174
FXUS61 KPBZ 170201
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
901 PM EST THU JAN 16 2025
SYNOPSIS
SNOW TAPERS OFF OVERNIGHT AS LOW PRESSURE DEPARTS. A DRY FRIDAY
IS FORECAST AS HIGH PRESSURE BRIEFLY VISITS. ANOTHER SYSTEM
WILL CROSS THIS WEEKEND BEFORE A SIGNIFICANT ARCTIC OUTBREAK
BRINGS FRIGID TEMPERATURES NEXT WEEK.
NEAR TERM /UNTIL 6 AM FRIDAY MORNING/
KEY MESSAGES:
- A FEW INCHES OF ADDITIONAL SNOW ACCUMULATION IS EXPECTED
OVERNIGHT IN THE RIDGES, WITH AN INCH OR LESS ELSEWHERE.
- SEASONABLE OVERNIGHT LOWS - THE WARMEST IN TWO WEEKS, IN SOME
CASES.
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SNOW HAS TAPERED WEST OF THE RIDGES AS THE MAIN SHORTWAVE PULLS
EAST AND AS LIFT AND MOISTURE IN THE DENDRITIC GROWTH ZONE
TAPERS OFF. SNOW SHOWERS WILL LINGER IN W-NW FLOW THROUGH
TONIGHT. ADDITIONAL ACCUMULATION OUTSIDE OF THE RIDGES SHOULD
REMAIN AN INCH OR LESS, WITH A FEW MORE INCHES POSSIBLE ON THE
HIGHER PEAKS IN THE CURRENT WINTER STORM WARNING AREA, WHICH
WILL BE CONTINUED THROUGH THE NIGHT.
WITH THE ACCUMULATING SNOW THREAT ENDING, ELECTED TO CANCEL THE
WINTER WEATHER ADVISORY FOR EASTERN OHIO AND THE WEST VIRGINIA
PANHANDLE, WHILE MAINTAINING IT IN SOUTHWEST PA AND THE REST OF
NORTHERN WEST VIRGINIA IN COLLABORATION WITH SURROUNDING
OFFICES. AS SNOW TAPERS OFF AND MOISTURE DECREASES, CANNOT
TOTALLY RULE OUT A PATCHY FREEZING DRIZZLE CHANCE, MAINLY IN
EASTERN OHIO. HOWEVER, THE PBZ 00Z SOUNDING, MODEL SOUNDINGS,
AND CURRENT IR LOOPS MAINTAIN CLOUD TOP TEMPERATURES MOSTLY
ABOVE -10C, SO THINK THAT THIS THREAT IS CURRENTLY LOW.
BY SUNRISE, ISOLATED TO SCATTERED SNOW SHOWERS WILL GENERALLY
REMAIN NORTH OF PITTSBURGH AND ALONG THE RIDGES. LOW
TEMPERATURES WILL BE SEASONABLE, AND IN SOME CASES, MAY BE THE
WARMEST SUCH VALUES SINCE JANUARY 3RD.
SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/
KEY MESSAGES:
- GRADUALLY WARMING TEMPERATURES INTO THE WEEKEND.
- CONFIDENCE IS HIGH THAT A LOW PRESSURE SYSTEM WILL BRING A
ROUND OF RAIN/WINTRY MIX/SNOW TO THE AREA ON SATURDAY
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LINGERING SNOW IS POSSIBLE IN NORTHWEST FLOW EARLY FRIDAY, BUT
THIS SHOULD END SHORTLY AFTER SUNRISE AS RIDGING QUICKLY BUILDS
ACROSS THE REGION. AS WINDS SHIFT FROM THE SOUTH, EXPECTED NEAR
OR SLIGHTLY ABOVE AVERAGE TEMPERATURES FRIDAY AFTERNOON.
A NEW LOW PRESSURE SYSTEM EXPECTED TO ENTER THE REGION EARLY
SATURDAY MORNING. DUE TO DEEP WARM SOUTHWEST FLOW, EXPECTED
MIXED PRECIPITATION EMBEDDED WITHIN THIS DISTURBANCE. INITIAL
PRECIP TYPE IS GOING TO DEPEND ON HOW FAST THE LOW-LVL WARM AIR
ADVANCES AND THE DEPTH. EVEN IF THERE IS SNOW, THE RATIOS WILL
VERY LOW TO CREATE IMPACTS. THE PROBABILITY OF 1 INCH OF SNOW
WITH THE LATEST GUIDANCE OF THE NBM RANGES FROM 30% TO 45%
NORTH OF I-80%. PROBABILITIES CAN INCREASE OR DECREASE
SIGNIFICANTLY BASED ON WHERE THE FREEZING LINE RESIDES.
BY LATE SATURDAY NIGHT, AN APPROACHING COLD FRONT FROM THE WEST
WILL CHANGE RAIN TO SNOW.
LONG TERM /SUNDAY THROUGH THURSDAY/
KEY MESSAGES:
- SNOW SHOWERS CONTINUE ON SUNDAY AND MONDAY IN NORTHWEST FLOW.
- ARCTIC OUTBREAK WITH DANGEROUSLY COLD TEMPERATURES AND WIND
CHILLS LIKELY NEXT WEEK.
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LIGHT SNOW SHOWERS MAY CONTINUE WITH NORTHWEST FLOW ON SUNDAY
AND MONDAY, BUT THIS WILL LARGELY DEPEND ON ICE-FREE LAKE
SURFACES. AS LAKE ERIE NEARS FULL ICE COVERAGE, MOISTURE
AVAILABILITY MAY BE LIMITED.
HIGH TEMPERATURES ON SUNDAY WILL DROP BACK INTO THE 20S, WITH
COLDER WEATHER STILL TO COME.
.. EXTREME COLD MONDAY THROUGH WEDNESDAY ..
CONFIDENCE REMAINS HIGH IN A SIGNIFICANT ARCTIC OUTBREAK EARLY NEXT
WEEK. EXTREMELY LOW TEMPERATURES AND WIND CHILL TEMPERATURES ARE
EXPECTED TO IMPACT THE REGION MONDAY THROUGH WEDNESDAY. ARCTIC AIR
WILL DIP DOWN OUT OF FAR NORTHERN CANADA ACROSS THE EASTERN UNITED
STATES BEGINNING SUNDAY NIGHT.
CLUSTER ANALYSIS CONTINUES TO INDICATE A DEEPER TROUGH ACROSS THE
EASTERN UNITED STATES DURING THIS TIME PERIOD, CONTINUING THE
DEEPENING TREND SEEN IN THE PREVIOUS 24 HOURS. THIS CONTINUED
DEEPENING RAISES CONFIDENCE IN A COLDER SOLUTION ACROSS THE REGION.
LONG-RANGE GUIDANCE (NAEFS) HAS 850MB AND 700 MB TEMPERATURES EARLY
NEXT WEEK NEAR THE 1ST PERCENTILE (TEMPERATURES THIS TIME OF
YEAR ARE WARMER THAN THIS 99% OF THE TIME).
NBM MEAN HIGH TEMPERATURES EARLY NEXT WEEK CURRENTLY SIT IN THE LOW
SINGLE DIGITS. GROWING CONFIDENCE IN A COLDER SOLUTION WOULD LEAN
TOWARDS HIGH TEMPERATURES BETWEEN THIS AND A REASONABLE COLDEST
SOLUTION JUST NORTH OF 0 DEGREES. THE COLDER END OF GUIDANCE FOR LOW
TEMPERATURES CURRENTLY EYES THE MINUS TEENS. PROBABILITIES OF WIND
CHILL TEMPERATURES LESS THAN 0 DEGREES ARE ABOVE 90% FROM EARLY
MONDAY MORNING THROUGH MIDDAY WEDNESDAY.
THE TIME TO BEGIN PREPARING IS 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. IT
IS ENCOURAGED TO BRING MOVABLE PLANTS INDOORS. EXTREME CARE IS
ENCOURAGED FOR THE PROTECTION OF PETS AND ANIMALS. RESCHEDULING ANY
EVENTS, ESPECIALLY OUTDOOR EVENTS, IS ENCOURAGED.
CLUSTERED MODELS INDICATE THE TROUGH MOVES NORTH INTO CANADA ON
WEDNESDAY AND TEMPERATURES CLIMB BUT ARE LIKELY TO REMAIN BELOW
AVERAGE FOR THIS TIME OF YEAR THROUGH THE END OF THE WEEK. WITH
CONTINUED TEMPERATURES WELL BELOW FREEZING, RIVER ICE GROWTH IS
EXPECTED TO CONTINUE ACROSS THE REGION.
AVIATION /02Z FRIDAY THROUGH TUESDAY/
SNOW HAS BEGUN TO TAPER OFF FROM WEST TO EAST THIS EVENING AS
DRIER MID-LEVEL AIR EVIDENT ON WATER VAPOR IMAGERY ADVECTS IN.
THE MOISTURE IN THE DENDRITIC GROWTH ZONE HAS SHALLOWED AND THE
SHORTWAVE IS EXITING, SO SUPPORT FOR ANY REMAINING LIGHT SNOW
SHOWERS IS WANING. VISIBILITY WILL INCREASE AREAWIDE AS A
RESULT, AND UPSTREAM OBSERVATIONS INDICATE THAT A SHALLOW LOW-
LEVEL MOIST LAYER WILL HOLD IN PLACE OVERNIGHT WITH CIGS
HOVERING AROUND LOW END MVFR. THE EXCEPTION WILL BE LBE AND DUJ
WHERE SNOW WILL CONTINUE TO RESULT IN IFR CONDITIONS FOR THE
NEXT COUPLE HOURS BEFORE WINDING DOWN THERE AS WELL.
PROBABILITIES FOR MVFR REMAIN HIGH AT 80+% THROUGH THE OVERNIGHT
HOURS WITH IFR PROBS HIGHEST AT FKL/DUJ, SO HAVE ERRED ON THE
MORE PESSIMISTIC SIDE UP THAT WAY AND INCLUDED PREVAILING IFR
CIGS. IMPROVEMENT WON'T BE SEEN UNTIL FRIDAY AFTERNOON WHEN A
RIDGE BUILDS OVERHEAD AND DRIER AIR CLEARS OUT THE LINGERING
MOISTURE IN SOUTHERLY LOW-LEVEL FLOW, AND CONDITIONS WILL
IMPROVE FROM SOUTH TO NORTH. PROBS FOR MVFR DROP OFF AT MGW
AFTER 16Z, PIT AFTER 20Z, AND LIKELY NOT TO FKL/DUJ IN THIS TAF
PERIOD.
WIND WILL SETTLE OVERNIGHT TO AROUND 5-8 KNOTS AND GRADUALLY
BACK WEST AND EVENTUALLY SOUTH OF WEST BY FRIDAY AFTERNOON.
MIXING WILL INCREASE SUSTAINED WIND BACK TOWARD 10 KNOTS WITH
PERIODIC GUSTS TO 15-20 POSSIBLE. A PERIOD OF LLWS IS ALSO
POSSIBLE FRIDAY NIGHT, JUST AT THE END OF THE CURRENT PIT TAF,
WITH DECOUPLING AND A 30-40 KNOT LOW LEVEL JET OVERHEAD.
OUTLOOK...
ANOTHER SYSTEM BRINGS RESTRICTIONS AND RAIN/SNOW BACK TO THE
AREA SATURDAY THROUGH THE WEEKEND. A STRONG ARCTIC FRONT WILL
BRING BITTER COLD TEMPERATURES NEAR OR BELOW ZERO TO THE AREA
MONDAY AND TUESDAY.
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...WINTER WEATHER ADVISORY UNTIL 4 AM EST FRIDAY FOR PAZ007>009-
013>016-020>022-029-031-073-075-077-078.
WINTER STORM WARNING UNTIL 7 AM EST FRIDAY FOR PAZ074-076.
OH...NONE.
WV...WINTER WEATHER ADVISORY UNTIL 4 AM EST FRIDAY FOR WVZ021-509-
510.
WINTER STORM WARNING UNTIL 7 AM EST FRIDAY FOR WVZ511>514.
SYNOPSIS...RACKLEY
NEAR TERM...CL/AK
SHORT TERM...HEFFERAN
LONG TERM...RACKLEY/AK
AVIATION...CERMAK/MLB
CLIMATE...MILCAREK
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