An unsettled period is expected today through the weekend with light snowfall accumulations expected…..Snow levels will average above the Town of Mammoth……It looks quite Breezy to Windy Saturday/Night into Sunday AM…..
Wednesday November 19, 2014
Posted at 9:45 am by Howard
The Ridge Trof Pattern over the CONUS will continue through the Weekend with eastern pacific short waves (Areas of Rising Air) moving through the Mean ridge Position (Large N/S elongated area of sinking air) along the West Coast. In the meantime, the current Frigid Trof and cold air will flush east out over the northwest Atlantic and slightly open the wavelength of a slight weakening of the upper west coast ridge Thursday/Night. This will give us our best chance of precipitation which I think will be light at best. Possibly 3 to 6 inches over the crest. There are other systems that will be effected by this weakening upper ridge. So unsettled weather is expected through Sunday beginning as early as today. With that said, no major amounts of Snowfall are expected…best guess “About” 3 to 6 inches over the next 5 days.
Based upon the 21 day cycle…..Our hemispheric pattern goes into transition later next week. The big question is where is it going and if it will be a stable hemispheric pattern. ———–
For an understanding of the extended outlook, one has to look at the tropical Indian Ocean for organized areas of convection that are progressive.
During Warm ENSO years, the MJO becomes less coherent as it moves toward the Western and Central pacific as the Base State SSTA is generally Warm and so the MJO signal becomes more incoherent. With that said, there is usually plenty of definition over the Indian Ocean to the Maritime Continent.
The point here is that the Dweebs look toward the MJO for hints of a pattern change and what the pattern may be like.
Currently, The MJO is in the coherent base state wave I, which favors the current ridge in the west and a trof in the east. If a strong progressive signal is identified and is forecasted to progress through the Indian Ocean IE Phase III, that would have major implications for the CONUS. It would essentially flip the pattern to a warmer upper ridge over the SE and a West Coast Trof. and allow for an extension of the EAJ to the Central West Coast.
Here lies the Concern this Morning:
In reading the latest CPC discussion……It acknowledges that “A coherent Wave-1 upper level zonal wind anomaly structure exists” over the Western Hemisphere. Furthermore, Some of the Models…IE the ECMWF, UKME and JMAN all show a signal that is fairly strong into Phase III which is what we want for lots of snow out west by the end of the month or 1st part of Dec during later week 2. However, the American models namely the GFS (NCEP) shows it stalling on the border of Phases 2/3 and weakening. The key to all this is using and watching the Satellite pics over the Indian Ocean and looking for large concentrated amounts of Convection, (Lots of Thunderstorms) and organized areas of Sinking air (Areas of clear) that develop or do not develop over the Indian Ocean. That as well as the lower level flow pattern coming across Africa. In reading the paragraph below, one can certainly put doubt to the validity of the strength and forecasted locations of the MJO currently forecasted by the 3 models aforementioned above.
Below is a transcript of the latest tropical discussion from NCEP on the developments over the Indian Ocean.
A more coherent MJO signal was evident during the previous week, with the RMM Index indicating that the enhanced phase propagated across the Western Hemisphere to the far western Indian Ocean. A coherent Wave-1 upper level zonal wind anomaly structure exists, with equatorial easterly (westerly) anomalies present across the central and eastern Pacific (South America through the Maritime Continent). The low-level wind field is less coherent over the Indian Ocean, and while the upper-level velocity potential pattern continues to exhibit a Wave-1 structure, the anomaly field has weakened during the past several days. Despite the fairly robust MJO signal indicated by the indices, “equatorial convection has been weak across the Indian Ocean”, with localized areas of enhanced convection displaced from the equator. Anomalous low-level equatorial easterly anomalies across Africa may be helping to inhibit widespread convection, in addition to destructive interference from the base state that favors suppressed (enhanced) convection across the Maritime Continent (western and central Pacific).
The Upshot of this paragraph states that there is little confidence yesterday of the Idea fostered by the 3 models mentioned earlier, trending the MJO strongly into Phase III. For that matter, the long-range guidance The ECMWF EPS is connected to the MJO INDEX Forecasts as well. Meaning that if the MJO index forecasts do not validate, the long-range guidance is currently wrong as well.
The Forecasts for all that QPF will not likely materialize in November, partially because the data was garbage…..
The Eastern Half of the CONUS is in Trouble……
Dr Howard and the Dweebs………………….:-)