Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 227 AM EST Mon Feb 12 2018 Valid 12Z Mon Feb 12 2018 - 12Z Wed Feb 14 2018 ...Warming trend for much of the nation through Wednesday... ...Heavy snow for the San Juan mountains in southern Colorado today... The upper pattern will feature a series of upper level disturbances and general upper level troughing over the western half of the nation through mid-week. An upper level disturbance sinking south through the Great Basin and California today will coincide with an increase in moisture and precipitation across the Southwest into the Four Corners region today with higher elevation snow forecast across northern Arizona, Utah and Colorado. Snowfall will be locally heavy across the Colorado Rockies, with favored locations within the San Juan Mountains in particular, expected to receive over a foot of new snow by Tuesday morning. Retrogression of the upper disturbance near California will allow precipitation to dwindle across the Southwest for Tuesday. A second upper level disturbance is on track to impact the northwestern U.S. starting Tuesday night as a cold front sweeps across the area. The quick moving nature of the system and a lack of better moisture should keep rain/snowfall totals on the light side. Out east, light to locally moderate rain will continue across the Mid-Atlantic coast and Southeast U.S. today as a cold front continues to move off into the western Atlantic. High pressure will slide eastward as the front moves south into Florida through Tuesday, allowing for mostly dry weather for the majority of the eastern half of the country today into Tuesday. Showers are expected to increase during the day on Tuesday from eastern Texas into the lower Mississippi valley as moisture and warmer air moves northward from the Gulf of Mexico across the western end of a lingering frontal boundary in the Gulf. Rainfall coverage and intensity will expand north and east into the Ohio Valley and Appalachians for Wednesday. As high pressure moves into the western Atlantic late Tuesday into Wednesday, return flow around the west side of the high will allow warmer temperatures to spread north into locations east of the Continental Divide. This will allow for some rather dramatic temperature changes for the Plains compared to today. By Wednesday, highs across Oklahoma and Kansas are expected to reach into the 60s and lower 70s. Lingering snow cover to the north, from Nebraska, Iowa and northern Illinois/Indiana northward, should keep high temperatures lower than what they would otherwise be. Still, Wednesday's maximum temperatures should still rise 10 to 20 degrees above average for the north-central U.S. and modestly above average for the remainder of the lower 48, except along the West Coast where temperatures should stay near average. Otto Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php