Archive for November, 2016

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…….

Fair weather days to continue through the weekend with some cooling Saturday….Pattern change underway this weekend with light to moderate snow probable Wednesday….

 

 

Here is a brief update on the changes expected next week over the western hemisphere due to tropical forcing over the Western and Central Pacific.. The big news this morning is that the pattern changes touted by the MJO RIMM the end of October, are making their way into the week 2 global models (Next Week). Only now 6 days out, the models are showing the transition to an active pattern whereby cold, wind and snow returns to the high country, by early Wednesday.  From what I can see, the Dweeb Report was the only media calling for this change on November 1st report. So here we are 6 days out from a good possibility of cold, wind and snowfall. The storm being touted by all global models for next Wednesday is pretty average. Meaning that it is a classic short wave that will be progressive and move through Northern and Central CA Midweek. The part that make this short wave more promising is that it is being supported by the MJO “Madden Julian Oscillation”  In phase space 8/1. So I am going out and saying that I have high confidence in this weather system for very late Tuesday/Wednesday, and that it will bring light to moderate snowfall (Some where between 6 to 18 inches) to Mammoth Mt. At this time, there isn’t any subtropical tap so the upper Jet will do the forcing with terrain enhancement as well. Beyond Wednesday, the next possible system in the cards is for the following week.  I am not as confident in its timing, other than it will be sometime the following week. This 2nd system is more likely to split or get cut off from the westerlies. This opens the door to lots of possibilities for both timing and amounts of precipitation and its trajectory.  It may be that the storm cuts off and waits for the next upstream kicker to give it the boot.   I will update on the next system early next week via my letter.

For those that are interested, the Global Forecast System was touting 12 to 24 inches of snowfall for the Sierra by Thanksgiving yesterday Wednesday….”Caveat Emptor” “This is an outlook, subject to change.” 😉

 

Dr Howard and the Dweebs……………………:-)