Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 407 AM EDT Wed Jul 17 2024 Valid 12Z Wed Jul 17 2024 - 12Z Fri Jul 19 2024 ...There is a Slight Risk of severe thunderstorms over parts of the Mid-Atlantic to New England on Wednesday... ...There is a Slight Risk of excessive rainfall over parts of the Mid-Atlantic, Southern Plains/Lower Mississippi Valley, and Southern High Plains/Southern Rockies on Wednesday and over the southern Mid-Atlantic and Southern Rockies on Thursday... ...There are Excessive Heat Warnings/Watches and Heat Advisories over parts of the Pacific Northwest and parts of the Southern Plains to the Lower Mississippi Valley/Southeast, and New England Coast to the Mid-Atlantic Coast... A front extending from the Lower Great Lakes/Ohio Valley across the Middle Mississippi Valley into the Southern Plains will move slowly off the Northeast and Mid-Atlantic Coast by Friday. Also, on Friday, the southern half of the boundary will linger near the Southeast and across the Gulf Coast States. The boundary will produce showers and severe thunderstorms over parts of Northern New England to the Mid-Atlantic. Therefore, the SPC has issued a Slight Risk (level 2/5) of severe thunderstorms over parts of Northern New England to the Mid-Atlantic through Thursday morning. The hazards associated with these thunderstorms are frequent lightning, severe thunderstorm wind gusts and a minimal threat for hail and tornadoes. In addition, the showers and thunderstorms will create heavy rain over parts of the Mid-Atlantic. Therefore, the WPC has issued a Slight Risk (level 2/4) of excessive rainfall over parts of the Mid-Atlantic through Thursday morning. The associated heavy rain will create mainly localized areas of flash flooding, with urban areas, roads, small streams, and low-lying areas the most vulnerable. A Second area of heavy rain will develop along the front over parts of the Southern Plains/Lower Mississippi Valley. Therefore, the WPC has issued a Slight Risk (level 2/4) of excessive rainfall over parts of the Southern Plains/Lower Mississippi Valley through Thursday morning. The associated heavy rain will create mainly localized areas of flash flooding, with urban areas, roads, small streams, and low-lying areas the most vulnerable. Moreover, a third area of heavy rain will develop near the boundary over parts of the Southern High Plains/Southern Rockies. Therefore, the WPC has issued a Slight Risk (level 2/4) of excessive rainfall over parts of the Southern High Plains/Southern Rockies through Thursday morning. The associated heavy rain will create mainly localized areas of flash flooding, with urban areas, roads, small streams, and low-lying areas the most vulnerable. Furthermore, moisture over the Southwest and daytime heating will produce showers and thunderstorms over parts of the Great Basin and Southwest late afternoon into late evening. Additionally, on Wednesday, upper-level impulses and tropical moisture will produce showers and thunderstorms over parts of the Southeast. On Thursday, as the front moves southeastward, showers and strong to severe thunderstorms will develop over parts of the southern Mid-Atlantic. Therefore, the SPC has issued a Marginal Risk (level 1/5) of severe thunderstorms over parts of the over parts of the southern Mid-Atlantic from Thursday through Friday morning. The hazards associated with these thunderstorms are frequent lightning, severe thunderstorm wind gusts, and a minimal threat of hail and tornadoes. The showers and thunderstorms will create heavy rain over parts of the southern Mid-Atlantic. Therefore, the WPC has issued a Slight Risk (level 2/4) of excessive rainfall over parts of the southern Mid-Atlantic from Thursday through Friday morning. The associated heavy rain will create mainly localized areas of flash flooding, with urban areas, roads, small streams, and low-lying areas the most vulnerable. A second area of showers and strong to severe thunderstorms will develop over parts of the Central/Southern High Plains as moisture interacts with upper-level impulses. Therefore, the SPC has issued a Marginal Risk (level 1/5) of severe thunderstorms over parts of the over parts of the southern Mid-Atlantic from Thursday through Friday morning. The hazards associated with these thunderstorms are frequent lightning, severe thunderstorm wind gusts, hail, and a minimal threat of tornadoes. Likewise, the showers and thunderstorms will create heavy rain over parts of the Southern Rockies. Therefore, the WPC has issued a Slight Risk (level 2/4) of excessive rainfall over parts of the Southern Rockies from Thursday through Friday morning. The associated heavy rain will create mainly localized areas of flash flooding, with urban areas, roads, small streams, low-lying areas, and burn scars the most vulnerable. Meanwhile, upper-level ridging will build over the Northwest, spawning Heat Advisories over the region from Wednesday into Friday. Moreover, a flat upper-level ridge extending from the Lower Mississippi Valley eastward to the Mid-Atlantic and Southeast will aid in creating a major to extreme HeatRisk for the East Coast part of the country. The heat has prompted Excessive Heat Warnings/Watches and Heat Advisories over parts of the Southern Plains to the Lower Mississippi Valley/Southeast. A second area of heat has prompted Excessive Heat Warnings/Watches and Heat Advisories extending from the Mid-Atlantic to parts of New England. On Wednesday, the near-record temperatures and high humidity suggest Major to Extreme HeatRisk conditions for portions of the East. Extremely dangerous and potentially deadly heat, particularly for urban areas in the Southeast and East Coast, are forecast. Many daily record highs are possible for the East Coast, and numerous warm overnight lows will provide little relief from the heat overnight. Heat stress will build rapidly for those without adequate cooling or hydration. However, a strong cold front will bring relief as it sweeps across most of the Eastern U.S. from Wednesday into Thursday. This front will be accompanied by showers and thunderstorms. Some thunderstorms could be severe, especially in the Northeast. Ziegenfelder Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php