-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KBGM 201832
AFDBGM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BINGHAMTON NY
232 PM EDT MON MAY 20 2013

.SYNOPSIS...
A FEW SHOWERS OR THUNDERSTORMS WILL BE POSSIBLE TODAY AS A FRONTAL
BOUNDARY REMAINS NEAR OUR AREA. A BETTER THREAT FOR SHOWERS AND
THUNDERSTORMS WILL COME TUESDAY AND BEYOND AS A MORE SIGNIFICANT
FRONT AND LOW PRESSURE SYSTEM MOVE CLOSE TO OUR AREA. THE BIGGER
STORY WILL BE WARMER WEATHER WITH HIGH TEMPERATURES IN THE 70S TO
NEAR 80 THROUGH THE MIDDLE OF THE WEEK.

&&

.NEAR TERM /THROUGH TUESDAY/...
UPDATED AT 1 PM... WEAK FRONTAL BOUNDARY IS CURRENTLY LOCATED
ACROSS FAR NORTHERN NEW YORK. SKIES HAVE BECOME PARTLY CLOUDY
SOUTH OF THE BOUNDARY ACROSS OUR AREA WITH SOME CONVECTIVE CLOUDS
DEVELOPING BUT NO INDICATIONS OF ANY DEEP CONVECTIVE DEVELOPMENT
THROUGH EARLY THIS AFTERNOON. LATEST RAP FORECASTS FOR THIS AFTERNOON
INDICATE INCREASING IN INSTABILITY WITH CAPE VALUES CLIMBING TO
800-1000 J/KG. HOWEVER SYNOPTIC-SCALE FORCING LOOKS WEAK WITH THE
FRONTAL BOUNDARY EXPECTED TO REMAIN TO THE NORTH. SOME HIGH
RESOLUTION MODELS SHOWING ISOLATED CONVECTIVE SHOWERS DEVELOPING
OVER CENTRAL NY LATER THIS AFTERNOON WITH COVERAGE LESS THAN 30
PERCENT. WEAK WIND FIELDS WOULD MEAN THAT ANY STORMS THAT DEVELOP
WILL BE OF THE PULSE VARIETY WITH ANY SEVERE THREAT LOW. WITH
CLEARING TEMPERATURES HAVE CLIMBED INTO THE 70S AND MANY PLACES
WILL REACH NEAR 80 THIS AFTERNOON.


1000 AM UPDATE...MADE MINOR CHANGES TO SHOW MORE OF A DRY FORECAST
ACROSS OUR AREA NOW AND FOR THE NEXT FEW HOURS AS THE CLOSEST AREA
OF SHOWERS OVER NNY WILL SAFELY PASS TO OUR NORTHEAST. STILL NOT
SEEING ANY BIG TRIGGERS FOR SHOWERS OR CONVECTION THIS AFTERNOON
SO SLIGHT CHANCE POPS SEEMS GREAT. THE HRRR DOES SHOW SOMETHING
CROSSING LAKE ERIE LATE IN THE DAY AND IT DOES MATCH UP NOW WITH A
DEVELOPING LINE OF CONVECTION OVER LOWER MICHIGAN SO WE WILL WATCH
THIS CLOSELY. IN ADDITION WHILE DRY NOW...VIS SATELLITE DOES SHOW
SOME MORE LUMPY OR CONVECTIVE LOOKING CUMULUS OVER THE FAR
NORTHEAST END OF LAKE ONTARIO SO THIS MAY TURN INTO SOMETHING IN
THE NEXT FEW HOURS. AGAIN NOT MUCH EXPECTED BUT ENOUGH AROUND TO
WARRANT AT LEAST A MENTION THIS PM. UNLIKE YESTERDAY SUNSHINE OVER
IS ALREADY OVER THE NORTHERN PART OF THE CWA AND WILL CONTINUE TO
PUSH SOUTH THROUGH MIDDAY. TEMPS LOOK ON TRACK TO REACH THE 70S.
THE PREVIOUS AFD IS BELOW...



4 AM UPDATE...
WK SFC LOW LOCATED ACRS SRN QUEBEC WL SLIDE OFF TO THE EAST TDA AS
UL WV PULLS EAST. AS IT DOES SO A WK SFC TROF WL APPCH NRN ZONES
THIS AFTN BFR IT WASHES OUT. AT THE SAME TIME A STRONG CLOSED LOW
ALOFT WL PINWHEEL ACRS THE NRN PLAINS FOR THE NEXT DAY OR TWO. THIS
LOW WHICH WAS RESPONSIBLE FOR YDA`S TORNADO OUTBREAK ACRS THE SRN
PLAINS IS ESSENTIALLY BLOCKED IN PLACE BY RIDGING TO THE EAST AND
WEST. LOW PROGGED TO BE STACKED THRU TUESDAY SWINGING A WMFNT THRU
THE AREA ON MON NGT.

FOR TDA, PATCHY FOG AND DRIZZLE CAN BE EXPECTED ACRS SRN ZONES AS
MARINE LYR RMNS THRU AT LEAST 12Z. AFT THIS TIME, WINDS BCM MORE
SWRLY LEADING TO SOME IMPROVEMENT IN LOW CLDS. WHILE LOW-LVL
MOISTURE WL RMN IN PLACE THIS AFTN, VRY LITTLE FRCG WL BE AVAILABLE
FOR ANY NOTICEABLE PCPN TDA AND WITH MODELS CONTG TO INDICATE
WIDESPREAD QPF ACRS THE AREA AND GIVEN THEIR PERFORMANCES THE LAST 2
DAYS, HV LWRD POPS OVR ENTIRE CWA TO ISOLD AT BEST. IS THE POTENTIAL
FOR AN ISOLD RUMBLE OR TWO OF THUNDER AND HV INCLUDED MENTION TWD
NOON UP NR BNDRY SLIPPING THRU AND OVRSPRDNG ENTIRE AREA THRU ABOUT
21Z. OF COURSE, LIMITATIONS EXIST STRICTLY FM EXTENSIVE CLD CVR
ALONG WITH WK FRCG BUT FEEL CHCS ARE NOT COMPLETELY NIL SO HV CONTD
ISOLD SHRA/TSRA CHC FOR THE AFTN.

FOR TONIGHT, WMFNT LIFTS THRU WITH OVRNGT LOWS EXPECTED TO RMN ARND
60F. DWPTS WL ONLY DROP INTO THE U50S. SKIES WL RANGE FM
PRTLY-MOCLDY DRG THE NIGHTTIME HRS WITH BNDRY IN VICINITY. SLGT CHC
POPS THRU MOST OF THE OVRNGT HRS THEN SLOWLY INCRSNG TWD DAWN FM THE
WEST AS ISENTROPIC LIFT INCREASES.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
4 AM UPDATE...
SW FLOW CONTS ON TUESDAY PER 00Z NAM AND ECMWF. MODELS PLACE CWA
SQUARELY IN THE WARM SECTOR DRG THE DAY. H5 RIDGE BEGINS TO WEAKEN
DRG THE AFTN AS PLAINS LOW BEGINS TO EJECT TO THE EAST. THIS WL
ALLOW WK S/WV TO IMPACT AREA DRG THE DAY, LEADING TO LKLY POPS AFT
18Z. AIRMASS WL LKLY DESTABILIZE IN WM SECTOR LEADING TO CAPES ARND
1000 J/KG BASED ON TEMPS IN THE LWR 80S AND DWPTS RISING INTO THE
MID-60S.

CHC FOR SHOWERS AND TSTMS CONTINUES THRU THE DAY ON WED AS WMFNT
RMNS TO OUR NORTH AND INSTABILITY GRADUALLY INCREASES. DUE TO
PROXIMITY OF BNDRY, SHOWERS APPEAR TO BE LKLY AT TIMES DRG THE DAY
ACRS CNTRL NY CNTYS WHILE ONLY SCTD THUNDER CAN BE EXPECTED, THUS HV
WORDED GRIDS AS LKLY SHOWERS AND CHANCE THUNDER.

MAV NUMBERS LOOK WAY TOO WARM FOR HIGHS ON WEDNESDAY DUE TO THE
GFS/S LACK OF CLD CVR. THINKING IS THAT MET NUMBERS WILL BE CLOSER
TO REALITY AND VLY LOCALES MAY HIT 80F BUT HILLTOPS WL RMN IN THE
U70S.

HV CONTD LKLY POPS WED NGT AS CD FNT APPCHS WRN NY AND H5 LOW EJECTS
INTO GREAT LKS, FLINGING WVS AT TIMES THRU THE PD. HV MADE VRY FEW
CHGS TO PRVS GRIDS.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
-- Changed Discussion --
MEDIUM RANGE MODELS CONTINUE TO SHOW A DEEP UPPER LEVEL TROF OVER
THE NORTHEAST THROUGH MOST OF THE PERIOD WITH HEIGHTS GRADUALLY
BUILDING LATE AS THIS TROF LIFTS EAST. THIS WILL KEEP TEMPERATURES
5-10 DEGREES BELOW NORMAL WITH MIN TEMPS COLD ENOUGH FOR POSSIBLE
FROST BOTH FRIDAY/SATURDAY NIGHTS AND MAYBE EVEN SUNDAY NIGHT.

AT THE SFC, POST COLD FRONT SHOWERS/THUNDERSTORMS WILL LINGER
THROUGH THE OVERNIGHT PERIOD WITH BEST CHC FOR THUNDER DURING THE
EARLY EVENING. AS THE UPPER LEVEL TROF BUILDS IN ON FRIDAY THE CHC
FOR SHOWERS WILL CONTINUE WITH THE HIGHEST POPS IN THE SOUTHERN
CATSKILLS AND NE PA. REMAINDER OF PERIOD WILL BE DRY WITH PARTLY
TO MAINLY CLEAR CONDITIONS AS SFC HIGH PRES FROM CENTRAL CANADA
DROPS SOUTH ACROSS THE GREAT LAKES REGION TO OUR VCNTY BY MONDAY.
-- End Changed Discussion --

&&

.AVIATION /18Z MONDAY THROUGH SATURDAY/...
-- Changed Discussion --
CONDITIONS ARE VFR ACROSS THE TERMINALS THIS AFTERNOON AND IN
GENERAL WILL REMAIN VFR THROUGH THIS TAF PERIOD. LATE TONIGHT, MVFR
CONDITIONS ARE POSSIBLE AT KELM DUE TO VALLEY FOG AND KAVP WITH
POSSIBLE MARINE LAYER.

THERE IS THE POTENTIAL FOR CONVECTION PRIMARILY TUESDAY AFTERNOON AS
WEAK BOUNDARY OVER NORTHERN NY MAY BECOME ACTIVE WITH DIURNAL
INSTABILITY. SHOWERS/THUNDERSTORMS ARE NOT INCLUDED IN THE TAFS
ATTM AS THE BEST CHANCE LOOKS AFTER 18Z BUT OVERALL A LOW
CONFIDENCE CONVECTIVE EVENT UNFOLDING TOMORROW AFTERNOON.

LIGHT AND VARIABLE WITH THROUGH TONIGHT BECOMING SOUTHWEST AT
5-10 KNOTS TUESDAY MORNING.

OUTLOOK...

WEDNESDAY/THURSDAY...MVFR POSSIBLE IN SHOWERS/THUNDERSTORMS.

FRIDAY/SATURDAY...VFR.
-- End Changed Discussion --

&&

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

&&

$$
SYNOPSIS...PVN
NEAR TERM...MSE/PVN
SHORT TERM...HEDEN/PVN
LONG TERM...RRM
AVIATION...RRM