Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 356 PM EST Thu Nov 14 2013 Valid 00Z Fri Nov 15 2013 - 00Z Sun Nov 17 2013 ...Heavy snow likely over the Western U.S... ...Mild temperatures return for the weekend across the East Coast... The upper pattern across the nation for the middle of the November will feature an expansive trof nearly extending from coast to coast. Initially, very little precipitation is expected across the Continental U.S. early in the period given the scant moisture content available. The weather will become much more active by Friday afternoon onward over much of the Western U.S. in response to a strengthening upper trof from British Columbia. As this system noses southward, Pacific moisture is forecast to ramp up with upslope precipitation commencing across much of the northwestern states. Snow levels will gradually begin to drop as cold air surges southward from western Canada. This should eventually bring wintry precipitation to some of the valley locales of the Intermountain West. The latest WPC winter weather desk forecast suggests the heaviest snowfall amounts over the Washington/Oregon Cascades and Bitterroots where roughly 12 to 18 inches of snow will be possible through Saturday afternoon. Elsewhere, amounts closer to 6 to 12 inches are expected over the Tetons, Wasatch, and Colorado Rockies. An arctic frontal zone which sunk well into the southern extent of the Gulf of Mexico is forecast to rise back toward the north as a warm front. This will ultimately advect a moisture rich air mass back toward the Gulf coast which will increase the threat for showers and thunderstorms. At this point, the heaviest rainfall amounts are expected to straddle the coast although this activity could remain just offshore. Regardless, milder temperatures combined with a threat for showers and thunderstorms will be the norm for the Central/Eastern Gulf Coast from Friday morning into Saturday. After a bout with well below normal temperatures the past couple of days, the eastern third of the country will gradually begin to rebound. This is in response to a surface ridge which will shift eastward into the coastal Atlantic. The clockwise flow around the anticyclone will allow the flow to come more out of the Gulf of Mexico which should moderate temperatures. This should bring readings closer to normal or just above climatology. Rubin-Oster Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php