653
FXUS61 KPBZ 010143
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
943 PM EDT MON MAR 31 2025
SYNOPSIS
DRIER WEATHER AND COOL TEMPERATURES ARE EXPECTED TUESDAY WITH
HIGH PRESSURE. SEVERE WEATHER POTENTIAL AND HEAVY RAINFALL ARE
EXPECTED MID TO LATE WEEK.
NEAR TERM /THROUGH TUESDAY/
KEY MESSAGES:
- DRIER CONDITIONS AND BELOW AVERAGE TEMPERATURES EXPECTED
TUESDAY
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EARLY MORNING TEMPERATURES ON TUESDAY WILL LIKELY RANGE BETWEEN
35F TO 25F ACROSS THE REGION AS 850MB TEMPS DROP TO
-3 TO -4 DEGREES CELSIUS IN THE WAKE OF A COLD FRONT. SKY
CONDITIONS WILL LIKELY REMAIN MOSTLY CLOUDY.
DRY CONDITIONS, WITH SLIGHTLY BELOW AVERAGE TEMPERATURES, ARE
EXPECTED LATE TUESDAY MORNING INTO THE EVENING AS THE OHIO RIVER
VALLEY REMAINS UNDER AN UPPER-LEVEL TROUGH. CLOUDS WILL LIKELY
ERODE LATE MORNING WITH DIURNAL MIXING.
SHORT TERM /TUESDAY NIGHT/
KEY MESSAGES:
- ABOVE AVERAGE TEMPERATURES RETURN TUESDAY NIGHT
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CONFIDENCE REMAINS HIGH THAT TUESDAY NIGHT WILL BE DRY WITH LOW
AND MID-LEVEL SUBSIDENCE. TEMPERATURES WILL TREND ABOVE AVERAGE
WITH A SHIFT IN THE SYNOPTIC PATTERN, WINDS SHIFT WILL BE
REDIRECTED FROM THE SOUTH/SOUTHEAST AS A NEW LOW PRESSURE
SYSTEM DEVELOPS OUT OF THE ROCKIES AND TRACKS INTO THE MIDWEST.
LONG TERM /WEDNESDAY THROUGH MONDAY/
KEY MESSAGES:
- ABOVE AVERAGE TEMPERATURES WEDNESDAY THROUGH SATURDAY
- SEVERE THUNDERSTORM POTENTIAL WEDNESDAY AND THURSDAY
- POTENTIAL FOR HEAVY RAIN THURSDAY INTO SATURDAY
- QUIETER WEATHER POSSIBLE SUNDAY/MONDAY; RIVERS MAY REMAIN
ELEVATED THOUGH
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ENSEMBLES ARE SUGGESTING THAT THERE IS HIGH CONFIDENCE IN RIDGING
SETTING UP OFF OF THE SOUTHEAST CONUS COAST STARTING ON WEDNESDAY
AND LASTING INTO THE WEEKEND. THIS WOULD LIKELY SET UP PERSISTENT
SOUTHWEST FLOW ALOFT ACROSS THE OHIO VALLEY. A FRONTAL BOUNDARY WILL
LIKELY ADVANCE INTO THIS AREA AND STALL GENERALLY FROM THURSDAY INTO
THE WEEKEND, WITH SOME WOBBLES IN ITS POSITION DURING THIS PERIOD.
THIS FRONT WILL PRESENT THE POTENTIAL FOR BOTH SEVERE WEATHER AND
FLOODING THREATS.
THE BOUNDARY FIGURES TO APPROACH THE REGION WEDNESDAY EVENING, WITH
PERHAPS A STRONGLY-FORCED LINE OF STORMS IN OR NEAR EASTERN OHIO
APPROACHING AS EARLY AS THE AFTERNOON. ENSEMBLES HAVE LITTLE
DOUBT THAT THERE WILL BE SUFFICIENT DEEP-LAYER SHEAR, WITH THE
VAST MAJORITY OF MEMBERS SUGGESTING AT LEAST 50 KNOTS IN THE
SURFACE TO 500MB LEVEL. CAPE LEVELS ARE MORE UNCERTAIN, WITH
BEST PROBABILITIES OF A FEW HUNDRED J/KG (GREATER THAN 30
PERCENT OR SO) TO THE WEST OF I-77. PROBABLY NOT COINCIDENTALLY,
THIS IS WHERE SPC HAS A DAY 3 SLIGHT RISK OUTLINED (AS DOES CSU
MLP GUIDANCE), WITH A MARGINAL RISK ACROSS THE REMAINDER OF OUR
CWA, WHERE STORMS WOULD TRAVERSE DURING A PERIOD OF DIURNAL
STABILIZATION. A DAY 4 SEVERE RISK IS ALSO OUTLINED FOR THE
MAJORITY OF THE CWA AS THE FRONT LINGERS, WITH BUOYANCY ONCE
AGAIN MORE UNCERTAIN THAN SHEAR. AREAS SOUTH OF PITTSBURGH MIGHT
HAVE A BIT HIGHER THREAT.
THE SIGNALS FOR HEAVY RAIN WITH THIS FRONT ARE CERTAINLY THERE. AN
EXTENDED PERIOD OF PRECIPITABLE WATER VALUES NEAR OR ABOVE THE TOP
END OF CLIMATOLOGY IS POSSIBLE FROM WEDNESDAY NIGHT THROUGH
SATURDAY, AND WITH LIKELY PERIODS OF CONVERGENT FLOW WITH THE FRONT,
THERE IS POTENTIAL FOR SOME IMPRESSIVE 72-HOUR RAINFALL TOTALS,
PARTICULARLY IN EASTERN OHIO. GEFS M-CLIMATE PROGS ALSO SHOW THE
POTENTIAL FOR AN AXIS OF RAINFALL EXTENDING INTO FAR WESTERN PA
THAT COULD EXCEED THE 20-YEAR CLIMATOLOGY RELATIVE TO GEFS
REFORECASTS - BOTTOM LINE, A POTENTIALLY SIGNIFICANT RAINFALL
EVENT FOR THE OHIO VALLEY. WHILE THE POSSIBLE RAINFALL TOTALS
GENERALLY ARE HIGHER TO OUR SOUTHWEST, NBM PROBABILITIES OF 2
INCHES OR MORE OF TOTAL RAIN FROM 8 AM THURSDAY THROUGH 8 AM
SATURDAY ARE 50 PERCENT OR GREATER IN EASTERN OHIO, AND SLOWLY
DROP OFF EAST OF THE PA/OH BORDER. 90TH PERCENTILE VALUES OF 3
TO 4 INCHES SHOW UP DURING THIS PERIOD, WHICH COULD REPRESENT
VALUES IN A RELATIVELY SMALL BAND WHERE CONVECTION ENDS UP BEING
MOST FAVORED. FLASH FLOODING MAY BECOME A CONCERN IN SPOTS
DEPENDING ON WHERE THE HEAVIER AXIS OF CONVECTION SETS UP. LONG-
RANGE ENSEMBLE RIVER GUIDANCE ALSO SHOWS THE POTENTIAL FOR
PLENTY OF STRONG RISES ON AREA RIVERS, WITH AT LEAST ACTION
STAGES POSSIBLE FOR MUCH OF THE AREA, WITH SOME POTENTIAL FOR
MINOR RIVER FLOODING IN AT LEAST EASTERN OHIO. IT'S STILL A BIT
TOO EARLY FOR ANY FLOOD WATCHES, BUT THESE MAY BECOME NECESSARY
OVER THE NEXT DAY OR TWO.
ABOVE-NORMAL TEMPERATURES WILL ACCOMPANY ALL OF THIS RAIN INTO
THE WEEKEND. IMPROVEMENT IN THE WEATHER PATTERN IS POSSIBLE BY
SUNDAY OR MONDAY AS A STRONGER GREAT LAKES SHORTWAVE COULD
FINALLY KICK THE BOUNDARY TO THE EAST, ALTHOUGH THERE IS MODEL
DISAGREEMENT THIS FAR OUT ON TIMING AND STRENGTH. BELOW-NORMAL
TEMPERATURES COULD RETURN WITH SOME OF THESE SOLUTIONS, ALONG
WITH A DRIER PATTERN.
AVIATION /02Z TUESDAY THROUGH SATURDAY/
MVFR CONDITIONS WILL REMAIN THE THEME THROUGH TONIGHT IN THE
WAKE OF THE COLD FRONT UNDER NORTHWEST FLOW. WITH A TIGHT
PRESSURE GRADIENT AND A WELL MIXED BOUNDARY LAYER, WIND GUSTS
20-25KTS COULD LINGER THROUGH 12Z.
WITH DAYTIME MIXING ON TUESDAY, THE MOISTURE WILL ERODE AND VFR
CONDITIONS RETURN WITH HIGH CONFIDENCE IN THE MORNING HOURS.
ASIDE FROM SOME CIRRUS STREAMING IN AT THE END OF THE CURRENT
TAF PERIOD, SKIES WILL BE MOSTLY CLEAR BY THE AFTERNOON HOURS.
OUTLOOK...
LOW PRESSURE MAY BRING ANOTHER ROUND OF RAIN AND RESTRICTIONS
WEDNESDAY INTO THURSDAY WITH AN UNSETTLED PATTERN CONTINUING TO
CLOSE OUT THE WEEK.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...NONE.
OH...NONE.
WV...NONE.
SYNOPSIS...HEFFERAN
NEAR TERM...HEFFERAN
SHORT TERM...HEFFERAN
LONG TERM...CL
AVIATION...HEFFERAN/MLB
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