Pattern coming alive on both coasts…

Thanks to snowmaking and a nice dump of fresh snow last Friday, I kicked off my season with a nice day on the trails of Killington this past Tuesday. The surface midwinter stuff and it was fantastic to be making turns again. The storm late last week helped out across much of the Northeast, but more is needed not only in that region, but across the entire country, as trail counts and opening dates are lagging nationwide this year. Fear not, though…help is on the way!

The current jet stream setup has been in place for a few weeks now, with a western upper ridge coupled with a broad trough over the eastern half of the country, as illustrated by this map, valid the morning of the 3rd….

The ridge (orange) has kept the West high and dry while the trough (blue) further east has supported weak systems that have spun through the Lakes into the Northeast. Each one of those disturbances has delivered a modest shot of colder air, allowing snowmakers from Ontario and Quebec to North Carolina to get the season rolling on a limited basis. The trough will remain in place for the next several days, but by the 6th, changes will get underway. A new trough will dive into the center of the country and deliver a significant shot of cold air…good news in the upper Midwest. To the east, a mild upper ridge will pop up in response, with low pressure taking a track between the two jet stream features, from the mid-Mississippi Valley up through the Great Lakes and on toward Toronto and Montreal. In the East, that track will produce rain and then snow as cold air rushes in on the backside of the storm. Next, a weaker midweek disturbance will bring light to moderate snow from the central Appalachians into New England and eastern Canada.

The biggest pattern change is coming to the West and not a moment too soon with the holidays just a few weeks away. While the initial thrust of cold air will move into the northern Plains, several additional systems will move south from Canada in the coming week, breaking down the ridge in the process. The first will impact the far northern Rockies and southern Canada this weekend, the second will reach the central ranges Monday and Tuesday, and then a late week trough will dive all the way into the Southwest, producing the biggest snowfall of the young season in the southern Sierra and Rockies as it does. Here is a forecast of snowfall through next Friday night…

You can see that significant, beneficial snow can be expected not only in the West, but also in the upper Midwest and the northern regions of New York and New England. Deep cold is still a little tough for the pattern to access, so snowmaking will still be hit and miss in the near term. Longer term, the week of the 13th will bring a western cold trough/eastern mild ridge couplet, with the potential for a nationwide cold and snowy pattern developing the week of the 20th. Here are the regional highlights…

Northwest U.S./Western Canada: Snowy week unfolding…snow levels lower than recent two weeks will help.

Sierra: Dry start, but pattern turns snowy mid to late week onward(north to south)
Rockies: Snowy pattern develops from northern (early week) to central and southern resorts (mid to late week).

Midwest: Favorable storm track and cold period unfolding next 1-2 weeks. Trail counts and bases will grow quickly.

Mid Atlantic/Southeast: Mild weekend/early next week. Colder air supports snowmaking and some snow by midweek.

Northeast/QB: Cold weekend with some light snow. Rain and backside snow early in the week. Light to moderate snowfall midweek.


  1. Herb what’s the source of your Jet Stream Chart? I have tried using netweatherglobal jet stream chart and am not sure if it is “real time” or prediction.

    Asked NWS and the best they came up with is the Aviation upper winds.

    What do you use?

  2. herb stevens says:

    Austin: is where you want to go. Good variety of forecast maps that are easy to read.


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