Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 250 PM EST Fri Feb 21 2020 Valid 00Z Sat Feb 22 2020 - 00Z Mon Feb 24 2020 ...Cold temperatures across the eastern two-thirds of the country will gradually moderate this weekend... ...A Pacific storm system to impact the Southwest on Saturday, Central Rockies/Plains on Sunday... ...Rain and mountain snow return to the Northwest on Sunday ... The Lower 48 will continue to observe tranquil weather conditions through this evening as a large dome of high pressure remains in control. Chilly temperatures will be felt across the eastern half of the country tonight and Saturday morning with the coldest anomalies located in the Southeast. A few Freeze Warnings have been issued for parts of the Lower Mississippi Valley and the Southeast early Saturday morning. As high pressure slides eastward throughout the weekend, winds will shift out of the south and southwest over the Nation's Heartland, Great Lakes, and Northeast leading to the return of milder temperatures. The first in a pair of Pacific storm systems to impact the U.S. arrives late tonight in the Southwest as a low pressure system approaches the region. This storm system will tap into a source of deep moisture originating from the subtropical Pacific and send said moisture into the Southwest on Saturday. In response, rain will develop across the Southwest with thunderstorms also possible in portions of southern Arizona and New Mexico. The heaviest rainfall looks to be concentrated in the higher elevations of western New Mexico and south-central Arizona where rainfall totals ranging between 1 and 2 inches is possible. A Slight Risk for Excessive Rainfall has been issued for these areas due to heavy rainfall rates potentially causing areas of flash flooding on Saturday. By Sunday, this storm system will intensify in the Central Plains generating areas of showers and a few thunderstorms. Look for mountain snow to fall from the southern Sierra Nevada and the Wasatch to the Colorado Rockies this weekend as well. Further north, a separate Pacific storm system will cause an increase in showers and and mountain snow over the Pacific Northwest on Sunday. The Olympics and Cascades will receive more mountain snow while the valleys and coastal areas see rain. The storm system will then track into the northern Rockies Sunday night leading to more areas of mountain snow through Monday morning. Mullinax Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php