741
FXUS21 KWNC 181828
PMDTHR
FXUS21 KWNC 181825
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EST APRIL 18 2024
SYNOPSIS: A MULTI-DAY RISK OF THUNDERSTORMS, HIGH WINDS, AND ELEVATED WILDFIRE
DANGER IS FORECAST FROM THE GREAT PLAINS EAST TO THE MISSISSIPPI VALLEY DURING
LATE APRIL THROUGH THE BEGINNING OF MAY. A LATE-SEASON SNOWFALL IS EXPECTED
AT THE HIGHEST ELEVATIONS OF THE SIERRA NEVADA MOUNTAINS ALONG WITH THE
NORTHERN TO CENTRAL ROCKIES. ALTHOUGH ABOVE-NORMAL TEMPERATURES ARE FAVORED
ACROSS THE CENTRAL AND EASTERN U.S. DURING WEEK-2, HAZARDOUS HEAT IS NOT
ANTICIPATED AT THIS TIME OF YEAR.
HAZARDS
MODERATE RISK OF HEAVY PRECIPITATION FOR PARTS OF THE CENTRAL AND SOUTHERN
PLAINS AND MIDDLE TO LOWER MISSISSIPPI VALLEY, FRI-SUN, APR 26-28.
SLIGHT RISK OF HEAVY PRECIPITATION FOR PARTS OF THE GREAT PLAINS, MIDDLE TO
LOWER MISSISSIPPI VALLEY, AND LOWER OHIO VALLEY, FRI-THU, APR 26-MAY 2.
MODERATE RISK OF HIGH WINDS FOR PARTS OF THE SOUTHWEST, CENTRAL AND SOUTHERN
ROCKIES, AND CENTRAL AND SOUTHERN PLAINS, FRI-SUN, APR 26-28.
SLIGHT RISK OF HIGH WINDS FOR PARTS OF THE SOUTHWEST, ROCKIES, AND GREAT
PLAINS, FRI-THU, APR 26-MAY 2.
FLOODING POSSIBLE ACROSS EASTERN TEXAS AND THE LOWER MISSISSIPPI VALLEY.
DETAILED SUMMARY
FOR SUNDAY APRIL 21 - THURSDAY APRIL 25:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR FRIDAY APRIL 26 - THURSDAY MAY : LATER NEXT WEEK, A WARM FRONT IS
FORECAST TO SHIFT NORTHWARD ACROSS THE GREAT PLAINS AND MISSISSIPPI VALLEY.
FOR THE SECOND CONSECUTIVE DAY, THE GEFS AND ECMWF ENSEMBLE MEANS ARE IN
GOOD AGREEMENT INDICATING AN AMPLIFIED 500-HPA TROUGH PROGRESSING EAST TO THE
SOUTHWEST FROM APRIL 26 TO 28. THE UPSTREAM 500-HPA TROUGH AND CLIMATOLOGY
WOULD FAVOR A MULTI-DAY RISK OF THUNDERSTORM INITIATION ALONG THE DRY LINE.
THE LARGE-SCALE ENVIRONMENT IS LIKELY TO RESULT IN PERIODS OF THUNDERSTORMS
WITH LOCALLY HEAVY RAINFALL FROM THE SOUTHERN TO CENTRAL GREAT PLAINS EAST
TO THE MISSISSIPPI VALLEY. BASED ON THE 500-HPA HEIGHT EVOLUTION, THE GEFS
WOULD FAVOR THE HIGHEST CHANCE TO THE NORTH SUCH AS KANSAS AND MISSOURI WHILE
THE ECMWF ENSEMBLE MEAN TARGETS THE SOUTHERN GREAT PLAINS. A MODEL CONSENSUS
OF UNCALIBRATED 24-HOUR PRECIPITATION AMOUNTS WAS USED TO DEFINE THE MODERATE
RISK OF HEAVY PRECIPITATION. DUE TO CONTINUED SPREAD AMONG THE ENSEMBLE MEANS
ON ONE OR MORE SURFACE LOW TRACKS, A BROADER SLIGHT RISK OF HEAVY
PRECIPITATION IS DEPICTED AND IS VALID THROUGH THE ENTIRETY OF WEEK-2.
ALONG WITH THE INCREASED RISK OF THUNDERSTORMS WITH HEAVY RAINFALL, THE
LONGWAVE PATTERN IS LIKELY TO LEAD TO LEESIDE CYCLOGENESIS ACROSS THE CENTRAL
AND SOUTHERN HIGH PLAINS. BASED ON PATTERN RECOGNITION AND WIND SPEED FORECASTS
FROM DETERMINISTIC MODEL RUNS, A MODERATE RISK OF HIGH WINDS IS POSTED FOR
THOSE AREAS ALONG WITH PARTS OF THE SOUTHWEST APR 26 TO 28. SIMILAR TO THE
HEAVY PRECIPITATION HAZARD, MODEL GUIDANCE SUPPORTS THE CONTINUATION OF A
SLIGHT RISK OF HIGH WINDS THROUGH MAY 2. THE GUSTY WINDS COULD CAUSE BLOWING
DUST FROM SOUTHEASTERN COLORADO AND NEW MEXICO EAST TO KANSAS, OKLAHOMA, AND
THE TEXAS PANHANDLE. THE AMPLIFIED 500-HPA TROUGH IS EXPECTED TO RESULT IN AT
LEAST A BRIEF PERIOD OF HEAVY SNOWFALL, INITIALLY OVER THE SIERRA NEVADA
MOUNTAINS AND THEN OVERSPREADING THE NORTHERN TO CENTRAL ROCKIES DURING LATE
APRIL. SINCE ANY HEAVY SNOWFALL WOULD LIKELY BE LIMITED TO THE HIGHEST
ELEVATIONS, A SNOW HAZARD IS NOT DEPICTED.
THE GFS ENSEMBLE MEAN DEPICTS A PERSISTENT 500-HPA TROUGH OVER THE ALEUTIANS
AND WESTERN ALASKA DURING 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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