Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 400 PM EDT Mon Jun 17 2019 Valid 00Z Tue Jun 18 2019 - 00Z Thu Jun 20 2019 ...Flash flooding is forecast Monday with thunderstorms from the Middle Mississippi Valley to the Ohio Valley and northern Mid-Atlantic... ...Severe weather possible for High Plains on Monday and Southern/Central Plains on Tuesday... Over the next couple days, a stationary front will linger across the Middle/Lower Mississippi and Ohio Valleys and into the northern Mid-Atlantic. Scattered thunderstorms are expected along this front and southward into the Tennessee Valley and Southeast. Flash flooding is possible particularly along the front--Flood and Flash Flood Watches are in effect from the Middle Mississippi Valley eastward through the Ohio Valley and parts of the Mid-Atlantic, and there is also a Slight Risk of excessive rainfall outlooked there through Monday night. Some severe weather is also possible in these areas, with Marginal to Slight Risks in place from the Storm Prediction Center. The main focus for heavy rain and flash flooding should shift a bit southward on Tuesday into the Southern Appalachians, while remaining in eastern portions of the Mid-Atlantic region. Another frontal system is forecast to move through the Plains and Upper Midwest, eventually hooking up with a front tracking through the northwestern U.S. This combined with some upper-level impulses moving through will lead to thunderstorms for the central U.S. as well. The Central High Plains could see both severe weather and flash flooding today, and Slight Risks of both are in place. Severe weather is also possible in the Southern High Plains. As the front moves south and east by Tuesday, convection should focus in the Central and Southern Plains. A Slight Risk of severe weather is outlooked for parts of Texas, Oklahoma, and Kansas, while the focus for flash flooding is a bit farther north and east in parts of Oklahoma, the Central Plains, and western portions of the Middle Mississippi Valley region. These risks shift east on Wednesday. The Central Great Basin and Four Corners region could see scattered thunderstorms as well on Monday and Tuesday. An isolated flood or flash flood is possible there, particularly Monday. With all these thunderstorms cooling down temperatures, high temperatures are expected to be at or below average in most areas over the next couple of days. The main exception will be in the northwestern U.S., where the Northern/Central Great Basin to northern California, could see highs 5 to 15 degrees above average. Tate Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php