Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 351 PM EDT Mon Aug 27 2018 Valid 00Z Tue Aug 28 2018 - 00Z Thu Aug 30 2018 ...There is a slight risk of severe thunderstorms over parts of the Northern Plains into the Upper Great Lakes... ...Heavy rain possible over parts of the Upper/Middle Mississippi Valley into the Upper Great Lakes... ...Accumulating wet snow forecast for parts of the highest elevations of the Northern Rockies... ...Air quality alert for parts of the San Joaquin Valley and parts of Oregon... A front extending from the Upper Great Lakes/Upper Mississippi Valley southwestward to the Great Basin will move eastward to parts of Northern New England/Great Lakes southwestward to the Southern High Plains by Wednesday. Showers and thunderstorms will develop along and near the boundary from parts of the Upper Great Lakes/Upper Mississippi Valley into parts of the Northern Plains that will move eastward to the Great Lakes/Western Ohio Valley into the Middle Mississippi Valley and the Central High Plains by Wednesday. As the front moves into parts of New England, showers and thunderstorms will develop over the area early Wednesday morning into Wednesday. In addition, a cold upper-level trough will aid in producing rain and highest elevation snow over parts of the Northern Rockies that would include parts of Yellowstone National Park ending by Tuesday morning. Rain will also develop over parts of the Northern Intermountain Region eastward to parts of the Northern Plains ending overnight Monday into Tuesday morning. Furthermore, even though there is a deep upper-level trough over parts of the West, air quality alert is in effect for parts of the San Joaquin Valley and parts of Oregon. Meanwhile, upper-level energy and moisture will aid in producing showers and thunderstorms over parts of the Southern Plains overnight Monday and Tuesday night. Additionally, upper-level energy will aid in producing showers and thunderstorms over parts of the Lower Great Lakes into parts of the Northeast through Tuesday evening. Daytime heating will also aid in producing showers and thunderstorms over parts of the Appalachians during the late afternoon into evening on Monday and Tuesday. Elsewhere, tropical moisture over the Southeast westward to the Western Gulf Coast will aid in producing showers and thunderstorms over the region through Wednesday. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php