725
FXUS61 KCTP 191100
AFDCTP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
700 AM EDT TUE MAY 19 2026
WHAT HAS CHANGED
* INCREASING ODDS FOR A NOTICEABLY COOLER AND RATHER WET START
TO MEMORIAL DAY WEEKEND
KEY MESSAGES
1) SUMMERLIKE HEAT WAVE PEAKS TODAY WITH RECORD CHALLENGING
TEMPERATURES IN THE MID 80S TO MID 90S
2) SCATTERED STRONG TO SEVERE THUNDERSTORMS ARE POSSIBLE ACROSS
NORTH CENTRAL PA LATER TODAY/TONIGHT AND SOUTH CENTRAL PA
WEDNESDAY AFTERNOON
3) MAJOR COOLDOWN ARRIVES THURSDAY AND LASTS INTO MEMORIAL DAY
WEEKEND WITH WIDESPREAD SOAKING RAINFALL LIKELY FRIDAY AND
SATURDAY
DISCUSSION
KEY MESSAGE 1: SUMMERLIKE HEAT WAVE PEAKS TODAY WITH RECORD
CHALLENGING TEMPERATURES IN THE MID 80S TO MID 90S
ANOTHER SCORCHER TODAY WITH MAX TEMPS 85-95F APPROACHING DAILY
RECORDS (SEE CLIMATE SECTION). MAX HEAT INDICES ARE FCST TO
REACH THE UPPER 90S OR JUST SHY OF HEAT ADVY CRITERIA ACROSS THE
LSV. RECORD HI MINIMUM TEMPS ARE ALSO ON THE TABLE TODAY AND
WEDNESDAY.
--------------------------------------------------------------
KEY MESSAGE 2: SCATTERED STRONG TO SEVERE THUNDERSTORMS ARE
POSSIBLE ACROSS NORTH CENTRAL PA LATER TODAY/TONIGHT AND SOUTH
CENTRAL PA WEDNESDAY AFTERNOON
MOIST AND UNSTABLE PRE-FRONTAL AIRMASS WILL BE SUPPORTIVE OF
WIDELY SCATTERED THUNDERSTORMS THIS AFTERNOON THROUGH THE
EVENING. HOWEVER, MARGINAL DEEP LAYER SHEAR VALUES SUGGEST THE
PRIMARY SEVERE RISK IS PROBABLY LATER TONIGHT OVER THE NW/NC
MTNS AHEAD OF THE SFC COLD FRONT CROSSING LAKE ERIE. CONVECTIVE
FOCUS SHIFTS TO SOUTH CENTRAL PA ON WEDNESDAY 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.
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KEY MESSAGE 3: 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.
WE MAY NOT BE BEARISH ENOUGH ON DAYTIME TEMPERATURES. IT ALSO
APPEARS PROBABLE THAT PERIODS OF SOAKING RAIN 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 /12Z TUESDAY THROUGH SATURDAY/
PATCHY LOW-LYING FOG HAS DEVELOPED IN SPOTS WHERE RAIN FELL
OVERNIGHT & SKIES BRIEFLY CLEARED OUT. THIS FOG SHOULD CLEAR OUT
BY 13Z-14Z AS DAYLIGHT MIXES OUT THE BOUNDARY LAYER. OTHERWISE,
PREVAILING VFR IS FAVORED THROUGH THE 12Z TAF PERIOD, WITH THE
MAIN EXCEPTIONS BEING VISIBILITY RESTRICTIONS IN ANY HEAVIER
SHOWERS/THUNDERSTORMS THAT DEVELOP & CLOUD CEILINGS LOWERING TO
MVFR-IFR ACROSS THE NORTHERN TIER (KBFD) AFTER 06Z WEDNESDAY.
CHANCES FOR SPOTTY SHOWERS/THUNDERSTORMS WILL PICK UP AGAIN
THIS AFTERNOON AND EVENING, PRIMARILY BETWEEN 16Z-00Z, AS WEAK
SHORTWAVES MOVE ACROSS THE PERIPHERY OF A RIDGE OVER THE WESTERN
ATLANTIC. SIMILAR TO YESTERDAY, GUSTY WINDS MAY ACCOMPANY THESE
SPOTTY SHOWERS/STORMS GIVEN THE MODERATELY UNSTABLE AIRMASS
(HREF MEAN SBCAPE AROUND 1000-1500 J/KG) AND STEEP LOW-LEVEL
LAPSE RATES (>8 C/KM) IN PLACE, THOUGH PLACEMENT/TIMING
UNCERTAINTIES REMAIN GIVEN THE WEAK FORCING MECHANISMS IN PLACE.
MOST CONVECTION WILL DIMINISH AFTER 00Z WEDNESDAY WITH THE LOSS
OF DAYTIME HEATING, THOUGH SOME MODELS ARE HINTING AT AN MCS
ASSOCIATED WITH AN APPROACHING COLD FRONT REACHING KBFD AROUND
03Z-06Z WEDNESDAY, BRINGING THE POTENTIAL FOR GUSTY WINDS AND
VISIBILITY RESTRICTIONS. MCS TIMING AND IMPACTS WILL BE
SENSITIVE TO ITS DEVELOPMENT/EVOLUTION ACROSS THE OHIO VALLEY
THIS AFTERNOON & EVENING, WITH TAF MENTIONS NOT INCLUDED AT THIS
TIME GIVEN HIGH MODEL VARIABILITY.
LASTLY, LLWS MENTIONS WERE INCLUDED AT OUR NORTHERN TERMINALS
(KBFD/KIPT) THROUGH THE EVENING/OVERNIGHT HOURS AS 900 MB WINDS
INCREASE TO AROUND 40 KTS DUE TO PRESSURE GRADIENT BETWEEN LOW
PRESSURE OVER SOUTHERN CANADA & BERMUDA HIGH OVER THE WESTERN
ATLANTIC.
OUTLOOK...
WED...RESTRICTIONS PROBABLE THROUGH WEDNESDAY NIGHT WITH
WIDESPREAD SHOWERS/STORMS ALONG CFROPA.
THU...LINGERING SHOWERS ACROSS S PA, RESTRICTIONS POSSIBLE.
FRI...RESTRICTIONS LIKELY WITH RAIN MOVING IN FROM SOUTH TO
NORTH, LASTING INTO FRI NIGHT.
SAT...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.
** NOTE: THE HIGH TEMPERATURE FOR STATE COLLEGE WILL BE REPORTED
AROUND 7AM ON 5/19. THIS IS DUE TO THE STATE COLLEGE CO-OP
OBSERVATIONS RUNNING 7AM-7AM. THUS, TODAY'S (5/18) HIGH
TEMPERATURE WILL BE REPORTED IN TOMORROW'S (5/19) OBSERVATION.
THIS RECORD, FOR REFERENCE, IS 92 DEGREES SET IN 1962.
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ABNORMALLY WARM TEMPERATURES WILL CONTINUE ON MAY 19TH, THUS
MULTIPLE SITES COULD CHALLENGE DAILY RECORD HIGH TEMPERATURES.
DAILY MAXIMUM HIGH TEMPERATURES FOR MAY 19TH:
* HARRISBURG: 95F SET IN 1962
* WILLIAMSPORT: 96F IN IN 1996
* ALTOONA: 92F SET IN 1996
* BRADFORD: 85F SET IN 1962
* STATE COLLEGE: 92F SET IN 1934, TIED IN 1996.
CTP WATCHES/WARNINGS/ADVISORIES
NONE.
WHAT HAS CHANGED...STEINBUGL
KEY MESSAGES...STEINBUGL
DISCUSSION...STEINBUGL
AVIATION...TEARE
CLIMATE...BEATY
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