150
FXUS21 KWNC 151918
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EST NOVEMBER 15 2025
SYNOPSIS: MID-LEVEL HIGH PRESSURE OVER ALASKA AND MID-LEVEL LOW PRESSURE OVER
THE WESTERN CONTIGUOUS U.S. (CONUS) ARE BOTH PREDICTED TO STRENGTHEN EARLY IN
THE WEEK-2 FORECAST PERIOD. MID-LEVEL HIGH PRESSURE IS ALSO FORECAST ACROSS THE
EASTERN CONUS. THIS MID-LEVEL PATTERN IS EXPECTED TO DRIVE VARIOUS HAZARDS
ACROSS THE LOWER 48 STATES DURING THE WEEK-2 FORECAST, INCLUDING AN INFLOW OF
ARCTIC AIR, HEAVY MOUNTAIN SNOW, AND GUSTY WINDS FOR PORTIONS OF THE WEST.
PARTS OF THE CENTRAL AND EASTERN CONUS MAY BE IMPACTED BY HEAVY PRECIPITATION,
HEAVY SNOW, GUSTY WINDS, AND FLOODING.
HAZARDS
SLIGHT RISK OF HEAVY PRECIPITATION FOR EASTERN PORTIONS OF THE SOUTHERN PLAINS,
MIDDLE AND LOWER MISSISSIPPI VALLEY, SOUTHERN OHIO AND TENNESSEE VALLEYS, AND
ADJACENT PARTS OF THE SOUTHEAST, SUN-TUE, NOV 23-25, AND FRI-SAT, NOV 28-29.
SLIGHT RISK OF HEAVY SNOW FOR MUCH OF THE MOUNTAINOUS WEST, SUN-SAT, NOV 23-29.
SLIGHT RISK OF HEAVY SNOW OVER MUCH OF THE NORTHERN AND CENTRAL PLAINS AND
UPPER MISSISSIPPI VALLEY, WED-SAT, NOV 26-29.
SLIGHT RISK OF MUCH BELOW-NORMAL TEMPERATURES ACROSS MUCH OF THE WESTERN HALF
OF THE CONUS, TUE-SAT, NOV 25-29.
SLIGHT RISK OF HIGH WINDS OVER MOST OF THE CONUS, SUN-SAT, NOV 23-29.
FLOODING POSSIBLE IN THE GENERAL VICINITY OF THE ARKLATEX.
DETAILED SUMMARY
FOR TUESDAY NOVEMBER 18 - SATURDAY NOVEMBER 22:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR SUNDAY NOVEMBER 23 - SATURDAY NOVEMBER 29: EARLY IN THE WEEK-2 PERIOD, AN
AMPLIFYING MID-LEVEL RIDGE OVER ALASKA IS EXPECTED TO CONTRIBUTE TO THE
DEEPENING OF A MID-LEVEL TROUGH DOWNSTREAM OVER THE WESTERN CONUS. THIS
SCENARIO IS PREDICTED TO BRING ANOMALOUSLY WARM AIR TO ALASKA AND ANOMALOUSLY
COLD ARCTIC AIR TO THE WESTERN LOWER 48 STATES. SIGNIFICANTLY ANOMALOUSLY WARM
TEMPERATURES PREDICTED IN SOUTHWESTERN ALASKA FAVORS PRECIPITATION IN THE FORM
OF RAIN RATHER THAN SNOW FOR MANY AREAS, WHICH COULD LEAD TO A NUMBER OF
HAZARDOUS IMPACTS INCLUDING COASTAL EROSION, FLOODING, AND A DECREASE IN THE
STABILITY OF ICE ON RIVERS AND LAKES. FOR THE WESTERN CONUS, TEMPERATURES ARE
EXPECTED TO FALL BELOW 20 DEG F IN MANY AREAS, AND A HARD FREEZE (28 DEG F) IS
A SIGNIFICANT CONCERN FOR NEAR-COASTAL AREAS OF THE PACIFIC NORTHWEST,
INCLUDING SEATTLE AND PORTLAND. THESE MINIMUM TEMPERATURES COULD BRING AN END
TO THE GROWING SEASON ACROSS OREGON'S WILLAMETTE VALLEY, AND ARE SUPPORTED BY
0Z RUNS OF THE ECENS AND GEFS. A SLIGHT RISK OF MUCH BELOW-NORMAL TEMPERATURES
IS FAVORED ACROSS MUCH OF THE WESTERN HALF OF THE CONUS, NOV 25-29.
AS THE MID-LEVEL TROUGH DEEPENS ACROSS THE WEST AND PROGRESSES SLOWLY EASTWARD,
A SLIGHT RISK FOR HEAVY SNOW IS POSTED FOR MUCH OF THE MOUNTAINOUS WEST, NOV
23-29. THIS IS CONSISTENT WITH RAW (UNCALIBRATED) SNOWFALL GUIDANCE FROM THE
ECENS AND (TO A LESSER EXTENT) THE GEFS, WITH PREDICTED SNOWFALL TOTALS IN
EXCESS OF 6 INCHES, AND LOCALLY A FOOT OR MORE IN THE HIGHEST ELEVATIONS. BROAD
CYCLONIC CURVATURE AND COLD AIR ALOFT IS EXPECTED TO MAINTAIN THE NECESSARY
INSTABILITY TO GENERATE SIGNIFICANT SNOWFALL ACROSS THE WEST, SUBSTANTIALLY
BOOSTING MOUNTAIN SNOWPACKS IN THE PROCESS. IN ADDITION TO THE PREDICTED ARCTIC
AIR AND HEAVY SNOW HAZARDS ACROSS THE WEST, INCREASED CHANCES FOR GUSTY WINDS
OF 20-30 MPH OR MORE ARE INDICATED BY THE ECENS AND GEFS PROBABILISTIC EXTREMES
TOOLS (PETS) WIND GUIDANCE. THIS IS FURTHER SUPPORTED BY FORECAST 10-METER WIND
SPEEDS FROM THE 0Z ECENS ENSEMBLE MEAN, AND THE EXPECTATION OF TIGHTER SURFACE
PRESSURE GRADIENTS. THESE TIGHTER PRESSURE GRADIENTS ARE EXPECTED TO BE NEAR
THE SOUTHERN EDGES OF ADVANCING ARCTIC AIR MASSES SURGING SOUTHWARD ACROSS THE
WEST. ACCORDINGLY, A SLIGHT RISK OF EPISODIC HIGH WINDS IS FAVORED ACROSS MOST
OF THE WESTERN CONUS FOR THE DURATION OF WEEK-2.
OVER THE CENTRAL CONUS, LEESIDE CYCLOGENESIS IS PREDICTED BY THE GEFS AND ECENS
MODELS, WITH SEVERAL SURFACE LOW PRESSURE CENTERS TRACKING FROM THE VICINITY OF
EASTERN COLORADO TOWARDS THE UPPER GREAT LAKES REGION, WHICH IS A VERY COMMON
STORM TRACK FOR LATE NOVEMBER. A SLIGHT RISK OF HEAVY SNOW (>85TH HISTORICAL
PERCENTILE AND 4-6+ INCHES) IS POSTED FOR THE NORTHERN AND WESTERN FLANKS OF
ONE OF THESE DISTURBANCES AS IT TRACKS TOWARDS THE UPPER GREAT LAKES REGION
DURING THE SECOND HALF OF THE FORECAST PERIOD. THIS MAY CAUSE SOME TRAVEL
DISRUPTIONS FOR THE THANKSGIVING HOLIDAY. THE AREA EXPECTED TO BE MOST AFFECTED
BY THIS STORM SYSTEM INCLUDES THE NORTHERN AND CENTRAL GREAT PLAINS AND
PORTIONS OF THE UPPER MISSISSIPPI VALLEY. SURFACE HIGH PRESSURE NEAR OR OFF THE
SOUTHEAST COAST FAVORS AN INCREASE IN MOIST SOUTHERLY RETURN FLOW AND A SLIGHT
RISK OF HEAVY PRECIPITATION ACROSS SOUTH-CENTRAL AND SOUTHEASTERN PORTIONS OF
THE CONUS AS FAR NORTH AS THE OHIO VALLEY, ON NOV 23-25. A SECOND ROUND OF
HEAVY PRECIPITATION IS INDICATED BY MULTIPLE NUMERICAL MODELS ON NOV 28-29, IN
RESPONSE TO ANOTHER PASSING DISTURBANCE. PRECIPITATION AMOUNTS OF AT LEAST
1-INCH ARE FORECAST (3-DAY PERIOD), AND AS MUCH AS 4-7 INCHES OF PRECIPITATION
ARE PREDICTED FOR MUCH OF THIS SAME AREA DURING THE PRECEDING WEEK-1 PERIOD. AS
A RESULT, AN AREA OF POSSIBLE FLOODING IS DEEMED MOST LIKELY IN THE ARKLATEX
REGION.
FOR MUCH OF THE CONUS EAST OF THE ROCKIES, DYNAMICAL MODELS INDICATE SEVERAL
LOW PRESSURE SYSTEMS ARE ANTICIPATED TO MOVE THROUGH THESE REGIONS DURING THE
WEEK-2 PERIOD, ACCOMPANIED BY GUSTY NORTHWESTERLY WINDS OF 20-30 MPH. MULTIPLE
STORM SYSTEMS AFFECTING THE CENTRAL AND EASTERN CONUS AT DIFFERENT TIMES DURING
WEEK-2 NECESSITATES THE DESIGNATION OF A VERY BROAD AREA OF EPISODIC HIGH
WINDS. IN THE GREAT LAKES REGION, LAKE-ENHANCED PRECIPITATION CAN BE EXPECTED
IN THE WAKE OF INDIVIDUAL SYNOPTIC-SCALE DISTURBANCES. HOWEVER, IF THE ARCTIC
AIR PREDICTED TO IMPACT THE WESTERN CONUS DURING WEEK-2 MOVES ACROSS THE
EASTERN CONUS AFTER THE WEEK-2 PERIOD, THE COLDER AIR STREAMING OVER THE
RELATIVELY WARM WATERS OF THE GREAT LAKES WILL MOST LIKELY RESULT IN
SIGNIFICANT LAKE-EFFECT PRECIPITATION FOR THE TYPICAL CLIMATOLOGICAL SNOWBELT
AREAS DOWNWIND OF THE LAKES.
FORECASTER: ANTHONY ARTUSA
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