Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 346 PM EDT Tue Sep 24 2019 Valid 00Z Wed Sep 25 2019 - 00Z Fri Sep 27 2019 ...Heavy rain and flash flooding possible through Wednesday in parts of Arizona... ...Severe thunderstorms expected to develop this afternoon and evening from the Central Plains to the Upper Mississippi Valley... Showers and thunderstorms have continued today across parts of southern Arizona due to a mixture of abundant moisture and a potent upper-level low. Localized heavy rainfall and flash flooding will be possible in southern Arizona through tonight, and will be most likely in southeast Arizona. WPC has issued a Moderate Risk of flash flooding and excessive rainfall through tonight. On Wednesday, localized heavy rainfall and flash flooding will be possible over a broader portion of the Desert Southwest. Elsewhere, a cold front will push across the Plains and into the Great Lakes by Wednesday. The front will lead to thunderstorm development from the Central Plains to the Upper Mississippi Valley this afternoon and tonight. Some of these storms could be severe, with damaging wind, large hail, frequent lightning, and a few tornadoes. The Storm Prediction Center has issued an Enhanced Risk of severe thunderstorms in parts of Iowa, Minnesota, and Wisconsin. A stalled front in the vicinity of Oklahoma and Arkansas will continue to be a focus for slow-moving showers and thunderstorms from this afternoon into Wednesday. Flash flooding will be possible, and Flash Flood Watches have been issued for portions of these two states. Temperatures will be above average across much of the country over the next few days. The main exceptions will be over the Desert Southwest, associated with the increased rain and cloud cover, and in the Northwest and Northern Plains behind the aforementioned cold front. Hot conditions will affect parts of coastal California and the central Valley through Wednesday, where some Heat Advisories have been posted. Red Flag Warnings were also in effect in portions of California for the potential of critical fire weather conditions. By Thursday, the heat will be building in the Southeast, where highs in the 90s may break some records. Lamers Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php