913
FXUS61 KCTP 170639
AFDCTP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
239 AM EDT SUN MAY 17 2026
WHAT HAS CHANGED
* WESTERN EDGE OF THE SHOWERS PUSHING EAST OF OUR AREA.
* NUDGED HIGH TEMPERATURES DOWN SUNDAY-TUESDAY TO ACCOUNT FOR
KNOWN BIASES IN THE NBM FORECAST IN PATTERNS LIKE THIS.
KEY MESSAGES
1) SHOWERS WITH GUSTY WINDS HAVE ENDED.
2) HOTTEST TEMPERATURES OF THE YEAR SO FAR FORECAST EARLY NEXT
WEEK WITH HIGHS PUSHING INTO THE 80S AND 90S.
3) STRONG COLD FRONT TO BRING SHOWERS AND STORMS WITH POTENTIAL
FOR SEVERE WEATHER ON WEDNESDAY FOLLOWED BY COLDER TEMPERATURES.
DISCUSSION
KEY MESSAGE 1: SHOWERS WITH GUSTY WINDS HAVE ENDED.
THE COMBINATION OF FAST MOVING SHOWERS AND DRY AIR AT LOW
LEVELS RESULTED IN SOME GUSTY WINDS EARLIER BUT THEY SHOWERS
HAVE MOVED OUT OF MOST OF THE AREA AS OF MID EVENING.
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KEY MESSAGE 2: HOTTEST TEMPERATURES OF THE YEAR SO FAR FORECAST
EARLY NEXT WEEK WITH HIGHS PUSHING INTO THE 80S AND 90S.
DAYTIME HIGH TEMPERATURES WILL BE STEADILY RISING TODAY THROUGH
EARLY IN THE UPCOMING WEEK. AN ANOMALOUS UPPER RIDGE BUILDING
OVER THE EAST-CENTRAL U.S. WILL DELIVER SUMMERLIKE CONDITIONS
THIS WEEKEND THROUGH THE FIRST PART OF THE NEW WEEK. HIGH
TEMPERATURES WILL PEAK IN THE MID 80S TO LOWER 90S MONDAY AND
TUESDAY AND COULD CHALLENGE DAILY RECORDS IN SOME LOCATIONS.
MANUAL ADJUSTMENTS WERE MADE TO LOWER NBM MAXT BY A FEW DEGREES
DUE TO A KNOWN SYSTEMATIC BIAS CORRECTION ISSUE IDENTIFIED
DURING THE SHOULDER SEASONS. THIS SHOULD ALSO KEEP MAX HEAT
INDICES UNDER 100F FOR THE MOST PART. HOWEVER, HEAT RISK IMPACTS
WILL CONTINUE TO BE MONITORED GIVEN THE QUICK RAMP- UP IN HEAT
AND LIMITED ACCLIMATION TIME. DEWPOINTS OVER 60S FOR MANY WILL
ALSO FEEL QUITE HUMID RELATIVE THE RECENT COOL STRETCH WE'VE
HAD.
WITH A BOUNDARY JUST TO OUR NORTH AND SUFFICIENT INSTABILITY IN
THE WARM SECTOR OVER PA, THERE WILL BE A CHANCE FOR SOME STRAY
AFTERNOON AND EARLY EVENING SHOWERS OR THUNDERSTORMS MONDAY AND
TUESDAY. MOST FOLKS SHOULD STAY DRY, BUT THUNDERSTORMS COULD
DROP A QUICK 0.10 TO 0.25" OF RAIN IN ANY ONE LOCATION.
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KEY MESSAGE 3: STRONG COLD FRONT TO BRING SHOWERS AND STORMS WITH
POTENTIAL FOR SEVERE WEATHER ON WEDNESDAY FOLLOWED BY COLDER
TEMPERATURES.
A COLD FRONT (ACCOMPANIED BY MORE WIDESPREAD AND FREQUENT
SHOWERS/T-STORMS) BRINGS RELIEF NEXT WEDNESDAY INTO THURSDAY.
SOME OF THE AI GUIDANCE PAINTS AN ELEVATED RISK OF SEVERE
WEATHER ACROSS THE LOWER SUSQUEHANNA VALLEY ON WEDNESDAY
AFTERNOON IN THE PRESENCE OF PEAK HEATING AND SUFFICIENT
SHEAR/CAPE PROFILES. THE MAGNITUDE & LOCATION OF THE SEVERE
THREAT WILL BE HIGHLY DEPENDENT ON COLD FRONT PASSAGE TIMING.
THE EVENTUAL RISK AREA WILL HIGHLIGHT LOCATIONS ALONG AND
DOWNSTREAM OF THE COLD FRONT BETWEEN 12PM AND 8PM ON WEDNESDAY.
IN THE WAKE OF THE COLD FRONT, HIGH PRESSURE WILL BUILD IN FOR
A SHORT TIME. TEMPERATURES ARE FORECAST TO COOL DOWN BACK TO
HISTORICAL/CLIMO AVERAGES FOR LATE MAY FOR THE END OF NEXT WEEK.
EARLY INDICATIONS SHOW THE AFOREMENTIONED COLD FRONT STALLING
OUT SOUTH OF THE MASON-DIXON LINE LATE IN THE WEEK AND LIFTING
BACK NORTH ACROSS PA AS A WARM FRONT INTO MEMORIAL DAY WEEKEND.
THE CURRENT OUTLOOK FAVORS A COOLER/WETTER STRETCH THROUGH THE
HOLIDAY WEEKEND THANKS TO THAT WARM FRONT, BUT THERE IS STILL A
LOT OF TIME FOR THE FORECAST TO TREND IN A MORE FAVORABLE/OPTIMISTIC
DIRECTION FOR THE HOLIDAY WEEKEND THAT MARKS THE UNOFFICIAL START
OF SUMMER.
AVIATION /06Z SUNDAY THROUGH THURSDAY/
LOW-LEVEL MOISTURE FROM YESTERDAY'S SHOWERS + UPSLOPE
SOUTHWESTERLY FLOW WILL CONTRIBUTE TO IFR/LIFR RESTRICTIONS
ACROSS PORTIONS OF THE NORTHERN TIER (KBFD), WITH INTERMITTENT
MVFR/VFR ACROSS THE CENTRAL MOUNTAINS (KJST/KAOO/KUNV). PATCHY
FOG MAY DEVELOP OVERNIGHT GIVEN ANTECEDENT MOISTURE & POCKETS OF
CLEAR SKIES, THOUGH NO FOG MENTIONS WERE ADDED IN THE TAF
OUTSIDE FROM KBFD. AFTER DAYBREAK, BOUNDARY LAYER MIXING WILL
RAISE CEILINGS AND SCATTER THE LOW CLOUD DECK, WITH REGIONWIDE
VFR EXPECTED BY THE AFTERNOON.
VFR WILL PREVAIL ON SUNDAY AS A RIDGE CONTINUES TO BUILD ALONG
THE EAST COAST ON SUNDAY. WITH THAT SAID, WEAK SHORTWAVES
EMBEDDED WITHIN THE NORTHERN PERIPHERY OF THIS RIDGE MAY
INITIATE SPOTTY CONVECTION. INSTABILITY WILL GROW SUPPORTIVE OF
CONVECTION AS THE DAY PROGRESSES, WITH HREF MEAN SBCAPE AROUND
1000 J/KG & NEGLIGIBLE CIN IN PLACE, THOUGH SYNOPTIC-SCALE
SUPPRESSION WILL TEMPER ACTIVITY OVERALL. COVERAGE AND TIMING
OF CONVECTION IS INCONSISTENT ACROSS CAMS GIVEN THE NEBULOUS
FORCING, WITH SHOWER/THUNDERSTORM COVERAGE EXPECTED TO BE BELOW
30% ACROSS THE REGION. ANY CELLS THAT DO DEVELOP WILL DISSIPATE
DURING THE EVENING AS DAYLIGHT ENDS AND RIDGING BECOMES FURTHER
ENTRENCHED ACROSS THE EAST COAST.
PATCHY FOG WILL BE POSSIBLE ONCE AGAIN SUNDAY NIGHT (MAINLY AFTER
06Z MONDAY) GIVEN LIGHT/VARIABLE WINDS, MAINLY CLEAR SKIES, AND
SURFACE DEW POINTS AROUND 60 DEGREES.
OUTLOOK...
MON-TUE...MAINLY VFR. PATCHY A.M. FOG. ISOLATED P.M. SHOWER OR
T-STORM POSSIBLE.
WED...RESTRICTIONS PROBABLE THROUGH WEDNESDAY NIGHT WITH
WIDESPREAD SHOWERS/STORMS ALONG CFROPA.
THU...LINGERING SHOWERS ACROSS S PA, RESTRICTIONS POSSIBLE.
CLIMATE
DAILY RECORD MAX TEMPERATURE FOR MAY 18-19:
5/18 5/19
HARRISBURG 94 IN 1962 95 IN 1962
WILLIAMSPORT 95 IN 1962 96 IN 1996
ALTOONA 91 IN 1962/1996/2017 92 IN 1996
BRADFORD 85 IN 1962 85 IN 1962
STATE COLLEGE 92 IN 1962 92 IN 1934/1996
PLEASE NOTE: STATE COLLEGE CO-OPERATIVE OBSERVATIONS ARE A
24-HOUR SUMMARY TAKEN ONCE PER DAY AROUND 7 AM (7AM-7AM).
THEREFORE, A MAX TEMP OCCURRING IN THE DAYLIGHT OR LATE IN THE
DAY IS USUALLY REPORTED IN THE _NEXT_ DAY'S OBSERVATION. ALSO,
THE SAME MIN TEMP MAY BE REPORTED ON TWO CONSECUTIVE DAYS IF THE
MIN OCCURS AT OBSERVATION TIME.
CTP WATCHES/WARNINGS/ADVISORIES
NONE.
WHAT HAS CHANGED...BANGHOFF/MARTIN
KEY MESSAGES...LAMBERT/BANGHOFF/MARTIN
DISCUSSION...LAMBERT/BANGHOFF/MARTIN
AVIATION...TEARE
CLIMATE...DANGELO/STEINBUGL
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