Mammoth Weather Outlook

Storm system winds down with snow showers today and partly cloudy Sky’s the next few days….Next storm becomes stationary Saturday night into next week with moderate amounts of Snowfall expected……The Week 2 Outlook still shows the East Asian Jet Progged to reach California the following weekend….




Apparently, the (CPC) “Climatic Prediction Center”  is “going for it” in their discussion today in regards to a pattern that can extend an “AR/Rs” to  CA.  I will wait a few more days to see if the European deterministic runs show the same.

Read Below:


6-10 DAY OUTLOOK FOR MAR 08 – 12 2023   Ensemble means from the 0z GEFS, ECMWF, and Canadian continue to depict troughing overspreading much of the contiguous U.S. (CONUS) during the 6-10 day period. Of note is that the deterministic solutions from the 00z GFS and ECMWF depict ridging building over the eastern CONUS, and are out of phase with the ensembles. Given the high latitude blocking and negative phase of the North Atlantic Oscillation forecast to be in place, along with a strong Madden Julian Oscillation (MJO) signal over the Western Hemisphere, the ensemble solutions remain preferred in today’s outlook. Today’s manual 500-hPa height blend for the 6-10 day period depicts below normal heights across most of the CONUS, with the exception of Florida and the Gulf of Mexico Coast where near normal heights are predicted. Positive height anomalies are indicated across Alaska underneath anomalous ridging over the North Pacific.




Mammoth Mt has had an impressive amount of snowfall this past Winter. As of today, the last storm dropped another 5.5 feet of fresh snow and snow totals now range from 56 feet at the top to 44 feet at the Main Lodge. In that there has not been a lot of snow melt this season, the snowpack is nothing short of astounding.

DWP just came out with their updated water survey showing Mammoth Pass now has 68.8 inches of water and is 168% of normal for this entire winter!   Of course this does not include what fell last night and this AM.



Our hemispheric pattern is going into transition. The RMM phase space is showing an MJO strengthening as it moves into Phase 7 over the Western Pacific.  Look at the Phase Space diagram below and see how strong it gets as it moves through Phase 7/8 . This has the affect of modulating the westerlies and can extend the East Asian Jet to the west coast. (Amplification then Retrogression) Many of our Pineapple and Mid Latitude AR’s are forced by this phenomenon during the Winter. There is no question, that the EAJ will extend toward the west coast now. However, there are a lot of questions about how that change to the pattern will effect California. As mentioned last post, it is too soon for a real forecast. However, as an outlook, since the potential event’s beginning, is some 8 days away, we can look at several possibilities through the week two period to make some guess on what may occur.  The event could last a week or more and often ends with a dry period and milder temperatures.

Again it is too soon for a Bonafede Forecast, and here are some of the latest longer range possibilities.

The week two Global Ensembles are coming this afternoon, which will add of detract to the CFS forecast below.


Please view these “with interest” and not a forecast. By the end of this week, there should be better confidence in what will occur later the following week.

At this time, the silver lining is that this does not look like a warm event.   Look at the graphic’s following as an example.










As you can see directly above, no agreement yet for an AR

Major Winter Snow Storm in Play…Break on Sunday with another Sunday Night into Tuesday Night…..Pattern Change is expected next weekend…..


Great News this AM….The Road is open to LA and most of All….The Sun is/was out!   Snow forecasts were right on with 4 to 4.5 feet on Mammoth Mt storm total. Temperatures were warming up today with highs approaching freezing. That’s a big difference compared to the past week!!


The next and may I add windy systems are moving in…Wind’s are increasing and Blizzard conditions will develop by this afternoon. Road closures are possible again, so if you have to be back to work Monday…Best to make haste and head south!.

2/27/23 7:30am update

The Next weather system will offer 3 short waves….So the long wave reloads….There are three impulses within the storms. Snowfalls of up to another 3 to 4 feet are expected in town and some 4 to 6 feet on Old Woolly by Wednesday afternoon.

What appear to be the last of the cold storms will move toward Mammoth later next weekend…..I say that as there is a strong Madden Julian Oscillation now forecasted by all Global Models. Below is an update graphic of its intensity in the RMM Phase Space. It is impressive!

As mentioned below, this Air Sea Coupled Phenomenon will likely modulate the westerlies toward Mid Month. The effect of this change is not completely known at this time. The pattern is likely to be associated with a closed Anti-Cyclone/Negative Phase EPO/WPO..  This will likely cause an extension of the East Asian Jet eastward toward the west coast. If the Closed High is centered far enough east, past the Dateline; A long wave trough will remain over the Eastern Gulf of AK and phase with the extended EAJ. In that case, expect a very significant AR or Pineapple Connection with the potential for very heavy precipitation reaching California between the 10th and 16th of March.  If the anticyclone sets up well west of the dateline, then we will ridge up and it will get warm with real spring weather. I think most folks would prefer the latter as we really do not want a warm wet or even cold AR hitting a 20+ foot snow pack!

In the meantime, the storms will remain cold with the current active pattern continuing tonight through mid afternoon Wednesday. Another cold storm is possible beginning next Saturday and Sunday after a dry Thursday and Friday


Stay Tuned…The Dweebs will have a better handle on the following weeks weather later this up coming week.






Older Discuession below from the 24th:

A major Winter storm is in play for the Central and Southern Sierra. Snow is falling at about 2+ inches an hour in Mammoth Lakes. “As of this time”, highway 395 is closed north of Pearsonville to Independence; and Gorge Rd in Inyo County to Walker. Check with Cal Trans for the latest!

(Note)  The Cal Trans Link above is getting a lot of traffic so keep trying as it is very busy!

The Owens Valley has moderate wind at the moment with Heavy Snowfall in many areas. Amounts expected generally will be 6 to 12 inches on the valley floor by Saturday night.  For the Town of Mammoth, The forecast is for between 2 to 3 feet in town and 3.5 to 4.5 feet on Mammoth Mt by Sunday AM. A new storm moves into Mono County Sunday night that will continue through Tuesday night.  Improving weather is expected Wednesday with Fair Weather expected Thursday and Friday.

Current Cold Pattern will be coming to an end for a while toward next weekend. According to the latest 12Z GFS deterministic model run this morning, there is a pattern change that looks to be taking place later next week or week after. Although there may be another storm later in that weekend, the pattern look drier after that following weekend.

Of some concern is what the MJO is forecasted to do toward and around the middle of March. I have posted the latest RMM Phase Space chart to show the MJOs strength as well as its location. It will be getting very amplified has it gets back into the RMM 7-8 area.   The MJO; “Madden Julian Oscillation” is supposed to be strong in this area toward mid March. It can force a “Pseudo El Nino effect” with higher heights in the PNA region, and sometimes, extend the East Asian Jet,  underneath a blocking high toward the west coast. At the least, the pattern over the far eastern pacific should become milder later week 2 into Week 3, with the absence of Arctic Air.  Milder weather could be just warmer or fair weather, or it could be milder and wet with storm’s associated with Atmospheric Rivers.

I will be watching with interest, what happens during that week 2 to week 3 period….

The Dweeber……….l👍









Dr Howard and the Dweebs…………………..:-)

Arctic Air Now Entrenched in the High Country…..Very Cold Temps along with gusty winds and strong wind chills…. Strong Winter Storm will exit through So-Cal Saturday with important effects for Southern Cal and the Owens Valley…..

Our Next winter storm has decided to make a change in its original track. Earlier, the track was to kick east through Baja, Mex. Now it is forecasted to kick inland over Southern CA. The center of the low will be over the Channel Islands at 1:00PM Saturday and over the Mojave Desert Saturday Evening. Of course as usual, the Weather Event is ahead of the low. Expect very unusual weather Friday Night through Saturday night with Blizzard Conditions in the San Gabriel Mts and heavy snowfall with some mountain areas getting up to 4 to 6 feet. Snow levels could be as low as 1500 feet.  Travelers should pay special attention to the NWS forecasts as this is a very dangerous storm for Mountain and high desert travelers, Friday through Saturday.

The main point here is that travel through the Owens Valley developing Friday through Saturday AM will be difficult or impossible. Snowfall amounts will be easily be in the 6 to 12 inch range by Friday night with some areas of 18 inches plus. Expect road closures, and if traveling, make sure you have warm blankets, food and water.  There will be period’s of blizzard conditions as well. Once again, check with current NWS forecasts from LA for the LA area, NWS  Las Vegas for the Owens Valley and KRNO for the Mono County area and Western Nevada. See WX links Below.

KRNO: Reno Discussion for Mono County

KVEF:   Las Vegas Discussion for the Owens Valley

LOX  (LA  Discussion)

Snowfall amounts for Mono County are expected to be 1 to 3 feet. Expect Blizzard conditions at times and road closures, The Storm will bring Platinum Powder to the high country with Amounts of 2 to 3+feet for Mammoth and Mammoth MT through Saturday night. Heaviest Snowfall will be Friday into Saturday.  Sunday will be a decent travel day if the roads are in good shape.  Another storm is expect to move in Monday into Tuesday. This is primarily a Sierra Storm.