Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 406 PM EDT Tue Aug 14 2018 Valid 00Z Wed Aug 15 2018 - 00Z Fri Aug 17 2018 ...Heavy rain possible across New England and the northern Mid Atlantic... ...Heavy rain and thunderstorms possible across portions of the plains through tonight, shifting eastward into the Mississippi Valley for Wednesday... ...Fire weather concerns continue across the West with the threat of dry thunderstorms sparking new wildfires... A quasi-stationary front extending from parts of the Northeast southward across coastal parts of the Mid-Atlantic into parts of the Southeast will slowly dissipate by Wednesday morning, with most showers and thunderstorms expected to taper off. However, the driving surface low pressure center will remain over the Northeast during this time, coupling with a strong upper level low. This will advect large amounts of moisture inland across the Northeast, resulting in widespread rainfall. The Weather Prediction Center has continued a slight risk of excessive rainfall and flash flooding across much of the Northeast and into the northern Mid Atlantic through tonight. Flash Flood Watches and Warnings are also currently in effect across this area. Meanwhile, another low pressure system will continue to gain strength across the Central Plains as it slowly shifts eastward towards the Middle Mississippi Valley by Wednesday evening. A strong surge of warm, moist air from the Gulf of Mexico will clash with colder air moving in from the north, resulting in a frontal boundary and creating the epicenter for showers and thunderstorms over the next several days. The Weather Prediction Center has outlined a large portion of the Southern and Central Plains, eastward into the Mid and Lower Mississippi Valley as being in a slight risk for excessive rainfall through tonight. This risk area will shift eastward, extending from the Low/Middle Mississippi Valley and into the western Ohio Valley during the day Wednesday, and then into the Great Lakes region by Thursday. Flash Flood Watches are also currently in effect for eastern Oklahoma and northwest Arkansas. Yet another frontal boundary is currently draped across the Central and Northern Plains this afternoon. This will couple with an upper level system to bring forcing, instability and moisture to portions of this region. The Storm Prediction Center has outlined Northeast Wyoming and far southeast Montana as being in a slight risk for severe weather today. This slight risk region will shift eastward for Wednesday, settling across western Nebraska. A marginal risk of severe weather is also in effect in the outlying vicinity. Elsewhere, fire weather concerns continue across the West. While monsoonal moisture moves into the Southwest, dry thunderstorms will extend northward across much of the West, potentially sparking new wildfires. A large portion of Central California as well as much of the Pacific Northwest, Northern Great Basin, and Northern Rockies are under an Air Quality Alert due to smoke from ongoing wildfires. Red Flag Warnings are also in effect across portions of Northern California and southern Oregon, as well as much of northern Nevada and far Southeast Idaho as the threat of dry thunderstorms looms through mid week. Wix Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php