Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 424 PM EDT Sat Oct 24 2015 Valid 00Z Sun Oct 25 2015 - 00Z Tue Oct 27 2015 ...Heavy rain and flash flooding will continue throughout the Southern Plains, Mississippi Valley, and Southeast... ...Severe thunderstorms along the Gulf coast through Monday morning.... Widespread heavy rain will continue for the southern states as a cold front advances south and east through Monday evening. Multiple days of torrential rain have pummeled Texas, where several reports are now reaching the range of 15 to 20 inches. Several observations in Oklahoma and Arkansas have exceeded 4 inches. Deep tropical moisture streaming into the Gulf is playing a significant role for the heavier rainfall. A surface low is forecast to migrate northeast along the Gulf coast through the weekend and is causing the southern tail of the cold front to surge through southern Texas and into the Gulf. The current run of models have this portion of the front tracking noticeably faster than the previous solutions. The portion of the front that will stall by early Sunday morning stretches from Houston, Texas to Monroe, Louisiana -- will act as the axis of the heaviest rain through Monday morning. Some of these thunderstorms may become severe per the Storm Prediction Center -- portions of the Gulf coast are highlighted in a slight risk. An additional 5 to 10 inches is forecast for eastern Texas, Louisiana and southern Mississippi and Alabama. Houston and the surrounding areas could see an excess of 13 inches. With these conditions in mind, flash flooding will be a significant threat across Texas and into the Deep South and portions of the Mississippi/Tennessee Valley. See the WPC excessive rainfall products and the SPC convective outlooks for more information. A line of showers and thunderstorms will continue to trek across the Great Lakes and Ohio/Tennessee Valley as the northern half of the aforementioned cold front moves through these regions. Showers will taper off the Upper Great Lakes region this evening and will spread into New England and Mid-Atlantic on Sunday. High pressure will quickly build over the East Coast in the wake of this front. The Pacific Northwest will begin to see light to moderate rain mostly along the coast by Sunday morning as a deep upper level low moves toward the region. This upper low will continue to push across the Pacific Northwest through the day. The shower activity will move farther inland across both the Pacific Northwest and Intermountain West. A few locations in the higher elevations of the northern and central Rockies could receive accumulating snow. The front will likely slow or stall on the lee side of the Rockies as high pressure tries to build in over the West. Campbell Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php