Long Awaited El Nino/MJO Forced Storm Cycle has finally Developed after a 6 months wait………Southern Stream energy gets ready to deliver……
Monday January 4, 2016
Posted at 6:50 am by Howard
WINTER WEATHER ADVISORY IS IN EFFECT FROM 10:00 AM WEDNESDAY MORNING THROUGH
4:00AM THURSDAY…… AREAS ALONG HIGHWAY 395 SOUTH OF MONO LAKE MAY EXPERIENCE
WINTER STORM WARNING CRITERIA INTO EARLY THURSDAY AM….
Some interesting possibilities for week two. (Wednesday through Tuesday the 20th).
The Dweebs are looking at both the MJO phase space forecasts from the GFS (American Model) and ECMWF (EURO) Model
The GFS has the MJO doing circles between Phase 7 and 8 and the ECMWF has it progressive into Phase 1 and 2.
Look at these:
It would be unusual for the MJO to get stuck in Phase 7/8….So week two in the GFS is probably out to lunch
However it is interesting to see what a phase 7/8 does to the pattern week two. The 12zGFS shows it being very wet for California with a possible very nasty Pineapple Connection to the west coast. Again this is not likely…..
The ECMWF would support more splitting of California systems early next week and I think that is the more likely scenario…
Will see if there is a compromise somewhere….
Tuesday 11:00 AM
Our 1st significant storm of the new pattern is into the Sierra and most of California at the moment. Up to 8 inches of rain is forecasted for parts of Southern Ca over the next few days and some 3 to 4 feet of snow expected for Mammoth Mt between the two storms. IE. todays and Wednesday/Thursdays. The Dweebs have been touting all this for two weeks now and will now shift gears and focus on the bigger picture and longer range as the current pattern is old news, although to some extent….Unrealized….
In yesterdays early AM discussion, I made a big point of what we can expect from the current southern stream and what happens in the east will affect the far west. What is interesting about the current pattern over the Pacific is that all teleconnections seem to be moving along quite well.
- Very strong negative SOI…Providing that tropical support to the overall January warm ENSO pattern
- Strong Negative phase AO Anomalous positive heights over the polar region, initiated by the strong MJO recently
- Strong Negative Phase EPO Anomalous positive height anomaly in the far north GOA and AK.
- Strong Positive PNA (Anomalous Positive Height anomaly over Western Canada N/S
Everything is working well together!
However, the only fly in the ointment is the occasional trof in the east. This will impact the west coast ridge and cause the southern branch to split to the south or consolidate to the north. What is coming up in our future is classic of that!!
The Thursday storm as it pushes east to the US mid section will phase with a system dropping put of South Central Canada. This will provide for a fairly deep cold low over the Ohio Basin south. While it is travels east, the far west will ridge up and deflect any major storminess from California.
The Southern Stream related to El Nino will come to the rescue and flush the cold system out over the Atlantic so that we may be able to get storms again later next week…. If by chance this cold system gets reinforced…our break in the pattern will last longer…
Eastern CONUS Cold Air Aloft = A Trof or large scale storm in the east. These systems often times become a thermal anchor, as in years past, a stormy east causes a warm dry west. With El Niño’s associated strong southern stream, any Trof that does set up in the East this Winter will likely be progressive. This is because the Subtropical will flush it out off the east coast. During most winters it becomes a fixture and California can go weeks or even months without a storm…
Some light snowfall this afternoon but nothing measurable in town…
As expected this first storm split and went south into Baja. Some areas of moderate rain reported this morning in the LA Area.
The next system moving in will be a better precip producer as the system will not split nearly as much. 1 to 2 feet is still expected for the Tuesday PM storm.
Storm # 3 looks the best right now with another 1 to 2 feet possible between later Wednesday AM and Thursday AM.
A smaller system is expected over the weekend.
Beyond the weekend there was some major changes in both deterministic model runs of the GFS and EC. They involve a rather cold system that drops down from Canada and phases with Thursdays storm later in the week over the east central US. Not too sure what to think of a big storm for the east now when it was not there yesterday….. Note a cold storm in the east could possibly put the KABASH on a wet week 2 for California. Well see how it all shakes out in a day or two.
It seems like its been a long wait but its January now and its show time For El Nino…….
I. I think that it is important to keep a perspective of what the biggest issues that the global models will be dealing with over the next several months:
- For the most part, El Nino forces a positive phase to the Pacific North American Circulation pattern. (Acronym) (PNA) (Anomalous heights aloft over Western Canada and Eastern Alaska)
a. The frustrations of many waiting for the southern stream to arrive were based upon the fact that the PNA was negative and thus the Pacific Northwest was wet and it was drier the further south you went down the west coast.
b. Now the PNA is positive and there is a formidable block in the PNA region that helps split the upper jet, sending more energy into the west coast from the lower mid latitude’s.
- Currently, the (MJO) The Madden Julian Oscillation is exceptionally robust for a strong El Nino and is constructively interfering with the El Nino Base State over the Central Pacific. Forecasts a week ago showed this convective envelope traveling from the Indian Ocean/Western Pacific eastward to the Central Pacific. Forecasts have subsequently grows stronger with this system. Readings in the SOI went from +30 indicating strong convection north of Australia during the convective phase of MJO to -33 as the SOI crashed due to the reactive suppressed state of MJO. Strong westerly winds have resumed along the equator between Darwin and Tahiti. As indicated by MET; J. Bastardi, this acts as a cattle prod to the atmosphere. SEE: http://www.cpc.noaa.gov/products/precip/CWlink/MJO/CLIVAR/ncpe.shtml
- Another Important teleconnection to a wet California in January, according to composites, is a Negative Phase (-AO) in combination with a +PNA, MJO strongly into Phase 7/8. You may have heard that the north pole is very warm. This is due to the Arctic Oscillation going strongly negative by which higher heights are dominating the Northern Hemi Polar region, and forcing lower heights along with an upper jet displaced anomalously south.
II. Had a nice conversation with retired WSFO-RNO Lead, T.C over the weekend. It was agreed that what will be important this winter is to watch what happens over the Eastern CONUS. Those watching the global models the past week may have noticed the flip- flopping of the west coast systems and how much QPF they are painting. They are reacting to what is happening downstream over the east. The key in any warm ENSO pattern is how strong/persistent the subtropical jet is, as it travels from BAJA through Texas, and parts of the south, then veers strongly North East. This needs to happen continuously so the cold air from Canada can get flushed out over the Atlantic. As if it gets bottled up for some time, that can weaken the incoming storms, split the west coast upper flow or if the cold air gets entrenched, ridge the west coast up in a full Latitude block. At this time we have “Constructive Interference” in the El NINO base state with a strong robust MJO. The Subtropical jet is likely to remain strong for several days to come.
So from a Forecast/Outlook point of view, the storm track is now set up for a series of storms this week with a break then another series that will likely last a week or two. The wave length between the east and west coast will be key to how much snowfall gets east of the Sierra Crest. The trend will be for warmer and wetter storms week 2, as heights rise a bit along the west coast in reaction to the MJO shifting east. This in turn forces a long wave trof or (Adjustment Wave) to deepen over the EAST-PAC as the upper flow becomes SW from the Tropics/subtropics . Remember the MJO helps to modulate the westerlies and so its phase state will need to be watched, for the purposes of predicting the retraction or extension in the East Asian Jet to the west coast in weeks 2 and 3.
The Forecast is for snowfall most days this week with moderate to possibly heavy amounts. The Dweebs forecast between 1 and 2 feet by Wednesday AM. Although there are more systems likely into the weekend…A Big Question this morning is….Will the Tuesday Afternoon/Night storm be the biggest or will it be the Wednesday night storm? Clue…..A lot depends on what happens in the east…….;-)