802
FXUS61 KPBZ 291641
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
1241 PM EDT SAT MAR 29 2025
SYNOPSIS
ABOVE NORMAL TEMPERATURES THIS WEEKEND WITH INCREASING RAIN AND
THUNDERSTORM CHANCES SUNDAY AND MONDAY. DRY TUESDAY WITH
SLIGHTLY BELOW NORMAL TEMPERATURES AHEAD OF ANOTHER WARMUP AND
UNSETTLED WEATHER TO CLOSE OUT THE WEEK.
NEAR TERM /THROUGH TONIGHT/
KEY MESSAGES:
- SCATTERED LIGHT RAIN SHOWERS BUT LARGELY DRY.
- WELL ABOVE AVERAGE AFTERNOON HIGHS AND OVERNIGHT LOWS.
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DESPITE WEAK RIDGING ALOFT, BROAD UPPER DIFFLUENCE AND WEAK
SHORTWAVE WITH AN INCREASE IN MID-LEVEL MOISTURE AROUND 700 MB
IN WSW FLOW HAS MAINTAINED AN INCREASE IN RADAR RETURNS ACROSS
THE AREA EARLY THIS AFTERNOON, BUT COPIOUS SUB-CLOUD DRY AIR IS
PREVENTING MOST OF THIS FROM REACHING THE GROUND WITH SURFACE
DEW POINT DEPRESSIONS OF 15-20 DEGREES. A FEW OBS OF DRIZZLE AND
LIGHT RAIN HAVE BEEN REPORTED, BUT WITHOUT SUFFICIENT
SATURATION OF THE LOWER LEVELS AND WEAK LIFT, DON'T ANTICIPATE
THAT ANY NOTABLE RAIN AMOUNTS WILL COME FROM THIS. DESPITE THE
LESS THAN FAVORABLE ENVIRONMENT, SOME NARROW EMBEDDED UPDRAFTS
HAVE BEEN ABLE TO UTILIZE FUMES OF ELEVATED INSTABILITY TO
GENERATE SOME THUNDER, BUT WITH ACARS SOUNDINGS SHOWING A CAP
AROUND 550 MB, UPDRAFTS SHOULDN'T EXCEED ~15KFT WHICH ISN'T OF
CONCERN FOR ANY HAIL OR WIND THREAT. THE SURFACE WARM FRONT AND
BEST LOW LEVEL CONVERGENCE IS ANALYZED OFF TO OUR NORTH, AND
LOCALLY OUR 12Z SOUNDING SHOWS INCREASED MOISTURE IN THE 700-550
MB LAYER SUPPORTING THE THICKENING OF MID-LEVEL CLOUD COVERAGE
THAT WILL PERSIST THROUGH THE DAY TODAY.
THE REGION WILL BE WELL INTO THE WARM SECTOR TODAY, SO EXPECT
HIGH TEMPERATURES 20 TO 25 DEGREES ABOVE NORMAL. CLOUD COVERAGE
WILL BE THE ONLY THING HAMPERING AFTERNOON HIGH TEMPERATURES AS
STOUT SOUTHWEST FLOW PROMOTES WARM ADVECTION. NBM PROBS FOR MAXT
>75 ARE 60 TO 100% SOUTH OF I-80, SO WILL BUMP HIGH
TEMPERATURES ABOVE THE NBM MEAN POINTING TOWARD LOCATIONS FROM
PITTSBURGH AND SOUTH FLIRTING WITH 80 DEGREES.
TONIGHT, SURFACE LOW PRESSURE WILL DEEPEN OFF TO OUR WEST AND
BEGIN TO SLIDE TOWARD THE GREAT LAKES REGION. AS IT DOES SO,
IT'LL DRAG THE WARM FRONT FARTHER NORTH AND LOCALLY INCREASE THE
PRESSURE GRADIENT. DESPITE BOUNDARY LAYER DECOUPLING OVERNIGHT,
WEAK WARM ADVECTION IN GRADIENT-INDUCED SOUTHERLY FLOW WILL
PROVIDE ABOVE NORMAL LOW TEMPERATURES AND CHALLENGE SOME RECORD
LOW MINTS (60F AT PIT, 59F AT HLG, 59F AT PHD).
SHORT TERM /SUNDAY THROUGH MONDAY/
KEY MESSAGES:
- SHOWER/STORM CHANCES INCREASE SUNDAY AND MONDAY
- UNCERTAINTY TO SEVERE THREAT AND TIMING OF FRONT
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RIDGE WILL SLOWLY BREAK DOWN ON SUNDAY AS A SHORTWAVE TROUGH,
STREAKING NORTHEASTWARD IN THE SOUTHWESTERLY FLOW ALOFT, WILL
CROSS THE REGION SUNDAY AFTERNOON. EXPECT AN AREA OF SHOWERS TO
DEVELOP AHEAD OF THE WAVE AND SPREAD ACROSS THE UPPER OHIO
VALLEY SUNDAY MORNING. SHOWERS WILL LIKELY CONTINUE THROUGH MOST
OF THE DAY AS A PLUME OF DEEP MOISTURE WILL DRIVE NORTHEASTWARD
ON THE WESTERN FLANK OF THE EASTWARD DRIFTING RIDGE. DONT SEE
MUCH ATMOSPHERIC DESTABILIZATION UNTIL LATE IN THE DAY, SO
WOULD THINK THE RISK FOR THUNDERSTORMS WOULD INCREASE DURING THE
LATE AFTERNOON AND THROUGH THE EVENING. THE INSTABILITY IS NOT
OVERLY IMPRESSIVE (200-500 J/KG) WITH THE STRONGEST BUOYANCY
OVER PORTIONS OF EASTERN OHIO. THE HEADACHE WILL BE THAT AN
UPPER LEVEL DRY SLOT WILL PASS OVER THE REGION SUNDAY EVENING
WHICH MAY LEAD TO A DECREASE IN ACTIVITY FOR A PORTION OF THE
EVENING AND OVERNIGHT HOURS.
THE BIG QUESTIONS COME SUNDAY NIGHT AND MONDAY MORNING. THE COLD
FRONTS EASTERN PROGRESSION WILL SLOW SUNDAY NIGHT AS THE RIDGE
WILL NOT EASILY GIVE WAY AND THE MAIN TROUGH AXIS WILL BE WELL
TO THE NORTHWEST OF THE SURFACE BOUNDARY. SINCE WE EXPECT MUCH
OF THE CONVECTION TO BE DRIVEN BY THE SURFACE FRONT, IT MAY BE
TOO FAR WEST TO HAVE THAT MUCH OF AN INFLUENCE UNTIL VERY LATE
SUNDAY NIGHT OR EVEN MONDAY. THE OTHER ISSUE IS THAT MOST, IF
NOT ALL OF THE MODEL DATA, IS IN AGREEMENT THAT THE ATMOSPHERE
WILL STABILIZE SUNDAY NIGHT, WHICH COULD FORCE THE CONVECTION
ALONG THE FRONT TO BE FORCED TO AN AREA WITH HIGHER BUOYANCY.
MODELS ARE PORTRAYING A SCENARIO WHERE THE CONVECTION OVER
WESTERN OHIO WILL DIVE SOUTHEASTWARD TOWARD KY AN TN, WHERE
MUCH MORE UNSTABLE AIR WILL REST. THIS COULD LEAD TO AN OUTCOME
WHERE WESTERN AND SOUTHERN PORTIONS OF THE FORECAST AREA GET
CLIPPED WITH STRONGER STORMS. STILL A LOT OF UNCERTAINTY ON THE
THREAT FOR STRONG TO SEVERE STORMS SUNDAY NIGHT AND WHERE THEY
MAY IMPACT.
FRONT WILL FINALLY BEGIN TO MOVE EASTWARD AT A FASTER PACE
MONDAY MORNING AS THE MAIN TROUGH AXIS WILL DIG INTO THE MIDWEST
AND GIVE THE FRONT A PUSH. THE RISK FOR SHOWERS AND STORMS WILL
CONTINUE THROUGH MONDAY, AS THE BOUNDARY FINALLY DOES EXIT TO
THE EAST MONDAY EVENING. MODELS ARE SHOWING SOME DESTABILIZATION
ON MONDAY AHEAD OF THE BOUNDARY, SO THE RISK FOR STRONG TO
SEVERE STORMS WILL CONTINUE, BUT UNCERTAINTY REMAINS HIGH.
TEMPERATURES WILL REMAIN WELL ABOVE NORMAL BOTH SUNDAY AND
MONDAY.
LONG TERM /MONDAY NIGHT THROUGH SATURDAY/
KEY MESSAGES:
- A COOL-DOWN IS MOST LIKELY MONDAY NIGHT INTO TUESDAY.
- ABOVE AVERAGE TEMPERATURES WEDNESDAY THROUGH FRIDAY.
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DRY AND COOLER CONDITIONS ARE EXPECTED TUESDAY WITH ANOTHER WARM
UP BEGINNING ON WEDNESDAY. ABOVE NORMAL TEMPERATURES ARE THEN
EXPECTED THROUGH THE END OF THE WEEK WITH AN UNSETTLED WEATHER
PATTERN RETURNING ON WEDNESDAY.
AVIATION /18Z SATURDAY THROUGH THURSDAY/
RECENT TREND IN ACARS SOUNDINGS IS SHOWING MOISTENING OF THE
MID-LEVELS SUPPORTING THE INCREASE IN CLOUD COVERAGE AND CIGS
JUST BELOW 10KFT WHICH WILL LIKELY HOLD ON FOR MOST OF THE DAY
TODAY. VFR IS EXPECTED TO BE THE RULE THROUGH TONIGHT. THE
POSSIBLE EXCEPTION REMAINS THE LOW CHANCE (~30%) FOR ISOLATED
SHOWERS ACROSS THE REGION TODAY TRAVELING ALONG A SPOKE OF MID-
LEVEL PVA; THE BEST CHANCE FOR THIS WOULD BE AT FKL/DUJ. HI RES
MODELS ARE BOUNCING BACK AND FORTH, BUT HAVE SOME EXTENT OF
DEVELOPMENT, SO HAVE INTRODUCED A PROB30 AT THOSE TWO SITES THIS
AFTERNOON.
LLWS CONCERNS REMAIN AT ALL PORTS AS DECOUPLED SURFACE WINDS
REMAIN LIGHT UNDERNEATH AN IMPRESSIVE 40-60KT LOW-LEVEL JET.
LLWS CONCERNS BEGIN TO ERODE NEAR 15Z AS THE CORE OF THE JET
FRACTURES. OUR LOW-LEVEL INVERSION IS LIKELY TO BREAK NEAR THE
SAME TIME AND KICK OFF GUSTY WIND (NEAR 30 KTS) MIXING DOWN TO
THE SURFACE FOR MUCH OF THE AFTERNOON HOURS.
AS A DIGGING CENTRAL CONUS TROUGH SHUNTS THE MID-LEVEL RIDGE
OFF TO THE EAST TONIGHT, BACKING SOUTHWESTERLY FLOW WILL
PROMOTE MOISTURE ADVECTION SATURATING THE PROFILE AND LOWERING
CIGS INTO SUNDAY MORNING. MVFR PROBS INCREASE TOWARD THE END OF
THE CURRENT TAF PERIOD, AND IT'S POSSIBLE THAT RESTRICTIONS
INITIALLY COME FROM VIS AS THE COLUMN SATURATES AND CLOUD BASES
THEN LOWER.
OUTLOOK...
RESTRICTIONS IN RAIN ARE LIKELY LATE SATURDAY NIGHT
INTO EARLY SUNDAY AFTERNOON AS AN UPPER LEVEL TROUGH MOVES
ACROSS THE REGION. SHOWER AND THUNDERSTORM POTENTIAL INCREASES
SUNDAY NIGHT AND MONDAY WITH THE APPROACH AND PASSAGE OF A COLD
FRONT. VFR RETURNS TUESDAY UNDER HIGH PRESSURE.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...NONE.
OH...NONE.
WV...NONE.
SYNOPSIS...MLB
NEAR TERM...MLB
SHORT TERM...22
LONG TERM...22
AVIATION...MLB/AK
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