Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 410 PM EDT Thu Jun 19 2014 Valid 00Z Fri Jun 20 2014 - 00Z Sun Jun 22 2014 ...Active weather continues across the central Plains and Mississippi Valley... ...Stormy weather will be expected for the Ohio Valley and Mid-Atlantic... Active weather continues along a quasi stationary boundary in place from the Central Plains to the Mid Atlantic. Return flow off the Gulf of Mexico will supply ample moisture ahead of a cold front pushing through the Central Plains leading to widespread convection. Heavy rain may lead to flash flooding across portions of the Upper Mississippi Valley where heavy rains also fell yesterday. Some thunderstorms could be severe across portions of the Upper Mississippi Valley, Southern Mid Atlantic, and Texas Panhandle. The stationary boundary will drift southward into the Southern Mid Atlantic tomorrow shifting the focus for precipitation further south. An upper level low over Montana will drift into Central Canada by tomorrow. Widespread showers and thunderstorms are expected ahead of an occluded front pushing slowly through the Northern Plains toward the Great Lakes. Intensity and coverage will decrease as the upper low weakens. Another upper level low will swing toward the Pacific Northwest/British Columbia coast by Thursday. At the surface, a frontal boundary will begin to move onshore by Thursday evening and an increased coverage of showers will occur through Friday morning. Once the frontal boundary moves across the Rockies and Intermountain West, scattered showers will remain and any of the heavier precipitation will remain along the coastline of British Columbia. This front does not have the impressive upper level support as the previous system did. Consequently, the precipitation will have much less coverage along the Rockies and High Plains. Diurnally driven thunderstorms along the sea breeze will continue across Florida. Most of the activity will be confined to the south and central regions of the state. West Texas will also scattered thunderstorms firing off throughout the short term period. Krekeler/Fanning Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php