962
FXUS21 KWNC 171750
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT APRIL 17 2026
SYNOPSIS: THE MID-LEVEL PATTERN IS ANTICIPATED TO WEAKEN THROUGHOUT WEEK-2
RESULTING IN A QUIETER HAZARDS PERIOD COMPARED TO YESTERDAY, WITH MANY OF THEM
WINDING DOWN BY THE ONSET OF THE PERIOD. LEE CYCLOGENESIS MAY LINGER FROM THE
END OF WEEK-1 INTO WEEK-2 OVER THE LEE OF THE ROCKIES, WHICH MAY SUPPORT
ENHANCED WIND SPEEDS. THIS SURFACE LOW PRESSURE AREA MAY TRACK FROM THE CENTRAL
CONTIGUOUS U.S. (CONUS) TO THE GREAT LAKES FROM THE END OF WEEK-1 INTO THE
BEGINNING OF WEEK-2. HEAVY PRECIPITATION REMAINS POSSIBLE SOUTHWARD ALONG THE
TRAILING FRONT ACROSS PARTS OF THE EASTERN SOUTHERN PLAINS, MIDDLE
MISSISSIPPI, TENNESSEE, AND OHIO VALLEYS, SOUTHERN APPALACHIANS, AND SOUTHEAST.
OVER THE UPPER MIDWEST, FLOODING REMAINS POSSIBLE ASSOCIATED WITH ABOVE
FREEZING TEMPERATURES ACCELERATING SPRING SNOWMELT OVER THE NEXT TWO WEEKS.
HAZARDS
SLIGHT RISK OF HEAVY PRECIPITATION FOR PORTIONS OF THE EASTERN SOUTHERN PLAINS,
MIDDLE MISSISSIPPI, TENNESSEE, AND OHIO VALLEYS, SOUTHERN APPALACHIANS, AND
SOUTHEAST, SAT-SUN, APR 25-26.
SLIGHT RISK OF HIGH WINDS FOR PARTS OF THE GREAT PLAINS,SAT, APR 25.
POSSIBLE FLOODING FOR PARTS OF THE GREAT LAKES REGION AND UPPER AND MIDDLE
MISSISSIPPI VALLEY.
DETAILED SUMMARY
FOR MONDAY APRIL 20 - FRIDAY APRIL 24:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR SATURDAY APRIL 25 - FRIDAY MAY 01: DURING WEEK-2, DYNAMICAL MODELS CONTINUE
TO FEATURE A TRANSIENT 500-HPA HEIGHT PATTERN. ANOMALOUS MID-LEVEL TROUGHING
FAVORED ACROSS THE SOUTHWESTERN CONUS AT THE BEGINNING OF WEEK-2 IS ANTICIPATED
TO GRADUALLY WEAKEN OVER THE PERIOD. MEANWHILE A MID-LEVEL SHORT-WAVE TROUGH IS
PREDICTED TO DEVELOP OVER THE NORTH-CENTRAL CONUS AND PROGRESS EASTWARD ACROSS
THE EASTERN CONUS POTENTIALLY LINGERING ACROSS THE REGION TOWARDS THE END OF
WEEK-2. MULTIPLE MODEL ENSEMBLE GUIDANCE CONTINUES TO INDICATE THE DEVELOPMENT
OF AN AMPLIFIED RIDGE CENTERED NEAR THE DAVIS STRAIT CONSISTENT WITH A
TRANSITION TOWARDS A NEGATIVE NORTH ATLANTIC OSCILLATION (-NAO) CIRCULATION.
THIS FEATURE LOOKS TO PEAK AT THE END OF WEEK-1, GRADUALLY WEAKENING THROUGHOUT
WEEK-2. NEGATIVE HEIGHT DEPARTURES ARE ANTICIPATED TO OVERSPREAD MUCH OF THE
EASTERN CONUS FAVORING COOLER TEMPERATURES SHIFTING FROM THE CENTRAL TO THE
NORTHEASTERN CONUS DURING WEEK-2.
THERE CONTINUES TO BE GOOD MODEL AGREEMENT INDICATING INCREASED POTENTIAL OF
ENHANCED PRECIPITATION ACROSS PARTS OF THE INTERIOR EASTERN CONUS. LEE
CYCLOGENESIS IN THE ROCKIES FROM THE END OF WEEK-1 IS ANTICIPATED TO TRANSITION
TO A SURFACE LOW TRACKING NORTHEASTWARD TO THE GREAT LAKES AT THE BEGINNING OF
WEEK-2. THE GREATEST POTENTIAL FOR HEAVIER RAINFALL IS ANTICIPATED SOUTHWARD OF
THE LOW ASSOCIATED WITH THE TRAILING FRONT. A SLIGHT RISK OF HEAVY
PRECIPITATION LINGERING FROM THE END OF WEEK-1 INTO WEEK-2 IS DESIGNATED FOR
PORTIONS OF THE EASTERN SOUTHERN PLAINS, MIDDLE MISSISSIPPI, TENNESSEE, AND
OHIO VALLEYS, SOUTHERN APPALACHIANS, AND SOUTHEAST, APR 25-26. AS ALWAYS,
POSSIBLE THUNDERSTORMS AND ACCUMULATED PRECIPITATION COMBINED WITH WET SOILS
COULD SUPPORT LOCALIZED FLOODING INCLUDING FLASH FLOODING. THE MODERATE RISK IS
NOT INCLUDED IN TODAY’S OUTLOOK DUE TO MUCH OF THE HEAVY PRECIPITATION
ANTICIPATED TO OCCUR BY THE END OF WEEK-1. THE PROBABILISTIC EXTREMES TOOLS
(PETS) INDICATE AT LEAST A 20% CHANCE OF 3-DAY PRECIPITATION (AT THE BEGINNING
OF WEEK-2) EXCEEDING THE 85TH PERCENTILE CLIMATOLOGICALLY AND ONE INCH IN THE
DESIGNATED RISK AREA. FROZEN PRECIPITATION INCLUDING SNOW IS POSSIBLE ACROSS
PARTS OF THE UPPER MIDWEST ON THE NORTHWEST SIDE OF THE SURFACE LOW. HOWEVER,
NO ASSOCIATED SNOW HAZARD IS POSTED DUE TO HIGH UNCERTAINTY REGARDING THE
DETAILS OF THE EVOLUTION OF THIS SYSTEM. THE RISK OF HEAVY SNOW ACROSS THE
ROCKIES IS DISCONTINUED DUE TO THE POTENTIAL SIGNIFICANTLY DECREASING WITH
TIMING OUT OF THE SUPPORTIVE PATTERN.
LINGERING LEE CYCLOGENESIS ACROSS THE GREAT PLAINS FROM THE END OF WEEK-1 MAY
SUPPORT INCREASED LIKELIHOOD OF EPISODIC HIGH WINDS AT THE BEGINNING OF WEEK-2.
THE FORECAST PATTERN FOR WEEK-1 WOULD BE MORE FAVORABLE FOR HIGH WINDS COMPARED
TO WEEK-2. MULTIPLE MODEL TOOLS AND GUIDANCE INCLUDING THE PETS HAVE
SIGNIFICANTLY DECREASED PROBABILITIES OF WIND SPEEDS REACHING HAZARDOUS
CRITERIA. THEREFORE THE MODERATE RISK FOR HIGH WINDS IS DISCONTINUED, WITH A
SLIGHT RISK MAINTAINED FOR PARTS OF THE GREAT PLAINS FOR APR 25. GUSTY WINDS
COULD INCREASE WILDFIRE RISK ESPECIALLY ACROSS THE SOUTHERN PLAINS WHERE SOILS
ARE DRY AND THERE ARE CURRENTLY ACTIVE WILDFIRES.
A FLOODING POSSIBLE HAZARD CONTINUES TO BE POSTED FOR PARTS OF THE GREAT LAKES
REGION AND UPPER AND MIDDLE MISSISSIPPI VALLEY. THESE AREAS HAVE ABOVE-NORMAL
SNOWPACK, WITH ABOVE FREEZING TEMPERATURES ANTICIPATED FOR WEEKS-1 AND 2, IN
ADDITION TO PRECIPITATION ANTICIPATED FOR WEEK-1 WHICH WOULD MAINTAIN FLOOD
CONDITIONS. SEASONAL SPRING MELT LEADING TO SATURATED SOILS AND SUBSEQUENT
CURRENT FLOOD CONDITIONS. HOWEVER, THE THREAT OF FLOODING IS NOT LIMITED TO
THESE AREAS ALONE, AS LINGERING SNOW REMAINS ON THE GROUND OVER PORTIONS OF THE
HIGH PLAINS AS WELL. NO HAZARD IS ISSUED FOR THE RED RIVER OF THE NORTH OR
OTHER WATERCOURSES IN THE REGION, ALTHOUGH RIVER RISES ARE LIKELY AS SNOW MELTS
AND LOCALIZED FLOODING MAY OCCUR.
SURFACE LOW FORMATION IN THE GULF OF ALASKA COMBINED WITH ANOMALOUS COLD
TEMPERATURES AND ABOVE NORMAL PRECIPITATION PREDICTED FOR ALASKA, COULD SUPPORT
ANOMALOUSLY HEAVY LATE SEASON SNOW FOR SOUTHERN MAINLAND ALASKA. NO ASSOCIATED
SNOW HAZARDS ARE POSTED AT THIS TIME WITH THE EXPECTATION FOR TOTALS TO NOT
REACH HAZARDOUS CRITERIA. DESPITE NO ASSOCIATED FLOOD HAZARDS, FLOODING CAN
OCCUR THIS TIME OF YEAR WITH LITTLE OR NO NOTICE DURING RIVER ICE BREAKUP
SEASON. THE COLDER TEMPERATURES IN THE WEEK-2 OUTLOOK INCREASE THE CHANCES OF
DELAYED RIVER BREAKUP IN ALASKA AND INCREASE THE CHANCES OF ICE JAM FLOODING.
CHECK THE ALASKA PACIFIC RIVER FORECAST CENTER
(HTTPS://WWW.WEATHER.GOV/APRFC/BREAKUPMAP) FOR THE LATEST CONDITIONS OR
ADVISORIES.
FORECASTER: MELISSA OU
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