Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 252 PM EDT Mon Oct 10 2016 Valid 00Z Tue Oct 11 2016 - 00Z Thu Oct 13 2016 ...Heavy snow is likely across much of southern Montana through Tuesday... ...Much colder weather in store for the Northern Rockies into the Northern/Central Plains... What remains of Post-Tropical Cyclone Matthew has become absorbed into an impressive upper trough currently lifting out of coastal New England. In its wake, surface high pressure has built in across the Eastern Seaboard leading to clear skies pretty much up and down the coast. Conditions ideal for sufficient radiational cooling are in place tonight which has led to frost advisories and freeze warnings being issued from Pennsylvania northward to lower Maine. A pronounced system tracking through the Upper Intermountain West and Northern Rockies has spread moderate to locally heavy snow over the higher elevations of Montana. Thus far, 15 inches of snow has already been reported at East Glacier Park. The current winter weather forecast indicates the heaviest snows will be across south-central Montana where 6 to 10 inches should be likely. As such, local forecast offices across this region have put out Winter Weather Advisories through Tuesday afternoon. Beside the threat for snow, the accompanying cold front will bring rather chilly conditions to the region with high temperatures barely making it to the freezing mark on Tuesday across central Montana. Based on average highs for early to mid-October, this suggests readings around 20 to 25 degrees below climatology. Such cooler air will work its way eastward with anomalies in the 10 to 15 degree range for the Northern/Central Plains for Wednesday. The biggest threat for rain this period will be in response to a slow-moving upper trough currently moving through central Kansas. Recent moisture availability across the United States is meager out of the Gulf of Mexico with a frontal boundary stalled south of there. However, there does appear to be a narrow strip of appreciable moisture moving up through the Rio Grande Valley into the Southern/Central Plains. This source of moisture combined with the energetics from the upper trough should help focus a band of rainfall into Missouri and southern Illinois. As this system further migrates northward, expect a swath of light to moderate rain to expand into the Upper Great Lakes along the slow-moving cold front. Lastly, there is an enhanced threat for brush fires across eastern Wyoming and the western Nebraska Panhandle given strong downsloping flow accompanied by very low relative humidities. The Storm Prediction Center fire weather desk indicates a critical risk in their outlook which extends through Tuesday morning. Rubin-Oster Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php