Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 350 PM EDT Mon Oct 28 2019 Valid 00Z Tue Oct 29 2019 - 00Z Thu Oct 31 2019 ...Heavy snow across the Central Rockies/High Plains... ...Record cold temperatures at many locations over the Northern/Central Rockies and into the High Plains... ...Critical to extreme fire weather threat over parts of Northern and Southern California... A deep upper-level low over Central Canada will send surges of cold air from Western Canada into the Western and Northern U.S.. A very cold air mass is currently establishing across Western Canada. The upper-level low over Central Canada will begin to push this cold air mass southward into the western half of the U.S.. With temperatures ranging from 25 to 45 degrees below average over the Northern/Central Rockies and the Northern, Central, and Southern High Plains. Upslope flow associated with a developing area of cold high pressure will aid in producing snow, heavy at times, over parts of the Northern/Central Rockies and Northern/Central High Plains that will end over the Northern Rockies by Tuesday evening and by Wednesday evening over the Central Rockies. Winter Weather Warnings and Advisories are posted over parts of the region. The snow will produce slippery roads with blowing snow, reduced visibilities. The cold and wind will produce wind chills as low as 25 below zero that could cause frostbite. In addition to the cold and the snow, winds will be quite strong and gusty especially over the higher terrain as an expansive high pressure system builds in from Canada. Meanwhile, a front will move every slowly from the Upper Great Lakes to the Southern Plains eastward to the Lower Great Lakes/Northern Appalachians by Wednesday, the front will be quasi-stationary. Moisture overrunning the front and upper-level energy will aid in producing snow over parts of the Central Plains/Middle Mississippi Valley and rain over parts of the Middle/Lower Mississippi Valley overnight Monday. By Tuesday morning, the rain and snow will move into the Upper Great Lakes/Upper Mississippi Valley. The rain and snow will end over the Upper Great Lakes by Wednesday morning. On Tuesday, showers and thunderstorms will develop over parts of the Western Gulf Coast/Southern Plains continuing into Wednesday evening. Additional upper-level energy will move out of the Great Basin will aid in producing more snow over parts of the Central Plains into parts of the Middle Mississippi Valley by Wednesday evening. Over California, continued dry and windy conditions will promote critical to extreme fire weather threat for parts of Northern and Southern California. An expansive high pressure system will build into the area on Tuesday. Winds are expected to pick up on Tuesday lasting into Wednesday which will increase the fire threat even into the interior section of the Southwest. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php