-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KBGM 211555
AFDBGM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BINGHAMTON NY
1155 AM EDT TUE MAY 21 2013

.SYNOPSIS...
A WARM AND HUMID WEATHER PATTERN HAS SET UP ACROSS THE AREA AND
WILL CONTINUE THROUGH THURSDAY, WITH HIGH TEMPERATURES NEAR TO
JUST ABOVE 80 AND LOWS MAINLY IN THE 60S. SCATTERED SHOWERS AND
THUNDERSTORMS CAN BE EXPECTED. A COLD FRONT WILL TRACK ACROSS THE
AREA THURSDAY NIGHT WITH SHOWERS AND THUNDERSTORMS. MUCH COOLER
WEATHER WILL FOLLOW BEHIND THE FRONT FRIDAY AND SATURDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
1100 AM UPDATE...AREA OF SCATTERED SHOWERS AND THUNDERSTORMS THAT
TRACKED ACROSS NRN CWA AT MID MORNING IS NOW OVER EASTERN NEW
YORK. THIS ACTIVITY DEVELOPED IN THE VCNTY OF A WARM FRONT ALONG
WITH A PASSING MID LEVEL SHORT WAVE. ACTIVITY HAS NOW DIMINISHED
TO A FEW ISOLATED SHOWERS IN THE LAKE PLAIN.

TEMPS LATE THIS MORNING ARE ALREADY IN THE MID 70S TO LOWER 80S
WITH 100MB MIXED LAYER CAPES AT 1000-2000 J/KG OVER THE TWIN TIERS.
AREA WILL CONTINUE TO DESTABILIZE THROUGH MID AFTERNOON WITH
CAPES APPROACHING 2500-3000 J/KG, VERY UNSTABLE. UPSTREAM
SOUNDINGS SHOW AND ELEVATED MIXED LAYER WHICH THE MODEL SOUNDINGS
INDICATE MAY ADVECT INTO CENTRAL NY THIS AFTERNOON. THE INSTABILITY
IS IN PLACE OVER THE REGION BUT WE LACK STRONG FORCING MECHANISM
OR ENOUGH DEEP LAYER SHEAR TO SUPPORT WIDESPREAD SEVERE WEATHER. A
WEAK WARM FRONT WILL REMAIN OVER NRN NY AND POSSIBLY DROP SLIGHTLY
SOUTH THIS AFTERNOON WHICH COULD HELP INITIATE CONVECTION. ANOTHER
FEATURE APPARENT ON SATELLITE IS OVER EASTERN OHIO/WESTERN PA,
THIS BOUNDARY MAY ALSO TRIGGER ACTIVITY THIS AFTERNOON, SOME OF
THE MESO SCALE MODELS INDICATING THIS SCENARIO. WILL CONTINUE
WITH INCREASING POPS THIS AFTERNOON/EVENING INTO THE HIGH CHC/LOW
LIKELY ALONG WITH THE THREAT FOR ISOLATED SEVERE WEATHER WITH
DAMAGING WINDS AND LARGE HAIL.

620 AM UPDATE...
QUICK UPDATE TO ADD POPS IN FOR THUNDER ACRS FAR NRN ZONES EARLY
THIS MRNG. NO OTHER CHGS NEEDED ATTM.

320 AM UPDATE...
WMFNT LOCATED ACRS NRN ZONES AT THIS TIME. WK WV IS RESPONSIBLE FOR
SPARKING OFF CONVECTION, MAINLY NORTH OF THE NY THRUWAY HOWEVER A
FEW PIN-PRICK STORMS ARE DEVELOPING FURTHER TO THE SOUTH.

WMFNT WL LV CWA IN WARM SECTOR FOR A TIME THIS AFTN WITH DWPTS
CLIMBING INTO THE 60S AND MAX TEMPS IN THE 80S AREA-WIDE WITH VLY
LOCALES INTO THE MID-80S. THIS WL LEAD TO INSTABILITY INCREASING
THRU THE DAY, THO HOW MUCH RMNS TO BE SEEN. 00Z NAM INDICATES CAPES
ON THE ORDER OF 2000-3000 J/KG WHILE 00Z GFS SHOWING AROUND 2000
J/KG. THIS WL BE PLENTY OF INSTABILITY TO GENERATE TSTMS, HWVR
TRIGGER WL BE LACKING UNTIL CLOSER TO 00Z WHEN WV ROUNDS THE UPR LVL
TROF.

LATEST MODELS SHOWING WMFNT SINKING BACK THRU THE AREA WHICH WUD
LKLY PROVIDE A TRIGGER FOR AFTN CONVECTION. IN ADDITION, ONGOING
CONVECTION ALONG WITH WIND SHIFT MAY LAY OUT BNDRYS DRG THE DAY TDA.
HV KEPT CHC POPS THRU A GOOD PORTION OF THE DAY WITH SCTD SHRA/TSRA
EXPECTED AND AFTER 21Z AS WV GETS CLOSER, HV INCREASED POPS TO LKLY
ACRS NRN ZONES.

POTENTIAL EXISTS FOR A STRONG TO AN ISOLD SVR STORM THIS AFTN WITH
ANYTHING THAT IS ABLE TO FORM. EXPECTING MOSTLY PULSE TSTMS TDA WITH
MEAGER WIND FIELDS.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
320 AM UPDATE...
WV WL RIDE UP ALONG THE FRONT TONIGHT ALONG WITH S/WV TOPPING THE
RIDGE. HV CONTD LKLY POPS ACRS NRN ZONES THRU 06Z TONIGHT WITH A
GRADUAL DECREASE AFT THIS TIME. CAPES RMN ELEVATED LEADING TO
THUNDER CONTG.

SHOWER AND TSTM CHCS WL CONTINUE UNTIL FROPA LATE THUR NGT. UPTICK
IN ACTIVITY DRG THE AFTN HRS AND HV BUMPED POPS TO LKLY DURING EACH
DAY. POTENTIAL CONTS TO EXIST FOR STRONG TO SVR STORMS TOMORROW AND
THURSDAY.

FROPA OCCURS BY MIDNIGHT THUR NGT. LKLY POPS ARE EXPECTED JUST ALONG
AND AHD OF THE FRONT THEN TAPER OFF TO CHC AFT 06Z FRIDAY.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
-- Changed Discussion --
AT THE START OF THE EXTENDED...DEEP UPPER-LEVEL TROUGHING WILL BE
WORKING OFF THE EAST COAST WITH STRONG HIGH PRESSURE BUILDING
SOUTHWARD ACROSS GREAT LAKES FROM CENTRAL CANADA. AS THIS
OCCURS...STRONG BLOCKING SOUTH OF GREENLAND WILL RESULT IN ONLY
A SLOW EASTWARD MIGRATION OF THE EXITING UPPER TROUGH ACROSS NEW
ENGLAND AND THE CANADIAN MARITIME PROVINCES. THIS WILL ENSURE
ARRIVING HIGH PRESSURE WILL DOMINATE THROUGH THE PERIOD WITH
LITTLE TO NO PRECIPITATION EXPECTED. WITH A DRY AIRMASS FIRMLY IN
PLACE...EXPECT A FAIRLY WIDE DIURNAL RANGE IN TEMPS WITH
OVERNIGHT LOWS EASILY FALLING INTO THE UPPER 30S AND LOWER
40S AND HIGHS ONLY REACHING INTO THE LOWER TO MIDDLE 60S. FROM
THIS VANTAGE POINT...IT SEEMS REASONABLE THAT CONDITIONS WILL
BECOME FAVORABLE FOR FROST FORMATION THROUGH THE WEEKEND AND
HEADLINES WILL LIKELY BE NEEDED AT SOME POINT.
-- End Changed Discussion --

&&

.AVIATION /16Z TUESDAY THROUGH SATURDAY/...
12Z UPDATE...
A LOWER CONFIDENCE FORECAST DURING THE TAF PERIOD IN REGARDS TO
EXACT TIMING AND PLACEMENT OF THUNDERSTORMS...BUT OUTSIDE OF ANY
THUNDERSTORMS MAINLY VFR OVERALL. OUTSIDE THUNDERSTORMS LIGHT AND
VARIABLE WIND BECOMING WEST-SOUTHWEST AT 5-10 KNOTS...THEN BACK TO
VARIABLE TONIGHT. WEAK WAVE WILL CARRY THROUGH THE AREA THIS
AFTERNOON...ALONG LIFTING SURFACE BOUNDARY...AND HEATING OF
UNSTABLE ATMOSPHERE SPROUTING SOME THUNDERSTORMS. TEMPO GROUPS
ASSIGNED TO THE BEST POTENTIAL TIMES FOR EACH TAF SITE
ACCORDINGLY /EXCEPT KAVP/. ADDITIONAL STORMS WILL BE POSSIBLE WITH A
STRONGER WAVE THIS EVENING...AS CURRENTLY DEPICTED VIA PROB30
GROUPS.

OUTLOOK...

THU/THU NIGHT...MVFR POSSIBLE IN SHOWERS/THUNDERSTORMS.

FRI/SAT...VFR.

&&

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

&&

$$
SYNOPSIS...PVN/RRM
NEAR TERM...PVN/RRM
SHORT TERM...PVN
LONG TERM...RRM
AVIATION...CMG