452  
FXUS21 KWNC 032037  
PMDTHR  
US HAZARDS OUTLOOK  
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD  
300 PM EST FEBRUARY 03 2023  
 
SYNOPSIS: MID-LEVEL LOW PRESSURE WITH ONE OR MORE SURFACE STORM SYSTEMS COULD  
BRING BELOW (ABOVE)-NORMAL TEMPERATURES (PRECIPITATION) TO MUCH OF THE WEST,  
WITH HEAVY PRECIPITATION POSSIBLE ACROSS CENTRAL AND SOUTHERN CALIFORNIA, AND  
HEAVY SNOWFALL POSSIBLE IN THE SIERRA NEVADA AND SOME HIGHER ELEVATIONS IN THE  
GREAT BASIN AND FOUR CORNERS REGION. IT SHOULD BE NOTED THAT WHILE SURPLUS  
PRECIPITATION IS ANTICIPATED IN MUCH OF CALIFORNIA, AN EXTREME EVENT LIKE THE  
ONES SEEN EARLIER THIS WINTER APPEARS UNLIKELY AT THIS TIME. MEANWHILE, THE  
STORM SYSTEMS HAVE THE POTENTIAL TO GENERATE HIGH WINDS AT TIMES OVER MUCH OF  
THE CENTRAL AND WESTERN CONTIGUOUS UNITED STATES (CONUS). TO THE EAST, ONE OR  
MORE STORM SYSTEMS EJECTING OUT OF THE SOUTHWEST AND THROUGH THE GREAT LAKES  
REGION COULD DROP HEAVY SNOW ON PORTIONS OF THE UPPER MIDWEST AND HEAVY RAINS  
ACROSS PARTS OF THE SOUTHEAST AND THE MISSISSIPPI, OHIO, AND TENNESSEE VALLEYS.  
 
HAZARDS  
 
SLIGHT RISK OF HEAVY PRECIPITATION FOR PARTS OF THE LOWER MISSISSIPPI, OHIO,  
AND TENNESSEE VALLEYS AND THE SOUTHEAST, MON-FRI, FEB 13-17.  
 
SLIGHT RISK OF HEAVY PRECIPITATION FOR PORTIONS OF CALIFORNIA AND ADJACENT  
NEVADA, SAT-WED, FEB 11-15.  
 
SLIGHT RISK OF HIGH WINDS FOR PARTS WESTERN CONUS AND THE CENTRAL PLAINS,  
SAT-FRI, FEB 11-17.  
 
SLIGHT RISK OF HEAVY SNOW FOR THE HIGHER ELEVATIONS OF THE SIERRA NEVADA IN  
CALIFORNIA, SAT-FRI, FEB 11-17.  
 
SLIGHT RISK OF HEAVY SNOW FOR PARTS OF THE HIGHER ELEVATIONS IN THE FOUR  
CORNERS AND GREAT BASIN, SUN-THU, FEB 12-16.  
 
SLIGHT RISK OF HEAVY SNOW IN THE UPPER MIDWEST, TUE-FRI, FEB 14-17.  
 
DETAILED SUMMARY  
 
FOR MONDAY FEBRUARY 06 - FRIDAY FEBRUARY 10:  
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP  
 
FOR SATURDAY FEBRUARY 11 - FRIDAY FEBRUARY 17: TOOLS ARE IN BETTER AGREEMENT  
THAN YESTERDAY ON THE EVOLUTION OF THE MID-LEVEL PATTERN THROUGH WEEK-2 AS ALL  
ENSEMBLE MEANS SETTLE INTO A PATTERN FEATURING A STRONG ANOMALOUS RIDGE IN THE  
CENTRAL NORTH PACIFIC, A MID-LEVEL TROUGH WITH ITS AXIS IN THE WESTERN CONUS,  
AND ANOTHER 500-HPA RIDGE OVER THE EASTERN CONUS. THE MAIN AREA OF DISAGREEMENT  
IS IN EASTERN CANADA. THE EUROPEAN ENSEMBLE MEAN KEEPS ABOVE-NORMAL 500-HPA  
HEIGHTS IN THIS REGION WHILE THE CANADIAN ENSEMBLE MEAN SHOWS NEAR- TO  
BELOW-NORMAL HEIGHTS IN THE REGION, ESPECIALLY TOWARD THE DAVIS STRAIT. THE  
GEFS IS A COMPROMISE OF THE OTHER TWO ENSEMBLE MEANS. THIS COULD IMPACT  
TEMPERATURES IN THE EASTERN CONUS LATER WEEK-2. IF TEMPERATURES ARE HIGH  
ENOUGH, SNOWMELT AND ICE JAM FLOODING IS POSSIBLE ACROSS PARTS OF NEW ENGLAND,  
BUT CONFIDENCE IS NOT SUFFICIENT TO POST A HAZARD AT THIS TIME. IN ANY CASE,  
THIS PATTERN FAVORS GENERALLY UNSETTLED WEATHER IN MUCH OF THE WEST THROUGH AT  
LEAST THE MIDDLE OF WEEK-2, AND A POTENTIAL STORM TRACK FROM THE SOUTHERN HIGH  
PLAINS THROUGH THE GREAT LAKES COULD TRIGGER HAZARDS FOR WIND, RAIN, AND SNOW  
OVER PARTS OF THE INTERIOR CONUS.  
 
TIMING IS UNCERTAIN, BUT FOR THE MIDDLE AND LATER PART OF WEEK-2, THE MID-LEVEL  
TROUGH HAS THE POTENTIAL TO TRIGGER SEVERAL HAZARDS, PARTICULARLY IN CENTRAL  
AND SOUTHERN SECTIONS OF THE WESTERN CONUS. HEAVY PRECIPITATION IS POSSIBLE  
OVER CENTRAL AND SOUTHERN CALIFORNIA AND ADJACENT NEVADA, ALTHOUGH AN EXTREME  
EVENT LIKE THOSE EXPERIENCED EARLIER THIS WINTER SEEMS UNLIKELY AT THIS TIME.  
WITH CONTINUED SUPPORT IN THE REFORECAST TOOLS, A SLIGHT RISK OF HEAVY  
PRECIPITATION REMAINS POSTED FOR CALIFORNIA FOR FEB 11-15, AS WELL AS A SLIGHT  
RISK OF HEAVY SNOW FOR THE HIGHER ELEVATIONS OF THE STATE FEB 11-17. THE SAME  
FEATURES BRING A SLIGHT RISK OF HEAVY SNOW TO THE HIGHER ELEVATIONS OF THE  
GREAT BASIN AND WESTERN FOUR CORNERS REGION FOR MOST OF WEEK-2 (FEB 12-16), AND  
ANY INDIVIDUAL SURFACE IMPULSES HAS THE POTENTIAL TO BRING HIGH WINDS TO PARTS  
OF THE CENTRAL PLAINS AND WESTERN CONUS. THEREFORE, A SLIGHT RISK OF HIGH WINDS  
REMAINS POSTED FOR THIS PART OF THE COUNTRY FOR THE ENTIRETY OF WEEK-2 TO  
CAPTURE THE UNCERTAINTY IN THE TIMING OF INDIVIDUAL STORM SYSTEMS IN THE  
SOUTHWEST AND THEIR EJECTION NORTHEASTWARD ACROSS THE CENTRAL CONUS DURING THE  
PERIOD.  
 
AFTER EARLY WEEK-2, MOST TOOLS TAKE A HIGH SURFACE PRESSURE CENTER FROM THE  
EASTERN CONUS INTO THE WESTERN NORTH ATLANTIC. THE RESULTING SOUTHERLY SURFACE  
WINDS TO THE WEST OF THE HIGH PRESSURE ARE EXPECTED TO PULL MOIST AIR FROM THE  
GULF OF MEXICO INTO MUCH OF THE SOUTHEASTERN CONUS. MODELS ARE IN BETTER  
AGREEMENT TODAY INDICATING THIS MAY BE ENHANCED BY A SURFACE LOW PRESSURE  
CENTER OR TWO TRACKING FROM SOUTHWESTERN PLAINS THROUGH THE GREAT LAKES REGION  
DURING MID TO LATE WEEK-2. REGARDLESS, THE FLOW OF MOIST, MILD AIR OVER A WEAK  
SURFACE FRONT DRAPED ACROSS THE SOUTHEASTERN CONUS TO THE SOUTH OF THE STORM  
TRACK INCREASES THE CHANCES FOR HEAVY PRECIPITATION FROM THE LOWER MISSISSIPPI  
VALLEY ACROSS THE INTERIOR SOUTHEAST AND SOUTHERN APPALACHIANS. THE GEFS AND  
CANADIAN ENSEMBLE MEANS DROP ABOUT TWICE AS MUCH PRECIPITATION THERE AS THE  
EUROPEAN ENSEMBLE MEAN, ALTHOUGH TOTALS IN THE TWO WETTER MODEL MEANS WERE  
SLIGHTLY LOWER THAN YESTERDAY, IN THE 1.5 TO 2.0 INCH RANGE FROM CENTRAL  
MISSISSIPPI THROUGH NORTHERN GEORGIA AND THE TENNESSEE VALLEY. THE GEFS AND  
EUROPEAN ENSEMBLE REFORECAST TOOLS ARE MORE ROBUST THAN YESTERDAY WITH THE  
CHANCES FOR PRECIPITATION EXCEEDING THE 85TH PERCENTILE OVER THE LOWER  
MISSISSIPPI VALLEY AND SOUTHEAST, BUT STILL APPEAR LOWER THAN INDICATED BY THE  
RAW ENSEMBLE MEAN PRECIPITATION OUTPUTS. BUT THE ANTICIPATED SOUTHERLY FLOW AND  
THE AGREEMENT ON HEAVIER PRECIPITATION IN THE CANADIAN ENSEMBLE MEAN PROMPTS  
THE SLIGHT CHANCE FOR HEAVY PRECIPITATION LATER IN WEEK-2 (FEB 13-17). THIS IS  
CONSISTENT WITH THE SLIGHTLY CYCLONIC MID-LEVEL FLOW EXPECTED FROM THE TROUGH  
CENTERED FARTHER TO THE WEST. CONFIDENCE IS TEMPERED BY THE INCONSISTENCY ON  
THE PRECIPITATION INTENSITY AMONG THE TOOLS, BUT THERE IS SOMEWHAT BETTER  
AGREEMENT THAN YESTERDAY.  
 
THE INCREASED POTENTIAL FOR ONE OR MORE STORMS TRACKING FROM THE SOUTHWEST  
THROUGH THE GREAT LAKES REGION INCREASES THE RISK FOR HEAVY SNOW TO THE NORTH  
OF THE STORM TRACK THROUGH THE UPPER MIDWEST DURING THE MIDDLE AND LATER PART  
OF WEEK-2, AND FOR HIGH WINDS FARTHER WEST IN THE WAKE OF THESE STORMS. THE  
REFORECAST GEFS SNOW WATER EQUIVALENT TOOLS AND THE RAW PRECIPITATION OUTPUT  
FROM MANY OF THE TOOLS INCREASES CONFIDENCE IN THIS DEVELOPMENT, BUT THE  
UNCERTAINTY IN THE STRENGTH AND TIMING OF THE STORMS TRACKING THROUGH THE  
REGION TEMPERS CONFIDENCE SOMEWHAT FOR ANY PARTICULAR LOCATION AND TIME, AND A  
SLIGHT RISK OF HEAVY SNOW IS POSTED FOR FEB 14-17. .  
 
OVER ALASKA, A STRONG STORM SYSTEM WEST OF THE MAINLAND EARLY WEEK-2 COULD  
PRODUCE HEAVY PRECIPITATION AND HIGH WINDS ALONG PARTS OF THE SOUTHERN TIER  
NEAR THE PACIFIC COAST BEFORE THE LOW PRESSURE WEAKENS, REDUCING THE PRESSURE  
GRADIENT AND THEREFORE THE HIGH WINDS AND MOIST PACIFIC INFLOW AS WELL BY THE  
MIDDLE OF WEEK-2.  
 
FORECASTER: RICH TINKER  
 

 
 
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