966
FXUS61 KPBZ 201146
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
646 AM EST MON JAN 20 2025
SYNOPSIS
STRONG COLD ADVECTION WILL CREATE A MULTIPLE DAY PERIOD OF NEAR
SINGLE DIGIT AIR TEMPERATURE WITH PERIODS OF POTENTIALLY DANGEROUS
SUB FREEZING WIND CHILLS. THIS COLD PERIOD WILL ALSO FEATURE DRY
ADVECTION, MEANING VERY LIMITED PRECIPITATION CHANCES AND
POTENTIAL FOR NOTABLE FALLS IN DAYTIME HUMIDITY MINIMUMS.
NEAR TERM /UNTIL 6 PM THIS EVENING/
KEY MESSAGES:
- TRANSITION TO SCATTERED SNOW SHOWERS THIS MORNING WITH THE
PASSAGE OF AN ARCTIC FRONT.
- COMBINATION OF COLD AIR AND GUSTY WIND WILL CREATE NEGATIVE
WIND CHILLS.
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LAKE ENHANCED SNOW SHOWERS AND BLOWING SNOW IN THE WAKE OF THE
ARCTIC FRONT WILL CONTINUE FOR A PORTION OF THE MORNING OVER
PORTIONS OF WESTERN PA AND THE HIGHER TERRAIN. LOW VISIBILITY
IN SNOW SHOWERS REMAINS POSSIBLE WHILE NEAR SINGLE DIGIT
TEMPERATURES ENSURE FALLING SNOW CAN ACCUMULATE ON UNTREATED
ROADWAYS. MOTORISTS SHOULD BE PREPARED FOR CHANGING VISIBILITY
AND ROAD CONDITIONS IF OUT AND ABOUT DURING THE MORNING COMMUTE.
A WINTER WEATHER ADVISORY AND WINTER STORM WARNING FOR THE
RIDGES REMAINS IN EFFECT UNTIL 9AM THIS MORNING. DRY ADVECTION
AND INCREASING SUBSIDENCE WILL AID SHOWER DISSIPATION THROUGH
THE EARLY AFTERNOON WHILE BACKING BOUNDARY LAYER WINDS SHUNT
LAKE STREAMERS NORTH OF THE REGION.
COLD ADVECTION AND BREEZY WIND FROM DEEPER MIXING WILL CREATE
NEGATIVE WIND CHILLS DURING THE DAY. THOUGH INCREASING
SUBSIDENCE AND DRY ADVECTION WILL CLEAR CLOUDS, LITTLE DIURNAL
HEATING WILL KEEP DAYTIME AIR TEMPERATURE NEAR OR BELOW 10
DEGREES AND NEGATIVE WIND CHILLS.
SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/
KEY MESSAGES:
- ARCTIC OUTBREAK WITH DANGEROUSLY COLD TEMPERATURES AND WIND CHILLS.
- EXTREME COLD WARNING FOR RIDGES AND ADVISORY FOR LOWLANDS IN
EFFECT.
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EXTREME COLD MONDAY NIGHT THROUGH WEDNESDAY MORNING...
DANGEROUSLY COLD TEMPERATURES ARE EXPECTED THROUGHOUT THE SHORT TERM
PERIOD AS AN ANOMALOUSLY DEEP TROUGH OVER EASTERN NORTH AMERICA
OPENS THE DOOR FOR ARCTIC AIR TO MAKE ITS WAY FROM NORTHERN CANADA
INTO THE EASTERN CONUS. LOCALLY, TEMPERATURES WILL HOVER 20 TO 25
DEGREES BELOW NORMAL FOR THIS TIME OF YEAR, WITH TUESDAY MORNING
STARTING OUT NEAR OR SLIGHTLY BELOW ZERO, INCREASING TO THE UPPER
SINGLE DIGITS TO LOW TEENS TUESDAY AFTERNOON, AND THEN PLUMMETING TO
AROUND -10 DEGREES TUESDAY NIGHT. EXTREME COLD WARNINGS ARE IN
EFFECT FOR THE RIDGES OF SOUTHWEST PA AND NORTHERN WV WHERE WIND
CHILLS WILL PERIODICALLY DIP TO -20 TO -25 DEGREES. A COLD WEATHER
ADVISORY IS IN EFFECT FOR THE REST OF THE AREA WITH WIND CHILLS IN
THE -10 TO -20 DEGREE RANGE. HOWEVER, WE WILL NEED TO MONITOR TRENDS
FOR LOW TEMPERATURES AND WIND CHILLS TUESDAY NIGHT INTO EARLY
WEDNESDAY MORNING WHEN SOME LOWLAND AREAS COULD EXCEED EXTREME COLD
WARNING CRITERIA (-20 DEGREES SOUTH OF I-80, -25 DEGREES NORTH OF
THE INTERSTATE) AND UPGRADES MAY BE NEEDED. FLURRIES WILL BE
POSSIBLE DURING THE DAY TUESDAY IF THERE IS ENOUGH LOW-LEVEL
MOISTURE, THOUGH WITH LITTLE TO NO ACCUMULATION.
WE RECOMMEND BEGINNING TO PREPARE FOR THESE COLD CONDITIONS NOW.
UNPROTECTED PIPES CAN FREEZE AND BURST. PROLONGED EXPOSURE TO THE
COLD MAY LEAD TO HYPOTHERMIA. FROSTBITE CAN OCCUR IN AS LITTLE AS 30
MINUTES FOR EXPOSED SKIN. CHECK IN ROUTINELY WITH VULNERABLE FRIENDS
AND FAMILY. BRING MOVABLE PLANTS INDOORS. EXTREME CARE IS ENCOURAGED
FOR THE PROTECTION OF PETS AND ANIMALS. RESCHEDULING ANY EVENTS,
ESPECIALLY THOSE TAKING PLACE OUTDOORS, IS ALSO ENCOURAGED.
LONG TERM /WEDNESDAY THROUGH SUNDAY/
KEY MESSAGES:
- THERE WILL BE SOME WARMING BY THE END OF THE WEEK BUT
TEMPERATURES REMAIN BELOW NORMAL THROUGH AT LEAST SATURDAY.
- PRECIPITATION CHANCES MAY INCREASE FRIDAY INTO THE WEEKEND AS
ANOTHER UPPER TROUGH APPROACHES FROM THE WEST.
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VERY COLD TEMPERATURES HANG ON THROUGH WEDNESDAY NIGHT, WITH
HIGHS WEDNESDAY AFTERNOON IN THE UPPER SINGLE DIGITS TO LOW
TEENS AND NIGHTTIME LOWS IN THE LOWER SINGLE DIGITS TO NEAR
ZERO (WIND CHILLS NEAR OR SLIGHTLY BELOW ZERO). GRADUAL WARMING
IS EXPECTED THEREAFTER TO CLOSE THE WEEK AS GLOBAL ENSEMBLES
ARE IN FAIR AGREEMENT THAT THE EASTERN CONUS TROUGH DEPARTS AND
WE SEE WEAK HEIGHT RISES IN RESPONSE TO ANOTHER UPSTREAM TROUGH
DIGGING INTO THE CENTRAL CONUS. TEMPERATURES REBOUND INTO THE
20S FRIDAY AND 30S NEXT WEEKEND. DEPENDING ON THE EVENTUAL
PROGRESSION OF THE UPSTREAM TROUGH, THIS WARMING COULD ALSO BE
ACCOMPANIED BY A ROUND OF INCREASING PRECIP CHANCES.
AVIATION /12Z MONDAY THROUGH FRIDAY/
MORNING LAKE ENHANCED SHOWERS ARE EXPECTED TO TAPER OFF (WHILE
LIFTING SLIGHTLY NE) BY THIS AFTERNOON AS DRY ADVECTION AND
SUBSIDENCE INCREASES, BUT BRIEF IFR VSBYS COULD STILL DEVELOP
IN THESE BANDS. OTHERWISE, SCATTERED TO BROKEN MVFR TO LOW VFR
STRATOCU ARE EXPECTED (WITH SOME REDEVELOPMENT POSSIBLE BETWEEN
14Z-18Z) AMID STRONG COLD ADVECTION BEFORE SUBSIDENCE CLEARS
STRATUS W TO E BY TONIGHT.
STEEP LAPSE RATES AND RESIDUAL PRESSURE GRADIENTS WILL YIELD
GUSTS BETWEEN 15-25KTS WITH WIND EXHIBITING A SLIGHT BACKING
FROM THE WNW TO THE W. THERE IS HIGH CONFIDENCE (80+%
PROBABILITY OF VFR) WITH LIGHT WSW WIND OVERNIGHT.
OUTLOOK...
A REINFORCING TROUGH RETURNS MVFR CIG RESTRICTION POTENTIAL
TUESDAY (60-80% PROBABILITY OF RECURRENCE) ALONG WITH SCATTERED
LIGHT AFTERNOON SNOW SHOWERS. VFR IS LIKELY (NEAR 100%
PROBABILITY) WEDNESDAY AS SURFACE HIGH PRESSURE SITS OVER THE
REGION. RESTRICTION AND PRECIPITATION CHANCES INCREASE FRIDAY
WITH THE LIKELY APPROACH/PASSAGE OF THE NEXT UPPER LEVEL TROUGH.
CLIMATE
A PERIOD OF ANOMALOUSLY COLD WEATHER IS EXPECTED TO PASS MONDAY
THROUGH WEDNESDAY THAT WILL CHALLENGE MANY STANDING JANUARY
TEMPERATURE RECORDS. ATTACHED BELOW ARE THE STANDING
CLIMATOLOGY FOR LOCAL SITES. PITTSBURGH HAS A FULL RECORD,
WHILE OTHER SITES ARE PARTIAL RECORDS AND MAY NOT BE FULLY
REFLECTIVE OF HISTORICAL TEMPERATURES:
JANUARY 20TH: HIGH MINIMUM LOW MINIMUM
PITTSBURGH, PA 1F (1985) -18F (1985)
WHEELING, WV 13F (1940) -1F (1940)
MORGANTOWN, WV 3F (1985) -17F (1985)
NEW PHILADELPHIA, OH -3F (1994) -22F (1994)
ZANESVILLE, OH -2F (1985) -17F (1985)
DUBOIS, PA -2F (1985) -19F (1985)
JANUARY 21ST: HIGH MINIMUM LOW MINIMUM
PITTSBURGH, PA 5F (1984) -18F (1985)
WHEELING, WV 12F (2000) -2F (1924)
MORGANTOWN, WV 2F (1985) -18F (1985)
NEW PHILADELPHIA, OH -8F (1985) -19F (1985)
ZANESVILLE, OH 7F (1985) -22F (1984)
DUBOIS, PA 0F (1985) -22F (1985)
JANUARY 22ND: HIGH MINIMUM LOW MINIMUM
PITTSBURGH, PA 10F (1961) -14F (1936)
WHEELING, WV 11F (2014) -4F (2014)
MORGANTOWN, WV 11F (2014) -5F (1984)
NEW PHILADELPHIA, OH 5F (1984) -15F (1994)
ZANESVILLE, OH 13F (2014) -11F (2011)
DUBOIS, PA 8F (2013) -11F (1984)
BELOW IS THE LOWEST DAILY HIGH AND DAILY LOW TEMPERATURES OF THE
21ST CENTURY. THIS ENCOMPASSES ALL DAYS OF ALL MONTHS RUNNING
FROM JANUARY 2000 TO PRESENT:
HIGH MINIMUM LOW MINIMUM
PITTSBURGH, PA 4F (01/07/2014) -10F (01/17/2009)
(02/20/2015)
WHEELING, WV 5F (01/07/2014) -10F (01/07/2014)
MORGANTOWN, WV 7F (01/07/2014) -9F (01/28/2014)
(01/28/2014) (01/29/2014)
NEW PHILADELPHIA, OH 6F (01/16/2009) -18F (01/28/2014)
(01/28/2014)
(02/15/2015)
ZANESVILLE, OH 6F (01/28/2014) -20F (01/29/2014)
DUBOIS, PA 0F (01/07/2014) -17F (02/16/2015)
IN ADDITION, PITTSBURGH HAS NOT SEEN A DAYTIME HIGH BELOW 4F
SINCE JANUARY OF 1994. PITTSBURGH HAS ALSO HAS NOT SEEN 2
CONSECUTIVE DAYS OF HIGH TEMPERATURES LESS THAN 10F SINCE
JANUARY OF 1997. IF YOU EXTEND THIS STATISTIC TO 3 DAYS, YOU
WOULD HAVE TO GO BACK TO FEBRUARY 1899.
THE LAST TIME PITTSBURGH'S MINIMUM TEMPERATURE WAS LESS THAN OR
EQUAL TO -5F WAS DECEMBER 2022. LAST TIME IT WAS BELOW OR EQUAL
TO -10F WAS FEBRUARY 2015. FOR 2 CONSECUTIVE DAYS OF LOWS LESS
THAN OR EQUAL -10F, YOU WOULD HAVE TO GO BACK TO JANUARY OF
1994.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...COLD WEATHER ADVISORY UNTIL 1 PM EST WEDNESDAY FOR PAZ007>009-
013>016-020>022-029-031-073-075-077.
WINTER WEATHER ADVISORY UNTIL 9 AM EST THIS MORNING FOR PAZ031-
073-075-078.
WINTER STORM WARNING UNTIL 9 AM EST THIS MORNING FOR PAZ074-
076.
EXTREME COLD WARNING UNTIL 1 PM EST WEDNESDAY FOR PAZ074-076-
078.
OH...COLD WEATHER ADVISORY UNTIL 1 PM EST WEDNESDAY FOR OHZ039>041-
048>050-057>059-068-069.
WV...COLD WEATHER ADVISORY UNTIL 1 PM EST WEDNESDAY FOR WVZ001>004-
012-021-509>511.
WINTER WEATHER ADVISORY UNTIL 9 AM EST THIS MORNING FOR WVZ012-
021-509.
WINTER STORM WARNING UNTIL 9 AM EST THIS MORNING FOR
WVZ510>514.
EXTREME COLD WARNING UNTIL 1 PM EST WEDNESDAY FOR WVZ512>514.
SYNOPSIS...FRAZIER
NEAR TERM...MILCAREK
SHORT TERM...CERMAK/SHALLENBERGER
LONG TERM...CERMAK/SHALLENBERGER/LUPO
AVIATION...FRAZIER
CLIMATE...
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