-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KCTP 210853
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
453 AM EDT MON JUL 21 2014

.SYNOPSIS...
AN UPPER LEVEL WILL SLIDE EAST ACROSS PENNSYLVANIA TODAY. A COLD
FRONT WILL MOVE SOUTHEAST FROM THE GREAT LAKES AND CROSS THE
COMMONWEALTH LATE WEDNESDAY AND WEDNESDAY NIGHT. A REFRESHINGLY
COOLER AND LESS HUMID AIRMASS WILL OVERSPREAD THE COMMONWEALTH
THURSDAY THROUGH SATURDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
08-0830Z KCCX RADAR LOOP SHOWS SCATTERED LIGHT SHOWERS DRIFTING
NE ACROSS THE LAUREL HIGHLANDS REGION FROM WVA /IN ASSOCIATION
WITH A WEAK SHORT WAVE IN THE SW FLOW ALOFT...AHEAD OF AN UPPER
LEVEL SHEAR AXIS THAT WAS LOCATED ACROSS THE OHIO VALLEY/.

ANOTHER VORT MAX WILL BE DIVING SE TWD THE BASE OF THE WEAK UPPER
LEVEL TROF...AND MOVING ACROSS THE NW MTNS DURING THE AFTERNOON
AND EARLY EVENING HOURS. POCKETS OF UVVEL ASSOCIATED WITH BOTH OF
THESE FEATURES WILL COMBINE WITH AN AXIS OF HIGH PWAT AIR
/1.5-1.75 INCHES/ TO CREATE SCATTERED SHOWERS AND ISOLATED
AFTERNOON TSRA.

THE GREATEST CONCENTRATION OF CONVECTION IS EXPECTED TO BE ACROSS
THE LAURELS /AND TO A LESSER DEGREE OVER THE NRN MTNS/ WHERE
SLIGHTLY COOLER MID-LEVEL TEMPS AND A LIGHT SERLY LLVL UPSLOPE
FLOW WILL BE FOUND. THIS SCENARIO IS SUPPORTED BY A BLEND OF THE
LATEST 06Z HRRR...07Z RAP...AND 03Z SREF WHERE ML CAPES OF
800-1200 J/KG ARE SHOWN. CONVECTIVE INSTAB ELSEWHERE ACROSS
CENTRAL AND NERN PA IS MINIMAL.

BASIN AVG QPF WILL BE GENERALLY ONE TENTH OF AN INCH OR LESS
ACROSS THE WRN HALF OF THE CWA...THOUGH SOME AREAS COULD SEE
AROUND 0.25 OF AN INCH /ESP NEAR AND TO THE SOUTH OF KJST/.

OTHERWISE...LIGHT WIND WITH TVARIABLE AMOUNTS OF HIGH BASED
STRATOCU AND ALTOCU CLOUDS /AND AREAS OF LIGHT FOG ACROSS THE
NORTH/ WILL OCCUR THIS MORNING WITH JUST AN ISOLATED SHOWER
POSSIBLE ACROSS THE NE HALF OF THE CWA.

CONSENSUS BLEND OF ALL AVAILABLE 00Z THROUGH 06Z GUIDANCE
YIELDS HIGH TEMPS THIS AFTERNOON RANGING FROM THE UPPER 70S TO
LOW 80S...WHICH IS A TAD COOLER THAN NORMAL FOR MID SUMMER.
SFC DWPTS CLIMBING WELL INTO THE 60S WILL ALSO MAKE IT FEEL
MORE MUGGY.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/...
A VERY SIMILAR NIGHT /TO SUNDAY NIGHT/ IS EXPECTED WITH JUST SOME
ISOLATED /MAINLY EVENING/ SHOWERS...FOLLOWED BY PARTLY CLOUDY
SKIES WITH NEAR NORMAL MIN TEMPS RANGING FROM THE U50S IN THE
NORTH...TO THE LOWER 60S THROUGHOUT THE CENTRAL MTNS...AND MID
60S ACROSS THE LOWER SUSQ RVR VALLEY.

TUESDAY WILL BE NOTICEABLY WARMER AND HUMID WITH PARTLY SUNNY
SKIES AND APPROX 1.5 PWAT AIR HELPING TO FUEL ML CAPES OF 800-1400
J/KG ACROSS THE WRN MTNS...AND GENERALLY LESS THAN 500 J/KG ACROSS
THE MIDDLE AND LOWER SUSQ VALLEY.

UNIMPRESSIVE...MID-LEVEL LAPSE RATES OF JUST OVER 5C/KM WILL KEEP
MOST OF THE CONVECTION ISOLATED /AND ACROSS THE HIGHER TERRAIN OF
NRN AND WRN PENN/ DURING THE AFTERNOON AND EVENING HOURS.

HIGH TEMPS TUESDAY AFTERNOON WILL BE IN THE LOWER 80S ACROSS THE
MTNS...AND MID TO UPPER 80S THROUGHOUT THE VALLEYS OF CENTRAL AND
SOUTHERN PENN.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
LARGE UPPER RIDGE BUILDING NORTH OVER THE FOUR CORNERS REGION IS
FORECAST TO EXPAND NORTH AND EAST INTO THE ROCKIES AND PLAINS
DURING THE PERIOD. DOWNSTREAM...THIS WILL LEAD TO WEAK LONG WAVE
TROFFING OVER THE EASTERN THIRD OF THE COUNTRY. UPPER LOW TO THE
EAST OF HUDSON BAY WILL BE STRENGTHENED AT TIMES BY SHORTWAVE
ENERGY IN THE STRONGER JET STREAM FLOW ACROSS CANADA. SOUTHWARD
EXTENSION OF THIS LOW/TROF WILL AT TIMES DURING THE PERIOD
STRENGTHENING THE TROFFING ACROSS THE NORTHEASTERN U.S./OUR
REGION.

MEDIUM RANGE MODEL FORECASTS CONTINUE TO BRING A FRONT AND
INCREASED CHANGES FOR PRECIPITATION TOWARD PA IN THE
WEDNESDAY/THURSDAY TIME FRAME AND SHOW ANOTHER...POTENTIALLY
STRONGER SYSTEM LATE NEXT WEEKEND.

IN THE MEANTIME...SURFACE HIGH PRESSURE AXIS TO OUR EAST WILL
KEEP GENERALLY FAIR WEATHER ACROSS PENNSYLVANIA EARLY IN THE WEEK.

LOW LEVEL MOISTURE WILL ATTEMPT TO CREEP BACK INTO THE REGION
ON WEAK RETURN FLOW MONDAY NIGHT AND TUESDAY. DEEPEST MOISTURE
WILL REMAIN FARTHER WEST OVER OHIO VALLEY. KEPT MENTION OF ISO/SCT
TSTMS MON- EARLY WED /MAINLY ACROSS THE WEST/.

A WARMING TREND BEGINNING ON MONDAY...WILL CONTINUE RIGHT THROUGH
WED...WHEN TEMPS ARE EXPECTED REACH THEIR PEEK FOR THE WEEK IN
THE IN THE UPPER 80S TO AROUND 90F IN THE SUSQ VALLEY...AND
GENERALLY IN THE MID 80S ELSEWHERE.

&&

.AVIATION /08Z MONDAY THROUGH FRIDAY/...
GENERALLY FOLLOWED A BLEND OF PERSISTENCE /LAST NIGHTS SFC OBS
AND EARLY MORNING TRENDS/ WITH CURRENT CONDS FOR THE 21/06Z
SCHEDULED TAFS. DESPITE RELATIVELY HIGH BLYR MSTR/THIN T-TD
SPREADS...COMBO OF SCT-BKN MID CLOUDS WITH LACK OF OBSERVED RAFL
SEEMS TO BE KEEPING RESTRICTIONS AOA MVFR FLGT CATS. MVFR TO LOW
END VFR CIGS AND VSBYS SHOULD IMPROVE TO VFR /SCT-BKN CU WITH
BASES AROUND 5KFT AGL/ BY LATE MORNING/AFTN.

LIFT ASSOCD WITH LEFTOVER BROAD/WEAK UPPER TROUGH CENTERED JUST
WEST OF THE APPALACHIAN SPINE...COUPLED WITH MEAGER INSTABILITY
SHOULD BE ENOUGH TO GENERATE WDLY SCT SHRA/ISOLD TSRA ACRS THE
AIRSPACE THIS AFTN. CVRG AND PROBS OF PCPN ARE TOO LOW TO MENTION
IN POINT BASED TAFS ATTM. PARTIAL CLEARING EXPECTED WITH THE LOSS
OF DAYTIME HEATING...GIVING WAY TO PATCHY FOG/LOWERING CIGS
OVERNIGHT MAINLY E OF THE ALLEGHENY FRONT.

OUTLOOK...

TUE...MAINLY VFR. SCT A.M MVFR FOG/CIGS. WDLY SCT AFTERNOON AND
EVENING SHOWERS/THUNDERSTORMS.

WED-THU...SLOW NW-SE MOVG COLD FROPA WILL LKLY BRING SCT SHOWERS
AND THUNDERSTORMS.

FRI...NO SIG WX.

&&

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

&&

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