150
FXUS21 KWNC 051930
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EST NOVEMBER 05 2025
SYNOPSIS: MID-LEVEL LOW PRESSURE IS FORECAST TO PROGRESS FROM THE NORTHEASTERN
PACIFIC INTO THE WEST EARLY IN WEEK-2, INCREASING THE RISK OF MULTIPLE HAZARDS
FROM THE WEST COAST TO INLAND AREAS OF THE WEST. FOLLOWING A BRIEF PERIOD OF
ANOMALOUS COLD ACROSS THE EAST, A QUICK MODERATION IN TEMPERATURES IS LIKELY BY
NOVEMBER 13. ALTHOUGH ABOVE-NORMAL PRECIPITATION IS FAVORED ACROSS MUCH OF
SOUTHERN ALASKA FROM NOVEMBER 13-19, PRECIPITATION AMOUNTS ARE EXPECTED TO
REMAIN BELOW HAZARDOUS THRESHOLDS.
HAZARDS
MODERATE RISK OF HEAVY PRECIPITATION FOR PORTIONS OF CALIFORNIA, THU-FRI, NOV
13-14.
SLIGHT RISK OF HEAVY PRECIPITATION FOR COASTAL PORTIONS OF CENTRAL AND SOUTHERN
CALIFORNIA, THU-SAT, NOV 13-15.
SLIGHT RISK OF HEAVY PRECIPITATION FOR PORTIONS OF THE PACIFIC NORTHWEST AND
NORTHERN TO CENTRAL CALIFORNIA, THU-MON, NOV 13-17.
SLIGHT RISK OF HEAVY PRECIPITATION FOR PARTS OF ARIZONA, FRI-SAT, NOV 14-15.
MODERATE RISK OF HEAVY SNOW FOR THE SIERRA NEVADA MOUNTAINS, THU-FRI, NOV 13-14.
SLIGHT RISK OF HEAVY SNOW FOR PORTIONS OF THE CASCADES, SIERRA NEVADA, AND
KLAMATH MOUNTAINS, THU-MON, NOV 13-17.
SLIGHT RISK OF HEAVY SNOW FOR PORTIONS OF THE NORTHERN AND CENTRAL ROCKIES AND
WASATCH RANGE, FRI-MON, NOV 14-17.
SLIGHT RISK OF HEAVY SNOW FOR THE MOGOLLON RIM OF ARIZONA, FRI-SAT, NOV 14-15.
SLIGHT RISK OF HIGH WINDS ACROSS MUCH OF THE WEST, THU-SAT, NOV 13-15.
DETAILED SUMMARY
FOR SATURDAY NOVEMBER 08 - WEDNESDAY NOVEMBER 12:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR THURSDAY NOVEMBER 13 - WEDNESDAY NOVEMBER 19: THE ECENS, GEFS, AND CMCE ARE
INITIALLY IN GOOD AGREEMENT AND CONSISTENT THAT A VIGOROUS MID-LEVEL TROUGH
APPROACHES OR MOVES INLAND OVER CALIFORNIA BY THE BEGINNING OF WEEK-2, NOVEMBER
13. HOWEVER, THESE ENSEMBLE MEANS DIVERGE EARLY IN WEEK-2 WITH A RANGE OF
OUTCOMES: A SHORTWAVE TROUGH DIGGING SOUTH INTO SOUTHERN CALIFORNIA AND THE
DESERT SOUTHWEST (ECENS), A MORE STATIONARY LONGWAVE TROUGH ALONG THE WEST
COAST (GEFS), AND A PROGRESSIVE LONGWAVE TROUGH SHIFTING FROM THE WESTERN TO
CENTRAL U.S. (CMCE). DESPITE THESE MODEL DIFFERENCES IN HOW THE PATTERN UNFOLDS
LATE NEXT WEEK, THERE IS ENOUGH FORECAST CONFIDENCE AND MODEL SUPPORT,
ESPECIALLY FROM THE ECENS, TO DESIGNATE A MODERATE RISK OF HEAVY PRECIPITATION
FOR SOUTHERN CALIFORNIA ON NOVEMBER 13 AND 14. LOCALLY HEAVY PRECIPITATION
WOULD ELEVATE THE RISK OF URBAN FLASH FLOODING AND MUDSLIDES IN BURN SCAR
AREAS. THE UNCALIBRATED ECENS DEPICTS MORE THAN A 50 PERCENT CHANCE OF MORE
THAN 1 INCH OF PRECIPITATION FOR DAYS 8-10, WHILE IT HAS TRENDED MUCH WETTER ON
DAY 8. THE ECENS PROBABILITIES FOR INTEGRATED VAPOR TRANSPORT VALUES TO EXCEED
250 KG/M/S SHOWS A STRONG WET SIGNAL SHIFTING SOUTH ALONG THE CALIFORNIA COAST
ON DAYS 8 AND 9. BASED ON 24-HOUR PRECIPITATION AMOUNTS FROM THE ENSEMBLE MEANS
AND BOTH THE GEFS AND ECENS PROBABILISTIC EXTREMES TOOLS (PETS) HAVING NEAR OR
MORE THAN A 40 PERCENT CHANCE THAT PRECIPITATION AMOUNTS EXCEED THE 85TH
PERCENTILE, A MODERATE RISK OF HEAVY PRECIPITATION ALSO INCLUDES PORTIONS OF
NORTHERN CALIFORNIA AND THE FOOTHILLS OF THE SIERRA NEVADA MOUNTAINS. THE GEFS
AND ECENS PETS SUPPORT A SLIGHT RISK OF HEAVY PRECIPITATION EXTENDING NORTH TO
THE PACIFIC NORTHWEST AND GOING THROUGH NOVEMBER 17. THE ECENS (> 40 PERCENT
CHANCE OF MORE THAN A FOOT) CONTINUES TO SUPPORT A MODERATE RISK OF HEAVY SNOW
FOR THE SIERRA NEVADA MOUNTAINS ON NOVEMBER 13 AND 14 WITH A SLIGHT RISK OVER A
LARGER SPATIAL AREA INCLUDING THE CASCADES THROUGH THE 17TH.
AS 500-HPA HEIGHTS FALL AND ANOMALOUS MID-LEVEL TROUGHING BECOMES ESTABLISHED
OVER THE WEST, THERE IS LIKELY TO BE A PERIOD OF SNOWFALL ACROSS THE NORTHERN
TO CENTRAL ROCKIES AND WASATCH MOUNTAINS OF UTAH BEGINNING ON NOVEMBER 14
THROUGH AT LEAST THE 17TH. ALTHOUGH MODEL SOLUTIONS DIFFER ON HOW THE 500-HPA
LONGWAVE PATTERN EVOLVES DURING MID-NOVEMBER, THE ECENS AND GEFS AGREE THAT
MOUNTAIN SNOWPACK WILL LIKELY INCREASE PRIOR TO THANKSGIVING. IF THE AMPLIFIED
TROUGH AXIS SHIFTS INLAND, THEN ACCUMULATING SNOW COULD EVEN OCCUR AT LOWER
ELEVATIONS OF THE GREAT BASIN.
A VIGOROUS SHORTWAVE TROUGH MAY SHIFT INLAND TO THE DESERT SOUTHWEST WHICH
WOULD RESULT IN AN INCREASED CHANCE OF HEAVY PRECIPITATION ACROSS ARIZONA EARLY
IN WEEK-2. BASED ON 24-HOUR PRECIPITATION AMOUNTS FROM THE ECENS AND CMCE ALONG
WITH SUPPORT FROM THE ECENS PET, A SLIGHT RISK OF HEAVY PRECIPITATION IS POSTED
FOR PARTS OF ARIZONA ON NOVEMBER 14 AND 15. A MUCH DRIER GEFS PRECLUDES GOING
WITH A MODERATE RISK AT THIS TIME. CONSISTENT WITH THE ENHANCED PRECIPITATION
SIGNAL, A SLIGHT RISK OF HEAVY SNOW IS POSTED FOR THE MOGOLLON RIM OF ARIZONA.
IN ADDITION TO THE HEAVY SNOW AND PRECIPITATION HAZARDS, THE PREDICTED 500-HPA
PATTERN SUPPORTS A SLIGHT RISK OF HIGH WINDS FROM THE PACIFIC COAST OF
CALIFORNIA EAST TO THE CONTINENTAL DIVIDE OF COLORADO AND WYOMING. THE
STRONGEST AND MOST HAZARDOUS WINDS ARE LIKELY TO OCCUR AT THE HIGHER
ELEVATIONS.
DOWNSTREAM OF THE 500-HPA TROUGH AXIS EITHER ALONG OR INLAND OF THE WEST COAST,
THERE IS AN INCREASED CHANCE OF SURFACE LOW DEVELOPMENT ACROSS THE GREAT
PLAINS. THIS SURFACE LOW WOULD THEN MOST LIKELY TRACK NORTHEASTWARD TO THE
UPPER MISSISSIPPI VALLEY OR GREAT LAKES. GIVEN THE ANOMALOUS WARMTH PRECEDING
ANY LOW PRESSURE SYSTEM AND LACK OF ANY STRONG COLD AIR ADVECTION BEHIND IT,
HEAVY SNOWFALL ACROSS THE NORTH-CENTRAL U.S. IS NOT A CONCERN AT THIS TIME.
FORECASTER: BRAD PUGH
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