Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 359 PM EDT Tue Jul 17 2018 Valid 00Z Wed Jul 18 2018 - 00Z Fri Jul 20 2018 ...There is a slight risk of severe thunderstorms over parts of the Central Plains and the Northeast States... ...Heavy rain possible over portions of Arizona, Northern New Mexico and Southern Colorado, as well as parts of the northern High Plains and the Northeastern states... ...Hot temperatures expected across the southern Plains and southern Mississippi Valley, as well as for the portions of the western states... A large frontal system currently extends from New England southward across the Central Appalachians and westward through the Tennessee Valley into the Southern Plains. The eastern portion of this front will continue to shift eastward off shore into the Atlantic through Wednesday. Meanwhile, the southern extent of the front will continue to push southward into the southeast through the remainder of the week, while a low pressure system deepens across the southern Plains and begins to transition northeast as a warm front for the remainder of the week as well. During this time, shower and thunderstorm development is expected along the frontal boundary. A slight chance of severe thunderstorm potential is in place along New England ahead of the front for this afternoon and tonight. Excessive rain and flash flooding is also possible in this area today and tonight before the front shifts out over the Atlantic Ocean. Meanwhile, upper level energy and a low pressure system over the Northern Plains is also resulting in the develpment of strong showers and thunderstorms. A slight chance for both excessive rain and severe thunderstorm activity will remain in place across portions of the Central and Northern Plains through tomorrow, transitioning eastward into the Mid and Upper Mississippi Valley by Thursday. The best threat for severe weather and excessive rainfall will be during the afternoon and evening hours during peak daytime heating. A strong pull of warm air from the Gulf of Mexico is making its way into the southern Plains and Lower Missisippi Valley ahead of the above mentioned frontal boundary. This is leading to excessive heat, with heat advisories in place in portions of this area through mid week. Out west, much of the Pacific Northwest, California, and the western portion of the Intermountain West are experiencing very dry conditions, which is aiding in boosting temperatures across this region. Wind is also adding concerns as well. Heat advisories, warnings, and Red Flag Warnings are all in effect across portions of these areas through at least midweek. wix Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php