530
FXUS21 KWNC 221806
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT OCTOBER 22 2024
SYNOPSIS: MID-LEVEL LOW (HIGH) PRESSURE OVER THE WESTERN (EASTERN) HALF OF THE
CONTIGUOUS U.S. (CONUS) IS PREDICTED FOR THE WEEK-2 PERIOD. THIS PATTERN FAVORS
A SLIGHT RISK OF HEAVY PRECIPITATION FOR PARTS OF THE MIDDLE AND LOWER
MISSISSIPPI VALLEY, AND CENTRAL AND SOUTHERN PLAINS, WITH THE POTENTIAL FOR
HIGH WINDS ACROSS THE CENTRAL CONUS AT THE BEGINNING OF THE PERIOD. AMPLIFIED
MID-LEVEL LOW PRESSURE OVER THE ALASKA MAINLAND IS ANTICIPATED TO BRING
ANOMALOUSLY COOL TEMPERATURES TO MUCH OF ALASKA. THIS PATTERN MAY ALSO SUPPORT
SURFACE LOWS OVER THE BERING SEA AND GULF OF ALASKA THAT COULD LEAD TO HIGH
WINDS TO COASTAL PORTIONS OF SOUTHERN ALASKA INCLUDING SOUTHWESTERN ALASKA AND
THE ALEUTIANS.
HAZARDS
SLIGHT RISK OF HEAVY PRECIPITATION FOR PARTS OF THE MIDDLE AND LOWER
MISSISSIPPI VALLEY AND CENTRAL AND SOUTHERN PLAINS, WED-FRI, OCT 30-NOV 1.
SLIGHT RISK OF HIGH WINDS ACROSS PORTIONS OF THE CENTRAL CONUS, WED-FRI, OCT
30-NOV 1.
SLIGHT RISK OF HIGH WINDS FOR COASTAL SOUTHERN ALASKA INCLUDING SOUTHWESTERN
ALASKA, AND THE ALEUTIANS, WED-FRI, OCT 30-NOV 1.
DETAILED SUMMARY
FOR FRIDAY OCTOBER 25 - TUESDAY OCTOBER 29:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR WEDNESDAY OCTOBER 30 - TUESDAY NOVEMBER 05: THERE IS GOOD AGREEMENT AMONG
MULTIPLE MODEL ENSEMBLE MEANS INDICATING MID-LEVEL TROUGHING (RIDGING) OVER THE
WESTERN (EASTERN) HALF OF THE CONUS DURING WEEK-2, GRADUALLY DECREASING IN
AMPLITUDE BY DAY 11 (NOV 2). THIS PATTERN IS CONDUCIVE TO LEE CYCLOGENESIS AND
FRONTAL ACTIVITY OVER THE CENTRAL CONUS WHICH COULD SUPPORT ENHANCED WIND
SPEEDS AND PRECIPITATION AT THE BEGINNING OF WEEK-2. A SLIGHT RISK OF HEAVY
PRECIPITATION IS HIGHLIGHTED ACROSS PARTS OF THE MIDDLE AND LOWER MISSISSIPPI
VALLEY, CENTRAL AND SOUTHERN PLAINS, OCT 30-NOV 1, ASSOCIATED WITH THE
INCREASED POTENTIAL FOR THUNDERSTORMS WHICH MAY PRODUCE LOCALIZED HEAVY
PRECIPITATION. THE RISK AREA HIGHLIGHTED IS PRIMARILY BASED ON THE ECENS WHICH
IS MORE SUPPORTIVE OF THIS HEAVY PRECIPITATION SIGNAL THAN THE GEFS, WITH THE
ASSOCIATED PROBABILISTIC EXTREMES TOOL (PET) INDICATING AT LEAST A 30% CHANCE
OF 3-DAY RAINFALL TOTALS EXCEEDING THE 85TH PERCENTILE CLIMATOLOGICALLY. TOTALS
MAY EXCEED ONE INCH IN THE DESIGNATED TIME PERIOD. THE GEFS’ SIGNAL IS MUCH
WEAKER, INDICATING ONLY AT LEAST A 20% CHANCE OF EXCEEDING THE 85TH PERCENTILE,
WITH ONE INCH TOTALS LIMITED TO THE SOUTHERN PLAINS.
THE AFOREMENTIONED FRONTAL SYSTEM MAY ALSO SUPPORT ENHANCED WIND SPEEDS.
ADDITIONALLY, SOME MODELS INDICATE A STRONGER SURFACE LOW TRACKING ACROSS THE
NORTHERN PLAINS COMPARED TO YESTERDAY, WHICH WOULD BE MORE SUPPORTIVE OF HIGH
WINDS ACROSS THE CENTRAL CONUS. THEREFORE, THE AREA OF A SLIGHT RISK OF HIGH
WINDS IS SHIFTED SLIGHTLY NORTHWARD TO INCLUDE MORE OF THE NORTH-CENTRAL CONUS
COMPARED TO YESTERDAY’S OUTLOOK, FOR OCT 30 TO NOV 1. THE GEFS, ECENS, AND
CANADIAN PETS ARE IN GOOD AGREEMENT INDICATING AT LEAST A 20% CHANCE OF WIND
SPEEDS EXCEEDING THE 85TH PERCENTILE AND 20 MPH ACROSS THE HIGHLIGHTED RISK
AREA.
MULTIPLE ENSEMBLE MEANS INDICATE STRONGER MID-LEVEL TROUGHING OVER ALASKA
COMPARED TO YESTERDAY, TRANSLATING TO INCREASING SIGNALS FOR ANOMALOUS COLD
OVER PARTS OF THE STATE. THE PETS ARE INDICATING AT LEAST A 20% CHANCE OF
MINIMUM TEMPERATURES FALLING TO THE LOWEST 15TH PERCENTILE AND -20 DEG F, WHICH
ALTHOUGH ANOMALOUS, IS NOT CONSIDERED HAZARDOUS AT THIS TIME OF YEAR. MID-LEVEL
TROUGHING MAY ALSO SUPPORT SURFACE LOWS OVER THE BERING SEA AND THE GULF OF
ALASKA, SUPPORTING A SLIGHT RISK OF HIGH WINDS FOR COASTAL PORTIONS OF SOUTHERN
ALASKA INCLUDING SOUTHWESTERN ALASKA AND THE ALEUTIANS, OCT 30-NOV 1. PETS SHOW
AT LEAST A 20% CHANCE OF WIND SPEEDS EXCEEDING THE 85TH PERCENTILE AND 40 MPH.
HIGH WINDS AND WAVE ACTION COULD ENHANCE THE LIKELIHOOD FOR EROSION ACROSS
SOUTHWESTERN COASTAL ALASKA.
FORECASTER: MELISSA OU
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