Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 315 AM EDT Tue May 02 2017 Valid 12Z Tue May 02 2017 - 12Z Thu May 04 2017 ...Another round of potentially heavy rain expected from the southern and central plains to the Mississippi and Ohio valleys... ...Warming temperatures expected for much of the western U.S... A frontal system that has moved off much of the East Coast will continue to bring showers and a few thunderstorms to portions of New England today, before moving offshore tonight. Locally heavy rain will be possible, especially this morning before the cold front passes through the region. Farther west, scattered showers are expected today across much of the Great Lakes as an upper-level trough passes overhead. An upper-level trough crossing the northern Rockies early this morning is forecast to move into the central U.S. later today. As this occurs, an area of low pressure is expected to develop along a surface frontal boundary across the southern plains later today. The developing low pressure system is forecast to move east toward the lower Mississippi valley on Wednesday, and into the Ohio valley by Thursday morning. Numerous showers and thunderstorms are expected in association with the system, starting across portions of the southern and central plains late today into tonight, and spreading east into the Mississippi and Ohio valleys on Wednesday. These showers and storms are expected to bring additional heavy rainfall to areas where the ground is still saturated from recent heavy rains. Thus, flash flooding will be possible for some areas. Severe thunderstorms are also possible on Wednesday across portions of the western and central Gulf Coast. Please refer to products issued by the Storm Prediction Center for further details on the severe weather threat. Farther west, rain showers will be possible today across portions of the Pacific Northwest. These should come to an end by Wednesday, however, as high pressure aloft builds over much of the West. The building ridge of high pressure will result in rising temperatures across much of the West. Afternoon highs on Wednesday are forecast to be 10 to 20 degrees above average from much of the West Coast to the Great Basin and portions of the northern Rockies. The warm temperatures will expand on Thursday, with some areas of the northwest and northern Intermountain Region surpassing 20 degrees above average. Ryan Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php