884
FXUS61 KPBZ 020553
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
153 AM EDT SAT MAY 2 2026
WHAT HAS CHANGED
NO CHANGES TO THE FORECAST PACKAGE WERE MADE, WITH FROST/FREEZE
HEADLINES ACTIVE FOR THIS MORNING AND ADDITIONAL HEADLINES
LIKELY TONIGHT INTO SUNDAY MORNING.
KEY MESSAGES
1) AREAS OF FROST PLUS NEAR TO SUB-FREEZING TEMPERATURES
CONTINUES THIS MORNING AND RETURN TONIGHT.
2) WEATHER PATTERN REMAINS ACTIVE THROUGH THE UPCOMING WEEK WHILE
AREA TEMPERATURE GENERALLY REMAINS BELOW SEASONAL AVERAGES.
DISCUSSION
KEY MESSAGE 1...
THOUGH A MIXTURE OF LOW STRATUS AND MID-LEVEL CLOUDS MAY LOCALLY
STUNT COOLING AND/OR FROST FORMATION, THE OVERALL THREAT OF
FROST AND AREAS OF SUB-FREEZING TEMPERATURE CONTINUE THIS
MORNING BEFORE ABATING AFTER SUNRISE.
THE UPPER TROUGH AXIS CROSSES THROUGH THE DAY TODAY, CREATING LOW
PROBABILITY LIGHT RAIN SHOWERS MAINLY IN THE LATE MORNING TO
AFTERNOON PERIOD, BEFORE EXITING EAST. THE COMBINATION OF ONE
LAST REINFORCEMENT OF THE COLDER AIR MASS BEHIND THIS AXIS WITH
CLEARING SKIES AND LIGHT WIND FAVORS ONE MORE NIGHT OF FROST AND
FREEZE CONCERNS. UPGRADE OF THE FREEZE WATCH IN THE WV HIGH
TERRAIN AREA IS LIKELY WITH ADDITIONAL FROST/FREEZE HEADLINES
ISSUED BUT WILL ALLOW CURRENT HEADLINES TO EXPIRE BEFORE
MESSAGING TONIGHT'S RISKS TO VEGETATION.
KEY MESSAGE 2...
HEIGHT RISES AND INCREASINGLY SOUTHWEST FLOW WILL MANAGE TO LIFT
AREA TEMPERATURE CLOSER TO SEASONAL AVERAGES BY MONDAY INTO
TUESDAY; EVEN THEN, ENOUGH WEAK EMBEDDED SHORTWAVE MOVEMENT MAY
PROMOTE LOWER PROBABILITY SHOWER (AND NON-ZERO THUNDERSTORM
PROBABILITY) STARTING EARLY MONDAY MORNING THROUGH TUESDAY
MORNING. ENSEMBLE MODELS AGREE IN THIS BEING JUST A PRECURSOR
TO THE LARGER PATTERN SHIFT BACK TO GREAT LAKES TROUGHING
DEVELOPING BY WEDNESDAY AND LASTING INTO THE END OF THE WORK
WEEK. RESIDENTS ACROSS THE UPPER OHIO RIVER VALLEY CAN EXPECT
MULTIPLE MORE ROUNDS OF RAIN WITH TEMPERATURE TRENDING ABOUT 10
DEGREES BELOW THE DAILY AVERAGES.
THE FINER DETAILS BOTH THE MONDAY/TUESDAY PRE-TROUGH ARRIVAL
PERIOD AND THE LATE TUESDAY/WEDNESDAY TROUGH PERIOD ARE A BIT
MORE VARIED, RESULTING IN VARIANCES IN PRECIPITATION
ONSET/ENDING AS WELL AS COVERAGE AND TOTALS. WHAT CAN BE SAID IS
HIGH CONFIDENCE IN SEVERE/FLOOD THREATS BEING VERY LOW WITH ANY
ACTIVITY THAT DEVELOPS MONDAY INTO TUESDAY MORNING. SEVERE RISKS
RISE SLIGHTLY LATE TUESDAY INTO WEDNESDAY ONLY IN THE SCENARIO
THAT THE COLD FRONT CROSSING BEST MAXIMIZES DESTABILIZATION
ATTEMPTS (HIGHLIGHTED BY 10% PROBABILITY OF ~1000 J/KG SBCAPE).
FLOOD RISKS MAY BE THE MORE NOTABLE ASPECT TO MONITOR GIVEN
FAIRLY SATURATED GROUNDS IN THE REGION AND SCENARIOS THAT SEE
REPETITION OF NARROW HEAVIER BANDS PUSHING 24-48HR TOTALS ABOVE
2", WITH CURRENT PROBABILITIES FAVORED EASTERN OH TO FAR
SOUTHWEST PA FOR SUCH AXIS DEVELOPMENT (CO-LOCATED WITH 10-20%
>2" PROBABILITY).
AVIATION /06Z SATURDAY THROUGH WEDNESDAY/
VFR WITH SCATTERING OF CLOUDS HAS BEEN THE THEME INTO THE EARLY
OVERNIGHT HOURS, BUT EXPECT THAT THAT'LL CHANGE AS WE HEAD INTO
THE MORNING HOURS ON SATURDAY. WIND SHOULD BECOME CALM
OVERNIGHT, AND WITH THE PARTIAL CLEARING, FOG AND STRATUS IS
ALREADY DEVELOPING. MID-LEVEL CLOUDS WILL SLOWLY MOVE EAST INTO
WESTERN PA, AND SHOULD HELP TO LIMIT FOG DEVELOPMENT WHERE THEY
RESIDE FOR THE LONGEST. ELSEWHERE FARTHER SOUTH AND EAST, MORE
RESIDENCE TIME IS EXPECTED WITHOUT LOW CLOUDS WHICH SHOULD FAVOR
MORE FOG DEVELOPMENT. EITHER WAY, A TOUGH FORECAST FOR THE PRE-
DAWN HOURS THAT'S HIGHLY DEPENDENT ON HOW THE EXISTING CLOUD
COVER EVOLVES. HAVE MAINTAINED IFR FOR MOST SITES BUT WILL HAVE
TO CONTINUE MONITORING THE CONDITIONS THROUGH THE OVERNIGHT
HOURS FOR NECESSARY ADJUSTMENTS TO FOG OR STRATUS RESTRICTIONS.
WHAT EVER RESTRICTIONS WE HAVE IN THE MORNING HOURS SHOULD
IMPROVE TO MVFR STRATOCU WITH MIXING LIFTING CIGS TO VFR BY
AFTERNOON. WIDELY SCATTERED SHOWERS ARE EXPECTED TO DEVELOP AS
WELL WITH A CROSSING UPPER TROUGH AND STEEP LOW-LEVEL LAPSE
RATES, BUT CONFIDENCE IN OCCURRENCE AT ANY GIVEN TERMINAL WASN'T
HIGH ENOUGH TO WARRANT ANYTHING MORE THAN A PROB30 AT THIS POINT.
WIND WILL GENERALLY RANGE BETWEEN 5-10 KNOTS OUT OF THE
SOUTHWEST.
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 UNTIL 8 AM EDT THIS MORNING FOR PAZ020-021-029-
031-073>078.
FREEZE WARNING UNTIL 8 AM EDT THIS MORNING FOR PAZ007>009-
013>016-022.
OH...FROST ADVISORY UNTIL 8 AM EDT THIS MORNING FOR OHZ039>041-
048>050-057>059-068-069.
WV...FROST ADVISORY UNTIL 8 AM EDT THIS MORNING FOR WVZ001>004-012-
021-509.
FREEZE WATCH FROM LATE TONIGHT THROUGH SUNDAY MORNING FOR
WVZ510>514.
DISCUSSION...FRAZIER
AVIATION...WM/MLB
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