 9 2013
The fog that was affecting metro area TAF sites at 12Z should
continue dissipating after sunrise with VFR conditions expected by
mid-morning. Isolated to scattered showers and thunderstorms are
possible this afternoon when an upper level disturbance interacts
with a stalled frontal boundary across southern MO/IL, but confidence
in precipitation occurring at any given terminal is too low to
include a mention in the 12Z TAFs.
Specifics for KSTL: Isolated to scattered showers and
thunderstorms are possible this afternoon, but confidence in
timing and location is too low to include it in the 12Z TAF. VFR
conditions are expected outside of any thunderstorms.
42
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1032 AM CDT FRI AUG 9 2013
.UPDATE...
ISSUED AT 1032 AM CDT FRI AUG 9 2013
DENSE FOG ADVISORY WAS ALLOWED TO EXPIRE BY 10 AM AS EXPECTED.
PLENTY OF MID-HIGH CLOUDS CONTINUE TO STREAM NORTH INTO ESPECIALLY
THE CENTRAL/EASTERN CWA FROM A SHORTWAVE TROUGH CENTERED OVER
SOUTHERN/EASTERN KS...AND THIS COULD VERY WELL CONTINUE TO PROMOTE
MOSTLY CLOUDY SKIES WELL INTO THE AFTERNOON HOURS ESPECIALLY EAST
OF HIGHWAY 281...WITH AREAS FARTHER WEST SEEING INCREASING
SUNSHINE. THIS COULD MESS WITH CURRENTLY-ADVERTISED HIGH TEMPS A
BIT AND KEEP SOME PLACES DOWN CLOSER TO 80 VERSUS MID-80S...BUT
WILL STAY THE COURSE FOR NOW AND TAKE ANOTHER LOOK AROUND MID-DAY.
PRECIP-WISE...SLASHED ALL MENTION OF RAIN THROUGH 18Z/1PM EXCEPT
FOR A SLIGHT CHANCE OF SPRINKLES IN OUR FAR SOUTHERN KS ZONES IN
CASE SOMETHING CAN WORK NORTH FROM THE MORE ORGANIZED ACTIVITY IN
CENTRAL KS. FOR THIS AFTERNOON...ODDS ARE PRETTY HIGH THAT THE
VAST MAJORITY OF THE CWA REMAINS DRY...BUT WITH A FAIRLY WEAKLY
CAPPED AIRMASS AND ROUGHLY 500-1000 J/KG 0-1 KM MIXED-LAYER CAPE
PROGGED TO BUILD PER THE LATEST RAP/NAM...HIGHEST IN THE
WEST...HELD ONTO A SLIGHT CHANCE OF SHOWERS/ISOLATED THUNDER THIS
AFTERNOON FOR ALL BUT THE FAR NORTHEASTERN FEW COUNTIES. AS HAS
BEEN THE CASE OF LATE...THIS MODEST CAPE IS DISTRIBUTED IN A
TALL/SKINNY PROFILE WITH MID LEVEL LAPSE RATES ONLY AROUND 6
C/KM...SO THIS SHOULD GREATLY MINIMIZE ANY SEVERE WEATHER
THREAT...ALONG WITH DEEP-LAYER SHEAR ONLY AROUND 20KT OR LESS.
UPDATE ISSUED AT 746 AM CDT FRI AUG 9 2013
THE DENSE FOG ADVISORY HAS BEEN EXPANDED TO INCLUDE SEVERAL MORE
NEBRASKA COUNTIES...BASICALLY EVERYBODY ALONG/SOUTH OF INTERSTATE
80 AND ALSO SHERMAN/HOWARD. AREA AIRPORT OBS AND NDOR WEBCAMS
CLEARLY REVEAL AT LEAST LOCALLY DENSE FOG HAS EXPANDED EASTWARD
INTO THE YORK/AURORA AREAS...AND ALSO AT LEAST INTO NORTHERN
PORTIONS OF COUNTIES BORDERING THE STATE LINE...AS EVIDENCED BY
THE WEB CAM NEAR CAMPBELL. ITS CERTAINLY NOT A SOLID BLANKET OF
DENSE FOG ACROSS THE ENTIRE EXPANDED ADVISORY AREA...BUT ENOUGH
TO JUSTIFY THE HEADLINE FOR THE MORNING COMMUTE. EXPECTING
VISIBILITY TO IMPROVE CONSIDERABLY BY THE 9-10 AM HOUR...AS
SUPPORTED BY THE LATEST HRRR VISIBILITY PROG.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 449 AM CDT FRI AUG 9 2013
MAIN CHALLENGE WILL BE DETERMINING CHANCES OF PRECIPITATION AND
DENSE FOG THIS MORNING. THE LARGE SCALE PATTERN INCLUDES AN UPPER
CLOSED LOW SOUTH OF HUDSON BAY WITH A TROUGH EXTENDING INTO THE
GREAT LAKES AND OHIO VALLEY AND ALSO A CLOSED OVER THE CALIFORNIA
COAST. SOME DENSE FOG HAS DEVELOPED AS A RESULT OF LOW DEWPOINT
DEPRESSIONS AND CALM WIND...PRIMARILY IN THE WEST CENTRAL
CWA...INCLUDING THE TRI- CITIES OF KEARNEY...HASTINGS...AND GRAND
ISLAND. THE FOG SHOULD BURN OFF BY MID-MORNING AS MIXING ENSUES. A
FRONTOLYTIC SURFACE BOUNDARY WILL CONTINUE TO SAG THROUGH THE
VICINITY OF THE CWA TODAY INTO THIS EVENING...WHICH WILL PROVIDE A
FOCUS FOR SOME CONVECTION...ALTHOUGH NOT A HUGE AMOUNT OF SUPPORT.
AS INSTABILITY DECREASES AFTER SUNSET...SO WILL THE SHOT AT SOME
ISOLATED CONVECTION. ALSO...IN THE SOUTHERN CWA...THIS AREA MAY BE
CLOSE ENOUGH TO BE IN A MID- LEVEL FRONTOGENETIC AREA FROM
ACTIVITY IN THE SOUTH TO GET SOME CONVECTION GOING. THERE WILL
PROBABLY NOT BE ENOUGH INSTABILITY FOR THUNDER UNTIL THIS
AFTERNOON AND EVENING...BUT NOT ENOUGH TO SUPPORT SEVERE WEATHER.
STILL GOING WITH HIGHS IN THE 80S WITH THE EXPECTATION OF SOME
SUNSHINE BREAKING OUT AND KEPT SIMILAR TEMPERATURES FROM THE
PREVIOUS FORECAST FOR LOWS TONIGHT. SOME FOG IS NOT OUT OF THE
QUESTION TONIGHT AS WIND WILL BE LIGHT ONCE AGAIN...WITH A SIMILAR
TEMPERATURE AND DEWPOINT SITUATION AS THIS MORNING.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 449 AM CDT FRI AUG 9 2013
MAIN FORECAST CONCERNS WILL BE CHANCES FOR THUNDERSTORMS AND
TEMPERATURES.
NORTHWEST FLOW WILL CONTINUE ACROSS THE AREA THROUGH THE PERIOD WITH
A SERIES OF UPPER LEVEL WAVES THAT MOVE THROUGH THE AREA AND BRING
MULTIPLE CHANCES FOR THUNDERSTORMS. MODELS CONTINUE TO BE SIMILAR IN
THE MAIN FEATURES...BUT THE DETAILS ARE A LITTLE DIFFERENT WITH EACH
MODEL.
SATURDAY WILL CONTINUE TO BE DRY SINCE WE WILL BE BETWEEN UPPER
LEVEL WAVES. THE FIRST WAVE TO MOVE THROUGH WILL MOVE INTO THE AREA
SATURDAY NIGHT. THERE IS A WEAK COLD FRONT ACROSS NORTHERN NEBRASKA
AND AS THE WAVE MOVES INTO THE AREA THUNDERSTORMS ARE EXPECTED TO
DEVELOP ALONG THE FRONT. THIS SHOULD KEEP THE PRECIPITATION CONFINED
TO THE NORTHERN PART OF THE FORECAST AREA.
SUNDAY AND SUNDAY NIGHT THE SURFACE COLD FRONT DRIFTS TO THE SOUTH
AND AS AN UPPER LEVEL WAVE MOVES THROUGH THE CHANCES FOR
THUNDERSTORMS SPREAD ACROSS THE AREA. SUNDAY NIGHT APPEARS AT THIS
TIME TO BE THE BEST CHANCE FOR THUNDERSTORMS ACROSS THE AREA. A FEW
THUNDERSTORMS COULD LINGER INTO MONDAY AS THE FRONT CONTINUES TO
MOVE TO THE SOUTH.
THE NEXT UPPER LEVEL WAVE WILL MOVE INTO THE AREA MONDAY NIGHT AND
TUESDAY. ONCE AGAIN THE BETTER CHANCE FOR THUNDERSTORMS WILL BE
DURING THE NIGHT TIME. THE PERIOD TUESDAY NIGHT THROUGH THURSDAY THE
MODELS HAVE A FEW MORE DIFFERENCES. WILL KEEP SOME MAINLY LOW
CHANCES FOR THUNDERSTORMS ACROSS THE AREA. EXPECT THAT ANY
THUNDERSTORMS WILL BE FAIRLY ISOLATED.
TEMPERATURES FOR SATURDAY AND SUNDAY WILL BE FAIRLY CLOSE TO NORMAL
FOR THIS TIME OF YEAR. WITH THE COLD FRONT MOVING THROUGH SUNDAY THE
TEMPERATURES ON MONDAY WILL BE A LITTLE COOLER. THE SLIGHTLY COOLER
TEMPERATURES WILL CONTINUE THROUGH THURSDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 551 AM CDT FRI AUG 9 2013
REDUCED VISIBILITY WILL BE THE BIGGEST ISSUE FOR THE FORECAST
THIS MORNING. SOME ISOLATED SHOWERS COULD OCCUR FOR THIS AFTERNOON
AND EVENING...BUT CHANCES ARE LOW ENOUGH TO NOT INCLUDE IN THE
FORECAST FOR NOW. MORE REDUCED VISIBILITY IS POSSIBLE FOR LATE
TONIGHT AGAIN...BUT PERHAPS NOT AS DENSE AS THIS MORNING.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...PFANNKUCH
SHORT TERM...HEINLEIN
LONG TERM...JCB
AVIATION...HEINLEIN
AREA FORECAST DISCUSSION
NWS HASTINGS NE
746 AM CDT FRI AUG 9 2013
.UPDATE...
ISSUED AT 746 AM CDT FRI AUG 9 2013
THE DENSE FOG ADVISORY HAS BEEN EXPANDED TO INCLUDE SEVERAL MORE
NEBRASKA COUNTIES...BASICALLY EVERYBODY ALONG/SOUTH OF INTERSTATE
80 AND ALSO SHERMAN/HOWARD. AREA AIRPORT OBS AND NDOR WEBCAMS
CLEARLY REVEAL AT LEAST LOCALLY DENSE FOG HAS EXPANDED EASTWARD
INTO THE YORK/AURORA AREAS...AND ALSO AT LEAST INTO NORTHERN
PORTIONS OF COUNTIES BORDERING THE STATE LINE...AS EVIDENCED BY
THE WEB CAM NEAR CAMPBELL. ITS CERTAINLY NOT A SOLID BLANKET OF
DENSE FOG ACROSS THE ENTIRE EXPANDED ADVISORY AREA...BUT ENOUGH
TO JUSTIFY THE HEADLINE FOR THE MORNING COMMUTE. EXPECTING
VISIBILITY TO IMPROVE CONSIDERABLY BY THE 9-10 AM HOUR...AS
SUPPORTED BY THE LATEST HRRR VISIBILITY PROG.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 449 AM CDT FRI AUG 9 2013
MAIN CHALLENGE WILL BE DETERMINING CHANCES OF PRECIPITATION AND
DENSE FOG THIS MORNING. THE LARGE SCALE PATTERN INCLUDES AN UPPER
CLOSED LOW SOUTH OF HUDSON BAY WITH A TROUGH EXTENDING INTO THE
GREAT LAKES AND OHIO VALLEY AND ALSO A CLOSED OVER THE CALIFORNIA
COAST. SOME DENSE FOG HAS DEVELOPED AS A RESULT OF LOW DEWPOINT
DEPRESSIONS AND CALM WIND...PRIMARILY IN THE WEST CENTRAL
CWA...INCLUDING THE TRI- CITIES OF KEARNEY...HASTINGS...AND GRAND
ISLAND. THE FOG SHOULD BURN OFF BY MID-MORNING AS MIXING ENSUES. A
FRONTOLYTIC SURFACE BOUNDARY WILL CONTINUE TO SAG THROUGH THE
VICINITY OF THE CWA TODAY INTO THIS EVENING...WHICH WILL PROVIDE A
FOCUS FOR SOME CONVECTION...ALTHOUGH NOT A HUGE AMOUNT OF SUPPORT.
AS INSTABILITY DECREASES AFTER SUNSET...SO WILL THE SHOT AT SOME
ISOLATED CONVECTION. ALSO...IN THE SOUTHERN CWA...THIS AREA MAY BE
CLOSE ENOUGH TO BE IN A MID- LEVEL FRONTOGENETIC AREA FROM
ACTIVITY IN THE SOUTH TO GET SOME CONVECTION GOING. THERE WILL
PROBABLY NOT BE ENOUGH INSTABILITY FOR THUNDER UNTIL THIS
AFTERNOON AND EVENING...BUT NOT ENOUGH TO SUPPORT SEVERE WEATHER.
STILL GOING WITH HIGHS IN THE 80S WITH THE EXPECTATION OF SOME
SUNSHINE BREAKING OUT AND KEPT SIMILAR TEMPERATURES FROM THE
PREVIOUS FORECAST FOR LOWS TONIGHT. SOME FOG IS NOT OUT OF THE
QUESTION TONIGHT AS WIND WILL BE LIGHT ONCE AGAIN...WITH A SIMILAR
TEMPERATURE AND DEWPOINT SITUATION AS THIS MORNING.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 449 AM CDT FRI AUG 9 2013
MAIN FORECAST CONCERNS WILL BE CHANCES FOR THUNDERSTORMS AND
TEMPERATURES.
NORTHWEST FLOW WILL CONTINUE ACROSS THE AREA THROUGH THE PERIOD WITH
A SERIES OF UPPER LEVEL WAVES THAT MOVE THROUGH THE AREA AND BRING
MULTIPLE CHANCES FOR THUNDERSTORMS. MODELS CONTINUE TO BE SIMILAR IN
THE MAIN FEATURES...BUT THE DETAILS ARE A LITTLE DIFFERENT WITH EACH
MODEL.
SATURDAY WILL CONTINUE TO BE DRY SINCE WE WILL BE BETWEEN UPPER
LEVEL WAVES. THE FIRST WAVE TO MOVE THROUGH WILL MOVE INTO THE AREA
SATURDAY NIGHT. THERE IS A WEAK COLD FRONT ACROSS NORTHERN NEBRASKA
AND AS THE WAVE MOVES INTO THE AREA THUNDERSTORMS ARE EXPECTED TO
DEVELOP ALONG THE FRONT. THIS SHOULD KEEP THE PRECIPITATION CONFINED
TO THE NORTHERN PART OF THE FORECAST AREA.
SUNDAY AND SUNDAY NIGHT THE SURFACE COLD FRONT DRIFTS TO THE SOUTH
AND AS AN UPPER LEVEL WAVE MOVES THROUGH THE CHANCES FOR
THUNDERSTORMS SPREAD ACROSS THE AREA. SUNDAY NIGHT APPEARS AT THIS
TIME TO BE THE BEST CHANCE FOR THUNDERSTORMS ACROSS THE AREA. A FEW
THUNDERSTORMS COULD LINGER INTO MONDAY AS THE FRONT CONTINUES TO
MOVE TO THE SOUTH.
THE NEXT UPPER LEVEL WAVE WILL MOVE INTO THE AREA MONDAY NIGHT AND
TUESDAY. ONCE AGAIN THE BETTER CHANCE FOR THUNDERSTORMS WILL BE
DURING THE NIGHT TIME. THE PERIOD TUESDAY NIGHT THROUGH THURSDAY THE
MODELS HAVE A FEW MORE DIFFERENCES. WILL KEEP SOME MAINLY LOW
CHANCES FOR THUNDERSTORMS ACROSS THE AREA. EXPECT THAT ANY
THUNDERSTORMS WILL BE FAIRLY ISOLATED.
TEMPERATURES FOR SATURDAY AND SUNDAY WILL BE FAIRLY CLOSE TO NORMAL
FOR THIS TIME OF YEAR. WITH THE COLD FRONT MOVING THROUGH SUNDAY THE
TEMPERATURES ON MONDAY WILL BE A LITTLE COOLER. THE SLIGHTLY COOLER
TEMPERATURES WILL CONTINUE THROUGH THURSDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 551 AM CDT FRI AUG 9 2013
REDUCED VISIBILITY WILL BE THE BIGGEST ISSUE FOR THE FORECAST
THIS MORNING. SOME ISOLATED SHOWERS COULD OCCUR FOR THIS AFTERNOON
AND EVENING...BUT CHANCES ARE LOW ENOUGH TO NOT INCLUDE IN THE
FORECAST FOR NOW. MORE REDUCED VISIBILITY IS POSSIBLE FOR LATE
TONIGHT AGAIN...BUT PERHAPS NOT AS DENSE AS THIS MORNING.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR NEZ046>048-
060>064-072>077-082>087.
KS...NONE.
&&
$$
UPDATE...PFANNKUCH
SHORT TERM...HEINLEIN
LONG TERM...JCB
AVIATION...HEINLEIN
AREA FORECAST DISCUSSION
NWS RALEIGH NC
650 AM EDT FRI AUG 9 2013
.SYNOPSIS...
HIGH PRESSURE OFF THE SOUTHEAST COAST WILL KEEP A MOIST AIR MASS IN
PLACE OVER THE CAROLINAS TODAY. A COLD FRONT WILL MOVE INTO THE
REGION THIS WEEKEND... THEN STALL OVER THE AREA INTO EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 300 AM FRIDAY...
THIS MORNING...
PATCHY CIRRUS IS MOSTLY DISSIPATING OVERHEAD...WITH PARTLY CLOUDY
SKIES OBSERVED OVER THE WESTERN CWA AND NEARLY CLEAR CONDITIONS OVER
THE EAST. A LIGHT SOUTHERLY WIND CONTINUES TO STIR OVER MUCH OF THE
CWA...BUT WHERE WINDS GO CALM...SOME PATCHY FOG MAY BE POSSIBLE
AROUND SUNRISE. THE HRRR ALSO SHOWS SOME SHOWERS DEVELOPING OVER
UPSTATE SC...DRIFTING NORTHEAST INTO THE WESTERN PIEDMONT. WHILE
SOME WEAK MUCAPE ANALYZED ON THE SPC MESO-ANALYSIS WOULD SUPPORT
THIS...THERE HAVE YET TO BE ANY SIGNS OF DEVELOPMENT ON REGIONAL
RADAR.
TODAY...
AS A COLD FRONT MOVES SLOWLY THROUGH THE OHIO VALLEY REGION
TODAY...THE DEEP LAYER FLOW AHEAD OF THE FRONT WILL BECOME MORE
UNIFORM AND SOUTHWESTERLY. THE UPPER LEVEL RIDGE TO OUR SOUTHWEST
WILL CAUSE A COUPLE CONVECTIVELY INDUCED DISTURBANCES UPSTREAM TO
SHEAR OUT AND DRIFT NORTHEAST TOWARD THE MID-ATLANTIC STATES TODAY.
THIS WILL LEAVE LOW-LEVEL CONVERGENCE IN THE FORM OF A
PREFRONTAL/LEE TROUGH AS THE MAIN TRIGGER FOR SCATTERED CONVECTION
THIS AFTERNOON. PW VALUES ARE RATHER HIGH...ABOVE 2 INCHES...BUT
MID-LEVEL LAPSE RATES ARE WEAK AND MLCAPE IS FORECAST TO REMAIN
AROUND 1000 J/KG AT BEST. MOST OF THE HI-RES MODELS SHOW
DEVELOPMENT GENERALLY FROM WINSTON-SALEM TO ROXBORO BY 20Z....WHERE
THE SFC TO 850MB CONVERGENCE IS STRONGEST....DRIFTING EAST THIS
EVENING BUT DYING OFF WITH LOSS OF HEATING. THE SEABREEZE SHOULD
ALSO BE ACTIVE AGAIN...THOUGH SOUTHWESTERLY LOW-LEVEL FLOW WOULD NOT
SUPPORT A STRONG INLAND PUSH.
REGARDING HIGHS...LOW-LEVEL THICKNESSES ARE FORECAST TO BE EQUAL TO
OR GREATER THAN OBSERVED VALUES ON THURSDAY...WHICH WOULD SUPPORT
LEANING TOWARD THE WARMER MAV MOS VALUES OF UPPER 80S AND LOWERS
90S. THIS IS ALSO BE SUPPORTED BY MORE WEST-SOUTHWESTERLY
PRE-FRONTAL FLOW WITH AT LEAST A WEAK DOWNSLOPE COMPONENT.
TONIGHT...
THE COLD FRONT WILL REMAIN TO OUR NORTH TONIGHT...AND INCREASINGLY
WESTERLY 850MB FLOW SHOULD HELP TO LIMIT ANY ADDITIONAL SHOWERS OR
STORMS OVERNIGHT. A CAVEAT TO THIS COULD BE OUTFLOW FROM STORMS TO
OUR NORTH...BUT HI-RES MODELS ARENT SHOWING VERY ROBUST CONVECTION
ALONG THE MAIN FRONTAL ZONE TODAY. THUS...EXPECT MOST OF THE NIGHT
TO BE DRY AFTER MIDNIGHT...WITH MUGGY LOWS IN THE LOWER 70S.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY NIGHT/...
AS OF 300 AM FRIDAY...
SATURDAY AND SATURDAY NIGHT...
THE COLD FRONT TO OUR NORTH IS FORECAST TO SLIDE SOUTH INTO NC AND
ESSENTIALLY STALL THROUGH THE WEEKEND. WITH HIGH PW VALUES AROUND 2
INCHES...MORE FOCUSED LOW-LEVEL CONVERGENCE...AND SLIGHTLY STRONGER
BUT BROAD CYCLONIC FLOW ALOFT...SHOWERS AND STORMS SHOULD BE MORE
NUMEROUS BY EARLY SATURDAY AFTERNOON. SREF PROBABILITIES INDICATE A
MUCH GREATER LIKELIHOOD OF MLCAPE ABOVE 1000 J/KG...AND WITH 25-30KT
OF 0-6KM BULK SHEAR...A FEW CLUSTERS OF STRONG STORMS WITH DAMAGING
WIND GUSTS WILL BE POSSIBLE. A GREATER THREAT MAY BE TRAINING OF
HEAVY DOWNPOURS AS THE STEERING FLOW BECOMES PARALLEL TO THE FRONT.
WILL CONTINUE WITH LIKELY POPS DURING THE DAY SATURDAY AND MAINTAIN
A CHANCE ON SATURDAY NIGHT GIVEN THAT THE FRONT AND VARIOUS OUTFLOW
BOUNDARIES WILL LINGER OVER THE CWA. THICKER CLOUD COVER AND
EARLIER CONVECTIVE INITIATION MAY HOLD TEMPS DOWN TO THE MID/UPPER
80S IN THE NORTH SATURDAY...WHILE LOWER 90S MAY BE MORE COMMON
ACROSS THE SOUTHERN PIEDMONT/COASTAL PLAIN AS THE 850MB THERMAL
RIDGE SHIFT SOUTH. SATURDAY NIGHT LOWS AGAIN IN THE LOWER 70S.
-SMITH
FOR SUNDAY/SUNDAY NIGHT: WILL BE TOUGH TO ESCAPE GETTING WET ON
SUNDAY. THE DIFFUSE FRONTAL ZONE IS LIKELY TO BE SITUATED FROM SE VA
ACROSS NW NC AND BACK NW THROUGH KY... WITH A PRECEDING TROUGH
THROUGH ERN AND SOUTH CENTRAL NC (POTENTIALLY REINFORCED BY
CONVECTIVE OUTFLOW)... WHILE MID LEVEL LONGWAVE TROUGH AMPLIFIES
SLIGHTLY THROUGH SUNDAY NIGHT. DYNAMIC FORCING FOR ASCENT IS WEAK
BUT EVIDENT AT THE MID-UPPER LEVELS... INCLUDING UPPER DIVERGENCE IN
THE RIGHT ENTRANCE REGION OF THE WEAKENING 80 KT WESTERLY JET TO OUR
NE... SUBTLE DPVA WITH ONE WEAK MIDLEVEL WAVE SKIRTING ACROSS VA/NRN
NC SUNDAY... AND 20-30 METER MIDLEVEL HEIGHT FALLS. BUT THE SOMEWHAT
WEAK AND LARGELY WESTERLY LOW LEVEL WIND FIELD SUGGESTS THAT LIFT
ROOTED IN THE LOWER LEVELS MAY BE LIMITED TO SURFACE CONVERGENCE
ALONG THE TROUGH. DEEP LAYER BULK SHEAR IS MARGINAL AT AROUND 20-25
KTS (HIGHEST NORTH) THROUGH MUCH OF SUNDAY/SUNDAY NIGHT... BUT WITH
MLCAPE PROJECTED TO PEAK AT 1200-2000 J/KG (LOWEST NW AND HIGHEST
SE) AND CAPE IN THE MIXED-PHASE REGION TOPPING OUT AT A FAIRLY
RESPECTABLE 500-900 J/KG... A FEW STORMS COULD BECOME STRONG WITH A
RISK OF HAIL. HEAVY RAINERS AND TRAINING/SLOW-MOVING CELLS WILL ALSO
BRING ABOUT A RISK OF LOCALIZED FLOODING GIVEN PW VALUES HOLDING
AROUND 2 INCHES... AND THE WESTERLY FLOW AND HINTS AT AN INVERTED-V
PROFILE INDICATE POSSIBLE STRONG WIND GUSTS AS WELL. BELIEVE WE`LL
SEE GOOD COVERAGE OF CONVECTION EARLY ACROSS THE NORTH... RISING TO
LIKELY AND TRANSLATING SLOWLY TO THE SOUTHEAST THROUGH THE AFTERNOON
AND EVENING... BEFORE TRENDING OUT OF ALL BUT THE FAR EASTERN CWA
OVERNIGHT. HIGHS 86-91 AND LOWS 68-73.
FOR MONDAY/MONDAY NIGHT: THE SURFACE FRONT IS LIKELY TO BECOME EVEN
WEAKER AND MORE DIFFUSE OVER THE REGION MONDAY... AS IT WAITS FOR A
SECOND STRONGER COLD FRONT (ASSOCIATED WITH THE MID LEVEL SHORTWAVE
TROUGH SWINGING THROUGH SRN ONTARIO/SW QUEBEC) TO PUSH SOUTHEASTWARD
THROUGH THE GREAT LAKES/OH VALLEY TOWARD NC. WE MAY SEE ANOTHER
EARLY START TO CONVECTION ALONG THE DYING TROUGH OVER THE
CAROLINAS... AS THE GFS DEPICTS 18Z MLCAPE OF 2000-2500 J/KG AND
-10C TO -30C CAPE REACHING 1000 J/KG AREAWIDE. WHILE DYNAMIC FORCING
FOR LIFT LOOKS EVEN WEAKER MONDAY THAN ON SUNDAY... THE HIGH PW
VALUES ALONG WITH FAVORABLE THERMODYNAMICS AND THE PRESENCE OF A LOW
LEVEL FOCUS SUGGEST WE SHOULD SEE AT LEAST 50-60% COVERAGE OF
SHOWERS/STORMS IN THE AFTERNOON... PARTICULARLY OVER THE CENTRAL AND
SE PORTIONS OF THE FORECAST AREA... WINDING DOWN AS WE HEAD THROUGH
THE EVENING WITH LOSS OF HEATING AND SUBSEQUENT STABILIZATION.
MODELS DIFFER WIDELY ON THICKNESSES... LIKELY DUE IN PART TO
DIFFERENCES IN CLOUD COVER AND PRECIP COVERAGE... BUT GIVEN
EXPECTATIONS OF DECENT MID LEVEL CLOUD COVER THROUGH THIS TIME FRAME
AND POSSIBLE EARLY CONVECTION... WILL HOLD HIGH TEMPS A BIT BELOW
NORMAL... 85-89... WITH NEAR NORMAL LOWS OF 69-73. -GIH
&&
.LONG TERM /TUESDAY THROUGH THURSDAY/...
AS OF 310 AM FRIDAY...
EXPECT CONTINUED ABOVE-NORMAL RAIN CHANCES INTO WEDNESDAY...
FOLLOWED BY DRIER AND COOLER (POTENTIALLY MUCH SO) CONDITIONS FOR
THURSDAY. MODELS DIG THE MIDLEVEL TROUGH DOWN WELL INTO THE EASTERN
CONUS TUESDAY INTO WEDNESDAY... WITH THE SURFACE COLD FRONT PUSHING
TO OUR SOUTH WEDNESDAY. THEY THEN DEPICT THE DEVELOPMENT OF COLD AIR
DAMMING LATE WEDNESDAY AS THE SURFACE FRONT PUSHES JUST TO OUR
SOUTH WHILE CANADIAN HIGH PRESSURE SLIDES BY TO OUR NORTH... ACROSS
THE GREAT LAKES/OH VALLEY TO THE MIDATLANTIC/NORTHEAST. THE
AGREEMENT AMONG THE GFS/ECMWF/CANADIAN REGARDING THIS EVOLUTION IS
ACTUALLY FAIRLY GOOD CONSIDERING IT IS DAYS 5-7 OF THE FORECAST.
WILL KEEP A GOOD CHANCE OF SHOWERS/STORMS (HIGHER SOUTH/EAST)
TUESDAY INTO WEDNESDAY WITH TEMPS TRENDING FROM NEAR NORMAL TO JUST
BELOW NORMAL... THEN WILL GO LARGELY DRY THURSDAY BUT WITH LINGERING
CLOUD COVER AS 850 MB OVERRUNNING FLOW SHOULD RESUME BY LATE IN THE
DAY. GFS/ECMWF THICKNESSES PLUNGE TO AROUND 30 METERS BELOW NORMAL
THURSDAY... SUGGESTING HIGHS OF 77-83. -GIH
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
AS OF 650 AM FRIDAY...
A NARROW OF REGION OF STRATUS HAS FORMED OVER THE COASTAL
PLAIN...STRETCHING FROM KFAY TO KRWI IS SLOWLY EXPANDING TO THE
NORTHWEST. EXPECT IFR CEILINGS TO PERSIST AT KFAY AND KRWI THROUGH
AROUND 13Z...BUT IT DOES NOT APPEAR THESE CEILINGS WILL MAKE IT ALL
THE WAY TO KRDU BEFORE DAYTIME MIXING BEGINS TO ERODE THE STRATUS.
OTHERWISE...A FEW SITES ARE REPORTING MVFR VSBYS...INCLUDING KINT.
THESE CONDITIONS WILL ALSO IMPROVE RAPIDLY AFTER 12Z.
THIS AFTERNOON...SCATTERED SHOWERS AND STORMS SHOULD DEVELOP BY
18-20Z. HI-RES MODELS SHOW CONVECTIVE DEVELOPMENT OVER THE HIGHER
TERRAIN...EVENTUALLY MOVING INTO THE NORTHWEST PIEDMONT AND
IMPACTING KGSO AND KINT. WHILE THE STORMS ARE NOT EXPECTED TO BE
SEVERE...STRONG WIND GUSTS AND BRIEF IFR/LIFR CONDITIONS WILL BE
POSSIBLE.
THE LOSS OF HEATING SHOULD BRING ALL SHOWER AND STORMS TO AN END
THIS EVENING...WITH JUST A LIGHT SOUTHWESTERLY WIND OVERNIGHT.
STRATUS WILL BE POSSIBLE AGAIN LATE TONIGHT...ALTHOUGH WITH MORE OF
A WEST-SOUTHWESTERLY WIND...LOW CEILINGS MAY AGAIN BE CONFINED TO
THE COASTAL PLAIN.
OUTLOOK...
A COLD FRONT WILL MOVE SOUTH INTO VIRGINIA AND THE CAROLINAS OVER
THE WEEKEND...EVENTUALLY STALLING AND LINGERING THROUGH EARLY NEXT
WEEK. THIS WILL BRING AN EXTENDED PERIOD OF UNSETTLED WEATHER WITH
ABOVE AVERAGE CHANCES OF SHOWERS AND STORMS.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...SMITH
NEAR TERM...SMITH
SHORT TERM..SMITH/HARTFIELD
LONG TERM...HARTFIELD
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
655 AM EDT FRI AUG 9 2013
.SYNOPSIS...
HIGH PRESSURE WILL SLOWLY GIVE WAY TO A MORE UNSETTLED PATTERN FOR
THE NEXT SEVERAL DAYS. GENEROUS AMOUNTS OF RAINFALL ARE POSSIBLE
SUNDAY THROUGH MUCH OF NEXT WEEK. A COLD FRONT MAY MOVE FAR ENOUGH
SOUTH LATE NEXT WEEK TO LEAD TO DRIER CONDITIONS.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM FRIDAY...THE MOST RECENT HRRR RUNS ARE NOT INITIALIZING
WITH ANY OF THE OBSERVED SHOWER ACTIVITY ALONG THE CAROLINA COAST.
FOR THE NEXT SEVERAL HOURS I EXPECT TO SEE A CONTINUATION OF
SCATTERED SHOWERS DEVELOPING ALONG THE SC LANDBREEZE FRONT...MOVING
NORTHEASTWARD WITH THE MEAN LOW LEVEL FLOW. OVER LAND THE BEST
POTENTIAL FOR ADDITIONAL RAINFALL WILL BE THE SOUTHPORT/BALD HEAD
ISLAND VICINITY...WITH A SECOND BATCH OF SHOWERS RECENTLY OBSERVED
DEVELOPING JUST SOUTHWEST OF GEORGETOWN WHICH COULD AFFECT COASTAL
SOUTH CAROLINA IF THEY HOLD TOGETHER. NO CHANGES IN THINKING FOR THE
AFTERNOON AS THE SEABREEZE SHOULD DRIVE MOST OF THE PRECIPITATION
INLAND FROM THE BEACHES. PREVIOUS DISCUSSION FROM 300 AM FOLLOWS...
SURFACE HIGH PRESSURE OFF THE U.S. EAST COAST IS DRAWING HOT
TROPICAL AIR NORTHWARD FROM THE CARIBBEAN. THE SUBTROPICAL RIDGE AT
500 THROUGH 200 MB IS NEARLY OVERHEAD AS A WELL-DEFINED TUTT LOW
MOVES WESTWARD UNDER THE RIDGE ACROSS THE FLORIDA KEYS. 850 MB
TEMPERATURES HAVE WARMED ALMOST ANOTHER FULL DEGREE CELSIUS FROM
YESTERDAY WHICH SHOULD GUARANTEE 91-93 ACROSS MOST OF THE INTERIOR
EASTERN CAROLINAS...WITH 88-90 EXPECTED NEAR THE COAST. IT IS WORTH
NOTING THAT THE MARINE ENVIRONMENT IS RIGHT AT ITS PEAK
CLIMATOLOGICAL TEMPERATURES OF THE YEAR AS MEASURED BY SEA SURFACE
AND AIR TEMPERATURE...SO THE COOLING EFFECT PROVIDED BY THE
SEABREEZE HAS REACHED ITS MINIMUM.
STEADY SOUTH-SOUTHWEST WINDS HAVE BEEN BLOWING ALONG THE COAST ALL
MORNING. AS A LANDBREEZE DEVELOPS BETWEEN GEORGETOWN AND SOUTHPORT
AND INTERCEPTS THIS WARM AND HUMID LOW-LEVEL AIRSTREAM...EXPECT A
LINE OF TOWERING CUMULUS AND EVENTUALLY SHOWERS DEVELOP AROUND OR
SHORTLY AFTER DAYBREAK. THE LAST SEVERAL RUNS OF THE HRRR DEPICT
THIS CONVECTION MAINLY REMAINING OFFSHORE...BUT IMPACTING AT LEAST
PORTIONS OF BRUNSWICK AND NEW HANOVER COUNTIES BETWEEN 8-11 AM. AS
HEAT AND HUMIDITY BUILD INLAND LOOK FOR SCATTERED SHOWERS AND
THUNDERSTORMS TO DEVELOP ALONG AND AHEAD OF THE SEABREEZE BOUNDARY
BEGINNING BY NOON. COVERAGE SHOULD AVERAGE ABOUT 30 PERCENT OF THE
AREA DURING THE DAYLIGHT HOURS...AIDED BY STORM MOTION TOWARD THE
NORTHEAST AT 12-15 MPH AND VERY LITTLE CONVECTIVE CAPPING WITHIN AN
AIRMASS CHARACTERIZED BY CAPE 1000-1500 J/KG. THESE SHOULD BE PULSE
STORMS WITH NO SIGNIFICANT WIND OR DRY LAYERS ALOFT AND PRECIPITABLE
WATER AROUND 2.0 INCHES.
CONVECTION SHOULD FALL APART DURING THE EARLY TO MID EVENING HOURS
WITH THE LOSS OF DAYTIME HEATING. MOSTLY CLEAR SKIES ARE EXPECTED
OVERNIGHT WITH LOWS FALLING TO 73-77...WARMEST ALONG THE SOUTH-
FACING BRUNSWICK COUNTY BEACHES.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 300 AM FRIDAY...MID LEVEL RIDGE WILL SLOWLY WEAKEN THROUGH THE
PERIOD AS THE TROPOSPHERE GRADUALLY BECOMES MORE CONDUCIVE FOR
CONVECTION. AT THE SURFACE...TOUGH TO DISTINGUISH BETWEEN AN ACTUAL
FRONT OR TROUGH BUT THE FOCUS WILL BE THE IMPORTANT FACTOR.
NUMERICAL GUIDANCE REFLECTS THIS TREND WITH SLOWLY INCREASING POPS
FROM SATURDAY MORNING THROUGH SUNDAY AFTERNOON. THE OFFICIAL
FORECAST SHOWS THIS AS WELL WITH POPS INITIALLY AT SLIGHT CHANCE
TRENDING UP TO GOOD CHANCE BY SUNDAY PM. PRECIPITABLE WATER VALUES
CLIMB FROM APPROXIMATELY 1.75 INCHES SATURDAY TO NEAR 2.00 INCHES
SUNDAY.
SOME MINOR DISAGREEMENT BETWEEN THE MAV AND MET NUMBERS FOR HIGH
TEMPERATURES ESPECIALLY INLAND. WILL LEAN TOWARD THE WARMER MAV
NUMBERS SATURDAY AND SLIGHTLY COOLER MET NUMBERS SUNDAY.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 300 AM FRIDAY...MEDIUM RANGE GUIDANCE CONTINUES TO DEPICT AN
EXTENDED PERIOD OF WET WEATHER AS TROUGHING IS IN PLACE ACROSS THE
MIDWEST AND RIDGING OUT WEST. THERE IS A SIGNAL THAT THE FRONT MAY
SLIP FAR ENOUGH SOUTH VIA THE PREFERRED ECMWF ENSEMBLE MEAN SOLUTION
FROM WPC THAT THURSDAY COULD DRY OUT A BIT. THIS IS REFLECTED IN
GRAPHICS FROM WPC AND IN OUR OFFICIAL FORECAST. WE ARE FORECASTING
HIGH CHANCE POPS AND EVEN A PERIOD...TUESDAY...OF LIKELY POPS WHICH
SEEM WARRANTED. AS MENTIONED LAST NIGHT...I BELIEVE THERE WILL BE
MORE LIKELY POPS WARRANTED AS WE DRAW CLOSER TO THE ONSET OF THE
EVENT. TEMPERATURE TRENDS REMAIN INTACT WITH DAYTIME
HIGHS...CERTAINLY MODULATED BY RAINFALL NEAR CLIMATOLOGY AND
OVERNIGHT LOWS A BIT ON THE HIGH SIDE CITING THE PREVAILING
MOISTURE.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
AS OF 12Z...A BIT OF A CONVERGENCE BOUNDARY WITH A WEAK LAND BREEZE
THIS MORNING. SCATTERED CONVECTION WILL OCCUR ALONG THIS BOUNDARY
THIS MORNING AS IT TRANSITIONS TO A SEA BREEZE BY LATE MORNING. A
SOUTH SOUTHWEST GRADIENT WILL CREATE GUSTY WINDS BY MIDDAY. THIS
AFTERNOON...THE PIEDMONT THERMAL TROUGH WILL SET UP...WITH SCATTERED
CONVECTION EXPECTED MAINLY DOWN THE I-95 CORRIDOR.
EXTENDED OUTLOOK...ISOLATED AFTERNOON SHOWERS AND THUNDERSTORMS
POSSIBLE THURSDAY THROUGH SATURDAY...BECOMING SCATTERED SUNDAY
THROUGH TUESDAY...OTHERWISE EXPECT VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM FRIDAY...SHOWER ACTIVITY GOT OFF TO AN EARLIER THAN
EXPECTED START...BUT THE REMAINDER OF THE FORECAST IS NEARLY
UNCHANGED. THE BULK OF THE SHOWERS SHOULD WRAP UP BY LATE MORNING AS
THE FOCUS FOR NEW CONVECTIVE DEVELOPMENT SHIFTS INLAND WITH THE
DEVELOPING SEABREEZE CIRCULATION. SEAS BUILT TO 3 FT RECENTLY AT
BOTH THE WILMINGTON HARBOR BUOY JUST SOUTH OF SOUTHPORT...AND AT THE
OCEAN CREST PIER WAVE GAUGE ON OAK ISLAND. I HAVE BUMPED UP THE
ONSET OF 3 FOOT SEAS BY A FEW HOURS TO MATCH OBSERVATIONS. PREVIOUS
DISCUSSION FROM 300 AM FOLLOWS...
HIGH PRESSURE OFF THE U.S. EAST COAST WILL MAINTAIN A
SOUTH-SOUTHWEST WIND ACROSS THE AREA TODAY AND TONIGHT. HIGH
RESOLUTION MODELS INDICATE A LANDBREEZE MAY DEVELOP ALONG THE SOUTH
CAROLINA COAST AROUND DAYBREAK...POTENTIALLY IGNITING SCATTERED
SHOWERS AND EMBEDDED THUNDERSTORMS DURING THE MORNING HOURS. RADAR
IS CURRENTLY CLEAR...BUT THIS PATTERN OF AN EARLY MORNING LANDBREEZE
LEADING TO SHOWERS IS A TYPICAL AUGUST WEATHER SCENARIO HERE. AS
HEAT BUILDS INLAND DURING THE LATE MORNING AND AFTERNOON HOURS MOST
OF THE SHOWER ACTIVITY OVER THE OCEAN SHOULD DISSIPATE WITH A MODEST
SEABREEZE INCREASING WIND SPEEDS TO 15 KNOTS NEAR SHORE. FOR TONIGHT
SHOWER CHANCES APPEAR QUITE LOW AS SOUTH-SOUTHWEST WINDS RETURN TO A
STEADY 10-15 KNOTS.
SEAS CURRENTLY AVERAGE 2 FT NEARSHORE WITH 2.5 TO 3 FOOT SEAS
REPORTED FROM THE FRYING PAN SHOALS BUOY. SEAS SHOULD AVERAGE 2-3 FT
THROUGH TONIGHT IN A COMBINATION OF 4 SECOND WIND WAVE AND 9 SECOND
SOUTHEAST SWELL.
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 300 AM FRIDAY...A RELATIVELY WEAK FRONT OR SURFACE TROUGH WILL
REMAIN INLAND ALLOWING A PERSISTENT SOUTHWEST FLOW TO CONTINUE
THOUGH THE PERIOD. WIND SPEEDS WILL BE 10-15 KNOTS. IT APPEARS THERE
IS A LITTLE ENHANCEMENT OF THE LOW LEVEL WIND FIELDS OVERNIGHT
SATURDAY INTO SUNDAY MORNING WHICH WILL TILT THE SPEEDS TO THE
HIGHER END OF THE RANGE. SIGNIFICANT SEAS REMAIN UNCHANGED WITH 2-3
FEET SHORTER PERIOD WIND WAVES.
LONG TERM /MONDAY THROUGH TUESDAY/...
AS OF 300 AM FRIDAY...DIFFUSE FRONT DRAPED ACROSS THE AREA WILL NOT
HAVE A SIGNIFICANT IMPACT ON THE COASTAL WATERS FORECAST AT LEAST
FROM A SYNOPTIC STANDPOINT. SOUTHWEST WINDS OF AROUND TEN KNOTS WILL
PREVAIL WITH SIGNIFICANT SEAS OF 2-4 FEET. THE WAVEWATCH GUIDANCE IS
TRENDING UP FROM 2-3 FEET MONDAY TO 2-4 FEET TUESDAY MAINLY ACROSS
THE OUTER WATERS. PERIODS SHOW WIND WAVES WHICH GIVES ME PAUSE AS
THE WIND FIELDS REMAIN WEAK BUT THE INCREASE ISN/T A SIGNIFICANT
IMPACT ON THE FORECAST.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...SHK
NEAR TERM...TRA
SHORT TERM...SHK
LONG TERM...SHK
AVIATION...43
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
642 AM EDT FRI AUG 9 2013
.SYNOPSIS...
HIGH PRESSURE WILL SLOWLY GIVE WAY TO A MORE UNSETTLED PATTERN FOR
THE NEXT SEVERAL DAYS. GENEROUS AMOUNTS OF RAINFALL ARE POSSIBLE
SUNDAY THROUGH MUCH OF NEXT WEEK. A COLD FRONT MAY MOVE FAR ENOUGH
SOUTH LATE NEXT WEEK TO LEAD TO DRIER CONDITIONS.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM FRIDAY...THE MOST RECENT HRRR RUNS ARE NOT INITIALIZING
WITH ANY OF THE OBSERVED SHOWER ACTIVITY ALONG THE CAROLINA COAST.
FOR THE NEXT SEVERAL HOURS I EXPECT TO SEE A CONTINUATION OF
SCATTERED SHOWERS DEVELOPING ALONG THE SC LANDBREEZE FRONT...MOVING
NORTHEASTWARD WITH THE MEAN LOW LEVEL FLOW. OVER LAND THE BEST
POTENTIAL FOR ADDITIONAL RAINFALL WILL BE THE SOUTHPORT/BALD HEAD
ISLAND VICINITY...WITH A SECOND BATCH OF SHOWERS RECENTLY OBSERVED
DEVELOPING JUST SOUTHWEST OF GEORGETOWN WHICH COULD AFFECT COASTAL
SOUTH CAROLINA IF THEY HOLD TOGETHER. NO CHANGES IN THINKING FOR THE
AFTERNOON AS THE SEABREEZE SHOULD DRIVE MOST OF THE PRECIPITATION
INLAND FROM THE BEACHES. PREVIOUS DISCUSSION FROM 300 AM FOLLOWS...
SURFACE HIGH PRESSURE OFF THE U.S. EAST COAST IS DRAWING HOT
TROPICAL AIR NORTHWARD FROM THE CARIBBEAN. THE SUBTROPICAL RIDGE AT
500 THROUGH 200 MB IS NEARLY OVERHEAD AS A WELL-DEFINED TUTT LOW
MOVES WESTWARD UNDER THE RIDGE ACROSS THE FLORIDA KEYS. 850 MB
TEMPERATURES HAVE WARMED ALMOST ANOTHER FULL DEGREE CELSIUS FROM
YESTERDAY WHICH SHOULD GUARANTEE 91-93 ACROSS MOST OF THE INTERIOR
EASTERN CAROLINAS...WITH 88-90 EXPECTED NEAR THE COAST. IT IS WORTH
NOTING THAT THE MARINE ENVIRONMENT IS RIGHT AT ITS PEAK
CLIMATOLOGICAL TEMPERATURES OF THE YEAR AS MEASURED BY SEA SURFACE
AND AIR TEMPERATURE...SO THE COOLING EFFECT PROVIDED BY THE
SEABREEZE HAS REACHED ITS MINIMUM.
STEADY SOUTH-SOUTHWEST WINDS HAVE BEEN BLOWING ALONG THE COAST ALL
MORNING. AS A LANDBREEZE DEVELOPS BETWEEN GEORGETOWN AND SOUTHPORT
AND INTERCEPTS THIS WARM AND HUMID LOW-LEVEL AIRSTREAM...EXPECT A
LINE OF TOWERING CUMULUS AND EVENTUALLY SHOWERS DEVELOP AROUND OR
SHORTLY AFTER DAYBREAK. THE LAST SEVERAL RUNS OF THE HRRR DEPICT
THIS CONVECTION MAINLY REMAINING OFFSHORE...BUT IMPACTING AT LEAST
PORTIONS OF BRUNSWICK AND NEW HANOVER COUNTIES BETWEEN 8-11 AM. AS
HEAT AND HUMIDITY BUILD INLAND LOOK FOR SCATTERED SHOWERS AND
THUNDERSTORMS TO DEVELOP ALONG AND AHEAD OF THE SEABREEZE BOUNDARY
BEGINNING BY NOON. COVERAGE SHOULD AVERAGE ABOUT 30 PERCENT OF THE
AREA DURING THE DAYLIGHT HOURS...AIDED BY STORM MOTION TOWARD THE
NORTHEAST AT 12-15 MPH AND VERY LITTLE CONVECTIVE CAPPING WITHIN AN
AIRMASS CHARACTERIZED BY CAPE 1000-1500 J/KG. THESE SHOULD BE PULSE
STORMS WITH NO SIGNIFICANT WIND OR DRY LAYERS ALOFT AND PRECIPITABLE
WATER AROUND 2.0 INCHES.
CONVECTION SHOULD FALL APART DURING THE EARLY TO MID EVENING HOURS
WITH THE LOSS OF DAYTIME HEATING. MOSTLY CLEAR SKIES ARE EXPECTED
OVERNIGHT WITH LOWS FALLING TO 73-77...WARMEST ALONG THE SOUTH-
FACING BRUNSWICK COUNTY BEACHES.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 300 AM FRIDAY...MID LEVEL RIDGE WILL SLOWLY WEAKEN THROUGH THE
PERIOD AS THE TROPOSPHERE GRADUALLY BECOMES MORE CONDUCIVE FOR
CONVECTION. AT THE SURFACE...TOUGH TO DISTINGUISH BETWEEN AN ACTUAL
FRONT OR TROUGH BUT THE FOCUS WILL BE THE IMPORTANT FACTOR.
NUMERICAL GUIDANCE REFLECTS THIS TREND WITH SLOWLY INCREASING POPS
FROM SATURDAY MORNING THROUGH SUNDAY AFTERNOON. THE OFFICIAL
FORECAST SHOWS THIS AS WELL WITH POPS INITIALLY AT SLIGHT CHANCE
TRENDING UP TO GOOD CHANCE BY SUNDAY PM. PRECIPITABLE WATER VALUES
CLIMB FROM APPROXIMATELY 1.75 INCHES SATURDAY TO NEAR 2.00 INCHES
SUNDAY.
SOME MINOR DISAGREEMENT BETWEEN THE MAV AND MET NUMBERS FOR HIGH
TEMPERATURES ESPECIALLY INLAND. WILL LEAN TOWARD THE WARMER MAV
NUMBERS SATURDAY AND SLIGHTLY COOLER MET NUMBERS SUNDAY.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 300 AM FRIDAY...MEDIUM RANGE GUIDANCE CONTINUES TO DEPICT AN
EXTENDED PERIOD OF WET WEATHER AS TROUGHING IS IN PLACE ACROSS THE
MIDWEST AND RIDGING OUT WEST. THERE IS A SIGNAL THAT THE FRONT MAY
SLIP FAR ENOUGH SOUTH VIA THE PREFERRED ECMWF ENSEMBLE MEAN SOLUTION
FROM WPC THAT THURSDAY COULD DRY OUT A BIT. THIS IS REFLECTED IN
GRAPHICS FROM WPC AND IN OUR OFFICIAL FORECAST. WE ARE FORECASTING
HIGH CHANCE POPS AND EVEN A PERIOD...TUESDAY...OF LIKELY POPS WHICH
SEEM WARRANTED. AS MENTIONED LAST NIGHT...I BELIEVE THERE WILL BE
MORE LIKELY POPS WARRANTED AS WE DRAW CLOSER TO THE ONSET OF THE
EVENT. TEMPERATURE TRENDS REMAIN INTACT WITH DAYTIME
HIGHS...CERTAINLY MODULATED BY RAINFALL NEAR CLIMATOLOGY AND
OVERNIGHT LOWS A BIT ON THE HIGH SIDE CITING THE PREVAILING
MOISTURE.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
AS OF 06Z...A SOUTHWEST LOW LEVEL JET WITH 1000 FT AGL WIND SPEEDS
NEAR 20 KNOTS SHOULD PREVENT FOG FORMATION THROUGH DAYBREAK...BUT
COULD ACTUALLY FAVOR LOW STRATUS DEVELOPMENT INLAND. GFS AND NAM MOS
BOTH SHOW THIS POTENTIAL AT FLO AND LBT...BUT AFTER LAST NIGHT`S
BUST WITH IFR CONDITIONS FORECAST BUT NEVER OCCURRING I AM NOT SO
CERTAIN. FOR NOW I WILL ONLY INCLUDE SCATTERED LOW CLOUDS IN THE
FORECAST...BUT BE AWARE THERE IS SOME POTENTIAL FOR AN HOUR OR TWO
OF IFR CEILINGS AT BOTH FLO AND LBT...MAINLY 10-12Z.
AFTER DAYBREAK...SCATTERED CUMULUS WITH BASES 2000-3000 FT AGL
SHOULD DEVELOP WITH MODERATE SOUTHWEST LOW LEVEL WINDS GUSTING AS
HIGH AS 20 KNOTS AT THE COAST. MUCH LIKE YESTERDAY SCATTERED SHOWERS
MAY DEVELOP FIRST IN THE WILMINGTON AREA...SPREADING INLAND WITH THE
AFTERNOON SEABREEZE.
EXTENDED OUTLOOK...ISOLATED AFTERNOON SHOWERS AND THUNDERSTORMS
POSSIBLE THURSDAY THROUGH SATURDAY...BECOMING SCATTERED SUNDAY
THROUGH TUESDAY...OTHERWISE EXPECT VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM FRIDAY...SHOWER ACTIVITY GOT OFF TO AN EARLIER THAN
EXPECTED START...BUT THE REMAINDER OF THE FORECAST IS NEARLY
UNCHANGED. THE BULK OF THE SHOWERS SHOULD WRAP UP BY LATE MORNING AS
THE FOCUS FOR NEW CONVECTIVE DEVELOPMENT SHIFTS INLAND WITH THE
DEVELOPING SEABREEZE CIRCULATION. SEAS BUILT TO 3 FT RECENTLY AT
BOTH THE WILMINGTON HARBOR BUOY JUST SOUTH OF SOUTHPORT...AND AT THE
OCEAN CREST PIER WAVE GAUGE ON OAK ISLAND. I HAVE BUMPED UP THE
ONSET OF 3 FOOT SEAS BY A FEW HOURS TO MATCH OBSERVATIONS. PREVIOUS
DISCUSSION FROM 300 AM FOLLOWS...
HIGH PRESSURE OFF THE U.S. EAST COAST WILL MAINTAIN A
SOUTH-SOUTHWEST WIND ACROSS THE AREA TODAY AND TONIGHT. HIGH
RESOLUTION MODELS INDICATE A LANDBREEZE MAY DEVELOP ALONG THE SOUTH
CAROLINA COAST AROUND DAYBREAK...POTENTIALLY IGNITING SCATTERED
SHOWERS AND EMBEDDED THUNDERSTORMS DURING THE MORNING HOURS. RADAR
IS CURRENTLY CLEAR...BUT THIS PATTERN OF AN EARLY MORNING LANDBREEZE
LEADING TO SHOWERS IS A TYPICAL AUGUST WEATHER SCENARIO HERE. AS
HEAT BUILDS INLAND DURING THE LATE MORNING AND AFTERNOON HOURS MOST
OF THE SHOWER ACTIVITY OVER THE OCEAN SHOULD DISSIPATE WITH A MODEST
SEABREEZE INCREASING WIND SPEEDS TO 15 KNOTS NEAR SHORE. FOR TONIGHT
SHOWER CHANCES APPEAR QUITE LOW AS SOUTH-SOUTHWEST WINDS RETURN TO A
STEADY 10-15 KNOTS.
SEAS CURRENTLY AVERAGE 2 FT NEARSHORE WITH 2.5 TO 3 FOOT SEAS
REPORTED FROM THE FRYING PAN SHOALS BUOY. SEAS SHOULD AVERAGE 2-3 FT
THROUGH TONIGHT IN A COMBINATION OF 4 SECOND WIND WAVE AND 9 SECOND
SOUTHEAST SWELL.
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 300 AM FRIDAY...A RELATIVELY WEAK FRONT OR SURFACE TROUGH WILL
REMAIN INLAND ALLOWING A PERSISTENT SOUTHWEST FLOW TO CONTINUE
THOUGH THE PERIOD. WIND SPEEDS WILL BE 10-15 KNOTS. IT APPEARS THERE
IS A LITTLE ENHANCEMENT OF THE LOW LEVEL WIND FIELDS OVERNIGHT
SATURDAY INTO SUNDAY MORNING WHICH WILL TILT THE SPEEDS TO THE
HIGHER END OF THE RANGE. SIGNIFICANT SEAS REMAIN UNCHANGED WITH 2-3
FEET SHORTER PERIOD WIND WAVES.
LONG TERM /MONDAY THROUGH TUESDAY/...
AS OF 300 AM FRIDAY...DIFFUSE FRONT DRAPED ACROSS THE AREA WILL NOT
HAVE A SIGNIFICANT IMPACT ON THE COASTAL WATERS FORECAST AT LEAST
FROM A SYNOPTIC STANDPOINT. SOUTHWEST WINDS OF AROUND TEN KNOTS WILL
PREVAIL WITH SIGNIFICANT SEAS OF 2-4 FEET. THE WAVEWATCH GUIDANCE IS
TRENDING UP FROM 2-3 FEET MONDAY TO 2-4 FEET TUESDAY MAINLY ACROSS
THE OUTER WATERS. PERIODS SHOW WIND WAVES WHICH GIVES ME PAUSE AS
THE WIND FIELDS REMAIN WEAK BUT THE INCREASE ISN/T A SIGNIFICANT
IMPACT ON THE FORECAST.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...SHK
NEAR TERM...TRA
SHORT TERM...SHK
LONG TERM...SHK
AVIATION...TRA
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1000 AM CDT FRI AUG 9 2013
.UPDATE...
ISSUED AT 1000 AM CDT FRI AUG 9 2013
CANADIAN RADARS CONTINUE TO SHOW SOME WEAK RETURNS DROPPING SOUTH
ASSOCIATED WITH A WEAK SHORTWAVE TROUGH ROTATING TOWARDS THE BASE
OF THE BROAD UPPER LOW OVER EASTERN CANADA. EXTENDED LOW POPS FOR
TODAY WESTWARD A BIT INTO THE NORTHERN VALLEY...BUT ANTICIPATE ANY
SHOWERS WILL REMAIN LIGHT AND RATHER ISOLATED. AFTERNOON TEMPS
WILL BE SIMILAR TO THE PAST FEW DAYS...ALTHOUGH NORTHWEST WINDS
WILL BE GUSTY AT TIMES.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 354 AM CDT FRI AUG 9 2013
PRIMARY CONCERNS TODAY ARE CLOUD COVER...TEMPERATURES...AND LOW
PRECIPITATION CHANCES. GFS/NAM/ECMWF/GEM ARE IN GOOD AGREEMENT AND
WILL USE A BLENDED SOLUTION FOR THIS FORECAST PACKAGE.
CLOSED 500 HPA LOW ACROSS CENTRAL ONTARIO WILL FINALLY BEGIN TO
PUSH EAST TODAY...ENTERING WESTERN QUEBEC BY 06 UTC TONIGHT.
ANOTHER SHORT-WAVE WILL SWING ACROSS THE FORECAST AREA WITH THE
PRIMARY IMPACT BEING A BAND OF STRATOCU AND LIGHT RAIN SHOWERS.
LATEST 925 TO 850 HPA RH FROM THE RAP SHOWS THESE CLOUDS MOVING AS
FAR SOUTH AS A LINE FROM LANGDON TO GRAND FORKS TO BEMIDJI BEFORE
BEGINNING TO DISSIPATE AND MOVE OUT THE REGION LATER THIS EVENING.
AS A RESULT...INCREASED SKY COVER ACROSS THE NORTHEASTERN THIRD OF
THE FORECAST AREA. ALSO ADDED ISOLATED SHOWER MENTION MAINLY
ACROSS ROSEAU/LAKE OF THE WOODS COUNTIES FROM 15 UTC TO 00 UTC
NOTING RECENT LIGHT RAIN REPORTS AT WINNIPEG AND AREAS UPSTREAM.
AREAS UNDER CLOUD COVER WILL STAY COOL TODAY WITH AFTERNOON HIGHS
MAINLY IN THE MID TO UPPER 60S...PERHAPS REACHING THE LOWER 70S
ALONG THE NORTHERN VALLEY FLOOR. AREAS SOUTH AND WEST WILL SEE
SOME AFTERNOON THERMAL CU GIVEN CONVECTIVE TEMPERATURES IN THE
UPPER 60S TO LOWER 70S...BUT SHOULD SEE ENOUGH SUN FOR HIGHS INTO
THE LOWER TO MID 70S.
SURFACE RIDGE WILL REMAIN ENTRENCHED ACROSS THE REGION OVERNIGHT...
RESULTING IN LIGHT WIND AND SOME DEGREE OF CLEARING ALTHOUGH DO
EXPECT SOME LINGERING CLOUD COVER FROM DEPARTING SHORT-WAVE.
OVERNIGHT LOWS WILL DROP INTO THE UPPER 40S TO NEAR 50 DEGREES.
MODELS HAVE SHIFTED A WARM AIR ADVECTION-INDUCED CONVECTIVE COMPLEX
FRIDAY NIGHT INTO SATURDAY AND SATURDAY NIGHT ALMOST ENTIRELY
SOUTH OF THE ND/SD BORDER. CUT POPS ACROSS ALL BUT THE FAR
SOUTHERN FORECAST AREA AND THIS MAY STILL BE TOO OPTIMISTIC. WILL
KEEP AREAS ACROSS THE NORTH DRY FOR NOW...BUT THERE IS ANOTHER
CANADIAN SHORT-WAVE THAT DROPS ACROSS THE REGION THAT COULD RESULT
IN SOME ISOLATED SHOWERS AWAY FROM THE MAIN CLUSTER ACROSS
SD/SOUTHERN MN. FILTERED SUNSHINE AND LIGHT WINDS SATURDAY WILL
ALLOW TEMPERATURES TO CLIMB INTO THE LOW TO MIDDLE 70S.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 354 AM CDT FRI AUG 9 2013
WITH THE EXCEPTION OF PERHAPS SOME LINGERING LIGHT SHOWERS ACROSS
THE FAR SOUTHEASTERN FORECAST AREA...SUNDAY WILL BE ANOTHER
TRANQUIL DAY WEATHER-WISE AS HIGH PRESSURE CONTINUES ACROSS THE
REGION. ABUNDANT SUNSHINE AND RISING MID-LEVEL THERMAL FIELDS WILL
RESULT IN TEMPERATURES IN THE MID TO UPPER 70S.
MONDAY TO THURSDAY...MODELS IN GOOD AGREEMENT WITH AN OVERALL DRY
PERIOD AS 500MB NW FLOW WITH SFC HIGH PRESSURE DOMINATES THE
WEATHER PATTERN ACROSS THE NORTHERN PLAINS FOR THE FIRST HALF OF
NEXT WEEK. EXPECTED DAYTIME HIGHS TO RISE A DEGREE OR TWO EACH DAY
WITH UPPER 70S ON MONDAY TO LOW 80S...NORMAL FOR MID AUGUST...BY
WEDNESDAY. THERE IS A CHC FOR SOME CONVECTIVE ACTIVITY IN THE AREA
ON WEDNESDAY NIGHT INTO THURSDAY AS A SHORTWAVE SYSTEM IS PROGGED
TO SLIDE OVER THE REGION.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 1000 AM CDT FRI AUG 9 2013
AREA OF MVFR CIGS PUSHING SOUTHWARD FROM MANITOBA SHUD OVERSPREAD
THE FAR NORTHERN FA DONW TO THE US HWY 2 CORRIDOR BY EARLY
AFTERNOON. EXPECT DATIME HEATING TO SLOLY LIFT THIS LOWER DECK SO
THAT BY MID AFTERNOON CIGS SHUD RECOVER ABV VFR THRESHOLD. SOUTH OF
HWY 2 CORRIDOR EXPECT MAINLY VFR CONDS WITH AN INCREASING VFR CLD
DECK IN THE AFTERNOON. NORTHERLY BLAYER WINDS GUSTING FROM 10 TO 20
MPH.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...MAKOWSKI
SHORT TERM...ROGERS
LONG TERM...ROGERS/JK
AVIATION...GUST
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
655 AM CDT FRI AUG 9 2013
.UPDATE...
ISSUED AT 655 AM CDT FRI AUG 9 2013
MADE SLIGHT ADJUSTMENTS TO HOURLY TEMPERATURES AND SKY COVER BASED
ON LATEST OBSERVATIONS. OTHERWISE...FORECAST IS ON TRACK WITH NO
MAJOR CHANGES AT THIS TIME.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 354 AM CDT FRI AUG 9 2013
PRIMARY CONCERNS TODAY ARE CLOUD COVER...TEMPERATURES...AND LOW
PRECIPITATION CHANCES. GFS/NAM/ECMWF/GEM ARE IN GOOD AGREEMENT AND
WILL USE A BLENDED SOLUTION FOR THIS FORECAST PACKAGE.
CLOSED 500 HPA LOW ACROSS CENTRAL ONTARIO WILL FINALLY BEGIN TO
PUSH EAST TODAY...ENTERING WESTERN QUEBEC BY 06 UTC TONIGHT.
ANOTHER SHORT-WAVE WILL SWING ACROSS THE FORECAST AREA WITH THE
PRIMARY IMPACT BEING A BAND OF STRATOCU AND LIGHT RAIN SHOWERS.
LATEST 925 TO 850 HPA RH FROM THE RAP SHOWS THESE CLOUDS MOVING AS
FAR SOUTH AS A LINE FROM LANGDON TO GRAND FORKS TO BEMIDJI BEFORE
BEGINNING TO DISSIPATE AND MOVE OUT THE REGION LATER THIS EVENING.
AS A RESULT...INCREASED SKY COVER ACROSS THE NORTHEASTERN THIRD OF
THE FORECAST AREA. ALSO ADDED ISOLATED SHOWER MENTION MAINLY
ACROSS ROSEAU/LAKE OF THE WOODS COUNTIES FROM 15 UTC TO 00 UTC
NOTING RECENT LIGHT RAIN REPORTS AT WINNIPEG AND AREAS UPSTREAM.
AREAS UNDER CLOUD COVER WILL STAY COOL TODAY WITH AFTERNOON HIGHS
MAINLY IN THE MID TO UPPER 60S...PERHAPS REACHING THE LOWER 70S
ALONG THE NORTHERN VALLEY FLOOR. AREAS SOUTH AND WEST WILL SEE
SOME AFTERNOON THERMAL CU GIVEN CONVECTIVE TEMPERATURES IN THE
UPPER 60S TO LOWER 70S...BUT SHOULD SEE ENOUGH SUN FOR HIGHS INTO
THE LOWER TO MID 70S.
SURFACE RIDGE WILL REMAIN ENTRENCHED ACROSS THE REGION OVERNIGHT...
RESULTING IN LIGHT WIND AND SOME DEGREE OF CLEARING ALTHOUGH DO
EXPECT SOME LINGERING CLOUD COVER FROM DEPARTING SHORT-WAVE.
OVERNIGHT LOWS WILL DROP INTO THE UPPER 40S TO NEAR 50 DEGREES.
MODELS HAVE SHIFTED A WARM AIR ADVECTION-INDUCED CONVECTIVE COMPLEX
FRIDAY NIGHT INTO SATURDAY AND SATURDAY NIGHT ALMOST ENTIRELY
SOUTH OF THE ND/SD BORDER. CUT POPS ACROSS ALL BUT THE FAR
SOUTHERN FORECAST AREA AND THIS MAY STILL BE TOO OPTIMISTIC. WILL
KEEP AREAS ACROSS THE NORTH DRY FOR NOW...BUT THERE IS ANOTHER
CANADIAN SHORT-WAVE THAT DROPS ACROSS THE REGION THAT COULD RESULT
IN SOME ISOLATED SHOWERS AWAY FROM THE MAIN CLUSTER ACROSS
SD/SOUTHERN MN. FILTERED SUNSHINE AND LIGHT WINDS SATURDAY WILL
ALLOW TEMPERATURES TO CLIMB INTO THE LOW TO MIDDLE 70S.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 354 AM CDT FRI AUG 9 2013
WITH THE EXCEPTION OF PERHAPS SOME LINGERING LIGHT SHOWERS ACROSS
THE FAR SOUTHEASTERN FORECAST AREA...SUNDAY WILL BE ANOTHER
TRANQUIL DAY WEATHER-WISE AS HIGH PRESSURE CONTINUES ACROSS THE
REGION. ABUNDANT SUNSHINE AND RISING MID-LEVEL THERMAL FIELDS WILL
RESULT IN TEMPERATURES IN THE MID TO UPPER 70S.
MONDAY TO THURSDAY...MODELS IN GOOD AGREEMENT WITH AN OVERALL DRY
PERIOD AS 500MB NW FLOW WITH SFC HIGH PRESSURE DOMINATES THE
WEATHER PATTERN ACROSS THE NORTHERN PLAINS FOR THE FIRST HALF OF
NEXT WEEK. EXPECTED DAYTIME HIGHS TO RISE A DEGREE OR TWO EACH DAY
WITH UPPER 70S ON MONDAY TO LOW 80S...NORMAL FOR MID AUGUST...BY
WEDNESDAY. THERE IS A CHC FOR SOME CONVECTIVE ACTIVITY IN THE AREA
ON WEDNESDAY NIGHT INTO THURSDAY AS A SHORTWAVE SYSTEM IS PROGGED
TO SLIDE OVER THE REGION.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 655 AM CDT FRI AUG 9 2013
VFR CONDITIONS WILL PERSIST AT ALL TAF SITES THROUGH 12 UTC
SATURDAY. CLEAR SKIES THIS MORNING WILL GIVE WAY TO SCT-BKN CU
LATE THIS MORNING AND AFTERNOON IN THE 4-5 KFT LAYER AGL...
ESPECIALLY ACROSS NORTHEAST ND INTO NORTHWEST MN. NORTHWEST
WINDS WILL INCREASE LATER THIS MORNING FROM 10 TO 15 KTS BEFORE
DECREASING AFTER SUNSET THIS EVENING.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...ROGERS
SHORT TERM...ROGERS
LONG TERM...ROGERS/JK
AVIATION...ROGERS
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
736 AM EDT FRI AUG 9 2013
.SYNOPSIS...
THE WARM MOIST AIR CONTINUES TO BRING SHOWERS TO THE REGION. A
COLD FRONT WILL BEGIN TO PUSH DRIER AIR INTO PENNSYLVANIA LATER
THIS AFTERNOON INTO EARLY SATURDAY. THE COLD FRONT WILL LIKELY
TRIGGER THUNDERSTORMS LATER TODAY. MUCH DRIER WILL MOVE OVER THE
ENTIRE REGION SATURDAY. A TROUGH BUILDS OVER NORTHEASTERN NORTH
AMERICA WHICH SHOULD KEEP US IN GENERALLY NORTHWEST FLOW MOST OF
THE NEXT 3-8 DAYS ENSURING WEAK FRONTAL PASSAGES AND GENERALLY LOW
HUMIDITY AND LOW PROBABILITY OF SIGNIFICANT RAINFALL.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
RADAR CONTINUES TO SHOW SHOWERS AND EMBEDDED THUNDERSTORMS MOVING
OVER THE MOISTURE BOUNDARY OVER CENTRAL PENNSYLVANIA BEST DEFINED
IN THE LOW-LEVEL THETA-E GRADIENT. THE LARGER SCALE THETA GRADIENT
IS IMPLYING THE FRONTAL PUSH TO OUR NORTHWEST IS NOT INTO
NORTHWESTERNMOST PA. SHOWERS WILL BECOME MORE NUMEROUS IN THE WEST
OVER THE NEXT FEW HOURS.
THE WARM MOIST AIR AND ABOVE NORMAL PW HAVE KEPT THE MORNING LOWS
MAINLY IN THE UPPER 60S AND 70S. GOING TO BE A WARM MOIST DAY OVER
CENTRAL AND SOUTHEASTERN AREAS.
THE PROBABILITY OF RAIN SHOULD DROP OFF FAST IN THE NW THIS
AFTERNOON. MOST FORECASTS FROM SREF TO HRRR IMPLY BY MID- LATE
AFTERNOON THE THREAT OF RAIN IN NW PASSES. EVEN CENTRAL AREAS
NOW APPEAR TO HAVE A GOOD SHOW OF NICE LATER AFTERNOON AND EARLY
EVENING AS THE DRIER AIR SLIDES TO THE SOUTHEAST.
SHOWERS AND STORMS WITH LOCALLY HEAVY RAIN FROM A FEW STRONGER
CELLS WILL LINGER LONGER IN THE SOUTHEAST.
TEMPS MAINLY 70S IN NEW TO MID-UPPER 80S SOUTHEAST. WINDS SHOULD
BECOME MORE WESTERLY IN NW PA THIS AFTERNOON.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
THE MODELS ALL SHOW LOWER PW AIR FILTERING INTO PA FAST. DROPPED
ALL POPS IN CENTRAL AND NORTHERN AREAS BEFORE 8 PM. LOWERED POPS
FAST IN THE SOUTHEAST WITH NO RAIN OF NOTE MUCH AFTER MIDNIGHT
THEN THE DRYING OUT BEGINS. ENSEMBLES IMPLY BY 0300 UTC ALL THREAT
OF RAIN IS TO OUR SOUTH AND EAST.
SATURDAY SHOULD BE MOSTLY SUNNY WITH TEMPERATURES NEAR NORMAL. THE
850 HPA TEMPS DO NOT DROP BELOW NORMAL UNTIL AFTER THIS PERIOD.
&&
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
THE COMING WEEK SHOULD BE RELATIVELY DRY AS MOST MODELS AT THIS
TIME AND ENSEMBLE FORECAST SYSTEMS (EFS) SHOW PW VALUES GENERALLY
NORMAL TO BELOW NORMAL. NOT A GOOD PATTERN FOR RAIN LET ALONE
HEAVY RAINFALL.
A MEAN TROUGH WILL DOMINATE THE EASTERN UNITED STATES WELL INTO
NEXT WEEK. SOME PIN WHEELING WAVES IMPLY CHANCES OF SCATTERED
SHOWERS SHOULD WE GET A ENOUGH MOISTURE OR INSTABILITY AHEAD OF
SOME OF THE WAVES. AT THIS TIME WE FLIRT WITH SOME MOISTURE TUES-WED
FOR SLIGHT INCREASE SHOWERS...NOT VERY IMPRESSIVE.
THE 850 HPA TEMPS ARE NORMAL TO SOME PERIODS WHERE THEY FALL
SLIGHTLY BELOW NORMAL. THE PW STAYS NORMAL TO BELOW NORMAL TOO.
THE PIN WHEELING TROUGHS OF COURSE PUSH THE WEAK SURGES OF COOLER
AND DRIER AIR IN.
THUS A GENERALLY COOL DRY WEEK IS CURRENTLY FORECAST.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
WIDE RANGE IN CONDITIONS THE LAST FEW HOURS.
MADE SOME ADJUSTMENTS TO THE 12Z TAFS.
SOME HEAVY SHOWERS DEVELOPING JUST EAST OF UNV NOW.
MORE WIDESPRED SHOWERS NOW TO THE WEST WITH THE FRONT.
EXPECT CONDITIONS TO IMPROVE FROM WEST TO EAST THIS AFT...
AS A WEAK COLD FRONT MOVES ACROSS THE AREA. DEWPOINTS ON
THE HIGH SIDE...BUT WINDS ALOFT NOT REAL STRONG FOR
SEVERE STORMS.
INTERESTING THING ABOUT DEWPOINTS. MAV GUIDANCE FCST A
DEWPOINT OF 75 IN MDT YESTERDAY. DEWPOINTS CAME UP HIGH...
BUT NOT THAT HIGH.
EXPECT SHOWERS AND STORMS TO TAPER OFF ACROSS THE FAR
SE ON SAT.
WEAK COLD ADVECTION TODAY INTO SAT...NOT A LOT OF COLD
ADVECTION BEFORE THE MIDDLE OF NEXT WEEK.
MAIN CONCERN WILL BE IF WE WILL GET FOG SAT AM...BEHIND
THE FRONT...AS TEMPS FALL TO NEAR THE CROSS OVER VALUE.
FOR NOW...HAVE FOG IN BFD.
LOOKS LIKE IT WILL BE MID WEEK...BEFORE ANY REAL DEEP
COLD AIR WORKS INTO CENTRAL PA.
OUTLOOK...
SAT...MVFR/IFR EARLY WITH PATCHY FOG...THEN VFR.
SUN-MON...GENERALLY VFR...BUT POSSIBLE AM RESTRICTIONS IN FOG.
TUE...VFR...BUT POSSIBLE RESTRICTIONS IN SHRA/TSRA WITH NEXT
COLD FRONT.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...GRUMM
NEAR TERM...GRUMM
SHORT TERM...GRUMM
LONG TERM...GRUMM/GARTNER
AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1113 AM EDT FRI AUG 9 2013
.SYNOPSIS...
MOIST SOUTHERLY FLOW WILL REMAIN ACROSS THE REGION THROUGH SATURDAY.
A COLD FRONT WILL MOVE SLOWLY SOUTH INTO THE AREA LATE THIS WEEKEND.
A SECOND COLD FRONT IS EXPECTED TO MOVE OVER THE REGION DURING THE
MID WEEK. DEEP MOISTURE MAY LINGER OVER THE SOUTHERN APPALACHIAN
REGION UNTIL NEXT WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1045 AM EDT...WILL DELAY THE ONSET OF ANY SCT TSTM COVERAGE
EAST OF THE MTNS UNTIL LATER IN THE AFTN GIVEN THE LACK OF
TRIGGERING AND LATEST HRRR MODEL CONVECTIVE TIMING. WILL PUSH UP THE
TIMING AND VALUE OF POPS IN THE WRN MTNS GIVEN MORE WESTERLY UPSLOPE
TRIGGERING AND LATEST HRRR AND RADAR TRENDS. MAX TEMPS HAVE ALSO
BEEN RAISED AT LEAST A DEGREE THROUGHOUT MOST OF THE AREA GIVEN THE
BETTER ISOLATION THAN YESTERDAY. FAR ERN PIEDMONT SECTIONS WILL SEE
HEAT INDEX VALUES CREEP POSSIBLY INTO THE UPPER 90S TODAY WITH NEAR
90 MAX TEMPS AND DEWPOINTS IN THE MID 70S...BUT THESE SHOULD REMAIN
WELL BELOW ADVISORY LEVELS.
OTHERWISE...DEEP SW FLOW WILL MAINTAIN UNSEASONABLY HIGH MOISTURE
LEVELS WITH PWAT VALUES IN THE NEIGHBORHOOD OF 2 INCHES OVER THE
AREA THROUGH THE PERIOD. WITH CLOUD BEARING WINDS ONLY AROUND 10
KTS...SLOW CELL MOVEMENT COMBINED WITH EFFICIENT RAINFALL PRODUCERS
WILL RESULT IN A LOCALIZED FLASH FLOOD THREAT...ESPECIALLY WITH ANY
CELLS THAT BECOME ANCHORED ON TERRAIN FEATURES OR OUTFLOW
BOUNDARIES.
MUCH LIKE LAST EVENING...MOST OF THE SHORT TERM AND MESOSCALE MODELS
FEATURE A RATHER ABRUPT CESSATION TO CONVECTIVE ACTIVITY THIS
EVENING...SO POPS WILL DIMINISH INTO THE OVERNIGHT HOURS...ALTHOUGH
THE APPROACH OF A FRONTAL BOUNDARY FROM THE TN VALLEY WILL
INCREASE THE CHANCES FOR CONVECTION TO WANDER INTO THE NC MTNS LATE
TONIGHT INTO EARLY SATURDAY...SO A CHANCE POP WILL BE CARRIED THERE
THROUGH THE OVERNIGHT.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 200 AM EDT FRIDAY...ON SATURDAY...BOTH THE GFS AND ECMWF
INDICATE THAT A WEST TO EAST BACK DOOR COLD FRONT WILL DRIFT SOUTH
ACROSS KY/VA. THE FORECAST AREA WILL REMAIN SOUTH OF THE
BOUNDARY...RESULTING IN LIGHT LLVL SOUTHWEST WINDS. GFS FORECAST
SOUNDINGS INDICATE THAT THE ENVIRONMENT ACROSS THE CWA WILL LIKELY
FEATURE PW VALUES IN EXCESS OF 2 INCHES...K INDEX VALUES IN THE
U30S...AND A DEEP LAYER OF RH VALUES GREATER THAN 80 PERCENT. IN
ADDITION...CAPE VALUES WILL LIKELY RANGE BETWEEN 1500-2000 J/KG
WITH WEAK LLVL CIN. MODELS INDICATE THAT A MID LEVEL RIDGE WILL
REMAIN CENTERED OFF THE GA COAST...RIDGING WEST INTO THE SOUTHERN
PLAINS. THE PATTERN WILL LIKELY FEATURE MODERATE H5 HEIGHTS OVER THE
UPPER SAVANNAH RIVER VALLEY...FAVORING THE NRN CWA FOR PASSAGES OF
POTENTIAL S/W. THE COMBINATION OF THE MOISTURE RICH
ENVIRONMENT...ADEQUATE CONDITIONAL INSTABILITY...AND THE PLACEMENT
OF THE SFC FRONT AND MID LEVEL S/W...I WILL CONTINUE TO INDICATE
LIKELY POPS ACROSS THE MTNS AND I-40 CORRIDOR...WITH SOLID CHC POPS
SOUTH.
GFS FORECAST SOUNDINGS INDICATE THAT THE MOIST ENVIRONMENT WILL
REMAIN THROUGH SUNDAY. SHORT RANGE MODELS INDICATE THAT THE SFC
FRONT WILL SLIP SLIGHTLY FURTHER SOUTH...POSSIBLY ENTERING THE I-40
CORRIDOR. THE MID LEVEL PATTERN WILL ONCE AGAIN FAVOR THE TRACK OF
ANY WEAK EMBEDDED S/W ACROSS THE NORTHERN HALF OF THE
CWA...ESPECIALLY DURING THE AFTERNOON. I WILL CONTINUE TO ADVERTISE
LIKELY POPS...BUT WILL INCREASE POPS ACROSS THE UPPER SAVANNAH RIVER
VALLEY FROM SATURDAY. THE MAIN THREAT OVER THE WEEKEND WILL BE THE
POTENTIAL FOR EXCESSIVE RAINFALL. HIGH TEMPERATURES WILL REMAIN
SLIGHTLY BELOW NORMAL THROUGH THE WEEKEND.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 220 AM EDT FRIDAY...THE EXTENDED PERIOD CONTINUES TO APPEAR
UNSETTLED. THE WEEKEND COLD FRONT MAY BECOME NEARLY STATIONARY OVER
THE CENTRAL CAROLINAS ON MONDAY...THEN PUSHING ACROSS THE LOW
COUNTRY ON TUESDAY. HOWEVER...CANADIAN HIGH PRESSURE WILL BUILD
ACROSS THE GREAT LAKES ON TUESDAY...POSSIBLY SWEEPING ANOTHER WEAK
BACK DOOR FRONT INTO THE FA TUESDAY NIGHT INTO WEDNESDAY. IT APPEARS
THAT WEDNESDAY AND WEDNESDAY NIGHT WILL BE FAVORABLE FOR SHRA/TSRA
DEVELOPMENT...GIVEN THE POSSIBLE PASSAGE OF A MID LEVEL TROF
COMBINED WITH FROPA/ISENTROPIC LIFT ACROSS THE SOUTHERN APPALACHIAN
REGION. I WILL INDICATE POPS BETWEEN 40 TO 50 PERCENT WEDNESDAY AND
WEDNESDAY NIGHT. DRIER AIR WILL BEGIN TO BUILD FROM THE NW DURING
THE DAY ON THURSDAY...BUT MOISTURE APPEARS TO REMAIN EAST OF THE
MTNS. I WILL INDICATE LOWERING POPS ON THURSDAY. OVERALL...THE
EXTENDED PERIOD APPEARS PRIMED FOR PERIODS OF HEAVY RAINFALL.
TEMPERATURES WILL VERY LIKELY VERIFY BELOW NORMAL THROUGH THE
PERIOD.
&&
.AVIATION /15Z FRIDAY THROUGH TUESDAY/...
AT KCLT AND ELSEWHERE...STILL ANTICIPATE FURTHER DEVELOPMENT OF
CUMULUS/STRATOCUMULS MVFR LEVEL SCT TO BKN CLOUDS WITH HEATING INTO
THE EARLY AFTN. SCATTERED CONVECTION IS ALSO EXPECTED TO DEVELOP
ACROSS MUCH OF THE AREA THIS AFTERNOON/EVENING. KAVL WILL BE THE
MOST LIKELY TERMINAL TO SEE CONVECTION...AS THE HIGH TERRAIN TO THE
SOUTHWEST APPEARS TO BE A FAVORED LOCATION FOR DEVELOPMENT THIS
AFTERNOON. CONVECTION IS EXPECTED TO GRADUALLY WANE TONIGHT...
ALTHOUGH CHANCES MAY INCREASE LATE TONIGHT ACROSS THE MOUNTAINS...AS
CONVECTION AHEAD OF A COLD FRONT INCHES ITS WAY ACROSS THE TN
VALLEY. WINDS WILL REMAIN OUT OF THE SW AT 7 TO 10 KTS. NOCTURNAL
FOG/STRATUS WILL BE POSSIBLE...BUT OCCURRENCE MAY DEPEND HEAVILY
UPON WHAT SITES RECEIVE RAINFALL LATER TODAY.
OUTLOOK...DEEP MOISTURE AND DAILY SHOWER/TSTM ACTIVITY WILL CONTINUE
THROUGH THE WEEKEND. IFR TO MVFR RESTRICTIONS WILL BE POSSIBLE LATE
EACH NIGHT/EARLY EACH MORNING...WITH ADDITIONAL RESTRICTIONS UNDER
ANY CONVECTION. CONDITIONS MAY STAY UNSETTLED THROUGH EARLY NEXT
WEEK.
CONFIDENCE TABLE...
15-21Z 21-03Z 03-09Z 09-15Z
KCLT HIGH 88% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 88% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 83% HIGH 98% HIGH 100% HIGH 100%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...NED
NEAR TERM...HG/JDL
SHORT TERM...NED
LONG TERM...NED
AVIATION...HG/JDL
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1051 AM CDT FRI AUG 9 2013
.UPDATE...
CONVECTION HAS BEEN PRETTY MUCH TIED TO FRONTAL BOUNDARY TO OUR
NORTHWEST BUT WE ARE ALSO BEGINNING TO SEE SCATTERED ACTIVITY
ALONG THE PLATEAU AND SOUTHEAST MIDDLE TENNESSEE. SHOULD SEE
SCATTERED SHOWERS AND STORMS DEVELOP IN THE MID STATE AS WE GO
THROUGH THE DAY AND THINGS HEAT UP. AM EXPECTING MORE NUMEROUS AND
STRONGER ACTIVITY TO OUR NORTH ACROSS SOUTHERN KENTUCKY DURING THE
AFTERNOON THAT WILL WORK ACROSS MY NORTHERN TIER OF COUNTIES IN
THE LATE AFTERNOON. A FEW OF THESE STORMS COULD BE STRONG TO
SEVERE WITH WET MICROBURTS.
FRONTAL BOUNDARY REMAINS DRAPED DOWN ALONG OHIO RIVER INTO EASTERN
OKLAHOMA WITH NOT MUCH IN THE WAY OF PUSH BEHIND IT. WE COULD BE
LOOKING AT ANOTHER ROUND OF LOCALIZED HEAVY RAIN IN HERE TONIGHT
AND SOME OF IT IN SAME AREA THAT GOT COPIOUS AMOUNTS NIGHT BEFORE
LAST. PRECIP EFFICENCY CLIMBS TO > 70 PERCENT NORTH HALF OF MID
STATE TONIGHT WITH MORE RAIN ON SATURDAY. WILL TAKE A CLOSER LOOK
AT THIS SHORTLY.
BOYD
&&
.PREV DISCUSSION... /ISSUED 634 AM CDT FRI AUG 9 2013/
UPDATE...FOR 12Z AVIATION DISCUSSION.
AVIATION...12Z AVIATION DISCUSSION.
UNCERTAINTIES...ACTUAL SFC FRONT TIMING MOVEMENT INTO NW PORTIONS OF
MID STATE/ASSOCIATED SHWR/TSTM CHANCES. SFC FRONT TO OUR NW WILL SLOWLY
MOVE INTO NW PORTIONS OF MID STATE BY 10/12Z. WITH MOISTURE RICH ATM IN
PLACE BUT WITH LITTLE INSTABILITY UNTIL 09/16Z-09/18Z...AND SLOW PROGGED
MOVEMENT OF FRONT...HARD TO PINPOINT EXACT SHWR/TSTM LOCATION DEVELOPMENT...
AND WILL MENTION ONLY VCTS REMARKS WITH VFR CEILINGS EXPECTED. AS FRONT
BEGINS TO MOVE INTO MID STATE AFTER 10/00Z...BELIEVE CAT SHWRS/TSTMS WILL
BECOME THE NORM...BUT CEILINGS SHOULD NOT GO BELOW VFR THRESHOLDS.
PREV DISCUSSION... /ISSUED 313 AM CDT FRI AUG 9 2013/
PATTERN THROUGH SUNDAY IS NOT CHANGING THAT MUCH. W-E RIDGE ALOFT
WILL REMAIN ANCHORED ACROSS THE DEEP SOUTH. FRONTAL BOUNDARY WILL
REMAIN TO THE NORTH OF TN. HOWEVER...THIS BOUNDARY WILL MAKE SOME
SOUTHWARD PROGRESS AND LATE FRI NIGHT INTO SATURDAY...SURFACE
CONVERGENCE WILL COUPLE WITH DIVERGENCE ALOFT TO PROVIDE AN
INCREASING CHANCE OF CONVECTION. MOISTURE PARAMETERS PICK UP ON IT
AS WELL WITH THE DEEPEST MOISTURE...BETWEEN NOW AND
SUNDAY...OCCURRING LATE FRI NT AND INTO SATURDAY.
FOR TODAY...LATEST HRRR SHOWING A LULL IN ANY CONVECTION UNTIL
AROUND 19Z OR SO. THE ACTIVITY ACROSS SOUTHERN KY SHOULD LIFT ON OFF
TO THE ENE...BUT WESTERN AND NW AREAS MAY SEE SOME CONVECTION
MOVE IN FROM THE WEST LATER THIS MORNING. HRRR EXPECTS THE
CONVECTION TO WEAKEN THOUGH. OTW...CAP EROSION IS STILL APPARENT
THIS AFTERNOON WITH CAPES ON THE INCREASE. THUS...LOOK FOR SCT
ACTIVITY THIS AFTERNOON. AGAIN...POP CHANCES TO INCREASE LATE
TONIGHT AND ON SATURDAY.
ON SUNDAY...BOUNDARY SHOWS A DECREASE IN FORCING BUT PROXIMITY
INFLUENCES ARE GREATER WITH THE STATIONARY BOUNDARY RIGHT OVER US.
THUS...APPRECIABLE 40-50 POPS WILL CONTINUE.
FOR THE NEAR TERM TEMPS...KEEPING IN MIND THAT THE MAV GUIDANCE HAS
PERFORMED RATHER MISERABLY ON HIGH TEMPS RECENTLY...WILL AGREE TO
BELIEVE IN A CONTINUATION OF THAT FORTUITOUS TREND. WILL UNDERCUT
EACH DAY BY 3 DEG OR SO. WILL GO NEAR TO SLIGHTLY BELOW ON MINS.
IN THE EXT FCST...UPPER TROUGHING PATTERN OVER THE EASTERN U.S. WILL
BEGIN TO EVOLVE. PVA UPSTREAM WILL CATCH UP WITH WEAK SFC BOUNDARIES
AND INTENSIFY A W-E COLD FRONT ALONG THE OHIO RIVER BY MID WEEK.
THIS FEATURE WILL DROP SLOWLY SOUTHWARD WITH A FROPA OCCURRING WED
OR THU. IN ADVANCE OF THE FROPA..CONVECTION CHANCES WILL CONTINUE
WITH THE GREATEST PROBABILITIES OCCURRING TUES AND WED. BEYOND THE
SCOPE OF THE 7 DAY EXT...PERHAPS A DRIER AND SLIGHTLY COOLER AIRMASS
WILL SETTLE IN. 18Z FRI TEMPS FROM A VARIETY OF MODELS ALL SUGGEST A
COOLER TREND...A PRE FALL TASTE OF DRIER PERHAPS? WE WILL SEE.
VERSUS THE EXT TEMPS...850 MB TEMPS AND A SFC 18Z AND 12Z REVIEW ALL
SUGGESTS THAT THE MEX NUMBERS FOR HIGH TEMPS ARE TOO HIGH. WILL
UNDERCUT BY A FEW DEGREES THROUGHOUT THE PERIOD. MINS LOOK GENERALLY
OK.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
01
AREA FORECAST DISCUSSION...UPDATED
NWS NASHVILLE TN
634 AM CDT FRI AUG 9 2013
.UPDATE...FOR 12Z AVIATION DISCUSSION.
&&
.AVIATION...12Z AVIATION DISCUSSION.
UNCERTAINTIES...ACTUAL SFC FRONT TIMING MOVEMENT INTO NW PORTIONS OF
MID STATE/ASSOCIATED SHWR/TSTM CHANCES. SFC FRONT TO OUR NW WILL SLOWLY
MOVE INTO NW PORTIONS OF MID STATE BY 10/12Z. WITH MOISTURE RICH ATM IN
PLACE BUT WITH LITTLE INSTABILITY UNTIL 09/16Z-09/18Z...AND SLOW PROGGED
MOVEMENT OF FRONT...HARD TO PINPOINT EXACT SHWR/TSTM LOCATION DEVELOPMENT...
AND WILL MENTION ONLY VCTS REMARKS WITH VFR CEILINGS EXPECTED. AS FRONT
BEGINS TO MOVE INTO MID STATE AFTER 10/00Z...BELIEVE CAT SHWRS/TSTMS WILL
BECOME THE NORM...BUT CEILINGS SHOULD NOT GO BELOW VFR THRESHOLDS.
&&
.PREV DISCUSSION... /ISSUED 313 AM CDT FRI AUG 9 2013/
PATTERN THROUGH SUNDAY IS NOT CHANGING THAT MUCH. W-E RIDGE ALOFT
WILL REMAIN ANCHORED ACROSS THE DEEP SOUTH. FRONTAL BOUNDARY WILL
REMAIN TO THE NORTH OF TN. HOWEVER...THIS BOUNDARY WILL MAKE SOME
SOUTHWARD PROGRESS AND LATE FRI NIGHT INTO SATURDAY...SURFACE
CONVERGENCE WILL COUPLE WITH DIVERGENCE ALOFT TO PROVIDE AN
INCREASING CHANCE OF CONVECTION. MOISTURE PARAMETERS PICK UP ON IT
AS WELL WITH THE DEEPEST MOISTURE...BETWEEN NOW AND
SUNDAY...OCCURRING LATE FRI NT AND INTO SATURDAY.
FOR TODAY...LATEST HRRR SHOWING A LULL IN ANY CONVECTION UNTIL
AROUND 19Z OR SO. THE ACTIVITY ACROSS SOUTHERN KY SHOULD LIFT ON OFF
TO THE ENE...BUT WESTERN AND NW AREAS MAY SEE SOME CONVECTION
MOVE IN FROM THE WEST LATER THIS MORNING. HRRR EXPECTS THE
CONVECTION TO WEAKEN THOUGH. OTW...CAP EROSION IS STILL APPARENT
THIS AFTERNOON WITH CAPES ON THE INCREASE. THUS...LOOK FOR SCT
ACTIVITY THIS AFTERNOON. AGAIN...POP CHANCES TO INCREASE LATE
TONIGHT AND ON SATURDAY.
ON SUNDAY...BOUNDARY SHOWS A DECREASE IN FORCING BUT PROXIMITY
INFLUENCES ARE GREATER WITH THE STATIONARY BOUNDARY RIGHT OVER US.
THUS...APPRECIABLE 40-50 POPS WILL CONTINUE.
FOR THE NEAR TERM TEMPS...KEEPING IN MIND THAT THE MAV GUIDANCE HAS
PERFORMED RATHER MISERABLY ON HIGH TEMPS RECENTLY...WILL AGREE TO
BELIEVE IN A CONTINUATION OF THAT FORTUITOUS TREND. WILL UNDERCUT
EACH DAY BY 3 DEG OR SO. WILL GO NEAR TO SLIGHTLY BELOW ON MINS.
IN THE EXT FCST...UPPER TROUGHING PATTERN OVER THE EASTERN U.S. WILL
BEGIN TO EVOLVE. PVA UPSTREAM WILL CATCH UP WITH WEAK SFC BOUNDARIES
AND INTENSIFY A W-E COLD FRONT ALONG THE OHIO RIVER BY MID WEEK.
THIS FEATURE WILL DROP SLOWLY SOUTHWARD WITH A FROPA OCCURRING WED
OR THU. IN ADVANCE OF THE FROPA..CONVECTION CHANCES WILL CONTINUE
WITH THE GREATEST PROBABILITIES OCCURRING TUES AND WED. BEYOND THE
SCOPE OF THE 7 DAY EXT...PERHAPS A DRIER AND SLIGHTLY COOLER AIRMASS
WILL SETTLE IN. 18Z FRI TEMPS FROM A VARIETY OF MODELS ALL SUGGEST A
COOLER TREND...A PRE FALL TASTE OF DRIER PERHAPS? WE WILL SEE.
VERSUS THE EXT TEMPS...850 MB TEMPS AND A SFC 18Z AND 12Z REVIEW ALL
SUGGESTS THAT THE MEX NUMBERS FOR HIGH TEMPS ARE TOO HIGH. WILL
UNDERCUT BY A FEW DEGREES THROUGHOUT THE PERIOD. MINS LOOK GENERALLY
OK.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
31
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1035 AM CDT FRI AUG 9 2013
.UPDATE...
NE-SW BAND OF MORNING CONVECTION HAS BUT ABOUT ALL DIED AWAY
OUTSIDE OF A FEW SPRINKLES FROM COMANCHE TO STEPHENVILLE. VISIBLE
SATELLITE INDICATES A SHARP CONTRAST FROM CLOUDY SKIES UNDERNEATH
THIS ONE-TWO COUNTYWIDE BAND...TO MOSTLY SUNNY SKIES. MEANWHILE A
WEAK SURFACE LOW/BOUNDARY WAS ORIENTED FROM NEAR GRAHAM TO BETWEEN
BOWIE AND WICHITA FALLS.
THE WEAK SURFACE BOUNDARY IS EXPECTED TO SLOWLY MOVE SOUTHEAST
ACROSS THE NORTHWEST COUNTIES PER THE RUC/SREF FORECASTS. BEST
PWATS BETWEEN 1.75-2.00 INCHES WILL ALSO BE IN THE VICINITY ON THE
NORTHWEST EDGE OF THE UPPER RIDGE ANCHORED OVER THE WESTERN GULF
COAST. AS A SHORTWAVE DISTURBANCE OVER SE COLORADO DROPS SE OVER
CENTRAL/WESTERN OKLAHOMA...ENOUGH DIFFERRENTIAL HEATING/LIFT OFF THE
NORTHWEST EDGE OF MORNING CLOUDS WILL COINCIDE WITH RICH MOISTURE
AND INSTABILITY FOR ISOLATED TO SCATTERED STORMS MAINLY NORTH OF
I-20 AND WEST OF I-35W LATER THIS AFTERNOON AND EVENING.
FREQUENT LIGHTNING AND GUSTY DOWNBURST WINDS WOULD BE THE MAIN
THREATS WITH ANY STRONG TO BRIEF SEVERE STORMS THROUGH SUNSET.
ISOLATED ACTIVITY MAY MAINTAIN AFTER DARK IN THIS AREA WITH THE
SHORTWAVE NEARBY...BUT OVERALL CONVECTIVE COVERAGE SHOULD GRADUALLY
DIMINISH WITH LOSS OF STRONG DAYTIME HEATING.
WHERE THE WEAK SURFACE BOUNDARY ENDS UP SATURDAY IS ANYONE/S GUESS
AND HAVE LEFT CURRENT POPS INTACT.
05/
&&
.AVIATION...
FOR THE 12Z TAFS...EARLY MORNING SHOWERS AND THUNDERSTORMS AROUND
THE DFW AREA IS THE PRIMARY AVIATION WEATHER CONCERN TODAY.
ALTHOUGH RAIN SHOWERS AND THUNDERSTORMS TO THE WEST AND SOUTHWEST
OF THE DFW AREA HAVE BEEN SLOW TO BUILD OVER THE METROPLEX...THIS
ACTIVITY IS STILL EXPECTED TO MOVE/DEVELOP NORTHEAST THIS MORNING.
THE HRRR REMAINS PERSISTENT IN INDICATING SCATTERED SHOWERS OVER
THE DFW METROPLEX THIS MORNING AND IR SATELLITE INDICATES COOLING
CLOUD TOPS SPREADING OVER TARRANT AND DALLAS COUNTIES. COOLING
CLOUD TOPS ARE EVIDENCE OF SOME MID-LEVEL ASCENT ORIENTED
SOUTHEAST OF A QUASI-STATIONARY FRONT LOCATED NORTHWEST OF THE DFW
METROPLEX.
WITH FORCING FOR ASCENT INDICATED BY SATELLITE IMAGERY...CONFIDENCE
IN THE HRRR FORECAST IS SUFFICIENTLY HIGH TO INCLUDE A MENTION OF
VCTS IN METROPLEX AREA TAFS THIS MORNING THROUGH 16Z. EXPECT RAIN
SHOWERS WITH ISOLATED STORMS TO DEVELOP OVER TARRANT COUNTY AFTER
12Z...SPREADING EAST INTO DALLAS COUNTY THROUGH 14Z.
AFTERNOON AND SURFACE BASED THUNDERSTORM ACTIVITY IS EXPECTED TO
REMAIN CLOSELY TIED TO THE STATIONARY FRONT...AND THEREFORE SHOULD
REMAIN NORTHWEST OF THE DFW METROPLEX. OTHERWISE...VFR CONDITIONS
ARE EXPECTED THROUGH THE FORECAST PERIOD.
CAVANAUGH
&&
.PREV DISCUSSION... /ISSUED 346 AM CDT FRI AUG 9 2013/
ISOLATED SHOWERS EXPECTED THIS MORNING IN A BAND OF ENHANCED
MOISTURE EXTENDING FROM EASTLAND TO GAINESVILLE. THIS ACTIVITY
WILL DISSIPATE BY MID TO LATE MORNING...WITH DIMINISHING CLOUD
COVER LEADING TO HIGH TEMPERATURES ONCE AGAIN AT OR ABOVE 100 IN
MOST AREAS. LIKE YESTERDAY...A FEW AREAS THAT EXPERIENCE SHOWERS
AND MORE PERSISTENT MORNING CLOUD COVER MAY REMAIN IN THE UPPER
90S FOR HIGHS. SURFACE DEWPOINTS ARE EXPECTED TO MIX OUT INTO THE
50S AND LOWER 60S IN MOST AREAS AGAIN THIS AFTERNOON...WHICH
SHOULD HELP KEEP HEAT INDEX VALUES BELOW 105. HOWEVER...A FEW
VALUES NEAR OR JUST ABOVE 105 CAN BE EXPECTED THIS AFTERNOON...AND
AGAIN SATURDAY AFTERNOON...BEFORE THE DRIER AIR MIXES DOWN TO THE
NEAR SURFACE LAYER.
FOR THIS AFTERNOON...EXPECT WIDELY SCATTERED THUNDERSTORM
DEVELOPMENT TO FOCUS ALONG A WEAK SURFACE TROUGH/STATIONARY FRONT
THAT CURRENTLY EXTENDS JUST SOUTH OF THE RED RIVER. ADDITIONAL
OUTFLOW BOUNDARIES EXIST ACROSS NORTH TEXAS...BUT SUBSIDENCE FROM
UPPER HIGH IS STRONGER FURTHER SOUTH. WILL FORECAST 20 POPS IN AN
AREA NORTHWEST OF DFW NEAR THE EXPECTED LOCATION OF THE FRONTAL
BOUNDARY NEAR MAX HEATING TIME. IF SURFACE DEWPOINTS CAN REMAIN IN
THE MID 60S NEAR THE BOUNDARY...LOCAL SURFACE BASED CAPE VALUES
AROUND 2000 J/KG CAN BE EXPECTED. ANY STORM THAT DOES DEVELOP OR
SPREAD INTO NORTH TEXAS NEAR OR JUST AFTER MAX HEATING WILL BE
CAPABLE OF DAMAGING DOWNBURST WINDS.
EXPECT ANY REMAINING CONVECTION TO DISSIPATE BY MIDNIGHT
TONIGHT...WITH PARTLY CLOUDY SKIES EXPECTED. FOR SATURDAY AND
SUNDAY AFTERNOON AND EVENING...EXPECT THE BEST CHANCES FOR
CONVECTION TO BE NEAR THE SURFACE BOUNDARY WHICH IS FORECAST TO
EXTEND ACROSS THE EASTERN AND SOUTHERN PARTS OF THE CWA. THE
OPERATIONAL NAM SUGGESTS THE POTENTIAL FOR A GREATER COVERAGE OF
CONVECTION JUST SOUTH AND SOUTHEAST OF THE METROPLEX SATURDAY
AFTERNOON AND EVENING. HOWEVER...THAT SOLUTION IS NOT SUPPORTED BY
THE OTHER AVAILABLE GUIDANCE AND WILL THEREFORE KEEP POPS NO
HIGHER THAN 20 PERCENT. PROXIMITY OF UPPER RIDGE AND OVERALL
SHALLOW ASCENT NEAR THE BOUNDARY SUGGEST THAT THE NAM IS LIKELY
TOO WET FOR THE SATURDAY AFTN/EVE PERIOD.
DRY WEATHER EXPECTED ON MONDAY AND TUESDAY AS THE RIDGE THAT WILL
BE ALIGNED WEST-EAST ACROSS THE SOUTHERN U.S. OVER THE WEEKEND
REDEVELOPS IN A NORTH-SOUTH FASHION ALONG THE ROCKY MOUNTAINS.
WITH TROUGHING FORECAST IN THE NORTHEAST U.S...THE RESULTING
NORTHWEST FLOW PATTERN WILL BE FAVORABLE FOR A MORE SUBSTANTIAL...
ALBEIT STILL RELATIVELY WEAK...COLD FRONT TO MOVE INTO NORTH
TEXAS. WITH MOISTURE STILL IN PLACE AND UPPER RIDGE WELL OFF TO THE
WEST...EXPECT ONE OR MORE ROUNDS OF SCATTERED CONVECTION TO AFFECT
PARTS OF NORTH AND CENTRAL TEXAS. WILL SPREAD POPS FROM NORTH TO
SOUTH ACROSS THE AREA STARTING TUESDAY NIGHT AND CONTINUING
THROUGH DAY 7 /THURSDAY AUG 15/. ITS TOO EARLY TO GO HIGHER THAN
ABOUT 30 POPS...BUT LATER FORECASTS MAY RAISE THE WEDS-THURS POPS
IF PATTERN CHANGE CONTINUES TO EVOLVE AS EXPECTED. ADDITIONAL
CLOUD COVER AND AREAS OF RAIN WILL HOLD TEMPERATURES DOWN INTO THE
LOWER AND MID 90S ON THURSDAY.
09/PATRICK
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 102 78 101 80 98 / 20 10 10 10 10
WACO, TX 100 77 100 77 98 / 5 5 20 20 10
PARIS, TX 100 75 97 74 96 / 20 20 10 10 20
DENTON, TX 102 75 99 78 98 / 20 20 10 10 10
MCKINNEY, TX 102 76 101 78 98 / 20 10 10 10 20
DALLAS, TX 103 81 103 81 99 / 20 10 10 10 10
TERRELL, TX 103 77 102 78 98 / 10 10 20 20 20
CORSICANA, TX 103 77 101 79 98 / 5 5 20 20 20
TEMPLE, TX 100 74 99 75 97 / 5 5 20 20 20
MINERAL WELLS, TX 101 74 100 76 98 / 20 10 10 10 10
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
69/05
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
653 AM CDT FRI AUG 9 2013
.AVIATION...
FOR THE 12Z TAFS...EARLY MORNING SHOWERS AND THUNDERSTORMS AROUND
THE DFW AREA IS THE PRIMARY AVIATION WEATHER CONCERN TODAY.
ALTHOUGH RAIN SHOWERS AND THUNDERSTORMS TO THE WEST AND SOUTHWEST
OF THE DFW AREA HAVE BEEN SLOW TO BUILD OVER THE METROPLEX...THIS
ACTIVITY IS STILL EXPECTED TO MOVE/DEVELOP NORTHEAST THIS MORNING.
THE HRRR REMAINS PERSISTENT IN INDICATING SCATTERED SHOWERS OVER
THE DFW METROPLEX THIS MORNING AND IR SATELLITE INDICATES COOLING
CLOUD TOPS SPREADING OVER TARRANT AND DALLAS COUNTIES. COOLING
CLOUD TOPS ARE EVIDENCE OF SOME MID-LEVEL ASCENT ORIENTED
SOUTHEAST OF A QUASI-STATIONARY FRONT LOCATED NORTHWEST OF THE DFW
METROPLEX.
WITH FORCING FOR ASCENT INDICATED BY SATELLITE IMAGERY...CONFIDENCE
IN THE HRRR FORECAST IS SUFFICIENTLY HIGH TO INCLUDE A MENTION OF
VCTS IN METROPLEX AREA TAFS THIS MORNING THROUGH 16Z. EXPECT RAIN
SHOWERS WITH ISOLATED STORMS TO DEVELOP OVER TARRANT COUNTY AFTER
12Z...SPREADING EAST INTO DALLAS COUNTY THROUGH 14Z.
AFTERNOON AND SURFACE BASED THUNDERSTORM ACTIVITY IS EXPECTED TO
REMAIN CLOSELY TIED TO THE STATIONARY FRONT...AND THEREFORE SHOULD
REMAIN NORTHWEST OF THE DFW METROPLEX. OTHERWISE...VFR CONDITIONS
ARE EXPECTED THROUGH THE FORECAST PERIOD.
CAVANAUGH
&&
.PREV DISCUSSION... /ISSUED 346 AM CDT FRI AUG 9 2013/
ISOLATED SHOWERS EXPECTED THIS MORNING IN A BAND OF ENHANCED
MOISTURE EXTENDING FROM EASTLAND TO GAINESVILLE. THIS ACTIVITY
WILL DISSIPATE BY MID TO LATE MORNING...WITH DIMINISHING CLOUD
COVER LEADING TO HIGH TEMPERATURES ONCE AGAIN AT OR ABOVE 100 IN
MOST AREAS. LIKE YESTERDAY...A FEW AREAS THAT EXPERIENCE SHOWERS
AND MORE PERSISTENT MORNING CLOUD COVER MAY REMAIN IN THE UPPER
90S FOR HIGHS. SURFACE DEWPOINTS ARE EXPECTED TO MIX OUT INTO THE
50S AND LOWER 60S IN MOST AREAS AGAIN THIS AFTERNOON...WHICH
SHOULD HELP KEEP HEAT INDEX VALUES BELOW 105. HOWEVER...A FEW
VALUES NEAR OR JUST ABOVE 105 CAN BE EXPECTED THIS AFTERNOON...AND
AGAIN SATURDAY AFTERNOON...BEFORE THE DRIER AIR MIXES DOWN TO THE
NEAR SURFACE LAYER.
FOR THIS AFTERNOON...EXPECT WIDELY SCATTERED THUNDERSTORM
DEVELOPMENT TO FOCUS ALONG A WEAK SURFACE TROUGH/STATIONARY FRONT
THAT CURRENTLY EXTENDS JUST SOUTH OF THE RED RIVER. ADDITIONAL
OUTFLOW BOUNDARIES EXIST ACROSS NORTH TEXAS...BUT SUBSIDENCE FROM
UPPER HIGH IS STRONGER FURTHER SOUTH. WILL FORECAST 20 POPS IN AN
AREA NORTHWEST OF DFW NEAR THE EXPECTED LOCATION OF THE FRONTAL
BOUNDARY NEAR MAX HEATING TIME. IF SURFACE DEWPOINTS CAN REMAIN IN
THE MID 60S NEAR THE BOUNDARY...LOCAL SURFACE BASED CAPE VALUES
AROUND 2000 J/KG CAN BE EXPECTED. ANY STORM THAT DOES DEVELOP OR
SPREAD INTO NORTH TEXAS NEAR OR JUST AFTER MAX HEATING WILL BE
CAPABLE OF DAMAGING DOWNBURST WINDS.
EXPECT ANY REMAINING CONVECTION TO DISSIPATE BY MIDNIGHT
TONIGHT...WITH PARTLY CLOUDY SKIES EXPECTED. FOR SATURDAY AND
SUNDAY AFTERNOON AND EVENING...EXPECT THE BEST CHANCES FOR
CONVECTION TO BE NEAR THE SURFACE BOUNDARY WHICH IS FORECAST TO
EXTEND ACROSS THE EASTERN AND SOUTHERN PARTS OF THE CWA. THE
OPERATIONAL NAM SUGGESTS THE POTENTIAL FOR A GREATER COVERAGE OF
CONVECTION JUST SOUTH AND SOUTHEAST OF THE METROPLEX SATURDAY
AFTERNOON AND EVENING. HOWEVER...THAT SOLUTION IS NOT SUPPORTED BY
THE OTHER AVAILABLE GUIDANCE AND WILL THEREFORE KEEP POPS NO
HIGHER THAN 20 PERCENT. PROXIMITY OF UPPER RIDGE AND OVERALL
SHALLOW ASCENT NEAR THE BOUNDARY SUGGEST THAT THE NAM IS LIKELY
TOO WET FOR THE SATURDAY AFTN/EVE PERIOD.
DRY WEATHER EXPECTED ON MONDAY AND TUESDAY AS THE RIDGE THAT WILL
BE ALIGNED WEST-EAST ACROSS THE SOUTHERN U.S. OVER THE WEEKEND
REDEVELOPS IN A NORTH-SOUTH FASHION ALONG THE ROCKY MOUNTAINS.
WITH TROUGHING FORECAST IN THE NORTHEAST U.S...THE RESULTING
NORTHWEST FLOW PATTERN WILL BE FAVORABLE FOR A MORE SUBSTANTIAL...
ALBEIT STILL RELATIVELY WEAK...COLD FRONT TO MOVE INTO NORTH
TEXAS. WITH MOISTURE STILL IN PLACE AND UPPER RIDGE WELL OFF TO THE
WEST...EXPECT ONE OR MORE ROUNDS OF SCATTERED CONVECTION TO AFFECT
PARTS OF NORTH AND CENTRAL TEXAS. WILL SPREAD POPS FROM NORTH TO
SOUTH ACROSS THE AREA STARTING TUESDAY NIGHT AND CONTINUING
THROUGH DAY 7 /THURSDAY AUG 15/. ITS TOO EARLY TO GO HIGHER THAN
ABOUT 30 POPS...BUT LATER FORECASTS MAY RAISE THE WEDS-THURS POPS
IF PATTERN CHANGE CONTINUES TO EVOLVE AS EXPECTED. ADDITIONAL
CLOUD COVER AND AREAS OF RAIN WILL HOLD TEMPERATURES DOWN INTO THE
LOWER AND MID 90S ON THURSDAY.
09/PATRICK
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 102 78 101 80 98 / 20 10 10 10 10
WACO, TX 100 77 100 77 98 / 5 5 20 20 10
PARIS, TX 100 75 97 74 96 / 10 10 10 10 20
DENTON, TX 102 75 99 78 98 / 20 20 10 10 10
MCKINNEY, TX 102 76 101 78 98 / 20 10 10 10 20
DALLAS, TX 103 81 103 81 99 / 10 10 10 10 10
TERRELL, TX 103 77 102 78 98 / 5 10 20 20 20
CORSICANA, TX 103 77 101 79 98 / 5 5 20 20 20
TEMPLE, TX 100 74 99 75 97 / 5 5 20 20 20
MINERAL WELLS, TX 101 74 100 76 98 / 30 20 10 10 10
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
/
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1017 AM EDT FRI AUG 9 2013
.SYNOPSIS...
A SLOW MOVING COLD FRONT IS EXPECTED TO APPROACH THE REGION FROM
THE NORTHWEST THIS AFTERNOON BEFORE PASSING SOUTHEAST THROUGH OUR
AREA THIS WEEKEND. HIGH PRESSURE OVER THE UPPER MIDWEST SHIFTS
SOUTHEAST THROUGH THE MID ATLANTIC BY THE END OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 935 AM EDT FRIDAY...
FOG/STRATUS FADING WITH BETTER HEATING UNDER LESS CLOUD COVER
THIS MORNING AND EXPECT MOST TO CLEAR IN THE NEXT HOUR OR SO. OTRW
FRONT REMAINS STALLED OUT ACROSS THE SRN OHIO VALLEY THIS MORNING
PRECEDED BY A BAND OF SHRA/TSRA ASSOCIATED WITH WEAK S/W ENERGY
ALONG THE RESIDUAL PRE-FRONTAL ZONE. MORNING SOUNDINGS SHOW BETTER
FLOW ALOFT AHEAD OF THE FRONT/WAVE THIS MORNING WITH DECENT
WESTERLY FLOW WHICH SHOULD HELP SHRA/TSRA MOVE A BIT FASTER THIS
AFTERNOON. HOWEVER UNIDIRECTIONAL TRAJECTORY MAY OFFSET THIS BY
ALLOWING STORMS TO ALIGN IN BANDS ESPCLY AS THE SFC-85H STEERING
BRIEFLY TURNS MORE SW WITH THE PASSING VORT NOW OVER KY AROUND MID
AFTERNOON. THIS SHOULD HELP PROMPT DEVELOPMENT ALONG THE SRN BLUE
RIDGE AS SEEN VIA SEVERAL SOLNS WITH ANOTHER AREA ACROSS THE FAR
NW WITH THE SAGGING CONVECTION TO THE NW. LATEST MODIFIED RAOBS
ALSO SHOW MUCH MORE CAPE/INSTABILITY PER MORE INSOLATION THIS
AFTERNOON ESPCLY BLUE RIDGE EAST WHERE STRONGER STORMS APPEAR
LIKELY PER BETTER JET ALOFT. STILL APPEARS THREAT FOR FLOODING
RAINFALL WILL BE MORE LOCALIZED UNLESS BLUE RIDGE CONVECTION AND
COVERAGE TO THE NW COMES TOGETHER SO STILL HOLDING OFF ON ANY
WATCHES FOR NOW.
OTRW HAVE ADJUSTED POPS FOR SLOWER ARRIVAL NW GIVEN CURRENT RADAR
TRENDS AND INCREASED TO LIKELYS IN A BAND BLUE RIDGE VICINITY
WHERE 2-3K J/KG CAPES POSSIBLE. WEST WIND ALONG WITH COMPRESSION
AHEAD OF THE FRONT SHOULD COMBO WITH HEATING AND +19-20C AT 85H TO
PUSH HIGHS TO ARND 90 SE AND MAINLY 80S ELSW PER OBSERVED
THICKNESS.
PREVIOUS DISCUSSION AS OF 330 AM EDT FRIDAY...
RADARS QUIET THIS MORNING WITH ONLY ONE LONE SHOWER EXITING NRN
GREENBRIER COUNTY WITH MOST CONVECTION CENTERED WITH AND AHEAD OF A
SHORTWAVE AROUND CINCINNATI. THE 12Z ECMWF/00Z GFS ZERO IN ON THIS
SHORTWAVE AND PRECIP AND MAINLY SEE IT SHIFTING ENE INTO NRN WV
LATER THIS MORNING WITH A FEW SHOWERS MAKING ITS WAY INTO SE WV. FOR
EARLY TODAY WILL BE DEALING WITH AREAS OF FOG...LOCALLY DENSE AS IT
HAS CLEARED OUT SOME ASIDE FROM SOME HIGH CLOUDS. THIS FOG WILL BE
GOING AWAY AROUND 900 AM.
LOOKING AT WSW FLOW BACKING DURING THE DAY AND AFTER MIDDAY MODELS
SHOWING SOME LOW LVL CONVERGENCE ALONG THE BLUE RIDGE WITH A
PREFRONTAL TROUGH...WITH UPPER SUPPORT AND MAIN FRONT STAYING ACROSS
THE OHIO VALLEY INTO THE MID ATLANTIC. THINK COVERAGE WILL AGAIN
BECOME SCATTERED TO NUMEROUS OVER THE MOUNTAINS THEN SHIFT TO THE
PIEDMONT AS FLOW BACKS. WITH BETTER MIXING AND MORE SUNSHINE...THE
INSTABILITY AND CONVECTIVE TEMPS SUPPORT MORE THUNDER. STORMS WILL
BE HEAVY RAIN PRODUCERS AND MEAN FLOW SHOWING STORM MOVEMENT OF 10
TO 20 MPH. OVERALL THREAT FOR SVR THUNDERSTORMS AND FLASH FLOODING
REMAINS ISOLATED...SO NO WATCHES FOR FLASH FLOODING EXPECTED AND
WILL CONTINUE TO MENTION HEAVY RAIN...ISOLATED SVR IN THE HWO.
AS WE HEAD INTO LATE AFTERNOON AND EARLY EVENING THE LOW LVL FLOW
VEERS TO THE WEST AND THE GFS ESPECIALLY DRIES THE LEE SIDE OF THE
MOUNTAINS OUT WHILE HOLDING ONTO CONVECTION IN THE PIEDMONT...SO
WILL BE LEANING TOWARD LOWER POPS IN THE NEW RIVER VALLEY/FOOTHILLS
BY DUSK WHILE KEEPING THE WRN SLOPES AND PIEDMONT WITH HIGHER POPS.
OUR LOCAL WRF AND HRRR SHOWING THIS TO BE THE CASE AS WELL.
THINK WILL SEE SHOWERS AND STORMS SUBSIDE AGAIN BY LATE
EVENING/MIDNIGHT ESPECIALLY IN THE EAST WITH LOSS OF HEATING BUT
EXPECT THE THREAT OF SHOWERS TO REMAIN OVER THE WV/FAR SW VA MTNS
AHEAD OF THE FRONT AND CLOSER TO THE UPPER LEVEL SUPPORT.
FOR HIGHS TODAY WENT CLOSE TO THE ECMWF MOS AS THE GFS SEEMS TO WARM
AND NAM TOO COOL. LOOKING AT WARMER TEMPS WITH MORE SUN AND MIXING
BEFORE STORMS SET IN...WITH LOWER 80S WEST TO MID 80S TO NEAR 90
EAST.
TONIGHT REMAINS MUGGY WITH LOWS GENERALLY IN THE MID TO UPPER 60S
MOUNTAINS INTO THE LOWER 70S EAST.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY NIGHT/...
AS OF 400 AM EDT FRIDAY...
SHOWERS AND THUNDERSTORMS WILL REMAIN IN THE FORECAST THIS WEEKEND
INTO THE NEXT WORKWEEK AS A COLD FRONT MAKES ITS WAY ACROSS OUR
REGION. IN STICKING CLOSE WITH THE ECMWF MODEL SOLUTION...EXPECT TO
START SATURDAY OFF WITH THE COLD FRONT SITUATED NEAR THE INTERSTATE
81 CORRIDOR...WITH THE FRONT DRIFTING SLOWLY SOUTHWARD THROUGH THE
DAY...PERHAPS AIDED IN ITS PUSH BY OUTFLOW FROM AFTERNOON/EVENING
SHOWERS AND THUNDERSTORMS. BY SUNDAY MORNING...THE FRONT IS EXPECTED
TO ADVANCE INTO NORTH CAROLINA...WHERE IT WILL STALL AND BEGIN TO
WASH OUT ON MONDAY AS ANOTHER COLD FRONT APPROACHES FROM THE UPPER
MIDWEST.
DESPITE THE PASSAGE OF THE FRONT...WILL STILL SEE ABUNDANT LOW LEVEL
MOISTURE ACROSS OUR AREA AS DRIER AIR LINGERS TO OUR NORTH. MINOR
DISTURBANCES ALOFT WILL CONTINUALLY PASS ALONG THE FRONT FROM THE
WEST DURING THE WEEKEND...AND WILL TRIGGER ROUNDS OF SHOWERS AND
THUNDERSTORMS...MAINLY EACH AFTERNOON AND EVENING WHEN ENHANCED BY
DAYTIME HEATING. AS IN PREVIOUS NIGHTS...BELIEVE WE WILL SEE A
DRASTIC REDUCTION IN THE AMOUNT OF SHOWER ACTIVITY AFTER
SUNSET...ALTHOUGH CANNOT RULE A FEW SHOWERS DURING THE OVERNIGHTS.
WILL ALSO POINT OUT THE POSSIBILITY OF A FEW STRONG STORMS ON
SATURDAY AND SUNDAY...MORE SO SOUTH OF INTERSTATE 81. WHILE STRONG
THUNDERSTORM WINDS AND FREQUENT LIGHTNING WILL BE CONCERNS...THE
GREATEST CONCERN WILL BE FROM LOCALLY HEAVY RAIN AND THE POSSIBILITY
OF FLASH FLOODING. ANY FLOODING SHOULD REMAIN LOCAL IN SCALE...BUT
MAY DEVELOP QUICKLY IN STORMS WITH HIGH RAINFALL RATES...AND
ESPECIALLY IN LOCATIONS WITH SATURATED SOILS FROM RECENT HEAVY RAIN.
&&
.LONG TERM /TUESDAY THROUGH THURSDAY/...
AS OF 350 PM EDT THURSDAY...
A COLD FRONT ASSOCIATED WITH AN IMPRESSIVE CHUNK OF CHILLY AIR FOR
THIS TIME OF YEAR WILL ALLOW SHOWERS AND STORMS TO CROP UP AGAIN ON
TUESDAY. ONCE THIS BOUNDARY PASSES...H85 TEMPS MAY FALL AS COLD AS
+9C BY THE MIDDLE OF NEXT WEEK. THE CHILLY AIR ALOFT WILL PRODUCE
EXTENSIVE CLOUDS AND PROBABLY WIDELY SCATTERED SHOWERS. BY THE END
OF NEXT WEEK...THIS FRONT BEGINS TO JOG NORTH AGAIN AND WARMER AIR
RETURNS.
&&
.AVIATION /13Z FRIDAY THROUGH TUESDAY/...
AS OF 740 AM EDT FRIDAY...
FOG/LOW CLOUDS SHOULD CLEAR OUT THIS MORNING BY 14Z. SHOWERS AND
SOME STORMS MOVE TOWARD BLF/LWB AFTER 15Z AND MORESO IN THE
AFTERNOON. MODELS SHOWING MORE DEVELOPMENT IN THE EAST SO WILL
HAVE PREDOMINANT SHOWERS AT ALL SITES. SOME DIFFERENCES IN THE
ENDING TIME BUT THINK THE BCB/ROA AREA WILL CLEAR OUT SOONER WHILE
WINDS TURN TO THE WEST...WHILE DAN/LYH/BLF/LWB MAY SEE SHOWERS
LINGER INTO THE EVENING. KEPT VCTS IN THERE FOR NOW BUT CONFIDENCE
HIGH FOR MORE THUNDER TODAY GIVEN MORE SUN.
APPEARS FOG AND LOWER STRATUS COULD BE AN ISSUE AGAIN LATE FRIDAY
NIGHT.
THE FRONT SHIFTS SLOWLY SOUTHEAST THRU THE WEEKEND AND KEEPS THE
THREAT OF SHOWERS/STORMS AROUND. THE FRONT MAY SLIP SOUTH OF THE
AREA BY MONDAY INTO TUESDAY WITH STILL SOME THREAT OF SHOWERS OVER
THE SRN CWA FROM DAN-BCB-BLF.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...WP
NEAR TERM...JH/WP
SHORT TERM...NF
LONG TERM...KM
AVIATION...WP
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
348 PM EDT FRI AUG 9 2013
.SYNOPSIS...
A COLD FRONT WILL CONTINUE TO SLOWLY MOVE EAST ACROSS THE REGION
THROUGH TONIGHT. THIS FRONT WILL THEN STALL TO OUR SOUTH THROUGH
MONDAY, WITH A FEW WAVES OF LOW PRESSURE POSSIBLY MOVING ALONG THE
BOUNDARY. ANOTHER COLD FRONT FROM THE WEST WILL TRACK ACROSS THE
REGION DURING TUESDAY, FOLLOWED BY HIGH PRESSURE BUILDING IN FROM
THE GREAT LAKES FOR THE REMAINDER OF THE WORK WEEK.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
THE GFS INITIALIZATION LOOKED SLIGHTLY BETTER THAN THE WRF-NMMB AT
MOST LEVELS, ALTHOUGH IT WAS NOT BY MUCH. OVERALL THE OVERNIGHT SPC
HRW WRF-ARW CONTINUES TO LOOK CLOSEST OF THE SOUNDING RUN MESOSCALE
MODELS (HAVE TO BUMP IT UP AN HR OR TWO IN TIMING). IN THE NEARER
TERM REMOVING THE DC CLUSTER THAT IS NOT THERE, THE HRRR SERIES HAS
BEEN A FAIR COMPROMISE BETWEEN THE RAP AND COSPA.
LOOKING AT ALL OF THE MESOSCALE MODELS AND SYNOPTIC SCALE MODELS,
THE GENERAL CONSENSUS IS THAT CONVECTION SHOULD BE PEAKING WITHIN
OUR CWA BETWEEN 20Z AND 22Z. THIS COINCIDES WITH WEAK PVA AND THE
PASSING OF THE LOW LEVEL THETA E RIDGE. THEY HAVE ALSO BEEN PRETTY
CONSISTENT ON THIS ACTIVITY BECOMING THE MAIN THRUST IN OUR CWA
WITH CONVECTION TO OUR WEST WEAKENING. THE AXIS OF MAX MLCAPE IS
OVER OUR CWA SO THIS DOES SEEM LOGICAL IF WE DO RAIN OUT THE
APPROACHING CONVECTION. ITS NOT GOING TO HAVE AS CONDUCIVE
INSTABILITY ONCE THAT BATCH ARRIVES. MAYBE THE CIRRUS BLOW OFF, THE
WEAK LAPSE RATES AND OR THE LACK OF MID LEVEL QVEC CONVERGENCE, WE
HAVE NOT SEEN A LINE FORM AND IF ONE WERE IT LOOKS TO BE PRETTY FAR
EAST IN OUR CWA.
SO FOR THE NEAR NEAR TERM WE FOLLOWED THIS PREMISE WITH HIEST POPS
THRU 22Z. HOWEVER DONT WANT TO DROP THE FLASH FLOOD WATCH UNTIL WE
SEE THIS CONVECTION WEAKEN. THE 10 PM EXPIRATION TIME AS FAR AS THE
HEAVY RAIN PART OF THE WATCH APPEARS IT WILL BE TOO LATE.
SEVERE/STRONG CHANCES LOOK TO REMAIN ISOLATED. WHILE BULK SHEAR
VALUES ARE ADEQUATE IT LOOKS AS THOUGH THE CONVECTION GOING FROM
HIGHER TO LESSER SHEARED VALUES ARE NOT HAVING MUCH SUCCESS. AGAIN
THIS COULD BE RELATED ALSO TO THE WEAK MID LEVEL LAPSE RATES,
UPDRAFTS MAY NOT BE STRONG ENOUGH IN A SHEARED ENVIRONMENT AND NOT
MUCH DRY AIR AROUND (DCAPES ARE NEAR ZERO!!!)
THE FRONT ITSELF IS STILL FAIRLY FAR WEST IN PA AND GETTING IT TO
REACH THE DELAWARE VALLEY MUCH BEFORE 03Z IS UNLIKELY. SO WHILE WE
CARRY THE HIEST POPS EARLY, WE DID CONTINUE SOME CHANCE THROUGH MOST
OF THE EVENING IN OUR CWA.
DEBRIS CLOUDINESS EXPECTED FOR A CHUNK OF THE NIGHT, ESPECIALLY
SOUTHERN HALF. COUPLED WITH SOME WEAK NW WINDS POST FRONTAL, WE DID
NOT DIFFER MUCH FROM STAT GUIDANCE. GIVEN THAT DEW POINTS ARE
SUPPOSE TO DROP OVERNIGHT, DID NOT PUT IN ANY FOG IN THE GRIDS.
CHANCES ARE IF WE ARE WRONG THIS IS MORE OF AN AVIATION CONCERN THAN
PUBLIC.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/...
A DRY SATURDAY IS FORECAST FOR OUR CWA WITH LOWER HUMIDITY LEVELS.
THE COLD FRONT IS EXPECTED TO CLEAR ALL OF OUR CWA BY 12Z AND THE
FCST INSTABILITY DOES NOT SUPPORT THUNDER, DOESNT SUPPORT SHOWERS
EITHER. MIGHT HAVE A HARD TIME EVEN SUPPORTING MUCH IN THE WAY OF
CUMULUS.
WITH THE JET STREAM PASSING OVERHEAD SOME CIRRUS SHOULD BE AROUND.
THE SHORT WAVE THE GFS IS PASSING ACROSS OUR CWA LOOKS TOO SUSTAINED
BASED ON THE LACK OF THE CONVECTION ASSOCIATED WITH IT DURING THE
PRECEDING 6 TO 12 HOURS. MAX TEMPS LEANED GFS MOS`S WAY BASED ON
FCST 925MB AND 850MB TEMPS AS WELL AS LLVL THICKNESSES. BUT IN SPITE
OF SIMILAR MAX TEMPS TO TODAY, TOMORROW WILL FEEL MUCH BETTER WITH
THE LOWER DEW POINTS.
&&
.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
THROUGH THE FIRST PART OF THE LONG TERM, A STALLED FRONTAL BOUNDARY
WILL BE PRESENT OFF TO OUR SOUTH, EXTENDING ACROSS PORTIONS OF
VIRGINIA AND PERHAPS INTO THE CAROLINAS. A DRIER STRETCH OF WEATHER
IS EXPECTED FOR MUCH OF THE FORECAST AREA FROM SATURDAY NIGHT
THROUGH MONDAY, AS THE FRONTAL BOUNDARY IS PROGGED TO REMAIN OFF TO
OUR SOUTH WITH WEAK HIGH PRESSURE TO THE WEST INFLUENCING OUR
REGION. A FEW SHORTWAVES/VORT MAXES ARE FORECAST TO PASS THROUGH THE
MID-LEVEL FLOW DURING THIS TIMEFRAME, SO SOME ISOLATED SHWRS/TSTORMS
CANNOT BE COMPLETELY RULED OUT. OUR SOUTHERN ZONES WOULD BE THE MOST
PROBABLE AREA FOR THIS ACTIVITY, WITH THE STALLED FRONT OFF TO THE
SOUTH. FOR NOW, WE WILL KEEP LOW POPS IN PLACE, WITH THE BEST
POTENTIAL FOR ISOLATED TO SCATTERED SHWRS/TSTORMS BEING ON MONDAY AS
THE MODELS SHOW A WAVE OF LOW PRESSURE DEVELOPING ALONG THE STALLED
BOUNDARY.
FOR TUESDAY, BOTH THE GFS AND ECMWF SHOW POSSIBLE LOW PRESSURE AND
ANOTHER COLD FRONT APPROACHING FROM THE WEST AND TRACKING THROUGH
OUR AREA. WHILE THERE ARE SOME TIMING DIFFERENCES BETWEEN THE MODELS
WITH THE EASTWARD PROGRESSION OF THE FRONT ON TUESDAY, THIS DOES
LOOK TO BE THE BEST OPPORTUNITY FOR MORE WIDESPREAD SCATTERED
CONVECTIVE ACTIVITY ACROSS THE FORECAST AREA, AND HIGH CHANCE POPS
ARE IN PLACE. THEREAFTER, A QUIETER STRETCH OF WEATHER IS EXPECTED
FOR THE REST OF THE WORK WEEK AS THE COLD FRONT PROGRESSES EAST AND
OFFSHORE EARLY WEDNESDAY, WITH HIGH PRESSURE FROM AROUND THE GREAT
LAKES REGION BUILDING TOWARD THE MID ATLANTIC. DAYTIME TEMPERATURES
IN THE WEDNESDAY THROUGH FRIDAY TIMEFRAME ARE EXPECTED TO BE A
LITTLE BELOW AVERAGE FOR MID-AUGUST, WITH HIGHS RANGING FROM THE
MIDDLE 70S TO THE LOWER 80S.
&&
.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
18Z TAFS WILL CARRY THUNDERSTORMS ALL TERMINALS, BUT THEN
GENERALLY BETTER FLYING CONDITIONS ARE EXPECTED FROM THIS EVENING
ONWARD.
WE HAVE TEMPORARY MVFR CONDITIONS DURING THUNDERSTORMS FOR THE REST
OF THIS AFTERNOON AND VFR CONDITIONS BETWEEN. THERE COULD BE ONE OR
TWO BANDS OF THUNDER. SOUTHWEST WINDS WILL AVERAGE 10 TO 15 KNOTS
WITH SOME GUSTS TO AROUND 20 KNOTS. STRONGER GUSTS IN THUNDER ARE
POSSIBLE AT THE SOUTHEASTERN TERMINALS AND AIRPORTS.
FOR LATE THIS AFTERNOON AND EARLY EVENING, SOME SHOWERS MIGHT
LINGER, BUT BELIEVE THE IMPACT SHOULD BE MINIMAL WITH GENERALLY
VFR CONDITIONS. WINDS SHOULD VEER SLIGHTLY MORE TO THE WEST AND
WE DID DROP THE GUSTINESS.
OVERNIGHT, WE EXPECT THE CFP WITH VFR DEBRIS MID AND HIGH LEVEL
CLOUDS. WINDS WILL BECOME NORTHWEST AT 5 TO 10 KNOTS. WITH DRIER
AIR MOVING IN, GUIDANCE AND OUR TAFS ARE NOT CARRYING FOG.
SOMETIMES GUIDANCE GETS TOO BULLISH WITH THE MIXING ON SUMMER
NIGHTS AND WE WILL REVISIT. THE LEAST CONFIDENCE ABOUT LACK OF FOG
IS AT RURAL AND MORE OUTLYING TERMINALS.
THEN ON SATURDAY MORNING, NOT MUCH CHANGE IN SKY CONDITIONS OR
WINDS EXPECTED. SO THE LAST FORECAST PERIOD IN THE CURRENT TAF
SHOULD HOLD FOR THE TERMINALS THROUGH THE MORNING.
A SEA BREEZE FRONT MIGHT FORM SATURDAY AFTERNOON FOR NOW EXPECTED
BEYOND THE END OF THE CURRENT TAF CYCLE AND NOT REACHING KPHL BY 00Z.
OUTLOOK...
SATURDAY NIGHT THROUGH MONDAY...MAINLY VFR CONDITIONS. ISOLATED
SHWRS/TSTORMS REMAIN POSSIBLE, ESPECIALLY MONDAY.
TUESDAY...VFR TO POSSIBLE MVFR AT TIMES WITH SCATTERED SHWRS/TSTORMS
POSSIBLE. LIGHT SOUTHERLY WINDS EARLY BECOME WEST-NORTHWEST LATER
TUESDAY EVE/NIGHT.
WEDNESDAY...VFR CONDITIONS EXPECTED WITH LIGHT WINDS.
&&
.MARINE...
WE WILL CONTINUE THE SCA NORTHERN WATERS INTO THIS EVENING. THE
ENTRANCE TO NEW YORK HARBOR BUOY`S SEAS HAVE RISEN TO AROUND 4 FEET
AND WITH THE CONTINUED SOUTHERLY FLOW INTO EARLY THIS EVENING, WE
MIGHT MEET THE SEAS CRITERIA. MEANWHILE THE DELAWARE BAY BUOY`S SEAS
CONTINUE TO VERIFY BELOW WAVE WATCH GUIDANCE AND THEIR WINDOW OF
OPPORTUNITY FOR SMALL CRAFT ADVISORY CONDITIONS IS CLOSING FAST.
ONCE THE FRONT CLEARS, THE WESTERLY FLOW BEHIND IT IS NOT THAT
STRONG AND SUB SMALL CRAFT ADVISORY CONDITIONS ARE EXPECTED THROUGH
SATURDAY. A SEA BREEZE FRONT SHOULD FORM ON SATURDAY AFTERNOON.
OUTLOOK...
FROM SATURDAY NIGHT THROUGH MONDAY, A FRONTAL BOUNDARY WILL REMAIN
STALLED TO THE SOUTH OF OUR FORECAST AREA AND ADJACENT COASTAL
WATERS. WINDS AND SEAS THROUGH THIS TIMEFRAME ARE EXPECTED TO BE AT
SUB-SCA LEVELS, WITH SEAS IN THE 2 TO 3 FOOT RANGE AND WINDS AT
15 KNOTS OR LESS. A COLD FRONT IS FORECAST TO CROSS THE AREA
TUESDAY, BRINGING A BETTER CHANCE FOR SCATTERED SHWRS/TSTORMS,
FOLLOWED BY HIGH PRESSURE BUILDING ACROSS THE REGION AND COASTAL
WATERS DURING WEDNESDAY. CONDITIONS ON OUR AREA WATERS ARE EXPECTED
TO REMAIN AT SUB-ADVISORY LEVELS THROUGH TUESDAY AND WEDNESDAY.
&&
.HYDROLOGY...
FLASH FLOOD WATCH CONTINUES FOR NORTHERN COUNTIES. UP TO 4 INCHES OF
RAIN HAS FALLEN OVERNIGHT LEAVING THIS AREA MORE SUSCEPTIBLE TO
FLOODING TODAY. ELSEWHERE WHILE THERE IS A LOWER CHANCE, ITS NOT A
ZERO CHANCE, BUT THE MESOSCALE MODELS CONTINUE TO SHOW FAIRLY
PROGRESSIVE STORMS, SO UNLESS THERE IS TRAINING, THE RISK STILL
APPEARS LOWER THAN LOCATIONS THAT HAVE BEEN ALREADY DOUSED THE PAST
24 HOURS.
&&
.RIP CURRENTS...
A MODERATE RISK FOR THE FORMATION OF RIP CURRENTS CONTINUES
THROUGH THIS EVENING ALONG THE NEW JERSEY COAST.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...FLASH FLOOD WATCH UNTIL 10 PM EDT THIS EVENING FOR PAZ054-055-
061-062.
NJ...FLASH FLOOD WATCH UNTIL 10 PM EDT THIS EVENING FOR NJZ001-
007>010.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR ANZ450-
451.
&&
$$
SYNOPSIS...KLINE
NEAR TERM...GIGI
SHORT TERM...GIGI
LONG TERM...KLINE
AVIATION...GIGI/KLINE
MARINE...GIGI/KLINE
HYDROLOGY...GIGI
RIP CURRENTS...
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
110 PM EDT FRI AUG 9 2013
.SYNOPSIS...
A COLD FRONT WILL SLOWLY APPROACH FROM THE WEST THIS AFTERNOON AND
MOVE THROUGH THE REGION BY EARLY SATURDAY. THIS FRONT WILL THEN
STALL TO OUR SOUTH THROUGH MONDAY. A FEW WAVES OF LOW PRESSURE MAY
MOVE ALONG THIS BOUNDARY FOR THE EARLY PART OF THE WEEK. ANOTHER
COLD FRONT WILL CROSS THE REGION FROM THE WEST AROUND TUESDAY,
FOLLOWED BY AN AREA OF HIGH PRESSURE FOR WEDNESDAY AND THURSDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SPC HRW WRF-ARW IS VERIFYING THE BEST OF THE MESOSCALE MODELS THIS
MORNING AND WAS USED AS A BACK END TIMING OF HIGHER POPS. ON THE
FRONT SIDE, THE HRRR GETS VIGOROUS RATHER QUICKLY WHICH GIVEN WE
ARE NEARING THE CONVECTIVE TEMP CAN NOT BE DISCOUNTED. THE
OPERATIVE WORD FROM HERE ON OUT IS THAT ALL OF THE MESOSCALE MODEL
PROGRESSIONS EVEN IF NOT GEOGRAPHICALLY CORRECT ARE OF DECENT
MOVEMENT. THIS WOULD REDUCE THE FLASH FLOOD THREAT IN PLACES THAT
WERE NOT DOUSED THIS MORNING. OTHERWISE, NO BIG CHANGES TO THE
CONVECTIVE CONCERNS. THE MID LEVEL LAPSE RATES ARE NOT IMPRESSIVE
AND WARMER AIR CONTINUES TO MOVE IN AT 700MB AND 500MB. THERE MAY
BE A WINDOW SERN CWA BECAUSE OF THE CAPPING WHERE THE INITIAL
RELEASE MIGHT PRODUCE VIGOROUS ENOUGH UPDRAFTS TO CAUSE
THUNDERSTORMS TO POSSIBLY REACH SEVERE LIMITS. LESS LIKELY NORTH
AND WEST OF I95 WHERE CONVECTION SHOULD BE RAMPING UPWARD PRETTY
QUICKLY.
BASED ON CURRENT TEMPS AND SUNSHINE, WE NUDGED MAX TEMPS UP
SLIGHTLY AGAIN SERN PART OF OUR CWA.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SATURDAY/...
THE FRONT WILL CONTINUE CROSSING THE AREA TONIGHT. POPS DECREASE
FROM NORTH TO SOUTH AND THE NIGHT PROGRESSES. WINDS SHIFT TO WRLY
THEN NWRLY OVERNIGHT AND DRIER AIR BEGINS TO ARRIVE OVER THE AREA.
IT MAY TAKE UNTIL AFTER DAWN SAT TO BEGIN MIXING THE DRIER AIR DOWN.
OVERNIGHT LOW TEMPS TONIGHT WILL RANGE FROM THE LOW 60S ACROSS THE
NORTH TO THE LOW 70S OVER THE SOUTH...WHERE THE FRONT WILL CROSS
LATE.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
AT THE START OF THE EXTENDD PD, THE AFOREMENTIONED CDFNT WILL BE
OFF THE CST AND ALL OF THE MDL GUID IS IN REASONABLE AGREEMENT
THAT SAT SHOULD BE MOSTLY IF NOT ALL DRY. IF THERE IS TO BE ANY
LINGERING PRECIP, IT WILL BE EARLY AND ACRS THE S. FOR NOW, WILL
JUST KEEP SOME VERY LOW POPS ACRS SRN AREAS EARLY AND THIS COULD
END UP BEING OVERDONE.
HIGH PRESSURE THEN BUILD IN BEHIND THE FRONT, WHICH WILL REMAIN
STALLED S OF THE REGION AND SUNDAY LOOKS PREDOMINANTLY DRY AS
WELL. SOME OF THE GUID IS INDICATING SOME POPS OVER THE EXTREME
SRN AREAS, WHILE OTHER GUID KEEPS THE POPS S OF THE CWA. SINCE THE
GFS (THE GUID WITH THE MOST NWD EXTENT) OFTEN OVERDOES ITS PRECIP
FIELD, AM INCLINED TO GO WITH THE OTHER SOLNS ATTM, BUT MAY NEED
TO INCREASE POPS LATER ON SUN ACRS THE S IF OTHER GUID COMES INTO
AGREEMENT.
BY MON, BOTH THE ECMWF AND GFS WANT TO BRING A WEAK LOW TO THE S
AND AGAIN ITS A QUESTION OF HOW FAR N ANY PRECIP WOULD COME. ONCE
AGAIN, THE GFS HAS A FURTHER N EXTENT, BUT BOTH MDLS INDICATE A
STRONGER LOW, SO HAVE BOUGHT OFF ON A MORE NRN EXTENT THIS TIME
AND BROUGHT SOME LOW POPS EVERYWHERE, BUT THIS IS LOW CONFIDENCE.
BY TUE, A CDFNT WILL BE APPROACHING FROM THE W AND WILL CROSS THE
REGION BY TUE NIGHT. THIS LOOKS TO BE OUR BEST CHC OF RAIN.
BEHIND THE CFP, HIGH PRESSURE WILL BUILD DOWN FROM THE NRN PLAINS
AND BRING DRY WX FOR WED AND THU.
TEMPS LOOK TO BE AT OR SLIGHTLY ABOVE NRML THRU MIDWEEK AND THEN
WILL BE A TAD BELOW NRML BEHIND THE TUE FROPA AS THE HIGH BUILDS
IN, DEW POINTS WILL BE QUITE PLEASANT FOR MID AUGUST THOUGH.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
18Z TAFS WILL CARRY THUNDERSTORMS ALL TERMINALS, BUT THEN
GENERALLY BETTER FLYING CONDITIONS ARE EXPECTED FROM THIS EVENING
ONWARD.
EXCEPT FOR KACY AND KMIV (WHICH START AT 19Z), WE WILL START THE
TAFS WITH TEMPORARY MVFR CONDITIONS DURING THUNDERSTORMS AND VFR
CONDITIONS BETWEEN. THERE COULD BE ONE OR TWO BANDS OF THUNDER.
SOUTHWEST WINDS WILL AVERAGE 10 TO 15 KNOTS WITH SOME GUSTS TO
AROUND 20 KNOTS. STRONGER GUSTS IN THUNDER ARE POSSIBLE AT THE
SOUTHEASTERN TERMINALS AND AIRPORTS.
FOR LATE THIS AFTERNOON AND EARLY EVENING, SOME SHOWERS MIGHT
LINGER, BUT BELIEVE THE IMPACT SHOULD BE MINIMAL WITH GENERALLY
VFR CONDITIONS. WINDS SHOULD VEER SLIGHTLY MORE TO THE WEST AND
WE DID DROP THE GUSTINESS.
OVERNIGHT, WE EXPECT THE CFP WITH VFR DEBRIS MID AND HIGH LEVEL
CLOUDS. WINDS WILL BECOME NORTHWEST AT 5 TO 10 KNOTS. WITH DRIER
AIR MOVING IN, GUIDANCE AND OUR TAFS ARE NOT CARRYING FOG.
SOMETIMES GUIDANCE GETS TOO BULLISH WITH THE MIXING ON SUMMER
NIGHTS AND WE WILL REVISIT. THE LEAST CONFIDENCE ABOUT LACK OF FOG
IS AT RURAL AND MORE OUTLYING TERMINALS.
THEN ON SATURDAY MORNING, NOT MUCH CHANGE IN SKY CONDITIONS OR
WINDS EXPECTED. SO THE LAST FORECAST PERIOD IN THE CURRENT TAF
SHOULD HOLD FOR THE TERMINALS THROUGH THE MORNING.
OUTLOOK...
SAT NGT THROUGH MON...THERE COULD BE SOME LINGERING LOWER CIGS
EARLY SAT, ESPECIALLY ACRS THE S, OTHERWISE...MAINLY VFR
CONDITIONS EXPECTED. ISOLATED SHWRS/TSTMS REMAIN POSSIBLE,
ESPECIALLY MONDAY. HIGH CONFIDENCE.
TUES...VFR TO POSSIBLE MVFR AT TIMES WITH SCATTERED SHWRS/TSTMS
POSSIBLE AS CDFNT CROSSES THE REGION FROM W TO E. WNDSHFT WITH
CFP. MDT TO HIGH CONFIDENCE.
&&
.MARINE...
WINDS AND SEAS WILL SLOWLY BUILD TODAY AS THE LOW PRESSURE SYSTEM TO
THE NORTH AND ITS ATTACHED FRONT BEGIN TO MOVE TOWARD THE AREA. IT
APPEARS THAT THERE WILL BE A WEAK INVERSION IN PLACE TODAY...BUT
PROBABLY ENOUGH MIXING TO ALLOW SOME OF THE LOW LEVEL WINDS (AROUND
30 KTS) TO CREATE SOME GUSTS ACROSS THE NRN COASTAL WATERS. SEAS
ACROSS THESE AREAS MAY BUILD TO 5 FT...SO WE WILL RAISE THE SCA FLAG
FOR THE 12Z TO 00Z PERIOD TO COVER THESE ENHANCED CONDITIONS. SCT
SHOWERS/TSTMS EXPECTED ON ALL WATERS TODAY WITH LOCALLY HIGHER
WINDS/SEAS. TONIGHT...THE COLD FRONT WILL CROSS THROUGH WITH SCAT
SHOWERS/TSTMS EARLY THEN IMPROVING CONDITIONS. WINDS SHIFT TO WRLY
TONIGHT THEN NW BY MORNING.
OUTLOOK...
A COLD FRONT WILL BE TRACKING ACROSS THE CSTL WATERS, EVENTUALLY
STALLING TO OUR SOUTH THROUGH MON. SEAS ARE EXPECTED TO GENL BE IN
THE 2 TO 3 FT RANGE WITH SUSTAINED WINDS GENLY UNDER 10 KT AND
GUSTS UNDER 15 KT, SO SUB-ADVISORY CONDS ARE EXPECTED THRU THE PD.
&&
.HYDROLOGY...
FLASH FLOOD WATCH FOR NORTHERN COUNTIES. UP TO 4 INCHES OF RAIN HAS
FALLEN OVERNIGHT LEAVING THIS AREA MORE SUSCEPTIBLE TO FLOODING
TODAY. ELSEWHERE WHILE THERE IS A LOWER CHANCE, ITS NOT A ZERO
CHANCE, BUT THE MESOSCALE MODELS CONTINUE TO SHOW FAIRLY PROGRESSIVE
STORMS, SO UNLESS THERE IS TRAINING, THE RISK STILL APPEARS LOWER
THAN LOCATIONS THAT HAVE BEEN ALREADY DOUSED THE PAST 24 HOURS.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...FLASH FLOOD WATCH UNTIL 10 PM EDT THIS EVENING FOR PAZ054-055-
061-062.
NJ...FLASH FLOOD WATCH UNTIL 10 PM EDT THIS EVENING FOR NJZ001-
007>010.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR ANZ450-
451.
&&
$$
SYNOPSIS...NIERENBERG
NEAR TERM...GIGI
SHORT TERM...O`HARA
LONG TERM...NIERENBERG
AVIATION...GIGI/NIERENBERG
MARINE...NIERENBERG/O`HARA
HYDROLOGY...GIGI
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
450 PM EDT FRI AUG 9 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
ISSUED AT 340 PM EDT FRI AUG 9 2013
SCATTERED SHOWERS WILL LINGER OVER SOUTHERN COUNTIES TONIGHT AS A
REMNANT BOUNDARY DRIFTS SLOWLY SOUTH OF THE OHIO RIVER. A SECONDARY
COLD FRONT WILL MOVE ACROSS THE REGION SATURDAY...WITH HIGH PRESSURE
AND DRIER AIR BUILDING INTO CENTRAL INDIANA FOR SATURDAY NIGHT AND
SUNDAY. A STRONGER COLD FRONT WILL BRING THE NEXT CHANCE FOR SHOWERS
AND THUNDERSTORMS MONDAY AND TUESDAY. COOLER AIR WILL EXPAND INTO
THE OHIO VALLEY IN THE WAKE OF THIS FRONT FOR MUCH OF THE REST OF
NEXT WEEK.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 342 PM EDT FRI AUG 9 2013
MUCH OF THE THICKER CLOUD COVER HAS SCATTERED OUT INTO A CU FIELD
THIS AFTERNOON...AS THE OLD FRONTAL BOUNDARY NOW APPEARS TO HAVE
SHIFTED SOUTH CLOSER TO THE OHIO RIVER. WITH THE INCREASING
SUNSHINE...TEMPS HAD WARMED INTO LOWER 80S OVER MUCH OF THE REGION
AS OF 19Z.
DRIER AIRMASS SLOWLY ADVECTING SOUTH INTO THE FORECAST AREA...WITH
DEWPOINTS NOW INTO THE LOWER AND MIDDLE 60S NORTH OF I-70. WHILE
DEEPER MOISTURE IS STEADILY BEING SHOVED SOUTH...REMNANT DISTURBANCE
ALOFT OVER SOUTHEAST MISSOURI WILL NEED TO BE MONITORED AS IT TRACKS
INTO THE OHIO VALLEY TONIGHT. STEERING FLOW ALOFT GENERALLY
E/NE...WHICH SHOULD BRING CONVECTION ASSOCIATED WITH THE DISTURBANCE
INTO SOUTHWEST INDIANA BY 22Z. UNLIKE THE MCV FROM LAST NIGHT...THIS
FEATURE IS WEAKER AND IS TRACKING FURTHER TO THE SOUTH.
ADDITIONALLY...INSTABILITY GRADIENT JUST GRAZES SOUTHERN FORECAST
AREA WITH ONLY SUBTLE DESTABILIZATION EXPECTED BETWEEN NOW AND
SUNSET. ONCE AGAIN...CURRENT HRRR GUIDANCE SEEMS TO HAVE CAPTURED
CONVECTION WELL AND HAVE UTILIZED IT FOR THE NEXT SEVERAL HOURS.
WILL CARRY LOW CHANCE POPS MAINLY ALONG AND SOUTH OF A SULLIVAN-
BLOOMINGTON-GREENSBURG LINE THIS EVENING...GRADUALLY ENDING FROM
WEST TO EAST OVERNIGHT. COULD SEE A FEW RUMBLES OF THUNDER OVER
EXTREME SOUTHERN COUNTIES INTO THE EVENING AS WELL.
PRESENCE OF THE DRIER AIRMASS TO THE NORTH AND LESS FAVORABLE
ATMOSPHERIC CONDITIONS SHOULD KEEP ANY APPRECIABLE RAINFALL FROM
PROGRESSING MUCH FURTHER NORTH THAN THE LINE OUTLINED. MUCH OF THE
FORECAST AREA ON THE OTHER HAND WILL BE ENCOMPASSED BY THE BROAD
MID/HIGH LEVEL CLOUD SHIELD ASSOCIATED WITH THE DISTURBANCE...LIKELY
CREATING A PERIOD WITH INCREASED CLOUD COVERAGE THROUGH THE EVENING.
AS HIGHER CLOUDS DIMINISH OVERNIGHT...MODEL SOUNDINGS SUGGEST A
FAVORABLE SETUP FOR REDEVELOPMENT OF STRATUS AND POSSIBLY SOME
PATCHY FOG.
TEMPS...MAVMOS GUIDANCE LOOKED REASONABLE CONSIDERING LOW LEVEL
THERMALS AS MOST AREAS SHOULD FALL INTO THE MID 60S.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY/...
ISSUED AT 342 PM EDT FRI AUG 9 2013
FORECAST CHALLENGES FOCUS ON PRECIP CHANCES IN THE SOUTH SATURDAY
AND ACROSS THE ENTIRE AREA ON MONDAY.
OLD BOUNDARY SHOULD STILL BE SOMEWHERE NEAR OR JUST SOUTH OF THE
OHIO RIVER SATURDAY MORNING WITH LINGERING LOW LEVEL MOISTURE
EXTENDING NORTH INTO THE FORECAST AREA. SECONDARY FRONT DROPPING
SOUTH FROM THE GREAT LAKES LIKELY TO BE LOCATED SOMEWHERE ACROSS THE
NORTHERN PART OF THE FORECAST AREA AT 12Z. THIS FRONT WILL STEADILY
PUSH SOUTH ACROSS THE FORECAST AREA THROUGH THE DAY...EVENTUALLY
DROPPING SOUTH OF THE OHIO RIVER SATURDAY NIGHT. VERY LITTLE FORCING
ALOFT ACCOMPANYING THE BOUNDARY...BUT PRESENCE OF THE LINGERING LOW
LEVEL MOISTURE OVER SOUTHERN COUNTIES COMBINED WITH WEAK INSTABILITY
MAY BE ENOUGH TO GENERATE ISOLATED CONVECTION DURING THE AFTERNOON
AND EARLY EVENING. WILL CARRY LOW CHANCE POPS SOUTH OF A TERRE
HAUTE-RUSHVILLE LINE.
DEEPER MOISTURE PLUME WILL FINALLY DEPART TO THE SOUTH OVERNIGHT
SATURDAY AS WEAK HIGH PRESSURE BUILDS INTO THE REGION. THE HIGH WILL
REMAIN CENTERED ACROSS CENTRAL INDIANA ON SUNDAY...SQUEEZED BETWEEN
AN UPPER LEVEL DISTURBANCE TRACKING INTO THE WESTERN GREAT LAKES
AND THE BACK EDGE OF THE DEEPER MOISTURE PLUME WHICH IS LIKELY TO
NOT PROGRESS MUCH FURTHER SOUTH THAN THE TENNESSEE AND LOWER OHIO
VALLEYS. WEAK INSTABILITY SHOULD LEND TOWARDS SOME CU DEVELOPMENT IN
THE AFTERNOON BUT LACK OF ANY APPRECIABLE FORCING ALOFT SHOULD KEEP
DRY CONDITIONS IN PLACE ON SUNDAY. THE HIGH WILL SHIFT EAST SUNDAY
NIGHT WITH LOW LEVEL FLOW VEERING BACK AROUND TO A W/SW DIRECTION
MONDAY. THIS WILL ALLOW THE DEEPER MOISTURE PLUME TO ADVECT BACK
NORTH INTO THE REGION ON MONDAY AND INTERACT WITH A COLD FRONT
MOVING IN FROM THE NORTHWEST. THE COMBINATION OF PRECIP WATER VALUES
BACK UP TO 1.5-2 INCHES AND MODEST INSTABILITY SHOULD LEND TO
SCATTERED CONVECTIVE DEVELOPMENT WITH THE FRONT MONDAY AFTERNOON.
TEMPS...GENERALLY LEANED TOWARDS COOLER MAVMOS THROUGH THE PERIOD AS
THE NAM SEEMS TO BE HANGING LOW LEVEL MOISTURE UP A BIT TOO MUCH.
HIGH TEMPS SHOULD REMAIN LARGELY IN THE 80S OVER THE WEEKEND AS LOW
LEVEL THERMALS NOT NEARLY AS COOL AS WERE PROGGED JUST A FEW DAYS
AGO. EDGE WILL BE TAKEN OFF THE HUMIDITY LEVELS HOWEVER WITH COOLER
NIGHTS. POTENTIAL IS THERE FOR TEMPS TO FALL INTO THE MID AND UPPER
50S IN A NUMBER OF LOCATIONS SUNDAY MORNING.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
ISSUED AT 232 PM EDT FRI AUG 9 2013
MODELS ARE SIMILAR ENOUGH THAT THE ALLBLEND INITIALIZATION CAN BE
USED FOR MOST ITEMS IN THE LONG TERM.
AN UPPER TROUGH WILL CONTINUE ACROSS THE AREA THROUGH THE LONG TERM.
THIS WILL KEEP TEMPERATURES BELOW AVERAGE THROUGH THE PERIOD.
AS THE COLD FRONT USHERS IN THE COOL CANADIAN AIR MONDAY NIGHT INTO
TUESDAY SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE...MAINLY MONDAY
NIGHT. AFTERWARD HIGH PRESSURE WILL BUILD IN AND PROVIDE DRY
CONDITIONS TUESDAY NIGHT THROUGH FRIDAY.
&&
.AVIATION /DISCUSSION FOR THE 09/2100Z TAF UPDATE/...
ISSUED AT 448 PM EDT FRI AUG 9 2013
UPDATE...
NO CHANGES.
PREVIOUS DISCUSSION...
ANY LINGERING MVFR CEILINGS SHOULD LIFT TO VFR VERY EARLY IN THE
PERIOD. VFR WILL THEN RULE UNTIL AROUND 06Z WHEN MVFR FOG/CEILINGS
WILL FORM WITH THE POTENTIAL FOR IFR. VFR RETURNS LATE SATURDAY
MORNING.
SATELLITE SHOWS STRATUS CONTINUING TO BREAK UP ALLOWING HEATING TO
LIFT THE CEILINGS. STILL EXPECT SCATTERED TO BROKEN CU THROUGH THE
AFTERNOON. LOOKS LIKE CHANCES FOR CONVECTION WILL HOLD OFF UNTIL
LATE AFTERNOON AND MAINLY FOR KHUF/KBMG. CHANCES ARE TOO LOW TO
MENTION IN TAFS AT THE MOMENT.
LINGERING LOW LEVEL MOISTURE WILL LEAD TO FOG DEVELOPMENT WITH SOME
STRATUS LIKELY TONIGHT. WILL GO MVFR FOR NOW...BUT POTENTIAL FOR IFR
IS THERE. WILL USE BCFG TO HINT AT THAT POSSIBILITY. FOG/STRATUS
WILL BURN OFF SATURDAY MORNING.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM....50
AVIATION...50/TDUD
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
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AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
343 PM EDT FRI AUG 9 2013
.UPDATE...
THE SYNOPSIS...NEAR TERM AND SHORT TERM SECTIONS HAVE BEEN UPDATED
BELOW.
&&
.SYNOPSIS...
ISSUED AT 340 PM EDT FRI AUG 9 2013
SCATTERED SHOWERS WILL LINGER OVER SOUTHERN COUNTIES TONIGHT AS A
REMNANT BOUNDARY DRIFTS SLOWLY SOUTH OF THE OHIO RIVER. A SECONDARY
COLD FRONT WILL MOVE ACROSS THE REGION SATURDAY...WITH HIGH PRESSURE
AND DRIER AIR BUILDING INTO CENTRAL INDIANA FOR SATURDAY NIGHT AND
SUNDAY. A STRONGER COLD FRONT WILL BRING THE NEXT CHANCE FOR SHOWERS
AND THUNDERSTORMS MONDAY AND TUESDAY. COOLER AIR WILL EXPAND INTO
THE OHIO VALLEY IN THE WAKE OF THIS FRONT FOR MUCH OF THE REST OF
NEXT WEEK.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 342 PM EDT FRI AUG 9 2013
MUCH OF THE THICKER CLOUD COVER HAS SCATTERED OUT INTO A CU FIELD
THIS AFTERNOON...AS THE OLD FRONTAL BOUNDARY NOW APPEARS TO HAVE
SHIFTED SOUTH CLOSER TO THE OHIO RIVER. WITH THE INCREASING
SUNSHINE...TEMPS HAD WARMED INTO LOWER 80S OVER MUCH OF THE REGION
AS OF 19Z.
DRIER AIRMASS SLOWLY ADVECTING SOUTH INTO THE FORECAST AREA...WITH
DEWPOINTS NOW INTO THE LOWER AND MIDDLE 60S NORTH OF I-70. WHILE
DEEPER MOISTURE IS STEADILY BEING SHOVED SOUTH...REMNANT DISTURBANCE
ALOFT OVER SOUTHEAST MISSOURI WILL NEED TO BE MONITORED AS IT TRACKS
INTO THE OHIO VALLEY TONIGHT. STEERING FLOW ALOFT GENERALLY
E/NE...WHICH SHOULD BRING CONVECTION ASSOCIATED WITH THE DISTURBANCE
INTO SOUTHWEST INDIANA BY 22Z. UNLIKE THE MCV FROM LAST NIGHT...THIS
FEATURE IS WEAKER AND IS TRACKING FURTHER TO THE SOUTH.
ADDITIONALLY...INSTABILITY GRADIENT JUST GRAZES SOUTHERN FORECAST
AREA WITH ONLY SUBTLE DESTABILIZATION EXPECTED BETWEEN NOW AND
SUNSET. ONCE AGAIN...CURRENT HRRR GUIDANCE SEEMS TO HAVE CAPTURED
CONVECTION WELL AND HAVE UTILIZED IT FOR THE NEXT SEVERAL HOURS.
WILL CARRY LOW CHANCE POPS MAINLY ALONG AND SOUTH OF A SULLIVAN-
BLOOMINGTON-GREENSBURG LINE THIS EVENING...GRADUALLY ENDING FROM
WEST TO EAST OVERNIGHT. COULD SEE A FEW RUMBLES OF THUNDER OVER
EXTREME SOUTHERN COUNTIES INTO THE EVENING AS WELL.
PRESENCE OF THE DRIER AIRMASS TO THE NORTH AND LESS FAVORABLE
ATMOSPHERIC CONDITIONS SHOULD KEEP ANY APPRECIABLE RAINFALL FROM
PROGRESSING MUCH FURTHER NORTH THAN THE LINE OUTLINED. MUCH OF THE
FORECAST AREA ON THE OTHER HAND WILL BE ENCOMPASSED BY THE BROAD
MID/HIGH LEVEL CLOUD SHIELD ASSOCIATED WITH THE DISTURBANCE...LIKELY
CREATING A PERIOD WITH INCREASED CLOUD COVERAGE THROUGH THE EVENING.
AS HIGHER CLOUDS DIMINISH OVERNIGHT...MODEL SOUNDINGS SUGGEST A
FAVORABLE SETUP FOR REDEVELOPMENT OF STRATUS AND POSSIBLY SOME
PATCHY FOG.
TEMPS...MAVMOS GUIDANCE LOOKED REASONABLE CONSIDERING LOW LEVEL
THERMALS AS MOST AREAS SHOULD FALL INTO THE MID 60S.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY/...
ISSUED AT 342 PM EDT FRI AUG 9 2013
FORECAST CHALLENGES FOCUS ON PRECIP CHANCES IN THE SOUTH SATURDAY
AND ACROSS THE ENTIRE AREA ON MONDAY.
OLD BOUNDARY SHOULD STILL BE SOMEWHERE NEAR OR JUST SOUTH OF THE
OHIO RIVER SATURDAY MORNING WITH LINGERING LOW LEVEL MOISTURE
EXTENDING NORTH INTO THE FORECAST AREA. SECONDARY FRONT DROPPING
SOUTH FROM THE GREAT LAKES LIKELY TO BE LOCATED SOMEWHERE ACROSS THE
NORTHERN PART OF THE FORECAST AREA AT 12Z. THIS FRONT WILL STEADILY
PUSH SOUTH ACROSS THE FORECAST AREA THROUGH THE DAY...EVENTUALLY
DROPPING SOUTH OF THE OHIO RIVER SATURDAY NIGHT. VERY LITTLE FORCING
ALOFT ACCOMPANYING THE BOUNDARY...BUT PRESENCE OF THE LINGERING LOW
LEVEL MOISTURE OVER SOUTHERN COUNTIES COMBINED WITH WEAK INSTABILITY
MAY BE ENOUGH TO GENERATE ISOLATED CONVECTION DURING THE AFTERNOON
AND EARLY EVENING. WILL CARRY LOW CHANCE POPS SOUTH OF A TERRE
HAUTE-RUSHVILLE LINE.
DEEPER MOISTURE PLUME WILL FINALLY DEPART TO THE SOUTH OVERNIGHT
SATURDAY AS WEAK HIGH PRESSURE BUILDS INTO THE REGION. THE HIGH WILL
REMAIN CENTERED ACROSS CENTRAL INDIANA ON SUNDAY...SQUEEZED BETWEEN
AN UPPER LEVEL DISTURBANCE TRACKING INTO THE WESTERN GREAT LAKES
AND THE BACK EDGE OF THE DEEPER MOISTURE PLUME WHICH IS LIKELY TO
NOT PROGRESS MUCH FURTHER SOUTH THAN THE TENNESSEE AND LOWER OHIO
VALLEYS. WEAK INSTABILITY SHOULD LEND TOWARDS SOME CU DEVELOPMENT IN
THE AFTERNOON BUT LACK OF ANY APPRECIABLE FORCING ALOFT SHOULD KEEP
DRY CONDITIONS IN PLACE ON SUNDAY. THE HIGH WILL SHIFT EAST SUNDAY
NIGHT WITH LOW LEVEL FLOW VEERING BACK AROUND TO A W/SW DIRECTION
MONDAY. THIS WILL ALLOW THE DEEPER MOISTURE PLUME TO ADVECT BACK
NORTH INTO THE REGION ON MONDAY AND INTERACT WITH A COLD FRONT
MOVING IN FROM THE NORTHWEST. THE COMBINATION OF PRECIP WATER VALUES
BACK UP TO 1.5-2 INCHES AND MODEST INSTABILITY SHOULD LEND TO
SCATTERED CONVECTIVE DEVELOPMENT WITH THE FRONT MONDAY AFTERNOON.
TEMPS...GENERALLY LEANED TOWARDS COOLER MAVMOS THROUGH THE PERIOD AS
THE NAM SEEMS TO BE HANGING LOW LEVEL MOISTURE UP A BIT TOO MUCH.
HIGH TEMPS SHOULD REMAIN LARGELY IN THE 80S OVER THE WEEKEND AS LOW
LEVEL THERMALS NOT NEARLY AS COOL AS WERE PROGGED JUST A FEW DAYS
AGO. EDGE WILL BE TAKEN OFF THE HUMIDITY LEVELS HOWEVER WITH COOLER
NIGHTS. POTENTIAL IS THERE FOR TEMPS TO FALL INTO THE MID AND UPPER
50S IN A NUMBER OF LOCATIONS SUNDAY MORNING.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
ISSUED AT 232 PM EDT FRI AUG 9 2013
MODELS ARE SIMILAR ENOUGH THAT THE ALLBLEND INITIALIZATION CAN BE
USED FOR MOST ITEMS IN THE LONG TERM.
AN UPPER TROUGH WILL CONTINUE ACROSS THE AREA THROUGH THE LONG TERM.
THIS WILL KEEP TEMPERATURES BELOW AVERAGE THROUGH THE PERIOD.
AS THE COLD FRONT USHERS IN THE COOL CANADIAN AIR MONDAY NIGHT INTO
TUESDAY SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE...MAINLY MONDAY
NIGHT. AFTERWARD HIGH PRESSURE WILL BUILD IN AND PROVIDE DRY
CONDITIONS TUESDAY NIGHT THROUGH FRIDAY.
&&
.AVIATION /DISCUSSION FOR THE 091800Z TAFS/...
ISSUED AT 1259 PM EDT FRI AUG 9 2013
ANY LINGERING MVFR CEILINGS SHOULD LIFT TO VFR VERY EARLY IN THE
PERIOD. VFR WILL THEN RULE UNTIL AROUND 06Z WHEN MVFR FOG/CEILINGS
WILL FORM WITH THE POTENTIAL FOR IFR. VFR RETURNS LATE SATURDAY
MORNING.
SATELLITE SHOWS STRATUS CONTINUING TO BREAK UP ALLOWING HEATING TO
LIFT THE CEILINGS. STILL EXPECT SCATTERED TO BROKEN CU THROUGH THE
AFTERNOON. LOOKS LIKE CHANCES FOR CONVECTION WILL HOLD OFF UNTIL
LATE AFTERNOON AND MAINLY FOR KHUF/KBMG. CHANCES ARE TOO LOW TO
MENTION IN TAFS AT THE MOMENT.
LINGERING LOW LEVEL MOISTURE WILL LEAD TO FOG DEVELOPMENT WITH SOME
STRATUS LIKELY TONIGHT. WILL GO MVFR FOR NOW...BUT POTENTIAL FOR IFR
IS THERE. WILL USE BCFG TO HINT AT THAT POSSIBILITY. FOG/STRATUS
WILL BURN OFF SATURDAY MORNING.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM....50
AVIATION...50
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
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AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1254 PM CDT FRI AUG 9 2013
.UPDATE...
ISSUED AT 1247 PM CDT FRI AUG 9 2013
WEAK COLD FRONT CONTINUES TO MAKE STEADY PROGRESS INTO THE DVN CWA
AND EXTENDED FROM NEAR FREEPORT TO JUST SOUTH OF IOWA CITY. THERE
IS A NARROW BAND OF LOWER CLOUDS BEHIND THE FRONT OTHERWISE MID
AND HIGH LEVEL CLOUDS WERE OVER THE CWA. HIGH TEMPERATURES STILL
LOOK ON TARGET TO BE IN THE UPPER 70S TO LOWER 80S AT MOST LOCATIONS.
NO SHOWERS HAVE POPPED UP AS OF YET BUT THE RAPID REFRESH STILL
SUGGESTS ISOLATED SHOWERS OR SPRINKLES THIS AFTERNOON NEAR THE FRONT.
UPDATE ISSUED AT 1055 AM CDT FRI AUG 9 2013
WEAK COLD FRONT WAS NEARING OUR FAR NW CWA BUT THE MAIN DYNAMICS
ASSOCIATED WITH AN UPPER LEVEL TROUGH WAS WELL TO OUR NORTH. WILL
CONTINUE WITH THE RAPID REFRESH MESO MODEL OF ONLY ISOLATED
SHOWERS OR SPRINKLES ACCOMPANYING THE FRONT AS IT TRACKS SOUTHEAST
ACROSS THE CWA THROUGH THE AFTERNOON. MAINLY MID/HIGH LEVEL CLOUDS
WILL BE OVER THE CWA. CURRENT TEMPERATURES RUNNING SLIGHTLY HIGHER
THAN FORECAST AT SOME LOCATIONS BUT ALL IN ALL THE GOING FORECAST
HIGHS LOOK REASONABLE...MAINLY IN THE UPPER 70S TO LOWER 80S.
FANTASTIC WEATHER EXPECTED TONIGHT AND SATURDAY AS HIGH PRESSURE
BUILDS INTO THE REGION. TEMPERATURES AND HUMIDITY LEVELS WILL BE
VERY COMFORTABLE FOR MID AUGUST.
MEANWHILE...A BAND OF RAIN AND A FEW THUNDERSTORMS WAS LOCATED
ACROSS EASTERN KS INTO CENTRAL MO WHICH WAS OCCURRING ALONG AN 850
MB FRONTAL BOUNDARY. HOWEVER...THAT WILL REMAIN WELL TO THE SOUTH
OF THE DVN CWA.
UPDATE ISSUED AT 642 AM CDT FRI AUG 9 2013
SHALLOW PATCHY GROUND FOG HAS DEVELOPED ALONG/EAST OF THE
MISSISSIPPI IN WEST CENTRAL ILLINOIS. THE FEW OBS REPORTING THIS
FOG DO SHOW IT IS LOCALLY DENSE AT TIMES. WITH THE SUN ALREADY
UP...CONDITIONS SHOULD BEGIN TO IMPROVE OVER THE NEXT 90 MINUTES
SO NO HEADLINE IS BEING CONSIDERED.
THE SPRINKLES AND ISOLATED SHOWERS OVER CENTRAL/SOUTHERN IOWA HAVE
DISSIPATED AS THE FORCING WEAKENED. ALONG THE MN/IA BORDER THIS
CONVECTION IS ALSO WEAKENING AS LIFT AND CONVERGENCE WEAKENS. THE
FRONTAL PASSAGE ACROSS THE AREA IS EXPECTED TO BE MAINLY DRY DUE
TO WEAK FORCING AND NOT MUCH IN THE WAY OF MOISTURE.
HOWEVER...ISOLATED WEAK DIURNAL SPRINKLES/SHOWERS CANNOT BE
ENTIRELY RULED OUT DUE TO THE TIMING OF THE FRONTAL PASSAGE. IF
DIURNAL CONVECTION DEVELOPS IT WILL DISSIPATE SHORTLY AFTER SUNSET.
&&
.SYNOPSIS...
ISSUED AT 303 AM CDT FRI AUG 9 2013
06Z SFC ANALYSIS HAS WEAK LOWS ASSOCIATED WITH A FRONTAL BOUNDARY IN
THE OHIO VALLEY WITH A THUNDERSTORM COMPLEX ACROSS OKLAHOMA. A WEAK
FRONT/BOUNDARY RAN FROM EASTERN LAKE SUPERIOR...TO KYKN...AND THEN
ACROSS SOUTHERN SOUTH DAKOTA. RADAR HAS WEAK RETURNS ACROSS CENTRAL
IOWA MAINLY IN THE FORM OF SPRINKLES AND SLIGHTLY STRONGER RETURNS
ACROSS NORTHERN IOWA NEAR THE BOUNDARY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 303 AM CDT FRI AUG 9 2013
THE WEAK RETURNS ACROSS CENTRAL AND SOUTHERN IOWA IS OCCURRING FROM
A MID LEVEL CLOUD DECK AND IS LIKELY SPRINKLES. THE BETTER RADAR
RETURNS ALONG THE MN/IA BORDER IS IN AN AREA OF BETTER LIFT.
HOWEVER...THIS LIFT IS PROGGED TO WEAKEN THROUGH SUNRISE PER TRENDS
FROM THE RAP AND OTHER MODELS. RECENT RADAR TRENDS SEEM TO SUPPORT
THIS SCENARIO WITH NOT ONLY THE NORTHERN RADAR RETURNS BUT THE
SOUTHERN RADAR RETURNS.
THUS MAYBE SOME SPRINKLES MAY ENTER THE FAR WESTERN/NORTHWEST PARTS
OF THE CWFA PRIOR TO SUNRISE BEFORE DISSIPATING.
THE WEAK FRONT/BOUNDARY SLOWLY MOVES THROUGH THE CWFA DURING THE
DAY. LIFT IS VERY WEAK AND THE BETTER MOISTURE IS SOUTH OF THE AREA.
THUS ISOLATED SPRINKLES ARE THE MORE PROBABLE PRECIPITATION TYPE
DURING THE DAY. POSSIBLY A COUPLE OF ISOLATED DIURNAL SHOWERS MAY
DEVELOP DURING THE AFTERNOON WHEN HEATING IS THE STRONGEST.
TONIGHT...ANY SPRINKLES/DIURNAL SHOWERS THAT DEVELOP WILL DISSIPATE
WITH SUNSET LEAVING THE REMAINDER OF THE NIGHT DRY AS HIGH PRESSURE
BUILDS INTO THE MIDWEST. THE MCS TOOL POINTS TO THE BETTER SUPPORT
BEING SOUTH OF THE CWFA WHICH IS WHERE THE BETTER MOISTURE IS
LOCATED.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 303 AM CDT FRI AUG 9 2013
MAINLY DRY WITH NEAR TO SLIGHTLY BELOW NORMAL TEMPS AS NORTHWEST
FLOW ALOFT REMAINS IN PLACE OVER THE REGION.
SAT-SAT NGT... MORE FANTASTIC WEATHER FOR OUTDOOR ACTIVITIES WITH
SURFACE TO 850 MB HIGH PRESSURE RIDGE PROVIDING LIGHT NORTHERLY
WINDS USHERING IN DRIER AIR AND COMFORTABLE HUMIDITY WITH HIGHS
MAINLY IN RANGE OF 77-83F. LOWS SAT NGT MAINLY IN RANGE OF 57-63F
WITH SOME INTERVALS OF MID/HIGH CLOUDS FROM UPSTREAM CONVECTION
PARTS OF SD/MN/NW-N IA ATTENDANT TO SHORTWAVE AND ELEVATED WARM
MOIST ADVECTION NORTH OF SURFACE BOUNDARY.
SUN-MON... WEAK SHORTWAVE AND FRONTAL BOUNDARY TO RESULT IN CHC
OF PCPN. LACK OF DEEP MOISTURE AND WEAK FORCING SUGGESTED ATTIM
SUPPORTIVE OF MOSTLY LIGHT QPF AMOUNTS. PCPN CHC MAY HOLD OFF
UNTIL MON ACROSS THE SOUTHERN CWA WITH CONTINUED INFLUX OF
DRIER AIR FROM DEPARTING HIGH. BUT THEN ON MON... MAY SEE PCPN
SHIFT FROM THE NORTH AND FOCUS MORE ACROSS SOUTHERN CWA DEPENDING
ON TIMING OF BOUNDARY. EXPECT TEMPS TO RECOVER ON SUN TO AROUND
NORMAL WITH DEVELOPING SOUTH WINDS AND DEEPER MIXING TO JUST ABOVE
850 MB SUPPORTIVE OF HIGHS IN THE LOW TO MID 80S. HOWEVER... DEBRIS
CLOUDS IN FAR NORTH SUN COULD LIMIT HIGHS THERE IN THE 70S ALONG/N
OF HWY 20. SUN NGT WITH CLOUDS AND PRE-FRONTAL SOUTH WINDS SHOULD
YIELD MILDER LOWS IN THE 60S. MON WILL BE FEW TO SEVERAL DEGS
COOLER ON HIGHS WITH MAINLY UPPER 70S TO LOWER 80S DUE TO CLOUDS
AND FRONTAL PASSAGE.
TUE-THU... HIGH PRESSURE TO BECOME RE-ESTABLISHED ACROSS THE REGION
AND LIKELY REMAIN DOMINANT FEATURE THROUGH THE PERIOD KEEPING
TEMPS BELOW NORMAL AND DRY CONDITIONS WITH VERY COMFORTABLE HUMIDITY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1247 PM CDT FRI AUG 9 2013
MAINLY VFR CONDS THIS AFTERNOON. THERE IS A NARROW BAND OF OCNL
MVFR CIGS BEHIND A WEAK COLD FRONT DROPPING SOUTHWARD ACROSS
EASTERN IA. THE FRONT WILL MOVE ACROSS THE TAF SITES THIS AFTERNOON
WITH ONLY ISOLATED SHOWERS OR SPRINKLES ACCOMPANYING THE FRONT.
VFR CONDS WITH SKC TONIGHT AND SATURDAY AS HIGH PRESSURE BUILDS
INTO THE REGION. VARIABLE WINDS BECOMING NORTHWEST BEHIND THE
FRONT. NORTH WINDS TONIGHT AND SATURDAY. WIND SPEEDS WILL BE LESS
THAN 10 KNOTS.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...HAASE
SYNOPSIS...08
SHORT TERM...08
LONG TERM...05
AVIATION...HAASE
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1234 PM CDT FRI AUG 9 2013
.SHORT TERM.../TODAY /...
ISSUED AT 313 AM CDT FRI AUG 9 2013
WEAK COLD FRONTAL BOUNDARY EXTENDING FROM FROM MN INTO NWRN IA INTO
KS WILL MOVE SOUTHEAST AND EXIT THE CWA BY AROUND MID DAY. SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS OCCURRING ALONG THE FRONT WILL
CONTINUE TO MOVE ESEWD WITH THE FRONT HRRR HAS A PRETTY DECENT
HANDLE ON THE PRECIP AND SUGGESTS THE PRECIP WILL BE OUT OF THE CWA
BY AROUND 18Z. HIGH PRESSURE WILL BEGIN BUILDING INTO THE STATE
THIS AFTERNOON FROM THE NORTHWEST.
.LONG TERM.../TONIGHT THROUGH THURSDAY/...
ISSUED AT 313 AM CDT FRI AUG 9 2013
SIMILAR CHALLENGES COMING UP COMPARED TO PAST FEW DAYS. APPROACHING
SHORT WAVES AND SYNOPTIC FEATURES REMAIN RATHER WEAK GIVEN TIME OF
YEAR AND QUESTIONS REVOLVING AROUND COVERAGE AND CHANCES FOR RAIN IN
THE FORECAST. FOR NOW...WEAK BOUNDARY WILL BE SOUTH OF THE REGION BY
THIS EVENING AND DRY WEATHER EXPECTED THROUGH LATE SATURDAY NIGHT.
FINALLY ON SUNDAY ANOTHER NORTHERN STREAM WAVE WILL ATTEMPT TO CROSS
THE AREA WITH SOME MOISTURE ASSOCIATED WITH IT. THIS WILL ONCE AGAIN
BRING CHANCES FOR SHOWERS AND THUNDERSTORMS TO THE AREA SUNDAY INTO
MONDAY AFTERNOON. FOLLOWING THAT HIGH PRESSURE WILL DROP SOUTH OUT
OF CANADA AND KEEP TEMPERATURES COMFORTABLE IN THE UPPER 70S TO
LOWER 80S WITH SLIGHTLY COOLER READINGS OVER THE NORTH. OVERALL
QUITE PLEASANT FOR AUGUST...THOUGH A BIT BELOW NORMAL. MOST OF THE
MED RANGE MODELS SUGGEST THAT THE HIGH OVER THE GREAT LAKES WILL
REMAIN ANCHORED THERE UNTIL MID TO LATE NEXT WEEK. FOR THE MOST PART
OUR WEATHER WILL REMAIN RATHER UNEVENTFUL WITH DRIER AND COOLER THAN
NORMAL CONDITIONS.
&&
.AVIATION...09/18Z
ISSUED AT 1231 PM CDT FRI AUG 9 2013
SURFACE FRONT CURRENTLY PASSING THROUGH SOUTHERN IOWA WILL EXIT
THE STATE BY LATE AFTERNOON. ISOLATED STORMS ARE EXPECTED ALONG
THIS BOUNDARY AS IT MOVES SOUTHEAST WITH WINDS GENERALLY NORTH TO
NORTHEAST BEHIND THE BOUNDARY. WIDESPREAD VFR CONDITIONS ARE
EXPECTED OVERNIGHT INTO SATURDAY MORNING WITH UNRESTRICTED VSBYS
AND ANY CEILINGS REMAINING AT OR ABOVE TWELVE THOUSAND FEET.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...MS AUG 13
LONG TERM...REV
AVIATION...COGIL
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1102 AM CDT FRI AUG 9 2013
.UPDATE...
ISSUED AT 1055 AM CDT FRI AUG 9 2013
WEAK COLD FRONT WAS NEARING OUR FAR NW CWA BUT THE MAIN DYNAMICS
ASSOCIATED WITH AN UPPER LEVEL TROUGH WAS WELL TO OUR NORTH. WILL
CONTINUE WITH THE RAPID REFRESH MESO MODEL OF ONLY ISOLATED
SHOWERS OR SPRINKLES ACCOMPANYING THE FRONT AS IT TRACKS SOUTHEAST
ACROSS THE CWA THROUGH THE AFTERNOON. MAINLY MID/HIGH LEVEL CLOUDS
WILL BE OVER THE CWA. CURRENT TEMPERATURES RUNNING SLIGHTLY HIGHER
THAN FORECAST AT SOME LOCATIONS BUT ALL IN ALL THE GOING FORECAST
HIGHS LOOK REASONABLE...MAINLY IN THE UPPER 70S TO LOWER 80S.
FANTASTIC WEATHER EXPECTED TONIGHT AND SATURDAY AS HIGH PRESSURE
BUILDS INTO THE REGION. TEMPERATURES AND HUMIDITY LEVELS WILL BE
VERY COMFORTABLE FOR MID AUGUST.
MEANWHILE...A BAND OF RAIN AND A FEW THUNDERSTORMS WAS LOCATED
ACROSS EASTERN KS INTO CENTRAL MO WHICH WAS OCCURRING ALONG AN 850
MB FRONTAL BOUNDARY. HOWEVER...THAT WILL REMAIN WELL TO THE SOUTH
OF THE DVN CWA.
UPDATE ISSUED AT 642 AM CDT FRI AUG 9 2013
SHALLOW PATCHY GROUND FOG HAS DEVELOPED ALONG/EAST OF THE
MISSISSIPPI IN WEST CENTRAL ILLINOIS. THE FEW OBS REPORTING THIS
FOG DO SHOW IT IS LOCALLY DENSE AT TIMES. WITH THE SUN ALREADY
UP...CONDITIONS SHOULD BEGIN TO IMPROVE OVER THE NEXT 90 MINUTES
SO NO HEADLINE IS BEING CONSIDERED.
THE SPRINKLES AND ISOLATED SHOWERS OVER CENTRAL/SOUTHERN IOWA HAVE
DISSIPATED AS THE FORCING WEAKENED. ALONG THE MN/IA BORDER THIS
CONVECTION IS ALSO WEAKENING AS LIFT AND CONVERGENCE WEAKENS. THE
FRONTAL PASSAGE ACROSS THE AREA IS EXPECTED TO BE MAINLY DRY DUE
TO WEAK FORCING AND NOT MUCH IN THE WAY OF MOISTURE.
HOWEVER...ISOLATED WEAK DIURNAL SPRINKLES/SHOWERS CANNOT BE
ENTIRELY RULED OUT DUE TO THE TIMING OF THE FRONTAL PASSAGE. IF
DIURNAL CONVECTION DEVELOPS IT WILL DISSIPATE SHORTLY AFTER SUNSET.
&&
.SYNOPSIS...
ISSUED AT 303 AM CDT FRI AUG 9 2013
06Z SFC ANALYSIS HAS WEAK LOWS ASSOCIATED WITH A FRONTAL BOUNDARY IN
THE OHIO VALLEY WITH A THUNDERSTORM COMPLEX ACROSS OKLAHOMA. A WEAK
FRONT/BOUNDARY RAN FROM EASTERN LAKE SUPERIOR...TO KYKN...AND THEN
ACROSS SOUTHERN SOUTH DAKOTA. RADAR HAS WEAK RETURNS ACROSS CENTRAL
IOWA MAINLY IN THE FORM OF SPRINKLES AND SLIGHTLY STRONGER RETURNS
ACROSS NORTHERN IOWA NEAR THE BOUNDARY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 303 AM CDT FRI AUG 9 2013
THE WEAK RETURNS ACROSS CENTRAL AND SOUTHERN IOWA IS OCCURRING FROM
A MID LEVEL CLOUD DECK AND IS LIKELY SPRINKLES. THE BETTER RADAR
RETURNS ALONG THE MN/IA BORDER IS IN AN AREA OF BETTER LIFT.
HOWEVER...THIS LIFT IS PROGGED TO WEAKEN THROUGH SUNRISE PER TRENDS
FROM THE RAP AND OTHER MODELS. RECENT RADAR TRENDS SEEM TO SUPPORT
THIS SCENARIO WITH NOT ONLY THE NORTHERN RADAR RETURNS BUT THE
SOUTHERN RADAR RETURNS.
THUS MAYBE SOME SPRINKLES MAY ENTER THE FAR WESTERN/NORTHWEST PARTS
OF THE CWFA PRIOR TO SUNRISE BEFORE DISSIPATING.
THE WEAK FRONT/BOUNDARY SLOWLY MOVES THROUGH THE CWFA DURING THE
DAY. LIFT IS VERY WEAK AND THE BETTER MOISTURE IS SOUTH OF THE AREA.
THUS ISOLATED SPRINKLES ARE THE MORE PROBABLE PRECIPITATION TYPE
DURING THE DAY. POSSIBLY A COUPLE OF ISOLATED DIURNAL SHOWERS MAY
DEVELOP DURING THE AFTERNOON WHEN HEATING IS THE STRONGEST.
TONIGHT...ANY SPRINKLES/DIURNAL SHOWERS THAT DEVELOP WILL DISSIPATE
WITH SUNSET LEAVING THE REMAINDER OF THE NIGHT DRY AS HIGH PRESSURE
BUILDS INTO THE MIDWEST. THE MCS TOOL POINTS TO THE BETTER SUPPORT
BEING SOUTH OF THE CWFA WHICH IS WHERE THE BETTER MOISTURE IS
LOCATED.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 303 AM CDT FRI AUG 9 2013
MAINLY DRY WITH NEAR TO SLIGHTLY BELOW NORMAL TEMPS AS NORTHWEST
FLOW ALOFT REMAINS IN PLACE OVER THE REGION.
SAT-SAT NGT... MORE FANTASTIC WEATHER FOR OUTDOOR ACTIVITIES WITH
SURFACE TO 850 MB HIGH PRESSURE RIDGE PROVIDING LIGHT NORTHERLY
WINDS USHERING IN DRIER AIR AND COMFORTABLE HUMIDITY WITH HIGHS
MAINLY IN RANGE OF 77-83F. LOWS SAT NGT MAINLY IN RANGE OF 57-63F
WITH SOME INTERVALS OF MID/HIGH CLOUDS FROM UPSTREAM CONVECTION
PARTS OF SD/MN/NW-N IA ATTENDANT TO SHORTWAVE AND ELEVATED WARM
MOIST ADVECTION NORTH OF SURFACE BOUNDARY.
SUN-MON... WEAK SHORTWAVE AND FRONTAL BOUNDARY TO RESULT IN CHC
OF PCPN. LACK OF DEEP MOISTURE AND WEAK FORCING SUGGESTED ATTIM
SUPPORTIVE OF MOSTLY LIGHT QPF AMOUNTS. PCPN CHC MAY HOLD OFF
UNTIL MON ACROSS THE SOUTHERN CWA WITH CONTINUED INFLUX OF
DRIER AIR FROM DEPARTING HIGH. BUT THEN ON MON... MAY SEE PCPN
SHIFT FROM THE NORTH AND FOCUS MORE ACROSS SOUTHERN CWA DEPENDING
ON TIMING OF BOUNDARY. EXPECT TEMPS TO RECOVER ON SUN TO AROUND
NORMAL WITH DEVELOPING SOUTH WINDS AND DEEPER MIXING TO JUST ABOVE
850 MB SUPPORTIVE OF HIGHS IN THE LOW TO MID 80S. HOWEVER... DEBRIS
CLOUDS IN FAR NORTH SUN COULD LIMIT HIGHS THERE IN THE 70S ALONG/N
OF HWY 20. SUN NGT WITH CLOUDS AND PRE-FRONTAL SOUTH WINDS SHOULD
YIELD MILDER LOWS IN THE 60S. MON WILL BE FEW TO SEVERAL DEGS
COOLER ON HIGHS WITH MAINLY UPPER 70S TO LOWER 80S DUE TO CLOUDS
AND FRONTAL PASSAGE.
TUE-THU... HIGH PRESSURE TO BECOME RE-ESTABLISHED ACROSS THE REGION
AND LIKELY REMAIN DOMINANT FEATURE THROUGH THE PERIOD KEEPING
TEMPS BELOW NORMAL AND DRY CONDITIONS WITH VERY COMFORTABLE HUMIDITY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 1055 AM CDT FRI AUG 9 2013
VFR CONDS THROUGH TONIGHT. A WEAK COLD FRONT WILL MOVE ACROSS THE
TAF SITES THIS AFTERNOON WITH ONLY ISOLATED SHOWERS OR SPRINKLES
ACCOMPANYING THE FRONT. VARIABLE WINDS BECOMING NORTHWEST BEHIND
THE FRONT. NORTH WINDS TONIGHT AS HIGH PRESSURE BEGINS BUILDING
INTO THE REGION. WIND SPEEDS WILL BE LESS THAN 10 KNOTS.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...HAASE
SYNOPSIS...08
SHORT TERM...08
LONG TERM...05
AVIATION...HAASE
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
536 PM EDT Fri Aug 9 2013
...Forecast Update...
Issued at 533 PM EDT Fri Aug 9 2013
Updated the grids to reflect higher coverage of showers and storms
across SW portions of the CWA. Issued a Flood Advisory for areas
around Bowling Green as some training of showers and storms with
rainfall rates over 2 inches per hour at times will overspread the
area. Will need to watch for Flash Flood Warnings in the region over
the next couple of hours. Will also keep our eye on a cluster of
storms moving into the western fringes of our CWA in a couple of
hours. A few severe reports have come from the strongest storm,
however expect a weakening trend as the cluster moves in. Overall,
will mention numerous showers and storms early this evening in areas
where the biggest clusters are located, with isolated to scattered
coverage elsewhere. Please be aware that very heavy rainfall is
likely with any shower or storm and quick ponding of water on
roadways will occur.
.SHORT TERM (Now through Sunday)...
Issued at 305 PM EDT Fri Aug 9 2013
A line of showers and thunderstorms have begun to form along the
frontal boundary, currently draped along the Ohio River. As has been
the case this week, these are efficient rain producers, dumping a
lot of rain in a short amount of time. Traffic cameras in the
Louisville metro along with obs from SDF confirm the reduced
visibilities accompanying these cells. Thankfully, the line has been
moving relatively quickly off to the east-southeast so unless the
line really fills in, setting up a potential training effect,
flooding shouldn`t be a major concern, especially in north-central
KY where the rain has been much more hit and miss as of late. If it
is able to hold together and makes its way into the Bluegrass
region, there could be some localized problems since FFG is much
lower there due to the recent heavy rains and already saturated
soils. Unfortunately, the models aren`t handling it very well with
the exception of the latest NAM (but its performance this week has
been less than stellar) so its tough to get a solid idea of how this
will play out. While the HRRR doesn`t necessarily depict it well,
this has been one of the top performing models under this regime
and its showing scattered cells developing across much of the center
of the commonwealth. Later tonight, a mid-level wave traverses
through and the HRRR grabs onto it, bringing a cluster of showers
and embedded thunderstorms through northern KY and southern IN. This
may be a bit bullish but it would be the last hurrah for the
northern half of the forecast area as the boundary slowly sinks
south (assuming this scenario holds true).
By tomorrow, the focus for convection shifts to the south once again
along the quasi-stationary boundary. As it stands right now, any
storms that fire up during the heat of the day (despite the
continued cloud cover) should wane after sunset Saturday, allowing
for most of the area to remain dry. Under light to calm winds and
lingering low-level moisture, patchy fog could be a factor for not
only tonight (wherever it doesn`t rain) but for tomorrow night as
well. Overnight lows for both nights will range from the upper 60s
to the lower 70s from north to south, respectively. Under the
aforementioned cloud cover, highs tomorrow will again be below
normal, primarily in the mid 80s. Expect this tropical-feeling
airmass to remain in place for the entirety of this forecast period.
.LONG TERM (Sunday night through Friday)...
Issued at 312 PM EDT Fri Aug 9 2013
The start of the long term period will feature generally zonal upper
flow, which will transition to an eastern trough/western ridge by
the end of the long term period. This pattern shift will allow for
drier conditions and cooler/less humid air by the middle of next
week.
A quasi-stationary frontal boundary will be draped from southwest to
northeast across southern Kentucky on Sunday. This will serve as
the focus for showers and thunderstorms to continue, mainly across
southern Kentucky as a shortwave trough rides along the boundary and
brings enhanced vertical motion. As winds turn northerly across
southern Indiana and northern Kentucky due to incoming high
pressure, think enough dry air will work in to actually keep much of
Sunday dry for those regions.
On Sunday night, the surface high will scoot east as another
shortwave trough dives through the Great Lakes region. Guidance
suggests this wave will pull the quasi-stationary front back north
which would give much more of central and northern KY decent
rainfall chances. However, am a bit skeptical of this solution as
the progged system does not appear strong enough to force the front
northward (especially if it`s continually being convectively
reinforced further south). Therefore, the more widespread activity
will likely remain across southern KY, with a general lull in
activity across northern KY and southern Indiana. Given the
continued moist atmosphere south of the front, localized flooding
will need to continue to be watched especially if areas receive
heavy rainfall through the short term period.
By Monday night into Tuesday, another surface front will approach
from the northwest. This front looks much more progressive as the
upper-level flow begins to transition to more northwesterly. As
mentioned in the previous discussion, am a bit skeptical on just how
much moisture will remain ahead of this secondary front, thus will
continue with 30-40 pops as it passes through on Tuesday. Given
the likely moist bias in guidance, instability along this front will
be less than currently progged, thus do not expect severe weather.
However, the drier air working in will help support a few healthy
downdrafts, which may lead to some sub-severe gusts in the
heavier storm cores.
The front will clear the region by Tuesday night, allowing Canadian
high pressure to build into the Ohio Valley. This will bring
welcomed relief from the muggy airmass we have seen of late, as
temperatures fall into the upper 70s/lower 80s with dewpoints in the
50s and lower 60s. This pleasant airmass will also get rid of any
additional storm potential, with dry weather expected Wednesday
through at least the end of next week.
&&
.AVIATION (18Z TAF Update)...
Issued at 128 PM EDT Fri Aug 9 2013
Current radar imagery depicts a line of storms attempting to form
along the stationary boundary draped along the Ohio River. If this
line develops, SDF will be the first to see the impacts this
afternoon and if it is able to hold together, LEX could see some
activity in the area early this evening. With the atmosphere
remaining in its warm, moist, and unstable state, showers and
thunderstorms could pop-up wherever a trigger can be found (i.e. the
frontal boundary). Satellite imagery has shown partial clearing in
southern portions of the commonwealth, particularly around the BWG
terminal. Allowing the sun to peak through will increase daytime
heating in that area, allowing for the potential for thunderstorms
to pop-up in the vicinity. Any afternoon showers and thunderstorms
that develop should wane after sunset as the focus for triggering
then shifts to a mid-level wave traversing through overnight. At
this point, confidence is too low as coverage looks to remain
minimal, if at all overnight. Where confidence is a bit higher is
with respect to the low cloud deck and at least MVFR BR impacts to
all three terminals overnight, especially closer to the pre-dawn
hours. As the front slowly moseys southward, a renewed chance for
convection could impact BWG and potentially LEX but the threat looks
to be south of SDF by tomorrow. Challenging forecast to say the
least as the Ohio Valley remains locked in this tropical-like
pattern through early this weekend.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
Update.........BJS
Short Term.....LG
Long Term......KJD
Aviation.......LG
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
314 PM EDT Fri Aug 9 2013
.SHORT TERM (Now through Saturday Night)...
Issued at 305 PM EDT Fri Aug 9 2013
A line of showers and thunderstorms have begun to form along the
frontal boundary, currently draped along the Ohio River. As has been
the case this week, these are efficient rain producers, dumping a
lot of rain in a short amount of time. Traffic cameras in the
Louisville metro along with obs from SDF confirm the reduced
visibilities accompanying these cells. Thankfully, the line has been
moving relatively quickly off to the east-southeast so unless the
line really fills in, setting up a potential training effect,
flooding shouldn`t be a major concern, especially in north-central
KY where the rain has been much more hit and miss as of late. If it
is able to hold together and makes its way into the Bluegrass
region, there could be some localized problems since FFG is much
lower there due to the recent heavy rains and already saturated
soils. Unfortunately, the models aren`t handling it very well with
the exception of the latest NAM (but its performance this week has
been less than stellar) so its tough to get a solid idea of how this
will play out. While the HRRR doesn`t necessarily depict it well,
this has been one of the top performing models under this regime
and its showing scattered cells developing across much of the center
of the commonwealth. Later tonight, a mid-level wave traverses
through and the HRRR grabs onto it, bringing a cluster of showers
and embedded thunderstorms through northern KY and southern IN. This
may be a bit bullish but it would be the last hurrah for the
northern half of the forecast area as the boundary slowly sinks
south (assuming this scenario holds true).
By tomorrow, the focus for convection shifts to the south once again
along the quasi-stationary boundary. As it stands right now, any
storms that fire up during the heat of the day (despite the
continued cloud cover) should wane after sunset Saturday, allowing
for most of the area to remain dry. Under light to calm winds and
lingering low-level moisture, patchy fog could be a factor for not
only tonight (wherever it doesn`t rain) but for tomorrow night as
well. Overnight lows for both nights will range from the upper 60s
to the lower 70s from north to south, respectively. Under the
aforementioned cloud cover, highs tomorrow will again be below
normal, primarily in the mid 80s. Expect this tropical-feeling
airmass to remain in place for the entirety of this forecast period.
.LONG TERM (Sunday through Friday)...
Issued at 312 PM EDT Fri Aug 9 2013
The start of the long term period will feature generally zonal upper
flow, which will transition to an eastern trough/western ridge by
the end of the long term period. This pattern shift will allow for
drier conditions and cooler/less humid air by the middle of next
week.
A quasi-stationary frontal boundary will be draped from southwest to
northeast across southern Kentucky on Sunday. This will serve as
the focus for showers and thunderstorms to continue, mainly across
southern Kentucky as a shortwave trough rides along the boundary and
brings enhanced vertical motion. As winds turn northerly across
southern Indiana and northern Kentucky due to incoming high
pressure, think enough dry air will work in to actually keep much of
Sunday dry for those regions.
On Sunday night, the surface high will scoot east as another
shortwave trough dives through the Great Lakes region. Guidance
suggests this wave will pull the quasi-stationary front back north
which would give much more of central and northern KY decent
rainfall chances. However, am a bit skeptical of this solution as
the progged system does not appear strong enough to force the front
northward (especially if it`s continually being convectively
reinforced further south). Therefore, the more widespread activity
will likely remain across southern KY, with a general lull in
activity across northern KY and southern Indiana. Given the
continued moist atmosphere south of the front, localized flooding
will need to continue to be watched especially if areas receive
heavy rainfall through the short term period.
By Monday night into Tuesday, another surface front will approach
from the northwest. This front looks much more progressive as the
upper-level flow begins to transition to more northwesterly. As
mentioned in the previous discussion, am a bit skeptical on just how
much moisture will remain ahead of this secondary front, thus will
continue with 30-40 pops as it passes through on Tuesday. Given
the likely moist bias in guidance, instability along this front will
be less than currently progged, thus do not expect severe weather.
However, the drier air working in will help support a few healthy
downdrafts, which may lead to some sub-severe gusts in the
heavier storm cores.
The front will clear the region by Tuesday night, allowing Canadian
high pressure to build into the Ohio Valley. This will bring
welcomed relief from the muggy airmass we have seen of late, as
temperatures fall into the upper 70s/lower 80s with dewpoints in the
50s and lower 60s. This pleasant airmass will also get rid of any
additional storm potential, with dry weather expected Wednesday
through at least the end of next week.
&&
.AVIATION (18Z TAF Update)...
Issued at 128 PM EDT Fri Aug 9 2013
Current radar imagery depicts a line of storms attempting to form
along the stationary boundary draped along the Ohio River. If this
line develops, SDF will be the first to see the impacts this
afternoon and if it is able to hold together, LEX could see some
activity in the area early this evening. With the atmosphere
remaining in its warm, moist, and unstable state, showers and
thunderstorms could pop-up wherever a trigger can be found (i.e. the
frontal boundary). Satellite imagery has shown partial clearing in
southern portions of the commonwealth, particularly around the BWG
terminal. Allowing the sun to peak through will increase daytime
heating in that area, allowing for the potential for thunderstorms
to pop-up in the vicinity. Any afternoon showers and thunderstorms
that develop should wane after sunset as the focus for triggering
then shifts to a mid-level wave traversing through overnight. At
this point, confidence is too low as coverage looks to remain
minimal, if at all overnight. Where confidence is a bit higher is
with respect to the low cloud deck and at least MVFR BR impacts to
all three terminals overnight, especially closer to the pre-dawn
hours. As the front slowly moseys southward, a renewed chance for
convection could impact BWG and potentially LEX but the threat looks
to be south of SDF by tomorrow. Challenging forecast to say the
least as the Ohio Valley remains locked in this tropical-like
pattern through early this weekend.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
Short Term........LG
Long Term.........KJD
Aviation..........LG
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
122 PM EDT FRI AUG 9 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 458 AM EDT FRI AUG 9 2013
WV IMAGERY AND RUC ANALYSIS INDICATED SEVERAL WEAK SHORTWAVES
ROTATING AROUND A MID/UPPER LEVEL LOW OVER NRN ONTARIO. SCT/ISOLD
-SHRA PERSISTED MAINLY ACROSS THE SRN CWA SUPPORTED BY A WEAK
850-700 MB TROUGH AND UPPER LEVEL DIV WITH THE RIGHT ENTRANCE OF A
115 KNOT 300 MB JET TO THE NE OF LAKE SUPERIOR. A SHORTWAVE TROUGH
NW OF LAKE SUPERIOR ALSO SUPPORTED SOME ISOLD/SCT SHOWERS OVER NW
ONTARIO FROM SIOUX LOOKOUT TO DRYDEN.
TODAY...RADAR/SATELLITE TRENDS AND SHORT RANGE MODELS SUGGEST THAT
THE SHOWERS EARLY THIS MORNING WILL DEPART TO THE EAST OF THE CWA BY
AROUND 12Z. ALTHOUGH THE STRONGER 700-500 MB QVECTOR CONV ASSOCIATED
WITH THE NW ONTARIO SHRTWV WILL REMAIN NORTH OF UPPER MICHIGAN...THE
TAIL OF THIS FEATURE COMBINED WITH LOW LEVEL CONV ALONG THE LAKE
SUPERIOR BREEZE BOUNDARY AND MINIMAL MLCAPE VALUES TO NEAR 200 J/KG
IS EXPECTED TO GENERATE ISOLD -SHRA OVER INLAND PORTIONS OF
EAST CNTRL UPPER MICHIGAN. SOME -SHRA MAY ALSO BE POSSIBLE FARTHER
WEST FROM ESC-IMT ALONG A WEAK SFC TROUGH BUT CONFIDENCE WAS LOWER
SO PCPN WAS NOT MENTIONED AT THIS TIME. OTHERWISE...850 MB TEMPS
FROM 7C-9C WILL SUPPORT SCT/BKN CU DEVELOPMENT WITH CONTINUED BELOW
NORMAL HIGHS IN THE UPPER 60S AND LOWER 70S ARE EXPECTED.
TONIGHT...WITH THE LOSS OF DAYTIME HEATING AND HIGH PRES BUILDING
INTO THE REGION...CLEARING SKIES AND DIMINISHING WINDS WILL LEAD TO
FAVORABLE RADIATIONAL COOLING CONDITIONS OVERNIGHT. SO...KEPT FCST
MINS CLOSER TO THE LOWER END OF GUIDANCE...WITH READINGS INTO THE
LOWER TO MID 40S INLAND AND IN THE LOWER 50S ALONG THE GREAT LAKES.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 458 AM EDT FRI AUG 9 2013
OTHER THAN A PERIOD OF SCATTERED SHOWERS AND A FEW THUNDERSTORMS
SUNDAY AFTERNOON INTO MONDAY MORNING...A RATHER EXTENDED PERIOD OF
DRY WEATHER IS EXPECTED WITH SLIGHTLY BELOW NORMAL TEMPERATURES
THROUGH MUCH OF NEXT WEEK.
SATURDAY...DRY AIR WILL CONTINUE TO FILTER IN EARLY IN THE MORNING
AS A REINFORCING SFC HIGH AND WEAK RIDGING MOVE IN FROM THE WEST.
THERE HAS BEEN SOME HINT AT ISOLATED DIURNAL SHOWERS FORMING ACROSS
INTERIOR LOCATIONS BY BOTH THE NAM AND THE GFS OFF AND ON OVER THE
PAST TWO DAYS. INVESTIGATION OF FORECAST SOUNDINGS ACROSS THE CWA
SHOW WIDESPREAD CUMULUS DEVELOPMENT WITH 5 TO 7 KFT DEPTH. GIVEN
SHALLOW CLOUD DEPTH AND INSUFFICIENT MOISTURE ELSEWHERE IN THE
LAYER...ENTRAINMENT OF DRY AIR INTO THE CUMULUS FIELD SHOULD PREVENT
PRECIP DEVELOPMENT. IF ANY SHOWERS WERE TO FORM...THEY WOULD BE VERY
LIGHT AND LIKELY FOCUSED ON LAKE BREEZE CONVERGENCE ZONES ACROSS THE
INTERIOR CENTRAL AND EAST.
SATURDAY NIGHT THROUGH MONDAY NIGHT...WEAK SHORTWAVE RIDGING WILL BE
EXITING TO THE EAST SATURDAY EVENING AS A LARGE TROUGH AXIS ROTATES
SOUTHWARD ON THE BACKSIDE OF A DEEP EASTERN CANADIAN TROUGH. MODELS
HAVE BEEN PICKING UP ON A WEAK LEAD SHORTWAVE TROUGH TRACKING ACROSS
LAKE SUPERIOR SATURDAY NIGHT. DO NOT EXPECT MUCH MORE THAN SOME
INCREASED CLOUDINESS WITH THE WAVE. THE MAIN TROUGH AXIS THEN BEGINS
TO PUSH INTO THE AREA BY SUNDAY MORNING. THE 00Z NAM IS QUITE
AGGRESSIVE WITH BRINGING PRECIP INTO THE WESTERN CWA LATE SATURDAY
NIGHT AS IT APPEARS TO HAVE FALLEN VICTIM TO CONSIDERABLE
CONVECTIVE FEEDBACK FROM A POSSIBLE MCS ACROSS SOUTHERN MN. WILL
THEREFORE IGNORE THIS SOLUTION AND KEEP CONDITIONS DRY SATURDAY
NIGHT.
WITH MANY OF THE MODELS INDICATING DECENT MOISTURE TRANSPORT AND
ISENTROPIC LIFT CONFINED TO SOUTHERN MN AND CENTRAL/SOUTHERN WI...DO
NOT SEE THAT GREAT OF A POTENTIAL FOR ACTIVITY ACROSS THE CWA ON
SUNDAY. THE MAIN WILD CARD FOR THE DAY WILL BE HOW CLOUD DEBRIS FROM
ACTIVITY TO THE SOUTH LIMITS DAYTIME HEATING. WITH OVERALL MOISTURE
PROFILES ABOVE H7 QUITE DRY ACROSS UPPER MI...CLOUD COVER SHOULD
EASILY ERODE AND NOT INHIBIT OPTIMAL HEATING.
FOUND THE 00Z GFS QUITE REASONABLE WITH THE OVERALL SYNOPTIC
SET-UP...SO GAVE IT MORE WEIGHT IN THE FORECAST. A WEAK SECONDARY
SHORTWAVE WILL BE A FOCUS FOR AFTERNOON SHOWER AND STORM DEVELOPMENT
AS THE WAVE REACHES THE CENTRAL CWA BY MID AFTERNOON. WITH NORTHWEST
FLOW ALOFT...0 TO 6 KM BULK SHEAR WILL BE ON THE ORDER OF 35 KNOTS.
HOWEVER...SFC DEW POINTS ONLY IN THE MID 50S WILL LEAD TO POOR
INSTABILITY IN THE FORM OF MLCAPE OF 600 TO 900 J/KG. THIS SHOULD
LIMIT ANY ORGANIZED CONVECTION...AND OVERALL THUNDER COVERAGE FOR
THAT MATTER. HOWEVER...WITH A DRY SUBCLOUD LAYER AND DOWNDRAFT CAPE
OVER 1000 J/KG...THERE IS AN ELEVATED POTENTIAL FOR GUSTY WINDS
UNDER ANY STRONGER SHOWERS/STORMS. BEST CHANCE OF ANY CONVECTION
WILL BE SOUTH CENTRAL AND INTERIOR EAST IN THE AFTERNOON.
EXPECT ANY ACTIVITY TO DIMINISH WITH THE LOSS OF DAYTIME HEATING
SUNDAY EVENING. FORCING IS QUITE CONVOLUTED AT THIS POINT...WITH THE
POTENTIAL FOR MULTIPLE WEAK SHORTWAVES TO TRACK ACROSS THE CWA
THROUGH MONDAY. HAVE OPTED TO KEEP A GENERAL SLIGHT CHANCE OF
SHOWERS IN THE FORECAST FOR SUNDAY NIGHT AND MONDAY GIVEN
UNCERTAINTY OF LOCATIONS FOR BEST FORCING. OVERALL THINKING IS THAT
THE PERIOD WILL BE MOSTLY DRY WITH ONLY SEE ISOLATED SHOWERS FROM
TIME TO TIME.
MONDAY NIGHT THROUGH THURSDAY...MODEL AGREEMENT IS GOOD WITH
BRINGING IN MID-LEVEL RIDGING FROM THE WEST BY MID-WEEK. THERE
IS...HOWEVER...SOME DISAGREEMENT AT HOW QUICK THE TROUGH AXIS
COMPLETELY CLEARS THE CWA. THE GFS HAS SPED UP THE TROUGH OVER
RECENT RUNS...THE ECMWF HAS SLOWED THE TROUGH...AND THE GEM HAS HAS
WEAKENED THE TROUGH. NOT MUCH ONE CAN DO WITH THIS INFORMATION OTHER
THAN STICK WITH CONSENSUS DATA. WITH LIMITED MID-LEVEL
MOISTURE...WILL KEEP PRECIP OUT OF THE FORECAST FOR MONDAY NIGHT AND
TUESDAY. HIGH PRESSURE WILL THEN DOMINATE THE WEATHER THROUGH
THURSDAY. ANOTHER GOOD STRING OF NIGHTS WITH GOOD RADIATIONAL
COOLING APPEAR LIKELY...WITH TUESDAY NIGHT LEADING THE WAY AS THE
SFC HIGH SETTLES OVER THE WESTERN CWA. HAVE THUS LOWERED MIN TEMPS
SEVERAL DEGREES. THE GFS HINTS AT ISOLATED SHOWERS INTERIOR WEST ON
WEDNESDAY AFTERNOON...BUT A STOUT INVERSION WITH LIMITED RETURN
MOISTURE SHOULD PREVENT DEVELOPMENT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 122 PM EDT FRI AUG 9 2013
VFR CONDITIONS ARE EXPECTED AT ALL THREE TAF SITES THIS AFTERNOON.
THERE IS A SLIGHT CHANCE THAT SHOWERS COULD DEVELOP ON THE LAKE
BREEZE THIS AFTERNOON ACROSS EASTERN UPPER MICHIGAN...HOWEVER DO NOT
EXPECT THESE TO IMPACT KSAW. AS A LOW PRESSURE TROUGH CROSSES FROM
ONTARIO INTO QUEBEC THIS AFTERNOON AND EARLY EVENING...THE PRESSURE
GRADIENT BETWEEN THE LOW AND INCOMING HIGH PRESSURE WILL LEAD TO
GUSTY WINDS AT ALL THREE SITES...ESPECIALLY KCMX. EXPECT THESE WINDS
TO DIE DOWN AS THE LOW MOVES FURTHER EAST AND DAYTIME HEATING IS
LOST...SHORTLY AFTER 00Z.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 458 AM EDT FRI AUG 9 2013
WRLY WINDS ARE EXPECTED TO INCREASE INTO THE 15 TO 25 RANGE TODAY
BEHIND A TROUGH MOVING THROUGH LAKE SUPERIOR. HOWEVER...THE STRONGER
WINDS WILL BE RELATIVELY BRIEF SO MAX WAVE HEIGHTS ARE EXPECTED TO
REMAIN MAINLY IN THE 3 TO 5 FOOT RANGE. WINDS WILL VEER NW LATE
TODAY AND DIMINISH TONIGHT TO 5 TO 15 KNOTS AS HIGH PRES BUILDS INTO
THE REGION.
THE COMBINATION OF HIGH PRESSURE TRACKING SOUTHEASTWARD THROUGH WI
AND LOW PRESSURE DROPPING SOUTHWARD FROM NORTHWEST ONTARIO SATURDAY
WILL BRING W TO NW WINDS OF 10 TO 20 KNOTS ACROSS MUCH OF THE LAKE.
THE TROUGH WILL SLOWLY CROSS THE LAKE SUNDAY AFTERNOON THROUGH
MONDAY WITH WINDS UNDER 15 KNOTS. HIGH PRESSURE WILL THEN DOMINATE
THE REGION THROUGH THE MIDDLE OF NEXT WEEK AND PRODUCE WINDS UNDER
15 KNOTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KLUBER
AVIATION...MCD
MARINE...JLB/KLUBER
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
318 PM CDT Fri Aug 9 2013
.SHORT TERM: (Through Late Tonight)
Issued at 317 PM CDT Fri Aug 9 2013
Area of rain extending from central Missouri into southwest Illinois
has persisted on the north side of a side of MCV that is currently
tracking through southeast Missouri. This rain will continue to
show a slow decrease in areal coverage and intensity as the vort
moves off to the east. Focus for additional showers and
thunderstorms this evening will then shift closer to a front over
southern Missouri into southern Illinois. RAP and Local WRF shows
low level forcing persisting along and north of this front most of
the night, so will keep chances of showers and thunderstorms mainly
in areas along and south of I-44 in Missouri and I-64 in
Illinois.
Britt
.LONG TERM: (Saturday through Next Friday)
Issued at 317 PM CDT Fri Aug 9 2013
Primary concern for Saturday through early next week continues to be
timing and intensity of precipitation as quasi-zonal/northwest flow
pattern continues to control our weather. Am continuing the
persistence forecast with high chance/likely pops across the eastern
Ozarks and extreme southwest Illinois, fading to low chance/slight
chance up along the I-70 corridor for Saturday. This morning`s
850mb analysis showed a strong dewpoint gradient along the I-70 with
northerly flow across northern Missouri and moist west-southwest
flow to the south of the gradient. This gradient along with the
northerly flow feeding it is probably at least partially responsible
for the lack of northward progress for today`s precipitation. All
short range guidance keeps the 850mb dewpoint gradient in basically
the same place, hence the persistence forecast. The gradient washes
out on Sunday allowing deeper moisture to filter back into the
region. However, there appears to be a general lack of dynamic
forcing on Sunday with just some weak isentropic lift on 10kt low
level southwest flow. With nothing obvious to focus convection,
will spread chance pops further north, but am not particularly
excited about going with pops higher than chance anywhere at this
time. On Monday, a strong shortwave is forecast to drop down into
the Great Lakes region which should amplify the eastern trof and
push a cold front into the mid Mississippi Valley with a
corresponding increase in pops across the area.
Medium range guidance shows a sprawling high pressure system
building down across the Upper Midwest into the Great Lakes region
late Tuesday into Wednesday. This airmass will be cooler and much
drier than is normal for mid August. 850mb temps on the GFS are
progged to be around 10-12C...which would mix down to the low to mid
70s. The ECMWF is somewhat warmer at 12-14C. Given the
discrepancy...have opted to to stick with ensemble guidance with
highs in the upper 70s to low 80s and lows in the upper 50s to low
to 60s.
Carney
&&
.AVIATION: (For the 18z TAFs through 18z Saturday Afternoon)
Issued at 1248 PM CDT Fri Aug 9 2013
Band of showers with embedded thunderstorms extending from central
MO to just south of the St. Louis metro area will continue to
slowly diminish as it moves east northeast early this afternoon.
Think northern fringe of the rain will be close enough to KSUS and
KCPS to warrant a tempo group with ceilings between 1000-2000feet.
Ceilings this low were recently observed at KUUV and KFYG. There
may still be some scattered thunderstorms redevelop this afternoon
into early this evening.
There may be some fog redevelop late tonight into early Saturday,
particularly in low lying areas. Chances will be lower farther
north where slightly drier air will be working into areas with
less rain.
Specifics for KSTL: Lambert looks like it will be just outside of
northern fringe of area of rain, so have kept with just VCSH at
this point. There may be some redevelopment of showers and
thunderstorms the rest of the afternoon, so have left the VCSH
going until 00Z. Expect rest of forecast period to be dry as
thunderstorms tonight should be well south of Lambert with
clearing skies on Saturday.
Britt
&&
.PRELIMINARY POINT TEMPS/POPS...
Saint Louis 70 86 69 87 / 20 30 10 30
Quincy 64 82 61 85 / 10 10 10 10
Columbia 67 85 65 87 / 20 20 10 20
Jefferson City 67 85 65 87 / 20 30 10 20
Salem 67 83 64 84 / 30 30 10 30
Farmington 66 82 66 84 / 50 60 30 30
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1249 PM CDT Fri Aug 9 2013
.SHORT TERM: (Through Late Tonight)
Issued at 1010 AM CDT Fri Aug 9 2013
Rain chances will increase through late morning as vort max currently
moving into southwest Missouri continues to move northeastward. Band
of showers and thunderstorms currently extending from west of Lake
of the Ozarks to southwest of Farmington is within an area of
decent low level moisture convergence underneath increasing ascent
ahead of the vort max. This forcing will continue primarily over
central and southern Missouri through this evening. Consequently,
I have increased rain chances along and south of I-70 the rest of
the day to account for this. The latest RAP runs show that the low
level moisture convergence will persist over southern Missouri
into the evening close to the front, so may need to up chances in
the southern CWA in later forecasts.
Britt
.LONG TERM: (Tonight through Thursday)
Issued at 312 AM CDT Fri Aug 9 2013
The synoptic pattern over s sections of the FA remains essentially
unchanged tonight through Saturday, as does the seemingly non-stop
threat of showers and thunderstorms over this area. As normal,
models solutions vary in specifics but there does seem to be some
consensus that forcing of low level jet will become focused over
sw MO late tonight and into Saturday morning, although jet is much
weaker than the past few nights. So, expecting yet another
thunderstorm cluster to develop over/advect into SW Missouri
overnight, and work east into S sections of our CWA late tonight
and Saturday morning. At this time not planning any hydro
headlines due to rather weak lift and since s sections of our CWA
have been spared the extreme rains that other parts of southern
Missouri has received; nonetheless, with pwats pushing 2 inches
and given the very effective rain producing capabilities of this
airmass we will certainly be monitoring this threat.
Meanwhile...southward push of surface ridge parked over upper
Mississippi Valley will allow cooler and more stable air to work
into n sections of the CWA later tonight and Saturday. Any storms
that do form in the unstable air over the north this afternoon should
dissipate this evening, with the more stable air limiting
development during the day on Saturday.
Have continued chance POPs over southern sections of the CWA on
Saturday night and Sunday with model consensus indicating some weak
WAA/lift persisting near the weakening baroclinicity.
Eastward progression of surface ridge will allow southerly flow, and
unstable air, to return to northern sections of the CWA by Monday.
This, combined with several shortwaves pushing into area on
persistent NW flow, should mean a threat of thunderstorms for most
of the area Monday and Monday night. However, consensus of medium
range solutions do lower heights over the Great Lakes and the East
Coast as we head into midweek, which should nudge the pesky
baroclinicity a bit more to the south and west, and allow high
pressure to backdoor cooler and more stable air into the region.
Hopefully, this will provide at least temporary respite from the
wet weather in those areas that have been hard hit by flooding
over this past week.
Truett
&&
.AVIATION: (For the 18z TAFs through 18z Saturday Afternoon)
Issued at 1248 PM CDT Fri Aug 9 2013
Band of showers with embedded thunderstorms extending from central
MO to just south of the St. Louis metro area will continue to
slowly diminish as it moves east northeast early this afternoon.
Think northern fringe of the rain will be close enough to KSUS and
KCPS to warrant a tempo group with ceilings between 1000-2000feet.
Ceilings this low were recently observed at KUUV and KFYG. There
may still be some scattered thunderstorms redevelop this afternoon
into early this evening.
There may be some fog redevelop late tonight into early Saturday,
particularly in low lying areas. Chances will be lower farther
north where slightly drier air will be working into areas with
less rain.
Specifics for KSTL: Lambert looks like it will be just outside of
northern fringe of area of rain, so have kept with just VCSH at
this point. There may be some redevelopment of showers and
thunderstorms the rest of the afternoon, so have left the VCSH
going until 00Z. Expect rest of forecast period to be dry as
thunderstorms tonight should be well south of Lambert with
clearing skies on Saturday.
Britt
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS GLASGOW MT
306 PM MDT FRI AUG 9 2013
.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH SUNDAY...
MAIN CONCERN THIS EVENING WILL BE CONVECTIVE POTENTIAL FOR THE
SOUTHERN ZONES. MAINTAINED ISOLATED MENTION...HOWEVER...BEST
INSTABILITY LOOKS TO REMAIN SOUTH OF THE FORECAST REGION. THERE IS
EXCELLENT AGREEMENT ON THIS IDEA FROM THE 12Z/09 MODEL GUIDANCE.
THE GFS IS FURTHER SOUTH BUT THE NAM/ECMWF BRINGS QPF CLOSE ENOUGH
TO THE CWA THAT LEAVING IN ISOLATED SHOWERS/THUNDERSTORMS IS
ACCEPTABLE. THIS HAS FURTHER SUPPORT FROM RECENT HRRR MODEL RUNS
AS WELL. OTHERWISE IT LOOKS LIKE IT WILL BE A QUIET EVENING ACROSS
NORTHEAST MONTANA WITH NORTHWEST FLOW ALOFT DOMINATING AS A RESULT
OF A RIDGE ACROSS THE WESTERN PORTIONS OF THE STATE.
SATURDAY INTO SATURDAY NIGHT...A MOIST UNSTABLE AIR MASS TO THE SOUTH
OF THE CWA WILL GRADUALLY LIFT NORTHWARD. CURRENT ECMWF BRINGS
OVER 1000 J/KG OF CAPE INTO PETROLEUM COUNTY AND SOUTHERN
GARFIELD. PROXIMITY TO THE RIDGE MAY KEEP ENOUGH LARGE SCALE
SUBSIDENCE IN PLACE THAT WIDESPREAD CONVECTION WOULD SEEM
UNLIKELY. GIVEN ABUNDANT CAPE HOWEVER IN THE FAR SOUTHWESTERN
ZONES...ANY STORMS THAT DO DEVELOP WOULD HAVE THE POTENTIAL TO
BECOME STRONG. THERE IS ALSO POOR AGREEMENT WITH THE MODELS AS THE
GFS IS SOMEWHAT MORE BULLISH AND THE NAM/ECMWF SHOWING LESS IN THE
WAY OF QPF...ALTHOUGH CAPE AND SOME OF THE CONVECTIVE PARAMETERS
DO POINT TO SOME OPPORTUNITY. WILL KEEP THE ENTIRE CWA IN A SLIGHT
CHANCE...WITH LOW END CHANCE POPS IN THE SOUTH COINCIDENT WITH THE
HIGHER CAPE/INSTABILITY. GIVEN POTENTIAL DRYING EFFECT FROM
NORTHWEST FLOW ALOFT AND SUBSIDENCE FROM THE RIDGE...CONVECTION
SHOULD BE ISOLATED IN NATURE. HOWEVER...WITH MID LEVEL DRY
AIR...GOOD DIRECTIONAL SHEAR...AND ABUNDANT CAPE...CANNOT RULE OUT
ONE OR TWO SEVERE STORMS IF CONVECTION INITIATION GETS GOING...ESPECIALLY
IN THE FAR SOUTHERN ZONES.
SUNDAY...THE SYNOPTIC PATTERN WILL EXHIBIT VERY LITTLE CHANGE BUT THE
RIDGE AXIS IS EXPECTED TO TRANSLATE FURTHER EAST AND CLOSER TO THE CWA.
THIS SHOULD PROMOTE LARGE SCALE SUBSIDENCE AND SHOULD KEEP CONVECTIVE
POTENTIAL VERY LIMITED. WILL NOT RULE OUT AN ISOLATED SHOWER OR
STORM DUE TO DIURNAL HEATING BUT WITH LACK OF INSTABILITY PRESENT
STORMS SHOULD NOT BECOME STRONG. TEMPERATURES ARE EXPECTED TO
REMAIN SEASONABLY COOL AS COMPARED TO AVERAGES FOR AUGUST...HOWEVER
WITH THE RIDGE BUILDING IN LATER IN THE WEEKEND...RISING HEIGHTS
WOULD FAVOR A SLOW MODERATING TREND. MUCH OF THE CWA WILL RETURN
TO SEEING HIGHS IN THE 80S BY SUNDAY. MALIAWCO
.LONG TERM...SUNDAY NIGHT THROUGH FRIDAY...
MODELS CONTINUE TO ADVERTISE A BIT WITH INCREASED INSTABILITY ABOUT
MIDWEEK. IT MAY BE A BIT EARLY BUT WENT AHEAD AND MADE MENTION OF IT
IN THE HWO. REST OF FORECAST LOOKED GOOD. MODELS ARE BEGINNING TO
SHOW SIGNS OF A STRONGER RIDGE OF HIGH PRESSURE FOR LATE NEXT
WEEK...RESULTING IN TEMPERATURES THAT MAY HIT 90 IN PLACES. TFJ
PREVIOUS DISCUSSION...
THE LONG TERM FORECAST PERIOD IS CHARACTERIZED BY A VERY GRADUAL
BUT CONSISTENTLY STRENGTHENING UPPER LEVEL RIDGE ACROSS THE ROCKY
MOUNTAIN AND HIGH PLAINS REGIONS. THIS WILL SLOWLY PUSH THE LOW
PRESSURE SYSTEM OVER THE PACIFIC NORTHWEST COAST FURTHER NORTH
BEFORE IT JOINS WITH THE LARGER SCALE LOW PRESSURE SYSTEM FROM THE
GULF OF ALASKA BY MID WEEK.
THE SPLIT FLOW OVER THE ROCKY MOUNTAINS QUICKLY REJOINS ON THE LEE
SIDE. THIS IS WHERE THE FORECAST GETS A LITTLE DIFFICULT. BY
THURSDAY OVER MONTANA...THE UPPER LEVEL FLOW SHOWS MORE ZONAL WITH
SOME SUBTLE...UNCERTAIN...AND SMALL SCALE DISTURBANCES TRYING TO
MAKE THEIR WAY THROUGH THE SPLIT FLOW.
MODEL OUTPUTS ALSO INDICATE THE FORECAST COMPLEXITIES WITH THIS BY
CONTINUING TO SHOW DIFFERING SOLUTIONS. GENERALLY SPEAKING...WHERE
THE GFS SHOWS DRY...THE EC SHOWS WET AND VICE VERSA.
GRANTED...LARGE SCALE FORCING FOR ASCENT SHOWS VIRTUALLY NO
ACTIVITY WHAT SO EVER. SO IF ANY PRECIPITATION SYSTEMS MOVE
THROUGH THE REGION...THE IMPACTS ARE EXPECTED TO BE MINIMAL WITH
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS FROM TIME TO TIME.
TEMPERATURES ARE EXPECTED TO GRADUALLY WARM TO NEAR NORMAL LEVELS
FOR THIS TIME OF YEAR. BMICKELSON
&&
.AVIATION...
VFR. GOOD FLYING CONDITIONS THROUGH THE NEXT 24 HOURS. HIGH CLOUDS
FROM THUNDERSTORMS TO OUR SOUTHWEST SHOULD BE ALL THAT MOVES IN
LATER TONIGHT. EAST WINDS WILL REMAIN LIGHT. STORMS LATE SATURDAY
COULD MOVE A BIT CLOSER...BUT NOT ENOUGH TO AFFECT FLIGHT
OPERATIONS. TFJ
&&
.CLIMATE...
SO FAR AUGUST HAS AVERAGED MORE THAN 6 DEGREES BELOW NORMAL IN THE
GLASGOW AREA. THE AVERAGE HIGH TEMPERATURE (AT LEAST FOR GLASGOW)
WILL BEGIN TO DROP SATURDAY WHILE WE SHOULD SEE WARMER CONDITIONS
RETURN NEXT WEEK. TFJ
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS HASTINGS NE
344 PM CDT FRI AUG 9 2013
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 345 PM CDT FRI AUG 9 2013
THE PRIMARY ISSUES DURING THE NEXT 24 HOURS INVOLVES ISOLATED AND
LIKELY NON-SEVERE SHOWER/STORM DEVELOPMENT INTO THIS
EVENING...AND WHETHER OR NOT ANY IMPACTFUL FOG MIGHT DEVELOP AGAIN
OVERNIGHT. HAVE MAINTAINED A SHOWER/STORM-FREE FORECAST CWA-WIDE
FROM LATE THIS EVENING THROUGH SATURDAY AFTERNOON.
20Z OBJECTIVE SURFACE ANALYSIS REVEALS A VERY SUBTLE...WEAK COLD
FRONT ALIGNED GENERALLY EAST-WEST ACROSS THE HEART OF THE NEB
CWA...ALTHOUGH ONE HAS TO LOOK PRETTY TO FIND IT...AS ALL IT
REALLY DOES IS SEPARATE A LIGHT EAST-NORTHEAST BREEZE FROM A LIGHT
EAST TO EAST-SOUTHEAST ONE. THIS LIGHT FLOW WITH SUSTAINED BREEZES
MOST ALL AREAS NO MORE THAN 5-10 MPH IS A RESULT OF BROAD SURFACE
HIGH PRESSURE OVER THE REGION...WITH THE CORE OF THE PARENT HIGH
AROUND 1027 MILLIBARS CENTERED WELL TO THE NORTH OVER
SASKATCHEWAN. ALOFT...WATER VAPOR IMAGERY AND SHORT TERM MODEL
DATA REVEALS RATHER WEAK FLOW ALOFT OVER THE CWA...GENERALLY
WESTERLY UP AT 300MB...NORTHERLY AT 500 MB...AND EVEN FARTHER DOWN
FROM THE EAST-NORTHEAST AT 700MB. ON THE LARGE SCALE...THE CENTRAL
PLAINS LIES IN THE INTERFACE BETWEEN A BROAD TROUGH AND EMBEDDED
VIGOROUS SHORTWAVE TRACKING EAST ACROSS SOUTHEAST CANADA...AND A
RIDGE AXIS EXTENDING EAST-WEST ACROSS THE SOUTHERN CONUS AND THEN
NORTHWARD INTO THE ROCKIES. ON A MORE REGIONAL LEVEL...A LOW-
AMPLITUDE MID LEVEL DISTURBANCE IS LIFTING OUT ACROSS EASTERN
KS/WESTERN MO. OTHER VERY SUBTLE DISTURBANCES APPEAR TO BE
RIPPLING OUT OF THE WY AREA TOWARD WESTERN NEB/SOUTHWEST SD...AND
HELPING TO KICK OFF STORMS IN THE NORTHERN PANHANDLE.
LOCALLY...JUST WITHIN THE PAST HOUR A FEW SMALL...ISOLATED
SHOWERS/POSSIBLY WEAK STORMS HAVE BUBBLED UP OVER DAWSON/BUFFALO
COUNTIES BUT HAVE SHOWED LITTLE SIGN OF MAINTAINING ORGANIZATION.
VISIBLE SATELLITE REVEALS PARTLY TO MOSTLY CLOUDY SKIES OVER THE
CWA AT MID-AFTERNOON...WITH A DECENT LOW LEVEL CUMULUS FIELD
ACROSS MUCH OF THE CENTRAL/WEST...AND SOME LINGERING HIGH CIRRUS
STILL GRADUALLY DEPARTING EASTERN COUNTIES. HIGH TEMPS APPEAR TO
BE FAIRLY WELL ON TRACK...WITH MOST AREAS LIKELY TO END UP IN THE
81-84 RANGE.
GOING FORWARD THROUGH THE LATE AFTERNOON HOURS THROUGH
03Z/10PM...HAVE OPTED TO KEEP THINGS SIMPLE AND ADVERTISE A SLIGHT
CHANCE OF SHOWERS/ISOLATED THUNDERSTORMS CWA-WIDE...ALTHOUGH WOULD
ANTICIPATE THE MOST LIKELY LOCALIZED DEVELOPMENT TO CONTINUE
TARGETING THE WESTERN HALF OF THE NEB CWA...WHERE LATEST MESO-
ANALYSIS INDICATES 0-1KM MLCAPE UP TO AROUND 1500 J/KG...AND WITH
LITTLE IF ANY CINH BUT ALSO VERY LIMITED FORCING FOR ASCENT. WITH
DEEP-LAYER SHEAR AVERAGING NO MORE THAN 15-20KT AND MID LEVEL
LAPSE RATES RATHER SHALLOW AT ONLY 5-6 C/KM...THE THREAT FOR
STRONG TO SEVERE STORMS APPEARS TO BE QUITE LIMITED IF NOT NON-
EXISTENT. POST-03Z/10PM...WILL AIM FOR A DRY REST OF THE
NIGHT...AS ANY DIURNAL SUPPORT FOR CONVECTION FROM AFTERNOON
HEATING WILL BE ON THE WANE...AND GIVEN THAT THE MAIN TRACK OF LOW
AMPLITUDE MID LEVEL DISTURBANCES OVERNIGHT SHOULD GENERALLY TARGET
THE NEB/SD BORDER AREA. FURTHERMORE...THE NOSE OF A MODEST 35KT
850MB LOW LEVEL JET CLEARLY AIMS INTO SOUTHERN SD/FAR NORTH CENTRAL
NEB OVERNIGHT...WHICH IS WHERE MOST MODELS INCLUDING THE NAM AND
4M WRF-NMM FOCUS CONVECTION. THAT BEING SAID...WILL HAVE TO KEEP
AN EYE ON THE NORTHWEST CWA AS THE LATEST HRRR MAINTAINS SOME
SANDHILLS CONVECTION WITHIN 50 MILES OF THE CWA THROUGH AROUND
MIDNIGHT...BUT FEEL THIS MAY BE A BIT CLOSER TO HOME THAN IT
ACTUALLY WILL BE. AT THE SURFACE TONIGHT...BREEZES WILL REMAIN
QUITE LIGHT AND AVERAGE UNDER 5 MPH...WHILE GRADUALLY TURNING TO A
SOUTHERLY DIRECTION. GIVEN THE LIGHT WIND SETUP...THERE IS AT
LEAST SOME CONCERN THAT FOG COULD AGAIN DEVELOP AND REDUCE
VISIBILITY TO 1 MILE OR LESS. HOWEVER...THE CONSENSUS OF
MODELS/GUIDANCE IS THAT TONIGHT/S FOG EVENT SHOULDN/T BE AS
DENSE/IMPACTFUL...POSSIBLY DUE TO SLIGHTLY BETTER BETTER MIXING
JUST ABOVE THE SURFACE. FOR NOW...WILL MAINTAIN THE GENERIC PATCHY
FOG MENTION CWA-WIDE FOR THE LATE NIGHT/EARLY MORNING HOURS
INTRODUCED BY THE PREVIOUS SHIFT...BUT WILL DEFER TO THE NEXT FEW
SHIFTS TO POTENTIALLY RAMP UP THIS FOG WORDING IF NEED BE. AS FOR
LOW TEMPS...ACTUALLY NUDGED DOWN 1-2 DEGREES FROM PREVIOUS IN MOST
SPOTS PER A GUIDANCE BLEND...WHICH PUTS MOST AREAS DOWN BETWEEN
57-61 DEGREES.
TURNING TO THE SATURDAY DAYTIME PERIOD 12Z-00Z/7AM-7PM...MAINTAINED
A RAIN-FREE FORECAST CWA-WIDE. IN THE MID/UPPER LEVELS...FAIRLY
WEAK TO MODEST WEST-NORTHWEST FLOW WILL MAINTAIN OVER THE CENTRAL
PLAINS AT/ABOVE 500MB...AND THERE SHOULD BE SOME SUBTLE HEIGHT
RISES AS WELL...AS THE SOUTHERN PLAINS/SOUTHERN ROCKIES RIDGE
EDGES NORTH JUST A BIT. THE PRIMARY MID LEVEL SHORTWAVE TROUGH
TRACK DURING THE DAY WILL BE FROM SD TOWARD SOUTHWEST MN/NORTHWEST
IA...AND THIS DISTURBANCE SHOULD TEAM WITH AN EAST-WEST QUASI-
STATIONARY FRONT SETTING UP NEAR THE NEB/SD BORDER TO FOCUS THE
VAST MAJORITY OF DAYTIME CONVECTION AT LEAST 50-100 MILES NORTH
AND POSSIBLY NORTHWEST OF THE CWA. THE ODDS OF CONVECTION FORMING
LOCALLY WITH DAYTIME HEATING SEEMS SMALLER THAN TODAY GIVEN
SLIGHTLY WARMER TEMPS EVIDENT AT 700MB...DESPITE MODEST MLCAPE
VALUES CLIMBING INTO THE 500-1000 J/KG RANGE PER THE 18Z NAM.
MODEL FORECASTS SOUNDINGS ALSO CLEARLY SHOW A WEAK BUT EVIDENT CAP.
OTHERWISE...ALTHOUGH BY NO MEANS WINDY...THE LATE MORNING-
AFTERNOON HOURS SHOULD FEATURE SOME OF THE MOST NOTICEABLE MODEST
BREEZES FELT IN MOST OF THE CWA IN SEVERAL DAYS...AS A TIGHTENED
PRESSURE GRADIENT TO THE EAST OF HIGH PLAINS LEE TROUGH SHOULD
PROMOTE SUSTAINED SOUTHERLY SPEEDS 10-15 MPH MOST AREAS. GIVEN THE
SOUTHERLY BREEZES...SLIGHTLY WARMER TEMPS AT 850MB...AND LIKELY NO
WORSE THAN PARTLY CLOUDY SKIES...SEE LITTLE REASON WHY HIGH TEMPS
SHOULDN/T BE AT LEAST A TOUCH HIGHER THAN TODAY. AS A
RESULT...NUDGED UP PREVIOUS HIGHS 1-2 DEGREES IN MOST AREAS...WITH
MOST OF THE CWA AIMED FOR FAIRLY UNIFORM HIGHS BETWEEN 83-86
DEGREES.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 344 PM CDT FRI AUG 9 2013
GUIDANCE SUGGESTS QUASI-ZONAL TO NORTHWESTERLY MID TO UPPER LEVEL
FLOW WILL PERSIST OVER THE CENTRAL PLAINS THROUGH MUCH OF THE LONG
TERM FORECAST PERIOD...WITH THE POSSIBILITY OF MULTIPLE MID LEVEL
PERTURBATIONS MOVING OVER THE AREA. PRECIPITATION CHANCES REMAIN
INTACT THROUGHOUT THE LONG TERM FORECAST PERIOD AS A RESULT.
STARTING SATURDAY NIGHT...THERE ARE SIGNS...PRIMARILY FROM THE
EC...OPERATIONAL GFS AND SREF-MEAN...THAT CENTRAL TO NORTHERN HIGH
PLAINS CONVECTION FROM SATURDAY AFTERNOON/EVENING MAY HOLD TOGETHER
LONG ENOUGH...PRIMARILY DUE TO LOW LEVEL THERMAL ADVECTION ALONG THE
AXIS OF A ~30KT 850MB JET STREAK...TO IMPACT NORTHERN PORTIONS OF
OUR CWA. CONFIDENCE IS NOT OVERLY HIGH THAT MEASURABLE PRECIPITATION
WILL BE REALIZED ACROSS OUR AREA SATURDAY NIGHT AND AS A
RESULT...POPS ONLY IN THE 20-30% RANGE CURRENTLY EXIST. HEADING INTO
THE DAY SUNDAY...LOW LEVEL CONVERGENCE ALONG A LOW LEVEL BAROCLINIC
ZONE/TROUGH COULD PROMOTE ENOUGH LIFT...ALONG WITH A PASSING MID
LEVEL PERTURBATION...TO PROMOTE PRECIPITATION PRODUCTION ACROSS
PORTIONS OF THE REGION. WHERE EXACTLY THE BOUNDARY POSITIONS ITSELF
IS THE BIGGEST QUESTION AT THIS TIME. THE NAM...EC...AND SREF-MEAN
ALL SUGGEST THE BOUNDARY WILL MOVE INTO NORTHERN OR CENTRAL PORTIONS
OF OUR CWA...WHILE THE OPERATIONAL GFS KEEPS THE BOUNDARY TO THE NORTH OF
OUR AREA. GIVEN THE UNCERTAINTY WITH RESPECT TO BOUNDARY
LOCATION...WENT NO HIGHER THAN 20-30% FOR THE DAY SUNDAY. CHANCES
FOR PRECIPITATION...ALBEIT LOW CHANCES DUE TO LOW CONFIDENCE...THEN
CONTINUE ACROSS MUCH OF OUR AREA SUNDAY NIGHT AS THE AXIS OF A
25-30KT 850MB JET STREAK DEVELOPS AND YET ANOTHER MID LEVEL
PERTURBATION POTENTIALLY MOVES OVER PORTIONS OF THE REGION. 20-30%
POPS REMAIN INTACT ACROSS THE AREA SUNDAY NIGHT AS A RESULT.
FINALLY...DURING THE DAY MONDAY...YET ANOTHER WEAK MID LEVEL
PERTURBATION MAY MOVE OVER THE AREA. CONFIDENCE IS LOW WITH RESPECT
TO ANY ONE LOCATION ACROSS THE AREA RECEIVING MEASURABLE
PRECIPITATION BUT RATHER THAN ELIMINATE POPS...WENT AHEAD AND
PRESENTED MOSTLY ~20% POPS TO MUCH OF OUR AREA FOR MONDAY.
MID LEVEL PERTURBATIONS MOVING OVER THE AREA WILL ALSO PROMOTE
CHANCES FOR PRECIPITATION ACROSS OUR AREA MONDAY NIGHT ONWARD AND AS
A RESULT...ALLBLEND PRESENTED POPS RANGING ANYWHERE FROM 20% TO 50%.
AFTER COORDINATION WITH SURROUNDING OFFICES...A FEW MINOR TWEAKS
WERE MADE TO TUESDAY POPS. OTHERWISE...ALLBLEND POPS WERE LEFT
UNCHANGED FOR THE MOST PART DUE TO THE LOW PROBABILITY OF IMPROVING
ON THE ALLBLEND SOLUTION.
DECENT LOW LEVEL MOISTURE...WITH SURFACE DEWPOINTS IN THE UPPER 60S
TO NEAR 70...WILL HELP PROMOTE RESPECTABLE LEVELS OF POTENTIAL
INSTABILITY BOTH SUNDAY AND MONDAY...WITH THE NAM AND OPERATIONAL GFS
BOTH SUGGESTING MUCAPE VALUES IN THE 2500-3500J/KG RANGE. DEEP LAYER
BULK SHEAR DOES NOT APPEAR AS THOUGH IT WILL BE OVERLY
IMPRESSIVE...GENERALLY IN THE 20-25KT RANGE...BUT GIVEN THE EXPECTED
POTENTIAL INSTABILITY WILL GO AHEAD AND OUTLOOK STRONG TO SEVERE
STORMS IN THE HWO FOR SUNDAY AND MONDAY. A SOMEWHAT DRIER LOW LEVEL
AIRMASS IS THEN EXPECTED TO INFILTRATE THE AREA TUESDAY ONWARD THUS
RESULTING IN LOWER POTENTIAL INSTABILITY VALUES. AS A RESULT...WILL
REFRAIN FROM ANY STRONG/SEVERE WEATHER WORDING IN THE HWO TUESDAY
AND BEYOND.
&&
.AVIATION...(FOR THE 18Z KGRI TAF THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1248 PM CDT FRI AUG 9 2013
VFR CEILING/VISIBILITY IS ANTICIPATED FOR THE VAST MAJORITY OF THE
PERIOD...WITH THE MAIN ISSUE BEING ANOTHER POSSIBLE ROUND OF FOG
DURING THE OVERNIGHT/EARLY MORNING HOURS. AT THIS TIME...DENSE FOG
AND ASSOCIATED LIFR/VLIFR CATEGORIES ARE NOT ANTICIPATED...AND
FOR NOW WILL MAINTAIN THEME FROM PREVIOUS FORECAST OF ONLY MVFR
VISIBILITY RESTRICTIONS FROM 08Z-14Z. THIS WILL NEED CLOSELY
WATCHED HOWEVER...AS LIGHT SURFACE WINDS COULD ULTIMATELY FOSTER
WORSE CONDITIONS. OTHERWISE...IN THE NEARER TERM DURING THE NEXT 6
HOURS OR SO...A SCATTERED TO POTENTIALLY BROKEN CUMULUS FIELD
COULD FLIRT WITH HIGH-END MVFR LEVELS...BUT SHOULD PREVAIL NO
WORSE THAN LOWER VFR HEIGHTS. ITS NOT OUT OF THE QUESTION THAT A
ROGUE SHOWER/THUNDERSTORM COULD FLARE UP THIS AFTERNOON INTO EARLY
THIS EVENING...BUT THE LIKELIHOOD/ANTICIPATED COVERAGE DOES NOT
EVEN SEEM TO WARRANT A VCSH/VCTS MENTION AT THIS TIME. SURFACE
WINDS WILL AVERAGE UNDER 10KT THROUGH THE ENTIRE PERIOD...BUT
START TO PICK UP SLIGHTLY FROM THE SOUTH TOWARD THE VERY END OF
THE PERIOD.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...PFANNKUCH
LONG TERM...BRYANT
AVIATION...PFANNKUCH
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1251 PM CDT FRI AUG 9 2013
.UPDATE...
ISSUED AT 1248 PM CDT FRI AUG 9 2013
RECENTLY COMPLETED A FAIRLY MINOR UPDATE. PRECIP-WISE...DELAYED
THE SLIGHT CHANCE OF SHOWERS/ISOLATED THUNDER FOR THE MAJORITY OF
THE CWA UNTIL POST-20Z/3PM. HIGH TEMP- WISE...MADE VERY MINOR 1-2
DEGREE ADJUSTMENTS/MAINLY DOWNWARD/IN MOST NEB ZONES...WITH MORE
OF A 3-5 DEGREE DOWNWARD BUMP IN SOME KS ZONES ESPECIALLY
OSBORNE/MITCHELL COUNTY AREA TO ACCOUNT FOR THICKER HIGH/MID LEVEL
CLOUD COVER. SHALLOW CUMULUS FIELD IS QUICKLY BLOSSOMING IN THE
CLEARING ACROSS MUCH OF THE NORTHWEST 1/4 OF THE CWA...AND TIME
WILL TELL IF THESE ACTUALLY CAN FLARE UP INTO ISOLATED SHOWERS
/NON-SEVERE STORMS.
UPDATE ISSUED AT 1032 AM CDT FRI AUG 9 2013
DENSE FOG ADVISORY WAS ALLOWED TO EXPIRE BY 10 AM AS EXPECTED.
PLENTY OF MID-HIGH CLOUDS CONTINUE TO STREAM NORTH INTO ESPECIALLY
THE CENTRAL/EASTERN CWA FROM A SHORTWAVE TROUGH CENTERED OVER
SOUTHERN/EASTERN KS...AND THIS COULD VERY WELL CONTINUE TO PROMOTE
MOSTLY CLOUDY SKIES WELL INTO THE AFTERNOON HOURS ESPECIALLY EAST
OF HIGHWAY 281...WITH AREAS FARTHER WEST SEEING INCREASING
SUNSHINE. THIS COULD MESS WITH CURRENTLY-ADVERTISED HIGH TEMPS A
BIT AND KEEP SOME PLACES DOWN CLOSER TO 80 VERSUS MID-80S...BUT
WILL STAY THE COURSE FOR NOW AND TAKE ANOTHER LOOK AROUND MID-DAY.
PRECIP-WISE...SLASHED ALL MENTION OF RAIN THROUGH 18Z/1PM EXCEPT
FOR A SLIGHT CHANCE OF SPRINKLES IN OUR FAR SOUTHERN KS ZONES IN
CASE SOMETHING CAN WORK NORTH FROM THE MORE ORGANIZED ACTIVITY IN
CENTRAL KS. FOR THIS AFTERNOON...ODDS ARE PRETTY HIGH THAT THE
VAST MAJORITY OF THE CWA REMAINS DRY...BUT WITH A FAIRLY WEAKLY
CAPPED AIRMASS AND ROUGHLY 500-1000 J/KG 0-1 KM MIXED-LAYER CAPE
PROGGED TO BUILD PER THE LATEST RAP/NAM...HIGHEST IN THE
WEST...HELD ONTO A SLIGHT CHANCE OF SHOWERS/ISOLATED THUNDER THIS
AFTERNOON FOR ALL BUT THE FAR NORTHEASTERN FEW COUNTIES. AS HAS
BEEN THE CASE OF LATE...THIS MODEST CAPE IS DISTRIBUTED IN A
TALL/SKINNY PROFILE WITH MID LEVEL LAPSE RATES ONLY AROUND 6
C/KM...SO THIS SHOULD GREATLY MINIMIZE ANY SEVERE WEATHER
THREAT...ALONG WITH DEEP-LAYER SHEAR ONLY AROUND 20KT OR LESS.
UPDATE ISSUED AT 746 AM CDT FRI AUG 9 2013
THE DENSE FOG ADVISORY HAS BEEN EXPANDED TO INCLUDE SEVERAL MORE
NEBRASKA COUNTIES...BASICALLY EVERYBODY ALONG/SOUTH OF INTERSTATE
80 AND ALSO SHERMAN/HOWARD. AREA AIRPORT OBS AND NDOR WEBCAMS
CLEARLY REVEAL AT LEAST LOCALLY DENSE FOG HAS EXPANDED EASTWARD
INTO THE YORK/AURORA AREAS...AND ALSO AT LEAST INTO NORTHERN
PORTIONS OF COUNTIES BORDERING THE STATE LINE...AS EVIDENCED BY
THE WEB CAM NEAR CAMPBELL. ITS CERTAINLY NOT A SOLID BLANKET OF
DENSE FOG ACROSS THE ENTIRE EXPANDED ADVISORY AREA...BUT ENOUGH
TO JUSTIFY THE HEADLINE FOR THE MORNING COMMUTE. EXPECTING
VISIBILITY TO IMPROVE CONSIDERABLY BY THE 9-10 AM HOUR...AS
SUPPORTED BY THE LATEST HRRR VISIBILITY PROG.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 449 AM CDT FRI AUG 9 2013
MAIN CHALLENGE WILL BE DETERMINING CHANCES OF PRECIPITATION AND
DENSE FOG THIS MORNING. THE LARGE SCALE PATTERN INCLUDES AN UPPER
CLOSED LOW SOUTH OF HUDSON BAY WITH A TROUGH EXTENDING INTO THE
GREAT LAKES AND OHIO VALLEY AND ALSO A CLOSED OVER THE CALIFORNIA
COAST. SOME DENSE FOG HAS DEVELOPED AS A RESULT OF LOW DEWPOINT
DEPRESSIONS AND CALM WIND...PRIMARILY IN THE WEST CENTRAL
CWA...INCLUDING THE TRI- CITIES OF KEARNEY...HASTINGS...AND GRAND
ISLAND. THE FOG SHOULD BURN OFF BY MID-MORNING AS MIXING ENSUES. A
FRONTOLYTIC SURFACE BOUNDARY WILL CONTINUE TO SAG THROUGH THE
VICINITY OF THE CWA TODAY INTO THIS EVENING...WHICH WILL PROVIDE A
FOCUS FOR SOME CONVECTION...ALTHOUGH NOT A HUGE AMOUNT OF SUPPORT.
AS INSTABILITY DECREASES AFTER SUNSET...SO WILL THE SHOT AT SOME
ISOLATED CONVECTION. ALSO...IN THE SOUTHERN CWA...THIS AREA MAY BE
CLOSE ENOUGH TO BE IN A MID- LEVEL FRONTOGENETIC AREA FROM
ACTIVITY IN THE SOUTH TO GET SOME CONVECTION GOING. THERE WILL
PROBABLY NOT BE ENOUGH INSTABILITY FOR THUNDER UNTIL THIS
AFTERNOON AND EVENING...BUT NOT ENOUGH TO SUPPORT SEVERE WEATHER.
STILL GOING WITH HIGHS IN THE 80S WITH THE EXPECTATION OF SOME
SUNSHINE BREAKING OUT AND KEPT SIMILAR TEMPERATURES FROM THE
PREVIOUS FORECAST FOR LOWS TONIGHT. SOME FOG IS NOT OUT OF THE
QUESTION TONIGHT AS WIND WILL BE LIGHT ONCE AGAIN...WITH A SIMILAR
TEMPERATURE AND DEWPOINT SITUATION AS THIS MORNING.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 449 AM CDT FRI AUG 9 2013
MAIN FORECAST CONCERNS WILL BE CHANCES FOR THUNDERSTORMS AND
TEMPERATURES.
NORTHWEST FLOW WILL CONTINUE ACROSS THE AREA THROUGH THE PERIOD WITH
A SERIES OF UPPER LEVEL WAVES THAT MOVE THROUGH THE AREA AND BRING
MULTIPLE CHANCES FOR THUNDERSTORMS. MODELS CONTINUE TO BE SIMILAR IN
THE MAIN FEATURES...BUT THE DETAILS ARE A LITTLE DIFFERENT WITH EACH
MODEL.
SATURDAY WILL CONTINUE TO BE DRY SINCE WE WILL BE BETWEEN UPPER
LEVEL WAVES. THE FIRST WAVE TO MOVE THROUGH WILL MOVE INTO THE AREA
SATURDAY NIGHT. THERE IS A WEAK COLD FRONT ACROSS NORTHERN NEBRASKA
AND AS THE WAVE MOVES INTO THE AREA THUNDERSTORMS ARE EXPECTED TO
DEVELOP ALONG THE FRONT. THIS SHOULD KEEP THE PRECIPITATION CONFINED
TO THE NORTHERN PART OF THE FORECAST AREA.
SUNDAY AND SUNDAY NIGHT THE SURFACE COLD FRONT DRIFTS TO THE SOUTH
AND AS AN UPPER LEVEL WAVE MOVES THROUGH THE CHANCES FOR
THUNDERSTORMS SPREAD ACROSS THE AREA. SUNDAY NIGHT APPEARS AT THIS
TIME TO BE THE BEST CHANCE FOR THUNDERSTORMS ACROSS THE AREA. A FEW
THUNDERSTORMS COULD LINGER INTO MONDAY AS THE FRONT CONTINUES TO
MOVE TO THE SOUTH.
THE NEXT UPPER LEVEL WAVE WILL MOVE INTO THE AREA MONDAY NIGHT AND
TUESDAY. ONCE AGAIN THE BETTER CHANCE FOR THUNDERSTORMS WILL BE
DURING THE NIGHT TIME. THE PERIOD TUESDAY NIGHT THROUGH THURSDAY THE
MODELS HAVE A FEW MORE DIFFERENCES. WILL KEEP SOME MAINLY LOW
CHANCES FOR THUNDERSTORMS ACROSS THE AREA. EXPECT THAT ANY
THUNDERSTORMS WILL BE FAIRLY ISOLATED.
TEMPERATURES FOR SATURDAY AND SUNDAY WILL BE FAIRLY CLOSE TO NORMAL
FOR THIS TIME OF YEAR. WITH THE COLD FRONT MOVING THROUGH SUNDAY THE
TEMPERATURES ON MONDAY WILL BE A LITTLE COOLER. THE SLIGHTLY COOLER
TEMPERATURES WILL CONTINUE THROUGH THURSDAY.
&&
.AVIATION...(FOR THE 18Z KGRI TAF THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1248 PM CDT FRI AUG 9 2013
VFR CEILING/VISIBILITY IS ANTICIPATED FOR THE VAST MAJORITY OF THE
PERIOD...WITH THE MAIN ISSUE BEING ANOTHER POSSIBLE ROUND OF FOG
DURING THE OVERNIGHT/EARLY MORNING HOURS. AT THIS TIME...DENSE FOG
AND ASSOCIATED LIFR/VLIFR CATEGORIES ARE NOT ANTICIPATED...AND
FOR NOW WILL MAINTAIN THEME FROM PREVIOUS FORECAST OF ONLY MVFR
VISIBILITY RESTRICTIONS FROM 08Z-14Z. THIS WILL NEED CLOSELY
WATCHED HOWEVER...AS LIGHT SURFACE WINDS COULD ULTIMATELY FOSTER
WORSE CONDITIONS. OTHERWISE...IN THE NEARER TERM DURING THE NEXT 6
HOURS OR SO...A SCATTERED TO POTENTIALLY BROKEN CUMULUS FIELD
COULD FLIRT WITH HIGH-END MVFR LEVELS...BUT SHOULD PREVAIL NO
WORSE THAN LOWER VFR HEIGHTS. ITS NOT OUT OF THE QUESTION THAT A
ROGUE SHOWER/THUNDERSTORM COULD FLARE UP THIS AFTERNOON INTO EARLY
THIS EVENING...BUT THE LIKELIHOOD/ANTICIPATED COVERAGE DOES NOT
EVEN SEEM TO WARRANT A VCSH/VCTS MENTION AT THIS TIME. SURFACE
WINDS WILL AVERAGE UNDER 10KT THROUGH THE ENTIRE PERIOD...BUT
START TO PICK UP SLIGHTLY FROM THE SOUTH TOWARD THE VERY END OF
THE PERIOD.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...PFANNKUCH
SHORT TERM...HEINLEIN
LONG TERM...JCB
AVIATION...PFANNKUCH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
541 PM CDT FRI AUG 9 2013
.UPDATE...
ISSUED AT 541 PM CDT FRI AUG 9 2013
THE LATEST WATER VAPOR IMAGERY SHOWS NORTHERN/CENTRAL NORTH DAKOTA
DOMINATED BY NORTHWEST FLOW ALOFT...WHILE FAR SOUTHWEST/SOUTHERN
NORTH DAKOTA ARE BECOMING DETACHED FROM THE DOMINATE NORTHWEST FLOW.
HERE...WEAK RIDGING WAS OBSERVED ON WATER VAPOR WHICH EXTENDED FROM
THE FRONT RANGE OF THE ROCKIES INTO THE PANHANDLE OF IDAHO. THIS IS
INDUCING A WEST TO WEAK NORTHWEST FLOW. COUPLE OF SHORTWAVES TO NOTE
FOR TONIGHT/SATURDAY...THE FIRST WAS ALONG THE NORTHERN WYOMING AND
MONTANA BORDER...A SECOND IN CENTRAL IDAHO...AND A THIRD IN EAST
CENTRAL ALBERTA. THESE SHORTWAVES WILL TOP THE RIDGE AND SHIFT EAST
TONIGHT/SATURDAY. THE STRONGEST OMEGA/LIFT FOR TONIGHT AND SATURDAY
REMAINS IN SOUTH DAKOTA...BUT DOES GRAZE WESTERN AND SOUTHERN NORTH
DAKOTA LATER TONIGHT THROUGH SATURDAY. THE LATEST HRRR REFLECTIVITY
SUGGESTS THAT CONVECTION NOW OVER SOUTH CENTRAL MONTANA WILL SHIFT
EAST TONIGHT ALLOWING FOR THE POSSIBILITY OF ISOLATED SHOWERS IN
THE FAR SOUTHWEST AND EDGING FAIRLY CLOSE TO OUR FAR SOUTH CENTRAL
ZONES...MAINLY TOWARD AND AFTER 05Z SATURDAY. WILL CONTINUE TO
WATCH THIS ACTIVITY THIS EVENING. LATEST BOWMAN RADAR IS JUST
BEGINNING TO SHOW SOME WEAK REFLECTIVITY`S IN FAR SOUTHEAST
MONTANA. FOR THIS UPDATE...HAVE INCREASED SKY GRIDS FOR THE EARLY
PART OF THIS EVENING BASED ON VISIBLE SATELLITE AND SURFACE
OBSERVATIONS. REST OF THE FORECAST HAS THE TRENDS HANDLED WELL.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 339 PM CDT FRI AUG 9 2013
THE MAIN FORECAST ISSUE IN THE NEAR TERM IS PRECIPITATION CHANCES
TONIGHT AND SATURDAY. A WARM FRONT WILL LIFT NORTH INTO SOUTH
DAKOTA TONIGHT AS A SHORT WAVE TROUGH TOPS THE UPPER RIDGE. RAIN
COVERAGE IS EXPECTED TO REMAIN RATHER LIMITED ACROSS THE SOUTHERN
COUNTIES SO 20/30 POPS SEEM REASONABLE. SHOWERS AND ISOLATED
STORMS WILL LIKELY PUSH A BIT FARTHER NORTH INTO THE STATE ON
SATURDAY AFTERNOON. THERE SHOULD BE ENOUGH ELEVATED INSTABILITY TO
SUPPORT A FEW THUNDERSTORMS...BUT NO SEVERE WEATHER IS ANTICIPATED.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 339 PM CDT FRI AUG 9 2013
THE EXTENDED WILL BE CHARACTERIZED BY A MID/UPPER LEVEL RIDGE SLOWLY
BUILDING FROM THE ROCKIES EARLY IN THE PERIOD INTO THE CENTRAL
PLAINS BY THE END OF THE PERIOD. THIS WILL GENERATE A GRADUAL
WARMING TREND TO NEAR NORMAL TEMPERATURES BY FRIDAY.
LINGERING CONVECTION ALONG AND SOUTH OF I-94 SATURDAY EVENING SHOULD
WANE WITH THE LOSS OF DAYTIME HEATING.
AS A MID/UPPER RIDGE BUILDS INTO THE REGION...UPPER LEVEL DYNAMICS
WILL BE ON THE DECREASE. HOWEVER...LINGERING MOISTURE AND
INSTABILITY WILL GENERATE A SLIGHT CHANCE OF DIURNALLY DRIVEN
CONVECTION PRIMARILY ALONG AND WEST OF THE MISSOURI RIVER DURING THE
AFTERNOON/EVENING HOURS SUNDAY THROUGH WEDNESDAY.
THE UPPER RIDGE IS PROGGED TO BREAK DOWN SOMEWHAT THURSDAY AS A
RIDGE RUNNER CRESTS OVER THE ANTICYCLONIC RIDGE AXIS. FOR NOW
INDICATED SLIGHT CHANCE POPS AREAWIDE. HOWEVER...POPS MAY NEED TO BE
INCREASED IF FUTURE RUNS ADD CREDENCE TO THE 12Z SUITE OF MODEL
GUIDANCE.
THE RIDGE RUNNER SHORTWAVE IS THEN PROGGED TO PUSH EAST OF THE REGION
FRIDAY WITH PRECIP CHANCES ENDING FROM WEST TO EAST. HIGHS FRIDAY
LOOK TO RANGE FROM THE LOWER 80S EAST TO THE UPPER 80S WEST.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 541 PM CDT FRI AUG 9 2013
KMOT AND KJMS WILL BEGIN WITH LOW VFR CIGS AT 00Z SATURDAY WITH
IMPROVEMENTS TO SCT VFR BY AROUND 03Z. OVERALL SCT/BKN LOW TO MID
LEVEL CLOUDS WILL DOMINATE THROUGH SATURDAY...WITH A VCSH IN
KDIK/KBIS/KJMS UNTIL THE PRECIPITATION AREA BECOMES BETTER APPARENT
FOR PREDOMINANT CONDITIONS. KISN/KMOT LOOK TO BE FAR ENOUGH REMOVED
FROM ANY MENTION OF PRECIPITATION NEXT 24HR.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KS
SHORT TERM...RP KINNEY
LONG TERM...TM
AVIATION...KS
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1230 PM CDT FRI AUG 9 2013
.UPDATE...
ISSUED AT 1230 PM CDT FRI AUG 9 2013
SKY COVER WAS INCREASED A BIT FARTHER SOUTH TO ACCOUNT FOR DIURNAL
CUMULUS DEVELOPMENT. THICKER STRATOCU CLOSER TO THE CANADIAN
BORDER HAS LIMITED THE TEMPERATURE RISE...SO HAVE LOWERED HIGHS BY
A FEW DEGREES FOR THIS AFTERNOON FROM THE DEVILS LAKE BASIN INTO
THE NORTHERN VALLEY. HAVE KEPT THE ISOLATED SHOWER MENTION ALONG
THE CANADIAN BORDER FOR THIS AFTERNOON. THE 16Z RAP SHOWS LITTLE
IN THE WAY OF SHOWER ACTIVITY...BUT STILL SEEING SOME WEAK
UPSTREAM RETURNS.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 354 AM CDT FRI AUG 9 2013
PRIMARY CONCERNS TODAY ARE CLOUD COVER...TEMPERATURES...AND LOW
PRECIPITATION CHANCES. GFS/NAM/ECMWF/GEM ARE IN GOOD AGREEMENT AND
WILL USE A BLENDED SOLUTION FOR THIS FORECAST PACKAGE.
CLOSED 500 HPA LOW ACROSS CENTRAL ONTARIO WILL FINALLY BEGIN TO
PUSH EAST TODAY...ENTERING WESTERN QUEBEC BY 06 UTC TONIGHT.
ANOTHER SHORT-WAVE WILL SWING ACROSS THE FORECAST AREA WITH THE
PRIMARY IMPACT BEING A BAND OF STRATOCU AND LIGHT RAIN SHOWERS.
LATEST 925 TO 850 HPA RH FROM THE RAP SHOWS THESE CLOUDS MOVING AS
FAR SOUTH AS A LINE FROM LANGDON TO GRAND FORKS TO BEMIDJI BEFORE
BEGINNING TO DISSIPATE AND MOVE OUT THE REGION LATER THIS EVENING.
AS A RESULT...INCREASED SKY COVER ACROSS THE NORTHEASTERN THIRD OF
THE FORECAST AREA. ALSO ADDED ISOLATED SHOWER MENTION MAINLY
ACROSS ROSEAU/LAKE OF THE WOODS COUNTIES FROM 15 UTC TO 00 UTC
NOTING RECENT LIGHT RAIN REPORTS AT WINNIPEG AND AREAS UPSTREAM.
AREAS UNDER CLOUD COVER WILL STAY COOL TODAY WITH AFTERNOON HIGHS
MAINLY IN THE MID TO UPPER 60S...PERHAPS REACHING THE LOWER 70S
ALONG THE NORTHERN VALLEY FLOOR. AREAS SOUTH AND WEST WILL SEE
SOME AFTERNOON THERMAL CU GIVEN CONVECTIVE TEMPERATURES IN THE
UPPER 60S TO LOWER 70S...BUT SHOULD SEE ENOUGH SUN FOR HIGHS INTO
THE LOWER TO MID 70S.
SURFACE RIDGE WILL REMAIN ENTRENCHED ACROSS THE REGION OVERNIGHT...
RESULTING IN LIGHT WIND AND SOME DEGREE OF CLEARING ALTHOUGH DO
EXPECT SOME LINGERING CLOUD COVER FROM DEPARTING SHORT-WAVE.
OVERNIGHT LOWS WILL DROP INTO THE UPPER 40S TO NEAR 50 DEGREES.
MODELS HAVE SHIFTED A WARM AIR ADVECTION-INDUCED CONVECTIVE COMPLEX
FRIDAY NIGHT INTO SATURDAY AND SATURDAY NIGHT ALMOST ENTIRELY
SOUTH OF THE ND/SD BORDER. CUT POPS ACROSS ALL BUT THE FAR
SOUTHERN FORECAST AREA AND THIS MAY STILL BE TOO OPTIMISTIC. WILL
KEEP AREAS ACROSS THE NORTH DRY FOR NOW...BUT THERE IS ANOTHER
CANADIAN SHORT-WAVE THAT DROPS ACROSS THE REGION THAT COULD RESULT
IN SOME ISOLATED SHOWERS AWAY FROM THE MAIN CLUSTER ACROSS
SD/SOUTHERN MN. FILTERED SUNSHINE AND LIGHT WINDS SATURDAY WILL
ALLOW TEMPERATURES TO CLIMB INTO THE LOW TO MIDDLE 70S.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 354 AM CDT FRI AUG 9 2013
WITH THE EXCEPTION OF PERHAPS SOME LINGERING LIGHT SHOWERS ACROSS
THE FAR SOUTHEASTERN FORECAST AREA...SUNDAY WILL BE ANOTHER
TRANQUIL DAY WEATHER-WISE AS HIGH PRESSURE CONTINUES ACROSS THE
REGION. ABUNDANT SUNSHINE AND RISING MID-LEVEL THERMAL FIELDS WILL
RESULT IN TEMPERATURES IN THE MID TO UPPER 70S.
MONDAY TO THURSDAY...MODELS IN GOOD AGREEMENT WITH AN OVERALL DRY
PERIOD AS 500MB NW FLOW WITH SFC HIGH PRESSURE DOMINATES THE
WEATHER PATTERN ACROSS THE NORTHERN PLAINS FOR THE FIRST HALF OF
NEXT WEEK. EXPECTED DAYTIME HIGHS TO RISE A DEGREE OR TWO EACH DAY
WITH UPPER 70S ON MONDAY TO LOW 80S...NORMAL FOR MID AUGUST...BY
WEDNESDAY. THERE IS A CHC FOR SOME CONVECTIVE ACTIVITY IN THE AREA
ON WEDNESDAY NIGHT INTO THURSDAY AS A SHORTWAVE SYSTEM IS PROGGED
TO SLIDE OVER THE REGION.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1230 PM CDT FRI AUG 9 2013
AREA OF MVFR TO LOW VFR CIGS CONTINUES TO PUSH SOUTHWARD FROM
MANITOBA BORDER THROUGH THE NORTHERN HALF OF THE FA DOWN TO THE US
HWY 2 CORRIDOR. EXPECT DAYTIME HEATING TO SLOWLY LIFT THIS LOWER
DECK SO THAT BY MID AFTERNOON CIGS SHUD RECOVER ABV VFR THRESHOLD.
SOUTH OF HWY 2 CORRIDOR EXPECT MAINLY VFR CONDS WITH AN INCREASING
VFR CLD DECK IN THE AFTERNOON. NORTHERLY BLAYER WINDS GUSTING FROM
10 TO 20 MPH.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...MAKOWSKI
SHORT TERM...ROGERS
LONG TERM...ROGERS/JK
AVIATION...GUST
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
157 PM CDT FRI AUG 9 2013
.MESOSCALE UPDATE...TO INCLUDE SURFACE BASED CAPES
MESO CONVECTIVE VORTICITY CENTER APPROACHING POPLAR BLUFF AT THIS
TIME. MCV KICKED OFF WHAT APPEARS TO BE A GRAVITY WAVE THAT HAS
JUST CROSSED MISSISSIPPI RIVER. WINDS TURNED WEST AT MEMPHIS WITH
ITS PASSAGE. THIS FEATURE WILL NEED TO BE WATCHED AS IT APPROACHES
THE TENNESSEE RIVER AND MOVES EASTWARD. GRAVITY WAVES CAN IGNITE
STORMS AND INTENSIFY THEM QUICKLY. SURFACE BASED CAPES ARE 4000
PLUS JOULES PER KILOGRAM FROM NORTHEAST MISSISSIPPI NORTHEAST TO
AB OUT NASHVILLE.
BOYD
&&
.PREV DISCUSSION... /ISSUED 154 PM CDT FRI AUG 9 2013/
MESOSCALE UPDATE...
MESO CONVECTIVE VORTICITY CENTER APPROACHING POPLAR BLUFF AT THIS
TIME. MCV KICKED OFF WHAT APPEARS TO BE A GRAVITY WAVE THAT HAS
JUST CROSSED MISSISSIPPI RIVER. WINDS TURNED WEST AT MEMPHIS WITH
ITS PASSAGE. THIS FEATURE WILL NEED TO BE WATCHED AS IT APPROACHES THE
TENNESSEE RIVER AND MOVES EASTWARD. GRAVITY WAVES CAN IGNITE
STORMS AND INTENSIFY THEM QUICKLY.
BOYD
PREV DISCUSSION... /ISSUED 104 PM CDT FRI AUG 9 2013/
UPDATE...
18Z TAF DISCUSSION.
AVIATION...
RADAR IMAGERY SHOWS SCATTERED -SHRA/-TSRA CONTINUE TO AFFECT
CSV...WITH NEW DEVELOPMENT OF -SHRA SOUTH OF CKV/WEST OF BNA.
BASED ON RADAR TRENDS AND LATEST HRRR MODEL RUNS...WILL MENTION
VCTS/VCSH COVERAGE DUE TO SCATTERED NATURE OF CONVECTION WITH MOST
LIKELY PRECIP IMPACTS AT CSV THIS AFTERNOON/EVENING. SCALED BACK
ON PRECIP CHANCES LATE EVENING/TONIGHT BEFORE BRINGING PRECIP
BACK IN TOWARDS SUNRISE. GENERALLY VFR CIGS ANTICIPATED WITH
OCCASIONAL MVFR POSSIBLE...WITH MVFR VIS DUE TO PATCHY FOG AROUND
SUNRISE SATURDAY MORNING AT CKV/CSV. LIGHT SOUTHWEST TO SOUTH
WINDS EXPECTED THROUGH THE TAF PERIOD.
55
PREV DISCUSSION... /ISSUED 1051 AM CDT FRI AUG 9 2013/
UPDATE...
CONVECTION HAS BEEN PRETTY MUCH TIED TO FRONTAL BOUNDARY TO OUR
NORTHWEST BUT WE ARE ALSO BEGINNING TO SEE SCATTERED ACTIVITY
ALONG THE PLATEAU AND SOUTHEAST MIDDLE TENNESSEE. SHOULD SEE
SCATTERED SHOWERS AND STORMS DEVELOP IN THE MID STATE AS WE GO
THROUGH THE DAY AND THINGS HEAT UP. AM EXPECTING MORE NUMEROUS AND
STRONGER ACTIVITY TO OUR NORTH ACROSS SOUTHERN KENTUCKY DURING THE
AFTERNOON THAT WILL WORK ACROSS MY NORTHERN TIER OF COUNTIES IN
THE LATE AFTERNOON. A FEW OF THESE STORMS COULD BE STRONG TO
SEVERE WITH WET MICROBURTS.
FRONTAL BOUNDARY REMAINS DRAPED DOWN ALONG OHIO RIVER INTO EASTERN
OKLAHOMA WITH NOT MUCH IN THE WAY OF PUSH BEHIND IT. WE COULD BE
LOOKING AT ANOTHER ROUND OF LOCALIZED HEAVY RAIN IN HERE TONIGHT
AND SOME OF IT IN SAME AREA THAT GOT COPIOUS AMOUNTS NIGHT BEFORE
LAST. PRECIP EFFICENCY CLIMBS TO > 70 PERCENT NORTH HALF OF MID
STATE TONIGHT WITH MORE RAIN ON SATURDAY. WILL TAKE A CLOSER LOOK
AT THIS SHORTLY.
BOYD
PREV DISCUSSION... /ISSUED 634 AM CDT FRI AUG 9 2013/
UPDATE...FOR 12Z AVIATION DISCUSSION.
AVIATION...12Z AVIATION DISCUSSION.
UNCERTAINTIES...ACTUAL SFC FRONT TIMING MOVEMENT INTO NW PORTIONS OF
MID STATE/ASSOCIATED SHWR/TSTM CHANCES. SFC FRONT TO OUR NW WILL SLOWLY
MOVE INTO NW PORTIONS OF MID STATE BY 10/12Z. WITH MOISTURE RICH ATM IN
PLACE BUT WITH LITTLE INSTABILITY UNTIL 09/16Z-09/18Z...AND SLOW PROGGED
MOVEMENT OF FRONT...HARD TO PINPOINT EXACT SHWR/TSTM LOCATION DEVELOPMENT...
AND WILL MENTION ONLY VCTS REMARKS WITH VFR CEILINGS EXPECTED. AS FRONT
BEGINS TO MOVE INTO MID STATE AFTER 10/00Z...BELIEVE CAT SHWRS/TSTMS WILL
BECOME THE NORM...BUT CEILINGS SHOULD NOT GO BELOW VFR THRESHOLDS.
PREV DISCUSSION... /ISSUED 313 AM CDT FRI AUG 9 2013/
PATTERN THROUGH SUNDAY IS NOT CHANGING THAT MUCH. W-E RIDGE ALOFT
WILL REMAIN ANCHORED ACROSS THE DEEP SOUTH. FRONTAL BOUNDARY WILL
REMAIN TO THE NORTH OF TN. HOWEVER...THIS BOUNDARY WILL MAKE SOME
SOUTHWARD PROGRESS AND LATE FRI NIGHT INTO SATURDAY...SURFACE
CONVERGENCE WILL COUPLE WITH DIVERGENCE ALOFT TO PROVIDE AN
INCREASING CHANCE OF CONVECTION. MOISTURE PARAMETERS PICK UP ON IT
AS WELL WITH THE DEEPEST MOISTURE...BETWEEN NOW AND
SUNDAY...OCCURRING LATE FRI NT AND INTO SATURDAY.
FOR TODAY...LATEST HRRR SHOWING A LULL IN ANY CONVECTION UNTIL
AROUND 19Z OR SO. THE ACTIVITY ACROSS SOUTHERN KY SHOULD LIFT ON OFF
TO THE ENE...BUT WESTERN AND NW AREAS MAY SEE SOME CONVECTION
MOVE IN FROM THE WEST LATER THIS MORNING. HRRR EXPECTS THE
CONVECTION TO WEAKEN THOUGH. OTW...CAP EROSION IS STILL APPARENT
THIS AFTERNOON WITH CAPES ON THE INCREASE. THUS...LOOK FOR SCT
ACTIVITY THIS AFTERNOON. AGAIN...POP CHANCES TO INCREASE LATE
TONIGHT AND ON SATURDAY.
ON SUNDAY...BOUNDARY SHOWS A DECREASE IN FORCING BUT PROXIMITY
INFLUENCES ARE GREATER WITH THE STATIONARY BOUNDARY RIGHT OVER US.
THUS...APPRECIABLE 40-50 POPS WILL CONTINUE.
FOR THE NEAR TERM TEMPS...KEEPING IN MIND THAT THE MAV GUIDANCE HAS
PERFORMED RATHER MISERABLY ON HIGH TEMPS RECENTLY...WILL AGREE TO
BELIEVE IN A CONTINUATION OF THAT FORTUITOUS TREND. WILL UNDERCUT
EACH DAY BY 3 DEG OR SO. WILL GO NEAR TO SLIGHTLY BELOW ON MINS.
IN THE EXT FCST...UPPER TROUGHING PATTERN OVER THE EASTERN U.S. WILL
BEGIN TO EVOLVE. PVA UPSTREAM WILL CATCH UP WITH WEAK SFC BOUNDARIES
AND INTENSIFY A W-E COLD FRONT ALONG THE OHIO RIVER BY MID WEEK.
THIS FEATURE WILL DROP SLOWLY SOUTHWARD WITH A FROPA OCCURRING WED
OR THU. IN ADVANCE OF THE FROPA..CONVECTION CHANCES WILL CONTINUE
WITH THE GREATEST PROBABILITIES OCCURRING TUES AND WED. BEYOND THE
SCOPE OF THE 7 DAY EXT...PERHAPS A DRIER AND SLIGHTLY COOLER AIRMASS
WILL SETTLE IN. 18Z FRI TEMPS FROM A VARIETY OF MODELS ALL SUGGEST A
COOLER TREND...A PRE FALL TASTE OF DRIER PERHAPS? WE WILL SEE.
VERSUS THE EXT TEMPS...850 MB TEMPS AND A SFC 18Z AND 12Z REVIEW ALL
SUGGESTS THAT THE MEX NUMBERS FOR HIGH TEMPS ARE TOO HIGH. WILL
UNDERCUT BY A FEW DEGREES THROUGHOUT THE PERIOD. MINS LOOK GENERALLY
OK.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
01
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
154 PM CDT FRI AUG 9 2013
.MESOSCALE UPDATE...
MESO CONVECTIVE VORTICITY CENTER APPROACHING POPLAR BLUFF AT THIS
TIME. MCV KICKED OFF WHAT APPEARS TO BE A GRAVITY WAVE THAT HAS
JUST CROSSED MISSISSIPPI RIVER. WINDS TURNED WEST AT MEMPHIS WITH
ITS PASSAGE. THIS FEATURE WILL NEED TO BE WATCHED AS IT APPROACHES THE
TENNESSEE RIVER AND MOVES EASTWARD. GRAVITY WAVES CAN IGNITE
STORMS AND INTENSIFY THEM QUICKLY.
BOYD
&&
.PREV DISCUSSION... /ISSUED 104 PM CDT FRI AUG 9 2013/
UPDATE...
18Z TAF DISCUSSION.
AVIATION...
RADAR IMAGERY SHOWS SCATTERED -SHRA/-TSRA CONTINUE TO AFFECT
CSV...WITH NEW DEVELOPMENT OF -SHRA SOUTH OF CKV/WEST OF BNA.
BASED ON RADAR TRENDS AND LATEST HRRR MODEL RUNS...WILL MENTION
VCTS/VCSH COVERAGE DUE TO SCATTERED NATURE OF CONVECTION WITH MOST
LIKELY PRECIP IMPACTS AT CSV THIS AFTERNOON/EVENING. SCALED BACK
ON PRECIP CHANCES LATE EVENING/TONIGHT BEFORE BRINGING PRECIP
BACK IN TOWARDS SUNRISE. GENERALLY VFR CIGS ANTICIPATED WITH
OCCASIONAL MVFR POSSIBLE...WITH MVFR VIS DUE TO PATCHY FOG AROUND
SUNRISE SATURDAY MORNING AT CKV/CSV. LIGHT SOUTHWEST TO SOUTH
WINDS EXPECTED THROUGH THE TAF PERIOD.
55
PREV DISCUSSION... /ISSUED 1051 AM CDT FRI AUG 9 2013/
UPDATE...
CONVECTION HAS BEEN PRETTY MUCH TIED TO FRONTAL BOUNDARY TO OUR
NORTHWEST BUT WE ARE ALSO BEGINNING TO SEE SCATTERED ACTIVITY
ALONG THE PLATEAU AND SOUTHEAST MIDDLE TENNESSEE. SHOULD SEE
SCATTERED SHOWERS AND STORMS DEVELOP IN THE MID STATE AS WE GO
THROUGH THE DAY AND THINGS HEAT UP. AM EXPECTING MORE NUMEROUS AND
STRONGER ACTIVITY TO OUR NORTH ACROSS SOUTHERN KENTUCKY DURING THE
AFTERNOON THAT WILL WORK ACROSS MY NORTHERN TIER OF COUNTIES IN
THE LATE AFTERNOON. A FEW OF THESE STORMS COULD BE STRONG TO
SEVERE WITH WET MICROBURTS.
FRONTAL BOUNDARY REMAINS DRAPED DOWN ALONG OHIO RIVER INTO EASTERN
OKLAHOMA WITH NOT MUCH IN THE WAY OF PUSH BEHIND IT. WE COULD BE
LOOKING AT ANOTHER ROUND OF LOCALIZED HEAVY RAIN IN HERE TONIGHT
AND SOME OF IT IN SAME AREA THAT GOT COPIOUS AMOUNTS NIGHT BEFORE
LAST. PRECIP EFFICENCY CLIMBS TO > 70 PERCENT NORTH HALF OF MID
STATE TONIGHT WITH MORE RAIN ON SATURDAY. WILL TAKE A CLOSER LOOK
AT THIS SHORTLY.
BOYD
PREV DISCUSSION... /ISSUED 634 AM CDT FRI AUG 9 2013/
UPDATE...FOR 12Z AVIATION DISCUSSION.
AVIATION...12Z AVIATION DISCUSSION.
UNCERTAINTIES...ACTUAL SFC FRONT TIMING MOVEMENT INTO NW PORTIONS OF
MID STATE/ASSOCIATED SHWR/TSTM CHANCES. SFC FRONT TO OUR NW WILL SLOWLY
MOVE INTO NW PORTIONS OF MID STATE BY 10/12Z. WITH MOISTURE RICH ATM IN
PLACE BUT WITH LITTLE INSTABILITY UNTIL 09/16Z-09/18Z...AND SLOW PROGGED
MOVEMENT OF FRONT...HARD TO PINPOINT EXACT SHWR/TSTM LOCATION DEVELOPMENT...
AND WILL MENTION ONLY VCTS REMARKS WITH VFR CEILINGS EXPECTED. AS FRONT
BEGINS TO MOVE INTO MID STATE AFTER 10/00Z...BELIEVE CAT SHWRS/TSTMS WILL
BECOME THE NORM...BUT CEILINGS SHOULD NOT GO BELOW VFR THRESHOLDS.
PREV DISCUSSION... /ISSUED 313 AM CDT FRI AUG 9 2013/
PATTERN THROUGH SUNDAY IS NOT CHANGING THAT MUCH. W-E RIDGE ALOFT
WILL REMAIN ANCHORED ACROSS THE DEEP SOUTH. FRONTAL BOUNDARY WILL
REMAIN TO THE NORTH OF TN. HOWEVER...THIS BOUNDARY WILL MAKE SOME
SOUTHWARD PROGRESS AND LATE FRI NIGHT INTO SATURDAY...SURFACE
CONVERGENCE WILL COUPLE WITH DIVERGENCE ALOFT TO PROVIDE AN
INCREASING CHANCE OF CONVECTION. MOISTURE PARAMETERS PICK UP ON IT
AS WELL WITH THE DEEPEST MOISTURE...BETWEEN NOW AND
SUNDAY...OCCURRING LATE FRI NT AND INTO SATURDAY.
FOR TODAY...LATEST HRRR SHOWING A LULL IN ANY CONVECTION UNTIL
AROUND 19Z OR SO. THE ACTIVITY ACROSS SOUTHERN KY SHOULD LIFT ON OFF
TO THE ENE...BUT WESTERN AND NW AREAS MAY SEE SOME CONVECTION
MOVE IN FROM THE WEST LATER THIS MORNING. HRRR EXPECTS THE
CONVECTION TO WEAKEN THOUGH. OTW...CAP EROSION IS STILL APPARENT
THIS AFTERNOON WITH CAPES ON THE INCREASE. THUS...LOOK FOR SCT
ACTIVITY THIS AFTERNOON. AGAIN...POP CHANCES TO INCREASE LATE
TONIGHT AND ON SATURDAY.
ON SUNDAY...BOUNDARY SHOWS A DECREASE IN FORCING BUT PROXIMITY
INFLUENCES ARE GREATER WITH THE STATIONARY BOUNDARY RIGHT OVER US.
THUS...APPRECIABLE 40-50 POPS WILL CONTINUE.
FOR THE NEAR TERM TEMPS...KEEPING IN MIND THAT THE MAV GUIDANCE HAS
PERFORMED RATHER MISERABLY ON HIGH TEMPS RECENTLY...WILL AGREE TO
BELIEVE IN A CONTINUATION OF THAT FORTUITOUS TREND. WILL UNDERCUT
EACH DAY BY 3 DEG OR SO. WILL GO NEAR TO SLIGHTLY BELOW ON MINS.
IN THE EXT FCST...UPPER TROUGHING PATTERN OVER THE EASTERN U.S. WILL
BEGIN TO EVOLVE. PVA UPSTREAM WILL CATCH UP WITH WEAK SFC BOUNDARIES
AND INTENSIFY A W-E COLD FRONT ALONG THE OHIO RIVER BY MID WEEK.
THIS FEATURE WILL DROP SLOWLY SOUTHWARD WITH A FROPA OCCURRING WED
OR THU. IN ADVANCE OF THE FROPA..CONVECTION CHANCES WILL CONTINUE
WITH THE GREATEST PROBABILITIES OCCURRING TUES AND WED. BEYOND THE
SCOPE OF THE 7 DAY EXT...PERHAPS A DRIER AND SLIGHTLY COOLER AIRMASS
WILL SETTLE IN. 18Z FRI TEMPS FROM A VARIETY OF MODELS ALL SUGGEST A
COOLER TREND...A PRE FALL TASTE OF DRIER PERHAPS? WE WILL SEE.
VERSUS THE EXT TEMPS...850 MB TEMPS AND A SFC 18Z AND 12Z REVIEW ALL
SUGGESTS THAT THE MEX NUMBERS FOR HIGH TEMPS ARE TOO HIGH. WILL
UNDERCUT BY A FEW DEGREES THROUGHOUT THE PERIOD. MINS LOOK GENERALLY
OK.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
01
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
104 PM CDT FRI AUG 9 2013
.UPDATE...
18Z TAF DISCUSSION.
&&
.AVIATION...
RADAR IMAGERY SHOWS SCATTERED -SHRA/-TSRA CONTINUE TO AFFECT
CSV...WITH NEW DEVELOPMENT OF -SHRA SOUTH OF CKV/WEST OF BNA.
BASED ON RADAR TRENDS AND LATEST HRRR MODEL RUNS...WILL MENTION
VCTS/VCSH COVERAGE DUE TO SCATTERED NATURE OF CONVECTION WITH MOST
LIKELY PRECIP IMPACTS AT CSV THIS AFTERNOON/EVENING. SCALED BACK
ON PRECIP CHANCES LATE EVENING/TONIGHT BEFORE BRINGING PRECIP
BACK IN TOWARDS SUNRISE. GENERALLY VFR CIGS ANTICIPATED WITH
OCCASIONAL MVFR POSSIBLE...WITH MVFR VIS DUE TO PATCHY FOG AROUND
SUNRISE SATURDAY MORNING AT CKV/CSV. LIGHT SOUTHWEST TO SOUTH
WINDS EXPECTED THROUGH THE TAF PERIOD.
55
&&
.PREV DISCUSSION... /ISSUED 1051 AM CDT FRI AUG 9 2013/
UPDATE...
CONVECTION HAS BEEN PRETTY MUCH TIED TO FRONTAL BOUNDARY TO OUR
NORTHWEST BUT WE ARE ALSO BEGINNING TO SEE SCATTERED ACTIVITY
ALONG THE PLATEAU AND SOUTHEAST MIDDLE TENNESSEE. SHOULD SEE
SCATTERED SHOWERS AND STORMS DEVELOP IN THE MID STATE AS WE GO
THROUGH THE DAY AND THINGS HEAT UP. AM EXPECTING MORE NUMEROUS AND
STRONGER ACTIVITY TO OUR NORTH ACROSS SOUTHERN KENTUCKY DURING THE
AFTERNOON THAT WILL WORK ACROSS MY NORTHERN TIER OF COUNTIES IN
THE LATE AFTERNOON. A FEW OF THESE STORMS COULD BE STRONG TO
SEVERE WITH WET MICROBURTS.
FRONTAL BOUNDARY REMAINS DRAPED DOWN ALONG OHIO RIVER INTO EASTERN
OKLAHOMA WITH NOT MUCH IN THE WAY OF PUSH BEHIND IT. WE COULD BE
LOOKING AT ANOTHER ROUND OF LOCALIZED HEAVY RAIN IN HERE TONIGHT
AND SOME OF IT IN SAME AREA THAT GOT COPIOUS AMOUNTS NIGHT BEFORE
LAST. PRECIP EFFICENCY CLIMBS TO > 70 PERCENT NORTH HALF OF MID
STATE TONIGHT WITH MORE RAIN ON SATURDAY. WILL TAKE A CLOSER LOOK
AT THIS SHORTLY.
BOYD
PREV DISCUSSION... /ISSUED 634 AM CDT FRI AUG 9 2013/
UPDATE...FOR 12Z AVIATION DISCUSSION.
AVIATION...12Z AVIATION DISCUSSION.
UNCERTAINTIES...ACTUAL SFC FRONT TIMING MOVEMENT INTO NW PORTIONS OF
MID STATE/ASSOCIATED SHWR/TSTM CHANCES. SFC FRONT TO OUR NW WILL SLOWLY
MOVE INTO NW PORTIONS OF MID STATE BY 10/12Z. WITH MOISTURE RICH ATM IN
PLACE BUT WITH LITTLE INSTABILITY UNTIL 09/16Z-09/18Z...AND SLOW PROGGED
MOVEMENT OF FRONT...HARD TO PINPOINT EXACT SHWR/TSTM LOCATION DEVELOPMENT...
AND WILL MENTION ONLY VCTS REMARKS WITH VFR CEILINGS EXPECTED. AS FRONT
BEGINS TO MOVE INTO MID STATE AFTER 10/00Z...BELIEVE CAT SHWRS/TSTMS WILL
BECOME THE NORM...BUT CEILINGS SHOULD NOT GO BELOW VFR THRESHOLDS.
PREV DISCUSSION... /ISSUED 313 AM CDT FRI AUG 9 2013/
PATTERN THROUGH SUNDAY IS NOT CHANGING THAT MUCH. W-E RIDGE ALOFT
WILL REMAIN ANCHORED ACROSS THE DEEP SOUTH. FRONTAL BOUNDARY WILL
REMAIN TO THE NORTH OF TN. HOWEVER...THIS BOUNDARY WILL MAKE SOME
SOUTHWARD PROGRESS AND LATE FRI NIGHT INTO SATURDAY...SURFACE
CONVERGENCE WILL COUPLE WITH DIVERGENCE ALOFT TO PROVIDE AN
INCREASING CHANCE OF CONVECTION. MOISTURE PARAMETERS PICK UP ON IT
AS WELL WITH THE DEEPEST MOISTURE...BETWEEN NOW AND
SUNDAY...OCCURRING LATE FRI NT AND INTO SATURDAY.
FOR TODAY...LATEST HRRR SHOWING A LULL IN ANY CONVECTION UNTIL
AROUND 19Z OR SO. THE ACTIVITY ACROSS SOUTHERN KY SHOULD LIFT ON OFF
TO THE ENE...BUT WESTERN AND NW AREAS MAY SEE SOME CONVECTION
MOVE IN FROM THE WEST LATER THIS MORNING. HRRR EXPECTS THE
CONVECTION TO WEAKEN THOUGH. OTW...CAP EROSION IS STILL APPARENT
THIS AFTERNOON WITH CAPES ON THE INCREASE. THUS...LOOK FOR SCT
ACTIVITY THIS AFTERNOON. AGAIN...POP CHANCES TO INCREASE LATE
TONIGHT AND ON SATURDAY.
ON SUNDAY...BOUNDARY SHOWS A DECREASE IN FORCING BUT PROXIMITY
INFLUENCES ARE GREATER WITH THE STATIONARY BOUNDARY RIGHT OVER US.
THUS...APPRECIABLE 40-50 POPS WILL CONTINUE.
FOR THE NEAR TERM TEMPS...KEEPING IN MIND THAT THE MAV GUIDANCE HAS
PERFORMED RATHER MISERABLY ON HIGH TEMPS RECENTLY...WILL AGREE TO
BELIEVE IN A CONTINUATION OF THAT FORTUITOUS TREND. WILL UNDERCUT
EACH DAY BY 3 DEG OR SO. WILL GO NEAR TO SLIGHTLY BELOW ON MINS.
IN THE EXT FCST...UPPER TROUGHING PATTERN OVER THE EASTERN U.S. WILL
BEGIN TO EVOLVE. PVA UPSTREAM WILL CATCH UP WITH WEAK SFC BOUNDARIES
AND INTENSIFY A W-E COLD FRONT ALONG THE OHIO RIVER BY MID WEEK.
THIS FEATURE WILL DROP SLOWLY SOUTHWARD WITH A FROPA OCCURRING WED
OR THU. IN ADVANCE OF THE FROPA..CONVECTION CHANCES WILL CONTINUE
WITH THE GREATEST PROBABILITIES OCCURRING TUES AND WED. BEYOND THE
SCOPE OF THE 7 DAY EXT...PERHAPS A DRIER AND SLIGHTLY COOLER AIRMASS
WILL SETTLE IN. 18Z FRI TEMPS FROM A VARIETY OF MODELS ALL SUGGEST A
COOLER TREND...A PRE FALL TASTE OF DRIER PERHAPS? WE WILL SEE.
VERSUS THE EXT TEMPS...850 MB TEMPS AND A SFC 18Z AND 12Z REVIEW ALL
SUGGESTS THAT THE MEX NUMBERS FOR HIGH TEMPS ARE TOO HIGH. WILL
UNDERCUT BY A FEW DEGREES THROUGHOUT THE PERIOD. MINS LOOK GENERALLY
OK.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
307 PM CDT FRI AUG 9 2013
.SHORT TERM...
.Tonight and Saturday...
Isolated severe thunderstorms with damaging winds possible again
this afternoon and evening. The best potential will be in the Big
Country, along a weak cold front along the I-20 corridor.
Discussion:
Conditions are similar to yesterday with an inverted V sounding.
Instability was fairly high. RAP ML CAPES ranged from 2000-3000 J/KG
in the Big Country and Concho Valley, with the highest values near
Sweetwater. Focus for initial storm development will be a weak front
along the I-20 corridor...although a few storms will likely develop
farther south along thunderstorm outflow boundaries. Main
thunderstorm threat will be damaging winds. With weak steering
currents, storm movement will be slow. This may also bring
localized flooding in urban areas.
The front is expected to move south Saturday afternoon...becoming
stationary somewhere along the I-10 corridor...although placement is
uncertain. The main threat will be strong gusty winds and dangerous
lightning.
.LONG TERM...
.Saturday Night...
Slight chance of storms will linger into the evening hours.
Whatever is left of the weak cold front will remain somewhere across
West Central Texas, along with whatever outflow boundaries may still
be in the area. Any storms that develop during the heat of the day
will keep going until shortly after sunset before dissipating.
.Sunday into Wednesday...
A dry pattern will prevail, with temperatures not quite as hot.
Upper level ridge of high pressure takes a bigger role for early
next week, slowly shifting back to the west. Low level temperatures
and 850 mb readings are forecasted to be cooler by a few degrees, so
forecast highs at or hopefully just below the 100 degree mark. With
the ridge in place overhead and without a boundary to aid, getting
any thunderstorms to develop will be extremely tough. Will opt to
keep the forecast dry.
.Wednesday Night into Friday...
Storms will be possible again across the Big Country.
By late Wednesday, the upper level ridge will have shifted far
enough to the west to put West Central Texas into northwest flow.
This is typically a wetter pattern, as storms develop across the
Panhandle during the afternoon and move southeast into the area
during the overnight hours. Best chances look to be across the Big
Country and Heartland with the chances decreasing to the southwest.
Have inserted pops for the northeast portions of the area for now,
and leave the remainder of the area dry. But if the northwest flow
sets up as the models suggest, may have to expand the rainfall
coverage as we get into next week.
Otherwise, northwest flow is usually a little cooler as well. This
is shown in the model guidance, showing highs near climatology
normals in the mid to upper 90s.
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 100 71 96 76 96 / 20 30 20 20 10
SAN ANGELO 103 71 99 74 97 / 20 30 20 20 10
JUNCTION 103 72 100 75 97 / 10 5 20 20 10
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
04/07
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
115 PM EDT FRI AUG 9 2013
.SYNOPSIS...
A SLOW MOVING COLD FRONT IS EXPECTED TO APPROACH THE REGION FROM
THE NORTHWEST THIS EVENING BEFORE PASSING SOUTHEAST THROUGH OUR
AREA THIS WEEKEND. HIGH PRESSURE OVER THE UPPER MIDWEST SHIFTS
SOUTHEAST THROUGH THE MID ATLANTIC BY THE END OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 935 AM EDT FRIDAY...
FOG/STRATUS FADING WITH BETTER HEATING UNDER LESS CLOUD COVER
THIS MORNING AND EXPECT MOST TO CLEAR IN THE NEXT HOUR OR SO. OTRW
FRONT REMAINS STALLED OUT ACROSS THE SRN OHIO VALLEY THIS MORNING
PRECEDED BY A BAND OF SHRA/TSRA ASSOCIATED WITH WEAK S/W ENERGY
ALONG THE RESIDUAL PRE-FRONTAL ZONE. MORNING SOUNDINGS SHOW BETTER
FLOW ALOFT AHEAD OF THE FRONT/WAVE THIS MORNING WITH DECENT
WESTERLY FLOW WHICH SHOULD HELP SHRA/TSRA MOVE A BIT FASTER THIS
AFTERNOON. HOWEVER UNIDIRECTIONAL TRAJECTORY MAY OFFSET THIS BY
ALLOWING STORMS TO ALIGN IN BANDS ESPCLY AS THE SFC-85H STEERING
BRIEFLY TURNS MORE SW WITH THE PASSING VORT NOW OVER KY AROUND MID
AFTERNOON. THIS SHOULD HELP PROMPT DEVELOPMENT ALONG THE SRN BLUE
RIDGE AS SEEN VIA SEVERAL SOLNS WITH ANOTHER AREA ACROSS THE FAR
NW WITH THE SAGGING CONVECTION TO THE NW. LATEST MODIFIED RAOBS
ALSO SHOW MUCH MORE CAPE/INSTABILITY PER MORE INSOLATION THIS
AFTERNOON ESPCLY BLUE RIDGE EAST WHERE STRONGER STORMS APPEAR
LIKELY PER BETTER JET ALOFT. STILL APPEARS THREAT FOR FLOODING
RAINFALL WILL BE MORE LOCALIZED UNLESS BLUE RIDGE CONVECTION AND
COVERAGE TO THE NW COMES TOGETHER SO STILL HOLDING OFF ON ANY
WATCHES FOR NOW.
OTRW HAVE ADJUSTED POPS FOR SLOWER ARRIVAL NW GIVEN CURRENT RADAR
TRENDS AND INCREASED TO LIKELYS IN A BAND BLUE RIDGE VICINITY
WHERE 2-3K J/KG CAPES POSSIBLE. WEST WIND ALONG WITH COMPRESSION
AHEAD OF THE FRONT SHOULD COMBO WITH HEATING AND +19-20C AT 85H TO
PUSH HIGHS TO ARND 90 SE AND MAINLY 80S ELSW PER OBSERVED
THICKNESS.
PREVIOUS DISCUSSION AS OF 330 AM EDT FRIDAY...
RADARS QUIET THIS MORNING WITH ONLY ONE LONE SHOWER EXITING NRN
GREENBRIER COUNTY WITH MOST CONVECTION CENTERED WITH AND AHEAD OF A
SHORTWAVE AROUND CINCINNATI. THE 12Z ECMWF/00Z GFS ZERO IN ON THIS
SHORTWAVE AND PRECIP AND MAINLY SEE IT SHIFTING ENE INTO NRN WV
LATER THIS MORNING WITH A FEW SHOWERS MAKING ITS WAY INTO SE WV. FOR
EARLY TODAY WILL BE DEALING WITH AREAS OF FOG...LOCALLY DENSE AS IT
HAS CLEARED OUT SOME ASIDE FROM SOME HIGH CLOUDS. THIS FOG WILL BE
GOING AWAY AROUND 900 AM.
LOOKING AT WSW FLOW BACKING DURING THE DAY AND AFTER MIDDAY MODELS
SHOWING SOME LOW LVL CONVERGENCE ALONG THE BLUE RIDGE WITH A
PREFRONTAL TROUGH...WITH UPPER SUPPORT AND MAIN FRONT STAYING ACROSS
THE OHIO VALLEY INTO THE MID ATLANTIC. THINK COVERAGE WILL AGAIN
BECOME SCATTERED TO NUMEROUS OVER THE MOUNTAINS THEN SHIFT TO THE
PIEDMONT AS FLOW BACKS. WITH BETTER MIXING AND MORE SUNSHINE...THE
INSTABILITY AND CONVECTIVE TEMPS SUPPORT MORE THUNDER. STORMS WILL
BE HEAVY RAIN PRODUCERS AND MEAN FLOW SHOWING STORM MOVEMENT OF 10
TO 20 MPH. OVERALL THREAT FOR SVR THUNDERSTORMS AND FLASH FLOODING
REMAINS ISOLATED...SO NO WATCHES FOR FLASH FLOODING EXPECTED AND
WILL CONTINUE TO MENTION HEAVY RAIN...ISOLATED SVR IN THE HWO.
AS WE HEAD INTO LATE AFTERNOON AND EARLY EVENING THE LOW LVL FLOW
VEERS TO THE WEST AND THE GFS ESPECIALLY DRIES THE LEE SIDE OF THE
MOUNTAINS OUT WHILE HOLDING ONTO CONVECTION IN THE PIEDMONT...SO
WILL BE LEANING TOWARD LOWER POPS IN THE NEW RIVER VALLEY/FOOTHILLS
BY DUSK WHILE KEEPING THE WRN SLOPES AND PIEDMONT WITH HIGHER POPS.
OUR LOCAL WRF AND HRRR SHOWING THIS TO BE THE CASE AS WELL.
THINK WILL SEE SHOWERS AND STORMS SUBSIDE AGAIN BY LATE
EVENING/MIDNIGHT ESPECIALLY IN THE EAST WITH LOSS OF HEATING BUT
EXPECT THE THREAT OF SHOWERS TO REMAIN OVER THE WV/FAR SW VA MTNS
AHEAD OF THE FRONT AND CLOSER TO THE UPPER LEVEL SUPPORT.
FOR HIGHS TODAY WENT CLOSE TO THE ECMWF MOS AS THE GFS SEEMS TO WARM
AND NAM TOO COOL. LOOKING AT WARMER TEMPS WITH MORE SUN AND MIXING
BEFORE STORMS SET IN...WITH LOWER 80S WEST TO MID 80S TO NEAR 90
EAST.
TONIGHT REMAINS MUGGY WITH LOWS GENERALLY IN THE MID TO UPPER 60S
MOUNTAINS INTO THE LOWER 70S EAST.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY NIGHT/...
AS OF 400 AM EDT FRIDAY...
SHOWERS AND THUNDERSTORMS WILL REMAIN IN THE FORECAST THIS WEEKEND
INTO THE NEXT WORKWEEK AS A COLD FRONT MAKES ITS WAY ACROSS OUR
REGION. IN STICKING CLOSE WITH THE ECMWF MODEL SOLUTION...EXPECT TO
START SATURDAY OFF WITH THE COLD FRONT SITUATED NEAR THE INTERSTATE
81 CORRIDOR...WITH THE FRONT DRIFTING SLOWLY SOUTHWARD THROUGH THE
DAY...PERHAPS AIDED IN ITS PUSH BY OUTFLOW FROM AFTERNOON/EVENING
SHOWERS AND THUNDERSTORMS. BY SUNDAY MORNING...THE FRONT IS EXPECTED
TO ADVANCE INTO NORTH CAROLINA...WHERE IT WILL STALL AND BEGIN TO
WASH OUT ON MONDAY AS ANOTHER COLD FRONT APPROACHES FROM THE UPPER
MIDWEST.
DESPITE THE PASSAGE OF THE FRONT...WILL STILL SEE ABUNDANT LOW LEVEL
MOISTURE ACROSS OUR AREA AS DRIER AIR LINGERS TO OUR NORTH. MINOR
DISTURBANCES ALOFT WILL CONTINUALLY PASS ALONG THE FRONT FROM THE
WEST DURING THE WEEKEND...AND WILL TRIGGER ROUNDS OF SHOWERS AND
THUNDERSTORMS...MAINLY EACH AFTERNOON AND EVENING WHEN ENHANCED BY
DAYTIME HEATING. AS IN PREVIOUS NIGHTS...BELIEVE WE WILL SEE A
DRASTIC REDUCTION IN THE AMOUNT OF SHOWER ACTIVITY AFTER
SUNSET...ALTHOUGH CANNOT RULE A FEW SHOWERS DURING THE OVERNIGHTS.
WILL ALSO POINT OUT THE POSSIBILITY OF A FEW STRONG STORMS ON
SATURDAY AND SUNDAY...MORE SO SOUTH OF INTERSTATE 81. WHILE STRONG
THUNDERSTORM WINDS AND FREQUENT LIGHTNING WILL BE CONCERNS...THE
GREATEST CONCERN WILL BE FROM LOCALLY HEAVY RAIN AND THE POSSIBILITY
OF FLASH FLOODING. ANY FLOODING SHOULD REMAIN LOCAL IN SCALE...BUT
MAY DEVELOP QUICKLY IN STORMS WITH HIGH RAINFALL RATES...AND
ESPECIALLY IN LOCATIONS WITH SATURATED SOILS FROM RECENT HEAVY RAIN.
&&
.LONG TERM /TUESDAY THROUGH THURSDAY/...
AS OF 350 PM EDT THURSDAY...
A COLD FRONT ASSOCIATED WITH AN IMPRESSIVE CHUNK OF CHILLY AIR FOR
THIS TIME OF YEAR WILL ALLOW SHOWERS AND STORMS TO CROP UP AGAIN ON
TUESDAY. ONCE THIS BOUNDARY PASSES...H85 TEMPS MAY FALL AS COLD AS
+9C BY THE MIDDLE OF NEXT WEEK. THE CHILLY AIR ALOFT WILL PRODUCE
EXTENSIVE CLOUDS AND PROBABLY WIDELY SCATTERED SHOWERS. BY THE END
OF NEXT WEEK...THIS FRONT BEGINS TO JOG NORTH AGAIN AND WARMER AIR
RETURNS.
&&
.AVIATION /17Z FRIDAY THROUGH TUESDAY/...
AS OF 100 PM EDT FRIDAY...
OVERALL FLAVOR OF THE FORECAST WILL BE CONVECTION ALONG AND WEST
OF THE BLUE RIDGE THROUGH EARLY AFTERNOON...WITH THE FOCUS
SHIFTING TO THE PIEDMONT LATER THIS AFTERNOON...THEN FOG/STRATUS
FOR BLUE RIDGE WESTWARD OVERNIGHT. HAVE LOW CONFIDENCE IN VFR
CIGS/VSBYS OVERNIGHT...ESPECIALLY IF THESE AIRPORTS SEE ANY
SIGNIFICANT DIRECT PRECIPITATION TODAY. HOWEVER...FEEL THE
GENERAL WIND DIRECTION GOING TO WLY WILL LEAD TO SOME DOWNSLOPE
AND HELP MITIGATE NOCTURNAL FOG AND LOW CIGS. WILL GO AGAINST MOS
GUIDANCE HERE AND RATHER THAN HEDGE...WILL GO WITH AN OPTIMISTIC
FORECAST FOR KDAN AND KLYH.
MODELS SEEM TO HAVE A DECENT HANDLE ON PCPN TRENDS AND CONTINUE
TO SQUEEZE OUT SOME LIGHT SHOWERS FOR THE OVERNIGHT ALONG AND WEST
OF THE BLUE RIDGE IN LIGHT W/NWLY FLOW. WILL BRING IN THE LOW
CLOUDS AND FOG AT KBLF/KLWB/KBCB AND USE VCSH TO HANDLE THE PCPN
AT KBLF/KLWB. KROA WILL BE IN THE TRANSITION ZONE BUT WILL SHADE
THINGS TO THE OPTIMISTIC SIDE AND USE A TEMPO FOR SOME MVFR
CIGS/VSBY.
...AVIATION EXTENDED...
THE FRONT SHIFTS SLOWLY SOUTHEAST THRU THE WEEKEND AND KEEPS THE
THREAT OF SHOWERS/STORMS AROUND. THE FRONT MAY SLIP SOUTH OF THE
AREA BY MONDAY INTO TUESDAY WITH STILL SOME THREAT OF SHOWERS OVER
THE SRN CWA FROM DAN-BCB-BLF.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...WP
NEAR TERM...JH/WP
SHORT TERM...NF
LONG TERM...KM
AVIATION...MBS/WP
AREA FORECAST DISCUSSION
NWS SPOKANE WA
1123 AM PDT Fri Aug 9 2013
.SYNOPSIS...
QUIET WEATHER THIS MORNING WILL BE FOLLOWED BY INCREASED CLOUDS
AND A THREAT OF PRECIPITATION THIS AFTERNOON. FROM THIS EVENING
THROUGH MUCH OF NEXT WEEK A PERSISTENT WEATHER PATTERN WILL BRING
A CHANCE OF THUNDERSTORMS EACH DAY WITH TEMPERATURES REMAINING
SEASONABLY WARM.
&&
.DISCUSSION...
This afternoon...The east-west band of elevated convection...which
crossed the WA/ID border earlier this morning continues to drift
slowly northward...away from parent upper low. Cloud tops have
generally warmed over the past couple hours and suspect that trend
will continue as it usually does with elevated convection this
time of day. The threat of elevated convection will wane through
early-afternoon...however if the HRRR model solution is
correct...the threat will perk up by mid-afternoon. RUC forecasts
show the greatest CAPEs this afternoon developing over the central
Idaho Panhandle and the dying band of elevated convection could
be the driving trigger. Although CAPEs rise across the entire
forecast area this afternoon...there will be a decent amount of
convective capping or CIN to overcome and given the positioning of
the upper level low this may not be accomplished. Pops have been
lowered for most locations aside from the central Panhandle and
along the Cascades. Remainder of forecast left generally as
is...but decreased cloud cover a bit. Afternoon temps still look
warm for this time of year with highs generally in the 90s. fx
&&
.AVIATION...
18Z TAFS: VFR conditions expected at all sites through the period.
Only weather of consequence was band of elevated instability and a
few Accas clouds near KPUW...KLWS...and KMWH moving slowly
northward. Cloud tops will likely be too low to produce
lightning...but there is a remote chance. Looks like thunder
chances will increase this afternoon but most should keep clear of
TAF sites. Biggest threat will occur over the central ID
Panhandle. The threat will increase again late this evening or
overnight as a weak shortwave approaches from the south.
Confidence is low that any will directly hit any forecast
site...however it was at least worth a mention of VCTS between
06-12z or so. fx
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 93 66 91 65 88 64 / 10 20 20 50 50 40
Coeur d`Alene 91 61 90 60 88 58 / 10 20 20 50 50 40
Pullman 92 56 89 55 87 52 / 20 30 20 40 40 30
Lewiston 99 66 96 65 94 64 / 20 30 20 40 40 30
Colville 96 57 93 57 92 56 / 10 20 20 50 50 40
Sandpoint 89 57 88 55 86 54 / 10 20 30 40 50 50
Kellogg 89 59 88 58 86 57 / 20 30 20 60 60 50
Moses Lake 97 65 95 64 93 61 / 10 30 40 50 30 20
Wenatchee 96 70 94 69 93 67 / 10 30 60 60 50 40
Omak 98 66 96 64 95 62 / 10 30 40 50 70 40
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...WA... Red Flag Warning from 5 PM this afternoon to 11 PM PDT Sunday
for East Washington Central Cascade Mountains (Zone 682)-
East Washington Central Cascade Valleys (Zone 677)-East
Washington North Cascades (Zone 685)-East Washington
Northern Columbia Basin (Zone 673)-East Washington
Okanogan/Methow Valleys (Zone 684)-East Washington Palouse
and Spokane Area (Zone 674)-East Washington South Central
Cascade Mountains (Zone 680)-East Washington South Central
Cascade Valleys (Zone 676).
Flash Flood Watch from Saturday morning through Sunday evening
for East Slopes Northern Cascades-Waterville Plateau-
Wenatchee Area.
&&
$$