December will be one to remember and will likely finish off on a dry note with mild temps in the Central Sierra and Partly Cloudy Skies……Changes still offered in the Climate models for the Far West By Mid January….
Tuesday December 27, 2011
Posted at 10:06 am by Howard
Dec 31…Happy New Year.
Latest 12z Run shows the January 6/7 short wave an inside slider now…..so the system is not likely to bring much more then snow showers and cooling……Still waiting for Mid Jan change to get into shorter term for better resolution…
The Dweeber…… 😕
Mid month pattern change still on with more and more ensembles singing the same tune……..Saving Grace……..
The only item to add to the bullet points below is that the MJO by some of the models, moves into a more favorable position for Amplification then Retrogression of the large scale features that one would hope for to give us a significant storm. In “Fantisy Land” (beyond day 10 of the GFS) there is a powerful upper low in today’s 12z run that moves off Asia about the 9th/10th, that pumps up a major ridge at the dateline which becomes closed off north of Hawaii over the Aleutians. The down stream upper flow then carves out a full latitude trof about the 12th/14th of January. Normally, it would be nice and exciting for the Dweeb’s to see something like this in the models, then get up and go about the rest the day. However, the Climate Models have been touting a change about the middle of January for quite a while now. So, coupled with the MJO, this Dweeb can not rule out this possible change. Furthermore, the extended runs of the GFS has been hinting at something involving a closed upper high near AK during the second week of January on and off of several runs now. If she exists…..I’ll call her “Saving Grace”.
Quick Update For Dec 28th:
No change in the short term with windy conditions Friday with some cooling Friday into Saturday…
Warm air advection showing up again around the 6th. New 12z ECMWF has quite the subtropical glob with a split trof or closed low showing up as well with the GFS. We might get some small amounts of Snow on the 6th/7th.
Might be interresting to see how split off trof combines with mid lattitude trof for the possibility of precip for Southern Ca and Central Ca. (Note) This is not any of the forecasts at the moment. Will watch…wait and see……
Pattern Changes still in the offering by Mid month…..Strong Northwest slider possible with strong winds and cooling….precip still questionable…PNA may become more positive later in the month of Jan we’ll see….
The Forecast for the East Central Sierra through the end of the year is for the current pattern of mild and dry weather to persist, according to the short and medium range guidance as well as the outlook models. The current mid latitude blocking pattern is likely to continue through the first week of January as well. On a teleconnection note, the Arctic oscillation (AO) will remain quite positive.
Beyond the New Year….there is some evidence that the WX systems moving into the pacific NW will become wetter with time and that Mammoth will get into a warm advection pattern sometime between January 3rd and the 8th. Again today, a good sub/tropical tap is developing in the guidance that puts some real juice into the systems from the ITZ later in the first week of January. There is decent climo support for this kind of pattern beyond the new year. This may result in higher elevation snowfall or ??? What ever it is….Any precip falling would be non dynamic and warm air advection driven at best. Updates later>>>>>
Currently, the latest climate model guidance, (Beyond week 2) which the Dweebs have to say are experimental at best, are still touting a change to a colder and some what wetter pattern beginning between the 10th of January and the 16th and again in the 17th through the 23rd time frame. A glance at the 500mb height anomalies then would suggest a return to a colder then normal pattern with the likelihood of snowfall for the Eastern Sierra. However with that said, it suggests that the mean trof position based on the position of the 500mb anomalies, would be a return to a similar pattern earlier this month with the suggestion that a broader trof might develop with somewhat better over water trajectory. What we need is for the mean trof position to develop about 130W with the upper jet coming into South-Central Ca.
The latest Climate Model data might suggests a mean trof position for that time frame east of 120west for a return to cold weather here in the Eastern Sierra and the possibility of occasional moderate precip producing storms. Essentially, the storms would once again develop and move from the NW and track southeast from the long wave ridge position some where just west of 140W which is a drier trajectory then rounding the base of a long wave trof off shore, and coming at us from the southwest or west. There is a lot of time before such a change occurs. Again, this type of an outlook is very preliminary and based upon experimental climate models……There are not forecasts or even officially outlooks. However, there would seem to be some skill there or the CPC would not bother with it. More later…….
Reference Glossary of Weather Terms
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