714
FXUS21 KWNC 291813
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT MAY 29 2025
SYNOPSIS: FRONTAL ACTIVITY IS FORECAST TO PROGRESS THROUGH THE UPPER MIDWEST
DURING WEEK-1 AND SHIFT FURTHER SOUTHEASTWARD INTO THE MISSISSIPPI, TENNESSEE,
AND OHIO VALLEYS BY THE OUTSET OF WEEK-2 BRINGING ENHANCED CHANCES OF HEAVY
PRECIPITATION AND POTENTIALLY THUNDERSTORMS. DYNAMICAL MODELS ARE TRENDING
COOLER WITH TEMPERATURES ACROSS THE EAST, WITH EXTREME HEAT NO LONGER A
CONCERN. UPSTREAM OF THIS INITIAL FRONT, ADDITIONAL SHORTWAVE IMPULSES TIED TO
MID-LEVEL LOW PRESSURE FORECAST OVER WESTERN CANADA FAVOR INTERMITTENT CHANCES
OF HEAVY PRECIPITATION PERSISTING INTO THE MIDDLE OF THE PERIOD ACROSS THE
GREAT PLAINS AND MISSISSIPPI VALLEY. LATE IN WEEK-2, TROPICAL MOISTURE MAY MOVE
INTO PORTIONS OF FLORIDA AND THE SOUTHEAST.
HAZARDS
SLIGHT RISK OF HEAVY PRECIPITATION ACROSS PORTIONS OF THE GREAT PLAINS,
MISSISSIPPI, TENNESSEE, AND OHIO VALLEYS, SOUTHEAST, AND APPALACHIANS, FRI-MON,
JUN 6-9.
DETAILED SUMMARY
FOR SUNDAY JUNE 01 - THURSDAY JUNE 05:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR FRIDAY JUNE 06 - THURSDAY JUNE 12: DURING THE MIDDLE TO LATER PART OF
WEEK-1, A SHORTWAVE THROUGH AND ASSOCIATED COLD FRONT IS FORECAST TO MOVE
ACROSS THE CENTRAL CONUS. THE ECENS AND GEFS ARE TRENDING FASTER WITH THE
PROGRESSION OF THIS FEATURE, AND BY THE OUTSET OF WEEK-2, HEAVY PRECIPITATION
AND POTENTIALLY THUNDERSTORMS ARE PREDICTED ALONG A BAND EXTENDING FROM THE
SOUTHERN PLAINS AND LOWER MISSISSIPPI VALLEY NORTHEASTWARD THROUGH THE OHIO AND
TENNESSEE VALLEY AND APPALACHIANS, WITH RELATIVELY DRIER CONDITIONS SPREADING
INTO THE UPPER MIDWEST BEHIND THE FRONTAL PASSAGE. FOLLOWING THIS INITIAL
FRONTAL PASSAGE, AN ACTIVE CONVECTIVE PATTERN IS LIKELY TO PERSIST ACROSS
PORTIONS OF THE GREAT PLAINS AND MISSISSIPPI VALLEY AIDED BY ADDITIONAL
SHORTWAVE IMPULSES CIRCLING AROUND A MEAN TROUGH FORECAST OVER WESTERN CANADA.
THE GEFS AND ECENS PROBABILISTIC EXTREMES TOOLS (PETS) DEPICT AT LEAST A 20
PERCENT CHANCE 3-DAY PRECIPITATION TOTALS EXCEED THE 85TH CLIMATOLOGICAL
PERCENTILE AND 1-INCH THROUGHOUT THE FIRST HALF OF THE PERIOD SUPPORTING THE
SLIGHT RISK FOR HEAVY PRECIPITATION, JUN 6-9. MORE EASTERN AREAS (OHIO AND
TENNESSEE VALLEYS) ARE MORE LIKELY TO EXPERIENCE HEAVY PRECIPITATION ON DAY-8
(JUN 6) ONLY, WITH THE RISK CONTINUING UPSTREAM OVER THE GREAT PLAINS AND
MISSISSIPPI VALLEY THROUGH JUN 9.
EPISODES OF INCREASED WINDS ARE POSSIBLE ACROSS THE ROCKIES AND PLAINS TIED TO
INTERMITTENT FRONTAL PASSAGES THROUGHOUT THE PERIOD. THE ECENS AND GEFS PETS
DEPICT ENHANCED CHANCES (GREATER THAN 20 PERCENT) FOR WIND SPEEDS EXCEEDING
20-MPH ACROSS THESE AREAS, BUT FALL BELOW 20 PERCENT AT THE 25-MPH THRESHOLD.
GIVEN THESE MARGINAL SIGNALS, AND ABOVE-NORMAL PRECIPITATION FORECAST, ANY
IMPACTS FROM INCREASED WINDS ARE EXPECTED TO BE MINIMAL WITH LOW RISK FOR
WILDFIRES. THEREFORE, THE SLIGHT RISK FOR HIGH WINDS HAS BEEN DISCONTINUED.
THERE HAS BEEN A CONTINUED DOWNWARD TREND IN TEMPERATURES OVER MUCH OF THE EAST
LIKELY TIED TO THE QUICKER FRONTAL PASSAGE IN THE MODELS. THE UNCALIBRATED 0Z
ECENS AND GEFS DEPICT HIGH TEMPERATURES IN THE 70S TO LOWER 80S DEG F ACROSS
PORTIONS OF THE MIDWEST AND OHIO VALLEY, WHICH DO NOT SUPPORT THE CONTINUATION
OF THE SLIGHT RISK OF EXTREME HEAT IN YESTERDAY’S FORECAST. ALTHOUGH RIDGING
OVER NORTHEASTERN NORTH AMERICA FAVORS ABOVE-NORMAL TEMPERATURES ACROSS THE
NORTHEAST, ACTUAL TEMPERATURES ARE NOT PREDICTED TO REACH HEAT HAZARD CRITERIA.
TROPICAL MOISTURE IS FORECAST TO INCREASE ACROSS PORTIONS OF FLORIDA AND THE
SOUTHEAST LATER IN WEEK-2. THE ECENS AND GEFS PETS DEPICT DAY 12-14 (JUN 10-12)
PRECIPITATION TOTALS HAVING AT LEAST A 20 PERCENT CHANCE OF EXCEEDING THE 85TH
CLIMATOLOGICAL PERCENTILE AND 1-INCH. IT REMAINS UNCERTAIN IF THIS SURGE OF
MOISTURE WILL BE ASSOCIATED WITH A MORE ORGANIZED TROPICAL SYSTEM MOVING OUT OF
THE WESTERN CARIBBEAN AS DEPICTED IN RECENT DETERMINISTIC GFS RUNS OR A WEAKER
SURFACE WAVE (0Z ECMWF). IF TRENDS CONTINUE, A SLIGHT RISK OF HEAVY
PRECIPITATION MAY BE ADDED OVER THE SOUTHEAST IN TOMORROW’S UPDATE.
WEAK TROUGHING IS PREDICTED ACROSS THE BERING SEA AND WESTERN ALASKA DURING
WEEK-2. THIS GENERALLY FAVORS ENHANCED PROBABILITIES OF BELOW-NORMAL
TEMPERATURES ACROSS ALASKA, AND SOME INCREASED POTENTIAL FOR HEAVY
PRECIPITATION OVER SOUTHEASTERN ALASKA TIED TO ENHANCED ONSHORE FLOW. HOWEVER,
PRECIPITATION AMOUNTS ARE PREDICTED TO REMAIN BELOW HAZARDS CRITERIA.
FORECASTER: THOMAS COLLOW
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