809
FXUS21 KWNC 241748
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT APRIL 24 2025
SYNOPSIS: AT THE OUTSET OF WEEK-2 SURFACE LOW PRESSURE IS FORECAST TO BE NEAR
NEW ENGLAND, WITH A TRAILING COLD FRONT EXTENDING ACROSS THE EAST-CENTRAL
CONTIGUOUS U.S. (CONUS) AND THE SOUTHERN PLAINS. THIS FRONT IS FORECAST TO
BECOME STATIONARY, WHICH FAVORS ENHANCED CHANCES OF HEAVY PRECIPITATION AND
THUNDERSTORMS ACROSS PORTIONS OF THIS REGION CONTINUING THROUGH MUCH OF WEEK-2.
BROAD MID-LEVEL HIGH PRESSURE IS FORECAST TO DEVELOP ACROSS THE CONUS LATER IN
WEEK-2, FAVORING INCREASED CHANCES FOR ABOVE-NORMAL TEMPERATURES OVER MANY
AREAS.
HAZARDS
SLIGHT RISK OF HEAVY PRECIPITATION FOR PORTIONS OF THE SOUTHERN AND CENTRAL
PLAINS, AND THE LOWER MISSISSIPPI VALLEY, FRI-TUE, MAY 2-6.
POSSIBLE FLOODING FOR THE LOWER MISSISSIPPI RIVER.
DETAILED SUMMARY
FOR SUNDAY APRIL 27 - THURSDAY MAY 01:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR FRIDAY MAY 02 - THURSDAY MAY 08: LATE IN WEEK-1, SURFACE LOW PRESSURE IS
FORECAST TO TRACK ACROSS THE GREAT LAKES AREA, WITH AN ASSOCIATED TRAILING COLD
FRONT DRAPED ACROSS THE EAST-CENTRAL CONUS, SERVING AS A FOCUS FOR CONTINUED
INCREASED CHANCES OF HEAVY PRECIPITATION AND THUNDERSTORMS. THIS FRONT IS
EXPECTED TO STALL VERY EARLY IN WEEK-2, WITH THE HEAVIER PRECIPITATION FAVORED
ACROSS PORTIONS OF THE SOUTHERN AND CENTRAL PLAINS, AND THE LOWER MISSISSIPPI
VALLEY, WHERE A SLIGHT RISK OF HEAVY PRECIPITATION IS POSTED FOR MAY 2-6. THIS
MEANS THERE IS AT LEAST A 20 PERCENT CHANCE OF RAINFALL AMOUNTS EXCEEDING THE
85TH CLIMATOLOGICAL PERCENTILE AND 1-INCH. THIS SLIGHT RISK AREA IS SUPPORTED
BY THE PROBABILISTIC EXTREMES TOOL (PET) PRECIPITATION GUIDANCE FROM PRIMARILY
THE ECENS SOLUTION (AND TO A LESSER DEGREE FROM THE GEFS AND CANM), AND BY RAW
0Z ECENS PRECIPITATION FORECASTS. THE RAW 0Z ECENS PRECIPITATION FORECASTS ARE
MORE BULLISH THAN THE OTHER MODEL GUIDANCE AND WOULD SUPPORT A MODERATE RISK OF
HEAVY PRECIPITATION FOR PORTIONS OF THIS REGION. HOWEVER, THE GEFS AND CANM
SOLUTIONS ARE SOMEWHAT DIFFERENT TODAY, WHICH PRECLUDES THE POSTING OF A
MODERATE RISK AREA. IF THE GEFS COMES ON BOARD WITH THE ECENS TOMORROW, A
MODERATE RISK MAY BE NEEDED. COMPARED TO YESTERDAY, THERE IS A SLIGHT WESTWARD
AND NORTHWARD DISPLACEMENT OF THE HEAVY RAINFALL AREA OVER THE SOUTH-CENTRAL
CONUS.
A POSSIBLE FLOODING HAZARD REMAINS POSTED ACROSS THE LOWER MISSISSIPPI RIVER
GIVEN THE POTENTIAL FOR NEW AND RENEWED RISES IN WATER LEVELS DURING WEEK-2
TIED TO ANY ADDITIONAL RAINFALL OVER THE REGION ASSOCIATED WITH THE STATIONARY
FRONT, AS WELL AS RUNOFF FROM RAINFALL UPSTREAM. MAIN CHANNELS ARE ALREADY VERY
HIGH, AND THUS ARE UNLIKELY TO HAVE LARGE RESPONSES TO ADDITIONAL
PRECIPITATION. REGARDLESS, TRIBUTARIES AND STREAMS ACROSS THIS REGION
(INCLUDING THE SOUTHERN PLAINS) WILL CONTINUE TO BE SUSCEPTIBLE TO RENEWED
FLOODING OR FLASH FLOODING IF ADDITIONAL RAINFALL OCCURS. LATE SPRING IS THE
PEAK TIME FOR FLASH FLOODING IN TEXAS, DUE IN PART TO SLOW-MOVING THUNDERSTORMS.
THOUGH NO WIND HAZARDS ARE POSTED TODAY, ONE AREA OF CONCERN IS THE SOUTHWEST,
IN ADVANCE OF A MID-LEVEL, SOUTHERN STREAM TROUGH. TYPICALLY DURING THE SPRING,
AS THE DESERTS HEAT UP, STRONGER WINDS ROUNDING THE BASE OF APPROACHING
MID-LEVEL TROUGHS ARE MIXED DOWN TO THE SURFACE RESULTING IN VERY GUSTY WINDS
THAT OCCASIONALLY PRODUCE SIGNIFICANT DAMAGE. THE ECENS AND GEFS PETS DEPICT
WIND SPEEDS OF AT LEAST 20 MPH IN PARTS OF THE SOUTHWEST, WHICH MAY BE
UNDERDONE GIVEN THE INHERENT NATURE OF ENSEMBLE SMOOTHING.
A COLD FRONT MOVING OFF THE NORTHEAST COAST EARLY IN WEEK-2 FAVORS A REDUCTION
IN TEMPERATURES OVER THE GREAT LAKES AND NORTHEAST. THE ECENS PET STILL DEPICTS
PARTS OF THE SOUTHERN MID-ATLANTIC AND SOUTHEAST TO HAVE AT LEAST A 40 PERCENT
CHANCE MAXIMUM TEMPERATURES WOULD EXCEED THE 85TH PERCENTILE ON MAY 2, THOUGH
TODAY’S NATIONAL BLEND OF MODELS (NBM) DOES NOT SHOW NEAR-RECORD OR RECORD
TEMPERATURES OVER THE EAST. A GENERAL TREND TOWARD MORE BROAD RIDGING AND A
PATTERN TYPICAL OF LATE-SPRING IS FORECAST TO EMERGE OVER MUCH OF THE CONUS
LATER IN WEEK-2.
TROUGHING FORECAST ACROSS ALASKA FAVORS INCREASED CHANCES FOR INCREASED ONSHORE
FLOW AND ABOVE-NORMAL PRECIPITATION OVER THE SOUTHEASTERN PART OF THE STATE,
THOUGH FORECASTED PRECIPITATION AMOUNTS OF 1-2 INCHES FALL SHORT OF HAZARDS
THRESHOLDS. BELOW-NORMAL TEMPERATURES FORECAST OVER MANY AREAS MAY FAVOR A
SLIGHT DELAY IN SEASONAL RIVER ICE BREAKUP. HOWEVER, AS TEMPERATURES CONTINUE
TO WARM, THE EVENTUAL RIVER ICE BREAKUP MAY LEAD TO ICE JAMS AND ASSOCIATED
UPSTREAM FLOODING IN THE COMING WEEKS.
FORECASTER: ANTHONY ARTUSA
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