Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 211 PM EDT Sat Jul 14 2018 Valid 00Z Sun Jul 15 2018 - 00Z Tue Jul 17 2018 ...Monsoonal moisture to bring heavy rain for the Desert Southwest, Great Basin and central/southern Rockies... ...Showers and thunderstorms expected across the northern Plains... ...Heavy rain expected for the middle Mississippi Valley and Southeast... ...Heat wave will impact the Pacific Northwest... Scattered thunderstorms that have loomed over the Desert Southwest each afternoon the last few days is expected throughout this weekend. Monsoonal moisture and daytime heating will lead to scattered to numerous thunderstorms in the afternoon and evening. By Sunday, this activity will continue across the Southwest and portions of the Great Basin in addition to increasing in the southern and central Rockies. Localized flash flooding will be a concern due to terrain and especially in flood prone areas. See WPC's excessive rainfall outlook for more details. A slow moving front will stretch from the Great Lakes to the Plains will be the focal point for showers and thunderstorms over the next few days. Ample moisture from the Gulf of Mexico will be transported to this area and fuel convective activity particularly in the afternoon and evening this weekend and into early next week. A marginal risk of flash flooding is possible mostly over parts of the Ohio Valley and middle Mississippi Valley. Additionally, a marginal risk of severe thunderstorms is also possible in this region. By Sunday, the front will weaken as another incoming front will sweep across the Plains and Mississippi Valley. Scattered showers and thunderstorms are expected to persist mostly in the Ohio Valley and the mid/lower Mississippi Valley. A quasi-stationary front will be draped across the Southeast through the weekend. With plenty of moisture on tap and instability from daytime heating, showers and thunderstorms will increase throughout the day the Southeast with the front aiding in fueling these thunderstorms. A marginal risk of flash flooding will be possible through Monday. Parts of the Pacific Northwest and northern California can expect high temperatures in the upper 90s and over 100 over the next few days. Consequently, heat advisories and excessive heat watches/warnings are in place in these regions. With the hot and dry conditions, along with the possibility of dry thunderstorms, fire weather will be a concern in some areas of the Pacific Northwest and Intermountain West. This heat wave is expected to continue well into next week. Reinhart Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php