097 FXUS01 KWBC 280556 PMDSPD Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 155 AM EDT Thu May 28 2026 Valid 12Z Thu May 28 2026 - 12Z Sat May 30 2026 ...Widespread showers and thunderstorms to persist across the Southern U.S. through the end of the week... ...An Pacific low maintains unsettled conditions and isolated severe weather across the Northwest... ...Summerlike heat continues over the northern tier while unseasonably cool conditions linger out West... A very warm, humid, and unstable air mass situated south of a meandering frontal boundary across the southern United States will continue to support widespread showers and thunderstorms over the next few days. Persistent shortwave disturbances tracking along this boundary will sustain a wet convective pattern extending from the Southern Plains eastward into the Southeast and Mid-Atlantic. While the more extensive flash flood threats from previous days have begun to subside, a Marginal Risk of Excessive Rainfall (level 1/4) remains in place today from eastern Texas through the central Gulf Coast, where soils remain heavily saturated from antecedent precipitation. By Friday and into the weekend, the focus of the heaviest rainfall is expected to shift farther southward toward the immediate Gulf Coast and Southeast, though the threat of at least isolated instances of flash flooding will persist. Across the Western U.S., a deep Pacific upper-level low remains entrenched over California and the Great Basin while making slow eastward progress. Favorable large-scale ascent and a concomitant influx of moisture associated with this system will maintain numerous showers and thunderstorms broadly from central and northern California into the Pacific Northwest and northern Rockies today, before centering over the Great Basin by Friday. Higher elevations of the Sierra Nevada will continue to see wet mountain snow. Concurrently, a potent mid-level shortwave tracking around the northern periphery of the upper low will emerge across the Northwest this afternoon. Robust surface heating and an increase in low-level moisture will drive significant instability across the Columbia Basin, allowing thunderstorms to commence by mid-afternoon. Most short-term convective guidance indicates upscale growth into linear segments, supporting a primary threat of damaging wind gusts along with isolated large hail. Consequently, the Storm Prediction Center has outlined a Slight Risk (level 2/5) of severe thunderstorms for portions of the Columbia Basin, encompassing northern Oregon and south-central Washington. Elsewhere, an upper-level low dropping southward from southeastern Canada will generate a surface low-pressure system and an associated cold front across New England late Thursday and into Friday. This system will bring a round of showers and thunderstorms to the region, with the potential for locally heavy rainfall across central New England into southern Maine. In terms of temperatures, a stark thermal contrast will remain in place across the Lower 48 this week. Hot, summerlike heat will persist across the northern Rockies, northern Plains, and Upper Midwest due to the influence of an Omega blocking pattern. Daytime highs soaring into the 80s and 90s will range from 25 to 35 degrees above seasonal averages. Some locations across eastern Montana and western North Dakota may approach 100 degrees. In sharp contrast, temperatures will remain well below average under the influence of the deep upper-level low out West, with highs generally confined to the 50s and 60s outside of the Desert Southwest. Near-seasonal temperatures in the 70s and 80s will prevail farther east from the south-central U.S. to the East Coast. Blanco-Alcala Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php $$