Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 401 PM EDT Fri Jul 17 2020 Valid 00Z Sat Jul 18 2020 - 00Z Mon Jul 20 2020 ...Severe weather and heavy rain across the Northern Plains and Upper Midwest through Saturday... ...Summer heat to spread from the Plains to the East Coast this weekend... A cold front currently in Canada will migrate south and initiate thunderstorms (some severe) over the Northern Plains and Upper Midwest tonight through Saturday. These storms may congeal into a squall line over northwestern Minnesota, which will likely produce heavy rain and damaging winds. The Storm Prediction Center issued a Slight Risk with embedded Enhanced and Moderate Risks of severe weather as a result. Despite this system moving fairly quickly through the Northern Plains, rain rates may be high enough to produce flash flooding, therefore a Slight Risk of Excessive Rain is in place over eastern North Dakota through northwestern Minnesota for tonight. The severe weather and flash flooding threats will stretch into the Upper Great Lakes on Saturday as the squall line and associated cold front continue their march across region. Above average temperatures and humidity currently over the Great Plains will spread eastward through the Midwest on Saturday before entering the Mid-Atlantic and Northeast on Sunday. The forecasted heat and humidity lead to the issuance of excessive heat warnings and heat advisories for parts of the Great Plains and Upper/Middle Mississppi Valley. The heat will not relent at night as low temperatures are expected to remain in the 70s. The maximum heat index forecast for this weekend indicates many places across the Great Plains and Mississippi Valley exceeding 105 degrees with some isolated places reaching 110 degrees. Excessive heat watches are in effect for Delaware extending up through Philadelphia and much of New Jersey in advance of Sunday. Kebede Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php