Biggest Storm of the Winter heads for the Sierra bringing Heavy Snow Blizzard Conditions and in the end…..Platinum Powder

3:00 PM Saturday, Cold Front now climbing the Sierra with the heaviest snowfall per hour now occurring.  Would expect WX front to be through by about 5:00PM and so there may be a brief break and actually some Blue Sky’s in back of the front before instability showers redevelop. Note: There is a band of showers developing in back of the front that seems to be spreading south. So snowfall rates will pick up again this evening….

The first storm will be very successful in bringing some 3 to 4 feet over the upper elevations by Sunday Morning…..

The next storm rolls late Sunday afternoon….. It will get windy Sunday night into Monday…

 

15:1 Platinum Powder should total between 1 and 2 feet between Monday night and Tuesday night.

 

Wednesday will be the day!!

 

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Platinum Powder Alert for Monday night into Tuesday for a foot or better of Platinum Powder…. S/W Ratios of at least 15:1 

Winter Storm Warning begins at 4:00PM this afternoon through Tuesday at 700PM

Blizzard Warning Sunday Night through Monday afternoon with snow drifts deeper than 10 feet in areas

Strong Gusty Winds as high as 50 MPH will accompany the heavy snowfall locally.

Snowfall amounts of between 4 and 10 feet are expected above 7000 feet within the time frame beginning tonight through Tuesday 7:00PM

In the Town of Mammoth, between 3 and 6 feet is possible within the Warning time frame

Forest Service Eastern Sierra Avalanche Center has issues an Avalanche Warning between Virginia Lakes to the north and Bishop Creek to the South.
Avalanche danger will become high in non controlled areas from Saturday morning through the weekend.

 

Discussion:

 

Surface low west of the Bay Area continues to deepen with cyclogenesis continuing….This first system is a slow mover and will make its way into the high country late tonight with heavy snow developing and continuing through Saturday night. If there is some kind of break it will be later Sunday morning before the next system hits Sunday night into Monday. Each successive storm will be colder with the last in the series Monday night into Tuesday bringing Modified Arctic air and cold dry powder. (Platinum Powder)  Wednesday looks to be Blue Bird at this time but another system may follow for the following weekend…  “Who Needs El Nino”  !!!!

 

The guidance suggests that up to 10 feet of snow is possible over the upper mountain on Mammoth Mt by Tuesday night….

Lions and Tigers and Giraffes….Oh My!!

 

PS, IF YOU HAVE TO TRAVEL DURING SOME OF THESE DANGEROUS PERIODS, BE SURE TO TAKE WARM BLANKETS, FOOD AND HAVE A FULL TANK OF GAS FOR YOUR CAR. IF YOU GET STUCK IN A BLIZZARD ON THE HIGHWAY, STAY IN YOUR CAR…

 

 

Dr Howard and the Dweebs…………………………:-)

 

 

 

 

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.