339
FXUS61 KCTP 172333
AFDCTP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
733 PM EDT WED SEP 17 2025
SYNOPSIS
* SEVERAL BANDS OF LIGHT TO MODERATE RAIN/SHOWERS PUSHING WEST
ACROSS THE SUSQUEHANNA VALLEY AND SOUTH-CENTRAL MOUNTAINS OF
PA TODAY AND TONIGHT, WITH THE COOLEST HIGH TEMPERATURES OF
THE WEEK OCCURRING TODAY.
* RAINFALL AMOUNTS GENERALLY BETWEEN ONE TENTH AND ONE QUARTER
OF AN INCH. LOCALLY OVER ONE HALF OF AN INCH ACROSS PORTIONS
OF THE LOWER SUSQUEHANNA VALLEY.
* DRY CONDITIONS RETURN AREAWIDE ON THURSDAY AND WILL PERSIST
THROUGH THE WEEKEND WITH TEMPERATURES REBOUNDING TO WELL-ABOVE
NORMAL.
NEAR TERM /UNTIL 6 AM THURSDAY MORNING/
A PERSISTENT DEEP EASTERLY FLOW WILL SUPPORT SEVERAL BANDS OF
LIGHT TO BRIEFLY MDT/HVY SHOWERS WESTWARD OVER THE SE 1/3 OF OF
CWA LATE THIS AFTERNOON AND INTO EARLY TONIGHT.
NEAR, AND JUST TO THE SE OF THE I-99/RT 220, A FEW LIGHTER RAIN
SHOWERS WILL LIKELY OCCUR, BUT WON'T AMOUNTS TO MORE THAN A
FEW/SVRL HUNDREDTHS OF AN INCH IN MOST PLACES.
THE GENERALLY THICK CLOUD COVER ACROSS THE SE TWO THIRDS OF THE
CWA, PERSISTENT EASTERLY FLOW WILL KEEP TEMPERATURES
SIGNIFICANTLY COOLER THAN RECENT DAYS.
FOR TONIGHT, THE AFOREMENTIONED COASTAL LOW WILL MOVE OFF THE NJ
COAST AND THE SINGLE, CLOSED-CONTOUR UPPER LEVEL LOW WILL
TRANSITION TO A POSITIVE-TILT. OPEN WAVE CAUSING THE LOW TO MID
LEVEL FLOW TO BACK THROUGH THE NE THEN NORTH BY MORNING. THIS
WILL LEAD TO A SIGNIFICANT DECREASE IN POPS AND AREAL COVERAGE
FOR SHOWERS BY OR SHORTLY AFTER MIDNIGHT TONIGHT.
SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY/
THURSDAY AND FRIDAY WILL BE A CONTINUATION OF WHAT WE'VE SEEN
FOR A MAJORITY OF THE PAST COUPLE WEEKS WITH PLENTY OF SUNSHINE,
SEASONABLY MILD TEMPERATURES, AND LIGHT WINDS. IT WILL TAKE A
LITTLE WHILE FOR THE MOISTURE IN SOUTHEAST PA TO BE REPLACED BY
A DRIER AIRMASS, SO EXPECT THE AIR TO FEEL A BIT HUMID STILL ON
THURSDAY. HIGHS WILL GENERALLY BE IN THE 80S WITH LOWS IN THE
UPPER 40S (NW) TO LOWER 60S (SE). A BACKDOOR, MOISTURE-DEPRIVED
COLD FRONT WILL SAG SOUTH INTO NORTHERN PENNSYLVANIA FRIDAY
AFTERNOON, WITH AN INCREASE IN CLOUD COVER NORTH OF US-6 BEING
THE ONLY NOTEWORTHY ASPECT OF ITS ARRIVAL. DRIER AIR AWAITS IN
ITS WAKE...
LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/
FRIDAY NIGHT - THE AFOREMENTIONED BACKDOOR COLD FRONT WILL
SLIDE THROUGH PENNSYLVANIA WITH A STRONG 1028MB HIGH SURGING IN
BEHIND IT. DEWPOINTS WILL PLUMMET BY SATURDAY MORNING,
SUPPORTING A RETURN TO BELOW-NORMAL OVERNIGHT TEMPERATURES WITH
CLEAR SKIES AND CALM WINDS. SURFACE HIGH PRESSURE WILL SET UP
OFF THE NEW ENGLAND COAST FOR THE WEEKEND, ENSURING MOIST
SOUTHEAST FLOW AND TRANQUIL WEATHER. HIGHS WILL TICK DOWN A FEW
DEGREES FOR THE WEEKEND, WITH HIGHS IN THE 70S AND LOWS IN THE
50S MOST LIKELY AT THIS TIME.
HEADING INTO NEXT WEEK, HIGH PRESSURE WILL BEGIN TO LOSE ITS
GRIP ON THE REGION AS AN UPPER TROUGH TRIES TO DISRUPT THE
PERSISTENT RIDGE OF HIGH PRESSURE ALOFT. STILL PLENTY OF
UNCERTAINTY ON HOW MUCH, IF ANY, PRECIPITATION WILL GET INTO
PENNSYLVANIA BUT SOUTHERLY FLOW AHEAD OF THE APPROACHING SYSTEM
WILL SUPPORT CONTINUED WARMER THAN AVERAGE TEMPERATURES FOR THE
START OF ASTRONOMICAL FALL.
AVIATION /00Z THURSDAY THROUGH MONDAY/
SCATTERED SHOWERS ACROSS EASTERN PENNSYLVANIA WILL GRADUALLY
FADE OVER THE NEXT COUPLE OF HOURS WITH NO IMPACTS OUTSIDE OF A
SPRINKLE EXPECTED AT LNS. CONFIDENCE IN -SHRA AT LNS REMAINS TOO
LOW TO INCLUDE IN THE 00Z TAF PACKAGE BASED ON CURRENT RADAR
TRENDS/RECENT MODEL GUIDANCE DUE TO THE SCATTERED NATURE OF
REMAINING SHOWERS.
SLIGHTLY MORE CLOUD COVER THIS EVENING COULD LIMIT EARLIER FOG
PROJECTIONS, WITH RECENT RAP/GLAMP GUIDANCE SCALING BACK ON FOG
MENTIONS OVERNIGHT. THE WESTERN TERMINALS (BFD/JST/AOO) WILL
HAVE THE HIGHEST CHANCES OF CLEAR CONDITIONS OVERNIGHT, WHICH
WILL ALLOW FOR SOME FORMATIONS; HOWEVER, THIS LOOKS MORE LIMITED
TO VALLEY LOCATIONS AT THIS TIME. HAVE PROGGED IFR/LIFR
RESTRICTIONS AT AOO BASED ON RECENT GLAMP/HREF PROBABILITIES
WITH MODERATE (50-60%) CONFIDENCE; HOWEVER, LOWER CONFIDENCE
(20-30%) AT BFD/JST IN FOG REACHING INTO THE AIRFIELD BETWEEN
07-11Z THURSDAY. WHILE MODEL GUIDANCE DOES OUTLINE LOWER CHANCES
FOR IPT/MDT/LNS CLEARING OUT, INCREASED LOW- LEVEL MOISTURE
COUPLED WITH EASTERLY FLOW WILL RETAIN SOME THREAT FOR FOG/LOW
STRATUS POTENTIAL; HOWEVER, LOW CONFIDENCE IN THIS OCCURRING AS
OF THE 00Z TAF PACKAGE.
COASTAL LOW CONTINUES DRIFTING EAST OF THE AREA WITH WIDESPREAD
CLEARING EXPECTED AFTER 12Z THURSDAY. ANY FOG/LOW STRATUS
DEVELOPMENT COULD LINGER THROUGH UNTIL ~14Z THURSDAY; HOWEVER,
LOWER CONFIDENCE IN WHERE THIS FOG WILL DEVELOP AS OF 00Z
THURSDAY. WIDESPREAD VFR CONDITIONS ARE PROGGED BY ALL MODEL
GUIDANCE AFTER 14Z/15Z THROUGH THE END OF THE TAF PERIOD.
OUTLOOK...
FRI-SUN...VFR WITH AM VALLEY FOG.
MON...SLIGHT CHANCE SHRA/PM TSRA POSSIBLE ACROSS NW PA.
CLIMATE
ASTRONOMICAL FALL OFFICIALLY BEGINS WITH THE AUTUMNAL EQUINOX
ON MONDAY, SEPTEMBER 22, 2025 @ 2:19 P.M. EDT. THE AUTUMN 2025
SEASON WILL LAST 89 DAYS, 20 HOURS, AND 43 MINUTES. DAYLIGHT
SAVING TIME WILL END JUST AFTER HALLOWEEN WITH CLOCKS FALLING
BACK AT 2 A.M. SUNDAY, NOVEMBER 2, 2025.
CTP WATCHES/WARNINGS/ADVISORIES
NONE.
SYNOPSIS...LAMBERT/GARTNER
NEAR TERM...LAMBERT/GARTNER
SHORT TERM...LAMBERT/GARTNER
LONG TERM...LAMBERT/BANGHOFF
AVIATION...NPB
CLIMATE...STEINBUGL
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