Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 400 PM EDT Mon Jun 12 2017 Valid 00Z Tue Jun 13 2017 - 00Z Thu Jun 15 2017 ...Strong to severe thunderstorms likely over the High Plains today, shifting into the Upper Midwest on Tuesday... ...Heavy rain and flash flooding possible from the Northern Rockies eastward into the Upper Mississippi Valley today and Tuesday... ...Colder than average temperatures for the West, with snow possible at highest elevations of the Great Basin and Northern Rockies... A low pressure system and associated fronts passing through the Rockies today will move northeastward through the Northern/Central Plains and Upper Mississippi Valley through midweek. This system will lead to severe storms from the Northern Rockies to the Upper Mississippi Valley today. The highest potential for severe storms is located near the Wyoming/South Dakota/Nebraska border, where a moderate risk is in effect from the Storm Prediction Center. As the surface and upper-level lows move eastward, this threat will shift into the Northern and Central Plains and into the Upper Mississippi Valley on Tuesday. Along these slow moving frontal boundaries, heavy rain is possible, and there is a slight risk of flash flooding in effect for the Northern Rockies to Northern Plains today, as well as in the Upper Mississippi Valley. On Tuesday the main threat for flash flooding will be located in the Northern High Plains and Upper Mississippi Valley. An upper-level low located in the western U.S. is leading to colder than average temperatures and precipitation for the Great Basin, Northern Rockies, and Northern and Central High Plains. Though severe storms will be the threat on the eastern side of this system, snow is possible for higher elevations of the Great Basin and Northern Rockies, with snow chances in western Wyoming and southwest Montana lasting into Tuesday evening. Elsewhere, thunderstorms are expected over Maine today as a warm front lifts northward. There is a slight risk of severe weather in effect from the Storm Prediction Center. As a cold front moves southward, the Great Lakes and the Northeast are expecting showers and thunderstorms, reaching the Mid-Atlantic on Tuesday. Before this cold front moves through, however, temperatures will be 10-20 degrees above average in these areas. Additionally, throughout the next few days, a combination of warm Gulf moisture advecting northward and upper-level impulses will aid in producing showers and thunderstorms over parts of the Western Gulf Coast eastward into the Southeast. Some storms could produce heavy rain. Tate Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php