940
FXUS61 KPBZ 131658
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
1258 PM EDT THU AUG 13 2026
WHAT HAS CHANGED
INCREASED CONFIDENCE FOR THE NEXT WIDESPREAD SEVERE/FLOOD RISK
WITH A CROSSING DISTURBANCE ON SUNDAY.
KEY MESSAGES
1) SCATTERED SHOWERS/STORMS ACROSS EASTERN OHIO AND NORTHERN
WEST VIRGINIA POSE A MARGINAL FLOOD RISK SOUTH/WEST OF
PITTSBURGH EARLY FRIDAY.
3) A BREAK IN ACTIVITY EXPECTED UNTIL THE NEXT FLOOD/SEVERE
CHANCES RETURN SUNDAY.
DISCUSSION
KEY MESSAGE 1...
DRY WEATHER IS EXPECTED UNTIL THE RETURN OF RAIN CHANCES FRIDAY
MORNING. A PUSH OF WARM ADVECTION IN SOUTHWEST LOW-LEVEL FLOW
MAY SLIGHTLY STEEPEN LOW LAPSE RATES INTO FRIDAY MORNING. MOST
ENSEMBLES HAVE CONVECTION FIRING IN THE 03Z TO 06Z WINDOW, BUT
FAVORING POINTS SOUTHWEST OF THE FORECAST AREA. ACCOMPANYING
THIS, EAST OH AND NORTH WV MAY BE ON THE NORTHERN FRINGE OF A
DECAYING MCV THAT MAY INCREASE CONFIDENCE IN CONVECTION
SLIGHTLY.
AROUND 75% TO 90% OF GUIDANCE HAS THE QPF MAXIMA SOUTH OF THIS
REGIONS OH/WV COUNTIES, BUT THERE IS SOME SPATIAL UNCERTAINTY.
IN THE 10% TO 25% CHANCE THIS WARM FRONTAL RAIN SETS UP INTO OUR
AREA, HREF/RRFS MAINTAIN THE OFF CHANCE OF A PATCHY 2" TO 4"
AREA IN STORM TRAINING FRIDAY MORNING. GIVEN THE HIGH CONFIDENCE
IN THE ACTUAL MCV PASSING SOUTH, MORNING ARRIVAL TIME, AND
MOIST ADIABATIC PROFILES, THE SEVERE RISK IS LOW TO NONE. MOST
ENSEMBLES HAVE THE CONDITIONAL, LOW PROBABILITY FLOOD THREAT
WINDOW FROM AROUND 4AM TO NOON AND FAVORING NORTH WV AND
SOUTHEAST OHIO.
KEY MESSAGE 2...
GUIDANCE SUGGESTS A BIT OF A BREAK IN WEATHER THREATS AS A
SURFACE HIGH PRESSURE ATTEMPTS TO PUSH SOUTH FROM ONTARIO, BUT
THIS BREAK WILL BE BRIEF BEFORE MORE SEVERE/FLOOD THREATS
ARRIVE SUNDAY AS THE HIGH PUSHES EAST. ENSEMBLES GENERALLY AGREE
IN AN WEST-EAST SLIDING LOW. THIS AREA MAY SEE A SLOW MOVING
WARM FRONT AHEAD OF THE SYSTEM AND A SLOW DRAGGING COLD FRONT
BEHIND.
THE FLATTER THE FLOW, THE LESS OF A CHANCE FOR ASCENT AND
MINIMIZATION OF ANY THREATS. BUT SHOULD THE UPPER SHORTWAVE
TREND MORE AMPLIFIED, THERE MAY BE MORE ASCENT NEAR THE SURFACE
LOW. THIS WOULD INCREASE EXCESSIVE RAINFALL THREATS ALONG THE
RELATIVELY SLOW PASSING FRONTS AND RAISE CONVECTIVE THREATS IN
THE WARM SECTOR. THE CONDITIONAL FLOOD RISK FAVORS THE WHOLE
AREA WITH A REASONABLE WORST CASE SCENARIO (10% CHANCE) OF A
LOCALIZED AMOUNT SOMEWHERE OF 3 TO 5 INCHES IN A 48HR PERIOD.
THE CONDITIONAL SEVERE THREAT INCREASES FROM NORTH TO SOUTH, AS
DOES THE DISTANCE INTO THE WARM SECTOR. THE PRIMARY THREAT WOULD
APPEAR TO BE DAMAGING WIND AT THIS TIME.
AVIATION /18Z THURSDAY THROUGH TUESDAY/
MOISTURE CONVERGENCE AMID WEAK FLOW HAS SIGNIFICANTLY SLOWED
ANTICIPATED LIFTING/CLEARING OF MVFR CIGS SUCH THAT LATEST HI-
RES GUIDANCE REMAINS OVERLY BULLISH ON IMPROVEMENTS COMPARED TO
SATELLITE TRENDS. WHERE STRATOCU REMAINS, TIMING OF VFR RETURNS
LEANED TOWARD LATER IMPROVEMENTS WITH POTENTIAL FOR FURTHER
DELAYS AT TERMINALS STUCK NEAR THE MIDDLE (BVI/PIT/LBE/AGC).
EVENTUALLY, VFR DEVELOPS WITH INCREASING CIRRUS OVERNIGHT. GLAMP
AND OTHER MOS OUTPUT SUGGESTS ANOTHER ROUND OF EARLY MORNING
FOG/STRATUS, BUT THE LIKELY CIRRUS (WHICH STANDS TO BE FAIRLY
THICK) SHOULD DELAY AND LIMIT ANY POTENTIAL STRATUS/FOG
COVERAGE. AN AREA OF SHOWERS AND LOW PROBABILITY THUNDERSTORMS
WILL CROSS MAINLY SOUTH OF I-70 FRIDAY, THOUGH ONSET TIMING
VARIES FROM EARLY MORNING (06-09Z) TO LATER MORNING (12Z-15Z).
MVFR TO IFR CIGS DEVELOP WITHIN THE HEAVIER SHOWERS AND GRADUAL
TREND HIGHER MOVING NORTH OUT OF THE STRATIFORM RAIN REGION.
OUTLOOK...
AFTER THE MORNING SHOWER/THUNDERSTORM WAVE, SPOTTY SHOWERS (WITH
LOW LIGHTNING PROBABILITY) DEVELOP DURING THE AFTERNOON BEFORE
DISSIPATING THAT EVENING.
OTHERWISE, DRIER WEATHER IS FAVORED UNTIL THE NEXT SYSTEM
CROSSES THE REGION SUNDAY WITH MORE SHOWERS AND THUNDERSTORMS.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...NONE.
OH...NONE.
WV...NONE.
DISCUSSION...MILCAREK
AVIATION...FRAZIER
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