Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 249 PM EDT Sun Jun 27 2021 Valid 00Z Mon Jun 28 2021 - 00Z Wed Jun 30 2021 ...The Historic Heat Wave to continue across the Northwest. Some relief for areas to the west of the Cascades by Tuesday... ...Additional Heavy rains likely from the Southern High Plains into the Middle Mississippi Valley, leading to a continued flood and flash flood threat across these areas... ...Much above average temperatures likely for the Northeast early this week, while much below average temperatures expected across much of the Central and Southern Plains... ...Tropical weather threat for the Southeast Coast Monday into Tuesday... The large scale weather pattern across the nation is not expected to change appreciably over the next few days, maintaining anomalous weather conditions across many areas. The historic Northwest Heat Wave will continue through much of the upcoming week, with numerous daily, monthly and even all time records likely to be set. Monday will be the hottest day for the big cities of Seattle and Portland with all time record highs likely in both cities. For both Seattle and Portland the forecast highs Sunday and Monday will be back to back all time highs, with the new all time highs of Sunday being broken the next day. Some relief is possible from the record heat for Seattle and Portland on Tuesday as the core of the hottest air pushes inland to the east of the Cascades. Still, high temperatures Tuesday will be 15 to 20 degrees above average and morning lows will be near the average afternoon highs for both Seattle and Portland. No relief in sight for this week for areas to the east of the Cascades across eastern Oregon, eastern Washington State, much of Idaho into western Montana where daily highs will be 25 to 30 degrees above average and daily records are likely. Excessive Heat Warnings are currently in effect across all of the Northwest, southward into northern California, western Nevada and portions of Southern California. In addition to the life-threatening aspects of the historic heat wave across the Northwest, the hot/dry conditions will also pose a fire weather threat for much of the upcoming week. The overall stagnant weather pattern across the nation will keep a frontal boundary stationary from the Southern Plains, northeastward into the Middle Mississippi Valley. This front will be the focus for additional heavy rains over the next days, with flood and flash flood watches currently in effect across these areas. Stream flows have become elevated from heavy rains over the past 24 hours across these areas, with the threat of more heavy rains into the start of this week continuing the flood and flash flood threat. The heavy rain threat will also keep temperatures well below average over the next few days, especially across the Central to Southern High Plains. Across this region, high temperatures are forecast to be 15 to 20 degrees below average with even the chance of record low maximum temperatures Monday and Tuesday across New Mexico into northwest Texas. Across the eastern U.S....much above average temperatures will also be in store for early this week from the Ohio Valley into the Mid-Atlantic and New England. While temperature anomalies are not expected to be as great as the Northwest, a few record highs are possible in the urban corridor from Boston to New York City. Off the Southeast Coast, an area of disturbed tropical weather is currently moving westward toward the coast. The National Hurricane Center is investigating this system for potential tropical development. Please see the latest outlooks and/or advisories from the National Hurricane Center for further details of potential impacts to the Southeast coast Monday and Tuesday. Oravec Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php