Area Forecast Discussion
Issued by NWS State College, PA

Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS61 KCTP 271246
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
746 AM EST THU NOV 27 2014

.SYNOPSIS...
HAPPY THANKSGIVING FROM THE NATIONAL WEATHER SERVICE IN STATE
COLLEGE.

A WEAK UPPER AIR DISTURBANCE WILL KEEP CLOUDS AND THE CHANCE OF A
FEW LIGHT SNOW SHOWERS IN THE FORECAST TODAY AND FRIDAY.
TEMPERATURES WILL BEGIN TO MODERATE THIS WEEKEND AS HIGH PRESSURE
MOVES OFF THE SE COAST.

&&

.NEAR TERM /THROUGH TONIGHT/...
RADAR IS SHOWING LIGHT RETURNS PRETTY MUCH MEANDERING ABOUT OVER
MUCH OF NORTHERN PA AS OF 6AM. MOST SURFACE STATIONS ARE NOT
OBSERVING PRECIP...SO THE FORECAST LOOKS ON TRACK FOR ONLY LIGHT
SNOW SHOWERS OR FLURRIES.

AS THE STORM PULLS AWAY OFF THE NEW ENGLAND
COAST...WE WILL BE LEFT TO DEAL WITH THE UPPER TROF THAT IS
LAGGING BACK THROUGH THE GR LAKES. THIS WILL KEEP PLENTY OF CLOUD
COVER AND SCATTERED LIGHT SNOW SHOWERS IN THE FORECAST. WITH
GENERALLY WEAK NORTHWESTERLY FLOW...THE PRECIP SHOULD FAVOR THE
USUAL WESTERN AND NORTHERN HIGH TERRAIN...TENDING TO DRY OUT AS
ACTIVITY DOWNSLOPES INTO CENTRAL AND SOUTHERN AREAS.

HIGHS TODAY WILL RANGE FROM THE UPPER 20S OVER THE NORTH TO MID
30S OVER THE SOUTH...WHICH WILL AVERAGE AROUND 10 DEG BELOW
NORMAL.

BIGGEST QUESTION FOR LATER TODAY INTO THE OVERNIGHT WILL BE
WHETHER A PERIOD OF MORE ORGANIZED LAKE EFFECT CAN GATHER ITSELF
OVER NWRN AREAS. DEEP LAYER FLOW DOES LOOK FAVORABLE FOR A TIME
TONIGHT...BUT RELATIVELY SHORT OVER-LAKE TRAJECTORIES SHOULD
LIMIT SNOWFALL TO MAINLY SUB ADVISORY LEVELS.

I USED A MOS BLEND FOR THE OVERNIGHT LOWS IN THE 20S. THESE WILL
BE SEVERAL DEG BELOW NORMAL.

&&

.SHORT TERM /FRIDAY/...
INVERSION HEIGHTS ARE EXPECTED TO LOWER FRIDAY WHICH SHOULD PUT A
DAMPER ON ANY OF THE BEST DEVELOPED LAKE EFFECT BANDS...BUT CLOUDS
AND PERHAPS A FEW SNOW SHOWERS WILL REMAIN POSSIBLE OVER THE
NORMAL WESTERN AND NORTHERN LOCATIONS. THE BEST CHANCES WILL BE
IN THE MORNING...WITH BRIGHTENING SKIES LIKELY IN THE AFTERNOON.

HIGHS WILL BE A FEW DEG COOLER THAN TODAY AS THE CORE OF THE POST
FRONTAL COLD AIR SETTLES OVERHEAD.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
ANOMALOUSLY LOW HEIGHTS OVER THE EASTERN US EARLY IN THE PERIOD
WILL FLATTEN OUT INTO A BROAD ZONAL FLOW DURING THE WEEKEND. THIS
WILL PROMPT A WARM-UP AS THE CYCLONE TRACK SHIFTS TO OUR NORTH AND
HIGH PRESSURE MOVES OFF TO OUR SOUTHEAST.

THE COLD POST FRONTAL AIRMASS WILL BEGIN MODERATING BY
SATURDAY...WITH READINGS REACHING THE MILD RANGE BY SUNDAY.

MODELS WHICH WERE IN DECENT AGREEMENT ON THE APPROACH OF A FRONT
FOR MONDAY...NOW HAVE DIFFERENCES IN DROPPING A WEAK COLD FRONT
THROUGH THE AREA EARLY NEXT WEEK. THE GFS/GEFS ARE FASTER AND HAVE
HIGH PRESSURE BUILDING IN FOR MONDAY...WHILE THE ECMWF SLOWS ITS
FRONTAL PASSAGE DOWN BY AT LEAST 12 HOURS. GIVEN THE FLAT FAST
FLOW...SUCH DIFFERENCES ARE NOT UNEXPECTED. WHILE THE FRONT WILL
REPRESENT THE BEST CHANCE FOR ORGANIZED PRECIP AND THE PASSAGE
TIME IS UNCERTAIN...ZONAL FLOW WILL MAKE FOR A LACK OF MOISTURE
KEEPING QPF BE ON THE LIGHT SIDE.

ONE AREA OF POSSIBLE CONCERN COULD BE THE EXPECTED DEVELOPMENT OF
SOME LIGHT WARM ADVECTION PRECIP SATURDAY NIGHT INTO SUNDAY
MORNING. TEMPS ALOFT WARM RAPIDLY...AND I KEPT FORECAST SURFACE
MINS MAINLY ABOVE FREEZING. BUT IF WE END UP A FEW DEG COOLER...WE
COULD SEE A PERIOD OF SOME LIGHT ICING UNTIL TEMPERATURES CAN
RECOVER SUNDAY.

THE EXPECTED WARM UP OVER THE WEEKEND INTO EARLY NEXT WEEK SHOULD
GO A LONG WAY TOWARD ERASING THE SNOW THAT BLANKETED THE REGION
YESTERDAY.

&&

.AVIATION /12Z THURSDAY THROUGH MONDAY/...
WEAK RIDGING AT THE SFC AND ALOFT /IN THE WAKE OF YESTERDAY/S
SNOWSTORM/ WILL BE OVER THE REGION INTO THIS AFTERNOON AS A WELL-
DEFINED UPPER DISTURBANCE PASSES HARMLESSLY TO THE SOUTH OF PENN
AIRFIELDS TODAY. EXPECT THIS

AFTER THE PASSAGE OF THE UPPER SHORTWAVE...THE FEW DEG C INVERSION
BETWEEN 4-5 KFT AGL...AND THE RELATIVELY LIGHT NW BENEATH THIS
STABLE LAYER...WILL MAKE FOR A RATHER HAZY/STAGNANT MID TO LATE
MORNING. THE NW BREEZE WILL PICK UP A BIT AFTER 15Z...HELPING TO
MIX OUT AND ERODE THE LOWER STRATUS BASES ACROSS MUCH OF THE
ALLEGHENIES. HOWEVER...MOIST UPSLOPE FLOW /NEARLY ORTHOGINAL TO
THE WESTERN PA RIDGES/...AND DEEPENING OF THE COLD AIR WILL LEAD
TO A GRADUAL INCREASE IN SNOW SHOWERS THIS AFTERNOON AND EVENING
WITH PERIODS OF IFR/LIFR LIKELY AT KBFD AND KJST AFTER 21Z.

VFR WILL CONTINUE ACROSS THE REGION NEAR AND SE OF A LINE FROM
KAOO TO KUNV AND KIPT...WHILE MVFR WILL BE THE RULE ACROSS MUCH OF
THE ALLEGHENY MTNS OF NRN AND WRN PENN. PATCHY LIGHT FREEZING
DRIZZLE IS POSSIBLE AT KJST FOR THE NEXT FEW HOURS /THROUGH ABOUT
15Z/ AS CLOUD TEMPS HOVER IN THE MINUS 6 TO MINUS 8 DEG C RANGE.

AFTERWARD...EXPECT PLENTY OF STRATO CU /TOPPED BY A LAYER OR TWO
OF ALTOCU AND CIRRUS/ AND RELATIVELY LIGHT NW WINDS THROUGH 18-21Z
TODAY WITH JUST SOME ISOLATED TO SCATTERED SNOW SHOWERS ACROSS THE
NW MTNS AND LAUREL HIGHLANDS /FROM KBFD TO KJST/.

SOME LAKE EFFECT -SHSN ARE FCST TO DEVELOP LATE THIS AFTERNOON
THROUGH TONIGHT OVER THE WRN 1/3 WHERE REDUCED CONDS ARE LKLY TO
PERSIST. COINCIDING WITH THE SNOW SHOWERS...WILL BE AN INCREASE IN
THE NW WINDS AND ASSOCIATED GUSTS.

LATE DAY/NIGHT-TIME WINDS SHOULD GUST IN EXCESS OF 20KTS ACROSS
THE MTNS OF WRN PENN...WHILE GUSTS ELSEWHERE WILL LIKELY BE IN
THE MID TO UPPER TEENS - MAINLY THIS AFTERNOON AND EVENING.

OUTLOOK...

TONIGHT...IFR/MVFR WITH OCNL -SHSN WRN 1/3. VFR TO MVFR CIGS
CNTRL/EAST.

FRI...AM MVFR/-SHSN NW...OTHERWISE BCMG VFR.

SAT-SUN...MAINLY VFR. ISOLD -SHRA PSBL.

MON...COLD FROPA. MAINLY VFR. SCT -SHRA PSBL.

&&

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

&&

$$
SYNOPSIS...LA CORTE
NEAR TERM...LA CORTE
SHORT TERM...LA CORTE
LONG TERM...LA CORTE
AVIATION...LAMBERT



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.