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000
FXUS61 KCTP 201913
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
257 PM EDT MON MAY 20 2013

.SYNOPSIS...
A WARM FRONT WILL MOVE SLOWLY NORTHEAST ACROSS THE STATE THIS
AFTERNOON AND EVENING. INCREASING WARMTH AND HUMIDITY WILL
OVERSPREAD THE REGION THROUGH THE MID-WEEK IN THE WAKE OF THIS
FRONT. EXPECT WELL ABOVE NORMAL AFTERNOON TEMPERATURES ACROSS THE
WESTERN HALF OF THE STATE THIS AFTERNOON...AND IN ALL AREAS TUESDAY
AND WEDNESDAY. TEMPERATURES WILL COOL BACK BELOW NORMAL WITH DRIER
CONDITIONS BY THE WEEKEND AS A VERY COLD AIRMASS DROPS OUT OF
CENTRAL CANADA INTO THE GREAT LAKES AND NORTHEASTERN UNITED STATES.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
EARLIER LOW STRATUS HAS TRANSITIONED INTO WIDESPREAD SCT-BKN FAIRLY
SHALLOW CU/STRATO CU FIELD ACROSS THE CWA AT MID AFTERNOON.

A RIBBON OF CONVECTION /NO THUNDER YET/ WAS DEVELOPING ACROSS THE
LAUREL WHERE EARLIER CLEARING AND HI LEVEL HEATING HAS RAMPED UP
MIXED LAYER CAPES TO AROUND 1500 J/KG. WARMING ALOFT SHOULD KEEP ANY
TSRA RATHER LOW-TOPPED AND ISOLATED LATE TODAY.

TEMPS ACROSS THE CENTRAL AND WEST ARE RIGHT AROUND THEIR FCST HIGHS
IN THE UPPER 70S TO LOWER 80S FOR HIGHS...AND SLIGHTLY COOLER IN THE
MID 70S ACROSS THE EAST. A FEW SPOTS IN SCENT PENN /JUST EAST OF THE
LAURELS/ COULD TOUCH 85F WHERE THE  MEAN...DOWNSLOPING SWRLY LLVL
FLOW MAXIMIZING THE ADIABATIC WARMING OF THE 14C AIR RESIDING AT THE
850 MB LEVEL.

ALTHOUGH ALL MDL SOUNDINGS CONTINUE TO INDICATE THE ISOLD/SCT SHRA
THAT ARE SEEN FORMING OVER THE PAST HOUR OR SO...IN THE SRN TIER AND
ANOTHER AREA OVER THE NWRN MTS...BROADLY DIVERGENT LLVL FLOW WILL
ACT TO NEGATE ANY ORGANIZED AREAS OF DEEP CONVECTION THROUGH THE
REST OF THE DAYLIGHT HOURS.

WILL INCREASE POPS TO HIGH CHC/ LOW LIKELY ACROSS THE SW MTNS ...BUT
CONTINUE TO KEEP POPS OVER THE NE HALF OF THE CWA BELOW 20 PERCENT.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/...
MORE LOW STRATUS AND FOG ARE LIKELY LATE TONIGHT SINCE WILL
DEWPOINTS REMAIN HIGH AND WINDS WILL FALL OFF TO LIGHT AND VARIABLE.
WILL COUNT ON A FEW DEG C OF WARMING ALOFT AND LACK OF LLVL FORCING
IN THE WAKE OF THE SLOWLY NWD LIFTING WARM FRONT TO QUICKLY
DISSIPATE ANY LINGERING SHOWERS/STORMS THIS EVENING...AND LEAVE POPS
LESS THAN 20 PCT FOR THE BULK OF THE NIGHT. INCREASING CONVECTION
/OVER WRN LOWER MICHIGAN ATTM/ CRESTING THE UPPER RIDGE TO OUR WEST
COULD SNEAK INTO THE NW BY MORNING...BUT THIS IS JUST WORTH A LOW
CHC POP AT THIS POINT. MINS WILL AGAIN BE MUGGY UPPER 50S AND LOWER
60S.

TUESDAY...WE WILL BE BE WELL INTO THE WARM SECTOR AHEAD OF THE STORM
CRAWLING IN FROM THE NORTHERN PLAINS/MIDWEST/UPPER LAKES. THE WARM
SECTOR AIR WILL BE QUITE WARM FOR THIS 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...SUMMERTIME TEMPS OF UPPER 70S IN THE HILLS TO MID 80S IN
THE VALLEYS ARE EXPECTED ON TUESDAY. ALONG WITH THE WARM
TEMPERATURES...THE DEWPOINTS WILL BE SOLIDLY IN THE 60S. THIS
WARM...MOIST AIR AND A WEAKENING RIDGE MOVING OVERHEAD AND A LITTLE
TO OUR EAST WILL CREATE A GOOD SITUATION FOR SCT AFTN CONVECTION.

&&

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

WE ARE...AND WILL REMAIN BASICALLY UNDER A MEAN UPPER RIDGE...AND
THE STORM APPROACHING FROM THE WEST WILL TAKE IT/S TIME MOVING
THROUGH. SEVERE OUTLOOK FOR DAY3/WED DOES MENTION NWRN PA...CLOSE TO
THE SFC LOW AND THE BETTER UPPER FLOW. THURSDAY WILL AGAIN FEATURE
SCT/NMRS TSRA. THE MED RANGE GUID IS NOW PRETTY SOLID WITH A THURS
NIGHT/EARLY FRIDAY PASSAGE OF THE COLD FRONT ASSOCD WITH THE
SYNOPTIC SCALE STORM. MUCH COOLER AIR AND DRIER CONDITIONS SHOULD
FOLLOW FOR THE WEEKEND. ECMWF HAS BACKED OFF ON THE COLD-NESS OF THE
AIR MOVING DOWN WITH THE BIG 1030MB HIGH FOR THE WEEKEND...AND IS
MUCH CLOSER TO WHAT THE GFS HAS BEEN SAYING ABOUT THE AIRMASS. THE
ZERO C LINE AT 8H SEEMS TO STAY NORTH OF THE STATE NOW...WITH
MODIFICATION TAKING PLACE AS IT IS ALMOST SUMMER IN CANADA...TOO.

&&

.AVIATION /19Z MONDAY THROUGH SATURDAY/...
A LIGHT SOUTH-SWRLY FLOW IN THE SFC-925 MB LAYER WILL OCCUR IN THE
WAKE OF A NWD DRIFTING WARM FRONT LATE TODAY AND TONIGHT.

HIGH DEWPOINTS AND LIGHT WINDS WILL LEAD TO THE REFORMATION OF LOW
STRATUS AND AREAS OF FOG /BLO 1SM/ AFTER 06Z TUESDAY. WIDESPREAD VFR
CONDITIONS THROUGH THIS EVENING WILL STEADILY DETERIORATE TO IFR
LATE...THEN RETURN TO MVFR AND VFR BETWEEN 13-16Z TUESDAY.

SCTD SHRA AND ISOLATED TSRA LATE TODAY AND TONIGHT WILL BE LIMITED
TO MAINLY THE WRN AND NRN MTNS.

.OUTLOOK...
TUE-THU...LOW CLOUDS/FOG POSS EARLY. SCT PM THUNDERSTORM IMPACTS
POSSIBLE.
FRI AND SAT...NO SIG WX EXPECTED.

&&

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

&&

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