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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KBGM 180538
AFDBGM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BINGHAMTON NY
138 AM EDT SAT MAY 18 2013

.SYNOPSIS...
HIGH PRESSURE WILL RESIDE OVER THE REGION THROUGH SATURDAY
PROVIDING DRY WEATHER AND SEASONAL TEMPERATURES. AS THIS HIGH
PRESSURE SYSTEM MOVES OFF THE EAST COAST, A SOUTHERLY FLOW OF
SOMEWHAT MOIST AIR WILL BRING ISOLATED TO SCATTERED SHOWERS,
SUNDAY THROUGH MONDAY.

&&

.NEAR TERM /THROUGH TODAY/...
IR IMAGERY CONTS TO SHOWS PATCHY CI ADVECTING EASTWARD ACROSS NY
AND PA DURING THE LATE EVENING HOURS. SOME OF THIS HIGH LEVEL
MOISTURE WAS ASSOCIATED WITH CONVECTION UPSTREAM OVER THE UPPER
MID-WEST. THESE CLDS WILL CONT EASTWARD OVERNIGHT AS THE REGION
FALLS UNDER CONFLUENT UPPER LEVEL FLOW WHICH IS FORCING A SFC HIGH
OVER NY/PA. WINDS WERE LIGHTENING AND THERE WILL BE SOME DECENT NET
RADIATIONAL COOLING OVERNIGHT. THE CI WILL TEND TO HOLD UP SOME OF THE
MIN/S SINCE THE AIR MASS IN PLACE IS STILL RATHER DRY AND CHILLY.
SEE NO FROST ISSUES. TEMPS, SKY COVER AND WINDS LOOK ON TRACK AND
JUST DID SOME MINOR TWEAKS.

FOR SATURDAY...SFC HIGH PRESSURE AND ASSOCIATED UPPER LVL
CONFLUENT ZONE PUSHES FARTHER E AND A LIGHT SOUTHERLY LOW-LEVEL
RETURN FLOW SETS UP. THIS WILL BEGIN THE SLOW PROCESS OF
INCREASING LOW-LEVEL MOISTURE. MOISTURE WILL MOVE INTO QUICKER
ACROSS THE FINGER LAKES/NE PA VS FARTHER NE. BUT NEVERTHELESS ALL
AREAS WILL SEE LL MOISTURE INCREASE SATURDAY. IN ADDTN THERE WILL
BE PLENTY OF INSOLATION TO WARM THE SFC LAYER. I EXPECT THE BNDRY
LAYER TO GROW TO CLOSE TO 800 MB WITH NEARLY FULL SUN. WITH ADDED
MOISTURE MORE CU WILL FORM ACRS FORECAST AREA SAT. IN
ADDTN...THERE WAS A SMALL SHRT WAVE THAT WAS SEEN IN THE WATER
VAPOR IMAGERY OVER SC CANADA N OF MINN WHICH WILL RIPPLE
SOUTHEASTWARD SAT. THIS WILL LEAD TO SOME COOLING AT MID- LEVELS
IN CONCERT WITH THE DAY/S HEATING AND INCREASING LL MOISTURE.
MODEL SOUNDINGS FOR NAM12...4KM NAM...GFS...SREF AND LOCAL WRF ALL
INDICATE SOME INSTABILITY DEVELOPS BELOW 10 KFT BUT THERE WAS ENUF
OF A CAPPING INVERSION TO KEEP CHANCES FOR THUNDER SAT PM NEAR
ZERO. FORCING WAS ALSO WEAK SO I SEE JUST AN ISLD SHRA OR TWO W/ THIS
PATTERN MAINLY ACROSS OUR SW 1/2 OF OUR FORECAST AREA WHERE THERE
WILL BE MORE LL MOISTURE RETURN FLOW INCREASING THE CHANCES FOR
SOME SMALL INSTABILITY UNDER THE INVERSION. LL/S WERE STILL
DRY...ESP TO THE NE. SO CONTINUED IDEA OF DAY SHIFT OF JUST ISLD
SHRA WITH INSOLATION SAT PM MAINLY SW 1/2 OF CWA.

&&

.SHORT TERM /TONIGHT THROUGH MONDAY/...
SATURDAY...UPPER LEVEL HEIGHTS START TO RISE WHILE SFC HIGH PRES
MOVES OFF THE NEW ENGLAND COAST. PARTLY TO MOSTLY SUNNY SKIES ARE
EXPECTED ALONG WITH DRY CONDITIONS. MAX TEMPS WILL RANGE FROM THE
UPPER 60S TO MID 70S.

SATURDAY NIGHT THROUGH MONDAY...AN UPPER LEVEL RIDGE WILL BUILD
OVER THE NORTHEAST DURING THE PERIOD WITH THE RIDGE AXIS OVER THE
FA BY MONDAY MORNING. SFC HIGH PRES WILL REMAIN OFF THE NEW
ENGLAND COAST PROVIDING A RETURN FLOW OF INCREASING MOISTURE. A
WEAK WAVE OVER THE MID ATLANTIC WILL ALSO PROVIDE A BETTER
MOISTURE SOURCE FOR THE FAR SE FA. DURING THIS PERIOD WEAK MID
LEVEL WAA FORCING WILL ALSO BRING THE THREAT FOR CONVECTION.
OVERALL, ALL LIFTING AND MOISTURE ADVECTIONS ARE WEAK AND
CONSIDERING THIS IS OCCURRING UNDER A BUILDING UPPER LEVEL RIDGE
WILL CONTINUE TO ADVERTISE JUST SLIGHT CHC/CHC POPS THROUGH THE
PERIOD. ON MONDAY MODEL SOUNDINGS INDICATE CAPE VALUES OF SEVERAL
HUNDRED J/KG THEREFORE INCLUDED THUNDER.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
200 PM UPDATE...

SHAPING UP TO BE A WARM BUT UNSETTLED LONG TERM PERIOD FOLLOWED BY
A GRADUAL COOL DOWN BY THE END OF NEXT WEEK. MOST OF THE LONG
RANGE GUIDANCE IS IN GOOD OVERALL AGREEMENT THAT UPPER LEVEL
HEIGHTS WILL FALL IN THE EAST...IN RESPONSE TO A DEEPENING UPPER
LEVEL LOW OVER THE MIDWEST. AT THE SURFACE THE RESULT WILL BE AN
EAST/WEST SURFACE BOUNDARY THAT WILL START OFF TO OUR NORTH BUT
GRADUALLY SAG SOUTH DURING THE PERIOD. BOTH THE GFS AND EURO SHOW
THIS BOUNDARY MEANDERING NEAR OR OVER OUR AREA THROUGH AT LEAST
MID- WEEK. WITH THAT IN MIND WILL CONTINUE HIGH CHANCE POPS
(40-50%) AS PERIODS OF RAIN APPEAR LIKE A GOOD BET EVEN AT THIS
DISTANT VIEW. INCLUDED A MENTION OF THUNDER BOTH DAY AND NIGHT
WITH CAPES OF 500 J/KG THROUGH THE PERIOD. WE MAY COOL OFF A BIT
TOWARD THURSDAY...ESPECIALLY IF THE EURO IS CORRECT...AS THE
BOUNDARY MENTIONED ABOVE MAY SLIDE FAR ENOUGH SOUTH TO ALLOW
COOLER AIR TO FILTER IN. A MORE PRONOUNCED SHOT OF COOLER AIR
LOOKS TO BE ON TAP EARLY NEXT WEEKEND AS BOTH THE GFS AND EURO
SHOW A COLD FRONT MOVING THROUGH THE AREA...SWEEPING OUT EAST/EAST
BOUNDARY OUT TO SEA.

&&

.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
-- Changed Discussion --
OVERALL...VFR WILL PREVAIL THRU 06Z SUN. THERE WILL BE THE POTNL
FOR SOME BR THIS MRNG AT RME. AT ELM...THICKER AS/CI DECK SHUD
PRECLUDE FOG DVLMPNT. LATER THIS AFTN...PROFILES SUGGEST THE
DVLPMNT OF A 4-5KFT CU DECK ACRS THE SRN TIER OF NY AND NE PA.
AFTER 04Z...POTNL FOR A MARINE LAYER TO WORK INTO THE SRN TIER
AND NE PA ON SE/SRLY LOW LVL FLOW...AND ADDED A TEMPO GROUP AT
ELM/BGM/AVP AFTER 03-04Z. WINDS L&V OR LGT SE TIL MID MRNG...THEN
SE TO SRLY FLOW ARND 10 KTS LATE MRNG PERSISTING INTO THE EVNG
HRS.

OUTLOOK...

SUNDAY THROUGH MONDAY...POTNL FOR MVFR SUNDAY NGT INTO MON MRNG
MAINLY SRN TIER AND NE PA.

TUESDAY/WEDNESDAY...MVFR POSSIBLE IN SHOWERS/THUNDERSTORMS.
-- End Changed Discussion --

&&

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

&&

$$
SYNOPSIS...DJN
NEAR TERM...DJN
SHORT TERM...RRM
LONG TERM...HEDEN