639
FXUS61 KPBZ 270809
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
309 AM EST TUE JAN 27 2026
WHAT HAS CHANGED
- CHANCES OF SNOW HAVE INCREASED SOME DURING THE DAY TODAY FROM
THE LAST UPDATE.
- TEMPERATURES WERE UPDATED FOR THE PERIOD, ALTHOUGH THERE WAS
LITTLE CHANGE TO VALUES.
- THE EXTREME COLD WARNING NOW CONTINUES THROUGH 11AM WEDNESDAY
FOR EASTERN TUCKER COUNTY. A COLD WEATHER ADVISORY WAS ISSUED
FOR THE REST OF THE AREA FROM 7PM TONIGHT TO 11AM WEDNESDAY.
KEY MESSAGES
1) LIGHT SNOW TODAY.
2) RECORD COLD POSSIBLE THIS WEEK.
3) A EYE ON WEEKEND WINTER WEATHER CHANCES.
DISCUSSION
KEY MESSAGE 1...
BROAD SHORTWAVE ENHANCED ASCENT IS FORECAST THROUGHOUT THE
MORNING AND AFTERNOON. FOR THE BEGINNING OF THE DAY, BROAD
ASCENT IS FORECAST IN THE NEAR-SURFACE LAYER, THERMODYNAMIC
PROFILES ARE FORECAST RELATIVELY STABLE IN THE SATURATED LAYER.
THIS SUGGESTS MORE OF A STRATIFORM COVERAGE EARLY. THE FORECAST
SATURATED LAYER IN THE DGZ MAY MUSH SNOW RATIOS TOWARD 20:1 AND
25:1. LATER IN THE DAY, THE ARRIVAL OF THE SHORTWAVE AND COLD
AIR ALOFT COMBINED WITH DIURNAL HEATING MAY TEND SNOW COVERAGE
TO MORE SCATTERED AND "SHOWERY" WITH ADIABATIC LAPSE RATES IN
THE SURFACE TO 850MB LAYER, THOUGH SATURATION MAY EXTEND ABOVE
THE DGZ. ALL SNOW WILL BE DRY AND POWDERY.
USING HREF AND EXPECTED RATIOS, THERE IS A 50% TO 80% CHANCE OF
EXCEED ONE INCH OF SNOW ACCUMULATIONS IN NORTHWEST PA AND IN THE
PA/WV RIDGES. CHANCES ARE GENERALLY LESS THAN 30% ELSEWHERE.
CHANCES OF ADVISORY SNOW MAXIMIZE AT ONLY 25% AT LAUREL SUMMIT,
SO NO PRODUCTS WERE CONSIDERED.
KEY MESSAGE 2...
EXTREMELY COLD TEMPERATURES AS LOW AS 20 TO 30 DEGREES BELOW NORMAL
ARE EXPECTED THROUGH AT LEAST SUNDAY WITH HIGH CONFIDENCE. THIS
PROLONGED COLD WILL CONTINUE TO POSE A THREAT TO VULNERABLE
POPULATIONS AND CARRY THE POTENTIAL TO RUPTURE PIPES. RECOMMENDED
ACTIONS INCLUDE MINIMIZING TIME OUTDOORS, HAVING A PLAN FOR
POWER OUTAGES, AND CHECKING ON FRIENDS AND FAMILY TO MAKE SURE
THEY ARE OK. KEEP PETS WARM, DRY, AND INDOORS AS MUCH AS
POSSIBLE. IF POSSIBLE, INSULATE PIPES OR LEAVE FAUCETS ON A SLOW
DRIP TO PREVENT RUPTURE.
AN EXTREME COLD WARNING CONTINUES FOR THE ENTIRE AREA THROUGH
11AM, SAVE EASTERN TUCKER COUNTY WHERE IT CONTINUES THROUGH
WEDNESDAY. A COLD WEATHER ADVISORY HAS BEEN ISSUED FOR THE REST
OF THE AREA FROM 7PM TONIGHT TO 11AM WEDNESDAY. THIS COLD WILL
CHALLENGE MANY AREA RECORDS (SEE CLIMATE SECTION). THIS MAY BE
ONE OF 10 TIMES IN PITTSBURGH HISTORY WHERE THE AVERAGE TEMP
WAS RECORDED AT 15F OR LOWER FOR 8 CONSECUTIVE DAYS. THE COLD
WILL ALLOW ANY SNOW THAT IS NOT PLOWED OR SHOVELED TO REMAIN IN
PLACE AND FROZEN THROUGH THE WEEK, MAKING TRAVEL DIFFICULT ON
BACK-ROADS. RAPID ICE GROWTH ON AREA RIVERS WILL CONTINUE. THIS
WILL RAISE CONCERNS FOR RIVER FLOODING AND ICE JAMS AS THE AREA
HEADS INTO FEBRUARY.
KEY MESSAGE 3...
ENSEMBLES ALLUDE TO THE POTENTIAL FOR A NOR'EASTER TO FORM THIS
WEEKEND, ALTHOUGH THE EXACT DETAILS ARE STILL FUZZY WITH
UNCERTAINTY IN THE LOCATION OF THE PRIMARY UPPER LOW FORMATION.
HERE'S WHAT WE KNOW: A REINFORCING UPPER TROUGH WILL DIVE INTO
THE EASTERN US LATE THIS WEEK FORCING SURFACE CYCLOGENESIS ON
THE EASTERN SEABOARD. HERES WHERE THE UNCERTAINTY LIES:
IN ONE SCENARIO, THE UPPER LOW OCCLUDES EARLIER (FRIDAY INTO
SATURDAY), FORCING SURFACE CYCLOGENESIS TIGHTER TO THE COAST. IN
THIS SCENARIO, THERE MAY BE ASCENT IN THE NORTHWEST QUADRANT OF
THE LOW AND THE POTENTIAL FOR FRONTOGENETICAL BANDING (HIGHEST
PROBABILITY IN WESTERN/CENTRAL PA AND NORTHERN WV). USING A
QUICK PROBABILITY OF 0.15" QPF (APPROX 3" OF SNOW AT 20:1), THIS
WOULD PRODUCE ~60% CHANCE OF AT LEAST ADVISORY SNOWS. THOUGH
THIS SCENARIO IS AROUND 25% LIKELY OVERALL.
IN THE OTHER SCENARIO, THE TROUGH EITHER DOES NOT PRODUCE A
CLOSED LOW OR PRODUCES A CLOSED LOW TOO LATE AND OFF THE
ATLANTIC COAST. THIS WOULD PRODUCE CYCLOGENESIS TOO FAR EAST,
ONLY RESULTING IN A ~10% CHANCE OF ADVISORY SNOWS. THIS SCENARIO
IS 75% LIKELY OVERALL.
AVIATION /06Z TUESDAY THROUGH SATURDAY/
KEY MESSAGES...
1) MVFR AND IFR CIGS WITH LIGHT SNOW THROUGH THE NIGHT
2) MORE RESTRICTIONS AND LIGHT SNOW TUESDAY
------------------------------------------------------------
EXPECT A FEW INSTANCES OF LIGHT SNOW THROUGH THE NIGHT. THE
LINGERING LOW LEVEL CLOUD COVER WILL LIKELY REMAIN THROUGH THE
NIGHT AND INTO THE COMING DAY. THUS, EXPECT THE MVFR AND IFR
CIGS TO REMAIN INTO THE COMING DAY. A REINFORCING COLD FRONT IS
EXPECTED TOMORROW WHICH WILL BRING GENERALLY LIGHT SNOW AND
AREAWIDE RESTRICTIONS. ACCUMULATIONS FOR MOST LOCATIONS SHOULD
BE LESS THAN AN INCH.
A TIGHT PRESSURE GRADIENT IN THE ACTIVE PATTERN AND STRONG WINDS
ALOFT WITH RESULT IN A PERSISTENT GUSTY WEST WIND, ESPECIALLY
DURING THE DAY WITH DAYTIME MIXING. EXPECT WSW WINDS GUSTING
UP TO 30 KNOTS AT TIMES.
OUTLOOK...
RESTRICTIONS WILL LIKELY CONTINUE INTO TUESDAY EVENING AS THE
FRONT CROSSES. ANOTHER REINFORCING FRONT WILL LIKELY RETURN
RESTRICTIONS AND SNOW CHANCES LATER WEDNESDAY INTO THURSDAY,
WITH ANOTHER LATE FRIDAY INTO SATURDAY.
CLIMATE
AN ANOMALOUSLY COLD AIRMASS WILL CHALLENGE SOME AREA RECORDS
FOR DAILY COLD TEMPERATURES AND DURATION OF COLD TEMPERATURES.
VARIOUS COLD RECORDS ARE LISTED BELOW FOR REFERENCE.
DAILY COLD RECORDS AT RISK OF BEING BROKEN:
DUBOIS, PA (1/27 DAILY LOW MIN TEMP RECORD) -5F (2003)
PITTSBURGH, PA (1/30 DAILY LOW MIN TEMP RECORD) -5F (2019)
PITTSBURGH, PA (1/30 DAILY LOW MAX TEMP RECORD) 10F (1977)
DUBOIS, PA (1/30 DAILY LOW MIN TEMP RECORD) -10F (2019)
WHEELING, WV (1/30 DAILY LOW MIN TEMP RECORD) -5F (2019)
WHEELING, WV (1/30 DAILY LOW MAX TEMP RECORD) 12F (1934)
ZANESVILLE, OH (1/30 DAILY LOW MIN TEMP RECORD) -4F (2019)
WHEELING, WV (1/31 DAILY LOW MAX TEMP RECORD) 12F (2019)
WHEELING, WV (1/31 DAILY LOW MAX TEMP RECORD) 12F (1965)
MOST CONSECUTIVE DAYS WITH TEMP BELOW <=25F IN PITTSBURGH:
1) 15 DAYS - ENDING FEBRUARY 3RD, 1961
2) 12 DAYS - ENDING JANUARY 6TH, 2018
T2) 12 DAYS - ENDING DECEMBER 26TH, 1989
T2) 12 DAYS - ENDING FEBRUARY 19TH, 1958
5) 11 DAYS - ENDING DECEMBER 16TH, 1958
T5) 11 DAYS - ENDING FEBRUARY 2ND, 1936
MOST CONSECUTIVE DAYS WITH MINIMUM TEMP <=10F IN PITTSBURGH:
1) 14 DAYS - ENDING FEBRUARY 2ND, 1936
T1) 14 DAYS - ENDING JANUARY 17TH, 1912
3) 11 DAYS - ENDING DECEMBER 24TH, 1989
T3) 11 DAYS - ENDING JANUARY 13TH, 1981
5) 10 DAYS - ENDING FEBRUARY 21ST, 2015
PBZ WATCHES/WARNINGS/ADVISORIES
PA...EXTREME COLD WARNING UNTIL 11 AM EST THIS MORNING FOR
PAZ007>009-013>016-020>022-029-031-073>078.
COLD WEATHER ADVISORY FROM 7 PM THIS EVENING TO 11 AM EST
WEDNESDAY FOR PAZ007>009-013>016-020>022-029-031-073>078.
OH...EXTREME COLD WARNING UNTIL 11 AM EST THIS MORNING FOR
OHZ039>041-048>050-057>059-068-069.
COLD WEATHER ADVISORY FROM 7 PM THIS EVENING TO 11 AM EST
WEDNESDAY FOR OHZ039>041-048>050-057>059-068-069.
WV...EXTREME COLD WARNING UNTIL 11 AM EST THIS MORNING FOR
WVZ001>004-012-021-509>513.
COLD WEATHER ADVISORY FROM 7 PM THIS EVENING TO 11 AM EST
WEDNESDAY FOR WVZ001>004-012-021-509>513.
EXTREME COLD WARNING UNTIL 11 AM EST WEDNESDAY FOR WVZ514.
DISCUSSION...MILCAREK
AVIATION...SHALLENBERGER/88
CLIMATE...MILCAREK
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