Split flow blues to have silver linning as split delayed allowing decient moisture to arrive Sunday…..Thanksgiving Turkeys to gobbeling in the snow this season with more on the way afterwards….

 

5:30PM

Split flow taking its toll but active area to our west still expected to move east……North/South orientated Precip band is from about June Lake north with a fairly active area over Madera to the west. We may still get a few inches out of it so hold on….  As mentioned in earlier post…Split flow patterns are difficult to forecast……..

Next system is expected for Wednesday…although it is not splitting it is going to be mostly to our north.

 

More in letter issued later…

 

The Dweeber………………:-)

 

Sunday 1:25PM

 

Our splitting system still on the way and taking its good sweet time. Snow fall should begin about 6:00PM with very light amounts.  Thereafter, precip rates will pick up later this evening….  Amounts should be in the 4 to 8 inches class over the upper elevations with 2 to 4 in town by morning…

Next system Monday…..

 

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Fellow Dweebs, Dr Howard just had a total knee replacement Thursday AM so please pardon me if I do not share the current developing patterns enthusiasm as often as I would like to. With that said, the weather letter will always be on time with the help of Cyber K.

Looking at the ECMWF Ensembles, both Control and Ens Mean, it is evident that our current split flow pattern will consolidate toward the end of the month with a couple of good storms between about thanksgiving and Dec 1st.  There are timing issues of course this far out so I will not speculate on when the storms may arrive later next week, just that the long adjustment wave over the Eastern Pacific is coming into CA.  Also, as we go into December, the upper jet will become more NW orientated and so some of the storms will have lots of wind with them month end, into Dec. The best system in the series may be around Dec 4th.

The most current pressing system time wise is going to work out pretty week as the split comes in much later than earlier forecasted. This delay in split will allow some moderate snowfall to work into the Mammoth, Sunday morning through Sunday evening. This is not a cold storm. But will allow the snow levels to fall to 7000 feet during the latter half of the storm, then as low as 6000 feet about the time when the precip will be most over.  For the Snowplowers, and the guys itched to get out there, this looks like a late afternoon or evening plow when the storm is pretty much wrapped up. The upper mountain may get between 12 and 15 inches with the latter reserved for the very upper mountain as I see it. More may fall but as you know, split flow systems are sometimes the most difficult to forecast amounts…..The Town of Mammoth may get up to 6 inches at the village.  The next storm looks to be about Wednesday….more later.

I wanted to reiterate to all that the forecast of the change of pattern was picked up the latter part of October by the MJO phase space, and that is impressive from an inter seasonal point of view.

 

 

Cold Windy System Approaching West Coast Tonight….Highlights are wind and cold with light snow….Split flow pattern brings a lot of uncertanity to Sunday/Monday Storm….

Forecast remains the same as a windy system approaches tonight…..It will be a lot colder Wednesday and even colder Thursday because of the chilly NW jet on the Trof back side.  The current extension of the East Asian jet comes without much in the way of moisture for Central CA. The wave length between the eastern pac ridge (EPAC) and the ridge down stream is counter productive for the Sunday night storm. Thus the upper Trof being negative tilt will tend to split southward with the possibility of LA or even San Diego doing better with that storm. Some models have a more decisive split then others. So this is a case where any confidence in the numbers will have to wait until Thursday or Friday most likely. In that it is Mid November, Winter is beginning to set in hemispherically. So far winter has set in fully over Northern Europe and Northern Asia. In the next 3 weeks Winter will come to North America and our season of transition will be over.

The teleconnections all have the Arctic Oscillation rapidly going negative over the next two weeks.  This means that the upper flow will become more meridial in nature with high latitude blocking setting up with the westerlies undercutting here and their.  This eventually brings the cold south into the States. (CONUS)  So this is the question; Will the -AO favor the east or western US. I think both with the west first and then the east.  We’ll see.    As blocking develops, that should eventually take care of the problem of the west coast split.

I will have an update on Precip for the central sierra Thursday morning in my letter….:-)

 

For what ever it is worth….Those that are concerned about a good snowpack for Christmas might like to know that the 46 day, Day 0-46 or from 00z 14th of NOV to 00z Dec 30th; The ECMWF EPS ENS is showing a lot of snow for the Northern Sierra south through the bottom of the Southern Sierra with amounts of 150 inches suggested by the guidance.

Cooler temps will now prevail with a small system bringing light amounts of snowfall Tuesday night and Wednesday…..Next weather system timing is uncertain….

Yesterday afternoon the Dweebs were a bit confused about certain coincidences in the weather forecast charts across the pacific. For one, a vigorous trof was progged into Central Ca Wednesday, forecasting Light to Moderate amounts of snowfall over the Central Sierra. Two; While the energy coming off japan was showing to be very weak, without any real surface deepening until it passed 160 East. Today when the Dweebs looked at the latest Progs,  it all made sense. Strong digging upper waves need rapidly deepening surface cyclogenesis off the coast of japan at 140 East to support the continued digging of west coast systems.  So just like the MJO can give a higher level of confidence to week’s two and three outlooks, the support given to digging west coast short waves for both the timing of the energy coming through the west coast and how far a particular short wave will dig should be supported by Hovmoller’s connection of such systems and the propagation of energy across the pacific. In this case, the net result is that Wednesday’s short wave will move through quicker and the cyclonic side of its upper jet axis does not make it as far south as Southern Mono County. This will likely severely limit the amount of snowfall previously expected. IE 6 to 12 inches vs 2 to 4 inches over the upper elevations. The back side of the upper trof will dig into Mono County Thursday for windy weather and colder temps…Great of Snowmaking!  The next weather system will make its way into the Eastern Pacific the following week. The Dweebs will take a hard look at all the progs to see what may be the best scenario for short wave energy to come through the west coast with the western pacific timing tool next week…First in my news letter, then here publicly.

 

Dr Howard and the Dweeb…….