Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 355 AM EDT Thu May 28 2020 Valid 12Z Thu May 28 2020 - 12Z Sat May 30 2020 ...Moisture associated with Bertha could cause additionally locally heavy rain and flash flooding today in portions of the Carolinas and southern Virginia... ...Thunderstorms expected in the eastern half of the U.S., causing heavy rain in the Midwest today and severe weather in the Mid-Atlantic/Northeast Friday... ...Record-breaking heat continues in the West... Though Bertha is becoming post-tropical, its low pressure system is expected to track northward across the Appalachians today, spreading tropical moisture across the Eastern Seaboard. Rain and thunderstorms should continue today over portions of the Southeast and Mid-Atlantic. As some of these areas have already received copious amounts of rainfall over the last several days, flooding and flash flooding could be a threat, especially over portions of the eastern Carolinas and Virginia, where there is a Slight Risk of exessive rainfall in place today. Bertha is expected to dissipate by tonight. Scattered showers and thunderstorms are forecast once again today across the central and eastern U.S. underneath a persistent upper-level low. Strong to severe thunderstorms are most likely over parts of southern Texas and the central Gulf states, where Slight Risks of severe weather have been outlined by the Storm Prediction Center. This upper low will finally lift north and combine with the main jet stream on Friday. At the surface, a cold front is forecast to move across the Midwest today and provide a focus for rain and thunderstorms; along and ahead of the front, a Slight Risk of excessive rainfall/flash flooding is in place from the Middle Mississippi Valley into the Upper Great Lakes. Then on Friday as the front moves into the Northeast and Mid-Atlantic, severe weather is a threat for those regions as organized convection could form. Locally heavy rainfall and isolated flooding are also possible there. Behind the cold front, the central U.S. should finally dry out Friday into Saturday. Heat will be persistent in the West, with high temperatures 15 to 25 degrees above average across California, the Great Basin, and the Southwest over the next couple of days. Daily record temperatures should be set in these areas as temperatures exceed 100 degrees in many places. Heat Advisories and Excessive Heat Warnings are widespread across California and the Southwest. The West Coast should start to cool down by Saturday as a potent upper-level low approaches, but hot temperatures will remain over interior parts of the West. Farther east, the greatest temperature anomalies are expected today across Maine, where temperatures nearing 90 are unusual. Slightly cooler than average temperatures are forecast across the center of the country behind the cold front. Tate Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php