Area Forecast Discussion
Issued by NWS State College, PA

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FXUS61 KCTP 191252
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
752 AM EST FRI DEC 19 2014

.SYNOPSIS...
HIGH PRESSURE OVER THE GREAT LAKES WILL SLIDE EAST INTO
PENNSYLVANIA THIS WEEKEND. A DEEP UPPER TROUGH AND ASSOCIATED SFC
LOW WILL LIFT NORTHEAST THROUGH THE GREAT LAKES DURING THE MIDDLE
OF NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LINEAR FEATURE ON RADAR LOOP RUNNING FROM KYNG TO KDUJ AT 11Z
APPEARS TO BE SFC TROUGH...WHICH IS PROGGED BY NR TERM MDLS TO
WASH OUT AS IT PRESSES SOUTH THIS MORNING. RIBBON OF HIGHER LOW
LVL MOISTURE ALONG AND IN ADVANCE OF THIS FEATURE HAS BEEN
SUPPORTING SPOTTY LGT SNOW/FZDZ ACROSS THE ALLEGHENY MTNS THIS
MORNING. WINT WX ADV...WHICH HAS BEEN IN EFFECT ACROSS THE N
MTNS...WILL EXPIRE AT 12Z AS FOCUS OF FREEZING PRECIP SHIFTS
SOUTH INTO THE LAUREL HIGHLANDS.

OROGRAPHIC FORCING OF SHALLOW LYR OF MOISTURE SHOULD CONTINUE TO
PRODUCE A BIT OF LGT SNOW OR FZDZ ACROSS CAMBRIA/SOMERSET
COUNTIES THRU ARND MIDDAY. HOWEVER...GIVEN THE VERY LGT NATURE OF
THE PRECIP AND THAT SOME IS FALLING AS SNOW...HAVE OPTED TO COVER
WITH AN SPS RATHER THAN A WSW. SFC OBS HAVE BEEN INDICATING BOTH
-SHSN AND -FZDZ AND MDL SOUNDINGS INDICATE BORDERLINE CLOUD TOP
TEMPS OF ARND -10C...SO WILL CONTINUE TO FCST SCT -SHSN AND PATCHY
-FZDZ OVR THE LAUREL HIGHLANDS THIS AM.

OTHERWISE...ARRIVAL OF DRIER AIR IN WAKE OF TROF SHOULD PRODUCE
PARTIAL CLEARING LATER TODAY...ESP WHERE WEST WIND DOWNSLOPES THE
MTNS ACROSS THE SUSQ VALLEY.

MAX TEMPS SHOULD BE SIMILAR TO THURSDAY...WITH U20S OVR THE
HIGHEST TERRAIN OF THE ALLEGHENIES...TO THE U30S ACROSS THE LOWER
SUSQ VALLEY.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
HIGH PRESSURE AND ASSOC DRIER AIR MASS WILL BUILD IN FROM THE GRT
LKS TONIGHT...PROVIDING THE AREA WITH FAIR WX. FOR MUCH OF CENTRAL
PA...TONIGHT SHOULD FEATURE MCLEAR SKIES. HOWEVER...LOW LVL
MOISTURE TRAPPED BENEATH INVERSION MAY RESULT IN PERSISTENT
STRATOCU ACROSS THE LAUREL HIGHLANDS THIS EVENING.

WAA ALOFT IN ADVANCE OF SHORTWAVE LIFTING OUT OF THE MISS VALLEY
WILL LIKELY SPREAD SOME THIN CIRRUS INTO THE REGION ON SATURDAY.
HOWEVER...ALL MDL DATA SUPPORTS A DRY DAY WITH SFC RIDGE AND LOW
PWAT AIRMASS OVR THE STATE. MAX TEMPS SHOULD BE FAIRLY CLOSE TO
SEASONAL NORMS IN THE 30S.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
HIGH PRESSURE WILL SHIFT SLOWLY EASTWARD FROM THE GREAT LAKES
INTO NORTHERN NEW ENGLAND BY 12Z MONDAY. A MOISTURE-STARVED NRN
STREAM SHORTWAVE SHOULD PRODUCE A PERIOD OF CLOUDINESS SAT
NIGHT...BUT LIKELY NOT PRODUCE ANY PRECIP. LATEST MDL SOUNDINGS
POINT TOWARD A RELATIVELY BRIGHT SUNDAY IN THE WAKE OF THIS
FEATURE WITH NEAR SEASONAL TEMPS. SPLIT FLOW REGIME ACROSS THE
LOWER 48 WILL TRANSITION TO A HIGHLY AMPLIFIED PATTERN BY EARLY
NEXT WEEK ACROSS THE LOWER 48...WITH A DEEP NEGATIVELY TILTED
TROUGH EVOLVING OVER THE EASTERN 1/3RD OF THE CONUS.

THE MODELS SEEM TO BE FORMING A CONSENSUS ON THE PESKY LOW
THAT REFUSES TO BE WELL FORECAST...LIFTING IT SLOWLY FROM FL
PANHANDLE NNEWD JUST OFF THE EAST COAST SUN-MON ALONG A LOW LEVEL
BAROCLINIC ZONE THAT MAY NOT BUDGE PAST THE GULF STREAM AS THE
FLOW ALOFT TURNS SOUTHWESTERLY/PARALLEL TO THE COASTAL FRONT.
INCREASED POPS FOR MONDAY OVER THE SE BASED ON MULTI-MODEL/WPC
BLEND. COMPLEX SFC PATTERN WITH SOME HINTS AT LOW LEVEL CAD ALONG
WITH WAA ALOFT VIA SLY FLOW COULD MAKE FOR A MESSY MIXED PTYPE
TRANSITION.

AN INTENSE TRIPLE POINT SYSTEM DEVELOPING ON DEC 23-24 WILL
LIKELY STEAL THE HEADLINES GIVEN ITS TIMING AND LARGE PORTION OF
REAL ESTATE THAT WILL BE AFFECTED. WHILE THE DETAILS REMAIN
UNCLEAR AT THIS POINT...TEMPERATURES SHOULD BE WARM ENOUGH TO
SUPPORT RAIN ON THE FRONT SIDE OF THE SYSTEM BEFORE BRISK WNW
WINDS DRIVE STRONG CAA EAST OF THE APPALACHIANS. THE TIMING OF THE
COLD/OCCLUDED FRONT WILL BE KEY FOR PRECIPITATION TRANSITION FROM
RAIN TO SNOW SHOWERS. AS THE SYSTEM SPINS UP INTO EASTERN
CANADA...THE STRONG CAA CIRCULATING THROUGH THE GREAT LAKES AND OH
VLY SHOULD LEAD TO LAKE EFFECT/UPSLOPE/WRAP AROUND SNOW SHOWERS
OVER THE WESTERN ALLEGHENIES BY CHRISTMAS DAY. A PERIOD OF STRONG
GUSTY WINDS ARE HIGHLY PROBABLE AS THE DYNAMIC SYSTEM INTENSIFIES
SHIFTING NWWD FROM NEW ENGLAND INTO ONTARIO/QUEBEC.

THE TAKE HOME MESSAGE IS THAT A VOLATILE PERIOD OF WEATHER WILL
IMPACT THE AREA THROUGH CHRISTMAS DAY WITH POTENTIAL WIND...RAIN
AND SNOW IMPACTS ALL ON THE TABLE. STAY TUNED.

&&

.AVIATION /13Z FRIDAY THROUGH TUESDAY/...
SFC TROUGH DROPPING SOUTHWARD THIS MORNING WILL GRADUALLY WASH
OUT. RIBBON OF HIGHER LOW LVL MOISTURE ALONG AND IN ADVANCE OF
THIS FEATURE HAS BEEN SUPPORTING SPOTTY LGT SNOW/FZDZ ACROSS THE
ALLEGHENY MTNS THIS MORNING...BRINGING ICING CONCERNS FOR
AVIATION INTERESTS. IFR CONDITIONS ONGOING AT KBFD-KJST WITH
WIDESPREAD MVFR ELSEWHERE.

OROGRAPHIC FORCING OF SHALLOW LYR OF MOISTURE SHOULD CONTINUE TO
PRODUCE A BIT OF LGT SNOW OR FZDZ AROUND KJST THROUGH LATE MORNING.
OTHERWISE...ARRIVAL OF DRIER AIR IN WAKE OF TROF SHOULD PRODUCE
GRADUALLY LIFTING CIGS WITH PARTIAL CLEARING LATER TODAY...ESP
WHERE WEST WIND DOWNSLOPES THE MTNS ACROSS THE SUSQ VALLEY AND SE
HALF OF CWA. NORTHWEST WINDS WILL BE AROUND 10 KTS WITH HIGHER
GUSTS.

HIGH PRESSURE BUILDS IN TONIGHT...WITH MAINLY VFR CONDITIONS. SOME
MVFR CIGS MAY DEVELOP AGAIN OVER THE NW MTNS AT KBFD. AND LIGHT
WINDS MAY PRODUCE SOME LOCAL FOG RESTRICTIONS IN SPOTS.

OUTLOOK...

SAT-SUN...NO SIG WX EXPECTED.

MON...LOW CIGS WITH LGT RAIN/SNOW POSSIBLE. BECOMING BREEZY.

TUE...LOW CIGS WITH RAIN LIKELY. BREEZY.

&&

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

&&

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



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