Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 341 PM EDT Wed Jun 17 2015 Valid 00Z Thu Jun 18 2015 - 00Z Sat Jun 20 2015 ...Tropical Depression Bill forecast to spread heavy rainfall and the potential for flash flooding northward across portions of the southern plains and middle Mississippi valley... ...Showers and thunderstorms, some possibly severe, expected from the Ohio valley to the Mid-Atlantic, and for portions of the High Plains... Tropical Depression Bill is moving northward across north Texas this afternoon, and is gradually expected to make a northeastward turn tonight into Thursday. Bill is bringing very heavy rainfall to portions of Texas and southern Oklahoma today, and heavy rain will spread northeastward along with the low pressure center. Heavy rain is expected to spread over the eastern half of Oklahoma and western Arkansas tonight and will begin to move into the southern Missouri on Thursday. Rainfall amounts of 4 to 8 inches are forecast over eastern Texas and eastern Oklahoma, with localized amounts of 12 inches. 3 to 6 inches of rain are forecast over western Arkansas and southern Missouri. These rainfall amounts will result in the potential for flash flooding over many areas. Severe weather is also possible through tonight over portions of the Arklatex region. Please refer to the latest WPC Tropical Cyclone Advisory for the latest information on Bill. On Friday Bill is forecast to become post-tropical as it moves into the middle Mississippi valley. Deep moisture will spread into the Mid-Mississippi and Ohio valley and will result in the potential for widespread showers and thunderstorms as the moisture interacts with a stationary frontal boundary. The threat of heavy rain and flash flooding will continue to accompany the system. A wave of low pressure along a frontal boundary will bring showers and thunderstorms to portions of the central Appalachians and Mid-Atlantic region this evening into tonight. The Storm Prediction Center is forecasting a slight risk of severe thunderstorms for these areas. Farther west, a wave of low pressure moving from eastern Wyoming into the central High Plains tonight will cause showers and thunderstorms to develop. The Storm Prediction Center is forecasting a slight risk of severe thunderstorms across these areas through tonight. On Friday, a low pressure system crossing the northern Rockies will begin to move into the northern plain. As a result, showers and thunderstorms are expected across the northern plains on Friday. Ryan Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php