541 
FXUS21 KWNC 201800
PMDTHR
US Hazards Outlook
NWS Climate Prediction Center College Park MD
300 PM EDT April 20 2026

SYNOPSIS: A stalled frontal boundary is favored to interact with moist 
southerly flow in week-2, increasing the potential of heavy precipitation for 
portions of the Southern Plains, the Tennessee and Lower Mississippi Valleys, 
and Southeast U.S. early in the forecast period.

HAZARDS

Slight risk of heavy precipitation for portions of the Southern Plains, the 
Tennessee and Lower Mississippi Valleys, and Southeast U.S., Tue-Wed, Apr 28-29.

DETAILED SUMMARY

FOR THURSDAY APRIL 23 - MONDAY APRIL 27: 
https://www.wpc.ncep.noaa.gov/threats/threats.php

FOR TUESDAY APRIL 28 - MONDAY MAY 04: Ensemble solutions from the ECENS and 
GEFS for 500-hPa height anomalies depict a shortwave trough moving from the 
western Contiguous U.S. (CONUS) to the Great Lakes by the outset of the week-2 
period, with accompanying surface low pressure and a trailing cold front. 
Models favor this frontal boundary to stall over the Tennessee Valley and 
weaken over time. These features are not particularly amplified but form while 
moderate return flow is established in the wake of a similar system active 
earlier in week-1. This return flow increases available moisture to the 
developing system and is favored to enhance precipitation accumulations over 
portions of the southeastern CONUS. Uncalibrated probabilities from the ECENS 
are fairly bullish, with >40% probabilities of 3-day precipitation 
accumulations exceeding 1 early in week-2. The Probabilistic Extremes Tools 
(PETs) from the GEFS and ECENS also indicate a similar region highlighted with 
>20% chance of 3-day precipitation accumulations to exceed 1. Therefore a 
slight risk of heavy precipitation is continued for portions of the Southern 
Plains, the Tennessee and Lower Mississippi Valleys, and Southeast U.S., valid 
Apr 28-29.



Surface winds are likely to be enhanced by this passing system as well, 
although guidance from the GEFS and ECENS PETs for maximum wind speed show no 
signal at the 25mph threshold, which precludes the issuance of a high wind 
hazard. However much of the Great Plains, where models do indicate a fairly 
strong signal at the 20mph threshold, is currently in drought and with dry and 
stressed vegetation. These conditions combined represent a significant risk of 
wildfire activity, and care should be taken to minimize the potential of 
wildfire initiation.



No hazards are issued over Alaska, but the typical peak of river ice breakup is 
approaching, and flooding can occur this time of year with little or no notice 
as conditions on frozen rivers can change quickly. Check with the Alaska 
Pacific River Forecast Center for the latest conditions or advisories.

FORECASTER: Danny Barandiaran 

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