Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 306 PM EDT Fri May 12 2023 Valid 00Z Sat May 13 2023 - 00Z Mon May 15 2023 ...Heavy rain, flash flooding and severe weather likely across large portions of the Plains... ...Much above average to record heat building across the Pacific Northwest, while below average temperatures expected across large portions of the Plains... An active and wet weather pattern setting up for the mid section of the nation this Mother's Day weekend. Two strong, well defined upper level lows will focus heavy rainfall, flash flooding and severe thunderstorms threats across large portions of the mid section of the nation. Initially, the heaviest precipitation is expected to focus ahead of the strong closed low over the Central Plains, which will be lifting slowly northward Friday night into Saturday toward the Northern Plains. This will bring heavy rain potential and isolated flash flooding from eastern Montana, across much of the Dakotas, northern Nebraska, Iowa and southern Minnesota. Severe thunderstorms also possible across these areas, especially from eastern Nebraska, southeast South Dakota, across Iowa and into northwestern Illinois. Across these regions high winds, large hail and tornadoes are possible. Farther to the south, another well defined upper level closed low will be forming across northeast Mexico and lifting northward into southwest to western Texas/eastern New Mexico from Friday night into Sunday. Widespread heavy rains are likely across much of Texas, Oklahoma, southwest Arkansas, northeast New Mexico into southeast Colorado. Flash flood watches are currently in effect across large portions of the Southern Plains. While bringing potential for flash flooding, the expected heavy rains will also bring relief to the severe to extreme/exceptional drought conditions currently affecting large portions of the Southern Plains. In addition to the heavy rain and flash flooding threat, severe thunderstorms also possible across large portions of the Southern Plains where large hail and high winds will be the greatest threat. In the areas of heavy rainfall potential, temperatures will be below average over the next few days given limited sunshine potential, with high temperatures running 10 to 20 degrees below average. In contrast to the below average temperatures, heat will continue to build from the Desert Southwest, through California and into the Pacific Northwest where an upper level ridge will be strengthening. High temperatures across these regions expected to be from 10 to 25 degrees above average this weekend. Some of the largest high temperature anomalies are expected over the western portions of Oregon and Washington State where both record high afternoon temperatures and record high morning low temperatures are possible through the weekend. Heat advisories are in effect for this early season heat wave through the weekend across areas to the west of the Washington and Oregon Cascades. Above average temperatures also likely across areas from the Mississippi River, eastward through much of the eastern U.S. While afternoon highs are expected to be as great as 10 to 15 degrees above average, no record high temperatures are expected from the Mississippi River eastward to the east coast. There is, however, potential for near record to record high minimum temperatures in the urban corridor from Boston to Washington D.C. Saturday morning. Oravec Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php