Area Forecast Discussion
Issued by NWS State College, PA

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FXUS61 KCTP 290300
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
1100 PM EDT THU MAY 28 2015

.SYNOPSIS...
SUMMER-LIKE CONDITIONS WITH ABOVE NORMAL TEMPERATURES WILL COME
TO AN END BY THE END OF THE MONTH AS A COLD FRONT MOVES ACROSS
CENTRAL PENNSYLVANIA THIS WEEKEND. THE FRONTAL PASSAGE WILL
LIKELY BE ACCOMPANIED BY SHOWERS AND THUNDERSTORMS. THE FRONT IS
EXPECTED TO STALL NEAR THE MASON DIXON LINE WHICH SHOULD FAVOR A
COOLER WEATHER PATTERN TO START THE MONTH OF JUNE.

&&

.NEAR TERM /UNTIL 7 AM FRIDAY MORNING/...
ALL RADAR RETURNS STAYING SOUTH OF THE MD BORDER. LOWER SUSQ SIES
MAY SEE LIGHT FOG IN THE MORNING AS IT SHOULD BE MAINLY CLEAR - AT
LEAST EARLY - WITH DEWPOINTS A BIT HIGHER THAN ELSEWHERE IN THE
CWA. SFC WINDS MAY START TO VEER AROUND TO THE SE-S BY THE END OF
THE NIGHT AND BE AROUND 10 MPH OVER THE HIGH TERRAIN OF THE
LAURELS. WILL GO WITH NIL POPS. INTERESTING CREEPING LOWER-VFR
CLOUDS JUST INTO SRN SOMERSET CO NOW. WILL INCREASE CLOUD/SKY
COVER FOR OVERNIGHT USING CONCEPT OF UPSLOPE SE WINDS COMING FROM
AREA WHICH HAD SOME SHOWERS EARLIER TODAY AND NAM RH PROFILE AS A
GUIDE. MOST OF THE MOISTURE IS WELL-ALOFT THOUGH. WHILE THE MESO
MDLS CONTINUE TO GENERATE SOME CONVECTION IN THE FAR SE...HAVE TO
DISCOUNT IT BASED ON THE OVER- DONE COVERAGE FCSTS THEY HAD IN FOR
THIS AFTN/EVENING OVER PA AND NO SFC INSTABILITY. S/B A
COMFORTABLE NIGHT FOR ALMOST ALL THE AREA.

&&

.SHORT TERM /7 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/...
THE AFOREMENTIONED RETURN SOUTHERLY FLOW WILL DRAW THE
HUMID/UNSTABLE AIR MASS BACK INTO THE AREA FRIDAY...SUPPORTING
SCATTERED DIURNAL PM CONVECTION. LIGHT WINDS BENEATH UPPER LVL
RIDGE SHOULD RESULT IN NORTHWARD-DRIFTING PULSE TYPE TSRA WITH
LITTLE THREAT OF SVR WX. MDL SOUNDINGS SUPPORT MAX TEMPS IN THE
L80S MOST PLACES...WITH THE GREATEST DEPARTURES FROM AVG ACROSS
WARREN CO DUE TO DOWNSLOPING SSE FLOW. BEST CHC OF CONVECTION
WILL BE TO THE WEST CLOSER TO THE RING OF FIRE...AND OVER
ELEVATED HEAT SOURCES FRI AFTN. HIGHS WILL RANGE THROUGH THE
LOWER TO MIDDLE 80S FROM NORTH TO SOUTH.

&&

.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
HIGH PRESSURE AT THE SFC AND ALOFT WILL ALLOW FOR SUBSIDENCE ONCE
DAYTIME HEATING DIMINISHES FRIDAY EVENING. THERE IS A SLIGHT
CHANCE FOR TOPOGRAPHIC FORCING TO ALLOW FOR A SLIGHT CHANCE OF
PRECIPITATION FRIDAY NIGHT INTO SATURDAY THROUGH THE CENTRAL AND
NORTHWESTERN MOUNTAINS. THE REST OF FRI NIGHT SHOULD BE FAIR AND
SUMMERLIKE WITH HIGH DWPTS ALLOWING TEMPS TO FALL ONLY INTO THE
60S.

MED RANGE GUIDANCE SIGNALS A CONTINUATION OF SUMMERLIKE WX
INTO SATURDAY...WITH 12Z GEFS SHOWING ANOMALOUS 500MB HGTS AND
SFC PRES OFF THE E COAST. HOWEVER AS SATURDAY CONTINUES THE HIGH
WILL BE SHIFTED EASTWARD AND A LARGE UPPER LEVEL TROUGH WILL MOVE
A FAIRLY STRONG BOUNDARY THROUGH CENTRAL PA. THE MODELS VARY IN
THE TIMING BUT THERE WILL BE A BETTER CHC OF SHRA/TSRA BY MID TO
LATE SATURDAY WITH APPROACH OF A COLD FRONT. THE LARGER MODEL
TIMING DIFFS HAVE BEEN RESOLVED WITH MODEL CONSENSUS NOW PUSHING
COLD FRONT THRU SUN MORNING.

IN WAKE OF THE FRONT...A COUPLE DAYS OF CLOUDY...COOL AND SHOWERY
WX APPEARS ON TAP FOR CENTRAL PA WITH FRONT STALLING OUT SOUTH OF
PA AND A LIKELIHOOD OF OVERRUNNING RAIN/SHOWERS. ANOMALOUS
EASTERLY FLOW/PWATS INDICATED IN 12Z GEFS OVER CENTRAL PA BTWN
SFC HIGH OVR NEW ENG AND FRONT TO THE SOUTH. IN ADDITION TO THE
MOISTURE...CENTRAL PA WILL REMAIN IN FAVORABLE JET ENTRANCE REGION
SUN-MON..PROVIDING THE LG SCALE FORCING TO SUPPORT PERIODS OF
RAIN SUN-MON..12Z GEFS MEAN QPF BTWN SUN-MON RANGES FROM 0.5 TO 1
INCHES. THE MODELS HAVE SHIFTED THE TIMING OF THE MOISTURE POOL
SHIFTING IT SOUTH OF THE MASON DIXON. THIS HOWEVER COMES IN
CONJUNCTION WITH AN INFLUX OF COLDER AIR AS A SFC HIGH BUILDS
OVER EASTERN CANADA.

HAVE CONTINUED TO LOWERED THE MAX TEMPS THROUGH THE FIRST HALF OF
NEXT WEEK AND LOWERED POPS ACCORDINGLY. IMPROVING CONDS APPEAR
LIKELY THROUGH MOST OF THE WORK WEEK AS UPPER RIDGE CONTINUES TO
BUILD AND EXPAND NORTHWARD INTO PA.

&&

.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
03Z TAF UPDATE.

NO MAJOR CHANGES MADE.

MAINLY LOOKING AT SOME HIGH CLDS OVERNIGHT. MOST AREAS SHOULD
REMAIN VFR. HOWEVER...DEWPOINTS HIGHER AT LNS...THUS ADDED SOME
FOG TO THE FCST FROM 10Z TO 13Z FRIDAY MORNING.

SOME SHOWERS POSSIBLE FAR WESTERN AREAS LATER ON FRIDAY...THUS
HAVE VCSH IN FOR BFD AND JST.

OUTLOOK...

SAT...PATCHY MVFR FOG/CIGS EARLY. SCT-NMRS AFTERNOON TSTMS W/COLD
FROPA.

SUN-TUE...VFR/MVFR CONDS WITH SCT SHOWERS/TSTMS.

&&

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

&&

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



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