164 FXUS01 KWBC 121838 PMDSPD Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 236 PM EDT Wed Aug 12 2026 Valid 00Z Thu Aug 13 2026 - 00Z Sat Aug 15 2026 ...Dangerous heat continues from the central/southern Plains into the Southeast... ...An active pattern will keep the threat of heavy rainfall/flash flooding in the forecast throughout much of the Midwest and western U.S... A heatwave has begun to settle in from the central/southern Plains east through the Southeast as an upper-high strengthens overhead. Forecast highs in the upper 90s to low 100s along with high humidity will lead to heat indices in the 105-115 degree range. Some potential record-tying/breaking temperatures are possible with many areas forecast to see their hottest temperatures so far this year or even in the past few years. Morning lows only dropping into the mid-70s to low 80s will provide little relief from the heat overnight. Widespread Major to Extreme HeatRisk (levels 3 and 4 out of 4) is expected indicating oppressive heat dangerous to anyone without access to adequate cooling or hydration. Unfortunately, the heatwave is forecast to continue well beyond the current forecast period through at least mid-August. Meanwhile, scattered to widespread storms continue across the Midwest to Ohio Valley/central Appalachians under stronger upper-flow and along a quasi-stationary frontal boundary to the north of the upper-high. A Moderate Risk of Excessive Rainfall (level 3/4) remains in effect into this evening (Wednesday) across portions of eastern Indiana into central Kentucky where additional rounds of rainfall over already saturated grounds from storms the days before may lead to scattered to numerous instances of flash flooding. A Slight Risk (level 2/4) is in place more broadly through the region for more scattered instances of flash flooding. The Storm Prediction Center also maintains a Slight Risk of severe weather (level 2/5) mainly for the threat of some damaging winds through the rest of this evening. Storms will continue the next couple of days as this stagnant pattern remains in place, with a Slight Risk of Excessive Rainfall throughout the region Thursday and then focused on the Upper Mississippi Valley for Friday, as scattered instances of flash flooding remain a concern. An active storm pattern is also present along the western side of the upper-ridge from the Southwest/Four Corners region north into the Great Basin, Rockies, and adjacent areas of the northern/central High Plains. The greatest storm coverage and influx of moisture Pacific moisture rounding the upper-ridge, and subsequent threat for heavy rainfall/flash flooding, will vary day to day as the flow adjusts ahead of an upper-trough entering the Northwest. However, at least isolated instances of flash flooding can be expected through the next few days. Through this evening, the locally higher threat/Slight Risk covers portions of the Southwest/Four Corners region. This risk broadens on Thursday to include portions of the Great Basin as well as the central Rockies and northern/central High Plains. For Friday, a Slight Risk is in place for the central High Plains. In addition to flash flooding, the SPC has also included a Slight Risk of severe weather over portions of the central to northern Plains for the rest of this evening for the threat of large hail and damaging winds. Elsewhere, daily thunderstorm chances can be expected for Florida mainly through Thursday. Some showers and thunderstorms are also possible through New England over the next couple of days. Most of the country will see around or even below average, more mild temperatures outside of the heatwave over the South. Forecast highs will generally be in the 70s and 80s across the northern Plains to Upper Midwest and New England as well as throughout most of the West outside of the Deserts, where highs will still be below average but into the 90s to low 100s. Putnam Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php $$