Area Forecast Discussion
Issued by NWS State College, PA

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FXUS61 KCTP 182227
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
627 PM EDT THU SEP 18 2014

.SYNOPSIS...
HIGH PRESSURE WILL MAINTAIN FAIR AND SEASONABLE WEATHER THROUGH
EARLY SUNDAY. A FRONTAL SYSTEM WILL BRING A CHANCE OF SHOWERS TO
THE REGION ON SUNDAY...BEFORE ANOTHER LARGE AREA OF COOL HIGH
PRESSURE BRINGS ANOTHER PERIOD OF FAIR AND COOL WEATHER FOR MOST
OF NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
WEAK SFC COLD FRONT EVIDENT IN THE LAST FEW IMAGES OF VISIBLE LOOP
TRAVERSING SOUTHWARD FROM MY NORTHERN TIER COUNTIES EARLY THIS
EVENING. DIURNAL CUMULUS FIELD IS FADING RAPIDLY ACROSS CENTRAL
AND SOUTHERN AREAS. THE AFOREMENTIONED FRONT WILL CONTINUE TO DROP
SOUTHWARD THIS EVENING WITH LITTLE FANFARE. AT MOST IT WILL BE
ACCOMPANIED BY A SCT TO LCLY BKN LINE OF CUMULUS AND A SLIGHT
WIND SHIFT...ALONG WITH A FEW FAHREHNEIT DEGREE TEMPERATURE DROP.
AS THE SUN SETS...THIS WILL BE HARDLY NOTICEABLE.

TONIGHT WILL BY QUITE COLD BEHIND THE FRONT...WITH SCATTERED
FROST POSSIBLE ACROSS THE COLDEST VALLEYS ALONG THE NORTHERN PA
BORDER. CLOUDS ASSOCIATED WITH THE FRONTAL BOUNDARY MAY HOWEVER
LINGER ALONG THE NRN BORDER. ALSO..WITH THE SFC HIGH PRESSURE
CENTER LOCATED NORTH OF PA...ENOUGH EASTERLY GRADIENT MAY REMAIN
TO KEEP WINDS FROM GOING CALM. CURRENT GUIDANCE CONTINUES TO
INDICATE BORDERLINE TEMP/DEWPOINTS FOR WIDESPREAD FROST UP NORTH
ATTM...BUT GIVEN THE MENTIONED UNCERTAINTY AND AFTER COORDINATION
WITH SURROUNDING WFOS...HAVE DECIDED TO RUN WITH THE MENTION OF
SCATTERED FROST IN THE CURRENT FORECAST.

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/...
AS HIGH PRESSURE CENTER MOVES EAST OF THE NEW ENGLAND COAST
FRIDAY...SFC WINDS WILL TURN SERLY/SRLY HELPING DAYTIME TEMPS TO
RISE A FEW DEGREES HIGHER THAN TODAY. OTHERWISE EXPECT CONTINUED
RAIN FREE..MOSTLY SUNNY EARLY FALL-FEELING DAY ACROSS CENTRAL PA.

&&

.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
WARMER AIR AND HIGHER MOISTURE WILL ADVECT INTO THE REGION THIS
WEEKEND ON INCREASING SW FLOW AROUND A HIGH PRESSURE AREA
/RETREATING TO THE EAST/. AT THE SAME TIME...SHORTWAVE DROPPING
OUT OF CANADIAN ROCKIES WILL BEGIN TO CARVE OUT A TROUGH OVER THE
GREAT LAKES AS DEVELOPING SYSTEM APPROACHES PA FOR SUN/MON. THE
INITIAL RESULT WILL BE A PAIR OF ABOVE NORMAL TEMPERATURE DAYS
SAT-SUN WITH TEMPS MAINLY IN THE 70S...AND TAKING A RUN AT 80F IN
THE SE. WE/LL ALSO GET A BREAK FROM OUR RUN OF CHILLY OVERNIGHTS
AS LOWS REMAIN IN THE 50S FRI NIGHT TO AROUND 60F SAT NIGHT. A
PERIOD OF LOW/STRATUS AND PATCHY DRIZZLE IS POSSIBLE FOR A FEW
HOURS EARLY SATURDAY AS A WARM FRONTAL BOUNDARY SLIDES
NORTHWARD...OTHERWISE SHOWER ACTIVITY SHOULD REMAIN CONFINED TO
THE UPPER MIDWEST THROUGH EARLY SUNDAY.

THE CENTER OF THE APPROACHING LOW PRESSURE SYSTEM WILL REMAIN WELL
TO OUR NORTH...BUT A WEAK COLD FRONT WILL PUSH THROUGH PA SUNDAY
INTO SUN NIGHT. THIS WILL BE THE BEST CHANCE OF RAIN/SHOWERS
THROUGH DURATION OF THE EXTENDED FORECAST. THE LATEST ECMWF/GFS
GENERALLY AGREEING ON POTENTIAL FOR A TENTH TO POTENTIALLY A
QUARTER OF AN INCH OF QPF.

THE 500 HPA TROUGH BEHIND THE FRONT BOTTOMS OUT OVER THE REGION
MONDAY. THIS WILL KEEP MENTION FOR SCT INSTABILITY SHOWERS...MAINLY
IN HIGHER TERRAIN OF N/W CWA. COOLER AIR ON NW FLOW WILL GRADUALLY
FILTER BACK INTO THE REGION...WITH MONDAY/S HIGHS ABOUT 8-10F
COOLER AND TUESDAY SLIPPING ANOTHER COUPLE OF DEGREES AS TROUGH
LIFTS AWAY TO THE NE.

LOOKS LIKE LOWS IN THE MID/UPPER 30S AGAIN BECOME LIKELY ACROSS
THE NORTHERN MTNS FOR MIDWEEK AS LARGE AREA OF HIGH PRESSURE
SETTLES IN OVER NEW ENGLAND. TEMPS WILL GRADUALLY WARM HEADING
INTO NEXT WEEKEND.

&&

.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
A COLD FRONT...LOCATED ALONG THE NY/PA BORDER AT 21Z...WILL PUSH
SOUTH THROUGH PENNSYLVANIA THIS EVENING. DUE TO A LACK OF DEEP
MOISTURE...THE FRONT WILL PRODUCE NO PRECIP AND EVEN THE SCT CU
OBSERVED AT 21Z SHOULD DISSIPATE TOWARD SUNSET. THE MAIN AVIATION
CONCERN LATER TONIGHT WILL BE THE POSSIBILITY OF LOW CIGS
DEVELOPING OVR THE ALLEGHENY PLATEAU...THE RESULT OF RELATIVELY
MOIST EASTERLY FLOW ASCENDING THE HIGHER TERRAIN OF CENTRAL PA. A
PATCH OF LOWER CIGS ARE NOTED ACROSS WESTERN NY STATE AT 21Z IN
WAKE OF COLD FRONT AND NEAR TERM MDL DATA SUGGESTS THESE CLOUDS
COULD SPREAD INTO KBFD LATE THIS EVENING...AND EVEN POSSIBLY KJST
LATE TONIGHT. ALTHOUGH SOME PATCHY FOG IS CERTAINLY POSSIBLE LATE
TONIGHT...PRES GRADIENT SUGGESTS A NERLY BREEZE WILL MAKE WIDESPREAD
VIS RESTRICTIONS UNLIKELY.

ANY EARLY LOW CIGS ACROSS THE W MTNS SHOULD MIX OUT SHORTLY AFTER
SUNRISE FRIDAY. ALL MODEL DATA THEN SUPPORTS A HIGH CONFIDENCE
FCST OF VFR CONDS FOR THE REST OF THE DAY...AS HIGH PRES RIDGE
COVERS THE AREA.

OUTLOOK...
SAT...AM LOW CIGS/FOG POSSIBLE.
SUN...SLIGHT CHC OF PM TSRA IMPACTS W MTNS.
MON-TUE...NO SIG WX EXPECTED.

&&

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

&&

$$
SYNOPSIS...GARTNER
NEAR TERM...DEVOIR/GARTNER
SHORT TERM...LAMBERT/GARTNER
LONG TERM...RXR
AVIATION...FITZGERALD/GARTNER


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