Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 350 PM EDT Wed Jun 18 2025 Valid 00Z Thu Jun 19 2025 - 00Z Sat Jun 21 2025 ...Severe thunderstorms threaten the Midwest, lower Great Lakes, and Mid-Atlantic through this evening, followed by much of the Eastern Seaboard Thursday... ...Heat builds in the East through Thursday before cooling off on Friday... ...Fire weather concerns and/or significant heat for portions of the West, Rockies, & Central High Plains through Friday... The main weather maker through Friday will be a progressive upper level disturbance and cold front that brings the threat of severe thunderstorms and scattered flash flooding to much of the eastern half of the country. An intensifying wave of low pressure currently moving through the Midwest along an eastward advancing cold front will continue to foster scattered to numerous thunderstorms that are capable of producing severe weather and flash flooding from the southern Plains to the Midwest/Ohio Valley and into the Great Lakes and portions of the Mid-Atlantic through the evening hours. The highest severe weather threat lies from southeast Missouri eastward across much of Illinois, Indiana, western Ohio, and northern Kentucky, where a large complex of storms can bring strong, damaging winds and isolated tornadoes. The Appalachians, Mid-Atlantic states, and New England states will see heat increasingly build through Thursday as a ridge of high pressure briefly overspreads the region and a warm front lifts north of the area. Record high temperatures...in the mid 90s...are possible in southern New England on Thursday. Once the cold front nears the East on Thursday, more widespread severe weather would be possible within the increasingly hot and humid air mass across much of the Eastern Seaboard, particularly across the interior Northeast and the Mid-Atlantic. A waning area of thunderstorms is expected with time as a cold front leads to cooling and dries things out, clearing the Midwest by Thursday and the Mid-Atlantic and New England states by Friday. The Gulf Coast and Southeast maintain scattered showers and thunderstorms for the remainder of the work week. Across the West, a deep layer cyclone is forecast to move out of the northeast Pacific, with the center moving into the Pacific Northwest on Friday. It will drive a cold front east and south through the Pacific Northwest and Montana by Friday morning. The combination of windy and dry conditions brings an elevated fire weather threat across interior portions of the Northwest this afternoon and evening (where Red Flag Warnings are in effect), which shifts into the Great Basin on Thursday and Friday (Red Flag Warnings are in effect for much of Nevada and Utah with Fire Weather Watches in effect for much of western Colorado and northern Arizona). Significant heat expands across the West into the Central High Plains through Friday ahead of the cold front as the ridge rebuilds ahead of the deep layer cyclone. The building anomalous heat will threaten daily high temperature records across portions of the Great Basin and western South Dakota on Thursday and from Colorado north and east into Nebraska and South Dakota on Friday. High temperatures will remain 100F+ for the Desert Southwest through the remainder of the work week (Death Valley could exceed 120F) where Extreme Heat Warnings remain in effect. Heat Advisories remain in effect for southern and western fringes of the Big Bend of western Texas this afternoon and evening where high temperatures of 100-110F are forecast. Miller/Roth Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php