Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 300 PM EST Thu Nov 28 2019 Valid 00Z Fri Nov 29 2019 - 00Z Sun Dec 01 2019 ...Heavy snow with blizzard warnings for parts of the Northern Plains/Northern High Plains... ...There is a slight risk of excessive rainfall over parts of Arizona and Southern California... Developing deep low pressure over the Southwest will move Northeastward to the Middle Missouri Valley by Saturday evening. The storm will produce heavy rain over parts of Southern California and the Southwest producing scattered areas of flash flooding that will be mainly localized. Most vulnerable are urban areas, roads, small streams, and washes. In addition, isolated significant flash floods possible. These conditions will continue on Thanksgiving into Friday morning. The system will produce heavy snow over Sierras Nevada, Mogollon Rim, Wasatch, Uinta, and San Juan Mountains through Saturday morning. Furthermore, the storm will pull moisture northward over the Southern Plains into the Mississippi Valley on Friday into Saturday. Showers and thunderstorms will develop over parts of the Southern Plains on Friday into Saturday. Rain will also develop over of the Central Plains that will push northward into the Central Plains and Middle/Upper Mississippi Valley from overnight Thanksgiving into Saturday. A transition area will develop between the rain and snow where rain/freezing rain will develop in a narrow band over the Central Plains/Middle Mississippi Valley that will move northward over the area into Northern Plains/Upper Mississippi Valley Friday night into Saturday. The second and more impactful storm system currently over the Intermountain West remains a very large system with impacts expected across a large portion of the western and central U.S. through the end of the week. Heavy snow is likely through the end of the week from the Sierra Nevada to the central and northern Rockies. Snowfall totals across many of these regions are likely to be in the 1 to 2 foot range. By Friday, snow is forecast to develop across the northern Plains where winter storm watches are now in effect. Farther to the east, a separate area of rain will be drawn northeastward ahead of the western storm system across the southern Plains through Friday. There is a Marginal Risk for both excessive rainfall and severe thunderstorms across portions of Texas and Oklahoma. Dry weather will continue across the Southeast U.S. and Mid-Atlantic region to close out the week. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php