860
FXUS61 KPBZ 191153
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
653 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 /UNTIL 6 PM THIS EVENING/
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.
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WEAK SHORTWAVE MOVEMENT ALOFT COMBINED WITH A SURFACE LOW WILL
CREATE AN AREA OF SNOW THAT IS EXPECTED TO REMAIN SOUTH OF THE
FORECAST AREA AS IT SHIFTS TOWARD THE ATLANTIC COAST TODAY.
THERE IS SOME MODEL SIGNAL THAT THE FAR NORTHERN EDGE OF THE
SNOW BAND COULD REACH AREAS SOUTH OF I-70 INTO THE WV HIGHER
TERRAIN BETWEEN 6AM TO NOON; HOWEVER, QPF WILL BE LIGHT AND
SUGGESTS ONLY FLURRIES OR INCONSEQUENTIAL LIGHT SNOW. THE REST
OF THE REGION WILL BE STARTING OUT WITH UNSEASONABLY COLD
TEMPERATURE WITH WIND CHILLS NEAR ZERO.
THE REST OF THE DAY IS FAVORED TO BE DRY AS BRIEF RIDGING
DEVELOPS ALOFT AHEAD OF THE MAIN UPPER CLOSED LOW. EXPECT FAIRLY
ABUNDANT MID TO HIGH LEVEL CLOUDS TO DAMPEN DIURNAL HEATING AND
KEEP HIGH TEMPERATURE AROUND 20 DEGREES BELOW THE DAILY AVERAGE.
SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/
KEY MESSAGES:
- WIDESPREAD LIGHT SNOW WITH UPPER TROUGH PASSAGE LATE WEDNESDAY
NIGHT INTO THURSDAY MORNING.
- HEAVIER CONVECTIVE SNOW SHOWERS MAY CREATE LOCALIZED IMPACTS
THURSDAY AFTERNOON AND EVENING.
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THE UPPER CLOSED LOW WILL MOVE OVER CENTRAL OHIO LATE WEDNESDAY
NIGHT 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
THAN 0.5"/HR SNOWFALL RATES AND ACCUMULATIONS LESS THAN 1" TOTAL
FROM MIDNIGHT 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 /12Z 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
SHORT TERM...FRAZIER
LONG TERM...FRAZIER
AVIATION...CERMAK/MLB
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