FXUS61 KCTP 270025
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
725 PM EST SAT DEC 26 2009

.SYNOPSIS...
LOW PRESSURE WILL TRACK NORTHEASTWARD AND OFF OF THE NEW JERSEY
COAST BY EARLY SUNDAY...TAKING MOST OF THE LINGERING RAINFALL AND
DRIZZLE WITH IT. ON THE BACKSIDE OF THIS STORM...COLDER AIR WILL
OVERSPREAD WESTERN AND CENTRAL PORTIONS OF THE STATE BY MORNING...
WITH FLURRIES AND LAKE EFFECT SNOW SHOWERS ACCOMPANYING THE COLD AIR.
AN UPPER LEVEL LOW PRESSURE SYSTEM OVER THE MIDWEST WILL TRACK
EAST ACROSS PENNSYLVANIA BY MONDAY...AND ANOTHER BY EARLY TUESDAY...
SPREADING ADDITIONAL FLURRIES AND SNOW SHOWERS ACROSS THE
COMMONWEALTH ALONG WITH SHARPLY COLDER AND WINDY CONDITIONS. HIGH
PRESSURE WILL BUILD OVER THE REGION AT MIDWEEK. HOWEVER...AN EAST
COAST STORM COULD POTENTIALLY THREATEN PENNSYLVANIA TO CLOSE OUT
THIS YEAR OR RING IN THE NEXT.

&&

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
RAINFALL HAS REALLY DIMINISHED THIS AFTERNOON AS THE COASTAL LOW
TRACKS NORTHWARD. ADDITIONAL AMOUNTS OF ONLY .01 OR .02 PER HOUR
ARE BEING OBSERVED ACROSS THE LOWER SUSQ. RIVER VALLEY...BUT SNOW
MELT CONTINUES. EARLIER ISOLATED MINOR FLOODING PROBLEMS DO NOT
APPEAR TO HAVE WORSENED...BUT WE DO EXPECT SOME SIGNIFICANT RISES
ON STREAMS AND CREEKS IN THE AREA...AND SHERMAN CREEK AT
SHERMANSDALE ROSE ABOVE CAUTION STAGE AT 1 PM THIS AFTERNOON AND
WILL CREST BELOW FLOOD STAGE TONIGHT.

STRONG LL JET WORKING ACROSS EASTERN PA WILL CONTINUE TO CREATE
GUSTY WINDS NR THE SFC...ESP DOWNWIND /WEST/ OF THE RIDGETOPS.
BUFKIT DATA SUPPORTS GUSTS ARND 25KTS CONTINUING FOR MUCH OF THE
DAY ACROSS EASTERN PA.

COLDER AIR ARRIVES LATER THIS EVENING AND LATE TONIGHT ACROSS THE
NORTHWEST CHANGING LINGERING DRIZZLE AND LIGHT -SHRA TO -SHSN. NOT
EXPECTING MUCH IN THE WAY OF ACCUMS HOWEVER UNTIL FLOW BECOMES
MORE WESTERLY BY LATE SUNDAY AT THE EARLIEST.

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/...
UPPER LOW TRACKS EASTWARD ACROSS CENTRAL PA ON SUNDAY WITH COLD
AIR PUSHING INTO EASTERN PA FINALLY. INCREASING CHC OF SNOW
SHOWERS WILL ACCOMPANY THIS WITH SOME MINOR ACCUMULATIONS EXPECTED
MAINLY OVER NORTHWEST SECTIONS. ENS MEAN QPF INDICATES LGT ACCUMS OF 
LESS THAN AN INCH POSSIBLE BY SUN AFTN OVR THE NW MTNS AND LAUREL
HIGHLANDS.

&&

.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
RIDGE OVER GREENLAND WILL CONTINUE TO BUILD THROUGH THE EXTENDED
PERIOD. THIS WILL RESULT IN A LARGE SCALE TROUGH OVER THE EASTERN
US THROUGH THE NEW YEAR. SEASONABLY COLD OR SLIGHTLY BELOW NORMAL
TEMPERATURES WILL PERSIST THROUGH THE WEEK.

HUGE UPPER LOW THAT HAS BEEN AFFECTING THE UPPER MIDWEST WILL
TRICKLE TO THE EAST OVER THE NEXT 48-72 HOURS. THIS WILL HELP
USHER IN COOLER AIR AND A CHANGEOVER FROM RAIN/DRIZZLE TO SNOW
EARLY THIS WEEK. SREF ENSEMBLE AND HIGH RESOLUTION MODELS INDICATE
LIGHT MEASURABLE PRECIPITATION ON TUESDAY AS THE COLDER AIR MOVES
IN. ON THE ORDER OF A TENTH OR TWO OF AN INCH LIQUID EQUIVALENT.

THE CORE OF THE COLDEST AIR SLIDES ACROSS UPSTATE NEW YORK AND NEW
ENGLAND WITH OUR FORECAST AREA IN AN AREA FAVORABLE FOR ANY
POSSIBLE ALBERTA CLIPPER TRACKS.

MREF PLUMES AND LONG RANGE ENSEMBLES STILL INDICATING A
PRECIPITATION EVENT FOR NEW YEARS EVE. CURRENT FORECAST TRACK OF
LOW PRESSURE SYSTEM REMAINS OFFSHORE BUT THAT IS RIGHT WHERE WE
WANT FOR THE POTENTIAL FOR ACCUMULATING SNOW. THAT IS BECAUSE THE
INHERENT WESTWARD TREND OF THE MODEL WITH TIME SHOULD EVENTUALLY PLACE
THE STORM ALONG THE EASTERN SEABORD. WE WILL SEE IF THE RECENT
WESTWARD AGJUSTMENT DOES TAKE PLACE FOR THIS EVENT.

ALL IN ALL...A SEASONABLY COOL WEEK WITH CHANCES FOR LIGHT
ACCUMULATING SNOW THROUGH THE WEEK.

&&

.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
LGT RAIN & DRIZZLE SLOLY RETREATING NEWD ACROSS CNTRL & ERN PA
DURG EVE. IFR FOG AND LOW CIGS RMNG OVR MUCH OF CNTRL PA OVRNGT.
PRTL CLRG OCRG OMTN AND NRN SXNS WITH MVFR CIGS. SUNDAY...VFR WITH LGT
W-SW SFC WINDS WITH UNL VSBY AND FQT CIGS AOA 4 THSD FT. SNSHWRS
AND AREA OF LGT SNW MOVG W-E ACROSS AREA SUNDAY NGHT LWRG CONDS
AOB IFR IN SNW AHEAD OF ARCTIC FRONT PASSAGE.

OUTLOOK... MON-TUE...BRISK NW FLOW. MVFR/IFR WEST WITH FREQ SNOW
SHOWERS. CNTRL/EAST VFR/MVFR WITH SCATTERED SNOW SHOWERS.
WED...VFR. THU...MVFR-IFR IN AREAS OF LGT SNW.

&&

.HYDROLOGY...
RIVER LVLS CONTINUE TO RESPOND TO THE RAIN AND SNOWMELT...WITH 
LATEST MARFC GUIDANCE CONT TO INDICATE MODEST RISES TO OCCUR OVER
SOUTHEAST PA. ADDITIONAL QPF FROM AREAS LIGHT RAIN AND DRIZZLE
WILL BE NEGLIGABLE...WHICH SHUD HELP TO SLOW DOWN ANY MINOR
FLOODING ISSUES TONIGHT. SHERMANSDALE AT SHERMAN CREEK IS ABOVE
CAUTION STAGE AND WILL DROP BELOW BY LATE TONIGHT AS A RESULT.

&&

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

&&

$$
SYNOPSIS...DEVOIR
NEAR TERM...DEVOIR
SHORT TERM...DEVOIR
LONG TERM...TYBURSKI
AVIATION...BUDD
HYDROLOGY...