Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 400 AM EDT Mon Oct 28 2019 Valid 12Z Mon Oct 28 2019 - 12Z Wed Oct 30 2019 ...Heavy snow across the central Rockies and High Plains Tuesday into Wednesday... ...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 today... A deep upper-level vortex over central Canada continues to 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 vortex over central Canada will begin to push this cold air mass southward into the western half of the U.S. Snow is already falling over Montana ahead of the leading edge of the cold air. The snow is expected to push southward steadily across the northern Rockies today, and then into the central Rockies and nearby High Plains on Tuesday. Widespread 6 to 12 inches with locally high amounts are likely to accumulate in these areas. The snow will also be accompanied with very cold temperatures. In fact, record low temperatures are expected at many locations as readings dip to below zero at the coldest locations by Wednesday morning. In addition to the cold and the snow, winds will also be strong and gusty especially over the higher terrain as an expansive high pressure system builds in from Canada. M The front associated with the leading edge of the cold air associated with the area of high pressure will move into the Great Lakes to the Southern Plains that will be quasi-stationary through Tuesday evening. Some moisture will pool along the front as upper-level energy aids in producing an area of snow and rain over parts of the Central Plains into Middle Mississippi Valley by Monday afternoon. The area of snow and rain will move into the Great Lakes overnight Monday and begin to wane by Tuesday evening. Rain will move into parts of the Southern Plains/Lower Mississippi Valley overnight Monday, too. On Tuesday, showers and thunderstorms will develop over parts of the Western Gulf Coast as rain moves into parts of the Western Ohio Valley. The rain and thunderstorms will continue over parts of the Southern Plains and the Western Gulf Coast through Tuesday evening. Kong Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php