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000
FXUS61 KCTP 171129
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
729 AM EDT FRI MAY 17 2013

.SYNOPSIS...
A FRONTAL BOUNDARY WILL REMAIN ALONG THE MASON DIXON LINE THIS
MORNING. HIGH PRESSURE WILL MIGRATE EASTWARD ACROSS SOUTHEASTERN
CANADA WITH ONSHORE FLOW DEVELOPING ACROSS THE MID-ATLANTIC
REGION. THE FRONTAL BOUNDARY WILL SLOWLY PUSH BACK TO THE NORTH AS
A WARM FRONT OVER THE WEEKEND...AND LIFT NORTH OF THE AREA BY
EARLY NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
STRATUS IS BREAKING UP A BIT AS IT SLIDES INTO THE LAURELS.
HOWEVER...OBS AT JST INDICATE CLOUDS/FOG HAVE ROLLED IN AND WILL
CARRY CLOUDS AND AREAS OF FOG EARLY THIS MORNING. DAYLIGHT AND THE
INVIGORATION OF THE NRLY FLOW SHOULD HELP TO DRY THEM UP...BUT
THE MOISTURE WILL LIKELY REAPPEAR AS THE TEMPS OVER THE SWRN COS
SHOULD GET WARM ENOUGH /70F PLUS/ TO POP DIURNAL CUMULUS. DRY AIR
FROM THE SFC HIGH TO THE N WILL TRY TO PUSH THE MOISTURE TO THE
SOUTH OF THE BORDER...BUT THE WNW FLOW ALOFT THIS MORNING/EARLY
AFTN WILL HAMPER THAT EFFORT. THE CU COULD GROW TALL ENOUGH TO POP
A SHOWER/TSTM THIS AFTN...AND WILL CARRY SLIGHT/LOW CHC POPS IN
THE LAUREL MOUNTAINS. MAXES SHOULD BE IN THE 70S OVER ALL BUT THE
NRN MTS AND POCONOS. SFC WINDS WILL BE VERY LIGHT. ANY SHOWERS
COULD BE CARRIED TO THE EAST EARLY THIS EVENING. BY AND
LARGE...THE GREAT MAJORITY OF THE FORECAST AREA WILL BE DRY WITH
LOW DEWPOINTS AND ONLY HIGH CLOUDS OVERHEAD.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
JUST A SLIGHT CHC OF A SHOWER WILL LAST INTO THE NIGHT OVER SRN
BORDER. THE DEGREE OF INFLUENCE THE FILLING UPPER LOW COMING OUT
OF THE PLAINS WILL HAVE IS A TOUGH CALL. HOWEVER...GENERAL MDL
PREFERENCE IS TO KEEP THE BULK OF THE SHRA S OF THE STATE. CERTAINLY
THE HIGH CLOUDS WILL THICKEN UP AND COULD HELP KEEP TEMPS MILDER
TONIGHT THAN THIS MORNING...WITH MINS IN THE N IN THE M/U40S AND
M50S S. EXPECT LITTLE/NO WIND TONIGHT OVER MOST OF THE
AREA...EXCEPT FOR THE WRN MTS FARTHER FROM THE AXIS OF THE
WEAKENING SFC RIDGE. THE GENERAL FLOW PATTERN DOES BECOME MORE
E/SERLY LATER TONIGHT AND CERTAINLY DURING THE DAY ON SAT. THE
MID/HIGH CLOUDS COULD KEEP MAXES DOWN IN THE L70S FOR MOST AREAS.
HOWEVER...HEATING SHOULD BE SUFFICIENT TO POP A FEW CU AGAIN ON
SAT...ESP OVER THE HIGHER ELEVATIONS. THE MOISTURE FROM THE
ATLANTIC OCEAN WILL START TO BE DRAWN NORTHWARD ALONG THE
APPALACHIANS AND WILL START TO BUILD UP LATER SAT NIGHT. THIS
SHOULD KEEP MINS MILD. WILL ALSO KEEP THE LOW CHC FOR SOME LIGHT
RAIN AS THE MARITIME MSTR CLIMBS UPHILL SAT NIGHT...WITH HIGHER
30-40 POPS S AND SLIGHT CHC N.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
NO BIG CHANGES NECESSARY TO LONGER RANGE FORECAST BASED ON LATEST
COMPUTER GUIDANCE.

NEARLY STATIONARY FRONTAL BOUNDARY WILL REMAIN SOUTH OF PA THROUGH
SUNDAY. LIGHT UPSLOPE FLOW CONTINUES AND SHOULD MAKE SUN AS COOL
OR COOLER THAN SAT.

WARM FRONT APPEARS TO PUSH THROUGH ON MONDAY...WITH MENTION OF
SCT SHOWERS/TSTMS. PWATS INCREASE MORE NOTICEABLY HEADING INTO
TUE-WED AS LARGE SCALE PATTERN AMPLIFIES...AND HEIGHTS BUILD OVER
PA. MAIN SYNOPTIC FEATURE OF INTEREST WILL BE AN UPPER LOW OVER
THE NRN PLAINS/UPR MS VLY. H5 HGTS SHOULD RISE DOWNSTREAM OF THIS
SYSTEM...WITH CENTRAL PA SOLIDLY IN THE WARM SECTOR BY TUE. THIS
SHOULD AFFORD ONE OR TWO VERY WARM LATE SPRING DAYS WITH HIGHS
75-80F AND LOW CHANCES FOR DAILY TSTMS. THERE IS NOTICEABLE SPREAD
BETWEEN THE GFS/ECMWF CONCERNING THE POTENTIAL EVOLUTION OF THE
UPPER MIDWEST CUT-OFF...BUT SETTLED ON BRINGING THE COLD FRONT
THROUGH ON WED-WED NIGHT /ALONG WITH HIGHEST POPS/. STRONG SURFACE
HIGH BUILDS ACROSS GLAKES UNDER UPPER TROUGH LATE WEEK...BRINGING
COOLER AND DRIER CONDITIONS TO CENTRAL PA.

&&

.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
17/12Z...

2-4SM VIS AND SCT-BKN 1-1.5KFT CIGS AT JST WILL IMPROVE TO VFR
WITHIN THE NEXT FEW HOURS. ELSEWHERE...EXPECT A CONTINUATION OF
VFR CONDS WITH PATCHES OF SCT-BKN CIRRUS.

MVFR CIGS COULD DEVELOP AS EARLY AS LATE TONIGHT INVOF JST/AOO AS
LLVL FLOW SHIFTS TO THE ESE. CONFIDENCE IN MVFR CIGS IS LOW
TONIGHT. HOWEVER THE DEVELOPING ONSHORE/SELY FLOW WILL EVENTUALLY
INTERSECT A RETURNING WARM FRONT AND RESULT IN HIGHER CONFIDENCE
FOR CIG/VIS RESTRICTIONS AND PSBL LGT RAIN/DRIZZLE/FOG LATER SAT
INTO MONDAY. WARM FRONT WILL LIFT NORTH OF PA ON TUESDAY WITH
SUMMERTIME WARM/MOIST CONDITIONS LKLY FUELING DIURNAL ISOLD-SCT
SHWRS/TSTMS.

.OUTLOOK...

SAT...CIGS LOWERING WITH MVFR/IFR LKLY BY SAT NGT.
SUN-MON...MVFR/IFR CIGS WITH OCNL -RA/-DZ.
TUE...VFR/MVFR WITH SCT SHOWERS/TSTMS.

&&

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

&&

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