Archive for December, 2015
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…………………..:-)
Mammoth Mt Reports 14 to 30 inches of the lightest powder in years!! Snowshowers are expected this afternoon then Fair Saturday and warmer Sunday……
Friday December 25, 2015
Posted at 10:39 am by Howard
Monday’s weak storm is expected to bring 1 to 3 inches with possibly another inch or so blown in up in saddle bowl.
Once again the snow to water ratios will be high….
Although we have another small system that may bring a few more inches to the high country Monday, the focus now becomes the upcoming MJO induced +PNA pattern and the evolution of the break through or REX block under the +PNA itself. This is expected about end of the 1st week of January or just beyond…. The various runs of the deterministic GFS and ECMWF are quite fascinating now, and over the next 10 days the excitement will build for California as the actual ENSO induced pattern is expected to bring welcome relief to Southern CA as well as most of CA after four years of drought…..
The Dweebs right here will be in the Club Seats….giving you all, play by play explanation’s, as the tempo builds and the Mid Latitude and Southern Stream evolves…..
Christmas Day Morning:
Fabulous Snow….The Dweebs can hear the hooten and Hollering from Mammoth Mt to the Village…
14 to 30 inches of the lightest Platinum Powder fell yesterday and last night…And very much as good as the Rockies like to brag about!
Today is the day to make some turns…..
The forecast indicates some snow shower action this afternoon as a small vort center drops south…. Then a bit of a warm up Saturday into Sunday before a weakening system brings a few more inches on Monday…….
As we work though the Yuletide season and the end of the year….we begin to feel the effects weatherwise, of the strong MJO over the Maritime Continent. The convective envelop is so strong that the SOI has gone strongly positive (+30) indicating anomalous convection north of Australia and the Maritime continent….This will be temporary however, as the interseasonal wave continues east over the next 2 to 3 weeks….and then the SOI is likely to return negative with vengeance!
Through the Process:
- The (-PNA) pattern will become Positive (+PNA)
- This happens as the East Asian Jet retreats as the peddle come off the Upper Jet across the pacific and the west coast ridges up strongly.
- This will give us a glorious New Year’s over the far west with above normal temps over the upper elevations and gorgeous weather over Southern CA with highs in the 80s into the first week of January…
a. Strong inversions will likely develop over Mono County with Pogonip ice fog around New Years Day or shortly after around Lee Vining, Mono City as well as around Lake Crowley
b. In the eastern half of the country, winter will finally arrive from the Great Lakes to New England. The Strong Subtropical jet will likely keep a lot of the colder air confined to the northern sections.
- During the first week of January, most of the height rises will concentrate over Western Canada between BC and the Northern Rockies while California continues its fair-weather trend.
- Then the Magic of El Nino will likely develop for California during Week 2 of January.
a. With the +PNA pattern well established over Western Canada, and as the MJO remains strong into Phase 8….MJOs convective envelope shifts well through the Western Pacific as the East Asian Jet gets the peddle to the Meddle…
b. The upper jet reaches through the Eastern Pacific “about” the early part of the 2nd week of January as short wave systems are now forced east under the Western Canadian block into Central and Southern CA .
C. This is what Angeleno’s have been waiting for…..
Happy Holidays…………………………From the Dweeber!! 🙂