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ACUS11 KWNS 060209SWOMCDSPC MCD 060209ILZ000-WIZ000-IAZ000-060345-Mesoscale Discussion 0201NWS Storm Prediction Center Norman OK0809 PM CST Sat Mar 05 2022Areas affected...Northern and Central Illinois...far southernWisconsinConcerning...Severe potential...Watch possibleValid 060209Z - 060345ZProbability of Watch Issuance...60 percentSUMMARY...A severe thunderstorm watch will be considered forportions of northern and central Illinois. Strong wind fields willsupport damaging wind gusts despite weaker thermodynamics.DISCUSSION...Strengthening 850 mb winds have been observed byregional VWP with winds reaching 50-60 kts. Cooling aloft and modestmoisture transport into Illinois and southern Wisconsin shouldsupport areas of increasing, but weak, buoyancy this evening. Asconvection moves eastward out of Iowa, the trend in storm mode isexpected to become more linear. At present, a line of storms nearingthe Mississippi River in southeastern Iowa has shown an increase inlinear organization and has had measured severe winds within thelast hour. While there are some uncertainties as to how organizedthis activity remains, even modest buoyancy is expected to supportsevere wind gust potential given the strong wind fields just a abovethe surface. Brief tornadoes within QLCS circulations are possible,but are not expected to be the main threat. A severe thunderstormwatch is possible later this evening...Wendt/Thompson.. 03/06/2022...Please see www.spc.noaa.gov for graphic product...ATTN...WFO...LOT...ILX...MKX...LSX...DVN...ARX...LAT...LON 40999030 41969028 42639043 42738982 42678901 4231884540478849 39678900 39338958 39399022 39569072 3996906740999030FOUS11 KWBC 052100QPFHSDProbabilistic Heavy Snow and Icing DiscussionNWS Weather Prediction Center College Park MD359 PM EST Sat Mar 05 2022Valid 00Z Sun Mar 06 2022 - 00Z Wed Mar 09 2022...Western U.S....Days 1-3...The upper low currently dropping southeast across California andthe southern Great Basin will move east through Sunday across theFour Corners region. Locally strong forcing associated with theheight falls coupled with favorably moist upslope flow will resultin areas of heavy snow for areas of the Wasatch and the centralRockies. The heaviest accumulations are expected to be over thesouthwest facing slopes of the San Juan Mountains in southwestColorado where amounts locally in excess of a foot are expected.The Wasatch and Uinta Range of Utah, and the Wind River Range ofwestern Wyoming are likely to see totals of as much as 6 to 12inches. For Sunday night and Monday, a new upper trough diggingdown from the northern Rockies will help to gradually eject theupper low/trough crossing the Four Corners out into the Plains. Acombination of the departing energy and the arrival of new energywill support a few inches of new snow, and especially the Coloradohigh country for this period.Meanwhile, a new and broad upper trough will impinge on thePacific Northwest and the northern Rockies Monday night throughTuesday, and a cold front will be seen dropping southeast fromAlberta and Saskatchewan. Relatively moist deep layer northwestflow over the Washington Cascades and the northern Rockies alongwith embedded shortwave energy should result in the development oforographically driven snow showers. Meanwhile, low-levelpost-frontal upslope flow especially into the east-facing slopesof the northern Rockies and far northern High Plains will be inplace by late Tuesday, and this will also couple with the moistureand energy aloft for areas of northwest and central Montana to seeexpanding areas of moderate to locally heavy snow. Snowfallaccumulations of as much as 4 to 8 inches are expected for theseareas with locally heavier totals approaching a foot by the end ofthe period....Midwest to the Northeast...Days 1-3...Surface low pressure crossing the Upper Midwest this evening alongwith an associated mid-level trough will advance through the UpperGreat Lakes overnight and then quickly into southeast Canada onSunday. An axis of snow, sleet, and freezing rain is expectedalong the northwest flank of the low track. Much of the additionalfreezing rain threat will extend from areas of central Minnesotathrough northwest Wisconsin and across the U.P. of Michigan, andthis will tend to occur as the low-level flow begins to backaround and bring some low-level cold air back south as the lowcenter passes just to the south of the region. Locally heavyprecipitation will be expected as the core of the mid-levelenergy/trough crosses this evening and overnight, and some ofthese areas will likely see sufficient dynamic cooling arrive forany areas of sleet and freezing rain to changeover to a period ofsnow before ending Sunday morning. In fact, there is enough modelsupport for a swath of 2 to 3+ inch snowfall amounts from easternSouth Dakota through central Minnesota and far northwest Wisconsinas the aforementioned upper-level support lifts northeast acrossthe region. Farther downstream across areas of northern NewEngland, and especially northern Maine, this system as itapproaches tonight will be encountering a retreating cold airmass,but there is expected to be a burst of some accumulating snowSunday morning on the front end of the nose of strong warm airadvection. A brief changeover to some sleet and freezing rain isexpected too with some light icing possible before the systemgradually pulls away Sunday evening.As this system pulls way by late Sunday, additional energyejecting out across the central Plains will already be driving thedevelopment of a new wave of low pressure across the middleMississippi Valley which will then very quickly move into OhioValley by Monday morning