Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 400 AM EDT Tue May 30 2023 Valid 12Z Tue May 30 2023 - 12Z Thu Jun 01 2023 ...Widespread scattered showers and thunderstorms continue across large portions of the central U.S., the northern Rockies and northern Great Basin... ...Showery conditions spreading farther south into the southern Mid-Atlantic today followed by increasing chance of thunderstorms across southern Florida on Wednesday... ...Much above average temperatures expected along the northern tier of the nation, while cooler than normal conditions accompany the showers across the Southeast... The large-scale flow pattern across the mainland U.S. remains fairly blocked over the next few days, characterized by a mean trough across the western half of the country, together with another trough from the southern Mid-Atlantic into the Southeast, while a closed upper high expands across the Great Lakes into the Northeast. The prevailing mean trough across the western U.S. will continue to support widespread scattered showers and over the next two days from northern California through the northern Great Basin, Northern Rockies and across much of the Plains states. Across these regions, isolated heavy rainfall amounts are possible along with isolated instances of flash flooding. Meanwhile, sustained moist low-level flow up the Great Plains will continue to interact with impulses coming off the Rockies from the mean trough to produce clusters of strong to severe thunderstorms. The highest chance for these storms to be severe is forecast to be over the central High Plains for the next couple of days. Across the Mid-Atlantic, a slow-moving upper low will inch its way offshore today as a back-door front continues to push cooler air from New England down the East Coast and the Appalachians. Scattered showers and embedded thunderstorms should gradually taper off today across the Mid-Atlantic coast as a high pressure ridge brings cooler and more stable air into the region. Meanwhile, the scattered showers and storms will move farther south into the Carolinas with the passage of the back door front, reaching into the Southeast and farther up across the Midwest on Wednesday into early Thursday. Meanwhile, another upper trough is currently drifting off the Texas coast into the western part of the Gulf of Mexico. This upper trough could spawn a new low pressure system in the Gulf of Mexico the next couple of days as it heads generally east toward Florida. The chance of showers and thunderstorms will begin to increase today across southern Florida. By Wednesday night into early Thursday, the showers and thunderstorms should become more numerous across South Florida and may become heavy at some locations A closed upper high will remain parked across the northeastern portion of the nation from the Great Lakes into New England. Dry conditions and much above average temperatures will accompany this upper high with high temperatures 15 to 20 degrees above average across much of the northern tier from the northern Plains, through the upper Great Lakes, northern New York State into northern New England. In contrast, cooler than average temperatures over the next few days will be associated with the showery pattern across the southeastern U.S. and along the West coast into the Desert Southwest. Kong/Oravec Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php