941
FXUS21 KWNC 121958
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EST JANUARY 12 2024
SYNOPSIS: A MAJOR ARCTIC AIR OUTBREAK ONGOING AT THE ONSET OF THE WEEK-2 PERIOD
LOOKS TO WANE ACROSS THE EASTERN CONTIGUOUS U.S. (CONUS) EARLY IN THE PERIOD. A
STORM SYSTEM EXITING THE NORTHEAST EARLY IN THE PERIOD BRINGS CHANCES OF HIGH
WINDS AND HEAVY SNOW TO PORTIONS OF THE GREAT LAKES AND NORTHEAST. ACROSS THE
WEST, A QUICK SHOT OF HEAVY PRECIPITATION, SNOW, AND HIGH WINDS ARE POSSIBLE
EARLY IN THE WEEK-2 PERIOD BEFORE THIS SYSTEM PROGRESSES EASTWARD INTO THE FOUR
CORNERS AND SOUTHERN PLAINS. THIS WILL BRING INCREASED CHANCES FOR HEAVY
PRECIPITATION TO PARTS OF THE GULF COAST BY THE MIDDLE OF THE PERIOD. IN
ALASKA, HIGH PRESSURE ACROSS THE NORTHERN HALF OF THE STATE AND LOW PRESSURE
ACROSS THE GULF OF ALASKA INCREASE CHANCES FOR STRONG GAP WINDS EARLY IN THE
PERIOD.
HAZARDS
HIGH RISK OF MUCH BELOW NORMAL TEMPERATURES FOR PORTIONS OF THE MIDDLE
MISSISSIPPI, OHIO, AND TENNESSEE VALLEYS, APPALACHIANS, AND THE SOUTHEAST, SAT,
JAN 20.
MODERATE RISK OF MUCH BELOW NORMAL TEMPERATURES FOR PORTIONS OF THE
MISSISSIPPI, TENNESSEE AND OHIO VALLEYS, APPALACHIANS, SOUTHEAST, AND
MID-ATLANTIC, SAT-SUN, JAN 20-21.
SLIGHT RISK OF MUCH BELOW NORMAL TEMPERATURES FOR MUCH OF THE CENTRAL AND
EASTERN CONUS EXCLUDING THE NORTHERN PLAINS AND SOUTHERN FLORIDA PENINSULA,
SAT-MON, JAN 20-22.
SLIGHT RISK OF HEAVY PRECIPITATION ACROSS MUCH OF CALIFORNIA, SAT-MON, JAN
20-22.
SLIGHT RISK OF HEAVY SNOW ACROSS THE SIERRA NEVADA MOUNTAINS, SAT-MON, JAN
20-22.
SLIGHT RISK OF HIGH WINDS ALONG THE WEST COAST, SAT-MON, JAN 20-22.
FLOODING POSSIBLE FOR PORTIONS OF THE NORTHERN SIERRA NEVADA AND CASCADE
MOUNTAIN FOOTHILLS.
MODERATE RISK OF HIGH WINDS OVER PORTIONS OF THE NORTHEAST, SAT-SUN, JAN 20-21.
SLIGHT RISK OF HIGH WINDS OVER PORTIONS OF THE GREAT LAKES, OHIO VALLEY,
NORTHEAST, AND NORTHERN MID-ATLANTIC, SAT-MON, JAN 20-22.
SLIGHT RISK OF HEAVY SNOW ACROSS NORTHERN PORTIONS OF THE NORTHEAST, SAT, JAN
20.
SLIGHT RISK OF HEAVY SNOW DOWNWIND OF LAKES SUPERIOR AND MICHIGAN, SAT, JAN 20.
SLIGHT RISK OF HEAVY SNOW DOWNWIND OF LAKES ERIE AND ONTARIO, SAT-SUN, JAN
20-21.
MODERATE RISK FOR HEAVY PRECIPITATION ACROSS PORTIONS OF THE TEXAS AND
LOUISIANA GULF COAST, MON-WED, JAN 22-24.
SLIGHT RISK FOR HEAVY PRECIPITATION ACROSS PORTIONS OF THE SOUTHERN PLAINS,
TENNESSEE AND LOWER MISSISSIPPI VALLEYS, AND SOUTHEAST, MON-THU, JAN 22-25.
SLIGHT RISK FOR HIGH ELEVATION SNOW ACROSS PORTIONS OF THE FOUR CORNERS REGION,
MON-WED, JAN 22-24.
SLIGHT RISK FOR HIGH WINDS MUCH OF THE SOUTHERN MAINLAND ALASKA COAST, FRI-TUE,
JAN 20-23.
DETAILED SUMMARY
FOR MONDAY JANUARY 15 - FRIDAY JANUARY 19:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR SATURDAY JANUARY 20 - FRIDAY JANUARY 26: ARCTIC COLD IS FORECAST TO BE
ENTRENCHED ACROSS MUCH OF THE EASTERN CONUS AT THE OUTSET OF WEEK-2. THERE IS
GOOD AGREEMENT AMONG THE MODELS REGARDING CONTINUED COLD AIR EARLY IN WEEK-2,
WITH THE ECMWF AND GEFS PROBABILISTIC EXTREMES TOOL (PET) DEPICTING AT LEAST A
60 PERCENT CHANCE MINIMUM TEMPERATURES FALL BELOW THE 15TH CLIMATOLOGICAL
PERCENTILE EXTENDING ACROSS THE MIDWEST AND INTO THE SOUTHEAST FOR DAY 8.
SUBZERO TEMPERATURES ARE POSSIBLE ACROSS THE MIDWEST AND OHIO VALLEY WITH PARTS
OF THE DEEP SOUTH POTENTIALLY HAVING MINIMUM TEMPERATURES LESS THAN 20 DEG F
AND SUBFREEZING TEMPERATURES POSSIBLY EXTENDING TO THE GULF COAST AND NORTHERN
FLORIDA. DUE TO THESE SIGNALS, A HIGH RISK FOR MUCH BELOW NORMAL TEMPERATURES
IS POSTED ACROSS PARTS OF THE MIDDLE MISSISSIPPI, OHIO AND TENNESSEE VALLEYS,
APPALACHIANS, AND SOUTHEAST FOR JAN 20. THE MODERATE RISK CONTINUES ACROSS
PORTIONS OF THE MISSISSIPPI, TENNESSEE, AND OHIO VALLEYS, APPALACHIANS, AND
MID-ATLANTIC JAN 20-21. THE SLIGHT RISK INCLUDES MUCH OF THE CENTRAL AND
EASTERN CONUS, WITH LOW WIND CHILLS BEING THE MAJOR CONCERN ACROSS THE NORTHERN
TIER DESPITE PROBABILITIES FOR REACHING HAZARDOUS TEMPERATURES IN THE PETS
BEING LOWER COMPARED TO FURTHER SOUTH. THIS INCLUDES ACROSS PARTS OF THE OHIO
VALLEY, MID-ATLANTIC, AND NORTHEAST WHERE SUBZERO WIND CHILLS ARE POSSIBLE
(BELOW -20 DEG F ACROSS PARTS OF INTERIOR NEW ENGLAND, THE GREAT LAKES, AND
UPPER MISSISSIPPI VALLEY). THE SLIGHT RISK IS DISCONTINUED AFTER JAN 22 AS
SIGNALS FOR HAZARDOUS COLD DECREASE DUE TO MORE RIDGING AND A POSSIBLY WARMER
PATTERN BUILDING INTO THE EAST DURING LATE-JANUARY ASSOCIATED WITH THE MJO
PROGRESSION INTO THE MARITIME CONTINENT AND WESTERN PACIFIC.
STRONG WINDS ARE LIKELY TO ACCOMPANY THE INCOMING COLD, PARTICULARLY ACROSS THE
NORTHERN TIER OF THE CONUS WHERE PRESSURE GRADIENTS ARE FORECAST TO BE HIGHER
DUE TO LOWER PRESSURE OVER SOUTHEASTERN CANADA AND HIGHER PRESSURE ACROSS THE
SOUTHEAST. THESE WINDS MAY APPROACH HAZARDOUS THRESHOLDS (GREATER THAN A 20
PERCENT CHANCE OF EXCEEDING THE 85TH CLIMATOLOGICAL PERCENTILE AND 20-MPH BASED
ON THE ECMWF PET OVER SOME AREAS), WHICH WOULD ALSO CONTRIBUTE TO THE
AFOREMENTIONED VERY LOW WIND CHILL VALUES. THE SLIGHT RISK OF HIGH WINDS IS
POSTED ACROSS PORTIONS OF THE GREAT LAKES, OHIO VALLEY, NORTHEAST, AND NORTHERN
MID-ATLANTIC FOR JAN 20-22, WITH A MODERATE RISK FOR HIGH WINDS POSTED ACROSS
THE NORTHEAST JAN 20-21 CORRESPONDING WITH WHERE THE STRONGEST PRESSURE
GRADIENT IS FORECAST. THE ELEVATED WIND SPEEDS MAY ALSO TRIGGER EPISODES OF
HEAVY LAKE EFFECT SNOW DOWNWIND OF THE GREAT LAKES GIVEN LITTLE ICE COVER AND
THE COLD AIR MASS MOVING OVERHEAD. THEREFORE, A SLIGHT RISK OF HEAVY SNOW IS
HIGHLIGHTED OVER AREAS TO THE SOUTHEAST OF LAKES MICHIGAN AND SUPERIOR FOR JAN
20 AND LAKES ERIE AND ONTARIO FOR JAN 20-21. THE ECMWF ENSEMBLE ALSO INDICATES
A SLIGHT POTENTIAL FOR A COASTAL LOW PRESSURE SYSTEM TO DEVELOP ACROSS THE
NORTHEAST, WITH SOME AREAS HAVING AT LEAST A 20 PERCENT CHANCE OF SNOWFALL
GREATER THAN 4 INCHES. THEREFORE, A SLIGHT RISK OF HEAVY SNOW HAS BEEN ADDED
ACROSS PARTS OF THE NORTHEAST FOR JAN 20, ALTHOUGH UNCERTAINTY REMAINS HIGH
GIVEN LIMITED SUPPORT FROM THE GEFS AND CANADIAN.
AT THE ONSET OF WEEK-2 A TROUGH DEVELOPING ACROSS THE NORTHEASTERN PACIFIC WITH
A STRONG RIDGE DEVELOPING ACROSS THE INTERIOR WEST BRIEFLY INCREASES CHANCES
FOR HEAVY PRECIPITATION INTO PORTIONS OF CALIFORNIA EARLY IN WEEK-2. THE GEFS
PET IS FORECASTING AT LEAST A 20% CHANCE OF 3 DAY PRECIPITATION TOTALS TO
EXCEED THE 85TH CLIMATOLOGICAL PERCENTILE AND 1 INCH. THE ECMWF PET IS MORE
ROBUST, FORECASTING A 60% CHANCE OF EXCEEDING THE 85TH PERCENTILE AND 2 INCHES
ACROSS MUCH OF CALIFORNIA. THE LARGE DISAGREEMENT AMONG THESE TOOLS IS LIKELY
RELATED TO THE STRENGTH OF THE TROUGH AND ASSOCIATED SURFACE LOW PRESSURE IN
THE GULF OF ALASKA. IF THIS STORM MATERIALIZES AS THE ECMWF FORECASTS, THIS
COULD BE A QUICK BUT MAJOR EVENT. HOWEVER, IF THE STORM DOES NOT DEVELOP, VERY
LITTLE PRECIPITATION MAY ACTUALLY OCCUR. THEREFORE, A SLIGHT RISK OF HEAVY
PRECIPITATION IS POSTED FOR MUCH OF CALIFORNIA AND SOUTHEAST OREGON FOR JAN
20-22. ASSOCIATED WITH THIS SYSTEM IS A SLIGHT RISK FOR HEAVY SNOW ACROSS
HIGHER ELEVATIONS OF THE SIERRA-NEVADA AND KLAMATH MOUNTAINS. SNOW LEVELS ARE
LIKELY TO BE HIGHER THAN NORMAL DUE TO FORECAST WARMER THAN NORMAL CONDITIONS
ACROSS THE WESTERN CONUS DURING THE WEEK-2 PERIOD. THIS MAY SET UP A RAIN ON
SNOW EVENT FOLLOWING HEAVY SNOW EVENTS PRIOR TO THE WEEK-2 PERIOD. THEREFORE A
FLOODING POSSIBLE HAZARD IS FORECAST FOR THE FOOTHILLS OF THE SIERRA NEVADA AND
CASCADE MOUNTAINS. FINALLY, A SLIGHT RISK OF HIGH WINDS IS FORECAST FOR THE
ENTIRE PACIFIC COAST AS THIS SYSTEM MOVES ASHORE, AGAIN FOR JAN 20-22.
AS THE ENERGY OF THIS SYSTEM MOVES INLAND, IT COULD BRING INCREASED CHANCES FOR
HEAVY SNOW TO THE HIGHER ELEVATIONS OF THE FOUR CORNERS REGION BY THE MIDDLE OF
THE PERIOD. THIS IS SUPPORTED BY THE GEFS AND ECMWF PETS INDICATING 3 DAY
PRECIPITATION TOTALS EXCEEDING THE 85TH PERCENTILE ACROSS THIS REGION. THE RAW
TOOLS ALSO SUPPORT THIS WITH MANY PORTIONS OF THE CENTRAL AND SOUTHERN ROCKIES
BEING HIGHLIGHTED FOR GREATER THAN 4 INCHES OF SNOW DURING THE PERIOD.
THEREFORE, A SLIGHT RISK FOR HEAVY SNOW IS POSTED FOR JAN 22-24 FOR HIGHER
ELEVATIONS OF ARIZONA, NEW MEXICO, AND COLORADO.
FURTHER EAST, AS THE COLD HIGH PRESSURE ASSOCIATED WITH THE ARCTIC AIR OUTBREAK
SHIFTS EAST AND AS THE SHORTWAVE TROUGH PUSHES EAST OUT OF THE FOUR CORNERS, A
RISK FOR HEAVY PRECIPITATION IS FORECAST ACROSS THE SOUTHERN PLAINS,
LOWER-MISSISSIPPI VALLEY, AND PARTS OF THE SOUTHEAST. THE PETS FROM THE GEFS
AND ECMWF BOTH FORECAST THAT WITHIN THIS AREA THERE IS AT LEAST A 20% CHANCE OF
THREE DAY PRECIPITATION EXCEEDING THE 85TH CLIMATOLOGICAL PERCENTILE.
MEANWHILE, ALONG THE GULF COAST OF TEXAS AND LOUISIANA, THERE IS BETTER
AGREEMENT AMONG THE PETS TODAY WITH A GREATER THAN 30% CHANCE IN THE GEFS OF
EXCEEDING THE 85TH PERCENTILE AND 1 INCH AND A 60% CHANCE IN THE ECMWF OF
PRECIPITATION EXCEEDING 2 INCHES. RAW MODEL GUIDANCE IS ALSO IN BROAD AGREEMENT
WITH THESE ENHANCED CHANCES AND IS SUPPORTED BY THE 500-HPA HEIGHT PATTERN AS
WELL. THEREFORE, A MODERATE RISK OF HEAVY PRECIPITATION IS FORECAST FROM JAN
22-24. WHILE A BROADER SLIGHT RISK ENCOMPASSING MUCH OF THE SOUTHERN PLAINS,
LOWER-MISSISSIPPI VALLEY, AND PARTS OF THE SOUTHEAST IS FORECAST FOR JAN 22-25.
IN ALASKA, ARCTIC SURFACE HIGH PRESSURE IS FORECAST TO DEVELOP ACROSS NORTHERN
PORTIONS OF THE STATE. MEANWHILE, SURFACE LOW PRESSURE IN THE GULF OF ALASKA IS
ALSO FORECAST. THIS PATTERN MAY FACILITATE STRONG GAP WINDS TO DEVELOP ACROSS
MUCH OF SOUTHERN MAINLAND ALASKA. THEREFORE A SLIGHT RISK OF HIGH WINDS IS
POSTED FROM ABOUT COLD BAY IN THE ALASKA PENINSULA EAST TO CAPE SPENCER IN
SOUTHEAST ALASKA FOR JAN 20-23.
FORECASTER: RYAN BOLT
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