Area Forecast Discussion
Issued by NWS State College, PA

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FXUS61 KCTP 170551
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
151 AM EDT WED SEP 17 2014

.SYNOPSIS...
A STRONG TROUGH OVER EASTERN NORTH AMERICA WILL SLOWLY WEAKEN
FRIDAY INTO SATURDAY BEFORE RE-INTENSIFYING SUNDAY INTO MONDAY.
OVERALL IT SHOULD BE A RELATIVELY COOL DRY PERIOD WITH A BRIEF
WARM UP OVER THE WEEKEND.

&&

.NEAR TERM /UNTIL 8 AM THIS MORNING/...
HIGH PRESSURE TO OUR WEST IS SLOWLY MOVING EAST. SOME PATCHES OF
LOW CLOUDS CONTINUE TO DRIFT ACROSS PORTIONS OF WEST/CENTRAL PENNSYLVANIA.

DEW POINTS RANGE FROM THE MID 30S TO THE AROUND 50. OVERNIGHT LOWS
SHOULD RANGE THE LOW-MID 30S INTO NEAR 50 IN THE SOUTHEAST.

PATCHY FROST POSSIBLE IN THE NORTHWEST.

&&

.SHORT TERM /8 AM THIS MORNING THROUGH 6 PM THURSDAY/...
HIGH PRESSURE WILL CONTINUE TO BUILD IN FROM THE WEST OVER THIS
PERIOD. MOSTLY CLEAR WEDNESDAY WITH HIGHS MAINLY IN THE 60S.

ANOTHER COOL DRY AIR MASS AND STRONGER SURFACE HIGH PUSH INTO THE
REGION THURSDAY. THURSDAY COULD BE BIT WARMER...SOME AREAS WILL
REACH INTO THE LOW 70S. BUT THE LARGE ANTICYCLONE AND DRY AIR
COULD PROVIDE A VERY COLD OVERNIGHT THURSDAY INTO FRIDAY.

OVERALL WED-THURSDAY SHOULD BE COOLER THAN NORMAL AND DRY.

&&

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
UPPER TROUGH SHARPENS OVER QUEBEC WED NIGHT/THU AS A SHORTWAVE
SLIDES THROUGH...PUSHING A WEAK FRONTAL BOUNDARY SOUTH TOWARD PA
ON THU. THIS FRONT WILL CONTINUE TO WEAKEN AS IT EDGES
SOUTHWARD...BUT ANOTHER SHORTWAVE WILL SLIDE OVERHEAD FROM THE
MIDWEST ON THU. THIS WILL BRING AN INCREASE IN MID LEVEL
INSTABILITY AND THUS A MORE ROBUST CLOUD FIELD 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.

BROAD RIDGE OVER CENTRAL U.S. FLATTENS AS IT WORKS EAST...WITH A
STRENGTHENING BUBBLE OF SURFACE HIGH PRESSURE BUILDING 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 WILL LIKELY SPREAD ACROSS MUCH OF CWA
NORTH OF I-80 THU NIGHT/EARLY FRIDAY AND INTO TYPICALLY COLD RURAL
LOCATIONS OF SCENT PENN...AND WILL HAVE TO KEEP AN EYE ON FOR
POTENTIAL FROST/FREEZE IMPACTS. THE HIGH TEMPS FRI WILL BE MAINLY
IN THE 60S AS NW FLOW CONTINUES.

RETURN FLOW BEGINS FRI NIGHT...TAKING A LITTLE OF THE BITE OUT OF
OVERNIGHT LOWS IN THE WEST WITH READINGS 5-8F WARMER. DRIER AIR
AND DECOUPLED LOW LEVELS WILL KEEP THE EAST COOLER...BUT STILL NOT
QUITE AS CHILLY AS THU NIGHT. THE RETURN FLOW WILL BEGIN A
WARMING TREND FOR THE WEEKEND. TEMPS SAT WILL BE 5-8F WARMER THAN
FRI...AND SUNDAY WILL BE EVEN A FEW DEGREES WARMER 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...MODELS STILL AGREE UPON A DEEPENING LOW
CENTERED WELL TO OUR NORTH AS A TROUGH AXIS ROTATES THROUGH THE
GREAT LAKES. THIS WILL BRING PLENTY OF CLOUDS AND A CHANCE FOR
SHOWERS...AND EVEN THOUGH GFS/ECMWF SETTLING IN ON
TIMING...STRENGTH OF SYSTEM STILL BEING DEBATED WITH GFS BRINGING
A MORE ROBUST SHOT OF PRECIP FOR LATER SUN/SUN NIGHT.

TROUGH SETTLES IN OVER PA FOR EARLY NEXT WEEK...WITH NW/N LOW
LEVEL FLOW BRINGING COOLER AND DRIER AIR INTO THE REGION. THERE
WILL LIKELY BE ENOUGH MID LEVEL INSTABILITY ON MONDAY TO LIMIT SUN
ACROSS NORTHERN AND CENTRAL MTNS...AND EVEN POTENTIALLY KICK OFF A
FEW LIGHT SHOWERS. TUE LOOKS CHILLIER AND DRY.

&&

.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
HIGH PRESSURE CENTERED OVER THE MIDWEST WILL DRIFT INTO THE REGION
TONIGHT. THE MCLEAR SKY AND NEARLY CALM WIND WILL PROMOTE LATE
NIGHT VALLEY FOG IN THE 07Z-13Z TIME FRAME. EXPECT AT LEAST A
BRIEF PERIOD OF IFR/LIFR VSBYS AT MOST CENTRAL PA AIRFIELDS.
LIKELY EXCEPTIONS WILL BE KJST AND KMDT...WHERE CLIMATOLOGY INDICATES
RADIATION FOG IS LESS LIKELY.

ANY FOG SHOULD BURN OFF BTWN 13Z-14Z. HIGH PRES AND ASSOC DRY AIR
MASS OVER THE REGION WILL TRANSLATE TO A NEAR CERTAINTY OF VFR
CONDS AND LIGHT WINDS FOR THE REST OF THE DAY.

OUTLOOK...
THU-FRI...PATCHY AM FOG POSSIBLE...MAINLY NORTH.
SAT-SUN...NO SIG WX EXPECTED.

&&

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

&&

$$
SYNOPSIS...GRUMM
NEAR TERM...GRUMM
SHORT TERM...GRUMM
LONG TERM...RXR
AVIATION...FITZGERALD/CERU



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