JACKSON, Wyo. – A storm will impact Wyoming on Thursday but east to southeast winds will limit the heavy snow potential in Teton County. While Jackson will see some snow, totals will be much heavier across Central Wyoming including Lander, Riverton, and Casper.
Thursday Storm
A complex storm involving a closed low will impact Wyoming on Thursday. Closed lows are notoriously tricky from a forecasting perspective in our region, as they involve winds circumnavigating a low pressure center in a clockwise (cyclonic) direction.
This is different from the progressive open wave cyclones we often see during the winter, with southwest, west, or northwest winds that often bring heavy snow to the Tetons.
Closed lows are more common in the spring and fall when temperature gradients between warm and cold airmasses are sharper, causing the jet stream to slow down and become more meridional, or “wavy”.
When a closed low tracks in the right direction, it can bring significant precipitation to the Tetons. But often, we see winds with an easterly component (blowing from the east) which is unfavorable for precipitation in the Tetons, and more favorable for areas east of the Continental Divide.
This particular system will pass just south of our area, placing Teton County under a southeast to east flow.
Here is a radar projection for midday Thursday:
Southeast winds can bring some moisture into Southern Teton County, so we should see some decent snow accumulations around Snow King and Teton Pass with lighter amounts expected further north in the Tetons, including Jackson Hole Mountain Resort.
The town of Jackson will also see accumulating snowfall on Thursday morning and it could be a slow morning commute in the valley and over the pass with slushy snow conditions expected. By late morning to midday, temperatures will be warm enough in the valley for melting to occur.
On the west side, Teton Valley could potentially see decent snow accumulations as well due to converging winds in the vicinity of the low pressure center.
The east side of the Continental Divide, including the eastern Wind River Range and Wind River Basin, will see some of the highest snowfall totals in Wyoming. Lander and Riverton will see significant snowfall totals, and Casper will be impacted as well.
In fact, a large portion of Southern, Central, and Eastern Wyoming will see heavy snow from this storm with significant travel impacts on Thursday and through at least the first part of the day on Friday.
A large portion of Central Wyoming is under a Winter Storm Warning from the National Weather Service in Riverton.
Weather Outlook Beyond Thursday
Jackson Hole and Teton County will begin to dry out on Friday with lingering clouds expected.
From Saturday to Monday, a ridge of high pressure will build over the Central Rockies, resulting in dry and sunny conditions. In the Jackson Hole Valley, highs will reach the upper 30s to low 40s with lows in the teens.
The next storm is expected to arrive around Tuesday (March 11). This will likely be the start of an active pattern with frequent storms possible through mid-March along with temperatures trending below average for this time of year.
Snowpack Update
Snowpack in the Tetons remains slightly above average following a very snowy February. Based on snow water equivalent at remote stations across the Greater Teton Region, snowpack is currently 106% of average.
The active pattern expected during mid-March is good news for the snowpack as this may help to keep us near to above average. The average peak snowpack in the Tetons occurs during the second week of April.
Alan Smith, Meteorologist
