-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KBGM 212246
AFDBGM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BINGHAMTON NY
646 PM EDT TUE MAY 21 2013

.SYNOPSIS...
A WARM AND HUMID AIRMASS WILL REMAIN OVER THE REGION THROUGH
WEDNESDAY NIGHT. SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE
THROUGH THIS PERIOD ALONG WITH WARM TEMPERATURES. A COLD FRONT
WILL APPROACH THE REGION LATE WEDNESDAY NIGHT AND CROSS THE AREA
ON THURSDAY. THIS SYSTEM WILL BRING A BETTER CHANCE FOR SHOWERS
AND THUNDERSTORMS THROUGH THURSDAY EVENING.

&&

.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
-- Changed Discussion --
640 PM UPDATE...
PLENTY OF INSTABILITY...BUT LIMITED TRIGGERS. HOWEVER...SHALLOW
WARM FRONT HAS SERVED PURPOSE OF BEING AN EFFECTIVE TRIGGER...AND
THUS ACTIVITY HAS BEEN MOST ENHANCED ALONG AND NORTH OF LIFTING
FRONT IN CENTRAL NEW YORK. CURRENT SEVERE CELLS AND ONE WITH
STRONG ROTATION /HAS TORNADO WARNING/ WILL CONTINUE EASTWARD
PROGRESSION THROUGH ABOUT 9 PM. AFTER THAT...SHORTWAVE CURRENTLY
IN EASTERN OHIO WITH LIMITED CONVECTION...MAY TRY TO HARNESS
SIGNIFICANT AMOUNT OF INSTABILITY THAT STILL EXISTS WITHIN WARM
SECTOR LATER THIS EVENING. COVERAGE AND UNCERTAINTY FOR THAT LATER
ACTIVITY HOWEVER...SO ONLY CHANCE POPS ASSOCIATED WITH IT AT THIS
TIME.

PREVIOUS DISCUSSION...
AT 4 PM...A WARM AND HUMID AIRMASS IS OVER THE REGION WITH 100 MB
MIXED LAYER CAPES RANGING FROM 1500-2000. A WEAK WARM FRONT
REMAINS OVER NRN NYS AND A MID LEVEL SHORT WAVE WILL CROSS THE
REGION THIS EVENING AS THE UPPER LEVEL RIDGE BEGINS TO FLATTEN.
EVEN THOUGH FORCING MECHANISMS REMAIN FAIRLY WEAK THESE FEATURES
ALONG WITH THE AVAILABLE CAPE WILL KEEP THE THREAT FOR SCATTERED
CONVECTION THROUGH LATE EVENING ALONG WITH THE CHANCE FOR SOME TO
BECOME SEVERE WITH DAMAGING WINDS AND LARGE HAIL THE PRIMARILY
THREAT.

LATE TONIGHT, ACTIVITY WILL CONTINUE TO DIMINISH IN AREAL COVERAGE
AS THE WARM FRONT CONTINUES TO LIFT NORTH AND THE MID LEVEL SHORT
WAVE MOVES EAST OF FA. OVERNIGHT LOWS WILL RANGE IN THE LOWER TO
MIDDLE 60S.
-- End Changed Discussion --

&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
WEDNESDAY...UPPER LEVEL RIDGE CONTINUES TO FLATTEN AS UPPER LEVEL
TROF IN THE MID WEST MOVES SLOWLY EAST. AREA WILL RESIDE WELL INTO
THE WARM SECTOR WITH MID LEVEL SHORT WAVES MOVING THROUGH IN SOUTHWEST
FLOW. MAX TEMPS WILL RUN ABOUT THE SAME AS TODAY MAYBE A COUPLE OF
DEGREES COOLER AS T85 DROPS OFF A FEW CELSIUS. MODEL SOUNDINGS
INDICATE LESS CAPE THAN TODAY WILL VALUES RANGING FROM 1000/1500
J/KG. WIND FIELDS REMAIN FAIRLY MARGINAL FOR SEVERE WEATHER BUT
JET DYNAMICS ARE BETTER THAN TODAY AS REGION WILL RESIDE IN THE
RIGHT ENTRANCE REGION. WILL INCREASE POPS THROUGHOUT THE DAY BUT
MAX THEM OUT AT HIGH CHC. THERE WILL CONTINUE TO BE THE POTENTIAL
FOR A FEW STORMS TO BECOME SEVERE WITH THE PRIMARY THREAT DAMAGING
WINDS AND LARGE HAIL.

WEDNESDAY NIGHT/THURSDAY...H5 TROF CURRENTLY OVER THE MID WEST
WILL REACH THE WESTERN LAKES BY AFTERNOON. SFC LOW PRES WILL WILL
TRACK FROM THE UPPER GREAT LAKES INTO NEARBY SOUTHERN ONTARIO
WEDNESDAY NIGHT. AS THE SFC LOW CONTINUES MOVING NORTHEAST INTO
QUEBEC THE TRAILING COLD FRONT WILL MOVE THROUGH DURING THE
AFTERNOON AND EVENING. WINDS FIELDS AND BULK SHEAR VALUES BECOME
MORE FAVORABLE FOR SEVERE THUNDERSTORMS BUT JET DYNAMICS ARE FAIRLY
WEAK AND ATMOSPHERE IS FORECAST TO BE NOT NEARLY AS UNSTABLE AS
TODAY AND WEDNESDAY. SHOWERS AND THUNDERSTORMS WILL BECOME MORE
WIDESPREAD AS THE UPPER LEVEL TROF AND SFC FEATURE APPROACH THE
AREA LATE WED NIGHT WITH ACTIVITY CONTINUING THROUGH THURSDAY. WILL
INCREASE POPS TO LIKELY LATE WED NIGHT WITH LIKELY POPS ON
THURSDAY.

THURSDAY NIGHT/FRIDAY...UPPER LEVEL TROF WILL MOVE INTO THE
NORTHEAST. SFC COLD FRONT WILL MOVE EAST OF FA BY EARLY EVENING
BUT DEEP UPPER LEVEL TROF WILL KEEP THE CHANCE FOR SHOWERS THROUGH
FRIDAY. STRONG CAA POST FRONTAL WILL MAKE FOR MUCH COOLER MAXES ON
FRIDAY RANGING FROM THE UPPER 50S TO LOWER 60S IN NYS TO LOW TO
MID 60S IN NE PA.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
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.

&&

.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
CONFIDENCE IN THE VERY SHORT TERM 2-4 HOUR CONVECTIVE TREND FORECASTS
IS OVERALL GOOD WITH A WELL DEFINED CONVERGENCE ZONE ACROSS NORTH
CENTRAL NY THIS AFTERNOON. A LOT OF THE TSRA ACTIVITY WILL REMAIN
ISOLD-SCT AND PROBABLY WILL NOT AFFECT MUCH TERMINAL OPERATION...BUT
THE HIGHEST CHANCE SEEMS TO BE IN THE KSYR-KRME AREA THROUGH 21Z
BASED ON THE LATEST THERMODYNAMIC AND FORCING PARAMETERS. THESE ARE
THE ONLY LOCATIONS WE HAVE INCLUDED TSRA IN FORECAST ATTM WITH
CONFIDENCE...BUT KBGM-KITH ARE CLOSE AND NEED TO BE MONITORED FOR
ACTIVITY IN VCNTY. FURTHER SOUTH AND WEST THE CHANCES AND CONFIDENCE
IS GENERALLY LOW. BEYOND THIS AFTERNOON...WE BELIEVE THAT MODEL
SOLUTIONS INDICATING SIGNIFICANT DEVELOPMENT OF SHRA/TSRA TONIGHT
LOOK OVERDONE. MESOSCALE MODELS ARE OVERDONE IN STORM COVERAGE
NOW...AND THERE DOES NOT APPEAR TO BE A SIGNIFICANT TRIGGER
MECHANISM TO GENERATE ADDITIONAL STORM ACTIVITY IN A STABILIZING
ENVIRONMENT TONIGHT. WILL FOCUS ON A MORE OPTIMISTIC SOLUTION OF
VFR...BECOMING MVFR CIGS/VSBY IN SPOTS DUE TO MOIST BOUNDARY LAYER
LATER TONIGHT. WILL HOLD OFF PUTTING STORMS IN FORECAST UNTIL
DEVELOPMENT OCCURS...OR A SUBSTANTIVE WAVE IS DETECTED. ON
WEDNESDAY...ENVIRONMENT RETURNS TO CONVECTIVELY UNSTABLE...BUT
WELL WITHIN WARM SECTOR WITH AGAIN ONLY ISOLD-SCT ACTIVITY
POSSIBLE TOWARD 18Z.

MIXED WIND FIELDS THIS AFTERNOON FROM NW-N ACROSS NORTHERN THIRD
OF REGION...TO SW 5-15 KTS SOUTHERN 2/3RDS. LIGHT WINDS
OVERNIGHT...BECOMING SW 5-10 KTS WEDNESDAY.

OUTLOOK...

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

FRI...VFR/MVFR.

SAT-SUN...VFR. BREEZY.

&&

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

&&

$$
SYNOPSIS...RRM
NEAR TERM...MDP/RRM
SHORT TERM...RRM
LONG TERM...CMG
AVIATION...JAB