Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 358 PM EDT Tue Jul 30 2019 Valid 00Z Wed Jul 31 2019 - 00Z Fri Aug 02 2019 ...Monsoonal moisture returning to the Southwest will foster numerous showers and thunderstorms along with locally heavy rainfall and concerns for flash flooding... ...Much above average temperatures are expected for the central and southern High Plains... ...Showers and thunderstorms will advance into the Eastern U.S. as a cold front moves slowly eastward... ...A slow-moving cold front will support widespread showers and thunderstorms from the western and central Gulf Coast northeast up across the Tennessee Valley, Ohio Valley and into portions of Mid-Atlantic and Northeast this evening and again on Wednesday. Out ahead of this cold front, the airmass will be hot and humid with afternoon temperatures well into the 90s which will be as much as 5 to 10 degrees above normal, and especially up across areas of the Northeast. In the wake of this front, an area of high pressure moving from the upper Midwest into the Great Lakes will spread below average temperatures and lower humidity across a large area of the broader Midwest over the next couple of days. This cooler and drier area of high pressure is expected to reach the Ohio Valley and Northeast on Thursday as the front settles south down into the Tennessee Valley and Mid-Atlantic region where it will remain a focus for showers and thunderstorms. An upper level high is forecast to remain centered over the southern Rockies and southern High Plains region over the next few days, with some tendency for the ridge axis to build slowly off to the west which will encompass more of the Southwest. This will advect enhanced levels of monsoonal moisture from northwest Mexico into the Desert Southwest and the Great Basin. Weak upper level disturbances embedded in the flow around the upper high coupled with the monsoonal moisture plume will enhance shower and thunderstorm activity across these areas over the next couple of days with locally heavy rains and some concerns for flash flooding. The potential for wet weather across these areas will also keep temperatures below average. This will especially be the case on Wednesday as high temperatures are forecast to be as much as 10 to 20 degrees cooler than average across much of Arizona, Utah, southeast Nevada and far southeastern California. Meanwhile, as showers and thunderstorms around the western periphery of the upper high over the Four Corners region will act to keep temperatures cooler, the temperatures will actually be above average farther east out across the central and southern High Plains where temperatures will likely exceed 100 degrees over the next few days. Elsewhere, a weak Pacific front stalled out across the Northwest may help to trigger some widely scattered showers and thunderstorms, with a focus generally on the northern Rockies, but otherwise the Northwest will be dry at least for a couple more days with temperatures as much as 5 to 10 degrees above normal. Orrison Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php