016
FXUS61 KPBZ 201641
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
1241 PM EDT MON OCT 20 2025
SYNOPSIS
A BRIEF VISIT BY HIGH PRESSURE BRINGS DRY WEATHER AND SEASONABLE
TEMPERATURES THROUGH TONIGHT. A FEW ROUNDS OF SHOWERS ARE
EXPECTED TUESDAY THROUGH THURSDAY COURTESY OF UPPER LEVEL LOW
PRESSURE, WITH COOL AND BLUSTERY CONDITIONS EXPECTED BY
MIDWEEK.
NEAR TERM /THROUGH TONIGHT/
KEY MESSAGES:
- DRY WEATHER THROUGH TONIGHT WITH SKIES BECOMING MOSTLY CLEAR
- TEMPERATURES CLOSE TO SEASONABLE LEVELS
---------------------------------------------------------------
THE REMNANTS OF A STUBBORN LAKE-ENHANCED BAND OF SHOWERS WILL
CONTINUE TO DISSIPATE THROUGH MIDDAY AS SURFACE AND MID-LEVEL
RIDGING BUILD INTO THE UPPER OHIO VALLEY. CUMULUS/STRATOCUMULUS
ARE PERSISTING MAINLY NORTH OF I-70 DUE TO THE NORTHWESTERLY
FLOW. LATER TODAY, BACKING LOW-LEVEL FLOW WILL BRING IN A DRIER
AIR MASS, WHILE ALSO CUTTING OFF THE LAKE INFLUENCE AND LEADING
TO A MOSTLY CLEAR SKY BY EVENING. WIND GUSTS OF 20 TO 30 MPH
WILL ALSO EASE BY SUNSET AS MIXING DIURNALLY DECREASES AND AS
THE SURFACE PRESSURE GRADIENT RELAXES. AFTERNOON HIGHS TOPPING
OUT IN THE 50S REPRESENT VALUES JUST A TOUCH BELOW SEASONAL
NORMS.
CLEAR SKIES CONTINUE INTO THE OVERNIGHT HOURS AS THE RIDGE AXIS
PASSES, BUT MID AND UPPER CLOUDS SHOULD GET TO AT LEAST EASTERN
OHIO BY 12Z AS THE NEXT SHORTWAVE TROUGH REACHES THE GREAT
LAKES. WIND SHOULD BRIEFLY GO LIGHT TONIGHT, BUT THEN PICK UP A
BIT TOWARDS DAWN AS THE PRESSURE GRADIENT BEGINS TO TIGHTEN ONCE
AGAIN. LOW TEMPERATURES WILL BE SEASONABLY COOL. ALTHOUGH A FEW
LOCATIONS NORTHEAST OF PITTSBURGH MAY DROP INTO THE MID 30S,
ANY FROST SHOULD BE LIMITED AND PATCHY AT MOST DUE TO THE
INCREASE IN WIND LATE TONIGHT.
SHORT TERM /TUESDAY THROUGH THURSDAY NIGHT/
KEY MESSAGES:
- MULTIPLE ROUNDS OF RAIN SHOWERS TUESDAY INTO WEDNESDAY MORNING
- PROLONGED PERIOD OF BELOW NORMAL TEMPERATURE AND LAKE ENHANCED
SHOWER ACTIVITY
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A DEEP UPPER LEVEL TROUGH OVER THE UPPER MISSISSIPPI RIVER
VALLEY WILL SLIDE OVER THE NORTHERN GREAT LAKES TUESDAY AS AN
INITIAL SHORTWAVE ROUNDING ITS BASES PUSHES THROUGH AN INITIAL
COLD FRONTAL BOUNDARY. THOUGH LIFT ALONG THE BOUNDARY WILL BE
STRONG, MEAGER MOISTURE RETURNS IN SOUTHERLY FLOW AHEAD OF THE
FRONT LIKELY FAVORS A MORE NARROW LINE OF EAST-MOVING SHOWERS
BETWEEN 8AM THROUGH 2PM. THESE LOW-TOPPED SHOWERS ARE UNLIKELY
TO DEVELOP LIGHTNING, BUT MAY FEATURE A BRIEF ENHANCEMENT OF THE
BROADER SYNOPTIC 20-30MPH WIND (40-50% PROBABILITY OF GUST
BETWEEN 35-40MPH). A BRIEF PERIOD AFTER ITS PASSAGE SHOULD
FEATURE DRY WEATHER AND THE LAST BIT OF SEASONABLE TEMPERATURE
EVEN AS COLD ADVECTION BEGINS.
THEREAFTER, GRADUAL COLD ADVECTION THAT DROP AREA TEMPERATURE
5-10 DEGREES BELOW THE DAILY AVERAGE PLUS MORE SHORTWAVE
MOVEMENT AROUND THE CLOSED UPPER LOW WILL OFFER ADDITIONAL
ROUNDS OF SHOWERS LATE TUESDAY AFTERNOON INTO WEDNESDAY MORNING
AREAWIDE. DRY SLOTTING AROUND THE UPPER LOW FAVORS DISSIPATING
RAIN CHANCES FOR LOCATIONS SOUTH OF I-80 THROUGH THURSDAY
MORNING; NORTH OF I-80, THERE WILL BE BANDS OF LAKE EFFECT RAIN
SHOWERS CAUSED BY LARGE VARIATION IN LAKE TEMPERATURE (CURRENTLY
AROUND NEAR 18 DEGREES C) TO 850MB TEMP (NEAR 0 DEGREES C).
SOME SUBTLE VARIATION IN 850MB FLOW DIRECTION EXISTS, BUT
ENSEMBLE MEANS FAVOR A MOSTLY WSW 850MB FLOW THAT WOULD KEEP A
MAJORITY OF SHOWERS TO THE NORTHERN TIER OF FORECAST COUNTIES.
THERE MAY BE ONE LAST SHORTWAVE SURGE SOUTHEAST THURSDAY AS THE
UPPER TROUGH BEGINS EXITING TOWARD NEW ENGLAND THAT MAY OFFER
LOW PROBABILITY LIGHT RAIN SHOWERS TO MOST LOCATIONS THROUGH THE
DAY. OTHERWISE, HEIGHT RISES AND BUILDING SURFACE HIGH PRESSURE
BY THURSDAY EVENING WILL END PRECIPITATION CHANCES FOR ALL
LOCATIONS.
LONG TERM /FRIDAY THROUGH SUNDAY/
KEY MESSAGES:
- DRY WEATHER AND TEMPERATURE MODERATION FAVORED FRIDAY/SATURDAY
- WIDESPREAD PRECIPITATION CHANCES RETURN SUNDAY
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ENSEMBLE MODEL GUIDANCE FAVORS BROAD HEIGHT RISES WITHIN
WESTERLY FLOW AS SURFACE HIGH PRESSURE SLOWLY CROSSES THE
REGION. TEMPERATURE WILL MODERATE TOWARD SEASONAL AVERAGES WHILE
PRECIPITATION SHOULD REMAIN SOUTHEAST OF THE REGION.
VARIABILITY GROWS THEREAFTER AS MODELS ARE SCATTERED IN
RESOLVING THE PROGRESSION OF A CUT-OFF LOW ATTEMPTING TO LIFT
OUT OF THE TX PANHANDLE AND ITS INTERACTION WITH A NEW ENGLAND
TROUGH OF VARYING DEPTH. THE MOST THAT CAN BE SAID IS THAT THE
FAVORED SCENARIOS WOULD BRING THE NEXT ROUND OF RAIN SUNDAY INTO
EARLY NEXT WEEK WITH NEAR NORMAL TEMPERATURE.
AVIATION /18Z MONDAY THROUGH SATURDAY/
STRATOCUMULUS (GENERALLY MVFR TO VFR) CONTINUES TO LINGER AT
12Z IN NORTHWEST FLOW OFF OF LAKE ERIE, WITH A FEW ISOLATED RAIN
SHOWERS. THIS REGIME WILL NOT LAST MUCH LONGER THOUGH. AS A
MID-LEVEL TROUGH AXIS CONTINUES OFF TO THE EAST AND GREAT LAKES
RIDGING STARTS TO BUILD INTO THE UPPER OHIO VALLEY, LOW-LEVEL
FLOW IS IN THE PROCESS OF VEERING TO THE W/SW, AND DRIER AIR IS
STARTING TO BUILD IN. THIS WILL LEAD TO AREAWIDE VFR CONDITIONS
BY LATE MORNING, ALTHOUGH A BROKEN DECK LIKELY WILL LINGER NORTH
OF PIT INTO THE AFTERNOON. WSW WIND WILL CONTINUE TO GUST INTO
THE 20 TO 25 KNOT RANGE THROUGH THE DAY AS LOW-LEVEL LAPSE RATES
DIURNALLY STEEPEN.
A MOSTLY CLEAR SKY IS FORECAST FOR MUCH OF THE NIGHT AS THE
RIDGE CROSSES, ALTHOUGH SOME MID AND UPPER CLOUD MAY BEGIN TO
SHOW UP TOWARDS SUNRISE AHEAD OF THE NEXT SHORTWAVE TROUGH.
WIND WILL DIMINISH THIS EVENING AND REMAIN LIGHT SOUTHERLY INTO
THE OVERNIGHT. WIND MAY FRESHEN A BIT TOWARDS 10 KNOTS OR SO
TOWARDS 12Z.
OUTLOOK
HIGH PRESSURE WILL LIKELY MAINTAIN VFR CONDITIONS THROUGH
TUESDAY BEFORE PERIODIC RESTRICTION AND RAIN CHANCES RETURN
TUESDAY NIGHT THROUGH MID WEEK AS A SERIES OF SHORTWAVE TROUGHS
CROSS THE AREA. DAYTIME WINDS MAY CONTINUE TO BE BREEZY THROUGH
AT LEAST MID WEEK AS PROBABILITIES FOR GUSTS EXCEEDING 20 KTS
REMAIN HIGH (>60% CHANCE) EACH AFTERNOON THROUGH WEDNESDAY.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...NONE.
OH...NONE.
WV...NONE.
SYNOPSIS...CL
NEAR TERM...CL
SHORT TERM...FRAZIER
LONG TERM...FRAZIER
AVIATION...CL
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