Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 405 AM EDT Thu May 14 2015 Valid 12Z Thu May 14 2015 - 12Z Sat May 16 2015 ***Pristine airmass over much of the eastern U.S.*** ***Showers and thunderstorms over the Plains*** ***Unsettled weather over parts of the western U.S.*** The East Coast, Northeast, and Ohio Valley and Great Lakes will continue to enjoy a pristine and refreshing airmass through Friday, courtesy of Canadian high pressure. Very pleasant temperatures and low humidity will make it very pleasant for outdoor activities, along with mostly sunny skies. Closer to the Gulf Coast region, it will be more humid with scattered showers and storms for Thursday and Friday near a stalled out frontal boundary. Warmer weather and higher humidity is expected to make a return to the East Coast by this weekend as the high moves offshore. For the western U.S., a deep and pronounced upper-level trough will migrate across the West Coast and become situated over the Intermountain West for the next couple of days. Widespread showers and isolated thunderstorms are expected to develop near the base of this trough as a series of mid-level shortwave disturbances cross central and southern California and eventually towards the Four-Corners region. This will bring welcomed rain and mountain snow to drought-stricken California and Nevada. Accompanying these mid-level disturbances, snow showers are likely for the higher elevations of the Sierra, Wasatch, and Colorado Rockies. Additional showers and storms are likely for the Plains and Upper Midwest as Gulf of Mexico moisture surges northward. Hamrick Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php