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FXUS21 KWNC 061851

PMDTHR

US Hazards Outlook

NWS Climate Prediction Center College Park MD

300 PM EDT May 06 2024



SYNOPSIS: Mid-level high pressure over the West Coast and mostly zonal flow 

over the contiguous U.S. (CONUS) results in a relatively tranquil period of 

weather for week-2. At the outset of week-2 a stalled frontal boundary over the 

Gulf Coast leads to the potential for heavy precipitation for portions of the 

Southeast U.S.



HAZARDS



Slight risk for heavy precipitation for portions of the Southeast U.S., 

Tue-Thu, May 14-16.



DETAILED SUMMARY



FOR THURSDAY MAY 09 - MONDAY MAY 13: 

https://www.wpc.ncep.noaa.gov/threats/threats.php



FOR TUESDAY MAY 14 - MONDAY MAY 20: At the outset of week-2 ensemble models 

favor moderate ridging (troughing) over the West Coast (Great Lakes) as 

depicted by 500-hPa height anomalies. The GEFS favors a much deeper trough over 

the East with the axis centered over the Appalachians, while the ECMWF features 

a much shallower trough over the Great Plains. Model solutions dampen both 

features over the course of week-2, with weak positive height anomalies and 

mostly zonal flow over the contiguous U.S. (CONUS) by the end of the forecast 

period.







While there are significant differences among model solutions in the timing and 

location, there is good consensus between various models with regard to the 

potential for heavy precipitation. Both the GEFS and ECMWF Probabilistic 

Extremes Tools (PETs) indicate at least a 20% probability of 3-day accumulated 

precipitation exceeding the 85th percentile and 1 inch for portions of the 

Southeast U.S for May 14-16. The ECMWF is especially bullish, with much wider 

coverage of the area indicated for 1 inch total and over 2 inches possible for 

portions of the Louisiana coast east to the Big Bend of Florida. There are some 

indications that heavy rainfall may persist beyond May 16, but model solutions 

diverge even more so, thus the hazard posted does not extend further into 

week-2. Although much of this area highlighted for a risk for heavy 

precipitation has been in a rain deficit and soils are becoming parched, most 

of the precipitation is anticipated to be able to infiltrate into the soil 

column due to soils in the area being sandy. Therefore a potential flooding 

hazard is not issued at this time, although localized ponding and urban flash 

flooding is possible.







In Alaska, as we move into the middle of May snowmelt season is underway and 

frozen rivers are beginning to break up. This leads to the potential for river 

flooding related to ice-jams. We continue to monitor the situation but 

currently there are no indications of impending major river break-ups or 

serious threat of ice-jamming so no flooding-related hazards are posted at this 

time.



FORECASTER: Danny Barandiaran 



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