Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 423 AM EDT Sun Oct 10 2021 Valid 12Z Sun Oct 10 2021 - 12Z Tue Oct 12 2021 ...Severe weather and excessive rainfall expected tonight across the southern Plains as the severe weather threat diminishes over the northern Plains/upper Midwest... ...Some heavy rain and gusty winds expected over the North Carolina coast this morning... ...Amplifying upper trough to inject some of the coldest air of the season into the West early next week with heavy mountain snow and much below normal temperatures likely... An increasingly active weather pattern continues to take shape across the U.S. mainland as a couple of strong upper-level troughs are forecast to force their way eastward through the western half of the country against the slow-moving regime near the East Coast. The first upper trough is responsible for the formation a pair of low pressure systems across the mid-section of the country. The system moving across the northern Plains this morning is responsible for triggering severe thunderstorms over parts of the Dakotas into Minnesota. This low will head into southern Canada by tonight with the threat of severe weather quickly diminishing over the upper Midwest. In the wake of this system, another low pressure system is forecast to form over the southern Plains today, where a threat for severe weather will rapidly transpire tonight over the region. The Storm Prediction Center is indicating a Moderate Risk for severe storms across central Oklahoma for tonight. The low pressure system will continue to develop and track into the Great Lakes by Tuesday morning with the threat of severe thunderstorms spreading further up the mid-Mississippi Valley to the Great Lakes Monday into early Tuesday. Along the East Coast, the National Hurricane Center continues to monitor a low pressure system forming near a stalled front just off the North Carolina coast. This system showed signs of acquiring some tropical characteristics early this morning. However, the main upper-level support is forecast to lift northeastward away from the system during the next couple of days. Some heavy rain and gusty conditions can be expected along the North Carolina coastal areas and may skirt the Virginia eastern shores this morning before edging out to sea later today. Some showers are possible to extend further north into southern New England on Monday as the associated frontal system will remain slow to exit the East Coast. Meanwhile, a frontal system tracking into the Pacific Northwest this evening is associated with a deepening upper trough diving south through British Columbia. The associated cold front is set to usher in the coldest air of the season to date in the western third of the country by Monday. In wake for the cold frontal passage, high winds will ensue from the Great Valley of California to the Desert Southwest. High Wind Watches have been issued in advance due to the heightened risk for hazardous wind gusts. Freeze Watches have also been posted for the western Nevada Basin. As the front crosses the northern Rockies, plummeting snow levels give way to periods of snow breaking out Sunday evening. By Monday, as the trough continues to strengthen, so will the evolving frontal system in the West, leading to heavy snow for the many mountain ranges in the Intermountain West. Latest snowfall forecast indicate anywhere from 6 to 12 inches (locally higher amounts possible) may accumulate in the northern Rockies, including ranges such as the Absarokas, Teton, Wind River, and Big Horns. This upper trough becomes quite intense by early Tuesday, setting the stage for copious amounts of snow in parts of the Rockies and a potential severe weather outbreak in the southern and central Great Plains. Kong/Mullinax Graphics are available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php