Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 232 AM EST Wed Nov 20 2019 Valid 12Z Wed Nov 20 2019 - 12Z Fri Nov 22 2019 ...Heavy mountain snow over the Central/Southern Rockies as well as the Great Basin/Southwest and moderate snow over the Northern Tier States along the border with Canada... ...There is a moderate risk of excessive rainfall over parts of the Southwest... ...There is a critical risk of wildfire spreading over parts of Northern/Central California... A long stretch of warmer and drier conditions over parts of northern/central California has primed that area for potential spread of wildfires and this airmass is expected to persist through the end of the week. As such, there is a critical risk for wildfires across northern California through Thursday morning. For the Southwest U.S., mountain snow and moderate to heavy rain in the lower elevations is expects as a deep up-level low tracks east across the region. The precipitation shield will shift into the Southern/Central Rockies/High Plains as the front approaches. The intensity and during of some of these downpours will likely lead to numerous flash flooding of many streams and potentially affecting larger rives through Thursday morning. Much of west-central and southern Arizona has a Slight to Moderate Risk for Excessive Rainfall. Rain and snow will spread across the central states and into the Upper Mississippi Valley/Upper Great Lakes region by through Friday as a low pressure system lifts northeast during this time. Light snow will fall across the higher terrain of the Northeast Low pressure over the Central High Plains will move northeastward to the Great Lakes by Thursday evening. The system will produce rain and snow over parts of the Central/Northern Plains into the Upper Mississippi Valley/Upper Great Lakes overnight Wednesday into Thursday evening. Campbell Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php