354
FXUS61 KPBZ 160808
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
308 AM EST FRI JAN 16 2026
WHAT HAS CHANGED
PROBABILITIES FOR IMPACTFUL SNOW TONIGHT/SATURDAY HAVE
INCREASED. WINTER WEATHER ADVISORIES WERE ISSUED FOR THE RIDGES
AND PORTIONS OF NW PA WHERE 3-6" IS EXPECTED ON AVERAGE.
KEY MESSAGES
1) WINTER WEATHER ADVISORY IN THE RIDGES AND PORTIONS OF NW
PENNSYLVANIA TONIGHT THROUGH SATURDAY.
2) VERY COLD TEMPERATURES MONDAY AND TUESDAY BEHIND AN ARCTIC
COLD FRONT.
3) ACTIVE PATTERN THROUGH MUCH OF NEXT WEEK.
DISCUSSION
KEY MESSAGE 1... WINTER WEATHER ADVISORY IN THE RIDGES AND
PORTIONS OF NW PENNSYLVANIA TONIGHT THROUGH SATURDAY.
SURFACE LOW PRESSURE WILL CROSS THE GREAT LAKES TODAY INTO
SATURDAY AS A SERIES OF UPPER SHORTWAVES TRAVERSE THE FLOW.
LIGHT SNOW SHOWERS ARE POSSIBLE THIS AFTERNOON AHEAD OF THE
FIRST OF THESE WAVES AND LOW/MID LEVEL ISENTROPIC LIFT, THOUGH
THIS WILL LIKELY BE LIMITED BY DRY AIR NEAR THE SURFACE. BETTER
SNOWFALL IS EXPECTED WITH AN INITIAL COLD FRONT THIS EVENING
INTO THE OVERNIGHT. SNOW IS EXPECTED TO BECOME MORE CONVECTIVE
AND CELLULAR BY SUNRISE SATURDAY, WITH THE POSSIBILITY OF
BANDING INTO SATURDAY AFTERNOON.
SNOWFALL AMOUNTS WILL REMAIN A GENERALLY LIGHT 1-2" OUTSIDE OF
THE ADVISORY AREA DUE TO A COMBINATION OF WEAKER ASCENT/LIMITED
SURFACE FORCING, MODEST 700MB WARMING THAT WILL REDUCE SLRS,
AND WESTERLY FLOW THAT WILL PREVENT LAKE ENHANCEMENT. HOWEVER,
SAID WESTERLY FLOW WILL ACT TO ENHANCE SNOWFALL ACROSS THE
ALLEGHENY MOUNTAINS INTO THE LAURELS WITH TOPOGRAPHIC LIFT.
PROBABILITIES FOR MORE THAN 3 INCHES HAVE INCREASED IN THOSE
LOCATIONS, WITH HIGHEST PROBABILITIES OVER EASTERN PRESTON
COUNTY, WV. TOTALS UP TO 6 INCHES ARE EXPECTED IN THOSE
LOCATIONS WHERE A WINTER WEATHER ADVISORY IS IN EFFECT FROM 10PM
FRIDAY THROUGH 7PM SATURDAY.
ADDITIONAL ENHANCEMENT IS EXPECTED ACROSS PORTIONS OF NW
PA, LEADING TO 3-5" IN PORTIONS OF CLARION, FOREST, AND
JEFFERSON COUNTIES. SNOW MAY BEGIN A LITTLE EARLIER THERE AND
ALSO LINGER INTO SATURDAY NIGHT. THE ADVISORY FOR THESE COUNTIES
WILL BEGIN AT 7PM FRIDAY, CONTINUING THROUGH 1AM SUNDAY.
SNOW RATES WILL REMAIN RELATIVELY LOW THROUGH MUCH OF TONIGHT:
AROUND 0.5 IN/HR IN THE WV RIDGES AND UP TO 0.2-0.3 IN/HR
ELSEWHERE. BETTER RATES ARE EXPECTED WITH MORE CONVECTIVE SNOW
SHOWER ACTIVITY SATURDAY MORNING INTO THE AFTERNOON, WITH BRIEF
AND ISOLATED RATES UP TO AROUND AN INCH PER HOUR POSSIBLE IN
BANDS. THE BTV SNOW SQUALL PARAMETER DOES INDICATE GOOD
CONDITIONS FOR SNOW SQUALLS EARLY SATURDAY AFTERNOON. THESE
BANDS/SQUALLS MAY ALSO LOCALLY ENHANCE SNOWFALL AMOUNTS OUTSIDE
OF ADVISORY AREAS, THOUGH PREDICTABILITY IN EXACT LOCATIONS FOR
THIS REMAINS LOW.
KEY MESSAGE 2... VERY COLD TEMPERATURES MONDAY AND TUESDAY.
A COLD AIR MASS WILL MOVE INTO THE OHIO VALLEY BEHIND THE
STRONGER, SECONDARY COLD FRONT ON SUNDAY. THIS AIR MASS WILL
REMAIN IN PLACE THROUGH THE MIDDLE OF NEXT WEEK. THE COLDEST
PERIOD OF THE WEEK APPEARS TO BE MONDAY NIGHT INTO TUESDAY.
AFTER HIGHS IN THE 20S ON MONDAY, TEMPERATURES ARE EXPECTED TO
PLUNGE INTO THE SINGLE DIGITS BY EARLY TUESDAY -- NOT MAKING IT
OUT OF THE TEENS TUESDAY AFTERNOON. THESE COLD TEMPERATURES WILL
BE COMBINED WITH WIND GUSTS FROM 20-30MPH MONDAY AND TUESDAY,
LEADING TO TUESDAY MORNING WIND CHILLS RANGING FROM -10 TO -20F
ACROSS THE REGION. A COLD WEATHER ADVISORY WILL LIKELY BE NEEDED
FOR ALL OF THE FORECAST AREA.
LITTLE IMPROVEMENT IS EXPECTED THROUGH THE DAY TUESDAY AS SOME
LOCATIONS MAY NOT SEE POSITIVE WIND CHILLS THROUGH THE DAYTIME.
WARM ADVECTION TUESDAY NIGHT AND WEDNESDAY SHOULD HELP MODERATE
TEMPERATURES BACK TO NEAR NORMAL.
KEY MESSAGE 3... ACTIVE PATTERN THROUGH MUCH OF NEXT WEEK.
PERSISTENT EASTERN CONUS UPPER TROUGHING, A SERIES OF
SHORTWAVES, AND SEVERAL SURFACE LOW PRESSURE SYSTEMS WILL KEEP
THE PATTERN ACTIVE THROUGH THE 7 DAY, THOUGH SOME DAYS WILL BE
DRIER THAN OTHERS. ENSEMBLE GUIDANCE CONTINUES TO INDICATE NEAR
TO BELOW NORMAL TEMPERATURE THROUGH NEXT WEEK, WHICH WOULD KEEP
MORE PRECIPITATION AS SNOW. AFTER THE WEEKEND SYSTEM AND CHANCES
ON MONDAY, THE NEXT WIDESPREAD PRECIPITATION CHANCE APPEARS TO
BE LATE WEEK WITH ANOTHER CROSSING LOW PRESSURE.
AVIATION /08Z FRIDAY THROUGH TUESDAY/
KEY MESSAGES...
1) VFR RETURNING THROUGH MOST OF FRIDAY WITH SCATTERING AND A
TEMPORARY DEPARTURE OF SNOW
2) TURNING GUSTY FRIDAY AFTERNOON WITH A PERIOD OF LATE EVENING
SHEAR POSSIBLE
3) SNOW RETURNS AGAIN LATE FRIDAY INTO EARLY SATURDAY
------------------------------------------------------------
VFR HAS RETURNED TO ALL SITES SAVE FKL/DUJ WHERE LINGERING LIGHT
SNOW AND HIGH-END MVFR DECKS CONTINUE WITH LAKE ENHANCEMENT IN
NORTHWEST FLOW. WIND DIRECTION WILL BACK OVERNIGHT AND CUT OFF
THE LAKE SOURCE RETURNING VFR AFTER 08Z. QUICKLY IN THE WAKE OF
THAT, A SHIELD OF SCT TO BKN CLOUD COVER AROUND 3.5 KFT IS
FILLING IN ON THE NOSE OF 925-850 MB WARM ADVECTION, AND
EXPECTATION IS THAT THIS REMAINS >3 KFT BASED ON HI RES
SOUNDINGS AND UPSTREAM OBSERVATIONS.
BY MORNING, THE STRATUS SHOULD CLEAR AND GIVE WAY TO A
THICKENING AND GRADUALLY LOWERING DECK OF MID-LEVEL CLOUDS
THROUGH THE DAY AHEAD OF APPROACHING LOW PRESSURE. GUSTS LOOK
TO PICK UP IN THE AFTERNOON WITH MIXING HEIGHTS TAPPING INTO
25-35 KNOTS OF LOW LEVEL FLOW. SNOW CHANCES THEN INCREASE TOWARD
THE END OF THE CURRENT TAF PERIOD AS A WARM FRONT LIFTS
THROUGH. PROBABILITY FOR SNOW INCREASES AFTER 00Z SATURDAY, BUT
DRY LOW-LEVEL AIR AT ONSET WITH LARGE T/TD SPREADS WILL WORK
AGAINST FLAKES MAKING IT TO THE GROUND FOR THE FIRST HOUR OR
TWO; CEILINGS AS A RESULT WILL TAKE A BIT TO COME DOWN AS WILL
VISIBILITY. PROBABILITY FOR MVFR EVENTUALLY REACHES 80+% WITH
SATURATION AND PREVAILING IFR ONLY AROUND 40%, BUT INTERMITTENT
PERIODS OF IFR WITHIN STEADIER SNOW ARE HIGHER LIKELIHOOD AFTER
06Z. DECOUPLING MAY ALSO LEAD TO A BRIEF BOUT OF SHEAR IN THE
EARLY OVERNIGHT PERIOD UNDER A SHORT-LIVED 35-45 KNOT LOW LEVEL
JET.
OUTLOOK...
RESTRICTIONS ARE FAVORED TO HOLD ON THROUGH SATURDAY WITH LOW-
LEVEL COLD ADVECTION REINFORCING MVFR CEILINGS AND SCATTERED
AFTERNOON SNOW SHOWERS CONTINUING. DRIER AIR WORKS IN IN THE
WAKE OF A COLD FRONT PASSAGE SATURDAY EVENING WHICH SHOULD THEN
ERODE CEILINGS AND RETURN VFR CONDITIONS OVERNIGHT.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 1 AM EST
SUNDAY FOR PAZ009-015-016.
WINTER WEATHER ADVISORY FROM 10 PM THIS EVENING TO 7 PM EST
SATURDAY FOR PAZ076.
OH...NONE.
WV...WINTER WEATHER ADVISORY FROM 10 PM THIS EVENING TO 7 PM EST
SATURDAY FOR WVZ510>514.
COLD WEATHER ADVISORY UNTIL 7 AM EST THIS MORNING FOR WVZ514.
DISCUSSION...RACKLEY/FRAZIER
AVIATION...MLB
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