223
FXUS61 KPBZ 281849
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
149 PM EST WED JAN 28 2026
WHAT HAS CHANGED
- CHANCES OF FLURRIES AND LIGHT SNOW INTO TOMORROW HAVE
INCREASED A BIT, WITH ACCUMULATIONS REMAINING UNDER AN INCH IN
MOST CASES.
- POTENTIAL FOR IMPACTS FROM AN EXPECTED WEEKEND NOR'EASTER
CONTINUE TO SLOWLY DECREASE.
KEY MESSAGES
1) VERY COLD AIRMASS CONTINUES THROUGH THE WEEKEND.
2) LIGHT SNOW AND FLURRIES ARE FORECAST INTO THURSDAY, WITH
MODEST ACCUMULATION.
2) THERE REMAINS A LOW PROBABILITY OF SNOW THIS WEEKEND IN THE
HIGH TERRAIN.
DISCUSSION
KEY MESSAGE 1...
WE CONTINUE TO FORECAST VERY COLD CONDITIONS THROUGH THE END OF
THE WEEK, WITH VALUES 20 TO 30 DEGREES BELOW CLIMATOLOGIC NORMS.
ANOTHER COLD WEATHER ADVISORY IS IN EFFECT THROUGH 11AM
THURSDAY, AS WIND CHILLS BETWEEN 5 AND 15 DEGREES BELOW ZERO ARE
FORECAST WITH HIGH CONFIDENCE. THE EXTREME COLD WARNING FOR
EASTERN TUCKER COUNTY STILL EXTENDS THROUGH 11AM THURSDAY WITH
WIND CHILLS AS LOW AS -25F.
THE COLDEST AIR TEMPERATURES ARE FORECAST FOR THURSDAY AND
FRIDAY NIGHTS, AS WEAK SURFACE RIDGING, LIGHT WIND, MORE
SCATTERED CLOUD COVERAGE, AND THE SNOW PACK COMBINE TO CREATE
IDEAL RADIATIONAL COOLING. WIDESPREAD READINGS BETWEEN ZERO AND
10 BELOW ARE FORECAST - NBM PROBABILITIES OF BELOW-ZERO READINGS
FOR BOTH NIGHTS RANGE FROM 55-65 PERCENT NEAR THE MASON-DIXON
LINE, TO 100 PERCENT NORTH OF I-80. AN IMPORTANT CONSIDERATION
TO NOTE - GIVEN THE LIGHT WIND, COLD AIR DRAINAGE INTO LOWER-
LYING RURAL LOCATIONS COULD LEAD TO LOWER TEMPERATURES THAN CAN
REASONABLY BE DEPICTED BY OUR 2.5KM GRIDDED FORECAST DATABASE.
IT WOULD NOT BE A SURPRISE TO SEE READINGS OF 20 BELOW ZERO OR
COLDER IN ISOLATED CASES.
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. ANALOGS FOR SIMILAR TEMPERATURES IN 1994,
2015, AND 2018 SHOWED WIDESPREAD IMPACTS TO INFRASTRUCTURE. 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.
THERE REMAINS SOME GOOD POTENTIAL FOR TEMPERATURE MODERATION
EARLY NEXT WEEK, AS 500MB HEIGHTS RISE FOLLOWING THE DEPARTURE
OF THE TROUGH ASSOCIATED WITH THE FORECAST ATLANTIC LOW PRESSURE
SYSTEM. STILL, CHANCES OF REACHING THE FREEZING MARK BY
WEDNESDAY NEXT WEEK ARE NOT HIGH - NBM PROBABILITIES OF THAT TOP
OUT AT 40 TO 50 PERCENT SOUTH OF I-70.
KEY MESSAGE 2...
A SHORTWAVE TROUGH SWINGS ACROSS THE UPPER OHIO VALLEY AND
CENTRAL/NORTHERN APPALACHIANS THROUGH TOMORROW. ALTHOUGH THIS
SYNOPTIC FACTOR WILL HELP TO PROVIDE SOME MODEST LIFT THROUGH
THE PERIOD, OVERALL MOISTURE REMAINS MINIMAL IN THIS FRIGID AIR
MASS, WITH PRECIPITABLE WATER TOPPING OUT RIGHT AROUND 0.1 INCH.
ALSO, MUCH OF THIS MOISTURE WILL BE PRESENT IN A RELATIVELY
THIN LAYER THAT WILL SIT JUST ABOVE THE IDEAL DENDRITIC GROWTH
ZONE. GIVEN THIS, SNOW CRYSTALS WILL REMAIN FAIRLY SMALL OVERALL
AND WILL NOT ACCUMULATE IN AN IDEAL MANNER.
SINCE THE NBM DOES NOT SHOW THIS ACTIVITY WELL, USED A
COMBINATION OF THE HREF AND WPC GUIDANCE TO PRODUCE THE SNOWFALL
FORECAST. OVERALL, FLURRIES AND LIGHT SNOW SHOWERS ARE PICTURED
THROUGH THE PERIOD, WITH ONLY A MINIMAL UPSLOPE COMPONENT TO
PROVIDE SLIGHTLY MORE COVERAGE ALONG THE RIDGES (WHERE THE DGZ
MAY ALSO INTERSECT THE TERRAIN). IT IS HERE WHERE SPOTTY
ACCUMULATION OF AN INCH MAY OCCUR OVER THE NEXT 24 HOURS, WHILE
AREAS TO THE WEST SHOULD REMAIN BELOW THAT THRESHOLD, ONLY
RECEIVING A DUSTING AT MOST IN MANY CASES. MOST OF THIS ACTIVITY
SHOULD FADE TOMORROW AFTERNOON AS THE SHORTWAVE DEPARTS.
KEY MESSAGE 3...
ENSEMBLE RUNS REMAIN NOT TOO BULLISH NOW ON IMPACTS TO OUR
REGION FROM THE EXPECTED WEEKEND NOR'EASTER. MODELS CONTINUE TO
SHOW A DIGGING EASTERN CONUS TROUGH SUPPORTING CYCLOGENESIS
SATURDAY INTO SUNDAY, BUT THE MAJORITY OF MEMBERS CONTINUE TO
INDICATE A MORE EASTWARD SURFACE LOW TRACK THAT WOULD KEEP ANY
NOTABLE ACCUMULATION WELL TO OUR EAST. A MORE FAVORABLE PATTERN
FOR SNOW FOR OUR REGION WOULD NEED TO INCLUDE AN UPPER LOW THAT
WOULD CUT OFF SOONER AND DEEPER THAN THE CURRENT CONSENSUS.
IN EXAMINING THE NBM PROBABILITY SPACE, ONE CAN NOTE A VERY GOOD
EXAMPLE OF A DISTRIBUTION WITH A LONG "TAIL." WE'LL USE EASTERN
TUCKER COUNTY TO ILLUSTRATE THIS (ALL SNOW TOTALS GIVEN BELOW IN
THE REST OF THIS PARAGRAPH ARE FOR THAT LOCATION ONLY). LOOKING
AT 48-HOUR SNOW TOTALS THROUGH 1 PM SUNDAY, THAT AREA HAS A
MEAN TOTAL OF 4 INCHES. BUT, WHEN YOU LOOK AT THE 50TH
PERCENTILE VALUES (ESSENTIALLY THE MEDIAN OF THE DISTRIBUTION),
THAT VALUE IS ZERO...AND YOU HAVE TO GO TO THE 75TH PERCENTILE
TO START TO APPROACH THE MEAN TOTALS. THIS SHOWS THAT THERE ARE
A FEW MEMBERS WITH HIGHER SNOW TOTALS SKEWING THE MEAN OF THE
DISTRIBUTION. INDEED, 90TH PERCENTILE TOTALS RISE TO A FOOT WITH
THIS SYSTEM, AND 95TH PERCENTILE FORECASTS CLIMB TO TWO FEET!
SO, THE OVERALL MESSAGE IS THIS: THERE IS A BETTER-THAN-EVEN
CHANCE OF VIRTUALLY NO SNOW FROM THIS SYSTEM ANYWHERE IN OUR
FORECAST AREA. BUT, HIGHER-END SCENARIOS (ABOUT 25 PERCENT OF
THEM) START TO BRING ADVISORY-LEVEL SNOW TO EASTERN TUCKER
COUNTY, WHILE THE WORST-CASE SCENARIOS (10 PERCENT OF THE
OVERALL MODEL RUNS) WOULD BRING SUCH SNOWS AS FAR WEST AS
MORGANTOWN AND UNIONTOWN, WITH WARNING-LEVEL SNOW IN TUCKER
COUNTY. OVERALL TRENDS FAVOR A CONTINUED DECREASE IN
PROBABILITIES OF THE HIGHER SNOW TOTALS, BUT THIS OF COURSE
WILL BE MONITORED FOR ANY CHANGES.
AVIATION /18Z WEDNESDAY THROUGH MONDAY/
KEY MESSAGES...
1) MVFR CIGS AREAWIDE THROUGH TONIGHT WITH FLURRIES AND LIGHT
SNOW SHOWERS PERSISTING
2) CIG RESTRICTIONS CONTINUE ON THURSDAY UNDER UPPER TROUGHING
------------------------------------------------------------
PASSAGE OF A MID-LEVEL TROUGH HAS PROMOTED INCREASED CLOUD
COVERAGE WITH MVFR CIGS PRIMARILY THE THEME ACROSS THE AREA. IN
ADDITION, WITH SHALLOW MOISTURE SATURATING THE DGZ AND WEAK
LIFT IN THIS LAYER, LIGHT SNOW SHOWERS WILL CONTINUE UNTIL
SUNSET AND THE FORCING DEPARTS. THESE HAVE SO FAR OVERPERFORMED
EXPECTATIONS WITH PERIODS OF IFR VISIBILITY, SO HAVE INCLUDED
TEMPO GROUPS REFLECTING SUCH CONDITIONS THIS AFTERNOON FOR ALL
SITES EXCEPT ZZV WHERE SNOW IS LESS LIKELY. WIND WILL HOLD
BETWEEN 5-10 KNOTS OUT OF THE WEST/SOUTHWEST.
FOLLOWING THE PASSAGE OF THE WAVE, MVFR CIGS ARE LIKELY TO HOLD
ON OVERNIGHT WITH 60-80% CHANCE AS MOISTURE TRAPS IN THE
BOUNDARY LAYER. FKL/DUJ FEATURE AROUND A 50-60% CHANCE OF IFR
OVERNIGHT SUPPORTED BY HRRR/RAP SOUNDINGS. AGAIN, CAN'T RULE OUT
SOME FLURRIES CONTINUING OVERNIGHT IN A MARGINALLY UNSTABLE,
SATURATED PROFILE THROUGH THE DGZ, BUT LACK OF FORCING SHOULD
KEEP ANYTHING LIGHT. WIND WILL RELAX A BIT TO AROUND 5 KNOTS
AREAWIDE.
OUTLOOK...
PERSISTENT EAST COAST TROUGHING WILL PROVIDE CONTINUED ROUNDS OF
LIGHT SNOW, ANOTHER LIKELY ON THURSDAY AFTERNOON WITH A LULL ON
FRIDAY, AND PERIODIC CEILING RESTRICTIONS THROUGH THE WEEKEND.
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 FRIDAY 1/30:
PITTSBURGH, PA (DAILY LOW MIN TEMP RECORD) -5F (2019)
PITTSBURGH, PA (DAILY LOW MAX TEMP RECORD) 10F (1977)
DUBOIS, PA (DAILY LOW MIN TEMP RECORD) -10F (2019)
WHEELING, WV (DAILY LOW MIN TEMP RECORD) -5F (2019)
WHEELING, WV (DAILY LOW MAX TEMP RECORD) 12F (1934)
ZANESVILLE, OH (DAILY LOW MIN TEMP RECORD) -4F (2019)
DAILY COLD RECORDS AT RISK OF BEING BROKEN SATURDAY 1/31:
PITTSBURGH, PA (DAILY LOW MIN TEMP RECORD) -5F (2019)
MORGANTOWN, WV (DAILY LOW MAX TEMP RECORD) 12F (1965)
WHEELING, WV (DAILY LOW MAX TEMP RECORD) 12F (2019)
WHEELING, WV (DAILY LOW MIN TEMP RECORD) -8F (1948)
NEW PHILADELPHIA, OH (DAILY LOW MIN TEMP RECORD) -6F (2019)
ZANESVILLE, OH (DAILY LOW MAX TEMP RECORD) 11F (2019)
ZANESVILLE, OH (DAILY LOW MIN TEMP RECORD) -8F (1955)
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...COLD WEATHER ADVISORY FROM 7 PM THIS EVENING TO 11 AM EST
THURSDAY FOR PAZ007>009-013>016-020>022-029-031-073>078.
OH...COLD WEATHER ADVISORY FROM 7 PM THIS EVENING TO 11 AM EST
THURSDAY FOR OHZ039>041-048>050-057>059-068-069.
WV...COLD WEATHER ADVISORY FROM 7 PM THIS EVENING TO 11 AM EST
THURSDAY FOR WVZ001>004-012-021-509>513.
EXTREME COLD WARNING UNTIL 11 AM EST THURSDAY FOR WVZ514.
DISCUSSION...CL/MILCAREK
AVIATION...MLB
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