Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 411 AM EDT Sat May 9 2015 Valid 12Z Sat May 9 2015 - 12Z Mon May 11 2015 ***Heavy rain and severe storms for the Plains*** ***Late season snow for the Rockies and Dakotas*** ***Tropics getting an early start*** Severe thunderstorms and heavy rainfall are expected to make weather headlines over the next couple of days from Texas to the Midwest states. Multiple thunderstorm complexes are forecast to develop in the vicinity of a slow-moving frontal boundary and developing surface low that will be situated across the central Plains and eventually moving towards the Upper Midwest. A dry line over western Texas will also provide enough forcing for thunderstorm development. Localized flash flooding will also be a concern where these thunderstorm complexes become the most persistent. Within the large scale trough over the western U.S., an anomalous upper level low crossing the Intermountain West will result in unseasonably cold conditions from the Great Basin to the western High Plains. Heavy snow is likely for parts of Colorado, Wyoming, and western Nebraska and South Dakota as deep moisture is advected westward on the northern side of the main surface low. The opposite is true for the eastern half of the country this weekend where temperatures will be above average for early May. The first named tropical system of the year, Ana, is expected to slowly meander towards the southeast coast this weekend, with periods of heavy rain and gusty winds. By Monday, this feature will begin moving northward under the influence of a trough out to the west, and weaken as it moves over land. The National Hurricane Center and local weather forecast offices have additional information on this storm. Hamrick Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php