676
FXUS61 KCTP 300917
AFDCTP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
517 AM EDT WED SEP 30 2026
WHAT HAS CHANGED
* DENSE FOG ADVISORY ISSUED FOR THE NW ALLEGHENIES UNTIL 9AM
* ODDS FOR RAIN INCREASED TONIGHT (NORTHERN TIER) AND FRIDAY
* ODDS FOR RAIN DECREASED/SHIFTED TO THE SOUTH FOR THE WEEKEND
* INCREASING CONFIDENCE IN FROST/FREEZE RISK EARLY NEXT WEEK
KEY MESSAGES
1) QUICK TURNAROUND TO SUMMERLIKE WARMTH TO END SEPTEMBER AND
START OCTOBER
2) SHOWERS EXPECTED FRIDAY WITH COOLER WEEKEND FORECAST
TRENDING DRIER
3) INCREASING CONFIDENCE IN FROST/FREEZE RISK EARLY NEXT WEEK
DISCUSSION
KEY MESSAGE 1: QUICK TURNAROUND TO SUMMERLIKE WARMTH TO END
SEPTEMBER AND START OCTOBER
A BURST OF SUMMERLIKE CONDITIONS ARE EXPECTED TO PEAK LATER THIS
WEEK AS THE CALENDER FLIPS FROM SEPTEMBER TO OCTOBER. FCST MAX
TEMPS ON THU/FRI IN THE 75-85F RANGE ARE +10-15 DEGREES ABOVE
THE HISTORICAL AVERAGE AND MAY BE THE WARMEST CONDITIONS
OBSERVED FOR THE REMAINDER OF 2026. FOR CONTEXT, THE AVERAGE
LAST DATE OF MAX TEMP >=80F IS 9/27 AT STATE COLLEGE, 9/29 AT
ALTOONA, 10/2 AT WILLIAMSPORT AND 10/5 AT HARRISBURG.
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KEY MESSAGE 2: SHOWERS EXPECTED FRIDAY WITH COOLER WEEKEND
FORECAST TRENDING DRIER
SOME LIGHT RAIN COULD BRUSH THE NORTHERN TIER LATER TONIGHT INTO
EARLY THURSDAY MORNING. THE BEST ODDS FOR MORE WIDESPREAD RAIN
SHOWERS ARE NOW FOCUSED ON THE LATE THURSDAY NIGHT (NW) THROUGH
FRIDAY TIME WINDOW AS A COLD FRONT MOVES SOUTHEASTWARD FROM THE
EASTERN GREAT LAKES. LATEST MODEL DATA NOW IN BETTER AGREEMENT
IN SUPPRESSING RAIN CHANCES FARTHER TO THE SOUTH THIS WEEKEND
RESULTING IN DECLINING PRECIP PROBS/INCREASING ODDS FOR A
MAINLY DRY FIRST WEEKEND OF OCTOBER.
NOTICEABLY COOLER AND LESS HUMID AIR WILL FILTER INTO THE
REGION BEHIND THE FRONT. 24HR MAXT CHANGE ON SATURDAY IS FCST TO
BE 10-15 DEGREES LOWER VS. FRIDAY ACROSS SOUTH CENTRAL PA WITH
HIGHS IN THE 60-70F RANGE. THE COOLING TREND CONTINUES THROUGH
EARLY NEXT WEEK WITH NO RAIN FORECAST THROUGH WEDNESDAY.
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KEY MESSAGE 3: INCREASING CONFIDENCE IN FROST/FREEZE RISK EARLY
NEXT WEEK
SECONDARY SHOT OF SEASONABLY COOL/AUTUMN AIR IS FCST TO ARRIVE
EARLY NEXT WEEK IN ASSOCIATION WITH CANADIAN HIGH PRESSURE. THE
OVERALL PATTERN AND CORRESPONDING NBM TEMPERATURES ARE SIGNALING
AN INCREASED RISK OF FROST/FREEZE CONDITIONS MONDAY AND TUESDAY
NIGHT. SOME LOCATIONS IN THE CENTRAL ALLEGHENIES MAY OBSERVE
THE FIRST FROST/FREEZE OF THE SEASON WHICH IS GENERALLY ON PAR
WITH CLIMO.
AVIATION /09Z WEDNESDAY THROUGH SUNDAY/
RECENT SATELLITE IMAGERY SHOWS THAT THE STUBBORN STRATUS DECK
OVER CENTRAL PA IS BEGINNING TO ERODE FROM WEST TO EAST. VALLEY
FOG IS QUICKLY FORMING IN AREAS THAT HAVE CLEARED OUT AND THE
EXPECTATION IS THAT THE FOG WILL EXPAND EASTWARD AS CLOUDS
CONTINUE TO CLEAR. BFD, AOO, AND UNV APPEAR MOST LIKELY TO SEE
IFR CONDITIONS IN FOG, THOUGH THERE COULD BE A BRIEF WINDOW OF
OPPORTUNITY CLOSER TO SUNRISE FOR FOG TO FORM AT IPT IF THE
CLOUDS CLEAR OUT FAST ENOUGH.
THE FOG WILL BURN OFF BY 14Z, GIVING WAY TO VFR CONDITIONS FOR
THE REST OF THE DAY WITH INCREASING HIGH CLOUDS AND LIGHT
SOUTHERLY WINDS. MODERATE WARM ADVECTION ASSOCIATED WITH A
SHORTWAVE TRACKING TO OUR NORTH INTO THURSDAY MORNING WILL
SUPPORT LIGHT RAIN DEVELOPING OVER THE NORTHERN HALF OF THE
REGION AFTER 00Z THURSDAY. AS OF NOW, IT APPEARS THAT RAIN COULD
MAKE IT AS FAR SOUTH AS UNV. THE RAIN SHOULD BE PRETTY LIGHT AND
CLOUD BASES DON'T LOOK TO GET BELOW 5000 FEET, SO EXPECT VFR
CONDITIONS TO CONTINUE.
OUTLOOK...
THU...-SHRA POSSIBLE, MAINLY OVER NORTHERN PA, WITH POTENTIAL
FOR LOCALIZED AM MIST/FOG.
THU NIGHT - FRI...COLD FROPA WITH SHOWERS ALONG THE FRONT. LLWS
POSSIBLE, ESPECIALLY NORTHERN AND WESTERN TAF SITES.
SAT-SUN...VFR FAVORED BEHIND THE FROPA, WITH LOWER CONFIDENCE
ACROSS SOUTHERN PA WHERE LINGERING MOISTURE MAY BRING INTERVALS
OF LOW CEILINGS (PRIMARILY MVFR). AM FOG POSSIBLE.
CLIMATE
SOGGY SEPTEMBER SOAKER...
SEPTEMBER 2026 (MTD) PRECIPITATION RANKINGS
IPT: 11TH WETTEST (6.84")
MDT: 26TH WETTEST (4.72")
AOO: 9TH WETTEST (5.58")
BFD: 10TH WETTEST (4.85")
JST: 3RD WETTEST (7.31") *SINCE 2000
STC: 6TH WETTEST (7.90")
CTP WATCHES/WARNINGS/ADVISORIES
DENSE FOG ADVISORY UNTIL 9 AM EDT THIS MORNING FOR PAZ004>006-
010-011-017.
WHAT HAS CHANGED...STEINBUGL
KEY MESSAGES...STEINBUGL
DISCUSSION...STEINBUGL
AVIATION...BAUCO
CLIMATE...STEINBUGL
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