Here’s the Lates Tahoe Weather Update:
The models have been showing the MJO looping around but it was looking weak and with it only being Sept. I wasn’t really all that concerned. But it is forecasting stronger now and it will pull the ridge back out to around 170w next week allowing a fairly strong low for this time of year to move in off the Pacific NW coast. That low is forecast to come onshore up there and then drag a strong cold front through our area. I’m always cautious this time of year about trusting the models because they can tend to make storms look stronger.
That being said the precip totals are quite impressive on the models today with over an inch of liquid. As the first surge of moisture arrives Tuesday night into Wednesday the snow levels will be above 8000 ft., and then they will fall all day on Wednesday. There is another surge of moisture on Wednesday night with the cold front and snow levels fall to lake level. At lake level we could see several inches if the front comes through at night, and above 8000 ft. on the peaks we could see up to a foot of snow. Stay tuned because we are still a week away, but lots of model agreement today increases confidence we will see at least some snow.
The MJO cycles through and then that’s it. It’s not the start of Winter yet and we should see a nice rebound in temps going into the 2nd weekend of Oct. as the ridge builds back in. I keep thinking this season should be a lot like 07-08, and we did see a quick shot of several inches of snow the first week of Oct. that year and then it was warm and dry into Dec. It got cold in December for snowmaking but we really didn’t get our first big snow until that superstorm the first week of January. I think we will see snow a little earlier this year and not quite the abrubt stop on March 1st as that season. I would expect some of those big cold storms dropping in from the Gulf of Alaska in the heart of Winter.
I know some of you have been waiting for one of these big posts and with some of the newspaper interviews this past week and now the storm next week I am really starting to get amped up for the coming season! I have more on the Winter forecast from some research this week. The ENSO update this week shows that the water continues to cool in the Eastern Pacific along the equator. Weak La Nina Conditions are present with temps 0.6-0.8 below average, but as of the end of Aug. the 3 month average was 0.0. You need the 3 month avg. to be at least -0.5 for 5 straigth months to be declared an official La Nina.
I keep getting distracted by these great baseball games that are on.
One thing that is different than last year is that at the end of August the 3 month avg. was already at -0.6. The later onset of La Nina and the continued warming of the water just off the coast should keep Winter at bay longer this year barring any more MJO activity in the Western Pacific. With a moderate La Nina though, and a warm AMO in the Atlantic we should see the jetstream stay pretty strong and consistent during the heart of the Winter diving down from the Gulf of Alaska into the Pacific NW as we are on the Southern Edge.
The thing that gave us the huge snow this past season was all the blocking that occured in the North Pacific & Canada. It gave us three times during the winter where the jetstream was suppressed South and aimed right at us for a week straight giving us 100+ inches of snow. That blocking can be attributed to the negative Arctic Oscillation we saw. I was reading some insights from Joe Bastardi on the upcoming Winter regarding the AO and he thinks we will see it go negative quite a bit again this Winter. That is a plus for us because that means we could see some blocking again this Winter. That could push my latest Winter forecast for just below average precip up closer to avgerage.
Also it is looking like we could have quite a cold Jan & Feb over the West which could take below average precip and turn it into above average snowfall as the cold air creates high snow:water ratios. AKA lots of POW! I am getting more confident that would could have a decent season with the La Nina conditions continuing to strengthen and the forecast for the AO to go negative. I think we are shorter on both ends of the Winter but without the 6 week drought in the middle.
I know I shouldn’t show you this but [above] is Joe Bastardi’s preliminary Winter forecast [map]. He lives on the East coast so I think his geography of the mountains is a little off and the dark blue should be over us. The light blue is 100% of average snowfall or better and the dark blue is 133% of average precip or better. This is only through March though, so like in 07/08 where we were above average as of March 1st we should then have a quicker end to Winter and below avg. snowfall in April & May that will average us out. Stay tuned……..BA