Area Forecast Discussion
Issued by NWS State College, PA

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FXUS61 KCTP 251505
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
1005 AM EST TUE NOV 25 2014

.SYNOPSIS...
HIGH PRESSURE WILL BUILD NORTHEAST FROM THE OHIO RIVER VALLEY
TODAY WITH FAIR AND COOLER CONDITIONS. A STORM SYSTEM WILL FORM
ALONG THE SOUTHEASTERN COASTLINE OF THE UNITED STATES AND MOVE UP
ALONG OR JUST OFF THE EASTERN SEABOARD WEDNESDAY...BRINGING A
CHANCE OF SIGNIFICANT SNOW TO SOUTHERN AND EASTERN PA WEDNESDAY.
ANOTHER SHOT OF COLDER AIR WILL FOLLOW FOR NEXT WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
SATELLITE CONTINUES TO SHOWS SHIELD OF MID-HIGH CLOUDS RACING NE
OVER THE REGION IN RESPONSE TO A SHEARING OUT SHORTWAVE EMBEDDED
IN THE FAST SWLY FLOW ALOFT. REGIONAL RADAR SHOWS THAT PRECIP IS
REMAINING WELL SOUTH AND EAST OF THE LOCAL AREA.

FOR TODAY WE WILL SEE A WEAK RIDGE OF HIGH PRESSURE NOSE IN FROM
THE OHIO VALLEY. I WENT FOR PARTLY TO MOSTLY SUNNY SKIES BUT WILL
NOT BE SURPRISED IF A FAIR AMOUNT OF HIGH CLOUDINESS PREVAILS AS
WE STAY UNDER A FAST SWLY FLOW ALOFT.

IT`S GOING TO TAKE A WHILE FOR THE COLD AIR TO FILTER IN TODAY...SO
MUCH OF THE SERN HALF OF MY FCST AREA WILL REMAIN UNSEASONABLY
MILD IN THE MID TO UPPER 50S...WHILE THE NW WILL BE COOLER IN THE
30S.

MODELS ARE IN GOOD AGREEMENT TO DEVELOP A NEW STORM ALONG THE
GA/SC COAST IN RESPONSE TO A POTENT SHORTWAVE APPROACHING FROM
THE MISSISSIPPI VALLEY. THE SYSTEM ALOFT TAKES ON A NEG TILT AS
IT MOVES UP THE EASTERN SEABOARD...WITH THE SURFACE LOW MADE TO
TRACK ALONG THEN JUST OFFSHORE OF THE EAST COAST WEDNESDAY. TIMING
SUGGESTS PRECIP OVERSPREADING THE SOUTHERN TIER COUNTIES BEFORE
DAYBREAK WEDNESDAY. TEMPS ALOFT AND ON THE SURFACE SUGGEST THAT
PRECIP STARTING OVER SOUTHERN AREAS LATER TONIGHT WILL LIKELY BE
AT LEAST A MIX OF RAIN AND SNOW WITH LIGHT SNOW ON THE NORTHERN
EDGE.

&&

.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
THE MAIN SHOW WILL OCCUR WEDNESDAY AS THE STORM DEVELOPS AND
INTENSIFIES AS IT TRACKS FROM THE CAROLINA COAST TO OFF THE NJ
COAST BY WED EVENING. THE TRACK IS CLOSE ENOUGH TO PLACE MY
EASTERN ZONES UNDER THE THREAT FOR WARNING CRITERIA SNOWS...WITH
AMOUNTS OF 3-6" POSSIBLE EVEN BACK INTO THE LAURELS. AS A RESULT
I EXTENDED THE WATCH TO INCLUDE SOMERSET AND CAMBRIA
COUNTIES...GIVEN THE EXPECTATIONS OF A HIGH IMPACT SNOWFALL ON A
WHAT IS TRADITIONALLY ONE OF THE MOST HEAVILY TRAVELED DAYS OF THE
YEAR.

LATEST WWD GRAPHICS SHOW A SWATH OF 6-8 SNOWS OVER THE SERN 1/3
OR SO OF MY FCST AREA. THIS IS NOT SIGNIFICANTLY DIFFERENT THAN
THE SREF THREAT PAGE THAT SHOWS A SIMILAR ORIENTATION OF WARNING
SNOWS FROM THE NRN PART OF THE STATE INTO MY SOUTH-CENTRAL
MOUNTAINS...NUDGING SOMERSET AND CAMBRIA COUNTIES. I USED A BLEND
OF MODEL QPF WHICH FAVORS SERN ZONES WITH HIGHEST AMOUNTS...WHICH
MAKES SENSE GIVEN THE EXPECTED TRACK JUST OFFSHORE RATHER THAN
CLOSER TO THE COAST WHICH IS PREFERABLE FOR LOCAL SNOW CROWS. I
TRIED TO SIMILARLY PAINT THE BEST CHANCE OF WARNING SNOWS OVER
THIS SERN 1/3 OR SO BACK INTO THE AREAS FAVORED BY THE SREF THREAT
PAGE AND WWD FORECAST. I`M NOT AS CONFIDENT ABOUT SIG SNOWS UP
INTO CENTRAL PA GIVEN THE LACK OF A SIG EASTERLY LOW LEVEL WIND
ANOMALY IN THE ENSEMBLES...BUT FOR IMPACTS I CAN SEE AN ADVISORY
BEING NEEDED SO NO CHANGES WERE MADE TO THE WATCH ON THE NORTHERN
EDGES.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
A SHOT OF COLD AIR WILL MOVE INTO THE REGION FOR THE HOLIDAY AND
CONTINUE THROUGH FRIDAY. THIS SHOULD GENERATE THE USUAL POST
FRONTAL LAKE AND OROGRAPHICALLY ENHANCED SNOW SHOWERS IN THE WAKE
OF THE DEPARTING STORM SYSTEM WITH WESTERN AND NORTHERN AREAS
SEEING THE BEST CHANCE OF SCATTERED LIGHT SNOWS...WHILE THE REST
OF THE REGION SEES LITTLE OR NO SNOW SHOWER ACTIVITY AT ALL.

A BROAD WSW FLOW ALOFT WILL MAKE THE NEXT COLD SHOT TEMPORARY
WITH WARMER AIR BEGINNING TO MAKE A RETURN BY SATURDAY. HIGHS WILL
RETURN TO NEAR OR EVEN A TICK ABOVE NORMAL BY THE WEEKEND BEFORE
COOLER AIR APPROACHES AGAIN FOR EARLY NEXT WEEK.

&&

.AVIATION /15Z TUESDAY THROUGH SATURDAY/...
WHEN I DID THE 18Z TAFS YESTERDAY...WAS CONCERN ABOUT LOWER
SC INTO BFD. BEEN SOME IN BFD THE LAST FEW HOURS...BUT THEY
ARE ON THE EASTERN EDGE. DID HAVE SOME AT JST.

CENTRAL AREAS HAVE BKN250...WHILE AREAS TO THE EAST AND SOUTH
HAVE A THICKER CI DECK.

WILL ADJUST 15Z TAFS AS NEEDED...BUT MOST OF THE AREA WILL
BE VFR FOR MUCH OF THE DAY.

EARLIER DISCUSSION BELOW.

VFR WILL CONTINUE THROUGH THE FIRST HALF OF THIS EVENING.
CONDITIONS WILL DETERIORATE LATE TONIGHT AND THROUGH WEDNESDAY.
EXPECT MVFR CONDITIONS TO BEGIN THROUGH THE SOUTHEAST...AFFECTING
MDT AND LNS BETWEEN 06Z TO 12Z AND SPREADING NORTHWARD. A SMALL
BAND OF RAIN COULD OCCUR ON THE ONSET OF THE SYSTEMS ARRIVAL...BUT
SWITCH QUICKLY OVER TO SNOW. IFR RESRECTIONS SHOULD BE POSSIBLE AT
ALL TAF SITES EXCEPT BFD...WHICH WILL REMAIN VFR UNTIL THE SYSTEM
CREEPS NORTHWARD WEDNESDAY AFTERNOON. REDUCED CIGS AND VSBYS WILL
CONTINUE INTO WEDNESDAY EVENING.

OUTLOOK...

THU...AM FOG POSS SOUTH. EVENING -SHSN/REDUCED VSBYS POSS W MTNS.

FRI-SAT...NO SIG WX EXPECTED.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WATCH FROM WEDNESDAY MORNING THROUGH LATE
WEDNESDAY NIGHT FOR PAZ019-042-045-046-049>053.
WINTER STORM WATCH FROM LATE TONIGHT THROUGH WEDNESDAY EVENING
FOR PAZ024>028-033>036-056>059-063>066.

&&

$$
SYNOPSIS...LA CORTE
NEAR TERM...LA CORTE
SHORT TERM...LA CORTE
LONG TERM...LA CORTE
AVIATION...FITZGERALD/CERU/MARTIN


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