148 FXUS01 KWBC 271920 PMDSPD Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 320 PM EDT Mon Jul 27 2026 Valid 00Z Tue Jul 28 2026 - 00Z Thu Jul 30 2026 ...Risk for severe thunderstorms and flash flooding will spread from the Great Lakes/Ohio Valley to the Northeast over the next few days; Moderate Risk of Excessive Rainfall for the northern Mid-Atlantic/southern New England Tuesday... ...Dangerous heat wave continues over parts of southern U.S. into this week... ...Active monsoonal moisture fuels thunderstorms over the Four Corners Region, Rockies, and High Plains... Scattered to widespread thunderstorms are forecast into this evening across the Great Lakes and south into the Ohio Valley as upper-energy rounds a trough along the East Coast and frontal boundaries help force storm development. Plentiful moisture/instability as well as sufficient upper-level shear has led to an Enhanced Risk of severe weather (level 3/5) from the Storm Prediction Center. Clustering/potentially organized thunderstorms will bring a threat for damaging winds, possibly significant, as well as some large hail and possibly a tornado. Plentiful moisture in place will also bring a threat for heavy rainfall, with a Slight Risk of Excessive Rainfall (level 2/4) in place focused on eastern Illinois and northwestern Indiana, where some scattered instances of flash flooding are possible. More isolated instances will remain possible elsewhere through the region. On Tuesday, additional upper energy will help to both strengthen the trough, leading to a closed low aloft, as well as reinforce/strengthen the eastward progressing frontal system. The combination of intense upper forcing more reminiscent of Fall than Summer and warm, anomalously moist air flowing in from the Atlantic will lead to widespread, very heavy rainfall producing storms from the Carolinas north through the Appalachians, Mid-Atlantic, and into New England. The greatest concentration and potential for multiple rounds of storms is expected to focus on portions of the northern Mid-Atlantic/southern New England where a Moderate Risk of Excessive Rainfall has been included (level 3/4) for the threat of scattered to numerous and potentially significant instances of flash flooding. A broader Slight Risk (level 2/3) across the Mid-Atlantic/southern New England covers more scattered instances of flash flooding with isolated instances possible elsewhere through the region. Additional severe thunderstorms will be possible as well particularly across the Carolinas and central/southern Mid-Atlantic where the SPC has included another Slight Risk for the threat of damaging winds as well as some hail and a few tornadoes. The focus will shift a bit further to the northeast and into southern New England on Wednesday where another Slight Risk of Excessive Rainfall is in effect for additional scattered instances of flash flooding. An active Monsoonal pattern remains in place over the Four Corners Region as well as portions of the central Rockies and adjacent High Plains. Daily rounds of thunderstorms will bring locally heavy downpours with at least an isolated risk of flash flooding. There is now a Slight Risk of Excessive Rainfall in effect for portions of eastern Arizona, western/northern New Mexico, and eastern Colorado for Tuesday as suppression of the upper-ridge will allow for more widespread thunderstorms and rainfall leading to a few more scattered instances of flash flooding. Urban areas as well as burn scars will remain most sensitive to additional heavy rainfall. Elsewhere, daily thunderstorm chances will continue across portions of Florida and the Gulf Coast, with isolated flash flooding possible. A dangerous heat wave will settle over portions of the southern U.S. this week as a broad and strong upper-ridge remains in place. High temperatures in the mid- to upper 90s, locally into the low 100s, as well as oppressive humidity will lead to heat indices in the 105-115 degree range. This will result in areas of Major to Extreme HeatRisk (levels 3 and 4 out of 4), indicating a level of heat dangerous to anyone without adequate cooling or hydration. Conditions will also remain hot across much of the Interior West with highs in the 90s and Desert Southwest with highs in the 100s to low 110s. Conditions will be more variable further north over the central U.S. including the central/northern Plains where various frontal passages as well as some storm chances will help to keep temperatures down locally, but some highs in the 90s to 100 will continue, particularly across the northern Plains. Meanwhile, temperatures will be much more mild for Summer over the Northeast and Pacific Northwest with highs mainly in the 70s and 80s. Putnam Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php $$