We have been watching for a possible shift in the pattern for the 3rd week of November. The latest forecast model runs are not in agreement but they are showing a colder and possibly more active pattern for next week. I wanted to give a brief update on that today. If you want the more detailed long-range discussion you can click back to yesterday's post.

We were watching the forecast for a breakdown of the ridge next week and a trough moving into the Pacific NW that could bring some colder air. The latest GFS model runs are digging the trough even deeper into CA now.

That would at least bring colder air with highs possibly dropping into the 40s by next Tuesday and overnight lows in the teens in the valleys and 20s on the mountains. That would be great news for snowmaking as currently, we have been having marginal to non-existent snowmaking conditions. Below you can see the forecast for below-average temperatures by the middle of next week.

The GFS model shows some light precipitation possible with the passage of the cold front, maybe some light snow showers.

We can start to look at specific storm details finally as we have a possible system within the 1-week window. Beyond a week we usually just stick to pattern forecasts as the forecast models lose a lot of accuracy with storms beyond a week.

The Canadian model is still keeping any precipitation to our north which is what most of the forecast models were showing through yesterday. The European model is now showing a cut-off low dropping down the CA coast and moving into Southern CA next Thursday-Friday pulling in some decent amounts of precipitation.

These are 3 different scenarios. All 3 would bring some cooler air and better snowmaking temperatures at night. The GFS currently brings the best chance for a dusting of snow. The European model is interesting to so we will have to watch closely as we get closer. I'll likely be posting almost daily going forward into the season.

Looking at the pattern beyond a week, the GFS ensemble mean runs have been continuing to show lower heights and an open storm door along the West Coast through the last week of November.

The GFS model shows a couple of storms possible and the ensemble mean runs continue to show increased chances for precipitation through the last week of November.

BUT, the Canadian ensembles which were leaning towards the GFS ensembles are now leaning towards the drier European ensembles. The latest runs are actually showing the high-pressure rebuilding near the West Coast through the last week of November.

With little, if any precipitation for CA.

Yesterday we talked about not getting excited because the historically more accurate European model was not showing the pattern the GFS was. It has a weaker ridge off the West Coast than the latest Canadian model runs and does showing some weak systems possibly pushing into CA the last week of the month. We will have to see if the MJO continues to be active into the Indian Ocean as the GFS is showing which may give its forecast more merit. 

Until then, at least we have some colder air possibly coming next week and something of interest to watch.

Stay tuned...BA

P.S. If you are looking at the forecast models I would suggest not living by each run of the GFS model beyond a week. I would suggest looking at as many forecast models as possible, and especially the ensemble mean runs of the models that are averaging dozens of ensemble member runs together. That will take out a lot of the run to run inconsistencies and give a better idea of the potential pattern and potential for increased or decreased precipitation chances. The GFS will constantly find and lose storms beyond a week while the ensemble mean runs could continue to show precipitation over CA and will show the totals increasing or decreasing a little each run.

I will be on the Tahoe Today show on Lake Tahoe Television discussion all things weather with Coop, Wednesday morning at 8:30 a.m.