Area Forecast Discussion
Issued by NWS State College, PA

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FXUS61 KCTP 180610
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
210 AM EDT THU SEP 18 2014

.SYNOPSIS...
A TROUGH OF LOW PRESSURE OVER EASTERN NORTH AMERICA WILL SLOWLY
WEAKEN INTO SATURDAY BEFORE RE-INTENSIFYING LATER ON SUNDAY ONCE
AGAIN. OVERALL IT SHOULD BE A RELATIVELY COOL AND DRY PERIOD WITH
A BRIEF WARM UP OVER THE WEEKEND.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
MUCH OF THE DIURNAL CUMULUS HAS DISSIPATED...BUT BUT STILL SEEING
SCATTERED STRATOCU FROM THE LAUREL HIGHLANDS THROUGH THE CENTRAL
MOUNTAINS LATE THIS EVENING. THIS MAINTENANCE IS BEING
ACCOMPLISHED BY A WEAK SHORTWAVE OVER THE LAUREL HIGHLANDS THIS
EVENING WHICH WILL TRACK ACROSS THE SOUTHERN TIER AND OFF THE
SOUTH NJ COAST BY 12Z THU.

HIGH CLOUDS ASSOCIATED WITH A MORE IMPORTANT UPPER TROF DROPPING
THROUGH THE CENTRAL GLAKS WILL APPROACH THE NORTHWEST MOUNTAINS
TOWARDS DAWN. PATCHY VALLEY FOG WILL BE THE ONLY SENSIBLE WEATHER
OVERNIGHT. MIN TEMPS WILL STILL BE ON THE COOL SIDE...RANGING
FROM THE LOWER TO MIDDLE 40S OVER THE NORTHERN TWO THIRDS OF
CENTRAL PA...TO THE LOWER 50S ACROSS THE SOUTH.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH FRIDAY NIGHT/...
ANOTHER DRY AND SEASONABLY COOL DAY. A WEAK FRONTAL BOUNDARY WILL
MOVE ACROSS THE REGION BRINGING SLIGHTLY COOLER AIR AND JUST
SCATTERED CLOUD COVER. THURSDAY NIGHT WILL BY QUITE COLD WITH
FROST POSSIBLE ACROSS THE COLDEST VALLEYS...AND A FROST ADVISORY
MAY HAVE TO BE ISSUED FOR PORTIONS OF WESTERN PA FOR FRIDAY
MORNING ON THURSDAY.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
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...TROUGH BEGINS TO
CARVE INTO ZONAL FLOW OVER THE GREAT LAKES AS A SYSTEM APPROACHES
PA FOR SUN/MON. THE 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 WELL INTO THE 40S AND 50S. 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 IS THE
WETTEST WITH QPF POTENTIALLY UP TO 0.25...WHILE THE GFS BRINGS
LIGHTER AMOUNTS.

THE 500 HPA TROUGH BEHIND THE FRONT DEEPENS OVER THE REGION MONDAY
INTO TUESDAY. THIS WILL KEEP MENTION FOR SCT INSTABILITY SHOWERS
MONDAY INTO TUESDAY...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 FALLING ANOTHER 5F
OR SO. OVERNIGHT LOWS WILL SLIP BACK INTO THE 40S MON NIGHT...WITH
SOME MID/UPPER 30S POSS IN THE NORTHERN MTNS TUE NIGHT.

TROUGH LIFTS TO THE NE BY MIDWEEK AS HIGH PRESSURE SETTLES BACK
IN. AS FLOW AGAIN TURNS AROUND TO THE SW...REGION SHOULD SEE
ANOTHER GRADUAL WARMUP FOR LATE WEEK.

&&

.AVIATION /06Z THURSDAY THROUGH MONDAY/...
IR SATELLITE SHOWS BROKEN LAYER OF SC OVER CENTRAL AND SOUTHWEST
PENNSYLVANIA TONIGHT. IF THESE CLOUDS PERSIST...IT WILL LIMIT FOG
FORMATION OVERNIGHT. HOWEVER...AS PREVIOUS DISCUSSION
NOTED...CONFIDENCE NOT THAT HIGH TO TOTALLY RULE OUT A PERIOD OF
MVFR TO IFR VSBYS BY EARLY MORNING. HAVE CONTINUED TREND OF
INCLUDING MVFR FOG CONDITIONS FOR SEVERAL HOURS AT ALL TAF
LOCATIONS...EXCEPTION IS AT KIPT...WHERE HAVE FOLLOWED GUIDANCE
SUGGESTING THE TYPICAL LOW STRATUS AT JUST A FEW HUNDRED FEET
EARLY IN THE MORNING.

ANY FOG THAT DOES FORM SHOULD BURN OFF BTWN 13Z-14Z. A MOISTURE-
STARVED COLD FRONT WILL BE PUSHING SOUTHEAST THRU THE REGION THIS
AFTERNOON. EXPECT VFR CONDITIONS ACROSS ALL OF CENTRAL
PENNSYLVANIA TODAY INTO TONIGHT...THEN AGAIN WILL SEE SOME FOG
FORMATION THURSDAY NIGHT.


OUTLOOK... FRI...PATCHY AM FOG POSSIBLE...MAINLY NORTH.
SAT...AM LOW CIGS/FOG POSSIBLE.
SUN...SLIGHT CHC OF PM TSRA IMPACTS W MTNS.
MON...NO SIG WX EXPECTED.

&&

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

&&

$$
SYNOPSIS...ROSS
NEAR TERM...ROSS/DEVOIR
SHORT TERM...ROSS
LONG TERM...RXR
AVIATION...JUNG/FITZGERALD


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