Area Forecast Discussion
Issued by NWS State College, PA

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000
FXUS61 KCTP 231509
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
1009 AM EST SUN NOV 23 2014

.SYNOPSIS...
LOW PRESSURE WILL MOVE FROM THE CENTRAL PLAINS TO THE WESTERN
GREAT LAKES BY MONDAY. A MILDER SOUTHERLY FLOW OF AIR AHEAD OF THE
STORM WILL BRING MODERATING TEMPERATURES THIS AFTERNOON AND
MONDAY...ALONG WITH A WIDESPREAD RAIN TONIGHT. A COLD FRONT WILL
CROSS THE REGION ON MONDAY. AN AREA OF LOW PRESSURE WILL MOVE
ALONG THE MID ATLANTIC COAST WEDNESDAY INTO THURSDAY...BRINGING A
CHANCE OF SNOW TO EASTERN HALF OF PENNSYLVANIA. ANOTHER SHOT OF
COLD AIR WILL FOLLOW FOR NEXT WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
10 AM UPDATE...
LIGHT SHRA CROSSING THE NRN TIER MOVING ACROSS AREAS WHICH ARE
ABOVE FREEZING...SO PROBLEMS ANTICIPATED THERE. COLDEST TEMPS
REMAIN FROM UNV-IPT/SEG...AND IT SHOULD REMAIN DRY THERE. MIXING
SHOULD BEGIN TO OCCUR IN THE SOUTHERN VALLEYS AS THE SUN IS AS
STRONG AND TEMPS SHOULD GET WELL INTO THE 50S. JST ALREADY 51F.
HIGH CLOUDS ARE STILL OFF TO THE SOUTH AND SHOULD ADVNACE
NORTHWARD STEADILY BUT NOT GET TOTALLY OPAQUE UNTIL CLOSER TO
SUNSET. TWEAKS TO TIMING OF PRECIP ONSET/QPF MADE TO MATCH WITH
ONSET TIMING PER NEWEST NEAR TERM MDLS.

PREV...
SPOTTY LIGHT SHOWERS WILL CONTINUE TO DIMINISH ACROSS THE
NORTHERN HALF OF CENTRAL PA THIS MORNING AS LLVL CONVERGENCE IS
LOST WITH THE EXIT AND DISSIPATION OF LLVL JET INTO SOUTHERN NEW
ENGLAND AND H5 SHORTWAVE RIDGING ARRIVING FROM THE OHIO VALLEY.
THE AMPLIFYING UPPER RIDGE WILL BRING SEVERAL HOURS OF FAIR
WEATHER TODAY LATER TODAY...ALONG WITH MILDER CONDITIONS...BEFORE
SOUTHERN STREAM WAVE OVER SOUTHEAST TX THIS MORNING APPROACHES THE
CENTRAL APPALACHIANS THIS EVENING...PUSHING WARM FRONT NORTHWARD
INTO THE COMMONWEALTH ON A STRONG 850 MB JET. BEST MOISTURE
CONVERGENCE WON`T ARRIVE UNTIL AROUND OR JUST AFT 00Z...AND A
SHIELD OF RAIN SHOULD ARRIVE FROM SOUTH TO NORTH BETWEEN 00Z AND
06Z.

WARM SECTOR WILL COVER CENTRAL PA LATE TONIGHT INTO MONDAY
MORNING...WITH SLOW MOVING COLD FRONT PUSHING INTO FAR WESTERN PA
EARLY MONDAY MORNING. BREEZY CONDS WILL BE SEEN IN THE WARM
SECTOR...BUT STRONGLY AGEOSTROPHIC STABLE FLOW WILL PRECLUDE THE
STRONGEST OF WINDS FROM MIXING TO THE SURFACE.

HIGHS TODAY WILL RANGE FROM 45 TO 50 ACROSS THE AREA. MINS TONIGHT
WILL RANGE THROUGH THE 40S IN THE WARM SECTOR.

&&

.SHORT TERM /MONDAY/...
STEADIEST RAINFALL SHOULD EXIT BY OR SHORTLY PAST 12Z...AS COLD
FRONT SLOWLY APPROACHES FROM THE OHIO VALLEY. STRONG WEST TO
SOUTHWEST FLOW BEHIND THE FRONT WILL HELP TO MIX DOWN SOME 25 TO
35 MPH GUSTS OVER WESTERN AND NORTHWEST PA. GOOD DOWNSLOPING
SHOULD ALLOW AREAS EAST OF THE ALLEGHENIES TO WARM THROUGH THE 50S
AND EVEN INTO THE LOWER 60S SOUTH AND EAST. STRONGEST BOUNDARY
LAYER COOLING WON`T TAKE PLACE UNTIL MONDAY NIGHT AND TUESDAY.

&&

.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
HIGHLY AMPLIFIED AND ACTIVE UPPER AIR PATTERN DEVELOPING NEXT
WEEK. THE 500MB CONFIGURATION WILL FEATURE ANOMALOUS RIDGING ALONG
THE WEST COAST AND IN THE WESTERN ATLANTIC WITH A FULL-LATITUDE
TROUGH CARVING OUT OVER THE CENTRAL AND ERN U.S.

RETURN OF WESTERLY FLOW BEHIND MONDAY FROPA WILL BRING SOME LIGHT
SNOW SHOWERS TO WESTERN HIGHER ELEVATIONS...BUT WSW TRAJECTORY IS
NOT FAVORABLE FOR LAKE EFFECT OVER THE NORTHWEST MOUNTAINS. CONFIDENCE
IS INCREASING IN COLDER TO BELOW AVG TEMPERATURES HEADING INTO
THANKSGIVING AND ESP THE WEEKEND AS THE GLOBAL MODELS AND
ENSEMBLES ARE SUGGESTING PERSISTENCE OF THE ERN CONUS MEAN TROUGH.

SATURDAY NIGHT/SUNDAY MORNING MODEL GUIDANCE CONTINUES TO SHOW A
LARGE DEGREE OF UNCERTAINTY IN THE POTENTIAL IMPACTS OF A WAVE
CURRENTLY COMING ONSHORE OVER WESTERN BRITISH COLUMBIA...WHICH IS
FORECAST TO SPAWN A COASTAL MID ATLANTIC LOW AND MOVE ALONG OF
JUST OFF THE COASTLINE WEDNESDAY INTO THU. THIS SITUATION WILL
CONTINUE TO BE WATCHED AS COLD AIR IN PLACE WILL LIKELY BE
SUFFICIENT TO SUPPORT SNOW AS PTYPE...AND TRAVEL DISRUPTIONS ARE
POSSIBLE ON WEDNESDAY SHOULD SOME OF THE WESTERN TRACK SOLUTIONS
VERIFY. 00Z SUN SUITE CONTS TO SHOW GEFS LARGELY FOCUSED ON A
MOSTLY OFFSHORE STORM TO AFFECT THE FISHES...WHILE OPERATIONAL
ECMWF SHOWS POTENTIAL FOR MORE WIDESPREAD INLAND SNOWFALL IMPACTS
ON WEDNESDAY AFTERNOON/NIGHT...ONE OF THE BUSIEST TRAVEL DAYS OF
THE YEAR. ANOTHER SHOT OF COLD AIR LOOKS POISED TO ARRIVE FOR NEXT
WEEKEND AFTER THE STORM EXITS.

&&

.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
CURRENTLY ALL TAF SITES ARE VFR AND SHOULD REMAIN SO THROUGH MOST
OF THE DAY. BUT MVFR MAY OCCUR FOR THE NEXT FEW HRS AT BFD AS SHRA
RUN THROUGH THEM OCCASIONALLY.

ANOTHER SYSTEM WILL MOVE IN TONIGHT...WITH PRECIPITATION POSSIBLE
AT ALL TAF SITES AFTER 00Z. IFR CONDITIONS ARE POSSIBLE AT THE
LOWER SUSQ TAF SITES WITH AT LEAST MVFR IF NOT IFR AT ALL
OTHERS...WITH PERIODS OF IFR POSSIBLE. LLWS WILL RETURN AT ALL TAF
SITES BETWEEN 01Z AND 05Z AND WILL CONTINUE INTO MONDAY MORNING.

OUTLOOK...

MON...MVFR/IFR WITH WIDESPREAD RAIN.

TUE...MVFR WITH SHSN WEST. VFR ELSEWHERE.

WED...IFR IN SN/SNRA EAST. MVFR/IFR IN SN CENTRAL. MVFR/VFR WEST.

THU...MVFR/IFR NW IN SHRA/SN.

&&

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

&&

$$
SYNOPSIS...DANGELO
NEAR TERM...DANGELO/DEVOIR
SHORT TERM...DEVOIR
LONG TERM...DEVOIR/RXR
AVIATION...DANGELO/CERU



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