Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 359 AM EDT Sat Jul 21 2018 Valid 12Z Sat Jul 21 2018 - 12Z Mon Jul 23 2018 ...Slight risk of severe weather and flash flooding possible in the eastern U.S.... ...Severe weather possible from the northern High Plains to portions of the Upper Midwest... ...Above normal temperatures to continue across the southern Plains along with the Pacific Northwest... The frontal system that has been impacting the Mississippi, Tennessee and Ohio Valleys will push westward across the Ohio and Tennessee Valleys along the Appalachians. Showers and thunderstorms will be possible along this front as copious amounts of moisture and instability are in place for such activity. The Storm Prediction Center has indicated that severe weather will be a concern especially in the Southeast and the southern Appalachians. Meanwhile, a surface low that has formed off the coast of the Carolinas will also be pushing northward along the Mid-Atlantic and into the Northeast. This system will also be a focal point for heavy rainfall particularly in the Mid-Atlantic today. Thus, flash flooding will be a threat for the Mid-Atlantic and parts of the Ohio Valley on Saturday. By Sunday, the heavy rain in the low pressure along the East Coast will shift toward the New England coast where flash flooding will once again be a concern. Showers and thunderstorms can also be expected for the Ohio Valley, Mid-Atlantic, and Southeast. A frontal system will slide across the northern High Plains today where a line of thunderstorms can be expected. A slight risk of severe weather is possible especially in eastern Montana/Wyoming and western portions of the Dakotas. As this system moves into the northern Plains, higher amounts of moisture available will lead to heavier rainfall in the Dakotas. This line of storms may also produce severe weather--where a slight risk has been highlighted in the northern Plains and a small portion of the Upper Midwest. A marginal risk of flooding will be possible for Colorado where some thunderstorms could produce flash flooding in favorable terrain. Dangerous heat remains in place across the southern Plains, Southwest and Pacific Northwest and will persist through the weekend and into Monday. Excessive heat warnings and heat advisories are in place across these regions. High temperatures will reach well over the century mark across Texas and Oklahoma through this weekend--with areas near the Dallas/Fort Worth region reaching to 110! Portions of the Red River Valley could have heat index values above 110 degrees. Portions of the Pacific Northwest will also continue to experience above normal temperatures--especially by the end of the weekend where temperatures could reach the mid to upper 90s and even reach over 100 in some areas. Reinhart Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php