-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KCTP 190553
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
153 AM EDT SUN MAY 19 2013

.SYNOPSIS...
A WAVY FRONTAL BOUNDARY EXTENDING FROM THE UPPER MIDWEST THROUGH
THE OHIO VALLEY AND ACROSS THE CENTRAL APPALACHIANS INTO SOUTHERN
MID-ATLANTIC STATES WILL SLOWLY RETURN NORTHWARD AS A WARM FRONT
LATE SUNDAY INTO MONDAY. THE WARM FRONT WILL THEN STALL OUT ACROSS
UPSTATE NEW YORK AND NEW ENGLAND BEFORE SINKING BACK TO THE SOUTH
AND OSCILLATING OVER PENNSYLVANIA INTO THE MIDDLE OF NEXT WEEK.
THE FRONT SHOULD FINALLY PUSH SOUTH OF THE AREA BY LATE NEXT WEEK
OR EARLY IN THE WEEKEND...AS A LARGE CANADIAN HIGH PRESSURE SYSTEM
DROPS SOUTHEAST INTO THE GREAT LAKES REGION. OVERALL EXPECT A
PROLONGED STRETCH OF UNSETTLED WEATHER OVER THE NEXT SEVERAL DAYS.
TEMPERATURES WILL BE MORE TYPICAL OF EARLY SUMMER BY TUESDAY...
BEFORE COOLING BELOW NORMAL BY NEXT WEEKEND.

&&

.NEAR TERM /UNTIL 9 AM THIS MORNING/...
-- Changed Discussion --
CLOUDS EXPANDING AS IF ON CUE...AND TEMPS SHOULD NOT MOVE MUCH FOR
THE REST OF THE NIGHT/EARLY MORNING. ALL IS ON TRACK AT 145 AM AND
NO CHANGES PLANNED OUTSIDE THE MINOR TEMP TWEAKS. PREV DISC...

A WEDGE OF RELATIVE COOL AND DRIER LLVL AIR /ALONG WITH WEAKLY
ANTICYCLONIC SE-SERLY MEAN FLOW IN THE SFC-1KM LAYER/ REMAINS
SITUATED BENEATH AN EXTENSIVE DECK OF STRATO CU DECK ACROSS MUCH OF
CENTRAL AND NRN PENN LATE THIS EVENING. CLOUD BASES HAVE BEEN
GRADUALLY LOWERING DURING THE EVENING...AND EXPECT THIS TREND TO
CONTINUE OVERNIGHT.

AREAS OF 1-3SM FOG WILL AFFECT PORTIONS OF THE LOWER SUSQ VALLEY
/AND LAUREL HIGHLANDS/ WHERE THE BEST LLVL DEWPOINTS AND/OR
STRONGEST SERLY UPSLOPE COMPONENT WILL BE LOCATED. CLOUD BASES WILL
LIKELY INTERSECT THE RIDGE TOPS /AOA 2000 FT MSL/ ACROSS THE CENTRAL
RIDGE AND VALLEY REGION AFTER 05Z SUNDAY.

RIGHT ENTRANCE REGION OF AN UPPER LEVEL JET MAX SLIDING SE OF THE
SRN NEW ENGLAND COAST WILL TAKE THE SCATTERED SHOWERS /CURRENTLY
AFFECTING OUR FAR ERN ZONES/ WITH IT FOR THE NEXT SEVERAL HOURS.

MEAN...925-850MB THETA-E WILL STEADILY INCREASE FROM S-N ACROSS THE
FCST AREA OVERNIGHT...AND COMBINE WITH ANOTHER FAST MOVING
UPPER LEVEL DISTURBANCE /SLIDING SE FROM THE GLAKES/ TO GRADUALLY
INCREASE THE CHANCE FOR SOME LIGHT SHOWERS OR DRIZZLE AFTER MIDNIGHT
TONIGHT. HIGHEST PROBABILITY /50-60 POPS/ FOR THE LIGHT QPF WILL BE
ACROSS THE SERN HALF OF THE CWA...AND MAINLY DURING THE PRE-DAWN
HOURS.

THE WIDESPREAD...THICK STRATUS/STRATO CU AND INCREASING LATE NIGHT
MOISTURE WILL HOLD MIN TEMPS IN THE 50S /ANYWHERE FROM 4-10 F ABOVE
NORMAL/.
-- End Changed Discussion --

&&

.SHORT TERM /9 AM THIS MORNING THROUGH 6 PM MONDAY/...
SHORT RANGE OPERATIONAL MODELS AND ENSEMBLE GUIDANCE POINTS TWD
CONTINUED WIDESPREAD AND GENERALLY 4-7 KFT THICK STRATO CU COVERING
MOST OR ALL OF THE CWA SUNDAY THROUGH SUNDAY NIGHT.

SERLY NEAR SFC FLOW...TOPPED BY INCREASINGLY MILD AND MOIST AIR
ALOFT WILL HELP TO CREATE AREAS OF VERY LIGHT RAIN OR DRIZZLE SUNDAY
AND SUNDAY NIGHT WITH A LOW PROBABILITY OF ANYTHING MORE THAN 0.10
OF AN INCH FOR THE 24 HOUR PERIOD.

TRIMMED DAYTIME TEMPS SUNDAY BY A FEW TO SVRL DEG F...MAINLY ACROSS
THE CENTRAL AND ERN ZONES...WHERE THE MORE PERSISTENT/THICKER CLOUD
COVER IS EXPECTED /ALONG WITH SOME INTERMITTENT LIGHT RAIN AND
DRIZZLE/.

MAX TEMPS WILL LIKELY ONLY REACH THE MID TO UPPER 60S /AT BEST/
ACROSS THE CENTRAL ZONES AND SUSQ VALLEY...AND 70-72F OVER THE WRN
MTNS. HIGHEST VALUES SUNDAY SHOULD BE NEAR AND TO THE WEST OF ROUTE
219.

&&

.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
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 SUPPORT ALOFT FOR ORGANIZED PRECIP WILL BE CONFINED 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 STARTING TOMORROW
NIGHT..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. WHERE THE FRONT WILL BE
ON ANY GIVEN DAY WILL HAVE MUCH TO DO WITH MESOSCALE INFLUENCES
FROM ANY CONVECTION THAT MANAGES TO FORM. AT THIS RANGE ALL THAT
CAN BE SAID IS THE BOUNDARY WILL BE HANGING AROUND NEARBY.

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
SOME COOLER AND DRIER CONDITIONS.

&&

.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
A WAVY FRONTAL BOUNDARY WILL REMAIN TO OUR SOUTH THROUGH THE TAF
PERIOD...BEFORE SLOWLY RETURNING NORTHWARD AS A WARM FRONT LATE
SUNDAY INTO MONDAY.

SCT SHOWERS AFFECTING SE ZONES WILL DIMINISH THIS EVE AS RIGHT
ENTRANCE REGION OF AN UPPER LEVEL JET MAX SLIDING SE OF THE SRN
NEW ENGLAND COAST. BUT INCREASINGLY MOIST SOUTHERLY FLOW WILL
BRING WIDESPREAD MVFR AND THEN IFR CONDITIONS TO ESPECIALLY
SOUTHERN HALF OF CWA...AND LOWERING OF CIGS ALREADY UNDERWAY AS
THEY CONTINUE TO TRANSITION TO IFR THROUGH 03-08Z. MEAN...925-850MB
THETA-E STEADILY INCREASES FROM SOUTH TO NORTH LATER TONIGHT...AND
COMBINE WITH ANOTHER FAST MOVING UPPER LEVEL DISTURBANCE /SLIDING
SE FROM THE GLAKES/ WILL GRADUALLY INCREASE THE CHANCE FOR SOME
LIGHT SHOWERS OR DRIZZLE AFTER MIDNIGHT TONIGHT. HIGHEST
PROBABILITY FOR THE LIGHT QPF WILL BE ACROSS THE SOUTHERN HALF OF
THE STATE BETWEEN 06-12Z.

LOW CIGS WILL PERSIST INTO SUNDAY...WITH SOME IMPROVEMENT TO MVFR
LIKELY SUNDAY AFTERNOON...BEFORE WIDESPREAD IFR RETURNS FOR SUNDAY
EVE INTO MONDAY AS A 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.

&&

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

&&

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