059
FXUS61 KPBZ 152341
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
641 PM EST THU JAN 15 2026
WHAT HAS CHANGED
DEVELOPMENT OF A HEAVIER LAKE EFFECT BAND NEAR AND ALONG I-80
CAUSING CONFIRMED TRAVEL IMPACTS LED TO EXPANSION OF WINTER
WEATHER ADVISORY INTO CLARION AND JEFFERSON COUNTIES IN
NORTHWEST PA. ACCUMULATING SNOW IS LIKELY AGAIN FRIDAY INTO
SATURDAY, WITH PERIODIC SNOW CHANCES THROUGH NEXT WEEK. WIND
CHILLS HAVE LOWERED FURTHER WITH VERY COLD TEMPERATURES EARLY
NEXT WEEK. COLD WEATHER ADVISORIES MAY BE NEEDED FOR SOME AREAS.
KEY MESSAGES
1) LAKE ENHANCED BANDS AND SHOWERS THIS AFTERNOON. COLD TEMPERATURES
OVERNIGHT WITH A COLD WEATHER ADVISORY CONTINUES FOR E'RN TUCKER COUNTY.
2) ACCUMULATING SNOW LATE FRIDAY AND SATURDAY WITH LOWER
PROBABILITIES FOR REACHING HEADLINE CRITERIA.
3) LIGHT SNOW CHANCES ACCOMPANY NEAR COLD WEATHER ADVISORY WIND
CHILLS FOR THE START OF NEXT WEEK.
DISCUSSION
KEY MESSAGE 1...
THE BOUNDARY LAYER FLOW INDICATES ENHANCEMENT FROM LAKE ERIE, WITH
AN ADDITIONAL CONNECTION TO LAKE HURON, MAINLY IMPACTING NW PA. THIS
HAS LED TO ONE BAND DEVELOPING NEAR I-80 THAT HAS CAUSED CONFIRMED
TRAVEL IMPACTS FROM SLICK ROADS WHICH IS LIKELY TO BE PERSISTENT
THROUGH THE AFTERNOON. EXPECT TOTAL ACCUMULATIONS BY THE END OF THE
DAY FROM 2 TO 5 INCHES (LOCALLY HIGHER IF THERE IS STATIONARY
BANDING FOR MULTIPLE HOURS) NEAR AND NORTH OF THE I-80 CORRIDOR AS
WELL AS IN THE HIGHER TERRAIN WHERE UPSLOPING IS EXPECTED WITH WNW
WIND . THE FLOW OFF THE LAKE HAS ALSO IMPROVED INSTABILITY IN
WESTERN PA ALLOWING FOR POPCORN SNOW SHOWERS TO DEVELOP. THE SNOW
SHOULD TAPER OFF LATE THIS AFTERNOON AND EVENING AS THE UPPER-LEVEL
LOW MOVES EAST, FLOW FROM THE LAKES CUTS-OFF, AND DRYING OCCURS IN
THE DENDRITIC GROWTH ZONE.
TONIGHT, TEMPERATURES ARE EXPECTED TO DROP INTO THE MID-TEENS FOR
MOST OF THE AREA. A COLD WEATHER ADVISORY FOR EASTERN TUCKER COUNTY
WV WAS MAINTAINED WHERE COLD TEMPERATURES (7F-12F) AND WIND GUSTS UP
TO 50 MPH IS FORECAST TO PRODUCE WIND CHILLS AROUND -15F.
KEY MESSAGE 2...
ENSEMBLE MODEL TRENDS FAVOR THE DEVELOPMENT OF A SLOWLY
DEEPENING UPPER TROUGH THAT GENERALLY SITS OVER THE LOWER OHIO
RIVER VALLEY THROUGH THE WEEKEND WHILE EMBEDDED SHORTWAVES LIFT
NE THROUGH THE REGION. THESE WAVES WILL PROVIDE ROUNDS OF
PRECIPITATION (MAINLY SNOW) STARTING FRIDAY AFTERNOON INTO EARLY
SUNDAY MORNING RESULTING IN AREAWIDE ACCUMULATIONS. CROSSING OF
THE UPPER TROUGH AXIS VARIES IN TIMING BETWEEN LATE SUNDAY INTO
EARLY NEXT WEEK, BUT THE MORE LIKELY ROUTE KEEPS IT NORTH OF THE
REGION AND LIMITS SNOW POTENTIAL BY SUNDAY EVENING.
GRADUAL ACCUMULATIONS ARE FAVORED DURING THE FRIDAY-SATURDAY
PERIOD DUE TO A COMBINATION OF WEAKER ASCENT/LIMITED SURFACE
FORCING, MODEST 700MB WARMING THAT REDUCES SLRS (ALONG WITH
SOME SURFACE WARM ADVECTION NEAR/SOUTHWEST OF PITTSBURGH PUSHING
SURFACE TEMPERATURES ABOVE FREEZING), AND WESTERLY FLOW THAT
PREVENTS/LIMITS LAKE ENHANCEMENT. AS A RESULT, THE PROBABILITY
FOR EXCEEDING 3" OVER A 24-HOUR PERIOD IS LOW AND ONLY PEAKS
BETWEEN 30-50% (MAINLY OVER WV HIGHER TERRAIN) FOR THE LATE
FRIDAY TO SATURDAY AFTERNOON PERIOD, LIMITING POTENTIAL NEED FOR
WINTER HEADLINES. THOUGH MORE LIKELY OUTCOME IS A HALF INCH TO
INCH HERE, ANOTHER INCH THERE OVER THE COURSE OF 48 HOURS TO END
UP IN THE 1 TO 3" (WITH LOCALLY HIGHER) RANGE BY SUNDAY.
KEY MESSAGE 3...
THOUGH TIMING OF UPPER TROUGH PASSAGE AND DEPTH IS UNCERTAINTY
FOR THE EARLY WEEK PERIOD, CONFIDENCE IS HIGH FOR A COLD AIR
MASS TO MOVE INTO THE UPPER OHIO RIVER VALLEY BY SUNDAY AND
REMAINS IN PLACE THROUGH THE MIDDLE OF NEXT WEEK. THE
COMBINATION OF THE WELL BELOW NORMAL TEMPERATURE AND PERIODS OF
GUSTY WIND IS LIKELY TO RESULT IN MULTIPLE PERIODS WITH SINGLE
DIGIT TO BELOW ZERO WIND CHILLS. PROBABILITIES ARE HIGHEST FOR
POTENTIAL COLD WEATHER ADVISORY CRITERIA WIND CHILLS BEING
ACHIEVED LATE MONDAY INTO TUESDAY MORNING,
SNOW CHANCES GENERALLY APPEAR LIMITED DURING THIS PERIOD, BUT
ALTERATIONS IN TROUGH DEPTH COULD INTRODUCE GREATER INFLUENCE OF
LAKE EFFECT SNOW DOWN INTO PORTIONS OF WESTERN PA COMPARED TO
THE FAVORED ALIGNMENT OF ALONG THE LAKE ERIE SHORES.
AVIATION /00Z FRIDAY THROUGH TUESDAY/
KEY MESSAGES...
1) IMPROVING CIG AND VIS RESTRICTIONS WITH SCATTERING AND A
TEMPORARY DEPARTURE OF SNOW.
2) GUSTS TOMORROW AFTERNOON MAY DEVELOP INTO SHEAR OVERNIGHT
WITH INCREASING CHANCES OF SNOW AFTER SUNSET.
------------------------------------------------------------
ALL SITES ARE CURRENTLY OBSERVING VFR/MVFR CIGS WITH VIS
SPANNING FROM VFR TO IFR AT FKL/DUJ WITH HIGHER PRESENCE OF
SNOW. INTO TONIGHT, CLOUDS ARE EXPECTED TO SCATTER FROM THE
SOUTHWEST. CHANCES OF AT LEAST MVFR CIGS AND IFR VIS HOLD ON
LONGER AT FKL AND DUJ WITH LAKE INFLUENCE BEFORE WINDS BACK
OVERNIGHT.
BY MORNING, ALL SITES HAVE A >70% CHANCE OF VFR WITH FLOW
PRIMARILY SOUTH TO SOUTHWEST. GUSTS MAY PICK UP AGAIN IN THE
AFTERNOON AS CIGS FILL IN AND LOWER AGAIN AHEAD OF THE NEXT
DISTURBANCE. CHANCES OF SNOW INCREASE TOWARDS THE END OF THE
PERIOD, THOUGH ADDITIONAL FLAKES MAY BE CHALLENGED BY DRY AIR IN
PLACE. THERE IS A 30% CHANCE OF AFTERNOON SNOW AT FKL/DUJ AND
EVENING SNOW ELSEWHERE, BEFORE CHANCES INCREASE >50% OVERNIGHT
WITH VIS AND CIG RESTRICTIONS POSSIBLE. DECOUPLING MAY ALSO LEAD
TO A BRIEF BOUT OF SHEAR IN THE EARLY OVERNIGHT PERIOD.
OUTLOOK...
NBM CHANCES OF AT LEAST MVFR CIGS/VIS DO NOT OVERSPEND THE AREA
WITH >50% PROBABILITY UNTIL 03Z TO 07Z SATURDAY. CHANCES OF IFR
CIGS ARE ONLY 40% LIKELY FOR NOW, BUT CHANCES OF IFR IN SNOW ARE
HIGHER. RESTRICTIONS LIKELY LIFT SATURDAY NIGHT.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR
PAZ007>009-015-016.
OH...NONE.
WV...COLD WEATHER ADVISORY UNTIL 7 AM EST FRIDAY FOR WVZ514.
DISCUSSION...FRAZIER/LUPO
AVIATION...MILCAREK
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