301
FXUS61 KPBZ 012331
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
731 PM EDT FRI MAY 1 2026
WHAT HAS CHANGED
FROST/FREEZE HEADLINES HAVE BEEN HOISTED FOR TONIGHT ACROSS
NORTHERN WV AND WESTERN PA THAT WILL BE IN EFFECT FROM 12AM
UNTIL 8AM. FREEZE WARNINGS WERE CONCENTRATED WHERE THERE WAS A
HIGHEST CONFIDENCE IN A FREEZE TONIGHT, AND A FREEZE WATCH WAS
HOISTED FOR WHERE THERE WERE NO PRODUCTS IN PLACE TONIGHT FOR A
HEADS UP (ALTHOUGH A FREEZE IS POSSIBLE AREAWIDE TOMORROW
NIGHT).
KEY MESSAGES
1) AREAS OF FROST PLUS NEAR TO SUB-FREEZING TEMPERATURES AGAIN
POSSIBLE TONIGHT AND SATURDAY NIGHT.
2) WEATHER PATTERN REMAINS ACTIVE THROUGH THE UPCOMING WEEK WHILE
AREA TEMPERATURE GENERALLY REMAINS BELOW SEASONAL AVERAGES.
DISCUSSION
KEY MESSAGE 1...
SIMILAR TO LAST NIGHT, LIGHT WINDS AND SOME CLEARING WILL ALLOW
TEMPERATURES TO FALL INTO THE 30S, ALLOWING FOR FROST DEVELOPMENT
BY DAWN ACROSS MUCH OF THE REGION. CLOUD COVER WILL BE THE
LIMITING REAGENT IN THIS EQUATION AND MORE STOUT CLOUD COVER
CLINGING TO THE RIDGES MAY KEEP PRECLUDE WIDESPREAD FROST FROM
OCCURRING. AS SUCH, A FREEZE WARNING HAS BEEN ISSUED FOR OUR
NORTHWEST PA COUNTIES, WHERE THE PROBABILITY OF TEMPERATURES
BELOW FREEZING IS LARGELY GREATER THAN 90%. A FROST ADVISORY HAS
BEEN ISSUED FOR EASTERN OH, SOUTHWEST PA AND PORTIONS OF
NORTHERN WV, EXCLUDING THE LIKELY CLOUDIER RIDGES OF WV. MANY OF
THESE COUNTIES SEE CHANCES FOR SUBFREEZING TEMPERATURES PEAK
BETWEEN 50-70%.
SATURDAY NIGHT LOOKS TO FEATURE A MORE WIDESPREAD THREAT WITH
CONTINUED LIGHT WINDS AND SCANT CLOUD COVER OVERNIGHT FOR MOST OF
THE REGION. PROBABILITIES FOR SUBFREEZING TEMPERATURES BY DAYBREAK
ON SUNDAY ARE LARGELY GREATER THAN 70-80% FOR ALMOST OUR ENTIRE
REGION. THUS, IT SEEMS LIKELY THAT FROST/FREEZE HEADLINES ARE NEEDED
FOR MOST IF NOT ALL OF THE AREA TOMORROW NIGHT. AT THIS TIME, A
FREEZE WATCH HAS BEEN HOISTED FOR AREAS OF THE WV RIDGES THAT DO NOT
HAVE ANY FROST/FREEZE HEADLINES FOR TONIGHT BUT HAS NOT BEEN HOISTED
FOR OTHER AREAS TO AVOID ANY KIND OF OVERLAP OR CONFUSION.
KEY MESSAGE 2...
A WEAK SURFACE LOW SPURRED EASTWARD BY A SUBTLE SHORTWAVE
ROUNDING THE BASE OF THE UPPER TROUGH PARKED OVER SOUTHERN
CANADA BRINGS AREAS OF RAIN AND SHOWERS TODAY. THE PROBABILITY
OF THUNDER IS LOW BUT NOT ZERO TODAY OWING TO THE RATHER COLD
AIR IN PLACE ABOVE THE SURFACE. THE UPPER WAVE ITSELF MOVES
EASTWARD ON SATURDAY AND BRINGS A RENEWED CHANCE OF SHOWERS AND
ANOTHER WEAK CHANCE FOR THUNDER TO RUMBLE UNDER THE UPPER LOW AS
IT EXITS THE REGION. SUNDAY LOOKS DRY BEFORE ANOTHER POSSIBLE
WEAK SHORTWAVE LOOKS TO RETURN SHOWER CHANCES SUNDAY NIGHT.
YET ANOTHER UPPER TROUGH LOOKS TO PRESS ITS WAY EASTWARD NEAR
MIDWEEK AND ACCORDINGLY OUR SHOWER CHANCES RISE EACH DAY MONDAY
THROUGH WEDNESDAY WITH EMBEDDED SHORTWAVES AHEAD OF THE MAIN TROUGH
AXIS. THE MAIN TROUGH AXIS LOOKS TO SIT OVER THE REGION THROUGH MID-
TO-LATE NEXT WEEK BUT CLUSTERED ENSEMBLES SHOW VARYING DEGREES OF
POSSIBILITIES FOR ITS EXIT. NEARLY 80% OF CLUSTERED ENSEMBLES
SHOW THE MAIN TROUGH EXITING THE REGION INTO THE NORTHEAST
FRIDAY BUT THEN SHOW ADDITIONAL SHORTWAVES ROUNDING THROUGH THE
FLOW BEHIND IT. AS SUCH, IT SEEMS LIKELY THAT RAIN CHANCES AND
BELOW AVERAGE TEMPERATURES REMAIN WITH US THROUGH LATE NEXT
WEEK, WITH SLIGHT WARM UPS MONDAY AND TUESDAY IN THE MIDST OF A
LITTLE FLAT RIDGING AND PRE- FRONTAL WARMING. OUR LOWEST 24 HOUR
PROBABILITY OF PRECIPITATION LOOKS TO BE THIS SUNDAY.
DESPITE CONTINUED RAIN CHANCES, THE RATHER ACTIVE PERIOD LOOKS TO
HAVE A LOW RISK LEVEL FOR HAZARDOUS WEATHER. MEDIUM RANGE AI SEVERE
GUIDANCE POINTS TOWARDS A LOW RISK FOR SEVERE ON TUESDAY, THAT WOULD
LIKELY REQUIRE STRONGER FORCING ALONG THE PASSING COLD FRONT MARRIED
TO A BETTER FRONTAL TIMING PEAKING IN THE MID AFTERNOON. THE OTHER
POSSIBLE THREAT WOULD BE FOR A MARGINAL FLOOD RISK MATERIALIZING IF
THE FRONT IS STRONGER AND SLOWER TO CROSS THE REGION WEDNESDAY AND
WEDNESDAY NIGHT. IN THIS SCENARIO, 90TH PERCENTILE RAINFALL AMOUNTS
NEAR AND GO JUST NORTH OF 1.50-2.00 INCHES.
AVIATION /00Z SATURDAY THROUGH WEDNESDAY/
SHOWERS WILL TAPER OFF THIS EVENING AS A WEAK AREA OF LOW
PRESSURE EXITS TO THE EAST. MVFR CIGS ARE EXPECTED TO CONTINUE
FOR A FEW HOURS BEHIND THE LOW WITH LOW LEVEL MOISTURE IN PLACE.
A RETURN TO VFR IS EXPECTED FOR MOST AIRPORTS LATER THIS
EVENING, AND SOME PARTIAL CLEARING IS POSSIBLE. WIND SHOULD
BECOME CALM OVERNIGHT, AND WITH THE PARTIAL CLEARING, FOG AND
STRATUS IS LIKELY TO DEVELOP. SOME UNCERTAINTY EXISTS IN THE
AMOUNT OF CLOUD COVER AND CLEARING, WHICH WOULD AFFECT THE
EXTENT OF ANY FOG/STRATUS. FOR NOW, INCLUDED IFR FOR MOST SITES
WITH SOME ADJUSTMENTS POSSIBLE IN LATER AMENDMENTS.
IFR SHOULD IMPROVE TO MVFR STRATOCU SATURDAY MORNING, WITH
MIXING LIFTING CIGS TO VFR BY AFTERNOON. SCATTERED SHOWERS ARE
EXPECTED TO DEVELOP AS WELL WITH A CROSSING UPPER TROUGH, AND
LOW CONVECTIVE TEMPERATURES.
OUTLOOK...
VFR IS EXPECTED SATURDAY NIGHT AND SUNDAY UNDER HIGH PRESSURE.
RESTRICTION AND SHOWER POTENTIAL INCREASE LATE MONDAY INTO
TUESDAY AHEAD OF AN APPROACHING COLD FRONT. A FEW THUNDERSTORMS
ARE ALSO POSSIBLE ON TUESDAY. MORE WIDESPREAD RESTRICTIONS IN
SHOWERS ARE LIKELY TUESDAY NIGHT INTO WEDNESDAY AS A WAVE OF LOW
PRESSURE TRACKS ALONG THE COLD FRONT.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...FROST ADVISORY FROM MIDNIGHT TONIGHT TO 8 AM EDT SATURDAY FOR
PAZ020-021-029-031-073>078.
FREEZE WARNING FROM MIDNIGHT TONIGHT TO 8 AM EDT SATURDAY FOR
PAZ007>009-013>016-022.
OH...FROST ADVISORY FROM MIDNIGHT TONIGHT TO 8 AM EDT SATURDAY FOR
OHZ039>041-048>050-057>059-068-069.
WV...FROST ADVISORY FROM MIDNIGHT TONIGHT TO 8 AM EDT SATURDAY FOR
WVZ001>004-012-021-509.
FREEZE WATCH FROM LATE SATURDAY NIGHT THROUGH SUNDAY MORNING
FOR WVZ510>514.
DISCUSSION...MILCAREK/AK
AVIATION...WM
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