Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 251 AM EST Mon Jan 05 2015 Valid 12Z Mon Jan 05 2015 - 12Z Wed Jan 07 2015 ...Heavy rain possible over parts of the Cascades... ...Snow possible over parts of the Middle Mississippi Valley to the Ohio Valley and the Northern Rockies/High Plains... ...Temperatures will be 15 to 25 degrees below average from the Northern Plains to the Upper Great Lakes/Western Ohio Valley... Strong onshore flow over the Pacific Northwest will slowly wane on Monday. In the meantime, light to moderate rain will develop along the Pacific Northwest and into parts of the Northern Intermountain Region through Monday evening. Moderate snow will develop over parts of Northern/Central Rockies on Monday. Cold high pressure over the Middle Mississippi Valley will move eastward to the Ohio Valley and modify by Monday evening. A second cold high pressure area over West-Central Canada will move into parts of the Northern High Plains on Tuesday. Circulation around the high pressure will aid in producing upslope flow that will produce snow over the Northern High Plains to parts of the Central Plains on Tuesday. Meanwhile, a clipper system will develop over the Central Plains on Monday afternoon and move eastward to off the Mid-Atlantic Coast by Tuesday evening. The system will produce light to moderate snow over parts of the Central Plains/Middle Mississippi Valley on Monday afternoon/evening that will move eastward into the Ohio Valley/Northern Mid-Atlantic by Tuesday morning. Upper-level energy moving over the Great Lakes along with cold air will aid in producing lake effect/lake enhanced snow downwind from the Great Lakes through Tuesday evening. Elsewhere, a lingering front over Southern Florida will aid in producing light rain over the area through Tuesday. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php