617
FXUS61 KPBZ 310234 AAA
AFDPBZ
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PITTSBURGH PA
1034 PM EDT SUN MAR 30 2025
SYNOPSIS
ABOVE NORMAL TEMPERATURES CONTINUE WITH SEVERE THUNDERSTORMS
POSSIBLE TONIGHT INTO EARLY MONDAY. A BRIEF BIT OF DRIER AND
COOLER WEATHER IS EXPECTED TUESDAY. HEAVY RAINFALL IS EXPECTED
ACROSS THE OHIO RIVER VALLEY LATE WEEK.
NEAR TERM /UNTIL 6 AM MONDAY MORNING/
KEY MESSAGES:
- FEW SHOWERS THIS EVENING
- LINE OF STORMS POSSIBLE TONIGHT INTO EARLY MONDAY; DAMAGING
WIND AND ISOLATED TORNADOES ARE THE MAIN THREAT
- ABOVE AVERAGE TEMPERATURES CONTINUE
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1030 PM MESOSCALE UPDATE...
UPDATED TO ISSUE THE SEVERE THUNDERSTORM WATCH FOR PORTIONS OF
THE AREA THROUGH 3AM. THE LINE OF STORMS CONTINUES EASTWARD,
WITH A POTENTIAL FOR SEVERE STORMS OVER THE NEXT SEVERAL HOURS.
LATER TONIGHT, MUCAPE IS PROGGED TO DIMINISH, WITH A WEAKENING
TREND BY 3AM.
915 PM MESOSCALE UPDATE...
THE LATEST PIT SOUNDING CONTINUES TO SHOW FAVORABLE SHEAR FOR
MAINTAINING THUNDERSTORMS AS THEY TRACK ACROSS THE AREA TONIGHT.
THE CURRENT LINE OF STORMS WAS ALONG A PREFRONTAL TROUGH ACROSS
OH, AND WILL CONTINUE TO TRACK EASTWARD THIS EVENING. HODOGRAPHS
ARE ALSO FAVORABLE FOR ROTATING STORMS, ESPECIALLY WHERE ANY
BREAKS IN THE LINE OCCUR. LATEST SPC DAY 1 OUTLOOK HAS PUSHED
THE ENHANCED RISK SLIGHTLY TO THE EAST TONIGHT.
830 PM MESOSCALE UPDATE...
A LINE OF THUNDERSTORMS CONTINUES TO ADVANCE EASTWARD ACROSS MI,
OH, AND SOUTHEASTERN IN. THE LATEST MESOANALYSIS SHOWS THE
PORTION OF THE LINE ACROSS WEST CENTRAL AND NW OH IS PARALLEL TO
THE 0-3KM SHEAR VECTOR, RESULTING IN SOME LOSS IN INTENSITY.
GREATER SHEAR IS ANALYZED SOUTH OF THIS AREA, AND THE SHEAR
VECTOR IS MORE PERPENDICULAR TO THE LINE ORIENTATION. WOULD
EXPECT TO SEE THE NORTHERN END OF THIS LINE CONTINUE TO ADVANCE
ACROSS THE AREA WITH LESSER PROBABILITIES OF SEVERE WEATHER. THE
SOUTHERN PORTION ON THE LINE WILL LIKELY BE SLOW TO LOSE
INTENSITY AS IT APPROACHES LATER THIS EVENING AND OVERNIGHT.
WILL MONITOR THE TRENDS OVER THE NEXT FEW HOURS.
PREVIOUS DISCUSSION...
CAMS HAVE BEEN WAFFLING AROUND WITH HOW FAR EAST THE LINE
PROGRESSES BEFORE IT WEAKENS. IN GENERAL, THEY OFTEN STRUGGLE
WITH THE LIFETIME OF DECAYING CONVECTIVE COMPLEXES AND WANT TO
DISSIPATE THEM TOO QUICKLY. THAT WAS THE CASE FOR MANY SEQUENCES
OF RUNS UP TO THIS MORNING WITH DISSIPATION IN EASTERN OHIO,
BUT THE 12Z GUIDANCE FLIPPED TO A BIT MORE AGGRESSIVE WITH THE
LINE MAINTAINING ITSELF INTO WESTERN PENNSYLVANIA. HREF PROBS
FOR >500 J/KG OF CAPE CUT OFF RAPIDLY RIGHT ON A ZANESVILLE TO
COSHOCTON LINE AFTER SUNSET TONIGHT. HOWEVER, THE PROBS FOR AT
LEAST 100 J/KG HAS SHIFTED FURTHER EAST AND IS AS HIGH AS 50% UP
TO THE PA BORDER. THIS LENDS HIGHER CONFIDENCE IN IMPACTS AT
LEAST IN EASTERN OHIO, BUT STILL LESS CONFIDENCE FARTHER EAST.
KINEMATICALLY, FORECAST SOUNDINGS SUGGEST THAT THE BULK OF THE
SHEAR WILL BE PACKED IN THE LOWER 3 KM (~35 KT OF 0-3 KM SHEAR
AND ~40 KT OF 0-6 KM SHEAR), AND THERMODYNAMICALLY, A GOOD CHUNK
OF THE AVAILABLE INSTABILITY ALSO IN THE LOWER LEVELS WITH
3CAPE VALUES BETWEEN 60-100 J/KG. THIS MAY HAVE A TWO FOLD
EFFECT IN THAT 1) IT CAN HELP OVERCOME THE MARGINAL INSTABILITY
AND MAINTAIN THE LINE AND 2) SUGGESTS ANOTHER ROUND OF QLCS
TORNADO POTENTIAL, ESPECIALLY IN ANY SEGMENTS OF THE LINE THAT
BOW AND ORIENT MORE NORTHWEST TO SOUTHEAST IN ALIGNMENT WITH THE
0-3 KM SHEAR VECTOR. DAMAGING WIND WILL BE THE PRIMARY HAZARD,
BUT IN COMPARISON TO OUR LAST EVENT, THE LOW-LEVEL WIND FIELD
LOOKS LESS POTENT, SO THOSE SIGNIFICANT GUSTS TO 80+ MPH ARE
LESS LIKELY.
SHORT TERM /6 AM MONDAY MORNING THROUGH 6 PM MONDAY/
KEY MESSAGES:
- COLD FRONT EXPECTED TO CROSS THE REGION SLOWLY ON MONDAY
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BY 6AM MONDAY MORNING, SHOWERS AND STORM WILL LIKELY STILL BE
ADVANCING THROUGH THE REGION. THE COLD FRONT MAY BE POSITIONED
OVER CENTRAL OHIO, A NOTED DELAY DUE TO THE UPPER-LEVEL WIND
FIELD RUNNING PARALLEL ALONG THE FRONT.
IF THE FRONT PROGRESSIVES FASTER, THIS COULD SET UP A FAVORABLE
TIME WINDOW FOR MUCH OF OUR REGION TO AVOID THE BRUNT OF ANY
SEVERE WEATHER EARLY ON MONDAY. MODEL CONSENSUS IS VERY STRONG
IN SHOWING MOST OF THE DESTABILIZATION MONDAY WELL EAST OF THE
RIDGES TOWARDS THE I-81 CORRIDOR. THIS LEAVES A NON-ZERO BUT LOW
CHANCE THAT IMPACTFUL SEVERE STORMS CAN FIRE ALONG THE FRONT
BRIGHT AND EARLY MONDAY MORNING AS THE FRONT CROSSES THE
REMAINDER OF OUR REGION. CONFIDENCE IS HIGH THAT BY 6PM THE
FRONT WILL BE AT LEAST PASSED COUNTIES NORTHWEST AND WEST
OF ALLEGHENY COUNTY (MERCER/VENANGO/LAWRENCE/COLUMBIANA).
TEMPERATURES WILL REMAIN WELL ABOVE NORMAL MONDAY AFTER WITHIN
THE WARM SECTOR.
LONG TERM /MONDAY NIGHT THROUGH SUNDAY/
KEY MESSAGES:
- A COOL-DOWN IS MOST LIKELY MONDAY NIGHT INTO TUESDAY.
- ABOVE AVERAGE TEMPERATURES WEDNESDAY THROUGH FRIDAY.
- POTENTIAL FOR HEAVY RAIN THURSDAY INTO SATURDAY
-------------------------------------------------------------------
DRY AND COOLER CONDITIONS SETTLE IN TUESDAY BEHIND THE COLD
FRONT. BOTH ARE RATHER SHORT-LIVED AS ANOTHER SYSTEM CLIMBS
THROUGH THE UPPER MIDWEST ON WEDNESDAY DRAGGING A WARM FRONT
BACK THROUGH THE REGION. THIS USHERS IN THE RETURN OF ABOVE
NORMAL TEMPERATURES AND RAINFALL.
THERE LOOKS TO BE POTENTIAL FOR A BOUNDARY TO STALL ACROSS THE
OHIO VALLEY BEGINNING LATE-WEEK AND LASTING INTO THE WEEKEND.
THE EXACT PLACEMENT AND ANY FURTHER WOBBLING OF THIS STATIONARY
BOUNDARY WILL BE VERY IMPORTANT TO THE EXPECTED IMPACTS BUT IT
LOOKS LIKELY THAT SOMEWHERE IN THE OH VALLEY IS IN FOR ROUNDS OF
RAINFALL AND THE POSSIBILITY OF HIGH WATER IMPACTS. IT REMAINS
VERY EARLY TO SAY EXACTLY WHERE THESE IMPACTS WILL BE GREATEST
BUT CLUSTERED ANALYSIS. LONG-RANGE ENSEMBLES YIELD SEVERAL DAYS
NEXT WEEK WHERE THE CHANCE TO SEE >1 INCH OF RAINFALL IN 24HRS
IS ABOVE 30% IN OUR REGION. THERE IS ALSO A NOTED 50% CHANCE OF
SOME RIVERS REACHING 'ACTION' STAGE, INCLUDING DOWNTOWN
PITTSBURGH.
AVIATION /03Z MONDAY THROUGH FRIDAY/
A BRIEF PERIOD OF VFR FAVORED UNTIL THE NEXT LINE OF
SHOWERS/STORMS ARRIVES. FKL AND DUJ ARE MORE LIKELY TO STAY
BELOW AT MVFR OR IFR.
THERE'S UNCERTAINTY HOW FAR EAST A LINE OF CONVECTION PROGRESSING
ACROSS OHIO WILL BE ABLE TO HANG-ON WITH THE LACK OF DAYTIME
HEATING. MODEL CONSENSUS IS THAT IT HANGS ON AT LEAST INTO EASTERN
OHIO AFFECTING ZZV WITH HIGHEST CONFIDENCE AND LIKELY AS FAR EAST AS
PIT/AGC. MOST LIKELY TIMING FOR ZZV IS AROUND 03Z, PIT AT 05Z, AND
LBE AT 06Z IF IT HOLDS TOGETHER THAT FAR EAST. INTRODUCED PREVAILING
LOW END MVFR CONDITIONS WITH TEMPO GROUPS FOR IFR TSRA AT ALL SITES
AROUND THE TIMEFRAME OF THE HIGHEST IMPACT. GUSTS ARE LIKELY TO BE
STRONGER AND MORE SPORADIC WITH THE LINE OF CONVECTION.
THE COLD FRONT ITSELF WILL PASS THROUGH MONDAY MORNING WITH PERHAPS
A FEW SHOWERS ACCOMPANYING IT. COLD ADVECTION IN ITS WAKE WILL
REINFORCE LOW CLOUD COVERAGE AND MAINTAIN A 60-80% CHANCE OF MVFR
CIGS INTO THE DAYTIME HOURS ALONG WITH LOCAL RAIN SHOWERS.
THROUGH TOMORROW MORNING, GUSTY WIND WILL CONTINUE WITH 60-80%
PROBABILITIES OF 30 MPH.
OUTLOOK...
VFR RETURNS TUESDAY UNDER HIGH PRESSURE. 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/MLB
NEAR TERM...WM/HEFFERAN/MLB
SHORT TERM...88/AK
LONG TERM...88/AK
AVIATION...MLB/LUPO
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