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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KCTP 230458
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
1258 AM EDT THU MAY 23 2013

.SYNOPSIS...
-- Changed Discussion --
LOW PRESSURE OVER SE ONTARIO WILL PASS NORTH OF PA LATER
TODAY...PUSHING A TRAILING COLD FRONT INTO PENNSYLVANIA. A
SECONDARY COLD FRONT WILL PUSH INTO THE AREA ON FRIDAY. A CANADIAN
HIGH PRESSURE SYSTEM BEHIND THE COLD FRONTS WILL USHER IN COOLER
AND DRIER AIR THAT WILL KEEP TEMPERATURES BELOW NORMAL FOR
MEMORIAL DAY WEEKEND.
-- End Changed Discussion --

&&

.NEAR TERM /UNTIL 8 AM THIS MORNING/...
-- Changed Discussion --
REGIONAL RADAR LOOP SHOWS LINGERING CONVECTION ACROSS THE EASTERN
HALF OF THE STATE HAS LARGELY DISSIPATED...AS BLYR COOLS/STABILIZES.
HOWEVER...LG SCALE FORCING AHEAD OF SHORTWAVE OVR THE OHIO VALLEY
IS SUPPORTING A BROKEN LINE OF SHRA/TSRA...WHICH IS JUST ENTERING
WESTERN PA AT 05Z. THIS MID LVL FEATURE IS PROGGED BY MDL DATA TO
WEAKEN AS IT LIFTS INTO PA BTWN 06Z-12Z...SO FOR THE OVERNIGHT EXPECT
THE BEST CHC OF A SHRA/TSRA TO BE OVR THE W MTNS BTWN 06Z-09Z.

PLENTY OF MID LVL CLOUDINESS AHEAD OF AFOREMENTIONED SHORTWAVE
SHOULD REDUCE THE CHC OF RADIATIONAL FOG...DESPITE WET GROUND AND
LGT WINDS. CLOUD COVER AND PLENTY OF LOW LVL MOISTURE SHOULD
RESULT IN COOLING OF ONLY A FEW DEG FOR THE REST OF THE NIGHT WITH
MIN TEMPS IN THE L/M 60S.
-- End Changed Discussion --

&&

.SHORT TERM /8 AM THIS MORNING THROUGH 6 PM FRIDAY/...
AREA REMAINS IN SPC SEE TEXT OUTLOOK THURSDAY. GENERALLY WEAK
INSTABILITY IS PROGGED IN THE PRE-FRONTAL WARM SECTOR...AND WILL
BE DEPENDENT ON THE EXTENT OF ANY PREFRONTAL WARMING/PARTIAL
CLEARING. MODERATE SHEAR PRESENT WHICH COULD PROMOTE A FEW
STRONGER STORMS AHEAD OF THE FRONT THU AFTERNOON...ESPECIALLY
EAST.

CONTINUED EWD PROGRESSION OF THE EXPANSIVE ERN CONUS TROUGH IS
EXPECTED THIS PERIOD...HOWEVER IT MAY BE AT SLOWER PACE AS SOME
MODEL DATA IS TRENDING SLOWER/SHARPER BY THE END OF THE PERIOD.
THE ATTENDANT COLD FRONT WILL TRAVERSE THE AREA DURING THE AFTN
AND EVENING BEFORE EXITING THE ERN PART OF THE CWA AROUND
MIDNIGHT.

A LIGHTER...DEFORMATION PCPN AXIS IS PROGGED TO SET UP OVER THE
AREA THURS NIGHT INTO FRI AS A SHORTWAVE EMBEDDED IN THE LARGER-
SCALE TROUGH DIGS FROM THE GRT LKS TWD WV. THERE ARE SOME NOTABLE
MODEL DIFFS HEADING INTO DAY 3 SURROUNDING THE DEPTH AND SPEED OF
THE H5 TROUGH CROSSING THE MID-ATLC REGION. MORE ON THIS IN THE
LONG TERM SECTION.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
EXPECT PLENTY OF CLOUDS AND LGT RAIN IN THE DEFORMATION ZONE ON
FRIDAY...WITH TEMPS FALLING BACK TO 55-65F. A BIT OF A RANGE DUE
TO THE MODEL VARIABILITY AND HAVE GONE WITH THE MODE AND TRENDED
TOWARD THE ECMWF SOLN AS IT WOULD LINGER LIGHT RAIN OVER THE AREA
/ESP IN THE EAST/ INTO SATURDAY...BUT DID NOT FULLY BUY-INTO THIS
GIVEN HOW STRONG IT WAS WITH THE CLOSED H5 LOW COMPARED TO THE
OTHER GLOBAL GUIDANCE. CANADIAN HIGH PRES EXTENDING SWD FROM
NUNAVUT INTO THE UPPER MIDWEST WILL SHIFT EWD ACRS THE GREAT LAKES
AND EVENTUALLY TAKE UP RESIDENCE OVER THE NORTHEAST BY MEMORIAL
DAY. ENS DATA CONTINUES TO SHOW NEGATIVE THERMAL/MOISTURE ANOMS
SUPPORTING AN UNSEASONABLY COOL AND DRY WEEKEND WITH THE POTENTIAL
FOR FROST IN THE NRN AND WRN MTNS SAT/SUN AM. THE GROWING SEASON
IS UNDERWAY IN THIS AREA /AS OF MAY 20TH/ AND THEREFORE WILL
CONTINUE TO MENTION FROST IN HWO. ELSEWHERE LOW TEMPS WILL BE
CHILLY BY LATE-MAY STANDARDS...BUT NOT QUITE COLD ENOUGH FOR
FROST.

Q-STNRY/WARM FRONTAL ZONE INITIALLY CENTERED FROM IA-WV SHOULD
SLOWLY RETURN NWD THROUGH THE OH VLY EARLY NEXT WEEK. GFS/EC DIFFS
IN THE PATTERN EVOLUTION CONTINUE INTO THE END OF THE MEDIUM RANGE
PARTICULARLY UPSTREAM. IN GENERAL...THERE SHOULD BE A GRADUAL
EARLY-MID WEEK WARMING TREND WITH HTS RISING AS THE UPPER TROUGH
CONTINUES TO MOVE AWAY FROM THE NORTHEAST.

&&

.AVIATION /06Z THURSDAY THROUGH MONDAY/...
A FEW MORE ADJUSTMENTS MADE.

EARLIER DISCUSSION BELOW.

ADJUSTED 00Z TAFS FOR CURRNET STORMS AND EXPECTED CONDITIONS
OVERNIGHT. AIRMASS NOT REAL HUMID...SO DID NOT HIT FOG MUCH.
DID GO WITH FOG AT LNS LATE TONIGHT.

MAIN STORM THAT RESULTED IN HIGH WINDS FORMED OVER THE MOUNTAINS
AND DRY AIR THAT HELD STORMS DOWN. HOWEVER...DRY AIR MOST LIKELY
RESULTED IN WINDS BEING STRONGER THAN WE NORMALLY SEE ON RADAR.
RADAR INDICATED WINDS TO 82 KNOTS AT 4000 FEET ABOVE MSL...2200
FEET AGL ACROSS SOUTHERN CLEARFIELD COUNTY...WEST OF STATE COLLEGE
AT 2155Z.

DID NOT PUT MUCH IN THE WAY OF SHOWERS FOR THU...EXPECT ACTION
WILL BE LATE IN THE DAY.

ADJUSTED FRIDAY OUTLOOK EARLIER...FRIDAY LOTS UGLY...COLD...
WET...AND WINDY.

AGAIN COOLER AND BREEZY FOR FRIDAY INTO SUNDAY...AS A STRONG COLD
FRONT DROPS SE OF PA.

.OUTLOOK...
FRI...LOW CIGS ETC...WITH SHOWERS AND PERHAPS A FEW STORMS.
SAT-MON...NO SIG WX EXPECTED.

&&

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

&&

$$
SYNOPSIS...DANGELO/FITZGERALD
NEAR TERM...FITZGERALD
SHORT TERM...DEVOIR/STEINBUGL
LONG TERM...CERU
AVIATION...DEVOIR/MARTIN