10-16-2022   10:40AM

Another brief update;

The idea yesterday that the MJO being in phase 6 with the Lagged composites’ showing a Cold Pacific NW to Great Basin LW Trough in Laggs 3, 4 and 5 seems to be favored again today.  The latest ensemble runs from both GFS and ECMWF continue to be in agreement in developing this Trof for the following week.. (Week 2)  So the pattern change that has been touted for next weekend still looks good.  Again the change, is to  colder, windy, showery weather here in the Central Sierra. It appears that there is another stronger Trof that will follow and deepen the western trough with a slight jog to the west. That occurs later the following week before All Hallows Eve. That system has the best chance of bringing significant snowfall to at least the Northern Sierra. This also is in agreement with the Lagged composites for later in October with tropical forcing in Phase 6.

While it is still too early to guess upon how much snow may fall that following week, amounts appear to be light in the Central Sierra with possibly up to moderate amounts in the North., The steep NNW track of the polar jet into the Great Basin. “initially” is usually drier for our area. The westerly Jog in the Jet for the 2nd short wave is encouraging for later Week 2.

The main message for folks that live in the Eastern Sierra…..Its time to get those last photos of the current beautiful foliage, as the possibility of strong winds developing by weeks end is increasing, and may strip the Aspens of their yellow and gold…. Also, there is the possibility of wide spread freezing overnight temps on the way for week 2.


Dr Howard and the Dweebs……………………….:-)






This is a brief update to our pattern change for the weekend of the 21st into following week.  It should be noted that the vast majority of Dynamic Models have the MJO in phase 6 for the foreseeable future. The MJO Lagged Composites for phase 6 during 2nd half of  October does have a cold trough over the Great Basin, consistent with the following weekend forecast into last week of October. So, there is additional support for global models in their week 2 Great Basin/Northern Rockies Weather system.


More later….


California and the West continues to be dominated by a mid-latitude blocking pattern. Little change sensibly is expected to our weather into early next week with some slight cooling by mid week. Highs in Mammoth have been running between 66 and 67 degrees and those temp are likely to continue through Sunday.  Lows at night have been in the mid to upper 30s. These high temps are some 5 to 10 degrees above normal for mid October. As the upper low off the Southern California coast kicks in Saturday, the upper flow over Mammoth out of the NE will lighten up even more.

Hemispherically, this weekend actually is part of the transition in the pattern that becomes more active Week 2. Here are the highlights of what’s to come;


  1. The Mid latitude blocking pattern (REX BLOCK) gets pushed eastward by a strengthening North Pacific Jet that sends a series of impulses into the ridge, off the coast of Washington State. Of course the little low off Southern CA moves inland as it is part of the block on Saturday into Sunday.
  2. This Sunday, a rather strong low move off Asia and spins up, and builds a down stream ridge that develops over the Central Pacific later next week. I believe that this central pacific ridge building is an integral part of the transition from the land mass heat source to the pacific as we transit from early fall pattern to more of a mid fall pattern.
  3. This Central Pacific Ridge is expected to develop further and especially during the last week of October.  Initially, the ridge has enough amplification to send a series of Northwest Sliders into the pacific NW as their rainy season begins as a result. Here in the Central Sierra, we will likely experience, windy weather, much cooler temperatures and the chance of showers anytime beginning about the 22nd or 23rd.
  4. The Central Pacific high gets more amplified the middle of that last week of October, while the westerlies dig systems further south toward the 27th. (Mammoth Included) This sets up as Great Basin/ Northern Rockies Trof in the mean.

As mentioned earlier and in past WX discussions, the timing of all this is subject to change….any direct effect on our areas weather from this pattern change will become more clear as we get closer to the last week of this month.


Dr Howard and the Dweebs…………………………….:-)