902 FXUS63 KMPX 142112 AFDMPX Area Forecast Discussion National Weather Service Twin Cities/Chanhassen MN 312 PM CST Wed Dec 14 2022 .SHORT TERM...(This evening through Saturday Morning) Issued at 310 PM CST Wed Dec 14 2022 KEY MESSAGES: - Snowfall returns tonight, with heavy snowfall expected from central Minnesota through western Wisconsin through Thursday. - The heaviest snow will fall Thursday morning, where forecast amounts of 3-6" are expected during a short period of time leading to travel hazards during the morning commute. - Light snow continues Thursday night through Friday. Precipitation has mostly ended this afternoon across the area, as the dry slot of a well-developed area of low pressure sits over the region. Winter weather will return tonight as the dry slot exits the region, and very strong forcing aloft move over the region as the surface & upper-level lows move directly over the area. The strongest forcing arrives tonight through tomorrow morning, as a potent shortwave pivots around the low from the southern Plains directly into the upper Mississippi Valley. This will cause the already mature surface low to actually reintensify over the area tomorrow, and lead to a 6-8 hour window of heavy snow expected from central Minnesota through western Wisconsin. Light rain/drizzle will become more widespread this evening as forcing begins to increase over the region and temperatures remain above freezing. As the strongest forcing from the shortwave arrives tonight, surface temperatures are expected to dynamically cool closer to freezing which will result in a changeover from rain to snow from east to west around midnight. Deterministic and ensemble consensus is high in QPF amounts greater than 0.5" during a 6-8 hour window across west-central Wisconsin, and between 0.3 to 0.5" across central and eastern Minnesota. These liquid precip amounts coupled with forecast snow ratios around 10:1 mean snowfall accumulations of 4-6" across western WI and 2-4" across central & eastern MN falling during a relatively short window of time. Model consensus is also high for this burst of heaviest snow occurring during the overnight hours across western Wisconsin, and early to mid-morning across central and eastern Minnesota. Snowfall rates around 1" per hour during this time along with the wet & heavy nature of the snow means major travel impacts are expected during the morning commute. Snowfall rates will gradually diminish through the morning and afternoon as the strong forcing from the shortwave moves north of the area. However, light snow is expected to continue falling all the way through Saturday morning as the fully matured area of low pressure slowly sits and spins over the region. Snowfall accumulations are only expected to be on the order of of 1-2" every 12 hours starting Thursday afternoon, but this will still lead to another 2-4" of snowfall accumulation on top of the snow that will have accumulated by the end of Thursday morning. All in all, the highest snowfall accumulations of 8-12" by Saturday morning are expected in western Wisconsin, generally along and east of a Polk- Eau Claire county line in western Wisconsin. Total amounts of 4-8" are expected across central and eastern Minnesota, while amounts should be generally around 3-4" or less across southern Minnesota A Winter Storm Warning has been issued until Friday night across central & eastern Minnesota through western Wisconsin - where the heaviest snow and greatest travel impacts Thursday morning are expected. A Winter Storm Advisory has been issued for south-central Minnesota where lesser snowfall accumulations and travel impacts are expected. .LONG TERM...(Saturday through Wednesday) Issued at 310 PM CST Wed Dec 14 2022 Key Messages: - Light lingering snow will come to an end on Saturday. - High confidence in below normal temperatures through the end of the year. After this week's messy weather, a break in excitement will arrive later in the day on Saturday. A few hours of light snow to the east of the Twin Cities is possible, but things should be quiet on the precipitation front at least through Tuesday. Saturday onward will, however, bring chilly arctic air to the region as the trough departs eastward. Northwesterly winds will hold strong for at least a couple of days, giving no reprieve from the single digit high temperatures currently forecast for late weekend into early next week. This is good news for those who are prepping back yard ice rinks and wishing for a white Christmas, as Friday will likely be the last time in 2022 that we will see above freezing temperatures. By late Tuesday into Wednesday of next week, the signal remains for some snow across the CWA as a Canadian low pressure system will dip south of the border. Model discontinuities exist, so not much more can be said on this potential system other than there is a chance for more snow by the middle of next week. Given the forecast temperatures, P-types won't be an issue with any precipitation that does fall. && .AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon) Issued at 1242 PM CST Wed Dec 14 2022 Precipitation has mostly ended at area terminals this afternoon, outside of some intermittent drizzle. IFR ceilings already exist over the area and will only trend lower as precipitation returns this evening. Visibility will drop to MVFR/IFR levels late this afternoon & evening as drizzle become more widespread. Drizzle/light rain will then transition over to snow around midnight across central MN & western WI terminals, and during the early morning across western Minnesota. Visibility around 1SM is expected during the snow, with periods down as low as 1/2SM possible in the hours before sunrise. The snow will continue through the morning, but gradually diminish in intensity with visibility likely reaching MVFR by the end of the period. IFR ceilings are expected to persist through the period. Continues easterly winds will persist into this evening, with gusts around 20 kts diminishing by tonight. Winds will back from easterly to northerly overnight and through the morning as the surface low passes over the area. Speeds will diminish to below 10 kts overnight and remain around 10 kts or less through the morning. KMSP...Drizzle will become more widespread this evening with visibility gradually becoming more MVFR. Expect snow to begin at the terminal around midnight, with visibility quickly dropping to around 1SM as the snow begins. A few hours of visibility approaching 1/2SM is possible during the heaviest snow, which is mots likely between 2-6 AM. Snowfall accumulation of 2-4" is expected leading up to & during the morning rush. Snowfall intensity will gradually diminish through the morning, but intermittent MVFR snow is likely into the afternoon. Winds will slowly back from easterly to northeasterly this evening and through the overnight hours. Winds are expected to become more northerly as opposed to northeasterly by 5-6 AM. /OUTLOOK FOR KMSP/ Sat...MVFR cigs likely. Wind NW 10-15 kts gusting to 25 kts. Sun...MVFR cigs possible. Wind W 5-10 kts. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...Winter Storm Warning from 3 AM to 9 PM CST Thursday for Chippewa- Douglas-Kandiyohi-Lac Qui Parle-Meeker-Pope-Stearns-Stevens- Swift-Todd-Wright-Yellow Medicine. Winter Storm Warning from midnight tonight to 6 PM CST Thursday for Anoka-Chisago-Dakota-Hennepin-Isanti-Kanabec-Mille Lacs- Morrison-Ramsey-Washington. Winter Storm Warning from midnight tonight to 9 PM CST Thursday for Benton-Sherburne. Winter Weather Advisory from 3 AM to 9 PM CST Thursday for Blue Earth-Brown-Carver-Faribault-Freeborn-Le Sueur-Martin-McLeod- Nicollet-Redwood-Renville-Rice-Scott-Sibley-Steele-Waseca- Watonwan. Winter Weather Advisory from 9 PM this evening to 6 PM CST Thursday for Goodhue. WI...Winter Storm Warning from midnight tonight to 6 PM CST Thursday for Barron-Polk-St. Croix. Winter Storm Warning from 9 PM this evening to 6 PM CST Thursday for Rusk. Winter Storm Warning from 9 PM this evening to 3 PM CST Thursday for Chippewa-Dunn-Eau Claire-Pepin-Pierce. && $$ SHORT TERM...ETA LONG TERM...PEM AVIATION...ETA