000
FXUS61 KCTP 190003
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
803 PM EDT SAT MAY 18 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 6 AM SUNDAY MORNING/...
A WEDGE OF RELATIVE COOL AND DRIER LLVL AIR /ALONG WITH WEAKLY 
ANTICYCLONIC SE-SERLY MEAN FLOW IN THE SFC-1KM LAYER/ IS SITUATED 
BENEATH AN EXTENSIVE AND FAIRLY HIGH-BASED STRATO CU DECK ACROSS 
MUCH OF CENTRAL AND NRN PENN EARLY THIS EVENING. THE EASTERN EDGE OF 
HIGHER LLVL DEWPOINTS AND AXIS OF MIXED-LAYER INSTABILITY EXTENDED 
ACROSS THE LAUREL HIGHLANDS WHERE MU CAPE VALUES WERE IN THE 500-900 
J/KG RANGE WITH A FEW ISOLATED SHOWERS PRESENT. 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 LATER TONIGHT...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 SOUTHERN HALF OF THE STATE 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/.

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/...
ALL SHORT RANGE MODEL GUIDANCE MAKES POINTS TWD CONTINUED WIDESPREAD 
AND GENERALLY 4-7 KFT THICK STRATO CU COVERING MOST OR ALL OF THE 
CWA 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. 

WILL WAIT TO EXAMINE THE 21Z SREF AND SOME LATER HIGH RES MODEL DATA 
BEFORE POSSIBLY TRIMMING 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 HOLD IN THE MID TO UPPER 60S 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 /SUNDAY 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 /00Z 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...LAMBERT/MARTIN
SHORT TERM...DANGELO/MARTIN
LONG TERM...LA CORTE/STEINBUGL
AVIATION...RXR