Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 422 AM EDT Tue Apr 28 2020 Valid 12Z Tue Apr 28 2020 - 12Z Thu Apr 30 2020 ...There is an embedded enhanced and moderate risk of severe thunderstorms over parts of the Southern Plains into parts of the Lower Mississippi Valley... ...There is a slight risk of severe thunderstorms from parts of the Mississippi Valley to parts of the Central/Southern Plains... ...There is a slight risk of excessive rainfall over parts of the Southern Plains into the Lower Mississippi Valley... ...Temperatures will be 10 to 20 degrees above average over the Southwest into parts of the Great Basin... A developing strong storm over the Plains/Mississippi Valley will produce severe thunderstorms over of the parts of Mississippi Valley to parts of the Central/Southern Plains producing potential damaging wind over the region on Tuesday. The thunderstorms will produce damaging squall lines with perhaps hurricane force wind and wind-driven hail. In addition, there is a slight risk of excessive rainfall over parts of the Southern Plains into the Lower Mississippi Valley that will produce scattered areas of flash flooding that will be mainly localized. Some of the storms may produce 2 inches of rain in 45 minutes. The aforementioned storm will become the main weather story across the central to eastern U.S. during the next few days. This system is forecast to begin intensifying across the Plains on Tuesday as an upper-level trough dives into the Northern and Central Plains while ingesting very warm and moisture air from the Gulf of Mexico. By Wednesday, the highest threat of heavy rain and thunderstorms should be pushing east of the Lower Mississippi Valley toward the interior Southeast. In addition, rain and some thunderstorms will be spreading across the Great Lakes ahead of the intensifying storm. Many areas of the East Coast will begin to see rain arriving later on Wednesday. Meanwhile, much above average temperatures will continue in the Desert Southwest as upper-level ridging lingers over the region through Wednesday. Forecast high temperatures for much of California, the Great Basin eastward to western Texas will be in the 80s and 90s while many areas in the Desert Southwest will surpass the century mark. These readings will challenge daily record high temperatures. Excessive Heat Warnings remain in effect for a large portion of the Desert Southwest. Meanwhile, Northern/Central High Plains and nearby Rockies behind a developing low pressure system will be at risk for wildfires through Wednesday morning. In the meantime, the very warm air will spill into the southern Plains on Tuesday before cooler air arriving on Wednesday behind a cold front. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php