Weather Pattern to turn Active again as 3 Day Winter Storm could bring the largest totals of the season per storm this Winter! Wound up surface low to bring periods of strong gusty winds with blizzard conditions during two important periods…..Heavy Snowfall to develop Friday Night…with periods of heavy snow Saturday morning, Sunday and Monday……

The Weekend looks quite stormy with periods of heavy snow with little let up in the snowfall through Monday night….snow showers may continue into Tuesday. Latest guidance from the NAM shows a surface low undergoing rapid cyclogenesis with the surface low deepening from 1002MB 12Z friday to 979mb by 15Z Saturday west of Monterey Bay. This is just short of the classification of Bombogenesis which is 24MB of deepening within 24 hours. This trend is strengthening so will revisit in the morning. This will bring very strong winds to Coastal Bay Area FRIDAY NIGHT! The Golden Gate will be awesome! The cold front will be quite strong with heavy rains. Gradual weakening will occur as the front moves east but Heavy Snow in the Sierra a good bet, especially late Friday night into Saturday. It will be windy as well….

 

Next System moves in Sunday with heavy snow Sunday afternoon and Night.  gradients look strong enough for blizzard conditions Sunday Afternoon and night. Especially with the snow to water ratios increasing…

The last and final system has tapped modified arctic air from Western Canada with the coldest air of the season headed into Northern and Central CA. 700MB temps will fall to -17 or -18C by Tuesday AM.

Platinum Powder criteria is a possibility Monday and Monday night with 6 to 12 inches of the fluff possible by Tuesday AM.   Will consider Platinum Powder Watch tomorrow For Monday……

All considered, some 4 to 6 feet of new snow is a possibility for the period beginning later Friday afternoon through Monday night over Mammoth Mt with 2 to 3 feet in town the same time frame…..

Strong Ridge Trough Pattern to Break This Week as Eastern Pacific High Retrogrades just west of 140W Early Week 2…..Long Wave Trof to set up over the inter- mountain west for cold storms and fluffy snow Early Week 2….There may be a few small storms later this week….

The pattern change at this distance in time is a bit tricky as the Arctic air that is setting up over the Northern Midwest and Great Lakes region is forced to flush east and off shore by the next weekend… Initial track of pacific storms will be from the NW, through the west coast ridge that is breaking down this week for mainly light to possibly moderate precipitation with the best chance next weekend. Also we do not know how far west or how close to the coast the initial vort lobe is going to be that the GFS has in its proggs mid-week. No matter, this does not look like much. Just more of a nuisance system. The short wave is headed through high pressure and so light precip is mainly the possibily.

By the weekend or just beyond, the eastern pacific ridge retrogrades and amplifies just west of 140W, which in late January and early February is a cold pattern for CA. Long wave teleconnections suggests, coastal or inland sliders with varying amounts of over water trajectory. However, more time is needed to work out the details. A lot will depend upon how amplifyed the pattern gets.

MJO Support;

The GFS is consistent in its strong MJO through phase 7. The ECMWF is not as strong but at least is trending into 7 now….Good Support for a wet California week 2.

Familiar Ridge-Trough Pattern across the Country brings an end to the Active Pattern of the past several weeks….With Sierra Snowpack now above normal….Winter Sports are in Full Swing!!

Friday;

Ok, Sabbatical off but time off to move early next week….We do have a pattern change next week. Both the GFS and CFS, but not yet the ECMWF, are showing the MJO going into Phase 7 which can be wet in early February. SEE: http://www.cpc.noaa.gov/products/precip/CWlink/MJO/CLIVAR/clivar_wh.shtml

I use the Phase Space as support for the Global Models in the week two period. The MJO Composites do show more support in January for this pattern but early February is fine…. Phase 7 of the RMM2 supports retrogression for the Long Wave features over the eastern pacific (EP) to initially allow for the weakening of the west coast ridge, then retrogression of the feature afterword’s. The most likley pattern to develop is a cold Trof to set up either over the far west with some over water trajectory for light to moderate Cold Storms with light fluffy snow, or… further west for a cold-wetter scenario. There is also the possibility of subtropical moisture getting into the mix as one of the global models is trending to a REX Block, long enough to spin up a subtropical low with some phasing possibilities. We will not know how all this will come together for at least another 3 to 7 days when it gets into an earlier time frame. I will mention that “if”, and it is a big if, the MJO decides to remain strong and travels further east, toward and over the Nino Basin, that would be phases 8 then 1, which could end up a very wet pattern with an AR. So far the European model is not picking up on all this, either in its week two period or its MJO forecast. So, confidence is lower than what would be the case if the opposite were true. I would say that the odds are greater than 50% at this time.

In the meantime enjoy a weekend of January Thaw!! 🙂

Thursday Evening the 24th;

West Coast Ridge/Eastern Trof will dominate the pattern the next week with mostly sunny days and fair nights. High temperatures will range from the Mid 50s this weekend to the mid 40s next week. Nighttime temps in the 20s and teens. Expect light winds except over the Sierra Crest on Friday. The upper ridge does show some tendency to weaken by the end of the month, leading to lots of possibilities as we go through the first week of February. The GFS has the MJO forecasted to go into phase space 7 week 2, which can be wet this time of the year…. However, many of the models keep it in phase 6 which is dry. In the meantime, the Dweebs will take a sabbatical for the next 7 days unless there are clear signs of what kind of change is in store for us all…..The Dweeber…..:-)

A major pattern change is underway that will bring milder temperatures to the high country and an end to storminess for at least a week to ten days. The players and support show the MJO moving into Phase 6 next week in which composites show as dry for January in California and cold and wet in the east. This Ridge/Trough pattern is anchored by a deepening Hudson Bay Low and a highly amplified ridge over the far west. The Wave Length will be very stable. A January Thaw is likley to develop later this week sending high temps into the low 50s by the weekend. Lows at night at the village location will be in the teens by Mid week, then 20s over the weekend. At the Moment the Central Sierra is some 120% to 130% above normal in snowpack. Mammoth Mt is filled in with an 7 to 11 foot base, bottom to top. Skiing and riding are what you would expect on California’s favorite Mountain for this time of the year!

Next Series of storms will develop sometime during the Month of February…..Climate Model CFS V2 suggests possibly during the end of the first week in February…

In the meantime, high temperatures will go from the low 30s today Tuesday, to the low 50s by this weekend with cooler temperatures arriving by the following Monday.

As soon as the Dweebs have a better idea on a significant change, this blog will be updated…..In the meantime enjoy!!

Dr Howard and the Dweebs………………………..:-)