Area Forecast Discussion
Issued by NWS State College, PA

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FXUS61 KCTP 270356
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
1156 PM EDT TUE MAY 26 2015

.SYNOPSIS...
HIGH PRESSURE AT THE SFC AND ALOFT WILL REMAIN ANCHORED JUST OFF
THE EAST COAST THROUGH THE END OF THIS WEEK. A COLD FRONT WILL
LIKELY PUSH ACROSS THE REGION SATURDAY NIGHT...THEN STALL JUST
SOUTH OF THE STATE EARLY NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
1015 PM UPDATE...
MESOSCALE CONVECTIVE COMPLEX IS MOVING INTO FAR EASTERN OHIO...BUT
WEAKENING AS IT DOES SO. MOST OF THE VERY SPARSE CONVECTION THAT
DID FORM THIS EVENING DIES VERY QUICKLY OVER CENTRAL PA. THE
WARMER TEMPS ALOFT CLOSER TO THE UPPER RIDGE AND THE LOSS OF
DAYTIME HEATING WILL MOST LIKELY WEAKEN THIS STUFF EVEN FURTHER.
SOME/SLIGHT DEVELOPMENT IS SEEN AT THIS TIME ON THE SRN
FLANK. IF THIS DIMINISHES AS WELL...LITTLE TO NO PRECIP WILL GET
INTO THE CWA...OR CERTAINLY CROSS RTE 219 BEFORE DAYBREAK. WILL
PAINT LOW POPS IN FOR THE WEST AND NIL FOR THE EAST. WHILE A VERY
ISOLATED SHOWER MAY POP OVER THE CENTRAL MTNS OR SUSQ VALLEY...IT
IS NOT WORTH POPS AT THIS POINT. A MUGGY AND WARM NIGHT IS IN
STORE AND SOME FOG IS POSSIBLE IN THE MORNING.

PREV...
DEEP SOUTH-SOUTHWESTERLY FLOW ON THE WESTERN PERIPHERY OF THE
DOMINANT COAST RIDGE WILL CONTINUE TO TRANSPORT GULF OF MEX
MOISTURE NORTHWARD INTO CENTRAL PA.

WATER VAPOR LOOP AND RAP 300-400 MB WIND PROGS INDICATE THAT A
WELL-DEFINED...ALBEIT COMPACT SHORT WAVE WILL BE MOVING NE ACROSS
LAKE ERIE LATE THIS AFTERNOON...WHILE AN ASSOCIATED 45-50 KT
JETLET CROSSES NRN AND WRN PENN.

ENHANCED MESOSCALE LIFT FROM THIS FEATURE WILL TEAM UP WITH THE
GROWING CAPE VALUES /LOCALLY AS HIGH AS 1000-1500 J/KG/ ACROSS
THE ALLEGHENY PLATEAU TO PRODUCE INCREASINGLY NUMEROUS
SHOWERS...AND A FEW TSRA LATE THIS AFTERNOON AND EARLY THIS
EVENING.

BLEND OF THE LATEST NAM/SREF AND HRRR CONTINUE TO FAVOR THE NRN
MTNS...AND PORTIONS OF THE LAUREL HIGHLANDS FOR THE GREATEST CHC
OF SHOWERS/SCTD TSRA.

FOR AREAS SOUTH AND EAST OF KCBE TO KSEG AND KAVP LINE...THE
PERIOD THROUGH 21Z SHOULD REMAIN DRY. HOWEVER...DIFFERENTIAL
HEATING AT THE SE EDGE OF THE MID LEVEL CLOUD SHIELD...AND A
RIBBON OF HIGHEST 850 MB THETA-E AIR ADVECTING EAST INTO THE
MIDDLE SUSQ VALLEY SHOULD HELP TO FOCUS AND ENHANCE ANOTHER AREA
OF SHOWERS THERE LATE TODAY.

SPC PAINTS THEIR MARGINAL RISK OF SVR TSRA ACRS ROUGHLY THE WRN
HALF OF PENN THIS AFTERNOON AND EVENING.

BASIN AVG RAINFALL WILL BE GENERALLY AROUND 0.10 OF AN INCH IN
MOST PLACES THROUGH MIDNIGHT...WITH SOME SPOTTY 0.25-0.50 INCH
AMOUNTS IN TSRA.

TEMPS ARE NEARING THEIR HIGHS FOR THE DAY RANGING FROM THE MID-
UPR 70S OVR THE ALLEGHENY PLATEAU...TO THE M80S ACROSS THE LOWER
SUSQ VALLEY.

&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/...
A POTENT SHORTWAVE LIFTING THRU THE GRT LKS WILL INTRODUCE A
BETTER CHC OF SHRA/TSRA ON WEDNESDAY. MDL TIMING OF THIS FEATURE
SUGGESTS SHOWERS COULD ARRIVE EARLY IN THE DAY ACROSS THE W
COUNTIES...WITH A GREATER RISK OF PM TSRA ACROSS EASTERN PA.

GEFS MEAN CAPES PEAK ARND 1200 J/KG ACROSS THE SE COUNTIES WED
AFTN. HOWEVER...MID LVL WINDS AND ASSOCIATED DEEP-LYR SHEAR ARE
NOT PARTICULARLY STRONG IN THE LATEST MDL DATA...SO THE SVR WX
THREAT JUST MRGL...AND THAT`S WHAT SPC COVERS PRACTICALLY ALL OF
THE CWA WITH IN THEIR DAY 2 CONVECTIVE OUTLOOK.

MCLDY SKIES WILL HOLD TEMPS DOWN A BIT...BUT CONSALL STILL
SUGGESTS HIGH TEMPS BTWN THE M70S- L80S...SEVERAL DEG ABV NORMAL
FOR LATE MAY.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
UPPER LEVEL TROUGH WILL DEEPEN AS IT PROPAGATES EASTWARD. EXPECT
COLD FRONT TO MOVE THROUGH PA...WEDNESDAY NIGHT INTO THURSDAY
MORNING. THIS WILL BRING NORTHWESTERLY FLOW AND COOLER AND DRIER
AIR. HIGH PRESSURE AT THE SURFACE AND ALOFT WILL BUILD OVER THE
REGION THROUGH FRIDAY...REDUCING ANY PRECIPITATION CHANCES THROUGH
THE LATTER HALF OF THE WEEK AS THE BULK OF MED RANGE GUIDANCE
IMPLIES DRIER WX AS LOWER PWAT AIR MASS WORKS INTO CENTRAL PA.

A COLD FRONT WILL LIKELY BRING AN END TO THE SUMMER-LIKE
WARMTH/HUMIDITY NEXT WEEKEND. A FAIR AMT OF AGREEMENT AMONG MED
RANGE GUIDANCE FOR RAINY WX SATURDAY NIGHT INTO SUNDAY ALONG AN
INCOMING FRONTAL BOUNDARY. SCATTERED SHOWERS COULD FOLLOW SUNDAY/MONDAY
AS WAVE OF LOW PRES RIDES EASTWARD ALONG STALLED FRONTAL BNDRY
SOUTH OF PA.

&&

.AVIATION /04Z WEDNESDAY THROUGH SUNDAY/...
A SUMMER-TIME PATTERN WILL PERSIST THROUGH THE WEEK.

RADAR CONTINUES TO BE QUIET ACROSS CENTRAL PA AT 04Z...THOUGH SOME
CONVECTION BEGINNING TO EDGE EASTWARD ACROSS THE OH/PA BORDER INTO
W PA. MAJORITY OF CWA WILL REMAIN DRY OVERNIGHT...BUT SOME SHOWERS
MAY SLIP INTO FAR WESTERN COUNTIES FROM KBFD-KJST AFTER 10Z. VFR
CONDITIONS HAVE BEEN THE RULE SO FAR /EXCEPT AT KIPT WHERE RAIN
FELL LATE TUE AFTERNOON/ BUT AS SUNRISE APPROACHES AND MOIST LOW
LEVEL FLOW PICKS UP A BIT...EXPECT MVFR CIGS/VSBY TO DEVELOP OVER
MUCH OF CWA.

SREF MODEL GUIDANCE SUGGESTS /AND EVEN NAM MOS HINTS/ THAT THE
LOWER CIGS MAY LINGER INTO LATE MORNING FROM KIPT-KMDT BEFORE A
RETURN TO VFR...MID MORNING ELSEWHERE. CHANCES FOR
SHOWERS/ISOLATED TSTMS PEAK ACROSS WESTERN HALF OF CWA BETWEEN
12-18Z...AND SLIDE EASTWARD AFTER 16Z.

OUTLOOK...

WED...PATCHY A.M. MVFR FOG/BR. SCT SHOWERS/TSTMS.

THU-FRI...PATCHY A.M. MVFR FOG/BR. ISOLD P.M. TSTMS.

SAT...PATCHY A.M. MVFR FOG/BR. SCT-NMRS P.M TSTMS W/COLD FROPA.

SUN...MVFR CIGS POSS NW. OTHERWISE MAINLY VFR IN SCT SHOWERS.

&&

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

&&

$$
SYNOPSIS...LAMBERT
NEAR TERM...DANGELO/LAMBERT
SHORT TERM...FITZGERALD/LAMBERT
LONG TERM...FITZGERALD/CERU
AVIATION...LAMBERT/RXR


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