Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 312 AM EDT Thu Jul 13 2017 Valid 12Z Thu Jul 13 2017 - 12Z Sat Jul 15 2017 ...Severe weather expected from the Great Lakes to the Mid-Atlantic... ...Heavy rainfall will be possible from the Plains to the lower Great Lakes... ...Hot and humid weather expected for the Mid-Atlantic in addition to hot weather across the West... Across the eastern U.S., a slow moving frontal boundary will ignite showers and thunderstorms along and ahead of it through the next few days. On Thursday, the frontal boundary will stretch from New England and into the central Plains with convection expected throughout these regions. As the front slowly sinks in the Great Lakes, plenty of moisture and instability will be present. Thus, severe weather in addition to flash flooding will be possible mostly in the middle Mississippi Valley, lower Great Lakes, and portions of the Ohio Valley. Cooler temperatures behind the front can be expected. The cold front will move farther south on Friday, sweeping across the Mid-Atlantic and will arrive in the Carolinas and Southeast by Saturday with showers and thunderstorms moving along and ahead of the front. Flash flooding will continue to be a concern primarily for the Ohio Valley on Friday. Severe weather will also be a potential threat for the Mid-Atlantic on Friday and Saturday. See the Storm Prediction Center for more specific information on the severe weather. Elsewhere, the remnants of tropical depression Four will move westward across Florida on Thursday. These remnants will trigger showers and thunderstorms especially across South Florida. By Friday and Saturday, the westward trek of the remains from tropical Depression 4 will continue into the Gulf of Mexico. These remains will bring deep tropical moisture and daytime heating will trigger the production of showers and thunderstorms across the Gulf Coast states. Locally heavy rainfall will be possible. Ahead of the aforementioned cold front, very warm and humid conditions will be possible especially for the Mid-Atlantic as temperatures are expected to be about 10 degrees above normal on Thursday. However, with such high humidity being present, heat index values will be well above 100 degrees. These uncomfortable conditions will also be felt from the Ohio Valley to the central Plains and southward across the Carolinas and Southeast. By Friday and Saturday, as the cold front moves through these regions cooler conditions will follow and high temperatures will be below average. Hot and dry conditions are expected for the western U.S. as high pressure aloft continues to dominate over this area. Temperatures hitting the century mark or above can be expected throughout the short term period from the central Great Basin to the northern Plains. Reinhart Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php