Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 343 PM EDT Fri Sep 27 2013 Valid 00Z Sat Sep 28 2013 - 00Z Mon Sep 30 2013 ...Heavy rain for the Pacific Northwest and parts of the ArkLaTex Region.... ...There is a slight risk of severe thunderstorms over parts of the Central/Southern Plains... A front extending from the Upper Mississippi Valley to the Southern Rockies will move eastward to the Great Lakes/Southern Plains by Sunday morning. Showers and thunderstorm will develop along and ahead of the boundary over the Central/Southern Plains moving to the Middle Mississippi Valley/Southern Plains by Sunday. Snow will wind down over the Northern/Central Rockies on Friday night. Rain will develop over parts of the Northern/Central Plains, likewise, moving eastward to the Great Lakes/Ohio Valley and parts of the Tennessee/Middle Mississippi Valleys by Sunday. Meanwhile, a deep upper-level trough will move onshore over the Pacific Northwest pulling multiple boundaries into the area. Onshore flow associated with the system will stream a plume of moisture into the Northwest that will produce moderate to heavy rain over the Pacific Northwest and as far inland as parts of the Northern Rockies through Sunday morning. Some snow will fall at the higher elevations of the Northern Rockies overnight Friday into Saturday morning. Elsewhere, onshore flow off the Atlantic will produce scattered showers and thunderstorms along the Southeast Coast through Sunday. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php