Mammoth Weather Outlook

Enjoy one more day of 40s in Mammoth….More Arctic Air on the way for Tuesday Night through Friday as a repeat of the pattern earlier in the month expected…However with more over-water trajectory…… “Platinum Powder” Alert hoisted for Friday and Saturday…..


Lee Vining just flushed out of the fog at 9:40 AM as winds came up.

Storms on track. Friday into Friday Night System will be biggest snowfall producer. GFS now has the Closed Low ejecting Through Southern CA instead of Baja Saturday afternoon and evening. This would create a Pattern of Upslope Saturday into the night. So another 3 to 6 inches of snow is possible during that time, leaving Sunday to be the Blue Bird Day. Tweet Tweet.

Snowfall Between today and Saturday night will be 10 to 20 inches in town and 20 to 30 inches over the upper elevations.

Wednesday Night through Thursday Afternoon looks to be a time with the least amount of snowfall, like Saturday PM (3 to 6 inches)



Blue Bird Day Sunday.

New Storm moves in Monday….

There will be several more systems with over-water trajectory and without any AR’s noted next week.

The Dweeber………………..:-)


All the promise of large scale retrogression in the Hemi Pattern has backed off the next two weeks.  This means that storms will continue to be cold with light fluffy powder in moderate amounts. The longer range shows further retrogression week 3 toward the Middle of March, but the Dweebs are not biting on this yet, even though the MJO really touting it, as it reemerges into Phase 7 then 8.

The MJO has been successful enough for retrogression in getting the Long Wave Trof back over CA then west off shore. This will add to what is becoming one of the longest coldest winters in Eastern California in Memory. What is coming is nothing short of Misery for those that prefer traditional Sierra Weather vs Northern and Central Rockies type weather. However, some will be happy with traditional Rocky Mt Powder that might get kinda deep by Saturday AM. Snorkels anyone? The Dweeb in his younger years, remembers skiing the Big Burn at “Snowmass” in Aspen in 2+ feet of very light powder.  After a fall, that snow was hard to catch a breath in!

Back to the Meteorology, and after looking the 12Z GFS deterministic run for this week, as noted, this is true CPK air as the upper flow grabs some of the cold from the Hudson Bay PV as well as the NW Territories. If you have studied the weather in the Eastern US, you will know that they are becoming historically warm just as we are historically cold. As a note, we have had colder individual storms. However, the climatology of the persistence of cold is getting more and more notable in Mammoth for this winter.

This weeks active weather pattern begins tomorrow Tuesday. 1st with very strong winds as a stronger gradient is set up because of the Antecedent warmth ahead of a favorable Upper Jet Trajectory. As you can see below, the Arctic Ribbon pushes south through Mammoth Tuesday Evening in the 700MB chart and at 500MB the tap of CPK extends from well up in Canada! This is true modified Arctic Air!

700MB     Ribbon passing through Mammoth                                                                                500MB




Snowfall Amounts:

The west side of the Sierra is favored in the pattern for best precipitation.  Assuming that Snow to Water ratios are 15:1 through 4:00PM Wednesday Afternoon.  Amounts may be 6 to 10 inches over the crest and in town 3 to 5 inches of light fluffy snow from system number 1. System #2 will have more over water trajectory. It is slower moving as well. It is possible that the top of Mammoth Mt could get another 18 to 24 inches while in town 10 to 15 inches by early Saturday AM. This 2nd storm has the potential to bring the deepest light dry powder of the winter!  Don’t expect much more than another inch or two after Sunrise Saturday. For you outdoor enthusiast’s, the weather may offer a bit of a break this Saturday and Sunday in the storms.

There is another storm following. It is expected to begin Sunday night with another 1 to 2 feet possible by Tuesday evening. One again, this is another cold storm but possibly not as cold as the storms this week. After the early following week system, there looks to be a break Wednesday and Thursday before the possibility of a slightly milder wetter the following Friday. The not as cold and wetter scenario for the 3 and 4th is because of suggestion of further retrogression of the East PAC High,  which as of this point has failed to materialize, so not banking on it at this point.  There is a colder system for the 6th, 7th and 8th….But of course the further in time we go out the more the pattern is likely to change.  Below, look how crazy strong the MJO gets in Phase 7/8 toward the middle of March.   Not sure what is going to happen. But pretty scarry to the Dweebs….



Milder Temps on the way for the weekend with considerable high clouds……MJO now in favored 7/8 RMM phase space for retrogression of East Pac Ridge….Retrogression showing up in Global Models now over North Central Pac beginning this Monday the 20th…..A stormy week to begin about the 21/22st….


Saturday AM Quick update;

After a dry and milder weekend in the high country, the next active pattern will begin this Tuesday with increasing wind and the chance of light snow. Winds will be at least at advisory levels Tuesday night. This 1st storm is an Arctic Storm with once again “CPK” air from the NW territories of Canada. This means that it will get cold again like it did last Tuesday with highs in Mammoth in the upper teens and lows below zero. The East Pac High will be in retrogression across the Central and Eastern PAC. So weather systems will develops further off shore and become wetter at months end into 1st week of March.   Of Note, the models at this point have backed off on the idea of an Atmospheric River. Thus precipitation totals are half of what they were touted a week ago for the next week or two.  The precipitation forecasts (QPF) are now up to about 7 to 8 inch range (70 to 80) inches of snow over the crest over the next two weeks.  Should the Eastern Pacific Ridge become more positively tilt, that could would change the QPF forecast.

About the Arctic Express….

More 3 Dog Nights Ahead!

This has been one of the coldest winters in memory!  The next Arctic Express will push its Ribbon through our area during the night Tuesday. 1000MB-500MB thickness are progged down to 518DM Wednesday AM over Mono County. These thicknesses remain in the 520DMs through Friday AM. (Exceptional!) 700MB temps range from -13C to -17C Wednesday AM through Friday Night.

Any snow that falls during this period will be at ratios 15 to 20:1!  True “Platinum Powder” and Northern Rockies Quality!

The Next Cold system drops in the night of the 27th with more CPK air.  There is more over water trajectory with it so there will be more snowfall and it will be the fluffy type snow. It will begin Monday afternoon the 27th and continue through Tuesday the 28th.  At the moment there is a break March 1st through the 5th.


More Later……………………….


The Dweeber………………………:-)


The Dweebs have been posting about the MJO in RMM Phase Space 7/8 since February 11th in regards to the potential for retrogression of the Eastern Pac High.  The MJO (Madden Julian Oscillation) is a great tool during the winter as this climate mode can give lots of lead time for the next active pattern for our area. This tool on an intersessional time scale, is not an absolute tool to modulate the westerlies. However, more often than not can foretell of a significant pattern change for the Sierra during the Winter and most of all, can lend support to whether the week two models are on the right track..

This mornings RMM update posted below has an interesting twist to it.  While the MJO is now in phase space 7/8 foretelling retrogression, it weakens then reemerges strongly back into 7/8 later in March.  There are different modes of air-sea coupled systems creating upper divergence and upper convergence aloft over Indian Ocean, and down stream hemispherically. Modes include Equatorial Rossby Waves that travel East to West, Kelvin Waves that can push ocean subsurface warmth West to East and of course the MJO. Those that are interested should research these tropical modes of variability on the Net as this science is on the cutting edge of longer range forecasting, not only for Tropical Storms but their effects upon mid latitude circulation.





Look how the tracking of an MJO in Phase 7/8, dives into the circle of death later this month. Then another mode of tropical variability reemerges in phase 6, then progresses into 7 and 8 again about the middle of March. Phase 6 is usually drier for Northern California in March. Then Phase 7/8 can become wetter based upon the Lagg Composites. At this time, no one knows for sure what kind of mode of tropical variability it will be.  That is;  if this is an EQ Rossby Wave, MJO or possibility a big Typhoon over the Western Pac.

If it is an MJO; in March, the composites favor Southern CA in Phase 6, with low pressure off their coast. When in phase 7 then 8, the storm track becomes more active further north for Central CA and Northern CA.

As we know, phase 6 has been been very cold for the Eastern Sierra with little snow. This was the weather for early February, not March.


Fun to watch over the next 3 to 4 weeks…..

In the meantime, week two models are touting a wet pattern for CA beginning about mid week next week….

Amounts from the last two deterministic runs of the GFS are progging some 10 to 16 inches of water on the westside of the Sierra west of the Sierra Crest, beginning about the 23rd through the 4th of March.

As a Caveat, this is still in the outlook period and not a Bonnafied forecast yet…. So don’t panic!  There is plenty of time to make adjustments, within the week one period.


Stay Tuned….


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


Drier than normal weather will continue the next 1 to 2 weeks with cold inside and coastal sliders….Only light amounts of snowfall expected…….Next Retrogression of the Eastern Pacific Ridge not expected until about months end….


Expect clearing sky’s by this afternoon….

Brief update to indicate the current cold weather will be giving way to a milder weekend in the high country. Temps at 8000 feet will rise into the mid 40s Saturday and Sunday.  Monday, Presidents Holiday, may possibly get into the upper 40s. Lows currently in the single digits, are expected to move up into the teens then 20s…

As been touted….The RMM phase space has the MJO now over the Tropical West PAC in Phase 7. Further eastward movement is expected while weakening…  The Dweebs expect retrogression the Eastern Pacific High next week due to the MJO in Phase 7/8.  This means that storms that are now tracking from the NNW will retrograde, with the upper jet coming in from the Pacific as early as Tuesday night or Wednesday.  Further retrogression is expected later next week for wetter storms….Stay tuned….


Dr Howard and the Dweebs……………………:-)




Its the middle of February and we continue to be in this cold, drier than normal pattern. That looks to change the last week of February. The MJO is going into a favored phase space for retrogression of the Eastern Pacific Ridge; Phase Space’s 7/8.   I have attached that RMM chart for everyone’s perusal.  More often than not in the Winter, the MJO over the western central pacific causes wet weather for CA with an increase of subtropical moisture enhancement. Were going into the same area with the MJO that we were in, the first half of January when we had all that wet weather. So it will be interesting if history repeats itself to some extent. The forcing with this pattern is expected as early as the 21st but is better later in the month and into early March.

In the meantime, Its cold!  We had our highs today at 7:30AM and temps fell some eight degrees in town between 7:30AM and 8:00AM. The Arctic Ribbon pushed through our area about 8:00AM and you can see by the 700MB temp charts, temps going from -9C to -14C by 10:00AM.  During this push, the Bishop Airport had a temperature of 41 degrees at 6:30AM which dropped to 32 by 9:00AM.  Wind gusts increased to 60MPH at 8:00AM. There are wind advisories for the Owens Valley for strong north winds all day and into the night.

Its been snowing lightly in Mammoth this AM. It was 16 degrees at 10:00AM in town. Highs today will probably remain below 20 degrees today. The coldest air with this CPK air mass will be into our area about midnight tonight with (10,000ft) 700MB temps -17C.  There will be light snowfall accumulations today.  Expect moderating temps this weekend with mid 30s on Saturday up to the low 40s by Presidents Day Monday.

Look At the RMM chart below. Phases 7/8 is retrogression of the Eastern Pacific Ridge west of 140W during the last week of this month. More Moderate to Heavy Snowfall?





The colder than normal pattern we are curranty experiencing is highlighted by a weather system (Short Wave) about every 3 days. The upper ridge that governs the trajectory of the storm track is located over the North Eastern Pacific between 145 to 140 West. This position directs short waves down the West Coast or through the Great Basin. In that the coastal systems are moving mainly North to South, they lack any significant vertical motion fields for the Eastern Sierra. Any precipitation is usually deformation driven and confined to the western slopes. Any snowfall for Mammoth is usually in the light category with this pattern.

The systems that drop down through the Great Basin are picking up Arctic Air over the NW Territories’ of Canada. This cold air is modified somewhat as it moves through the Pacific NW and Great Basin. This Continental Air {CPK) will travel SE to Nevada, Monday night into Tuesday. This will affect the Eastern Slopes with very cold temps, and strong winds Monday night over the crest. CPK by nature is a dry airmass, however, can still provide some light upslope snowfall here in Mammoth Lakes. The CPK airmass is progged with -18C temps at (700MB )10,000 feet) here locally this Tuesday morning, for high temps in the lower 20s in town Tuesday (Valentines day). Lows in town Tuesday AM and Wednesday AM in the single digits. The Dweebs call this “Three Dog Night” sleeping weather!

The following system Friday the 17th is progged to be too far west for any significant snowfall as it heads south, for our high country. Then another very cold system with (CPK) air is progged for the Great Basin and California Monday the 20th.  Of note, the systems that drop into the Great Basin, are not only much colder, but have more potential for stronger North Winds, sooner for the Sierra Crest, then for the Owens Valley about a day later.

The current pattern in not likely to change before the last week of the month. Thereafter, the longer range models are hinting at Retrogression of the Eastern Pacific Ridge during the last week of the month for a greater chance of significant snow producing storms, anytime from the last week of February into the first week of March.


As usual stay tuned, as models are not perfect…..Just forgiven!


Dr Howard and the Dweebs……………..:-)