Winter Storm underway with heavy snowfall this afternoon into the Night….Snow Showers Sunday then Heavy Snow returning late Sunday night into Monday……A Longer Break Developing Wednesday into the Weekend….

1-15-2023 830am

Exciting meteorological development with this last significant storm.  The new ICON model 12z run shows the upper level wave with this last system, coming through Sacramento late morning while a surface low is over Monterey Bay at 400am and crosses the Sierra near Mammoth late AM. This will bring a bonus of snowfall to Mammoth Monday with some 3 more feet expected on the mountain. The Snow will be light powder with higher snow to water ratios than past systems this month. 12 or 13:1

I am still expecting another a smaller storm Wednesday night into Thursday with light to moderate amounts. The Euro is in some what agreement. See below…


Saturday night 9:55pm….1-14-2023


Just saw the new 00Z Sunday GFS model run.

Apparently,  this model run wants to dive the following short wave after Tuesday, further west to the Northern CA coast late Wednesday afternoon before progressing it through Central CA Thursday. Previous runs had this as an inside slider with mainly wind and very light snowfall. Well need to see the Euro come into agreement tomorrow and if it does, this new twist brings the possibility of moderate snowfall Wednesday night into Thursday. Preliminary estimates indicates between another 5 to 10 inches of snow if the Euro comes into agreement. Stay tuned….

After a decent break, Friday, Saturday 20th and 21st. into that early Sunday. The next system system drops south from Alberta and British Columbia, Canada. So it’s source region is dry and cold. It heads for Southern Nv and through the process,  can give us cold, windy, showery weather. This for Sunday night and Monday the 22nd and 23rd. Thereafter, as indicated in previous discussion, serious retrogression of the Eastern Pacific high begins to occur.

Sometime during the last week of January, we’re likely to see a major storm for California. I don’t see an AR yet but a strong subtropical tap could occur as the Trof that going to develop shows up as positive tilt and is deep as well.

Comment; while the storminess the past two weeks was not related the MJO forcing, the next storm cycle apparently is.


As of 9:00AM, Mammoth Mt has picked up about 9 to 12 inches of new snowfall since yesterday when the storm began. Another 4 to 5 feet is expected by Tuesday AM. Winter Storm Warnings are hoisted now through Tuesday at 10AM. Since the mountain has received about a foot, up to another 5 feet is expected by Tuesday AM.

Fridays System has passed bringing mainly light to moderate amounts. This current system has the AR attached to it so heavy amounts expected to develop later this morning into the evening. After somewhat of a break Sunday with very light snowfall, the last of this storm cycle will move in Sunday night with strong winds and heavy snowfall though Monday PM. Expect possible white out conditions in the morning.

The Monday/Tuesday system will be the last of the storm cycle. The pattern transits to an inside Slider Type/Great Basin low…Wednesday afternoon into Thursday. This pattern may offer some snow showers with gusty winds over the upper elevations and somewhat colder temps. Highs in Mammoth will be in the mid 20 mid-week. Then improving weather Friday into Saturday before another system Sunday afternoon into Monday dives north south into the Great Basin and desert southwest.  This is a windy pattern over the Sierra Crest and north wind prone areas. Some light snowfall is possible with light amounts if any.

The extended out for the following week shows another cold Great Basin Slider the 25th and 26th bringing the possibility of more upper elevation wind and light snow. The upper air hemispheric pattern is suggesting this morning that retrogression will begin to take place around the 26th. The MJO is strong going into Phase III of the RMM. (See previous post for that comment)   So odds are good that the eastern pacific high backs up again and a new storm cycle will begin just before the end of January.


Highs mid week in the mid 20s lows in the single digits and teens.


Dr Howard and the Dweebs…………….:-)

One more Major Snow Storm is expected Saturday through Tuesday AM….Then pattern trends dryer colder through that following weekend

1-13-2023  1:15pm

Interesting look at the longer range

According to the RIMM Phase space, The MJO will be moving into Phase III which is wetter for CA than phase II

See the composites for the MJO phase space for January.  The week two GFS and ECMWF has retrogression around that time and storms over the eastern pacific approaching CA.

This is not a forecast, rather just an interesting coincidence from the RIMM to what the Euro is showing 360 hours out or around the 26th to 28th of January.



1-13-2023 11:00AM

AM Update;

There are three periods with the pattern that are of interest;

  1. Light Warm Frontal Precip that has already developed today for a few inches that will continue into tonight with some additional 3 to 4 inches of snowfall possible. Amount’s are for the town.
  2. The next and heaviest precipitation producer moves in later Saturday AM with heavy snowfall into Saturday night. Some 1.5 to 2 feet is possible in town by early Sunday AM
  3. Sunday actually show more of a break in the intensity of the pattern with lighter snowfall accumulations.
  4. The next and perhaps strongest portion of the pattern without as much moisture to work with, moves in Later Sunday night. This storm has a surface low that comes right across the SFO Bay area. So it will be quite dynamic and produce heavy snowfall Monday AM with potential white out conditions in the Morning!!  The heaviest snow fall will taper off during the afternoon with snow likely into the early AM hours Tuesday.
  5. The Dweebs are still expecting over 3 feet in town and 4 to 6 feet on the mountain total by Tuesday AM.
  6. I will update the QPF this afternoon.


1-12-2023  10:25AM

Here are some very interesting Stats from today’s DWP Update;

  1. Southern Sierra on track for Wettest Winter in the past 40 years..
  2. Southern Sierra has an average of 276% of normal to date with 30 inches of water in snow pack
  3. Southern Sierra is 132% of normal for the entire water year
  4. Bishop is 374% of normal to date with 8.49 inches of water
  5. Bishop is 136% of normal for entire water year which ends September 2023

Mammoth Pass;

  1. Mammoth Pass has 40 inches of water to date.
  2. 40 inches is 94% of normal for the entire winter
  3. 40 Inches is also 201 % of normal for the date.
  4. DWP which is were this report comes from, indicates that we are ahead precipitation wise of any year on record.

Patterns in transition are difficult to nail down.

Just Looked at the ECMWF ensembles through the 25th and it shows a much drier pattern with the ridge building initially at 125-130W. With this scenario, we may get a chilly inside sider Thursday, but overall just some snow showers Thursday, followed by a dry weekend. It shows a strengthening ridge holding this weekend through next Tuesday the 24th. Thereafter, retrogression is indicated with the upper long wave ridge pushing back to 140W to 145W. This may open the door to some cold systems moving down the coast without ARs late in the month.

The latest GFS Ensembles has almost the same scenario, so confidence is high that a nice long break is ahead of us beginning next Friday through at least mid week the following week.

Next 5 days:

We have one more AR to deal with. It is a CAT 3.  So plenty of moisture.

It is interesting to note that the big Trof to the west of us will rotate counter clockwise and become negative tilt Friday for some over running precipitation. Eventually the flow becomes zonal as a short wave drops in the back side of that system. The system stretches West-East as the AR moves in Saturday. This should be good for Heavy Snowfall Saturday afternoon through the night. A final short wave moves in late Saturday night and is followed by much colder and unstable air for continued snowfall Monday. The back side of this trough moves in Tuesday AM, and light snow showers are indicated that day. So the wet pattern comes to an end.

Although there are are some model simulations that show a few cold storms the following weekend, the ensembles shows that it is unlikely to happen. Thus at this time, the Dweebs are going dry the 20th through the middle of that week…The 26th.

PS, Mammoth Mt could pick up another 4 to 5 feet by next Tuesday AM. 2.5 feet to 3.5 feet in town.

The California Rivers Forecast Center this afternoon shows 6.61 inches of water for Huntington Lake, beginning later Friday through early morning Tuesday. Tuesday looks dry Next Week.


Dr. Howard and the Dweebs………………:-)




Heavy Snow Today and Tonight…Periods of Heavy Snow Tuesday with Snow tapering off Tuesday night…More smaller systems This weekend into early next week with pattern changing by end of 3rd week of January…

Wow! snowfall rates are 3 inches an hour now on Mammoth Mountain!  Between 5:00AM this morning and 9:30AM; 12.5  inches fell at the Main Lodge in 4.5 Hours. That’s 3 inch’s an hour! Total since Saturday evening is 27 inches.

This is truly a dump, thanks to the Atmospheric River!

Snowfall totals are on track for at least 5 to 6 feet on the Mountain by Wednesday AM.

After this storm is over, snow showers will continue Wednesday. It will be dry Thursday and Friday.

There is a weak system that is splitting Friday night then another storm beginning Saturday morning that will bring solid moderate amounts into Sunday morning. About 1 to 2 feet. Sunday could be a bit of a break, then another system will bring a foot plus Monday and Monday night. The last in the series looks to be a moderate storm as well Tuesday night the 18th through the 19th.

Longer Range:

If all works out, we will have an extended break beginning the 20th.  There is some validation in this estimate based upon the MJO. Tropical Forcing…

See the RIMM Phase space w/MJO.

The MJO goes into Phase 2 which trends to be dry in January.  SEE Graphics below.