Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 258 AM EST Sat Dec 02 2017 Valid 12Z Sat Dec 02 2017 - 12Z Mon Dec 04 2017 ...Heavy snow possible over parts of the Northern Rockies... A developing upper-level low just off the Northwest Coast will move eastward to the Northern Intermountain Region/Northern Rockies by Sunday evening. The system will produce rain and higher elevation snow over parts of the Pacific Northwest and snow over parts of the Northern Intermountain Region that will move inland on Saturday to parts of Northern California by Saturday evening. Snow will continue to move inland to the Northern Rockies/Great Basin on Sunday into Sunday evening. The rain and higher elevation snow will begin to wind down also on Sunday into Sunday evening over the Pacific Northwest and Northern California. Meanwhile, upper-level energy over the Upper Great Lakes will aid in producing light rain over the region on Saturday morning into evening. In addition, upper-level energy moving off the Southeast Coast will aid in producing light rain over parts of the Southeast/Southern Mid-Atlantic on Saturday morning ending overnight Saturday. Elsewhere, upper-level energy over Northwestern Mexico will move eastward to the Southern Plains on Sunday into Sunday evening. Moisture from the Gulf of Mexico will begin to stream northward over the Southern Plains on Saturday that will intensify overnight Saturday into Sunday. The moisture and energy will aid in developing shower and thunderstorms over parts of the Southern Plains/Western Gulf Coast Sunday morning into Sunday evening. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php