650
FXUS61 KPBZ 312340
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
640 PM EST SAT JAN 31 2026
WHAT HAS CHANGED
- NO CHANGES TO FORECAST PACKAGE AND PREVIOUS MESSAGING.
KEY MESSAGES
1) COLD AND LIGHT SNOW CHANCES THROUGH TODAY AND TONIGHT.
2) PROLONGED COLD AND PERIODIC SNOW CHANCES THROUGH NEXT WEEK.
DISCUSSION
KEY MESSAGE 1...
TONIGHT WILL CARRY THE NEXT, AND LIKELY LAST, ROUND OF COLD
WEATHER HEADLINES FOR MOST. CLOUD COVER WILL POSE MORE
UNCERTAINTY IN TRUE RADIATIVE COOLING, THOUGH WIND GUSTS MAY BE
SLIGHTLY STRONGER IN WRAP-AROUND FLOW FROM A NOR-EASTER PASSING
TO THE EAST. MOST LIKELY WIND CHILLS SIT IN THE 5 TO 15 BELOW
RANGE OVERNIGHT, PRIMARILY FOR THE HILLTOPS. LOWER VALUES OF
DOWN TO 15 TO 25 BELOW ZERO ARE POSSIBLE FOR THE RIDGES OF PA
AND WV.
EMBEDDED SHORTWAVE RIDGING IS FAVORED TO SUPPORT DRY CONDITIONS
SUNDAY, THOUGH UPSLOPE FLOW AND/OR WEAK ASCENT AHEAD OF THE
RIDGE AXIS MAY RESULT IN POCKETS OF FLURRIES SQUEEZE OUT OF THE
THIN STRATOCUMULUS LAYER. TEMPERATURE MODERATION NORMALLY WOULD
BE FAVORED AMID THESE HEIGHT RISES (AND MAY BE SEEN FOR PORTIONS
OF EASTERN OH) BUT LINGER CLOUDS MAY INHIBIT THE INSOLATION
BOOST NEEDED TO GET THE REST OF THE AREA SITES ABOVE 20 DEGREES.
FORTUNATELY, LIGHT WIND DURING THE PERIOD DIMINISHES THE NEED
FOR ADDITIONAL COLD HEADLINES THE FOLLOWING NIGHT.
KEY MESSAGE 2...
LONGWAVE TROUGHING IS FAVORED TO PERSIST OVER EASTERN NORTH
AMERICA THROUGHOUT THE UPCOMING WEEK. THIS WILL SUPPORT THE
CONTINUATION OF COLD TEMPERATURES, WITH EVEN THE WARMEST DAYS
APPEARING TO BARELY REACH OR EXCEED FREEZING. IN FACT, THE
LATEST NBM PROBABILITIES SUGGEST ONLY A 20-40 PERCENT CHANCE OF
REACHING 32 DEGREES ON TUESDAY (FOCUSED SOUTH OF I-70) AND A
30-60% CHANCE ON FRIDAY (HIGHEST IN EASTERN OH AND THE MON
VALLEY). GIVEN THE FACT THAT THE AVERAGE HIGH TEMPERATURE THIS
TIME OF YEAR IS THE UPPER 30S, THERE IS MEDIUM TO HIGH
CONFIDENCE IN MOST OF THE WEEK REMAINING COLDER THAN SEASONAL
NORMS.
MEANWHILE, A FEW GLANCING BLOWS FROM QUICK-MOVING SHORTWAVE
TROUGHS COULD BRING LOW-END CHANCES FOR SOME LIGHT SNOW SHOWERS
TO THE AREA MONDAY THROUGH WEDNESDAY, BUT POPS CURRENTLY TOP OUT
IN THE 20-30 PERCENT RANGE ANY GIVEN DAY AS A LACK OF DEEP-
LAYER MOISTURE KEEPS RATES LIGHT WITH MINIMAL ACCUMULATION. THE
LATEST NBM SUGGESTS ONLY A 10-20% CHANCE FOR AT LEAST 0.1" OF
SNOW ON MONDAY MAINLY IN THE RIDGES AND ALONG A MERCER-LATROBE
CORRIDOR, FOLLOWED BY HIGHER PROBABILITIES (UP TO 40%) IN THE
RIDGES AND MON VALLEY SOUTHEAST OF PITTSBURGH LATE TUESDAY AS
SURFACE LOW PRESSURE PASSES SOUTH OF THE AREA. STILL, GIVEN HOW
COLD THE GROUND IS WITH THE RECENT STRETCH OF BITTER COLD, ANY
SNOW THAT DOES FALL WILL STICK TO UNTREATED SURFACES AND COULD
CAUSE ROADS TO BECOME SLICK.
RIGHT NOW, THE BETTER CHANCE FOR NOTABLE SNOWFALL ACCUMULATION
APPEARS TO BE WITH THE SYSTEM AT THE END OF THE WEEK. BY THEN, A
DEEPENING UPPER LOW IS FORECAST TO SWING SOUTHEASTWARD FROM
CENTRAL CANADA INTO SOUTHERN ONTARIO, BRINGING STRONGER SYNOPTIC
ASCENT TO THE OHIO VALLEY AS A SURFACE LOW MOVES ACROSS LOWER
ONTARIO AND THE LOWER GREAT LAKES. THE SOURCE LOCATION AND
TRAJECTORY OF THIS LOW WOULD MAKE IT DIFFICULT TO ESTABLISH A
NOTABLE "WARM" SECTOR, HENCE TEMPERATURE FORECASTS REMAINING
NEAR OR BARELY ABOVE FREEZING ON FRIDAY AND A PREVAILING PTYPE
OF SNOW, EVEN AS WINDS SHIFT OUT OF THE SOUTH OR SOUTHWEST. AS
FOR SNOWFALL AMOUNTS, LATEST LONG- RANGE ENSEMBLE INTERQUARTILES
FAVOR SUB- ADVISORY SNOWFALL (LESS THAN 3 INCHES) ACROSS
LOWLAND AREAS AND HIGHER AMOUNTS (3 TO 6 INCHES) IN THE RIDGES.
HOWEVER, THESE NUMBERS SHOULD ALL BE TAKEN WITH A HEAPING
TABLESPOON OF SALT THIS FAR OUT. WHAT APPEARS MORE LIKELY WITH
THE FRIDAY SYSTEM IS A REINFORCING SHOT OF THE CRISP NORTHERN
CANADIAN AIR WE'VE GROWN TO LOVE (OR HATE) OVER THE PAST WEEK,
WITH ENSEMBLES SHOWING LOW TEMPERATURES DROPPING BACK TO NEAR OR
BELOW ZERO NEXT WEEKEND.
AVIATION /00Z SUNDAY THROUGH THURSDAY/
KEY MESSAGES...
1) MVFR CIG RESTRICTIONS FAVORED THROUGH THE TAF PERIOD
2) LOW PROBABILITY FLURRIES POSSIBLE, BUT TOO UNCERTAIN FOR TAF
MENTION OUTSIDE OF FKL
------------------------------------------------------------
DEVELOPING NORTHWEST FLOW AS A DEEPER UPPER TROUGH/SURFACE LOW
SYSTEM MOVES TOWARD THE ATLANTIC COAST WILL DRAW AREAS OF MVFR
CIG INTO THE REGION THAT ARE LIKELY (60-80% PROBABILITY) TO
LINGER THROUGH THE MAJORITY OF THE TAF PERIOD. DUE TO LAKE ERIE
BEING NEARLY FROZEN AND THE MOISTURE SOURCE (LAKE HURON) BEING
FARTHER AWAY, PERIODS OF STRATOCU SCATTERING RESULTING IN VFR
CONDITIONS ARE POSSIBLE BUT TIMING OF SUCH FEATURES IS
UNCERTAIN. THERE ALSO MAY BE ENOUGH LIFT TO SQUEEZE A FEW
FLURRIES (MOST LIKELY AT FKL, BUT AS FAR SOUTH OF PIT) DURING
THE OVERNIGHT PERIOD. HOWEVER, CONFIDENCE IS VERY LOW ON TIMING
AND DURATION OF ANY FALLING SNOW, SO IT WAS GENERALLY PRECLUDED
FROM TAF MENTION.
GRADUAL SOUTHWEST TO NORTHEAST LIFTING OF THE STRATOCU
UNDERNEATH UPPER SHORTWAVE RIDGINE IS EXPECTED BY MAY BEGIN
TOWARD THE END OF THE TAF PERIOD. LOOK FOR OCCASIONAL WNW TO NW
GUSTS UP TO 20KTS IN THE AFTERNOON.
OUTLOOK...
OCCASIONAL SHORTWAVE MOVEMENT MONDAY THROUGH WEDNESDAY MAY OFFER
PERIODS OF LIGHT SNOW AND MVFR RESTRICTIONS AMID A MORE
PREVAILING VFR PATTERN.
MORE WIDESPREAD AND HEAVIER SNOW COULD DEVELOP WITH A LATE WEEK
INTO EARLY WEEKEND SYSTEM, BUT VARIABILITY IN
TIMING/PRECIPITATION COVERAGE FOR THIS TIME FRAME REMAINS HIGH.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...COLD WEATHER ADVISORY UNTIL 11 AM EST SUNDAY FOR PAZ013>016-
020>022-029-031-073>078.
AIR QUALITY ALERT UNTIL 10 PM EST THIS EVENING FOR PAZ021.
OH...COLD WEATHER ADVISORY UNTIL 11 AM EST SUNDAY FOR OHZ039>041-
048>050-057>059-068-069.
WV...COLD WEATHER ADVISORY UNTIL 11 AM EST SUNDAY FOR WVZ001>004-
012-021-509>513.
EXTREME COLD WARNING UNTIL 1 PM EST SUNDAY FOR WVZ514.
DISCUSSION...CERMAK/SHALLENBERGER
AVIATION...FRAZIER
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