461
FXUS61 KPBZ 131734
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
134 PM EDT SAT JUN 13 2026
WHAT HAS CHANGED
NO MAJOR CHANGES TO SEVERE WEATHER EXPECTATIONS ON SUNDAY, AS
THEY REMAIN DEPENDENT ON MORNING ACTIVITY AND THE RESULTING
AFTERNOON STORM ENVIRONMENT. CONCERN FOR THE POTENTIAL OF
HAZARDOUS WEATHER ON THURSDAY CONTINUES.
KEY MESSAGES
1) POTENTIAL FOR STRONG TO SEVERE THUNDERSTORMS TOMORROW
AFTERNOON AND EVENING WITH A PASSING COLD FRONT
2) QUIET WEATHER EXPECTED MONDAY THROUGH MID-WEEK; MONITORING
POTENTIAL HAZARDOUS WEATHER ON THURSDAY
DISCUSSION
KEY MESSAGE 1...
QUIET WEATHER WILL BE MAINTAINED THROUGH THE AFTERNOON AND
EVENING AS HIGH PRESSURE DEPARTS THE REGION. DAYTIME CUMULUS
WILL COLLAPSE WITH SUNSET, ALTHOUGH MID AND UPPER CLOUDS WILL BE
ON THE INCREASE ON SOUTHWEST FLOW BEHIND THE HIGH.
RAIN CHANCES RETURN VERY LATE TONIGHT IN SOUTHEAST OHIO AND
BEFORE NOON SUNDAY AS A MID-LEVEL SHORTWAVE LIFTS FROM THE
MIDDLE OHIO VALLEY INTO THE REGION BY 18Z. MOST CAMS DO BRING
AT LEAST SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ACROSS THE
REGION WITH THIS INITIAL WAVE, WITH LIFT PROVIDED
ISENTROPICALLY. OUTFLOW FROM OVERNIGHT CONVECTION TO OUR WEST
COULD ALSO PLAY A ROLE IN SUPPORTING INITIATION. THIS ACTIVITY
SHOULD STAY BELOW SEVERE LIMITS. THE MAIN QUESTION BECOMES THE
SHAPE OF THE ENVIRONMENT IN PLACE BEHIND THIS MORNING ACTIVITY.
THIS IS DUE TO THE FOLLOWING MAIN 500MB TROUGH ARRIVAL AND COLD
FRONTAL PASSAGE EXPECTED SUNDAY EVENING. CAMS CONSENSUS IS FOR
A FAIRLY STOUT LINE OF SHOWERS AND THUNDERSTORMS ASSOCIATED WITH
THE FRONT. 0-6KM SHEAR OF 30-40 KNOTS WILL CERTAINLY BE
SUFFICIENT FOR STORM ORGANIZATION. HOWEVER, THE SEVERITY OF
THOSE STORMS WILL BE HIGHLY DEPENDENT ON THE BUOYANCY THAT IS
PRESENT. THE 12Z HREF PRESENTS A VARIETY OF SCENARIOS HERE...FOR
INSTANCE, THE 10TH-90TH PERCENTILE RANGE FOR SURFACE-BASED CAPE
AT 20Z AT PITTSBURGH RANGES FROM ROUGHLY 280 J/KG TO TO 1340
J/KG. THIS PARAMETER WILL LIKELY NOT BE ABLE TO BE ASSESSED
WITH ANY APPRECIABLE CONFIDENCE UNTIL TOMORROW MORNING.
IF THE HIGHER-END CAPE SCENARIOS ARE REALIZED, THE MAIN SEVERE
THREAT APPEARS TO BE DAMAGING WIND GUSTS, GIVEN THE SHEAR/LEVEL
OF STORM ORGANIZATION AND COLD POOL CONSOLIDATION THAT COULD
OCCUR. TORNADOES APPEAR TO BE A SECONDARY THREAT, TIED TO THE
HIGHER-END SCENARIOS WHERE A MORE ROBUST SUPERCELL-LIKE
STRUCTURE CAN TAKE A MORE E OR EVEN ESE DIRECTION, TO THE RIGHT
OF THE MORE ENE MEAN STORM MOTION. HAIL APPEARS LEAST LIKELY OF
THE SEVERE THREATS, AS THE HIGH FREEZING LEVEL AND POOR MID-
LEVEL LAPSE RATES (LESS THAN 6C/KM) LIMIT POTENTIAL. RAIN RATES
WILL ALSO BE HEALTHY GIVEN 1.5-1.7 INCH PRECIPITABLE WATER
VALUES AND WARM CLOUD DEPTHS OF 10-12 THOUSAND FEET. HOWEVER, STORM
MOTION SHOULD BE SUFFICIENT TO MITIGATE ANY FLOODING CONCERNS
OTHER THAN PERHAPS ISOLATED URBAN/POOR DRAINAGE ISSUES.
COLD FRONTAL PASSAGE DURING THE EVENING WILL END THE SEVERE
THREAT FROM WEST TO EAST, WITH THE BOUNDARY CROSSING THE RIDGES
LIKELY IN THE 01Z TO 03Z MONDAY WINDOW.
KEY MESSAGE 2...
IN THE WAKE OF THE SUNDAY COLD FRONT, GENERALLY QUIET WEATHER AND
BELOW-NORMAL TEMPERATURES ARE FORECAST EARLY NEXT WEEK, AS
GREAT LAKES/NORTHEAST CONUS TROUGHING WORKS IN CONCERT WITH
SURFACE HIGH PRESSURE. RAIN CHANCES MAY THEN RETURN TUESDAY
NIGHT/WEDNESDAY AS THE HIGH DEPARTS AND A SHORTWAVE SKIRTS THE
EASTERN GREAT LAKES. MOISTURE AND FLOW APPEAR TO BE WEAK ENOUGH
TO PRECLUDE ANYTHING MORE THAN MINIMAL SEVERE WEATHER CHANCES.
BY THURSDAY, A WARM FRONTAL PASSAGE COULD BRING RISING 500MB HEIGHTS
AND HIGHER DEWPOINTS BACK TO THE REGION. ALONG WITH THIS ARE
INDICATIONS OF ENHANCED FLOW, WITH 45-50 KNOTS AT 700MB AND 70-80
KNOTS AT 500MB ON ENSEMBLE PROGS. THIS COMBINATION SUGGESTS AN
INCREASING RISK OF SEVERE WEATHER ON THIS DAY, ASSOCIATED WITH A
POTENTIAL COLD FRONTAL PASSAGE FROM GREAT LAKES LOW PRESSURE. LONGER-
RANGE MACHINE-LEARNING GUIDANCE FROM NCAR AND CSU AGREE WITH THIS
ASSESSMENT, WITH PROBABILITIES FOR SEVERE WEATHER RANGING FROM 15%
TO 45%. SPC ALSO HAS ALREADY HIGHLIGHTED THURSDAY FOR THE RISK AS
WELL. GIVEN THE INSTABILITY/SHEAR COMBINATION THAT COULD BE
REALIZED, THIS IS A POTENTIALLY VOLATILE SITUATION THAT COULD
PRESENT ALL SEVERE HAZARDS IN HIGHER-END SCENARIOS.
IN ADDITION TO THE SEVERE WEATHER THREAT, MULTIPLE EMBEDDED
SHORTWAVES MAY PROMOTE REPEATED ROUNDS OF PRECIPITATION, RAISING
CONCERNS FOR TRAINING STORMS AND LOCALIZED FLOODING. AT THIS TIME,
THE GREATEST FLOOD RISK APPEARS MORE LIKELY TO FOCUS OVER AREAS JUST
WEST OF THE UPPER OHIO VALLEY. THE EVOLUTION OF THE PATTERN, AND THE
ATTENDANT SEVERE/FLOODING RISKS, WILL NEED TO BE MONITORED CLOSELY
IN THE COMING DAYS.
AVIATION /18Z SATURDAY THROUGH THURSDAY/
VFR EXPECTED WITH A FEW CU THAT DISSIPATE THIS EVENING WHILE
CIRRUS (AND EVENTUALLY LOWER DECKS) ADVANCE AHEAD OF AN INCOMING
SHORTWAVE AND ITS ASSOCIATED CONVECTIVE COMPLEX.
THERE IS A LOW CHANCE NOCTURNAL CONVECTION IN LOWER OHIO RIVER
VALLEY REACHES ZZV PRIOR TO 12Z, BUT HI-RES MODELING GENERALLY
FAVORS A WINDOW BETWEEN 13Z-16Z FOR ANY DECAYING SHOWERS (AND
LOW PROBABILITY THUNDERSTORMS) TO REACH AREA TERMINALS AS IT
WORKS WEST TO EAST.
OUTLOOK...
THERE IS A HIGH PROBABILITY FOR A FAIRLY SOLID LINE OF SHOWERS
AND THUNDERSTORMS TO DEVELOP AHEAD OF A COLD FRONT SUNDAY
AFTERNOON NEAR NE OH TO NW PA, DRIVING SOUTHEAST THROUGH THE
FORECAST REGION THROUGH 02Z SUNDAY NIGHT. AT MINIMUM, USERS CAN
EXPECT HEAVY RAIN WITH GUSTY WINDS BETWEEN 20KTS TO LOCALLY
35KTS IN ANY STORM ALONG WITH MVFR/IFR DIPS TO MVFR/IFR
RESTRICTIONS. PENDING ON THE DEGREE OF HEATING PRIOR TO THE LINE
PASSAGE, STORMS COULD SEE AN ENHANCEMENT OF BOTH LIGHTNING
ACTIVITY AND GUSTY WIND POTENTIAL. OUTSIDE OF THE CONVECTIVE
LINE, MOISTURE CONVERGENCE AHEAD OF THE COLD FRONT MAY RESULT IN
PATCHY MVFR TO IFR CIGS.
DRY ADVECTION AND SUBSIDENCE FAVOR VFR MONDAY INTO TUESDAY
BEFORE THE NEXT POTENTIAL SHORTWAVE SYSTEM ADVANCES THROUGH THE
REGION MID WEEK.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...NONE.
OH...NONE.
WV...NONE.
DISCUSSION...HEFFERAN/CL
AVIATION...FRAZIER
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