FXUS61 KCTP 261232
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
732 AM EST SAT DEC 26 2009

.SYNOPSIS...
LOW PRESSURE WILL TRACK NORTHWARD ACROSS EASTERN PENNSYLVANIA
TODAY. AN UPPER LEVEL LOW PRESSURE SYSTEM OVER THE MIDWEST WILL
TRACK EAST ACROSS PENNSYLVANIA BY MONDAY. HIGH PRESSURE WILL BUILD
OVER THE REGION AT MIDWEEK. HOWEVER...AN EAST COAST STORM COULD
POTENTIALLY THREATEN PENNSYLVANIA BY LATE NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SATELLITE IMAGERY SHOWING UPPER LOW PARKED OVER THE MIDWEST THIS
MORNING...WHILE PLUME OF ANOMALOUS PWATS EXTENDS ALONG AXIS OF LL
JET FROM CAPE HATTERAS NWRD INTO CENTRAL PA. SFC LOW...CURRENTLY
OVR SE VIRGINIA...IS PROGGED TO TRACK ACROSS EASTERN PA LATER
TDY...KEEPING THE RAIN/DZ GOING ALL DAY FROM THE SUSQ VALLEY
EASTWARD. ACROSS WESTERN PA...ARRIVAL OF OCCLUDED FRONT WILL BRING
AN END TO THE RAIN LATER TDY. STRONG LL JET WORKING ACROSS EASTERN
PA WILL CONTINUE TO CREATE GUSTY WINDS NR THE SFC...ESP
DOWNWIND /WEST/ OF THE RIDGETOPS. LATEST BUFKIT DATA SUPPORTS
GUSTS ARND 25KTS CONTINUING FOR MUCH OF THE DAY ACROSS EASTERN PA. 

RIVER LVLS HAVE NOT RESPONDED MUCH TO THE RAIN SO FAR.
HOWEVER...LATEST MARFC GUIDANCE INDICATES WE WILL BEGIN TO SEE
MODEST RISES...ESP SE PA...AS HIGHER DWPTS WORK INTO THE AREA.
LATEST GEFS MEAN QPF RANGING CLOSE TO 0.5 INCHES TDY OVR MUCH OF
CENTRAL PA. HOWEVER...LOCALIZED AMTS IN EXCESS OF 1 INCH OVR THE
HIGH TERRAIN OF EASTERN PA SEEM REASONABLE...GIVEN THE ANOMALOUS
MOISTURE PLUME AND POTENTIAL FOR TOPOGRAPHIC ENHANCEMENT. THAT
SAID...6HR FFG BTWN 2 AND 3 INCHES SUGGEST SIG FLOOD THREAT
REMAINS LOW.

MODEL SOUNDINGS SUGGEST JUST ENOUGH COLD AIR ON THE BACK EDGE OF
PRECIP SHIELD TO SUPPORT A BRIEF CHANGEOVER TO SNOW OVR THE N MTNS
LATER TDY. ANY ACCUMS SHOULD BE NEGLIGIBLE.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/...
DRY SLOT SHOULD WORK INTO THE AREA TONIGHT...BRINGING PARTIAL
CLEARING. STEEPENING LPS RTS AHEAD OF APPROACHING UPPER LO WILL
BRING AN INCREASING CHC OF SHSN ON SUNDAY. ENS MEAN QPF INDICATES LGT
ACCUMS OF LESS THAN AN INCH POSSIBLE BY SUN AFTN OVR THE NW MTNS
AND LAUREL HIGHLANDS. MODEL 900MB TEMPS SUGGEST HIGH TEMPS SUNDAY RANGING
FROM THE L30S NW MTNS TO M40S LOWER SUSQ VALLEY.

&&

.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
UPPER LOW WILL LIFT NORTHEAST ACROSS THE E GRT LKS SUNDAY NIGHT.
LG SCALE FORCING AHEAD OF THIS FEATURE WILL LIKELY SUPPORT A
PERIOD OF SNOW OVR THE ALLEGHENY MTNS SUNDAY NIGHT...WITH SHSN
POTENTIALLY EVEN SURVIVING DOWNWIND OF THE MTNS INTO THE SUSQ
VALLEY. 

BRISK/WINDY CONDS AND LES SHWRS WILL ACCOMPANY A REINFORCING SURGE
OF COLDER AIR MON NGT/TUE. HIGH PRES SHOULD BRING SOME IMPROVEMENT
BY THE MIDDLE OF NEXT WEEK. THIS 36-48 HOUR PERIOD WILL LIKELY
CONTAIN SEVERAL INCHES OF SNOW ACROSS THE SNOW BELT OF NW PA.

THE MOST TRANQUIL /THOUGH STILL COLD/ PERIOD NEXT WEEK WILL BE
TUESDAY NIGHT THROUGH WEDNESDAY NIGHT AS A LARGE AREA OF HIGH
PRESSURE BUILDS ENE FROM THE OHIO VALLEY.

STRONG NEG AO/NAO...+ PNA AND A SRN STREAM EL NINO CONNECTION
WL CONT TO OFFER A SET UP FAVORABLE FOR EAST COAST WINTER STORMS.
12Z GEFS...AND THE OPERATIONAL 06Z EC/ 12Z GFS STILL SHOW A
DEVELOPING AREA OF LOW PRESSURE MOVING NNE - SEVERAL HUNDRED KM
OFF THE SE AND MID ATLANTIC COAST TOWARD THE START OF THE NEXT
DECADE...STAY TUNED. FOR NOW...WILL BROAD-BRUSH A 30-40 PERCENT
CHC FOR SNOW NEW YEARS EVE INTO THE FIRST DAY OF 2010. 12Z
ECMWF...HAS SHOWN A TYPICAL WWD JOG TO THE PATH OF THE LOW - NOW
CLOSER TO THE MID ATLANTIC COAST...WITH A BETTER CHC FOR SNOW
ACROSS OUR CENTRAL AND ERN ZONES LATE NEW YEARS DAY INTO JAN 2ND.

&&

.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
SFC LOW OVR SE VIRGINIA AT 12Z...IS PROGGED TO TRACK ACROSS EASTERN
PA LATER TDY KEEPING THE RAIN/DZ GOING /ALONG WITH PRIMARILY MVFR
CONDITIONS/ FOR THE MAJORITY OF THE DAY IN SUSQ VALLEY. ACROSS
WESTERN PA...ARRIVAL OF OCCLUDED FRONT WILL BRING AN END TO THE
RAIN EARLY THIS AFTERNOON /WITH A BRIEF CHANGOVER TO SNOW POSSIBLE
IN THE NW MTNS BEFORE ENDING/ AS CONDITIONS IMPROVE BACK TO VFR
AROUND 21Z. STRONG LL JET WORKING ACROSS EASTERN PA WILL CONTINUE
TO CREATE GUSTY WINDS NR THE SFC...ESP DOWNWIND /WEST/ OF THE
RIDGETOPS.

OUTLOOK... 
SUN-TUE...NW FLOW. MVFR/IFR WEST WITH FREQ SNOW SHOWERS. CNTRL/EAST
VFR/MVFR WITH SCATTERED SNOW SHOWERS.
WED...VFR.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$
SYNOPSIS...FITZGERALD
NEAR TERM...FITZGERALD
SHORT TERM...FITZGERALD
LONG TERM...FITZGERALD/LAMBERT
AVIATION...RXR