Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 357 AM EDT Wed Jul 04 2018 Valid 12Z Wed Jul 04 2018 - 12Z Fri Jul 06 2018 ...Severe weather possible across parts of the Upper Mississippi Valley into the central Plains today... ...Heat wave to continue through the July 4th holiday for the Eastern and Midwestern states, eventually building westward into the Southwest by the end of the week... Expect showers and thunderstorms to continue along a cold front as it presses eastward through the northern tier and the upper Midwest/Great Lakes through Thursday. Severe thunderstorms and locally heavy rainfall are possible today, and SPC has highlighted portions of the upper Mississippi Valley to the central Plains within a slight risk for severe thunderstorms. Scattered showers and storms will also be possible along and south of a quasi-stationary front across the upper Ohio Valley and the lower Great Lakes. Wet weather continues Thursday and into Friday from the Northeast to the Ohio Valley and back into the middle Mississippi Valley as the whole system sags south and eastward. Plenty of moisture streaming into the Deep South the next few days will keep the chance for showers and storms in the forecast across much of the Southeast and the Gulf Coast regions. A convective low pressure system moving slowly westward across the central Gulf Coast through tomorrow will help to enhance showers and storms from southern Mississippi to southeast Texas, where locally heavy rainfall and isolated flash flooding will be possible. The ongoing heat wave across the Eastern U.S. will continue through the July 4th holiday, with heat rebuilding across the central Plains and the Midwest as well. Heat advisories and heat warnings are in effect for much of the Midwestern states as well as portions of the Northeast. Afternoon highs in the 90s will combine with oppressive dew point temperatures, resulting in dangerous heat indices exceeding 100 degrees in some places. Uncomfortably warm and humid conditions will continue overnight as well with near or exceeding record breaking high minimums possible. The upper level ridge responsible for this heat wave should finally start to weaken by Thursday into Friday across the East, but will continue building westward into the Great Basin and the Southwest where excessive heat watches are in effect for portions of this region starting on Friday. In addition to the heat, dry conditions across the Western U.S. will result in possible fire weather conditions across much of the central Great Basin region. Red flag warnings are in effect for some locations. Santorelli Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php