135
FXUS61 KPBZ 141845
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
145 PM EST FRI NOV 14 2025
SYNOPSIS
HIGH PRESSURE DEPARTS TODAY, WITH DRY WEATHER INTO TONIGHT.
FAST MOVING LOW PRESSURE CROSSING THE GREAT LAKES TOMORROW WILL
BRING INCREASING WARMTH AND MOISTURE ALONG WITH THE CHANCE OF
SHOWERS AND GUSTY THUNDERSTORMS. BRISK AND COOLER WEATHER IS ON
TAP FOR SUNDAY WITH NORTHWEST-FLOW SHOWERS.
NEAR TERM /THROUGH TONIGHT/
KEY MESSAGES:
- QUIET WEATHER WITH SEASONABLE TEMPERATURES INTO THIS EVENING
WITH DEPARTING HIGH PRESSURE
- FIRST RAINDROPS MAY ARRIVE LATE TONIGHT
---------------------------------------------------------------
WARM ADVECTION ALOFT CONTINUES TO SUPPORT A FAIRLY WIDESPREAD
ALTOCUMULUS DECK ACROSS THE REGION, WHICH IS LIMITING
TEMPERATURE RISES AND PROVIDING A DECENT GRADIENT. AFTERNOON
HIGHS ARE LIKELY TO TOP IN THE MID AND UPPER 40S NORTH OF
PITTSBURGH, AND IN THE 50S NEAR THE CITY AND TO THE SOUTH.
AFTER A PERIOD OF CLEARING THIS EVENING, CLOUDS MAY ONCE AGAIN
THICKEN AND LOWER IN ADVANCE OF AN APPROACHING WARM FRONT AND
UPPER RIDGE. ENOUGH MOISTURE/ISENTROPIC LIFT MAY EXIST AFTER 06Z
FOR THE FIRST DROPS OF LIGHT RAIN TO ARRIVE. A TEMPERATURE
GRADIENT IS LIKELY TO REMAIN, WITH NEAR-FREEZING OVERNIGHT LOWS
NORTH OF I-80 TO VALUES IN THE MID 40S TO THE SOUTH OF I-70.
SHORT TERM /SATURDAY THROUGH SUNDAY/
KEY MESSAGES:
- RAIN CHANCES INCREASE SATURDAY AFTERNOON AND NIGHT
- ISOLATED THUNDERSTORMS WITH GUSTY WIND ARE POSSIBLE SATURDAY
EVENING
- TURNING BLUSTERY AND COLDER SUNDAY, WITH SHOWERS CONTINUING
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THE FLATTENING RIDGE AXIS CROSSES THE UPPER OHIO VALLEY SATURDAY
MORNING, ACCOMPANIED BY THE SURFACE WARM FRONT. INCREASING COLUMN
MOISTURE AND SOME MODEST ISENTROPIC LIFT MAY CONTINUE TO FUEL SOME
PATCHY LIGHT RAIN/SHOWERS THROUGH THE MORNING. THERE ALSO COULD BE A
PERIOD OF SEVERAL HOURS THAT FAVOR AN AREA OF ADVECTION FOG,
PARTICULARLY NORTH OF PITTSBURGH, AS SUGGESTED BY HREF VISIBILITY
PROBABILITIES. THIS WOULD BE IN SPITE OF STRENGTHENING FLOW ALOFT,
ALTHOUGH EVENTUALLY, BY MIDDAY/EARLY AFTERNOON, WIND SHOULD BECOME
STRONG ENOUGH, AND TEMPERATURES WARM ENOUGH, TO LESSEN THE FOG
CONCERN.
ATTENTION THEN TURNS TO THE COLD FRONT WHICH IS SLATED TO CROSS THE
REGION SATURDAY EVENING. A 500MB SHORTWAVE WILL TAKE ON A
NEGATIVE TILT AS IT CROSSES THE UPPER GREAT LAKES SATURDAY
AFTERNOON AND EVENING, HELPING TO PROPEL THE BOUNDARY FORWARD.
CAMS DO SHOW SHOWER DEVELOPMENT ALONG AND AHEAD OF THE BOUNDARY,
BUT THE POTENTIAL FOR DEEP CONVECTION STILL REMAINS
QUESTIONABLE. AFTER WEAKENING A BIT IN THE MORNING, 0-6KM BULK
SHEAR INCREASES INTO THE 45 TO 55 KNOT RANGE DURING THE
AFTERNOON AND EVENING. INSTABILITY REMAINS THE LIMITING FACTOR.
A WARM LAYER ALOFT REMAINS PRESENT ON MODEL SOUNDINGS, LIMITING
CAPE (HREF PROBS OF 200 J/KG GENERALLY 50 PERCENT OR LESS FROM
6PM TO MIDNIGHT), AND LAPSE RATES ALOFT REMAIN POOR. SUPPORT FOR
LIFT TO OVERCOME THE INHIBITION REMAINS UNCERTAIN. A 250MB JET
WILL BE NOSING INTO THE OHIO VALLEY ON SATURDAY, BUT TIMING OF
BEST UPPER DIVERGENCE IN FAVORED QUADRANTS IS NOT CLEAR. STILL,
IF EVAPORATIVE COOLING ALOFT CAN SHARPEN LAPSE RATES AT LEAST ON
A LOCALIZED BASIS, SOME LOW POTENTIAL FOR DOWNWARD TRANSPORT OF
40-50 KNOT FLOW TO THE SURFACE REMAINS. THE SPC DAY 2 MARGINAL
SEVERE RISK FOR WIND GUSTS IS REASONABLE. AWAY FROM
SHOWERS/CONVECTION, EVEN MODEST MIXING WILL ALLOW BACKGROUND
WIND GUSTS INTO THE 20 TO 25 KNOT RANGE. GIVEN THE SHEAR AND
COLD AIR ALOFT, SOME SMALL, GRAUPEL-LIKE HAIL COULD BE POSSIBLE
IN A FEW CASES AS WELL.
NORTHWEST-FLOW SHOWERS SHOULD CONTINUE BEHIND THE FRONT THROUGH
SATURDAY NIGHT INTO SUNDAY, EVENTUALLY BECOMING MAINLY
CONCENTRATED TO AREAS NORTH OF US-422 THANKS TO LAKE
ENHANCEMENT. 850MB TEMPERATURES FALLING TO SUBZERO VALUES WILL
ALLOW A MIX WITH, AND AND EVENTUAL CHANGE TO SNOW BY 00Z MONDAY,
WITH ANY ACCUMULATION OF NOTE LIKELY HOLDING OFF UNTIL AFTER
SUNSET. A STILL-DECENT SURFACE PRESSURE GRADIENT AND BETTER
LOW- LEVEL LAPSE RATES ON SUNDAY SHOULD ALLOW FOR MORE
EFFICIENT MIXING, WITH WIDESPREAD WIND GUSTS TO 30 KNOTS. THE
LAURELS OF COURSE WILL LIKELY REACH HIGHER PEAKS BETWEEN 30 AND
40 KNOTS. A WIND ADVISORY MAY EVENTUALLY BE NEEDED FOR EASTERN
TUCKER COUNTY; NBM PROBABILITIES OF MAX GUSTS GREATER THAN 45
MPH ARE IN THE 75 TO 95 PERCENT RANGE.
LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/
KEY MESSAGES:
- POTENTIAL LAKE EFFECT SNOW BAND LATE SUNDAY INTO MONDAY IN
NORTHWEST PA
- ACTIVE WEATHER PATTERN CONTINUES, FAVORING SEASONABLY COOL
TEMPERATURE
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BY SUNDAY AFTERNOON/EVENING, COLD ADVECTION IN NORTHWEST FLOW
PLUS WEAK VORTICITY ADVECTION WILL BEGIN TO AID DEVELOPMENT OF A
LAKE EFFECT BAND OVER A NARROW SWATH OF NORTHWEST PA THAT WILL
SLOWLY TAPER OFF INTO MONDAY. THE KEY TRENDS BOTH IN GLOBAL AND
INITIAL HI-RES MODEL RUNS SUGGEST SLIGHTLY COOLER 850MB TEMPS
(INCHING TOWARD -8 DEGREES C) WITH SUBTLE WIND ANGLE CHANGES
THAT MAY CREATE A MOISTURE FETCH FROM LAKE SUPERIOR THROUGH LAKE
ERIE. IF THIS OCCURS, A NARROW PORTION OF
VENANGO/FOREST/CLARION/JEFFERSON COUNTIES COULD SEE SNOWFALL
ACCUMULATIONS APPROACH/EXCEED WARNING CRITERIA (6+) INCHES.
CONFIDENCE REMAINS LOW WITHOUT MORE HIGHER-RESOLUTION DATA AS
WELL AS POTENTIAL VARIANCES IN THE SNOW BAND AXIS, BUT
HIGHLIGHTED THIS REGION FOR POTENTIAL SNOW HEADLINES THROUGH THE
DAY MONDAY.
OTHERWISE, COLD NORTHWEST FLOW WITH HIGH PRESSURE TO THE WEST
WILL SUPPORT DRYING CONDITIONS ACROSS THE REGION LATE SUNDAY
INTO MONDAY AS AREA TEMPERATURE FALLS BACK BELOW NORMAL. RESIDUAL
PRESSURE GRADIENTS AND MIXING SUPPORT PERIODS OF 25-35MPH GUSTS
THROUGH MONDAY IN THE LOWLANDS, WITH POTENTIAL ADVISORY LEVEL
GUSTS IN THE HIGHEST TERRAIN OF EASTERN TUCKER COUNTY. AGAIN, IF
CONFIDENCE INCREASES ON THIS OCCURRENCE, WIND HEADLINES MAY BE
NEEDED.
THE ACTIVE WEATHER PATTERN CONTINUES TUESDAY AS LINGERING
TROUGHING OVER THE EASTERN CONUS SEES A FAST-MOVING EMBEDDED
SHORTWAVE DIP SOUTH OF THE REGION THAT WILL CREATE ADDITIONAL
PRECIPITATION CHANCES FAVORING SOUTH OF PITTSBURGH (CURRENT
THERMAL PROFILES LENDS TO RAIN WITH ANY SNOW STRUGGLING TO
ACCUMULATE). THEREAFTER, LONG RANGE ENSEMBLE MODELS SHOW
INCREASING VARIANCE WITH PLACEMENT OF UPPER RIDGING, SUGGESTING
IT EITHER EDGES EAST (FOSTERING WARMING TREND AND BRIEF DRY
PERIOD) OR REMAINS OVER CENTRAL CONUS (MAINTAIN COOL WEATHER
WITH INTERMITTENT BUT LOW ACCUMULATION PRECIPITATION).
AVIATION /18Z FRIDAY THROUGH WEDNESDAY/
VFR CONDITIONS ARE FORECAST THROUGH TONIGHT. MID-LEVEL CLOUDS
WILL CONTINUE TO CROSS WITH A DISTURBANCE ALOFT AND WARM
ADVECTION IN NORTHWEST FLOW. THE LOWER LEVELS REMAIN FAIRLY DRY
OVERALL. CEILINGS ABOVE 8KFT ARE FORECAST, WITH SOME PARTIAL
CLEARING EXPECTED TONIGHT. WITH A WEAKER PRESSURE GRADIENT AS
COMPARED TO YESTERDAY, SOUTHWEST WIND IS ONLY FORECAST TO REACH
THE 10 TO 15 KNOT RANGE IN GUSTS THIS AFTERNOON.
CLOUDS SHOULD THICKEN AND LOWER TONIGHT WITH AN APPROACHING
WARM FRONT. A FEW, NON-RESTRICTIVE LIGHT RAIN SHOWERS MAY BEGIN
TO ARRIVE AFTER 06Z AND SPREAD NORTH THROUGH THE MORNING. WITH A
CROSSING WARM FRONT BRINGING A LOW-LEVEL MOISTURE PUSH, MODEL
SOUNDINGS ARE SUGGESTING THE DEVELOPMENT OF ADVECTION FOG
BEGINNING AROUND SUNRISE AND OVERSPREADING SOME AREAS NEAR AND
TO THE NORTH OF PIT. PROBABILITIES OF MVFR CEILINGS BEGIN TO
SPIKE ABOVE 80 PERCENT AFTER 09Z OR SO, MAINLY SOUTH OF I-70,
BEFORE OVERSPREADING OTHER TERMINALS DURING THE REST OF THE
MORNING. IFR VISIBILITY PROBABILITIES ARE HIGHEST (ABOVE 50
PERCENT) IN THE I-80 CORRIDOR FROM MID-MORNING INTO EARLY
AFTERNOON. THUS, AT FKL/DUJ, PREVAILING IFR CEILING/VISIBILITY
WAS INTRODUCED AT THE TAIL END OF THE NEW TAF SET FOR FOG AND
POTENTIAL DRIZZLE. THE SOUTHERN EXTENT OF THESE RESTRICTIONS
REMAINS A BIT UNCERTAIN, AND PROB30S WERE USED FOR POTENTIAL
IMPACTS AT BVI, PIT, AGC, AND LBE. HLG, ZZV, AND MGW WERE LEFT
OUT OF THIS FOR NOW. SOUTHWEST WIND WILL BEGIN TO PICK UP AFTER
SUNRISE, WITH SOME ISOLATED GUSTS TO 20 KNOTS POSSIBLE,
PARTICULARLY SOUTH OF PIT.
OUTLOOK...
RESTRICTIONS SHOULD BECOME MORE WIDESPREAD AS SATURDAY
PROGRESSES, WITH BETTER CHANCE FOR SHOWERS AND ELEVATED WIND
GUSTS SATURDAY AFTERNOON AND EVENING ALONG A COLD FRONT. LAKE-
ENHANCED PRECIPITATION IS EXPECTED BEHIND THE FRONT ON SUNDAY
WITH THE TYPICAL SCATTERED NATURE.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...NONE.
OH...NONE.
WV...NONE.
SYNOPSIS...FRAZIER/CL
NEAR TERM...CL
SHORT TERM...CL
LONG TERM...FRAZIER
AVIATION...CL
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