975
FXUS61 KPBZ 191559
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
1059 AM EST WED FEB 19 2025
SYNOPSIS
LIGHT SNOW CAN'T BE RULED OUT FOR LOCALES SOUTH OF INTERSTATE 70
TODAY, BUT MORE WIDESPREAD LIGHT SNOW IS EXPECTED OVERNIGHT
TONIGHT THROUGH EARLY FRIDAY MORNING. MODERATING TEMPERATURE
WILL OCCUR INTO THE WEEKEND BEFORE A MORE ACTIVE WEATHER PATTERN
DEVELOPS AND MAINTAINS BELOW AVERAGE TEMPERATURE.
NEAR TERM /THROUGH TONIGHT/
KEY MESSAGES:
- COLD START TO THE DAY WITH WELL BELOW AVERAGE HIGH TEMPERATURE
BY THE AFTERNOON.
- LIGHT SNOW OR FLURRIES COULD DEVELOP SOUTH OF I-70 BUT WITH
MINIMAL ACCUMULATIONS OR IMPACTS.
- WIDESPREAD LIGHT SNOW WITH UPPER TROUGH PASSAGE LATE WEDNESDAY
NIGHT INTO THURSDAY MORNING.
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THE LOW PRESSURE SYSTEM TRACKING TO THE SOUTH WILL STILL BRING
SOME LIGHT SNOW TO THE PRESTON AND TUCKER COUNTY AREAS, AND TO A
MUCH LESSER EXTENT THE REST OF THE WV COUNTIES SOUTH OF THE
MASON DIXON LINE. HI RES MODELS HAVE INDEED BUMPED THE POTENTIAL
FOR SNOW JUST A TAD BIT NORTH. THUS, HAVE ISSUED AN SPS FOR
PRESTON AND TUCKER BEING THAT THE IMPACTS WILL MAKE FOR BELOW
ADVISORY CRITERIA.
THE REST OF THE DAY IS FAVORED TO BE DRY OVER THE NORTHERN
PORTIONS OF THE FORECAST AREA. EXPECT FAIRLY ABUNDANT MID TO
HIGH LEVEL CLOUDS TO DAMPEN DIURNAL HEATING AND KEEP HIGH
TEMPERATURE AROUND 20 DEGREES BELOW THE DAILY AVERAGE.
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.
LIMITED FORCING AND MOISTURE CONTENT WILL GENERALLY LEAD TO LESS
SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/
KEY MESSAGES:
- HEAVIER CONVECTIVE SNOW SHOWERS MAY CREATE LOCALIZED IMPACTS
THURSDAY AFTERNOON AND EVENING.
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BY THURSDAY MORNING, EXPECT LESS THAN 0.5"/HR SNOWFALL RATES
AND ACCUMULATIONS LESS THAN 1" TOTAL FROM THROUGH NOON
THURSDAY. HOWEVER, NEWER HI- RES MODEL GUIDANCE SUGGESTS
POTENTIAL FOR MID-LEVEL FRONTOGENETIC FORCING THAT COULD ENHANCE
SNOWFALL RATES THAT RESULTS IN MORE NOTABLE ACCUMULATIONS.
GLOBAL MODELS HAD BEEN MORE BEARISH ON ITS DEVELOPMENT OR
POSITIONING IT SOUTH OF THE REGION, BUT THESE HI-RES MODEL
TRENDS SUGGESTS THAT AREAS NEAR THE WV HIGHER TERRAIN COULD SEE
THE FRONTOGENETIC EFFECTS. IF THIS OCCURS, 0.5"/HR RATES AND
ACCUMULATIONS OF 1-4" COULD DEVELOP IN THIS REGION AND ARE NOT
CURRENTLY REFLECTED IN THE FORECAST.
AS 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, 20-40 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. AS
CONFIDENCE IS TOO LOW ON ANY ONE AREA (INCLUDING THE WV HIGH
TERRAIN) TO RECEIVE ACCUMULATIONS TOTALING MORE THAN 3", WILL
REFRAIN ON ANY ADVISORY HEADLINE BUT MAINTAIN HWO MENTION.
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
FRIDAY. FAVORED LOCATIONS FOR THESE BANDS REMAINS TO FINE DETAIL
TO SORT AT THE MOMENT, BUT BEARS MONITORING AS THE PERIOD
APPROACHES.
LONG TERM /FRIDAY THROUGH TUESDAY/
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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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. EVEN WITH A FAIRLY
DRY (OUTSIDE OF INCREASED CLOUD COVER) SHORTWAVE CROSSING
SATURDAY, 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 /16Z WEDNESDAY THROUGH SUNDAY/
HIGH CLOUDS FILL IN FROM THE WEST THIS MORNING AS LOW PRESSURE
SKIRTS TO OUR SOUTH. CEILINGS WILL REMAIN VFR THROUGH AT LEAST
MID MORNING. THEREAFTER, HI-RES MODEL SOUNDINGS CONTINUE TO
SUGGEST A CHANCE FOR CEILINGS TO DROP TO MVFR, THOUGH THE SAME
MODELS HAVE NOTABLY STRUGGLED LATELY WITH THE MAGNITUDE OF LOW-
LEVEL DRY AIR AND THUS CONFIDENCE IN THIS OCCURRING REMAINS LOW.
FURTHER DRIVING THIS UNCERTAINTY ARE ENSEMBLE PROBABILITIES FOR
MVFR CEILINGS, WHICH CONTINUE TO HOVER AROUND 40-50% AT MOST
AREA TERMINALS THROUGHOUT THE DAY. AS SUCH, OPTED TO KEEP
RESTRICTIONS OUT OF TAFS THROUGH 00Z TONIGHT.
PRECIPITATION IS EXPECTED TO PASS LARGELY TO THE SOUTH OF THE
LOCAL AREA WITH THE INITIAL WAVE TODAY, THOUGH CHANCES BEGIN TO
CREEP HIGHER TOWARDS THE TAIL END OF THE TAF PERIOD AND JUST
BEYOND. RESTRICTIONS WILL BECOME MORE WIDESPREAD ON THURSDAY IN
-SN, AND INCLUDED THIS MENTION WITH IFR BEGINNING AT THE TAIL
END OF THE CURRENT TAF PERIOD.
WINDS REMAIN LIGHT THROUGHOUT THE TAF PERIOD AND GENERALLY OUT
OF THE NORTH OR NORTHWEST.
OUTLOOK...
PROBABILITIES OF RESTRICTIONS INCREASE THURSDAY AS AN UPPER-
LEVEL DISTURBANCE PASSES THROUGH THE AREA. DRIER WEATHER WITH
GENERALLY LIGHT WIND IS FAVORED TO RETURN TO CLOSE OUT THE WEEK
AND HEADED INTO THE WEEKEND UNDER BUILDING HIGH PRESSURE.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...NONE.
OH...NONE.
WV...NONE.
SYNOPSIS...FRAZIER
NEAR TERM...FRAZIER/SHALLENBERGER
SHORT TERM...FRAZIER
LONG TERM...FRAZIER
AVIATION...CERMAK/MLB
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