Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 300 PM EST Tue Dec 12 2017 Valid 00Z Wed Dec 13 2017 - 00Z Fri Dec 15 2017 ...Improving but still elevated fire weather conditions for Southern California... ...Coastal storm to bring wintry conditions to portions of the Northeast today and tonight... ...Locally heavy lake effect snowfall to continue downwind of the Great Lakes... The warm and dry conditions across the West will persist through midweek, however the threat for critical fire weather will lessen as the upper ridge begins to weaken. Light precipitation will be possible along and east of the Northern/Central Rockies as a series of clipper systems dive southeast from Canada. In advance of the first clipper, downslope winds will generate high temperatures across the central and northern High Plains in the 50s and 60s, well above average for mid-December. Colder temperatures will reside farther north and east in this pattern with the clipper systems generating light snow or a wintry mix across the eastern Dakotas into Minnesota but with any accumulations generally below an inch. Rain will move into the coastal areas of the Pacific Northwest by Thursday afternoon as a cold front over the Pacific Ocean approaches the coast. Widespread rain and snow is moving across the Northeast today in associations with a passing cold front. Much colder air will spill into the East Coast; which will result in maximum temperatures ranging 10 to 20 degrees below average from Florida to the Great Lakes on Wednesday. Meanwhile, as the low pressure center continues to wrap up tonight into Wednesday morning over New England, moderate snowfall is expected for portions of upstate New York into interior portions of New England with a wintry mix possible from central Massachusetts to the coast of Maine. Winter Storm Warnings and Winter Weather Advisories are in effect for these locations through Wednesday morning given the anticipated deteriorating conditions. Additionally, prime conditions for lake enhanced snowfall will continue through Thursday (cold air blowing across the relatively warm Great Lakes). The greatest accumulations across southwestern Lower Michigan and east of lakes Erie and Ontario where local totals over a foot will be possible. Lake Effect Snow Warnings are in effect for northeast Ohio,northwest Pennsylvania and southwest New York. Campbell/Otto Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php