Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 359 PM EDT Thu Aug 08 2019 Valid 00Z Fri Aug 09 2019 - 00Z Sun Aug 11 2019 ...Additional heavy rain along with the threat of flash flooding will exist through early Friday from southeast Kansas and northeast Oklahoma east across southwest Missouri and northwest Arkansas... ...Severe thunderstorms and locally heavy rainfall will be possible across the lower Great Lakes, Ohio Valley, and the Northeast through this evening, and across the northern High Plains on Friday... ...Cooler temperatures and rain are expected for the Northwest, but Heat Advisories remain in effect across portions of the south-central U.S as a heatwave persists... There is expected to be another round of heavy rainfall overnight and early Friday across parts of the central Plains and into the lower and middle Mississippi Valley as heavy showers and thunderstorm redevelop north of a quasi-stationary frontal zone. Accounting for the heavy rainfall last night and this morning, there is potential for multi-day rainfall totals of several inches from southeast Kansas and northeast Oklahoma over toward southwest Missouri and northwest Arkansas. Areas of flash flooding are expected, and especially where heavy rains have already occurred over the last 24 hours. As a result, the Weather Prediction Center has highlighted a Moderate Risk of excessive rainfall for these areas. Unsettled weather is likely through this evening along and ahead of a cold front for the lower Great Lakes, Ohio Valley, and parts of the Northeast. Scattered areas of heavy showers and thunderstorms are expected including the threat of severe weather. The Storm Prediction Center has highlighted parts of this region in a Slight Risk of severe weather going into the overnight hours. On Friday, the Slight Risk of severe weather will shift to the northern High Plains as multiple areas of low pressure eject eastward along with a frontal zone. Locally heavy rainfall can be expected here. Farther south, showers and thunderstorms are likely along a portion of the same frontal zone impacting the middle to lower Mississippi Valley and the Tennessee Valley. Some additional concerns for flash flooding cannot be ruled out for any of these areas. Upper-level ridging across the south-central U.S. will result in very hot and humid conditions from the southern Plains east to the lower Mississippi Valley where heat advisories are in effect and daytime highs could exceed 100 degrees. Meanwhile, monsoonal moisture on the west side of this ridge will also continue to contribute to diurnally driven showers and thunderstorms from the Four Corners into the Rockies. Across the Northwest, a break in the heat is expected as an upper-level low offshore of the West Coast moves inland by Saturday and brings a substantial increase in cloud-cover along with a threat of moderate to locally heavy rain. This system will bring temperatures down to near normal on Friday, and below normal by Saturday. Meanwhile, hot and dry conditions will continue across parts of the central Great Basin through Friday leading to an elevated risk for fire weather, but cooler conditions will arrive this weekend and lessen the fire danger. Orrison Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php