668
FXUS61 KPBZ 200043
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
743 PM EST WED FEB 19 2025
SYNOPSIS
AFTER A DRY PERIOD THROUGH THIS EVENING, A COLD FRONT WILL BRING
THE POTENTIAL FOR SNOW SHOWERS THROUGH THE DAY ON THURSDAY. THE
SNOW SHOWERS WILL LINGER INTO THURSDAY NIGHT IN SOME CASES. DRY,
WARM AND STABLE CONDITIONS RETURN FOR THE WEEKEND.
NEAR TERM /UNTIL 6 AM THURSDAY MORNING/
KEY MESSAGES:
- SNOW SHOWERS DEVELOPING LATE TONIGHT INTO THURSDAY MORNING.
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FOR THE EVENING UPDATE, ADDED MENTION OF FLURRIES TO LOCATIONS
NORTH OF I-80, AS WEAK LAKE ENHANCEMENT APPEARS TO BE SQUEEZING
OUT A FEW FLAKES FROM TIME TO TIME. THE SAME IS TRUE FOR THE
WEST VIRGINIA RIDGES, WHERE WEAK UPSLOPING MAY BE THE MECHANISM
IN THE WAKE OF THE LOW PULLING OFF OF THE CAROLINA COAST THIS
EVENING.
MADE SOME OVERALL MINOR ADJUSTMENT TO POPS OVERNIGHT, PERHAPS A
BIT SLOWER, GIVEN SLIGHTLY SLOWER HI-RES TRENDS/ARRIVAL OF
ISENTROPIC LIFT. OVERALL EXPECTATIONS FOR NEXT 24 HOURS HAVE NOT
CHANGED, AND OTHER COSMETIC UPDATES WERE MADE TO OTHER GRIDS.
PREVIOUS DISCUSSION...
THE REST OF THE EVENING IS FAVORED TO BE DRY OVER THE NORTHERN
PORTIONS OF THE FORECAST AREA. A FEW INSTANCES OF LIGHT SNOW
WILL STILL BE POSSIBLE OVER SOUTHERN PRESTON AND TUCKER
COUNTIES. IT WILL BE NON-IMPACTFUL.
THE UPPER CLOSED LOW WILL MOVE OVER CENTRAL OHIO LATE TONIGHT
INTO EARLY THURSDAY MORNING, WITH WEAK MOIST ADVECTION AND JET
INDUCED LIFT DEVELOPING A FAIRLY BROAD AREA OF LIGHT SNOW.
ENSEMBLE MODELS FAVOR SNOW BEGINNING FOR THE EASTERN OHIO ZONES
SHORTLY AFTER MIDNIGHT BEFORE SPREADING NORTHEAST INTO THE REST
OF THE FORECAST AREA THROUGH THE REST OF THURSDAY MORNING. THE
LIGHT SNOW IMPACT WILL BE MINIMAL THROUGH THE OVERNIGHT WITH
ROUGHLY LESS THAN AN INCH EXPECTED. THE PASSAGE AND WIND SHIFT
IS EXPECTED TO OCCUR LATE TONIGHT WITH SNOW SHOWERS BEGINNING
TO DEVELOP BY 08Z TO 10Z. A WINTER WEATHER ADVISORY HAS BEEN
HOISTED BEGINNING AT 09Z TOMORROW MORNING FOR THE HIGHER
TERRAIN. THE MAIN IMPACT WILL BE JUST AFTER SUNRISE.
SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY/
KEY MESSAGES:
- WINTER WEATHER ADVISORY ISSUED FOR PA/WV RIDGES.
- HEAVIER CONVECTIVE SNOW SHOWERS MAY CREATE LOCALIZED IMPACTS
THURSDAY AFTERNOON AND EVENING.
- COLD WEATHER ADVISORY FOR E. TUCKER THURSDAY MORNING THROUGH
FRIDAY MORNING.
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BY THURSDAY MORNING, THE UPPER TROUGH WILL BEGIN TO SWING
THROUGH AS WINDS SHIFT TO THE NORTHWEST. BEHIND THE TROUGH, THE COLD
CORE LOW QUICKLY MOVES OVERHEAD AND THEN EAST OF THE REGION
THURSDAY AFTERNOON, A TRANSITION IN MODE TOWARD CONVECTIVE SNOW
SHOWERS WILL OCCUR ACROSS THE REGION. THE ENVIRONMENT IS LIKELY
TO FEATURE INCREASING NW LAKE ENHANCED MOISTURE, 30-60 J/KG
CAPE ALIGNED NICELY WITH THE DGZ, AND SOME LIFT FROM THE UPPER
LOW TO CREATE HEAVIER SNOW SHOWERS. RATES OF 0.5"/HR TO 1"/HR
WILL BE POSSIBLE WITHIN THE MORE ORGANIZED BANDS THAT COULD LEAD
TO QUICK ROADWAY ACCUMULATIONS AND DROPPING VISIBILITIES TO
LESS THAN 1 MILE. THERE REMAINS UNCERTAINTY IN SHOWERS ABILITY
TO REPEATEDLY HIT A GIVEN LOCATION TO ACCUMULATE MORE THAN 1"
TOTAL, MEANING THERE LIKELY WILL BE VARIATIONS IN TOTALS FROM
0.5" TO 2" OR LOCALLY MORE. THUS, THE WINTER WEATHER ADVISORY
HAS BEEN ISSUED FOR 09Z LATE TONIGHT THROUGH 12Z FRIDAY. IN
ADDITION, THE COLDER AIR INFILTRATING THE REGION WILL MAKE FOR
LOW WIND CHILLS AND COLDER TEMPERATURES IN THE HIGHEST TERRAIN.
THUS, HAVE GONE WITH A COLD WEATHER ADVISORY FROM THURSDAY
MORNING THROUGH FRIDAY MORNING.
LOSS OF INSTABILITY AND FURTHER EROSION OF UPPER SUPPORT SHOULD
CAUSE A DOWNWARD TREND IN COVERAGE AND INTENSITY OF SNOW
THURSDAY NIGHT. THAT SAID, STREAMING OF COLDER AIR OVER THE WARM
LAKES MAY RESULT IN A COUPLE LAKE BANDS THAT CONTINUE INTO AND
THROUGH THE DAY ON FRIDAY. FAVORED LOCATIONS FOR THESE BANDS
REMAINS TO FINE DETAIL TO SORT AT THE MOMENT, BUT BEARS
MONITORING AS THE PERIOD APPROACHES. LINGERING LAKE EFFECT SNOW
BANDS WILL TAPER OFF THROUGH THE MORNING FRIDAY AS DRY ADVECTION
AND BUILDING SURFACE HIGH PRESSURE UNDERNEATH HEIGHT RISES
ALOFT OCCUR.
LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/
KEY MESSAGES:
- HIGH PROBABILITY IN RIDGING AND TEMPERATURE MODERATION
THROUGH THE WEEKEND.
- PRECIPITATION CHANCES TETHERED TO SHORTWAVE MOVEMENT WITHIN
THE BROADER NW FLOW PATTERN.
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RIDGING AND WARMING IS EXPECTED FOR THE WEEKEND AS THIS PERIOD
WILL FEATURE TEMPERATURE MODERATION ACROSS THE REGION AS HIGHS
RISE APPROXIMATELY 6 TO 8 DEGREES EACH DAY. SUNDAY IS TRENDING
TO BE THE PEAK OF TEMPERATURE MODERATION AS HIGHS FALL ONLY 5
DEGREES SHORT OF THE DAILY AVERAGE; THERE IS SOME VARIABILITY IN
THAT TREND BASED ON POSITIONING AND SHORTWAVE MOVEMENT WITHIN
THE BROADER NW FLOW PATTERN.
THAT PATTERN IS FAVORED TO BECOME MORE ACTIVE BY THE START OF
NEXT WEEK WITH A SERIES OF SHORTWAVES MOVE ACROSS THE GREAT
LAKES REGION AND PROMOTE INCREASED PRECIPITATION CHANCES. TIMING
OF THE PRECIPITATION AND DEPTH OF THE COLD ADVECTION WILL
GREATLY INFLUENCE PRECIPITATION TYPE AND WINTRY ACCUMULATIONS,
BUT THIS IS LIKELY TO BE THE START OF ANOTHER BELOW AVERAGE
TEMPERATURE THAT SHOULD GENERALLY PERSIST THROUGH THE END OF THE
MONTH.
AVIATION /01Z THURSDAY THROUGH MONDAY/
LIGHT WINDS AND VFR TO CONTINUE INTO THE OVERNIGHT HOURS AT ALL
TERMINALS EXCEPT FKL, WHERE A LOWER MVFR SHIELD HAS SETTLED IN AFTER
COMING OFF THE LAKE.
PROBABILITIES FOR MVFR CIGS INCREASE AFTER 06Z FROM SW TO NE AS LOW-
LEVEL MOISTURE ADVECTS IN AND SNOW APPROACHES. PROBABILITIES OF MVFR
CIGS PEAK >80% AT ALL TERMINALS BY 12Z. VIS WILL QUICKLY DROP TO IFR
IN -SN MOST LIKELY AFTER 08Z FOR ZZV, 11Z AT PIT, AND 12Z AT
FKL/DUJ. THERE REMAINS SOME UNCERTAINTY AS TO HOW LONG THE IFR
VIS HOLDS ON AS CAMS DISAGREE ON THE RESIDENCE TIME OF THE
SHIELD OF SNOW AS IT PROGRESSES NORTH AND EAST; MOST LIKELY END
TIME OF THE HEAVIEST OF THE PRIMARY BATCH OF SNOW IS AROUND 12Z
FOR ZZV AND 15- 16Z FOR PIT, BUT COULD FALL +/- 1 TO 2 HOURS
WITH SOME IMPROVEMENT POSSIBLE THEREAFTER.
AFTER THIS INITIAL PUSH OF SNOW, COVERAGE IS FAVORED TO TRANSITION
TO CELLULAR BANDS AS COLD ADVECTION STEEPENS LAPSE RATES AND
PROMOTES MARGINAL SBCAPE VALUES. 60-80% PROBS FOR MVFR CIGS HOLD ON
INTO THE AFTERNOON, THOUGH MIXING SHOULD LIFT BASES SOME, AND VIS IS
LIKELY TO IMPROVE TO HIGH-END MVFR/LOW-END VFR OUTSIDE OF SNOW
BANDS. BRIEF, PERIODIC DROPS BACK TO IFR CONDITIONS ARE LIKELY IN
ANY OF THE SNOW BANDS. AS SUCH, THESE BANDS HAVE BEEN INCLUDED
AS PROB30 GROUPS FOR ALL TERMINALS THURSDAY AFTERNOON. THE
PROBABILITY OF OCCURRENCE FOR THESE SNOW BANDS IS RATHER HIGH,
MORE SO THAN A PROB30 WOULD SUGGEST. THE LOW CONFIDENCE PIECE OF
THIS FORECAST IS THE EXACT AREAL COVERAGE AND EXTENT OF SAID
SNOW BANDS.
OUTLOOK...
BANDED SNOW SHOWERS ARE EXPECTED TO BEGIN TO WANE NEAR/AFTER 00Z
FRIDAY. IT REMAINS POSSIBLE THAT SOME LAKE INFLUENCED BANDS
CONTINUE AFTER THIS TIME PERIOD, WITH FKL/DUJ BEING THE MOST
LIKELY RECIPIENTS. DRIER WEATHER WITH GENERALLY LIGHT WIND IS
FAVORED TO RETURN TO CLOSE OUT THE WEEK AND HEAD INTO THE
WEEKEND UNDER BUILDING HIGH PRESSURE.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...WINTER WEATHER ADVISORY FROM 4 AM THURSDAY TO 7 AM EST FRIDAY
FOR PAZ074-076-078.
OH...NONE.
WV...WINTER WEATHER ADVISORY FROM 4 AM THURSDAY TO 7 AM EST FRIDAY
FOR WVZ510>514.
COLD WEATHER ADVISORY FROM 7 AM THURSDAY TO 10 AM EST FRIDAY
FOR WVZ514.
SYNOPSIS...SHALLENBERGER
NEAR TERM...CL/SHALLENBERGER
SHORT TERM...SHALLENBERGER
LONG TERM...FRAZIER/SHALLENBERGER
AVIATION...MLB/AK
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