Last Storm of 2015 to move in Monday morning with 1 to 3 inches of snow in town by Tuesday and 3 to 5 inches over the upper elevations…..This system will bring more cold snow to the high country and leave another Chilly Air-Mass in its wake….After a break in the action Wednesday through the News Years weekend…Long awaited ENSO/MJO induced Southern Stream energy sets up for Southern California during the first week of January as the pacific NW goes dry…..
Sunday December 27, 2015
Posted at 2:25 pm by Howard
Note: Both EC and GFS are flirting with a westward digging small feature from the Great Basin forming a Tonopah Low & synoptic scale (REX BLOCK) over the New Years Holiday “Weekend”……This is something that will have to be watched. Although the current forecast does not reflect any precip for the holiday weekend….it is not set in stone.
Interesting to note that the SOI (Southern Oscillation Index) has become strongly negative again. This is testament to the fact that the enhanced convective state of the MJO has now passed the Maritime Continent and now the suppressed convective state has arrived over that region. What is noteworthy is that the SOI was very positive at +30 just two days ago and now -20. This is a strong MJO and it is holding together surprisingly well, considering the EL Nino Base state. The global models are all singing the same tune that a wet undercutting of the westerlies will occur early next week and bring Southern CA a lot of rain. Although several comments were made this morning by the WSFO Dweebs related to the fact that this it is a long way off… The overwhelming support in the models for the break through, is additionally supported by both the strength of the MJO, its effect upon the SOI , and its forecasted track through Phase 8. Checking the long-range QPF in the ECMWF, it still showed between 3 and 4 inches of rain for the coastal mountains of Southern California between the Monday following New Years Weekend and the following Wednesday.
One more comment to the above, is that if it is cold enough over the Owens Valley when this southern stream energy comes in and rides over the top of the colder surface…..that is a potential recipe for snow in the Owens Valley…There is good Climo-Support for that historically….
Although we have a small storm tomorrow Monday that will freshen up the base, there are more important changes on the horizon. Changes that will likely bring long awaited beneficial rainfall to Southern CA during the first week of January. Those Angelino’s that have been patient, congratulations. Many have given up hope for the kind of rainfall that will begin to make a difference in the current drought.
It should be pointed out that strong MJO’s that constructively interfere with strong El Nino base states are unusual. But this strong El Nino is quite different than other very strong episode’s. The distribution of the heat over the NINO basin is different. The SOI has acted differently and now we have a strong MJO that apparently will constructively interfere with the El Nino’ base state. It will be interesting to watch the global models and how they handle the upcoming events during weeks 2 and 3. IE the 3rd of January though the 17th. For the latest MJO Phase Space See: http://www.cpc.noaa.gov/products/precip/CWlink/MJO/CLIVAR/ECMF_phase_MANOM_51m_full.gif Phase 8 is often times where we get “AR” events, mostly during weak La Nina’s…
In the months of January, February and March, the strength of this MJO forecasted in phase spaces (late 7), 8, and even 1 are enough to suggest an AR event of some kind for California, with or out ENSO.
The models now are all pretty classic in bringing on the positive PNA 1st later next week, then a break trough of the westerlies during the first calendar week of January. The long range models indicate that heavy precipitation is probable for Southern CA in the outlook period of week 2 and beyond.
However, while it is always fun to watch the 500M Progs, it is going to be just as interesting looking at how deep the surface lows will get off the Southern and Central CA coast and the winds that will be generated from them….. 850MB RH and 700MB RH maps for moisture flux and of course 300mb for the best upper divergence….
This afternoons 6 to 10 day and 8 to 14 day NCEP outlook maps puts the focus on Southern California with the highest POPs….. And like what you would expect from a strong El Nino….The Dweebs expect a flip in the pattern, that has been with us for the past 6 plus weeks, where it has been wettest to our north and drier as you go south. As we begin in January, the heaviest rainfall will be in the opposite place where it will be wetter over Southern CA and drier as you go north. This may not be permanent, but a good part of January will develop this way.
When does it all begin? According to today Sunday, the 27th, The 12Z ECMWF has it beginning as early the Monday following News Years…… This is much faster than earlier outlooks…but that is why it is an outlook and not a forecast yet…..meaning it is subject to change. The model is suggesting 4 to 5 inches of rain in the hills above Malibu between Monday the 4th and Wednesdays the 6th from just todays run. Again this is not a forecast, but an outlook because this is quite a ways out time wise. Both the intensity and location of the main precip can and will vary.
Unfortunately, the Central and most of the Southern Sierra is north of the storm as the bulk of the precipitation is mainly from Kern County south…. Again as of today…..so that can change to!
Dr Howard and the Dweebs…………………..:-)