Area Forecast Discussion
Issued by NWS State College, PA

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000
FXUS61 KCTP 162048
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
448 PM EDT TUE SEP 16 2014

.SYNOPSIS...
HIGH PRESSURE WILL BUILD IN FROM THE MIDWEST 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 6 AM WEDNESDAY MORNING/...
INVERSION LOWERING AND DEWPOINTS OVER THE NORTHWEST ARE DROPPING
NEAR 40F AT 18Z. CLOUDS SHOULD DISSIPATE RATHER RAPIDLY AND MOST
WILL BE GONE BY SUNSET. SOME MOISTURE MAY BUBBLE OFF THE LAKE AND
KEEP SCT CLOUDS IN THE NORTHWEST. BUT LOWERING DEWPOINTS...GOOD
RADIATIONAL COOLING...AND CALM AIR WILL ALLOW FOR TEMPS TO DROP
OFF. AFTER COLLABORATION DISCUSSIONS WITH SURROUNDING
OFFICES...THE CONSENSUS IS THAT WE WILL ONLY MENTION PATCHY FROST
IN THE NORTHERN MOUNTAINS TONIGHT/WED AM DUE TO UNCERTAINTY WITH
THE AMOUNT OF CLOUDS. DEWPOINTS MAY ALSO BE TOUGH TO PUSH DOWN AND
RIVER VALLEY FOG WILL ALSO FORM. ALL THESE SHOULD WORK AGAINST A
WIDESPREAD FROST. WILL MENTION VALLEY FOG ALMOST EVERYWHERE AND
ALSO KEEP JUST A LITTLE HINT OF LOWER CLOUDS IN THE GRIDS FOR
THOSE VALLEY LOCATIONS.

&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/...
HIGH PRESSURE PRETTY MUCH OVERHEAD ON WED. DIURNAL CU ARE EXPECTED
AFTER THE MORNING VALLEY FOG LIFTS AND COOL AIR ALOFT LEADS TO
SOME LIMITED INSTABILITY. ON THE WHOLE...A REALLY NICE DAY. TEMPS
SHOULD GET BACK INTO THE LOWER 60S ON THE HIGHEST OF ELEVATIONS OF
THE NW AND MID 70S IN THE LOWEST/URBAN LOCATIONS IN THE SE.

&&

.LONG TERM /WEDNESDAY 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 /21Z TUESDAY THROUGH SUNDAY/...
SCT-BKN CU WITH BASES BTWN 5-7KFT SHOULD DISSIPATE QUICKLY THIS
EVENING AS THE SUN SETS. HIGH PRESSURE CENTERED OVER THE MIDWEST
WILL DRIFT INTO THE REGION TONIGHT...SETTING THE STAGE FOR LATE
NIGHT VALLEY FOG IN THE 08-14Z TIME FRAME. EXPECT A PERIOD OF
IFR/LIFR VSBYS AT MOST CENTRAL PA AIRFIELDS. POSSIBLE EXCEPTIONS
MAY BE KJST AND KMDT...WHERE CLIMATOLOGY INDICATES RADIATION FOG
IS LESS LIKELY.

AFTER THE FOG BURNS AWAY ON WED...THERE WILL BE SOME DIURNAL CU.
DEWPOINTS ARE SO LOW THAT THEY WILL BE HIGH-BASED. SIMILAR
CONDITIONS ARE EXPECTED UNTIL THE WEEKEND AS HIGH PRESSURE REMAINS
IN CONTROL.

OUTLOOK...
WED-SAT...AM FOG...OTHERWISE NO SIG WX.
SUN...SCT SHRA POSS - MAINLY DRY CFROPA.

&&

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

&&

$$
SYNOPSIS...DANGELO
NEAR TERM...DANGELO
SHORT TERM...DANGELO
LONG TERM...RXR
AVIATION...DANGELO/FITZGERALD


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