Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 316 AM EDT Sun Oct 20 2024 Valid 12Z Sun Oct 20 2024 - 12Z Tue Oct 22 2024 ...Heavy Rain and light to moderate Snow across portions of the Central Rockies, and Southern High Plains today before diminishing tonight... ...Rainfall for the Pacific Northwest through Monday... ...Expansive area of above average temperatures settle over the northern tier... An anomalous closed upper-level low pressure system will continue to produce heavy rainfall and scattered thunderstorms across portions of the Southern High Plains through this morning before quickly tapering off this afternoon and evening. A Slight Risk of Excessive Rainfall leading to Flash Flooding is in effect for parts of far southeastern Colorado, the Texas/Oklahoma panhandles and northeastern New Mexico where 1 inch/hr rain rates could cause runoff concerns, particularly over recent burn scars. Heavy snow is also a concern over parts of the Central Rockies, specifically the San Juans above 10,000 feet where over 8 inches of snow are possible. Snow tapers off tonight as the upper low moves away into the Great Plains. A broad positively tilted upper trough will continue generating a prolonged weak atmospheric river event over the Northwest over the next couple of days. Some additional 1-2 inches of rainfall are possible for parts of the Pacific Northwest today followed by portions of the Northern Rockies on Monday. Any snow that falls will be confined to the highest elevations of the Cascades. An upper ridge will promote warm southerly flow into the Plains and eventually East over the next several days. High temperatures in the 70s and 80s today and Monday will represent 20-30 degree positive anomalies for this time of year over parts of the Upper Midwest. Overnight temperatures will be warm enough to rival low records as well. Troughing over southern Canada and the cut-off low propagating across the Plains will eventually push the warm air into the eastern half of the country this week. Kebede Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php