768
FXUS21 KWNC 191736
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT APRIL 19 2024
SYNOPSIS: ON APRIL 27 AND 28, A SURFACE LOW AND TRAILING COLD FRONT ARE
FORECAST TO TRACK EASTWARD OVER THE CENTRAL U.S. THUNDERSTORMS AND HEAVY
RAINFALL ARE MOST LIKELY ACROSS THE SOUTHERN TO CENTRAL GREAT PLAINS AND LOWER
TO MIDDLE MISSISSIPPI VALLEY. THERE IS ALSO AN ELEVATED RISK OF HIGH WINDS AND
ENHANCED WILDFIRE DANGER ACROSS THE SOUTHERN HIGH PLAINS ON APRIL 27. DUE TO A
SERIES OF MID-LEVEL LOW PRESSURE SYSTEMS FORECAST OVER THE WEST THROUGH THE END
OF APRIL, AN INCREASED CHANCE OF LATE-SEASON SNOWFALL EXISTS OVER THE HIGHEST
ELEVATIONS OF THE NORTHERN TO CENTRAL ROCKIES.
HAZARDS
MODERATE RISK OF HEAVY PRECIPITATION FOR PARTS OF THE CENTRAL AND SOUTHERN
PLAINS AND MIDDLE TO LOWER MISSISSIPPI VALLEY, SAT-SUN, APR 27-28.
SLIGHT RISK OF HEAVY PRECIPITATION FOR PARTS OF THE GREAT PLAINS, MIDDLE TO
LOWER MISSISSIPPI VALLEY, AND LOWER OHIO VALLEY, SAT-FRI, APR 27-MAY 3.
MODERATE RISK OF HIGH WINDS FOR PARTS OF THE SOUTHWEST AND CENTRAL AND SOUTHERN
PLAINS, SAT, APR 27.
SLIGHT RISK OF HIGH WINDS FOR PARTS OF THE SOUTHWEST, ROCKIES, AND GREAT
PLAINS, SAT-FRI, APR 27-MAY 3.
FLOODING POSSIBLE FOR PARTS OF EASTERN TEXAS AND LOUISIANA.
DETAILED SUMMARY
FOR MONDAY APRIL 22 - FRIDAY APRIL 26:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR SATURDAY APRIL 27 - FRIDAY MAY 03: THE GEFS AND ECMWF ENSEMBLE MEANS ARE IN
GOOD AGREEMENT INDICATING AN AMPLIFIED 500-HPA TROUGH EJECTING FROM THE WEST TO
THE GREAT PLAINS BY APRIL 27. DESPITE THIS GOOD MODEL AGREEMENT ON THE EVOLVING
500-HPA PATTERN, DETERMINISTIC GFS AND ECMWF MODEL RUNS HAVE DIVERGED AT THE
SURFACE HEADING INTO WEEK-2. THE 0Z ECMWF MODEL FAVORS A FASTER SHIFTING COLD
FRONT TO THE SOUTH ACROSS THE GREAT PLAINS PRIOR TO WEEK-2, WHILE THE LATEST
GFS MODEL RUNS DEPICT A SURFACE LOW AND SHARP DRY LINE OVER KANSAS, OKLAHOMA,
AND NORTHERN TEXAS THROUGH APRIL 27. THE DETERMINISTIC GFS MODEL AND ITS
ENSEMBLE MEAN IMPLY A GREATER RISK OF THUNDERSTORMS THROUGHOUT THE SOUTHERN AND
CENTRAL GREAT PLAINS EARLY IN WEEK-2, COMPARED TO THE ECMWF MODEL. REGARDLESS
OF EXACTLY HOW THE SURFACE PATTERN EVOLVES, THE UNCALIBRATED 24-HOUR
PRECIPITATION AMOUNTS FROM THE GEFS AND ECMWF ENSEMBLE MEAN SUPPORT A
CONTINUATION OF THE MODERATE RISK (AT LEAST A 40% CHANCE) OF HEAVY
PRECIPITATION FROM THE CENTRAL TO SOUTHERN GREAT PLAINS EAST TO THE LOWER AND
MIDDLE MISSISSIPPI VALLEY ON APRIL 27 AND 28. GIVEN THE DIVERGING MODEL
SOLUTIONS, THE MODERATE RISK OF HIGH WINDS WAS REDUCED IN SPATIAL COVERAGE AND
IS ONLY VALID ON APRIL 27. ANY GUSTY WINDS ARE EXPECTED TO INCREASE THE
WILDFIRE RISK AND MAY CAUSE BLOWING DUST, ESPECIALLY OVER THE TEXAS PANHANDLE
AND WESTERN OKLAHOMA.
A PAIR OF AMPLIFIED 500-HPA TROUGHS ARE EXPECTED TO RESULT IN PERIODS OF
SNOWFALL ACROSS THE NORTHERN TO CENTRAL ROCKIES THROUGH AT LEAST THE END OF
APRIL. SINCE THE HEAVIEST SNOWFALL IS EXPECTED TO BE LIMITED TO THE HIGHEST
ELEVATIONS, A SNOW HAZARD IS NOT DEPICTED.
THE GEFS AND ECMWF ENSEMBLE MEANS FEATURE ANOTHER AMPLIFIED 500-HPA TROUGH
ENTERING THE WEST BY THE END OF APRIL, SUPPORTING SLIGHT RISKS OF HIGH WINDS
AND HEAVY PRECIPITATION VALID THROUGH MAY 3. MINOR TO MODERATE RIVER FLOODING
IS ONGOING FOR PARTS OF EASTERN TEXAS AND LOUISIANA. BASED ON THE LIKELIHOOD OF
ADDITIONAL PRECIPITATION DURING THE NEXT WEEK TO TEN DAYS, A POSSIBLE FLOODING
HAZARD CONTINUES FOR THESE AREAS THROUGH WEEK-2.
THE GFS ENSEMBLE MEAN DEPICTS A PERSISTENT 500-HPA TROUGH OVER THE ALEUTIANS
AND WESTERN ALASKA DURING MUCH OF WEEK-2. ALTHOUGH THIS WOULD FAVOR ENHANCED
ONSHORE FLOW INTO SOUTH-CENTRAL AND SOUTHEASTERN ALASKA, PRECIPITATION AMOUNTS
ARE EXPECTED TO REMAIN BELOW HAZARDS THRESHOLDS.
FORECASTER: BRAD PUGH
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