Area Forecast Discussion
Issued by NWS State College, PA

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FXUS61 KCTP 270136
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
936 PM EDT TUE AUG 26 2014

.SYNOPSIS...
HIGH PRESSURE WILL YIELD TO A COLD FRONT THAT WILL SAG THROUGH THE
REGION WEDNESDAY. DRY WEATHER WITH LOW HUMIDITY...AND
TEMPERATURES SEVERAL DEGREES BELOW NORMAL WILL RETURN FOR LATE
WEEK.

&&

.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
CLEAR SKIES PREDOMINATE THIS EVENING...AS UPPER RIDGE AND 590+ DM
500 MB HEIGHTS COVER THE SOUTHWEST HALF OF CENTRAL PA THIS
EVENING. CONVECTIVE DEBRIS THE UPPER RIDGE FLATTENS OVER THE
EASTERN GLAKS OVERNIGHT IN RESPONSE TO FAST MOVING SHORTWAVE TROF
EMBEDDED IN ZONAL FLOW EJECTING FROM THE CANADIAN ROCKIES THIS
AFTERNOON...WHICH REACHES LAKE SUPERIOR BY 12Z WED MORNING.

AS A RESULT...EVENING CLEAR SKIES WILL GRADUALLY BE OVERTAKEN BY
INCREASING CLOUDS FROM NORTHWEST TO SOUTHEAST BEGINNING LATER
THIS EVENING OVER THE NORTHWEST MOUNTAINS...WITH MOSTLY CLOUDY
CONDITIONS REACHING THE CENTRAL MOUNTAINS BY 12Z. MINS WILL
CORRESPONDINGLY BE A FEW DEGREES WARMER THAN TUE MORNING READINGS.
HOWEVER...INITIALLY CLEAR SKIES AND LIGHT WINDS WILL PROMOTE THE
DEVELOPMENT OF AREAS OF VALLEY FOG...GENERALLY AFTER MIDNIGHT.
MIN TEMPS WILL BE NEAR 60.

&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/...
SHORT TERM OPERATIONAL MODELS AGREE IN SAGGING A COLD FRONT DOWN
THROUGH THE FORECAST AREA DURING THE DAY WEDNESDAY. THE DWINDLING
RIBBON OF ANOMALOUSLY HIGH PWAT AIR INDICATES THE FRONT WILL BE
WEAK AND WEAKENING FURTHER AS IT MOVES THROUGH.

MAIN CONCERN WILL BE FOR CONVECTION WHICH SEEMS LIKE IT WILL HAVE
SOME CAPE TO WORK WITH. THE WIND FIELDS ARE FORECAST TO BE
WEAK...SO THE SEVERE THREAT SHOULD NOT BE WIDESPREAD...BUT CANNOT
RULE OUT A STRONG WIND GUST OR SOME MARGINALLY SEVERE HAIL IN SOME
OF THE MORE ROBUST UPDRAFTS. OPERATIONAL NAM COOKS UP CAPES IN
EXCESS OF 2000J WHILE THE SREF AND GEFS ARE MORE MODEST...BUT
STILL NOT NEGLIGIBLE.

IT WILL BE ANOTHER VERY WARM DAY WITH HIGHS POSSIBLY NUDGING 90
FOR THE LAST TIME THIS SEASON OVER THE SERN PART OF THE FCST AREA.
THE BULK OF THE REMAINDER OF THE AREA WILL REACH 80 OR ABOVE.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
UPPER RIDGE IS FORECAST TO SURGE NWD ALONG THE EAST COAST INTO
THE EARLY WEEKEND AS SHORTWAVE ENERGY SUPPORTING WEDNESDAY FROPA
LIFTS OUT.

THIS RIDGING...ACCOMPANIED BY HIGH PRESSURE SLIDING ACROSS NEW
ENGLAND WILL BRING A RETURN TO DRY CONDITIONS FOR LATE THIS WEEK.
AS THE HIGH MOVES OFF OF THE COAST RETURN SLOW WILL HELP PULL THE
FRONT FROM EARLIER IN THE WEEK NORTHWARD INTO WESTERN PA ON
SATURDAY. AFTERNOON HIGH TEMPS NEAR NORMAL ON FRIDAY WILL SURGE TO
5 TO 10 DEGREES ABOVE NORMAL OVER THE WEEKEND.

NEXT SHORTWAVE TROF IN THE NORTHERN STREAM FLOW IS PROGGED TO
EMERGE FROM THE PLAINS ON FRIDAY AND LIFT TO EASTERN ONTARIO BY
SUNDAY. THIS WILL SUPPORT A COLD FRONT REACHING NRN PA ON SUNDAY.
MODEL TRENDS HAVE BEEN TO SLOW THE ARRIVAL OF THE FRONT AND TO
TALL THE SOUTHWARD PROGRESS OF THE FRONT AS SUPPORTING SHORTWAVE
ENERGY SHEARS NEWD. CURRENT TIMING PLACES THE FRONT OVER
NORTHWEST PA ON MONDAY WITH A SFC WAVE RIDING ALONG THE
FRONT...AND THE FRONT LIFTING NORTH OF THE STATE BY TUESDAY.

THIS SLOWER...LESS AGGRESSIVE SCENARIO WILL KEEP SCATTERED
SHOWERS/TSRA IN THE FORECAST FOR THE WEEKEND...BUT IS LESS
UNSETTLED FOR THE HOLIDAY WEEKEND THAN PREVIOUS THINKING. CLOUDY
CONDS ON MONDAY WILL BRING MAX TEMPS BACK TO WITHIN A COUPLE
DEGREES OF NORMAL AND BELOW NORMAL ON TUESDAY.

&&

.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
HIGH CLOUDS DRIFTING INTO NW MTNS ARE ASSOCIATED WITH A BAND OF
QUICKLY DIMINISHING CONVECTION /AT 02Z/ OVER NE OHIO. OTHERWISE
CLEAR SKIES WILL BE THE RULE FOR CENTRAL PA. LIGHT WINDS WILL
AGAIN LEAD TO FORMATION OF LIGHT FOG LATE...WITH LOCALIZED
IFR/LIFR DEVELOPING IN SOME VALLEYS IN FOG AND LOW CLOUDS...
WHICH WILL BURN OFF BY MID MORNING WED.

A COLD FRONT WILL CROSS THE LOWER GREAT LAKES LATE TONIGHT AND
MOVE SOUTH THRU THE AIRSPACE DURING THE DAYTIME HOURS ON WED.
MODELS INDICATING AN MVFR DECK POSS AT KBFD WED MORNING. SCT
SHOWERS AND THUNDERSTORMS WILL THEN DEVELOP ALONG/AHEAD OF THE
COLD FRONT...MAINLY IN CENTRAL AND SOUTHERN PA...WITH LOCAL
RESTRICTIONS EXPECTED WITH THE CONVECTION. DID NOT MENTION
RESTRICTIONS IN TAFS AT THIS TIME DUE TO EXPECTED SCATTERED
NATURE OF STORMS.

OUTLOOK...

THU-FRI...LATE NIGHT-EARLY MORNING RESTRICTIONS IN FOG
POSSIBLE...OTHERWISE VFR.

SAT-SUN...MAINLY VFR. CHC OF SHOWERS/ISOLD TSTMS.

&&

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

&&

$$
SYNOPSIS...LA CORTE
NEAR TERM...DEVOIR/LA CORTE
SHORT TERM...LA CORTE
LONG TERM...LAMBERT/GARTNER
AVIATION...RXR


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