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Possible major storm 28NOV thru 2DEC

donbrown

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Mild Weather With Above Normal Temps to Continue a Few More Days before Subtropical Jet Exerts its Influence upon Mono County…..Wet Weather Ahead with more Base Building Precipitation Expected for Elevations Mainly above 9,000 ft Beginning Wednesday….


Monday November 26, 2012


Posted at 10:58 am by Howard
.

5:40pm Monday Update:

Confidence increasing for a long duration….high impact precipitation event for the northern and central sierra beginning Wednesday…..

18z GFS is less retrogressive now over the next 6 to 10 days……Stay tuned, we may get some cold air in here yet!!!!

Updates at anytime…..

Pattern changes are underway as more wet and wild weather will return for the high country the 2nd half of this week. We are now experiencing a weather type more like those back in the early 1980s where by a lot of Subtropical moisture will be entrained into Trofs. However at the moment…..most dynamics are to the north of Mammoth. In the developing weather type, the long wave is both too far west and too far north with retrogression in the cards next week. With the Mother Low Centered about 140west, the upper jet will move on shore over Northern Ca. Before it does, there will be coupling with the Subtropical Jet from time to time for enhancement off-shore. We here in Mammoth will have to rely a great deal upon the strong onshore flow as well as the natural orographics as a lifting mechanism. There will be plenty of moisture in the clouds but little in the way of upper divergence until a secondary system comes through at the end of the up coming cycle Saturday night into Sunday. QPF from CRFC has a pretty good bulls-eye over the northern part of the Southern Sierra for a 6 hour period Thursday afternoon. With the amount of heat released through the conversion process, it suggests snow levels rising up to at least 9K for a time. However, the Dweebs will have to take a good look at the OAK sounding 12z Thursday to see where the 0C line is at saturation and if the saturation is deep enough down to the surface at 7K or 8K for an extended snowfall to the surface. (A case for micro physical processes)

All in all at elevations above McCoy Station, there could be between 3 & 4 feet by Sunday night, taking in considerations for orographics. Questions now arise about what happens beyond next weekend…..

Thoughts:

The warmer waters off the Pacific Coast may be assisting in more ridging over the far west. Blocking from the Dateline north across the North Pole in the Means indicate the Arctic Oscillation is definitely screaming -AO!!!!!.. So why is the far west not stormier with the upper jet coming into Southern Ca? Because too much emphasis is put on the -AO and how all of the WX geeks just wanted the AO to go negative. Well its Negative. Are we waist deep in Snow? No…. Is the east coast waist deep in Snow? No! Teleconnections are useful, but they must couple properly with other teleconnections if they are going to be used as biases for predicting climate in various areas of the World. Yes the -AO is definitely plunging cold air into areas like Europe and the G of AK. But that happened with the Positive phase of the AO last year. So you can get the same results for a different sign!

Odds are as we go toward the middle of December, we will see an increase in the strength of the -NAO. The North Atlantic Oscillation. That will most likely bring Arctic cold to the Mid west and east next month. When both AO and NAO are strongly negative, you can count on the linnier relationship of cold in the east and warmth in the west with confidence. Of course, the PNA will respond strongly positive, especially if the west has warmer then normal SSTAs along the west coast as a support to the teleconnection. I see this in the future probably in later in Dec or January. Our classic Jan thaw while the east freezes!



The Global Wind Oscillation:

Now watch what is happening with the GWO. (Global Wind Oscillation) another interesting issue is that AIM has been on the increase now for the past several weeks. Phase 7-8 (El-Nino like) – the global relative AAM anomaly is positive. Westerly wind anomalies move into the Eastern Hemisphere, broaden in latitudinal extent and link up with deep westerly flow anomalies over the mid-latitude Western Hemisphere. An extended Pacific Ocean jet stream and southward shifted storm track is observed, favoring high impact weather events along the USA west coast. Central Ca to Pacific North west. This is now taking place in California!

Next move: Phase I

Phase 1 – the global relative AAM tendency is negative. Positive (westerly) AAM anomalies are being removed by surface friction in the Western Hemisphere mid-latitudes and through mountain torques across the Northern Hemisphere topography. The next phase of the oscillation (if it continues) is represented by easterly wind anomalies intensifying over equatorial regions of the Western Hemisphere. This phase has enhanced subtropical jets and closed lows in the subtropics favoring rainfall events over the southwestern USA. Possibly during the 2nd week of Dec for Ca.

SEE: http://www.esrl.noaa.gov/psd/map/images/gcm/gwo_40d.gif



Now see where the MJO goes over the next few weeks. (Phase 1) http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/NCPE_phase_21m_small.gif
 

bholmlate

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Lower yuba pass at Bassetts station looks like we need a little more the a few feet before we can ride at or around the gold lake area
ImageId1.jpg
 
Z
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:) Thinking Saturday will be the ride day,maybe Sunday.
Sonora,I hear you calling..I'll see you soon,not this weekend but soon.
Generally don't like the term Lower for snowmobileing,until Later.( smiley face)
 

bholmlate

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I would agree with you zilla. higher is definitly better this time a year but with expected snow level pushing 9000 feet usually means rain on an already low snow pack everywhere else
 

donbrown

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Mammoth expecting a couple feet at most in town by Monday with 2-5 feet at 10,000 feet. In town gonna snow then rain then snow.One More Decent Day then Showtime begins for Mother Nature….Lots of Possibilities….from Atmospheric River over Northern Ca…..To Protracted Precipitation Event….


Tuesday November 27, 2012


Posted at 12:57 am by Howard
.

Tuesday AM:

More western pacific TS phasing issues with new 12z GFS Run…..

Dweebs not happy with this particular run because how warm it will be.



Note: Snow levels and freezing levels are “not” the same!!

Overall still looking at two storms. The first rolls in Wednesday with “Freezing levels” about 8500 lowering to 7500 By Thursday AM. So snow levels will be below the level of town. IE a Plow for the plow guys by Friday AM

“Snowlevels” about 6.5K to 7K Wednesday then rising to 7500 to 8500 Thursday/NGT. QPF is .6 to 1.0 over the crest so some 3 to 6 inches is possible at the village with a foot+ at Main lodge by early Friday morning.

Freezing levels shoot up Friday afternoon with mainly rain/Snow mix at 8000ft. Then all rain in town Saturday afternoon through Sunday Morning as the freezing level in saturated air is at 10K. By Sunday afternoon the freezing levels come down along with the snow level. Snowfall accumulation increases again at 8000 ft beginning later in the afternoon and continues through Sunday night into Monday AM. 6 inches+ a possibility between late Sunday PM and Monday AM at the village.. 8050 ft

The crest will likely get 3 feet Plus of wet snow above 10,500 ft.


The snow will dry out late in the day Sunday into the night with falling temps with a foot+ additional between mid afternoon Sunday and Monday AM at the main lodge.

Next update this evening…..or sooner if warrented….



The Dweeber……………..:)

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donbrown

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Short Term “AR” Event Expected for Northern Ca…..Three Storms to Effect Our Area Over the Next 5 Days….


Wednesday November 28, 2012


Posted at 9:14 am by Howard
.

All models now in agreement that 3 distinct weather systems will effect the Northern and Central Sierra through Sunday. The first one rolls into the Sierra today about 9:00am. CRFC has 1.50 to 2.25 EQ, between Huntington Lake and Yosemite by about Sunrise Saturday. The precipitation will fall in the form of snow on Mammoth Mountain with the Snow level 7500 to 8000 feet. The Town of Mammoth may pick up between 1 and 3 inches at 8000 feet by this evening. On Mammoth Mountain 3 to 6 inches by this evening……


Thursday will be a day between systems with strong winds developing during the afternoon and the possibility of snow showers. The Dweebs do not expect much in the way of accumulation Thursday, possibly an inch over the upper elevations. There is a high wind watch for Thursday night through Friday for Mono County. Local winds may reach 65mph in gusts! High temps in the 40s…at 8,000ft.

Storm #2 has precipitation rates increasing by mid-morning friday. The snow level will be about 8000 feet. In the Town of Mammoth….4 to 8 inches of snow may fall at elevations above 8,000 by Saturday Am with 8 to 18 inches over the higher elevations above 9000ft. Strong winds will continue through friday.

With storm #3 approaching….Snow levels will rise all day Saturday and into the night as main Sub-tropical plume moves into the Sierra by late PM. Any new snowfall in the morning will change to Rain-Snow mix at 8,000 by Noon. The Snow level will rise to between 8500 and 9,000 feet by Saturday afternoon….then up to *9500 by midnight…..and 10,000+ feet by 4:00am Sunday. Rain will be heavy at times after midnight Saturday. The heaviest precip rates will occur between 4:00am Sunday and 10:00am Sunday….where an inch plus of rain could fall below 10K. Rainfall over snow pack often times just percolates down through the layers depending upon snow pack densities.

*Note: The Dweebs are using the freezing level as the snow level beginning Midnight Saturday through 10:00AM Sunday as the air-mass is expected to be saturated well beyond 12,000 feet.

Freezing levels and snow levels begin to come down about 10:00am Sunday…..then crash during the afternoon so that by 4:00pm the freezing level is down to 7,000 and a snow level south of 6,000. However, most of the precipitation will be over by then…..

The top of Mammoth Mountain may get a total of 4 to 5 feet of fresh snowfall by Sunday night. It is quite possibly that snowfall accumulations will exceed a foot at the “Main Lodge” between the very late morning Sunday and 4:00pm that afternoon….as freezing levels fall prior to the very end of the storm series…. Although quite a bit if rain may fall at the main lodge, the storm may leave 15 to 20 inches at the main lodge in its wake.
Expect cloudy dry weather Monday through Wednesday with warming temps…..

Long Range Outlook shows the upper ridge that is expected to build over California Monday thru Wednesday mid-week will retrograde over the following weekend to about 140west. This is going to be either a NW flow pattern or an insider slider pattern depending upon the amplification up stream. Either way…it will cool down, or get cold and showery with better snow making weather beyond the following weekend….



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

Scott

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Last night, our weather guesser said the coastal ranges could see up to 2 or 3 FEET of RAIN from this one.
 

Scott

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Wait,What? That would majorly flood most anywhere! Ca. the hills would slide.
Hope it does'nt happen in your area.

If there was 2 or 3 feet in the coastal ranges, it might hold on and drop 6 to 10 inches here in the mountains.

The prediction is for a couple to a few FEET of wet heavy here through the next 4 or 5 days.

I'll continue to hold my breath.
 
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