781
FXUS21 KWNC 171847
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EST JANUARY 17 2025
SYNOPSIS: MID-LEVEL LOW PRESSURE ACROSS THE EASTERN CONTIGUOUS U.S. (CONUS) IS
PREDICTED TO CONTINUE LINGERING INCREASED RISK OF HAZARDOUS COLD TEMPERATURES
FROM THE END OF WEEK-1 INTO THE BEGINNING OF WEEK-2 TO PARTS OF THE
SOUTH-CENTRAL AND SOUTHEASTERN 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 CONTINUE OVER THE GREAT BASIN WITH
SURFACE LOW PRESSURE DEVELOPING ALONG CENTRAL AND SOUTHERN COASTAL CALIFORNIA
FROM WEEK-1 INTO THE START OF WEEK-2. THIS PATTERN MAY CONTINUE PERIODS OF HIGH
WINDS WITH AN OFFSHORE COMPONENT ACROSS SOUTHERN COASTAL CALIFORNIA AT THE
ONSET OF WEEK-2, WITH INCREASING UNCERTAINTY FOR THE DURATION OF THIS FLOW
THEREAFTER. INCREASED RISK FOR HIGH WINDS ARE EXPECTED FOR THE REST OF WEEK-2
THEREAFTER ACROSS COASTAL PORTIONS OF CALIFORNIA AND PARTS OF THE SOUTHWEST,
ASSOCIATED WITH MID-LEVEL LOW PRESSURE DEVELOPING OVER THE WEST. A SERIES OF
PREDICTED SURFACE LOWS AND ASSOCIATED FRONTS ACROSS THE EASTERN HALF OF THE
CONUS MAY LEAD TO PERIODS OF HEAVY PRECIPITATION ACROSS PARTS OF THE GULF COAST
STATES AND THE MID-ATLANTIC. 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 HIGH WINDS ACROSS COASTAL PORTIONS OF SOUTHERN CALIFORNIA,
SAT, JAN 25.
SLIGHT RISK OF PERIODS OF HIGH WINDS FOR PARTS OF THE SOUTHWEST AND SOUTHERN
CALIFORNIA, SAT-WED, JAN 25-29.
SLIGHT RISK OF PERIODS OF HIGH WINDS FOR COASTAL PORTIONS OF NORTH AND CENTRAL
CALIFORNIA, SAT-MON, JAN 25-27.
SLIGHT RISK OF MUCH BELOW NORMAL TEMPERATURES ACROSS PORTIONS OF THE
SOUTH-CENTRAL AND SOUTHEASTERN CONUS, SAT, JAN 25.
SLIGHT RISK OF EPISODIC HEAVY PRECIPITATION FOR PORTIONS OF THE MID-ATLANTIC
AND GULF COAST STATES, SAT-FRI, JAN 25-31.
DETAILED SUMMARY
FOR MONDAY JANUARY 20 - FRIDAY JANUARY 24:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR SATURDAY JANUARY 25 - FRIDAY JANUARY 31: MULTIPLE MODEL ENSEMBLE MEANS
INDICATE MID-LEVEL LOW PRESSURE LINGERING BRIEFLY OVER THE EASTERN HALF OF THE
CONUS FROM THE END OF WEEK-1 INTO THE ONSET OF WEEK-2. A SLIGHT RISK OF MUCH
BELOW NORMAL TEMPERATURES IS MAINTAINED FOR PORTIONS OF THE SOUTH-CENTRAL AND
SOUTHEASTERN CONUS, JAN 25, WITH TEMPERATURES ANTICIPATED TO MODERATE
THEREAFTER ACROSS THE EAST. THE PROBABILISTIC EXTREMES TOOLS (PETS) INDICATE AT
LEAST A 20% CHANCE OF TEMPERATURES FALLING TO THE LOWEST 15TH PERCENTILE
CLIMATOLOGICALLY. SUB-FREEZING TEMPERATURES ARE PREDICTED ACROSS THE REGION,
WITH LOWER WIND CHILL VALUES POSSIBLE.
UPSTREAM, MID-LEVEL LOW PRESSURE EXTENDING FROM THE NORTH-CENTRAL CONUS TO
SOUTHWEST IS PREDICTED TO SHIFT EASTWARD OVER TIME, ALTHOUGH THERE IS
SIGNIFICANT MODEL VARIANCE REGARDING THE AMPLITUDE OF THIS TROUGH AND
EVOLUTION. THE ECENS AND CMCE CONTINUE TO FAVOR A MORE AMPLIFIED TROUGH THAN
THE GEFS, TRANSLATING TO A MORE ANOMALOUS COLD PATTERN. THE GEFS AND ECENS PETS
INDICATE AT LEAST A 20% CHANCE OF MINIMUM TEMPERATURES FALLING TO THE LOWEST
15TH PERCENTILE AND -10 DEG F ACROSS PORTIONS OF THE NORTH-CENTRAL CONUS. DUE
TO THESE VALUES NOT REACHING COLD HAZARD CRITERIA AND THE GEFS NOT REACHING
THESE THRESHOLDS, AN ASSOCIATED MUCH BELOW NORMAL TEMPERATURE IS NOT DESIGNATED
FOR THE NORTH-CENTRAL CONUS AT THIS TIME.
SIGNIFICANT UNCERTAINTY IN THE TROUGH EVOLUTION TRANSLATES TO UNCERTAINTY
REGARDING THE SPECIFICS OF TIMING AND LOCATION OF SURFACE LOWS AND ASSOCIATED
FRONTS OVER THE EASTERN HALF OF THE CONUS DURING WEEK-2. THEREFORE, A BROAD
AREA AND EXTENDED TIME PERIOD REMAINS HIGHLIGHTED WITH A SLIGHT RISK (20-40%
CHANCE) 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 1 INCH. WITH SIGNALS FOR MUCH BELOW NORMAL
TEMPERATURES DECREASING WITH TIME DURING WEEK-2, THERE IS MORE UNCERTAINTY
REGARDING THE POTENTIAL FOR WINTRY PRECIPITATION ACROSS THE DEEP SOUTH.
SOME MODEL ENSEMBLE MEANS DEPICT THE POTENTIAL FOR SURFACE HIGH PRESSURE
LINGERING OVER THE GREAT BASIN WITH AN INVERTED SURFACE TROUGH ALONG THE COAST
OF CENTRAL AND SOUTHERN CALIFORNIA FROM THE END OF WEEK-1 INTO THE START OF
WEEK-2. THIS PATTERN MAY REMAIN FAVORABLE FOR SANTA ANA WINDS AND ENHANCED WIND
SPEEDS ACROSS SOUTHWESTERN PORTIONS OF THE CONUS AT THE START OF WEEK-2. A
MODERATE RISK OF HIGH WINDS REMAINS DESIGNATED FOR THE SOUTHERN COAST OF
CALIFORNIA JAN 25, ALTHOUGH THERE IS INCREASING UNCERTAINTY IN THE MODELS FOR
THIS DAY REGARDING THE DEGREE OF OFFSHORE COMPONENT AND PRECISELY WHEN A SHIFT
TO MORE ONSHORE FLOW OCCURS. A BROADER AREA OF SLIGHT RISK IS HIGHLIGHTED FOR
PARTS OF CALIFORNIA AND THE SOUTHWEST FOR EPISODIC HIGH WINDS JAN 25-29, WITH
THE ANTICIPATION OF WINDS HAVING A MORE ONSHORE COMPONENT ASSOCIATED WITH THE
MID-LEVEL TROUGH AFTER DAY 8 (JAN 26 ONWARD). PREDICTED HIGH WINDS, WARM
TEMPERATURES, AND DRY CONDITIONS WOULD EXACERBATE THE RISK OF WILDFIRES DURING
WEEK-2, ESPECIALLY IN AREAS ALREADY EXPERIENCING ACTIVE WILDFIRES. A SLIGHT
RISK OF EPISODIC HIGH WINDS IS HIGHLIGHTED FOR JAN 25-27 ALONG COASTAL PORTIONS
OF CENTRAL TO NORTHERN CALIFORNIA WHERE PETS INDICATE AT LEAST A 20% CHANCE OF
WIND SPEEDS EXCEEDING THE 85TH PERCENTILE AND 25 MPH.
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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