Breezy in Town and Windy over the upper elevations Wednesday but Dry….Slow warm up through Monday……Models Still Beating Westerlies Breakthrough Drum, Timing is toward the following weekend…..
Wednesday February 19, 2014
Posted at 8:10 am by Howard
Not much to add from yesterdays discussion. The global models all have pretty much the same scenario with a break through of the westerlies next Wednesday night supported by the eastward progressing MJO into Phase Space 8. The EC this morning has two important waves for consideration. One Wednesday night the 26th and the other Saturday night March 1st. This is from the 00z Thursday ECMWF deterministic run. This is the 1st time this winter that the MJO is likely to progress through Phase space 6 to 8. SEE: http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/ncpe.shtml
I think that those with a strong interest should read up on the MJO and how dynamically it supports the far extension of the EAJ to the west coast. I will post links when I have time on that matter.
It is clear to me that there were several opportunities for this extension to happen in this current winter. IE (The break through extending to the South Central West Coast, which failed because of the lack of support of the MJO. This time appears to be different, and thus there is a higher level of confidence to me from this distance in time. Follow the MJO here and look for any hesitation in its progress for hints of any future back peddling of the guidance.
Trying to make the case for a break through of the westerlies into California….
Although the forecast has been dry through the early part of next week. The longer range models of the ECMWF and GFS has been showing an extension of the East Asian Jet well into the Eastern Pacific. When this happens, one has to look at the Wheeler and Hendon Phase space to see what is happening with the MJO as well as discussion’s relating to that action. The fact that the models are making a transition based upon both the extension of the east Asian jet and heights building northward over the far eastern pacific and up over AK is not random. “There is a cause for effect” The latest discussion from the CPC clearly identifies the causes. The MJO is forecasted to strengthen and move eastward through phases 6, 7 then 8. “Given a persistent and largely coherent pattern of tropical convection over the next one to two weeks, some extratropical teleconnections are anticipated to become apparent. The reemergence of upper-level divergence over the West Pacific coupled with upper-level convergence over the Indian Ocean favors a reversal of the recently observed retraction of the East Asian jet stream over the next one to two weeks. This would favor lower geopotential heights in parts of the North Pacific, with downstream ridging over northwestern North America. Additionally…..There is a reasonable chance that tropical moisture becomes entrained in a low-level circulation near Hawaii, increasing odds of above-average rainfall in that region.
(As mentioned yesterday, watch for report of heavy rains over the Hawaiian Islands later this week. That can be a sign that precedes a wet event on the central west coast)
In the meantime, amplification out about 140west will build toward the Gulf of AK. At the same time, the upper ridge will become established again over the eastern pacific. This ridge will slowly progress into California, early next week.
Sensibly, we will note that it will be a cooler day today and breezy, as a short wave passes through Mammoth this morning. Heights will continue to rise out over the eastern pacific and so a NW flow will insure a cooler than normal weather pattern the next few days.
As the upper ridge continues to both amp and progress eastward into California the next 6 days, slow moderating temps will follow. Expect 5 to 7 degrees of warming between today and next Monday. Nighttime temps will dip into the teens, then rise to the 20s by Sunday.
By next Monday, if the westerlies are going to break through later next week, the hype will be in the media and my discussion will be but a memory……
Dr Howard and the Dweebs……………………………..:-)