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000
FXUS61 KCTP 191643
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
1223 PM EDT SUN MAY 19 2013

.SYNOPSIS...
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HIGH PRESSURE OVER THE NORTHEASTERN STATES WILL SLIDE OFF THE COAST
THIS AFTERNOON. A PROLONGED STRETCH OF UNSETTLED WEATHER IS IN
STORE OVER THE NEXT SEVERAL DAYS AS A STORM SYSTEM CURRENTLY OVER
THE CENTRAL PLAINS INCHES EASTWARD. TEMPERATURES TODAY WILL
GRADUALLY RISE THROUGH THE FIRST PART OF THE WEEK...BUT WILL COOL
BACK BELOW NORMAL BY NEXT WEEKEND.
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&&

.NEAR TERM /UNTIL 8 PM THIS EVENING/...
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A MOIST SOUTHEASTERLY FLOW NEAR THE SFC AND PLUME OF ANOMALOUSLY
HIGH PWAT AIR /1.5-1.75 INCHES/ MOVING INTO THE REGION FROM THE
SOUTH WILL CONTINUE TO LOCK IN THICK CLOUD COVER ACROSS PRACTICALLY
ALL OF THE CWA FOR THE REST OF TODAY.

PORTIONS OF THE NW MTNS WILL CONTINUE TO SEE PERIODS OF SUNSHINE
THROUGH THIS AFTERNOON...SINCE THE DEPTH OF THE MOISTURE IS THE MOST
SHALLOW THERE...AND LLVL DOWNSLOPING TO THE WEST OF THE SPINE OF THE
APPALACHIANS WILL OCCUR.

THE BASE OF THE THICK STRATUS/STRATOCU DECK WILL BE DRAPED OVER THE
HIGHER RIDGE TOPS. HOWEVER...THE STRONG...LATE MAY SUN WILL WARM
THE BLYR A FEW...TO SVRL DEG F MORE AND LIFT THE BASE OF THE DECK UP
ANOTHER 200-500 FT FROM THEIR 16Z LEVELS.

WEAK FORCING IN THE FORM OF VERY GENTLE ISENTROPIC UPGLIDE FROM THE
SOUTH TO SSW WITHIN THE I300-310K THETA CHANNEL WILL HELP TO PRODUCE
A FEW LIGHT SHOWERS /OR MORE LIKELY AREAS OF DRIZZLE/ THAT WILL
DRIFT NNE ACROSS THE FCST AREA THIS AFTERNOON INTO THIS EVENING.

THE CLOUDS WILL KEEP TEMPS ON THE COOL SIDE AND WELL BELOW NORMALS
ACROSS MOST OF THE AREA. JUST THOSE LUCKY FEW PLACES OVER THE
NORTHWEST MTNS COULD MEET OR EXCEED CLIMO HIGHS. MAX TEMPS WILL BE
MAINLY IN THE MID 60S...BUT SHOULD HOLD AOB 60F ACROSS SOME OF THE
EASTERN MTNS.
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&&

.SHORT TERM /8 PM THIS EVENING THROUGH TUESDAY/...
A MINOR UPPER RIDGE IS GENERALLY IN PLACE FROM THE UPPER GREAT
LAKES TO THE GULF COAST. HOWEVER...THE OLD MID-LEVEL LOW IS STILL
SEEN IN MDL INITIALIZATIONS OVER THE OHIO VALLEY. THIS FEATURE AND
THE DEAD/DIFFUSE FRONT TO OUR SOUTH WILL CONTINUE TO GENERATE
SHOWERS ALL ACROSS THE MID-ATLANTIC FOR THE NEXT TWO DAYS UNTIL
THE LOW FINALLY DISAPPEARS SOMETIME AROUND MONDAY NIGHT AS IT
PASSES OVERHEAD. UPSTREAM CONVECTION WILL BE DROPPING ACROSS THE
GREAT LAKES AND WILL ONLY PROLONG THE CLOUDY/SHOWERY FORECAST FOR
LATE THIS PERIOD.

ON TUESDAY...WE SHOULD ENTER THE WARM SECTOR AHEAD OF THE STORM
LANGUISHING OVER THE PLAINS/MIDWEST/UPPER LAKES. THE WARM SECTOR
AIR WILL BE QUITE WARM FOR THE TIME OF YEAR...HAVING SPENT PLENTY
OF TIME COOKING OVER THE MS AND OH VALLEYS WITH GOOD GULF INFLOW.
TEMPS THERE RIGHT NOW ARE ABOUT 10F ABOVE AVERAGES. THEREFORE...THE
TEMPS SHOULD ROUND OUT TO 80F OR BETTER IN MANY LOCATIONS TUES.
BUT SCT AFTN CONVECTION IS THEN POSSIBLE.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
THE MEDIUM RANGE GUIDANCE CONTINUES TO ADVERTISE A RATHER
UNSETTLED PERIOD OF TIME FOR MUCH OF THE UPCOMING WEEK.

WE ARE AND WILL REMAIN BASICALLY UNDER A MEAN UPPER RIDGE...BUT
THE PROBLEM WILL BE A WEAK FRONTAL SYSTEM THAT WILL BE MEANDERING
AROUND CENTRAL PA FOR MUCH OF THE TIME INTO LATE WEEK. SO WHILE
THERE IS SUPPORT ALOFT FOR ORGANIZED PRECIP...THE SHOWERS WILL BE
TIED TO SMALL SCALE FEATURES THAT WILL BE HARD TO SEE MORE THAN A
DAY OR TWO DOWN THE ROAD. THE LOW LEVEL FORCING AND INCREASING
HUMIDITY/INSTABILITY WILL BRING SEVERAL CHANCES FOR MAINLY DIURNAL
SHOWERS AND THUNDERSTORMS.

THE FORECAST HAS A LOT OF REDUNDANCY IN IT...IMPLYING A PROLONGED
PERIOD OF RAIN/STORMS. THE REALITY IS LIKELY TO BE MORE LIKE A
PERIOD OF MAINLY CLOUDY SKIES BUT WITH SUNNY BREAKS DURING THE
DAY...ALONG WITH SHOWERS THAT WILL BE MOST LIKELY IN THE AFTERNOON
AND EVENING. A DIFFUSE FRONT WILL ATTEMPT TO PUSH NORTHWARD DURING
THE MIDDLE OF THE WEEK. WHERE THE FRONT WILL BE ON ANY GIVEN DAY
WILL HAVE MUCH TO DO WITH MESOSCALE INFLUENCES FROM ANY CONVECTION
THAT MANAGES TO FORM.

DESPITE AMPLE CLOUD COVER AND THE CHANCES FOR RAIN...TEMPERATURES
SHOULD REMAIN ABOVE NORMAL UNTIL AT LEAST LATE WEEK WHEN GUIDANCE
SUGGESTS WE FINALLY SEE A COLD FRONT MOVE THROUGH USHERING IN
MUCH COOLER AIR AND DRIER CONDITIONS.

&&

.AVIATION /16Z SUNDAY THROUGH THURSDAY/...
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A WAVY FRONTAL BOUNDARY JUST TO OUR SOUTH WILL SLOWLY RETURN
NORTHWARD ACROSS PENNSYLVANIA AS A WARM FRONT LATE TODAY INTO MONDAY.

WIDESPREAD IFR /TO LOW END MVFR CIGS/ WITH GENERALLY 7-10SM VSBYS
WILL CONTINUE THROUGH THE AFTERNOON HOURS. LOWEST CONDITIONS WILL BE
FOUND ACROSS THE SOUTHERN THIRD OF PENN.

RIDGE TOPS AOA APPROX 1900 FT MSL WILL CONTINUE TO BE SHROUDED IN
THE LOW CLOUDS/FOG THROUGH AT LEAST EARLY THIS AFTERNOON.

AREAS OF DRIZZLE AND SOME SHRA WILL BE MOVING BACK TOWARD PA FROM
THE SOUTH THIS AFTERNOON AS WELL. THE HIGHEST PROBABILITY FOR THE
LIGHT QPF WILL BE ACROSS THE SOUTHERN PA TAF AIRFIELDS
/KJST/LNS/MDT/CXY.

AFTER SOME MINOR...BRIEF IMPROVEMENT TO CIGS AND VSBYS THIS
AFTERNOON...WIDESPREAD IFR RETURNS FOR LATER THIS EVE INTO MONDAY AS
THE AFOREMENTIONED WARM FRONTAL BOUNDARY LIFTS SLOWLY NORTHWARD.

A RATHER UNSETTLED AND POTENTIALLY WET PATTERN IS EXPECTED DURING
THE MIDDLE TO SECOND HALF OF UPCOMING WEEK...WITH DAILY CHC/S FOR
CONVECTIVE PCPN AND ASSOCD RESTRICTIONS.

.OUTLOOK...
MON...MVFR-IFR CIGS.
TUE-THU...VFR-MVFR WITH SCT PM THUNDERSTORM IMPACTS.
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&&

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

&&

$$
SYNOPSIS...DANGELO/LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...DANGELO/LAMBERT
LONG TERM...LA CORTE/STEINBUGL
AVIATION...LAMBERT