Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 349 PM EDT Sat Jul 28 2018 Valid 00Z Sun Jul 29 2018 - 00Z Tue Jul 31 2018 ...Severe thunderstorms and flash flooding possible across portions of the central Plains through Sunday... ...Dangerous heat to continue across the Southwest and California through Sunday, moving into the Pacific Northwest to start the work week... ...Lingering showers and thunderstorms near coastal regions along the Gulf of Mexico and Atlantic Seaboard through the rest of the weekend... A series of upper level disturbances rounding the top of a stubborn ridge across the Southwest will interact with a frontal boundary draped from the central High Plains to the lower Mississippi Valley. This will result in numerous showers and thunderstorms from the Rockies to the central Plains and into the middle/lower Mississippi Valley this weekend. A moist and unstable airmass in place will allow for an environment favorable for both severe weather and heavy to excessive rainfall/flash flooding, with the greatest chance along the frontal boundary in the High Plains. The Storm Prediction Center has highlighted a region from southeast Wyoming to central Kansas within an enhanced risk for severe thunderstorms this afternoon and overnight. A slight risk of severe thunderstorms will linger in this region through Sunday. A developing low pressure system will also result in a slight risk of severe thunderstorms over northern Arkansas and south-central Missouri on Sunday as well. The Weather Prediction Center also has outlined a slight risk of exceeding flash flood guidance for the rest of the weekend and into Monday across portions of the central Plains. Please refer to the outlooks by these centers for additional information. The relentless heat across the Southwest and parts of California will continue through the remainder of the weekend. Numerous excessive heat warnings and advisories remain in effect through Sunday evening. The upper ridge responsible for the dangerous, multi-day, heat wave will also begin building up the west coast through the last half of the weekend. Afternoon high temperatures by the end of the weekend across the Pacific Northwest could be anywhere from 5 to 15 degrees above normal, and excessive heat watches are in effect for some locations as afternoon highs are forecast to soar to near or just above 100 degrees for Monday and Tuesday. Due to continued hot and dry conditions, fire weather and poor air quality will also remain a concern across much of the Western states. Meanwhile, a lingering front across the Southeast and eastern seaboard will keep showers and storms in the forecast for the weekend, mainly along coastal regions. Much of the activity should be relatively light and scattered in nature, but the best chance for heavy rainfall will be along the stalled boundary in the eastern Carolinas as well as across Florida. Showers and thunderstorms currently ongoing across the Northeast will taper off by Sunday as this portion of the front continues to slowly push eastward into the Atlantic Ocean. Santorelli/Wix Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php