Dec 12, 2024
Daily Snow Stakes
All Snow GFS
Below is the 2, 4, 6-Day Lake Tahoe
NWS Totals for California, PNW. Surface, Wind Infrared GIFs Click to Animate
Pattern Discussion
This is the proprietary Cycle Chart that we use to forecast storms. I thought I would show you this so you can visualize how we do it.
Looking at this chart you can get a bird’s eye view of the Cycling Pattern. The colored areas to the left are resorts by region with the top of the chart in cycle 1 and the bottom is the current cycle. The blue lines represent predicted storms with the green line being a small storm for Colorado. Red boxes are Tahoe storms last cycle. Tahoe storms are a little tricky and need extra scrutiny to predict.
Like this current storm hitting the Sierra today. It did not occur last cycle but that could have been due to the lack of jet stream migration, which is why the yellow box is there. During that part of the cycle, the jet stream was still flowing thru Canada and had not lowered to the position it is flowing now.
This is one of the difficult parts of our long-range forecast, predicting what you think will happen once the flow becomes more of a winter pattern, and why we have more “busts” during this time.
This is another way to view the cycling pattern. These items are similar to the previous chart but go into more detail than just precipitation. This chart dives into the 500mb where the bulk of the storm systems track. It breaks down certain regions to pinpoint where storms, ridges, troughs as well as other Rossby wave elements are at a given interval.
Teleconnections
The Artic Oscillation (AO) is currently at -2 and is projected to briefly rise into positive territory and then return to negative in the next week. The AO influences how much cold air we have for storms.
The storm hitting the PNW and Lake Tahoe today will be infused with cold surface temperatures to produce great powder conditions. Ridgetop temps will be in the negative single digits.
This next chart is the 700mb level temps. This has a range of 7,700 to 10,500 feet.
This is the MJO or Madden Julian Oscillation chart. Currently we are in phase 5 and are projected to go into negative territory, then emerge into phase 6 growing in strength, to over “2” if this model forecast is correct by Christmas. This would be great news because this is when the Active Part of the Pattern begins.
A strong MJO adds fuel to the storms making them bigger and last longer. Coupled with the active pattern, this could be a very nice Christmas. The active pattern begins just a little right of middle in the first chart above.
Forecast
PNW
Snow showers today in the PNW with snow continuing thru Saturday night. Storm totals for the Cascades will be in the 1-2 ft range by the Saturday. The heaviest snow totals will be in the southern Cascades with Mt Hood and Mt Bachelor faring the best.
Lake Tahoe
Heavy snow today throughout the Sierra with the highest totals along the crest, Kirkwood, Dodge Ridge Palisades and Sugar Bowl should be in the 6-12 range by this evening.
Light snow showers will persist tonight and tomorrow before the next wave moves in during the day Saturday when the heaviest snow will hit. This wave should bring 1-3 feet, so stay tuned.
Utah and Colorado
Both of these two storms will weaken considerably as they move east. I do expect the snowfall totals for both systems for Friday and Saturday night and Sunday to give us a decent amount, with storm totals in the 6-12 range for the favored locations. This does not look to be a good storm for southern Utah and Colorado. Hopefully the numbers will increase, but you can see above in the cycle chart that the last time thru it was small as well.
The Next Set of Predictions
Thank you for reading the blog and as always if you have any questions, please email me at Mike@FutureSnow.co.
