446
FXUS61 KPBZ 111926
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
326 PM EDT SUN OCT 11 2026
WHAT HAS CHANGED
FLOODING RISKS WANE THIS EVENING AS RAIN FROM ISAIAS DEPARTS.
THE NEXT LARGE CHANCE FOR IMPACTFUL WEATHER COMES LATE-WEEK VIA
A STRONG LOW PRESSURE SYSTEM THAT MAY BRING RAIN, WINDS, AND
COOLER WEATHER.
KEY MESSAGES
1) ISAIAS WILL CONTINUE ITS DEPARTURE THROUGH TONIGHT.
2) RAIN CHANCES RETURN MID-WEEK; IMPACTFUL WEATHER IS POSSIBLE
FRIDAY/SATURDAY WITH A STRONG LOW PRESSURE SYSTEM.
DISCUSSION
KEY MESSAGE 1...
ISAIAS WILL CONTINUE TO MOVE EAST INTO TONIGHT. PRECIPITATION
AND GUSTY WINDS WILL SUBSIDE AS GENERALIZED ASCENT AND GRADIENT
WINDS MOVE WITH IT. PRECIPITATION CHANCES WILL LAST THE LONGEST
SOUTHEAST OF PITTSBURGH INTO THE HIGH TERRAIN WITH OROGRAPHIC
LIFT AND GREATEST PROXIMITY TO COASTAL LOW DEVELOPMENT, BUT
MEDIAN 24 RAIN THROUGH 2PM MONDAY SITS ONLY AROUND AN ADDITIONAL
0.1 TO 0.3 INCHES WITH A WORST-SCAE SCENARIO BULLS-EYE OF 1.5"
SHOULD SHOWERS FORM TONIGHT. EVEN THIS WOULD LIKELY NOT LEAD TO ANY
ADDITIONAL FLOOD CONCERNS. AS FOR WIND, GUSTS UP TO 30-40MPH IN HIGH
TERRAIN THIS AFTERNOON WILL CALM TO LIGHT NORTHWEST WINDS TONIGHT,
SO NO ADDITIONAL CONCERNS THERE AS WELL.
KEY MESSAGE 2...
INTO MID-WEEK, THE 500MB PATTERN TRENDS MORE TOWARDS A WESTERN
TROUGH AND AN EASTERN RIDGE, WHICH WILL ACTUALLY PUSH
TEMPERATURES CLOSE TO 15 DEGREES ABOVE NORMAL TUESDAY. A LOW
PASSING TO THE NORTH WILL ACCELERATE GRADIENT LOW-LEVEL FLOW
TUESDAY, THOUGH LREF KEEPS A 90% CHANCE OF SBCAPE >500, AND A
50% CHANCE OF VALUES NEAR 0. SPC HAS HOISTED A DAY-3 MARGINAL
RISK IN NORTH CENTRAL PA FOR NOW WHERE SHEAR IS MAXIMIZED (NEAR
40KTS), WITH DAMAGING WIND AS THE PRIMARY THREAT.
BETTER RAIN CHANCES ARRIVE INTO WEDNESDAY AS A WEAK SHORTWAVE
MOVES THROUGH, WITH QPF TOTALS ANYWHERE FROM A LIGHT
ACCUMULATION TO 0.50" (NBM 25TH-90TH), SHOULD THE SHORTWAVE
MATERIALIZE.
THE BIG QUESTION THEN BECOMES WHAT WILL HAPPEN WITH A LATE-WEEK
SYSTEM, OF WHICH, ENSEMBLES ARE STILL HIGHLY UNCERTAIN. THE MAIN
DRIVER OF UNCERTAINTY IS THE TIMING AND PLACEMENT OF A DIGGING
EASTERN TOUGH. IN SCENARIO 1, THE TROUGH DIGS EAST OF THE AREA
SOMETIME THURSDAY THRU SATURDAY. IN THIS SCENARIO, THE AREA
WOULD BE WARMER THAN ENSEMBLE MEANS AND LESS UNSETTLED. IN
SCENARIO 2, THE TROUGH BARRELS DOWN DIRECTLY INTO THE AREA WITH
A STRONG COLD FRONT (FAVORED FRIDAY INTO SATURDAY) AND
POTENTIALLY BRING SOME RAIN, WINDS (APPROACHING ADVISORY
CRITERIA, AT MINIMUM), AND EVEN LAKE- ENHANCED SNOW/RAIN SHOWER
POTENTIAL INTO SATURDAY. IN SCENARIO 3, THE TROUGH MAY DROP TO
INTO THE MIDWEST SOMETIME FRIDAY/SATURDAY WITH RAIN AHEAD OF IT,
AND BRING A LONGER PERIOD OF COOL AND WINDY CONDITIONS AS THE
UPPER LOW STRUGGLES TO REJOIN THE FLOW INTO NEXT WEEKEND. IF
TRULY MAXIMIZED, SCENARIO 2 WOULD BE THE MOST IMPACTFUL DUE TO
WIND GUSTS RISKS AND LAKE EFFECT SNOW POTENTIAL (2-10%
PROBABILITY FOR LOCATIONS TO SEE >= 3" OF SNOW).
AVIATION /19Z SUNDAY THROUGH FRIDAY/
AS THE REMNANTS OF ISAIAS CONTINUE EASTWARD, THE EASTERLY WIND
WILL EASE AS IT SHIFTS OUT OF THE NORTHEAST BY THIS EVENING. BY
TOMORROW MORNING, THE WIND WILL COME OUT OF THE NORTHWEST WITH
SPEEDS AROUND 5KTS THROUGHOUT THE DAY.
RESIDUAL MOISTURE WITHIN THE BOUNDARY LAYER ALONG WITH THE
EASING WIND WILL LIKELY KEEP CIGS LOW (MVFR TO IFR) INTO EARLY
MONDAY MORNING DESPITE DECREASING RAIN CHANCES. TOMORROW
MORNING, CEILINGS WILL BEGIN TO GRADUALLY LIFT STARTING IN THE
WEST. BY TOMORROW EVENING, ALL PORTS SHOULD BE VFR.
OUTLOOK...
VFR CONDITIONS ARE EXPECTED BY MONDAY AFTERNOON WITH WARM,
SOUTHWEST FLOW DISSIPATING ANY LINGERING LOW-LEVEL CIGS.
A COLD FRONT MAY RETURN RESTRICTIONS LATE TUESDAY.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...NONE.
OH...NONE.
WV...NONE.
DISCUSSION...MILCAREK
AVIATION...LUPO
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