Area Forecast Discussion
Issued by NWS State College, PA

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000
FXUS61 KCTP 161508
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
1108 AM EDT TUE SEP 16 2014

.SYNOPSIS...
HIGH PRESSURE WILL BUILD IN FROM THE MIDWEST TODAY AND TONIGHT. A
STRING OF MOSTLY SUNNY DAYS AND CHILLY NIGHTS WILL FOLLOW FOR THE
REST OF THE WEEK. TEMPERATURES WILL BE SLIGHTLY BELOW NORMAL ALL
WEEK.

&&

.NEAR TERM /UNTIL 8 PM THIS EVENING/...
HIGH PRESSURE OVER THE MIDWEST AND NORTHWESTERLY WINDS RESULTING
IN A TYPICAL POST-COLD FRONTAL LOOK TO THE SATELLITE PICS.
WHILE DOWNSLOPE WARMING/DRYING IS EATING UP THE CLOUDS AS THEY
TRY TO GET INTO THE SE...THE LARGE BREAKS IN THE CLOUDS OVER THE
LAST TWO HOURS ARE QUICKLY CLOSING UP. WILL THEREFORE MAKE MUCH OF
THE AREA P/C FOR THE NEXT FEW HOURS...THEN CLEAR IT OUT QUICKLY
BY/AROUND SUNSET. TEMPS ON TRACK AND SHOULD ADD ANOTHER 5-6F THEN
GET STUCK AS THE CLOUDS AND COLD ADVECTION HALT THE RISE.

&&

.SHORT TERM /8 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
THE PRIMARY CONCERN FOR THIS PERIOD IS THE POTENTIAL FOR SOME
FROST LATE TONIGHT AND EARLY WEDNESDAY /AND PERHAPS EVEN A FEW
LOCATIONS WITH TEMPS NEAR FREEZING/ ACROSS THE NORTHERN MTNS.

LATEST...00Z MAV NUMBERS AND 08Z GFS LAMP GUIDANCE REMAIN AT THE
COLDER END OF ALL GUIDANCE...AND HAVE BFD RIGHT AROUND 32. MAINLY
CLEAR SKIES AND LIGHT WINDS...ALONG WITH HIGH HEIGHTS AND LOW
DEWPOINTS /WITH PWS AOB 0.50 INCH/ WILL BE THE MAIN CULPRITS
LEADING TO THE POSSIBLE FROST UP NORTH.

ELSEWHERE...TEMPS WILL BE CHILLY...BUT MOST LOCATIONS SHOULD
SEE TEMPS SETTLE INTO THE U30S AND 40S BY SUNRISE WED.

AN EAST/WEST RIDGE OF HIGH PRESSURE WILL BUILD OVER THE MID
ATLANTIC REGION AND OHIO VALLEY REGION WEDNESDAY...ACCOMPANIED BY
ABUNDANT SUNSHINE...LIGHT WIND...AND AFTERNOON MAX TEMPS NEAR TO
SLIGHTLY BELOW NORMAL.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
UPPER TROUGH SHARPENS OVER QUEBEC WED NIGHT/THU...PUSHING A WEAK
FRONTAL BOUNDARY SOUTH TOWARD PA ON THU. THIS FRONT WILL CONTINUE
TO WEAKEN AS IT EDGES SOUTHWARD...BUT A WEAK SHORTWAVE WILL SLIDE
OVERHEAD FROM THE MIDWEST. THIS WILL BRING AN INCREASE IN CLOUDS
COVER ALONG WITH JUST A CHANCE FOR A SPRINKLE. NORTHERN PA WILL
GET A REINFORCING SHOT OF COOLER AIR...KEEPING HIGHS IN THE UPPER
50S TO LOWER 60S.

HIGH PRESSURE THEN BUILDS ACROSS THE GREAT LAKES INTO A 1030MB
HIGH OVER NEW ENGLAND BY FRI...BRINGING A PERIOD OF QUIET WEATHER
AND UNSEASONABLY COOL TEMPERATURES. MORNING LOWS IN THE 30S ARE
LIKELY THU NIGHT/EARLY FRIDAY /ESPECIALLY IF SKIES CLEAR OUT AS
ANTICIPATED/.

00Z GEFS AND 03Z SREF TEMP PLUMES SUGGEST THAT THE SCATTERED
FROST THREAT MAY EXTEND ACROSS THE CENTRAL VALLEYS...AND EVEN INTO
THE TYPICALLY COLD RURAL LOCATIONS OF SCENT PENN. THE HIGH TEMPS
FRI WILL BE MAINLY IN THE 60S AS NW FLOW CONTINUES.

RETURN FLOW BEGINS WEAKLY FRI NIGHT...TAKING A LITTLE OF THE BITE
OUT OF OVERNIGHT LOWS /THOUGH STILL CHILLY WITH READINGS MAINLY IN
THE 40S/. BUT THIS WILL BEGIN A WARMING TREND FOR THE WEEKEND.
TEMPS SAT INTO SUN WILL BE 5-8F WARMER THAN FRI...WITH HIGHS
APPROACHING 80F IN THE SE. LOWS WILL BE NOTICEABLY MILDER AS WELL
AS LOW LEVEL MOISTURE INCREASES IN STRENGTHENING SW FLOW.

HEADING INTO SUNDAY...DEEPENING LOW CENTERED WELL TO OUR NORTH
AS A TROUGH AXIS ROTATES THROUGH THE GREAT LAKES WILL BRING PLENTY
OF CLOUDS AND A CHANCE FOR SHOWERS. MODELS STILL SHOWING LARGE
DIFFERENCES ON EVOLUTION OF THIS SYSTEM...WITH GFS MORE
PROGRESSIVE AND ECMWF ACTUALLY BRINGING A SECOND WAVE AROUND THE
BACKSIDE OF THE TROUGH AND DEVELOPING A STUBBORN CLOSED UPPER LOW
OVER THE REGION. FOR NOW WILL SPLIT THE DIFFERENCE AND HOLD ON TO
MENTION OF SHOWERS INTO MON ALONG WITH ANOTHER SHOT OF COOLER AIR
AND SEE HOW THIS PLAYS OUT OVER NEXT COUPLE OF DAYS.

&&

.AVIATION /15Z TUESDAY THROUGH SATURDAY/...
SOME LIGHT SHOWERS DUE TO THE MOIST NORTHWESTERLY FLOW BEHIND THE
FRONT HAVE DEVELOPED OVER THE NW MTNS. THESE SHOULD CONTINUE
THROUGH MID MORNING...WITH MVFR CIGS AND VSBYS CONTINUING AT BFD
THROUGH 13Z. JST IS IFR DUE TO LOW STRATO CU WITH LNS PROBABLE AT
MVFR AS WELL. THESE LOW CLOUDS SHOULD LIFT AS THE WINDS SHIFT TO
THE NORTHWEST AFTER 13Z CONDITIONS SHOULD THEN BECOME VFR. BY MID
TO LATE MORNING THE COLD FRONT MOVES EAST OF THE AREA AND THE
WINDS WILL SHIFT TO THE NORTHWEST. ONCE THE INVERSION LIFTS GUSTY
NORTHWESTERLY FLOW REMAINS PROBABLE...THOUGH MAX GUSTS SHOULDN/T
EXCEED 20MPH. ANY GUSTY WINDS SHOULD SUBSIDE AROUND SUNSET...WITH
MILDER...VFR CONDITIONS SETTLING IN THIS AFTERNOON INTO TONIGHT.

SOME POTENTIAL FOR FOG TUESDAY NIGHT EXISTS...AS HIGH PRESSURE
BUILDS OVER THE AREA.

MAINLY DRY CONDITIONS THE REST OF THE WEEK...AS HIGH PRESSURE
PREVAILS.

OUTLOOK...

WED-SAT...MAINLY VFR CONDITIONS.

&&

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

&&

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


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