Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 359 AM EDT Wed Oct 26 2016 Valid 12Z Wed Oct 26 2016 - 12Z Fri Oct 28 2016 ...A persistent upper trough will keep conditions wet along the West Coast... ...Light to moderate snow possible over interior sections of New England... ...Well above normal temperatures expected across the center of the nation... The overall pattern through the end of the work week will be active, particularly across the western United States where moderate to heavy rainfall is likely. A complex array of systems over the eastern Pacific will collectively keep conditions wet along the entire West Coast. Initially, the action should be confined to northwestern California up along the Pacific Northwest coast into Vancouver Island. Continued onshore flow coupled with energetics with each disturbance passage will spread abundant rainfall across the northwestern states with the highest amounts over orographically favored locations. This includes the Siskiyou Ranges up into the Olympics and Cascades where 2 to 4 inches of precipitation is likely through Thursday morning. As time proceeds forward, a second major system swings toward the Southern/Central California coast by midday Thursday. This will spread well needed rainfall from the San Francisco Bay Area southward down into Los Angeles and San Diego. And of course western slopes of the Sierra Nevada Range can expect abundant rainfall with lighter amounts further downstream given downsloping effects. Wintry precipitation does not appear to be a big issue given the warm nature of the weather pattern. An upper trough migrating through the Middle Mississippi Valley is currently dropping locally heavy rainfall to areas of the Upper Midwest/Upper Great Lakes. This is generally occurring near the parent surface cyclone and just north of the west-east oriented frontal zone. Given the current forecast track of these features, expect the most organized rainfall from southern Wisconsin/northern Illinois eastward across the Lower Great Lakes into much of New England. A marginal flash flood risk accompanies this broad region, particularly around the Minnesota/Wisconsin/Iowa border. Meanwhile, there should be enough cold air present at some of the higher elevations of interior New England to support light to moderate accumulations of snow. At this point, the highest accumulations are expected to be over the Adirondacks where 4 to 8 inches are expected. Generally speaking, the pattern for the rest of the work week will feature well above normal temperatures. The exception to this rule is over the Great Lakes and northeastern U.S. where the threat of rainfall and enhanced cloud cover will keep readings below normal. Before this upper trough arrives into the Mid-Atlantic/New England region, a strong surface ridge has brought near to below freezing temperatures to much of the area this morning. Looking to the warmth across the center of the country, a building ridge will favor very mild temperatures for late October. In fact, by Thursday, expect the mercury to reach the 80 degree Fahrenheit mark as far north as southern South Dakota. The largest departures from normal are expected over the Central/Northern High Plains with readings possibly 15 to 25 degrees above climatology. Rubin-Oster Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php