Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 321 PM EDT Mon May 31 2021 Valid 00Z Tue Jun 01 2021 - 00Z Thu Jun 03 2021 ...Warming trend and excessive heat across the western United States... ...Heavy rain and flash flooding are likely into early Tuesday morning across portions of central and northern Texas... ...Severe weather will remain possible across the southern High Plains into mid-week... ...Showers and thunderstorms to slowly spread eastward into the Lower/Middle Mississippi and Ohio Valleys through Wednesday... The upper level pattern across the lower 48 will feature ridging over the western U.S. while troughing slowly edges east atop the Great Plains and Mississippi River Valley. The upper pattern will dictate the weather at the surface, with the western ridging supporting hot and dry weather for locations west of the Continental Divide. High temperatures will display a warming trend through Wednesday for the western third of the nation as the upper ridge slowly moves east. Excessive Heat Watches/Warnings and Heat Advisories are already in place across portions of Washington, Oregon, California and southern Nevada. High temperatures will be well into the 90s to over 100 degrees on Tuesday and Wednesday for many out West, with the greatest departures from average high temperatures (20 to 30 degrees above climatology) occurring in the Northwest where quite a few record highs are forecast on Wednesday. Across the Southern Plains, conditions will remain unsettled in the vicinity of a slow moving surface low and associated front that is forecast to slowly move east into the middle of the week. Above average moisture and weak upper level impulses will help to support areas of locally strong to severe thunderstorms along with flash flooding from portions of central and northern Texas into southern Oklahoma through Tuesday morning. An additional 1 to 3 inches of rain is expected through Tuesday morning across portions of Texas, but locally higher totals are likely. During the day on Tuesday and Wednesday, showers and thunderstorms will track eastward into the Lower/Middle Mississippi and Ohio Valleys, bringing both the possibility of severe weather and flash flooding. Through Wednesday, threats for severe thunderstorms will remain each day from southwestern Texas into eastern New Mexico where sufficient wind shear and daytime heating will allow for an increase in the coverage of severe storms with elevated chances for large hail and damaging winds. Clouds and rain will help to keep temperatures over most of the central to south-central U.S. below average through Wednesday. For the eastern third of the nation, high pressure will support mostly pleasant weather and near average temperatures with thunderstorm chances limited to the coast of the Southeast and Florida through Tuesday near a weakening frontal boundary. Rain chances are expected to increase from west to east ahead of the system approaching from the central U.S. on Wednesday. Otto Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php