Friday AM Update:

Just has a peak at both the 00Z Friday EC and 06Z GFS:

Some interesting deterministic run possibilities….

Both Models continue the trend of the Blocking pattern with ridge in the west. And continuing their trend of the possibility of a bit more moisture for the weekend (Sunday) system for Mono County. I think that I covered it well in the late Thursday afternoon update below.

A new twist though showing up from last night 06z GFS run with some hang back energy underneath the building ridge early next week from the Sunday system. The GFS has this weak low left over or near Southern CA that may just provide an off shore flow and a warm up for LA. However, the ECMWF has a bit more energy that follows the Sunday system early next week that spins up a small closed low on its drack south then off the coast of Paso Robles, CA. That would dampens LA’s warm up and actually put Mammoth in the upper Divergent NE quad of that system, providing some light snow or snow showers anytime between late Monday afternoon and Tuesday night. The system does track south off the SO-Cal coast and so the off shore flow is probably just delayed in this case.  An important point to make is that this all happens as the upstream building ridge that will eventually take over the west coast, later Wednesday into Thursday.

Some New Twists to the longer range:

Earlier in the week I mentioned that the ridge that will be building next week will be top-heavy. This means that a lot more high pressure aloft (Anomalous higher heights) will develop over the higher Latts, and eventually over AK.  +(PNA) & (-EPO). That in its-self reinforces the pattern that has the potential to deliver very cold weather to the Ohio Valley and south to the Gulf States in the 6 to 10 day period. The EPS, AO has that teleconnection dropping to -3.5 standard deviations of normal, meaning that this Block has legs and will likely hold through the 10 or 12th of Dec. However, both EC and GFS are showing some changes there after as the AO goes to 0 (neutral) by the 18th. The WPO area (Bering Sea) has increasing heights at 500MB between the 14th and 18th of Dec. This is signaling a change with the possibility of retrogression of the upper west coast block allowing CPK air (continental polar) air mass to back up over the far west. (Cold)  More later…….

 

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I Just looked at the last few runs of the GFS and EC (American models) and Euro for the weekend. The Trof that is forecasted to come through this weekend is holding on to a WSW flow better in the GFS as compared to the ECMWF.  This is being reflected in the Models QPF.  The EC just brings us a dusting while the GFS suggests possibly 4 to 5 inches of snow over the crest, out of .3 to .4 inches of water.  The 18z GFS is showing higher QPF amounts as compared to its previous runs.  What ever we do get, the ratios of snow to water is going to be pretty high. Possibly 13 to 1.  So some light powder to begin the new week. This will be a windy system for the upper elevations and breezy for the resort levels. It will also be a cold system with temps at 700MB (10K) lowering to -8c to -10C on Sunday. Not all that unusual for early December.

Long Range:

I have beaten this dead horse enough so I will leave it alone for a while and concentrate on the Inter-seasonal outlook.

Today the ECMWF EPS 46 day weekly’s has updated. All I will say for now is that its long-range teleconnections are encouraging!

Here is a brief summery of what I have found out.

  1. The Current negative phase of the Arctic Oscillation turns Positive after the 18th of December and trends more than 4 standard deviation’s above normal by January 7th. So Lower pressure develops over the Arctic which can lead to a more progressive flow across the CONUS. (US) At the moment we are headed toward a very blocky pattern across the CONUS next week with a -AO. This is usually dry for California in a La Nina.
  2. In the same time frame, “Early January to mid Jan, the EP turns very negative, meaning a strong block over Alaska. A strong block over AK with a -AO is dry for California. However, a +AO with a -EPO could be wet for the West coast. The PNA which is positive now will trend negative between Christmas and New years,  while the WPO become negative IE (Blocking over the Bering Sea), toward the end of the year. This suggests Trofing along the west coast toward year end, and a block over the Bering Sea could be a wet west coast pattern. These teleconnection patterns work together and offer various solutions.  My sense is that we will begin to turn stormy around Christmas with several  period’s of snowfall up to about mid of January.  I am just using teleconnections, but that is all I have to work with at this time.

Dr Howard and the Dweebs………………….:-)