Steady Heavy Snowfall Has Turned To Showers Now As Long Wave Shifts Into The Great Basin

The new 12z Sunday model runs are now complete. They show the main long wave Trof slowly shifting east into the Great Basin over the next 12 hours. The axis of the long wave will be east of Mammoth by 00z Monday. There are two more short waves that will move through the long wave that will effect the Mammoth area the next two days. The first one rolls through early Monday morning and the other during the day Tuesday.

The Monday system has little over water trajectory and so it will be mostly showers beginning about midnight tonight and should be mostly through by sunrise Monday morning. Expect a few inches from that system.

The next and last in the series will have another good shot of Arctic air. It is better organized and has over water trajectory from the British Columbia coast…..south down and through Northern Ca.  Although the Northern Sierra is favored with this system, Mammoth Mountain may still pick up another 10 to 20 inches at again, a 20:1 ratio. Expect that the town will receive about half that amount.

Thereafter, a strong northerly flow will effect the high country Wednesday. Expect windy conditions over the crest. It will be sunny and cold  in town.  An upstream upper level ridge will move on shore Thursday. This will provide fair weather and the best skiing on the most  base on Mammoth Mountain, for so early in the season in over a decade!

Longer range:

Although all the global models are not quite in sync yet, using mainly the deterministic ECMWF. It appears that significant height falls will return to the California coast by late Friday night/Saturday morning  the 26th/27th  of November. This will lead toward the possibility of snow returning to the high country as early as Saturday. The Dweebs believe that snow will become more likely by the following Sunday. This new pattern is not associated with cold Arctic air like the present pattern. It is a more traditional pacific storm with relatively higher snow levels.

However…the screaming message this morning is that the Western Hemispheric Pattern continues to be progressive. And…..without effective blocking downstream, and favorable wave lengths, the storm door should continue to be open for the central west coast into the month of December………….:-)


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


Reference Glossary of Weather Terms

A break in the action today then snow becoming heavy again over night into Sunday AM

Our weather front sailed through nicely early this morning bringing close to 2 feet over the crest and some 10 to 15 inches around town. Short wave ridging will be sufficient to give us a nice break in the heavy snowfall Saturday afternoon, and although there will still be periods of snow, there will also be periods of sun!


5:45pm update:

The next really heavy snowy period will not develop until very late tonight and more likely after midnight. The period after midnight and before noon looks pretty ominous,  as the main upper low moves in and out of California. The upper trof should clear the Sierra by mid to late afternoon Sunday. Expect another break in the heavy snow mid afternoon Sunday into Sunday evening. The next short wave will redevelop more snowfall, again about midnight Sunday night with the last in the series late Monday night.

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In between short waves, lighter amounts of either snow or snow showers will still occur.  The Dweebs still believe that Mammoth Mountain will get up to 4 feet storm total…..hopefully a little more…..

The high resolution model WRF has the next short wave increasing the snowfall late Sunday night…especially after midnight. Another 6 to 12 inches could fall by noon Monday.

The WRF has yet another colder arctic system the the Dweebs will keep an eye on for the period, midnight Monday night into noon Tuesday.  Typically…the WRF beyond 48-60 hours is not as good as the Global models. The GFS has the Arctic low progressing east quicker with no over water trajectory lending to more of a snow showery pattern rather then the wetter WRFs scenario of another 1 foot plus between Late Monday night and noon Tuesday.  There will be plenty of time to adjust for this frigid system.


Fair, breezy and cold is the word Wednesday…then little wind in town with strong Mtn inversions developing Turkey day into Friday. 


Way off in Fantasy land…..the Dweebs are also keep an eye on a system that is moving into eastern Asia at the moment….. That may become a player in our weather about the time that visitors live for home a week from this Sunday.



Dr Howard and the Dweebs…………………..:-)


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Reference Glossary of Weather Terms

Getting Ready for a Mammoth Blizzard!!

Storm still looking good this morning.

There are four distinct features here:

1. The cold front will come through Mammoth about 11:00pm tonight. The bulk of the snowfall associated with the front with occur with and post frontal. So am not expecting snowfall to really pick up until later tonight.  WSFO RNO is expecting 3 to 5 inches in town by about sunrise.

2. First 500mb short wave comes through about 12 noon Saturday. So expect strong UVM between Sunrise and about 12:00pm Saturday along with moderate to heavy snow potential.

3.  There may or may not be much of a let up in precipitation between the 1200 noon and the passage of then next and main short wave which seems to have a double vort structure and drags through about Sunday mid afternoon.  There is going to be a very heavy period of snowfall between late Saturday afternoon and 12:00pm Sunday.

4. The 3rd short wave is being depicted by the GFS as an either NW west slider or inside slider while the NAM/WRF has still has some over water trajectory. Either way it look showery for Monday Am and of course cold. Snow totals still look good for up to 4 feet over the powder fields of Mammoth Mountain and a good two feet+ in the Village.

Of note, the new GFS as a few more sliders coming down over the great basin even as late at Wednesday, I do not expect much more then maybe some Mcflurries from them…..but it will be quite cold this coming week until Thanksgiving with moderating temps thereafter…..Longest range is hinting at some over running….later the following weekend……


Dr Howard and the Dweebs…………………………:-)


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Reference Glossary of Weather Terms