Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 400 PM EDT Sat Jun 24 2017 Valid 00Z Sun Jun 25 2017 - 00Z Tue Jun 27 2017 ...A cool weather pattern is in store for much of the eastern two-thirds of the country... ...Record heat continues for the Pacific Northwest... ...Heat becomes less extreme in the Desert Southwest... The synoptic weather pattern across the U.S. mainland will feature a broad upper-level trough in the East while an upper-level ridge will persist for a couple more days in the West. This means that much of the eastern two-thirds of the country will be cooler than normal throughout the weekend while heat will persist in the western U.S. A high pressure ridge, reminiscence of a cold season arctic outbreak, is forecast to gradually build across the northern and central Plains and then eastward into the mid-Atlantic for the next few days. This will keep high temperatures only into the 60's and 70's in the northern/central Plains and 70's to 80's across the mid-Atlantic with plenty of sunshine, making for very pleasant conditions in these areas for late June! Around the Great Lakes into northern New England however, a stationary front combined with periodic passages of upper-level disturbances will lead to scattered showers and some thunderstorms to linger into Monday. Meanwhile, the leading edge of the cool air mass will become nearly stationary from the southeast U.S. coast down along the Gulf Coast and westward into the southern Rockies for the next few days. This will keep scattered showers and thunderstorms around the area into Monday. Thunderstorms should be somewhat more numerous from New Mexico into western Texas. Along the West Coast, high pressure ridge aloft will continue to keep temperatures well above normal with dry conditions through the weekend. The most anomalous temperatures will be across the Pacific Northwest where highs are forecast to exceed 100 degrees at some interior locations today and Sunday. These temperatures are 15 to 25 degrees above average. By Monday, a cold front from the eastern Pacific is forecast to move onshore, bringing a good chance of thunderstorms across the Intermountain region into the northern Rockies and cooler temperatures along the Pacific Northwest coast. Meanwhile, heat will continue in the Desert Southwest through the weekend, albeit not as extreme as in previous days. Nevertheless, high temperatures are still expected to reach 120 degrees near the typically hottest locations. Kong Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php