Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 234 PM EST Fri Jan 05 2018 Valid 00Z Sat Jan 06 2018 - 00Z Mon Jan 08 2018 ...An Arctic outbreak will keep temperatures 20 to 30 degrees below average across the northeastern U.S... ...Wet conditions expected from northern California into the Pacific Northwest... ...A threat for accumulating ice is likely over interior Washington/Oregon... Frigid air in place over much of the Northeast and Mid-Atlantic will keep temperatures well-below normal this weekend. Locations across the Northeast have forecast temperatures that will average 20 to 30 degrees those normal for early January - with a plethora of locations struggling to get above the single digits and may result in daily records to be broken. Brisk winds across the region combined with this Arctic airmass with create dangerously cold conditions. Wind Chill Warnings and Advisories are in effect from Maine to North Carolina. Frigid temperatures also extend down into the southern U.S. as lows plunge into the 20s down along the eastern Gulf Coast and into central Florida. Many daily records may be broken across this sector of the country as well. Extremely cold temperatures aloft moving over many unfrozen lake surfaces will foster the development of widespread snow showers over all the major Great Lakes. The heaviest snow is expected to be southeast of Lake Ontario which would affect areas anywhere from Rochester to Syracuse, New York. Onshore flow combined with Pacific systems approaching the Northwest will keep much of Washington to northern California and east toward the Northern and Central Rockies in a wet pattern. Coastal rains and higher elevation snows will continue through the weekend. A broad area of 1 to 2 inches of precipitation is forecast for the Washington Cascades. During the next couple of days, many mountain ranges over the western U.S. should see accumulating snows with the highest amounts likely over the Colorado Rockies with the potential for over a foot. Meanwhile, maritime flow overriding a sub-freezing surface layer should make conditions favorable for freezing rain across sections of central/eastern Washington down into eastern Oregon. A warming trend is expected from the Four Corners region northward to the High Plains. Downsloping flow is forecast to bring well above normal temperatures for these locations into the weekend. By Saturday, expect highs to reach the upper 40s up into the Black Hills which would be around 15 to 20 degrees above climatology. Much of the central U.S. may be impacted Sunday into Monday by freezing rain as a low pressure system develops over the Southern Plains and lifts warm Gulf air into the area with arctic air. The swath of freezing rain is most likely to span from eastern Kansas to the Ohio Valley, possibly south toward the Atlanta area. If this materializes, widespread disruption to trans portion may occur. Campbell/Rubin-Oster Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php