


Prognostic Meteorological Discussion
Issued by NWS
Issued by NWS
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950 FXUS01 KWBC 230717 PMDSPD Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 317 AM EDT Sat Aug 23 2025 Valid 12Z Sat Aug 23 2025 - 12Z Mon Aug 25 2025 ...Excessive rainfall concerns for the Southeast and Four Corners this weekend... ...Extreme heat over the Southwest through Sunday; expands in Northwest through early next week... A stalled surface front draped across the central Gulf and Southeast Coasts will continue to be the focus for scattered showers and thunderstorms today. The heaviest rainfall is expected to occur along the South Carolina, Georgia and north Florida coasts, where plentiful moisture will interact with an area of surface low pressure and the surface front to enhance rain rates. A high-end slight risk (at least 25% chance) of excessive rainfall leading to flash flooding is in effect for the Georgia Coast where anywhere between an additional 1-2 inches, with isolated higher amounts, are possible. Soils in this region are particularly sensitive from ongoing rainfall (1-3" areal average since Friday afternoon) along the stationary front. Elsewhere, embedded shortwave energy within an upper-ridge will produce monsoon activity in the Four Corners region this weekend. A surface front draped up against the Central/Southern Rockies may produce heavy rainfall today. A slight risk (at least 15% chance) of excessive rainfall is in effect for portions of south-central Colorado and north-central New Mexico. The development of another surface front over portions of the Central/Southern High Plains will likely focus and expand monsoon moisture over parts of western Kansas on Sunday, where another slight risk is in effect. An additional slight risk is in effect for parts of southern Utah and northern Arizona on Sunday, where scattered to isolated instances of heavy rainfall may produce flash flooding over vulnerable land types--especially slot canyons. This same upper ridge will fuel a heat wave, which is expected across much of the Western U.S. through this weekend, with the most intense and long-lasting heat across the Desert Southwest into the San Joaquin Valley. Extreme Heat Warnings and Watches are in effect from portions of Arizona through Washington. This type of heat will be dangerous, posing a threat to anyone without effective cooling and adequate hydration. Numerous daily high temperature records are likely. For many areas, there will be little nighttime relief from the extreme heat, with overnight lows remaining well above normal. Numerous nighttime temperature records are likely. Extreme heat is dangerous even at night when temperatures don`t cool down. Without A/C or cooling, the body can`t recover, increasing the risk of heat illness. The most extreme heat will begin to subside across the Southwest and California after Sunday, but for areas in the Pacific Northwest, the extreme heat is likely to continue into the middle of next week before finally waning. Kebede Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php $$