050 FXUS63 KMPX 111017 AFDMPX Area Forecast Discussion National Weather Service Twin Cities/Chanhassen MN 417 AM CST Mon Feb 11 2019 .SHORT TERM...(Today through Tuesday) Issued at 417 AM CST Mon Feb 11 2019 The system that will be responsible for our heavy snow chances later tonight and tomorrow is clearly evident on water vapor imagery, as a trough begins to dig over the southwestern US. Cyclogenesis will occur today in the lee of the Rockies with guidance continuing to show a more southerly storm track taking the low across Oklahoma, through central Illinois, and up through southern Michigan. The trend towards delaying deepening of the surface low until it is well to our east has continued as well, with the surface low now not reaching 990 mb until it is already into Ontario. With the 700 mb low now taking a more southeasterly track as well, we've seen another shift east with the heaviest snowfall amounts. Guidance now show the highest probabilities of seeing greater than 0.5" of QPF over central and southern Wisconsin, with our west-central Wisconsin counties on the western edge of this region. While the higher-end snowfall amounts now look to fall to our east, we're still dealing with enough moisture for heavy snow. With snow ratios expected to be around 15-16:1 during the event, we're still anticipating the potential for 6-10" of snow from southeast Minnesota through western Wisconsin and have issued a Winter Storm Warning to begin later tonight. Further west, have kept the Winter Storm Watch to account for the uncertainty of any more of an eastern shift with the heavy snow. Accumulating snow is still expected, but will wait until the afternoon to decide on any new Winter Storm Warnings or Advisories. Regarding timing, forecast soundings show a considerable dry layer in the mid-levels so have delayed the onset of snowfall by a few hours to account for the time needed to saturate that layer. We can't rule out a brief period of freezing drizzle at precipitation onset before the atmosphere saturates enough for ice crystal develop, but any ice accumulation should be negligible. Expect snow to begin across southwest Minnesota by late afternoon, the Twin Cities metro after the evening commute, and by midnight across west-central Wisconsin. The heaviest snowfall is expected overnight Monday through Tuesday morning, so the Tuesday morning commute looks to be especially impacted. Snow should taper off by late morning across western Minnesota, late afternoon from central through southern Minnesota, and Tuesday evening across western Wisconsin. Finally, winds will pick up Tuesday afternoon on the back side of this system, with wind gusts up to 30 mph possible across western and southern Minnesota. With the strongest winds occurring after the snow ends and in areas outside of the heaviest accumulations, expecting some areas of blowing and drifting snow but widespread travel impacts look to be minor. .LONG TERM...(Tuesday night through Sunday) Issued at 417 AM CST Mon Feb 11 2019 Looking at the large scale pattern, not much changes with the going theme we've see all month, with mean troughing over western NOAM and ridging over the southeast. The biggest change we see this weekend into next week is that it does appear the storm track will shift south, so we'll at least get a break from the repeat snows. Although we may quiet down in the precipitation department, one thing that we can say with a fairly high degree of certainty is that there are no significant warmups at any point in our future over the next two weeks as we look to maintain our run of below normal temperatures, though we are not seeing any signs of any extreme cold. We'll start the period with Tuesday's system heading northeast out of the Great Lakes. We'll have high pressure coming in at the surface, but we'll actually have warm advection at h85, with temps at that level going above 0C over southern MN by Thursday morning. This warming occurs out ahead of the next arctic boundary, which will come through Thursday night. The GFS continues to be a strong outlier with the system it develops to our southeast, and therefore is overdone one it's snowfall. Prefer an ECMWF/GEFS solutions, which brings QPFs of 0.1-0.2" across our area, which would translate into a quick 1-3". For the rest of the period, the jet shifts south and this will take the precip chances with. The one thing we will have to watch with temperatures as we shift into a drier and likely sunnier pattern is that we'll start seeing a significant albedo influence to daily highs with our tree covered areas in western Wisconsin warming significantly more on sunny days than we see in the more open plains of western Minnesota. && .AVIATION...(For the 06Z TAFS through 06Z Monday night) Issued at 1114 PM CST Sun Feb 10 2019 Cigs will be deteriorating overnight to IFR across much of the area. Little improvement is expected Monday. Snow will advance northeastward Monday evening, reaching most of the TAF sites before 06Z Tue. KMSP...MVFR cigs are likely to drop to IFR overnight before rising back to MVFR Monday morning. Snow still looks to arrive after 04-05Z Tue with LIFR visibilities expected. /OUTLOOK FOR KMSP/ Tue...IFR/LIFR with significant snow accums possible early. Wind NE 10 kts in morning, bcmg NW 15G25 kts in aftn. Wed...VFR. Wind W 5-10 kts. && .MPX WATCHES/WARNINGS/ADVISORIES... WI...Winter Storm Warning from midnight tonight to midnight CST Tuesday night for WIZ015-016-023>028. Winter Storm Watch from this evening through Tuesday evening for WIZ014. MN...Winter Storm Watch from this evening through Tuesday afternoon for MNZ053-060>063-068>070-076-077. Winter Storm Watch from this evening through Tuesday afternoon for MNZ083>085-091>093. Winter Storm Warning from 9 PM this evening to 9 PM CST Tuesday for MNZ078. && $$ SHORT TERM...ETA LONG TERM...MPG AVIATION...BORGHOFF