177
FXUS21 KWNC 151916
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EST JANUARY 15 2025
SYNOPSIS: MID-LEVEL LOW PRESSURE ACROSS THE EASTERN CONTIGUOUS U.S. (CONUS) IS
PREDICTED TO CONTINUE TO BRING AN INCREASED LIKELIHOOD OF HAZARDOUS COLD
TEMPERATURES FROM THE END OF WEEK-1 INTO THE BEGINNING OF WEEK-2 TO PARTS OF
THE SOUTH-CENTRAL AND EASTERN CONUS. TEMPERATURES ARE ANTICIPATED TO MODERATE
AS MID-LEVEL HIGH PRESSURE BUILDS ACROSS THE EAST BY THE MIDDLE OF THE PERIOD.
SURFACE HIGH PRESSURE IS PREDICTED TO BUILD OVER THE GREAT BASIN WITH SURFACE
LOW PRESSURE DEVELOPING ALONG CENTRAL AND SOUTHERN COASTAL CALIFORNIA
INCREASING CHANCES FOR ENHANCED WIND SPEEDS ACROSS PARTS OF ARIZONA AND
SOUTHERN CALIFORNIA, WHICH COULD PROLONG THE RISK OF WILDFIRES IN THE REGION.
SANTA ANA WINDS ARE MOST LIKELY FOR THE BEGINNING OF WEEK-2, WITH WINDS HAVING
A MORE ONSHORE COMPONENT ASSOCIATED WITH MID-LEVEL LOW PRESSURE BY THE MIDDLE
OF THE PERIOD. A SERIES OF SURFACE LOWS AND ASSOCIATED FRONTS PREDICTED FOR THE
SOUTHEASTERN CONUS AND MID-ATLANTIC MAY LEAD TO PERIODS OF HEAVY PRECIPITATION
ACROSS PARTS OF THE GULF COAST STATES AND THE MID-ATLANTIC, WITH THE POTENTIAL
FOR SOME OF THIS TO FALL IN THE FORM OF FROZEN PRECIPITATION. MID-LEVEL HIGH
PRESSURE IS PREDICTED FOR ALASKA DURING WEEK-2, FAVORING ABOVE NORMAL
TEMPERATURES. NO HAZARDS ARE DESIGNATED FOR THE STATE AT THIS TIME.
HAZARDS
MODERATE RISK OF MUCH BELOW NORMAL TEMPERATURES FOR PARTS OF THE SOUTHERN
PLAINS, LOWER MISSISSIPPI AND TENNESSEE VALLEYS, MID-ATLANTIC, APPALACHIANS,
AND SOUTHEAST, THU-FRI, JAN 23-24.
SLIGHT RISK OF MUCH BELOW NORMAL TEMPERATURES FOR AREAS EAST OF THE ROCKIES
EXCLUDING THE NORTHERN PLAINS AND UPPER MISSISSIPPI VALLEY, THU-SAT, JAN 23-25.
SLIGHT RISK OF PERIODIC HEAVY PRECIPITATION FOR PORTIONS OF THE MID-ATLANTIC
AND GULF COAST STATES, THU-WED, JAN 23-29.
MODERATE RISK OF PERIODS OF HIGH WINDS ACROSS COASTAL PORTIONS OF SOUTHERN
CALIFORNIA, THU-SAT, JAN 23-25.
SLIGHT RISK OF PERIODS OF HIGH WINDS FOR PARTS OF THE SOUTHWEST AND SOUTHERN
CALIFORNIA, THU-WED, JAN 23-29.
DETAILED SUMMARY
FOR SATURDAY JANUARY 18 - WEDNESDAY JANUARY 22:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR THURSDAY JANUARY 23 - WEDNESDAY JANUARY 29: MULTIPLE MODEL ENSEMBLE MEANS
CONTINUE TO DEPICT AMPLIFIED MID-LEVEL LOW PRESSURE LINGERING OVER THE EASTERN
HALF OF THE CONUS FROM THE END OF WEEK-1 INTO THE BEGINNING OF WEEK-2. HOWEVER,
THERE IS SIGNIFICANT UNCERTAINTY REGARDING THE LOCATION AND AMPLITUDE OF
TROUGHING ACROSS THE CENTRAL AND WESTERN CONUS THROUGHOUT THE PERIOD AS THE
MID-LEVEL RIDGE RETROGRADES AND WEAKENS OVER THE NORTH PACIFIC. THE ECENS AND
CMCE ENSEMBLE MEANS CONTINUE TO INDICATE A MUCH MORE AMPLIFIED TROUGH EXTENDING
FROM THE NORTH-CENTRAL CONUS TO THE SOUTHWEST, WHEREAS THE GEFS FAVORS A MUCH
WEAKER PATTERN WITH THE TROUGH AXIS EXTENDING TO THE FOUR CORNERS REGION. THESE
MODEL DIFFERENCES TRANSLATE TO INCREASED UNCERTAINTY REGARDING THE POTENTIAL
FOR ANOMALOUSLY COLDER TEMPERATURES ACROSS THE WESTERN CONUS (ECENS AND
CANADIAN WOULD BE MORE SUPPORTIVE THAN THE GEFS OF COLDER TEMPERATURES).
WITH MODELS CONTINUING TO FAVOR MID-LEVEL TROUGHING OVER THE EAST SHIFTING OFF
THE COAST AND WEAKENING INITIALLY IN THE PERIOD, THE HIGH RISK OF MUCH BELOW
NORMAL TEMPERATURES IS NO LONGER IN TODAY’S OUTLOOK AND THE SPATIAL COVERAGE
FOR THE MODERATE AND SLIGHT RISKS ARE SIGNIFICANTLY REDUCED. A MODERATE RISK
(40-60% CHANCE) OF MUCH BELOW NORMAL TEMPERATURES IS DESIGNATED FOR PARTS OF
THE SOUTHERN PLAINS, LOWER MISSISSIPPI AND TENNESSEE VALLEYS, MID-ATLANTIC,
APPALACHIANS, AND SOUTHEAST, JAN 23-24. THE ECENS, GEFS, AND CMCE PROBABILISTIC
EXTREMES TOOLS SHOW AT LEAST A 40% CHANCE OF MINIMUM TEMPERATURES FALLING TO
THE LOWEST 15TH PERCENTILE CLIMATOLOGICALLY FOR THESE RISK AREAS. A BROADER
AREA OF SLIGHT RISK (20-40%) IS HIGHLIGHTED ACROSS AREAS EAST OF THE ROCKIES
EXCLUDING THE NORTHERN PLAINS AND UPPER MISSISSIPPI VALLEY, JAN 23-25.
SUB-FREEZING TEMPERATURES ARE PREDICTED ACROSS THE SOUTH, WHILE MUCH OF THE
NORTHEASTERN CONUS IS PREDICTED TO EXPERIENCE TEMPERATURES FALLING BELOW 10 DEG
F, WITH LOWER WIND CHILL VALUES POSSIBLE FOR MANY AREAS.
A SERIES OF SURFACE LOWS AND ASSOCIATED FRONTS ARE PREDICTED FOR THE
SOUTHEASTERN CONUS AND MID-ATLANTIC DURING WEEK-2. THERE IS SIGNIFICANT
UNCERTAINTY REGARDING THE SPECIFICS OF TIMING AND LOCATION OF THESE FEATURES
AND RESULTANT IMPACTS. THEREFORE, A BROAD AREA AND EXTENDED TIME PERIOD IS
HIGHLIGHTED WITH A SLIGHT RISK OF HEAVY PRECIPITATION ACROSS THE MID-ATLANTIC
AND GULF COAST STATES FOR THE ENTIRETY OF WEEK-2, WHERE PETS INDICATE AT LEAST
A 20% CHANCE OF 3-DAY LIQUID PRECIPITATION EXCEEDING 0.75 INCHES (1 INCH IN THE
ECENS PET FOR DAYS 10 TO 14). ANTICIPATED FREEZING TEMPERATURES COULD SUPPORT
WINTRY PRECIPITATION ACROSS SOME OF THE HIGHLIGHTED RISK AREAS.
MULTIPLE MODEL ENSEMBLE MEANS DEPICT SURFACE HIGH PRESSURE BUILDING OVER THE
GREAT BASIN WITH AN INVERTED SURFACE TROUGH DEVELOPING ALONG THE COAST OF
CENTRAL AND SOUTHERN CALIFORNIA AT THE BEGINNING OF WEEK-2. THIS PATTERN IS
FAVORABLE FOR SANTA ANA WINDS AND ENHANCED WIND SPEEDS ACROSS SOUTHWESTERN
PORTIONS OF THE CONUS. A MODERATE RISK OF EPISODIC HIGH WINDS IS MAINTAINED FOR
THE SOUTHERN COAST OF CALIFORNIA JAN 23-25. THERE IS INCREASING MODEL
UNCERTAINTY REGARDING THE SYNOPTIC PATTERN ACROSS THE WEST THEREAFTER. IN
GENERAL MULTIPLE MODELS SHOW A LESS FAVORABLE PATTERN FOR SANTA ANA WINDS BY
JAN 26. A BROADER AREA OF SLIGHT RISK IS HIGHLIGHTED FOR PARTS OF ARIZONA AND
THE SOUTHWEST FOR EPISODIC HIGH WINDS THROUGHOUT WEEK-2 PERIOD, WITH THE
ANTICIPATION OF WINDS BY THE MIDDLE OF WEEK-2 HAVING A MORE ONSHORE COMPONENT
AND BE ASSOCIATED WITH THE MID-LEVEL TROUGH RATHER THAN SANTA ANA WINDS.
PREDICTED HIGH WINDS, WARM TEMPERATURES, AND DRY CONDITIONS WOULD EXACERBATE
THE RISK OF WILDFIRES DURING WEEK-2, ESPECIALLY IN AREAS ALREADY EXPERIENCING
ACTIVE WILDFIRES.
MID-LEVEL HIGH PRESSURE IS PREDICTED FOR ALASKA DURING WEEK-2, FAVORING ABOVE
NORMAL TEMPERATURES. NO HAZARDS ARE DESIGNATED FOR THE STATE AT THIS TIME.
FORECASTER: MELISSA OU
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