664
FXUS21 KWNC 311848
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EST JANUARY 31 2024
SYNOPSIS: A WET START TO FEBRUARY IS FORECAST ACROSS CALIFORNIA AND THE
SOUTHWEST. HOWEVER, DURING THE SECOND WEEK OF THE MONTH, A DRYING TREND IS
EXPECTED THROUGHOUT THE WEST AS MID-LEVEL HIGH PRESSURE BUILDS OVER THE PACIFIC
NORTHWEST. ABOVE-NORMAL PRECIPITATION IS FAVORED ACROSS THE CENTRAL U.S. FROM
FEBRUARY 8-14, BUT ANY HEAVY SNOW RISK IS LIKELY TO BE LIMITED TO THE NORTHERN
GREAT PLAINS AND UPPER MISSISSIPPI VALLEY. FOLLOWING A PERIOD WITH MUCH
BELOW-NORMAL TEMPERATURES ACROSS ALASKA AT THE END OF JANUARY, A MAJOR WARMING
TREND IS FORECAST DURING THE NEXT TWO WEEKS.
HAZARDS
MODERATE RISK OF HEAVY PRECIPITATION FOR PARTS OF SOUTHERN CALIFORNIA AND
ARIZONA, THU-FRI, FEB 8-9.
MODERATE RISK OF HEAVY SNOW FOR PARTS OF THE SOUTHWEST, GREAT BASIN, AND
CENTRAL ROCKIES, THU-FRI, FEB 8-9.
SLIGHT RISK OF HEAVY PRECIPITATION FOR MUCH OF CALIFORNIA AND THE SOUTHWEST,
THU-FRI, FEB 8-9.
SLIGHT RISK OF HEAVY SNOW FOR THE HIGHER ELEVATIONS OF CALIFORNIA, THE GREAT
BASIN, SOUTHWEST, AND ROCKIES, THU-FRI, FEB 8-9.
SLIGHT RISK OF HEAVY SNOW FOR THE NORTHERN TO CENTRAL GREAT PLAINS AND UPPER
MISSISSIPPI VALLEY, THU-SAT, FEB 8-10.
MODERATE RISK OF HIGH WINDS FOR SOUTHERN CALIFORNIA, THE SOUTHWEST, AND CENTRAL
TO SOUTHERN HIGH PLAINS, THU, FEB 8.
SLIGHT RISK OF HIGH WINDS FOR SOUTHERN CALIFORNIA, THE SOUTHWEST, AND CENTRAL
TO SOUTHERN GREAT PLAINS, THU-SAT, FEB 8-10.
SLIGHT RISK OF HEAVY PRECIPITATION FOR SOUTHEASTERN OKLAHOMA, EASTERN TEXAS,
MIDDLE TO LOWER MISSISSIPPI VALLEY, OHIO AND TENNESSEE VALLEYS, AND PARTS OF
THE SOUTHEAST, FRI-MON, FEB 9-12.
SLIGHT RISK OF HEAVY PRECIPITATION FOR KODIAK ISLAND, THE KENAI PENINSULA, AND
SOUTHEASTERN ALASKA, SUN-WED, FEB 11-14.
FLOODING POSSIBLE FOR EASTERN TEXAS AND THE LOWER MISSISSIPPI VALLEY ALONG WITH
PARTS OF THE SOUTHWEST AND CALIFORNIA.
DETAILED SUMMARY
FOR SATURDAY FEBRUARY 03 - WEDNESDAY FEBRUARY 07:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR THURSDAY FEBRUARY 08 - WEDNESDAY FEBRUARY 14: THE 0Z GEFS, ECMWF, AND
CANADIAN ENSEMBLE MEANS DEPICT A VIGOROUS 500-HPA SHORTWAVE TROUGH TRACKING
EASTWARD ACROSS SOUTHERN CALIFORNIA AND THE SOUTHWEST NEXT WEEK. BASED ON A
CONSENSUS BETWEEN THE GEFS AND ECMWF PROBABILISTIC EXTREMES TOOLS (PETS) ALONG
WITH UNCALIBRATED 24-HOUR AMOUNTS FROM THE GEFS, ECMWF, AND CANADIAN MODELS, A
MODERATE RISK OF HEAVY PRECIPITATION (LIKELY MORE THAN 1 INCH, LIQUID
EQUIVALENT) IS POSTED FOR PARTS OF SOUTHERN CALIFORNIA AND ARIZONA. A BROADER
SLIGHT RISK OF HEAVY PRECIPITATION IS SUPPORTED BY THE PETS. BEYOND FEBRUARY 9,
THE SIGNAL FOR HEAVY PRECIPITATION DIMINISHES AS 500-HPA HEIGHTS RISE ALONG THE
WEST COAST AND SURFACE HIGH PRESSURE BECOMES ESTABLISHED ACROSS THE GREAT
BASIN. THE POTENT MID-LEVEL TROUGH FAVORED EARLY IN WEEK-2 SUPPORTS A MODERATE
RISK OF HEAVY SNOW (FEBRUARY 8 AND 9) AT THE HIGHER ELEVATIONS OF ARIZONA,
COLORADO, AND UTAH. A SLIGHT RISK OF HEAVY SNOW, FOR THOSE SAME DATES, EXTENDS
NORTHWARD TO INCLUDE MORE OF THE GREAT BASIN AND CENTRAL ROCKIES AS THE
MID-LEVEL TROUGH BEGINS TO SHIFT INLAND. BASED ON PATTERN RECOGNITION WITH THE
MID-LEVEL TROUGH CROSSING THE FOUR CORNERS REGION AND LEESIDE SURFACE
CYCLOGENESIS, A MODERATE RISK OF HIGH WINDS (FEBRUARY 8) IS POSTED FOR SOUTHERN
CALIFORNIA, THE SOUTHWEST, AND CENTRAL TO SOUTHERN HIGH PLAINS. A SLIGHT RISK
COVERING A BROADER AREA OF THE WEST AND CENTRAL TO SOUTHERN GREAT PLAINS IS
VALID THROUGH FEBRUARY 10.
AN AMPLIFIED 500-HPA TROUGH OVER THE WEST IS LIKELY TO RESULT IN SURFACE LOW
DEVELOPMENT ACROSS SOUTHEASTERN COLORADO BY FEBRUARY 8 OR 9. A SWATH OF SNOW,
POTENTIALLY HEAVY, MAY ACCOMPANY A LOW PRESSURE SYSTEM TRACKING NORTHEASTWARD
ACROSS THE NORTH-CENTRAL GREAT PLAINS AND UPPER MISSISSIPPI VALLEY. A
MITIGATING FACTOR ON HEAVY SNOWFALL WILL BE THE ANTECEDENT WARM AIRMASS OVER
THE CENTRAL U.S. DURING EARLY FEBRUARY. LATER IN WEEK-2, THERE COULD BE ANOTHER
LOW PRESSURE SYSTEM AFFECTING THE MIDWEST BUT ITS TRACK AND ASSOCIATED
PRECIPITATION AMOUNTS/TYPE ARE HIGHLY UNCERTAIN.
DOWNSTREAM OF THE 500-HPA TROUGH OVER THE SOUTHWEST, THERE IS AN INCREASED
CHANCE OF HEAVY PRECIPITATION ACROSS THE MIDDLE TO LOWER MISSISSIPPI VALLEY,
OHIO AND TENNESSEE VALLEYS, AND PARTS OF THE SOUTHEAST. BASED ON UNCALIBRATED
24-HOUR AMOUNTS FROM THE GEFS, ECMWF, AND CANADIAN MODELS ALONG WITH THE GEFS
AND ECMWF PETS, A SLIGHT RISK OF HEAVY PRECIPITATION IS POSTED FOR THOSE AREAS
FROM FEBRUARY 9-12.
MINOR TO MODERATE RIVER FLOODING IS EXPECTED TO PERSIST THROUGH AT LEAST
MID-FEBRUARY ACROSS THE LOWER MISSISSIPPI VALLEY DUE TO: ADDITIONAL RAINFALL (1
TO 3 INCHES) DURING THE NEXT 7 DAYS AND FAVORED WETNESS DURING THE FOLLOWING
WEEK. A FLOODING HAZARD IS MAINTAINED ACROSS PARTS OF CALIFORNIA AND ARIZONA
SINCE THERE REMAINS FLOODING CONCERNS RELATED TO HEAVY PRECIPITATION ONGOING
AND THROUGH THE MIDDLE PART OF NEXT WEEK.
THE GEFS, ECMWF, AND CANADIAN ENSEMBLE MEANS REMAIN CONSISTENT AND IN GOOD
AGREEMENT WITH AN AMPLIFIED 500-HPA TROUGH AND MEAN SURFACE LOW OVER THE
ALEUTIANS. ENHANCED ONSHORE IS LIKELY TO AFFECT SOUTHERN ALASKA AND BASED ON
THE GEFS AND ECMWF PETS, A SLIGHT RISK OF HEAVY PRECIPITATION IS POSTED FOR
KODIAK ISLAND, THE KENAI PENINSULA, AND SOUTHEASTERN ALASKA FROM FEBRUARY
11-14.
FORECASTER: BRAD PUGH
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