Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 09/12/15
AREA FORECAST DISCUSSION
NWS TAUNTON MA
702 PM EDT THU SEP 10 2015
.SYNOPSIS...
A FRONT WILL PUSH NORTH OVERNIGHT AND PROVIDE A FOCUS FOR LOCALLY
HEAVY DOWNPOURS OVERNIGHT. LOW PRESSURE FROM THE MID-ATLANTIC WILL
MOVE NORTHEAST ALONG THE FRONT PAST OUR AREA FRIDAY MORNING PULLING
IT OUT TO SEA FOLLOWED BY WEAK HIGH PRESSURE THAT BRINGS A LULL IN
THE WEATHER SATURDAY. WET-WEATHER RETURNS FOR SUNDAY BUT NOT A WASH-
OUT. TURNING DRY AND WARMER INTO NEXT WEEK. POSSIBLE RECORD BREAKING
HEAT INTO MID- TO LATE-SEPTEMBER AS ABOVE-AVERAGE TEMPS ARE FORECAST.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
7 PM UPDATE...
TWO AREAS OF FOCUS. THE FIRST IS ACROSS THE INTERIOR. INDICATIONS
OF MID-LEVEL FRONTOGENESIS WILL BE ONGOING DURING THE OVERNIGHT
HOURS. CAN SEE SOMEWHAT OF A BANDING SIGNATURE WITHIN THE BROADER
RADAR LOOP MOVING INTO NEW ENGLAND FROM THE MID- TO UPPER-HUDSON
VALLEY REGION OF NY. A FOCUS OF HIGHER PWAT OF NEARLY 2-INCHES AND
THERE IS STILL THE LIKELIHOOD OF HEAVY RAIN ACROSS INTERIOR AREAS
OF S NEW ENGLAND TO WARRANT THE FLASH FLOOD WATCH. FEEL THERE WILL
BE A SQUEEZE...BUT DISPLACED FROM THE MORE FAVORABLE REGIONS OF
THE RIGHT-REAR-QUADRANT OF THE UPPER-LEVEL-JET TO THE N...MAY NOT
SEE SIGNIFICANT DEEP-LAYER LIFT. FOCUSED ACTIVITY LOOKS TO BE THE
RESULT OF CONVERGENCE POTENTIALLY SUPPORTED BY VENTING ALOFT IN
ADDITION TO FALLING HEIGHTS.
SECOND AREA OF FOCUS IS OVER SE NEW ENGLAND. HIGHER THETA-E AIR
AND ACCOMPANYING INSTABILITY AXIS. THIS IS WHERE LIKELY THUNDER
WILL PROCEED DURING THE OVERNIGHT HOURS WITHIN THE ANTICYCLONIC
BRANCH OF THE WARM-MOIST CONVEYOR BELT AS SYNOPTICALLY THIS IS AN
OPEN-WAVE SYSTEM. NO REASON TO BELIEVE THIS WILL CURTAIL BACK
CYCLONICALLY TOWARDS THE INTERIOR. PARENT WITH A H925-85 LOW-
LEVEL-JET AND AREAS OF CONVERGENCE...THE HEAVIEST RAIN AND THE
STRONGEST OF ACTIVITY LOOKS TO OCCUR HERE. MAY HAVE TO EXTEND THE
FLASH FLOOD WATCH FOR SE NEW ENGLAND INTO THE MORNING HOURS. WILL
LET THE OVERNIGHT CREW EVALUATE AND DECIDE TOWARDS THE EXPIRATION.
OVERALL...A WELCOMING RAINFALL AS MUCH OF THE AREA HAS BEEN DRY
SINCE MID-AUGUST. D0-D1 ABNORMAL TO MODERATE DROUGHT CONDITIONS
HAVE BEEN FLAGGED ACROSS THE REGION. THIS BENEFICIAL RAIN SHOULD
EASE SUCH DRY CONDITIONS AND BRING RESERVOIRS AND STREAMFLOWS BACK
UP TO NEAR-NORMAL LEVELS.
WILL KEEP IT MILD OVERNIGHT WITH THE LIKELIHOOD OF PATCHY FOG
AND/OR LOW VISIBILITIES WITH ANY HEAVY RAIN ESPECIALLY ACROSS THE
S/SE-COAST WITH HIGHER DEWPOINT AIR IN THE UPPER-60S TO LOW-70S.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
COASTAL LOW PRESSURE MOVES OFF TO THE EAST FRIDAY MORNING...CARRYING
ANY REMAINING PCPN OFF TO THE EAST. MODEL MOISTURE FIELDS SHOW
DRYING FROM WEST TO EAST DURING THE DAY...SUGGESTING A CLEARING
TREND FRIDAY AFTERNOON INTO FRIDAY NIGHT.
MEANWHILE...A LARGER UPPER SHORTWAVE DIGS OVER THE GREAT LAKES AND
MAINTAINS A SOUTHWEST FLOW ALOFT. THE SUPPORTING UPPER JET WILL BE
POSITIONED OVER THE EASTERN GREAT LAKES...GENERATING MORE CONVECTION
IN THAT AREA WHILE NEW ENGLAND HAS WEAK SUBSIDENCE. SO FRIDAY
AFTERNOON AND NIGHT SHOULD BE A DRY PERIOD. NORTH WIND FRIDAY WILL
DIMINISH FRIDAY NIGHT INLAND.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
*/ HIGHLIGHTS...
- KEEPING IT DRY ON SATURDAY
- WET WEATHER FOR SUNDAY BUT NOT LOOKING LIKE A WASHOUT EVERYWHERE
- HEAVY RAIN THOUGH MAY IMPACT SE NEW ENGLAND ... HIGH TERRAIN
- DRY AND WARM INTO NEXT WEEK ... POSSIBLE RECORD BREAKING HEAT
*/ DISCUSSION...
KEEPING WITH AN ENSEMBLE APPROACH. H5 DEEP-TROUGH CLOSED LOW SWEEPS
THROUGH THE OHIO-RIVER VALLEY SATURDAY AHEAD OF WHICH THERE IS RIDGE-
AMPLIFICATION KEEPING US MOSTLY DRY WITH LIKELY SOME MID-HIGH LEVEL
CLOUDS ACROSS THE REGION. LIFTING E SUNDAY DIFFLUENCE PROCEEDS ABOVE
LOW-MID LEVEL LIFT / CONVERGENCE BUT CONVINCED S NEW ENGLAND IS IN
AN AREA OF LESS FAVORABLE DEVELOPMENT. TWO AREAS OF INTEREST: THE
CYCLONIC TROWALING ROUND THE CLOSED LOW BACK INTO THE E GREAT LAKES
WHERE DEFORMATION PROCEEDS...AND SE NEW ENGLAND AND POINTS OFFSHORE
WITHIN THE ANTI-CYCLONIC BRANCH OF THE WARM CONVEYOR BELT WHERE HIGH
THETA-E VALUES RESIDE BENEATH DIFFLUENCE AND ENHANCED ASCENT WITH
CONVERGENCE ALONG A STRONG H925-7 JET. S NEW ENGLAND BELOW THE RIGHT-
FRONT-QUADRANT OF THE UPPER-LEVEL-JET AND IN THE CROSS-HAIRS OF A
MID-LEVEL DRY-PUNCH WRAPPING INTO THE OCCLUDING SYSTEM PER ENSEMBLE
MEANS LOOKS TO RESULT IN LITTLE OUTCOME OVER THE AREA. IN OTHER
WORDS...NOT APPEARING TO BE A WASHOUT ON SUNDAY. CAN NOT RULE OUT
HIGHER AMOUNTS OVER THE HIGHER TERRAIN.
WITH ENSEMBLES LIFTING THE TROWAL N OF THE REGION SUNDAY NIGHT INTO
MONDAY...LESS CONFIDENCE OF OUTCOMES ON MONDAY BENEATH THE COLD POOL
AS THE TROUGH MAY MOVE THRU PRIOR TO BOUNDARY-LAYER DESTABILIZATION.
PERHAPS SOME ACTIVITY UP AGAINST THE W-SLOPES OF HIGHER TERRAIN N OF
OUR AREA WITH W-WIND CONVERGENCE.
FOR THE REMAINDER OF THE WEEK...CONSISTENT SIGNALS OF RIDGING. THINK
HEAT AND HUMIDITY BUILD BACK INTO THE REGION. AGREE WITH THE CLIMATE
PREDICTION CENTER WITH ABOVE-AVERAGE TEMPERATURES. ENSEMBLES SIGNAL
ANOMALOUS H85 TEMPERATURES ACROSS THE REGION. THINKING THAT WE COULD
BREAK SOME RECORD HIGH TEMPERATURES INTO MID- TO LATE-SEPTEMBER.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH FRIDAY NIGHT/...
TONIGHT...MODERATE CONFIDENCE.
CONFIDENT MVFR-VLIFR MIX WITH CIGS. LOWER CONFIDENCE WITH VSBYS
BUT EXPECT IFR WITH RA/+RA. FOG ALONG WITH LIFR-VLIFR CIGS LIKELY
AN ISSUE FOR S/SE-COASTAL TERMINALS ALONG WITH A GREATER PROPENSITY
OF FOG. WILL LEAN HIGHER TSRA CHANCES TOWARDS THE S/SE-COASTAL
TERMINALS PREVAILING WITH VCTS. E/NE-WINDS BACKING OUT OF THE N
TOWARDS MORNING.
FRIDAY...MODERATE CONFIDENCE.
IMPROVEMENT BEGINNING DURING THE MORNING TOWARDS VFR. NE-WINDS
INCREASING AND GUSTING TO 20 KTS ALONG THE COASTS.
FRIDAY NIGHT...HIGH CONFIDENCE.
EXPECT MVFR-LIFR FOG DEVELOPMENT ESPECIALLY OVER THE INTERIOR
TOWARDS MORNING. TYPICALLY PRONE TERMINALS WITHIN SHELTERED
VALLEYS LIKELY TO EXPERIENCE LIGHT WINDS OVERNIGHT LIKE THE CT-
RIVER VALLEY ESPECIALLY PRONE.
KBOS TERMINAL...MODERATE CONFIDENCE IN TAF. WILL KEEP THUNDER OUT
OF THE TAF OVERNIGHT EXPECTING IT TO REMAIN E/SE OFFSHORE.
KBDL TERMINAL...MODERATE CONFIDENCE IN TAF.
OUTLOOK /SATURDAY THROUGH TUESDAY/...
SATURDAY...HIGH CONFIDENCE.
VFR. WINDS VEERING E/SE. A MAINLY DRY FORECAST.
SATURDAY NIGHT - SUNDAY NIGHT...MODERATE CONFIDENCE.
MVFR-IFR MIX WITH E/SE-ONSHORE FLOW BACKING SW TOWARDS THE END OF
THE FORECAST PERIOD. RAIN LIKELY ACROSS THE REGION. PATCHY FOG
POSSIBLE. MAY ALSO CONTEND WITH SOME LLWS IMPACTS.
MONDAY INTO TUESDAY...MODERATE CONFIDENCE.
VFR. W/SW-WINDS WITH GUSTS UP TO 20 KTS.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH FRIDAY NIGHT/...HIGH CONFIDENCE IN TRENDS.
MODERATE CONFIDENCE IN SPECIFIC TIMING.
7 PM UPDATE...NO MAJOR CHANGES.
TONIGHT...INCREASING COVERAGE IN SHOWERS AND THUNDERSTORMS.
LOCALLY HEAVY DOWNPOURS POSSIBLE. AREAS OF POOR VISIBILITY IN FOG
ESPECIALLY AROUND NANTUCKET
FRIDAY...LOW PRESSURE LIFTING NE ACROSS THE WATERS. SHOWERS AND
AREAS OF FOG START THE DAY. INCREASING NORTH WINDS WILL REACH 20
KNOTS ON OUR EASTERN WATERS AND COULD GET AS STRONG AS 25 KT. THE
N-NE FETCH SHOULD BE ENOUGH TO BUILD SEAS ON THE EXPOSED EASTERN
WATERS TO 5 FEET...POSSIBLY 6. A SMALL CRAFT ADVISORY HAS BEEN
POSTED ON THE OUTER WATERS AND IN MASS BAY...PRIMARILY FOR SEAS
BUT WITH AN EYE TOWARD THE WINDS AS WELL.
FRIDAY NIGHT...MODERATE CONFIDENCE.
DIMINISHING NORTH TO NORTHWEST WINDS WITH SEAS SUBSIDING AFTER
MIDNIGHT.
OUTLOOK /SATURDAY THROUGH TUESDAY/...
SATURDAY...MODERATE CONFIDENCE.
A LULL IN THE WEATHER. WINDS BECOME LIGHT WHILE VEERING E/SE. SHOULD
SEE SEAS SUBSIDE FOR THE PERIOD BELOW 5-FEET.
SUNDAY...MODERATE CONFIDENCE.
DEEPER AREA OF LOW PRESSURE TO THE W. WILL SEE AN ACCOMPANYING WARM
FRONT LIFT N ACROSS THE WATERS BRINGING WITH IT RAIN ALONG WITH
INCREASING E/SE-ONSHORE WINDS. GUSTS UP TO 20 KTS. WAVE HEIGHTS
BUILDING IN EXCESS OF 5-FEET INITIALLY OVER THE S WATERS EXPANDING
TO THE E/SE WATERS LATE IN THE PERIOD.
MONDAY...MODERATE CONFIDENCE.
IMPROVING. WINDS BACK OUT OF THE W/SW AND REMAIN ROBUST WITH A
STRONG AREA OF LOW PRESSURE SITUATED WELL TO THE W ACROSS THE
INTERIOR. ANOTHER DAY OF GUSTS UP TO 20 KTS WHILE SEAS REMAIN AT OR
IN EXCESS OF 5-FEET ON THE WATERS.
&&
.HYDROLOGY...
7 PM UPDATE...
RAINFALL RATES TODAY HAVE BEEN EFFICIENT AT TIMES WITH 2 TO 4
INCHES PER HOUR. FEEL THIS RISK PERSISTS THROUGH THE OVERNIGHT
ESPECIALLY THOSE AREAS OF HIGHER THETA-E WHICH ARE FORECAST TO
PREVAIL OVER SE NEW ENGLAND. NEVERTHELESS...CONVERGENCE ALONG A
FRONTAL BOUNDARY OVER THE INTERIOR OF A 2-INCH PWAT AIRMASS IS
LIKELY TO LEAD TO LOCALIZE EFFICIENCY OF HEAVY RAIN. NOT ABSOLUTELY
CERTAIN ON THE SPECIFICS AS TO WHERE...BUT A SW-NE BAND IS EXPECTED
ACROSS THE INTERIOR WARRANTING THE CONTINUATION OF THE FLASH FLOOD
WATCH.
WITH SE NEW ENGLAND UNDER THE FAVORABLE ENVIRONMENT OF HIGHER
THETA-E AIR ACCOMPANIED WITH INSTABILITY AND A LOW-LEVEL-JET AND
AREAS OF LOCALIZED CONVERGENCE...THE PROPENSITY FOR HEAVY RAIN
ALONG WITH THUNDERSTORMS IS GREATER. MAY NEED TO EXPAND THE FLASH
FLOOD WATCH FOR SE NEW ENGLAND PAST MIDNIGHT INTO THE MORNING
HOURS. WILL ALLOW THE OVERNIGHT SHIFT TO RE-EVALUATE AND AMEND AS
NECESSARY.
EFFICIENT HEAVY RAINFALL PRODUCERS AS WE HAVE SEEN EARLIER TODAY
LEAD TO FLASH FLOODING...ESPECIALLY MORE SO NOW FOR AREAS THAT
HAVE ALREADY BECOME WELL-SATURATED FOR THE DAY. SUBSEQUENTLY THIS
EMPHASIZES THE NECESSARY CONTINUATION OF THE FLASH FLOOD WATCH.
SEE THE UPDATED DISCUSSION AT THE TOP OF THE AFD FOR FURTHER DETAILS.
NEAR-TERM HIGH-RES GUIDANCE SUCH AS THE HRRR AND RAP WERE UTILIZED
IN MAKING THE DETERMINATIONS TO THE FORECAST OVER THE NEXT 12 HOURS.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...FLASH FLOOD WATCH UNTIL 6 AM EDT FRIDAY FOR CTZ002>004.
MA...FLASH FLOOD WATCH UNTIL MIDNIGHT EDT TONIGHT FOR MAZ017>022.
FLASH FLOOD WATCH UNTIL 6 AM EDT FRIDAY FOR MAZ002>016-026.
RI...FLASH FLOOD WATCH UNTIL MIDNIGHT EDT TONIGHT FOR RIZ002>007.
FLASH FLOOD WATCH UNTIL 6 AM EDT FRIDAY FOR RIZ001.
MARINE...SMALL CRAFT ADVISORY FROM 2 AM FRIDAY TO 6 AM EDT SATURDAY FOR
ANZ250-254.
SMALL CRAFT ADVISORY FROM 5 AM TO 4 PM EDT FRIDAY FOR ANZ251.
SMALL CRAFT ADVISORY FROM 2 PM FRIDAY TO 2 AM EDT SATURDAY FOR
ANZ255-256.
&&
$$
SYNOPSIS...WTB/SIPPRELL
NEAR TERM...WTB
SHORT TERM...WTB
LONG TERM...SIPPRELL
AVIATION...WTB/SIPPRELL
MARINE...WTB/SIPPRELL
HYDROLOGY...SIPPRELL/FRANK/WTB
AREA FORECAST DISCUSSION
NWS TAUNTON MA
353 PM EDT THU SEP 10 2015
.SYNOPSIS...
A FRONT STALLED ALONG THE SOUTHERN NEW ENGLAND SOUTH COAST WILL
PUSH NORTH OVERNIGHT AND PROVIDE A FOCUS FOR LOCALLY HEAVY
DOWNPOURS DURING THE NIGHT. LOW PRESSURE FROM THE MID ATLANTIC
STATES WILL MOVE NORTHEAST PAST OUR AREA FRIDAY MORNING. WEAK
HIGH PRESSURE THEN BRINGS A LULL IN THE WEATHER SATURDAY. WET-
WEATHER RETURNS FOR SUNDAY BUT NOT APPEARING TO BE A WASHOUT.
PERHAPS SOME HEAVY RAIN FOR THE HIGH TERRAIN AND SOUTHEAST NEW
ENGLAND. TURNING DRY AND WARMER INTO NEXT WEEK. COULD BE LOOKING
AT THE POSSIBILITY OF RECORD BREAKING HEAT INTO MID- TO LATE-
SEPTEMBER AS ABOVE-AVERAGE TEMPS ARE FORECAST.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
A COLD FRONT LIES NORTH OF NANTUCKET BUT SOUTH OF THE REMAINDER OF
NEW ENGLAND AND LONG ISLAND. SOUTHWEST FLOW ALOFT HAS A FAINT
SHORTWAVE MOVING THROUGH WITH LOW LEVEL FLOW DRAWING VERY MOST AIR
NORTH OVER THE TOP OF THE FRONT. PRECIPITABLE WATER VALUES
CONTINUE EITHER SIDE OF 2 INCHES...WHICH IS ABOUT AS HIGH AS IT
GETS IN SOUTHERN NEW ENGLAND IN SEPTEMBER.
THE SURFACE FRONT SUPPORTS LOW LEVEL CONVERGENCE AND THE UPPER
SHORTWAVE SUPPORTS UPPER VENTING...AND THIS WILL BE WORKING ON A
VERY JUICY AIRMASS. WE WILL CONTINUE WITH CATEGORICAL POPS FOR
SHOWERS/SCATTERED TSTMS THIS EVENING AND TONIGHT. BASED ON THE
HIGH PW AIR...WE CONTINUE TO EXPECT LOCALLY HEAVY DOWNPOURS THAT
WILL BRING LOCALLY HEAVY DOWNPOURS. BEST CHANCE WILL BE WITH THE
BEST LIFT ALONG AND NORTH OF THE FRONT.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
COASTAL LOW PRESSURE MOVES OFF TO THE EAST FRIDAY
MORNING...CARRYING ANY REMAINING PCPN OFF TO THE EAST. MODEL
MOISTURE FIELDS SHOW DRYING FROM WEST TO EAST DURING THE
DAY...SUGGESTING A CLEARING TREND FRIDAY AFTERNOON INTO FRIDAY
NIGHT.
MEANWHILE...A LARGER UPPER SHORTWAVE DIGS OVER THE GREAT LAKES AND
MAINTAINS A SOUTHWEST FLOW ALOFT. THE SUPPORTING UPPER JET WILL BE
POSITIONED OVER THE EASTERN GREAT LAKES...GENERATING MORE CONVECTION
IN THAT AREA WHILE NEW ENGLAND HAS WEAK SUBSIDENCE. SO FRIDAY
AFTERNOON AND NIGHT SHOULD BE A DRY PERIOD. NORTH WIND FRIDAY WILL
DIMINISH FRIDAY NIGHT INLAND.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
*/ HIGHLIGHTS...
- KEEPING IT DRY ON SATURDAY
- WET WEATHER FOR SUNDAY BUT NOT LOOKING LIKE A WASHOUT EVERYWHERE
- HEAVY RAIN THOUGH MAY IMPACT SE NEW ENGLAND ... HIGH TERRAIN
- DRY AND WARM INTO NEXT WEEK ... POSSIBLE RECORD BREAKING HEAT
*/ DISCUSSION...
KEEPING WITH AN ENSEMBLE APPROACH. H5 DEEP-TROUGH CLOSED LOW SWEEPS
THROUGH THE OHIO-RIVER VALLEY SATURDAY AHEAD OF WHICH THERE IS RIDGE-
AMPLIFICATION KEEPING US MOSTLY DRY WITH LIKELY SOME MID-HIGH LEVEL
CLOUDS ACROSS THE REGION. LIFTING E SUNDAY DIFFLUENCE PROCEEDS ABOVE
LOW-MID LEVEL LIFT / CONVERGENCE BUT CONVINCED S NEW ENGLAND IS IN
AN AREA OF LESS FAVORABLE DEVELOPMENT. TWO AREAS OF INTEREST: THE
CYCLONIC TROWALING ROUND THE CLOSED LOW BACK INTO THE E GREAT LAKES
WHERE DEFORMATION PROCEEDS...AND SE NEW ENGLAND AND POINTS OFFSHORE
WITHIN THE ANTI-CYCLONIC BRANCH OF THE WARM CONVEYOR BELT WHERE HIGH
THETA-E VALUES RESIDE BENEATH DIFFLUENCE AND ENHANCED ASCENT WITH
CONVERGENCE ALONG A STRONG H925-7 JET. S NEW ENGLAND BELOW THE RIGHT-
FRONT-QUADRANT OF THE UPPER-LEVEL-JET AND IN THE CROSS-HAIRS OF A
MID-LEVEL DRY-PUNCH WRAPPING INTO THE OCCLUDING SYSTEM PER ENSEMBLE
MEANS LOOKS TO RESULT IN LITTLE OUTCOME OVER THE AREA. IN OTHER
WORDS...NOT APPEARING TO BE A WASHOUT ON SUNDAY. CAN NOT RULE OUT
HIGHER AMOUNTS OVER THE HIGHER TERRAIN.
WITH ENSEMBLES LIFTING THE TROWAL N OF THE REGION SUNDAY NIGHT INTO
MONDAY...LESS CONFIDENCE OF OUTCOMES ON MONDAY BENEATH THE COLD POOL
AS THE TROUGH MAY MOVE THRU PRIOR TO BOUNDARY-LAYER DESTABILIZATION.
PERHAPS SOME ACTIVITY UP AGAINST THE W-SLOPES OF HIGHER TERRAIN N OF
OUR AREA WITH W-WIND CONVERGENCE.
FOR THE REMAINDER OF THE WEEK...CONSISTENT SIGNALS OF RIDGING. THINK
HEAT AND HUMIDITY BUILD BACK INTO THE REGION. AGREE WITH THE CLIMATE
PREDICTION CENTER WITH ABOVE-AVERAGE TEMPERATURES. ENSEMBLES SIGNAL
ANOMALOUS H85 TEMPERATURES ACROSS THE REGION. THINKING THAT WE COULD
BREAK SOME RECORD HIGH TEMPERATURES INTO MID- TO LATE-SEPTEMBER.
&&
.AVIATION /20Z THURSDAY THROUGH TUESDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH FRIDAY NIGHT/...
TONIGHT...MODERATE CONFIDENCE. IFR AND SOME LIFR CIGS/VSBYS IN
SHOWERS/TSTMS WITH HEAVY DOWNPOURS. NORTHEAST SURFACE WINDS INTO
NORTHERN MASS AND PARTS OF CT WHILE SOUTHEAST MASS/RI MAY TURN TO
SOUTH WINDS FOR A TIME DURING THE NIGHT. ALL AREAS TURN TO NORTH
BY FRIDAY MORNING.
FRIDAY...MODERATE CONFIDENCE.
IMPROVING CONDITIONS FRIDAY MORNING AS THE WEATHER SYSTEM MOVES
OFF TO THE EAST. EXPECT MVFR/IFR CONDITIONS IMPROVING TO VFR
BETWEEN SUNRISE AND MIDDAY. CLEARING TREND IN THE CT VALLEY DURING
THE AFTERNOON. NORTHEAST WINDS GUSTING TO 20 KNOTS ALONG THE EAST
COAST.
FRIDAY NIGHT...HIGH CONFIDENCE.
VFR ALL AREAS. AREAS OF IFR/LIFR IN FOG DEVELOPING AFTER MIDNIGHT
ESPECIALLY IN THE CT VALLEY.
KBOS TERMINAL...MODERATE CONFIDENCE IN TAF.
KBDL TERMINAL...MODERATE CONFIDENCE IN TAF.
OUTLOOK /SATURDAY THROUGH TUESDAY/...
SATURDAY...HIGH CONFIDENCE.
VFR. WINDS VEERING E/SE. A MAINLY DRY FORECAST.
SATURDAY NIGHT - SUNDAY NIGHT...MODERATE CONFIDENCE.
MVFR-IFR MIX WITH E/SE-ONSHORE FLOW BACKING SW TOWARDS THE END OF
THE FORECAST PERIOD. RAIN LIKELY ACROSS THE REGION. PATCHY FOG
POSSIBLE. MAY ALSO CONTEND WITH SOME LLWS IMPACTS.
MONDAY INTO TUESDAY...MODERATE CONFIDENCE.
VFR. W/SW-WINDS WITH GUSTS UP TO 20 KTS.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH FRIDAY NIGHT/...HIGH CONFIDENCE IN TRENDS.
MODERATE CONFIDENCE IN SPECIFIC TIMING.
TONIGHT...INCREASING COVERAGE IN SHOWERS AND THUNDERSTORMS.
LOCALLY HEAVY DOWNPOURS POSSIBLE. AREAS OF POOR VISIBILITY IN FOG
ESPECIALLY AROUND NANTUCKET
FRIDAY...LOW PRESSURE LIFTING NE ACROSS THE WATERS. SHOWERS AND
AREAS OF FOG START THE DAY. INCREASING NORTH WINDS WILL REACH 20
KNOTS ON OUR EASTERN WATERS AND COULD GET AS STRONG AS 25 KT. THE
N-NE FETCH SHOULD BE ENOUGH TO BUILD SEAS ON THE EXPOSED EASTERN
WATERS TO 5 FEET...POSSIBLY 6. A SMALL CRAFT ADVISORY HAS BEEN
POSTED ON THE OUTER WATERS AND IN MASS BAY...PRIMARILY FOR SEAS
BUT WITH AN EYE TOWARD THE WINDS AS WELL.
FRIDAY NIGHT...MODERATE CONFIDENCE.
DIMINISHING NORTH TO NORTHWEST WINDS WITH SEAS SUBSIDING AFTER
MIDNIGHT.
OUTLOOK /SATURDAY THROUGH TUESDAY/...
SATURDAY...MODERATE CONFIDENCE.
A LULL IN THE WEATHER. WINDS BECOME LIGHT WHILE VEERING E/SE. SHOULD
SEE SEAS SUBSIDE FOR THE PERIOD BELOW 5-FEET.
SUNDAY...MODERATE CONFIDENCE.
DEEPER AREA OF LOW PRESSURE TO THE W. WILL SEE AN ACCOMPANYING WARM
FRONT LIFT N ACROSS THE WATERS BRINGING WITH IT RAIN ALONG WITH
INCREASING E/SE-ONSHORE WINDS. GUSTS UP TO 20 KTS. WAVE HEIGHTS
BUILDING IN EXCESS OF 5-FEET INITIALLY OVER THE S WATERS EXPANDING
TO THE E/SE WATERS LATE IN THE PERIOD.
MONDAY...MODERATE CONFIDENCE.
IMPROVING. WINDS BACK OUT OF THE W/SW AND REMAIN ROBUST WITH A
STRONG AREA OF LOW PRESSURE SITUATED WELL TO THE W ACROSS THE
INTERIOR. ANOTHER DAY OF GUSTS UP TO 20 KTS WHILE SEAS REMAIN AT OR
IN EXCESS OF 5-FEET ON THE WATERS.
&&
.HYDROLOGY...
GUIDANCE SHOWS RAINFALL AMOUNTS OF UP TO 3 INCHES TONIGHT AND
EARLY FRIDAY. KBOX RADAR HAS ESTIMATED RAINFALL RATES OF 2-4
INCHES/HOUR WITH SOME OF THE SHOWERS TODAY.
MODELS AGREE ON LIFTING THE FRONT NORTH TONIGHT...USING A PIVOT
POINT NEAR NEW YORK CITY...BUT WITH DIFFERENCES ON HOW FAR NORTH.
THE HRRR CARRIES THE FRONT TO THE WORCESTER HILLS. THE GFS BRINGS
THE 925 MB FRONT UP TO NRN RI AND THE SOUTHERN BORDER OF NORFOLK
COUNTY BY 11 PM. WITH DIFFERENCES LIKE THIS...IT IS DIFFICULT TO
FINE-TUNE THE MOST PRONE AREAS FOR HIGH PCPN.
WE HAVE ISSUED A FLASH FLOOD WATCH THAT WILL GO ALONG WITH THE
EARLIER-ISSUED WATCH. BETWEEN THE TWO WATCHES...ALL OF OUR AREA IS
COVERED EXCEPT FOR THE ISLANDS. THE EARLIER WATCH EXPIRES AT
MIDNIGHT...BUT MAY BE EXTENDED. THE LATER WATCH CONTINUES
THROUGH THE NIGHT. BASED ON THE HIGH RAINFALL RATES...ANY FLOODING
THAT DOES DEVELOP SHOULD DO SO QUICKLY.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR CTZ002>004.
MA...FLASH FLOOD WATCH UNTIL MIDNIGHT EDT TONIGHT FOR MAZ017>022.
FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR MAZ002>016-026.
RI...FLASH FLOOD WATCH UNTIL MIDNIGHT EDT TONIGHT FOR RIZ002>007.
FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR RIZ001.
MARINE...SMALL CRAFT ADVISORY FROM 2 AM FRIDAY TO 6 AM EDT SATURDAY FOR
ANZ250-254.
SMALL CRAFT ADVISORY FROM 5 AM TO 4 PM EDT FRIDAY FOR ANZ251.
SMALL CRAFT ADVISORY FROM 2 PM FRIDAY TO 2 AM EDT SATURDAY FOR
ANZ255-256.
&&
$$
SYNOPSIS...WTB/EVT
NEAR TERM...WTB
SHORT TERM...WTB
LONG TERM...EVT
AVIATION...WTB/EVT
MARINE...WTB/EVT
HYDROLOGY...
AREA FORECAST DISCUSSION
NWS TAUNTON MA
352 PM EDT THU SEP 10 2015
.SYNOPSIS...
A FRONT STALLED ALONG THE SOUTHERN NEW ENGLAND SOUTH COAST WILL
PUSH NORTH OVERNIGHT AND PROVIDE A FOCUS FOR LOCALLY HEAVY
DOWNPOURS DURING THE NIGHT. LOW PRESSURE FROM THE MID ATLANTIC
STATES WILL MOVE NORTHEAST PAST OUR AREA FRIDAY MORNING. WEAK
HIGH PRESSURE THEN BRINGS A LULL IN THE WEATHER SATURDAY. WET-
WEATHER RETURNS FOR SUNDAY BUT NOT APPEARING TO BE A WASHOUT.
PERHAPS SOME HEAVY RAIN FOR THE HIGH TERRAIN AND SOUTHEAST NEW
ENGLAND. TURNING DRY AND WARMER INTO NEXT WEEK. COULD BE LOOKING
AT THE POSSIBILITY OF RECORD BREAKING HEAT INTO MID- TO LATE-
SEPTEMBER AS ABOVE-AVERAGE TEMPS ARE FORECAST.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
A COLD FRONT LIES NORTH OF NANTUCKET BUT SOUTH OF THE REMAINDER OF
NEW ENGLAND AND LONG ISLAND. SOUTHWEST FLOW ALOFT HAS A FAINT
SHORTWAVE MOVING THROUGH WITH LOW LEVEL FLOW DRAWING VERY MOST AIR
NORTH OVER THE TOP OF THE FRONT. PRECIPITABLE WATER VALUES
CONTINUE EITHER SIDE OF 2 INCHES...WHICH IS ABOUT AS HIGH AS IT
GETS IN SOUTHERN NEW ENGLAND IN SEPTEMBER.
THE SURFACE FRONT SUPPORTS LOW LEVEL CONVERGENCE AND THE UPPER
SHORTWAVE SUPPORTS UPPER VENTING...AND THIS WILL BE WORKING ON A
VERY JUICY AIRMASS. WE WILL CONTINUE WITH CATEGORICAL POPS FOR
SHOWERS/SCATTERED TSTMS THIS EVENING AND TONIGHT. BASED ON THE
HIGH PW AIR...WE CONTINUE TO EXPECT LOCALLY HEAVY DOWNPOURS THAT
WILL BRING LOCALLY HEAVY DOWNPOURS. BEST CHANCE WILL BE WITH THE
BEST LIFT ALONG AND NORTH OF THE FRONT.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
COASTAL LOW PRESSURE MOVES OFF TO THE EAST FRIDAY
MORNING...CARRYING ANY REMAINING PCPN OFF TO THE EAST. MODEL
MOISTURE FIELDS SHOW DRYING FROM WEST TO EAST DURING THE
DAY...SUGGESTING A CLEARING TREND FRIDAY AFTERNOON INTO FRIDAY
NIGHT.
MEANWHILE...A LARGER UPPER SHORTWAVE DIGS OVER THE GREAT LAKES AND
MAINTAINS A SOUTHWEST FLOW ALOFT. THE SUPPORTING UPPER JET WILL BE
POSITIONED OVER THE EASTERN GREAT LAKES...GENERATING MORE CONVECTION
IN THAT AREA WHILE NEW ENGLAND HAS WEAK SUBSIDENCE. SO FRIDAY
AFTERNOON AND NIGHT SHOULD BE A DRY PERIOD. NORTH WIND FRIDAY WILL
DIMINISH FRIDAY NIGHT INLAND.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
*/ HIGHLIGHTS...
- KEEPING IT DRY ON SATURDAY
- WET WEATHER FOR SUNDAY BUT NOT LOOKING LIKE A WASHOUT EVERYWHERE
- HEAVY RAIN THOUGH MAY IMPACT SE NEW ENGLAND ... HIGH TERRAIN
- DRY AND WARM INTO NEXT WEEK ... POSSIBLE RECORD BREAKING HEAT
*/ DISCUSSION...
KEEPING WITH AN ENSEMBLE APPROACH. H5 DEEP-TROUGH CLOSED LOW SWEEPS
THROUGH THE OHIO-RIVER VALLEY SATURDAY AHEAD OF WHICH THERE IS RIDGE-
AMPLIFICATION KEEPING US MOSTLY DRY WITH LIKELY SOME MID-HIGH LEVEL
CLOUDS ACROSS THE REGION. LIFTING E SUNDAY DIFFLUENCE PROCEEDS ABOVE
LOW-MID LEVEL LIFT / CONVERGENCE BUT CONVINCED S NEW ENGLAND IS IN
AN AREA OF LESS FAVORABLE DEVELOPMENT. TWO AREAS OF INTEREST: THE
CYCLONIC TROWALING ROUND THE CLOSED LOW BACK INTO THE E GREAT LAKES
WHERE DEFORMATION PROCEEDS...AND SE NEW ENGLAND AND POINTS OFFSHORE
WITHIN THE ANTI-CYCLONIC BRANCH OF THE WARM CONVEYOR BELT WHERE HIGH
THETA-E VALUES RESIDE BENEATH DIFFLUENCE AND ENHANCED ASCENT WITH
CONVERGENCE ALONG A STRONG H925-7 JET. S NEW ENGLAND BELOW THE RIGHT-
FRONT-QUADRANT OF THE UPPER-LEVEL-JET AND IN THE CROSS-HAIRS OF A
MID-LEVEL DRY-PUNCH WRAPPING INTO THE OCCLUDING SYSTEM PER ENSEMBLE
MEANS LOOKS TO RESULT IN LITTLE OUTCOME OVER THE AREA. IN OTHER
WORDS...NOT APPEARING TO BE A WASHOUT ON SUNDAY. CAN NOT RULE OUT
HIGHER AMOUNTS OVER THE HIGHER TERRAIN.
WITH ENSEMBLES LIFTING THE TROWAL N OF THE REGION SUNDAY NIGHT INTO
MONDAY...LESS CONFIDENCE OF OUTCOMES ON MONDAY BENEATH THE COLD POOL
AS THE TROUGH MAY MOVE THRU PRIOR TO BOUNDARY-LAYER DESTABILIZATION.
PERHAPS SOME ACTIVITY UP AGAINST THE W-SLOPES OF HIGHER TERRAIN N OF
OUR AREA WITH W-WIND CONVERGENCE.
FOR THE REMAINDER OF THE WEEK...CONSISTENT SIGNALS OF RIDGING. THINK
HEAT AND HUMIDITY BUILD BACK INTO THE REGION. AGREE WITH THE CLIMATE
PREDICTION CENTER WITH ABOVE-AVERAGE TEMPERATURES. ENSEMBLES SIGNAL
ANOMALOUS H85 TEMPERATURES ACROSS THE REGION. THINKING THAT WE COULD
BREAK SOME RECORD HIGH TEMPERATURES INTO MID- TO LATE-SEPTEMBER.
&&
.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH FRIDAY NIGHT/...
TONIGHT...MODERATE CONFIDENCE. IFR AND SOME LIFR CIGS/VSBYS IN
SHOWERS/TSTMS WITH HEAVY DOWNPOURS. NORTHEAST SURFACE WINDS INTO
NORTHERN MASS AND PARTS OF CT WHILE SOUTHEAST MASS/RI MAY TURN TO
SOUTH WINDS FOR A TIME DURING THE NIGHT. ALL AREAS TURN TO NORTH
BY FRIDAY MORNING.
FRIDAY...MODERATE CONFIDENCE.
IMPROVING CONDITIONS FRIDAY MORNING AS THE WEATHER SYSTEM MOVES
OFF TO THE EAST. EXPECT MVFR/IFR CONDITIONS IMPROVING TO VFR
BETWEEN SUNRISE AND MIDDAY. CLEARING TREND IN THE CT VALLEY DURING
THE AFTERNOON. NORTHEAST WINDS GUSTING TO 20 KNOTS ALONG THE EAST
COAST.
FRIDAY NIGHT...HIGH CONFIDENCE.
VFR ALL AREAS. AREAS OF IFR/LIFR IN FOG DEVELOPING AFTER MIDNIGHT
ESPECIALLY IN THE CT VALLEY.
KBOS TERMINAL...MODERATE CONFIDENCE IN TAF.
KBDL TERMINAL...MODERATE CONFIDENCE IN TAF.
OUTLOOK /SATURDAY THROUGH TUESDAY/...
SATURDAY...HIGH CONFIDENCE.
VFR. WINDS VEERING E/SE. A MAINLY DRY FORECAST.
SATURDAY NIGHT - SUNDAY NIGHT...MODERATE CONFIDENCE.
MVFR-IFR MIX WITH E/SE-ONSHORE FLOW BACKING SW TOWARDS THE END OF
THE FORECAST PERIOD. RAIN LIKELY ACROSS THE REGION. PATCHY FOG
POSSIBLE. MAY ALSO CONTEND WITH SOME LLWS IMPACTS.
MONDAY INTO TUESDAY...MODERATE CONFIDENCE.
VFR. W/SW-WINDS WITH GUSTS UP TO 20 KTS.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH FRIDAY NIGHT/...HIGH CONFIDENCE IN TRENDS.
MODERATE CONFIDENCE IN SPECIFIC TIMING.
TONIGHT...INCREASING COVERAGE IN SHOWERS AND THUNDERSTORMS.
LOCALLY HEAVY DOWNPOURS POSSIBLE. AREAS OF POOR VISIBILITY IN FOG
ESPECIALLY AROUND NANTUCKET
FRIDAY...LOW PRESSURE LIFTING NE ACROSS THE WATERS. SHOWERS AND
AREAS OF FOG START THE DAY. INCREASING NORTH WINDS WILL REACH 20
KNOTS ON OUR EASTERN WATERS AND COULD GET AS STRONG AS 25 KT. THE
N-NE FETCH SHOULD BE ENOUGH TO BUILD SEAS ON THE EXPOSED EASTERN
WATERS TO 5 FEET...POSSIBLY 6. A SMALL CRAFT ADVISORY HAS BEEN
POSTED ON THE OUTER WATERS AND IN MASS BAY...PRIMARILY FOR SEAS
BUT WITH AN EYE TOWARD THE WINDS AS WELL.
FRIDAY NIGHT...MODERATE CONFIDENCE.
DIMINISHING NORTH TO NORTHWEST WINDS WITH SEAS SUBSIDING AFTER
MIDNIGHT.
OUTLOOK /SATURDAY THROUGH TUESDAY/...
SATURDAY...MODERATE CONFIDENCE.
A LULL IN THE WEATHER. WINDS BECOME LIGHT WHILE VEERING E/SE. SHOULD
SEE SEAS SUBSIDE FOR THE PERIOD BELOW 5-FEET.
SUNDAY...MODERATE CONFIDENCE.
DEEPER AREA OF LOW PRESSURE TO THE W. WILL SEE AN ACCOMPANYING WARM
FRONT LIFT N ACROSS THE WATERS BRINGING WITH IT RAIN ALONG WITH
INCREASING E/SE-ONSHORE WINDS. GUSTS UP TO 20 KTS. WAVE HEIGHTS
BUILDING IN EXCESS OF 5-FEET INITIALLY OVER THE S WATERS EXPANDING
TO THE E/SE WATERS LATE IN THE PERIOD.
MONDAY...MODERATE CONFIDENCE.
IMPROVING. WINDS BACK OUT OF THE W/SW AND REMAIN ROBUST WITH A
STRONG AREA OF LOW PRESSURE SITUATED WELL TO THE W ACROSS THE
INTERIOR. ANOTHER DAY OF GUSTS UP TO 20 KTS WHILE SEAS REMAIN AT OR
IN EXCESS OF 5-FEET ON THE WATERS.&&
.HYDROLOGY...
GUIDANCE SHOWS RAINFALL AMOUNTS OF UP TO 3 INCHES TONIGHT AND
EARLY FRIDAY. KBOX RADAR HAS ESTIMATED RAINFALL RATES OF 2-4
INCHES/HOUR WITH SOME OF THE SHOWERS TODAY.
MODELS AGREE ON LIFTING THE FRONT NORTH TONIGHT...USING A PIVOT
POINT NEAR NEW YORK CITY...BUT WITH DIFFERENCES ON HOW FAR NORTH.
THE HRRR CARRIES THE FRONT TO THE WORCESTER HILLS. THE GFS BRINGS
THE 925 MB FRONT UP TO NRN RI AND THE SOUTHERN BORDER OF NORFOLK
COUNTY BY 11 PM. WITH DIFFERENCES LIKE THIS...IT IS DIFFICULT TO
FINE-TUNE THE MOST PRONE AREAS FOR HIGH PCPN.
WE HAVE ISSUED A FLASH FLOOD WATCH THAT WILL GO ALONG WITH THE
EARLIER-ISSUED WATCH. BETWEEN THE TWO WATCHES...ALL OF OUR AREA IS
COVERED EXCEPT FOR THE ISLANDS. THE EARLIER WATCH EXPIRES AT
MIDNIGHT...BUT MAY BE EXTENDED. THE LATER WATCH CONTINUES
THROUGH THE NIGHT. BASED ON THE HIGH RAINFALL RATES...ANY FLOODING
SHOULD DEVELOP QUICKLY.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR CTZ002>004.
MA...FLASH FLOOD WATCH UNTIL MIDNIGHT EDT TONIGHT FOR MAZ017>022.
FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR MAZ002>016-026.
RI...FLASH FLOOD WATCH UNTIL MIDNIGHT EDT TONIGHT FOR RIZ002>007.
FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR RIZ001.
MARINE...SMALL CRAFT ADVISORY FROM 2 AM FRIDAY TO 6 AM EDT SATURDAY FOR
ANZ250-254.
SMALL CRAFT ADVISORY FROM 5 AM TO 4 PM EDT FRIDAY FOR ANZ251.
SMALL CRAFT ADVISORY FROM 2 PM FRIDAY TO 2 AM EDT SATURDAY FOR
ANZ255-256.
&&
$$
SYNOPSIS...WTB/BDS
NEAR TERM...WTB
SHORT TERM...WTB
LONG TERM...BDS
AVIATION...WTB/BDS
MARINE...WTB/BDS
HYDROLOGY...
AREA FORECAST DISCUSSION
NWS ALBANY NY
1025 AM EDT THU SEP 10 2015
.SYNOPSIS...
A WAVE OF LOW PRESSURE WILL MOVE ALONG A COLD FRONT THAT
HAS STALLED SOUTH OF THE REGION THIS AFTERNOON AND TONIGHT. THIS
WILL BRING SHOWERS TO THE REGION...WITH A SOAKING RAINFALL LIKELY
FROM THE CAPITAL REGION AND POINTS SOUTH AND EAST THIS AFTERNOON AND
TONIGHT. THE LOW WILL MOVE OFF THE NEW ENGLAND COAST FRIDAY...WITH
SHOWERS ENDING EARLY. ANOTHER STORM SYSTEM SHOULD BRING SHOWERS TO
THE REGION LATE SATURDAY INTO SUNDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 1025 AM EDT...THE RAP GUIDANCE WITH THE IR SATELLITE
PICTURE OVERLAYED SHOWS LOW PRESSURE ORGANIZING NEAR THE DELMARVA
REGION THIS MORNING. THE HEAVIEST SHOWERS AND THUNDERSTORMS REMAIN
WELL SOUTH AND EAST OF THE AREA NEAR LONG ISLAND AND EXTREME SE
NEW ENGLAND AND CAPE COD. SOME OVER RUNNING MOISTURE CONTINUES TO
MOVE N/NE FROM CNTRL PA/CNTRL NY IN THE NRN CATSKILLS...CAPITAL
REGION AND SRN VT. WE HAVE RETOOLED THE POPS BASED ON THE LOCAL
AND REGIONAL RADAR TRENDS AS THE SHORT-WAVE APPROACHES FROM THE OH
VALLEY WHICH WILL ENHANCE THE SHOWERS WITH THE WAVE DEVELOPING.
ALSO...A STRONG UPPER LEVEL JET MAX WILL BE TRANSLATING NORTHEAST
ACROSS EASTERN QUEBEC...WITH OUR REGION WITHIN THE RIGHT ENTRANCE
REGION. THE AGEOSTROPHIC RESPONSE TO THIS FEATURE WILL ALLOW
DIVERGENCE AND MID LEVEL FRONTOGENETIC FORCING TO INCREASE ACROSS
THE REGION LATE THIS MORNING AND ESPECIALLY THIS AFTERNOON AND
EVENING...ALLOWING SHOWERS OR EVEN A STEADY RAIN SHIELD TO DEVELOP
AND ADVANCE NORTH NORTHEAST FROM THE MID ATLANTIC STATES.
SO...INCREASING CHANCES FOR SHOWERS OR STEADY RAIN THIS AFTERNOON
FROM SOUTH TO NORTH...WITH THE STEADIEST RAIN MAINLY REMAINING
NEAR AND SOUTH AND EAST OF THE I-90/I-88 CORRIDORS. IT MAY TAKE
UNTIL LATE AFTERNOON OR CLOSER TO SUNSET FOR THIS RAIN TO REACH
THE LAKE GEORGE/GLENS FALLS AREA...AS WELL AS THE SOUTHWEST
ADIRONDACKS...WHICH MAY ESCAPE MUCH OF THE STEADIER RAIN.
ACROSS THE SOUTHEAST CATSKILLS...MID HUDSON VALLEY...NW CT AND SW
MA...DEEPER MOISTURE AND SOME ELEVATED INSTABILITY MAY ALLOW FOR
SOME EMBEDDED CONVECTIVE ELEMENTS TO DEVELOP THIS AFTERNOON WHICH
COULD PRODUCE LOCALLY HEAVY DOWNPOURS. SOME RUMBLES OF THUNDER
WILL BE POSSIBLE IN THESE AREAS LATER TODAY. WE REDUCED THE
THE AREA FOR A SLIGHT CHC OF THUNDER TO ONLY LOCATIONS SOUTH OF
THE CAPITAL REGION PRIOR TO 8 PM DUE TO A MORE STABLE ENVIRONMENT
BASED ON THE 12Z KALY SOUNDING. THIS IS ROUGHLY FROM THE SRN
BERKS...COLUMBIA AND GREENE COUNTIES SOUTH.
IT WILL BE MUCH COOLER REGIONWIDE COMPARED TO RECENT DAYS...WITH
MAX TEMPS MAINLY REACHING THE LOWER TO MID 70S IN VALLEYS...AND
MID 60S TO LOWER 70S ACROSS HIGHER TERRAIN.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
TONIGHT...THE AFOREMENTIONED UPPER LEVEL DYNAMICS AND FORCING FROM
THE FRONTAL WAVE TO OUR SOUTHEAST...AND UPPER LEVEL JET TO OUR
NORTH SHOULD BE MAXIMIZED ACROSS THE REGION BEFORE
MIDNIGHT...LEADING TO THE BEST CHANCES FOR RAIN. FAR NW PORTIONS
OF THE REGION...SUCH AS NORTHERN HERKIMER AND HAMILTON COS MAY
JUST ESCAPE MUCH OF THIS RAIN. THE HEAVIEST RAIN SHOULD CONTINUE
TO BE AREAS SOUTH AND EAST OF THE GREATER CAPITAL REGION...WHERE
SOME RUMBLES OF THUNDER WILL REMAIN POSSIBLE THROUGH MIDNIGHT.
EVENTUALLY...AS THE WAVE PASSES FURTHER EAST...AND THE UPPER LEVEL
DYNAMICS WEAKEN...WE EXPECT THE RAIN TO TAPER OFF FROM W TO E
ACROSS THE REGION AFTER MIDNIGHT. SOME SHOWERS OR PATCHY DRIZZLE
SHOULD LINGER THROUGH OR AFTER DAYBREAK FOR AREAS NEAR AND ESP
EAST OF THE HUDSON RIVER. MIN TEMPS TONIGHT SHOULD FALL INTO THE
MID 50S TO LOWER 60S.
FRIDAY...SOME SPOTTY SHOWERS OR DRIZZLE MAY CONTINUE ACROSS
PORTIONS OF THE EASTERN CATSKILLS...CAPITAL REGION...SOUTHERN
VT...THE BERKSHIRES AND NW CT IN THE MORNING...BEFORE TAPERING
OFF BY EARLY AFTERNOON. ELSEWHERE...THE RAIN SHOULD HAVE ENDED BY
DAYBREAK. CLOUDS MAY BE TOUGH TO ERODE GIVEN THE MOIST BOUNDARY
LAYER...BUT SOME CLEARING IS EXPECTED TO DEVELOP IN THE AFTERNOON.
MAX TEMPS SHOULD REACH THE MID/UPPER 70S IN LOWER
ELEVATIONS...WITH MAINLY 60S TO LOWER 70S ACROSS HIGHER TERRAIN.
FRI NT...GENERALLY DRY WEATHER AND COOL...WITH MIN TEMPS FALLING
INTO THE 50S IN MANY AREAS. SOME 40S WILL BE POSSIBLE ACROSS
PORTIONS OF THE SOUTHERN ADIRONDACKS...AND ALSO HIGHER TERRAIN IN
SOUTHERN VT AND WESTERN MA.
SAT-SAT NT...A RATHER DYNAMIC UPPER LEVEL SYSTEM WILL BE
DEVELOPING ACROSS THE LOWER GREAT LAKES/OHIO VALLEY REGION DURING
THIS TIME...ALLOWING A SFC LOW TO DEVELOP ACROSS THE NORTHERN
APPALACHIANS...WITH A SECONDARY LOW POSSIBLY DEVELOPING NEAR THE
DELMARVA PENINSULA. INCREASING ISENTROPIC LIFT SHOULD ALLOW
SHOWERS TO DEVELOP AND TRANSLATE EASTWARD SAT AFTERNOON AND
NIGHT. IT IS POSSIBLE THAT THE RAIN IS SLOW TO DEVELOP ACROSS
EASTERN AREAS...AS THE BEST FORCING MAY REMAIN TO THE WEST AND
SOUTH THROUGH MUCH OF SAT. SO...INDICATING SLOWLY INCREASING POPS
FROM W TO E SAT...IN THE CHC RANGE...THEN LIKELY POPS FOR SAT NT.
SOME EMBEDDED THUNDERSTORMS COULD OCCUR SAT NT AS SHOWALTER
INDICES ARE FORECAST TO DROP BELOW ZERO...IN COMBINATION WITH
STRONG DYNAMICAL LIFT. MAX TEMPS SAT SHOULD REACH THE MID TO UPPER
70S IN VALLEYS...AND 60S ACROSS HIGHER TERRAIN. HOWEVER...SHOULD
RAIN DEVELOP SOONER...MUCH COOLER MAX TEMPS WOULD BE POSSIBLE. SAT
NT/SUN AM MINS SHOULD FALL INTO THE 50S TO LOWER 60S.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
THE LONG TERM PERIOD LOOKS TO START UNSETTLED AS A COMPLEX LOW
PRESSURE SYSTEM LIFTS THROUGH THE NORTHEAST ON SUNDAY INTO MONDAY.
WHILE MODELS ARE IN FAIRLY GOOD AGREEMENT WITH A LONG WAVE TROUGH
OVER THE EASTERN UNITED STATES...THEY DIFFER IN LOCATION OF BOTH THE
UPPER CLOSED LOW AND SURFACE LOW PRESSURE SYSTEMS. THE ECMWF IS
FARTHER NORTH THAN THE GFS WITH BOTH THE UPPER CLOSED LOW AND
SURFACE LOW PRESSURE SYSTEMS AND AS A RESULT HAS THE PCPN LIFTING
NORTH AND EAST OF FA QUICKER THAN THE GFS WHICH LINGERS PCPN INTO
MONDAY EVENING. FOR NOW WILL KEEP PCPN ACRS MUCH OF FA THROUGH
MONDAY WITH IMPROVING CONDITIONS MONDAY NIGHT. QPF AMOUNTS LOOK TO
BE BETWEEN A THIRD OF AN INCH AND AN INCH FOR SUNDAY AND SUNDAY
NIGHT. EXPECT RELATIVELY COOL CONDITIONS SUNDAY THROUGH MONDAY GIVEN
CLOUD COVER AND PCPN. HIGHS ON SUNDAY ARE EXPECTED TO BE IN THE MID
60S TO LOWER 70S WITH LOWS SUNDAY NIGHT IN THE UPPER 40S TO UPPER
50S AND HIGHS ON MONDAY IN THE UPPER 50S TO LOWER 70S.
IMPROVING CONDITIONS ARE EXPECTED FOR THE REMAINDER OF THE LONG TERM
PERIOD FROM MONDAY NIGHT THROUGH WEDNESDAY AS A LARGE RIDGE OF HIGH
PRESSURE BUILDS NORTHEAST FROM THE CENTRAL APPALACHIANS MONDAY NIGHT
INTO THE NORTHEAST TUESDAY NIGHT INTO WEDNESDAY. LOWS MONDAY NIGHT
ARE EXPECTED TO BE IN THE MID 40S TO MID 50S WITH HIGHS ON TUESDAY
IN THE UPPER 60S TO UPPER 70S. LOWS TUESDAY NIGHT ARE EXPECTED TO BE
IN THE MID 40S TO LOWER 50S WITH HIGHS ON WEDNESDAY IN THE MID 70S
TO LOWER 80S.
&&
.AVIATION /14Z THURSDAY THROUGH MONDAY/...
A FRONTAL SYSTEM TO OUR SOUTH AND EAST WILL STALL TODAY...AS A
WAVE OF LOW PRESSURE MOVES ALONG IT THIS AFTERNOON AND TONIGHT.
THIS WILL BRING SHOWERS TO THE REGION...WITH A SOAKING RAINFALL
LIKELY FROM THE CAPITAL REGION AND POINTS SOUTH AND EAST THIS
AFTERNOON AND TONIGHT. THE GREATEST IMPACT ON THE TAF SITES WILL
BE AT KPOU WITH LESSER IMPACTS FARTHER NORTH. CONDITIONS WILL
GENERALLY BE VFR/MVFR THROUGH TONIGHT...ALTHOUGH CANNOT RULE OUT
SOME BRIEF PERIODS OF IFR PARTICULARLY AT KPOU AND KPSF.
LIGHT AND VARIABLE WINDS WILL BECOME NORTHERLY AT LESS THAN 10
KNOTS AND CONTINUE THROUGH TONIGHT.
OUTLOOK...
FRIDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
SATURDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA.
SATURDAY NIGHT: MODERATE OPERATIONAL IMPACT. LIKELY SHRA.
SUNDAY: MODERATE OPERATIONAL IMPACT. LIKELY SHRA.
SUNDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA.
MONDAY: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA.
&&
.FIRE WEATHER...
A DEVELOPING WAVE OF LOW PRESSURE TRACKING ALONG A FRONTAL
BOUNDARY TO OUR SOUTHEAST SHOULD BRING A SOAKING RAINFALL TO MOST
OF THE REGION THIS AFTERNOON AND TONIGHT. HOWEVER...ONLY SPOTTY
LIGHT RAIN OR SPRINKLES ARE EXPECTED ACROSS THE WESTERN
ADIRONDACKS IN EXTREME NORTHERN HERKIMER/HAMILTON COS...AND NW
WARREN CO.
THE RH SHOULD FALL INTO THE 50-70 PERCENT RANGE THIS
AFTERNOON...EXCEPT 40-50 PERCENT ACROSS NORTHERN HERKIMER AND
HAMILTON COS. THE RH SHOULD RECOVER TO 90-100 PERCENT
TONIGHT...THEN FALL TO 45-60 PERCENT FRI AFTERNOON.
WINDS WILL BECOME NORTH TO NORTHEAST AT 5-10 MPH TODAY AND
TONIGHT...ALTHOUGH SLIGHTLY HIGHER WINDS OF 10-20 MPH COULD OCCUR
TONIGHT ACROSS THE HIGHER PEAKS OF THE GREEN MTNS...BERKSHIRES AND
TACONICS. WINDS WILL BECOME MAINLY NORTH ON FRIDAY AT 5-15 MPH.
&&
.HYDROLOGY...
RAINFALL AMTS OF 1 TO 2 INCHES ARE EXPECTED FROM THE SOUTHEAST
CATSKILLS...MID HUDSON VALLEY REGION...NW CT...WESTERN MA AND
SOUTHERN VT THROUGH FRI MORNING. GENERALLY UNDER AN INCH IS
EXPECTED TO THE N AND W OF THESE AREAS...WITH LITTLE IF ANY RAIN
OCCURRING ACROSS THE WESTERN ADIRONDACKS.
ALTHOUGH MAIN STEM RIVERS WILL ONLY EXHIBIT MINOR RISES FROM THIS
RAINFALL DUE TO DRY ANTECEDENT CONDITIONS...LOCALLY HEAVY
DOWNPOURS AND RAINFALL RATES OF ONE HALF INCH PER HOUR OR SLIGHTLY
GREATER COULD LEAD TO PONDING OF WATER IN LOW LYING...URBAN AND
POOR DRAINAGE AREAS THIS AFTERNOON AND TONIGHT...ESP ACROSS THE
MID HUDSON VALLEY...NW CT...AND WESTERN MA.
THE NEXT THREAT OF RAIN WILL ARRIVE LATE SATURDAY INTO SUNDAY AS A
LOW PRESSURE SYSTEM APPROACHES FROM THE SOUTH AND WEST. MODERATE
RAINFALL AMTS...POSSIBLY IN THE ONE HALF INCH TO ONE AND ONE HALF
INCH RANGE COULD OCCUR...LEADING TO ADDITIONAL MINOR RISES ON AREA
RIVERS/STREAMS.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...KL/WASULA
NEAR TERM...KL/WASULA
SHORT TERM...KL
LONG TERM...11
AVIATION...11
FIRE WEATHER...HWJIV/KL
HYDROLOGY...HWJIV/KL
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
955 PM EDT FRI SEP 11 2015
.DISCUSSION...
...HIGHER RAIN CHANCES THIS WEEKEND...
.UPDATE...LINGERING SCATTERED STORMS WILL PUSH OFF THE ST LUCIE AND MARTIN
COUNTY COAST THROUGH MIDNIGHT. FINAL EVENING UPDATE KEPT SCATTERED ACTIVITY
FOR A FEW MORE HOURS ALONG THE TREASURE COAST AND A SLIGHT CHANCE FOR A STORM
NORTHWARD INTO BREVARD COUNTY UNTIL AROUND MIDNIGHT. CONVECTIVE CLOUDINESS
SHOULD THIN LATER TONIGHT ACROSS THE SOUTH AS MID AND HIGH LEVEL CLOUDS INCREASE
ACROSS NRN AREAS TWD SUNRISE. HRRR FORMS PREFRONTAL SHOWER AND THUNDERSTORM LINE
ACROSS THE NE GULF LATE TONIGHT BUT SHOULD NOT ARRIVE INTO LAKE COUNTY AND
NRN SECTIONS UNTIL MID MORNING. LOWS IN THE LOWER TO MID 70S.
.PREVIOUS DISCUSSION...
TONIGHT AND SATURDAY...SHOWERS/STORMS OVER THE TREASURE
COAST AND LAKE OKEECHOBEE SHOULD BEGIN TO DIMINISH BY AROUND 10 PM.
THERE IS EXPECTED TO BE A LULL IN PCPN OVERNIGHT...HOWEVER EARLY
SHOWERS ARE EXPECTED ALONG THE GULF CST SAT MORNING IN RESPONSE TO THE
APPROACHING SHORTWAVE MOVING INTO THE SE STATES. DETERIORATING
WEATHER CONDITIONS WL UNFOLD FROM N TO S DURING SATURDAY AS THE AXIS
OF THE UNSEASONABLY STRONG WAVE APCHS THE REGION.
AMPLE MOISTURE COMBINED WITH FORCED ASCENT FROM LATE MORNING
THROUGH THE AFTERNOON WILL BRING NUMEROUS SHOWERS AND STORMS
INITIALLY TO THE I-4 CORRIDOR BY LATE MORNING MID DAY THEN SWD
ACROSS THE REMAINDER OF THE AREA THROUGH THE AFTERNOON. THERE IS
A CHANCE FOR STRONG STORMS AS CELL MOTION WILL BE RATHER QUICK
(20-25 KNOTS). WHERE STRONGEST HEATING/INSTABILITY OCCURS A
MARGINAL RISK FOR DAMAGING WINDS EXISTS.
SUNDAY...(MODIFIED PREV DISC) THE SHORTWAVE WILL LIFT AWAY FROM
AREA AS A 250MB JET CORE NR 100-120 KNOTS RIDES UP INTO NEW
ENGLAND. A LINGERING MOISTURE BAND IS FORECAST ACROSS THE AREA
WITH AN ASCD SFC FRONT/TROUGH SHOWN CREEPING TO NEAR NORTHERN
SECTIONS BY LATE SUN. RAIN COVERAGE WL REMAIN ABOVE AVERAGE AND WL
KEEP 50-60 PERCENT IN PLACE.
MON-THU...UPPER TROUGH OVER THE EAST QUICKLY LIFTS WHILE SURFACE
HIGH PRESSURE PUSHES OFF THE MID ATLANTIC. WHATEVER IS LEFT OF THE
SURFACE FRONTAL BOUNDARY WILL WASH OUT OVER THE AREA...PUTTING
CENTRAL FLORIDA IN LOW LEVEL EASTERLY FLOW FOR THE EARLY PART OF
NEXT WEEK. MOISTURE IS PROGGED TO REMAIN HIGH THROUGH THE PERIOD
SO POPS WILL CONTINUE HIGHER THAN NORMAL FOR MID SEPTEMBER. THE
HIGHEST VALUES SHOULD FAVOR THE INTERIOR DUE TO EASTERLY GRADIENT
WINDS AND WEAK STEERING LEVEL FLOW.
&&
.AVIATION...
EVENING SHRA/TSRA SHOULD MAINLY STAY SOUTH OF A KISM-KTIX LINE THROUGH
03Z. INCRSG SHRA AND EMBEDDED TS N OF A LINE FM KLEE-KDAB AFT
12/14Z SPREADING SOUTH INTO THE AFTERNOON HOURS ON SATURDAY.
&&
.MARINE...
TONIGHT AND SATURDAY...WLY GRADIENT WINDS AROUND 10 TO 15 KTS WITH
OCCASIONAL HIGHER GUSTS MAINLY OVER THE OPEN OUTER WATERS. FETCH
LIMITED CONDITIONS WL BRING HIGHEST SEAS OFFSHORE ~3FT. THE MAIN
WEEKEND ISSUE WILL BE LOCALLY HIGHER WINDS AND SEAS ASCD WITH FAST
MOVING SHOWERS AND STORMS FROM THE MAINLAND. MARINERS SHOULD
FOLLOW THE LATEST OUTLOOKS AS THIS PATTERN WILL FAVOR ISSUANCE OF
MARINE WARNINGS.
MON-TUE...THE FRONTAL BOUNDARY SHOULD WASH OUT OVER THE NORTHERN
WATERS. WINDS WILL BECOME NORTHEAST-EAST 10 TO 15 KNOTS. THIS
WILL GENERATE MORE OF A WIND CHOP. THERE WILL BE A CONTINUED
CHANCE OF SHOWERS AND STORMS BOTH DAYS. MON WILL STILL HAVE A
CHANCE FOR STRONG AFTERNOON STORMS MOVING OFF THE MAINLAND. THEN
BY TUE SHOWERS/STORMS WILL MOVE SLOWLY WEST-NORTHWESTWARD AS
ONSHORE FLOW DEEPENS A LITTLE.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 75 84 71 84 / 30 80 50 50
MCO 75 87 73 84 / 20 70 40 50
MLB 76 90 73 86 / 30 50 50 60
VRB 76 89 72 87 / 30 50 50 60
LEE 75 85 72 85 / 20 80 50 50
SFB 75 85 73 84 / 20 70 40 50
ORL 75 87 74 85 / 20 70 40 50
FPR 75 90 72 88 / 30 50 50 60
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
VOLKMER/SEDLOCK
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
356 PM EDT THU SEP 10 2015
.SYNOPSIS...
19Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS A BROAD BUT AMPLIFIED
UPPER LEVEL PATTERN IN PLACE OVER THE CONUS LATE THIS AFTERNOON.
PATTERN CONSISTS OF RIDGING OVER THE PACIFIC COAST/INTER-MOUNTAIN
WEST...FOLLOWED DOWNSTREAM BY LONGWAVE TROUGHING FROM THE CENTRAL
PLAINS TO THE EASTERN SEABOARD. VERY GOOD CONSENSUS AMONG THE
GUIDANCE MEMBERS THAT THIS EASTERN CONUS TROUGH WILL UNDERGO MORE
SIGNIFICANT AMPLIFICATION DURING THE NEXT 24-30 HOURS...AS A A
SERIES OF STRONG SHORTWAVE IMPULSES CURRENTLY OVER THE UPPER MS
VALLEY AND SOUTHERN CANADA DROP QUICKLY INTO THE LONGWAVE
CYCLONIC FLOW. THIS STRONG AMPLIFICATION TO THE PATTERN WILL
IMPACT OUR LOCAL WEATHER BY SATURDAY WHEN ONE OF THE DEEPEST
SOUTHWARD PENETRATIONS OF A FRONTAL SYSTEM SEEN IN SEVERAL MONTHS
TAKES PLACE. NO...THIS FRONT IS NOT EXPECTED TO BRING US ANY
SIGNIFICANT RELIEF FROM THE SUMMER HEAT AND HUMIDITY AS IT QUICKLY
DECAYS ONCE REACHING NORTHERN FLORIDA. HOWEVER...IT IS LIKELY TO
BRING WIDESPREAD SHOWER ACTIVITY TO THE REGION FOR THE FIRST HALF
OF THE WEEKEND...AND IS A FIRST SIGN FOR THIS PART OF THE COUNTRY
THAT THE SEASONS ARE JUST NOW BEGINNING TO CHANGE.
CURRENTLY AHEAD OF ALL THIS...WE FIND OUR FORECAST AREA UNDER A
LARGE DOME OF MID/UPPER LEVEL RIDGING THAT EXTENDS SOUTHWARD AND
EASTWARD TO CUBA AND THE BAHAMA ISLANDS. THE LOWER LEVELS ARE
DOMINATED BY THE SUBTROPICAL RIDGE AXIS THAT EXTENDS ACROSS THE
CENTRAL/SOUTHERN FL PENINSULA AND EASTERN GULF OF MEXICO. BOTH OF
THESE FEATURES WILL BE WEAKENING AND PUSHING SOUTHWARD IN THE NEXT
24 HOURS IN RESPONSE TO THE AMPLIFYING TROUGH TO OUR NORTH.
REGIONAL RADARS AS OF 4PM EDT DO SHOW A FEW SCATTERED
STORMS...MAINLY SOUTH OF THE TAMPA BAY AREA AND ALONG/EAST OF THE
I-75 CORRIDOR. ALTHOUGH AN ISOLATED STORM IS POSSIBLE FOR ANYONE
THE NEXT FEW HOURS...THE BEST CHANCES INTO THE EARLY EVENING WILL
BE THE SOUTH-CENTRAL INTERIOR ZONES TO THE EAST OF THE I-75
CORRIDOR AS THE SEA-BREEZE MAKES STEADY PROGRESS INLAND FROM THE
COAST.
&&
.SHORT TERM (TONIGHT AND FRIDAY)...
UPPER TROUGH BEGINS TO DEAMPLIFY ON THE NORTHERN SIDE BY EARLY
FRIDAY AMID HEIGHT FALLS OVER THE NORTH-CENTRAL GULF COAST AND A
SIGNIFICANT VORTICITY CENTER/HEIGHT FALLS REGION WORKING DOWN
INTO THE MIDDLE MS VALLEY. THE SUBTROPICAL RIDGE AXIS WILL HAVE
SETTLED TO SOUTH FLORIDA AND THE FL STRAITS BY SUNRISE AND THEN
HOLD IN PLACE THROUGH THE DAY ON FRIDAY.
AFTER A FEW EVENING STORMS DISSIPATED WITH SUNSET...THE MAJORITY
OF THE OVERNIGHT LOOKS QUIET AND DRY WITH SEASONABLE TEMPERATURES.
LATE TONIGHT...THE COMBINATION OF SOME WEAK SYNOPTIC SUPPORT ALOFT
FROM THE INCREASING DEEP LAYER CYCLONIC FLOW...SLIGHTLY MORE
FAVORABLE LOW/MID LEVEL LAPSE RATES...AND CLIMO PREFERRED
SOUTHWEST FLOW SHOULD RESULT IN A SCATTERING OF SHOWERS/STORMS
BREAKING OUT OVER THE NORTHEAST GULF OF MEXICO. MAY SEE AN
ISOLATED STORM COME ASHORE AFTER 11-12Z AS FAR SOUTH AS CHARLOTTE
HARBOR...HOWEVER THE BEST COVERAGE AND OVERALL SHOWER POTENTIAL
LOOKS TO BE NORTH OF TAMPA BAY...AND ESPECIALLY UP TOWARD
CITRUS/LEVY COUNTIES.
SIMILAR TO WHAT OCCURRED TODAY...AS THE DAY PROGRESSES...THE
BETTER CHANCES FOR DEVELOPING STORMS WILL SHIFT FROM THE NATURE
COAST TO AREAS JUST INLAND FROM THE SUNCOAST BEACHES. THESE AREAS
SOUTH OF TAMPA BAY WILL SEE THE BEST FOCUS ALONG THE SEA-BREEZE
AND ALSO THE BETTER POTENTIAL FOR SUBSTANTIAL INSOLATION/HEATING.
NORTH OF TAMPA...AFTER THE NOCTURNAL CONVECTION FADES...MORE
ABUNDANT CLOUDS AND A SYNOPTIC FLOW AIDING SEA-BREEZE PROPAGATION
SHOULD TREND TOWARD LESS SHOWER COVERAGE DURING THE AFTERNOON
HOURS.
THE MOST NUMEROUS SHOWER ACTIVITY IN THE FORECAST PERIOD LOOKS TO
ARRIVE ACROSS THE REGION ON SATURDAY...MAKING THE FIRST HALF OF
THE UPCOMING WEEKEND LESS THAN IDEAL FOR OUTDOOR ACTIVITIES. MORE
ON THIS SETUP AND POTENTIAL IN THE LONG TERM DISCUSSION BELOW.
&&
.MID/LONG TERM (FRIDAY NIGHT - THURSDAY...A HIGHLY AMPLIFIED PATTERN
IN THE MID/UPPER LEVELS IS SETTING UP OVER THE EASTERN HALF OF THE
CONUS. A DEEPENING TROUGH EXTENDS SOUTH FROM A CLOSED LOW OVER THE
ONTARIO/QUEBEC BORDER THROUGH THE MISSISSIPPI RIVER VALLEY AND INTO
THE NORTHERN GULF OF MEXICO. THIS TROUGH MOVES EAST BY SUNDAY AND
FURTHER DEEPENS SOUTHWARD OVER THE FLORIDA PANHANDLE. BY EARLY
MONDAY MORNING...THE TROUGH LIFTS NORTHEAST AND ANOTHER CLOSED
MID/UPPER LEVEL LOW DEVELOPS OVER PENNSYLVANIA. THIS LOW CONTINUES
MOVING NORTHEAST AND RAPIDLY DEEPENS OFF THE NEW ENGLAND COAST BY
TUESDAY NEXT WEEK. AS THE UPPER LOW MOVES NORTHEAST...HIGH PRESSURE
RIDGING BUILDS INTO THE SOUTHEAST CONUS. BY LATE TUESDAY...AN UPPER
LEVEL HIGH SETS UP OVER THE FLORIDA PENINSULA AND WILL BUILD FARTHER
WESTWARD INTO THE GULF OF MEXICO THROUGH THE REMAINDER OF NEXT WEEK.
ON THE SURFACE...THE SUBTROPICAL HIGH RIDGE EAST OF FLORIDA BREAKS
DOWN AS A FRONTAL BOUNDARY EXTENDS SOUTHWEST FROM A LOW PRESSURE
CENTER OFF THE NEW ENGLAND COAST. THIS FRONT WILL SINK SOUTH OVER
NORTHERN FLORIDA AND ALONG THE NORTHERN GULF COAST. MODELS ARE IN
GOOD AGREEMENT WITH KEEPING THIS COLD FRONT PRIMARILY OVER THE
NORTHERN HALF OF FLORIDA BETWEEN THE I-10 CORRIDOR AND TAMPA BAY
THROUGH LATE SUNDAY. WEST SOUTHWEST ONSHORE FLOW AND SCATTERED TO
NUMEROUS SHOWERS AND STORMS ASSOCIATED WITH THIS FRONT WILL CONTINUE
THROUGH THE WEEKEND. THESE STORMS HAVE THE POTENTIAL FOR PRODUCING
GUSTY WINDS AND HEAVY DOWNPOURS. CONDITIONS WILL IMPROVE ON MONDAY
AS THE FRONT BEGINS TO DISSIPATE AS HIGH PRESSURE MOVES IN FROM THE
NORTH OVER TENNESSEE. DRIER CONDITIONS AND EAST SOUTHEAST WINDS WILL
RETURN TO THE FLORIDA PENINSULA. THIS WILL ALLOW FOR A MORE TYPICAL
SEA BREEZE WEATHER PATTERN TO SETUP WITH ISOLATED TO SCATTERED
AFTERNOON STORMS POSSIBLE NEXT WEEK. TEMPERATURES WILL BE A FEW
DEGREES COOLER ON SATURDAY AND SUNDAY DUE TO EXTENSIVE CLOUDINESS
AND RAINFALL...THEN WARMING BACK UP TO NORMAL NEXT WEEK.
&&
.AVIATION...
VFR CONDITIONS PREVAIL ACROSS WEST-CENTRAL AND SOUTHWEST FLORIDA
THIS AFTERNOON. SCT STORMS LIE BETWEEN KSRQ AND KFMY WITH ANY
TERMINALS BETWEEN THESE SPOTS POSSIBLY SEEING A BRIEF DOWNPOUR
THROUGH 21Z. MUCH OF THE EVENING AND OVERNIGHT WILL SEE VFR
CONDITIONS CONTINUE UNDER A SCT-BKN HIGH LEVEL CLOUD DECK. A FEW
SHOWERS WILL BE POSSIBLE FRIDAY MORNING MOVING ASHORE FROM THE
GULF...ESPECIALLY FOR KTPA/KPIE/KSRQ...HOWEVER NO SIGNIFICANT OR
EXTENDED RESTRICTIONS ARE ANTICIPATED WITH THIS ACTIVITY.
&&
.MARINE...
HIGH PRESSURE OVER THE EASTERN GULF OF MEXICO WILL PERSIST THROUGH
FRIDAY BEFORE WEAKENING AND DROPPING SOUTHWARD IN RESPONSE TO THE
APPROACH OF A FRONTAL SYSTEM FROM THE NORTH. THIS COLD FRONT IS
EXPECTED TO ARRIVE OVER THE NORTHERN GULF LATE SATURDAY AND THEN
QUICKLY WEAKEN AS IT DROPS SOUTH INTO THE DAY ON SUNDAY. HIGH
PRESSURE THEN BUILDS NORTH OF THE FORECAST WATERS BY THE EARLY
PORTION OF NEXT WEEK. A BRIEF PERIOD OF NEAR CAUTIONARY WINDS WILL
BE POSSIBLE SATURDAY NIGHT OR EARLY SUNDAY TO THE NORTH OF TAMPA
BAY...BUT OTHERWISE WINDS AND SEAS WILL REMAIN BELOW HEADLINE
CRITERIA THROUGH THE PERIOD. SCATTERED SHOWERS AND STORMS ARE
LIKELY TO BECOME MORE NUMEROUS ON SATURDAY AHEAD OF THE ADVANCING
FRONT. LOCALLY STRONGER WINDS AND ROUGH SEAS WILL BE POSSIBLE WITH
THUNDERSTORMS.
&&
.FIRE WEATHER...
SURFACE HIGH PRESSURE OVER THE STATE WILL PERSIST THROUGH THE DAY
ON FRIDAY...AND THEN BEGIN TO SETTLE SOUTHWARD AND WEAKEN IN
RESPONSE TO THE APPROACH OF A COLD FRONT FROM THE NORTH. THIS
FRONT WILL ENTER THE NORTHERN PART OF THE STATE LATE SATURDAY...
AND THEN WEAKEN QUICKLY AS IT SETTLES SOUTHWARD INTO SUNDAY. AT
THIS TIME NO SIGNIFICANT CHANGE TO A DRIER AIRMASS IS EXPECTED
WITH THIS FRONT...AND IN FACT...SOME AREAS OF LOCALLY HEAVIER
RAINFALL WILL BE POSSIBLE SATURDAY AHEAD OF THE FRONT FOR
SATURDAY. RELATIVE HUMIDITY VALUES WILL REMAIN WELL ABOVE
LEVELS THROUGH THE PERIOD.
FOG POTENTIAL...PATCHY LIGHT GROUND FOG WILL BE POSSIBLE EACH
MORNING THROUGH THE WEEKEND...HOWEVER NO SIGNIFICANT AREAS OF FOG
ARE ANTICIPATED.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 79 90 78 87 / 10 20 40 80
FMY 78 92 77 90 / 10 30 20 60
GIF 76 91 75 88 / 10 50 40 80
SRQ 78 89 77 88 / 10 30 50 80
BKV 74 90 74 87 / 10 20 40 80
SPG 80 89 78 86 / 10 20 50 80
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
SYNOPSIS/SHORT TERM/AVIATION/MARINE/FIRE WX...MROCZKA
LONG TERM/DECISION SUPPORT...WYNN
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
11 AM EDT THU SEP 10 2015
.DISCUSSION...
MORNING CAPE SOUNDING SHOWS DEEP LAYER W/SW FLOW THROUGH THE COLUMN
WITH PWAT AROUND 2 INCHES. TEMPS ALOFT REMAIN RATHER WARM...+9.5C AT
700 MB AND -6.5C AT 500 MB. UPSTREAM AT TBW...THEIR DATA SHOWS SOME
NOTICEABLY DRIER AIR (PWATS 1.79") WHICH SHOULD ADVECT INTO ECFL.
THE OFFSHORE FLOW WILL DELAY THE SEA BREEZE BUT AN ONSHORE FLOW WILL
DEVELOP SOUTH OF THE CAPE WHICH SHOULD SPARK SCT STORMS ALONG AND
JUST INLAND FROM THE COAST THIS AFTERNOON. THE PERSISTENT BAND OF
SHOWERS AND ISOLATED STORMS NW OF THE AREA EXTENDING INTO THE GULF
IS ASSOCD WITH CONVERGENCE TYPICALLY FOUND ON THE NORTH SIDE OF THE
RIDGE AXIS AND IS NOT SHOWING MUCH MOVEMENT. IT DOES NOT APPEAR TO BE
ASSOCD WITH A SFC BOUNDARY BUT OUTFLOW FROM THIS CONVECTION MAY
PROPAGATE INTO OUR NORTHERN SECTIONS THIS AFTN AND SPARK SOME ADDL
STORMS. SO THE POP DISTRIBUTION OF 30 PERCENT NORTH AND 40 PERCENT SOUTH
LOOKS GOOD AND DID NOT MAKE SIG CHANGES TO THE FCST.
TODAY-TONIGHT (PREVIOUS)...
ATLC RIDGE AXIS CENTERED OVER THE NRN BAHAMAS AND EXTENDING INTO THE
WRN GOMEX WILL INTERACT WITH A DEEP AND SLOW MOVING FRONTAL TROF
PRESSING INTO THE MID/DEEP SOUTH TO GENERATE A SWRLY BREEZE THRU THE
COLUMN ACRS CENTRAL FL. RAP ANALYSIS OF THE MOISTURE FIELDS SHOWS AN
AIRMASS SLIGHTLY ON THE DRY SIDE...MEAN RH GENERALLY AOB 70PCT THRU
THE H100-H70 LYR AND BLO 60PCT THRU THE H85-H50 LYR.
EVENING SOUNDINGS REFLECT THIS WITH PWAT VALUES BTWN 1.8"-2.0"...BUT
WITH A SUBSTANTIAL AMOUNT OF MID LVL DRY AIR: AVG DEWPOINT
DEPRESSIONS THRU THE H85-H50 LYR BTWN 7-10C DEG...WITH READINGS OVER
10C NOSING THEIR WAY UP THE I-4 CORRIDOR. MUCH OF THE MOISTURE IS
ASSOCIATED WITH A PLUME OF UPR LVL DEBRIS CLOUDS FROM CONVECTIVE
ACTIVITY OFF THE COAST OF GUATEMALA AND THE YUCATAN PENINSULA.
H85-H30 VORTICITY AND H30-H20 DIVERGENCE FIELDS REMAIN QUITE WEAK
WITH LITTLE CHANGE ANTICIPATED AS THE STRENGTH...DEPTH...AND
POSITION OF THE RIDGE WILL DEFLECT ANY ENERGY RIPPLES FROM ADVECTING
INTO THE CENTRAL PENINSULA. MID LVL TEMP PROFILE A BIT MORE UNSTABLE
THAN WED: A WEAK H70 THERMAL RIDGE REMAINS DRAPED OVER CENTRAL FL
WITH READINGS ARND 10C...H50 TEMPS ARND -6C BUT WITH POTENTIAL TO
DROP TO ARND -7C AS THE FRONTAL TROF PRESSES INTO THE THE NW FLANK
OF THE RIDGE AND SHUNTS COOLER AIR IN FROM THE NE GOMEX. INDEED...
GFS INDICATING LAPSE RATES IN THE H70-H50 LYR STEEPENING TO BTWN
6.5-7.0C/KM BY DAYBREAK.
UPR LVL DEBRIS CLOUDS WILL COMBINE WITH THE DRIER MID LVL AIR AND
WEAK DYNAMIC SUPPORT TO KEEP PRECIP CHANCES BLO 50PCT. BRISK SW FLOW
ACRS THE NRN CWA AS THE FRONTAL TROF BEGINS TO INTERACT WITH THE
ATLC RIDGE...SEA BREEZE FORMATION NOT EXPECTED FROM THE CAPE
NWD...WILL GO WITH LOWER POPS ALONG AND N OF THE I-4 CORRIDOR.
WEAKER FLOW S OF THE CAPE WILL ALLOW THE SEABREEZE TO FORM BUT WILL
KEEP IT SUPPRESSED ALONG THE I-95 CORRIDOR...WILL GO WITH HIGHER
POPS THERE...MARTIN/ST. LUCIE COUNTIES SLIGHTLY LOW TO ACCOUNT FOR
THE SHADOW EFFECT OF LAKE OKEECHOBEE. WITH LIMITED DYNAMIC
SUPPORT...PRECIP SHOULD BURN OUT SHORTLY AFT SUNSET...WILL KEEP 20
POPS ALONG THE COAST AND ARND LAKE OKEECHOBEE THRU 02Z TO ACCOUNT
FOR BLOW BACK PRECIP IN THE SW FLOW REGIME.
WARM S/SW BREEZE WILL PUSH MAX TEMPS INTO THE L/M90S...WHILE SFC
DEWPOINTS IN THE M70S SUGGEST OVERNIGHT MIN TEMPS ON THE SAME ORDER.
&&
.AVIATION...
A LIGHT W/SW FLOW WILL TURN ONSHORE (SE) AT COASTAL TERMINALS TIX SOUTH
THIS AFTERNOON. COVERAGE AGAIN LOOKS HIGHER ACROSS THE SOUTH WHERE
MOISTURE IS A BIT HIGHER SO TEMPO GROUPS LOOK OK THERE. BUT WILL REVISIT
THE NEED FOR TEMPO GROUPS ACROSS THE NORTH (MCO/SFB/DAB) WHERE LOWER
COVERAGE IS EXPECTED. WILL MAINTAIN AT LEAST VCTS.
&&
.MARINE...
NO SIGNIFICANT CHANGES TO CURRENT COASTAL WATERS FORECAST.
TODAY/TONIGHT...HI PRES RIDGE ANCHORED NE OF THE BAHAMA BANK
EXTENDING INTO THE WRN GOMEX WILL GENERATE A LIGHT TO GENTLE SWRLY
BREEZE OVER THE LCL ATLC...BCMG S/SE NEAR THE COAST S OF CAPE
CANAVERAL IN THE AFTN DUE TO THE FORMATION OF THE EAST COAST SEA
BREEZE. SEAS ARND 2-3FT. WINDS MAY FRESHEN TO A MODERATE SW BREEZE
OVER THE OFFSHORE LEG N OF SEBASTIAN INLET OVERNIGHT AS A FRONTAL
TROF PRESSES INTO THE DEEP SOUTH AND INTERACTS WITH THE RIDGE.
PRIMARY MARINE HAZARD WILL BE SCT AFTN TSTMS MOVING OFFSHORE DUE TO
THE PREVAILING S/SWRLY BREEZE...MAINLY FROM FT PIERCE INLET NWD.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 91 75 91 75 / 30 20 40 30
MCO 93 75 91 75 / 30 10 50 30
MLB 91 77 90 75 / 40 20 50 30
VRB 91 75 90 75 / 30 20 50 30
LEE 93 75 90 75 / 30 10 50 30
SFB 94 76 92 76 / 30 10 50 30
ORL 93 75 91 76 / 30 10 50 30
FPR 91 75 91 75 / 30 20 50 30
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
KELLY/PENDERGRAST
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
355 AM EDT THU SEP 10 2015
.DISCUSSION...
TODAY-TONIGHT...
ATLC RIDGE AXIS CENTERED OVER THE NRN BAHAMAS AND EXTENDING INTO THE
WRN GOMEX WILL INTERACT WITH A DEEP AND SLOW MOVING FRONTAL TROF
PRESSING INTO THE MID/DEEP SOUTH TO GENERATE A SWRLY BREEZE THRU THE
COLUMN ACRS CENTRAL FL. RAP ANALYSIS OF THE MOISTURE FIELDS SHOWS AN
AIRMASS SLIGHTLY ON THE DRY SIDE...MEAN RH GENERALLY AOB 70PCT THRU
THE H100-H70 LYR AND BLO 60PCT THRU THE H85-H50 LYR.
EVENING SOUNDINGS REFLECT THIS WITH PWAT VALUES BTWN 1.8"-2.0"...BUT
WITH A SUBSTANTIAL AMOUNT OF MID LVL DRY AIR: AVG DEWPOINT
DEPRESSIONS THRU THE H85-H50 LYR BTWN 7-10C DEG...WITH READINGS OVER
10C NOSING THEIR WAY UP THE I-4 CORRIDOR. MUCH OF THE MOISTURE IS
ASSOCIATED WITH A PLUME OF UPR LVL DEBRIS CLOUDS FROM CONVECTIVE
ACTIVITY OFF THE COAST OF GUATEMALA AND THE YUCATAN PENINSULA.
H85-H30 VORTICITY AND H30-H20 DIVERGENCE FIELDS REMAIN QUITE WEAK
WITH LITTLE CHANGE ANTICIPATED AS THE STRENGTH...DEPTH...AND
POSITION OF THE RIDGE WILL DEFLECT ANY ENERGY RIPPLES FROM ADVECTING
INTO THE CENTRAL PENINSULA. MID LVL TEMP PROFILE A BIT MORE UNSTABLE
THAN WED: A WEAK H70 THERMAL RIDGE REMAINS DRAPED OVER CENTRAL FL
WITH READINGS ARND 10C...H50 TEMPS ARND -6C BUT WITH POTENTIAL TO
DROP TO ARND -7C AS THE FRONTAL TROF PRESSES INTO THE THE NW FLANK
OF THE RIDGE AND SHUNTS COOLER AIR IN FROM THE NE GOMEX. INDEED...
GFS INDICATING LAPSE RATES IN THE H70-H50 LYR STEEPENING TO BTWN
6.5-7.0C/KM BY DAYBREAK.
UPR LVL DEBRIS CLOUDS WILL COMBINE WITH THE DRIER MID LVL AIR AND
WEAK DYNAMIC SUPPORT TO KEEP PRECIP CHANCES BLO 50PCT. BRISK SW FLOW
ACRS THE NRN CWA AS THE FRONTAL TROF BEGINS TO INTERACT WITH THE
ATLC RIDGE...SEA BREEZE FORMATION NOT EXPECTED FROM THE CAPE
NWD...WILL GO WITH LOWER POPS ALONG AND N OF THE I-4 CORRIDOR.
WEAKER FLOW S OF THE CAPE WILL ALLOW THE SEABREEZE TO FORM BUT WILL
KEEP IT SUPPRESSED ALONG THE I-95 CORRIDOR...WILL GO WITH HIGHER
POPS THERE...MARTIN/ST. LUCIE COUNTIES SLIGHTLY LOW TO ACCOUNT FOR
THE SHADOW EFFECT OF LAKE OKEECHOBEE. WITH LIMITED DYNAMIC
SUPPORT...PRECIP SHOULD BURN OUT SHORTLY AFT SUNSET...WILL KEEP 20
POPS ALONG THE COAST AND ARND LAKE OKEECHOBEE THRU 02Z TO ACCOUNT
FOR BLOW BACK PRECIP IN THE SW FLOW REGIME.
WARM S/SW BREEZE WILL PUSH MAX TEMPS INTO THE L/M90S...WHILE SFC
DEWPOINTS IN THE M70S SUGGEST OVERNIGHT MIN TEMPS ON THE SAME ORDER.
FRI/FRI NIGHT...
TROUGHING OVER THE OHIO VALLEY/EASTERN US BEGINS ITS RAPID
AMPLIFICATION DURING THE DAY...SHUNTING WHATEVER MID/UPPER LEVEL
RIDGING THAT WAS OVER THE STATE TO OUR SOUTH AND EAST. SOUTHWEST
FLOW THROUGH THE COLUMN INCREASES DURING THE DAY...EVEN AT THE
SURFACE...WHERE IT MAY PRECLUDE THE DEVELOPMENT OF THE EAST COAST
SEA BREEZE...ESPECIALLY NORTH OF THE CAPE. COOLER TEMPERATURES
ALOFT...AS LOW AS -8.5C AT 500MB...SHOULD HELP STEEPEN LAPSE RATES
AND PROVIDE A LITTLE MORE VIGOR TO AFTERNOON STORM DEVELOPMENT.
AFTERNOON CONVECTION WILL FOCUS ON THE EASTERN SIDE OF THE PENINSULA
WITH 50-60 POPS IN ORDER.
SAT-SUN...
MID/UPPER LEVEL TROUGH WILL REACH ITS MAXIMUM AMPLITUDE BY LATE
SATURDAY BEFORE CUTTING OFF EARLY SUNDAY. THE TROUGH IS EXPECTED TO
DEEPEN INTO THE NORTHERN GULF...KEEPING THE AREA UNDER DEEP CYCLONIC
FLOW WHILE PIECES OF ENERGY PASS OVERHEAD IN BRISK SOUTHWEST FLOW
ALOFT. MEANWHILE...A SURFACE BOUNDARY WILL APPROACH THE NORTHERN
PART OF THE STATE BEFORE WASHING OUT OVER CENTRAL FLORIDA EARLY
MONDAY. DESPITE AMPLE HIGH LEVEL CLOUDS STREAMING IN FROM THE
GULF...THIS RATHER ANOMALOUS SYNOPTIC SETUP SPELLS OUT HIGHER THAN
NORMAL RAIN CHANCES THIS WEEKEND.
MON-WED...
UPPER TROUGH OVER THE EAST QUICKLY LIFTS WHILE SURFACE HIGH PRESSURE
PUSHES OFF THE MID ATLANTIC. WHATEVER IS LEFT OF THE SURFACE FRONTAL
BOUNDARY WILL WASH OUT OVER THE AREA...PUTTING CENTRAL FLORIDA IN
DEEP EASTERLY FLOW FOR THE EARLY PART OF NEXT WEEK. BOTH THE
GFS/ECMWF...TO SOME EXTENT...SHOW AN OPEN WAVE / INVERTED TROUGH
PASSING OVER THE AREA TUESDAY WITH A SLIGHT UPTICK IN RAIN CHANCES
AS IT MOVES BY.
&&
.AVIATION...THRU 11/12Z
WINDS: THRU 10/14Z...S/SW ARND 3KTS. BTWN 10/14Z-10/17Z...S/SW
6-9KTS. BTWN 10/17Z-10/19Z...BCMG S/SE 7-10KTS BTWN KMLB-KSUA.
BTWN 10/23Z-11/02Z...BCMG S/SW 4-6KTS ALL SITES.
VSBY/WX/CIGS: BTWN 10/17Z-11/02Z...SCT MVFR SHRAS/IFR TSRAS ALL
SITES...SLGT CHC +TSRA WITH SFC G35KTS S OF KISM-KTIX BTWN
10/21Z-11/01Z.
&&
.MARINE...
TODAY/TONIGHT...HI PRES RIDGE ANCHORED NE OF THE BAHAMA BANK
EXTENDING INTO THE WRN GOMEX WILL GENERATE A LIGHT TO GENTLE SWRLY
BREEZE OVER THE LCL ATLC...BCMG S/SE NEAR THE COAST S OF CAPE
CANAVERAL IN THE AFTN DUE TO THE FORMATION OF THE EAST COAST SEA
BREEZE. SEAS ARND 2-3FT. WINDS MAY FRESHEN TO A MODERATE SW BREEZE
OVER THE OFFSHORE LEG N OF SEBASTIAN INLET OVERNIGHT AS A FRONTAL
TROF PRESSES INTO THE DEEP SOUTH AND INTERACTS WITH THE RIDGE.
PRIMARY MARINE HAZARD WILL BE SCT AFTN TSTMS MOVING OFFSHORE DUE TO
THE PREVAILING S/SWRLY BREEZE...MAINLY FROM FT PIERCE INLET NWD.
FRI-SUN...RIDGE AXIS REMAINS OVER SOUTH HALF OF THE PENINSULA
THROUGH THE WEEKEND...ALLOWING FOR A LIGHT TO GENTLE SOUTH TO
SOUTHWEST BREEZE OVER THE LOCAL ATLANTIC WATERS. SOUTHWEST FLOW WILL
LIMIT THE DEVELOPMENT OF THE SEA BREEZE EACH DAY...ESPECIALLY NORTH
OF THE CAPE. SEAS 1 - 2 FEET NEARSHORE AND UP TO 3 FEET WELL
OFFSHORE. PRIMARY MARINE HAZARD WILL BE AFTERNOON THUNDERSTORMS
MOVING OFFSHORE WITH A GRADUAL INCREASE IN ACTIVITY EXPECTED EACH
DAY.
MON...FRONTAL BOUNDARY WILL WASH OUT OVER CENTRAL FLORIDA...LEADING
INITIALLY TO LIGHT NORTHERLY FLOW THAT WILL VEER TO EASTERLY EARLY
NEXT WEEK AS HIGH PRESSURE PUSHES OFF THE MID ATLANTIC.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 91 75 91 75 / 30 20 40 30
MCO 93 75 91 75 / 30 10 50 30
MLB 91 77 90 75 / 40 20 50 30
VRB 91 75 90 75 / 30 20 50 30
LEE 93 75 90 75 / 30 10 50 30
SFB 94 76 92 76 / 30 10 50 30
ORL 93 75 91 76 / 30 10 50 30
FPR 91 75 91 75 / 30 20 50 30
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
SHORT TERM/AVIATION...BRAGAW
LONG TERM/IMPACT WX...ULRICH
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
807 PM EDT FRI SEP 11 2015
.UPDATE...
NEAR TERM GRIDS IN DECENT SHAPE. UPDATED POP AND WX ELEMENTS TO
BETTER REFLECT RADAR AND HIRES MODEL GUIDANCE. NOT CERTAIN THE
LINE OF SCT SHRA/TSRA WILL MAKE IT INTO ATLANTA METRO AREA...MOST
HIRES GUIDANCE /INCLUDING HRRR AND 3 LOCAL WRF MODELS/ SHOW
WEAKENING AND DECREASE IN COVERAGE AFTER 10PM. AERA OF
SNELSON
&&
.PREV DISCUSSION... /ISSUED 354 PM EDT FRI SEP 11 2015/
SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
CURRENT RADAR LOOP SHOWS A LINE OF SHOWERS AND THUNDERSTORMS
MOVING RAPIDLY SE ACROSS KY/AL/MS. THIS LINE IS ASSOCIATED WITH
THE SECOND FRONTAL BOUNDARY THAT IS EXPECTED TO MOVE INTO NW GA
LATER THIS EVENING. THIS LINE IS MOVING MUCH FASTER THAN
ORIGINALLY EXPECTED SO IT COULD BE ENTERING NW GA BY 8 TO 10PM.
WE WILL HAVE TO WATCH THIS AND ADJUST THE TIMING OF OUR FORECAST
IF IT SPEEDS UP OR SLOWS DOWN. THERE IS A BIT OF A DRIER AIRMASS
ALREADY IN PLACE ACROSS GA THIS AFTERNOON BUT THIS FRONTAL SYSTEM
WILL STILL BRING MORE MOISTURE WITH IT AS IT ENTERS THE STATE. THE
MODELS ARE ALSO SHOWING THE MAIN AREA OF DYNAMICS WITH THIS FRONT
STAYING NORTH AND EAST OF THE STATE BUT THERE WILL STILL BE SOME
INSTABILITY TO HELP SPARK SOME CONVECTION TONIGHT AND SAT MORNING.
THIS FRONT SHOULD BE SOUTH OF OUR AREA BY 20-22Z SAT WITH CLEARING
CONDITIONS RIGHT BEHIND THE FRONT. A DEVELOPING HIGH PRESSURE
RIDGE NOW OVER THE NORTHERN PLAINS BUILDS SOUTHEAST BEHIND THIS
FRONT AND BRINGS IN A MUCH DRIER AIRMASS AND COOLER TEMP. LOOKING
FOR LOW TEMPS SUNDAY MORNING IN THE UPPER 40S TO LOWER 50S ACROSS
THE NORTH GA MOUNTAINS AND NEAR 60 ACROSS CENTRAL GA. HIGH TEMPS
SUNDAY WILL BE MOSTLY IN THE 70S. WITH SOME 60S IN THE MOUNTAINS.
01
LONG TERM /SUNDAY THROUGH FRIDAY/...
CONSENSUS OF GUIDANCE HAVE RIDGING DOMINATE THRU PERIOD AND KEEP
MAJORITY OF AREA DRY. FORECAST LOOKS ON TRACK AND REFRESH OF
GUIDANCE BLEND DOES NOT DEVIATE MUCH AT ALL FROM EARLIER SOLUTION.
PREVIOUS DISCUSSION FOLLOWS...
BAKER
PREV DISCUSSION... /ISSUED 740 AM EDT FRI SEP 11 2015/
LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
EXTENDED FORECAST PERIOD STARTS WITH TEMPERATURES EXPECTED TO BE A
GOOD 10 DEGREES OR SO BELOW SEASONAL NORMALS AS AN UNUSUALLY STRONG
COLD FRONT FOR THIS TIME OF YEAR PUSHES THROUGH THE STATE. UPPER-
LEVEL PATTERN REMAINS RELATIVELY NONDESCRIPT THROUGH THE PERIOD.
SURFACE RIDGE MOVES ACROSS THROUGH THE WEEKEND REACHING THE EAST
COAST BY THE BEGINNING OF THE WORKWEEK. TEMPERATURES MODERATE BACK
TO AROUND SEASONAL NORMALS BY THE SECOND HALF OF NEXT WEEK AS WEAK
SURFACE RIDGING PERSISTS DOWN THE EAST COAST INTO THE REGION. WITH
LIMITED MOISTURE AND LITTLE OR NO SOURCE OF LIFT...THE EXTENDED
FORECAST PERIOD REMAINS BASICALLY DRY THROUGH THE WEEK AS WELL. MAY
SEE ENOUGH MOISTURE RETURN IN THE FAR SOUTH FOR SOME MINIMAL CHANCES
FOR PRECIPITATION ALONG THE SOUTHERN BORDER OF THE FORECAST AREA BY
MID TO LATE-WEEK.
20
&&
.AVIATION...
00Z UPDATE...
PRIMARY CONCERN IS LIKELIHOOD OF SHRA OR TSRA THIS EVENING AND
MVFR CIGS AFTER 09Z. LINE OF SHRA/TSRA OVER FAR NW GA COULD
AFFECT ATL METRO AIRPORTS BETWEEN 02Z-05Z WITH ISOLD SHRA
REMAINDER OF THE NIGHT AS LINE DISSIPATES. ATTM...LIKELIHOOD OF
TSRA REACHING ATL METRO NOT HIGH SO HAVE NOT INCLUDED IN FCST.
MVFR CIGS AROUND 1500FT LIKELY AFTER 09Z AND SHOULD CLEAR LATE
SAT MORNING. FINALLY WEST COMPONENT SFC WINDS WILL CONTINUE THRU
THE FCST WITH SOME GUSTS TO 20-22KT LIKELY AFTER 17Z.
//ATL CONFIDENCE...00Z UPDATE...
LOW CONFIDENCE ON TSRA DEVELOPMENT THIS EVENING.
MEDIUM CONFIDENCE ON SHRA COVERAGE AND LIKELIHOOD TONIGHT.
HIGH CONFIDENCE ON ALL OTHER ELEMENTS.
SNELSON
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 67 80 57 76 / 30 30 10 0
ATLANTA 68 78 57 73 / 30 30 10 0
BLAIRSVILLE 61 72 51 68 / 30 30 20 0
CARTERSVILLE 65 78 54 74 / 40 30 10 0
COLUMBUS 70 81 58 78 / 50 50 10 0
GAINESVILLE 67 76 56 72 / 30 30 10 0
MACON 70 83 58 78 / 50 50 20 0
ROME 65 76 54 74 / 40 20 10 0
PEACHTREE CITY 67 78 55 74 / 40 40 10 0
VIDALIA 72 83 61 80 / 50 60 30 0
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...SNELSON
LONG TERM....DEESE
AVIATION...SNELSON
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1240 PM CDT THU SEP 10 2015
.UPDATE...
ISSUED AT 1004 AM CDT THU SEP 10 2015
Outflow boundary from convection in northern Illinois showing up
nicely on regional radar mosaics, located just north of I-80 at 10
am. This may slip into the far northern CWA over the next couple
hours, although latest HRRR does not show much further south
progress. However, the actual cold front will be advancing into
southeast Iowa through midday, and the combination of this and the
remnants of the outflow will start to trigger additional shower
and thunderstorm development. PoP`s have been adjusted a bit to
time the higher chances of rain, largely keeping the rest of the
morning dry.
Little change needed to overall high temperatures, but have made
some adjustments to the hourly trends. Arrival of convection will
likely result in some falling temperatures over the far northwest
later this afternoon.
&&
.SHORT TERM...(TODAY)
ISSUED AT 330 AM CDT THU SEP 10 2015
Narrow ridge over the area is keeping clear skies across the central
and southeast parts of the CWA early this morning. Where high clouds
were last to clear last night, dense fog has developed; which is
mainly in southeast IL. Considering a dense fog advisory for about 5-
6 hours this morning. Will make last minute decision on this.
Believe this fog will likely last for a couple of hours this
morning. As the ridge moves east a frontal system will move in from
the northwest and bring the chance of showers and isolated
thunderstorms to areas northwest of a Jacksonville to Pontiac line,
mainly during the afternoon.
Cooler temps are expected today as cooler air advects into the area,
so below normal temps will occur across the whole CWA. Light winds
will become more westerly this afternoon, with wind speeds less than
10kts.
.LONG TERM...(TONIGHT THROUGH Wednesday)
ISSUED AT 330 AM CDT THU SEP 10 2015
Cold front exits southeast IL tonight with much cooler air ushering
into the region on increasing NW breezes especially by Friday
morning. A strong upper level trof digs into the area by 12Z/Fri and
will spread a good chance of showers from NW to SE across area
tonight, with southeast IL likely staying dry through this evening.
Instability parameters look weak for thunder and only carried
isolated thunder to central IL this evening and into southeast IL
overnight. Lows overnight in the upper 50s/lower 60s except near 55F
by Galesburg. Cooler highs Friday range from upper 60s NW of IL
river to mid 70s southeast of I-70 as mostly cloudy skies prevail
Friday. Chances of rain showers Friday will be mainly east of the IL
river with highest pops of 40-50% in eastern/SE IL.
Forecast models have trended stronger with upper level trof and
embedded cutoff upper level low over eastern/SE IL by Saturday
afternoon and gives isolated light rain showers in eastern IL from I-
57 east where more clouds expected. Cool highs in the mid to upper
60s on Saturday. Lows Friday night in the upper 40s/lower 50s and
then mid to upper 40s for lows Sat night.
Stronger upper level trof begins to pull east of IL across the ohio
river valley on Sunday with more sunshine expected and temps
moderating a bit with highs around 70F. Lows Sunday night mostly in
the lower 50s with eastern IL around 50F.
00Z medium and extended forecast models continue to show upper level
trof pulling away from IL during Mon-Wed time frame as upper level
ridge builds into the area and provides a stretch of dry weather.
Below normal temperatures early next week with highs Monday 75-
80F will climb to a bit above normal by Wed with highs in the 80s.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z Friday Afternoon)
ISSUED AT 1240 PM CDT THU SEP 10 2015
Outflow boundary from convection in northern Illinois is
approaching KPIA/KBMI from the north. While the ongoing convection
is expected to remain north of these TAF sites, high-res models
develop scattered convection along this boundary as it drops into
central Illinois. Already starting to see some development along
the IL/IA border west of KGBG ahead of the boundary. Have made
some adjustments to the timing of the VCTS, speeding it up by a
couple hours in most cases. The main cold front remains further
northwest and will likely start affecting central Illinois toward
06Z. After tailing off for a time, some increase in showers is
possible late tonight, but currently think the overnight thunder
potential will remain further south. Northerly winds may become
gusty toward the end of the forecast period, with cold air
advection taking place.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Geelhart
SHORT TERM...Auten
LONG TERM...07
AVIATION...Geelhart
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1013 AM CDT THU SEP 10 2015
.UPDATE...
ISSUED AT 1004 AM CDT THU SEP 10 2015
Outflow boundary from convection in northern Illinois showing up
nicely on regional radar mosaics, located just north of I-80 at 10
am. This may slip into the far northern CWA over the next couple
hours, although latest HRRR does not show much further south
progress. However, the actual cold front will be advancing into
southeast Iowa through midday, and the combination of this and the
remnants of the outflow will start to trigger additional shower
and thunderstorm development. PoP`s have been adjusted a bit to
time the higher chances of rain, largely keeping the rest of the
morning dry.
Little change needed to overall high temperatures, but have made
some adjustments to the hourly trends. Arrival of convection will
likely result in some falling temperatures over the far northwest
later this afternoon.
&&
.SHORT TERM...(TODAY)
ISSUED AT 330 AM CDT THU SEP 10 2015
Narrow ridge over the area is keeping clear skies across the central
and southeast parts of the CWA early this morning. Where high clouds
were last to clear last night, dense fog has developed; which is
mainly in southeast IL. Considering a dense fog advisory for about 5-
6 hours this morning. Will make last minute decision on this.
Believe this fog will likely last for a couple of hours this
morning. As the ridge moves east a frontal system will move in from
the northwest and bring the chance of showers and isolated
thunderstorms to areas northwest of a Jacksonville to Pontiac line,
mainly during the afternoon.
Cooler temps are expected today as cooler air advects into the area,
so below normal temps will occur across the whole CWA. Light winds
will become more westerly this afternoon, with wind speeds less than
10kts.
.LONG TERM...(TONIGHT THROUGH Wednesday)
ISSUED AT 330 AM CDT THU SEP 10 2015
Cold front exits southeast IL tonight with much cooler air ushering
into the region on increasing NW breezes especially by Friday
morning. A strong upper level trof digs into the area by 12Z/Fri and
will spread a good chance of showers from NW to SE across area
tonight, with southeast IL likely staying dry through this evening.
Instability parameters look weak for thunder and only carried
isolated thunder to central IL this evening and into southeast IL
overnight. Lows overnight in the upper 50s/lower 60s except near 55F
by Galesburg. Cooler highs Friday range from upper 60s NW of IL
river to mid 70s southeast of I-70 as mostly cloudy skies prevail
Friday. Chances of rain showers Friday will be mainly east of the IL
river with highest pops of 40-50% in eastern/SE IL.
Forecast models have trended stronger with upper level trof and
embedded cutoff upper level low over eastern/SE IL by Saturday
afternoon and gives isolated light rain showers in eastern IL from I-
57 east where more clouds expected. Cool highs in the mid to upper
60s on Saturday. Lows Friday night in the upper 40s/lower 50s and
then mid to upper 40s for lows Sat night.
Stronger upper level trof begins to pull east of IL across the ohio
river valley on Sunday with more sunshine expected and temps
moderating a bit with highs around 70F. Lows Sunday night mostly in
the lower 50s with eastern IL around 50F.
00Z medium and extended forecast models continue to show upper level
trof pulling away from IL during Mon-Wed time frame as upper level
ridge builds into the area and provides a stretch of dry weather.
Below normal temperatures early next week with highs Monday 75-
80F will climb to a bit above normal by Wed with highs in the 80s.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z Friday MORNING)
ISSUED AT 637 AM CDT THU SEP 10 2015
Besides some light fog possible at all TAF sites this morning, VFR
conditions will prevail at all sites next 24hrs. Light pcpn seen
on radar trends continues to dissipate as it move into the area
early this morning, so just expecting some high clouds this
morning at all sites, with scattered mid clouds at PIA and BMI
later this morning. As a cold front approaches the area this
afternoon, scattered clouds at around 7kft will advect over the
sites along with broken mid clouds around 15kft. Models differ on
amount of pcpn to be expected with FROPA, but will have only VCTS
at all sites with PIA first during the late afternoon and then BMI
early evening, then SPI/DEC/CMI all at 00z. Based on model timing
differences, will have VCTS for 6hrs at all sites, which results
in a mid level cig during the night around 10kft. Due to timing
and coverage differences in the models, will not have any
predominate pcpn and let later shifts fine-tune the TAFs and
things become more certain. Winds will be light ahead of the
front, and then become westerly to northwesterly with FROPA, and
then north-northwest behind the front for the afternoon and night.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Geelhart
SHORT TERM...Auten
LONG TERM...07
AVIATION...Auten
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
430 PM EDT THU SEP 10 2015
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
ISSUED AT 350 PM EDT THU SEP 10 2015
CHANCES FOR RAIN WILL INCREASE LATE TONIGHT THROUGH FRIDAY AS A COLD
FRONT MOVES THROUGH THE AREA. MUCH COOLER FALL-LIKE WEATHER WILL
FOLLOW FOR THE WEEKEND...WITH A WARMING TREND BRINGING TEMPERATURES
BACK TO NEAR NORMAL AS HIGH PRESSURE DOMINATES FOR THE FIRST HALF
OF THE WEEK.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 350 PM EDT THU SEP 10 2015
WEAK HIGH PRESSURE CONTINUES OVER THE REGION THIS AFTERNOON.
SCATTERED CONVECTION PERSISTING OVER NORTHERN ILLINOIS IN VICINITY OF
AN UPPER LEVEL WAVE. HAVE SEEN SOME CU FORMATION THIS AFTERNOON BUT
IN GENERAL...SEEING GOOD DEAL OF SUNSHINE WITH SEASONABLE TEMPS IN
THE LOWER 80S.
FOCUS OF THE NEAR TERM REMAINS ON THE APPROACHING COLD FRONT AND
UPPER WAVE WITH A GROWING CHANCE FOR RAIN SHOWERS AS THE NIGHT
PROGRESSES. INITIAL BATCH OF CONVECTION OVER NORTHERN ILLINOIS
MOVING EAST-SOUTHEAST. EXTRAPOLATION WOULD BRING THESE STORMS INTO
THE NORTHERN WABASH VALLEY BY 22-23Z. THIS ALIGNS WELL WITH HRRR AND
WRF HI-RES GUIDANCE. WITH THE AIRMASS QUITE A BIT MORE STABLE OVER
THE FORECAST AREA THOUGH...EXPECT CURRENT INTENSITY TO STORMS TO
DIMINISH CONSIDERABLY AS THEY APPROACH NORTHWEST COUNTIES...LIKELY
DISSIPATING THIS EVENING. AT THIS POINT...THIS WOULD ONLY WARRANT
LOW CHANCE POPS OVER NORTHWEST COUNTIES WITH DRY CONDITIONS
CONTINUING ELSEWHERE.
ONCE THE CONVECTION DIMINISHES...EXPECT A RELATIVELY QUIET NIGHT
WITH MOST RAIN HOLDING OFF UNTIL THE PREDAWN HOURS AS THE FRONTAL
BOUNDARY NEARS THE REGION. WILL GRADUALLY INCREASE POPS LATE TONIGHT
GENERALLY NORTHWEST OF A SULLIVAN-INDY METRO-MUNCIE LINE WITH DRY
WEATHER PERSISTING OVER THE SOUTHEAST HALF OF THE FORECAST AREA.
TEMPS...SUBTLE WARM ADVECTION AHEAD OF THE FRONT WILL KEEP TEMPS
MILD OVERNIGHT. MOS GUIDANCE MATCHED WITH LOW LEVEL THERMALS WELL
AND UTILIZED A BLEND. EXPECT LOWS RANGING FORM THE UPPER 50S TO
LOWER 60S.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
ISSUED AT 350 PM EDT THU SEP 10 2015
FORECAST CHALLENGES FOCUS ON PRECIP CHANCES THROUGH SATURDAY...ALONG
WITH TEMPS THROUGHOUT THE PERIOD.
FIRST TRUE BLAST OF FALL WEATHER POISED TO VISIT THE OHIO VALLEY
OVER THE WEEKEND AS A SHARP UPPER TROUGH POSITIONS ITSELF OVER THE
REGION. PRIOR TO THIS...WIDESPREAD RAIN SHOWERS ARE EXPECTED TO
ACCOMPANY THE COLD FRONT AS IT SWINGS ACROSS CENTRAL INDIANA ON
FRIDAY. AXIS OF LOW LEVEL CONVERGENCE COMBINED WITH DIFFLUENCE ALOFT
AND POCKETS OF ISENTROPIC LIFT ALL SUPPORT A GOOD THREAT FOR RAIN
SHOWERS...ESPECIALLY FROM LATE MORNING THROUGH THE AFTERNOON. DESPITE
WEAK INSTABILITY ON FRIDAY...FEEL ISOLATED THUNDER MENTION IS
WARRANTED WITH MODEL SOUNDINGS EXHIBITING A FEW HOURS OF STEEPER
LAPSE RATES DURING THE AFTERNOON.
QUITE POSSIBLE THAT THE GREATER CONVECTIVE THREAT COMES WITH THE
TRAILING UPPER WAVE OVER THE WESTERN GREAT LAKES WITH STORMS
DEVELOPING ON THE EDGE OF THE APPROACHING COLD POOL ALOFT. MOST OF
THIS ACTIVITY SHOULD STAY NORTHWEST OF THE FORECAST AREA PRIOR TO
FRIDAY EVENING...BUT THINK THE ARRIVAL OF THIS FEATURE COULD PROLONG
THE PRECIP THREAT OVER PARTS OF THE FORECAST AREA THROUGH MUCH OF
FRIDAY EVENING EVEN AS WHAT LITTLE INSTABILITY PRESENT DIMINISHES.
THE UPPER TROUGH WILL AMPLIFY OVER THE REGION SATURDAY AS TWO
SEPARATE VORTS DIVE INTO THE BASE OF THE TROUGH. COMBINED WITH
STRENGTHENING COLD ADVECTION AS THE COLD POOL EXPANDS SOUTH INTO
INDIANA...SATURDAY WILL HAVE A VERY AUTUMN-LIKE FEEL TO IT WITH
PLENTY OF CLOUDS AND BREEZY NORTHERLY WINDS. CANNOT RULE OUT A FEW
INSTABILITY SHOWERS AS WELL WITH THE ENERGY ALOFT SWINGING THROUGH
AND WILL MAINTAIN LOW CHANCE POPS. SKIES SHOULD GRADUALLY CLEAR
SATURDAY NIGHT AS THE UPPER TROUGH SLOWLY SHIFTS EAST AND HIGH
PRESSURE BUILDS IN FROM THE WEST. SUNDAY WILL SEE MUCH MORE IN THE
WAY OF SUNSHINE AS THE HIGH EXPANDS EAST AND SURFACE WINDS BACK TO A
MORE WESTERLY DIRECTION.
TEMPS...GENERALLY LEANED CLOSER TO COOLER MAVMOS GUIDANCE FOR FRIDAY
HIGHS WITH CLOUDS AND PRECIP IN ABUNDANCE. NEAR THE COOL END OF MOS
FOR SATURDAY AS HIGHS WILL BE ONLY IN THE 60S...AND MAY STRUGGLE TO
CLIMB OUT OF THE LOWER 60S IN SOME AREAS WHICH IS WELL SUPPORTED BY
LOW LEVEL THERMALS. TEMPS WILL BEGIN TO RECOVER ON SUNDAY AS THE
COLD POOL SHIFTS EAST...RANGING FROM THE MID 60S EAST TO NEAR 70
WEST. CHILLY NIGHTS ON THE HORIZON THROUGH THE PERIOD...HIGHLIGHTED
BY WHAT WILL LIKELY BE THE COLDEST NIGHT IN NEARLY FOUR MONTHS FOR
MANY. EXPECT LOWS IN THE 40S BOTH MORNINGS ON THE WEEKEND WITH
SUNDAY MORNING BEING THE COLDEST AS SKIES CLEAR AND WINDS DIMINISH.
UNDERCUT MOS SLIGHTLY SUNDAY MORNING AS NORMAL COOL SPOTS MAY FALL
AS LOW AS THE LOWER 40S. LOCATION OF THE HIGH CENTER TO THE WEST
HOWEVER MAY KEEP LOWER LEVELS FROM FULLY DECOUPLING AND KEEPING
TEMPS FROM COMPLETELY BOTTOMING OUT.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
ISSUED AT 229 PM EDT THU SEP 10 2015
REGIONAL INITIALIZATION LOOKS GOOD.
UPPER LEVEL RIDGING WILL MOVE INTO THE AREA SUNDAY NIGHT AND PERSIST
THROUGH WEDNESDAY...KEEPING THE WEATHER DRY. THEN TROUGHING FROM A
LOW PRESSURE SYSTEM OVER CANADA AND AN ASSOCIATED COLD FRONT WILL
APPROACH FROM THE NORTHWEST. THIS WILL BRING SLIGHT CHANCES FOR RAIN
SHOWERS AND THUNDERSTORMS BACK TO THE FORECAST WEDNESDAY
NIGHT...WITH BETTER CHANCES DURING THE DAY ON THURSDAY.
THE PERIOD WILL BEGIN WITH BELOW NORMAL TEMPERATURES IN THE UPPER
40S FOR LOWS AND LOW 70S FOR AFTERNOON HIGHS...BEFORE REBOUNDING TO
SEASONAL NORMALS AS THE RIDGE MOVES INTO PLACE. AS THE RIDGING
PERSISTS...TEMPERATURES WILL THEN INCREASE TO ABOVE SEASONAL NORMALS
FOR MID WEEK WITH HIGHS IN THE LOW 80S AND LOWS IN THE MID TO UPPER
60S.
&&
.AVIATION /DISCUSSION FOR 102100Z IND TAF UPDATE/...
ISSUED AT 430 PM EDT THU SEP 10 2015
NO CHANGES NEEDED TO THE TAF.
PREVIOUS DISCUSSION FOLLOWS...
ISSUED AT 1259 PM EDT THU SEP 10 2015
VFR EXPECTED THROUGH MOST OF THE PERIOD. SCATTERED TO BROKEN CU
ABOVE 3 KFT WILL LAST THROUGH THE DAY. A LINE OF THUNDERSTORMS
CURRENTLY OVER NORTHERN ILLINOIS COULD DEVELOP ENOUGH ON THE
SOUTHERN END AND MOVE EAST ENOUGH TO IMPACT KLAF BEFORE THEY FALL
APART THIS EVENING...BUT CONFIDENCE IN THIS IS FAIRLY LOW SO WILL
JUST INCLUDE A VCSH FOR A FEW HOURS AFTER 0Z. THEN SHOULD SEE A
BREAK UNTIL MUCH LATER DURING THE OVERNIGHT OR EVEN FRIDAY MORNING
WHEN RAIN WILL MOVE INTO THE SITES ALONG AND BEHIND THE SECONDARY
COLD FRONT. FROM FORECAST SOUNDINGS AND TIME HEIGHTS LOOKS LIKE
CEILINGS WILL BE MVFR WITH THESE SHOWERS SO WILL INTRODUCE THOSE
CONDITIONS NEAR THE END OF THE TAF PERIOD.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM...MMB/CP
AVIATION...CP/MK
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
350 PM EDT THU SEP 10 2015
.UPDATE...
THE SYNOPSIS...NEAR TERM AND SHORT TERM SECTIONS HAVE BEEN UPDATED
BELOW
&&
.SYNOPSIS...
ISSUED AT 350 PM EDT THU SEP 10 2015
CHANCES FOR RAIN WILL INCREASE LATE TONIGHT THROUGH FRIDAY AS A COLD
FRONT MOVES THROUGH THE AREA. MUCH COOLER FALL-LIKE WEATHER WILL
FOLLOW FOR THE WEEKEND...WITH A WARMING TREND BRINGING TEMPERATURES
BACK TO NEAR NORMAL AS HIGH PRESSURE DOMINATES FOR THE FIRST HALF
OF THE WEEK.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 350 PM EDT THU SEP 10 2015
WEAK HIGH PRESSURE CONTINUES OVER THE REGION THIS AFTERNOON.
SCATTERED CONVECTION PERSISTING OVER NORTHERN ILLINOIS IN VICINITY OF
AN UPPER LEVEL WAVE. HAVE SEEN SOME CU FORMATION THIS AFTERNOON BUT
IN GENERAL...SEEING GOOD DEAL OF SUNSHINE WITH SEASONABLE TEMPS IN
THE LOWER 80S.
FOCUS OF THE NEAR TERM REMAINS ON THE APPROACHING COLD FRONT AND
UPPER WAVE WITH A GROWING CHANCE FOR RAIN SHOWERS AS THE NIGHT
PROGRESSES. INITIAL BATCH OF CONVECTION OVER NORTHERN ILLINOIS
MOVING EAST-SOUTHEAST. EXTRAPOLATION WOULD BRING THESE STORMS INTO
THE NORTHERN WABASH VALLEY BY 22-23Z. THIS ALIGNS WELL WITH HRRR AND
WRF HI-RES GUIDANCE. WITH THE AIRMASS QUITE A BIT MORE STABLE OVER
THE FORECAST AREA THOUGH...EXPECT CURRENT INTENSITY TO STORMS TO
DIMINISH CONSIDERABLY AS THEY APPROACH NORTHWEST COUNTIES...LIKELY
DISSIPATING THIS EVENING. AT THIS POINT...THIS WOULD ONLY WARRANT
LOW CHANCE POPS OVER NORTHWEST COUNTIES WITH DRY CONDITIONS
CONTINUING ELSEWHERE.
ONCE THE CONVECTION DIMINISHES...EXPECT A RELATIVELY QUIET NIGHT
WITH MOST RAIN HOLDING OFF UNTIL THE PREDAWN HOURS AS THE FRONTAL
BOUNDARY NEARS THE REGION. WILL GRADUALLY INCREASE POPS LATE TONIGHT
GENERALLY NORTHWEST OF A SULLIVAN-INDY METRO-MUNCIE LINE WITH DRY
WEATHER PERSISTING OVER THE SOUTHEAST HALF OF THE FORECAST AREA.
TEMPS...SUBTLE WARM ADVECTION AHEAD OF THE FRONT WILL KEEP TEMPS
MILD OVERNIGHT. MOS GUIDANCE MATCHED WITH LOW LEVEL THERMALS WELL
AND UTILIZED A BLEND. EXPECT LOWS RANGING FORM THE UPPER 50S TO
LOWER 60S.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
ISSUED AT 350 PM EDT THU SEP 10 2015
FORECAST CHALLENGES FOCUS ON PRECIP CHANCES THROUGH SATURDAY...ALONG
WITH TEMPS THROUGHOUT THE PERIOD.
FIRST TRUE BLAST OF FALL WEATHER POISED TO VISIT THE OHIO VALLEY
OVER THE WEEKEND AS A SHARP UPPER TROUGH POSITIONS ITSELF OVER THE
REGION. PRIOR TO THIS...WIDESPREAD RAIN SHOWERS ARE EXPECTED TO
ACCOMPANY THE COLD FRONT AS IT SWINGS ACROSS CENTRAL INDIANA ON
FRIDAY. AXIS OF LOW LEVEL CONVERGENCE COMBINED WITH DIFFLUENCE ALOFT
AND POCKETS OF ISENTROPIC LIFT ALL SUPPORT A GOOD THREAT FOR RAIN
SHOWERS...ESPECIALLY FROM LATE MORNING THROUGH THE AFTERNOON. DESPITE
WEAK INSTABILITY ON FRIDAY...FEEL ISOLATED THUNDER MENTION IS
WARRANTED WITH MODEL SOUNDINGS EXHIBITING A FEW HOURS OF STEEPER
LAPSE RATES DURING THE AFTERNOON.
QUITE POSSIBLE THAT THE GREATER CONVECTIVE THREAT COMES WITH THE
TRAILING UPPER WAVE OVER THE WESTERN GREAT LAKES WITH STORMS
DEVELOPING ON THE EDGE OF THE APPROACHING COLD POOL ALOFT. MOST OF
THIS ACTIVITY SHOULD STAY NORTHWEST OF THE FORECAST AREA PRIOR TO
FRIDAY EVENING...BUT THINK THE ARRIVAL OF THIS FEATURE COULD PROLONG
THE PRECIP THREAT OVER PARTS OF THE FORECAST AREA THROUGH MUCH OF
FRIDAY EVENING EVEN AS WHAT LITTLE INSTABILITY PRESENT DIMINISHES.
THE UPPER TROUGH WILL AMPLIFY OVER THE REGION SATURDAY AS TWO
SEPARATE VORTS DIVE INTO THE BASE OF THE TROUGH. COMBINED WITH
STRENGTHENING COLD ADVECTION AS THE COLD POOL EXPANDS SOUTH INTO
INDIANA...SATURDAY WILL HAVE A VERY AUTUMN-LIKE FEEL TO IT WITH
PLENTY OF CLOUDS AND BREEZY NORTHERLY WINDS. CANNOT RULE OUT A FEW
INSTABILITY SHOWERS AS WELL WITH THE ENERGY ALOFT SWINGING THROUGH
AND WILL MAINTAIN LOW CHANCE POPS. SKIES SHOULD GRADUALLY CLEAR
SATURDAY NIGHT AS THE UPPER TROUGH SLOWLY SHIFTS EAST AND HIGH
PRESSURE BUILDS IN FROM THE WEST. SUNDAY WILL SEE MUCH MORE IN THE
WAY OF SUNSHINE AS THE HIGH EXPANDS EAST AND SURFACE WINDS BACK TO A
MORE WESTERLY DIRECTION.
TEMPS...GENERALLY LEANED CLOSER TO COOLER MAVMOS GUIDANCE FOR FRIDAY
HIGHS WITH CLOUDS AND PRECIP IN ABUNDANCE. NEAR THE COOL END OF MOS
FOR SATURDAY AS HIGHS WILL BE ONLY IN THE 60S...AND MAY STRUGGLE TO
CLIMB OUT OF THE LOWER 60S IN SOME AREAS WHICH IS WELL SUPPORTED BY
LOW LEVEL THERMALS. TEMPS WILL BEGIN TO RECOVER ON SUNDAY AS THE
COLD POOL SHIFTS EAST...RANGING FROM THE MID 60S EAST TO NEAR 70
WEST. CHILLY NIGHTS ON THE HORIZON THROUGH THE PERIOD...HIGHLIGHTED
BY WHAT WILL LIKELY BE THE COLDEST NIGHT IN NEARLY FOUR MONTHS FOR
MANY. EXPECT LOWS IN THE 40S BOTH MORNINGS ON THE WEEKEND WITH
SUNDAY MORNING BEING THE COLDEST AS SKIES CLEAR AND WINDS DIMINISH.
UNDERCUT MOS SLIGHTLY SUNDAY MORNING AS NORMAL COOL SPOTS MAY FALL
AS LOW AS THE LOWER 40S. LOCATION OF THE HIGH CENTER TO THE WEST
HOWEVER MAY KEEP LOWER LEVELS FROM FULLY DECOUPLING AND KEEPING
TEMPS FROM COMPLETELY BOTTOMING OUT.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
ISSUED AT 229 PM EDT THU SEP 10 2015
REGIONAL INITIALIZATION LOOKS GOOD.
UPPER LEVEL RIDGING WILL MOVE INTO THE AREA SUNDAY NIGHT AND PERSIST
THROUGH WEDNESDAY...KEEPING THE WEATHER DRY. THEN TROUGHING FROM A
LOW PRESSURE SYSTEM OVER CANADA AND AN ASSOCIATED COLD FRONT WILL
APPROACH FROM THE NORTHWEST. THIS WILL BRING SLIGHT CHANCES FOR RAIN
SHOWERS AND THUNDERSTORMS BACK TO THE FORECAST WEDNESDAY
NIGHT...WITH BETTER CHANCES DURING THE DAY ON THURSDAY.
THE PERIOD WILL BEGIN WITH BELOW NORMAL TEMPERATURES IN THE UPPER
40S FOR LOWS AND LOW 70S FOR AFTERNOON HIGHS...BEFORE REBOUNDING TO
SEASONAL NORMALS AS THE RIDGE MOVES INTO PLACE. AS THE RIDGING
PERSISTS...TEMPERATURES WILL THEN INCREASE TO ABOVE SEASONAL NORMALS
FOR MID WEEK WITH HIGHS IN THE LOW 80S AND LOWS IN THE MID TO UPPER
60S.
&&
.AVIATION /DISCUSSION FOR 101800Z TAF ISSUANCE/...
ISSUED AT 1259 PM EDT THU SEP 10 2015
VFR EXPECTED THROUGH MOST OF THE PERIOD. SCATTERED TO BROKEN CU
ABOVE 3 KFT WILL LAST THROUGH THE DAY. A LINE OF THUNDERSTORMS
CURRENTLY OVER NORTHERN ILLINOIS COULD DEVELOP ENOUGH ON THE
SOUTHERN END AND MOVE EAST ENOUGH TO IMPACT KLAF BEFORE THEY FALL
APART THIS EVENING...BUT CONFIDENCE IN THIS IS FAIRLY LOW SO WILL
JUST INCLUDE A VCSH FOR A FEW HOURS AFTER 0Z. THEN SHOULD SEE A
BREAK UNTIL MUCH LATER DURING THE OVERNIGHT OR EVEN FRIDAY MORNING
WHEN RAIN WILL MOVE INTO THE SITES ALONG AND BEHIND THE SECONDARY
COLD FRONT. FROM FORECAST SOUNDINGS AND TIME HEIGHTS LOOKS LIKE
CEILINGS WILL BE MVFR WITH THESE SHOWERS SO WILL INTRODUCE THOSE
CONDITIONS NEAR THE END OF THE TAF PERIOD.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM...MMB/CP
AVIATION...CP
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1233 PM CDT THU SEP 10 2015
.UPDATE...
ISSUED AT 1226 PM CDT THU SEP 10 2015
THE CONVECTION THAT DEVELOPED THIS MORNING IS STARTING TO EXIT THE
AREA. THE QUESTION NOW IS HOW QUICKLY CAN THE ATMOSPHERE RECOVER
AHEAD OF THE APPROACHING COLD FRONT. SATELLITE/OBSERVATIONS PLACES
THE COLD FRONT ROUGHLY ALONG THE MN/IA BORDER.
IF THE INTERNAL TRENDS OF THE RAP ARE CORRECT...A NEW ROUND OF
CONVECTION SHOULD BEGIN DEVELOPING DURING PEAK HEATING WITH AREAS
ALONG/SOUTH OF I-80 BEING FAVORED.
&&
.SYNOPSIS...
ISSUED AT 325 AM CDT THU SEP 10 2015
SURFACE HIGH PRESSURE RIDGE IS RETREATING TOWARD THE GREAT LAKES
AHEAD OF ADVANCING COLD FRONT FROM NORTHERN WI THROUGH SOUTHWEST
MN AND SOUTHERN SD. LIGHT SOUTHERLY RETURN FLOW ON BACKSIDE OF
DEPARTING HIGH USHERING IN MOISTURE WITH SURFACE DEWPTS CLIMBING
INTO THE LOWER 60S WEST/SOUTHWEST CWA. THIS COMBINED WITH INCREASE
IN CLOUDINESS RESPONSIBLE FOR MILDER START IN THE LOWER TO MIDDLE
60S MANY AREAS WITH FEW LOCATIONS IN THE UPPER 50S/NEAR 60 EAST OF
THE MISSISSIPPI. UPPER LEVEL DISTURBANCE PASSING TO OUR NORTH
ALONG WITH RIGHT ENTRANCE REGION OF GREAT LAKES H3 JET AIDING IN
BETTER COVERAGE OF SHOWERS AND A FEW STORMS OVER FAR NORTHEAST IA
INTO WI. MEANWHILE...MINI STORM COMPLEX OVER NORTHEAST KS
OCCURRING ON NOSE OF THETA-E ADVECTION ON 20+ KT 850-800 VEERING
WIND MAX. IN THE VERY SHORT TERM... AREA WILL BE LARGELY SPLIT BY
BOTH MECHANISMS WITH POTENTIAL FOR ISOLD-SCT SHOWERS SKIRTING
NORTHERN COUNTIES ATTENDANT TO PASSING WAVE AND UPPER
DIVERGENCE... WHILE SPRINKLES OR LIGHT SHOWER MAY OCCUR SOUTHERN
PORTIONS OF CWA BLEEDING OFF KS CONVECTIVE PROCESSES AND REMNANT
DECAYING 850-800 JET. WILL CONTINUE TO SEE CHANCES FOR SHOWERS AND
A FEW STORMS NEXT 12-18 HOURS UNTIL PASSAGE OF COLD FRONT LATER
TDY INTO THIS EVENING. THE COLD FRONT WILL BRING A FALL PREVIEW
WITH A REINFORCING SHOT OF EVEN COOLER AIR FOR FRI LINGERING INTO
THE WEEKEND.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 325 AM CDT THU SEP 10 2015
WILL CONTINUE WITH CHANCES FOR SHOWERS AND A FEW STORMS TDY TAPERING
OFF LATE PM THROUGH EVE FROM NW TO SE WITH PASSAGE OF COLD FRONT.
GENERALLY STAYED WITH PREVIOUS FORECAST OF KEEPING POPS AND QPF
BELOW GUIDANCE DUE TO A FEW CONCERNS LEADING TO UNCERTAINTY... 1)
CWA INITIALLY MOSTLY SPLIT THIS AM WITH BETTER FORCING NORTH AND
SOUTH OF CWA... 2) 850 MB FLOW SHOWN TO VEER TO WESTERLY TDY LENDING
TO DECAYING CONVERGENCE IN WAKE OF PASSING DISTURBANCE TO OUR NORTH...
NEVER A GOOD SIGN FOR ANY ORGANIZED PCPN... AND 3) CWA IS SHOWN TO
RESIDE SQUARELY IN THE UPPER JET AXIS LATER TDY AND THIS EVE AGAIN NOT
A GREAT LOCATION TO BE FOR ORGANIZED PCPN. THE RIGHT ENTRANCE REGION
OF THIS UPPER JET AND COLD FRONT THOUGH LOOK TO AID IN BLOSSOMING OF
CONVECTION LATE THIS AFTN TO OUR SOUTHWEST OVER PORTIONS OF KS...NE
POSSIBLY INTO SOUTHWEST IA AND NORTHWEST MO. STEERING FLOW FROM THE
WEST/NORTHWEST AND ORIENTATION OF MOIST AXIS SUPPORTS MOST OF THIS
ACTIVITY SCOOTING JUST SOUTH OF CWA. OVERALL... ATTIM LOOKS LIKE JUST
SPOTTY PRECIP TDY INTO THIS EVE.
AS FOR TEMPS... HIGHS TDY WILL BE CHALLENGING WITH TEMPS MODULATED
BY THE CLOUDS AND ANY PRECIP AND EVAPORATIONAL COOLING FROM THE
PRECIP PROCESSES. AREAS THAT SEE ANY FILTERED SUNSHINE SHOULD SEE
HIGHS AROUND 80... WHILE AREAS THAT REMAIN CLOUDY SHOULD SEE HIGHS
ONLY IN THE LOWER TO MIDDLE 70S. MUCH COOLER LOWS TONIGHT POST-FRONTAL
WITH UPPER 40S NORTH TO UPPER 50S SOUTH...AND WOULD NOT BE SURPRISED
IF THESE NEED TO BE LOWERED 1-3 DEGS BASED ON VERIFICATION OF
MODEL TEMPS AND OBS EARLY THIS AM. THE COOLER AIR WILL BE USHERED
IN ON GUSTY NORTH WINDS OF 10-20 MPH. SHOULD ALSO SEE GRADUAL
CLEARING NW OVERNIGHT SPREADING SE.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 325 AM CDT THU SEP 10 2015
FORECAST FOCUS ON VERY COOL TEMPERATURES THROUGH THIS WEEKEND THEN A
WARM-UP FOR THE FIRST HALF OF NEXT WEEK. MAINLY A DRY PERIOD ALSO.
FRIDAY...MUCH COOLER IN THE WAKE OF THE COLD FRONT THAT WOULD HAVE
ALREADY EXITED THE DVN CWA. COLD AIR ADVECTION WILL PRODUCE SOME
OCCASIONAL LOW CLOUDS ALONG WITH GUSTY NORTH WINDS TO 20 TO 25 MPH.
THIS WILL MAKE FOR A VERY COOL DAY WITH MAXIMUM TEMPERATURES IN THE
MID TO UPPER 60S AT MOST LOCATIONS.
FRIDAY NIGHT THROUGH SUNDAY...DELIGHTFUL AUTUMN-LIKE WEATHER IS IN
STORE AS DEEP UPPER LEVEL TROUGH SHIFTS SLOWLY EASTWARD AND SURFACE
HIGH PRESSURE BUILDS INTO THE AREA. MAINLY CLEAR SKIES EXPECTED
THROUGH THE WEEKEND. HIGHS WILL BE IN THE MID 60S SATURDAY AND
AROUND 70 ON SUNDAY. LOWS SHOULD BOTTOM OUT IN THE 40S AT MOST
LOCATIONS. THERE IS STILL THE POTENTIAL OVER THE WEEKEND FOR A FEW
FAVORED VALLEY/SHELTERED LOCATIONS TO DIP INTO THE UPPER 30S WHERE
WINDS CAN REMAIN CALM FOR SEVERAL HOURS.
MONDAY THROUGH WEDNESDAY...A DRAMATIC WARM-UP AS THE TROUGH IN THE
EAST LIFTS WELL TO THE NORTHEAST ONLY TO BE REPLACED BY ANOTHER DEEP
TROUGH...BUT THIS TIME IN THE WESTERN UNITED STATES. THE UPPER LEVEL
FLOW WILL BECOME SOUTHWEST ACROSS THE MIDWEST ALLOWING FOR MUCH
WARMER TEMPERATURES FOR THE FIRST HALF THE WEEK. WITH RIDGING ALONG
THE GULF COAST THIS WILL PREVENT THE GULF MOISTURE FROM RETURNING
NORTHWARD. HIGHS WILL BE WARMING WELL INTO THE 70S ON MONDAY AND IN
THE LOWER TO MID 80S TUESDAY AND WEDNESDAY. DEPENDING ON CLOUD
TRENDS AND IF DEEPER MIXING CAN OCCUR THEN READINGS MAY APPROACH 90
IN OUR NW CWA...WITH 850 MB TEMPERATURES PROGGED TO 20C.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1226 PM CDT THU SEP 10 2015
INITIAL CONVECTION IS MOVING INTO NORTHERN ILLINOIS WITH THE
EXCEPTION OF SOME CONVECTION APPROACHING KDBQ. THERE ARE QUESTIONS
ON HOW CONVECTION WILL DEVELOP/EVOLVE THIS AFTERNOON WHICH IS
TIED TO HOW QUICKLY THE ATMOSPHERE CAN RECOVER. MAINLY VFR
CONDITIONS ARE EXPECTED THROUGH 01Z/11. IF A SHRA OR TSRA AFFECTS
A TAF SITE...A BRIEF PERIOD OF MVFR OR EVEN IFR CONDITIONS IS
VERY POSSIBLE. AFT 01Z/11 VFR CONDITIONS ARE EXPECTED AS HIGH
PRESSURE BUILDS INTO THE MIDWEST.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...08
SYNOPSIS...05
SHORT TERM...05
LONG TERM...HAASE
AVIATION...08
AREA FORECAST DISCUSSION
National Weather Service Dodge City KS
606 AM CDT THU SEP 10 2015
...Updated aviation discussion...
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 121 AM CDT THU SEP 10 2015
Short range models indicate an upper level shortwave digging
southeastward across the Northern Plains into the Upper Midwest late
today. Meanwhile, an attendant cold front is projected to push
slowly southward into northwest and north central Kansas late this
afternoon. Although the flow aloft is expected to be less than
robust across western Kansas, ample moisture pooling ahead of the
approaching frontal boundary will provide plenty of instability with
SBCAPE values rising in excess of 2000 J/KG by this afternoon. Along
with increasingly more favorable vertical shear profiles developing
through the afternoon period, thunderstorm development will be
possible in the vicinity of the frontal boundary through Thursday
night as it moves further south into Oklahoma. A few storms could
become severe.
Above normal temperatures are likely today as a prevailing southerly
flow draws warmer air northward into the area. Highs pushing into
the lower to mid 90s(F) can be expected late this afternoon in
locations ahead of the approaching frontal boundary. Lows are
expected to be down into the 50s(F) and 60s(F) tonight as cooler air
filters southward into western Kansas behind the frontal boundary.
.LONG TERM...(Friday THROUGH Wednesday)
ISSUED AT 224 AM CDT THU SEP 10 2015
Drier conditions are likely through the weekend as medium
range models indicate a weak flow aloft associated with a ridge
of high pressure moving eastward across the Intermountain West
into the Western High Plains during the period. Meanwhile, a
significant drop in temperatures is likely Friday as much cooler
air filters southward into western Kansas in wake of a cold
frontal passage late Thursday. The GFS and ECMWF show H85
temperatures falling well down into the Teens(C) by late Friday.
Look for highs only up into the 70s(F) for the most part Friday
afternoon. A gradual warming trend is then expected with highs
back up into the 90s(F) early next week as the aforementioned
upper level ridging moves out of the Central Rockies into the
high plains.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z Friday MORNING)
ISSUED AT 603 AM CDT THU SEP 10 2015
Early morning convection will taper off from north to south
through 15z as one upper level disturbance crosses western Kansas.
The chance for thunderstorms will then return after 18z as a cold
front moves south across western Kansas during the afternoon and
early evening. At this time it appears the better chances for
afternoon thunderstorms will be at Hays and Dodge City with these
storms shifting south and east of these airports by or shortly
after sunset. 06z BUFR soundings along with the latest RAP and
HRRR all indicating mainly low VFR ceilings with these storms
later this afternoon. Southerly winds ahead of the cold front will
shift to the northeast as the cold front passes late today and
early tonight. In addition to the wind shift the 06z NAM along
with the RAP indicated some low level moisture will begin to
return to western Kansas behind the cold front. At this time will
trend towards MVFR conditions behind the cold front after 03z
Friday.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 92 59 75 54 / 40 50 20 0
GCK 90 58 76 55 / 20 20 20 0
EHA 92 59 75 56 / 10 20 20 10
LBL 92 60 76 56 / 40 50 20 10
HYS 90 57 75 52 / 30 40 20 0
P28 92 63 78 55 / 60 60 20 0
&&
.DDC Watches/Warnings/Advisories...
NONE.
&&
$$
SHORT TERM...JJohnson
LONG TERM...JJohnson
AVIATION...Burgert
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1251 AM EDT THU SEP 10 2015
...UPDATED AVIATION DISCUSSION...
...FORECAST UPDATE...
ISSUED AT 955 PM EDT WED SEP 9 2015
SURFACE COLD FRONT AT 01Z WAS DRAPED ROUGHLY E-W OR NE-SW ACROSS
CENTRAL KY, ALTHOUGH EXACT POSITION A BIT DIFFICULT TO TELL, LIKELY
NEAR AN AXIS OF NEAR CALM WIND FROM LEX TO BWG. THERE ALSO APPEARED
TO BE A WEAK AREA OF LOW PRESSURE ROUGHLY NEAR THE SW KY/NW TN
BORDER ALONG THE BOUNDARY. AHEAD OF THIS LOW, RADAR SHOWED AN AREA
OF RAIN AND EMBEDDED STORMS OVER CENTRAL KY, ESPECIALLY BUTLER,
GRAYSON, AND EDMONSON COUNTIES AT 0145Z. IN FACT, RADAR LOOP
SUGGESTS A BROAD CIRCULATION ASSOCIATED WITH THE AREA OF RAIN.
EXPECT THE RAIN AND EMBEDDED CONVECTION TO PUSH ENE LATE THIS
EVENING INTO THE OVERNIGHT PERIOD WITH THE MESOSCALE SHORTWAVE
PROVIDING FORCING FOR LIFT. OCCASIONAL HEAVY RAIN MAY CONTINUE
ASSOCIATED WITH THIS FEATURE.
ELSEWHERE, WITH A BROAD SW-NE-ORIENTED MID-UPPER LEVEL MOISTURE
PLUME OVER THE OH AND TN VALLEYS AS SHOWN IN WATER VAPOR IMAGERY,
AND WITH THE WEAK SURFACE BOUNDARY/LOW IN THE VICINITY, SCATTERED
SHOWERS ARE EXPECTED OVER MUCH OF THE REMAINDER OF CENTRAL KY
OVERNIGHT, WITH THE BEST COVERAGE OVER SOUTHERN/EASTERN COUNTIES.
THERE SHOULD BE LITTLE PRECIP OVER MOST OF SOUTH-CENTRAL IN.
LATEST DATA SUGGESTS FOG MAY NOT BE AS MUCH OF A PROBLEM TOWARD
MORNING AS EARLIER EXPECTED, BUT STILL AREAS OF FOG AND LOWER CLOUDS
ARE EXPECTED AND RETAINED IN THE FORECAST. NO SIGNIFICANT CHANGES TO
TEMPS NEEDED OVERNIGHT FROM ONGOING FORECAST.
.SHORT TERM (NOW THROUGH THURSDAY NIGHT)...
ISSUED AT 245 PM EDT WED SEP 9 2015
AS OF MID AFTERNOON...WATER VAPOR IMAGERY AND 500 MB HEIGHTS SHOWED
A SHORTWAVE TROUGH EXTENDING FROM THE GREAT LAKES DOWN ALONG THE
MISSISSIPPI RIVER...JUST WEST OF CENTRAL KENTUCKY. AT THE
SURFACE...THE ENVIORNMENT IS CHARACTERIZED BY WARM AND MOIST AIR
WITH DEWPOINTS IN THE LOW 70S. A COLD FRONT LIED ALONG THE OHIO
RIVER...SLOWLY MOVING EAST THROUGH THE AREA.
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS MAINLY IN THE WARM
SECTOR WILL CONTINUE THROUGH THE LATE AFTERNOON HOURS. THESE STORMS
WILL BE CAPABLE OF PROUDCING BRIEF BUT VERY HEAVY RAINFALL GIVEN THE
HIGH PWATS IN THE AREA. SOME GUSTY WINDS ARE POSSIBLE AS WELL.
HI-RES MODELS SUCH AS THE HRRR AND 12Z SPC WRF ARE IN GOOD AGREEMENT
SHOWING THE HIGHEST CHANCES NOW THROUGH EARLY EVENING...THEN A
DECREASE IN COVERAGE AS THE UPPER SHORTWAVE TROUGH KICKS THE FRONT
EAST THROUGH THE AREA. A SECONDARY LOW PRESSURE AND TROUGH NEAR
MEMPHIS WILL TRACK THROUGH CENTRAL TN TO SOUTHEAST KY
OVERNIGHT...KEEPING SOME SHOWERS AND STORMS IN THE FORECAST MAINLY
OVERNIGHT FOR THE SOUTHERN FORECAST AREA. AREAS NORTH OF THE KY
PARKWAYS INTO SOUTHERN INDIANA WILL PROBABLY SEE THE END OF THE RAIN
FROM THIS SYSTEM THIS EVENING OR EARLY OVERNIGHT.
LOW CLOUDS AND/OR FOG IS A CONCERN OVERNIGHT INTO THE THURSDAY
MORNING COMMUTE AS THE BOUNDARY LAYER WILL REMAIN VERY MOIST WITH
LIGHT WINDS. SREF PROBABIALITIES FOR LOW CLOUDS /500 FT OR LESS/ AND
FOG ARE BETWEEN 40 AND 60 PERCENT. WILL HAVE TO WATCH FOR LOCALLY
DENSE POCKETS OF FOG...ESPECIALLY IF THERE IS ANY CLEARING OR BREAKS
IN THE CLOUDS TOWARD SUNRISE.
IMPROVING CONDITIONS CAN BE EXPECTED DURING THE DAY THURSDAY. SOME
LINGERING SHOWERS AND MAYBE A THUNDERSTORM WILL BE POSSIBLE ALONG
AND SOUTHEAST OF A LEXINGTON TO BOWLNG GREEN LINE DURING THE MORNING
BUT THIS SHOULD QUICKLY MOVE EAST BY NOON. NORTHWEST WINDS WILL PICK
UP...HELPING TO SCATTER OUT OR LIFT SOME OF THE CLOUDS IN THE
AREA. LOOK FOR HIGHS RIGHT AROUND NORMAL IN THE LOW 80S.
.LONG TERM (FRIDAY THROUGH WEDNESDAY)...
ISSUED AT 305 PM EDT WED SEP 9 2015
THE LONG TERM PERIOD WILL START OUT WITH A COLD FRONT PASSAGE ON
FRIDAY BRINGING SHOWERS/STORMS TO THE AREA FRI/FRI NIGHT. ALTHOUGH
THE OVERALL FORCING NEAR THE FRONT AND WIND SHEAR LOOK RELATIVELY
WEAK, THERE MAY BE ENOUGH SFC INSTABILITY TO PRODUCE A FEW STRONG
CELLS DURING THE AFTERNOON HOURS FRIDAY. OVERALL THOUGH, DON`T SEE
A BIG THREAT FOR ORGANIZED STRONG TO SEVERE CONVECTION FOR FRIDAY.
THE BIGGER STORY WITH THIS FRONT WILL BE THE STRONG UPPER LOW AND
MUCH COOLER AIRMASS FOLLOWING IT. WITH THESE FEATURES IN PLACE FOR
THE WEEKEND, LOOK FOR TEMPS TO BE 6 TO 12 DEGREES BELOW NORMAL.
SATURDAY WE`LL HAVE PLENTY OF LOW CLOUDS AND LINGERING SHOWERS
LIMITING HIGHS TO THE MID TO UPPER 60S. SOME MODEL DATA SUGGESTS
PERHAPS WE COULD SEE AN ISLD RUMBLE OF THUNDER WITH THIN, SHALLOW
INSTABILITY PRESENT IN THE SOUNDINGS. SHOWER ACTIVITY SHOULD
CONTINUE INTO SAT NIGHT BEFORE GRADUALLY ENDING FROM WEST TO EAST
SUN MORNING. HIGHS ON SUNDAY WILL BE SIMILAR TO SAT IN THE MID TO
UPPER 60S. LOW TEMPERATURES THIS WEEKEND WILL RANGE FROM THE MID
40S TO LOWER 50S WITH THE COOLEST NIGHT BEING SUN NIGHT INTO MONDAY
MORNING WHEN SKIES WILL BECOME CLEAR WITH THE HIGH PRESSURE CENTER
OVER THE REGION.
WE`LL REMAIN DRY MON-WED WITH RETURN FLOW BRINGING WARMER TEMPS BACK
INTO THE REGION. HIGHS ON MONDAY WILL WARM BACK INTO THE LOWER 70S
WITH UPPER 70S/LOWER 80S EXPECTED BY TUES/WED UNDER MOSTLY SUNNY
SKIES.
&&
.AVIATION (06Z TAF UPDATE)...
ISSUED AT 1250 AM EDT THU SEP 10 2015
SCATTERED SHOWERS CONTINUE TO MOVE ACROSS CENTRAL KENTUCKY TONIGHT.
THE BEST CHANCES FOR SHOWERS WILL SHIFT EAST THROUGH THE REMAINDER
OF THE NIGHT AND INTO TOMORROW MORNING. WILL THEREFORE CARRY VCSH AT
LEX FOR THE LONGEST, INTO THE DAYLIGHT HOURS.
FOG AND LOW CEILINGS WILL BECOME A CONCERN THIS MORNING WITH AMPLE
LOW LEVEL MOISTURE AND LIGHT WINDS. GUIDANCE SUGGEST CONDITIONS WILL
BE THE WORST AT BWG WHERE IFR (POSSIBLY LOWER) CEILINGS LOOK TO
DEVELOP THIS MORNING. WILL KEEP THE FORECAST MORE OPTIMISTIC AT SDF
AND LEX WITH JUST MVFR CEILINGS. HOWEVER, WILL HAVE TO WATCH THESE
CLOSELY.
WINDS WILL BE LIGHT AND VARIABLE TO CALM TONIGHT AND OUT OF THE
NORTH THROUGH THE DAY. CONDITIONS SHOULD IMPROVE TO VFR AT ALL SITES
BY LATE MORNING TO EARLY AFTERNOON.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
UPDATE.........TWF
SHORT TERM.....ZBT
LONG TERM......AMS
AVIATION.......EER
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
234 PM CDT THU SEP 10 2015
.DISCUSSION...
FRONTAL BOUNDARY CONTINUES TO BE VERY DIFFUSE LATE THIS AFTERNOON
BUT THE LOWER DEWPOINTS ACROSS NORTHERN LOUISIANA SUGGESTS THAT
PERHAPS THE BOUNDARY HAS MIXED A LITTLE SOUTH OF THE I-20 CORRIDOR
ATTM. SHOWERY CONVECTION FOR THE MOST PART HAS BEEN CONFINED TO
AREAS SOUTH OF THE I-20 CORRIDOR...OR ACROSS DEEP EAST TEXAS INTO
PORTIONS OF WEST CENTRAL AND EAST CENTRAL LA. FOR TONIGHT... HAVE
MAINTAINED CHANCE POPS ACROSS OUR SOUTHERN ZONES WITH SLIGHT
CHANCE POPS COVERING THE I-20 CORRIDOR JUST IN CASE SOMETHING WERE
TO IGNITE ALONG THE FRONT WHICH THE 12Z NAM STILL SUGGESTS MIGHT
HAPPEN EVEN THOUGH THE HRRR HAS BACKED OFF THIS SCENARIO.
THIS BOUNDARY WILL CONTINUE TO SERVE AS A FOCUS FOR CONVECTION
DURING THE DAY FRIDAY AND GIVEN THE STEEP MID LEVEL LAPSE RATES
AND MODERATE INSTABILITY EXPECTED SOUTH OF THE CORRIDOR ON
FRIDAY...CANNOT RULE OUT AN ISOLATED STRONG TO SEVERE STORM
OR TWO DURING PEAK HEATING. IN ADDITION...SHORTWAVE ENERGY
DROPPING QUICKLY OUT OF THE CENTRAL PLAINS INTO THE SOUTHERN
PLAINS/MID MISS VALLEY WILL PROVIDE THE UPPER LEVEL SUPPORT
NECESSARY FOR INCREASING SHOWERS AND THUNDERSTORMS MOVING INTO OUR
REGION FROM THE NORTHWEST. THIS WILL BE THE LEADING EDGE OF THE
MUCH COOLER AND DRIER WEATHER FORECAST FOR THE UPCOMING WEEKEND.
THE I-20 CORRIDOR WILL LIKELY ENCOUNTER THIS FRONTAL FORCING BY
LATE AFTERNOON/EARLY EVENING...THUS THE POSSIBILITY OF A STRONG
STORM LATE IN THE DAY. KEPT POPS AT HIGH END CHANCE CATEGORY FOR
FRIDAY EVENING WITH THE CONVECTION LIKELY DISSIPATING AFTER
MIDNIGHT WITH THE COOLER/DRIER AIR FOLLOWING FROM THE NORTH.
COULD SEE TEMPERATURES IN THE UPPER 50S FOR LOWS SATURDAY MORNING
WITH HIGHS ON SATURDAY RANGING IN THE 80S WITH MUCH DRIER
DEWPOINTS. THE COOLEST MORNING SHOULD BE SUNDAY WITH WIDESPREAD
50S AREAWIDE AND I WOULD NOT BE SURPRISED TO SEE UPPER 40S ACROSS
OUR MOST PROTECTED NORTHERN ZONES. RECORDS MAY FALL IF THIS
OCCURS.
TEMPERATURES SHOULD BEGIN TO MODERATE BY THE FIRST OF NEXT WEEK AS
WE SEE RETURNING SOUTHERLY FLOW SETTING UP. ALOFT...WE WILL
TRANSITION FROM A NORTHERLY FLOW...TO ZONAL...AND EVENTUAL
SOUTHWEST FLOW AS THE NEXT LONGWAVE TROUGH MOVES ONSHORE THE
PACIFIC NORTHWEST. WITH UPPER RIDGING FCST TO SETUP ACROSS THE MID
ATLANTIC BY THE MIDDLE PART OF NEXT WEEK...WE SHOULD BEGIN TO SEE
AT LEAST WIDELY SCATTERED AFTERNOON/EVENING VARIETY CONVECTION
WITH A RETURN TO NEAR NORMAL TEMPERATURES.
PRELIMS TO FOLLOW...13.
&&
.PREV DISCUSSION... /ISSUED 1254 PM CDT THU SEP 10 2015/
AVIATION...
FOR THE 10/18Z TAFS...A QUASI-STATIONARY COLD FRONT IS LOCATED
ROUGHLY PARALLEL TO AND JUST NORTH OF I-20. ISOLATED TO WIDELY
SCATTERED CONVECTION IS QUICKLY DEVELOPING SOUTH OF THE FRONT.
SHWRS/TSTMS WILL LIKELY AFFECT LOCATIONS ALONG AND SOUTH OF I-20.
DID NOT INCLUDE A MENTION OF PRECIP AT KSHV AS DEVELOPMENT IS MORE
UNCERTAIN BUT WILL MONITOR CLOSELY. SHWRS/TSTMS SHOULD GRADUALLY
DISSIPATE AFTER 11/00Z. MVFR/IFR CIGS/VSBYS ARE EXPECTED TO ONCE
AGAIN DEVELOP ACROSS MOST OF THE AREA DURING THE OVERNIGHT/EARLY
MORNING HRS. WHILE THIS FIRST COLD FRONT DISSIPATES...A SECOND
FRONT WILL MOVE INTO THE AREA DURING THE DAY FRIDAY. MORE PRECIP
IS POSSIBLE AHEAD OF THIS NEXT FRONT SOUTH OF I-20. /09/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 73 92 65 84 / 20 30 50 10
MLU 70 92 66 84 / 20 20 50 10
DEQ 66 89 58 81 / 10 40 20 0
TXK 69 91 61 81 / 10 30 40 0
ELD 66 90 60 79 / 10 30 40 0
TYR 73 92 65 84 / 20 30 50 10
GGG 71 92 65 83 / 20 30 50 10
LFK 73 92 69 87 / 30 30 50 10
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
LA...NONE.
OK...NONE.
TX...NONE.
&&
$$
09/13
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
321 PM EDT THU SEP 10 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 505 AM EDT THU SEP 10 2015
WATER VAPOR IMAGERY AND RAP ANALYSIS SHOW A TROF EXTENDING S INTO
THE NCNTRL STATES AND UPPER GREAT LAKES...ANCHORED BY A MID LEVEL
LOW OVER NRN ONTARIO. SHORTWAVE MOVING ACROSS NRN ONTARIO IS HELPING
TO DRIVE A COLD FRONT SE...CURRENTLY ACROSS WRN LAKE SUPERIOR. DEEP
LAYER FORCING PER QVECTORS IS SUPPORTING AN AREA OF SHRA MOVING
ACROSS NE WI INTO SCNTRL UPPER MI EARLY THIS MORNING. ISOLD SHRA
HAVE BEEN OCCURRING FARTHER N TO LAKE SUPERIOR. EVEN A TSTM WAS
NOTED OVER ERN LAKE SUPERIOR A FEW HRS AGO.
AS FORCING SUPPORTING THE NE WI PCPN SHIFTS E...THIS MORE ORGANIZED
SHRA AREA WILL MOVE ACROSS THE SCNTRL AND PORTIONS OF THE ERN FCST
AREA OVER THE NEXT FEW HRS. THIS MAIN AREA OF PCPN SHOULD BE E OF
THE AREA NO LATER THAN MID MORNING. WITH COLD FRONT STILL PUSHING
SE...POTENTIAL IS THERE FOR ADDITIONAL ISOLD TO SCT SHRA DEVELOPMENT
UNTIL FROPA. THIS POTENTIAL SHOULD INCREASE DURING THE AFTN AS SOME
INSTABILITY BUILDS UP AHEAD OF COLD FRONT. DEVELOPING LAKE BREEZE
OFF LAKE MICHIGAN WILL ALSO STRENGTHEN THE LOW-LEVEL CONVERGENCE
ALONG THE SE MOVING COLD FRONT. RAP AND GFS SHOW MLCAPES UPWARDS OF
200-300J/KG OVER THE SCNTRL/SE FCST AREA. 00Z NAM SHOWED MLCAPE OVER
1000J/KG. WHILE THE 06Z NAM HAS PULLED BACK TO 600-800J/KG...IT
STILL LOOKS OVERDONE. IN ANY EVENT...THE AVBL INSTABILITY SUGGESTS
THE POTENTIAL FOR ISOLD TSTMS OVER THE SCNTRL/SE FCST AREA THIS AFTN
ALONG/AHEAD OF COLD FRONT.
CAA TODAY/TONIGHT WILL DROP 850MB TEMPS DOWN TO 0 TO 2C OVER LAKE
SUPERIOR BY 12Z FRI...SUFFICIENT FOR LAKE EFFECT PROCESSES WITH
WATER TEMPS ROUGHLY 15-18C. WITH NAM/GFS FCST SOUNDINGS SHOWING A
WELL MIXED LAYER IN LOWER 2KFT OF THE AIR MASS...BELIEVE IT WILL
TAKE SOME TIME TO GET LAKE EFFECT GOING TONIGHT...ESPECIALLY IN
LIGHT OF THE LACK OF SYNOPTIC SUPPORT WITH DEEP LAYER QVECTOR
DIVERGENCE DOMINATING. NOT EXPECTING ANYTHING MORE THAN ISOLD TO
PERHAPS SCT -SHRA COVERAGE. WITH WATER TEMPS MORE IN THE 12-15C
RANGE OVER THE ERN LAKE...-SHRA COVERAGE WILL BE LEAST OVER THE ERN
FCST AREA. IN FACT...THERE MAY NOT BE ANY LAKE EFFECT -SHRA OVER THE
FAR E TONIGHT.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 319 PM EDT THU SEP 10 2015
THE LONG TERM FORECAST WILL START ON THE COOL SIDE...BUT
TEMPERATURES WILL MODERATE FOR THE SECOND HALF OF THE WEEKEND AND
BE ABOVE NORMAL FOR MOST OF NEXT WEEK. THE PERIOD OF BELOW NORMAL
TEMPERATURES OVER THE GREAT LAKES REGION WILL BE TIED TO THE UPPER
TROUGH THAT WILL BE OVER THE AREA AT THE START OF THE PERIOD.
TEMPERATURES ALOFT (850MB VALUES AROUND 1-2C) WILL BE FAVORABLE FOR
AT LEAST LAKE CLOUDS FRIDAY NIGHT INTO SATURDAY...BUT THE MAIN
CONCERN IS FOR THE AMOUNT OF LOW LEVEL MOISTURE AVAILABLE TO PRODUCE
CLOUDS. THE NAM CONTINUES TO SHOW ABUNDANT LOW LEVEL MOISTURE AND
HOLDS ON TO LAKE EFFECT CLOUDS FOR THE FAVORED NORTHERLY WIND
UPSLOPE LOCATIONS ON FRIDAY NIGHT AND THEN EXPANDS IT ACROSS THE
REST OF THE U.P. WITH DIURNAL HEATING ON SATURDAY. THE OTHER MODELS
ARE NOT AS EXCITED ABOUT THE LOW LEVEL MOISTURE WITH THE SURFACE
RIDGE MOVING INTO THE AREA. AT THIS POINT...WILL GO WITH PARTLY
CLOUDY SKIES FOR FRIDAY NIGHT (ESPECIALLY IN THE NORTHERLY UPSLOPE
AREAS) AND GRADUALLY DIMINISH THROUGH THE DAY ON SATURDAY.
UNFORTUNATELY...THAT DOES CREATE SOME QUESTION MARKS ON LOWS FOR
FRIDAY NIGHT AND IN TURN FROST POTENTIAL. THINK THERE WILL BE
ENOUGH GAPS IN THE CLOUDS OVER THE INTERIOR WEST THIRD OF THE U.P.
TO HAVE DECENT RADIATIONAL COOLING WITH THE DECOUPLING WINDS AND
HAVE CONTINUED TO SHOW LOWS IN THE MID 30S AND PATCHY FROST THERE.
THE HIGH PRESSURE RIDGE WILL MOVE OVER THE AREA SATURDAY
AFTERNOON/EVENING AND BRING CLEAR SKIES TO THE AREA. WITH THE CLEAR
SKIES AND LIGHT WINDS...EXPECT MUCH OF THE INTERIOR U.P. TO SEE
LOWS FALLING INTO THE 30S. WILL SHOW A LITTLE MORE COVERAGE OF THE
PATCHY FROST OVER THE WEST/CENTRAL AND INTO PARTS OF THE
EAST...ALTHOUGH THE WEST WILL LIKELY SEE RETURN FLOW DEVELOPING
DURING THE OVERNIGHT HOURS AND RAISE TEMPERATURES SLIGHTLY TOWARDS
MORNING.
SOUTHWESTERLY FLOW WILL CONTINUE SUNDAY AND THROUGH MUCH OF NEXT
WEEK AS A LOW MOVES THROUGH CENTRAL CANADA ON SUNDAY AND THEN
ANOTHER LOW TAKES SHAPE UNDER THE DEVELOPING UPPER TROUGH OVER THE
NORTHWESTERN CONUS EARLY NEXT WEEK. THE FIRST LOW WILL TRY TO DRAG
A COLD FRONT TOWARDS THE AREA ON MONDAY...BUT THE LATEST TRENDS
HAVE IT STALLING OVER MINNESOTA AND THEN LIFTING NORTH INTO ONTARIO
ON TUESDAY AS THE NEXT LOW DEVELOPS. THAT LOW WILL LIFT FROM
EASTERN MONTANA EARLY TUESDAY MORNING TO JAMES BAY BY WEDNESDAY
EVENING. THE WAY IT LOOKS NOW...THE U.P. WILL BE IN THE WARM SECTOR
FOR MOST OF THAT TIME FRAME AND EXPECT LITTLE TO NO PRECIPITATION
TO OCCUR. THUS...HAVE TRENDED POPS DOWN FOR TUESDAY...BUT DID BRING
IN SOME SLIGHT/CHANCE POPS TO THE WESTERN CWA FOR WEDNESDAY AS THE
COLD FRONT ASSOCIATED WITH THE SECOND LOW NEARS THE AREA. EXPECT
THAT COLD FRONT TO MOVE THROUGH ON WEDNESDAY NIGHT AND HAVE
INCREASED POPS TO HIGHER CHANCES. THE BREEZY SOUTHERLY WINDS FOR
MONDAY AND TUESDAY WILL WARM HIGHS TO ABOVE NORMAL VALUES AND
EXPECT HIGHS ON TUESDAY TO BE IN THE MID-UPPER 70S. EXPECT A SLIGHT
COOL DOWN BEHIND THE FRONT FOR THE END OF THE WORK WEEK...BUT
HIGHS WILL ONLY FALL TOWARDS MORE NORMAL VALUES FOR THIS TIME OF
YEAR (UPPER 60S TO AROUND 70).
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 216 PM EDT THU SEP 10 2015
VFR CONDITIONS WILL PREVAIL THRU AT LEAST THE EARLY EVENING HRS AT
KIWD/KCMX/KSAW. INCREASINGLY COLDER AIR...AN INCREASE IN LOW-LOW
LEVEL MOISTURE AND UPSLOPE FLOW SHOULD RESULT IN MVFR CIGS
DEVELOPING AT ALL TERMINALS OVERNIGHT. LIGHT LAKE EFFECT SHRA ARE
ALSO POSSIBLE...THOUGH IT APPEARS THE BETTER CHANCE WILL BE ON
FRIDAY.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 505 AM EDT THU SEP 10 2015
PASSING COLD FRONT THIS MORNING FOLLOWED BY INCREASINGLY COLDER AIR
FLOWING INTO THE UPPER GREAT LAKES WILL RESULT IN INCREASING WINDS
ON LAKE SUPERIOR TODAY AND TONIGHT. WINDS SHOULD BE MOSTLY UNDER
20KT THRU THE MORNING BEFORE GUSTS RAMP UP AND REACH 20-30KT
TONIGHT. STRONGEST WINDS SHOULD BE ACROSS CNTRL LAKE SUPERIOR. WHILE
WINDS WILL SLOWLY DIMINISH OVER THE WRN LAKE ON FRI...20-30KT WINDS
WILL CONTINUE OVER THE E. HIGH PRES RIDGE ARRIVES SAT...RESULTING IN
WINDS FALLING OFF TO UNDER 15KT. INCREASING S TO SW WINDS ARE
EXPECTED SUN INTO MON AS HIGH PRES RIDGE DEPARTS AND A LOW PRES TROF
APPROACHES FROM THE NW.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...SRF
AVIATION...JLA
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
219 PM EDT THU SEP 10 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 505 AM EDT THU SEP 10 2015
WATER VAPOR IMAGERY AND RAP ANALYSIS SHOW A TROF EXTENDING S INTO
THE NCNTRL STATES AND UPPER GREAT LAKES...ANCHORED BY A MID LEVEL
LOW OVER NRN ONTARIO. SHORTWAVE MOVING ACROSS NRN ONTARIO IS HELPING
TO DRIVE A COLD FRONT SE...CURRENTLY ACROSS WRN LAKE SUPERIOR. DEEP
LAYER FORCING PER QVECTORS IS SUPPORTING AN AREA OF SHRA MOVING
ACROSS NE WI INTO SCNTRL UPPER MI EARLY THIS MORNING. ISOLD SHRA
HAVE BEEN OCCURRING FARTHER N TO LAKE SUPERIOR. EVEN A TSTM WAS
NOTED OVER ERN LAKE SUPERIOR A FEW HRS AGO.
AS FORCING SUPPORTING THE NE WI PCPN SHIFTS E...THIS MORE ORGANIZED
SHRA AREA WILL MOVE ACROSS THE SCNTRL AND PORTIONS OF THE ERN FCST
AREA OVER THE NEXT FEW HRS. THIS MAIN AREA OF PCPN SHOULD BE E OF
THE AREA NO LATER THAN MID MORNING. WITH COLD FRONT STILL PUSHING
SE...POTENTIAL IS THERE FOR ADDITIONAL ISOLD TO SCT SHRA DEVELOPMENT
UNTIL FROPA. THIS POTENTIAL SHOULD INCREASE DURING THE AFTN AS SOME
INSTABILITY BUILDS UP AHEAD OF COLD FRONT. DEVELOPING LAKE BREEZE
OFF LAKE MICHIGAN WILL ALSO STRENGTHEN THE LOW-LEVEL CONVERGENCE
ALONG THE SE MOVING COLD FRONT. RAP AND GFS SHOW MLCAPES UPWARDS OF
200-300J/KG OVER THE SCNTRL/SE FCST AREA. 00Z NAM SHOWED MLCAPE OVER
1000J/KG. WHILE THE 06Z NAM HAS PULLED BACK TO 600-800J/KG...IT
STILL LOOKS OVERDONE. IN ANY EVENT...THE AVBL INSTABILITY SUGGESTS
THE POTENTIAL FOR ISOLD TSTMS OVER THE SCNTRL/SE FCST AREA THIS AFTN
ALONG/AHEAD OF COLD FRONT.
CAA TODAY/TONIGHT WILL DROP 850MB TEMPS DOWN TO 0 TO 2C OVER LAKE
SUPERIOR BY 12Z FRI...SUFFICIENT FOR LAKE EFFECT PROCESSES WITH
WATER TEMPS ROUGHLY 15-18C. WITH NAM/GFS FCST SOUNDINGS SHOWING A
WELL MIXED LAYER IN LOWER 2KFT OF THE AIR MASS...BELIEVE IT WILL
TAKE SOME TIME TO GET LAKE EFFECT GOING TONIGHT...ESPECIALLY IN
LIGHT OF THE LACK OF SYNOPTIC SUPPORT WITH DEEP LAYER QVECTOR
DIVERGENCE DOMINATING. NOT EXPECTING ANYTHING MORE THAN ISOLD TO
PERHAPS SCT -SHRA COVERAGE. WITH WATER TEMPS MORE IN THE 12-15C
RANGE OVER THE ERN LAKE...-SHRA COVERAGE WILL BE LEAST OVER THE ERN
FCST AREA. IN FACT...THERE MAY NOT BE ANY LAKE EFFECT -SHRA OVER THE
FAR E TONIGHT.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 316 AM EDT THU SEP 10 2015
UPPER PATTERN CONSISTS OF A 500 MB RIDGE OVER THE WESTERN U.S. WITH
A TROUGH OVER THE UPPER GREAT LAKES 12Z FRI WITH A DEEP TROUGH OVER
THE EAST HALF OF THE U.S. THE TROUGH AXIS IS OVER THE CWA 12Z FRI
AND SLOWLY MOVES TO THE EAST BY 00Z SAT. THE TROUGH CONTINUES TO DIG
SOUTHEAST WITH A DEEP TROUGH OVER THE ERN U.S. ON SAT.
WITH THE TROUGH AXIS MOVING ACROSS THE AREA ON FRI...STILL NEED TO
KEEP SOME POPS IN THE FORECAST ESPECIALLY FOR DIURNALLY DRIVEN
SHOWERS. ALSO IS COLD ENOUGH FOR LAKE EFFECT CONTRIBUTION AS WELL AS
LAKE SUPERIOR TEMPERATURES RANGE FROM 10C TO 15C AND 850 MB RANGE
FROM 0C TO 2C ON FRIDAY AND THAT IS ENOUGH LAKE-850 MB DELTA-T TO
DEFINITELY HAVE SOME LAKE CONTRIBUTION TO THE PCPN AS WELL. WITH
LOSS OF DIURNAL HEATING FRI NIGHT...DRY THINGS OUT AND KEEP THAT WAY
THROUGH SAT NIGHT. DID NOT MAKE TOO MANY CHANGES TO THE GOING
TEMPERATURES AS THEY LOOKED FINE. KEPT IN SOME PATCHY FROST FOR FRI
NIGHT AND SAT NIGHT IN THE INTERIOR WEST AS LOWS FALL TO THE MID 30S.
IN THE EXTENDED...GFS AND ECMWF SHOW A CLOSED 500 MB LOW OVER THE
LOWER GREAT LAKES 12Z SUN WITH A RIDGE OVER THE DESERT SW. SFC FRONT
ON IS PARALLEL WITH UPPER FLOW ON SUNDAY ACROSS SOUTH CENTRAL
CANADA. A BROAD 500 MB TROUGH OVER THE NORTHERN ROCKIES 12Z MON WILL
DIGS SOUTHEAST 12Z TUE WITH A SFC FRONT BECOMING STATIONARY OVER THE
AREA ON TUE. AS A RIDGE BUILDS INTO THE EASTERN U.S. ON WED...THIS
FRONT WILL HEAD BACK NORTH AS A WARM FRONT ON WED. WILL BE A WARMING
TREND STARTING ON MON WITH TEMPERATURES GOING ABOVE NORMAL. HAVE
SOME SLIGHT CHANCE POPS IN FOR TUE AND TUE NIGHT WITH THE FRONT NEAR
THE AREA AND CHANCE POPS ON WED AS THE FRONT MOVES NORTH AS A WARM
FRONT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 216 PM EDT THU SEP 10 2015
VFR CONDITIONS WILL PREVAIL THRU AT LEAST THE EARLY EVENING HRS AT
KIWD/KCMX/KSAW. INCREASINGLY COLDER AIR...AN INCREASE IN LOW-LOW
LEVEL MOISTURE AND UPSLOPE FLOW SHOULD RESULT IN MVFR CIGS
DEVELOPING AT ALL TERMINALS OVERNIGHT. LIGHT LAKE EFFECT SHRA ARE
ALSO POSSIBLE...THOUGH IT APPEARS THE BETTER CHANCE WILL BE ON
FRIDAY.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 505 AM EDT THU SEP 10 2015
PASSING COLD FRONT THIS MORNING FOLLOWED BY INCREASINGLY COLDER AIR
FLOWING INTO THE UPPER GREAT LAKES WILL RESULT IN INCREASING WINDS
ON LAKE SUPERIOR TODAY AND TONIGHT. WINDS SHOULD BE MOSTLY UNDER
20KT THRU THE MORNING BEFORE GUSTS RAMP UP AND REACH 20-30KT
TONIGHT. STRONGEST WINDS SHOULD BE ACROSS CNTRL LAKE SUPERIOR. WHILE
WINDS WILL SLOWLY DIMINISH OVER THE WRN LAKE ON FRI...20-30KT WINDS
WILL CONTINUE OVER THE E. HIGH PRES RIDGE ARRIVES SAT...RESULTING IN
WINDS FALLING OFF TO UNDER 15KT. INCREASING S TO SW WINDS ARE
EXPECTED SUN INTO MON AS HIGH PRES RIDGE DEPARTS AND A LOW PRES TROF
APPROACHES FROM THE NW.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...07
AVIATION...JLA
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
140 PM EDT THU SEP 10 2015
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 325 AM EDT THU SEP 10 2015
A TASTE OF EARLY FALL WILL COME SOUTHWEST MICHIGAN AS A POLAR COLD
FRONT MOVES ACROSS THE AREA LATER THIS AFTERNOON INTO EARLY
TONIGHT. THIS WILL BRING THE COOLEST AIR THIS AREA HAS SEEN SINCE
EARLY JUNG. SCATTERED SHOWERS WILL OVERSPREAD THE AREA FROM
NORTHWEST TO SOUTHEAST THIS AFTERNOON INTO THIS EVENING AS THE
COLD FRONT CROSSES THE AREA. FOR FRIDAY AND SATURDAY EXPECT
CONSIDERABLE CLOUD COVER...HIGHS ONLY FROM AROUND 60 TO THE MID
60S AND SCATTERED LAKE EFFECT SHOWERS. THE SHOWERS WILL BE
NUMEROUS NEAR THE LAKE MICHIGAN SHORE. SUNDAY INTO MONDAY THE COLD
AIR STARTS TO PULL AWAY FROM THE AREA SO SKIES WILL CLEAR AND
TEMPERATURES WILL SLOWLY WARM EACH DAY.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 325 AM EDT THU SEP 10 2015
OUR PRIMARY ISSUES ARE THE THREAT OF CONVECTION WITH THE COLD
FRONT THIS AFTERNOON INTO THIS EVENING...THEN WE WILL FOCUS ON THE
POTENTIAL FOR NORTH WIND LAKE EFFECT RAIN SHOWERS FOR THE FIRST
TIME THIS SEASON FOR FRIDAY INTO SATURDAY. BY SATURDAY MORNING THE
850 TEMPERATURE ANOMALIES AND THE 500 HEIGHTS WILL BE AROUND 4
STANDARD DEVIATIONS FROM NORMAL OVER THE LOWER GREAT LAKES INTO
THE OHIO VALLEY.
A 130 KNOT JET ROUNDING THE BASE OF THE TROUGH IN THE GULF OF
ALASKA EARLY THIS MORNING WILL INCREASE TO NEAR 145 KNOTS BY
TONIGHT AS IT HEADS TOWARD SOUTHERN ALASKA. THAT PUMPS UP THE
DOWNSTREAM RIDGE OVER WESTERN NORTH AMERICA...WHICH IN TURN DEEPS
THE DOWN STREAM TROUGH (OVER THE NORTHERN PLAINS). BY FRIDAY
AFTERNOON WE WILL HAVE A 110 KNOT JET CORE DIVING SOUTHWARD INTO
THE DEEPENING TROUGH OVER THE CENTRAL CANADA AND THE NORTHERN
PLAINS AND GREAT LAKES. THIS ACTION WILL LEAD TO A CLOSED UPPER
LOW BY SATURDAY MORNING OVER INDIANA AND WESTERN OHIO.
SO AS TYPICAL OF THIS SORT OF SET UP...THERE IS A BAND OF
CONVECTION HEAD OF THE COLD FRONT. MOISTURE TRANSPORT VECTORS IN
THE 1000/850 LAYER FOCUS THE BEST SHOWERS OVER NORTHERN LOWER
MICHIGAN THIS AFTERNOON AND EVENING. EVEN SO WITH PRECIPITABLE
WATER VALUES RISING TO AROUND 1.2 INCHES (ABOUT 150 PERCENT OF
NORMAL) THERE SHOULD BE ENOUGH MOISTURE FOR SOME SHOWERS THIS
AFTERNOON INTO THIS EVENING. THERE IS SOME MARGINAL INSTABILITY
BUT THE THE BEST CHANCE FOR THUNDERSTORMS WILL BE OVER NORTHWEST
SECTIONS LATE THIS AFTERNOON. AFTER THAT INSTABILITY IS TO FEEBLE
FOR THUNDERSTORMS.
ONCE IN THE COLD AIR WE SET UP FOR A NORTH WIND LAKE EFFECT EVENT
THAT COMMENCES ON FRIDAY AND LASTS INTO SATURDAY. ON FRIDAY
SOUNDING SUGGEST THERE IS ENOUGH INSTABLITLY FOR EQUILIBRIUM
LEVELS TO BE NEAR 20000 FT... MORE THAN ENOUGH FOR SHOWERS. ON
SATURDAY THE MOISTURE DEPTH IS LESS SO THE SHOWERS WILL MOSTLY BE
NEAR THE LAKE SHORE. ANOTHER ASPECT TO THIS THAT FAVORS SHOWERS IS
THAT LOWER MICHIGAN IS IN THE DEEP COLD AIR...INSIDE THE
CYCLONICLY CURVED JET AROUND THE OUTSIDE OF THE UPPER LOW. THE
BACK SIDE OF THAT JET DOES NOT CROSS SOUTHWEST MICHIGAN UNTIL
SUNDAY AFTERNOON. HAVING 850 MB TEMPERATURES FALL TO BETWEEN 2C
AND 4C..GIVEN THE 20C LAKE TEMPERATURES WILL BE MORE THAN COLD
ENOUGH FOR LAKE EFFECT SHOWERS TOO. ONCE AGAIN...WITH NORTH WINDS
THE SHOWERS WILL BE MOSTLY NEAR AND WEST OF US-31 FRIDAY AFTERNOON
INTO SATURDAY AFTERNOON.
INLAND SATURDAY MORNING SKIES MAY CLEAR SOMEWHAT SO WE COULD SEE
LOWS IN THE UPPER 30S IN THE NORMAL COOLER AREAS. I DO NOT THINK
FROST IS AN ISSUE YET. THAT WILL NOT BE TO FAR DOWN THE ROAD
THROUGH.
.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 325 AM EDT THU SEP 10 2015
A DRY PATTERN IS SETTING UP FOR MUCH OF THE LONG TERM. THE UPPER
TROUGH WILL BE MOVE EAST OUT OF THE CWA SATURDAY NIGHT AND AS SKIES
CLEAR TEMPS SHOULD FALL INTO THE LOWER TO MID 40S WITH SOME OF THE
COLDER SPOTS IN THE NORTHERN CWA REACHING THE UPPER 30S. AS THE SFC
RIDGE AXIS MOVES EAST BEGINNING SUNDAY WE/LL SEE TEMPS BEGIN TO
RISE. SUNDAY WILL STILL BE COOL WITH HIGHS IN THE MID 60S BUT HIGHS
WILL CLIMB INTO THE 70S BY MONDAY AND MAY APPROACH 80 BY MID WEEK.
RIDGING AT THE SFC AND ALOFT WILL MEAN DRY WX THROUGH TUESDAY NIGHT
AND MUCH OF WEDNESDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 133 PM EDT THU SEP 10 2015
PATCHY MVFR CLOUDS EXIST WEST AND NORTH OF KMKG. LOOKS LIKE KMKG
COULD SEE A BRIEF PERIOD OF MVFR DUE TO THE INCREASING LOW LEVEL
MOISTURE. VFR WEATHER SHOULD PREVAIL THROUGH THE AFTERNOON AND
INTO THE EVENING AT THE REMAINDER OF THE TAF SITES IN SW LOWER
MI. A WAVE OF LOW PRESSURE TRACKS TOWARD SOUTHERN LOWER MI LATER
TONIGHT AND FRIDAY. THIS FEATURE WILL LIKELY SPREAD A BAND OF RAIN
INTO PARTS OF LOWER MI. THE INCREASING LOW LEVEL MOISTURE SHOULD
ALLOW FOR MVFR AND EVEN SOME IFR FOR SOUTHERN LOWER MI. THE LOWEST
CONDITIONS ARE FORECASTED FOR KAZO...KBTL AND KJXN.
THE RAIN PULLS AWAY FRIDAY AM. CONDITIONS WILL SLOWLY IMPROVE FROM
WEST TO EAST DURING THE DAY. LAKE EFFECT RAIN SHOWERS COULD
LOCALLY CAUSE IMPACTS ALONG THE LAKESHORE FRIDAY AFTERNOON.
&&
.MARINE...
ISSUED AT 929 AM EDT THU SEP 10 2015
WINDS AND WAVES HAVE INCREASED IN THE NEARSHORE ZONES FROM
PENTWATER TO MUSKEGON AS THE BAND OF SHOWERS AND ISOLATED
THUNDERSTORMS COMES ONSHORE. RAP AND WAVE MODELS SHOW THIS
INCREASE IN THE NEAR TERM...WITH CONDITIONS DIMINISHING THIS
AFTERNOON. WILL KEEP THE MARINE PRODUCTS HEADLINE FREE FOR
NOW...AND INSTEAD INCREASE THE WAVE HEIGHTS AND WINDS SLIGHTLY.
&&
.HYDROLOGY...
ISSUED AT 1116 AM EDT WED SEP 9 2015
CONCERNS FOR FLOODING IN THE FORECAST AREA HAVE DRASTICALLY
DECREASED SINCE YESTERDAY AND REMAIN FAIRLY LOW THROUGH THE NEXT
SEVERAL DAYS.
24 TO 48 HOUR RAINFALL TOTALS THIS MORNING REFLECT THAT 2.00+ INCH
AMOUNTS WERE RELATIVELY HARD TO COME BY. AMOUNTS OF 1-2 INCHES
FELL IN A SWATH FROM MUSKEGON TO LUDINGTON AND EASTWARD TO MOUNT
PLEASANT AND HARRISON. A MAJORITY OF LOCATIONS TO THE SOUTH LANDED
IN THE TERRITORY OF ONE-QUARTER TO THREE-QUARTERS OF AN INCH WITH
EXCEPTION TO THOSE AFFECTED BY LOCALIZED HEAVY RAINFALL.
AREA RIVERS HAVE SHOWN UPWARD MOVEMENT...ESPECIALLY IN PLACES THAT
EXCEEDED 1.50 INCHES OF RAINFALL. FORTUNATELY...WE DODGED A
BULLET IN THE SENSE THAT NO REPORTS OF 3.00+ INCHES WERE RECEIVED IN
THE LAST 24 HOURS. THOSE WHO RECEIVED HEAVIER RAINFALL TWO DAYS
AGO...PARTICULARLY INGHAM COUNTY...WERE SPARED OF HEAVIER RAINFALL
YESTERDAY. OVERALL...THE NEXT 36 HOURS OF DRY WEATHER WILL BODE
WELL FOR STREAMS AND RIVERS TO STABILIZE AND BEGIN TRENDING
DOWNWARD. RAINFALL IS EXPECTED LATE THURSDAY INTO FRIDAY WITH
OVERALL AMOUNTS REMAINING AROUND OR LESS THAN ONE-HALF AN INCH.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...WDM
SHORT TERM...WDM
LONG TERM...99
AVIATION...MJS
HYDROLOGY...JAM
MARINE...MWS
AREA FORECAST DISCUSSION
NWS GAYLORD MI
133 PM EDT THU SEP 10 2015
.UPDATE...
ISSUED AT 1105 AM EDT THU SEP 10 2015
UPSTREAM COLD FRONT CURRENTLY EXTENDS FROM CENTRAL UPPER MICHIGAN
THRU WISCONSIN INTO FAR ERN IOWA. THICK LINE OF SHOWERS CONTINUES
TO SLOWLY MOVE EASTWARD THRU OUR CWA LATE THIS MORNING. SOME
HIGHER REFLECTIVITIES...WHICH MAY HAVE RESULTED IN A FEW HITS OF
LIGHTNING...WERE NOTED AN HOUR OR SO AGO OVER LAKE MICHIGAN...BUT
HAVE SINCE DIMINISHED IN INTENSITY. NAM12...RAP13 AND HRRR ALL
SHOW VERY WEAK INSTABILITY DEVELOPING THIS AFTERNOON/EVENING
ACROSS OUR CWA...WITH CAPES ONLY INCREASING TO 500 JOULES OR LESS.
SOME WEAK COOLING ALOFT COMBINED WITH LIMITED LOW LEVEL DIURNAL
HEATING WILL LEND TO MINOR DESTABILIZATION THIS AFTERNOON...WHICH
MAY LEAD TO A FEW ADDITIONAL HITS OF LIGHTNING. HAVE ADDED A
SLIGHT CHANCE OF THUNDER TO ENTIRE CWA THIS MORNING...AND
CONTINUED THIS THRU THE AFTERNOON AS WELL. HAVE ALSO INCREASED
POPS IN MOST LOCATIONS...AND MAY NEED TO FURTHER INCREASE POPS IN
OUR ERN CWA IF THIS AREA OF SHOWERS CONTINUES TO HOLD TOGETHER.
&&
.NEAR TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 353 AM EDT THU SEP 10 2015
...A FEW SHOWERS AND POSSIBLY A THUNDERSTORM OR TWO TODAY...
SLOWLY FALLING HEIGHTS THROUGH THE PERIOD AS UPPER LEVEL TROUGHING
CENTERED ACROSS CENTRAL CANADA DIGS INTO THE GREAT LAKES. SHORT
WAVES MOVING THROUGH THE FLOW IN COMBINATION WITH CONVERGENCE ALONG
A SURFACE COLD FRONT WILL LEAD TO INCREASING SHOWER CHANCES TODAY
(FIRST ACROSS NORTHWEST ZONES THIS MORNING THEN FOR MUCH OF THE
REGION THIS AFTERNOON). IN ADDITION...A BIT OF INSTABILITY
(SEVERAL HUNDRED J/KG OF 0-1 KM MIXED LAYER CAPE) WILL LEAD TO
SLIGHT CHANCES FOR THUNDER THIS AFTERNOON. AS THE COOLER AIR
DEEPENS TONIGHT THE CHANCES FOR LAKE EFFECT RAIN SHOWERS INCREASE
AS 850 MB TEMPS DROP TO BETWEEN PLUS 3 AND PLUS 5 C. HIGHS TODAY
NEAR AVERAGE FOR THE DATE...UPPER 60S AND LOWER 70S. COOLER
TONIGHT THAN ANY TIME RECENTLY WITH LOWS IN THE MIDDLE 40S TO
MIDDLE 50S.
&&
.SHORT TERM...(FRIDAY THROUGH SATURDAY NIGHT)
ISSUED AT 353 AM EDT THU SEP 10 2015
HIGH IMPACT WEATHER: WATERSPOUT POTENTIAL ON FRIDAY NIGHT AND
SATURDAY.
FORECAST CHALLENGE: LAKE EFFECT RAIN POTENTIAL, AND WATERSPOUT
POTENTIAL FOR FRIDAY AND SATURDAY.
(9/11)FRIDAY...THE MAIN FRONT IS SOUTH OF THE FORECAST AREA, AND THE
COLD AIR ADVECTION IS REALLY PRESSING IN BY 12Z. IN FACT, THE GFS
HAS BECOME MUCH MORE AGGRESSIVE WITH THE COLD AIR AS IT HAS +2C IN N
LAKE MICHIGAN, WHILE THE ECMWF IS AROUND 4C. WINDS IN THE 1000-850
MB LAYER ARE OUT OF THE NNW MOST OF THE DAY, WITH THE MOISTURE IN
THE 850-700 MB LAYER AROUND 70% MOST OF THE DAY AS WELL. (REMEMBER
THE WATER TEMPERATURES ARE STILL AROUND 20C IN N LAKE MICHIGAN.
STILL A LITTLE CONCERNED IN E LAKE SUPERIOR WITH 15-20C WATER, BUT
IT LOOKS LIKE THE 850 MB TEMPERATURES ONLY FLIRT WITH 0C, WHICH
WOULD CAUSE MORE INSTABILITY AND RAIN SHOWERS FOR BETTER LAKE EFFECT
RAIN THERE, BUT AS IT STANDS, THERE WILL BE MARGINAL INSTABILITY IN
E UPPER AS THE WINDS CONTINUE TO VEER NORTH THROUGH THE NIGHT. SO
THIS LOOKS TO AFFECT THE REGION FROM AROUND TVC TO AND WEST ALONG
THE LAKE MICHIGAN SHORELINE TO MBL. SOUNDINGS DURING THE DAY AND
INTO THE NIGHT, DON`T LOOK THAT GREAT AS THE SOUNDINGS LOOK A LITTLE
DRY, TO ME. SO HAVE KEPT THE POPS TO HIGH CHANCE OVER N FLOW
REGIONS. OF COURSE WITH THE TALK OF LAKE EFFECT RAIN, THE CHANCE FOR
WATER SPOUTS IS HIGHER, WITH THE 500 MB CUT OFF LOW ROTATING OVER
THE REGION AND EQUILIBRIUM LEVELS OF AROUND 10K FEET IF MODIFYING TO
THE LOWER PART OF THE SOUNDINGS TO THE WATER TEMPERATURES.
(9/12)SATURDAY...IT LOOKS LIKE THAT THE BEGINNING OF THE DAY SHOULD
CONTINUE THE CHANCE FOR LE RAIN SHOWERS IN THE WEST, WITH THE CHANCE
FOR WATERSPOUTS AS WELL, BUT THE LATER WE GET INTO THE DAY, THE
SOUNDINGS BEGIN TO DRY OUT SO THAT BY 00Z, THE SKIES SHOULD BEGIN TO
CLEAR OUT ALONG THE LAKE MICHIGAN SHORELINE. ESPECIALLY AS THE 850
MB TEMPERATURES WARM WITH THE SFC HIGH BUILDING INTO THE REGION, AND
THE 500 MB LOW MOVING OFF TO THE EAST.
&&
.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 353 AM EDT THU SEP 10 2015
WITH THE 500 MB LOW MOVING TO
THE EAST, THE PATTERN BECOMES QUITE AMPLIFIED AS 500 MB RIDGING
DOMINATES THE UPPER GREAT LAKES THROUGH TUESDAY NIGHT. THEN
WEDNESDAY, AND IT LOOKS LIKE LATE IN THE DAY, THE RIDGE BEGINS TO
BREAK DOWN WITH THE ANOTHER COLD FRONT WITH THE CHANCE FOR RAIN TO
MOVES INTO THE REGION OVERNIGHT WEDNESDAY AND INTO THURSDAY.
TEMPERATURES LOOK TO BE ABOVE NORMAL FOR A DAY OR TWO BEFORE COMING
BACK DOWN.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 133 PM EDT THU SEP 10 2015
A COLD FRONT WILL SWING THRU MICHIGAN THIS AFTERNOON AND
TONIGHT...PRODUCING SCATTERED SHOWERS. AN ISOLD THUNDERSTORM IS
ALSO POSSIBLE...BUT CHANCES ARE TOO LOW TO INCLUDE IN THE TAF
FORECAST. OVERALL CONDITIONS WILL REMAIN LOW VFR/HIGH MVFR THRU
FRIDAY AFTERNOON AS THIS FRONT SWINGS THRU. CAA IN THE WAKE OF THE
FRONT WILL DROP TEMPS LATER TONIGHT INTO FRIDAY AND WILL PRODUCE
SCATTERED LAKE ENHANCED RAIN SHOWERS...ESPECIALLY ACROSS NW LWR
MICHIGAN (PLN/TVC/MBL).
&&
.MARINE...
ISSUED AT 353 AM EDT THU SEP 10 2015
WINDS WILL BE SOUTHWEST TODAY THEN A COLD FRONT PASSES...SHIFTING
WINDS INTO THE NORTH TONIGHT. COLDER AIR AND AN UPPER LEVEL TROUGH
OVER THE GREAT LAKES REGION WILL RESULT IN WATERSPOUTS BECOMING A
GREATER THREAT...ESPECIALLY FRIDAY NIGHT.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
UPDATE...MLR
NEAR TERM...SULLIVAN
SHORT TERM...JSL
LONG TERM...JSL
AVIATION...MLR
MARINE...SULLIVAN
AREA FORECAST DISCUSSION
NWS GAYLORD MI
1105 AM EDT THU SEP 10 2015
.UPDATE...
ISSUED AT 1105 AM EDT THU SEP 10 2015
UPSTREAM COLD FRONT CURRENTLY EXTENDS FROM CENTRAL UPPER MICHIGAN
THRU WISCONSIN INTO FAR ERN IOWA. THICK LINE OF SHOWERS CONTINUES
TO SLOWLY MOVE EASTWARD THRU OUR CWA LATE THIS MORNING. SOME
HIGHER REFLECTIVITIES...WHICH MAY HAVE RESULTED IN A FEW HITS OF
LIGHTNING...WERE NOTED AN HOUR OR SO AGO OVER LAKE MICHIGAN...BUT
HAVE SINCE DIMINISHED IN INTENSITY. NAM12...RAP13 AND HRRR ALL
SHOW VERY WEAK INSTABILITY DEVELOPING THIS AFTERNOON/EVENING
ACROSS OUR CWA...WITH CAPES ONLY INCREASING TO 500 JOULES OR LESS.
SOME WEAK COOLING ALOFT COMBINED WITH LIMITED LOW LEVEL DIURNAL
HEATING WILL LEND TO MINOR DESTABILIZATION THIS AFTERNOON...WHICH
MAY LEAD TO A FEW ADDITIONAL HITS OF LIGHTNING. HAVE ADDED A
SLIGHT CHANCE OF THUNDER TO ENTIRE CWA THIS MORNING...AND
CONTINUED THIS THRU THE AFTERNOON AS WELL. HAVE ALSO INCREASED
POPS IN MOST LOCATIONS...AND MAY NEED TO FURTHER INCREASE POPS IN
OUR ERN CWA IF THIS AREA OF SHOWERS CONTINUES TO HOLD TOGETHER.
&&
.NEAR TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 353 AM EDT THU SEP 10 2015
...A FEW SHOWERS AND POSSIBLY A THUNDERSTORM OR TWO TODAY...
SLOWLY FALLING HEIGHTS THROUGH THE PERIOD AS UPPER LEVEL TROUGHING
CENTERED ACROSS CENTRAL CANADA DIGS INTO THE GREAT LAKES. SHORT
WAVES MOVING THROUGH THE FLOW IN COMBINATION WITH CONVERGENCE ALONG
A SURFACE COLD FRONT WILL LEAD TO INCREASING SHOWER CHANCES TODAY
(FIRST ACROSS NORTHWEST ZONES THIS MORNING THEN FOR MUCH OF THE
REGION THIS AFTERNOON). IN ADDITION...A BIT OF INSTABILITY
(SEVERAL HUNDRED J/KG OF 0-1 KM MIXED LAYER CAPE) WILL LEAD TO
SLIGHT CHANCES FOR THUNDER THIS AFTERNOON. AS THE COOLER AIR
DEEPENS TONIGHT THE CHANCES FOR LAKE EFFECT RAIN SHOWERS INCREASE
AS 850 MB TEMPS DROP TO BETWEEN PLUS 3 AND PLUS 5 C. HIGHS TODAY
NEAR AVERAGE FOR THE DATE...UPPER 60S AND LOWER 70S. COOLER
TONIGHT THAN ANY TIME RECENTLY WITH LOWS IN THE MIDDLE 40S TO
MIDDLE 50S.
&&
.SHORT TERM...(FRIDAY THROUGH SATURDAY NIGHT)
ISSUED AT 353 AM EDT THU SEP 10 2015
HIGH IMPACT WEATHER: WATERSPOUT POTENTIAL ON FRIDAY NIGHT AND
SATURDAY.
FORECAST CHALLENGE: LAKE EFFECT RAIN POTENTIAL, AND WATERSPOUT
POTENTIAL FOR FRIDAY AND SATURDAY.
(9/11)FRIDAY...THE MAIN FRONT IS SOUTH OF THE FORECAST AREA, AND THE
COLD AIR ADVECTION IS REALLY PRESSING IN BY 12Z. IN FACT, THE GFS
HAS BECOME MUCH MORE AGGRESSIVE WITH THE COLD AIR AS IT HAS +2C IN N
LAKE MICHIGAN, WHILE THE ECMWF IS AROUND 4C. WINDS IN THE 1000-850
MB LAYER ARE OUT OF THE NNW MOST OF THE DAY, WITH THE MOISTURE IN
THE 850-700 MB LAYER AROUND 70% MOST OF THE DAY AS WELL. (REMEMBER
THE WATER TEMPERATURES ARE STILL AROUND 20C IN N LAKE MICHIGAN.
STILL A LITTLE CONCERNED IN E LAKE SUPERIOR WITH 15-20C WATER, BUT
IT LOOKS LIKE THE 850 MB TEMPERATURES ONLY FLIRT WITH 0C, WHICH
WOULD CAUSE MORE INSTABILITY AND RAIN SHOWERS FOR BETTER LAKE EFFECT
RAIN THERE, BUT AS IT STANDS, THERE WILL BE MARGINAL INSTABILITY IN
E UPPER AS THE WINDS CONTINUE TO VEER NORTH THROUGH THE NIGHT. SO
THIS LOOKS TO AFFECT THE REGION FROM AROUND TVC TO AND WEST ALONG
THE LAKE MICHIGAN SHORELINE TO MBL. SOUNDINGS DURING THE DAY AND
INTO THE NIGHT, DON`T LOOK THAT GREAT AS THE SOUNDINGS LOOK A LITTLE
DRY, TO ME. SO HAVE KEPT THE POPS TO HIGH CHANCE OVER N FLOW
REGIONS. OF COURSE WITH THE TALK OF LAKE EFFECT RAIN, THE CHANCE FOR
WATER SPOUTS IS HIGHER, WITH THE 500 MB CUT OFF LOW ROTATING OVER
THE REGION AND EQUILIBRIUM LEVELS OF AROUND 10K FEET IF MODIFYING TO
THE LOWER PART OF THE SOUNDINGS TO THE WATER TEMPERATURES.
(9/12)SATURDAY...IT LOOKS LIKE THAT THE BEGINNING OF THE DAY SHOULD
CONTINUE THE CHANCE FOR LE RAIN SHOWERS IN THE WEST, WITH THE CHANCE
FOR WATERSPOUTS AS WELL, BUT THE LATER WE GET INTO THE DAY, THE
SOUNDINGS BEGIN TO DRY OUT SO THAT BY 00Z, THE SKIES SHOULD BEGIN TO
CLEAR OUT ALONG THE LAKE MICHIGAN SHORELINE. ESPECIALLY AS THE 850
MB TEMPERATURES WARM WITH THE SFC HIGH BUILDING INTO THE REGION, AND
THE 500 MB LOW MOVING OFF TO THE EAST.
&&
.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 353 AM EDT THU SEP 10 2015
WITH THE 500 MB LOW MOVING TO
THE EAST, THE PATTERN BECOMES QUITE AMPLIFIED AS 500 MB RIDGING
DOMINATES THE UPPER GREAT LAKES THROUGH TUESDAY NIGHT. THEN
WEDNESDAY, AND IT LOOKS LIKE LATE IN THE DAY, THE RIDGE BEGINS TO
BREAK DOWN WITH THE ANOTHER COLD FRONT WITH THE CHANCE FOR RAIN TO
MOVES INTO THE REGION OVERNIGHT WEDNESDAY AND INTO THURSDAY.
TEMPERATURES LOOK TO BE ABOVE NORMAL FOR A DAY OR TWO BEFORE COMING
BACK DOWN.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 702 AM EDT THU SEP 10 2015
MID LEVEL CLOUD HAVE OVERSPREAD THE REGION AND WILL CONTINUE
ACROSS THE AREA TODAY. MEANWHILE...LIGHT RAIN SHOWERS WILL
OVERSPREAD THE TAF SITES THIS MORNING AND CONTINUE INTO THIS
AFTERNOON. A RUMBLE OF THUNDER CANNOT BE RULED OUT...BUT TOO
ISOLATED TO INCLUDE IN THE TAFS. A COLD FRONT MOVES THROUGH THIS
AFTERNOON...WITH WINDS SHIFTING INTO THE WEST NORTHWEST. SPEEDS
ALL UNDER 10 KTS. LAKE EFFECT RAIN SHOWERS WILL LIKELY DEVELOP
LATER TONIGHT. CIGS/VSBYS LIKELY VFR FOR MUCH OF TODAY...TRENDING
MVFR TONIGHT.
&&
.MARINE...
ISSUED AT 353 AM EDT THU SEP 10 2015
WINDS WILL BE SOUTHWEST TODAY THEN A COLD FRONT PASSES...SHIFTING
WINDS INTO THE NORTH TONIGHT. COLDER AIR AND AN UPPER LEVEL TROUGH
OVER THE GREAT LAKES REGION WILL RESULT IN WATERSPOUTS BECOMING A
GREATER THREAT...ESPECIALLY FRIDAY NIGHT.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
UPDATE...MLR
NEAR TERM...SULLIVAN
SHORT TERM...JSL
LONG TERM...JSL
AVIATION...SULLIVAN
MARINE...SULLIVAN
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
935 AM EDT THU SEP 10 2015
LATEST UPDATE...
MARINE
.SYNOPSIS...
ISSUED AT 325 AM EDT THU SEP 10 2015
A TASTE OF EARLY FALL WILL COME SOUTHWEST MICHIGAN AS A POLAR COLD
FRONT MOVES ACROSS THE AREA LATER THIS AFTERNOON INTO EARLY
TONIGHT. THIS WILL BRING THE COOLEST AIR THIS AREA HAS SEEN SINCE
EARLY JUNE. SCATTERED SHOWERS WILL OVERSPEAD THE AREA FROM
NORTHWEST TO SOUTHEAST THIS AFTERNOON INTO THIS EVENING AS THE
COLD FRONT CROSSES THE AREA. FOR FRIDAY AND SATURDAY EXPECT
CONSIDERABLE CLOUD COVER...HIGHS ONLY FROM AROUND 60 TO THE MID
60S AND SCATTERED LAKE EFFECT SHOWERS. THE SHOWERS WILL BE
NUMEROUS NEAR THE LAKE MICHIGAN SHORE. SUNDAY INTO MONDAY THE COLD
AIR STARTS TO PULL AWAY FROM THE AREA SO SKIES WILL CLEAR AND
TEMPERATURES WILL SLOWLY WARM EACH DAY.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 325 AM EDT THU SEP 10 2015
OUR PRIMARY ISSUES ARE THE THREAT OF CONVECTION WITH THE COLD
FRONT THIS AFTERNOON INTO THIS EVENING...THEN WE WILL FOCUS ON THE
POTENTIAL FOR NORTH WIND LAKE EFFECT RAIN SHOWERS FOR THE FIRST
TIME THIS SEASON FOR FRIDAY INTO SATURDAY. BY SATURDAY MORNING THE
850 TEMPERATURE ANOMALIES AND THE 500 HEIGHTS WILL BE AROUND 4
STANDARD DEVIATIONS FROM NORMAL OVER THE LOWER GREAT LAKES INTO
THE OHIO VALLEY.
A 130 KNOT JET ROUNDING THE BASE OF THE TROUGH IN THE GULF OF
ALASKA EARLY THIS MORNING WILL INCREASE TO NEAR 145 KNOTS BY
TONIGHT AS IT HEADS TOWARD SOUTHERN ALASKA. THAT PUMPS UP THE
DOWNSTREAM RIDGE OVER WESTERN NORTH AMERICA...WHICH IN TURN DEEPS
THE DOWN STREAM TROUGH (OVER THE NORTHERN PLAINS). BY FRIDAY
AFTERNOON WE WILL HAVE A 110 KNOT JET CORE DIVING SOUTHWARD INTO
THE DEEPENING TROUGH OVER THE CENTRAL CANADA AND THE NORTHERN
PLAINS AND GREAT LAKES. THIS ACTION WILL LEAD TO A CLOSED UPPER
LOW BY SATURDAY MORNING OVER INDIANA AND WESTERN OHIO.
SO AS TYPICAL OF THIS SORT OF SET UP...THERE IS A BAND OF
CONVECTION HEAD OF THE COLD FRONT. MOISTURE TRANSPORT VECTORS IN
THE 1000/850 LAYER FOCUS THE BEST SHOWERS OVER NORTHERN LOWER
MICHIGAN THIS AFTERNOON AND EVENING. EVEN SO WITH PRECIPITABLE
WATER VALUES RISING TO AROUND 1.2 INCHES (ABOUT 150 PERCENT OF
NORMAL) THERE SHOULD BE ENOUGH MOISTURE FOR SOME SHOWERS THIS
AFTERNOON INTO THIS EVENING. THERE IS SOME MARINGAL INSTABILITY BUT
THE THE BEST CHANCE FOR THUNDERSTORMS WILL BE OVER NORTHWEST
SECTIONS LATE THIS AFTERNOON. AFTER THAT INSTABILITY IS TO FEEBLE
FOR THUNDERSTORMS.
ONCE IN THE COLD AIR WE SET UP FOR A NORTH WIND LAKE EFFECT EVENT
THAT COMMENCES ON FRIDAY AND LASTS INTO SATURDAY. ON FRIDAY
SOUNDING SUGGEST THERE IS ENOUGH INSTABLITLY FOR EQUILIBRIUM
LEVELS TO BE NEAR 20000 FT... MORE THAN ENOUGH FOR SHOWERS. ON
SATURDAY THE MOISTURE DEPTH IS LESS SO THE SHOWERS WILL MOSTLY BE
NEAR THE LAKE SHORE. ANOTHER ASPECT TO THIS THAT FAVORS SHOWERS IS
THAT LOWER MICHIGAN IS IN THE DEEP COLD AIR...INSIDE THE
CYCLONICLY CURVED JET AROUND THE OUTSIDE OF THE UPPER LOW. THE
BACK SIDE OF THAT JET DOES NOT CROSS SOUTHWEST MICHIGAN UNTIL
SUNDAY AFTERNOON. HAVING 850 MB TEMPERATURES FALL TO BETWEEN 2C
AND 4C..GIVEN THE 20C LAKE TEMPERATURES WILL BE MORE THAN COLD
ENOUGH FOR LAKE EFFECT SHOWERS TOO. ONCE AGAIN...WITH NORTH WINDS
THE SHOWERS WILL BE MOSTLY NEAR AND WEST OF US-31 FRIDAY AFTERNOON
INTO SATURDAY AFTERNOON.
INLAND SATURDAY MORNING SKIES MAY CLEAR SOMEWHAT SO WE COULD SEE
LOWS IN THE UPPER 30S IN THE NORMAL COOLER AREAS. I DO NOT THINK
FROST IS AN ISSUE YET. THAT WILL NOT BE TO FAR DOWN THE ROAD
THROUGH.
.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 325 AM EDT THU SEP 10 2015
A DRY PATTERN IS SETTING UP FOR MUCH OF THE LONG TERM. THE UPPER
TROUGH WILL BE MOVE EAST OUT OF THE CWA SATURDAY NIGHT AND AS SKIES
CLEAR TEMPS SHOULD FALL INTO THE LOWER TO MID 40S WITH SOME OF THE
COLDER SPOTS IN THE NORTHERN CWA REACHING THE UPPER 30S. AS THE SFC
RIDGE AXIS MOVES EAST BEGINNING SUNDAY WE/LL SEE TEMPS BEGIN TO
RISE. SUNDAY WILL STILL BE COOL WITH HIGHS IN THE MID 60S BUT HIGHS
WILL CLIMB INTO THE 70S BY MONDAY AND MAY APPROACH 80 BY MID WEEK.
RIDGING AT THE SFC AND ALOFT WILL MEAN DRY WX THROUGH TUESDAY NIGHT
AND MUCH OF WEDNESDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 719 AM EDT THU SEP 10 2015
VFR CONDITIONS WILL PREVAIL INTO TONIGHT. OVERNIGHT AS THE COLDER
AIR STARTS COMING IN CELLING WILL LOWER TO MVFR. SHOWERS SHOULD
BECOME MORE WIDESPREAD AT THAT POINT TOO.
THERE IS AN AREA OF SHOWERS AND A FEW THUNDERSTORMS JUST AHEAD OF
THE COLD FRONT OVER LAKE MICHIGAN AND BACK INTO SOUTHERN
WISCONSIN. THE SHOWERS OVER LAKE MICHIGAN ARE DISSIPATING DUE TO
THE LACK OF MID AND LOW LEVEL MOISTURE. HOWEVER... THE SHOWERS
CURRENTLY OVER SOUTHERN WISCONSIN ARE BETTER SUPPORTED AND THEY
MAY BRING SOME LIGHT RAIN SHOWERS TO AT LEAST THE WESTERN TAF
SITES THIS AFTERNOON. CEILING WILL REMAIN VFR AS WELL AS THE
VISIBILITY.
&&
.MARINE...
ISSUED AT 929 AM EDT THU SEP 10 2015
WINDS AND WAVES HAVE INCREASED IN THE NEARSHORE ZONES FROM
PENTWATER TO MUSKEGON AS THE BAND OF SHOWERS AND ISOLATED
THUNDERSTORMS COMES ONSHORE. RAP AND WAVE MODELS SHOW THIS
INCREASE IN THE NEAR TERM...WITH CONDITIONS DIMINISHING THIS
AFTERNOON. WILL KEEP THE MARINE PRODUCTS HEADLINE FREE FOR
NOW...AND INSTEAD INCREASE THE WAVE HEIGHTS AND WINDS SLIGHTLY.
&&
.HYDROLOGY...
ISSUED AT 1116 AM EDT WED SEP 9 2015
CONCERNS FOR FLOODING IN THE FORECAST AREA HAVE DRASTICALLY
DECREASED SINCE YESTERDAY AND REMAIN FAIRLY LOW THROUGH THE NEXT
SEVERAL DAYS.
24 TO 48 HOUR RAINFALL TOTALS THIS MORNING REFLECT THAT 2.00+ INCH
AMOUNTS WERE RELATIVELY HARD TO COME BY. AMOUNTS OF 1-2 INCHES
FELL IN A SWATH FROM MUSKEGON TO LUDINGTON AND EASTWARD TO MOUNT
PLEASANT AND HARRISON. A MAJORITY OF LOCATIONS TO THE SOUTH LANDED
IN THE TERRITORY OF ONE-QUARTER TO THREE-QUARTERS OF AN INCH WITH
EXCEPTION TO THOSE AFFECTED BY LOCALIZED HEAVY RAINFALL.
AREA RIVERS HAVE SHOWN UPWARD MOVEMENT...ESPECIALLY IN PLACES THAT
EXCEEDED 1.50 INCHES OF RAINFALL. FORTUNATELY...WE DODGED A
BULLET IN THE SENSE THAT NO REPORTS OF 3.00+ INCHES WERE RECEIVED IN
THE LAST 24 HOURS. THOSE WHO RECEIVED HEAVIER RAINFALL TWO DAYS
AGO...PARTICULARLY INGHAM COUNTY...WERE SPARED OF HEAVIER RAINFALL
YESTERDAY. OVERALL...THE NEXT 36 HOURS OF DRY WEATHER WILL BODE
WELL FOR STREAMS AND RIVERS TO STABILIZE AND BEGIN TRENDING
DOWNWARD. RAINFALL IS EXPECTED LATE THURSDAY INTO FRIDAY WITH
OVERALL AMOUNTS REMAINING AROUND OR LESS THAN ONE-HALF AN INCH.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...WDM
SHORT TERM...WDM
LONG TERM...99
AVIATION...WDM
HYDROLOGY...JAM
MARINE...MWS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
747 AM EDT THU SEP 10 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 505 AM EDT THU SEP 10 2015
WATER VAPOR IMAGERY AND RAP ANALYSIS SHOW A TROF EXTENDING S INTO
THE NCNTRL STATES AND UPPER GREAT LAKES...ANCHORED BY A MID LEVEL
LOW OVER NRN ONTARIO. SHORTWAVE MOVING ACROSS NRN ONTARIO IS HELPING
TO DRIVE A COLD FRONT SE...CURRENTLY ACROSS WRN LAKE SUPERIOR. DEEP
LAYER FORCING PER QVECTORS IS SUPPORTING AN AREA OF SHRA MOVING
ACROSS NE WI INTO SCNTRL UPPER MI EARLY THIS MORNING. ISOLD SHRA
HAVE BEEN OCCURRING FARTHER N TO LAKE SUPERIOR. EVEN A TSTM WAS
NOTED OVER ERN LAKE SUPERIOR A FEW HRS AGO.
AS FORCING SUPPORTING THE NE WI PCPN SHIFTS E...THIS MORE ORGANIZED
SHRA AREA WILL MOVE ACROSS THE SCNTRL AND PORTIONS OF THE ERN FCST
AREA OVER THE NEXT FEW HRS. THIS MAIN AREA OF PCPN SHOULD BE E OF
THE AREA NO LATER THAN MID MORNING. WITH COLD FRONT STILL PUSHING
SE...POTENTIAL IS THERE FOR ADDITIONAL ISOLD TO SCT SHRA DEVELOPMENT
UNTIL FROPA. THIS POTENTIAL SHOULD INCREASE DURING THE AFTN AS SOME
INSTABILITY BUILDS UP AHEAD OF COLD FRONT. DEVELOPING LAKE BREEZE
OFF LAKE MICHIGAN WILL ALSO STRENGTHEN THE LOW-LEVEL CONVERGENCE
ALONG THE SE MOVING COLD FRONT. RAP AND GFS SHOW MLCAPES UPWARDS OF
200-300J/KG OVER THE SCNTRL/SE FCST AREA. 00Z NAM SHOWED MLCAPE OVER
1000J/KG. WHILE THE 06Z NAM HAS PULLED BACK TO 600-800J/KG...IT
STILL LOOKS OVERDONE. IN ANY EVENT...THE AVBL INSTABILITY SUGGESTS
THE POTENTIAL FOR ISOLD TSTMS OVER THE SCNTRL/SE FCST AREA THIS AFTN
ALONG/AHEAD OF COLD FRONT.
CAA TODAY/TONIGHT WILL DROP 850MB TEMPS DOWN TO 0 TO 2C OVER LAKE
SUPERIOR BY 12Z FRI...SUFFICIENT FOR LAKE EFFECT PROCESSES WITH
WATER TEMPS ROUGHLY 15-18C. WITH NAM/GFS FCST SOUNDINGS SHOWING A
WELL MIXED LAYER IN LOWER 2KFT OF THE AIR MASS...BELIEVE IT WILL
TAKE SOME TIME TO GET LAKE EFFECT GOING TONIGHT...ESPECIALLY IN
LIGHT OF THE LACK OF SYNOPTIC SUPPORT WITH DEEP LAYER QVECTOR
DIVERGENCE DOMINATING. NOT EXPECTING ANYTHING MORE THAN ISOLD TO
PERHAPS SCT -SHRA COVERAGE. WITH WATER TEMPS MORE IN THE 12-15C
RANGE OVER THE ERN LAKE...-SHRA COVERAGE WILL BE LEAST OVER THE ERN
FCST AREA. IN FACT...THERE MAY NOT BE ANY LAKE EFFECT -SHRA OVER THE
FAR E TONIGHT.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 316 AM EDT THU SEP 10 2015
UPPER PATTERN CONSISTS OF A 500 MB RIDGE OVER THE WESTERN U.S. WITH
A TROUGH OVER THE UPPER GREAT LAKES 12Z FRI WITH A DEEP TROUGH OVER
THE EAST HALF OF THE U.S. THE TROUGH AXIS IS OVER THE CWA 12Z FRI
AND SLOWLY MOVES TO THE EAST BY 00Z SAT. THE TROUGH CONTINUES TO DIG
SOUTHEAST WITH A DEEP TROUGH OVER THE ERN U.S. ON SAT.
WITH THE TROUGH AXIS MOVING ACROSS THE AREA ON FRI...STILL NEED TO
KEEP SOME POPS IN THE FORECAST ESPECIALLY FOR DIURNALLY DRIVEN
SHOWERS. ALSO IS COLD ENOUGH FOR LAKE EFFECT CONTRIBUTION AS WELL AS
LAKE SUPERIOR TEMPERATURES RANGE FROM 10C TO 15C AND 850 MB RANGE
FROM 0C TO 2C ON FRIDAY AND THAT IS ENOUGH LAKE-850 MB DELTA-T TO
DEFINITELY HAVE SOME LAKE CONTRIBUTION TO THE PCPN AS WELL. WITH
LOSS OF DIURNAL HEATING FRI NIGHT...DRY THINGS OUT AND KEEP THAT WAY
THROUGH SAT NIGHT. DID NOT MAKE TOO MANY CHANGES TO THE GOING
TEMPERATURES AS THEY LOOKED FINE. KEPT IN SOME PATCHY FROST FOR FRI
NIGHT AND SAT NIGHT IN THE INTERIOR WEST AS LOWS FALL TO THE MID 30S.
IN THE EXTENDED...GFS AND ECMWF SHOW A CLOSED 500 MB LOW OVER THE
LOWER GREAT LAKES 12Z SUN WITH A RIDGE OVER THE DESERT SW. SFC FRONT
ON IS PARALLEL WITH UPPER FLOW ON SUNDAY ACROSS SOUTH CENTRAL
CANADA. A BROAD 500 MB TROUGH OVER THE NORTHERN ROCKIES 12Z MON WILL
DIGS SOUTHEAST 12Z TUE WITH A SFC FRONT BECOMING STATIONARY OVER THE
AREA ON TUE. AS A RIDGE BUILDS INTO THE EASTERN U.S. ON WED...THIS
FRONT WILL HEAD BACK NORTH AS A WARM FRONT ON WED. WILL BE A WARMING
TREND STARTING ON MON WITH TEMPERATURES GOING ABOVE NORMAL. HAVE
SOME SLIGHT CHANCE POPS IN FOR TUE AND TUE NIGHT WITH THE FRONT NEAR
THE AREA AND CHANCE POPS ON WED AS THE FRONT MOVES NORTH AS A WARM
FRONT.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 746 AM EDT THU SEP 10 2015
VFR CONDITIONS WILL PREVAIL THRU AT LEAST THE EARLY EVENING HRS AT
KIWD/KCMX/KSAW. THERE MAY BE -SHRA THIS AFTN AT KSAW...BUT POTENTIAL
IS TOO LOW AT THIS POINT TO INCLUDE A MENTION IN FCST. INCREASINGLY
COLDER AIR...AN INCREASE IN LOW-LOW LEVEL MOISTURE AND UPSLOPE FLOW
SHOULD RESULT IN MVFR CIGS DEVELOPING AT ALL TERMINALS OVERNIGHT.
LIGHT LAKE EFFECT SHRA ARE ALSO POSSIBLE.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 505 AM EDT THU SEP 10 2015
PASSING COLD FRONT THIS MORNING FOLLOWED BY INCREASINGLY COLDER AIR
FLOWING INTO THE UPPER GREAT LAKES WILL RESULT IN INCREASING WINDS
ON LAKE SUPERIOR TODAY AND TONIGHT. WINDS SHOULD BE MOSTLY UNDER
20KT THRU THE MORNING BEFORE GUSTS RAMP UP AND REACH 20-30KT
TONIGHT. STRONGEST WINDS SHOULD BE ACROSS CNTRL LAKE SUPERIOR. WHILE
WINDS WILL SLOWLY DIMINISH OVER THE WRN LAKE ON FRI...20-30KT WINDS
WILL CONTINUE OVER THE E. HIGH PRES RIDGE ARRIVES SAT...RESULTING IN
WINDS FALLING OFF TO UNDER 15KT. INCREASING S TO SW WINDS ARE
EXPECTED SUN INTO MON AS HIGH PRES RIDGE DEPARTS AND A LOW PRES TROF
APPROACHES FROM THE NW.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...07
AVIATION...ROLFSON
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
506 AM EDT THU SEP 10 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 505 AM EDT THU SEP 10 2015
WATER VAPOR IMAGERY AND RAP ANALYSIS SHOW A TROF EXTENDING S INTO
THE NCNTRL STATES AND UPPER GREAT LAKES...ANCHORED BY A MID LEVEL
LOW OVER NRN ONTARIO. SHORTWAVE MOVING ACROSS NRN ONTARIO IS HELPING
TO DRIVE A COLD FRONT SE...CURRENTLY ACROSS WRN LAKE SUPERIOR. DEEP
LAYER FORCING PER QVECTORS IS SUPPORTING AN AREA OF SHRA MOVING
ACROSS NE WI INTO SCNTRL UPPER MI EARLY THIS MORNING. ISOLD SHRA
HAVE BEEN OCCURRING FARTHER N TO LAKE SUPERIOR. EVEN A TSTM WAS
NOTED OVER ERN LAKE SUPERIOR A FEW HRS AGO.
AS FORCING SUPPORTING THE NE WI PCPN SHIFTS E...THIS MORE ORGANIZED
SHRA AREA WILL MOVE ACROSS THE SCNTRL AND PORTIONS OF THE ERN FCST
AREA OVER THE NEXT FEW HRS. THIS MAIN AREA OF PCPN SHOULD BE E OF
THE AREA NO LATER THAN MID MORNING. WITH COLD FRONT STILL PUSHING
SE...POTENTIAL IS THERE FOR ADDITIONAL ISOLD TO SCT SHRA DEVELOPMENT
UNTIL FROPA. THIS POTENTIAL SHOULD INCREASE DURING THE AFTN AS SOME
INSTABILITY BUILDS UP AHEAD OF COLD FRONT. DEVELOPING LAKE BREEZE
OFF LAKE MICHIGAN WILL ALSO STRENGTHEN THE LOW-LEVEL CONVERGENCE
ALONG THE SE MOVING COLD FRONT. RAP AND GFS SHOW MLCAPES UPWARDS OF
200-300J/KG OVER THE SCNTRL/SE FCST AREA. 00Z NAM SHOWED MLCAPE OVER
1000J/KG. WHILE THE 06Z NAM HAS PULLED BACK TO 600-800J/KG...IT
STILL LOOKS OVERDONE. IN ANY EVENT...THE AVBL INSTABILITY SUGGESTS
THE POTENTIAL FOR ISOLD TSTMS OVER THE SCNTRL/SE FCST AREA THIS AFTN
ALONG/AHEAD OF COLD FRONT.
CAA TODAY/TONIGHT WILL DROP 850MB TEMPS DOWN TO 0 TO 2C OVER LAKE
SUPERIOR BY 12Z FRI...SUFFICIENT FOR LAKE EFFECT PROCESSES WITH
WATER TEMPS ROUGHLY 15-18C. WITH NAM/GFS FCST SOUNDINGS SHOWING A
WELL MIXED LAYER IN LOWER 2KFT OF THE AIR MASS...BELIEVE IT WILL
TAKE SOME TIME TO GET LAKE EFFECT GOING TONIGHT...ESPECIALLY IN
LIGHT OF THE LACK OF SYNOPTIC SUPPORT WITH DEEP LAYER QVECTOR
DIVERGENCE DOMINATING. NOT EXPECTING ANYTHING MORE THAN ISOLD TO
PERHAPS SCT -SHRA COVERAGE. WITH WATER TEMPS MORE IN THE 12-15C
RANGE OVER THE ERN LAKE...-SHRA COVERAGE WILL BE LEAST OVER THE ERN
FCST AREA. IN FACT...THERE MAY NOT BE ANY LAKE EFFECT -SHRA OVER THE
FAR E TONIGHT.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 316 AM EDT THU SEP 10 2015
UPPER PATTERN CONSISTS OF A 500 MB RIDGE OVER THE WESTERN U.S. WITH
A TROUGH OVER THE UPPER GREAT LAKES 12Z FRI WITH A DEEP TROUGH OVER
THE EAST HALF OF THE U.S. THE TROUGH AXIS IS OVER THE CWA 12Z FRI
AND SLOWLY MOVES TO THE EAST BY 00Z SAT. THE TROUGH CONTINUES TO DIG
SOUTHEAST WITH A DEEP TROUGH OVER THE ERN U.S. ON SAT.
WITH THE TROUGH AXIS MOVING ACROSS THE AREA ON FRI...STILL NEED TO
KEEP SOME POPS IN THE FORECAST ESPECIALLY FOR DIURNALLY DRIVEN
SHOWERS. ALSO IS COLD ENOUGH FOR LAKE EFFECT CONTRIBUTION AS WELL AS
LAKE SUPERIOR TEMPERATURES RANGE FROM 10C TO 15C AND 850 MB RANGE
FROM 0C TO 2C ON FRIDAY AND THAT IS ENOUGH LAKE-850 MB DELTA-T TO
DEFINITELY HAVE SOME LAKE CONTRIBUTION TO THE PCPN AS WELL. WITH
LOSS OF DIURNAL HEATING FRI NIGHT...DRY THINGS OUT AND KEEP THAT WAY
THROUGH SAT NIGHT. DID NOT MAKE TOO MANY CHANGES TO THE GOING
TEMPERATURES AS THEY LOOKED FINE. KEPT IN SOME PATCHY FROST FOR FRI
NIGHT AND SAT NIGHT IN THE INTERIOR WEST AS LOWS FALL TO THE MID 30S.
IN THE EXTENDED...GFS AND ECMWF SHOW A CLOSED 500 MB LOW OVER THE
LOWER GREAT LAKES 12Z SUN WITH A RIDGE OVER THE DESERT SW. SFC FRONT
ON IS PARALLEL WITH UPPER FLOW ON SUNDAY ACROSS SOUTH CENTRAL
CANADA. A BROAD 500 MB TROUGH OVER THE NORTHERN ROCKIES 12Z MON WILL
DIGS SOUTHEAST 12Z TUE WITH A SFC FRONT BECOMING STATIONARY OVER THE
AREA ON TUE. AS A RIDGE BUILDS INTO THE EASTERN U.S. ON WED...THIS
FRONT WILL HEAD BACK NORTH AS A WARM FRONT ON WED. WILL BE A WARMING
TREND STARTING ON MON WITH TEMPERATURES GOING ABOVE NORMAL. HAVE
SOME SLIGHT CHANCE POPS IN FOR TUE AND TUE NIGHT WITH THE FRONT NEAR
THE AREA AND CHANCE POPS ON WED AS THE FRONT MOVES NORTH AS A WARM
FRONT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 136 AM EDT THU SEP 10 2015
EXPECT VFR CONDITIONS THROUGH MOST OF THE FCST PERIOD. VFR CIGS WITH
MID CLOUDS WILL PREVAIL OVERNIGHT AS A DISTURBANCE MOVES THROUGH THE
REGION. THERE MAY BE A FEW SHOWERS OR SPRINKLES BUT MOST OF THE PCPN
IS EXPECTED TO REMAIN SOUTH OF THE TAF SITES AS FAIRLY DRY AIR
LINGERS IN THE LOWER LEVELS...KEEPING CIGS AOA 5K FT. AS A COLD FRONT
MOVES THROUGH TODAY AND WINDS VEER NRLY BY EVENING...THE COMBINATION
OF CAA AND INCREASING LOW LEVEL MOISTURE WITH UPSLOPE FLOW SHOULD
DROP CIGS INTO THE MVFR RANGE.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 505 AM EDT THU SEP 10 2015
PASSING COLD FRONT THIS MORNING FOLLOWED BY INCREASINGLY COLDER AIR
FLOWING INTO THE UPPER GREAT LAKES WILL RESULT IN INCREASING WINDS
ON LAKE SUPERIOR TODAY AND TONIGHT. WINDS SHOULD BE MOSTLY UNDER
20KT THRU THE MORNING BEFORE GUSTS RAMP UP AND REACH 20-30KT
TONIGHT. STRONGEST WINDS SHOULD BE ACROSS CNTRL LAKE SUPERIOR. WHILE
WINDS WILL SLOWLY DIMINISH OVER THE WRN LAKE ON FRI...20-30KT WINDS
WILL CONTINUE OVER THE E. HIGH PRES RIDGE ARRIVES SAT...RESULTING IN
WINDS FALLING OFF TO UNDER 15KT. INCREASING S TO SW WINDS ARE
EXPECTED SUN INTO MON AS HIGH PRES RIDGE DEPARTS AND A LOW PRES TROF
APPROACHES FROM THE NW.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...07
AVIATION...JLB
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
341 PM CDT THU SEP 10 2015
.SHORT TERM: (Through Late Tonight)
Issued at 338 PM CDT Thu Sep 10 2015
Spotty convection will continue across most of the FA early
this evening due to numerous outflow/surface boundaries migrating
through mostly unstable airmass of MLCAPES 1000-2000 j/kg. However,
still believe the primary "show" will be late this evening and
overnight as primary shortwave energy digs into the region and
begins to interact with southward sagging cold front/baroclinic
zone. Last several runs of the HRRR continue to support idea that
convection over NE will drop/develop across e KS and w MO during the
early evening hours as UVV increases due to shortwave as well as
increasing isentropic ascent, with the resultant elevated shower
and embedded thunderstorm threat overspreading much of the CWA
during the overnight hours. Have highest PoPs (~80%) over mid MO
where lift and moisture advection should be maximized...this is a
bit higher/bit further north than earlier forecast, but models are
still indicating good divergence developing across northern MO in
the RRQ of the back building upper level jet. PoPs then taper off
to high chance over far northern and southern sections of the FA as
precip should tend to "fade" a bit as it advects out of the primary
zone of ascent.
Truett
.LONG TERM: (Friday through Next Thursday)
Issued at 338 PM CDT Thu Sep 10 2015
Even though frontal boundary will be south of forecast area by 12z
Friday, will see some lingering post frontal precipitation gradually
tapering off from north to south, including some isolated
thunderstorms. Otherwise, colder air to filter into the region and
with plenty of cloud cover and rain, temperatures will only rise
into the upper 60s to mid 70s.
Dry and colder weather to prevail through the weekend. Could see a
stray shower on Saturday as decent shortwave energy rotates around
upper level trof that is anchored over the Great Lakes. For now have
dry conditions, but will need to keep an eye on the models as we get
closer to this time period.
By Sunday night surface ridge will begin to move off to the
southeast. This will allow southerly winds to return once again and
temperatures moderate back into the 80s by Tuesday.
Extended models hinting at another cold front moving through region
beginning Wednesday night. Have low chance pops Wednesday night and
Thursday.
Byrd
&&
.AVIATION: (For the 18z TAFs through 18z Friday Afternoon)
Issued at 1255 PM CDT Thu Sep 10 2015
SCT to occasionally BKN CU field with bases aoa 4kft expected
across the FA this afternoon. There appears to be two areas of
potential convection for this afternoon...one is associated with
weak convergence along cold front/surface trof that will be
drifting into the KUIN area this afternoon, and have maintained
VCTS for several hours in KUIN TAF in the late afternoon and early
evening hours for this threat. Second area is isolated/AMS-type
convection forming ahead of shortwave now entering STL Metro. Have
maintained a dry forecast at all metro area TAFs for now, but
getting a few cells forming to the NW of the area, and if they
hold together/intensify may need to nowcast this threat into some
of the metro TAFS.
However, still believe the primary threat of convection during
this TAF period will be late this evening and overnight, as
discussed in Short-term AFD update. Like the trends suggested by
the 15z HRRR, and have trended onset of precip and potential
thunderstorm activity based on this output. Both NAM and GFS MOS
suggest cigs lowering to IFR in the primary rain area along and
I-70 corridor during the predawn hours...haven`t gone quite this
low, but given time of year and post-frontal cool air...low end
MVFR certainly seems reasonable.
Specifics for KSTL: Scattered CU with bases aoa 4kft expected this
afternoon. AMS-type storms will dot the area, but will isolated
coverage will monitor their trends and use nowcast techniques to
determine if these will impact TAF area. Much larger of area of
rain and embedded thunderstorms expected to work into the area
after 06z, with ceilings in the stratus and rain deteriorating to
low-end MVFR by daybreak Friday.
Truett
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS SPRINGFIELD MO
1237 PM CDT THU SEP 10 2015
.MESOSCALE DISCUSSION...
Issued at 1150 AM CDT THU SEP 10 2015
Convection that faded as it moved into the Ozarks this morning
has left a few boundaries across the the region that can be seen
in the visible satellite imagery. The most notable were one along
the I-49 corridor across western Missouri and another that
stretched from southeastern Barry to central Dent Counties.
Instability across the western half of the Ozarks, generally west
of the highway 65 corridor was showing from 1400-1800 j/kg with
the best instability across eastern Kansas. There was little CINH
noted along I-49 and west into Southeastern Kansas. With this
combination of instability, low CINH and residual boundaries it
will be possible for storm development this afternoon with the
primary area of potential convection expected mainly along and
west of I-49.
Development may begin over the next few hours as noted on short
term mesoscale models. This development would likely diminish once
the sun goes down and daytime heating subsides, which would allow
the airmass to recharge ahead of the cold front that is expected
to move through the region during the overnight hours.
&&
.UPDATE...
Issued at 0540 AM CDT THU SEP 10 2015
A small convective complex near Kansas City has thus far refused
to die this morning, despite the loss of nearly all of its low
level jet support. With the HRRR now suggesting that this complex
may well hold together into southern Missouri, have gone ahead and
added PoPs along it`s expected path, which for now is from roughly
Clinton to Springfield. Trends will be monitored with additional
adjustments to PoPs likely over the next few hours.
&&
.SHORT TERM...(Today and Tonight)
Issued at 0240 AM CDT THU SEP 10 2015
This morning is starting out rather mild across the region, with
temperatures at 2 AM generally in the mid to upper 60s. Despite
ample low level moisture and T/Td spreads of only a degree or two,
fog has been slow to form so far, likely due to the presence of
very light southerly winds, and the approach of scattered cirrus
from the northwest. That said, I do think there is still the
potential for fog to form through sunrise, though it may not end
up being quite as widespread as initially thought.
Light south to southwest winds and high cloud cover can be
expected today, with temperatures warming into the low to mid 80s
by this afternoon.
A cold front currently located across the Great Lakes and northern
Plains will sharpen and accelerate south this evening into
tonight, and pass through the forecast area from north to south
during the overnight hours into Friday morning. Initial convection
near the KC area late this afternoon may be strong to severe, and
we will need to watch for the potential for a few of the stronger
storms to move into the northwestern corner of the CWA tonight.
For most of the forecast area, however, it appears that
instability will be low enough to preclude widespread severe
weather with this system. Gusty 40-50 MPH winds will still be
possible late tonight as convection moves through the area,
however.
.LONG TERM...(Friday through Wednesday)
Issued at 0240 AM CDT THU SEP 10 2015
The front should clear the area by mid day Friday, with a much
cooler and drier airmass quickly building into the area. A few
lingering showers/storms will be possible over far southern/south
central Missouri early Friday, but dry weather is expected for
most. Right now, it appears that highs on Friday may only reach
the low to perhaps mid 70s, with dewpoints quickly falling into
the low 50s by afternoon.
Even cooler conditions are then expected Friday night through
Sunday, with low temperatures around 50 Saturday morning, and
Sunday morning lows dropping into the 40s for most! Highs on
Saturday and Sunday will be in the upper 60s to around 70
degrees, some 10-15 degrees below average.
Expansive high pressure will continue to build across the
Southeastern U.S. through the early part of next workweek. This
will eventually result in southerly return flow across the Ozarks
by Tuesday and Wednesday, with temperatures (and dewpoints)
increasing back to or above normal values. The increase in
temperatures and humidity should result in a corresponding
increase in thunderstorm potential by the middle of next week.
&&
.AVIATION...(For the 18Z TAFS through 18Z Friday Afternoon)
Issued at 1234 PM CDT THU SEP 10 2015
Aviators flying into the Ozarks over the next 24 hour will need
to monitor for isolated to scattered afternoon convection
developing across the region this afternoon through sunset.
several boundaries may allow storms to focus over portions of the
region that will affect the regions aerodromes. Storms that
develop this afternoon will remain scattered in nature. The
primary concern will come during the overnight hours as a cold
front moves through the region. winds will shift from southerly
to northwesterly as the front passes. During the frontal passage
and behind it, ceilings will fall from MVFR to IFR with
visibilities variable from VFR to IFR with rainfall and frontal
passage.
The front should be through most of the Ozarks by mid day Friday
with slowly improving flight conditions through the remainder of
the day.
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
MESOSCALE...Hatch
UPDATE...Boxell
SHORT TERM...Boxell
LONG TERM...Boxell
AVIATION...Hatch
AREA FORECAST DISCUSSION
NWS SPRINGFIELD MO
1208 PM CDT THU SEP 10 2015
.MESOSCALE DISCUSSION...
Issued at 1150 AM CDT THU SEP 10 2015
Convection that faded as it moved into the Ozarks this morning
has left a few boundaries across the the region that can be seen
in the visible satellite imagery. The most notable were one along
the I-49 corridor across western Missouri and another that
stretched from southeastern Barry to central Dent Counties.
Intability across the western half of the Ozarks, generally west
of the highway 65 corridor was showing from 1400-1800 j/kg with
the best instability across eastern Kansas. There was little CINH
noted along I-49 and west into Southeastern Kansas. With this
combination of instability, low CINH and residual boundaries it
will be possible for storm development this afternoon with the
primary area of potential convection expected maily along and
west of I-49.
Development may begin over the next few hours as noted on short
term mesoscale models. This development would likely diminish once
the sun goes down and daytime heating subsides, which would allow
the airmass to recharge ahead of the cold front that is expected
to move through the region during the overnight hours.
&&
.UPDATE...
Issued at 0540 AM CDT THU SEP 10 2015
A small convective complex near Kansas City has thus far refused
to die this morning, despite the loss of nearly all of its low
level jet support. With the HRRR now suggesting that this complex
may well hold together into southern Missouri, have gone ahead and
added PoPs along it`s expected path, which for now is from roughly
Clinton to Springfield. Trends will be monitored with additional
adjustments to PoPs likely over the next few hours.
&&
.SHORT TERM...(Today and Tonight)
Issued at 0240 AM CDT THU SEP 10 2015
This morning is starting out rather mild across the region, with
temperatures at 2 AM generally in the mid to upper 60s. Despite
ample low level moisture and T/Td spreads of only a degree or two,
fog has been slow to form so far, likely due to the presence of
very light southerly winds, and the approach of scattered cirrus
from the northwest. That said, I do think there is still the
potential for fog to form through sunrise, though it may not end
up being quite as widespread as initially thought.
Light south to southwest winds and high cloud cover can be
expected today, with temperatures warming into the low to mid 80s
by this afternoon.
A cold front currently located across the Great Lakes and northern
Plains will sharpen and accelerate south this evening into
tonight, and pass through the forecast area from north to south
during the overnight hours into Friday morning. Initial convection
near the KC area late this afternoon may be strong to severe, and
we will need to watch for the potential for a few of the stronger
storms to move into the northwestern corner of the CWA tonight.
For most of the forecast area, however, it appears that
instability will be low enough to preclude widespread severe
weather with this system. Gusty 40-50 MPH winds will still be
possible late tonight as convection moves through the area,
however.
.LONG TERM...(Friday through Wednesday)
Issued at 0240 AM CDT THU SEP 10 2015
The front should clear the area by mid day Friday, with a much
cooler and drier airmass quickly building into the area. A few
lingering showers/storms will be possible over far southern/south
central Missouri early Friday, but dry weather is expected for
most. Right now, it appears that highs on Friday may only reach
the low to perhaps mid 70s, with dewpoints quickly falling into
the low 50s by afternoon.
Even cooler conditions are then expected Friday night through
Sunday, with low temperatures around 50 Saturday morning, and
Sunday morning lows dropping into the 40s for most! Highs on
Saturday and Sunday will be in the upper 60s to around 70
degrees, some 10-15 degrees below average.
Expansive high pressure will continue to build across the
Southeastern U.S. through the early part of next workweek. This
will eventually result in southerly return flow across the Ozarks
by Tuesday and Wednesday, with temperatures (and dewpoints)
increasing back to or above normal values. The increase in
temperatures and humidity should result in a corresponding
increase in thunderstorm potential by the middle of next week.
&&
.AVIATION...(For the 12Z TAFS through 12Z Friday Morning)
Issued at 0623 AM CDT THU SEP 10 2015
With a weakening cluster of storms dropping southeast from Kansas
City this morning, went ahead and included tempo group for storms
around mid morning at Springfield and Joplin. Otherwise, will
bring in another vicinity/tempo group for afternoon convective
potential with approaching front/shortwave trough. Expect a wind
shift from south to northwest should occur between 04z and 08z
as the front drops quickly south of the MO border.
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
MESOSCALE...Hatch
UPDATE...Boxell
SHORT TERM...Boxell
LONG TERM...Boxell
AVIATION...Terry
AREA FORECAST DISCUSSION
NWS SPRINGFIELD MO
633 AM CDT THU SEP 10 2015
.UPDATE...
Issued at 0540 AM CDT THU SEP 10 2015
A small convective complex near Kansas City has thus far refused
to die this morning, despite the loss of nearly all of its low
level jet support. With the HRRR now suggesting that this complex
may well hold together into southern Missouri, have gone ahead and
added PoPs along it`s expected path, which for now is from roughly
Clinton to Springfield. Trends will be monitored with additional
adjustments to PoPs likely over the next few hours.
&&
.SHORT TERM...(Today and Tonight)
Issued at 0240 AM CDT THU SEP 10 2015
This morning is starting out rather mild across the region, with
temperatures at 2 AM generally in the mid to upper 60s. Despite
ample low level moisture and T/Td spreads of only a degree or two,
fog has been slow to form so far, likely due to the presence of
very light southerly winds, and the approach of scattered cirrus
from the northwest. That said, I do think there is still the
potential for fog to form through sunrise, though it may not end
up being quite as widespread as initially thought.
Light south to southwest winds and high cloud cover can be
expected today, with temperatures warming into the low to mid 80s
by this afternoon.
A cold front currently located across the Great Lakes and northern
Plains will sharpen and accelerate south this evening into
tonight, and pass through the forecast area from north to south
during the overnight hours into Friday morning. Initial convection
near the KC area late this afternoon may be strong to severe, and
we will need to watch for the potential for a few of the stronger
storms to move into the northwestern corner of the CWA tonight.
For most of the forecast area, however, it appears that
instability will be low enough to preclude widespread severe
weather with this system. Gusty 40-50 MPH winds will still be
possible late tonight as convection moves through the area,
however.
.LONG TERM...(Friday through Wednesday)
Issued at 0240 AM CDT THU SEP 10 2015
The front should clear the area by mid day Friday, with a much
cooler and drier airmass quickly building into the area. A few
lingering showers/storms will be possible over far southern/south
central Missouri early Friday, but dry weather is expected for
most. Right now, it appears that highs on Friday may only reach
the low to perhaps mid 70s, with dewpoints quickly falling into
the low 50s by afternoon.
Even cooler conditions are then expected Friday night through
Sunday, with low temperatures around 50 Saturday morning, and
Sunday morning lows dropping into the 40s for most! Highs on
Saturday and Sunday will be in the upper 60s to around 70
degrees, some 10-15 degrees below average.
Expansive high pressure will continue to build across the
Southeastern U.S. through the early part of next workweek. This
will eventually result in southerly return flow across the Ozarks
by Tuesday and Wednesday, with temperatures (and dewpoints)
increasing back to or above normal values. The increase in
temperatures and humidity should result in a corresponding
increase in thunderstorm potential by the middle of next week.
&&
.AVIATION...(For the 12Z TAFS through 12Z Friday Morning)
Issued at 0623 AM CDT THU SEP 10 2015
With a weakening cluster of storms dropping southeast from Kansas
City this morning, went ahead and included tempo group for storms
around mid morning at Springfield and Joplin. Otherwise, will
bring in another vicinity/tempo group for afternoon convective
potential with approaching front/shortwave trough. Expect a wind
shift from south to northwest should occur between 04z and 08z
as the front drops quickly south of the MO border.
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
UPDATE...Boxell
SHORT TERM...Boxell
LONG TERM...Boxell
AVIATION...Terry
AREA FORECAST DISCUSSION
NWS SPRINGFIELD MO
540 AM CDT THU SEP 10 2015
.UPDATE...
Issued at 0540 AM CDT THU SEP 10 2015
A small convective complex near Kansas City has thus far refused
to die this morning, despite the loss of nearly all of its low
level jet support. With the HRRR now suggesting that this complex
may well hold together into southern Missouri, have gone ahead and
added PoPs along it`s expected path, which for now is from roughly
Clinton to Springfield. Trends will be monitored with additional
adjustments to PoPs likely over the next few hours.
&&
.SHORT TERM...(Today and Tonight)
Issued at 0240 AM CDT THU SEP 10 2015
This morning is starting out rather mild across the region, with
temperatures at 2 AM generally in the mid to upper 60s. Despite
ample low level moisture and T/Td spreads of only a degree or two,
fog has been slow to form so far, likely due to the presence of
very light southerly winds, and the approach of scattered cirrus
from the northwest. That said, I do think there is still the
potential for fog to form through sunrise, though it may not end
up being quite as widespread as initially thought.
Light south to southwest winds and high cloud cover can be
expected today, with temperatures warming into the low to mid 80s
by this afternoon.
A cold front currently located across the Great Lakes and northern
Plains will sharpen and accelerate south this evening into
tonight, and pass through the forecast area from north to south
during the overnight hours into Friday morning. Initial convection
near the KC area late this afternoon may be strong to severe, and
we will need to watch for the potential for a few of the stronger
storms to move into the northwestern corner of the CWA tonight.
For most of the forecast area, however, it appears that
instability will be low enough to preclude widespread severe
weather with this system. Gusty 40-50 MPH winds will still be
possible late tonight as convection moves through the area,
however.
.LONG TERM...(Friday through Wednesday)
Issued at 0240 AM CDT THU SEP 10 2015
The front should clear the area by mid day Friday, with a much
cooler and drier airmass quickly building into the area. A few
lingering showers/storms will be possible over far southern/south
central Missouri early Friday, but dry weather is expected for
most. Right now, it appears that highs on Friday may only reach
the low to perhaps mid 70s, with dewpoints quickly falling into
the low 50s by afternoon.
Even cooler conditions are then expected Friday night through
Sunday, with low temperatures around 50 Saturday morning, and
Sunday morning lows dropping into the 40s for most! Highs on
Saturday and Sunday will be in the upper 60s to around 70
degrees, some 10-15 degrees below average.
Expansive high pressure will continue to build across the
Southeastern U.S. through the early part of next workweek. This
will eventually result in southerly return flow across the Ozarks
by Tuesday and Wednesday, with temperatures (and dewpoints)
increasing back to or above normal values. The increase in
temperatures and humidity should result in a corresponding
increase in thunderstorm potential by the middle of next week.
&&
.AVIATION...(For the 06Z TAFS through 06Z Thursday Night)
Issued at 1142 PM CDT WED SEP 09 2015
The combination of surface high pressure...light winds...and
residual low level moisture from the rainfall over the last
couple of days should be enough to bring on some fog overnight.
Several locations across the region are already in the 5-7SM
range at this hour. Expect visibilities to continue to fall
overnight. Will drop KSGF/KJLN down to 2SM with TEMPO to 1/2SM FG
while dropping KBBG to 1/4SM FG in roughly the 09-12z time frame.
Fog should begin to dissipate after sunrise with conditions
returning to VFR by around 15z. Next challenge then becomes
convection towards the end of the forecast period. Expect TSRA to
begin developing/moving in after 03z...so will add VCTS for
KSGF/KJLN after that time. For now...will leave out of KBBG as
believe convection will not affect that terminal until after the
end of the forecast period.
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
UPDATE...Boxell
SHORT TERM...Boxell
LONG TERM...Boxell
AVIATION...Gaede
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
926 AM MDT THU SEP 10 2015
.UPDATE...
CURRENT FORECAST IS IN GOOD SHAPE WITH JUST A MINOR ADJUSTMENT MADE
WITH THIS UPDATE. SATELLITE IS SHOWING A WEAK DISTURBANCE MOVING
ACROSS SOUTHEAST MONTANA THIS MORNING. OBSERVATIONS SHOW MAINLY
HIGH CLOUD DECKS SO I REPLACED THE SHOWER WORDING WITH A CHANCE
FOR SPRINKLES. CLOUDS ARE BREAKING UP ACROSS THE NORTH SO POPS
HAVE BEEN SCALED BACK TO JUST OUR FAR SOUTHEAST COUNTIES AND
SHERIDAN COUNTY. SKIES HAVE BECOME MOSTLY SUNNY ACROSS OUR WEST.
EXPECT A PARTLY TO MOSTLY SUNNY DAY ACROSS THE WESTERN THIRD OF
OUR AREA WITH DECREASING CLOUDS AND PARTLY SUNNY SKIES THIS
AFTERNOON ACROSS OUR SOUTHEAST. TEMPERATURES WILL BE JUST A FEW
DEGREES COOLER THAN YESTERDAY WITH READINGS ABOUT NORMAL FOR THIS
TIME OF YEAR. HOOLEY
&&
.SHORT TERM...VALID FOR TDY AND FRI...
SEASONABLY WARM TEMPERATURES...LIGHT WINDS AND MAINLY DRY WEATHER
WILL CONTINUE TODAY AND FRIDAY.
TODAY...WE HAVE LINGERED A LOW-END SHOWER CHANCE OVER SOUTHEASTERN
MT THROUGH NOON MDT...AND WE DID DECIDE TO PULL THAT SLIGHT CHANCE
OF SHOWERS BACK SOUTHWEST INTO THE SHERIDAN AREA TOO. THAT WAS ALL
BASED ON OVERNIGHT RADAR TRENDS AS OF 0830 UTC AND RECENT RUNS OF
THE EXPERIMENTAL AND OPERATIONAL HRRR MODEL. THE SHORTWAVE TROUGH
RESPONSIBLE FOR THE EARLY-DAY SHOWER CHANCE WILL MOVE SOUTHEAST OF
THE AREA BY AFTERNOON AND SO WE DECIDED TO GO WITH A DRY FORECAST
EVERYWHERE AFTER 18 UTC EVEN THOUGH WE CANNOT ENTIRELY RULE OUT A
SPRINKLE IN SOUTHEASTERN MT THIS AFTERNOON. FORECAST HIGHS TODAY
WERE DRIVEN BY THE 00 UTC MULTI-MODEL CONSENSUS...AND ARE MAINLY
IN THE 70S F ON RELATIVELY LIGHT NORTH-NORTHEAST WINDS.
TONIGHT...THE 00 UTC GUIDANCE SHOWED ANOTHER AND WEAKER SHORTWAVE
TROUGH CROSSING SOUTHEASTERN MT IN NORTHWEST FLOW ALOFT DURING THE
EVENING. HOWEVER...WE CHOSE TO STAY WITH A DRY FORECAST FOR NOW AS
THE QG-FORCING WITH THE WAVE IS WEAK...THERE/S VERY LITTLE QPF IN
MODEL SIMULATIONS...AND MOS-BASED POPS ARE ALL BELOW 15 PERCENT.
WE THUS EXPECT A QUIET NIGHT WITH LOWS MAINLY IN THE 40S F ACROSS
THE AREA AS SURFACE HIGH PRESSURE SLIDES SOUTH ACROSS THE DAKOTAS.
FRIDAY...FLOW ALOFT WILL TURN DECIDEDLY ANTI-CYCLONIC AS A 500-MB
RIDGE OVER THE WESTERN UNITED STATES BUILDS EASTWARD. THE AIR MASS
WILL WARM AS A RESULT AND THUS TEMPERATURES WILL BE A BIT WARMER
THAN TODAY. SOME AREAS WILL LIKELY BE NEAR 80 F IN SOUTH CENTRAL
MT AND NORTH CENTRAL WY...BUT FORECAST SOUNDINGS SUGGEST MIXING
MAY BE SOMEWHAT LIMITED BY A SUBSIDENCE INVERSION JUST ABOVE 700
MB. WE RELIED ON THE 00 UTC MULTI-MODEL CONSENSUS FOR HIGHS GIVEN
THIS SCENARIO AND LITTLE SPREAD IN GUIDANCE OUTPUT. SCHULTZ
.LONG TERM...VALID FOR SAT...SUN...MON...TUE...WED...
PATTERN CONTINUES TO LOOK WARM TO START...COOLER TO FINISH. AN
UPPER RIDGE WILL BUILD SATURDAY AND GET FLATTENED OUT BY ENERGY
RIDING ACROSS SOUTHERN CANADA ON SUNDAY. BACKING FLOW WITH
LOWERING HEIGHTS ON TAP FOR SUNDAY...BUT DESPITE THIS...BUMPED UP
FORECAST HIGHS. DOWNSLOPE FLOW WILL BE INCREASING WITH STRONGER
700MB WINDS IN A PRE FRONTAL ENVIRONMENT. RAISED HIGHS ON SUNDAY
TO MATCH THOSE OF SATURDAY. A COLD FRONT WILL PUSH THROUGH THE
AREA SUNDAY EVENING AND PROVIDE A COOLER DAY MONDAY.
MODELS THEN DIVERGE FROM TUESDAY ONWARD AND THE DIFFERENCES STEM
FROM THE DEVELOPING WESTERN TROUGH. THE GFS WAS STRONGER WITH THE
SOUTHERN STREAM ENERGY OF THE TROUGH AND THEREFORE DEEPER WITH IT
IN THE GREAT BASIN. THE ECMWF SWEEPS THE STRONGER ENERGY NORTH AND
WAS FLATTER WITH THE SOUTHERN EXTENT OF THE TROUGH FOR WARMER AND
DRIER WEATHER FOR TUESDAY. SINCE BOTH MODELS HIT THE AREA...IN
PARTICULAR THE WEST...WITH QPF...RAISED POPS FOR TUESDAY AND
TUESDAY NIGHT. DIFFERENCES EXIST FOR WEDNESDAY AS THE GFS WAS
WARMER AND DRIER WITH ZONAL FLOW...WHILE THE ECMWF MAINTAINS A
SOUTHWEST FLOW AND SENDS ENERGY UP FOR CHANCE POPS. TWH
&&
.AVIATION...
A FAIRLY QUIET WEATHER PATTERN WILL REMAIN IN PLACE WITH VFR
FLYING CONDITIONS EXPECTED. A WEAK DISTURBANCE WILL CREATE A FEW
SPRINKLES OR SOME VIRGA OVER SOUTHEAST MONTANA AND NORTHEAST
WYOMING THIS MORNING. OTHERWISE...NO PRECIPITATION EXPECTED WITH
CLOUDS BASES ABOVE 10 THOUSAND FEET. WINDS WILL BE LIGHT. TWH
&&
.PRELIMINARY POINT TEMP/POPS...
TDY FRI SAT SUN MON TUE WED
-------------------------------------------------------
BIL 075 049/079 051/090 057/090 055/076 052/069 042/066
1/B 00/U 00/U 00/U 12/T 33/T 32/W
LVM 077 043/081 045/088 051/088 050/076 045/063 042/063
0/B 00/U 00/U 11/U 12/T 33/T 32/W
HDN 077 047/080 049/090 055/090 054/079 051/073 042/068
1/B 00/U 00/U 00/U 12/T 23/T 32/W
MLS 074 047/076 049/088 057/088 055/078 050/072 046/067
1/B 10/U 00/U 00/U 12/T 22/T 32/W
4BQ 073 047/075 049/086 056/089 056/080 051/073 049/070
2/W 10/U 00/U 00/U 11/B 22/T 42/W
BHK 070 045/072 046/083 053/086 053/078 049/073 048/067
1/B 10/U 00/U 00/U 12/T 22/T 32/W
SHR 076 044/078 045/087 050/088 051/080 048/073 044/069
2/W 10/U 00/U 00/U 12/T 23/T 41/B
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS BILLINGS MT
243 AM MDT THU SEP 10 2015
.SHORT TERM...VALID FOR TDY AND FRI...
SEASONABLY WARM TEMPERATURES...LIGHT WINDS AND MAINLY DRY WEATHER
WILL CONTINUE TODAY AND FRIDAY.
TODAY...WE HAVE LINGERED A LOW-END SHOWER CHANCE OVER SOUTHEASTERN
MT THROUGH NOON MDT...AND WE DID DECIDE TO PULL THAT SLIGHT CHANCE
OF SHOWERS BACK SOUTHWEST INTO THE SHERIDAN AREA TOO. THAT WAS ALL
BASED ON OVERNIGHT RADAR TRENDS AS OF 0830 UTC AND RECENT RUNS OF
THE EXPERIMENTAL AND OPERATIONAL HRRR MODEL. THE SHORTWAVE TROUGH
RESPONSIBLE FOR THE EARLY-DAY SHOWER CHANCE WILL MOVE SOUTHEAST OF
THE AREA BY AFTERNOON AND SO WE DECIDED TO GO WITH A DRY FORECAST
EVERYWHERE AFTER 18 UTC EVEN THOUGH WE CANNOT ENTIRELY RULE OUT A
SPRINKLE IN SOUTHEASTERN MT THIS AFTERNOON. FORECAST HIGHS TODAY
WERE DRIVEN BY THE 00 UTC MULTI-MODEL CONSENSUS...AND ARE MAINLY
IN THE 70S F ON RELATIVELY LIGHT NORTH-NORTHEAST WINDS.
TONIGHT...THE 00 UTC GUIDANCE SHOWED ANOTHER AND WEAKER SHORTWAVE
TROUGH CROSSING SOUTHEASTERN MT IN NORTHWEST FLOW ALOFT DURING THE
EVENING. HOWEVER...WE CHOSE TO STAY WITH A DRY FORECAST FOR NOW AS
THE QG-FORCING WITH THE WAVE IS WEAK...THERE/S VERY LITTLE QPF IN
MODEL SIMULATIONS...AND MOS-BASED POPS ARE ALL BELOW 15 PERCENT.
WE THUS EXPECT A QUIET NIGHT WITH LOWS MAINLY IN THE 40S F ACROSS
THE AREA AS SURFACE HIGH PRESSURE SLIDES SOUTH ACROSS THE DAKOTAS.
FRIDAY...FLOW ALOFT WILL TURN DECIDEDLY ANTI-CYCLONIC AS A 500-MB
RIDGE OVER THE WESTERN UNITED STATES BUILDS EASTWARD. THE AIR MASS
WILL WARM AS A RESULT AND THUS TEMPERATURES WILL BE A BIT WARMER
THAN TODAY. SOME AREAS WILL LIKELY BE NEAR 80 F IN SOUTH CENTRAL
MT AND NORTH CENTRAL WY...BUT FORECAST SOUNDINGS SUGGEST MIXING
MAY BE SOMEWHAT LIMITED BY A SUBSIDENCE INVERSION JUST ABOVE 700
MB. WE RELIED ON THE 00 UTC MULTI-MODEL CONSENSUS FOR HIGHS GIVEN
THIS SCENARIO AND LITTLE SPREAD IN GUIDANCE OUTPUT. SCHULTZ
.LONG TERM...VALID FOR SAT...SUN...MON...TUE...WED...
PATTERN CONTINUES TO LOOK WARM TO START...COOLER TO FINISH. AN
UPPER RIDGE WILL BUILD SATURDAY AND GET FLATTENED OUT BY ENERGY
RIDING ACROSS SOUTHERN CANADA ON SUNDAY. BACKING FLOW WITH
LOWERING HEIGHTS ON TAP FOR SUNDAY...BUT DESPITE THIS...BUMPED UP
FORECAST HIGHS. DOWNSLOPE FLOW WILL BE INCREASING WITH STRONGER
700MB WINDS IN A PRE FRONTAL ENVIRONMENT. RAISED HIGHS ON SUNDAY
TO MATCH THOSE OF SATURDAY. A COLD FRONT WILL PUSH THROUGH THE
AREA SUNDAY EVENING AND PROVIDE A COOLER DAY MONDAY.
MODELS THEN DIVERGE FROM TUESDAY ONWARD AND THE DIFFERENCES STEM
FROM THE DEVELOPING WESTERN TROUGH. THE GFS WAS STRONGER WITH THE
SOUTHERN STREAM ENERGY OF THE TROUGH AND THEREFORE DEEPER WITH IT
IN THE GREAT BASIN. THE ECMWF SWEEPS THE STRONGER ENERGY NORTH AND
WAS FLATTER WITH THE SOUTHERN EXTENT OF THE TROUGH FOR WARMER AND
DRIER WEATHER FOR TUESDAY. SINCE BOTH MODELS HIT THE AREA...IN
PARTICULAR THE WEST...WITH QPF...RAISED POPS FOR TUESDAY AND
TUESDAY NIGHT. DIFFERENCES EXIST FOR WEDNESDAY AS THE GFS WAS
WARMER AND DRIER WITH ZONAL FLOW...WHILE THE ECMWF MAINTAINS A
SOUTHWEST FLOW AND SENDS ENERGY UP FOR CHANCE POPS. TWH
&&
.AVIATION...
A FAIRLY QUIET WEATHER PATTERN WILL REMAIN IN PLACE WITH VFR
FLYING CONDITIONS EXPECTED. A WEAK DISTURBANCE WILL CREATE A FEW
SPRINKLES OR SOME VIRGA OVER SOUTHEAST MONTANA AND NORTHEAST
WYOMING THIS MORNING. OTHERWISE...NO PRECIPITATION EXPECTED WITH
CLOUDS BASES ABOVE 10 THOUSAND FEET. WINDS WILL BE LIGHT. TWH
&&
.PRELIMINARY POINT TEMP/POPS...
TDY FRI SAT SUN MON TUE WED
-------------------------------------------------------
BIL 075 049/079 051/090 057/090 055/076 052/069 042/066
1/B 00/U 00/U 00/U 12/T 33/T 32/W
LVM 077 043/081 045/088 051/088 050/076 045/063 042/063
0/B 00/U 00/U 11/U 12/T 33/T 32/W
HDN 077 047/080 049/090 055/090 054/079 051/073 042/068
1/B 00/U 00/U 00/U 12/T 23/T 32/W
MLS 074 047/076 049/088 057/088 055/078 050/072 046/067
2/W 10/U 00/U 00/U 12/T 22/T 32/W
4BQ 073 047/075 049/086 056/089 056/080 051/073 049/070
2/W 10/U 00/U 00/U 11/B 22/T 42/W
BHK 070 045/072 046/083 053/086 053/078 049/073 048/067
2/W 10/U 00/U 00/U 12/T 22/T 32/W
SHR 076 044/078 045/087 050/088 051/080 048/073 044/069
2/W 10/U 00/U 00/U 12/T 23/T 41/B
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
324 PM CDT THU SEP 10 2015
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 323 PM CDT THU SEP 10 2015
STRONG TO LOCALLY SEVERE THUNDERSTORMS ARE THE PRIMARY CONCERN GOING
IN THE NEAR TERM...WITH THE MAIN THREAT AREA FOR SEVERE WEATHER
MAINLY ACROSS OUR FAR SOUTHEASTERN ZONES. LARGE SCALE FORCING IN
ASSOCIATION WITH NORTHERN PLAINS IMPULSE HAS ALREADY SPARKED OFF
SHOWERS AND A FEW STRONG THUNDERSTORMS THIS AFTERNOON. DEVELOPMENT
HAVE BEEN NOTICED ACROSS OUR NORTHERN ZONES WHERE THE ATMOSPHERE IS
CHARACTERIZED AS WEAKLY UNSTABLE. A SECOND AREA OF DEVELOPMENT
APPEARS TO BE ALONG A MID-LEVEL FRONT ACROSS SOUTHEASTERN CUSTER
COUNTY WEST INTO THE SANDHILLS AND THE THIRD IS ACROSS FAR SOUTHWEST
NEBRASKA /EAST OF MCK/. THIS DEVELOPMENT IS FOCUSING ALONG A DRY
LINE.
WILL NEED TO MONITOR OUR SOUTHEASTERN ZONES AS THEY LIE IN A
FAVORABLE REGION FOR SUPERCELL DEVELOPMENT. MESOANALYSIS FROM
ACROSS OUR SOUTHEASTERN ZONES REVEALS AMPLE INSTABILITY...WITH
SBCAPES ESTIMATED AT 3500 J/KG WITH FAVORABLE INCREASING/VEERING
WINDS ALOFT ACROSS MUCH OF FRONTIER COUNTY. THE SPC SIGNIFICANT HAIL
PARAMETER INDICATES A BULLSEYE OF 3 ALONG THE LINCOLN/FRONTIER
COUNTY LINE AND A 2 OVER MUCH OF OUR SOUTHEASTERN ZONES. THE
SUPERCELL COMPOSITE GENERALLY FAVORS THE SAME AREA. LARGE HAIL IS
THE PRIMARY CONCERN WHERE STORMS FORM ACROSS OUR SOUTHEASTERN ZONES.
LATEST HRRR GUIDANCE IS PICKED UP ON THE SB CONVECTION ACROSS OUR
FAR SOUTHEASTERN ZONES WELL IN PREVIOUS RUNS...BUT LARGELY IGNORED
THE MID-LEVEL FRONT /ELEVATED CONVECTION OVER THE SANDHILLS EAST
THROUGH CUSTER COUNTY/ UNTIL THE MOST RECENT RUN. THE MODEL HAS
BEEN STEADY THOUGH SUGGESTING THE POTENTIAL SEVERE ACTIVITY
SOUTHEAST OF THE FORECAST AREA SHORTLY AFTER 22Z. FOR THE NORTHERN
SHOWERS AND WEAK STORMS...THE FORCING WILL QUICKLY SHIFT EAST THIS
EVENING...WITH THE SHOWERS EXPECTED TO BE OVER BY MID-EVENING.
POST FRONTAL CONDITIONS WILL PROVIDE FOR A DRY AND COOL DAY ACROSS
THE CENTRAL PLAINS ON FRIDAY. HIGHS ARE FORECAST TO WARM INTO THE
60S TO LOWER 70S ACROSS THE FORECAST AREA.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 323 PM CDT THU SEP 10 2015
FOR FRIDAY NIGHT AND SATURDAY...AN AMPLIFIED NWRLY FLOW ALOFT WITH
A RETURN OF SOUTHERLY WINDS WITH HIGHS WARMING TO THE LOWER 80S
ACROSS THE WEST WHILE THE EAST REMAINS IN THE LOWER TO MID 70S.
ON SUNDAY...A BROAD TROUGH WILL EXTEND WEST TO EAST ACROSS CANADA
WITH FAIRLY ZONAL FLOW ACROSS THE NRN CONUS. THIS WILL BRING A
THERMAL RIDGE EASTWARD INTO THE PLAINS AS H85 TEMPS IN WRN NEBR
REACH 25 TO 30C. HIGHS WERE NUDGED UPWARD TO NEAR 90 WEST.
FOR MONDAY THROUGH THURSDAY...ABOVE NORMAL TEMPERATURES. UPPER
FLOW WILL BECOME SOUTHWESTERLY ALOFT MONDAY AND TUESDAY AS AN
UPPER TROUGH DIGS INTO THE NWRN CONUS. THIS WILL ACT TO EXPAND
THE THERMAL RIDGE EASTWARD ACROSS THE CENTRAL PLAINS. HIGHS AGAIN
NUDGED UPWARD TO THE UPPER 8OS TO AROUND 90 MOST AREAS THESE HIGHS
WILL BE 10 TO 15 DEGREES ABOVE NORMAL.
A COLD FRONT TUESDAY NIGHT TO BRING A SLIGHT CHC FOR SHOWERS AND
THUNDERSTORMS. EXTENDED PROCEDURE KEEPS WEDNESDAY DRY EXCEPT A
SLIGHT CHANCE IN THE NORTHEASTERN AREAS. FUTURE MODEL RUNS MAY
SHOW BETTER SUPPORT FOR WEDNESDAY AND WEDNESDAY NIGHT. BEHIND THE
FRONT....HIGHS COOL BACK SOME TO THE UPPER 70S NORTH AND LOWER 80S
NORTH FOR WEDNESDAY AND THURSDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1232 PM CDT THU SEP 10 2015
THE FORECAST CALLS FOR A SLIGHT CHANCE OF SHOWERS AND/OR
THUNDERSTORMS AT BOTH THE LBF AND VTN TERMINALS THROUGH THIS
EVENING...HOWEVER THE GREATEST OPPORTUNITY OF A STRONG OR SEVERE
STORM WILL LIE TO THE SOUTHEAST OF THE LBF TERMINAL. THE MOST
RECENT NEAR TERM CONVECTIVE ALLOWING MODEL RUN DOES GENERATE
STORMS AFTER 21Z THIS AFTERNOON SOUTH OF INTERSTATE 80 AND EAST OF
HIGHWAY 83...SO THE TRENDS WILL BE MONITORED CLOSELY FOR LBF. THE
ACTIVITY WILL SHIFT QUICKLY OFF TO THE SOUTHEAST...WITH ANY
POTENTIAL CONVECTION WELL SOUTHEAST OF THE TERMINAL BEFORE 00Z.
AT VTN...AN UPPER LEVEL DISTURBANCE MAY SPARK OFF A SHOWER THROUGH
THIS EVENING...BUT THE COVERAGE DOES NOT WARRANT A MENTION IN THE
TAF FOR NOW. OTHERWISE GUIDANCE INDICATES A RETURN OF LOWER
VISIBILITY AT LBF AFTER 09Z FRIDAY...BUT THIS WAS DISCOUNTED AS AN
OVERCAST DECK AOA 12K FT AGL IS ANTICIPATED.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...JACOBS
LONG TERM...ROBERG
AVIATION...JACOBS
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
203 AM CDT THU SEP 10 2015
.SYNOPSIS...
ISSUED AT 302 PM CDT WED SEP 9 2015
AS OF WEDNESDAY AFTERNOON THE UPPER AIR SYNOPTIC PATTERN OVER THE
CONTINUED TO BE HIGHLIGHTED BY A BROAD TROUGH ASSOCIATED WITH A LOW
SLOWLY MOVING TOWARD HUDSON BAY. THIS HAS THE NORTHERN AND CENTRAL
PLAINS IN RELATIVELY FAST NORTHWEST FLOW ALOFT. COOLER AIR IN THE
MID TO UPPER LEVEL OF THIS FLOW FOSTERED AN ENVIRONMENT
CHARACTERIZED BY STEEP LAPSE RATES AND ELEVATED INSTABILITY...WHICH
HAS AIDED IN THE FORMATION AND PERSISTENCE OF ISOLATED TO SCATTERED
THUNDERSTORM ACTIVITY IN CENTRAL NEBRASKA LATE IN THE MORNING AND
EARLY THIS AFTERNOON. AT THE SURFACE...A WEAK FRONT WAS SLOWLY
MOVING EAST ACROSS THE CWA. AS OF 20Z THE FRONT EXTENDED FROM JUST
EAST OF IMPERIAL AND NORTH PLATTE...NORTHEASTWARD TO NEAR AINSWORTH.
DRY WESTERLY WINDS BEHIND THE FRONT HAD DEWPOINTS DROPPING INTO THE
30S AND 40S ACROSS THE PANHANDLE AND WESTERN SANDHILLS. AHEAD OF
THE FRONT WINDS WERE SOUTHERLY AND DEWPOINTS REMAINED IN THE UPPER
50S AND 60S...WITH A CU FIELD DEVELOPING AS THE BOUNDARY LAYER
BECOMES MORE UNSTABLE. TEMPERATURES WERE GENERALLY IN THE MID 80S.
&&
.UPDATE...
ISSUED AT 158 AM CDT THU SEP 10 2015
STRATUS DEVELOPING IN THE PLATTE RIVER VALLEY HAS PROMPTED AN
UPDATE TO THE SKY CONDITION IN THE FORECAST FOR LINCOLN COUNTY.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 302 PM CDT WED SEP 9 2015
THUNDERSTORMS IN CENTRAL AND NORTH CENTRAL NEBRASKA SHOULD CONTINUE
TO SLOWLY PUSH EAST THROUGH THE REMAINDER AFTERNOON. CONVECTIVE
ACTIVITY HAS ACCELERATED OVER CENTRAL ROCK AND HOLT COUNTY. SOME
LOCATIONS ARE RECEIVING HEAVY RAINFALL DUE TO TRAINING
STORMS...HOWEVER LATEST FFG IN THIS AREA IS QUITE HIGH. ADDITIONAL
SURFACE BASED SHOWERS AND THUNDERSTORM DEVELOPMENT HAS BEGUN IN FAR
SOUTHWEST NEBRASKA AND NORTHWEST KANSAS ALONG AN EASTWARD
PROGRESSING FRONT. HRRR HAS FAVORED AREAS JUST EAST OF A NORTH
PLATTE TO THEDFORD MUCH OF THE DAY...AND THIS MATCHES UP WELL WITH
THE DEVELOPING CU FIELD ON SATELLITE SO THE FORECAST LOOKS ON TRACK.
UPPER LEVEL FORCING IS TOUGH TO DISCERN SO THE SPATIAL EXTENT OF THE
NEW CONVECTION IS NOT EXPECTED TO BE EXPANSIVE. MLCAPE VALUES 1500
J/KG AND 35-40 KTS DEEP LAYER SHEAR WILL SUPPORT A FEW STRONG TO
SEVERE STORMS...HOWEVER WIDESPREAD SEVERE WEATHER IS NOT EXPECTED.
THUNDERSTORMS PUSH EAST THIS EVENING AND BEGIN TO WANE AFTER DARK
WITH THE LOSS OF HEATING AND INSTABILITY.
WEAK SHORTWAVE TROUGH DIVES SOUTHEAST THROUGH THE AREA OVERNIGHT.
WINDS BECOME EASTERLY AS THE FRONT SLOWLY PUSHES JUST SOUTHEAST OF
THE CWA AND A LEE SIDE SURFACE LOW DEEPENS IN NORTHEAST COLORADO.
THIS WILL ALLOW LOW LEVEL MOISTURE TO CREEP BACK WESTWARD...WITH
ANOTHER ROUND OF FOG/STRATUS POSSIBLE FOR SOUTHWEST INTO CENTRAL
NEBRASKA. DID NOT INCLUDE PATCHY FOG IN THE FORECAST AT THIS TIME
SINCE MODEL GUIDANCE HAS BEEN SOMEWHAT INCONSISTENT WITH COVERAGE
AND SEVERITY OF VISIBILITY RESTRICTIONS. THE MOST FAVORABLE AREAS
FOR LOCALLY DENSE FOG FORMATION WILL LIKELY BE WHERE PRECIPITATION
FALLS LATER THIS EVENING.
AN AREA OF SURFACE HIGH PRESSURE BEGINS TO DROP OUT OF ALBERTA AND
INTO THE NORTHERN PLAINS ON THURSDAY. THIS WILL PUSH TEMPERATURES
DOWN A FEW DEGREES WITH HIGHS RANGING FROM THE LOW 70S TO LOW 80S
ACROSS THE CWA. MODELS ADVERTISE LIGHT QPF LATE IN THE AFTERNOON AS
A MID-LEVEL JET STREAK NOSES INTO THE CENTRAL PLAINS...BUT DID NOT
ADD ANY MENTION OF POPS TO THE SHORT TERM FORECAST JUST YET AS THE
BETTER CHANCES LOOK TO BE AFTER 00Z FRIDAY.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 302 PM CDT WED SEP 9 2015
THE NAM REMAINS IN AGREEMENT WITH CURRENT FORECAST WITH A
DISTURBANCE DROPPING SOUTHEAST FROM SWRN SD INTO WRN NEBR
OVERNIGHT. THE GFS IS FASTER WITH THIS DISTURBANCE AND REMAINS
MOSTLY DRY. THEREFORE KEPT POPS LIMITED TO 20 PERCENT WEST OF A
LINE FROM GORDON THROUGH BROKEN BOW.
KEPT VERY NEAR PREVIOUS HIGHS FRIDAY AS EASTERLY WINDS BECOME
SOUTHEAST BY AFTERNOON AND WEAK WAA WILL NOT KICK IN UNTIL
AFTERNOON. THERE COULD ALSO BE A FEW SHOWERS AND CLOUDINESS
LINGERING AS WELL.
ON SATURDAY...A RETURN SOUTHERLY WIND RETURNS WITH HIGHS WARMING
TO NEAR 80 ACROSS THE WEST WHILE THE EAST REMAINS IN THE LOWER TO
MID 70S.
FOR SUNDAY THROUGH TUESDAY...ABOVE NORMAL TEMPERATURES. ZONAL FLOW
ALOFT ACROSS THE CENTRAL PLAINS SUNDAY WILL PERSIST INTO MONDAY AS
AN UPPER TROUGH DIGS INTO THE PACIFIC NORTHWEST. THIS WILL KEEP A
THERMAL RIDGE ACROSS THE REGION WITH HIGHS RANGING IN THE 80S. ON
TUESDAY...THE UPPER TROUGH WILL ADVANCE ACROSS MONTANA THROUGH
COLORADO WITH STRONG HEATING TO OCCUR IN ADVANCE ACROSS THE
CENTRAL PLAINS. FORECAST HIGH ARE 85 TO 90...ALTHOUGH THE
POTENTIAL IS THERE FOR HIGHS TO EXCEED 90 IN SOME AREAS OF WRN
NEBR. A COLD FRONT TUESDAY NIGHT TO COOL BACK HIGHS TO NEAR 75
NORTH AND NEAR 80 SOUTH. THE 12Z ECMWF HOWEVER IS MUCH WEAKER WITH
THE POST FRONTAL COOLDOWN AND SUGGESTS 80S STILL POSSIBLE. MAINLY
DRY THROUGH THE EXTENDED PERIODS...EXCEPT A SLIGHT CHANCE ERN
PNHDL TUESDAY AFTN...AND MOST AREAS TUESDAY NIGHT. LOOKS DRY
BEHIND THE FRONT FOR WEDNESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 158 AM CDT THU SEP 10 2015
STRATUS IN SOUTHWEST NEBRASKA HAS REDUCED CEILING BELOW 600 FEET
AGL AT LBF. CURRENT INDICATIONS ARE THAT THE STRATUS WILL CONTINUE
AND...WITH EAST WIND JUST OFF OF THE SURFACE...WILL PROBABLY
INCREASE IN COVERAGE. HOWEVER...THE LOWEST DECK MAY LIFT
OCCASIONALLY OR SCATTER TO 600 FEET OR ABOVE THOUGH IT IS UNLIKELY
THAT THE CEILING WILL LIFT TO 1000 FEET AGL OR HIGHER.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SPRINGER
SYNOPSIS...MARTIN
SHORT TERM...MARTIN
LONG TERM...ROBERG
AVIATION...SPRINGER
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1141 PM CDT WED SEP 9 2015
.SYNOPSIS...
ISSUED AT 302 PM CDT WED SEP 9 2015
AS OF WEDNESDAY AFTERNOON THE UPPER AIR SYNOPTIC PATTERN OVER THE
CONTINUED TO BE HIGHLIGHTED BY A BROAD TROUGH ASSOCIATED WITH A LOW
SLOWLY MOVING TOWARD HUDSON BAY. THIS HAS THE NORTHERN AND CENTRAL
PLAINS IN RELATIVELY FAST NORTHWEST FLOW ALOFT. COOLER AIR IN THE
MID TO UPPER LEVEL OF THIS FLOW FOSTERED AN ENVIRONMENT
CHARACTERIZED BY STEEP LAPSE RATES AND ELEVATED INSTABILITY...WHICH
HAS AIDED IN THE FORMATION AND PERSISTENCE OF ISOLATED TO SCATTERED
THUNDERSTORM ACTIVITY IN CENTRAL NEBRASKA LATE IN THE MORNING AND
EARLY THIS AFTERNOON. AT THE SURFACE...A WEAK FRONT WAS SLOWLY
MOVING EAST ACROSS THE CWA. AS OF 20Z THE FRONT EXTENDED FROM JUST
EAST OF IMPERIAL AND NORTH PLATTE...NORTHEASTWARD TO NEAR AINSWORTH.
DRY WESTERLY WINDS BEHIND THE FRONT HAD DEWPOINTS DROPPING INTO THE
30S AND 40S ACROSS THE PANHANDLE AND WESTERN SANDHILLS. AHEAD OF
THE FRONT WINDS WERE SOUTHERLY AND DEWPOINTS REMAINED IN THE UPPER
50S AND 60S...WITH A CU FIELD DEVELOPING AS THE BOUNDARY LAYER
BECOMES MORE UNSTABLE. TEMPERATURES WERE GENERALLY IN THE MID 80S.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 302 PM CDT WED SEP 9 2015
THUNDERSTORMS IN CENTRAL AND NORTH CENTRAL NEBRASKA SHOULD CONTINUE
TO SLOWLY PUSH EAST THROUGH THE REMAINDER AFTERNOON. CONVECTIVE
ACTIVITY HAS ACCELERATED OVER CENTRAL ROCK AND HOLT COUNTY. SOME
LOCATIONS ARE RECEIVING HEAVY RAINFALL DUE TO TRAINING
STORMS...HOWEVER LATEST FFG IN THIS AREA IS QUITE HIGH. ADDITIONAL
SURFACE BASED SHOWERS AND THUNDERSTORM DEVELOPMENT HAS BEGUN IN FAR
SOUTHWEST NEBRASKA AND NORTHWEST KANSAS ALONG AN EASTWARD
PROGRESSING FRONT. HRRR HAS FAVORED AREAS JUST EAST OF A NORTH
PLATTE TO THEDFORD MUCH OF THE DAY...AND THIS MATCHES UP WELL WITH
THE DEVELOPING CU FIELD ON SATELLITE SO THE FORECAST LOOKS ON TRACK.
UPPER LEVEL FORCING IS TOUGH TO DISCERN SO THE SPATIAL EXTENT OF THE
NEW CONVECTION IS NOT EXPECTED TO BE EXPANSIVE. MLCAPE VALUES 1500
J/KG AND 35-40 KTS DEEP LAYER SHEAR WILL SUPPORT A FEW STRONG TO
SEVERE STORMS...HOWEVER WIDESPREAD SEVERE WEATHER IS NOT EXPECTED.
THUNDERSTORMS PUSH EAST THIS EVENING AND BEGIN TO WANE AFTER DARK
WITH THE LOSS OF HEATING AND INSTABILITY.
WEAK SHORTWAVE TROUGH DIVES SOUTHEAST THROUGH THE AREA OVERNIGHT.
WINDS BECOME EASTERLY AS THE FRONT SLOWLY PUSHES JUST SOUTHEAST OF
THE CWA AND A LEE SIDE SURFACE LOW DEEPENS IN NORTHEAST COLORADO.
THIS WILL ALLOW LOW LEVEL MOISTURE TO CREEP BACK WESTWARD...WITH
ANOTHER ROUND OF FOG/STRATUS POSSIBLE FOR SOUTHWEST INTO CENTRAL
NEBRASKA. DID NOT INCLUDE PATCHY FOG IN THE FORECAST AT THIS TIME
SINCE MODEL GUIDANCE HAS BEEN SOMEWHAT INCONSISTENT WITH COVERAGE
AND SEVERITY OF VISIBILITY RESTRICTIONS. THE MOST FAVORABLE AREAS
FOR LOCALLY DENSE FOG FORMATION WILL LIKELY BE WHERE PRECIPITATION
FALLS LATER THIS EVENING.
AN AREA OF SURFACE HIGH PRESSURE BEGINS TO DROP OUT OF ALBERTA AND
INTO THE NORTHERN PLAINS ON THURSDAY. THIS WILL PUSH TEMPERATURES
DOWN A FEW DEGREES WITH HIGHS RANGING FROM THE LOW 70S TO LOW 80S
ACROSS THE CWA. MODELS ADVERTISE LIGHT QPF LATE IN THE AFTERNOON AS
A MID-LEVEL JET STREAK NOSES INTO THE CENTRAL PLAINS...BUT DID NOT
ADD ANY MENTION OF POPS TO THE SHORT TERM FORECAST JUST YET AS THE
BETTER CHANCES LOOK TO BE AFTER 00Z FRIDAY.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 302 PM CDT WED SEP 9 2015
THE NAM REMAINS IN AGREEMENT WITH CURRENT FORECAST WITH A
DISTURBANCE DROPPING SOUTHEAST FROM SWRN SD INTO WRN NEBR
OVERNIGHT. THE GFS IS FASTER WITH THIS DISTURBANCE AND REMAINS
MOSTLY DRY. THEREFORE KEPT POPS LIMITED TO 20 PERCENT WEST OF A
LINE FROM GORDON THROUGH BROKEN BOW.
KEPT VERY NEAR PREVIOUS HIGHS FRIDAY AS EASTERLY WINDS BECOME
SOUTHEAST BY AFTERNOON AND WEAK WAA WILL NOT KICK IN UNTIL
AFTERNOON. THERE COULD ALSO BE A FEW SHOWERS AND CLOUDINESS
LINGERING AS WELL.
ON SATURDAY...A RETURN SOUTHERLY WIND RETURNS WITH HIGHS WARMING
TO NEAR 80 ACROSS THE WEST WHILE THE EAST REMAINS IN THE LOWER TO
MID 70S.
FOR SUNDAY THROUGH TUESDAY...ABOVE NORMAL TEMPERATURES. ZONAL FLOW
ALOFT ACROSS THE CENTRAL PLAINS SUNDAY WILL PERSIST INTO MONDAY AS
AN UPPER TROUGH DIGS INTO THE PACIFIC NORTHWEST. THIS WILL KEEP A
THERMAL RIDGE ACROSS THE REGION WITH HIGHS RANGING IN THE 80S. ON
TUESDAY...THE UPPER TROUGH WILL ADVANCE ACROSS MONTANA THROUGH
COLORADO WITH STRONG HEATING TO OCCUR IN ADVANCE ACROSS THE
CENTRAL PLAINS. FORECAST HIGH ARE 85 TO 90...ALTHOUGH THE
POTENTIAL IS THERE FOR HIGHS TO EXCEED 90 IN SOME AREAS OF WRN
NEBR. A COLD FRONT TUESDAY NIGHT TO COOL BACK HIGHS TO NEAR 75
NORTH AND NEAR 80 SOUTH. THE 12Z ECMWF HOWEVER IS MUCH WEAKER WITH
THE POST FRONTAL COOLDOWN AND SUGGESTS 80S STILL POSSIBLE. MAINLY
DRY THROUGH THE EXTENDED PERIODS...EXCEPT A SLIGHT CHANCE ERN
PNHDL TUESDAY AFTN...AND MOST AREAS TUESDAY NIGHT. LOOKS DRY
BEHIND THE FRONT FOR WEDNESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1140 PM CDT WED SEP 9 2015
FOR THE KLBF TERMINAL...SKIES WILL BE MAINLY CLEAR OVERNIGHT WITH
A SMALL THREAT FOR FOG TOWARD SUNRISE THURSDAY. VISBYS MAY DROP AS
LOW AS 5SM FROM 10Z TO 14Z. HIGH CLOUDS WILL INCREASE BY MID
MORNING...WITH BROKEN CIGS OF 20000 FT AGL EXPECTED AFTER 19Z
THURSDAY. FOR THE KVTN TERMINAL...EXPECT SCATTERED TO BROKEN CIGS
AROUND 20000 FT AGL OVER THE NEXT 24 HRS...WITH SOME BROKEN CIGS
AROUND 10000 FT AGL EXPECTED AFTER 17Z THURSDAY.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MARTIN
SHORT TERM...MARTIN
LONG TERM...ROBERG
AVIATION...CLB
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
940 AM PDT THU SEP 10 2015
.SYNOPSIS...MONSOON MOISTURE WILL KEEP THUNDERSTORMS IN THE FORECAST
ACROSS THE MOJAVE DESERT SOUTH OF LAS VEGAS AGAIN TODAY. MAINLY
DRY AND HOT CONDITIONS ARE EXPECTED FRIDAY AS HIGH PRESSURE
STRENGTHENS OVERHEAD. CONFIDENCE CONTINUES TO INCREASE IN MOISTURE
ASSOCIATED WITH TROPICAL STORM LINDA TO PUSH NORTH ACROSS THE
REGION THIS WEEKEND INTO EARLY NEXT WEEK.
&&
.UPDATE...SATELLITE LOOP SHOWED A LARGE AREA OF FAIRLY THICK CLOUD
COVER ACROSS MOST OF SAN BERNARDINO COUNTY INTO SOUTHERN MOHAVE
COUNTY. I UPDATED TO INCREASE SKY COVER ACCORDINGLY. I ALSO ADDED A
MENTION OF THUNDERSTORMS TO PORTIONS OF NORTHERN MOHAVE COUNTY AS
MODELS AND CURRENT MESOANALYSIS INDICATE SOME INSTABILITY AND THERE
SHOULD BE ENOUGH MOISTURE IN PLACE. -HARRISON-
&&
.PREV DISCUSSION...
346 AM PDT THU SEP 10 2015
.SHORT TERM...TODAY THROUGH SATURDAY MORNING.
CONVECTION FROM YESTERDAY AFTERNOON AND EVENING HAS DIMINISHED
ACROSS THE ENTIRE REGION. THE LATEST SATELLITE IMAGERY SHOWS MID-
LEVEL MOISTURE COURTESY OF TROPICAL STORM LINDA CONTINUING TO STREAM
FROM SOUTHWEST TO NORTHEAST ACROSS FAR SOUTHERN PORTIONS OF THE
FORECAST AREA. THIS WILL SET THE STAGE FOR ANOTHER DAY OF ISOLATED
TO SCATTERED THUNDERSTORMS ACROSS MAINLY MOHAVE AND SAN BERNARDINO
COUNTIES.
THE CLOUD SHIELD FROM LINDA WILL CONTINUE TO EASE NORTHWARD OVER THE
COURSE OF TODAY...WITH THE NORTHERN PERIPHERY OF THE CLOUD SHIELD
BEING A FAVORED REGION ALONG WITH TERRAIN FOR CONVECTIVE DEVELOPMENT
LATER THIS MORNING. THIS COINCIDES WITH THE FORECAST REGION OF BEST
INSTABILITY INDICATED ON THE LATEST RUNS OF THE NAM 12...WHICH WAS
THE BEST PERFORMING MODEL WITH INSTABILITY PARAMETERS YESTERDAY. THE
LATEST LOCAL HI-RES MODELS AND RUNS OF THE HRRR POINT TOWARD
CONVECTIVE INITIATION OCCURRING BETWEEN 18-19Z LATER TODAY ACROSS
CENTRAL AND SOUTHERN PORTIONS OF SAN BERNARDINO AND MOHAVE COUNTIES.
AT THIS TIME...IT APPEARS AS IF COVERAGE WILL BE SIMILAR TO WHAT WAS
OBSERVED YESTERDAY...WITH ACTIVITY AGAIN TAPERING OFF THIS EVENING
WITH THE LOSS OF DAYTIME HEATING. DRY MID-LEVEL AIR WILL AGAIN HELP
TO KEEP AREAS FROM ROUGHLY LAS VEGAS NORTHWARD EFFECTIVELY CAPPED
AGAIN TODAY.
THURSDAY NIGHT INTO FRIDAY...MID TO UPPER LEVEL DRY AIR WILL INTRUDE
THE AREA FROM THE NORTHEAST AS THE CENTER OF THE HIGH SHIFTS
WESTWARD. THIS WILL SCOUR OUT MOISTURE FROM NORTHEAST TO SOUTHWEST
AT MID AND UPPER LEVELS...CONFINING ANY CHANCES FOR THUNDERSTORMS TO
SOUTHWESTERN PORTIONS OF SAN BERNARDINO COUNTY. AFTERNOON HIGH
TEMPERATURES WILL CONTINUE TO RUN ROUGHLY 8-10 DEGREES ABOVE
SEASONAL NORMALS THROUGH SATURDAY AFTERNOON...BEFORE A PATTERN
CHANGE SPELLS A SHARP COOLDOWN AND AN INCREASE IN SHOWER AND
THUNDERSTORM ACTIVITY FROM SUNDAY ONWARD.
.LONG TERM...SUNDAY THROUGH WEDNESDAY.
CONFIDENCE IS INCREASING THAT ABUNDANT REMNANT MOISTURE FROM
DECAYING TROPICAL STORM LINDA WILL SPREAD OVER THE REGION SUNDAY AND
MONDAY. THE OPERATIONAL GFS AND ECMWF ARE NOW IN GENERALLY GOOD
AGREEMENT WITH THE EVOLVING PATTERN. THEY DEPICT THE REMNANT MID
LEVEL MOISTURE FROM LINDA BEING PULLED UP ALONG THE CALIFORNIA COAST
BY A CIRCULATION OVER THE EASTERN PACIFIC...CURRENTLY CENTERED NEAR
30N 135W. AS THIS CIRCULATION APPROACHES THE CENTRAL CALIFORNIA
COAST...IT APPEARS TO INFUSE THE WEAKENING MID LEVEL CIRCULATION
FROM LINDA AND KICK IT INLAND ACROSS SOUTHERN CALIFORNIA AND
SOUTHERN NEVADA SUNDAY. CONSIDERABLE CLOUD COVER AND LIGHT SHOWERS
WILL MOST LIKELY RESULT SUNDAY AS MODEL FORECAST SOUNDINGS INDICATE
ONLY MARGINAL INSTABILITY. SO...HEAVY RAIN PRODUCING THUNDERSTORMS
DO NOT APPEAR AS FAVORABLE AS THEY DO MONDAY...WHEN DEEPER MOISTURE
WILL BE IN PLACE. AN INCREASING SOUTHWEST JET IS FORECAST TO MOVE
OVER SOUTHERN CALIFORNIA AND SOUTHERN NEVADA MONDAY WHILE THE
CIRCULATION THAT MOVED INTO CENTRAL CALIFORNIA PHASES WITH A DEEP
LOW PRESSURE SYSTEM DROPPING INTO THE PACIFIC NORTHWEST. EASTERN SAN
BERNARDINO...CLARK...LINCOLN AND MOHAVE COUNTIES COULD SEE HEAVY
RAIN PRODUCING THUNDERSTORMS WITH SOME MORE ORGANIZED CELLS DUE TO
INCREASING WIND SHEAR. STORM MOTION WILL ALSO INCREASE WHICH WILL BE
A FACTOR WORKING AGAINST THE FLASH FLOOD THREAT. POP VALUES WERE
INCREASED 10-20 PERCENT SUNDAY THROUGH MONDAY DUE TO THE
A BROAD TROUGH IS FORECAST TO BE OVER THE WESTERN STATES TUESDAY AND
SOME DRYING SHOULD OCCUR DUE TO THE SOUTHWEST FLOW.
HOWEVER...LINCOLN AND MOHAVE COUNTIES MAY STILL SEE THE POTENTIAL
FOR SIGNIFICANT THUNDERSTORMS DUE TO LINGERING MOISTURE. WEDNESDAY
SHOULD SEE FURTHER DRYING FROM THE TROUGH WITH DECREASING STORM
COVERAGE. A DEFINITE COOLING TREND WILL OCCUR DUE TO THE
AFOREMENTIONED FACTORS WHICH WAS ALREADY INDICATED IN THE INHERITED
GRIDS. TEMPERATURES WERE DECREASED SLIGHTLY EACH DAY BASED ON THE
LATEST GUIDANCE.
&&
.AVIATION...FOR MCCARRAN...LIGHT WINDS GENERALLY UNDER 8 KTS ARE
EXPECTED TODAY...GENERALLY FROM AN EASTERLY DIRECTION DURING THE DAY
AND SOUTH-SOUTHWEST OVERNIGHT. SHRA/TSRA ARE POSSIBLE MAINLY TO THE
SOUTH OF THE TERMINAL TODAY...WITH A SLIGHT CHANCE OF TSRA
DEVELOPING IN THE MCCULLOUGH RANGE AND/OR SPRING MOUNTAINS LATER
THIS AFTERNOON.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...SCATTERED-ISOLATED SHRA/TSRA WILL BE POSSIBLE AGAIN
THIS AFTERNOON PRIMARILY SOUTH OF KLAS. GUSTY AND ERRATIC WINDS WILL
BE POSSIBLE IN AND NEAR ANY SHRA/TSRA. OTHERWISE RELATIVELY LIGHT
WINDS WILL FAVOR TYPICAL DIURNAL TRENDS. EXPECT SCT-BKN CLOUDS AOA
7K-12K FEET AS WELL SOUTH OF LAS VEGAS. AREAS OF FU AND HZ ARE
POSSIBLE IN AROUND KBIH REDUCING VSBY AND CREATING LOCALIZED
MOUNTAIN OBSCURATIONS.
&&
.SPOTTER INFORMATION STATEMENT...SPOTTERS ARE ENCOURAGED TO REPORT
ANY SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING
PROCEDURES.
&&
$$
SHORT TERM/AVIATION...PULLIN
LONG TERM.............ADAIR
FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:
HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
346 AM PDT THU SEP 10 2015
.SYNOPSIS...MONSOON MOISTURE WILL KEEP THUNDERSTORMS IN THE FORECAST
ACROSS THE MOJAVE DESERT SOUTH OF LAS VEGAS AGAIN TODAY. MAINLY
DRY AND HOT CONDITIONS ARE EXPECTED FRIDAY AS HIGH PRESSURE
STRENGTHENS OVERHEAD. CONFIDENCE CONTINUES TO INCREASE IN MOISTURE
ASSOCIATED WITH TROPICAL STORM LINDA TO PUSH NORTH ACROSS THE
REGION THIS WEEKEND INTO EARLY NEXT WEEK.
&&
.SHORT TERM...TODAY THROUGH SATURDAY MORNING.
CONVECTION FROM YESTERDAY AFTERNOON AND EVENING HAS DIMINISHED
ACROSS THE ENTIRE REGION. THE LATEST SATELLITE IMAGERY SHOWS MID-
LEVEL MOISTURE COURTESY OF TROPICAL STORM LINDA CONTINUING TO STREAM
FROM SOUTHWEST TO NORTHEAST ACROSS FAR SOUTHERN PORTIONS OF THE
FORECAST AREA. THIS WILL SET THE STAGE FOR ANOTHER DAY OF ISOLATED
TO SCATTERED THUNDERSTORMS ACROSS MAINLY MOHAVE AND SAN BERNARDINO
COUNTIES.
THE CLOUD SHIELD FROM LINDA WILL CONTINUE TO EASE NORTHWARD OVER THE
COURSE OF TODAY...WITH THE NORTHERN PERIPHERY OF THE CLOUD SHIELD
BEING A FAVORED REGION ALONG WITH TERRAIN FOR CONVECTIVE DEVELOPMENT
LATER THIS MORNING. THIS COINCIDES WITH THE FORECAST REGION OF BEST
INSTABILITY INDICATED ON THE LATEST RUNS OF THE NAM 12...WHICH WAS
THE BEST PERFORMING MODEL WITH INSTABILITY PARAMETERS YESTERDAY. THE
LATEST LOCAL HI-RES MODELS AND RUNS OF THE HRRR POINT TOWARD
CONVECTIVE INITIATION OCCURRING BETWEEN 18-19Z LATER TODAY ACROSS
CENTRAL AND SOUTHERN PORTIONS OF SAN BERNARDINO AND MOHAVE COUNTIES.
AT THIS TIME...IT APPEARS AS IF COVERAGE WILL BE SIMILAR TO WHAT WAS
OBSERVED YESTERDAY...WITH ACTIVITY AGAIN TAPERING OFF THIS EVENING
WITH THE LOSS OF DAYTIME HEATING. DRY MID-LEVEL AIR WILL AGAIN HELP
TO KEEP AREAS FROM ROUGHLY LAS VEGAS NORTHWARD EFFECTIVELY CAPPED
AGAIN TODAY.
THURSDAY NIGHT INTO FRIDAY...MID TO UPPER LEVEL DRY AIR WILL INTRUDE
THE AREA FROM THE NORTHEAST AS THE CENTER OF THE HIGH SHIFTS
WESTWARD. THIS WILL SCOUR OUT MOISTURE FROM NORTHEAST TO SOUTHWEST
AT MID AND UPPER LEVELS...CONFINING ANY CHANCES FOR THUNDERSTORMS TO
SOUTHWESTERN PORTIONS OF SAN BERNARDINO COUNTY. AFTERNOON HIGH
TEMPERATURES WILL CONTINUE TO RUN ROUGHLY 8-10 DEGREES ABOVE
SEASONAL NORMALS THROUGH SATURDAY AFTERNOON...BEFORE A PATTERN
CHANGE SPELLS A SHARP COOLDOWN AND AN INCREASE IN SHOWER AND
THUNDERSTORM ACTIVITY FROM SUNDAY ONWARD.
.LONG TERM...SUNDAY THROUGH WEDNESDAY.
CONFIDENCE IS INCREASING THAT ABUNDANT REMNANT MOISTURE FROM
DECAYING TROPICAL STORM LINDA WILL SPREAD OVER THE REGION SUNDAY AND
MONDAY. THE OPERATIONAL GFS AND ECMWF ARE NOW IN GENERALLY GOOD
AGREEMENT WITH THE EVOLVING PATTERN. THEY DEPICT THE REMNANT MID
LEVEL MOISTURE FROM LINDA BEING PULLED UP ALONG THE CALIFORNIA COAST
BY A CIRCULATION OVER THE EASTERN PACIFIC...CURRENTLY CENTERED NEAR
30N 135W. AS THIS CIRCULATION APPROACHES THE CENTRAL CALIFORNIA
COAST...IT APPEARS TO INFUSE THE WEAKENING MID LEVEL CIRCULATION
FROM LINDA AND KICK IT INLAND ACROSS SOUTHERN CALIFORNIA AND
SOUTHERN NEVADA SUNDAY. CONSIDERABLE CLOUD COVER AND LIGHT SHOWERS
WILL MOST LIKELY RESULT SUNDAY AS MODEL FORECAST SOUNDINGS INDICATE
ONLY MARGINAL INSTABILITY. SO...HEAVY RAIN PRODUCING THUNDERSTORMS
DO NOT APPEAR AS FAVORABLE AS THEY DO MONDAY...WHEN DEEPER MOISTURE
WILL BE IN PLACE. AN INCREASING SOUTHWEST JET IS FORECAST TO MOVE
OVER SOUTHERN CALIFORNIA AND SOUTHERN NEVADA MONDAY WHILE THE
CIRCULATION THAT MOVED INTO CENTRAL CALIFORNIA PHASES WITH A DEEP
LOW PRESSURE SYSTEM DROPPING INTO THE PACIFIC NORTHWEST. EASTERN SAN
BERNARDINO...CLARK...LINCOLN AND MOHAVE COUNTIES COULD SEE HEAVY
RAIN PRODUCING THUNDERSTORMS WITH SOME MORE ORGANIZED CELLS DUE TO
INCREASING WIND SHEAR. STORM MOTION WILL ALSO INCREASE WHICH WILL BE
A FACTOR WORKING AGAINST THE FLASH FLOOD THREAT. POP VALUES WERE
INCREASED 10-20 PERCENT SUNDAY THROUGH MONDAY DUE TO THE
A BROAD TROUGH IS FORECAST TO BE OVER THE WESTERN STATES TUESDAY AND
SOME DRYING SHOULD OCCUR DUE TO THE SOUTHWEST FLOW.
HOWEVER...LINCOLN AND MOHAVE COUNTIES MAY STILL SEE THE POTENTIAL
FOR SIGNIFICANT THUNDERSTORMS DUE TO LINGERING MOISTURE. WEDNESDAY
SHOULD SEE FURTHER DRYING FROM THE TROUGH WITH DECREASING STORM
COVERAGE. A DEFINITE COOLING TREND WILL OCCUR DUE TO THE
AFOREMENTIONED FACTORS WHICH WAS ALREADY INDICATED IN THE INHERITED
GRIDS. TEMPERATURES WERE DECREASED SLIGHTLY EACH DAY BASED ON THE
LATEST GUIDANCE.
&&
.AVIATION...FOR MCCARRAN...LIGHT WINDS GENERALLY UNDER 8 KTS ARE
EXPECTED TODAY...GENERALLY FROM AN EASTERLY DIRECTION DURING THE DAY
AND SOUTH-SOUTHWEST OVERNIGHT. SHRA/TSRA ARE POSSIBLE MAINLY TO THE
SOUTH OF THE TERMINAL TODAY...WITH A SLIGHT CHANCE OF TSRA
DEVELOPING IN THE MCCULLOUGH RANGE AND/OR SPRING MOUNTAINS LATER
THIS AFTERNOON.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...SCATTERED-ISOLATED SHRA/TSRA WILL BE POSSIBLE AGAIN
THIS AFTERNOON PRIMARILY SOUTH OF KLAS. GUSTY AND ERRATIC WINDS WILL
BE POSSIBLE IN AND NEAR ANY SHRA/TSRA. OTHERWISE RELATIVELY LIGHT
WINDS WILL FAVOR TYPICAL DIURNAL TRENDS. EXPECT SCT-BKN CLOUDS AOA
7K-12K FEET AS WELL SOUTH OF LAS VEGAS. AREAS OF FU AND HZ ARE
POSSIBLE IN AROUND KBIH REDUCING VSBY AND CREATING LOCALIZED
MOUNTAIN OBSCURATIONS.
&&
.SPOTTER INFORMATION STATEMENT...SPOTTERS ARE ENCOURAGED TO REPORT
ANY SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING
PROCEDURES.
&&
$$
SHORT TERM/AVIATION...PULLIN
LONG TERM.............ADAIR
FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:
HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
546 PM MDT FRI SEP 11 2015
.AVIATION...
00Z TAF CYCLE
UPPER RIDGE CENTERED OVER GREAT BASIN WITH DRY NW FLOW ALF. MOIST
LOW LEVEL UPSLOPE FLOW INTO THE EAST SLOPES CENTRAL MT
CHAIN...OCCASIONAL MT OBSCURATIONS IN MVFR/IFR CIGS/VSBYS
DEVELOPING 03Z-07Z AND PERSISTING UNTIL AROUND 12/16Z FROM THE CENTRAL
MT CHAIN OVER THE ERN PLAINS. SOME MVFR CIGS MAY BLEED INTO THE
RGV AFT 06Z ON GAP WINDS...ESPECIALLY AT KSAF. CURRENT CONVECTION
SOUTH OF INTERSTATE 40 AND ALONG THE HIGHER TERRAIN NORTH CENTRAL
MTS SHOULD DIMINISH AFT 03Z...ALTHOUGH SHORT TERM MODELS INDICATE
LIGHT PRECIPITATION DEVELOPING PORTIONS NE/E CENTRAL NM
THEREAFTER.
&&
.PREV DISCUSSION...333 PM MDT FRI SEP 11 2015...
.SYNOPSIS...
A BACK DOOR COLD FRONT SLIDING INTO EASTERN NEW MEXICO TODAY WILL
CONTINUE TO CREATE GUSTY WINDS...PARTICULARLY BELOW CANYONS IN THE
RIO GRANDE VALLEY. AREAS ON THE EAST SIDE OF ALBUQUERQUE MAY GUST UP
TO 35 MPH THIS EVENING. ISOLATED THUNDERSTORMS WILL DEVELOP OVER THE
STATE THIS WEEKEND...ESPECIALLY THE SOUTHERN HIGH TERRAIN. A SLIGHT
UPTICK IN STORM COVERAGE IS EXPECTED FOR WESTERN NEW MEXICO MONDAY
AND TUESDAY. DRIER AND BREEZY CONDITIONS WILL RETURN TO THE STATE
NEXT WEEK BEFORE A POTENTIAL INCREASE IN MOISTURE BY NEXT FRIDAY.
&&
.DISCUSSION...
THE POST-FRONTAL INVERSION OVER EASTERN NM IS HOLDING STRONG AND
CAPPING CHANCES AT RELEASING WHAT LITTLE SURFACE INSTABILITY IS
PRESENT OVER THE AREA. THIS IS ALSO EVIDENCED BY SCATTERED WAVE
CLOUDS ALONG AND EAST OF THE CENTRAL MT CHAIN. FORCING ALONG THE
SURFACE FRONT AND STRONG HEATING OVER CHAVES COUNTY IS PROVIDING
INSTABILITY FOR AT LEAST ISOLD ACTIVITY. A FEW MEAGER SHOWERS ARE
ATTEMPTING TO FIRE UP OVER THE NORTHERN HIGH TERRAIN WITH LITTLE
SUCCESS.
THE LATEST HRRR/RUC AND LOCAL WRF AGREE WITH THE SPC SSEO THAT THE
VAST MAJORITY OF ACTIVITY WILL TAPER OFF AFTER SUNSET. THE 12Z GFS
WAS STILL VERY WET FOR THE HIGH PLAINS THIS EVENING BUT REMAINDER OF
DETERMINISTIC GUIDANCE IS ON THE DRY SIDE. THE 18Z NAM STILL SHOWS
LOW CLOUDS REDEVELOPING OVER THE EAST WITH PERHAPS SOME LIGHT RAIN
OVERNIGHT. OVERALL LOWERED POPS AND REMOVED MENTION OF THUNDER
AFTER MIDNIGHT. THE OTHER STORY HAS BEEN GAP WINDS IN THE RIO
GRANDE VALLEY...WHICH ARE STILL PROGGED TO INCREASE DURING THE
EVENING. THE 19Z HRRR HAS DELAYED THE PEAK WINDS FOR THE ABQ EAST
SIDE UNTIL BTWN 8PM AND 1AM...WHICH IS CONSISTENT WITH THE LATEST
MET/MAV/ECS MOS GUIDANCE.
THIS WEEKEND LOOKS GENERALLY TRANQUIL AT THIS TIME WITH ONLY ISOLD
STORMS RECYCLING UNDER THE H5 RIDGE CRESTING EASTWARD FROM THE GREAT
BASIN. THE BEST STORM CHANCES WILL FOCUS OVER THE HIGHER TERRAIN OF
CATRON COUNTY AS INCREASINGLY MOIST SOUTHWEST FLOW ARRIVES OVER THE
AREA. TEMPS WILL REBOUND SEVERAL DEGREES SATURDAY OVER THE EAST THEN
BECOME HOT AGAIN BY SUNDAY WITH BETTER KATABATIC FLOW.
MODELS ARE STILL STRUGGLING WITH MOISTURE DELIVERY MONDAY/TUESDAY AS
SEVERAL COMPLEX UPPER FEATURES SHEAR EASTWARD AHEAD OF A DEVELOPING
LARGE SCALE UPPER TROUGH ALONG THE WEST COAST. IT APPEARS THAT THE
WESTERN THIRD WILL STILL FAVOR ISOLATED STORMS...HOWEVER TRENDS ARE
EVEN DRIER. LEE TROUGHING INCREASING OVER THE EAST WILL ALLOW FOR
WINDS TO TREND UP WITH HOT TEMPS ONCE AGAIN.
EXTENDED TRENDS TOWARD A WETTER PATTERN ARE ADVERTISED NOW BY BOTH
THE GFS AND ECMWF BEYOND FRIDAY. THERE ARE SOME INTERESTING FEATURES
TO ANALYZE AS AN ELONGATED UPPER RIDGE DEVELOPS OVER NORTHERN MEXICO
WITH FAST WSW FLOW ALOFT OVER THE NORTHERN ROCKIES. THE 700-500MB
LEVEL MOISTURE PATTERN HAS INDICATIONS OF A TAP TO THE EASTERN
PACIFIC. THIS COULD BE AN INITIAL SIGN OF THE LONG ANTICIPATED
ACTIVE SUBTROPICAL JET MORE COMMON WITH EL NINO IN THE SW CONUS.
GUYER
&&
.FIRE WEATHER...
THE BACK DOOR COLD FRONT ARRIVED EARLIER THAN SCHEDULED TODAY
BRINGING STABLER AIR OVER THE FIRE WEATHER FORECAST AREA. THE FRONT
DID BRING SOME LOW LEVEL MOISTURE INTO THE AREA AND THIS WILL RECYCLE
ON SATURDAY AS AN UPPER HIGH OVER THE GREAT BASIN BEGINS TO MIGRATE
IN THIS DIRECTION. MAINLY ISOLATED SHOWERS AND THUNDERSTORMS ARE
EXPECTED SATURDAY...EXCEPT FOR SOME SCATTERED ACTIVITY OVER THE SW
MOUNTAINS. TEMPERATURES AND VENTILATION WILL GENERALLY TREND UPWARD
WHILE HUMIDITIES TREND DOWNWARD.
SUNDAY THE UPPER HIGH WILL WEAKEN INTO A RIDGE OF HIGHER PRESSURE
WITH AN AXIS ORIENTED NORTH TO SOUTH ALONG NEW MEXICOS RIO GRANDE
VALLEY. THIS WILL FUNNEL MOISTURE NORTHWARD OVER WESTERN PARTS OF
THE FORECAST AREA WHERE AN UPTICK IN HUMIDITIES AND THUNDERSTORM
COVERAGE IS EXPECTED WITH A SLIGHT DROP IN TEMPERATURES. ELSEWHERE
TEMPERATURES WILL CONTINUE TO WARM WHILE HUMIDITIES FALL. HIGH
HAINES INDICES IN THE 5 TO 6 RANGE ARE EXPECTED ALONG AND NORTH OF I-
40.
MONDAY THROUGH THE MIDDLE OF NEXT WEEK MOISTURE SHOULD CONTINUE TO
FUNNEL OVER WESTERN AREAS...AND TO A LESSER EXTENT CENTRAL
AREAS...AS A LONG WAVE TROUGH TAKES SHAPE OVER THE W COAST.
SHORTWAVE TROUGHS WILL EJECT NORTHEASTWARD FROM THIS FEATURE ACROSS
THE NORTHERN AND CENTRAL ROCKIES MONDAY AND TUESDAY...INTERACTING
WITH THIS MOISTURE AND STRENGTHENING THE FLOW ALOFT FOR AN UPTICK IN
SHOWER AND THUNDERSTORM ACTIVITY ON THESE DAYS. THE MONSOON PLUME
MAY WEAKEN SOME WEDNESDAY AND THURSDAY IF SOME DRIER AIR CAN GET
ENTRAINED IN THE WAKE OF MONDAY AND TUESDAYS SHORTWAVES AS DEPICTED
BY THE GFS AND ECMWF. ALSO ON MONDAY...A LEE TROUGH SHOULD TRIGGER
BREEZY TO WINDY CONDITIONS ACROSS THE NORTHEAST HIGHLANDS AND PLAINS.
44
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
1145 PM MDT WED SEP 9 2015
.AVIATION...
06Z TAF CYCLE
SHOWERS HAVE MOVED OUT OF THE AREA. EXPECT VFR CONDITIONS AT THE
TAF SITES OVERNIGHT. LOW CLOUDS AND FOG NOT LIKELY TO OCCUR
TONIGHT AT KLVS...KTCC AND KROW...DUE TO THE HIGH CLOUD COVER
AND WINDS BECOMING MORE SW. CROP OF SHOWERS AND STORMS THURSDAY
PM WILL BE LESS IN COVERAGE AND INTENSITY...FAVORING THE NE WHERE
A COLD FRONT WILL BE APPROACHING...AND THE SOUTHERN HIGH TERRAIN.
&&
.PREV DISCUSSION...310 PM MDT WED SEP 9 2015...
.SYNOPSIS...
SCATTERED THUNDERSTORMS OVER CENTRAL NEW MEXICO WILL TAPER OFF THIS
EVENING. THE COVERAGE OF STORMS WILL FOCUS OVER SOUTHWEST NEW MEXICO
ON THURSDAY. DRIER AIR SETTLING INTO NORTHERN NEW MEXICO TONIGHT AND
THURSDAY NIGHT WILL ALLOW LOW TEMPERATURES TO SETTLE INTO THE 30S
AND 40S. A BACK DOOR COLD FRONT WILL SHIFT DOWN THE EASTERN PLAINS
ON FRIDAY ALLOWING FOR ANOTHER UPTICK IN STORMS. HIGH TEMPERATURES
WILL FALL BELOW NORMAL WITH MANY AREAS STAYING IN THE 70S. ISOLATED
STORMS ARE EXPECTED OVER THE WEEKEND BEFORE THE NEXT INCREASE IN
COVERAGE DEVELOPS MONDAY AND TUESDAY.
&&
.DISCUSSION...
THE COMBINATION OF A 40-50KT 300MB JET CORE AND MOIST UNSTABLE
UPSLOPE FLOW ALONG THE EAST SLOPES OF THE CENTRAL MT CHAIN TODAY
HAS LED TO A FEW STRONG TO LOCALLY SEVERE STORMS. SPC SSEO PICKED
UP ON THE COVERAGE AREA VERY WELL. HRRR AND LOCAL WRF SHOW THIS
ACTIVITY TAPERING OFF DURING THE EVENING WHILE DRYING TAKES PLACE
FROM NORTH TO SOUTH. SFC DEWPOINTS FROM THE NAM12 SHOW UPPER 20S/
LOW 30S TONIGHT ACROSS THE NW HALF OF THE STATE...WHICH COMBINED
WITH RADIATIONAL COOLING WILL LEAD TO CHILLY TEMPS. ANGEL FIRE IS
EXPECTED TO HIT FREEZING FOR THE 1ST TIME SINCE AUGUST 5TH.
THE AXIS FOR MOIST INSTABILITY WILL SHIFT FARTHER SOUTH THURSDAY
INTO SW NM WHILE DRY AIR ALOFT CONTINUES PRESSING S/SE OVER NORTHERN
NM. A FEW STORMS ARE STILL LIKELY AS WEAKLY FAVORABLE UPPER LEVEL
JET DYNAMICS DRIFT SOUTH OUT OF COLORADO. AT THE SURFACE THE FIRST
SIGNS OF A BACK DOOR FRONT WILL FLIRT WITH THE FAR NE PLAINS THUS
PROVIDING YET ANOTHER FORCING MECHANISM WITHIN COLFAX AND UNION
COUNTIES. THIS FRONT WILL SURGE INTO EASTERN NM AND THRU GAPS IN
THE CENTRAL MT CHAIN FRIDAY. MEANWHILE A 590DM H5 HIGH CENTER
WILL BECOME POSITIONED OVERHEAD AND FOCUS MORE TERRAIN DOMINATED
STORM COVERAGE FRIDAY THROUGH THE WEEKEND.
EXTENDED MODEL GUIDANCE IS GOING TO HAVE A DIFFICULT TIME WITH
THE REMNANTS OF HURRICANE LINDA NEXT WEEK AS SEVERAL DISORGANIZED
UPPER LEVEL VORT FEATURES TAKE SHAPE ALONG THE WEST COAST. FOR NOW
IT APPEARS MONDAY/TUESDAY COULD FEATURE AN UPTICK IN STORM
COVERAGE AS A PORTION OF THE 700-500MB MOISTURE AXIS CROSSES NM.
GUYER
&&
.FIRE WEATHER...
A NEW CENTROID OF HIGH PRESSURE HAS TAKEN SHAPE OVER THE GREAT
BASIN. THIS WILL FUNNEL DRIER AIR OVER NM FROM THE NORTHWEST WITH
MINIMUM HUMIDITIES FALLING A FEW TO 14 DEGREES ACROSS THE FORECAST
AREA THURSDAY. SINCE LOW LEVEL FLOW WILL ALSO TAKE ON MORE OF A
SOUTHWESTERLY COMPONENT ON THURSDAY...THERE WILL BE A DOWNTICK IN
SHOWER AND THUNDERSTORM COVERAGE WITH MAINLY ISOLATED ACTIVITY
FAVORING LOCATIONS ALONG AND EAST OF THE CONTINENTAL DIVIDE.
A STRONGER BACK DOOR COLD FRONT FRIDAY WILL BRING WITH IT MORE
MOISTURE WITH AN UPTICK IN SHOWER AND THUNDERSTORM ACTIVITY ALONG
AND EAST OF THE CENTRAL MOUNTAIN CHAIN DURING THE AFTERNOON...THEN
AS FAR WEST AS THE CONTINENTAL DIVIDE DURING THE EVENING. THIS FRONT
IS FORECAST TO PRODUCE A MODERATELY GUSTY EAST CANYON WIND IN THE
MIDDLE AND LOWER RIO GRANDE VALLEY FRIDAY AND FRIDAY NIGHT. ANOTHER
CROP OF THUNDERSTORMS IS EXPECTED ALONG AND EAST OF THE CONTINENTAL
DIVIDE ON SATURDAY AS MOISTURE RECYCLES...BUT THERE WILL BE A
DOWNTICK IN COVERAGE.
THE UPPER HIGH IS FORECAST TO MIGRATE SOUTHEASTWARD TO AROUND THE NM
BOOT HEEL ON SUNDAY...THEN TO THE SE OF NM ON MONDAY AS AN UPPER
LEVEL TROUGH DEEPENS INTO A LOW PRESSURE SYSTEM ON THE WEST COAST
AND EJECTS SOME OF ITS SHORTWAVE ENERGY INLAND ACROSS THE CENTRAL
ROCKIES. THERE ARE SIGNIFICANT DISAGREEMENTS BETWEEN MODELS ON THE
TRACK AND TIMING OF THIS LOW AND THE SHORTWAVES...BUT THE GFS AND
ECMWF DO AGREE FAIRLY WELL ON A TAP OF SUBTROPICAL MOISTURE IN
STRENGTHENING SW FLOW ALOFT REACHING SW AREAS SUNDAY AND MUCH OF
CENTRAL AND WESTERN NM MONDAY.
A ROLLER COASTER OF TEMPERATURES IS EXPECTED THROUGH THE WEEKEND.
HIGH TEMPERATURES WILL WARM A FEW TO 5 DEGREES THURSDAY...THEN FALL
WITH THE BACK DOOR COLD FRONT FRIDAY. FALLING TEMPERATURES WILL
CONTINUE IN THE WEST THROUGH SATURDAY...WHILE EASTERN READINGS BEGIN
TO REBOUND. HIGH TEMPS SHOULD THEN WARM SUNDAY AS THE CENTER OF HIGH
PRESSURE DRAWS NEAR...THEN BEGIN TO FALL IN THE WEST AGAIN MONDAY AS
BETTER MOISTURE ARRIVES. MINIMUM HUMIDITIES SHOULD FALL A FEW TO 22
PERCENT ON SUNDAY BEFORE BEGINNING TO REBOUND IN THE WEST ON MONDAY.
HIGH HAINES VALUES IN THE 5 TO 6 RANGE ARE EXPECTED OVER NORTHWEST
AND NORTH CENTRAL AREAS THURSDAY...THEN OVER NW AND WEST CENTRAL
AREAS FRIDAY. EXTREME VALUES SHOULD ABATE EAST OF THE CONTINENTAL
DIVIDE WITH THE ARRIVAL OF BETTER MOISTURE ON FRIDAY NIGHT AND
SATURDAY...ONLY TO OVERSPREAD MOST LOCATIONS ALONG AND NORTH OF
INTERSTATE 40 ON SUNDAY. NORTHEAST AREAS MAY CONTINUE TO BE
AFFLICTED WITH HIGH HAINES ON MONDAY.
POCKETS OF POOR VENTILATION WILL IMPACT WEST CENTRAL AREAS
WEDNESDAY...THEN NORTH CENTRAL...CENTRAL AND SOUTHWEST AREAS
THURSDAY. POCKETS OF POOR VENTILATION MAY LINGER INTO FRIDAY WEST
OF THE CONTINENTAL DIVIDE AND OVER THE SANGRE DE CRISTOS...BUT
VENTILATION LOOKS TO IMPROVE MOST PLACES SATURDAY AND ESPECIALLY
SUNDAY. RATES SHOULD THEN STAY GOOD TO EXCELLENT MONDAY. 44
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
701 PM EDT THU SEP 10 2015
.SYNOPSIS...
HIGH PRESSURE REMAINS WELL OFF THE SOUTHEAST COAST THROUGH
FRIDAY. A WEAK TROF OF LOW PRESSURE WILL APPROACH FROM THE WEST
TONIGHT THEN SLOWLY MOVE INTO THE AREA ON FRIDAY. AREA OF LOW
PRESSURE WILL DEVELOP NORTHWEST OF THE REGION SATURDAY INTO
SATURDAY NIGHT THEN PASS NORTH OF THE AREA SUNDAY. A COLD FRONT
TRAILING THE LOW WILL CROSS THE AREA SUNDAY NIGHT FOLLOWED BY HIGH
PRESSURE EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
AS OF 650 PM THURSDAY...LINE OF CONVECTION ACROSS THE EASTERN
PIEDMONT MAY AFFECT OUR COASTAL PLAINS COUNTIES OVER THE NEXT
SEVERAL HOURS. LATEST 3KM HRRR SHOWS THIS WITH SOME OF THE
ACTIVITY MAKING CLOSE TO THE COAST BY MORNING. HAVE TWEAKED POPS
TO HIGH CHANCE INLAND TAPERING BACK TO SLIGHT CHANCE COAST. STORMS
HAVE HAD THE HISTORY OF PRODUCING HEAVY RAINFALL...FREQUENT
LIGHTNING AND A BIT OF WIND DAMAGE NEAR THE NORTH
CAROLINA/VIRGINIA BORDER. AIRMASS STILL QUITE UNSTABLE ACROSS OUR
REGION...BUT WOULD EXPECT TO STORMS TO WEAKEN SOME WITH LOSS OF
HEATING OVER THE NEXT 2-3 HOURS. ANOTHER WARM/MUGGY NIGHT WITH
LOWS RANGING FROM LOW 70S DEEP INLAND TO UPPER 70S BEACHES.
REMNANT CONVECTIVE CLOUD DEBRIS/INCREASING CLOUDINESS OVERNIGHT
SHUD DETER WIDESPREAD FOG FORMATION ALTHO SOME PATCHY FOG
ESPECIALLY WHERE ANY PRECIP HAS FALLEN WILL BE POSSIBLE.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/...
AS OF 320 PM THU...SFC TROF SLOWLY PUSHES INTO THE FORECAST AREA
FRIDAY AND MAY HELP FOCUS INCREASING PRECIP CHANCES DURING DIURNAL
CYCLE AIDED BY APPROACH OF WEAK MID LEVEL TROF DURING THE
AFTERNOON. WILL CAP POPS AT GOOD CHANCE FOR NOW GIVEN THE
GENERALLY WEAK FORCING MECHANISMS BUT PRECIP CHANCES MAY NEED TO
BE RAISED IF LATER MODELS RUNS SUPPORT A WETTER SCENARIO.
INSTABILITY WILL BE LACKING FRIDAY SO NOT EXPECTING MUCH OF SEVERE
THREAT. NOT AS WARM TOMORROW AS CLOUDS WILL HELP HOLD TEMPS IN THE
MID AND UPPER 80S BUT WITH DEW POINTS REMAINING IN THE 70S, HEAT
INDICES WILL REACH INTO THE LOW 90S.
&&
.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
AS OF 310 PM THU...UNSETTLED THIS WEEKEND AS STRONG FRONTAL
SYSTEM IMPACTS THE REGION...THEN DRIER AND COOLER FOR NEXT WEEK.
A STRONG COLD FRONT WILL APPROACH THE REGION FRI NIGHT AND SAT AS
ASSOCIATED UPPER LEVEL TROUGH DEEPENS TO THE WEST. SPC HAS ENC
OUTLOOKED IN MARGINAL RISK FOR SVR TSTMS SAT. DEEP SW FLOW
CONTINUES AHEAD OF THE FRONT WITH THE REGION IN THE WARM SECTOR.
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ARE EXPECTED WITH
GOOD FORCING AND INCREASING SHEAR. AT THIS TIME THINK THE BEST
CHANCE FOR STRONG/SEVERE STORMS WOULD BE LATE AFTERNOON AND EARLY
EVENING...WITH THE MAIN THREATS DAMAGING WIND GUSTS AND LOCALLY
HEAVY RAINFALL. LATEST 12Z GUIDANCE HAS SLOWED THE BOUNDARY AND
ASSOCIATED PRECIP SLIGHTLY. THE LIMITING FACTOR CONTINUES TO BE
INSTABILITY. THOUGH MORE INSTABILITY COULD BE REALIZED IF WE SEE
SOME BREAKS IN THE CLOUDS. ADJUSTED POPS SLIGHTLY...THOUGH
CONTINUED HIGH CHANCE INCREASING TO LIKELY SAT EVENING/NIGHT.
UPPER LOW AND TROUGH STRENGTHEN TO THE NORTH SUNDAY AS TRAILING
COLD FRONT PUSHES THROUGH THE AREA. GFS STILL SLIGHTLY FASTER THAN
THE ECMWF WITH THE FRONTAL PASSAGE...BUT EXPECT FRONT TO MOVE
THROUGH LATE SUN/SUN EVENING. DRIER AND COOLER AIR WILL BE
GRADUALLY FILTERING INTO THE REGION WITH PRECIP TAPERING OFF FROM
WEST TO EAST.
HIGH PRESSURE WILL BUILD OVER THE AREA MONDAY AS UPPER TROUGH
PUSHES OFF THE EAST COAST. HIGH WILL REMAIN ANCHORED OVER THE
AREA THROUGH THURSDAY. VERY PLEASANT WEATHER EXPECTED WITH THE
REGION SEEING THE FIRST GLIMPSE OF FALL...AS DEWPOINTS DROP INTO
THE 50S. LOW LEVEL THICKNESS VALUES SUPPORT TEMPS A FEW DEGREES
BELOW NORMAL...WITH HIGHS IN THE UPPER 70S/LOW 80S AND OVERNIGHT
LOWS IN THE MID/UPPER 50S INLAND AND LOW/UPPER 60S ALONG THE
COAST.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
SHORT TERM /THROUGH 00Z SATURDAY/...
AS OF 655 PM THURSDAY...SCATTERED THUNDERSTORMS MOVING OFF THE
EASTERN PIEDMONT MAY IMPACT THE KPGV/KISO TAF SITES THROUGH LATE
EVENING. LESSER CHANCES OF CONVECTION AT KEWN/KOAJ. THINK DEBRIS
CLOUDINESS FROM THIS CONVECTION ACCOMPANIED BY WEAK LOW-LEVEL
MIXING SHOULD PRECLUDE ANY WIDESPREAD FOG FORMATION
OVERNIGHT...ALTHOUGH A FEW PATCHES OF DENSE FOG WILL BE POSSIBLE
IN AREAS THAT RECEIVE RAINFALL. VFR CONDITIONS SHOULD PREVAIL
THROUGH MID-AFTERNOON FRIDAY AS WILL LIKELY BE DELAYED INTO THE
AFTERNOON.
LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AS OF 310 PM THU...PERIODS OF SUB-VFR WILL BE POSSIBLE FRI NIGHT
THROUGH SUNDAY...WITH SCATTERED TO NUMEROUS SHOWER/TSTMS AHEAD OF
A STRONG COLD FRONT. PRED VFR CONDITIONS SHOULD RETURN BY LATE
SUNDAY AS A COLD FRONT PUSHES THROUGH THE TERMINALS.
&&
.MARINE...
SHORT TERM /THROUGH FRIDAY/...
AS OF 7 PM THURSDAY...GRADIENT BETWEEN APPROACHING FRONTAL TROUGH AND
HIGH PRESSURE OFFSHORE WILL CONTINUE TO CREATE SW WINDS OF 10 TO
20 KNOTS WITH FREQUENT GUSTS TO AROUND 25 KNOTS OVER THE PAMLICO
SOUND AND CENTRAL AND SOUTHERN WATERS. SMALL CRAFT ADVISORIES WILL
REMAIN IN EFFECT INTO EARLY FRIDAY MORNING. THE TROF PUSHES INTO
THE MARINE AREA FRIDAY WITH WINDS SHIFTING NORTH AND BECOMING
LIGHT OVER NORTHERN COASTAL WATERS, WHILE REMAINING SW AT MODERATE
SPEEDS OVER SOUTHERN AREAS DURING THE AFTERNOON.
LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AS OF 310 PM THU...A STRONG COLD FRONT WILL APPROACH THE WATERS
FROM THE WEST FRIDAY NIGHT AND SATURDAY. PRESSURE GRADIENT WILL
TIGHTEN WITH SWLY WINDS INCREASING TO 15-25KT AND SEAS BUILDING TO
4-6FT. PERIOD OF SCA CONDITIONS EXPECTED TO DEVELOP EARLY SAT
EVENING AND CONTINUE INTO EARLY SUN MORNING...MAINLY SOUTH OF
OREGON INLET. SW/WSW 10-20KT CONTINUES SUN WITH SEAS 2-5FT. THE
FRONT WILL MOVE THROUGH THE WATERS LATE SUN/SUN EVENING...WITH
HIGH PRESSURE BUILDING IN BEHIND THE FRONT. HIGH PRESSURE WILL
REMAIN ANCHORED OVER THE AREA MONDAY AND TUESDAY. WINDS BECOMING
N/NW LESS THAN 15KT FOR MON AND SEAS 2-4FT...AND 10KT OR LESS TUE
WITH SEAS 1-3FT.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 AM EDT FRIDAY FOR AMZ135-152-154-
156-158.
&&
$$
SYNOPSIS...BTC
NEAR TERM...CTC
SHORT TERM...BTC
LONG TERM...CQD
AVIATION...BTC/CTC/CQD
MARINE...BTC/CTC/CQD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
150 AM EDT THU SEP 10 2015
.SYNOPSIS...A SURFACE TROUGH WILL REMAIN OVER CENTRAL NORTH CAROLINA
THROUGH TONIGHT. A COLD FRONT WILL APPROACH FROM THE NORTHWEST
THURSDAY AFTERNOON...BEFORE STALLING ACROSS THE AREA FRIDAY. A
STRONGER COLD FRONT AND UPPER LEVEL LOW WILL APPROACH FROM THE
NORTHWEST FRIDAY NIGHT AND SATURDAY.
&&
.NEAR TERM /THROUGH THURSDAY/...
AS OF 940 PM WEDNESDAY...
A WEAK PERTURBATION EVIDENT AT 700-500 MB IS NOW TRACKING ENE
THROUGH THE WRN CWA... BRINGING SCATTERED SHOWERS AND ISOLATED
BRIEFLY STRONG (BUT SUB-SEVERE) STORMS. THIS CONVECTION IS ALSO
BEING SUPPORTED BY WEAK LINGERING POST-SUNSET ELEVATED INSTABILITY.
DEEP MOIST FLOW PERSISTS WITH GULF AND ATLANTIC SOURCES...
CONTRIBUTING TO PW VALUES WELL ABOVE NORMAL... AROUND 2.0 INCHES.
THE LATEST HRRR AND HI-RES NMM CONTINUE TO TRACK THIS WAVE AND
ASSOCIATED CONVECTION NORTHEAST THROUGH THE CWA THROUGH ABOUT 08Z...
AND THE FORECAST UPDATE WILL REFLECT THIS TIMING AND PLACEMENT...
WITH CHANCE POPS (HIGHEST IN THE CENTRAL AND NE CWA... ALONG THE
SURFACE TROUGH) INTO THE EARLY OVERNIGHT HOURS BEFORE TAPERING
DOWNWARD AND DEPARTING. A SECOND WAVE NOW PUSHING THROUGH SE TN AND
INTO NW GA IS ALSO ON TRACK TO MOVE INTO THE WRN CWA LATE TONIGHT...
AND WHILE IT`S UNCLEAR IF THERE WILL BE ENOUGH ELEVATED INSTABILITY
TO SUSTAIN THIS ACTIVITY WITHIN A MARGINAL DEEP-LAYER SHEAR
ENVIRONMENT... WILL NEED TO LEAVE IN A MENTION OF AT LEAST ISOLATED
STORMS THROUGH THE NIGHT. OTHERWISE... EXPECT MOSTLY CLOUDY SKIES
WITH PLENTY OF CONVECTIVE DEBRIS CLOUDS AS WELL AS PATCHY STRATUS
LATE. LOWS OF 70-75. -GIH
ON THURSDAY...FOG/STRATUS WILL BURN OFF QUICKLY AFTER 10 AM AS
DAYTIME HEATING INCREASES...AND EXPECT LOW CLOUDS TO BECOME
SCATTERED BY LATE MORNING. HOWEVER...RAIN CHANCES WILL INCREASE
DURING EARLY AFTERNOON AS COLD FRONT APPROACHES FROM THE NORTHWEST.
BELIEVE THE MAIN CONCERN WILL BE LOCALLY HEAVY RAINFALL DUE TO DEEP
MOISTURE POOLING AHEAD OF THE FRONT...PUSHING PRECIPITABLE WATER
VALUES IN THE 1.8 TO 2 INCH RANGE FOR MUCH OF THE AREA.
OTHERWISE...LIGHT UPPER LEVEL WINDS AND ONLY MODEST INSTABILITY
SHOULD SUPPORT SCATTERED STORMS...MOST OF WHICH WILL REMAIN BELOW
SEVERE CRITERIA. AFTERNOON HIGH TEMPERATURES WILL RANGE FROM THE
MID/UPPER 80S NORTH TO THE LOW 90S SOUTH.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
AS OF 330 PM WEDNESDAY...
SOMEWHAT UNSETTLED PATTERN INTO FRIDAY WITH WEAK SURFACE BOUNDARY
OVER EASTERN NORTH CAROLINA WITH WEAK UPPER LEVEL WAVE TRACKING
FROM THE WEST THURSDAY NIGHT INTO FRIDAY MORNING. MODEL
DISCREPANCIES IN TIMING AND STRENGTH OF THIS WAVE EXIST. WHILE
THERE WILL BE SOME TENDENCY FOR DECREASE IN SHWR/TSTM ACTIVITY
THURS NIGHT INTO FRIDAY WITH SURFACE BOUNDARY SHIFTING EAST...IT
REMAINS IN THE AREA AND WASHES OUT TO SOME DEGREE LATE FRIDAY AS
DEEPER UPPER TROUGH DIGS TO THE WEST. UPPER WAVE MAY HELP KEEP
SOME ACTIVITY GOING OVERNIGHT AND 12Z NAM WITH SLOWER TIMING WANTS
TO DEVELOP QUITE A BIT OF PRECIP DURING THE DAY FRIDAY ACROSS
SOUTHERN HALF OF FCST AREA WITH CIRCULATION EVIDENT AT THE
SURFACE. THINK THIS IS OVERDONE AND LEANING TOWARD FASTER AND
DRIER SOLUTIONS FROM 12Z GFS AND ECMWF. BEST CHANCES FOR LINGERING
PRECIP THURS NIGHT AND SOME CONVECTIVE DEVELOPMENT LATER FRIDAY
WILL BE ACROSS SOUTHERN AND EASTERN AREAS...CLOSER TO DECAYING
SURFACE BOUNDARY...BUT NOT GOING HIGHER THAN LOW CHC POPS AT THIS
TIME.
SOME TYPICAL NOCTURNAL DECREASE IN SHOWER ACTIVITY AGAIN ON FRIDAY
NIGHT BUT A FEW MODELS...MOST NOTABLY CANADIAN STILL INDICATE AN
UPPER WAVE AHEAD OF DIGGING TROUGH AND KEEPING SOMETHING GOING...SO
WILL NOT ELIMINATE POPS FRI NIGHT EITHER. THEN BEST CHANCES FOR
MORE WIDESPREAD SHWR/TSTM ACTIVITY WILL BE SATURDAY WITH DIGGING
TROUGH MOVING INTO WESTERN APPALACHIANS AND APPROACHING LOW-LEVEL
BAROCLINIC ZONE WITH INCREASING SW FLOW. LOOKS LIKE THIS NEW FRONTAL
BOUNDARY WILL BE PUSHING THROUGH CENTRAL NC LATE IN THE DAY SATURDAY
AND TIMED FAIRLY WELL WITH MAX HEATING...AND GIVEN SOME UPPER LEVEL
SUPPORT AND AT LEAST MARGINAL SHEAR...STILL LOOKS LIKE A CHANCE FOR
SOME STRONG TO SEVERE STORMS FOR LATE SATURDAY. LIMITED INSTABILITY
WITH LOTS OF CLOUD COVER MAY KEEP A MORE WIDESPREAD SEVERE EVENT
FROM OCCURRING...BUT WORTH KEEPING A CLOSE EYE ON.
HAVE HIGH CHC TO LOW LIKELY POPS SATURDAY...AND NOT GOING HIGHER
ONLY BECAUSE TIMING COULD SHIFT SLOWER INTO THE EVENING SINCE
DIGGING TROUGHS ARE SOMETIMES NOT HANDLED WELL BY MODELS. TRENDS
THOUGH HAVE ACTUALLY BEEN TO SPEED THIS UP A BIT AND FOR NOW HAVE
POPS QUICKLY LOWERING FOR SATURDAY EVENING. THIS MAY ALL NEED TO BE
ADJUSTED.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 330 PM WEDNESDAY...
DEEP UPPER TROUGH STILL APPEARS TO BE PROGRESSIVE ENOUGH SUCH
THAT SURFACE FRONT LIKELY TO BE EAST OF RAH FCST AREA BY SUNDAY
MORNING...ALONG WITH DEEPER CONVECTION AND HIGHER CHANCES FOR
PRECIP. 12Z GFS ESPECIALLY FAST WITH THIS. HOWEVER AS THE UPPER
TROUGH LIFTS NORTHEAST...COOLER TEMPS ALOFT WILL RESULT IN MID
LEVEL LAPSE RATES THAT COULD SUPPORT VERY SHALLOW CONVECTIVE
SHOWERS... VERY UNLIKELY TO BE ANY THUNDER...MAINLY FOR THE
NORTHERN AND EASTERN PORTIONS OF THE AREA. IF MORE PROGRESSIVE
TRENDS CONTINUE MAY EVENTUALLY DROP PRECIP CHANCES ALTOGETHER FOR
SUNDAY. MAIN STORY SUNDAY WILL BE MUCH COOLER AIR MASS AND WITH AN
ABUNDANCE OF CLOUDS HIGH TEMPS SHOULD BE AT LEAST 5F BELOW NORMAL.
70S FOR MOST LOCATIONS.
FOR THE EARLY PART OF NEXT WEEK THE UPPER TROUGH LIFTS WELL
NORTHEAST OVER NEW ENGLAND AND IS REPLACED BY A SHALLOW UPPER RIDGE
WITH AN ASSOCIATED LARGE AREA OF SURFACE HIGH PRESSURE. THIS WILL
KEEP DEEPER MOISTURE WELL TO THE SOUTH OF THE AREA WITH LOWER
HUMIDITIES AND COOL OVERNIGHTS BUT SLOWLY RECOVERING MAX TEMPS BACK
INTO THE LOWER 80S BY MID WEEK.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
AS OF 147 AM THURSDAY...
24 HOUR TAF PERIOD: SHOWERS AND STORMS...ASSOCIATED WITH AN UPPER
LEVEL DISTURBANCE... ARE CONTINUING TO CROSS THE REGION WITH
ASSOCIATED SUB-VFR CONDITIONS MAINLY IMPACTING KFAY AND KRDU... AND
POTENTIALLY KRWI IN THE NEXT FEW HOURS. AFTER THAT... MORNING
STRATUS/FOG WILL LIKELY AFFECT MOST SITES AFTER 08Z... LIFTING IN
THE LATE MORNING HOURS. SHOWERS AND THUNDERSTORMS WITH POTENTIAL SUB-
VFR CONDITIONS WILL DEVELOP THURSDAY AFTERNOON AND EVENING AHEAD OF
AN APPROACHING COLD FRONT.
OUTLOOK: SHOWERS AND STORMS WILL BE POSSIBLE FRIDAY AND SATURDAY...
AHEAD OF A STRONG COLD FRONT THAT WILL CROSS THE REGION SATURDAY.
HIGH PRESSURE WILL MOVE IN TO THE AREA EARLY IN THE WEEK... BRINGING
A HIGH LIKELIHOOD OF VFR CONDITIONS.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD/RNK
SHORT TERM...RNK
LONG TERM...RNK
AVIATION...30
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1237 AM CDT THU SEP 10 2015
.UPDATE...
ISSUED AT 1237 AM CDT THU SEP 10 2015
CURRENT INHERITED FORECAST IS ON TRACK WITH ONLY A FEW MINOR
UPDATES NEEDED FOR THE EARLY MORNING FORECAST UPDATE.
UPPER LEVEL JET DYNAMICS AND SUBTLE EMBEDDED MID LEVEL IMPULSES
CONTRIBUTING TO BKN MID LEVEL CLOUDS ACROSS MONTANA AND MAINLY
CENTRAL AND SOUTHERN NORTH DAKOTA. A FEW WEAK RADAR RETURNS AS
WELL SO WILL MAINTAIN A SLIGHT CHANCE FOR A BRIEF/LIGHT SHOWER
ALONG THE PATH OF THE LEFT EXIT REGION OF A RATHER WEAK UPPER JET
STREAK PUSHING SOUTHEAST ACROSS THE REGION...WEST CENTRAL INTO MY
SOUTH CENTRAL AND SOUTHERN JAMES RIVER VALLEY AREAS.
TEMPERATURES NORTH CENTRAL SLOW TO DROP THOUGH WILL KEEP THE FROST
ADVISORY AS IS WITH A FEW MID 30S OVER SOUTHERN CANADA OBSERVED.
SKIES SHOULD CLEAR ACROSS MY FAR NORTH NEAR 12Z AS SURFACE HIGH
PRESSURE BUILDS SOUTH INTO THE NORTHERN PLAINS...SO STILL TIME FOR
TEMPS TO DROP.
UPDATE ISSUED AT 816 PM CDT WED SEP 9 2015
UPDATED THE POPS WITH THE HRRR MODEL WHICH SEEMED TO DEPICT SOME
OF THE RETURNS THE RADAR SHOWS. SO WENT WITH SLIGHT CHANCE OF
SHOWERS SOUTHWEST INTO THE SOUTH CENTRAL THIS EVENING.
UPDATE ISSUED AT 628 PM CDT WED SEP 9 2015
COLD FRONT WITH NO SIGNIFICANT WEATHER HAS MOVED THROUGH THE
STATE. SKIES WILL CLEAR ACROSS THE NORTH TONIGHT WHILE MORE CLOUDS
REMAIN ACROSS THE SOUTH. COOLEST TEMPERATURES OVERNIGHT ARE
FORECAST WHERE CLOUDS WILL BE CLEAR IN THE NORTH. THIS IS WHERE
THE FROST ADVISORY HAS BEEN ISSUED FOR TONIGHT. CURRENT FORECAST
TRENDING WELL WITH NO MAJOR CHANGES.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 305 PM CDT WED SEP 9 2015
FROST TONIGHT NORTH CENTRAL HIGHLIGHTS THE SHORT TERM FORECAST.
ISSUED A FROST ADVISORY FOR NORTH CENTRAL NORTH DAKOTA AND THE
TURTLE MOUNTAINS AREA FOR TONIGHT INTO THURSDAY MORNING AS COOL
SURFACE HIGH PRESSURE BUILDS IN. IT APPEARS THAT THESE
AFOREMENTIONED AREAS WILL REMAIN CLEAR THROUGH THE
NIGHT...REMAINING IN BETWEEN THE WRAP AROUND STRATUS FIELD IN
SOUTHERN CANADA AND THE MID LEVEL DECKS FORECAST TO REMAIN ACROSS
THE WEST AND SOUTH CENTRAL. THUS...DID UNDERCUT THE 12 UTC
GUIDANCE CONSENSUS FOR THESE AREAS WITH FORECAST LOWS IN THE MID
30S...IN LINE WITH WHAT OCCURRED ACROSS CANADA THIS MORNING IN A
SIMILAR SETUP. GIVEN CLOUD COVER...FORECAST LOWS IN THE 40S ARE
EXPECTED ELSEWHERE. HOWEVER...THIS WILL HAVE TO BE MONITORED. A
COOL THURSDAY IS FORECAST WITH HIGH PRESSURE REMAINING OVER THE
AREA WITH HIGHS IN THE 60S FOR ALL OF WESTERN AND CENTRAL NORTH
DAKOTA.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 305 PM CDT WED SEP 9 2015
QUIET AND COOL INTO THE BEGINNING OF NEXT WEEK...THEN CHANCES OF
SHOWERS AND THUNDERSTORMS RETURN TO THE FORECAST.
THURSDAY NIGHT A COOL SURFACE HIGH SETTLES OVER THE EASTERN DAKOTAS
WITH CLEAR TO PARTLY CLOUDY SKIES AND LIGHT WINDS. EXPECT
RADIATIONAL COOLING WITH DEWPOINTS IN THE 30S TO ALLOW TEMPERATURES
TO DIP INTO THE MID 30S. AS A RESULT...PATCHY FROST IS FORECAST OVER
PARTS OF WESTERN AND CENTRAL NORTH DAKOTA LATE THURSDAY NIGHT INTO
EARLY FRIDAY MORNING.
THE WEST COAST RIDGE AMPLIFIES THROUGH THE NORTHERN ROCKIES WITH
MEAN RIDGING THROUGH NORTH DAKOTA BY THE END OF THE DAY FRIDAY. THIS
SPELLS A WARMING TREND THROUGH THE WEEKEND AFTER A COOL MORNING ON
FRIDAY.
BY MONDAY NIGHT THE REGION COMES UNDER SOUTHWEST MID LEVEL FLOW AND
INCREASED MOISTURE AND INSTABILITY...AS A PACIFIC NORTHWEST LONG
WAVE TROUGH DEEPENS AND BY MID WEEK CUTS OFF OVER THE SOUTHERN
CANADIAN PRAIRIE PROVINCES. THE BASE OF THE TROUGH LIFTS NORTHEAST
INTO THE DAKOTAS TUESDAY NIGHT INTO WEDNESDAY. THUS HAVE CHANCES FOR
THUNDERSTORMS MONDAY NIGHT THROUGH TUESDAY NIGHT AHEAD OF THE
SYSTEM...AND RAIN SHOWERS WEDNESDAY BEHIND THE SYSTEM.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1237 AM CDT THU SEP 10 2015
SURFACE HIGH PRESSURE ACROSS SOUTHERN CANADA WILL MOVE SOUTH INTO
THE NORTHERN PLAINS TONIGHT AND THURSDAY. VFR EXPECTED THROUGH THE
06Z TAF PERIOD.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
FROST ADVISORY FROM 4 AM TO 9 AM CDT THIS MORNING FOR NDZ002>005-
011>013.
&&
$$
UPDATE...NH
SHORT TERM...AYD
LONG TERM...JV
AVIATION...NH
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
102 AM EDT THU SEP 10 2015
.SYNOPSIS...
A COLD FRONT OVER NORTHERN OHIO WILL CONTINUE TO MOVE SOUTHEAST
AWAY FROM THE LOCAL AREA TONIGHT. THE FRONT IS EXPECTED TO
EVENTUALLY STALL NEAR THE OHIO RIVER ON THURSDAY MORNING. WEAK
HIGH PRESSURE WILL BUILD OVER THE REGION TOMORROW AND TOMORROW
NIGHT. ANOTHER COLD FRONT WILL FOLLOW ON FRIDAY WITH A POTENT
UPPER AIR DISTURBANCE EXPECTED TO IMPACT THE LOCAL AREA OVER THE
WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
A FEW LIGHT SHOWERS OR SPRINKLES CONTINUE TO APPEAR ON ILN RADAR
SO WILL LEAVE A LOW 20-30 POP IN OUR SOUTHERN COUNTIES FOR A FEW
MORE HOURS. THE DRY LOW LEVEL AIR IS EVIDENT BY THE LOSS OF LOW
CLOUDS WITH MAINLY JUST MID AND HIGH LEVEL CLOUD OVER THE AREA.
ANY PRECIPITATION REACHING THE GROUND OVERNIGHT WILL BE VERY LIGHT
AS IT FALLS OUT OF THE HIGHER CLOUD DECK. SLIGHTLY REDUCED CLOUD
COVER LATE TONIGHT INTO TOMORROW. WITH LESS CLOUD COVER...LOWERED
MINS BY A DEGREE OR SO IN NE OHIO.
PREVIOUS DISCUSSION...
AS FEARED...LITTLE PRECIP HAS DEVELOPED THIS AFTERNOON. SOME
SCATTERED SHOWERS REMAIN OVER THE EASTERN END OF THE AREA. MOST OF
THE GUIDANCE INCLUDING THE LATEST RUC AND HRRR SHOW THE
POSSIBILITY OF NEW DEVELOPMENT THROUGH EARLY EVENING FROM ABOUT
I-71 EAST. THIS SEEM PLAUSIBLE GIVEN THE SHOWERS OVER INDIANA AND
SW OHIO SO WILL KEEP A SMALL MENTION FOR A FEW HOURS. BY MIDNIGHT
ALL BUT THE SE END OF THE AREA SHOULD BE DRY. THE SURFACE FRONT
WILL EVENTUALLY STALL AND THE THREAT FOR SHOWERS ACROSS THE SE TIP
OF THE AREA COULD PERSIST INTO THURSDAY MORNING. THE NEAREST
CLEARING IS STILL BACK BY CHICAGO SO THAT WILL TAKE SOME TO REACH
THE LOCAL AREA AS WELL. DO THINK THAT THAT ABOUT THE NW 1/3 TO
1/2 OF THE AREA WILL BECOME PARTLY CLOUDY BY MORNING. THIS WILL
RESULT IN A DECENT TEMPERATURE GRADIENT ACROSS THE AREA WITH LOW
60S IN THE SE AND READINGS WELL DOWN INTO THE 50S IN THE NW.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY NIGHT/...
JUST MINOR ADJUSTMENTS TO THE SHORT TERM TODAY AS THE PREVIOUS
PACKAGE WAS ON THE RIGHT TRACK. THURSDAY AND THURSDAY NIGHT WILL
BE DRY. ANOTHER COLD FRONT IS STILL ON TRACK FOR FRIDAY. VERY
LITTLE IF ANY PRECIP IS EXPECTED BEFORE 12Z. WILL END UP GOING
WITH A FEW HOURS OF LIKELY MOST AREAS. UNFORTUNATELY THE BEST
WINDOW FOR PRECIP IN THE EAST WILL BE FRIDAY AFTERNOON AND
EVENING. THERE WILL BE A DISTINCT AIRMASS CHANGE BEHIND THIS FRONT
WITH THE UNSEASONABLY COOL AIR SETTLING OVER THE AREA OVER THE
WEEKEND. AS A RESULT...INSTABILITY SHOWERS HELPED ALONG BY LAKE
ERIE CAN BE EXPECTED BOTH SATURDAY AND SUNDAY. BY 12Z SUNDAY 500
MB TEMPS WILL BE ON THEIR WAY TO NEG 20 OR COLDER WHICH WILL GIVE
LAKE TO 500MB TEMP DIFFERENCES OF 45 DEGREES OR GREATER. THIS
MEANS THUNDER WILL BE A GOOD BET DOWNWIND OF THE LAKE AND HAVE
BUMPED PRECIP CHANCES TO LIKELY IN FAR NE OH AND NW PA FOR
SATURDAY NIGHT. HAVE CONTINUED THE RECENT TREND OF LOWERING HIGH
TEMPS OVER THE WEEKEND. THERE COULD BE A FEW AREAS THAT FAIL TO
GET OUT OF THE 50S FOR HIGHS ON SUNDAY.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AN UPPER LEVEL LOW WILL BE MOVING OFF TO THE EAST ON SUNDAY WILL
BRING COLDER TEMPERATURES 10-15 DEGREES BELOW AVERAGE AND
NORTHWESTERLY FLOW TO NORTHERN OHIO AND NORTHEAST PA. THIS NORTHWEST
FLOW OFF OF LAKE ERIE...PLUS 850 MB TEMPERATURES OF 6-8C...AND WARM
LAKE WATER TEMPERATURES AROUND 70F (A TEMPERATURE DIFFERENCE OF
AROUND 25 DEGREES FAHRENHEIT) WILL ALLOW FOR SOME SIGNIFICANT
LAKE EFFECT RAIN TO DEVELOP OVER THE AREA ON SUNDAY INTO THE EARLY
PART OF MONDAY. IN SHORT...SUNDAY WILL BE MORE REPRESENTATIVE OF A
COLD AND RAINY NOVEMBER DAY THAN THE GLIMPSE OF JULY THAT WE HAD
OVER LABOR DAY WEEKEND.
LATE ON MONDAY...SOME UPPER LEVEL RIDGING WILL MOVE IN ALONG WITH A
SURFACE HIGH PRESSURE. WINDS WILL SHIFT TO COME FROM THE SOUTH AND
WILL WARM TEMPERATURES CLOSER TO CLIMO AND DRY THE AREA OUT FROM WET
WEATHER OVER THE WEEKEND. HIGH PRESSURE LOOKS TO BE IN PLACE THROUGH
A MAJORITY OF WEDNESDAY ALLOWING FOR A COUPLE OF DRY...TYPICAL MID-
SEPTEMBER DAYS IN NORTHERN OHIO AND NORTHWEST PA.
MODELS CURRENTLY DEPICT A COLD FRONT BEGINNING TO APPROACH THE AREA
BY THURSDAY MORNING...WHICH COULD BRING SOME WET WEATHER FOR THE END
OF NEXT WEEK. STILL A LITTLE FAR OUT TO TELL WHAT COULD HAPPEN WITH
THIS SYSTEM AS IT APPROACHES THE EASTERN GREAT LAKES.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/... A NARROW RIDGE OF HIGH
PRESSURE OVER LWR MI WILL MOVE SE INTO THE CWA THRU THE AFTERNOON
AND WEAKEN. DRIER AIR BEING PUSHED SOUTH WITH THE RIDGE SHOULD
SPREAD ACROSS THE AREA TO FLUSH OUT THE LOWER CLOUDS SO EXPECT ONLY
SCT CU WITH DAYTIME HEATING BY MIDDAY THU. MOISTURE POOLING AHEAD OF
THE NEXT COLD FRONT COULD START TO PRODUCE SOME CLOUDS FROM 6 TO 10K
FEET AFTER 00Z AT TOL.
OUTLOOK...NON VFR STARTING LATER FRIDAY AND CONTINUING THROUGH
THE WEEKEND...ESPECIALLY FOR NE OH AND NW PA.
&&
.MARINE...
HAVE CANCELED THE SMALL CRAFT ADVISORY. LATEST GUIDANCE
AND ANALYSIS OF CURRENT CONDITIONS LEADS TOWARD 2 TO OCCASIONALLY 4
FEET OVERNIGHT. THE GRADIENT IS NOT THAT TIGHT AND COLD AIR
ADVECTION NOT STRONG. NORTH FLOW COMES AROUND TO THE NORTHEAST THIS
EVENING AND WILL BE SITTING AT 10 TO 15 KNOTS SUSTAINED. HIGH
PRESSURE WILL STAY NORTH OF THE LAKE ON THURSDAY AND GET SQUEEZED
OUT BY AN APPROACHING COLD FRONT FROM THE NORTHWEST ON FRIDAY. THIS
FRONT WILL HAVE THE POTENTIAL TO CHURN UP THE LAKE WITH STRONG COLD
AIR ADVECTION COMMENCING FRIDAY NIGHT OR SATURDAY MORNING. SMALL
CRAFT ADVISORIES A POSSIBILITY THIS WEEKEND. UPPER LOW STAYS IN THE
VICINITY AND IT WILL BE A COOL AND SHOWERY WEEKEND. WINDS ARE NOT
TOO STRONG ALOFT AND WATERSPOUTS MAY BE POSSIBLE THIS WEEKEND TOO.
HIGH PRESSURE BUILDS ACROSS THE LOWER OHIO VALLEY MONDAY.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KUBINA
NEAR TERM...KUBINA/KEC
SHORT TERM...KUBINA
LONG TERM...SEFCOVIC
AVIATION...ADAMS
MARINE...OUDEMAN
AREA FORECAST DISCUSSION
NWS TULSA OK
355 PM CDT THU SEP 10 2015
.DISCUSSION...
A cold front will move south across the area late tonight and
Friday morning accompanied by scattered to numerous showers and
thunderstorms. The HRRR is much quicker moving convection into and
out of the area than most other models and have leaned towards
this solution. A limited severe risk will exist especially near
the Kansas and Missouri borders, and this is also the area where
the greatest storm coverage is expected.
Much cooler and drier air will move into the area for the weekend
bringing our first taste of fall. Southerly winds will return and
increase early next week resulting in a quick warmup. By the
latter half of next week, temperatures will be several degrees
above normal, and higher humidity levels will return as well. Rain
chances look like they will hold off until the very end of the
week when a frontal boundary will approach from the north.
Stayed close to guidance temperatures the next couple days.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 67 79 53 76 / 60 30 0 0
FSM 69 82 56 78 / 40 40 0 0
MLC 68 82 56 78 / 30 30 0 0
BVO 65 78 50 75 / 80 20 0 0
FYV 64 75 49 71 / 60 40 0 0
BYV 63 75 50 71 / 80 40 0 0
MKO 67 79 53 76 / 40 30 0 0
MIO 64 76 49 73 / 90 30 0 0
F10 68 79 55 77 / 40 30 0 0
HHW 68 88 59 81 / 20 20 0 0
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
SHORT TERM...18
LONG TERM....05
PLATE
AREA FORECAST DISCUSSION
NWS NORMAN OK
250 PM CDT THU SEP 10 2015
.DISCUSSION...
PRIMARY FORECAST CONCERN IS FOCUSED ON PRECIPITATION CHANCES TONIGHT
THROUGH FRIDAY IN RESPONSE TO A COLD FRONT MOVING ACROSS THE AREA.
CURRENTLY... 19Z SFC ANALYSIS PLACES THE COLD FRONT NEAR THE NE/KS
BORDER... WITH INCREASING CU DEVELOPMENT ALONG AND AHEAD OF THE
FRONT ACROSS NRN INTO CENTRAL KS. THIS FRONT WILL CONTINUE TO PUSH
SOUTHWARD THROUGH THE AFTN INTO THE EVENING... APPROACHING THE OK/KS
BORDER THROUGH THIS EVENING. CONTINUITY BETWEEN TRADITIONAL AND
MESOSCALE GUIDANCE REMAINS DECENT. THE HRRR AND HIRES WRFS CONTINUE
TO GENERATE CONVECTION WITH THE SFC TROUGH OVER THE PANHANDLES
THROUGH 00Z... THE 12Z NAM IS A STEP SLOWER... BUT SIMILAR. GIVEN
INCREASING DPTS THIS AFTN AND AN INCREASING ISENTROPIC RESPONSE INTO
THE EVENING ACROSS NWRN OK... FELT COMFORTABLE TO INCREASE PRECIP
CHCS IN THE NW BETWEEN 00-06Z. EXPECT PRECIP COVERAGE TO INCREASE
INCREMENTALLY OVERNIGHT WITH THE BEST CHANCES AFTER MIDNIGHT THROUGH
SUNRISE ACROSS NRN AND NERN OK. AS FOR SEVERE CHANCES... MODEST ML-
CAPE VALUES 1000-1700 J/KG ARE POSSIBLE THIS EVENING AND
OVERNIGHT... WITH 20 TO 30 KTS OF 0-6KM SHEAR. LOOKING AT BUFR
SOUNDINGS... MOST OF THIS INSTABILITY IS WELL ELEVATED... WITH ANY
STRONGER STORMS DEVELOPING A HAIL OR WIND THREAT... QUARTER TO HALF
DOLLAR SIZE HAIL AND 60 MPH WINDS. OVERALL... THE CHANCE FOR SEVERE
STORMS WILL RESIDE WITHIN A NARROW WINDOW OF TIME ACROSS NRN OK THIS
EVENING THROUGH SUNSET.
FRIDAY... SCATTERED SHOWERS AND THUNDERSTORMS WILL LIKELY BE ONGOING
AROUND SUNRISE ACROSS NERN INTO CENTRAL OK. CHANCES WILL CONTINUE
THROUGH THE AFTN ACROSS MUCH OF THE REGION AS THE COLD FRONT PUSHES
TOWARDS THE RED RIVER THROUGH THE AFTN. INTO THE LATE
AFTN/EVENING... SOME STEEPER LAPSE RATES MAY DEVELOP... RESULTING IN
SOME STRONGER THUNDERSTORMS NEAR THE RED RIVER. HOWEVER... SEVERE
CHANCES REMAIN LOW.
SHOULD BE A WONDERFUL WEEKEND AS TEMPS REMAIN MILD... WITH HIGHS IN
THE UPPER 70S AND LOWER 80S EACH DAY. TEMPS WILL START TO REBOUND
EARLY NEXT WEEK AS SRLY FLOW RETURNS AND TROUGHING DEVELOPS OVER THE
WRN US MON-TUE. OVERALL... THE FORECAST REMAINS DRY THROUGH MUCH OF
NEXT WEEK... WITH THE NEXT BEST CHANCE FOR PRECIP LATE NEXT WEEK AS
A FRONTAL BOUNDARY APPROACHES THE REGION.
JTK
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 67 79 56 77 / 20 20 10 0
HOBART OK 68 80 57 81 / 10 20 10 0
WICHITA FALLS TX 69 86 59 83 / 0 30 20 0
GAGE OK 62 78 52 80 / 30 20 10 0
PONCA CITY OK 65 78 50 77 / 60 30 0 0
DURANT OK 70 86 58 81 / 0 30 20 0
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
452 PM EDT THU SEP 10 2015
.SYNOPSIS...
A COLD FRONT AND UPPER TROUGH WILL SLOWLY SWEEP OVER THE SOUTHERN
APPALACHIAN REGION LATE THIS WEEK. BY EARLY NEXT WEEK...A COOL AND
DRY AIR MASS IS FORECAST TO SETTLE OVER THE WESTERN CAROLINAS AND
NORTHEAST GEORGIA. MOISTURE SHOULD BEGIN TO INCREASE OVER THE REGION
BY THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /THROUGH FRIDAY/...
415 PM UPDATE...WHILE THERE SO FAR HAS BEEN LITTLE CUMULUS
DEVELOPMENT IN THE I-85 CORRIDOR THIS AREA MAY BEGIN TO SEE
CONVECTIVE COVERAGE AS OUTFLOW BOUNDARIES FROM NC CONVECTION
DRIFT SWD. THE AREAS OF THE NC PIEDMONT AND LOWER SAVANNAH
RIVER VALLEY CURRENTLY SEEING SCT ACTIVITY SHOULD CONTINUE TO
SEE THIS BUBBLE UNTIL HEATING CEASES...BUT LITTLE EXPANSION IS
EXPECTED. SEVERAL RUNS OF THE HRRR HAVE SHOWN NEW DEVELOPMENT NEAR
SUNSET APPARENTLY AS WIND SHIFT LINE AND/OR OUTFLOW BOUNDARIES
FOCUS REMNANT BUOYANCY. STILL THINK ANY LINGERING ACTIVITY WILL
RAPIDLY DIMINISH IN THE 03-06Z TIMEFRAME.
AS OF 225 PM...THE AXIS OF AN UPPER TROF CONTINUES TO PUSH
EAST...ENTERING THE NC MTNS ATTM. MEANWHILE...A COLD FRONT WAS
ANALYZED WINDING FROM THE MID ATLANTIC TO THE TN VALLEY...TO THE
SOUTHERN PLAINS. THE AIR MASS ALONG AND SOUTH OF THE BNDRY IS QUITE
MOIST...WITH DEWPTS IN THE UPR 60S TO LWR 70S. THIS HAS RESULTED
IN SBCAPE IN THE 1000 TO 2000 J/KG RANGE...EVEN HIGHER JUST SOUTH
AND EAST OF THE CWFA. SO EXPECT CONVECTION TO CONTINUE TO INCREASE
IN COVERAGE AND INTENSITY ACRS THE AREA THRU THE AFTN.
CONVECTION SHUD DIMINISH THIS EVENING AS ATMOS STABILIZES AND UPPER
ENERGY EXITS TO THE EAST. THE COLD FRONT WILL STALL IN THE MTNS
FOR MUCH OF THE NIGHT...WHILE NWLY LLVL FLOW HELPS SCOUR OUT CLOUD
COVER. SO PATCHY FOG AND STRATUS IS EXPECTED TO DEVELOP ACRS THE
AREA...ESP WHERE THE HEAVIEST RAIN FALLS AND IN THE MTN VALLEYS.
TEMPS WILL DROP A CATEGORY OR TWO COOLER THAN THIS MORNING/S LOWS
FOR FRIDAY MORNING.
FRIDAY...THE CWFA WILL BE IN BETWEEN SHORTWAVE TROFS AND BETWEEN
SFC FRONTS. LLVL FLOW WILL REMAIN WLY TO NWLY...LIMITING MOISTURE
AND LLVL CONVERGENCE. SO EXPECT ONLY ISOLATED TO WIDELY SCATTERED
CONVECTION WITH PEAK HEATING FRIDAY AFTN. TEMPS WILL BE A CATEGORY
OR TWO ABOVE NORMAL.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
AS OF 215 PM THURSDAY...LINGERING SCATTERED/ISOLATED DIURNAL
CONVECTION IS EXPECTED TO WANE FRI EVENING...BUT POPS WILL INCREASE
AGAIN TOWARD DAYBREAK ACROSS THE MTNS...AS A BAND OF DEEP MOISTURE
ASSOCIATED WITH STRONG HEIGHT FALLS AND ASSOCIATED FRONTAL SURGE
APPROACHES THE FORECAST AREA. WHILE THE MOIST BAND IS EXPECTED TO
DIMINISH AS IT MOVES QUICKLY ACROSS THE FORECAST AREA DURING THE
MORNING...MID-LEVEL DRY SLOT WILL OVERSPREAD THE AREA DURING THE
AFTERNOON...WITH PART OF THE FRONT LIKELY GETTING HUNG UP A BIT
ACROSS THE MOUNTAINS...LIKELY NOT COMPLETELY CLEARING THE AREA UNTIL
A POTENT SHORT WAVE TROUGH MOVES ACROSS THE AREA DURING THE EVENING.
AS A RESULT...THERE SHOULD BE PLENTY OF LOW LEVEL MOISTURE AND
WARMTH LINGERING THROUGH THE DAY TO SUPPORT MODEST LEVELS OF
INSTABILITY. TERRAIN EFFECTS AND THE FRONT SHOULD PROVIDE FOCI FOR
SCATTERED CONVECTIVE DEVELOPMENT INTO THE AFTERNOON AND EARLY
EVENING...ESP FROM THE BLUE RIDGE EAST...PRIMARILY WARRANTING CHANCE
POPS.
WITH CANADIAN HIGH PRESSURE BUILDING INTO THE REGION IN THE WAKE OF
DEPARTING TROUGH/COLD FRONT...SUNDAY SHAPES UP TO BE A SPECTACULAR
EARLY TASTE OF AUTUMN...WITH MAXES EXPECTED IN THE 70S AND DEWPOINTS
LIKELY FALLING INTO THE 40S BY AFTERNOON.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 225 PM THURSDAY...THE EARLY PART OF THE MEDIUM RANGE WILL BE
DOMINATED BY AN ANOMALOUSLY DEEP...YET PROGRESSIVE EAST COAST LONG
WAVE TROUGH AND ASSOCIATED CANADIAN HIGH PRESSURE. THIS WILL SUPPORT
A CONTINUATION OF EARLY FALL-LIKE WEATHER...WITH TEMPS/DEWPOINTS
EXPECTED TO REMAIN BELOW CLIMO THROUGH AT LEAST TUESDAY. IN FACT...
MON MORNING IS EXPECTED TO BE DOWNRIGHT CHILLY ACROSS THE HIGH
ELEVATIONS...WITH TEMPS LIKELY DIPPING TO NEAR 40 ABOVE 4000 FEET OR
SO. HEIGHT RISES BY THE END OF THE PERIOD WILL RESULT IN TEMPS
CREEPING BACK TOWARD CLIMO...ALTHOUGH WITH SURFACE RIDGE AXIS
EXPECTED TO PERSIST ACROSS THE REGION...DEWPOINTS SHOULD BE SLOWER
TO RECOVER...AND IT APPEARS CHANCES FOR ANY DIURNAL CONVECTION...OR
PRECIP OF ANY STRIPE WILL BE BELOW 20 PERCENT THROUGH THE PERIOD.
&&
.AVIATION /21Z THURSDAY THROUGH TUESDAY/...
AT KCLT /21Z UPDATE/...A COLD FRONT WILL CROSS THE AREA TONIGHT FROM
THE NW. SCATTERED TO NUMEROUS SHRA AND TSRA WILL DEVELOP ALONG AND
AHEAD OF THE FRONT THIS AFTN. THERE WILL ALSO BE SOME LOW-END GUSTS
OUT OF THE SW...WHICH MAY BECOME VARIABLE /BUT MORE LIKELY W TO N/
IF ANY TSTMS ARE NEARBY. WILL CONTINUE TO HIGHLIGHT THIS IN A TEMPO
GROUP THRU 24Z. OVERNIGHT...EXPECT WINDS TO DIMINISH...WITH SOME
CLEARING OF SKIES. SO THERE MAY BE SOME PATCHY STRATUS AND/OR FOG
AROUND DAYBREAK. CONFIDENCE IS LIMITED BY THE POTENTIAL DOWNSLOPE
FLOW BEHIND THE FRONT...AND THE FACT THAT ANY PRECIP THIS AFTN WILL
IMPACT THE SEVERITY OF OVERNIGHT CLOUD/FOG DEVELOPMENT. WINDS WILL
SWITCH TO NW WITH THE FROPA AROUND 12Z...BUT SHUD REMAIN LIGHT.
ELSEWHERE...HAVE VCTS AND TEMPO GROUPS AT ALL SITES TO HIGHLIGHT
THREATS FROM ONGOING CONVECTION...THOUGH COVERAGE IS NOT EXPECTED
TO BECOME ANY BETTER THAN SCATTERED. WINDS WILL BE MARGINALLY
GUSTY ACRS THE UPSTATE OUT OF THE SW. WINDS WILL SHIFT OUT OF
THE NW AT KAVL BY EARLY EVENING...AND AT THE REST OF THE SITES
OVERNIGHT...AS A COLD FRONT PASSES THRU. WINDS WILL BE LIGHT AND
SKIES WILL SEE SOME GRADUAL CLEARING. SO PATCHY FOG AND/OR STRATUS
IS POSSIBLE...ESP WHERE RAIN FALLS AND IN THE MTN VALLEYS.
OUTLOOK...UNSETTLED CONDITIONS WILL CONTINUE THROUGH THE WEEKEND
AS A FRONT STALLS IN THE REGION...AND AN UPPER LEVEL LOW PRESSURE
SYSTEM DRIFTS EAST THROUGH THE APPALACHIANS. MTN VALLEY FOG AND
STRATUS ARE POSSIBLE EACH MORNING...WITH SCATTERED THUNDERSTORMS
MAINLY IN THE AFTN. DRIER CONDITIONS WILL ARRIVE EARLY NEXT WEEK.
CONFIDENCE TABLE...
21-03Z 03-09Z 09-15Z 15-18Z
KCLT HIGH 100% HIGH 100% MED 75% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 88% HIGH 94% HIGH 81% HIGH 97%
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
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...RWH
NEAR TERM...ARK/WIMBERLEY
SHORT TERM...JDL
LONG TERM...JDL
AVIATION...ARK/WIMBERLEY
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1153 PM CDT WED SEP 9 2015
.UPDATE...
UPDATED FOR THE 06Z AVIATION DISCUSSION
&&
.PREV DISCUSSION... /ISSUED 917 PM CDT WED SEP 9 2015/
DISCUSSION...
A WEAK 1012 MB SURFACE LOW IS SITUATED OVER WEST TN/NRN MS THIS
EVENING. BEST LIFT AND DEEPER MOISTURE IS PUSHING EAST INTO
MIDDLE TN. AREAL COVERAGE OF PRECIP IS RAPIDLY DIMINISHING WITH
JUST A FEW SHOWERS OVER PARTS OF WEST TN ATTM. CLEARING IS ALREADY
WORKING INTO PARTS OF NE AR. LATEST HRRR INDICATING THAT SHOWERS
AND THUNDERSTORMS MAY REDEVELOP ACROSS PARTS OF NORTH MS LATER
TONIGHT AS ANOTHER PIECE OF UPPER LEVEL ENERGY MOVES THROUGH. LEFT
LIKELY POPS WITH A MENTION OF THUNDER IN THAT AREA AFTER
MIDNIGHT. OTRW TENDED TO TRIM POPS AND ADDED A MENTION OF FOG
ESPECIALLY IN AREAS THAT WILL CLEAR OUT ACROSS NE AR.
SJM
PREV DISCUSSION... /ISSUED 237 PM CDT WED SEP 9 2015/
WIDESPREAD RAIN AND THUNDERSTORMS ARE ONGOING ACROSS MUCH OF THE
MIDSOUTH. FORTUNATELY THEY ARE SUB SEVERE...BUT WE HAVE ISSUED A
COUPLE OF FLASH FLOOD WARNINGS DUE TO LOCALLY HEAVY RAIN IN THE
MEMPHIS AND SURROUNDING METROPOLITAN AREAS. DOPPLER RADAR
ESTIMATES NEAR 4 INCHES OF RAIN HAS FALLEN IN THESE AREAS...WITH
ANOTHER ROUND OR TWO OF HEAVY RAIN POSSIBLE THIS AFTERNOON. ALL OF
THIS RAIN IS FALLING AS A COLD FRONT MOVES SLOWLY ACROSS THE
MIDSOUTH. ITS EXACT LOCATION IS MASKED BY RAIN COOLED AIR AND
OUTFLOW BOUNDARIES...BUT IT LOOKS TO HAVE SHIFTED SOUTH OF THE
INTERSTATE 40 CORRIDOR. TEMPERATURES RANGE FROM THE MIDDLE 80S IN
NORTHEAST MISSISSIPPI TO THE LOW 70S IN NORTHEAST ARKANSAS. THE
FRONT WILL CONTINUE TO SHIFT SLOWLY TO THE SOUTH TONIGHT...WITH
THUNDERSTORMS POSSIBLE MAINLY ALONG AND SOUTH OF THE FRONT...AND
LIGHTER RAIN SHOWERS TO THE NORTH.
TOMORROW WE MAY SEE BRIEF CLEARING...BUT A SECONDARY COLD FRONT IS
EXPECTED TO BRING MORE RAIN AND WEAK THUNDERSTORMS TO THE MIDSOUTH
TOMORROW EVENING...CONTINUING INTO FRIDAY. DEW POINTS AND
TEMPERATURES ARE NOT EXPECTED TO COOL SIGNIFICANTLY UNTIL AT LEAST
MIDDAY FRIDAY...SO UNTIL THEN THUNDERSTORMS WILL REMAIN A
POSSIBILITY. NONE ARE EXPECTED TO BE SEVERE. AS THE SECONDARY COLD
FRONT SHIFTS ACROSS THE MIDSOUTH FRIDAY...RAIN CHANCES WILL
DIMINISH QUICKLY AND WINDS WILL SHIFT FROM THE NORTH. PORTIONS OF
THE MIDSOUTH...ESPECIALLY EAST ARKANSAS AND WEST TENNESSEE MAY SEE
HIGH TEMPERATURES BEFORE NOON...WITH STEADY OR FALLING
TEMPERATURES DURING THE AFTERNOON.
OVER THE WEEKEND...EXPECT FALL LIKE CONDITIONS. AFTERNOON HIGHS
WILL BE IN THE LOW TO MIDDLE 70S ACROSS MOST OF THE MIDSOUTH UNDER
MOSTLY CLEAR SKIES. TEMPERATURES WILL TREND WARMER DURING THE
EARLY TO MIDDLE PART OF NEXT WEEK. HIGHS WILL BE BACK IN THE
MIDDLE TO UPPER 70S BY WEDNESDAY. NO SIGNIFICANT RAIN CHANCES ARE
EXPECTED TO RETURN TO THE MIDSOUTH UNTIL WEDNESDAY AT THE
EARLIEST.
30
&&
.AVIATION...
06Z TAF CYCLE
SCATTERED RAIN SHOWERS REMAIN OVER FAR EASTERN SECTIONS OF THE
FORECAST AREA LATE THIS EVENING AND THIS WILL CONTINUE TO MOVE
EAST AND OUT OF THE FORECAST AREA OVERNIGHT. CURRENT VFR
CONDITIONS OVER WESTERN SECTIONS OF THE FORECAST AREA SHOULD END
OVERNIGHT AS LOW CLOUDS RETURN. SOME FOG IS EXPECTED TO DEVELOP
OVERNIGHT OVER MOST OF THE FORECAST AREA. SOME SCATTERED SHOWERS
MAY DEVELOP ACROSS THE REGION THURSDAY MORNING BUT END BY THE
AFTERNOON AS VFR CONDITIONS RETURN. WINDS WILL BE MAINLY FROM THE
NORTHWEST AT 4 TO 8 KNOTS FOR MOST OF THE FORECAST PERIOD.
ARS
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
945 PM CDT FRI SEP 11 2015
.UPDATE...
02Z SURFACE ANALYSIS HAS THE COLD FRONT STILL POSITIONED JUST NORTH
OF THE CWA...LOCATED ROUGHLY ALONG A KILLEEN TO PALESTINE TO
NACOGDOCHES LINE. WITH THE SOUTHERN EXPANSION OF THE PLAINS 1020
MB HIGH...THIS BOUNDARY WILL TRAVEL ACROSS THE FORECAST AREA FROM
AROUND MIDNIGHT...PASSING OFF THE COAST AROUND SUNRISE. THERE IS
STILL A SLIGHT POSSIBILITY OF A QUICK SOUTHERN FORECAST AREA POP
UP SHOWER OR ISOLATED STORM FORM JUST ALONG ITS LEADING EDGE...ALONG
WITH THE BRIEF FORMATION OF LOW DECKS OR HAZE JUST DOWNSTREAM OF
THE FRONT. IN THE WAKE OF THIS BOUNDARY THE ADVECTION OF A NORTHEASTERN
DRY AIR MASS WILL LOWER INTERIOR DEW POINTS 20 TO 25 DEGREES...TO
AROUND 10 DEGREES AT COAST...BY THIS TIME TOMORROW. THUS...A MOSTLY
SUNNY AND WARM DAY WITH A (N-NE) INLAND BREEZE...A SLIGHT CHANCE
FOR JUST SCATTERED SHOWERS IN THE VICINITY OF THE OFFSHORE FRONT
PROVIDING FOCUS WITHIN HIGHER MOISTURE. SLIGHTLY BELOW NORMAL WARMTH
IN THE MID TO UPPER 80S TOMORROW TRANSITIONS TO A COOL...DRY SUNDAY
MORNING. THE CURRENT AUTUMN-LIKE FORECAST HAS SUNDAY MINIMUM TEMPERATURES
IN THE UPPER 50S TO LOWER 60S (INLAND)...LOW TO MID 70S CLOSER TO
THE COAST. 31
&&
.PREV DISCUSSION... /ISSUED /
AVIATION...
BULK OF RAINFALL HAS PUSHED OFF THE COAST. STILL SOME LINGERING
1500FT CIGS ACROSS SOUTHERN TERMINALS BUT SUSPECT THESE WILL LIFT
IN THE NEXT FEW HOURS AND BE LEFT WITH SOME SCT/BKN CIRRUS.
FRONTAL BOUNDARY IS SITUATED JUST NORTH OF SE TX AT THIS TIME AND
WILL BE SAGGING SOUTHWARD AND OFF THE COAST TOWARD SUNRISE. MAY
SEE A FEW ISO SHRA ALONG THE BOUNDARY BUT PROBABLY NOT WORTH
MENTIONING AS MOST OF THE AREA IS PRETTY WORKED OVER FROM EARLIER
RAINS. WILL ALSO BE ON THE LOOKOUT FOR PATCHY FOG DEVELOPMENT
PRIOR TO THE ARRIVAL OF THE DRIER AIR. BUT...SHOULD SEE VFR
CONDITIONS AREAWIDE AROUND SUNRISE WHICH WILL PERSIST THRU THE DAY
SAT. 47
PREV DISCUSSION...
SHOWER AND THUNDERSTORM ACTIVITY CONTINUES TO COME TO AN END THIS
AFTERNOON AFTER THUNDERSTORM ACTIVITY HAS DUMPED 1 TO 2 INCHES OF
RAIN MAINLY SOUTH OF A BRENHAM TO CLEVELAND LINE. NORTH OF THAT
LINE AREAS HAVE GOTTEN VERY LITTLE RAINFALL AND THOSE ARE THE
AREAS THAT NEED IT. AREAS OF W HARRIS CO THAT DO NOT NEED THE RAIN
ENDED UP WITH ANYWHERE FROM 3 TO 6 INCHES OF RAIN CAUSING
LOCALIZED FLOODING MAINLY ON THE SOUTH MAYDE CREEK.
LATEST RADAR TRENDS SHOW PRECIPITATION ENDING BUT ALSO NOTICED
GRAVITY WAVES WORKING SOUTH. SURFACE COLD FRONT AT 20Z OR 3PM
LOOKS TO BE PUSHING THROUGH N TEXAS WITH A PRE-FRONTAL TROUGH
AHEAD OF IT. WATER VAPOR IMAGERY SHOWS A WELL DEVELOPED LONG WAVE
TROUGH STRETCHING FROM AN UPPER LOW OVER S HUDSON BAY. ONE
ELONGATED TROUGH AXIS STRETCHED W TO E ACROSS THE AREA WITH A
SECOND STRONGER TROUGH AXIS THROUGH THE S PLAINS. AMPLIFIED
PATTERN WILL SUPPORT COLD FRONTAL PASSAGE THROUGH THE AREA LATE
TONIGHT INTO SATURDAY MORNING. POSSIBLE THAT A FEW STORMS COULD
FORM ON THE FRONT TONIGHT PER LATEST HRRR MODEL TRENDS SO WILL
KEEP SOME RAIN CHANCES IN THE FORECAST. OTHERWISE RAIN CHANCES
SHOULD DECREASE THROUGH SATURDAY MORNING WITH A DRIER AIRMASS
ARRIVING DURING THE DAY. SURFACE DEWPOINTS COULD DROP INTO THE 40S
LATE SATURDAY AFTERNOON AND OVERNIGHT. MIN TEMPS SUNDAY MORNING
WILL BE QUITE COOL IN THE LOW 60S FOR MOST AREAS AND PERHAPS 50S
FOR AREAS NORTH OF HOUSTON. THE SAME WILL BE POSSIBLE MONDAY. IN
OTHER WORDS GET OUT AND ENJOY THE FALL LIKE WEATHER.
EXTENDED FORECAST...
THE FORECAST FOR TUE THROUGH FRI NEXT WEEK HAS BEEN CHALLENGING
WITH THE GFS REMAINING MOSTLY CONSISTENT AND THEN THE ECMWF
PRODUCING EITHER A HURRICANE OR NOW JUST A THUNDERSTORM IN THE
GULF. IT DOES LOOK LIKE THE 12Z GFS/ECMWF ARE IN MORE AGREEMENT.
BOTH MODELS SHOW THAT A WEAK AREA OF LOW PRESSURE OR COASTAL
TROUGH COULD FORM IN THE W GULF AND BAY OF CAMPECHE MONDAY INTO
TUESDAY. AS THE SURFACE LOW OR COASTAL TROUGH MOVES
NORTH...MOISTURE SHOULD INCREASE OVER THE AREA MID WEEK BUT IT
DOES NOT LOOK AS ROBUST AS BEFORE. PRECIP WATER VALUES MAY REACH
1.7-1.8 INCHES INSTEAD OF OVER 2 INCHES IN PRIOR MODEL RUNS. SO
RAIN CHANCES WERE TRIMMED A BIT BUT STILL THINK THERE MAY BE A
DECENT CHANCE OF AT LEAST SCATTERED SHOWER AND THUNDERSTORM
ACTIVITY FOR THE MID WEEK. TEMPERATURES WILL BE MORE CLOSER TO
NORMAL WITH HIGH TEMPS IN THE LOW 90S AND LOWS IN THE 70S. WITH
ALL THAT SAID...CONFIDENCE IS PRETTY LOW THAT THERE WILL BE ANY
TROPICAL DEVELOPMENT BASED ON CURRENT FORECAST TRENDS. 39
AVIATION...
BACK EDGE OF THIS MORNINGS PCPN MAKING SLOW PROGRESS SWD WITH IFR TO
LIFR CIGS PERSISTING OVER THE SRN SITES. ALSO STILL SEEING ISO SHRAS
REDEVELOPING OVER THE NRN HALF OF THE CWA (ALONG THE PREFRONTAL TROF
SLOWLY NUDGING IN FROM THE NORTH). LIGHT NORTH WINDS EXPECTED IN THE
WAKE OF THIS BOUNDARY THIS EVE AS IT MOVES TOWARD THE COAST. HOWEVER
WITH THE ACTUAL COLD FRONT LAGGING THIS INITIAL LINE BY A FEW HRS...
WE COULD SEE SOME BRIEF PATCHY BR DEVELOP OVERNIGHT. OTHERWISE...VFR
CONDITIONS TO PREVAIL ONCE THIS PCPN MOVES OUT. 41
MARINE...
WIDESPREAD SHOWERS/THUNDERSTORMS TO PERSIST ACROSS THE MARINE WATERS
THIS EVENING AS THE STRONG DISTURBANCE MOVES OFFSHORE. RAIN CHC WILL
LIKELY LINGER OVERNITE AS THE PREFRONTAL TROF APPROACHES FROM THE N.
THE MAIN COLD FRONT IS STILL PROGGED TO PUSH OFFSHORE EARLY SAT MORN
WITH LIGHT/MODERATE NE FLOW DEVELOPING SAT AFTN THRU SUN. AS THE SFC
HIGH NUDGES EAST OF THE STATE...WE SHOULD EXPECT A MORE EASTERLY LOW
LEVEL FLOW BY SUN NIGHT. MARINE WINDS TO BECOME MORE SELY DURING THE
START OF NEXT WEEK WITH PERIODS OF UNSETTLED WX RETURNING AS WELL.
41
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 71 87 61 87 64 / 10 10 0 0 0
HOUSTON (IAH) 73 88 61 85 64 / 20 10 0 0 0
GALVESTON (GLS) 77 87 73 84 74 / 20 10 0 10 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...31
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
622 PM CDT FRI SEP 11 2015
.AVIATION...
BULK OF RAINFALL HAS PUSHED OFF THE COAST. STILL SOME LINGERING
1500FT CIGS ACROSS SOUTHERN TERMINALS BUT SUSPECT THESE WILL LIFT
IN THE NEXT FEW HOURS AND BE LEFT WITH SOME SCT/BKN CIRRUS.
FRONTAL BOUNDARY IS SITUATED JUST NORTH OF SE TX AT THIS TIME AND
WILL BE SAGGING SOUTHWARD AND OFF THE COAST TOWARD SUNRISE. MAY
SEE A FEW ISO SHRA ALONG THE BOUNDARY BUT PROBABLY NOT WORTH
MENTIONING AS MOST OF THE AREA IS PRETTY WORKED OVER FROM EARLIER
RAINS. WILL ALSO BE ON THE LOOKOUT FOR PATCHY FOG DEVELOPMENT
PRIOR TO THE ARRIVAL OF THE DRIER AIR. BUT...SHOULD SEE VFR
CONDITIONS AREAWIDE AROUND SUNRISE WHICH WILL PERSIST THRU THE DAY
SAT. 47
&&
.PREV DISCUSSION...
SHOWER AND THUNDERSTORM ACTIVITY CONTINUES TO COME TO AN END THIS
AFTERNOON AFTER THUNDERSTORM ACTIVITY HAS DUMPED 1 TO 2 INCHES OF
RAIN MAINLY SOUTH OF A BRENHAM TO CLEVELAND LINE. NORTH OF THAT
LINE AREAS HAVE GOTTEN VERY LITTLE RAINFALL AND THOSE ARE THE
AREAS THAT NEED IT. AREAS OF W HARRIS CO THAT DO NOT NEED THE RAIN
ENDED UP WITH ANYWHERE FROM 3 TO 6 INCHES OF RAIN CAUSING
LOCALIZED FLOODING MAINLY ON THE SOUTH MAYDE CREEK.
LATEST RADAR TRENDS SHOW PRECIPITATION ENDING BUT ALSO NOTICED
GRAVITY WAVES WORKING SOUTH. SURFACE COLD FRONT AT 20Z OR 3PM
LOOKS TO BE PUSHING THROUGH N TEXAS WITH A PRE-FRONTAL TROUGH
AHEAD OF IT. WATER VAPOR IMAGERY SHOWS A WELL DEVELOPED LONG WAVE
TROUGH STRETCHING FROM AN UPPER LOW OVER S HUDSON BAY. ONE
ELONGATED TROUGH AXIS STRETCHED W TO E ACROSS THE AREA WITH A
SECOND STRONGER TROUGH AXIS THROUGH THE S PLAINS. AMPLIFIED
PATTERN WILL SUPPORT COLD FRONTAL PASSAGE THROUGH THE AREA LATE
TONIGHT INTO SATURDAY MORNING. POSSIBLE THAT A FEW STORMS COULD
FORM ON THE FRONT TONIGHT PER LATEST HRRR MODEL TRENDS SO WILL
KEEP SOME RAIN CHANCES IN THE FORECAST. OTHERWISE RAIN CHANCES
SHOULD DECREASE THROUGH SATURDAY MORNING WITH A DRIER AIRMASS
ARRIVING DURING THE DAY. SURFACE DEWPOINTS COULD DROP INTO THE 40S
LATE SATURDAY AFTERNOON AND OVERNIGHT. MIN TEMPS SUNDAY MORNING
WILL BE QUITE COOL IN THE LOW 60S FOR MOST AREAS AND PERHAPS 50S
FOR AREAS NORTH OF HOUSTON. THE SAME WILL BE POSSIBLE MONDAY. IN
OTHER WORDS GET OUT AND ENJOY THE FALL LIKE WEATHER.
EXTENDED FORECAST...
THE FORECAST FOR TUE THROUGH FRI NEXT WEEK HAS BEEN CHALLENGING
WITH THE GFS REMAINING MOSTLY CONSISTENT AND THEN THE ECMWF
PRODUCING EITHER A HURRICANE OR NOW JUST A THUNDERSTORM IN THE
GULF. IT DOES LOOK LIKE THE 12Z GFS/ECMWF ARE IN MORE AGREEMENT.
BOTH MODELS SHOW THAT A WEAK AREA OF LOW PRESSURE OR COASTAL
TROUGH COULD FORM IN THE W GULF AND BAY OF CAMPECHE MONDAY INTO
TUESDAY. AS THE SURFACE LOW OR COASTAL TROUGH MOVES
NORTH...MOISTURE SHOULD INCREASE OVER THE AREA MID WEEK BUT IT
DOES NOT LOOK AS ROBUST AS BEFORE. PRECIP WATER VALUES MAY REACH
1.7-1.8 INCHES INSTEAD OF OVER 2 INCHES IN PRIOR MODEL RUNS. SO
RAIN CHANCES WERE TRIMMED A BIT BUT STILL THINK THERE MAY BE A
DECENT CHANCE OF AT LEAST SCATTERED SHOWER AND THUNDERSTORM
ACTIVITY FOR THE MID WEEK. TEMPERATURES WILL BE MORE CLOSER TO
NORMAL WITH HIGH TEMPS IN THE LOW 90S AND LOWS IN THE 70S. WITH
ALL THAT SAID...CONFIDENCE IS PRETTY LOW THAT THERE WILL BE ANY
TROPICAL DEVELOPMENT BASED ON CURRENT FORECAST TRENDS. 39
AVIATION...
BACK EDGE OF THIS MORNINGS PCPN MAKING SLOW PROGRESS SWD WITH IFR TO
LIFR CIGS PERSISTING OVER THE SRN SITES. ALSO STILL SEEING ISO SHRAS
REDEVELOPING OVER THE NRN HALF OF THE CWA (ALONG THE PREFRONTAL TROF
SLOWLY NUDGING IN FROM THE NORTH). LIGHT NORTH WINDS EXPECTED IN THE
WAKE OF THIS BOUNDARY THIS EVE AS IT MOVES TOWARD THE COAST. HOWEVER
WITH THE ACTUAL COLD FRONT LAGGING THIS INITIAL LINE BY A FEW HRS...
WE COULD SEE SOME BRIEF PATCHY BR DEVELOP OVERNIGHT. OTHERWISE...VFR
CONDITIONS TO PREVAIL ONCE THIS PCPN MOVES OUT. 41
MARINE...
WIDESPREAD SHOWERS/THUNDERSTORMS TO PERSIST ACROSS THE MARINE WATERS
THIS EVENING AS THE STRONG DISTURBANCE MOVES OFFSHORE. RAIN CHC WILL
LIKELY LINGER OVERNITE AS THE PREFRONTAL TROF APPROACHES FROM THE N.
THE MAIN COLD FRONT IS STILL PROGGED TO PUSH OFFSHORE EARLY SAT MORN
WITH LIGHT/MODERATE NE FLOW DEVELOPING SAT AFTN THRU SUN. AS THE SFC
HIGH NUDGES EAST OF THE STATE...WE SHOULD EXPECT A MORE EASTERLY LOW
LEVEL FLOW BY SUN NIGHT. MARINE WINDS TO BECOME MORE SELY DURING THE
START OF NEXT WEEK WITH PERIODS OF UNSETTLED WX RETURNING AS WELL.
41
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 73 87 61 87 64 / 30 10 10 0 0
HOUSTON (IAH) 73 88 61 85 64 / 20 10 10 0 0
GALVESTON (GLS) 77 87 73 84 74 / 30 20 10 10 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
353 PM CDT THU SEP 10 2015
.DISCUSSION...
RADAR THIS AFTERNOON SHOWS WIDESPREAD SHOWER AND THUNDERSTORM
ACTIVITY WITH THE STRONGEST STORMS OVER E HARRIS COUNTY WHERE
STORMS ARE PRODUCING RAIN RATES OF 2 INCHES AN HOUR. THERE IS ALSO
A BAND OF ACTIVITY ALONG A STALLED FRONTAL BOUNDARY FROM AUSTIN TO
COLLEGE STATION EAST TO JASPER. LATEST TRENDS WITH THE HRRR MODEL
SEEM TO SHOW ACTIVITY ENDING BETWEEN 00-03Z THIS EVENING.
WATER VAPOR IMAGE LOOP SHOWS A WEAK JET STREAK/SHORTWAVE PUSHING
THROUGH THE REGION THIS AFTERNOON WHICH MAY BE HELPING TO ENHANCE
CONVECTION. OVERALL UPPER LEVEL PATTERN IS ON TRACK WITH A
STRONGER SHORTWAVE TROUGH DEVELOPING OVER THE N ROCKIES WHICH WILL
HELP AMPLIFY THE TROUGH FROM SW OF HUDSON BAY TO THE UPPER
MIDWEST TONIGHT INTO FRIDAY.
WITH PRECIP WATER VALUES OVER 2 INCHES TOMORROW AND FAVORABLE
UPPER LEVEL PATTERN...FORECAST WILL HOLD ONTO 60/70 POPS.
GFS/NAM/ECMWF ALL SUPPORT SHOWER AND THUNDERSTORM ACTIVITY SIMILAR
TO TODAY`S ACTIVITY. THERE WILL ALSO BE AN ADDED TROUGH AXIS THAT
PUSHES THROUGH FRI TO HELP INCREASE LARGE SCALE LIFT. AS HAS BEEN
THE CASE TODAY...EXPECTING A GENERAL 1 TO 2 INCHES OF RAIN WITH
ISOLATED HIGHER AMOUNTS. SINCE CONVECTION WILL BE PULSE
TYPE...VERY WELL COULD HAVE AREAS THAT GET NO RAINFALL BUT THEN
AREAS THAT GET TOO MUCH. THERE MAY BE FLOODING ASSOCIATED WITH ANY
OF THE HIGHER AMOUNTS BUT A WIDESPREAD FLOOD THREAT IS NOT
EXPECTED AT THIS TIME.
GIVEN THE MORE AMPLIFIED PATTERN FRIDAY INTO SATURDAY...COLD FRONT
WILL BE PUSHING THROUGH THE AREA AND OFF THE COAST. LATEST TIMING
FROM THE NAM/GFS/ECMWF SHOWS IT REACHING COLLEGE
STATION TO HUNTSVILLE AROUND 1-3AM SATURDAY...REACHING HOUSTON
CLOSER TO 6-8AM AND OFF THE COAST BEFORE NOON SATURDAY. WINDS
SHOULD SHIFT TO THE N/NE. THE MUCH DRIER COOLER AIRMASS WILL
LIKELY LAG BEHIND THE FRONT AND NOT ARRIVE UNTIL LATER IN THE
AFTERNOON AND OVERNIGHT. THERE DOES NOT APPEAR TO BE MUCH OF A
CHANCE OF THUNDERSTORMS WITH THE FRONT BUT GIVEN THE MOISTURE
CONTENT WILL AT LEAST HAVE A 30 PERCENT IN THE FORECAST.
WEATHER CONDITIONS SUNDAY/MONDAY WILL CERTAINLY GIVE EVERYONE A
GOOD TASTE OF FALL WEATHER WITH LOW TEMPS IN THE LOW 60S...PERHAPS
UPPER 50S FOR AREAS NORTH OF HOUSTON. HIGH TEMPERATURES WILL BE
IN THE MID 80S. ENJOY IT WHILE YOU CAN BECAUSE THE MOISTURE SHOULD
BE BACK TUESDAY THROUGH THURSDAY NEXT WEEK.
EXTENDED FORECAST...STILL VERY UNCERTAIN WITH REGARDS TO A SURGE
OF TROPICAL MOISTURE EXPECTED TO PUSH INTO THE AREA TUESDAY AND
WEDNESDAY. GFS HAS BEEN VERY CONSISTENT AND HAS HAD ENSEMBLE
SUPPORT OF MAINLY A SURFACE COASTAL TROUGH DEVELOPING IN THE W
GULF AND PUSHING NORTH TOWARDS THE AREA. THE ECMWF THE LAST 2 RUNS
HAS NOW TAPPED THE BREAKS ON TROPICAL CYCLONE FORMATION ALTHOUGH
IT STILL WANTS TO DEVELOP SOME TYPE OF LOW PRESSURE WHICH IT
SLOWLY PUSHES TOWARDS THE LOWER TEXAS COAST NEXT WEEK. GFS
CONTINUES TO HOLD ONTO SOME W SHEAR ACROSS THE N GULF WITH THE
ECMWF STILL HAVING SOMEWHAT OF A RIDGE. THE DIFFERENCES IN THE
PATTERNS WILL LIKELY DETERMINE HOW MUCH SHEAR DEVELOPS OVER THE NW
GULF AND IF THERE IS ANY DEVELOPMENT. AT THIS POINT IT DOES NOT
LOOK LIKELY BUT WE WILL STILL NEED TO MONITOR FORECAST DATA.
39
&&
.AVIATION...
FAIRLY ACTIVE AFTN WITH CONVECTION FILLING IN. MODELS INDICATE PER-
HAPS ANOTHER DAY OF UNSETTLED WX TOMORROW. WILL START WITH VCSH FOR
THE MORNING HRS THEN TRANSITIONING TO VCTS FOR THE AFTN. BUT IN THE
MEANTIME...MAY HAVE TO INCLUDE A BRIEF MVFR CIG FOR NRN SITES GIVEN
THE WIDESPREAD RAINS/EXPECTED CLEARING OVERNIGHT. 41
&&
.MARINE...
NOT TOO MANY CHANGES WITH THE SHORT TERM PART OF THE FCST AS MOSTLY
LIGHT ONSHORE WINDS PREVAIL...ALONG WITH THE WIDESPREAD STORMS THRU
TOMORROW(FRI). MODELS STILL IN DECENT AGREEMENT WITH THE PASSAGE OF
A WEAK COLD FRONT INTO THE COASTAL WATERS EARLY SAT MORNING. GENER-
ALLY LIGHT/MODERATE NE WINDS TO DEVELOP IN ITS WAKE...FROM SAT AFTN
INTO SUN MORNING. AS THIS FRONT DISSIPATES OVER THE GULF AND A WEAK
TROF OF LOW PRESSURE BEGINS TO DEVELOP NEAR THE LOWER TX COAST...WE
SHOULD START SEEING A MORE EASTERLY FETCH DEVELOP OVER THE UPPER TX
COAST SUN AFTN/EVE. THIS FEATURE WILL THEN HELP TO BRING PERIODS OF
SHRA/TSRA AND PERHAPS A PROLONGED PERIOD OF ESE WINDS TO THE REGION
FOR THE FIRST HALF OF NEXT WEEK. 41
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 74 89 71 86 61 / 30 40 30 10 10
HOUSTON (IAH) 74 87 71 86 62 / 40 60 30 20 10
GALVESTON (GLS) 78 84 76 86 72 / 50 70 50 30 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...39
AVIATION/MARINE...41
AREA FORECAST DISCUSSION
NWS CORPUS CHRISTI TX
334 PM CDT THU SEP 10 2015
.SHORT TERM (TONIGHT THROUGH FRIDAY NIGHT)...ABUNDANT MOISTURE
WITH OVER 2 INCH PWATS REMAINS OVER SOUTH TEXAS WITH SCATTERED
CONVECTION ONGOING...WITH CONVECTION EXPECTED TO DWINDLE THROUGH
THE EVENING. CHALLENGE GOES INTO TIMING OF CONVECTION FOR FRIDAY.
TEXAS TECH WRF AND HRRR BOTH HAVE HAD A PRETTY GOOD HOLD
CONVECTION TODAY...AND LOOKING AT WHAT THEY SHOW FOR FRIDAY...THEY
KEEP A MUCH SLOWER TREND FOR CONVECTION...WITH THINGS MOSTLY DRY
THROUGH MID MORNING FRIDAY. DUE TO AN INCREASE IN H925 FLOW AND A
SHORTWAVE MOVING SOUTH ALONG THE RIO GRANDE OVERNIGHT KEPT IN POPS
FOR TONIGHT...BUT DUE TO A BIT OF SUBSIDENCE AHEAD OF THE
SOUTHWARD PROGRESSING TROUGH...DID CUT BACK FROM PREVIOUS
FORECAST PACKAGE. CHANCES FOR RAIN WILL INCREASE THROUGH THE
DAY...WITH THE BEST TIMING MORE DURING THE AFTERNOON THROUGH
OVERNIGHT HOURS...DUE TO MORE CONVERGENCE AND INCREASED LIFT WITH
THE TROUGH SHIFTING SOUTH. AS FOR TEMPERATURES...TRENDED ON THE
COOLER SIDE FROM THE EXPECTED CLOUD COVERAGE AND RAIN CHANCES.
&&
.LONG TERM (SATURDAY THROUGH THURSDAY)...THE MODELS ARE FAIRLY
CONSISTENT IN PUSHING A COLD FRONT THROUGH THE CWA BY SATURDAY
NIGHT. SUFFICIENT MOISTURE/INSTABILITY AND KINEMATIC FORCING WL
EXIST ALONG AND AHEAD OF THE FRONT TO MAINTAIN SLIGHT CHC TO CHC
POPS ON SATURDAY. DRY AIR ADVECTION AIDED BY A WK TO MODERATE
NORTHEAST FLOW WL PRODUCE ABUNDANT SUNSHINE AND MUCH LOWER
HUMIDITIES FOR SUNDAY. THE ECMWF 12Z SOLUTION HAS NOW COME MORE IN
LINE WITH THE WEAKER GFS REFLECTION OF THE AREA OF LOW PRESSURE THAT
MAY DEVELOP OVER THE SW GULF BY SUNDAY AND MONDAY. THE CURRENT
THINKING IS THAT THIS SYSTEM WL REMAIN WK AND REMAIN TO OUR SOUTH
POSSIBLY MOVING INTO NORTHERN MEXICO NEAR TAMPICO BY TUESDAY. THE
NET EFFECT WL LKLY BE TO KEEP MOST OF THE DEEP TROPICAL MOISTURE TO
THE SOUTH. HOWEVER...DO EXPECT MOISTURE TRANSPORT NEXT WEEK AS THE
BOUNDARY LAYER FLOW BECOMES MORE SOUTHEASTERLY BY MONDAY. THERE WL
LKLY BE SUFFICIENT MOISTURE TO WARRANT SLIGHT CHC TO CHC POPS FOR
MOSTLY THE WATERS AND COASTAL BEND FROM LATE MONDAY THROUGH
THURSDAY. OVERALL DID TRIM THESE POPS BACK FOR NEXT WEEK FROM PRIOR
REASONING. SLIGHTLY BELOW NORMAL TEMPS ARE EXPECTED DURING THE
WEEKEND AND THEN WL SLOWLY TRANSITION TO MORE NORMAL MID SEPTEMBER
VALUES THROUGH NEXT WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 78 89 74 88 71 / 40 60 60 40 20
VICTORIA 74 86 71 87 64 / 40 60 40 20 10
LAREDO 78 93 73 90 71 / 40 60 60 30 20
ALICE 75 90 72 88 68 / 40 60 60 40 20
ROCKPORT 79 87 75 87 72 / 40 60 60 40 20
COTULLA 76 90 73 91 67 / 40 60 40 20 10
KINGSVILLE 77 91 73 88 70 / 40 60 60 40 20
NAVY CORPUS 79 87 76 87 74 / 40 60 60 40 20
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
CB/85...SHORT TERM
MB/80...LONG TERM
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
304 PM CDT THU SEP 10 2015
.SHORT TERM...
A PROMINENT FEATURE IN THE WEATHER TODAY HAS BEEN A BAND OF CIRRUS
ARCING FROM CENTRAL ARIZONA ACROSS WEST TEXAS. THIS IS ASSOCIATED
WITH SOME TROPICAL MOISTURE CAUGHT UP IN THE CIRCULATION OF DECAYING
TROPICAL STORM LINDA OFF THE WEST COAST OF BAJA. UPPER-AIR ANALYSIS
SHOWS THAT THIS MOISTURE IS LIMITED TO THE UPPER TROPOSPHERE WITH
MID-LEVELS REMAINING FAIRLY DRY AND UNSUPPORTIVE OF ANY CONVECTIVE
DEVELOPMENT. HOWEVER...WE ARE SEEING SOME DEVELOPMENT ACROSS NORTH-
CENTRAL NEW MEXICO IN VICINITY OF THE RATON MESA. NORTHWEST FLOW
ALOFT WILL CARRY THIS ACTIVITY TO THE SOUTHEAST THIS EVENING TOWARD
THE FAR SOUTHWEST TEXAS PANHANDLE ASSUMING IT SURVIVES THE TREK
ACROSS THE NORTHEAST NEW MEXICO PLAINS. THE HRRR IS ABOUT THE THE
ONLY MODEL THAT INDICATES THIS...BUT WE WILL MAINTAIN A SLIGHT
CHANCE MENTION ACROSS MUCH OF THE SRN TX PANHANDLE BETWEEN 00 AND 06
UTC TO ACCOUNT FOR THIS POSSIBILITY. BETTER T-STORM/RAIN CHANCES
SHOULD ARRIVE EARLY FRIDAY MORNING AS A FAIRLY SHARP COLD FRONT
MOVES IN FROM THE NORTH IN CONJUNCTION WITH A GLANCING BLOW FROM A
SHORTWAVE MOVING SOUTHEAST THROUGH THE PLAINS. THE FRONT IS
CURRENTLY MOVING INTO NORTHERN KANSAS AND THERE IS SOME UNCERTAINTY
REGARDING IT/S TIMING INTO OUR FORECAST AREA OWING TO THE IMPACT OF
CONVECTIVE OUTFLOWS ON THE FRONT. IN ADDITION...IT IS UNCERTAIN
WHETHER OR NOT THE FRONTOGENETIC FORCING WILL SYNCH UP WITH THE BEST
LARGE-SCALE ASCENT ASSOCIATED WITH THE PASSING WAVE. FINALLY...THE
TIMING OF THE FRONT...PASSING THROUGH THE AREA ROUGHLY BETWEEN 12
UTC AND 18 UTC...IS NOT OPTIMAL FOR THE GENERATION OF INSTABILITY
AVAILABLE FOR CONVECTION. WITH THIS IN MIND...WE HAVE KEPT POPS IN
THE CHANCE CATEGORY FOR THE AREA ON FRIDAY AS THE LINGERING
UNCERTAINTY DOES LEND ITSELF FOR LIKELY OR CATEGORICAL POPS. IN
GENERAL...GUIDANCE FAVORS A BROAD ZONE OR CLUSTER OF ALONG AND POST-
FRONTAL SHOWERS AND THUNDERSTORMS FRIDAY MORNING FOLLOWING THE FRONT
FROM NORTHEAST TO SOUTHWEST....AND GRADUALLY TAPERING OFF FROM THE
NORTHEAST DURING THE AFTERNOON. BREEZY NORTHEAST WINDS WILL DEVELOP
BEHIND THE FRONT AND LAST THROUGH THE AFTERNOON. TEMPERATURES WILL
BE MARKEDLY COOLER ACROSS THE NORTH...WITH HIGHS IN THE MID TO UPPER
70S ACROSS THE FAR SW TEXAS PANHANDLE AND NORTHERN SOUTH PLAINS.
DEPENDING ON THE TIMING OF THE FRONT...WE MAY STILL STILL SOME HIGH
TEMPS REACH 90 DOWN IN THE SOUTHERN ROLLING PLAINS.
.LONG TERM...
MID-LEVEL DRYING WILL ADVANCE SLOWLY SW BY FRIDAY EVENING IN THE
WAKE OF THE 850-700 MB COLD FRONT. THE DRIEST SURFACE RIDGING WILL
LAG UNTIL SATURDAY MORNING...SO POST-FRONTAL STRATUS AIDED BY E-NE
WINDS SHOULD LINGER ESPECIALLY ON THE CAPROCK BEFORE ERODING BY
MIDDAY SAT. SOME OF THIS STRATUS IS PROGGED TO BE SUFFICIENTLY THICK
FRI NIGHT THAT A FEW SHOWERS COULD MATERIALIZE FROM WEAK FN FORCING
ALONG THE AFOREMENTIONED ELEVATED FRONTAL LAYER...BUT POPS OVERALL
WERE SKIMMED BACK EVEN FURTHER THAN BEFORE.
SAT MORNING WILL SEE SURFACE WINDS VEER SELY BEHIND THE PROGRESSIVE
SURFACE RIDGE AND THIS PROCESS WILL AID IN WEAK ISENTROPIC LIFT
ACROSS THE WESTERN HALF OF THE CWA COINCIDENT WITH A MODEST AXIS OF
HIGHER PWATS. WHILE SATURATED DEPTHS ARE NOT MUCH TO WRITE ABOUT...
THE BRUNT OF THIS SATURATION IS BELOW 700 MB WHICH COULD BE WRUNG
OUT IN THE FORM OF SPRINKLES OR EVEN DRIZZLE PROVIDED STRATUS CAN
DESCEND LOW ENOUGH AT TIMES. CLEARING SKIES BY MIDDAY COULD OPEN THE
DOOR TO WEAK CAPE ACROSS EASTERN NM UNDERNEATH 10-20 KNOTS OF NW
FLOW...HOWEVER NO DISCERNIBLE BACKGROUND SUPPORT PRECLUDES FURTHER
POPS AT THIS TIME. EVEN WITH CLEARING...BELOW NORMAL HIGHS REMAIN ON
TRACK GIVEN OUR PROXIMITY TO THE SURFACE RIDGE. THIS COOL THEME WILL
BE SHORT LIVED AS SUNDAY AND BEYOND FEATURE LEE TROUGHING BENEATH
AMPLIFYING SW FLOW. SIDED CLOSE TO THE WARMEST MEX AND ECE MOS HIGHS
NEXT WEEK AS THIS LOOKS TO BE A VERY DRY AND BREEZY PATTERN FOR WEST
TX. SUCH DRY SOILS IN THIS SETUP ARGUE IN FAVOR OF A RATHER STRONG
DIURNAL TEMP RANGE...SO LOWS WERE NUDGED BELOW THE MILD SUPERBLEND
VALUES.
A SMALL WINDOW FOR MID-LEVEL MOISTENING MAY UNFOLD NEAR MIDWEEK AS A
BROAD TROUGH LIFTS NORTHEAST OUT OF THE FOUR CORNERS. MONSOONAL
MOISTURE ALOFT WILL LIKELY BE THINNED OUT BY THIS TIME...BUT SOME
UPTICK IN PWATS MAY BE REALIZED BY TUE AND WED AS THE SW FLOW TURNS
WEAKLY CYCLONIC. WHETHER THIS RESULTS IN PRECIP ALONG A DRYLINE
IN/NEAR OUR AREA IS TOO UNCERTAIN...ESPECIALLY WITH OUR REGION
RESIDING LARGELY SOUTH OF THE UPPER JET MAXIMA.
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
33/93
AREA FORECAST DISCUSSION...UPDATED
NWS BROWNSVILLE TX
1235 PM CDT THU SEP 10 2015
.DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.
&&
.AVIATION...SHOWERS BEGINNING TO FORM ALONG THE COAST ATTM...WITH
GENERAL NORTHWARD MOVEMENT. EXPECT A COUPLE SHOWERS COULD REACH
KBRO AND KHRL EARLY THIS AFTERNOON...WITH BRIEF AND MINIMAL
CHANGES TO FLIGHT CONDITIONS. SKIES SHOULD REMAIN MOSTLY CLEAR
THROUGH THE NIGHT UNTIL JUST BEFORE DAWN. LOW CLOUDS MAY THICKEN
BETWEEN 09 AND 13Z...SO HAVE ADDED TEMPO GROUPS. MORE WIDESPREAD
SHOWERS AND THUNDERSTORMS LIKELY TO ARRIVE LATER TOMORROW
AFTERNOON AT LOCAL AIRPORTS.
&&
.PREV DISCUSSION... /ISSUED 556 AM CDT THU SEP 10 2015/
DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.
AVIATION...LIGHT SOUTHEAST WINDS WITH A FEW PASSING CLOUDS
PREVAIL OVER DEEP SOUTH TEXAS THIS MORNING. SOME PATCHY LIGHT FOG
AND LOW CLOUD DECKS HAVE BEEN OBSERVED ACROSS THE REGION IN THE
PAST COUPLE OF HOURS. BRIEF MVFR CONDITIONS WILL BE POSSIBLE JUST
AFTER SUNRISE. OTHERWISE...VFR CONDITIONS EXPECTED THROUGH THIS
LATE EVENING. WILL KEEP THE MENTION OF VCSH AT ALL TAF SITES AS
ISOLATED SEA BREEZE ACTIVITY IS POSSIBLE LATER TODAY. LIGHT
SOUTHEAST WINDS WILL BECOME MODERATE LATER THIS MORNING WITH GUSTS
AROUND 20 KNOTS IN THE AFTERNOON. WINDS WILL GRADUALLY WEAKEN THIS
EVENING WITH INCREASING LOW CLOUDS LATE TONIGHT.
PREV DISCUSSION... /ISSUED 422 AM CDT THU SEP 10 2015/
SHORT TERM /NOW THROUGH FRIDAY/...LATEST WATER VAPOR SATELLITE
IMAGERY SHOWS A 500MB RIDGE CENTERED OVER WEST TEXAS INTO NORTHERN
MEXICO AND OVER SOUTH FLORIDA WITH 500MB WEAKNESS OVER THE WESTERN
GULF OF MEXICO. BROWNSVILLE RADAR SHOWS ISOLATED ACTIVITY ACROSS THE
LOWER TEXAS GULF WATERS THIS MORNING. THE LATEST HRRR SUGGESTS
CONVECTION WILL INCREASE ACROSS THE GULF WATERS THROUGH SUNRISE. BRO
SOUNDING FROM WEDNESDAY EVENING INDICATES PRECIPITABLE WATER VALUES
OF 1.87 INCHES. EXCEPT FOR SOME PASSING HIGH CLOUDS...MOSTLY CLEAR
SKIES AND LIGHT WINDS PREVAIL ACROSS DEEP SOUTH TEXAS EARLY THIS
MORNING. A LITTLE GROUND FOG MAY DEVELOP AROUND SUNRISE BEFORE
QUICKLY DISSIPATING. NOTE...THE SURFACE OBSERVATION FROM EDINBURG IS
NOT REPRESENTATIVE TO CURRENT WEATHER CONDITIONS.
THE MAIN FORECAST ISSUE WILL BE THE RAIN CHANCES ACROSS DEEP SOUTH
TEXAS THROUGH THE FORECAST PERIOD. DEEP TROPICAL MOISTURE
/PRECIPITABLE WATER VALUES IN EXCESS OF 2 INCHES/ COMBINED WITH DAY
TIME HEATING WILL SUPPORT ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS TODAY. HIGH TEMPERATURES TODAY WILL RANGE FROM THE
LOWER 90S NEAR THE COAST TO THE UPPER 90S ACROSS THE UPPER VALLEY.
RAIN CHANCES MAY LINGER ACROSS THE NORTHERN RANCHLANDS TONIGHT AS
THE GFS SUGGESTS. OTHERWISE...MOSTLY CLOUDY SKIES WITH LOW
TEMPERATURES GENERALLY IN THE MID TO UPPER 70S. THE HIGHEST RAIN
CHANCES WILL BE FRIDAY WITH PRECIPITABLE WATERS BETWEEN 2.2 TO 2.5
INCHES PER THE LATEST NAM/GFS. HIGH TEMPERATURES FRIDAY WILL BE A
FEW DEGREES LOWER DUE TO THE INCREASE IN RAIN CHANCES AND CLOUD
COVER.
ANY OF THE HEAVIER OR SLOWER-MOVING SHOWERS AND THUNDERSTORMS TODAY
AND FRIDAY WILL HAVE THE POTENTIAL TO PRODUCE LOCALLY HEAVY RAINFALL
WITH NUISANCE FLOODING ON ROADS AND IN LOW-LYING AREAS...ESPECIALLY
THOSE WITH A HISTORY OF FLOODING.
LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...ACTIVE WEATHER
PATTERN REMAINS FOR THE LONG TERM PORTION OF THE FORECAST. WEAK
COLD FRONT PASSES THROUGH THE BRO CWFA FRIDAY NIGHT...WITH
INVERTED SURFACE TROUGHINESS FORMING AND PERSISTING ALONG THE
LOWER TEXAS COAST AFTERWARDS. SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS ARE FORECAST FOR FRIDAY NIGHT THROUGH SUNDAY...
WITH LOCALLY HEAVY RAINFALL POSSIBLE FRIDAY NIGHT AND SATURDAY
WITH DEEP TROPICAL MOISTURE IN PLACE. CONVECTION WILL BECOME MORE
ISOLATED SUNDAY NIGHT THROUGH THE END OF THE FORECAST AS THE FOCUS
OF THE ACTIVITY SHIFTS MORE OFFSHORE WITH WEAK LOW PRESSURE
POSSIBLY ATTEMPTING TO FORM OVER THE WESTERN GULF OF MEXICO.
TEMPERATURES WILL BE TEMPERED EARLY IN THE FORECAST PERIOD
COURTESY OF THE INCREASED CLOUDINESS AND OPPORTUNITIES FOR
RAINFALL...BUT SHOULD WARM UP TOWARDS THE MIDDLE AND END OF THE
FORECAST WITH LESSER CHANCES OF RAIN IN PLACE.
MARINE...NOW THROUGH FRIDAY...BUOY DATA AND OBSERVATION PLATFORMS
ALONG THE LOWER TEXAS COAST THIS MORNING INDICATE SOUTH WINDS BETWEEN
8 TO 13 KNOTS WITH SEA HEIGHTS NEAR 3 FEET ON THE GULF WATERS. A
WEAK PRESSURE GRADIENT ALONG THE LOWER TEXAS COAST WILL MAINTAIN
LIGHT TO MODERATE SOUTH TO SOUTHEAST WINDS AND LOW TO MODERATE
SEAS. HOWEVER...SMALL CRAFT WILL NEED TO EXERCISE CAUTION ON THE
LAGUNA MADRE THIS AFTERNOON DUE TO A SLIGHTLY STRONGER WINDS.
FRIDAY NIGHT THROUGH WEDNESDAY...LIGHT TO MODERATE WINDS AND LOW
TO MODERATE SEAS WILL PREVAIL ALONG THE LOWER TEXAS COAST THROUGH
EARLY NEXT WEEK AS A WEAK COLD FRONT PASSES THROUGH FRIDAY NIGHT
AND WEAK LOW PRESSURE PERSISTS AFTERWARDS. MARINE CONDITIONS NEAR
THE END OF THE FORECAST PERIOD ARE DEPENDENT ON THE DEVELOPMENT...
IF ANY...OF A WEAK AREA OF LOW PRESSURE OVER THE WESTERN GULF OF
MEXICO.
BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
$$
THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV
&&
.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV
64
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
1003 AM CDT THU SEP 10 2015
.DISCUSSION...NO CHANGES MADE TO THE MORNING FORECAST PACKAGE.
THERE IS ONGOING CONVECTION ACROSS THE VICTORIA CROSSROADS AREA
THAT IS QUICKLY MOVING TO THE OUT OF THE COUNTY. COULD SEE
ISOLATED AMOUNTS OF 2 TO 3 INCHES POSSIBLE WITH SOME OF THE
SHOWERS/STORMS TODAY WITH 12Z CRP SOUNDING REPORTING 2.24 INCHES.
LAPS ANALYSIS SHOWS AREAS TO THE SOUTH HAVE STABILIZED FROM
EARLIER RAINS...BUT SHOULD SEE THE AREA BECOME UNSTABLE AGAIN
WITH A BIT MORE HEATING. FARTHER SOUTH ACROSS THE SOUTHERN COASTAL
BEND AND EASTERN BRUSH COUNTRY...INSTABILITY HAS INCREASED WITH
NOTICEABLE CU FIELD DEVELOPING ON VISIBLE IMAGERY AND WILL EXPECT
MORE CONVECTIVE DEVELOPMENT ACROSS THIS AREA THROUGH THE LATE
MORNING AND EARLY AFTERNOON HOURS. COVERAGE SHOULD INCREASE ACROSS
THE EASTERN CWA THROUGH THE REST OF THE AFTERNOON HOURS...SLOWLY
PROGRESSING FARTHER WEST INTO THE LATE AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 630 AM CDT THU SEP 10 2015/
DISCUSSION...SEE AVIATION SECTION FOR 12Z TAFS.
AVIATION...PATCHY MVFR CEILINGS EXIST UNDERNEATH CIRRUS OVER THE
REGION...MAINLY NEAR THE COAST AND NORTHERN BRUSH COUNTRY. PATCHY
FOG CONTINUES FROM BEEVILLE TO VICTORIA WITH MVFR VSBYS THAT WILL
LINGER FOR A COUPLE OF MORE HOURS. SCATTERED SHOWERS/THUNDERSTORMS
FORMING IN CONVERGENCE ZONE ALONG THE COAST THIS MORNING WHILE AN
AREA OF SHOWERS PERSISTS NEAR COTULLA. MVFR CIGS WILL PERSIST FOR
THE COASTAL PLAINS THIS MORNING WITH AREAL SHOWERS PROVIDING MVFR
VSBYS. SCATTERED-NUMEROUS SHOWERS AND THUNDERSTORMS WILL BE OVER
THE REGION FROM LATE MORNING THRU THE AFTERNOON. WILL SHOW LOW END
MVFR VSBYS POSSIBLE WITHIN THE T-STORMS BUT IFR VSBYS WILL OCCUR
IN THE STRONGER DOWNPOURS ALONG WITH GUSTY WINDS. EXPECT THE
CONVECTION WILL DIMINISH WITH THE LOSS OF HEATING EARLY IN THE
EVENING. VFR CONDITIONS AFTER 02Z WITH MAINLY MID LEVEL CLOUDS
OVER SOUTH TEXAS THROUGH 06Z. ANOTHER UPPER LEVEL DISTURBANCE
WILL APPROACH THE REGION FROM THE NORTHWEST OVERNIGHT. SCATTERED
CONVECTION IS EXPECTED TO REDEVELOP AROUND 08Z FRIDAY PROVIDING
MVFR VSBYS/CIGS.
PREV DISCUSSION... /ISSUED 425 AM CDT THU SEP 10 2015/
SHORT TERM (TODAY THROUGH FRIDAY)...GOES SOUNDER IMAGE OF
PRECIPITABLE WATER SHOWS A VERY MOIST AIR MASS IN PLACE ACROSS
THE REGION WITH PWAT VALUES BETWEEN 2.3 AND 2.5 INCHES. WATER
VAPOR IMAGERY SHOWS THE TAIL END OF A SHORT WAVE TROUGH FROM
EAST TEXAS EXTENDING WEST INTO CENTRAL TEXAS THIS MORNING.
THIS SHORT WAVE TROUGH WILL MOVE SOUTHEAST TOWARD THE UPPER
TEXAS COAST TODAY. A MODEST UPPER LEVEL JET STREAK IS ROUNDING
THE UPPER RIDGE TO THE WEST AND NOSING DOWN INTO THE HILL
COUNTRY. SCATTERED CONVECTION HAS FORMED NORTH OF COTULLA
EARLY THIS MORNING NEAR THIS UPPER JET FEATURE. THE LATEST
TECH WRF...OOZ NSSL WRF AND 05Z HRRR SHOW THIS ACTIVITY WILL
DIMINISH LATER THIS MORNING WITH ADDITIONAL CONVECTION FORMING
NEAR LOW LEVEL CONVERGENCE ZONE ALONG THE COAST. THE NOSE OF
THE UPPER JET WILL BE OVER THE VICTORIA CROSSROADS TO THE
COASTAL BEND TODAY. SO KEPT LIKELY POPS IN THIS REGION FOR
TODAY WITH CHANCE POPS OVER THE BRUSH COUNTRY. CONVECTION MAY
LINGER OVER THE BRUSH COUNTRY THIS EVENING AS BOUNDARY
INTERACTIONS KEEP ACTIVITY GOING FOR A FEW HOURS AFTER LOSS
OF HEATING. THERE SHOULD BE A BRIEF LULL IN ACTIVITY LATE THIS
EVENING...BUT ANOTHER SHORT WAVE TROUGH WILL BE APPROACHING THE
AREA FROM THE NORTHWEST AFTER MIDNIGHT. MODELS SUGGEST SCATTERED
CONVECTION WILL FORM OVERNIGHT AHEAD OF THIS FEATURE. THE UPPER
LEVEL JET STREAK MOVES TOWARD SOUTHEAST TEXAS ON FRIDAY WITH
WEAKLY DIFLUENT UPPER FLOW OVER THE REGION. WITH DEEP MOISTURE
REMAINING OVER SOUTH TEXAS...LOOKS LIKE MOST OF THE AREA WILL HAVE
A GOOD CHANCE TO SEE ADDITIONAL RAINFALL FROM SCATTERED TO
NUMEROUS CONVECTION FRIDAY. WENT LIKELY POPS FOR ENTIRE AREA ON
FRIDAY WITH MAX TEMPERATURES IN THE UPPER 80S EAST TO LOWER 90S
WEST.
LONG TERM (FRIDAY NIGHT THROUGH WEDNESDAY)...MOISTURE FROM WEAK
SURFACE BOUNDARY WILL BE SINKING INTO DEEP SOUTH TEXAS AT THE
BEGINNING OF LONG TERM PERIOD. HAVE CHANCE TO LIKELY POPS REMAINING
FRIDAY NIGHT...THEN DECREASING ON SATURDAY. DRIER CONDITIONS ARE
EXPECTED FOR SUNDAY AS HIGH PRESSURE RIDGE BRIEFLY BUILDS ACROSS THE
REGION. EARLY NEXT WEEK MOISTURE RETURNS TO THE AREA AS A COASTAL
TROUGH DEVELOPS IN ALONG THE GULF COAST. MODELS DIFFER SIGNIFICANTLY
ON THE DETAILS OF THIS TROUGH...BUT BOTH GFS AND ECMWF INDICATE
INCREASING CHANCES FOR SHOWERS AND STORMS TUESDAY AND WEDNESDAY.
THERE IS SOME TREND TO KEEP THE MAJORITY OF THE RAINFALL IN THE
MARINE AREAS...BUT WILL HOLD ONTO CHANCE POPS IN THE COASTAL BEND
AND BRUSH COUNTRY TEMPERATURES SHOULD BE SLIGHTLY BELOW NORMAL OVER
THE WEEKEND AND INTO EARLY NEXT WEEK...THEN GRADUALLY WARM BACK TO
NEAR NORMAL BY WEDNESDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 92 77 89 74 88 / 60 40 60 50 40
VICTORIA 90 74 88 71 86 / 60 40 60 30 20
LAREDO 99 78 93 73 89 / 40 40 60 50 40
ALICE 94 75 91 72 89 / 60 40 60 50 40
ROCKPORT 90 78 88 74 87 / 60 50 60 50 40
COTULLA 95 75 91 72 91 / 50 40 60 30 20
KINGSVILLE 93 76 90 73 88 / 60 40 60 50 40
NAVY CORPUS 90 79 87 75 86 / 60 50 60 50 40
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
CB/85...SHORT TERM
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
630 AM CDT THU SEP 10 2015
.DISCUSSION...SEE AVIATION SECTION FOR 12Z TAFS.
&&
.AVIATION...PATCHY MVFR CEILINGS EXIST UNDERNEATH CIRRUS OVER THE
REGION...MAINLY NEAR THE COAST AND NORTHERN BRUSH COUNTRY. PATCHY
FOG CONTINUES FROM BEEVILLE TO VICTORIA WITH MVFR VSBYS THAT WILL
LINGER FOR A COUPLE OF MORE HOURS. SCATTERED SHOWERS/THUNDERSTORMS
FORMING IN CONVERGENCE ZONE ALONG THE COAST THIS MORNING WHILE AN
AREA OF SHOWERS PERSISTS NEAR COTULLA. MVFR CIGS WILL PERSIST FOR
THE COASTAL PLAINS THIS MORNING WITH AREAL SHOWERS PROVIDING MVFR
VSBYS. SCATTERED-NUMEROUS SHOWERS AND THUNDERSTORMS WILL BE OVER
THE REGION FROM LATE MORNING THRU THE AFTERNOON. WILL SHOW LOW END
MVFR VSBYS POSSIBLE WITHIN THE T-STORMS BUT IFR VSBYS WILL OCCUR
IN THE STRONGER DOWNPOURS ALONG WITH GUSTY WINDS. EXPECT THE
CONVECTION WILL DIMINISH WITH THE LOSS OF HEATING EARLY IN THE
EVENING. VFR CONDITIONS AFTER 02Z WITH MAINLY MID LEVEL CLOUDS
OVER SOUTH TEXAS THROUGH 06Z. ANOTHER UPPER LEVEL DISTURBANCE
WILL APPROACH THE REGION FROM THE NORTHWEST OVERNIGHT. SCATTERED
CONVECTION IS EXPECTED TO REDEVELOP AROUND 08Z FRIDAY PROVIDING
MVFR VSBYS/CIGS.
&&
.PREV DISCUSSION... /ISSUED 425 AM CDT THU SEP 10 2015/
SHORT TERM (TODAY THROUGH FRIDAY)...GOES SOUNDER IMAGE OF
PRECIPITABLE WATER SHOWS A VERY MOIST AIR MASS IN PLACE ACROSS
THE REGION WITH PWAT VALUES BETWEEN 2.3 AND 2.5 INCHES. WATER
VAPOR IMAGERY SHOWS THE TAIL END OF A SHORT WAVE TROUGH FROM
EAST TEXAS EXTENDING WEST INTO CENTRAL TEXAS THIS MORNING.
THIS SHORT WAVE TROUGH WILL MOVE SOUTHEAST TOWARD THE UPPER
TEXAS COAST TODAY. A MODEST UPPER LEVEL JET STREAK IS ROUNDING
THE UPPER RIDGE TO THE WEST AND NOSING DOWN INTO THE HILL
COUNTRY. SCATTERED CONVECTION HAS FORMED NORTH OF COTULLA
EARLY THIS MORNING NEAR THIS UPPER JET FEATURE. THE LATEST
TECH WRF...OOZ NSSL WRF AND 05Z HRRR SHOW THIS ACTIVITY WILL
DIMINISH LATER THIS MORNING WITH ADDITIONAL CONVECTION FORMING
NEAR LOW LEVEL CONVERGENCE ZONE ALONG THE COAST. THE NOSE OF
THE UPPER JET WILL BE OVER THE VICTORIA CROSSROADS TO THE
COASTAL BEND TODAY. SO KEPT LIKELY POPS IN THIS REGION FOR
TODAY WITH CHANCE POPS OVER THE BRUSH COUNTRY. CONVECTION MAY
LINGER OVER THE BRUSH COUNTRY THIS EVENING AS BOUNDARY
INTERACTIONS KEEP ACTIVITY GOING FOR A FEW HOURS AFTER LOSS
OF HEATING. THERE SHOULD BE A BRIEF LULL IN ACTIVITY LATE THIS
EVENING...BUT ANOTHER SHORT WAVE TROUGH WILL BE APPROACHING THE
AREA FROM THE NORTHWEST AFTER MIDNIGHT. MODELS SUGGEST SCATTERED
CONVECTION WILL FORM OVERNIGHT AHEAD OF THIS FEATURE. THE UPPER
LEVEL JET STREAK MOVES TOWARD SOUTHEAST TEXAS ON FRIDAY WITH
WEAKLY DIFLUENT UPPER FLOW OVER THE REGION. WITH DEEP MOISTURE
REMAINING OVER SOUTH TEXAS...LOOKS LIKE MOST OF THE AREA WILL HAVE
A GOOD CHANCE TO SEE ADDITIONAL RAINFALL FROM SCATTERED TO
NUMEROUS CONVECTION FRIDAY. WENT LIKELY POPS FOR ENTIRE AREA ON
FRIDAY WITH MAX TEMPERATURES IN THE UPPER 80S EAST TO LOWER 90S
WEST.
LONG TERM (FRIDAY NIGHT THROUGH WEDNESDAY)...MOISTURE FROM WEAK
SURFACE BOUNDARY WILL BE SINKING INTO DEEP SOUTH TEXAS AT THE
BEGINNING OF LONG TERM PERIOD. HAVE CHANCE TO LIKELY POPS REMAINING
FRIDAY NIGHT...THEN DECREASING ON SATURDAY. DRIER CONDITIONS ARE
EXPECTED FOR SUNDAY AS HIGH PRESSURE RIDGE BRIEFLY BUILDS ACROSS THE
REGION. EARLY NEXT WEEK MOISTURE RETURNS TO THE AREA AS A COASTAL
TROUGH DEVELOPS IN ALONG THE GULF COAST. MODELS DIFFER SIGNIFICANTLY
ON THE DETAILS OF THIS TROUGH...BUT BOTH GFS AND ECMWF INDICATE
INCREASING CHANCES FOR SHOWERS AND STORMS TUESDAY AND WEDNESDAY.
THERE IS SOME TREND TO KEEP THE MAJORITY OF THE RAINFALL IN THE
MARINE AREAS...BUT WILL HOLD ONTO CHANCE POPS IN THE COASTAL BEND
AND BRUSH COUNTRY TEMPERATURES SHOULD BE SLIGHTLY BELOW NORMAL OVER
THE WEEKEND AND INTO EARLY NEXT WEEK...THEN GRADUALLY WARM BACK TO
NEAR NORMAL BY WEDNESDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 92 77 89 74 88 / 60 40 60 50 40
VICTORIA 90 74 88 71 86 / 60 40 60 30 20
LAREDO 99 78 93 73 89 / 40 40 60 50 40
ALICE 94 75 91 72 89 / 60 40 60 50 40
ROCKPORT 90 78 88 74 87 / 60 50 60 50 40
COTULLA 95 75 91 72 91 / 50 40 60 30 20
KINGSVILLE 93 76 90 73 88 / 60 40 60 50 40
NAVY CORPUS 90 79 87 75 86 / 60 50 60 50 40
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
TMT/89...AVIATION
AREA FORECAST DISCUSSION...UPDATED
NWS BROWNSVILLE TX
556 AM CDT THU SEP 10 2015
.DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.
&&
.AVIATION...LIGHT SOUTHEAST WINDS WITH A FEW PASSING CLOUDS
PREVAIL OVER DEEP SOUTH TEXAS THIS MORNING. SOME PATCHY LIGHT FOG
AND LOW CLOUD DECKS HAVE BEEN OBSERVED ACROSS THE REGION IN THE
PAST COUPLE OF HOURS. BRIEF MVFR CONDITIONS WILL BE POSSIBLE JUST
AFTER SUNRISE. OTHERWISE...VFR CONDITIONS EXPECTED THROUGH THIS
LATE EVENING. WILL KEEP THE MENTION OF VCSH AT ALL TAF SITES AS
ISOLATED SEA BREEZE ACTIVITY IS POSSIBLE LATER TODAY. LIGHT
SOUTHEAST WINDS WILL BECOME MODERATE LATER THIS MORNING WITH GUSTS
AROUND 20 KNOTS IN THE AFTERNOON. WINDS WILL GRADUALLY WEAKEN THIS
EVENING WITH INCREASING LOW CLOUDS LATE TONIGHT.
&&
.PREV DISCUSSION... /ISSUED 422 AM CDT THU SEP 10 2015/
SHORT TERM /NOW THROUGH FRIDAY/...LATEST WATER VAPOR SATELLITE
IMAGERY SHOWS A 500MB RIDGE CENTERED OVER WEST TEXAS INTO NORTHERN
MEXICO AND OVER SOUTH FLORIDA WITH 500MB WEAKNESS OVER THE WESTERN
GULF OF MEXICO. BROWNSVILLE RADAR SHOWS ISOLATED ACTIVITY ACROSS THE
LOWER TEXAS GULF WATERS THIS MORNING. THE LATEST HRRR SUGGESTS
CONVECTION WILL INCREASE ACROSS THE GULF WATERS THROUGH SUNRISE. BRO
SOUNDING FROM WEDNESDAY EVENING INDICATES PRECIPITABLE WATER VALUES
OF 1.87 INCHES. EXCEPT FOR SOME PASSING HIGH CLOUDS...MOSTLY CLEAR
SKIES AND LIGHT WINDS PREVAIL ACROSS DEEP SOUTH TEXAS EARLY THIS
MORNING. A LITTLE GROUND FOG MAY DEVELOP AROUND SUNRISE BEFORE
QUICKLY DISSIPATING. NOTE...THE SURFACE OBSERVATION FROM EDINBURG IS
NOT REPRESENTATIVE TO CURRENT WEATHER CONDITIONS.
THE MAIN FORECAST ISSUE WILL BE THE RAIN CHANCES ACROSS DEEP SOUTH
TEXAS THROUGH THE FORECAST PERIOD. DEEP TROPICAL MOISTURE
/PRECIPITABLE WATER VALUES IN EXCESS OF 2 INCHES/ COMBINED WITH DAY
TIME HEATING WILL SUPPORT ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS TODAY. HIGH TEMPERATURES TODAY WILL RANGE FROM THE
LOWER 90S NEAR THE COAST TO THE UPPER 90S ACROSS THE UPPER VALLEY.
RAIN CHANCES MAY LINGER ACROSS THE NORTHERN RANCHLANDS TONIGHT AS
THE GFS SUGGESTS. OTHERWISE...MOSTLY CLOUDY SKIES WITH LOW
TEMPERATURES GENERALLY IN THE MID TO UPPER 70S. THE HIGHEST RAIN
CHANCES WILL BE FRIDAY WITH PRECIPITABLE WATERS BETWEEN 2.2 TO 2.5
INCHES PER THE LATEST NAM/GFS. HIGH TEMPERATURES FRIDAY WILL BE A
FEW DEGREES LOWER DUE TO THE INCREASE IN RAIN CHANCES AND CLOUD
COVER.
ANY OF THE HEAVIER OR SLOWER-MOVING SHOWERS AND THUNDERSTORMS TODAY
AND FRIDAY WILL HAVE THE POTENTIAL TO PRODUCE LOCALLY HEAVY RAINFALL
WITH NUISANCE FLOODING ON ROADS AND IN LOW-LYING AREAS...ESPECIALLY
THOSE WITH A HISTORY OF FLOODING.
LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...ACTIVE WEATHER
PATTERN REMAINS FOR THE LONG TERM PORTION OF THE FORECAST. WEAK
COLD FRONT PASSES THROUGH THE BRO CWFA FRIDAY NIGHT...WITH
INVERTED SURFACE TROUGHINESS FORMING AND PERSISTING ALONG THE
LOWER TEXAS COAST AFTERWARDS. SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS ARE FORECAST FOR FRIDAY NIGHT THROUGH SUNDAY...
WITH LOCALLY HEAVY RAINFALL POSSIBLE FRIDAY NIGHT AND SATURDAY
WITH DEEP TROPICAL MOISTURE IN PLACE. CONVECTION WILL BECOME MORE
ISOLATED SUNDAY NIGHT THROUGH THE END OF THE FORECAST AS THE FOCUS
OF THE ACTIVITY SHIFTS MORE OFFSHORE WITH WEAK LOW PRESSURE
POSSIBLY ATTEMPTING TO FORM OVER THE WESTERN GULF OF MEXICO.
TEMPERATURES WILL BE TEMPERED EARLY IN THE FORECAST PERIOD
COURTESY OF THE INCREASED CLOUDINESS AND OPPORTUNITIES FOR
RAINFALL...BUT SHOULD WARM UP TOWARDS THE MIDDLE AND END OF THE
FORECAST WITH LESSER CHANCES OF RAIN IN PLACE.
MARINE...NOW THROUGH FRIDAY...BUOY DATA AND OBSERVATION PLATFORMS
ALONG THE LOWER TEXAS COAST THIS MORNING INDICATE SOUTH WINDS BETWEEN
8 TO 13 KNOTS WITH SEA HEIGHTS NEAR 3 FEET ON THE GULF WATERS. A
WEAK PRESSURE GRADIENT ALONG THE LOWER TEXAS COAST WILL MAINTAIN
LIGHT TO MODERATE SOUTH TO SOUTHEAST WINDS AND LOW TO MODERATE
SEAS. HOWEVER...SMALL CRAFT WILL NEED TO EXERCISE CAUTION ON THE
LAGUNA MADRE THIS AFTERNOON DUE TO A SLIGHTLY STRONGER WINDS.
FRIDAY NIGHT THROUGH WEDNESDAY...LIGHT TO MODERATE WINDS AND LOW
TO MODERATE SEAS WILL PREVAIL ALONG THE LOWER TEXAS COAST THROUGH
EARLY NEXT WEEK AS A WEAK COLD FRONT PASSES THROUGH FRIDAY NIGHT
AND WEAK LOW PRESSURE PERSISTS AFTERWARDS. MARINE CONDITIONS NEAR
THE END OF THE FORECAST PERIOD ARE DEPENDENT ON THE DEVELOPMENT...
IF ANY...OF A WEAK AREA OF LOW PRESSURE OVER THE WESTERN GULF OF
MEXICO.
&&
.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV
63
AREA FORECAST DISCUSSION
NWS CORPUS CHRISTI TX
425 AM CDT THU SEP 10 2015
.SHORT TERM (TODAY THROUGH FRIDAY)...GOES SOUNDER IMAGE OF
PRECIPITABLE WATER SHOWS A VERY MOIST AIR MASS IN PLACE ACROSS
THE REGION WITH PWAT VALUES BETWEEN 2.3 AND 2.5 INCHES. WATER
VAPOR IMAGERY SHOWS THE TAIL END OF A SHORT WAVE TROUGH FROM
EAST TEXAS EXTENDING WEST INTO CENTRAL TEXAS THIS MORNING.
THIS SHORT WAVE TROUGH WILL MOVE SOUTHEAST TOWARD THE UPPER
TEXAS COAST TODAY. A MODEST UPPER LEVEL JET STREAK IS ROUNDING
THE UPPER RIDGE TO THE WEST AND NOSING DOWN INTO THE HILL
COUNTRY. SCATTERED CONVECTION HAS FORMED NORTH OF COTULLA
EARLY THIS MORNING NEAR THIS UPPER JET FEATURE. THE LATEST
TECH WRF...OOZ NSSL WRF AND 05Z HRRR SHOW THIS ACTIVITY WILL
DIMINISH LATER THIS MORNING WITH ADDITIONAL CONVECTION FORMING
NEAR LOW LEVEL CONVERGENCE ZONE ALONG THE COAST. THE NOSE OF
THE UPPER JET WILL BE OVER THE VICTORIA CROSSROADS TO THE
COASTAL BEND TODAY. SO KEPT LIKELY POPS IN THIS REGION FOR
TODAY WITH CHANCE POPS OVER THE BRUSH COUNTRY. CONVECTION MAY
LINGER OVER THE BRUSH COUNTRY THIS EVENING AS BOUNDARY
INTERACTIONS KEEP ACTIVITY GOING FOR A FEW HOURS AFTER LOSS
OF HEATING. THERE SHOULD BE A BRIEF LULL IN ACTIVITY LATE THIS
EVENING...BUT ANOTHER SHORT WAVE TROUGH WILL BE APPROACHING THE
AREA FROM THE NORTHWEST AFTER MIDNIGHT. MODELS SUGGEST SCATTERED
CONVECTION WILL FORM OVERNIGHT AHEAD OF THIS FEATURE. THE UPPER
LEVEL JET STREAK MOVES TOWARD SOUTHEAST TEXAS ON FRIDAY WITH
WEAKLY DIFLUENT UPPER FLOW OVER THE REGION. WITH DEEP MOISTURE
REMAINING OVER SOUTH TEXAS...LOOKS LIKE MOST OF THE AREA WILL HAVE
A GOOD CHANCE TO SEE ADDITIONAL RAINFALL FROM SCATTERED TO
NUMEROUS CONVECTION FRIDAY. WENT LIKELY POPS FOR ENTIRE AREA ON
FRIDAY WITH MAX TEMPERATURES IN THE UPPER 80S EAST TO LOWER 90S
WEST.
&&
.LONG TERM (FRIDAY NIGHT THROUGH WEDNESDAY)...MOISTURE FROM WEAK
SURFACE BOUNDARY WILL BE SINKING INTO DEEP SOUTH TEXAS AT THE
BEGINNING OF LONG TERM PERIOD. HAVE CHANCE TO LIKELY POPS REMAINING
FRIDAY NIGHT...THEN DECREASING ON SATURDAY. DRIER CONDITIONS ARE
EXPECTED FOR SUNDAY AS HIGH PRESSURE RIDGE BRIEFLY BUILDS ACROSS THE
REGION. EARLY NEXT WEEK MOISTURE RETURNS TO THE AREA AS A COASTAL
TROUGH DEVELOPS IN ALONG THE GULF COAST. MODELS DIFFER SIGNIFICANTLY
ON THE DETAILS OF THIS TROUGH...BUT BOTH GFS AND ECMWF INDICATE
INCREASING CHANCES FOR SHOWERS AND STORMS TUESDAY AND WEDNESDAY.
THERE IS SOME TREND TO KEEP THE MAJORITY OF THE RAINFALL IN THE
MARINE AREAS...BUT WILL HOLD ONTO CHANCE POPS IN THE COASTAL BEND
AND BRUSH COUNTRY TEMPERATURES SHOULD BE SLIGHTLY BELOW NORMAL OVER
THE WEEKEND AND INTO EARLY NEXT WEEK...THEN GRADUALLY WARM BACK TO
NEAR NORMAL BY WEDNESDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 92 77 89 74 88 / 60 40 60 50 40
VICTORIA 90 74 88 71 86 / 60 40 60 30 20
LAREDO 99 78 93 73 89 / 40 40 60 50 40
ALICE 94 75 91 72 89 / 60 40 60 50 40
ROCKPORT 90 78 88 74 87 / 60 50 60 50 40
COTULLA 95 75 91 72 91 / 50 40 60 30 20
KINGSVILLE 93 76 90 73 88 / 60 40 60 50 40
NAVY CORPUS 90 79 87 75 86 / 60 50 60 50 40
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
TMT/89...SHORT TERM
PZ/83...LONG TERM
AREA FORECAST DISCUSSION
NWS BROWNSVILLE TX
422 AM CDT THU SEP 10 2015
.SHORT TERM /NOW THROUGH FRIDAY/...LATEST WATER VAPOR SATELLITE
IMAGERY SHOWS A 500MB RIDGE CENTERED OVER WEST TEXAS INTO NORTHERN
MEXICO AND OVER SOUTH FLORIDA WITH 500MB WEAKNESS OVER THE WESTERN
GULF OF MEXICO. BROWNSVILLE RADAR SHOWS ISOLATED ACTIVITY ACROSS THE
LOWER TEXAS GULF WATERS THIS MORNING. THE LATEST HRRR SUGGESTS
CONVECTION WILL INCREASE ACROSS THE GULF WATERS THROUGH SUNRISE. BRO
SOUNDING FROM WEDNESDAY EVENING INDICATES PRECIPITABLE WATER VALUES
OF 1.87 INCHES. EXCEPT FOR SOME PASSING HIGH CLOUDS...MOSTLY CLEAR
SKIES AND LIGHT WINDS PREVAIL ACROSS DEEP SOUTH TEXAS EARLY THIS
MORNING. A LITTLE GROUND FOG MAY DEVELOP AROUND SUNRISE BEFORE
QUICKLY DISSIPATING. NOTE...THE SURFACE OBSERVATION FROM EDINBURG IS
NOT REPRESENTATIVE TO CURRENT WEATHER CONDITIONS.
THE MAIN FORECAST ISSUE WILL BE THE RAIN CHANCES ACROSS DEEP SOUTH
TEXAS THROUGH THE FORECAST PERIOD. DEEP TROPICAL MOISTURE
/PRECIPITABLE WATER VALUES IN EXCESS OF 2 INCHES/ COMBINED WITH DAY
TIME HEATING WILL SUPPORT ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS TODAY. HIGH TEMPERATURES TODAY WILL RANGE FROM THE
LOWER 90S NEAR THE COAST TO THE UPPER 90S ACROSS THE UPPER VALLEY.
RAIN CHANCES MAY LINGER ACROSS THE NORTHERN RANCHLANDS TONIGHT AS
THE GFS SUGGESTS. OTHERWISE...MOSTLY CLOUDY SKIES WITH LOW
TEMPERATURES GENERALLY IN THE MID TO UPPER 70S. THE HIGHEST RAIN
CHANCES WILL BE FRIDAY WITH PRECIPITABLE WATERS BETWEEN 2.2 TO 2.5
INCHES PER THE LATEST NAM/GFS. HIGH TEMPERATURES FRIDAY WILL BE A
FEW DEGREES LOWER DUE TO THE INCREASE IN RAIN CHANCES AND CLOUD
COVER.
ANY OF THE HEAVIER OR SLOWER-MOVING SHOWERS AND THUNDERSTORMS TODAY
AND FRIDAY WILL HAVE THE POTENTIAL TO PRODUCE LOCALLY HEAVY RAINFALL
WITH NUISANCE FLOODING ON ROADS AND IN LOW-LYING AREAS...ESPECIALLY
THOSE WITH A HISTORY OF FLOODING.
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...ACTIVE WEATHER
PATTERN REMAINS FOR THE LONG TERM PORTION OF THE FORECAST. WEAK
COLD FRONT PASSES THROUGH THE BRO CWFA FRIDAY NIGHT...WITH
INVERTED SURFACE TROUGHINESS FORMING AND PERSISTING ALONG THE
LOWER TEXAS COAST AFTERWARDS. SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS ARE FORECAST FOR FRIDAY NIGHT THROUGH SUNDAY...
WITH LOCALLY HEAVY RAINFALL POSSIBLE FRIDAY NIGHT AND SATURDAY
WITH DEEP TROPICAL MOISTURE IN PLACE. CONVECTION WILL BECOME MORE
ISOLATED SUNDAY NIGHT THROUGH THE END OF THE FORECAST AS THE FOCUS
OF THE ACTIVITY SHIFTS MORE OFFSHORE WITH WEAK LOW PRESSURE
POSSIBLY ATTEMPTING TO FORM OVER THE WESTERN GULF OF MEXICO.
TEMPERATURES WILL BE TEMPERED EARLY IN THE FORECAST PERIOD
COURTESY OF THE INCREASED CLOUDINESS AND OPPORTUNITIES FOR
RAINFALL...BUT SHOULD WARM UP TOWARDS THE MIDDLE AND END OF THE
FORECAST WITH LESSER CHANCES OF RAIN IN PLACE.
&&
.MARINE...NOW THROUGH FRIDAY...BUOY DATA AND OBSERVATION PLATFORMS
ALONG THE LOWER TEXAS COAST THIS MORNING INDICATE SOUTH WINDS BETWEEN
8 TO 13 KNOTS WITH SEA HEIGHTS NEAR 3 FEET ON THE GULF WATERS. A
WEAK PRESSURE GRADIENT ALONG THE LOWER TEXAS COAST WILL MAINTAIN
LIGHT TO MODERATE SOUTH TO SOUTHEAST WINDS AND LOW TO MODERATE
SEAS. HOWEVER...SMALL CRAFT WILL NEED TO EXERCISE CAUTION ON THE
LAGUNA MADRE THIS AFTERNOON DUE TO A SLIGHTLY STRONGER WINDS.
FRIDAY NIGHT THROUGH WEDNESDAY...LIGHT TO MODERATE WINDS AND LOW
TO MODERATE SEAS WILL PREVAIL ALONG THE LOWER TEXAS COAST THROUGH
EARLY NEXT WEEK AS A WEAK COLD FRONT PASSES THROUGH FRIDAY NIGHT
AND WEAK LOW PRESSURE PERSISTS AFTERWARDS. MARINE CONDITIONS NEAR
THE END OF THE FORECAST PERIOD ARE DEPENDENT ON THE DEVELOPMENT...
IF ANY...OF A WEAK AREA OF LOW PRESSURE OVER THE WESTERN GULF OF
MEXICO.
&&
.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL 92 80 91 75 / 20 20 40 60
BROWNSVILLE 93 79 91 74 / 20 20 40 60
HARLINGEN 95 78 93 72 / 30 20 50 60
MCALLEN 97 80 94 76 / 20 10 40 60
RIO GRANDE CITY 99 79 95 73 / 30 20 50 60
SOUTH PADRE ISLAND 87 82 85 76 / 20 20 40 60
&&
.BRO WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV
SHORT TERM...CACERES-63
LONG TERM...TOMASELLI-66
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
853 PM CDT FRI SEP 11 2015
.UPDATE...
RADAR SHOWS A DIMINISHING TREND TO THE ISOLATED LIGHT SHOWERS
MOVING SOUTH FROM CENTRAL WI ON THE LEADING EDGE OF THE 850 MB AND
700 MB COLD POOLS AND IN A REGION OF WEAK CVA WITH A SHORT WAVE
DROPPING SOUTH ALONG THE WI/MN BORDER. HRRR AND RAP SHOW THESE
ISOLATED LIGHT SHOWERS CONTINUING TO DIMINISH OVER THE NEXT FEW
HOURS AS LAYER Q-VECTOR CONVERGENCE WEAKENS WITH COLD AIR
ADVECTION DOMINATING THE VORTICITY ADVECTION...WHICH WILL BE
STRONGER TO THE WEST OF THE CWA. A FEW SPRINKLES WILL BE POSSIBLE.
AN EXCEPTION WILL BE NEAR LAKE MICHIGAN AS DELTA T/S FALL TO NEAR
18C AS COLDER 850 MB TEMPS SPREAD OVER THE WARMER LAKE WATERS.
MOST OF THE HI-RES RAPID UPDATE MODELS ARE KEEPING THE CONVERGENCE
ZONE...AND THUS ANY LIGHT SHOWERS...MAINLY OVER THE LAKE BUT THE
HRRR AND RAP ARE TRYING TO SHOW A BIT MORE ONSHORE FLOW AFTER 08Z AS
THE SURFACE HIGH BUILDS IN THAT PUSHES THE CONVERGENCE ZONE WEST
TOWARD OUR SHORE SO WILL KEEP THE SLIGHT CHANCE/CHANCE POPS ALONG
THE LAKE.
DIURNAL CU HAS DISSIPATED BUT STILL SEEING A FAIRLY WIDESPREAD
AREA OF COLD ADVECTION STRATOCUMULUS WITH THE POCKET OF COLDEST
850-700 MB AIR THAT WILL MOVE THROUGH SOUTHERN WISCONSIN
OVERNIGHT.
&&
.AVIATION/06Z TAFS/...
RADAR SHOWS A DIMINISHING TREND TO THE ISOLATED LIGHT SHOWERS
MOVING SOUTH FROM CENTRAL WI ON THE LEADING EDGE OF THE 850 MB AND
700 MB COLD POOLS SO DO NOT EXPECT ANYTHING MORE THAN SPRINKLES AT
TAF SITES IF THEY SHOULD SURVIVE THAT LONG.
AN EXCEPTION WILL BE NEAR LAKE MICHIGAN AS COLDER 850 MB TEMPS
SPREAD OVER THE WARMER LAKE WATERS. MOST OF THE HI-RES RAPID
UPDATE MODELS ARE KEEPING THE CONVERGENCE ZONE...AND THUS ANY
LIGHT SHOWERS...MAINLY OVER THE LAKE BUT THE HRRR AND RAP ARE
TRYING TO SHOW A BIT MORE ONSHORE FLOW AFTER 08Z AS THE SURFACE
HIGH BUILDS IN THAT PUSHES THE CONVERGENCE ZONE WEST
TOWARD OUR SHORE SO WILL KEEP THE SLIGHT CHANCE/CHANCE POPS ALONG
THE LAKE. ANY SHOWERS COULD ALSO BRING IN SOME MVFR CIGS.
WILL KEEP AN EYE ON COLD ADVECTION STRATOCUMULUS DECK THAT WILL
MAKE IT ACROSS SOUTHERN WISCONSIN OVERNIGHT...BUT IT IS EXPECTED
TO REMAIN AT VFR LEVELS.
THOUGH MID-LEVEL LAPSE RATES MODERATE AS COLD POCKETS MOVE SOUTH
OF AREA SATURDAY...STEEP LOW-LEVEL LAPSE RATES WILL PRODUCE AT
LEAST SCATTERED DIURNAL CU IN THE 3500-4K FT RANGE...WITH THE 18Z
NAM INDICATING SOME BROKEN VFR CUMULUS IN THE EAST. WILL MAKE
FINAL DECISION ON AMOUNT AND LEVEL OF SKY COVER AFTER GETTING A
LOOK AT 00Z DATA....BUT EVEN BROKEN CLOUD DECK EXPECTED TO BE AT
VFR LEVELS.
&&
.MARINE...
NORTH-NORTHEAST WIND GUSTS HAVE LOWERED TO BELOW CRITERIA IN THE
NORTHERN MARINE ZONES BUT WAVES WILL CONTINUE TO BE HIGH INTO
SATURDAY MORNING WITH THE PERSISTENT LONG FETCH. STRONG LAPSE
RATES AS THE POOL OF COLDEST AIR BETWEEN 4K AND 9K FEET MOVES OVER
THE WARM WATERS OF THE LAKE WILL KEEP SCATTERED SHOWERS IN THE
FORECAST...WITH CONDITIONS STILL FAVORABLE FOR WATERSPOUTS
OVERNIGHT...DIMINISHING AS THE COLD POCKET MOVES TO THE SOUTH
SATURDAY.
&&
.BEACHES...
WINDS AND WAVES HAVE LOWERED ENOUGH TO END THE BEACH HAZARD FOR
THE BEACHES OF SHEBOYGAN AND OZAUKEE COUNTIES BUT THERE WILL STILL BE
A MODERATE SWIM RISK AT THOSE LOCATIONS INTO SATURDAY AFTERNOON.
NO CHANGE TO THE BEACH HAZARD THAT RUNS UNTIL 4 PM SATURDAY FOR
THE BEACHES FROM MILWAUKEE COUNTY SOUTH TO THE ILLINOIS BORDER.
&&
.PREV DISCUSSION... /ISSUED 257 PM CDT FRI SEP 11 2015/
TONIGHT...FORECAST CONFIDENCE IS MEDIUM.
A LARGE MID LEVEL TROUGH WILL CONTINUE TO DIG/DEEPEN ACROSS THE
WESTERN GREAT LAKES TONIGHT. A COMPACT SHORTWAVE WILL ROTATE INTO
THE BASE OF THE TROF...TRACKING FROM EASTERN MN...SOUTH TO ERN IOWA
BY 12Z SATURDAY MORNING. THIS IS ACCOMPANIED BY COLD AIR ADVECTION
DOWN BELOW...THUS THE Q-VECTOR RESPONSE AND DEEPER OMEGA FIELDS ARE
PRETTY WEAK. A LOT OF THE CLOUDS ACROSS SOUTHERN WISCONSIN ARE
DIURNAL IN NATURE...BUT THE CLOUDS ACROSS THE NORTH/CENTRAL AREAS
ARE MORE SOLID AND ASSOCIATED WITH THE COLD AIR ADVECTION AND
THERMAL TROF. THOSE CLOUDS TO THE NORTH SHOULD GRADUALLY SPREAD
ACROSS THE AREA THIS EVENING. WE SHOULD SEE LAKE EFFECT SHOWERS
INCREASE OVER LAKE MICHIGAN AS THE DELTA T CLIMBS TO 16-18C.
BUT...THE MEAN FLOW SHOULD KEEP IT RIGHT ALONG THE
SHORE...IMPACTING MAINLY THE AREAS FROM MILWAUKEE SOUTH THROUGH
KENOSHA. IT/S POSSIBLE THEY WILL STAY OFF SHORE ENTIRELY.
SATURDAY...FORECAST CONFIDENCE IS HIGH.
THE 850MB THERMAL TROF WILL BE CENTERED OVER THE AREA IN THE
MORNING...DRIFTING OFF TO THE EAST LATER IN THE DAY. WE COULD SEE
SOME LAKE EFFECT SHOWERS IN THE FAR SOUTHEAST STILL...BUT THESE WILL
MOVE OFF BY AFTERNOON. CLOUDS MAY GENERALLY CLEAR OUT AWAY FROM THE
LAKE IN THE MORNING...BUT WITH THE THERMAL TROF OVERHEAD...WE SHOULD
SEE A RETURN OF DIURNAL CU IN THE AFTERNOON. JUST NOT SURE ABOUT THE
PERCENTAGE OF COVERAGE ATTM. WE COULD SEE DEWPOINTS MIX OUT AND
KEEP THE CU DECK SCT. HIGHS WILL STAY DOWN IN THE 60S.
SATURDAY NIGHT THROUGH TUESDAY...FORECAST CONFIDENCE...HIGH
SURFACE HIGH PRESSURE CENTERED JUST TO THE SOUTHWEST OF WISCONSIN
SATURDAY NIGHT WILL BUILD IN STRENGTH AND SLIDE EASTWARD SUNDAY
AND MONDAY...REMAINING IN PLACE OVER THE EASTERN UNITED STATES ON
TUESDAY. THIS SETUP SHOULD RESULT IN DRY WEATHER ACROSS SOUTHERN
WISCONSIN THROUGH THIS PERIOD.
SOUTHERLY WINDS WILL DEVELOP AS THE HIGH PUSHES TO THE
EAST...WHICH WILL RESULT IN A WARMING TREND INTO THE FIRST PART OF
NEXT WEEK. EXPECT HIGHS TO GET BACK TO AROUND 80 BY
TUESDAY...MAYBE EVEN A COUPLE DEGREES WARMER GIVEN SOME OF THE
MODEL 925 MB TEMPS.
WEDNESDAY THROUGH FRIDAY...FORECAST CONFIDENCE...MEDIUM
A TROUGH OF LOW PRESSURE AND ASSOCIATED COLD FRONT WILL APPROACH
THE AREA WEDNESDAY. STILL LOOKS LIKE THE SYSTEM WILL REMAIN FAR
ENOUGH WEST FOR DRY WEATHER DURING THE DAYTIME HOURS. CUT BACK ON
POPS WEDNESDAY NIGHT...AS THERE HAS BEEN AN OVERALL SLOWING TREND
IN THE MODELS. HAVE HIGHER POPS FOR SHOWERS/STORMS
THURSDAY/THURSDAY NIGHT AS THE FRONT SLOWLY MOVES THROUGH THE
REGION. WENT WITH SOME POPS FRIDAY TOO...AS THE ECMWF BRINGS A
QUICK MOVING SHORTWAVE THROUGH ON THE HEELS OF THE DEPARTING
PREVIOUS SYSTEM. NOT HIGH CONFIDENCE IN THESE POPS THOUGH...AS THE
GFS IS DRY FOR FRIDAY.
WITH INCREASING CONFIDENCE THAT WEDNESDAY WILL BE DRY...BUMPED
HIGH TEMPS UP TO WARMER THAN THE BULK OF MODELS. FEEL MODELS ARE
ON THE COOL SIDE GIVEN 925 MB TEMPS AROUND 23C. THURSDAY LOOKS
WARMER NOW TOO...WITH THE COLD FRONT NOT PROGGED TO MOVE THROUGH
UNTIL THURSDAY NIGHT. SHOULD THEN BE COOLER FRIDAY BEHIND THE
FRONT.
AVIATION/00Z TAFS/...
LOOKS LIKE CIGS WILL STAY VFR THROUGH THE TAF PERIOD. THE EXCEPTION
MIGHT BE FOR KMKE AND KENW LATER TONIGHT. THERE IS A PERIOD WHEN
SOME LAKE EFFECT CLOUDS AND POSSIBLE SHOWERS COULD TAKE CIGS DOWN TO
MVFR LEVELS FOR A FEW HOURS FROM ABOUT 08-12Z SAT. WINDS WILL
GRADUALLY DIMINISH TOWARD SUNSET THIS EVENING. BUT DUE TO KMKE/S
PROXIMITY TO LAKE MICHIGAN...WINDS THERE MAY STAY A BIT ELEVATED
WITH A FEW GUSTS TO 18KTS AT TIMES.
MARINE...
LAKE EFFECT SHOWERS WILL INCREASE OVER THE LAKE MICHIGAN WATERS
TONIGHT...MAINLY SOUTH OF PORT WASHINGTON. CONDITIONS REMAIN
FAVORABLE FOR WATERSPOUTS OVERNIGHT. THE SMALL CRAFT ADVISORY WILL
CONTINUE THROUGH THE NIGHT FOR THE ENTIRE NEARSHORE AREA...THEN FROM
MILWAUKEE SOUTH TO WINTHROP HARBOR THROUGH MID AFTERNOON ON SATURDAY
DUE TO PERSISTENT HIGH WAVES.
BEACHES...
WILL LET THE BEACH HAZARDS STATEMENT EXPIRE AT 00Z FOR OZAUKEE
COUNTY NORTH TO SHEBOYGAN...BUT WILL STRETCH IT THROUGH MID
AFTERNOON ON SATURDAY FOR MILWAUKEE/RACINE/KENOSHA COUNTIES. WINDS
AND WAVES REMAIN ELEVATED ACROSS THOSE COUNTIES INTO SATURDAY.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...BEACH HAZARDS STATEMENT THROUGH SATURDAY AFTERNOON FOR WIZ066-
071-072.
LM...SMALL CRAFT ADVISORY UNTIL 4 PM CDT SATURDAY FOR LMZ645-646.
SMALL CRAFT ADVISORY UNTIL 7 AM CDT SATURDAY FOR LMZ643-644.
&&
$$
UPDATE...REM
TONIGHT/SATURDAY AND AVIATION/MARINE...DAVIS
SATURDAY NIGHT THROUGH FRIDAY...DDV
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE
.SHORT TERM...TONIGHT AND FRIDAY
ISSUED AT 243 PM CDT THU SEP 10 2015
THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A COLD
FRONT STRETCHING FROM ABOUT IRON MOUNTAIN TO WAUSAU EARLY THIS
AFTERNOON. SHOWERS AND STORMS HAVE DEVELOPED ALONG IT OVER THE
UPPER PENINSULA...BUT ONLY A FEW BLIPS SHOWING UP ON RADAR OVER
NORTHERN WI SO FAR. SB CAPE HAS BEEN BUILDING AHEAD OF THE FRONT
AND THE HRRR/ARW CONTINUE TO DEVELOP SCT SHOWERS LATER THIS
AFTERNOON. ALTHOUGH BROUGHT DOWN PRECIP CHANCES SLIGHTLY THIS
AFTERNOON...DATA DOES NOT SUPPORT DROPPING THEM ENTIRELY. WILL KEEP
A SCATTERED MENTION MID-AFTERNOON INTO THE EARLY EVENING. BEHIND
THE FRONT...AN UPPER TROUGH IS DIGGING SOUTHWARD OVER ONTARIO AND
MINNESOTA...BRINGING WIDESPREAD CLOUDS AND SHOWERS WITH IT.
FORECAST CONCERNS INCLUDE PRECIP AND CLOUDS TRENDS.
TONIGHT...THE COLD FRONT WILL STALL OVER NORTHEAST WI FOR A PERIOD
THIS EVENING AS IT WAITS FOR A SHORTWAVE OVER NORTHERN MINNESOTA TO
ARRIVE. THEN THE SHORTWAVE WILL GIVE THE FRONT A PUSH TO THE SOUTH
LATE OVERNIGHT. DUE TO THE SLOW DEPARTURE OF THE FRONT...WILL KEEP
A SMALL CHANCE OF A SHOWER OVER NE WI UNTIL LATE TONIGHT.
OTHERWISE...THE SHORTWAVE WILL BRING AN INFLUX OF LOW STRATUS
SOUTHEAST FROM NORTHERN MINNESOTA AND WESTERN ONTARIO. 850MB TEMPS
WILL FALL TO AROUND +1C OVER WESTERN LAKE SUPERIOR...WHICH WILL
CREATE DELTA T/S OF AROUND 14C...SUFFICIENT OF LAKE EFFECT RAIN
SHOWERS TO DEVELOP. THEREFORE...AFTER A DRY START TO THE
EVENING....NORTH-CENTRAL WISCONSIN SHOULD SEE CLOUDS INCREASE AND
SHOWERS MOVE IN AFTER MIDNIGHT. LOWS TO FALL INTO THE MID 40S NORTH
TO LOW 50S SOUTH.
FRIDAY...THE UPPER TROUGH WILL MOVE OVERHEAD...BRINGING A COOL AND
CLOUDY AIRMASS WITH IT. THE MAIN VORT MAX WILL BE EXITING NORTHEAST
WISCONSIN AROUND MIDDAY...WHICH IS PERHAPS A REASON WHY MODELS ARE
UNENTHUSIASTIC ABOUT PRECIP CHANCES. HOWEVER...MODELS PROJECT A
NEARLY SATURATED LAYER UP TO ABOUT 700MB WITH STEEP LOW LEVEL LAPSE
RATES IN THE BL. SO THEREFORE THINK WILL SEE SCT LIGHT SHOWER
DEVELOP ACROSS MUCH OF THE AREA BY LATE MORNING AND PEAKING AROUND
EARLY AFTERNOON. SOME DRIER AIR MOVING IN FROM THE NORTH MAY CAUSE
SHOWERS TO DIMINISH THERE FIRST...AWAY FROM THE LAKE EFFECT BELTS.
WITH PLENTY OF CLOUDS...HIGHS TO ONLY REACH FROM THE MID 50S NORTH
TO LOW 60S SOUTH.
.LONG TERM...FRIDAY NIGHT THROUGH THURSDAY
ISSUED AT 243 PM CDT THU SEP 10 2015
HIGH PRESSURE WILL BUILD IN ACROSS THE WESTERN GREAT LAKES DURING
THE WEEKEND...DRYING OUT THE WEATHER OVER NORTHEAST WISCONSIN.
HOWEVER IN ADDITION TO DRY WEATHER THE HIGH WILL BRING COOL
TEMPERATURES AS 850 MB TEMPERATURES FALL INTO THE SINGLE DIGITS
ABOVE ZERO. AS THE HIGH BUILDS IN...CLOUDS WILL CLEAR OUT AND
SURFACE WINDS WILL BECOME LIGHT...MAKING FOR IDEAL RADIATIVE
COOLING CONDITIONS. THIS WILL LIKELY PRODUCE AREAS OF FROST ON
FRIDAY NIGHT ACROSS NORTH CENTRAL WISCONSIN...WITH PATCHY FROST
ACROSS THE SAME AREA SATURDAY NIGHT. OF THESE TWO NIGHTS IT LOOKS
LIKE FRIDAY NIGHT WILL BE THE COOLER OF THE TWO NIGHTS...WITH AN
ADVISORY BEING A POSSIBILITY AS LOWS DROP INTO THE MIDDLE 30S.
THERE WILL BE SOME RETURN FLOW SATURDAY NIGHT WITH SLIGHTLY WARMER
TEMPERATURES AS LOWS ONLY DROP TO AROUND 40 DEGREES. HIGHS THIS
WEEKEND WILL BE SEVERAL DEGREES BELOW NORMAL...WITH TEMPERATURES
ONLY EXPECTED TO GET INTO THE 60S.
RETURN FLOW ON THE BACKSIDE OF THE HIGH WILL ALLOW DAYTIME
TEMPERATURES TO REBOUND BACK INTO THE 70S...CLOSE TO NORMAL FOR
THIS TIME OF YEAR...DURING THE EARLY PART OF NEXT WEEK AS THE
HIGH CONTINUES TO PROVIDE DRY WEATHER ACROSS THE WESTERN GREAT
LAKES REGION.
THE NEXT CHANCE FOR RAIN WILL NOT OCCUR UNTIL WEDNESDAY AND
THURSDAY AS A LOW PRESSURE SYSTEM DEVELOPS ACROSS THE PLAINS AND
HEADS EAST THROUGH THE GREAT LAKES REGION. WITH THE HIGH IN PLACE
ACROSS THE EAST FEEDING IN DRY AIR IT WILL MAKE THE EASTWARD
PROGRESS OF THE LOW RATHER SLOW. WITH THIS IN MIND IT APPEARS THE
SLOWER ECMWF SOLUTION IS PREFERRED TO THE QUICKER GFS MODEL. HIGHS
DURING THIS PERIOD AHEAD OF THE COLD FRONT SHOULD STAY IN THE 70S
ACROSS NORTHEAST WISCONSIN.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1148 AM CDT THU SEP 10 2015
THERE WILL BE A CHANCE OF SHOWERS OVER EASTERN WISCONSIN THIS
AFTERNOON AND EVENING AS A COLD FRONT MOVES THROUGH THE AREA. CIGS
REMAIN ALL OVER THE PLACE SO FAR THIS MORNING...BUT WILL SHOW A RISE
TO VFR THIS AFTERNOON AS SOME OF THE LOWER CIGS MIX OUT. PARTIAL
CLEARING IS ANTICIPATED BEHIND THE FRONT...MAINLY OVER CENTRAL AND
NORTH-CENTRAL WI LATE THIS AFTERNOON AND INTO THIS EVENING. THEN
MVFR CLOUDS ARE EXPECTED TO SURGE SOUTHWARD OVERNIGHT ASSOCIATED
WITH AN UPPER LOW. SCT RAIN SHOWERS WILL BE POSSIBLE AT RHI...BUT
THE REST OF THE TAF SITES SHOULD SEE CHANCES FOR SHOWERS INCREASE BY
MID MORNING ON FRIDAY.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......KURIMSKI
AVIATION.......MPC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1148 PM CDT WED SEP 9 2015
.UPDATE...
ISSUED AT 908 PM CDT WED SEP 9 2015
TOUGH LITTLE FORECAST OVERNIGHT WITH MARGINAL INSTABILITY TO THE
WEST MOVING INTO THE AREA..WITH SOME WEAK FORCING. SURFACE LOW
AND FRONT ARE STILL WELL WEST NEAR KABR SOUTH DAKOTA...WITH ABOUT
500-1000 J/KG OF MUCAPE FROM KSUX-KSTC ROUGHLY...AND 250 J/KG HAS
FINALLY SHIFTED INTO THE WESTERNMOST MOST FORECAST AREA. THIS
AXIS REPRESENTS THE STORM ACTIVITY AT 02Z. SO FAR...SHOWER
ACTIVITY HAS DIED AS IT HEADS EAST OUT OF THE MOISTURE AXIS. GOES
WATER VAPOR SHOWING A FEW LITTLE WAVES ACROSS SOUTHERN MN...BUT A
MORE IMPRESSIVE SHORTWAVE TROUGH IN WESTERN SD...BOLTING FOR NERN
IA BY SUNRISE.
THE WESTERN SD WAVE WILL BE THE ONE TO SHIFT THE SURFACE LOW AND
FRONT SEWRD OVERNIGHT AND MOISTURE ALOFT WILL INCREASE ON
ISENTROPIC LIFT ACROSS IA/MN...INTO WI.
OVERALL THE IDEA IS THAT LIFT AND LOW-LEVEL CONVERGENCE AND SOME
850 MB MOISTURE TRANSPORT WILL INCREASE OVERNIGHT AS THE FRONT
MOVES THROUGH AND A BIT OF MUCAPE ARRIVES. A BIT MORE FOCUS
ARRIVES LATER FROM NORTHEAST IA INTO CENTRAL WI AS CONVERGENCE
INCREASES ALONG THE FRONT...AND 850MB MOISTURE TRANSPORT
INCREASES. HAVE INCREASED THE LATE NIGHT RAIN CHANCES FOR THIS
DEVELOPMENT.
BY SUNRISE THE VIGOROUS WESTERN SD TROUGH ARRIVES AND HAVE BUMPED
RAIN CHANCES UP ACROSS SERN MN AND NERN IA MAINLY.
OVERALL LIGHTNING THREAT IS VERY ISOLATED WITH LIMITED CAPE.
&&
.SHORT TERM...(TONIGHT THROUGH THURSDAY NIGHT)
ISSUED AT 208 PM CDT WED SEP 9 2015
BIG PICTURE WATER VAPOR IMAGERY/RAP ANALYSIS SHOWING A CLOSED UPPER
LOW OVER WESTERN ONTARIO WITH A BROAD TROUGH OVER THE
NORTHER/CENTRAL CONUS. AN EMBEDDED MID-LEVEL SHORTWAVE TROUGH WAS
PUSHING INTO MN/DAKOTAS. RADAR MOSAIC SHOWING SCATTERED BAND OF
SHOWERS AND THUNDERSTORMS AHEAD OF THIS WAVE EXTENDING FROM
NORTHWEST WI/EAST CENTRAL MN TO SOUTH CENTRAL MN...MOVING EAST AT 35-
40KT. OTHERWISE...TEMPERATURES AS OF 2 PM RANGED FROM NEAR 70 ACROSS
NORTH CENTRAL WI...TO THE 75-80 DEGREE RANGE ALONG AND SOUTH OF I-90.
FOR THIS EVENING OVERNIGHT...WILL BE WATCHING THE WAVE CONTINUE
MOVING EAST ACROSS OUR AREA. RAP DEPICTING INCREASING 850-700MB
MOISTURE TRANSPORT ALONG WITH INCREASING MUCAPE...HIGHER 500-1000
J/KG SOUTH OF I-90. THEREFORE CARRIED SHRA/TS ALONG AND SOUTH OF I-
90 WITH ISOLATED THUNDER NORTH. MOST MESO MODELS DEPICTING SCATTERED
NATURE TO THIS CONVECTION...SO MAINTAINED 30-50 POPS FOR NOW.
ANOTHER STRONGER MID-LEVEL WAVE/DECENT 500-300MB PV-ADVECTION PUSHES
IN ACROSS THE NORTHERN PLAINS INTO THE UPPER MISSISSIPPI RIVER
VALLEY BY TOMORROW MORNING AND IS EXPECTED TO REINFORCE
SHOWER/THUNDER CHANCES ACROSS THE AREA. WITH EXPECTED SCATTERED
CONVECTION AND CLOUD COVER...WILL SEE COOLER TEMPERATURES WITH HIGHS
ACROSS NORTH CENTRAL WI ONLY IN THE 65-70 DEGREE RANGE AND LOW-MID
70S SOUTH OF I-90.
LOOKS LIKE SHOWER/ISOLATED THUNDER CHANCES PUSH OUT OF THE AREA BY
LATER THURSDAY EVENING WITH CLEARING SKIES THROUGH THE OVERNIGHT
HOURS. WITH DEEPENING MID/UPPER LEVEL TROUGH OVERHEAD AND RATHER
COLD 850MB TEMPS DROPPING INTO THE 1-5C RANGE...WILL SEE OVERNIGHT
LOWS DIP INTO THE 40S MOST LOCATIONS.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 208 PM CDT WED SEP 9 2015
FOR FRIDAY THROUGH SATURDAY NIGHT...
ANOTHER EMBEDDED SHORTWAVE TROUGH COMES DOWN ACROSS THE AREA ON
FRIDAY. STEEP LOW TO MID-LEVEL LAPSE RATES EXPECTED TO GENERATE
QUITE A BIT OF CUMULUS AND SCATTERED SHOWERS...MAINLY ALONG AND EAST
OF THE MISSISSIPPI RIVER. OTHERWISE...A RATHER CHILLY AUTUMN-LIKE
DAY ON TAP AS HIGHS ONLY TOP OFF IN THE UPPER 50S TO THE MIDDLE 60S.
CHILLY DAY FRIDAY AND CLEARING SKIES FRIDAY NIGHT AS SURFACE HIGHS
SETTLES IN WILL SET THE STAGE FOR COLD TEMPERATURES FRIDAY NIGHT
WITH LOWS DIPPING INTO TO THE UPPER 30S/AROUND 40 ACROSS NORTH
CENTRAL WI...TO THE LOWER/MIDDLE 40S ELSEWHERE.
MODELS SHOW THE MID-LEVEL TROUGH PUSHING INTO THE EASTERN GREAT
LAKES/OHIO RIVER VALLEY SATURDAY AS MID-LEVEL RIDGE BUILD INTO OUR
REGION. THIS WILL PROVIDE DRY AND SLIGHTLY WARMER //BUT STILL WELL
BELOW NORMAL// TEMPERATURES IN THE LOW-MID 60S UNDER MOSTLY SUNNY
SKIES.
PLAN ON ANOTHER CLEAR AND COLD SATURDAY NIGHT WITH SURFACE HIGH
OVERHEAD. LOOKS TO BE AN IDEAL RIVER VALLEY/BOG AREA FOG NIGHT WITH
OVERNIGHT LOWS DIPPING INTO THE 40S ONCE AGAIN. DID NOT INCLUDE IN
THE WEATHER GRIDS FOR NOW AS EXACT RIDGE LOCATION COULD CHANGE A
BIT...BUT SOMETHING TO KEEP AN EYE ON NONETHELESS.
FOR SUNDAY THROUGH WEDNESDAY...DAYS 4 TO 7...
GFS AND ECMWF IN AGREEMENT ON A WARMING TREND FOR THIS PERIOD AS LOW
PRESSURE LIFT ACROSS THE NORTHERN PLAINS INTO CANADA. THIS PUTS US
IN WARM SECTOR WITH BROAD-SCALE LIFT ACROSS OUR AREA FOR A CHANCE OF
SHOWERS AND THUNDERSTORMS MAINLY IN THE TUESDAY NIGHT THROUGH
WEDNESDAY TIME FRAME. LOOKS LIKE HIGHS ON SUNDAY IN THE 65-70 DEGREE
RANGE...WARMING BACK INTO THE 70S...OR NEAR SEASONAL NORMALS...BY
WEDNESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1148 PM CDT WED SEP 9 2015
PERIOD OF WEATHER MOVING THROUGH KLSE SHOULD QUICKLY SHIFT EAST.
INSTABILITY STILL IS MOVING ACROSS THE AIRFIELDS OVERNIGHT AND
ANOTHER WEATHER IMPULSE IS MOVING INTO THE AREA BY SUNRISE. SOME
SHRA/TSRA COULD FORM FROM THAT SYSTEM...BUT IT APPEARS IT SHOULD
TRAVEL SOUTH OF THE AIRFIELDS. GENERALLY A VFR FORECAST IS
EXPECTED.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...BAUMGARDT
SHORT TERM...DAS
LONG TERM....DAS
AVIATION...BAUMGARDT
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
145 PM MDT THU SEP 10 2015
.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 230 PM MDT THU SEP 10 2015
TONIGHT...WEAK COLD FRONT WILL RESIDE ACROSS OUR EASTERN COUNTIES
THROUGH EARLY THIS EVENING AND WE MAY SEE ISOLATED TO WIDELY
SCATTERED EVENING SHOWERS AND THUNDERSTORMS ALONG THE COLD FRONT
OVER FAR EASTERN WYOMING AND WESTERN NEBRASKA. EXPECTING THE
PRECIPITATION TO END BY OR SHORTLY AFTER MIDNIGHT. BOUNDARY LAYER
FROM THE NAM SUGGESTING POSSIBLE AREAS OF FOG LATE TONIGHT FROM THE
INTERSTATE 80 SUMMIT EAST ACROSS CHEYENNE TO SIDNEY NEBRASKA.
FRIDAY...COOLER DAY WITH MORE CLOUD COVER AND IN THE WAKE OF THE
PASSING COLD FRONT. ALTHOUGH A LOW AND MID LEVEL THETA-E RIDGE AXIS
WILL LIE ACROSS SOUTHEAST WYOMING IN THE AFTERNOON...WITH MINIMAL
LIFT AND STABLE LOW LEVELS...NO PRECIPITATION EXPECTED.
FRIDAY NIGHT/SATURDAY/SATURDAY NIGHT...DECENT WARMING TREND ON TAP
FOR SATURDAY AS HEIGHTS ALOFT AND THICKNESSES RISE AS THE COOLER
AIRMASS MODERATES. WITH LIMITED LOW AND MID LEVEL MOISTURE AND
LIFT...NO PRECIPITATION ON TAP. NOT AS COOL SATURDAY NIGHT AS
SURFACE LEE TROUGHING INCREASES MIXING AND AS THE AIRMASS CONTINUES
TO SLOWLY MODERATE.
.LONG TERM...(SUNDAY THROUGH THURSDAY)
ISSUED AT 230 PM MDT THU SEP 10 2015
FIRE WEATHER CONCERNS RETURN SUNDAY AS A SURFACE LOW PRESSURE
SYSTEM TRACKS THROUGH MONTANA. GFS 700MB WINDS INCREASING TO
20-25KTS ACROSS OUR WESTERN ZONES WITH AFTERNOON HUMIDITIES
RANGING FRO 7 TO 12 PERCENT ACROSS MUCH OF THE AREA. LIKELY
LOOKING AT RED FLAG CONDITIONS FOR MOST IF NOT OF OUR FIRE ZONES
SUNDAY. THESE WINDY CONDITIONS LIKELY TO CONTINUE INTO MONDAY.
STILL CONCERNS ON WHAT A PACIFIC LOW PRESSURE SYSTEM IS GOING TO
DO TOWARDS MID WEEK. SEEMS TO BE COMING MORE INTO AGREEMENT THAT
THE UPPER LOW WILL PASS NORTH OF WYOMING ACROSS MONTANA. GUIDANCE
SHOWING 700MB WINDS REALLY RAMPING UP MONDAY NIGHT INTO TUESDAY
WITH 45-50KTS FORECAST. CRAIG TO CASPER 700MB GRADIENTS IN EXCESS
OF 60MTRS. WE COULD BE DEALING WITH THE SEASONS FIRST HIGH WIND
EVENT...ESPECIALLY FOR OUR WIND PRONE AREAS. WILL CONTINUE TO
MONITOR THIS AS THE EVENT DRAWS CLOSER.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1116 AM MDT THU SEP 10 2015
WEAK COLD FRONT HAS MADE IT THROUGH CHEYENNE LATE THIS MORNING AND
CONTINUES TO PUSH SOUTHWEST. THIS WILL SET UP AN UPSLOPING
EASTERLY WIND FOR AREAS EAST OF THE LARAMIE RANGE. LATEST SREF
GUIDANCE SHOWING LOWERING CONDITIONS IN FOG/STRATUS FOR THE
SOUTHERN PANHANDLE AND POSSIBLY KCYS BY EARLY FRIDAY MORNING. HAVE
STARTED THE TREND DOWN IN TAFS. HOPEFULLY...WE START SEEING THE
LOWERING TREND IN HRRR GUIDANCE TO BOLSTER CONFIDENCE AND FURTHER
NAIL DOWN TIMING/LOCATIONS.
&&
.FIRE WEATHER...
ISSUED AT 230 PM MDT THU SEP 10 2015
NEAR CRITICAL WINDS AND LOW HUMIDITIES BEING OBSERVED ACROSS
CARBON COUNTY THIS AFTERNOON. STILL BELIEVE THIS WILL BE SHORT
LIVED AS A COLD FRONT PUSHES SOUTH INTO THE AREA. ADDED CLOUDS
SHOULD HELP EASE MIXING DOWN OF WINDS AS WELL. HUMIDITIES AND
WINDS WILL REMAIN BELOW THRESHOLDS FRIDAY AND SATURDAY...THUS
MINIMAL CONCERNS. HOWEVER...ON SUNDAY AND MONDAY...HUMIDITIES AND
WINDS WILL BE APPROACHING CRITICAL THRESHOLDS SO FIRE WEATHER
CONCERNS WILL INCREASE AGAIN.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...RUBIN
LONG TERM...GCC
AVIATION...GCC
FIRE WEATHER...RUBIN
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1119 AM MDT THU SEP 10 2015
.SHORT TERM...(TODAY THROUGH SATURDAY NIGHT)
ISSUED AT 300 AM MDT THU SEP 10 2015
PRETTY QUIET WEATHER WILL CONTINUE LATE THIS WEEK AND INTO THE
WEEKEND WITH NORTHWEST FLOW ALOFT DOMINATING ACROSS THE FRONT
RANGE AND GREAT PLAINS. THE ONLY MINOR FORECAST CONCERN IS A WEAK
COLD FRONT AND ASSOCIATED UPPER LEVEL TROUGH. CURRENT OBS AND IR
SATELLITE LOOP SHOWS THE SLOW MOVING FRONT STILL NORTH OF THE AREA
ACROSS MONTANA. THIS FRONT IS FORECAST TO MOVE INTO NORTHERN
WYOMING EARLY THIS MORNING...AND EVENTUALLY ACROSS SOUTHEAST
WYOMING BY EARLY THIS AFTERNOON. WINDS WILL SHIFT INTO THE NORTH
AND NORTHEAST THIS AFTERNOON WITH SOME SLIGHTLY COOLER AIR MOVING
OVER THE HIGH PLAINS...MAINLY EAST OF THE LARAMIE RANGE. LOW AND
UPPER LEVEL DYNAMICS APPEAR UNFAVORABLE FOR PRECIPITATION AT THIS
TIME...SO KEPT A 20 PERCENT CHANCE OF SHOWERS MAINLY ACROSS
WESTERN NEBRASKA DUE TO SOME MARGINAL INSTABILITY AND WEAK UPPER
LEVEL DIFLUENCE AS A JET MAX AT 250MB BRUSHES OUR FAR EASTERN
ZONES THROUGH FRIDAY. CAN NOT RULE OUT SOME PATCHY FOG ALONG AND
NEAR THE LARAMIE RANGE EARLY FRIDAY MORNING AS WELL DUE TO MOIST
UPSLOPE FLOW AND COOL TEMPERATURES. TEMPERATURES ON FRIDAY ARE
EXPECTED TO BE SLIGHTLY BELOW NORMAL FOR THIS TIME OF THE YEAR AND
GENERALLY IN THE UPPER 60S TO MID 70S.
UPPER LEVEL RIDGE AXIS WILL BUILD BACK INTO THE FORECAST AREA FOR
SATURDAY WITH HIGH TEMPERATURES RETURNING TO THE 80S ACROSS MOST
OF THE FORECAST AREA. DRY CONDITIONS WILL CONTINUE OVER WYOMING
AND WESTERN NEBRASKA.
.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 315 AM MDT THU SEP 10 2015
WARM AND DRY LATE THIS WEEKEND INTO EARLY NEXT WEEK AS NORTHWEST
FLOW ALOFT FLATTENS OUT. HIGH TEMPERATURES WILL RUN ABOUT 10
DEGREE ABOVE THE SEASONAL NORMALS FOR MID SEPTEMBER WITH HIGHS
GENERALLY FROM THE MID 70S WEST TO MID 80S EAST. FORECAST
UNCERTAINTY CREEPS IN LATE IN THE FORECAST PERIOD. EXTENDED MODELS
DISAGREE TO THE EXTENT THAT A TROUGH WILL DIG ACROSS THE WESTERN
CONUS. 00Z GFS IS MORE AGGRESSIVE THAN THE ECMWF WITH SHORTWAVE
ENERGY ROUNDING THE BASE OF THE UPPER LEVEL OVER WYOMING ON
TUESDAY. THE GFS SOLUTION WOULD BRING SCATTERED SHOWERS AND
THUNDERSTORMS TO THE AREA TUESDAY INTO TUESDAY NIGHT ALONG WITH
COOLER TEMPERATURES...ESPECIALLY BY WEDNESDAY. THE ECMWF KEEPS THE
SHORTWAVE ENERGY WELL NORTH OF THE FORECAST AREA WITH THE UPPER
TROUGH AXIS WELL OFF TO THE WEST. NOT BITING ON ANY SOLUTION AT
THIS POINT BUT LEANING TOWARD THE EC. WILL WATCH MODEL TRENDS THE
NEXT FEW DAYS. REGARDLESS IT WILL MAINLY BE DRY THROUGH THE
EXTENDED FORECAST PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1116 AM MDT THU SEP 10 2015
WEAK COLD FRONT HAS MADE IT THROUGH CHEYENNE LATE THIS MORNING AND
CONTINUES TO PUSH SOUTHWEST. THIS WILL SET UP AN UPSLOPING
EASTERLY WIND FOR AREAS EAST OF THE LARAMIE RANGE. LATEST SREF
GUIDANCE SHOWING LOWERING CONDITIONS IN FOG/STRATUS FOR THE
SOUTHERN PANHANDLE AND POSSIBLY KCYS BY EARLY FRIDAY MORNING. HAVE
STARTED THE TREND DOWN IN TAFS. HOPEFULLY...WE START SEEING THE
LOWERING TREND IN HRRR GUIDANCE TO BOLSTER CONFIDENCE AND FURTHER
NAIL DOWN TIMING/LOCATIONS.
&&
.FIRE WEATHER...
ISSUED AT 231 AM MDT THU SEP 10 2015
ELEVATED FIRE WEATHER CONCERNS THIS AFTERNOON FOR LOCATIONS WEST
OF THE LARAMIE RANGE. WINDS ARE EXPECTED TO BE WEAKER COMPARED TO
THE LAST FEW DAYS AS A COLD FRONT MOVES SOUTHWARD ACROSS EASTERN
WYOMING. THIS FRONT WILL RESULT IN WINDS SHIFTING INTO THE NORTH
OR NORTHEAST AT THE SURFACE...WHILE INCREASING RELATIVE HUMIDITIES
BY 5 PERCENT BY LATE THIS AFTERNOON DUE TO THE SLIGHTLY COOLER
AIRMASS. STILL...A FEW LOCATIONS ACROSS CARBON AND ALBANY COUNTIES
MAY SEE RED FLAG CRITERIA BRIEFLY EARLY THIS AFTERNOON EVEN THOUGH
COVERAGE WILL BE LIMITED. AFTER A FEW DAYS OF LIGHT WINDS AND
SOMEWHAT HIGHER HUMIDITIES...CRITICAL FIRE WEATHER CONDITIONS MAY
RETURN BY SUNDAY.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...TJT
LONG TERM...SML
AVIATION...GCC
FIRE WEATHER...TJT
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
422 AM EDT SAT SEP 12 2015
.SYNOPSIS...
AN APPROACHING COLD FRONT WILL MOVE THROUGH THE FORECAST AREA THIS
EVENING. DRY AND COOLER HIGH PRESSURE WILL DOMINATE BEHIND THE
FRONT SUNDAY THROUGH WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
THE APPROACHING COLD FRONT WILL MOVE THROUGH THE FORECAST AREA
THIS EVENING. THE HRRR DISPLAYS NUMEROUS SHOWERS AHEAD OF THE
FRONT MAINLY IN THE EAST PART ASSOCIATED WITH AN H85 JET TODAY.
CONVERGENCE NEAR THE FRONT AND COOLING ASSOCIATED WITH THE UPPER
TROUGH SUPPORTS A CONTINUED SHOWER CHANCE INTO THE EVENING.
THUNDERSTORMS MAY ALSO OCCUR. THE MODELS SHOW SIGNIFICANT SHEAR
WITH H85 WINDS 30 TO 35 KNOTS IN THE EAST PART. HOWEVER...THE
SHEAR APPEARS GREATEST EARLY TODAY AND CLOUDINESS SHOULD LIMIT
INSTABILITY. THE NAM DISPLAYS WEAK INSTABILITY WITH SURFACE-BASED
LI/S AROUND -3. THE SEVERE THUNDERSTORM CHANCE IS LOW. DRYING WILL
OCCUR LATE TONIGHT BEHIND THE FRONT. USED THE GUIDANCE CONSENSUS
FOR THE TEMPERATURE FORECAST TODAY. MIXING ASSOCIATED WITH THE
FRONT FAVORS THE WARMER GUIDANCE TEMPERATURES TONIGHT.
&&
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
THE DRY AIR MASS MOVING INTO THE FORECAST AREA WILL DOMINATE
SUNDAY AND SUNDAY NIGHT. THE TEMPERATURE GUIDANCE WAS CLOSE WITH
HIGHS SUNDAY MAINLY IN THE LOWER 80S AND LOWS SUNDAY NIGHT IN THE
LOWER AND MIDDLE 50S. THESE LOW TEMPERATURES WILL BE THE COOLEST
WE HAVE EXPERIENCED SINCE MAY.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
THE GFS AND ECMWF DISPLAY HIGH PRESSURE CENTERED NEAR THE
FORECAST AREA MONDAY. THE MODELS HAVE RIDGING IN THE ATLANTIC
WITH A LONG-FETCH EASTERLY FLOW INTO THE FORECAST AREA DURING THE
REST OF THE MEDIUM-RANGE PERIOD. THE MODELS SHOW UPPER RIDGING
EARLY BUT WEAK TROUGHING DURING THE REST OF THE PERIOD. THE ECMWF
WAS MORE PROGRESSIVE SHIFTING DEEPER MOISTURE INTO THE FORECAST
AREA FROM THE SOUTH WEDNESDAY. USED AN AVERAGE OF THE GFS AND
ECMWF MOS FOR THE POP FORECAST. THE MOS INDICATES BELOW NORMAL
TEMPERATURES MONDAY WITH NEAR NORMAL TEMPERATURES DURING THE REST
OF THE PERIOD.
&&
.AVIATION /09Z SATURDAY THROUGH WEDNESDAY/...
VFR CONDITIONS EXPECTED THROUGH THE PERIOD...WITH BRIEF MVFR IN
SHOWERS AND THUNDERSTORMS.
SURFACE FRONT CONTINUES MOVING EASTWARD TOWARD THE REGION AND
WILL CROSS THE TAF SITES THROUGH MID AFTERNOON. REGIONAL RADAR
INDICATES MOST OF THE SHOWERS HAVE DISSIPATED WITH MID LEVEL
CLOUDS BLANKETING THE AREA. CONFIDENCE IN SHOWERS IMPACTING THE
TAF SITES IS CURRENTLY LOW SO HAVE REMOVED MENTION FROM THE TAFS
AND WILL UPDATE AS CONFIDENCE IMPROVES. EXPECT ANY RESTRICTIONS IN
SHOWERS OR THUNDERSTORMS TO BE BRIEF. WINDS WILL REMAIN AROUND 5
KNOTS OVERNIGHT PREVENTING FOG...THEN INCREASE TO 10 KNOTS WITH
GUSTS TO 20 KNOTS BETWEEN 14Z AND 13/00Z.
EXTENDED AVIATION OUTLOOK... NO SIGNIFICANT IMPACTS TO AVIATION
EXPECTED SUNDAY THROUGH WEDNESDAY.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
99
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
357 AM EDT SAT SEP 12 2015
.SYNOPSIS...
AN APPROACHING COLD FRONT WILL MOVE THROUGH THE FORECAST AREA THIS
EVENING. DRY AND COOLER HIGH PRESSURE WILL DOMINATE BEHIND THE
FRONT SUNDAY THROUGH WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
THE APPROACHING COLD FRONT WILL MOVE THROUGH THE FORECAST AREA
THIS EVENING. THE HRRR DISPLAYS NUMEROUS SHOWERS AHEAD OF THE
FRONT MAINLY IN THE EAST PART ASSOCIATED WITH AN H85 JET TODAY.
CONVERGENCE NEAR THE FRONT AND COOLING ASSOCIATED WITH THE UPPER
TROUGH SUPPORTS A CONTINUED SHOWER CHANCE INTO THE EVENING.
THUNDERSTORMS MAY ALSO OCCUR. THE MODELS SHOW SIGNIFICANT SHEAR
WITH H85 WINDS 30 TO 35 KNOTS IN THE EAST PART. HOWEVER...THE
SHEAR APPEARS GREATEST EARLY TODAY AND CLOUDINESS SHOULD LIMIT
INSTABILITY. THE NAM DISPLAYS WEAK INSTABILITY WITH SURFACE-BASED
LI/S AROUND -3. THE SEVERE THUNDERSTORM CHANCE IS LOW. DRYING WILL
OCCUR LATE TONIGHT BEHIND THE FRONT. LEANED TOWARD THE WARMER
TEMPERATURE GUIDANCE JUST AHEAD OF THE FRONT TODAY. MIXING
ASSOCIATED WITH THE FRONT FAVORS THE WARMER GUIDANCE TEMPERATURES
TONIGHT.
&&
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
THE DRY AIR MASS MOVING INTO THE FORECAST AREA WILL DOMINATE
SUNDAY AND SUNDAY NIGHT. THE TEMPERATURE GUIDANCE WAS CLOSE WITH
HIGHS SUNDAY MAINLY IN THE LOWER 80S AND LOWS SUNDAY NIGHT IN THE
LOWER AND MIDDLE 50S. THESE LOW TEMPERATURES WILL BE THE COOLEST
WE HAVE EXPERIENCED SINCE MAY.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
THE GFS AND ECMWF DISPLAY HIGH PRESSURE CENTERED NEAR THE
FORECAST AREA MONDAY. THE MODELS HAVE RIDGING IN THE ATLANTIC
WITH A LONG-FETCH EASTERLY FLOW INTO THE FORECAST AREA DURING THE
REST OF THE MEDIUM-RANGE PERIOD. THE MODELS SHOW UPPER RIDGING
EARLY BUT WEAK TROUGHING DURING THE REST OF THE PERIOD. THE ECMWF
WAS MORE PROGRESSIVE SHIFTING DEEPER MOISTURE INTO THE FORECAST
AREA FROM THE SOUTH WEDNESDAY. USED AN AVERAGE OF THE GFS AND
ECMWF MOS FOR THE POP FORECAST. THE MOS INDICATES BELOW NORMAL
TEMPERATURES MONDAY WITH NEAR NORMAL TEMPERATURES DURING THE REST
OF THE PERIOD.
&&
.AVIATION /07Z SATURDAY THROUGH WEDNESDAY/...
VFR CONDITIONS EXPECTED THROUGH THE PERIOD...WITH BRIEF MVFR IN
SHOWERS AND THUNDERSTORMS.
SURFACE FRONT CONTINUES MOVING EASTWARD TOWARD THE REGION AND
WILL CROSS THE TAF SITES THROUGH MID AFTERNOON. REGIONAL RADAR
INDICATES MOST OF THE SHOWERS HAVE DISSIPATED WITH MID LEVEL
CLOUDS BLANKETING THE AREA. CONFIDENCE IN SHOWERS IMPACTING THE
TAF SITES IS CURRENTLY LOW SO HAVE REMOVED MENTION FROM THE TAFS
AND WILL UPDATE AS CONFIDENCE IMPROVES. EXPECT ANY RESTRICTIONS IN
SHOWERS OR THUNDERSTORMS TO BE BRIEF. WINDS WILL REMAIN AROUND 5
KNOTS OVERNIGHT PREVENTING FOG...THEN INCREASE TO 10 KNOTS WITH
GUSTS TO 20 KNOTS BETWEEN 14Z AND 13/00Z.
EXTENDED AVIATION OUTLOOK... NO SIGNIFICANT IMPACTS TO AVIATION
EXPECTED SUNDAY THROUGH WEDNESDAY.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
99
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
1121 PM MDT FRI SEP 11 2015
.AVIATION...
06Z TAF CYCLE
UPPER RIDGE CENTERED OVER GREAT BASIN WITH DRY NW-NLY FLOW ALF.
MOIST LOW LEVEL UPSLOPE FLOW INTO THE EAST SLOPES CENTRAL MT
CHAIN...OCCASIONAL MT OBSCURATIONS IN AREAS MVFR/IFR CIGS/VSBYS IN
BR PERSISTING UNTIL AROUND 12/16Z FROM THE CENTRAL MT CHAIN OVER
THE ERN PLAINS. SOME MVFR CIGS MAY BLEED INTO THE RGV AFT 06Z ON
GAP WINDS...ESPECIALLY AT KSAF. LATEST SHORT TERM MODELS HAVE
BACKED OFF CONSIDERABLY ON PREVIOUSLY FORECASTED LIGHT PRECIPITATION
WHICH WAS TO HAVE DEVELOPED ACROSS PORTIONS NE/E CENTRAL NM BEFORE
12Z...SO REMOVED FROM KLVS/KTCC TAFS.
&&
.PREV DISCUSSION...333 PM MDT FRI SEP 11 2015...
.SYNOPSIS...
A BACK DOOR COLD FRONT SLIDING INTO EASTERN NEW MEXICO TODAY WILL
CONTINUE TO CREATE GUSTY WINDS...PARTICULARLY BELOW CANYONS IN THE
RIO GRANDE VALLEY. AREAS ON THE EAST SIDE OF ALBUQUERQUE MAY GUST UP
TO 35 MPH THIS EVENING. ISOLATED THUNDERSTORMS WILL DEVELOP OVER THE
STATE THIS WEEKEND...ESPECIALLY THE SOUTHERN HIGH TERRAIN. A SLIGHT
UPTICK IN STORM COVERAGE IS EXPECTED FOR WESTERN NEW MEXICO MONDAY
AND TUESDAY. DRIER AND BREEZY CONDITIONS WILL RETURN TO THE STATE
NEXT WEEK BEFORE A POTENTIAL INCREASE IN MOISTURE BY NEXT FRIDAY.
&&
.DISCUSSION...
THE POST-FRONTAL INVERSION OVER EASTERN NM IS HOLDING STRONG AND
CAPPING CHANCES AT RELEASING WHAT LITTLE SURFACE INSTABILITY IS
PRESENT OVER THE AREA. THIS IS ALSO EVIDENCED BY SCATTERED WAVE
CLOUDS ALONG AND EAST OF THE CENTRAL MT CHAIN. FORCING ALONG THE
SURFACE FRONT AND STRONG HEATING OVER CHAVES COUNTY IS PROVIDING
INSTABILITY FOR AT LEAST ISOLD ACTIVITY. A FEW MEAGER SHOWERS ARE
ATTEMPTING TO FIRE UP OVER THE NORTHERN HIGH TERRAIN WITH LITTLE
SUCCESS.
THE LATEST HRRR/RUC AND LOCAL WRF AGREE WITH THE SPC SSEO THAT THE
VAST MAJORITY OF ACTIVITY WILL TAPER OFF AFTER SUNSET. THE 12Z GFS
WAS STILL VERY WET FOR THE HIGH PLAINS THIS EVENING BUT REMAINDER OF
DETERMINISTIC GUIDANCE IS ON THE DRY SIDE. THE 18Z NAM STILL SHOWS
LOW CLOUDS REDEVELOPING OVER THE EAST WITH PERHAPS SOME LIGHT RAIN
OVERNIGHT. OVERALL LOWERED POPS AND REMOVED MENTION OF THUNDER
AFTER MIDNIGHT. THE OTHER STORY HAS BEEN GAP WINDS IN THE RIO
GRANDE VALLEY...WHICH ARE STILL PROGGED TO INCREASE DURING THE
EVENING. THE 19Z HRRR HAS DELAYED THE PEAK WINDS FOR THE ABQ EAST
SIDE UNTIL BTWN 8PM AND 1AM...WHICH IS CONSISTENT WITH THE LATEST
MET/MAV/ECS MOS GUIDANCE.
THIS WEEKEND LOOKS GENERALLY TRANQUIL AT THIS TIME WITH ONLY ISOLD
STORMS RECYCLING UNDER THE H5 RIDGE CRESTING EASTWARD FROM THE GREAT
BASIN. THE BEST STORM CHANCES WILL FOCUS OVER THE HIGHER TERRAIN OF
CATRON COUNTY AS INCREASINGLY MOIST SOUTHWEST FLOW ARRIVES OVER THE
AREA. TEMPS WILL REBOUND SEVERAL DEGREES SATURDAY OVER THE EAST THEN
BECOME HOT AGAIN BY SUNDAY WITH BETTER KATABATIC FLOW.
MODELS ARE STILL STRUGGLING WITH MOISTURE DELIVERY MONDAY/TUESDAY AS
SEVERAL COMPLEX UPPER FEATURES SHEAR EASTWARD AHEAD OF A DEVELOPING
LARGE SCALE UPPER TROUGH ALONG THE WEST COAST. IT APPEARS THAT THE
WESTERN THIRD WILL STILL FAVOR ISOLATED STORMS...HOWEVER TRENDS ARE
EVEN DRIER. LEE TROUGHING INCREASING OVER THE EAST WILL ALLOW FOR
WINDS TO TREND UP WITH HOT TEMPS ONCE AGAIN.
EXTENDED TRENDS TOWARD A WETTER PATTERN ARE ADVERTISED NOW BY BOTH
THE GFS AND ECMWF BEYOND FRIDAY. THERE ARE SOME INTERESTING FEATURES
TO ANALYZE AS AN ELONGATED UPPER RIDGE DEVELOPS OVER NORTHERN MEXICO
WITH FAST WSW FLOW ALOFT OVER THE NORTHERN ROCKIES. THE 700-500MB
LEVEL MOISTURE PATTERN HAS INDICATIONS OF A TAP TO THE EASTERN
PACIFIC. THIS COULD BE AN INITIAL SIGN OF THE LONG ANTICIPATED
ACTIVE SUBTROPICAL JET MORE COMMON WITH EL NINO IN THE SW CONUS.
GUYER
&&
.FIRE WEATHER...
THE BACK DOOR COLD FRONT ARRIVED EARLIER THAN SCHEDULED TODAY
BRINGING STABLER AIR OVER THE FIRE WEATHER FORECAST AREA. THE FRONT
DID BRING SOME LOW LEVEL MOISTURE INTO THE AREA AND THIS WILL RECYCLE
ON SATURDAY AS AN UPPER HIGH OVER THE GREAT BASIN BEGINS TO MIGRATE
IN THIS DIRECTION. MAINLY ISOLATED SHOWERS AND THUNDERSTORMS ARE
EXPECTED SATURDAY...EXCEPT FOR SOME SCATTERED ACTIVITY OVER THE SW
MOUNTAINS. TEMPERATURES AND VENTILATION WILL GENERALLY TREND UPWARD
WHILE HUMIDITIES TREND DOWNWARD.
SUNDAY THE UPPER HIGH WILL WEAKEN INTO A RIDGE OF HIGHER PRESSURE
WITH AN AXIS ORIENTED NORTH TO SOUTH ALONG NEW MEXICOS RIO GRANDE
VALLEY. THIS WILL FUNNEL MOISTURE NORTHWARD OVER WESTERN PARTS OF
THE FORECAST AREA WHERE AN UPTICK IN HUMIDITIES AND THUNDERSTORM
COVERAGE IS EXPECTED WITH A SLIGHT DROP IN TEMPERATURES. ELSEWHERE
TEMPERATURES WILL CONTINUE TO WARM WHILE HUMIDITIES FALL. HIGH
HAINES INDICES IN THE 5 TO 6 RANGE ARE EXPECTED ALONG AND NORTH OF I-
40.
MONDAY THROUGH THE MIDDLE OF NEXT WEEK MOISTURE SHOULD CONTINUE TO
FUNNEL OVER WESTERN AREAS...AND TO A LESSER EXTENT CENTRAL
AREAS...AS A LONG WAVE TROUGH TAKES SHAPE OVER THE W COAST.
SHORTWAVE TROUGHS WILL EJECT NORTHEASTWARD FROM THIS FEATURE ACROSS
THE NORTHERN AND CENTRAL ROCKIES MONDAY AND TUESDAY...INTERACTING
WITH THIS MOISTURE AND STRENGTHENING THE FLOW ALOFT FOR AN UPTICK IN
SHOWER AND THUNDERSTORM ACTIVITY ON THESE DAYS. THE MONSOON PLUME
MAY WEAKEN SOME WEDNESDAY AND THURSDAY IF SOME DRIER AIR CAN GET
ENTRAINED IN THE WAKE OF MONDAY AND TUESDAYS SHORTWAVES AS DEPICTED
BY THE GFS AND ECMWF. ALSO ON MONDAY...A LEE TROUGH SHOULD TRIGGER
BREEZY TO WINDY CONDITIONS ACROSS THE NORTHEAST HIGHLANDS AND PLAINS.
44
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
550 AM EDT SAT SEP 12 2015
.SYNOPSIS...
A FEW WAVES OF LOW PRESSURE AT THE SURFACE WILL MOVE NORTHEAST
ACROSS THE STATE TODAY...AHEAD OF AN UNUSUALLY DEEP UPPER TROUGH
STRETCHED FROM THE UPPER GREAT LAKES TO LOWER OHIO VALLEY THIS
MORNING. THE TROUGH WILL SLOWLY TRACK OVER CENTRAL PENNSYLVANIA
AND LIFT EAST OF THE REGION LATE THIS WEEKEND. FAIR AND WARMER
CONDITIONS WILL RETURN BEGINNING MONDAY AND CONTINUE THROUGH MOST
OR ALL OF NEXT WEEK AS A LARGE AREA OF HIGH PRESSURE DRIFTS OVER
THE OHIO VALLEY AND MID ATLANTIC REGION.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
DEEP DRY AIR IS HOLDING TOUGH ACROSS CENTRAL AND ERN PENN EARLY
THIS MORNING. LOOKING BACK AT THE VARIOUS MODEL GUIDANCE WE HAD 24
HOURS AGO...THE FAVORABLE JET DYNAMICS/STRONG UVVEL FOR STEADY
LIGHT TO MDT RAIN HAVE SHIFTED ABOUT 75-100 NM FURTHER WEST.
CORRESPONDING SFC LOW DEVELOPMENT AND GRADUAL STRENGTHENING
BENEATH THE LEFT EXIT REGION OF A 115 KT SSWRLY 300 MB JET WILL
OCCUR ACROSS NRN WVA EARLY TODAY /INVOF KMGW/ WITH THE TRACK OF
THE LOW LIKELY CLOSE TO THE I-99/ROUTE 220 CORRIDOR IN CENTRAL
PENN.
THIS TRACK HAS FAVORED THE STEADIEST AND HEAVIEST RAIN ACROSS THE
ALLEGHENIES OF NWRN PENN SO FAR...AND THE HRRR OVER THE PAST
SEVERAL HOURS HAS BEEN DEPICTING GRADUAL EASTWARD PROGRESSION AND
SOME DISSIPATION OF THE INITIAL RAIN SHIELD AS IT NEARS THE
INTERSTATE 99 AND RT 220 CORRIDOR IN THE 10Z-15Z PERIOD TODAY.
A RATHER POTENT SHORTWAVE /MIGRATING NNE THROUGH THE MORE
EXTENSIVE APPROX 115 KT UPPER JET CORE/ WILL HELP TO BLOSSOM A
SECOND AREA OF STEADY MODERATE RAIN LATE THIS MORNING THROUGH THE
MID AFTERNOON. THIS WAVE WILL BE ASSOCIATED WITH ELEVATED LIFTED
INDICES NEARING ZERO...WHICH WILL SUPPORT THE CHANCE OF SOME
EMBEDDED/LOW-TOPPED TSRA WITH BRIEFLY HEAVY RAIN. THE MAIN THREAT
FOR TSRA APPEARS TO BE ACROSS OUR FAR SE ZONES AFTER 19 OR 20Z.
03Z SREF SHOWS THE PROB OF CAPE EXCEEDING 1000 J/KG AT ABOUT 30
PERCENT ACROSS SOUTHERN LANCASTER COUNTY WITH LESSER AMOUNTS
JUST TO THE NORTH.
SPC HAS PLACED MOST OF THE LOWER SUSQ VALLEY AND A LARGE PORTION
OF THE MID SUSQ VALLEY AND WRN POCONOS UNDER A MARGINAL RISK OF
SVR WX THIS AFTN/EVEN. ALTHOUGH INCREASING CLOUD COVER LATER THIS
MORNING WILL LIKELY LIMIT DESTABILIZATION...INCREASING MID LVL
FLOW/DEEP LYR SHEAR IMPLIES SOME RISK OF STRONGER STORMS ACROSS
THE LOWER SUSQ VALLEY...WHERE MDLS PRODUCE AFTN CAPES ARND 500
J/KG.
WILL WHITTLE AWAY AND DELAY THE ONSET OF RAIN/SHOWERS ACROSS THE
EASTERN HALF OF THE CWA A LITTLE MORE...THROUGH THE MID MORNING
HOURS IN CENTRAL PENN...AND UNTIL AROUND 15Z FOR MUCH OF THE SUSQ
VALLEY...WHILE MAINTAINING THE SAME POPS /BUT SLIGHTLY LOWER QPF/
ACROSS THE WESTERN MTNS THROUGH 12Z.
TEMPS EARLY TODAY ARE IN A TIGHT...5 DEG F RANGE OF 55-60F ACROSS
THE REGION AT 09Z...AND WILL RISE ONLY VERY SLOWLY ACROSS CENTRAL
AND WESTERN PENN THIS MORNING AS RAIN OVERSPREADS THE REGION.
WARMEST TEMPS TODAY WILL BE OVER THE SUSQ VALLEY WHERE HIGHS WILL
REACH THE LOWTO MID 70S...WHILE THE NW MTNS AND LAUREL HIGHLANDS
SEE THE MERCURY HOLD BETWEEN 59-62F.
HAVE MODIFIED POPS AND STORM TOTAL RAINFALL SLIGHTLY...BUT STILL
FEEL THAT MODEL CONSENSUS STILLS POINTS TWD A BENEFICIAL AMOUNT
OF ONE-HALF TO 1.25 INCHES ACROSS THE REGION BY LATE TONIGHT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/...
THE RAIN SHOULD TAPER OFF WITH THE PASSAGE OF SFC COLD FRONT LATE
IN THE DAY ACROSS THE LAUREL HIGHLANDS... AND DURING THE EVENING
HOURS ACROSS THE REST OF CENTRAL PA.
PLENTY OF CLOUDS AND LINGERING SHOWERS WILL OCCUR LATER TONIGHT
AND SUNDAY AS THE CORE OF THE COLD AIR ALOFT TRACKS RIGHT OVERHEAD
SUNDAY AFTERNNOON AND NIGHT. A GRADUALLY INCREASING NW BREEZE WILL
OCCUR FOR LATE TONIGHT AND SUNDAY. WIND GUSTS OF 15-20 KTS FROM
THE NW ARE EXPECTED IN MOST PLACES SUNDAY AFTERNOON.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
THE BULK OF THE SENSIBLE WEATHER WILL OCCUR VERY EARLY IN THIS
EXTENDED FCST PERIOD AS WE EXPERIENCE THE EFFECTS OF THE UPPER
TROUGH CLOSING OFF AS IT DROPS THROUGH THE EASTERN GR LAKES AND
EVENTUALLY MOVES OVERHEAD.
ENSEMBLES INDICATE THE RAIN TAPERING TO SHOWERS AND ENDING SUNDAY
NIGHT. THIS WILL SET THE STAGE FOR ANOTHER EXTENDED PERIOD OF DRY
WEATHER WHICH SHOULD LAST THROUGH THE END OF THE WORK WEEK AND
POSSIBLY INTO THE WEEKEND AS THE MEAN UPPER RIDGE IS PROJECTED TO
SURGE BACK INTO THE NERN US.
GEFS AND ECMWF HINT AT SHORTWAVE ENERGY BEGINNING TO CHEW THE TOP
OFF THE RIDGE BY NEXT WEEKEND WHICH LEADS TO THE MENTION OF A
SMALL CHANCE OF SHOWERS...BUT CONFIDENCE IS LOW THIS FAR OUT.
UNTIL THEN IT LOOKS LIKE ANOTHER BOUT OF LATE SUMMER WARMTH ON THE
WAY.
&&
.AVIATION /09Z SATURDAY THROUGH WEDNESDAY/...
LOW PRESSURE TROUGH WILL DEEPEN OVER THE REGION TODAY AND
GRADUALLY LIFT NORTHEAST THROUGH SUNDAY. IN ADDITION...A SURFACE
COLD FRONT WILL WORK SLOWLY EAST TODAY.
SHOWERS WILL IMPACT WESTERN TERMINALS OVERNIGHT...POTENTIALLY
BRINGING REDUCTIONS AFTER 09Z. AN AREA OF WIDESPREAD RAIN WILL
PUSH IN FROM THE WEST AND SOUTH /BEHIND THE SURFACE COLD FRONT/
DURING THE DAY...WITH CONDITIONS DETERIORATING FROM WEST TO EAST.
REDUCTIONS ARRIVE MIDDAY AT KUNV AND MID AFTERNOON IN THE EAST.
WESTERN AREAS WILL FALL TO IFR WITH CENTRAL AND EASTERN TERMINALS
GENERALLY FALLING INTO THE MVFR CATEGORY. EVEN ENOUGH MID LEVEL
INSTABILITY DEVELOPS THIS AFTERNOON THAT AN ISOLATED TSTM CAN/T
BE RULED OUT IN THE SUSQ VALLEY.
RAIN TAPERS TO SHOWERS THIS EVENING AS MAIN WAVE BEGINS TO
EXIT...BUT CIGS DROP TO A FAIRLY WIDESPREAD IFR /MVFR SE/ AS
CENTER OF UPPER LOW ARRIVES AND LOW LEVEL FLOW BACKS AROUND TO
THE W-NW AND INCREASES.
AS TROUGH LIFTS TO THE NE....MUCH OF SUNDAY WILL FEATURE GUSTY
WINDS...MVFR CONDITIONS AND SHOWERS /MOST NUMEROUS IN THE NW/.
OUTLOOK...
SUN...CIG RESTRICTIONS AND SCT SHOWERS EARLY...WITH GRADUAL
IMPROVEMENT.
MON-WED...SCT MORNING VALLEY FOG...OTHERWISE VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...LAMBERT
LONG TERM...LA CORTE
AVIATION...RXR
AREA FORECAST DISCUSSION
NWS TAUNTON MA
1045 AM EDT SAT SEP 12 2015
.SYNOPSIS...
WEAK HIGH PRESSURE WILL BRING DRY AND MILD CONDITIONS THROUGH
MOST OF THIS AFTERNOON BUT SHOWERS WILL RETURN LATE THIS
AFTERNOON AND ESPECIALLY TONIGHT. SUNDAY WILL BE WET WITH THE
POSSIBILITY OF SOME THUNDERSTORMS ALONG WITH GUSTY WINDS. WHILE A
LIGHT TO MODERATE RAIN IS FORECAST...CAN NOT RULE OUT IT BEING
HEAVY AT TIMES. HIGH PRESSURE BUILDS EAST ACROSS THE MID ATLC
STATES EARLY NEXT WEEK. THIS RIDGE WILL EXPAND ALONG THE EASTERN
SEABOARD... DOMINATING THROUGH MOST OF NEXT WEEK WITH DRY
CONDITIONS. EXPECT TEMPERATURES TO WARM DURING THE
WEEK...ESPECIALLY FROM WEDNESDAY THROUGH FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
1025 AM UPDATE...
CLOUD TRENDS... AREA OF LOW CLOUDINESS/FOG FROM BOSTON TO NORWOOD
TO FITCHBURG HAS BEEN PIVOTING AND NOT MOVING. HOWEVER IT IS
SHOWING SIGNS OF ERODING FROM THE EAST. HRRR MODEL DEPICTS THIS
NICELY AND ACTUALLY SHIFTS THIS BAND OF LOW CLOUDS WESTWARD INTO
CENTRAL MA THIS AFTERNOON. LOW CLOUDS IN CT RIVER VALLEY AND
ACROSS NORTHERN CT AND WESTERN RI ARE ERODING BUT NEW CUMULUS
CLOUDS ARE ALREADY POPPING UP. THICK HIGH MID AND HIGH CLOUDINESS
CONTINUES TO PROGRESS STEADILY EASTWARD ACROSS PA/NY/NORTHERN NJ
AND WILL MOVE ACROSS WESTERN PORTIONS OF SOUTHERN NEW ENGLAND THIS
AFTERNOON. ADJUSTED GRIDS FOR CURRENT TRENDS.
PRECIPITATION TRENDS...BAND OF SHOWERS SOUTH OF LONG ISLAND HAS
DISSIPATED. SHOWERS ASSOCIATED WITH THE CLOUDINESS MENTIONED ABOVE
WAS MOVING EASTWARD ACROSS NORTHEAST PA AND CENTRAL NY STATE. OUR
SHOWER CHANCES WILL INCREASE IN WESTERN SECTIONS THIS AFTERNOON
AS IT PROGRESSES INTO WESTERN NEW ENGLAND. COULD ALSO SEE A FEW
SHOWERS POP UP FARTHER TO THE EAST IN EASTERN CT/CENTRAL MA/NORTHERN
RI LATER THIS AFTERNOON. NO ADJUSTMENTS MADE TO FORECAST POPS.
LIGHT PRESSURE GRADIENT WILL ALLOW FOR SEA BREEZES LATE THIS
INTO THE EARLY AFTERNOON. TEMPERATURES HAVE CLIMBED TO LOWER 70S
ALONG THE SOUTH COAST AND ISLANDS...SO RAISED MAXES THERE BY A
COUPLE OF DEGREES.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/...
TONIGHT...LOW LEVEL SOUTHEAST WINDS DEVELOP AND STRENGTHEN THROUGH
THE NIGHT AS A LOW APPROACHES. RATHER GOOD AGREEMENT IN THE 12/00Z
GUIDANCE THAT A WARM FRONT WILL REACH THE SOUTH COAST OF NEW
ENGLAND AROUND MIDNIGHT SUNDAY. THIS FRONT SLOWLY MOVES NORTH INTO
OUR REGION LATE. THIS FRONT WILL BE THE FOCUS FOR SHOWERS.
GREATEST CHANCE FOR SHOWERS WOULD BE NEAREST THE FRONT ACROSS
AREAS SOUTH OF THE MASS PIKE...WITH VALUES DIMINISHING TOWARD THE
MERRIMACK VALLEY.
INSTABILITY IS MARGINAL...BUT ENOUGH WHERE CANNOT COMPLETELY RULE
OUT THE POSSIBILITY FOR ISOLATED THUNDERSTORMS. AREAS TOWARD THE
SOUTH COAST AND THE ADJACENT COASTAL WATERS WOULD BE MOST LIKELY
TO GET THESE THUNDERSTORMS...SHOULD THEY DEVELOP AT ALL.
PRECIPITABLE WATER VALUES REMAIN HIGH...SO LOCALLY HEAVY DOWNPOURS
REMAIN POSSIBLE AS WELL.
SUNDAY AND SUNDAY NIGHT...
PARENT LOW PRESSURE MOVES NORTH FROM UPSTATE NY...WHILE A
SECONDARY LOW PRESSURE CREATES AN OCCLUSION OVER OUR REGION. BOTH
OF THESE SYSTEMS SHOULD BE AWAY FROM OUR REGION TOWARD DAYBREAK
MONDAY MORNING. THIS SECONDARY LOW SHOULD PROVIDE A GOOD FOCUS
MECHANISM FOR THE AVAILABLE MOISTURE...ESPECIALLY BETWEEN IT AND
THE SURFACE LOW OVER UPSTATE NY. WILL CONTINUE WITH LIKELY POPS
SUNDAY INTO SUNDAY NIGHT. NOT THINKING IT WILL BE A TOTAL
WASHOUT...OR RAINING ALL THE TIME. INSTABILITY REMAINS MARGINAL...
SO WILL ONLY MENTION ISOLATED THUNDERSTORMS IN THE FORECAST.
SEASONABLE TEMPERATURES CONTINUE.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
HIGHLIGHTS...
* A FEW LINGERING SHOWERS ACROSS N CENTRAL AND W MA MONDAY...
OTHERWISE IMPROVING CONDITIONS
* HIGH PRESSURE EXPANDS ACROSS THE EASTERN U.S. TUESDAY THROUGH
FRIDAY WITH DRY CONDITIONS
* TEMPERATURES MAY RUN AROUND 10 DEGREES ABOVE SEASONAL NORMALS MID
TO LATE NEXT WEEK
OVERVIEW...
MEDIUM RANGE MODELS AND ENSEMBLES IN RATHER GOOD AGREEMENT
THROUGH MOST OF THIS FORECAST PERIOD...AND SHOWING GOOD
CONSISTENCY FOR THE LAST SEVERAL DAYS MAINLY FROM TUESDAY THROUGH
THE END OF NEXT WEEK.
MAY SEE SOME WIDELY SCT SHOWERS TRYING TO CLIP INTO N AND W MA
AND ACROSS THE BERKSHIRES DURING MONDAY AS THE UPPER LEVEL SYSTEM
AND SOUTHERN EDGE OF ITS COLD POOL TRAVERSES NORTHERN NEW ENGLAND
INTO THE MARITIMES. THIS LOOKS TO BE THE ONLY PRECIP THE REGION
WILL RECEIVE THIS UPCOMING WEEK AS THE RIDGE TAKES OVER AGAIN.
SIGNAL CONTINUES FOR LARGE HIGH PRES EXPANDING ACROSS THE EASTERN
SEABOARD...WITH HIGH AMPLITUDE H5 RIDGE RE-ESTABLISHING ACROSS
CENTRAL AND EASTERN CANADA. SOME QUESTION AS TO HOW THE SURFACE
HIGH SETS UP...AND WHETHER THERE WILL BE DAILY SEA BREEZES
DEVELOPING ESPECIALLY TUE AND/OR WED.
AS THE SURFACE RIDGE AXIS SHIFTS SLOWLY S TO THE MID ATLC STATES
BY THE MIDDLE OF NEXT WEEK...WILL SEE WINDS SHIFT TO S-SW. THIS
WILL BRING A RETURN OF WARM TEMPERATURES AND MODERATE HUMIDITY AS
DEWPTS RISE TO THE UPPER 50S TO MID 60S BY LATE NEXT WEEK. EXPECT
HIGHS TO RUN AROUND 10 DEGREES ABOVE SEASONAL NORMS FOR MID-LATE
SEPTEMBER... MAINLY IN THE LOWER-MID 80S AWAY FROM THE S COAST.
DETAILS...
MONDAY...MAY SEE WIDELY SCT SHOWERS ACROSS N CENTRAL AND W MA
DURING THE DAY DUE TO DIURNAL INFLUENCES ALONG WITH SOUTHERN EDGE
OF PASSING H5 SHORT WAVE/COLD POOL ACROSS N NEW ENGLAND. ANY
SHOWERS THAT DO DEVELOP SHOULD MELT AWAY QUICKLY AS THE SUN SETS.
SOME CLOUDS MAY LINGER INTO EARLY MON NIGHT...THEN WILL SEE MOSTLY
CLEAR CONDITIONS. EXPECT DAYTIME HIGHS RUNNING CLOSE TO OR JUST
BELOW SEASONAL NORMS.
TUESDAY-WEDNESDAY...HIGH PRES SETS UP FROM NY TO THE SE U.S. AS
LOW PRES ACROSS THE MARITIMES KEEPS SOME PRES GRADIENT ACROSS NEW
ENGLAND ESPECIALLY DURING TUESDAY. MAY SEE GUSTY W-NW WINDS DURING
TUE WHICH SHOULD DIMINISH TUE NIGHT AS THE HIGH EXTENDS INTO NEW
ENGLAND. WINDS SHIFT TO N ON WED...BUT WILL BE LIGHT WITH A WEAK
PRES GRADIENT SO SEA BREEZES SHOULD DEVELOP DURING THE LATE
MORNING AND AFTERNOON. EXPECT HIGHS BOTH DAYS IN THE UPPER 70S TO
LOWER 80S.
THURSDAY-FRIDAY...CONTINUED WARM AND DRY CONDITIONS AS HIGH PRES
RIDGE AXIS SHIFTS S. EXPECT WINDS TO SHIFT TO S-SW ON THU BUT
REMAIN LIGHT...THEN WILL PICK UP A BIT ON FRIDAY. TEMPS WILL TOP
OFF IN THE LOWER-MID 80S AWAY FROM THE S COAST WHERE ONSHORE WINDS
WILL KEEP IT JUST A TAD COOLER.
&&
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
TODAY...HIGH CONFIDENCE.
1025 AM UPDATE...AREA OF LOW CLOUDINESS/FOG FROM BOSTON TO
NORWOOD TO FITCHBURG HAS BEEN PIVOTING AND NOT MOVING. HOWEVER IT
IS SHOWING SIGNS OF ERODING FROM THE EAST. HRRR MODEL DEPICTS THIS
NICELY AND ACTUALLY SHIFTS THIS BAND OF LOW CLOUDS WESTWARD INTO
CENTRAL MA THIS AFTERNOON. LOW CLOUDS IN CT RIVER VALLEY AND
ACROSS NORTHERN CT AND WESTERN RI ARE ERODING BUT NEW CUMULUS
CLOUDS ARE ALREADY POPPING UP. THICK HIGH MID AND HIGH CLOUDINESS
CONTINUES TO PROGRESS STEADILY EASTWARD ACROSS PA/NY/NORTHERN NJ
AND WILL MOVE ACROSS WESTERN PORTIONS OF SOUTHERN NEW ENGLAND THIS
AFTERNOON. LIGHT WINDS ALLOWING SEA BREEZE DEVELOPMENT ALONG THE
COAST. SCATTERED SHOWERS LIKELY LATE...ESPECIALLY ACROSS FAR
WESTERN MA AND NORTHWEST CT.
AREAS OF MVFR CIGS BOS-OWD-FIT THROUGH 18Z OTHERWISE MAINLY VFR WITH
INCREASING MID LEVEL CLOUDINESS FROM W TO E THIS AFTERNOON.
TONIGHT...HIGH CONFIDENCE IN TRENDS. MODERATE CONFIDENCE IN
TIMING.
SHOWERS MOVE IN FROM WEST TO EAST WITH LOWERING CIGS AND VSBYS.
AFTER MIDNIGHT EXPECTING MOSTLY MVFR CIGS/VSBYS WITH IFR CIGS
ALONG THE SOUTH COAST. COULD BE AN ISOLATED THUNDERSTORM.
SUNDAY INTO SUNDAY NIGHT...MODERATE CONFIDENCE.
MVFR-LIFR CIGS WITH GUSTY E/SE-WINDS. SHOWERS. VSBY IMPACTS WITH
LIKELY IFR IN +SHRA. LOW CONFIDENCE TSRA. WITH ANY SHOWERS...
COULD SEE GUSTS IN EXCESS OF 20 KTS. MAY ALSO CONTEND WITH LLWS
IMPACTS...ESPECIALLY TOWARDS THE LATTER HALF OF SUNDAY INTO
EVENING PRIOR TO WINDS AT THE SURFACE BACKING OUT OF THE W. PATCHY
FOG POSSIBLE...WITH HIGHER CONFIDENCE TOWARDS THE SOUTH COAST.
KBOS TERMINAL...HIGH CONFIDENCE. SEA BREEZE DEVELOPING AROUND 16Z.
KBDL TERMINAL...MODERATE CONFIDENCE WITH TIMING. IFR VSBYS AND
CIGS E END OF AIRPORT WILL DISSIPATE AROUND 16Z...THEN BECOMING
VFR. MVFR CIGS AGAIN AFTER 00Z WITH MVFR/IFR VSBYS.
OUTLOOK /MONDAY THROUGH WEDNESDAY/...
MONDAY...MODERATE CONFIDENCE.
MAINLY VFR. MAY SEE BRIEF MVFR CONDITIONS IN ANY SHOWERS ACROSS N
CENTRAL AND W MA DURING THE LATE MORNING INTO THE EVENING. MAY
ALSO SEE BRIEF PATCHY FOG WITH LOCAL MVFR VSBYS LATE MON NIGHT
ACROSS E SLOPES OF THE BERKSHIRES. W WINDS GUSTING TO AROUND 20
KT DURING THE DAY ALONG THE COAST AS WELL AS THE HIGHER INLAND
TERRAIN.
TUESDAY AND WEDNESDAY...MODERATE CONFIDENCE.
MAINLY VFR WITH LIGHT WINDS. MAY SEE PATCHY LATE NIGHT FOG WITH
LOCAL MVFR-IFR CONDITIONS ACROSS NORMALLY PRONE INLAND AREAS AS
WELL AS ACROSS CAPE COD AND THE ISLANDS.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...HIGH CONFIDENCE.
THIS AFTERNOON...LIGHT WINDS SHIFTING FROM NORTH/NORTHWEST THIS
MORNING TO SOUTHEAST LATE THIS AFTERNOON. SEAS WILL REMAIN BELOW
5 FEET.
TONIGHT...SOUTHEAST WINDS AHEAD OF LOW PRESSURE APPROACHING FROM
PA. THESE WINDS SHOULD REMAIN AT OR BELOW 20 KNOTS. SEAS WILL
ALSO REMAIN BELOW 5 FEET. SHOWERS AHEAD OF THIS LOW PRESSURE WILL
SPREAD ACROSS THE WATERS FROM SOUTHWEST TO NORTHEAST...AND MAY
BRING REDUCED VSBYS OVERNIGHT.
SUNDAY INTO SUNDAY NIGHT...MODERATE CONFIDENCE.
PERIODIC SHOWERS. BREEZY E-SE WINDS INITIALLY. REDUCED
VISIBILITIES AT TIMES IN HEAVIER SHOWERS. GUSTS IN EXCESS OF 25
KTS POSSIBLE. WAVES BUILDING IN EXCESS OF 5 FEET OVER THE COASTAL
WATERS SOUTH OF NEW ENGLAND SUNDAY NIGHT.
OUTLOOK /MONDAY THROUGH WEDNESDAY/...
MONDAY...MODERATE CONFIDENCE.
W-NW WINDS GUSTING TO 25 KT ON THE OUTER WATERS SO SMALL CRAFTS
LOOK TO CONTINUE INTO MON NIGHT. SEAS BUILD UP TO 5-7 FT AS WELL.
WINDS AND SEAS SHOULD DIMINISH OVERNIGHT. MAY SEE SOME VSBY
RESTRICTIONS IN PATCHY LATE NIGHT FOG.
ODAY
TUESDAY AND WEDNESDAY...MODERATE CONFIDENCE.
W-NW WINDS CONTINUE ON TUE WITH GUSTS UP TO 20 KT...BUT EXPECTED
TO DIMINISH AS HIGH PRESSURE APPROACHES. EXPECT LIGHT WINDS TUE
NIGHT AND WED. SEAS 4 FT OR LESS THROUGH THIS PERIOD.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
RI...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...BELK/EVT/GAF
NEAR TERM...BELK/GAF
SHORT TERM...BELK
LONG TERM...EVT
AVIATION...BELK/EVT/GAF
MARINE...BELK/EVT/GAF
AREA FORECAST DISCUSSION
NWS TAUNTON MA
1039 AM EDT SAT SEP 12 2015
.SYNOPSIS...
WEAK HIGH PRESSURE WILL BRING DRY AND MILD CONDITIONS THROUGH
MOST OF THIS AFTENROON BUT SHOWERS WILL RETURN LATE THIS
AFTERNOON AND ESPECIALLY TONIGHT. SUNDAY WILL BE WET WITH THE
POSSIBILITY OF SOME THUNDERSTORMS ALONG WITH GUSTY WINDS. WHILE A
LIGHT TO MODERATE RAIN IS FORECAST...CAN NOT RULE OUT IT BEING
HEAVY AT TIMES. HIGH PRESSURE BUILDS EAST ACROSS THE MID ATLC
STATES EARLY NEXT WEEK. THIS RIDGE WILL EXPAND ALONG THE EASTERN
SEABOARD... DOMINATING THROUGH MOST OF NEXT WEEK WITH DRY
CONDITIONS. EXPECT TEMPERATURES TO WARM DURING THE
WEEK...ESPECIALLY FROM WEDNESDAY THROUGH FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
1025 AM UPDATE...
CLOUD TRENDS... AREA OF LOW CLOUDINESS/FOG FROM BOSTON TO NORWOOD
TO FITCHBURG HAS BEEN PIVOTING AND NOT MOVING. HOWEVER IT IS
SHOWING SIGNS OF ERODING FROM THE EAST. HRRR MODEL DEPICTS THIS
NICELY AND ACTUALLY SHIFTS THIS BAND OF LOW CLOUDS WESTWARD INTO
CENTRAL MA THIS AFTERNOON. LOW CLOUDS IN CT RIVER VALLEY AND
ACROSS NORTHERN CT AND WESTERN RI ARE ERODING BUT NEW CUMULUS
CLOUDS ARE ALREADY POPPING UP. THICK HIGH MID AND HIGH CLOUDINESS
CONTINUES TO PROGRESS STEADILY EASTWARD ACROSS PA/NY/NORTHERN NJ
AND WILL MOVE ACROSS WESTERN PORTIONS OF SOUTHERN NEW ENGLAND THIS
AFTERNOON. ADJUSTED GRIDS FOR CURRENT TRENDS.
PRECIPITATION TRENDS...BAND OF SHOWERS SOUTH OF LONG ISLAND HAS
DISSIPATED. SHOWERS ASSOCIATED WITH THE CLOUDINESS MENTIONED ABOVE
WAS MOVING EASTWARD ACROSS NORTHEAST PA AND CENTRAL NY STATE. OUR
SHOWER CHANCES WILL INCREASE IN WESTERN SECTIONS THIS AFTERNOON
AS IT PROGRESSES INTO WESTERN NEW ENGLAND. COULD ALSO SEE A FEW
SHOWERS POP UP FARTHER TO THE EAST IN EASTERN CT/CENTRAL MA/NORTHERN
RI LATER THIS AFTERNOON. NO ADJUSTMENTS MADE TO FORECAST POPS.
LIGHT PRESSURE GRADIENT WILL ALLOW FOR SEA BREEZES LATE THIS
INTO THE EARLY AFTERNOON. TEMPERATURES HAVE CLIMBED TO LOWER 70S
ALONG THE SOUTH COAST AND ISLANDS...SO RAISED MAXES THERE BY A
COUPLE OF DEGREES.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/...
TONIGHT...LOW LEVEL SOUTHEAST WINDS DEVELOP AND STRENGTHEN THROUGH
THE NIGHT AS A LOW APPROACHES. RATHER GOOD AGREEMENT IN THE 12/00Z
GUIDANCE THAT A WARM FRONT WILL REACH THE SOUTH COAST OF NEW
ENGLAND AROUND MIDNIGHT SUNDAY. THIS FRONT SLOWLY MOVES NORTH INTO
OUR REGION LATE. THIS FRONT WILL BE THE FOCUS FOR SHOWERS.
GREATEST CHANCE FOR SHOWERS WOULD BE NEAREST THE FRONT ACROSS
AREAS SOUTH OF THE MASS PIKE...WITH VALUES DIMINISHING TOWARD THE
MERRIMACK VALLEY.
INSTABILITY IS MARGINAL...BUT ENOUGH WHERE CANNOT COMPLETELY RULE
OUT THE POSSIBILITY FOR ISOLATED THUNDERSTORMS. AREAS TOWARD THE
SOUTH COAST AND THE ADJACENT COASTAL WATERS WOULD BE MOST LIKELY
TO GET THESE THUNDERSTORMS...SHOULD THEY DEVELOP AT ALL.
PRECIPITABLE WATER VALUES REMAIN HIGH...SO LOCALLY HEAVY DOWNPOURS
REMAIN POSSIBLE AS WELL.
SUNDAY AND SUNDAY NIGHT...
PARENT LOW PRESSURE MOVES NORTH FROM UPSTATE NY...WHILE A
SECONDARY LOW PRESSURE CREATES AN OCCLUSION OVER OUR REGION. BOTH
OF THESE SYSTEMS SHOULD BE AWAY FROM OUR REGION TOWARD DAYBREAK
MONDAY MORNING. THIS SECONDARY LOW SHOULD PROVIDE A GOOD FOCUS
MECHANISM FOR THE AVAILABLE MOISTURE...ESPECIALLY BETWEEN IT AND
THE SURFACE LOW OVER UPSTATE NY. WILL CONTINUE WITH LIKELY POPS
SUNDAY INTO SUNDAY NIGHT. NOT THINKING IT WILL BE A TOTAL
WASHOUT...OR RAINING ALL THE TIME. INSTABILITY REMAINS MARGINAL...
SO WILL ONLY MENTION ISOLATED THUNDERSTORMS IN THE FORECAST.
SEASONABLE TEMPERATURES CONTINUE.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
HIGHLIGHTS...
* A FEW LINGERING SHOWERS ACROSS N CENTRAL AND W MA MONDAY...
OTHERWISE IMPROVING CONDITIONS
* HIGH PRESSURE EXPANDS ACROSS THE EASTERN U.S. TUESDAY THROUGH
FRIDAY WITH DRY CONDITIONS
* TEMPERATURES MAY RUN AROUND 10 DEGREES ABOVE SEASONAL NORMALS MID
TO LATE NEXT WEEK
OVERVIEW...
MEDIUM RANGE MODELS AND ENSEMBLES IN RATHER GOOD AGREEMENT
THROUGH MOST OF THIS FORECAST PERIOD...AND SHOWING GOOD
CONSISTENCY FOR THE LAST SEVERAL DAYS MAINLY FROM TUESDAY THROUGH
THE END OF NEXT WEEK.
MAY SEE SOME WIDELY SCT SHOWERS TRYING TO CLIP INTO N AND W MA
AND ACROSS THE BERKSHIRES DURING MONDAY AS THE UPPER LEVEL SYSTEM
AND SOUTHERN EDGE OF ITS COLD POOL TRAVERSES NORTHERN NEW ENGLAND
INTO THE MARITIMES. THIS LOOKS TO BE THE ONLY PRECIP THE REGION
WILL RECEIVE THIS UPCOMING WEEK AS THE RIDGE TAKES OVER AGAIN.
SIGNAL CONTINUES FOR LARGE HIGH PRES EXPANDING ACROSS THE EASTERN
SEABOARD...WITH HIGH AMPLITUDE H5 RIDGE RE-ESTABLISHING ACROSS
CENTRAL AND EASTERN CANADA. SOME QUESTION AS TO HOW THE SURFACE
HIGH SETS UP...AND WHETHER THERE WILL BE DAILY SEA BREEZES
DEVELOPING ESPECIALLY TUE AND/OR WED.
AS THE SURFACE RIDGE AXIS SHIFTS SLOWLY S TO THE MID ATLC STATES
BY THE MIDDLE OF NEXT WEEK...WILL SEE WINDS SHIFT TO S-SW. THIS
WILL BRING A RETURN OF WARM TEMPERATURES AND MODERATE HUMIDITY AS
DEWPTS RISE TO THE UPPER 50S TO MID 60S BY LATE NEXT WEEK. EXPECT
HIGHS TO RUN AROUND 10 DEGREES ABOVE SEASONAL NORMS FOR MID-LATE
SEPTEMBER... MAINLY IN THE LOWER-MID 80S AWAY FROM THE S COAST.
DETAILS...
MONDAY...MAY SEE WIDELY SCT SHOWERS ACROSS N CENTRAL AND W MA
DURING THE DAY DUE TO DIURNAL INFLUENCES ALONG WITH SOUTHERN EDGE
OF PASSING H5 SHORT WAVE/COLD POOL ACROSS N NEW ENGLAND. ANY
SHOWERS THAT DO DEVELOP SHOULD MELT AWAY QUICKLY AS THE SUN SETS.
SOME CLOUDS MAY LINGER INTO EARLY MON NIGHT...THEN WILL SEE MOSTLY
CLEAR CONDITIONS. EXPECT DAYTIME HIGHS RUNNING CLOSE TO OR JUST
BELOW SEASONAL NORMS.
TUESDAY-WEDNESDAY...HIGH PRES SETS UP FROM NY TO THE SE U.S. AS
LOW PRES ACROSS THE MARITIMES KEEPS SOME PRES GRADIENT ACROSS NEW
ENGLAND ESPECIALLY DURING TUESDAY. MAY SEE GUSTY W-NW WINDS DURING
TUE WHICH SHOULD DIMINISH TUE NIGHT AS THE HIGH EXTENDS INTO NEW
ENGLAND. WINDS SHIFT TO N ON WED...BUT WILL BE LIGHT WITH A WEAK
PRES GRADIENT SO SEA BREEZES SHOULD DEVELOP DURING THE LATE
MORNING AND AFTERNOON. EXPECT HIGHS BOTH DAYS IN THE UPPER 70S TO
LOWER 80S.
THURSDAY-FRIDAY...CONTINUED WARM AND DRY CONDITIONS AS HIGH PRES
RIDGE AXIS SHIFTS S. EXPECT WINDS TO SHIFT TO S-SW ON THU BUT
REMAIN LIGHT...THEN WILL PICK UP A BIT ON FRIDAY. TEMPS WILL TOP
OFF IN THE LOWER-MID 80S AWAY FROM THE S COAST WHERE ONSHORE WINDS
WILL KEEP IT JUST A TAD COOLER.
&&
.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
TODAY...HIGH CONFIDENCE.
1025 AM UPDATE...AREA OF LOW CLOUDINESS/FOG FROM BOSTON TO
NORWOOD TO FITCHBURG HAS BEEN PIVOTING AND NOT MOVING. HOWEVER IT
IS SHOWING SIGNS OF ERODING FROM THE EAST. HRRR MODEL DEPICTS THIS
NICELY AND ACTUALLY SHIFTS THIS BAND OF LOW CLOUDS WESTWARD INTO
CENTRAL MA THIS AFTERNOON. LOW CLOUDS IN CT RIVER VALLEY AND
ACROSS NORTHERN CT AND WESTERN RI ARE ERODING BUT NEW CUMULUS
CLOUDS ARE ALREADY POPPING UP. THICK HIGH MID AND HIGH CLOUDINESS
CONTINUES TO PROGRESS STEADILY EASTWARD ACROSS PA/NY/NORTHERN NJ
AND WILL MOVE ACROSS WESTERN PORTIONS OF SOUTHERN NEW ENGLAND THIS
AFTERNOON. LIGHT WINDS ALLOWING SEA BREEZE DEVELOPMENT ALONG THE
COAST. SCATTERED SHOWERS LIKELY LATE...ESPECIALLY ACROSS FAR
WESTERN MA AND NORTHWEST CT.
AREAS OF MVFR CIGS BOS-OWD-FIT THROUGH 18Z OTHERWISE MAINLY VFR WITH
INCREASING MID LEVEL CLOUDINESS FROM W TO E THIS AFTERNOON.
TONIGHT...HIGH CONFIDENCE IN TRENDS. MODERATE CONFIDENCE IN
TIMING.
SHOWERS MOVE IN FROM WEST TO EAST WITH LOWERING CIGS AND VSBYS.
AFTER MIDNIGHT EXPECTING MOSTLY MVFR CIGS/VSBYS WITH IFR CIGS
ALONG THE SOUTH COAST. COULD BE AN ISOLATED THUNDERSTORM.
SUNDAY INTO SUNDAY NIGHT...MODERATE CONFIDENCE.
MVFR-LIFR CIGS WITH GUSTY E/SE-WINDS. SHOWERS. VSBY IMPACTS WITH
LIKELY IFR IN +SHRA. LOW CONFIDENCE TSRA. WITH ANY SHOWERS...
COULD SEE GUSTS IN EXCESS OF 20 KTS. MAY ALSO CONTEND WITH LLWS
IMPACTS...ESPECIALLY TOWARDS THE LATTER HALF OF SUNDAY INTO
EVENING PRIOR TO WINDS AT THE SURFACE BACKING OUT OF THE W. PATCHY
FOG POSSIBLE...WITH HIGHER CONFIDENCE TOWARDS THE SOUTH COAST.
KBOS TERMINAL...HIGH CONFIDENCE. SEA BREEZE DEVELOPING AROUND 16Z.
KBDL TERMINAL...MODERATE CONFIDENCE WITH TIMING. IFR VSBYS AND
CIGS E END OF AIRPORT WILL DISSIPATE AROUND 16Z...THEN BECOMING
VFR. MVFR CIGS AGAIN AFTER 00Z WITH MVFR/IFR VSBYS.
OUTLOOK /MONDAY THROUGH WEDNESDAY/...
MONDAY...MODERATE CONFIDENCE.
MAINLY VFR. MAY SEE BRIEF MVFR CONDITIONS IN ANY SHOWERS ACROSS N
CENTRAL AND W MA DURING THE LATE MORNING INTO THE EVENING. MAY
ALSO SEE BRIEF PATCHY FOG WITH LOCAL MVFR VSBYS LATE MON NIGHT
ACROSS E SLOPES OF THE BERKSHIRES. W WINDS GUSTING TO AROUND 20
KT DURING THE DAY ALONG THE COAST AS WELL AS THE HIGHER INLAND
TERRAIN.
TUESDAY AND WEDNESDAY...MODERATE CONFIDENCE.
MAINLY VFR WITH LIGHT WINDS. MAY SEE PATCHY LATE NIGHT FOG WITH
LOCAL MVFR-IFR CONDITIONS ACROSS NORMALLY PRONE INLAND AREAS AS
WELL AS ACROSS CAPE COD AND THE ISLANDS.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...HIGH CONFIDENCE.
THIS AFTERNOON...LIGHT WINDS SHIFTING FROM NORTH/NORTHWEST THIS
MORNING TO SOUTHEAST LATE THIS AFTERNOON. SEAS WILL REMAIN BELOW
5 FEET.
TONIGHT...SOUTHEAST WINDS AHEAD OF LOW PRESSURE APPROACHING FROM
PA. THESE WINDS SHOULD REMAIN AT OR BELOW 20 KNOTS. SEAS WILL
ALSO REMAIN BELOW 5 FEET. SHOWERS AHEAD OF THIS LOW PRESSURE WILL
SPREAD ACROSS THE WATERS FROM SOUTHWEST TO NORTHEAST...AND MAY
BRING REDUCED VSBYS OVERNIGHT.
SUNDAY INTO SUNDAY NIGHT...MODERATE CONFIDENCE.
PERIODIC SHOWERS. BREEZY E-SE WINDS INITIALLY. REDUCED
VISIBILITIES AT TIMES IN HEAVIER SHOWERS. GUSTS IN EXCESS OF 25
KTS POSSIBLE. WAVES BUILDING IN EXCESS OF 5 FEET OVER THE COASTAL
WATERS SOUTH OF NEW ENGLAND SUNDAY NIGHT.
OUTLOOK /MONDAY THROUGH WEDNESDAY/...
MONDAY...MODERATE CONFIDENCE.
W-NW WINDS GUSTING TO 25 KT ON THE OUTER WATERS SO SMALL CRAFTS
LOOK TO CONTINUE INTO MON NIGHT. SEAS BUILD UP TO 5-7 FT AS WELL.
WINDS AND SEAS SHOULD DIMINISH OVERNIGHT. MAY SEE SOME VSBY
RESTRICTIONS IN PATCHY LATE NIGHT FOG.
ODAY
TUESDAY AND WEDNESDAY...MODERATE CONFIDENCE.
W-NW WINDS CONTINUE ON TUE WITH GUSTS UP TO 20 KT...BUT EXPECTED
TO DIMINISH AS HIGH PRESSURE APPROACHES. EXPECT LIGHT WINDS TUE
NIGHT AND WED. SEAS 4 FT OR LESS THROUGH THIS PERIOD.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
RI...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...BELK/EVT/GAF
NEAR TERM...BELK/GAF
SHORT TERM...BELK
LONG TERM...EVT
AVIATION...BELK/EVT/GAF
MARINE...BELK/EVT/GAF
EAST CENTRAL FLORIDA FORECAST DISCUSSION
NWS MELBOURNE FL
918 AM EDT SAT SEP 12 2015
.DISCUSSION... EARLY STORMS ONGOING SINCE THE PRE-DAWN HOURS OVER
THE EASTERN GULF CONTINUE TO DEVELOP TOWARD THE SOUTH AND EAST ALONG
THE WEST CST OF FL. SCT LIGHT SHOWERS...REMNANTS OF THIS EARLY
ACTIVITY WILL SPREAD ACROSS THE I-4 CORRIDOR OVER THE NEXT COUPLE OF
HOURS BRINGING SOME LIGHT RAIN TO KISSIMMEE AND TITUSVILLE
NORTHWARD.
FURTHER DESTABILIZATION OF THE LOCAL AIRMASS BY LIMITED SB HEATING
COUPLED WITH FORCED ASCENT AS THE UNSEASONABLY STRONG UPR WAVE
APPROACHES THE REGION SHOULD INCREASE THE LIKELIHOOD OF STORMS THIS
AFTERNOON. THE TIMING AND PLACEMENT OF STORM DEVELOPMENT IS
COMPLICATED BY CLOUD COVER AND THE LATER DIURNAL TIMING OF THE
APPROACHING DISTURBANCE. THE BEST FORCED ASCENT NECESSARY FOR ANY
STRONGER STORMS WL EXIST ROUGHLY ALONG AND NORTH OF THE I-4
CORRIDOR...WHEREAS THE BEST SB INSTABILITY WILL EXIST SOUTH OF THAT
AREA WHERE LOWER CLOUD COVER IS IN PLACE. LTST HRRR GUID INDICATES
DEVELOPMENT SCT STORMS MOVING INTO ECFL UNIFORMLY FROM THE WEST FROM
AROUND 2PM THROUGH DUSK. NOT SURE IF THE MAIN SIGNAL IS A DIURNAL
ONE OR IF IS DIRECTLY ASCD WITH THE APCHG DISTURBANCE. EXISTING WIND
FIELDS ALOFT WL INCREASE...THUS LEADING TO A SPC ADVERTISED SLIGHT
RISK OF DMG WINDS IN SOME OF THE STRONG TO ISOLD SEVERE STORMS...
MAINLY FROM LAKE KISSIMMEE TO COCOA NORTHWARD. A THREAT OF LOCALLY
STRONG STORMS WILL EXIST AREAWIDE AS WELL FROM MID TO LATE
AFTERNOON.
WILL MAKE A FEW MINOR ADJUSTMENTS TO POP AND WX GRIDS FOR THE SHORT
TERM.
&&
.AVIATION...EXPECT A STEADY INCREASE IN PCPN AND STORM COVERAGE FROM
THE WEST THROUGH THE AFTERNOON. FORECASTS WILL LIKELY NEED
AMENDMENTS GIVEN THE EXPECTED EVOLUTION AND INHERENT UNCERTAINTIES
OF AFTERNOON CONVECTION. WINDS WILL STEADILY INCREASE THROUGH EARLY
AFTERNOON. SEA BREEZE WILL LIKELY DEVELOP VRB SWD...BUT REMAINED
CLOSE TO THE COAST.
&&
.MARINE...(PREV DISC) SOUTHWEST FLOW CONTINUES AND WILL LIKELY
STRENGTHEN THIS AFTERNOON...UP TO 15 TO 20 KNOTS WITH OCCASIONAL
HIGHER GUSTS MAINLY OVER THE OPEN OUTER WATERS. GIVEN THE OFFSHORE
FLOW AND LIMITED FETCH...SEAS EXPECTED TO REMAIN BETWEEN 2 TO 3
FEET...UP TO 4 FEET WELL OFFSHORE. PRIMARY WEATHER HAZARD REMAINS
LOCALLY HIGHER WINDS AND SEAS ASSOCIATED WITH FAST MOVING SHOWERS
AND STORMS FROM THE MAINLAND. MARINERS SHOULD FOLLOW THE LATEST
OUTLOOKS AS THIS PATTERN WILL FAVOR THE ISSUANCE OF MARINE WARNINGS.
&&
$$
JP/RW
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
753 AM EDT SAT SEP 12 2015
.SYNOPSIS...
AN APPROACHING COLD FRONT WILL MOVE THROUGH THE FORECAST AREA THIS
EVENING. DRY AND COOLER HIGH PRESSURE WILL DOMINATE BEHIND THE
FRONT SUNDAY THROUGH WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
THE APPROACHING COLD FRONT WILL MOVE THROUGH THE FORECAST AREA
THIS EVENING. THE HRRR DISPLAYS NUMEROUS SHOWERS AHEAD OF THE
FRONT MAINLY IN THE EAST PART ASSOCIATED WITH AN H85 JET TODAY.
CONVERGENCE NEAR THE FRONT AND COOLING ASSOCIATED WITH THE UPPER
TROUGH SUPPORTS A CONTINUED SHOWER CHANCE INTO THE EVENING.
THUNDERSTORMS MAY ALSO OCCUR. THE MODELS SHOW SIGNIFICANT SHEAR
WITH H85 WINDS 30 TO 35 KNOTS IN THE EAST PART. HOWEVER...THE
SHEAR APPEARS GREATEST EARLY TODAY AND CLOUDINESS SHOULD LIMIT
INSTABILITY. THE NAM DISPLAYS WEAK INSTABILITY WITH SURFACE-BASED
LI/S AROUND -3. THE SEVERE THUNDERSTORM CHANCE IS LOW. DRYING WILL
OCCUR LATE TONIGHT BEHIND THE FRONT. USED THE GUIDANCE CONSENSUS
FOR THE TEMPERATURE FORECAST TODAY. MIXING ASSOCIATED WITH THE
FRONT FAVORS THE WARMER GUIDANCE TEMPERATURES TONIGHT.
&&
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
THE DRY AIR MASS MOVING INTO THE FORECAST AREA WILL DOMINATE
SUNDAY AND SUNDAY NIGHT. THE TEMPERATURE GUIDANCE WAS CLOSE WITH
HIGHS SUNDAY MAINLY IN THE LOWER 80S AND LOWS SUNDAY NIGHT IN THE
LOWER AND MIDDLE 50S. THESE LOW TEMPERATURES WILL BE THE COOLEST
WE HAVE EXPERIENCED SINCE MAY.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
THE GFS AND ECMWF DISPLAY HIGH PRESSURE CENTERED NEAR THE
FORECAST AREA MONDAY. THE MODELS HAVE RIDGING IN THE ATLANTIC
WITH A LONG-FETCH EASTERLY FLOW INTO THE FORECAST AREA DURING THE
REST OF THE MEDIUM-RANGE PERIOD. THE MODELS SHOW UPPER RIDGING
EARLY BUT WEAK TROUGHING DURING THE REST OF THE PERIOD. THE ECMWF
WAS MORE PROGRESSIVE SHIFTING DEEPER MOISTURE INTO THE FORECAST
AREA FROM THE SOUTH WEDNESDAY. USED AN AVERAGE OF THE GFS AND
ECMWF MOS FOR THE POP FORECAST. THE MOS INDICATES BELOW NORMAL
TEMPERATURES MONDAY WITH NEAR NORMAL TEMPERATURES DURING THE REST
OF THE PERIOD.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
WIDESPREAD LIGHT SHOWERS AFFECTING AGS/DNL/OGB THIS MORNING WITH
SCATTERED SHOWERS AFFECTING CAE/CUB. MVFR CIGS THIS
MORNING...LIFTING TO VFR BY MIDDAY. EXPECT SHOWERS TO PERSIST
THROUGH THE AFTERNOON. POTENTIAL FOR THUNDERSTORMS REMAINS TOO LOW
TO INCLUDE ATTM. WINDS WILL BE SOUTHWESTERLY WITH GUSTS UP TO 20
MPH BETWEEN 14Z AND 13/00Z. A COLD FRONT WILL CROSS THE TAF SITES
13/02Z-13/05Z WITH CONVECTION ENDING AND WINDS SHIFTING NORTHWEST.
EXTENDED AVIATION OUTLOOK... NO SIGNIFICANT IMPACTS TO AVIATION
EXPECTED SUNDAY THROUGH WEDNESDAY.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
629 AM EDT SAT SEP 12 2015
.SYNOPSIS...
AN APPROACHING COLD FRONT WILL MOVE THROUGH THE FORECAST AREA THIS
EVENING. DRY AND COOLER HIGH PRESSURE WILL DOMINATE BEHIND THE
FRONT SUNDAY THROUGH WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
THE APPROACHING COLD FRONT WILL MOVE THROUGH THE FORECAST AREA
THIS EVENING. THE HRRR DISPLAYS NUMEROUS SHOWERS AHEAD OF THE
FRONT MAINLY IN THE EAST PART ASSOCIATED WITH AN H85 JET TODAY.
CONVERGENCE NEAR THE FRONT AND COOLING ASSOCIATED WITH THE UPPER
TROUGH SUPPORTS A CONTINUED SHOWER CHANCE INTO THE EVENING.
THUNDERSTORMS MAY ALSO OCCUR. THE MODELS SHOW SIGNIFICANT SHEAR
WITH H85 WINDS 30 TO 35 KNOTS IN THE EAST PART. HOWEVER...THE
SHEAR APPEARS GREATEST EARLY TODAY AND CLOUDINESS SHOULD LIMIT
INSTABILITY. THE NAM DISPLAYS WEAK INSTABILITY WITH SURFACE-BASED
LI/S AROUND -3. THE SEVERE THUNDERSTORM CHANCE IS LOW. DRYING WILL
OCCUR LATE TONIGHT BEHIND THE FRONT. USED THE GUIDANCE CONSENSUS
FOR THE TEMPERATURE FORECAST TODAY. MIXING ASSOCIATED WITH THE
FRONT FAVORS THE WARMER GUIDANCE TEMPERATURES TONIGHT.
&&
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
THE DRY AIR MASS MOVING INTO THE FORECAST AREA WILL DOMINATE
SUNDAY AND SUNDAY NIGHT. THE TEMPERATURE GUIDANCE WAS CLOSE WITH
HIGHS SUNDAY MAINLY IN THE LOWER 80S AND LOWS SUNDAY NIGHT IN THE
LOWER AND MIDDLE 50S. THESE LOW TEMPERATURES WILL BE THE COOLEST
WE HAVE EXPERIENCED SINCE MAY.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
THE GFS AND ECMWF DISPLAY HIGH PRESSURE CENTERED NEAR THE
FORECAST AREA MONDAY. THE MODELS HAVE RIDGING IN THE ATLANTIC
WITH A LONG-FETCH EASTERLY FLOW INTO THE FORECAST AREA DURING THE
REST OF THE MEDIUM-RANGE PERIOD. THE MODELS SHOW UPPER RIDGING
EARLY BUT WEAK TROUGHING DURING THE REST OF THE PERIOD. THE ECMWF
WAS MORE PROGRESSIVE SHIFTING DEEPER MOISTURE INTO THE FORECAST
AREA FROM THE SOUTH WEDNESDAY. USED AN AVERAGE OF THE GFS AND
ECMWF MOS FOR THE POP FORECAST. THE MOS INDICATES BELOW NORMAL
TEMPERATURES MONDAY WITH NEAR NORMAL TEMPERATURES DURING THE REST
OF THE PERIOD.
&&
.AVIATION /10Z SATURDAY THROUGH WEDNESDAY/...
VFR CONDITIONS EXPECTED THROUGH MUCH OF THE PERIOD...WITH BRIEF
MVFR IN SHOWERS AND THUNDERSTORMS.
SHOWERS HAVE BEGUN TO MOVE INTO THE AREA WITH MOST OF THE RAIN
CURRENTLY MOVING TOWARD AGS/DNL/OGB. EXPECT SHOWERS TO ENTER THE
TAF SITES OVER THE NEXT COUPLE OF HOURS AND PERSIST THROUGH THE
AFTERNOON HOURS. HAVE UPDATE THE TAFS TO INCLUDE MENTION OF THE
SHOWERS. POTENTIAL FOR THUNDERSTORMS REMAINS TOO LOW TO INCLUDE
ATTM. WINDS WILL BE SOUTHWESTERLY THROUGH THE PERIOD WITH GUSTS UP
TO 20 MPH BETWEEN 14Z AND 13/00Z.
EXTENDED AVIATION OUTLOOK... NO SIGNIFICANT IMPACTS TO AVIATION
EXPECTED SUNDAY THROUGH WEDNESDAY.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
99
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1018 AM EDT SAT SEP 12 2015
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 254 AM EDT SAT SEP 12 2015
AN UPPER LEVEL SYSTEM WILL BRING A CHANCE OF SHOWERS TO THE AREA
TODAY. HIGH PRESSURE WILL THEN BUILD IN AND BRING DRY AND WARMING
CONDITIONS THROUGH MID WEEK NEXT WEEK. A COLD FRONT WILL BRING
CHANCES FOR RAIN AGAIN LATE NEXT WEEK.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 1000 AM EDT SAT SEP 12 2015
UPPER LOW IN THE PROCESS OF CLOSING OFF OVER THE REGION THIS
MORNING WITH A MIX OF CLOUDS AND SUN. SHOWERS ASSOCIATED WITH THE
UPPER ENERGY CONTINUE TO DRIFT SOUTH OFF LAKE MICHIGAN BUT PRECIP
HAS LARGELY STAYED OUT OF THE FORECAST AREA SO FAR THIS MORNING.
TOUCH OF FALL IN THE AIR WITH 14Z TEMPS PRIMARILY IN THE 50S.
FORECAST IN VERY GOOD SHAPE WITH ONLY SUBTLE ADJUSTMENTS NEEDED
FOR THE REST OF THE DAY. COLD POOL ALOFT WILL SETTLE OVER CENTRAL
INDIANA TODAY AND COMBINED WITH THE FORCING ALOFT AND STEEPENING
LAPSE RATES...EXPECT CU TO FILL IN AND ISOLATED TO SCATTERED
SHOWERS DEVELOP INTO THE AFTERNOON. HRRR AND WRF GUIDANCE HAS NICE
HANDLE ON EXPECTATION OF CONVECTIVE DEVELOPMENT...WITH GREATEST
PRECIP COVERAGE MOVING SOUTH ACROSS THE FORECAST AREA WITH THE
UPPER ENERGY THROUGH THE COURSE OF THE AFTERNOON. INSTABILITY
REMAINS VERY WEAK AND LIKELY WILL NOT BE ENOUGH TO GENERATE ANY
LIGHTNING STRIKES.
MADE SOME MINOR ADJUSTMENTS TO TEMPS WITH HIGHS REMAINING
PRIMARILY IN THE LOWER AND MID 60S. GUSTS TO AROUND 20MPH THIS
AFTERNOON WILL GIVE AN EVEN COOLER FALL-LIKE FEEL. ZONE AND GRID
UPDATES OUT.
&&
.SHORT TERM.../TONIGHT THROUGH MONDAY NIGHT/
ISSUED AT 254 AM EDT SAT SEP 12 2015
FOCUS IS ON SKY COVER EARLY IN THE PERIOD. MODELS ARE CLOSE ENOUGH
TO USE A BLEND.
THE UPPER TROUGH WILL MOVE AWAY FROM CENTRAL INDIANA TONIGHT
ALLOWING SOME DECREASE IN CLOUDS. STILL LOOKS TO BE SOME CLOUDS OFF
OF LAKE MICHIGAN THOUGH...SO WENT PARTLY CLOUDY TONIGHT MOST AREAS.
AS WARMER AIR MOVES IN ALOFT SUNDAY ALONG WITH MORE SUBSIDENCE
/THANKS TO RISING HEIGHTS ALOFT AND HIGH PRESSURE MOVING IN AT THE
SURFACE/...CLOUDS WILL DECREASE.
WITH HIGH PRESSURE AROUND FOR THE REMAINDER OF THE SHORT
TERM...EXPECT MOSTLY CLEAR SKIES.
FOR LOW TEMPERATURES TONIGHT WENT WITH A BLEND OF RAW MODEL
TEMPERATURES AS THESE REFLECT THE HIGHER CLOUD COVER WELL. AFTERWARD
A BLEND OF MOS LOOKS GOOD.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
ISSUED AT 254 AM EDT SAT SEP 12 2015
MODELS ARE CLOSE ENOUGH THAT THE SUPERBLEND INITIALIZATION WAS
ACCEPTED FOR MOST ITEMS.
HIGH PRESSURE WILL KEEP DRY AND WARM CONDITIONS THROUGH WEDNESDAY
NIGHT. MODELS HAVE SLOWED ARRIVAL OF RAIN LATER IN THE WEEK...AND
THIS LOOKS REASONABLE WITH SOUTHWEST FLOW ALOFT KEEPING SYSTEMS TO
THE WEST. THUS REMOVED POPS FOR THURSDAY AND WENT DRY.
UPPER FLOW WILL GRADUALLY FLATTEN OUT LATE NEXT WEEK AND ALLOW A
COLD FRONT TO MOVE IN. WILL KEEP RAIN CHANCES THURSDAY NIGHT INTO
FRIDAY.
TEMPERATURES WILL BE ABOVE AVERAGE DURING THE LONG TERM.
&&
.AVIATION /DISCUSSION FOR THE 121500Z TAF ISSUANCE/...
ISSUED AT 1018 AM EDT SAT SEP 12 2015
OUTSIDE OF ANY SHOWERS TODAY...VFR EXPECTED THROUGH THE PERIOD.
CLOUDS WILL DEVELOP/INCREASE LATE THIS MORNING AS AN UPPER LEVEL
SYSTEM MOVES INTO THE AREA. SCATTERED SHOWERS WILL DEVELOP WITH THIS
FEATURE AS WELL...BUT RANDOM NATURE OF SHOWERS AND COVERAGE EXPECTED
WARRANT ONLY A VCSH MENTION AT THE TAF LOCATIONS. BRIEF MVFR
CONDITIONS ARE POSSIBLE IN ANY SHOWER.
SHOWERS WILL TAPER OFF LATE THIS AFTERNOON AND CEILINGS SHOULD
DISSIPATE BY EARLY EVENING...LEAVING BEHIND VFR CONDITIONS
OVERNIGHT. CANNOT ABSOLUTELY RULE OUT SOME PATCHY FOG LATE TONIGHT
BUT CONFIDENCE IS TOO LOW TO MENTION.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...50
NEAR TERM...RYAN
SHORT TERM...50
LONG TERM....50
AVIATION...50/CP
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1000 AM EDT SAT SEP 12 2015
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
ISSUED AT 254 AM EDT SAT SEP 12 2015
AN UPPER LEVEL SYSTEM WILL BRING A CHANCE OF SHOWERS TO THE AREA
TODAY. HIGH PRESSURE WILL THEN BUILD IN AND BRING DRY AND WARMING
CONDITIONS THROUGH MID WEEK NEXT WEEK. A COLD FRONT WILL BRING
CHANCES FOR RAIN AGAIN LATE NEXT WEEK.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 1000 AM EDT SAT SEP 12 2015
UPPER LOW IN THE PROCESS OF CLOSING OFF OVER THE REGION THIS
MORNING WITH A MIX OF CLOUDS AND SUN. SHOWERS ASSOCIATED WITH THE
UPPER ENERGY CONTINUE TO DRIFT SOUTH OFF LAKE MICHIGAN BUT PRECIP
HAS LARGELY STAYED OUT OF THE FORECAST AREA SO FAR THIS MORNING.
TOUCH OF FALL IN THE AIR WITH 14Z TEMPS PRIMARILY IN THE 50S.
FORECAST IN VERY GOOD SHAPE WITH ONLY SUBTLE ADJUSTMENTS NEEDED
FOR THE REST OF THE DAY. COLD POOL ALOFT WILL SETTLE OVER CENTRAL
INDIANA TODAY AND COMBINED WITH THE FORCING ALOFT AND STEEPENING
LAPSE RATES...EXPECT CU TO FILL IN AND ISOLATED TO SCATTERED
SHOWERS DEVELOP INTO THE AFTERNOON. HRRR AND WRF GUIDANCE HAS NICE
HANDLE ON EXPECTATION OF CONVECTIVE DEVELOPMENT...WITH GREATEST
PRECIP COVERAGE MOVING SOUTH ACROSS THE FORECAST AREA WITH THE
UPPER ENERGY THROUGH THE COURSE OF THE AFTERNOON. INSTABILITY
REMAINS VERY WEAK AND LIKELY WILL NOT BE ENOUGH TO GENERATE ANY
LIGHTNING STRIKES.
MADE SOME MINOR ADJUSTMENTS TO TEMPS WITH HIGHS REMAINING
PRIMARILY IN THE LOWER AND MID 60S. GUSTS TO AROUND 20MPH THIS
AFTERNOON WILL GIVE AN EVEN COOLER FALL-LIKE FEEL. ZONE AND GRID
UPDATES OUT.
&&
.SHORT TERM.../TONIGHT THROUGH MONDAY NIGHT/
ISSUED AT 254 AM EDT SAT SEP 12 2015
FOCUS IS ON SKY COVER EARLY IN THE PERIOD. MODELS ARE CLOSE ENOUGH
TO USE A BLEND.
THE UPPER TROUGH WILL MOVE AWAY FROM CENTRAL INDIANA TONIGHT
ALLOWING SOME DECREASE IN CLOUDS. STILL LOOKS TO BE SOME CLOUDS OFF
OF LAKE MICHIGAN THOUGH...SO WENT PARTLY CLOUDY TONIGHT MOST AREAS.
AS WARMER AIR MOVES IN ALOFT SUNDAY ALONG WITH MORE SUBSIDENCE
/THANKS TO RISING HEIGHTS ALOFT AND HIGH PRESSURE MOVING IN AT THE
SURFACE/...CLOUDS WILL DECREASE.
WITH HIGH PRESSURE AROUND FOR THE REMAINDER OF THE SHORT
TERM...EXPECT MOSTLY CLEAR SKIES.
FOR LOW TEMPERATURES TONIGHT WENT WITH A BLEND OF RAW MODEL
TEMPERATURES AS THESE REFLECT THE HIGHER CLOUD COVER WELL. AFTERWARD
A BLEND OF MOS LOOKS GOOD.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
ISSUED AT 254 AM EDT SAT SEP 12 2015
MODELS ARE CLOSE ENOUGH THAT THE SUPERBLEND INITIALIZATION WAS
ACCEPTED FOR MOST ITEMS.
HIGH PRESSURE WILL KEEP DRY AND WARM CONDITIONS THROUGH WEDNESDAY
NIGHT. MODELS HAVE SLOWED ARRIVAL OF RAIN LATER IN THE WEEK...AND
THIS LOOKS REASONABLE WITH SOUTHWEST FLOW ALOFT KEEPING SYSTEMS TO
THE WEST. THUS REMOVED POPS FOR THURSDAY AND WENT DRY.
UPPER FLOW WILL GRADUALLY FLATTEN OUT LATE NEXT WEEK AND ALLOW A
COLD FRONT TO MOVE IN. WILL KEEP RAIN CHANCES THURSDAY NIGHT INTO
FRIDAY.
TEMPERATURES WILL BE ABOVE AVERAGE DURING THE LONG TERM.
&&
.AVIATION /DISCUSSION FOR THE 121200Z TAF ISSUANCE/...
ISSUED AT 626 AM EDT SAT SEP 12 2015
OUTSIDE OF ANY SHOWERS TODAY...VFR EXPECTED THROUGH THE PERIOD.
CLOUDS WILL DEVELOP/INCREASE QUICKLY THIS MORNING AS AN UPPER LEVEL
SYSTEM MOVES INTO THE AREA. SCATTERED SHOWERS WILL DEVELOP WITH THIS
FEATURE AS WELL...BUT RANDOM NATURE OF SHOWERS AND COVERAGE EXPECTED
WARRANT ONLY A VCSH MENTION AT THE TAF LOCATIONS. BRIEF MVFR
CONDITIONS ARE POSSIBLE IN ANY SHOWER.
SHOWERS WILL TAPER OFF THIS AFTERNOON AND CEILINGS SHOULD DISSIPATE
BY EARLY EVENING...LEAVING BEHIND VFR CONDITIONS OVERNIGHT. CANNOT
ABSOLUTELY RULE OUT SOME PATCHY FOG LATE TONIGHT BUT CONFIDENCE IS
TOO LOW TO MENTION.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...50
NEAR TERM...RYAN
SHORT TERM...50
LONG TERM....50
AVIATION...50
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1204 PM EDT SAT SEP 12 2015
.SYNOPSIS...
AN UPPER TROUGH WILL KEEP US IN A COOL AND UNSETTLED WEATHER
PATTERN THROUGH THE REMAINDER OF THE WEEKEND. HIGH PRESSURE AND
MORE SEASONABLE TEMPERATURES WILL RETURN ON MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
BULK OF THE MOISTURE ASSOCIATED WITH THE COLD FRONT IS NOW EAST OF
THE AREA. HOWEVER...SOME LIGHT RAIN/DRIZZLE CONTINUES FURTHER
WEST WHERE SOME DRY AIR HAS ENCROACHED IN THE MID LEVELS. BOTH THE
NAM AND THE HRRR SUGGEST THAT THE SHOWERS OVER OHIO WILL CONTINUE
TO FILL IN AS THE SURFACE LOW DEPARTS TO THE EAST. OPTED TO CARRY
HIGH CHANCE POPS FOR THE REMAINDER OF THE AFTERNOON AND OVERNIGHT
FOR THIS LINGERING PRECIPITATION...AS WELL AS ANY LAKE ENHANCED
SHOWERS THAT DEVELOP IN THE COOL NW FLOW ALOFT.
CLOUD COVER...SHOWERS...AND 850HPA TEMPERATURES FALLING TOWARD 3C
WILL KEEP TEMPERATURES BELOW NORMAL TODAY...WITH HIGHS LIKELY TO
TOP OUT IN THE LOW TO MID 60`S. TONIGHTS LOWS WERE CONSTRUCTED
FROM MAV/MET VALUES.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY/...
LOW CONVECTIVE THRESHOLDS UNDER THE ENCROACHING HIGH AMPLITUDE
UPPER TROUGH AND LOW LEVEL FLOW OFF THE LAKES IS EXPECTED TO
SUPPORT ISOLD TO SCT SHOWERS...SO SLIGHT TO CHANCE PRECIP PROBS
WERE MAINTAINED THROUGH SUNDAY. LITTLE ADJUSTMENT WAS NEEDED FOR
THE TEMPERATURE FORECAST...ABOUT 10 DEGREES BELOW NORMAL.
TROUGH IS PROJECTED TO LIFT NORTHEASTWARD RAPIDLY BY MONDAY.
SUBSIDENCE/RISING HEIGHTS/INSOLATION WILL ALL SUPPORT A RAPID
TEMPERATURE MODERATION TO...AND THEN ABOVE SEASONAL AVERAGES BY
THE END OF THE SHORT TERM PERIOD.
&&
.LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/...
RIDGING IS PROGGED ACROSS THE EASTERN CONUS THROUGH MUCH OF THE
PERIOD WITH DRY AND WARM CONDITIONS EXPECTED. AS THE RIDGE SLIDES
EAST BY LATE WEEK...ZONAL FLOW IS PROGGED TO DEVELOP. AN EMBEDDED
SHORTWAVE IN THE FLOW COULD RETURN RAIN CHANCES TO THE REGION BY
NEXT WEEKEND. WPC ENSEMBLE BASED GUIDANCE WAS USED FOR THE
EXTENDED PERIOD WITH UPWARD ADJUSTMENTS TO LOW TEMPS.
&&
.AVIATION /16Z SATURDAY THROUGH WEDNESDAY/...
IFR CONDITIONS WILL GRADUALLY IMPROVE TO MVFR THIS AFTERNOON AS
THE SURFACE LOW/CDFNT EXITS...THOUGH UPPER TROUGHING SHOULD
CONTINUE TO BRING MVFR STRATOCU OVERNIGHT.
OUTLOOK...SUNDAY THROUGH WEDNESDAY...
RESTRICTIONS ARE POSSIBLE EARLY SUNDAY WITH THE UPPER TROUGH.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
900 AM PDT SAT SEP 12 2015
.UPDATE...MESOSCALE DISCUSSION:
THE SETUP FOR THUNDERSTORM ACTIVITY THIS AFTERNOON IS BEING CLOSELY
MONITORED THIS MORNING. SPC MESOANALYSIS...SATELLITE TRENDS AND
CONVECTION ALLOWING MODELS ARE PROVIDING MORE INSIGHT INTO HOW
THINGS WILL DEVELOP.
CLEAR SKIES ACROSS THE ENTIRE AREA WILL ALLOW FOR AMPLE SUN AND
DESTABIZES THE ATMOSPHERE AS WE HEAD INTO THE AFTERNOON HOURS. MUCH
OF THE LOW LEVEL MOISTURE REMAINS SOUTH OF A LINE FROM KINGMAN TO
BARSTOW AS EVIDENCED BY DEW POINTS IN THE MID TO UPPER 50S AND
PRECIPITABLE WATER VALUES FROM 1.0-1.5 IN THAT AREA. UPPER AIR
SOUNDINGS FROM THIS MORNING INDICATE SOME STEEP MID-LEVEL
TEMPERATURE LAPSE RATES (7-8 C/KM) ACROSS THE ENTIRE AREA.
SO...THIS MEANS WE EXPECT TO GET GOOD CONVECTIVE DEVELOPMENT IN
AREAS WHERE THE LOW LEVEL MOISTURE AND SUNSHINE DESTABILIZES THE
LOWER LEVELS ENOUGH TO TAKE ADVANTAGE OF THE UNSTABLE MID-LEVEL
LAPSE RATES.
SINCE THE LOW LEVEL MOISTURE IS MORE PREVALENT IN THE SOUTH PART OF
THE CWA...WE WOULD EXPECT MORE LOW BASED RAIN PRODUCERS. WHILE
FURTHER NORTH (OVER LAS VEGAS...KINGMAN AND LAUGHLIN AREAS) WE WOULD
EXPECT HIGHER-BASED STORMS WITH LESS RAIN AND GUSTY WINDS DUE TO
DOWNDRAFTS. DCAPE VALUES FROM THE MESOANAYSIS SUPPORT THIS IDEA AS
WELL.
CONVECTION ALLOWING MODELS SEEM TO HINT AT A SIMILAR SCENARIO AS
MENTIONED ABOVE. THE HRRR SPECIFICALLY IS GENERATING THUNDERSTORMS
BEGINNING AT 20UTC IN A LINE FROM KINGMAN TO RIDGECREST, CA AND
ALSO OVER EXTREME SOUTHWEST SAN BERNARDINO COUNTY NEAR YUCCA VALLEY
AND TWENTYNINE PALMS. LAS VEGAS WILL LIKELY BE ON THE NORTHERN
FRINGE OF ACTIVITY. LAUGHLIN...KINGMAN...BAKER...BARSTOW AND
TWENTYNINE PALMS WILL HAVE A BETTER CHANCE OF SEEING THUNDERSTORMS
TODAY.
&&
.PREV DISCUSSION... /ISSUED 358 AM PDT SAT SEP 12 2015/
.SYNOPSIS...SLIGHT CHANCES FOR THUNDERSTORMS WILL CONTINUE OVER THE
HIGHER TERRAIN TO THE SOUTH AND WEST OF LAS VEGAS TODAY. MOISTURE
ASSOCIATED WITH THE REMNANTS OF HURRICANE LINDA WILL BRING MORE
WIDESPREAD CLOUD COVER...SHOWER ACTIVITY...AND COOLER TEMPERATURES
SUNDAY THROUGH TUESDAY. CONDITIONS WILL BEGIN TO DRY OUT FROM WEST
TO EAST LATE TUESDAY AND WEDNESDAY.
&&
.SHORT TERM...TODAY THROUGH MONDAY.
FOR TODAY...A VERY SLIGHT UPTICK IN CONVECTION IS EXPECTED AS HIGH
PRESSURE BEGINS TO LOSE ITS GRIP ON THE REGION. THIS WILL WEAKEN THE
CAP...BUT NOT ENOUGH TO EXPECT MUCH MORE THAN ISOLATED THUNDERSTORMS
OVER THE HIGHER TERRAIN IN AREAS SOUTH AND WEST OF LAS VEGAS. BY THE
LATE AFTERNOON/EVENING...OUTFLOW BOUNDARIES WILL LIKELY BECOME THE
DOMINANT FORCING MECHANISM...ALLOWING ISOLATED STORMS TO MOVE INTO
NEARBY VALLEY LOCATIONS. ONCE AGAIN WITH ONLY LOW-GRADE MOISTURE
LEVELS TO WORK WITH...THE PRIMARY IMPACTS FROM ANY STORMS TODAY WILL
MAINLY BE WIND-RELATED. STORMS WILL AGAIN TAPER OFF AROUND SUNSET
WITH THE LOSS OF HEATING.
SUNDAY...A SHORTWAVE ASSOCIATED WITH THE REMNANTS OF FORMER
HURRICANE LINDA WILL EJECT ACROSS THE REGION BRINGING CHANCES FOR
SHOWERS AND THUNDERSTORMS TO MUCH OF THE AREA. MOISTURE AND
INSTABILITY PARAMETERS WITH 00Z GUIDANCE CONTINUE TO POINT TOWARD
MOHAVE AND LINCOLN COUNTIES AS THE MOST FAVORED AREAS FOR SHOWER AND
THUNDERSTORM DEVELOPMENT THE AFTERNOON HOURS. WHILE THIS IS
CONSISTENT WITH PREVIOUS 12Z MODEL GUIDANCE...CLOUD COVER CONTINUES
TO BE A VIABLE PLAYER IN THE POTENTIAL OUTCOME FOR SUNDAY...AS TOO
MUCH WILL MITIGATE THUNDERSTORM CHANCES. IT IS NOTED THAT THE PAST
SEVERAL RUNS OF THE GFS/ECMWF/NAM HAVE BEEN QUICKER IN TRAVERSING
THE BAND OF CLOUD COVER ACROSS THE REGION ASSOCIATED WITH THE
SHORTWAVE...SUPPORTING THE MOISTURE AND INSTABILITY PARAMETERS
PROGGED BY 00Z GUIDANCE. IT CONTINUES TO LOOK LIKELY THAT DRY MID-
LEVEL AIR WILL QUICKLY INTRUDE THE WESTERN ZONES BEHIND THE
SHORTWAVE...LEADING TO SUBSIDENCE ALOFT AND LIMITING SHOWER AND
THUNDERSTORM ACTIVITY ACROSS SAN BERNARDINO AND SOUTHERN INYO
COUNTIES SUNDAY. AS A RESULT...POPS WERE GREATLY LIMITED ACROSS
THESE AREAS AND FAVORED ACROSS NORTHERN AND EASTERN POSITIONS OF
THE FORECAST AREA WITH MODERATE-HIGH CONFIDENCE IN TONIGHTS
FORECAST PACKAGE.
GUIDANCE IS IN GOOD AGREEMENT AND REMAINS CONSISTENT WITH TRENDS
SET WITH 12Z GUIDANCE IN CONTINUING TO SPREAD THE AFOREMENTIONED
DRY AIR ACROSS THE REGION MONDAY...EFFECTIVELY CAPPING MUCH OF THE
FORECAST AREA AND LIMITING THUNDERSTORM CHANCES FOR MUCH OF THE
DAY. NAM AND GFS BUFR SOUNDINGS ACROSS THE CWA DEPICT A RATHER
SUBSTANTIAL CAP DEVELOPING IN RESPONSE TO THIS DRY MID-LEVEL
INTRUSION...WITH THE STRONGEST INVERSIONS PROGGED ACROSS SOUTHERN
LOCALES. LOCATIONS IN NORTHERN INYO...ESMERALDA AND LINCOLN
COUNTIES DEPICT LESS OF A CAP...MAKING THESE AREAS MORE FAVORABLE
FOR SHOWER AND STORM DEVELOPMENT DURING THE DAYTIME HOURS.
OPERATIONAL GUIDANCE DOES DEVELOP PRECIPITATION BY MID TO LATE
AFTERNOON...IN RESPONSE TO A QUICK SHOT OF MODERATE MID-LEVEL
MOISTURE ASSOCIATED WITH A SECONDARY SHORTWAVE TRAVERSING THE
REGION. AS MENTIONED IN THE PREVIOUS DISCUSSION...THE TIMING OF
THIS FEATURE WILL BE VITAL TO THE OUTCOME ON MONDAY. IT DOES
APPEAR THAT 00Z GUIDANCE IS MORE IN LINE THAN PREVIOUS GUIDANCE
REGARDING THE TIMING OF THIS FEATURE...THEREFORE MORE SUBSTANTIAL
CHANGES WERE MADE TO THE POP AND WEATHER GRIDS TONIGHT WITH
MODERATE CONFIDENCE. THUNDERSTORM CHANCES WERE LIMITED TO THE
AFOREMENTIONED WEAKLY CAPPED AREAS...AS WELL AS EASTERN PORTIONS
OF LINCOLN...CLARK AND NORTHERN MOHAVE COUNTIES LATE MONDAY
AFTERNOON WITH SHOWERS AND STORMS LINGERING INTO MONDAY NIGHT.
TEMPERATURES ARE EXPECTED TO COOL 4-5 DEGREES EACH DAY THROUGH
MONDAY...REACHING SEASONAL AVERAGES FOR MID-SEPTEMBER.
.LONG TERM...TUESDAY THROUGH FRIDAY.
BY TUESDAY...MODELS HAVE COME INTO BETTER AGREEMENT THAT HIGHER
GRADE MOISTURE ASSOCIATED WITH THE CORE OF FORMER HURRICANE LINDA
WILL BE PUSHED ACROSS THE REGION (INSTEAD OF OUT TO SEA AS SOME
GUIDANCE SHOWED JUST 24 HOURS AGO) BETWEEN 12Z TUESDAY AND 18Z
WEDNESDAY. THE SIZE OF THIS SLUG OF MOISTURE IS LIKELY TO BE
RELATIVELY SMALL...BUT THE AMOUNT OF MOISTURE COULD BE SUBSTANTIAL
(PWATS NEAR THE CORE LOOK TO APPROACH 1.7 INCHES)...THEREFORE THE
EXACT TRACK AND TIMING BECOME CRITICAL TO THE FORECAST THROUGH
TUESDAY/TUESDAY NIGHT. MODELS DIFFERENCES AT THIS STAGE WILL KEEP
CONFIDENCE MODERATE. THAT SAID...I DID MAKE A SOME SIGNIFICANT
CHANGES TO AREAL PRECIPITATION COVERAGE AND CHANCES THROUGH TUESDAY.
THE MAIN CHANGE WAS ADDING CHANCES FOR PRECIPITATION ACROSS MUCH OF
SAN BERNARDINO COUNTY FOR TUESDAY. I LIMITED THE CHANCES FOR THUNDER
FOR MUCH OF SAN BERNARDINO AND CLARK COUNTIES TO A SLIGHT CHANCE
BASED ON THE LIKELIHOOD OF LIMITED INSTABILITY ASSOCIATED WITH THE
SUBSTANTIAL AMOUNT OF LOW/MID-LEVEL CLOUD COVER CURRENTLY DEPICTED
WITH THIS SLUG AS IT MOVES ACROSS. ANOTHER CONCERN IS THE AMOUNT OF
AVAILABLE DEEP LAYER SHEAR...WHICH WILL RANGE FROM 30-50KTS ACROSS A
GOOD PORTION OF THE AREA. THIS COULD LEAD TO A FEW STRONGER OR MORE
ORGANIZED STORMS IF THINGS DESTABILIZE DECENTLY.
AGAIN BY ROUGHLY 18Z WEDNESDAY THIS SLUG OF ENHANCED MOISTURE SHOULD
BE RAPIDLY EXITING THE AREA...AND HAVE LEFT IN ONLY A SLIGHT CHANCE
OF SHOWERS/THUNDERSTORMS ACROSS THE NORTHEASTERN PORTION OF THE
FORECAST AREA BY WEDNESDAY AFTERNOON. BY THE EVENING...CONDITIONS
ARE LIKELY TO BE RELATIVELY DRY AREA WIDE.
FOR THURSDAY AND FRIDAY EXPECT ZONAL FLOW OR WEAK TROUGHING ACROSS
THE REGION. THIS SHOULD KEEP THINGS RELATIVELY DRY THROUGH THE END
OF THE WORK WEEK...OF NOT OCCASIONALLY BREEZY.
TEMPERATURES ARE EXPECTED TO CLIMB FROM A FEW DEGREES BELOW NORMAL
TUESDAY TO NEAR OR JUST ABOVE NORMAL BY THE END OF THE WEEK.
&&
.AVIATION...FOR MCCARRAN...OUTSIDE OF ANY OUTFLOW BOUNDARIES LIGHT
WINDS GENERALLY UNDER 8 KTS FAVORING AN EASTERLY DIRECTION ARE
EXPECTED LATE MORNING THROUGH THIS AFTERNOON. SOUTHWESTERLY WINDS
WILL PICK UP THIS EVENING...WITH SPEEDS OF 8-12 KTS POSSIBLE BEFORE
MIDNIGHT. ISOLATED SHRA/TSRA POSSIBLE MAINLY TO THE SOUTH AND WEST
OF KLAS TODAY. MOISTURE AND CHANCES FOR TSRA/SHRA AND LOWERED CIGS
TO 7-8K FEET WILL INCREASE SUNDAY AND LAST THROUGH EARLY NEXT WEEK.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...ISOLATED SHRA/TSRA WILL BE POSSIBLE TODAY...PRIMARILY
OVER THE MOUNTAINS TO THE SOUTH AND WEST OF KLAS. GUSTY AND ERRATIC
WINDS ARE POSSIBLE IN AND NEAR ANY SHRA/TSRA...OTHERWISE RELATIVELY
LIGHT WINDS WILL FAVOR A SOUTHERLY DIRECTION DURING THE
AFTERNOON/EVENING AND TYPICAL DIURNAL DIRECTIONS OVERNIGHT. AREAS OF
FU AND HZ ARE POSSIBLE IN AROUND KBIH REDUCING VSBY AND CREATING
LOCAL MOUNTAIN OBSCURATIONS. MOISTURE AND CHANCES FOR TSRA/SHRA AND
LOWERED CIGS OF 5-10K FEET WILL INCREASE SUNDAY AND LAST INTO EARLY
NEXT WEEK.
&&
&&
$$
UPDATE: LERICOS
SHORT TERM: WOLCOTT/PULLIN
LONG TERM: PULLIN
FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:
HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
914 AM EDT SAT SEP 12 2015
.SYNOPSIS...
AN UPPER LEVEL TROUGH OVER THE AREA WILL SLOWLY MOVE
OFF TO THE EAST THROUGH SUNDAY. HIGH PRESSURE WILL MOVE UP THE OHIO
VALLEY SUNDAY AND MONDAY AND INTO PENNSYLVANIA TUESDAY AND
WEDNESDAY. A COLD FRONT SHOULD MOVE EAST INTO THE AREA BY LATE
FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
MAIN BULK OF RAINFALL IS HEADED EAST OF THE AREA AT THIS TIME.
SOME RESIDUAL CYCLONIC FLOW MOISTURE CONTINUES TO STREAM BACK OVER
THE FORECAST AREA THIS MORNING. DECIDED BASED ON LATEST HRRR MODEL
THAT SOME FILLING WILL TAKE PLACE OVER THE AREA AND BRING BACK
MORE SHOWERS THIS MORNING INTO THE EARLY AFTERNOON. THIS SHOULD
THEN GRADUALLY TAPER OFF FROM WEST TO EAST AS THE DAY PROGRESSES.
SOME AREAS WILL MAINLY SEE DRIZZLE BUT KEPT IT ALL RAIN FOR NOW.
TEMPERATURES ACROSS THE AREA WILL HOLD PRETTY MUCH STEADY STATE
THROUGH THE DAY AS COLD AIR ADVECTION TAKES PLACE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
CONDITIONS WILL REMAIN FAVORABLE FOR LAKE EFFECT SHRA INTO SUN NIGHT
UNTIL HIGH PRESSURE BUILDS IN FROM THE SW. WINDS WILL CONTINUOUSLY
BACK SO THE BANDS OF LAKE EFFECT WILL SLOWLY SHIFT FROM A NORTH TO
SOUTH ORIENTATION TO A WEST TO EAST ORIENTATION. THIS SHOULD KEEP
ANY ONE SPOT FROM SEEING TOO MUCH RAIN AS THE FOCUS LOCATION SLOWLY
MOVES ENE UP THE LAKESHORE. TEMPS ON SUN WILL REMAIN UNSEASONABLY COOL
WITH HIGHS MOSTLY FROM THE UPPER 50S INLAND EAST TO 60 TO 65 WEST.
HIGH PRESSURE SLOWLY SHIFTING FROM WV INTO PA MON INTO TUE SHOULD
BRING DRY CONDITIONS WITH WARMING TEMPS AS MORE SUNSHINE RETURNS AND
WINDS SHIFT MORE TO THE SOUTH.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
ABOVE NORMAL TEMPERATURES WILL RETURN DURING THE PERIOD AS LONG
WAVE RIDGING DEVELOPS OVER THE EASTERN STATES. THE SOUTHERN EDGE
OF THE WESTERLIES WILL BUCKLE ON FRIDAY AND INTO NEXT SATURDAY AS
A SHORT WAVE AND ASSOCIATED COLD FRONT MOVE INTO THE GREAT LAKES.
BOTH THE ECMWF AND THE GFS ARE VERY SIMILAR WHICH INCREASES
CONFIDENCE. UNTIL THEN A RATHER PLEASANT LATE SUMMER PERIOD WITH
TRANQUIL CONDITIONS IS EXPECTED. HAVE USED WPC TEMPERATURES WITH
SLIGHT CHANGES.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
MOST OF THE POST FRONTAL RAIN HAS MOVED EAST OF THE TAF SITES WITH
JUST A LITTLE LINGERING RAIN FROM NEAR CLE TO MFD WITH VFR
CONDITIONS FARTHER WEST. STILL EXPECT MORE SHOWER DEVELOPMENT THIS
AFTERNOON AS COLD AIR ALOFT MOVES INTO THE REGION ALONG WITH
INSTABILITY FROM WARM LAKE ERIE. SHORT TERM SUBSIDENCE WILL
SUPPRESS UPWARD VERTICAL MOTION FOR A TIME BEFORE SCATTERED
SHOWERS DEVELOP. CIGS WILL GRADUALLY LIFT TO MVFR EAST OF I-71.
SOME IMPROVEMENT IN CIGS CAN BE EXPECTED TONIGHT.
VFR CONDITIONS ARE EXPECTED AT TOL AND FDY AS THE INFLUENCE OF
LAKE ERIE WILL BE MINIMAL.
OUTLOOK...NON VFR CONTINUING THROUGH SUNDAY...ESPECIALLY FOR NE
OH AND NW PA IN SCATTERED SHOWERS/TSRA.
&&
.MARINE...
RATHER UNSETTLED CONDITIONS ARE EXPECTED ACROSS LAKE
ERIE IN THE WAKE OF A COLD FRONT THAT CROSSED THE REGION. THE
PRESSURE GRADIENT HAS INCREASED ACROSS THE LAKE IN COMBINATION
WITH COLD AIR SPREADING SOUTHWARD. WITH COLDER AIR ALOFT AND STILL
RATHER WARM LAKE SURFACE OF 24 C...STRONGER WINDS ALOFT WILL MIX
DOWN TO THE LAKE SURFACE AND PRODUCE SMALL CRAFT ADVISORY
CONDITIONS ESPECIALLY AT THE END OF THE FETCH WHICH IS ON THE
SOUTH SHORE OF THE LAKE. WINDS OF 15 TO 25 KNOTS WILL PERSIST
TODAY WITH SOME GRADUAL DECREASE TONIGHT AND ESPECIALLY SUNDAY.
WILL LEAVE THE SCA IN AFFECT UNTIL SUNDAY AFTERNOON.
WITH HIGH PRESSURE NEAR THE REGION WELL INTO NEXT WEEK...A
TRANQUIL PERIOD IS EXPECTED ON THE LAKE FROM SUNDAY NIGHT INTO THE
MIDDLE OF NEXT WEEK.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...BEACH HAZARDS STATEMENT UNTIL 8 PM EDT THIS EVENING FOR OHZ007-
009>012-089.
PA...BEACH HAZARDS STATEMENT UNTIL 8 PM EDT THIS EVENING FOR PAZ001.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 PM EDT SUNDAY FOR LEZ142>149.
&&
$$
SYNOPSIS...ADAMS
NEAR TERM...LOMBARDY
SHORT TERM...ADAMS
LONG TERM...LAPLANTE
AVIATION...LAPLANTE
MARINE...LAPLANTE
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
901 AM EDT SAT SEP 12 2015
.SYNOPSIS...
COLD FRONT EXITS EAST TODAY. UPPER LOW TONIGHT INTO SUNDAY WITH
UNSEASONABLY COOL WEATHER. HIGH PRESSURE LINGERS THROUGH MUCH OF
NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
MADE JUST VERY MINOR TWEAKS TO POPS BASED ON LATEST RADAR
TRENDS...BUT NO REAL CHANGES TO THE EXPECTED SENSIBLE WEATHER IN
THE FORECAST FOR TODAY. COOLER AND DAMP SUMS IT UP. LOWERED POPS
SLIGHTLY ALONG THE OHIO RIVER COUNTIES...AND PUSHED FRONT TO THE
EAST BY AN HOUR OR TWO BY TRIMMING BACK POPS OVER EAST CENTRAL WV
A LITTLE EARLIER. OVERALL...THIS LEADS TO NOT MUCH CHANGE TO THE
FORECAST PACKAGE. A CLOUDY AND DREARY DAY EXPECTED...AS PRECIP
COMES TO AN END ACROSS THE EAST...ON THE HEELS OF COLD FRONT
PASSAGE. LATEST RAP DRAPES A POST FRONTAL TROF AND COOL POOL
ALOFT...MAINLY ALIGNED ALONG THE OH RIVER...WITH FEATURE TRACKING
EAST BY EVENING. WITH LOW LEVEL MOISTURE IN PLACE...THESE FEATURES
WILL LIKELY CONTINUE TO KICK OFF SPOTTY SHOWERS...AND THIS COVERED
WITH GRADUALLY INCREASING CHC POPS LATER TODAY...MORE FOCUSED
ACROSS THE NORTH AND EAST AS WEAK WAVE MOVES ACROSS.
TEMPS FORECAST ON TRACK AND NO CHANGES MADE IN THE NEAR TERM.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
UPPER TROF AXIS AND WEAK VORT WILL ROTATE THROUGH THE REGION ON
SUNDAY. KEPT SLGT CHC AND CHC POPS IN THE FORECAST EARLY
SUNDAY...MAINLY EAST OF THE OHIO RIVER. TROF AXIS WILL CONTINUE
TO LIFT OUT DURING THE DAY ON SUNDAY AND ANY LEFT OVER SHOWERS
WILL END BY EARLY EVENING SUNDAY...IN THE WV MOUNTAINS. MUCH
COOLER AIR WILL WORK ITS WAY IN SUNDAY NIGHT AS HIGH PRESSURE
BUILDS ACROSS THE REGION. TEMPS WILL BE RATHER CHILLY DROPPING
DOWN INTO THE 40S OVER MUCH OF THE AREA AND EVEN UPPER 30S IN THE
COOLER MOUNTAIN VALLEYS OF WV.
HIGH PRESSURE WILL CONTINUE TO BUILD OVER THE REGION DURING THE
DAY ON MONDAY WITH COOLER THAN NORMAL TEMPS.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
MODELS SHOW BROAD SFC HIGH PRESSURE BUILDING IN BEHIND THE FRONT
WHICH WILL BE IN CONTROL WITH A PROLONGED DRY CONDITIONS THROUGH THE
PERIOD. EXPECT A WARMING TREND NEXT WEEK. WENT WITH THE SUPER BLEND
AND HPC GUIDANCE FOR TEMPERATURES AND DEWPOINTS THROUGH THE PERIOD.
&&
.AVIATION /13Z SATURDAY THROUGH WEDNESDAY/...
COLD FRONT ENTERING THE WV MOUNTAINS...WITH SHOWERS ALONG AND
BEHIND IT. FOR THE MOST PART...VISIBILITIES IN THE SHOWERS HAVE
BEEN MVFR OR BETTER. HOWEVER...IFR CIGS ARE COMMON. EXPECT THOSE
TO GRADUALLY IMPROVE TO MVFR FROM WEST TO EAST THROUGH THE
MORNING. DRIZZLE AND SCATTERED SHOWERS SHOULD PERSIST FOR MUCH OF
THE DAY...INCLUDED VCSH DUE TO UNCERTAINTY ON EXACT PLACEMENT AND
TIMING.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z SUNDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: VISIBILITIES AND CEILINGS COULD BE LOWER IN
SHOWERS AND BEHIND THE FRONT.
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 12 13 14 15 16 17 18 19 20 21 22 23
EDT 1HRLY 08 09 10 11 12 13 14 15 16 17 18 19
CRW CONSISTENCY L L M M M M M M M M M M
HTS CONSISTENCY M M M M M M M M M M H H
BKW CONSISTENCY L L L L L M M M M M M M
EKN CONSISTENCY L L L L M M M M M M M M
PKB CONSISTENCY M M M M M M M M M M M H
CKB CONSISTENCY L M M M M M M M M M M M
AFTER 12Z SUNDAY...
WIDESPREAD IFR CONDITIONS NOT EXPECTED.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...JS/MZ
NEAR TERM...KMC
SHORT TERM...JS
LONG TERM...ARJ
AVIATION...MZ
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1106 AM EDT SAT SEP 12 2015
.SYNOPSIS...
A SLOW MOVING FRONTAL SYSTEM WILL MOVE OFF THE COAST TONIGHT. THE
UPPER LEVEL LOW ASSOCIATED WITH THE FRONT WILL KEEP US UNSETTLED
THROUGH SUNDAY. FAIR AND WARMER CONDITIONS WILL RETURN BEGINNING
MONDAY AND CONTINUE THROUGH MOST OR ALL OF NEXT WEEK AS A LARGE
AREA OF HIGH PRESSURE DRIFTS OVER THE OHIO VALLEY AND MID ATLANTIC
REGION.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE WAVY FRONT PRETTY MUCH BISECTS THE FORECAST AREA WITH AT LEAST
ONE SURFACE LOW FOUND IN THE MESO ANAL DOWN OVER SW VIRGINIA.
RADAR TRENDS SHOW PRECIP BEGINNING TO BLOSSOM OVER MY SOUTHERN
ZONES FROM BEDFORD EAST...SUGGESTING CENTRAL AND EASTERN PA WILL
BE UNDER THE GUN FOR THE NEXT SEVERAL HOURS. THE HRRR SUPPORTS
THIS IDEA OF RAIN CONTINUING TO DEVELOP IN RESPONSE TO
STRENGTHENING UPPER FORCING AS THE NOSE OF THE UPPER JET STREAK
SURGES UP AND INTO PA DURING THE AFTERNOON.
OTHER ISSUE TO CONTEND WITH WILL BE THE POTENTIAL FOR
STRONG/SEVERE THUNDERSTORMS TO DEVELOP IN THE INCREASINGLY
UNSTABLE AIRMASS PUSHING UP INTO SERN PA. SPC HAS PLACED MOST OF
THE LOWER SUSQ VALLEY AND A LARGE PORTION OF THE MID SUSQ VALLEY
AND WRN POCONOS UNDER A MARGINAL RISK OF SVR WX THIS AFTN/EVEN.
CLOUD COVER IS EXTENSIVE AND INSTABILITY ISN`T VERY IMPRESSIVE SO
THE CHANCES WILL NOT BE HIGH...BUT CANNOT RULE OUT AN ISOLATED
STRONG UPDRAFT TO DEVELOP IN THE INCREASINGLY HUMID ENVIRONMENT AS
WIND FIELDS INTENSIFY WITH THE APPROACH OF THE JET.
TEMPS TODAY WILL RISE ONLY VERY SLOWLY ACROSS CENTRAL AND WESTERN
PA THIS MORNING. WARMEST TEMPS TODAY WILL BE OVER THE SUSQ VALLEY
WHERE HIGHS WILL REACH THE LOW TO MID 70S...WHILE THE NW MTNS AND
LAUREL HIGHLANDS SEE THE MERCURY HOLD BETWEEN 59-62F.
HAVE MODIFIED POPS AND STORM TOTAL RAINFALL SLIGHTLY...BUT STILL
FEEL THAT MODEL CONSENSUS STILLS POINTS TWD A BENEFICIAL AMOUNT
OF .50" TO 1.00" INCHES ACROSS THE REGION BY LATE TONIGHT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/...
THE RAIN SHOULD TAPER OFF WITH THE PASSAGE OF SFC COLD FRONT LATE
IN THE DAY ACROSS THE LAUREL HIGHLANDS... AND DURING THE EVENING
HOURS ACROSS THE REST OF CENTRAL PA.
PLENTY OF CLOUDS AND LINGERING SHOWERS WILL OCCUR LATER TONIGHT
AND SUNDAY AS THE CORE OF THE COLD AIR ALOFT TRACKS RIGHT OVERHEAD
SUNDAY AFTERNOON AND NIGHT. A GRADUALLY INCREASING NW BREEZE WILL
OCCUR FOR LATE TONIGHT AND SUNDAY. WIND GUSTS OF 15-20 KTS FROM
THE NW ARE EXPECTED IN MOST PLACES SUNDAY AFTERNOON.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
THE BULK OF THE SENSIBLE WEATHER WILL OCCUR VERY EARLY IN THIS
EXTENDED FCST PERIOD AS WE EXPERIENCE THE EFFECTS OF THE UPPER
TROUGH CLOSING OFF AS IT DROPS THROUGH THE EASTERN GR LAKES AND
EVENTUALLY MOVES OVERHEAD.
ENSEMBLES INDICATE THE RAIN TAPERING TO SHOWERS AND ENDING SUNDAY
NIGHT. THIS WILL SET THE STAGE FOR ANOTHER EXTENDED PERIOD OF DRY
WEATHER WHICH SHOULD LAST THROUGH THE END OF THE WORK WEEK AND
POSSIBLY INTO THE WEEKEND AS THE MEAN UPPER RIDGE IS PROJECTED TO
SURGE BACK INTO THE NERN US.
GEFS AND ECMWF HINT AT SHORTWAVE ENERGY BEGINNING TO CHEW THE TOP
OFF THE RIDGE BY NEXT WEEKEND WHICH LEADS TO THE MENTION OF A
SMALL CHANCE OF SHOWERS...BUT CONFIDENCE IS LOW THIS FAR OUT.
UNTIL THEN IT LOOKS LIKE ANOTHER BOUT OF LATE SUMMER WARMTH ON THE
WAY.
&&
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
THE SURFACE COLD FRONT WILL EDGE SLOWLY EAST ACROSS PA
TODAY...MOVING EAST OF THE REGION OVERNIGHT. WIDESPREAD IFR/MVFR
WILL DOMINATE TODAY...REACHING THE MIDDLE AND UPPER SUSQ VALLEY
TERMINALS BY MID DAY OR EARLY AFTERNOON.
THERE COULD BE ENOUGH INSTABILITY THAT AN ISOLATED THUNDERSTORM
CANNOT BE RULED OUT OVER THE SOUTHERN AND ESPECIALLY SOUTHEASTERN
AREAS THROUGH THE LATE MORNING INTO THE AFTERNOON.
RAIN WILL TAPER TO SHOWERS THIS EVENING AS MAIN WAVE BEGINS TO
EXIT...BUT EXPECT WIDESPREAD IFR /MVFR TO CONTINUE AS THE UPPER
LOW MOVES OVER THE AREA.
AS TROUGH LIFTS TO THE NE....MUCH OF SUNDAY WILL FEATURE GUSTY
WINDS...MVFR CONDITIONS AND SHOWERS...MOST NUMEROUS IN THE NW.
OUTLOOK...
MON-WED...SCT MORNING VALLEY FOG...OTHERWISE VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE/LAMBERT
NEAR TERM...LA CORTE/LAMBERT
SHORT TERM...LAMBERT
LONG TERM...LA CORTE
AVIATION...RXR
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
802 AM EDT SAT SEP 12 2015
.SYNOPSIS...
A FEW WAVES OF LOW PRESSURE AT THE SURFACE WILL MOVE NORTHEAST
ACROSS THE STATE TODAY...AHEAD OF AN UNUSUALLY DEEP UPPER TROUGH
STRETCHED FROM THE UPPER GREAT LAKES TO LOWER OHIO VALLEY THIS
MORNING. THE TROUGH WILL SLOWLY TRACK OVER CENTRAL PENNSYLVANIA
AND LIFT EAST OF THE REGION LATE THIS WEEKEND. FAIR AND WARMER
CONDITIONS WILL RETURN BEGINNING MONDAY AND CONTINUE THROUGH MOST
OR ALL OF NEXT WEEK AS A LARGE AREA OF HIGH PRESSURE DRIFTS OVER
THE OHIO VALLEY AND MID ATLANTIC REGION.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
DEEP DRY AIR IS HOLDING TOUGH ACROSS CENTRAL AND ERN PENN EARLY
THIS MORNING. LOOKING BACK AT THE VARIOUS MODEL GUIDANCE WE HAD 24
HOURS AGO...THE FAVORABLE JET DYNAMICS/STRONG UVVEL FOR STEADY
LIGHT TO MDT RAIN HAVE SHIFTED ABOUT 75-100 NM FURTHER WEST.
CORRESPONDING SFC LOW DEVELOPMENT AND GRADUAL STRENGTHENING
BENEATH THE LEFT EXIT REGION OF A 115 KT SSWRLY 300 MB JET WILL
OCCUR ACROSS NRN WVA EARLY TODAY /INVOF KMGW/ WITH THE TRACK OF
THE LOW LIKELY CLOSE TO THE I-99/ROUTE 220 CORRIDOR IN CENTRAL
PENN.
THIS TRACK HAS FAVORED THE STEADIEST AND HEAVIEST RAIN ACROSS THE
ALLEGHENIES OF NWRN PENN SO FAR...AND THE HRRR OVER THE PAST
SEVERAL HOURS HAS BEEN DEPICTING GRADUAL EASTWARD PROGRESSION AND
SOME DISSIPATION OF THE INITIAL RAIN SHIELD AS IT NEARS THE
INTERSTATE 99 AND RT 220 CORRIDOR IN THE 10Z-15Z PERIOD TODAY.
A RATHER POTENT SHORTWAVE /MIGRATING NNE THROUGH THE MORE
EXTENSIVE APPROX 115 KT UPPER JET CORE/ WILL HELP TO BLOSSOM A
SECOND AREA OF STEADY MODERATE RAIN LATE THIS MORNING THROUGH THE
MID AFTERNOON. THIS WAVE WILL BE ASSOCIATED WITH ELEVATED LIFTED
INDICES NEARING ZERO...WHICH WILL SUPPORT THE CHANCE OF SOME
EMBEDDED/LOW-TOPPED TSRA WITH BRIEFLY HEAVY RAIN. THE MAIN THREAT
FOR TSRA APPEARS TO BE ACROSS OUR FAR SE ZONES AFTER 19 OR 20Z.
03Z SREF SHOWS THE PROB OF CAPE EXCEEDING 1000 J/KG AT ABOUT 30
PERCENT ACROSS SOUTHERN LANCASTER COUNTY WITH LESSER AMOUNTS
JUST TO THE NORTH.
SPC HAS PLACED MOST OF THE LOWER SUSQ VALLEY AND A LARGE PORTION
OF THE MID SUSQ VALLEY AND WRN POCONOS UNDER A MARGINAL RISK OF
SVR WX THIS AFTN/EVEN. ALTHOUGH INCREASING CLOUD COVER LATER THIS
MORNING WILL LIKELY LIMIT DESTABILIZATION...INCREASING MID LVL
FLOW/DEEP LYR SHEAR IMPLIES SOME RISK OF STRONGER STORMS ACROSS
THE LOWER SUSQ VALLEY...WHERE MDLS PRODUCE AFTN CAPES ARND 500
J/KG.
WILL WHITTLE AWAY AND DELAY THE ONSET OF RAIN/SHOWERS ACROSS THE
EASTERN HALF OF THE CWA A LITTLE MORE...THROUGH THE MID MORNING
HOURS IN CENTRAL PENN...AND UNTIL AROUND 15Z FOR MUCH OF THE SUSQ
VALLEY...WHILE MAINTAINING THE SAME POPS /BUT SLIGHTLY LOWER QPF/
ACROSS THE WESTERN MTNS THROUGH 12Z.
TEMPS EARLY TODAY ARE IN A TIGHT...5 DEG F RANGE OF 55-60F ACROSS
THE REGION AT 09Z...AND WILL RISE ONLY VERY SLOWLY ACROSS CENTRAL
AND WESTERN PENN THIS MORNING AS RAIN OVERSPREADS THE REGION.
WARMEST TEMPS TODAY WILL BE OVER THE SUSQ VALLEY WHERE HIGHS WILL
REACH THE LOWTO MID 70S...WHILE THE NW MTNS AND LAUREL HIGHLANDS
SEE THE MERCURY HOLD BETWEEN 59-62F.
HAVE MODIFIED POPS AND STORM TOTAL RAINFALL SLIGHTLY...BUT STILL
FEEL THAT MODEL CONSENSUS STILLS POINTS TWD A BENEFICIAL AMOUNT
OF ONE-HALF TO 1.25 INCHES ACROSS THE REGION BY LATE TONIGHT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/...
THE RAIN SHOULD TAPER OFF WITH THE PASSAGE OF SFC COLD FRONT LATE
IN THE DAY ACROSS THE LAUREL HIGHLANDS... AND DURING THE EVENING
HOURS ACROSS THE REST OF CENTRAL PA.
PLENTY OF CLOUDS AND LINGERING SHOWERS WILL OCCUR LATER TONIGHT
AND SUNDAY AS THE CORE OF THE COLD AIR ALOFT TRACKS RIGHT OVERHEAD
SUNDAY AFTERNNOON AND NIGHT. A GRADUALLY INCREASING NW BREEZE WILL
OCCUR FOR LATE TONIGHT AND SUNDAY. WIND GUSTS OF 15-20 KTS FROM
THE NW ARE EXPECTED IN MOST PLACES SUNDAY AFTERNOON.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
THE BULK OF THE SENSIBLE WEATHER WILL OCCUR VERY EARLY IN THIS
EXTENDED FCST PERIOD AS WE EXPERIENCE THE EFFECTS OF THE UPPER
TROUGH CLOSING OFF AS IT DROPS THROUGH THE EASTERN GR LAKES AND
EVENTUALLY MOVES OVERHEAD.
ENSEMBLES INDICATE THE RAIN TAPERING TO SHOWERS AND ENDING SUNDAY
NIGHT. THIS WILL SET THE STAGE FOR ANOTHER EXTENDED PERIOD OF DRY
WEATHER WHICH SHOULD LAST THROUGH THE END OF THE WORK WEEK AND
POSSIBLY INTO THE WEEKEND AS THE MEAN UPPER RIDGE IS PROJECTED TO
SURGE BACK INTO THE NERN US.
GEFS AND ECMWF HINT AT SHORTWAVE ENERGY BEGINNING TO CHEW THE TOP
OFF THE RIDGE BY NEXT WEEKEND WHICH LEADS TO THE MENTION OF A
SMALL CHANCE OF SHOWERS...BUT CONFIDENCE IS LOW THIS FAR OUT.
UNTIL THEN IT LOOKS LIKE ANOTHER BOUT OF LATE SUMMER WARMTH ON THE
WAY.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
A SURFACE COLD FRONT WILL EDGE SLOWLY EAST ACROSS PA TODAY AS A
LOW PRESSURE TROUGH DEEPENS OVER THE REGION. THE TROUGH WILL
GRADUALLY LIFT NORTHEAST TONIGHT THROUGH SUNDAY.
AREA OF RAIN IMPACTING NORTHWEST MOUNTAINS WITH NUMEROUS SHOWERS
SLIDING INTO THE LAURELS AND CENTRAL/SC MTNS AT 12Z. THESE SHOWERS
WILL INCREASE IN COVERAGE AND IMPACT WESTERN 2/3RDS OF CWA FOR
MUCH OF THE DAY...BRINGING A GENERAL REDUCTION OF CIGS/VSBYS
PEAKING AROUND MIDDAY. DRIER AIR IN PLACE OVER THE EAST WILL FEND
OFF WIDESPREAD SHOWERS A BIT LONGER THERE...WITH RAIN
IMPACTS/REDUCTIONS MAINLY DURING THE AFTERNOON HOURS.
OVERALL...WESTERN AREAS WILL FALL TO IFR WITH CENTRAL AND EASTERN
TERMINALS GENERALLY FALLING INTO THE MVFR CATEGORY. THERE WILL
EVEN BE ENOUGH MID-LEVEL INSTABILITY THAT AN ISOLATED TSTM CAN/T
BE RULED OUT OVER THE SOUTHERN MTNS THIS MORNING AND INTO THE
SUSQ VALLEY THIS AFTERNOON.
RAIN TAPERS TO SHOWERS THIS EVENING AS MAIN WAVE BEGINS TO
EXIT...BUT CIGS DROP TO WIDESPREAD COVERAGE IFR /MVFR SE/ AS
CENTER OF UPPER LOW ARRIVES AND LOW LEVEL FLOW BACKS AROUND TO THE
W-NW AND INCREASES.
AS TROUGH LIFTS TO THE NE....MUCH OF SUNDAY WILL FEATURE GUSTY
WINDS...MVFR CONDITIONS AND SHOWERS /MOST NUMEROUS IN THE NW/.
OUTLOOK...
SUN...CIG RESTRICTIONS AND SCT SHOWERS EARLY...WITH GRADUAL
IMPROVEMENT.
MON-WED...SCT MORNING VALLEY FOG...OTHERWISE VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...LAMBERT
LONG TERM...LA CORTE
AVIATION...RXR
AREA FORECAST DISCUSSION
NWS LINCOLN IL
240 PM CDT SAT SEP 12 2015
.SHORT TERM...(TONIGHT)
ISSUED AT 239 PM CDT SAT SEP 12 2015
Vorticity maximum centered between Springfield and Decatur this
afternoon per water vapor imagery, within the deep upper trough that
covers much of the Midwest. RAP guidance shows a cold pocket of 500
mb temps near -24C just south of this, which has helped feed the
scattered showers that have formed over east central and southeast
Illinois. Drier air in the lower levels have resulted in a bit of
small hail accompanying the heavier showers. Other showers near
Champaign have been tracking south-southwest off Lake Michigan with
more behind them, although wind trajectories are starting to turn
more northerly and the lake feed should shift more to along the
Indiana border. The diurnal cloudiness is fading some across the far
northern CWA, and should rapidly dissipate over the forecast area by
sunset, with mostly clear conditions prevailing overnight. Still
looks to be a cool night, with temperatures falling into the mid
40s.
&&
.LONG TERM...(Sunday THROUGH Saturday)
ISSUED AT 239 PM CDT SAT SEP 12 2015
Morning upper air and moisture channel data depicts deep upper level
over Great Lakes into sotheast MO. Series of weak vort maxes/lobes
in the mid MS river valley rotating through the bottom of the trof,
with main max near Quad Cities moving SSE. With ample low level
moisture, and cold air aloft, scattered showers over the eastern
portions of cwa today, lingering into evening.
Models drift the upper trof to the east into Sunday, allowing
warming low and mid level flow to begin to work into state. Upper
ridge begins to build toward area and slow warming trend into
midweek.
In the extended period, models have agreed a bit more on slowing of
the approaching next frontal system. System approaches now Friday,
with pops delayed into Thursday night, with better chances for rain
Friday and Friday night with front, on the latest run. A bit cooler
with the increased cloud cover with front. Exact details on frontal
passage still somewhat hazy.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1212 PM CDT SAT SEP 12 2015
Little change needed to previous TAF set. Large field of diurnal
clouds sinking southward. Had some brief MVFR conditions as they
developed, but heights have risen recently. Skies will be clearing
from north to south this afternoon, and areas near KPIA/KBMI will
scatter out by mid afternoon. Have left the VCSH mention in due
to an upper low overhead, with the best chances of showers near
KCMI. Gusty north winds will diminish with sunset, and gradually
trend to the west/southwest overnight.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Geelhart
LONG TERM...Goetsch
AVIATION...Geelhart
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
240 PM EDT SAT SEP 12 2015
.UPDATE...
THE LONG TERM SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
ISSUED AT 254 AM EDT SAT SEP 12 2015
AN UPPER LEVEL SYSTEM WILL BRING A CHANCE OF SHOWERS TO THE AREA
TODAY. HIGH PRESSURE WILL THEN BUILD IN AND BRING DRY AND WARMING
CONDITIONS THROUGH MID WEEK NEXT WEEK. A COLD FRONT WILL BRING
CHANCES FOR RAIN AGAIN LATE NEXT WEEK.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 1000 AM EDT SAT SEP 12 2015
UPPER LOW IN THE PROCESS OF CLOSING OFF OVER THE REGION THIS
MORNING WITH A MIX OF CLOUDS AND SUN. SHOWERS ASSOCIATED WITH THE
UPPER ENERGY CONTINUE TO DRIFT SOUTH OFF LAKE MICHIGAN BUT PRECIP
HAS LARGELY STAYED OUT OF THE FORECAST AREA SO FAR THIS MORNING.
TOUCH OF FALL IN THE AIR WITH 14Z TEMPS PRIMARILY IN THE 50S.
FORECAST IN VERY GOOD SHAPE WITH ONLY SUBTLE ADJUSTMENTS NEEDED
FOR THE REST OF THE DAY. COLD POOL ALOFT WILL SETTLE OVER CENTRAL
INDIANA TODAY AND COMBINED WITH THE FORCING ALOFT AND STEEPENING
LAPSE RATES...EXPECT CU TO FILL IN AND ISOLATED TO SCATTERED
SHOWERS DEVELOP INTO THE AFTERNOON. HRRR AND WRF GUIDANCE HAS NICE
HANDLE ON EXPECTATION OF CONVECTIVE DEVELOPMENT...WITH GREATEST
PRECIP COVERAGE MOVING SOUTH ACROSS THE FORECAST AREA WITH THE
UPPER ENERGY THROUGH THE COURSE OF THE AFTERNOON. INSTABILITY
REMAINS VERY WEAK AND LIKELY WILL NOT BE ENOUGH TO GENERATE ANY
LIGHTNING STRIKES.
MADE SOME MINOR ADJUSTMENTS TO TEMPS WITH HIGHS REMAINING
PRIMARILY IN THE LOWER AND MID 60S. GUSTS TO AROUND 20MPH THIS
AFTERNOON WILL GIVE AN EVEN COOLER FALL-LIKE FEEL. ZONE AND GRID
UPDATES OUT.
&&
.SHORT TERM.../TONIGHT THROUGH MONDAY NIGHT/
ISSUED AT 254 AM EDT SAT SEP 12 2015
FOCUS IS ON SKY COVER EARLY IN THE PERIOD. MODELS ARE CLOSE ENOUGH
TO USE A BLEND.
THE UPPER TROUGH WILL MOVE AWAY FROM CENTRAL INDIANA TONIGHT
ALLOWING SOME DECREASE IN CLOUDS. STILL LOOKS TO BE SOME CLOUDS OFF
OF LAKE MICHIGAN THOUGH...SO WENT PARTLY CLOUDY TONIGHT MOST AREAS.
AS WARMER AIR MOVES IN ALOFT SUNDAY ALONG WITH MORE SUBSIDENCE
/THANKS TO RISING HEIGHTS ALOFT AND HIGH PRESSURE MOVING IN AT THE
SURFACE/...CLOUDS WILL DECREASE.
WITH HIGH PRESSURE AROUND FOR THE REMAINDER OF THE SHORT
TERM...EXPECT MOSTLY CLEAR SKIES.
FOR LOW TEMPERATURES TONIGHT WENT WITH A BLEND OF RAW MODEL
TEMPERATURES AS THESE REFLECT THE HIGHER CLOUD COVER WELL. AFTERWARD
A BLEND OF MOS LOOKS GOOD.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
ISSUED AT 239 PM EDT SAT SEP 12 2015
THE LONG TERM BEGINS WITH HIGH PRESSURE AND DRY WEATHER OVER THE
AREA. THE SURFACE HIGH MOVING TO THE EAST WILL ALLOW FOR WARM
ADVECTION OVER THE AREA...AND HIGHS IN THE LOW TO MID 80S CAN BE
EXPECTED WEDNESDAY THROUGH FRIDAY. BY THURSDAY NIGHT THE UPPER
RIDGE OVER THE CENTRAL AND EASTERN U.S. STARTS TO GET SUPPRESSED
AND THIS SETS THE STAGE FOR A COLD FRONT AND A SERIES OF UPPER
WAVES TO MOVE INTO CENTRAL INDIANA AND PROMPT CHANCES FOR
THUNDERSTORMS.
&&
.AVIATION /DISCUSSION FOR 121800Z TAF ISSUANCE/...
ISSUED AT 1254 PM EDT SAT SEP 12 2015
SCATTERED SHOWERS ARE POPPING UP AROUND THE TAF SITES THIS
AFTERNOON. EXPECT THAT THESE COULD BRIEFLY IMPACT THE SITES AND
DROP CONDITIONS TO MVFR/IFR BUT CANNOT HIT ON A PARTICULAR TIME OR
PLACE AND THINK THE IMPACT WILL BE SHORT-LIVED. MIGHT BE CLOSE
ENOUGH TO KHUF AT THIS POINT TO INCLUDE A TEMPO GROUP...BUT
OTHERWISE WILL LEAVE VCSH GOING THROUGH THE AFTERNOON. THIS
EVENING SHOULD SEE CEILINGS START TO SCATTER OUT. COULD BE SOME
BRIEF FOG/MVFR CEILINGS DURING THE OVERNIGHT.
FOR WINDS COULD SEE A FEW GUSTS TO AROUND 15-22 KTS ESPECIALLY
OVER KIND AND KLAF. WINDS WILL BE OUT OF THE NORTHNORTHEAST.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...50
NEAR TERM...RYAN
SHORT TERM...50
LONG TERM....CP
AVIATION...CP
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
102 PM EDT SAT SEP 12 2015
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
ISSUED AT 254 AM EDT SAT SEP 12 2015
AN UPPER LEVEL SYSTEM WILL BRING A CHANCE OF SHOWERS TO THE AREA
TODAY. HIGH PRESSURE WILL THEN BUILD IN AND BRING DRY AND WARMING
CONDITIONS THROUGH MID WEEK NEXT WEEK. A COLD FRONT WILL BRING
CHANCES FOR RAIN AGAIN LATE NEXT WEEK.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 1000 AM EDT SAT SEP 12 2015
UPPER LOW IN THE PROCESS OF CLOSING OFF OVER THE REGION THIS
MORNING WITH A MIX OF CLOUDS AND SUN. SHOWERS ASSOCIATED WITH THE
UPPER ENERGY CONTINUE TO DRIFT SOUTH OFF LAKE MICHIGAN BUT PRECIP
HAS LARGELY STAYED OUT OF THE FORECAST AREA SO FAR THIS MORNING.
TOUCH OF FALL IN THE AIR WITH 14Z TEMPS PRIMARILY IN THE 50S.
FORECAST IN VERY GOOD SHAPE WITH ONLY SUBTLE ADJUSTMENTS NEEDED
FOR THE REST OF THE DAY. COLD POOL ALOFT WILL SETTLE OVER CENTRAL
INDIANA TODAY AND COMBINED WITH THE FORCING ALOFT AND STEEPENING
LAPSE RATES...EXPECT CU TO FILL IN AND ISOLATED TO SCATTERED
SHOWERS DEVELOP INTO THE AFTERNOON. HRRR AND WRF GUIDANCE HAS NICE
HANDLE ON EXPECTATION OF CONVECTIVE DEVELOPMENT...WITH GREATEST
PRECIP COVERAGE MOVING SOUTH ACROSS THE FORECAST AREA WITH THE
UPPER ENERGY THROUGH THE COURSE OF THE AFTERNOON. INSTABILITY
REMAINS VERY WEAK AND LIKELY WILL NOT BE ENOUGH TO GENERATE ANY
LIGHTNING STRIKES.
MADE SOME MINOR ADJUSTMENTS TO TEMPS WITH HIGHS REMAINING
PRIMARILY IN THE LOWER AND MID 60S. GUSTS TO AROUND 20MPH THIS
AFTERNOON WILL GIVE AN EVEN COOLER FALL-LIKE FEEL. ZONE AND GRID
UPDATES OUT.
&&
.SHORT TERM.../TONIGHT THROUGH MONDAY NIGHT/
ISSUED AT 254 AM EDT SAT SEP 12 2015
FOCUS IS ON SKY COVER EARLY IN THE PERIOD. MODELS ARE CLOSE ENOUGH
TO USE A BLEND.
THE UPPER TROUGH WILL MOVE AWAY FROM CENTRAL INDIANA TONIGHT
ALLOWING SOME DECREASE IN CLOUDS. STILL LOOKS TO BE SOME CLOUDS OFF
OF LAKE MICHIGAN THOUGH...SO WENT PARTLY CLOUDY TONIGHT MOST AREAS.
AS WARMER AIR MOVES IN ALOFT SUNDAY ALONG WITH MORE SUBSIDENCE
/THANKS TO RISING HEIGHTS ALOFT AND HIGH PRESSURE MOVING IN AT THE
SURFACE/...CLOUDS WILL DECREASE.
WITH HIGH PRESSURE AROUND FOR THE REMAINDER OF THE SHORT
TERM...EXPECT MOSTLY CLEAR SKIES.
FOR LOW TEMPERATURES TONIGHT WENT WITH A BLEND OF RAW MODEL
TEMPERATURES AS THESE REFLECT THE HIGHER CLOUD COVER WELL. AFTERWARD
A BLEND OF MOS LOOKS GOOD.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
ISSUED AT 254 AM EDT SAT SEP 12 2015
MODELS ARE CLOSE ENOUGH THAT THE SUPERBLEND INITIALIZATION WAS
ACCEPTED FOR MOST ITEMS.
HIGH PRESSURE WILL KEEP DRY AND WARM CONDITIONS THROUGH WEDNESDAY
NIGHT. MODELS HAVE SLOWED ARRIVAL OF RAIN LATER IN THE WEEK...AND
THIS LOOKS REASONABLE WITH SOUTHWEST FLOW ALOFT KEEPING SYSTEMS TO
THE WEST. THUS REMOVED POPS FOR THURSDAY AND WENT DRY.
UPPER FLOW WILL GRADUALLY FLATTEN OUT LATE NEXT WEEK AND ALLOW A
COLD FRONT TO MOVE IN. WILL KEEP RAIN CHANCES THURSDAY NIGHT INTO
FRIDAY.
TEMPERATURES WILL BE ABOVE AVERAGE DURING THE LONG TERM.
&&
.AVIATION /DISCUSSION FOR 121800Z TAF ISSUANCE/...
ISSUED AT 1254 PM EDT SAT SEP 12 2015
SCATTERED SHOWERS ARE POPPING UP AROUND THE TAF SITES THIS
AFTERNOON. EXPECT THAT THESE COULD BRIEFLY IMPACT THE SITES AND
DROP CONDITIONS TO MVFR/IFR BUT CANNOT HIT ON A PARTICULAR TIME OR
PLACE AND THINK THE IMPACT WILL BE SHORT-LIVED. MIGHT BE CLOSE
ENOUGH TO KHUF AT THIS POINT TO INCLUDE A TEMPO GROUP...BUT
OTHERWISE WILL LEAVE VCSH GOING THROUGH THE AFTERNOON. THIS
EVENING SHOULD SEE CEILINGS START TO SCATTER OUT. COULD BE SOME
BRIEF FOG/MVFR CEILINGS DURING THE OVERNIGHT.
FOR WINDS COULD SEE A FEW GUSTS TO AROUND 15-22 KTS ESPECIALLY
OVER KIND AND KLAF. WINDS WILL BE OUT OF THE NORTHNORTHEAST.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...50
NEAR TERM...RYAN
SHORT TERM...50
LONG TERM....50
AVIATION...CP
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
151 PM EDT SAT SEP 12 2015
.SYNOPSIS...
AN UPPER TROUGH WILL KEEP US IN A COOL AND UNSETTLED WEATHER
PATTERN THROUGH THE REMAINDER OF THE WEEKEND. HIGH PRESSURE AND
MORE SEASONABLE TEMPERATURES WILL RETURN ON MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
BULK OF THE MOISTURE ASSOCIATED WITH THE COLD FRONT IS NOW EAST OF
THE AREA. HOWEVER...SOME LIGHT RAIN/DRIZZLE CONTINUES FURTHER
WEST WHERE SOME DRY AIR HAS ENCROACHED IN THE MID LEVELS. BOTH THE
NAM AND THE HRRR SUGGEST THAT THE SHOWERS OVER OHIO WILL CONTINUE
TO FILL IN AS THE SURFACE LOW DEPARTS TO THE EAST. OPTED TO CARRY
HIGH CHANCE POPS FOR THE REMAINDER OF THE AFTERNOON AND OVERNIGHT
FOR THIS LINGERING PRECIPITATION...AS WELL AS ANY LAKE ENHANCED
SHOWERS THAT DEVELOP IN THE COOL NW FLOW ALOFT.
CLOUD COVER...SHOWERS...AND 850HPA TEMPERATURES FALLING TOWARD 3C
WILL KEEP TEMPERATURES BELOW NORMAL TODAY...WITH HIGHS LIKELY TO
TOP OUT IN THE LOW TO MID 60`S. TONIGHTS LOWS WERE CONSTRUCTED
FROM MAV/MET VALUES.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY/...
LOW CONVECTIVE THRESHOLDS UNDER THE ENCROACHING HIGH AMPLITUDE
UPPER TROUGH AND LOW LEVEL FLOW OFF THE LAKES IS EXPECTED TO
SUPPORT ISOLD TO SCT SHOWERS...SO SLIGHT TO CHANCE PRECIP PROBS
WERE MAINTAINED THROUGH SUNDAY. LITTLE ADJUSTMENT WAS NEEDED FOR
THE TEMPERATURE FORECAST...ABOUT 10 DEGREES BELOW NORMAL.
TROUGH IS PROJECTED TO LIFT NORTHEASTWARD RAPIDLY BY MONDAY.
SUBSIDENCE/RISING HEIGHTS/INSOLATION WILL ALL SUPPORT A RAPID
TEMPERATURE MODERATION TO...AND THEN ABOVE SEASONAL AVERAGES BY
THE END OF THE SHORT TERM PERIOD.
&&
.LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/...
RIDGING IS PROGGED ACROSS THE EASTERN CONUS THROUGH MUCH OF THE
PERIOD WITH DRY AND WARM CONDITIONS EXPECTED. AS THE RIDGE SLIDES
EAST BY LATE WEEK...ZONAL FLOW IS PROGGED TO DEVELOP. AN EMBEDDED
SHORTWAVE IN THE FLOW COULD RETURN RAIN CHANCES TO THE REGION BY
NEXT WEEKEND. WPC ENSEMBLE BASED GUIDANCE WAS USED FOR THE
EXTENDED PERIOD WITH UPWARD ADJUSTMENTS TO LOW TEMPS.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
MVFR AND SOME IFR CONDITIONS WILL CONTINUE DUE TO BOTH RESTRICTED
VISIBILITY AND CEILINGS. DRIZZLE AND LIGHT RAIN SHOWERS
OVERNIGHT AS LOW LEVEL MOISTURE REMAINS TRAPPED OVER THE REGION.
UPPER TROUGH TO KEEP STRATOCU OVERNIGHT AND INTO THE MORNING
HOURS SUNDAY.
OUTLOOK...SUNDAY THROUGH WEDNESDAY...
RESTRICTIONS ARE POSSIBLE EARLY SUNDAY WITH THE UPPER TROUGH.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
1102 AM PDT SAT SEP 12 2015
.SYNOPSIS...SLIGHT CHANCES FOR THUNDERSTORMS WILL CONTINUE OVER THE
HIGHER TERRAIN TO THE SOUTH AND WEST OF LAS VEGAS TODAY. MOISTURE
ASSOCIATED WITH THE REMNANTS OF HURRICANE LINDA WILL BRING MORE
WIDESPREAD CLOUD COVER...SHOWER ACTIVITY...AND COOLER TEMPERATURES
SUNDAY THROUGH TUESDAY. CONDITIONS WILL BEGIN TO DRY OUT FROM WEST
TO EAST LATE TUESDAY AND WEDNESDAY.
&&
.UPDATE...MESOSCALE DISCUSSION:
THE SETUP FOR THUNDERSTORM ACTIVITY THIS AFTERNOON IS BEING CLOSELY
MONITORED THIS MORNING. SPC MESOANALYSIS...SATELLITE TRENDS AND
CONVECTION ALLOWING MODELS ARE PROVIDING MORE INSIGHT INTO HOW
THINGS WILL DEVELOP.
CLEAR SKIES ACROSS THE ENTIRE AREA WILL ALLOW FOR AMPLE SUN AND
DESTABIZES THE ATMOSPHERE AS WE HEAD INTO THE AFTERNOON HOURS. MUCH
OF THE LOW LEVEL MOISTURE REMAINS SOUTH OF A LINE FROM KINGMAN TO
BARSTOW AS EVIDENCED BY DEW POINTS IN THE MID TO UPPER 50S AND
PRECIPITABLE WATER VALUES FROM 1.0-1.5 IN THAT AREA. UPPER AIR
SOUNDINGS FROM THIS MORNING INDICATE SOME STEEP MID-LEVEL
TEMPERATURE LAPSE RATES (7-8 C/KM) ACROSS THE ENTIRE AREA.
SO...THIS MEANS WE EXPECT TO GET GOOD CONVECTIVE DEVELOPMENT IN
AREAS WHERE THE LOW LEVEL MOISTURE AND SUNSHINE DESTABILIZES THE
LOWER LEVELS ENOUGH TO TAKE ADVANTAGE OF THE UNSTABLE MID-LEVEL
LAPSE RATES.
SINCE THE LOW LEVEL MOISTURE IS MORE PREVALENT IN THE SOUTH PART OF
THE CWA...WE WOULD EXPECT MORE LOW BASED RAIN PRODUCERS. WHILE
FURTHER NORTH (OVER LAS VEGAS...KINGMAN AND LAUGHLIN AREAS) WE WOULD
EXPECT HIGHER-BASED STORMS WITH LESS RAIN AND GUSTY WINDS DUE TO
DOWNDRAFTS. DCAPE VALUES FROM THE MESOANAYSIS SUPPORT THIS IDEA AS
WELL.
CONVECTION ALLOWING MODELS SEEM TO HINT AT A SIMILAR SCENARIO AS
MENTIONED ABOVE. THE HRRR SPECIFICALLY IS GENERATING THUNDERSTORMS
BEGINNING AT 20UTC IN A LINE FROM KINGMAN TO RIDGECREST, CA AND
ALSO OVER EXTREME SOUTHWEST SAN BERNARDINO COUNTY NEAR YUCCA VALLEY
AND TWENTYNINE PALMS. LAS VEGAS WILL LIKELY BE ON THE NORTHERN
FRINGE OF ACTIVITY. LAUGHLIN...KINGMAN...BAKER...BARSTOW AND
TWENTYNINE PALMS WILL HAVE A BETTER CHANCE OF SEEING THUNDERSTORMS
TODAY.
&&
.AVIATION...FOR MCCARRAN...OUTSIDE OF ANY OUTFLOW BOUNDARIES LIGHT
WINDS GENERALLY UNDER 8 KTS FAVORING AN EASTERLY DIRECTION ARE
EXPECTED. SOUTHWESTERLY WINDS WILL PICK UP THIS EVENING...WITH
SPEEDS OF 8-12 KTS POSSIBLE BEFORE MIDNIGHT. ISOLATED SHRA/TSRA
POSSIBLE MAINLY TO THE SOUTH AND WEST OF KLAS TODAY. MOISTURE AND
CHANCES FOR TSRA/SHRA AND LOWERED CIGS TO 7-8K FEET WILL INCREASE
SUNDAY AND LAST THROUGH EARLY NEXT WEEK.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...ISOLATED SHRA/TSRA WILL BE POSSIBLE TODAY...PRIMARILY
OVER THE MOUNTAINS TO THE SOUTH AND WEST OF KLAS. GUSTY AND ERRATIC
WINDS ARE POSSIBLE IN AND NEAR ANY SHRA/TSRA...OTHERWISE RELATIVELY
LIGHT WINDS WILL FAVOR A SOUTHERLY DIRECTION DURING THE
AFTERNOON/EVENING AND TYPICAL DIURNAL DIRECTIONS OVERNIGHT. AREAS OF
FU AND HZ ARE POSSIBLE IN AROUND KBIH REDUCING VSBY AND CREATING
LOCAL MOUNTAIN OBSCURATIONS. MOISTURE AND CHANCES FOR TSRA/SHRA AND
LOWERED CIGS OF 5-10K FEET WILL INCREASE SUNDAY AND LAST INTO EARLY
NEXT WEEK.
&&
.PREV DISCUSSION... /ISSUED 358 AM PDT SAT SEP 12 2015/
.SHORT TERM...TODAY THROUGH MONDAY.
FOR TODAY...A VERY SLIGHT UPTICK IN CONVECTION IS EXPECTED AS HIGH
PRESSURE BEGINS TO LOSE ITS GRIP ON THE REGION. THIS WILL WEAKEN THE
CAP...BUT NOT ENOUGH TO EXPECT MUCH MORE THAN ISOLATED THUNDERSTORMS
OVER THE HIGHER TERRAIN IN AREAS SOUTH AND WEST OF LAS VEGAS. BY THE
LATE AFTERNOON/EVENING...OUTFLOW BOUNDARIES WILL LIKELY BECOME THE
DOMINANT FORCING MECHANISM...ALLOWING ISOLATED STORMS TO MOVE INTO
NEARBY VALLEY LOCATIONS. ONCE AGAIN WITH ONLY LOW-GRADE MOISTURE
LEVELS TO WORK WITH...THE PRIMARY IMPACTS FROM ANY STORMS TODAY WILL
MAINLY BE WIND-RELATED. STORMS WILL AGAIN TAPER OFF AROUND SUNSET
WITH THE LOSS OF HEATING.
SUNDAY...A SHORTWAVE ASSOCIATED WITH THE REMNANTS OF FORMER
HURRICANE LINDA WILL EJECT ACROSS THE REGION BRINGING CHANCES FOR
SHOWERS AND THUNDERSTORMS TO MUCH OF THE AREA. MOISTURE AND
INSTABILITY PARAMETERS WITH 00Z GUIDANCE CONTINUE TO POINT TOWARD
MOHAVE AND LINCOLN COUNTIES AS THE MOST FAVORED AREAS FOR SHOWER AND
THUNDERSTORM DEVELOPMENT THE AFTERNOON HOURS. WHILE THIS IS
CONSISTENT WITH PREVIOUS 12Z MODEL GUIDANCE...CLOUD COVER CONTINUES
TO BE A VIABLE PLAYER IN THE POTENTIAL OUTCOME FOR SUNDAY...AS TOO
MUCH WILL MITIGATE THUNDERSTORM CHANCES. IT IS NOTED THAT THE PAST
SEVERAL RUNS OF THE GFS/ECMWF/NAM HAVE BEEN QUICKER IN TRAVERSING
THE BAND OF CLOUD COVER ACROSS THE REGION ASSOCIATED WITH THE
SHORTWAVE...SUPPORTING THE MOISTURE AND INSTABILITY PARAMETERS
PROGGED BY 00Z GUIDANCE. IT CONTINUES TO LOOK LIKELY THAT DRY MID-
LEVEL AIR WILL QUICKLY INTRUDE THE WESTERN ZONES BEHIND THE
SHORTWAVE...LEADING TO SUBSIDENCE ALOFT AND LIMITING SHOWER AND
THUNDERSTORM ACTIVITY ACROSS SAN BERNARDINO AND SOUTHERN INYO
COUNTIES SUNDAY. AS A RESULT...POPS WERE GREATLY LIMITED ACROSS
THESE AREAS AND FAVORED ACROSS NORTHERN AND EASTERN POSITIONS OF
THE FORECAST AREA WITH MODERATE-HIGH CONFIDENCE IN TONIGHTS
FORECAST PACKAGE.
GUIDANCE IS IN GOOD AGREEMENT AND REMAINS CONSISTENT WITH TRENDS
SET WITH 12Z GUIDANCE IN CONTINUING TO SPREAD THE AFOREMENTIONED
DRY AIR ACROSS THE REGION MONDAY...EFFECTIVELY CAPPING MUCH OF THE
FORECAST AREA AND LIMITING THUNDERSTORM CHANCES FOR MUCH OF THE
DAY. NAM AND GFS BUFR SOUNDINGS ACROSS THE CWA DEPICT A RATHER
SUBSTANTIAL CAP DEVELOPING IN RESPONSE TO THIS DRY MID-LEVEL
INTRUSION...WITH THE STRONGEST INVERSIONS PROGGED ACROSS SOUTHERN
LOCALES. LOCATIONS IN NORTHERN INYO...ESMERALDA AND LINCOLN
COUNTIES DEPICT LESS OF A CAP...MAKING THESE AREAS MORE FAVORABLE
FOR SHOWER AND STORM DEVELOPMENT DURING THE DAYTIME HOURS.
OPERATIONAL GUIDANCE DOES DEVELOP PRECIPITATION BY MID TO LATE
AFTERNOON...IN RESPONSE TO A QUICK SHOT OF MODERATE MID-LEVEL
MOISTURE ASSOCIATED WITH A SECONDARY SHORTWAVE TRAVERSING THE
REGION. AS MENTIONED IN THE PREVIOUS DISCUSSION...THE TIMING OF
THIS FEATURE WILL BE VITAL TO THE OUTCOME ON MONDAY. IT DOES
APPEAR THAT 00Z GUIDANCE IS MORE IN LINE THAN PREVIOUS GUIDANCE
REGARDING THE TIMING OF THIS FEATURE...THEREFORE MORE SUBSTANTIAL
CHANGES WERE MADE TO THE POP AND WEATHER GRIDS TONIGHT WITH
MODERATE CONFIDENCE. THUNDERSTORM CHANCES WERE LIMITED TO THE
AFOREMENTIONED WEAKLY CAPPED AREAS...AS WELL AS EASTERN PORTIONS
OF LINCOLN...CLARK AND NORTHERN MOHAVE COUNTIES LATE MONDAY
AFTERNOON WITH SHOWERS AND STORMS LINGERING INTO MONDAY NIGHT.
TEMPERATURES ARE EXPECTED TO COOL 4-5 DEGREES EACH DAY THROUGH
MONDAY...REACHING SEASONAL AVERAGES FOR MID-SEPTEMBER.
.LONG TERM...TUESDAY THROUGH FRIDAY.
BY TUESDAY...MODELS HAVE COME INTO BETTER AGREEMENT THAT HIGHER
GRADE MOISTURE ASSOCIATED WITH THE CORE OF FORMER HURRICANE LINDA
WILL BE PUSHED ACROSS THE REGION (INSTEAD OF OUT TO SEA AS SOME
GUIDANCE SHOWED JUST 24 HOURS AGO) BETWEEN 12Z TUESDAY AND 18Z
WEDNESDAY. THE SIZE OF THIS SLUG OF MOISTURE IS LIKELY TO BE
RELATIVELY SMALL...BUT THE AMOUNT OF MOISTURE COULD BE SUBSTANTIAL
(PWATS NEAR THE CORE LOOK TO APPROACH 1.7 INCHES)...THEREFORE THE
EXACT TRACK AND TIMING BECOME CRITICAL TO THE FORECAST THROUGH
TUESDAY/TUESDAY NIGHT. MODELS DIFFERENCES AT THIS STAGE WILL KEEP
CONFIDENCE MODERATE. THAT SAID...I DID MAKE A SOME SIGNIFICANT
CHANGES TO AREAL PRECIPITATION COVERAGE AND CHANCES THROUGH TUESDAY.
THE MAIN CHANGE WAS ADDING CHANCES FOR PRECIPITATION ACROSS MUCH OF
SAN BERNARDINO COUNTY FOR TUESDAY. I LIMITED THE CHANCES FOR THUNDER
FOR MUCH OF SAN BERNARDINO AND CLARK COUNTIES TO A SLIGHT CHANCE
BASED ON THE LIKELIHOOD OF LIMITED INSTABILITY ASSOCIATED WITH THE
SUBSTANTIAL AMOUNT OF LOW/MID-LEVEL CLOUD COVER CURRENTLY DEPICTED
WITH THIS SLUG AS IT MOVES ACROSS. ANOTHER CONCERN IS THE AMOUNT OF
AVAILABLE DEEP LAYER SHEAR...WHICH WILL RANGE FROM 30-50KTS ACROSS A
GOOD PORTION OF THE AREA. THIS COULD LEAD TO A FEW STRONGER OR MORE
ORGANIZED STORMS IF THINGS DESTABILIZE DECENTLY.
AGAIN BY ROUGHLY 18Z WEDNESDAY THIS SLUG OF ENHANCED MOISTURE SHOULD
BE RAPIDLY EXITING THE AREA...AND HAVE LEFT IN ONLY A SLIGHT CHANCE
OF SHOWERS/THUNDERSTORMS ACROSS THE NORTHEASTERN PORTION OF THE
FORECAST AREA BY WEDNESDAY AFTERNOON. BY THE EVENING...CONDITIONS
ARE LIKELY TO BE RELATIVELY DRY AREA WIDE.
FOR THURSDAY AND FRIDAY EXPECT ZONAL FLOW OR WEAK TROUGHING ACROSS
THE REGION. THIS SHOULD KEEP THINGS RELATIVELY DRY THROUGH THE END
OF THE WORK WEEK...OF NOT OCCASIONALLY BREEZY.
TEMPERATURES ARE EXPECTED TO CLIMB FROM A FEW DEGREES BELOW NORMAL
TUESDAY TO NEAR OR JUST ABOVE NORMAL BY THE END OF THE WEEK.
&&
&&
$$
UPDATE: LERICOS
SHORT TERM/AVIATION: WOLCOTT/PULLIN
LONG TERM: PULLIN
FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:
HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION
NWS MEDFORD OR
200 PM PDT SAT SEP 12 2015
.DISCUSSION...12/12Z NAM/GFS IN.
THERE ARE LOW CLOUDS AND FOG ALONG THE NORTH COAST...THE SOUTH
COAST SOUTH OF GOLD BEACH...THE COQUILLE VALLEY...AND THE EXTREME
LOWER UMPQUA THIS AFTERNOON. OTHER THAN THAT...THERE ARE SOME
MID-LEVEL AND HIGH CLOUDS OVER THE MEDFORD CWA...AND SOME CUMULUS
HAS BEGUN TO DEVELOP.
THE FLOW ALOFT IS BECOMING MORE SOUTHEASTERLY AS A LOW APPROACHES
THE COAST. SHORT WAVES ROTATING AROUND THE LOW WILL REMAIN TO THE
SOUTH OF THE FORECAST AREA. STABILITY INDICES SHOW SOME NEGATIVE
VALUES OVER THE CASCADES AND SISKIYOUS AS WELL AS PARTS OF THE
EAST SIDE...BUT THEY ARE TRENDING MORE STABLE. THERE WILL BE MORE
MOISTURE WITH PRECIPITABLE WATER VALUES INCREASING TO AROUND 1.0
INCHES...BUT IT IS ALL ELEVATED. BASES WILL BE WAY UP IN THE 10-14
KFT MSL RANGE. THERE IS ALSO SIGNIFICANT CIN AND AT LEAST TWO
STABLE LAYERS IN THE SOUNDING PROFILES. GIVEN ALL THIS...WILL
DEEMPHASIZE THUNDERSTORMS FOR TODAY. ANY THAT DO DEVELOP WILL
LIKELY BE DRY. HIGHS TODAY WILL BE 2 TO 5 DEGREES COOLER OVER THE
WEST SIDE AND NEAR THE FRIDAY HIGHS OVER THE EAST SIDE AND
NORTHERN CALIFORNIA.
BY SUNDAY THE REMNANTS OF THE UPPER LOW WILL BE OVER NORTHERN
CALIFORNIA...AND THE BEST CHANCES FOR CONVECTION LOOK TO BE OVER
SISKIYOU AND MODOC COUNTIES...CURVING UP INTO EXTREME SOUTHERN
KLAMATH AND LAKE COUNTIES. THAT`S WHERE BOTH THE NAM AND GFS
LIFTED INDICES INDICATE THE ACTION WILL BE. THE MOIST LAYER WILL
LOWER A BIT...BUT OVERALL THE STABLE LAYERS ARE STILL IN THE
SOUNDINGS AND PWATS ACTUALLY LOWER A BIT. CONVECTION STILL LOOKS
TO BE RELATIVELY HIGH-BASED...ENOUGH TO GO WITH DRY THUNDERSTORMS
AGAIN ON SUNDAY. THE COOLING TREND WILL CONTINUE WITH SUNDAY HIGHS
INLAND AROUND 10 DEGREES COOLER THAN THE SATURDAY HIGHS.
A BIG CHANGE IS IN STORE FOR MONDAY. AN INCOMING LONG WAVE TROUGH
WILL PUSH A COLD FRONT ONSHORE. INLAND MONDAY HIGHS WILL BE 10 TO
20 DEGREES COOLER THAN THE SUNDAY HIGHS. THERE WILL ALSO BE
PRECIPITATION...IT WILL BE WIDESPREAD BUT THERE WON`T BE A LOT OF
IT IN ANY ONE LOCATION. INTERMITTENT RAIN FROM THE CASCADES WEST
AND SISKIYOUS NORTH...AND SHOWERS ON THE EAST SIDE. STABILITY
REMAINS MARGINAL FOR THUNDERSTORMS. IF ANY GET GOING IT WILL BE NO
MORE THAN ISOLATED COVERAGE.
THE UPPER TROUGH WILL HEAD OFF TO THE EAST TUESDAY AND ZONAL FLOW
ALOFT WILL DEVELOP OVER THE AREA. ANOTHER TROUGH WILL MOVE
THROUGH TUESDAY NIGHT...AND THE MODELS HAVE BEEN TRENDING STRONGER
WITH THIS FEATURES. TUESDAY AND WEDNESDAY NO LONGER LOOK DRY...IT
WILL BE SHOWERY. INLAND HIGH TEMPERATURES WILL CONTINUE TO
COOL...BOTTOMING OUT WEDNESDAY 15 TO 20 DEGREES BELOW SEASONAL
NORMS.
A LONG WAVE TROUGH WILL MOVE ONSHORE THURSDAY AND MOVE OUT TO THE
EAST THURSDAY NIGHT. IT WILL PUSH A VERY WET FRONT ONSHORE
WEDNESDAY AFTERNOON INTO WEDNESDAY EVENING. THE FRONT WILL MOVE
THROUGH THE CWA WEDNESDAY NIGHT INTO THURSDAY...THEN POST- FRONTAL
SHOWERS WILL PERSIST INTO THURSDAY NIGHT. WETTING RAINS ARE LIKELY
FROM THE CASCADES WEST AND POSSIBLE OVER THE EAST SIDE. IT WILL
ALSO BE QUITE WINDY ALONG THE COAST WEDNESDAY AFTERNOON AND
EVENING AND OVER THE EAST SIDE WEDNESDAY AFTERNOON THROUGH
WEDNESDAY NIGHT. IT WON`T BE MUCH OF A COLD FRONT IN TERMS OF
TEMPERATURES THOUGH...IN FACT A WARMING TREND WILL COMMENCE ON
THURSDAY DESPITE THIS EVENT.
A LONG WAVE RIDGE WILL SLOWLY BUILD IN THURSDAY NIGHT INTO FRIDAY
AFTER THE TROUGH DEPARTS. THIS WILL TRIGGER A LOW LEVEL OFFSHORE
FLOW EVENT BEGINNING FRIDAY NIGHT AND CONTINUING THROUGH THE
WEEKEND. EXPECT DRY WEATHER AND WARMING TEMPERATURES. ON
FRIDAY...INLAND HIGH TEMPERATURES WILL BE NEAR SEASONAL
NORMS...AND THEY WILL WARM TO ABOVE NORMAL VALUES DURING THE
WEEKEND.
&&
.AVIATION...FOR THE 12/18Z TAF CYCLE...MARINE STRATUS WILL PERSIST
THROUGH TONIGHT NORTH OF CAPE BLANCO AND OFFSHORE WITH LIFR CIGS
REMAINING THE PREDOMINATE CONDITION. HOWEVER THERE IS A CHANCE FOR
BRIEF MVFR CIGS AT KOTH BETWEEN 22-0Z. MEANWHILE OFFSHORE FLOW WILL
INCREASE SOUTH OF CAPE BLANCO LATER THIS AFTERNOON AND CONTINUE
TONIGHT WITH LIFR CIGS IMPROVING TO VFR FROM CAPE BLANCO TO GOLD
BEACH BETWEEN 23-2Z. ELSEWHERE VFR CONDITIONS WILL CONTINUE FOR THE
NEXT 24 HOURS WITH ISOLATED THUNDERSTORMS POSSIBLE EAST OF THE
CASCADES AND NORTHERN CAL BETWEEN 22-3Z. -PETRUCELLI
&&
.MARINE...UPDATED 100 PM PDT SATURDAY 12 SEPTEMBER 2015...SEAS WILL
REMAIN STEEP THROUGH THIS EVENING. WINDS WILL INCREASE INTO
SUNDAY. THIS WILL PUSH SEAS TO WARNING LEVELS LATE TONIGHT SOUTH
OF CAPE BLANCO. THE GALES THERE WILL PERSIST INTO MONDAY EVENING.
A COLD FRONT ON MONDAY WILL BRING A CHANCE OF LIGHT RAIN. A
STRONGER FRONTAL SYSTEM TUESDAY THROUGH THURSDAY WILL BRING RAIN,
A POSSIBILITY OF GALES, AND SOUTHWEST SEAS THAT ARE EXPECTED TO
REACH 10 TO 15 FEET.
&&
.FIRE WEATHER...UPDATED 100 PM PDT SATURDAY 12 SEPTEMBER 2015...
CURRENT SPC ANALYSIS SHOWS VIRTUALLY NO CAPE AND LIFTED INDICES IN
THE POSITIVE TERRITORY. THE LATEST HRRR MAX REFLECTIVITY SHOWS MOST
OF THE RETURNS SOUTH OF THE FIRE WEATHER FORECAST AREA THIS
AFTERNOON, THEN LIMITED ACTIVITY SHOWING UP IN MODOC AND LAKE COUNTY
EARLY THIS EVENING. AFTER THOROUGH ANALYSIS, THE POTENTIAL FOR
ISOLATED THUNDERSTORMS INTO THIS EVENING IS MARGINAL AT BEST AND
WOULD NOT BE SURPRISED IF NOTHING HAPPENS. MODELS SHOW LITTLE OR NO
BL CAPE AND PLENTY OF CIN INTO THIS EVENING AND LIFTED INDICES
HOVERING BETWEEN 0 TO -1C. ALSO HAVE YET TO SEE ANY LIGHTNING
STRIKES IN CLOSER PROXIMITY TO THE WEAK UPPER LOW IN NORTHERN CAL.
WITH LOTS OF DRY AIR LINGERING INTO SUNDAY, WIDESPREAD HAINES 5
CONDITIONS ARE EXPECTED. WE`LL NEED TO KEEP A CLOSE EYE ON THE
NATIONAL CREEK COMPLEX, AS SOME OF THE GUIDANCE SUGGEST THERE IS A
CHANCE FOR HAINES 6 CONDITIONS THERE ON SUNDAY.
THE WEAK UPPER LOW IS NOT EXPECTED TO MOVE MUCH TONIGHT INTO SUNDAY,
IN FACT THE MODELS SUGGEST THE LOW MAY IN FACT MOVE SLIGHTLY SOUTH
ON SUNDAY AS THE NORTHERN BRANCH BEGINS TO MOVE INTO THE NORTHERN
PART OF THE REGION SUNDAY AFTERNOON WHICH IF CORRECT WOULD KEEP THE
BEST CHANCE FOR ISOLATED THUNDERSTORMS IN NORTHERN CAL FROM EASTERN
SISKIYOU COUNTY INTO MODOC COUNTY AND EXTREME SOUTHERN FIRE ZONES
624 AND 625. THUS, HAVE CONTINUED TO TREND SOUTH WITH THE ISOLATED
THUNDERSTORM POTENTIAL. OF NOTE THE SREF SHOWS A 30 PERCENT
PROBABILITY OF THUNDERSTORMS IN THE ABOVE MENTIONED AREAS AND THIS
LINES UP PRETTY WELL WITH SPC`S COVERAGE AREA FOR PROBABILITY OF
ONE STRIKE. OF NOTE THE NAM HAS BACKED OFF ON THE AMOUNT OF
INSTABILITY SUNDAY AFTERNOON IN THE ABOVE MENTIONED AREAS WITH
CAPE VALUES AROUND 300 J/KG AND LI`S AROUND -1C AT 18Z, THEN MORE
STABLE AT 0Z WITH LI`S NEAR 0C WITH NO CAPE. GIVEN THE ABOVE
MENTIONED SCENARIOS, WE`LL CONTINUE TO HEADLINE AND NOT ISSUE ANY
WATCHES.
AS WE GO INTO MONDAY GUIDANCE CONTINUES TO INDICATE SUBSTANTIAL
WETTING RAINFALL IN THE 0.10-0.25" RANGE IN SHOWERS AND ISOLATED
THUNDERSTORMS FROM ABOUT THE SCOTT VALLEY NORTHEASTWARD ACROSS THE
EAST SIDE. WINDS WILL ALSO BE STRONGER WITH MODELS SHOWING 700MB
WINDS BETWEEN 25-30 KTS. HOWEVER TEMPERATURES WILL BE DOWN AND RH`S
UP SUBSTANTIALLY, SO, WHILE A FEW NEW FIRE STARTS ARE POSSIBLE,
EXPECT THAT, OVERALL, RAIN AMOUNTS WILL BE THE MAIN STORY.
WE`LL CATCH A BREAK IN THE WEATHER TUESDAY AS ONE UPPER LEVEL TROUGH
MOVES EAST AND WEAK SHORTWAVE RIDING BUILDS IN. THEN A POTENT
FRONTAL SYSTEM IS LIKELY TO BRING SIGNIFICANT WETTING RAIN FROM THE
CASCADES WEST ON WEDNESDAY. RAINFALL AMOUNTS WILL BE LIGHTER EAST OF
THE CASCADES AND NORTHERN CAL FROM EASTERN SISKIYOU COUNTY EASTWARD
INTO MODOC COUNTY, BUT MEASURABLE RAIN IS LIKELY BY WEDNESDAY NIGHT.
COOL AND SHOWERY CONDITIONS CONTINUE THURSDAY. NOTE WHILE RAINFALL
AMOUNTS ARE EXPECTED TO BE SIGNIFICANT WEST OF THE CASCADES
WEDNESDAY INTO WEDNESDAY NIGHT, AT LEAST RELATIVE TO NORMAL FOR THIS
TIME OF THE YEAR, IT MAY ONLY BE A SEASON SLOWING EVENT BECAUSE OF
THE DEGREE OF DRYNESS WE HAVE EXPERIENCED FOR QUITE SOME TIME.
-PETRUCELLI
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
CA...NONE.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY FOR WINDS FROM 11 PM
THIS EVENING TO 11 PM PDT MONDAY FOR PZZ350-356-370-376.
SMALL CRAFT ADVISORY FROM 11 PM THIS EVENING TO 11 PM PDT MONDAY
FOR PZZ350-356.
HAZARDOUS SEAS WARNING FROM 11 PM THIS EVENING TO 11 PM PDT
MONDAY FOR PZZ350-356-370-376.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 11 PM PDT THIS
EVENING FOR PZZ350-356.
SMALL CRAFT ADVISORY UNTIL 11 PM PDT MONDAY FOR PZZ370-376.
GALE WARNING FROM 8 AM SUNDAY TO 11 PM PDT MONDAY FOR
PZZ370-376.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 2 PM PDT THIS
AFTERNOON FOR PZZ370-376.
$$
15/15/05
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
521 PM EDT SAT SEP 12 2015
.SYNOPSIS...
A SLOW MOVING FRONTAL SYSTEM WILL MOVE OFF EAST OF THE REGION
TONIGHT. THE UPPER LEVEL LOW ASSOCIATED WITH THE FRONT WILL KEEP
US UNSETTLED THROUGH SUNDAY. FAIR AND WARMER CONDITIONS WILL
RETURN BEGINNING MONDAY AND CONTINUE THROUGH MOST OR ALL OF NEXT
WEEK AS A LARGE AREA OF HIGH PRESSURE DRIFTS OVER THE OHIO VALLEY
AND MID ATLANTIC REGION.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
SURFACE LOW AS OF NOON LOOKS LIKE IT IS PRETTY MUCH ON TOP OF
JOHNSTOWN. THE WAVY FRONT EXTENDS NNE TO BETWEEN WILLIAMSPORT AND
WELLSBORO...AND SOUTH FROM THE LOW THROUGH WESTERN VIRGINIA.
LIGHTNING DATA IS STARTING TO SHOW SOME STRIKES SNEAKING INTO THE
MARYLAND BORDER COMMUNITIES OF FRANKLIN AND ADAMS COUNTIES.
WESTERN 1/4 OR SO OF MY FCST AREA HAS JUST SHOWERY PRECIPITATION
AT NOON...WHILE A STEADY MODERATE TO HEAVY RAIN IS FALLING OVER
MOST OF THE REMAINDER OF THE AREA. HRRR CONTINUES TO GENERATE NEW
RAIN OVER VIRGINIA WHICH IT SURGES NNE OVER CENTRAL AND EASTERN
ZONES THROUGH LATE AFTERNOON. OBSERVED RADAR TRENDS SUGGEST THIS
MAY BE A LITTLE TOO FAR WEST...AND THE BEST RAINS COULD TAPER OFF
LOCALLY BETWEEN 2 AND 3PM AS THE BACK EDGE SLOWLY PROPAGATES
EASTWARD.
OTHER ISSUE TO CONTEND WITH WILL BE THE POTENTIAL FOR
STRONG/SEVERE THUNDERSTORMS TO DEVELOP IN THE INCREASINGLY
UNSTABLE AIRMASS PUSHING UP INTO SERN PA. SPC HAS PLACED THE
EASTERN 1/3 OF THE STATE UNDER A MARGINAL RISK. CLOUD COVER IS
EXTENSIVE AND INSTABILITY ISN`T VERY IMPRESSIVE SO THE CHANCES
WILL NOT BE HIGH...BUT CANNOT RULE OUT AN ISOLATED STRONG STORM
TO DEVELOP IN THE INCREASINGLY HUMID ENVIRONMENT AS WIND FIELDS
INTENSIFY WITH THE APPROACH OF THE JET.
TEMPS TODAY WILL RISE ONLY VERY SLOWLY ACROSS CENTRAL AND WESTERN
PA THIS MORNING. WARMEST TEMPS TODAY WILL BE OVER THE SUSQ VALLEY
WHERE HIGHS WILL REACH THE LOW TO MID 70S...WHILE THE NW MTNS AND
LAUREL HIGHLANDS SEE THE MERCURY HOLD BETWEEN 59-62F.
HAVE MODIFIED POPS AND STORM TOTAL RAINFALL SLIGHTLY...BUT STILL
FEEL THAT MODEL CONSENSUS STILLS POINTS TWD A BENEFICIAL AMOUNT
OF .50" TO 1.00" INCHES ACROSS THE REGION BY LATE TONIGHT.
SHORT RANGE OPERATIONAL MODELS AGREE WITH THE STEADY RAIN TAPERING
OFF QUICKLY THIS EVENING...WITH JUST SCATTERED SHOWERS REMAINING
FOR MUCH OF THE OVERNIGHT. THIS WILL PROMPT AN OVERALL LOWERING OF
THE POPS...WITH THE HIGHEST CHANCES CONFINED TO MY WESTERN AND
NORTHER HIGHER ELEVATIONS.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/...
THE UPPER LOW AND TROUGH WILL BE SWINGING THROUGH DURING THE DAY
SUNDAY. COLD AIR ALOFT WILL HELP DESTABILIZE THE ATMOSPHERE
LEADING TO THE CHANCE OF A FEW POP UP SHOWERS...AND WITH TOTAL-
TOTALS TICKLING 50...WOULDN`T BE SURPRISED TO SEE SOME LOW TOPPED
THUNDER AND PEA SIZED HAIL. A GRADUALLY INCREASING NW BREEZE WILL
DEVELOP LATE TONIGHT AND SUNDAY WITH WIND GUSTS OF 15-25 MPH FROM
THE NW EXPECTED DURING THE DAY SUNDAY.
HIGHS AVERAGING IN THE 60S WILL BE SOME 5-10 DEG COOLER THAN
NORMAL FOR THE SECOND WEEK OF SEPTEMBER.
&&
.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
SOME LINGERING SHOWERS ARE POSSIBLE VERY EARLY IN THE EXTENDED
PERIOD AS THE UPPER LOW PUSHES NORTHEAST OF THE AREA SUNDAY NIGHT.
MONDAY WILL BE DRY BUT STILL COOLER...WITH A SURFACE HIGH
ANCHORED SOUTH OF PENNSYLVANIA AND RESULTANT NORTHWEST FLOW OVER
CENTRAL PA.
AFTER THAT...RIDGING BUILDS OVER THE EASTERN HALF OF THE COUNTRY AND
THE CENTER OF THE SURFACE HIGH SHIFTS NORTH...BRINGING CONTINUED DRY
CONDITIONS AND WARMING TEMPERATURES. BY MIDWEEK HIGHS WILL CLIMB
ABOVE SEASONAL NORMALS.
THIS EXTENDED PERIOD OF DRY WEATHER SHOULD LAST THROUGH THE END OF
THE WORK WEEK...BEFORE A SHORTWAVE APPROACHES FROM THE GREAT LAKES
AND BRINGS THE NEXT CHANCE FOR RAIN TO CENTRAL PA NEXT WEEKEND.
&&
.AVIATION /21Z SATURDAY THROUGH THURSDAY/...
BACK EDGE OF THE HEAVIER RAIN MOVED A TAD FASTER THIS AFT
THAN THE 00Z MODELS SHOWED LAST NIGHT. STILL SOME HEAVY
AMTS WITH GUSTY WINDS EARLIER ACROSS THE SE.
ADJUSTED TAFS SEVERAL TIMES SINCE I STARTED AT 4 PM.
MORE ADJUSTMENTS MADE TO 21Z TAF PACKAGE.
EARLIER DISCUSSION BELOW.
THE SURFACE COLD FRONT WILL EDGE SLOWLY EAST ACROSS PA
TODAY...MOVING EAST OF THE REGION OVERNIGHT. WIDESPREAD IFR/MVFR
WILL DOMINATE INTO THE OVERNIGHT.
THERE COULD BE ENOUGH INSTABILITY THAT AN ISOLATED THUNDERSTORM
CANNOT BE RULED OUT OVER THE SOUTHERN AND ESPECIALLY SOUTHEASTERN
AREAS THROUGH LATE AFTERNOON.
RAIN WILL TAPER TO SHOWERS THIS EVENING AS THE MAIN WAVE BEGINS
TO EXIT...BUT EXPECT WIDESPREAD IFR/MVFR TO CONTINUE AS THE UPPER
LOW MOVES OVER THE AREA.
AS TROUGH LIFTS TO THE NE....MUCH OF SUNDAY WILL FEATURE GUSTY
WINDS...MVFR CONDITIONS AND SHOWERS...MOST NUMEROUS IN THE NW.
CANNOT RULE OUT A GUSTY THUNDERSTORM AS WELL.
OUTLOOK...
MON-THU...SCT MORNING VALLEY FOG...OTHERWISE VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...LA CORTE
SHORT TERM...LA CORTE
LONG TERM...LA CORTE/HAGNER
AVIATION...LA CORTE/MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
316 PM EDT SAT SEP 12 2015
.SYNOPSIS...
A SLOW MOVING FRONTAL SYSTEM WILL MOVE OFF EAST OF THE REGION
TONIGHT. THE UPPER LEVEL LOW ASSOCIATED WITH THE FRONT WILL KEEP
US UNSETTLED THROUGH SUNDAY. FAIR AND WARMER CONDITIONS WILL
RETURN BEGINNING MONDAY AND CONTINUE THROUGH MOST OR ALL OF NEXT
WEEK AS A LARGE AREA OF HIGH PRESSURE DRIFTS OVER THE OHIO VALLEY
AND MID ATLANTIC REGION.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
SURFACE LOW AS OF NOON LOOKS LIKE IT IS PRETTY MUCH ON TOP OF
JOHNSTOWN. THE WAVY FRONT EXTENDS NNE TO BETWEEN WILLIAMSPORT AND
WELLSBORO...AND SOUTH FROM THE LOW THROUGH WESTERN VIRGINIA.
LIGHTNING DATA IS STARTING TO SHOW SOME STRIKES SNEAKING INTO THE
MARYLAND BORDER COMMUNITIES OF FRANKLIN AND ADAMS COUNTIES.
WESTERN 1/4 OR SO OF MY FCST AREA HAS JUST SHOWERY PRECIPITATION
AT NOON...WHILE A STEADY MODERATE TO HEAVY RAIN IS FALLING OVER
MOST OF THE REMAINDER OF THE AREA. HRRR CONTINUES TO GENERATE NEW
RAIN OVER VIRGINIA WHICH IT SURGES NNE OVER CENTRAL AND EASTERN
ZONES THROUGH LATE AFTERNOON. OBSERVED RADAR TRENDS SUGGEST THIS
MAY BE A LITTLE TOO FAR WEST...AND THE BEST RAINS COULD TAPER OFF
LOCALLY BETWEEN 2 AND 3PM AS THE BACK EDGE SLOWLY PROPAGATES
EASTWARD.
OTHER ISSUE TO CONTEND WITH WILL BE THE POTENTIAL FOR
STRONG/SEVERE THUNDERSTORMS TO DEVELOP IN THE INCREASINGLY
UNSTABLE AIRMASS PUSHING UP INTO SERN PA. SPC HAS PLACED THE
EASTERN 1/3 OF THE STATE UNDER A MARGINAL RISK. CLOUD COVER IS
EXTENSIVE AND INSTABILITY ISN`T VERY IMPRESSIVE SO THE CHANCES
WILL NOT BE HIGH...BUT CANNOT RULE OUT AN ISOLATED STRONG STORM TO
DEVELOP IN THE INCREASINGLY HUMID ENVIRONMENT AS WIND FIELDS
INTENSIFY WITH THE APPROACH OF THE JET.
TEMPS TODAY WILL RISE ONLY VERY SLOWLY ACROSS CENTRAL AND WESTERN
PA THIS MORNING. WARMEST TEMPS TODAY WILL BE OVER THE SUSQ VALLEY
WHERE HIGHS WILL REACH THE LOW TO MID 70S...WHILE THE NW MTNS AND
LAUREL HIGHLANDS SEE THE MERCURY HOLD BETWEEN 59-62F.
HAVE MODIFIED POPS AND STORM TOTAL RAINFALL SLIGHTLY...BUT STILL
FEEL THAT MODEL CONSENSUS STILLS POINTS TWD A BENEFICIAL AMOUNT
OF .50" TO 1.00" INCHES ACROSS THE REGION BY LATE TONIGHT.
SHORT RANGE OPERATIONAL MODELS AGREE WITH THE STEADY RAIN TAPERING
OFF QUICKLY THIS EVENING...WITH JUST SCATTERED SHOWERS REMAINING
FOR MUCH OF THE OVERNIGHT. THIS WILL PROMPT AN OVERALL LOWERING OF
THE POPS...WITH THE HIGHEST CHANCES CONFINED TO MY WESTERN AND
NORTHER HIGHER ELEVATIONS.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/...
THE UPPER LOW AND TROUGH WILL BE SWINGING THROUGH DURING THE DAY
SUNDAY. COLD AIR ALOFT WILL HELP DESTABILIZE THE ATMOSPHERE
LEADING TO THE CHANCE OF A FEW POP UP SHOWERS...AND WITH TOTAL-
TOTALS TICKLING 50...WOULDN`T BE SURPRISED TO SEE SOME LOW TOPPED
THUNDER AND PEA SIZED HAIL. A GRADUALLY INCREASING NW BREEZE WILL
DEVELOP LATE TONIGHT AND SUNDAY WITH WIND GUSTS OF 15-25 MPH FROM
THE NW EXPECTED DURING THE DAY SUNDAY.
HIGHS AVERAGING IN THE 60S WILL BE SOME 5-10 DEG COOLER THAN
NORMAL FOR THE SECOND WEEK OF SEPTEMBER.
&&
.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
SOME LINGERING SHOWERS ARE POSSIBLE VERY EARLY IN THE EXTENDED
PERIOD AS THE UPPER LOW PUSHES NORTHEAST OF THE AREA SUNDAY NIGHT.
MONDAY WILL BE DRY BUT STILL COOLER...WITH A SURFACE HIGH
ANCHORED SOUTH OF PENNSYLVANIA AND RESULTANT NORTHWEST FLOW OVER
CENTRAL PA.
AFTER THAT...RIDGING BUILDS OVER THE EASTERN HALF OF THE COUNTRY AND
THE CENTER OF THE SURFACE HIGH SHIFTS NORTH...BRINGING CONTINUED DRY
CONDITIONS AND WARMING TEMPERATURES. BY MIDWEEK HIGHS WILL CLIMB
ABOVE SEASONAL NORMALS.
THIS EXTENDED PERIOD OF DRY WEATHER SHOULD LAST THROUGH THE END OF
THE WORK WEEK...BEFORE A SHORTWAVE APPROACHES FROM THE GREAT LAKES
AND BRINGS THE NEXT CHANCE FOR RAIN TO CENTRAL PA NEXT WEEKEND.
&&
.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
THE SURFACE COLD FRONT WILL EDGE SLOWLY EAST ACROSS PA
TODAY...MOVING EAST OF THE REGION OVERNIGHT. WIDESPREAD IFR/MVFR
WILL DOMINATE INTO THE OVERNIGHT.
THERE COULD BE ENOUGH INSTABILITY THAT AN ISOLATED THUNDERSTORM
CANNOT BE RULED OUT OVER THE SOUTHERN AND ESPECIALLY SOUTHEASTERN
AREAS THROUGH LATE AFTERNOON.
RAIN WILL TAPER TO SHOWERS THIS EVENING AS THE MAIN WAVE BEGINS
TO EXIT...BUT EXPECT WIDESPREAD IFR/MVFR TO CONTINUE AS THE UPPER
LOW MOVES OVER THE AREA.
AS TROUGH LIFTS TO THE NE....MUCH OF SUNDAY WILL FEATURE GUSTY
WINDS...MVFR CONDITIONS AND SHOWERS...MOST NUMEROUS IN THE NW.
CANNOT RULE OUT A GUSTY THUNDERSTORM AS WELL.
OUTLOOK...
MON-THU...SCT MORNING VALLEY FOG...OTHERWISE VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...LA CORTE
SHORT TERM...LA CORTE
LONG TERM...HAGNER
AVIATION...LA CORTE
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
220 PM EDT SAT SEP 12 2015
.SYNOPSIS...
A SLOW MOVING FRONTAL SYSTEM WILL MOVE OFF EAST OF THE REGION
TONIGHT. THE UPPER LEVEL LOW ASSOCIATED WITH THE FRONT WILL KEEP
US UNSETTLED THROUGH SUNDAY. FAIR AND WARMER CONDITIONS WILL
RETURN BEGINNING MONDAY AND CONTINUE THROUGH MOST OR ALL OF NEXT
WEEK AS A LARGE AREA OF HIGH PRESSURE DRIFTS OVER THE OHIO VALLEY
AND MID ATLANTIC REGION.
&&
.NEAR TERM /THROUGH TONIGHT/...
SURFACE LOW AS OF NOON LOOKS LIKE IT IS PRETTY MUCH ON TOP OF
JOHNSTOWN. THE WAVY FRONT EXTENDS NNE TO BETWEEN WILLIAMSPORT AND
WELLSBORO...AND SOUTH FROM THE LOW THROUGH WESTERN VIRGINIA.
LIGHTNING DATA IS STARTING TO SHOW SOME STRIKES SNEAKING INTO THE
MARYLAND BORDER COMMUNITIES OF FRANKLIN AND ADAMS COUNTIES.
WESTERN 1/4 OR SO OF MY FCST AREA HAS JUST SHOWERY PRECIPITATION
AT NOON...WHILE A STEADY MODERATE TO HEAVY RAIN IS FALLING OVER
MOST OF THE REMAINDER OF THE AREA. HRRR CONTINUES TO GENERATE NEW
RAIN OVER VIRGINIA WHICH IT SURGES NNE OVER CENTRAL AND EASTERN
ZONES THROUGH LATE AFTERNOON. OBSERVED RADAR TRENDS SUGGEST THIS
MAY BE A LITTLE TOO FAR WEST...AND THE BEST RAINS COULD TAPER OFF
LOCALLY BETWEEN 2 AND 3PM AS THE BACK EDGE SLOWLY PROPAGATES
EASTWARD.
OTHER ISSUE TO CONTEND WITH WILL BE THE POTENTIAL FOR
STRONG/SEVERE THUNDERSTORMS TO DEVELOP IN THE INCREASINGLY
UNSTABLE AIRMASS PUSHING UP INTO SERN PA. SPC HAS PLACED THE
EASTERN 1/3 OF THE STATE UNDER A MARGINAL RISK. CLOUD COVER IS
EXTENSIVE AND INSTABILITY ISN`T VERY IMPRESSIVE SO THE CHANCES
WILL NOT BE HIGH...BUT CANNOT RULE OUT AN ISOLATED STRONG STORM TO
DEVELOP IN THE INCREASINGLY HUMID ENVIRONMENT AS WIND FIELDS
INTENSIFY WITH THE APPROACH OF THE JET.
TEMPS TODAY WILL RISE ONLY VERY SLOWLY ACROSS CENTRAL AND WESTERN
PA THIS MORNING. WARMEST TEMPS TODAY WILL BE OVER THE SUSQ VALLEY
WHERE HIGHS WILL REACH THE LOW TO MID 70S...WHILE THE NW MTNS AND
LAUREL HIGHLANDS SEE THE MERCURY HOLD BETWEEN 59-62F.
HAVE MODIFIED POPS AND STORM TOTAL RAINFALL SLIGHTLY...BUT STILL
FEEL THAT MODEL CONSENSUS STILLS POINTS TWD A BENEFICIAL AMOUNT
OF .50" TO 1.00" INCHES ACROSS THE REGION BY LATE TONIGHT.
SHORT RANGE OPERATIONAL MODELS AGREE WITH THE STEADY RAIN TAPERING
OFF QUICKLY THIS EVENING...WITH JUST SCATTERED SHOWERS REMAINING
FOR MUCH OF THE OVERNIGHT. THIS WILL PROMPT AN OVERALL LOWERING OF
THE POPS...WITH THE HIGHEST CHANCES CONFINED TO MY WESTERN AND
NORTHER HIGHER ELEVATIONS.
&&
.SHORT TERM /SUNDAY/...
THE UPPER LOW AND TROUGH WILL BE SWINGING THROUGH DURING THE DAY
SUNDAY. COLD AIR ALOFT WILL HELP DESTABILIZE THE ATMOSPHERE
LEADING TO THE CHANCE OF A FEW POP UP SHOWERS...AND WITH TOTAL-
TOTALS TICKLING 50...WOULDN`T BE SURPRISED TO SEE SOME LOW TOPPED
THUNDER AND PEA SIZED HAIL. A GRADUALLY INCREASING NW BREEZE WILL
DEVELOP LATE TONIGHT AND SUNDAY WITH WIND GUSTS OF 15-25 MPH FROM
THE NW EXPECTED DURING THE DAY SUNDAY.
HIGHS AVERAGING IN THE 60S WILL BE SOME 5-10 DEG COOLER THAN
NORMAL FOR THE SECOND WEEK OF SEPTEMBER.
&&
.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
THE BULK OF THE SENSIBLE WEATHER WILL OCCUR VERY EARLY IN THIS
EXTENDED FCST PERIOD AS WE EXPERIENCE THE EFFECTS OF THE UPPER
TROUGH CLOSING OFF AS IT DROPS THROUGH THE EASTERN GR LAKES AND
EVENTUALLY MOVES OVERHEAD.
ENSEMBLES INDICATE THE RAIN TAPERING TO SHOWERS AND ENDING SUNDAY
NIGHT. THIS WILL SET THE STAGE FOR ANOTHER EXTENDED PERIOD OF DRY
WEATHER WHICH SHOULD LAST THROUGH THE END OF THE WORK WEEK AND
POSSIBLY INTO THE WEEKEND AS THE MEAN UPPER RIDGE IS PROJECTED TO
SURGE BACK INTO THE NERN US.
GEFS AND ECMWF HINT AT SHORTWAVE ENERGY BEGINNING TO CHEW THE TOP
OFF THE RIDGE BY NEXT WEEKEND WHICH LEADS TO THE MENTION OF A
SMALL CHANCE OF SHOWERS...BUT CONFIDENCE IS LOW THIS FAR OUT.
UNTIL THEN IT LOOKS LIKE ANOTHER BOUT OF LATE SUMMER WARMTH ON THE
WAY.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
THE SURFACE COLD FRONT WILL EDGE SLOWLY EAST ACROSS PA
TODAY...MOVING EAST OF THE REGION OVERNIGHT. WIDESPREAD IFR/MVFR
WILL DOMINATE INTO THE OVERNIGHT.
THERE COULD BE ENOUGH INSTABILITY THAT AN ISOLATED THUNDERSTORM
CANNOT BE RULED OUT OVER THE SOUTHERN AND ESPECIALLY SOUTHEASTERN
AREAS THROUGH LATE AFTERNOON.
RAIN WILL TAPER TO SHOWERS THIS EVENING AS THE MAIN WAVE BEGINS
TO EXIT...BUT EXPECT WIDESPREAD IFR/MVFR TO CONTINUE AS THE UPPER
LOW MOVES OVER THE AREA.
AS TROUGH LIFTS TO THE NE....MUCH OF SUNDAY WILL FEATURE GUSTY
WINDS...MVFR CONDITIONS AND SHOWERS...MOST NUMEROUS IN THE NW.
CANNOT RULE OUT A GUSTY THUNDERSTORM AS WELL.
OUTLOOK...
MON-THU...SCT MORNING VALLEY FOG...OTHERWISE VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...LA CORTE
SHORT TERM...LA CORTE
LONG TERM...LA CORTE
AVIATION...LA CORTE
AREA FORECAST DISCUSSION
NWS CORPUS CHRISTI TX
244 PM CDT SAT SEP 12 2015
.SHORT TERM (TONIGHT THROUGH SUNDAY NIGHT)...THE TREND THROUGH THE
SHORT TERM WILL BE DRIER AIR MOVING INTO SOUTH TEXAS. PRIOR TO
THIS THOUGH...ISOLATED SHOWERS WILL CONTINUE THIS AFTERNOON
ACROSS THE GULF WATERS AND SOUTHERN/WESTERN SECTIONS OF THE CWA.
LATEST RUN OF THE HRRR SUPPORTS THIS AND WILL KEEP 20 POPS FOR
THESE AREAS THROUGH 00Z. PLEASANT CONDITIONS CAN BE EXPECTED
TONIGHT WITH LOWS FALLING INTO THE MIDDLE 60S ACROSS THE NORTH
WITH LOWER 70S ELSEWHERE. DRY AIRMASS WILL BE ENTRENCHED ACROSS
SOUTH TEXAS BY SUNDAY AS PW VALUES FALL BELOW 1.5 INCHES. HIGHS
WILL STILL BE ABLE TO CLIMB INTO THE UPPER 80S ACROSS THE EAST
WITH LOWER 90S TOWARDS THE RIO GRANDE PLAINS. SIMILAR TEMPERATURES
TO TONIGHT ARE ALSO ANTICIPATED ON SUNDAY NIGHT.
&&
.LONG TERM (MONDAY THROUGH SATURDAY)...THE PERIOD WILL BEGIN MOSTLY
DRY AS THE DRIER AIRMASS INVADING THE AREA TODAY REMAINS IN PLACE.
THEREAFTER DEEP MSTR WILL INCREASE AS EASTERLY FLOW STRENGTHENS AND
A WEAK COASTAL TROUGH DEVELOPS. CHC POPS WILL BE CONTINUED NEAR THE
COAST AND OFFSHORE THROUGH THE MIDDLE AND END OF THE WORKWEEK WITH
LOWER POPS WEST. MID LEVEL RIDGING STRENGTHENS LATE WEEK AND INTO
THE WEEKEND SO POPS WILL BE CONFINED TO THE FAVORED SEABREEZE AREAS.
MEX TEMPERATURES LOOK TOO WARM ACRS THE BOARD...ESPLY IN LIGHT OF
RECENT RAINS AND HV UNDERCUT.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 70 90 71 89 74 / 0 0 0 10 20
VICTORIA 64 87 65 88 69 / 0 0 0 10 10
LAREDO 72 93 71 95 73 / 0 0 0 10 0
ALICE 69 91 68 92 72 / 0 0 0 10 10
ROCKPORT 71 88 73 87 77 / 0 0 0 10 20
COTULLA 69 93 69 94 71 / 0 0 0 0 0
KINGSVILLE 69 90 70 91 73 / 0 0 0 10 10
NAVY CORPUS 75 87 74 87 77 / 0 0 0 10 20
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
TB/78...SHORT TERM
TJ/70...LONG TERM