-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KBGM 152332
AFDBGM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BINGHAMTON NY
732 PM EDT WED MAY 15 2013

.SYNOPSIS...
A COLD FRONT WILL SLIDE THROUGH THE REGION THIS AFTERNOON WITH
ONLY A SLIGHT CHANCE OF THUNDERSTORMS. THE FRONT WILL QUICKLY EXIT
THIS EVENING...LEAVING MAINLY DRY WEATHER THURSDAY AND FRIDAY.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
-- Changed Discussion --
725 PM UPDATE...
QUICK UPDATE TO REMOVE MENTION OF ALL THUNDER AS COLD FRONT WHICH
NOW JUST MOVED THROUGH THE BGM AIRFIELD CONTINUES TO PRODUCE
LITTLE TO NO SIGNS OF DEVELOPING SHWRS OR STORMS. BEHIND THIS
FRONT...WINDS REMAIN RATHER GUSTY AS PRESSURE RISE COUPLET OF
2-3 MB/HR MOVES OVER THE REGION WITH SEVERAL STATIONS REPORTING
GUSTS TO TO NEAR 30 KTS. ASIDE FROM SOME MINOR TEMP/DEWPOINT
ADJUSTMENTS...FCST REMAINS IN GOOD SHAPE THIS HR AND NO ADDITIONAL
CHANGES NEED.

345 PM UPDATE...
IT APPEARS ELEVATED MIXED LAYER AS DEPICTED BY 7.4 MICRON IMAGERY
HAS SIMPLY BEEN TOO MUCH TO OVERCOME. DETROIT 12Z SOUNDING THIS
MORNING INDICATED A CONVECTIVE INITIATION TEMPERATURE IN THE 90S.
THAT AIR IS NOW INJECTING ITSELF OVER OUR REGION. SO DESPITE
INSTABILITY IN A GOOD PORTION OF OUR COLUMN...DRY MID LEVELS AND
DEWPOINTS ONLY IN THE UPPER 40S TO LOW 50S IS NOT ENOUGH TO
OVERCOME CAP BENEATH THE ELEVATED MIXED LAYER. TEMPERATURES ARE
EVEN IN UPPER 70S TO NEAR 80 IN THE WESTERN ZONES AND IT IS STILL
NOT ENOUGH. I BACKED WAY OFF ON POPS TO ONLY SLIGHT CHANCE FOR
SHOWERS/THUNDER LATE AFTERNOON-EARLY EVENING ALONG THE COLD FRONT
AND ALSO TOUCHED UP SKY AND TEMPERATURE GRIDS TO REFLECT THE NEW
REALITY.

PREVIOUS DISCUSSION FROM 130 PM...
WARM FRONT IS JUST FINISHING ITS PASSAGE THROUGH THE AREA. IT WAS
ACCOMPANIED BY MAINLY LIGHT SHOWERS BUT ALSO SOME ELEVATED
THUNDERSTORMS WHICH PRODUCED A FEW REPORTS OF SMALL HAIL IN THE
LAKE PLAIN TO MOHAWK VALLEY AREAS.

THOUGH WE HAD AT LEAST SOME WEAK UPPER SUPPORT EARLIER...IT
CONTINUES TO DIMINISH AS WE GET OVERTAKEN BY THE RIGHT EXIT REGION
/SUBSIDENCE INFLUENCE/ OF THE LARGER MAIN JET MAXIMUM THAT IS
PROGRESSING FROM THE NORTHERN GREAT LAKES TO ONTARIO. ALSO...WHAT
HAS BECOME VERY APPARENT ON 7.4 MICRON IMAGERY IS ELEVATED DRY
MIXED LAYER PUNCHING IN FROM THE WEST BEHIND THE WARM FRONT. WHILE
THIS IS YIELDED THE STEEP MID LEVEL LAPSE RATES THAT ALLOWED FOR A
FEW STRONGER STORM CELLS EARLIER...IT WILL ALSO HAVE DETRIMENTAL
EFFECT ON CONVECTION THIS AFTERNOON ALONG THE COLD FRONT BECAUSE OF
MID LEVEL CAPPING AND LOWERING PRECIPITABLE WATER LIMITING
COVERAGE. THAT BEING SAID...QUICK WARMING IS NOW OCCURRING IN THE
FAIRLY SUNNY WARM SECTOR AND THUS SURFACE-BASED DESTABILIZATION.

WHILE WE STILL NEED MONITOR THINGS DUE TO THE HIGH AMOUNT OF SHEAR
AND THUS GUSTY WIND THREAT...OVERALL THREAT APPEARS TO BE LIMITED
AND ISOLATED. ATTEMPTED SURFACE-BASED CONVECTIVE DEVELOPMENT WILL
OCCUR ALONG COLD FRONT THIS AFTERNOON...WITH INCREASING YET STILL
ONLY SCATTERED COVERAGE AS IT HEADS SOUTH AND EAST /AND WHERE IT
OCCURS...A GUSTY WIND THREAT/. HOWEVER...THE GAPPY COVERAGE OF
INITIALIZING CONVECTION MEANS THAT MUCH OF THE AREA MAY ALREADY BE
DONE WITH RAINFALL...AND EVEN WHERE IT DOES OCCUR THE SPEED OF THE
SYSTEM AND LOWERING PRECIPITABLE WATER WILL GREATLY LIMIT AMOUNTS
TO LESS THAN A QUARTER INCH. BETTER CONVECTION CHANCES LOOK TO BE
MAINLY SOUTH OF OUR AREA...WHERE DEWPOINTS WILL REACH UPPER
50S/LOW 60S INSTEAD OF MAINLY LOW 50S.

FRONT AND ASSOCIATED SCATTERED CONVECTION QUICKLY EXIT THIS
EVENING...WITH CLEARING SKY OVERNIGHT. LOWS RANGING FROM 40S TO
NEAR 50...AS FAIR AMOUNT OF MIXING FOR MOST OF THE NIGHT SHOULD
LIMIT AMOUNT OF RADIATIONAL COOLING.
-- End Changed Discussion --

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
300 PM UPDATE...
BRISK FLATTENED CYCLONIC UPPER FLOW THURSDAY. THAT ALONG WITH
SUNSHINE PROMOTING STEEP LAPSE RATES SHOULD ALLOW MIXING ALL THE
WAY TO 700-600MB AND SO FAIRLY GUSTY WINDS WILL MANAGE TO MIX
DOWN. EXPECTING FREQUENT 15-25 MPH GUSTS IN NEPA AND 25-35 MPH IN
CENTRAL NY. INVERTED-V LOWER SOUNDING...IN ADDITION TO YIELDING
GUSTY WINDS...ALSO SUGGESTS THE MODEL GUIDANCE WILL BE NOT HAVE
LOW ENOUGH DEWPOINTS AS IS TYPICALLY THE CASE IN THESE SITUATIONS.
THUS DESPITE SLIGHTLY LOWER THICKNESSES...WITH WIDE SPREAD BETWEEN
TEMPERATURE AND DEWPOINT...I DO NOT ANTICIPATE ANY PROBLEM REALIZING
FAIRLY WARM MAXIMUM TEMPERATURES THURSDAY MAINLY IN THE 70S.
RELATIVE HUMIDITY LEVELS WILL ALSO REACH IN THE UPPER 20S/LOW 30S
PERCENT RANGE...PERHAPS EVEN SLIGHTLY LOWER IN PORTIONS OF NEPA.

SECONDARY FRONT DROPS THROUGH LATE THURSDAY. THE ASSOCIATED
ADDITIONAL COLD AIR ADVECTION WILL KNOCK TEMPERATURES DOWN
SLIGHTLY TO AROUND CLIMATOLOGY FRIDAY...YET STILL A DRY PLEASANT
DAY AND THIS TIME WITH LIGHTER WINDS.

QUIET BOTH THURSDAY NIGHT AND FRIDAY NIGHT WITH LOWS MAINLY IN THE
40S. HOWEVER...WITH HIGH PRESSURE BUILDING IN FRIDAY...THERE MAY
BE GOOD RADIATIONAL COOLING FRIDAY NIGHT ESPECIALLY NORTHEAST AWAY
FROM POTENTIAL INCREASE IN HIGH CLOUDS. SO I WOULD NOT BE
SURPRISED IF SOME OF THE TYPICAL COLD DRAINAGE SPOTS/SHELTERED
VALLEYS FOUND THEIR WAY INTO THE UPPER 30S.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
MODEL AGREEMENT THROUGH THE EXTENDED TIMEFRAME REMAINS LESS THAN
STELLAR THIS AFTERNOON WITH BOTH DETERMINISTIC LONG RANGE MODELS
DISAGREEING ON THE ARRIVAL TIMING OF NEXT WEEK/S UPPER RIDGE. MAIN
PROBLEM REMAINS UPPER BLOCKING SOUTH OF GREENLAND AND REMNANT
UPPER LOW WHICH IS NOW PASSING OFF TO OUR NORTH THIS AFTERNOON.
BOTH MODELS SHOW THIS FEATURE STALLING TO OUR EAST BY THE WEEKEND
ENSURING CYCLONIC NORTHWEST FLOW OVER OUR REGION FOR THE UPCOMING
WEEKEND. THE ECMWF REMAINS THE FASTER SOLUTION IN BRINGING DECENT
RIDGING ALOFT INTO OUR AREAS BY LATE SUN...WHILE THE GFS DELAYS
AND EVEN SUPPRESSES THE APPROACHING RIDGE WITH ITS SUGGESTION THAT
A MIDWEST UPPER LOW WILL DIG SOUTHEAST INTO THE WESTERN GREAT
LAKES. IN ANY EVENT...MAIN FRONTAL BOUNDARY LOOKS TO REMAIN
STALLED SOUTH OF THE FCST REGION THROUGH THE PERIOD WITH A GRADUAL
REDUCTION IN POPS MADE FOR THE UPCOMING WEEKEND. BEYOND
THIS...HAVE GENERALLY FOLLOWED WPC/S GUIDANCE TRENDS WHICH FAVORS A
FAIRLY DECENT WARM UP EARLY NEXT WEEK.

&&

.AVIATION /23Z WEDNESDAY THROUGH MONDAY/...
VFR MID-HI CLDS ARE EXITING CENTRAL NY/NE PA AND WERE LINGERING AT
KRME AND KAVP. REST OF TAFS WERE EITHER VFR SKC OR SOME HI CI. THERE
WERE A FEW SHRA AND EVEN AN ISLD BRIEF TSRA...WHICH HAVE EXITED
NOW. THIS ACTIVITY WAS ASSOCIATED WITH LL MOISTURE ADVECTION AND
BNDRY LAYER HEATING INCREASING THE INSTABILITY IN THE PRESENCE OF
A SMALL UPPER LEVEL WAVE WHICH WAS RIPPLING THRU THE REGION. AFTER
THIS INITIAL SHOT OF LIFTING...THE CLDS WILL CLEAR OUT DUE TO
STRG SUBSC IN THE MIDDLE LAYERS AS SEEN ON THE MODEL AND OBSERVED
SOUNDINGS. SKIES WILL CLR WITH A FEW MID OR HI CLDS AT TIMES FOR A
WHILE THIS AFTERNOON. A STRG MID-UPR LEVEL JET WILL PRESS
SOUTHWARD ON THE SOUTH SIDE OF A STRG UPR LVL PV CENTER FROM THE
UPPER LAKES AND SRN CANADA. THIS MID-UPR LEVEL JET MAX WILL BE THE
IMPETUS TO PUSH A CD FRNT THRU LATER TODAY INTO THE EVENING. THE
FRONT WON/T HAVE MUCH MOISTURE TO WORK WITH...AT LEAST AT MID
LEVELS. LL MOISTURE ADVECTION CONTINUES ALONG WITH CONTINUED BNDRY
LAYER HEATING WHICH WILL LEAD TO MIXED LAYER CAPES BETWEEN 500 AND
1000 J/KG LATER TODAY. THERE WILL BE A SUBSC INVERSION WHICH CUD
CAP THINGS OFF. THE LIFTING AT MID-UPR LEVELS WAS NOT THAT STRG
AND THE FRNT WAS NOT THAT APPARENT IN THE PRESSURE FIELDS.
ADDITIONALLY WITH STRG MID LEVEL FLOW THERE WAS TREMENDOUS SHEAR
WHICH IN THE PRESENCE OF LOW CAPE...AND WEAKER FORCING THIS
LIKELY WON/T AMOUNT TO TOO MUCH CONVECTION. AN ISLD BKN LINE OF
SHRA AND SOME TSRA LIKELY WILL FORM 20Z-24Z ACRS CWA AND MISS MOST
TAF SITES. BEST CHC FOR TSRA WILL BE AT KAVP WHERE INSTABILITY WAS
GREATER.

AFTER FRONT PASSES THRU...VFR AND MAINLY CLEAR SKIES FOR REST OF
TAF PD TIL 18Z THU.

WINDS WILL BECOME SWRLY AT 10-20 KNOTS THIS AFTERNOON AS HIGHER
MOMENTUM AIR MIXES DOWN. KBGM 88D SHOWS SW 20-30 KNOTS JUST ABV
THE LOWEST LAYER WHICH SHUD MIX DOWN THIS AFTERNOON AND INCREASE
AND VEER SFC WINDS. AFTER FROPA THIS EVE...EXPECT W-NW WINDS 5 TO
10 KNOTS...WITH 10-15 KNOTS THU AM.

OUTLOOK...

THUR PM/FRI/SAT/SUN/MON...VFR.

&&

.FIRE WEATHER...
-- Changed Discussion --
WITH MUCH OF THE AREA PROBABLY NOT RECEIVING A WETTING RAIN FROM
THE SYSTEM THIS AFTERNOON...GUSTY WESTERLY WINDS ON THURSDAY
COMBINED WITH LOW HUMIDITY VALUES COULD PRESENT FIRE SENSITIVE
CONDITIONS.
-- End Changed Discussion --

&&

.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.

&&

$$
SYNOPSIS...MDP
NEAR TERM...CMG/MDP
SHORT TERM...MDP
LONG TERM...CMG
AVIATION...DJN
FIRE WEATHER...