Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 224 PM EST Thu Jan 09 2014 Valid 00Z Fri Jan 10 2014 - 00Z Sun Jan 12 2014 ...The East will be increasingly wet and milder while the Pacific Northwest will see lower elevation rains/higher elevation snows... ...Bouts of windy conditions anticipated across the higher elevations of, and east of, the Colorado Rockies Friday into this weekend... A portion of the polar vortex has strengthened in response to a strong cyclone which originated across the Midwest on Sunday, strengthening as it moved northward across eastern Canada. The various elements of the vortex congeal across Nunavut over the next couple of days which in turn strengthens the Westerlies across the lower 48 United States and leads to greater west-to-east system progression and milder conditions across the Plains and East than seen over the past week. Atlantic moisture moves up a developing coastal front due to a weak disturbance aloft, from Florida up the coast of the Carolinas, helping to lead to an increasingly cloudy/moist pattern across the East with time. Some snows are possible along the system's northern periphery across the upper Midwest, Great Lakes, New York, and New England from late today into Friday afternoon, with some freezing rain possible Friday morning across portions of the Mid-Atlantic states as the last of the arctic air mass erodes away, which helps to melt the residual snow pack across the region. The second and stronger progressive system moves out of the West into the southern/central Plains by Friday morning, dragging snows through the central Rockies and luring Gulf moisture into the southern Plains/Mid-South. Thunderstorms break out within the increasingly unstable air mass from the southern Plains into the Mississippi valley and Southeast, with thunder-freezing rain possible across portions of Iowa and Wisconsin late Friday. As a surface low strengthens while moving from the southern Plains into the Great Lakes, a comma head-pattern of snowfall is expected from the upper Mississippi valley across the upper Great lakes late Friday. A third system approaches the Pacific Northwest Saturday into Sunday, spreading higher elevation snows and lower elevation rains, with the heaviest rainfall expected Saturday night into Sunday morning across portions of coastal Washington and Oregon. As these various systems cross Colorado during the next few days, fits of wind are expected through this weekend. Strong Bora winds -- a colder regional downslope/Foehn wind -- are anticipated above the timberline and in the lee of the Colorado front range on Friday. See area forecast discussions from the Denver/Boulder office for more on the windy and changeable weather conditions expected in their area. Roth Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php