Current Episode of Moist SE flow to begin diminishing by Friday leading to a fair warm weekend……In the meantime, High Country Showers and Thunderstorms possible, shifting a bit east Thursday…Then Dry Friday through Sunday
Tuesday July 8, 2014
Posted at 10:52 am by Howard
There has been a nice moist SE flow pattern over the Sierra the past few days…however little in the way of a trigger for heavy rain until today…Today looks to be the best day for some substantial rain over Mono County….With POPs as high as a 60% Chance!
Scattered Thunderstorms will redevelop Wednesday…..However, without as big a trigger as today. Nevertheless, storms may form again and areas of heavy rain possible tomorrow. A weak trof of low pressure will begin to back the upper flow from the SSW Friday with even more SW flow Friday night into Saturday. The weekend looks fair and warm with highs returning to the low 80s by Sunday.
Outlook for next week:
The Subtropical upper high builds back into California by Sunday and remains the dominant feature next week. A combination of light flow aloft and daytime heating will result in the typical air mass thunderstorms with forcing mainly the typical high elevated heat source of the Sierra in addition to the usual surface convergence that is moves about on a diurnal bases. At this point, I do not see another Strong SE flow set up….that is not to say that one could not develop between today’s model runs and the end of the weeks runs for next week.
The latest numbers for the Nino 3.4 and 4 region are pretty anemic. The very strong Kelvin wave that moved across the pacific has run its course. This is at least, part of the system that created the very warm SSTA’s, South East from Pt. Conception to San Diego where sea surface temps are as high as 78 degrees off the San Diego Coast and positive SSTAs are also found south along the Baja Coast.
The latest weekly Nino data shows that during the time period of June 25th through July 2nd, all Nino regions of the Nino Basin have cooled with the exception of Nino Region #3. This was a direct result of the rear upwelling phase of the Kelvin Wave. As of late, a new but weaker Kelvin Wave is beginning to increase the sub surface temps and thus making an effort to renew the heat in the NINO basin over the next few months. The Down Welling phase in its nose is warming the subsurface heat content at longitudes of 160 East to 180 West.
At this Time…it is the opinion of the Dweebs that it is highly unlikely that we will have a “Super Nino”, one which SSTA’s are at, or above +2C in the Nino 3.4 region. However, even a weak El Nino (.05C) can bring a normal amount of Precipitation to Southern CA and a winter that is 80% to 90% of normal to the Central Sierra Crest. There are a lot of Split flow systems in a Weak El Nino and so coastal areas of Central and Northern CA can get a lot of rain while interior sections can get much less.
There is no real way to predict with much certainty what the winter will be like until the Early Fall, as by then, well have a better idea on how the Nino regions are doing heat wise as well as the other teleconnections that will be effecting the weather for the upcoming winter. One thing is known at this time….The PDO is positive and the QBO is negative which argues for another cold winter east of the Divide. The big question will be…Will the stronger than normal subtropical upper jet be strong enough to flush out the cold air from the Hudson Bay > east out over the Atlantic next winter…..
Dr Howard and the Dweebs…………………………….:-)