Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 343 PM EDT Mon Jun 18 2018 Valid 00Z Tue Jun 19 2018 - 00Z Thu Jun 21 2018 ...Heavy rain and strong thunderstorms extending from the central Plains to the Northeast and Mid Atlantic... ...Heavy rains and flash flooding possible for the Texas coast into southern and southeastern Texas... ...Dangerous heat continues for the Midwest and Ohio Valley extending eastward into the Northeast and Mid Atlantic today... A slow-moving frontal boundary that helped bring historic rains to portions of the upper Midwest and upper Great Lakes region will continue to drop south, settling into the mid Mississippi and Ohio valleys overnight. There the front is expected to remain into Thursday, providing the focus for multiple rounds of showers and thunderstorms that will be encouraged by a series of weak low pressure systems moving along the front. Some of these storms may be strong to severe and produce heavy to excessive rainfall amounts. Heat advisories are in place from eastern Kansas into portions of the southern Great Lakes region and Ohio valley, as the combination of daytime temperatures climbing into the 90s along with high humidity will produce heat indices of 100 degrees or more in some locations this afternoon. Excessive heat warnings remain in place across some of the metropolitan regions, including the Chicago and St Louis metros. Temperatures are expected to come down some on Tuesday, especially across the southern Great Lakes region. Hot and humid conditions are forecast to remain in place further to the south. By Wednesday however, increasing clouds associated with developing storms along the front, are expected to help limit daytime highs across much of the region. Further to the east, heat advisories are in effect today for portions of the Northeast and northern Mid-Atlantic today, where heat indices are expected to climb into the upper 90s to over 100 in some locations. However, the heat will be short-lived across much of Upstate New York and northern New England as the leading edge of the aforementioned front pushes southeast from southeastern Canada this evening. This will bring cooler temperatures back into the region, but not before showers and thunderstorms move across the region this afternoon and evening. Some of these storms may be strong to severe and produce heavy to excessive rainfall amounts. The front will continue to drop further to the south into the Mid Atlantic region on Tuesday, where it will continue to provide the focus for showers and thunderstorms and potentially severe weather. Cooler temperatures will gradually filter south through the Northeast into the northern Mid Atlantic region Tuesday into Wednesday. Further to the south, summertime conditions are expected to persist across the Southeast and southern Mid-Atlantic. Daytime highs are expected to climb well into the 90s to near 100 across the central into the eastern Carolinas Monday through Wednesday. A deep tropical moisture plume accompanying an upper level low and weak surface trough moving out of the western Gulf of Mexico is expected to produce showers and thunderstorms, with heavy rainfall and flash flooding possible over the next few days from the Texas coast inland into southeast and southern Texas. This system has the potential to produce several inches of rain across portions of the region. Out west, an upper level low will continue produce unsettled conditions and cooler temperatures as it moves from the northern Rockies and Intermountain West late Monday into Tuesday. This system is expected to move out into the northern and central High Plains on Tuesday, raising the threat for organized storms over the central Plains Tuesday afternoon and evening. These storms may be strong to severe and produce heavy to excessive rainfall amounts. Pereira Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php