Got some light snow and a solid winter foundation as of Thursday afternoon January 11th, the beginning of the middle part of January and the heart of the winter season. The disturbance responsible for the snow is legit, and should bring a 2-4 inch accumulation to Mad River Glen by Friday morning. Winds will also turn more northerly behind this feature and allow temperatures to fall closer to 20 Friday morning drying out this snow and giving folks some powder to ski in. Models indicate enough drying to open the relentless overcast skies for a few hours Friday so enjoy the good visibility while we have it. Arctic air should provide more eventually, but that's at least one weather system away.
Another formidable weather system makes its approach Friday night. All of southern Wisconsin have a Winter Storm Watch and Chicago is expecting a decent accumulation by Saturday. Like its predecessor however, this storm is missing the ideal storm track mark placing us in another defensive posture ahead of the holiday weekend. In spite of this, models have been indicating that this weather system will "do what it needs to do" to keep precipitation frozen for the high country (I can't promise that for the valley areas). There's every indication of a more robust low pressure transition to the coast locking the minimal sub-freezing cold in place over northern Vermont. The initial, primary system responsible for the midwest snow is also expected to occlude, further mitigating the threat of a significant warm intrusion or extended period of rain. So what's the problem then ? Interestingly, the cluster of higher resolution models are confining the heaviest precipitation south and east of us and closer to the development of the coastal system. We actually need to pull this moisture farther north and west if we are to attain a 6-plus inch event. Not an impossible ask given the general nature of the system, but its simply not what's being shown. What is being indicated is a models snow/sleet event with a very minimal amount of rain or freezing rain possible Saturday morning. 3-6 inches high resolution model consensus with the American GFS model giving us a better event.
Lower elevations are going to contend with several hours of above freezing temperatures Saturday while the high country should see a return to sub-30 degree by the afternoon. We can expect a break in the precipitation by around mid-morning Saturday before snow showers return later in the day. We have a nice pool of instability behind this storm but we are lacking our favorite wind direction (the northwest wind). The southwest winds limit the upside on the accumulations from snow showers but we still should get some and other 1-4 inches by Sunday morning. Meanwhile, a major arctic invasion will be flooding the plains and midwest and working its way eastward slowly. Vermont will see temperatures hold in the low 20's Sunday and MLK day with some limited sun and some occasional snow flurries.
The slow eastward advance of the core or arctic chill certainly leaves the door open for the southern stream to go to work on the east coast and churn something up. We've seen multiple indications that something will materialize late on Tuesday, especially for southern and eastern New England, but the polar jet makes both the forecast and the actual occurrence a challenge. The PJ is a different animal and a slight change here can lead to big differences in outcomes. I love the combination of a formidable El Nino and arctic chill though. A storm might fail to come together one day and then pop up by surprise on another. As for the cold, we should see temperatures continue to fall Tuesday into Wednesday, recover some on Thursday into Friday and then plummet for the weekend of the 20th and 21st perhaps to the coldest levels of the season. The late week period continues to be a time frame where we could see a snow event materialize though models weren't really showing that as of Thursday afternoon.
Beyond January 21st, we appear to lose the support of high latitude blocking mechanism, though one will remain west of the Bering Sea. As this happens, the Pacific continue to have its foot off the gas and this should prevent a full scale retreat of arctic air on the North American continent. We should expect temperatures to moderate for the week ending Friday January 26th but I am not sold on a major thaw.
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