Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 309 PM EST Thu Dec 08 2022 Valid 00Z Fri Dec 09 2022 - 00Z Sun Dec 11 2022 ...Episodes of moderate to heavy rain expected to track across the Southern Plains to the Mid-Mississippi Valley the next couple of days... ...Wintry weather spreading into the Central/Northern Plains today and into the Upper Midwest on Friday... ...Heavy precipitation expected for the Pacific Northwest and northern California today before significant mountain snowfall arrives tomorrow... As has been the story the last few days, a meandering cold front interacting with an energetic subtropical jet will continue to trigger episodes of active weather across the south-central portion of the mainland U.S. A complex of moderate to locally heavy rain persists along said front this afternoon over the mid-Mississippi/Tennessee Valley, piling onto the 2-3 inches of rainfall over the region this past week. Fortunately, no flash flood issues are expected from this activity as the rainfall is expected to gradually wane in intensity as it migrates toward the Mid-Atlantic tonight. Behind this moisture stream, low pressure is forecast to develop along the front and move across the Central Plains tonight and into Friday with a renewed round of moderate rainfall tracking through the Mid-Mississippi and Tennessee Valleys tonight into Friday. No excessive rainfall threat is anticipated from this additional rainfall. North of the track of the low pressure wave, cold temperatures are supporting mixed precipitation (including freezing rain and drizzle) and snow over the Central/Northern Plains, which should reach the Upper Midwest by Friday morning. A few inches of snow and a glazing of ice is expected roughly along I-90 over eastern South Dakota through southern Wisconsin beginning later today. Accordingly, a swath of Winter Weather Advisories extend through Friday morning over portions of the I-90 corridor. This system is forecast to quickly dissipate on Friday as it reaches the Great Lakes. However, another low pressure wave is forecast to form once again over the Central High Plains Friday night and then track quickly to the east, bringing another around of moderate to locally heavy rain to the same general region from the Southern Plains eastward to the Mid-Mississippi Valley by Saturday morning. Meanwhile, unsettled weather is in store for the West Coast as a couple of broad and energetic systems from the Pacific are in the forecast. Low elevation rainfall, heavy high elevation snows, and gusty winds from the first system continue this afternoon over portions the Pacific Northwest and California. By tonight, the occluded low pressure is forecast to weaken as it spreads into the Great Basin. However, remnant Eastern Pacific moisture streaming inland should yield inland mountain snows over much of the Intermountain Region that spreads east through tomorrow. The more robust, moisture laden storm system is forecast approach offshore portions of the Pacific Northwest by tomorrow afternoon/evening, ushering in another round of heavy low elevation rainfall and mountain snows along the West Coast through the weekend. Hourly rainfall rates possibly in excess of 0.5 inches per hour could cause isolated flash flooding issues over coastal areas of Northern/Central California tomorrow and Saturday, particularly atop any burn scar areas. In the mountains, significant high elevation snowfall is looking increasingly likely over the Cascades and Sierra Nevadas through the weekend. The latest WPC WSSI now highlights Major to locally Extreme potential winter storm impacts over the Cascades and Sierra Nevadas this weekend, where several feet of snow could fall through Sunday. A slew of Winter Storm Warnings and Watches have been hoisted this afternoon over parts of the Cascades and Sierra Nevadas through Sunday morning. Asherman/Kong Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php