562
FXUS61 KCTP 200143
AFDCTP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
943 PM EDT TUE MAY 19 2026
WHAT HAS CHANGED
* LITTLE THREAT FOR WIND GUSTS OVER 40 KTS EARLY TONIGHT ACROSS
NW PA WITH THE LINE OF SHRA/TSRA WELL IN ADVANCE OF A COLD
FRONT.
* INCREASING ODDS FOR A NOTICEABLY COOLER AND RATHER WET START
TO MEMORIAL DAY WEEKEND (LOWERED MAX TEMPS FOR SAT BY SEVERAL
DEG F WITH EXTENSIVE LOW CLOUDS, LLVL EASTERLY FLOW AND
PERIODS OF RAIN/DRIZZLE/RIDGE SHROUDING FOG.
KEY MESSAGES
1) SCATTERED STRONG THUNDERSTORMS ARE POSSIBLE ACROSS THE NW
MTNS EARLY TONIGHT, THEN ACROSS SOUTH CENTRAL PA AND THE LOWER
SUSQ VALLEY WEDNESDAY AFTERNOON
2) MAJOR COOLDOWN ARRIVES THURSDAY AND LASTS INTO MEMORIAL DAY
WEEKEND WITH WIDESPREAD SOAKING RAINFALL (OVER 1 INCH) LIKELY
FRIDAY AND SATURDAY
DISCUSSION
KEY MESSAGE 1: SCATTERED STRONG THUNDERSTORMS ARE POSSIBLE ACROSS
THE NW MTNS EARLY TONIGHT, THEN ACROSS SOUTH CENTRAL PA AND THE
LOWER SUSQ VALLEY WEDNESDAY AFTERNOON
SPC TRIMMED BACK ITS SLGT RISK AREA FOR SVR OUT OF NW PA WITH
ITS 0045Z UPDATE.
A WEAKENING LINE OF SHOWERS AND THUNDERSTORMS WILL BE MOVING
ACROSS OUR NW MTN ZONES BETWEEN 02-05Z WITH SOME WIND GUSTS OF
35-40 KTS POSSIBLE, MORE SO ACROSS THE REGION SOUTH OF ROUTE 6
WHERE THE BEST COMBINATION OF SFC BASED CAPE OVER 1000 J/KG AND
DCAPE OF ~1000 J/KG WILL EXIST.
ELSEWHERE ACROSS CENTRAL PA AND THE SUSQ VALLEY, EXPECT A PARTLY
TO MOSTLY CLOUDY AND RATHER MUGGY NIGHT WITH SFC TDS IN THE LOW
TO MID 60S IN MOST PLACES. MORE COMFORTABLE CONDITIONS WILL
OCCUR ACROSS THE NW MTNS WHERE RAIN-COOLED AIR AND SFC DEWPOINTS
ONLY AROUND 60F WILL BE FOUND.
DUAL TO MULTI-LAYERED CLOUDS WITH JUST SOME WIDELY SCATTERED
LIGHT SHOWERS WEDNESDAY MORNING WILL BE FOLLOWED BY A FEW
PERIODS OF SHOWERS IN THE EARLY-MID AFTERNOON, NEAR AND TO THE
NORTH OF I-80.
CONVECTIVE FOCUS SHIFTS TO SOUTH CENTRAL PA WEDNESDAY AFTERNOON
WITH NARROW PLUME OF WEAK TO MODERATE CAPE FCST AHEAD OF THE
AFOREMENTIONED COLD FRONT. STEEP LOW LEVEL LAPSE RATES MAY
SUPPORT A FEW INSTANCES OF STRONG TO SEVERE WINDS. THE MAGNITUDE
& LOCATION OF THE SEVERE THREAT WILL BE HIGHLY DEPENDENT ON
CFROPA TIMING AND AMOUNT OF CLOUD COVER. SPC MRGL RISK (LEVEL
1/5) COVERS THE SOUTHEAST HALF OF THE CWA WHERE MAX TEMPS ARE
FCST BTWN 80-90F.
-----------------------------------------------------------------
KEY MESSAGE 2: MAJOR COOLDOWN ARRIVES THURSDAY AND LASTS INTO
MEMORIAL DAY WEEKEND WITH WIDESPREAD SOAKING RAINFALL LIKELY
FRIDAY AND SATURDAY
RELIEF FROM THE EARLY SEASON HEAT WAVE ARRIVES IN EARNEST ON
THURSDAY WITH MAX TEMPS 20-30 DEGREES LOWER VS. WEDNESDAY ACROSS
THE SOUTHEAST HALF OF THE FORECAST AREA. STRONG HIGH PRESSURE
SLIDES FROM THE LOWER GREAT LAKES TO OFF THE NEW ENGLAND COAST
TO CLOSE OUT THE WEEK. MODEL DATA SHOWS THE HIGH CHANNELING
SOUTHWARD DOWN THE EAST-SIDE OF THE APPALACHIANS, SETTING UP A
COLD AIR DAMMING TYPE EVENT HEADING INTO MEMORIAL DAY WEEKEND.
EARLIER SHIFTS NOTED, "WE MAY NOT BE BEARISH ENOUGH ON DAYTIME
TEMPERATURES." DID TRIM MAX TEMPS SATURDAY DOWN BY 4-5 DEG F
GIVEN THE THICK CLOUDS, MODERATELY STRONG EAST-SERLY LLVL FLOW
AND PERIODS OF SOAKING RAIN THAT WILL DAMPEN AT LEAST THE START
OF THE HOLIDAY WEEKEND. WPC 48HR QPF AMOUNTS ARE QUITE WET WITH
A WIDESPREAD 1-2.5 INCHES FCST FROM 12Z FRIDAY TO 12Z SUNDAY.
AVIATION /01Z WEDNESDAY THROUGH SUNDAY/
WIDESPREAD VFR CONDITIONS PREVAIL AS OF 01Z WEDNESDAY, WITH
THESE CONDITIONS LIKELY (80-90% CONFIDENCE) TO CONTINUE AT ALL
AIRFIELDS OUTSIDE OF BFD THROUGH ~12Z WEDNESDAY. IN THIS
TIMEFRAME, APPROACHING A LINE OF SHRA WITH EMBEDDED TSRA WILL
APPROACH NW PA CLOSER TO THE ~03/04Z TIMEFRAME. THIS WILL LIKELY
BRING LOW-END VFR TO HIGH-END MVFR CEILINGS WHICH WILL PERSIST
THROUGHOUT THE ENTIRE OVERNIGHT PERIOD AND THROUGHOUT MUCH OF
THE EVENING HOURS ON WEDNESDAY (~22/23Z WEDNESDAY). CLOSER TO
THE 12Z TIMEFRAME, INCREASING SIGNALS FOR IFR AT BFD BASED ON A
CONSENSUS OF HREF ENSEMBLE MEMBERS AND MULTIPLE CYCLES OF GLAMP
MODEL GUIDANCE, SO HAVE DECIDED TO INCLUDE THESE IN THE TAFS
WITH MODERATE (~40-50%) CONFIDENCE ON TIMING. A BRIEF PERIOD OF
LOWER CEILINGS TRENDING TOWARDS LIFR WILL BE POSSIBLE; HOWEVER,
CONFIDENCE REMAINS TOO LOW FOR INCLUSION IN THE 00Z TAFS.
ELSEWHERE, THE AFOREMENTIONED LINE OF SHRA/TSRA IS EXPECTED TO
DIMINISH IN INTENSITY/COVERAGE OVERNIGHT, LEADING MANY AIRFIELDS
UNLIKELY TO RECEIVE ANY SHRA IN THE 00Z-12Z WEDNESDAY
TIMEFRAME. RECENT HREF RUNS HAVE BEEN FAIRLY CONSISTENT WITH THE
PROGRESSION OF A LOW-LEVEL CLOUD DECK ACROSS ALL OF CENTRAL
PENNSYLVANIA, SO HAVE INCLUDED THESE MENTIONS AND SLIGHTLY
ADJUSTED TIMING BASED ON RECENT HREF/NBM/GLAMP MODEL GUIDANCE IN
ORDER TO OUTLINE INITIAL ONSET OF MVFR RESTRICTIONS. THERE IS
HIGH (~70-80%) CONFIDENCE ON SHRA/TSRA REFORMING DURING THE LATE
MORNING TO EARLY AFTERNOON HOURS (MAINLY AFTER 16Z) WITH
INCREASING COVERAGE INTO THE EVENING HOURS. CURRENT SHRA
MENTIONS HAVE BEEN INCLUDED AT ALL TERMINALS ACROSS CENTRAL
PENNSYLVANIA BASED ON RECENT FORECAST/HREF/GLAMP MODEL GUIDANCE
WITH MOST UNCERTAINTY WITH RESPECT TO TIMING. IN TERMS OF TSRA
COVERAGE, THE HIGHEST POTENTIAL AT THIS TIME IS OUTLINED ACROSS
SE PA (MDT/LNS) WHERE ENOUGH INSTABILITY WILL BE PRESENT IN
ORDER FOR SOME MENTIONS IN THE TAF. AT THIS TIME, HAVE TRENDED
TOWARDS PROB30S; HOWEVER, IF THE COLD FRONTAL PASSAGE TRENDS
QUICKER THAN FORECAST, COULD SEE MENTIONS REMOVED AT MDT/LNS IN
FUTURE TAF PACKAGES.
OUTLOOK...
THU...LINGERING SHOWERS ACROSS S PA, RESTRICTIONS POSSIBLE.
FRI...RESTRICTIONS LIKELY WITH RAIN MOVING IN FROM SOUTH TO
NORTH, LASTING INTO FRI NIGHT.
SAT-SUN...RESTRICTIONS LIKELY WITH RAIN.
CLIMATE
THE FOLLOWING CLIMATE SITES ACROSS CENTRAL PENNSYLVANIA SET NEW
DAILY HIGH TEMPERATURE RECORDS FOR MAY 18TH:
* A RECORD HIGH TEMPERATURE OF 92 DEGREES WAS SET IN ALTOONA,
BREAKING THE PREVIOUS RECORD OF 91 DEGREES INITIALLY SET BACK
IN 1962. THIS RECORD WAS TIED TWO TIMES PREVIOUSLY, BACK IN
1996 AND 2017.
* A RECORD HIGH TEMPERATURE OF 86 DEGREES WAS SET IN BRADFORD,
BREAKING THE PREVIOUS RECORD OF 85 DEGREES SET BACK IN 1962.
---------------------------------------------
AS OF THE 5PM DAILY CLIMATE REPORTS ON MAY 19TH, TWO STATIONS
ACROSS CENTRAL PENNSYLVANIA HAVE *POTENTIALLY* BROKEN THEIR
WARMEST LOW TEMPERATURE RECORDS FOR MAY 19TH:
* HARRISBURG HAS AN OBSERVED LOW TEMPERATURE OF 68 DEGREES,
WHICH WOULD BREAK THE PREVIOUS RECORD OF 67 DEGREES SET IN
2017.
* BRADFORD HAS AN OBSERVED LOW TEMPERATURE OF 61 DEGREES, WHICH
WOULD BREAK THE PREVIOUS RECORD OF 60 DEGREES SET IN 1998.
** PLEASE NOTE THE TWO ABOVE *POTENTIAL* RECORDS ARE NOT
FINALIZED UNTIL THE MIDNIGHT CLIMATE REPORTS ARE SENT OUT,
WHICH SHOULD OCCUR SOMETIME AROUND ~2AM 5/20.
CTP WATCHES/WARNINGS/ADVISORIES
NONE.
WHAT HAS CHANGED...LAMBERT/STEINBUGL/BAUCO
KEY MESSAGES...LAMBERT/STEINBUGL/BAUCO
DISCUSSION...LAMBERT/STEINBUGL/BAUCO
AVIATION...BEATY
CLIMATE...BEATY
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