Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 358 AM EDT Tue Jul 11 2017 Valid 12Z Tue Jul 11 2017 - 12Z Thu Jul 13 2017 ...Severe weather and heavy rainfall possible across portions of the Ohio Valley and the lower Great Lakes... ...Severe weather and heavy rainfall threat to increase by Tuesday and Wednesday from the Northern Plains to the Upper Mississippi Valley and into the Great Lakes... Showers and thunderstorms are forecast across the north-central U.S. as a weak low pressure travels along an eastward progressing frontal boundary. The strongest convection is expected to generate mainly near and ahead of the low center itself. Conditions will be favorable for some of the storms to become severe, possibly even producing periods of heavy rainfall. Both WPC and SPC have highlighted slight risks in the Ohio Valley and parts of the lower Great Lakes. Please refer to the SPC convective outlooks and the WPC excessive rainfall outlooks for additional information on the risks. A second area of low pressure is forecast to drop into the Northern Plains; which will bring another frontal boundary through the northern High Plains and Upper Midwest over the next couple of days. Another round of showers and thunderstorms will likely develop and track from the Upper Mississippi Valley/Upper Midwest to the Great Lakes region. Severe thunderstorms will continue to be possible. Across much of the West hot and dry conditions will persist. Diurnally driven monsoonal moisture will continue to bring scattered showers and thunderstorms to parts of the Southwest and into the central Rockies. Meanwhile, return flow around high pressure over the western Atlantic keeps showers and storms in the forecast across the Southeast and Gulf Coast states through the middle of the week. Campbell/Santorelli Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php