Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 424 PM EDT Thu Oct 19 2017 Valid 00Z Fri Oct 20 2017 - 00Z Sun Oct 22 2017 ...Heavy snow for the Northern Cascades... ...Snow for parts of the Cascades and Northern/Central Rockies along with the Sierras... ...Heavy rain possible over the Pacific Northwest... A front over the Northwest will steadily moves eastward to the Northern/Central Plains and Southern High Plains by Saturday. The system will produce rain, heavy at times over parts of Northern California and the Pacific Northwest that will move eastward into the Northern Intermountain Region and into Central California by Friday morning. As the boundary moves inland the snow levels will lower with snow starting overnight in the higher elevations of the Cascades and the Siskiyous/Shasta with snow developing over the highest elevations of the Sierras by Friday morning. On Friday, snow and lower elevation rain will develop over parts of the Northern Intermountain Region/Northern Rockies into parts of the Great Basin that will expand into the Central Rockies with rain over the Northern High Plains by Saturday morning. Behind the front, onshore flow will aid in continuing the rain and higher elevation snow over Pacific Northwest and Northern California through Saturday, with heavy rain returning to the Pacific Northwest on Saturday. Meanwhile, upper-level energy over parts of the Southwest/Great Basin and Southern Rockies/Southern High Plains will move northeastward to the Upper Mississippi Valley/Upper Great Lakes by Saturday. Moisture will also stream northward over the Southern Plains moving northward to the Upper Mississippi Valley by Saturday morning. Showers and thunderstorms will develop over parts of the Southern Rockies/Southern High Plains and the Western Gulf Coast Thursday night into Friday morning. On Friday, the showers and thunderstorms will consolidate over the Southern Plains, continuing over parts of the Southern Plains through Saturday. In addition, as the Plains and Mississippi Valley moisten up, the front from the Northwest moves into the Northern/Central Plains aiding in developing showers and thunderstorms along and ahead of the boundary over parts of the Central/Northern Plains overnight Friday that will expand into parts of the Upper/Middle Mississippi Valley by Saturday. Elsewhere, easterly flow off the Atlantic and weak upper-level energy will aid in producing showers and thunderstorms over Florida's East Coast into Southern Florida that will retreat to the southern half of Florida by Saturday. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php