Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 427 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 of snow 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 be quite strong and gusty especially across the higher terrain as an expansive high pressure system builds in from Canada. Meanwhile, snow is also falling across the central Rockies this Monday morning behind the cold front associated with the previous cold surge from Canada. The snow is expected to move into the central Plains today and through the upper Midwest this evening. A band of mixed precipitation is also expected farther to the east, while rain is expected for the Midwest and the central Great Lakes near the cold front. Farther south, rain is forecast to expand across the southern Plains on Tuesday into Tuesday night as the cold front slows down and begins to interact with moisture coming up from the Gulf. A band of mixed precipitation is also expected across the central Plains as the area of snow from the central Rockies approaches. Meanwhile, the return of tropical moisture from the Gulf of Mexico will bring more numerous showers and thunderstorms into the Deep South and into the Southeast. Over California, continued dry and windy conditions will promote critical to extreme fire weather threat for areas of the northern and southern parts of the state today. The threat should ease somewhat tonight. However, an expansive high pressure system will build into the area on Tuesday. Winds are expected to pick up again on Tuesday lasting into Wednesday which will increase the fire threat even into the interior section of the southwestern U.S. Meanwhile, warmer than normal temperatures are expected to persist for the eastern U.S. Kong Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php