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…….;-)
Wednesday December 30, 2015
Posted at 12:26 pm by Howard
The weather over the next few days will be pretty quiet. The Dweebs expect colder than normal temps that will moderate a bit by the end of this week. Highs this week will vary between the 20s and 30s with lows in the single digits and teens for the most part. I am expecting dry weather through Sunday with no measurable snowfall. That may change by late Sunday night………….
The positive phase of the Pacific North American pattern is evolving. So we’ll have an upper height anomaly over Western Canada in the coming weeks. Additionally, the Negative Phase of the AO is forecast to develop next week along with the Negative phase of the Eastern Pacific Oscillation (-EPO). This combination will create more conflict with air masses and tighter pressure gradients. This is the last shoe to drop in the transition to bring wet weather to the State of CA. According to the CFS, this is not a short term transition. It is likely to continue for several weeks according to the latest Weeks 2, 3 and 4 of the Climate Forecast System. Of course the devil is in the details….. 😈
Todays medium and longer range charts from the ECMWF shows up to three systems next week. The first will weaken as it approach the So-Cal coast and so lighter amounts are expected as compared to the following two….. The GFS is still more generous with QPF for Southern CA than the ECMWF. However, both are similar by the week ending the 10th. The 2nd and 3rd system is better for the southern and central sierra as well…. I really like the 500mb height pattern by Mid-Month. It looks very wet for the Sierra and should give us a lot of snowfall.
Here is the Loading from the week 3 500 hPa issued the 28th from the CFS, week ending 1/19/2016
- Negative AO with upper height Anomaly of +120 meters
A 2nd upper height anomaly of +80 meters over the NW territories
- Another Upper Height anomaly of +90 meters near the dateline south of Kamchatka.
A subtropical height anomaly of greater than +50 meters centered SE of Hawaii.
- Most importantly, a deep negative height anomaly of -150 Meters is located near 135west with Negative height field east to California. (Looking very wet!)
I will update next weeks outlook, Friday January 1 by the evening…………
Happy New Year from the Dweebs.
Dr Howard and the Dweebs…………………………….:-)
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…………………..:-)