436
FXUS61 KCTP 220119
AFDCTP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
919 PM EDT SAT MAR 21 2026
WHAT HAS CHANGED
FORECAST IS ON TRACK FOR SEVERE WEATHER POTENTIAL ACROSS CENTRAL
AND SOUTHERN PA (RISK LEVEL 2 - SLGT) FOR SUNDAY AFTERNOON AND
EARLY EVENING.
KEY MESSAGES
1) FIRST WEEKEND OF SPRING WARMUP PRECEDES RAIN AND A SEVERE
THUNDERSTORM RISK SUNDAY AFTERNOON INTO SUNDAY NIGHT.
DISCUSSION
KEY MESSAGE 1: FIRST WEEKEND OF SPRING WARMUP PRECEDES RAIN AND
A SEVERE THUNDERSTORM RISK SUNDAY AFTERNOON INTO SUNDAY NIGHT.
A NICE START TO SPRING THIS WEEKEND WITH FCST HIGHS RAMPING 15
TO 30F ABOVE THE HISTORICAL AVERAGE BY SUNDAY. THIS SURGE OF
WARMTH WILL BE BRIEF AND FOLLOWED BY A NOTICEABLE COOLDOWN ON
MONDAY WITH MAX TEMPS 20-30 DEGREES LOWER THAN SUNDAY.
MAIN FACTOR FOR STRONG STORMS ON SUNDAY WILL BE RATHER WARM
TEMPERATURES ACROSS THE SOUTHERN HALF OF THE CWA. SFC DEWPOINTS,
CURRENTLY IN THE 50S ACROSS SRN ILL THROUGH MUCH OF KY WILL
SURGE NE TWD THE CWA VERY LATE TONIGHT AND SUNDAY AS DEEP LAYER
SHEAR INCREASES DRAMATICALLY.
T/TD SPREAD OF 15-20 DEG F (LOW-MID 70S AND LOW-MID 50S
RESPECTIVELY) SUGGESTS THE POTENTIAL FOR MORE OF AN INVERTED V
PROFILE, WHERE THIS IN COMBINATION WITH FAST CELL MOVEMENT CAN
SUPPORT STRONG WIND GUSTS. 0-3 KM BULK SHEAR VALUES OF AROUND 50
KTS FROM THE WEST AHEAD OF THE SSE MOVING COLD FRONT AND 0-1 KM
ML CAPE OF 1500-2000 J/KG SHOULD PROVIDE AMPLE CONVECTIVE AND
KINEMATIC ENERGY TO SUPPORT WIND GUSTS OF 40+ KTS WITH MOST OF
THE STORMS, WHILE THE TALLER STORMS AND COLLAPSING RAIN CORES
WILL LEAD TO SOME 50+ KT GUSTS AND LOCALIZED WIND DAMAGE.
SOME INDICATIONS THAT SOME SPOTS COULD GET SOME HIGHER QPF AMTS.
HOWEVER, THIS MAY BE LIMITED BY FAST CELL MOVEMENT AND IF ANY
CELLS CAN TRAIN OVER THE SAME AREA. ALSO NOT REAL WET ACROSS
THE SOUTH.
OTHER THING TO WATCH IS ANOTHER ROUND OF SNOW POSSIBLE LATER
SUNDAY NIGHT INTO MONDAY MORNING. LAST 2 EVENTS RESULTED IN
SNOW EITHER IN OUR AREA OR NEARBY CWA AREAS.
EARLIER DISCUSSION BELOW.
SPC EXPANDED THE LEVEL 2/SLIGHT RISK OUTLOOK FROM THE UPPER
OHIO VALLEY INTO SOUTH CENTRAL PA (SOUTH OF I-80) FOR SUNDAY
AFTERNOON AND EVENING. CAPE AND 0-6KM SHEAR PROFILES APPEAR
RATHER FAVORABLE FOR ORGANIZED SEVERE STORMS AHEAD OF A
SOUTHEASTWARD ADVANCING COLD FRONT. LARGE HAIL PROBS ARE
RELATIVELY HIGH WITH 700-500MB LAPSE RATES 7-7.5 C/KM AND
ESSENTIALLY MATCH THE DAMAGING WIND PROBS.
SECONDARY FRONTAL WAVE DEVELOPMENT NEAR THE DELMARVA/SRN NJ
SHOULD HOLD UP THE COLD FRONT AND ALLOW COLDER TEMPS TO
BLEED/CREEP SOUTHWARD LATE SUNDAY NIGHT INTO MONDAY MORNING.
THIS SHOULD RESULT IN A RAIN/SNOW MIX OR CHANGEOVER TO WET SNOW
ALONG THE NORTHERN EDGE OF THE FRONTAL PRECIP BAND AS IT EXITS
THE AREA. A COATING OF SNOW UP TO 0.5" IS MOST LIKELY ON NON-
PAVED SFCS ACROSS THE NORTHERN TIER BY 12Z MONDAY. HIGH TEMPS
ON MONDAY ARE PROJECTED TO BE 20 TO 30 DEGREES COLDER THAN
SUNDAY, PUNCTUATED BY A CHILLY AND BRISK/GUSTY NW WIND.
THE REST OF NEXT WEEK SHOULD FEATURE MORE TEMPERATURE SWINGS UP
AND DOWN WITH OCCASIONAL LIGHT PRECIP. THE BEST PRECIP SIGNAL IN
THE 21/00Z MODEL CYCLE IS IN THE LATE THURSDAY/THURSDAY NIGHT
TIMEFRAME.
AVIATION /00Z SUNDAY THROUGH THURSDAY/
VFR CONDITIONS ARE EXPECTED THROUGH THE NIGHT AND MOST OR ALL OF
SUNDAY MORNING ACROSS CENTRAL AND SW PA (KUNV, KAOO AND KJST) WITH
INCREASING MAINLY MID AND HIGH LEVEL CLOUD COVER.
LOW-LEVEL FLOW BECOMES SOUTHEASTERLY OVERNIGHT AS HIGH PRESSURE
EXITS THE REGION TO THE EAST, WHICH WILL ALLOW FOR LOW CLOUDS
TO WORK THEIR WAY INTO EASTERN PA AFTER 06Z. THIS SHOULD BRING A
PERIOD OF MVFR OR IFR CONDITIONS TO IPT, MDT, AND LNS INTO
SUNDAY MORNING. A SW TO WSW, 40 TO 55 KNOT LOW-LEVEL JET WILL
LEAD TO LLWS CONCERNS LATE TONIGHT THROUGH THE MID MORNING
HOURS SUNDAY FOR ALL TAF SITES.
CLOUDS LOWER ACROSS NORTHERN PA THROUGH THE MORNING, WITH
CEILINGS AT BFD LIKELY BECOMING MVFR BY 14-16Z AS A FEW SHOWERS
MOVE INTO THE AREA NEAR AND IN ADVANCE OF A COLD FRONT. VFR
CONDITIONS WILL RETURN ACROSS EASTERN PA BY LATE SUN MORNING,
AS THE LOW CLOUDS DISSIPATE.
NUMEROUS THUNDERSTORMS SHOULD DEVELOP AHEAD OF A COLD FRONT
AFTER 18Z ON SUNDAY, PARTICULARLY FOR AREAS SOUTH OF INTERSTATE
80 WHERE THE BEST COMBINATION OF WIND SHEAR AND INSTABILITY WILL
EXIST DUE TO THE WARMEST TEMPS AND SFC DEWPOINTS. THESE STORMS
WILL BE CAPABLE OF PRODUCING STRONG WIND GUSTS (OVER 45 KTS) FROM
THE WEST TO WEST-NORTHWEST AND PERHAPS A FEW INSTANCES OF LARGE
HAIL.
OUTLOOK...
MON...RAIN GRADUALLY TAPERS OFF NORTH TO SOUTH, TRANSITION TO
SNOW POSSIBLE MAINLY NORTH OF I-80 (BFD/IPT). RESTRICTIONS
POSSIBLE WITHIN RAIN/SNOW SHOWERS.
TUE...MAINLY DRY WITH VFR CONDITIONS. SLIGHT CHANCE OF SNOW
SHOWER ACROSS NORTHERN PA LATE WHICH COULD BRING SOME
RESTRICTIONS.
WED...A FEW RAIN SHOWERS ACROSS NORTHERN PA.
THU...RAIN WITH RESTRICTIONS POSSIBLE.
CLIMATE
DAILY RECORD HIGH TEMPERATURES FOR MARCH 22:
HARRISBURG 80 IN 1938
WILLIAMSPORT 82 IN 1938
ALTOONA 81 IN 1966
STATE COLLEGE 80 IN 1938
CTP WATCHES/WARNINGS/ADVISORIES
NONE.
WHAT HAS CHANGED...LAMBERT/MARTIN
KEY MESSAGES...LAMBERT/STEINBUGL/MARTIN
DISCUSSION...LAMBERT/STEINBUGL/MARTIN
AVIATION...LAMBERT/BAUCO
CLIMATE...STEINBUGL
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