Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 322 AM EDT Wed Jun 9 2021 Valid 12Z Wed Jun 9 2021 - 12Z Fri Jun 11 2021 ...Locally significant flash flooding expected to continue for portions of Arkansas and Mississippi on Wednesday... ...Persistent heat for much of the Great Plains along with threats for severe thunderstorms across the northern High Plains into eastern Montana... The overall weather pattern will be rather slow to change through the middle to end of the week across most of the nation. A large upper level ridge anchored over the Plains will keep a frontal boundary from making much eastern progress across the Intermountain West and the Rockies through early Thursday, before making more progress on Friday. Meanwhile, a cold front will make slow progress southward across the Great Lakes and Northeast U.S. through the end of the week, bringing some welcomed relief to the recent hot weather for these areas by Thursday and especially on Friday. It will remain hot and humid with July-like conditions across the remainder of the central and southern U.S. with highs running 5 to 15+ degrees above seasonal averages in many cases, with the greatest anomalies across the Northern Plains and the Upper Midwest. It will be pleasantly cool for this time of year across the West Coast region since an upper level trough will be situated across the eastern Pacific. Additional rounds of heavy rainfall are in the forecast from the Deep South to the Mid-Atlantic region, with scattered maxima of 1 to 3 inch totals with locally higher amounts possible over the next two days from Kentucky to North Carolina. The greatest concern is expected to be across southeastern Arkansas and northern Mississippi, where a High Risk of excessive rainfall is in effect for Wednesday and Wednesday night. This region has been hammered by torrential rain and flooding over the past 1-2 days, and the additional 2 to 4 inch rainfall totals on saturated ground will greatly increase the flash flood threat. Scattered to numerous showers and storms are also expected across portions of Idaho and western Montana near a slow moving front, and some 1 inch rainfall totals may become realized. Strong to severe thunderstorms will be possible across portions of Montana on Wednesday per the latest convective outlook from the Storm Prediction Center, and a more organized severe weather threat is likely across the Northern Plains as a strong disturbance intercepts an increasingly unstable airmass. There will also be elevated fire weather concerns across much of the Intermountain West, owing to a favorable combination of gusty winds and very low humidity levels, along with ongoing severe drought. Hamrick Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php