Tuesday AM:

It is another clear cold morning here in the Eastern Sierra. As the western ridge continues to build over the entire west coast and even up into Canada, a strengthening cold surface high over the Great Basin with a general off shore flow pattern is expected to prevail for several days.  Air Quality will diminish and those who live in the Eastern Sierra. We will note hazy conditions both day and night. This new pattern initiates with a strong east-west Gradient Aloft. Gusty easterly winds over the Sierra Crest will slowly diminish over time. Mammoth Mt was reporting easterly gusts in the 70mph range this AM. Again, winds will gradually diminish over the upper elevations as the gradient relaxes. At the Same time, warming aloft will begin today with the freezing Level expected to go up beyond 11,000 by tomorrow Wednesday. It stays there pretty much through the weekend.

This pattern over the far west is part of the infamous positive phase of the Pacific North American (+PNA). Its key teleconnection lies over BC, Canada were it is anchored. When teamed up with a strong negative phase of the Arctic Oscillation (-AO) (Anomalous high heights over the Arctic) This pattern along with a northern hemispheric four wave, (long wave pattern) is very stable and unlikely to change anytime soon. The Climate Anomalies from todays run (DEC 5th) of the CFSv2, Shows a 500mb positive height anomaly remaining anchored over the far west for both week’s 1 and 2, or through the 18th of December.  During week 1, the 500mb Height anomalies axis is located about 120west or over the Sierra. During week 2 it may shift east to about 110 west.  This eastward shift may bring further warming to the Owens Valley as there maybe periods southerly flow. By week 3 the interseasonal climate model shifts the northern part of the upper height anomaly over Canada further east to about 100West away from the PNA region, while the southern portion of the block remains strong over the Desert Southwest. This change will allow the westerlies to move back into the west coast from about Northern CA northward to Washington State. So the potential of an “AR” exists for the coastal regions of the PACIFIC Northwest. It would be primarily warm air advection precipitation over Northern CA, and most likely rain except for the highest elevations.

Based upon this mornings run, most of it remains to our north and that may be a good thing!  The week 4,  500MB height anomaly if we choose to believe it, definitely shows the Break Down of the +PNA pattern over the far west and SW Canada. So the pattern goes into transition, the last week of December.  Yesterdays European EPS PNA region showed the +PNA dropping to neutral by the 28th of December. What is even more encouraging is that the Western Pacific Oscillation goes negative about the Frist of January and the Eastern Pacific Oscillation goes negative beginning the first week of January as well. There two Teleconnections indicate that high pressure aloft blocking will develop between Alaska and the Bering Sea the first week of January and into the 2nd week. Just using these teleconnections along with a negative PNA, that tells the Dweebs that a stormy period will take place beginning sometime toward the end of the month of December and most likely into the first half of January. Of course, the Dweebs will have better visibility in about 1 to 2 weeks.


Stay Tuned……………………..>>>>


Dr Howard and the Dweebs………………..:-)





Monday AM:

It is a beautiful morning in Mammoth with clear skies and cold temperatures…..10 degrees at the village!  Last little wave of the westerlies is currently moving through, resulting in a reinforcing shot of cold air. Mammoth Mt will be making snow today and tonight and  for the next 24 to 36 hours.  The aforementioned wave will increase easterly winds later today over the crest while the lower slopes will experience light winds. Winds over the crest will increase to 80MPH by tonight out of the East.  This little ripple is the last shot of cold air before the full latitude ridge sets up. This ridge has legs and will likely last for at least one to two weeks. The Upper Ridge will shift slightly east week 2 and that will allow the beginnings of some southerly flow to boost temps up in the Owens Valley next week. The Climate models (CFS) shifts the mean ridge position a bit more east weeks 3 and 4. However, 500MB heights remain pretty high over the Christmas holiday period.  I would suspect that we’ll see some AR precipitation beginning later during the 3rd week of December into the end of the year. The Dweebs note that in todays interseasonal Climate Models run, our air mass will be warmer than normal and that high elevation snow would be the more likely scenario, if we have precipitation during week 3 and possibly week 4. The CFS also suggests the absence of any blocking upper height anomalies over or near Alaska during weeks 3 and 4; IE -epo or -wpo. That is inconsistent with the EU EPS that came out a few days ago as it touted different teleconnections.

I will update “on the EPS”,  later this week to see if there are changes to its teleconnections in the WPO and EPO regions.


Some thoughts this morning……

  1. At the moment, there is no doubt that there will be plenty of Great Lake, Lake effect snows over the coming two weeks. The Dweebs are just not sure that based upon the precip anomalies forecasted by the CFS for the Ohio Valley and east, that significant snows will be accumulating in areas that there would be enough for the feed back necessary to anchor this pattern in the long run. Although that is certainly possible, it just remains to be seen. On the same thought, without the feed back, we could see this pattern break down quicker or at least gets some decent storminess in here for a while.
  2. The pattern shift suggested by the CFS this morning would allow for a significant AR into California after Mid Month. However,  odds are it would be warm with high snow levels as there does not appear to be any cold air confluence with this interseasonal pattern shift, at least based upon this mornings look.  On a bright note, Mammoth Mt usually does much better for snowfall from AR events as compared to Tahoe, because of its elevation….:-)

Sensible weather:

Expect a couple of cold days, with warmer weather the second half of this week. Daytime highs will go from near 30s today and mid to upper 30s Tuesday,  to highs up into the 50s during the day by Thursday and into the weekend. The cold temps at night and early mornings as of late will moderate into the teens and 20s at the Village. By the weekend, expect lows in the 30s by Saturday.  It will be much colder over the lower elevations of town during the early AM hours the 2nd half of this week. IE Strong Temperature Inversions and diminishing air quality is likely!


More later after the new EPS is released this week….


Dr Howard and the Dweebs……………….:-)