Tuesday, January 21, 2014

Why This Warm Winter Is Not a Good Thing!

LOS ANGELES - As the Midwest and East Coast freezes again Southern California is yet again the envy of the nation with its warm winter weather. However, as you have probably noticed much of this winter it has been unusually warm, even by Southern California winter standards. The dreaded Santa Ana Winds, which usually blow between late September and November, have been hanging around much longer than usual blowing havoc as evident by the recent destructive Glendora brush fire.

Brush fires aside many people have been enjoying this warm winter, but there is real cause for concern that this warm winter is not a blessing.

The reason being, according to Weather West, California is under what is being called the Ridiculously Resilient Ridge, or just RRR. Now it may have a ridiculous name, but the RRR is a very serious problem for California, because, simply put, it is preventing rain from coming into much of the state, and causing Santa Ana Wind events when typically there should be no major wind events.

According to Earth scientist Daniel Swain at Weather West,
[The] Ridiculously Resilient Ridge [is a] region of strong and incredibly persistent anomalous geopotential height ridging is centered over the Gulf of Alaska but extends across much of the northern and eastern Pacific Ocean, and has been a coherent and distinct feature of the large-scale atmospheric pattern for over a year (beginning in early December 2012). This persistent ridging has resulted in a flow pattern that has deflected existing Pacific storms well to the north of California and suppressed the development of other systems closer to the state. Persistent ridges that disrupt the prevailing westerly winds in the middle latitudes are often referred to as “blocking ridges” because of their propensity to impede and deflect typical atmospheric flow patterns, and the RRR is no exception.  

This has not been receiving the wide attention it should be receiving, but with Governor Jerry Brown recently declaring a drought emergency, and what is leading to be possibly the worst drought in California history, hopefully people will start receiving this warm winter weather with concern.

Now the RRR is nothing new, but the RRR in the last two years has been cause for concern.

As Mr. Swain goes on to report,

[The] RRR has behaved in a manner not typical of most North Pacific ridging events. Since December 2012, large geopotential height anomalies have been observed in approximately the same region of the North Pacific. While the spatial structure of the ridge itself has varied somewhat over that interval (and even broken down in a couple of instances), the RRR keeps re-building itself in essentially the same place each time an atmospheric event–such as a surge of low-latitude westerly winds with the potential to “undercut” the ridge or an invasion of a cold/high potential vorticity Arctic airmass with the potential to disrupt the anticyclonic circulation–might otherwise act to displace or collapse it. This resilience is extremely unusual, and I don’t find evidence that persistent North Pacific ridging of this magnitude spanning two consecutive winter seasons has occurred previously in the observational record. 
Full report from Weather West.

With state reservoir levels sinking and dry air with no rain in site this warm California winter is not a good thing that it may be made out to be, and in the end we could all end up paying for this in more ways than simply higher water bills.

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