222
FXUS61 KCTP 271911
AFDCTP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
311 PM EDT FRI JUN 27 2025
SYNOPSIS
* SEVERAL AREAS OF SLOW MOVING SHOWERS AND THUNDERSTORMS WITH
LOCALLY VERY HEAVY RAIN EXPECTED, MAINLY OVER THE WESTERN
MOUNTAINS AND LOWER SUSQUEHANNA VALLEY/SOUTHERN POCONOS THIS
AFTERNOON AND EVENING.
* MAX TEMPS WILL BE MUCH COOLER THAN WHAT OCCURRED THURSDAY.
* BREAKING HEAT GIVES WAY TO DRENCHING DOWNPOURS INTO THE LAST
WEEKEND OF JUNE; UNSETTLED PATTERN CONTINUES TO START JULY
NEAR TERM /UNTIL 8 PM THIS EVENING/
WIDESPREAD AND THICK STRATUS DECK WITHIN A COOL AIR DAMMING
REGIME UNDER LLVL EAST/SERLY FLOW OF MARINE AIR OFF THE WESTERN
ATLANTIC.
POOLING OF PWAT AND SLOW MOVING AREAS OF 925-850 MB THETA-E
CONVERGENCE AND ISENT UPGLIDE OVER THE LOWER SUSQ VALLEY AND
SOUTHERN POCONOS WILL CONTINUE TO BRING SOME ENHANCED WSW-ENE
BANDS OF HEAVY RAINFALL WITH HOURLY RATES OF 0.5-1.0 INCH,
POSSIBLY LEADING TO SOME MINOR FLOODING ISSUES LATE THIS
AFTERNOON/EVENING.
THE AREA OF MORE POTENTIALLY SERIOUS FLASH FLOOD THREAT WILL BE
OVER OUR WESTERN COUNTIES (SPECIFICALLY OVER CAMBRIA AND
SOMERSET COUNTIES NEAR THE NORTH/SOUTH LAUREL RIDGE - JUST WEST
OF RT 219).
HERE, A GOOD/CONTINUOUS INSTABILITY SOURCE REGION WILL CONTINUE
TO FEED THE GROWTH/NE DRIFT OF TSRA WITH VERY HEAVY RAINFALL
RATES OF 2-4 INCHES PER HOUR.
COLLABORATED WITH WFO PBZ AND LWX TO POST A FLOOD WATCH FOR
FLASH FLOODING FOR THE LAUREL HIGHLANDS THROUGH MIDNIGHT
TONIGHT. WILL ALSO HAVE TO KEEP A CLOSE EYE ON THE CONVECTIVE
AND HEAVY RAIN THREAT ACROSS THE NW MTNS WHERE A FEW BANDS OF
TSRA COULD EVENTUALLY CONVERGE TO RAMP UP THE FLASH FLOODING
THREAT AFTER 21Z.
ELSEWHERE ACROSS THE CENTRAL AND NE PART OF THE CWA, THE
WIDESPREAD CLOUDS, COOLER TEMPS AND LACK OF SIGNIFICANT FORCING
AT ANY LAYER WILL PRECLUDE A HEAVY RAIN THREAT.
TEMPS WILL ONLY RISE A FEW MORE DEGREES F OVER THE NEXT SEVERAL
HOURS AND TOP OUT MAINLY IN THE U60S TO L70S ACROSS THE BULK OF
THE REGION EAST OF THE RT 219 CORRIDOR. WEST OF RT 219, WHERE
SOME SUNSHINE WILL OCCUR AND THEY'LL BE OUT OF THE SHALLOW COLD
AIR WEDGE, HIGHS WILL REACH THE MID AND UPPER 70S.
SHORT TERM /8 PM THIS EVENING THROUGH SUNDAY NIGHT/
CONVECTIVE CORRIDOR ALONG THE WESTERN/SOUTHERN PERIPHERY OF THE
CWA FADES INTO TONIGHT WITH THE LOSS OF HEATING/INSTABILITY.
CAN'T RULE OUT A STRAY SHOWER OR TWO IN A FEW SPOTS OVERNIGHT,
BUT EXPECT THE MAJORITY OF THE TIME TO BE DRY. LOW STRATUS
CLOUDS WILL REMAIN ENTRENCHED DOWNWIND OF THE ALLEGHENY FRONT
WITH POCKETS OF RIDGETOP FOG/MIST/DRIZZLE. CLOUDY AND MUGGY
CONDITIONS EXPECTED HEADING INTO THE LAST WEEKEND OF JUNE WITH
LOWS IN THE 60-70F RANGE OR +5-10 DEGREES ABOVE CLIMO.
MODEL GUIDANCE SHOWS THE LOW CLOUDS GRADUALLY ERODING THROUGH
MIDDAY OVER THE CENTRAL RIDGES AND EASTERN VALLEYS. CLOUD BREAKS
SHOULD ALLOW FOR SUFFICIENT BL HEATING WITH SIGNIFICANT UPSIDE
TO SBCAPE VALUES >2000 J/KG WITH FCST MAX TEMPS 85-90F OVER
SOUTH CENTRAL PA. STORMS ARE EXPECTED TO FORM ALONG AND AHEAD OF
SOUTHEASTWARD ADVANCING COLD FRONT AND PRE FRONTAL/LEE SIDE SFC
TROUGH BY THE AFTERNOON. CAM GUIDANCE IS SHOWING SOME MIXED
SIGNALS CONCERNING THE EXTENT OF CONVECTIVE POTENTIAL AND DEEP
LAYER SHEAR IS <30KT. THAT SAID, THE STRONG SFC EATING AND
STEEP LOW LEVEL LAPSE RATES MAY BE ENOUGH TO SUPPORT A LOCALIZED
DAMAGING WIND THREAT DURING THE AFTERNOON AND EVENING. SPC HELD
THE D2 RISK LEVEL AT 1 OUT OF 5 (MRGL) WITH THE 1730UTC UPDATE.
SFC HIGH PRESSURE BUILDING INTO CPA BEHIND THE FRONT PROVIDES A
DRY PERIOD SATURDAY NIGHT THROUGH SUNDAY. ANY CLEARING SATURDAY
NIGHT COULD RESULT IN A FOGGY START TO THE LAST SUNDAY IN JUNE.
LONG TERM /MONDAY THROUGH THURSDAY/
STORMY PATTERN RESUMES EARLY NEXT WEEK WITH A SHORTWAVE TROUGH
PROGRESSING THROUGH THE GREAT LAKES SENDING A QSTNRY/WARM AND
COLD FRONT THROUGH THE REGION MONDAY AND TUESDAY. FOR NOW, THE
SIGNAL IS RELATIVELY WEAK FOR RAINFALL LEADING UP TO THE 4TH OF
JULY. HOWEVER, ANOTHER NORTHERN STREAM FRONT WILL KEEP LOW POPS
IN THE FORECAST FOR INDEPENDENCE DAY.
AVIATION /19Z FRIDAY THROUGH WEDNESDAY/
WIDESPREAD LOW STRATUS CIGS (800-1500 FT AGL) WILL PERSIST INTO
THIS EVENING BEFORE LOWERING A FEW TO SEVERAL HUNDRED FEET
TONIGHT - INTO THE LIFR RANGE. VSBYS WILL STAY MVFR OR BETTER
FOR MOST OR ALL OF THE TAF PERIOD AT ALL AIRFIELDS.
CONDITIONS WILL IMPROVE THROUGH IFR/MVFR DURING THE MID TO LATE
MORNING HOURS BEFORE REACHING VFR AT MOST OR ALL AIRFIELDS BY
14-15Z SATURDAY.
ANOTHER ROUND OF SHRA/GUSTY TSRA SHOULD MOVE SE ACROSS MUCH OR
ALL OF PA SAT AFTERNOON AND EVENING ALONG AND AHEAD OF A COLD
FRONT.
OUTLOOK...
SAT-TUE...SHOWERS AND T-STORMS WITH TIMES OF FOG AND LOW CLOUDS
OVERNIGHT. SUNDAY LOOKING LIKE THE BEST DAY TO STAY DRY.
CTP WATCHES/WARNINGS/ADVISORIES
FLOOD WATCH UNTIL MIDNIGHT EDT TONIGHT FOR PAZ024-033.
SYNOPSIS...LAMBERT/BOWEN
NEAR TERM...LAMBERT/TYBURSKI
SHORT TERM...STEINBUGL
LONG TERM...STEINBUGL
AVIATION...LAMBERT/MARTIN
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