Area Forecast Discussion
Issued by NWS State College, PA

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000
FXUS61 KCTP 280950
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
550 AM EDT TUE JUL 28 2015

.SYNOPSIS...
SUMMERTIME HEAT AND HUMIDITY WILL BE THE MAIN WEATHER STORY
IN CENTRAL PENNSYLVANIA THROUGH MIDWEEK. A WELL-DEFINED COLD
FRONT WILL MOVE ACROSS THE APPALACHIANS AND MID-ATLANTIC STATES
ON THURSDAY ACCOMPANIED BY SOME STRONG TO SEVERE THUNDERSTORMS.
SEASONABLY WARM AND MAINLY DRY WEATHER WILL CLOSE OUT JULY 2015
AND CONTINUE INTO THE FIRST WEEKEND IN AUGUST.

&&

.NEAR TERM /THROUGH TONIGHT/...
10Z...VISBYS HAVE DECLINED OVER THE LAST FEW HOURS AS FOG HAS
BECOME MORE WIDESPREAD. OPTED FOR SPS VS. DENSE FOG ADVY WITH NOT
ALL SITES 1/4SM OR LESS. THE FOG AND SHALLOW STRATUS LAYER WILL
CONTINUE TO IMPACT THE EARLY MORNING COMMUTE BEFORE BURNING OFF
BTWN 8-9AM. ONCE THE FOG IS GONE...EXPECT ABUNDANT SUNSHINE WITH
HIGH TEMPERATURES IN THE MID TO UPPER 80S.

A MOIST UNSTABLE AIRMASS WILL REMAIN IN PLACE ALONG AND SOUTH OF A
WEAK FRONTAL BOUNDARY EXTENDING WEST TO EAST FROM THE OH RIVER TO
AROUND THE MASON DIXON LINE. A CONSENSUS OF HIGH RES MODEL DATA
SHOWS ISOLD SLOW MOVG AIRMASS TYPE TSTMS DEVELOPING FROM FAR
SOUTH CENTRAL PA INTO NRN WV/MD PNHDLS...LKLY AIDED BY ELEVATED
HEAT SOURCES OR TERRAIN INDUCED LIFT. PWS BTWN 1-1.5 INCHES
SUGGEST SOME LOCALLY HEAVY DOWNPOURS ARE POSSIBLE...BUT WILL KEEP
POPS AOB 20 PCT GIVEN LIMITED COVERAGE. THE BEST CHC APPEARS TO BE
SOUTH OF THE PA/MD LINE WHERE BETTER MSTR/INSTABILITY WILL RESIDE
NEAR THE AFOREMENTIONED DIFFUSE FRONTAL BOUNDARY. HIGH PRESSURE
WILL PROVIDE ANOTHER M/CLR NIGHT WITH PATCHY FOG IN THE VALLEYS.

&&

.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
WEDNESDAY LOOKS PRETTY SIMILAR TO TODAY WITH ANOTHER VERY WARM
AND HUMID DAY ACROSS CENTRAL PA. FCST HIGHS ARE A FEW DEGREES
WARMER WITH SEVERAL LOCATIONS LKLY REACHING 90F. HEAT INDEX VALUES
SHOULD REACH 95F OVER THE LOWER SUSQ VLY. A SLIGHT INCREASE IN PWS
WILL BE COUNTERED A FEW DEGREES OF WARMING ALOFT WHICH MAY PROVIDE
A TSTM CAP WITH H7 TEMPS NEAR +10C. STILL CANT RULE OUT AN ISOLD
TSTM OVER THE SOUTH CENTRAL RIDGES...BUT AGAIN EXPECT THE OVERALL
COVERAGE BE VERY ISOLD AT BEST. WED NGT WILL BE WARM AND MUGGY
WITH LOWS AROUND 70F EAST OF THE ALLEGHENY MTNS. A MODEST SURGE IN
LOW TO MID LVL THETA-E ADV ASSOCD WITH WSWLY H85 LLJ AXIS
PRECEDING A COLD FRONT MOVG ESEWD ACRS THE GREAT LAKES/OH VLY
WILL SUPPORT CHC OF SHOWERS/TSTMS LATE WED NGT INTO EARLY THURS
MORNING ACROSS THE WRN 1/3 OF THE CWA.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
WEAK HEIGHT FALLS ARE EXPECTED TO OVERSPREAD CENTRAL PENNSYLVANIA
THURSDAY/D3...ON THE SOUTHERN PERIPHERY OF A LARGE SCALE TROUGH
AMPLIFYING OVER EASTERN CANADA AND EVENTUALLY THE GREAT LAKES AND
NORTHEAST STATES. EARLY-DAY WAA CLOUD COVER/SHOWERS WILL LIKELY
PRECEDE THE EWD-ADVANCING COLD FRONT...BUT POCKETS OF STRONGER
HEATING AND RELATED WEAK TO MODERATE INSTABILITY SHOULD PROMOTE
SCT-NMRS TSTM DEVELOPMENT DURING THE AFTERNOON ACROSS CENTRAL TO
EASTERN PORTIONS OF THE CWA. ASSUMING SUFFICIENT DESTABILIZATION
OCCURS...30-40KT DEEP LAYER SHEAR VALUES WOULD BE SUPPORTIVE OF
AT LEAST SEMI-ORGANIZED STORM MODES AND MARGINAL RISK OF DAMAGING
WINDS. WILL ADD THE DAY 3/THU SEVERE WEATHER RISK TO THE HWO. MAX
TEMPS ON THURS WILL STILL BE VERY WARM WITH HIGHS AROUND 90F EAST
OF THE ALLEGHENY MTNS. HEAT INDEX VALUES MAY APPROACH 100F ACROSS
THE LOWER SUSQ VLY.

MAINLY DRY WEATHER WITH LOWER HUMIDITY IS EXPECTED IN THE WAKE OF
THE FRONTAL PASSAGE FROM FRI-MON. TEMPERATURES WILL REMAIN NEAR TO
ABOVE CLIMATE NORMALS HEADING INTO THE FIRST WEEKEND OF AUGUST.

&&

.AVIATION /10Z TUESDAY THROUGH SATURDAY/...
HIGH PRESSURE WILL SLOWLY BUILD OVER THE REGION AS THE WINDS
OVERNIGHT BECOME DECOUPLES. EXPECT AS THE WINDS LIGHTEN...AND THE
TEMPERATURES DROP...LOWERING THE DEWPOINT DEPRESSION...PATCHY
FOG/MIST AND LOW STRATOCU WILL CONTINUE TO DEVELOP. PATCHY
FOG/MIST AS ALREADY FORMED AND MOVED OVER UNV..WITH LIFR CIGS AND
VSBYS. LIKEWISE IFR AT LNS AND SEG HAS DEVELOPED. EXPECT THIS TO
CONTINUE AT ALL TAF SITES...WITH REDUCING CONDITIONS CONTINUING
OVERNIGHT THROUGH 12Z. SO WIDESPREAD IFR WITH LOCALIZED LIFR CIGS
AND VSBYS WILL OCCUR IN DENSE FOG.

THE REDUCING CONDITIONS WILL SLOWLY DISSIPATE TUESDAY
MORNING...WITH TEMPO GROUPS POSSIBLE AS THE CONDITIONS SLOWLY
IMPROVE BETWEEN 12Z TO 15Z.

AFTER THE FAIRLY WIDESPREAD FOG/STRATUS SLOWLY LIFTS AND
DISSIPATES AWAY TUES...THERE SHOULD NOT BE MUCH IN THE WAY OF
CLOUDS AS UPSTREAM RIDGING GETS NEARER.

OUTLOOK...

WED...MAINLY VFR.
THU...CFROPA W/VERY BRIEF REDUCTIONS DUE TO TSRA.
FRI...MAINLY VFR.
SAT...MAINLY VFR AM...SHRA/TSRA POSS NW.

&&

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

&&

$$
SYNOPSIS...STEINBUGL
NEAR TERM...STEINBUGL
SHORT TERM...STEINBUGL
LONG TERM...STEINBUGL
AVIATION...LAMBERT/CERU



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