Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 421 PM EDT Sat Jul 17 2021 Valid 00Z Sun Jul 18 2021 - 00Z Tue Jul 20 2021 ...There is a Moderate Risk of excessive rainfall over parts of the Northeast through Sunday morning... ...There is a Slight Risk of severe thunderstorms over parts of the Northeast/Mid-Atlantic and the parts of the Northern/Central High Plains through Sunday morning... ...Excessive heat throughout the Northern Plains and Intermountain West; Potential for dry lightning over Central and Northern California on Sunday could lead to conditions capable of producing wildfires... A slow-moving front will meander eastward between the Lower Great Lakes and Southern Plains, then move off the Northeast Coast by Monday while producing scattered showers and thunderstorms. The front will intersect a very warm and humid airmass, sparking numerous thunderstorms and making heavy rain. The WPC has issued a Moderate Risk of excessive rainfall with these thunderstorms over parts of the Northeast. The associated heavy rain will create numerous areas of flash flooding. Furthermore, many streams may flood, potentially affecting larger rivers through Sunday morning. Moreover, the SPC has issued a Slight Risk of severe thunderstorms over parts of the Northeast and Mid-Atlantic through Sunday morning. The hazards associated with these thunderstorms are frequent lightning, severe thunderstorm wind gusts, hail, and a few tornadoes. In the meantime, the western end of the front will be quasi-stationary through Monday over parts of the Northwest to the Northern/Central High Plains. The boundary will aid in producing showers and thunderstorms over the region through Sunday morning. The SPC has issued a Slight Risk of severe thunderstorms over the parts of the Northern/Central High Plains through Sunday morning. The hazards associated with these thunderstorms are frequent lightning, severe thunderstorm wind gusts, hail, and a few tornadoes. Meanwhile, an upper-level building ridge over the western U.S. will lead to hot temperatures that will be well above average across the Northern Plains and Northern Great Basin for the next several days. Highs into the triple digits can be expected throughout the Intermountain West to the Northern High Plains. Therefore, Excessive Heat Warnings/Watches and Heat Advisories have been issued. Meanwhile, high temperatures into the low-to-mid 90s are forecast throughout the Northern Plains and parts of the Upper Mississippi Valley. This heatwave will exacerbate the severe to the exceptional drought currently found across the region, which in combination can make for an environment ripe for wildfires to spread uncontrollably. Additionally, dry lightning could be a concern for Northern and Central California parts on Sunday as monsoonal moisture enters from the south but produces very little rain. If thunderstorms do form, extremely dry fuels struck by lightning could produce new fires. Therefore, fire Weather Watches have been issued. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php