Mild and dry weather will continue across California this week. Gusty winds will also increase the fire danger for Thursday and into Friday. NOAA has upped the chances for a La Niña pattern. The 10 most similar seasons have an average snowfall of 113%.
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Not much change in our weather this week as the fire season drags on and we are still choking on smoke. It's been about a month now of almost daily smoke-filled air.
There are plenty of fires surrounding us on 3 sides...
...and smoke is easily blowing into the basin no matter which way the wind blows. Here is a look at the current smoke map on OpenSummit.com/map:
You can view the above HRRR smoke forecast for the next 18 hours over on our OpenSummit app as well. It's awesome to have this smoke forecast data in an easy-to-view map on your phone.
Even an east wind will have to blow the smoke out that's sitting to the east in NV.
Unfortunately, we have the usual prevailing west/southwest wind in the forecast for the rest of the week. The temperatures have cooled into the 70s for highs at lake level so it's not as hot as the last several weeks, but the winds will be increasing later this week as a trough approaches the West Coast.
That will tighten the pressure gradient with increasing winds by Thursday into Friday. That will only increase the fire danger in the dry climate over CA. Here is a look at the Mt. Rose summit forecast from OpenSummit.com showing the winds, and the colder temperatures this week above 10k if you happen to be hiking. This is for the actual Mt. Rose the mountain, not the ski area, although it's right near it.
Some model runs over the last several days were showing the possibility that the system for the end of the week would dip far enough south to bring a few showers to the Sierra and Tahoe area. But the latest model runs keep the precipitation to our north. As of right now, it looks like just a dry wind event, unfortunately. The Pacific NW will pick up some light precipitation, hopefully at least enough to put down some of the fires and clean up the air a bit.
It will cool us down into the 60s for highs for Friday-Saturday before high pressure builds back in over the weekend and warms us back into the 70s going into next week.
The long-range models are pretty much all in agreement that a large trough could push into the northeast Pacific by the last week of September, around the 24th/25th.
That is pretty good agreement that far out especially during the change in the seasons. This is something to keep an eye on over the next 2 weeks. This is a large and cold trough that would push storms into the Pacific NW. We would be on the southern edge, but a small shift in the storm track to the south and we could get some much need precipitation?
The Canadian ensembles are the farthest south with precipitation this far out. Fingers crossed...
The long-range climate models have been hinting at a wetter October as we have discussed in earlier posts. The CFSv2 and other models like the European seasonal and weekly models show a wetter month in October, especially later in the month.
That map already looks similar to a La Nina pattern, but also an early-season pattern with the jet stream aimed to our north. Things can change fast around here later in October. We will be watching with anticipation for heavy rain and snow that could put a quick end to the fire season, at least for northern CA.
The Winter Season:
It's still too early to forecast the winter season, per my annual post talking about how you can't forecast a winter season this far out... But I am dreaming of a white winter after ours was stolen from us last season by the virus that I won't mention by name to not give it the infamy it craves. My new board showed up about one week before the closures...
So here my board and I sit, searching the historical charts and trying to line them up for a dreamy winter full of deep days... The kind that will be much-needed medicine to the soul.
I've done several posts already on the upcoming season. I usually don't post any kind of a winter forecast until later in October. But some early season ramblings to clear my head won't hurt, right? Anything to keep me from scrolling through my Twitter feed.
So what will 20/21 bring? No one really knows for certain. I'm still hesitant to share my musings this early. So please keep this between you and me, shhh.
NOAA has upped the chances for a La Nina pattern now to 75%. We have fairly cold water along the equator already, in the moderate La Nina range.
The current PDO (Pacific Decadal Oscillation) reading is slightly negative thanks to some colder water. But the vast majority of the northern Pacific is still warmer than average. I'm more interested in the warm water in the Indian Ocean into the Western Pacific and the blob of warmer water north of Hawaii. How does this setup compare to my favorite season?
Somewhat similar in those 3 regions, but it was colder from the West Coast back to Hawaii in September 2010. That was a strong La Nina season. I'd like to see that warm blob north/northwest of Hawaii and some colder water off the coast. The 16/17 season was a weak La Nina with the water warmer off the West Coast.
The current SST map looks like it's in between the two. Here is a look at a typical La Nina pattern.
Here is a look at the height pattern forecast by the CFSv2 and the JMA for Dec - Feb?
The CFSv2 has higher heights a little closer to the West Coast and the JMA in a more favorable position to the north/northwest of Hawaii. I'd keep an eye on the blob of warmer water as we go through the fall to see where it sets up, and if we see cooler water develop off the west coast.
I like the warmer water in the Indian Ocean to the western Pacific as we hope for an active MJO ( Madden Julian Oscillation) through that area this season. That combined with the positions of the mean ridge could mean the difference between a 10/11 or 16/17 season? Or a non-active MJO and the ridge closer to West Coast and another dry season?...
Adding in the PDO, QBO, and other factors, and looking back through the last 50 years, I look for years with similar conditions and assign scores. The highest score I'm getting right now is 1970/71 (119% of average snowfall). The 5 most similar seasons are giving me an average of 124% of average snowfall with only one season below average.
This is assuming we stay with a moderate La Nina. Downgrading to weak and looking at other patterns being similar to this season's forecast, we would add 5 seasons with 3 of 5 below average but one of those seasons being the 16/17 season with 141% of average snowfall, and the average of those 5 seasons at 103% of average. The average of the 10 most similar seasons I'm coming up with right now has an average of 113% of average.
So suffice to say that I'm optimistic for this season based on historical data vs the forecast for the pattern this season. The most optimistic since the 2010/11 season when I had a forecast for 125% of average snowfall and we ended up with 158% of average. I took a beating in gossip circles around town that fall, but that was the only season I went out on a limb like that in the last 10 years.
It's still too early to make a forecast. A lot can change going into the winter. Just unloading my musings for the week as I look forward to winter. But this is 2020 where nothing seems to go right... Maybe it will be a continuation of bad for those that hate snow and those who moved to Tahoe this summer to escape the city and have no idea what they are in for during a big season, and a change in luck for the rest of us! Only one type of person can have big snow be bad, not both if the ski resorts are open.
Speaking of which. A lot coming out about how the ski resorts will operate this season. Some with reservations, others without but limiting pass sales. It will be interesting to see how it works.
It will take a lot to keep me off the hill this season if the mountains are open and the snow is falling. But you will find me socially distanced in the side country or in the trees, as usual. Not a fan of crowds in any season. Prayers for those who have been affected, and praying we see a positive turn of events going forward, in many aspects. High hopes for this season, think positive, be kind to all.
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