Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 09/20/12
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
204 PM EDT TUE SEP 18 2012
.SYNOPSIS...
SLOW MOVING, BUT POTENT, COLD FRONT WILL SWEEP THROUGH THE REGION
LATER TONIGHT AS THE PARENT LOW PRESSURE SYSTEM MOVES TO OUR
NORTHEAST. HIGH PRESSURE WILL BUILD IN FROM THE NORTH LATER ON
WEDNESDAY THROUGH FRIDAY. ANOTHER COLD FRONT LOOKS TO PUSH THROUGH
OUR REGION LATE IN THE DAY ON SATURDAY WITH HIGH PRESSURE ONCE
AGAIN FILLING IN BEHIND IT LATER ON SUNDAY INTO MONDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LOOKING AT THE 12Z SFC ANALYSIS AND UPPER AIR PATTERN. AS MY MID
SHIFT PREDECESSOR HAS BEEN SAYING FOR DAYS WE STILL HAVE AN
UNPHASED SYSTEM APPROACHING FROM THE WEST. IT LOOKS AS THOUGH MOST
OF THE ACTION WILL BE FROM THE SOUTHERN STREAM SYSTEM WITH THE
SECOND FRONT MAYBE PROLONGING LIGHTER RAIN CHANCES DEEPER INTO THE
NIGHT.
EVEN WITHOUT THE PHASING THERE IS SFC BASED INSTABILITY AND KDIX
AND KDOX VMP ARE BOTH SHOWING 50KTS OF WIND ALRDY AT 3K. THE HI
RES WRF-NMM EAST IS SHOWING THE BEST DEPICTION OF ONOGING
CONVECTION, BOTH THE HRRR AND COSPA SEEM TOO HOT TOO EAST TOO
FAST. WE HAVE CLOUDED OVER WHICH WOULD REDUCE INSTABILITY A BIT,
BUT ITS NOT ENOUGH. SO WE WILL WAIT FOR ORGANIZATION TO ENHANCE
THE POTENTIAL FOR SEVERE WEATHER AND FOLLOWING THE WRF-NMM-E FOR
NOW AS HIEST IMPACT TIME.
THE HEAVIEST RAIN HAS FALLEN SO FAR NORTH AND WEST WHERE FFG IS
HIGH, SO UNLESS THERE IS TRAINING, SO FAR SO GOOD.
IF WE DID NOT HAVE THE TOPOGRAPHY NW, WE ARE TEMPTED TO DROP THE
ADVISORY THERE, BUT WITH THE HIER TERRAIN, WE WILL KEEP IT GOING.
HIEST CONFIDENCE OUTSIDE OF CONVECTION REMAINS EAST FOR WIND ADVY
GUSTS. NO BIG CHANGES TO TEMPS AND DEW POINTS.
AS HAS BEEN NOTED IN PREVIOUS DISCUSSIONS, TODAY LOOKS TO BE AN
ACTIVE DAY. THE MODELS STILL SUPPORT THE HEAVY RAIN CONCERN
ESPECIALLY AS ONE MOVES NORTHWEST THROUGH THE FORECAST AREA. THE
ISENTROPIC LIFT RAIN OCCURRING EARLY THIS MORNING WAS MODERATE IN
NATURE, AND THE WATER VAPOR IMAGERY ALONG WITH SURFACE AND H8 DEW
POINTS AND H7 THETA E VALUES CONFIRM THAT MOISTURE IS DEEP. WE
START WITH HIGH FFG AND FFH VALUES (THE MOST VULNERABLE PLACES ARE
FAR NORTHERN NEW JERSEY AND THE AREA IN AND NEAR URBANIZED PARTS
OF THE DELAWARE VALLEY), BUT PLACES WHERE CONVECTION (ONCE IT
DEVELOPS) HITS HARDEST LIKELY WILL SEE SOME KIND OF FLOOD ADVISORY
OR WARNING. OUR QPF FOR TODAY THROUGH TONIGHT RANGES FROM A BIT
OVER AN INCH SOUTHEAST TO ALMOST 2.5 INCHES NORTHWEST, BUT LOCALES
HARD HIT BY CONVECTION COULD SEE IN EXCESS OF 4 INCHES ANYWHERE IN
THE FORECAST AREA.
REGARDING CONVECTION, THE DYNAMICS TO SUPPORT IT DEVELOP DURING THE
COURSE OF THE DAY WITH THE ADVANCING UPPER JET, A MID LEVEL IMPULSE
THAT WAS THE ROBUST TEXAS WAVE MOVING UP FROM THE SOUTHWEST, AND
GOOD MID LEVEL Q-VECTOR CONVERGENCE. LOWER LEVEL FRONTOGENESIS
INCREASES AS THE COLD FRONT APPROACHES, AND HELICITY BECOMES VERY
ROBUST AS A STRONG LOW LEVEL JET APPROACHES. THE LIMITING FACTOR
WOULD BE INSTABILITY. THERE IS ENOUGH ALOFT FOR SOME LOW TOP
CONVECTION TO DEVELOP, AND IT WOULD REQUIRE A BREAK BETWEEN THE
ISENTROPIC LIFT RAIN AND THE CONVECTIVE RAIN FOR US TO WARM
SUFFICIENTLY TO TAP THAT INSTABILITY AT THE SURFACE AND DEVELOP
STRONG TO SEVERE STORMS. THAT IS A POSSIBILITY, AND SPC MAINTAINS
OUR AREA IN A SLIGHT RISK.
REGARDING WINDS OUTSIDE OF CONVECTION, IT ALSO IS THE CASE THAT WE
WOULD HAVE TO WARM SUFFICIENTLY AT THE SURFACE TO MIX THE STRONG
WINDS AT ABOUT H950 DOWN. THE NAM SAYS WE WILL, ALTHOUGH THE GFS
DOES NOT. THE ADVISORY LIKELY STANDS A BETTER CHANCE VERIFYING
SOUTHEAST THAN NORTHWEST (EXCEPT FOR OUR HIGHER ELEVATIONS
NORTHWEST), BECAUSE THE CHANCES OF A SIGNIFICANT BREAK IN RAIN AND
CLOUDS IS HIGHER THERE. WE ARE NOT CONFIDENT ENOUGH TO TRIM THE
ADVISORY GEOGRAPHICALLY AT THIS POINT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM WEDNESDAY/...
THE COLD FRONT AND MOST OF THE SUPPORT ALOFT MOVE THROUGH THE AREA
FROM LATE EVENING NORTHWEST TO AFTER MIDNIGHT SOUTHEAST (THE HIGHER
ONE GOES, THE MORE THE KINEMATICS AND DYNAMICS HANG BACK WITH THE
UPPER JET JUST INTO OUR WESTERN ZONES AROUND DAYBREAK). THE FRONT
SHOULD TAKE THE WINDS AND THE CONVECTION (POSSIBLY STRONG) WITH
HEAVY RAIN WITH IT, ALTHOUGH THERE MAY BE SOME REAR INFLOW RAINFALL
BEHIND THE FRONT THAT WOULD BE ENHANCED (AS THE PREVIOUS LONG TERM
FORECASTER NOTED) BY TRAILING FRONTOGENETIC FORCING AND THE UPPER
JET. SINCE WINDS ALOFT ARE STRONGEST NEAR THE COLD FRONT, WE DID NOT
CHANGE THE ADVISORY TIMING AT THIS POINT ALTHOUGH IT MAY BE MORE
DIFFICULT TO MIX WINDS DOWN OUTSIDE OF CONVECTION AFTER DUSK.
GUIDANCE AND CONTINUITY WERE RELIED ON FOR MINIMUM TEMPERATURES IN
THIS DYNAMIC PERIOD.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
5-WAVE MODEL GUIDANCE SHOWS MID-LEVEL RIDGING TO OUR EAST WITH A
LONGWAVE TROUGH TO OUR IMMEDIATE WEST WITH ANOTHER RIDGE OVER THE
WESTERN UNITED STATES. THE RIDGE TO OUR EAST WILL NOT ALLOW MUCH
WEST-EAST PROGRESSION OF THE TROUGH OVER THE MID-WEST WHICH KEEPS
OUR SENSIBLE WEATHER DRY BUT A TAD COOLER THAN NORMAL WITH AN
ONSHORE FLOW ESTABLISHING ITSELF BY THURSDAY. THE BLOCKY PATTERN
WILL ALSO KEEP THE COLD FRONT THAT MOVED THROUGH LATE TUESDAY NIGHT
CLOSER TO THE COAST WHICH COULD PLAY A FACTOR IN A BIT MORE CLOUD
COVER THAN CURRENTLY FORECASTED.
DRYING TREND WILL CONTINUE THROUGH THE EARLY PART OF WEDNESDAY AS
THE POTENT COLD FRONT PUSHES FURTHER OFFSHORE, BUT AS WAS SAID
ABOVE, GETS HUNG UP A BIT. A BRISK NORTH-NORTHWEST WIND KICKS IN AND
REALLY BEGINS TO COOL THE COLUMN. 850MB TEMPERATURES DROP TO NEAR
5-6C AND IF WE ARE ABLE TO MIX UP TO THAT LEVEL ADIABATICALLY, THAT
WOULD YIELD MAXIMUM TEMPERATURES AROUND 71F...WELL BELOW NORMAL. THE
STAT GUIDANCE SUGGESTED TEMPERATURES WOULD BE A BIT WARMER THAN THIS
WHICH SEEMS COMPLETELY PROBABLE GIVEN A MINOR DOWNSLOPING COMPONENT
TOMORROW AFTERNOON UNDER AMPLE SUNSHINE.
THE STRONGER FLOW WEAKENS AS HIGH PRESSURE TO OUR NORTHWEST SLOWLY
BUILDS IN ON THURSDAY GIVING US MORE OF AN ONSHORE WIND. OCEAN
TEMPERATURES RANGING FROM THE LOW TO MID-70S SHOULD PERMIT DAYTIME
MAXES IN THE MID TO UPPER 70S, MAINLY INTERIOR AREAS, ON BOTH
THURSDAY AND FRIDAY...PLENTY OF SUNSHINE BOTH DAYS TOO. THIS HIGH
THEN SLIDES TO OUR EAST AND SETS UP A WEAK RETURN FLOW ON SATURDAY.
ENERGY ACROSS THE UPPER MID-WEST DIVES INTO THE STUCK LONGWAVE
TROUGH TO OUR WEST AND BEGINS TO NUDGE IT TOWARDS THE EAST. THIS
MID-LEVEL WAVE THEN DROPS A COLD FRONT THROUGH OUR REGION BY LATER
ON SATURDAY INTO SUNDAY MORNING. THIS IS OUR NEXT CHANCE AT
UNSETTLED WEATHER...TIMING IS STILL IN QUESTION DUE TO HOW STRONG
THE ENERGY DIVING INTO THE BASE OF THE TROUGH ACTUALLY IS AND
THEREFORE HOW FAST IT PUSHING IT EAST. FOR THE TIME BEING MAINTAINED
CHANCE POPS ON SATURDAY AND PART OF SUNDAY AND THEN DRY OUT MONDAY
WITH HIGH PRESSURE NEARING. TEMPERATURES WILL ALSO FALL BACK BELOW
NORMAL ON SUNDAY AND MONDAY BEHIND THE SECOND COLD FRONTAL PASSAGE.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
HEAVY RAIN ASSOCIATED WITH AN APPROACHING STORM SYSTEM WILL CONTINUE
TO SPREAD EAST ACROSS THE TAF SITES THIS AFTERNOON INTO THIS
EVENING. CONDITIONS ARE MOSTLY VFR OR MVFR EARLY THIS AFTERNOON, BUT
AS THE SHOWERS SPREAD EASTWARD, CONDITIONS WILL DETERIORATE. AS THE
HEAVIEST LINE OF SHOWERS, AND POSSIBLE THUNDERSTORMS, REACHES THE
AREA LATER THIS AFTERNOON/THIS EVENING, THE TERMINALS WILL LIKELY
BECOME IFR FOR A PERIOD OF TIME. THERE ARE ACTUALLY TWO FRONTS THAT
ARE MOVING TOWARD THE AREA; THE FIRST HAS THE HEAVY RAINFALL, LOW
CIG/VSBY CONDITIONS, AND WIND A WIND SHIFT, AND WILL SLOWLY MOVE
ACROSS THE TAF SITES AROUND 22-02Z FROM WEST TO EAST. THE SECOND
FRONT WILL CROSS THE AREA OVERNIGHT, AND WILL HAVE ANOTHER WIND
SHIFT WITH NORTHWEST WINDS TO FOLLOW; ALSO, WINDS ARE EXPECTED TO
DIMINISH BEHIND THE SECOND FRONT. AHEAD AND ALONG THE INITIAL
FRONT, WINDS WILL CONTINUE TO GUST IN THE UPPER 20S TO MID 30S.
ON WEDNESDAY, WINDS MAY BE A BIT GUSTY EARLY IN THE DAY ONCE WE
BEGIN TO MIX-OUT BY MID-MORNING, BUT THE WINDS GUSTS WILL LIKELY
DIMINISH THROUGH THE AFTERNOON. VFR CONDITIONS SHOULD PREVAIL FOR
THE ENTIRE DAY.
OUTLOOK...
THURSDAY - FRIDAY...VFR CONDITIONS EXPECTED. WINDS TURN MORE NORTH-
NORTHEAST ON THURSDAY AND FRIDAY. POSSIBLE MVFR VSBYS IN THE EARLY
MORNING HOURS OUTSIDE OF THE PHL METRO AREA.
SATURDAY...STARTS OFF VFR WITH POSSIBLE MVFR CIGS AND VSBYS AS COLD
FRONT SLIDES THROUGH LATER IN THE DAY. SCATTERED SHOWERS ALSO
POSSIBLE.
&&
.MARINE...
GALES WERE STARTED AT THE PRESENT AS WE ARE STARTING TO SEE SOME
GALE FORCE GUSTS.
WE MAINTAIN THE GALE WARNING AS IT WAS. WATER TEMPERATURES NEAR 25 C
STAND A FAIR CHANCE OF TAPPING THE STRONG WINDS EXPECTED TO DEVELOP
AT AROUND 1500 FT. THE COLD FRONT WILL CROSS THE WATERS WELL AFTER
MIDNIGHT TONIGHT, AND THAT WILL END THE GALES. SEAS OF UP TO 10 OR
11 FT ARE FORECAST FOR THE OCEAN AND SEAS OF UP TO 6 FT ARE FORECAST
FOR THE BAY WHILE THE GALES OCCUR.
OUTLOOK...
NORTHWEST WINDS WILL REMAIN QUITE GUSTY ON WEDNESDAY AT AROUND 25
KNOTS, ULTIMATELY DIMINISHING BY LATE IN THE AFTERNOON. HIGH
PRESSURE BUILDS IN FROM THE NORTH-NORTHWEST AND WINDS BEGIN TO TURN
MORE TOWARDS THE NORTHEAST BY THURSDAY AND FRIDAY. SEAS WILL DROP
FROM 8 FEET EARLY WEDNESDAY TO 4 FEET BY EARLY THURSDAY MORNING AND
REMAIN THERE THROUGH AT LEAST SATURDAY. THIS IS WHEN THE NEXT
SYSTEM, A COLD FRONT, MOVES IN FROM THE NORTHWEST AND COULD AFFECT
OUR WATERS WITH SHOWERS AND POSSIBLE THUNDERSTORMS. WINDS WILL
GENERALLY BE OUT OF THE SOUTH-SOUTHEAST ON SATURDAY AND THEN TURN
TOWARDS THE WEST AFTER THE FRONT GOES THROUGH BY SUNDAY.
&&
.TIDES/COASTAL FLOODING...
CBOFS, DBOFS AND A LOCAL ALGORITHM ARE POINTING TO ADVISORY LEVEL
TIDES FROM REEDY POINT UP THE TIDAL DELAWARE RIVER THIS AFTERNOON
AND UP CHESAPEAKE BAY THIS EVENING INTO THE OVERNIGHT. WITH A STRONG
SOUTHERLY FLOW EXPECTED TO DEVELOP AND WITH THE POSSIBILITY OF HEAVY
RAINFALL NOT BEING ABLE TO DRAIN WELL IF IT OCCURS AROUND HIGH TIDE,
WE ISSUED AN ADVISORY FOR THE ABOVE LOCATIONS.
&&
.RIP CURRENTS...
WE HAVE GONE WITH A HIGH RISK OF RIP CURRENTS FOR TODAY, WITH
WAVES IN THE SURF ZONE EXPECTED TO BE MAINLY IN THE 4 TO 7 FOOT
RANGE ALONG WITH A STRONG SOUTHERLY WIND.
CONDITIONS SHOULD IMPROVE DURING THE MIDDLE AND LATTER PART OF
THE WEEK.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...WIND ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR PAZ054-055-
060>062-067>071.
COASTAL FLOOD ADVISORY UNTIL 6 PM EDT THIS EVENING FOR PAZ070-
071.
NJ...WIND ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR NJZ001-007>010-
012>027.
HIGH RIP CURRENT RISK UNTIL 8 PM EDT THIS EVENING FOR NJZ014-
024>026.
COASTAL FLOOD ADVISORY UNTIL 6 PM EDT THIS EVENING FOR
NJZ016>019.
DE...WIND ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR DEZ001>004.
HIGH RIP CURRENT RISK UNTIL 8 PM EDT THIS EVENING FOR DEZ004.
COASTAL FLOOD ADVISORY UNTIL 6 PM EDT THIS EVENING FOR DEZ001.
MD...WIND ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR MDZ008-012-015-
019-020.
COASTAL FLOOD ADVISORY FROM 6 PM THIS EVENING TO 1 AM EDT
WEDNESDAY FOR MDZ008-012-015-019-020.
MARINE...GALE WARNING UNTIL 4 AM EDT WEDNESDAY FOR ANZ430-431-450>455.
&&
$$
SYNOPSIS...HEAVENER
NEAR TERM...GIGI
SHORT TERM...DELISI
LONG TERM...HEAVENER
AVIATION...ROBERTSON/HEAVENER
MARINE...DELISI/HEAVENER
TIDES/COASTAL FLOODING...DELISI
RIP CURRENTS...DELISI
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
1202 PM EDT TUE SEP 18 2012
.SYNOPSIS...
SLOW MOVING, BUT POTENT, COLD FRONT WILL SWEEP THROUGH THE REGION
LATER TONIGHT AS THE PARENT LOW PRESSURE SYSTEM MOVES TO OUR
NORTHEAST. HIGH PRESSURE WILL BUILD IN FROM THE NORTH LATER ON
WEDNESDAY THROUGH FRIDAY. ANOTHER COLD FRONT LOOKS TO PUSH THROUGH
OUR REGION LATE IN THE DAY ON SATURDAY WITH HIGH PRESSURE ONCE
AGAIN FILLING IN BEHIND IT LATER ON SUNDAY INTO MONDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LOOKING AT THE 12Z SFC ANALYSIS AND UPPER AIR PATTERN. AS MY MID
SHIFT PREDECESSOR HAS BEEN SAYING FOR DAYS WE STILL HAVE AN
UNPHASED SYSTEM APPROACHING FROM THE WEST. IT LOOKS AS THOUGH MOST
OF THE ACTION WILL BE FROM THE SOUTHERN STREAM SYSTEM WITH THE
SECOND FRONT MAYBE PROLONGING LIGHTER RAIN CHANCES DEEPER INTO THE
NIGHT.
EVEN WITHOUT THE PHASING THERE IS SFC BASED INSTABILITY AND KDIX
AND KDOX VMP ARE BOTH SHOWING 50KTS OF WIND ALRDY AT 3K. THE HI
RES WRF-NMM EAST IS SHOWING THE BEST DEPICTION OF ONOGING
CONVECTION, BOTH THE HRRR AND COSPA SEEM TOO HOT TOO EAST TOO
FAST. WE HAVE CLOUDED OVER WHICH WOULD REDUCE INSTABILITY A BIT,
BUT ITS NOT ENOUGH. SO WE WILL WAIT FOR ORGANIZATION TO ENHANCE
THE POTENTIAL FOR SEVERE WEATHER AND FOLLOWING THE WRF-NMM-E FOR
NOW AS HIEST IMPACT TIME.
THE HEAVIEST RAIN HAS FALLEN SO FAR NORTH AND WEST WHERE FFG IS
HIGH, SO UNLESS THERE IS TRAINING, SO FAR SO GOOD.
IF WE DID NOT HAVE THE TOPOGRAPHY NW, WE ARE TEMPTED TO DROP THE
ADVISORY THERE, BUT WITH THE HIER TERRAIN, WE WILL KEEP IT GOING.
HIEST CONFIDENCE OUTSIDE OF CONVECTION REMAINS EAST FOR WIND ADVY
GUSTS. NO BIG CHANGES TO TEMPS AND DEW POINTS.
AS HAS BEEN NOTED IN PREVIOUS DISCUSSIONS, TODAY LOOKS TO BE AN
ACTIVE DAY. THE MODELS STILL SUPPORT THE HEAVY RAIN CONCERN
ESPECIALLY AS ONE MOVES NORTHWEST THROUGH THE FORECAST AREA. THE
ISENTROPIC LIFT RAIN OCCURRING EARLY THIS MORNING WAS MODERATE IN
NATURE, AND THE WATER VAPOR IMAGERY ALONG WITH SURFACE AND H8 DEW
POINTS AND H7 THETA E VALUES CONFIRM THAT MOISTURE IS DEEP. WE
START WITH HIGH FFG AND FFH VALUES (THE MOST VULNERABLE PLACES ARE
FAR NORTHERN NEW JERSEY AND THE AREA IN AND NEAR URBANIZED PARTS
OF THE DELAWARE VALLEY), BUT PLACES WHERE CONVECTION (ONCE IT
DEVELOPS) HITS HARDEST LIKELY WILL SEE SOME KIND OF FLOOD ADVISORY
OR WARNING. OUR QPF FOR TODAY THROUGH TONIGHT RANGES FROM A BIT
OVER AN INCH SOUTHEAST TO ALMOST 2.5 INCHES NORTHWEST, BUT LOCALES
HARD HIT BY CONVECTION COULD SEE IN EXCESS OF 4 INCHES ANYWHERE IN
THE FORECAST AREA.
REGARDING CONVECTION, THE DYNAMICS TO SUPPORT IT DEVELOP DURING THE
COURSE OF THE DAY WITH THE ADVANCING UPPER JET, A MID LEVEL IMPULSE
THAT WAS THE ROBUST TEXAS WAVE MOVING UP FROM THE SOUTHWEST, AND
GOOD MID LEVEL Q-VECTOR CONVERGENCE. LOWER LEVEL FRONTOGENESIS
INCREASES AS THE COLD FRONT APPROACHES, AND HELICITY BECOMES VERY
ROBUST AS A STRONG LOW LEVEL JET APPROACHES. THE LIMITING FACTOR
WOULD BE INSTABILITY. THERE IS ENOUGH ALOFT FOR SOME LOW TOP
CONVECTION TO DEVELOP, AND IT WOULD REQUIRE A BREAK BETWEEN THE
ISENTROPIC LIFT RAIN AND THE CONVECTIVE RAIN FOR US TO WARM
SUFFICIENTLY TO TAP THAT INSTABILITY AT THE SURFACE AND DEVELOP
STRONG TO SEVERE STORMS. THAT IS A POSSIBILITY, AND SPC MAINTAINS
OUR AREA IN A SLIGHT RISK.
REGARDING WINDS OUTSIDE OF CONVECTION, IT ALSO IS THE CASE THAT WE
WOULD HAVE TO WARM SUFFICIENTLY AT THE SURFACE TO MIX THE STRONG
WINDS AT ABOUT H950 DOWN. THE NAM SAYS WE WILL, ALTHOUGH THE GFS
DOES NOT. THE ADVISORY LIKELY STANDS A BETTER CHANCE VERIFYING
SOUTHEAST THAN NORTHWEST (EXCEPT FOR OUR HIGHER ELEVATIONS
NORTHWEST), BECAUSE THE CHANCES OF A SIGNIFICANT BREAK IN RAIN AND
CLOUDS IS HIGHER THERE. WE ARE NOT CONFIDENT ENOUGH TO TRIM THE
ADVISORY GEOGRAPHICALLY AT THIS POINT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM WEDNESDAY/...
THE COLD FRONT AND MOST OF THE SUPPORT ALOFT MOVE THROUGH THE AREA
FROM LATE EVENING NORTHWEST TO AFTER MIDNIGHT SOUTHEAST (THE HIGHER
ONE GOES, THE MORE THE KINEMATICS AND DYNAMICS HANG BACK WITH THE
UPPER JET JUST INTO OUR WESTERN ZONES AROUND DAYBREAK). THE FRONT
SHOULD TAKE THE WINDS AND THE CONVECTION (POSSIBLY STRONG) WITH
HEAVY RAIN WITH IT, ALTHOUGH THERE MAY BE SOME REAR INFLOW RAINFALL
BEHIND THE FRONT THAT WOULD BE ENHANCED (AS THE PREVIOUS LONG TERM
FORECASTER NOTED) BY TRAILING FRONTOGENETIC FORCING AND THE UPPER
JET. SINCE WINDS ALOFT ARE STRONGEST NEAR THE COLD FRONT, WE DID NOT
CHANGE THE ADVISORY TIMING AT THIS POINT ALTHOUGH IT MAY BE MORE
DIFFICULT TO MIX WINDS DOWN OUTSIDE OF CONVECTION AFTER DUSK.
GUIDANCE AND CONTINUITY WERE RELIED ON FOR MINIMUM TEMPERATURES IN
THIS DYNAMIC PERIOD.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
5-WAVE MODEL GUIDANCE SHOWS MID-LEVEL RIDGING TO OUR EAST WITH A
LONGWAVE TROUGH TO OUR IMMEDIATE WEST WITH ANOTHER RIDGE OVER THE
WESTERN UNITED STATES. THE RIDGE TO OUR EAST WILL NOT ALLOW MUCH
WEST-EAST PROGRESSION OF THE TROUGH OVER THE MID-WEST WHICH KEEPS
OUR SENSIBLE WEATHER DRY BUT A TAD COOLER THAN NORMAL WITH AN
ONSHORE FLOW ESTABLISHING ITSELF BY THURSDAY. THE BLOCKY PATTERN
WILL ALSO KEEP THE COLD FRONT THAT MOVED THROUGH LATE TUESDAY NIGHT
CLOSER TO THE COAST WHICH COULD PLAY A FACTOR IN A BIT MORE CLOUD
COVER THAN CURRENTLY FORECASTED.
DRYING TREND WILL CONTINUE THROUGH THE EARLY PART OF WEDNESDAY AS
THE POTENT COLD FRONT PUSHES FURTHER OFFSHORE, BUT AS WAS SAID
ABOVE, GETS HUNG UP A BIT. A BRISK NORTH-NORTHWEST WIND KICKS IN AND
REALLY BEGINS TO COOL THE COLUMN. 850MB TEMPERATURES DROP TO NEAR
5-6C AND IF WE ARE ABLE TO MIX UP TO THAT LEVEL ADIABATICALLY, THAT
WOULD YIELD MAXIMUM TEMPERATURES AROUND 71F...WELL BELOW NORMAL. THE
STAT GUIDANCE SUGGESTED TEMPERATURES WOULD BE A BIT WARMER THAN THIS
WHICH SEEMS COMPLETELY PROBABLE GIVEN A MINOR DOWNSLOPING COMPONENT
TOMORROW AFTERNOON UNDER AMPLE SUNSHINE.
THE STRONGER FLOW WEAKENS AS HIGH PRESSURE TO OUR NORTHWEST SLOWLY
BUILDS IN ON THURSDAY GIVING US MORE OF AN ONSHORE WIND. OCEAN
TEMPERATURES RANGING FROM THE LOW TO MID-70S SHOULD PERMIT DAYTIME
MAXES IN THE MID TO UPPER 70S, MAINLY INTERIOR AREAS, ON BOTH
THURSDAY AND FRIDAY...PLENTY OF SUNSHINE BOTH DAYS TOO. THIS HIGH
THEN SLIDES TO OUR EAST AND SETS UP A WEAK RETURN FLOW ON SATURDAY.
ENERGY ACROSS THE UPPER MID-WEST DIVES INTO THE STUCK LONGWAVE
TROUGH TO OUR WEST AND BEGINS TO NUDGE IT TOWARDS THE EAST. THIS
MID-LEVEL WAVE THEN DROPS A COLD FRONT THROUGH OUR REGION BY LATER
ON SATURDAY INTO SUNDAY MORNING. THIS IS OUR NEXT CHANCE AT
UNSETTLED WEATHER...TIMING IS STILL IN QUESTION DUE TO HOW STRONG
THE ENERGY DIVING INTO THE BASE OF THE TROUGH ACTUALLY IS AND
THEREFORE HOW FAST IT PUSHING IT EAST. FOR THE TIME BEING MAINTAINED
CHANCE POPS ON SATURDAY AND PART OF SUNDAY AND THEN DRY OUT MONDAY
WITH HIGH PRESSURE NEARING. TEMPERATURES WILL ALSO FALL BACK BELOW
NORMAL ON SUNDAY AND MONDAY BEHIND THE SECOND COLD FRONTAL PASSAGE.
&&
.AVIATION /16Z TUESDAY THROUGH SATURDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
TODAY AND TONIGHT...FREQUENT MVFR CONDITIONS WITH OCCASIONAL IFR
CONDITIONS ARE FORECAST INTO THE EVENING FIRST IN SHOWERS AND THEN
IN THUNDERSTORMS. THEY SHOULD IMPROVE TO VFR BY A FEW HOURS BEFORE
DAYBREAK FROM NORTHWEST TO SOUTHEAST. THUNDERSTORMS COULD BE
ACCOMPANIED BY STRONG WIND GUSTS. SOUTHERLY SURFACE WINDS OUTSIDE OF
THUNDERSTORMS COULD INCREASE TO ABOVE 30 KNOTS DURING THE DAY (THAT
WAS IN THE TAFS AS OF EARLY THIS MORNING), BUT IF AND WHERE THAT
DOES NOT HAPPEN LOW LEVEL WIND SHEAR WOULD DEVELOP (THAT WAS NOT IN
THE TAFS AS OF THIS MORNING). THE IMPROVEMENT TO VFR WILL
COINCIDE WITH A SHIFT IN THE WINDS TO THE WEST. ANY THREAT OF
STRONG WINDS OR LLWS WILL END WITH THAT SHIFT.
OUTLOOK...
WEDNESDAY - FRIDAY...VFR CONDITIONS EXPECTED. GUSTY NORTHWEST WINDS
ON WEDNESDAY BEGIN TO DIMINISH BY LATE EVENING. WINDS TURN MORE
NORTH-NORTHEAST ON THURSDAY AND FRIDAY. POSSIBLE MVFR VSBYS IN THE
EARLY MORNING HOURS OUTSIDE OF THE PHL METRO AREA.
SATURDAY...STARTS OFF VFR WITH POSSIBLE MVFR CIGS AND VSBYS AS COLD
FRONT SLIDES THROUGH LATER IN THE DAY. SCATTERED SHOWERS ALSO
POSSIBLE.
&&
.MARINE...
GALES WERE STARTED AT THE PRESENT AS WE ARE STARTING TO SEE SOME
GALE FORCE GUSTS.
WE MAINTAIN THE GALE WARNING AS IT WAS. WATER TEMPERATURES NEAR 25 C
STAND A FAIR CHANCE OF TAPPING THE STRONG WINDS EXPECTED TO DEVELOP
AT AROUND 1500 FT. THE COLD FRONT WILL CROSS THE WATERS WELL AFTER
MIDNIGHT TONIGHT, AND THAT WILL END THE GALES. SEAS OF UP TO 10 OR
11 FT ARE FORECAST FOR THE OCEAN AND SEAS OF UP TO 6 FT ARE FORECAST
FOR THE BAY WHILE THE GALES OCCUR.
OUTLOOK...
NORTHWEST WINDS WILL REMAIN QUITE GUSTY ON WEDNESDAY AT AROUND 25
KNOTS, ULTIMATELY DIMINISHING BY LATE IN THE AFTERNOON. HIGH
PRESSURE BUILDS IN FROM THE NORTH-NORTHWEST AND WINDS BEGIN TO TURN
MORE TOWARDS THE NORTHEAST BY THURSDAY AND FRIDAY. SEAS WILL DROP
FROM 8 FEET EARLY WEDNESDAY TO 4 FEET BY EARLY THURSDAY MORNING AND
REMAIN THERE THROUGH AT LEAST SATURDAY. THIS IS WHEN THE NEXT
SYSTEM, A COLD FRONT, MOVES IN FROM THE NORTHWEST AND COULD AFFECT
OUR WATERS WITH SHOWERS AND POSSIBLE THUNDERSTORMS. WINDS WILL
GENERALLY BE OUT OF THE SOUTH-SOUTHEAST ON SATURDAY AND THEN TURN
TOWARDS THE WEST AFTER THE FRONT GOES THROUGH BY SUNDAY.
&&
.TIDES/COASTAL FLOODING...
CBOFS, DBOFS AND A LOCAL ALGORITHM ARE POINTING TO ADVISORY LEVEL
TIDES FROM REEDY POINT UP THE TIDAL DELAWARE RIVER THIS AFTERNOON
AND UP CHESAPEAKE BAY THIS EVENING INTO THE OVERNIGHT. WITH A STRONG
SOUTHERLY FLOW EXPECTED TO DEVELOP AND WITH THE POSSIBILITY OF HEAVY
RAINFALL NOT BEING ABLE TO DRAIN WELL IF IT OCCURS AROUND HIGH TIDE,
WE ISSUED AN ADVISORY FOR THE ABOVE LOCATIONS.
&&
.RIP CURRENTS...
WE HAVE GONE WITH A HIGH RISK OF RIP CURRENTS FOR TODAY, WITH
WAVES IN THE SURF ZONE EXPECTED TO BE MAINLY IN THE 4 TO 7 FOOT
RANGE ALONG WITH A STRONG SOUTHERLY WIND.
CONDITIONS SHOULD IMPROVE DURING THE MIDDLE AND LATTER PART OF
THE WEEK.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...WIND ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR PAZ054-055-
060>062-067>071.
COASTAL FLOOD ADVISORY UNTIL 6 PM EDT THIS EVENING FOR PAZ070-
071.
NJ...WIND ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR NJZ001-007>010-
012>027.
HIGH RIP CURRENT RISK UNTIL 8 PM EDT THIS EVENING FOR NJZ014-
024>026.
COASTAL FLOOD ADVISORY UNTIL 6 PM EDT THIS EVENING FOR
NJZ016>019.
DE...WIND ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR DEZ001>004.
HIGH RIP CURRENT RISK UNTIL 8 PM EDT THIS EVENING FOR DEZ004.
COASTAL FLOOD ADVISORY UNTIL 6 PM EDT THIS EVENING FOR DEZ001.
MD...WIND ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR MDZ008-012-015-
019-020.
COASTAL FLOOD ADVISORY FROM 6 PM THIS EVENING TO 1 AM EDT
WEDNESDAY FOR MDZ008-012-015-019-020.
MARINE...GALE WARNING UNTIL 4 AM EDT WEDNESDAY FOR ANZ430-431-450>455.
&&
$$
SYNOPSIS...HEAVENER
NEAR TERM...DELISI/GIGI
SHORT TERM...DELISI
LONG TERM...HEAVENER
AVIATION...DELISI/HEAVENER
MARINE...DELISI/HEAVENER
TIDES/COASTAL FLOODING...DELISI
RIP CURRENTS...DELISI
AREA FORECAST DISCUSSION
NWS MIAMI FL
509 PM EDT TUE SEP 18 2012
.UPDATE...LINE OF SHOWERS AND THUNDERSTORMS OVER THE GULF OF
MEXICO IS MOVING TOWARDS THE GULF COAST/NAPLES AREA. THIS LINE
WILL IMPACT THIS AREA THROUGH EARLY EVENING. THE LINE IS MOVING
STEADILY EASTWARD...AND LATEST HRRR SHOWS THIS CONVECTION TRACKING
ACROSS SOUTH FLORIDA TONIGHT, REACHING THE EAST COAST METRO AREA
AT AROUND MIDNIGHT. GIVEN THE AMPLIFIED TROUGH AND INCOMING
SHORTWAVE, THIS SEEMS PLAUSIBLE. AS SUCH, HAVE UPDATED THE
FORECAST TO ACCOUNT FOR LIKELY ACTIVITY GULF COAST AND A CHANCE
OF THUNDERSTORMS EAST COAST METRO TONIGHT...AS THERE IS THE
POTENTIAL FOR THIS LINE OF STORMS TO MOVE INTO THE AREA TONIGHT.
IN OTHER WORDS, NOT OUR TYPICAL DIURNAL CYCLE. LIGHTNING/HEAVY
RAINS MAIN IMPACTS, BUT LOCALIZED WIND GUSTS OF 40-50 MPH
POSSIBLE. /GREGORIA
&&
.PREV DISCUSSION... /ISSUED 210 PM EDT TUE SEP 18 2012/
DISCUSSION...AN EXTREMELY COMPLEX WEATHER PATTERN IS DEVELOPING
ACROSS THE U.S. WHICH WILL HAVE ITS AFFECTS ON SOUTH FLORIDA. A MID
LEVEL TROUGH OVER THE GULF COAST NEAR THE LOWER MISSISSIPPI VALLEY
THIS MORNING IS BECOMING ABSORBED INTO LARGER SCALE TROUGH DEEPENING
INTO THE SOUTHEAST STATES WITH ITS ASSOCIATED COLD FRONT MOVING INTO
THE FL PANHANDLE. THIS SYSTEM WILL RAPIDLY LIFT TO THE NORTHEAST
TONIGHT AND WEDNESDAY AS ANOTHER TROUGH ROTATES THROUGH THE BASE OF
THE MAIN TROUGH AXIS AND MASSIVE RIDGES BUILD OVER THE WESTERN U.S.
AND THE WESTERN ATLANTIC. THIS IN TURN WILL ALLOW THE COLD FRONT TO
MOVE INTO NORTH CENTRAL FLORIDA AND STALL AS THE PENINSULA SOMEWHAT
BECOMES SANDWICHED IN BETWEEN ALL OF THESE SYSTEMS. THIS EVOLVING
SITUATION WILL ALSO RESULT IN ANOTHER DAY ON WEDNESDAY OF DEEP
SOUTHWESTERLY FLOW AND KEEP THE HIGHEST POPS OVER THE INTERIOR AND
EAST COAST METRO REGIONS.
ON THURSDAY, THE RIDGE OUT WEST WILL CONTINUE TO AMPLIFY WITH THE
MAIN ENERGY OF THE EASTERN TROUGH CONTINUING TO LIFT TO THE
NORTHEAST. THIS HAPPENS DUE TO THE ATLANTIC RIDGE SHIFTING WEST AS A
LARGE MID LEVEL TROUGH MOVES INTO THE CENTRAL ATLANTIC. REACTING TO
THIS WILL BE THE SFC RIDGE SHIFTING BACK NORTH PLACING SOUTH FLORIDA
IN A LOW LEVEL SOUTHEAST FLOW WITH WEAKER STEERING ALOFT. THE END
RESULT WILL BE SEA BREEZE DRIVEN ACTIVITY MOVING VERY LITTLE BUT
TENDING TO FAVOR THE INTERIOR SECTIONS. ALL IN ALL IN THE SHORT
TERM, MAJOR WEATHER SYSTEMS WILL BE FAR REMOVED FROM SOUTH FLORIDA
BUT PLACING US IN A FAVORABLE LOCATION FOR DAILY AFTERNOON/EVENING
SHOWERS AND THUNDERSTORMS.
IN THE EXTENDED PERIOD INTO THE WEEKEND AND EARLY NEXT WEEK, THE
WEATHER PATTERN WILL CHANGE VERY SLOWLY AND IT APPEARS THAT SOUTH
FLORIDA WILL BE UNDER THE INFLUENCE OF SEVERAL DAYS WITH SEA BREEZE
INTERACTION VARIETY THUNDERSTORM ACTIVITY. SO THE MAIN AREA OF
CONCERN FOR RAINFALL FROM THURSDAY INTO EARLY NEXT WEEK WILL BE THE
FAR WESTERN SUBURBS OF BOTH COASTS AND ANY LOCATION OVER THE
INTERIOR.
AVIATION...A RIDGE OF HIGH PRESSURE AT THE SURFACE AND ALOFT
SOUTHEAST OF THE AREA AND OVER THE FLA STRAITS WILL PERSIST THROUGH
THE PERIOD. WINDS WILL BE SOUTHERLY < 10 KTS THEN BECOME SSW TO SW
AND INCREASE 10 TO 15 KNOTS AS THE DAY PROGRESSES. NO E COAST SEA
BREEZE EXPECTED. WITH THE SSW-SW WIND FLOW...SOME VCSH AT KAPF WITH
VCTS EXPECTED AT ALL TERMINALS AFT 17Z. POSSIBLE THAT SOME MVFR
VSBY/CIG AT ANY ONE TERMINAL IF A TSRA MOVES OVER LATER TODAY.
MARINE...OUTSIDE OF SHOWERS AND THUNDERSTORMS, BOATING CONDITIONS
WILL BE TRANQUIL WITH A SOUTH TO SOUTHWEST WIND LESS THAN 15 KNOTS
THROUGH WEDNESDAY BECOMING SOUTHEASTERLY AT LESS THAN 15 KNOTS
THURSDAY INTO THE WEEKEND. THIS WILL RESULT IN SEAS OF LESS THAN 4 FEET.
FIRE WEATHER...NO PROBLEMS OR CONCERNS.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 76 89 75 87 / 40 50 30 40
FORT LAUDERDALE 77 90 76 87 / 40 40 20 40
MIAMI 77 90 78 88 / 40 40 20 40
NAPLES 76 89 74 89 / 60 30 20 40
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS TAMPA BAY RUSKIN FL
200 PM EDT TUE SEP 18 2012
.SYNOPSIS...
18Z WATER VAPOR AND H4 RUC ANALYSIS SHOWS A HIGHLY AMPLIFIED UPPER
LEVEL PATTERN ACROSS NORTH AMERICA. NORTHERN STREAM FLOW ARRIVES
ATOP RIDGING ALONG THE BRITISH COLUMBIA COASTLINE BEFORE RAPIDLY
DIVING SOUTHWARD INTO A DOMINANT LONG WAVE TROUGH IN CONTROL OF THE
EASTERN HALF OF THE CONTINENT. THIS TROUGH AXIS EXTENDS FROM ONTARIO
THROUGH THE GREAT LAKES AND DOWN ALL THE WAY TO THE NORTHERN GULF
COAST. SHORTWAVE ENERGY ROUNDING THE BASE OF THIS TROUGH HAS BEEN
PIVOTING EASTWARD AND NORTHEASTWARD TODAY FROM NEAR THE MS DELTA
REGION TO SOUTHERN AL/GA. DEEP LAYER QG FORCING IN ADVANCE OF THIS
ENERGY ALONG WITH SOME WEAK UPPER LEVEL DIFFLUENCE AND ABUNDANT DEEP
LAYER MOISTURE HAS BEEN SUFFICIENT TO FORCE SEVERAL BANDS OF
CONVECTION ACROSS NORTH/CENTRAL FLORIDA AND THE EASTERN GULF OF
MEXICO. THE MOST ORGANIZED CONVECTION AND HIGHEST RAIN CHANCES
(CATEGORICAL) WILL REMAIN FROM THE TAMPA BAY AREA NORTHWARD THE REST
OF THE AFTERNOON. SOUTH OF TAMPA BAY RAIN CHANCES (SCATTERED
SHOWERS/STORMS) WILL CONTINUE TO INCREASE IN COVERAGE...BUT BE A
RESULT OF MORE TYPICAL DIURNAL HEATING PROCESSES.
AT THE SURFACE...FORECAST AREA RESIDES BETWEEN THE SUBTROPICAL RIDGE
AXIS ALONG THE FLORIDA STRAITS AND A COLD FRONT EXTENDING FROM NEAR
ATLANTA GA SOUTHWARD TO THE FLORIDA PANHANDLE. THIS FRONT WILL
SLOWLY PROCEED EASTWARD...BUT WILL NOT BE REACHING OUR ZONES THROUGH
TONIGHT.
&&
.SHORT TERM (TONIGHT THROUGH THURSDAY)...
TONIGHT...THE SHORTWAVE ENERGY THAT HAS BEEN FORCING MUCH OF THE
ORGANIZED CONVECTION TODAY WILL BE SHEARING OUT TO THE NORTHEAST
THIS EVENING WITH A WEAKENING OF THE OVERALL SYNOPTIC FORCING.
HOWEVER...WITH THE MAIN UPPER LEVEL TROUGH AXIS STILL TO OUR
WEST...THE WEAK DIFFLUENCE ALOFT...ALONG WITH ANY SMALLER IMPULSE
MOVING THROUGH THE FLOW WILL KEEP PERIODS OF SHOWERS AND STORMS
MOVING ASHORE. FORECAST WILL SHOW POPS IN THE LIKELY RANGE MOST
PLACES THROUGH THE EVENING HOURS...AND THEN TAPER BACK TO CHANCE
POPS AFTER MIDNIGHT.
WEDNESDAY...COLD FRONT WILL SETTLE OVER THE NATURE COAST ZONES IN A
POSITION FAR ENOUGH NORTH TO PREVENT ANY SIGNIFICANT INTRUSION OF
DRIER AIR. WHILE NO POTENT IMPULSES ARE EXPECTED TO ORGANIZE
CONVECTION...THE GENERAL CYCLONIC FLOW...DEEP MOISTURE AND
DIFFLUENCE ALOFT SHOULD RESULT IN DECENT COVERAGES OF SHOWERS AND
STORMS THROUGH THE DAY. THESE STORMS MAY BE MOSTLY CONFINED CLOSE TO
THE COAST IN THE MORNING...BUT SHOULD EXPAND INLAND WITH TIME AS
DIURNAL HEATING AIDS THE OVERALL LIFT. HAVE GONE WITH CHANCE 30-50%
POPS NORTH AND LIKELY 60% POPS ALONG AND SOUTH OF THE I-4 CORRIDOR.
THURSDAY...
UPPER TROUGH WILL BEGIN TO SHOW SIGNS OF WEAKENING WHILE THE SURFACE
FRONT DISSIPATES OVER THE NORTHERN/CENTRAL PENINSULA. WITH LESS IN
THE WAY OF FOCUS FOR LIFT...WILL KEEP LIKELY POPS OUT OF THE
FORECAST FOR THE TIME BEING. HOWEVER...DEEP LAYER MOISTURE WILL
STILL BE IN PLACE...AND THIS SHOULD BE ENOUGH TO SUPPORT AT LEAST OF
CHANCE POP FOR SCATTERED MAINLY DIURNALLY FORCED CONVECTION.
&&
LONG TERM (FRIDAY THROUGH MONDAY)...
LITTLE CHANGE IN THE U/L PATTERN THROUGH THE PERIOD AS AN EXTENSIVE
L/W TROUGH EXTENDING FROM THE GREAT LAKES THROUGH THE NORTHERN GULF
OF MEXICO FRIDAY WILL ONLY PUSH TO THE EASTERN SEABOARD BY MONDAY AS
STRONG U/L DISTURBANCES ROTATE THROUGH THE BASE OF THE TROUGH...WITH
THE TROUGH AMPLIFYING AND DIGGING OVER THE SOUTHEAST U.S. SUNDAY.
WEAK SURFACE HIGH ALONG THE EAST COAST FRIDAY AND SATURDAY WITH WEAK
EASTERLY GRADIENT ACROSS WEST CENTRAL AND SOUTHWEST FLORIDA. DEEP
LAYER MOISTURE WILL BE SUFFICIENT FOR SCATTERED AFTERNOON SHOWERS
AND THUNDERSTORMS TO DEVELOP WHICH WILL BE ENHANCED ALONG THE WEST
COAST SEA BREEZE BOUNDARY. HIGHEST POPS FROM TAMPA SOUTH TO FORT
MYERS IN REGION OF BEST MOISTURE AVAILABILITY AND INSTABILITY. A
COLD FRONT WILL MOVE ACROSS THE SOUTHEAST U.S. SATURDAY NIGHT INTO
SUNDAY AND STALL OVER NORTH FLORIDA. SURFACE HIGH PRESSURE BUILDING
OVER THE MIDWEST WILL ADVECT SLIGHTLY DRIER AIR OVER PORTIONS OF THE
FORECAST AREA SUNDAY AND MONDAY WITH DEW POINTS DROPPING INTO THE
MID 60S IN PORTIONS OF THE NORTHERN CWA AND INTERIOR. THE DRIER AIR
WILL ALSO SIGNIFICANTLY DECREASE THE CHANCE OF SHOWERS AND
THUNDERSTORMS BOTH SUNDAY AND MONDAY. TEMPERATURES WILL RUN NEAR
CLIMATIC NORMALS THROUGH THE PERIOD.
&&
.AVIATION...
CONTINUED MVFR/IFR WITH GUSTY WINDS IN TSRA FOR PIE AND TPA THROUGH
20Z. OTHERWISE PRIMARILY VFR.
&&
.MARINE...
A COLD FRONT WILL CONTINUE TO SLOWLY CROSS THE NORTHEAST GULF OF
MEXICO TONIGHT AND WEDNESDAY. ADVISORY AND CAUTIONARY LEVEL WINDS
ONGOING ACROSS THE NORTHERN AND CENTRAL WATERS WILL SLOWLY DECREASE
AS THE FRONT APPROACHES TONIGHT. THE FRONT WILL THEN SLOWLY DECAY
INTO THE LATER PORTION OF THE WEEK ALLOWING WINDS AND SEAS TO
FURTHER DIMINISH.
&&
.FIRE WEATHER...
A WEAK COLD FRONT WILL SLOWLY SAG INTO THE REGION FROM THE NORTHWEST
LATER TONIGHT AND WEDNESDAY...AND THEN DECAY INTO THE LATER PORTION
OF THE WEEK. THERE WILL NOT BE MUCH IN THE WAY OF DRIER AIR ARRIVING
WITH THIS FRONT...EVEN FOR THE NORTHERN NATURE COAST ZONES.
THEREFORE...DO NOT ANTICIPATE ANY CRITICAL FIRE WEATHER CONDITIONS
THROUGH THE REMAINDER OF THE WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 75 85 74 87 / 60 50 30 50
FMY 75 90 73 89 / 60 60 30 50
GIF 74 89 71 91 / 60 60 20 50
SRQ 76 85 73 87 / 60 50 30 50
BKV 72 87 67 88 / 60 50 20 50
SPG 77 84 75 86 / 60 50 30 50
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...BEACH HAZARDS STATEMENT UNTIL 10 PM EDT THIS EVENING FOR
CHARLOTTE-HILLSBOROUGH-LEE-MANATEE-PINELLAS-SARASOTA.
GULF WATERS...SMALL CRAFT ADVISORY UNTIL 10 PM EDT THIS EVENING FOR
TARPON SPRINGS TO SUWANNEE RIVER OUT 20 NM-TARPON
SPRINGS TO SUWANNEE RIVER OUT 20 TO 60 NM.
&&
$$
UPDATE...MROCZKA
AVIATION...JILLSON
PREVIOUS DISCUSSION...RUDE
AREA FORECAST DISCUSSION...UPDATED
NWS TAMPA BAY RUSKIN FL
950 AM EDT TUE SEP 18 2012
.UPDATE (REST OF TODAY)...
13Z WATER VAPOR AND H4 RUC ANALYSIS SHOWS A NOW HIGHLY AMPLIFIED
UPPER LEVEL PATTERN ACROSS NORTH AMERICA. NORTHERN STREAM FLOW
ARRIVES ATOP RIDGING ALONG THE BRITISH COLUMBIA COASTLINE BEFORE
RAPIDLY DIVING SOUTHWARD INTO A DOMINANT LONG WAVE TROUGH IN CONTROL
OF THE EASTERN HALF OF THE CONTINENT. THIS TROUGH AXIS EXTENDS FROM
ONTARIO THROUGH THE GREAT LAKES AND DOWN ALL THE WAY TO THE NORTHERN
GULF COAST. SHORTWAVE ENERGY ROUNDING THE BASE OF THIS TROUGH HAS
BEEN PIVOTING EASTWARD AND NORTHEASTWARD THIS MORNING FROM NEAR THE
MS DELTA REGION TO SOUTHERN AL/GA. DEEP LAYER QG FORCING IN ADVANCE
OF THIS ENERGY ALONG WITH SOME WEAK UPPER LEVEL DIFFLUENCE AND
ABUNDANT DEEP LAYER MOISTURE HAS BEEN SUFFICIENT TO FORCE SEVERAL
LINES OF CONVECTION ACROSS NORTH FLORIDA AND THE NE GULF OF MEXICO
THIS MORNING. THESE BANDS OF CONVECTION HAVE BEEN CONSOLIDATING OVER
THE PAST FEW HOURS AND WILL KEEP RAIN CHANCES LIKELY TO CATEGORICAL
FROM TAMPA BAY NORTHWARD ALONG THE NATURE COAST ZONES INTO AT LEAST
THE EARLY AFTERNOON. SOUTH OF TAMPA BAY RAIN CHANCES (SCATTERED
SHOWERS/STORMS) WILL SLOWLY INCREASE INTO THE AFTERNOON DUE MORE TO
TYPICAL DIURNAL HEATING PROCESSES.
AT THE SURFACE...FORECAST AREA RESIDES BETWEEN THE SUBTROPICAL RIDGE
AXIS ALONG THE FLORIDA STRAITS AND A COLD FRONT EXTENDING FROM NEAR
ATLANTA GA SOUTHWARD TO THE FLORIDA PANHANDLE. THIS FRONT WILL
SLOWLY PROCEED EASTWARD...BUT WILL NOT BE REACHING OUR ZONES THROUGH
TONIGHT.
IN THE NEXT SEVERAL HOURS...AS THE MAIN AREA OF CONVECTION CROSSES
THE NATURE COAST...A FEW STRONGER STORMS ARE NOT OUT OF THE
QUESTION. LOW LEVEL JET OF 30-40 KNOTS EXTENDS DOWN INTO
LEVY/CITRUS/SUMTER COUNTIES...AND SOME OF THIS MOMENTUM WILL LIKELY
BE TRANSPORTED TO THE SURFACE BY THE CONVECTION. WILL CONTINUE TO
MONITOR RADAR TRENDS CLOSELY...BUT CURRENTLY NOT ANTICIPATING ANY
WIDESPREAD SEVERE WEATHER POTENTIAL. AFTER THE EARLY AFTERNOON
HOURS...ALTHOUGH THE FORECAST WILL REMAIN WET...THE PASSAGE AND
WEAKENING OF THE SHORTWAVE TO OUR NORTH WILL PIVOT THE LOW LEVEL JET
EASTWARD AS WELL AND DIMINISH THE OVERALL THREAT FOR STRONGER WIND
GUSTS.
&&
.PREVIOUS DISCUSSION (TONIGHT THROUGH THURSDAY)...
THE LARGE SCALE TROUGH CONTINUES ACROSS THE EASTERN U.S. THROUGH THE
PERIOD. THE SHORT WAVE TROUGH ROTATES THROUGH THE LARGE SCALE TROUGH
TODAY AND THEN TRACKS NE AS IT DAMPENS OUT TONIGHT. THE GULF COAST
COMPLEX WILL MOVE NE ACROSS THE SE U.S. AND MERGE WITH THE PLAINS
FRONT AS THAT FEATURE SHIFTS TO THE EAST AND SE. THIS FRONT SAGS IN
ACROSS CENTRAL FL BY WED AND THEN WEAKENS THERE THROUGH THU.
WITH THE AREA UNDER DEEP AND MOIST SW FLOW THE FORECAST WILL
CONTINUE WITH SHOWERS AND THUNDERSTORMS. THESE WILL BE SCATTERED TO
NUMEROUS TODAY WITH THE HIGHEST COVERAGE IN THE NORTH AS UPPER LEVEL
ENERGY MOVES BY TO THE NORTH. THIS MAY ALSO RESULT IN SOME OF THE
STORMS BECOMING STRONG. SHOWERS AND STORMS WILL TAPER OFF WED AND
THU...BUT STILL STAY IN THE SCATTERED RANGE...AS THE FRONT BEGINS TO
DECAY AND SLIGHTLY DRIER AIR WORKS IN FROM THE NW. HIGH TEMPERATURES
WILL RUN NEAR NORMAL ALTHOUGH THEY MAY WARM A DEGREE OR TWO BY
THU...THE LOWS WILL BE JUST ABOVE NORMAL. ROBUST SOUTHWEST WINDS
TODAY RESULT IN THE THREAT OF RIPS CURRENTS AT AREA BEACHES AND A
BEACH HAZARD STATEMENT WILL IN IN PLACE THROUGH THIS EVENING. AFTER
TODAY WINDS CONTINUE SW OR WEST AND GRADUALLY DIMINISH.
&&
.AVIATION...
VFR WITH TEMPO MVFR/IFR AS SHOWERS MOVE IN OFF THE GULF THIS
MORNING. MAIN IMPACTS WILL BE BEFORE 14Z AT PIE...TPA AND SRQ. VFR
WITH VCTS AFTER 14Z.
&&
.MARINE...
WINDS WILL BE AT ADVISORY LEVELS IN THE NORTH AND CAUTION CRITERIA
ACROSS THE CENTRAL TODAY. THE NEXT FORECAST WILL HEADLINE THOSE
AREAS. AS THE FRONT SAGS IN ACROSS THE WATERS BY WED AND BEGINS TO
DECAY THE GRADIENT WILL RELAX WITH DIMINISHING WINDS AND SEAS.
ALTHOUGH SHOWERS AND THUNDERSTORMS ARE EXPECTED THROUGH THE PERIOD.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 89 75 86 75 / 60 30 50 30
FMY 90 75 89 74 / 50 30 50 20
GIF 89 73 90 74 / 60 30 50 20
SRQ 90 76 86 77 / 60 30 50 30
BKV 89 72 88 70 / 60 30 40 20
SPG 89 77 86 78 / 60 30 50 30
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...BEACH HAZARDS STATEMENT FROM 10 AM EDT THIS MORNING
THROUGH THIS EVENING FOR CHARLOTTE-HILLSBOROUGH-LEE-
MANATEE-PINELLAS-SARASOTA.
GULF WATERS...SMALL CRAFT ADVISORY UNTIL 10 PM EDT THIS EVENING FOR
TARPON SPRINGS TO SUWANNEE RIVER OUT 20 NM-TARPON
SPRINGS TO SUWANNEE RIVER OUT 20 TO 60 NM.
&&
$$
UPDATE...MROCZKA
AVIATION...JILLSON
PREVIOUS DISCUSSION...RUDE
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
714 PM CDT WED SEP 19 2012
.UPDATE...
HAVE SENT AN UPDATE TO FRESHEN UP PRECIPITATION AND WIND TRENDS.
REMOVED POPS FROM SOUTH OF INTERSTATE 80 THIS EVENING AS THERE
HAS BEEN NO NEW DEVELOPMENT ON EITHER SATELLITE OR RADAR IN THAT
DIRECTION. THERE ARE A FEW STORMS IN SOUTH CENTRAL IOWA...BUT
THESE CELLS APPEAR MORE DIURNALLY BASED AND SHOULD DISSIPATE IN
THE NEXT COUPLE HOURS. HOWEVER...THIS IS A VERY POWERFUL FRONT
AND WILL MONITOR AND MAKE ADJUSTEMENTS AS NEEDED. LE
&&
.AVIATION...
COLD FRONT MOVING THROUGH THE AREA AT THIS TIME PRODUCING SHOWERS
AND AN ISOLATED THUNDERSTORM. THE ONE STORM TO AFFECT KDBQ UNTIL
NO LATER THAN 01Z...THEN THEY WILL BE DONE. KCID AND KMLI HAVE
VCSH FOR AN HOUR OR TWO AHEAD OF THE COLD FRONT PASSAGE. WIND
SWITCH WITH COLD FRONT PASSAGE HAS BEEN ABRUPT AND WINDS HAVE BEEN
STRONG ON BOTH SIDES OF BOUNDARY. WITH SUNSET THESE WINDS SHOULD
DIMINISH AND EXPECT THAT BY FROPA AT KMLI AND KBRL POST FRONT WINDS
TO BE NORTHWEST AT LESS THAN 10KTS. WINDS TO DIMINISH OVERNIGHT AS
HIGH PRESSURE BEGINS TO BUILD IN. GRADIENT STILL IN AREA THURSDAY
TO ALLOW WINDS TO INCREASE TO 10-15KT RANGE LATE MORNING. LE
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
.PREV DISCUSSION... /ISSUED 306 PM CDT WED SEP 19 2012/
SYNOPSIS...
12Z UA ANALYSIS HAD A STRONG UPPER LOW EAST OF LAKE WINNIPEG. THE
850MB COLD FRONT RAN FROM THE ARROW HEAD OF MINNESOTA TO EASTERN
WYOMING. THE 850MB WARM FRONT RAN SOUTH ROUGHLY ALONG THE
MISSISSIPPI RIVER. STRONG CAA WAS OCCURRING BEHIND THE UPPER FRONT
WITH 850MB TEMPERATURES QUICKLY DROPPING INTO THE SINGLE DIGITS AT
THE INTERNATIONAL BORDER. SATELLITE TRENDS THROUGH MID AFTERNOON
SHOW RAPID DEVELOPMENT OF CLOUDS ALONG THE SFC COLD FRONT FROM
SOUTHEAST MINNESOTA INTO NORTHWEST IOWA. RADARS WERE SHOWING VIRGA
DEVELOPING FROM NORTHEAST IOWA INTO WESTERN WISCONSIN.
18Z SFC ANALYSIS HAD THE COLD FRONT RUNNING FROM THE KDLH AREA TO
SOUTHEAST COLORADO. A NARROW TONGUE OF LOW AND MID 50 DEW POINTS RAN
FROM THE SOUTHERN PLAINS INTO WESTERN IOWA. DEW POINTS IN THE 40S
WERE COMMON ACROSS MUCH OF THE MIDWEST AND WESTERN GREAT LAKES. DEW
POINTS IN THE 30S WERE ACROSS THE NORTHERN PLAINS AND GREAT LAKES.
SHORT TERM...TONIGHT AND THURSDAY...
BASED ON RADAR TRENDS...VIRGA IS BECOMING MORE PRONOUNCED FROM THE
CU FIELD THAT IS DEVELOPING ALONG THE COLD FRONT AND PRE-FRONTAL
TROF. RAP TRENDS CONTINUE TO SHOW MID LEVEL FORCING WILL INCREASE
THROUGH THE REMAINDER OF THE AFTERNOON WITH IT MAXIMIZING RIGHT
AROUND 00Z. FCST SOUNDINGS INDICATE CLOUD BASES IN THE 7-10 KFT AGL
RANGE SO THE VIRGA SHOULD BE QUITE OBVIOUS LATE THIS AFTERNOON IN
THE NORTHWEST PART OF THE CWFA WITH IT POTENTIALLY COMING FROM RADAR
RETURNS OF 30 DBZ OR HIGHER. EVENTUALLY...PRECIP WILL REACH THE
GROUND SO THE SCHC/CHC FOR LATE THIS AFTERNOON STILL LOOKS OKAY.
THE FRONT WILL SWEEP ACROSS THE CWFA DURING THE EVENING HOURS. AS
THE FORCING REACHES A MAXIMUM EARLY THIS EVENING THE POTENTIAL FOR A
COUPLE OF TSRA RIGHT ALONG THE FRONT IS POSSIBLE. HOWEVER...THE
NUMBER OF TSRA SHOULD BE NO MORE THAN A HANDFUL. THERE SHOULD STILL
BE CONSIDERABLE VIRGA INTO THE EARLY EVENING WITH THE MEASURABLE
RAIN LIKELY CONFINED TO A NARROW BAND ALONG THE FRONT.
BY MID EVENING THE RAIN SHOULD BE EAST OF THE MISSISSIPPI AND EXIT
THE AREA BY MIDNIGHT. STRONG SUBSIDENCE BEHIND THE SHORTWAVE SHOULD
RESULT IN SKIES CLEARING FAIRLY QUICKLY. AS THE HIGH BUILDS IN WINDS
SHOULD BECOME LIGHT WHICH WILL ALLOW TEMPERATURES TO DROP AS THE
SKIES CLEAR. THE WAPSI VALLEY ALONG WITH FAVORED COLD AREAS IN THE
NORTHERN CWFA SHOULD SEE THE COOLEST TEMPERATURES BY SUNRISE
THURSDAY.
ON THURSDAY QUIET AND DRY CONDITIONS WITH COOLER TEMPERATURES WILL
BE SEEN AS HIGH PRESSURE QUICKLY MOVES ACROSS THE AREA. ..08..
LONG TERM...THURSDAY NIGHT THROUGH NEXT WEDNESDAY...
THE EXTENDED FORECAST REMAINS VERY ACTIVE WITH MANY PASSING STRONG
SHORT WAVES ROUNDING THE BASE OF A STRONG UPPER AIR TROF IN THE
GREAT LAKES. THIS RESULTS IN SEVERAL DAYS OF FORECAST RAIN
CHANCES...WHICH ARE ALL LOW IN CONFIDENCE DUE TO THE CHANGEABLE
FORCING FORECAST FROM RUN TO RUN...AND MODEL TO MODEL. MUCH HIGHER
CONFIDENCE IS THAT WE WILL SEE A VERY COOL PERIOD OF DAYS...FOLLOWED
BY MODERATE WARMING. BY THURSDAY NIGHT THE PATTERN WILL ALREADY BE
ESTABLISHED...WITH THE 1ST OF SEVERAL WAVES ALREADY APPROACHING.
THIS SHOULD GENERATE WARM ADVECTION THEN STRONGLY FORCED COLD
FRONTAL SHOWERS FROM LATE THURSDAY NIGHT THROUGH FRIDAY MORNING.
RAINFALL AMOUNTS SHOULD BE LIGHT...BUT COULD BE UP TO 0.25 IN
SPOTS...ESPECIALLY NORTHEAST. FRIDAY LOOKS TO BE BLUSTERY UNDER
THE CLOUD COVER...THEN AFTER SEVERAL HOURS OF EASING EVENING
WINDS...AND CLEAR SKIES...WE WILL SEE A VERY STRONG UPPER WAVE DROP
SOUTH. THIS FRONT WILL SWEEP THROUGH EARLY SATURDAY...RESULTING IN
GUSTY NORTH WINDS...AND VERY STRONG COLD ADVECTION. SATURDAYS
TEMPERATURES FORECAST WITH HIGHS IN THE MID 50S NORTH TO LOWER 60S
SOUTH SEEMS OPTIMISTIC DESPITE IT BEING LOWER THAN MOST GUIDANCE.
SHOULD RAIN LINGER INTO THE DAY FOR MORE THAN A FEW HOURS...WE COULD
SEE HIGHS IN THE 40S...WITH PLENTY OF WIND. SHOULD SUNSHINE BECOME
WIDESPREAD SATURDAY AFTERNOON...RESULTING IN DEEPER MIXING...A WIND
ADVISORY IS NOT OUT OF THE QUESTION.
SATURDAY NIGHT...AND SUNDAY NIGHT...A FROST OR FREEZE IS POSSIBLE.
THIS PAST MORNING...WITH ONLY 1/2 OF A NIGHT SEEING CLEAR SKIES...WE
HIT THE MID 30S WITH 850MB TEMPERATURES OF 3 DEGREE. BOTH UPCOMING
NIGHTS THIS WEEKEND SHOULD SEE 850MB TEMPS OF +1 TO -2 DEGREES.
WHILE WINDS MAY NOT BE AS LIGHT...THIS SHOULD STILL RESULT IN COOLER
NIGHTS THAN LAST NIGHT. FOR NOW...UNTIL WE ARE CERTAIN...WILL KEEP
LOWS OF MID 30S FORECAST. SUNDAY ITSELF SHOULD BE A PLEASANT BUT
COOL DAY IN THE UPPER 50S TO LOWER 60S...AS WIND SHOULD BE LESS OF
AN ISSUE.
MONDAY INTO TUESDAY...MODERATING TEMPERATURES AND A DEVELOPING
SOUTHERLY FLOW SHOULD ALLOW FOR TEMPERATURES TO RETURN TO THE UPPER
60S MONDAY...AND MID 70S TUESDAY. TUESDAY INTO WEDNESDAY...MOISTURE
ADVECTION OVER A DEVELOPING WARM FRONT NEARBY SHOULD ALLOW FOR RAIN
POSSIBILITIES...AND POSSIBLE CONVECTION.
ERVIN
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1126 AM MDT TUE SEP 18 2012
.UPDATE...
ISSUED AT 1058 AM MDT TUE SEP 18 2012
LATEST SURFACE ANALYSIS SHOWS A SURFACE TROUGH JUST EAST OF AN
IMPERIAL TO GOODLAND LINE...EXTENDING SOUTH BETWEEN LAMAR AND
TRIBUNE. UPSTREAM WINDS IN THE NEBRASKA PANHANDLE REPORT WIND
GUSTS OF 25 MPH...WITH GUSTS NEAR 20 MPH OVER EASTERN COLORADO.
AM THINKING THE STRONGER WIND GUSTS OVER 25 MPH SHOULD REMAIN
NORTH OF THE AREA.
IN ADDITION LATEST HRRR MODEL RUNS/MOS AGREE WITH PLACING THE
CORRIDOR OF STRONGEST WINDS FROM ROUGHLY YUMA SOUTHEAST TO
ST.FRANCIS FOR THE AFTERNOON. THE HRRR HAS REDUCED THE WIND GUSTS
FOR THE AFTERNOON SO AM MORE CONFIDENT THAT A FIRE WEATHER
HIGHLIGHT WILL NOT BE NEEDED. HOWEVER CONDITIONS OVER THE
OUTLINED AREA MAY REACH CRITICAL FIRE WEATHER CONDITIONS FOR AN
HOUR OR TWO DURING THE MID AFTERNOON...WHICH IS TOO BRIEF A WINDOW
FOR A HIGHLITE TO BE ISSUED.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 200 AM MDT TUE SEP 18 2012
SFC HIGH JUST EAST OF THE AREA WILL CONTINUE TO MOVE AWAY FROM THE
AREA AS A SFC TROUGH MOVES IN. BREEZY NORTHWEST WINDS TO 25 MPH
EXPECTED WITH THIS TROUGH AS WELL AS SOME MID AND HIGH LEVEL
CLOUDS. HIGH TEMPERATURES TODAY REBOUND BACK INTO THE MID 70S TO
AROUND 80 IN EASTERN COLORADO...LOW TO MID 80S ELSEWHERE. LOWS
TONIGHT IN THE 40S TO AROUND 50.
COLD FRONT MOVES THROUGH WEDNESDAY...HOWEVER ITS IMPACT REGARDING
TEMPERATURE WONT BE FELT TIL THURSDAY. WEDNESDAY HIGHS 75 TO 80 IN
EASTERN COLORADO...MID 80S TO AROUND 90 ELSEWHERE WITH GUSTY NORTH
WINDS TO 25 OR 30 MPH. FOR WEDNESDAY NIGHT LOWS IN THE UPPER 30S TO
UPPER 40S.
SLIGHTLY COOLER TEMPERATURES IN THE LOW TO MID 80S EXPECTED THURSDAY
UNDER SOME MID AND UPPER LEVEL CLOUDS. LOWS THURSDAY NIGHT IN THE
UPPER 40S TO MID 50S.
.LONG TERM...(FRIDAY THROUGH MONDAY)
ISSUED AT 200 AM MDT TUE SEP 18 2012
AN UPPER-LEVEL RIDGE WILL DEVELOP OVER THE GREAT BASIN REGION AND
MOVE EASTWARD OVER THE ROCKIES DURING THE EXTENDED PERIOD.
MEANWHILE SURFACE HIGH PRESSURE WILL BUILD IN OVER THE NORTHERN
PLAINS AS A STRONG TROUGH OVER THE MIDWEST AT THE BEGINNING OF THE
PERIOD MOVES EAST. OVERALL THE FLOW FOR THE TRI-STATE REGION WILL
BE OUT OF THE NORTHWEST DUE TO THIS PATTERN. WITH NO SIGNIFICANT
FORCING NOR MOISTURE SOURCE AVAILABLE...NO PRECIPITATION IS
EXPECTED THRU MONDAY. ADJUSTED TEMPERATURES DOWN SLIGHTLY EARLY IN
THE WEEKEND TO BETTER MATCH BIAS CORRECTED GUIDANCE AND MODEL
TREND OVER THE PAST FEW DAYS. THE PERIOD WILL BEGIN COOLER THAN
NORMAL AND BECOME WARMER THAN NORMAL BY MONDAY AS THE RIDGE MOVES
OVER THE HIGH PLAINS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1058 AM MDT TUE SEP 18 2012
VFR CONDITIONS FORECAST FOR THE 18Z TAFS. LATEST SURFACE ANALYSIS
PLACES A TROUGH JUST EAST OF KGLD. AM EXPECTING THE TROUGH TO MOVE
THROUGH KMCK AROUND 20Z...OR POSSIBLY AN HOUR SOONER. WINDS MAYBE
GUSTY BEHIND THE TROUGH...BUT THE MAIN AREA OF GUSTS IS WELL
BEHIND THE TROUGH OVER THE SOUTHERN NEBRASKA PANHANDLE. THE WINDS
WILL DECLINE DURING THE LATE AFTERNOON...BECOMING VARIABLE
OVERNIGHT.
WEDNESDAY ANOTHER SURFACE TROUGH/COLD FRONT WILL MOVE THROUGH
DURING THE MORNING/EARLY AFTERNOON...WITH WINDS INCREASING BEHIND
THE TROUGH/FRONT DURING THE LATE MORNING AND AFTERNOON.
&&
.FIRE WEATHER...
ISSUED AT 200 AM MDT TUE SEP 18 2012
CRITICAL FIRE WEATHER CONDITIONS ARE POSSIBLE WEDNESDAY AFTERNOON
BEHIND A COLD FRONTAL PASSAGE. RELATIVE HUMIDITY VALUES AS LOW AS
15 PERCENT AND NORTH WINDS GUSTING TO 25 MPH ARE EXPECTED. A FIRE
WEATHER HIGHLITE MAY BE NEEDED FOR LOCATIONS GENERALLY ALONG AND
EAST OF THE COLORADO/KANSAS BORDER.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...JTL
SHORT TERM...99
LONG TERM...JJM
AVIATION...JTL
FIRE WEATHER...99
AREA FORECAST DISCUSSION
NWS GRAY ME
355 AM EDT TUE SEP 18 2012
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO MOVE EAST INTO THE ATLANTIC TODAY.
MEANWHILE LOW PRESSURE WILL TRACK NORTHWARD THROUGH UPSTATE NEW
YORK TODAY WITH A STRONG COLD FRONT PUSHING ACROSS NEW HAMPSHIRE
AND MAINE TONIGHT. HEAVY RAIN AND GUSTY WINDS ARE EXPECTED AS IT
MOVES THROUGH. HIGH PRESSURE WILL BUILD IN WEDNESDAY THROUGH
FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AFTER SOME FILTERED SUNSHINE EARLY THIS MORNING...WINDS WILL GRADUALLY
INCREASE TODAY WELL AHEAD OF FAST MOVING SYSTEM THAT HAS EXITED
THE GULF OF MEXICO DURING THE OVERNIGHT HOURS. MOST OF THE
RAINFALL WILL BE CONFINED TO NH...WITH POPS INCREASING LATER IN
THE DAY. THE LATEST HRRR MODEL RUN DOES HAVE SHOWER ACTIVITY
REACHING WRN ME SHORTLY AFTER 18Z.
USED A BLEND OF MAV/MET MOS FOR DAYTIME MAXES.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
VERY LITTLE IN THE WAY TO THE FCST PHILOSOPHY FOR TONIGHTS FCST.
THE 00Z MODEL SUITE CONTINUES TO DEPICT LOW PRESSURE DEEPENING
THIS AFTERNOON AND EVENING...AND PASSING WELL WEST OF OUR REGION.
A STRONG SOUTHERLY GRADIENT WILL CROSS THE REGION AHEAD OF THIS
SYSTEM WITH WINDS 50-60 KT AT 925 MB. PREFFERRED THE STRONG GFS
WIND FIELDS FOR THIS RUN. THIS MODEL ALLOWS FOR THE MIXING OF WIND
GUSTS LOCALLY OVER 45 MPH ALONG THE SHORELINE AND ACROSS THE SOUTH
FACING HILLTOPS. WITH LEAVES STILL ON THE TREES...THIS WILL ALLOW
FOR DOWNED TREE LIMBS AND SOME POWER OUTAGES.
QPF IS EXPECTED TO BE IN THE 1 TO 3 INCH RAIN...WHICH OUR RIVERS
SHOULD BE ABLE TO EASILY HANDLE. DRY ANTECEDENT CONDS HAVE BEEN IN
PLACE OVER THE REGION. THE HIGHEST RAINFALL TOTALS WILL BE IN
UPSLOPE LOCATIONS OVER THE MTNS IN NRN NH. HAVE KEPT THE SLGT CHC
FOR A TSTM TO CROSS THE REGION OVERNIGHT AS WELL.
WINDS WILL DIMINISH TOWARDS MORNING FROM WEST TO EAST AS THE FRONT
CROSSES THE REGION. SLIGHTLY DRIER AIR WILL ENTER THE REGION DURG
THE DAY WEDNESDAY.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
HIGH PRES WILL BE CENTERED OVER NORTHERN NEW ENGLAND WEDNESDAY
NIGHT THROUGH THURSDAY AND THEN WILL BEGIN MOVING NORTHEAST INTO
THE MARITIMES ON FRIDAY. THIS WILL ALLOW VERY COOL TEMPERATURES
WEDNESDAY AND THURSDAY NIGHTS DUE TO RADIATIONAL COOLING WITH THE
CLEAR SKIES AND CALM WINDS. TEMPERATURES WILL DROP INTO THE UPPER 20S
AND LOWER 30S ACROSS THE MOUNTAINS AND FOOTHILLS...WHERE SOME
SITES WILL DROP BELOW FREEZING FOR THE SECOND TIME AFTER LAST
NIGHT. FOR SOME AREAS THIS WILL BE THE FIRST FREEZE. AREAS OF
FROST AND FOG ARE LIKELY ACROSS THE FOOTHILLS AS WELL. MOST OTHER
INLAND AREAS WILL DROP INTO THE MID TO UPPER 30S. A COOL SUNNY DAY
WILL BE EXPECTED THURSDAY WITH MORE CLOUDS AND MAYBE EVEN A FEW
SHWRS PSBL FRIDAY AS WE REMAIN WEDGED BETWEEN THE OFFSHORE SYSTEM
AND THE ONE DEVELOPING TO OUR W. ON SATURDAY A TROF WITH AN
ASSOCIATED COLD FRONT APPROACHES THE REGION AND MOVES THROUGH THE
REGION BY LATE SUNDAY WITH SCT SHWRS. DRY CONDITIONS AND HIGH
PRESSURE RETURN FOR THE EARLY PART OF NEXT WEEK.
&&
.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
SHORT TERM...VFR THIS MORNING...EXCEPT FOR FOG IN THE CONNECTICUT
RIVER VALLEY AT LEBANON AND WHITEFIELD TONIGHT. EXPECT
DETERIORATING CONDITIONS BEGINNING LATE THIS MORNING OVER NEW
HAMPSHIRE WITH CONDITIONS BECOMING MVFR THROUGH THE DAY IN
SHOWERS. IFR AND LIFR CONDS EXPECTED TONIGHT...BEFORE A GRADUAL
IMPROVEMENT IN CIGS/VSBYS FROM WEST TO EAST WED MRNG.
LONG TERM...PREVAILING VFR CONDITIONS THRU EARLY FRI WITH CONDS
BECOMING MVFR IN ANY SCT SHWRS OVER THE WEEKEND.
&&
.MARINE...
SHORT TERM...A STRONG SOUTHERLY FLOW WILL DEVELOP AHEAD OF A COLD
FRONT TONIGHT. A LOW LEVEL JET JUST ABOVE THE SURFACE WILL ALLOW
FOR STRONG WIND GUSTS OVER THE WATERS OVERNIGHT AND EARLY WEDNESDAY MORNING.
A GALE WARNING HAS BEEN ISSUED FOR WINDS UP TO 45 KT.
LONG TERM...WINDS AND WAVES WILL DIMINISH QUICKLY BY WEDNESDAY
NIGHT BUT WILL REQUIRE A SMALL CRAFT ADVISORY FOR A FEW HOURS ONCE
THE ABOVE WARNINGS HAVE EXPIRED. WINDS AND SEAS WILL REMAIN BLO
SCA CRIT FOR THURS AND INTO THE WEEKEND.
&&
.SPLASH-OVER AND SOME BEACH EROSION...MAY NEED TO ISSUE A
STATEMENT FOR LCL SPLASH-OVER AND BEACH EROSION FOR THE TIME OF
HIGH TIDE TONIGHT. ESTOFS EXPERIMENTAL RUNS CONT TO SHOW A 2+ FOOT
STORM SURGE OVER MUCH OF THE PENOBSCOT BAY REGION. THE HIGH
ASTRONOMICAL TIDES...STORM SURGE AND BUILDING SEAS MAY LEAD TO THE
SPLASH-OVER SHORTLY AFTER MIDNIGHT TONIGHT.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...WIND ADVISORY FROM 6 PM THIS EVENING TO 6 AM EDT WEDNESDAY FOR
MEZ007>009-012>014-018>028.
NH...WIND ADVISORY FROM 6 PM THIS EVENING TO 6 AM EDT WEDNESDAY FOR
NHZ001>010-013-014.
MARINE...GALE WARNING FROM 6 PM THIS EVENING TO 9 AM EDT WEDNESDAY FOR
ANZ150>154.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
505 PM EDT TUE SEP 18 2012
.SYNOPSIS...
SHOWERS WILL END BY THIS EVENING AS A COLD FRONT CROSSES THE
REGION. HIGH PRESSURE WILL THEN MAINTAIN DRY WEATHER UNTIL THE
APPROACH OF ANOTHER FRONT THIS WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
THE COLD FRONT NOW EXTENDS FROM JUST EAST OF DUBOIS TO ROUGHLY
MORGANTOWN AS OF 5 PM...AND CONTINUES TO TRUCK EASTWARD. WITH THE
FRONTAL PASSAGE...GOOD MIXING IS BRINGING DOWN SOME HIGHER
MOMENTUM AIR FROM THE LOWEST FEW KILOMETERS OF THE ATMOSPHERE TO
THE SURFACE. BUFKIT SOUNDINGS SUGGEST UP TO 30 KTS ARE AVAILABLE
BEHIND THE FRONT...AND SURFACE OBSERVATIONS HAVE GENERALLY
REFLECTED 20-30 KT GUSTS FAIRLY UNIFORMLY ACROSS UPSTREAM METARS
TO BELIEVE THIS SHOULD CONTINUE TO BE THE CASE AS THE FRONT
CRUISES EASTWARD OUT OF THE CWA THIS EVENING.
WHILE POPS WERE TAPERED DOWN WITH THE FRONTAL PASSAGE...THEY WERE
NOT REMOVED ALTOGETHER OVERNIGHT. LOW LEVEL LAPSE RATES AND
RESIDUAL MOISTURE IN THE LOWEST 8-10 KM COUPLED WITH NORTHWESTERLY
SURFACE FLOW WOULD INDICATE A FEW ISOLATED SHOWERS MAY BE
POSSIBLE. EVEN WITH SOME LARGE SCALE SUBSIDENCE TOWARD THE MORNING
HOURS STARTING TO ERODE THE MOIST LAYER FROM THE SOUTHWEST...POPS
WILL TAKE A WHILE TO BE REMOVED FARTHER NORTHEAST ALONG THE I-80
CORRIDOR. REGARDLESS...ALL MEANINGFUL QPF WILL BE EXHAUSTED AS THE
FRONT EXITS THIS EVENING...WITH ONLY TRIVIAL AMOUNTS BEHIND THE
FRONT. FRIES
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
THE PROGNOSIS OF A BUILDING SFC HIGH UNDER A BROAD TROF ALOFT
SUPPORTS A DRY...BUT COOL FORECAST FOR WEDNESDAY. A STRONG SHRTWV
THAT IS FORECAST TO DIG ACRS THE WRN LAKES WL AMPLIFY THE PARENT
TROF...BUT INITIATE A PD OF WARM ADVCTN THAT WL WARM THURSDAY AND
FRIDAY TEMPS BACK TOWARD NORMAL.
HOWEVER...THE NEXT IN SERIES OF REINFORCING DISTURBANCES IS
PROJECTED TO SEND A CDFNT TWD THE UPR OHIO ON FRIDAY. SLIGHT RAIN
CHANCES WERE CONTINUED FOR THE NWRN TIER OF COUNTIES FOR THE LATE
AFTN...BUT A BTR CHC OF PCPN CURRENTLY IS TIMED FOR AFTER
DARK...AND INTO SATURDAY.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
CONSENSUS OF RECENT NAEFS AND ECMWF ENSEMBLE MODEL OUTPUT SHOW A
COLD FRONT OF MODERATE STRENGTH MOVING EASTWARD THROUGH THE UPPER
OHIO VALLEY DAYTIME SATURDAY...FOLLOWED BY A COLD UPPER LEVEL
TROUGH. CONCUR WITH HPC THINKING THAT THIS SCENARIO SHOULD LIKELY
PROVIDE A FRONTAL BAND OF SHOWERS SATURDAY...AND LINGERING
SCATTERED COLD POOL INSTABILITY SHOWERS SUNDAY.
TEMPERATURES CAN BE AS MUCH AS 5 TO 10 DEGREES COOLER THAN NORMAL
FOR THIS FIRST WEEKEND OF AUTUMN.
ENSUING HIGH PRESSURE WILL PROVIDE DRY CONDITIONS MONDAY AND TUESDAY
BUT TEMPERATURES SHOULD REMAIN COOLER THAN NORMAL.
&&
.AVIATION /21Z TUESDAY THROUGH SUNDAY/...
RECENT RADAR AND SURFACE DATA...COUPLED WITH RECENT HRRR AND NAM
MODEL OUTPUT SHOWS A COLD FRONTAL BAND OF MAINLY MVFR SHOWERS WILL
PASS EASTWARD THROUGH THE UPPER OHIO VALLEY THROUGH 22Z.
SURFACE WINDS WILL BECOME WEST TO NORTHWEST WITH THE COLD FRONTAL
PASSAGE WITH GUSTS UP TO 25 KTS POSSIBLE.
CONCUR WITH NAM MODEL PROFILES AND GFS LAMP THAT POST SYSTEM COLD
POOL STRATOCUMULUS CEILINGS WILL BE MAINLY AT VFR LEVELS TONIGHT AND
DAYTIME WEDNESDAY.
SURFACE WINDS TONIGHT AND WEDNESDAY WILL BE MAINLY NORTHWEST AT NO
MORE THAN 12 KTS.
.OUTLOOK /WEDNESDAY NIGHT THROUGH SUNDAY/...
EXPECT PREVALENT VFR DUE TO HIGH PRESSURE SUBSIDENCE AND DRYING INTO
FRIDAY...ALTHOUGH A BRIEF PERIOD OF RESTRICTIONS DUE TO EARLY
MORNING FOG CANNOT BE RULED OUT. RESTRICTIONS WILL BECOME COMMON
FRIDAY NIGHT INTO SUNDAY DUE TO SHOWERS ASSOCIATED WITH THE PASSAGE
OF A COLD FRONT SATURDAY AND ENSUING COLD POOL INSTABILITY SUNDAY.
ANY REMAINING MVFR POST SYSTEM COLD POOL STRATOCUMULUS SHOULD LIFT
TO VFR LEVELS BY LATE WEDNESDAY MORNING. THEREAFTER...HIGH PRESSURE
WILL SUSTAIN DRY VFR INTO FRIDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
245 PM EDT TUE SEP 18 2012
.SYNOPSIS...
SHOWERS WILL END BY THIS EVENING AS A COLD FRONT CROSSES THE
REGION. HIGH PRESSURE WILL THEN MAINTAIN DRY WEATHER UNTIL THE
APPROACH OF ANOTHER FRONT THIS WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
MID AFTN UPDATE INCLUDED ADJUSTMENTS DUE TO RADAR AND HRRR MODEL
DEPICTIONS OF A COLD FRONTAL BAND OF SHOWERS PASSING EASTWARD
THROUGH THE UPPER OHIO VALLEY. CONTINUE TO EXPECT SHOWERS TO EXIT
EAST BY EVENING.
WITH THE ADVENT OF SUBSIDENCE AND COLD ADVCTN TNGT...EXPECT
DIMINISHED...BUT NOT ELIMINATED CLOUD COVER TO ACCOMPANY OVRNGT
LOWS APPROX 5 TO 10 DEGREES UNDER THE SEASONAL AVERAGES.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
THE PROGNOSIS OF A BUILDING SFC HIGH UNDER A BROAD TROF ALOFT
SUPPORTS A DRY...BUT COOL FORECAST FOR WEDNESDAY. A STRONG SHRTWV
THAT IS FORECAST TO DIG ACRS THE WRN LAKES WL AMPLIFY THE PARENT
TROF...BUT INITIATE A PD OF WARM ADVCTN THAT WL WARM THURSDAY AND
FRIDAY TEMPS BACK TOWARD NORMAL.
HOWEVER...THE NEXT IN SERIES OF REINFORCING DISTURBANCES IS
PROJECTED TO SEND A CDFNT TWD THE UPR OHIO ON FRIDAY. SLIGHT RAIN
CHANCES WERE CONTINUED FOR THE NWRN TIER OF COUNTIES FOR THE LATE
AFTN...BUT A BTR CHC OF PCPN CURRENTLY IS TIMED FOR AFTER
DARK...AND INTO SATURDAY.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
CONSENSUS OF RECENT NAEFS AND ECMWF ENSEMBLE MODEL OUTPUT SHOW A
COLD FRONT OF MODERATE STRENGTH MOVING EASTWARD THROUGH THE UPPER
OHIO VALLEY DAYTIME SATURDAY...FOLLOWED BY A COLD UPPER LEVEL
TROUGH. CONCUR WITH HPC THINKING THAT THIS SCENARIO SHOULD LIKELY
PROVIDE A FRONTAL BAND OF SHOWERS SATURDAY...AND LINGERING
SCATTERED COLD POOL INSTABILITY SHOWERS SUNDAY.
TEMPERATURES CAN BE AS MUCH AS 5 TO 10 DEGREES COOLER THAN NORMAL
FOR THIS FIRST WEEKEND OF AUTUMN.
ENSUING HIGH PRESSURE WILL PROVIDE DRY CONDITIONS MONDAY AND TUESDAY
BUT TEMPERATURES SHOULD REMAIN COOLER THAN NORMAL.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
RECENT RADAR AND SURFACE DATA...COUPLED WITH RECENT HRRR AND NAM
MODEL OUTPUT SHOWS A COLD FRONTAL BAND OF MAINLY MVFR SHOWERS WILL
PASS EASTWARD THROUGH THE UPPER OHIO VALLEY THROUGH 22Z.
SURFACE WINDS WILL BECOME WEST TO NORTHWEST WITH THE COLD FRONTAL
PASSAGE WITH GUSTS UP TO 25 KTS POSSIBLE.
CONCUR WITH NAM MODEL PROFILES AND GFS LAMP THAT POST SYSTEM COLD
POOL STRATOCUMULUS CEILINGS WILL BE MAINLY AT VFR LEVELS TONIGHT AND
DAYTIME WEDNESDAY.
SURFACE WINDS TONIGHT AND WEDNESDAY WILL BE MAINLY NORTHWEST AT NO
MORE THAN 12 KTS.
.OUTLOOK /WEDNESDAY NIGHT THROUGH SUNDAY/...
EXPECT PREVALENT VFR DUE TO HIGH PRESSURE SUBSIDENCE AND DRYING INTO
FRIDAY...ALTHOUGH A BRIEF PERIOD OF RESTRICTIONS DUE TO EARLY
MORNING FOG CANNOT BE RULED OUT. RESTRICTIONS WILL BECOME COMMON
FRIDAY NIGHT INTO SUNDAY DUE TO SHOWERS ASSOCIATED WITH THE PASSAGE
OF A COLD FRONT SATURDAY AND ENSUING COLD POOL INSTABILITY SUNDAY.
ANY REMAINING MVFR POST SYSTEM COLD POOL STRATOCUMULUS SHOULD LIFT
TO VFR LEVELS BY LATE WEDNESDAY MORNING. THEREAFTER...HIGH PRESSURE
WILL SUSTAIN DRY VFR INTO FRIDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
15/11
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1258 PM EDT TUE SEP 18 2012
.AVIATION...
//DISCUSSION...
VISIBLE SATELLITE IMAGERY SHOWS MICHIGAN`S LOWER PENINSULA SHROUDED
IN MVFR STRATOCU THIS AFTERNOON AS LAKE INSTABILITY HAS DEVELOPED IN
THE WAKE OF LAST NIGHT`S COLD FRONT. DIURNAL HEATING HAS ALLOWED FOR
AN ACCELERATED EXPANSION TO THE SOUTHEAST WHICH SUGGESTS A HIGH
PROBABILITY THAT THESE CLOUDS WILL WORK INTO THE DETROIT AREA
INCLUDING DTW. BRISK NORTHWEST FLOW WITHIN THE CONVECTIVE BOUNDARY
LAYER SHOULD MAINTAIN MVFR CEILINGS INTO THE EVENING BEFORE SURFACE
HIGH PRESSURE BUILDS INTO THE AREA FROM THE WEST. THE EXPECTATION IS
THAT STRATOCU WILL BEGIN TO DISSIPATE AFTER 21Z FROM PTK SOUTHWARD
AS THIS OCCURS. FOR AREAS TO THE NORTH, IT MAY TAKE UNTIL DRY AIR
WORKS OVER LAKE MICHIGAN AND THE LOW LEVEL FLOW WEAKENS LATE TONIGHT
AROUND 06Z. THE TAFS WILL REFLECT THIS EXPECTATION. NORTHWEST WINDS
WILL GUST TO AROUND 20 KNOTS UNTIL THE ONSET OF NOCTURNAL COOLING.
//DTW THRESHOLD THREATS...
* HIGH CONFIDENCE IN CEILINGS BELOW 5000 FEET BEFORE 21Z. LOW
CONFIDENCE BETWEEN 21Z AND 03Z.
&&
.PREV DISCUSSION...ISSUED 341 AM EDT TUE SEP 18 2012
SHORT TERM...TODAY AND TONIGHT
A COLD FRONT CONTINUES TO MAKE STEADY PROGRESS EASTWARD THROUGH THE
CENTRAL GREAT LAKES REGION. SURFACE OBSERVATIONS SHOW THIS COLD
FRONT EXTENDING FROM THE SAGINAW VALLEY SOUTHWARD TO JACKSON
MICHIGAN AS OF 07Z. THE 3KM HRRR MODEL SHOWS THIS FRONT CLEARING THE
CWA AROUND 10Z WITH COOLER DRIER AIR FILTERING IN FROM THE NORTHWEST
BEHIND THE FRONT. THE LATE PUSH OF COLD AIR WILL MEAN HIGH
TEMPERATURES WILL LIKELY OCCUR EARLY THIS MORNING...WITH FALLING
MORNING TEMPERATURES AND A MODEST REBOUND DURING THE AFTERNOON
HOURS. MOST LOCATIONS WILL SEE TEMPERATURES STAYING WITHIN A NARROW
RANGE DURING THE DAYTIME HOURS AS COLD AIR ADVECTION FIGHTS THE
NORMAL BOUNCE AFFORDED BY DIURNAL HEATING. UPSTREAM OBSERVATIONS
SHOW THE LIGHTNING ACTIVITY PREVIOUSLY ASSOCIATED WITH THE SHOWERS
BEHIND THE FRONT HAS DISAPPEARED...WITH NOT MUCH IN THE WAY OF
ELEVATED CAPE OVER SOUTHEAST MICHIGAN WILL REMOVE THE REMAINING
THUNDER PREVIOUSLY ASSOCIATED WITH THIS ACTIVITY.
WINDS WILL TURN NORTHWESTERLY AND BE QUITE GUSTY BEHIND THE FRONT
WITH GUSTS TO 30 MPH. TOOK DOWN PRECIPITATION CHANCES ACROSS THE
EASTERN CWA DURING THE MORNING HOURS AS HIGH QPF AMOUNTS SHOWN BY
THE NWP MODELS IS NOT SUPPORTED BY UPSTREAM OBSERVATIONS WITH
RAPIDLY FALLING DEW POINTS INTO THE 40S BEHIND THE FRONT AND
REGIONAL RADAR REFLECTIVITY SEVERELY LACKING IN COVERAGE ACROSS THE
CENTRAL GREAT LAKES. THE BEST MOISTURE AND RAIN COVERAGE IS
CURRENTLY OVER THE OHIO VALLEY SHOULD STAY THERE DESPITE THE HEALTHY
VORT MAX OVER THE UPPER MISSISSIPPI VALLEY FORECAST TO TRACK THROUGH
THE CENTRAL GREAT LAKES DURING THE DAYTIME HOURS. WATER VAPOR
IMAGERY SHOWS A LOT OF DRY AIR EMBEDDED WITH THIS SHORTWAVE WITH THE
BEST MOISTURE BEING SCOURED OUT BY THE COLD FRONT CURRENTLY TRACKING
THROUGH THE CENTRAL GREAT LAKES. WHILE THE SHORTWAVE WILL PRODUCE
SOME SHOWER ACTIVITY...IT IS WORTHY OF A CHANCY MENTION INSTEAD OF
LIKELY POPS GIVEN THE LACK OF MOISTURE AND FAILURE OF THE SHORTWAVE
TO TRACK THROUGH WHEN WE STILL HAVE DECENT MOISTURE ACROSS THE
REGION.
SKIES WILL CLEAR OUT TONIGHT AS THIS SHORTWAVE TRACKS EAST AND
RIDGING MAKES ITS WAY THROUGH THE CENTRAL GREAT LAKES. THE ABUNDANT
RADIATIONAL COOLING AND VERY COLD TEMPERATURES IN PLACE OVER THE
CENTRAL GREAT LAKES WILL ALLOW OVERNIGHT TEMPERATURES TO TUMBLE INTO
THE UPPER 30S AND LOWER 40S. WHILE SOME LOCATIONS WILL FALL INTO THE
MIDDLE 30S...WINDS SHOULD STAY UP ENOUGH WITH THE PRESSURE GRADIENT
TO PREVENT MUCH IN THE WAY OF FROST FROM FORMING.
LONG TERM...WEDNESDAY THROUGH MONDAY
THE STRENGTH OF THE UPPER LEVEL LOW HEIGHT/POTENTIAL VORTICITY
ANOMALIES...BOTH TO THE EAST AND WEST OF LOWER MICHIGAN...MEANS THE
AREA WILL BE POSITIONED WITHIN A WEAKNESS OR COL OF THE MEAN UPPER
LEVEL TROUGH ON WEDNESDAY. WITH NO ALTERNATIVE...SOUTHEASTERN
MICHIGAN WILL FEEL THE EFFECTS OF A COLUMN THAT HAD BEEN HEAVILY
MODULATED BY SUBSIDENCE. ORIENTATION OF THE UPSTREAM UPPER LEVEL JET
AXIS ALONG WITH STRONG UPPER LEVEL WIND MAGNITUDES SUGGESTS THE NEXT
UPPER LEVEL SYSTEM WILL BE AT THE DOORSTEP OF THE AREA AT 00Z
THURSDAY. MODEL SOUNDINGS DO SHOW SOME FAIRLY STEEP 700-500MB LAPSE
RATES ARRIVING OVER THE TRI CITIES IN THE 22-01Z TIMEFRAME.
HOWEVER...LACK OF MODELED UVV IN THAT SLAB ALONG WITH UNSATURATED
CONDITIONS IN THE LOWEST 7500 FT PRECLUDES ANY INTRODUCTION OF POPS.
CLOUDS WILL BE ABSENT A BETTER PART OF THE DAY BEFORE INCREASING
VERY LATE. HIGHS WEDNESDAY ARE EXPECTED TO RISE COMFORTABLY IN THE
MIDDLE 60S.
THE AFOREMENTIONED ORIENTATION OF THE UPPER LEVEL JET AXIS ALONG
WITH THE VERY FAVORABLE BULLWHIP PATTERN(18Z WED-00Z THUR) ARE BIG
INDICATORS THE WEDNESDAY NIGHT/THURSDAY SYSTEM WILL HAVE A GREAT DEAL
OF DYNAMICS. THE LEFT EXIT CURL ALONG WITH SHARP NOSE OF THE LOW TO
MIDLEVEL THETA E RIDGE SUGGESTS THE BEST FORCING/SURFACE LOW WILL
LIFT NORTHEASTWARD FROM WESTERN WISCONSIN 00Z-THURSDAY TO A HUNDRED
MILES OR SO NORTH OF LAKE HURON BY 12Z-THURSDAY. PLAN VIEW
DEPICTIONS OF A NUMBER OF PARAMETERS ALL POINT TO A RATHER SHARP
LOWER TROPOSPHERIC FRONT WHISTLING THROUGH. SYSTEM RELATIVE
ISENTROPIC ASCENT AND FRONTOGENESIS ARE NOT AS STRONG AS ONE WOULD
LIKE TO SEE...BUT DEPTH OF DEFORMATION AND CONVERGENCE ARE GOOD FOR
MID TO HIGH CHANCE POPS IN MANY AREAS. THE FRONT BECOMES RATHER
SLUGGISH AND LINGERS THROUGHOUT THE MORNING ON THURSDAY. WILL CARRY
A LOW BLANKET POP WEDNESDAY NIGHT FOR THE DETROIT AREAS...BUT ONE
CAN GET THE SENSE THAT DETROIT MAY BE PRECIPITATION FREE UNTIL THE
14-18Z TIMEFRAME AS THINNING 700MB THETA E AXIS EVENTUALLY SLIDES IN
OVERHEAD. FELT COMFORTABLE GOING WITH A WARMER END BLEND FOR HIGHS
ON THURSDAY...UPPER 60S TO AROUND 70 DEGREES. ANOTHER ROUND OF
REMNANT SUBSIDENCE IS SHOWN TO SPREAD ACROSS THE AREA THURSDAY
AFTERNOON...KEEPING CONDITIONS DRY FOR THURSDAY NIGHT.
MARINE...
A STRONG COLD FRONT WILL SHIFT WINDS TO THE NORTHWEST AS WIND SPEEDS
INCREASE TO 25 TO 30 KNOTS ACROSS MUCH OF LAKE HURON AND 20 TO 25
KNOTS ELSEWHERE. SIGNIFICANT WAVE HEIGHTS WILL INCREASE ACCORDINGLY
TODAY FEATURING SEVERAL HOURS OF 6 TO 9 FOOT WAVES OVER THE OPEN
WATERS OF SOUTHERN LAKE HURON AND 5 TO 7 FEET FROM OUTER SAGINAW BAY
TO PORT HURON. SMALL CRAFT ADVISORIES HAVE THEREFORE BEEN ISSUED FOR
ALL OF THE NEARSHORE ZONES. WINDS COULD BRIEFLY APPROACH GALE
CONDITIONS TODAY ACROSS SOUTHERN LAKE HURON...HOWEVER THE TIME
WINDOW APPEARS TOO BRIEF AND MARGINAL TO ISSUE GALE WARNINGS AT THIS
TIME. WINDS WILL SLOWLY SUBSIDE TONIGHT AND WEDNESDAY...WITH SMALL
CRAFT ADVISORIES BEING DROPPED TONIGHT THROUGH WEDNESDAY MORNING AS
WINDS AND WAVES SLOWLY SUBSIDE. THE PATTERN WILL REMAIN ACTIVE WITH
SEVERAL EPISODES OF GUSTY NORTHWEST FLOW AND ELEVATED WAVE
CONDITIONS LIKELY THROUGH THE FORECAST PERIOD.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...
SMALL CRAFT ADVISORY...OUTER SAGINAW BAY AND THE NEARSHORE WATERS
FROM PORT AUSTIN TO HARBOR BEACH...UNTIL NOON WEDNESDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM HARBOR BEACH TO PORT
HURON...UNTIL 8 AM WEDNESDAY.
SMALL CRAFT ADVISORY...INNER SAGINAW BAY...UNTIL MIDNIGHT WEDNESDAY.
LAKE ST CLAIR...
SMALL CRAFT ADVISORY...UNTIL 10 PM TUESDAY.
MI WATERS OF LAKE ERIE...
SMALL CRAFT ADVISORY...UNTIL 10 PM TUESDAY.
&&
$$
AVIATION.....JVC
SHORT TERM...KURIMSKI
LONG TERM....CB
MARINE.......KURIMSKI
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
714 AM EDT TUE SEP 18 2012
.AVIATION...
//DISCUSSION...
A COLD FRONT HAS PASSED THROUGH ALL OF THE TAF SITES THIS
MORNING...WITH LINGERING SHOWERS AND STRATUS BEHIND THE
FRONT...OCCASIONALLY FALLING TO IFR. SEVERAL HOURS AFTER THE FRONT
PASSES CONDITIONS ARE EXPECTED TO BRIEFLY IMPROVE TO VFR...BEFORE
FALLING BACK TO MVFR WITH ADDITIONAL SHOWERS THROUGH THE EARLY
AFTERNOON. VERY GUSTY NORTHWEST WINDS WILL DEVELOP LATER THIS
MORNING ONCE THE INVERSION BREAKS...WITH GUSTS TO 20 TO 25 KNOTS.
RIDGING WILL CLEAR SKIES OUT THIS EVENING...AS A LOOSER PRESSURE
GRADIENT BRINGS WINDS DOWN BELOW 10 KNOTS THROUGH THE OVERNIGHT
HOURS.
FOR DTW...SCATTERED SHOWERS AND IFR STRATUS WILL LINGER BEHIND THE
COLD FRONT DURING THE MORNING HOURS...AS NORTHWEST WINDS INCREASE TO
10 TO 20 KNOTS BY 13Z. CONDITIONS WILL IMPROVE TO MVFR THROUGH THE
MORNING...EVENTUALLY INCREASING TO VFR LATE THIS AFTERNOON AS COOL
DRY AIR SCOURS OUT THE LOW LEVEL MOISTURE.
//DTW THRESHOLD THREATS...
* HIGH CONFIDENCE IN CEILINGS BELOW 5000 FT THIS MORNING INTO EARLY
AFTERNOON.
&&
.PREV DISCUSSION...ISSUED 341 AM EDT TUE SEP 18 2012
SHORT TERM...TODAY AND TONIGHT
A COLD FRONT CONTINUES TO MAKE STEADY PROGRESS EASTWARD THROUGH THE
CENTRAL GREAT LAKES REGION. SURFACE OBSERVATIONS SHOW THIS COLD
FRONT EXTENDING FROM THE SAGINAW VALLEY SOUTHWARD TO JACKSON
MICHIGAN AS OF 07Z. THE 3KM HRRR MODEL SHOWS THIS FRONT CLEARING THE
CWA AROUND 10Z WITH COOLER DRIER AIR FILTERING IN FROM THE NORTHWEST
BEHIND THE FRONT. THE LATE PUSH OF COLD AIR WILL MEAN HIGH
TEMPERATURES WILL LIKELY OCCUR EARLY THIS MORNING...WITH FALLING
MORNING TEMPERATURES AND A MODEST REBOUND DURING THE AFTERNOON
HOURS. MOST LOCATIONS WILL SEE TEMPERATURES STAYING WITHIN A NARROW
RANGE DURING THE DAYTIME HOURS AS COLD AIR ADVECTION FIGHTS THE
NORMAL BOUNCE AFFORDED BY DIURNAL HEATING. UPSTREAM OBSERVATIONS
SHOW THE LIGHTNING ACTIVITY PREVIOUSLY ASSOCIATED WITH THE SHOWERS
BEHIND THE FRONT HAS DISAPPEARED...WITH NOT MUCH IN THE WAY OF
ELEVATED CAPE OVER SOUTHEAST MICHIGAN WILL REMOVE THE REMAINING
THUNDER PREVIOUSLY ASSOCIATED WITH THIS ACTIVITY.
WINDS WILL TURN NORTHWESTERLY AND BE QUITE GUSTY BEHIND THE FRONT
WITH GUSTS TO 30 MPH. TOOK DOWN PRECIPITATION CHANCES ACROSS THE
EASTERN CWA DURING THE MORNING HOURS AS HIGH QPF AMOUNTS SHOWN BY
THE NWP MODELS IS NOT SUPPORTED BY UPSTREAM OBSERVATIONS WITH
RAPIDLY FALLING DEW POINTS INTO THE 40S BEHIND THE FRONT AND
REGIONAL RADAR REFLECTIVITY SEVERELY LACKING IN COVERAGE ACROSS THE
CENTRAL GREAT LAKES. THE BEST MOISTURE AND RAIN COVERAGE IS
CURRENTLY OVER THE OHIO VALLEY SHOULD STAY THERE DESPITE THE HEALTHY
VORT MAX OVER THE UPPER MISSISSIPPI VALLEY FORECAST TO TRACK THROUGH
THE CENTRAL GREAT LAKES DURING THE DAYTIME HOURS. WATER VAPOR
IMAGERY SHOWS A LOT OF DRY AIR EMBEDDED WITH THIS SHORTWAVE WITH THE
BEST MOISTURE BEING SCOURED OUT BY THE COLD FRONT CURRENTLY TRACKING
THROUGH THE CENTRAL GREAT LAKES. WHILE THE SHORTWAVE WILL PRODUCE
SOME SHOWER ACTIVITY...IT IS WORTHY OF A CHANCY MENTION INSTEAD OF
LIKELY POPS GIVEN THE LACK OF MOISTURE AND FAILURE OF THE SHORTWAVE
TO TRACK THROUGH WHEN WE STILL HAVE DECENT MOISTURE ACROSS THE
REGION.
SKIES WILL CLEAR OUT TONIGHT AS THIS SHORTWAVE TRACKS EAST AND
RIDGING MAKES ITS WAY THROUGH THE CENTRAL GREAT LAKES. THE ABUNDANT
RADIATIONAL COOLING AND VERY COLD TEMPERATURES IN PLACE OVER THE
CENTRAL GREAT LAKES WILL ALLOW OVERNIGHT TEMPERATURES TO TUMBLE INTO
THE UPPER 30S AND LOWER 40S. WHILE SOME LOCATIONS WILL FALL INTO THE
MIDDLE 30S...WINDS SHOULD STAY UP ENOUGH WITH THE PRESSURE GRADIENT
TO PREVENT MUCH IN THE WAY OF FROST FROM FORMING.
LONG TERM...WEDNESDAY THROUGH MONDAY
THE STRENGTH OF THE UPPER LEVEL LOW HEIGHT/POTENTIAL VORTICITY
ANOMALIES...BOTH TO THE EAST AND WEST OF LOWER MICHIGAN...MEANS THE
AREA WILL BE POSITIONED WITHIN A WEAKNESS OR COL OF THE MEAN UPPER
LEVEL TROUGH ON WEDNESDAY. WITH NO ALTERNATIVE...SOUTHEASTERN
MICHIGAN WILL FEEL THE EFFECTS OF A COLUMN THAT HAD BEEN HEAVILY
MODULATED BY SUBSIDENCE. ORIENTATION OF THE UPSTREAM UPPER LEVEL JET
AXIS ALONG WITH STRONG UPPER LEVEL WIND MAGNITUDES SUGGESTS THE NEXT
UPPER LEVEL SYSTEM WILL BE AT THE DOORSTEP OF THE AREA AT 00Z
THURSDAY. MODEL SOUNDINGS DO SHOW SOME FAIRLY STEEP 700-500MB LAPSE
RATES ARRIVING OVER THE TRI CITIES IN THE 22-01Z TIMEFRAME.
HOWEVER...LACK OF MODELED UVV IN THAT SLAB ALONG WITH UNSATURATED
CONDITIONS IN THE LOWEST 7500 FT PRECLUDES ANY INTRODUCTION OF POPS.
CLOUDS WILL BE ABSENT A BETTER PART OF THE DAY BEFORE INCREASING
VERY LATE. HIGHS WEDNESDAY ARE EXPECTED TO RISE COMFORTABLY IN THE
MIDDLE 60S.
THE AFOREMENTIONED ORIENTATION OF THE UPPER LEVEL JET AXIS ALONG
WITH THE VERY FAVORABLE BULLWHIP PATTERN(18Z WED-00Z THUR) ARE BIG
INDICATORS THE WEDNESDAY NIGHT/THURSDAY SYSTEM WILL HAVE A GREAT DEAL
OF DYNAMICS. THE LEFT EXIT CURL ALONG WITH SHARP NOSE OF THE LOW TO
MIDLEVEL THETA E RIDGE SUGGESTS THE BEST FORCING/SURFACE LOW WILL
LIFT NORTHEASTWARD FROM WESTERN WISCONSIN 00Z-THURSDAY TO A HUNDRED
MILES OR SO NORTH OF LAKE HURON BY 12Z-THURSDAY. PLAN VIEW
DEPICTIONS OF A NUMBER OF PARAMETERS ALL POINT TO A RATHER SHARP
LOWER TROPOSPHERIC FRONT WHISTLING THROUGH. SYSTEM RELATIVE
ISENTROPIC ASCENT AND FRONTOGENESIS ARE NOT AS STRONG AS ONE WOULD
LIKE TO SEE...BUT DEPTH OF DEFORMATION AND CONVERGENCE ARE GOOD FOR
MID TO HIGH CHANCE POPS IN MANY AREAS. THE FRONT BECOMES RATHER
SLUGGISH AND LINGERS THROUGHOUT THE MORNING ON THURSDAY. WILL CARRY
A LOW BLANKET POP WEDNESDAY NIGHT FOR THE DETROIT AREAS...BUT ONE
CAN GET THE SENSE THAT DETROIT MAY BE PRECIPITATION FREE UNTIL THE
14-18Z TIMEFRAME AS THINNING 700MB THETA E AXIS EVENTUALLY SLIDES IN
OVERHEAD. FELT COMFORTABLE GOING WITH A WARMER END BLEND FOR HIGHS
ON THURSDAY...UPPER 60S TO AROUND 70 DEGREES. ANOTHER ROUND OF
REMNANT SUBSIDENCE IS SHOWN TO SPREAD ACROSS THE AREA THURSDAY
AFTERNOON...KEEPING CONDITIONS DRY FOR THURSDAY NIGHT.
MARINE...
A STRONG COLD FRONT WILL SHIFT WINDS TO THE NORTHWEST AS WIND SPEEDS
INCREASE TO 25 TO 30 KNOTS ACROSS MUCH OF LAKE HURON AND 20 TO 25
KNOTS ELSEWHERE. SIGNIFICANT WAVE HEIGHTS WILL INCREASE ACCORDINGLY
TODAY FEATURING SEVERAL HOURS OF 6 TO 9 FOOT WAVES OVER THE OPEN
WATERS OF SOUTHERN LAKE HURON AND 5 TO 7 FEET FROM OUTER SAGINAW BAY
TO PORT HURON. SMALL CRAFT ADVISORIES HAVE THEREFORE BEEN ISSUED FOR
ALL OF THE NEARSHORE ZONES. WINDS COULD BRIEFLY APPROACH GALE
CONDITIONS TODAY ACROSS SOUTHERN LAKE HURON...HOWEVER THE TIME
WINDOW APPEARS TOO BRIEF AND MARGINAL TO ISSUE GALE WARNINGS AT THIS
TIME. WINDS WILL SLOWLY SUBSIDE TONIGHT AND WEDNESDAY...WITH SMALL
CRAFT ADVISORIES BEING DROPPED TONIGHT THROUGH WEDNESDAY MORNING AS
WINDS AND WAVES SLOWLY SUBSIDE. THE PATTERN WILL REMAIN ACTIVE WITH
SEVERAL EPISODES OF GUSTY NORTHWEST FLOW AND ELEVATED WAVE
CONDITIONS LIKELY THROUGH THE FORECAST PERIOD.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...
SMALL CRAFT ADVISORY...OUTER SAGINAW BAY AND THE NEARSHORE WATERS
FROM PORT AUSTIN TO HARBOR BEACH...UNTIL NOON WEDNESDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM HARBOR BEACH TO PORT
SANILAC...UNTIL 8 AM WEDNESDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM PORT SANILAC TO PORT
HURON...FROM 11 AM TUESDAY TO 8 AM WEDNESDAY.
SMALL CRAFT ADVISORY...INNER SAGINAW BAY...FROM 11 AM TUESDAY TO
MIDNIGHT WEDNESDAY.
LAKE ST CLAIR...
SMALL CRAFT ADVISORY...FROM 11 AM TUESDAY TO 10 PM TUESDAY.
MI WATERS OF LAKE ERIE...
SMALL CRAFT ADVISORY...FROM 11 AM TUESDAY TO 10 PM TUESDAY.
&&
$$
AVIATION.....KURIMSKI
SHORT TERM...KURIMSKI
LONG TERM....CB
MARINE.......KURIMSKI
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
341 AM EDT TUE SEP 18 2012
.SHORT TERM...TODAY AND TONIGHT
A COLD FRONT CONTINUES TO MAKE STEADY PROGRESS EASTWARD THROUGH THE
CENTRAL GREAT LAKES REGION. SURFACE OBSERVATIONS SHOW THIS COLD
FRONT EXTENDING FROM THE SAGINAW VALLEY SOUTHWARD TO JACKSON
MICHIGAN AS OF 07Z. THE 3KM HRRR MODEL SHOWS THIS FRONT CLEARING THE
CWA AROUND 10Z WITH COOLER DRIER AIR FILTERING IN FROM THE NORTHWEST
BEHIND THE FRONT. THE LATE PUSH OF COLD AIR WILL MEAN HIGH
TEMPERATURES WILL LIKELY OCCUR EARLY THIS MORNING...WITH FALLING
MORNING TEMPERATURES AND A MODEST REBOUND DURING THE AFTERNOON
HOURS. MOST LOCATIONS WILL SEE TEMPERATURES STAYING WITHIN A NARROW
RANGE DURING THE DAYTIME HOURS AS COLD AIR ADVECTION FIGHTS THE
NORMAL BOUNCE AFFORDED BY DIURNAL HEATING. UPSTREAM OBSERVATIONS
SHOW THE LIGHTNING ACTIVITY PREVIOUSLY ASSOCIATED WITH THE SHOWERS
BEHIND THE FRONT HAS DISAPPEARED...WITH NOT MUCH IN THE WAY OF
ELEVATED CAPE OVER SOUTHEAST MICHIGAN WILL REMOVE THE REMAINING
THUNDER PREVIOUSLY ASSOCIATED WITH THIS ACTIVITY.
WINDS WILL TURN NORTHWESTERLY AND BE QUITE GUSTY BEHIND THE FRONT
WITH GUSTS TO 30 MPH. TOOK DOWN PRECIPITATION CHANCES ACROSS THE
EASTERN CWA DURING THE MORNING HOURS AS HIGH QPF AMOUNTS SHOWN BY
THE NWP MODELS IS NOT SUPPORTED BY UPSTREAM OBSERVATIONS WITH
RAPIDLY FALLING DEW POINTS INTO THE 40S BEHIND THE FRONT AND
REGIONAL RADAR REFLECTIVITY SEVERELY LACKING IN COVERAGE ACROSS THE
CENTRAL GREAT LAKES. THE BEST MOISTURE AND RAIN COVERAGE IS
CURRENTLY OVER THE OHIO VALLEY SHOULD STAY THERE DESPITE THE HEALTHY
VORT MAX OVER THE UPPER MISSISSIPPI VALLEY FORECAST TO TRACK THROUGH
THE CENTRAL GREAT LAKES DURING THE DAYTIME HOURS. WATER VAPOR
IMAGERY SHOWS A LOT OF DRY AIR EMBEDDED WITH THIS SHORTWAVE WITH THE
BEST MOISTURE BEING SCOURED OUT BY THE COLD FRONT CURRENTLY TRACKING
THROUGH THE CENTRAL GREAT LAKES. WHILE THE SHORTWAVE WILL PRODUCE
SOME SHOWER ACTIVITY...IT IS WORTHY OF A CHANCY MENTION INSTEAD OF
LIKELY POPS GIVEN THE LACK OF MOISTURE AND FAILURE OF THE SHORTWAVE
TO TRACK THROUGH WHEN WE STILL HAVE DECENT MOISTURE ACROSS THE
REGION.
SKIES WILL CLEAR OUT TONIGHT AS THIS SHORTWAVE TRACKS EAST AND
RIDGING MAKES ITS WAY THROUGH THE CENTRAL GREAT LAKES. THE ABUNDANT
RADIATIONAL COOLING AND VERY COLD TEMPERATURES IN PLACE OVER THE
CENTRAL GREAT LAKES WILL ALLOW OVERNIGHT TEMPERATURES TO TUMBLE INTO
THE UPPER 30S AND LOWER 40S. WHILE SOME LOCATIONS WILL FALL INTO THE
MIDDLE 30S...WINDS SHOULD STAY UP ENOUGH WITH THE PRESSURE GRADIENT
TO PREVENT MUCH IN THE WAY OF FROST FROM FORMING.
&&
.LONG TERM...WEDNESDAY THROUGH MONDAY
THE STRENGTH OF THE UPPER LEVEL LOW HEIGHT/POTENTIAL VORTICITY
ANOMALIES...BOTH TO THE EAST AND WEST OF LOWER MICHIGAN...MEANS THE
AREA WILL BE POSITIONED WITHIN A WEAKNESS OR COL OF THE MEAN UPPER
LEVEL TROUGH ON WEDNESDAY. WITH NO ALTERNATIVE...SOUTHEASTERN
MICHIGAN WILL FEEL THE EFFECTS OF A COLUMN THAT HAD BEEN HEAVILY
MODULATED BY SUBSIDENCE. ORIENTATION OF THE UPSTREAM UPPER LEVEL JET
AXIS ALONG WITH STRONG UPPER LEVEL WIND MAGNITUDES SUGGESTS THE NEXT
UPPER LEVEL SYSTEM WILL BE AT THE DOORSTEP OF THE AREA AT 00Z
THURSDAY. MODEL SOUNDINGS DO SHOW SOME FAIRLY STEEP 700-500MB LAPSE
RATES ARRIVING OVER THE TRI CITIES IN THE 22-01Z TIMEFRAME.
HOWEVER...LACK OF MODELED UVV IN THAT SLAB ALONG WITH UNSATURATED
CONDITIONS IN THE LOWEST 7500 FT PRECLUDES ANY INTRODUCTION OF POPS.
CLOUDS WILL BE ABSENT A BETTER PART OF THE DAY BEFORE INCREASING
VERY LATE. HIGHS WEDNESDAY ARE EXPECTED TO RISE COMFORTABLY IN THE
MIDDLE 60S.
THE AFOREMENTIONED ORIENTATION OF THE UPPER LEVEL JET AXIS ALONG
WITH THE VERY FAVORABLE BULLWHIP PATTERN(18Z WED-00Z THUR) ARE BIG
INDICATORS THE WEDNESDAY NIGHT/THURSDAY SYSTEM WILL HAVE A GREAT DEAL
OF DYNAMICS. THE LEFT EXIT CURL ALONG WITH SHARP NOSE OF THE LOW TO
MIDLEVEL THETA E RIDGE SUGGESTS THE BEST FORCING/SURFACE LOW WILL
LIFT NORTHEASTWARD FROM WESTERN WISCONSIN 00Z-THURSDAY TO A HUNDRED
MILES OR SO NORTH OF LAKE HURON BY 12Z-THURSDAY. PLAN VIEW
DEPICTIONS OF A NUMBER OF PARAMETERS ALL POINT TO A RATHER SHARP
LOWER TROPOSPHERIC FRONT WHISTLING THROUGH. SYSTEM RELATIVE
ISENTROPIC ASCENT AND FRONTOGENESIS ARE NOT AS STRONG AS ONE WOULD
LIKE TO SEE...BUT DEPTH OF DEFORMATION AND CONVERGENCE ARE GOOD FOR
MID TO HIGH CHANCE POPS IN MANY AREAS. THE FRONT BECOMES RATHER
SLUGGISH AND LINGERS THROUGHOUT THE MORNING ON THURSDAY. WILL CARRY
A LOW BLANKET POP WEDNESDAY NIGHT FOR THE DETROIT AREAS...BUT ONE
CAN GET THE SENSE THAT DETROIT MAY BE PRECIPITATION FREE UNTIL THE
14-18Z TIMEFRAME AS THINNING 700MB THETA E AXIS EVENTUALLY SLIDES IN
OVERHEAD. FELT COMFORTABLE GOING WITH A WARMER END BLEND FOR HIGHS
ON THURSDAY...UPPER 60S TO AROUND 70 DEGREES. ANOTHER ROUND OF
REMNANT SUBSIDENCE IS SHOWN TO SPREAD ACROSS THE AREA THURSDAY
AFTERNOON...KEEPING CONDITIONS DRY FOR THURSDAY NIGHT.
&&
.MARINE...
A STRONG COLD FRONT WILL SHIFT WINDS TO THE NORTHWEST AS WIND SPEEDS
INCREASE TO 25 TO 30 KNOTS ACROSS MUCH OF LAKE HURON AND 20 TO 25
KNOTS ELSEWHERE. SIGNIFICANT WAVE HEIGHTS WILL INCREASE ACCORDINGLY
TODAY FEATURING SEVERAL HOURS OF 6 TO 9 FOOT WAVES OVER THE OPEN
WATERS OF SOUTHERN LAKE HURON AND 5 TO 7 FEET FROM OUTER SAGINAW BAY
TO PORT HURON. SMALL CRAFT ADVISORIES HAVE THEREFORE BEEN ISSUED FOR
ALL OF THE NEARSHORE ZONES. WINDS COULD BRIEFLY APPROACH GALE
CONDITIONS TODAY ACROSS SOUTHERN LAKE HURON...HOWEVER THE TIME
WINDOW APPEARS TOO BRIEF AND MARGINAL TO ISSUE GALE WARNINGS AT THIS
TIME. WINDS WILL SLOWLY SUBSIDE TONIGHT AND WEDNESDAY...WITH SMALL
CRAFT ADVISORIES BEING DROPPED TONIGHT THROUGH WEDNESDAY MORNING AS
WINDS AND WAVES SLOWLY SUBSIDE. THE PATTERN WILL REMAIN ACTIVE WITH
SEVERAL EPISODES OF GUSTY NORTHWEST FLOW AND ELEVATED WAVE
CONDITIONS LIKELY THROUGH THE FORECAST PERIOD.
&&
.AVIATION...ISSUED 1153 PM EDT MON SEP 17 2012
//DISCUSSION...
THE COLD FRONT NOW OVER THE SAGINAW AREA WILL PUSH EAST OF METRO
DETROIT BY 12Z. WHILE LINGERING INSTABILITY COULD CERTAINLY TOUCH
OFF SOME ADDITIONAL THUNDERSTORMS ALONG THE FRONT EARLY THIS
MORNING...CONFIDENCE REMAINS TOO LOW TO INCLUDE IN THE TERMINAL
FCSTS ATTM. SFC DEWPOINTS HAVE BEEN SLOWLY INCHING UPWARDS THIS
EVENING. THE ADVECTION OF THIS HIGHER MOISTURE COMBINED WITH SHALLOW
POST FRONTAL COLD AIR ADVECTION WILL SET THE STAGE FOR STRATUS
DEVELOPMENT EARLY THIS MORNING...BASES OF WHICH MAY FALL TO IFR. AS
THE DEPTH OF COLD AIR INCREASES ON TUESDAY...THERE WILL BE A SLOW
YET STEADY RISE IN CEILING HEIGHTS DURING THE COURSE OF THE DAY.
FOR DTW...A LITTLE BETTER INFLUX OF MOISTURE ALLOWED SCATTERED
SHOWERS AND FEW THUNDERSTORMS TO MOVE INTO THE METRO AREA FROM
TOLEDO THIS EVENING. THESE SHOWERS MAY LINGER OVER THE NEXT COUPLE
OF HOURS. THE NEXT CHANCE OF RAIN WILL ARRIVE AROUND 10 OR 11Z WITH
THE PASSAGE OF THE COLD FRONT. THIS FRONT WILL BE MARKED BY A WIND
SHIFT TO THE NW. RECENT MODEL SOUNDINGS AND OBSERVATIONS SUGGEST
THAT CEILINGS WILL RAPIDLY DROP TO MVFR AROUND 08Z...THEN POSSIBLY
DROP INTO THE IFR CATEGORY TOWARD DAYBREAK.
//DTW THRESHOLD THREATS...
* HIGH CONFIDENCE IN CEILINGS WILL BE BELOW 5000 FT THIS MORNING
INTO EARLY AFTERNOON.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...
SMALL CRAFT ADVISORY...OUTER SAGINAW BAY AND THE NEARSHORE WATERS
FROM PORT AUSTIN TO HARBOR BEACH...FROM 8 AM TUESDAY TO NOON
WEDNESDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM HARBOR BEACH TO PORT
SANILAC...FROM 8 AM TUESDAY TO 8 AM WEDNESDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM PORT SANILAC TO PORT
HURON...FROM 11 AM TUESDAY TO 8 AM WEDNESDAY.
SMALL CRAFT ADVISORY...INNER SAGINAW BAY...FROM 11 AM TUESDAY TO
MIDNIGHT WEDNESDAY.
LAKE ST CLAIR...
SMALL CRAFT ADVISORY...FROM 11 AM TUESDAY TO 10 PM TUESDAY.
MI WATERS OF LAKE ERIE...
SMALL CRAFT ADVISORY...FROM 11 AM TUESDAY TO 10 PM TUESDAY.
&&
$$
SHORT TERM...KURIMSKI
LONG TERM....CB
MARINE.......KURIMSKI
AVIATION.....SC
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
118 AM EDT TUE SEP 18 2012
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 423 PM EDT MON SEP 17 2012
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH AXIS
FROM HUDSON BAY INTO NW MN AND SE SOUTH DAKOTAS. A SHORTWAVE OVER NE
SD WAS MOVING INTO THE BASE OF THE TROUGH. AT THE SFC...A COLD FRONT
EXTENDED FROM NRN LOWER MI INTO SE WI. A LARGE POST-FRONTAL RAINBAND
FROM CNTRL WI INTO CNTRL UPPER MI WAS SUPPORTED BY MODERATE TO
STRONG MID LEVEL FGEN AND UPPER LEVEL DIV WITH THE RIGHT ENTRANCE OF
THE 250-300 MB JET. NRLY WINDS AND 850 MB TEMPS FALLING TO AROUND 3C
SUPPORTED HEAVIER LAKE ENHANCED RAIN SHOWERS INTO N CNTRL UPPER MI.
WITH DRIER AIR UPSTREAM OVER NE MN THE WRN CWA...OVER THE FAR WRN
CWA VCNTY IWD...HAS DIMINISHED OR ENDED.
TONIGHT...MDLS SUGGEST THAT THE STRONGER FGEN DYNAMICS WILL LIFT OFF
TO THE NE LATE THIS AFTERNOON AND EVENING. HOWEVER...WITH CAA
DROPPING 850 MB TEMPS TO NEAR -3C OVER LAKE SUPERIOR TONIGHT LEADING
TO LK-H8 DELTA/T TO AROUND 20C AND THE 700-500 MB TROUGH MOVING
IN...LAKE EFFECT RAIN SHOWERS WILL DEVELOP AND INTENSIFY OVERNIGHT
FOR LOCATIONS FAVORED BY N WINDS. WITH THE LOW FREEZING LEVEL...SOME
GRAUPEL WILL BE POSSIBLE WITH THE HEAVIER SHOWERS. LAKE INDUCED
TROUGHING WITH MORE OF AN NNE FLOW OVER THE ERN LAKE SHOULD MINIMIZE
PCPN INTO THE FAR ERN CWA. UPSLOPE FLOW WILL LEAD TO THE HIGHEST
PCPN AMOUNTS OVER THE HIGHER TERRAIN OVER MARQUETTE AND BARAGA
COUNTIES.
TUESDAY...LAKE EFFECT PCPN WILL CONTINUE WITH THE 850 MB THERMAL
TROF STILL OVER THE AREA. AS WINDS BACK AND BECOME MORE ANTICYCLONIC
AND SOME LOW LEVEL DRYING MOVES IN FROM THE WEST...THE PCPN SHOULD
DIMINISH SHOULD DIMINISH FROM WEST TO EAST. SHOWERS DOWNWIND OF LAKE
SUPERIOR BECOMING MORE SCATTERED THROUGH THE DAY FROM WEST TO EAST.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 423 PM EDT MON SEP 17 2012
TUE NGT...EXPECT LINGERING LK CLDS/-SHRA OVER MAINLY THE E HALF THRU
06Z TO END WITH APRCH OF PROGRESSIVE SHRTWV RDG/DNVA/ACCOMPANYING
DRY AIRMASS AND PASSAGE OF SFC HI PRES THAT CAUSES WSHFT TO THE SW
AND EXIT OF H85 THERMAL TROF. OTRW...LOOKS LIKE THERE SHOULD BE A
SEVERAL HOUR WINDOW OF OPTIMAL RADIATIONAL COOLING CONDITIONS ACROSS
MAINLY THE INTERIOR W AND CNTRL ACCOMPANYING THE PASSAGE OF THE RDG
AXIS/DRY AIR/LIGHT WINDS. OVER THE W...QUICKER WSHFT TO THE SW AFT
06Z WITH SHARPENING PRES GRADIENT AND SOME INCRSG HI/MID CLDS IN
ADVANCE OF NEXT SHRTWV DROPPING INTO MN WL END THE FAVORABLE COOLING
CONDITIONS WELL BEFORE SUNRISE...BUT NOT BEFORE TEMPS HAVE A CHANCE
TO CRASH BEFORE 06Z FM BLO NORMAL MAX READINGS ON TUE AFTN. OPTED TO
ISSUE FREEZE WATCH FOR THE INTERIOR W HALF...WHERE MOST GUIDANCE
SHOWS WDSPRD MIN TEMPS FALLING BLO 32.
WED...NEXT FAIRLY IMPRESSIVE SHRTWV DIVING SEWD THRU NW FLOW ALF
INTO MEAN TROF OVER ERN NAMERICA IS FCST TO MOVE NEAR UPR MI BY 00Z
THU. ALTHOUGH THE MSTR RETURN AHEAD OF THIS DISTURBANCE WL BE
ANEMIC DESPITE STRENGTHENING LLVL SLY FLOW...VIGOROUS DPVA/DEEP LYR
QVECTOR CNVGC SUPPORTS LIKELY POPS OVER THE N HALF OF THE CWA ON THE
CYC SIDE OF VORT MAX TRACK AND WHERE MOISTENING OFF LK SUP MIGHT
PLAY A ROLE.
WED NGT...DNVA/LARGER SCALE QVECTOR DVGC/HIER LVL DRYING IN THE WAKE
OF SHRTWV WL END LARGER SCALE PCPN CHCS W-E. BUT INCOMING AIRMASS WL
BE COLD ENUF WITH H85 TEMPS FCST AS LO AS 1-3C TO SUPPORT LK EFFECT
-SHRA IN AREAS IMPACTED BY FCST WNW FLOW...ESPECIALLY IF THE MORE
CYC FLOW SHOWN BY THE 12Z NAM/CNDN MODELS VERIFIES.
THU...THE ARRIVAL OF ANOTHER SHRTWV/SFC LO PRES TROF WL BRING MORE
SHRA CHCS DESPITE AN ABSENCE OF SGNFT DEEP LYR MOISTENING. QUESTIONS
ON TIMING/INTENSITY OF THIS DISTURBANCE INDICATE NO MORE THAN CHC
POPS ARE APPROPRIATE.
IN THE MEDIUM/EXTENDED RANGE...WITH MEAN TROF LINGERING OVER ERN
NAMERICA...EXPECT BLO NORMAL TEMPS TO PERSIST INTO EARLY NEXT WEEK.
MODELS SHOW A SERIES OF DISTURBANCES MOVING THRU THE MEAN TROF...SO
EXPECT SHOWERS TO PERSIST ESPECIALLY THRU SAT AND NEAR THE GREAT
LAKES. BEST CHC FOR A MORE WDSPRD RAINFALL APPEARS ON FRI WHEN
MODELS SHOW A PARTICULARLY STRONG DISTURBANCE IMPACTING THE AREA.
RECENT GFS RUNS SHOW THE MOST VIGOROUS SFC CYCLOGENESIS...AND WARM
LK WATERS MIGHT SUPPORT THAT SCENARIO. VARIOUS MODELS HINT THE UPR
TROF AXIS WL SHIFT A BIT FARTHER TO THE E NEXT SUN/MON WITH EPISODES
OF MORE ACYC FLOW/DRIER WX...BUT TIMING OF THESE FEATURES IS NOT
POSSIBLE ATTM. WL FOLLOW MODEL OF CONSENSUS LOWER POPS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 118 AM EDT TUE SEP 18 2012
A LAKE EFFECT SHRA REGIME WILL BE THE RULE FOR THE FIRST HALF OR SO
OF THIS FCST PERIOD AS CHILLY AIR MASS SETTLES OVER THE UPPER LAKES
UNDERNEATH DEEPENING MID/UPPER LEVEL TROF. AS A RESULT...CONDITIONS
WILL BE QUITE VARIABLE AS LAKE EFFECT SHRA OF VARYING INTENSITY
AFFECT KIWD/KCMX/KSAW. MORE DIRECT UPSLOPING NORTHERLY WINDS SHOULD
FAVOR KIWD/KSAW FOR MORE FREQUENT SHRA AND MVFR CONDITIONS THOUGH
LAKE AIDED TROFFING SHOULD ESPECIALLY FAVOR KSAW FOR PCPN. AT
KCMX...NORTHERLY WIND IS NOT AS FAVORABLE FOR LAKE EFFECT -SHRA/LWR
CIGS. STILL...WOULD NOT BE SURPRISED TO SEE SOME BRIEF PERIODS OF
MVFR CONDITIONS EVEN THOUGH VFR SHOULD PREVAIL. IMPROVEMENT WILL
BEGIN THIS AFTN FROM W TO E AS TROF BEGINS TO SHIFT E AND DAYTIME
HEATING DISRUPTS LAKE EFFECT PROCESSES. VFR CONDITIONS WILL BE THE
RULE BY EVENING...IF NOT SOONER.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 423 PM EDT MON SEP 17 2012
20 TO 30 KT NORTH WINDS WILL CONTINUE IN THE SHORT TERM BUT DIMINISH
LATER TUESDAY AS HIGH PRESSURE BUILDS INTO THE REGION FROM THE WEST.
WINDS WILL GRADUALLY SHIFTING TO THE NW THEN W BY TUESDAY EVENING.
WINDS WILL BECOME LIGHT FOR AWHILE ON TUE NIGHT WITH THE PASSAGE OF
A HI PRES RIDGE ACROSS THE LAKE. BUT S WINDS WILL INCREASE QUICKLY
LATER AT NIGHT OVER THE W UNDER THE SHARPENING PRES GRADIENT BETWEEN
THE QUICKLY DEPARTING RIDGE AND AN INCOMING LO PRES TROUGH. AS THIS
DEEP TROF MOVES TO THE E...S WINDS ON WED MAY REACH GALE FORCE WHERE
THIS FLOW IS TYPICALLY ENHANCED OVER THE NCENTRAL AND E. ISSUED A
GALE WATCH WED AFTERNOON/EVENING IN THIS AREA TO ACCOUNT FOR THIS
STRONG FLOW AND FAIRLY UNSTABLE CONDITIONS OVER THE WARM LAKE WATER
THAT WILL ENHANCE MIXING. FOLLOWING THE PASSAGE OF THE TROF...LOOK
FOR A WIND SHIFT TO THE WNW WITH WINDS UP TO 25 TO 30 KTS INTO THU.
DEPENDING ON THE INTENSITY OF ANOTHER DISTURBANCE MOVING THRU THE
GREAT LAKES ON FRI/SAT...A STRONGER NNW FLOW IS POSSIBLE THEN. BUT
NO GALES ARE EXPECTED AT THIS TIME.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
FREEZE WATCH FROM LATE TONIGHT THROUGH WEDNESDAY MORNING FOR
MIZ002-004-005-009>013-084.
LAKE SUPERIOR...
GALE WATCH FROM WEDNESDAY AFTERNOON THROUGH WEDNESDAY EVENING
FOR LSZ267.
GALE WATCH FROM WEDNESDAY AFTERNOON THROUGH WEDNESDAY EVENING
FOR LSZ266.
GALE WATCH FROM WEDNESDAY AFTERNOON THROUGH WEDNESDAY EVENING
FOR LSZ264.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KC
AVIATION...ROLFSON
MARINE...JLB/KC
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
615 PM EDT TUE SEP 18 2012
.SYNOPSIS...
A COLD FRONT WILL SLOWLY PUSH ACROSS THE REGION TONIGHT...WITH
RAIN AND GUSTY WINDS SUBSIDING BY LATER THIS EVENING. HIGH
PRESSURE WILL BUILD IN...BRINGING DRY WEATHER FROM WEDNESDAY
THROUGH FRIDAY.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
610PM...REMOVED ENTIRE REMAINING REGION OF TORNADO WATCH.
SIGNIFICANT CONVECTION HAS MOVED EAST OF THE REGION. WHILE SRH
VALUES REMAIN EXTREME, INSTABILITY NEVER MATERIALIZED TO SUPPORT
CONVECTION.
5PM...REMOVED WESTERN PORTION OF TORNADO WATCH WHERE
RAIN COOLED AIR AS STABILIZED ATMOSPHERE QUITE A BIT, AND WIND
SHEAR HAS DECREASED. WILL CONTINUE EASTERN PORTION FOR AT LEAST
THE NEXT HOUR.
330 PM UPDATE... WE APPEAR TO BE TRANSITIONING FROM A SVR/WIND
THREAT...TO MORE OF A HVY RAIN THREAT ATTM.
THE BACK EDGE OF THE PRE-FRNTL BAND OF RAIN/EMBEDDED TSRA IS
SLOWLY PUSHING EWD FROM ABT THE I-81 CORRIDOR LATE THIS AFTN. THE
MAIN CONCERN IS TURNING TO A TRAINING SW-NE BATCH OF
+RA/TSRA...EXTENDING FROM S-CNTRL PA UP INTO OUR SERN ZNS...SO FF
WATCHES HAVE BEEN POSTED FOR LUZERNE/LACK/WAYNE/PIKE/SULL CNTYS. SINCE
THE LEADING NRN STREAM WV IS LIFTING OUT TO THE NE THROUGH
ONT...IT WILL LIKELY TAKE THE SECOND WV COMING IN BEHIND IT FROM
WI/UPR MI...TO FINALLY KICK THE HVYR RAIN BAND EWD AFTER 00Z.
AS FOR THE WIND/SVR SITN...STG SYNOPTIC-SCALE WINDS ARE PUSHING
EWD ATTM...AND THE OVERALL WIND THREAT SHOULD BE LWRG WITH TIME
TWDS 00Z. DITTO FOR THE SVR CONVECTIVE SITN.
LTR TNT...DRIER AIR WILL ULTIMATELY PUSH IN FROM THE W...WITH POPS
DIMINISHING BY/AFTER 06Z.
PREV DISC... 1230 PM UPDATE... TOR WATCH #643 ISSUED FOR NE PA
AND SULL CNTY NY...TIL 23Z. THUS...WE`VE ADDED SOME ENHANCED
WORDING FOR THE ISOLD TSRA THIS AREA.
LINEAR FEATURES ARE BCMG MORE PROMINENT ALG THE BACK EDGE OF THE
STEADIER PCPN...AS ALLUDED TO IN PREV DISC. ML CAPES REMAIN FAIRLY
LOW...ON THE ORDER OF 100-200...BUT LOW-LVL SHEAR IS EXTREMELY
IMPRESSIVE (0-1 KM SREL HEL OF 400+). UNLESS MORE DESTAB
OCCURS...DISCRETE CELL DVLPMT IS UNLIKELY...BUT LINES OF
SHRA/EMBEDDED TSRA...WITH LOCALIZED 50+ KT GUSTS ARE PLAUSIBLE.
WE`LL CONTINUE TO MONITOR CLOSELY.
PREV DISC... 10 AM UPDATE... BROAD SWATH OF RA/+RA CONTS TO TRACK
NEWD THROUGH CNY/NE PA ATTM...BEING FUELED BY STG POS THETA-E
ADVCTN ON THE LEADING EDGE OF AN INCRG LOW-LVL JET. WE EXPECT
STEADY RAIN TO PERSIST TIL PERHAPS MID TO LATE AFTN...WHEN THE
BACK EDGE OF THE MAIN PCPN SHIELD...NOW ACRS WRN PA...ATTEMPTS TO
MOVE INTO THE CWA FROM SW TO NE. A BIG QUESTION IS WHAT HAPPENS
AFTER THAT...JUST AHD OF THE COLD FROPA IN THE 21Z-01Z TIME FRAME.
MOST OF THE CONVECTION ALLOWING MODELS (HRRR AND 4 KM WRF...FOR
EXAMPLE) INDICATE THAT SOME SORT OF ENHANCED/CONVECTIVE LN FORMS
ON THE BACK EDGE OF THE STEADIER PCPN AFTER 21Z...TRANSLATING
MAINLY ACRS NE PA AND PTNS OF THE SRN TIER LATE IN THE DAY.
THIS...OF COURSE...WILL DEPEND ON HOW MUCH INSTAB CAN FORM. THE
LATEST RUC SHOWS ML CAPE OF 200-400 THIS TIME FRAME IN OUR SERN
ZNS...WITH THE 12Z NAM COMING IN SHOWING MORE (500-800). GIVEN
EXTENSIVE CLOUD COVER/PCPN FOR SVRL MORE HRS AT LEAST...AND WHAT`S
BEING OBSERVED UPSTREAM ON SPC MESO`S ATTM (ML CAPE OF 100-200 IN
SE PA)...WE`RE INCLINED TO BUY THE MORE CONSERVATIVE RUC. ACRS
ROUGHLY THE SERN HALF OF THE CWA...WE`LL STILL MENTION ISOLD
TSRA...WHILE SHOWING OCNL +RA JUST ABT EVERYWHERE. THE BEST SVR
POTENTIAL APPEARS TO BE JUST SE OF THE CWA...WHERE THE PRIMARY
IMPETUS FOR ANY DISCERNIBLE LN OR DISCRETE CELL FORMATION IS.
KBGM VWP HAS 20-30 KT SRLY FLOW AT 2K FT AGL ATTM...WITH 40-50 KT
AT 3-4K FT AGL. KBGM BASE VEL PRODS ALSO SHOW THE 50-60 KT CORE
MOVG NWD THROUGH ERN PA...AND DESCENDING SOMEWHAT WITH TIME. THE
MOST FAVORABLE TIME FOR CONSISTENTLY STG GRADIENT WIND GUSTS WILL BE
FROM ABT 17-22Z. WIND ADVISORIES REMAIN IN TACT.
UNLESS TRAINING OF HEAVY RAIN BANDS FORM...WE`RE STILL NOT
EXPECTING ANY SIG HYDRO RELATED PROBLEMS...SO NO WATCHES PLANNED
FOR THE TIME BEING.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
340 PM UPDATE... VERY BRIEF DISCN...DUE TO ONGOING SVR WX.
DRY WX STILL ANTICIPATED WED-FRI...OTHER THAN SOME ISOLD -SHRA
EARLY WED...DUE TO A WEAK LAKE RESPONSE.
TEMPS WILL BE UNCHANGED...AS CURRENT MAX/MIN TEMP GRIDS MATCH
BLENDED MOS WELL.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
315 AM UPDATE...CURRENT FORECAST IN GOOD SHAPE, LATEST MODEL RUNS
REMAIN CONSISTENT WITH PREVIOUS CYCLE, NO SIGNIFICANT CHANGES.
PREVIOUS DISC...
FRIDAY THROUGH FRIDAY NIGHT...A DEEP CUT OFF LOW WILL MOVE INTO
THE UPPER MIDWEST DURING THIS TIME. MEANWHILE FARTHER TO THE EAST
IN OUR NECK OF THE WOODS...WE WILL REMAIN IN A DEEP SOUTHWESTERLY
FLOW AHEAD OF THE CUT OFF LOW. INITIALLY THIS WILL BE GREAT NEWS
WITH OUR AREA REMAINING DRY AND EXPERIENCING ABOVE NORMAL TEMPS.
HIGHS FRIDAY SHOULD BE WELL INTO THE 70S...WITH NEAR 80 DEGREE
READINGS ACROSS THE LAKE PLAIN.
SATURDAY AND BEYOND...THE DOWNSIDE TO THE SLOW MOVEMENT OF THE CUT OFF LOW
MENTIONED ABOVE WILL BE AN UNSETTLED WEEKEND. AS THE CUT OFF LOW
MOVES NORTHEAST AND WE BEGIN TO FEEL THE EFFECTS OF THE H5
TROF...RAIN WILL SPREAD OUR WAY LATER SATURDAY INTO SUNDAY. THE
GFS HINTS THAT WE MAY SEE A DRY SLOT LATER SUNDAY...BUT PLENTY OF
UNCERTAINTY EXISTS WITH THE EURO KEEPING US WET. WILL KEEP CHANCE
POPS IN ESPECIALLY ACROSS THE NORTH TO COVER THIS.
&&
.AVIATION /22Z TUESDAY THROUGH SUNDAY/...
OVERVIEW...MVFR CIGS AND VSBYS LIKELY TO PERSIST THROUGH 21Z AS A PRE-FRONTAL
TROF MOVES THROUGH THE TERMINALS AND WE HAVE WIDESPREAD RAIN.
AFTER THIS TIME VSBYS SHOULD IMPROVE AS THE RAIN ENDS...BUT MVFR
CIGS LIKELY TO PERSIST THROUGH EARLY TONIGHT WITH VFR THEREAFTER.
DETAILS...A LINE OF HEAVIER RAIN IS MOVING ACROSS THE TERMINALS NOW...WELL
AHEAD OF A COLD FRONT OVER WESTERN NY. MVFR CIGS AND VSBYS LIKELY
WITH THE RAIN THROUGH 21Z. SOME BRIEF IFR VSBYS POSSIBLE AT
KRME...KBGM...KAVP DUE TO HEAVIER RAIN DURING THIS TIME. IN
ADDITION SOME PERIODS OF VFR LIKELY AT KRME/KSYR/KAVP DUE TO
STRONG DOWNSLOPING WINDS (SOUTHEAST). ONCE THIS LINE MOVES EAST OF
THE AREA AFTER 21Z...VSBYS WILL IMPROVE TO VFR BUT MVFR CIGS WILL
LINGER THROUGH 03Z - 06Z TONIGHT. AT THE ELEVATED SITES OF KBGM
AND KITH...IFR CIGS ARE POSSIBLE DURING THIS TIME.
AFTER 06Z GENERALLY VFR IS EXPECTED. DUE TO THE RAINFALL IFR
CONDITIONS CAN`T BE RULED OUT AT KELM DUE TO FOG. CONFIDENCE TOO
LOW TO INCLUDE AT THIS TIME DUE TO BREEZY BOUNDARY LAYER WINDS. SCT
CU AROUND 5KFT WEDNESDAY AND VFR CONDITIONS.
SOUTHEAST WINDS SHIFTING TO THE SOUTHWEST BY 21Z SUSTAINED 10 TO
20 KTS...WITH GUSTS TOWARD 30 KTS. SOUTHWEST WINDS BECOMING WEST
TONIGHT WITH GUSTS TOWARD 20KTS THROUGH 03Z...THEN AROUND 10KTS
OVERNIGHT. NORTHWEST WINDS 10 TO 15 KTS WEDNESDAY.
OUTLOOK...
THU/FRI...VFR EXCEPT IFR FOG AT KELM EACH MORNING FROM 8 TO 14Z.
SAT...MVFR POSSIBLE IN SHOWERS.
SUN...GENERALLY VFR...MVFR POSSIBLE NORTH IN SHOWERS.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...FLASH FLOOD WATCH UNTIL MIDNIGHT EDT TONIGHT FOR PAZ040-044-
047-048-072.
WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR PAZ048.
NY...FLASH FLOOD WATCH UNTIL MIDNIGHT EDT TONIGHT FOR NYZ062.
WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR NYZ046-057-062.
&&
$$
SYNOPSIS...MLJ
NEAR TERM...DJP/MLJ
SHORT TERM...MLJ
LONG TERM...HEDEN/RRM
AVIATION...HEDEN
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
502 PM EDT TUE SEP 18 2012
.SYNOPSIS...
A COLD FRONT WILL SLOWLY PUSH ACROSS THE REGION TONIGHT...WITH
RAIN AND GUSTY WINDS SUBSIDING BY LATER THIS EVENING. HIGH
PRESSURE WILL BUILD IN...BRINGING DRY WEATHER FROM WEDNESDAY
THROUGH FRIDAY.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
5PM...REMOVED WESTERN PORTION OF TORNADO WATCH WHERE RAIN COOLED
AIR AS STABILIZED ATMOSPHERE QUITE A BIT, AND WIND SHEAR HAS
DECREASED. WILL CONTINUE EASTERN PORTION FOR AT LEAST THE NEXT
HOUR.
330 PM UPDATE... WE APPEAR TO BE TRANSITIONING FROM A SVR/WIND
THREAT...TO MORE OF A HVY RAIN THREAT ATTM.
THE BACK EDGE OF THE PRE-FRNTL BAND OF RAIN/EMBEDDED TSRA IS
SLOWLY PUSHING EWD FROM ABT THE I-81 CORRIDOR LATE THIS AFTN. THE
MAIN CONCERN IS TURNING TO A TRAINING SW-NE BATCH OF
+RA/TSRA...EXTENDING FROM S-CNTRL PA UP INTO OUR SERN ZNS...SO FF
WATCHES HAVE BEEN POSTED FOR LUZERNE/LACK/WAYNE/PIKE/SULL CNTYS. SINCE
THE LEADING NRN STREAM WV IS LIFTING OUT TO THE NE THROUGH
ONT...IT WILL LIKELY TAKE THE SECOND WV COMING IN BEHIND IT FROM
WI/UPR MI...TO FINALLY KICK THE HVYR RAIN BAND EWD AFTER 00Z.
AS FOR THE WIND/SVR SITN...STG SYNOPTIC-SCALE WINDS ARE PUSHING
EWD ATTM...AND THE OVERALL WIND THREAT SHOULD BE LWRG WITH TIME
TWDS 00Z. DITTO FOR THE SVR CONVECTIVE SITN.
LTR TNT...DRIER AIR WILL ULTIMATELY PUSH IN FROM THE W...WITH POPS
DIMINISHING BY/AFTER 06Z.
PREV DISC... 1230 PM UPDATE... TOR WATCH #643 ISSUED FOR NE PA
AND SULL CNTY NY...TIL 23Z. THUS...WE`VE ADDED SOME ENHANCED
WORDING FOR THE ISOLD TSRA THIS AREA.
LINEAR FEATURES ARE BCMG MORE PROMINENT ALG THE BACK EDGE OF THE
STEADIER PCPN...AS ALLUDED TO IN PREV DISC. ML CAPES REMAIN FAIRLY
LOW...ON THE ORDER OF 100-200...BUT LOW-LVL SHEAR IS EXTREMELY
IMPRESSIVE (0-1 KM SREL HEL OF 400+). UNLESS MORE DESTAB
OCCURS...DISCRETE CELL DVLPMT IS UNLIKELY...BUT LINES OF
SHRA/EMBEDDED TSRA...WITH LOCALIZED 50+ KT GUSTS ARE PLAUSIBLE.
WE`LL CONTINUE TO MONITOR CLOSELY.
PREV DISC... 10 AM UPDATE... BROAD SWATH OF RA/+RA CONTS TO TRACK
NEWD THROUGH CNY/NE PA ATTM...BEING FUELED BY STG POS THETA-E
ADVCTN ON THE LEADING EDGE OF AN INCRG LOW-LVL JET. WE EXPECT
STEADY RAIN TO PERSIST TIL PERHAPS MID TO LATE AFTN...WHEN THE
BACK EDGE OF THE MAIN PCPN SHIELD...NOW ACRS WRN PA...ATTEMPTS TO
MOVE INTO THE CWA FROM SW TO NE. A BIG QUESTION IS WHAT HAPPENS
AFTER THAT...JUST AHD OF THE COLD FROPA IN THE 21Z-01Z TIME FRAME.
MOST OF THE CONVECTION ALLOWING MODELS (HRRR AND 4 KM WRF...FOR
EXAMPLE) INDICATE THAT SOME SORT OF ENHANCED/CONVECTIVE LN FORMS
ON THE BACK EDGE OF THE STEADIER PCPN AFTER 21Z...TRANSLATING
MAINLY ACRS NE PA AND PTNS OF THE SRN TIER LATE IN THE DAY.
THIS...OF COURSE...WILL DEPEND ON HOW MUCH INSTAB CAN FORM. THE
LATEST RUC SHOWS ML CAPE OF 200-400 THIS TIME FRAME IN OUR SERN
ZNS...WITH THE 12Z NAM COMING IN SHOWING MORE (500-800). GIVEN
EXTENSIVE CLOUD COVER/PCPN FOR SVRL MORE HRS AT LEAST...AND WHAT`S
BEING OBSERVED UPSTREAM ON SPC MESO`S ATTM (ML CAPE OF 100-200 IN
SE PA)...WE`RE INCLINED TO BUY THE MORE CONSERVATIVE RUC. ACRS
ROUGHLY THE SERN HALF OF THE CWA...WE`LL STILL MENTION ISOLD
TSRA...WHILE SHOWING OCNL +RA JUST ABT EVERYWHERE. THE BEST SVR
POTENTIAL APPEARS TO BE JUST SE OF THE CWA...WHERE THE PRIMARY
IMPETUS FOR ANY DISCERNIBLE LN OR DISCRETE CELL FORMATION IS.
KBGM VWP HAS 20-30 KT SRLY FLOW AT 2K FT AGL ATTM...WITH 40-50 KT
AT 3-4K FT AGL. KBGM BASE VEL PRODS ALSO SHOW THE 50-60 KT CORE
MOVG NWD THROUGH ERN PA...AND DESCENDING SOMEWHAT WITH TIME. THE
MOST FAVORABLE TIME FOR CONSISTENTLY STG GRADIENT WIND GUSTS WILL BE
FROM ABT 17-22Z. WIND ADVISORIES REMAIN IN TACT.
UNLESS TRAINING OF HEAVY RAIN BANDS FORM...WE`RE STILL NOT
EXPECTING ANY SIG HYDRO RELATED PROBLEMS...SO NO WATCHES PLANNED
FOR THE TIME BEING.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
340 PM UPDATE... VERY BRIEF DISCN...DUE TO ONGOING SVR WX.
DRY WX STILL ANTICIPATED WED-FRI...OTHER THAN SOME ISOLD -SHRA
EARLY WED...DUE TO A WEAK LAKE RESPONSE.
TEMPS WILL BE UNCHANGED...AS CURRENT MAX/MIN TEMP GRIDS MATCH
BLENDED MOS WELL.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
315 AM UPDATE...CURRENT FORECAST IN GOOD SHAPE, LATEST MODEL RUNS
REMAIN CONSISTENT WITH PREVIOUS CYCLE, NO SIGNIFICANT CHANGES.
PREVIOUS DISC...
FRIDAY THROUGH FRIDAY NIGHT...A DEEP CUT OFF LOW WILL MOVE INTO
THE UPPER MIDWEST DURING THIS TIME. MEANWHILE FARTHER TO THE EAST
IN OUR NECK OF THE WOODS...WE WILL REMAIN IN A DEEP SOUTHWESTERLY
FLOW AHEAD OF THE CUT OFF LOW. INITIALLY THIS WILL BE GREAT NEWS
WITH OUR AREA REMAINING DRY AND EXPERIENCING ABOVE NORMAL TEMPS.
HIGHS FRIDAY SHOULD BE WELL INTO THE 70S...WITH NEAR 80 DEGREE
READINGS ACROSS THE LAKE PLAIN.
SATURDAY AND BEYOND...THE DOWNSIDE TO THE SLOW MOVEMENT OF THE CUT OFF LOW
MENTIONED ABOVE WILL BE AN UNSETTLED WEEKEND. AS THE CUT OFF LOW
MOVES NORTHEAST AND WE BEGIN TO FEEL THE EFFECTS OF THE H5
TROF...RAIN WILL SPREAD OUR WAY LATER SATURDAY INTO SUNDAY. THE
GFS HINTS THAT WE MAY SEE A DRY SLOT LATER SUNDAY...BUT PLENTY OF
UNCERTAINTY EXISTS WITH THE EURO KEEPING US WET. WILL KEEP CHANCE
POPS IN ESPECIALLY ACROSS THE NORTH TO COVER THIS.
&&
.AVIATION /21Z TUESDAY THROUGH SUNDAY/...
OVERVIEW...MVFR CIGS AND VSBYS LIKELY TO PERSIST THROUGH 21Z AS A PRE-FRONTAL
TROF MOVES THROUGH THE TERMINALS AND WE HAVE WIDESPREAD RAIN.
AFTER THIS TIME VSBYS SHOULD IMPROVE AS THE RAIN ENDS...BUT MVFR
CIGS LIKELY TO PERSIST THROUGH EARLY TONIGHT WITH VFR THEREAFTER.
DETAILS...A LINE OF HEAVIER RAIN IS MOVING ACROSS THE TERMINALS NOW...WELL
AHEAD OF A COLD FRONT OVER WESTERN NY. MVFR CIGS AND VSBYS LIKELY
WITH THE RAIN THROUGH 21Z. SOME BRIEF IFR VSBYS POSSIBLE AT
KRME...KBGM...KAVP DUE TO HEAVIER RAIN DURING THIS TIME. IN
ADDITION SOME PERIODS OF VFR LIKELY AT KRME/KSYR/KAVP DUE TO
STRONG DOWNSLOPING WINDS (SOUTHEAST). ONCE THIS LINE MOVES EAST OF
THE AREA AFTER 21Z...VSBYS WILL IMPROVE TO VFR BUT MVFR CIGS WILL
LINGER THROUGH 03Z - 06Z TONIGHT. AT THE ELEVATED SITES OF KBGM
AND KITH...IFR CIGS ARE POSSIBLE DURING THIS TIME.
AFTER 06Z GENERALLY VFR IS EXPECTED. DUE TO THE RAINFALL IFR
CONDITIONS CAN`T BE RULED OUT AT KELM DUE TO FOG. CONFIDENCE TOO
LOW TO INCLUDE AT THIS TIME DUE TO BREEZY BOUNDARY LAYER WINDS. SCT
CU AROUND 5KFT WEDNESDAY AND VFR CONDITIONS.
SOUTHEAST WINDS SHIFTING TO THE SOUTHWEST BY 21Z SUSTAINED 10 TO
20 KTS...WITH GUSTS TOWARD 30 KTS. SOUTHWEST WINDS BECOMING WEST
TONIGHT WITH GUSTS TOWARD 20KTS THROUGH 03Z...THEN AROUND 10KTS
OVERNIGHT. NORTHWEST WINDS 10 TO 15 KTS WEDNESDAY.
OUTLOOK...
THU/FRI...VFR EXCEPT IFR FOG AT KELM EACH MORNING FROM 8 TO 14Z.
SAT...MVFR POSSIBLE IN SHOWERS.
SUN...GENERALLY VFR...MVFR POSSIBLE NORTH IN SHOWERS.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...FLASH FLOOD WATCH UNTIL MIDNIGHT EDT TONIGHT FOR PAZ040-044-
047-048-072.
WIND ADVISORY UNTIL 6 PM EDT THIS EVENING FOR PAZ038>040-043-
044-047-072.
WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR PAZ048.
NY...FLASH FLOOD WATCH UNTIL MIDNIGHT EDT TONIGHT FOR NYZ062.
WIND ADVISORY UNTIL 6 PM EDT THIS EVENING FOR NYZ009-025-036-
037-044-045-055-056.
WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR NYZ046-057-062.
&&
$$
SYNOPSIS...MLJ
NEAR TERM...DJP/MLJ
SHORT TERM...MLJ
LONG TERM...HEDEN/RRM
AVIATION...HEDEN
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
341 PM EDT TUE SEP 18 2012
.SYNOPSIS...
A COLD FRONT WILL SLOWLY PUSH ACROSS THE REGION TONIGHT...WITH
RAIN AND GUSTY WINDS SUBSIDING BY LATER THIS EVENING. HIGH
PRESSURE WILL BUILD IN...BRINGING DRY WEATHER FROM WEDNESDAY
THROUGH FRIDAY.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
330 PM UPDATE... WE APPEAR TO BE TRANSITIONING FROM A SVR/WIND
THREAT...TO MORE OF A HVY RAIN THREAT ATTM.
THE BACK EDGE OF THE PRE-FRNTL BAND OF RAIN/EMBEDDED TSRA IS
SLOWLY PUSHING EWD FROM ABT THE I-81 CORRIDOR LATE THIS AFTN. THE
MAIN CONCERN IS TURNING TO A TRAINING SW-NE BATCH OF
+RA/TSRA...EXTENDING FROM S-CNTRL PA UP INTO OUR SERN ZNS...SO FF
WATCHES HAVE BEEN POSTED FOR LUZERNE/LACK/WAYNE/PIKE/SULL CNTYS. SINCE
THE LEADING NRN STREAM WV IS LIFTING OUT TO THE NE THROUGH
ONT...IT WILL LIKELY TAKE THE SECOND WV COMING IN BEHIND IT FROM
WI/UPR MI...TO FINALLY KICK THE HVYR RAIN BAND EWD AFTER 00Z.
AS FOR THE WIND/SVR SITN...STG SYNOPTIC-SCALE WINDS ARE PUSHING
EWD ATTM...AND THE OVERALL WIND THREAT SHOULD BE LWRG WITH TIME
TWDS 00Z. DITTO FOR THE SVR CONVECTIVE SITN.
LTR TNT...DRIER AIR WILL ULTIMATELY PUSH IN FROM THE W...WITH POPS
DIMINISHING BY/AFTER 06Z.
PREV DISC... 1230 PM UPDATE... TOR WATCH #643 ISSUED FOR NE PA
AND SULL CNTY NY...TIL 23Z. THUS...WE`VE ADDED SOME ENHANCED
WORDING FOR THE ISOLD TSRA THIS AREA.
LINEAR FEATURES ARE BCMG MORE PROMINENT ALG THE BACK EDGE OF THE
STEADIER PCPN...AS ALLUDED TO IN PREV DISC. ML CAPES REMAIN FAIRLY
LOW...ON THE ORDER OF 100-200...BUT LOW-LVL SHEAR IS EXTREMELY
IMPRESSIVE (0-1 KM SREL HEL OF 400+). UNLESS MORE DESTAB
OCCURS...DISCRETE CELL DVLPMT IS UNLIKELY...BUT LINES OF
SHRA/EMBEDDED TSRA...WITH LOCALIZED 50+ KT GUSTS ARE PLAUSIBLE.
WE`LL CONTINUE TO MONITOR CLOSELY.
PREV DISC... 10 AM UPDATE... BROAD SWATH OF RA/+RA CONTS TO TRACK
NEWD THROUGH CNY/NE PA ATTM...BEING FUELED BY STG POS THETA-E
ADVCTN ON THE LEADING EDGE OF AN INCRG LOW-LVL JET. WE EXPECT
STEADY RAIN TO PERSIST TIL PERHAPS MID TO LATE AFTN...WHEN THE
BACK EDGE OF THE MAIN PCPN SHIELD...NOW ACRS WRN PA...ATTEMPTS TO
MOVE INTO THE CWA FROM SW TO NE. A BIG QUESTION IS WHAT HAPPENS
AFTER THAT...JUST AHD OF THE COLD FROPA IN THE 21Z-01Z TIME FRAME.
MOST OF THE CONVECTION ALLOWING MODELS (HRRR AND 4 KM WRF...FOR
EXAMPLE) INDICATE THAT SOME SORT OF ENHANCED/CONVECTIVE LN FORMS
ON THE BACK EDGE OF THE STEADIER PCPN AFTER 21Z...TRANSLATING
MAINLY ACRS NE PA AND PTNS OF THE SRN TIER LATE IN THE DAY.
THIS...OF COURSE...WILL DEPEND ON HOW MUCH INSTAB CAN FORM. THE
LATEST RUC SHOWS ML CAPE OF 200-400 THIS TIME FRAME IN OUR SERN
ZNS...WITH THE 12Z NAM COMING IN SHOWING MORE (500-800). GIVEN
EXTENSIVE CLOUD COVER/PCPN FOR SVRL MORE HRS AT LEAST...AND WHAT`S
BEING OBSERVED UPSTREAM ON SPC MESO`S ATTM (ML CAPE OF 100-200 IN
SE PA)...WE`RE INCLINED TO BUY THE MORE CONSERVATIVE RUC. ACRS
ROUGHLY THE SERN HALF OF THE CWA...WE`LL STILL MENTION ISOLD
TSRA...WHILE SHOWING OCNL +RA JUST ABT EVERYWHERE. THE BEST SVR
POTENTIAL APPEARS TO BE JUST SE OF THE CWA...WHERE THE PRIMARY
IMPETUS FOR ANY DISCERNIBLE LN OR DISCRETE CELL FORMATION IS.
KBGM VWP HAS 20-30 KT SRLY FLOW AT 2K FT AGL ATTM...WITH 40-50 KT
AT 3-4K FT AGL. KBGM BASE VEL PRODS ALSO SHOW THE 50-60 KT CORE
MOVG NWD THROUGH ERN PA...AND DESCENDING SOMEWHAT WITH TIME. THE
MOST FAVORABLE TIME FOR CONSISTENTLY STG GRADIENT WIND GUSTS WILL BE
FROM ABT 17-22Z. WIND ADVISORIES REMAIN IN TACT.
UNLESS TRAINING OF HEAVY RAIN BANDS FORM...WE`RE STILL NOT
EXPECTING ANY SIG HYDRO RELATED PROBLEMS...SO NO WATCHES PLANNED
FOR THE TIME BEING.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
340 PM UPDATE... VERY BRIEF DISCN...DUE TO ONGOING SVR WX.
DRY WX STILL ANTICIPATED WED-FRI...OTHER THAN SOME ISOLD -SHRA
EARLY WED...DUE TO A WEAK LAKE RESPONSE.
TEMPS WILL BE UNCHANGED...AS CURRENT MAX/MIN TEMP GRIDS MATCH
BLENDED MOS WELL.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
315 AM UPDATE...CURRENT FORECAST IN GOOD SHAPE, LATEST MODEL RUNS
REMAIN CONSISTENT WITH PREVIOUS CYCLE, NO SIGNIFICANT CHANGES.
PREVIOUS DISC...
FRIDAY THROUGH FRIDAY NIGHT...A DEEP CUT OFF LOW WILL MOVE INTO
THE UPPER MIDWEST DURING THIS TIME. MEANWHILE FARTHER TO THE EAST
IN OUR NECK OF THE WOODS...WE WILL REMAIN IN A DEEP SOUTHWESTERLY
FLOW AHEAD OF THE CUT OFF LOW. INITIALLY THIS WILL BE GREAT NEWS
WITH OUR AREA REMAINING DRY AND EXPERIENCING ABOVE NORMAL TEMPS.
HIGHS FRIDAY SHOULD BE WELL INTO THE 70S...WITH NEAR 80 DEGREE
READINGS ACROSS THE LAKE PLAIN.
SATURDAY AND BEYOND...THE DOWNSIDE TO THE SLOW MOVEMENT OF THE CUT OFF LOW
MENTIONED ABOVE WILL BE AN UNSETTLED WEEKEND. AS THE CUT OFF LOW
MOVES NORTHEAST AND WE BEGIN TO FEEL THE EFFECTS OF THE H5
TROF...RAIN WILL SPREAD OUR WAY LATER SATURDAY INTO SUNDAY. THE
GFS HINTS THAT WE MAY SEE A DRY SLOT LATER SUNDAY...BUT PLENTY OF
UNCERTAINTY EXISTS WITH THE EURO KEEPING US WET. WILL KEEP CHANCE
POPS IN ESPECIALLY ACROSS THE NORTH TO COVER THIS.
&&
.AVIATION /20Z TUESDAY THROUGH SUNDAY/...
OVERVIEW...MVFR CIGS AND VSBYS LIKELY TO PERSIST THROUGH 21Z AS A PRE-FRONTAL
TROF MOVES THROUGH THE TERMINALS AND WE HAVE WIDESPREAD RAIN.
AFTER THIS TIME VSBYS SHOULD IMPROVE AS THE RAIN ENDS...BUT MVFR
CIGS LIKELY TO PERSIST THROUGH EARLY TONIGHT WITH VFR THEREAFTER.
DETAILS...A LINE OF HEAVIER RAIN IS MOVING ACROSS THE TERMINALS NOW...WELL
AHEAD OF A COLD FRONT OVER WESTERN NY. MVFR CIGS AND VSBYS LIKELY
WITH THE RAIN THROUGH 21Z. SOME BRIEF IFR VSBYS POSSIBLE AT
KRME...KBGM...KAVP DUE TO HEAVIER RAIN DURING THIS TIME. IN
ADDITION SOME PERIODS OF VFR LIKELY AT KRME/KSYR/KAVP DUE TO
STRONG DOWNSLOPING WINDS (SOUTHEAST). ONCE THIS LINE MOVES EAST OF
THE AREA AFTER 21Z...VSBYS WILL IMPROVE TO VFR BUT MVFR CIGS WILL
LINGER THROUGH 03Z - 06Z TONIGHT. AT THE ELEVATED SITES OF KBGM
AND KITH...IFR CIGS ARE POSSIBLE DURING THIS TIME.
AFTER 06Z GENERALLY VFR IS EXPECTED. DUE TO THE RAINFALL IFR
CONDITIONS CAN`T BE RULED OUT AT KELM DUE TO FOG. CONFIDENCE TOO
LOW TO INCLUDE AT THIS TIME DUE TO BREEZY BOUNDARY LAYER WINDS. SCT
CU AROUND 5KFT WEDNESDAY AND VFR CONDITIONS.
SOUTHEAST WINDS SHIFTING TO THE SOUTHWEST BY 21Z SUSTAINED 10 TO
20 KTS...WITH GUSTS TOWARD 30 KTS. SOUTHWEST WINDS BECOMING WEST
TONIGHT WITH GUSTS TOWARD 20KTS THROUGH 03Z...THEN AROUND 10KTS
OVERNIGHT. NORTHWEST WINDS 10 TO 15 KTS WEDNESDAY.
OUTLOOK...
THU/FRI...VFR EXCEPT IFR FOG AT KELM EACH MORNING FROM 8 TO 14Z.
SAT...MVFR POSSIBLE IN SHOWERS.
SUN...GENERALLY VFR...MVFR POSSIBLE NORTH IN SHOWERS.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...FLASH FLOOD WATCH UNTIL MIDNIGHT EDT TONIGHT FOR PAZ040-044-
047-048-072.
WIND ADVISORY UNTIL 6 PM EDT THIS EVENING FOR PAZ038>040-043-
044-047-072.
WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR PAZ048.
NY...FLASH FLOOD WATCH UNTIL MIDNIGHT EDT TONIGHT FOR NYZ062.
WIND ADVISORY UNTIL 6 PM EDT THIS EVENING FOR NYZ009-025-036-
037-044-045-055-056.
WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR NYZ046-057-062.
&&
$$
SYNOPSIS...MLJ
NEAR TERM...MLJ
SHORT TERM...MLJ
LONG TERM...HEDEN/RRM
AVIATION...HEDEN
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
248 PM EDT TUE SEP 18 2012
.SYNOPSIS...
A VIGOROUS LOW PRESSURE SYSTEM WILL BRING STRONG...GUSTY WIND TO
THE AREA LATE THIS MORNING THROUGH THIS EVENING. THIS WILL BE
AHEAD OF A STRONG COLD FRONT THAT WILL ALSO BRING RAIN TO THE
REGION TODAY. THE SYSTEM WILL QUICKLY MOVE OUT OVERNIGHT...AND HIGH
PRESSURE WILL BRING QUIETER CONDITIONS FOR THE REMAINDER OF THE
WORK WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
1230 PM UPDATE... TOR WATCH #643 ISSUED FOR NE PA AND SULL CNTY
NY...TIL 23Z. THUS...WE`VE ADDED SOME ENHANCED WORDING FOR THE
ISOLD TSRA THIS AREA.
LINEAR FEATURES ARE BCMG MORE PROMINENT ALG THE BACK EDGE OF THE
STEADIER PCPN...AS ALLUDED TO IN PREV DISC. ML CAPES REMAIN FAIRLY
LOW...ON THE ORDER OF 100-200...BUT LOW-LVL SHEAR IS EXTREMELY
IMPRESSIVE (0-1 KM SREL HEL OF 400+). UNLESS MORE DESTAB
OCCURS...DISCRETE CELL DVLPMT IS UNLIKELY...BUT LINES OF
SHRA/EMBEDDED TSRA...WITH LOCALIZED 50+ KT GUSTS ARE PLAUSIBLE.
WE`LL CONTINUE TO MONITOR CLOSELY.
PREV DISC... 10 AM UPDATE... BROAD SWATH OF RA/+RA CONTS TO TRACK
NEWD THROUGH CNY/NE PA ATTM...BEING FUELED BY STG POS THETA-E
ADVCTN ON THE LEADING EDGE OF AN INCRG LOW-LVL JET. WE EXPECT
STEADY RAIN TO PERSIST TIL PERHAPS MID TO LATE AFTN...WHEN THE
BACK EDGE OF THE MAIN PCPN SHIELD...NOW ACRS WRN PA...ATTEMPTS TO
MOVE INTO THE CWA FROM SW TO NE. A BIG QUESTION IS WHAT HAPPENS
AFTER THAT...JUST AHD OF THE COLD FROPA IN THE 21Z-01Z TIME FRAME.
MOST OF THE CONVECTION ALLOWING MODELS (HRRR AND 4 KM WRF...FOR
EXAMPLE) INDICATE THAT SOME SORT OF ENHANCED/CONVECTIVE LN FORMS
ON THE BACK EDGE OF THE STEADIER PCPN AFTER 21Z...TRANSLATING
MAINLY ACRS NE PA AND PTNS OF THE SRN TIER LATE IN THE DAY.
THIS...OF COURSE...WILL DEPEND ON HOW MUCH INSTAB CAN FORM. THE
LATEST RUC SHOWS ML CAPE OF 200-400 THIS TIME FRAME IN OUR SERN
ZNS...WITH THE 12Z NAM COMING IN SHOWING MORE (500-800). GIVEN
EXTENSIVE CLOUD COVER/PCPN FOR SVRL MORE HRS AT LEAST...AND WHAT`S
BEING OBSERVED UPSTREAM ON SPC MESO`S ATTM (ML CAPE OF 100-200 IN
SE PA)...WE`RE INCLINED TO BUY THE MORE CONSERVATIVE RUC. ACRS
ROUGHLY THE SERN HALF OF THE CWA...WE`LL STILL MENTION ISOLD
TSRA...WHILE SHOWING OCNL +RA JUST ABT EVERYWHERE. THE BEST SVR
POTENTIAL APPEARS TO BE JUST SE OF THE CWA...WHERE THE PRIMARY
IMPETUS FOR ANY DISCERNIBLE LN OR DISCRETE CELL FORMATION IS.
KBGM VWP HAS 20-30 KT SRLY FLOW AT 2K FT AGL ATTM...WITH 40-50 KT
AT 3-4K FT AGL. KBGM BASE VEL PRODS ALSO SHOW THE 50-60 KT CORE
MOVG NWD THROUGH ERN PA...AND DESCENDING SOMEWHAT WITH TIME. THE
MOST FAVORABLE TIME FOR CONSISTENTLY STG GRADIENT WIND GUSTS WILL BE
FROM ABT 17-22Z. WIND ADVISORIES REMAIN IN TACT.
UNLESS TRAINING OF HEAVY RAIN BANDS FORM...WE`RE STILL NOT
EXPECTING ANY SIG HYDRO RELATED PROBLEMS...SO NO WATCHES PLANNED
FOR THE TIME BEING.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
HIGH PRESSURE WILL BUILD OVER THE AREA. AS IT DOES, SOME COLDER
850MB TEMPS WILL MOVE ACROSS THE GREAT LAKE EARLY WEDNESDAY MORNING.
CURRENTLY THE NAM IS SHOWING TEMPS OF -1C AT 850MB. THE GFS AND
THE ECMWF ARE ONLY 1 OR 2 DEGREES WARMER. GIVEN THIS AND A WEST
NORTHWESTERLY FLOW EARLY WEDNESDAY MORNING, SOME LAKE EFFECT
SHOWERS MAY TRY TO POP UP, MAINLY ACROSS NORTHERN ONONDAGA AND
ONEIDA COUNTIES. THE CHANCE WILL DIMINISH WITH DAYTIME HEATING AND
MIXING WEDNESDAY LATE MORNING. THE REMAINDER OF THE FORECAST
PERIOD WILL BE COOL AND QUIET, WITH HIGH TEMPS IN THE UPPER 50S
AND LOW 60S WEDNESDAY AFTERNOON AND MIDDLE TO UPPER 60S ON
THURSDAY.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
315 AM UPDATE...CURRENT FORECAST IN GOOD SHAPE, LATEST MODEL RUNS
REMAIN CONSISTENT WITH PREVIOUS CYCLE, NO SIGNIFICANT CHANGES.
PREVIOUS DISC...
FRIDAY THROUGH FRIDAY NIGHT...A DEEP CUT OFF LOW WILL MOVE INTO
THE UPPER MIDWEST DURING THIS TIME. MEANWHILE FARTHER TO THE EAST
IN OUR NECK OF THE WOODS...WE WILL REMAIN IN A DEEP SOUTHWESTERLY
FLOW AHEAD OF THE CUT OFF LOW. INITIALLY THIS WILL BE GREAT NEWS
WITH OUR AREA REMAINING DRY AND EXPERIENCING ABOVE NORMAL TEMPS.
HIGHS FRIDAY SHOULD BE WELL INTO THE 70S...WITH NEAR 80 DEGREE
READINGS ACROSS THE LAKE PLAIN.
SATURDAY AND BEYOND...THE DOWNSIDE TO THE SLOW MOVEMENT OF THE CUT OFF LOW
MENTIONED ABOVE WILL BE AN UNSETTLED WEEKEND. AS THE CUT OFF LOW
MOVES NORTHEAST AND WE BEGIN TO FEEL THE EFFECTS OF THE H5
TROF...RAIN WILL SPREAD OUR WAY LATER SATURDAY INTO SUNDAY. THE
GFS HINTS THAT WE MAY SEE A DRY SLOT LATER SUNDAY...BUT PLENTY OF
UNCERTAINTY EXISTS WITH THE EURO KEEPING US WET. WILL KEEP CHANCE
POPS IN ESPECIALLY ACROSS THE NORTH TO COVER THIS.
&&
.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
OVERVIEW...MVFR CIGS AND VSBYS LIKELY TO PERSIST THROUGH 21Z AS A PREFRONTAL
TROF MOVES THROUGH THE TERMINALS AND WE HAVE WIDESPREAD RAIN.
AFTER THIS TIME VSBYS SHOULD IMPROVE AS THE RAIN ENDS...BUT MVFR
CIGS LIKELY TO PERSIST THROUGH EARLY TONIGHT WITH VFR THEREAFTER.
DETAILS...A LINE OF HEAVIER RAIN IS MOVING ACROSS THE TERMINALS NOW...WELL
AHEAD OF A COLD FRONT OVER WESTERN NY. MVFR CIGS AND VSBYS LIKELY
WITH THE RAIN THROUGH 21Z. SOME BRIEF IFR VSBYS POSSIBLE AT
KRME...KBGM...KAVP DUE TO HEAVIER RAIN DURING THIS TIME. IN
ADDITION SOME PERIODS OF VFR LIKELY AT KRME/KSYR/KAVP DUE TO
STRONG DOWNSLOPING WINDS (SOUTHEAST). ONCE THIS LINE MOVES EAST OF
THE AREA AFTER 21Z...VSBYS WILL IMPROVE TO VFR BUT MVFR CIGS WILL
LINGER THROUGH 03Z - 06Z TONIGHT. AT THE ELEVATED SITES OF KBGM
AND KITH...IFR CIGS ARE POSSIBLE DURING THIS TIME.
AFTER 06Z GENERALLY VFR IS EXPECTED. DUE TO THE RAINFALL IFR
CONDITIONS CAN`T BE RULED OUT AT KELM DUE TO FOG. CONFIDENCE TOO
LOW TO INCLUDE AT THIS TIME DUE TO BREEZY BOUNDARY LAYER WINDS. SCT
CU AROUND 5KFT WEDNESDAY AND VFR CONDITIONS.
SOUTHEAST WINDS SHIFTING TO THE SOUTHWEST BY 21Z SUSTAINED 10 TO
20 KTS...WITH GUSTS TOWARD 30 KTS. SOUTHWEST WINDS BECOMING WEST
TONIGHT WITH GUSTS TOWARD 20KTS THROUGH 03Z...THEN AROUND 10KTS
OVERNIGHT. NORTHWEST WINDS 10 TO 15 KTS WEDNESDAY.
OUTLOOK...
THU/FRI...VFR EXCEPT IFR FOG AT KELM EACH MORNING FROM 8 TO 14Z.
SAT...MVFR POSSIBLE IN SHOWERS.
SUN...GENERALLY VFR...MVFR POSSIBLE NORTH IN SHOWERS.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...WIND ADVISORY UNTIL 6 PM EDT THIS EVENING FOR PAZ038>040-043-
044-047-072.
WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR PAZ048.
NY...WIND ADVISORY UNTIL 6 PM EDT THIS EVENING FOR NYZ009-025-036-
037-044-045-055-056.
WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR NYZ046-057-062.
&&
$$
SYNOPSIS...SLI
NEAR TERM...SLI
SHORT TERM...SLI
LONG TERM...HEDEN/RRM
AVIATION...HEDEN
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1239 PM EDT TUE SEP 18 2012
.SYNOPSIS...
A VIGOROUS LOW PRESSURE SYSTEM WILL BRING STRONG...GUSTY WIND TO
THE AREA LATE THIS MORNING THROUGH THIS EVENING. THIS WILL BE
AHEAD OF A STRONG COLD FRONT THAT WILL ALSO BRING RAIN TO THE
REGION TODAY. THE SYSTEM WILL QUICKLY MOVE OUT OVERNIGHT...AND HIGH
PRESSURE WILL BRING QUIETER CONDITIONS FOR THE REMAINDER OF THE
WORK WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
1230 PM UPDATE... TOR WATCH #643 ISSUED FOR NE PA AND SULL CNTY
NY...TIL 23Z. THUS...WE`VE ADDED SOME ENHANCED WORDING FOR THE
ISOLD TSRA THIS AREA.
LINEAR FEATURES ARE BCMG MORE PROMINENT ALG THE BACK EDGE OF THE
STEADIER PCPN...AS ALLUDED TO IN PREV DISC. ML CAPES REMAIN FAIRLY
LOW...ON THE ORDER OF 100-200...BUT LOW-LVL SHEAR IS EXTREMELY
IMPRESSIVE (0-1 KM SREL HEL OF 400+). UNLESS MORE DESTAB
OCCURS...DISCRETE CELL DVLPMT IS UNLIKELY...BUT LINES OF
SHRA/EMBEDDED TSRA...WITH LOCALIZED 50+ KT GUSTS ARE PLAUSIBLE.
WE`LL CONTINUE TO MONITOR CLOSELY.
PREV DISC... 10 AM UPDATE... BROAD SWATH OF RA/+RA CONTS TO TRACK
NEWD THROUGH CNY/NE PA ATTM...BEING FUELED BY STG POS THETA-E
ADVCTN ON THE LEADING EDGE OF AN INCRG LOW-LVL JET. WE EXPECT
STEADY RAIN TO PERSIST TIL PERHAPS MID TO LATE AFTN...WHEN THE
BACK EDGE OF THE MAIN PCPN SHIELD...NOW ACRS WRN PA...ATTEMPTS TO
MOVE INTO THE CWA FROM SW TO NE. A BIG QUESTION IS WHAT HAPPENS
AFTER THAT...JUST AHD OF THE COLD FROPA IN THE 21Z-01Z TIME FRAME.
MOST OF THE CONVECTION ALLOWING MODELS (HRRR AND 4 KM WRF...FOR
EXAMPLE) INDICATE THAT SOME SORT OF ENHANCED/CONVECTIVE LN FORMS
ON THE BACK EDGE OF THE STEADIER PCPN AFTER 21Z...TRANSLATING
MAINLY ACRS NE PA AND PTNS OF THE SRN TIER LATE IN THE DAY.
THIS...OF COURSE...WILL DEPEND ON HOW MUCH INSTAB CAN FORM. THE
LATEST RUC SHOWS ML CAPE OF 200-400 THIS TIME FRAME IN OUR SERN
ZNS...WITH THE 12Z NAM COMING IN SHOWING MORE (500-800). GIVEN
EXTENSIVE CLOUD COVER/PCPN FOR SVRL MORE HRS AT LEAST...AND WHAT`S
BEING OBSERVED UPSTREAM ON SPC MESO`S ATTM (ML CAPE OF 100-200 IN
SE PA)...WE`RE INCLINED TO BUY THE MORE CONSERVATIVE RUC. ACRS
ROUGHLY THE SERN HALF OF THE CWA...WE`LL STILL MENTION ISOLD
TSRA...WHILE SHOWING OCNL +RA JUST ABT EVERYWHERE. THE BEST SVR
POTENTIAL APPEARS TO BE JUST SE OF THE CWA...WHERE THE PRIMARY
IMPETUS FOR ANY DISCERNIBLE LN OR DISCRETE CELL FORMATION IS.
KBGM VWP HAS 20-30 KT SRLY FLOW AT 2K FT AGL ATTM...WITH 40-50 KT
AT 3-4K FT AGL. KBGM BASE VEL PRODS ALSO SHOW THE 50-60 KT CORE
MOVG NWD THROUGH ERN PA...AND DESCENDING SOMEWHAT WITH TIME. THE
MOST FAVORABLE TIME FOR CONSISTENTLY STG GRADIENT WIND GUSTS WILL BE
FROM ABT 17-22Z. WIND ADVISORIES REMAIN IN TACT.
UNLESS TRAINING OF HEAVY RAIN BANDS FORM...WE`RE STILL NOT
EXPECTING ANY SIG HYDRO RELATED PROBLEMS...SO NO WATCHES PLANNED
FOR THE TIME BEING.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
HIGH PRESSURE WILL BUILD OVER THE AREA. AS IT DOES, SOME COLDER
850MB TEMPS WILL MOVE ACROSS THE GREAT LAKE EARLY WEDNESDAY MORNING.
CURRENTLY THE NAM IS SHOWING TEMPS OF -1C AT 850MB. THE GFS AND
THE ECMWF ARE ONLY 1 OR 2 DEGREES WARMER. GIVEN THIS AND A WEST
NORTHWESTERLY FLOW EARLY WEDNESDAY MORNING, SOME LAKE EFFECT
SHOWERS MAY TRY TO POP UP, MAINLY ACROSS NORTHERN ONONDAGA AND
ONEIDA COUNTIES. THE CHANCE WILL DIMINISH WITH DAYTIME HEATING AND
MIXING WEDNESDAY LATE MORNING. THE REMAINDER OF THE FORECAST
PERIOD WILL BE COOL AND QUIET, WITH HIGH TEMPS IN THE UPPER 50S
AND LOW 60S WEDNESDAY AFTERNOON AND MIDDLE TO UPPER 60S ON
THURSDAY.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
315 AM UPDATE...CURRENT FORECAST IN GOOD SHAPE, LATEST MODEL RUNS
REMAIN CONSISTENT WITH PREVIOUS CYCLE, NO SIGNIFICANT CHANGES.
PREVIOUS DISC...
FRIDAY THROUGH FRIDAY NIGHT...A DEEP CUT OFF LOW WILL MOVE INTO
THE UPPER MIDWEST DURING THIS TIME. MEANWHILE FARTHER TO THE EAST
IN OUR NECK OF THE WOODS...WE WILL REMAIN IN A DEEP SOUTHWESTERLY
FLOW AHEAD OF THE CUT OFF LOW. INITIALLY THIS WILL BE GREAT NEWS
WITH OUR AREA REMAINING DRY AND EXPERIENCING ABOVE NORMAL TEMPS.
HIGHS FRIDAY SHOULD BE WELL INTO THE 70S...WITH NEAR 80 DEGREE
READINGS ACROSS THE LAKE PLAIN.
SATURDAY AND BEYOND...THE DOWNSIDE TO THE SLOW MOVEMENT OF THE CUT OFF LOW
MENTIONED ABOVE WILL BE AN UNSETTLED WEEKEND. AS THE CUT OFF LOW
MOVES NORTHEAST AND WE BEGIN TO FEEL THE EFFECTS OF THE H5
TROF...RAIN WILL SPREAD OUR WAY LATER SATURDAY INTO SUNDAY. THE
GFS HINTS THAT WE MAY SEE A DRY SLOT LATER SUNDAY...BUT PLENTY OF
UNCERTAINTY EXISTS WITH THE EURO KEEPING US WET. WILL KEEP CHANCE
POPS IN ESPECIALLY ACROSS THE NORTH TO COVER THIS.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
AN INTENSIFYING LOW PRES SYSTEM IN THE OH VALLEY WITH PRODUCE
MODERATE RAIN ACROSS THE TERMINALS THROUGH TODAY. WIDESPREAD LOW
MVFR CONDITIONS ARE EXPECTED WITH IFR LIKELY FOR MUCH OF THE DAY
AT KITH/KBGM. STRONG FLOW SHOULD PREVENT WIDESPREAD IFR CIGS. A
STRONG COLD FRONT WILL CROSS THE REGION BETWEEN 23Z-02Z, WITH
PRECIP ENDING AROUND THREE HOURS AFTER FROPA BUT IN GENERAL MVFR
CIGS WILL PERSIST.
WINDS S/SE AT 10 KTS THEN INCREASING BY MID MORNING FROM THE SOUTH
AT 10-15 KNOTS WITH GUSTS 25-30 KNOTS BECOMING SOUTHWEST DURING
THE AFTERNOON THEN WESTERLY AFTER FROPA AROUND 10 KNOTS WITH GUSTS
AROUND 20 KNOTS.
AT KAVP/KELM LOW LEVEL WIND SHEAR WILL EXISTS THROUGH MID MORNING
WITH LIGHT WINDS AT THE SFC AND GUSTY SOUTHERLY WINDS AT 2K FT.
OUTLOOK...
WED...VFR.
THU/FRI...VFR EXCEPT IFR FOG AT KELM EACH MORNING FROM 8 TO 14Z.
SAT...MVFR POSSIBLE IN SHOWERS.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...WIND ADVISORY UNTIL 6 PM EDT THIS EVENING FOR PAZ038>040-043-
044-047-072.
WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR PAZ048.
NY...WIND ADVISORY UNTIL 6 PM EDT THIS EVENING FOR NYZ009-025-036-
037-044-045-055-056.
WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR NYZ046-057-062.
&&
$$
SYNOPSIS...SLI/MLJ
NEAR TERM...SLI/MLJ
SHORT TERM...SLI
LONG TERM...HEDEN/RRM
AVIATION...RRM
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1033 AM EDT TUE SEP 18 2012
.SYNOPSIS...
A VIGOROUS LOW PRESSURE SYSTEM WILL BRING STRONG...GUSTY WIND TO
THE AREA LATE THIS MORNING THROUGH THIS EVENING. THIS WILL BE
AHEAD OF A STRONG COLD FRONT THAT WILL ALSO BRING RAIN TO THE
REGION TODAY. THE SYSTEM WILL QUICKLY MOVE OUT OVERNIGHT...AND HIGH
PRESSURE WILL BRING QUIETER CONDITIONS FOR THE REMAINDER OF THE
WORK WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
10 AM UPDATE... BROAD SWATH OF RA/+RA CONTS TO TRACK NEWD THROUGH
CNY/NE PA ATTM...BEING FUELED BY STG POS THETA-E ADVCTN ON THE
LEADING EDGE OF AN INCRG LOW-LVL JET. WE EXPECT STEADY RAIN TO
PERSIST TIL PERHAPS MID TO LATE AFTN...WHEN THE BACK EDGE OF THE
MAIN PCPN SHIELD...NOW ACRS WRN PA...ATTEMPTS TO MOVE INTO THE CWA
FROM SW TO NE. A BIG QUESTION IS WHAT HAPPENS AFTER THAT...JUST AHD
OF THE COLD FROPA IN THE 21Z-01Z TIME FRAME.
MOST OF THE CONVECTION ALLOWING MODELS (HRRR AND 4 KM WRF...FOR
EXAMPLE) INDICATE THAT SOME SORT OF ENHANCED/CONVECTIVE LN FORMS
ON THE BACK EDGE OF THE STEADIER PCPN AFTER 21Z...TRANSLATING
MAINLY ACRS NE PA AND PTNS OF THE SRN TIER LATE IN THE DAY.
THIS...OF COURSE...WILL DEPEND ON HOW MUCH INSTAB CAN FORM. THE
LATEST RUC SHOWS ML CAPE OF 200-400 THIS TIME FRAME IN OUR SERN
ZNS...WITH THE 12Z NAM COMING IN SHOWING MORE (500-800). GIVEN
EXTENSIVE CLOUD COVER/PCPN FOR SVRL MORE HRS AT LEAST...AND WHAT`S
BEING OBSERVED UPSTREAM ON SPC MESO`S ATTM (ML CAPE OF 100-200 IN
SE PA)...WE`RE INCLINED TO BUY THE MORE CONSERVATIVE RUC. ACRS
ROUGHLY THE SERN HALF OF THE CWA...WE`LL STILL MENTION ISOLD
TSRA...WHILE SHOWING OCNL +RA JUST ABT EVERYWHERE. THE BEST SVR
POTENTIAL APPEARS TO BE JUST SE OF THE CWA...WHERE THE PRIMARY
IMPETUS FOR ANY DISCERNIBLE LN OR DISCRETE CELL FORMATION IS.
KBGM VWP HAS 20-30 KT SRLY FLOW AT 2K FT AGL ATTM...WITH 40-50 KT
AT 3-4K FT AGL. KBGM BASE VEL PRODS ALSO SHOW THE 50-60 KT CORE
MOVG NWD THROUGH ERN PA...AND DESCENDING SOMEWHAT WITH TIME. THE
MOST FAVORABLE TIME FOR CONSISTENTLY STG GRADIENT WIND GUSTS WILL BE
FROM ABT 17-22Z. WIND ADVISORIES REMAIN IN TACT.
UNLESS TRAINING OF HEAVY RAIN BANDS FORM...WE`RE STILL NOT
EXPECTING ANY SIG HYDRO RELATED PROBLEMS...SO NO WATCHES PLANNED
FOR THE TIME BEING.
PREV DISC... THE BIG STORY OF THE DAY LOOKS TO BE THE STRONG
WINDS EXPECTED AHEAD OF A COLD FRONT. CURRENTLY, AN ELONGATED SFC
LOW IS SITUATED FROM AROUND NEW ORLEANS ALL THE WAY UP TO THE
NORTH OF THE GREAT LAKES. THIS LOW WILL TIGHTEN UP AND DEVELOP
FURTHER OVER THE EASTERN GREAT LAKES THIS MORNING. WITH A
TIGHTENING PRESSURE GRADIENT, ORIENTED EAST TO WEST, WINDS WILL
INCREASE THIS MORNING OUT OF THE SOUTH TO SOUTH EAST. GIVEN THAT A
LLJ IS ALSO EXPECTED BETWEEN 925MB AND 850MB AT AROUND 60 KTS THIS
AFTERNOON, WINDS SHOULD BE ABLE TO INCREASE TO AROUND 20 TO 25 KTS
SUSTAINED, ESPECIALLY IN HIGHER TERRAIN. SOME OF THE HIGH WINDS
ALOFT SHOULD ALSO MIX DOWN, ALLOWING FREQUENT GUSTS OF 35 TO 40
KTS. THERE IS A SMALL POTENTIAL FOR THE HIGHER ELEVATIONS OF THE
CATSKILLS TO SEE INFREQUENT GUSTS OF OVER 45 KTS. MODELS ARE
INDICATING THAT THE FRONT AND LLJ WILL QUICKLY PUSH EASTWARD LATE
THIS AFTERNOON AND MAY BE TOTALLY OUT OF THE CWA BY 00Z. IT WILL
LINGER THE LONGEST IN THE EASTERN ZONES, HENCE THE ADVISORY
LASTING A FEW HOURS LONGER.
ON TOP OF THE STRONG WINDS TODAY, RAIN WILL BE ANOTHER FACTOR.
MODELS ARE INDICATING PWATS OF NEARLY TWO INCHES TODAY. ALSO, CURRENT
HPC PREDICTIONS SHOW AROUND 2 INCHES ARE POSSIBLE ACROSS THE CWA
TODAY. CAN NOT DISAGREE WITH THIS ASSESSMENT. WITH CURRENT MONTHLY
RAINFALL TOTALS BEING BELOW NORMAL AND LOW RIVER LEVELS, NOT
EXPECTING ANY IMPACTS ON A LARGE SCALE. THERE MAY BE SOME MINOR
FLASH FLOODING AT HEADWATERS AND AREAS THAT NORMALLY REACT QUICKLY
TO ANY RAIN. ALSO, LOW LYING AREAS AND URBAN AREAS WITH POOR
DRAINAGE COULD SEE SOME PONDING OF WATER.
AS FAR AS CONVECTIVE POTENTIAL TODAY. WHILE SPC DOES HAVE MUCH OF
THE AREA IN A SLIGHT RISK, THE FEELING IS THAT IT IS UNLIKELY IN
THE BGM CWA AS THE LLJ WILL LIKELY BE TO STRONG FOR ANY
SIGNIFICANT CELLS TO DEVELOP BEFORE BEING SHEARED APART. ALSO,
CAPS VALUES LOOK TO STRUGGLE TO GET ABOVE 300 JOULES THIS
AFTERNOON AS RAIN SHOWERS AND CLOUD COVER HAVE ALREADY BEGAN TO
OVERSPREAD THE REGION, WHICH WILL LIMIT INSOLATION TODAY. LAPSE
RATES WILL ALSO GREATLY LIMIT ANY CONVECTIVE POTENTIAL AS THE
STRUGGLE TO REACH 6 TODAY. EVEN SO, HAVE KEPT A MENTION OF AN
ISOLATED, GENERAL THUNDERSTORM OVER THE SOUTHERN ZONES THIS
AFTERNOON AS AN ISOLATED CELL COULD DEVELOP A CAUSE A FEW STRIKES
BEFORE BEING TORN APART.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
HIGH PRESSURE WILL BUILD OVER THE AREA. AS IT DOES, SOME COLDER
850MB TEMPS WILL MOVE ACROSS THE GREAT LAKE EARLY WEDNESDAY MORNING.
CURRENTLY THE NAM IS SHOWING TEMPS OF -1C AT 850MB. THE GFS AND
THE ECMWF ARE ONLY 1 OR 2 DEGREES WARMER. GIVEN THIS AND A WEST
NORTHWESTERLY FLOW EARLY WEDNESDAY MORNING, SOME LAKE EFFECT
SHOWERS MAY TRY TO POP UP, MAINLY ACROSS NORTHERN ONONDAGA AND
ONEIDA COUNTIES. THE CHANCE WILL DIMINISH WITH DAYTIME HEATING AND
MIXING WEDNESDAY LATE MORNING. THE REMAINDER OF THE FORECAST
PERIOD WILL BE COOL AND QUIET, WITH HIGH TEMPS IN THE UPPER 50S
AND LOW 60S WEDNESDAY AFTERNOON AND MIDDLE TO UPPER 60S ON
THURSDAY.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
315 AM UPDATE...CURRENT FORECAST IN GOOD SHAPE, LATEST MODEL RUNS
REMAIN CONSISTENT WITH PREVIOUS CYCLE, NO SIGNIFICANT CHANGES.
PREVIOUS DISC...
FRIDAY THROUGH FRIDAY NIGHT...A DEEP CUT OFF LOW WILL MOVE INTO
THE UPPER MIDWEST DURING THIS TIME. MEANWHILE FARTHER TO THE EAST
IN OUR NECK OF THE WOODS...WE WILL REMAIN IN A DEEP SOUTHWESTERLY
FLOW AHEAD OF THE CUT OFF LOW. INITIALLY THIS WILL BE GREAT NEWS
WITH OUR AREA REMAINING DRY AND EXPERIENCING ABOVE NORMAL TEMPS.
HIGHS FRIDAY SHOULD BE WELL INTO THE 70S...WITH NEAR 80 DEGREE
READINGS ACROSS THE LAKE PLAIN.
SATURDAY AND BEYOND...THE DOWNSIDE TO THE SLOW MOVEMENT OF THE CUT OFF LOW
MENTIONED ABOVE WILL BE AN UNSETTLED WEEKEND. AS THE CUT OFF LOW
MOVES NORTHEAST AND WE BEGIN TO FEEL THE EFFECTS OF THE H5
TROF...RAIN WILL SPREAD OUR WAY LATER SATURDAY INTO SUNDAY. THE
GFS HINTS THAT WE MAY SEE A DRY SLOT LATER SUNDAY...BUT PLENTY OF
UNCERTAINTY EXISTS WITH THE EURO KEEPING US WET. WILL KEEP CHANCE
POPS IN ESPECIALLY ACROSS THE NORTH TO COVER THIS.
&&
.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
AN INTENSIFYING LOW PRES SYSTEM IN THE OH VALLEY WITH PRODUCE
MODERATE RAIN ACROSS THE TERMINALS THROUGH TODAY. WIDESPREAD LOW
MVFR CONDITIONS ARE EXPECTED WITH IFR LIKELY FOR MUCH OF THE DAY
AT KITH/KBGM. STRONG FLOW SHOULD PREVENT WIDESPREAD IFR CIGS. A
STRONG COLD FRONT WILL CROSS THE REGION BETWEEN 23Z-02Z, WITH
PRECIP ENDING AROUND THREE HOURS AFTER FROPA BUT IN GENERAL MVFR
CIGS WILL PERSIST.
WINDS S/SE AT 10 KTS THEN INCREASING BY MID MORNING FROM THE SOUTH
AT 10-15 KNOTS WITH GUSTS 25-30 KNOTS BECOMING SOUTHWEST DURING
THE AFTERNOON THEN WESTERLY AFTER FROPA AROUND 10 KNOTS WITH GUSTS
AROUND 20 KNOTS.
AT KAVP/KELM LOW LEVEL WIND SHEAR WILL EXISTS THROUGH MID MORNING
WITH LIGHT WINDS AT THE SFC AND GUSTY SOUTHERLY WINDS AT 2K FT.
OUTLOOK...
WED...VFR.
THU/FRI...VFR EXCEPT IFR FOG AT KELM EACH MORNING FROM 8 TO 14Z.
SAT...MVFR POSSIBLE IN SHOWERS.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...WIND ADVISORY UNTIL 6 PM EDT THIS EVENING FOR PAZ038>040-043-
044-047-072.
WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR PAZ048.
NY...WIND ADVISORY UNTIL 6 PM EDT THIS EVENING FOR NYZ009-025-036-
037-044-045-055-056.
WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR NYZ046-057-062.
&&
$$
SYNOPSIS...SLI
NEAR TERM...SLI
SHORT TERM...SLI
LONG TERM...HEDEN/RRM
AVIATION...RRM
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1218 PM CDT TUE SEP 18 2012
.DISCUSSION...
SEE AVIATION DISCUSSION BELOW.
&&
.AVIATION...
VFR CONDITIONS WILL PREVAIL OVER THE NEXT 24 HOURS. THE SCATTERED
CLOUD COVER WILL MOVE OFF AND DISSIPATE BY 20Z. WINDS WILL REMAIN
GENERALLY LESS THAN 11 KTS WITH VARIABLE WINDS OVERNIGHT AT
BBD...JCT...AND SOA.
&&
.PREV DISCUSSION... /ISSUED 958 AM CDT TUE SEP 18 2012/
UPDATE...
UPDATED THE POPS AND WEATHER GRIDS.
DISCUSSION...
UPDATED TO FORECAST TO REMOVE THE POPS AND WEATHER FOR THE BIG
COUNTRY.
PREV DISCUSSION... /ISSUED 633 AM CDT TUE SEP 18 2012/
DISCUSSION...
/SEE BELOW FOR AVIATION DISCUSSION/
AVIATION...
THUNDERSTORMS WILL MOVE THROUGH KABI THROUGH 14Z. STORMS HAVE
WEAKENED...BUT MAY STILL BE CAPABLE OF WINDS OF 35 KTS AND LOWERED
VISIBILITIES OF 1 TO 3 MILES. SCATTERED LIGHT SHOWERS AND PERHAPS A
THUNDERSTORM MAY ALSO AFFECT KSJT THROUGH 14Z...BUT WILL ONLY PUT
VCTS IN THE TAF AS MOST OF THE STORMS WILL PASS NORTH. OTHERWISE
NORTH WINDS INCREASE TO 10 KT AS A COLD FRONT MOVES THROUGH THIS
MORNING.
PREV DISCUSSION... /ISSUED 404 AM CDT TUE SEP 18 2012/
SHORT TERM...
CONVECTIVE COMPLEX IN ASSOCIATION WITH AN UPPER SHORTWAVE AND COLD
FRONT WAS MOVING INTO THE BIG COUNTRY AT 3 AM. THERE WERE SOME
STRONG STORMS ASSOCIATED WITH IT...WHICH MAY BE PRODUCING SOME SMALL
HAIL.
COLD FRONT AND UPPER SHORTWAVE MOVE SE ACROSS THE BIG COUNTRY AND
HEARTLAND THIS MORNING. THIS AREA WILL ALSO BE IN AN AREA OF UPPER
LEVEL DIVERGENCE ASSOCIATED WITH THE LEFT EXIT REGION OF A 100 KT
JET AT 200 MB...WITH THE AXIS OF THE JET ALONG I-10. MORNING STORM
ACTIVITY WAS MORE WIDESPREAD THAN THE NAM OR GFS MODELS THIS
MORNING. RUC MODEL HOWEVER DOES HAVE A BETTER HANDLE ON STORM
PLACEMENT AND AREAL EXTENT...THOUGH EVEN THE RUC RAPIDLY WEAKENS
CONVECTIVE ACTIVITY BY 9 AM AND CONFINES RAINFALL TO THE BIG COUNTRY.
DID KEEP A SLIGHT CHANCE OF STORMS IN FARTHER WEST IN THE CONCHO
VALLEY HOWEVER...WITH A VORT MAX INDICATED IN WATER VAPOR
LOOP...EMBEDDED IN THE WESTERN SIDE OF THE UPPER SHORTWAVE IN NEW
MEXICO. WENT SLIGHTLY COOLER THAN GFS MOS TODAY WITH COLD ADVECTION
AND MID/UPPER LEVEL CLOUDS ASSOCIATED WITH SHORTWAVE. KEPT
THUNDERSTORM CHANCES ONLY FOR THIS MORNING...WITH SUBSIDENCE BEHIND
EXITING SHORTWAVE BY NOON.
LONG TERM...
A DRY FORECAST IN STORE FOR WEST CENTRAL TEXAS IN THE LONG TERM.
WEDNESDAY THROUGH FRIDAY...UPPER LEVEL RIDGE WILL REMAIN CENTERED
OVER THE WESTERN US. ANOMALOUSLY DEEP UPPER TROUGH WILL BE MAINTAINED
ACROSS THE NORTHERN GREAT LAKES AND UPPER MIDWEST. FOR WEST CENTRAL
TEXAS...TEMPERATURES WILL BE WARMER ON WEDNESDAY AS LIGHT SOUTHERLY
FLOW DEVELOPS WITH AMPLE SUNSHINE. PER THE 850 MB THERMAL PATTERN...
EXPECT DAYTIME TEMPERATURES TO BE A FEW DEGREES ABOVE NORMAL WITH
AFTERNOON HIGHS IN THE UPPER 80S TO LOWER 90S THURSDAY AND FRIDAY.
SOME MODEL DISAGREEMENT IS SHOWN WITH PROGRESS AND STRENGTH OF A
COLD FRONT FOR NEXT WEEKEND. AS A STRONG UPPER LOW DEVELOPS SOUTH
TOWARD THE NORTHERN GREAT LAKES...A DISTURBANCE IS PROGGED TO
PINWHEEL AROUND ITS SOUTHWESTERN PERIPHERY ON SATURDAY. THE 00Z
ECMWF HAS A STRONGER ASSOCIATED COLD FRONT DROPPING SOUTH ACROSS
WEST CENTRAL TEXAS LATE SATURDAY NIGHT AND SUNDAY MORNING...WITH A
1030 MB SURFACE HIGH DROPPING SOUTH ACROSS THE NORTHERN AND CENTRAL
PLAINS BEHIND THE FRONT. THE 00Z GFS HAS A CONSIDERABLY WEAKER
COLD FRONT MOVING SOUTH INTO THE BIG COUNTRY ON SATURDAY AFTERNOON...
AND BRINGS ONLY A GLANCING SHOT OF SLIGHTLY COOLER AIR INTO WEST
CENTRAL TEXAS. THE GFS ENSEMBLE SHOWS CONSIDERABLE SPREAD IN
SURFACE WINDS FOR NEXT WEEKEND. TIMING AND STRENGTH OF COLD FRONT
WILL LIKELY DEPEND ON EVOLUTION OF THE UPPER LEVEL FLOW PATTERN
ACROSS THE GREAT LAKES AND MIDWEST. GIVEN THE UNCERTAINTY...LITTLE
CHANGE WAS MADE TO THE WIND FIELD FOR NEXT WEEKEND. EITHER WAY
WITH THE MODELS...MOISTURE LOOKS TOO LIMITED IN OUR AREA TO
SUPPORT RAIN CHANCES WITH THE COLD FRONT.
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 79 57 86 63 89 / 10 0 0 5 5
SAN ANGELO 82 58 88 62 90 / 20 0 0 0 5
JUNCTION 84 57 87 57 89 / 20 0 0 0 0
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
REIMER
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
1210 PM CDT TUE SEP 18 2012
.AVIATION...
MVFR CEILINGS WILL CONTINUE TO LIFT AND SCATTER THROUGH EARLY
AFTERNOON AS DRIER AIR FILTERS IN BEHIND A COLD FRONT. EXPECT VFR
CONDITIONS AT ALL TAF SITES THIS AFTERNOON THROUGH WEDNESDAY
MORNING WITH A MOSTLY CLEAR SKY. A NORTH WIND WILL PREVAIL BETWEEN
10 AND 15 KNOTS THIS AFTERNOON AND SHOULD DECREASE BELOW 12 KNOTS
AFTER SUNSET. THE WIND WILL BECOME LIGHT AND VARIABLE OVERNIGHT
THEN TURN TO THE SOUTHEAST/SOUTH WEDNESDAY MORNING IN RESPONSE TO
DEVELOPING SURFACE LOW PRESSURE ACROSS THE CENTRAL AND SOUTHERN
HIGH PLAINS.
79
&&
.UPDATE...
FOR THE MIDDAY UPDATE...WE HAVE MOVED THE THUNDER POTENTIAL FARTHER
SOUTH TO THE FAR SOUTHERN COUNTIES WHILE ISOLATED SHOWERS REMAIN
POSSIBLE SOUTH OF I-20. THE SHORTWAVE CURRENTLY MOVING ACROSS THE
TEXAS HILL COUNTRY AS IT PREPARES TO DROP INTO THE BASE OF THE
LONG WAVE UPPER TROUGH ALIGNED NORTH-SOUTH ALONG THE MISSISSIPPI
RIVER. DRY LOW LEVEL AIR AND SURFACE DEWPOINTS IN THE MID 40S AS
CROSSED THE RED RIVER AND WILL CONTINUE TO PUSH SOUTH DURING THE
DAY. EXPECT THE CLEARING TO MOVE SOUTH OF I-20 JUST AFTER MIDDAY
THEN THROUGH THE SOUTHERN COUNTIES BY 5 OR 6 PM. LITTLE CHANGE WAS
MADE TO THE EXTEND FORECAST FOR NOW. 75
&&
.PREV DISCUSSION... /ISSUED 241 AM CDT TUE SEP 18 2012/
UPPER LOW THAT AFFECTED NORTH TEXAS THIS PAST WEEKEND WAS MOVING
INTO THE LOWER MISSISSIPPI VALLEY THIS MORNING. ANOTHER VIGOROUS
SHORTWAVE CAN BE SEEN WITHIN NORTHWEST FLOW ALOFT MOVING OVER THE
TEXAS PANHANDLE EARLY THIS MORNING. MEANWHILE...A COLD FRONT WAS
MOVING ACROSS THE RED RIVER AND AS OF 2 AM WAS ALONG A LAKE TEXOMA...
BOWIE...SEYMOUR LINE. THE FRONT WAS EXPECTED TO REACH THE I-20
BETWEEN 4 AND 5 AM...OR BEFORE SUNRISE...THEN MOVE THROUGH CENTRAL
TEXAS BY MID-LATE MORNING. BRISK AND COOLER CONDITIONS ARE
EXPECTED BEHIND THE FRONT TODAY WITH NORTH WINDS 10 TO 20 MPH
EXPECTED BEHIND THE FRONT. CAA IS IMPRESSIVE AS WELL... THOUGH
LAGGING ABOUT 100 MILES BEHIND THE FRONT. THE CAA COMBINED WITH
WITH MID AND HIGH CLOUDINESS THE FIRST HALF OF THE DAY WILL KEEP
HIGH TEMPERATURES THIS AFTERNOON DOWN IN THE MID AND UPPER 70S
NORTH WITH LOWER 80S SOUTH OF I-20.
IN ADDITION...MID LEVEL MOISTURE WILL BE SUBSTANTIAL ENOUGH FOR A
FEW THUNDERSTORMS ACROSS OUR WESTERN CWA LATER THIS MORNING PER
WRF AND HRRR MODELS. THE BEST STRONGEST FORCING WILL TRACK ACROSS
THE SOUTHWEST COUNTIES LATER THIS MORNING. ELSEWHERE...FORCING IS
NOT EXPECTED TO BE AS STRONG WITH ISOLATED SHOWERS EXPECTED. THE
ELEVATED AND HIGH-BASED NATURE OF CONVECTION WILL RESULT IN ONLY
LIGHT RAINFALL AMOUNTS...LIKELY LESS THAN QUARTER OF AN INCH.
HOWEVER...STEEP MID LEVEL LAPSE RATES AT/ABOVE 7 DEG C/KM AND
STRONG FORCING ALOFT MAY RESULT IN A STRONG STORM OR TWO CONTAINING
FREQUENT LIGHTNING AND POSSIBLY SMALL HAIL ACROSS THE WESTERN
COUNTIES LATER THIS MORNING. BEST LIFT SHIFTS SOUTH OF I-20 WITH
THE FRONT PUSHING TO THE TEXAS COAST THIS AFTERNOON...AS THIS
SYSTEM WILL BE MUCH MORE PROGRESSIVE THAN THE PREVIOUS WEEKEND
SYSTEM WAS. WILL CONTINUE A SLIGHT CHANCE ACROSS THE CENTRAL TEXAS
COUNTIES THIS AFTERNOON...BEFORE BOTH THE SHORTWAVE AND FRONT MOVE
AWAY FROM THE AREA BY EVENING.
HIGH PRESSURE WILL SETTLE IN TONIGHT WITH LIGHT WINDS AND MOSTLY
CLEAR SKIES. EXPECT A GOOD RADIATIONAL COOLING SET UP WITH LOWS
FALLING FALLING INTO THE 50S...THOUGH SOME ISOLATED READINGS IN
THE UPPER 40S CANNOT BE RULED OUT ACROSS PROTECTED RURAL AREAS.
HIGHS WILL REBOUND INTO THE UPPER 70S ACROSS THE EAST TO THE MID
80S IN THE WEST WEDNESDAY. THE UPPER RIDGE WILL CONTINUE EXPANDING
OVERHEAD THURSDAY AND FRIDAY WITH A MODERATION OF TEMPERATURES.
HIGHS BY FRIDAY WILL SOAR TO NEAR 90 DEGREES...BUT THE HUMIDITY
SHOULD BE RELATIVELY LOW. THE GREAT LAKES VORTEX WILL DEEPEN BY
LATE FRIDAY INTO THE WEEKEND AND WILL DRAG ANOTHER COLD FRONT INTO
NORTH TEXAS SATURDAY OR POSSIBLY SATURDAY NIGHT DEPENDING ON
WHETHER YOU BUY THE SLOWER ECMWF OR FASTER GEM/GFS MODELS. HAVE
TAKEN A MEAN ON THE TIMING AND WARMED HIGHS BACK UP SLIGHTLY ON
SATURDAY. WITH MOISTURE AVAILABILITY NOT LOOKING VERY GOOD WITH
THIS FRONT...HAVE DECIDED TO LEAVE THE FORECAST NEXT WEEKEND DRY.
05/
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 78 57 83 62 86 / 10 0 0 5 5
WACO, TX 80 56 85 59 86 / 20 0 0 0 5
PARIS, TX 75 52 80 55 85 / 10 0 0 5 5
DENTON, TX 78 53 84 60 88 / 10 0 0 5 5
MCKINNEY, TX 77 53 82 57 88 / 10 0 0 5 5
DALLAS, TX 79 59 83 64 87 / 10 0 0 5 5
TERRELL, TX 78 54 82 57 86 / 10 0 0 5 5
CORSICANA, TX 80 55 83 57 86 / 10 5 0 0 5
TEMPLE, TX 81 56 84 58 86 / 20 5 0 0 5
MINERAL WELLS, TX 76 55 86 60 88 / 20 0 0 5 5
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
79/75
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1129 AM CDT TUE SEP 18 2012
.UPDATE...
FOR THE MIDDAY UPDATE...WE HAVE MOVED THE THUNDER POTENTIAL FARTHER
SOUTH TO THE FAR SOUTHERN COUNTIES WHILE ISOLATED SHOWERS REMAIN
POSSIBLE SOUTH OF I-20. THE SHORTWAVE CURRENTLY MOVING ACROSS THE
TEXAS HILL COUNTRY AS IT PREPARES TO DROP INTO THE BASE OF THE
LONG WAVE UPPER TROUGH ALIGNED NORTH-SOUTH ALONG THE MISSISSIPPI
RIVER. DRY LOW LEVEL AIR AND SURFACE DEWPOINTS IN THE MID 40S AS
CROSSED THE RED RIVER AND WILL CONTINUE TO PUSH SOUTH DURING THE
DAY. EXPECT THE CLEARING TO MOVE SOUTH OF I-20 JUST AFTER MIDDAY
THEN THROUGH THE SOUTHERN COUNTIES BY 5 OR 6 PM. LITTLE CHANGE WAS
MADE TO THE EXTEND FORECAST FOR NOW. 75
&&
.AVIATION...
EXPECT VFR WITH NORTH FLOW THRU TODAY. FRONT SHOULD BE THROUGH
METROPLEX TAF SITES NEAR 12Z...SO WILL START TAFS WITH POST
FRONTAL NORTH WINDS. MVFR STRATUS IN OKLAHOMA WELL BEHIND FRONT
WILL REACH METROPLEX AROUND 16-17Z...AND WITH MORNING WARMING
SHOULD REMAIN SCT. WILL HAVE TO KEEP AN EYE ON IT BUT SHOULD IT GO
BKN IT MAY BE ABOVE 030 BY THEN. WINDS WILL TURN BACK SOUTH LATE
IN THE EVENING. 84
&&
.PREV DISCUSSION... /ISSUED 241 AM CDT TUE SEP 18 2012/
UPPER LOW THAT AFFECTED NORTH TEXAS THIS PAST WEEKEND WAS MOVING
INTO THE LOWER MISSISSIPPI VALLEY THIS MORNING. ANOTHER VIGOROUS
SHORTWAVE CAN BE SEEN WITHIN NORTHWEST FLOW ALOFT MOVING OVER THE
TEXAS PANHANDLE EARLY THIS MORNING. MEANWHILE...A COLD FRONT WAS
MOVING ACROSS THE RED RIVER AND AS OF 2 AM WAS ALONG A LAKE TEXOMA...
BOWIE...SEYMOUR LINE. THE FRONT WAS EXPECTED TO REACH THE I-20
BETWEEN 4 AND 5 AM...OR BEFORE SUNRISE...THEN MOVE THROUGH CENTRAL
TEXAS BY MID-LATE MORNING. BRISK AND COOLER CONDITIONS ARE
EXPECTED BEHIND THE FRONT TODAY WITH NORTH WINDS 10 TO 20 MPH
EXPECTED BEHIND THE FRONT. CAA IS IMPRESSIVE AS WELL... THOUGH
LAGGING ABOUT 100 MILES BEHIND THE FRONT. THE CAA COMBINED WITH
WITH MID AND HIGH CLOUDINESS THE FIRST HALF OF THE DAY WILL KEEP
HIGH TEMPERATURES THIS AFTERNOON DOWN IN THE MID AND UPPER 70S
NORTH WITH LOWER 80S SOUTH OF I-20.
IN ADDITION...MID LEVEL MOISTURE WILL BE SUBSTANTIAL ENOUGH FOR A
FEW THUNDERSTORMS ACROSS OUR WESTERN CWA LATER THIS MORNING PER
WRF AND HRRR MODELS. THE BEST STRONGEST FORCING WILL TRACK ACROSS
THE SOUTHWEST COUNTIES LATER THIS MORNING. ELSEWHERE...FORCING IS
NOT EXPECTED TO BE AS STRONG WITH ISOLATED SHOWERS EXPECTED. THE
ELEVATED AND HIGH-BASED NATURE OF CONVECTION WILL RESULT IN ONLY
LIGHT RAINFALL AMOUNTS...LIKELY LESS THAN QUARTER OF AN INCH.
HOWEVER...STEEP MID LEVEL LAPSE RATES AT/ABOVE 7 DEG C/KM AND
STRONG FORCING ALOFT MAY RESULT IN A STRONG STORM OR TWO CONTAINING
FREQUENT LIGHTNING AND POSSIBLY SMALL HAIL ACROSS THE WESTERN
COUNTIES LATER THIS MORNING. BEST LIFT SHIFTS SOUTH OF I-20 WITH
THE FRONT PUSHING TO THE TEXAS COAST THIS AFTERNOON...AS THIS
SYSTEM WILL BE MUCH MORE PROGRESSIVE THAN THE PREVIOUS WEEKEND
SYSTEM WAS. WILL CONTINUE A SLIGHT CHANCE ACROSS THE CENTRAL TEXAS
COUNTIES THIS AFTERNOON...BEFORE BOTH THE SHORTWAVE AND FRONT MOVE
AWAY FROM THE AREA BY EVENING.
HIGH PRESSURE WILL SETTLE IN TONIGHT WITH LIGHT WINDS AND MOSTLY
CLEAR SKIES. EXPECT A GOOD RADIATIONAL COOLING SET UP WITH LOWS
FALLING FALLING INTO THE 50S...THOUGH SOME ISOLATED READINGS IN
THE UPPER 40S CANNOT BE RULED OUT ACROSS PROTECTED RURAL AREAS.
HIGHS WILL REBOUND INTO THE UPPER 70S ACROSS THE EAST TO THE MID
80S IN THE WEST WEDNESDAY. THE UPPER RIDGE WILL CONTINUE EXPANDING
OVERHEAD THURSDAY AND FRIDAY WITH A MODERATION OF TEMPERATURES.
HIGHS BY FRIDAY WILL SOAR TO NEAR 90 DEGREES...BUT THE HUMIDITY
SHOULD BE RELATIVELY LOW. THE GREAT LAKES VORTEX WILL DEEPEN BY
LATE FRIDAY INTO THE WEEKEND AND WILL DRAG ANOTHER COLD FRONT INTO
NORTH TEXAS SATURDAY OR POSSIBLY SATURDAY NIGHT DEPENDING ON
WHETHER YOU BUY THE SLOWER ECMWF OR FASTER GEM/GFS MODELS. HAVE
TAKEN A MEAN ON THE TIMING AND WARMED HIGHS BACK UP SLIGHTLY ON
SATURDAY. WITH MOISTURE AVAILABILITY NOT LOOKING VERY GOOD WITH
THIS FRONT...HAVE DECIDED TO LEAVE THE FORECAST NEXT WEEKEND DRY.
05/
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 78 57 83 62 86 / 10 0 0 5 5
WACO, TX 80 56 85 59 86 / 20 0 0 0 5
PARIS, TX 75 52 80 55 85 / 10 0 0 5 5
DENTON, TX 78 53 84 60 88 / 10 0 0 5 5
MCKINNEY, TX 77 53 82 57 88 / 10 0 0 5 5
DALLAS, TX 79 59 83 64 87 / 10 0 0 5 5
TERRELL, TX 78 54 82 57 86 / 10 0 0 5 5
CORSICANA, TX 80 55 83 57 86 / 10 5 0 0 5
TEMPLE, TX 81 56 84 58 86 / 20 5 0 0 5
MINERAL WELLS, TX 76 55 86 60 88 / 20 0 0 5 5
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
/75
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
958 AM CDT TUE SEP 18 2012
.UPDATE...
UPDATED THE POPS AND WEATHER GRIDS.
&&
.DISCUSSION...
UPDATED TO FORECAST TO REMOVE THE POPS AND WEATHER FOR THE BIG
COUNTRY.
&&
.PREV DISCUSSION... /ISSUED 633 AM CDT TUE SEP 18 2012/
DISCUSSION...
/SEE BELOW FOR AVIATION DISCUSSION/
AVIATION...
THUNDERSTORMS WILL MOVE THROUGH KABI THROUGH 14Z. STORMS HAVE
WEAKENED...BUT MAY STILL BE CAPABLE OF WINDS OF 35 KTS AND LOWERED
VISIBILITIES OF 1 TO 3 MILES. SCATTERED LIGHT SHOWERS AND PERHAPS A
THUNDERSTORM MAY ALSO AFFECT KSJT THROUGH 14Z...BUT WILL ONLY PUT
VCTS IN THE TAF AS MOST OF THE STORMS WILL PASS NORTH. OTHERWISE
NORTH WINDS INCREASE TO 10 KT AS A COLD FRONT MOVES THROUGH THIS
MORNING.
PREV DISCUSSION... /ISSUED 404 AM CDT TUE SEP 18 2012/
SHORT TERM...
CONVECTIVE COMPLEX IN ASSOCIATION WITH AN UPPER SHORTWAVE AND COLD
FRONT WAS MOVING INTO THE BIG COUNTRY AT 3 AM. THERE WERE SOME
STRONG STORMS ASSOCIATED WITH IT...WHICH MAY BE PRODUCING SOME SMALL
HAIL.
COLD FRONT AND UPPER SHORTWAVE MOVE SE ACROSS THE BIG COUNTRY AND
HEARTLAND THIS MORNING. THIS AREA WILL ALSO BE IN AN AREA OF UPPER
LEVEL DIVERGENCE ASSOCIATED WITH THE LEFT EXIT REGION OF A 100 KT
JET AT 200 MB...WITH THE AXIS OF THE JET ALONG I-10. MORNING STORM
ACTIVITY WAS MORE WIDESPREAD THAN THE NAM OR GFS MODELS THIS
MORNING. RUC MODEL HOWEVER DOES HAVE A BETTER HANDLE ON STORM
PLACEMENT AND AREAL EXTENT...THOUGH EVEN THE RUC RAPIDLY WEAKENS
CONVECTIVE ACTIVITY BY 9 AM AND CONFINES RAINFALL TO THE BIG COUNTRY.
DID KEEP A SLIGHT CHANCE OF STORMS IN FARTHER WEST IN THE CONCHO
VALLEY HOWEVER...WITH A VORT MAX INDICATED IN WATER VAPOR
LOOP...EMBEDDED IN THE WESTERN SIDE OF THE UPPER SHORTWAVE IN NEW
MEXICO. WENT SLIGHTLY COOLER THAN GFS MOS TODAY WITH COLD ADVECTION
AND MID/UPPER LEVEL CLOUDS ASSOCIATED WITH SHORTWAVE. KEPT
THUNDERSTORM CHANCES ONLY FOR THIS MORNING...WITH SUBSIDENCE BEHIND
EXITING SHORTWAVE BY NOON.
LONG TERM...
A DRY FORECAST IN STORE FOR WEST CENTRAL TEXAS IN THE LONG TERM.
WEDNESDAY THROUGH FRIDAY...UPPER LEVEL RIDGE WILL REMAIN CENTERED
OVER THE WESTERN US. ANOMALOUSLY DEEP UPPER TROUGH WILL BE MAINTAINED
ACROSS THE NORTHERN GREAT LAKES AND UPPER MIDWEST. FOR WEST CENTRAL
TEXAS...TEMPERATURES WILL BE WARMER ON WEDNESDAY AS LIGHT SOUTHERLY
FLOW DEVELOPS WITH AMPLE SUNSHINE. PER THE 850 MB THERMAL PATTERN...
EXPECT DAYTIME TEMPERATURES TO BE A FEW DEGREES ABOVE NORMAL WITH
AFTERNOON HIGHS IN THE UPPER 80S TO LOWER 90S THURSDAY AND FRIDAY.
SOME MODEL DISAGREEMENT IS SHOWN WITH PROGRESS AND STRENGTH OF A
COLD FRONT FOR NEXT WEEKEND. AS A STRONG UPPER LOW DEVELOPS SOUTH
TOWARD THE NORTHERN GREAT LAKES...A DISTURBANCE IS PROGGED TO
PINWHEEL AROUND ITS SOUTHWESTERN PERIPHERY ON SATURDAY. THE 00Z
ECMWF HAS A STRONGER ASSOCIATED COLD FRONT DROPPING SOUTH ACROSS
WEST CENTRAL TEXAS LATE SATURDAY NIGHT AND SUNDAY MORNING...WITH A
1030 MB SURFACE HIGH DROPPING SOUTH ACROSS THE NORTHERN AND CENTRAL
PLAINS BEHIND THE FRONT. THE 00Z GFS HAS A CONSIDERABLY WEAKER
COLD FRONT MOVING SOUTH INTO THE BIG COUNTRY ON SATURDAY AFTERNOON...
AND BRINGS ONLY A GLANCING SHOT OF SLIGHTLY COOLER AIR INTO WEST
CENTRAL TEXAS. THE GFS ENSEMBLE SHOWS CONSIDERABLE SPREAD IN
SURFACE WINDS FOR NEXT WEEKEND. TIMING AND STRENGTH OF COLD FRONT
WILL LIKELY DEPEND ON EVOLUTION OF THE UPPER LEVEL FLOW PATTERN
ACROSS THE GREAT LAKES AND MIDWEST. GIVEN THE UNCERTAINTY...LITTLE
CHANGE WAS MADE TO THE WIND FIELD FOR NEXT WEEKEND. EITHER WAY
WITH THE MODELS...MOISTURE LOOKS TOO LIMITED IN OUR AREA TO
SUPPORT RAIN CHANCES WITH THE COLD FRONT.
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 79 56 86 63 89 / 10 0 0 5 5
SAN ANGELO 82 57 88 62 90 / 20 0 0 5 5
JUNCTION 84 55 87 57 89 / 20 0 0 5 5
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
REIMER
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
633 AM CDT TUE SEP 18 2012
.DISCUSSION...
/SEE BELOW FOR AVIATION DISCUSSION/
&&
.AVIATION...
THUNDERSTORMS WILL MOVE THROUGH KABI THROUGH 14Z. STORMS HAVE
WEAKENED...BUT MAY STILL BE CAPABLE OF WINDS OF 35 KTS AND LOWERED
VISIBILITIES OF 1 TO 3 MILES. SCATTERED LIGHT SHOWERS AND PERHAPS A
THUNDERSTORM MAY ALSO AFFECT KSJT THROUGH 14Z...BUT WILL ONLY PUT
VCTS IN THE TAF AS MOST OF THE STORMS WILL PASS NORTH. OTHERWISE
NORTH WINDS INCREASE TO 10 KT AS A COLD FRONT MOVES THROUGH THIS
MORNING.
&&
.PREV DISCUSSION... /ISSUED 404 AM CDT TUE SEP 18 2012/
SHORT TERM...
CONVECTIVE COMPLEX IN ASSOCIATION WITH AN UPPER SHORTWAVE AND COLD
FRONT WAS MOVING INTO THE BIG COUNTRY AT 3 AM. THERE WERE SOME
STRONG STORMS ASSOCIATED WITH IT...WHICH MAY BE PRODUCING SOME SMALL
HAIL.
COLD FRONT AND UPPER SHORTWAVE MOVE SE ACROSS THE BIG COUNTRY AND
HEARTLAND THIS MORNING. THIS AREA WILL ALSO BE IN AN AREA OF UPPER
LEVEL DIVERGENCE ASSOCIATED WITH THE LEFT EXIT REGION OF A 100 KT
JET AT 200 MB...WITH THE AXIS OF THE JET ALONG I-10. MORNING STORM
ACTIVITY WAS MORE WIDESPREAD THAN THE NAM OR GFS MODELS THIS
MORNING. RUC MODEL HOWEVER DOES HAVE A BETTER HANDLE ON STORM
PLACEMENT AND AREAL EXTENT...THOUGH EVEN THE RUC RAPIDLY WEAKENS
CONVECTIVE ACTIVITY BY 9 AM AND CONFINES RAINFALL TO THE BIG COUNTRY.
DID KEEP A SLIGHT CHANCE OF STORMS IN FARTHER WEST IN THE CONCHO
VALLEY HOWEVER...WITH A VORT MAX INDICATED IN WATER VAPOR
LOOP...EMBEDDED IN THE WESTERN SIDE OF THE UPPER SHORTWAVE IN NEW
MEXICO. WENT SLIGHTLY COOLER THAN GFS MOS TODAY WITH COLD ADVECTION
AND MID/UPPER LEVEL CLOUDS ASSOCIATED WITH SHORTWAVE. KEPT
THUNDERSTORM CHANCES ONLY FOR THIS MORNING...WITH SUBSIDENCE BEHIND
EXITING SHORTWAVE BY NOON.
LONG TERM...
A DRY FORECAST IN STORE FOR WEST CENTRAL TEXAS IN THE LONG TERM.
WEDNESDAY THROUGH FRIDAY...UPPER LEVEL RIDGE WILL REMAIN CENTERED
OVER THE WESTERN US. ANOMALOUSLY DEEP UPPER TROUGH WILL BE MAINTAINED
ACROSS THE NORTHERN GREAT LAKES AND UPPER MIDWEST. FOR WEST CENTRAL
TEXAS...TEMPERATURES WILL BE WARMER ON WEDNESDAY AS LIGHT SOUTHERLY
FLOW DEVELOPS WITH AMPLE SUNSHINE. PER THE 850 MB THERMAL PATTERN...
EXPECT DAYTIME TEMPERATURES TO BE A FEW DEGREES ABOVE NORMAL WITH
AFTERNOON HIGHS IN THE UPPER 80S TO LOWER 90S THURSDAY AND FRIDAY.
SOME MODEL DISAGREEMENT IS SHOWN WITH PROGRESS AND STRENGTH OF A
COLD FRONT FOR NEXT WEEKEND. AS A STRONG UPPER LOW DEVELOPS SOUTH
TOWARD THE NORTHERN GREAT LAKES...A DISTURBANCE IS PROGGED TO
PINWHEEL AROUND ITS SOUTHWESTERN PERIPHERY ON SATURDAY. THE 00Z
ECMWF HAS A STRONGER ASSOCIATED COLD FRONT DROPPING SOUTH ACROSS
WEST CENTRAL TEXAS LATE SATURDAY NIGHT AND SUNDAY MORNING...WITH A
1030 MB SURFACE HIGH DROPPING SOUTH ACROSS THE NORTHERN AND CENTRAL
PLAINS BEHIND THE FRONT. THE 00Z GFS HAS A CONSIDERABLY WEAKER
COLD FRONT MOVING SOUTH INTO THE BIG COUNTRY ON SATURDAY AFTERNOON...
AND BRINGS ONLY A GLANCING SHOT OF SLIGHTLY COOLER AIR INTO WEST
CENTRAL TEXAS. THE GFS ENSEMBLE SHOWS CONSIDERABLE SPREAD IN
SURFACE WINDS FOR NEXT WEEKEND. TIMING AND STRENGTH OF COLD FRONT
WILL LIKELY DEPEND ON EVOLUTION OF THE UPPER LEVEL FLOW PATTERN
ACROSS THE GREAT LAKES AND MIDWEST. GIVEN THE UNCERTAINTY...LITTLE
CHANGE WAS MADE TO THE WIND FIELD FOR NEXT WEEKEND. EITHER WAY
WITH THE MODELS...MOISTURE LOOKS TOO LIMITED IN OUR AREA TO
SUPPORT RAIN CHANCES WITH THE COLD FRONT.
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 79 56 86 63 89 / 30 0 0 5 5
SAN ANGELO 82 57 88 62 90 / 20 0 0 5 5
JUNCTION 84 55 87 57 89 / 10 0 0 5 5
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
99/99/04
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
611 AM CDT TUE SEP 18 2012
.AVIATION...
EXPECT VFR WITH NORTH FLOW THRU TODAY. FRONT SHOULD BE THROUGH
METROPLEX TAF SITES NEAR 12Z...SO WILL START TAFS WITH POST
FRONTAL NORTH WINDS. MVFR STRATUS IN OKLAHOMA WELL BEHIND FRONT
WILL REACH METROPLEX AROUND 16-17Z...AND WITH MORNING WARMING
SHOULD REMAIN SCT. WILL HAVE TO KEEP AN EYE ON IT BUT SHOULD IT GO
BKN IT MAY BE ABOVE 030 BY THEN. WINDS WILL TURN BACK SOUTH LATE
IN THE EVENING. 84
&&
.PREV DISCUSSION... /ISSUED 241 AM CDT TUE SEP 18 2012/
UPPER LOW THAT AFFECTED NORTH TEXAS THIS PAST WEEKEND WAS MOVING
INTO THE LOWER MISSISSIPPI VALLEY THIS MORNING. ANOTHER VIGOROUS
SHORTWAVE CAN BE SEEN WITHIN NORTHWEST FLOW ALOFT MOVING OVER THE
TEXAS PANHANDLE EARLY THIS MORNING. MEANWHILE...A COLD FRONT WAS
MOVING ACROSS THE RED RIVER AND AS OF 2 AM WAS ALONG A LAKE TEXOMA...
BOWIE...SEYMOUR LINE. THE FRONT WAS EXPECTED TO REACH THE I-20
BETWEEN 4 AND 5 AM...OR BEFORE SUNRISE...THEN MOVE THROUGH CENTRAL
TEXAS BY MID-LATE MORNING. BRISK AND COOLER CONDITIONS ARE
EXPECTED BEHIND THE FRONT TODAY WITH NORTH WINDS 10 TO 20 MPH
EXPECTED BEHIND THE FRONT. CAA IS IMPRESSIVE AS WELL... THOUGH
LAGGING ABOUT 100 MILES BEHIND THE FRONT. THE CAA COMBINED WITH
WITH MID AND HIGH CLOUDINESS THE FIRST HALF OF THE DAY WILL KEEP
HIGH TEMPERATURES THIS AFTERNOON DOWN IN THE MID AND UPPER 70S
NORTH WITH LOWER 80S SOUTH OF I-20.
IN ADDITION...MID LEVEL MOISTURE WILL BE SUBSTANTIAL ENOUGH FOR A
FEW THUNDERSTORMS ACROSS OUR WESTERN CWA LATER THIS MORNING PER
WRF AND HRRR MODELS. THE BEST STRONGEST FORCING WILL TRACK ACROSS
THE SOUTHWEST COUNTIES LATER THIS MORNING. ELSEWHERE...FORCING IS
NOT EXPECTED TO BE AS STRONG WITH ISOLATED SHOWERS EXPECTED. THE
ELEVATED AND HIGH-BASED NATURE OF CONVECTION WILL RESULT IN ONLY
LIGHT RAINFALL AMOUNTS...LIKELY LESS THAN QUARTER OF AN INCH.
HOWEVER...STEEP MID LEVEL LAPSE RATES AT/ABOVE 7 DEG C/KM AND
STRONG FORCING ALOFT MAY RESULT IN A STRONG STORM OR TWO CONTAINING
FREQUENT LIGHTNING AND POSSIBLY SMALL HAIL ACROSS THE WESTERN
COUNTIES LATER THIS MORNING. BEST LIFT SHIFTS SOUTH OF I-20 WITH
THE FRONT PUSHING TO THE TEXAS COAST THIS AFTERNOON...AS THIS
SYSTEM WILL BE MUCH MORE PROGRESSIVE THAN THE PREVIOUS WEEKEND
SYSTEM WAS. WILL CONTINUE A SLIGHT CHANCE ACROSS THE CENTRAL TEXAS
COUNTIES THIS AFTERNOON...BEFORE BOTH THE SHORTWAVE AND FRONT MOVE
AWAY FROM THE AREA BY EVENING.
HIGH PRESSURE WILL SETTLE IN TONIGHT WITH LIGHT WINDS AND MOSTLY
CLEAR SKIES. EXPECT A GOOD RADIATIONAL COOLING SET UP WITH LOWS
FALLING FALLING INTO THE 50S...THOUGH SOME ISOLATED READINGS IN
THE UPPER 40S CANNOT BE RULED OUT ACROSS PROTECTED RURAL AREAS.
HIGHS WILL REBOUND INTO THE UPPER 70S ACROSS THE EAST TO THE MID
80S IN THE WEST WEDNESDAY. THE UPPER RIDGE WILL CONTINUE EXPANDING
OVERHEAD THURSDAY AND FRIDAY WITH A MODERATION OF TEMPERATURES.
HIGHS BY FRIDAY WILL SOAR TO NEAR 90 DEGREES...BUT THE HUMIDITY
SHOULD BE RELATIVELY LOW. THE GREAT LAKES VORTEX WILL DEEPEN BY
LATE FRIDAY INTO THE WEEKEND AND WILL DRAG ANOTHER COLD FRONT INTO
NORTH TEXAS SATURDAY OR POSSIBLY SATURDAY NIGHT DEPENDING ON
WHETHER YOU BUY THE SLOWER ECMWF OR FASTER GEM/GFS MODELS. HAVE
TAKEN A MEAN ON THE TIMING AND WARMED HIGHS BACK UP SLIGHTLY ON
SATURDAY. WITH MOISTURE AVAILABILITY NOT LOOKING VERY GOOD WITH
THIS FRONT...HAVE DECIDED TO LEAVE THE FORECAST NEXT WEEKEND DRY.
05/
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 78 57 81 62 85 / 10 0 0 5 5
WACO, TX 80 56 83 59 85 / 20 0 0 0 5
PARIS, TX 75 52 78 55 84 / 10 0 0 5 5
DENTON, TX 78 53 82 60 87 / 10 0 0 5 5
MCKINNEY, TX 77 53 80 57 87 / 10 0 0 5 5
DALLAS, TX 79 59 81 64 86 / 10 0 0 5 5
TERRELL, TX 78 54 80 57 85 / 10 0 0 5 5
CORSICANA, TX 80 55 81 57 85 / 10 5 0 0 5
TEMPLE, TX 81 56 82 58 85 / 20 5 0 0 5
MINERAL WELLS, TX 76 55 84 60 87 / 20 0 0 5 5
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
/
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
404 AM CDT TUE SEP 18 2012
.SHORT TERM...
CONVECTIVE COMPLEX IN ASSOCIATION WITH AN UPPER SHORTWAVE AND COLD
FRONT WAS MOVING INTO THE BIG COUNTRY AT 3 AM. THERE WERE SOME
STRONG STORMS ASSOCIATED WITH IT...WHICH MAY BE PRODUCING SOME SMALL
HAIL.
COLD FRONT AND UPPER SHORTWAVE MOVE SE ACROSS THE BIG COUNTRY AND
HEARTLAND THIS MORNING. THIS AREA WILL ALSO BE IN AN AREA OF UPPER
LEVEL DIVERGENCE ASSOCIATED WITH THE LEFT EXIT REGION OF A 100 KT
JET AT 200 MB...WITH THE AXIS OF THE JET ALONG I-10. MORNING STORM
ACTIVITY WAS MORE WIDESPREAD THAN THE NAM OR GFS MODELS THIS
MORNING. RUC MODEL HOWEVER DOES HAVE A BETTER HANDLE ON STORM
PLACEMENT AND AREAL EXTENT...THOUGH EVEN THE RUC RAPIDLY WEAKENS
CONVECTIVE ACTIVITY BY 9 AM AND CONFINES RAINFALL TO THE BIG COUNTRY.
DID KEEP A SLIGHT CHANCE OF STORMS IN FARTHER WEST IN THE CONCHO
VALLEY HOWEVER...WITH A VORT MAX INDICATED IN WATER VAPOR
LOOP...EMBEDDED IN THE WESTERN SIDE OF THE UPPER SHORTWAVE IN NEW
MEXICO. WENT SLIGHTLY COOLER THAN GFS MOS TODAY WITH COLD ADVECTION
AND MID/UPPER LEVEL CLOUDS ASSOCIATED WITH SHORTWAVE. KEPT
THUNDERSTORM CHANCES ONLY FOR THIS MORNING...WITH SUBSIDENCE BEHIND
EXITING SHORTWAVE BY NOON.
.LONG TERM...
A DRY FORECAST IN STORE FOR WEST CENTRAL TEXAS IN THE LONG TERM.
WEDNESDAY THROUGH FRIDAY...UPPER LEVEL RIDGE WILL REMAIN CENTERED
OVER THE WESTERN US. ANOMALOUSLY DEEP UPPER TROUGH WILL BE MAINTAINED
ACROSS THE NORTHERN GREAT LAKES AND UPPER MIDWEST. FOR WEST CENTRAL
TEXAS...TEMPERATURES WILL BE WARMER ON WEDNESDAY AS LIGHT SOUTHERLY
FLOW DEVELOPS WITH AMPLE SUNSHINE. PER THE 850 MB THERMAL PATTERN...
EXPECT DAYTIME TEMPERATURES TO BE A FEW DEGREES ABOVE NORMAL WITH
AFTERNOON HIGHS IN THE UPPER 80S TO LOWER 90S THURSDAY AND FRIDAY.
SOME MODEL DISAGREEMENT IS SHOWN WITH PROGRESS AND STRENGTH OF A
COLD FRONT FOR NEXT WEEKEND. AS A STRONG UPPER LOW DEVELOPS SOUTH
TOWARD THE NORTHERN GREAT LAKES...A DISTURBANCE IS PROGGED TO
PINWHEEL AROUND ITS SOUTHWESTERN PERIPHERY ON SATURDAY. THE 00Z
ECMWF HAS A STRONGER ASSOCIATED COLD FRONT DROPPING SOUTH ACROSS
WEST CENTRAL TEXAS LATE SATURDAY NIGHT AND SUNDAY MORNING...WITH A
1030 MB SURFACE HIGH DROPPING SOUTH ACROSS THE NORTHERN AND CENTRAL
PLAINS BEHIND THE FRONT. THE 00Z GFS HAS A CONSIDERABLY WEAKER
COLD FRONT MOVING SOUTH INTO THE BIG COUNTRY ON SATURDAY AFTERNOON...
AND BRINGS ONLY A GLANCING SHOT OF SLIGHTLY COOLER AIR INTO WEST
CENTRAL TEXAS. THE GFS ENSEMBLE SHOWS CONSIDERABLE SPREAD IN
SURFACE WINDS FOR NEXT WEEKEND. TIMING AND STRENGTH OF COLD FRONT
WILL LIKELY DEPEND ON EVOLUTION OF THE UPPER LEVEL FLOW PATTERN
ACROSS THE GREAT LAKES AND MIDWEST. GIVEN THE UNCERTAINTY...LITTLE
CHANGE WAS MADE TO THE WIND FIELD FOR NEXT WEEKEND. EITHER WAY
WITH THE MODELS...MOISTURE LOOKS TOO LIMITED IN OUR AREA TO
SUPPORT RAIN CHANCES WITH THE COLD FRONT.
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 79 56 86 63 89 / 30 0 0 5 5
SAN ANGELO 82 57 88 62 90 / 20 0 0 5 5
JUNCTION 84 55 87 57 89 / 10 0 0 5 5
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
04/19
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
241 AM CDT TUE SEP 18 2012
.DISCUSSION...
UPPER LOW THAT AFFECTED NORTH TEXAS THIS PAST WEEKEND WAS MOVING
INTO THE LOWER MISSISSIPPI VALLEY THIS MORNING. ANOTHER VIGOROUS
SHORTWAVE CAN BE SEEN WITHIN NORTHWEST FLOW ALOFT MOVING OVER THE
TEXAS PANHANDLE EARLY THIS MORNING. MEANWHILE...A COLD FRONT WAS
MOVING ACROSS THE RED RIVER AND AS OF 2 AM WAS ALONG A LAKE TEXOMA...
BOWIE...SEYMOUR LINE. THE FRONT WAS EXPECTED TO REACH THE I-20
BETWEEN 4 AND 5 AM...OR BEFORE SUNRISE...THEN MOVE THROUGH CENTRAL
TEXAS BY MID-LATE MORNING. BRISK AND COOLER CONDITIONS ARE
EXPECTED BEHIND THE FRONT TODAY WITH NORTH WINDS 10 TO 20 MPH
EXPECTED BEHIND THE FRONT. CAA IS IMPRESSIVE AS WELL... THOUGH
LAGGING ABOUT 100 MILES BEHIND THE FRONT. THE CAA COMBINED WITH
WITH MID AND HIGH CLOUDINESS THE FIRST HALF OF THE DAY WILL KEEP
HIGH TEMPERATURES THIS AFTERNOON DOWN IN THE MID AND UPPER 70S
NORTH WITH LOWER 80S SOUTH OF I-20.
IN ADDITION...MID LEVEL MOISTURE WILL BE SUBSTANTIAL ENOUGH FOR A
FEW THUNDERSTORMS ACROSS OUR WESTERN CWA LATER THIS MORNING PER
WRF AND HRRR MODELS. THE BEST STRONGEST FORCING WILL TRACK ACROSS
THE SOUTHWEST COUNTIES LATER THIS MORNING. ELSEWHERE...FORCING IS
NOT EXPECTED TO BE AS STRONG WITH ISOLATED SHOWERS EXPECTED. THE
ELEVATED AND HIGH-BASED NATURE OF CONVECTION WILL RESULT IN ONLY
LIGHT RAINFALL AMOUNTS...LIKELY LESS THAN QUARTER OF AN INCH.
HOWEVER...STEEP MID LEVEL LAPSE RATES AT/ABOVE 7 DEG C/KM AND
STRONG FORCING ALOFT MAY RESULT IN A STRONG STORM OR TWO CONTAINING
FREQUENT LIGHTNING AND POSSIBLY SMALL HAIL ACROSS THE WESTERN
COUNTIES LATER THIS MORNING. BEST LIFT SHIFTS SOUTH OF I-20 WITH
THE FRONT PUSHING TO THE TEXAS COAST THIS AFTERNOON...AS THIS
SYSTEM WILL BE MUCH MORE PROGRESSIVE THAN THE PREVIOUS WEEKEND
SYSTEM WAS. WILL CONTINUE A SLIGHT CHANCE ACROSS THE CENTRAL TEXAS
COUNTIES THIS AFTERNOON...BEFORE BOTH THE SHORTWAVE AND FRONT MOVE
AWAY FROM THE AREA BY EVENING.
HIGH PRESSURE WILL SETTLE IN TONIGHT WITH LIGHT WINDS AND MOSTLY
CLEAR SKIES. EXPECT A GOOD RADIATIONAL COOLING SET UP WITH LOWS
FALLING FALLING INTO THE 50S...THOUGH SOME ISOLATED READINGS IN
THE UPPER 40S CANNOT BE RULED OUT ACROSS PROTECTED RURAL AREAS.
HIGHS WILL REBOUND INTO THE UPPER 70S ACROSS THE EAST TO THE MID
80S IN THE WEST WEDNESDAY. THE UPPER RIDGE WILL CONTINUE EXPANDING
OVERHEAD THURSDAY AND FRIDAY WITH A MODERATION OF TEMPERATURES.
HIGHS BY FRIDAY WILL SOAR TO NEAR 90 DEGREES...BUT THE HUMIDITY
SHOULD BE RELATIVELY LOW. THE GREAT LAKES VORTEX WILL DEEPEN BY
LATE FRIDAY INTO THE WEEKEND AND WILL DRAG ANOTHER COLD FRONT INTO
NORTH TEXAS SATURDAY OR POSSIBLY SATURDAY NIGHT DEPENDING ON
WHETHER YOU BUY THE SLOWER ECMWF OR FASTER GEM/GFS MODELS. HAVE
TAKEN A MEAN ON THE TIMING AND WARMED HIGHS BACK UP SLIGHTLY ON
SATURDAY. WITH MOISTURE AVAILABILITY NOT LOOKING VERY GOOD WITH
THIS FRONT...HAVE DECIDED TO LEAVE THE FORECAST NEXT WEEKEND DRY.
05/
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 78 57 81 62 85 / 10 0 0 5 5
WACO, TX 80 56 83 59 85 / 20 0 0 0 5
PARIS, TX 75 52 78 55 84 / 10 0 0 5 5
DENTON, TX 78 53 82 60 87 / 10 0 0 5 5
MCKINNEY, TX 77 53 80 57 87 / 10 0 0 5 5
DALLAS, TX 79 59 81 64 86 / 10 0 0 5 5
TERRELL, TX 78 54 80 57 85 / 10 0 0 5 5
CORSICANA, TX 80 55 81 57 85 / 10 5 0 0 5
TEMPLE, TX 81 56 82 58 85 / 20 5 0 0 5
MINERAL WELLS, TX 76 55 84 60 87 / 20 0 0 5 5
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
05/
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
1155 AM CDT TUE SEP 18 2012
.UPDATE...
FORECAST TEMPS APPEAR TO BE ON TRACK SO FAR AND MATCH UP WELL WITH
925 MB TEMPS OF AROUND 8 DEGREES NORTHEAST TO 10 DEGREES
SOUTHWEST. STILL KEEPING SLIGHT CHANCE OF SHOWERS IN THE
FORECAST...AS THE LEFT EXIT REGION OF A 250 MB JET MOVES THROUGH
AND THE 500 MB TROUGH EXITS. THE HRRR AND RUC SHOW SOME SPOTTY
DEVELOPMENT THIS AFTERNOON AS WELL AND THERE IS SOME
DEVELOPMENT ALREADY OCCURRING...MAINLY IN NORTHEAST WISCONSIN.
&&
.AVIATION/18Z TAFS/...
VFR CONDITIONS ARE EXPECTED FOR THE ENTIRE PERIOD. THERE IS STILL
A SLIGHT CHANCE FOR SHOWERS THIS AFTERNOON...MAINLY EAST OF
MADISON...AS AN UPPER TROUGH AND JET SHIFT EAST. SCATTERED TO
BROKEN CLOUD COVER EXPECTED AROUND 4.5 TO 5.5 KFT THIS AFTERNOON.
THEN CLEAR SKIES TONIGHT WITH SOME MID TO HIGH CLOUDS BUILDING
IN LATE. COULD SEE SCATTERED TO BROKEN DECK AROUND 9 KFT BY EARLY
TOMORROW MORNING...AHEAD OF A COLD FRONT THAT WILL PASS THROUGH MSN
BETWEEN 21 AND 00Z TOMORROW. LOOKS LIKE PRECIPITATION WILL HOLD
OFF WITH THE FRONT UNTIL MID TO LATE AFTERNOON IN MSN AND LATER IN
THE EASTERN AREAS. ALSO...STRONG SOUTH TO SOUTHWEST WINDS ARE
EXPECTED AHEAD OF THE FRONT ON WEDNESDAY.
&&
.MARINE...
A SMALL CRAFT ADVISORY REMAINS IN EFFECT FOR THE NEARSHORE WATERS
INTO THIS EVENING AS A TROUGH OF LOW PRESSURE SLIDES EAST AND HIGH
PRESSURE BUILDS INTO THE REGION. STRONG SOUTH TO SOUTHWEST WINDS
ARE EXPECTED TOMORROW AS A COLD FRONT APPROACHES. A SMALL CRAFT
ADVISORY OR POSSIBLY A GALE WARNING WILL BE NEEDED.
&&
.PREV DISCUSSION... /ISSUED 333 AM CDT TUE SEP 18 2012/
TODAY AND TONIGHT...FORECAST CONFIDENCE...MEDIUM TO HIGH
COLD ADVECTION WILL WEAKEN LATER THIS MORNING BUT A 540 DM THICKNESS
TROUGH WILL PROGRESS ACROSS WI TODAY. FCST SOUNDINGS INDICATE JUST
ENOUGH DEPTH TO SHALLOW CAPE FOR ISOLD LGT SHOWERS THIS AFTERNOON.
SCT-BKN CUMULUS THIS AFTERNOON AND 925 MB TEMPS AROUND 9C ONLY
YIELDS HIGH TEMPS AROUND 60F. A NARROW SFC RIDGE AXIS WILL THEN
SHIFT FROM WEST TO EAST ACROSS WI THIS EVENING INTO THE EARLY
OVERNIGHT WITH TEMPS COOLING QUICKLY. HOWEVER MID TO HIGH CLOUDS
INCREASE LATE DUE TO MID LEVEL WARM ADVECTION DEVELOPING AHEAD OF A
DIGGING 120 KT JET AND ASSOCIATED SHORTWAVE TROUGH/SFC LOW FROM SASK
AND MANITOBA CANADA. THUS EXPECT PATCHY/AREAS OF FROST INLAND WITH
LOW TEMPS IN THE MID TO UPPER 30S...VERSUS COLDER TEMPS AND
WIDESPREAD FROST IF MORE IDEAL RADIATIONAL COOLING CONDITIONS WERE
EXPECTED.
WEDNESDAY...FORECAST CONFIDENCE...MEDIUM
DECENT COLD FRONT AND TRAILING SHORTWAVE TO MOVE THROUGH ON
WEDNESDAY. PLENTY OF LIFT WITH FRONTOGENESIS AND Q-VECTOR
CONVERGENCE. MODELS ALSO SHOWING 40-45KT LOW LEVEL JET AHEAD OF THE
FRONT RIGHT OVER SOUTHERN WISCONSIN. MOISTURE COULD DEFINITELY BE
BETTER...BUT SEEMS TO BE VIGOROUS ENOUGH OF A SYSTEM TO RAISE POPS
TO HIGH CHANCE. BEST CHANCE SEEMS LIKE IT WILL BE LATE AFTERNOON AND
INTO THE EVENING WITH CURRENT MODEL TIMING OF THE FRONT.
OTHER STORY WEDNESDAY WILL BE THE STRONG SOUTHERLY WINDS. A TIGHT
PRESSURE GRADIENT IS EXPECTED TO SETUP OVER SOUTHERN
WISCONSIN...WITH GUSTS OF 30-40 MPH EXPECTED. THE GRADIENT IS
TIGHTER WITH THE NAM...SUGGESTING GUSTS COULD POSSIBLY APPROACH
WIND ADVISORY CRITERIA. STUCK WITH THE MIDDLE GROUND FOR NOW...BUT
EITHER WAY...WILL LIKELY BE THE WINDIEST DAY IN A WHILE.
WITH SOME SUN EXPECTED IN AT LEAST THE MORNING...SHOULD SEE HIGHS
SNEAK UP INTO THE LOW 70S...AS 925 MB TEMPS SURGE AHEAD OF THE
FRONT. COULD SEE TEMPS EVEN MILDER IF MILDER NAM 925 MB TEMPS
VERIFY.
THURSDAY AND FRIDAY...FORECAST CONFIDENCE...MEDIUM
SHOULD SEE QUIET WEATHER BRIEFLY DURING THE DAY THURSDAY AS HIGH
PRESSURE SLIDES BY TO THE SOUTH. EXPECTING SOME SUN IN AT LEAST THE
MORNING AGAIN...SO BUMPED HIGHS UP A BIT WITH 925 MB TEMPS
SUGGESTING HIGHS AROUND 70.
KEPT SOME POPS IN THERE FOR THURSDAY NIGHT AND FRIDAY AS ANOTHER
SHORTWAVE AND COLD FRONT MOVE THROUGH. MODELS CONTINUE TO BOUNCE
AROUND WITH LOCATION OF BEST FORCING AND MOISTURE...SO NOT A LOT
OF CONFIDENCE WITH THE DETAILS OF THIS ONE. DOES LOOK COOLER
FRIDAY UNDER NORTHWEST WINDS BEHIND THE FRONT.
SATURDAY THROUGH MONDAY...FORECAST CONFIDENCE...MEDIUM
YET ANOTHER SHORTWAVE EXPECTED SATURDAY...POSSIBLY BRINGING MORE
SHOWERS TO THE AREA. HIGH PRESSURE TO THEN SLIDE THROUGH THE REGION
SUNDAY AND MONDAY...BRINGING QUIETER WEATHER TO SOUTHERN WISCONSIN.
COOLER AIR EXPECTED TO CONTINUE THROUGH THE WEEKEND...WARMING BACK
TO AROUND NORMAL EARLY NEXT WEEK.
AVIATION/12Z TAFS/...
VFR CONDITIONS WILL PREVAIL TODAY AND TONIGHT. SCT STRATUS AROUND
1 KFT MAY CONTINUE THROUGH THE EARLY MORNING IN ERN WI BUT
DIMINISH BY 14-15Z. SCT-BKN CUMULUS AROUND 7 KFT IS THEN EXPECTED
BY LATE MORNING THROUGH THE AFTERNOON WITH A SLIGHT CHANCE OF
SHOWERS AS AN UPPER TROUGH AXIS SHIFTS EAST ACROSS SRN WI. HIGH
PRESSURE AND MO CLEAR SKIES FOR MOST OF TNT WITH MID TO HIGH
CLOUDS INCREASING WED AM.
MARINE...
SMALL CRAFT ADVISORY REMAINS IN EFFECT FOR THE NEARSHORE WATERS INTO
THIS EVENING AS BRISK NNWLY WINDS AND HIGH WAVES CONTINUE IN THE
WAKE OF A COLD FRONT AND AIDED BY UNSTABLE CONDITIONS OVER THE LAKE.
HIGH PRESSURE WILL THEN COME ACROSS THE LAKE TONIGHT WITH MUCH
LIGHTER WINDS AND SUBSIDING WAVES. BREEZY SSWLY WINDS WILL THEN
DEVELOP WEDNESDAY AS STRONG LOW PRESSURE MOVES ACROSS SRN CANADA. A
SMALL CRAFT ADVISORY OR POSSIBLY A GALE WARNING MAY BE NEEDED.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 10 PM CDT THIS EVENING FOR LMZ644>646.
SMALL CRAFT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR LMZ643.
&&
$$
UPDATE...MEB
TODAY/TONIGHT AND AVIATION/MARINE...GEHRING
WEDNESDAY THROUGH MONDAY...DDV
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1142 PM CDT WED SEP 19 2012
.AVIATION...
COLD FRONT HAS NOW MOVED THROUGH ALL OF THE TERMINALS...LEAVING US
WITH NORTHWEST WINDS AT OR BELOW 10KTS. THIS...ALONG WITH VFR
CONDITIONS WILL CONTINUE THROUGH 21ST AT 06Z. SOME MID AND HIGH
CLOUDS...BUT WITH BASES ABOVE 8KFT. THURSDAY MORNING NORTHWEST
WINDS SHOULD INCREASE TO 10-15KTS WITH SOME SITES GUSTING TO
AROUND 20KTS DUE TO PRESSURE GRADIENT ACROSS AREA. AROUND
00Z/SUNSET... WINDS TO DIMINISH AGAIN TO LESS THAN 10KTS. PLENTY
OF MID AND HIGH CLOUDS THROUGH THE PERIOD...STILL WITH BASES ABOVE
10KFT. LE
&&
.PREV DISCUSSION... /ISSUED 306 PM CDT WED SEP 19 2012/
SYNOPSIS...
12Z UA ANALYSIS HAD A STRONG UPPER LOW EAST OF LAKE WINNIPEG. THE
850MB COLD FRONT RAN FROM THE ARROW HEAD OF MINNESOTA TO EASTERN
WYOMING. THE 850MB WARM FRONT RAN SOUTH ROUGHLY ALONG THE
MISSISSIPPI RIVER. STRONG CAA WAS OCCURRING BEHIND THE UPPER FRONT
WITH 850MB TEMPERATURES QUICKLY DROPPING INTO THE SINGLE DIGITS AT
THE INTERNATIONAL BORDER. SATELLITE TRENDS THROUGH MID AFTERNOON
SHOW RAPID DEVELOPMENT OF CLOUDS ALONG THE SFC COLD FRONT FROM
SOUTHEAST MINNESOTA INTO NORTHWEST IOWA. RADARS WERE SHOWING VIRGA
DEVELOPING FROM NORTHEAST IOWA INTO WESTERN WISCONSIN.
18Z SFC ANALYSIS HAD THE COLD FRONT RUNNING FROM THE KDLH AREA TO
SOUTHEAST COLORADO. A NARROW TONGUE OF LOW AND MID 50 DEW POINTS RAN
FROM THE SOUTHERN PLAINS INTO WESTERN IOWA. DEW POINTS IN THE 40S
WERE COMMON ACROSS MUCH OF THE MIDWEST AND WESTERN GREAT LAKES. DEW
POINTS IN THE 30S WERE ACROSS THE NORTHERN PLAINS AND GREAT LAKES.
SHORT TERM...TONIGHT AND THURSDAY...
BASED ON RADAR TRENDS...VIRGA IS BECOMING MORE PRONOUNCED FROM THE
CU FIELD THAT IS DEVELOPING ALONG THE COLD FRONT AND PRE-FRONTAL
TROF. RAP TRENDS CONTINUE TO SHOW MID LEVEL FORCING WILL INCREASE
THROUGH THE REMAINDER OF THE AFTERNOON WITH IT MAXIMIZING RIGHT
AROUND 00Z. FCST SOUNDINGS INDICATE CLOUD BASES IN THE 7-10 KFT AGL
RANGE SO THE VIRGA SHOULD BE QUITE OBVIOUS LATE THIS AFTERNOON IN
THE NORTHWEST PART OF THE CWFA WITH IT POTENTIALLY COMING FROM RADAR
RETURNS OF 30 DBZ OR HIGHER. EVENTUALLY...PRECIP WILL REACH THE
GROUND SO THE SCHC/CHC FOR LATE THIS AFTERNOON STILL LOOKS OKAY.
THE FRONT WILL SWEEP ACROSS THE CWFA DURING THE EVENING HOURS. AS
THE FORCING REACHES A MAXIMUM EARLY THIS EVENING THE POTENTIAL FOR A
COUPLE OF TSRA RIGHT ALONG THE FRONT IS POSSIBLE. HOWEVER...THE
NUMBER OF TSRA SHOULD BE NO MORE THAN A HANDFUL. THERE SHOULD STILL
BE CONSIDERABLE VIRGA INTO THE EARLY EVENING WITH THE MEASURABLE
RAIN LIKELY CONFINED TO A NARROW BAND ALONG THE FRONT.
BY MID EVENING THE RAIN SHOULD BE EAST OF THE MISSISSIPPI AND EXIT
THE AREA BY MIDNIGHT. STRONG SUBSIDENCE BEHIND THE SHORTWAVE SHOULD
RESULT IN SKIES CLEARING FAIRLY QUICKLY. AS THE HIGH BUILDS IN WINDS
SHOULD BECOME LIGHT WHICH WILL ALLOW TEMPERATURES TO DROP AS THE
SKIES CLEAR. THE WAPSI VALLEY ALONG WITH FAVORED COLD AREAS IN THE
NORTHERN CWFA SHOULD SEE THE COOLEST TEMPERATURES BY SUNRISE
THURSDAY.
ON THURSDAY QUIET AND DRY CONDITIONS WITH COOLER TEMPERATURES WILL
BE SEEN AS HIGH PRESSURE QUICKLY MOVES ACROSS THE AREA. ..08..
LONG TERM...THURSDAY NIGHT THROUGH NEXT WEDNESDAY...
THE EXTENDED FORECAST REMAINS VERY ACTIVE WITH MANY PASSING STRONG
SHORT WAVES ROUNDING THE BASE OF A STRONG UPPER AIR TROF IN THE
GREAT LAKES. THIS RESULTS IN SEVERAL DAYS OF FORECAST RAIN
CHANCES...WHICH ARE ALL LOW IN CONFIDENCE DUE TO THE CHANGEABLE
FORCING FORECAST FROM RUN TO RUN...AND MODEL TO MODEL. MUCH HIGHER
CONFIDENCE IS THAT WE WILL SEE A VERY COOL PERIOD OF DAYS...FOLLOWED
BY MODERATE WARMING. BY THURSDAY NIGHT THE PATTERN WILL ALREADY BE
ESTABLISHED...WITH THE 1ST OF SEVERAL WAVES ALREADY APPROACHING.
THIS SHOULD GENERATE WARM ADVECTION THEN STRONGLY FORCED COLD
FRONTAL SHOWERS FROM LATE THURSDAY NIGHT THROUGH FRIDAY MORNING.
RAINFALL AMOUNTS SHOULD BE LIGHT...BUT COULD BE UP TO 0.25 IN
SPOTS...ESPECIALLY NORTHEAST. FRIDAY LOOKS TO BE BLUSTERY UNDER
THE CLOUD COVER...THEN AFTER SEVERAL HOURS OF EASING EVENING
WINDS...AND CLEAR SKIES...WE WILL SEE A VERY STRONG UPPER WAVE DROP
SOUTH. THIS FRONT WILL SWEEP THROUGH EARLY SATURDAY...RESULTING IN
GUSTY NORTH WINDS...AND VERY STRONG COLD ADVECTION. SATURDAYS
TEMPERATURES FORECAST WITH HIGHS IN THE MID 50S NORTH TO LOWER 60S
SOUTH SEEMS OPTIMISTIC DESPITE IT BEING LOWER THAN MOST GUIDANCE.
SHOULD RAIN LINGER INTO THE DAY FOR MORE THAN A FEW HOURS...WE COULD
SEE HIGHS IN THE 40S...WITH PLENTY OF WIND. SHOULD SUNSHINE BECOME
WIDESPREAD SATURDAY AFTERNOON...RESULTING IN DEEPER MIXING...A WIND
ADVISORY IS NOT OUT OF THE QUESTION.
SATURDAY NIGHT...AND SUNDAY NIGHT...A FROST OR FREEZE IS POSSIBLE.
THIS PAST MORNING...WITH ONLY 1/2 OF A NIGHT SEEING CLEAR SKIES...WE
HIT THE MID 30S WITH 850MB TEMPERATURES OF 3 DEGREE. BOTH UPCOMING
NIGHTS THIS WEEKEND SHOULD SEE 850MB TEMPS OF +1 TO -2 DEGREES.
WHILE WINDS MAY NOT BE AS LIGHT...THIS SHOULD STILL RESULT IN COOLER
NIGHTS THAN LAST NIGHT. FOR NOW...UNTIL WE ARE CERTAIN...WILL KEEP
LOWS OF MID 30S FORECAST. SUNDAY ITSELF SHOULD BE A PLEASANT BUT
COOL DAY IN THE UPPER 50S TO LOWER 60S...AS WIND SHOULD BE LESS OF
AN ISSUE.
MONDAY INTO TUESDAY...MODERATING TEMPERATURES AND A DEVELOPING
SOUTHERLY FLOW SHOULD ALLOW FOR TEMPERATURES TO RETURN TO THE UPPER
60S MONDAY...AND MID 70S TUESDAY. TUESDAY INTO WEDNESDAY...MOISTURE
ADVECTION OVER A DEVELOPING WARM FRONT NEARBY SHOULD ALLOW FOR RAIN
POSSIBILITIES...AND POSSIBLE CONVECTION.
ERVIN
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
423 AM EDT THU SEP 20 2012
.SYNOPSIS...
HIGH PRESSURE WILL ALLOW FOR DRY WEATHER TO CONTINUE UNTIL THE
APPROACH OF A STRONG COLD FRONT LATE ON FRIDAY. IN THE WAKE OF THE
FRONT, MUCH COOLER AIR WILL SETTLE INTO THE REGION SATURDAY
THROUGH EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
THE LATEST RAP MID-LEVEL ANALYSIS INDICATES A 500MB TROUGH AXIS
CENTERED ACROSS THE UPPER MIDWEST WITH THE UPPER OHIO VALLEY IN A
RELATIVELY DRY SOUTHWESTERLY FLOW AHEAD OF THIS FEATURE. AT THE
SURFACE, A 1026MB HIGH IS CENTERED ACROSS MAINE WITH A 998MB
SURFACE LOW JUST NORTHWEST OF LAKE SUPERIOR. A COLD FRONT EXTENDS
SOUTHWARD OF THE LOW ACROSS ILLINOIS AND INTO THE MISSOURI VALLEY.
WELL AHEAD OF THE FRONT, SKIES REMAIN CLEAR WITH NEAR CALM WINDS
ACROSS THE UPPER OHIO VALLEY.
TODAY AND TONIGHT...THE TROUGH WILL MOVE EASTWARD INTO THE GREAT LAKES
REGION WITH THE COLD FRONT SWINGING INTO THE OHIO VALLEY AND
AIDING WARM AIR ADVECTION. WITH A DEEP LAYER OF DRY AIR IN PLACE, SKIES
WILL BE SUNNY UNTIL LATE IN THE DAY AS MOISTURE ALONG THE WEAK
COLD FRONT ADVECTS ACROSS THE AREA AND INCREASES CLOUDINESS
OVERNIGHT. A THERMAL RIDGE WILL BUILD INTO THE AREA TODAY WITH
WAA (850MB TEMPS INCREASING FROM 6C TO 12C). THIS IN COMBINATION
WITH ABUNDANT SUNSHINE WILL ALLOW TEMPS TO BE AROUND 10 DEGREES
WARMER IN COMPARISON TO WEDNESDAY. HIGHS WILL WARM INTO THE LOWER
70S ACROSS MOST OF THE LOWLANDS, WITH MID 60S ANTICIPATED FOR THE
HIGHER ELEVATIONS IN THE EASTERN RIDGES. LOWS TONIGHT WILL BE NEAR
SEASONAL NORMALS, IN THE LOWER 50S ACROSS MUCH OF THE AREA, AS
CLOUD COVERAGE INHIBITS RADIATIONAL COOLING.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
GFS/NAM ARE IN AGREEMENT THAT A STRONG COLD FRONT WILL CROSS THE
OHIO VALLEY ON FRIDAY AND REACH THE EASTERN OHIO ZONES BY 06Z ON
SATURDAY. THE FRONT WILL PUSH INTO WESTERN PA SATURDAY MORNING AND
CLEAR THE EASTERN RIDGES BY SATURDAY EVENING. LIKELY POPS ARE
FORECAST WITH THE PASSAGE OF THE FRONT WITH SCHC THUNDER IN WEAK
SURFACE-BASED INSTABILITY ALONG AND SOUTH OF THE MASON-DIXON LINE.
THE CHANCE OF SHOWERS WILL LINGER BEHIND THE FRONT ON SATURDAY AS
500MB HEIGHTS CONTINUE TO LOWER AND THE BEST MID-LEVEL FORCING
WITH THE TROUGH PUSHES INTO THE AREA. THE HIGHEST QPF (QUARTER TO
HALF OF AN INCH) IS FOCUSED NORTHWEST OF PITTSBURGH AS STRONGER
1000MB-700MB FRONTOGENETICAL FORCING CROSSES THIS AREA FRIDAY
NIGHT. ELSEWHERE, LESS THAN A QUARTER OF AN INCH OF RAINFALL IS
FORECAST WITH THE FRONTAL PASSAGE.
SATURDAY NIGHT INTO SUNDAY...OPERATIONAL MODELS ARE IN AGREEMENT
THAT THE MID-LEVEL TROUGH AXIS WILL SWING ACROSS THE AREA WITH THE
REINFORCEMENT OF FORCING FROM A SHORT WAVE ALONG WITH ONGOING COLD
AIR ADVECTION. THUS, THE CHANCE OF SHOWERS CONTINUES FOR LOCATIONS
PRIMARILY NORTH OF PITTSBURGH AND ACROSS THE EASTERN RIDGES.
FOR TEMPERATURES, HIGHS ON FRIDAY LEAN CLOSER TO THE SLIGHTLY WARMER
ECMWF GUIDANCE IN WAA AHEAD OF THE COLD FRONT. WITH THE FRONTAL
PASSAGE, LOW TEMPS ARE A GFS/ECMWF BLEND, AROUND 5 DEGREES ABOVE
NORMAL AHEAD OF THE FRONT ON FRIDAY NIGHT DECREASING TO AROUND 5
DEGREES BELOW NORMAL IN THE WAKE OF THE FRONT. FOR HIGHS, A CANADIAN
AIR MASS WILL BE ADVECTING INTO THE AREA IN THE WAKE OF THE FRONT
ON SATURDAY AND BUILD INTO THE AREA BY SUNDAY. THUS, TEMPS WILL BE
FAIRLY STEADY IN THE MID 60S BEHIND THE FRONT ON SATURDAY AND ONLY
REACHING THE LOWER 60S ACROSS MOST OF THE AREA ON SUNDAY.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
BLEND OF RECENT NAEFS AND ECMWF ENSEMBLE MODEL OUTPUT SHOW A COLD
UPPER LEVEL TROUGH PASSING EXITING EAST MONDAY WITH HIGH PRESSURE
FOLLOWING TUESDAY AND WEDNESDAY.
RESULTING COLD POOL INSTABILITY SUNDAY WILL YIELD AT LEAST
AFTERNOON CLOUDINESS ACROSS MUCH OF THE UPPER OHIO VALLEY SUNDAY
WITH SCATTERED SHOWERS NORTH AND NEAR THE MOUNTAINS.
EXPECT LESS CLOUDS MONDAY WITH FAIRLY CLEAR SKIES TUESDAY AND
WEDNESDAY.
JUDGING FROM NAEFS MEDIAN VALUES AND ECMWF MOS...FORECASTED HIGH
TEMPERATURES TO BE ABOUT 10 DEGREES COLDER THAN NORMAL SUNDAY...THEN
SLOWLY WARMING TO BE NEAR NORMAL WEDNESDAY.
FORECASTED LOW TEMPERATURES TO REMAIN 5 TO 10 DEGREES COLDER THAN
NORMAL EACH MORNING.
&&
.AVIATION /08Z THURSDAY THROUGH MONDAY/...
EXPECT VFR THROUGH TODAY...DUE TO HIGH PRESSURE SUBSIDENCE WITH
GENERALLY CLEAR SKIES AND SOME DAYTIME SCATTERED CUMULUS CLOUDS.
PATCHES OF RIVER VALLEY FOG CAN FORM EARLY THIS MORNING BUT ITS
TOO DRY TO SPREAD VISIBILITY RESTRICTIONS TO ANY OF THE UPLAND TAF
SITES.
.OUTLOOK /FRIDAY THROUGH MONDAY/...
EXPECT VFR FRIDAY TO BECOME PUNCTUATED BY RESTRICTIONS FRIDAY
AFTERNOON INTO SUNDAY AFTERNOON DUE TO SHOWERS ASSOCIATED WITH A
COLD FRONTAL PASSAGE FRIDAY NIGHT AND COLD UPPER TROUGH THIS
WEEKEND. EXPECT TREND TOWARD PREVALENT VFR MONDAY AS LAST OF
STRATOCUMULUS CEILINGS LIFT OR DISSIPATE.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...FROST ADVISORY UNTIL 9 AM EDT THIS MORNING FOR MDZ001.
OH...NONE.
PA...FROST ADVISORY UNTIL 9 AM EDT THIS MORNING FOR PAZ009.
WV...NONE.
&&
$$
SYNOPSIS...WOODRUM
NEAR TERM...WOODRUM
SHORT TERM...WOODRUM
LONG TERM...
AVIATION...
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
229 AM EDT THU SEP 20 2012
.SYNOPSIS...
HIGH PRESSURE WILL ALLOW FOR DRY WEATHER TO CONTINUE UNTIL THE
APPROACH OF A STRONG COLD FRONT LATE ON FRIDAY. IN THE WAKE OF THE
FRONT, MUCH COOLER AIR WILL SETTLE INTO THE REGION SATURDAY
THROUGH EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
06Z ENHANCED SHORT TERM FORECAST HAS BEEN ISSUED TO ACCOUNT FOR
THE LATEST TEMP TRENDS. THE FROST ADVISORY REMAINS IN PLACE FOR
FOREST AND GARRETT COUNTIES.
THE LATEST RAP MID-LEVEL ANALYSIS INDICATES A 500MB TROUGH AXIS
CENTERED ACROSS THE UPPER MIDWEST WITH THE UPPER OHIO VALLEY IN A
RELATIVELY DRY SOUTHWESTERLY FLOW AHEAD OF THIS FEATURE. AT THE
SURFACE, A 1026MB HIGH IS CENTERED ACROSS MAINE WITH A 998MB
SURFACE LOW JUST NORTHWEST OF LAKE SUPERIOR. A COLD FRONT EXTENDS
SOUTHWARD OF THIS FEATURE ACROSS ILLINOIS AND INTO THE MISSOURI
VALLEY. WELL AHEAD OF THE FRONT, SKIES REMAIN CLEAR WITH NEAR CALM
WINDS ACROSS THE UPPER OHIO VALLEY.
TODAY...THE TROUGH WILL MOVE EASTWARD INTO THE GREAT LAKES REGION
WITH THE COLD FRONT WILL SWINGING INTO THE OHIO VALLEY AND A WEAK
WARM FRONT PUSHING NORTH OF THE AREA. WITH A DEEP LAYER OF DRY AIR
IN PLACE, SKIES WILL BE SUNNY UNTIL LATE IN THE DAY AS MOISTURE
ALONG THE WEAK COLD FRONT ADVECTS INTO THE AREA. A THERMAL RIDGE
WILL BUILD INTO THE AREA TODAY WITH WARM AIR ADVECTION TAKING
PLACE (850MB TEMPS INCREASING FROM 6C TO 12C). THIS IN COMBINATION
WITH ABUNDANT SUNSHINE WILL ALLOW TEMPS TO BE AROUND 10 DEGREES
WARMER IN COMPARISON TO WEDNESDAY. HIGHS WILL WARM INTO THE LOWER
70S ACROSS MOST OF THE LOWLANDS, WITH MID 60S ANTICIPATED FOR THE
HIGHER ELEVATIONS IN THE EASTERN RIDGES.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY/...
THE AFOREMENTIONED CDFNT IS PROJECTED TWD THE UPR OH ON THU...BUT
WITH A LACK OF RAIN-SUPPORTING MSTR. EXPECT AN INCREASE IN CLOUDS
WITH MODERATING TEMPS IN THE WARM ADVCTN IN ADVN OF THE FRONT.
A MUCH STRONGER SYSTEM IS PROGGED TO MOVE THROUGH THE UPPER MIDWEST
FRIDAY. THAT DISTURBANCE WL FURTHER AMPLIFY THE BROAD ERN NORTH
AMERICAN TROF AND WL LIKELY SPAWN SOME SHRA OVR NWRN ZONES BY LATE
AFTN OR EVE. CHC POPS WERE CONTD FOR THE OVRNGT PD AND INTO
SATURDAY AS THE MAIN MID LVL TROF AXIS AND COLD POOL ENCROACH OVR
THE AREA.
MUCH COLDER TEMPS SHOULD BE EXPECTED IN THE WAKE OF THIS PARTICULAR
FRONT...FORECAST WAS CONSTRUCTED WITH A LEAN TWD THE COOLER NAM.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
BLEND OF RECENT NAEFS AND ECMWF ENSEMBLE MODEL OUTPUT SHOW A COLD
UPPER LEVEL TROUGH PASSING EASTWARD THROUGH THE GREAT LAKES AND
UPPER OHIO VALLEY SUNDAY...EXITING EAST MONDAY WITH HIGH PRESSURE
FOLLOWING TUESDAY AND WEDNESDAY.
RESULTING COLD POOL INSTABILITY SUNDAY WILL YIELD AT LEAST
AFTERNOON CLOUDINESS ACROSS MUCH OF THE UPPER OHIO VALLEY SUNDAY
WITH SCATTERED SHOWERS NORTH AND NEAR THE MOUNTAINS.
EXPECT LESS CLOUDS MONDAY WITH FAIRLY CLEAR SKIES TUESDAY AND
WEDNESDAY.
JUDGING FROM NAEFS MEDIAN VALUES AND ECMWF MOS...FORECASTED HIGH
TEMPERATURES TO BE ABOUT 10 DEGREES COLDER THAN NORMAL SUNDAY...THEN
SLOWLY WARMING TO BE NEAR NORMAL WEDNESDAY.
FORECASTED LOW TEMPERATURES TO REMAIN 5 TO 10 DEGREES COLDER THAN
NORMAL EACH MORNING.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
EXPECT VFR THROUGH THURSDAY...DUE TO HIGH PRESSURE SUBSIDENCE WITH
GENERALLY CLEAR SKIES AND SOME DAYTIME SCATTERED CUMULUS CLOUDS.
PATCHES OF RIVER VALLEY FOG CAN FORM EARLY THURSDAY MORNING BUT ITS
TOO DRY TO SPREAD VISIBILITY RESTRICTIONS TO ANY OF THE UPLAND TAF
SITES.
.OUTLOOK /FRIDAY THROUGH MONDAY/...
EXPECT VFR FRIDAY TO BECOME PUNCTUATED BY RESTRICTIONS FRIDAY
AFTERNOON INTO SUNDAY AFTERNOON DUE TO SHOWERS ASSOCIATED WITH A
COLD FRONTAL PASSAGE FRIDAY NIGHT AND COLD UPPER TROUGH THIS
WEEKEND. EXPECT TREND TOWARD PREVALENT VFR MONDAY AS LAST OF
STRATOCUMULUS CEILINGS LIFT OR DISSIPATE.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...FROST ADVISORY UNTIL 9 AM EDT THIS MORNING FOR MDZ001.
OH...NONE.
PA...FROST ADVISORY UNTIL 9 AM EDT THIS MORNING FOR PAZ009.
WV...NONE.
&&
$$
SYNOPSIS...WOODRUM
NEAR TERM...WOODRUM
SHORT TERM...
LONG TERM...
AVIATION...
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
558 AM EDT THU SEP 20 2012
.SYNOPSIS...
A DEEPENING UPPER TROUGH OVR THE GRT LKS WILL PUSH A COLD FRONT
THROUGH CENTRAL PA LATE SATURDAY. THE UPPER TROUGH WILL ROTATE
THROUGH THE REGION SUNDAY...FOLLOWED BY HIGH PRESSURE EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
EARLY AM MODIS 11-3.7UM IMAGERY SHOWING DENDRITIC PATTERN OF FOG
IN THE VALLEYS...THE RESULT OF A COOL...CALM MORNING AND RELATIVELY
WARM RIVER/STREAM WATERS. LATEST 3KM HRRR SFC RH FIELDS SUGGEST
THE MOST PERSISTENT FOG WILL BE UNDER SFC RIDGE AXIS ACROSS THE
SUSQ VALLEY...WHERE PATCHES COULD LINGER UNTIL 14Z-15Z.
LG SCALE SUBSIDENCE AND DRY AIR ASSOCIATED WITH HIGH PRESSURE SYSTEM
WILL PROVIDE THE AREA WITH ABUNDANT SUNSHINE LATER TODAY. GEFS 8H
TEMPS SHOW MODERATION OF THIS ONCE CHILLY AIR MASS WITH MEAN 8H
TEMPS NR 9C BY AFTN...SUPPORTIVE OF HIGHS IN THE U60S AND L70S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
DYING COLD FRONT...CURRENTLY OVR MICHIGAN...WILL PUSH INTO WESTERN
PA TONIGHT...ACCOMPANIED BY AN INCREASE IN CLOUDS...BUT LITTLE IF
ANY PRECIP. WILL RAMP UP POPS TO ARND 15 PCT OVERNIGHT ACROSS THE
W MTNS WITH ARRIVAL OF THIS WEAK FRONT. HOWEVER...NEARLY ALL THE LG
SCALE FORCING REMAINS WEST OF PA ASSOC WITH DEEPENING UPPER TROUGH...SO
THE CHANCE OF ANY -SHRA WILL BE MINIMAL. SOUTHERLY FLOW AHEAD OF
THIS BOUNDARY WILL DRAW HIGHER HUMIDITY BACK INTO THE REGION...RESULTING
IN A MUCH MILDER NIGHT...WITH MINS MOSTLY ARND 50F.
DYING COLD FRONT WILL WASH OUT OVR CENTRAL PA ON FRIDAY...PROVIDING
THE FOCUS FOR SCT AFTN -SHRA. WILL PLACE AXIS OF HIGHEST POPS
/ARND 30 PCT/ ACROSS THE CENTRAL COUNTIES...WHERE MDL DATA SHOWS
TONGUE OF HIGHER SFC-8H THTE.
DESPITE A PT-MOCLDY SKY...TEMPS SHOULD REACH NR SEASONAL NORMS
FRI AFTN DUE TO WARMER RETURN SOUTHERLY FLOW AS SFC RIDGE PASSES
OFF THE COAST.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
LITTLE SPREAD AMONG MED RANGE GUIDANCE WITH RESPECT TO THE LG
SCALE PATTERN OVR THE NORTHEAST CONUS THIS WEEKEND. ALL GUIDANCE
INDICATING UPPER LOW OVR ONTARIO GRADUALLY SHIFTS EAST...PUSHING A
COLD FRONT THRU CENTRAL PA LATER SAT OR SAT NIGHT. AS MDL DATA HAS
COME INTO LINE W/REGARDS TO TIMING OF FRONT...HAVE BUMPED POPS UP
TO LIKELY FOR SAT PM. MDL DATA HINTING THAT ENOUGH HEATING/DESTABILIZATION
WILL OCCUR AHEAD OF FROPA FOR MENTION OF THUNDER IN ADDITION TO
THE SHOWERS. SOME UNCERTAINTY W/REGARDS TO AMT OF PRE-FRONTAL
CLOUD COVER AND RESULTING CAPES. HOWEVER...STRONG DEEP LYR
SHEAR...COMBINED WITH EVEN MARGINAL INSTABILITY...COULD POSE THE
THREAT OF SVR WX OVR ROUGHLY THE EASTERN HALF OF THE STATE SAT
AFTN.
AS THE UPPER TROF AXIS CROSSES THE REGION ON SUNDAY...ADDITIONAL
SHOWERS ARE POSSIBLE ACROSS MAINLY WESTERN AND NORTHERN SECTIONS.
A RATHER TIGHT PRES GRADIENT WILL PRODUCE GUSTY W WIND ACROSS THE
REGION...ACCENTUATING THE POST-FRONT CHILL. GEFS MEAN 8H TEMPS
SUPPORT HIGHS FROM THE M50S NW MTNS TO THE U60S SE.
FAIR BUT STILL COOL WEATHER APPEAR LIKELY EARLY NEXT WEEK AS
UPPER TROUGH BEGINS TO LIFT OUT AND SFC HIGH PRES BUILDS EAST
ACROSS THE OHIO VALLEY. GEFS AND ECMWF MEAN 8H TEMPS REMAIN BLW
SEASONAL NORMS BOTH MON AND TUE. SFC HIGH PRES SYS WILL PASS OFF THE
MID ATLANTIC COAST BY MID WEEK...ALLOWING A MILDER SW FLOW TO
DEVELOP.
&&
.AVIATION /09Z THURSDAY THROUGH MONDAY/...
HIGH PRESSURE WILL REMAIN SITUATED OVER THE REGION LATE THIS WEEK.
EXPECT VFR CONDITIONS OVERNIGHT FOR THE MAJORITY OF LOCATIONS...
WITH SOME VALLEY FOG IMPACTING KIPT-KSEG WITH MVFR/IFR CONDITIONS
THROUGH SUNRISE. DID NOT MENTION FOR KBFD AS WIND GRADIENT PICKS
UP A LITTLE HEADING TOWARD SUNRISE.
DURING THE DAY THU...VFR CONDITIONS WILL PREVAIL WITH ONLY SOME
MID/HIGH CLOUDS STREAMING OVERHEAD. SURFACE WINDS DO PICK UP FROM
THE SOUTH...INCREASING TO 10 MPH WITH GUSTS APPROACHING 20 MPH.
OUTLOOK...
FRI...MAINLY VFR. ISOLATED SHOWERS COULD PRODUCE LOCAL MVFR
CONDITIONS.
SAT...MAINLY VFR BUT A PERIOD OF MVFR CONDITIONS POSSIBLE
IN LIKELY SHOWERS.
SUN...MAINLY VFR BUT MVFR CONDITIONS POSSIBLE ACROSS THE
HIGHER MTNS.
MON...VFR...AS HIGH BUILDS ACROSS THE REGION.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
FROST ADVISORY UNTIL 9 AM EDT THIS MORNING FOR PAZ005-006-010-
011.
&&
$$
SYNOPSIS...FITZGERALD
NEAR TERM...FITZGERALD
SHORT TERM...FITZGERALD
LONG TERM...FITZGERALD
AVIATION...RXR
AREA FORECAST DISCUSSION
NWS SACRAMENTO CA
415 AM PDT THU SEP 20 2012
.DISCUSSION...A LOW PRESSURE SYSTEM CONTINUES TO SPIN OFFSHORE
WHILE AN UPPER LEVEL HIGH PRESSURE SYSTEM REMAINS OVER THE WEST
COAST. THIS HIGH PRESSURE RIDGE IS CURRENTLY BRINGING CLEAR SKIES TO
THE FORECAST AREA THIS MORNING. THE LOW AND RIDGE ARE ONLY EXPECTED
TO MOVE SLIGHTLY TODAY SO NOT EXPECTING MUCH CHANGE IN AIRMASS.
TEMPERATURES THIS MORNING ARE RUNNING SIMILAR TO 24 HOURS AGO AND
EXPECTING TODAYS HIGHS TO COME IN SIMILAR TO WEDNESDAYS. THE
OFFSHORE UPPER LOW IS FORECAST BY ALL MODELS TO OPEN AND LIFT TO THE
NORTHEAST TOWARDS THE PACIFIC NORTHWEST ON FRIDAY. AIRMASS COOLS
JUST A BIT SO HIGHER ELEVATIONS MAY SEE A LITTLE COOLING FRIDAY. NAM
MODEL SHOWS JUST A BIT OF INSTABILITY IN THE MID LEVELS OVER THE
NORTHERN SIERRA ZONES. MOISTURE WILL BE LIMITED BUT WILL LIKELY BE
ENOUGH FOR SOME AFTERNOON CUMULUS. ALSO ADDED JUST A SLIGHT THREAT
OF AFTERNOON THUNDERSTORMS OVER THE FAR SOUTHEASTERN CWA. AIRMASS
COOLS A BIT MORE ON SATURDAY AS THE UPPER TROUGH BEGINS PUSHING INTO
THE PACIFIC NORTHWEST COAST. MODELS INDICATE RELATIVELY STABLE
SOUTHWEST FLOW ALOFT BUT MAY BE JUST ENOUGH LIFT AND INSTABILITY
OVER PORTIONS OF THE SIERRA CASCADE CREST TO PRODUCE SOME ISOLATED
THUNDERSTORM ACTIVITY. MODELS ARE IN BETTER AGREEMENT IN POSITION OF
THE TROUGH ON SATURDAY THAN IN PREVIOUS RUNS SO WITH MORE
CONFIDENCE...HAVE LOWERED POPS A BIT OVER THE SIERRA CASCADE CREST
REGION. MID RANGE MODELS NOW IN FAIRLY GOOD AGREEMENT IN DIGGING
UPPER TROUGH SOUTHWARD ON SUNDAY FORMING ANOTHER CLOSED LOW CENTERED
OVER NORTHEAST CALIFORNIA. MODELS STILL NOT SHAPING NORCAL UP TO BE
PARTICULARLY UNSTABLE BUT WITH PROXIMITY OF LOW OVER NORCAL...SLIGHT
THREAT OF AFTERNOON THUNDERSTORMS SEEMS FAIRLY REASONABLE AND
MATCHES WELL WITH SURROUNDING OFFICE FORECASTS.
&&
.EXTENDED DISCUSSION (MONDAY THROUGH THURSDAY)
BY MONDAY AFTERNOON...ALL MODELS NOW MOVE UPPER LOW CENTER INTO THE
GREAT BASIN. HAVE REDUCED THREAT OF THUNDERSTORMS OVER SIERRA FOR
MONDAY BUT RAP AROUND ACTIVITY COULD SPARK SOME ISOLATED
THUNDERSTORMS OVER THE CREST. MODELS DIVERGE SOMEWHAT BY NEXT
TUESDAY IN DEALING WITH ANOTHER WEAK PACIFIC TROUGH FORECAST TO MOVE
ONTO THE NORCAL COAST. AT THIS TIME...IT APPEARS THIS SYSTEM WILL BE
TOO WEAK TO PRODUCE A SIGNIFICANT THREAT OF SHOWERS OR
THUNDERSTORMS. GFS MOVES THIS LOW QUICKLY THROUGH NORCAL ON
WEDNESDAY WHILE GEM AND ECMWF DROP THE TROUGH SOUTHWARD FORMING A
CLOSED LOW SOMEWHERE ALONG THE CENTRAL CALIFORNIA COAST. GEM/ECMWF
SOLUTION WOULD BRING A THREAT OF SHOWERS OR THUNDERSTORMS TO THE
SIERRA CASCADE CREST WHILE GFS WOULD KEEP FORECAST AREA DRY ON
WEDNESDAY. WILL KEEP SLIGHT THREAT OF THUNDERSTORMS IN FOR THE
SIERRA CASCADE RANGE ON WEDNESDAY AND THURSDAY FORECAST PERIOD UNTIL
MODELS COME INTO BETTER ALIGNMENT. OTHERWISE MAINLY FAIR SKIES
CONTINUE WITH NEAR NORMAL TEMPERATURES.
&&
.AVIATION...
VFR CONDITIONS EXPECTED NEXT 24 HOURS EXCEPT POSSIBLE MVFR CONDITIONS
WITH PATCHY LOW CLOUDS IN THE DELTA REGION WEST OF KSUU THROUGH
16Z. SOUTHWEST WINDS UP TO 20 KTS IN THE DELTA...WITH TAF SITES
GENERALLY LESS THAN 12 KTS. -DVC
&&
.STO WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
950 AM EDT THU SEP 20 2012
.SYNOPSIS...
A WEAK COLD FRONT WILL MOVE INTO THE REGION AND DISSIPATE BY THIS
EVENING. A SERIES OF LOW PRESSURE SYSTEMS WILL THEN MOVE THROUGH
THE REGION FROM FRIDAY THROUGH SATURDAY. THESE WEATHER SYSTEMS
WILL PROVIDE A CHANCE OF RAIN FOR THE REGION. MUCH COOLER AIR WILL
MOVE IN BEHIND A COLD FRONT FOR SUNDAY AND EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SHOWERS AND ISOLATED THUNDERSTORMS HAVE BEEN PROGRESSING AHEAD OF
A WEAK COLD FRONT. CONVECTION HAS BEEN WEAKENING AS IT MOVES
ACROSS CENTRAL INDIANA BUT HELD TOGETHER FURTHER NORTH. APPEARS
THAT WEAKENING TREND WILL CONTINUE FURTHER EAST INTO THE FORECAST
AREA. BEST CHANCE OF RAIN WILL BE IN THE FAR NORTHWEST COUNTIES.
PAST FEW HRRR RUNS SUGGEST THAT SOME PRECIPITATION COULD MAKE IT
INTO CENTRAL OHIO. SO MAINTAINED SLIGHT CHANCE POPS GENERALLY
NORTH OF I-70 ALTHOUGH ANY RAIN MAY END UP BEING JUST TRACE
AMOUNTS. FORECAST TEMPERATURES LOOK REASONABLE AT THIS POINT WITH
ONLY MINOR ADJUSTMENTS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
THERE IS INCREASING MODEL CONFIDENCE IN THE GENERAL EVOLUTION OF A
TWO-PART WEATHER SYSTEM FOR FRIDAY AND SATURDAY...FORCING THE
INTRODUCTION OF LIKELY POPS INTO THE GRIDS.
A LARGE UPPER LEVEL TROUGH WILL CONTINUE TO DEEPEN OVER THE GREAT
LAKES REGION...WITH RELATIVELY QUICK MID AND UPPER LEVEL FLOW (WSW
TO ENE) ACROSS THE OHIO VALLEY. AN INITIAL WAVE IN THE FLOW IS
EXPECTED TO BRING THE HIGHEST CHANCES FOR PRECIPITATION TO THE
REGION...ESPECIALLY FOR SE INDIANA...THE MIAMI VALLEY...AND
CENTRAL OHIO. LOCATIONS FURTHER SOUTH MAY NOT BE IMPACTED BY THE
AXIS OF THE HIGHEST RAINFALL AMOUNTS. THERE IS ENOUGH AGREEMENT
IN TIMING THIS FEATURE TO INCLUDE LIKELY POPS IN THESE AREAS...BUT
STILL A BIT TOO MUCH UNCERTAINTY TO USE AN 80 PERCENT CHANCE OR
HIGHER. THE NAM12 REMAINS A RATHER QUICK OUTLIER...THOUGH THE GFS
IS ALSO FASTER THAN THE ECMWF/CMC. UP TO AN INCH OF RAIN IS
EXPECTED.
FORECAST AGREEMENT HAS ALSO IMPROVED SOMEWHAT WITH A SECOND (AND
MUCH STRONGER) DISTURBANCE THAT MOVES VERY QUICKLY SOUTHEAST FROM
MINNESOTA ON SATURDAY. DEPICTED AS A TIGHT MID-LEVEL CLOSED
LOW...WITH A TRAILING COLD FRONT...THE COLD/DRY ADVECTION TO THE
SOUTH OF THE LOW TRACK WILL BE PRONOUNCED. THERE WILL BE A DEFINED
BREAK IN BETWEEN THE TWO WEATHER SYSTEMS...AND PRECIPITATION WITH
THE SATURDAY SYSTEM IS EXPECTED TO PRIMARILY REMAIN NORTH OF THE
CWA. THE NORTHERN COUPLE OF TIERS OF COUNTIES WILL PROBABLY BE
IMPACTED BY CONVECTIVELY-INDUCED SHOWERS. AS THE DEEP TROUGH
REMAINS NEAR THE AREA (THOUGH ITS AXIS WILL BE TO THE NE)...A
SIMILAR (THOUGH LESS PRONOUNCED) SITUATION WILL BE POSSIBLE ON
SUNDAY...WITH QUITE A BIT OF DIURNAL CLOUD COVER AND A SLIGHT
CHANCE OF SOME LIGHT SHOWERS IN CENTRAL OHIO.
THE TEMPERATURE FORECAST IS SOMEWHAT CHALLENGING...GIVEN THE
OCCASIONAL LOW PRESSURE SYSTEMS AND PRECIPITATION
CHANCES...FOLLOWED BY AN IMPRESSIVE MASS OF COOL AIR. THE COLD
POOL ALOFT (BY SUNDAY AND SUNDAY NIGHT) WILL BE UP TO TWO STANDARD
DEVIATIONS BELOW CLIMO...AND WITH THE SURFACE HIGH IN PLACE ON
SUNDAY NIGHT...THE LOWS MONDAY MORNING WILL BE COLD. AS HAS BEEN
THE TREND FOR THE PAST FEW SHIFTS...TEMPS ON SUNDAY AND MONDAY
HAVE BEEN DECREASED ANOTHER DEGREE OR TWO...WITH POTENTIALLY
FROST-INDUCING TEMPS IN THE GRIDS FOR SUNDAY NIGHT / MONDAY
MORNING.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
A GRADUAL WARMUP OF 4-5 DEGREES WILL OCCUR EACH DAY AFTER SUNDAY
AND SUNDAY NIGHT UNDER PARTLY CLOUDY SKIES...REACHING BACK TO
CLIMATOLOGICAL NORMS IN THE LOW 70S ON TUESDAY AND SURPASSING THEM
WITH MID TO UPPER 70S ON WEDNESDAY.
&&
.AVIATION /14Z THURSDAY THROUGH MONDAY/...
FOR TODAY...THE WEAK COLD FRONT WILL SLOWLY PUSH EAST INTO THE
REGION. THE FRONT IS MOISTURE STARVED AND MAINLY MID LEVEL CLOUDS
WILL MOVE IN ADVANCE OF IT. ANY LIGHT SHOWERS OR SPRINKLES SHOULD
REMAIN NORTH AND WEST OF THE TAF SITES. AN INCREASING PRESSURE
GRADIENT AND DAY TIME MIXING WILL ALLOW WINDS TO INCREASE FROM THE
SOUTH SOUTHWEST AROUND 15 KNOTS WITH GUSTS BETWEEN 20 TO 25 KNOTS
BY LATE MORNING.
FOR TONIGHT...THE COLD FRONT WILL EVENTUALLY WASH OUT OVER THE AREA.
A MIX OF MID AND HIGH LEVEL CLOUDS CAN BE EXPECTED ALONG WITH
DIMINISHING WINDS.
LOW PRESSURE IS FORECAST TO MOVE FROM THE CENTRAL PLAINS TO THE
OHIO VALLEY ON FRIDAY. THIS SYSTEM WILL BRING THE NEXT CHANCE OF
SHOWERS...POSSIBLY A THUNDERSTORM...FROM LATE FRIDAY AFTERNOON
INTO FRIDAY NIGHT.
.OUTLOOK...MVFR CEILINGS AND VISIBILITIES POSSIBLE LATE FRIDAY
AFTERNOON INTO SATURDAY MORNING. WEST TO NORTHWEST WIND GUSTS
UP TO 30 KNOTS POSSIBLE SATURDAY AFTERNOON AND EVENING IN
ASSOCIATION WITH A COLD FRONT.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...HATZOS
LONG TERM...FRANKS
AVIATION...HICKMAN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
740 AM EDT THU SEP 20 2012
.SYNOPSIS...
A DEEPENING UPPER TROUGH OVR THE GRT LKS WILL PUSH A COLD FRONT
THROUGH CENTRAL PA LATE SATURDAY. THE UPPER TROUGH WILL ROTATE
THROUGH THE REGION SUNDAY...FOLLOWED BY HIGH PRESSURE EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
EARLY AM MODIS 11-3.7UM IMAGERY SHOWING DENDRITIC PATTERN OF FOG
IN THE VALLEYS...THE RESULT OF A COOL...CALM MORNING AND RELATIVELY
WARM RIVER/STREAM WATERS. LATEST 3KM HRRR SFC RH FIELDS SUGGEST
THE MOST PERSISTENT FOG WILL BE UNDER SFC RIDGE AXIS ACROSS THE
SUSQ VALLEY...WHERE PATCHES COULD LINGER UNTIL 14Z-15Z.
LG SCALE SUBSIDENCE AND DRY AIR ASSOCIATED WITH HIGH PRESSURE SYSTEM
WILL PROVIDE THE AREA WITH ABUNDANT SUNSHINE LATER TODAY. GEFS 8H
TEMPS SHOW MODERATION OF THIS ONCE CHILLY AIR MASS WITH MEAN 8H
TEMPS NR 9C BY AFTN...SUPPORTIVE OF HIGHS IN THE U60S AND L70S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
DYING COLD FRONT...CURRENTLY OVR MICHIGAN...WILL PUSH INTO WESTERN
PA TONIGHT...ACCOMPANIED BY AN INCREASE IN CLOUDS...BUT LITTLE IF
ANY PRECIP. WILL RAMP UP POPS TO ARND 15 PCT OVERNIGHT ACROSS THE
W MTNS WITH ARRIVAL OF THIS WEAK FRONT. HOWEVER...NEARLY ALL THE LG
SCALE FORCING REMAINS WEST OF PA ASSOC WITH DEEPENING UPPER TROUGH...SO
THE CHANCE OF ANY -SHRA WILL BE MINIMAL. SOUTHERLY FLOW AHEAD OF
THIS BOUNDARY WILL DRAW HIGHER HUMIDITY BACK INTO THE REGION...RESULTING
IN A MUCH MILDER NIGHT...WITH MINS MOSTLY ARND 50F.
DYING COLD FRONT WILL WASH OUT OVR CENTRAL PA ON FRIDAY...PROVIDING
THE FOCUS FOR SCT AFTN -SHRA. WILL PLACE AXIS OF HIGHEST POPS
/ARND 30 PCT/ ACROSS THE CENTRAL COUNTIES...WHERE MDL DATA SHOWS
TONGUE OF HIGHER SFC-8H THTE.
DESPITE A PT-MOCLDY SKY...TEMPS SHOULD REACH NR SEASONAL NORMS
FRI AFTN DUE TO WARMER RETURN SOUTHERLY FLOW AS SFC RIDGE PASSES
OFF THE COAST.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
LITTLE SPREAD AMONG MED RANGE GUIDANCE WITH RESPECT TO THE LG
SCALE PATTERN OVR THE NORTHEAST CONUS THIS WEEKEND. ALL GUIDANCE
INDICATING UPPER LOW OVR ONTARIO GRADUALLY SHIFTS EAST...PUSHING A
COLD FRONT THRU CENTRAL PA LATER SAT OR SAT NIGHT. AS MDL DATA HAS
COME INTO LINE W/REGARDS TO TIMING OF FRONT...HAVE BUMPED POPS UP
TO LIKELY FOR SAT PM. MDL DATA HINTING THAT ENOUGH HEATING/DESTABILIZATION
WILL OCCUR AHEAD OF FROPA FOR MENTION OF THUNDER IN ADDITION TO
THE SHOWERS. SOME UNCERTAINTY W/REGARDS TO AMT OF PRE-FRONTAL
CLOUD COVER AND RESULTING CAPES. HOWEVER...STRONG DEEP LYR
SHEAR...COMBINED WITH EVEN MARGINAL INSTABILITY...COULD POSE THE
THREAT OF SVR WX OVR ROUGHLY THE EASTERN HALF OF THE STATE SAT
AFTN.
AS THE UPPER TROF AXIS CROSSES THE REGION ON SUNDAY...ADDITIONAL
SHOWERS ARE POSSIBLE ACROSS MAINLY WESTERN AND NORTHERN SECTIONS.
A RATHER TIGHT PRES GRADIENT WILL PRODUCE GUSTY W WIND ACROSS THE
REGION...ACCENTUATING THE POST-FRONT CHILL. GEFS MEAN 8H TEMPS
SUPPORT HIGHS FROM THE M50S NW MTNS TO THE U60S SE.
FAIR BUT STILL COOL WEATHER APPEAR LIKELY EARLY NEXT WEEK AS
UPPER TROUGH BEGINS TO LIFT OUT AND SFC HIGH PRES BUILDS EAST
ACROSS THE OHIO VALLEY. GEFS AND ECMWF MEAN 8H TEMPS REMAIN BLW
SEASONAL NORMS BOTH MON AND TUE. SFC HIGH PRES SYS WILL PASS OFF THE
MID ATLANTIC COAST BY MID WEEK...ALLOWING A MILDER SW FLOW TO
DEVELOP.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
HIGH PRESSURE WILL REMAIN SITUATED OVER THE REGION THROUGH TONIGHT.
VALLEY FOG EARLY ON THIS CHILLY MORNING CONFINED MAINLY NORTH OF
INTERSTATE 80 /IMPACTING KUNV-KIPT-KSEG. THE FOG WILL DISSIPATE
QUICKLY AFTER 12-13Z - BRINGING A VFR DAY FOR ALL OF CENTRAL PA
WITH ONLY SOME MID/HIGH CLOUDS STREAMING OVERHEAD. SURFACE WINDS
WILL PICK UP FROM THE SOUTH...INCREASING TO 10 MPH WITH GUSTS
APPROACHING 20 MPH MAINLY ACROSS THE WESTERN HIGHER TERRAIN.
TONIGHT...WINDS BECOME LIGHT AGAIN. MID CLOUD DECK WILL THICKEN A
BIT ACROSS THE WEST...BUT VFR WILL AGAIN PREVAIL EXCEPT FOR SOME
VALLEY FOG AGAIN TOWARD SUNRISE FRI.
OUTLOOK...
FRI...MAINLY VFR. ISOLATED SHOWERS COULD PRODUCE LOCAL MVFR
CONDITIONS.
SAT...MAINLY VFR BUT A PERIOD OF MVFR CONDITIONS POSSIBLE
IN LIKELY SHOWERS.
SUN...MAINLY VFR BUT MVFR CONDITIONS POSSIBLE ACROSS THE
HIGHER MTNS.
MON...VFR...AS HIGH BUILDS ACROSS THE REGION.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
FROST ADVISORY UNTIL 9 AM EDT THIS MORNING FOR PAZ005-006-010-
011.
&&
$$
SYNOPSIS...FITZGERALD
NEAR TERM...FITZGERALD
SHORT TERM...FITZGERALD
LONG TERM...FITZGERALD
AVIATION...RXR
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
620 AM CDT THU SEP 20 2012
.AVIATION...
ONLY CONCERN THIS MORNING IS THE IFR STRATUS EXPANDING SLOWLY OVER
THE TX HILL COUNTRY AND WHETHER IT WILL WACO BEFORE 15Z. LOOK AT
KGRK VWP AND LEDBETTER PROFILER SHOW VEERED WSW FLOW 10-15 KTS IN
THE LOWEST 1-2 KFT. FEELING IS THE BULK OF STRATUS WILL REMAIN
SOUTH OF WACO...DESPITE RUC OPS40 AND GFS BUFR SOUNDINGS INDICATING
A BRIEF POTENTIAL BETWEEN 13-14Z. PER COORD WITH CWSU AND VEERED
LOW LEVEL FLOW...WILL ONLY INTRODUCE SCT009 AT WACO AND MONITOR
CLOSELY THE NEXT SEVERAL HOURS.
OTHERWISE...ALL N TX AIRPORTS WILL BE VFR THROUGH 30 HRS WITH
SCATTERED CIRRUS EXPECTED WITH NW FLOW OVERHEAD. BOUNDARY LAYER
APPEARS TOO DRY AND MIXED BY 12Z FRI FOR ANY STRATUS CONCERNS.
SOUTH FLOW AROUND 10 KTS IS EXPECTED THROUGH TONIGHT.
05/
&&
.PREV DISCUSSION... /ISSUED 305 AM CDT THU SEP 20 2012/
UPPER RIDGE AXIS REMAINS OVER THE GREAT BASIN THIS MORNING. IT
WILL SLOWLY MOVE EAST AND WEAKEN AS AN UPPER LOW MOVES INTO THE
WESTERN U.S. FROM THE PACIFIC. CANADIAN AIR IS BEING PULLED SOUTH
ACROSS THE CENTRAL PLAINS ALONG THE BACK SIDE OF THE RIDGE...BUT
BY THE TIME IT GETS THIS FAR SOUTH IT WILL BE HIGHLY MODIFIED.
I SEE NO MAJOR CHANGES TO OUR FORECAST THROUGH SATURDAY. THE
SUNDAY COLD FRONT NOW LOOKS WEAKER. THE GFS ACTUALLY STALLS THE
FRONT NEAR THE RED RIVER BUT IT IS AN OUTLIER SO HAVE GONE WITH
ECMWF/GEM/CMC SOLUTION WHICH BRINGS THE FRONT THROUGH OUR AREA
BUT IT IS WEAKER THAN PREVIOUS FORECASTS. I HAVE RAISED SUNDAY
HIGHS A BIT MORE SINCE THE FRONT IS SO WEAK...AND IF THE GFS IS
ACTUALLY CORRECT SUNDAY COULD SEE HIGHS IN THE 90S. THE REST OF
THE FORECAST WEEK LOOKS DRY AND WARM. 84
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 93 66 95 66 90 / 0 0 5 5 10
WACO, TX 91 62 92 63 92 / 0 0 5 5 10
PARIS, TX 90 59 93 62 92 / 0 0 5 5 10
DENTON, TX 94 64 94 63 89 / 0 0 5 5 10
MCKINNEY, TX 93 61 95 61 92 / 0 0 5 5 10
DALLAS, TX 93 66 95 67 91 / 0 0 5 5 10
TERRELL, TX 92 61 93 63 91 / 0 0 5 5 10
CORSICANA, TX 91 62 92 64 93 / 0 0 5 5 10
TEMPLE, TX 91 61 91 62 92 / 0 0 5 5 10
MINERAL WELLS, TX 93 60 93 61 89 / 0 0 5 5 10
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
05/84
AREA FORECAST DISCUSSION
NWS SACRAMENTO CA
916 AM PDT THU SEP 20 2012
.SHORT TERM DISCUSSION...
A LOOK OVER CURRENT FORECAST AND MODELS SEEMS THAT FORECAST IS IN
REALLY GOOD SHAPE. THE BIGGEST CHALLENGE FOR THIS PACKAGE WILL BE
THE UPPER LOW PROGGED TO SLIDE SOUTH INTO AREA SATURDAY NIGHT AND
SUNDAY. AT THIS TIME...PRETTY GOOD AGREEMENT THAT THE MAIN IMPACTS
OF THIS UPPER LOW SHOULD REMAIN OUT OF OUR AREA...BUT TREND THIS
SUMMER FOR SYSTEMS LIKE THIS HAVE BEEN TO SLIDE A BIT FURTHER WEST
THAN MODELS EXPECT. IF THIS WHERE TO HAPPEN SHOWER AND
THUNDERSTORMS CHANCE WOULD HAVE BE INCREASED IN AREAL COVERAGE A
BIT TO THE WEST. CURRENT FORECAST DOES ALLOW FOR SOME ERROR IN A
WESTERN LOCATION. WILL SEE HOW NEW ECMWF AND GFS LINE UP WITH
MORNING NAM FOR AFTERNOON PACKAGE...BUT RIGHT NOW...NO UPDATES
NEEDED FOR MORNING UPDATE. RASCH
.EXTENDED DISCUSSION (MONDAY THROUGH THURSDAY)
BY MONDAY AFTERNOON...ALL MODELS NOW MOVE UPPER LOW CENTER INTO
THE GREAT BASIN. HAVE REDUCED THREAT OF THUNDERSTORMS OVER SIERRA
FOR MONDAY BUT RAP AROUND ACTIVITY COULD SPARK SOME ISOLATED
THUNDERSTORMS OVER THE CREST. MODELS DIVERGE SOMEWHAT BY NEXT
TUESDAY IN DEALING WITH ANOTHER WEAK PACIFIC TROUGH FORECAST TO
MOVE ONTO THE NORCAL COAST. AT THIS TIME...IT APPEARS THIS SYSTEM
WILL BE TOO WEAK TO PRODUCE A SIGNIFICANT THREAT OF SHOWERS OR
THUNDERSTORMS. GFS MOVES THIS LOW QUICKLY THROUGH NORCAL ON
WEDNESDAY WHILE GEM AND ECMWF DROP THE TROUGH SOUTHWARD FORMING A
CLOSED LOW SOMEWHERE ALONG THE CENTRAL CALIFORNIA COAST. GEM/ECMWF
SOLUTION WOULD BRING A THREAT OF SHOWERS OR THUNDERSTORMS TO THE
SIERRA CASCADE CREST WHILE GFS WOULD KEEP FORECAST AREA DRY ON
WEDNESDAY. WILL KEEP SLIGHT THREAT OF THUNDERSTORMS IN FOR THE
SIERRA CASCADE RANGE ON WEDNESDAY AND THURSDAY FORECAST PERIOD
UNTIL MODELS COME INTO BETTER ALIGNMENT. OTHERWISE MAINLY FAIR
SKIES CONTINUE WITH NEAR NORMAL TEMPERATURES.
&&
.AVIATION...VFR CONDITIONS EXPECTED NEXT 24 HOURS EXCEPT
POSSIBLE MVFR CONDITIONS WITH PATCHY LOW CLOUDS IN THE DELTA
REGION WEST OF KSUU THROUGH 16Z. SOUTHWEST WINDS UP TO 20 KTS IN
THE DELTA...WITH TAF SITES GENERALLY LESS THAN 12 KTS. -DVC
&&
.STO WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
627 PM EDT THU SEP 20 2012
.SYNOPSIS...
A WEAK COLD FRONT WILL PUSH EAST OF THE AREA TONIGHT. LOW PRESSURE
WILL MOVE ACROSS THE CENTRAL LAKES EARLY SATURDAY DRAGGING A STRONG
COLD FRONT ACROSS THE AREA.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
AT WHAT POINT DOES ONE GIVE UP BELIEVING THE HRRR. IT HAS CONTINUED
TO SHOW QUITE A BIT OF WEAK CONVECTIVE LOOKING PRECIP SINCE EARLIER
THIS AFTERNOON FOR THE PERIOD 19Z THRU ABOUT 03Z. SO FAR NOTHING
MUCH HAS HAPPENED. RUC WITH CONSIDERABLY LESS PRECIP AND SO FAR
SEEMS TO BE VERIFYING BETTER. WON`T TOTALLY GIVE UP ON PRECIP FOR
THE FIRST HALF OF THE NIGHT BUT HAVE TRIMMED BACK POPS SOME MORE.
MORE CLOUDS HAVE FILLED IN WEST OF THE AREA SO WONDER HOW MUCH
CLEARING WILL BE ABLE TO TAKE PLACE IN THIS AREA. HAVE NOT ADJUSTED
TEMPS YET AS WE AREA CURRENTLY ALREADY GOING 3 TO 5 DEG WARMER THAN
SURROUNDING FORECASTS.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY NIGHT/...
MODELS STILL NOT IN TOTAL AGREEMENT ON THE TRACK AND TIMING OF THE
NEXT COLD FRONT THAT WILL MOVE ACROSS THE AREA FRIDAY NIGHT INTO
SATURDAY MORNING. NAM STILL THE FASTEST OF THE 3 MODELS. BASICALLY
RAIN WILL DEVELOP FROM THE WEST TOMORROW EVENING AND MOVE ACROSS THE
AREA FRIDAY NIGHT. COULD SEE A FEW LINGERING SHOWERS IN THE EAST
SATURDAY MORNING...BUT MOST OF AREA WILL SEE LULL SATURDAY MORNING.
THEN SECONDARY TROUGH FORECAST TO ROTATE ACROSS THE AREA SATURDAY
AFTERNOON INTO SATURDAY NIGHT. BY 12Z SUNDAY 850 TEMPS DIP TO 0C
SETTING UP POTENTIAL FOR SOME LAKE EFFECT SHOWERS IN THE SNOWBELT
EAST OF CLEVELAND.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
THE LONG TERM PORTION BEGINS ON MONDAY WITH THE GFS AND ECMWF
SIMILAR. BOTH SHOW HIGH SURFACE PRESSURE ACROSS THE TENNESSEE AND
LOWER OHIO VALLEY AND AN UPPER LOW OVER HUDSON BAY. 850MB TEMPS
ACROSS THE AREA ALSO SIMILAR AT 2 TO 4C. GFS HOWEVER SHOWS DRY AIR
ACROSS THE AREA WHILE THE ECMWF IS A BIT MORE MOIST WITH MORE OF A
NORTHWEST FLOW ALOFT. GIVEN THE DIFFERENCE WILL SIDE WITH THE NEWER
GFS. WILL HAVE A SLIGHT CHANCE OF A SHOWER IN THE SNOW BELT
COUNTIES BUT WITH THE DRY AIR IN PLACE...NOT LOOKING FOR MUCH.
TUESDAY MODELS COME MORE INTO PHASE WITH THE UPPER TROF NOW
EXTENDING AVER THE GREAT LAKES AND THE SURFACE HIGH NOW MOVING OFF
THE MID ATLANTIC COAST. THE GFS HOWEVER SHOWS AN EMBEDDED SHORT WAVE
WITH ASSOCIATED MOISTURE MOVING ACROSS THE AREA DURING THE DAY WHILE
THE ECMWF DOES NOT SHOW THIS. WILL SIDE MORE TOWARD THE DRIER ECMWF
GIVEN EVERYTHING ELSE IS FAIRLY CLOSE. THE MODELS DO SHOW WARMER AIR
MOVING INTO THE AREA WHICH WOULD FAVOR MORE OF A PARTLY SUNNY DAY VS
CLOUDS. WEDNESDAY A SHORT WAVE RIDGE WILL BE MOVING ACROSS WESTERN
ONTARIO KICKING THE UPPER TROF FURTHER EAST ACROSS THE GREAT LAKES.
MODELS START TO DIFFER AGAIN WITH THE GFS TAKING A COLD FRONT SOUTH
ACROSS THE REGION WHILE THE ECMWF IS MUCH SLOWER. WILL SIDE HERE
WITH THE GFS AGAIN AND BRING THE FRONT THROUGH GIVEN THE SIZE AND
POSITION OF THE SURFACE HIGH TO OUR NORTH.
&&
.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
MIDDLE AND HIGH LEVEL CLOUDS NOW COVERING MOST OF THE FORECAST
AREA. SOME SCATTERED SHOWERS AND A FEW EMBEDDED THUNDERSTORMS HAVE
BEEN ASSOCIATED WITH THIS WEAK FRONTAL SYSTEM MOVING EASTWARD
ACROSS WESTERN OHIO AND SOUTHERN CANADA.
THESE SHOWERS WILL ATTEMPT TO MOVE EASTWARD BUT DEWPOINTS REMAIN
REMAIN IN THE 40S AT SEVERAL SITES IN CENTRAL AND EASTERN OHIO.
WILL MENTION A FEW SHOWERS AND USE VCSH AT A COUPLE SITES.
SOUTHWEST WINDS 10 TO 15 KNOTS WITH GUSTS TO 20 TO 25 THIS
AFTERNOON THEN DIMINISHING BEHIND THE WEAK FRONTAL SYSTEM.
.OUTLOOK...AREAS OF NON VFR IN SHOWERS FRI AFTERNOON THROUGH
SATURDAY NIGHT.
&&
.MARINE...
LAKE REMAINS CHOPPY WITH A SSW FLOW. HAVE ALLOWED THE WEST END SMALL
CRAFT TO EXPIRE WITH SUSTAINED WIND SPEEDS UNDER 22 KNOTS. THINK THE
2 TO 4 FEET WILL HOLD ACROSS THE EAST END AS WE ARE EXPECTING A
SUBTLE WIND SHIFT THIS EVENING BUT WINDS RELAXING SOME. IN GENERAL
SOUTHWEST FLOW CONTINUES WITH UPPER TROUGH/CYCLONIC FLOW ACROSS THE
NORTHERN AND CENTRAL LAKES FROM FRIDAY INTO SATURDAY. BETWEEN THOSE
TWO DAYS THERE WILL BE SLIGHT FLUCTUATIONS IN THE WIND DIRECTION WITH
WEAK DISTURBANCES MOVING ACROSS. BY SATURDAY NIGHT THE UPPER TROUGH
SWINGS ACROSS THE EASTERN LAKES AND THE WEST-NORTHWEST FLOW
INCREASES. IT IS UNCERTAIN HOW STRONG WINDS MAY BE WITH ONE MODEL
HINTING AT GALES AND ANOTHER MUCH LESS. FOR NOW WILL STICK AT 20-25
KNOTS. SMALL CRAFT ADVISORY POSSIBLE SATURDAY AND LIKELY SUNDAY. IT
WILL NOT TAKE MUCH TO KICK UP THE LAKE THIS TIME OF YEAR. HIGH
PRESSURE BUILDS ACROSS THE LAKE EARLY NEXT WEEK.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...DJB
NEAR TERM...DJB/ADAMS
SHORT TERM...DJB
LONG TERM...TK
AVIATION...BC
MARINE...OUDEMAN
AREA FORECAST DISCUSSION
NWS AMARILLO TX
344 PM CDT THU SEP 20 2012
.DISCUSSION...
A STRONG UPPER LOW OVER HUDSON BAY ALONG WITH AN AMPLIFIED RIDGE
ACROSS THE WESTERN CONUS IS MAINTAINING NORTHWEST FLOW ALOFT ACROSS
THE PANHANDLES. A SUBTLE SHORTWAVE TROUGH WILL MOVE OUT OF THE
ROCKIES AND ACROSS THE TEXAS PANHANDLE TONIGHT. A DRY AIR MASS
REMAINS ACROSS THE AREA WITH DEWPOINTS ONLY IN THE UPPER 30S TO THE
MID 40S. HOWEVER DESPITE THIS LACK OF SUBSTANTIAL MOISTURE...HAVE
LEFT IN MENTION OF ISOLATED THUNDERSTORMS IN THE EASTERN TEXAS
PANHANDLE WHERE LIFT FROM THIS SHORTWAVE CAN INTERACT WITH SLIGHTLY
HIGHER MOISTURE VALUES. SPC RUC MESOSCALE ANALYSIS SHOWS SOME
INSTABILITY IN THIS AREA WITH SBCAPES AROUND 1500 J/KG. HOWEVER A
FAIRLY STRONG CAP ALSO EXISTS IN THIS AREA SO THUNDER DEVELOPMENT
LOOKS PRETTY SLIM. LOWS TONIGHT WILL BE SLIGHTLY WARMER WITH LOWS
RANGING FROM THE UPPER 40S IN THE WESTERN OKLAHOMA PANHANDLE TO
NEAR 60 DEGREES IN THE SOUTHEAST TEXAS PANHANDLE.
A COLD FRONT WILL PUSH SOUTH ACROSS THE PANHANDLES FRIDAY. CAN SEE A
PERIOD OF GUSTY WINDS INITIALLY BEHIND THE FRONT ALTHOUGH WINDS
WILL DIMINISH DURING THE DAY AS SURFACE HIGH PRESSURE BUILDS ACROSS
THE CENTRAL PLAINS. GIVEN THE NORTHERLY FETCH...HAVE LEANED TOWARD
THE COOLER MAV GUIDANCE WITH HIGH TEMPS IN THE 80S TO THE LOWER 90S
IN THE FAR SOUTHEAST TEXAS PANHANDLE.
THE WESTERN CONUS UPPER RIDGE WILL SLIDE TO THE EAST OVER THE
WEEKEND WHERE IT WILL FLATTEN EARLY NEXT WEEK IN RESPONSE TO AN
UPPER LOW MOVING ACROSS THE GREAT BASIN. ALTHOUGH THE FIRST DAY OF
FALL IS SATURDAY...TEMPERATURES WILL BE MORE SUMMER-LIKE OVER THE
WEEKEND AND EARLY NEXT WEEK DUE TO SOUTHERLY WINDS AND RISING
HEIGHTS. MEDIUM RANGE MODELS ARE COMING INTO BETTER AGREEMENT WITH
THE UPPER LOW AS IT MOVES ACROSS THE CENTRAL PLAINS MID WEEK. THE
FLOW ALOFT WILL TRANSITION TO THE SOUTHWEST ALLOWING FOR THE
TRANSPORT OF MOISTURE ACROSS THE AREA. THIS LOW CAN TAP INTO THIS
MOISTURE AND BRING THE NEXT CHANCE OF RAIN TO THE AREA BY AROUND
THURSDAY. HOWEVER SINCE THIS IS STILL QUITE AWAYS OFF INTO THE
FUTURE HAVE OPTED TO KEEP THE INHERITED DRY FORECAST INTACT.
CLK
&&
.FIRE WEATHER...
AFTERNOON RELATIVE HUMIDITY VALUES CAN DROP TO AROUND 20 PERCENT
ACROSS THE OKLAHOMA PANHANDLE AND THE NORTHERN TEXAS PANHANDLE
FRIDAY. HOWEVER 20 FOOT WINDS ARE EXPECTED TO STAY BELOW 15
MPH...PRECLUDING ELEVATED AND CRITICAL FIRE WEATHER CONDITIONS. A
WIND SHIFT TO THE NORTH WILL OCCUR FRIDAY AS A COLD FRONT
DROPS SOUTH ACROSS THE AREA. GUSTY WINDS CAN ALSO DEVELOP
BEHIND THIS FRONT BUT WILL DIMINISH LATER IN THE DAY. SLIGHTLY COOLER
AIR BEHIND THIS FRONT WILL SPREAD ACROSS THE AREA SATURDAY WHICH WILL
LEAD TO MINIMUM RELATIVE HUMIDITIES TO STAY ABOVE 20 PERCENT.
UNSEASONABLY WARM TEMPERATURES WILL RESULT IN RELATIVE HUMIDITY
VALUES TO FALL TO AROUND 15 TO 20 PERCENT IN THE WESTERN OKLAHOMA
PANHANDLE AND THE NORTHWEST TEXAS PANHANDLE SUNDAY AND MONDAY.
HOWEVER 20 FOOT WINDS ARE EXPECTED TO BE BELOW 15 MPH...PRECLUDING
ELEVATED AND CRITICAL FIRE WEATHER CONDITIONS. RELATIVE HUMIDITIES
SHOULD STAY NEAR OR ABOVE 20 PERCENT AFTER MONDAY AND WHILE 20 FOOT
WINDS FOR THE MOST PART WILL STAY BELOW 15 MPH...THEY CAN INCREASE TO
AROUND 15 TO 20 PERCENT AT TIMES. HOWEVER THE STRONGER WINDS ARE
EXPECTED TO OCCUR WHERE RELATIVE HUMIDITY VALUES WILL BE ABOVE
CRITICAL THRESHOLDS. THE CHANCE FOR WETTING RAINS IS SLIM THROUGH THE
NEXT SEVEN DAYS.
CLK
&&
.PRELIMINARY POINT TEMPS/POPS...
AMARILLO TX 58 84 55 84 54 / 5 0 0 5 5
BEAVER OK 54 88 54 83 50 / 5 0 5 5 10
BOISE CITY OK 50 84 49 83 52 / 0 5 5 10 5
BORGER TX 60 88 60 87 57 / 5 0 0 5 10
BOYS RANCH TX 51 86 53 88 53 / 0 0 0 5 5
CANYON TX 55 85 54 84 51 / 5 0 0 5 5
CLARENDON TX 60 87 58 86 56 / 10 5 0 5 10
DALHART TX 50 84 52 83 49 / 0 0 0 10 5
GUYMON OK 54 87 53 84 50 / 5 0 5 5 10
HEREFORD TX 52 85 53 85 51 / 5 5 0 5 5
LIPSCOMB TX 56 87 53 85 50 / 10 5 5 5 10
PAMPA TX 58 84 56 83 53 / 10 5 0 5 10
SHAMROCK TX 59 89 57 86 53 / 10 5 0 5 10
WELLINGTON TX 59 93 58 90 54 / 10 5 0 5 10
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
OK...NONE.
&&
$$
09/05