-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KBGM 272340
AFDBGM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BINGHAMTON NY
740 PM EDT SUN JUL 27 2014

.SYNOPSIS...
A STORM SYSTEM WILL SLIDE ACROSS WESTERN NY TONIGHT, BRINGING
AN AREA OF THUNDERSTORMS INTO NY AND PA. SOME OF THE THUNDERSTORMS
WILL PRODUCE HEAVY RAINFALL AND GUSTY WINDS. MUCH COOLER WEATHER
WILL FOLLOW FOR THE START OF THE NEW WORK WEEK.

&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
-- Changed Discussion --
630 PM EDT UPDATE...
     SEVERE THUNDERSTORM WATCH 449 HAS BEEN ISSUED FOR PORTIONS OF
NORTHEAST PENNSYLVANIA THROUGH 2 AM EDT MONDAY...

AS THE UPPER LVL WAVE APPROACHES THE AREA THE SHEAR OVR THE REGION
INCREASES. AS THE SHEAR IMPROVES OVER THE REGION THE CHANCE FOR
STORMS TO BECOME SEVERE INCREASES AS WELL. WE MISSED THE WINDOW
FOR SEVERE EARLY THIS EVENING BUT THE CHANCE FOR SEVERE
THUNDERSTORMS WILL INCREASE THROUGH THE LATE EVENING HOURS. MUCAPE
IS THE HIGHEST OVER THE FAR SE PORTIONS OF THE CWA... AND EVEN
THOUGH IT IS NOT AS HIGH AS IT WAS THIS AFTERNOON... WILL SUSTAIN
THUNDERSTORM DEVELOPMENT. LOW LVL LAPSE RATES ARE FAIRLY STEEP OVER THIS
REGION AS WELL. DUE TO ENVIRONMENTAL CONDITIONS MENTIONED ABOVE...
THUNDERSTORMS MAY BECOME SEVERE OVER NORTHEAST PENNSYLVANIA
THROUGH THE EARLY MORNING HOURS ON MONDAY. THE MAIN THREAT WILL BE
STRONG WINDS AS THE SHEAR INCREASES AND HEAVY RAINFALL.

PREVIOUS FORECAST...
530 PM EDT UPDATE...
ITS STILL FAIRLY QUIET ACROSS THE CWA THIS EVENING. WE ARE
STARTING TO SEE THE SKY COVERAGE INCREASE OVER THE WESTERN
PORTIONS OF THE CWA AS THE SHORTWAVE APPROACHES AND THE MOISTURE
ATTENDANT WITH THAT SYSTEM STARTS TO PUSH IN. MUCAPE SEEMS TO BE
AROUND 1000 J/KG AND WITH THE SUN STARTING TO SET EXPECT US TO SEE
A SLOW DECREASE IN MUCAPE THROUGH THE LATE EVENING HOURS. THERE
ARE A COUPLE FACTORS THAT LOOK TO OPPOSE THE THREAT FOR SEVERE STORMS
EARLY THIS EVENING. ONE IS WE STILL LACK STRONG UPPR LVL FORCING AND
0-6KM BULK SHEAR ALSO LOOKS TO LOOK WEAK ACROSS THE AREA. WE DO
HAVE STEEP LOW AND MID LVL LAPSE RATES... SO IF SOMETHING DOES
DEVELOP AHEAD OF THE APPROACHING WAVE... STORMS MAY BE MORE ON THE
STRONG SIDE THAN SEVERE. WE ARE STILL MONITORING THE SITUATION
CLOSELY.

STILL EXPECT THE MAIN SHOW TO BE LATER THAN EARLIER. WITH SHOWERS
AND THUNDERSTORMS INCREASING FROM SOUTH TO NORTH AND CONTINUING
THROUGH THE NIGHT. LOOKS LIKE THE PRIMARY THREAT OVERALL TONIGHT WILL
BE HEAVY RAINFALL... AND THE SECONDARY THREATS MAY BE HAIL AND
STRONG WINDS.

FOR MORE INFORMATION PLEASE READ PREVIOUS FORECAST...

PREVIOUS FORECAST...
1045 AM UPDATE...
SHORT WAVE INDUCED CONVECTION HAS MOVED WELL EASTWARD, LEAVING
ISOLATED TO SCATTERED CELLS OVER THE NORTHERN FA. THE ATMOSPHERE
IS IN RECOVERY MODE AT THIS MOMENT, BUT THERE EXIST INTERESTING
SOUNDINGS UPSTREAM SOUNDINGS (12Z AT BUF, PIT, DTX) WHICH SUGGEST
FUTURE UPSTREAM DEVELOPMENT.

NOTABLE ON THE SOUNDINGS ARE AMPLE DRY AIR INTRUSIONS ALOFT AND
OBVIOUS ELEVATED MIXED LAYERS. SHEAR/HELICITY VALUES ARE MODEST,
BUT APPEAR SUFFICIENT CONSIDERING STRONG MID LEVEL LAPSE RATES.

SPC MESOSCALE PAGE SHOWS AMPLE MID LEVEL LAPSE RATES (>7C)
UPSTREAM, WHILE SPC VALUES ARE ALREADY IN THE 2-4 RANGE FROM THE
CENTRAL SOUTHERN TIER DOWN TOWARD PIT.

WE LACK AN OBVIOUS TRIGGER FOR THE NEXT SEVERAL HOURS, BUT IF WE
CAN GENERATE CONVECTION AHEAD OF THE NEXT WAVE WITHIN A FEW HOURS
OF PEAK HEATING, STRONG CONVECTION WILL BECOME LIKELY LATE IN THE
DAY. WILL NEED TO WATCH CLOSELY.
-- End Changed Discussion --

&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/...
WATER VAPOR IMAGERY SHOWS AN UNSEASONABLY VIGOROUS UPPER LEVEL
LOW RAPIDLY MOVING SOUTHEASTWARD INTO NORTHERN MINN AT THIS TIME.
THIS FEATURE WILL CONTINUE TO DROP SOUTHEASTWARD TODAY AND REACH
OHIO BY 03Z MONDAY AND OPEN UP INTO A TROUGH. THIS FEATURE WILL
PROVIDE THE UPPER LEVEL SUPPORT TO FIRE CONVECTION. THE WAVE WILL
WORK ON SIGNIFICANT INSTABILITY OVER THE LWR OHIO VALLEY TO CNTRL
APPLCNS THIS AFTERNOON AND HENCE SPC/S MODERATE RISK FOR SEVERE
WEATHER DOWN THERE. AS THIS UPPER LEVEL WAVE BEGINS TO TRACK E
INTO PA BTWN 3 AND 6Z...THE INSTABILITY WILL BE WEAKER BUT STILL,
GIVEN THE UPPER LEVEL SUPPORT, AND MIXED LAYER CAPES STILL BETWEEN
1000 AND 2000 J/KG IN NE PA AND SC NY...I THINK THERE WILL BE A
BAND OF STRONG TO SEVERE THUNDERSTORMS WORKING NORTHEAST FROM C PA
INTO NE PA AND EVENTUALLY SC NY BEFORE IT WEAKENS AND STRATIFORM
OUT IN C NY BY 6Z. STILL CONCUR WITH SPC SLGHT RISK...ESPECIALLY
FROM SC NY TO NE PA IN THE WFO BGM FORECAST AREA. FARTHER N...BY
THE TIME THE INFLUENCE OF THIS WAVE REACHES NC NY...INSTABILITY
WILL BE LESS AND THE SHEAR WON/T BE AS STRONG. BUT IN ANY EVENT
WILL CONT TO MENTION CHC FOR SVR THUNDERSTORMS IN HWO MAINLY SUN
EVENING AND NOT TAKE NC NY OUT JUST YET.

THEN BETWEEN 6Z-12Z MON THINGS GET INTERESTING. DUE TO THE DIGGING
UPPER LEVEL TROF AND CONVECTION...ALL SYNOPTIC MODELS INDICATE
THAT A LOW-LEVEL CYCLONE WILL DEVELOP FROM NW PA TO NJ. BY 12Z THE
4 MAIN SYNOPTIC MODELS...EURO...CMC...NAM AND GFS ALL DIFFER IN
THE TIMING OF THE SFC LO. THE EURO IS SLOWEST IN BRINGING IT TO SE
NY BY 18Z MON...WITH THE GFS THE FASTEST HAVING THE SFC LO OVER
NH AT THIS TIME. THE OTHER TWO MODELS ARE IN BETWEEN.

IN ANY EVENT...THE DEVELOPMENT OF THIS LOW-LEVEL CYCLONE WILL PUT
A DEFORMATION ZONE WITH SIGNIFICANT FGEN FORCING ON THE NW SIDE OF
IT...WHICH AS PER NAM...GFS...AND CMC HAS A SWATH OF HEAVY RAIN
FOR PORTIONS OF C NY AND NRN PA BTWN 6Z AND 18Z MONDAY. THE EURO
IS FARTHER W WITH THIS AXIS OF HEAVIER PRECIP. THE INTERESTING
ASPECT OF THIS THAT THERE IS A SLOPED LAYER OF FGEN FORCING ON THE
NW SIDE OF THE LOW WITH CONVECTIVE INSTABILITY ALOFT. THIS COULD
MEAN THAT AS THE BAND OF POTENTIALLY STRONG TO SEVERE STORMS THAT WORKS
NORTHEAST ACR NE PA AND SC NY...SLOWS DOWN AND EVENTUALLY BECOMES
A HEAVY RAIN PRODUCER AS IT STRATIFORM OUT. THE NAM HAS THE
HIGHEST QPF WITH 2.5 TO 3.5 INCHES ACRS C NY. THE OTHER MODELS ARE
TAMER BUT STILL HAVE UP TO 2 INCHES OR MORE. THIS COULD MEAN LOCALLY
THAT RAINFALL WHICH COULD EXCEED THREE OR EVEN FOUR INCHES LOCALLY SO
WILL HAVE TO WATCH OUT FOR THE POTENTIAL FOR FLASH FLOODING SUN
NGT AS WELL. WILL MENTION IN HWO.

FOR MONDAY DURING THE DAY...THE SFC LO PULLS OUT TO THE NE AND THE
RAINFALL STARTS TO WIND DOWN FROM SW-NE LATE IN THE DAY. THE EURO IS
SLOWEST BRINGING THE PRECIP OUT WITH THE NAM AND GFS THE FASTEST.
WILL MAINTAIN LINGERING SHRA MOST OF THE DAY AS PER SURROUNDING
OFFICES GRIDS. WOULDN`T BE SURPRISED IF PRECIP ENDS A BIT QUICKER
THAN CURRENTLY ADVERTISED MON PM THOUGH.

FOR MON NGT...ONLY THE EURO HAS LINGERING PRECIP FOR THE CATSKILLS
TO THE UPPER MOHAWK VALLEY. REST OF MODELS ARE BASICALLY DRY. FOR
NOW WILL GO WITH EURO/S AND SURROUNDING OFFICES IDEA OF SLGHT CHC
TO CHC SHRA MON EVE...THEN END PRECIP AFTER MIDNIGHT INTO ERLY
TUESDAY.

FOR TUE... HAVE POP UP SHRA GIVEN THE COLDER AIR ALOFT. TUE NGT
WILL SEE HIGH PRESSURE AND FAIR WEATHER. A FEW LINGERING SHRA
STILL POSSIBLE IN THE FINGER LAKES REGION CLOSER TO THE NEXT WAVE.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
230 PM SUN UPDATE... ON THE LARGE-SCALE...THIS PD WILL CONTINUE TO
BE CHARACTERIZED BY L/WV RIDGING OVER WRN NORTH AMER AND TROUGHING
OVER ERN SXNS. THE ERN TROUGH FEATURE WILL BE FAIRLY AMPLIFIED IN
NATURE AT THE START OF THE PD (WED NGT/THU)...ANCHORED BY A CLOSED
UPR LOW OVER THE SRN END OF HUDSON`S BAY. HOWEVER...WITH
TIME...THIS UPR LOW WILL OPEN UP AND EJECT NEWD...WITH THE TROUGH
AXIS GRADUALLY FILLING.

AS FOR OUR DAILY SENSIBLE WX...RESIDUAL COLD POOLING ALOFT ASSOCD
WITH THE ABV DESCRIBED TROUGH SHOULD TRANSLATE INTO SCTD DIURNAL
SHWRS/TSTMS MOST OF THIS PD...WITH THE COVERAGE OF SAID ACTIVITY
SLOWLY DIMINISHING TWDS NEXT WEEKEND. TEMPS SHOULD AVERAGE NEAR OR
SLIGHTLY BLO CLIMO...WITH HIGHS RANGING FROM THE MID 70S-LWR
80S...AND LOWS MOSTLY IN THE 50S-LWR 60S.

&&

.AVIATION /00Z MONDAY THROUGH FRIDAY/...

-- Changed Discussion --
STRONG WV AND COLD FNT APRCHG THIS EVE AND WILL SPREACONV SHWRS
AND TERWS INTO THE AREA. INCRSD MOSITURE WITH THE PCPN WILL LWR
CIGS AND VSBYS AT TIMES INTO THE IFR RANGE OVRNGT. ACTIVITY WILL
SLOWLY WEAKEN TWRD MRNG...BUT CIGS AND VSBYS WILL BE SLOW TO RCVR.
ON MON...BLUSTERY CONDS WITH CAA WILL CREATE MVFR OVC CONDS FOR
MUCH OF THE DAY WITH OCNL LGT SHWRS.

OUTLOOK...

TUE-FRI...RESTRICTIONS POSSIBLE EACH AFTERNOON...WITH SCTD
SHWRS/TSTMS ANTICIPATED.
-- End Changed Discussion --

&&

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

&&

$$
SYNOPSIS...DJP
NEAR TERM...DJP/KAH
SHORT TERM...DJP
LONG TERM...MLJ
AVIATION...DGM/MLJ