Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 416 AM EDT Tue Oct 29 2019 Valid 12Z Tue Oct 29 2019 - 12Z Thu Oct 31 2019 ...Heavy snow across the central Rockies/High Plains spreading into the central Plains... ...Widespread record cold temperatures expected for interior western U.S., later spreading into the central/southern Plains... ...Critical to extreme fire weather threat over parts of Northern and Southern California... A deep upper-level low over central Canada is bringing the coldest air mass thus far this season down from western Canada into the northern Rockies and into the northern Plains. This surge of arctic air is poised to bring heavy snow for the Rockies together with widespread record cold temperatures into much of the interior western U.S., even into the central and southern Plains during the next few days. Temperatures are forecast to be 25 to 45 degrees below average, with actual readings dipping below zero at the coldest locations over the northern and central Rockies. In addition to the arctic cold, up to a foot of heavy snow is expected to fall today over the Colorado Rockies and out into the High Plains of northeastern Colorado. The winds will also pick up as the heavy snow falls, and they could be enhanced by local terrain as an expansive high pressure system builds in from the north. Blowing snow along with wind chills as low as 25 below zero could be experienced in these areas. By Wednesday evening, much of the snow should be exiting the central Rockies and moving into the central Plains. The snow should then reach the upper Midwest Wednesday night where up to 6 inches could accumulate by Thursday morning. This is in response to the development of a low pressure system over the southern Plains as it moves rapid toward the Mid-Mississippi Valley Wednesday evening and into the Appalachians Wednesday night. Meanwhile, above to well above normal temperatures are expected to persist over the eastern U.S. As the aforementioned low pressure system rapidly develops, scattered showers and thunderstorms are expected to spread into the Ohio Valley on Wednesday. In the mean time, strong thunderstorms appear likely ahead of a strong cold front as it moves across the mid and lower Mississippi Valley. 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 today. Winds are expected to pick up again today and will last into Wednesday. This will increase the fire threat even into the interior section of the Southwest. Kong Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php