Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 239 AM EDT Sun Jul 23 2017 Valid 12Z Sun Jul 23 2017 - 12Z Tue Jul 25 2017 ...Flash flooding and severe weather will be possible over portions of Mid-Atlantic states this weekend... ...Dangerous heat is expected to continue for the central Plains and Middle Mississippi Valley to the Mid-Atlantic coast through the weekend... ...Localized flooding possible across the Southwest and southern and central Rockies over the next few days... A frontal boundary will slowly push across the Mid Atlantic and Ohio Valley, becoming a focus for showers and thunderstorms. A hot and humid air mass in place across much of the region will support strong to severe thunderstorms and localized heavy rainfall on Sunday. Parts of the central Appalachians could see some flash flooding as the storms move over already saturated soils. The front will linger across the Mid Atlantic for Monday with showers and thunderstorms spreading into the Northeast but no severe weather or flash flooding is expected at this time. Further west, the front will sag southward across the southern Plains and Tennessee Valley with showers and thunderstorms expected across much of the Southeast. Dangerous heat will continue across parts of the central U.S. and southern Mid Atlantic on Sunday. High temperatures will reach into the mid and upper 90s to near 100 degrees across parts of the southern Plains, mid Mississippi Valley, and into the southern Mid Atlantic. Those temperatures combined with very high dewpoints will lead to heat index values of 100 to 115 across much of the region. At least some relief should arrive on Monday as the front nears with showers and thunderstorms expected. Monsoonal moisture along with daytime heating will trigger thunderstorms across the Southwest and the southern half of the Rockies on Sunday. Heavy downpours associated with these thunderstorms could lead to localized flash flooding. The flash flood threat will be a bit more focused across Arizona for Monday. Krekeler Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php