Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 242 AM EDT Tue Jun 27 2017 Valid 12Z Tue Jun 27 2017 - 12Z Thu Jun 29 2017 ...Severe thunderstorms and heavy rain possible from the central and northern plains to the Midwest today and Wednesday... A frontal system crossing the northern Rockies this morning is forecast to move into the northern and central plains this afternoon. Areas of showers and thunderstorms will accompany the system, becoming more widespread from late afternoon into Tuesday night as the system reaches the Midwest. Thunderstorms could produce severe weather and locally heavy rainfall. Please refer to products issued by the Storm Prediction Center for further details on the severe weather threat. On Wednesday, showers and storms are forecast to continue spreading east across the Midwest and the Great Lakes, with severe thunderstorms and heavy rainfall once again possible. Showers and storms will reach the Northeast by Thursday morning. Farther south, gradually increasing moisture and instability will result in scattered afternoon and evening thunderstorms increasing through mid week across the Gulf Coast and the Southeast. Temperatures are forecast to be below average across the eastern half of the country today as an upper-level trough remains in place. The coolest temperatures are forecast across the Appalachians and the lower Great Lakes, where highs are forecast to be 10 to 15 degrees below average. Farther west, temperatures will remain near or slightly above average for most areas, although the Northwest and the Southwest will see a relative respite from the extreme heat of recent days. Highs will still rise into the triple digits across much of the Southwest, however. Ryan Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php